JP2007194789A - Piezoelectric speaker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piezoelectric speaker whose sound pressure characteristics are improved by providing two piezoelectric resin complexes and increasing piezoelectric effect. <P>SOLUTION: The piezoelectric speaker is constituted by providing the two piezoelectric resin complexes 15A and 15B each composed of a plurality of piezoelectric element chips 11, a piezoelectric resin portion 13 made of organic resin charged on flank sides of the piezoelectric chips except electrode surfaces, and a peripheral resin portion 14 made of only organic resin at peripheries of the piezoelectric resin portion, providing an intermediate electrode film 15C as an intermediate layer between electrode surfaces of the two piezoelectric resin complexes, also providing conductive electrode films on both surfaces of the two piezoelectric complexes coming into contact with the intermediate electrode film, and coupling peripheral resin portions to a speaker frame body partially or entirely. Consequently, the sound pressure characteristics are improved. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a piezoelectric speaker using a piezoelectric element chip, and more particularly to a piezoelectric speaker capable of improving sound pressure characteristics.

  In general, a speaker causes a voice cone to mechanically vibrate due to the interaction between the current of this coil and the magnetic field of a permanent magnet by flowing an audio electric signal through a voice coil connected to the voice cone that plays the role of a diaphragm. The sound is reproduced by vibrating the air. In the reproduction of audio, it is ideal that the reproduction is performed efficiently over a wide range from a human audible frequency of several tens of Hz to several tens of kHz so as not to cause distortion. However, since it is difficult to cover a wide frequency range with one speaker, generally, a plurality of speakers corresponding to each region are used.

By the way, in recent years, there has been a great demand for reduction in size, weight, and thickness of audio devices such as stereo devices, televisions, and surround sound. In response to such demands, extremely thin and lightweight piezoelectric speakers have been developed.
This piezoelectric speaker is disclosed in, for example, Patent Documents 1, 2, 3, etc., and is composed of an epoxy resin and a large number of, for example, lead zirconate titanate (PZT) piezoelectric element chips, conductive electrode films, By using the piezoelectric element chip and the organic resin, the piezoelectric effect of the piezoelectric element and the elasticity of the organic resin are used.

JP 7-327298 A JP 2000-324598 A JP 2003-348692 A

However, in the conventional piezoelectric speaker described above, for example, the sound pressure characteristic at 1 kHz to 10 kHz is not good.
The present invention has been created in order to effectively solve the above-described problems.
An object of the present invention is to provide two piezoelectric resin composites composed of a plurality of piezoelectric element chips and an organic resin around the piezoelectric element chips, and include an intermediate electrode film as an intermediate layer between the electrode surfaces of the piezoelectric resin composites. An object of the present invention is to provide a piezoelectric speaker with improved sound pressure characteristics at 1 kHz to 10 kHz by enhancing the piezoelectric effect.

The present invention includes a plurality of piezoelectric element chips, a piezoelectric resin portion made of an organic resin filled on a side surface excluding the electrode surface of the piezoelectric element chip, and a peripheral resin portion made of only an organic resin around the piezoelectric resin portion. Two piezoelectric resin composites to be formed are provided, an intermediate electrode film is provided as an intermediate layer between the electrode surfaces of the two piezoelectric resin composites, and the two piezoelectric resin composites in contact with the intermediate electrode film The piezoelectric speaker is characterized in that a conductive electrode film is provided on both sides of the substrate, and a part or all of the peripheral resin portion is coupled to the speaker frame.

In the conventional known example, there is one piezoelectric resin composite composed of a plurality of piezoelectric element chips and an organic resin, and the shape of the piezoelectric resin composite is convex or concave in the vibration direction of the piezoelectric resin composite. A film is not formed. On the other hand, in the present invention, the shape of the two piezoelectric resin composites and the intermediate electrode film may be convex, concave or planar in the vibration direction of the piezoelectric resin composite.
When convex or concave in the vibration direction, the piezoelectric resin composite of the present invention is a part of a plane, a part of a cylindrical curved surface, a part of a conical curved surface, a part of a spherical curved surface, and a part of an ellipsoidal curved surface. It is also possible to have a form selected from one or more of them.

