JP2007336504A

JP2007336504A - Diaphragm

Info

Publication number: JP2007336504A
Application number: JP2006188596A
Authority: JP
Inventors: Taiichi Tokuhisa; 泰一徳久; Yoshiyuki Watabe; 嘉幸渡部
Original assignee: Taiyo Yuden Co Ltd
Current assignee: Taiyo Yuden Co Ltd
Priority date: 2006-06-12
Filing date: 2006-06-12
Publication date: 2007-12-27

Abstract

PROBLEM TO BE SOLVED: To provide a diaphragm in which the occurrence of an adhesion error or a connection defect with a piezoelectric element can be prevented by preventing the blocking of wetting and the spreading of an adhesive caused by the damming of the adhesive. SOLUTION: The present invention relates to a diaphragm 10 including an approximately disk-shaped insulated substrate 12 for sticking a disk-shaped piezoelectric element 30 thereon and a film-like electrode 15 formed on at least one principal surface of the insulated substrate connected with an electrode 29 of the piezoelectric element, wherein a recess 14 is formed beforehand near an edge within a region 13 where the electrode 15 is formed on the principal surface of the insulated substrate and at least a part of film thickness of the electrode near the edge is housed within the recess. Therefore, at least a part of the formation of a projection is suppressed by absorbing a portion corresponding to the projection of the connecting electrode 15 closer to the outer circumference of a print film thickness by the recess 14 and damming of the adhesive 16 used for sticking the piezoelectric element 30 caused by the projection is prevented. COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、圧電レシーバ、圧電サウンダ、圧電スピーカ、圧電マイクロホンなどの圧電型電気音響変換器に用いられる振動板に関し、さらに具体的には、振動板と圧電素子とを接着するための接着剤の濡れ広がりの改善に関するものである。 The present invention relates to a diaphragm used for a piezoelectric electroacoustic transducer such as a piezoelectric receiver, a piezoelectric sounder, a piezoelectric speaker, and a piezoelectric microphone, and more specifically, an adhesive for bonding the diaphragm and the piezoelectric element. It relates to the improvement of wetting spread.

圧電型のスピーカやマイクロホン等の圧電型電気音響変換器は、簡易な電気音響変換手段として広く利用されており、特に近年は、携帯電話や携帯情報端末などの分野でスピーカ等として多用されている。
圧電型電気音響変換器に用いられる振動板１は、図１２（特許文献１）に示されるように、銀や銅等の導電性粒子を含有した導電性ペーストを樹脂フィルム等のフレキシブル基板２の表面に直接印刷して形成した電極パターン５が設けられている。また、前記振動板１を用いた圧電振動板７は、図１３及び図１４に示されるように、圧電セラミック板の両面に導電性ペーストが塗布され電極９Ａ，９Ｂが形成された圧電素子８が嫌気性の紫外線硬化型の接着剤６等を用いて前記振動板１の電極パターン５上に接着される。Piezoelectric electroacoustic transducers such as piezoelectric speakers and microphones are widely used as simple electroacoustic transducing means, and in recent years, they are widely used as speakers and the like in the field of mobile phones and personal digital assistants. .
As shown in FIG. 12 (Patent Document 1), a diaphragm 1 used in a piezoelectric electroacoustic transducer is made of a conductive paste containing conductive particles such as silver or copper, and a flexible substrate 2 such as a resin film. An electrode pattern 5 formed by printing directly on the surface is provided. Further, as shown in FIGS. 13 and 14, the piezoelectric diaphragm 7 using the diaphragm 1 has a piezoelectric element 8 in which conductive paste is applied on both surfaces of the piezoelectric ceramic plate to form electrodes 9A and 9B. It adhere | attaches on the electrode pattern 5 of the said diaphragm 1 using the anaerobic ultraviolet curing adhesive 6 grade | etc.,.

具体的には、円形の絶縁体２の一方の主面に圧電素子８の一方の電極９Ａと接続するための電極パターン５が設けられるとともに該絶縁体２の外周方向に延出された凸部２Ａに前記電極パターン５の引き出し部５Ａと、前記圧電素子８の他方の電極９Ｂに導電接続するための引き出し電極５Ｂとが設けられており、前記振動板１の電極パターン５上に前記圧電素子８の電極９Ａが重なるように接着剤６により固定される。このとき、振動板１に塗布された接着剤６は前記振動板１と前記圧電素子８とで挟まれて薄く圧し拡げられることにより、振動板１の電極パターン５の表面の微細な凹凸と前記圧電素子８の電極９Ａの表面の微細な凹凸とが相互に接触して導電接続される。また、圧電素子８の他方の電極９Ｂは前記絶縁体２の凸部２Ａに設けられた引き出し電極５Ｂに錦糸線Ｗ等により導電接続される。
特開平９−１８２１８９号公報 Specifically, an electrode pattern 5 for connecting to one electrode 9A of the piezoelectric element 8 is provided on one main surface of the circular insulator 2, and a convex portion extending in the outer peripheral direction of the insulator 2 2A is provided with a lead portion 5A of the electrode pattern 5 and a lead electrode 5B for conductive connection to the other electrode 9B of the piezoelectric element 8, and the piezoelectric element is provided on the electrode pattern 5 of the diaphragm 1. The eight electrodes 9A are fixed by the adhesive 6 so as to overlap. At this time, the adhesive 6 applied to the diaphragm 1 is sandwiched between the diaphragm 1 and the piezoelectric element 8 and is thinly pressed and spread, so that the fine irregularities on the surface of the electrode pattern 5 of the diaphragm 1 and the above-described The fine irregularities on the surface of the electrode 9A of the piezoelectric element 8 are in contact with each other to be conductively connected. The other electrode 9B of the piezoelectric element 8 is conductively connected to a lead electrode 5B provided on the convex portion 2A of the insulator 2 by a tinsel wire W or the like.
Japanese Patent Laid-Open No. 9-182189

しかしながら、上記のような背景技術では、絶縁性フィルム等のフレキシブル基板２の表面にスクリーン印刷法により電極材料ペーストを塗布し、加熱・硬化して電極パターン５を形成すると、一般にサドル現象と呼ばれるように図１２（Ｒ）に厚み方向を拡大した断面図で示されるように電極パターン５の印刷膜の縁部近傍に該印刷膜の厚みが中央部分に比べて厚い盛り上り５Ｃが形成される。次に、図１４に厚み方向を拡大した断面図で示されるように前記電極パターン５上に圧電素子８を接着するための接着剤６を塗布して圧電素子８を重ねて貼り合わせると、前記電極パターン５の印刷膜の縁部近傍の環状の盛り上がり５Ｃにより前記塗布された接着剤６がせき止められて濡れ拡がりが阻害され、振動板１と圧電素子８との接着ミスや、前記振圧電素子８の電極９Ａと前記振動板１の電極パターン５との接続不良が生じやすいという課題があった。 However, in the background art as described above, when an electrode material paste is applied to the surface of the flexible substrate 2 such as an insulating film by a screen printing method and heated and cured to form the electrode pattern 5, it is generally called a saddle phenomenon. As shown in FIG. 12R, which is a cross-sectional view in which the thickness direction is enlarged, a swell 5C is formed in the vicinity of the edge of the printed film of the electrode pattern 5 where the thickness of the printed film is larger than that of the central portion. Next, as shown in a cross-sectional view in which the thickness direction is enlarged in FIG. 14, when the adhesive 6 for bonding the piezoelectric element 8 is applied on the electrode pattern 5 and the piezoelectric element 8 is laminated and bonded together, The applied adhesive 6 is blocked by the annular bulge 5C in the vicinity of the edge of the printed film of the electrode pattern 5 to inhibit wetting and spreading, and the bonding error between the vibration plate 1 and the piezoelectric element 8 or the vibration piezoelectric element There is a problem that poor connection between the 8 electrodes 9A and the electrode pattern 5 of the diaphragm 1 is likely to occur.

本発明は、以上の点に着目したもので、その目的は、接着剤がせき止められて濡れ広がりが阻害されるのを防止して、圧電素子との接着ミスや接続不良の発生を防止することが可能な振動板を提供することにある。 The present invention pays attention to the above points, and its purpose is to prevent the adhesive from being dammed up and obstructing the spread of wetting, and to prevent the occurrence of bonding errors and poor connection with the piezoelectric element. It is in providing the diaphragm which can do.

