JPH0638400U - Piezoelectric handset - Google Patents

Abstract

(57) [Summary] [Purpose] Prevents braking failure due to adhesive penetration. [Structure] In a case 1, a hole 12 is provided in a wall portion 13 forming an internal space 11, and the wall portion 13 has a recess 1 around the hole 12.
Have four. The piezoelectric vibrating plate 2 has a hole 1 in the inner space 11.
It is peripherally supported on the case 1 so that a cavity 111 containing 2 is formed. The acoustic resistance sheet 4 is adhered to the wall portion 13 with the adhesive 5 filled in the concave portion 14 to close the hole 12.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a piezoelectric handset, and more particularly to improvement of a piezoelectric handset used for telephones, intercoms and the like.

[0002]

[Prior art]

 In this type of piezoelectric receiver, the resonant frequency of the piezoelectric diaphragm and the resonant frequency of the cavity are considerably separated from each other, and the frequency characteristic between both resonant frequencies is deteriorated. A technique using a braking cloth is known as a means for solving such a problem. The damping cloth gives an appropriate acoustic resistance, flattens the frequency characteristics, and improves the frequency bandwidth. Such a technique is known, for example, from Japanese Utility Model Laid-Open No. 63-17899. The damping cloth is usually composed of a cloth of about several hundred meshes / inch, and this secures the acoustic resistance necessary for flattening the frequency characteristic. The braking cloth is bonded to the case that supports the piezoelectric diaphragm using an adhesive. The braking cloth is provided with a braking hole in advance, and the entire surface of the braking cloth is bonded to the case except the part corresponding to the braking hole. Such a technique is known, for example, in Japanese Utility Model Publication No. 63-17899.

[0003]

[Problems to be solved by the device]

 As described above, since the braking cloth is made of mesh cloth, when the braking cloth is bonded with the adhesive, the adhesive penetrates the entire bonding surface that is bonded around the braking hole. It was found that there was a problem that the acoustic characteristics of the braking cloth deteriorated and braking failure occurred. The above-mentioned prior art does not disclose means for solving the braking failure caused by the penetration of the adhesive.

Therefore, the present invention is to provide a piezoelectric handset capable of preventing braking failure due to penetration of an adhesive.

[0005]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention provides a piezoelectric receiver including a case, a piezoelectric diaphragm, and an acoustic resistance sheet, wherein the case has a ring-shaped internal space and a hole. Is provided in a wall forming the internal space, the wall has a recess around the hole, and the piezoelectric vibrating plate is formed with a cavity including the hole in the internal space. As described above, the acoustic resistance sheet is peripherally supported on the case, and the acoustic resistance sheet is adhered to the wall portion by the adhesive filled in the concave portion to close the hole.

[0006]

[Action]

 The case has a ring-shaped internal space, and the piezoelectric diaphragm is peripherally supported on the case so that a cavity is formed in the internal space. A piezoelectric handset that can be converted into an electric signal and output by using is obtained.

The case has a hole, the hole is provided in a wall portion forming an internal space, and the piezoelectric vibration plate is peripherally supported on the case so that a cavity including the hole is formed in the internal space. However, since the acoustic resistance sheet is adhered to the wall portion with an adhesive to close the holes, the acoustic resistance sheet and the holes can provide appropriate acoustic resistance, flatten the frequency characteristics, and improve the frequency characteristics.

In the case, the wall forming the internal space has a recess around the hole, and the acoustic resistance sheet is adhered to the wall by the adhesive filled in the recess. It works as an agent reservoir and can absorb fluctuations in the filling amount of adhesive. Even when the adhesive is set to a relatively large amount that is easy to work with, it is possible to reduce the amount overflowing from the recess and obtain substantially the same result as applying a very small amount of adhesive. it can. Therefore, it is possible to prevent the defective adhesion due to the outflow of the adhesive and the excessive adhesion due to it, and to prevent the defective braking due to the excessive penetration of the adhesive into the acoustic resistance sheet.

