JP3694914B2 - Objective lens driving apparatus and recording / reproducing apparatus using the same - Google Patents

Description

【００２２】
かかる対物レンズ駆動装置１００において、小型化を図るためには、弾性部材１０１の弾性変位部分の長さ寸法Ｌを短くしたり、厚み寸法ｔを小さくすることが考慮される。しかしながら、上記数式（１）より明らかなように、弾性部材１０１の基本特性を決定する一次共振周波数（ｆ_０）は、弾性部材１０１の弾性変位部分の長さ寸法Ｌに関して、フォーカシング方向及びトラッキング方向のいずれにおいてもｆ_０＝αＬ^３／２の関係にある。但し、αは、比例定数とする。
【００２３】
一次共振周波数（ｆ_０）は、例えば、弾性部材１０１の長さ寸法Ｌを、１０ｍｍから１２ｍｍに変更した場合には、約３／４に減少する。したがって、一次共振周波数が４０Ｈｚの仕様の対物レンズ駆動装置１００は、他の仕様を同一として弾性部材１０１の弾性変位部分の長さ寸法Ｌを２ｍｍ長くすることにより、一次共振周波数が３０Ｈｚの対物レンズ駆動装置に置換される。
【００２４】
換言すれば、対物レンズ駆動装置１００においては、小型化を図るために弾性部材１０１の長さ寸法Ｌを小さくした場合には、この弾性部材１０１の一次共振周波数（ｆ_０）が大きくなってしまうといった問題点がある。例えば、弾性部材１０１の一次共振周波数（ｆ_０）は、４０Ｈｚ以上となった場合には制御動作を困難な状態とする。
【００２５】
一方、弾性部材１０１の厚み寸法ｔを小ならしめて対物レンズ駆動装置１００の小型化を図る対策は、薄厚の弾性材料板に高精度の加工を施こさなければならないことから、取り扱いが極めて難しく製造コストを大幅に増加させるといった問題点がある。
【００２６】
したがって、本発明は、対物レンズをフォーカシング方向とトラッキング方向とに弾性変位自在に支持する弾性部材の弾性変形部の実質的な有効長を確保することによって一次共振周波数値の低減を図り、以って装置の小型化或いは感度特性の向上を達成した対物レンズ駆動装置及びこれを用いた記録再生装置を提供することを目的に提案されたものである。
【００２７】
【課題を解決するための手段】
この目的を達成した本発明に係る対物レンズ駆動装置及びこれを用いた記録再生装置は、対物レンズと、一端側には対物レンズが組み付けられるホルダ部が形成されるとともに、他端側には対物レンズの光軸と平行な方向に作用する磁気駆動力を発生するフォーカシングコイルと、対物レンズの光軸と直交する方向に作用する磁気駆動力を発生するトラッキングコイルとが組み付けられたボビン部材と、このボビン部材の両側面部にそれぞれ光軸と平行な方向に離間して配置され、一端部が固定されるとともに他端部が固定部であるボビン支持部材に固定されることによってボビン部材をフォーカシング方向とトラッキング方向とに弾性変位自在に支持する複数個の弾性部材と、マグネットが接合されるとともにフォーカシングコイルの内部に介挿される第１のヨークと、トラッキングコイルと対向するようにして位置された第２のヨークとが立ち上がり形成されることによって磁気回路部を構成しかつボビン支持部材を固定支持するベース部材とを備え、上記複数個の弾性部材は、それぞれ板バネ材によって形成され、上記ボビン支持部材に取り付けられる基端部と、上記ボビン部材に取り付けられる嵌合部と、上記基端部と直交する方向に形成された連結片を介して互いに連結された第１の折返し片と第２の折返し片とによって形成される折返し部と、上記嵌合部と上記第２の折返し片との間に上記第２の折返し片に連続して形成される弾性変形部とを有し、上記折返し部には、上記弾性部材の共振現象を抑制する粘弾性を有するダンプ剤が添着されている。
【００２８】
また、本発明に係る対物レンズ駆動装置及びこれを用いた記録再生装置において、上記第１の折返し片及び上記第２の折返し片は、それぞれ上記基端部に平行する方向に形成され、上記第１の折返し片と上記基端部とは、上記基端部と直交する方向に形成された第２の連結片を介して連結されて第２の折返し部を形成するように構成してもよい。
【００２９】
さらに、本発明に係る対物レンズ駆動装置及びこれを用いた記録再生装置は、対物レンズと、一端側には対物レンズが組み付けられるホルダ部が形成されるとともに、他端側には対物レンズの光軸と平行な方向に作用する磁気駆動力を発生するフォーカシングコイルと、対物レンズの光軸と直交する方向に作用する磁気駆動力を発生するトラッキングコイルとが組み付けられたボビン部材と、このボビン部材の両側面部にそれぞれ光軸と平行な方向に離間して配置され、一端部が固定されるとともに他端部が固定部であるボビン支持部材に固定されることによってボビン部材をフォーカシング方向とトラッキング方向とに弾性変位自在に支持する複数個の弾性部材と、マグネットが接合されるとともにフォーカシングコイルの内部に介挿される第１のヨークと、トラッキングコイルと対向するようにして位置された第２のヨークとが立ち上がり形成されることによって磁気回路部を構成しかつボビン支持部材を固定支持するベース部材とを備え、上記複数個の弾性部材は、それぞれ板バネ材によって形成され、上記ボビン支持部材に取り付けられる基端部と、上記ボビン部材に取り付けられる嵌合部と、上記基端部と直交する方向に形成された連結片を介して互いに連結された第１の折返し片と第２の折返し片とによって形成される折返し部と、上記嵌合部と上記第２の折返し片との間に上記第２の折返し片に連続して形成される弾性変形部とを有し、上記第１の折返し片及び上記第２の折返し片を包囲して上記弾性部材の共振を抑制する粘弾性を有するダンプ剤が添着されている。
【００３０】
【作用】
以上のように構成された本発明に係る対物レンズ駆動装置及びこれを用いた記録再生装置によれば、寸法仕様が同一である場合にも、折返し部が形成された弾性部材は、弾性変位部分の実質的な有効長さが確保される。したがって、対物レンズ駆動装置は、一次共振周波数（ｆ_０）を抑制しかつ感度特性を向上しながら小型化が図られる。
【００３１】
また、本発明によれば、共振動作を抑制するダンプ剤を最適位置に限定的に組み付けることが可能とされ、さらに折返し部の形状仕様を適宜選択することによって、弾性部材の共振時及び動作時の弾性変形の状態を調整することが可能とされ、この弾性部材の特性の最適化が図られる。
【００３２】
【実施例】
以下、本発明の具体的な実施例を図面を参照して詳細に説明する。本発明に係る対物レンズ駆動装置１は、後述する弾性部材２０に特徴を有し、基本的な構成を上述した従来の対物レンズ駆動装置１００とほぼ同様とした板バネ形構造の直交２軸アクチュエータ機構を備えた対物レンズ駆動装置である。したがって、以下の説明においては、上述した従来の対物レンズ駆動装置１００と同一部材には同一番号を付す。なお、対物レンズ駆動装置１は、後述するように４本の弾性部材２０Ａ乃至弾性部材２０Ｄを備えているが、これらを共通して説明する場合には単に弾性部材２０と表現する。
【００３３】
すなわち、対物レンズ駆動装置１は、図１乃至図３に示すように、対物レンズ２と、この対物レンズ２が組み付けられた対物レンズホルダ３と、この対物レンズホルダ３及び磁気回路部４を構成する後述する各部材が組み合わされたボビン部材５と、このボビン部材５を支持するところの後述する４本の弾性部材２０（２０Ａ乃至２０Ｄ）と、これら弾性部材２０の基端部を支持するボビン支持部材６及び磁性材料によって形成されたベース部材７とを主たる構成部材として構成されている。
【００３４】
ボビン部材５は、合成樹脂材料によって成形され、上述した対物レンズホルダ３が組み付けられるホルダ部８と、磁気回路部４の構成各部材が組み合わされる磁気回路部品組付け部９とから構成されている。ホルダ部８は、対物レンズ２を組み合わせた対物レンズホルダ３が嵌合される対物レンズ取付け穴１０が設けられた全体が薄厚の筒状部として構成されている。また、このホルダ部８には、対物レンズ取付け穴１０に嵌合された対物レンズ３の外周面を保持する複数の保持片１７Ａ乃至保持片１７Ｃが一体に形成されている。
【００３５】
ボビン部材５の磁気回路部品組付け部９は、略々凸字状の大きな開口部として構成され、対物レンズ２を光軸と平行な方向に駆動変位させる磁気駆動力を発生させるフォーカシングコイル１２と、対物レンズ２を光軸と直交する方向に駆動変位させる磁気駆動力を発生させる一対のトラッキングコイル１３Ａ、１３Ｂが組み付けられる。フォーカシングコイル１２は、対物レンズ取付け穴１０と反対側のやや幅広の開口部側に位置して磁気回路部品組付け部９に組み付けられる。
【００３６】
磁気回路部品組付け部９に対応するボビン部材５の両側面部には、後述する弾性部材２０Ａ乃至弾性部材２０Ｄのそれぞれの嵌合部２３Ａ乃至嵌合部２３Ｄが差し込まれる水平方向の嵌合スリット５ａ乃至嵌合スリット５ｄがそれぞれ上下方向に離間して設けられている。したがって、ボビン部材５は、これら弾性部材２０Ａ乃至弾性部材２０Ｄによって、上下方向及び左右方向に弾性変位自在に支持されることになる。
【００３７】
フォーカシングコイル１２は、磁気回路部品組付け部９を構成するコイル組付け開口部１１の開口寸法とほぼ同径の角筒状を呈しており、このコイル組付け開口部１１に嵌着されて組み付けられる。また、フォーカシングコイル１２は、コイル組付け開口部１１に組み付けられた後、外周面と開口部内壁との間に接着剤が充填されることによって、ボビン部材５にしっかりと固定される。また、フォーカシングコイル１２は、コイル組付け開口部１１に組み付けられた状態において、コイルの巻き方向が対物レンズ２の光軸と直交する方向であるように構成されている。
【００３８】
トラッキングコイル１３Ａ、１３Ｂは、それぞれ薄幅の矩形枠状を呈して構成されており、フォーカシングコイル１２の一方側面部と対物レンズとの間に位置するようにして、互いに一方側面部を重ね合わせるようにして磁気回路部品組付け部９を構成するコイル組付け開口部１１に嵌着されて組み付けられる。これらトラッキングコイル１３Ａ、１３Ｂは、フォーカシングコイル１２の一方側面部に接着剤によってしっかりと固定される。また、これらトラッキングコイル１３Ａ、１３Ｂは、磁気回路部品組付け部９に組み付けられた状態において、少なくとも相対向する辺に対物レンズ２の光軸と平行な直線部分を有するように構成されている。
【００３９】
ベース部材７は、詳細な形状の図示を省略するが、珪素鋼等の高透磁率材料によって略々Ｈ字状に形成され、中央連結片の相対向する側縁部から第１のヨーク片１４Ａと第２のヨーク片１４Ｂとがそれぞれ互いに平行に対峙するようにして一体に立ち上がり形成されている。
【００４０】
第１のヨーク片１４Ａは、磁気回路部品組付け部９に組み付けられたフォーカシングコイル１２の中心孔を貫通している。また、第２のヨーク片１４Ｂは、トラッキングコイル１３Ａ、１３Ｂと対向して磁気回路部品組付け部９に貫通している。第１のヨーク片１４Ａには、第２のヨーク片１４Ｂとの対向側面に、やや厚みのある板状のマグネット１５が接着剤等を用いてしっかりと取付け固定されている。第１のヨーク片１４Ａと第２のヨーク片１４Ｂとの先端部には、図１において鎖線で示すように、磁性材で形成したヨーク板１６が組み合わされる。
【００４１】
したがって、磁気回路部４は、上述したベース部材７と、このベース部材７に一体に立ち上がり形成された第１のヨーク片１４Ａ及び第２のヨーク片１４Ｂと、第１のヨーク片１４Ａに取り付けられたマグネット１５及びヨーク板１６とから構成される。そして、フォーカシングコイル１２及びトラッキングコイル１３Ａ、１３Ｂは、この磁気回路部４の磁界中を横切るように位置して磁気回路部品組付け部９に組み付けられている。また、これらフォーカシングコイル１２及びトラッキングコイル１３Ａ、１３Ｂへの電流の供給は、後述するように、弾性部材２０Ａ乃至弾性部材２０Ｄを利用して行われている。
【００４２】
ボビン支持部材６は、第１のヨーク片１４Ａ及び第２のヨーク片１４Ｂの反対側に位置して、中央開口部分を跨ぐようにしてベース部材７に組み付けられている。すなわち、ボビン支持部材６は、底面部に図示しない半導体レーザから出射された光束の光路を構成する逆Ｕ字状の凹部６ａが形成されるとともに、両側面部にはボビン部材５を支持する弾性部材２０Ａ乃至弾性部材２０Ｄの基端部２１Ａ乃至基端部２１Ｄがそれぞれ差し込まれる水平方向の嵌合スリット６ｂ乃至嵌合スリット６ｅがそれぞれ上下方向に離間して設けられている。
【００４３】
弾性部材２０Ａ乃至弾性部材２０Ｄは、薄いバネ板材料を打ち抜き形成した部材であって、ボビン支持部材６の左側面部に組み付けられる弾性部材２０Ａ、２０Ｂと、右側面部に組み付けられる弾性部材２０Ｃ、２０Ｄとは互いに左右対象形とされるとともに、同一側面部に組み付けられる弾性部材２０Ａ、２０Ｂ及び弾性部材２０Ｃ、２０Ｄとは互いに同一形状とされている。
【００４４】
