WO2006009279A1

WO2006009279A1 - Piezoelectric sound producing unit

Info

Publication number: WO2006009279A1
Application number: PCT/JP2005/013570
Authority: WO
Inventors: Shozo Nishiyama
Original assignee: Hokuriku Electric Industry Co., Ltd.
Priority date: 2004-07-23
Filing date: 2005-07-25
Publication date: 2006-01-26
Also published as: CN101027937A; JPWO2006009279A1; KR20070048735A; CN101027937B; KR101145231B1; JP4729496B2

Abstract

A piezoelectric sound producing unit capable of enlarging the amplitude of the diaphragm of a piezoelectric vibrator. The front surface-side outer peripheral surface (17c) of a diaphragm (17) and a support (1) are joined together by a joining means. The joining means is formed of a flexible synthetic resin sheet (9), and is arranged across the front surface-side outer peripheral surface (17c) of the diaphragm (17) and the support portion (5) of the support (1) so as to allow the diaphragm (17) to vibrate as a whole. The electric insulating layer (25) of a first lead-out means (23) for electrically connecting the first electrode (19a) of a first piezoelectric element (19) with a first output electrode (13a) and a first lead-out conductor (27) are formed of thick films coated with insulating resin paste. The electric insulating layer (31) of a second lead-out means (29) for electrically connecting the first electrode (21a) of a second piezoelectric element (21) with a first output electrode (13) and a second lead-out conductor (33) are formed of thick films coated with insulating resin paste. The electrically-insulating layer and the connecting conductor of a connecting means for connecting electrically the diaphragm (17) and a second output electrode (15) together are also formed of thick films coated with insulating resin paste.

Description

Specification

Piezoelectric sounder

Technical field

[0001] The present invention relates to a piezoelectric sound generator.

Background art

[0002] Japanese Unexamined Patent Publication No. 2003-78995 (Patent Document 1) discloses a thin piezoelectric sounding device in which a piezoelectric vibrating body is supported by a support body having an annular support portion. The piezoelectric vibrator is configured by joining the first and second piezoelectric elements so as to leave the periphery of the diaphragm on both surfaces of a metal diaphragm. And the peripheral part of the single side | surface of a diaphragm is joined to the cyclic | annular support part using the adhesive agent. In this piezoelectric sounder, a metal foil is disposed between the surface electrodes of the first and second piezoelectric elements and the terminal portion in a state of being insulated from the diaphragm, and the metal foil is bonded with conductivity. It is joined by the agent. Then, the metal foil and the surrounding piezoelectric element are covered with a reinforcing member such as a synthetic resin tape, and a conductive portion is provided between the surface electrode and the output electrode of the first and second piezoelectric elements. Having a bow I forming means. Patent Document 1: Japanese Patent Laid-Open No. 2003-78995

Disclosure of the invention

Problems to be solved by the invention

[0003] The above-described thin piezoelectric sounder has a problem that the amplitude of the diaphragm cannot be increased because the diameter of the diaphragm is small. In addition, compared with the case where the lead wire is soldered to the surface electrode of the first and second piezoelectric elements, the surface electrode and the terminal portion of the first and second piezoelectric elements are not increased by the amount of solder. The thickness dimension of the conductive part connecting the gaps can be reduced. However, with this structure, the thickness dimension of the conductive portion cannot be further reduced. Further, in this conventional piezoelectric sound generator, since the bonding strength of the metal foil is low, it is necessary to cover the metal foil with a reinforcing member such as a synthetic resin tape so that the metal foil does not peel off. There is a problem that the number of manufacturing steps increases as the number of items increases.

An object of the present invention is to provide a piezoelectric sounder capable of increasing the amplitude of a diaphragm of a piezoelectric vibrating body. Another object of the present invention is to provide a piezoelectric sounder that is thinner than the conventional one.

[0006] Still another object of the present invention is to provide a piezoelectric sounder having a simpler structure and higher reliability than conventional ones.

[0007] Another object of the present invention is to provide a piezoelectric sounder capable of reducing the thickness dimension of the first and second lead means for connecting between the first and second piezoelectric elements and the output electrode. is there.

[0008] Another object of the present invention is to provide a piezoelectric sounder capable of increasing the bonding strength of the first and second extraction means.

Means for solving the problem

[0009] A piezoelectric sounder to be improved by the present invention includes a piezoelectric vibrating body in which a piezoelectric element is joined to a diaphragm so as to leave an annular outer peripheral surface portion, and a support body that supports the outer peripheral portion of the diaphragm. And a connecting means for connecting the outer peripheral portion of the vibration plate and the support. In the present invention, the connecting means is formed of a synthetic resin sheet having flexibility, and is arranged across the outer peripheral surface portion and the support portion of the diaphragm so that the diaphragm can vibrate as a whole. According to the present invention, the diaphragm is supported by the support via the flexible synthetic resin sheet (connecting means) that prevents the outer peripheral portion of the diaphragm from contacting the support. Therefore, the diaphragm can vibrate as a whole and the amplitude of the diaphragm can be increased. As a result, the resonance frequency of the diaphragm can be lowered and the volume can be increased.