As the piezoelectric element chip, in addition to lead zirconate titanate (PZT) PZT, other composite material ceramics may be used. Specifically, lead zinc niobate titanate (PZNT) or magnesium magnesium niobate titanate (PMNT) whose piezoelectric strain constant is about three times larger than PZT can be used.
Importantly, in order to ensure a good piezoelectric effect, the pair of electrode surfaces in each piezoelectric element chip must be substantially parallel. Further, in all piezoelectric element chips used for the piezoelectric speaker, the distance between the electrode surfaces needs to be the same. The piezoelectric element chip in the present invention may have any shape except that the electrode surfaces are parallel and the distance between the electrode surfaces is the same. For example, the shape of the piezoelectric element chip may be a cylindrical body, a rectangular parallelepiped, a triangular prism, or the like. Moreover, the shape selected from 1 or more types among a cylinder, a rectangular parallelepiped, and a triangular prism may be sufficient, for example, a rectangular parallelepiped and a triangular prism can be mixed and used. Industrially, piezoelectric element chips having the same rectangular parallelepiped shape are recommended.

As the organic resin, an epoxy resin, a polyurethane resin, or the like can be used. The speaker frame may be made of a material that can fix and support the piezoelectric resin composite, and is required to have superior strength characteristics as compared with the piezoelectric resin composite, and the conductive characteristics are not particularly limited. In the speaker frame, what is important is the coupling state between the speaker frame and the piezoelectric resin composite. When the piezoelectric resin composite and the speaker frame are formed with a coupling portion and a non-coupling portion, the flexibility of the piezoelectric resin composite is increased and the sound pressure characteristics are improved. As the conductive electrode film, a vapor-deposited film on a piezoelectric element chip of a conductive substance such as carbon, aluminum, gold, silver, or copper having excellent conductivity characteristics, an organic resin film containing the conductive substance, or the vapor-deposited film And a composite of the organic resin film is preferable.

As the intermediate electrode film, a conductive material such as carbon, aluminum, gold, silver, and copper having excellent conductivity characteristics, an organic resin film containing the conductive material, or a vapor deposition film of the conductive material on a piezoelectric element chip And a composite of the organic resin film is preferable.
The role of the intermediate electrode film is to apply the same potential to the piezoelectric element chips existing in the two piezoelectric resin composites in contact with the intermediate electrode film. In the case of a piezoelectric element chip polarized in the same direction and perpendicular to the electrode surface, by applying the same potential, one piezoelectric element chip in contact with the intermediate electrode film expands in a direction perpendicular to the polarization direction, and at the same time The other piezoelectric element chip in contact with the intermediate electrode film contracts in a direction perpendicular to the polarization direction. In this case, the shape of the two piezoelectric resin composites and the intermediate electrode film may be convex, concave or planar in the vibration direction of the piezoelectric resin composite.

When one piezoelectric element chip in contact with the intermediate electrode film and the other piezoelectric element chip are polarized in a direction perpendicular to and opposite to the electrode surface, one piezoelectric element chip in contact with the intermediate electrode film is applied by applying the same potential. The other piezoelectric element chip expands and contracts in the same direction perpendicular to the polarization direction. Therefore, in the case of a piezoelectric element chip polarized in the opposite direction with the intermediate electrode film as a boundary, it is not applicable that the two piezoelectric resin composites and the intermediate electrode film have a planar shape. It is necessary that the resin composite is convex or concave in the vibration direction.
In addition, it is necessary to connect a lead wire for energizing an audio electric signal to the intermediate electrode film, and the connection of the lead wire may be provided through the peripheral resin portion. In addition, in order to protect the conductive electrode film provided on the upper part of the piezoelectric resin part and improve the speaker output characteristics, an organic resin film such as polyurethane resin, polyethylene resin, epoxy resin, etc. on one or both surfaces of the conductive electrode film. May be provided.