図４を参照してこれら弾性部材２０の構成を説明すれば、弾性部材２０は、ボビン支持部材６の両側面部に設けた嵌合スリット６ｂ乃至嵌合スリット６ｄにそれぞれ差し込まれる略矩形状の基端部２１と、幅狭の弾性変形部２２と、ボビン部材５の両側面部に設けた嵌合スリット５ａ乃至嵌合スリット５ｄにそれぞれ差し込まれる略矩形状の嵌合部２３とから構成されている。弾性部材２０の基端部２１の近傍には、互いに組み合わされた状態でＬ字状の開口部３０と矩形状の開口部３１とを打ち抜くことによって、全体が略Ｕ字状を呈する折返し部２９が形成されている。
【００４５】
すなわち、折返し部２９は、基端部２１と直交する方向の連結片２７を介して互いに連結された基端部２１と平行する方向の第１の折返し片２６及び第２の折返し片２８とから構成されている。外側に位置する第２の折返し片２８は、そのまま弾性変形部２２と連続している。なお、基端部２１の他端部３３は、折返し部２９を囲むように切り残されてリード線接続部として構成されている。
【００４６】
また、弾性部材２０は、嵌合部２３の一端側に、弾性変形部２２と平行なコイル接続片２４が一体に形成されている。このコイル接続片２４には、ボビン部材５の上下面に形成された半球状の位置決めダボ３２に対応して位置決め孔２５が設けられている。
【００４７】
弾性部材２０Ａ乃至弾性部材２０Ｄは、基端部２１Ａ乃至基端部２１Ｄがボビン支持部材６の両側面部に設けた嵌合スリット６ｂ乃至嵌合スリット６ｄにそれぞれ差し込まれて固定されることにより、ボビン支持部材６にそれぞれ片持ち状態で支持される。そして、弾性部材２０Ａ乃至弾性部材２０Ｄは、自由端側の嵌合部２３Ａ乃至嵌合部２３Ｄがボビン部材５の両側面部に設けた嵌合スリット５ａ乃至嵌合スリット５ｄにそれぞれ差し込まれて固定されることにより、このボビン部材５を上下方向及び左右方向に弾性支持する。
【００４８】
また、弾性部材２０Ａ乃至弾性部材２０Ｄは、ボビン部材５をボビン支持部材６に弾性支持するように、これら両部材間に組み合わせられた状態において、コイル接続片２４の位置決め孔２５がボビン部材５の位置決めダボ３２にそれぞれ相対係合される。コイル接続片２４には、フォーカシングコイル１２及びトラッキングコイル１３Ａ、１３Ｂのコイル線がそれぞれ接続される。また、基端部２１のリード線接続部３３には、フォーカシングコイル１２及びトラッキングコイル１３Ａ、１３Ｂに駆動電流を供給する駆動源とを接続するリード線が接続される。したがって、弾性部材２０は、フォーカシングコイル１２及びトラッキングコイル１３Ａ、１３Ｂへの電流供給線としても機能する。
【００４９】
以上のように構成された対物レンズ駆動装置１を備えた光ピックアップ装置は、半導体レーザから出射された光束を対物レンズ２を介して光ディスクの情報記録面に照射するとともに、この情報記録面からの反射光を対物レンズ２を介してビームスプリッタによって分光し、フォーカシング方向とトラッキング方向との差異をディテクターによって検出する。検出されたフォーカシング方向とトラッキング方向の位置ずれは、フォーカスエラー信号或いはトラッキングエラー信号としてサーボ回路で処理され、それらに応じた駆動電流がフォーカシングコイル１２及びトラッキングコイル１３Ａ、１３Ｂへ供給される。
【００５０】
対物レンズ駆動装置１は、フォーカシングコイル１２にフォーカスエラー信号に応じた駆動電流が供給されると、このフォーカシングコイル１２に流れる電流と、磁気回路部４を構成するマグネット１５からの磁束とによって、ボビン部材５をフォーカシング方向へと駆動する磁気駆動力を発生させる。この磁気駆動力は、弾性部材２０Ａ乃至弾性部材２０Ｄを上下方向に弾性変位させ、ボビン部材５、換言すれば対物レンズ２を光軸と平行なフォーカシング方向へと調動させて、光ディスクに照射する半導体レーザのフォーカシングの調整を行わせる。
【００５１】
対物レンズ駆動装置１は、第１のトラッキングコイル１３Ａ又は第２のトラッキングコイル１３Ｂに、トラッキングエラー信号に応じた駆動電流が供給されると、これらトラッキングコイル１３Ａ、１３Ｂに流れる電流と、磁気回路部４を構成するマグネット１５からの磁束とによって、ボビン部材５をトラッキング方向へと駆動する磁気駆動力を発生させる。この磁気駆動力は、弾性部材２０Ａ乃至弾性部材２０Ｄを左右方向へと弾性変位させ、ボビン部材５、換言すれば対物レンズ２を光軸と直交するトラッキング方向へと調動させて、光ディスクに照射する半導体レーザのトラッキングの調整を行わせる。
【００５２】
上述したように、弾性部材２０は、基本特性であるフォーカシング方向の一次共振周波数（ｆ_０）が数式１で表される。弾性部材２０は、折返し部２９を形成したことにより、弾性変形部分の長さ寸法が（Ｌ１＋Ｌ２）となり、従来の弾性部材と比較して実質的に大ならしめられて構成される。勿論、この長さ寸法（Ｌ１＋Ｌ２）は、上述した一次共振周波数（ｆ_０）を算出する数式１のＬにそのまま置換して適用されるものではない。したがって、対物レンズ駆動装置１において、弾性変形有効長さＬ０は、有限要素法（ＦＥＭ）を用いて以下の条件で算出される。
【００５３】
すなわち、弾性部材２０は、図４における各部の寸法が、以下の仕様によって形成されているものとする。
【００５４】
厚み寸法：ｔ＝０．０７ｍｍ（但し、全体が均一とする）
第２の折返し片２８を含む弾性変形部２２の全長：Ｌ１＝９．８ｍｍ
第１の折返し片２６の長さ寸法：Ｌ２＝２．０ｍｍ弾性変形部２２の幅寸法ｂ１及び第２の折返し片２８の幅寸法ｂ３：ｂ１＝ｂ３＝０．０９ｍｍ
第１の折返し片２６の幅寸法：ｂ２＝０．１５ｍｍ
可動部の質量：Ｍ＝０．２４ｇ
ヤング率Ｅ＝１．１２×１０^−１１Ｎ／ｍ ^２ （荷重／断面積）
以上の条件より、フォーカシング方向の一次共振周波数（ｆ_０）は、約３５Ｈｚ、またトラッキング方向の一次共振周波数（ｆ_０）は、４７Ｈｚとなる。
【００５５】
ここで、第１の折返し片２６の幅寸法ｂ２＝０．１５ｍｍを、弾性変形部２２の幅寸法ｂ１と同一と見做し、数式１から弾性変形有効長さＬ０を算出すると、フォーカシング方向については、１０．６ｍｍ、またトラッキング方向については、１０．３ｍｍの値が得られる。
【００５６】
したがって、対物レンズ駆動装置１は、折返し部２９を有する弾性部材２０を備えることによって、折返し部２９を有しない弾性部材と比較すると、弾性変形有効長さ寸法Ｌ０が、フォーカシング方向については、１０．６ｍｍ−９．８ｍｍ＝０．８ｍｍで、約８％増加され、またトラッキング方向については、１０．３ｍｍ−９．８ｍｍ＝０．５ｍｍで、約５％増加されることになる。また、一次共振周波数（ｆ_０）については、５Ｈｚ程度、約１２％の低減が図られる。
【００５７】
このように、対物レンズ駆動装置１によれば、弾性部材２０に折返し部２９を形成することにより、この弾性部材２０の実際の長さ寸法が同一仕様のままで、一次共振周波数（ｆ_０）の低減を図ることができる。
【００５８】
図５は、弾性部材の他の例を示し、この弾性部材４０は、上述した弾性部材２０と基本的な構成をほぼ同一に形成されるが、折返し部４９を構成する外側の第２の折返し片４８の一部にクランク状の連結部５３が形成された点に特徴を有する。すなわち、弾性部材４０は、ボビン支持部材６の両側面部に設けた嵌合スリット６ｂ乃至嵌合スリット６ｄにそれぞれ差し込まれる略矩形状の基端部４１と、幅狭とされた弾性変形部４２と、ボビン部材５にの両側面部に設けた嵌合スリット５ａ乃至嵌合スリット５ｄにそれぞれ差し込まれる略矩形状の嵌合部４３とから構成されている。基端部４１には、互いに組み合わされた状態でＬ字状の開口部５０と略クランク状の開口部５１とを打ち抜くことによって、全体が略Ｕ字状を呈する折返し部４９が形成されている。
【００５９】
折返し部４９は、基端部４１と直交する方向の連結片４７を介して互いに連結され、基端部４１と平行する方向の内側に位置する第１の折返し片４６及び外側に位置する第２の折返し片４８とから構成されている。第２の折返し片４８は、開口部５１によって形成されたクランク状の連結部５３を介して弾性変形部４２に連設されている。なお、基端部４１の他端部５２は、折返し部４９を囲むようにして切り残されることにより、リード線接続部として構成されている。
【００６０】
なお、弾性部材４０には、嵌合部４３の一端側に、弾性変形部４２と平行なコイル接続片４４が一体に形成され、このコイル接続片４４には、ボビン部材５の上下面に形成された半球状の位置決めダボ３２に対応して位置決め孔４５が設けられている。
【００６１】
以上のように対物レンズ駆動装置を構成する弾性部材４０は、基端部４１がボビン支持部材６の両側面部に設けた嵌合スリット６ｂ乃至嵌合スリット６ｄにそれぞれ差し込まれて固定されることにより、ボビン支持部材６にそれぞれ片持ち状態で支持される。また、弾性部材４０は、自由端側の嵌合部４３がボビン部材５の両側面部に設けた嵌合スリット５ａ乃至嵌合スリット５ｄにそれぞれ差し込まれて固定されることにより、このボビン部材５を上下方向及び左右方向に弾性支持する。
【００６２】
さらに、弾性部材４０は、ボビン部材５をボビン支持部材６に弾性支持するように、これら両部材間に組み合わせられた状態において、コイル接続片４４の位置決め孔４５がボビン部材５の位置決めダボ３２にそれぞれ相対係合される。そして、このコイル接続片４４には、フォーカシングコイル１２及びトラッキングコイル１３Ａ、１３Ｂのコイル線がそれぞれ接続される。また、基端部４１のリード線接続部５２には、フォーカシングコイル１２及びトラッキングコイル１３Ａ、１３Ｂに駆動電流を供給する駆動源とを接続するリード線が接続される。したがって、弾性部材４０は、フォーカシングコイル１２及びトラッキングコイル１３Ａ、１３Ｂへの電流供給線としても機能する。
【００６３】
以上のように、折返し部４９に略クランク状の連結部５３を形成した弾性部材４０は、弾性変形部の実質的な長さ寸法が大ならしめられるとともに、フォーカシング方向或いはトラッキング方向に弾性変位されたときに発生する共振現象を抑制し、或いは振動の迅速な減衰を図るダンピング作用の効率化を図ることができる。
【００６４】
図６は、弾性部材の他の実施例を示し、この弾性部材６０は、上述した弾性部材２０と基本的な構成をほぼ同一に形成されるが、図２５における寸法Ｌの範囲の一部或いは図４における寸法Ｌ２の部分に代えて形成される折返し部６６を有する点に特徴を有している。すなわち、弾性部材６０は、弾性変形部６１の一部に切欠き６５を設けて基端部側弾性変形部６１Ａと嵌合部側弾性変形部６１Ｂとに分割して形成し、これら基端部側弾性変形部６１Ａと嵌合部側弾性変形部６１Ｂとを略凸字状の折返し部６６によって連続した構成する。
【００６５】
折返し部６６は、基端側部分が、基端部側弾性変形部６１Ａの先端から直交する方向に連設された第１の基端部側連結片６２Ａと、この基端部側連結片６２Ａの先端から基端部側弾性変形部６１Ａと平行して基端部側に戻る方向に連設された第１の基端部側折返し片６３Ａと、この第１の基端部側折返し片６３Ａの先端からさらに直交する方向に連設された第２の基端部側連結片６４Ａとから構成されている。
【００６６】
また、折返し部６６は、嵌合部側が、嵌合部側弾性変形部６１Ｂの先端から直交する方向に連設された第１の嵌合部側連結片６２Ｂと、この嵌合部側連結片６２Ｂの先端から嵌合部側弾性変形部６１Ｂと平行して嵌合部側に戻る方向に連設された第１の嵌合部側折返し片６３Ｂと、この第１の嵌合部側折返し片６３Ｂの先端からさらに直交する方向に連設された第２の嵌合部側連結片６４Ｂとから構成されている。
【００６７】
そして、折返し部６６は、第２の基端部側連結片６４Ａと第２の嵌合部側連結片６４Ｂとの間に弾性変形部６１と平行な第２の折返し片６５Ａが連設されることによって、上述したように、全体として略凸字状に構成される。なお、折返し部６６は、基端部或いは嵌合部等のその他の構成を上述した弾性部材２０とほぼ同一とするため、その説明を省略する。このように、弾性部材６０は、上述した構成の折返し部６６を形成したことにより、弾性変形部が、第１の基端部側折返し片６３Ａと第１の嵌合部側折返し片６３Ｂ及び第２の折返し片６５Ａを加えた長さ寸法で得られ、さらに大ならしめられて構成される。
【００６８】
図７乃至図９は、クランク状の折曲部７３が形成され基端部７２の幅寸法を弾性変形部７２の幅寸法に対して大ならしめて形成した弾性部材７０について、ＦＥＭ解析を行った場合のＺ軸（フォーカシング方向）回りのローリングの共振現象を模式的に示した図である。また、図１０乃至図１２は、Ｕ字状の折返し部７６を有しかつ全体がほぼ同一の幅寸法に形成された弾性部材７５について、ＦＥＭ解析を行った場合のＺ軸（フォーカシング方向）回りのローリングの共振現象を模式的に示した図である。なお、これらの図において、Ｘ軸は、弾性部材７０の弾性変形部７２の長手方向を示し、Ｙ軸はトラッキング方向を示している。
【００６９】
図７乃至図９から明らかなように、弾性部材７０は、Ｚ軸回りのローリング現象に対して基端部７１が大きく変形するとともに弾性変形部７２もこの基端部７１近傍において大きく変形する。したがって、図７乃至図９に示した弾性部材７０については、共振現象の抑制対策として、変形状態が大きい弾性変形部７２の全体に亘ってダンプ剤を添着することが有効であると判断される。換言すれば、弾性部材７０は、弾性変形部７２の全体に亘ってダンプ剤が添着されるため、例えばこの弾性部材７０の質量特性も大きく変化してしまう。
