JP4376527B2

JP4376527B2 - Optical scanning device

Info

Publication number: JP4376527B2
Application number: JP2003055992A
Authority: JP
Inventors: 譲上田; 孝通柳沢
Original assignee: Nippon Signal Co Ltd; Citizen Finetech Miyota Co Ltd
Current assignee: Nippon Signal Co Ltd; Citizen Finetech Miyota Co Ltd
Priority date: 2003-03-03
Filing date: 2003-03-03
Publication date: 2009-12-02
Anticipated expiration: 2023-03-03
Also published as: JP2004264684A

Description

【０００１】
【発明の属する技術分野】
本発明は、半導体基板により一体的に形成するプレーナ型の光走査装置に関し、特に、可動板に発生する応力を表裏面でバランスさせて可動板の反り変形を抑制すると共に、駆動力の向上を可能にする光走査装置に関する。
【０００２】
【従来の技術】
従来の光走査装置には、半導体基板の固定部にトーションバーで揺動可能に軸支され中央部に反射ミラーを形成した可動板と、該可動板の周縁部に沿って敷設した薄膜コイルと、トーションバーの軸方向に平行な上記可動板の対辺近傍部の上記薄膜コイル部分に静磁界を作用して薄膜コイルを流れる電流と上記静磁界との相互作用により駆動力を発生して可動板を揺動させる静磁界発生手段とを備えて構成したものや、上記可動板に薄膜磁石を形成し、上記トーションバーの軸方向に平行な可動板の対辺側方の上記固定部の部位に駆動コイルを形成し、該駆動コイルの電磁界と上記薄膜磁石の静磁界の相互作用により駆動力を発生し可動板を揺動させるように構成したもの（例えば、特許文献１参照）がある。
【０００３】
【特許文献１】
特許第２７２２３１４号公報
【０００４】
【発明が解決しようとする課題】
しかし、このような従来の光走査装置において、例えば前者の場合は、可動板に成膜形成された薄膜コイル及び反射ミラー並びに薄膜コイルの保護及び絶縁を目的として形成するポリイミド等の保護膜の残留圧縮応力により、また後者の場合は、可動板に成膜形成された薄膜磁石及び反射ミラーの残留圧縮応力によって可動板に反りが発生する虞がある。
【０００５】
また、可動板に薄膜コイルを設けたものの場合は、通電により薄膜コイルに熱が発生する。したがって、この熱により薄膜コイル及び反射ミラー材料と可動板の基板材料との熱膨張率の違いに起因するバイメタル作用により可動板に反りが生じる虞がある。
【０００６】
そこで、本発明は上記問題点に着目してなされたもので、可動板に発生する応力を表裏面でバランスさせて可動板の反り変形を抑制すると共に、駆動力の向上を可能にする光走査装置を提供することを目的とする。
【０００７】
【課題を解決するための手段】
このために、請求項１の第１の発明は、半導体基板からなる固定部に、平板状の可動板と該可動板を固定部に対して揺動可能に軸支するトーションバーとを一体的に形成し、前記可動板の周縁部に沿って通電により磁界を発生する薄膜コイルを敷設し、前記可動板に反射ミラーを設ける一方、前記トーションバーの軸方向に平行な可動板の対辺部の薄膜コイル部分に対して静磁界を作用させる静磁界発生手段を備えて構成する光走査装置であって、前記可動板の表裏面に前記薄膜コイル及び前記反射ミラーをそれぞれ一対設けると共に、前記各薄膜コイル及び反射ミラーの膜厚または材質若しくは形状を異ならせて前記可動板の表裏面における応力をバランスさせた。
【０００８】
このような構成により、半導体基板からなる平板状の可動板の表裏面に薄膜コイル及び反射ミラーをそれぞれ一対設けると共に、各薄膜コイル及び反射ミラーの膜厚または材質若しくは形状を異ならせて可動板の表裏面における応力をバランスさせ、可動板の反りを抑制する。これにより、光走査精度を向上する。また、一対の薄膜コイルを可動板駆動用として用いることで駆動力の増大を可能とする。
【０００９】
この場合、請求項２のように前記一対の薄膜コイルを可動板周縁部に敷設し、前記一対の反射ミラーを前記薄膜コイルの内側に形成するとよい。または、請求項３のように前記一対の薄膜コイルを可動板上に敷設し、前記一対の反射ミラーを前記薄膜コイルの上面に絶縁層を介して積層してもよい。
【００１０】
また、請求項４の構成の場合においては、前記可動板が、固定部に外側トーションバーで揺動可能に軸支された枠状の外側可動板と、該外側可動板に前記外側トーションバーの軸線と直交する内側トーションバーで揺動可能に軸支された内側可動板とからなり、前記外側可動板の表裏面に外側薄膜コイルを一対敷設し、前記内側可動板の表裏面の周縁部に沿って内側薄膜コイルを一対敷設すると共に、前記内側可動板の表裏面に反射ミラーを一対設ける構成とした。
【００１１】
この場合、請求項５のように前記一対の内側薄膜コイルを内側可動板周縁部に敷設し、前記一対の反射ミラーを前記内側薄膜コイルの内側に形成するとよい。または、請求項６のように前記一対の内側薄膜コイルを内側可動板上に敷設し、前記一対の反射ミラーを前記内側薄膜コイルの上面に絶縁層を介して積層してもよく、請求項７のように前記一対の外側薄膜コイルの上面に絶縁層を介して反射ミラーを一対積層してもよい。
【００１２】
また、請求項８のように前記可動板の表裏面に敷設した一対の薄膜コイルを直列接続するとよく、または請求項９のように前記可動板の表裏面に敷設した一対の薄膜コイルを並列接続してもよい。
【００１３】
また、請求項１０の第２の発明は、半導体基板からなる固定部に、平板状の可動板と該可動板を固定部に対して揺動可能に軸支するトーションバーとを一体的に形成し、前記可動板に静磁界を発生する薄膜磁石と反射ミラーとを設ける一方、前記トーションバーの軸方向に平行な前記可動板の対辺部の薄膜磁石部分に対して通電により発生する磁界を作用させる駆動コイルを備えて構成する光走査装置であって、前記可動板の表裏面に前記薄膜磁石及び前記反射ミラーをそれぞれ一対設けると共に、前記各薄膜磁石及び反射ミラーの膜厚または材質若しくは形状を異ならせて前記可動板の表裏面における応力をバランスさせた。
【００１４】
このような構成により、半導体基板からなる平板状の可動板の表裏面に薄膜磁石及び反射ミラーをそれぞれ一対設けると共に、各薄膜磁石及び反射ミラーの膜厚または材質若しくは形状を異ならせて可動板の表裏面における応力をバランスさせ、可動板の反りを抑制する。これにより、光走査精度を向上する。また、一対の薄膜磁石を可動板駆動用に用いることで駆動力の増大を可能とする。
【００１５】
この場合、請求項１１のように、前記一対の薄膜磁石を可動板周縁部に形成し、前記一対の反射ミラーを前記薄膜磁石の内側に形成するとよい。または、請求項１２のように前記一対の薄膜磁石を可動板上に形成し、前記一対の反射ミラーを前記薄膜磁石の上面に積層してもよい。
【００１６】
また、請求項１３の構成の場合においては、前記可動板が、固定部に外側トーションバーで揺動可能に軸支された枠状の外側可動板と、該外側可動板に前記外側トーションバーの軸線と直交する内側トーションバーで揺動可能に軸支された内側可動板とからなり、少なくとも前記内側可動板の表裏面に静磁界を発生する薄膜磁石と反射ミラーとをそれぞれ一対設ける構成とした。
【００１７】
この場合、請求項１４のように前記一対の薄膜磁石を内側可動板周縁部に形成し、前記一対の反射ミラーを前記内側薄膜磁石の内側に形成するとよい。または、請求項１５のように前記一対の薄膜磁石を内側可動板上に形成し、前記一対の反射ミラーを前記内側薄膜磁石の上面に積層してもよく、請求項１６のように前記外側可動板の表裏面に一対の薄膜磁石を形成してもよい。さらに、請求項１７のように前記外側可動板の表裏面に形成した前記一対の薄膜磁石の上面に一対の反射ミラーを形成してもよい。
【００１８】
また、請求項１８のように前記可動板の中央部と該可動板端部との間に、可動板端部から前記可動板中央部に伝達する可動板中央部の変形要因を抑制する境界部を設けてもよい。または、請求項１９のように前記内側可動板の中央部と該内側可動板端部との間に、内側可動板端部から前記内側可動板中央部に伝達する内側可動板中央部の変形要因を抑制する境界部を設けてもよい。
【００１９】
さらに、請求項２０のように前記各薄膜コイル及び反射ミラー並びに境界部、または前記各薄膜磁石及び反射ミラー並びに境界部を前記各可動板の表裏面の同一位置に形成するとよい。
【００２１】
【発明の実施の形態】
以下、本発明の実施の形態を添付図面に基づいて詳細に説明する。
図１に、本発明に係る光走査装置の第１実施形態の概略構成を分解斜視図で示す。
図１において、本第１実施形態の光走査装置は、半導体基板により一体的に形成した一次元の光走査装置であり、可動板１と、薄膜コイル２Ａ，２Ｂと、反射ミラー３Ａ，３Ｂと、静磁界発生手段４Ａ，４Ｂと、を備えて構成する。
【００２２】
上記可動板１は、枠状の固定部５にトーションバー６で揺動可能に軸支されたものであり、半導体基板をその厚み方向に異方性エッチングして固定部５及びトーションバー６と一体的に形成される。また、可動板１の表裏面には、後述の反射ミラー３Ａ，３Ｂを一対設けており、可動板１の揺動に伴って上記反射ミラー３Ａ（または３Ｂ）で光ビームを反射して一次元走査するようにしている。なお、半導体基板は、半導体微細加工技術を応用して加工するものであれば如何なるものであってもよく、例えばシリコン基板やプラスチック基板などである。
【００２３】
上記可動板１の表裏面には、該可動板１の周縁部に沿ってそれぞれ薄膜コイル２Ａ，２Ｂを敷設している。該薄膜コイル２Ａ，２Ｂは、トーションバー６の軸方向に平行な上記可動板１の対辺近傍部の薄膜コイル２Ａ，２Ｂを流れる電流に、後述する静磁界発生手段４Ａ，４Ｂから発生する静磁界を作用させて可動板１の上記対辺部に駆動力を発生させ可動板１を揺動させるものであり、半導体製造プロセスにより、例えばアルミニウム等の導電性薄膜をエッチングして形成される。そして、薄膜コイル２Ａ，２Ｂの両端部は、それぞれトーションバー６を介して固定部５に形成した電極端子部７Ａ，７Ｂに接続し、図示省略の制御回路から駆動電流が供給できるようになっている。なお、図１においては、薄膜コイル２Ａ，２Ｂを並列接続した構成で示しているが、例えば図１中右側の電極端子部７Ａと同図中左側の電極端子部７Ｂとを接続して薄膜コイル２Ａ，２Ｂを直列接続してもよい。
【００２４】
上記可動板１の表裏面で、図２（ａ）に示すように薄膜コイル２Ａ，２Ｂの内側には、それぞれ反射ミラー３Ａ，３Ｂを設ける。該反射ミラー３Ａ（または３Ｂ）は、入射する光ビームを反射するものであり、例えばアルミニウム等から成る反射膜を真空蒸着またはスパッタリング等により成膜して形成する。または、図２（ｂ）に示すように薄膜コイル２Ａ，２Ｂ上に設けたポリイミド等の絶縁層８を介して可動板１の全面を覆って反射ミラー３Ａ，３Ｂを形成してもよい。そして、上記薄膜コイル２Ａ，２Ｂ及び反射ミラー３Ａ，３Ｂは、可動板１の表裏面で同一位置に形成される。
【００２５】
そして、上記トーションバー６の軸方向に平行な可動板１の対辺側方で、例えば固定部５の上面部位には、上記可動板１を間にして一対の静磁界発生手段４Ａ，４Ｂを互いに反対磁極を対向させて備える。該静磁界発生手段４Ａ，４Ｂは、可動板１の上記対辺近傍部の薄膜コイル２Ａ，２Ｂに対して可動板１に平行で薄膜コイル２Ａ，２Ｂに直交する成分を作用させ、該薄膜コイル２Ａ，２Ｂを流れる電流との相互作用によりローレンツ力を発生させるものであり、例えば永久磁石である。なお、静磁界発生手段４Ａ，４Ｂは、固定部５の上面部位ではなく、その外側に配置してもよい。
【００２６】
次に本発明の第１実施形態の動作を説明する。
先ず、図１に示す並列接続された薄膜コイル２Ａ，２Ｂに、図示省略の制御回路から電極端子部７Ａ，７Ｂを介して駆動電流がそれぞれ供給される。この場合、トーションバー６の軸方向に平行な可動板１の対辺近傍部の上記薄膜コイル２Ａ，２Ｂの部分には、該部分に対向して配置された静磁界発生手段４Ａ，４Ｂにより静磁界が作用している。したがって、該静磁界のうち可動板１に平行で薄膜コイル２Ａ，２Ｂの上記部分に直交する静磁界成分が、薄膜コイル２Ａ，２Ｂの該部分を流れる電流と相互に作用して薄膜コイル２Ａ，２Ｂの当該部分にローレンツ力を発生させ可動板１を揺動させる。そして、可動板１の揺動に伴って、可動板１に形成した反射ミラー３Ａ（または３Ｂ）で光ビームを一次元走査する。
【００２７】
可動板１の駆動時には、可動板１の表裏面に設けた薄膜コイル２Ａ，２Ｂに同じ大きさの駆動電流が流れる。したがって、薄膜コイル２Ａ，２Ｂにおいて発生する発熱量は等しい。しかも、薄膜コイル２Ａ，２Ｂは、可動板１の表裏面で同一位置に形成されているため可動板１の表裏面に発生する熱応力がバランスして可動板１の反りが抑制される。
【００２８】
また、可動板１の表裏面には、薄膜コイル２Ａ，２Ｂ及び反射ミラー３Ａ，３Ｂが可動板１表裏面で同一位置に形成されているため上記薄膜コイル２Ａ，２Ｂ及び反射ミラー３Ａ，３Ｂの薄膜の残留圧縮応力による反り力が可動板１の表裏面の各部でバランスし、可動板１の反りを抑制する。なお、薄膜の残留圧縮応力が、薄膜の形成条件により異なる場合があるため、本第１実施形態においては、上記薄膜コイル２Ａ，２Ｂ及び反射ミラー３Ａ，３Ｂ並びに絶縁層８の膜厚または材質若しくは形状を異ならせる等調整して可動板１の表裏面における応力をバランスさせている。
【００２９】
このように、上記第１実施形態によれば、可動板１の表裏面に薄膜コイル２Ａ，２Ｂ及び反射ミラー３Ａ，３Ｂをそれぞれ形成すると共に、各薄膜コイル２Ａ，２Ｂ及び反射ミラー３Ａ，３Ｂの膜厚または材質若しくは形状を異ならせて可動板１の表裏面における薄膜の残留圧縮応力をバランスさせたことにより、薄膜の残留圧縮応力による反り力が可動板１の表裏面でバランスし、可動板１の反りの発生を抑制することができる。また、薄膜コイル２Ａ，２Ｂ及び反射ミラー３Ａ，３Ｂを可動板１の表裏面の同一位置に形成したことにより、薄膜の残留圧縮応力の発生部位が可動板１の表裏面で略一致し、該応力を相殺して可動板１の反りをより効果的に抑制することができる。
【００３０】
また、該薄膜コイル２Ａ，２Ｂの両者に通電して可動板１を揺動させる構成としたことにより、薄膜コイル２Ａ，２Ｂに発生する熱が可動板１の表裏面で略等しくなり、この発熱による熱応力が可動板１の表裏面でバランスして反りの発生を抑制することができる。これにより、光走査精度を向上することができる。
【００３１】
さらに、可動板１の表裏面に形成した薄膜コイル２Ａ，２Ｂを並列接続する構成としたことにより、可動板１の一方の側だけに薄膜コイルを設けた従来の光走査装置に比べ駆動力を同一とした場合、各薄膜コイル２Ａ，２Ｂに流れる電流値が半分になり、薄膜コイル２Ａ，２Ｂにおける発熱を低減することができる。言うまでもないが、可動板１の表裏面の各薄膜コイル２Ａ，２Ｂに従来と同じ電流値を供給すれば２倍の駆動力を得られる。また、薄膜コイル２Ａ，２Ｂを直列接続した場合には、従来の光走査装置に比べて同じ電流値で約２倍の駆動力を得ることができる。
【００３２】
次に、本発明に係る光走査装置の第２実施形態を図３及び図４を参照して説明する。なお、第１実施形態と同一の要素については同一符号を用いて示し、ここでは、第１実施形態と異なる部分についてのみ説明する。
図３は、第２実施形態の光走査装置の概略構成を示す分解斜視図である。この光走査装置は、光ビームを二次元走査するものであり、上記可動板１を、固定部５に外側トーションバー１１で揺動可能に軸支された枠状の外側可動板１２と、該外側可動板１２に外側トーションバー１１の軸線と直交する内側トーションバー１３で揺動可能に軸支された内側可動板１４とを備えた構成としている。
【００３３】
