0001]This technology relates to electrical transducer and the electro-acoustic converter, in particular, a small and good characteristics, an electro-acoustic transducer and the electroacoustic transducer apparatus which can be kept stable shape.
BACKGROUND
[0002]Conventionally, as one of the audio devices using a piezoelectric material, there is a speaker to form a drive electrodes on both surfaces of the vibrating body hemispherical. Such speakers, piezoelectric polymer film, is a structure which is curved out blistering top than the periphery, piezoelectric speaker electrodes on its both sides is formed has been proposed (e.g., Patent Document 1 reference).
[0003]
　Further, in order to ensure good reproduction frequency characteristics over a wide frequency band, it has been proposed a composite speaker comprising a combination of dynamic speaker and the piezoelectric speaker (e.g., see Patent Document 2).
CITATION
Patent Document
[0004]
Patent Document 1: JP 59-158199 Patent Publication
Patent Document 2: JP 2004-147077 JP
Summary of the Invention
Problems that the Invention is to Solve
[0005]
　However, in the above-described technique, a small and good characteristics, shape it has been difficult to obtain a stable speaker.
[0006]
　For example, in the piezoelectric speaker described in Patent Document 1, since the piezoelectric polymer film is a film material is soft, the shape of the piezoelectric polymer film portion is unstable, depression due easily user operation when viewed as a commodity It would give rise to the appearance of damage.
[0007]
　Further, in the composite speaker described in Patent Document 2, since it contains the dynamic speaker, thinner becomes difficult, which is one of the advantages of the piezoelectric speaker.
[0008]
　This technology has been made in view of such circumstances, a small and good characteristics, it is desirable to make it possible to maintain a stable shape.
Means for Solving the Problems
[0009]
　Electro-acoustic transducer of the first aspect of the present technology, made from a sheet-like piezoelectric material, a first sheet having a curved shape, a first sheet and substantially the same shape, the first sheet superposed by and a second sheet arranged.
[0010]
　The second sheet can be nonwoven.
[0011]
　The electro-acoustic transducer, a first sheet and substantially the same shape, wherein the second sheet from the first sheet side arranged superimposed on the opposite side consist of a sheet-like piezoelectric material It may further include a third sheet.
[0012]
　The second sheet may be a piezoelectric material.
[0013]
　The second sheet may be as is bonded to the first sheet.
[0014]
　Said first sheet and said second sheet, the pressing portion provided at an end portion of said first sheet and said second sheet, it is pressed is sandwiched between the frame fixing member and the frame base it can be made to be fixed by.
[0015]
　Wherein the frame fixing member and the frame base has an opening exposing the first sheet and the second sheet can be so provided.
[0016]
　Wherein one frame fixing member and at least one of said frame base, when said frame fixing member and the frame base is viewed from a first direction substantially perpendicular to the second direction arranged, the first direction it can be made to taper portion is formed so that the width of the opening changes with respect.
[0017]
　The tapered portion may be so the first width of the first sheet and the farther position from the second sheet opening in direction is formed to be wider.
[0018]
　The tapered portion may be so the first said in the direction of the first sheet and the second width of the opening from the seat farther position is formed to be narrower.
[0019]
　In the first aspect of the present technique, the electro-acoustic transducer, made from a sheet-like piezoelectric material, a first sheet having a curved shape, a first sheet and substantially the same shape, the first a second sheet arranged in superposed sheets are provided.
[0020]
　Electro-acoustic converter of the second embodiment of the present technology, made from a sheet-like piezoelectric material, a first sheet having a curved shape, and a said first sheet and substantially the same shape, the first sheet a first electro-acoustic transducer having a second sheet disposed superposed, which is connected in parallel with the first electro-acoustic transducer, said first and said first electro-acoustic transducer and a second electroacoustic transducer area of ​​the sheet and the second sheet are different.
[0021]
　Wherein the first electro-acoustic transducer and electro-acoustic transducer for the low frequency of said second electro-acoustic transducer, for adjusting the frequency characteristic to protect the electro-acoustic transducer for the low frequency can protect adjustment unit is so connected.
[0022]
　The protective adjustment unit may be a protection resistor or a low-pass filter.
[0023]
　In the second aspect of the present technology, the electroacoustic transducer, made from a sheet-like piezoelectric material, a first sheet having a curved shape, and a said first sheet and substantially the same shape, the first a first electro-acoustic transducer having a second sheet disposed superposed sheets, is connected in parallel with said first electro-acoustic transducer, wherein the first electro-acoustic transducer said first the first sheet and the area of ​​the second sheet is provided with a different second electro-acoustic transducer.
Effect of the invention
[0024]
　According to the first aspect and the second aspect of the present technology, a small and good characteristics, it is possible to maintain a stable shape.
[0025]
　Here, the advantages described in the present invention is not necessarily limited, it may be any of the effects described in the present disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026]
FIG. 1 is a perspective view showing an example of the external configuration of the piezoelectric audio device.
FIG. 2 is a side view showing an example of the external configuration of the piezoelectric audio device.
3 is a perspective view showing an example of configuration of another appearance of a piezoelectric audio device.
4 is a sectional view showing another example of the configuration of a piezoelectric audio device.
Is a diagram illustrating FIG. 5 electrode wiring.