【００７０】
一方、弾性部材７５については、図１０乃至図１２から明らかなように、Ｚ軸回りのローリング現象に対して折返し部７６の近傍における変形状態が著しく大きくなっている。したがって、折返し部７６を有する弾性部材７５については、共振現象の抑制対策として、図１３に示すように、変形状態が大きい折返し部７６にダンプ剤８０を添着することが有効であると判断される。そして、折返し部７６にダンプ剤８０が添着された弾性部材７５は、図１４及び図１５に示すように、弾性部材７５と平行に添着部６Ａ乃至６Ｄがそれぞれ凹設されたボビン支持部材６に取り付けられる。
【００７１】
また、上述した弾性部材６０については、図１６（Ａ）に示すように、折返し部６６に、基端部側弾性変形部６１Ａと嵌合部側弾性変形部６１Ｂとに跨って、各片を包囲するようにしてダンプ剤８０が添着される。また、この弾性部材６０の折返し部６６には、図１６（Ｂ）に示すように、第１の基端部側折返し片６３Ａ及び第１の嵌合部側折返し片６３Ｂ、第２の基端部側連結片６４Ａ及び第２の嵌合部側連結片６４Ｂ、第２の折返し片６５Ａとに跨ってダンプ剤８０を添着する構成としてもよい。
【００７２】
以上のように、折返し部を形成した弾性部材においては、共振現象を抑制するダンプ剤を限定した箇所、すなわち折返し部を構成する互いに平行な各片を包囲するようにしてダンプ剤を限定的に添着すればよい。したがって、この弾性部材は、ダンプ剤の添着が容易に行われ、またその添着によって特性が大きく変化するといったことは無い。
【００７３】
一方、対物レンズ駆動装置１において、一次共振周波数（ｆ_０）値における共振現象の発生度合Ｑは、この対物レンズ駆動装置１の基本特性を決定する重要なパラメータの１つである。共振現象の発生度合Ｑは、図１７に示すように、一次共振周波数（ｆ_０）値付近の急激なゲインの増大によるものであり、対物レンズ駆動装置１においてはより小さい値が好ましい。そして、この共振現象の発生度合Ｑは、共振現象が発生している弾性部材の変形状態が著しい箇所にダンプ剤を添着することによって低減することが可能である。
【００７４】
図１８乃至図２０は、上述した折返し部２９を有する弾性部材２０について、ＦＥＭ解析を行った場合のフォーカシング方向の一次共振周波数（ｆ_０）値における共振時の変形状態を模式的に示した図である。また、図２１乃至図２３は、折返し部２９を有する弾性部材２０について、ＦＥＭ解析を行った場合のトラッキング方向の一次共振周波数（ｆ_０）値における共振時の変形状態を模式的に示した図である。
【００７５】
これらの図から明らかなように、基端部２１の近傍に折返し部２９が形成された弾性部材２０は、弾性変形部２２のＸ軸方向の変形状態が両端部において大きく異にしている。すなわち、弾性部材２０は、ボビン部材５との連結部である嵌合部２３側においては、変形がほとんど生じないが、ボビン支持部材６との連結部である基端部２１において大きな変形が発生する。したがって、この弾性部材２０には、共振現象を抑制するダンプ剤を添着する箇所として、折返し部２９が適当であることが明らかである。
【００７６】
基端部の近傍に折返し部を有しない従来の弾性部材１０１においては、図２０における領域Ａで示す基端部近傍の変形現象が極めて小さい。このため、弾性部材１０１は、共振現象を抑制するダンプ剤の添着箇所の発見が極めて困難である。換言すれば、弾性部材２０は、基端部２１の近傍に折返し部２９を形成することによって、一次共振周波数（ｆ_０）値付近のダンプを容易に実現し、共振現象の発生度合Ｑの低減を図ることができる。
【００７７】
ここで、弾性部材に添着されるダンプ剤としては、一般にブチル、ゴム等の減衰特性の大きい粘弾性を有する合成樹脂材料等が用いられるが、例えば、紫外線硬化型の合成樹脂を用いた場合には、紫外線の照射量を制御することによって所望の粘弾性率を得ることができ、極めて効果的である。
【００７８】
なお、本発明は、上述した各弾性部材に限定されるものではなく、さらに種々展開されるものである。すなわち、基端部の近傍に形成される折返し部は、弾性変形部の長手方向であるＸ軸と、トラッキング方向であるＹ軸によって構成される面、換言すればベース部材と平行な面内において、Ｘ軸方向に対して少なくとも１箇所に略Ｕ字状に連続して折り返された部位として構成されればよく、折返し片の長さ寸法、幅寸法或いは折返し部の数等については、ダンピングの付与方法等、対物レンズ駆動装置の設計条件に応じて設定される。また、ベース部材と直交する方向を幅寸法とした弾性部材については、トラッキング方向であるＹ軸とフォーカシング方向であるＺ軸によって構成される面内で、上述した折返し部が形成されることは勿論である。
【００７９】
【発明の効果】
本発明に係る対物レンズ駆動装置及びこれを用いた記録再生装置によれば、複数個の弾性部材が、それぞれ板バネ材によって形成されかつ少なくとも１箇所にベース部材と平行な面内において略Ｕ字状に折り返された部位が連続して構成される折返し部が形成されたことによって、一次共振周波数値の低減が図られ、装置の小型化或いは周波数特性の向上が達成される。
【００８０】
また、本発明に係る対物レンズ駆動装置及びこれを用いた記録再生装置によれば、複数個の弾性部材が、それぞれ板バネ材によって形成されかつ少なくとも１箇所にベース部材と平行な面内において略Ｕ字状に折り返された部位が連続して構成される折返し部が形成されるとともに、折り返し部を構成する互いに平行な各片を包囲して弾性部材の共振を抑制するダンプ剤が添着されたことによって、一次共振周波数値の低減が図られ、装置の小型化或いは周波数特性の向上が達成されるとともに、共振現象の発生度合を低減させることができる。
【図面の簡単な説明】
【図１】本発明に係る対物レンズ駆動装置を示す全体斜視図である。
【図２】同対物レンズ駆動装置の全体平面図である。
【図３】同対物レンズ駆動装置の全体側面図である。
【図４】同対物レンズ駆動装置に備えられ、対物レンズをフォーカシング方向及びトラッキング方向に変位自在に支持する２軸アクチュエータを構成する弾性部材を一部省略して示した斜視図である。
【図５】弾性部材の例を一部省略して示した斜視図である。
【図６】弾性部材の例を要部のみを示した斜視図である。
【図７】基端部が幅太に形成された弾性部材について、ＦＥＭ解析を行った場合の、共振時の弾性変形状態を３次元方向から模式的に示した図である。
【図８】同弾性部材について、ＦＥＭ解析を行った場合の、弾性変形部の長手方向であるＸ軸方向と、トラッキング方向であるＹ軸方向との共振時の弾性変形状態を模式的に示した図である。
【図９】同弾性部材について、ＦＥＭ解析を行った場合の、弾性変形部の長手方向であるＸ軸方向と、フォーカシング方向であるＺ軸方向との共振時の弾性変形状態を模式的に示した図である。
【図１０】基端部の近傍に折返し部が形成された弾性部材について、ＦＥＭ解析を行った場合の、共振時の弾性変形状態を３次元方向から模式的に示した図である。
【図１１】同弾性部材について、ＦＥＭ解析を行った場合の、弾性変形部の長手方向であるＸ軸方向と、トラッキング方向であるＹ軸方向との共振時の弾性変形状態を模式的に示した図である。
【図１２】同弾性部材について、ＦＥＭ解析を行った場合の、弾性変形部の長手方向であるＸ軸方向と、フォーカシング方向であるＺ軸方向との共振時の弾性変形状態を模式的に示した図である。
【図１３】弾性部材に添着されるダンプ剤の位置を説明するために示す要部平面図である。
【図１４】弾性部材に添着されるダンプ剤の位置を説明するために示す要部側面図である。
【図１５】弾性部材に添着されるダンプ剤の位置を説明するために示す正面図である。
【図１６】弾性部材に添着されるダンプ剤の位置を説明するために示す要部斜視図である。
【図１７】弾性部材のフォーカシング方向の周波数特性を模式的に示した図であり、一次共振周波数（ｆ_０）付近における共振度合Ｑの特性図である。
【図１８】基端部の近傍に折返し部が形成された弾性部材について、ＦＥＭ解析を行った場合の、フォーカシング方向の一次共振周波数（ｆ_０）値における弾性変形状態を３次元方向から模式的に示した図である。
【図１９】同弾性部材について、ＦＥＭ解析を行った場合の、弾性変形部の長手方向であるＸ軸方向と、トラッキング方向であるＹ軸方向との共振時の弾性変形状態を模式的に示した図である。
【図２０】同弾性部材について、ＦＥＭ解析を行った場合の、弾性変形部の長手方向であるＸ軸方向と、フォーカシング方向であるＺ軸方向との共振時の弾性変形状態を模式的に示した図である。
【図２１】基端部の近傍に折返し部が形成された弾性部材について、ＦＥＭ解析を行った場合の、トラッキング方向の一次共振周波数（ｆ_０）値における弾性変形状態を３次元方向から模式的に示した図である。
【図２２】同弾性部材について、ＦＥＭ解析を行った場合の、弾性変形部の長手方向であるＸ軸方向と、トラッキング方向であるＹ軸方向との共振時の弾性変形状態を模式的に示した図である。
【図２３】同弾性部材について、ＦＥＭ解析を行った場合の、弾性変形部の長手方向であるＸ軸方向と、フォーカシング方向であるＺ軸方向との共振時の弾性変形状態を模式的に示した図である。
【図２４】従来の対物レンズ駆動装置を示す全体斜視図である。
【図２５】従来の対物レンズ駆動装置に備えられる弾性部材の斜視図である。
【符号の説明】
１ 対物レンズ駆動装置、 ２ 対物レンズ、 ５ ボビン部材、 ６ ボビン支持部材、 ７ ベース部材、 ８ ホルダ部、 ９ 磁気回路部品組付け部、１１ コイル組付け開口部、 １２ フォーカシングコイル、 １３ トラッキングコイル、 １４ ヨーク、 １５ マグネット、 ２０ 弾性部材、 ２１ 基端部、 ２２ 弾性変形部、 ２３ 嵌合部、 ２６ 第１の折返し片、２８ 第２の折返し片、 ２９ 折返し部、 ８０ ダンプ剤[0001]
[Industrial application fields]
The present invention relates to an objective lens driving device and a recording / reproducing device using the same.
[0002]
[Prior art]
2. Description of the Related Art An optical disc recording / reproducing apparatus that uses a disc-shaped optical recording medium (hereinafter referred to as an optical disc) such as an optical disc or a magneto-optical disc as a recording medium reproduces an information signal recorded on the optical disc or records an information signal. The optical pickup device is provided. This optical pickup device includes a semiconductor laser as a light source that emits a light beam applied to an information signal recording surface of an optical disc, an optical system block including optical components such as a beam splitter that separates return light from the optical disc, and a semiconductor laser. And an objective lens driving device for converging the light beam emitted from the information signal recording surface of the optical disc by the objective lens and causing the light beam to follow the recording track.
[0003]