  According to the piezoelectric speaker of the present invention, two piezoelectric resin composites each including a plurality of piezoelectric element chips and an organic resin around the piezoelectric element chips are provided, and an intermediate electrode film is provided as an intermediate layer between the electrode surfaces of the piezoelectric resin composite. By improving the piezoelectric effect, the sound pressure characteristics at 1 kHz to 10 kHz can be improved. Moreover, it is easy to manufacture that the two piezoelectric resin composites and the intermediate electrode film may be convex, concave, or planar in the vibration direction as in the present invention, and the range of use is expanded. It can be said that the effect by this invention is large.

  Hereinafter, embodiments of the piezoelectric speaker according to the present invention will be described in detail.

FIG. 1 is an enlarged cross-sectional view of a main part showing a piezoelectric speaker of the present invention. FIG. 2 is a cross-sectional view of the piezoelectric speaker shown in FIG.
As shown in the figure, the piezoelectric speaker is filled with an organic resin 12 between a plurality of piezoelectric element chips 11 having the same rectangular parallelepiped shape, and the piezoelectric resin part 13 and the surroundings of the piezoelectric resin part 13 are joined together. The two piezoelectric resin composites 15A and 15B formed by the peripheral resin portion 14 made of only organic resin, and an intermediate electrode film provided as an intermediate layer between the electrode surfaces of the two piezoelectric resin composites 15A and 15B 15C, conductive electrode films 17A and 17B provided on both surfaces of the two piezoelectric resin composites 15A and 15B in contact with the intermediate electrode film 15C, and a frame body 16 coupled to the surrounding resin portion 14. .
The conductive electrode films 17A and 17B are connected by lead wires 18A, the intermediate electrode film 15C is connected by lead wires 18B through the peripheral resin portion 14, and an audio electric signal is transmitted from the audio signal source 18 to the lead wires 18A and 18B. Sound can be obtained by energizing.
As shown in FIGS. 1 and 2, in this embodiment, a plurality of piezoelectric element chips 11 and two piezoelectric resin composites 15A and 15B made of an organic resin around the piezoelectric element chip 11 are provided, and the piezoelectric resin composite is provided. By providing the intermediate electrode film 15C as an intermediate layer between the electrode surfaces of 15A and 15B and enhancing the piezoelectric effect, the sound pressure characteristics at 1 kHz to 10 kHz can be improved.

Further, details of the embodiment will be specifically described.
Piezoelectric resin composites 15A and 15B of a piezoelectric speaker were produced by the method disclosed in Japanese Patent Laid-Open No. 2003-348692. The used piezoelectric element chip 11 is a lead zirconate titanate (PZT) type piezoelectric element, and has dimensions of a rectangular parallelepiped having a length of 2 mm, a width of 2 mm, and a thickness of 0.2 mm. In addition, an epoxy resin is used as the organic resin 12 that is filled to bond the plurality of piezoelectric element chips 11 together. Since a 2 mm vertical and 2 mm horizontal plane is used as the electrode surface of the piezoelectric element chip 11, the thickness of the piezoelectric resin composites 15 </ b> A and 15 </ b> B is approximately the same as that of the piezoelectric element chip 11.
The produced piezoelectric resin composites 15A and 15B have the same shape, and a front view thereof is shown in FIG. 3, and a side view (illustration of the piezoelectric element chip is omitted) is shown in FIG. In FIG. 3, the opening angle, the radius of curvature, and the width dimension of the piezoelectric resin composite 15A are θ, R, and D, respectively. In FIG. 4, the length dimension of the piezoelectric resin composite 15A is L.

