JP2000278795A - Piezoelectric receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric receiver whose sound pressure characteristic can considerably be enhanced at a low cost with a simple configuration. SOLUTION: A piezoelectric diaphragm 2 formed by adhering a piezoelectric element 2a with electrodes at both sides of a piezoelectric ceramic to a metallic disk 2b is held at an inner side of a package 1 via an elastic body 3 formed by folding a thin plate. Though the configuration above, since the motion of the diaphragm 2 shows behavior similar to a translational motion compared with the conventional technology, the receiver functions as an efficient sound source.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric receiver used as a receiver of an information terminal for voice communication such as a portable telephone.

[0002]

2. Description of the Related Art Piezoelectric receivers have a simple structure and can be manufactured at low cost, and the driving circuit has a simple structure as compared with a conductive type receiver. Therefore, the piezoelectric receiver is used as a receiver for a voice communication terminal such as a mobile phone. Widely used. FIGS. 17 and 18 show an example of a typical structure of a conventional piezoelectric receiver. FIG. 17 is an exploded perspective view of a conventional piezoelectric receiver, and FIG. 18 is a partial sectional view of the piezoelectric receiver of FIG. 17 and 18, reference numeral 20a denotes a piezoelectric element having electrodes formed on both sides of a piezoelectric ceramic, 20b denotes a metal plate, 20 denotes a piezoelectric vibration plate in which the piezoelectric element 20a is bonded to one surface of the metal plate 20b, and 21 and 22 denote piezoelectric vibrating plates. The case and the back plate constituting the housing of the piezoelectric receiver, 21a are the piezoelectric vibrating plate 20
, 23 is a small hole for resonance control provided on the back plate 22, 24 is a lead wire bonded to an electrode on the piezoelectric ceramic of the piezoelectric vibration plate 20 and a metal plate, and 25 is a case. 21 is provided on the bottom surface of the piezoelectric vibrating plate 20.
This is a sound emission hole that plays a role of emitting sound waves generated by the sound to the outside.

[0003] A face cloth as a resistance material is adhered to the small holes 23 for resonance control. As such a braking resistance, a plurality of thin tubes may be used instead of the small holes and the face cloth.

The outer periphery of the piezoelectric vibration plate 20 is bonded and fixed to a vibration plate holding portion 21a of a resin case 21 using silicon or the like. Thereafter, the back plate 22 is pressed into the case 21.

[0005] The above-described conventional piezoelectric receiver includes a lead wire 24.
When an AC voltage is applied to the piezoelectric vibrating plate 20 from the drive circuit through the piezoelectric vibrating plate 20, the piezoelectric vibrating plate 20 vibrates due to the expansion and contraction of the piezoelectric element 20 a bonded to the metal plate 20 b, causing the air in the case 21 to vibrate. To generate sound pressure. And
This sound pressure is emitted out of the case 21 through the sound emission hole 25 on the bottom surface of the case 21 as sound.

[0006] The sound pressure of the sound emitted from the piezoelectric receiver is
It is proportional to the amount of air (the volume excluded) that is eliminated by the vibration of the piezoelectric diaphragm 20.

[0007]

However, in the conventional piezoelectric receiver, as shown in FIG. 18, the entire outer periphery of the piezoelectric vibrating plate 20 is fixed to the vibrating plate holding portion 21a by surface contact. For this reason, the contact surface between the piezoelectric vibrating plate 20 and the vibrating plate holding portion 21a does not contribute to the generation of sound pressure. Therefore, as shown in FIG. The diameter D1 of the portion is greatly reduced, and as a result, the conversion efficiency of converting an electric signal into sound pressure is deteriorated, and a piezoelectric receiver having a high output sound pressure cannot be obtained.

Further, since the piezoelectric element 20a is bonded only to one surface of the metal plate 20b, a piezoelectric receiver having a high output sound pressure cannot be obtained due to insufficient driving force of the piezoelectric element. Therefore, in the prior art, an attempt has been made to obtain a piezoelectric receiver having a high output sound pressure by bonding piezoelectric elements to both sides of a metal plate to improve the driving force of the piezoelectric elements. However, with this configuration, there are problems such as an increase in the number of piezoelectric elements, an increase in the number of piezoelectric elements, an increase in the number of steps, and an increase in the number of steps and the number of steps, as compared to a case in which the piezoelectric elements are bonded only to one side of the metal plate. was there.