The objective lens driving device includes a direction in which the objective lens is perpendicular to the information signal recording surface of the optical disc, that is, a focusing direction parallel to the optical axis of the objective lens, and an inner and outer peripheral direction of the information signal recording surface of the optical disc, that is, the optical axis of the objective lens. Is a device that adjusts in a tracking direction orthogonal to. In this objective lens driving device, for example, the objective lens is adjusted in a range of 2 mm in the focusing direction and 0.8 mm in the tracking direction, so that the orthogonal 2 using the magnetic driving force generated by the control current supplied to the coil arranged in the magnetic field is used. A shaft actuator mechanism is provided.
[0004]
In addition, the orthogonal two-axis actuator mechanism that has been put into practical use includes a spring support structure that provides smooth drive characteristics without friction, and shaft rotation that is easy to obtain assembly accuracy and excellent in maintaining the tilt posture of the objective lens. A sliding structure method is provided. In addition, the orthogonal biaxial actuator mechanism of the spring support structure type is divided into a moving coil type and a moving magnet type, and the orthogonal biaxial actuator mechanism of the axial rotation sliding structure type is divided into an inner optical path type and an outer optical path type. It is done.
[0005]
On the other hand, in an orthogonal biaxial actuator mechanism of a spring support structure type, a hinge-type structure, a wire-type structure, or a leaf spring-type structure is known as the structure of the elastic member that holds the objective lens. An orthogonal two-axis actuator mechanism having a leaf spring type structure is extremely effective for downsizing the objective lens driving device from the viewpoint of workability or operation characteristics.
[0006]
As shown in FIG. 24, a conventional objective lens driving device 100 having such a leaf spring structure orthogonal biaxial actuator mechanism includes an objective lens 2, an objective lens holder 3 to which the objective lens 2 is assembled, A bobbin member 5 in which members described later constituting the objective lens holder 3 and the magnetic circuit unit 4 are combined, four elastic members 101 (101A to 101D) supporting the bobbin member 5, and the elastic members 101 A bobbin support member 6 that supports the base end portion and a base member 7 formed of a magnetic material are configured as main components.
[0007]
The bobbin member 5 includes a holder portion 8 to which the above-described objective lens holder 3 is assembled and a magnetic circuit component assembly portion 9 to which the constituent members of the magnetic circuit portion 4 are combined. The holder portion 8 is provided with an objective lens mounting hole 10 into which the objective lens holder 3 is fitted. The holder portion 8 is integrally formed with a plurality of holding pieces 17A to 17C that hold the outer surface of the objective lens holder 3 fitted in the objective lens mounting hole 10.
[0008]
The magnetic circuit component assembly portion 9 of the bobbin member 5 includes a focusing coil 12 that generates a magnetic driving force that drives and displaces the objective lens 2 in a direction parallel to the optical axis, and the objective lens 2 in a direction orthogonal to the optical axis. A pair of tracking coils 13A and 13B and a pair of yoke pieces 14A and 14B that generate a magnetic driving force for driving displacement are assembled. The focusing coil 12 is configured such that the winding direction of the coil is parallel to the optical axis of the objective lens 2 in a state where the focusing coil 12 is assembled to the magnetic circuit component assembly unit 9. The tracking coils 13 </ b> A and 13 </ b> B are configured to have linear portions parallel to the optical axis of the objective lens 2 at least on opposite sides when assembled in the magnetic circuit component assembly 9.
[0009]
The base member 7 is integrally formed so that the first yoke piece 14A and the second yoke piece 14B face each other in parallel. The first yoke piece 14 </ b> A passes through the center hole of the focusing coil 12 assembled in the magnetic circuit component assembly part 9. Further, the second yoke piece 14B passes through the magnetic circuit component assembling portion 9 so as to face the tracking coils 13A and 13B. A plate-like magnet 15 having a slight thickness is attached to the first yoke piece 14A on the side surface facing the second yoke piece 14B. A yoke plate 16 is combined with the tip portions of the first yoke piece 14A and the second yoke piece 14B as shown by a chain line in FIG.
[0010]
Therefore, the magnetic circuit unit 4 includes the above-described base member 7, the first and second yoke pieces 14A and 14B that are integrally formed on the base member 7, and the magnet attached to the first yoke piece 14A. 15 and a yoke plate 16. The focusing coil 12 and the tracking coils 13A and 13B are respectively arranged so as to cross the magnetic field of the magnetic circuit unit 4. The current is supplied to the focusing coil 12 and the tracking coils 13A and 13B using the elastic members 101A to 101D, respectively.
[0011]
The bobbin support member 6 is assembled and fixed on the base member 7 on the opposite side of the first yoke piece 14A and the second yoke piece 14B. That is, the bobbin support member 6 is formed with an inverted U-shaped recess 6a constituting an optical path of a light beam emitted from a semiconductor laser (not shown) on the bottom surface portion, and elastic members 101A to 101D on both side surface portions. The horizontal fitting slits 6b to 6e into which the base end portions are respectively inserted are provided apart from each other in the vertical direction.