前記目的を達成するため、本発明は、
（１）板状の圧電素子を貼着するための絶縁基板と、前記圧電素子の電極と接続するために前記絶縁基板の少なくとも一方の主面上に形成された膜状の電極と、を有する振動板において、
前記絶縁基板の主面の前記電極の形成される領域内の該領域の縁部近傍に予め凹部が形成されており、前記電極の縁部近傍の膜厚の少なくとも一部が前記凹部内に収容されていることを特徴とする。（・・・以下、第１の課題解決手段と称する。）In order to achieve the above object, the present invention provides:
(1) having an insulating substrate for adhering a plate-like piezoelectric element, and a film-like electrode formed on at least one main surface of the insulating substrate to connect to the electrode of the piezoelectric element In the diaphragm,
A recess is formed in advance in the vicinity of the edge of the region of the main surface of the insulating substrate in the region where the electrode is formed, and at least a part of the film thickness in the vicinity of the edge of the electrode is accommodated in the recess. It is characterized by being. (... hereinafter referred to as first problem solving means)

また、主要な形態の一つは、
（２）前記凹部が前記領域の縁部に沿って帯状に形成されていることを特徴とする。（・・・以下、第２の課題解決手段と称する。）One of the main forms is
(2) The concave portion is formed in a strip shape along the edge of the region. (Hereinafter referred to as second problem solving means)

また、他の主要な形態の一つは、
（３）前記凹部が前記領域の縁部に沿って互いに離間して複数形成されていることを特徴とする。（・・・以下、第３の課題解決手段と称する。）One of the other main forms is
(3) A plurality of the recesses are formed apart from each other along the edge of the region. (Hereinafter referred to as third problem solving means)

また、他の主要な形態の一つは、
（４）前記絶縁基板が複数の絶縁体層を備えた積層体からなり、前記凹部は前記複数の絶縁体層のうちの少なくとも一つの絶縁体層に貫通孔が形成されたものであることを特徴とする。（・・・以下、第４の課題解決手段と称する。）One of the other main forms is
(4) The insulating substrate is made of a laminated body having a plurality of insulator layers, and the recess has a through hole formed in at least one insulator layer of the plurality of insulator layers. Features. (Hereinafter referred to as fourth problem solving means)

また、他の形態の一つは、
（５）前記絶縁基板が複数の絶縁体層と該複数の絶縁体層の層間に配置された少なくとも一つの内部導体層との積層体からなり、前記絶縁体層に形成された貫通孔を介して前記電極と前記内部導体層とが接続されていることを特徴とする。（・・・以下、第５の課題解決手段と称する。）One of the other forms is
(5) The insulating substrate comprises a laminate of a plurality of insulator layers and at least one internal conductor layer disposed between the plurality of insulator layers, and through a through hole formed in the insulator layer. The electrode and the inner conductor layer are connected to each other. (Hereinafter referred to as fifth problem solving means)

上記第１の課題解決手段による作用は次の通りである。すなわち、前記絶縁基板の主面の前記電極の形成される領域内の該領域の縁部近傍に予め凹部が形成されており、前記電極の縁部近傍の膜厚の少なくとも一部が前記凹部内に収容されているので、電極の印刷膜の縁部近傍の盛り上がりの少なくとも一部の発生が抑制され、圧電素子の貼り合わせに用いる接着剤がせき止められるのが抑制される。 The operation of the first problem solving means is as follows. That is, a recess is formed in advance in the vicinity of the edge of the region of the main surface of the insulating substrate in the region where the electrode is formed, and at least a part of the film thickness in the vicinity of the edge of the electrode is in the recess. Therefore, at least a part of the bulge in the vicinity of the edge of the printed film of the electrode is suppressed, and the adhesive used for bonding the piezoelectric elements is suppressed from being clogged.

上記第２の課題解決手段による作用は次の通りである。すなわち、前記凹部が前記領域の縁部に沿って帯状に形成されているので、前記電極の印刷膜の縁部近傍の盛り上がりの発生が防止され、接着剤が均一に濡れ広がることができる。このため、所定の厚みの圧電振動板を安定して取得することができ、例えば音圧バラツキ等が低減できる。 The operation of the second problem solving means is as follows. That is, since the concave portion is formed in a band shape along the edge of the region, the occurrence of swell in the vicinity of the edge of the printed film of the electrode is prevented, and the adhesive can be spread evenly. For this reason, a piezoelectric diaphragm having a predetermined thickness can be obtained stably, and for example, variations in sound pressure can be reduced.

上記第３の課題解決手段による作用は次の通りである。すなわち、前記凹部が前記領域の縁部に沿って互いに離間して複数形成されているので、凹部の形成に伴って前記振動板の強度が局部的に低下するのを抑制することができる。 The operation of the third problem solving means is as follows. That is, since a plurality of the recesses are formed apart from each other along the edge of the region, it is possible to suppress a local decrease in strength of the diaphragm due to the formation of the recess.

上記第４の課題解決手段による作用は次の通りである。すなわち、前記絶縁基板が複数の絶縁体層を備えた積層体からなり、前記凹部が前記複数の絶縁体層のうちの少なくとも一つの絶縁体層に貫通孔が形成されたものであるので、前記膜状の電極の膜厚の一部が所定の厚み寸法で充填され、振動板の一方の主面上の電極膜の厚み寸法が均一となる。 The operation of the fourth problem solving means is as follows. That is, since the insulating substrate is composed of a laminate including a plurality of insulator layers, and the concave portion is formed with a through hole in at least one insulator layer of the plurality of insulator layers, A part of the film thickness of the film-like electrode is filled with a predetermined thickness dimension, and the thickness dimension of the electrode film on one main surface of the diaphragm becomes uniform.

上記第５の課題解決手段による作用は次の通りである。すなわち、前記絶縁体層に形成された貫通孔を介して前記電極と前記内部導体層とが接続されているので、振動板の表面の電極配置に関わらず任意の方向に電極の引き出しを行うことができる。
本発明の前記及び他の目的，特徴，利点は、以下の詳細な説明及び添付図面から明瞭になろう。The operation of the fifth problem solving means is as follows. That is, since the electrode and the inner conductor layer are connected through a through hole formed in the insulator layer, the electrode can be drawn out in any direction regardless of the electrode arrangement on the surface of the diaphragm. Can do.
The above and other objects, features and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings.

上述したように本発明の振動板は、電極の印刷膜の縁部近傍の盛り上がりの少なくとも一部の発生が抑制され、圧電素子の貼り合わせに用いる接着剤がせき止められるのが抑制され、振動板と圧電素子との接着ミスや振動板の電極と振動板の電極との接続不良の発生を防止することができる。 As described above, the diaphragm of the present invention suppresses the occurrence of at least a part of the bulge in the vicinity of the edge of the printed film of the electrode, suppresses the clogging of the adhesive used for bonding the piezoelectric element, and the diaphragm. It is possible to prevent the occurrence of a bonding error between the piezoelectric element and the poor connection between the diaphragm electrode and the diaphragm electrode.

次に、本発明の振動板の第１の実施形態について、図１〜図４を参照して説明する。図１は第１の実施形態の振動板１０に用いる絶縁基板１２の全体構造を示す図である。図１（Ａ）は前記絶縁基板１２の平面図であり、図１（Ｂ）は前記絶縁基板１２の上記図１（Ａ）におけるＢ−Ｂ線の厚み方向を拡大した断面図である。図２は本実施形態の振動板１０の全体構造を示す図である。図２（Ｃ）は前記振動板１０の平面図であり、図２（Ｄ）は前記振動板１０の上記図２（Ｃ）におけるＤ−Ｄ線の厚み方向を拡大した断面図である。図３は本実施形態の振動板１０に圧電素子３０を貼り合わせた状態の圧電振動板２０の外観を示す斜視図であり、図４は前記圧電振動板２０の上記図３におけるＦ−Ｆ線の厚み方向を拡大した断面図である。 Next, a first embodiment of the diaphragm of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing the overall structure of an insulating substrate 12 used in the diaphragm 10 of the first embodiment. FIG. 1A is a plan view of the insulating substrate 12, and FIG. 1B is an enlarged cross-sectional view of the insulating substrate 12 in the thickness direction of line BB in FIG. 1A. FIG. 2 is a diagram illustrating the overall structure of the diaphragm 10 of the present embodiment. FIG. 2C is a plan view of the diaphragm 10, and FIG. 2D is a cross-sectional view of the diaphragm 10 in which the thickness direction of the DD line in FIG. 2C is enlarged. 3 is a perspective view showing the appearance of the piezoelectric diaphragm 20 in a state where the piezoelectric element 30 is bonded to the diaphragm 10 of the present embodiment, and FIG. 4 is a FF line of the piezoelectric diaphragm 20 in FIG. It is sectional drawing to which the thickness direction of was expanded.

