JP4700869B2 - Optical unit assembly method and optical unit - Google Patents

Description

【００１６】
【数２】

【００１７】
ここで、任意の点における磁束密度Ｂは、ＢｎとＢｓを合成したものになり、（６）式で示される。
Ｂ＝Ｂｎ＋Ｂｓ ・・・（６）
上記（５）式及び（６）式において、Ｂｒは永久磁石の残留磁束密度ｘ，ｙ，ｚは永久磁石の周りの空間の任意の点を表す座標、ｌは永久磁石のＮ極面とＳ極面との距離、ｄは各極面の半径である。例えば、半径１ｍｍ，高さ１ｍｍ，残留磁束密度０．８５ＴのＳｍ−Ｃｏ永久磁石ＤＩＡＮＥＴ ＤＭ−１８（商品名、セイコー電子部品製）を用いて、図１２に示すように配置した永久磁石の表面に垂直な面ａの磁束密度分布を計算した結果は図１２に示される。
【００１８】
図１１のように配置した場合には、磁石間の空間は、略０．３Ｔ以上の磁束密度となっている。次に、可動板５の変位量の計算結果について説明する。可動板５に形成する平面コイル７の幅を１００μｍ、巻数を１４、可動板５の厚さを２０μｍとし、トーションバー６の半径を２５μｍ，長さを１ｍｍ、可動板５の幅を４ｍｍ、長さを５ｍｍとして、（２）式と（３）式から求めた。尚、磁束密度は、前述の磁束密度分布計算で得られた０．３Ｔが使用される。
【００１９】
その結果として、図１３（Ａ）及び図１３（Ｂ）に示すように、電流１．５ｍＡで２度の変位角が得られることがわかる。尚、図１３（Ｃ）は電流と発生する熱量Ｑとの関係を示すもので、この時の単位面積当たりの発生熱量は１３μワット／ｃｍ^２となった。次に、発熱量と放熱の関係について説明する。発熱量はコイルの抵抗で発生するジュール熱であり、従って、単位時間当たりに発生する熱量Ｑは下記の（７）式によって表される。
Ｑ＝ｉ２×Ｒ …（７）
【００２０】
ここで、ｉはコイルに流れる電流、Ｒはコイルの抵抗である。発熱量対流による放熱量Ｑｃ は下記の（８）式で表される。
Ｑｃ＝ｈＳΔＴ …（８）
【００２１】
ここで、ｈは熱伝達係数（空気は５×１０^−３〜５×１０^−２〔ワット／ｃｍ^２℃〕）、Ｓは素子の表面積、ΔＴは素子表面と空気との温度差である。
【００２２】
発熱部となる可動板の面積を２０ｍｍ^２（４×５）とすると、（８）式は、
Ｑｃ＝１．０×ΔＴ〔ｍワット／℃〕 …（８）′
となり、数十μワット／ｃｍ^２程度の発熱量ならば素子の温度上昇の問題は無視できることがわかる。尚、参考まで、輻射による放熱量Ｑｒは下記の（９）式で表される。
Ｑｒ＝εＳσＴ^４ …（９）
【００２３】
ここで、εは輻射率（黒体はε＝１Ｄ 一般にε＜１）、Ｓは素子の表面積、σはステファンボルツマン定数（π２ｋ^４／６０ｈ^３ｃ^２）、Ｔは素子の表面温度である。また、トーションバーからの伝導による放熱量Ｑａは下記の（１０）式で表される。
Ｑａ＝２λ（Ｓ／ｌ_１）ΔＴ …（１０）
【００２４】
ここで、λは熱伝導率（シリコンは８４ワット／ｍＫ）、Ｓはトーションバーの断面積、ｌ_１ はトーションバーの長さ、ΔＴはトーションバーの両端の温度差である。トーションバーの半径を２５μｍ、長さを１ｍｍとすると（１０）式は、
Ｑａ＝０．１×ΔＴ〔ｍワット／℃〕 …（１０）′
となる。
【００２５】
次にトーションバーの可動板自重による撓みと、電磁力による可動板の撓みについて説明する。図１４にこれらの計算モデルを示す。トーションバーの長さをｌ１ 、トーションバーの幅をｂ、可動板の重さをｆ、可動板の厚さをｔ、可動板の幅をＷ、可動板の長さをＬ１ とすると、トーションバーの撓み量ΔＹは、片持ち梁の撓み量の計算方法を用いて、下記の（１１）式のようになる。
ΔＹ＝（１／２）（４ｌ_１ ^３ｆ／Ｅｂｔ^３） …（１１）
【００２６】
ここで、Ｅはシリコンのヤング率である。
【００２７】
また、可動板の重さｆは下記の（１２）式で表される。
ｆ＝ＷＬ_１×ｔρｇ …（１２）
【００２８】
ここで、ρは可動板の体積密度、ｇは重力加速度である。
【００２９】
また、可動板の撓み量ΔＸは、同じく片持ち梁の撓み量の計算方法を用いて、下記の（１３）式のようになる。
ΔＸ＝４（Ｌ_１／２）^３Ｆ／ＥＷｔ^３ …（１３）
【００３０】
ここで、Ｆは可動板の端に作用する磁気力である。そして、前記磁気力Ｆは（２）式のコイル長ｗを可動板の長さＷと見做して求める。
【００３１】
これら、トーションバーの撓み量と可動板の撓み量の計算結果を［表１］に示す。尚、可動板の撓み量は、磁気力Ｆを３０μＮとして計算したものである。
【００３２】
【表１】

【００３３】
上記の［表１］から明らかなように、幅５０μｍ、長さ１．０ｍｍのトーションバーの場合、幅６ｍｍ、長さ１３ｍｍ、厚さ５０μｍの可動板による撓み量ΔＹは、０．１７８ μｍであり、可動板の厚さを倍の１００μｍとしても、撓み量ΔＹは、０．３５６ μｍである。また、幅６ｍｍ、長さ１３ｍｍ、厚さ５０μｍの可動板の場合、磁気力による撓み量ΔＸは、０．１２５ μｍであり、可動板両端の変位量を２００μｍ程度とすれば、ガルバノミラーの特性には何ら影響はない。
【００３４】
上記のような構成からなるガルバノミラーでは、その製造に半導体の製造プロセスを利用することで比較的小型化や薄型化が図られ、コイルの発熱による影響も無視でき、可動板５の揺動特性にも優れることとなる。このため、ガルバノミラーを構成要素とするレーザ光のスキャニングシステムの小型化を図ることができ、延いては、このスキャニングシステムを利用するレーザ応用機器の小型化が図られるようになる。また、（半導体素子の製造プロセスを利用することで、）大量生産も可能となった。
【００３５】
ところが、上記のようなプロセスで製造したガルバノミラーは、例えば上記スキャニングシステムのような光学ユニットに組み込まれた状態において、落下等の衝撃に対し十分な耐久性が保証されないという欠点があり、また、光束を収束させて小スポットを形成しようとすると、このミラーの周辺に配置されるべきレンズ群を保持する光学ユニットへの取り付けが必要であり、かつ精度よく行わなければならない。特にガルバノミラーでは強い磁石を必要とするために、磁性を有するビスでは、取り付け時にドライバーからひきつけられてミラーに衝撃を与えて破損させるといった問題が発生する。また、半導体製造プロセスで形成されるミラーの支持部は、面内で発生する応力には強いが、面に垂直に働く応力にはもろくなる。したがって、ユニットの取り付け面に凹凸があると局所的な応力でビスを締め付ける時に割れる恐れがある。あるいは、締め付けにより半導体基板に生じた応力によって固有振動数が設計値からずれてしまうことがある。
【００３６】