The piezoelectric element chips 11 are arranged in a lattice shape along a curved surface with an average interval of 0.4 mm between the piezoelectric element chips. That is, along the R curved surface of FIG. 3, the distance between the position of the long side of the piezoelectric element chip 11 and the arc-shaped end portions of the piezoelectric resin composites 15A and 15B in the angle θ direction is approximately the same. Fourteen piezoelectric element chips 11 are arranged at regular intervals of an average of 0.4 mm.
The arrangement of 14 pieces in the θ direction described above is repeated along the R curved surface by parallelly moving in the L direction in FIG. 4 at an equal interval of 2.4 mm on average, and a total of 196 pieces are respectively provided in the piezoelectric resin composites 15A and 15B. A piezoelectric element chip 11 is arranged. The dimensions of the obtained piezoelectric resin composites 15A and 15B are substantially the same, and the width D = 37.0 mm, the length L = 37.5 mm, and the average radius of curvature R = 45 mm. The dimensions of the piezoelectric resin portion 13 excluding the surrounding resin portion 14 from the piezoelectric resin composites 15A and 15B were substantially the same, the width was 33.1 mm, the length was 33.6 mm, and the average curvature radius was 45 mm. FIG. 5 shows an enlarged plan view of a main part of a part of the piezoelectric resin composite 15A according to the first embodiment. As shown in FIG. 5, 196 piezoelectric element chips 11 are arranged in a lattice pattern at equal intervals of 0.4 mm on average, 14 pieces in the X direction (see FIG. 5) and 14 pieces in the Y direction (see FIG. 5). The

Next, an intermediate electrode film 15C having an average thickness of 0.1 mm is provided between the piezoelectric resin composite 15A and the piezoelectric resin composite 15B, and the piezoelectric resin composite 15A, the intermediate electrode film 15C, and the piezoelectric resin composite 15B are configured. A piezoelectric resin composite 15 was produced. As the intermediate electrode film 15C, an epoxy resin containing silver which is a conductive metal was used. The dimensions of the obtained piezoelectric resin composite 15 were a width of 37 mm, a length of 38 mm, and an average curvature radius of 45 mm.
The frame body 16 to be coupled to the piezoelectric resin composite 15 is prepared with an acrylic resin having a thickness of 5 mm. The outer dimension of the frame 16 is a rectangular parallelepiped having a length of 60 mm, a width of 60 mm, and a thickness of 5 mm. The piezoelectric resin composite 15 (width 37 mm, length 38 mm) is put into the gap (length 37.2 mm, width 38.2 mm) of the frame 16, and two linear ends (length) of the piezoelectric resin composite 15. 38 mm portion) was aligned with the two upper side portions (length 38.2 mm portion) of the gap of the frame body, and the associated portion was bonded with epoxy resins 19A, 19a, 19B and 19b.
FIG. 6 shows a perspective view (a piezoelectric element chip is not shown) of a part of the coupling state of the piezoelectric resin composite 15 and the frame 16. As shown in FIG. 6, in this embodiment, the linear end of the piezoelectric resin composite 15 and the frame 16 are joined by the epoxy resin 19 </ b> A, but the two arc-shaped ends of the piezoelectric resin composite 15 It is not coupled to the frame body 16. That is, in the connection between the piezoelectric resin composite 15 and the frame body 16, a connection portion and a non-connection portion are formed.

The piezoelectric resin composite 15 combined with the frame 16 was cured at 60 ° C. for 1 hour. After the curing process, the piezoelectric resin composite 15 combined with the frame body 16 is washed, and the conductive aluminum electrode film 17A and the conductive aluminum electrode film 17A formed by vacuum deposition are formed on both surfaces of the piezoelectric resin portion 13 where the electrode surface of the piezoelectric element chip 11 exists. 17B was provided. The thicknesses of the aluminum electrode films 17A and 17B were almost the same and averaged 0.4 μm.
The conductive aluminum electrode films 17A and 17B are connected by lead wires 18A, the intermediate electrode film 15C is connected by lead wires 18B through the peripheral resin portion 14, and an audio electric signal is transmitted from the audio signal source 18 to the lead wires 18A and 18A. 18B was energized, and the sound pressure characteristic with respect to the frequency of the piezoelectric speaker was evaluated. The evaluation results of the sound pressure characteristics are shown in Table 1.
As shown in Table 1, it can be seen that the sound pressure characteristic of Example 1 shows 40 to 68 relative sound pressure dB in the frequency range of 1 kHz to 10 kHz.