本発明の振動板の第１の実施形態は、図１に示すように、略円板状の絶縁基板１２にその外周方向に延出された凸部１２Ａが形成されている。また、該絶縁基板１２の両主面には、一点鎖線で囲まれるように、円板状の圧電素子３０の電極２９と接続するための電極が形成される領域１３がそれぞれ一対設けられている。前記電極が形成される領域１３内にはそれぞれ、該領域１３の前記一点鎖線で示される縁部の近傍に凹部１４が帯状に形成されている。そして、図２に示すように、前記凹部１４に重なるように膜状の電極１５が印刷形成されている。 In the first embodiment of the diaphragm of the present invention, as shown in FIG. 1, a convex portion 12 A extending in the outer circumferential direction is formed on a substantially disc-shaped insulating substrate 12. In addition, a pair of regions 13 where electrodes for connecting to the electrodes 29 of the disk-shaped piezoelectric element 30 are formed are provided on both main surfaces of the insulating substrate 12 so as to be surrounded by a one-dot chain line. . In each of the regions 13 where the electrodes are formed, a recess 14 is formed in a band shape in the vicinity of the edge portion indicated by the one-dot chain line of the region 13. As shown in FIG. 2, a film-like electrode 15 is printed and formed so as to overlap the concave portion 14.

具体的には、円板状の圧電素子３０を貼着するための略円板状の絶縁基板１２と、前記圧電素子３０の電極２９と接続するために前記絶縁基板１２の少なくとも一方の主面に形成された膜状の電極１５と、を有する振動板１０において、前記絶縁基板１２の主面の前記電極１５の形成される領域１３内の該領域１３の縁部近傍に予め凹部１４が形成されており、前記電極１５の縁部近傍の膜厚の少なくとも一部が前記凹部１４内に収容されているものである。 Specifically, the substantially disk-shaped insulating substrate 12 for attaching the disk-shaped piezoelectric element 30 and at least one main surface of the insulating substrate 12 for connection to the electrode 29 of the piezoelectric element 30 In the diaphragm 10 having the film-like electrode 15 formed on the surface, the recess 14 is formed in advance in the vicinity of the edge of the region 13 in the region 13 where the electrode 15 is formed on the main surface of the insulating substrate 12. In other words, at least a part of the film thickness in the vicinity of the edge of the electrode 15 is accommodated in the recess 14.

また、上記第１の実施形態は、前記凹部１４が前記領域１３の縁部に沿って帯状に形成されているものである。 In the first embodiment, the recess 14 is formed in a band shape along the edge of the region 13.

より具体的には、略円板状の絶縁基板１２には、上述したように、外周方向に延出された凸部１２Ａが形成されており、該絶縁基板１２の両主面には、円板状の圧電素子３０の一対の半円形の電極２９と接続するための一点鎖線で示される略半円形の電極１５が形成される領域１３がそれぞれ線対称に一対設けられている。前記電極１５が形成される領域１３内にはそれぞれ、該領域の縁部近傍に予め該縁部に沿って凹部１４が平面視形状が略Ｄ字形になるように帯状に形成されている。そして、図２に示すように、前記絶縁基板１２の両主面に前記凹部１４に重なるように、電極１５がそれぞれ印刷により膜状に形成されるとともに、該電極１５の縁部近傍の膜厚の少なくとも一部が前記凹部１４内に収容されている。また、前記絶縁基板１２の外周方向に延出された凸部１２Ａ上には、前記一対の電極１５からそれぞれ引き出し部１５Ａが延出されている。 More specifically, as described above, the substantially disc-shaped insulating substrate 12 is formed with the convex portions 12A extending in the outer peripheral direction, and both main surfaces of the insulating substrate 12 are circular. A pair of regions 13 each having a substantially semicircular electrode 15 indicated by a one-dot chain line for connection to a pair of semicircular electrodes 29 of the plate-like piezoelectric element 30 are provided in line symmetry. In each region 13 where the electrode 15 is formed, a recess 14 is formed in advance in the vicinity of the edge of the region along the edge so that the shape in plan view is substantially D-shaped. Then, as shown in FIG. 2, the electrodes 15 are formed in a film shape by printing so as to overlap the concave portions 14 on both main surfaces of the insulating substrate 12, and the film thickness in the vicinity of the edge of the electrode 15. At least a portion thereof is accommodated in the recess 14. In addition, a lead portion 15 A extends from the pair of electrodes 15 on the convex portion 12 A extending in the outer peripheral direction of the insulating substrate 12.

本実施形態の振動板１０は、上述のように形成されているので、電極１５の印刷膜厚の縁部近傍の盛り上がりに相当する部分が前記凹部１４に吸収されて、前記電極１５の印刷膜の上面が平坦となっている。 Since the diaphragm 10 of the present embodiment is formed as described above, a portion corresponding to the bulge in the vicinity of the edge of the printed film thickness of the electrode 15 is absorbed by the concave portion 14, and the printed film of the electrode 15. The upper surface of is flat.

次に、前記第１の実施形態の振動板１０を用いた圧電振動板２０は、図３及び図４に示されるように、振動板１０の両主面に、圧電体層２８と一対の電極２９とが交互に積層された圧電素子３０がそれぞれエポキシ系の絶縁性の接着剤１６を用いて接着され、前記振動板１０の電極１５と前記圧電素子３０の電極２９とが導電接続されている。
このとき、塗布された接着剤１６は、前記振動板１０の印刷膜の縁部近傍に盛り上がりがないので、接着剤がせき止められることがなく、前記電極１５と前記圧電素子３０の電極２９とで圧し拡げられて、前記電極１５の縁部の外側まで濡れ拡がっている。このため、振動板１０の電極１５の表面の微細な凹凸と前記圧電素子３０の電極２９の表面の微細な凹凸とが相互に接触して導電接続されている。Next, the piezoelectric diaphragm 20 using the diaphragm 10 of the first embodiment has a piezoelectric layer 28 and a pair of electrodes on both main surfaces of the diaphragm 10, as shown in FIGS. The piezoelectric elements 30 alternately stacked with 29 are bonded using an epoxy insulating adhesive 16, and the electrode 15 of the diaphragm 10 and the electrode 29 of the piezoelectric element 30 are conductively connected. .
At this time, since the applied adhesive 16 does not swell in the vicinity of the edge of the printed film of the vibration plate 10, the adhesive is not blocked, and the electrode 15 and the electrode 29 of the piezoelectric element 30 The electrode 15 is pressed and expanded to the outside of the edge of the electrode 15. For this reason, the fine irregularities on the surface of the electrode 15 of the diaphragm 10 and the fine irregularities on the surface of the electrode 29 of the piezoelectric element 30 are in contact with each other and are conductively connected.

上記振動板１０としては、絶縁性であって可撓性を有する材料、例えばＰＥＴ（ＰｏｌｙＥｔｈｙｌｅｎｅＴｅｒｅｐｈｔａｌａｔｅ）などの絶縁フィルムが好ましいが、ＰＥＴに限定するものではなく、ＰＥＮ，ポリイミド、アミド、等耐熱性を有する絶縁性樹脂フィルムの中から適宜選択して用いることができる。厚みは２５μｍ〜１００μｍが好ましい。 The diaphragm 10 is preferably an insulating and flexible material, for example, an insulating film such as PET (PolyEthylene Terephthalate), but is not limited to PET, PEN, polyimide, amide, etc. It can select from the insulating resin film which has these, and can use it suitably. The thickness is preferably 25 μm to 100 μm.