本発明はこのような実情に鑑みなされたもので、ガルバノミラーを組み込んだ光学ユニットについて、製品として十分な強度を確保しつつ、その小型化を図ることを目的とする。
【００３７】
【課題を解決するための手段】
上記目的を達成するために、第１の発明は、
板状の枠部と、周縁部に通電により磁界を発生する平面コイルを備え、前記平面コイルで囲まれた中央部に反射鏡を備える平板状の可動板と、前記枠部に対して揺動可能に前記可動板を軸支するトーションバーと、が一体形成された半導体基板と、
前記枠部の第１面を支持し、前記可動板に対向する部分が開放されている第１支持部材と、
前記枠部の前記第１面の裏面である第２面を支持する第２支持部材と、
を有し、前記第１支持部材及び前記第２支持部材には、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の前記平面コイルに磁界を作用させ、前記可動板を挟んで対をなすよう磁石が設けられ、前記可動板を磁気力によって揺動させて光走査を行う光学ユニットであって、
前記第１支持部材及び前記第２支持部材は、前記枠部を挟んで支持した状態で、前記第１面に平行で且つ前記トーションバーの軸方向に直交する方向に関して前記可動板の両側に配置された非磁性のビスによって光学ユニット箱に固定されていることを特徴とする。
【００３８】
また第２の発明は、
板状の枠部と、周縁部に通電により磁界を発生する平面コイルを備え、前記平面コイルで囲まれた中央部に反射鏡を備える平板状の可動板と、前記枠部に対して揺動可能に前記可動板を軸支するトーションバーと、が一体形成された半導体基板と、
前記枠部の第１面を支持し、前記可動板に対向する部分が開放されている第１支持部材と、
前記枠部の前記第１面の裏面である第２面を支持する第２支持部材と、
を有し、前記第１支持部材及び前記第２支持部材には、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の前記平面コイルに磁界を作用させ、前記可動板を挟んで対をなすよう磁石が設けられ、前記可動板を磁気力によって揺動させて光走査を行う光学ユニットであって、
前記第１支持部材及び前記第２支持部材は、前記枠部を挟んで支持した状態で、前記第１支持部材及び前記第２支持部材の前記第１面に平行で且つ前記トーションバーの軸方向に直交する方向に関して前記可動板の両側の部分が光学ユニット箱に設けられたガイドレール部に嵌め込まれており、
前記ガイドレール部に嵌め込まれた前記第１支持部材及び前記第２支持部材は抑えバネにより前記ガイドレール部の内面に押し付けられて光学ユニット箱に固定されていることを特徴とする。
【００４３】
かかる構成によれば、ガルバノミラーを組み込んだ光学ユニットにとって、耐衝撃性と組み立て容易性とを両立して向上することができるようになる。
【００４４】
そしてその結果、半導体基板に形成され強力な磁石を用いるガルバノミラーが従来のものに比べて極めて小型なものとすることができるようになり、延いてはレーザ光を偏光走査するレーザスキャニングシステムの小型化を達成できるようになる。また、落下等の衝撃にもつよく所望の固有振動数を維持して組み立てることが可能となる。
【００４５】
また、とくに第４の発明によれば、ガルバノミラーと対象部剤との接合部位が接合面を形成するように接着による固定を行うことで、衝撃による応力が一箇所に集中することが避けられ、耐破損性が一層高くなる。
【００４６】
【発明の実施の形態】
以下、本発明を具体化した第１の実施の形態について、図面を参照して説明する。
【００４７】
なお、本発明の各実施の形態に適用されるガルバノミラーについて、基本的な構造及び製造プロセスは、図７〜図１４において説明した従来のガルバノミラーに関するものと略同様であるため、ここでの重複する図示・説明は割愛する。
【００４８】
以下、本発明の各実施の形態にかかるガルバノミラー、それを組み込んだ光学ユニット（光学ユニット箱）、およびその組み込みプロセス（光学ユニットの組み立てプロセス）について説明する。
【００４９】
先ず図１には、本発明の第１実施の形態にかかるガルバノミラーの製造工程を概略的に示す。
【００５０】
本実施の形態にかかるガルバノミラーの製造工程では、先ず、厚さ３００μｍのシリコン基板１０１の上下面を熱酸化して酸化膜（１μｍ）１０２を形成する（工程ａ）。次に、裏面側にホトリソグラフにより貫通穴のパターンを形成し、貫通穴部分の酸化膜をエッチング除去し（工程ｂ）、更に、可動板形成部の酸化膜を厚さ０．５μｍまで除去する（工程ｃ）。
【００５１】
次に、表面側にワックス層１０３を設けた後、貫通穴部分に異方性エッチングを１００μｍ行う（工程ｄ）。裏面側の可動板部分の薄い酸化膜を除去し（工程ｅ）、貫通穴と可動板部分に異方性エッチングを１００μｍ行う（工程ｆ）。表面側のワックス層１０３を除去し、表面側の酸化膜１０２上に、公知の電鋳コイル法によって平面コイル、電極端子部（図示せず）を形成し、また、アルミニウムの蒸着によって全反射ミラーを形成する（工程ｇ）。電鋳コイル法は、シリコン基板１０１の表面側にニッケルのスパッタを行ってニッケル層を形成し、銅電解めっきを行って銅層を形成する。次にポジ型のレジストで平面コイル及び電極端子に相当する部分をマスクし、銅エッチング、ニッケルエッチングを順次行い、エッチング後、レジストを除去し、更に、銅電解めっきを行ってニッケル層の全周を銅で覆い平面コイル及び電極端子に相当する銅層を形成する。
【００５２】
次に、銅層を除いた部分にネガ型のメッキレジストを塗布した後、銅電解めっきを行って銅層を厚くして、平面コイル及び電極端子を形成する。そして、平面コイル部分を例えば感光性ポリイミド等の絶縁層で覆う。平面コイルを２層にする場合は、再度ニッケルのスパッタ工程から絶縁層形成までの工程を繰り返し行えばよい。
【００５３】
次に、表面側にワックス層１０３′を設けた後、貫通穴及び可動板部分に異方性エッチングを１００μｍ行い、貫通穴部分を貫通させ、可動板部分を除いてワックス層１０３ ′を除去する。この際に、上下の酸化膜１０２も除去する。これにより、可動板５とトーションバー（図示せず）が形成され、図７のシリコン基板２が形成される（工程ｈ，ｉ，ｊ）。
【００５４】
次に、可動板部分のワックス層を除去した後、シリコン基板２の上下面に上側ガラス基板３と下側ガラス基板４をそれぞれ陽極接合によって結合する。次に、上下のガラス基板３，４の所定位置に永久磁石１０Ａ，１０Ｂと１１Ａ，１１Ｂを取付ける。
【００５５】
この永久磁石の取り付け方法は、図２に示すように、予め上下のプラスチックハウジング１４に磁石１０ａ、１０ｂ、１１ａ、１１ｂをそれぞれ接着しておき、これに半導体基板部１を挟み込んで固定する。
