JP3044460U - Piezoelectric acoustic components and devices - Google Patents

Abstract

(57) Abstract: A circuit board is not adversely affected by deformation such as bending, and a case having a piezoelectric element is easily attached to an electronic device, which is an obstacle to high-density mounting of the circuit board. Obtain piezoelectric acoustic components and devices that do not A piezoelectric acoustic component includes a vibrating plate having a metal plate shape.
The piezoelectric element 22 has a piezoelectric body 22 fixed to the main surface thereof, and an electrode 23 is provided on the surface of the piezoelectric body 22, and a case 1 that houses the piezoelectric element 2 and forms a resonance chamber. On the outer circumference of the case 1, there is provided a jaw-shaped engaging portion 41 with which the tip of a fixing projection 34 having a hook-shaped tip side surface protruding from the inner surface of the housing 31 of the device to which the case 1 is attached is engaged. ing. The engagement portion 41 is formed by a projecting or concave step portion provided over the entire circumference or a part of the circumference of the case 1. Case 1 and housing 3 of this piezoelectric acoustic component
In a state where the elastic member 35 is sandwiched between the housing 1 and the housing 1, the jaw-shaped engaging portion 41 provided on the outer circumference of the case 1 is attached to the housing 3 of the device.
The tip end of the fixing projection 34 having a hook-shaped tip side surface projecting on the inner surface of 1 is engaged. As a result, the case 1 is attached to the housing 31.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention relates to a piezoelectric acoustic component that uses a piezoelectric element and is used as an acoustic device such as a receiver of a telephone or other communication device, and a piezoelectric acoustic device that uses the piezoelectric acoustic component.

[0002]

[Prior art]

 As shown in FIGS. 9 and 10, a conventional piezoelectric acoustic component uses a tray-shaped case 1 having a stepwise piezoelectric element supporting portion 6 in an intermediate portion inside a peripheral wall 5, and the inside of this case 1 is used. The piezoelectric element 2 is housed in the piezoelectric element 2, and the peripheral portion of the vibration plate 21 is placed on the piezoelectric element supporting portion 6 and fixed with an adhesive. In the piezoelectric element 2, a piezoelectric body 22 is fixed to one or both main surfaces of a vibration plate 21 having a metal plate shape, and an electrode 23 is formed on the surface of the piezoelectric body 22. A lead wire 17 is connected to each of the electrode 23 on the piezoelectric body 22 and the diaphragm 21, and the lead wire 17 is led out from the case 1 to the outside. In the illustrated example, the piezoelectric body 22 is fixed to one main surface of the diaphragm 21 with an adhesive (not shown) or the like. Further, a damper 11 having a sound emitting hole meshed with is formed in the center of the bottom wall of the case 1.

Such a piezoelectric acoustic component is incorporated in an electronic device such as a mobile phone or a so-called cordless phone. In this case, considering the exchangeability in case of failure, it is stored and installed in the housing of the electronic device. Further, the lead wires are connected to the circuit board in the housing by soldering or the like. In such a conventional piezoelectric acoustic component, particularly in a small piezoelectric acoustic component in which the diameter of the piezoelectric element 2 is 20φ or less, the vibration generated in the diaphragm 21 escapes to the case 1 and the sound pressure level becomes small. There were challenges. This is because the mass of Case 1 has decreased. Therefore, a structure has been proposed between the circuit board and the housing so as to press the case.

FIG. 10 shows an example in which such a piezoelectric acoustic component is mounted in a housing 31 of an electronic device to form a piezoelectric acoustic device. A circumferential mounting portion 45 having an inner diameter corresponding to the outer diameter of the case 1 is provided around the sound emitting hole from the inner surface of the wall portion of the housing 31 where the sound emitting hole 32 is provided. The case 1 of the audio component 1 is fitted. The case 1 has its bottom wall side fitted into the mounting portion 45 toward the inner surface of the housing 31, and the ring-shaped elastic member 35 is inserted between the bottom surface of the case 1 and the inner surface of the housing 31. Further, the circuit board 36 having the pressing component 38 attached to the lower surface is mounted on the case 1 of the piezoelectric acoustic component, and the case 1 is sandwiched between the pressing component 38 of the circuit substrate 36 and the housing 31. . In this state, the lead wire 17 is connected to a predetermined circuit pattern on the circuit board 36. In FIG. 10, reference numeral 39 indicates a circuit component mounted on the circuit board 36.