6 is a diagram showing an example of the external configuration of the piezoelectric audio device.
7 is a diagram showing a circuit configuration example of a piezoelectric audio device.
8 is a graph showing the frequency characteristic of the piezoelectric audio device.
9 is a graph showing the frequency characteristics of the piezoelectric audio device for the high-frequency low-band.
10 is a diagram showing the impedance characteristics of the piezoelectric audio device for the low frequency.
11 is a flowchart for explaining a manufacturing process.
12 is a diagram showing an example of a process of manufacturing the piezoelectric audio device.
13 is a diagram showing an example of a process of manufacturing the piezoelectric audio device.
DESCRIPTION OF THE INVENTION
[0027]
　Hereinafter, with reference to the accompanying drawings, a description will be given of an embodiment according to the present technology.
[0028]

　The present technique includes a curved acoustic sheet obtained by bending a sheet-like piezoelectric device, a reinforcing sheet for the curved acoustic sheet and substantially the same shape superposed by a electro-acoustic transducer, a small and good characteristics, it is desirable to make it possible to retain a stable shape.
[0029]
　Hereinafter, as an example of the embodiment to which the present technology is applied, will be described piezoelectric audio devices and piezoelectric audio device, those embodiments are illustrative embodiment adopted in accordance with the present technology, the technology is not to be limited interpreted based on the specific matters to those embodiments.
[0030]
　1 and 2 are diagrams showing an example of the external configuration of the piezoelectric audio device according to the present technology. That is, FIG. 1 is a perspective view of a piezoelectric audio device to which the present technology is applied, FIG. 2 is a side view of the piezoelectric audio device according to the present technology. In FIGS. 1 and 2 are denoted with the same reference numerals correspond to each other, and a description thereof will be omitted as appropriate.
[0031]
　First, referring to FIGS. 1 and 2, will be described piezoelectric audio device according to the present technology. Piezoelectric audio device 11 shown in FIGS. 1 and 2, and vibrates according to an electric signal as an input acoustic signal, the electro-acoustic transducer for converting acoustic signals into sound, that is, the speaker unit.
[0032]
　Piezoelectric audio device 11 has a curved acoustic sheet 21, the reinforcing sheet 22, the frame ring 23 and the frame base 24,.
[0033]
　In this example, in FIG. 1, the upper, i.e. the frame ring 23 side has been adapted to the curved acoustic sheet 21 is exposed, when the frame ring 23 side to reproduce the sound, the sound by a piezoelectric audio device 11 and has a side that is emitted. Hereinafter, the surface on the side where the sound of the piezoelectric audio device 11 is radiated, that is, the surface of the exposed and has the side of the curved acoustic sheet 21, particularly also referred to as a radiation surface.
[0034]
　Further, in the piezoelectric audio device 11, in FIG. 2, the lower side, that are adapted to the reinforcing sheet 22 is exposed when viewed from the frame base 24 side, the surface on the side of the reinforcing sheet 22 is exposed emitting surface which faces, that is, a surface opposite to the emitting surface.
[0035]
　Curved acoustic sheet 21, for example as a material of the sheet-shaped piezoelectric device having a sound effect, one obtained by bending the piezoelectric device by a molding process as a part of a three-dimensional shape having a depth d is there. That is, the curved shape of the molded piezoelectric device, that is, the portion having a three-dimensional shape has a curved acoustic sheet 21. Further, the piezoelectric device constituting the curved acoustic sheet 21 on both sides of a sheet-like piezoelectric material is a structure in which a sheet-shaped electrode. Further, a cover layer for protecting the electrodes as required in the piezoelectric device are provided.
[0036]
　A piezoelectric audio device 11 in this example when viewed from the radiation surface side, the curved acoustic sheet 21 has a concave shape which is collision opposite side of the emission surface side, in particular curved acoustic sheet 21 It was obtained a sphere of radius r cut by a plane, and has a spherical cap shape with a depth d.
[0037]
　Here, for example, the depth d is about 5 mm. For example, to reduce the depth d of the spherical crown shape in the bending acoustic sheet 21, it is possible to improve the frequency characteristics of the low band portion of the piezoelectric audio device 11. Moreover, the curvature or the like of the shape of the curved acoustic sheet 21, it is possible to adjust the directivity of the sound reproduced by the piezoelectric audio device 11.
[0038]
　Further, for example, a piezoelectric material constituting the curved acoustic sheet 21 has a flexible sheet shape, are such as a polymer composite piezoelectric body is dispersed polymeric ceramic. Such a piezoelectric material is to shrink or stretch in response to the polarity when voltage is applied, to realize an acoustic conversion by expanding and contracting bending the bending acoustic sheet 21 utilizing the piezoelectric material (vibration) can.
[0039]
　Property that converts electrical energy and mechanical energy is called the piezoelectric effect, in order to have the piezoelectric effect needs to preliminarily subjected to polarization processing to the piezoelectric material. And polarization treatment is a treatment to impart polar align the direction of spontaneous polarization by applying a DC high voltage to the ceramic under e.g. high temperatures.
[0040]
　Hereinafter, the other curved acoustic sheet which will be described later and curved acoustic sheet 21 and those previously polarization process is performed. For example curved acoustic sheet 21 is assumed to be a state in which the polarization processing has been performed at the stage before molding is carried out.