【００５６】
図２において、プラスチックハウジング１４には、穴１５ａ、１５ｂ、１６ａ、１６ｂが開けられており、互いに勘合して、ビスが通るようになっている。
【００５７】
本実施の形態では、光学ユニット箱１に対するガルバノミラー１の組み付けにあたり、図３（ａ）のごとく、非磁性のビス１７でトーションバー６の形成されていない枠部分２５ａ、２５ｂを光学ユニット箱２６の支持部１９に固定する。
図３（ｂ）は取り付け部の拡大図である。
【００５８】
同図３（ｂ）において、２２はレーザーダイオード、２３は集光用のレンズ、２４は走査光をドラム面状で集光させるレンズである。
図４において、ビス１７によってガルバノミラー１４が支持体１９に固定される。
【００５９】
ビス１７ａ、１７ｂの材料としては、非磁性の合金（非磁性のＳＵＳ）やプラスチックが用いられる。
【００６０】
このような枠部分２５ａ、２５ｂで固定する理由は、トーションバー６を軸として、ガルバノミラーの外枠と内部ミラーとは相反する方向への力が働くため、この力を安定してミラーに加えるためには、外枠部分での振動力がもっとも働く部分を固定することが好ましいからである。
【００６１】
このような非磁性のビス１７ａ、１７ｂであれば、強力なＳｍ−Ｃｏ磁石を用いても、ひきつけられてミラーを破損するといった問題を起こすことがなかった。
【００６２】
また、トーションバー６に近い枠部分で固定しようとすると、トーションバー６に応力が働いて、折れやすいことも判り本実施の形態の有効性が認められた。
【００６３】
（第２の実施の形態）
先の実施の形態では、非磁性のビス１７ａ、１７ｂを用いて光学ユニット箱体２６に固定したが、より好ましくはビス１７ａ、１７ｂとガルバノミラー１４の間に 緩衝材になる弾性体１８ａ、１８ｂ、たとえばシリコーンゴムのＯリングといったものを挿入しておくとよい。この様子を図４（ａ）にしめす。図４（ｂ）は取り付け部の拡大図である。
【００６４】
通常ビスを締めると、ビスの頭の裏の一箇所がミラーの外枠とあたり、応力の一点集中を生じる。本実施の形態によれば、ビス１７ａ、１７ｂの締め付け力が一点に集中することなく、分散されるので半導体基板内に応力が生じにくく割れが防止できる
（第３の実施の形態）
先の実施の形態では、光学ユニット箱２６の構造からすると、ガルバノミラー１４の取り付けに際してビスの締める方向が、箱の壁と干渉してやや締め難いものとなる。
【００６５】
そこで本実施の形態では、図５（ｂ）に示すごとくガルバノミラー１４の取り付けを予め光学ユニット箱２６に設けられたガイドレール２０と、抑えバネ２１とで固定するものである。図５（ａ）は光学ユニット箱の全体図である。
【００６６】
ガイドレール２０の内側の一面が光学系としての位置決め面としてはたらき、抑えバネはこの面にガルバノミラーを押し付ける方向に働く。この場合、バネの弾性で、固定されているため、光学ユニット２６に外力が働いてもその力をガイドレール２０の中でスラストして逃がすことができるか、バネ２１で吸収することができるので、光学ユニット２６に働く衝撃力に対して耐性の増す利点がある。
【００６７】
（第４の実施の形態）
本実施の形態では、光学ユニット箱２６とガルバノミラー１４との間の接着を行うことで、固定するものである。この様子を図６（ａ）と拡大図６（ｂ）に示す。この場合、用いる接着剤２７は、シリコーン系のものが好ましくかつ常温硬化型のものが便利である。多くの接着剤が熱硬化型として存在するが、熱履歴を与えると温度が下がった状態では、ガルバノミラー１４に応力を与えてしまうので、好ましくない。
【００６８】
また、アクリル系の接着剤等は揮発分でミラーが白濁してしまうので、好ましくない。
【００６９】
シリコーン系の接着剤は、硬化後も弾性を有するため、光学ユニット箱２６に外力が生じてもそれが直接ガルバノミラー１４に波及しないようにすることができる。
【００７０】
このように、上記各実施の形態にかかる光学ユニット箱（光学ユニット）の組み立て方法、及びそのような組み立て方法によって完成された光学ユニット箱（光学ユニット）によれば、シリコーン基板を用いて作成されたプレナー型ガルバノミラーを組み込んだ光学ユニットにとって、ガルバノミラーを破損させることなく確実に組み付けることができるようになり、さらに、完成品としての光学ユニットに関しても、落下等の外力による衝撃に対し十分な強度や耐久性が保証されるようになる。
【００７１】
【発明の効果】
以上説明したように、本発明によれば、ガルバノミラーを組み込んだ光学ユニットにとって、耐衝撃性と組み立て容易性とを両立して向上することができるようになる。
【００７２】
そしてその結果、半導体基板に形成され強力な磁石を用いるガルバノミラーが従来のものに比べて極めて小型なものとすることができるようになり、延いてはレーザ光を偏光走査するレーザスキャニングシステムの小型化を達成できるようになる。また、落下等の衝撃にもつよく所望の固有振動数を維持して組み立てることが可能となる。
【図面の簡単な説明】
【図１】本発明の第１の実施の形態にかかるガルバノミラーの製造工程を説明する図。
【図２】同実施の形態にかかる光学ユニットの組み立て方法を説明する図。
【図３】同実施の形態にかかる光学ユニットを説明する図。
【図４】本発明の第２の実施の形態にかかる光学ユニットを説明する図。
【図５】本発明の第３の実施の形態にかかる光学ユニットを説明する図。
【図６】本発明の第４の実施の形態にかかる光学ユニットを説明する図。
【図７】ガルバノミラーの一例を示す図。
【図８】図７のＡ−Ａ’断面図。
【図９】ガルバノミラーの動作原理を説明する図。
【図１０】ガルバノミラーの永久磁石による磁束密度分布の計算モデル図。
【図１１】磁束密度分布位置を示す図。
【図１２】磁束密度分布の計算結果を示す図。
【図１３】可動板の変位量と電流量との計算結果を示すグラフ。
【図１４】トーションバー及び可動版の撓み量の計算モデル図。
【符号の説明】
１ ガルバノミラー
１０，１１ 磁石
１４ ガルバノミラーの支持体
１７ 非磁性ビス
１８ 緩衝材
１９ 光学ユニット箱の支持部
２０ 光学ユニット箱のレール
２１ バネ
２２ レーザー
２３，２４ レンズ
２７ 接着剤[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for assembling an optical unit incorporating a galvanometer mirror, such as a laser beam scanning system, and an optical unit assembled by such a method.