SUMMARY OF THE INVENTION The present invention has been made in order to improve such a conventional problem, and has as its object to provide a piezoelectric receiver having a greatly improved sound pressure with a simple configuration at a low cost.

[0010]

The present invention has the following configuration to achieve the above object.

That is, in the piezoelectric receiver according to the first configuration of the present invention, a piezoelectric vibrating plate formed by bonding a piezoelectric element having electrodes formed on both surfaces of a piezoelectric ceramic to a metal plate is held in a housing via an elastic member. It is characterized by having been done. According to such a configuration, the movement of the piezoelectric vibration plate exhibits a behavior closer to parallel movement as compared with the conventional piezoelectric receiver, so that it can function as a more efficient sound source than the conventional technology.

Further, in a piezoelectric receiver according to a second configuration of the present invention, a piezoelectric vibrating plate obtained by bonding a piezoelectric element having electrodes formed on both surfaces of a piezoelectric ceramic to a metal plate is provided around the metal plate. It is characterized in that it is held in the housing via an elastic body formed continuously with the plate. According to such a configuration, since the motion of the diaphragm exhibits a behavior closer to parallel movement as compared with the conventional piezoelectric receiver, the diaphragm can function as a more efficient sound source than the conventional technology. Further, since the elastic body is continuously formed on the metal plate, the number of components can be reduced.

Further, in the piezoelectric receiver according to the third configuration of the present invention, a piezoelectric vibration plate formed by bonding a piezoelectric element having electrodes formed on both surfaces of a piezoelectric ceramic to a metal plate is held in a housing, and the piezoelectric vibration A second vibrating plate is provided in the vicinity of a position where the maximum amplitude of the plate is generated, separated from the piezoelectric vibrating plate. According to such a configuration, the second diaphragm attached to the piezoelectric vibrating plate performs a parallel motion with an amplitude substantially equal to the maximum amplitude of the piezoelectric diaphragm, so that it can function as a more efficient sound source than the prior art.

According to a fourth aspect of the present invention, there is provided a piezoelectric receiver comprising: a piezoelectric element having electrodes formed on both sides of a piezoelectric ceramic; and at least one metal plate having an opening in a central portion. A piezoelectric vibrating plate formed by laminating and bonding the piezoelectric element to the metal plate so as to cover the opening is held in a housing. According to this configuration, the maximum amplitude of the piezoelectric diaphragm can be increased by increasing the bending moment generated in the piezoelectric element or by reducing the energy required for vibration. As a result, it can function as a sound source having a higher sound pressure than the conventional technology.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described more specifically with reference to embodiments.

<First Embodiment> Hereinafter, a first embodiment of the present invention will be described.
An embodiment will be described with reference to the drawings.

FIG. 1 is a partially cutaway perspective view of a piezoelectric receiver according to a first embodiment of the present invention. FIG. 2 is a sectional view of the piezoelectric receiver according to the first embodiment of the present invention.

1 and 2, reference numeral 1 denotes a resin case constituting a housing of a piezoelectric receiver, 2a denotes a disk-shaped piezoelectric element having electrodes formed on both surfaces of a piezoelectric ceramic, 2b denotes a disk-shaped metal plate, Reference numeral 2 denotes a piezoelectric element 2a on one surface of a metal plate 2b.
3 is an elastic body for supporting the piezoelectric vibrating plate 2 and attached to the case 1, and 4 is an attaching member for attaching the elastic body 3 to the case 1. 1 and 2, a lead wire connected to the electrode of the piezoelectric element 2a and the metal plate 2b, and a resin-made back plate that forms a housing together with the case 1 are omitted. Although a sound emission hole for emitting sound and a small hole for resonance control are not shown, they are provided on the case 1 or the back plate in a known manner.

FIG. 3 is a schematic structural view of the elastic body 3 used in the piezoelectric receiver of FIGS. 1 and 2, FIG. 3 (a) is a plan view, and FIG. 3 (b) is a side view. As shown in the figure, the elastic body 3 is formed by forming an elastic member such as a metal thin plate or a resin thin plate into a substantially V-shape. The central portion 31 is fixed to the case 1 by using the mounting member 4 and is connected to the central portion 31. Both ends 32 of arm 33
Is fixed to the outer peripheral portion of the metal plate 2b of the piezoelectric vibration plate 2 by bonding or the like.