[0005]

[Problems to be solved by the invention]

 However, in the case of the piezoelectric acoustic device as described above, since the circuit board 36 presses the case 1 of the piezoelectric acoustic component to the housing 31 via the pressing component 38, the portion of the circuit board 36 to which the pressing component 38 is attached. It is not possible to mount a circuit component or form a circuit pattern or the like for connecting the piezoelectric element 2 on. Therefore, it hinders high-density mounting of the circuit board 36.

Further, when the case 1 is pressed down by the circuit board 36, the circuit board 36 is bent, which may cause a trouble such as disconnection of a circuit pattern formed on the circuit board 36. Moreover, in addition to the piezoelectric acoustic component, the height of the pressing component 38 and the circuit board 36 is added, so that the height of the portion that constitutes the piezoelectric acoustic device as a whole becomes high, which makes it difficult to reduce the size. is there.

In view of the above-mentioned conventional problems, the present invention does not adversely affect the circuit board due to deformation such as bending, and moreover, the case in which the piezoelectric element is attached can be easily attached to the electronic device. Provided are a piezoelectric acoustic component and a device which do not hinder high-density mounting of the device. This makes it possible to easily assemble electronic devices, reduce defects, and incorporate them in compacts.

[0008]

[Means for Solving the Problems]

 In the present invention, in order to achieve the above-mentioned object, a jaw-shaped engaging portion 41 is provided on the outer periphery of the case 1 to which the piezoelectric element 2 is attached, and the engaging portion 41 has a tip side surface protruding from the inner surface of the housing 31. By engaging and fixing the tips of the hook-shaped fixing protrusions 34, the case 1 of the piezoelectric acoustic component is not pressed by the circuit board 36, but the case 1 is pressed against the housing 31. I made it possible to attach it to 31.

That is, in the piezoelectric acoustic component according to the present invention, the piezoelectric body 22 is fixed to the main surface of the diaphragm 21 having a metal plate shape, and the electrode 23 is provided on the surface of the piezoelectric body 22, and the piezoelectric element 2. And a case 1 for accommodating the element 2 and forming a resonance chamber, for fixing the outer peripheral surface of the case 1 projecting from the inner surface of the housing 31 of the device to which the case 1 is attached It is characterized in that a jaw-shaped engaging portion 41 with which the tip of the protrusion 34 is engaged is provided. The engaging portion 41 is formed by a projecting or concave step portion provided over the entire circumference or a part of the circumference of the case 1.

A piezoelectric acoustic device using such a piezoelectric acoustic component and incorporating it into a housing 31 of a device has a jaw-shaped engaging portion 41 provided on the outer periphery of the case 1 and an inner surface of the housing 31 of the device. The case 1 is attached to the housing 31 by engaging the tips of the fixing projections 34 having the hook-like side surfaces of the tips protruding from the case 1. In this case, the elastic member 35 is sandwiched between the case 1 and the housing 31, and the case 1 is pressed against the housing 31 via the elastic member 35. In this piezoelectric acoustic device, the piezoelectric element 2 and the circuit pattern of the circuit board 36 can be connected in various forms.

For example, the vibration plate 21 of the piezoelectric element 2 and the extraction electrode 15 that is extracted from the electrode 23 on the surface of the piezoelectric body 22 to the vibration plate 21 in an insulating state are connected to the elastic connection block 12. .. are respectively connected to the circuit patterns of the circuit board 36 mounted in the housing 31 through the provided conductor portions 16, 16. In this case, the connection block 12 is sandwiched between the circuit board 36 mounted in the housing 31 and the piezoelectric element 2 in a state where compressive stress is applied.

Further, for example, the vibrating plate 21 of the piezoelectric element 2 and the electrode 23 on the surface of the piezoelectric body 22 are connected to the leaf spring-like terminals 38, 38, and the tips of the terminals 38, 38 are the housing 31. By making contact with the circuit patterns of the circuit board 36 mounted therein, they are electrically connected. In this case, the leaf-spring-shaped terminals 38, 38 are sandwiched between the circuit board 36 mounted in the housing 31 and the piezoelectric element 2 in a state in which a bending stress is applied.

