JPH09247795A - Piezoelectric transducer and sounding electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric transducer by decreasing the diametrical size of an adhered part of ribs (adhered face) so as to make the size smaller than that of a conventional transducer. SOLUTION: An adhesion face 10a and a tilt face 10b are formed to an outer side of a rib 10 of an insulation case 6 to mount a circumferential ridge 5e of a metallic diaphragm 5a. The tilt face 10b is formed to be a shape gradually parting from the circumferential ridge 5e of the metallic diaphragm 5a as going to the inside from the adhesion face 10a. the tilt angle 6 of the tilt face 10b is selected so as to form a sufficient adhesive agent layer between the rib 10 and the metallic diaphragm 5a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric transducer and a sound producing electronic device.

[0002]

2. Description of the Related Art Recently, miniaturization of sound producing electronic devices such as telephone handsets, mobile phones, wireless devices, radios, tape recorders, etc. has progressed, and along with this, piezoelectric devices used as sound producing elements of sound producing electronic devices. There is an increasing demand for miniaturization of converters. FIG. 4 is a schematic view showing an enlarged partial cross section of a conventional piezoelectric transducer used as a piezoelectric transducer for sound output of a handset of a mobile phone. In this conventional piezoelectric transducer, the piezoelectric vibrator 101 has an insulating case 102.
It is configured to be stored inside. Piezoelectric vibrator 101
Has a structure in which a vibrating element including a piezoelectric ceramic 104 having a diameter smaller than the diameter of the metal vibrating plate is bonded to the metal vibrating plate 103.

The insulating case 102 has a cylindrical peripheral wall 105.
And a disk-shaped bottom wall 106.
Although not shown, the bottom wall 106 has a leak hole. Ribs 107 for mounting the metal diaphragm 103 are formed on the inner wall portion of the peripheral wall 105. The rib 107 is formed as a step having a mounting surface (joint) 107 a on which the metal diaphragm 103 is mounted on the opening side of the insulating case 102. The back surface 10 of the metal diaphragm 103
3a peripheral edge 103b and insulating case 102 rib 107
The bonding portion 107a is bonded by an adhesive layer 109 formed of a silicone-based adhesive, whereby the piezoelectric vibrator 101 is fixed to the insulating case 102. With the piezoelectric vibrator 101 fixed to the insulating case 102, a rear air chamber S1 surrounded by the piezoelectric vibrator 101, the rib 107, and the bottom wall 106 is formed. The anterior chamber is
With the insulation case 102 attached to the mobile phone,
Outside of the piezoelectric vibrator 101 (opening 1 of the insulating case 102)
02a side).

The piezoelectric vibrator 101 is fixed to the insulating case 102 as follows. First, the joint 107 of the rib 107
After the adhesive is applied to a, the peripheral edge portion 103b is connected to the joint portion 1
The piezoelectric vibrator 101 is positioned so that it is positioned above the rib 07a.
7. Then, the metal vibrating plate 103 of the piezoelectric vibrator 101 is pressed against the rib 107 side to naturally cure the adhesive. In this way, the peripheral portion 103b and the joint portion 10 are
If the rear air chamber S1 and the space on the side of the opening 102a of the insulating case 102 (the space forming the front air chamber) are secured by joining the piezoelectric vibrator 101 to the insulating case 1a.
It can be fixed at 02. As a recent small-sized piezoelectric transducer, for example, a metal diaphragm 103 having a thickness of 50 μm,
The piezoelectric ceramic 104 designed to have a diameter of 20 mm and a thickness of 50 μm is manufactured.

[0005]

In this type of piezoelectric transducer, the diameter D1 of the portion excluding the joint portion N1 that joins the rib 107 of the metal diaphragm 103 substantially determines the natural resonance frequency of the metal diaphragm 103. It becomes the actual diameter to be determined. Therefore, when the size of the piezoelectric transducer having such a structure is further reduced, the distance (hereinafter, simply referred to as a radial dimension) of the joint portion 107a extending in the radial direction of the piezoelectric vibrator 101 is shortened to shorten the joint portion N1. However, it is possible to make the metal diaphragm smaller. However, when the radial dimension of the joint portion 107a is shortened, the joint area between the metal diaphragm 103 and the rib 107 is reduced, and the metal diaphragm 103 and the rib 1 are also reduced.
Since the adhesive layer with 07 becomes insufficient, the metal diaphragm 1
03 cannot be firmly supported by the rib 107. Therefore, conventionally, the joint portion 107a of the rib 107 is formed.
It was considered impossible to reduce the size of the piezoelectric converter by shortening the radial dimension of the.