また、上記外側及び内側可動板１２，１４の表裏面でその周縁部（図３中破線で示す対応部位）に沿ってそれぞれ外側薄膜コイル１５Ａ，１５Ｂ及び内側薄膜コイル１６Ａ，１６Ｂを敷設し、図４（ａ）に示すように該内側薄膜コイル１６Ａ，１６Ｂの内側で内側可動板１４の表裏面に反射ミラー３Ａ，３Ｂを形成している。なお、図４（ｂ）に示すように外側及び内側薄膜コイル１５Ａ〜１６Ｂの上面にポリイミド等の絶縁層８を設け、さらに内側可動板１４の全面を覆って反射ミラー３Ａ，３Ｂを積層形成してもよい。または、同図（ｃ）に示すように内側可動板１４の全面に亘って絶縁層８を介して反射ミラー３Ａ，３Ｂを積層すると共に、外側可動板１２の絶縁層８上に外側反射ミラー２０Ａ，２０Ｂを積層してもよい。
【００３４】
また、図３に示すように外側薄膜コイル１５Ａ，１５Ｂは、それぞれ外側トーションバー１１を介して固定部５上に設けた電極端子部１８Ａ，１８Ｂに、また内側薄膜コイル１６Ａ，１６Ｂは、それぞれ内側及び外側トーションバー１３，１１を介して固定部５上に設けた電極端子部１９Ａ，１９Ｂに繋がっている。
【００３５】
さらに、上記外側トーションバー１１の軸方向に平行な外側可動板１２の対辺及び内側トーションバー１３の軸方向に平行な内側可動板１４の対辺に対応する固定部５の、例えば外側にそれぞれ静磁界発生手段４Ａ，４Ｂ，１７Ａ，１７Ｂを備えている。
【００３６】
このように構成したことにより、第２実施形態によれば、第１実施形態と同様に薄膜の残留圧縮応力や各薄膜コイルの発熱による熱応力が各可動板の表裏面でバランスし、各可動板の反りを抑制することができる。
【００３７】
また、図４（ｃ）に示すように内側可動板１４のみならず外側可動板１２の面を覆って外側反射ミラー２０Ａ，２０Ｂを設けた場合、内側可動板１４の位置を検出するための図示省略の内側用光源及び内側位置検出手段と、外側可動板１２の位置を検出するための図示省略の外側用光源及び外側位置検出手段とを備え、上記内側用光源の光ビームを内側可動板１４に設けた反射ミラー３Ａ（または３Ｂ）で反射して、その反射光ビームの受光位置に基づいて内側位置検出手段により検出して内側可動板１４の二次元の位置情報を得、上記外側用光源の光ビームを外側可動板１２に設けた反射ミラー２０Ａ（または２０Ｂ）で反射して、その反射光ビームの受光位置に基づいて外側位置検出手段により検出して外側可動板１２の一次元の位置情報を得て前記内側可動板の二次元位置情報から外側可動板の一次元位置情報を除いて内側可動板に作用する駆動力に基づく内側可動板の一次元位置情報を得る構成とすることにより、外側及び内側可動板１２，１４の各位置を分離して検出することができる。したがって、この検出結果に基づいて各可動板の駆動制御をそれぞれ個別に行うことができる。
【００３８】
次に、本発明に係る光走査装置の第３実施形態を図５及び図６を参照して説明する。なお、第１実施形態と同一の要素については同一符号を用いて示し、ここでは、第１実施形態と異なる部分についてのみ説明する。
図５は、第３実施形態の光走査装置の概略構成を示す分解斜視図である。この光走査装置は、光ビームを一次元走査するものであり、可動板１の表裏面で該可動板１の周縁部に沿って枠状の薄膜磁石２１Ａ，２１Ｂをそれぞれ設け、該薄膜磁石２１Ａ，２１Ｂの内側で可動板１の表裏面に反射ミラー３Ａ，３Ｂを形成すると共に、各薄膜磁石２１Ａ，２１Ｂ及び反射ミラー３Ａ，３Ｂの膜厚または材質若しくは形状を異ならせて可動板１の表裏面における応力をバランスさせている（図６（ａ）参照）。そして、上記薄膜磁石２１Ａ，２１Ｂは、磁化方向が同じ向きとなるように着磁されている。なお、図６（ｂ）に示すように薄膜磁石２１Ａ，２１Ｂを可動板１の全面に亘って設け、その上に反射ミラー３Ａ，３Ｂを積層して形成してもよい。
【００３９】
また、トーションバー６の軸方向に平行な可動板１の対辺に対向する固定部５の上面には、駆動コイル２２Ａ，２２Ｂを設けている。この駆動コイル２２Ａ，２２Ｂは、交流電流の通電により発生する磁界をトーションバー６の軸方向に平行な上記薄膜磁石２１Ａ，２１Ｂの対辺部に作用させて上記磁界と薄膜磁石２１Ａ，２１Ｂの静磁界との相互作用により可動板１を揺動させるものである。なお、駆動コイル２２Ａ，２２Ｂは、固定部１上ではなく、可動板１の下方でトーションバー６の軸方向に平行な薄膜磁石２１Ａ，２１Ｂの対辺部に対応する部位に互いに反対方向の磁界が発生するようにそれぞれ設けてもよく、または可動板の下方部位に上記薄膜磁石２１Ａ，２１Ｂに対して該薄膜磁石２１Ａ，２１Ｂの法線方向の磁界が作用するように駆動コイルを一つ設けてもよい。
【００４０】
このように構成したことにより、第３実施形態によれば、第１実施形態と同様に薄膜の残留圧縮応力よる反り力が可動板１の表裏面でバランスし、可動板１の反りを抑制することができる。また、可動板１の表裏面に薄膜磁石２１Ａ，２１Ｂを形成したことにより、第１実施形態におけるような薄膜コイル２Ａ，２Ｂによる熱応力の発生がなく、したがって熱応力による可動板１の反りを防止することができる。また、可動板１の表裏面に薄膜磁石２１Ａ，２１Ｂを設けたことにより、可動板１の一方の側だけに薄膜磁石を設けた従来の光走査装置と比べて同じ駆動電流を駆動コイルに供給したとき、略２倍の駆動力を得ることができる。
【００４１】
次に、本発明に係る光走査装置の第４実施形態を図７及び図８を参照して説明する。なお、第３実施形態と同一の要素については同一符号を用いて示し、ここでは、第３実施形態と異なる部分についてのみ説明する。
図７は、第４実施形態の光走査装置の概略構成を示す分解斜視図である。この光走査装置は、光ビームを二次元走査するものであり、上記可動板１を、固定部５に外側トーションバー１１で揺動可能に軸支された枠状の外側可動板１２と、該外側可動板１２に外側トーションバー１１の軸線と直交する内側トーションバー１３で揺動可能に軸支された内側可動板１４を備えた構成としている。
【００４２】
また、上記外側及び内側可動板１２，１４の表裏面でその周縁部に沿ってそれぞれ外側薄膜磁石２３Ａ，２３Ｂ及び内側薄膜磁石２１Ａ，２１Ｂを形成し、図８（ａ）に示すように該内側薄膜磁石２１Ａ，２１Ｂの内側で内側可動板１４の表裏面に反射ミラー３Ａ，３Ｂを形成している。なお、図８（ｂ）に示すように内側可動板１４の全面を覆って内側薄膜磁石２１Ａ，２１Ｂを形成しその上面に反射ミラー３Ａ，３Ｂを積層形成してもよい。または、同図（ｃ）に示すように内側薄膜磁石２１Ａ，２１Ｂ上に反射ミラー３Ａ，３Ｂを積層すると共に、外側薄膜磁石２３Ａ，２３Ｂ上に外側反射ミラー２０Ａ，２０Ｂを積層してもよい。
【００４３】
また、図７に示すように外側トーションバー１１の軸方向に平行な外側可動板１２の対辺に対向する固定部５の上面、及び内側トーションバー１３の軸方向に平行な内側可動板１４の対辺側方の固定部５上面には、駆動コイル２２Ａ，２２Ｂ及び２４Ａ，２４Ｂをそれぞれ設けている。なお、内側可動板１４だけに薄膜磁石と反射ミラーを形成する構成としてもよく、また、外側可動板１２だけに薄膜磁石を形成し、内側可動板１４だけに反射ミラーを形成する構成としてもよい。
【００４４】
このように構成したことにより、第４実施形態によれば、第３実施形態と同様に薄膜の残留圧縮応力よる反り力が可動板１の表裏面でバランスし、可動板１の反りを抑制することができる。また、可動板１の表裏面に薄膜磁石２１Ａ，２１Ｂを形成したことにより、熱応力の発生がなく、したがって熱応力による可動板１の反りを防止することができる。さらに、可動板１の表裏面に薄膜磁石２１Ａ，２１Ｂを設けたことにより、可動板１の一方の側だけに薄膜磁石を設けた従来の光走査装置に比べて同じ駆動電流を駆動コイル２２Ａ〜２４Ｂに供給したとき、略２倍の駆動力を得ることができる。さらにまた、第２実施形態と同様にして外側及び内側可動板１２，１４の位置情報を検出し、内側可動板１４の位置情報から外側可動板１４の位置情報を除けば、各可動板の位置を分離して検出することができ、該検出結果に基づいて各可動板の駆動制御をそれぞれ個別に行うことができる。
【００４５】
なお、上記第１〜４実施形態のいずれにおいても、本出願人が特開２００２−１３１６８５号公報に開示しているように、可動板１中央部と可動板１端部との間に、図９に斜線で示すような可動板１端部から上記可動板１中央部に伝達される可動板１中央部の変形要因を抑制する境界部１０を設けてもよい。この境界部１０は、可動板１を上下方向に貫通する孔であっても溝であってもよい。さらに、上記境界部１０が溝の場合には、該境界部１０を可動板１の表裏面に可動板１を挟んで同一位置に設けるとよい。または、可動板１の一方の面のみに設けてもよい。この場合は、薄膜コイル２Ａ，２Ｂ及び反射ミラー３Ａ，３Ｂの厚みや材質等を変えて可動板１の表裏面で応力が略等しくなるように調整するとよい。そして、境界部１０は、可動板１と異なる部材から成る、例えば断熱性等を有するポリイミド等の充填材で形成してもよい。以上により、可動板１の表裏面に形成された薄膜の残留圧縮応力による可動板１端部の反りの影響や薄膜コイル２Ａ，２Ｂに発生する熱が可動板１中央部に伝達されるのを抑制し、可動板１の反りを抑制することができる。
【００４６】
【発明の効果】
以上説明したように本発明の光走査装置によれば、半導体基板からなる平板状の可動板の表裏面に薄膜コイル及び反射ミラーをそれぞれ一対設けると共に、各薄膜コイル及び反射ミラーの膜厚または材質若しくは形状を異ならせて可動板の表裏面における応力をバランスさせることができる。したがって、可動板の反りを抑制することができ、光走査精度を向上することができる。
【００４７】
また、可動板の表裏面に薄膜コイルを一対設け、共に通電するようにしたことにより、薄膜コイルの発熱による熱応力が可動板の表裏面でバランスし、可動板の反りを抑制することができる。しかも、可動板両面に設けた薄膜コイルを駆動用に利用するので、両薄膜コイルを並列接続した場合は、従来と同一の駆動条件の下で各薄膜コイルにおける発熱を低減することができ、また直列接続した場合は、駆動力を２倍にすることができる。
【００４８】
また、半導体基板からなる平板状の可動板の表裏面に駆動コイルの磁界の作用により駆動力を発生する薄膜磁石及び反射ミラーをそれぞれ一対設けると共に、各薄膜磁石及び反射ミラーの膜厚または材質若しくは形状を異ならせて可動板の表裏面における応力をバランスさせることができる。したがって、可動板の反りを抑制することができ、光走査精度を向上する。
【００４９】
さらに、可動板の表裏面に薄膜磁石を一対設け、トーションバーの軸方向に平行な薄膜磁石の対辺部に駆動コイルにより磁界を作用させる構成としているので、可動板に熱応力が加わることがなく、熱応力による可動板の反りを防止することができる。しかも、この場合、両薄膜磁石を可動板の駆動力発生に使用することができるので、従来と同一の駆動条件の下で駆動力を２倍にすることができる。
【００５０】
さらにまた、各薄膜コイルまたは薄膜磁石及び反射ミラーを可動板の表裏面で同一位置に形成したことにより、応力の発生部位が可動板の表裏面で略一致し、該応力を相殺して可動板の反りをより効果的に抑制することができる。
【図面の簡単な説明】
【図１】本発明による光走査装置の第１実施形態の概略構成を示す分解斜視図である。
【図２】第１実施形態における駆動力発生部及び光学要素の形成例を示した断面図である。
【図３】本発明による光走査装置の第２実施形態の概略構成を示す分解斜視図である。
【図４】第２実施形態における駆動力発生部及び光学要素の形成例を示した断面図である。
【図５】本発明による光走査装置の第３実施形態の概略構成を示す分解斜視図である。
【図６】第３実施形態における駆動力発生部及び光学要素の形成例を示した断面図である。
【図７】本発明による光走査装置の第４実施形態の概略構成を示す分解斜視図である。
【図８】第４実施形態における駆動力発生部及び光学要素の形成例を示した断面図である。
【図９】可動板に設けた（Ａ）〜（Ｉ）境界部の種々の形状例を示す平面図である。
【符号の説明】
１…可動板
２Ａ，２Ｂ…薄膜コイル
３Ａ，３Ｂ…反射ミラー
４Ａ，４Ｂ，１７Ａ，１７Ｂ…静磁界発生手段
５…固定部
６…トーションバー
８…絶縁層
１０…境界部
１１…外側トーションバー
１２…外側可動板
１３…内側トーションバー
１４…内側可動板
１５…外側薄膜コイル
１６…内側薄膜コイル
２１Ａ，２１Ｂ…薄膜磁石
２２Ａ，２２Ｂ，２４Ａ，２４Ｂ…駆動コイル[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a planar optical scanning device formed integrally with a semiconductor substrate, and in particular, balances stresses generated on a movable plate on the front and back surfaces. Let The present invention relates to an optical scanning device that suppresses warping deformation of a movable plate and enables an improvement in driving force.
[0002]
[Prior art]
A conventional optical scanning device includes a movable plate that is pivotally supported by a torsion bar on a fixed portion of a semiconductor substrate and has a reflecting mirror formed at the center, and a thin film coil that is laid along the peripheral edge of the movable plate. The movable plate generates a driving force by the interaction between the static magnetic field and a current flowing through the thin film coil by applying a static magnetic field to the thin film coil portion in the vicinity of the opposite side of the movable plate parallel to the axial direction of the torsion bar. A thin film magnet formed on the movable plate, and driven to the fixed portion on the opposite side of the movable plate parallel to the axial direction of the torsion bar. There is a configuration in which a coil is formed and a movable force is oscillated by generating a driving force by the interaction between the electromagnetic field of the driving coil and the static magnetic field of the thin film magnet (see, for example, Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent No. 2722314
[0004]
[Problems to be solved by the invention]
