DESCRIPTION
Technical Field
The present invention relates to an optical information
medium having a micro-protrusion/depression structure.
5 Further, the present invention relates to the optical
information medium capable of utilizing adhesion to the surface
of the substrate of paper or plastic resin, or embedding inside
the paper substrate.
10 Background Art
Previously, typical methods for continuously producing a
large amount of optical information media having a microprotrusion/
depression structure have included a "pressing
method" described in Japanese Patent No. 4190473 (PTL1), a
15 "casting method" described in Japanese Utility Model
Registration Laid-Open No. 2524092 (PTL2), a "photopolymer
method" described in Japanese Patent No. 4088884 (PTL3), and
the like.
In the case where the micro-protrusion/depression
20 structure is produced by the "pressing method", the microprotrusion/
depression structure is shape transferred by
heating a resin layer which has been formed as a continuous
layer to the softening point or higher and pressing a relief
mold (a mold for reproduction of the micro25
protrusion/depression structure) against the face of the resin
layer where the micro-protrusion/depression structure will be
formed. Alternatively, the micro-protrusion/depression
structure may be shape transferred by pressing to a resin layer
a relief mold which has been heated to the softening point of
30 the resin layer or higher. In either method, a technique of
- 3 -
shape transfer is utilized, which involves pressing the relief
mold to the resin layer which has been previously formed by
whole surface coating or the like. Further, addition of
colorants such as dye or pigment allows to color the gloss
5 obtainable after providing a metal reflective layer. However,
the pressing method is predicated on the presence of the
colored resin layer throughout the whole surface of pressing
processing
In the "casting method", the shape of the micro10
protrusion/depression structure is transferred by melt
extruding a resin for forming the micro-protrusion/depression
structure which is heated to its melting point or higher onto
a relief mold (a mold for reproduction of the microprotrusion/
depression structure), or by casting a solution or
15 dispersion of the resin onto the relief mold. The microprotrusion/
depression structure is obtained by cooling the
resin to decrease its flowability to form a continuous layer,
and peel it off from the relief mold. Also in this case,
coloration is possible by adding a colorant such as dye or
20 pigment to the resin layer. However, similar to the "pressing
method", the colored resin layer exists as a continuous layer.
The "photopolymer method" (a 2P method, or a
photosensitive resin method) comprises the steps of casting a
radiation-curing resin composition between a "relief mold (a
25 mold for reproduction of the micro-protrusion/depression
structure)" and a flat substrate (such as a plastic film),
curing the resin composition by the radiation to form a
continuous layer, and peeling off the cured resin layer as
well as the substrate from the relief mold. The micro30
protrusion/depression structure of high definition can be
- 4 -
obtained by utilizing the "photopolymer method". The optical
information medium obtained by the "photopolymer method" has
a superior precision in formation of the protrusion/depression
structure, high thermal resistance, and high chemical
5 resistance, compared with those obtained by the "pressing
method" and "casting method" in which the thermoplastic resin
is used. Further, heating is unnecessary during processing,
since the radiation-curing resin composition in a liquid form
is used.
10 However, the following problem is present in any of the
molding methods of "pressing method", "casting method", and
"photopolymer method". In any of the molding methods, the
resultant resin layer is obtained as a continuous and unitary
layer. For example, it is difficult to continuously duplicate
15 a large amount of the micro-protrusion/depression structures
disposed only in desired regions of a resin layer which are
not unitary but consist of multiple parts. Also, it is
difficult to duplicate continuously a large amount of the
micro-protrusion/depression structures disposed only in
20 desired regions of a resin layer which is partially colored.
In regard to this point, it might be conceivable to form the
micro-protrusion/depression structure by disposing a colored
resin layer consisting of multiple parts onto a supporting
substrate and adjusting the position where the relief mold is
25 pressed on, in the "pressing method". However, in the case
where a resin layer consisting of multiple parts is present,
the productivity is reduced in view of register. This is
because heat-shrinkage of the supporting substrate becomes
uneven.
- 5 -
One of optical information media is an optically variable
device (OVD) as, which can be used as media for the purpose of
decoration or anti-counterfeiting. Diffraction gratings and
scattering structures are mainly used as the micro-
5 protrusion/depression structure in the OVD. Generally, any of
the "pressing method", "casting method" and "photopolymer
method" are used for forming such micro-protrusion/depression
structure. The OVD which has undergone a vapor deposition step
for disposing a reflecting layer on the micro10
protrusion/depression structure and a coating step for
disposing an adhesion layer may be in a form of a transfer
leaf, an adhesion label, a thread, or the like.
A unique metallically glossy color can be provided on
this OVD by coloring the resin layer constituting the micro15
protrusion/depression structure by colorants such as a dye or
a pigment. For example, the OVD has a silver metallic gloss
when a colorless resin layer is used and a reflective layer is
made of aluminum. On the other hand, even in the case where
the reflective layer is made of aluminum, the OVD exhibits
20 gold color when the resin layer has been colored in orange (or
yellow), or the OVD exhibits copper color when the resin layer
has been colored in reddish-brown.
In order to provide higher resistance to counterfeiting,
higher design properties and higher chemical resistance, it is
25 possible to subject the OVD to a demetallization treatment.
Demetallization treatment generally means a method comprising
the steps of: providing a mask layer having a desired pattern
onto a reflective layer made of metal, etching and partially
remove the metal with an acid or an alkali to obtain the
30 reflective layer having the desired pattern. For example,
- 6 -
demetallization-treated holograms are often provided to
securities such as bank notes.
However, the following problem exists in the case where
the OVD is produced with the demetallization treatment. If
5 the resin layer constituting the micro-protrusion/depression
structure is colored in a certain color, the part of the resin
layer where the metal is removed by the demetallization
treatment is not colorless under visual observation but
exhibits the certain color. For example, the demetallized
10 part which is desired to be colorless exhibits orange color,
when an OVD exhibiting gold metallically glossy color is
produced with the demetallization treatment. Therefore, gold
gloss of the non-demetallized part cannot be emphasized to the
general public who is a judge of genuineness, since the
15 reflective layer does not appear to be made of gold metal.
Further, it is also problematic that the same appearance can
be achieved by forming an orange coating onto the whole surface
of the counterfeited hologram.
It might be conceivable to make the reflective layer from
20 metal having non-silver gloss, against the above problem. For
example, if the micro-protrusion/depression structure is
formed with a colorless resin layer, and copper is vapor
deposited thereon instead of aluminum, and demetallization
treatment is carried out to obtain an OVD, the region where
25 the copper is removed becomes colorless, since copper itself
has copper-colored gloss.
However, this production method suffers from the
following problems. In appearance, the chemical resistance of
copper, including resistance to human sweat, is inferior to
30 that of aluminum whose oxide is white, since oxides of copper
- 7 -
are colored. Therefore, copper is not a practical material in
the actual distribution. Further, in a method for providing
the reflective layer by vapor deposition of copper, only
copper-colored reflective layer can be made, unless one or
5 more steps of vapor deposition of metal of other color, one or
more masking steps, and/or one or more etching steps are added.
For example, vapor deposition and demetallization treatment of
gold for providing gold gloss is very expensive and exhibits
low productivity compared to the case where the resin layer
10 having the micro-protrusion/depression structure is colored.
In regard to these problems, it is possible to adopt a
method of staining a part of a layer which has been formed on
the substrate before the resin layer having the microprotrusion/
depression structure. For example, a colored part
15 having a desired pattern can be provided on a surface of the
resin layer having the micro-protrusion/depression structure,
the surface being opposite to the reflective layer (that is,
between a peel layer and the resin layer having the microprotrusion/
depression structure in the hologram transfer leaf).
20 Thus, discontinuous and patterned glossy expression exhibiting
a color other than silver is achieved by the colored part and
the reflective layer. However, this method suffers from the
following problem. It is necessary to form the colored part
before formation of the resin layer having the micro25
protrusion/depression structure in this method. Therefore, in
any of the "pressing method", "casting method", and
"photopolymer method", the productivity is reduced in view of
register.
Against these problems, a self-alignment patterning is
30 proposed, which is based on difference in transmittance of
- 8 -
light of the metallic reflective layer caused by structural
difference of the resin layer having the microprotrusion/
depression structure. For example, a moth-eye
structure of sub-wavelength scale is introduced into a part of
5 the micro-protrusion/depression structure, and aluminum is
vapor deposited onto the micro-protrusion/depression structure.
Here, the layer of the vapor deposited aluminum has a
relatively small thickness on the part of the moth-eye
structure, since the part of the moth-eye structure has a large
10 surface area compared to other part. Then, a positive-working
photolithographic material is further coated onto the
reflective layer, as a mask layer, and the mask layer is
irradiated with a light for making the photolithographic
material soluble, from the side of the micro15
protrusion/depression structure-formed layer. In the part of
the moth-eye structure, the positive-working photolithographic
material becomes soluble, since the thickness of aluminum is
small to transmit the light therethrough. In the other part,
such as the part not having the moth-eye structure or a
20 diffraction grating, the positive-working photolithographic
material does not become soluble, since the light is not
transmitted. The colored part can be provided in a selfalignment
manner by washing off the solubilized
photolithographic material. However, this method suffers from
25 the following problem. In this production method, the colored
part is not provided on the front side of the general optical
information medium (that is, the side of the resin layer having
the micro-protrusion/depression layer), rather it is provided
on the back side (that is, on the side of the reflective layer
30 opposite to the resin layer). Therefore, genuineness
- 9 -
determination is possible by visual observation from the back
side. It is impossible to stain the resin layer having the
micro-protrusion/depression structure which is positioned on
the front side.