[0010] When the piezoelectric element is configured to have the first electrode on the front surface and the second electrode on the back surface, the second electrode may be bonded to the diaphragm. In this case, the synthetic resin sheet is integrally provided with an extension extending on the first electrode beyond the outer peripheral surface portion of the vibrator, and the first resin connected to the first electrode is provided on the synthetic resin sheet. It is preferable to provide a wiring pattern and a second wiring pattern connected to the diaphragm, and extend the first wiring pattern on the extension portion of the synthetic resin sheet. In this way, the first electrode of the piezoelectric element can be connected to the output electrode using the first wiring pattern, for example, by soldering both ends of the first wiring pattern. Then, by soldering the both ends of the second wiring pattern, the diaphragm of the piezoelectric element and the output electrode can be connected using the second wiring pattern. Therefore, the connection between the piezoelectric element and the output electrode can be facilitated, and the number of parts related to the connection between both can be reduced. The piezoelectric sounder of the present invention can be applied to a double-morph type in which a piezoelectric element is bonded to only one surface of a diaphragm, or a bimorph type in which a piezoelectric element is bonded to both of the diaphragms. It can also be applied to

A specific piezoelectric sounder of the present invention includes a piezoelectric vibrator, a support having an annular support portion, a coupling means, a drawing means, and a connection means. The piezoelectric vibrator has a metal diaphragm having a front surface and a back surface, a first electrode on the front surface and a second electrode on the back surface, and leaves a front outer peripheral surface portion of the surface of the vibration plate. The second electrode is joined to the surface of the diaphragm so as to be electrically conductive. The connecting means is formed of an electrically insulating material and connects the outer peripheral surface portion of the vibration plate and the support portion. The lead-out means has a lead-out conductive part electrically connected to the first electrode of the piezoelectric element. The connecting means has a connecting conductive portion electrically connected to the vibration plate of the piezoelectric element. Then, the coupling means is formed of a flexible synthetic resin sheet, and is disposed across the outer peripheral surface portion and the support portion of the diaphragm so that the diaphragm can vibrate as a whole. The lead-out means has an electrically insulating layer formed of a thick film or a thin film so as to straddle the first electrode of the piezoelectric element, the outer peripheral surface portion on the surface side, and the connecting means. The lead conductive part is formed of a thick film or a thin film so that the tip part is connected to the first electrode of the first piezoelectric element and at least a part of the remaining part is located on the electrically insulating layer. Consists of a conductive layer!

According to this configuration, since the electrically insulating layer of the extraction means and the conductive portion for extraction are formed of a thick film or a thin film, the thickness dimension of the extraction means extracted from the first electrode of the piezoelectric element is compared with the conventional one. Can be small. Further, since the joining strength of the drawing means can be increased as compared with the conventional case, it is possible to provide a highly reliable piezoelectric sounder without using a reinforcing member as in the conventional case.

[0014] When a bimorph type piezoelectric element is employed, the piezoelectric element is composed of a first piezoelectric element and a second piezoelectric element that are bonded to both surfaces of the diaphragm. The first piezoelectric element has a first electrode on the front surface and a second electrode on the back surface, and the second electrode is placed on the surface of the diaphragm so as to leave the outer peripheral surface of the front surface side of the diaphragm. It is joined so as to be electrically conductive. The second piezoelectric element has a first electrode on the front surface and a second electrode on the back surface, and the second electrode is electrically connected to the back surface of the vibration plate so as to leave the outer peripheral surface of the back surface of the vibration plate. Lead to It is joined so that it can pass. In this case, the first lead means having the first lead conductive portion electrically connected to the first electrode of the first piezoelectric element and the first electrode of the second piezoelectric element are electrically connected. And a second drawing means having a second drawing conductive portion.

According to this configuration, the first and second piezoelectric elements are formed by forming the respective electrically insulating layers and the drawing conductive portions of the first drawing means and the second drawing means with a thick film or a thin film. The thickness dimension of the first extraction means and the second extraction means extracted from each first electrode of the child can be reduced as compared with the conventional case. In addition, since the bonding strength of the first drawing means and the second drawing means can be increased as compared with the prior art, it is possible to provide a highly reliable piezoelectric speaker that does not use a reinforcing member as in the prior art.

[0016] If the connecting means is disposed so as to cover the outer peripheral surface portion of the surface side of the diaphragm, the outer peripheral surface portion of the front surface side is not exposed, and therefore a step is formed in the region where the electrically insulating layer of the first extraction means is formed. Thus, the electrical insulating layer can be easily formed flat. In such a case, it is only necessary to form an electrically insulating layer so as to straddle the first electrode of the first piezoelectric element and the connecting means.