As a comparative example, a piezoelectric resin composite 25 having no intermediate electrode film was produced by the method disclosed in Japanese Patent Application Laid-Open No. 2003-348692.
This comparative example is also a piezoelectric speaker previously filed and disclosed in Japanese Patent Application No. 2005-371403 by the present inventors.
The piezoelectric resin composite 25 is substantially the same as the piezoelectric resin composite 15A produced in Example 1. The used piezoelectric element chip 21 is the same as that of the first embodiment, and the organic resin 22 for bonding the piezoelectric element chip is also the same as that of the first embodiment. A total of 196 piezoelectric element chips 21 are arranged in a lattice pattern at regular intervals of an average of 0.4 mm, 14 pieces in the X direction (see FIG. 5), 14 pieces in the Y direction (see FIG. 5).
The dimensions of the obtained piezoelectric resin composite 25 are a width D = 37.0 mm, a length L = 37.5 mm, and an average curvature radius R = 45 mm. The dimensions of the piezoelectric resin portion 23 excluding the peripheral resin portion 24 from the piezoelectric resin composite 25 were a width of 33.0 mm, a length of 33.5 mm, and an average curvature radius of 45 mm.

Next, a frame body 26 to be coupled with the piezoelectric resin composite 25 is prepared with an acrylic resin having a thickness of 5 mm. The outer dimension of the frame 26 is a rectangular parallelepiped having a length of 60 mm, a width of 60 mm, and a thickness of 5 mm. Piezoelectric resin composite 25 (width 37.0 mm, length 37.5 mm) is placed in the gap (length 37.2 mm, width 37.7 mm) of frame 26, and two linear ends of piezoelectric resin composite 25 are arranged. The part (length 37.5 mm part) was matched with the two upper side parts (length 37.7 mm part) of the frame space part, and the meeting part was bonded with epoxy resins 29A, 29a, 29B and 29b.
FIG. 7 shows a perspective view (piezoelectric element chip is not shown) of a part of the coupled state of the piezoelectric resin composite 25 and the frame 26. As shown in FIG. 7, in this comparative example, the linear end of the piezoelectric resin composite 25 and the frame 26 are joined by the epoxy resin 29 </ b> A, but the two arc-shaped ends of the piezoelectric resin composite 25 are The frame 26 is not coupled. That is, in the connection between the piezoelectric resin composite 25 and the frame body 26, a connection portion and a non-connection portion are formed.

The piezoelectric resin composite 25 combined with the frame 26 was cured at 60 ° C. for 1 hour. After the curing treatment, the piezoelectric resin composite 25 combined with the frame body 26 is washed, and further, the conductive aluminum electrode film 27A and the conductive aluminum electrode film 27A formed by vacuum deposition are formed on both surfaces of the piezoelectric resin portion 23 where the electrode surface of the piezoelectric element chip 21 exists. 27B was provided. The thicknesses of the aluminum electrode films 27A and 27B were almost the same and averaged 0.4 μm.
After connecting the two lead wires 28A and 28B to the electrode films 27A and 27B, a sound electric signal is supplied to the lead wire from the sound signal source 18, and the sound pressure characteristics with respect to the frequency of the piezoelectric speaker are evaluated in the same manner as in the first embodiment. went. The evaluation results of the sound pressure characteristics are shown in Table 1.
As shown in Table 1, in the frequency range from 1 kHz to 10 kHz, the comparative example shows 35 to 61 relative sound pressure dB, and it can be seen that the sound pressure characteristic of the comparative example is inferior to that of Example 1.