However, in such a conventional optical scanning device, for example, in the former case, a thin film coil and a reflection mirror formed on the movable plate and a protective film such as polyimide formed for the purpose of protecting and insulating the thin film coil remain. In the latter case, the movable plate may be warped due to the compressive stress or the residual compressive stress of the thin film magnet and the reflecting mirror formed on the movable plate.
[0005]
In the case where the movable plate is provided with a thin film coil, heat is generated in the thin film coil by energization. Therefore, there is a possibility that the movable plate is warped due to the bimetal action resulting from the difference in thermal expansion coefficient between the thin film coil and reflection mirror material and the substrate material of the movable plate.
[0006]
Therefore, the present invention has been made paying attention to the above problems, and the stress generated on the movable plate is balanced between the front and back surfaces. Let An object of the present invention is to provide an optical scanning device that suppresses warping deformation of a movable plate and enables an improvement in driving force.
[0007]
[Means for Solving the Problems]
To this end, according to a first aspect of the present invention, a flat plate-like movable plate and a torsion bar that pivotally supports the movable plate so as to be swingable with respect to the fixed portion are integrated with the fixed portion made of a semiconductor substrate. A thin film coil that generates a magnetic field by energization along the peripheral edge of the movable plate, and a reflective mirror is provided on the movable plate, while the other side of the movable plate parallel to the axial direction of the torsion bar An optical scanning device comprising a static magnetic field generating means for applying a static magnetic field to a thin film coil portion, wherein a pair of the thin film coil and the reflection mirror are provided on the front and back surfaces of the movable plate. And balance the stress on the front and back surfaces of the movable plate by changing the film thickness, material, or shape of each thin film coil and reflecting mirror. It was.
[0008]
With this configuration, the front and back surfaces of a flat movable plate made of a semiconductor substrate Thin film coil and reflection mirror respectively Pair In addition, the film thickness, material, or shape of each thin film coil and reflecting mirror is changed to Balances stress and suppresses warping of movable plate. Thereby, the optical scanning accuracy is improved. Further, the driving force can be increased by using the pair of thin film coils for driving the movable plate.
[0009]
In this case, it is preferable that the pair of thin film coils is laid on the periphery of the movable plate, and the pair of reflection mirrors are formed inside the thin film coil. Alternatively, as described in claim 3, the pair of thin film coils may be laid on a movable plate, and the pair of reflection mirrors may be laminated on the upper surface of the thin film coil via an insulating layer.
[0010]
Further, in the case of the configuration of claim 4, the movable plate includes a frame-like outer movable plate pivotally supported on the fixed portion by an outer torsion bar, and the outer movable plate on the outer torsion bar. It consists of an inner movable plate pivotally supported by an inner torsion bar orthogonal to the axis, and a pair of outer thin film coils are laid on the front and rear surfaces of the outer movable plate, and on the peripheral portions of the front and rear surfaces of the inner movable plate. A pair of inner thin film coils are laid along the inner movable plate, and a pair of reflecting mirrors are provided on the front and back surfaces of the inner movable plate.
[0011]
In this case, it is preferable that the pair of inner thin film coils is laid on the inner movable plate peripheral edge and the pair of reflection mirrors are formed inside the inner thin film coil. Alternatively, the pair of inner thin film coils may be laid on the inner movable plate as in claim 6, and the pair of reflection mirrors may be laminated on the upper surface of the inner thin film coil via an insulating layer. As described above, a pair of reflecting mirrors may be laminated on the upper surfaces of the pair of outer thin film coils via an insulating layer.
[0012]
Further, a pair of thin film coils laid on the front and back surfaces of the movable plate as in claim 8 may be connected in series, or a pair of thin film coils laid on the front and back surfaces of the movable plate as in claim 9 are connected in parallel. May be.
[0013]
According to a second aspect of the present invention, a flat movable plate and a torsion bar that pivotally supports the movable plate with respect to the fixed portion are integrally formed on the fixed portion made of a semiconductor substrate. The movable plate is provided with a thin film magnet that generates a static magnetic field and a reflection mirror, while a magnetic field generated by energization is applied to the thin film magnet portion on the opposite side of the movable plate that is parallel to the axial direction of the torsion bar. An optical scanning device comprising a drive coil to be provided, wherein a pair of the thin film magnet and the reflection mirror are provided on the front and back surfaces of the movable plate, respectively. And balance the stress on the front and back surfaces of the movable plate by changing the film thickness, material, or shape of each thin film magnet and reflecting mirror. It was.
[0014]
With this configuration, the front and back surfaces of a flat movable plate made of a semiconductor substrate Thin film magnet and reflecting mirror respectively Pair In addition, the film thickness, material, or shape of each thin film magnet and reflecting mirror is changed to Balances stress and suppresses warping of movable plate. Thereby, the optical scanning accuracy is improved. Further, the driving force can be increased by using the pair of thin film magnets for driving the movable plate.
[0015]
In this case, as in the eleventh aspect, the pair of thin film magnets may be formed on the periphery of the movable plate, and the pair of reflection mirrors may be formed inside the thin film magnet. Alternatively, as described in claim 12, the pair of thin film magnets may be formed on a movable plate, and the pair of reflection mirrors may be laminated on the upper surface of the thin film magnet.
[0016]
Further, in the case of the structure of claim 13, the movable plate includes a frame-shaped outer movable plate pivotally supported on the fixed portion by an outer torsion bar, and the outer movable plate on the outer torsion bar. The inner movable plate is pivotally supported by an inner torsion bar orthogonal to the axis, and at least a pair of a thin film magnet and a reflecting mirror that generate a static magnetic field on the front and back surfaces of the inner movable plate are provided. .
[0017]