[0017] Although the configuration of the support is arbitrary, the first output electrode to which the first and second lead conductive portions are electrically connected and the second output electrode to which the diaphragm is electrically connected The support body may be configured to have an output electrode holding portion including In this case, the front surface side outer peripheral surface portion or the rear surface side outer peripheral surface portion of the vibration plate and the second output electrode are electrically connected by the connecting means having the connecting conductive portion. This connecting means is composed of an electrically insulating layer and a conductive part for connection. The electrical insulating layer can be formed of a thick film or a thin film so as to straddle the outer peripheral surface portion or the rear outer peripheral surface portion of the diaphragm and the connecting means. The leading end of the connecting conductive portion is connected to the outer peripheral surface portion or the outer peripheral surface portion on the front surface side, the rear end portion is connected to the second output electrode, and the remaining portion is positioned on the electrically insulating layer. In addition, the conductive layer may be formed of a thick film or a thin film. If the electrical insulating layer of the connection means and the conductive portion for connection are formed of a thick film or a thin film in this way, the thickness of the connection means between the diaphragm and the second output electrode can be made smaller than before. . Further, the bonding strength between the diaphragm and the connecting means can be increased as compared with the conventional case.

[0018] The first output electrode is formed adjacent to a surface portion to which the connecting means of the support portion is connected. And an output electrode extension extending to the surface portion and the inner peripheral surface portion of the support portion, and electrically connecting the conductive layer constituting the second lead conductive portion to the output electrode extension. preferable. In this way, by using the output electrode extension that extends to the inner peripheral surface portion of the support portion, the first lead conductive portion, the second lead conductive portion, and the first output electrode can be easily connected. It can be electrically connected by the structure.

[0019] The output electrode extension is configured to extend to the back surface portion facing the front surface portion of the support portion in the thickness direction, and the second output electrode is at least the front surface portion, the inner peripheral surface portion, and the back surface of the support portion. It is preferable to form so as to straddle the surface portion. In this way, since the first and second output electrodes can be present on both the front and back portions of the support portion, there is an advantage that the piezoelectric sound generator can be easily mounted on the circuit board. It is done.

[0020] An electrode in which the second lead conductive portion is disposed on the back side of the diaphragm, and the conductive layer of the second lead conductive portion is formed on the inner peripheral surface portion of the support portion of the first output electrode If it is electrically connected to the portion, the second lead conductive portion and the first output electrode can be easily electrically connected.

[0021] The support can be constituted by a substrate formed of an electrically insulating material and having a substantially equal thickness. If the support is configured using the substrate in this way, the support can be mass-produced by punching the substrate, and the first and second output electrodes can be formed using a known circuit pattern forming technique. Therefore, the cost of the support can be lowered than before.

[0022] It is preferable that the connecting means is composed of a flexible synthetic resin sheet having an annular portion bonded to the surface of the support portion of the support via an adhesive layer. In this case, the piezoelectric vibrating body is supported on the support portion by the connecting means so that the vibration plate does not contact the inner peripheral surface of the support portion and the vibration plate and the second piezoelectric element are accommodated inside the support portion. It is preferable to do. In this way, the movement of the outer peripheral portion of the diaphragm is not substantially restrained, so that the amplitude of the diaphragm can be maximized.

[0023] When the connecting means is composed of a synthetic resin sheet, it is preferable to further provide an annular protective layer fixed on the synthetic resin sheet so that the synthetic resin sheet is sandwiched between the supporting portion and the support portion. If it does in this way, a synthetic resin sheet will peel from a support part by a protective layer. Can be prevented. In this case, the thickness dimension of the protective layer is determined so that the first piezoelectric element of the piezoelectric vibrator and the first lead conductive portion can be completely accommodated in the space surrounded by the protective layer. Is preferred. In this way, the first piezoelectric element and the first lead-out conductive portion of the piezoelectric vibrating body can be transported or automatically mounted on a circuit board or the like by an automatic mounting machine due to the presence of the protective layer. It is possible to prevent other parts from coming into contact with each other, thereby reducing the defect rate of products using piezoelectric sound generators. This protective layer can be composed of, for example, another synthetic resin sheet attached on the synthetic resin sheet via an adhesive layer. If it does in this way, a protective layer can be arrange | positioned easily.

[0024] The electrically insulating layer used to constitute the first and second extraction means is formed of a thick film formed by applying an insulating resin paste, and the conductive layer is formed of a conductive resin paste. A thick film may be formed by coating. In this way, the electrically insulating layer and the conductive layer can be easily and inexpensively formed using a printing technique.

Brief Description of Drawings

FIG. 1 is a plan view of a piezoelectric sounder according to an embodiment of the present invention.

[FIG. 2] (A) is a back view of the piezoelectric sounder according to the embodiment of the present invention, and (B) is a diagram showing a configuration of an output electrode holding portion.