An object of the present invention is to provide a piezoelectric transducer and a sound producing electronic device which can be made smaller than ever before.

Another object of the present invention is to provide a piezoelectric transducer and a sound producing electronic device which can be made smaller than the conventional one by reducing the radial dimension of the joint portion of the rib.

[0008]

According to the present invention, a piezoelectric vibrator, in which a piezoelectric ceramic is bonded to a metal vibrating plate, is housed inside a case, and a peripheral portion of the metal vibrating plate of the piezoelectric vibrator is an insulating case. The piezoelectric transducer is bonded to the joint portion on the outer surface of the rib provided on the inner wall portion of the peripheral wall by using an adhesive. In the present invention, the rib (or step) is configured such that the outer surface of the rib has an inclined surface that gradually separates from the metal diaphragm as it goes inward from the joint.

According to the present invention, when the uncured adhesive flows along the inclined surface of the rib in the direction of gradually separating from the metal vibrating plate when the piezoelectric vibrator and the case are joined together, the uncured adhesive is removed. It spreads inside along with the metal diaphragm. for that reason,
A sufficient amount of uncured adhesive is accumulated between the metal diaphragm and the rib, and a necessary and sufficient adhesive layer is formed between the metal diaphragm and the rib. Therefore, even if the radial dimension of the joint portion of the rib is shortened or the area of the joint portion is reduced, the adhesive layer of a sufficient thickness formed between the metal diaphragm and the rib causes the metal diaphragm to become a rib. It can be firmly fixed. As a result, it becomes possible to reduce the size of the piezoelectric transducer by shortening the radial dimension of the joint portion of the rib.

A plurality of protrusions are formed on the outer surface of the rib,
By placing a metal diaphragm on these protrusions,
It is also conceivable to increase the substantial diameter of the metal diaphragm.
However, with such a configuration, the substantial diameter of the metal diaphragm cannot be made sufficiently large, and the vibration mode may collapse.

In the specification of the present application, the "joint portion of the outer surface of the rib" is a portion on which the peripheral portion of the metal diaphragm is placed via an adhesive, and may be constituted by a surface extending parallel to the bottom surface of the case. Alternatively, it may be formed by a part of the inclined surface.

The inclined surface may be linearly inclined or curved so as to be curved. Such an inclined surface is inclined at an inclination angle capable of forming a sufficient adhesive layer between the metal diaphragm and the inclined surface. By doing so, the support of the ribs of the metal diaphragm is ensured.

The case may be composed of an insulating case having a peripheral wall and a bottom wall provided so as to substantially close one end of the peripheral wall. In this case, ribs are provided on the inner wall of the peripheral wall of the insulating case over almost the entire circumference integrally with the insulating case, and the peripheral edge of the back surface of the metal vibrating plate of the piezoelectric vibrator is bonded to the joint on the outer surface of the rib with an adhesive. To join.
Then, the rib is formed so that the outer surface of the rib has an inclined surface that inclines toward the bottom wall from the joint toward the center of the insulating case. Further, the inclined surface is inclined at an inclination angle that can form a sufficient adhesive layer between the metal diaphragm and the inclined surface. Specifically, when an imaginary horizontal plane including the inclination start point of the inclined plane and parallel to the bottom wall is assumed, the angle between the inclined plane and the imaginary horizontal plane is within the range of 45 ° ± 15 °. Incline. With this configuration, the metal diaphragm can be firmly fixed to the insulating case. When the inclined surface is inclined at an angle of less than 45 degrees -15 degrees (30 degrees), the inclined surface and the peripheral edge of the metal diaphragm come close to each other, so that the vibration of the peripheral edge of the metal diaphragm is suppressed and the metal diaphragm. The real diameter of can not be increased. If the inclined surface is inclined at an angle of more than 45 ° + 15 ° (60 °), the adhesive layer cannot be formed sufficiently and the metal diaphragm cannot be firmly fixed to the insulating case.

