JP3916321B2

JP3916321B2 - Electronic component unit and temperature compensated crystal oscillator

Info

Publication number: JP3916321B2
Application number: JP14854198A
Authority: JP
Inventors: 秀春中野; 祐浩羽柴
Original assignee: Hokuriku Electric Industry Co Ltd
Current assignee: Hokuriku Electric Industry Co Ltd
Priority date: 1998-05-29
Filing date: 1998-05-29
Publication date: 2007-05-16
Anticipated expiration: 2018-05-29
Also published as: JPH11340346A

Description

【０００１】
【発明の属する技術分野】
本発明は、温度補償型水晶発振器等の電子部品ユニットに関するものであり、より具体的には温度補償型水晶発振器に関するものである。
【０００２】
【従来の技術】
従来の温度補償型水晶発振器等の電子部品ユニットには、回路基板に対して金属製のカバー部材が取付けられた構造を有するものがある。このような電子部品ユニットで用いる回路基板の表面には、複数の表面実装電子部品が表面実装される表面側回路パターンが形成され、また裏面には表面側回路パターンと電気的に接続されたアースパターンと複数の端子電極とを含む裏面側回路パターンが形成されている。カバー部材は、複数の表面実装電子部品を覆うように形成されている。カバー部材を回路基板に対して取付けるために、回路基板の対向する一対の側面には一対の嵌合用凹部が形成されており、一対の嵌合用凹部の内面にはアースパターンと電気的に接続された半田付け電極がそれぞれ形成されている。またカバー部材には一対の嵌合用凹部に嵌合されて一対の半田付け電極に半田付け接続される一対の嵌合部が一体に設けられている。そしてカバー部材の一対の嵌合部が回路基板の一対の嵌合用凹部に嵌合された状態で、一対の嵌合部が一対の半田付け電極に半田付け接続されてカバー部材が回路基板に機械的に且つ電気的に接続されている。一対の嵌合部の一対の半田付け電極への半田付け接続は、予め一対の嵌合部と一対の半田付け電極の接合部の上にいわゆるクリーム半田を塗布しておき、一対の嵌合部を回路基板の一対の嵌合用凹部に嵌合した後に、クリーム半田に光ビームを照射してクリーム半田を溶融させることにより行う。
【０００３】
【発明が解決しようとする課題】
従来のカバー部材に設けられた一対の嵌合部は、嵌合用凹部に嵌合されて半田付け電極と半田付け接続される１つの嵌合片を有していた。しかしながら従来の電子部品ユニットでは、嵌合片と半田付け電極との間に十分な量の溶融半田を止どめておくことができない場合があり、半田付け強度が十分に得られない場合があった。
【０００４】
本発明の目的は、カバー部材の半田付け作業が容易な電子部品ユニット及び温度補償型水晶発振器を提供することにある。
【０００５】
本発明の他の目的は、カバー部材の半田付け状態の確認が容易な電子部品ユニットを提供することにある。
【０００６】
本発明の他の目的は、カバー部材の位置決めが容易な電子部品ユニットを提供することにある。
【０００７】
本発明の更に他の目的は、カバー部材の半田付け作業が時間が短くて済む電子部品ユニットを提供することにある。
【０００８】
本発明の他の目的は、カバー部材の位置ずれと変形を阻止することができて、トリガブルチップ抵抗器のレーザトリミング作業を確実に行える温度補償型水晶発振器を提供することにある。
【０００９】
【課題を解決するための手段】
本発明が改良の対象とする温度補償型水晶発振器等の電子部品ユニットは、表面に表面側回路パターンが形成され且つ裏面に表面側回路パターンと電気的に接続されたアースパターンと複数の端子電極とを含む裏面側回路パターンが形成された回路基板と、回路基板の表面側回路パターン上に実装された複数の表面実装電子部品と、回路基板の表面上の複数の表面実装電子部品を覆うように形成されて回路基板に対して取付けられた金属製のカバー部材とを具備している。回路基板の対向する一対の側面には一対の嵌合用凹部が形成されている。また一対の嵌合用凹部の内面にはアースパターンと電気的に接続された半田付け電極がそれぞれ形成さている。さらにカバー部材には一対の嵌合用凹部に嵌合されて一対の半田付け電極に半田付け接続される一対の嵌合部が一体に設けられている。そしてカバー部材の一対の嵌合部が回路基板の一対の嵌合用凹部に嵌合された状態で、一対の嵌合部と一対の半田付け電極との間に配置された半田を介して一対の嵌合部が一対の半田付け電極に半田付け接続されてカバー部材が回路基板に機械的に且つ電気的に接続されている。温度補償型水晶発振器の場合には、回路基板の表面側回路パターン上に実装される複数の表面実装電子部品は、温度補償型水晶発振回路を構成する。
【００１０】
本発明においては、カバー部材の一対の嵌合部を、回路基板の側面に沿って形成した１以上の嵌合片により構成する。そして１以上の嵌合片には半田付け電極側に向かって突出する突出部をそれぞれ形成する。このような構造を採用すると、嵌合片と半田付け電極との上に塗布されて光ビームにより溶融した半田が突出部の周囲に回り込み、突出部の周囲に良好な半田フィレットを形成することができ、嵌合片と半田付け電極とを結合するに必要十分な量の半田を止どめることが可能になる。その結果、従来よりも半田付け強度が増大する。
【００１１】
特に、１以上の嵌合片が突出部を半田付け電極に向かって押し付けるバネ性を有していると、半田付け作業を開始する前に、カバー部材が所定の位置からずれたり浮き上がったりするのを防止することができる。そのため更にカバー部材の半田付け作業が容易になる。嵌合片の数が２以上になると、溶融半田が回り込む突出部の数も２以上になるため、良好な半田フィレットを２以上形成することができて、半田付け強度を更に高めることができる。
【００１２】
本発明によれば突出部の周囲に回り込んで形成された半田フィレットの形状から、半田付け状態を視覚により簡単に確認できるので、半田付けの検査が容易になる。
【００１３】