FIG. 3 is a cross-sectional view taken along the line ΠΙ-ΠΙ in FIG.

4 is a cross-sectional view taken along line IV-IV in FIG.

FIG. 5 is a diagram showing wiring of the piezoelectric sounder shown in FIG. 1.

[FIG. 6] (A) is a schematic diagram showing how the diaphragm of the piezoelectric sounder shown in FIG. 1 vibrates! / Swings, and (B) is the vibration of the piezoelectric sounder of the comparative example. It is the schematic which shows a mode that it is vibrating.

FIG. 7 is a cross-sectional view of a piezoelectric sounder according to another embodiment of the present invention.

FIG. 8 is a plan view of connecting means used in the piezoelectric sounder shown in FIG.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the piezoelectric sounder of the present invention will be described in detail with reference to the drawings. FIGS. 1 and 2A are a plan view and a bottom view of the piezoelectric sounder according to the first embodiment of the present invention, and FIG. 3 is a cross-sectional view taken along the line ΠΙ-ΠΙ in FIG. Is a cross-sectional view taken along line IV-IV in Fig. 1. It is a figure which shows the wiring of the piezoelectric sounder of this Embodiment. To facilitate understanding

3 and FIG. 4, the thickness dimension of a part is exaggerated. As shown in each drawing, the piezoelectric sounding device of the present embodiment has a support 1 and a piezoelectric vibrating body 3 supported by the support 1. The support body 1 has a support portion 5 and an output electrode holding portion 7 integrally, and is formed by stamping a substrate formed of an electrically insulating material, such as a glass epoxy resin substrate, with a substantially equal thickness. It is formed by. The support portion 5 has an annular shape. As shown in FIG. 2 (B), the inner peripheral portion of the portion connected to the output electrode holding portion 7 has two cross-sectional shapes that form a semicircular arc shape. Recesses 5a and 5b are formed. The output electrode holding portion 7 includes an electrode portion that is continuous with the front surface regions 5c and 5d and the back surface regions 5e and 5f connected to the two recesses 5a and 5b. The front side regions 5c and 5d and the back side regions 5e and 5f are provided with first and second copper foils that are part of the first and second output electrode constituent parts 13 and 15 and that are made of gold-plated copper foil. Second output electrodes 13a and 15a and first and second backside electrodes 13b and 15b are formed. As shown in FIG. 3 and FIG. 4, conductive connecting portions 13c and 15c are formed on the inner surfaces of the two recesses 5a and 5b by a conductive thin film such as plating. The support portion 5 has a thickness dimension in which a later-described diaphragm 17, a second piezoelectric element 21, and a second lead conductive portion 29 of the piezoelectric vibrator 3 are completely accommodated.

[0027] Further, a synthetic resin sheet 9 constituting a connecting means is bonded to the surface 5g of the support portion 5 via an adhesive layer (not shown). The synthetic resin sheet 9 is flexible and has an annular polyester tape force having an adhesive on one side. This synthetic resin sheet 9 has an annular portion 9a joined to the support portion 5 and a vibrator joint portion 9b to which the piezoelectric vibrator 3 is joined on the inner peripheral side of the annular portion 9a. A protective layer 11 is fixed to the surface 5g of the support portion 5 via an adhesive layer (not shown) so that the annular portion 9a of the synthetic resin sheet 9 is sandwiched between the support portion 5 and the annular portion 9a. The protective layer 11 has an annular shape made of polyester having an adhesive on one side, and is disposed so as to straddle over a first lead conductive portion 23 described later, as shown in FIG. The protective layer 11 has a thickness dimension in which a first piezoelectric element 19 and a first lead-out conductive portion 23 (to be described later) of the piezoelectric vibrating body 3 are completely accommodated.

[0028] The output electrode holding portion 7 has a shape close to a rectangular parallelepiped, and is radially outward from the support portion 5. It is formed to extend. As described above, the output electrode holding portion 7 includes the first output electrode constituting portion 13 and the second output electrode constituting portion 15 which are formed side by side. The first output electrode constituting portion 13 includes a first output electrode 13a formed adjacent to the surface portion to which the synthetic resin sheet (connecting means) 9 of the support portion 5 is connected, An output electrode extension (conductive connection portion 13c and first backside electrode 13b) extending to the peripheral surface portion (groove 5a) is provided. The output electrode extension extends to the back surface portion facing the front surface portion of the support portion 5 in the thickness direction. Similarly to the first output electrode component 13, the second output electrode component 15 is also formed adjacent to the surface portion to which the synthetic resin sheet (connection means) 9 of the support 5 is connected. An output electrode 15a and an output electrode extension (conductive connection portion 15c and second backside electrode 15b) extending to the surface portion and the inner peripheral surface portion of the support portion 5 are provided. That is, the first output electrode component 13 and the second output electrode component 15 are both formed so as to straddle the front surface portion, the inner peripheral surface portions (grooves 5a, 5b), and the back surface portion of the support portion 5. !