5 As described above, it is impossible to continuously
produce a large amount of demetallized optical information
media for observing a reflective layer from the side of the
micro-protrusion/depression structure-formed layer, wherein
coloration is limited only in the region where the reflective
10 layer is present, and the region where the reflective layer is
absent (that is, demetallized part) is colorless, equal to or
more than the extent of the conventional demetallized optical
information medium having uniform color (including colorless)
15 Citation List
Patent Literature
PTL1: Japanese Patent No. 4194073
PTL2: Japanese Utility Model Registration Laid-Open No.
2524092
20 PTL3: Japanese Patent No. 4088884
PTL4: International Publication No. WO 98/53013
PTL5: International Publication No. WO 96/20968
PTL6: European Patent Laid-Open No. 0688840
PTL7: International Publication No. WO 96/40813
25 PTL8: International Publication No. WO 93/17060
PTL9: International Publication No. WO 97/31073
PTL10: International Publication No. WO 2004/031256
PTL11: International Publication No. WO 2005/035613
PTL12: Japanese Patent Laid-Open No. S61-98751(1986)
30 PTL13: Japanese Patent Laid-Open No. S63-23909(1988)
- 10 -
PTL14: Japanese Patent Laid-Open No. S63-23910(1988)
PTL15: Japanese Patent Laid-Open No. 2007-118563
Non-Patent Literature
5 NPL1: E. P. Kohler et al., J. Am. Chem. Soc., Vol. 49,
pp. 3181-3188 (1927)
Summary of Invention
Technical Problem
10 One of the problems of the present invention is to provide
an optical information medium exhibiting a colored glossy
effect in which regions where a reflective layer exists are
colored in one or more colors and regions where the reflective
layer does not exist are colorless. Further, another problem
15 of the preset invention is to provide an optical information
medium exhibiting different colored glossy effect when
observed from the front and back sides, in the regions where
the reflective layer exists. Also, another problem of the
present invention is to provide an optical information medium
20 exhibiting two or more colored glossy effects and having
superior design properties and superior counterfeit resistance,
wherein the medium has a plurality of separated regions where
a reflective layer exists, each of the regions being colored
in different one or more colors, and the regions where the
25 reflective layer does not exist are colorless.
Solution to Problem
The optical information medium of the first embodiment
of the present invention comprises, in this order: a bonding
30 part (receiving layer); at least one image part; and an
- 11 -
adhesive layer (protective layer) covering the at least one
image part, wherein each of the image part comprises a microprotrusion/
depression structure including part which has a
micro-protrusion/depression structure on at least a part of a
5 surface opposite to the bonding part, a reflective layer, and
a mask layer, in the order from the bonding part (receiving
layer), the micro-protrusion/depression structure including
part is colorless or colored in one or more translucent or
opaque color, and at least one of the micro10
protrusion/depression structure including part of the image
part is colored in one or more translucent or opaque color.
Here, the at least one image part may be a non-separated
unitary image part or two or more image parts separated from
each other. Further, in each of the image part, the micro15
protrusion/depression structure including part may be
colorless or colored in one color. Alternatively, the microprotrusion/
depression structure including part may be colored
in two or more color, in at least one of the image parts.
Alternatively, the micro-protrusion/depression structure
20 including part may have a peripheral area colored in one color,
and an internal area surrounded by the peripheral area and
colored in one or more color different from the color of the
peripheral area, in at least one of the image parts. Further,
the micro-protrusion/depression structure including part in
25 one of the image parts may be colored in color different from
the colors of the micro-protrusion/depression structure
including part in the other image part.
In the optical information medium of a variation of the
first embodiment of the present invention, the mask layer may
30 be colorless or colored in one or more colors, in each of the
- 12 -
image parts. Here, the mask layer in one of the image parts
may be colored in color different from the colors of the mask
layer in the other image parts. Also, the mask layer may be
colored in two or more color, in at least one of the image
5 parts. Further, the mask layer may have a peripheral area
colored in one color, and an internal area surrounded by the
peripheral area and colored in one or more color different
from the color of the peripheral area, in at least one of the
image parts.
10 In the above-described optical information medium, the
bonding part and the adhesive layer may be colorless.
Alternatively, the adhesive layer may be colored in one or
more translucent or opaque colors.
Further, in the above-described optical information
15 medium, at least two of the image parts may have different
area(size). Alternatively, the micro-protrusion/depression
structure including part in one of the image parts may have
the micro-protrusion/depression structure different from that
of the micro-protrusion/depression structure including part in
20 the other image parts.
A transfer leaf of the second embodiment of the present
invention comprises: the optical information medium according
to the first embodiment or variation thereof; and a carrier
substrate which is in contact with the bonding part (receiving
25 layer), wherein it is able to be peeled at an interface between
the bonding part (receiving layer) and the carrier substrate.
A label of the third embodiment of the present invention
comprises: the optical information medium according to the
first embodiment or variation thereof; and a removable
30 substrate (peel sheet) being in contact with the adhesive layer
- 13 -
(protective layer), wherein the adhesive layer (protective
layer) has tackiness, and it is able to be peeled at an
interface between the adhesive layer (protective layer) and
the removable substrate (peel sheet).
5 A papermaking thread of the fourth embodiment of the
present invention comprises: the optical information medium
according to the first embodiment or variation thereof; and a
carrier substrate which is in contact with the bonding part
(receiving layer); and a carrier-substrate-side adhesive layer
10 (second adhesive layer) which is in contact with the carrier
substrate.
A laminated body of the fifth embodiment of the present
invention comprises a substrate and the optical information
medium according to the first embodiment or variation thereof
15 which is attached to the substrate.
A printed article of the sixth embodiment of the present
invention comprises a substrate containing a printed part in
which a printing ink is adhered, and the optical information
medium according to the first embodiment or variation thereof
20 which is attached to the substrate.
Advantageous Effects of Invention
By adopting the above-described construction, it becomes
possible to provide an optical information medium having more
25 superior design properties and higher counterfeit resistance,
which has colorless regions and one or more image parts having
non-silver glossy expression such as gold or copper color.
This optical information medium is difficult to be formed by
the conventional "pressing method", "casting method" or
30 "photopolymer method". Further, there is no limitation for
- 14 -
selection of the material of the reflective layer, and thereby
it is possible to form the reflective layer from the material
having physical strength and chemical resistance equal to or
higher than those of aluminum. This is because the glossy
5 expression is provided by coloration of the constituent layers
other than the reflective layer. Further, the design properties
and counterfeit resistance can be improved by disposing a
plurality of colored parts in each of one or more image parts.
In addition, different glossy expression under observation
10 from the front and back sides can be obtained by coloring the
micro-protrusion/depression structure including part and the
mask layer in different color in each of one or more image
parts, and thereby the design properties and counterfeit
resistance can be further improved.
15 The optical information medium having the above-described
construction can be used as a transfer leaf, a label, a
papermaking thread, and the like. Further, it is possible to
provide a laminated body and a printed article having superior
design properties and high counterfeit resistance by
20 introducing the optical information medium having the abovedescribed
construction into a substrate which may have a
printed part. Therefore, the above-described optical
information medium is useful in various industries.