更に一対の嵌合部に回路基板の表面と接触する接触部を設け、また回路基板の一対の側面とは異なる他の一対の側面に更に別の一対の嵌合用凹部を形成し、更にカバー部材の一対の嵌合部が設けられた一対の側壁部とは異なる他の一対の側壁部に回路基板の別の一対の嵌合用凹部に嵌合される嵌合部と回路基板の表面と接触する接触部とを有する一対の嵌合接触片を一体に設けると、カバー部材を回路基板に対して正確に位置決めすることができる。特に、表面実装電子部品に周波数調整用にレーザトリミングが施されるトリマブルチップ抵抗器が含まれている温度補償型水晶発振器を製造する場合には、カバー部材にトリマブルチップ抵抗器を露出させる窓部が形成されることになる。そしてこの窓部を通してレーザトリミングが実施されることになる。この場合、カバー部材の取付姿勢が悪かったり、カバー部材が大きく撓んだ状態になると、窓部の位置及び形状が設計と異なってしまい、レーザトリミングに支障を与える可能性がある。しかしながら前述のような構造を採用すると、カバー部材を回路基板に対して正確に位置決めすることができ、またカバー部材の大きな変形も防止できるので、トリマブルチップ抵抗器のレーザトリミングをより確実に行える。
【００１４】
カバー部材を半田付けする場合に、熱は半田付け電極からアースパターンへと伝達される。この伝達される熱の量が多くなればなるほど、半田付け不良が発生する可能性が高くなる。そこで一対の半田付け電極とアースパターンとを電気的に接続する接続部の幅寸法を１ｍｍ以下にするのが好ましい。このようにすると半田付け電極からアースパターンに逃げる熱の量を大幅に制限することができて、短い時間で半田付け作業を終了することができて、半田付け不良が発生するのを防止できる。なお複数の電極のうちのアース電極もアースパターンと電気的に接続されるため、ユニットの各電極を半田付けにより表面実装する際の半田付け不良の発生を防止するために、アース電極とアースパターンとを接続する接続部の幅寸法も１ｍｍ以下にするのが好ましい。
【００１５】
【発明の実施の形態】
図１（Ａ）（Ｂ）〜図５は本発明を温度補償型水晶発振器からなる電子部品ユニットに適用した実施の形態の一例を示したもので、図１（Ａ）（Ｂ）は本例で用いている回路基板の平面図及び裏面図、図２は本例で用いているカバー部材の平面図、図３（Ａ）（Ｂ）は図２の左側面図及び右側面図、図４（Ａ）（Ｂ）は図２の正面図及び背面図、図５は本例で用いている嵌合片の構造を示す側面図、図６は本例の電子部品ユニットにおける回路基板とカバー部材の電気的，機械的接続部分の縦断面図である。
【００１６】
この電子部品ユニットは、図１（Ａ）（Ｂ）に示すように表面に表面側回路パターン１が形成され且つ裏面に表面側回路パターン１と電気的に接続されたアースパターン２と複数の端子電極３ａ〜３ｄとを含む裏面側回路パターン４が形成された長方形状の回路基板５と、該回路基板５の表面側回路パターン１上に実装されて温度補償型水晶発振回路を構成する複数の表面実装電子部品６，７ａ，７ｂ，…，８，９等と、回路基板５の表面上の複数の表面実装電子部品６，７ａ，７ｂ，…，８，９等を覆うように形成されて回路基板５に対して取付けられた図２〜図５に示す如き金属製のカバー部材１０とを具備している。
【００１７】
端子電極３ａ〜３ｄは回路基板５の周縁部に設けられ、これら端子電極３ａ〜３ｄの箇所で回路基板５の周縁部には、側面に開口する凹部３ad〜３ddが設けられ、これら凹部３ad〜３ddの内面にも端子電極３ａ〜３ｄが存在するようになっている。
【００１８】
表面実装電子部品６，７ａ，７ｂ，…，８，９等のうち、表面実装電子部品９は、周波数調整用にレーザトリミングが施されるトリマブルチップ抵抗器からなっている。
【００１９】
回路基板５の対向する一対の側面には、一対の嵌合用凹部１１ａ，１１ｂが形成されている。これら一対の嵌合用凹部１１ａ，１１ｂの内面には、アースパターン２と接続部１２ａ，１２ｂで電気的に接続された半田付け電極１３ａ，１３ｂがそれぞれ形成されている。各接続部１２ａ，１２ｂは、幅寸法が１ｍｍ以下に形成されている。
【００２０】
複数の端子電極３ａ〜３ｄのうちのアース電極３ｃもアースパターン２と接続部１２ｄにて電気的に接続されている。この場合の接続部１２ｄの幅寸法も１ｍｍ以下にするのが好ましい。
【００２１】
回路基板５の対向する他の一対の側面の中央には、一対の嵌合用凹部１１ｃ，１１ｄが形成されている。
【００２２】
カバー部材１０は、その上板部１０ｕが回路基板５の表面上を覆えるように長方形状をなしていて、この長方形状の上板部１０ｕの周縁部に長方形状の４つの側壁部１０ａ〜１０ｄが下向きに角筒状をなすように連設されている。角筒状をなす各側壁部１０ａ〜１０ｄは、回路基板５の上面周縁部に載れるような位置関係で上板部１０ｕに支持されている。
【００２３】
カバー部材１０の向かい合う一対の側壁部１０ａ，１０ｂの中央寄りの箇所の下部には、回路基板５の上面周縁部に載って接触する接触部１０as，１０bsを有する嵌合接触片１０a1，１０b1が設けられている。これら嵌合接触片１０a1，１０b1の下端には、回路基板５の一対の嵌合用凹部１１ａ，１１ｂに嵌合されて一対の半田付け電極１３ａ，１３ｂに半田付け接続される一対の嵌合部１４ａ，１４ｂが一体に設けられている。これら一対の嵌合部１４ａ，１４ｂは、回路基板５の側面に沿って間隔をあけて形成された２つの嵌合片１４a1，１４a2と２つの嵌合片１４b1，１４b2とにより構成されている。２つの嵌合片１４a1，１４a2の間の間隔と、２つの嵌合片１４b1，１４b2との間の間隔は、それぞれ視覚により半田付け状態を確認できる程度の寸法に設定されている。これら２つの嵌合片１４a1，１４a2と、２つの嵌合片１４b1，１４b2との先端側の各内向き面には、対応する半田付け電極１３ａ，１３ｂ側に向かって突出する突出部１５…がそれぞれ打ち出しにより図５に示すように形成されている。これら２つの嵌合片１４a1，１４a2と２つの嵌合片１４b1，１４b2は、各突出部１５…を回路基板５の半田付け電極１３ａ，１３ｂに向かって押し付けるバネ性を有している。
【００２４】
カバー部材１０の向かい合う一対の側壁部１０ａ，１０ｂとは異なる、他の向かい合う一対の側壁部１０ｃ，１０ｄの中央寄りの箇所の下部には、回路基板５の上面周縁部に載って接触する接触部１０cs，１０dsを有する嵌合接触片１０c1，１０d1が設けられている。これら嵌合接触片１０c1，１０d1の下端には、回路基板５の一対の側面に設けられた嵌合用凹部１１ａ，１１ｂとは異なる、他の一対の側面に設けられた向かい合う一対の嵌合用凹部１１ｃ，１１ｄに嵌合される一対の嵌合部１６ｃ，１６ｄが一体に設けられている。
【００２５】
カバー部材１０の上板部１０ｕには、周波数調整用にレーザトリミングが施されるトリマブルチップ抵抗器からなる表面実装電子部品９に対応する位置に該表面実装電子部品９を露出させる窓部１７が形成されている。この窓部１７は、カバー部材１０の１つの嵌合部１４ａに近接して形成されている。