The piezoelectric vibrating body 3 includes a diaphragm 17, a first piezoelectric element 19, and a second piezoelectric element 21. That is, in this example, a bimorph type piezoelectric element in which the piezoelectric elements 19 and 21 are joined to both of the diaphragms 17 is employed. The diaphragm 17 has a disc shape having a front surface 17a and a back surface 17b, and is formed of a metal plate having an iron-nickel alloy force. The first piezoelectric element 19 is a laminated piezoelectric element having a structure in which a plurality of piezoelectric ceramic layers and electrode layers are alternately laminated so as to have a first electrode 19a on the front surface and a second electrode 19b on the back surface. is there. In the first piezoelectric element 19, the second electrode 19 b is joined to the surface 17 a of the diaphragm 17 so as to be electrically conductive so as to leave the outer peripheral surface portion 17 c of the surface 17 a of the diaphragm 17. Similarly to the first piezoelectric element 19, the second piezoelectric element 21 has a plurality of piezoelectric ceramic layers and electrode layers alternately laminated so that the first electrode 21a is provided on the front surface and the second electrode 21b is provided on the back surface. A laminated piezoelectric element having the above structure. In the second piezoelectric element 21, the second electrode 2 lb is joined to the back surface 17 b of the diaphragm 17 so as to be electrically conductive so as to leave the outer peripheral surface portion 17 d of the back surface 17 b of the diaphragm 17. . The annular surface-side outer peripheral surface portion 17c of the surface 17a of the diaphragm 17 is joined to the surface adjacent to the support portion 5 of the vibration member joining portion 9b of the synthetic resin sheet (connecting means) 9 described above. As a result, the outer peripheral surface portion 17c on the surface side of the diaphragm 17 and the support body 1 are connected by the synthetic resin sheet 9, and the piezoelectric vibration body 3 is The front surface 17 a and the back surface 17 b of the moving plate 17 are supported by the support portion 5 by the synthetic resin sheet 9 without contacting the support portion 5. In other words, the synthetic resin sheet (connecting means) 9 is disposed across the outer peripheral surface portion 17c and the support portion 5 of the diaphragm 17 so that the diaphragm 17 can vibrate as a whole. The diaphragm 17 and the second piezoelectric element 21 are housed inside the support portion 5.

[0030] The first electrode 19a of the first piezoelectric element 19 and the first output electrode 13 are electrically connected by a first extraction means 23. The first lead means 23 includes an electrical insulation layer 25 and a first lead conductive part 27 formed on the electrical insulation layer 25. As shown in FIG. 3, the electrical insulating layer 25 is a thick insulating film formed by applying an insulating resin paste made of acrylic urethane resin. The electrical insulating layer 25 extends over the first electrode 19a of the first piezoelectric element 19, the outer peripheral surface portion 17c on the surface side of the diaphragm 17, and the synthetic resin sheet 9 so as to be near the center of the first electrode 19a. It extends between the first output electrode 13a. The first lead conductive portion 27 is a thick conductive film formed by applying a conductive resin paste having the same strength as that of a resin-silver paste. The first lead conductive portion 27 has a tip portion 27a connected to the first electrode 19a of the first piezoelectric element 19 in the vicinity of the center of the first electrode 19a, and a rear end portion 27b connected to the first output electrode. Connected to 13a. The remainder is located on the electrical insulating layer 25.

The first electrode 21 a of the second piezoelectric element 21 and the first output electrode 13 are electrically connected by the second extraction means 29. The second lead means 29 includes an electrically insulating layer 31 and a second bow I extending conductive portion 33 formed on the electrically insulating layer 31. The electrical insulating layer 31 is formed of a thick film coated with an insulating resin paste made of acrylic urethane resin. The electrical insulating layer 31 is electrically connected to the vicinity of the center of the second electrode 21a so as to straddle the first electrode 21a of the second piezoelectric element 21, the outer peripheral surface portion 17d on the back surface side of the diaphragm 17, and the synthetic resin sheet 9. It extends between the connecting portion 13c. The second lead conductive portion 33 is a thick conductive film formed by applying a conductive resin paste such as resin-silver paste. The second lead conductive portion 33 has a tip 33a connected to the first electrode 21a of the second piezoelectric element 21 in the vicinity of the center of the second electrode 21a, and a rear end 33b on the groove 5a. Connected to the conductive connection portion 13c of the output electrode extension portion of the first output electrode configuration portion 13. And The remainder is located on the electrically insulating layer 31. Thus, as shown in FIG. 5, the first lead conductive portion 27, the second lead conductive portion 33, and the first output electrode 13 are electrically connected.