25 Brief Description of Drawings
Fig. 1 is a schematic cross-sectional view showing an
optical information medium according to the first embodiment
of the present invention;
- 15 -
Fig. 2 is a schematic cross-sectional view showing a
transfer leaf according to the second embodiment of the present
invention;
Fig. 3 is a schematic cross-sectional view showing a
5 label according to the third embodiment of the present
invention;
Fig. 4 is a schematic cross-sectional view showing a
papermaking thread according to the fourth embodiment of the
present invention;
10 Fig. 5A is a schematic plan view showing the front side
of one constitutional example of a printed article according
to the sixth embodiment of the present invention which
comprises an optical information medium transferred on a
substrate;
15 Fig. 5B is a schematic plan view showing the back side
of one constitutional example of a printed article according
to the sixth embodiment of the present invention which
comprises an optical information medium transferred on a
substrate;
20 Fig. 6A is a schematic plan view showing the front side
of the other constitutional example of a printed article
according to the sixth embodiment of the present invention
which comprises a label adhered on a substrate;
Fig. 6B is a schematic plan view showing the back side
25 of the other constitutional example of a printed article
according to the sixth embodiment of the present invention
which comprises a label adhered on a substrate;
Fig. 7A is a schematic plan view showing the front side
of the other constitutional example of a printed article
30 according to the sixth embodiment of the present invention
- 16 -
which comprises a papermaking thread embedded inside a
substrate;
Fig. 7B is a schematic plan view showing the back side
of the other constitutional example of a printed article
5 according to the sixth embodiment of the present invention
which comprises a papermaking thread embedded inside a
substrate;
Fig. 8 is a schematic diagram of one example of the device
for using production of an optical information medium according
10 to the first embodiment of the present invention;
Fig. 9A is a schematic plan view showing the front side
of the printed article of Example 1 which comprises an optical
information medium transferred on a transparent substrate;
Fig. 9B is a schematic plan view showing the back side
15 of the printed article of Example 1 which comprises an optical
information medium transferred on a transparent substrate;
Fig. 10A is a schematic plan view showing the front side
of the printed article of Example 2 which comprises a label
adhered on a transparent substrate;
20 Fig. 10B is a schematic plan view showing the back side
of the printed article of Example 2 which comprises a label
adhered on a transparent substrate;
Fig. 11A is a schematic plan view showing the front side
of the printed article of Example 3 which comprises an optical
25 information medium transferred on a transparent substrate;
Fig. 11B is a schematic plan view showing the back side
of the printed article of Example 3 which comprises an optical
information medium transferred on a transparent substrate;
- 17 -
Fig. 12A is a schematic plan view showing the front side
of the printed article of Example 4 which comprises a label
adhered on a transparent substrate;
Fig. 12B is a schematic plan view showing the back side
5 of the printed article of Example 4 which comprises a label
adhered on a transparent substrate;
Fig. 13A is a schematic plan view showing the front side
of the printed article of Example 5 which comprises a
papermaking thread embedded inside an opaque substrate;
10 Fig. 13B is a schematic plan view showing the back side
of the printed article of Example 5 which comprises a
papermaking thread embedded inside an opaque substrate;
Fig. 14 is a schematic cross-sectional view showing the
transfer leaf of Example 6;
15 Fig. 15A is a schematic plan view showing the front side
of the printed article of Example 6 which comprises an optical
information medium transferred on an opaque substrate;
Fig. 15B is a schematic plan view showing the back side
of the printed article of Example 6 which comprises an optical
20 information medium transferred on an opaque substrate;
Fig. 16 is a schematic cross-sectional view showing the
transfer leaf used in Comparative Example;
Fig. 17A is a schematic plan view showing the front side
of the printed article obtained in Comparative Example;
25 Fig. 17B is a schematic plan view showing the back side
of the printed article obtained in Comparative Example;
Fig. 18A is a schematic plan view showing the front side
of the printed article of Example 7 which comprises an optical
information medium comprising a non-separated one image part
30 and transferred on a transparent substrate;
- 18 -
Fig. 18B is a schematic plan view showing the back side
of the printed article of Example 7 which comprises an optical
information medium comprising a non-separated one image part
and transferred on a transparent substrate;
5 Fig. 19A is a schematic plan view showing the front side
of the printed article of Example 8 which comprises an optical
information medium comprising a non-separated one image part
and transferred on a transparent substrate;
Fig. 19B is a schematic plan view showing the back side
10 of the printed article of Example 8 which comprises an optical
information medium comprising a non-separated one image part
and transferred on a transparent substrate;
Fig. 20A is a schematic plan view showing the front side
of the printed article of Example 9 which comprises a label
15 comprising a non-separated one image part and transferred on
a transparent substrate;
Fig. 20B is a schematic plan view showing the back side
of the printed article of Example 9 which comprises a label
comprising a non-separated one image part and transferred on
20 a transparent substrate;
Fig. 21A is a schematic plan view showing the front side
of the printed article of Example 10 which comprises a
papermaking thread comprising a non-separated one image part
and embedded inside an opaque substrate;
25 Fig. 21B is a schematic plan view showing the back side
of the printed article of Example 10 which comprises a
papermaking thread comprising a non-separated one image part
and embedded inside an opaque substrate;
Fig. 22A is a schematic plan view showing the front side
30 of the printed article of Example 11 which comprises an optical
- 19 -
information medium comprising a non-separated one image part
and transferred on an opaque substrate; and
Fig. 22B is a schematic plan view showing the back side
of the printed article of Example 11 which comprises an optical
5 information medium comprising a non-separated one image part
and transferred on an opaque substrate.
Description of Embodiments
The optical information medium of the first embodiment
10 of the present invention comprises, in this order: a bonding
part (receiving layer); at least one image part; and an
adhesive layer (protective layer) covering the at least one
image part, wherein each of the image parts comprises a microprotrusion/
depression structure including part which has a
15 micro-protrusion/depression structure on at least a part of a
surface opposite to the bonding part, a reflective layer, and
a mask layer, in the order from the bonding part (receiving
layer), the micro-protrusion/depression structure including
part is colorless or colored in one or more translucent or
20 opaque color, and the micro-protrusion/depression structure
including part of one of the image part is colored in different
color from the color of the micro-protrusion/depression
structure including part in the other image parts. In this
embodiment, the at least one image part may be non-separated
25 one image part, or two or more image parts separated from each
other. Fig. 1 shows a schematic cross-sectional view of an
optical information medium (1) comprising four image parts
(40a-d) separated from each other. The optical information
medium (1) comprises a bonding part (30), four image parts
30 (40a-d) formed on the bonding part (30), and an adhesive layer
- 20 -
(50) covering the four image parts (40), wherein each of the
image parts (40a-d) comprises a micro-protrusion/depression
structure including part (42a-d), a reflective layer (44a-d),
and a mask layer (46a-d), in this order from the side of the
5 bonding part (30). Besides, the number of the image parts is
not limited to 4, but may be 1, 2, 3, or 5 or more.
Hereinafter, this embodiment will be explained with reference
to the exemplary case where four image parts (40a-d) exist as
shown in Fig. 1.
10
The bonding part (30) has a function to keep the four
image part (40a-d) at the predetermined positons. The bonding
part (30) desirably has a thickness in a range from 1 m to 20
m. The bonding part (30) is preferably colorless. The
15 bonding part (30) has a transmittance of preferably from 10%
to 90%, and more preferably from 50% to 95%, within a
wavelength range from 400 nm to 700 nm.
The micro-protrusion/depression structure including part
(42a-d) in this embodiment is not a layer formed continuously
20 on the surface of the bonding part (30). Each of the microprotrusion/
depression structure including part (42a-d) in this
embodiment are independent from each other in each of the image
parts (40a-d), and disposed at a desired interval. Further,
the micro-protrusion/depression structure including part (42a25
d) is colorless, or colored in one or more translucent or
opaque color. Variously designed expression can be afforded as
compared to the case where the micro-protrusion/depression
structure is formed on a unitary layer which has been formed
uniformly throughout the whole medium. This is because each
- 21 -
of the micro-protrusion/depression structure including part
(42a-d) can be separately colored in different color.
The micro-protrusion/depression structure including part
(42a-d) comprises a micro-protrusion/depression structure
5 selected from the group consisting of a relief hologram, a
diffraction grating, a scattering structure, a directional
structure, an interference structure, a blazed grating, a subwavelength
grating, a micro lens, a polarization element, a
Fresnel lens, a lenticular lens, a diffusion structure, and an
10 anti-reflective structure, on the surface on the side of the
reflective layer (44a-d). Fig. 1 exemplarily shows the case
where the micro-protrusion/depression structure is formed on
the whole surface of the micro-protrusion/depression structure
including part (42a-d) on the side of the reflective layer
15 (44a-d). However, the micro-protrusion/depression structure
may be formed only on part of the surface of the microprotrusion/
depression structure including part (42a-d) on the
side of the reflective layer (44a-d). Alternatively, plural
types of the micro-protrusion/depression structure may be
20 formed on the surface of one of the micro-protrusion/depression
structure including part (42a-d), the surface being on the
side of the reflective layer (44a-d). Further, the microprotrusion/
depression structure including part (42a) of one of
the image parts (for example, 40a) may be different from the
25 micro-protrusion/depression structure including parts (42b-d)
of the other image parts (for example, 42b-d).
In this embodiment, the term "translucent" means a
colored state where the incident light into and the reflected
light from the reflective layer (44a-d) pass through to the
30 extent that the optical effect caused by the micro-
22 -
protrusion/depression structure is visible. Further, in this
embodiment, the term "opaque" means a colored state where the
incident light into and the reflected light from the reflective
layer (44a-d) is blocked out to the extent that the optical
5 effect caused by the micro-protrusion/depression structure is
not visible. In this embodiment, in each of the four image
parts (40a-d), the micro-protrusion/depression structure
including part (42a-d) may be colorless, or may be colored in
one color. Further, in at least one of the image parts (40a10
d), the micro-protrusion/depression structure including part
(42a-d) may be colored in two or more color. For example, in
at least one of the image parts (40a-d), the microprotrusion/
depression structure including part (42a-d) may
have a peripheral area colored in one color, and an internal
15 area surrounded by the peripheral area and colored in one or
more color different from the color of the peripheral area.
In a preferable constitutional example, the microprotrusion/
depression structure including part (42a) of one of
the image parts (for example, 40a) may be differently colored
20 from the micro-protrusion/depression structure including parts
(42b-d) of the other image parts (for example, 40b-d). In a
more preferable constitutional example, the microprotrusion/
depression structure including part (42a-d) of each
of the image parts (40a-d) may be differently colored from the
25 micro-protrusion/depression structure including part (42a-d)
of the other image parts (40a-d).
In this embodiment, two micro-protrusion/depression
structure including parts (42) being "differently colored
means one of the following conditions: (i) one of the micro30
protrusion/depression structure including part being colorless,
- 23 -
and the other micro-protrusion/depression structure is colored
in one or more color; (ii) if the two microprotrusion/
depression structures are colored in one color, the
color of one of the micro-protrusion/depression structure is
5 different from the color of the other microprotrusion/
depression structure; or (iii) if the two microprotrusion/
depression structures are colored in plural color,
at least one color existing in one of the microprotrusion/
depression structures is not present in the other
10 micro-protrusion/depression structure.