In this case, it is preferable to form the pair of thin film magnets on the inner movable plate peripheral edge as in claim 14 and to form the pair of reflection mirrors on the inner side of the inner thin film magnet. Alternatively, the pair of thin film magnets may be formed on the inner movable plate as in claim 15, and the pair of reflecting mirrors may be laminated on the upper surface of the inner thin film magnet. A pair of thin film magnets may be formed on the front and back surfaces of the plate. Further, a pair of reflecting mirrors may be formed on the top surfaces of the pair of thin film magnets formed on the front and back surfaces of the outer movable plate as in the seventeenth aspect.
[0018]
Further, a boundary part for suppressing a deformation factor of the movable plate central part transmitted from the movable plate end part to the movable plate central part between the central part of the movable plate and the movable plate end part as in claim 18. May be provided. Or, the deformation factor of the inner movable plate central portion transmitted from the inner movable plate end portion to the inner movable plate central portion between the inner movable plate end portion and the inner movable plate end portion as in claim 19. You may provide the boundary part which suppresses.
[0019]
Furthermore, as in the twentieth aspect, it is preferable that the thin film coils and the reflection mirror and the boundary portion or the thin film magnets and the reflection mirror and the boundary portion are formed at the same position on the front and back surfaces of the movable plates.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is an exploded perspective view showing a schematic configuration of a first embodiment of an optical scanning device according to the present invention.
In FIG. 1, the optical scanning device of the first embodiment is a one-dimensional optical scanning device formed integrally with a semiconductor substrate, and includes a movable plate 1, thin film coils 2A and 2B, and reflection mirrors 3A and 3B. And static magnetic field generating means 4A and 4B.
[0022]
The movable plate 1 is pivotally supported by a frame-like fixed portion 5 so as to be swingable by a torsion bar 6. The semiconductor substrate is anisotropically etched in the thickness direction thereof to fix the fixed portion 5 and the torsion bar 6. It is formed integrally. Also, a pair of reflection mirrors 3A and 3B, which will be described later, are provided on the front and back surfaces of the movable plate 1, and a light beam is reflected by the reflection mirror 3A (or 3B) as the movable plate 1 is swung to one-dimensionally. I'm trying to scan. In addition, if a semiconductor substrate is processed by applying semiconductor micromachining technology Whatever For example, it is a silicon substrate or a plastic substrate.
[0023]
Thin film coils 2 </ b> A and 2 </ b> B are laid on the front and back surfaces of the movable plate 1 along the peripheral edge of the movable plate 1, respectively. The thin film coils 2A and 2B are formed by static magnetic field generated from static magnetic field generating means 4A and 4B, which will be described later, by the current flowing through the thin film coils 2A and 2B in the vicinity of the opposite side of the movable plate 1 parallel to the axial direction of the torsion bar 6. Is applied to generate a driving force on the opposite side of the movable plate 1 to swing the movable plate 1, and is formed by etching a conductive thin film such as aluminum by a semiconductor manufacturing process. Then, both end portions of the thin film coils 2A and 2B are connected to electrode terminal portions 7A and 7B formed on the fixed portion 5 through the torsion bar 6, respectively, so that a drive current can be supplied from a control circuit (not shown). Yes. 1 shows a configuration in which the thin film coils 2A and 2B are connected in parallel. For example, the right electrode terminal portion 7A in FIG. 1 and the left electrode terminal portion 7B in FIG. 2A and 2B may be connected in series.
[0024]
Reflecting mirrors 3A and 3B are provided inside the thin film coils 2A and 2B on the front and back surfaces of the movable plate 1 as shown in FIG. The reflection mirror 3A (or 3B) reflects an incident light beam, and is formed, for example, by forming a reflection film made of aluminum or the like by vacuum deposition or sputtering. Alternatively, as shown in FIG. 2B, the reflecting mirrors 3A and 3B may be formed so as to cover the entire surface of the movable plate 1 through an insulating layer 8 such as polyimide provided on the thin film coils 2A and 2B. The thin film coils 2A and 2B and the reflection mirrors 3A and 3B are formed at the same position on the front and back surfaces of the movable plate 1.
[0025]
Then, on the opposite side of the movable plate 1 parallel to the axial direction of the torsion bar 6, for example, on the upper surface portion of the fixed portion 5, the pair of static magnetic field generating means 4 </ b> A and 4 </ b> B are connected to each other with the movable plate 1 in between. Opposite magnetic poles are provided facing each other. The static magnetic field generating means 4A and 4B act on the thin film coils 2A and 2B in the vicinity of the opposite side of the movable plate 1 by applying a component parallel to the movable plate 1 and perpendicular to the thin film coils 2A and 2B. , 2B, Lorentz force is generated by interaction with the current flowing through 2B, for example, a permanent magnet. Note that the static magnetic field generating means 4A and 4B may be arranged not on the upper surface portion of the fixed portion 5 but on the outside thereof.
[0026]
Next, the operation of the first embodiment of the present invention will be described.
First, drive currents are respectively supplied to the parallel-connected thin film coils 2A and 2B shown in FIG. 1 from a control circuit (not shown) via the electrode terminal portions 7A and 7B. In this case, the portions of the thin-film coils 2A and 2B in the vicinity of the opposite side of the movable plate 1 parallel to the axial direction of the torsion bar 6 are subjected to a static magnetic field by the static magnetic field generating means 4A and 4B arranged to face the portions. Is working. Therefore, the static magnetic field component parallel to the movable plate 1 and perpendicular to the above-mentioned portions of the thin-film coils 2A and 2B among the static magnetic fields interacts with the current flowing through the portions of the thin-film coils 2A and 2B to interact with the thin-film coils 2A and 2B. A Lorentz force is generated in the portion of 2B, and the movable plate 1 is swung. As the movable plate 1 swings, the light beam is one-dimensionally scanned by the reflection mirror 3A (or 3B) formed on the movable plate 1.
[0027]
When the movable plate 1 is driven, the same amount of drive current flows through the thin film coils 2A and 2B provided on the front and back surfaces of the movable plate 1. Accordingly, the amount of heat generated in the thin film coils 2A and 2B is equal. Moreover, since the thin film coils 2A and 2B are formed at the same position on the front and back surfaces of the movable plate 1, the thermal stress generated on the front and back surfaces of the movable plate 1 is balanced and the warpage of the movable plate 1 is suppressed.