[0032] The diaphragm 17 and the second output electrode 15 are electrically connected by the connecting means 35. The o connecting means 35 is for connection formed on the electrically insulating layer 37 and the electrically insulating layer. conductive portion ³ and a 9. The electrically insulating layer 37 is formed of a thick film coated with an insulating resin paste made of acrylic urethane resin. The electrical insulating layer 37 is formed so as to straddle the back surface side outer peripheral surface portion 17d of the diaphragm 17 and the synthetic resin sheet 9. The connecting conductive portion 39 is a thick conductive film formed by applying a conductive resin paste such as resin-silver paste. The conductive portion 39 for connection is connected to the conductive connection portion 15c of the output electrode extension portion of the second output electrode constituting portion 15 at the front end portion 39a thereof on the back side outer peripheral surface portion 17d and the rear end portion 39b on the groove 5b. It is connected. The remainder is located on the electrical insulating layer 37.

[0033] Fig. 6 (A) is a schematic view showing a state in which the diaphragm 17 of the piezoelectric sounder of this example vibrates, and Fig. 6 (B) shows an adhesive applied to the surface of the support R5. FIG. 6 is a schematic view showing a state where a diaphragm R17 of a piezoelectric sound generator of a comparative example (for example, Japanese Patent Application Laid-Open No. 2003-78995) in which a diaphragm R17 is connected via is vibrating. From both figures, the amplitude f of the piezoelectric speaker of this example shown in FIG. 6 (A) is the amplitude f of the piezoelectric speaker of the comparative example shown in FIG. 6 (B).

It can be seen that it is larger than 2. This is because in the piezoelectric sounder of this example, the front surface 17a and the rear surface 17b of the diaphragm 17 of the piezoelectric vibrating body 3 are supported by the support portion 5 via the connecting means 9 without contacting the support portion 5. It is.

In the piezoelectric sounder of this example, the electrical insulating layer 25 and the first lead conductive portion 27 of the first lead means 23 and the electrical insulating layer 31 and the second lead means 29 of the second lead means 29 are also used. Since the lead conductive portion 33 is formed of a thick film, the conductive portion between the first electrodes 19a, 21a of the first and second piezoelectric elements 19, 21 and the first output electrode 13 ( The thickness dimensions of the first drawing means 23 and the second drawing means 29) can be made smaller than before. In addition, the bonding strength between the first electrodes 19a and 21a of the first and second piezoelectric elements 19 and 21 and the conductive portion (the first extraction means 23 and the second extraction means 29) can be increased as compared with the related art.

FIG. 7 is a sectional view of a piezoelectric sounder according to another embodiment (second embodiment) of the present invention. is there. The piezoelectric sounder of this example uses a morph type piezoelectric element in which the piezoelectric element 119 is joined only to one surface 117 a of the diaphragm 117. Further, as the connecting means, as shown in FIG. 8, a structure in which a first wiring pattern 151 and a second wiring pattern 153 are provided on a synthetic resin sheet 109 is used. The synthetic resin sheet 109 is made of polyimide used for a flexible substrate or the like, and has an annular portion 109a, an electrode formation portion 109b, and an extension portion 109c. The electrode forming portion 109b has a substantially rectangular shape and is formed so as to extend radially outward from the annular portion 109a. The extension portion 109c is formed at a position facing a part of the electrode forming portion 109b via the annular portion 109a, and extends inside the annular portion 109a.

[0036] The first wiring pattern 151 is made of copper foil and extends over the electrode forming portion 109b, the annular portion 109a, and the extension portion 109c. The tip portion 151a of the first wiring pattern 151 is electrically joined to the first electrode 119a of the piezoelectric element 119 via the thick film portion 155 formed using a conductive paste. The rear end portion 15 lb of the first wiring pattern 151 is electrically connected to the first output electrode 113a through the thick portion ₁₅ 7 formed by using a conductive paste.

[0037] The second wiring pattern 153 is made of a copper foil and extends in parallel with the first wiring pattern 151 over the electrode forming portion 109b and the annular portion 109a. The tip portion 153a of the second wiring pattern 153 is electrically joined to the surface 117a of the diaphragm 117 of the piezoelectric element 119 via a thick film portion formed using a conductive paste. The rear end portion 153b of the second wiring pattern 153 is electrically joined to the second output electrode through a thick film portion formed using a conductive paste.

In the piezoelectric sounder of this example, the first wiring pattern 151 can be used to connect the first electrode 119a and the first output electrode 113a of the piezoelectric element 119, and the second wiring pattern 15 3 can be used to connect the diaphragm 117 of the piezoelectric element 119 to the second output electrode. Therefore, the connection between the piezoelectric element 119 and each output electrode can be facilitated, and the number of parts related to the connection between both can be reduced.

