DESCRIPTION

Title of Invention

CONDUCTIVE SHEET, METHOD FOR USING CONDUCTIVE SHEET, AND CAPACITANCE TYPE TOUCH PANEL

Technical Field

The present invention relates to a conductive sheet, a method for using a conductive sheet, and a capacitive (capacitance type) touch panel, and for example to a conductive sheet suitable for use in a projected capacitive touch panel, a method for using a conductive sheet, and a capacitive touch panel.

Background Art

Studies have been made on transparent conductive films containing thin metal wires as disclosed in US Patent Application Publication No. 2004/0229028 and International Patent Publication No. 2006/001461, etc.

Touch panels have attracted much attention in recent years. Though the touch panels have currently been used mainly in small devices such as PDAs (personal digital assistants) and mobile phones, they are expected to be used in larger devices such as personal computer displays.

A conventional electrode for the touch panel is composed of ITO (indium tin oxide) and therefore has a high resistance. Thus, in a case where the electrode is used in the larger device in the above future trend, the large-sized touch panel disadvantageously has a low current transfer rate between electrodes and thereby exhibits a low response speed (a long time between finger contact and touch position detection).

A large number of lattices composed of thin wires of a metal (thin metal wires) can be arranged to form an electrode with a lowered surface resistance. A touch panel using the electrode of the thin metal wires is known from patent documents of Japanese Laid-Open Patent Publication No. 05-224818, US Patent No. 5113041, International Patent Publication No. WO 1995/27334, US Patent Application Publication No. 2004/0239650, US Patent No. 7202859, International Patent Publication No. WO 1997/18508, and Japanese Laid-Open Patent Publication No. 2003-099185, etc.

Summary of Invention

However, in the case of using the thin metal wires in the electrode, the thin metal wires are composed of an opaque material, whereby the electrode has problems of transparency and visibility.

In view of the problems, an object of the present invention is to provide a conductive sheet capable of exhibiting a high transparency in a touch panel even in the case of using an electrode composed of a thin metal wire pattern, a method for using a conductive sheet, and a capacitive touch panel.

[1] A conductive sheet according to a first aspect of the present invention comprising a substrate and a conductive part formed on the substrate, wherein the conductive part contains two or more conductive large lattices composed of a thin metal wire and a connection composed of a thin metal wire for electrically connecting the adjacent large lattices, the large lattices each contain a combination of two or more small lattices, the large lattices are combined to form a circuit, and the connection has a width Wc, the small lattices have a pitch Ps, and the width Wc and the pitch Ps satisfy the relation Wc > Ps/V2.

[2] The conductive sheet according to the first aspect, wherein two or more of the large lattices are arranged in a first direction with the connection disposed therebetween to form a conductive pattern, two or more of the conductive patterns are arranged in a second direction perpendicular to the first direction, an electrically isolated insulation not containing the small lattices is disposed between the adjacent conductive patterns, and the conductive patterns and the insulation are arranged to form the circuit.

[3] The conductive sheet according to the first aspect, wherein the large lattices have a side length of 3 to 10 mm.

[4] The conductive sheet according to the first aspect, wherein the small lattices have a side length of 30 to 500 μm

[5] The conductive sheet according to the first aspect, wherein sides facing each other in the small lattices are disposed at a distance of 30 to 500 μm.

[6] The conductive sheet according to the first aspect, wherein the thin metal wire has a line width of 10 μ m or less.

[7] A conductive sheet according to a second aspect of the present invention comprising a substrate, a first conductive part formed on one main surface of the substrate, and a second conductive part formed on the other main surface of the substrate, wherein the first conductive part contains two or more conductive first large lattices composed of a thin metal wire and a first connection composed of a thin metal wire for electrically connecting the adjacent first large lattices, the second conductive part contains two or more conductive second large lattices composed of a thin metal wire and a second connection composed of a thin metal wire for electrically connecting the adjacent second large lattices, the first large lattices and the second large lattices each contain a combination of two or more small lattices, the first large lattices are arranged in a first direction with the first connection disposed therebetween to form a first conductive pattern, the first large lattices and the second large lattices are combined to form a circuit, and the first connection has a width Wc1, the second connection has a width Wc2, the small lattices have a pitch Ps, and the width Wcl, the width Wc2, and the pitch Ps satisfy the relations Wcl > Ps/√2, and Wc2 > Ps/√2.

[8] The conductive sheet according to the second aspect, wherein the first large lattices are arranged in the first direction with the first connection disposed therebetween to form the first conductive pattern composed of the thin metal wire, two or more of the second large lattices are arranged in a second direction perpendicular to the first direction with the second connection disposed therebetween to form a second conductive pattern composed of the thin metal wire, an electrically isolated first insulation not containing the small lattices is disposed between the adjacent first conductive patterns, an electrically isolated second insulation not containing the small lattices is disposed between the adjacent second conductive patterns, the first conductive patterns, second conductive patterns, the first insulation, and the second insulation are arranged to form the circuit.

[9] The conductive sheet according to the second aspect, wherein the thin metal wire has a line width of 10 |xm or less.

[10] The conductive sheet according to the second aspect, wherein a projected distance between straight lines of a side of the first large lattices and a side of the second large lattices is selected based on a size of the small lattices.

[11] The conductive sheet according to the second aspect, wherein the projected distance is 100 to 400 μm

[12] The conductive sheet according to the second aspect, wherein the first conductive part further contains first terminal wiring patterns each connected to an end of the first conductive pattern and a plurality of first terminals each connected to the corresponding first terminal wiring pattern, the first terminals being formed in a longitudinal center of a side on the one main surface of the substrate, and the second conductive part further contains second terminal wiring patterns each connected to an end of the second conductive pattern and a plurality of second terminals each connected to the corresponding second terminal wiring pattern, the second terminals being formed in a longitudinal center of a side on the other main surface of the substrate.

[13] The conductive sheet according to the second aspect, wherein an arrangement of a plurality of the first terminals is adjacent to an arrangement of a plurality of the second terminals as viewed from above.

[14] The conductive sheet according to the second aspect, wherein an end of each of the first conductive patterns is connected to the corresponding first terminal wiring pattern by a first wire connection, an end of each of the second conductive patterns is connected to the corresponding second terminal wiring pattern by a second wire connection, a plurality of the first wire connections are arranged in a straight line along the second direction, and a plurality of the second wire connections are arranged in a straight line along the first direction.

[15] The conductive sheet according to the second aspect, wherein the first insulation and the second insulation are arranged facing each other with the substrate interposed therebetween, and the overlap of the first insulation and the second insulation has a polygonal shape as viewed from above.

[16] The conductive sheet according to the second aspect, wherein the polygonal shape is a square shape.

[17] The conductive sheet according to the second aspect, wherein the polygonal shape is a wedge shape.

[18] The conductive sheet according to the first or second aspect, wherein the small lattices have a polygonal shape.

[19] The conductive sheet according to the second aspect, wherein the small lattices have a square shape.

[20] A method for using a conductive sheet according to a third aspect of the present invention, comprising using a first conductive sheet and a second conductive sheet.

wherein the first conductive sheet contains two or more conductive first large lattices composed of a thin metal wire and a first connection composed of a thin metal wire for electrically connecting the adjacent first large lattices, the first large lattices each contain a combination of two or more small lattices, the first connection has a width Wcl, the small lattices have a pitch Ps, and the width Wcl and the pitch Ps satisfy the relation Wcl > Ps/√2, the second conductive sheet contains two or more conductive second large lattices composed of a thin metal wire and a second connection composed of a thin metal wire for electrically connecting the adjacent second large lattices, the second large lattices each contain a combination of two or more small lattices, the second connection has a width Wc2, the small lattices have a pitch Ps, and the width Wc2 and the pitch Ps satisfy the relation Wc2 > Ps/√2, two or more of the first large lattices are arranged in a first direction with the first connection disposed therebetween to form a first conductive pattern in the first conductive sheet, two or more of the second large lattices are arranged in a second direction perpendicular to the first direction with the second connection disposed therebetween to form a second conductive pattern in the second conductive sheet, and the first conductive sheet and the second conductive sheet are combined, so that the first connection in the first conductive sheet and the second connection in the second conductive sheet form in combination an arrangement of the small lattices.

[21] A capacitive touch panel according to a fourth aspect of the present invention comprising the conductive sheet according to the first or second aspect.

As described above, in the conductive sheet and the conductive sheet using method of the present invention, the conductive pattern formed on the substrate can have a lowered resistance, the conductive sheet can exhibit a high transparency in a touch panel even in the case of using the electrode composed of the thin metal wire pattern, and the conductive sheet can be suitably used in a projected capacitive touch panel or the like.

Furthermore, in the capacitive touch panel of the present invention, the conductive pattern formed on the substrate can have a lowered resistance, the capacitive touch panel can exhibit a high transparency even in the case of using the electrode composed of the thin metal wire pattern, and the capacitive touch panel can be suitably used as a large-sized projected capacitive touch panel or the like.

Brief Description of Drawings

FIG. 1 is a plan view showing a pattern example of a first conductive pattern formed on a first conductive sheet;

FIG. 2 is a cross-sectional view partially showing the first conductive sheet;

FIG. 3 is an exploded perspective view showing a structure of a touch panel;

FIG. 4 is an exploded perspective view partially showing a first laminated conductive sheet;

FIG. 5A is a cross-sectional view partially showing an example of the first laminated conductive sheet, and FIG. 5B is a cross-sectional view partially showing another example of the first laminated conductive sheet;

FIG. 6 is a plan view showing a pattern example of a second conductive pattern formed on a second conductive sheet;

FIG. 7 is a plan view partially showing an example of the first laminated conductive sheet obtained by combining the first and second conductive sheets;

FIG. 8A is a schematic view showing a first structure example using an antireflection film, FIG. 8B is a schematic view showing a second structure example using a similar film, and FIG. 8C is a schematic view showing a second structure example using a similar film;

FIG. 9 is an exploded perspective view partially showing a second laminated conductive sheet;

FIG. 10 is a plan view showing a pattern example of a first conductive pattern formed on a first conductive sheet in the second laminated conductive sheet;

FIG. 11 is a plan view showing a pattern example of a second conductive pattern formed on a second conductive sheet in the second laminated conductive sheet;

FIG. 12 is a plan view partially showing an example of the second touch panel conductive sheet obtained by combining the first and second conductive sheets;

FIG. 13 is a plan view showing a pattern example of a first conductive pattern formed on a first conductive sheet in a laminated conductive sheet according to a modified example;

FIG. 14 is a plan view showing a pattern example of a second conductive pattern formed on a second conductive sheet in the laminated conductive sheet according to the modified example;

FIG. 15 is a flow chart of a method for producing a transparent conductive film according to an embodiment of the present invention;

FIG. 16A is a cross-sectional view partially showing a prepared photosensitive material, and FIG. 16B is an explanatory view showing a simultaneous both-side exposure of the photosensitive material; and

FIG. 17 is an explanatory view showing first and second exposure treatments performed such that a light incident on a first photosensitive layer does not reach a second photosensitive layer and a light incident on the second photosensitive layer does not reach the first photosensitive layer.

Description of Embodiments

Several embodiments of the conductive sheet, the conductive sheet using method, and the capacitive touch panel of the present invention will be described below with reference to FIGS. 1 to 17. It should be noted that, in this description, a numeric range of "A to B" includes both the numeric values A and B as the lower limit and upper limit values.

As shown in FIG. 1, a conductive sheet according to a first embodiment of the present invention (hereinafter referred to as a first conductive sheet 10A) has a first conductive part 13A formed on one main surface of a first transparent substrate 12A (see FIG. 2). The first conductive part 13A contains two or more conductive first large lattices 14A composed of thin metal wires and a first connection 16A composed of thin metal wires for electrically connecting the adjacent first large lattices 14A. Each of the first large lattices 14A contains a combination of two or more small lattices 18, and the first large lattices 14A are combined to form a circuit (a conductive circuit pattern). The small lattices 18 have a smallest square shape in this embodiment. For example, the thin metal wires contain gold (Au), silver (Ag), or copper (Cu).

The side length of the first large lattice 14A is preferably 3 to 10 mm, more preferably 4 to 6 mm. If the side length is less than the lower limit, in the case of using the first conductive sheet 10A in a touch panel or the like, the first large lattice 14A exhibits a lowered electrostatic capacitance in a detection process, and the touch panel is likely to cause a detection trouble. On the other hand, if the side length is more than the upper limit, the position detection accuracy may be deteriorated. The side length of each small lattice 18 in the first large lattice 14A is preferably 50 to 500 \xm, more preferably 150 to 300 urn, for the same reasons. In a case where the side length of the small lattice 18 is within this range, the first conductive sheet 10A can have excellent transparency and thereby can be suitably used at the front of a display device with excellent visibility.

Two or more of the first large lattices 14A are arranged in an x direction (a first direction) with the first connection 16A disposed therebetween, to form one conductive circuit pattern composed of the thin metal wires (hereinafter referred to as a first conductive pattern 22A). Two or more of the first conductive patterns 22A are arranged in a y direction (a second direction) perpendicular to the x direction. Electrically isolated first insulations 24A containing no small lattices 18 are disposed between the adjacent first conductive patterns 22A.

For example, the x direction corresponds to the horizontal or vertical direction of a projected capacitive touch panel 100 or a display panel 110 equipped with the touch panel 100 to be hereinafter described (see FIG. 3).

As shown in FIG. 1, among four sides of the first large lattice 14A, a first side 28a and a second side 28b are on one corner 26a not connected to the adjacent first large lattice 14A. A continuous straight line 30 extends along each of the first side 28a and the second side 28b, and a large number of needle-like lines 32 (sides of the small lattices 18) extend from the straight line 30 to form a comb-like shape. The line 32 is hereinafter referred to also as the comb tooth 32. Furthermore, a third side 28c and a fourth side 28d are on the other corner 26b not connected to the adjacent first large lattice 14A. A continuous straight line 30 extends along each of the third side 28c and the fourth side 28d, and one small lattice 18 is removed (more specifically adjacent two sides are removed) in the other corner 26b.