[0028]
Further, since the thin film coils 2A and 2B and the reflection mirrors 3A and 3B are formed on the front and back surfaces of the movable plate 1 at the same position on the front and back surfaces of the movable plate 1, the thin film coils 2A and 2B and the reflection mirrors 3A and 3B are formed. The warping force due to the residual compressive stress of the thin film is balanced at each part of the front and back surfaces of the movable plate 1 to suppress the warp of the movable plate 1. When the residual compressive stress of the thin film varies depending on the thin film formation conditions Therefore, in the first embodiment Adjusts the thickness, material, or shape of the thin film coils 2A, 2B, the reflecting mirrors 3A, 3B, and the insulating layer 8 so as to balance the stresses on the front and back surfaces of the movable plate 1. Have The
[0029]
As described above, according to the first embodiment, the thin film coils 2A and 2B and the reflection mirrors 3A and 3B are formed on the front and back surfaces of the movable plate 1, respectively. At the same time, the thin film coils 2A and 2B and the reflecting mirrors 3A and 3B are made different in film thickness, material or shape to balance the residual compressive stress of the thin film on the front and back surfaces of the movable plate 1. Accordingly, the warping force due to the residual compressive stress of the thin film is balanced on the front and back surfaces of the movable plate 1, and the occurrence of the warp of the movable plate 1 can be suppressed. Further, by forming the thin film coils 2A and 2B and the reflection mirrors 3A and 3B at the same position on the front and back surfaces of the movable plate 1, the portions where the residual compressive stress of the thin film is substantially matched on the front and back surfaces of the movable plate 1, The warp of the movable plate 1 can be more effectively suppressed by canceling the stress.
[0030]
Further, since the movable plate 1 is swung by energizing both the thin film coils 2A and 2B, the heat generated in the thin film coils 2A and 2B becomes substantially equal on the front and back surfaces of the movable plate 1, and this heat generation The thermal stress due to the balance between the front and back surfaces of the movable plate 1 can suppress the occurrence of warpage. Thereby, the optical scanning accuracy can be improved.
[0031]
Further, the thin film coils 2A and 2B formed on the front and back surfaces of the movable plate 1 are connected in parallel, so that the driving force is increased as compared with the conventional optical scanning device in which the thin film coil is provided only on one side of the movable plate 1. When it is the same, the value of the current flowing through each thin film coil 2A, 2B is halved, and heat generation in the thin film coils 2A, 2B can be reduced. Needless to say, if the same current value is supplied to the thin film coils 2A and 2B on the front and back surfaces of the movable plate 1, a double driving force can be obtained. Further, when the thin film coils 2A and 2B are connected in series, a driving force approximately twice as large as that of the conventional optical scanning device can be obtained with the same current value.
[0032]
Next, a second embodiment of the optical scanning device according to the present invention will be described with reference to FIGS. Note that the same elements as those in the first embodiment are denoted by the same reference numerals, and only portions different from those in the first embodiment will be described here.
FIG. 3 is an exploded perspective view showing a schematic configuration of the optical scanning device of the second embodiment. This optical scanning device performs two-dimensional scanning of a light beam. The movable plate 1 includes a frame-shaped outer movable plate 12 pivotally supported on a fixed portion 5 by an outer torsion bar 11, and the movable plate 1. The outer movable plate 12 is provided with an inner movable plate 14 that is pivotally supported by an inner torsion bar 13 orthogonal to the axis of the outer torsion bar 11.
[0033]
Further, the outer thin film coils 15A and 15B and the inner thin film coils 16A and 16B are laid on the front and back surfaces of the outer and inner movable plates 12 and 14 along their peripheral portions (corresponding portions indicated by broken lines in FIG. 3), respectively. As shown in FIG. 4A, reflecting mirrors 3A and 3B are formed on the front and back surfaces of the inner movable plate 14 inside the inner thin film coils 16A and 16B. As shown in FIG. 4B, an insulating layer 8 such as polyimide is provided on the upper surfaces of the outer and inner thin film coils 15A to 16B, and the reflecting mirrors 3A and 3B are laminated to cover the entire surface of the inner movable plate 14. May be. Alternatively, as shown in FIG. 3C, the reflection mirrors 3A and 3B are laminated over the entire surface of the inner movable plate 14 via the insulating layer 8, and the outer reflection mirror 20A is formed on the insulating layer 8 of the outer movable plate 12. 20B may be laminated.
[0034]
Further, as shown in FIG. 3, the outer thin film coils 15A and 15B are respectively connected to the electrode terminal portions 18A and 18B provided on the fixing portion 5 via the outer torsion bar 11, and the inner thin film coils 16A and 16B are respectively connected to the inner side. And it is connected to the electrode terminal portions 19A and 19B provided on the fixed portion 5 via the outer torsion bars 13 and 11.
[0035]
Further, for example, static magnetic fields on the outer sides of the fixed portions 5 corresponding to the opposite sides of the outer movable plate 12 parallel to the axial direction of the outer torsion bar 11 and the opposite sides of the inner movable plate 14 parallel to the axial direction of the inner torsion bar 13, respectively. Generation means 4A, 4B, 17A, 17B are provided.
[0036]
With this configuration, according to the second embodiment, similar to the first embodiment, the residual compressive stress of the thin film and the thermal stress due to heat generation of each thin film coil are balanced on the front and back surfaces of each movable plate, and each movable Warpage of the plate can be suppressed.
[0037]