In the above embodiment, the connection between the first and second wiring patterns 151 and 153 and the respective parts is performed by the thick film part formed using the conductive paste. You may connect the part. Further, a through hole is formed in a portion of the synthetic resin sheet 109 where the first wiring pattern 151 or the second wiring pattern 153 is located, and a through hole conductive portion is formed in the through hole using a conductive paste or the like. In addition, the first wiring pattern 151 or the second wiring pattern 153 can be connected to a predetermined portion.

In each of the above embodiments, the electrically insulating layer, the lead conductive portion, and the connection conductive portion are formed of a thick film. However, the electrical insulating layer and the lead are formed using a technique such as sputtering or vapor deposition. Of course, the conductive part and the conductive part for connection may be formed of a thin film. Moreover, it can also form with metal foil, such as copper foil.

[0041] In the first embodiment, a bimorph type piezoelectric element is used. In the second embodiment, a double-morph type piezoelectric element is used. However, the present invention is not limited to any type. In the first embodiment, a morph type piezoelectric element may be employed, and in the second embodiment, a bimorph type piezoelectric element may be employed.

[0042] In each of the above embodiments, the support 1 is formed using an insulating material made of glass-epoxy resin, but the support may be formed using a conductive material such as a metal. I do not care. In this case, an insulating layer may be formed on the surface of the conductive material, and an output electrode may be formed on this insulating layer.

Industrial applicability

[0043] According to the present invention, the diaphragm is supported by the support body via the connecting means whose outer peripheral portion does not contact the support portion. Therefore, the diaphragm can vibrate as a whole, and the amplitude of the diaphragm can be increased. As a result, the resonance frequency of the diaphragm can be lowered and the volume can be increased.

[0044] Further, since the electrically insulating layer and the lead conductive portion of the lead-out means are formed of a thick film or a thin film, the thickness dimension of the lead-out means drawn out from the first electrode of the piezoelectric element can be reduced as compared with the conventional case. . Further, since the joining strength of the drawing means can be increased as compared with the conventional case, it is possible to provide a highly reliable piezoelectric sounding device without using a reinforcing member as in the conventional case.

Claims

The scope of the claims

A metal diaphragm having a front surface and a back surface;

The first electrode on the front surface and the second electrode on the back surface, and the second electrode is electrically connected to the surface of the diaphragm so as to leave the outer peripheral surface portion of the front surface of the diaphragm. A first piezoelectric element joined in a conductive manner;

The first electrode on the front surface and the second electrode on the back surface, and the second electrode is electrically connected to the back surface of the diaphragm so as to leave the outer peripheral surface portion on the back surface side of the back surface of the diaphragm. A piezoelectric vibrator comprising a second piezoelectric element joined so as to be conductive;

A support having an annular support;

A connecting means that is formed of an electrically insulating material and connects the outer peripheral surface portion of the surface side of the diaphragm and the support portion;

First extraction means having a first extraction conductive portion electrically connected to the first electrode of the first piezoelectric element;

A piezoelectric sounder comprising: a second lead means having a second lead conductive portion electrically connected to the first electrode of the second piezoelectric element;

The connecting means is formed of a flexible synthetic resin sheet, and is disposed across the outer peripheral surface portion and the support portion of the diaphragm so that the diaphragm can vibrate as a whole.

The first lead means has an electrically insulating layer formed of a thick film or a thin film so as to straddle the first electrode of the first piezoelectric element, the outer peripheral surface portion of the surface side, and the connecting means. The first lead conductive portion has a thickness such that a tip portion thereof is connected to the first electrode of the first piezoelectric element and at least a part of the remaining portion is located on the electrically insulating layer. Consists of a conductive layer formed by a film or thin film,

The second extraction means includes an electrical insulating layer formed of a thick film or a thin film so as to straddle the first electrode of the second piezoelectric element and the outer peripheral surface portion on the back surface side. The leading conductive portion of the second lead is connected to the first electrode of the second piezoelectric element, and at least a part of the remaining portion is positioned on the electrically insulating layer. A piezoelectric sounder comprising a conductive layer formed by the method described above.

[2] The support includes: a first output electrode to which the first and second lead conductive portions are electrically connected; and a second output electrode to which the diaphragm is electrically connected. An output electrode holding portion provided integrally with the support portion;

The front surface side outer peripheral surface portion or the back surface side outer peripheral surface portion of the diaphragm and the second output electrode are electrically connected by a connection means having a conductive part for connection, and the connection means is connected to the diaphragm. An electrical insulating layer formed of a thick film or a thin film so as to straddle the surface-side outer peripheral surface portion or the back-surface-side outer peripheral surface portion and the connecting means, and the leading end portion of the connecting conductive portion A conductive film formed of a thick film or a thin film so as to be connected to the outer peripheral surface portion or the outer peripheral surface portion on the back surface side, the rear end portion being connected to the second output electrode, and the remaining portion being positioned on the electrical insulating layer. 2. The piezoelectric sounder according to claim 1, wherein the piezoelectric sounder is formed by layers!