As the piezoelectric vibrator, a piezoelectric ceramic having a diameter smaller than that of the metal vibrating plate and having a pair of electrodes formed on both sides is joined to the metal vibrating plate, and lead wires are electrically connected to the pair of electrodes. It is possible to use the one configured by connecting.

As the insulating case, one having a cylindrical peripheral wall and a disc-shaped bottom wall can be used. In this case, a lead wire fitting groove into which a part of the lead wire is fitted is formed on the peripheral wall, and the peripheral edge portion of the metal diaphragm is continuously joined to the inner wall portion of the peripheral wall excluding the lead wire fitting groove. It is sufficient to form the step portion for joining the diaphragm. Then, the peripheral portion of the back surface of the metal diaphragm is joined to the outer surface of the diaphragm joining step portion with an adhesive having elasticity even when cured. The outer surface of the diaphragm joining step has a joining surface on which the peripheral edge of the metal diaphragm is placed, and an inclined surface that is inclined toward the bottom wall from the joining surface toward the center of the insulating case. To be formed.

The piezoelectric transducer may be included as a sounding element inside a sounding electronic device such as a mobile phone. In this case, the piezoelectric transducer may be attached to the housing so that the opening facing the bottom wall of the insulating case is covered by the wall of the housing. Then, with the piezoelectric transducer attached to the housing, a rib is formed at a position where the rear air chamber of the piezoelectric vibrator is formed, and the outer surface of the rib is directed toward the bottom wall as it is separated from the inner wall portion of the peripheral wall of the insulating case. It may be formed so as to have an inclined surface that inclines like this.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic diagram showing a partial cross section of a mobile phone (sound producing electronic device) that internally includes a piezoelectric transducer according to an embodiment of the present invention as a sound producing element (commonly called handset). As shown in FIG. 1, the mobile phone has a structure in which a piezoelectric transducer 2 is attached to an inner wall portion of a housing 1. The housing 1 has a structure in which a piezoelectric transducer mounting rib 4 is formed on an inner wall portion of a housing body 3. The piezoelectric transducer mounting rib 4 has a cylindrical shape and is formed integrally with the housing body 3. The piezoelectric transducer mounting rib 4 has a step portion 4a on the inner wall portion.
The piezoelectric transducer 2 is fitted in the stepped portion 4a so that the opening 6a of the piezoelectric transducer 2 faces the housing 1, that is, the opening 6a is covered by the wall of the housing 1.
In this state, a front air chamber is formed between the wall of the housing 1 and the piezoelectric vibrator 5.

The piezoelectric transducer 2 is constructed by housing a piezoelectric vibrator 5 inside an insulating case 6. Piezoelectric vibrator 5
As shown in the schematic diagram showing the partial cross section of FIG. 2, a piezoelectric ceramic 5c having a diameter smaller than the diameter of the metal vibration plate 5a and a pair of electrodes 5b, 5b formed on both sides is bonded to the metal vibration plate 5a. Is configured. In this embodiment, the metal vibrating plate 5a has a thickness of 50 μm and a diameter of 16 mm, and the piezoelectric ceramic 5c has a thickness of 50 μm and a diameter of 11.
It is formed to have a size of 3 mm. As shown in FIG. 1, one ends of lead wires 7, 7 are electrically connected to the pair of electrodes 5b, 5b, respectively. In FIG. 2, the thickness of each part is exaggerated for easy understanding.

The insulating case 6 is integrally molded of insulating resin and has a cylindrical peripheral wall 8 and a disc-shaped bottom wall 9 provided so as to substantially close one end of the peripheral wall 8. have. The peripheral wall 8 is formed with a lead wire fitting groove 8a (FIG. 1) into which the lead wires 7, 7 are partially fitted. The peripheral wall 8 of the peripheral wall 8 excluding the lead wire fitting groove 8a is formed. A diaphragm joining step or rib 10 is integrally formed on the inner wall portion 8b continuously in the circumferential direction. This rib 1
The outer surface of 0 is located below the metal vibrating plate 5a and forms a joint to which the peripheral edge 5e of the metal vibrating plate 5a is joined, and the inclined surface 1 formed continuously with the joint surface 10a.
0b and a cut surface 10c continuous to the inclined surface 10b and extending vertically toward the bottom wall 9. Bonding surface 10
The dimension a is such that the peripheral portion 5e of the metal diaphragm 5a is slightly placed. In this embodiment, the joint surface 10a is formed so that the dimension of the metal diaphragm 5a extending in the radial direction is 0.3 to 0.5 mm. The inclined surface 10b has a shape that gradually separates from the peripheral edge portion 5e of the back surface 5d of the metal diaphragm 5a from the joint surface 10a toward the inside of the piezoelectric transducer.
More specifically, the inclined surface 10b is the joint surface 10
It has a shape that linearly inclines toward the bottom wall 9 from a toward the center of the insulating case 6 or the center of the metal vibrating body 5a.