【００２６】
このような電子部品ユニットにおいては、回路基板５の表面側回路パターン１側にカバー部材１０が図３（Ａ）（Ｂ）及び図４（Ａ）（Ｂ）に破線表示で示すように被せられる。この際に、カバー部材１０の各嵌合接触片１０a1，１０b1，１０c1，１０d1はその下端の接触部１０as，１０bs，１０cs，１０dsが回路基板５の上面の周縁部に接触状態で載る。この際に、嵌合接触片１０a1の先端に突設されている一対の嵌合片１４a1，１４a2は回路基板５の嵌合用凹部１１ａに嵌合されて、これら嵌合片１４a1，１４a2の先端側の各内向き面の各突出部１５が回路基板５の嵌合用凹部１１ａにおける半田付け電極１３ａにそれぞれ接触される。同様に、嵌合接触片１０b1の先端に突設されている一対の嵌合片１４b1，１４b2は回路基板５の嵌合用凹部１１ｂに嵌合されて、これら嵌合片１４b1，１４b2の先端側の各内向き面の各突出部１５が回路基板５の嵌合用凹部１１ｂにおける半田付け電極１３ｂにそれぞれ接触される。また、各嵌合接触片１０c1，１０d1の先端に突設されている嵌合部１６ｃ，１６ｄは、回路基板５の嵌合用凹部１１ｃ，１１ｄに嵌合される。
【００２７】
この状態で、裏返して回路基板５の裏面側を上向きにし、カバー部材１０の嵌合片１４a1，１４a2の先端側の各突出部１５が回路基板５の半田付け電極１３ａにそれぞれ接触している箇所の上面と、カバー部材１０の嵌合片１４b1，１４b2の先端側の各突出部１５が回路基板５の半田付け電極１３ｂにそれぞれ接触している箇所の上面とに、それぞれクリーム半田を所要量載せ、これらクリーム半田の箇所にレーザ等の光ビームを照射して該クリーム半田を完全に溶融させて、図６に示すようにカバー部材１０の嵌合片１４a1，１４a2の各突出部１５を回路基板５の半田付け電極１３ａに半田１８で接続し、カバー部材１０の嵌合片１４b1，１４b2の各突出部１５を回路基板５の半田付け電極１３ｂに半田１８で接続する。
【００２８】
このような電子部品ユニットを使用するに際しては、カバー部材１０の窓部１７を利用してトリマブルチップ抵抗器からなる表面実装電子部品９にレーザトリミングを施し、温度補償型水晶発振器からなる電子部品ユニットの周波数調整を行う。
【００２９】
本発明においては、カバー部材１０の一対の嵌合部１４ａ，１４ｂを、回路基板５の側面に沿って間隔をあけて形成した一対の嵌合片１４a1，１４a2、１４b1，１４b2により構成し、これら嵌合片１４a1，１４a2、１４b1，１４b2には対応する半田付け電極１３ａ，１３ｂ側に向かって突出する突出部１５…をそれぞれ形成したので、カバー部材１０の一対の嵌合部１４ａ，１４ｂと回路基板１０の嵌合用凹部１１ａ，１１ｂに設けた半田付け電極１３ａ，１３ｂとの間の接触面積が多くなって熱伝導性が大きくなり、しかも接触点が分散する。そのため、嵌合片１４a1，１４a2、１４b1，１４b2と半田付け電極１３ａ，１３ｂとの上に塗布されて光ビームにより溶融した半田１８が一対の嵌合部１１ａ，１１ｂの周囲に確実に回り込み、カバー部材１０の半田付け作業が容易になる。この場合、各一対の嵌合片１４a1，１４a2、１４b1，１４b2がその突出部１５…を半田付け電極１３ａ，１３ｂに向かって押し付けるバネ性を有していると、半田付け作業を開始する前に、カバー部材１０が所定の位置からずれたり浮き上がったりするのを防止することができる。そのため更にカバー部材１０の半田付け作業が容易になる。
【００３０】
更にこのカバー部材１０では、一対の嵌合部１４ａ，１４ｂの先端に回路基板５の表面と接触する接触部１４as，１４bsを設け、また回路基板５の一対の側面とは異なる他の一対の側面に更に別の一対の嵌合用凹部１１ｃ，１１ｄを形成し、更にカバー部材１０の一対の嵌合部１４ａ，１４ｂが設けられた一対の側壁部１０ａ，１０ｂとは異なる他の一対の側壁部１０ｃ，１０ｄに回路基板５の別の一対の嵌合用凹部１１ｃ，１１ｄに嵌合される嵌合部１６ｃ，１６ｄと回路基板５の表面と接触する接触部１４cs，１４dsとを有する一対の嵌合接触片１０c1，１０d1を一体に設けると、カバー部材１０を回路基板５に対して正確に位置決めすることができる。
【００３１】
特に、表面実装電子部品に周波数調整用にレーザトリミングが施されるトリマブルチップ抵抗器が含まれている温度補償型水晶発振器を製造する場合には、カバー部材１０にトリマブルチップ抵抗器を露出させる窓部９が形成されることになる。そしてこの窓部９を通してレーザトリミングが実施されることになる。この場合、カバー部材１０の取付姿勢が悪かったり、カバー部材１０が大きく撓んだ状態になると、窓部９の位置及び形状が設計と異なってしまい、レーザトリミングに支障を与える可能性がある。しかしながら前述のような構造を採用すると、カバー部材１０を回路基板５に対して正確に位置決めすることができ、またカバー部材１０の大きな変形も防止できるので、トリマブルチップ抵抗器のレーザトリミングをより確実に行える。
【００３２】
また２つの嵌合片１４a1，１４a2をある程度離して配置し、且つ２つの嵌合片１４b1，１４b2をある程度離して配置すると、溶融して２つの嵌合片１４a1，１４a2の間及び２つの嵌合片１４b1，１４b2の間に流れ出て硬化した半田の有無及びその量から、半田付け状態を視覚により簡単に確認できるので、半田付けの検査が容易になる。
【００３３】
カバー部材１０を半田付けする場合に、熱は半田付け電極１３ａ，１３ｂからアースパターン２へと伝達される。この伝達される熱の量が多くなればなるほど、半田付け不良が発生する可能性が高くなる。そこで一対の半田付け電極１３ａ，１３ｂとアースパターン２を電気的に接続する接続部１２ａ，１２ｂの幅寸法を１ｍｍ以下にするのが好ましい。このようにすると半田付け電極１３ａ，１３ｂからアースパターン２に逃げる熱の量を大幅に制限することができて、短い時間で半田付け作業を終了することができて、半田付け不良が発生するのを防止できる。なお、複数の端子電極３ａ〜３ｄのうちのアース電極３ｄもアースパターン２と接続部１２ｄにて電気的に接続されるため、ユニットの各端子電極３ａ〜３ｄを半田付けにより表面実装する際の半田付け不良の発生を防止するために、アース電極３ｄとアースパターン２とを接続する接続部１２ｄの幅寸法も１ｍｍ以下にするのが好ましい。
【００３４】
上記例では、本発明を温度補償型水晶発振器からなる電子部品ユニットに適用した場合について説明したが、本発明はこれに限定されるものではなく、例えば電圧制御形発振器等からなる電子部品ユニットにも同様に適用することができる。
【００３５】