In the first connection 16A, four medium lattices 20 (a first medium lattice 20a to a fourth medium lattice 20d) are arranged in a zigzag manner, and each of the medium lattices 20 has a size equal to the total of four small lattices 18. The first medium lattice 20a is disposed at the intersection of the straight lines 30 of the second side 28b and the fourth side 28d, and forms an L-shaped space in combination with one small lattice 18. The second medium lattice 20b is disposed on one side of the first medium lattice 20a (the straight line 30 of the second side 28b), and forms such a square space that four small lattices 18 are arranged in a matrix and the central cross is removed. The third medium lattice 20c is adjacent to the first medium lattice 20a and the second medium lattice 20b, and has the same shape as the second medium lattice 20b. The fourth medium lattice 20d is disposed between the first side 28a and the 2nd straight line 30 along the third side 28c (the 2nd straight line 30 in the direction from the outside to the inside of the first large lattice 14A), is adjacent to the second medium lattice 20b and the third medium lattice 20c, and forms an L-shaped space in combination with one small lattice 18 as in the first medium lattice 20a. One side of the fourth medium lattice 20d is disposed on an extended line of the straight line 30 along the fourth side 28d of the first large lattice 14A. If the small lattices 18 have an arrangement pitch Ps, the medium lattices 20 have an arrangement pitch Pm of 2 x Ps. In addition, the first connection 16A has a width Wc1 (which is a distance in the y direction between a vertex of the second medium lattice 20b and a vertex of the third medium lattice 20c), and the width Wcl satisfies the relation Wcl > Ps/√2. In this embodiment, the width Wcl is 6 x (Ps/√2).

In one end of each first conductive pattern 22A, the first connection 16A is not formed on the open end of the first large lattice 14A. In the other end of the first conductive pattern 22A, the end of the first large lattice 14A is electrically connected to a first terminal wiring pattern 41a composed of a thin metal wire by a first wire connection 40a (see FIG. 3).

As described above, in the first conductive sheet 10A, the first conductive pattern 22A is formed by arranging two or more first large lattices 14A in the x direction with the first connection 16A interposed therebetween, the first large lattice 14A is formed by combining two or more small lattices 18, and the width Wcl of the first connection 16A and the pitch Ps of the small lattices 18 satisfy the relation Wcl > Ps/^2. As a result, the first conductive sheet 10A can exhibit a significantly lowered electrical resistance as compared with conventional structures using one ITO film for one electrode. Thus, if the first conductive sheet 10A is used in the projected capacitive touch panel or the like, the response speed and the size of the touch panel can be easily increased.

The touch panel 100 containing the above first conductive sheet 10A will be described below with reference to FIGS. 3 to 7.

The touch panel 100 has a sensor body 102 and a control circuit such as an integrated circuit (not shown). As shown in FIGS. 3, 4, and 5A, the sensor body 102 contains a touch panel conductive sheet according to the first embodiment (hereinafter referred to as a first laminated conductive sheet 50A) and thereon a protective layer 106 (not shown in FIG. 5A). The first laminated conductive sheet 50A is obtained by stacking the above first conductive sheet 10A and a second conductive sheet 10B to be hereinafter described. The first laminated conductive sheet 50A and the protective layer 106 are disposed on the display panel 110 of a display device 108 such as a liquid crystal display. As viewed from above, the sensor body 102 has a sensing region 112 corresponding to a display screen 110a of the display panel 110 and a terminal wiring region 114 (a so-called frame) corresponding to the periphery of the display panel 110.

As shown in FIG. 4, in the first conductive sheet 10A of the touch panel 100, a large number of the first conductive patterns 22A are arranged in the sensing region 112, and a plurality of the first terminal wiring patterns 41a composed of the thin metal wires extend from the first wire connections 40a in the terminal wiring region 114.

In the example of FIG. 3, the first conductive sheet 10A and the sensing region 112 each have a rectangular shape as viewed from above. In the terminal wiring region 114, a plurality of first terminals 116a are arranged in the length direction in the longitudinal center of the periphery on one long side of the first conductive sheet 10A. The first wire connections 40a are arranged in a straight line in the y direction along one long side of the sensing region 112 (a long side closest to the one long side of the first conductive sheet 10A). The first terminal wiring pattern 41a extends from each first wire connection 40a to the approximate center of the one long side of the first conductive sheet 10A, and is electrically connected to the corresponding first terminal 116a. Thus, the first terminal wiring patterns 41a, connected to each pair of corresponding first wire connections 40a formed on the right and left of the one long side of the sensing region 112, have approximately the same lengths. Of course, the first side 28d is separated in the alternate small lattices 18. Thus, the two or more rectangles are arranged to form the rectangular wave shape on each of the first sides 28a to the fourth sides 28d of the first large lattices 14A in the second laminated conductive sheet 50B. Particularly, in the first large lattice 14A, the rectangles on the first side 28a are alternated with those on the fourth side 28d opposite to the first side 28a, and the rectangles on the second side 28b are alternated with those on the third side 28c opposite to the second side 28b.

Similarly, as shown in FIG. 11, the second large lattice 14B in the second laminated conductive sheet 50B is such that each alternate comb tooth 32 on the fifth side 28e and the seventh side 28g of the second large lattice 14B in the second conductive sheet 10B shown in FIG. 6 is connected to the next comb tooth 32 to form the small lattice 18 and each straight line 30 on the sixth side 28f and the eighth side 28h is separated in the alternate small lattices 18. Thus, the two or more rectangles are arranged to form the rectangular wave shape on each of the fifth sides 28e to the eighth sides 28h of the second large lattices 14B in the second conductive sheet 10B. Particularly, in the second large lattice 14B, the rectangles on the fifth side 28e are alternated with those on the eighth side 28h opposite to the fifth side 28e, and the rectangles on the sixth side 28f are alternated with those on the seventh side 28g opposite to the sixth side 28f.

For example, as shown in FIG. 12, in a case where the first conductive sheet 10A is stacked on the second conductive sheet 10B to form the second laminated conductive sheet 50B, as in the first laminated conductive sheet 50A (see FIG. 7), the first connections 16A of the first conductive patterns 22A and the second connections 16B of the second conductive patterns 22B are arranged facing each other with the first transparent substrate 12A (see FIG. 5A) in between, and also the first insulations 24A between the first conductive patterns 22A and the second insulations 24B between the second conductive patterns 22B are arranged facing each other with the first transparent substrate 12A in between. Though the first conductive patterns 22A and the second conductive patterns 22B have the same line width, they are exaggeratingly shown by thick lines and thin lines respectively to clearly represent the positions thereof in FIG. 12 as well as FIG. 7,

In a case where the stacked first conductive sheet 10A and second conductive sheet 10B are viewed from above, the spaces between the first large lattices 14A of the first conductive sheet 10A are filled with the second large lattices 14B of the second conductive sheet 10B. In this case, the opening of each concave 42a on the rectangular wave shapes of the first sides 28a and the second sides 28b in the first large lattices 14A is closed by the end of each convex 42b on the rectangular wave shapes of the sixth sides 28f and the eighth sides 28h in the second large lattices 14B, to form an arrangement of the small lattices 18 as viewed from above. Similarly, the opening of each concave 42a on the rectangular wave shapes of the third sides 28c and the fourth sides 28d in the first large lattices 14A is closed by the end of each convex 42b on the rectangular wave shapes of the fifth sides 28e and the seventh sides 28g in the second large lattices 14B, to form an arrangement of the small lattices 18 as viewed from above. As a result, the boundaries between the first large lattices 14A and the second large lattices 14B cannot be easily found. Thus, the openings of the concaves 42a overlap with the ends of the convexes 42b in the rectangular wave shapes, whereby the boundaries between the first large lattices 14A and the second large lattices 14B are less visible to improve the visibility. Though a cross-shaped opening is formed in each overlap of the first insulation 24A and the second insulation 24B, the opening does not block a light and is less visible unlike the above thickened line.

In the overlaps of the first connections 16A and the second connections 16B in the second laminated conductive sheet 50B, as in the first laminated conductive sheet 50A, the connection point of the fifth medium lattice 20e and the seventh medium lattice 20g in the second connection 16B is positioned approximately at the center of the second medium lattice 20b in the first connection 16A, the connection point of the sixth medium lattice 20f and the eighth medium lattice 20h in the second connection 16B is positioned approximately at the center of the third medium lattice 20c in the first connection 16A, and the first medium lattices 20a to the eighth medium lattices 20h form a plurality of the small lattices 18 in combination. Therefore, the first connections 16A and the second connections 16B are combined to form the small lattices 18 in the overlaps thereof. Thus formed small lattices 18 cannot be distinguished from the surrounding small lattices 18 in the first large lattices 14A and the second large lattices 14B, so that the terminals 116a may be formed in a corner of the first conductive sheet 10A or the vicinity thereof. However, in this case, the length difference between the longest first terminal wiring pattern 41a and the shortest first terminal wiring pattern 41a is increased, whereby the longest first terminal wiring pattern 41a and the first terminal wiring patterns 41a in the vicinity thereof are disadvantageously poor in the rate of transferring a signal to the corresponding first conductive pattern 22A. Thus, in this embodiment, the first terminals 116a are formed in the longitudinal center of the one long side of the first conductive sheet 10A, whereby the local signal transfer rate deterioration is prevented to increase the response speed.

As shown in FIGS. 3, 4, and 5A, the second conductive sheet 10B has a second conductive part 13B formed on one main surface of a second transparent substrate 12B. The second conductive part 13B contains two or more conductive second large lattices 14B composed of thin metal wires and a second connection 16B composed of thin metal wires for electrically connecting the adjacent second large lattices 14B. As shown in FIG. 6, each of the second large lattices 14B contains a combination of two or more small lattices 18. The second connection 16B contains one or more medium lattices 20, and the pitch of the medium lattices 20 is n times larger than that of the small lattices 18 (in which n is a real number larger than 1). The side length of the second large lattice 14B is preferably 3 to 10 mm, more preferably 4 to 6 mm, as well as the first large lattice 14A.

Two or more of the second large lattices 14B are arranged in the y direction (the second direction) with the second connections 16B disposed therebetween to form one conductive circuit pattern composed of the thin metal wires (hereinafter referred to also as the second conductive pattern 22B), and two or more of the second conductive patterns 22B are arranged in the x direction (the first direction) perpendicular to the y direction. Electrically isolated second insulations 24B containing no small lattices 18 are disposed between the adjacent second conductive patterns 22B.

As shown in FIG. 4, for example, in one end of each alternate odd-numbered second conductive pattern 22B and in the other end of each even-numbered second conductive pattern 22B, the second connection 16B is not formed on the open end of the second large lattice 14B. In the other end of each odd-numbered second conductive pattern 22B and in one end of each even-numbered second conductive pattern 22B, the end of the second large lattice 14B is electrically connected to a second terminal wiring pattern 41b composed of a thin metal wire by a second wire connection 40b.

A large number of the second conductive patterns 22B are arranged in the sensing region 112, and a plurality of the second terminal wiring patterns 41b extending from the second wire connections 40b are arranged in the terminal wiring region 114.

As shown in FIG. 3, in the terminal wiring region 114, a plurality of second terminals 116b are arranged in the length direction in the longitudinal center of the periphery on one long side of the second conductive sheet 10B. For example, the odd-numbered second wire connections 40b are arranged in a straight line in the x direction along one short side of the sensing region 112 (a short side closest to one short side of the second conductive sheet 10B), and the even-numbered second wire connections 40b are arranged in a straight line in the x direction along the other short side of the sensing region 112 (a short side closest to the other short side of the second conductive sheet 10B).

For example, among a plurality of the second conductive patterns 22B, each odd-numbered second conductive pattern 22B is connected to the corresponding odd-numbered second wire connection 40b, and each even-numbered second conductive pattern 22B is connected to the corresponding even-numbered second wire connection 40b. The second terminal wiring patterns 41b extend from the odd-numbered and even-numbered second wire connections 40b to the approximate center of one long side of the second conductive sheet 10B, and are each electrically connected to the corresponding the second terminal 116b. Thus, for example, the 1st and 2nd second terminal wiring patterns 41b have approximately the same lengths, and similarly the (2n-l)-th and (2n)-th second terminal wiring patterns 41b have approximately the same lengths (n = 1, 2, 3, ...).

Of course, the second terminals 116b may be formed in a corner of the second conductive sheet 10B or the vicinity thereof. However, in this case, as described above, the longest second terminal wiring pattern 41b and the second terminal wiring patterns 41b in the vicinity thereof are disadvantageously poor in the rate of transferring a signal to the corresponding second conductive pattern 22B. Thus, in this embodiment, the second terminals 116b are formed in the longitudinal center of the one long side of the second conductive sheet 10B, whereby the local signal transfer rate deterioration is prevented to increase the response speed.

The first terminal wiring patterns 41a may be arranged in the same manner as the above second terminal wiring patterns 41b, and the second terminal wiring patterns 41b may be arranged in the same manner as the above first terminal wiring patterns 41a.

In a case where the first laminated conductive sheet 50A is used in the touch panel, the protective layer is formed on the first conductive sheet 10A, and the first terminal wiring patterns 41a extending from a large number of the first conductive patterns 22A in the first conductive sheet 10A and the second terminal wiring patterns 41b extending from a large number of the second conductive patterns 22B in the second conductive sheet 10B are connected to a scan control circuit or the like.

A self or mutual capacitance technology can be preferably used for detecting a touch position. In the self capacitance technology, a voltage signal for the touch position detection is sequentially supplied to the first conductive patterns 22A, and further a voltage signal for the touch position detection is sequentially supplied to the second conductive patterns 22B. If a finger is brought into contact with or close to the upper surface of the protective layer 106, the capacitance between the first conductive pattern 22A and the second conductive pattern 22B corresponding to the touch position and the GND (ground) is increased, whereby signals from this first conductive pattern 22A and this second conductive pattern 22B have a waveform different from those of signals from the other conductive patterns. Thus, the touch position is calculated by the control circuit based on the signals transmitted from the first conductive pattern 22A and the second conductive pattern 22B. On the other hand, in the mutual capacitance technology, for example, a voltage signal for the touch position detection is sequentially supplied to the first conductive patterns 22A, and the second conductive patterns 22B are sequentially subjected to a sensing process (transmitted signal detection). If a finger is brought into contact with or close to the upper surface of the protective layer 106, the parallel stray capacitance of the finger is added to the parasitic capacitance between the first conductive pattern 22A and the second conductive pattern 22B corresponding to the touch position, whereby a signal from this second conductive pattern 22B has a waveform different from those of signals from the other second conductive patterns 22B. Thus, the touch position is calculated by the control circuit based on the order of the first conductive patterns 22A supplied with the voltage signal and the signal transmitted from the second conductive pattern 22B. Even if two fingers are brought into contact with or close to the upper surface of the protective layer 106 simultaneously, the touch positions can be detected by using the self or mutual capacitance technology. Conventional related detection circuits used in projected capacitive technologies are described in US Patent Nos. 4,582,955, 4,686,332, 4,733,222, 5,374,787, 5,543,588, and 7,030,860, US Patent Application Publication No. 2004/0155871, etc.