[0041]
　Reinforcing sheet 22, a sheet-like member, in which a part is obtained by bending the molding process so as to have substantially the same shape as the curved acoustic sheet 21. That is, the curved shape of the molded member, that is, the portion having a three-dimensional shape and has a reinforcing sheet 22.
[0042]
　Therefore, even concave reinforcing sheet 22, and specifically obtained by cutting by a plane, for example, of radius r sphere, it has a spherical cap shape with a depth d.
[0043]
　Reinforcing sheet 22, for example, different from the piezoelectric device, made of a material having no acoustic effect. More specifically, the reinforcing sheet 22 made of nonwoven fabric. Incidentally, the description will be continued assuming that the reinforcing sheet 22 is made of non-woven fabric in the following.
[0044]
　For example, in a piezoelectric audio device 11, the reinforcing sheet 22 in the bending acoustic sheet 21 are bonded with an adhesive or the like is superimposed on the surface opposite to the emitting surface.
[0045]
　By thus arranging overlapping the reinforcing sheet 22 relative to the curved acoustic sheet 21, as the hardness of the surface of the curved shape and the curved acoustic sheet 21 combined reinforcing sheet 22, and any desired hardness can be controlled, it is possible to control the loss of sound pressure. Specifically, it is possible to reduce the peaks and dips in the frequency characteristic of the example, a piezoelectric audio device 11.
[0046]
　Furthermore, in the piezoelectric audio device 11, since the output sound by vibrating the curved acoustic sheet 21 made of a piezoelectric material, small and, in other words it is possible to ensure good reproduction frequency characteristics is thin, and over a wide frequency band. In particular, by providing overlapping the reinforcing sheet 22 relative to the curved acoustic sheet 21, the shape is not only stable, it is possible to obtain better frequency characteristics as compared with the case where only the curved acoustic sheet 21.
[0047]
　Furthermore, the curved acoustic sheet 21 and the reinforcing sheet 22, the pressing portion 25 of the substantially ring shape provided integrally with them is provided.
[0048]
　That is, the not be curved acoustic sheet 21 portion of the molded processed piezoelectric device, and not the reinforcing sheet 22 portion in molding nonwoven has a pressing portion 25. Thus, in this example, the holding section 25 is set along the end portion curved acoustic sheets 21 and integrally with the reinforcing sheet 22 of the curved acoustic sheet 21 and reinforcing sheet 22, i.e. is formed continuously.
[0049]
　For example, during the manufacture of the piezoelectric audio device 11, the piezoelectric device and the nonwoven sheet is superposed is adhered with an adhesive or the like, bending is simultaneously molding on those piezoelectric device and the nonwoven fabric is performed acoustic sheet 21, the reinforcing sheet 22, and the pressing portion 25 is formed.
[0050]
　Note that the piezoelectric device sheet to be curved acoustic sheet 21, when performing the forming process relative to the sheet-like nonwoven fabric comprising the reinforcing sheet 22, it is necessary to bond the piezoelectric device and the nonwoven fabric in the process. Therefore, for example, during the molding process, whereas one of the piezoelectric device and the nonwoven fabric, or adhesive in both of them are applied. Other, for example non-woven fabric in advance by applying a thermoplastic adhesive to, may be able to adhere to the curved acoustic sheet 21 in the molding process.
[0051]
　Molding process of bending the acoustic sheet 21 and reinforcing sheet 22 is, for example other pressure molding, press molding, vacuum molding, may be of any type, so that the molding is carried out by a method which combines a plurality of molding methods it may be.
[0052]
　Also, here is arranged curved acoustic sheet 21 on the radiation surface side, its the emission surface side of the curved acoustic sheet 21 will be described an example in which the reinforcing sheet 22 on the opposite side are disposed, reinforcing the radiation face side sheet 22 There is arranged, it may be disposed curved acoustic sheet 21 on the side opposite to the emission surface side of the reinforcing sheet 22. Even in such a case, it suffices to adhesive is applied on at least one of the piezoelectric device and the nonwoven fabric.
[0053]
　The curved acoustic sheet 21, the electrode portions 26-1 and the electrode 26-2 for extracting the electrodes are connected.
[0054]
　For example the electrode portions 26-1 is connected to the electrode provided on the emitting surface side of the piezoelectric device constituting the curved acoustic sheet 21, the emitting surface side of the piezoelectric device electrode portion 26-2 constituting the curved acoustic sheet 21 It is connected to the electrode provided on the opposite side of the. These electrodes 26-1 and the electrode 26-2 is connected to the amplifier via the example audio signal line.
[0055]
　By thus providing the electrode portions 26-1 and the electrode 26-2, it is possible to easily connect the piezoelectric audio device 11 and the playback control apparatus. In the following description, when it is necessary to distinguish the electrode portions 26-1 and the electrode 26-2, simply referred to also referred to as the electrode portion 26.
[0056]
　Here, there will be described a case where two electrode portions 26 are disposed adjacent to each other, these electrodes 26, for example, left and right edges, position or the like away from each other, be placed in any position it can. This also applies to the electrode portion connected to the curved acoustic sheet described later.