また、上記例では嵌合部１４ａ，１４ｂを、回路基板の側面に沿って間隔をあけて形成したそれぞれ２つの嵌合片１４a1，１４a2、１４b1，１４b2により構成したが、本発明はこれに限定されるものではなく、各嵌合部は回路基板の側面に沿って形成した１以上の嵌合片により構成することができる。
【００３６】
【発明の効果】
本発明においては、カバー部材の一対の嵌合部を、回路基板の側面に沿って形成した１以上の嵌合片により構成し、これら嵌合片には半田付け電極側に向かって突出する突出部をそれぞれ形成したので、嵌合片と半田付け電極との上に塗布されて光ビームにより溶融した半田が突出部の周囲に回り込み、突出部の周囲に良好な半田フィレットを形成することができ、嵌合片と半田付け電極とを結合するに必要十分な量の半田を止どめることが可能になる。その結果、従来よりも半田付け強度が増大する。
【図面の簡単な説明】
【図１】（Ａ）は本発明に係る電子部品ユニットの実施の形態の一例で用いている回路基板の平面図、（Ｂ）はこの回路基板の裏面図である。
【図２】本例の電子部品ユニットで用いているカバー部材の平面図である。
【図３】（Ａ）（Ｂ）は図２に示すカバー部材の左側面図及び右側面図である。
【図４】（Ａ）（Ｂ）は図２に示すカバー部材の正面図及び背面図である。
【図５】本例で用いている嵌合片の構造を示す側面図である。
【図６】本例の電子部品ユニットにおける回路基板とカバー部材の電気的，機械的接続部分の縦断面図である。
【符号の説明】
１表面側回路パターン
２アースパターン
３ａ〜３ｄ端子電極
３ad〜３dd 凹部
４裏面側回路パターン
５回路基板
６，７ａ，７ｂ，…，８表面実装電子部品
９表面実装電子部品（トリマブルチップ抵抗器）
１０カバー部材
１０ｕ上板部
１０ａ〜１０ｄ側壁部
１０a1，１０b1，１０c1，１０d1 嵌合接触片
１０as，１０bs，１０cs，１０ds 接触部
１１ａ〜１１ｄ嵌合用凹部
１２ａ，１２ｂ，１２ｄ接続部
１３ａ，１３ｂ半田付け電極
１４ａ，１４ｂ嵌合部
１４a1，１４a2，１４b1，１４b2 嵌合片
１５突出部
１６ｃ，１６ｄ嵌合部
１７窓部
１８半田[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic component unit such as a temperature compensated crystal oscillator, and more specifically to a temperature compensated crystal oscillator.
[0002]
[Prior art]
Some conventional electronic component units such as temperature compensated crystal oscillators have a structure in which a metal cover member is attached to a circuit board. A surface-side circuit pattern on which a plurality of surface-mounted electronic components are surface-mounted is formed on the surface of a circuit board used in such an electronic component unit, and a ground that is electrically connected to the surface-side circuit pattern is formed on the back surface. A back side circuit pattern including a pattern and a plurality of terminal electrodes is formed. The cover member is formed so as to cover the plurality of surface mount electronic components. In order to attach the cover member to the circuit board, a pair of fitting recesses are formed on a pair of opposing side surfaces of the circuit board, and an inner surface of the pair of fitting recesses is electrically connected to the ground pattern. Each soldering electrode is formed. The cover member is integrally provided with a pair of fitting portions that are fitted into the pair of fitting recesses and soldered to the pair of soldering electrodes. Then, with the pair of fitting parts of the cover member fitted into the pair of fitting recesses of the circuit board, the pair of fitting parts are soldered to the pair of soldering electrodes, and the cover member is machined to the circuit board. And electrically connected. The soldering connection of the pair of fitting portions to the pair of soldering electrodes is performed by previously applying so-called cream solder on the joint portion between the pair of fitting portions and the pair of soldering electrodes. Is fitted into a pair of fitting recesses on the circuit board, and then the cream solder is irradiated with a light beam to melt the cream solder.