また、上記振動板１０として、複数の絶縁体層と内部導体層とが積層された積層構造のフレキシブル基板等を用いることもできる。この場合に、複数の絶縁体層の層間に設けた内部導体層は、圧電素子振動板を駆動回路に接続するための電極の引き出し部として利用することもできる。 As the diaphragm 10, a flexible substrate having a laminated structure in which a plurality of insulator layers and internal conductor layers are laminated can be used. In this case, the internal conductor layer provided between the plurality of insulator layers can be used as an electrode lead-out portion for connecting the piezoelectric element diaphragm to the drive circuit.

上記振動板１０の絶縁基板１２の少なくとも一方の主面上に形成された膜状の電極１５としては、Ａｇ、Ｎｉ，Ｃｕ，Ａｌ等の導電性を有する金属粉末と、紫外線硬化性樹脂、熱硬化性樹脂等の絶縁性樹脂と、を主成分とする導電性樹脂が好ましく、特に、Ａｇ粉末を含有するポリマー性導電ペーストを用いて形成することが好ましい。前記導電性を有する金属粉末と前記絶縁性樹脂と溶剤とを混合した導電性樹脂ペーストを塗布し、乾燥した後、必要により紫外線照射や加熱し、硬化させることにより形成することができる。
また、上記電極の厚みは、４〜２０μｍが好ましい。The film-like electrode 15 formed on at least one main surface of the insulating substrate 12 of the diaphragm 10 includes conductive metal powder such as Ag, Ni, Cu, Al, ultraviolet curable resin, heat A conductive resin containing an insulating resin such as a curable resin as a main component is preferable, and it is particularly preferable to use a polymer conductive paste containing Ag powder. It can be formed by applying a conductive resin paste in which the conductive metal powder, the insulating resin, and a solvent are mixed, drying, and then curing with ultraviolet irradiation or heating as necessary.
The thickness of the electrode is preferably 4 to 20 μm.

上記振動板１０の凹部１４としては、前記電極が形成される領域内の該領域の縁部近傍に予め形成されていればよく、前記両域の縁部に沿って形成されていることが好ましい。
前記凹部１４の深さは、前記電極１５の印刷膜のその他の部分からの厚み方向の盛り上がり部分の高さと同程度とすることが好ましい。また、前記凹部１４の幅は、前記盛り上がり部分の幅以上とすることが好ましく、具体的には、０．５ｍｍ〜２．０ｍｍが好ましい。The concave portion 14 of the diaphragm 10 may be formed in advance in the vicinity of the edge of the region in the region where the electrode is formed, and is preferably formed along the edge of the two regions. .
It is preferable that the depth of the concave portion 14 is approximately the same as the height of the raised portion in the thickness direction from the other portion of the printed film of the electrode 15. Moreover, it is preferable that the width | variety of the said recessed part 14 shall be more than the width | variety of the said swelling part, and, specifically, 0.5 mm-2.0 mm are preferable.

また、上記絶縁基板１２への凹部１４の形成は、打ち抜きプレスを用いた前記絶縁基板の打ち抜きと同時、またはこの工程に前後して、加圧ピンの押し込みや切削加工により形成することができる。また、前記に限らず、前記絶縁基板の表面にレーザ光を照射して凹部１４を形成することもできる。
凹部１４の断面形状は、特に制限はなく、矩形、すり鉢状、半円形等、各種断面を有するものであってもよく、さらに、凹部１４の縁に面取りやＲ付けを施したものであってもよい。
また、前記振動板１０として積層構造のプリント基板を用いる場合には、積層する複数の絶縁体層のうちの一部の絶縁体層に該絶縁体層を貫通する孔を予め設けた後に積層するか、あるいは、前記積層構造のプリント基板を形成した後に、エッチングや切削加工により前記一部の絶縁体層を貫通する孔を形成してもよい。The concave portion 14 can be formed on the insulating substrate 12 by pressing a pressure pin or by cutting at the same time as or before or after the punching of the insulating substrate using a punching press. In addition, the recess 14 can be formed by irradiating the surface of the insulating substrate with laser light.
The cross-sectional shape of the recess 14 is not particularly limited, and may have various cross-sections such as a rectangle, a mortar shape, and a semicircular shape, and further, the edge of the recess 14 is chamfered or rounded. Also good.
Further, when a printed circuit board having a laminated structure is used as the diaphragm 10, lamination is performed after a hole penetrating the insulator layer is provided in advance in some of the insulator layers to be laminated. Alternatively, after the printed circuit board having the laminated structure is formed, a hole penetrating the part of the insulator layer may be formed by etching or cutting.

また、上記振動板１０と圧電素子３０との接着に用いる接着剤１６としては、非導電性の接着剤が好ましく、ＵＶ硬化型嫌気性接着剤が好ましい。 The adhesive 16 used for bonding the diaphragm 10 and the piezoelectric element 30 is preferably a non-conductive adhesive, and is preferably a UV curable anaerobic adhesive.

次に、本発明の第１の実施形態の振動板１３の製造プロセスの一例について、図３を参照しながら説明する。
まず、厚み５０μｍのＰＥＴフィルムを直径２０ｍｍの円板の一部に外周に向けて延出された凸部１２Ａを有する形状に打ち抜きプレスで打ち抜き加工を施すと同時に、前記ＰＥＴフィルムの主面の電極１５が形成される領域１３内の該領域１３の縁部近傍に、加圧ピンの押し込みにより、幅１ｍｍ、深さ８μｍで平面視形状がＤ字状の帯状の凹部１４を形成して、図１に示される絶縁基板１２を得る。
次に、図２に示されるように、得られた絶縁基板１２の主面上に、Ａｇ粉末を含有するポリマー性導電性ペーストを印刷膜厚の少なくとも一部が前記凹部１４に収容されるようにスクリーン印刷により塗布し、１００℃で１０分間乾燥した後、得られた絶縁基板１２の他方の主面に前記と同様に導電性樹脂ペーストを塗布し、１００℃で１０分間乾燥し、その後、１５０℃で１０分間加熱硬化して、前記絶縁基板１２の表裏にそれぞれ一対の引き出し導体１５を有する振動板１０を得る。Next, an example of a manufacturing process of the diaphragm 13 according to the first embodiment of the present invention will be described with reference to FIG.
First, a PET film having a thickness of 50 μm is punched by a punching press into a shape having a convex portion 12A extending toward the outer periphery of a part of a disk having a diameter of 20 mm, and at the same time, an electrode on the main surface of the PET film A band-shaped recess 14 having a width of 1 mm, a depth of 8 μm, and a D-shape in plan view is formed in the vicinity of the edge of the region 13 in the region 13 where 15 is formed by pressing the pressure pin. 1 is obtained.
Next, as shown in FIG. 2, a polymer conductive paste containing Ag powder is placed on the main surface of the obtained insulating substrate 12 so that at least a part of the printed film thickness is accommodated in the recess 14. After applying by screen printing and drying at 100 ° C. for 10 minutes, a conductive resin paste is applied to the other main surface of the obtained insulating substrate 12 in the same manner as described above, followed by drying at 100 ° C. for 10 minutes. The diaphragm 10 having a pair of lead conductors 15 on the front and back sides of the insulating substrate 12 is obtained by heating and curing at 150 ° C. for 10 minutes.

以上のように本実施形態の振動板１０は、上記（１）の構成を有するので、前記電極１５の印刷膜の縁部近傍の盛り上がりの少なくとも一部の発生が抑制され、圧電素子の貼り合わせに用いる接着剤１６のせき止めが防止され、前記電極１５の印刷膜の盛り上がりの生じていない部分から外側に圧し広げられるので、振動板１０と圧電素子３０との接着ミスや圧電素子３０の電極２９と振動板１０の電極１５との接続不良の発生を防止することができる。 As described above, since the diaphragm 10 of the present embodiment has the configuration (1), at least part of the bulge in the vicinity of the edge of the printed film of the electrode 15 is suppressed, and the piezoelectric element is bonded. Since the adhesive 16 used in the process is prevented from being dammed, and the printed film of the electrode 15 is pressed and spread outwardly, the bonding failure between the vibration plate 10 and the piezoelectric element 30 or the electrode 29 of the piezoelectric element 30 is prevented. And poor connection between the electrodes 10 of the diaphragm 10 can be prevented.