[0012]
The elastic members 101A to 101D are members formed by punching a thin spring plate material, and have the same shape on the left and right sides. As shown in FIG. 25, the elastic member 101 has a narrow elastic deformation portion 101b integrally projecting from one side edge of a rectangular base end portion 101a, and a bobbin member 5 and a distal end portion of the elastic deformation portion 101b. The fitting part 101c is formed. The fitting portion 101c is integrally formed with a coil connection portion 101e provided with a positioning hole 101d that engages with an alignment dowel formed in the bobbin member 5.
[0013]
Although not shown, a dumping agent is attached to each elastic member 101. The dumping agent is made of, for example, an ultraviolet curable resin material, and has an effect of suppressing a resonance operation that occurs when the elastic member 101 is elastically displaced, or for quickly damping vibration.
[0014]
In the objective lens driving apparatus 100 configured as described above, when a driving current corresponding to a focus error signal is supplied to the focusing coil 12, the current flowing in the focusing coil 12 and the magnets that constitute the magnetic circuit unit 4 are provided. The magnetic drive force for driving the bobbin member 5 in the focusing direction is generated by the magnetic flux from 15. This magnetic driving force adjusts the focusing of the semiconductor laser that irradiates the optical disk by adjusting the objective lens 2 in a focusing direction parallel to the optical axis.
[0015]
The elastic member 101 whose base end portion 101a is supported by the bobbin support member 6 causes the bobbin member 5, that is, the objective lens 2 to be moved when the elastic deformation portion 101b is elastically displaced in the vertical direction in FIG. It moves up and down.
[0016]
When the driving current corresponding to the tracking error signal is supplied to the first tracking coil 13A or the second tracking coil 13B, the objective lens driving device 100 emits light from the objective lens 2 of the tracking coil 13A or the tracking coil 13B. A magnetic driving force for driving the bobbin member 5 in the tracking direction is generated by the current flowing through the portion parallel to the axis and the magnetic flux from the magnet 15 constituting the magnetic circuit unit 4. This magnetic driving force causes the objective lens 2 to adjust in the tracking direction orthogonal to the optical axis, thereby adjusting the tracking of the semiconductor laser irradiated onto the optical disk.
[0017]
The elastic member 101 having the base end portion 101a supported by the bobbin support member 6 causes the bobbin member 5, that is, the objective lens 2 to move when the elastic deformation portion 101b is elastically displaced in the horizontal direction in FIG. It moves left and right.
[0018]
[Problems to be solved by the invention]
In the objective lens driving device 100 described above, the objective lens 2, the objective lens holder 3, the bobbin member 5, the focusing coil 12, and the tracking coil 13 constitute a movable part as a whole, and serve as the elastic members 101A to 101D. Supported and tuned in the focusing or tracking direction. By the way, since the elastic members 101A to 101D are members in which one end is fixed to the bobbin member 5 and the other end is fixed to the bobbin support member 6, they can be regarded as both-end fixed beams.
[0019]
Further, in the objective lens driving device, the displacement operation of the movable part constituted by each member described above is substantially constant in the low frequency band with respect to the input current, but the frequency is high in the high band exceeding a certain frequency value. As it rises, a vibration operation with a small amplitude occurs at an inclination of −40 db / dec. This certain frequency value, that is, the primary resonance frequency (f₀) Determines the basic characteristics of the elastic member 101 and changes depending on the shape and material.
[0020]
Therefore, in the objective lens driving device 100, the movable part constituted by each member described above is regarded as a concentrated mass M, and the length dimension of the elastic displacement portion of the elastic member 101 is L, as shown in FIG. When the width dimension is b, the thickness dimension is t, and the Young's modulus is E, the primary resonance frequency (f₀) Can be expressed by the following formula (1). The primary resonance frequency (f₀) Is expressed by exchanging the width dimension b and the thickness dimension t.
[0021]
[Expression 1]

[0022]
In the objective lens driving device 100, in order to reduce the size, it is considered to shorten the length dimension L of the elastic displacement portion of the elastic member 101 or to reduce the thickness dimension t. However, as is clear from the above formula (1), the primary resonance frequency (f₀) For the length L of the elastic displacement portion of the elastic member 101, f in both the focusing direction and the tracking direction.₀= ΑL^3/2Are in a relationship. However, α is a proportionality constant.
[0023]
Primary resonance frequency (f₀) Is reduced to about 3/4 when the length L of the elastic member 101 is changed from 10 mm to 12 mm. Therefore, the objective lens driving apparatus 100 having a specification with a primary resonance frequency of 40 Hz has the same specification as the other specification, and the length L of the elastic displacement portion of the elastic member 101 is increased by 2 mm, whereby the objective lens with a primary resonance frequency of 30 Hz is obtained. It is replaced with a drive unit.
[0024]
In other words, in the objective lens driving device 100, when the length L of the elastic member 101 is reduced in order to reduce the size, the primary resonance frequency (f₀) Will become large. For example, the primary resonance frequency (f₀) Makes the control operation difficult when 40 Hz or higher.
[0025]
On the other hand, a measure for reducing the thickness t of the elastic member 101 and reducing the size of the objective lens driving device 100 is that it is extremely difficult to handle because the thin elastic material plate must be processed with high precision. There is a problem that the cost is greatly increased.
[0026]
Therefore, the present invention aims to reduce the primary resonance frequency value by ensuring a substantial effective length of the elastically deforming portion of the elastic member that supports the objective lens so as to be elastically displaceable in the focusing direction and the tracking direction. The present invention has been proposed for the purpose of providing an objective lens driving device that achieves downsizing of the device or improvement in sensitivity characteristics and a recording / reproducing device using the same.
[0027]
[Means for Solving the Problems]
  An objective lens driving device according to the present invention that achieves this object and a recording / reproducing device using the same are as follows.The objective lens, a holder portion to which the objective lens is assembled is formed on one end side, a focusing coil that generates a magnetic driving force acting in a direction parallel to the optical axis of the objective lens, and an objective A bobbin member assembled with a tracking coil that generates a magnetic driving force acting in a direction orthogonal to the optical axis of the lens, and arranged on both side surfaces of the bobbin member in a direction parallel to the optical axis, A plurality of elastic members that support the bobbin member in a focusing direction and a tracking direction so as to be elastically displaceable by fixing the other portion to a bobbin support member that is a fixed portion and a magnet are joined. And a first yoke inserted inside the focusing coil and a first yoke positioned so as to face the tracking coil And a base member configured to fix and support the bobbin support member by forming the yoke to rise, and the plurality of elastic members are each formed of a leaf spring material, and the bobbin support member A first folded piece and a second folded piece connected to each other via a connecting piece formed in a direction orthogonal to the proximal end part, a fitting part attached to the bobbin member, and a fitting part attached to the bobbin member; A folded portion formed by a piece, and an elastically deformable portion formed continuously from the second folded piece between the fitting portion and the second folded piece, and the folded portion Is attached with a dumping agent having viscoelasticity to suppress the resonance phenomenon of the elastic member..
[0028]
Further, in the objective lens driving device and the recording / reproducing device using the same according to the present invention, the first folded piece and the second folded piece are each formed in a direction parallel to the base end portion, and The one folded piece and the base end portion may be connected via a second connecting piece formed in a direction orthogonal to the base end portion to form a second folded portion. .
[0029]
  Furthermore, the objective lens driving device and the recording / reproducing device using the same according to the present invention are:An objective lens, a holder part to which the objective lens is assembled is formed on one end side, a focusing coil that generates a magnetic driving force acting in a direction parallel to the optical axis of the objective lens, and an objective lens on the other end side And a bobbin member assembled with a tracking coil that generates a magnetic driving force acting in a direction perpendicular to the optical axis of each of the two, and arranged on both side surfaces of the bobbin member so as to be separated from each other in a direction parallel to the optical axis. Is fixed to the bobbin support member, which is the fixed portion, and the magnet is joined to a plurality of elastic members that support the bobbin member in a focusing direction and a tracking direction so as to be elastically displaceable. And a first yoke inserted inside the focusing coil and a second yoke positioned so as to face the tracking coil And a base member that constitutes a magnetic circuit portion by a rising formation of a yoke and fixes and supports a bobbin support member, and each of the plurality of elastic members is formed of a leaf spring material, and the bobbin support member A base end portion to be attached, a fitting portion to be attached to the bobbin member, and a first folded piece and a second folded piece connected to each other via a connecting piece formed in a direction orthogonal to the base end portion. And a first folded portion formed between the fitting portion and the second folded piece, and an elastically deformable portion formed continuously with the second folded piece. A dumping agent having viscoelasticity that surrounds the piece and the second folded piece and suppresses resonance of the elastic member is attached.
[0030]
[Action]
According to the objective lens driving device and the recording / reproducing device using the same according to the present invention configured as described above, the elastic member formed with the folded portion is the elastic displacement portion even when the dimensional specifications are the same. A substantial effective length is ensured. Therefore, the objective lens driving device has a primary resonance frequency (f₀) And the sensitivity characteristics are improved, and the size can be reduced.
[0031]
Further, according to the present invention, the dumping agent that suppresses the resonance operation can be assembled in a limited manner at the optimum position, and the shape specification of the folded portion is appropriately selected, so that the elastic member can be resonated and operated. The state of elastic deformation of the elastic member can be adjusted, and the characteristics of the elastic member can be optimized.
[0032]
【Example】
Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. An objective lens driving device 1 according to the present invention is characterized by an elastic member 20 to be described later, and has a leaf spring type structure orthogonal biaxial actuator having a basic configuration substantially the same as that of the conventional objective lens driving device 100 described above. It is an objective lens drive device provided with a mechanism. Therefore, in the following description, the same members as those in the conventional objective lens driving device 100 described above are denoted by the same reference numerals. The objective lens driving device 1 includes four elastic members 20A to 20D as will be described later. However, when these are described in common, they are simply expressed as the elastic member 20.
[0033]
That is, the objective lens driving device 1 includes an objective lens 2, an objective lens holder 3 to which the objective lens 2 is assembled, an objective lens holder 3 and a magnetic circuit unit 4 as shown in FIGS. A bobbin member 5 in which each member to be described later is combined, four elastic members 20 (20A to 20D) which support the bobbin member 5, and a bobbin which supports the base end portion of the elastic member 20 The support member 6 and the base member 7 formed of a magnetic material are configured as main components.
[0034]
The bobbin member 5 is formed of a synthetic resin material, and includes a holder portion 8 to which the above-described objective lens holder 3 is assembled, and a magnetic circuit component assembly portion 9 in which the constituent members of the magnetic circuit portion 4 are combined. . The holder portion 8 is configured as a thin cylindrical portion as a whole provided with an objective lens mounting hole 10 into which the objective lens holder 3 combined with the objective lens 2 is fitted. The holder portion 8 is integrally formed with a plurality of holding pieces 17A to 17C that hold the outer peripheral surface of the objective lens 3 fitted in the objective lens mounting hole 10.
[0035]
The magnetic circuit component assembly portion 9 of the bobbin member 5 is configured as a large opening having a substantially convex shape, and a focusing coil 12 that generates a magnetic driving force that drives and displaces the objective lens 2 in a direction parallel to the optical axis. A pair of tracking coils 13A and 13B for generating a magnetic driving force for driving and displacing the objective lens 2 in a direction orthogonal to the optical axis are assembled. The focusing coil 12 is mounted on the magnetic circuit component mounting portion 9 at a slightly wider opening side opposite to the objective lens mounting hole 10.
