JP4729496B2 - Piezoelectric sounder - Google Patents

Description

  The present invention relates to a piezoelectric sound generator.

Japanese Patent Laying-Open 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 vibrating body is configured by joining first and second piezoelectric elements so as to leave a peripheral portion 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 sounding device, a metal foil is disposed between the surface electrodes and the terminal portions of the first and second piezoelectric elements in a state of being insulated from the diaphragm, and the metal foil is used as an adhesive having conductivity. Are joined together. Then, the metal foil and the surrounding piezoelectric element portion 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. It forms a withdrawal means.
JP 2003-78995 A

  The above-described thin piezoelectric sounder has a problem that the diameter of the vibration of the diaphragm is small and the amplitude of the diaphragm cannot be increased. Further, as compared with the case where the lead wire is soldered to the surface electrodes of the first and second piezoelectric elements, there is no rise of the solder, so that there is no gap between the surface electrodes of the first and second piezoelectric elements and the terminal portion. It is possible to reduce the thickness dimension of the conductive part connecting the two. 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 further cover the metal foil with a reinforcing member such as a synthetic resin tape so that the metal foil is not peeled off. There was a problem that not only increased, but also the number of manufacturing steps increased.

  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 before.

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

  Another object of the present invention is to provide a piezoelectric sounding device that can reduce the thickness of the first and second lead-out means connecting the first and second piezoelectric elements and the output electrode.

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

  The 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, a support that supports the outer peripheral part of the diaphragm, and a diaphragm And a connecting means for connecting the outer peripheral portion and the support. In the present invention, 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. According to the present invention, the diaphragm is supported on the support via the flexible synthetic resin sheet (connecting means) without the outer peripheral portion of the diaphragm 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.

  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 portion that extends over the first electrode beyond the outer peripheral surface portion of the vibrating body, and the first wiring connected to the first electrode is provided on the synthetic resin sheet. It is preferable to provide a 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, by soldering the both ends of the first wiring pattern, it is possible to connect the first electrode and the output electrode of the piezoelectric element using the first wiring pattern. By soldering both ends of the second wiring pattern, it is possible to connect the diaphragm of the piezoelectric element and the output electrode 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 unimorph type in which the piezoelectric element is bonded to only one surface of the diaphragm, and can also be applied to a bimorph type in which the piezoelectric element is bonded to both of the diaphragms. .

  A specific piezoelectric sounding device of the present invention includes a piezoelectric vibrator, a support having an annular support, a connecting means, a drawing means, and a connecting 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 surface side 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 surface side of the diaphragm and the support portion. The lead-out means has a lead-out conductive portion electrically connected to the first electrode of the piezoelectric element. The connection means has a conductive part for connection electrically connected to the diaphragm of the piezoelectric element. And a connection means is formed with the synthetic resin sheet which has flexibility, and it arrange | positions ranging over the outer peripheral surface part and support part of a diaphragm so that a diaphragm can vibrate entirely. 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 a conductive layer 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. It is comprised by.

  In this case, since the electrically insulating layer and the lead conductive portion of the lead means are formed by a thick film or a thin film, the thickness dimension of the lead means drawn from the first electrode of the piezoelectric element can be reduced as compared with the conventional case. . Moreover, since the joining strength of the drawing means can be increased as compared with the prior art, a highly reliable piezoelectric sounder can be provided without using a reinforcing member as in the prior art.

  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 respectively 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 electrically connected to the surface of the diaphragm so as to leave the outer peripheral surface portion of the surface of the diaphragm. It is joined so that electrical conduction is possible. 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 diaphragm so as to leave a back surface outer peripheral surface portion of the back surface of the vibration plate. It is joined so that electrical conduction is possible. 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. The second lead means having the second lead conductive portion is used.

  According to this configuration, since the respective electrically insulating layers and the drawing conductive portions of the first drawing means and the second drawing means are formed of a thick film or a thin film, each of the first and second piezoelectric elements is formed. The thickness dimensions of the first extraction means and the second extraction means extracted from the first electrode can be reduced as compared with the conventional case. Further, since the bonding strength of the first drawing means and the second drawing means can be increased as compared with the conventional case, a highly reliable piezoelectric sounder can be provided without using a reinforcing member as in the conventional case.