The piezoelectric resin composite 35 of the piezoelectric speaker was produced by the method disclosed in Japanese Patent Laid-Open No. 2003-348692. The used piezoelectric element chip 31 is the same as that of the first embodiment, and the organic resin 32 for bonding the piezoelectric element chip 31 is the same as that of the first embodiment. In Example 2, unlike Example 1, piezoelectric resin composites 35A and 35B were produced in a planar shape having no curvature. The piezoelectric resin composites 35A and 35B have substantially the same shape, and FIG. 8 shows an enlarged plan view of a part of the piezoelectric resin composites 35A and 35B. As shown in FIG. 8, there are 14 piezo-electric element chips 31 in the X direction (see FIG. 8), 14 in the Y direction (see FIG. 8), and a total of 196 piezoelectric elements arranged at regular intervals of 0.4 mm on average. ing. As the electrode surface of the piezoelectric element chip 31 is a plane having a length of 2 mm and a width of 2 mm, the thickness of the piezoelectric resin composites 35A and 35B is approximately the same as that of the piezoelectric element chip 31. The dimensions of the obtained piezoelectric resin composites 35A and 35B are substantially the same and have a width of 38 mm and a length of 38 mm. The dimensions of the piezoelectric resin portion 33 excluding the surrounding resin portion 34 from the piezoelectric resin composites 35A and 35B were substantially the same, and the width was 34 mm and the length was 34 mm.

Next, an intermediate electrode film 35C having an average thickness of 0.1 mm is provided between the piezoelectric resin composite 35A and the piezoelectric resin composite 35B, and the piezoelectric resin composite 35A, the intermediate electrode film 35C, and the piezoelectric resin composite 35B are configured. A piezoelectric resin composite 35 was produced. As the intermediate electrode film 35C, as in Example 1, an epoxy resin containing silver which is a conductive metal was used. The obtained piezoelectric resin composite 35 had a width of 38 mm and a length of 38 mm.
A frame body 36 to be coupled to the piezoelectric resin composite 35 is prepared with an acrylic resin having a thickness of 5 mm. The outer dimension of the frame 36 is a rectangular parallelepiped having a length of 60 mm, a width of 60 mm, and a thickness of 5 mm. A piezoelectric resin composite 35 (width 38 mm, length 38 mm) is placed in the gap (length 38.2 mm, width 38.2 mm) of the frame 36, and four linear ends (length) of the piezoelectric resin composite 35 are placed. 38 mm portion) was aligned with the four upper side portions (length 38.2 mm portion) of the gap of the frame body, and the associated portions were bonded with epoxy resins 39A and 39B.
FIG. 9 shows a perspective view (piezoelectric element chip is not shown) of the coupling state of the piezoelectric resin composite 35 and the frame 36. As shown in FIG. 9, in Example 2, all of the four linear ends of the piezoelectric resin composite 35 are coupled by the frame body 36 and the epoxy resins 39A and 39B, and no uncoupled portion is formed. A cross-sectional view of the piezoelectric resin composite 35 bonded to the frame 36 is shown in FIG. As shown in FIG. 10, in Example 2, it can be seen that the piezoelectric resin composite 35 composed of the piezoelectric resin composite 35A, the intermediate electrode film 35C, and the piezoelectric resin composite 35B has a planar shape having no curvature.

The piezoelectric resin composite 35 bonded to the frame 36 was subjected to a curing process at 60 ° C. for 1 hour. After the curing process, the piezoelectric resin composite 35 bonded to the frame body 36 is washed, and further, the conductive aluminum electrode film 37A and the conductive aluminum electrode film 37A formed by vacuum deposition are formed on both surfaces of the piezoelectric resin portion 33 where the electrode surface of the piezoelectric element chip 31 exists. 37B was provided. The thicknesses of the aluminum electrode films 37A and 37B were substantially the same and averaged 0.4 μm.
The conductive aluminum electrode films 37A and 37B are connected by lead wires 38A, the intermediate electrode film 35C is connected by lead wires 38B through the peripheral resin portion 34, and an audio electric signal is transmitted from the audio signal source 18 to the lead wires 38A and 38A. 38B was energized, and the sound pressure characteristics with respect to the frequency of the piezoelectric speaker were evaluated in the same manner as in Example 1. The evaluation results of the sound pressure characteristics are shown in Table 1.
As shown in Table 1, in the frequency range from 1 kHz to 10 kHz, Example 2 shows 38 to 65 relative sound pressure dB, and it can be seen that the sound pressure characteristic of Example 2 is superior to that of the comparative example.