また、本実施形態の振動板１０は、上記（１）に加えて、（２）の構成を有するので、前記電極１５の印刷膜の縁部近傍の盛り上がりの発生が防止され、接着剤１６が均一に濡れ広がることができるので、所定の厚みの圧電振動板を安定して取得することができ、例えば音圧バラツキ等が低減できる。 Further, since the diaphragm 10 of the present embodiment has the configuration of (2) in addition to the above (1), the occurrence of swell in the vicinity of the edge of the printed film of the electrode 15 is prevented, and the adhesive 16 Since it can spread evenly and uniformly, a piezoelectric diaphragm having a predetermined thickness can be obtained stably, for example, variation in sound pressure can be reduced.

次に、本発明の振動板の第２の実施形態について、図５〜図７を参照して説明する。
図５は第２の実施形態の振動板４０に用いる絶縁基板４２の全体構造を示す図である。図５（Ｇ）は前記絶縁基板４２の平面図であり、図５（Ｈ）は前記絶縁基板４２の上記図５（Ｇ）におけるＨ−Ｈ線の厚み方向を拡大した断面図である。図６は本実施形態の振動板４０の全体構造を示す図である。図６（Ｉ）は前記振動板４０の平面図であり、図６（Ｊ）は前記振動板４０の上記図６（Ｉ）におけるＪ−Ｊ線の厚み方向を拡大した断面図である。図７は本実施形態の振動板４０に圧電素子６０を貼り合わせた状態の圧電振動板５０の内部構造を示す厚み方向を拡大した断面図である。Next, a second embodiment of the diaphragm of the present invention will be described with reference to FIGS.
FIG. 5 is a view showing the entire structure of the insulating substrate 42 used in the diaphragm 40 of the second embodiment. FIG. 5G is a plan view of the insulating substrate 42, and FIG. 5H is a sectional view of the insulating substrate 42 in which the thickness direction of the HH line in FIG. 5G is enlarged. FIG. 6 is a diagram showing the overall structure of the diaphragm 40 of the present embodiment. 6 (I) is a plan view of the diaphragm 40, and FIG. 6 (J) is a cross-sectional view of the diaphragm 40 in which the thickness direction of the JJ line in FIG. 6 (I) is enlarged. FIG. 7 is an enlarged cross-sectional view showing the internal structure of the piezoelectric diaphragm 50 in a state where the piezoelectric element 60 is bonded to the diaphragm 40 of the present embodiment.

本実施形態の振動板４０と先の第１の実施形態の振動板１０とで異なる点は二つあり、その第１は、先の第１の実施形態では前記絶縁基板１２に形成される凹部１４は電極１５が形成される領域１３内の縁部近傍に帯状に連続して形成されているのに対し、本第２の実施形態においては、凹部４４は電極４５が形成される領域４３内の縁部近傍に該領域の縁部に沿って互いに離間して短冊状に複数形成されている点にある。
その第２は、先の第１の実施形態では前記絶縁基板１２に形成される帯状の凹部１４が幅方向で均一な深さを有するのに対し、本第２の実施形態においては、複数の短冊状の凹部４４のそれぞれが、該凹部４４の幅の中央付近で深く周辺で浅くなって幅方向の断面が所謂すり鉢状に形成されている点にある。There are two differences between the diaphragm 40 of the present embodiment and the diaphragm 10 of the previous first embodiment, the first being a recess formed in the insulating substrate 12 in the previous first embodiment. 14 is formed continuously in the vicinity of the edge in the region 13 in which the electrode 15 is formed, whereas in the second embodiment, the recess 44 is in the region 43 in which the electrode 45 is formed. A plurality of strips are formed in the vicinity of the edge of the region so as to be separated from each other along the edge of the region.
Second, in the first embodiment, the strip-shaped recess 14 formed in the insulating substrate 12 has a uniform depth in the width direction, whereas in the second embodiment, a plurality of Each of the strip-shaped concave portions 44 is deep in the vicinity of the center of the width of the concave portion 44 and shallow in the periphery, and the cross section in the width direction is formed in a so-called mortar shape.

本発明の振動板の第２の実施形態に用いる絶縁基板４２は、図５に示すように、略円板状の絶縁基板４２には外周方向に延出された凸部４２Ａが形成されている。また、該絶縁基板４２の両主面には、一点鎖線で囲まれるように、円板状の圧電素子６０の電極５９と接続するための電極４５が形成される領域４３がそれぞれ一対設けられている。前記電極４５が形成される領域４３内にはそれぞれ、該領域４３の縁部近傍に該縁部に沿って複数の凹部４４が短冊状に形成されている。そして、図６に示すように、前記凹部４４に重なるように膜状の電極４５が印刷形成されている。 As shown in FIG. 5, the insulating substrate 42 used in the second embodiment of the diaphragm of the present invention is formed with a convex portion 42 A extending in the outer circumferential direction on the substantially disc-shaped insulating substrate 42. . In addition, a pair of regions 43 in which electrodes 45 for connection to the electrodes 59 of the disk-shaped piezoelectric element 60 are formed are provided on both main surfaces of the insulating substrate 42 so as to be surrounded by a one-dot chain line. Yes. In each of the regions 43 where the electrodes 45 are formed, a plurality of concave portions 44 are formed in a strip shape in the vicinity of the edge of the region 43 along the edge. As shown in FIG. 6, a film-like electrode 45 is printed and formed so as to overlap the concave portion 44.

具体的には、円板状の圧電素子６０を貼着するための略円板状の絶縁基板４２と、前記圧電素子６０の電極５９と接続するために前記絶縁基板４２の少なくとも一方の主面上に形成された膜状の電極４５と、を有する振動板４０において、前記絶縁基板４２の主面の前記電極４５が形成される領域４３内の該領域４３の縁部近傍に該縁部に沿って予め複数の短冊状の凹部４４が形成されており、前記電極４５の縁部近傍の膜厚の少なくとも一部が前記凹部４４内に収容されているものである。 Specifically, a substantially disk-shaped insulating substrate 42 for attaching the disk-shaped piezoelectric element 60 and at least one main surface of the insulating substrate 42 for connection to the electrode 59 of the piezoelectric element 60. In the diaphragm 40 having the film-like electrode 45 formed thereon, the edge of the main surface of the insulating substrate 42 near the edge of the region 43 in the region 43 where the electrode 45 is formed. A plurality of strip-shaped recesses 44 are formed in advance, and at least a part of the film thickness in the vicinity of the edge of the electrode 45 is accommodated in the recess 44.

また、上記第２の実施形態は、前記凹部４４が前記領域４３の縁部に沿って互いに離間して複数形成されているものである。 In the second embodiment, a plurality of the recesses 44 are formed apart from each other along the edge of the region 43.

より具体的には、略円板状の絶縁基板４２には、上述したように、外周方向に延出された凸部４２Ａが形成されており、該絶縁基板４２の両主面には、円板状の圧電素子６０の一対の半円形の電極５９と接続するための一点鎖線で示される略半円形をした電極４５が形成される領域４３がそれぞれ線対称に一対設けられている。前記形成される領域４３内にはそれぞれ、該領域４３の縁部近傍に予め該縁部に沿って複数の凹部４４が平面視形状が略Ｄ字形で互いに離間して短冊状に形成されている。そして、図６に示すように、前記絶縁基板４２の両主面に前記凹部４４に重なるように、電極４５がそれぞれ印刷により膜状に形成されるとともに、該電極４５の縁部近傍の膜厚の少なくとも一部が前記凹部４４内に収容されている。また、前記絶縁基板４２の外周方向に延出された凸部４２Ａには、前記一対の電極４５からそれぞれ引き出し部４５Ａが延出されている。 More specifically, as described above, the substantially disc-shaped insulating substrate 42 is formed with convex portions 42A extending in the outer peripheral direction, and the main surfaces of the insulating substrate 42 are circular. A pair of regions 43 each having a substantially semicircular electrode 45 indicated by a one-dot chain line for connection to a pair of semicircular electrodes 59 of the plate-like piezoelectric element 60 are provided in line symmetry. In each of the regions 43 to be formed, a plurality of recesses 44 are formed in advance in the vicinity of the edge of the region 43 along the edge so as to be in a strip shape with a substantially D shape in plan view. . Then, as shown in FIG. 6, the electrodes 45 are formed in a film shape by printing so as to overlap the concave portions 44 on both main surfaces of the insulating substrate 42, and the film thickness in the vicinity of the edge of the electrode 45. At least a portion thereof is accommodated in the recess 44. In addition, lead portions 45 A are extended from the pair of electrodes 45 to the convex portions 42 A extending in the outer peripheral direction of the insulating substrate 42.