  If the connecting means is arranged so as to cover the outer peripheral surface portion of the front surface side of the diaphragm, the outer peripheral surface portion of the front surface side is not exposed, so that 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, an electrical insulating layer may be formed so as to straddle the first electrode of the first piezoelectric element and the connecting means.

  The structure of the support is arbitrary, and 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. The support body may be configured to have the output electrode holding portion integrally with the support portion. In this case, the outer peripheral surface portion on the front surface side or the outer peripheral surface portion on the back surface side of the diaphragm and the second output electrode are electrically connected by a connecting means having a conductive portion for connection. This connecting means is composed of an electrically insulating layer and a connecting conductive portion. 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 conductive portion for connection is connected such that the front end 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 electrical insulating layer. A conductive layer formed of a thick film or a thin film can be used. If the electrically insulating layer and the connecting conductive portion of the connecting means are formed of a thick film or a thin film in this way, the thickness dimension of the connecting means between the diaphragm and the second output electrode can be reduced as compared with the conventional case. Further, the bonding strength between the diaphragm and the connecting means can be increased as compared with the conventional case.

  The first output electrode is configured to include an output electrode extension formed adjacent to the surface portion to which the connecting means of the support portion is connected and extending to the surface portion and the inner peripheral surface portion of the support portion, It is preferable to electrically connect the conductive layer constituting the lead conductive portion to the output electrode extension. 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 simply connected. It can be electrically connected by the structure.

  The output electrode extension is configured to extend to the back surface portion that opposes the surface portion of the support portion in the thickness direction, and the second output electrode extends over at least the surface portion, the inner peripheral surface portion, and the back surface portion of the support portion. Preferably formed. In this way, since the first and second output electrodes can be present on both the front surface portion and the back surface portion of the support portion, there is an advantage that the piezoelectric sound generator can be easily mounted on the circuit board. .

  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 electrically connected to the electrode portion formed on the inner peripheral surface portion of the support portion of the first output electrode. Therefore, the electrical connection between the second lead conductive portion and the first output electrode can be easily performed.

  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 manner, the support can be mass-produced by punching the substrate, and the first and second output electrodes can be easily formed using a known circuit pattern forming technique. Therefore, the cost of the support can be reduced as compared with the prior art.

  The connecting means is preferably composed of a flexible synthetic resin sheet having an annular portion joined to the surface of the support portion of the support via an adhesive layer. In this case, the piezoelectric vibrating body is supported with respect to 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 this. By doing so, the movement of the outer peripheral portion of the diaphragm is not substantially restrained, so that the amplitude of the diaphragm can be maximized.

  In addition, when comprising a connection means with a synthetic resin sheet, it is preferable to provide further the cyclic | annular protective layer fixed on the synthetic resin sheet so that a synthetic resin sheet may be pinched | interposed between support parts. If it does in this way, it can prevent that a synthetic resin sheet peels from a support part by a protective layer. In this case, the thickness dimension of the protective layer is determined so that the first piezoelectric element of the piezoelectric vibrating body and the first lead conductive portion can be completely accommodated in the space surrounded by the protective layer. preferable. In this way, when transported or automatically mounted on a circuit board or the like by an automatic mounting machine, the presence of the protective layer causes the first piezoelectric element and the first lead conductive portion of the piezoelectric vibrating body to exist. Since it can prevent that other parts contact, the defect rate of the product using a piezoelectric sounder can be reduced. This protective layer can be comprised from another synthetic resin sheet affixed on the synthetic resin sheet through the contact bonding layer, for example. If it does in this way, a protective layer can be arrange | positioned easily.

  The electrically insulating layer used for constituting the first and second extraction means is formed by a thick film formed by applying an insulating resin paste, and the conductive layer is formed by applying a conductive resin paste. May be formed. In this way, the electrically insulating layer and the conductive layer can be easily and inexpensively formed using the printing technique.