[0003]
[Problems to be solved by the invention]
The pair of fitting portions provided on the conventional cover member has one fitting piece that is fitted into the fitting recess and soldered to the soldering electrode. However, in a conventional electronic component unit, a sufficient amount of molten solder may not be retained between the fitting piece and the soldering electrode, and sufficient soldering strength may not be obtained. It was.
[0004]
An object of the present invention is to provide an electronic component unit and a temperature-compensated crystal oscillator in which a cover member can be easily soldered.
[0005]
Another object of the present invention is to provide an electronic component unit that allows easy confirmation of the soldered state of the cover member.
[0006]
Another object of the present invention is to provide an electronic component unit in which positioning of a cover member is easy.
[0007]
Still another object of the present invention is to provide an electronic component unit that requires less time for soldering the cover member.
[0008]
Another object of the present invention is to provide a temperature-compensated crystal oscillator that can prevent displacement and deformation of a cover member and can reliably perform laser trimming work of a triggerable chip resistor.
[0009]
[Means for Solving the Problems]
An electronic component unit such as a temperature-compensated crystal oscillator to be improved by the present invention includes a ground pattern and a plurality of terminal electrodes, each having a front side circuit pattern formed on the front side and electrically connected to the front side circuit pattern on the back side. A circuit board formed with a back side circuit pattern including a plurality of surface-mounted electronic components mounted on the front-side circuit pattern of the circuit board, and a plurality of surface-mounted electronic components on the surface of the circuit board And a metal cover member attached to the circuit board. A pair of fitting recesses are formed on a pair of opposing side surfaces of the circuit board. Solder electrodes electrically connected to the ground pattern are formed on the inner surfaces of the pair of fitting recesses. Further, the cover member is integrally provided with a pair of fitting portions that are fitted into the pair of fitting recesses and soldered to the pair of soldering electrodes. Then, with the pair of fitting portions of the cover member fitted in the pair of fitting concave portions of the circuit board, a pair of solder is disposed between the pair of fitting portions and the pair of soldering electrodes. The fitting portion is soldered and connected to the pair of soldering electrodes, and the cover member is mechanically and electrically connected to the circuit board. In the case of a temperature-compensated crystal oscillator, a plurality of surface-mount electronic components mounted on the surface-side circuit pattern of the circuit board constitute a temperature-compensated crystal oscillation circuit.
[0010]
In this invention, a pair of fitting part of a cover member is comprised by the 1 or more fitting piece formed along the side surface of a circuit board. The one or more fitting pieces are each formed with a protruding portion protruding toward the soldering electrode side. When such a structure is adopted, the solder applied on the fitting piece and the soldering electrode and melted by the light beam wraps around the protruding portion, and a good solder fillet can be formed around the protruding portion. This makes it possible to stop a sufficient amount of solder necessary to connect the fitting piece and the soldering electrode. As a result, the soldering strength is increased as compared with the conventional case.
[0011]
In particular, if one or more fitting pieces have a spring property that presses the protruding portion toward the soldering electrode, the cover member may be displaced from a predetermined position or lifted before starting the soldering operation. Can be prevented. Therefore, the soldering operation of the cover member is further facilitated. When the number of fitting pieces is 2 or more, the number of protrusions around which the molten solder wraps is also 2 or more, so that two or more good solder fillets can be formed, and the soldering strength can be further increased.
[0012]
Solder Fi LESSON bets shape formed wraps around the periphery of the protrusion according to the present invention, since the soldering state can be easily confirmed visually, thereby facilitating the inspection of soldering.
[0013]
Furthermore, a contact part which contacts the surface of a circuit board is provided in a pair of fitting part, and another pair of recessed part for fitting is formed in another pair of side surface different from a pair of side surface of a circuit board, and also a cover member The pair of side wall portions different from the pair of side wall portions provided with the pair of fitting portions are in contact with the surface of the circuit board and the fitting portion fitted into another pair of fitting recesses of the circuit board. When the pair of fitting contact pieces having the contact portions are integrally provided, the cover member can be accurately positioned with respect to the circuit board. In particular, when manufacturing a temperature compensated crystal oscillator in which a surface mount electronic component includes a trimmable chip resistor that is subjected to laser trimming for frequency adjustment, the trimmable chip resistor is exposed to the cover member. A window part will be formed. Laser trimming is performed through this window. In this case, if the mounting posture of the cover member is bad or the cover member is bent greatly, the position and shape of the window portion may be different from the design, which may hinder laser trimming. However, when the structure as described above is employed, the cover member can be accurately positioned with respect to the circuit board, and the cover member can be prevented from being greatly deformed, so that laser trimming of the trimmable chip resistor can be performed more reliably. .
[0014]
When the cover member is soldered, heat is transferred from the soldering electrode to the ground pattern. The greater the amount of heat transferred, the higher the likelihood of soldering failure. Therefore, it is preferable that the width dimension of the connection portion for electrically connecting the pair of soldering electrodes and the ground pattern is 1 mm or less. In this way, the amount of heat that escapes from the soldering electrode to the ground pattern can be greatly limited, the soldering operation can be completed in a short time, and the occurrence of poor soldering can be prevented. Since the earth electrode of the plurality of electrodes is also electrically connected to the earth pattern, the earth electrode and the earth pattern are used in order to prevent the occurrence of soldering defects when the electrodes of the unit are surface-mounted by soldering. It is preferable that the width dimension of the connecting portion connecting the two is also 1 mm or less.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
FIGS. 1A and 1B to FIG. 5 show an example of an embodiment in which the present invention is applied to an electronic component unit composed of a temperature compensated crystal oscillator. FIGS. 1A and 1B show this example. FIG. 2 is a plan view of a cover member used in this example, FIGS. 3A and 3B are a left side view and a right side view of FIG. (A) and (B) are a front view and a rear view of FIG. 2, FIG. 5 is a side view showing the structure of a fitting piece used in this example, and FIG. 6 is a circuit board and a cover member in the electronic component unit of this example. It is a longitudinal cross-sectional view of the electrical and mechanical connection part.