In such a piezoelectric acoustic component and device, the housing 31 can press the case 1 against the housing 31 by the fixing protrusion 34 itself without using other members such as the circuit board 36. As a result, it is not necessary to press the case 1 of the piezoelectric acoustic component by the circuit board 36, the piezoelectric acoustic component can be easily incorporated, and the circuit substrate 36 is not deformed such as bent. Further, since the circuit board 36 can be mounted separately from the piezoelectric acoustic component, it is possible to form a circuit pattern on the surface of the circuit substrate 36 facing the piezoelectric acoustic component or to mount the circuit component. It does not hinder high-density mounting.

[0014]

[Embodiment of the invention]

 Next, embodiments of the present invention will be described specifically and in detail with reference to the drawings. 1 and 2 show an example of a piezoelectric acoustic component according to the present invention and a piezoelectric acoustic device assembled using the same. In the piezoelectric element 2, a piezoelectric body 22 is fixed to the main surface of a diaphragm 21 having a metal plate shape, and an electrode 23 made of a metal film is formed on the surface of this piezoelectric body. The protrusion 3 is provided so as to protrude from the peripheral portion of the diaphragm 21, and the illustrated protrusion 3 is protruded in the radial direction of the diaphragm 21. A strip-shaped insulating layer 14 is formed from the electrode 23 of the piezoelectric body 22 to the protrusion 3, and a strip-shaped lead-out electrode 15 made of a conductive film is formed on the insulating layer 14. The extraction electrode 15 extends beyond the edge of the end of the insulating layer 14 on the electrode 23 side of the piezoelectric body 22 and is electrically connected to the electrode 23. The insulating layer 14 and the extraction electrode 15 are formed so as to be biased to one side of the protrusion 3, and the metal surface of the diaphragm 21 is exposed on the other side of the protrusion 3.

The case 1 for accommodating and mounting the piezoelectric element 2 is in the shape of a circular tray having an open upper surface, and is made of a plastic molded body. An electrode support portion 4 is projectingly provided on a part of the peripheral wall 5 of the case 1. The electrode supporting portion 4 is a groove-like member having an inner dimension corresponding to the dimension of the protrusion 3 projecting from the peripheral portion of the vibration plate 21 of the piezoelectric element 2, and the diameter of the electrode supporting portion 4 from the outer peripheral portion of the case 1. Protruding in the direction. A step portion 6 for supporting the peripheral portion of the vibration plate 21 of the piezoelectric element 2 is formed in an intermediate portion in the height direction of the inner surface of the peripheral wall 5 of the case 1, and the upper surface of the step portion 6 has the electrode supporting portion 4 It is flush with. The outer diameter of the step portion 6 is larger than the diameter of the diaphragm 21 of the piezoelectric element 2, and the inner diameter of the step portion is smaller than the diameter of the diaphragm 21 of the piezoelectric element 2.

A braking hole is formed in the center of the bottom wall of the case 1, and a mesh made of Tetlon mesh or the like is stretched inside the braking hole to form a damper 11. The damper 11 can be selected from various shapes depending on the sound pressure characteristic to be obtained, and can also be constituted by a plurality of small-diameter braking holes, for example. Further, an engaging portion 41 is provided so as to project from the outer circumference of the case 1. As is apparent from FIG. 2, the engaging portion 41 is a jaw-like member that protrudes outward from the outer peripheral surface of the peripheral wall of the case 1, the upper surface of which is parallel to the bottom surface of the case 1 and the lower portion thereof. Has a taper shape with a gradually decreasing diameter. In the example shown in FIGS. 1 and 2, three engaging portions 41 are provided at 120 ° intervals.

The piezoelectric element 2 is incorporated in the case 1 as follows. First, an adhesive agent such as a silicone-based adhesive agent is uniformly applied in advance along the step 6 on the inner peripheral side of the peripheral wall 5 of the case 1 having the damper 11. Next, the piezoelectric element 2 is housed inside the case 1 with the piezoelectric body 22 side facing up, and the peripheral portion of the diaphragm 21 of the piezoelectric element 2 is placed on the stepped portion 6. In this state, by curing the adhesive, the peripheral portion of the diaphragm 21 is adhered and fixed by the adhesive. At this time, the protrusion 3 is fitted into the electrode support portion 4 of the case 1.