[0036]
Horizontal fitting slits 5a into which respective fitting portions 23A to 23D of elastic members 20A to 20D described later are inserted in both side surface portions of the bobbin member 5 corresponding to the magnetic circuit component assembly portion 9. Thru | or the fitting slit 5d are spaced apart and provided in the up-down direction, respectively. Accordingly, the bobbin member 5 is supported by the elastic members 20A to 20D so as to be elastically displaceable in the vertical direction and the horizontal direction.
[0037]
The focusing coil 12 has a rectangular tube shape having substantially the same diameter as the opening dimension of the coil assembly opening portion 11 constituting the magnetic circuit component assembly portion 9, and is fitted into the coil assembly opening portion 11 for assembly. It is done. In addition, the focusing coil 12 is firmly fixed to the bobbin member 5 by being assembled into the coil assembly opening 11 and then filled with an adhesive between the outer peripheral surface and the inner wall of the opening. In addition, the focusing coil 12 is configured such that the winding direction of the coil is a direction orthogonal to the optical axis of the objective lens 2 in a state where the focusing coil 12 is assembled in the coil assembly opening 11.
[0038]
Each of the tracking coils 13A and 13B is configured to have a thin rectangular frame shape, and is positioned between one side surface of the focusing coil 12 and the objective lens so that the one side surface is overlapped with each other. Thus, the magnetic circuit component assembly part 9 is fitted into the coil assembly opening 11 and assembled. These tracking coils 13A and 13B are firmly fixed to one side surface of the focusing coil 12 by an adhesive. The tracking coils 13A and 13B are configured to have linear portions parallel to the optical axis of the objective lens 2 at least on opposite sides when assembled in the magnetic circuit component assembly portion 9.
[0039]
Although the detailed illustration of the base member 7 is omitted, the base member 7 is formed in a substantially H shape by a high magnetic permeability material such as silicon steel, and the first yoke piece 14A is formed from the opposite side edges of the central connecting piece. And the second yoke piece 14B are integrally formed so as to face each other in parallel.
[0040]
The first yoke piece 14 </ b> A passes through the center hole of the focusing coil 12 assembled in the magnetic circuit component assembly part 9. Further, the second yoke piece 14B passes through the magnetic circuit component assembling portion 9 so as to face the tracking coils 13A and 13B. A slightly thick plate-like magnet 15 is firmly attached and fixed to the first yoke piece 14A on the side surface facing the second yoke piece 14B using an adhesive or the like. As shown by a chain line in FIG. 1, a yoke plate 16 formed of a magnetic material is combined with the tip portions of the first yoke piece 14A and the second yoke piece 14B.
[0041]
Therefore, the magnetic circuit unit 4 is attached to the base member 7 described above, the first yoke piece 14A and the second yoke piece 14B that are formed integrally with the base member 7, and the first yoke piece 14A. And a magnet plate 15 and a yoke plate 16. The focusing coil 12 and the tracking coils 13 </ b> A and 13 </ b> B are assembled to the magnetic circuit component assembly unit 9 so as to cross the magnetic field of the magnetic circuit unit 4. In addition, the current is supplied to the focusing coil 12 and the tracking coils 13A and 13B by using the elastic members 20A to 20D as will be described later.
[0042]
The bobbin support member 6 is located on the opposite side of the first yoke piece 14A and the second yoke piece 14B, and is assembled to the base member 7 so as to straddle the central opening portion. That is, the bobbin support member 6 is formed with an inverted U-shaped recess 6a that forms an optical path of a light beam emitted from a semiconductor laser (not shown) on the bottom surface portion, and an elastic member that supports the bobbin member 5 on both side surface portions. The horizontal fitting slits 6b to 6e into which the base end portions 21A to 21D of the elastic members 20A to 20A are respectively inserted are spaced apart in the vertical direction.
[0043]
The elastic members 20A to 20D are members formed by punching a thin spring plate material, and are elastic members 20A and 20B assembled to the left side surface portion of the bobbin support member 6, and elastic members 20C and 20D assembled to the right side surface portion. Are the left and right target shapes, and the elastic members 20A and 20B and the elastic members 20C and 20D assembled to the same side surface have the same shape.
[0044]
If the structure of these elastic members 20 is demonstrated with reference to FIG. 4, the elastic member 20 is a substantially rectangular base inserted in the fitting slit 6b thru | or the fitting slit 6d provided in the both sides | surfaces of the bobbin support member 6, respectively. It is comprised from the edge part 21, the narrow elastic deformation part 22, and the substantially rectangular fitting part 23 each inserted in the fitting slit 5a thru | or the fitting slit 5d provided in the both sides | surfaces of the bobbin member 5. . In the vicinity of the base end portion 21 of the elastic member 20, an L-shaped opening portion 30 and a rectangular opening portion 31 are punched out in a state of being combined with each other, whereby a folded portion 29 having a substantially U-shape as a whole. Is formed.
[0045]
That is, the folded portion 29 is formed from the first folded piece 26 and the second folded piece 28 in a direction parallel to the base end portion 21 connected to each other via a connecting piece 27 in a direction orthogonal to the base end portion 21. It is configured. The second folded piece 28 located on the outside continues to the elastic deformation portion 22 as it is. The other end portion 33 of the base end portion 21 is cut off so as to surround the folded portion 29 and is configured as a lead wire connecting portion.
[0046]
Further, the elastic member 20 is integrally formed with a coil connection piece 24 parallel to the elastic deformation portion 22 on one end side of the fitting portion 23. The coil connection piece 24 is provided with positioning holes 25 corresponding to the hemispherical positioning dowels 32 formed on the upper and lower surfaces of the bobbin member 5.
[0047]
The elastic member 20A to the elastic member 20D are fixed by inserting the base end portion 21A to the base end portion 21D into the fitting slit 6b to the fitting slit 6d provided on both side surfaces of the bobbin support member 6, respectively. Each of the support members 6 is supported in a cantilever state. The elastic members 20A to 20D are fixed by inserting the fitting portions 23A to 23D on the free end side into the fitting slits 5a to 5d provided on both side surfaces of the bobbin member 5, respectively. Thus, the bobbin member 5 is elastically supported in the vertical direction and the horizontal direction.
[0048]
Further, the elastic member 20A to the elastic member 20D have the positioning hole 25 of the coil connection piece 24 of the bobbin member 5 in a state where the bobbin member 5 is elastically supported by the bobbin support member 6 and is combined between these two members. The positioning dowels 32 are relatively engaged with each other. The coil connecting piece 24 is connected with the coil wires of the focusing coil 12 and the tracking coils 13A and 13B. The lead wire connecting portion 33 of the base end portion 21 is connected to a lead wire that connects the focusing coil 12 and a driving source that supplies a driving current to the tracking coils 13A and 13B. Therefore, the elastic member 20 also functions as a current supply line to the focusing coil 12 and the tracking coils 13A and 13B.
[0049]
The optical pickup device including the objective lens driving device 1 configured as described above irradiates the information recording surface of the optical disc with the light beam emitted from the semiconductor laser via the objective lens 2, and from the information recording surface. The reflected light is dispersed by the beam splitter through the objective lens 2 and the difference between the focusing direction and the tracking direction is detected by the detector. The detected misalignment between the focusing direction and the tracking direction is processed by the servo circuit as a focus error signal or a tracking error signal, and a drive current corresponding to them is supplied to the focusing coil 12 and the tracking coils 13A and 13B.
[0050]
When the driving current corresponding to the focus error signal is supplied to the focusing coil 12, the objective lens driving device 1 uses the current flowing in the focusing coil 12 and the magnetic flux from the magnet 15 constituting the magnetic circuit unit 4 to generate a bobbin. A magnetic driving force for driving the member 5 in the focusing direction is generated. This magnetic driving force is a semiconductor that irradiates an optical disc by elastically displacing the elastic members 20A to 20D in the vertical direction and adjusting the bobbin member 5, in other words, the objective lens 2 in a focusing direction parallel to the optical axis. Adjust the laser focusing.
[0051]
When the objective lens driving device 1 is supplied with a driving current corresponding to the tracking error signal to the first tracking coil 13A or the second tracking coil 13B, the current flowing through the tracking coils 13A and 13B and the magnetic circuit unit The magnetic driving force for driving the bobbin member 5 in the tracking direction is generated by the magnetic flux from the magnet 15 constituting the motor 4. This magnetic driving force irradiates the optical disk by elastically displacing the elastic member 20A to elastic member 20D in the left-right direction and adjusting the bobbin member 5, in other words, the objective lens 2 in the tracking direction orthogonal to the optical axis. The tracking of the semiconductor laser is adjusted.
[0052]
As described above, the elastic member 20 has the primary resonance frequency (f₀) Is expressed by Formula 1. The elastic member 20 is formed by forming the folded portion 29 so that the length of the elastically deformed portion becomes (L1 + L2) and is substantially larger than that of the conventional elastic member. Of course, this length dimension (L1 + L2) is equal to the primary resonance frequency (f₀This is not applied by replacing L in Formula 1 for calculating) as it is. Therefore, in the objective lens driving device 1, the elastic deformation effective length L0 is calculated using the finite element method (FEM) under the following conditions.
[0053]
That is, the elastic member 20 is assumed to be formed with the dimensions of each part in FIG.
[0054]
  Thickness dimension: t = 0.07 mm (provided that the whole is uniform)
Total length of the elastic deformation portion 22 including the second folded piece 28: L1 = 9.8 mm
Length dimension of the first folded piece 26: L2 = 2.0 mm Width dimension b1 of the elastically deformable portion 22 and width dimension b3 of the second folded piece 28: b1 = b3 = 0.09 mm
Width dimension of the first folded piece 26: b2 = 0.15mm
Mass of movable part: M = 0.24 g
Young's modulus E = 1.12 × 10^-11N /m ² (Load / Cross-sectional area)
From the above conditions, the primary resonance frequency (f₀) Is about 35 Hz, and the primary resonance frequency (f₀) Is 47 Hz.
[0055]
Here, assuming that the width dimension b2 = 0.15 mm of the first folded piece 26 is the same as the width dimension b1 of the elastic deformation portion 22, and calculating the elastic deformation effective length L0 from Equation 1, the focusing direction is as follows. Is 10.6 mm and the tracking direction is 10.3 mm.
[0056]
Therefore, the objective lens driving device 1 includes the elastic member 20 having the folded portion 29, so that the elastic deformation effective length dimension L0 is 10 in the focusing direction as compared with the elastic member not having the folded portion 29. When 6 mm−9.8 mm = 0.8 mm, it is increased by about 8%, and for the tracking direction, it is increased by about 5% when 10.3 mm−9.8 mm = 0.5 mm. Further, the primary resonance frequency (f₀) Is reduced by about 12% at about 5 Hz.
[0057]
As described above, according to the objective lens driving device 1, the folded portion 29 is formed on the elastic member 20, so that the actual length dimension of the elastic member 20 remains the same and the primary resonance frequency (f₀) Can be reduced.