FIG. 4 is a plan view showing another configuration of the elastic body. The elastic body 3 ′ of FIG. 4 differs from the elastic body 3 of FIG. 3 in that the piezoelectric vibrating plate 2 is supported at three locations in that it is supported at three locations. Arm part 33 formed radially from central part 31
Are bent at a predetermined angle in the same direction as in the elastic member of FIG. When the arm portion 33 is continuously formed radially from the central portion 31, the production of the elastic body is facilitated. Further, by bending the arm portion 33 at a predetermined angle, the piezoelectric vibrating plate 2 can be lifted from the case 1 and held, and a space necessary for the vibration of the piezoelectric vibrating plate 2 can be secured.

The elastic body 3 has a structure for holding the piezoelectric vibrating plate 2 at two places as shown in FIG. 3, a structure for holding the piezoelectric vibrating plate 2 at three places as shown in FIG. May hold the piezoelectric vibrating plate 2.

In FIG. 1, when an electric signal is applied between an electrode formed on the surface of the piezoelectric element 2a and the metal plate 2b,
The piezoelectric element 2a bonded to the metal plate 2b expands and contracts. Thereby, bending vibration is excited in the piezoelectric vibration plate 2 and the elastic body 3, and the vibration is transmitted to the air in the case 1 to generate a sound pressure.
This sound pressure is emitted as sound from the sound output hole.

FIG. 5 schematically shows the vibration behavior of the piezoelectric diaphragm according to the present embodiment. In the present embodiment, it is close to a state where the outer peripheral portion of the piezoelectric vibration plate 2 is supported by a finite number of elastic springs. By elastically supporting the piezoelectric vibration plate 2 with the elastic body 3 in this manner, the peripheral portion of the piezoelectric vibration plate 2 can be vibrated greatly. Vibration behavior of conventional piezoelectric diaphragm (Fig. 1
As is clear from comparison with 9), since the movement of the piezoelectric diaphragm 2 exhibits a behavior close to parallel movement, the area of the sound source is greatly increased as compared with the related art. As a result, it can function as an efficient sound source.

FIG. 6 is a sectional view showing another method of supporting the piezoelectric vibrating plate 2 by the elastic body 3. The support method of FIG.
1 and 2, the center of the elastic body 3 is fixed to the piezoelectric vibrating plate 2, and the end of the elastic body 3 is fixed to the case 1. Even with such a supporting method, the same effect as described above can be obtained because the piezoelectric vibration plate 2 is elastically supported by the elastic body 3.

By the way, in the piezoelectric receiver shown in FIGS. 1 and 2, in FIG.
When the piezoelectric vibrating plate 2 vibrates to the B side (the side where the elastic body 3 is present), the rigidity of the elastic body 3 when vibrating to the side where no elastic body is present is significantly greater than the rigidity of the elastic body 3 when vibrating to the B side (the side where the elastic body 3 is present). Therefore, as can be seen from the schematic diagram of the vibration behavior shown in FIG.
The amplitude to the side becomes smaller than the amplitude to the B side.

This problem can be solved by adopting a method of supporting the piezoelectric vibration plate 2 as shown in FIG. FIG.
In (A), two elastic members 3 are bonded to each other back to center, and one end of one elastic member 3 is fixed to the piezoelectric vibration plate 2 and the other end of the elastic member 3 is fixed to the case 1. I have.
In FIG. 7B, two elastic members 3 face each other and their ends are connected to each other. The central portion of one elastic member 3 is connected to the piezoelectric vibration plate 2 and the central portion of the other elastic member 3 is connected. The case 1
To each other.

By adopting the method of supporting the piezoelectric vibrating plate 2 as shown in FIG. 7, the piezoelectric vibrating plate 2 is improved so as to be held with the same force with respect to the vertical movement in the figure. FIG. 8 schematically shows the vibration behavior of the piezoelectric diaphragm supported as shown in FIG. As shown in FIG.
The vibration behavior on the side becomes almost symmetric, and the efficiency of the sound source can be further improved.