The case 1 to which the piezoelectric element 2 is attached in this manner is attached to the inside of the housing 31 of the electronic device. The wall of the housing 31 is provided with a sound emitting hole 32 for emitting the sound generated by the piezoelectric element 2 to the outside. The sound emitting hole 32 is surrounded by the inner surface of the housing 31 and the tip side surface thereof has a hook shape. The fixing projections 34 are provided so as to project. The fixing projections 34 are provided corresponding to the engaging portions 41 of the case 1. Therefore, in the example of FIGS. 1 and 2, three fixing projections 34 surround the sound output hole 32 at 120 ° intervals. The fixing projection 34 is arranged. The hook-shaped tips of the fixing projections 34 are arranged on a circle having the same diameter as the engaging portion 41 of the case 1.

Then, a ring-shaped elastic member 35 is placed on the inner surface portion of the housing 31 surrounded by the fixing projections 34, the case 1 of the piezoelectric vibration component is further fitted into the fixing projections 34, and the housing 31 is attached to the housing 31. Push in toward. At this time, the tip of the fixing projection 34 is expanded by the taper of the lower surface of the engaging portion 41, and when the tip of the fixing projection 34 reaches the flat upper surface of the engaging portion 41, the engaging projection 34 The tip of 34 fits into that part. At the same time, the elastic member 35 is compressed, and is sandwiched between the bottom surface of the case 1 and the inner surface of the housing 31 in a state where a compressive stress is applied. As a result, the piezoelectric acoustic component is mounted inside the housing 31. In this state, the damper 11 of the case 1 of the piezoelectric acoustic component faces the sound output hole 32 of the housing 31.

Further, this piezoelectric acoustic component is housed in the housing via the conductor portions 16, 16 provided on the connecting block 12 in which the projection 3 of the diaphragm 21 and the extraction electrode 15 are elastic. The circuit patterns (not shown) on the attached circuit board 36 are respectively connected. The connecting block 12 is, for example, one shown in Japanese Patent Publication No. 56-48951, or an elastic block commercially available under the trade name of "interconnector". For example, the insulating portions 13 and the conductor portions 16 are alternately arranged at a constant pitch on at least the surface of the elastic body. For example, a layered body in which an insulator having a certain thickness having elasticity and a conductor having a certain thickness having elasticity are alternately laminated, or the surface of a block made of an elastic material is metallized into a band shape at regular intervals. Made by.

In the above-described piezoelectric acoustic device, the extraction electrode 15 provided on the protrusion 3 of the diaphragm 21 and the surface of the protrusion 3 are connected to the circuit pattern of the circuit board 36 by using the connecting block 12 having elasticity. Since they are connected, soldering of lead wires is unnecessary. The case 1 with the piezoelectric element 2 attached is clamped inside the housing 31 of the electronic device by the engagement between the fixing projection 34 and the engaging portion 41, so that the case 1 can be fixed with screws or the like. It becomes unnecessary. Further, it is not necessary to directly press the case 1 to which the piezoelectric element 2 is attached by the circuit board 36.

Since the connecting block 12 is an elastic block in which at least a plurality of conductor portions 16, 16 ... Are arranged on the surface so as to be insulated from each other at regular intervals, the electrode support portion of the case 1 is provided. If a compressive stress is applied and sandwiched between the protrusion 3 supported by the circuit board 4 and the circuit board 36, the diaphragm 21 and the electrode 23 of the piezoelectric body 22 can be easily connected to the circuit pattern of the circuit board 36. .