[0058]
FIG. 5 shows another example of the elastic member, and this elastic member 40 is formed in substantially the same basic configuration as the elastic member 20 described above, but the second folded back outside constituting the folded portion 49. It is characterized in that a crank-like connecting portion 53 is formed on a part of the piece 48. That is, the elastic member 40 includes a substantially rectangular base end portion 41 inserted into the fitting slit 6b to the fitting slit 6d provided on both side surface portions of the bobbin support member 6, and an elastic deformation portion 42 having a narrow width. , And a substantially rectangular fitting portion 43 inserted into the fitting slit 5a to the fitting slit 5d provided on both side surface portions of the bobbin member 5. The base end portion 41 is formed with a folded portion 49 that is substantially U-shaped as a whole by punching out the L-shaped opening 50 and the substantially crank-shaped opening 51 in a state of being combined with each other. .
[0059]
The turned-up portions 49 are connected to each other via a connecting piece 47 in a direction orthogonal to the base end portion 41, and the first turned-up piece 46 located on the inner side in the direction parallel to the base end portion 41 and the second turned on the outer side. And the folded piece 48. The second folded piece 48 is connected to the elastic deformation portion 42 via a crank-shaped connecting portion 53 formed by the opening 51. The other end portion 52 of the base end portion 41 is configured to be a lead wire connecting portion by being left uncut so as to surround the folded portion 49.
[0060]
The elastic member 40 is integrally formed with a coil connection piece 44 parallel to the elastic deformation portion 42 on one end side of the fitting portion 43, and the coil connection piece 44 is formed on the upper and lower surfaces of the bobbin member 5. Positioning holes 45 are provided corresponding to the formed hemispherical positioning dowels 32.
[0061]
As described above, the elastic member 40 constituting the objective lens driving device is fixed by inserting the base end portion 41 into the fitting slit 6b to the fitting slit 6d provided on both side surfaces of the bobbin support member 6, respectively. The bobbin support member 6 is supported in a cantilevered state. Further, the elastic member 40 is inserted into and fixed to the fitting slits 5a to 5d provided on the both side surface portions of the bobbin member 5 by the fitting portions 43 on the free end side. Elastically supported in the vertical and horizontal directions.
[0062]
Further, in the elastic member 40, the positioning hole 45 of the coil connection piece 44 is formed in the positioning dowel 32 of the bobbin member 5 in a state where the elastic member 40 is combined between these two members so as to elastically support the bobbin member 5 to the bobbin support member 6. Each is relatively engaged. The coil connection piece 44 is connected to the coil wires of the focusing coil 12 and the tracking coils 13A and 13B. Further, the lead wire connecting portion 52 of the base end portion 41 is connected to a lead wire that connects the focusing coil 12 and a driving source that supplies a driving current to the tracking coils 13A and 13B. Therefore, the elastic member 40 also functions as a current supply line to the focusing coil 12 and the tracking coils 13A and 13B.
[0063]
As described above, the elastic member 40 in which the substantially crank-shaped connecting portion 53 is formed in the turned-up portion 49 has the substantial length dimension of the elastic deformation portion increased and is elastically displaced in the focusing direction or the tracking direction. Therefore, it is possible to suppress the resonance phenomenon that occurs when the vibration occurs, or to improve the efficiency of the damping action that promptly attenuates the vibration.
[0064]
FIG. 6 shows another embodiment of the elastic member, and this elastic member 60 is formed in substantially the same basic configuration as the elastic member 20 described above, but a part of the range of the dimension L in FIG. It is characterized in that it has a folded portion 66 formed in place of the dimension L2 in FIG. That is, the elastic member 60 is formed by dividing a base end portion side elastic deformation portion 61A and a fitting portion side elastic deformation portion 61B by providing a notch 65 in a part of the elastic deformation portion 61. The side elastic deformation part 61 </ b> A and the fitting part side elastic deformation part 61 </ b> B are configured by a substantially convex folded part 66.
[0065]
The folded portion 66 includes a first base end side connecting piece 62A whose base end side portion is continuously provided in a direction orthogonal to the tip of the base end side elastic deformation portion 61A, and the base end side connecting piece 62A. The first base end side folded piece 63A provided in a direction returning from the tip of the base end side to the base end side in parallel with the base end side elastic deformation portion 61A, and the first base end side folded piece 63A 64A of 2nd base end part side connection pieces provided in a direction further orthogonal from the front-end | tip of this.
[0066]
Further, the folded portion 66 includes a first fitting portion side connecting piece 62B having a fitting portion side continuously provided in a direction orthogonal to the tip of the fitting portion side elastically deforming portion 61B, and the fitting portion side connecting piece. A first fitting portion side folding piece 63B provided in a direction returning from the tip of 62B to the fitting portion side in parallel with the fitting portion side elastic deformation portion 61B, and the first fitting portion side folding piece It is comprised from the 2nd fitting part side connection piece 64B continuously provided in the direction orthogonal to the front-end | tip of 63B.
[0067]
In the folded portion 66, a second folded piece 65A parallel to the elastically deforming portion 61 is connected between the second base end side connecting piece 64A and the second fitting portion side connecting piece 64B. Thus, as described above, the overall configuration is substantially convex. In addition, since the folding | returning part 66 makes other structures, such as a base end part or a fitting part, substantially the same as the elastic member 20 mentioned above, the description is abbreviate | omitted. As described above, the elastic member 60 is formed with the folded portion 66 having the above-described configuration, so that the elastically deformable portion has the first base end side folded piece 63A, the first fitting portion side folded piece 63B, and the first folded portion 63B. The length is obtained by adding the second folded piece 65A, and is further enlarged.
[0068]
7 to 9, the FEM analysis was performed on the elastic member 70 in which the crank-shaped bent portion 73 was formed and the width of the base end 72 was made larger than the width of the elastic deformation portion 72. It is the figure which showed typically the resonance phenomenon of rolling around the Z-axis (focusing direction) in the case. 10 to 12 show a Z-axis (focusing direction) when an FEM analysis is performed on an elastic member 75 having a U-shaped folded portion 76 and formed with substantially the same width. It is the figure which showed typically the resonance phenomenon of rolling. In these drawings, the X axis indicates the longitudinal direction of the elastic deformation portion 72 of the elastic member 70, and the Y axis indicates the tracking direction.
[0069]
As is apparent from FIGS. 7 to 9, in the elastic member 70, the base end portion 71 is greatly deformed against the rolling phenomenon around the Z axis, and the elastic deformation portion 72 is also largely deformed in the vicinity of the base end portion 71. Therefore, with respect to the elastic member 70 shown in FIGS. 7 to 9, it is judged that it is effective to attach the dumping agent over the entire elastic deformation portion 72 having a large deformation state as a countermeasure for suppressing the resonance phenomenon. . In other words, since the dumping agent is attached to the elastic member 70 over the entire elastic deformation portion 72, for example, the mass characteristics of the elastic member 70 are also greatly changed.
[0070]
On the other hand, as is apparent from FIGS. 10 to 12, the elastic member 75 is significantly deformed in the vicinity of the folded portion 76 with respect to the rolling phenomenon around the Z axis. Therefore, with respect to the elastic member 75 having the folded portion 76, it is determined that it is effective to attach the dumping agent 80 to the folded portion 76 having a large deformation state, as shown in FIG. . Then, the elastic member 75 having the dumping agent 80 attached to the folded portion 76 is formed on the bobbin support member 6 in which the attaching portions 6A to 6D are recessed in parallel with the elastic member 75, as shown in FIGS. It is attached.
[0071]
Moreover, about the elastic member 60 mentioned above, as shown to FIG. 16 (A), each piece is straddled across the base end part side elastic deformation part 61A and the fitting part side elastic deformation part 61B in the folding | returning part 66. FIG. The dumping agent 80 is attached so as to surround it. Further, as shown in FIG. 16B, the folded portion 66 of the elastic member 60 includes a first base end portion side folded piece 63A, a first fitting portion side folded piece 63B, and a second base end. The dumping agent 80 may be attached across the part side connecting piece 64A, the second fitting part side connecting piece 64B, and the second folded piece 65A.
[0072]
As described above, in the elastic member in which the folded portion is formed, the dumping agent that restricts the resonance phenomenon is limited, i.e., the dumping agent is limited so as to surround each parallel piece constituting the folded portion. You can attach it. Therefore, the elastic member can be easily attached with the dumping agent, and the characteristic does not change greatly due to the attachment.
[0073]
On the other hand, in the objective lens driving device 1, the primary resonance frequency (f₀The degree of occurrence Q of the resonance phenomenon in the value is one of important parameters that determine the basic characteristics of the objective lens driving device 1. As shown in FIG. 17, the degree of occurrence Q of the resonance phenomenon is expressed by the primary resonance frequency (f₀) This is because of a rapid gain increase near the value, and a smaller value is preferable in the objective lens driving device 1. The occurrence degree Q of the resonance phenomenon can be reduced by attaching a dumping agent to a place where the deformation state of the elastic member where the resonance phenomenon occurs is remarkable.
[0074]
18 to 20 show the primary resonance frequency (f) in the focusing direction when the FEM analysis is performed on the elastic member 20 having the folded portion 29 described above.₀It is the figure which showed typically the deformation | transformation state at the time of resonance in value. 21 to 23 show the primary resonance frequency (f) in the tracking direction when the FEM analysis is performed on the elastic member 20 having the folded portion 29.₀It is the figure which showed typically the deformation | transformation state at the time of resonance in value.
[0075]
As is clear from these drawings, the elastic member 20 in which the folded portion 29 is formed in the vicinity of the base end portion 21 has greatly different deformation states in the X-axis direction of the elastic deformation portion 22 at both ends. That is, the elastic member 20 hardly deforms on the side of the fitting portion 23 that is the connecting portion with the bobbin member 5, but large deformation occurs at the base end portion 21 that is the connecting portion with the bobbin support member 6. To do. Therefore, it is apparent that the folded portion 29 is suitable for the elastic member 20 as a portion where a dumping agent that suppresses the resonance phenomenon is attached.
[0076]
  Conventional elastic member 10 having no folded portion in the vicinity of the base end portion1In FIG. 20, the deformation phenomenon in the vicinity of the base end shown by the region A in FIG. 20 is extremely small. For this reason, the elastic member 101It is extremely difficult to find the location where the dumping agent is attached to suppress the resonance phenomenon. In other words, the elastic member 20 forms the primary resonance frequency (f) by forming the folded portion 29 in the vicinity of the base end portion 21.₀) A dump near the value can be easily realized, and the degree of occurrence Q of the resonance phenomenon can be reduced.
[0077]
Here, as the dumping agent attached to the elastic member, a synthetic resin material having viscoelasticity such as butyl or rubber, which has a large damping characteristic, is generally used. For example, when an ultraviolet curable synthetic resin is used. Can obtain a desired viscoelastic modulus by controlling the irradiation amount of ultraviolet rays, and is extremely effective.