In the present embodiment, the angle between the imaginary horizontal plane parallel to the bottom wall 9 including the inclination start point of the inclined surface 10b (the surface substantially matching the back surface 5d of the metal diaphragm 5a) and the inclined surface 10b ( The ribs are formed by linearly inclining the inclined surface 10b so that the inclination angle θ is in the range of 45 ° ± 15 °. Inclined surface 10b inclined at an angle within this angle range
Can form a necessary and sufficient adhesive layer between the metal diaphragm 5a and the inclined surface 10b. Edge 5e of metal diaphragm 5a
And the joint surface 10a and the inclined surface 10b of the rib 10 are joined by the adhesive layer 11, so that the piezoelectric vibrator 5 has the insulating case 6
Fixed to The adhesive layer 11 is preferably formed of an adhesive that has elasticity even when cured. In this example, an adhesive layer 1 was prepared by using a one-component solventless solventless alcohol type adhesive of model 1220 sold by ThreeBond Co., Ltd.
1 was formed. Then, in a state where the piezoelectric vibrator 5 is housed inside the insulating case 6, a rear air chamber S1 of the piezoelectric vibrator 5 surrounded by the piezoelectric vibrator 5, the rib 10 and the bottom wall 9 is formed. As shown in FIG. 1, a leak hole 9a is formed in the central portion of the bottom wall 9. The leak hole 9 is covered with a cloth of a predetermined mesh in order to dump the inflow and outflow of air and adjust the characteristics. ing.

In this example, the piezoelectric vibrator 5 was fixed to the insulating case 6 as follows. First, the joint surface 1 of the rib 10
0a and the inclined surface 10b and the lead wire fitting groove 8a in the vicinity of the boundary, and then the peripheral edge 5e is bonded to the joint surface 10
The piezoelectric vibrator 5 is placed on the rib 10 so as to be located on a. Then, the metal diaphragm 5a of the piezoelectric vibrator 5 is attached to the rib 1
After pressing on the 0 side, an adhesive was further applied so as to fill the lead wire fitting groove 8a, and then the adhesive was naturally cured to form the adhesive layer 11. As a result, the peripheral portion 5e
And the bonding surface 10a of the rib 10 are bonded to each other, and the adhesive layer 11 ensures the airtightness between the rear air chamber S1 and the space (front air chamber) on the side of the opening 6a of the insulating case 6, and the piezoelectric vibrator 5
Was fixed to the insulating case 6.

In the piezoelectric transducer of this embodiment, the piezoelectric vibrator 5
When the uncured adhesive flows along the inclined surface 10b of the rib 10 in a direction of gradually separating from the peripheral edge portion 5e of the metal vibration plate 5a when joining the case 6 and the case 6, both of the uncured adhesive are generated. Spread inward along with. Therefore, the necessary and sufficient adhesive layer 11 can be formed between the metal diaphragm 5a and the rib 10. Therefore, even if the radial dimension of the outer joint surface 10a of the rib 10 is shortened to shorten the joint portion N2, an uncured adhesive agent having a sufficient thickness formed between the metal diaphragm 5a and the rib 10 is formed. By the layer of the metal diaphragm 5
It becomes possible to firmly fix a to the rib 10.
As a result, the diameter of the metal vibrating plate 5a can be made smaller than in the conventional case by the amount that the radial dimension is shortened (the amount of the joint portion is shortened: the dimension obtained by subtracting N2 of FIG. 2 from N1 of FIG. 4).

Next, using a piezoelectric vibrator having a metal diaphragm with a diameter of 16 mm, the inclination angle θ of the joint surface of the insulating case is changed, and the natural resonance frequency of the metal diaphragm is measured. The relationship with the resonance frequency was investigated. Table 1
Indicates the measurement result.