本実施形態の振動板４０は、上述のように形成されているので、電極４５の印刷膜厚の縁部近傍の盛り上がりの少なくとも一部の発生が抑制され接着剤４６のせき止めを防止することが出来るとともに、前記凹部４４の形成に伴って前記振動板４０の前記領域４３の縁部近傍で該振動板４０の強度が局部的に低下するのを抑制することができる。 Since the diaphragm 40 of the present embodiment is formed as described above, the occurrence of at least a part of the bulge in the vicinity of the edge of the printed film thickness of the electrode 45 is suppressed, and the adhesive 46 can be prevented from being blocked. In addition, the strength of the diaphragm 40 can be suppressed from being locally reduced in the vicinity of the edge of the region 43 of the diaphragm 40 with the formation of the recess 44.

次に、前記第２の実施形態の振動板４０を用いた圧電振動板５０は、図７に示すように、振動板４０の両主面に、圧電体層５８と一対の電極５９とが交互に積層された圧電素子６０がそれぞれエポキシ系の絶縁性の接着剤４６を用いて接着され、前記振動板４０の電極４５と前記圧電素子６０の電極５９とが導電接続されている。
このとき、塗布された接着剤４６は、前記振動板４０の電極４５の印刷膜の縁部近傍の少なくとも一部に盛り上がりがないので、接着剤４６がせき止められることがなく、前記電極４５と前記圧電素子６０の電極５９とで圧し拡げられて、前記電極４５の縁部の外側まで濡れ拡がっている。このため、振動板４０の電極４５の表面の微細な凹凸と前記圧電素子６０の電極５９の表面の微細な凹凸とが相互に接触して導電接続されている。Next, in the piezoelectric diaphragm 50 using the diaphragm 40 of the second embodiment, as shown in FIG. 7, the piezoelectric layers 58 and the pair of electrodes 59 are alternately formed on both main surfaces of the diaphragm 40. The piezoelectric elements 60 stacked on each other are bonded using an epoxy insulating adhesive 46, and the electrode 45 of the diaphragm 40 and the electrode 59 of the piezoelectric element 60 are conductively connected.
At this time, the applied adhesive 46 does not bulge at least in the vicinity of the edge of the printed film of the electrode 45 of the vibration plate 40, so that the adhesive 46 is not blocked and the electrode 45 and the The piezoelectric element 60 is pressed and expanded with the electrode 59 and spreads out to the outside of the edge of the electrode 45. For this reason, the fine irregularities on the surface of the electrode 45 of the diaphragm 40 and the fine irregularities on the surface of the electrode 59 of the piezoelectric element 60 are in contact with each other and conductively connected.

以上のように本実施形態の振動板４０は、上記（１）の構成を有するので、前記電極４５の印刷膜の縁部近傍の盛り上がりの少なくとも一部の発生が抑制され、該振動板４０に圧電素子６０を貼り合わせる際に用いる接着剤４６はせき止めが防止され、前記電極４５の印刷膜の盛り上がりの生じていない部分から外側に圧し広げられるので、振動板４０と圧電素子６０との接着ミスや圧電素子６０の電極５９と振動板４０の電極４５との接続不良の発生を防止することができる。 As described above, since the diaphragm 40 of the present embodiment has the configuration (1), at least part of the bulge in the vicinity of the edge of the printed film of the electrode 45 is suppressed, and the diaphragm 40 The adhesive 46 used for bonding the piezoelectric element 60 is prevented from being damped, and is pressed outward from a portion of the printed film of the electrode 45 where the bulge does not occur, so that the bonding error between the diaphragm 40 and the piezoelectric element 60 is incorrect. In addition, it is possible to prevent the occurrence of poor connection between the electrode 59 of the piezoelectric element 60 and the electrode 45 of the diaphragm 40.

また、本実施形態の振動板４０は、上記（１）に加えて、（３）の構成を有するので、前記電極４５の印刷膜の縁部近傍の少なくとも一部の盛り上がりの発生が防止され、接着剤４６がせき止めを防止することができるとともに、前記凹部４４の形成に伴って前記振動板４０の強度が局部的に低下するのを抑制することができる。 In addition to the above (1), the diaphragm 40 of the present embodiment has the configuration of (3), so that at least part of the bulge in the vicinity of the edge of the printed film of the electrode 45 is prevented, The adhesive 46 can prevent the clogging, and can suppress the strength of the diaphragm 40 from being locally reduced with the formation of the recess 44.

次に、本発明の振動板の第３の実施形態について、図８〜図１１を参照して説明する。図８は第３の実施形態の振動板７０に用いる絶縁基板７２の全体構造を示す図である。図８（Ｋ）は前記絶縁基板７２の平面図であり、図８（Ｌ）は前記絶縁基板７２の上記図８（Ｋ）におけるＬ−Ｌ線の厚み方向を拡大した断面図である。図９は本実施形態の振動板７０の全体構造を示す図である。図９（Ｍ）は前記振動板７０の平面図であり、図９（Ｎ）は前記振動板７０の上記図９（Ｍ）におけるＮ−Ｎ線の厚み方向を拡大した断面図である。図１０は本実施形態の振動板７０に圧電素子９０を貼り合わせた状態の圧電振動板８０の外観を示す斜視図であり、図１１は前記圧電振動板８０の上記図１０におけるＰ−Ｐ線の厚み方向を拡大した断面図である。 Next, a third embodiment of the diaphragm of the present invention will be described with reference to FIGS. FIG. 8 is a diagram showing the overall structure of the insulating substrate 72 used in the diaphragm 70 of the third embodiment. 8K is a plan view of the insulating substrate 72, and FIG. 8L is a cross-sectional view of the insulating substrate 72 in which the thickness direction of the line LL in FIG. 8K is enlarged. FIG. 9 is a diagram showing the overall structure of the diaphragm 70 of the present embodiment. FIG. 9M is a plan view of the diaphragm 70, and FIG. 9N is a cross-sectional view in which the thickness direction of the line NN in FIG. 9M of the diaphragm 70 is enlarged. 10 is a perspective view showing an appearance of the piezoelectric diaphragm 80 in a state where the piezoelectric element 90 is bonded to the diaphragm 70 of the present embodiment, and FIG. 11 is a P-P line of the piezoelectric diaphragm 80 in FIG. It is sectional drawing to which the thickness direction of was expanded.

本実施形態の振動板７０と先の第２の実施形態の振動板４０とで異なる点は３つあり、その第１は、先の第２の実施形態では振動板４０に用いる絶縁基板４２が単層の絶縁基板として構成されるとともに該絶縁基板４２に凹部４４が窪みとして形成されているのに対し、本第３の実施形態においては、振動板７０に用いる絶縁基板７２が複数の絶縁体層７８（具体的には５つの絶縁体層７８）を備えた積層体からなり、前記５つの絶縁体層７８のうちの最上層の１層目の絶縁体層７８と最下層の５層目の絶縁体層７８にそれぞれ貫通孔が設けられ、凹部７４は前記絶縁体層７８の貫通孔により形成されたものである点にある。
その第２は、本実施形態においては、前記絶縁基板７２を構成する５つの絶縁体層７８のうちの最上層の１層目の絶縁体層７８と２層目の絶縁体層７８との間、および４層目の絶縁体層７８と最下層の５層目の絶縁体層７８との間にそれぞれ内部導体層７７が設けられており、前記凹部７４の底面に前記内部導体層７７が露出している点にある。
その第３は、先の第１及び第２の実施形態では略円板状の絶縁基板の凸部の表面に電極の引き出し部が前記電極から延出されているのに対し、本第３の実施形態においては、絶縁基板７２の凸部７２Ａの絶縁体層７８の層間に引き出し部７７Ａが前記内部導体層７７から延出されており前記絶縁基板７２の凸部７２Ａの前記５つの絶縁体層７８のうちの１層目の絶縁体層７８と５層目の絶縁体層７８にはそれぞれ切欠きが設けられて前記内部導体層７７の引き出し部７７Ａがそれぞれ露出されている点にある。There are three differences between the diaphragm 70 of the present embodiment and the diaphragm 40 of the previous second embodiment. The first is that the insulating substrate 42 used for the diaphragm 40 in the second embodiment is the same. In the third embodiment, the insulating substrate 72 used for the vibration plate 70 includes a plurality of insulators, whereas the insulating substrate 42 is configured as a single-layer insulating substrate and the recess 44 is formed as a depression. A layered body including a layer 78 (specifically, five insulator layers 78), and among the five insulator layers 78, the uppermost first insulator layer 78 and the lowermost fifth layer. Each of the insulating layers 78 is provided with a through hole, and the recess 74 is formed by the through hole of the insulating layer 78.
Second, in the present embodiment, the insulating layer 78 between the uppermost first insulating layer 78 and the second insulating layer 78 among the five insulating layers 78 constituting the insulating substrate 72. And an inner conductor layer 77 is provided between the fourth insulator layer 78 and the lowermost insulator layer 78, and the inner conductor layer 77 is exposed on the bottom surface of the recess 74. It is in the point.
The third is that, in the first and second embodiments, the lead-out portion of the electrode extends from the electrode on the surface of the convex portion of the substantially disc-shaped insulating substrate, whereas the third embodiment In the embodiment, a lead portion 77A extends from the inner conductor layer 77 between the insulating layers 78 of the convex portions 72A of the insulating substrate 72, and the five insulating layers of the convex portions 72A of the insulating substrate 72 are provided. The first insulator layer 78 and the fifth insulator layer 78 out of 78 are provided with notches so that the lead portions 77A of the internal conductor layer 77 are exposed.