The micro-protrusion/depression structure including part
(42a-d) may have a thickness in a range from 0.5 m to 30 m,
preferably from 0.1 m to 10 m. Besides, in a view point of
facilitating the formation of the micro-protrusion/depression
15 structure including part (42a-d), the microprotrusion/
depression structure including part (42a-d)
desirably has a thickness three to ten times as large as the
maximum height of the micro-protrusion/depression structure
existing its surface. Depending on the viscosity (flowability)
20 of the resin in an uncured state which is used in the microprotrusion/
depression structure including part (42a-d),
adoption of the thickness within the above-described range
allows to prevent flash of the uncured resin and generation of
wrinkles during formation, thereby obtaining the micro25
protrusion/depression structure including part (42a-d) having
a good shape.
The reflective layer (44a-d) is disposed on the microprotrusion/
depression structure including part (42a-d). The
reflective layer does not exist in regions where the micro30
protrusion/depression structure including part (42a-d) is not
- 24 -
present. The surface of the reflective layer (44a-d) on the
side of the micro-protrusion/depression structure including
part (42a-d) has a protrusion/depression face caused by the
micro-protrusion/depression structure of the micro-
5 protrusion/depression structure including part (42a-d). The
surface of the reflective layer (44a-d) on the side of the
mask layer (46a-d) has a protrusion/depression face which the
micro-protrusion/depression structure of the microprotrusion/
depression structure including part (42a-d) is
10 inverted. In other words, the reflective layer (44a-d) provides
an optical effect due to the micro-protrusion/depression
structure of the micro-protrusion/depression structure
including part (42a-d), on both sides. As a result, it becomes
possible not only to provide glossy expression caused by
15 combination of the reflective layer (44a-d) and the colors of
the micro-protrusion/depression structure including part (42ad)
under observation from the front side, but also to provide
colored glossy expression caused by combination of the
reflective layer (44a-d) and the colors of the mask layer (46a20
d) under observation from the back side. Besides, in regions
of the micro-protrusion/depression structure including part
(42a-d) where the micro-protrusion/depression structure is not
formed, the reflective layer (44a-d) provides regularly
reflected light on both front and back sides.
25 As described below, the reflective layer (44a-d) can be
produced by forming a reflective material layer on the whole
surface of the optical information medium as a continuous layer,
forming a patterned mask layer (46a-d) at the positions
corresponding to the micro-protrusion/depression structure
30 including part (42a-d), selectively removing the exposed part
- 25 -
of the reflective material layer by etching in which the mask
layer (46a-d) is used as an etching mask. The reflective layer
(44a-d) preferably has a thickness within a range from 10 nm
to 300 nm. As described below, in the case where the reflective
5 layer (44a-d) is formed by a printing method, it is preferable
to adjust the thickness after drying within a range from 1 nm
to 10 m.
The reflective layer (44a-d) typically has the same top
view shape as that of the micro-protrusion/depression
10 structure including part (42a-d). The term "top view shape"
means a shape under observation from the perpendicular
direction to the surface of the bonding part (30). However,
the reflective layer (44a-d) may be formed only on partial
regions of the micro-protrusion/depression structure including
15 part (42a-d). The reflective layer (44a-d) of this type can be
formed by paster processing, water-washing sealite processing,
laser processing, or the like. Alternatively, a sea-island
reflective layer (44a-d) can be obtained by vapor depositing
tin or the like to form a reflective material layer having a
20 micro see-island structure, and etching in which the abovedescribed
mask layer (46a-d) is used as an etching mask. The
term "see-island reflective layer" means a discontinuous layer
consisting of plural parts of the reflective material which
are separate from each other, or a layer of the reflective
25 material having a plurality of through-holes. Providing the
reflective layer (44a-d) only on partial regions of the microprotrusion/
depression structure including part (42a-d) allows
to achieve more superior design properties, since it becomes
possible to visually observe both of the glossy expression
30 caused by the combination of the reflective layer (44a-d) and
- 26 -
the micro-protrusion/depression structure including part (42ad),
and the chromatic expression only due to the color of the
micro-protrusion/depression structure including part (42a-d)
simultaneously, under observation from the front side.
5 The reflective layer (44a-d) may have a transmittance of
not less than 20% in a range of wavelength of 400 nm to 700
nm. In this case, the effect of the optical element under
transmission mode is available. Further, information disposed
under the reflective layer becomes visible, for example,
10 information of the printed part (130) on the receiving
substrate (110) such as a portrait, characters, patterns, and
the like as described below.
The mask layer (46a-d) is formed on the reflective layer
(44a-d). The mask layer (46a-d) has the same top view shape as
15 that of the micro-protrusion/depression structure including
part (42a-d), including the case where the reflective layer
(44a-d) is formed only on partial regions of the microprotrusion/
depression structure including part (42a-d). This
is because the mask layer (46a-d) has a function as the etching
20 mask during formation of the reflective layer (44a-d), as
described above. The surface of the mask layer (46a-d) opposite
to the reflective layer (44a-d) may be flat, or have
protrusion/depression to which the micro-protrusion/depression
structure of the reflective layer (44a-d) is reflected.
25 In the variation of this embodiment, the mask layer (46ad)
may be colorless, or colored in one color, in each of the
four image parts (40a-d). Further, the mask layer (46a-d) may
be colored in two or more color in at least one of the image
parts (40a-d). For example, the mask layer (46a-d) may have
30 a peripheral area colored in one color, and an internal area
- 27 -
surrounded by the peripheral area and colored in one or more
color different from the color of the peripheral area, in at
least one of the image parts (40a-d). In a preferred
constitutional example, the mask layer (46a) in one of the
5 image parts (for example, 40a) may be differently colored from
the mask layers (46b-d) in the other image parts (for example,
40b-d). In a more preferred constitutional example, the mask
layer (46a-d) of each of the image parts (40a-d) is differently
colored from the mask layers (46a-d) of the other image parts
10 (40a-d). The definition of "differently colored" for the mask
layer (46a-d) is similar to that for the microprotrusion/
depression structure including part (42a-d).
The adhesive layer (50) is formed so as to cover the four
image parts (40a-d) consisting of the micro15
protrusion/depression structure including part (42a-d), the
reflective layer (44a-d) and the mask layer (46a-d). That is,
the interstices of the four image parts (40a-d) are filled
with the adhesive layer (50). The adhesive layer 50 desirably
has a thickness of 1 m to 20 m over the top surface of the
20 image parts (40a-d) (the surface of the mask layer (46a-d)
opposite to the reflective layer (44a-d)). The adhesive layer
(50) is useful for keeping the four image parts (40a-d) at the
predetermined positions, and for isolating the constituting
layers of the image parts (40a-d) from the external environment.
25 In this embodiment (including variation thereof), the
adhesive layer (50) may be typically colorless. It is possible
to make the regions other than the image parts (40a-d) (that
is, background) colorless, by making the bonding part (30) and
the adhesive layer (50) colorless. In this case, information
30 disposed under the optical information medium (1) is visible
- 28 -
in the regions other than the image parts (40a-d) of the
optical information medium (1) of this embodiment, for example,
information of the printed part (130) on the receiving
substrate (110) such as a portrait, characters, patterns, and
5 the like, as described below. Alternatively, the adhesive layer
(50) may be colored, in a desired design. In this case,
arbitrary chromatic expression can be provided in the regions
other than the image parts (40a-d) (that is, background), under
observation from the front side. The background color in this
10 case can be selected independently from the color of the microprotrusion/
depression structure including part (42a-d), and
therefore allows to provide more superior design properties to
the optical information medium (1).
Fig. 1 shows the case where the four image parts (40a-d)
15 have the same area in top view and the same microprotrusion/
depression structure. However, at least two of the
four image parts (40a-d) may have different area in top view
from each other. Alternatively, each of the four image parts
(40a-d) may have different area in top view from each other.
20 Further the micro-protrusion/depression structure of the
micro-protrusion/depression structure including part (42a) of
one of the image parts (for example, 40a) may have different
shape from the micro-protrusion/depression structure of the
micro-protrusion/depression structure including part (42b-d)
25 of the other image parts (for example, 40b-d). Alternatively,
each of the micro-protrusion/depression structure including
part (42a) of the image parts (for example, 40a) may have
differently shaped micro-protrusion/depression structure from
each other. These modifications allow to improve flexibility
- 29 -
and design properties of the information displayed by the
optical information medium (1) of this embodiment.
The transfer leaf of the second embodiment of the present
invention comprises: the optical information medium according
5 to the first embodiment or variation thereof; and a carrier
substrate which is in contact with the bonding part (receiving
layer), wherein it is able to be peeled at an interface between
the bonding part (receiving layer) and the carrier substrate.
The bonding part (30), adhesive layer (50) and the micro10
protrusion/depression structure including part (42a-d), the
reflective layer (44a-d), and the mask layer (46a-d) which
constitute the micro-protrusion/depression structure including
part (42a-d) are similar to those in the first embodiment.