[0057]
　Frame rings 23 and the frame base 24, the central portion is formed from a ring-shaped member which is hollowed out in a circular shape, these flame ring 23 and the frame base 24, the curved acoustic sheet 21 and reinforcing sheet 22 is fixed ing.
[0058]
　That is, in the piezoelectric audio device 11, a frame ring 23 are arranged such pressing portion 25 and the electrode portion 26 is sandwiched between the frame base 24. The flame ring 23 by fasteners 27 are pressed against the frame base 24, thereby bending the acoustic sheet 21 and reinforcing sheet 22 is fixed to the frame base 24.
[0059]
　Incidentally, the holding section 25, may be formed to have a width enough to be able to press the curved acoustic sheet 21 and reinforcing sheet 22 suitably. However, for example, the width of the holding portion 25, i.e. when the area required minimum area of ​​the pressing portion 25, it is possible to suppress the influence by a decrease in the impedance of the piezoelectric audio device 11 in the reproduction of the super high frequency band occurs.
[0060]
　Other, for example, the width of the holding portion 25, may be the entire surface of the flame ring 23 and side abutting the frame base 24 is covered with the pressing portion 25.
[0061]
　Thus the flame ring 23 and the frame base 24 by fixing the holding portion 25 can hold the molded shape of the curved acoustic sheet 21 and reinforcing sheet 22 more stably. The fixing member for fixing the curved acoustic sheet 21 and reinforcing sheet 22 is not limited to a circular shape shown in the frame ring 23 and the frame base 24 may be of any type rectangular frame-shaped member or the like.
[0062]
　The central of hollowed portion of the frame ring 23 as shown in FIG. 1 has an opening portion 28 for exposing the entire curved acoustic sheet 21 on the emission surface side. In Figure 1 the openings 28, the lateral width in the figure of the curved acoustic sheet 21 is formed to be wider than or equal to the lateral width.
[0063]
　Similarly, the center of hollowed portion of the frame base 24, as shown in FIG. 2 has an opening portion 29 for exposing the entire reinforcing sheet 22 on the side opposite to the emission surface side. In Figure 2 the opening 29, the lateral width in Figure 2 of the reinforcing sheet 22, and is formed to have a lateral width substantially equal.
[0064]
　Further, the flame ring 23 and the frame base 24, a tapered portion for adjusting the frequency characteristic of the piezoelectric audio device 11 is provided.
[0065]
　For example, as shown in FIG. 1, the tapered portion 30 is formed in an edge portion of the frame ring 23. Further, the tapered portion 31 is formed in the edge portion of the frame base 24, as shown in FIG.
[0066]
　These tapered portions 30 and the tapered section 31 can control influence on acoustic (sound) emitted from the curved acoustic sheet 21 or the like which is fixed by the frame ring 23 and the frame base 24, i.e., the frequency characteristic.
[0067]
　For example the tapered portion 30, as along the inner edge of the frame ring 23 is formed in a curved acoustic sheet 21 near the portion in the frame ring 23.
[0068]
　Then, in FIG. 2 the frame ring 23, when viewed in the depth direction, that is, when viewed frame ring 23 from the frame ring 23 and the frame base 24 and are aligned direction substantially perpendicular, in FIG. 2, vertical in Figure 2 the opening 28 with respect to the direction, the tapered portion 30 as the lateral width is changed is formed.
[0069]
　In particular, where in FIG. 2, the more distant from the curvature in the longitudinal direction acoustic sheet 21, in Figure 2 the opening 28, the tapered portion 30 as the lateral width becomes wider is formed.
[0070]
　In other words, the frame base 24 side of the frame ring 23, the inner diameter of the frame ring 23 is small, the inner diameter of the flame ring 23 toward the opposite side is larger than the frame base 24 side. Hereinafter, it is assumed that a tapered structure such as width of the position as the opening of a curved acoustic sheet 21 and reinforcing sheet 22 side becomes smaller (narrower) also referred to as forward tapered structure.
[0071]
　On the other hand, the tapered portion 31 as shown in FIG. 2, as along the inner edge of the frame base 24, is formed in a portion near the reinforcement sheet 22 in the frame base 24.
[0072]
　In Figure 2 the frame base 24, when viewed in the depth direction, that is, when viewed frame base 24 from the frame ring 23 and the frame base 24 and are aligned direction substantially perpendicular, in FIG. 2, in the longitudinal direction in Figure 2 the opening 29 against the tapered portion 31 as the lateral width is changed is formed.
[0073]
　In particular, here in FIG. 2, the more distant from the vertical reinforcing in the direction the sheet 22, in Figure 2 the opening 29, the tapered portion 31 so that the width in the horizontal direction is narrowed is formed.
[0074]
　In other words, the frame ring 23 side of the frame base 24, the inner diameter of the frame base 24 is large, the inner diameter of the frame base 24 toward the opposite side is smaller than the frame ring 23 side. Hereinafter, it is assumed that a tapered structure such as width of the position as the opening of a curved acoustic sheet 21 and reinforcing sheet 22 side becomes larger (wider) also referred to as reverse taper structure.
[0075]
　Thus the flame ring 23 and the frame base 24 to form a tapered portion by a tapered structure, it is possible to adjust the degree of exposure to air in the vicinity of the surface of the curved acoustic sheet 21 and reinforcing sheet 22. This makes it possible to adjust to the desired frequency characteristics.