[Table 1] From Table 1, the inclination angle is 45 degrees ± 15 degrees (30 to 60 degrees)
It can be seen that, when the range is set to, the natural resonance frequency which is almost the same as the natural resonance frequency obtained by designing the diameter of the metal diaphragm to be 20 mm in the conventional piezoelectric transducer having the structure shown in FIG. 4 can be obtained. Therefore, according to this embodiment, the inclination angle is set to 45.
It can be seen that by setting the degree to ± 15 degrees (30 to 60 degrees), the diameter of the metal diaphragm having a diameter of 20 mm can be reduced to 16 mm. If the inclination angle exceeds 45 ° + 15 ° (= 60 °), the adhesive layer cannot be formed sufficiently and the metal diaphragm cannot be firmly fixed to the insulating case.

FIG. 3 is a partial sectional view showing another embodiment of the piezoelectric converter of the present invention. This embodiment is different from the example shown in FIG. 2 in that the joint portion is constituted by a taper portion which is inclined with respect to the metal diaphragm 15a, and other points are almost the same as the previous example. is there. Therefore, the same parts as those in the example of FIG. 2 are denoted by the reference numerals of FIG. 2 plus 10, and the description thereof is omitted. In this embodiment, the rib 2
0 of the joint portion 20a is continuous with the inclined surface 20b and the inclined surface 2
It is formed by a tapered portion having the same inclination angle as 0b. In other words, in this embodiment, the metal diaphragm 15 is used.
a, a taper surface is formed so as to be continuously inclined from the inner wall portion 18b of the peripheral wall 18 without providing a surface for horizontally mounting the metal vibration plate 15a. The corner portion 15f and a so-called line-joining portion form a joint portion 20a.

In each of the above embodiments, the inclined surface 10b,
Although the rib is formed by linearly inclining 20b, the inclined surface may be curved and the inclined surface may be formed by a curved surface.

In each of the above embodiments, the insulating case 6, 1
6 side (near the boundary between the joints 10a, 20a of the ribs 10, 20 and the inclined surfaces 10b, 20b and the lead wire fitting groove 8)
The piezoelectric vibrators 5 and 15 were fixed to the insulating cases 6 and 16 by applying an adhesive to a), but the airtightness between the rear air chamber S1 and the spaces on the side of the openings 6a and 16a of the insulating cases 6 and 16 was determined. As long as the piezoelectric vibrators 5 and 15 can be fixed to the insulating cases 6 and 16 by increasing the adhesive strength, an adhesive may be applied to at least one of the insulating cases 6 and 16 side and the piezoelectric vibrators 5 and 15 side. An adhesive may be applied to both the insulating cases 6 and 16 side and the piezoelectric vibrators 5 and 15 side or to the piezoelectric vibrators 5 and 15 side.

[0027]

According to the present invention, when the uncured adhesive flows along the inclined surface of the rib in the direction of gradually separating from the metal diaphragm when the piezoelectric vibrator and the case are joined together, the uncured adhesive is adhered to both. The agent spreads inward along the metal diaphragm. Therefore, a sufficient amount of uncured adhesive agent is accumulated between the metal diaphragm and the rib, and a necessary and sufficient adhesive layer is formed between the metal diaphragm and the rib. Therefore, even if the radial dimension of the joint portion of the rib is shortened or the area of the joint portion is reduced, the adhesive layer of a sufficient thickness formed between the metal diaphragm and the rib causes the metal diaphragm to become a rib. It can be firmly fixed. As a result, it becomes possible to reduce the size of the piezoelectric transducer by shortening the radial dimension of the joint portion of the rib.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a mobile phone (sound producing electronic device) that internally includes, as a sound producing element, a piezoelectric transducer according to an example of an embodiment of the present invention.

FIG. 2 is a schematic view showing a partial cross section of a piezoelectric transducer according to an example of an embodiment of the present invention.

FIG. 3 is a schematic view showing a partial cross section of a piezoelectric transducer according to another example of the embodiment of the present invention.