Fig. 2 shows a schematic cross-sectional view of the transfer
15 leaf (2) having four image parts (40a-d) separated from each
other. The transfer leaf (2) comprises a carrier substrate
(20), the bonding part (30), the four image parts (40a-d)
formed on the bonding part (30), and the adhesive layer (50)
covering the four image parts (40), wherein each of the four
20 image parts (40a-d) comprises the micro-protrusion/depression
structure including part (42a-d), the reflective layer (44ad),
and the mask layer (46a-d) in this order from the side of
the bonding part (30).
The carrier substrate (20) acts as a support of the
25 optical information medium (1) before transferring. Also, the
carrier substrate (20) can act as a support during formation
of the optical information medium (1). In this embodiment, the
surface of the carrier substrate (20) on the side of the
bonding part (30) may be treated for enhancing releasability
30 on transferring. In the transfer leaf (2) of this embodiment,
- 30 -
adhesion between the carrier substrate (20) and the bonding
part (30) is set lower than both of adhesion between the
bonding part (30) and the adhesive layer (50) and force
required in cohesive failure of the bonding part (30) and the
5 adhesive layer (50).
The label of the third embodiment of the present
invention comprises: the optical information medium according
to the first embodiment or variation thereof; and a removable
substrate (peel sheet) being in contact with the adhesive layer
10 (protective layer), wherein the adhesive layer (protective
layer) has tackiness, and it is able to be peeled at an
interface between the adhesive layer (protective layer) and
the removable substrate (peel sheet). The bonding part (30),
adhesive layer (50) and the micro-protrusion/depression
15 structure including part (42a-d), the reflective layer (44ad),
and the mask layer (46a-d) which constitute the microprotrusion/
depression structure including part (42a-d) are
similar to those in the first embodiment. Fig. 3 shows a
schematic cross-sectional view of the label (3) having four
20 image parts (40a-d) separated from each other. The label (3)
comprises a carrier substrate (20), the bonding part (30), the
four image parts (40a-d) formed on the bonding part (30), the
adhesive layer (50) covering the four image parts (40), and
the removable substrate (60) being in contact with the adhesive
25 layer (50), wherein each of the four image parts (40a-d)
comprises the micro-protrusion/depression structure including
part (42a-d), the reflective layer (44a-d), and the mask layer
(46a-d) in this order from the side of the bonding part (30).
The label (3) can be used to adhere a label body (3') consisting
30 of the optical information medium (1) and the carrier substrate
- 31 -
(20) to a desired substrate by first peeling the removable
substrate (60), and then bringing the adhesive layer (50) into
contact with the desired substrate.
The carrier substrate (20) in this embodiment has similar
5 function to that in the second embodiment. However, the
treatment to enhance releasability is not applied to the
surface of the carrier substrate (20) on the side of the
bonding part (30). This is because the carrier substrate (20)
is used as a protective layer for the underlying optical
10 information medium (1). Further, in this embodiment, the
carrier substrate (20) is desirably colorless and transparent,
for allowing visual observation of the optical information
medium (1) from the side of the carrier substrate (20).
The removable substrate (60) in this embodiment has a
15 function to prevent adhesion of the label body (3') due to
inadvertent contact before intended adhesion. The surface of
the removable substrate (60) on the side of the adhesive layer
(50) may be treated to enhance releasability from the adhesive
layer (50). In this embodiment, adhesion between the removable
20 substrate (60) and the adhesive layer (50) is set lower than
any of: adhesion between the carrier substrate (20) and the
bonding part (30); adhesion between the bonding part (30) and
the adhesive layer (50); and force required in cohesive failure
of the bonding part (30) and the adhesive layer (50).
25 A papermaking thread of the fourth embodiment of the
present invention comprises: the optical information medium
according to the first embodiment or variation thereof; and a
carrier substrate which is in contact with the bonding part
(receiving layer); and a carrier-substrate-side adhesive layer
30 (second adhesive layer) which is in contact with the carrier
- 32 -
substrate. The bonding part (30), adhesive layer (50) and the
micro-protrusion/depression structure including part (42a-d),
the reflective layer (44a-d), and the mask layer (46a-d) which
constitute the micro-protrusion/depression structure including
5 part (42a-d) are similar to those in the first embodiment.
The carrier substrate (20) is similar to that in the third
embodiment. Fig. 4 shows a schematic cross-sectional view of
the papermaking thread (4) having four image parts (40a-d)
separated from each other. The papermaking thread (4) comprises
10 a carrier-substrate-side adhesive layer (70), a carrier
substrate (20), the bonding part (30), the four image parts
(40a-d) formed on the bonding part (30), the adhesive layer
(50) covering the four image parts (40), and the removable
substrate (60) being in contact with the adhesive layer (50),
15 wherein each of the four image parts (40a-d) comprises the
micro-protrusion/depression structure including part (42a-d),
the reflective layer (44a-d), and the mask layer (46a-d) in
this order from the side of the bonding part (30). When making
a substrate, such as paper, from a fibrous material, the
20 papermaking thread (4) can be embedded inside the substrate.
Typically, the carrier-substrate-side adhesive layer (70) may
be colorless.
The laminated body of the fifth embodiment of the present
invention comprises a substrate and the optical information
25 medium according to the first embodiment or variation thereof
which is attached to the substrate. The printed article of the
sixth embodiment of the present invention comprises a substrate
containing a printed part in which a printing ink is adhered,
and the optical information medium according to the first
30 embodiment or variation thereof which is attached to the
- 33 -
substrate. Figs. 5A and 5B show one constitutional example of
the printed article of the sixth embodiment. Fig. 5A is a
schematic plan view showing the front side of the printed
article, and Fig. 5B is a schematic plan view showing the back
5 side of the printed article. The example shown in Figs. 5A and
5B is a printed article comprising a receiving substrate (110)
including a printed part (130) and an optical information
medium (1) having a stripe shape and transferred onto the
receiving substrate (110). Here, a constitution that the
10 printed part (130) is omitted from the constitutional example
shown in Fig. 5A and 5B corresponds to the laminated body of
the fifth embodiment. Further, the constitutional example
shown in Figs. 5A and 5B can be obtained by transferring the
optical information medium (1) onto the receiving substrate
15 (110) using the transfer leaf (2) of the second embodiment.
The "front" face (Front Side) and the "back" face
(Reverse Side) in the optical information medium (1), the
transfer leaf (2), the label (3), the papermaking thread (4),
the laminated body and the printed article (100) are defined
20 with positional relationship to the bonding part (30) and the
adhesive layer (50). More specifically, the face near to the
bonding part (30) side is "front" and the face near to the
adhesive layer (50) side is "back".
Figs. 5A and 5B show a constitutional example in which
25 the receiving substrate (110) is transparent. Therefore, an
image involving glossy expression caused by the reflective
layer (44a-d) and the micro-protrusion/depression structure
including part (42a-d) is visible in the four image parts (40ad)
of the optical information medium (1), under observation
30 from the front side shown in Fig. 5A. On the other hand, an
- 34 -
image involving glossy expression caused by the reflective
layer (44a-d) and the mask layer (46a-d) is visible in the
four image parts (40a-d) of the optical information medium (1),
under observation from the back side shown in Fig. 5B.
5 Figs. 6A and 6B show another constitutional example of
the printed article of the sixth embodiment. Fig. 6A is a
schematic plan view showing the front side of the printed
article, and Fig. 6B is a schematic plan view showing the back
side of the printed article. The constitutional example shown
10 in Figs. 6A and 6B is the printed article (110) comprising a
receiving substrate (110) including a printed part (130) and
a label body (3') having a patch (island) shape and adhered
onto the receiving substrate (110). The constitutional example
shown in Figs. 6A and 6B can be formed by peeling off the
15 removable substrate (60) from the label (3) of the third
embodiment, and adhering the label body (3') onto the receiving
substrate (110).
Figs. 6A and 6B show a constitutional example in which
the receiving substrate (110) is transparent. Therefore, an
20 image involving glossy expression caused by the reflective
layer (44a-d) and the micro-protrusion/depression structure
including part (42a-d) is visible in the four image parts (40ad)
of the label body (3'), under observation from the front
side shown in Fig. 6A. On the other hand, an image involving
25 glossy expression caused by the reflective layer (44a-d) and
the mask layer (46a-d) is visible in the four image parts (40ad)
of the label body (3'), under observation from the back
side shown in Fig. 5B.
Figs. 7A and 7B show another constitutional example of
30 the printed article of the sixth embodiment. Fig. 7A is a
- 35 -
schematic plan view showing the front side of the printed
article, and Fig. 7B is a schematic plan view showing the back
side of the printed article. The constitutional example shown
in Figs. 7A and 7B is the printed article (110) comprising a
5 receiving substrate (110) including a printed part (130) and
a papermaking thread (4) embedded inside the receiving
substrate (110). Further, the papermaking thread (4) having
four image parts (40a-d) is illustrated. The constitutional
example shown in Figs. 7A and 7B can be formed by forming the
10 receiving substrate along with embedding the papermaking
thread (4) inside, and applying printing ink onto the surface
of the receiving substrate (110) to form the printed part (130).
Figs. 7A and 7B show a constitutional example in which
the receiving substrate (110) is opaque, and the papermaking
15 thread (4) is exposed in four receiving substrate windows (120)
provided on the front side face of the receiving substrate
(110). Therefore, an image involving glossy expression caused
by the reflective layer (44a-d) and the microprotrusion/
depression structure including part (42a-d) is
20 visible in the four image parts (40a-d) of the papermaking
thread (4), under observation from the front side shown in Fig.