[0002]
[Prior art]
Galvano mirrors are used in laser scanners that deflect and scan laser light. The principle is that when a current is passed through a moving coil placed in a magnetic field, electromagnetic force is generated in relation to the current and magnetic flux. Thus, a rotational force (torque) proportional to the current is generated. The movable coil rotates to an angle at which this torque and spring force are balanced, and the principle of the galvanometer is used to detect the presence / absence or magnitude of current by swinging the pointer through this movable coil. A reflecting mirror is provided on the integrally rotating shaft instead of the pointer.
[0003]
As a conventional practical galvanometer mirror, for example, a moving iron piece is used instead of a moving coil arranged in a magnetic field, and a magnetic path is formed by a magnetic body provided with two permanent magnets and four magnetic poles around the moving iron piece. It is configured to change the magnetic flux between the magnetic poles according to the magnitude and direction of the current passed through the drive coil wound around the magnetic body, thereby swinging the reflecting mirror through the movable iron piece and polarizing scanning the laser beam. (For example, see Kyoritsu Publishing Co., Ltd. “Practical Laser Technology”, P210-212, published on Dec. 10, 1987).
[0004]
[Problems to be solved by the invention]
By the way, along with the development of microelectronics represented by high integration of semiconductor devices, various devices have become highly functional and miniaturized, and a laser scanning system using the galvano mirror is applied, for example, a laser. The same applies to laser application equipment such as a microscope. There is a demand for further miniaturization. However, in the conventional galvanometer mirror, since the drive coil is mechanically wound, it is difficult to reduce the size further. Therefore, the laser scanning system using this galvanometer mirror and the laser application equipment using this system are further improved. Miniaturization is difficult.
[0005]
With respect to such problems, the galvanometer mirrors disclosed in JP 07-175005 A, JP 07-176255 A, JP 07-218857 A, etc. are manufactured by using a semiconductor manufacturing process. The miniaturization is aimed at.
[0006]
7 and 8 show the configuration of a conventional galvanometer mirror described in the above publication.
[0007]
7 and 8, the galvanometer mirror 1 is provided with upper and lower glass substrates 3 and 4 as upper and lower insulating substrates made of, for example, borosilicate glass on the upper and lower surfaces of a silicon substrate 2 as a semiconductor substrate. Is a three-layer structure obtained by anodic bonding. And the said upper side glass substrate 3 is laminated | stacked on the right-and-left end of FIG. 7 of the silicon substrate 2 so that the upper part of the movable plate 5 mentioned later may be open | released.
[0008]
The silicon substrate 2 includes a flat movable plate 5 and torsion bars 6 and 6 that pivotally support the movable plate 5 so as to be swingable in the vertical direction with respect to the silicon substrate 2 at the center of the movable plate 5. Are integrally formed by anisotropic etching. Therefore, the movable plate 5 and the torsion bar 6 are also made of the same material as the silicon substrate. A flat coil 7 made of a copper thin film that generates a magnetic field when energized is covered with an insulating coating on the peripheral edge of the upper surface of the movable plate 5. Here, the coil has Joule heat loss depending on the resistance, and when a thin film coil having a large resistance is mounted at a high density, the driving force is limited due to heat generation. The planar coil 7 is formed. In the electroforming coil method, a thin nickel layer is formed on a substrate by sputtering, and a copper layer is formed by performing copper electrolytic plating on the nickel layer, and a copper layer and a nickel layer are formed except for a portion corresponding to the coil. By removing it, a thin planar coil consisting of a copper layer and a nickel layer is formed. The thin film coil can be mounted with low resistance and high density, and is effective for miniaturization and thinning of micro magnetic devices. . Further, a total reflection mirror 8 as a reflection mirror is formed by aluminum vapor deposition at the center of the upper surface surrounded by the planar coil 7 of the movable plate 5. Furthermore, a pair of electrode terminals 9 and 9 are provided on the upper side surfaces of the torsion bars 6 and 6 of the silicon substrate 2 to be electrically connected via the planar coil 7 and the portions of the torsion bars 6 and 6. The electrode terminals 9 and 9 are formed simultaneously with the planar coil 7 on the silicon substrate 2 by an electroforming coil method.
[0009]
On the left and right sides of the upper and lower glass substrates 3 in the drawing, a pair of circular permanents that make a magnetic field act on the planar coil 7 portion on the opposite side of the movable plate 5 parallel to the axial direction of the torsion bars 6, 6. Magnets 10A and 10B and 11A and 11B are provided. As shown in FIG. 8, each of the three permanent magnets 10A and 10B, which are paired with each other, is provided so that the lower side is an N pole and the upper side is an S pole, and the other three permanent magnets are paired with each other. As shown in FIG. 8, the permanent magnets 11A and 11B are provided so that the lower side is the S pole and the upper side is the N pole.