本発明の振動板の第３の実施形態は、前記絶縁基板７２は複数の絶縁体層７８と内部導体層７７とを積層してなる略円形の可撓性の絶縁基板７２の両主面に貫通孔からなる複数の凹部７４が平面視形状が略Ｄ字形になるように短冊状に配列されて線対称に形成され、前記凹部７４に重なるように略半円形の電極７５が印刷形成されているものである。また、前記絶縁基板７２の外周方向に延出された凸部７２Ａには、前記複数の絶縁体層７８のうち一部の絶縁体層７８に設けた切欠きから前記内部導体層７７から延出された引き出し部７７Ａが露出されている。 In the third embodiment of the diaphragm of the present invention, the insulating substrate 72 is formed on both main surfaces of a substantially circular flexible insulating substrate 72 formed by laminating a plurality of insulator layers 78 and an internal conductor layer 77. A plurality of recesses 74 made of through-holes are arranged in a strip shape so as to have a substantially D shape in plan view, are formed in line symmetry, and a substantially semicircular electrode 75 is printed and formed so as to overlap the recesses 74. It is what. Further, the convex portion 72A extending in the outer peripheral direction of the insulating substrate 72 extends from the inner conductor layer 77 from a notch provided in a part of the insulating layers 78 of the plurality of insulating layers 78. The drawn-out portion 77A is exposed.

具体的には、図８に示されるように、前記絶縁基板７２が複数の絶縁体層７８と内部導体層７７とを積層してなる可撓性の絶縁基板７２の両主面の電極７５が形成される領域７３内の該領域７３の縁部近傍に前記領域７３の縁部に沿って貫通孔からなる複数の凹部７４が互いに離間して短冊状に複数配置されるように形成され、図９に示されるように電極７５の印刷膜厚の少なくとも一部が前記凹部７４に収容されるように前記絶縁基板７２の両主面上にそれぞれ電極７５が形成され、前記絶縁体層７８に形成された貫通孔からなる凹部７４の底面には前記内部導体層７７の一部が露出されている。また、前記１層目と２層目の層間の内部導体層７７と、前記４層目と５層目の層間の内部導体層７７とが、２層目〜４層目の絶縁体層７８に設けたスルーホールに充填されたスルーホール導体７１を通じて互いに接続されている。
このため、電極７５の印刷膜厚の縁部近傍の盛り上がりに相当する部分が断続的に前記凹部７４に吸収されて、前記凹部７４上では前記印刷膜の他の領域と同様の厚みに形成されるとともに、前記電極７５と前記内部導体層７７とが接続されている。Specifically, as shown in FIG. 8, the electrodes 75 on both main surfaces of a flexible insulating substrate 72 in which the insulating substrate 72 is formed by laminating a plurality of insulator layers 78 and internal conductor layers 77 are provided. In the region 73 to be formed, in the vicinity of the edge of the region 73, a plurality of recesses 74 made of through holes are formed along the edge of the region 73 so as to be spaced apart from each other and arranged in a strip shape. As shown in FIG. 9, the electrodes 75 are formed on both main surfaces of the insulating substrate 72 so that at least a part of the printed film thickness of the electrodes 75 is accommodated in the recesses 74, and formed on the insulator layer 78. A part of the inner conductor layer 77 is exposed on the bottom surface of the concave portion 74 formed of the through hole. Further, the inner conductor layer 77 between the first and second layers and the inner conductor layer 77 between the fourth and fifth layers are formed as the second to fourth insulating layers 78. They are connected to each other through through-hole conductors 71 filled in the provided through-holes.
For this reason, the portion corresponding to the bulge in the vicinity of the edge of the printed film thickness of the electrode 75 is intermittently absorbed by the concave portion 74 and formed on the concave portion 74 to the same thickness as other regions of the printed film. In addition, the electrode 75 and the inner conductor layer 77 are connected.

次に、前記第３の実施形態の振動板７０を用いた圧電振動板８０は、図１０及び図１１に示すように、振動板７０の両主面に、圧電体層８８と一対の電極８９とが交互に積層された圧電素子９０がそれぞれエポキシ系の絶縁性の接着剤７６を用いて接着され、前記振動板７０の電極７５と前記圧電素子９０の電極８９とが導電接続されている。
このとき、塗布された接着剤７６は、前記振動板７０の印刷膜の縁部近傍に盛り上がりがないので、接着剤がせき止められることがなく、前記電極７５と前記圧電素子９０の電極８９とで圧し拡げられて、前記電極７５の縁部の外側まで濡れ拡がっている。このため、振動板７０の電極８５の表面の微細な凹凸と前記圧電素子９０の電極８９の表面の微細な凹凸とが相互に接触して導電接続されている。Next, the piezoelectric diaphragm 80 using the diaphragm 70 of the third embodiment has a piezoelectric layer 88 and a pair of electrodes 89 on both main surfaces of the diaphragm 70 as shown in FIGS. Are bonded using epoxy insulating adhesive 76, and electrode 75 of diaphragm 70 and electrode 89 of piezoelectric element 90 are conductively connected.
At this time, since the applied adhesive 76 does not rise near the edge of the printed film of the vibration plate 70, the adhesive is not blocked, and the electrode 75 and the electrode 89 of the piezoelectric element 90 The pressure is expanded and wetted to the outside of the edge of the electrode 75. For this reason, the fine irregularities on the surface of the electrode 85 of the vibration plate 70 and the fine irregularities on the surface of the electrode 89 of the piezoelectric element 90 are in contact with each other and are conductively connected.

以上のように本実施形態の振動板７０は、上記（１）の構成を有するので、前記電極の印刷膜の縁部近傍の盛り上がりの少なくとも一部の発生が抑制され、圧電素子の貼り合わせに用いる接着剤の前記盛り上がりによるせき止めが防止されるので、振動板と圧電素子との接着ミスや圧電素子の電極と振動板の電極との接続不良の発生を防止することができる。 As described above, since the diaphragm 70 of the present embodiment has the configuration (1), at least a part of the bulge in the vicinity of the edge of the printed film of the electrode is suppressed, and the piezoelectric element is bonded. Since the clogging due to the swell of the adhesive to be used is prevented, it is possible to prevent the bonding error between the diaphragm and the piezoelectric element and the occurrence of poor connection between the electrode of the piezoelectric element and the electrode of the diaphragm.