7A. On the other hand, the papermaking thread (4) is not
visible under observation from the back side shown in Fig. 7B,
due to opacity of the receiving substrate (110).
25 In the fifth and sixth embodiments, the receiving
substrate (110) may be transparent or opaque. In the case where
the transparent receiving substrate (110) is used as shown in
Figs. 5A-6B, the image part (40a-d) is visible under
observation from both front and back sides of the printed
30 article (100). On the other hand, in the case where the opaque
- 36 -
receiving substrate (110) is used, the image part (40a-d) is
visible only under observation from front side of the printed
article (100). Besides, in the case where the papermaking
thread (4) of the fourth embodiment is used, the receiving
5 substrate (110) is typically opaque. Therefore, the image parts
(40a-d) are made visible by providing the receiving substrate
window (120) at desired positions. Here, Figs. 7A and 7B show
a constitution that the receiving substrate window (120) is
provided only on the front side of the receiving substrate
10 (110) to make the image parts (40a-d) visible only from the
front side. However, the image parts (40a-d) may be made
visible from the back side, by further providing the receiving
substrate window (120) on the back side of the receiving
substrate (110). In this case, an image involving glossy
15 expression caused by the reflective layer (44a-d) and the mask
layer (46a-d) is visible from the back side. The shape and
number of the receiving substrate window (120) can be changed
as desired.
In addition, Figs. 5A to 7B show examples in which the
20 printed part (130) is provided at the position separate from
the image parts (40a-d). However, the printed part (130) may
be disposed at a position so that the printed part (130) is
superposed on the image part (40a-d) or at a position so that
the printed part (130) surrounds the image part (40a-d).
25 Further, Figs. 5A to 7B show examples in which the image
parts (40a-d) are registered and fixed to the receiving
substrate (110). However, a design (image) having a repeated
pattern such as a wall paper may be formed by providing a
larger number of image parts.
- 37 -
Hereinafter, each of the constituent layers used in the
above-described embodiments will be explained.
(Carrier substrate (20))
The carrier substrate (20) is preferably a film made from
5 thermoplastic resin. The thermoplastic resin desirably has
heat resistance to the extent that no deformation and/or
degradation occurs due to heat applied during formation of the
optical information medium (1) and the like (especially, heat
applied during curing and/or transferring of the respective
10 constituent layers). Non-limiting examples of the useful
thermoplastic resin include polyethylene terephthalate (PET)
polyethylene naphthalate (PEN), polypropylene (PP), and the
like.
The treatment to enhance releasability in the case of the
15 transfer leaf (2) of the second embodiment comprises
application of silicone resin or fluorine resin, for example.
(Bonding part (30))
The bonding part (30) desirably has a function to receive
the micro-protrusion/depression structure including part (42a20
d) which is thermally transferred by the method described below.
Further, the bonding part (30) has a function to keep the
micro-protrusion/depression structure including parts (42a-d),
which is not a continuous layer but is disposed separately, at
the predetermined positions. In view of these points, the
25 bonding part (30) is preferably formed from adhesive resin.
Non-limiting examples of the adhesive resin include
thermoplastic resin such as polyester resin, acrylic resin,
vinyl chloride resin, vinyl resin, polyamide resin, vinyl
acetate resin, rubber-type resin, ethylene-vinyl acetate
- 38 -
copolymer resin, and vinyl chloride-vinyl acetate copolymer
resin, for example.
In the transfer leaf (2) of the second embodiment, the
interface between the bonding part (30) and the carrier
5 substrate (20) is separated when the optical information medium
(1) consisting of the bonding part (30), the image part (40)
and the adhesive layer (50) is transferred onto the receiving
substrate (110). In order to facilitate the separation at this
interface, a treatment for enhancing releasability to the
10 carrier substrate (20) may be conducted. In addition, the
bonding part (30) may be formed from material to function as
a releasing layer upon the above-described transferring. For
example, after transfer of the micro-protrusion/depression
structure including part (42a-d), it may be carried out to
15 further cure the bonding part (30).
(Micro-protrusion/depression structure including part
(42a-d))
The micro-protrusion/depression structure including part
(42a-d) can be formed from thermosetting resin, oxidative20
polymerizable resin, reaction curing resin, ultraviolet curing
resin, electron beam curing resin, thermoplastic resin, or the
like. Non-limiting examples of the thermoplastic resin include
acrylic resin, cellulosic resin, polyester resin, vinyl resin,
rubber type resin, polyamide resin, thermoplastic polyimide
25 resin, polycarbonate resin, liquid crystalline polymer, and
the like.
The micro-protrusion/depression structure including part
(42a-d) can be formed by a coating method. Especially, the
micro-protrusion/depression structure including part (42a-d)
30 can be obtained at a low cost when using wet coating. Further,
- 39 -
a resin coating solution in which the resin is diluted with a
solvent may be used in order to adjust the thickness of the
obtained micro-protrusion/depression structure including part
(42a-d).
5 Alternatively, the micro-protrusion/depression structure
including part (42a-d) can be formed by the following method:
(1) a print-transfer method comprising the steps of
preparing an original plate wherein depressions
corresponding to the inversed shape of a micro10
protrusion/depression structure including part (42a-d) have
been formed,
forming a bonding part (30) onto a carrier substrate (20)
to form a laminated body,
applying a resin coating solution to the depressions of
15 the original plate, and
transferring the resin coating solution applied in the
depressions to the bonding part (30) of the laminated body to
form the micro-protrusion/depression structure including part
(42a-d); and
20 (2) a two-stage transfer method comprising the steps of
preparing a mother plate wherein depressions
corresponding to a micro-protrusion/depression structure
including part (42a-d) have been formed,
forming a bonding part (30) onto a carrier substrate (20)
25 to form a laminated body,
applying a resin coating solution to the depressions of
the mother plate, and
transferring the resin coating solution applied in the
depressions of the mother plate to a support to form an
- 40 -
original plate having an inversed shape of the microprotrusion/
depression structure including part (42a-d),
applying a second resin coating solution to the
depressions of the original plate, and
5 transferring the second resin coating solution applied
in the depressions of the original plate to the bonding part
(30) of the laminated body to form the microprotrusion/
depression structure including part (42a-d).
The print-transfer method (1) may further comprise the
10 step of curing the resin coating solution applied to the
depressions. The two-stage transfer method (2) may further
comprise the step of curing the second resin coating solution
applied to the depressions of the original plate. If the printtransfer
method (1) and two-stage transfer method (2) involving
15 the curing step are used, the micro-protrusion/depression
structure including part (42a-d) is desirably formed from
material selected from the group consisting of thermosetting
resin, oxidative-polymerizable resin, reaction curing resin,
ultraviolet curing resin, and electron beam curing resin. The
20 preferred resin for using in the micro-protrusion/depression
structure including part (42a-d) is the thermosetting resin.
The especially preferred resin is urethane resin and epoxy
resin which are capable of curing at the normal temperature.
The urethane resin is normally obtained by reaction
25 between a "isocyanate-reactive compound" and polyisocyanate.
The polyisocyanate means a compound having at least two
isocyanate groups per molecule. The polyisocyanate comprises
difunctional diisocyanate. Very wide variety of products can
be made, by selection of the isocyanate-reactive compound and
30 polyisocyanate.
- 41 -
The "isocyanate-reactive compound" comprises (a) any
organic compounds having at least two isocyanate-reactive
functionalities per molecule, or (b) imino-functional
compounds. The "isocyanate-reactive functionality" means a
5 functional group containing a Zerewitnoff active hydrogen.
The presence of the Zerewitnoff active hydrogen can be
determined by the method described in E. P. Kohler et al., J.
Am. Chem. Soc., Vol. 49, pp. 3181-3188 (1927) (see NPL1).
Non-limiting examples of the isocyanate-reactive functionality
10 include -COOH, -OH, -NH2, -NH-, CONH2, -SH, and -CONH-. Nonlimiting
examples of the organic compound having at least two
isocyanate-reactive functionalities per molecule include
polyols, polyamines, polymercaptans, and polyacids. Suitable
imino-functional compound is a compound having at least one
15 terminal imino group per molecule. Preferably, the isocyanatereactive
compound is polyol, and more preferably polyether
polyol.
The suitable polyol may be monomers having at least two
hydroxyl groups, oligomers having at least two hydroxyl groups,
20 polymers having at least two hydroxyl groups, and mixtures
thereof. Non-limiting examples of the oligomers and monomers
having at least two hydroxyl groups include castor oil,
trimethylol propane, and diol. The polyol includes branched
diol (for example, 2-n-butyl-2-ethyl-1,3-propanediol)
25 described in International Publication No. WO 98/53013 (see
PTL4).
Examples of polymers suitable as the polyol include
polyester polyol, polyacrylate polyol, polycarbonate polyol,
polyurethane polyol, melamine polyol, and mixtures and hybrids
30 thereof. Such polymers are generally known by those skilled
- 42 -
in the art and commercially available. Non-limiting examples
of the suitable polyester polyol, polyacrylate polyol, and
mixtures thereof are described in International Publication
No. WO 96/20968 and European Patent Laid-Open No. 0688840, for
5 example (see PTL5 and PTL6). Non-limiting examples of the
suitable polyurethane polyol are described in International
Publication No. WO 96/40813 (see PTL7).