4C, when the outer reflecting mirrors 20A and 20B are provided so as to cover not only the inner movable plate 14 but also the outer movable plate 12, the position for detecting the position of the inner movable plate 14 is illustrated. An inner light source and inner position detection means (not shown) and an outer light source and outer position detection means (not shown) for detecting the position of the outer movable plate 12 are provided, and the inner movable plate 14 transmits the light beam of the inner light source. Is reflected by the reflecting mirror 3A (or 3B) provided on the light source, and is detected by the inner position detecting means based on the light receiving position of the reflected light beam to obtain two-dimensional position information of the inner movable plate 14, and the outer light source. Is reflected by the reflecting mirror 20A (or 20B) provided on the outer movable plate 12, and is detected by the outer position detecting means on the basis of the light receiving position of the reflected light beam and is one-dimensional position of the outer movable plate 12. Affection By obtaining the one-dimensional position information of the inner movable plate based on the driving force acting on the inner movable plate by removing the one-dimensional position information of the outer movable plate from the two-dimensional position information of the inner movable plate, The positions of the outer and inner movable plates 12 and 14 can be detected separately. Therefore, drive control of each movable plate can be performed individually based on the detection result.
[0038]
Next, a third embodiment of the optical scanning device according to the present invention will be described with reference to FIGS. Note that the same elements as those in the first embodiment are denoted by the same reference numerals, and only portions different from those in the first embodiment will be described here.
FIG. 5 is an exploded perspective view showing a schematic configuration of the optical scanning device of the third embodiment. This optical scanning device performs one-dimensional scanning of a light beam, and is provided with frame-shaped thin film magnets 21A and 21B along the periphery of the movable plate 1 on the front and back surfaces of the movable plate 1, respectively. , 21B, reflection mirrors 3A and 3B are formed on the front and back surfaces of the movable plate 1 At the same time, the thin film magnets 21A and 21B and the reflecting mirrors 3A and 3B are made different in film thickness, material or shape to balance the stress on the front and back surfaces of the movable plate 1. (See FIG. 6A). The thin film magnets 21A and 21B are magnetized so that the magnetization directions are the same. 6B, the thin film magnets 21A and 21B may be provided over the entire surface of the movable plate 1, and the reflection mirrors 3A and 3B may be stacked thereon.
[0039]
Drive coils 22A and 22B are provided on the upper surface of the fixed portion 5 facing the opposite side of the movable plate 1 parallel to the axial direction of the torsion bar 6. The drive coils 22A and 22B act on the opposite sides of the thin film magnets 21A and 21B parallel to the axial direction of the torsion bar 6 by applying a magnetic field generated by energization of an alternating current to the magnetic field and the static magnetic fields of the thin film magnets 21A and 21B. The movable plate 1 is swung by the interaction. Note that the drive coils 22A and 22B are not on the fixed portion 1 but have magnetic fields in opposite directions at portions corresponding to the opposite sides of the thin film magnets 21A and 21B parallel to the axial direction of the torsion bar 6 below the movable plate 1. Each drive coil may be provided so as to be generated, or one drive coil is provided at a lower part of the movable plate so that a magnetic field in the normal direction of the thin film magnets 21A and 21B acts on the thin film magnets 21A and 21B. Also good.
[0040]
With this configuration, according to the third embodiment, the warping force due to the residual compressive stress of the thin film is balanced on the front and back surfaces of the movable plate 1 and the warpage of the movable plate 1 is suppressed as in the first embodiment. be able to. In addition, since the thin film magnets 21A and 21B are formed on the front and back surfaces of the movable plate 1, there is no generation of thermal stress due to the thin film coils 2A and 2B as in the first embodiment. Can be prevented. Further, by providing the thin film magnets 21A and 21B on the front and back surfaces of the movable plate 1, the same drive current is supplied to the drive coil as compared with the conventional optical scanning device in which the thin film magnet is provided only on one side of the movable plate 1. When this is done, approximately twice the driving force can be obtained.
[0041]
Next, a fourth embodiment of the optical scanning device according to the present invention will be described with reference to FIGS. Note that the same elements as those of the third embodiment are denoted by the same reference numerals, and only portions different from those of the third embodiment will be described here.
FIG. 7 is an exploded perspective view showing a schematic configuration of the optical scanning device of the fourth embodiment. This optical scanning device performs two-dimensional scanning of a light beam. The movable plate 1 includes a frame-shaped outer movable plate 12 pivotally supported on a fixed portion 5 by an outer torsion bar 11, and the movable plate 1. The outer movable plate 12 includes an inner movable plate 14 that is pivotally supported by an inner torsion bar 13 that is orthogonal to the axis of the outer torsion bar 11.
[0042]
Further, outer thin film magnets 23A and 23B and inner thin film magnets 21A and 21B are formed on the front and rear surfaces of the outer and inner movable plates 12 and 14 along the peripheral edges thereof, respectively, as shown in FIG. 8 (a). Reflective mirrors 3A and 3B are formed on the front and back surfaces of the inner movable plate 14 inside the thin film magnets 21A and 21B. As shown in FIG. 8B, the inner thin film magnets 21A and 21B may be formed so as to cover the entire surface of the inner movable plate 14, and the reflection mirrors 3A and 3B may be laminated on the upper surface. Alternatively, as shown in FIG. 5C, the reflection mirrors 3A and 3B may be laminated on the inner thin film magnets 21A and 21B, and the outer reflection mirrors 20A and 20B may be laminated on the outer thin film magnets 23A and 23B.
[0043]
Further, as shown in FIG. 7, the upper surface of the fixed portion 5 facing the opposite side of the outer movable plate 12 parallel to the axial direction of the outer torsion bar 11 and the opposite side of the inner movable plate 14 parallel to the axial direction of the inner torsion bar 13. Drive coils 22A and 22B and 24A and 24B are provided on the upper surface of the side fixing portion 5, respectively. The thin film magnet and the reflection mirror may be formed only on the inner movable plate 14, or the thin film magnet may be formed only on the outer movable plate 12 and the reflection mirror may be formed only on the inner movable plate 14. .
[0044]