また、本実施形態の振動板７０は、上記（１）に加えて（４）の構成を有するので、前記凹部に前記膜状の電極の膜厚の一部が所定の厚み寸法で充填され、振動板の一方の主面上の電極の膜厚が均一となる。
また、本実施形態の振動板７０は、上記（１）、（４）に加えて（５）の構成を有するので、振動板の表面の電極の配置に関わらず任意の方向に引き出しを行うことができる。Further, since the diaphragm 70 of the present embodiment has the configuration of (4) in addition to the above (1), a part of the film thickness of the film-like electrode is filled in the concave portion with a predetermined thickness dimension, The film thickness of the electrode on one main surface of the diaphragm is uniform.
Further, since the diaphragm 70 of the present embodiment has the configuration (5) in addition to the above (1) and (4), the diaphragm 70 can be pulled out in any direction regardless of the arrangement of the electrodes on the surface of the diaphragm. Can do.

なお、上記第１〜第３の実施形態では、圧電型電気音響変換器の一例として圧電型スピーカに好適な振動板の実施例を示したが、本発明は、これに限定するものではなく、圧電レシーバ、圧電サウンダ、圧電マイクロホンなどの各種の圧電型電気音響変換器の振動板に適用することができる。また、これらの圧電型電気音響変換器は、公知の各種の電子機器に適用することができる。 In the first to third embodiments, examples of the diaphragm suitable for the piezoelectric speaker are shown as an example of the piezoelectric electroacoustic transducer, but the present invention is not limited to this. The present invention can be applied to diaphragms of various piezoelectric electroacoustic transducers such as piezoelectric receivers, piezoelectric sounders, and piezoelectric microphones. Moreover, these piezoelectric electroacoustic transducers can be applied to various known electronic devices.

本発明によれば、薄型化が要求される電子機器用の圧電型電気音響変換器の振動板に好適である。 The present invention is suitable for a diaphragm of a piezoelectric electroacoustic transducer for electronic equipment that is required to be thin.

本発明の第１の実施形態の振動板に用いる絶縁基板を示す図である。It is a figure which shows the insulated substrate used for the diaphragm of the 1st Embodiment of this invention. 前記第１の実施形態の振動板を示す図である。It is a figure which shows the diaphragm of the said 1st Embodiment. 前記第１の実施形態の振動板に圧電素子を張り合わせた状態を示す外観斜視図である。It is an external appearance perspective view which shows the state which bonded the piezoelectric element to the diaphragm of the said 1st Embodiment. 前記第１の実施形態の振動板に圧電素子を張り合わせた状態の内部構造を示す厚み方向を拡大した断面図である。It is sectional drawing which expanded the thickness direction which shows the internal structure of the state which bonded the piezoelectric element to the diaphragm of the said 1st Embodiment. 本発明の第２の実施形態の振動板に用いる絶縁基板を示す図である。It is a figure which shows the insulated substrate used for the diaphragm of the 2nd Embodiment of this invention. 前記第２の実施形態の振動板を示す図である。It is a figure which shows the diaphragm of the said 2nd Embodiment. 前記第２の実施形態の振動板に圧電素子を張り合わせた状態の内部構造を示す厚み方向を拡大した断面図である。It is sectional drawing which expanded the thickness direction which shows the internal structure of the state which bonded the piezoelectric element to the diaphragm of the said 2nd Embodiment. 本発明の第３の実施形態の振動板に用いる絶縁基板を示す図である。It is a figure which shows the insulated substrate used for the diaphragm of the 3rd Embodiment of this invention. 前記第３の実施形態の振動板を示す図である。It is a figure which shows the diaphragm of the said 3rd Embodiment. 前記第３の実施形態の振動板に圧電素子を張り合わせた状態を示す外観斜視図である。It is an external appearance perspective view which shows the state which bonded the piezoelectric element to the diaphragm of the said 3rd Embodiment. 前記第３の実施形態の振動板に圧電素子を張り合わせた状態の内部構造を示す厚み方向を拡大した断面図である。It is sectional drawing which expanded the thickness direction which shows the internal structure of the state which bonded the piezoelectric element to the diaphragm of the said 3rd Embodiment. 背景技術の振動板を示す図である。It is a figure which shows the diaphragm of background art. 前記背景技術の振動板に圧電素子を張り合わせた状態を示す外観斜視図である。It is an external appearance perspective view which shows the state which bonded the piezoelectric element to the diaphragm of the said background art. 前記背景技術の振動板の内部構造を示す厚み方向を拡大した断面図である。It is sectional drawing to which the thickness direction which shows the internal structure of the diaphragm of the said background art was expanded.

符号の説明Explanation of symbols

１０：振動板
１２：絶縁基板
１２Ａ：凸部
１３：電極が形成される領域
１４：凹部
１５：電極
１５Ａ：引き出し部
１６：接着剤
２０：圧電振動板
２８：圧電体層
２９：電極
３０：圧電素子
４０：振動板
４２：絶縁基板
４２Ａ：凸部
４３：電極が形成される領域
４４：凹部
４５：電極
４５Ａ：引き出し部
４６：接着剤
５０：圧電振動板
５８：圧電体層
５９：電極
６０：圧電素子
７０：振動板
７２：絶縁基板
７２Ａ：凸部
７３：電極が形成される領域
７４：凹部
７５：電極
７６：接着剤
７７：内部導体層
７７Ａ：引き出し部
７８：絶縁体層
８０：圧電振動板
８８：圧電体層
８９：電極
９０：圧電素子10: Diaphragm 12: Insulating substrate 12A: Convex portion 13: Electrode forming region 14: Concavity 15: Electrode 15A: Leading portion 16: Adhesive 20: Piezoelectric vibration plate 28: Piezoelectric layer 29: Electrode 30: Piezoelectric Element 40: Diaphragm 42: Insulating substrate 42A: Convex part 43: Area 44 where electrode is formed: Concave part 45: Electrode 45A: Lead part 46: Adhesive 50: Piezoelectric diaphragm 58: Piezoelectric layer 59: Electrode 60: Piezoelectric element 70: Diaphragm 72: Insulating substrate 72A: Protruding portion 73: Electrode forming region 74: Concavity 75: Electrode 76: Adhesive 77: Internal conductor layer 77A: Leading portion 78: Insulator layer 80: Piezoelectric vibration Plate 88: Piezoelectric layer 89: Electrode 90: Piezoelectric element

Claims

板状の圧電素子を貼着するための絶縁基板と、前記圧電素子の電極と接続するために前記絶縁基板の少なくとも一方の主面上に形成された膜状の電極と、を有する振動板において、
前記絶縁基板の主面の前記電極が形成される領域内の該領域の縁部近傍に予め凹部が形成されており、
前記電極の縁部近傍の膜厚の少なくとも一部が前記凹部内に収容されていることを特徴とする振動板。In a diaphragm having an insulating substrate for attaching a plate-like piezoelectric element, and a film-like electrode formed on at least one main surface of the insulating substrate to be connected to an electrode of the piezoelectric element ,
A recess is formed in advance in the vicinity of the edge of the region in the region where the electrode is formed on the main surface of the insulating substrate,
At least a part of the film thickness in the vicinity of the edge of the electrode is accommodated in the recess.

前記凹部が前記領域の縁部に沿って帯状に形成されていることを特徴とする請求項１記載の振動板。 The diaphragm according to claim 1, wherein the recess is formed in a strip shape along an edge of the region.

前記凹部が前記領域の縁部に沿って互いに離間して複数形成されていることを特徴とする請求項１記載の振動板。 The diaphragm according to claim 1, wherein a plurality of the recesses are formed apart from each other along an edge of the region.

前記絶縁基板が複数の絶縁体層を備えた積層体からなり、前記凹部が前記複数の絶縁体層のうちの少なくとも１つの絶縁体層に貫通孔が形成されたものであることを特徴とする請求項１〜３のいずれか１項に記載の振動板。 The insulating substrate is made of a laminated body including a plurality of insulator layers, and the concave portion has a through hole formed in at least one insulator layer of the plurality of insulator layers. The diaphragm according to any one of claims 1 to 3.

前記絶縁基板が複数の絶縁体層と該複数の絶縁体層の層間に配置された少なくとも１つの内部導体層との積層体からなり、前記絶縁体層に形成された貫通孔を介して前記電極と前記内部導体層とが接続されていることを特徴とする請求項４に記載の振動板。 The insulating substrate comprises a laminate of a plurality of insulator layers and at least one internal conductor layer disposed between the plurality of insulator layers, and the electrode is formed through a through hole formed in the insulator layer. The diaphragm according to claim 4, wherein the inner conductor layer is connected to the diaphragm.