Hydroxyl-functional epoxy resin, alkyds, and dendrimeric
polyol described in International Publication No. WO 93/17060
10 may be used as the isocyanate-reactive compound (see PTL8).
Alternatively, the isocyanate-reactive compound may include
potentially hydroxyl-functional compounds. Non-limiting
examples of the potentially hydroxyl-functional compounds
include bicyclic orthoesters (see PTL9), spiro-orthoesters
15 (see PTL9), spiro-orthosilicates (see PTL10), and bicyclic
amideacetals (see PTL11).
The urethane resin composition for forming the microprotrusion/
depression structure including part (42a-d) may
20 further comprise a metal-based catalyst for promoting addition
reaction between the isocyanate group and the isocyanatereactive
group. Such catalyst is known to those skilled in the
art. The catalyst may be present in an amount of generally
from 0.001% to 10% by weight, preferably from 0.002% to 5% by
25 weight, and more preferably from 0.01% to 1% by weight, based
on the non-volatile components of the urethane resin
composition. Suitable metal used in the catalyst includes zinc,
cobalt, manganese, zirconium, bismuth, and tin. The urethane
resin composition preferably comprises a tin-based catalyst.
30 Commonly known examples of the tin-based catalyst include
- 43 -
dimethyltin dilaurate, dimethyltin diversatate, dimethyltin
dioleate, dibutyltin dilaurate, dioctyltin dilaurate, and tin
octoate.
On the other hand, the term "epoxy resin" is a generic
5 name for thermosetting resin capable of curing by formation of
network based on reaction of the epoxy group retained in the
polymer. Typically, the epoxy resin can be obtained by mixing
a prepolymer before curing by polymerization and a curing agent,
followed by thermal curing treatment.
10 The prepolymer may have various composition, but the most
typical one is bisphenol A di(glycidyl ether) which is a
reaction product of bisphenol A and two molecules of
epichlorohydrin. The curing agent includes various polyamine
and acid anhydride.
15 Non-limiting examples of alicyclic epoxy compounds used
for formation of the prepolymer of the epoxy resin include 2-
(3,4-epoxy)cylcohexyl-5,5-spiro-(3,4-epoxy)cyclohexane-mdioxane,
3,4-epoxycyclohexyl-3',4'-epoxycyclohexane
carboxylate (EECH), 3,4-epoxycyclohexylalkyl-3',4'-
20 epoxycyclohexane carboxylate, 3,4-epoxy-6-
methylcyclohexylmethyl, 3',4-epoxy-6'-methylcyclohexane
carboxylate, vinylcyclohexene dioxide, bis(3,4-
epoxycyclohexylmethyl) adipate, bis(3,4-epoxy-6-
methylcyclohexylmethyl) adipate, exo-exo bis(2,3-
25 epoxycyclopentyl)ether, endo-exo bis(2,3-
epoxycyclopentyl)ether, 2,2-bis(4-(2,3-
epoxypropoxy)cyclohexyl)propane, 2,6-bis(2,3-
epoxypropoxycyclohexyl-p-dioxane, 2,6-bis(2,3-
epoxypropoxy)norbornene, diglycidyl ether of linoleic acid
30 dimer, limonene dioxide, 2,2-bis(3,4-epoxycyclohexyl)propane,
- 44 -
dicyclopentadiene dioxide, 1,2-epoxy-6-(2,3-
epoxypropoxy)hexahydro-4,7-methanoindan, p-(2,3-
epoxy)cyclopentylphenyl-2,3-epoxypropyl ether, 1-(2,3-
epopxypropoxy)phenyl-5,6-epoxyhexahydro-4,7-methanoindan, o-
5 (2,3-epoxy)cyclopentylphenyl-2,3-epoxypropyl ether, 1,2-
bis[5-(1,2-epoxy)-4,7-hexahydromethanoindanoxyl]ethane,
cyclopentenylphenyl glycidyl ether, cyclohexanediol diglycidyl
ether, diglycidyl hexahydrophthalate, and mixtures thereof.
Non-limiting examples of aromatic epoxy resin include
10 bisphenol A epoxy resin, bisphenol F epoxy resin, phenol
novolac epoxy resin, cresol novolac epoxy resin, biphenol epoxy
resin, biphenyl epoxy resin, 4,4'-biphenyl epoxy resin,
divinylbenzene oxide resin, 2-glycidylphenyl glycidyl ether
resin, and the like, and mixtures thereof.
15 Non-limiting examples of the curing agent used for curing
the prepolymer of the epoxy resin include acid anhydrides such
as maleic anhydride and copolymer of maleic anhydride, amine
compounds such as dicyandiamide, and phenolic compounds such
as phenol novolac and cresol novolac. Besides, the epoxy resin
20 composition may further comprise a curing accelerator. Nonlimiting
examples of the curing accelerator include imidazoles
and their derivatives, tertiary amines, and quaternary
ammonium salts, and the like.
Radiation curing resin may be used for forming the micro25
protrusion/depression structure including part (42a-d).
Non-limiting examples of the radiation curing resin
include monomers having an ethylenically unsaturated bond,
oligomers having an ethylenically unsaturated bond, and
polymers having an ethylenically unsaturated bond. Non30
limiting examples of the monomers having a radically
- 45 -
polymerizable ethylenically unsaturated bond include 1,6-
hexanediol di(meth)acrylate, neopentyl glycol diacrylate,
trimethylolpropane triacrylate, pentaerythritol triacrylate,
pentaerythritol tetraacrylate, dipentaerythritol
5 pentaacrylate, and dipentaerythritol hexaacrylate. Nonlimiting
examples of radiation curing oligomers include epoxy
acrylate oligomers, urethane acrylate oligomers, and polyester
acrylate oligomers. Non-limiting examples of the radiation
curing polymer include urethane-modified acrylic resin, and
10 epoxy-modified acrylic resin.
Other examples of the radiation curing resin include
photosetting resin described in Japanese Patent Laid-Open No.
S61-98751(1986), Japanese Patent Laid-Open No. S63-23909(1988),
Japanese Patent Laid-Open No. S63-23910(1988), and Japanese
15 Patent Laid-Open No. 2007-118563 (see PTL12 to PTL15). Nonreactive
polymer may be added to the radiation curing resin
composition for the purpose of precise formation of microrelief
pattern. Non-limiting examples of the non-reactive
polymer include acrylic resin, polyester resin, urethane resin,
20 and epoxy resin.
In the case of using cationic polymerization initialized
by radiation such as light, monomers having an epoxy group,
oligomers having an epoxy group, polymers having an epoxy group,
or vinyl ether may be used.
25 A photopolymerization initiator can be added when curing
the above-described radiation curing resin with light such as
ultraviolet light. The polymerization initiator can be
selected dependent on the resin, and may include a radical
photopolymerization initiator, a cationic photopolymerization
30 initiator, or combinations thereof (hybrid type).
- 46 -
Non-limiting example of the radical photopolymerization
initiator include: benzoin-based compounds such as benzoin,
benzoin methyl ether, and benzoin ethyl ether; anthraquinonebased
compounds such as anthraquinone and methylanthraquinone;
5 phenylketone-based compounds such as acetophenone,
diethoxyacetophenone, benzophenone, Michler's ketone,
hydroxyacetophenone, 2-methyl-1-(4-methylthiophenyl)-2-
morpholinopropane-1-one, and benzil dimethyl ketal;
acylphosphine oxides.
10 Non-limiting examples of the cationic
photopolymerization initiator for the case where a
cationically photopolymerizable compound is used include
aromatic diazonium salts, aromatic iodonium salts, aromatic
sulfonium salts, aromatic phosphonium salts, and mixed-ligand
15 metallic salts. In the case of so-called hybrid material in
which radical photopolymerization and cationic
photopolymerization are used in combination, it is possible to
mix and use the respective photopolymerization initiators.
Alternatively, it is also possible to use the aromatic iodonium
20 salts or the aromatic sulfonium salts capable of initiating
the both types of polymerization with one type of initiator.
The polymerization initiator can be added to the resin
composition in an amount from 0.1% to 15% by weight, based on
the non-volatile components of the polymerizable resin
25 composition.
The colorant used for coloration of the microprotrusion/
depression structure including part (42a-d)
includes a dye and a pigment. A plurality of the dyes and/or
pigments may be used in combination. In the case where the
30 translucently colored micro-protrusion/depression structure
- 47 -
including part (42a-d) is formed with the pigment, it is
desirable to use the pigment having a particle diameter of 1
nm to 100 nm, in order to prevent scattering and reflection
due to the pigment particles. Further, in the case where the
5 micro-protrusion/depression structure including part (42a-d)
is formed from a curing resin, it is desirable that the dye
and pigment do not react with active species (free radical,
nucleophile, acid, base, and the like) generated during curing
of the resin. Non-limiting examples of the useful dye include
10 azo dyes. Non-limiting examples of the useful pigment include
phthalocyanine-based pigments, azo-based pigments, and metal
oxides. The colorant is present in an amount of 5% to 50% by
weight, preferably 5% to 30% by weight, based on the nonvolatile
components of the micro-protrusion/depression
15 structure including part (42a-d).