FIG. 4 is a schematic view showing a partial cross section of a conventional piezoelectric transducer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 2 Piezoelectric transducer 5 Piezoelectric vibrator 5a Metal vibrating plate 5b Electrode 5c Piezoelectric ceramic 5d Back surface 5e Peripheral part 6 Insulating case 8 Peripheral wall 8a Fitting groove 8b Inner wall part 9 Bottom wall 10 Vibrating plate bonding step (rib) 10a Bonding surface (bonding portion) 10b Inclined surface 11 Adhesive layer

Claims (7)

[Claims] 1. A piezoelectric vibrator, in which a piezoelectric ceramic is bonded to a metal vibrating plate, is housed inside a case, and a peripheral portion of the metal vibrating plate of the piezoelectric vibrator is an inner wall portion of a peripheral wall of the insulating case. A piezoelectric transducer bonded to an outer surface of a rib provided on the outer surface of the rib using an adhesive, wherein the outer surface of the rib gradually extends from the metal diaphragm toward the inner side of the joint. A piezoelectric transducer having an inclined surface which is separated. 2. A piezoelectric vibrator having a piezoelectric ceramic bonded to a metal vibrating plate is housed inside an insulating case having a peripheral wall and a bottom wall provided so as to substantially close one end of the peripheral wall. A rib is integrally provided on the inner wall portion of the peripheral wall of the insulating case over substantially the entire circumference, and the peripheral edge portion of the back surface of the metal vibrating plate of the piezoelectric vibrator is bonded to the joint portion of the outer surface of the rib with an adhesive. A piezoelectric transducer that is joined, wherein the outer surface of the rib has an inclined surface that is inclined toward the bottom wall from the joined portion toward the center of the insulating case. And a piezoelectric transducer. 3. The piezoelectric converter according to claim 1, wherein the inclined surface is inclined at an inclination angle capable of forming a necessary and sufficient adhesive layer between the metal diaphragm and the inclined surface. 4. The angle between the inclined plane and the virtual horizontal plane falls within a range of 45 ° ± 15 ° when a virtual horizontal plane including the inclination start point of the inclined plane and parallel to the bottom wall is assumed. The piezoelectric converter according to claim 3. 5. A piezoelectric ceramic having a thickness of 50 μm or less and a diameter of less than 20 mm is bonded to a piezoelectric ceramic having a thickness of 50 μm or less and having a diameter smaller than the diameter of the metal diaphragm and having a pair of electrodes formed on both sides. A piezoelectric vibrator having lead wires electrically connected to the pair of electrodes, and a flat insulating case in which the piezoelectric vibrator is housed. The insulating case has a cylindrical peripheral wall. And a disc-shaped bottom wall, a lead wire fitting groove into which a part of the lead wire is fitted is formed on the peripheral wall, and an inner wall portion of the peripheral wall excluding the lead wire fitting groove is formed. Is continuously formed with a diaphragm-bonding step portion to which the peripheral edge of the metal diaphragm is bonded. The back edge of the metal diaphragm is bonded A piezoelectric transducer, wherein the outer surface of the diaphragm bonding step is a bonding surface on which the peripheral edge of the metal diaphragm is placed, and the outer surface of the diaphragm moves toward the center of the insulating case from the bonding surface. A piezoelectric transducer having an inclined surface inclined toward the bottom wall and inclined at an angle capable of forming a necessary and sufficient adhesive layer with the metal diaphragm. 6. The angle between the inclined surface and the virtual horizontal plane is within a range of 45 ° ± 15 ° when a virtual horizontal plane including the joint surface and parallel to the bottom wall is assumed. The piezoelectric transducer described. 7. A piezoelectric vibrator in which a piezoelectric ceramic is bonded to a metal vibrating plate is housed inside an insulating case composed of a peripheral wall and a bottom wall provided on one end side of the peripheral wall, and the peripheral wall of the insulating case is provided. A rib is integrally provided on the inner wall portion, and a peripheral portion of the back surface of the metal vibrating plate of the piezoelectric vibrator is joined to the outer surface of the rib via an adhesive. A sound producing electronic device included inside, wherein the piezoelectric transducer is attached to the housing such that an opening portion of the insulating case facing the bottom wall is covered by a wall portion of the housing. The case has the rib at a position where the vibration space of the piezoelectric vibrator is formed in a state where the piezoelectric transducer is attached to the housing, and the outer surface of the rib is the inner wall portion or the inner wall portion. A sounding electronic device having an inclined surface which is inclined toward the bottom wall as the distance from the metal diaphragm is increased, and is inclined at an angle capable of forming a necessary and sufficient adhesive layer with the metal diaphragm. .