As shown in FIG. 6, among four sides of the second large lattice 14B in the second conductive pattern 22B, a fifth side 28e and a sixth side 28f are on one corner 26a not connected to the adjacent second large lattice 14B. The fifth side 28e is similar to the first side 28a of the first large lattice 14A in the first conductive sheet 10A, a continuous straight line 30 extends along the fifth side 28e, and a large number of needle-like lines 32 (sides of the small lattices 18) extend from the straight line 30 to form a comb-like shape. The sixth side 28f is similar to the third side 28c of the first large lattice 14A in the first conductive sheet 10A, and a continuous straight line 30 is formed along the sixth side 28f. Furthermore, a seventh side 28g and an eighth side 28h are on the other corner 26b not connected to the adjacent second large lattice 14B. The seventh side 26g is similar to the fifth side 28e, a continuous straight line 30 extends along the seventh side 28g, and a large number of needle-like lines 32 (sides of the small lattices 18) extend from the straight line 30 to form a comb-like shape. The eighth side 28h is similar to the sixth side 28f, and a continuous straight line 30 extends along the eighth side 28h.

In the second connection 16B, the four medium lattices 20 (a fifth medium lattice 20e to an eighth medium lattice 20h) are arranged in a zigzag manner, and each of the medium lattices 20 has a size equal to the total of four small lattices 18. The fifth medium lattice 20e is disposed between the 2nd straight line 30 along the sixth side 28f (the 2nd straight line 30 in the direction from the outside to the inside of the second large lattice 14B) and the straight line 30 of the eighth side 28h, and forms an L shaped space in combination with one small lattice 18. The sixth medium lattice 20f is disposed on one side of the fifth medium lattice 20e (the 2nd straight line 30 of the sixth side 28f), and forms such a square space that four small lattices 18 are arranged in a matrix and the central cross is removed. The seventh medium lattice 20g is adjacent to the fifth medium lattice 20e and the sixth medium lattice 20f, and has the same shape as the sixth medium lattice 20f. The eighth medium lattice 20h is disposed between the straight lines 30 of the seventh side 28g and the fifth side 28e, is adjacent to the sixth medium lattice 20f and the seventh medium lattice 20g, and forms an L-shaped space in combination with one small lattice 18 as in the fifth medium lattice 20e. One side of the eighth medium lattice 20h is disposed on an extended line of the straight line 30 along the eighth side 28h of the fifth medium lattice 20e. Also in the second conductive sheet 10B, if the small lattices 18 have an arrangement pitch Ps, the medium lattices 20 have an arrangement pitch Pm of 2 x Ps. In addition, the second connection 16B has a width Wc2 (which is a distance in the x direction between a vertex of the sixth medium lattice 20f and a vertex the seventh medium lattice 20g), and the width Wc2 satisfies the relation Wc2 > Ps/Vl. In this embodiment, the width Wc2 is 6 x (Ps/^2). For example, as shown in FIG. 7, in a case where the first conductive sheet 10A is stacked on the second conductive sheet 10B to form the first laminated conductive sheet 50A, the first connections 16A of the first conductive patterns 22A and the second connections 16B of the second conductive patterns 22B are arranged facing each other with the first transparent substrate 12A (see FIG. 5A) interposed therebetween, and the first insulations 24A of the first conductive patterns 22A and the second insulations 24B of the second conductive patterns 22B are arranged facing each other with the first transparent substrate 12A interposed therebetween. Though the first conductive patterns 22A and the second conductive patterns 22B have the same line width, they are exaggeratingly shown by thick lines and thin lines respectively to clearly represent the positions thereof in FIG. 7.

In a case where the stack of the first conductive sheet 10A and the second conductive sheet 10B is viewed from above, spaces between the first large lattices 14A in the first conductive sheet 10A are filled with the second large lattices 14B in the second conductive sheet 10B. Thus, the sensing region 112 is covered with the large lattices. In this case, the ends of the comb teeth 32 on the first sides 28a and the second sides 28b of the first large lattices 14A are connected to the straight lines 30 along the sixth sides 28f and the eighth sides 28h of the second large lattices 14B, to form an arrangement of the small lattices 18 as viewed from above. Similarly, the ends of the comb teeth 32 on the fifth sides 28e and the seventh sides 28g of the second large lattices 14B are connected to the straight lines 30 along the third sides 28c and the fourth sides 28d of the first large lattices 14A, to form an arrangement of the small lattices 18 as viewed from above. As a result, the boundaries between the first large lattices 14A and the second large lattices 14B cannot be easily found.

For example, in a case where all the sides of the first large lattices 14A and the second large lattices 14B are formed in the shapes of the straight lines 30 (i.e., where the open ends of the lines 32 extending from the first side 28a and the second side 28b of each first large lattice 14A are connected to form straight lines 30, and also the open ends of the lines 32 extending from the fifth side 28e and the seventh side 28g of each second large lattice 14B are connected to form straight lines 30), the overlaps of the straight lines 30 have large widths (thickened line shapes) due to slight deterioration of stack position accuracy, whereby the boundaries between the first large lattices 14A and the second large lattices 14B are highly visible to deteriorate the visibility disadvantageously. In contrast, in this embodiment, the ends of the comb teeth 32 overlap with the straight line 30 as described above, whereby the boundaries between the first large lattices 14A and the second large lattices 14B are made less visible to improve the visibility. Though an opening having a size equal to one medium lattice is formed in each overlap of the first insulation 24A and the second insulation 24B, the opening does not block a light and is less visible unlike the above thickened line. Particularly if the opening has the same size as the medium lattice, the opening is not significantly larger than the surrounding small lattices 18, and thereby is further less visible.

For example, in the case where all the first sides 28a to the eighth sides 28h of the first large lattices 14A and the second large lattices 14B are formed in the shapes of the straight lines 30, the straight lines 30 of the fifth to eighth sides 28e to 28h of the second large lattices 14B are positioned right under the straight lines 30 of the first to fourth sides 28a to 28d of the first large lattice 14A. In this case, all the straight lines 30 function as conductive portions, so that a parasitic capacitance is formed between the sides of the first large lattice 14A and the second large lattice 14B, and the parasitic capacitance acts as a noise on charge information to significantly deteriorate the S/N ratio. Furthermore, since the parasitic capacitance is formed between each pair of the first large lattice 14A and the second large lattice 14B, a large number of the parasitic capacitances are connected in parallel in the first conductive patterns 22A and the second conductive patterns 22B to increase the CR time constant. If the CR time constant is increased, there is a possibility that the waveform rise of the voltage signal supplied to the first conductive pattern 22A (and the second conductive pattern 22B) is retarded, and an electric field for the position detection is hardly generated under a predetermined scan time. In addition, there is a possibility that also the waveform rise or fall of the signal transmitted from each of the first conductive patterns 22A and the second conductive patterns 22B is retarded, and the waveform change of the transmitted signal cannot be detected under a predetermined scan time. This leads to detection accuracy deterioration and response speed deterioration. Thus, in this case, the detection accuracy and response speed can be improved only by reducing the number of the first large lattices 14A and the second large lattices 14B (lowering the resolution) or by reducing the size of the display screen, and the laminated conductive sheet cannot be used in a large screen such as a B5 sized, A4 sized, or larger screen.

In contrast, in this embodiment, as shown in FIG. 5A, the projected distance Lf between the straight lines 30 along the sides of the first large lattice 14A and the second large lattice 14B is approximately equal to the side length of the small lattice 18 (50 to 500 \xm). Furthermore, only the ends of the needle-like lines 32 extending from the first side 28a and the second side 28b of the first large lattice 14A overlap with the straight lines 30 along the sixth side 28f and the eighth side 28h of the second large lattice 14B, and only the ends of the needle-like lines 32 extending from the fifth side 28e and the seventh side 28g of the second large lattice 14B overlap with the straight lines 30 along the third side 28c and the fourth side 28d of the first large lattice 14A. Therefore, only a small parasitic capacitance is formed between the first large lattice 14A and the second large lattice 14B. As a result, the CR time constant can be reduced to improve the detection accuracy and the response speed.

It is preferred that the optimum value of the projected distance Lf is appropriately determined depending not on the sizes of the first large lattices 14A and the second large lattices 14B but on the sizes (the line widths and the side lengths) of the small lattices 18 in the first large lattices 14A and the second large lattices 14B. If the small lattices 18 have an excessively large size as compared with the sizes of the first large lattices 14A and the second large lattices 14B, the resultant conductive sheet may have a high light transmittance, but the dynamic range of the transmitted signal may be reduced to lower the detection sensitivity. On the other hand, if the small lattices 18 have an excessively small size, the resultant conductive sheet may have a high detection sensitivity, but the light transmittance may be deteriorated under the restriction of line width reduction.

If the small lattices 18 have a line width of 1 to 9 (xm, the optimum value of the projected distance Lf (the optimum distance) is preferably 100 to 400 \un, more preferably 200 to 300 jxm. In a case where the small lattices 18 have a smaller line width, the optimum distance can be further reduced. However, in this case, the electrical resistance is increased, so that the CR time constant may be increased even under a small parasitic capacitance to deteriorate the detection sensitivity and the response speed. Thus, the line width of the small lattice 18 is preferably within the above range.

For example, the sizes of the first large lattice 14A, the second large lattice 14B, and the small lattice 18 are determined based on the size of the display panel 110 or the size and touch position detection resolution (drive pulse period) of the sensing region 112, and the optimum distance between the first large lattice 14A and the second large lattice 14B is obtained based on the line width of the small lattice 18.

In a case where the overlap of the first connection 16A and the second connection 16B is viewed from above, the connection point of the fifth medium lattice 20e and the seventh medium lattice 20g in the second connection 16B is positioned approximately at the center of the second medium lattice 20b around the first large lattice 14A, the connection point of the sixth medium lattice 20f and the eighth medium lattice 20h in the second connection 16B is positioned approximately at the center of the third medium lattice 20c around the first large lattice 14A, and the first medium lattice 20a to the eighth medium lattice 20h form a plurality of the small lattices 18 in combination. Therefore, the small lattices 18 are formed by the combination of the first connections 16A and the second connections 16B in the overlaps thereof. Thus formed small lattices 18 cannot be distinguished from the surrounding small lattices 18 in the first large lattices 14A and the second large lattices 14B, so that the visibility is improved.

In this embodiment, in the terminal wiring region 114, a plurality of the first terminals 116a are formed in the longitudinal center of the periphery on the one long side of the first conductive sheet 10A, and a plurality of the second terminals 116b are formed in the longitudinal center of the periphery on the one long side of the second conductive sheet 10B. Particularly, in the example of FIG. 3, the first terminals 116a and the second terminals 116b do not overlap with each other but are close to each other, and the first terminal wiring patterns 41a and the second terminal wiring patterns 41b do not overlap with each other. For example, the first terminal 116a may partially overlap with the odd-numbered second terminal wiring pattern 41b.

Thus, the first terminals 116a and the second terminals 116b can be electrically connected to the control circuit by using a cable and two connectors (a connector for the first terminals 116a and a connector for the second terminals 116b) or one connector (a complex connector to be connected to the first terminals 116a and the second terminals 116b).

Since the first terminal wiring patterns 41a and the second terminal wiring patterns 41b do not vertically overlap with each other, a parasitic capacitance generation is reduced therebetween to prevent the response speed deterioration.

Since the first wire connections 40a are arranged along the one long side of the sensing region 112 and the second wire connections 40b are arranged along both the short sides of the sensing region 112, the area of the terminal wiring region 114 can be reduced. Therefore, the size of the display panel 110 containing the touch panel 100 can be easily reduced, and the display screen 110a can be made to seem larger. Also the operability of the touch panel 100 can be improved.

The area of the terminal wiring region 114 may be further reduced by reducing the distance between the adjacent first terminal wiring patterns 41a or the adjacent second terminal wiring patterns 41b. The distance is preferably 10 to 50 μm in view of preventing migration.

Alternatively, the area of the terminal wiring region 114 may be reduced by arranging the second terminal wiring pattern 41b between the adjacent first terminal wiring patterns 41a as viewed from above. However, if the pattern is misaligned, the first terminal wiring pattern 41a may vertically overlap with the second terminal wiring pattern 41b to increase the parasitic capacitance therebetween. This leads to the response speed deterioration. Thus, in the case of using such an arrangement, the distance between the adjacent first terminal wiring patterns 41a is preferably 50 to 100 μm.

Consequently, in a case where the first laminated conductive sheet 50A is used in the projected capacitive touch panel 100 or the like, the response speed and the size of the touch panel 100 can be easily increased. Furthermore, the boundaries between the first large lattices 14A of the first conductive sheet 10A and the second large lattices 14B of the second conductive sheet 10B can be made less visible. In addition, the first connections 16A and the second connections 16B are combined to form a plurality of the small lattices 18, whereby defects such as the local line thickening can be prevented, and the overall visibility can be improved.

Furthermore, the CR time constant of a large number of the first conductive patterns 22A and the second conductive patterns 22B can be significantly reduced, whereby the response speed can be increased, and the position detection can be readily carried out in an operation time (a scan time). Thus, the screen sizes (not the thickness but the length and width) of the touch panel 100 can be easily increased.

As shown in FIGS. 4 and 5A, in the above first laminated conductive sheet 50A, the first conductive patterns 22A are formed on one main surface of the first transparent substrate 12A, and the second conductive patterns 22B are formed on one main surface of the second transparent substrate 12B. Alternatively, as shown in FIG. 5B, the first conductive patterns 22A may be formed on one main surface of the first transparent substrate 12A, and the second conductive patterns 22B may be formed on the other main surface of the first transparent substrate 12A. In this case, the second transparent substrate 12B is not used, the first transparent substrate 12A is stacked on the second conductive part 13B, and the first conductive part 13A is stacked on the first transparent substrate 12A. In addition, another layer may be disposed between the first conductive sheet 10A and the second conductive sheet 10B. The first conductive patterns 22A and the second conductive patterns 22B may be arranged facing each other as long as they are insulated.

Three structures shown schematically in FIGS. 8A to 8C can be preferably used in this embodiment.

In a first structure example shown in FIG. 8A, the first laminated conductive sheet 50A shown in FIG. 5B (containing the first conductive part 13A, the first transparent substrate 12A, and the second conductive part 13B) is stacked on the display device 108 with a transparent adhesive 120 interposed therebetween, a hard coat layer 122 is stacked on the first laminated conductive sheet 50A, and further an antireflection layer 124 is stacked on the hard coat layer 122. The transparent adhesive 120, the second conductive part 13B, the first transparent substrate 12A, and the first conductive part 13A for the touch panel 100 on the display device 108, and the hard coat layer 122 and the antireflection layer 124 form an antireflection film 126 on the touch panel 100.