[0016]
As shown in FIGS. 1A and 1B, the electronic component unit has a ground pattern 2 formed on the front surface and a ground pattern 2 electrically connected to the front circuit pattern 1 on the back surface and a plurality of terminals. A rectangular circuit board 5 on which a back-side circuit pattern 4 including electrodes 3a to 3d is formed, and a plurality of circuits that are mounted on the front-side circuit pattern 1 of the circuit board 5 to constitute a temperature-compensated crystal oscillation circuit. The surface mount electronic components 6, 7 a, 7 b,..., 8, 9, etc. and the plurality of surface mount electronic components 6, 7 a, 7 b,. A metal cover member 10 as shown in FIGS. 2 to 5 attached to the circuit board 5 is provided.
[0017]
The terminal electrodes 3a to 3d are provided on the periphery of the circuit board 5, and the peripheral edges of the circuit board 5 at the locations of the terminal electrodes 3a to 3d are provided with recesses 3ad to 3dd that open to the side surfaces. The terminal electrodes 3a to 3d are also present on the inner surface of 3dd.
[0018]
Of the surface-mounted electronic components 6, 7a, 7b,..., 8, 9, etc., the surface-mounted electronic component 9 is composed of a trimmable chip resistor that is subjected to laser trimming for frequency adjustment.
[0019]
A pair of fitting recesses 11 a and 11 b are formed on a pair of opposing side surfaces of the circuit board 5. Soldering electrodes 13a and 13b that are electrically connected to the ground pattern 2 and the connecting portions 12a and 12b are formed on the inner surfaces of the pair of fitting recesses 11a and 11b, respectively. Each connection part 12a, 12b is formed in a width dimension of 1 mm or less.
[0020]
Are electrically connected at the ground electrode 3 c also earth pattern 2 and the connecting portion 12d of the plurality of terminal electrodes 3 a to 3 d. In this case, the width of the connecting portion 12d is also preferably 1 mm or less.
[0021]
A pair of fitting recesses 11c and 11d are formed in the center of the other pair of side surfaces of the circuit board 5 that face each other.
[0022]
The cover member 10 has a rectangular shape so that the upper plate portion 10u covers the surface of the circuit board 5, and four rectangular side wall portions 10a to 10a are formed on the peripheral edge portion of the rectangular upper plate portion 10u. 10d is continuously provided so as to form a rectangular tube shape downward. Each of the side wall portions 10 a to 10 d having a rectangular tube shape is supported by the upper plate portion 10 u in such a positional relationship as to be placed on the peripheral edge portion of the upper surface of the circuit board 5.
[0023]
Fitting contact pieces 10a1 and 10b1 having contact portions 10as and 10bs that are placed on and contact with the peripheral edge of the upper surface of the circuit board 5 are provided at the lower portion of the cover member 10 near the center of the pair of side wall portions 10a and 10b. It has been. At the lower ends of the fitting contact pieces 10a1 and 10b1, a pair of fitting portions 14a fitted into the pair of fitting recesses 11a and 11b of the circuit board 5 and soldered to the pair of soldering electrodes 13a and 13b. , 14b are integrally provided. The pair of fitting portions 14a and 14b are constituted by two fitting pieces 14a1 and 14a2 and two fitting pieces 14b1 and 14b2 formed at intervals along the side surface of the circuit board 5. The distance between the two fitting pieces 14a1 and 14a2 and the distance between the two fitting pieces 14b1 and 14b2 are set to dimensions that allow the soldered state to be confirmed visually. Projecting portions 15 projecting toward the corresponding soldering electrodes 13a, 13b are provided on the inward surfaces of the two fitting pieces 14a1, 14a2 and the two fitting pieces 14b1, 14b2, respectively. Each is formed by punching as shown in FIG. The two fitting pieces 14a1 and 14a2 and the two fitting pieces 14b1 and 14b2 have a spring property that presses the protrusions 15 toward the soldering electrodes 13a and 13b of the circuit board 5.
[0024]
Different from the pair of facing side wall portions 10a, 10b of the cover member 10, the lower portion of the other pair of facing side wall portions 10c, 10d is located on the lower peripheral portion of the circuit board 5 and contacts the lower portion. Fitting contact pieces 10c1 and 10d1 having 10cs and 10ds are provided. At the lower ends of these fitting contact pieces 10c1 and 10d1, a pair of opposing fitting recesses 11c provided on the other pair of side surfaces different from the fitting recesses 11a and 11b provided on the pair of side surfaces of the circuit board 5 are provided. , 11d, a pair of fitting portions 16c, 16d are integrally provided.
[0025]
On the upper plate portion 10u of the cover member 10, a window portion 17 for exposing the surface mount electronic component 9 to a position corresponding to the surface mount electronic component 9 made of a trimmable chip resistor subjected to laser trimming for frequency adjustment. Is formed. The window portion 17 is formed close to one fitting portion 14 a of the cover member 10.
[0026]
In such an electronic component unit, the cover member 10 is placed on the surface-side circuit pattern 1 side of the circuit board 5 as shown by broken lines in FIGS. 3 (A), 3 (B) and 4 (A), 4 (B). . At this time, the fitting contact pieces 10 a 1, 10 b 1, 10 c 1, 10 d 1 of the cover member 10 are placed in contact with the lower edge contact portions 10 as, 10 bs, 10 cs, 10 ds on the peripheral edge of the upper surface of the circuit board 5. At this time, the pair of fitting pieces 14a1 and 14a2 projecting from the tips of the fitting contact pieces 10a1 are fitted into the fitting recesses 11a of the circuit board 5, and the tip sides of the fitting pieces 14a1 and 14a2 are fitted. Each projecting portion 15 on each inward surface of the circuit board 5 is in contact with the soldering electrode 13 a in the fitting recess 11 a of the circuit board 5. Similarly, a pair of fitting pieces 14b1 and 14b2 projecting from the tips of the fitting contact pieces 10b1 are fitted into the fitting recesses 11b of the circuit board 5, and on the tip side of the fitting pieces 14b1 and 14b2. Each protrusion 15 on each inward surface is in contact with the soldering electrode 13b in the fitting recess 11b of the circuit board 5, respectively. Further, the fitting portions 16 c and 16 d protruding from the tips of the fitting contact pieces 10 c 1 and 10 d 1 are fitted into the fitting recesses 11 c and 11 d of the circuit board 5.