[0078]
In addition, this invention is not limited to each elastic member mentioned above, Furthermore, it develops variously. That is, the folded portion formed in the vicinity of the base end portion is in a plane constituted by the X axis that is the longitudinal direction of the elastic deformation portion and the Y axis that is the tracking direction, in other words, in a plane parallel to the base member. In this case, it may be configured as a part that is continuously folded in a substantially U shape at least at one place with respect to the X-axis direction. The length dimension, width dimension, number of folded parts, etc. It is set according to the design conditions of the objective lens driving device, such as the application method. In the elastic member having a width dimension in the direction perpendicular to the base member, the above-described folded portion is formed in the plane constituted by the Y axis that is the tracking direction and the Z axis that is the focusing direction. It is.
[0079]
【The invention's effect】
According to the objective lens driving device and the recording / reproducing device using the same according to the present invention, the plurality of elastic members are each formed of a leaf spring material and are substantially U-shaped in a plane parallel to the base member at least at one place. By forming the folded portion in which the folded portions are continuously formed, the primary resonance frequency value is reduced, and the device is downsized or the frequency characteristics are improved.
[0080]
Further, according to the objective lens driving device and the recording / reproducing device using the same according to the present invention, the plurality of elastic members are each formed of a leaf spring material and are substantially in a plane parallel to the base member in at least one place. A folded part is formed in which U-shaped folded parts are continuously formed, and a dumping agent is attached to surround each parallel piece constituting the folded part and suppress the resonance of the elastic member. As a result, the primary resonance frequency value can be reduced, the device can be downsized or the frequency characteristics can be improved, and the occurrence of the resonance phenomenon can be reduced.
[Brief description of the drawings]
FIG. 1 is an overall perspective view showing an objective lens driving apparatus according to the present invention.
FIG. 2 is an overall plan view of the objective lens driving device.
FIG. 3 is an overall side view of the objective lens driving device.
FIG. 4 is a perspective view in which a part of an elastic member constituting the biaxial actuator provided in the objective lens driving device and movably supporting the objective lens in a focusing direction and a tracking direction is omitted.
FIG. 5 is a perspective view showing an example of an elastic member with a part thereof omitted.
FIG. 6 is a perspective view showing only an essential part of an example of an elastic member.
FIG. 7 is a diagram schematically showing an elastic deformation state at the time of resonance from the three-dimensional direction when an FEM analysis is performed on an elastic member having a base end that is wide.
FIG. 8 schematically shows an elastic deformation state at the time of resonance between the X-axis direction that is the longitudinal direction of the elastic deformation portion and the Y-axis direction that is the tracking direction when FEM analysis is performed on the elastic member. It is a figure.
FIG. 9 schematically shows an elastic deformation state at the time of resonance between the X-axis direction that is the longitudinal direction of the elastic deformation portion and the Z-axis direction that is the focusing direction when FEM analysis is performed on the elastic member. It is a figure.
FIG. 10 is a diagram schematically showing a state of elastic deformation at the time of resonance when an FEM analysis is performed on an elastic member in which a folded portion is formed in the vicinity of a base end portion from a three-dimensional direction.
FIG. 11 schematically shows an elastic deformation state at the time of resonance between the X-axis direction that is the longitudinal direction of the elastic deformation portion and the Y-axis direction that is the tracking direction when FEM analysis is performed on the elastic member. It is a figure.
FIG. 12 schematically shows an elastic deformation state at the time of resonance between the X-axis direction that is the longitudinal direction of the elastic deformation portion and the Z-axis direction that is the focusing direction when FEM analysis is performed on the elastic member. It is a figure.
FIG. 13 is a plan view of an essential part for explaining the position of the dumping agent attached to the elastic member.
FIG. 14 is a side view of an essential part for explaining the position of a dumping agent attached to an elastic member.
FIG. 15 is a front view for explaining the position of the dumping agent attached to the elastic member.
FIG. 16 is a perspective view of an essential part for explaining the position of a dumping agent attached to an elastic member.
FIG. 17 is a diagram schematically showing frequency characteristics of an elastic member in a focusing direction, and shows a primary resonance frequency (f₀It is a characteristic diagram of the resonance degree Q in the vicinity.
FIG. 18 shows a primary resonance frequency (f) in a focusing direction when FEM analysis is performed on an elastic member in which a folded portion is formed in the vicinity of a base end portion.₀It is the figure which showed typically the elastic deformation state in value from a three-dimensional direction.
FIG. 19 schematically shows an elastic deformation state at the time of resonance between the X-axis direction that is the longitudinal direction of the elastic deformation portion and the Y-axis direction that is the tracking direction when FEM analysis is performed on the elastic member. It is a figure.
FIG. 20 schematically shows an elastic deformation state at the time of resonance between the X-axis direction that is the longitudinal direction of the elastic deformation portion and the Z-axis direction that is the focusing direction when the FEM analysis is performed on the elastic member. It is a figure.
FIG. 21 shows a primary resonance frequency (f) in a tracking direction when FEM analysis is performed on an elastic member having a folded portion in the vicinity of a base end portion.₀It is the figure which showed typically the elastic deformation state in value from a three-dimensional direction.
FIG. 22 schematically shows an elastic deformation state at the time of resonance between the X-axis direction which is the longitudinal direction of the elastic deformation portion and the Y-axis direction which is the tracking direction when FEM analysis is performed on the elastic member. It is a figure.
FIG. 23 schematically shows an elastic deformation state at the time of resonance between the X-axis direction that is the longitudinal direction of the elastic deformation portion and the Z-axis direction that is the focusing direction when FEM analysis is performed on the elastic member. It is a figure.
FIG. 24 is an overall perspective view showing a conventional objective lens driving device.
FIG. 25 is a perspective view of an elastic member provided in a conventional objective lens driving device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Objective lens drive device, 2 Objective lens, 5 Bobbin member, 6 Bobbin support member, 7 Base member, 8 Holder part, 9 Magnetic circuit component assembly part, 11 Coil assembly opening part, 12 Focusing coil, 13 Tracking coil, 14 Yoke, 15 Magnet, 20 Elastic member, 21 Base end portion, 22 Elastic deformation portion, 23 Fitting portion, 26 First folding piece, 28 Second folding piece, 29 Folding portion, 80 Dump agent

Claims (6)

An objective lens;
Together with the holder unit the objective lens is assembled on one end side is formed, a focusing coil for generating a magnetic driving force acting in a direction parallel to the optical axis of the objective lens at the other end, and the optical axis of the objective lens A bobbin member assembled with a tracking coil that generates a magnetic driving force acting in an orthogonal direction;
The bobbin member is arranged on both side surfaces of the bobbin member so as to be separated from each other in a direction parallel to the optical axis. And a plurality of elastic members that are elastically displaced in the tracking direction,
A magnet is joined and a first yoke inserted inside the focusing coil and a second yoke positioned so as to face the tracking coil are formed to form a magnetic circuit unit, and A base member for fixing and supporting the bobbin support member,
Each of the plurality of elastic members is formed of a leaf spring material, and is formed in a direction orthogonal to the base end portion, a base end portion attached to the bobbin support member, a fitting portion attached to the bobbin member. A folded portion formed by the first folded piece and the second folded piece connected to each other via the connected piece, and the second folded portion between the fitting portion and the second folded piece. An elastic deformation part formed continuously on the piece,
An objective lens driving device in which a dumping agent having viscoelasticity that suppresses a resonance phenomenon of the elastic member is attached to the folded portion . The first folded piece and the second folded piece are each formed in a direction parallel to the base end,
  The first folded piece and the base end part are connected via a second connecting piece formed in a direction orthogonal to the base end part to form a second folded part. The objective lens driving device according to claim 1. An objective lens;
Together with the holder unit the objective lens is assembled on one end side is formed, a focusing coil for generating a magnetic driving force acting in a direction parallel to the optical axis of the objective lens at the other end, and the optical axis of the objective lens A bobbin member assembled with a tracking coil that generates a magnetic driving force acting in an orthogonal direction;
The bobbin member is arranged on both side surfaces of the bobbin member so as to be separated from each other in a direction parallel to the optical axis. And a plurality of elastic members that are elastically displaced in the tracking direction,
A magnet is joined and a first yoke inserted inside the focusing coil and a second yoke positioned so as to face the tracking coil are formed to form a magnetic circuit unit, and A base member for fixing and supporting the bobbin support member,
Each of the plurality of elastic members is formed of a leaf spring material, and is formed in a direction orthogonal to the base end portion, a base end portion attached to the bobbin support member, a fitting portion attached to the bobbin member. A folded portion formed by the first folded piece and the second folded piece connected to each other via the connected piece, and the second folded portion between the fitting portion and the second folded piece. An elastic deformation part formed continuously on the piece,
An objective lens driving device damping agent has been impregnated with suppressing viscoelasticity resonance of the elastic member surrounds the first folded piece and the second folded piece. An objective lens;
Together with the holder unit the objective lens is assembled on one end side is formed, a focusing coil for generating a magnetic driving force acting in a direction parallel to the optical axis of the objective lens at the other end, and the optical axis of the objective lens A bobbin member assembled with a tracking coil that generates a magnetic driving force acting in an orthogonal direction;
The bobbin member is arranged on both side surfaces of the bobbin member so as to be separated from each other in a direction parallel to the optical axis. And a plurality of elastic members that are elastically displaced in the tracking direction,
A magnet is joined and a first yoke inserted inside the focusing coil and a second yoke positioned so as to face the tracking coil are formed to form a magnetic circuit unit, and A base member for fixing and supporting the bobbin support member,
Each of the plurality of elastic members is formed of a leaf spring material, and is formed in a direction orthogonal to the base end portion, a base end portion attached to the bobbin support member, a fitting portion attached to the bobbin member. A folded portion formed by the first folded piece and the second folded piece connected to each other via the connected piece, and the second folded portion between the fitting portion and the second folded piece. An elastic deformation part formed continuously on the piece,
A recording / reproducing apparatus having an objective lens driving device in which a dumping agent having viscoelasticity that suppresses a resonance phenomenon of the elastic member is attached to the folded portion . The first folded piece and the second folded piece are each formed in a direction parallel to the base end ,
The first folded piece and the base end part are connected via a second connecting piece formed in a direction orthogonal to the base end part to form a second folded part. The recording / reproducing apparatus according to claim 4. An objective lens;
Together with the holder unit the objective lens is assembled on one end side is formed, a focusing coil for generating a magnetic driving force acting in a direction parallel to the optical axis of the objective lens at the other end, and the optical axis of the objective lens A bobbin member assembled with a tracking coil that generates a magnetic driving force acting in an orthogonal direction;
The bobbin member is arranged on both side surfaces of the bobbin member so as to be separated from each other in a direction parallel to the optical axis. And a plurality of elastic members that are elastically displaced in the tracking direction,
A magnet is joined and a first yoke inserted inside the focusing coil and a second yoke positioned so as to face the tracking coil are formed to form a magnetic circuit unit, and A base member for fixing and supporting the bobbin support member,
Each of the plurality of elastic members is formed of a leaf spring material, and is formed in a direction orthogonal to the base end portion, a base end portion attached to the bobbin support member, a fitting portion attached to the bobbin member. A folded portion formed by the first folded piece and the second folded piece connected to each other via the connected piece, and the second folded portion between the fitting portion and the second folded piece. An elastic deformation part formed continuously on the piece,
Recording and reproducing apparatus having an objective lens driving device damping agent has been impregnated with suppressing viscoelasticity resonance of the first folded piece and the second folded piece the elastic member surrounds the.

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