Table 2 shows the shape, approximate dimensions, coupling state with the frame, number of piezoelectric element chips, and sound pressure characteristics of the piezoelectric resin composites in Example 1, Comparative Example, and Example 2. From Table 2, it can be seen that the sound pressure characteristics of Examples 1 and 2 according to the present invention are superior to those of the comparative example.
That is, two piezoelectric resin composites composed of a plurality of piezoelectric element chips and an organic resin around the piezoelectric element chips are provided, and an intermediate electrode film is provided as an intermediate layer between the electrode surfaces of the two piezoelectric resin composites. It is considered that the sound pressure characteristics at 1 kHz to 10 kHz are improved by providing and enhancing the piezoelectric effect.
In addition, when the coupling portion and the non-coupling portion are formed in the coupling between the piezoelectric resin composite and the frame, it is considered that the flexibility of the piezoelectric resin composite is increased and the sound pressure characteristics are further improved.

なお、圧電樹脂複合体の形状として実施例１では円柱体曲面の一部の例を示し、実施例２では平面の一部の例を示したが、他の円錐体曲面の一部、楕円体曲面の一部などの近似曲面も適用可能である。
すなはち、圧電樹脂複合体の形状として、平面の一部、円柱体曲面の一部、円錐体曲面の一部、球体曲面の一部及び楕円体曲面の一部の内の１種以上から選ばれた形態においても、本発明の効果は失われない。

As the shape of the piezoelectric resin composite, Example 1 shows an example of a part of a cylindrical curved surface, and Example 2 shows an example of a part of a flat surface. An approximate curved surface such as a part of a curved surface is also applicable.
In other words, the shape of the piezoelectric resin composite may be one or more of a part of a plane, a part of a cylindrical curved surface, a part of a conical curved surface, a part of a spherical curved surface, and a part of an ellipsoidal curved surface. Even in the selected form, the effects of the present invention are not lost.

It is a principal part expanded sectional view which shows the piezoelectric speaker of this invention. It is AA arrow sectional drawing of the piezoelectric speaker shown in FIG. 1 is a front view of a piezoelectric resin composite 15A in Example 1. FIG. 3 is a side view of a piezoelectric resin composite 15A in Example 1. FIG. 3 is an enlarged plan view of a main part showing a part of a piezoelectric resin composite 15A in Example 1. FIG. FIG. 3 is a perspective view showing a coupling state between the piezoelectric resin composite 15 and the frame body in Example 1. It is a perspective view which shows the combined state of the piezoelectric resin composite body and frame in a comparative example. 6 is an enlarged plan view of a main part showing a part of a piezoelectric resin composite 35A in Example 2. FIG. It is a perspective view which shows the combined state of the piezoelectric resin composite body 35 in Example 2, and a frame. 6 is a cross-sectional view of a piezoelectric resin composite 35 coupled to a frame body in Example 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Piezoelectric element chip | tip, 12 ... Organic resin, 13 ... Piezoelectric resin part, 14 ... Ambient resin part,
15 ... piezoelectric resin composite, 15A ... piezoelectric resin composite, 15B ... piezoelectric resin composite,
15C ... Intermediate electrode film, 16 ... Frame, 17A ... Conductive electrode film, 17B ... Conductive electrode film,
18A ... Lead wire, 18B ... Lead wire, 19A ... Epoxy resin, 19a ... Epoxy resin,
19B ... epoxy resin, 19b ... epoxy resin,

Claims (1)

Piezoelectric resin portion formed of a plurality of piezoelectric element chips, an organic resin filled on the side surface excluding the electrode surface of the piezoelectric element chip, and a piezoelectric resin formed around the piezoelectric resin portion and a peripheral resin portion made of only organic resin Two resin composites are provided, an intermediate electrode film is provided as an intermediate layer between the electrode surfaces of the two piezoelectric resin composites, and conductive is provided on both surfaces of the two piezoelectric resin composites in contact with the intermediate electrode films. A piezoelectric speaker, characterized in that a conductive electrode film is provided and a part or all of the surrounding resin portion is coupled to a speaker frame.

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