[0027]
In this state, the circuit board 5 is turned upside down so that the rear surface side of the circuit board 5 faces upward, and the protrusions 15 on the front end side of the fitting pieces 14a1 and 14a2 of the cover member 10 are in contact with the soldering electrodes 13a of the circuit board 5, respectively. The required amount of cream solder is placed on the upper surface of the cover member 10 and the upper surface of the portion where the protrusions 15 on the tip side of the fitting pieces 14b1 and 14b2 of the cover member 10 are in contact with the soldering electrodes 13b of the circuit board 5, respectively. Then, the cream solder is irradiated with a light beam such as a laser to completely melt the cream solder, and the protrusions 15 of the fitting pieces 14a1 and 14a2 of the cover member 10 are connected to the circuit board as shown in FIG. 5 are connected to the soldering electrodes 13 a by the solder 18, and the protrusions 15 of the fitting pieces 14 b 1 and 14 b 2 of the cover member 10 are connected to the soldering electrodes 13 b of the circuit board 5 by the solder 18.
[0028]
When such an electronic component unit is used, laser trimming is performed on the surface-mounted electronic component 9 made of a trimmable chip resistor by using the window portion 17 of the cover member 10, and the electronic component made of a temperature-compensated crystal oscillator. Adjust the frequency of the unit.
[0029]
In the present invention, the pair of fitting portions 14a, 14b of the cover member 10 is constituted by a pair of fitting pieces 14a1, 14a2, 14b1, 14b2 formed at intervals along the side surface of the circuit board 5, and these Since the fitting pieces 14a1, 14a2, 14b1, 14b2 are formed with protruding portions 15 projecting toward the corresponding soldering electrodes 13a, 13b, respectively, a pair of fitting portions 14a, 14b of the cover member 10 and a circuit are formed. The contact area between the soldering electrodes 13a and 13b provided in the fitting recesses 11a and 11b of the substrate 10 is increased, the thermal conductivity is increased, and the contact points are dispersed. Therefore, the solder 18 coated on the fitting pieces 14a1, 14a2, 14b1, 14b2 and the soldering electrodes 13a, 13b and melted by the light beam surely wraps around the pair of fitting portions 11a, 11b, and covers the cover. The soldering work of the member 10 becomes easy. In this case, if each pair of fitting pieces 14a1, 14a2, 14b1, 14b2 has a spring property that presses the protruding portion 15 toward the soldering electrodes 13a, 13b, before starting the soldering operation. Further, it is possible to prevent the cover member 10 from being shifted from a predetermined position or lifted. Therefore, the soldering operation of the cover member 10 is further facilitated.
[0030]
Further, in this cover member 10, contact portions 14 as and 14 bs that contact the surface of the circuit board 5 are provided at the tips of the pair of fitting portions 14 a and 14 b, and another pair of side surfaces different from the pair of side surfaces of the circuit board 5. A pair of other side wall portions 10c different from the pair of side wall portions 10a, 10b provided with the pair of fitting portions 14a, 14b of the cover member 10 is formed. , 10d, a pair of mating contacts having mating portions 16c, 16d fitted in another pair of mating recesses 11c, 11d of the circuit board 5 and contact portions 14cs, 14ds contacting the surface of the circuit board 5 If the pieces 10c1 and 10d1 are provided integrally, the cover member 10 can be accurately positioned with respect to the circuit board 5.
[0031]
In particular, when manufacturing a temperature compensated crystal oscillator in which a surface mount electronic component includes a trimmable chip resistor that is subjected to laser trimming for frequency adjustment, the trimmable chip resistor is exposed on the cover member 10. The window part 9 to be made is formed. Laser trimming is performed through the window 9. In this case, if the mounting posture of the cover member 10 is bad or the cover member 10 is bent greatly, the position and shape of the window portion 9 are different from the design, which may hinder laser trimming. However, if the structure as described above is adopted, the cover member 10 can be accurately positioned with respect to the circuit board 5 and a large deformation of the cover member 10 can be prevented, so that laser trimming of the trimmable chip resistor can be further performed. It can be done reliably.
[0032]
Further, when the two fitting pieces 14a1 and 14a2 are arranged apart from each other and the two fitting pieces 14b1 and 14b2 are arranged apart from each other to some extent, the two fitting pieces 14a1 and 14a2 melt and melt between the two fitting pieces 14a1 and 14a2. Since the soldering state can be easily visually confirmed from the presence and amount of the solder that has flowed out and hardened between the pieces 14b1 and 14b2, the soldering inspection is facilitated.
[0033]
When the cover member 10 is soldered, heat is transmitted from the soldering electrodes 13a and 13b to the ground pattern 2. The greater the amount of heat transferred, the higher the likelihood of soldering failure. Therefore, it is preferable that the width dimension of the connecting portions 12a and 12b for electrically connecting the pair of soldering electrodes 13a and 13b and the ground pattern 2 is 1 mm or less. In this way, the amount of heat that escapes from the soldering electrodes 13a and 13b to the ground pattern 2 can be greatly limited, and the soldering operation can be completed in a short time, resulting in poor soldering. Can be prevented. In addition, since the earth electrode 3d of the plurality of terminal electrodes 3a to 3d is also electrically connected to the earth pattern 2 through the connection portion 12d, the terminal electrodes 3a to 3d of the unit are mounted on the surface by soldering. In order to prevent the occurrence of soldering defects, it is preferable that the width dimension of the connecting portion 12d for connecting the ground electrode 3d and the ground pattern 2 is also 1 mm or less.
[0034]
In the above example, the case where the present invention is applied to an electronic component unit composed of a temperature-compensated crystal oscillator has been described. However, the present invention is not limited to this, for example, an electronic component unit composed of a voltage-controlled oscillator or the like. Can be applied similarly.
[0035]
In the above example, the fitting portions 14a and 14b are configured by two fitting pieces 14a1, 14a2, 14b1, and 14b2 formed at intervals along the side surface of the circuit board. However, the present invention is not limited to this. Instead, each fitting portion can be composed of one or more fitting pieces formed along the side surface of the circuit board.