[0010]
Next, the operation of the galvanometer mirror according to this example will be described. For example, as shown in FIG. 9, a current is passed through the planar coil 7 with one electrode terminal 9 as a positive pole and the other electrode terminal 9 as a negative pole. As indicated by the arrows in FIG. 8, on both sides of the movable plate 5, permanent magnets 10A and 10B, 11A and 11B, that is, in a direction crossing the planar coil 7 along the plane of the movable plate 5 between the upper and lower magnets. When a magnetic field is formed and a current flows through the planar coil 7 in the magnetic field, the current / magnetic flux density / current is applied to the planar coil 7 according to the current density and magnetic flux density of the planar coil 7, in other words, to both ends of the movable plate 5. A magnetic force F acts in a direction according to the left hand rule of force framing (shown in FIG. 9), and this force is obtained from the Lorentz force.
[0011]
This magnetic force F is obtained by the following equation (1), where i is the current density flowing through the planar coil 7 and B is the magnetic flux density of the permanent magnets 10A, 10B and 11A, 11B.
F = i × B (1)
Actually, it depends on the number n of turns of the planar coil 7 and the coil length w (shown in FIG. 9) on which the magnetic force F acts, and the following equation (2) is obtained.
F = nw (i × B) (2)
On the other hand, when the movable plate 5 rotates, the torsion bars 6 and 6 are twisted, and the relationship between the spring reaction force F ′ of the torsion bars 6 and 6 generated thereby and the displacement angle φ of the movable plate 5 is as follows. Equation (3) is obtained.
φ = (Mx / GIp)
= (F ′ × L / 8.5 × 10⁹Xr⁴) × l1 (3)
Here, Mx is a torsional moment, G is a transverse elastic modulus, and Ip is a second moment of polar section. L, l1, and r are the distance from the central axis of the torsion bar to the power point, the length of the torsion bar, and the radius of the torsion bar, respectively, and are shown in FIG.
[0012]
Then, the movable plate 5 rotates to a position where the magnetic force F and the spring reaction force F ′ are balanced. Therefore, it can be seen that the displacement angle φ of the movable plate 5 is proportional to the current i flowing through the planar coil 7 by substituting F in the equation (2) for F ′ in the equation (3). Therefore, the displacement angle φ of the movable plate 5 can be controlled by controlling the current flowing through the planar coil 7. For example, the total reflection mirror 8 is in a plane perpendicular to the axes of the torsion bars 6 and 6. The reflection direction of the laser beam incident on the beam can be freely controlled, and the laser beam can be scanned if the displacement angle of the total reflection mirror 8 is continuously repeated.
[0013]
Next, the calculation result of the magnetic flux density distribution by the permanent magnet will be described.
[0014]
FIG. 10 shows a magnetic flux density distribution calculation model of the cylindrical permanent magnet used in this example, and the surface of each of the N pole and S pole of the permanent magnet is divided into a minute region dy, and the magnetic flux at the required point is calculated. . Assuming that the magnetic flux density formed on the N pole surface is Bn and the magnetic flux density formed on the S pole surface is Bs, these are calculated from the calculation formulas of the magnetic flux density distribution by the cylindrical permanent magnets: (4), (5) It can be calculated by the formula
[0015]
[Expression 1]

[0016]
[Expression 2]

[0017]
  Here, the magnetic flux density B at an arbitrary point is obtained by synthesizing Bn and Bs, and is expressed by equation (6).
  B = Bn + Bs (6)
In the above equations (5) and (6), Br is the residual magnetic flux density x, y, z of the permanent magnet is a coordinate representing an arbitrary point in the space around the permanent magnet, and l is the N pole surface of the permanent magnet and S The distance from the pole face, d is the radius of each pole face. For example, using a Sm-Co permanent magnet DIANET DM-18 (trade name, manufactured by Seiko Electronic Components) having a radius of 1 mm, a height of 1 mm, and a residual magnetic flux density of 0.85 T,12FIG. 12 shows the result of calculating the magnetic flux density distribution in the plane a perpendicular to the surface of the permanent magnet arranged as shown in FIG.
[0018]
When arranged as shown in FIG. 11, the space between the magnets has a magnetic flux density of approximately 0.3 T or more. Next, the calculation result of the displacement amount of the movable plate 5 will be described. The width of the planar coil 7 formed on the movable plate 5 is 100 μm, the number of turns is 14, the thickness of the movable plate 5 is 20 μm, the radius of the torsion bar 6 is 25 μm, the length is 1 mm, and the width of the movable plate 5 is 4 mm. The thickness was determined from the formulas (2) and (3) with 5 mm. In addition, 0.3T obtained by the above-mentioned magnetic flux density distribution calculation is used for magnetic flux density.
[0019]
As a result, as shown in FIGS. 13A and 13B, it can be seen that a displacement angle of 2 degrees can be obtained at a current of 1.5 mA. FIG. 13C shows the relationship between the current and the amount of heat Q generated. The amount of heat generated per unit area at this time is 13 μW / cm.²It became. Next, the relationship between the amount of heat generation and heat dissipation will be described. The amount of heat generated is Joule heat generated by the resistance of the coil. Therefore, the amount of heat Q generated per unit time is expressed by the following equation (7).
Q = i2 × R (7)
[0020]
Here, i is the current flowing through the coil, and R is the resistance of the coil. The heat release amount Qc due to the heat generation amount convection is expressed by the following equation (8).
Qc = hSΔT (8)
[0021]
Where h is the heat transfer coefficient (air is 5 × 10^-3~ 5x10^-2[Watt / cm²° C]), S is the surface area of the element, and ΔT is the temperature difference between the element surface and air.
[0022]
The area of the movable plate that becomes the heat generating part is 20 mm.²Assuming (4 × 5), equation (8) is
Qc = 1.0 × ΔT [m Watts / ° C.] (8) ′
Tens of microwatts / cm²It can be seen that the problem of the temperature rise of the element can be ignored if the heat generation amount is about a level. For reference, the heat dissipation amount Qr due to radiation is expressed by the following equation (9).
Qr = εSσT⁴  ... (9)
[0023]
Where ε is the emissivity (ε = 1D for black bodies, generally ε <1), S is the surface area of the element, σ is the Stefan-Boltzmann constant (π2k⁴/ 60h³c²), T is the surface temperature of the element. Further, the heat release amount Qa due to conduction from the torsion bar is expressed by the following equation (10).