In a second structure example shown in FIG. 8B, the first laminated conductive sheet 50A shown in FIG. 5B and a protective resin layer 128 are stacked on the display device 108 with the transparent adhesive 120 interposed therebetween, the hard coat layer 122 is stacked on the protective resin layer 128, and further the antireflection layer 124 is stacked on the hard coat layer 122. The transparent adhesive 120, the second conductive part 13B, the first transparent substrate 12A, the first conductive part 13A, and the protective resin layer 128 form the touch panel 100 on the display device 108, and the hard coat layer 122 and the antireflection layer 124 form the antireflection film 126 on the touch panel 100.

In a third structure example shown in FIG. 8C, the first laminated conductive sheet 50A shown in FIG. 5B and a second transparent adhesive 120B are stacked on the display device 108 with a first transparent adhesive 120A interposed therebetween, a transparent film 130 is stacked on the second transparent adhesive 120B, the hard coat layer 122 is stacked on the transparent film 130, and further the antireflection layer 124 is stacked on the hard coat layer 122. The first transparent adhesive 120A, the second conductive part 13B, the first transparent substrate 12A, the first conductive part 13A, and the second transparent adhesive 120B form the touch panel 100 on the display device 108, and the transparent film 130, the hard coat layer 122, and the antireflection layer 124 form the antireflection film 126 on the touch panel 100.

As shown in FIG. 3, first alignment marks 118a and second alignment marks 118b are preferably formed, for example on the corners of the first conductive sheet 10A and the second conductive sheet 10B. The first alignment marks 118a and the second alignment marks 118b are used for positioning the first conductive sheet 10A and the second conductive sheet 10B in a bonding process. If the first conductive sheet 10A and the second conductive sheet 10B are bonded to obtain the first laminated conductive sheet 50A, composite alignment marks are formed by the first alignment marks 118a and the second alignment marks 118b. The composite alignment marks can be used for positioning the first laminated conductive sheet 50A in the process of attaching to the display panel 110.

A touch panel conductive sheet according to a second embodiment (hereinafter referred to as a second laminated conductive sheet 50B) will be described below with reference to FIGS. 9 to 12.

As shown in FIG. 9, the second laminated conductive sheet 50B has approximately the same structure as the above first laminated conductive sheet 50A, but is different in that two or more rectangles are arranged to form a rectangular wave shape on each of the first sides 28a to the fourth sides 28d of the first large lattices 14A as shown in FIG. 10 and that two or more rectangles are arranged to form a rectangular wave shape on each of the fifth sides 28e to the eighth sides 28h of the second large lattices 14B as shown in FIG. 11.

Specifically, as shown in FIG. 10, the first large lattice 14A in the second laminated conductive sheet 50B is such that each alternate comb tooth 32 on the first side 28a and the second side 28b of the first large lattice 14A in the first conductive sheet 10A shown in FIG. 1 is connected to the next comb tooth 32 to form the small lattice 18 and each straight line 30 on the third side 28c and the fourth visibility is improved.

Though not shown in the drawings, the arrangement of the first wire connections 40a and the second wire connections 40b, the arrangement of the first terminal wiring patterns 41a and the second terminal wiring patterns 41b in the terminal wiring region 114, and the arrangement of the first terminals 116a and the second terminals 116b in the second laminated conductive sheet 50B are equal to those in the first laminated conductive sheet 50A.

Thus, also in a case where the second laminated conductive sheet 50B is used in the projected capacitive touch panel 100 or the like, the response speed and the size of the touch panel 100 can be easily increased. Furthermore, the boundaries between the first large lattices 14A of the first conductive sheet 10A and the second large lattices 14B of the second conductive sheet 10B are less visible, and the first connections 16A and the second connections 16B are combined to form the small lattices 18, so that defects such as the local line thickening can be prevented, and the overall visibility can be improved.

Particularly in the second laminated conductive sheet 50B, the four sides (the first side 28a to the fourth side 28d) of the first large lattice 14A and the four sides (the fifth side 28e to the eighth side 28h) of the second large lattice 14B have the equivalent rectangular wave shapes, whereby charge localization in the edges of the first large lattices 14A and the second large lattices 14B can be reduced to prevent false finger position detection.

Also in the second laminated conductive sheet 50B, as shown in FIG. 5A, the projected distance Lf between the straight lines 30 along the sides of the first large lattice 14A and the second large lattice 14B is approximately equal to the side length of the small lattice 18 (50 to 500 μm). Furthermore, only the rectangle corners in the rectangular wave shapes on the sides of the first large lattice 14A overlap with the rectangle corners in the rectangular wave shapes on the sides of the second large lattice 14B, whereby only a small parasitic capacitance is formed between the first large lattice 14A and the second large lattice 14B. As a result, also the CR time constant can be reduced to improve the detection accuracy and the response speed.

A modified example of the second laminated conductive sheet 50B will be described below with reference to FIGS. 13 and 14.

As shown in FIG. 13, a first conductive sheet lOAa in a laminated conductive sheet 50Ba according to the modified example has approximately the same structure as the above first conductive sheet 10A in the second laminated conductive sheet 50B (see FIG. 10), but is different in that the first connections 16A is formed not in a lattice shape but in an approximately Z line shape (a zigzag line shape). The first connection 16A is disposed between the intersection of the straight lines 30 along the second side 28b and the fourth side 28d of the first large lattice 14A and the intersection of the straight lines 30 along the first side 28a and the third side 28c of the first large lattice 14A.

Similarly, as shown in FIG. 14, a second conductive sheet 10Ba in the laminated conductive sheet 50Ba has approximately the same structure as the above second conductive sheet 10B in the second laminated conductive sheet 50B (see FIG. 11), but is different in that the second connection 16B is formed not in a lattice shape but in an approximately Z line shape (a zigzag line shape). The second connection 16B is disposed between the intersection of the straight lines 30 along the sixth side 28f and the eighth side 28h of the second large lattice 14B and the intersection of the straight lines 30 along the fifth side 28e and the seventh side 28g of the second large lattice 14B.

The width Wcl of the first connection 16A (the distance in the y direction between the bend points) satisfies the relation Wcl > Ps/√2. The width Wcl is 2 x (Ps/√2) in this example. Similarly, the width Wc2 of the second connection 16B (the distance in the x direction between the bend points) satisfies the relation Wc2 > Ps/√2. The width Wc2 is 2 x (Ps/√2) in this example.

In a case where the laminated conductive sheet 50Ba of the modified example is used in the projected capacitive touch panel or the like, the response speed and the size of the touch panel can be easily increased.

In the first conductive sheet 10A (lOAa) and the second conductive sheet 10B (lOBa), if the widths of the first connection 16A and the second connection 16B are excessively large, it may be difficult to arrange the large lattices 14, resulting in poor appearance. Therefore, the upper limits of the widths are preferably 2 x (Ps/√2) to 20 x (Ps/v^2), more preferably 8 x (Ps/√2) to 14 x (Ps/√2).

In the first conductive sheet 10A (lOAa) and the second conductive sheet 10B (lOBa), also the sizes of the small lattices 18 (including the side length and the diagonal line length), the number of the small lattices 18 in the first large lattice 14A, and the number of the small lattices 18 in the second large lattice 14B may be appropriately selected depending on the size and the resolution (the line number) of the touch panel.

Though the arrangement pitch Pm of the medium lattices 20 in the first connections 16A and the second connections 16B is twice larger than the arrangement pitch Ps of the small lattices 18 in the above first conductive sheet 10A (10Aa) and second conductive sheet 10B (10Ba), it may be appropriately selected depending on the number of the medium lattices 20. For example, the arrangement pitch Pm may be 1.5 or 3 times larger than the arrangement pitch Ps. If the arrangement pitch Pm of the medium lattices 20 is excessively small or large, it may be difficult to arrange the first large lattices 14A and the second large lattices 14B, resulting in poor appearance. Thus, the arrangement pitch Pm of the medium lattices 20 is preferably 1 to 10 times, more preferably 1 to 5 times, larger than the arrangement pitch Ps of the small lattices 18.

Also the sizes of the small lattices 18 (including the side length and the diagonal line length), the number of the small lattices 18 in the first large lattice 14A, and the number of the small lattices 18 in the second large lattice 14B may be appropriately selected depending on the size and the resolution (the line number) of the touch panel.

Though the first conductive sheet 10A (10Aa) and the second conductive sheet 10B (10Ba) are used in the projected capacitive touch panel 100 in the above examples, it is to be understood that they can be used in a surface capacitive touch panel or a resistive touch panel.

The first conductive sheet 10A (10Aa) and the second conductive sheet 10B (10Ba) may be produced in the following manner. For example, a photosensitive material having the first transparent substrate 12A or the second transparent substrate 12B and thereon a photosensitive silver halide-containing emulsion layer is exposed and developed, whereby metallic silver portions and light-transmitting portions are formed in the exposed areas and the unexposed areas respectively to obtain the first conductive patterns 22A and the second conductive patterns 22B. The metallic silver portions may be subjected to a physical development treatment and/or a plating treatment to deposit a conductive metal thereon.

As shown in FIG. 5B, the first conductive patterns 22A may be formed on one main surface of the first transparent substrate 12A, and the second conductive patterns 22B may be formed on the other main surface thereof. In this case, if the one main surface is exposed and then the other main surface is exposed in the usual method, the first conductive patterns 22A and the second conductive patterns 22B often cannot be obtained with desired structures. In particular, it is difficult to uniformly form the patterns containing the comb teeth 32 or the rectangular wave shapes on the sides of the first large lattices 14A and the second large lattices 14B.

Therefore, the following production method can be preferably used.

Thus, the first conductive patterns 22A on the one main surface and the second conductive patterns 22B on the other main surface are formed by subjecting photosensitive silver halide emulsion layers formed on either side of the first transparent substrate 12A to one-shot exposure.

A specific example of the production method will be described below with reference to FIGS. 15 to 17.

First, in the step SI of FIG. 15, a long photosensitive material 140 is prepared. As shown in FIG. 16A, the photosensitive material 140 has the first transparent substrate 12A, a photosensitive silver halide emulsion layer (hereinafter referred to as a first photosensitive layer 142a) formed on one main surface of the first transparent substrate 12A, and a photosensitive silver halide emulsion layer (hereinafter referred to as a second photosensitive layer 142b) formed on the other main surface of the first transparent substrate 12A.

In the step S2 of FIG. 15, the photosensitive material 140 is exposed. In this step, a simultaneous both-side exposure is carried out, the exposure including a first exposure treatment for irradiating the first photosensitive layer 142a on the first transparent substrate 12A with a light in a first exposure pattern and a second exposure treatment for irradiating the second photosensitive layer 142b on the first transparent substrate 12A with a light in a second exposure pattern. In the example of FIG. 16B, the first photosensitive layer 142a is irradiated through a first photomask 146a with a first light 144a (a parallel light) and the second photosensitive layer 142b is irradiated through a second photomask 146b with a second light 144b (a parallel light) while conveying the long photosensitive material 140 in one direction. The first light 144a is such that a light from a first light source 148a is converted to the parallel light by an intermediate first collimator lens 150a, and the second light 144b is such that a light from a second light source 148b is converted to the parallel light by an intermediate second collimator lens 150b. Though the two light sources (the first light source 148a and the second light source 148b) are used in the example of FIG. 16B, only one light source may be used. In this case, a light from the one light source may be divided by an optical system into the first light 144a and the second light 144b for exposing the first photosensitive layer 142a and the second photosensitive layer 142b.

In the step S3 of FIG. 15, the exposed photosensitive material 140 is developed to produce the first laminated conductive sheet 50A shown in FIG. 5B. The first laminated conductive sheet 50A has the first transparent substrate 12A, the first conductive part 13A (including the first conductive patterns 22A) formed in the first exposure pattern on the one main surface of the first transparent substrate 12A, and the second conductive part 13B (including the second conductive patterns 22B) formed in the second exposure pattern on the other main surface of the first transparent substrate 12A. Preferred exposure time and development time for the first photosensitive layer 142a and the second photosensitive layer 142b depend on the types of the first light source 148a, the second light source 148b, and a developer, etc., and cannot be categorically determined. The exposure time and development time may be selected in view of achieving a development ratio of 100%.

As shown in FIG. 17, in the first exposure treatment in the production method of this embodiment, for example, the first photomask 146a is placed in close contact with the first photosensitive layer 142a, the first light source 148a is arranged facing the first photomask 146a, and the first light 144a is emitted from the first light source 148a toward the first photomask 146a, so that the first photosensitive layer 142a is exposed. The first photomask 146a has a glass substrate composed of a transparent soda glass and a mask pattern (a first exposure pattern 152a) formed thereon. Therefore, in the first exposure treatment, areas in the first photosensitive layer 142a, corresponding to the first exposure pattern 152a in the first photomask 146a, are exposed. A space of approximately 2 to 10 (im may be formed between the first photosensitive layer 142a and the first photomask 146a.

Similarly, in the second exposure treatment, for example, the second photomask 146b is placed in close contact with the second photosensitive layer 142b, the second light source 148b is arranged facing the second photomask 146b. and the second light 144b is emitted from the second light source 148b toward the second photomask 146b, so that the second photosensitive layer 142b is exposed. The second photomask 146b, as well as the first photomask 146a, has a glass substrate composed of a transparent soda glass and a mask pattern (a second exposure pattern 152b) formed thereon. Therefore, in the second exposure treatment, areas in the second photosensitive layer 142b, corresponding to the second exposure pattern 152b in the second photomask 146b, are exposed. In this case, a space of approximately 2 to 10 μm may be formed between the second photosensitive layer 142b and the second photomask 146b.

In the first and second exposure treatments, the emission of the first light 144a from the first light source 148a and the emission of the second light 144b from the second light source 148b may be carried out simultaneously or independently. If the emissions are simultaneously carried out, the first photosensitive layer 142a and the second photosensitive layer 142b can be simultaneously exposed in one exposure process to reduce the treatment time.

In a case where both of the first photosensitive layer 142a and the second photosensitive layer 142b are not spectrally sensitized, a light incident on one side may affect the image formation on the other side (the back side) in the both-side exposure of the photosensitive material 140.

Thus, the first light 144a from the first light source 148a reaches the first photosensitive layer 142a and is scattered by silver halide particles in the first photosensitive layer 142a, and a part of the scattered light is transmitted through the first transparent substrate 12A and reaches the second photosensitive layer 142b. Then, a large area of the boundary between the second photosensitive layer 142b and the first transparent substrate 12A is exposed to form a latent image. As a result, the second photosensitive layer 142b is exposed to the second light 144b from the second light source 148b and the first light 144a from the first light source 148a. If the second photosensitive layer 142b is developed to prepare the first laminated conductive sheet 50A, the conductive pattern corresponding to the second exposure pattern 152b (the second conductive part 13B) is formed, and additionally a thin conductive layer is formed due to the first light 144a from the first light source 148a between the conductive patterns, so that the desired pattern (corresponding to the second exposure pattern 152b) cannot be obtained. This is true also for the first photosensitive layer 142a.