[0009]

【Example】

 FIG. 1 is an exploded perspective view of a piezoelectric receiver according to the present invention, and FIG. 2 is a sectional view taken along line A2-A2 of FIG. Reference numeral 1 is a case, 2 is a piezoelectric vibration plate, 3 is an adhesive, 4 is an acoustic resistance sheet, and 5 is an adhesive.

The case 1 has a ring-shaped internal space 11 and a hole 12. The hole 12 is provided in the wall portion 13 forming the internal space 11, and the wall portion 13 has a recess 14 around the hole 12. The case 1 is made of an appropriate material such as synthetic resin. In the figure, the wall portion 13 in which the hole 12 is provided constitutes the bottom portion of the internal space 11.

The piezoelectric vibrating plate 2 is peripherally supported on the case 1 so that a cavity 111 including a hole 12 is formed in the internal space 11. An end face 15 that supports the piezoelectric vibrating plate 2 on the periphery is formed on the ring around the inner space 11. The piezoelectric vibrating plate 2 is bonded onto the end surface 15 with an adhesive 3. The piezoelectric vibrating plate 2 includes a piezoelectric element 21 and a vibrating plate 22. The piezoelectric element 21 is attached to the one surface 221 side of the diaphragm 22. The piezoelectric element 21 has electrodes 212 and 213 on opposite sides of the piezoelectric ceramic 211.

The acoustic resistance sheet 4 is adhered to the wall portion 13 forming the bottom portion by the adhesive 5 filled in the recess 12 to close the hole 12. As described above, the acoustic resistance sheet 4 is made of a cloth of about several hundred mesh / inch. Lead wires 6 and 7 are connected to the electrodes 212 and 213 of the piezoelectric element 21, respectively.

As described above, the case 1 has the ring-shaped internal space 11, and the piezoelectric vibrating plate 2 is peripherally supported on the case 1 so that the cavity 111 is formed in the internal space 11. As a result, a piezoelectric receiver is obtained which converts the vibration of the piezoelectric diaphragm 2 due to the sound wave into an electric signal by the piezoelectric effect of the piezoelectric element 21 and outputs the electric signal.

Further, the case 1 has a hole 12, the hole 12 is provided in the wall portion 13 forming the internal space 11, and the piezoelectric vibrating plate 2 has a cavity 111 including the hole 12. The acoustic resistance sheet 4 is supported on the periphery above and is adhered to the wall portion 13 by the adhesive 5 to close the hole 12. Therefore, the acoustic resistance sheet 4 and the hole 12 provide an appropriate acoustic resistance braking, and the frequency characteristic Can be flattened and the frequency characteristics can be improved. FIG. 3 is a diagram showing frequency-sound pressure characteristics. In the figure, the horizontal axis represents the resonance frequency (kHz) and the vertical axis represents the sound pressure (dB). A curve L1 shows a resonance characteristic of the piezoelectric diaphragm, a curve L2 shows a cavity resonance characteristic of the case, and a curve L3 shows a combined characteristic in consideration of braking by the braking resistance sheet 4.

As shown in FIG. 3, the resonance frequency of the piezoelectric vibrating plate 2 and the resonance frequency of the cavity 111 are quite different from each other. However, by using the acoustic resistance sheet 4, the frequency characteristic is flattened. As a result, the frequency bandwidth is expanded.

Further, in the case 1, the wall portion 13 forming the internal space 11 has a recess 12 around the hole 12, and the acoustic resistance sheet 4 is covered with the adhesive 5 filled in the recess 12 to form the wall portion 13. Since the adhesive 12 is adhered to the concave portion 12, the concave portion 12 functions as a pool portion of the adhesive agent 5 and can absorb the fluctuation of the filling amount of the adhesive agent 5. Further, even when the adhesive 5 is set to a relatively large amount that is easy to work, the amount overflowing from the recess can be reduced, and substantially the same result as when a very small amount of adhesive is applied can be obtained. . Therefore, it is possible to prevent the defective adhesion due to the outflow of the adhesive and the excessive adhesion due to it, and it is possible to prevent the braking failure due to the excessive penetration of the adhesive 5 into the acoustic resistance sheet 4.