Qa = 2λ (S / l₁) ΔT (10)
[0024]
Where λ is the thermal conductivity (silicon is 84 watts / mK), S is the cross-sectional area of the torsion bar, l₁  Is the length of the torsion bar, and ΔT is the temperature difference between both ends of the torsion bar. If the radius of the torsion bar is 25 μm and the length is 1 mm, the equation (10) is
Qa = 0.1 × ΔT [m Watts / ° C.] (10) ′
It becomes.
[0025]
  Next, the bending of the torsion bar due to its own weight and the bending of the movable plate due to electromagnetic force will be described. Figure14Shows these calculation models. If the length of the torsion bar is l1, the width of the torsion bar is b, the weight of the movable plate is f, the thickness of the movable plate is t, the width of the movable plate is W, and the length of the movable plate is L1, the torsion bar The deflection amount ΔY of the above is expressed by the following equation (11) using a method of calculating the deflection amount of the cantilever.
  ΔY = (1/2) (4l₁ ³f / Ebt³(11)
[0026]
Here, E is the Young's modulus of silicon.
[0027]
Further, the weight f of the movable plate is expressed by the following equation (12).
f = WL₁× tρg (12)
[0028]
Here, ρ is the volume density of the movable plate, and g is the gravitational acceleration.
[0029]
Further, the bending amount ΔX of the movable plate is expressed by the following equation (13) using the same method for calculating the bending amount of the cantilever.
ΔX = 4 (L₁/ 2)³F / EWt³  ... (13)
[0030]
Here, F is a magnetic force acting on the end of the movable plate. The magnetic force F is obtained by considering the coil length w of the equation (2) as the length W of the movable plate.
[0031]
The calculation results of the deflection amount of the torsion bar and the deflection amount of the movable plate are shown in [Table 1]. The amount of bending of the movable plate is calculated by setting the magnetic force F to 30 μN.
[0032]
[Table 1]

[0033]
As is clear from the above [Table 1], in the case of a torsion bar having a width of 50 μm and a length of 1.0 mm, the deflection amount ΔY by the movable plate having a width of 6 mm, a length of 13 mm and a thickness of 50 μm is 0.178 μm. Yes, even if the thickness of the movable plate is doubled to 100 μm, the deflection amount ΔY is 0.356 μm. Further, in the case of a movable plate having a width of 6 mm, a length of 13 mm, and a thickness of 50 μm, the amount of deflection ΔX due to magnetic force is 0.125 μm, and if the displacement amount at both ends of the movable plate is about 200 μm, the characteristics of the galvanometer mirror Has no effect.
[0034]
The galvanometer mirror having the above-described configuration can be made relatively small and thin by using a semiconductor manufacturing process for its manufacture, the influence of heat generation of the coil can be ignored, and the swing characteristics of the movable plate 5 can be ignored. It will be even better. For this reason, it is possible to reduce the size of the laser beam scanning system including the galvanometer mirror as a constituent element, and further, it is possible to reduce the size of laser application equipment that uses this scanning system. In addition, mass production has become possible (by utilizing the manufacturing process of semiconductor elements).
[0035]
However, the galvanometer mirror manufactured by the process as described above has a disadvantage that sufficient durability against an impact such as a drop is not guaranteed in a state where the galvanometer mirror is incorporated in an optical unit such as the above scanning system. In order to form a small spot by converging the light beam, it is necessary to attach it to an optical unit that holds a lens group to be arranged around the mirror and to perform it with high accuracy. In particular, since a galvano mirror requires a strong magnet, a magnetic screw causes a problem that the mirror is attracted by a driver at the time of mounting and is damaged by impacting the mirror. Further, the mirror support formed in the semiconductor manufacturing process is strong against stress generated in the plane, but is fragile to stress acting perpendicular to the plane. Therefore, if the mounting surface of the unit is uneven, it may crack when the screw is tightened by local stress. Alternatively, the natural frequency may deviate from the design value due to the stress generated in the semiconductor substrate by tightening.
[0036]
The present invention has been made in view of such circumstances, and an object of the present invention is to reduce the size of an optical unit incorporating a galvanomirror while ensuring sufficient strength as a product.
[0037]
[Means for Solving the Problems]
  In order to achieve the above object, the first invention provides:
  Plate-likeA frame,A peripheral coil is provided with a planar coil that generates a magnetic field when energized, and the central part surrounded by the planar coilA flat movable plate provided with a reflecting mirror;,in frontCan swing with respect to the frameThe movable plateA semiconductor substrate integrally formed with a torsion bar that supports the shaftWhen,
  A first support member that supports the first surface of the frame portion and is open to a portion facing the movable plate;
  A second support member that supports a second surface that is the back surface of the first surface of the frame portion;
HaveMagnets are applied to the first support member and the second support member so that a magnetic field is applied to the planar coil on the opposite side of the movable plate parallel to the axial direction of the torsion bar, and the movable plate is sandwiched between the magnets. Provided,By swinging the movable plate by magnetic forcelightAn optical unit for scanning,
  The first support member and the second support member are:The frameThePinchSupportIn the stateNon-magnetic elements disposed on both sides of the movable plate in a direction parallel to the first surface and perpendicular to the axial direction of the torsion bar.By screwWhatOptical unitIn the boxIt is fixed.
[0038]
  Also, the second invention is
  Plate-likeA frame,A peripheral coil is provided with a planar coil that generates a magnetic field when energized, and the central part surrounded by the planar coilA flat movable plate provided with a reflecting mirror;,in frontCan swing with respect to the frameThe movable plateA semiconductor substrate integrally formed with a torsion bar that supports the shaftWhen,
  A first support member that supports the first surface of the frame portion and is open to a portion facing the movable plate;
  A second support member that supports a second surface that is the back surface of the first surface of the frame portion;
HaveMagnets are applied to the first support member and the second support member so that a magnetic field is applied to the planar coil on the opposite side of the movable plate parallel to the axial direction of the torsion bar, and the movable plate is sandwiched between the magnets. Provided,By swinging the movable plate by magnetic forcelightAn optical unit for scanning,
  The first support member and the second support member are:The frameThePinchSupportIn the stateGuide rail portions provided on both sides of the movable plate in the optical unit box with respect to a direction parallel to the first surface of the first support member and the second support member and perpendicular to the axial direction of the torsion bar. Fitted,
  The first support member and the second support member fitted in the guide rail portion are pressed against the inner surface of the guide rail portion by a holding spring.Optical unitIn the boxIt is fixed.