[0076]
　Incidentally, the tapered portion 30 and tapered portion 31, the frame ring 23 and the frame base 24 if so can be suppressed pressing portion 25 may be any structure.
[0077]
　In addition, here will be described a configuration in which a tapered portion is provided on both the frame ring 23 and the frame base 24 as an example, either only one of the frame ring 23 and the frame base 24 may be tapered portion is provided and, may be tapered portion is not provided in any of the frame ring 23 and the frame base 24.
[0078]
　Moreover, tapered structure of the tapered portion 30 and tapered portion 31 may be either a forward tapered structure opposite tapered structure. In particular, when the tapered portion 30 and a forward tapered structure, the tapered portion 31 and the inverted tapered structure, it is possible to obtain a good frequency characteristic. At this time, a part of the pressing portion 25 may not be pressed by the frame ring 23 and the frame base 24.
[0079]
　Piezoelectric audio device 11 as described above operates as an electric signal as an acoustic signal from the electrode unit 26 is supplied, it outputs a sound corresponding to the acoustic signal. That is, when an acoustic signal is supplied, the curved acoustic sheet 21 vibrates in response to sound signals, which sound is reproduced by.
[0080]
　Here, as a material constituting the curved acoustic sheet 21, the sensitivity will be described regarding sound pressure of a piezoelectric audio device 11 in the case of using a flexible piezoelectric material.
[0081]
　Curved acoustic sheet 21 by applying the molding is a curved surface shape, the sensitivity of the sound pressure of a piezoelectric audio device 11 having a piezoelectric effect is related to the area and thickness of solely curved acoustic sheet 21 portion.
[0082]
　That is, to follow the expression capacity of the common capacitor C, a larger area of ​​the curved acoustic sheet 21 portion, also towards the thickness of the curved acoustic sheet 21 portion is thin it is possible to improve the sensitivity. In other words, it is possible to obtain a larger sound pressure even when the same voltage is applied.
[0083]
　For example will improve the sensitivity of the piezoelectric audio device 11, when trying to obtain a desired sound pressure, to increase the area of ​​the curved acoustic sheet 21 portion, and a thinner thickness of the curved acoustic sheet 21 parts it is both will reduce the stability of the shape of the curved acoustic sheet 21 portion.
[0084]
　Therefore, in the piezoelectric audio device 11, for example, differs from the reinforcing sheet 22 and the curved acoustic sheet 21, made of a material such as a nonwoven fabric having no sound effect, a curved acoustical sheet 21 reinforcing sheet 22 are arranged superimposed . Thus, while improving the sensitivity of the piezoelectric audio device 11, it is possible to enhance the retention of the shape of the molded curved acoustic sheet 21. Further, without using a dynamic speaker or the like, a small, i.e. it is possible to obtain a piezoelectric audio device 11 having good frequency characteristics in thin.
[0085]
　As described above, in the piezoelectric audio device 11, a bending acoustic sheet 21 made of a piezoelectric material, by disposing superposed reinforcing sheet 22 made of nonwoven fabric, a small and good frequency characteristics, an electro-acoustic shape is stabilized it can be obtained transducer.
[0086]

　In the above, the curved acoustic sheet 21 and reinforcing sheet 22 is in a concave shape that is collision on the side opposite to the emission surface side It has been described for an example. However, the curved acoustic sheet 21 and reinforcing sheet 22, for example, as shown in FIG. 3 may be a convex shape that is collision on the emission surface side. Note that portions corresponding to the case in FIG. 1 in FIG. 3 are denoted by identical reference numerals, and description thereof will be omitted as appropriate.
[0087]
　Figure 3 is a perspective view showing another example of the configuration of a piezoelectric audio device according to the present technology. Piezoelectric audio device 61 shown in FIG. 3, the curved acoustic sheet 21, the reinforcing sheet 22, and a frame ring 23 and the frame base 71,. Incidentally, in the figure in the reinforcement sheet 22 is curved acoustic sheet 21, since it is arranged being overlaid below, the reinforcing sheet 22 in FIG. 3 in a state invisible hidden curved acoustic sheet 21.
[0088]
　In the piezoelectric audio device 61, in the figure, the upper has a radiation surface side, the curved acoustic sheet 21 and the reinforcing sheet 22, the pressing portion 25 provided at their end portions is a frame ring 23 and the frame base 71 and it is fixed by being pressed by.
[0089]
　In Figure 3, the curved acoustic sheet 21 and the reinforcing sheet 22, in the figure, has a convex shape which is collision upward, curving specifically acoustic sheet 21 and the reinforcing sheet 22, the plane sphere of radius r taken obtained, it has a spherical cap shape with a depth d.
[0090]
　Further, in the piezoelectric audio device 61, the outer shape of the frame base 71 is a rectangular parallelepiped shape, the frame ring 23 is pressed against a portion of the surface of the radiating surface side of the frame base 71, a frame ring 23 by fasteners 27 It is fixed to the frame base 71. That is, the surface of the radiating surface side of the frame base 71 in this example is wider than the whole frame ring 23. Furthermore, the frame base 71 is also formed tapered portion corresponding to the tapered portion 31.
[0091]
　Or shape of the curved acoustic sheet 21 and reinforcing sheet 22 as may be any shape as long as the curved shape.