Further, by setting the resonance frequency of the elastic body 3 to a frequency of 1 kHz or less, particularly 500 Hz or less, at which sound pressure cannot be sufficiently secured by a normal piezoelectric receiver, low-frequency characteristics during reproduction can be improved. You can also.

<Second Embodiment> Hereinafter, a second embodiment of the present invention will be described.
An embodiment will be described with reference to the drawings.

FIG. 9 is an exploded perspective view of a piezoelectric receiver according to a second embodiment of the present invention, which is partially cut away.

In the figure, reference numeral 1 denotes a resin case constituting a housing of the piezoelectric receiver;
2a is a disk-shaped piezoelectric element having electrodes formed on both sides of a piezoelectric ceramic, 2b is a disk-shaped metal plate, 2 is a piezoelectric element having a piezoelectric element 2a bonded to one surface of a metal plate 2b. The diaphragms 3a, 3b, 3c are elastic bodies formed in the shape of an arm by cutting out the outer periphery of the piezoelectric diaphragm 2.
Note that, in FIG. 9, a lead wire connected to the electrode of the piezoelectric element 2a and the metal plate 2b, and a resin-made rear plate that forms a housing together with the case 1 are omitted. Although a sound emission hole for emitting sound and a small hole for resonance control are not shown, they are provided on the case 1 or the back plate in a known manner.

The distal ends of the elastic members 3a, 3b and 3c are fixed to the convex portions 1a, 1b and 1c with an adhesive or the like.
The protrusions 1a, 1b, and 1c are formed so as to protrude so that a sufficient vibration space of the piezoelectric vibration plate 2 is secured. The piezoelectric vibration plate 2 is thus fixed to the case 1 via the elastic bodies 3a, 3b, 3c.

When an electric signal is applied between the electrode formed on the surface of the piezoelectric element 2a and the metal plate 2b, the piezoelectric element 2a bonded to the metal plate 2b expands and contracts. Thereby, bending vibration is excited in the piezoelectric vibration plate 2, and the vibration is transmitted to the air in the case to generate a sound pressure. This sound pressure is emitted as sound from the sound output hole.

In this embodiment, the peripheral portion of the piezoelectric vibration plate 2 can be vibrated by elastically supporting the piezoelectric vibration plate 2 with the elastic members 3a, 3b, and 3c. Is shown. According to this configuration, as described in the first embodiment, the area of the sound source is significantly increased as compared with the related art. As a result, it can function as an efficient sound source.

Further, the elastic members 3a, 3b and 3c are formed continuously on the outer peripheral portion of the piezoelectric vibration plate 2 without using the elastic member for supporting the piezoelectric vibration plate 2 as a separate member. The effect of cost reduction is added.

Also, as shown in FIG.
By bending the b and 3c in the same direction, a vibration space can be secured without providing a convex portion formed on the case 1. It goes without saying that such an embodiment has the same effect as that of FIG.

Further, in the present embodiment, the elastic body is 3
a, 3b, and 3c have been described, but it goes without saying that the same effect can be obtained even when there are two or four or more elastic bodies.

Further, the elastic body is not limited to an arm formed by cutting out the outer periphery of the metal plate 2b and forming the arm substantially in the same direction as the outer peripheral edge as shown in FIGS. May be formed radially and continuously on the outer peripheral end of the device. However, as shown in FIGS. 9 and 10, if the arm is formed in the substantially same direction as the outer peripheral direction of the metal plate 2b, the device can be downsized while securing a necessary arm length.

Further, similarly to the first embodiment, by setting the resonance frequency of the elastic body to a frequency of 1 kHz or less, particularly 500 Hz or less, at which sound pressure cannot be sufficiently secured by a normal piezoelectric receiver, reproduction is performed. Needless to say, it is also possible to improve the low frequency characteristics of the above.

<Third Embodiment> Hereinafter, a third embodiment of the present invention will be described.
An embodiment will be described with reference to the drawings.

FIG. 11 is a partially cutaway perspective view of a piezoelectric receiver according to a third embodiment of the present invention. FIG. 12 is a sectional view of a piezoelectric receiver according to the third embodiment of the present invention.