1 is a plan view of a piezoelectric sounder according to an embodiment of the present invention. (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. It is the III-III sectional view taken on the line of FIG. It is the IV-IV sectional view taken on the line of FIG. It is a figure which shows the wiring of the piezoelectric sounder shown in FIG. (A) is the schematic which shows a mode that the diaphragm of the piezoelectric speaker shown in FIG. 1 is vibrating, (B) shows a mode that the diaphragm of the piezoelectric speaker of a comparative example is vibrating. FIG. It is sectional drawing of the piezoelectric sounder of other embodiment of this invention. It is a top view of the connection means used for the piezoelectric sounder shown in FIG.

  Hereinafter, embodiments of the piezoelectric sounder of the present invention will be described in detail with reference to the drawings. 1A and 1B are a plan view and a bottom view of the piezoelectric sounding device according to the first embodiment of the present invention, and FIG. 3 is a cross-sectional view taken along line III-III in FIG. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 1, and FIG. 5 is a diagram showing wiring of the piezoelectric sounder of the present embodiment. In addition, in order to make an understanding easy, in FIG.3 and FIG.4, the thickness dimension of the one part part was exaggerated and drawn. As shown in the drawings, 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 1 integrally includes a support portion 5 and an output electrode holding portion 7, and is formed by stamping a substrate having a substantially equal thickness formed of an electrically insulating material such as a glass-epoxy resin substrate. It is formed by. The support portion 5 has an annular shape, and, as shown in FIG. 2 (B), two inner cross sections of the portion connected to the output electrode holding portion 7 have a semicircular arc shape. Recesses 5a and 5b are formed. The output electrode holding portion 7 includes electrode portions that are continuous with the front surface side regions 5c and 5d and the back surface side regions 5e and 5f connected to the two concave portions 5a and 5b. First and second layers made of gold-plated copper foil that constitutes part of the first and second output electrode components 13 and 15 are provided on the front surface regions 5c and 5d and the back surface regions 5e and 5f. Output electrodes 13a and 15a and first and second backside electrodes 13b and 15b are formed. As shown in FIGS. 3 and 4, conductive connection 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 that allows a diaphragm 17, a second piezoelectric element 21, and a second lead conductive portion 29, which will be described later, of the piezoelectric vibrator 3 to be completely accommodated.

  Further, a synthetic resin sheet 9 constituting a connecting means is joined to the surface 5g of the support portion 5 via an adhesive layer (not shown). The synthetic resin sheet 9 is made of an annular polyester tape having flexibility and having an adhesive on one side. The synthetic resin sheet 9 includes an annular portion 9a that is joined to the support portion 5, and a vibrator joint portion 9b that is located on the inner peripheral side of the annular portion 9a and to which the piezoelectric vibrator 3 is joined. 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 that allows a first piezoelectric element 19 (described later) and a first lead conductive portion 23 of the piezoelectric vibrator 3 to be completely accommodated.

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

  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 the diaphragm 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 made of an iron-nickel alloy. 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. . 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 first electrode 21a on the front surface and a plurality of piezoelectric ceramic layers and electrode layers alternately laminated so that 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 21 b is joined to the back surface 17 b of the vibration plate 17 so as to be electrically conductive so as to leave the back surface side outer peripheral surface portion 17 d of the back surface 17 b of the vibration plate 17. An annular surface-side outer peripheral surface portion 17c of the surface 17a of the diaphragm 17 is joined to a surface adjacent to the support portion 5 of the vibration body joint portion 9b of the synthetic resin sheet (connecting means) 9 described above. As a result, the outer peripheral surface portion 17c of the vibration plate 17 and the support 1 are connected by the synthetic resin sheet 9, and the piezoelectric vibration member 3 has the front surface 17a and the back surface 17b of the vibration plate 17 in contact with the support portion 5. Without being supported by the support portion 5 by the synthetic resin sheet 9. 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.