As a result of intense research in view of solving this problem, it has been found that if the thicknesses and the applied silver amounts of the first photosensitive layer 142a and the second photosensitive layer 142b are selected within particular ranges, the incident light can be absorbed by the silver halide to suppress the light transmission to the back side. In this embodiment, the thicknesses of the first photosensitive layer 142a and the second photosensitive layer 142b may be 1 to 4 μm. The upper limit is preferably 2.5 μm. The applied silver amounts of the first photosensitive layer 142a and the second photosensitive layer 142b may be 5 to 20 g/m2.

In the above-described contact both-side exposure technology, the exposure may be inhibited by dust or the like attached to the film surface to generate an image defect. It is known that the dust attachment can be prevented by applying a conductive substance such as a metal oxide or a conductive polymer to the film. However, the metal oxide or the like remains in the processed product to deteriorate the transparency of the final product, and the conductive polymer is disadvantageous in storage stability, etc. As a result of intense research, it has been found that a silver halide layer with reduced binder content exhibits a satisfactory conductivity for static charge prevention. Thus, the volume ratio of silver/binder is limited in the first photosensitive layer 142a and the second photosensitive layer 142b. The silver/binder volume ratios of the first photosensitive layer 142a and the second photosensitive layer 142b are 1/1 or more, preferably 2/1 or more.

In a case where the thicknesses, the applied silver amounts, and the silver/binder volume ratios of the first photosensitive layer 142a and the second photosensitive layer 142b are selected as described above, the first light 144a emitted from the first light source 148a to the first photosensitive layer 142a does not reach the second photosensitive layer 142b as shown in FIG. 17. Similarly, the second light 144b emitted from the second light source 148b to the second photosensitive layer 142b does not reach the first photosensitive layer 142a. As a result, in the following development for producing the first laminated conductive sheet 50A, as shown in FIG. 5B, only the conductive pattern corresponding to the first exposure pattern 152a (the pattern of the first conductive part 13A) is formed on the one main surface of the first transparent substrate 12A, and only the conductive pattern corresponding to the second exposure pattern 152b (the pattern of the second conductive part 13B) is formed on the other main surface of the first transparent substrate 12A, so that the desired patterns can be obtained.

In the production method using the above one-shot both-side exposure, the first photosensitive layer 142a and the second photosensitive layer 142b can have both of the satisfactory conductivity and both-side exposure suitability, and the same or different patterns can be formed on each side of the first transparent substrate 12A by the exposure, whereby the electrodes of the touch panel 100 can be easily formed, and the touch panel 100 can be made thinner (smaller).

In the above production method, the first conductive patterns 22A and the second conductive patterns 22B are formed using the photosensitive silver halide emulsion layer. The other examples of the production methods include the following methods.

A photoresist film disposed on a copper foil on each of the first transparent substrate 12A and the second transparent substrate 12B may be exposed and developed to form a resist pattern, and the unmasked copper foil from the resist pattern may be etched to obtain the first conductive patterns 22A and the second conductive patterns 22B.

Alternatively, a paste containing fine metal particles may be printed on each of the first transparent substrate 12A and the second transparent substrate 12B, and the printed paste may be plated with a metal to obtain the first conductive patterns 22A and the second conductive patterns 22B.

The first conductive patterns 22A and the second conductive patterns 22B may be printed on the first transparent substrate 12A and the second transparent substrate 12B by using a screen or gravure printing plate.

The first conductive patterns 22A and the second conductive patterns 22B may be formed on the first transparent substrate 12A and the second transparent substrate 12B by using an Inkjet method.

A particularly preferred method, which contains using a photographic photosensitive silver halide material for producing the first conductive sheet 10A (10Aa) and the second conductive sheet 10B (10Ba) according to this embodiment, will be mainly described below.

The method for producing the first conductive sheet 10A (10Aa) and the second conductive sheet 10B (10Ba) of this embodiment includes the following three processes different in the photosensitive materials and development treatments.

(1) A process comprising subjecting a photosensitive black-and-white silver halide material free of physical development nuclei to a chemical or thermal development to form the metallic silver portions on the material.

(2) A process comprising subjecting a photosensitive black-and-white silver halide material having a silver halide emulsion layer containing physical development nuclei to a solution physical development to form the metallic silver portions on the material.

(3) A process comprising subjecting a stack of a photosensitive black-and-white silver halide material free of physical development nuclei and an image-receiving sheet having a non-photosensitive layer containing physical development nuclei to a diffusion transfer development to form the metallic silver portions on the non-photosensitive image-receiving sheet.

In the process of (1), an integral black-and-white development procedure is used to form a transmittable conductive film such as a light-transmitting conductive film on the photosensitive material. The resulting silver is a chemically or thermally developed silver containing a high-specific surface area filament, and thereby shows a high activity in the following plating or physical development treatment.

In the process of (2). the silver halide particles are melted around and deposited on the physical development nuclei in the exposed areas to form a transmittable conductive film such as a light-transmitting conductive film on the photosensitive material. Also in this process, an integral black-and-white development procedure is used. Though high activity can be achieved since the silver halide is deposited on the physical development nuclei in the development, the developed silver has a spherical shape with small specific surface area.

In the process of (3), the silver halide particles are melted in the unexposed areas, and are diffused and deposited on the development nuclei of the image-receiving sheet, to form a transmittable conductive film such as a light-transmitting conductive film on the sheet. In this process, a so-called separate-type procedure is used, and the image-receiving sheet is peeled off from the photosensitive material.

A negative or reversal development treatment can be used in the processes. In the diffusion transfer development, the negative development treatment can be carried out using an auto-positive photosensitive material.

The chemical development, thermal development, solution physical development, and diffusion transfer development have the meanings generally known in the art, and are explained in common photographic chemistry texts such as Shin-ichi Kikuchi, "Shashin Kagaku (Photographic Chemistry)", Kyoritsu Shuppan Co., Ltd., 1955 and C. E. K. Mees, "The Theory of Photographic Processes, 4th ed.", Mcmillan, 1977. A liquid treatment is generally used in the present invention, and also a thermal development treatment may be utilized. For example, techniques described in Japanese Laid-Open Patent Publication Nos. 2004-184693, 2004-334077, and 2005-010752 and Japanese Patent Application Nos. 2004-244080 and 2004-085655 can be used in the present invention.

The structure of each layer in the first conductive sheet 10A (10Aa) and the second conductive sheet 10B (10Ba) of this embodiment will be described in detail below. [First transparent substrate 12A and second transparent substrate 12B]
The first transparent substrate 12A and the second transparent substrate 12B may be a plastic film, a plastic plate, a glass plate, etc.

Examples of materials for the plastic film and the plastic plate include polyesters such as polyethylene terephthalates (PET) and polyethylene naphthalates (PEN); polyolefins such as polyethylenes (PE), polypropylenes (PP), polystyrenes, and EVA; vinyl resins; polycarbonates (PC); polyamides; polyimides; acrylic resins; and triacetyl celluloses (TAC).

The first transparent substrate 12A and the second transparent substrate 12B are preferably a film or plate of a plastic having a melting point of about 290°C or lower, such as PET (melting point 258°C), PEN (melting point 269°C), PE (melting point 135°C). PP (melting point 163°C), polystyrene (melting point 230°C), polyvinyl chloride (melting point 180°C), polyvinylidene chloride (melting point 212°C), or TAC (melting point 290°C). The PET is particularly preferred from the viewpoints of light transmittance, workability, etc. The conductive film such as the first conductive sheet 10A (10Aa) and the second conductive sheet 10B (10Ba) used in the first laminated conductive sheet 50A and the second laminated conductive sheet 50B (50Ba) is required to be transparent, and therefore the first transparent substrate 12A and the second transparent substrate 12B preferably have a high transparency. [Silver salt emulsion layer]

The silver salt emulsion layer to be converted to a conductive layer in the first conductive sheet 10A (10Aa) and the second conductive sheet 10B (10Ba) (a conductive portion such as the first large lattice 14A, the first connection 16A, the second large lattice 14B, the second connection 16B, or the small lattice 18) contains a silver salt and a binder and may further contain a solvent and an additive such as a dye.

The silver salt used in this embodiment may be an inorganic silver salt such as a silver halide or an organic silver salt such as silver acetate. In this embodiment, the silver halide is preferred because of its excellent light sensing property.

The applied silver amount (the amount of the applied silver salt in the silver density) of the silver salt emulsion layer is preferably 1 to 30 g/m2, more preferably 1 to 25 g/m2, further preferably 5 to 20 g/m2. In a case where the applied silver amount is within this range, the resultant first laminated conductive sheet 50A or second laminated conductive sheet 50B (50Ba) can exhibit a desired surface resistance.

Examples of the binders used in this embodiment include gelatins, polyvinyl alcohols (PVA), polyvinyl pyrolidones (PVP), polysaccharides such as starches, celluloses and derivatives thereof, polyethylene oxides, polyvinylamines, chitosans, polylysines, polyacrylic acids, polyalginic acids, polyhyaluronic acids, and carboxycelluloses. The binders show a neutral, anionic, or cationic property depending on the ionicity of the functional group.

In this embodiment, the amount of the binder in a silver salt emulsion layer 16 is not particularly limited, and may be appropriately selected to obtain sufficient dispersion and adhesion properties. The volume ratio of silver/binder in the silver salt emulsion layer 16 is preferably 1/4 or more, more preferably 1/2 or more. Furthermore, the silver/binder volume ratio is preferably 100/1 or less, more preferably 50/1 or less. Particularly, the silver/binder volume ratio is further preferably 1/1 to 4/1, most preferably 1/1 to 3/1. In a case where the silver/binder volume ratio of the silver salt emulsion layer is within the range, the resistance variation can be reduced even under various applied silver amount, whereby the first laminated conductive sheet 50A and the second laminated conductive sheet 50B can be produced with a uniform surface resistance. The silver/binder volume ratio can be obtained by converting the silver halide/binder weight ratio of the material to the silver/binder weight ratio, and by further converting the silver/binder weight ratio to the silver/binder volume ratio.

The solvent used for forming the silver salt emulsion layer is not particularly limited, and examples thereof include water, organic solvents (e.g. alcohols such as methanol, ketones such as acetone, amides such as formamide, sulfoxides such as dimethyl sulfoxide, esters such as ethyl acetate, ethers), ionic liquids, and mixtures thereof.

In this embodiment, the ratio of the solvent to the total of the silver salt, the binder, and the like in the silver salt emulsion layer is 30% to 90% by mass, preferably 50% to 80% by mass.

The additive used in this embodiment is not particularly limited, and may be preferably selected from known additives. [Other layers]

A protective layer (not shown) may be formed on the silver salt emulsion layer. The protective layer used in this embodiment contains a binder such as a gelatin or a high-molecular polymer, and is disposed on the photosensitive silver salt emulsion layer to improve the scratch prevention or mechanical property. The thickness of the protective layer is preferably 0.5 μm or less. The method of applying or forming the protective layer is not particularly limited, and may be appropriately selected from known applying or forming methods. In addition, an undercoat layer or the like may be formed below the silver salt emulsion layer 16.

The steps for producing the first conductive sheet 10A (10Aa) and the second conductive sheet 10B (10Ba) will be described below. [Exposure]

In this embodiment, the first conductive patterns 22A and the second conductive patterns 22B may be formed in a printing process, and may be formed by exposure and development treatments, etc. in another process. Thus, a photosensitive material having the first transparent substrate 12A or the second transparent substrate 12B and thereon the silver salt-containing layer or a photosensitive material coated with a photopolymer for photolithography is subjected to the exposure treatment. An electromagnetic wave may be used in the exposure. For example, the electromagnetic wave may be a light such as a visible light or an ultraviolet light, or a radiation ray such as an X-ray. The exposure may be carried out using a light source having a wavelength distribution or a specific wavelength.
[Development treatment]

In this embodiment, the emulsion layer is subjected to the development treatment after the exposure. Common development treatment technologies for photographic silver salt films, photographic papers, print engraving films, emulsion masks for photomasking, and the like may be used in the present invention. The developer used in the development treatment is not particularly limited, and may be a PQ developer, an MQ developer, an MAA developer, etc.

Examples of commercially available developers usable in the present invention include CN-16, CR-56, CP45X, FD-3, and PAPITOL available from FUJIFILM Corporation, C-41, E-6, RA-4, D-19, and D-72 available from Eastman Kodak Company, and developers contained in kits thereof. The developer may be a lith developer.

In the present invention, the development process may include a fixation treatment for removing the silver salt in the unexposed areas to stabilize the material. Fixation treatment technologies for photographic silver salt films, photographic papers, print engraving films, emulsion masks for photomasking, and the like may be used in the present invention.

In the fixation treatment, the fixation temperature is preferably about 20°C to 50°C, more preferably 25°C to 45°C. The fixation time is preferably 5 seconds to 1 minute, more preferably 7 to 50 seconds. The amount of the fixer is preferably 600 ml/m2 or less, more preferably 500 ml/m2 or less, particularly preferably 300 ml/m2 or less, per 1 m2 of the photosensitive material treated.

The developed and fixed photosensitive material is preferably subjected to a water washing treatment or a stabilization treatment. The amount of water used in the water washing or stabilization treatment is generally 20 L or less, and may be 3 L or less, per 1 m2 of the photosensitive material. The water amount may be 0, and thus the photosensitive material may be washed with storage water.

The ratio of the metallic silver contained in the exposed areas after the development to the silver contained in the areas before the exposure is preferably 50% or more, more preferably 80% or more by mass. If the ratio is 50% or more by mass, a high conductivity can be achieved.

In this embodiment, the tone (gradation) obtained by the development is preferably more than 4.0, though not particularly restrictive. In a case where the tone is more than 4.0 after the development, the conductivity of the conductive metal portion can be increased while maintaining the high transmittance of the light-transmitting portion. For example, the tone of 4.0 or more can be obtained by doping with rhodium or iridium ion.

The conductive sheet is obtained by the above steps. The surface resistance of the resultant conductive sheet is preferably within the range of 0.1 to 100 ohm/sq. The lower limit is preferably 1 ohm/sq or more, 3 ohm/sq or more, 5 ohm/sq or more, or 10 ohm/sq. The upper limit is preferably 70 ohm/sq or less or 50 ohm/sq or less. The conductive sheet may be subjected to a calender treatment after the development treatment to obtain a desired surface resistance. [Physical development treatment and plating treatment]

In this embodiment, to increase the conductivity of the metallic silver portion formed by the above exposure and development treatments, conductive metal particles may be deposited thereon by a physical development treatment and/or a plating treatment. In the present invention, the conductive metal particles may be deposited on the metallic silver portion by only one of the physical development and plating treatments or by the combination of the treatments. The metallic silver portion, subjected to the physical development treatment and/or the plating treatment in this manner, is also referred to as the conductive metal portion.