11 and 12, reference numeral 1 denotes a resin case constituting a housing of a piezoelectric receiver, 2a denotes a disk-shaped piezoelectric element having electrodes formed on both sides of a piezoelectric ceramic, 2b denotes a disk-shaped metal plate, Reference numeral 2 denotes a piezoelectric vibration plate having a piezoelectric element 2a adhered to one surface of a metal plate 2b, reference numeral 5 denotes a second vibration plate made of a thin metal plate or a resin film, and reference numeral 6 denotes a second vibration plate 5 attached to the piezoelectric vibration plate 2. Mounting material. In FIGS. 11 and 12, a lead wire connected to the electrode of the piezoelectric element 2a and the metal plate 2b, and a resin-made rear plate that forms a housing together with the case 1 are omitted. Although a sound emission hole for emitting sound and a small hole for resonance control are not shown, they are provided on the case 1 or the back plate in a known manner.

The second diaphragm 5 is attached to a portion (the center of the piezoelectric diaphragm 2 in this example) of the piezoelectric diaphragm 2 where the largest amplitude is generated via an attachment 6 with an adhesive or the like. I have. The piezoelectric diaphragm 2 is bonded and fixed to the diaphragm holder 1d of the case 1 using silicon or the like.

When an electric signal is applied between the electrode formed on the surface of the piezoelectric element 2a and the metal plate 2b, the piezoelectric element 2a bonded to the metal plate 2b expands and contracts. As a result, bending vibration is excited in the piezoelectric vibration plate 2, and the second vibration plate 5 attached to a location where the maximum amplitude of the piezoelectric vibration plate 2 is generated vibrates greatly, transmitting vibration to the air in the case 1 and sound. Generate pressure. This sound pressure is emitted as sound from the sound output hole.

In the present embodiment, since the second diaphragm 5 is attached to a position where the maximum amplitude of the piezoelectric diaphragm 2 occurs, the second piezoelectric diaphragm 5 is parallelized at the maximum amplitude of the piezoelectric diaphragm 2. It can move and greatly increase the area of the sound source and the amount of air rejected by vibration compared to the prior art, and can function as an efficient sound source.

Further, in the present configuration, the second diaphragm 5 is made smaller than the diaphragm 2, and the lowest resonance frequency of the second diaphragm 5 is lower than the lowest resonance frequency of the diaphragm 2.
For example, by setting the frequency to about 500 Hz, the shortage of the sound pressure level of 1 kHz or less, which is a drawback of the frequency characteristics of a normal piezoelectric receiver, is improved by increasing the sound pressure level using the resonance of the second diaphragm 5. However, the effect of improving the bass reproduction ability can also be added.

In addition, by adding the configuration of the first or second embodiment to this embodiment, it goes without saying that the effect of the first or second embodiment can be added.

<Fourth Embodiment> Hereinafter, a fourth embodiment of the present invention will be described.
An embodiment will be described with reference to the drawings.

FIG. 13 is an exploded perspective view of a piezoelectric diaphragm of a piezoelectric receiver according to a fourth embodiment of the present invention.

In the same figure, reference numeral 2a denotes a disk-shaped piezoelectric element having electrodes formed on both surfaces of a piezoelectric ceramic, 2b denotes a disk-shaped metal plate, and 2c denotes a ring-shaped (doughnut-shaped) second metal having an open center. The plate 2 has a second surface on one side of the metal plate 2b.
This is a piezoelectric vibration plate to which a piezoelectric element 2a is adhered via a metal plate 2c.

When an electric signal is applied between the electrode formed on the surface of the piezoelectric element 2a and the metal plate 2b, the piezoelectric element 2a bonded to the metal plate 2b expands and contracts. Thereby, bending vibration is excited in the piezoelectric vibration plate 2, and the vibration is transmitted to the air in the case to generate a sound pressure. This sound pressure is emitted as sound from the sound output hole.

FIG. 14A is a sectional view of a conventional piezoelectric vibrating plate, and FIG. 14B is a partially enlarged sectional view of the conventional piezoelectric vibrating plate. In FIG. 14B, a dashed line 10 indicates a neutral plane, and an arrow in a region 11 indicated by a two-dot chain line indicates a moment distribution that plays a role of bending the diaphragm. The length of the arrow indicates the magnitude of the moment in a pseudo manner. FIG. 15A is a sectional view of the piezoelectric vibrating plate of the present embodiment, and FIG. 15B is a partially enlarged sectional view of the piezoelectric vibrating plate of the present embodiment. This figure also shows the moment distribution as in FIG.