With this configuration, according to the fourth embodiment, the warping force due to the residual compressive stress of the thin film is balanced on the front and back surfaces of the movable plate 1 and the warpage of the movable plate 1 is suppressed as in the third embodiment. be able to. In addition, since the thin film magnets 21A and 21B are formed on the front and back surfaces of the movable plate 1, no thermal stress is generated, and therefore warpage of the movable plate 1 due to the thermal stress can be prevented. Further, by providing the thin film magnets 21A and 21B on the front and back surfaces of the movable plate 1, the same drive current as that of the conventional optical scanning device in which the thin film magnet is provided only on one side of the movable plate 1 can be obtained. When supplied to 24B, approximately double driving force can be obtained. Furthermore, as in the second embodiment, the position information of the outer and inner movable plates 12 and 14 is detected, and the position information of the outer movable plate 14 is removed from the position information of the inner movable plate 14. Can be detected separately, and drive control of each movable plate can be performed individually based on the detection result.
[0045]
In any of the first to fourth embodiments, as disclosed in Japanese Patent Application Laid-Open No. 2002-131585, the applicant of the present invention has a figure between the central portion of the movable plate 1 and the end portion of the movable plate 1. 9 may be provided with a boundary portion 10 that suppresses a deformation factor of the central portion of the movable plate 1 that is transmitted from the end portion of the movable plate 1 to the central portion of the movable plate 1 as indicated by hatching. The boundary portion 10 may be a hole or a groove penetrating the movable plate 1 in the vertical direction. Furthermore, when the boundary portion 10 is a groove, the boundary portion 10 may be provided at the same position with the movable plate 1 sandwiched between the front and back surfaces of the movable plate 1. Alternatively, it may be provided only on one surface of the movable plate 1. In this case, the thicknesses and materials of the thin film coils 2A and 2B and the reflecting mirrors 3A and 3B may be changed so that the stresses are approximately equal on the front and back surfaces of the movable plate 1. The boundary portion 10 may be formed of a filler made of a material different from that of the movable plate 1, such as polyimide having heat insulating properties. As described above, the influence of the warp of the movable plate 1 end due to the residual compressive stress of the thin film formed on the front and back surfaces of the movable plate 1 and the heat generated in the thin film coils 2A and 2B are transmitted to the central portion of the movable plate 1. It can suppress and the curvature of the movable plate 1 can be suppressed.
[0046]
【The invention's effect】
As described above, according to the optical scanning device of the present invention, the front and back surfaces of the flat movable plate made of a semiconductor substrate are used. Thin film coil and reflection mirror respectively Pair At the same time, the film thickness, material, or shape of each thin film coil and reflecting mirror is changed to Stress can be balanced. Therefore, the warp of the movable plate can be suppressed, and the optical scanning accuracy can be improved.
[0047]
Further, by providing a pair of thin film coils on the front and back surfaces of the movable plate and energizing them together, the thermal stress due to the heat generated by the thin film coil is balanced on the front and back surfaces of the movable plate, and the warp of the movable plate can be suppressed. . Moreover, since the thin film coils provided on both sides of the movable plate are used for driving, when both thin film coils are connected in parallel, the heat generation in each thin film coil can be reduced under the same driving conditions as before, and When connected in series, the driving force can be doubled.
[0048]
In addition, a thin film magnet and a reflecting mirror that generate a driving force by the action of the magnetic field of the driving coil are provided on the front and back surfaces of a flat movable plate made of a semiconductor substrate. Respectively Pair In addition, the film thickness, material, or shape of each thin film magnet and the reflecting mirror is varied so that Stress can be balanced. Therefore, the warp of the movable plate can be suppressed, and the optical scanning accuracy is improved.
[0049]
In addition, a pair of thin film magnets are provided on the front and back surfaces of the movable plate, and a magnetic field is applied to the opposite sides of the thin film magnet parallel to the axial direction of the torsion bar by the drive coil, so that no thermal stress is applied to the movable plate. Further, warpage of the movable plate due to thermal stress can be prevented. In addition, in this case, both thin film magnets can be used for generating the driving force of the movable plate, so that the driving force can be doubled under the same driving conditions as in the prior art.
[0050]
Furthermore, by forming each thin film coil or thin film magnet and reflecting mirror at the same position on the front and back surfaces of the movable plate, the stress generation sites are substantially matched on the front and back surfaces of the movable plate, and the movable plate cancels the stress. Can be more effectively suppressed.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing a schematic configuration of a first embodiment of an optical scanning device according to the present invention.
FIG. 2 is a cross-sectional view showing an example of formation of a driving force generator and optical elements in the first embodiment.
FIG. 3 is an exploded perspective view showing a schematic configuration of a second embodiment of an optical scanning device according to the present invention.
FIG. 4 is a cross-sectional view showing an example of formation of a driving force generator and optical elements in a second embodiment.
FIG. 5 is an exploded perspective view showing a schematic configuration of a third embodiment of an optical scanning device according to the present invention.
FIG. 6 is a cross-sectional view showing an example of formation of a driving force generator and optical elements in a third embodiment.
FIG. 7 is an exploded perspective view showing a schematic configuration of a fourth embodiment of an optical scanning device according to the present invention.
FIG. 8 is a cross-sectional view showing an example of formation of a driving force generator and optical elements in a fourth embodiment.
FIG. 9 is a plan view showing various shape examples of the boundary portion (A) to (I) provided on the movable plate.
[Explanation of symbols]
1 ... Movable plate
2A, 2B ... Thin film coil
3A, 3B ... Reflection mirror
4A, 4B, 17A, 17B ... Static magnetic field generating means
5 ... fixed part
6 ... Torsion bar
8 ... Insulating layer
10 ... Boundary part
11 ... Outer torsion bar
12 ... Outside movable plate
13 ... Inner torsion bar
14 ... Inside movable plate
15 ... Outer thin film coil
16 ... Inner thin film coil
21A, 21B ... Thin film magnet
22A, 22B, 24A, 24B ... drive coil