[0036]
【The invention's effect】
In the present invention, the pair of fitting portions of the cover member is constituted by one or more fitting pieces formed along the side surface of the circuit board, and these fitting pieces protrude from the soldering electrode side. Since each part is formed, the solder applied on the fitting piece and the soldering electrode and melted by the light beam wraps around the protruding part, and a good solder fillet can be formed around the protruding part. Thus, it becomes possible to stop a sufficient amount of solder necessary for coupling the fitting piece and the soldering electrode. As a result, the soldering strength is increased as compared with the conventional case.
[Brief description of the drawings]
FIG. 1A is a plan view of a circuit board used in an example of an embodiment of an electronic component unit according to the present invention, and FIG. 1B is a back view of the circuit board.
FIG. 2 is a plan view of a cover member used in the electronic component unit of this example.
3A and 3B are a left side view and a right side view of the cover member shown in FIG.
4A and 4B are a front view and a rear view of the cover member shown in FIG.
FIG. 5 is a side view showing a structure of a fitting piece used in this example.
FIG. 6 is a longitudinal sectional view of an electrical and mechanical connection portion between a circuit board and a cover member in the electronic component unit of this example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Surface side circuit pattern 2 Ground pattern 3a-3d Terminal electrode 3ad-3dd Recessed part 4 Back surface side circuit pattern 5 Circuit board 6, 7a, 7b, ..., 8 Surface mount electronic component 9 Surface mount electronic component (trimmable chip resistor)
DESCRIPTION OF SYMBOLS 10 Cover member 10u Upper board part 10a-10d Side wall part 10a1, 10b1, 10c1, 10d1 Fitting contact piece 10as, 10bs, 10cs, 10ds Contact part 11a-11d Fitting recessed part 12a, 12b, 12d Connection part 13a, 13b Soldering Electrodes 14a, 14b Fitting portions 14a1, 14a2, 14b1, 14b2 Fitting pieces 15 Protruding portions 16c, 16d Fitting portions 17 Window portions 18 Solder

Claims

A circuit board on which a front surface side circuit pattern is formed and a back surface side circuit pattern including a ground pattern electrically connected to the front surface side circuit pattern and a plurality of terminal electrodes is formed on the back surface;
A plurality of surface-mounted electronic components mounted on the surface-side circuit pattern of the circuit board;
A metal cover member formed to cover the plurality of surface-mounted electronic components on the surface of the circuit board and attached to the circuit board;
A pair of fitting recesses are formed on the pair of opposing side surfaces of the circuit board,
Soldering electrodes electrically connected to the ground pattern are formed on the inner surfaces of the pair of fitting recesses,
The cover member is integrally provided with a pair of fitting portions that are fitted into the pair of fitting recesses and soldered to the pair of soldering electrodes,
Solder disposed between the pair of fitting portions and the pair of soldering electrodes in a state where the pair of fitting portions of the cover member are fitted in the pair of fitting concave portions of the circuit board. An electronic component unit in which the pair of fitting portions are soldered to the pair of soldering electrodes via the cover member and the cover member is mechanically and electrically connected to the circuit board,
The pair of the fitting portion of the cover member is constituted by the two or more mating pieces formed along the sides of the circuit board, wherein the two or more mating pieces toward the soldering electrode side An electronic component unit, wherein one protruding portion that protrudes is formed.

The electronic component unit according to claim 1, wherein the two or more fitting pieces have a spring property that presses the protruding portion toward the soldering electrode.

2. The electronic component unit according to claim 1, wherein a connecting portion that electrically connects the pair of soldering electrodes and the ground pattern has a width dimension of 1 mm or less.

The pair of fitting portions are provided with contact portions that come into contact with the surface of the circuit board,
Another pair of fitting recesses are formed on another pair of side surfaces different from the pair of side surfaces of the circuit board,
The other pair of side wall portions different from the pair of side wall portions provided with the pair of fitting portions of the cover member are fitted into the other pair of fitting recesses of the circuit board. 2. The electronic component unit according to claim 1, wherein a pair of fitting contact pieces having a contact portion that contacts with the surface of the circuit board are integrally provided.

A circuit board on which a front surface side circuit pattern is formed and a back surface side circuit pattern including a ground pattern electrically connected to the front surface side circuit pattern and a plurality of terminal electrodes is formed on the back surface;
A plurality of surface-mount electronic components mounted on the surface-side circuit pattern of the circuit board and constituting a temperature-compensated crystal oscillation circuit;
A metal cover member formed to cover the plurality of surface-mounted electronic components on the surface of the circuit board and attached to the circuit board;
A pair of fitting recesses are formed on the pair of opposing side surfaces of the circuit board,
Soldering electrodes electrically connected to the ground pattern are formed on the inner surfaces of the pair of fitting recesses,
The cover member is integrally provided with a pair of fitting portions that are fitted into the pair of fitting recesses and soldered to the pair of soldering electrodes,
Solder disposed between the pair of fitting portions and the pair of soldering electrodes in a state where the pair of fitting portions of the cover member are fitted in the pair of fitting concave portions of the circuit board. A temperature-compensated crystal oscillator in which the pair of fitting parts are soldered to the pair of soldering electrodes via the cover member and the cover member is mechanically and electrically connected to the circuit board,
The pair of the fitting portion of the cover member is constituted by the two or more mating pieces formed along the sides of the circuit board, wherein the two or more mating pieces toward the soldering electrode side A temperature-compensated crystal oscillator characterized in that one projecting portion projecting is formed.

The surface mount electronic component includes a trimmable chip resistor that is laser trimmed for frequency adjustment,
The cover member is formed with a window portion exposing the trimmable chip resistor,
6. The temperature compensated crystal oscillator according to claim 5 , wherein the window portion is formed close to one of the fitting portions.

The surface mount electronic component includes a trimmable chip resistor that is laser trimmed for frequency adjustment,
The cover member is formed with a window portion exposing the trimmable chip resistor,
The pair of fitting portions have contact portions that come into contact with the surface of the circuit board,
Another pair of fitting recesses are formed on another pair of side surfaces different from the pair of side surfaces of the circuit board,
The other pair of side wall portions different from the pair of side wall portions provided with the pair of fitting portions of the cover member are fitted into the other pair of fitting recesses of the circuit board. The temperature-compensated crystal oscillator according to claim 5 , wherein a pair of fitting contact pieces having a contact portion that contacts with the surface of the circuit board are integrally provided.