Since both piezoelectric diaphragms use the same piezoelectric element 2a, the force generated in the piezoelectric element 2a under the same signal is the same. However, in the present embodiment shown in FIGS. 13 and 15, the distance from the neutral surface 10 to the force generated on the piezoelectric element 2a can be increased, so that the driving moment for vibrating the piezoelectric diaphragm is increased. I can do it. This makes it possible to increase the amplitude of the piezoelectric diaphragm, realize a piezoelectric diaphragm with an improved sound pressure level, and realize an efficient sound source.

FIG. 16 is a sectional view of a piezoelectric vibrating plate having another configuration of the present embodiment.

The piezoelectric vibrating plate shown in FIG. 16A is composed of a disk-shaped piezoelectric element 2a and a ring-shaped (doughnut-shaped) metal plate 2b having an open central portion. 2b is adhered to the inner peripheral portion. According to the piezoelectric vibrating plate having such a configuration, the bending rigidity is reduced and the mass of the vibrating portion is reduced because the metal plate 2b is not bonded to most of the portions where bending vibration occurs. Therefore, the vibration energy required to vibrate the piezoelectric vibration plate at a predetermined amplitude can be made much smaller than that of the conventional piezoelectric vibration plate shown in FIG. The amplitude of the piezoelectric diaphragm increases. As a result, a piezoelectric diaphragm having an improved sound thickness level is realized, and an efficient sound source can be realized.

The piezoelectric vibrating plate shown in FIG. 16B has a disk-shaped piezoelectric element 2a, a ring-shaped (doughnut-shaped) metal plate 2b having an open central portion, and a ring-shaped metal plate having an open central portion. It comprises a (doughnut-shaped) second metal plate 2c, and is formed by bonding the outer peripheral portion of the piezoelectric element 2a and the inner peripheral portion of the metal plate 2b via the second metal plate 2c. The piezoelectric diaphragm having such a configuration has the piezoelectric diaphragm of FIGS.
It has both the effect of increasing the driving moment for vibrating the piezoelectric diaphragm and the effect of reducing the energy required to vibrate the piezoelectric diaphragm, which the piezoelectric diaphragm of FIG. 16A has. Therefore, by the synergistic effect, the amplitude of the piezoelectric diaphragm is further increased, and a piezoelectric diaphragm with an improved sound pressure level can be realized, and an efficient sound source can be realized.

The above-described piezoelectric vibrating plate of the present embodiment is held in a housing to complete a piezoelectric receiver. At this time, by adding the first, second, or third embodiment to this embodiment, it is possible to add the effect of the first, second, or third embodiment. Needless to say.

[0058]

As described above, according to the present invention, a piezoelectric receiver having a simple structure and greatly improved sound pressure can be obtained at low cost.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view of a piezoelectric receiver according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the piezoelectric receiver according to the first embodiment of the present invention.

FIGS. 3A and 3B are schematic diagrams illustrating a configuration of an elastic body of the piezoelectric receiver according to the first embodiment of the present invention. FIG. 3A is a plan view, and FIG. 3B is a side view.

FIG. 4 is a plan view showing another configuration of the elastic body of the piezoelectric receiver according to the first embodiment of the present invention.

FIG. 5 is an explanatory diagram illustrating a vibration behavior of a piezoelectric diaphragm of the piezoelectric receiver according to the first embodiment of the present invention.

FIG. 6 is a cross-sectional view illustrating another configuration of the piezoelectric receiver according to the first embodiment of the present invention.

FIG. 7 is a sectional view showing still another configuration of the piezoelectric receiver according to the first embodiment of the present invention.

FIG. 8 is an explanatory diagram showing a vibration behavior of a piezoelectric diaphragm of the piezoelectric receiver of FIG. 7 of the present invention.

FIG. 9 is a partially cutaway exploded perspective view of a piezoelectric receiver according to a second embodiment of the present invention.

FIG. 10 is an exploded perspective view of another configuration of the piezoelectric receiver according to the second embodiment of the present invention, which is partially cut away.