[0092]
　For example the shape of the curved acoustic sheet 21 and reinforcing sheet 22, other cross section becomes substantially rectangular square shape or the like, and may be a crown shape having a depth d. Further, for example, the shape of the curved acoustic sheet 21 and reinforcing sheet 22 is a spherical zone shape which is a portion of a sphere of radius r1 portion opposite to the predetermined and the radiation face side, part of the radiation surface than the portion There may be a complex three-dimensional shape, such a combination of spherical zone and crown such that the spherical crown shape which is a part of a sphere of radius r2 (curved shape).
[0093]
　When properly adjusted the shape of the curved acoustic sheet 21 and reinforcing sheet 22, it is possible to adjust the sound quality of the sound obtained by the piezoelectric audio device.
[0094]

　Furthermore, the piezoelectric audio device 11 in the above, the example in which two sheets of curved acoustic sheet 21 and reinforcing sheet 22 is provided for a description did. However, the piezoelectric audio device, so that three or more sheets of substantially the same shape superimposed one another are provided, at least one of those 3 or more sheets but so as to be curved acoustic sheet having an acoustic effect it may be.
[0095]
　In such a case, for example, a piezoelectric audio device 11 is configured as shown in FIG. Note that portions corresponding to the case in FIG. 1 or FIG. 2 in FIG. 4 are given the same reference numerals, and description thereof will be omitted as appropriate.
[0096]
　Figure 4 shows a cross-sectional view of the piezoelectric audio device 11 when the three sheets are provided. In this example, configuration of the piezoelectric audio device 11, the piezoelectric audio device 11 shown in FIGS. 1 and 2, has a more curved acoustic sheet 101 is provided configured. That is, in the piezoelectric audio device 11 shown in FIG. 4, the curved acoustic sheet 21 as three sheets, the reinforcing sheet 22, and a curved acoustic sheet 101 is provided, the curved acoustic sheet 21 and the reinforcing sheet 22, FIG. 1 and FIG. It has the same shape as the example shown in 2.
[0097]
　In this example, in the figure, the upper has a radiation surface side, are arranged reinforcing sheet 22 is superimposed on the side opposite to the emission surface side of the curved acoustic sheet 21. Further, the radiation face side of the reinforcing sheet 22, that is, the curved acoustic sheet 21 side are arranged curved acoustic sheet 101 is superimposed on the other side. Then, these curved acoustic sheet 21, the reinforcing sheet 22 and the curved acoustic sheet 101, is substantially a same shape. From such an arrangement, the piezoelectric audio device 11 of FIG. 4, the opening 29 side are made so that the entire curved acoustic sheet 101 is exposed.
[0098]
　Curved acoustic sheet 101, for example as a material for piezoelectric devices like sheet having an acoustic effect, which was obtained by bending the piezoelectric device by a molding process as a part of a three-dimensional shape having a depth d is there. The piezoelectric device as a curved acoustic sheet 101 has a structure in which a respective electrode on both surfaces of the piezoelectric material. Further, a cover layer for protecting the electrodes as required in the piezoelectric device are provided.
[0099]
　In FIG. 4 of the piezoelectric audio device 11, and not a curved acoustic sheet 21 portion of the molded processed piezoelectric device, and not the reinforcing sheet 22 portion in molding nonwoven, curved acoustic sheet 101 in the molded processed piezoelectric device and a is not part has a pressing portion 25. Then, the pressing portion 25 is pressed is sandwiched between the frame ring 23 and the frame base 24, thereby bending the acoustic sheet 21, the reinforcing sheet 22, and a curved acoustic sheet 101 is fixed to the frame base 24.
[0100]
　Curved acoustic sheet 21, the reinforcing sheet 22, and the molding process of the curved acoustic sheet 101, the curved acoustic sheet 21, the reinforcing sheet 22, and it is necessary to bend the acoustic sheet 101 are bonded to each other. Therefore, in the molding process, for example, adhesive is applied to both sides of the reinforcing sheet 22, with the curved acoustic sheet 21 and reinforcing sheet 22 is bonded, curved acoustic sheet 101 and the reinforcing sheet 22 are also bonded. Other, for example, the reinforcing sheet 22 in advance by applying a thermoplastic adhesive, bending the acoustic sheet 21 in the molding process, may be allowed to adhere reinforcing sheet 22, and a curved acoustic sheet 101 simultaneously.
[0101]
　As described above, substantially the same shape of the curved acoustic sheet 21, also by arranging superimposed reinforcing sheet 22 and the curved acoustic sheet 101, similarly to the piezoelectric audio device 11 shown in FIG. 1, a small and excellent frequency characteristics in, it is possible to shape obtain stable electro-acoustic transducer.
[0102]
　Although the curved acoustic sheet 21 is curved acoustic sheet 101 is obtained in advance polarization treatment, the electrode wiring of these curved acoustic sheet 21 and the curved acoustic sheet 101, for example as indicated by an arrow Q11 and arrow Q12 in FIG. 5 it can be a Do wiring. In FIG. 5, portions corresponding to the case in FIG. 4 are given the same reference numerals, and description thereof will be omitted as appropriate.