In this embodiment, the physical development is such a process that metal ions such as silver ions are reduced by a reducing agent, whereby metal particles are deposited on a metal or metal compound core. Such physical development has been used in the fields of instant B & W film, instant slide film, printing plate production, etc., and the technologies can be used in the present invention.

The physical development may be carried out at the same time as the above development treatment after the exposure, and may be carried out after the development treatment separately.

In this embodiment, the plating treatment may contain electroless plating (such as chemical reduction plating or displacement plating), electrolytic plating, or a combination thereof. Known electroless plating technologies for printed circuit boards, etc. may be used in this embodiment. The electroless plating is preferably electroless copper plating. [Oxidation treatment]

In this embodiment, the metallic silver portion formed by the development treatment or the conductive metal portion formed by the physical development treatment and/or the plating treatment is preferably subjected to an oxidation treatment. For example, by the oxidation treatment, a small amount of a metal deposited on the light-transmitting portion can be removed, so that the transmittance of the light-transmitting portion can be increased to approximately 100%.

[Conductive metal portion]

In this embodiment, the lower limit of the line width of the conductive metal portion (the first conductive part 13A and the second conductive part 13B) is preferably 1 pun or more, 3 pm or more, 4 {JII or more, or 5 (un or more, and the upper limit thereof is preferably 10 [aa or less, 9 [im or less, or 8 (jm or less. If the line width is less than the lower limit, the conductive metal portion has an insufficient conductivity, whereby the touch panel 100 using the conductive part has an insufficient detection sensitivity. On the other hand, if the line width is more than the upper limit, moire is significantly generated due to the conductive metal portion, and the touch panel 100 using the conductive part has a poor visibility. In a case where the line width is within the above range, the moire of the conductive metal portion is improved, and the visibility is remarkably improved. The line distance (the distance between the sides facing each other in the small lattice 18) is preferably 30 to 500 μm, more preferably 50 to 400 μm, most preferably 100 to 350 μm. The conductive metal portion may have a part with a line width of more than 200 μm for the purpose of ground connection, etc.

In this embodiment, the opening ratio of the conductive metal portion is preferably 85% or more, more preferably 90% or more, most preferably 95% or more, in view of the visible light transmittance. The opening ratio is the ratio of the light-transmitting portions other than the conductive portions including the first large lattices 14A, the first connections 16A, the second large lattices 14B, the second connections 16B, and the small lattices 18 to the whole.

For example, a square lattice having a line width of 15 μm and a pitch of 300 μm has an opening ratio of 90%. [Light-transmitting portion]

In this embodiment, the light-transmitting portion is a portion having light transmittance, other than the conductive metal portions in the first conductive sheet 10A and the second conductive sheet 10B. The transmittance of the light-transmitting portion, which is herein a minimum transmittance value in a wavelength region of 380 to 780 nm obtained neglecting the light absorption and reflection of the first transparent substrate 12A and the second transparent substrate 12B, is 90% or more, preferably 95% or more, more preferably 97% or more, further preferably 98% or more, most preferably 99% or more.

The exposure is preferably carried out using a glass mask method or a laser lithography pattern exposure method. [First conductive sheet 10A (10Aa) and second conductive sheet 10B (10Ba)]

In the first conductive sheet 10A (10Aa) and the second conductive sheet 10B (10Ba) of this embodiment, the thicknesses of the first transparent substrate 12A and the second transparent substrate 12B are preferably 5 to 350 μm, more preferably 30 to 150 μm. In a case where the thicknesses are 5 to 350 μm, a desired visible light transmittance can be obtained, and the substrates can be easily handled.

The thickness of the metallic silver portion formed on the first transparent substrate 12A or the second transparent substrate 12B may be appropriately selected by controlling the thickness of the coating liquid for the silver salt-containing layer applied to the substrate. The thickness of the metallic silver portion may be selected within a range of 0.001 to 0.2 mm, and is preferably 30 μm or less, more preferably 20 μm or less, further preferably 0.01 to 9 μm, most preferably 0.05 to 5 μm The metallic silver portion is preferably formed in a patterned shape. The metallic silver portion may have a monolayer structure or a multilayer structure containing two or more layers. In a case where the metallic silver portion has a patterned multilayer structure containing two or more layers, the layers may have different wavelength color sensitivities. In this case, different patterns can be formed in the layers by using exposure lights with different wavelengths.

In a touch panel, the conductive metal portion preferably has a smaller thickness. As the thickness is reduced, the viewing angle and visibility of the display panel are improved. Thus, the thickness of the layer of the conductive metal deposited on the conductive metal portion is preferably less than 9 μm, more preferably 0.1 μm or more but less than 5 μm, further preferably 0.1 μm or more but less than 3 (μm.

In this embodiment, the thickness of the metallic silver portion can be controlled by changing the coating thickness of the silver salt-containing layer, and the thickness of the conductive metal particle layer can be controlled in the physical development treatment and/or the plating treatment, whereby the first conductive sheet 10A (10Aa) and the second conductive sheet 10B (10Ba) can be easily produced with a thickness of less than 5 μm (preferably less than 3 μm) .

The plating or the like is not necessarily carried out in the method for producing the first conductive sheet 10A (10Aa) and the second conductive sheet 10B (10Ba) of this embodiment. This is because the desired surface resistance can be obtained by controlling the applied silver amount and the silver/binder volume ratio of the silver salt emulsion layer in the method. The calender treatment or the like may be carried out if necessary. (Film hardening treatment after development treatment)

It is preferred that after the silver salt emulsion layer is developed, the resultant is immersed in a hardener and thus subjected to a film hardening treatment. Examples of the hardeners include boric acid and dialdehydes such as 2,3-dihydroxy-l,4-dioxane, glutaraldehyde and adipaldehyde, described in Japanese Laid-Open Patent Publication No. 02-141279. [Laminated conductive sheet]

The antireflection film 126 may be attached to the laminated conductive sheet. In this case, a structure according to the above first to third structure examples of FIGS. 8A to 8C can be preferably used.

For example, the antireflection film 126 is prepared by forming the hard coat layer 122 and the antireflection layer 124 on the first laminated conductive sheet 50A (see the first and second structure examples) or by forming the transparent film 130, the hard coat layer 122, and the antireflection layer 124 on the first laminated conductive sheet 50A (see the third structure example).

A preferred embodiment of the antireflection film 126 will be described below mainly with respect to the third structure example.

The transparent film 130 is used on the viewer side of the display device 108, and therefore has to be a colorless film having a high light transmittance and an excellent transparency. The transparent film 130 is preferably a plastic film. Examples of polymers for the plastic film include cellulose acylates (e.g., cellulose triacetates such as TAC-TD80U and TD80UF available from FUJIFILM Corporation, cellulose diacetates, cellulose acetate propionates, cellulose acetate butylates), polyamides, polycarbonates, polyesters (e.g., polyethylene terephthalates, polyethylene naphthalates), polystyrenes, polyolefins, norbornene resins (e.g., ARTON (trade name) available from JSR Corporation), amorphous polyolefins (e.g., ZEONEX (trade name) available from Zeon Corporation), and (meth)acrylic resins (e.g., ACRYPET VRL20A (trade name) available from Mitsubishi Rayon Co., Ltd., ring structure-containing acrylic resins described in Japanese Laid-Open Patent Publication Nos. 2004-070296 and 2006-171464). Among the polymers, the cellulose triacetates, cellulose acetate propionates, cellulose acetate butylates, polyethylene terephthalates, and polyethylene naphthalates are preferred, and the cellulose triacetates are particularly preferred.

The hard coat layer 122 is preferably formed in the antireflection film 126 to improve the physical strength. The hard coat layer 122 may contain two or more layers stacked.

The refractive index of the hard coat layer 122 is preferably 1.48 to 1.90, more preferably 1.50 to 1.80, further preferably 1.52 to 1.65, in view of optical design for achieving the antireflection property. In this embodiment, at least one low refractive index layer is disposed on the hard coat layer 122. Therefore, if the refractive index of the hard coat layer 122 is lower than the above range, the antireflection property tends to be deteriorated. On the other hand, if the refractive index is higher than the above range, the color of the reflected light tends to be heightened.

The thickness of the hard coat layer 122 is generally about 0.5 to 50 μm, preferably 1 to 20 μm, more preferably 2 to 15 μm, most preferably 3 to 10 μm, in view of sufficiently improving the durability and impact resistance of the antireflection film 126. The strength of the hard coat layer 122 is preferably 2H or more, more preferably 3H or more, most preferably 4H or more, in a pencil hardness test. Furthermore, a sample of the hard coat layer 122 preferably exhibits a smaller wear amount in a Taber test in accordance with JIS K 5400.

The hard coat layer 122 is preferably formed by a crosslinking or polymerization reaction of an ionizing radiation-curable compound. For example, the hard coat layer 122 may be formed by applying a composition containing an ionizing radiation-curable multifunctional monomer or oligomer to the transparent film 130 and by crosslinking or polymerizing the multifunctional monomer or oligomer. A functional group of the ionizing radiation-curable multifunctional monomer or oligomer is preferably a photo-, electron beam-, or radiation-polymerizable group. particularly a photo-polymerizable group. The photo-polymerizable group may be an unsaturated group such as a (meth)acryloyl group, a vinyl group, a styryl group, or an allyl group, etc., and the (meth)acryloyl group is most preferable. Specifically, the compound may be a monomer described in Paragraphs [0087] and [0088] of Japanese Laid-Open Patent Publication No. 2006-030740, which may be hardened by a method described in Paragraph [0089] of this document. A photopolymerization initiator described in Paragraphs [0090] to [0093] of this document may be used in the photopolymerization.

The hard coat layer 122 may contain matting particles such as inorganic compound particles or resin particles having an average particle diameter of 1.0 to 10.0 urn (preferably 1.5 to 7.0 [Am) to obtain an internal scattering property. The matting particles may be selected from those described in Paragraph [0114] of Japanese Laid-Open Patent Publication No. 2006-030740.

A binder of the hard coat layer 122 may contain a high refractive index monomer, fine inorganic particles (having a primary particle diameter of 10 to 200 nm not to cause light scattering), or both thereof to control the refractive index of the hard coat layer 122. The fine inorganic particles have an effect of reducing the cure shrinkage due to the crosslinking reaction in addition to the effect of controlling the refractive index. The fine inorganic particles may be composed of a compound described as an inorganic filler in Paragraph [0120] of Japanese Laid-Open Patent Publication No. 2006-030740.

The antireflection film 126 contains the above hard coat layer 122 and the antireflection layer 124 formed thereon, and may contain the transparent film 130 as an underlayer. The antireflection layer 124 preferably has a refractive index and an optical thickness in the following manner to utilize an optical interference. The antireflection film 126 may contain only one antireflection layer 124, and may contain a stack of a plurality of the antireflection layers 124 to obtain a lower reflectance. In the case of using the stack of a plurality of the antireflection layers 124, optical interference layers having different refractive indices may be alternately stacked, and two or more optical interference layers having different refractive indices may be stacked. Specifically, the antireflection film 126 preferably has such a structure that only a low refractive index layer is formed on the hard coat layer 122, that a high refractive index layer and a low refractive index layer are formed in this order on the hard coat layer 122, or that a middle refractive index layer, a high refractive index layer, and a low refractive index layer are formed in this order on the hard coat layer 122. It should be noted that the terms "low", "middle", and "high" of the refractive index layers represent relative magnitude relations of the refractive indices. The refractive index of the low refractive index layer is preferably lower than that of the hard coat layer 122. If the refractive index difference between the low refractive index layer and the hard coat layer 122 is excessively small, the antireflection property tends to be deteriorated. If the refractive index difference is excessively large, the color of the reflected light tends to be heightened. The refractive index difference between the low refractive index layer and the hard coat layer 122 is preferably 0.01 to 0.40, more preferably 0.05 to 0.30.

The refractive index and the thickness of each layer preferably satisfy the following conditions.

The refractive index of the low refractive index layer is preferably 1.20 to 1.46, more preferably 1.25 to 1.42, particularly preferably 1.30 to 1.38. The thickness of the low refractive index layer is preferably 50 to 150 nm, more preferably 70 to 120 nm.

In a case where the low refractive index layer is stacked on the high refractive index layer to prepare the antireflection film 126, the refractive index of the high refractive index layer is preferably 1.55 to 2.40, more preferably 1.60 to 2.20, further preferably 1.65 to 2.10, most preferably 1.80 to 2.00.

In a case where the middle refractive index layer, the high refractive index layer, and the low refractive index layer are stacked in this order on the transparent film 130 (or the touch panel 100) to prepare the antireflection film 126, the refractive index of the high refractive index layer is preferably 1.65 to 2.40, further preferably 1.70 to 2.20. The refractive index of the middle refractive index layer is controlled to an intermediate value between the refractive indices of the low and high refractive index layers. The refractive index of the middle refractive index layer is preferably 1.55 to 1.80. The high and middle refractive index layers may have optical thicknesses selected depending on the refractive indices.

[Low refractive index layer]

The low refractive index layer is preferably hardened after the layer formation. The haze of the low refractive index layer is preferably 3% or less, more preferably 2% or less, most preferably 1% or less.

The low refractive index layer according to the embodiment of the present invention is preferably formed from a composition containing at least (1) a fluorine-containing polymer having a crosslinkable or polymerizable functional group, (2) a hydrolytic condensation product of a fluorine-containing organosilane material as a main component, or (3) a monomer having two or more ethylenic unsaturated groups and a fine inorganic particle having a hollow structure.

(1) Fluorine-containing compound having crosslinkable or polymerizable functional group

The fluorine-containing compound having the crosslinkable or polymerizable functional group may be a copolymer of a fluorine-containing monomer and a monomer having the crosslinkable or polymerizable functional group.

Specifically, the fluorine-containing compound may be a copolymer having a main chain of only carbon atoms and containing a polymerization unit of a fluorine-containing vinyl monomer and a polymerization unit having a (meth)acryloyl group in a side chain, and examples of such copolymers include P-l to P-40 described in Paragraphs [0043] to [0047] of Japanese Laid-Open Patent Publication No. 2004-045462. The fluorine-containing compound may be a fluorine-containing polymer having a silicone component for improving the abrasion resistance and lubricity, such as a graft polymer containing a fluorine atom in a main chain and containing a polymerization unit having a polysiloxane moiety in a side chain, and examples of such graft polymers include compounds described in Tables 1 and 2 in Paragraphs [0074] to [0076] of Japanese Laid-Open Patent Publication No. 2003-222702. Furthermore, the fluorine-containing compound may be an ethylenic unsaturated group-containing fluoropolymer containing a structural unit derived from a polysiloxane compound in a main chain, and examples of such fluoropolymers include compounds described in Japanese Laid-Open Patent Publication No. 2003-183322.