  The first electrode 19 a of the first piezoelectric element 19 and the first output electrode 13 are electrically connected by the first extraction means 23. The first lead means 23 includes an electrical insulation layer 25 and a first lead conductive portion 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 across the first electrode 19a of the first piezoelectric element 19, the outer peripheral surface portion 17c of the vibration plate 17 and the synthetic resin sheet 9, and the vicinity of the center of the first electrode 19a and the first electrode 19a. 1 between the output electrodes 13a. The first lead conductive portion 27 is a thick conductive film formed by applying a conductive resin paste made of resin-silver paste or the like. The leading portion 27a of the first lead conductive portion 27 is connected to the first electrode 19a of the first piezoelectric element 19 in the vicinity of the center of the first electrode 19a, and the rear end portion 27b is the first output electrode. 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 electrical insulating layer 31 and a second lead conductive portion 33 formed on the electrical 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 back surface side outer peripheral surface portion 17d 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 made of resin-silver paste or the like. 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. The first output electrode constituting part 13 is connected to the conductive connection part 13 c of the output electrode extension part. The remainder is located on the electrical insulating layer 31. Thereby, 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.

  The diaphragm 17 and the second output electrode 15 are electrically connected by connection means 35. The connection means 35 has an electrically insulating layer 37 and a connecting conductive portion 39 formed on the electrically insulating layer. The electrical 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 outer peripheral surface portion 17 d 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 made of resin-silver paste or the like. The leading end 39a of the connecting conductive portion 39 is connected to the rear outer peripheral surface portion 17d, and the rear end 39b is connected to the conductive connecting portion 15c of the output electrode extension portion of the second output electrode constituting portion 15 on the groove 5b. It is connected. The remainder is located on the electrical insulating layer 37.

FIG. 6A is a schematic view showing a state in which the diaphragm 17 of the piezoelectric sounder of this example is vibrating, and FIG. 6B is a diagram showing the diaphragm on the surface of the support portion R5 via an adhesive. It is the schematic which shows a mode that the diaphragm R17 of the piezoelectric speaker of the comparative example (for example, Unexamined-Japanese-Patent No. 2003-78995) which connected R17 is vibrating. From both figures, it can be seen that the amplitude f ₁ of the piezoelectric speaker of this example shown in FIG. 6A is larger than the amplitude f ₂ of the piezoelectric speaker of the comparative example shown in FIG. 6B. This is because in the piezoelectric sounder of this example, the front surface 17 a and the back surface 17 b 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 insulation layer 25 and the first lead conductive portion 27 of the first lead means 23 and the electrical insulation layer 31 and the second lead of the second lead means 29 are used. Since the conductive portion 33 is formed of a thick film, the conductive portion (first extraction means) between the first electrodes 19a, 21a of the first and second piezoelectric elements 19, 21 and the first output electrode 13 is used. 23 and the second drawing means 29) can be made smaller in thickness than in the prior art. Further, 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 conventional case.

  FIG. 7 is a cross-sectional view of a piezoelectric sounding device according to another embodiment (second embodiment) of the present invention. The piezoelectric sounder of this example uses a unimorph type piezoelectric element in which the piezoelectric element 119 is bonded only to one surface 117 a of the diaphragm 117. Moreover, as a connection means, as shown in FIG. 8, the thing provided with the 1st wiring pattern 151 and the 2nd wiring pattern 153 on the 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 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.

  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. And the front-end | tip part 151a of the 1st wiring pattern 151 is electrically joined to the 1st electrode 119a of the piezoelectric element 119 through the thick film part 155 formed using the electrically conductive paste. The rear end portion 151b of the first wiring pattern 151 is electrically joined to the first output electrode 113a through a thick film portion 157 formed using a conductive paste.

  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. And the front-end | tip part 153a of the 2nd wiring pattern 153 is electrically joined to the surface 117a of the diaphragm 117 of the piezoelectric element 119 through the thick film part formed using the electrically 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 153 is used. Thus, the diaphragm 117 of the piezoelectric element 119 can be connected 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 each part is performed by the thick film part formed using the conductive paste. However, the connection of each part by soldering or the like is performed. You can go. 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. 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 electrical 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 conductive portion are formed using a technique such as sputtering or vapor deposition. Of course, the connecting conductive portion may be formed of a thin film. Moreover, it can also form with metal foil, such as copper foil.

  In the first embodiment, a bimorph type piezoelectric element is employed. In the second embodiment, a unimorph type piezoelectric element is employed. However, the present invention can employ any type of piezoelectric element. In the first embodiment, a unimorph type piezoelectric element may be employed, and in the second embodiment, a bimorph type piezoelectric element may be employed.