[0103]
　In the example shown in FIG. 5, the curved acoustic sheet 21 and the piezoelectric material 131, and a electrode 132 and the electrode 133 provided on both surfaces of the piezoelectric material 131. In particular, the electrode 132 in this example is connected to the electrode portions 26-1 shown in FIG. 1, the electrode 133 is connected to the electrode portions 26-2 shown in FIG.
[0104]
　Similarly, curved acoustic sheet 101 and the piezoelectric material 134, and a electrode 135 and the electrode 136. provided on both surfaces of the piezoelectric material 134.
[0105]
　In the piezoelectric audio device 11 shown in FIG. 4, a curved piezoelectric device has been used as an acoustic sheet 21 and the curved acoustic sheet 101, it is necessary to withdraw the electrodes from each side of their piezoelectric device.
[0106]
　Further, in the piezoelectric audio device 11 shown in FIG. 4, the curved acoustic sheet 21, the reinforcing sheet 22 and the curved acoustic sheet 101, has an uneven because they are molded integrally, both in the same direction.
[0107]
　Now, for example, as shown by the arrow Q11 in FIG. 5, the acoustic signal supplied to the curved acoustic sheet 21 and the curved acoustic sheet 101 is a normal phase Electrode 132 and electrode 133, normal phase also electrode 135 and the electrode 136 and it is. In this case, the electrode 132 and electrode 135 is + side electrode, the electrode 133 and electrode 136 is a ground-side (hereinafter, also referred to as G side), that is - a side electrode.
[0108]
　Therefore, + with connecting electrode 132 side to each other and the electrode 135, by connecting the electrode 133 and the electrode 136 of the G side each other in both the electroacoustic transducer output the figure, upward or downward the same direction that. That is, the curved acoustic sheet 101 vibrates in the same direction as the curved acoustic sheet 21. Thus, it is possible to improve the sound pressure of the reproduced sound.
[0109]
　Further, as shown by the arrow Q12, the acoustic signal supplied to the curved acoustic sheet 21 and the curved acoustic sheet 101, although the electrodes 132 and the electrode 133 is a normal phase, is opposite phase for the electrodes 135 and the electrode 136 to. In this case, since the reverse-phase positive side and G side and is replaced, it is the electrode 132 and the electrode 136 is + side electrode, the electrode 133 and the electrode 135 is G-electrode.
[0110]
　Therefore, + with connecting electrode 132 side to each other and the electrode 136, by connecting the electrode 133 and the electrode 135 of the G side each other in both the electroacoustic transducer output the figure, upward or downward the same direction that. That is, the curved acoustic sheet 101 vibrates in the same direction as the curved acoustic sheet 21. Thus, it is possible to improve the sound pressure of the reproduced sound.
[0111]
　By connecting in this way the curved acoustic sheet 21 of the electrode of the curved acoustic sheet 101, the curved acoustic sheet 21 is molded, the reinforcing sheet 22, and together with the shape of the curved acoustic sheet 101 can be more stably hold the , it is possible to improve the sensitivity of the sound pressure.
[0112]
　In the piezoelectric audio device 11 shown in FIG. 4, although the reinforcing sheet 22 between the curved acoustic sheet 101 and the curved acoustic sheet 21 has been described the example provided, the reinforcing sheet 22 is not provided, the curved acoustic sheet 21 curved acoustic sheet 101 may be provided superimposed such that adjacent to each other. Surface of the electrode provided on the curved acoustic sheet 21 and bending the acoustic sheet 101 because it is insulated, the characteristics and operation of the piezoelectric audio device 11 be superimposed curved acoustic sheet 101 and these curved acoustic sheet 21 directly It does not occur impact on.
[0113]
　The reinforcing sheet 22 is not provided as, also be curved acoustic sheet 101 and the curved acoustic sheet 21 is provided, a shape by overlapping the curved acoustic sheet 21 and the curved acoustic sheet 101 can be stabilized. Accordingly, a small and good frequency characteristics, shape can be obtained a stable electro-acoustic transducer. In this case, it is possible for example by means of an adhesive or the like and a piezoelectric material constituting the curved acoustic sheet 21 and the piezoelectric material constituting the curved acoustic sheet 101 at the stage of pre-treatment before molding, to such bonded.
[0114]

　Next, the present technology, embodiments applied to a piezoelectric audio device having a plurality of piezoelectric audio device described in the above will be described.
[0115]
　Figure 6 is a diagram showing an example of the external configuration of the piezoelectric audio device according to the present technology.
[0116]
　Piezoelectric audio device 201 shown in FIG. 6 vibrates according to an electric signal as an input acoustic signal, the electro-acoustic converter for converting an acoustic signal into sound, i.e. a speaker (speaker system).
[0117]
　In this example, a piezoelectric audio device 201 is a piezoelectric audio device 211, a piezoelectric audio device 212-1, a piezoelectric audio device 212-2 has a frame 213, and the base 214.
[0118]
　In the piezoelectric audio device 201, the plate-like frame 213, three piezoelectric audio device 211 corresponding to the piezoelectric audio device 11 shown in FIG. 1, a piezoelectric audio device 212-1, and a piezoelectric audio device 212-2 is provided ing.
[0119]
　Further, in the figure in the frame 213, and base 214 is fixed to the lower, are made to be able to piezoelectric audio device 201 is self-supporting by the base 214.