[0043]
According to this configuration, for an optical unit incorporating a galvanometer mirror, both impact resistance and ease of assembly can be improved.
[0044]
As a result, the galvanometer mirror formed on the semiconductor substrate and using a powerful magnet can be made extremely small compared to the conventional one, and the laser scanning system for scanning the polarization of the laser beam can be reduced. Can be achieved. Further, it is possible to assemble while maintaining a desired natural frequency well with respect to impact such as dropping.
[0045]
In particular, according to the fourth aspect of the present invention, the stress due to the impact can be prevented from being concentrated in one place by performing the fixing by bonding so that the bonding portion between the galvanometer mirror and the target member forms a bonding surface. Further, the damage resistance is further increased.
[0046]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
[0047]
Note that the basic structure and manufacturing process of the galvanometer mirror applied to each embodiment of the present invention is substantially the same as that related to the conventional galvanometer mirror described in FIGS. Duplicate illustrations and explanations are omitted.
[0048]
Hereinafter, a galvanometer mirror according to each embodiment of the present invention, an optical unit (optical unit box) in which the galvanomirror is incorporated, and an incorporation process (an assembly process of the optical unit) will be described.
[0049]
First, FIG. 1 schematically shows a manufacturing process of a galvanometer mirror according to a first embodiment of the present invention.
[0050]
In the manufacturing process of the galvanomirror according to the present embodiment, first, the upper and lower surfaces of the 300 μm thick silicon substrate 101 are thermally oxidized to form oxide films (1 μm) 102 (step a). Next, a through hole pattern is formed on the back side by photolithography, the oxide film in the through hole portion is removed by etching (step b), and the oxide film in the movable plate forming portion is further removed to a thickness of 0.5 μm. (Step c).
[0051]
Next, after the wax layer 103 is provided on the surface side, anisotropic etching is performed on the through hole portion by 100 μm (step d). The thin oxide film on the movable plate portion on the back side is removed (step e), and anisotropic etching is performed on the through hole and the movable plate portion by 100 μm (step f). The wax layer 103 on the surface side is removed, a planar coil and electrode terminal portions (not shown) are formed on the oxide film 102 on the surface side by a known electroforming coil method, and a total reflection mirror is formed by vapor deposition of aluminum. Is formed (step g). In the electroforming coil method, nickel is sputtered on the surface side of the silicon substrate 101 to form a nickel layer, and copper electrolytic plating is performed to form a copper layer. Next, mask the portions corresponding to the planar coil and electrode terminals with a positive resist, perform copper etching and nickel etching in sequence, remove the resist after etching, and further perform copper electrolytic plating to make the entire circumference of the nickel layer. Is covered with copper, and a copper layer corresponding to the planar coil and electrode terminal is formed.
[0052]
Next, after applying a negative plating resist to the portion excluding the copper layer, copper electrolytic plating is performed to thicken the copper layer to form a planar coil and electrode terminals. Then, the planar coil portion is covered with an insulating layer such as photosensitive polyimide. When two planar coils are used, the steps from the nickel sputtering step to the insulating layer formation may be repeated.
[0053]
  Next, after providing the wax layer 103 ′ on the surface side, anisotropic etching is performed on the through hole and the movable plate portion to 100 μm to penetrate the through hole portion, and the wax layer 103 ′ is removed except for the movable plate portion. . At this time, the upper and lower oxide films 102 are also removed. Thereby, the movable plate 5 and the torsion bar (not shown) are formed, and the silicon substrate 2 of FIG. 7 is formed (steps h, i)., J).
[0054]
  Next, after removing the wax layer of the movable plate portion, the upper glass substrate 3 and the lower glass substrate 4 are bonded to the upper and lower surfaces of the silicon substrate 2 by anodic bonding, respectively.TheNext, permanent magnets 10A, 10B and 11A, 11B are attached to predetermined positions of the upper and lower glass substrates 3, 4.The
[0055]
As shown in FIG. 2, the permanent magnets are attached by attaching magnets 10a, 10b, 11a, and 11b to upper and lower plastic housings 14 in advance, and sandwiching and fixing the semiconductor substrate 1 therebetween.
[0056]
In FIG. 2, holes 15a, 15b, 16a, 16b are formed in the plastic housing 14 so that the screws pass through each other by fitting.
[0057]
In the present embodiment, when the galvanometer mirror 1 is assembled to the optical unit box 1, the frame portions 25a and 25b in which the torsion bar 6 is not formed with the nonmagnetic screws 17 as shown in FIG. It fixes to the support part 19 of this.
FIG. 3B is an enlarged view of the attachment portion.
[0058]
In FIG. 3B, 22 is a laser diode, 23 is a condensing lens, and 24 is a lens that condenses the scanning light in the form of a drum surface.
In FIG. 4, the galvanometer mirror 14 is fixed to the support 19 by screws 17.
[0059]
As a material of the screws 17a and 17b, a nonmagnetic alloy (nonmagnetic SUS) or a plastic is used.
[0060]
The reason why the frame portions 25a and 25b are fixed is that a force in a direction opposite to the outer frame of the galvano mirror and the inner mirror acts on the torsion bar 6 as an axis, and this force is stably applied to the mirror. For this purpose, it is preferable to fix the portion where the vibration force works most in the outer frame portion.
[0061]
With such non-magnetic screws 17a and 17b, even if a strong Sm-Co magnet is used, there is no problem that the mirror is damaged by being attracted.
[0062]
Further, it was found that if the frame portion near the torsion bar 6 was fixed, stress was applied to the torsion bar 6 and it was easily broken, and the effectiveness of the present embodiment was confirmed.
[0063]
(Second Embodiment)
In the previous embodiment, the non-magnetic screws 17a and 17b are used to fix the optical unit box 26. More preferably, the elastic members 18a and 18b serving as cushioning materials are provided between the screws 17a and 17b and the galvanometer mirror 14. For example, a silicone rubber O-ring may be inserted. This state is shown in FIG. FIG. 4B is an enlarged view of the attachment portion.
[0064]
Normally, when a screw is tightened, one point on the back of the head of the screw hits the outer frame of the mirror, and a single stress is concentrated. According to the present embodiment, the tightening force of the screws 17a and 17b is dispersed without concentrating on one point, so that stress is hardly generated in the semiconductor substrate and cracking can be prevented.