  In each of the above embodiments, the support 1 is formed using an insulating material made of glass-epoxy resin. However, the support may be formed using a conductive material such as metal. In this case, an insulating layer may be formed on the surface of the conductive material, and an output electrode may be formed on the insulating layer.

  According to the present invention, the diaphragm is supported by the support via the connecting means without the outer peripheral portion 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.

In addition, 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 prior art. Moreover, since the joining strength of the drawing means can be increased as compared with the prior art, a highly reliable piezoelectric sounder can be provided without using a reinforcing member as in the prior art.

Claims (8)

A metal diaphragm having a front surface and a back surface;
A first electrode is provided on the front surface and a second electrode is provided on the back surface, and the second electrode is electrically connected to the front 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;
A first electrode is provided on the front surface and a second electrode is provided on the rear surface, and the second electrode is electrically connected to the rear surface of the diaphragm so as to leave a rear surface side outer peripheral surface portion of the rear 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 vibration plate 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 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, the outer peripheral surface portion of the surface side, and the connection means. The first lead conductive portion is thick so that its tip is connected to the first electrode of the first piezoelectric element and at least a portion of the remaining portion is located on the electrically insulating layer. Or a conductive layer formed of a thin film,
The second extraction means has 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 is formed of a thick film or a thin film so that the tip portion is connected to the first electrode of the second piezoelectric element and the remaining portion is located on the electrically insulating layer. Composed of a conductive layer formed ,
The support includes an output electrode having 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. It has a holding part integrally with the support part,
The front-surface-side outer peripheral surface portion or the rear-surface-side outer peripheral surface portion of the diaphragm and the second output electrode are electrically connected by a connection means having a connection conductive portion,
The connection means includes an electrically insulating layer formed of a thick film or a thin film so as to straddle the front-side outer peripheral surface portion or the rear-surface-side outer peripheral surface portion of the diaphragm and the coupling means, and the connection conductive portion The front end is connected to the front outer peripheral surface or the rear outer peripheral surface, the rear end is connected to the second output electrode, and the remaining portion is positioned on the electrical insulating layer. Consists of a conductive layer formed by a film or thin film,
The first output electrode includes an output electrode extension formed adjacent to a surface portion to which the connecting means of the support portion is connected and extending to the surface portion and an inner peripheral surface portion of the support portion. ,
The conductive layer constituting the second lead conductive portion is electrically connected to the output electrode extension;
The output electrode extension extends to the back surface portion facing the surface portion of the support portion in the thickness direction,
The piezoelectric output device, 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 .   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 on the inner peripheral surface portion of the support portion of the first output electrode. The piezoelectric sounding device according to claim 1, wherein the piezoelectric sounding device is electrically connected to an electrode portion formed on the substrate. The support is constituted by a substrate formed of an electrically insulating material and having a substantially equal 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 piezoelectric vibrating body is formed by the connecting means so that the diaphragm does not contact the inner peripheral surface of the support portion and the diaphragm and the second piezoelectric element are accommodated in the support portion. The piezoelectric sounding device according to claim 1, wherein the piezoelectric sounding device is supported with respect to the support portion. It further comprises an annular protective layer fixed on the synthetic resin sheet so as to sandwich the synthetic resin sheet with the support part,
2. The piezoelectric sounder according to claim 1, wherein the protective layer has a thickness dimension in which the first piezoelectric element and the first lead conductive portion of the piezoelectric vibrating body are completely accommodated. The piezoelectric sounding device according to claim 4 , wherein the protective layer is made of another synthetic resin sheet attached on the synthetic resin sheet via an adhesive layer.   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. Piezoelectric sound generator. A piezoelectric vibrating body in which a piezoelectric element is bonded to a 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,
Said connecting means are formed by a synthetic resin sheet having flexibility, the diaphragm is disposed across the outer peripheral surface of said diaphragm so as to entirely vibrate with said supporting portion, said 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 that extends over the first electrode beyond the outer peripheral surface portion of the vibrator,
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,
The piezoelectric sound generator, wherein the first wiring pattern extends on the extension portion of the synthetic resin sheet . The piezoelectric sounding device according to claim 7 , wherein the piezoelectric element is a unimorph type or bimorph type piezoelectric element.

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