A hardener having a polymerizable unsaturated group may be appropriately used in combination with the above polymer as described in Japanese Laid-Open Patent Publication No. 2000-017028. Also a multifunctional fluorine-containing compound having a polymerizable unsaturated group may be preferably used in combination with the above polymer as described in Japanese Laid-Open Patent Publication No. 2002-145952. Examples of such multifunctional compounds having the polymerizable unsaturated group include the above-described monomers having two or more ethylenic unsaturated groups. Furthermore, also a hydrolytic condensation product of an organosilane (particularly an organosilane having a (meth)acryloyl group) described in Japanese Laid-Open Patent Publication No. 2004-170901 may be preferably used. In a case where the above polymer has the polymerizable unsaturated group, the compounds are particularly preferably used in combination with the polymer to exhibit a large effect of improving the abrasion resistance.

If the polymer per se does not have a satisfactory hardening property alone, a crosslinkable compound may be added thereto to obtain the satisfactory hardening property. For example, in a case where the polymer has a hydroxyl group, an amino compound may be preferably used as a hardener. The amino compound used as the crosslinkable compound may be a compound having one or both of a hydroxyalkylamino group and an alkoxyalkylamino group, the number of the groups in the compound being two or more in total. Specific examples of such compounds include melamine compounds, urea compounds, benzoguanamine compounds, and glycoluril compounds. The compound is preferably hardened with an organic acid or a salt thereof.

(2) Hydrolytic condensation product of fluorine-containing organosilane material

Also the composition containing the hydrolytic condensation product of the fluorine-containing organosilane compound as a main component is preferred because of its low refractive index and high coating surface hardness. The hydrolytic condensation product is preferably a condensation product of a tetraalkoxysilane and a compound having a hydrolyzable silanol group in one or both ends of a fluorinated alkyl group. Specific examples of such compositions are described in Japanese Laid-Open Patent Publication Nos. 2002-265866 and 2002-317152.

(3) Composition containing monomer having two or more ethylenic unsaturated groups and fine inorganic particle having a hollow structure

In another preferred example, the low refractive index layer contains a low refractive index particle and a binder. The low refractive index particle may be an organic or inorganic particle, and is preferably a particle having an internal cavity. Specific examples of such hollow particles include silica-based particles described in Japanese Laid-Open Patent Publication No. 2002-079616 (see, e.g.. Paragraphs [0041] to [0049]). The refractive index of the particle is preferably 1.15 to 1.40, further preferably 1.20 to 1.30. The binder may be the monomer having two or more ethylenic unsaturated groups described above with respect to the hard coat layer 122.

The polymerization initiator described above with respect to the hard coat layer 122 is preferably added to the low refractive index layer (see, e.g.. Paragraphs [0090] to [0093] of Japanese Laid-Open Patent Publication No. 2006-030740). In the case of using a radical-polymerizable compound, 1 to 10 parts by mass (preferably 1 to 5 parts by mass) of the polymerization initiator may be used per 100 parts by mass of the compound.

An inorganic particle may jointly be used in the low refractive index layer. The particle diameter of the fine particle may be 15% to 150% of the thickness of the low refractive index layer to improve the abrasion resistance. The particle diameter is preferably 30% to 100% and further preferably 45% to 60% of the thickness.

A known polysiloxane- or fluorine-based antifouling agent, lubricant, or the like may be appropriately added to the low refractive index layer to improve the antifouling property, water resistance, chemical resistance, lubricity, etc. [High refractive index layer/middle refractive index layer]

As described above, in the antireflection film 126, the high refractive index layer may be disposed between the low refractive index layer and the hard coat layer 122 to improve the antireflection property.

The high and middle refractive index layers are preferably formed from a hardenable composition containing a fine inorganic high refractive index particle and a binder. The above-described fine inorganic high refractive index particle for increasing the refractive index of the hard coat layer 122 may be used in the hardenable composition. Preferred examples of the fine inorganic high refractive index particles include inorganic compound particles (such as silica particles and Ti02 particles) and resin particles (such as acrylic particles, crosslinked acrylic particles, polystyrene particles, crosslinked styrene particles, melamine resin particles, and benzoguanamine resin particles).

The high and middle refractive index layers may be preferably formed in the following manner. The inorganic particle is dispersed in a dispersion medium to prepare a dispersion liquid, and a binder precursor (such as an ionizing radiation-curable multifunctional monomer or oligomer to be hereinafter described), a photopolymerization initiator, and the like for forming a matrix are added thereto if necessary, to prepare a coating composition for the high and middle refractive index layers. Then, the coating composition for the high and middle refractive index layers is applied to the transparent film or the like, and the applied composition is hardened by crosslinking or polymerizing the ionizing radiation-curable compound (such as the multifunctional monomer or oligomer).

It is preferred that the binder of the high and middle refractive index layers is further crosslinked or polymerized with a dispersing agent in or after the process of applying the layer.

For example, the above preferred dispersing agent and the ionizing radiation-curable multifunctional or oligomer are crosslinked or polymerized, whereby an anionic group of the dispersing agent is introduced to the binder in the high and middle refractive index layers. The anionic group acts to maintain the dispersion state of the inorganic particle in the binder in the high and middle refractive index layers, and the binder exhibits a film forming ability due to the crosslinked or polymerized structure, whereby the high and middle refractive index layers containing the inorganic particle are improved in the physical strength, chemical resistance, and weather resistance.

The ratio of the binder in the high refractive index layer to the solid content of the coating composition for the layer is 5% to 80% by mass.

The ratio of the inorganic particle in the high refractive index layer to the layer is preferably 10% to 90% by mass, more preferably 15% to 80% by mass, particularly preferably 15% to 75% by mass. Two or more types of the inorganic particles may be used in combination in the high refractive index layer.

In the case of disposing the low refractive index layer on the high refractive index layer, the refractive index of the high refractive index layer is preferably higher than that of the transparent film 130.

In the case of using the high refractive index layer as an optical interference layer, the thickness thereof is preferably 30 to 200 nm, more preferably 50 to 170 nm, particularly preferably 60 to 150 nm.

The high and middle refractive index layers preferably have a lower haze. The haze is preferably 5% or less, further preferably 3% or less, particularly preferably 1% or less.

The integrated reflectance of the antireflection film 126 having the low refractive index layer is preferably 3.0% or less, further preferably 2.0% or less, most preferably 0.3% to 1.5%.

The surface free energy of the low refractive index layer is preferably reduced to improve the antifouling property. Specifically, it is preferred that a fluorine- or polysiloxane structure-containing compound is used in the low refractive index layer. Alternatively, a separate antifouling layer containing the compound may be formed on the low refractive index layer.

Preferred examples of the polysiloxane structure-containing additives include reactive group-containing polysiloxanes such as KF-100T, X-22-169AS, KF-102. X-22-3701IE, X-22-164B, X-22-5002, X-22-173B, X-22-174D, X-22-167B, and X-22-161AS (trade names) available from Shin-Etsu Chemical Co., Ltd.; AK-5, AK-30, and AK-32 (trade names) available from Toagosei Co., Ltd.; and SILAPLANE FM0725 and SILAPLANE FM0721 (trade names) available from Chisso Corporation. Furthermore, silicone compounds described in Tables 2 and 3 of Japanese Laid-Open Patent Publication No. 2003-112383 may be preferably used as the additive. The ratio of the polysiloxane additive to the total solid content of the low refractive index layer is preferably 0.1% to 10% by mass, particularly preferably 1% to 5% by mass.
[Formation of antireflection film 126]
The antireflection film 126 may be formed by the following coating method though the formation is not limited thereto. (Preparation for coating)

First, a coating liquid containing the component for forming each layer such as the hard coat layer 122 and the antireflection layer 124 is prepared. In general, the coating liquid contains an organic solvent, whereby it is necessary that the water content of the liquid is controlled to 2% or less, and that the liquid is sealed to reduce the volatilization of the solvent. The organic solvent is selected depending on the material for each layer. A stirrer or a disperser is appropriately used for improving the homogeneity of the coating liquid.

The prepared coating liquid is preferably filtrated before the application to prevent application failure. A filter used in the filtration preferably has a smaller pore diameter as long as the component in the coating liquid is not removed. The filtration pressure is appropriately selected within a range of 1.5 MPa or less. The filtrated coating liquid is preferably subjected to an ultrasonic dispersion treatment immediately before the application to defoam the dispersion liquid and to maintain the dispersion state.

Before the application, the transparent film 130 may be subjected to a heat treatment for correcting a base deformation or a surface treatment for improving an application property or adhesion to the coating layer. Specific examples of the surface treatments include corona discharge treatments, glow discharge treatments, flame treatments, acid treatments, alkali treatments, and ultraviolet irradiation treatments. An undercoat layer may be preferably formed as described in Japanese Laid-Open Patent Publication No. 07-333433.

A dust removal process is preferably carried out before the application. The process may be performed using a dust removal method described in Paragraph [0119] of Japanese Laid-Open Patent Publication No. 2010-032795. It is particularly preferred that the static electricity on the transparent film 130 is removed before the dust removal process in view of increasing the dust removal efficiency and preventing attachment of wastes. The electricity removal may be performed using a method described in Paragraph [0120] of Japanese Laid-Open Patent Publication No. 2010-032795. Furthermore, a method described in Paragraphs [0121] and [0123] of this document may be utilized to improve the flatness and adhesion of the transparent film 130. (Application process)

Each layer in the antireflection film 126 may be formed by the following application method though the formation is not limited thereto. A known application method may be used in the formation, and examples thereof include dip coating methods, air knife coating methods, curtain coating methods, roller coating methods, wire bar coating methods, gravure coating methods, extrusion coating methods (die coating methods) (see US Patent No. 2681294 and International Patent Publication No. WO 05/123274), and microgravure coating methods. Among the methods, the microgravure coating methods and the die coating methods are preferred. The microgravure coating method is described in Paragraphs [0125] and [0126] of Japanese Laid-Open Patent Publication No. 2010-032795, the die coating method is described in Paragraphs [0127] and [0128] of this document, and the methods can be used in this embodiment. It is preferred that the die coating method is carried out at a coating rate of 20 m/minute or more from the viewpoint of productivity. (Drying process)

After the coating liquid is applied onto the transparent film 130 for the antireflection film 126 directly or with another layer interposed, the resultant web is preferably conveyed to a heat zone to remove the solvent.

The solvent may be removed by utilizing various drying techniques, and specific examples thereof include those described in Japanese Laid-Open Patent Publication Nos. 2001-286817, 2001-314798, 2003-126768, 2003-315505, and 2004-034002, etc.

The drying process may be carried out in the drying zone under a temperature condition described in Paragraph [0130] of Japanese Laid-Open Patent Publication No. 2010-032795 and a drying air condition described in Paragraph [0131] of this document. (Hardening process)

After or at a later stage of the drying process for removing the solvent, each coating layer for the antireflection film 126 may be conveyed in the web state in a zone for hardening the coating layer under an ionizing radiation and/or heat. The ionizing radiation is not particularly limited and may be appropriately selected from ultraviolet, electron beam, near-ultraviolet, visible, near-infrared, infrared, and X-ray radiations, etc. depending on the type of the hardenable composition forming the coating layer. The ionizing radiation is preferably the ultraviolet or electron beam radiation, and is particularly preferably the ultraviolet radiation that can be easily handled and can readily emit a high energy.

An ultraviolet source for photopolymerizing an ultraviolet-hardening compound described in Paragraph [0133] of Japanese Laid-Open Patent Publication No. 2010-032795 and an electron beam described in Paragraph [0134] of this document may be used in this embodiment. Furthermore, an irradiation condition, an irradiation light intensity, and an irradiation time described in Paragraphs [0135] and [0138] of this document may be used in this embodiment. In addition, film surface temperatures before and after the irradiation, an oxygen concentration, and a method for controlling the oxygen concentration described in Paragraphs [0136], [0137], and [0139] to [0144] of this document may be used in this embodiment. (Handling for continuous production)

The antireflection film 126 may be continuously produced by the steps of continuously feeding the transparent film 130 from the roll, applying and drying the coating liquid, hardening the applied coating, and rewinding the transparent film 130 having the hardened layer.

The steps may be carried out in each layer formation. Alternatively, a plurality of application zones, drying chambers, and hardening zones may be formed in a so-called tandem structure, whereby a plurality of the layers may be successively formed.

In the production of the antireflection film 126, it is preferred that the fine filtration of the coating liquid, the application process in the application zone, and the drying process in the drying chamber are carried out in a highly clean air atmosphere, and wastes and dusts on the transparent film 130 are sufficiently removed before the application. The air cleanliness in the application and drying processes is preferably Class 10 (the number of particles having a size of 0.5 μm or more being 353 or less per m3) or higher, further preferably Class 1 (the number being 35.5 or less per m3) or higher, in accordance with US Federal Standard 209E. It is preferred that also the processes other than the application and drying processes (such as the feeding and rewinding processes) are carried out under the high air cleanliness.

In view of improving the image sharpness, it is preferred that the surface flatness and smoothness of the antireflection film 126 are maximally increased, and in addition the sharpness of a transmitted image is controlled. The transmitted image sharpness of the antireflection film 126 is preferably 60% or more. In general, the transmitted image sharpness is a reference index indicating a blur level of an image transmitted through a film. As the film has a larger value of the transmitted image sharpness, the image transmitted through the film is sharper and better. The transmitted image sharpness is preferably 70% or more, further preferably 80% or more.

The antireflection film 126 may be used as a viewer-side surface film on the display device 108. The display devices 108 include various liquid crystal displays, plasma displays, organic EL displays, and touch panels. Depending on the characteristics of the outermost surface of the display device 108 on which the antireflection film 126 is disposed, before the antireflection film 126 is attached to the touch panel 100, an adhesive layer may be formed on the back surface of the transparent film 130 (on which the coating layers are not formed), and the back surface of the transparent film 130 may be saponified.

A technique described in Paragraphs [0149] to [0160] of Japanese Laid-Open Patent Publication No. 2010-032795 may be used for saponifying the back surface of the transparent film 130.

The present invention may be appropriately combined with technologies described in the following patent publications and international patent pamphlets shown in Tables 1 and 2. The terms "Japanese Laid-Open Patent", "Publication No.", "Pamphlet No.", etc. are omitted.

Examples

The present invention will be described more specifically below with reference to Examples. Materials, amounts, ratios, treatment contents, treatment procedures, and the like, used in Examples, may be appropriately changed without departing from the scope of the invention. The following specific examples are therefore to be considered in all respects as illustrative and not restrictive.