Alternatively, the colorant may be a material which is
excited by ultraviolet light, visible light, or infrared light
to emit fluorescent light or phosphorescent light. It is
possible to impart a special visual effect capable of being
20 detected by visual or mechanical observation, by using the
fluorescent or phosphorescent colorant. Non-limiting examples
of the useful fluorescent colorant include umbelliferone and
rhodamine 6G. Non-limiting examples of the useful
phosphorescent colorant include zinc sulfide, strontium
25 aluminate.
The resin composition used in forming the microprotrusion/
depression structure including part (42a-d) may
further comprise an additive, as desired. Non-limiting
examples of the additive include a polymerization inhibitor,
30 a leveling agent, an anti-foaming agent, an anti-sag agent, an
- 48 -
adhesion promoter, a coated surface modifier, a plasticizer,
a nitrogen-containing compound, metal such as aluminum or
silver, inorganic oxides such as silica and mica, and a
magnetic substance such as magnetite.
5 (Reflective layer (44a-d))
The reflective layer (44a-d) can be formed from metals
such as Al, Sn, Cr, Ni, Cu, Au, and Ag, a metallic compound,
or the like. As used herein, the term "metals" means a simple
substance of metal, or an alloy, and the term "metallic
10 compound" means metallic oxides, metallic sulfides, metallic
halides, metallic nitrides, or the like.
Alternatively, the reflective layer (44a-d) may be formed
by using a transparent material. The transparent material
includes an inorganic compound and organic polymers, for
15 example. Exemplary materials of the inorganic compound and
organic polymers are shown below. Here, in the following
illustration of the material, the figure in parentheses is a
refractive index of each material.
In the case where the reflective layer (44a-d) is formed
20 from the inorganic compound, the useful compound includes
sulfides, chlorides, oxides, and fluorides. Among these
materials, the sulfides have relatively high refractive
indices, and the fluorides have relatively low refractive
indices. Further, the oxides encompass material having from
25 relatively high to relatively low refractive indices. Thus, in
the case where the reflective layer (44a-d) is formed from the
oxides, it is possible to form the reflective layer (44a-d)
having a wide range of the refractive index.
The sulfides useful for forming the reflective layer
30 (44a-d) include CdS (2.6) and ZnS (2.3), for example. The
- 49 -
chlorides useful for forming the reflective layer (44a-d)
include PdCl2 (2.3), for example. The oxides useful for forming
the reflective layer (44a-d) include Sb2O3 (2.0), Fe2O3 (2.7),
TiO2 (2.6), CeO2 (2.3), CdO (2.2), WO3 (2.0), SiO (2.0), Si2O3
(2.5), In2O3 5 (2.0), PbO (2.6), Ta2O3 (2.4), ZnO (2.1), ZrO2
(2.0), MgO (1.6), SiO2 (1.45), Si2O2 (2.0), Al2O3 (1.6), and GaO
(1.7), for example. The fluorides useful for forming the
reflective layer (44a-d) include MgF2 (1.4), CeF3 (1), CaF2
(1.3-1.4), and AlF3 (1.6), for example.
10 In the case where the reflective layer (44a-d) is formed
from the organic polymers, the useful organic polymers include
polyethylene (1.51), polypropylene (1.49),
polytetrafluoroethyelene (1.35) polymethyl methacrylate (1.49),
and polystyrene (1.60), for example.
15 These materials can be appropriately selected based on
optical properties such as the refractive index, a reflective
index, and a transmittance, weathering resistance, interlayer
adhesion, and the like, and formed into a form of a thin film.
In the case where the reflective layer (44a-d) is formed from
20 the transparent material, the difference in refractive index
between the reflective layer (44a-d) and the adjacent layers
(the micro-protrusion/depression structure including part
(42a-d) and the mask layer (46a-d)) is desirably set to not
less than 0.1, preferably not less than 0.5. Sufficient
25 reflectivity can be imparted to the interfaces between the
reflective layer (44a-d) and the adjacent layers, by having
the above-described difference in refractive index.
In the case where the reflective layer (44a-d) is formed
from the metals or metallic compound, commonly known methods
30 such as a vapor deposition method, a sputtering method, and a
- 50 -
CVD method can be appropriately used. Thickness, film-forming
rate, the number of laminated layers, optical thickness and
the like can be controlled by using these methods. Besides,
the film of the above-described metals and metallic compound
5 may be formed so as to cover the whole exposed surface of the
micro-protrusion/depression structure including part (42a-d)
and the bonding part (30), since the reflective layer (44a-d)
will be patterned by etching using the mask layer (46a-d) as
an etching mask as described below.
10 On the other hand, the reflective layer (44a-d) can be
formed by applying fine powders or sol of the above-described
metals, metallic compound, and organic polymers, or a highly
bright light-reflective ink obtained by dispersing metallic
nanoparticles into organic polymer resin. In this case, caution
15 should be exercised so that the micro-protrusion/depression
structure including part (42a-d) is not influenced by the
solvent contained in the ink. The highly bright lightreflective
ink can be applied by a commonly known printing
method such as gravure printing, flexography, and screen
20 printing, or a commonly known coating method such as dip
coating or roll coating. The film made by the printing method
may be formed so as to cover the whole exposed surface of the
micro-protrusion/depression structure including part (42a-d)
and the bonding part (30), since the reflective layer (44a-d)
25 will be patterned by etching in which the mask layer (46a-d)
is used as an etching mask, as described below.

We Claim
1. An optical information medium comprising, in this order:
a bonding part (receiving layer);
5 at least one image part; and
an adhesive layer (protective layer) covering the at
least one image part, wherein:
each of the image part comprises a microprotrusion/
depression structure including part which has
10 a micro-protrusion/depression structure on at least a part
of a surface opposite to the bonding part, a reflective
layer, and a mask layer, in the order from the bonding
part (receiving layer),
the micro-protrusion/depression structure including
15 part is colorless or colored in one or more translucent or
opaque color, and
at least one of the micro-protrusion/depression
structure including part of the image part is colored in
one or more translucent or opaque color.
20
2. The optical information medium according to Claim 1,
wherein the at least one image part is a non-separated
unitary image part.
25 3. The optical information medium according to Claim 1,
wherein the at least one image part is separated two or
more image parts from each other.
4. The optical information medium according to any of Claims
30 1 to 3, wherein the micro-protrusion/depression structure
- 106 -
including part is colorless or colored in one color, in
each of the image part.
5. The optical information medium according to any of Claims
5 1 to 3, wherein the micro-protrusion/depression structure
including part is colored in two or more color, in at least
one of the image part.
6. The optical information medium according to any of Claims
10 1 to 3, wherein the micro-protrusion/depression structure
including part has a peripheral area colored in one color,
and an internal area surrounded by the peripheral area and
colored in one or more color different from the color of
the peripheral area, in at least one of the image part.
15
7. The optical information medium according to any of Claims
1 to 6, wherein the micro-protrusion/depression structure
including part in one of the image part is colored in color
different from the colors of the micro20
protrusion/depression structure including part in the
other image part.
8. The optical information medium according to any of Claims
1 to 7, wherein the mask layer is colorless or colored in
25 one or more colors, in each of the image part.
9. The optical information medium according to Claim 8,
wherein the mask layer in one of the image part is colored
in color different from the colors of the mask layer in
30 the other image part.
- 107 -
10. The optical information medium according to Claim 8 or 9,
wherein the mask layer is colored in two or more color, in
at least one of the image part.
5 11. The optical information medium according to any of Claims
8 to 10, wherein the mask layer has a peripheral area
colored in one color, and an internal area surrounded by
the peripheral area and colored in one or more color
different from the color of the peripheral area, in at
10 least one of the image part.
12. The optical information medium according to any of Claims
1 to 11, wherein the bonding part and the adhesive layer
are colorless.
15
13. The optical information medium according to any of Claims
1 to 11, wherein the adhesive layer is colored in one or
more translucent or opaque colors.
20 14. The optical information medium according to any of Claims
1 to 13, at least two of the image parts has different
area.
15. The optical information medium according to any of Claims
25 1 to 14, wherein the micro-protrusion/depression structure
including part in one of the image part has the microprotrusion/
depression structure different from that of the
micro-protrusion/depression structure including part in
the other image part.
30
- 108 -
16. A transfer leaf comprising:
the optical information medium according to any of
Claims 1 to 15; and
a carrier substrate which is in contact with the
5 bonding part (receiving layer),
wherein it is able to be peeled at an interface between
the bonding part (receiving layer) and the carrier
substrate.
10 17. A label comprising:
the optical information medium according to any of
Claims 1 to 15; and
a removable substrate (peel sheet) being in contact
with the adhesive layer (protective layer),
15 wherein the adhesive layer (protective layer) has
tackiness, and it is able to be peeled at an interface
between the adhesive layer (protective layer) and the
removable substrate (peel sheet).
20 18. A papermaking thread comprising:
the optical information medium according to any of
Claims 1 to 15;
a carrier substrate which is in contact with the
bonding part (receiving layer); and
25 an adhesive layer on the side of the carrier substrate
(second adhesive layer) which is in contact with the
carrier substrate.
19. A laminated body comprising a substrate and the optical
information medium according to any of Claims 1 to 15 which
is attached to the substrate.
20. A printed article comprising: a substrate containing a
printed part in which a printing ink is adhered; and the
optical information medium according to any of Claims 1 to
15 which is attached to the substrate.