FIG. 4 is an exploded perspective view showing another embodiment of the piezoelectric receiver according to the present invention, and FIG. 5 is a front sectional view of the piezoelectric receiver shown in FIG.

Also in the embodiment of FIGS. 4 and 5, in the case 1, the wall portion 13 forming the internal space 11 has the recess 12 around the hole 12, and the acoustic resistance sheet 4 is filled in the recess 12. Since it is adhered to the wall portion 13 with the adhesive 5 applied, it is possible to obtain the operational effects for the actual highway of the embodiment shown in FIGS. 1 and 2. In addition, three projections 16 are provided on the end surface 15 at intervals. The protrusion 16 has a triangular shape, a square shape, another polygonal shape, or a semicylindrical shape, and three or more protrusions 16 are provided. A diaphragm 22 is arranged on the protrusion 16. With such a structure, three or more fulcrums necessary for stable support of the piezoelectric diaphragm 2 can be secured. Therefore, it is possible to stably support the piezoelectric vibrating plate 2 in a substantially horizontal state without tilting it and to secure a predetermined frequency characteristic. Further, since the vibration plate 22 is arranged on the protrusion 16 and adhered to the case 1 by the adhesive 3, the frequency characteristic, particularly the frequency characteristic in the low range, is improved.

[0019]

[Effect of device]

 As described above, according to the present invention, the following effects can be obtained. (A) The case has a ring-shaped internal space, and the piezoelectric vibrating plate is peripherally supported on the case so that a cavity is formed in the internal space. It is possible to provide a piezoelectric handset that is converted into an electric signal and output according to the effect. (B) The case has holes, and the holes are provided in the wall portion forming the internal space, and the piezoelectric vibrating plate is peripherally supported on the case so that a cavity including the holes is formed in the internal space. Since the acoustic resistance sheet is adhered to the wall portion with an adhesive to close the hole, it is possible to provide a piezoelectric handset capable of flattening the frequency characteristic. (C) In the case, the wall forming the internal space has a recess around the hole, and the acoustic resistance sheet is adhered to the wall by the adhesive filled in the recess. A piezoelectric receiver that can prevent braking failure due to jamming can be provided.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a piezoelectric receiver according to the present invention.

FIG. 2 is a sectional view of the piezoelectric receiver shown in FIG.

FIG. 3 is a diagram showing frequency-sound pressure characteristics of a piezoelectric receiver.

FIG. 4 is an exploded perspective view of another embodiment of the piezoelectric receiver according to the present invention.

5 is a cross-sectional view of the piezoelectric receiver shown in FIG.

[Explanation of symbols]

 1 Case 11 Internal Space 111 Cavity 12 Hole 13 Wall 14 Recess 2 Piezoelectric Vibration Plate 4 Acoustic Resistance Sheet

Claims (4)

[Scope of utility model registration request] 1. A piezoelectric receiver including a case, a piezoelectric vibrating plate, and an acoustic resistance sheet, wherein the case has a ring-shaped internal space and a hole, and the hole forms the internal space. The piezoelectric vibrating plate is provided on a wall and has a recess around the hole, and the piezoelectric vibrating plate has a peripheral portion on the case so that a cavity including the hole is formed in the internal space. A piezoelectric receiver in which the acoustic resistance sheet is supported and is adhered to the wall portion by an adhesive agent filled in the recess to close the hole. 2. The piezoelectric handset according to claim 1, wherein the acoustic resistance sheet is a braking cloth. 3. The piezoelectric receiver according to claim 1, wherein the hole is provided in a bottom wall portion of the case. 4. The case has a ring-shaped receiving surface around the internal space, and three or more protrusions are provided on the receiving surface at intervals, and the piezoelectric vibrating plate includes: The piezoelectric handset according to claim 1, wherein the piezoelectric handset is disposed on the protrusion and adhered to the receiving surface by an adhesive.