Next, FIG. 3 and FIG. 4 show another example of the piezoelectric acoustic device according to the present invention and a piezoelectric acoustic device assembled using the same. In the above-mentioned example, the jaw-like engaging portion 41 provided on the outer periphery of the case 1 is composed of the projecting step portion projecting from the outer periphery of the case 1, but in this example, the engaging portion 41 is the case 1. It is composed of a concave step formed on the outer periphery of the. Three such engaging portions 41 are provided at intervals of 120 °, a point at which a hook-shaped fixing projection 34 protruding from the inner surface of the housing 31 engages with the engaging portion 41, and elasticity. 1 and FIG. 2 that the extraction electrode 12 provided on the protrusion 3 of the diaphragm 21 and the surface of the protrusion 3 are connected to the circuit pattern of the circuit board 36 by using the connection block 12 having The same as the example shown in.

5 and 6 show another example of the piezoelectric acoustic component according to the present invention and a piezoelectric acoustic device assembled using the same. In the above example, the jaw-shaped engaging portions 41 provided on the outer circumference of the case 1 are provided at three locations at 120 ° intervals, but in this example, the engaging portions 41 are entirely on the outer circumference of the case 1. It consists of a step formed around the circumference. On the other hand, the three fixing projections 34 on the housing 31 side that engage with the engaging portions 41 are provided at 120 ° intervals.

The point at which the fixing projection 34 engages with the engaging portion 41, and the surface of the extraction electrode 12 and the projection 3 provided on the projection 3 of the diaphragm 21 using the elastic connecting block 12 The points connected to the circuit pattern of the circuit board 36 are the same as the examples shown in FIGS. 1 and 2. It should be noted that the engaging portion 41 composed of a concave step portion as shown in FIGS. 3 and 4 can be provided over the entire outer circumference of the case 1 as in the examples shown in FIGS. 5 and 6. Needless to say.

7 and 8 show another example of the piezoelectric acoustic component according to the present invention and a piezoelectric acoustic device assembled using the same. The fixing means of the case 1 to the housing 31 in this example is the same as the example shown in FIGS. 1 and 2, but the connecting means of the piezoelectric element 2 to the circuit board 36 is different. That is, the bases of leaf spring-shaped terminals 49, 49 made of elastic metal plates and the like connected to the vibration plate 21 of the piezoelectric element 2 and the electrodes 23 on the surface of the piezoelectric body 22 are the electrode supporting portions of the case 1. It is fixed at 4. Near the bases of the terminals 49, 49, the tip ends thereof are bent at an acute angle so as to reach the upper center of the case 1. The tips of the terminals 49, 49 are brought into contact with the lower surface of the circuit board 36 by its elasticity and are connected to the circuit pattern formed therein. The other points are the same as the examples shown in FIGS. 1 and 2, but in the example shown in FIGS. 3 and 4 or the examples shown in FIGS. Alternatively, it goes without saying that the piezoelectric element 2 and the circuit board 36 can be connected to each other by using the leaf spring-shaped terminals 49, 49 of such a metal plate.

[0027]

[Effect of the invention]

 As described above, according to the present invention, it is not necessary to press the case 1 of the piezoelectric acoustic component by the circuit board 36, the piezoelectric acoustic component can be easily incorporated, and the entire mounting portion can be downsized. Further, the circuit board 36 does not undergo deformation such as bending, and troubles such as disconnection of the circuit pattern are less likely to occur. Further, since the circuit board 36 can be mounted separately from the piezoelectric acoustic component, it is possible to form a circuit pattern on the surface of the circuit substrate 36 facing the piezoelectric acoustic component or to mount the circuit component. High-density mounting of the board can be achieved.

[Brief description of the drawings]

FIG. 1 is a plan view of an essential part of a piezoelectric acoustic device according to the present invention with a circuit board removed.

FIG. 2 is a vertical cross-sectional view taken along the line AA of FIG. 1 in a state in which a circuit board of the example of the piezoelectric acoustic device is attached.

FIG. 3 is a plan view of a main part of a piezoelectric acoustic device according to another embodiment of the present invention with a circuit board removed.

FIG. 4 is a vertical cross-sectional view taken along the line AA of FIG. 1 in a state in which a circuit board of the example of the piezoelectric acoustic device is attached.

FIG. 5 is a plan view of a principal part of a piezoelectric acoustic device according to another embodiment of the present invention with a circuit board removed.

FIG. 6 is a vertical cross-sectional view taken along the line AA of FIG. 1 in a state in which a circuit board of the example of the piezoelectric acoustic device is attached.