The surface resistance and the transmittance of each conductive sheet according to Examples 1 to 6 and

Comparative Examples 1 and 2 were measured, and the moire and the visibility were evaluated. The components, measurement results, and evaluation results of Examples 1 to 6 and Comparative Examples 1 and 2 are shown in Table 3. (Photosensitive silver halide material)

An emulsion containing an aqueous medium, a gelatin, and silver iodobromochloride particles was prepared. The amount of the gelatin was 10.0 g per 150 g of Ag, and the silver iodobromochloride particles had an I content of 0.2 mol%, a Br content of 40 mol%, and an average spherical equivalent diameter of 0.1 μm.

K3Rh2Br9 and K2IrCl6 were added to the emulsion at a concentration of 10"7 mol/mol-silver to dope the silver bromide particles with Rh and Ir ions. Na2PdCl4 was further added to the emulsion, and the resultant emulsion was subjected to gold-sulfur sensitization using chlorauric acid and sodium thiosulfate. The emulsion and a gelatin hardener were applied to the first transparent substrate 12A and the second transparent substrate 12B composed of a polyethylene terephthalate (PET). The applied silver amount was 10 g/m2, and the Ag/gelatin volume ratio was 2/1.

The PET support had a width of 30 cm, and the emulsion was applied thereto into a width of 25 cm and a length of 20 m. Both the edge portions having a width of 3 cm were cut off to obtain a roll of a photosensitive silver halide material having a width of 24 cm. (Exposure)

An A4 (210 mm x 297 mm) sized region of the first transparent substrate 12A was exposed in the pattern of the first conductive sheet 10A shown in FIGS. 1 and 4, and an A4 sized region of the second transparent substrate 12B was exposed in the pattern of the second conductive sheet 10B shown in FIGS. 4 and 6. The exposure was carried out using a parallel light from a light source of a high-pressure mercury lamp and photomasks having the above patterns.

(Development treatment)
Formulation of 1 L of developer
Hydroquinone 20 g
Sodium sulfite 50 g
Potassium carbonate 40 g
Ethylenediaminetetraacetic acid 2 g
Potassium bromide 3 g
Polyethylene glycol 2000 1 g
Potassium hydroxide 4 g
pH Controlled at 10.3
Formulation of 1 L of fixer
Ammonium thiosulfate solution (75%) 300 ml
Ammonium sulfite monohydrate 25 g
1,3-Diaminopropanetetraacetic acid 8 g
Acetic acid 5 g
Aqueous ammonia (27%) 1 g
pH Controlled at 6.2

The exposed photosensitive material was treated with the above treatment agents under the following treatment conditions using an automatic processor FG-710PTS manufactured by FUJIFILM Corporation. In this process, a development treatment was carried out at 35°C for 30 seconds, a fixation treatment was carried out at 34°C for 23 seconds, and then a water washing treatment was carried out for 20 seconds at a water flow rate of 5 L/min. (Example 1)

The conductive portions on the first conductive sheet 10A and the second conductive sheet 10B (the first conductive patterns 22A and the second conductive patterns 22B) had a line width of 1 μm, the small lattices 18 had a side length of 50 μm, and the large lattices (the first large lattices 14A and the second large lattices 14B) had a side length of 3 mm. (Example 2)

First and second conductive sheets of Example 2 were produced in the same manner as Example 1 except that the conductive portions had a line width of 5 μm and the small lattices 18 had a side length of 50 μm. (Example 3)
First and second conductive sheets of Example 3 were produced in the same manner as Example 1 except that the conductive portions had a line width of 9 μm, the small lattices 18 had a side length of 150 μm, and the large lattices had a side length of 5 mm. (Example 4)

First and second conductive sheets of Example 4 were produced in the same manner as Example 1 except that the conductive portions had a line width of 10 μm, the small lattices 18 had a side length of 300 μm, and the large lattices had a side length of 6 mm. (Example 5)

First and second conductive sheets of Example 5 were produced in the same manner as Example 1 except that the conductive portions had a line width of 15 μm, the small lattices 18 had a side length of 400 μm, and the large lattices had a side length of 10 mm. (Example 6)

First and second conductive sheets of Example 6 were produced in the same manner as Example 1 except that the conductive portions had a line width of 20 μm, the small lattices 18 had a side length of 500 μm, and the large lattices had a side length of 10 mm. (Comparative Example 1)

First and second conductive sheets of Comparative Example 1 were produced in the same manner as Example 1 except that the conductive portions had a line width of 0.5 \xm, the small lattices 18 had a side length of 40 \im, and the large lattices had a side length of 3 mm. (Comparative Example 2)

First and second conductive sheets of Comparative Example 3 were produced in the same manner as Comparative Example 1 except that the conductive portions had a line width of 25 μm, the small lattices 18 had a side length of 500 μm, and the large lattices had a side length of 10 mm. (Surface resistance measurement)

In each of the first conductive sheet 10A and the second conductive sheet 10B, the surface resistivity values of optionally selected 10 areas were measured by LORESTA GP (Model No. MCP-T610) manufactured by Dia Instruments Co., Ltd. utilizing an in-line four-probe method (ASP), and the average of the measured values was obtained to evaluate the detection accuracy. (Transmittance measurement)

The transmittance of each of the first conductive sheet 10A and the second conductive sheet 10B was measured by a spectrophotometer to evaluate the transparency. (Moire evaluation)

In each of Examples 1 to 6 and Comparative Examples 1 and 2, the first conductive sheet 10A was stacked on the second conductive sheet 10B to obtain a laminated conductive sheet. The laminated conductive sheet was attached to a display screen of a liquid crystal display device to obtain a touch panel. The touch panel was fixed to a turntable, and the liquid crystal display device was operated to display a white color. The moire of the laminated conductive sheet was visually observed and evaluated while turning the turntable within a bias angle range of -45° to +45°.

The moire was observed at a distance of 1.5m from the display screen of the liquid crystal display device. The laminated conductive sheet was evaluated as "Excellent" when the moire was not visible, as "Fair" when the moire was slightly visible to an acceptable extent, or as "Poor" when the moire was highly visible. (Visibility evaluation)

In a case where the touch panel was fixed to the turntable and the liquid crystal display device was operated to display the white color, before the moire evaluation, whether a thickened line or a black point was formed or not on the touch panel and whether boundaries between the first large lattices 14A and the second large lattices 14B in the touch panel were visible or not were observed by the naked eye.

As is clear from Table 3, in Comparative Example 1, though the moire and the visibility were both excellent, the surface resistance was 1 kohm/sq or more to lower the conductivity, so that the touch panel may exhibit an insufficient detection sensitivity. In Comparative Example 2, though the conductivity and the transmittance were both excellent, the moire was highly visible and the conductive portions per se could be seen by the naked eye to deteriorate the visibility.

In contrast, among Examples 1 to 6, in Examples 1 to 5, all the conductivity, transmittance, moire, and visibility were excellent. Example 6 was inferior to Examples 1 to 5 in the moire and visibility evaluations. However, in Example 6, the moire was only slightly visible to an acceptable extent, and it was not difficult to observe the image on the display device.

It is to be understood that the conductive sheet, the conductive sheet using method, and the capacitive touch panel of the present invention are not limited to the above embodiments, and various changes and modifications may be made therein without departing from the scope of the invention.

CLAIMS

Claim 1. A conductive sheet comprising
a substrate (12A) and
a conductive part (13A) formed on the substrate (12A), wherein the conductive part (13A) contains two or more conductive large lattices (14A) composed of a thin metal wire and a connection (16A) composed of a thin metal wire for electrically connecting the adjacent large lattices (14A), the large lattices (14A) each contain a combination of two or more small lattices (18), the large lattices (14A) are combined to form a circuit, and the connection (16A) has a width Wc, the small lattices (18) have a pitch Ps, and the width Wc and the pitch Ps satisfy the relation Wc > Ps/V2.

Claim 2. The conductive sheet according to claim 1, wherein two or more of the large lattices (14A) are arranged in a first direction with the connection (16A) disposed therebetween to form a conductive pattern (22A), two or more of the conductive patterns (22A) are arranged in a second direction perpendicular to the first direction, an electrically isolated insulation (24A) not containing the small lattices (18) is disposed between the adjacent conductive patterns (22A), and the conductive patterns (22A) and the insulation (24A) are arranged to form the circuit.

Claim 3. The conductive sheet according to claim 1, wherein the large lattices (14A) have a side length of 3 to 10 mm.

Claim 4. The conductive sheet according to claim 1, wherein the small lattices (18) have a side length of 30 to 500 fxm.

Claim 5. The conductive sheet according to claim 1, wherein sides facing each other in the small lattices (18) are disposed at a distance of 30 to 500 \xm.

Claim 6. The conductive sheet according to claim 1, wherein the thin metal wire has a line width of 10 m or less.

Claim 7. A conductive sheet comprising a substrate (12A),
a first conductive part (13A) formed on one main surface of the substrate (12A), and
a second conductive part (13B) formed on the other main surface of the substrate (12A), wherein the first conductive part (13A) contains two or more conductive first large lattices (14A) composed of a thin metal wire and a first connection (16A) composed of a thin metal wire for electrically connecting the adjacent first large lattices (14A), the second conductive part (13B) contains two or more conductive second large lattices (14B) composed of a thin metal wire and a second connection (16B) composed of a thin metal wire for electrically connecting the adjacent second large lattices (14B), the first large lattices (14A) and the second large lattices (14B) each contain a combination of two or more small lattices (18), the first large lattices (14A) are arranged in a first direction with the first connection (16A) disposed therebetween to form a first conductive pattern (22A), the first large lattices (14A) and the second large lattices (14B) are combined to form a circuit, and the first connection (16A) has a width Wcl, the second connection (16B) has a width Wc2, the small lattices (18) have a pitch Ps, and the width Wcl, the width Wc2, and the pitch Ps satisfy the relations Wcl > Ps/V2, and Wc2 > Ps/^2.

Claim 8. The conductive sheet according to claim 7, wherein the first large lattices (14A) are arranged in the first direction with the first connection (16A) disposed therebetween to form the first conductive pattern (22A) composed of the thin metal wire, two or more of the second large lattices (14B) are arranged in a second direction perpendicular to the first direction with the second connection (16B) disposed therebetween to form a second conductive pattern (22B) composed of the thin metal wire, an electrically isolated first insulation (24A) not containing the small lattices (18) is disposed between the adjacent first conductive patterns (22A), an electrically isolated second insulation (24B) not containing the small lattices (18) is disposed between the adjacent second conductive patterns (22B), the first conductive patterns (22A), the second conductive patterns (22B), the first insulation (24A), and the second insulation (24B) are arranged to form the circuit.

Claim 9. The conductive sheet according to claim 7, wherein the thin metal wire has a line width of 10 (xm or less.

Claim 10. The conductive sheet according to claim 7, wherein
a projected distance (Lf) between straight lines of a side of the first large lattices (14A) and a side of the second large lattices (14B) is selected based on a size of the small lattices (18).

Claim 11. The conductive sheet according to claim 10, wherein the projected distance (Lf) is 100 to 400 μm.

Claim 12. The conductive sheet according to claim 7, wherein the first conductive part (13A) further contains first terminal wiring patterns (41a) each connected to an end of the first conductive pattern (22A) and a plurality of first terminals (116a) each connected to the corresponding first terminal wiring pattern (41a), the first terminals (116a) being formed in a longitudinal center of a side on the one main surface of the substrate (12A), and the second conductive part (13B) further contains second terminal wiring patterns (41b) each connected to an end of the second conductive pattern (22B) and a plurality of second terminals (116b) each connected to the corresponding second terminal wiring pattern (41b), the second terminals (116b) being formed in a longitudinal center of a side on the other main surface of the substrate (12A).

Claim 13. The conductive sheet according to claim 12, wherein an arrangement of a plurality of the first terminals (116a) is adjacent to an arrangement of a plurality of the second terminals (116b) as viewed from above.

Claim 14. The conductive sheet according to claim 12, wherein an end of each of the first conductive patterns (22A) is connected to the corresponding first terminal wiring pattern (41a) by a first wire connection (40a), an end of each of the second conductive patterns (22B) is connected to the corresponding second terminal wiring pattern (41b) by a second wire connection (40b), a plurality of the first wire connections (40a) are arranged in a straight line along the second direction, and a plurality of the second wire connections (40b) are arranged in a straight line along the first direction.

Claim 15. The conductive sheet according to claim 8, wherein the first insulation (24A) and the second insulation (24B) are arranged facing each other with the substrate (12A) interposed therebetween, and the overlap of the first insulation (24A) and the second insulation (24B) has a polygonal shape as viewed from above.

Claim 16. The conductive sheet according to claim 15, wherein the polygonal shape is a square shape.

Claim 17. The conductive sheet according to claim 15, wherein the polygonal shape is a wedge shape.

Claim 18. The conductive sheet according to claim 1, wherein the small lattices (18) have a polygonal shape.

Claim 19. The conductive sheet according to claim 18, wherein the small lattices (18) have a square shape.

Claim 20. A method for using a conductive sheet, comprising using a first conductive sheet (10A) and a second conductive sheet (10B), wherein the first conductive sheet (10A) contains two or more conductive first large lattices (14A) composed of a thin metal wire and a first connection (16A) composed of a thin metal wire for electrically connecting the adjacent first large lattices (14A), the first large lattices (14A) each contain a combination of two or more small lattices (18), the first connection (16A) has a width Wc1, the small lattices (18) have a pitch Ps, and the width Wcl and the pitch Ps satisfy the relation Wcl > Ps/√2, the second conductive sheet (10B) contains two or more conductive second large lattices (14B) composed of a thin metal wire and a second connection (16B) composed of a thin metal wire for electrically connecting the adjacent second large lattices (14B), the second large lattices (14B) each contain a combination of two or more small lattices (18), the second connection (16B) has a width Wc2, the small lattices (18) have a pitch Ps, and the width Wc2 and the pitch Ps satisfy the relation Wc2 > Ps/√2, two or more of the first large lattices (14A) are arranged in a first direction with the first connection (16A) disposed therebetween to form a first conductive pattern (22A) in the first conductive sheet (10A),two or more of the second large lattices (14B) are arranged in a second direction perpendicular to the first direction with the second connection (16B) disposed therebetween to form a second conductive pattern (22B) in the second conductive sheet (10B), and the first conductive sheet (10A) and the second conductive sheet (10B) are combined, so that the first connection (16A) in the first conductive sheet (10A) and the second connection (16B) in the second conductive sheet (10B) form in combination an arrangement of the small lattices (18).

Claim 21. The capacitive touch panel comprising the conductive sheet according to claim 1.