[3] The first output electrode is formed adjacent to a surface portion to which the connecting means of the support portion is connected and extends to the surface portion and the inner peripheral surface portion of the support portion. With

3. The piezoelectric sounding device according to claim 2, wherein the conductive layer constituting the second lead conductive portion is electrically connected to the output electrode extension portion.

[4] The output electrode extension extends to the back surface portion facing the front surface portion of the support portion in the thickness direction,

4. The piezoelectric sounder according to claim 3, wherein the second output electrode is formed so as to straddle at least the surface portion, the inner peripheral surface portion, and the back surface portion of the support portion.

[5] The second lead conductive portion is disposed on the back side of the diaphragm, and the conductive layer of the second lead conductive portion is the inner portion of the support portion of the first output electrode. The piezoelectric sounder according to claim 1, wherein the piezoelectric sounder is electrically connected to an electrode portion formed on the peripheral surface portion.

[6] The support is constituted by a substrate formed of an electrically insulating material and having substantially the same thickness.

The connecting means is composed of a flexible synthetic resin sheet having an annular portion bonded to the surface of the support portion of the support through an adhesive layer, The piezo-electric vibrator is coupled by the coupling means so that the diaphragm does not come into contact with the inner peripheral surface of the support part and the diaphragm and the second piezoelectric element are accommodated in the support part. The piezoelectric sounding device according to claim 1, wherein the piezoelectric sounding device is supported with respect to the supporting portion.

[7] It further includes an annular protective layer fixed on the synthetic resin sheet so as to sandwich the synthetic resin sheet between the support portion and

2. The piezoelectric sounding device according to claim 1, wherein the protective layer has a thickness dimension in which the first piezoelectric element and the first lead-out conductive portion of the piezoelectric vibrator are completely accommodated.

8. The piezoelectric sounding device according to claim 7, wherein the protective layer is made of another synthetic resin sheet attached on the synthetic resin sheet via an adhesive layer.

[9] The electrical insulating layer is a thick film formed by applying an insulating resin paste, and the conductive layer is a thick film formed by applying a conductive resin paste. Claims

The piezoelectric sound generator according to 1.

[10] a metal diaphragm having a front surface and a back surface;

The first electrode on the front surface and the second electrode on the back surface, and the second electrode is electrically connected to the surface of the diaphragm so as to leave the outer peripheral surface portion of the front surface of the diaphragm. A piezoelectric vibrator comprising a piezoelectric element joined in a conductive manner;

A support having an annular support;

An extraction means having an extraction conductive portion electrically connected to the first electrode of the piezoelectric element;

A piezoelectric sounder comprising a connecting means having a connecting conductive portion electrically connected to the diaphragm of the piezoelectric element;

The lead-out means has an electrical insulating layer formed of a thick film or a thin film so as to straddle the first electrode of the piezoelectric element, the surface-side outer peripheral surface portion, and the connecting means, The leading conductive portion is made of a thick film or a thin film so that a tip portion thereof is connected to the first electrode of the first piezoelectric element and at least a part of the remaining portion is located on the electrically insulating layer. A piezoelectric sounder characterized by comprising a conductive layer formed.

[11] a metal diaphragm having a front surface and a back surface;

A support having an annular support;

Connecting means for connecting the surface-side outer peripheral surface portion and the support portion so as to cover the surface-side outer peripheral surface portion of the diaphragm and formed of an electrically insulating material;

The first extraction means has an electrically insulating layer formed of a thick film or a thin film so as to straddle the first electrode of the first piezoelectric element and the connection means, and the first extraction means The conductive portion is formed by a thick film or a thin film so that a tip portion thereof is connected to the first electrode of the first piezoelectric element and at least a part of the remaining portion is located on the electrically insulating layer. Composed of conductive layers,

[12] a piezoelectric vibrating body in which a piezoelectric element is bonded to the diaphragm so as to leave an annular outer peripheral surface portion; A support that supports the outer periphery of the diaphragm;

A piezoelectric sounder comprising a connecting means for connecting the outer peripheral portion of the diaphragm and the support,

The connecting means is formed of a flexible synthetic resin sheet, and is disposed across the outer peripheral surface portion and the support portion of the diaphragm so that the diaphragm can vibrate as a whole. A piezoelectric sound generator characterized by

[13] The piezoelectric element has a first electrode on the front surface and a second electrode on the back surface,

The second electrode is bonded to the diaphragm;

The synthetic resin sheet is integrally provided with an extension extending on the first electrode beyond the outer peripheral surface of the vibrating body,

On the synthetic resin sheet, a first wiring pattern connected to the first electrode and a second wiring pattern connected to the diaphragm are provided,

13. The piezoelectric sounder according to claim 12, wherein the first wiring pattern extends on the extension portion of the synthetic resin sheet.

14. The piezoelectric sounder according to claim 12, wherein the piezoelectric element is a unimorph type or bimorph type piezoelectric element.