Claims

A flat plate-like movable plate and a torsion bar that pivotably supports the movable plate with respect to the fixed portion are integrally formed on the fixed portion made of a semiconductor substrate, and energized along the peripheral edge of the movable plate. Static magnetic field generation that applies a static magnetic field to the thin film coil portion on the opposite side of the movable plate that is parallel to the axial direction of the torsion bar, while a thin film coil that generates a magnetic field is laid and a reflective mirror is provided on the movable plate An optical scanning device comprising a means,
The thin film coil and the pair reflection mirrors each provided Rutotomoni on the front and rear surfaces of the movable plate, said balance the stresses in the front and back surfaces of the thin film coil and the thickness of the reflective mirror or the material or shape by varying the movable plate An optical scanning device characterized by that.

2. The optical scanning device according to claim 1, wherein the pair of thin film coils is laid on the periphery of the movable plate, and the pair of reflection mirrors is formed inside the thin film coil.

2. The optical scanning device according to claim 1, wherein the pair of thin film coils are laid on a movable plate, and the pair of reflection mirrors are stacked on an upper surface of the thin film coil via an insulating layer.

The movable plate is slidably supported by a frame-shaped outer movable plate pivotally supported by an outer torsion bar at a fixed portion, and an inner torsion bar orthogonal to the axis of the outer torsion bar. A pair of outer thin film coils laid on the front and back surfaces of the outer movable plate, and a pair of inner thin film coils laid along the peripheral edge of the front and back surfaces of the inner movable plate, The optical scanning device according to claim 1, wherein a pair of reflecting mirrors are provided on the front and back surfaces of the inner movable plate.

5. The optical scanning device according to claim 4, wherein the pair of inner thin film coils is laid on a peripheral edge of the inner movable plate, and the pair of reflection mirrors are formed inside the inner thin film coil.

5. The optical scanning device according to claim 4, wherein the pair of inner thin film coils are laid on an inner movable plate, and the pair of reflection mirrors are stacked on an upper surface of the inner thin film coil via an insulating layer.

5. The optical scanning device according to claim 4, wherein a pair of reflecting mirrors are laminated on the upper surfaces of the pair of outer thin film coils via an insulating layer.

The optical scanning device according to any one of claims 1 to 7, wherein a pair of thin film coils laid on the front and back surfaces of the movable plate are connected in series.

The optical scanning device according to claim 1, wherein a pair of thin film coils laid on the front and back surfaces of the movable plate are connected in parallel.

A thin film that integrally forms a flat movable plate and a torsion bar that pivotably supports the movable plate with respect to the fixed portion on a fixed portion made of a semiconductor substrate, and generates a static magnetic field on the movable plate. An optical scanning device comprising a driving coil for providing a magnetic field generated by energization to a thin film magnet portion on the opposite side of the movable plate parallel to the axial direction of the torsion bar while providing a magnet and a reflection mirror There,
The thin film magnet and the pair reflection mirrors each provided Rutotomoni on the front and rear surfaces of the movable plate, said balance the stresses in the front and back surfaces of the thin magnets and thickness of the reflective mirror or the material or shape by varying the movable plate An optical scanning device characterized by that.

The optical scanning device according to claim 10, wherein the pair of thin film magnets are formed on a peripheral edge of the movable plate, and the pair of reflecting mirrors are formed inside the thin film magnet.

The optical scanning device according to claim 10, wherein the pair of thin film magnets are formed on a movable plate, and the pair of reflection mirrors are stacked on an upper surface of the thin film magnet.

The movable plate is slidably supported by a frame-shaped outer movable plate pivotally supported by an outer torsion bar at a fixed portion, and an inner torsion bar orthogonal to the axis of the outer torsion bar. 11. The light according to claim 10, comprising a pair of thin film magnets and reflecting mirrors each generating a static magnetic field at least on the front and back surfaces of the inner movable plate. Scanning device.

14. The optical scanning device according to claim 13, wherein the pair of thin film magnets are formed on a peripheral edge portion of the inner movable plate, and the pair of reflecting mirrors are formed on the inner side of the inner thin film magnet.

The optical scanning device according to claim 13, wherein the pair of thin film magnets are formed on an inner movable plate, and the pair of reflecting mirrors are stacked on an upper surface of the inner thin film magnet.

16. The optical scanning device according to claim 13, wherein a pair of thin film magnets are formed on the front and back surfaces of the outer movable plate.

17. The optical scanning device according to claim 16, wherein a pair of reflecting mirrors are formed on the top surfaces of the pair of thin film magnets formed on the front and back surfaces of the outer movable plate.

A boundary portion is provided between the central portion of the movable plate and the movable plate end portion to suppress a deformation factor of the movable plate central portion transmitted from the movable plate end portion to the movable plate central portion. The optical scanning device according to claim 1.

A boundary portion is provided between the central portion of the inner movable plate and the inner movable plate end portion to suppress a deformation factor of the inner movable plate central portion transmitted from the inner movable plate end portion to the inner movable plate central portion. The optical scanning device according to any one of claims 4 to 9, and 13 to 17.

Each said thin-film coil and reflection mirror, and a boundary part, or each said thin-film magnet, reflection mirror, and a boundary part were formed in the same position of the front and back of each said movable plate, The any one of Claims 1-19 characterized by the above-mentioned. The optical scanning device according to one.