FIG. 7 is a plan view of a principal part of a piezoelectric acoustic device according to another embodiment of the present invention with a circuit board removed.

FIG. 8 is a vertical cross-sectional view taken along the line AA of FIG. 1 in a state in which a circuit board of the example of the piezoelectric acoustic device is attached.

FIG. 9 is a plan view of an essential part of a piezoelectric acoustic device in which a circuit board of a conventional example is removed.

FIG. 10 is a vertical cross-sectional view taken along the line AA of FIG. 1 with a circuit board of a conventional example of the same piezoelectric acoustic device attached.

[Explanation of symbols]

 21 Vibration Plate 22 Piezoelectric Body 23 Electrode 2 Piezoelectric Element 1 Case 31 Housing 34 Fixing Protrusion 41 Engagement Part 35 Elastic Member 36 Circuit Board 15 Extraction Electrode 12 Connection Block 16 Conductor Part of Connection Block 49 Terminal

Claims (9)

[Utility model registration claims] 1. A piezoelectric element (2) having a piezoelectric body (22) fixed to the main surface of a metal plate-shaped vibrating plate (21), and an electrode (23) provided on the surface of the piezoelectric body (22), A piezoelectric acoustic component including a case (1) in which the piezoelectric element (2) is housed and which forms a resonance chamber, in the outer periphery of the case (1),
Jaw-shaped engaging part (41) with which the tip of a fixing projection (34) having a hook-like tip side surface projecting from the inner surface of a housing (31) of a device to which this case (1) is to be attached engages
A piezoelectric acoustic component characterized by being provided with. 2. The piezoelectric acoustic device according to claim 1, wherein the engagement portion (41) is formed of a projecting step portion provided over the entire circumference or a part of the circumference of the case (1). parts. 3. The piezoelectric acoustic component according to claim 1, wherein the engagement portion (41) is formed of a concave step portion provided over the entire circumference or a part of the circumference of the case (1). . 4. A piezoelectric element (2) in which a piezoelectric body (22) is fixed to the main surface of a diaphragm (21) in the form of a metal plate, and an electrode (23) is provided on the surface of this piezoelectric body (22). A piezoelectric acoustic device in which a piezoelectric acoustic component including the piezoelectric element (2) and a case (1) that forms a resonance chamber together with the piezoelectric element (22) is mounted inside a housing (31) of a device, The piezoelectric acoustic component according to any one of claims 1 to 3 is used, and a jaw-shaped engaging portion (41) provided on the outer circumference of the case (1) is provided with a protrusion on the inner surface of a housing (31) of a device. The case (1) is attached to the housing (3) by engaging the tips of the fixing protrusions (34) whose side surfaces are hook-shaped.
A piezoelectric acoustic device, which is attached to 1). 5. The piezoelectric acoustic device according to claim 4, wherein an elastic member 35 is compressed and sandwiched between the case 1 and the housing 31. 6. A diaphragm (21) for the piezoelectric element (2).
And an extraction electrode (15) extracted from the electrode (23) on the surface of the piezoelectric body (22) to the diaphragm (21) in an insulating state are provided on the elastic connection block (12). The conductor pattern (16), (16) ... is connected to the circuit pattern of the circuit board (36) mounted in the housing (31), respectively, The said, It is characterized by the above-mentioned. Piezoelectric sound device. 7. The connection block (12) comprises a housing (3).
1) A circuit board (36) mounted inside and a piezoelectric element (2)
The piezoelectric acoustic device according to claim 6, wherein the piezoelectric acoustic device is sandwiched between and in a state where a compressive stress is applied. 8. A diaphragm (21) of the piezoelectric element (2) and an electrode (23) on the surface of the piezoelectric body (22) are connected to leaf spring terminals (38), (38), This terminal (3
8. The electrical connection is made by contacting the circuit patterns of the circuit board (36) mounted in the housing (31) with the tips of the parts (8) and (38), respectively. The piezoelectric acoustic device according to. 9. A leaf spring-shaped terminal (38), (38) in a state in which flexural stress is applied between the piezoelectric element (2) and the circuit board (36) mounted in the housing (31). The piezoelectric acoustic device according to claim 8, wherein the piezoelectric acoustic device is sandwiched.