(Third embodiment)
In the previous embodiment, according to the structure of the optical unit box 26, the direction in which the screw is tightened when the galvano mirror 14 is attached interferes with the wall of the box and is somewhat difficult to tighten.
[0065]
Therefore, in the present embodiment, as shown in FIG. 5B, the galvanometer mirror 14 is fixed by the guide rail 20 provided in advance in the optical unit box 26 and the restraining spring 21. FIG. 5A is an overall view of the optical unit box.
[0066]
One surface inside the guide rail 20 serves as a positioning surface as an optical system, and the restraining spring acts in a direction in which the galvanometer mirror is pressed against this surface. In this case, since it is fixed by the elasticity of the spring, even if an external force is applied to the optical unit 26, the force can be thrust away in the guide rail 20 or can be absorbed by the spring 21. There is an advantage that resistance to the impact force acting on the optical unit 26 is increased.
[0067]
(Fourth embodiment)
In the present embodiment, the optical unit box 26 and the galvano mirror 14 are bonded together to be fixed. This state is shown in FIG. 6A and an enlarged view 6B. In this case, the adhesive 27 used is preferably a silicone-based adhesive and is conveniently a room-temperature curable adhesive. Many adhesives exist as a thermosetting type, but when a thermal history is applied, stress is applied to the galvanomirror 14 when the temperature is lowered, which is not preferable.
[0068]
In addition, acrylic adhesives and the like are not preferable because the mirror becomes cloudy due to volatile components.
[0069]
Since the silicone-based adhesive remains elastic after curing, even if an external force is generated in the optical unit box 26, it can be prevented from directly affecting the galvanometer mirror 14.
[0070]
As described above, according to the method for assembling the optical unit box (optical unit) according to each of the above embodiments, and the optical unit box (optical unit) completed by such an assembling method, the optical unit box is manufactured using a silicone substrate. The optical unit incorporating the planar galvanometer mirror can be securely assembled without damaging the galvanometer mirror, and the optical unit as a finished product is also adequate for impact due to external forces such as dropping. Strength and durability are guaranteed.
[0071]
【The invention's effect】
As described above, according to the present invention, for an optical unit incorporating a galvanometer mirror, both impact resistance and ease of assembly can be improved.
[0072]
As a result, the galvanometer mirror formed on the semiconductor substrate and using a powerful magnet can be made extremely small compared to the conventional one, and the laser scanning system for scanning the polarization of the laser beam can be reduced. Can be achieved. Further, it is possible to assemble while maintaining a desired natural frequency well with respect to impact such as dropping.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining a manufacturing process of a galvanomirror according to a first embodiment of the present invention.
FIG. 2 is a view for explaining an assembly method of the optical unit according to the embodiment;
FIG. 3 is a diagram for explaining an optical unit according to the embodiment;
FIG. 4 is a diagram illustrating an optical unit according to a second embodiment of the present invention.
FIG. 5 is a diagram illustrating an optical unit according to a third embodiment of the present invention.
FIG. 6 is a diagram for explaining an optical unit according to a fourth embodiment of the present invention.
FIG. 7 is a diagram showing an example of a galvanometer mirror.
8 is a cross-sectional view taken along the line A-A ′ of FIG. 7;
FIG. 9 is a diagram for explaining the operating principle of a galvanometer mirror.
FIG. 10 is a calculation model diagram of magnetic flux density distribution by a permanent magnet of a galvano mirror.
FIG. 11 is a view showing a magnetic flux density distribution position.
FIG. 12 is a diagram showing a calculation result of a magnetic flux density distribution.
FIG. 13 is a graph showing a calculation result of the displacement amount and current amount of the movable plate.
FIG. 14 is a calculation model diagram of a deflection amount of a torsion bar and a movable plate.
[Explanation of symbols]
1 Galvano mirror
10,11 magnet
14 Galvano mirror support
17 Non-magnetic screws
18 cushioning material
19 Supporting part of optical unit box
20 Optical unit box rail
21 Spring
22 Laser
23, 24 lens
27 Adhesive

Claims (4)

A plate-shaped frame portion includes a planar coil for generating a magnetic field by energizing the periphery, and a flat plate-shaped movable plate having a reflecting mirror in the center surrounded by the planar coil, rocking to the front Symbol frame portion a torsion bar for axially supporting the rotatably to said movable plate, and the semiconductor substrate but are integrally formed,
A first support member that supports the first surface of the frame portion and is open to a portion facing the movable plate;
A second support member that supports a second surface that is the back surface of the first surface of the frame portion;
The first support member and the second support member have a magnetic field acting on the planar coil on the opposite side of the movable plate parallel to the axial direction of the torsion bar, and a pair is sandwiched between the movable plates. magnet is provided so as to form, the movable plate an optical unit for optical scanning is swung by the magnetic force,
The first support member and the second support member, said frame portion while supporting Nde clamping on both sides of the movable plate with respect to a direction orthogonal and in the axial direction of the torsion bar is parallel to the first surface an optical unit which is characterized in that it is fixed to the optical unit box I by the bis arranged nonmagnetic. Before Symbol wherein the first support member second support member, the optical unit according to claim 1, characterized in that it is fixed to the optical unit box by the non-magnetic screws via an elastic body cushioning material. The optical unit according to claim 1 wherein the first support member and said second support member, characterized that you have been formed of plastic. A plate-shaped frame portion includes a planar coil for generating a magnetic field by energizing the periphery, and a flat plate-shaped movable plate having a reflecting mirror in the center surrounded by the planar coil, rocking to the front Symbol frame portion a torsion bar for axially supporting the rotatably to said movable plate, and the semiconductor substrate but are integrally formed,
A first support member that supports the first surface of the frame portion and is open to a portion facing the movable plate;
A second support member that supports a second surface that is the back surface of the first surface of the frame portion;
The first support member and the second support member have a magnetic field acting on the planar coil on the opposite side of the movable plate parallel to the axial direction of the torsion bar, and a pair is sandwiched between the movable plates. Eggplant
Yo magnets are provided, an optical unit for optical scanning by swinging the movable plate by a magnetic force,
The first support member and the second support member, said frame portion while supporting Nde clamping, the first support member and the said and the torsion bar axis parallel to the first surface of the second support member The parts on both sides of the movable plate with respect to the direction orthogonal to the direction are fitted into guide rail portions provided in the optical unit box ,
An optical unit which is characterized in that it is fixed to the guide rail section the optical unit box is pressed against the inner surface of the front Symbol guide rails said fitted to portion the first support member and the second support member is suppressed spring.

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