FIG. 11 is a partially cutaway perspective view of a piezoelectric receiver according to a third embodiment of the present invention.

FIG. 12 is a sectional view of a piezoelectric receiver according to a third embodiment of the present invention.

FIG. 13 is an exploded perspective view of a piezoelectric diaphragm of a piezoelectric receiver according to a fourth embodiment of the present invention.

FIG. 14A is a cross-sectional view of a piezoelectric diaphragm of a typical piezoelectric receiver according to the related art, and FIG.
Is a partially enlarged sectional view thereof.

FIG. 15A is a sectional view of a piezoelectric vibrating plate of a piezoelectric receiver according to a fourth embodiment of the present invention.
FIG. 5 (b) is a partially enlarged sectional view thereof.

FIG. 16 is a cross-sectional view of a piezoelectric diaphragm of a piezoelectric receiver having another configuration according to the fourth embodiment of the present invention.

FIG. 17 is an exploded perspective view of a typical piezoelectric receiver in the related art.

FIG. 18 is a partial cross-sectional view of a typical piezoelectric receiver in the prior art.

FIG. 19 is an explanatory view showing a vibration behavior of a piezoelectric diaphragm of a typical piezoelectric receiver in the related art.

[Explanation of symbols]

 1, 21 Case 1a, 1b, 1c Convex portion 2a, 20a Piezoelectric element 2b, 20b Metal plate 2c Second metal plate 2, 20 Piezoelectric vibration plate 3, 3'3a, 3b, 3c Elastic body 4, 6 Mounting material 5 2nd diaphragm 21a, 1d diaphragm holding part 22 back plate 23 small hole for resonance control 24 lead wire 25 sound emission hole 31 central part 32 end part 33 arm part

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kawasa Osamu Osamu 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F-term (reference) 5D004 AA01 AA02 AA09 BB01 CD02 CD07 CD08 DD02 FF09

Claims (11)

[Claims] 1. A piezoelectric receiver characterized in that a piezoelectric vibrating plate formed by bonding a piezoelectric element having electrodes formed on both surfaces of a piezoelectric ceramic to a metal plate is held in a housing via an elastic member. 2. The piezoelectric receiver according to claim 1, wherein the elastic member has two or more thin plate-like arms formed radially from a central portion, and the arms are bent in the same direction. . 3. The piezoelectric receiver according to claim 2, wherein one of the center portion and the tip portion of the arm portion is fixed to the piezoelectric diaphragm, and the other is fixed to the housing. 4. The piezoelectric receiver according to claim 1, wherein the piezoelectric vibrating plate is held by a plurality of connected elastic members. 5. A piezoelectric vibrating plate formed by bonding a piezoelectric element having electrodes formed on both surfaces of a piezoelectric ceramic to a metal plate via an elastic body formed around the metal plate and continuously with the metal plate. A piezoelectric receiver, which is held in a housing. 6. The piezoelectric receiver according to claim 5, wherein the elastic body is an arm-shaped elastic body formed in a substantially same direction as an edge of the metal plate by notching the metal plate. 7. The piezoelectric receiver according to claim 5, wherein the elastic body is inclined on the same side of the metal plate. 8. A piezoelectric vibrating plate formed by bonding a piezoelectric element having electrodes formed on both surfaces of a piezoelectric ceramic to a metal plate is held in a housing, and the piezoelectric vibrating plate is provided in the vicinity of a position where the maximum amplitude of the piezoelectric vibrating plate is generated. A piezoelectric vibrator, wherein a second diaphragm is provided at a distance from the piezoelectric vibrator. 9. The minimum resonance frequency of the second diaphragm is:
9. The piezoelectric receiver according to claim 8, wherein the frequency is lower than a lowest resonance frequency of the piezoelectric diaphragm. 10. A piezoelectric element having electrodes formed on both sides of a piezoelectric ceramic, and at least one metal plate having an opening in a central portion, wherein the piezoelectric element is formed of the metal so as to cover the opening of the metal plate. A piezoelectric receiver, wherein a piezoelectric vibration plate laminated and bonded to a plate is held in a housing. 11. The piezoelectric receiver according to claim 10, wherein the piezoelectric element is held on another metal plate via the metal plate having the opening.