[0120]
　Piezoelectric audio device 211 is, for example, the same structure as the piezoelectric audio device 11 shown in FIG. 1, a speaker unit for high-range, especially for reproducing sound of the high frequency band.
[0121]
　In contrast, the piezoelectric audio device 212-1 and a piezoelectric audio device 212-2, for example, the same structure as the piezoelectric audio device 11 shown in FIG. 1, in particular for reproducing sound of the low frequency band of a speaker unit for the low frequency.
[0122]
　In the following description, when it is necessary to distinguish the piezoelectric audio device 212-1 and a piezoelectric audio device 212-2, simply and also referred to as a piezoelectric audio device 212.
[0123]
　Here, the piezoelectric audio device 211 for high-frequency, but have the same structure as the piezoelectric audio device 212 for the low frequency, the area of ​​the curved acoustic sheet and the reinforcing sheet of the piezoelectric audio device 211 for high band is It is smaller than the area of ​​the curved acoustic sheet and the reinforcing sheet of the piezoelectric audio device 212 for the low frequency. In other words, the size of the piezoelectric audio device 211 is smaller than the size of the piezoelectric audio device 212.
[0124]
　Here, the curved acoustic sheet and the reinforcing sheet of the piezoelectric audio device 211 and a piezoelectric audio device 212, which corresponds to the curved acoustic sheet 21 and reinforcing sheet 22 shown in FIG. 2, the piezoelectric audio device 211 and the piezoelectric Audio Devices in the 212, the area of ​​the surface portion of the curved acoustic sheet and the reinforcing sheet are different.
[0125]
　It is noted that the configuration of the piezoelectric audio device 211 and the piezoelectric audio device 212, the shape of the curved acoustic sheets of those piezoelectric audio device is not limited to the example shown in FIG. 1, other, Ya configuration shown in FIGS. 3 and 4 shapes, such as may be any configuration and shape. It can also have different configurations in a piezoelectric audio device 211 and the piezoelectric audio device 212 may be or have different their shape of the curved acoustic sheet.

claims

Made from a sheet-like piezoelectric material, a first sheet having a curved shape,
　a first sheet and substantially the same shape, and a second sheet arranged in superposed on the first sheet
　comprises electro-acoustic transducer.
[Requested item 2]
　It said second sheet is a nonwoven
　electro-acoustic transducer according to claim 1.
[Requested item 3]
　A first sheet and substantially the same shape, wherein the second sheet from the first sheet side arranged superimposed on the opposite side, further comprising a third sheet made of a sheet-like piezoelectric material
　electro-acoustic transducer according to claim 2.
[Requested item 4]
　The second sheet is made of a piezoelectric material
　electro-acoustic transducer according to claim 1.
[Requested item 5]
　It said second sheet is bonded to said first sheet
　electro-acoustic transducer according to claim 1.
[Requested item 6]
　Said first sheet and said second sheet, the pressing portion provided at an end portion of said first sheet and said second sheet, it is pressed is sandwiched between the frame fixing member and the frame base It is secured by
　electro-acoustic transducer according to claim 1.
[Requested item 7]
　The frame is fixed member and the frame base, opening exposing said first sheet and said second sheet is provided
　electro-acoustic transducer according to claim 6.
[Requested item 8]
　Wherein one frame fixing member and at least one of said frame base, when said frame fixing member and the frame base is viewed from a first direction substantially perpendicular to the second direction arranged, the first direction tapered portion so that the width of the opening is changed is formed for
　electro-acoustic transducer according to claim 7.
[Requested item 9]
　The tapered portion is formed such that the first width of the first sheet and the farther position from the second sheet opening in direction becomes wider
　electroacoustic transducer according to claim 8.
[Requested item 10]
　The tapered portion, the first width of the first sheet and the farther position from the second sheet opening in direction is formed to be narrower
　electroacoustic transducer according to claim 8.
[Requested item 11]
　It has a curved shape, a first sheet consisting of a sheet-like piezoelectric material, and a said first sheet and substantially the same shape, with a second sheet arranged in superposed on the first sheet a first electro-acoustic transducer,
　made from a sheet-like piezoelectric material having a curved shape, a second electrical with said first sheet or said third sheet area is different from the second sheet an acoustic transducer
　electroacoustic transducer comprising a.
[Requested item 12]
　Wherein the first electro-acoustic transducer and electro-acoustic transducer for the low frequency of said second electro-acoustic transducer, for adjusting the frequency characteristic to protect the electro-acoustic transducer for the low frequency protection adjustment unit is connected
　electro-acoustic converter according to claim 11.
[Requested item 13]
　The protective adjustment unit, the protection resistor or a low-pass filter
　electroacoustic transducer according to claim 12.
[Requested item 14]
　It has a curved shape, a first sheet consisting of a sheet-like piezoelectric material, and a said first sheet and substantially the same shape, with a second sheet arranged in superposed on the first sheet a first electro-acoustic transducer,
　has a curved shape, a third sheet made of a sheet-like piezoelectric material, and a third sheet and substantially the same shape, are superimposed on the third sheet has a fourth sheet disposed, said third sheet and the fourth sheet is the first sheet and the second sheet and the second electroacoustic transducer area different
　electrical comprise acoustic conversion device.