JP2004265501A

JP2004265501A - Optical disk device

Info

Publication number: JP2004265501A
Application number: JP2003053865A
Authority: JP
Inventors: Hiroyuki Matsushima; 裕之松島; Masamichi Ito; 正道伊藤
Original assignee: Hitachi LG Data Storage Inc
Current assignee: Hitachi LG Data Storage Inc
Priority date: 2003-02-28
Filing date: 2003-02-28
Publication date: 2004-09-24

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology for obtaining a lens shifting amount detection output whose fluctuation amount by temperature is compensated for from a position sensor even when a temperature change occurs in an optical disk device. <P>SOLUTION: This optical disk device is constructed in such a manner that the lens shifting amount detection output of a position sensor 50 is corrected by a calculated correction amount based on the output of a temperature sensor 12 for detecting the temperature or the temperature change of the position sensor 50, or the amplitude of the lens shifting amount detection output of the position sensor, and the offset of a tracking error signal is corrected in the corrected state of the error of the temperature change of the position sensor. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、光ディスク装置におけるトラッキング誤差信号のオフセット補正技術に関する。
【０００２】
【従来の技術】
本発明に関連した従来技術としては例えば、特開平６−４４５８７号公報（特許文献１）や特開平７−２３５０６４号公報（特許文献２）に記載されたものがある。特開平６−４４５８７号公報には、対物レンズのシフト量を検出し、各エラー信号のオフセットをレンズシフト信号により補正する構成が記載され、特開平７−２３５０６４号公報には、ポジションセンサのオフセットを自動的に補正する技術として、ポジションセンサの一方のフォトディテクタの出力と他方のフォトディテクタの出力とを、減算器に入力し、対物レンズが中立点に位置するとき、該減算器から出力されるポジションセンサの出力がゼロとなるように、ゲイン調整回路のゲインを設定する構成が記載されている。
【０００３】
【特許文献１】
特開平６−４４５８７号公報
【特許文献２】
特開平７−２３５０６４号公報
【０００４】
【発明が解決しようとする課題】
上記従来技術のうち、特開平６−４４５８７号公報記載の技術では、温度によりポジションセンサの感度が変化した場合にはレンズシフト信号が変動し、各エラー信号のオフセット補正が正確に行えないおそれがある。また、特開平７−２３５０６４号公報記載の技術においても、ポジションセンサにおける両フォトディテクタそれぞれの感度が、異なる温度特性で変化した場合には、ポジションセンサ出力のオフセット補正を正確に行えなくなるおそれがある。
本発明の課題点は、上記従来技術の状況に鑑み、光ディスク装置において、温度が変化した場合にも、ポジションセンサからは温度による変動分を補償したレンズシフト量検出出力が得られるようにし、温度変化の影響を抑えた正確なトラッキング動作を可能にすることである。
本発明の目的は、かかる課題点を解決できる技術の提供にある。
【０００５】
【課題を解決するための手段】
上記課題点を解決するために、本発明では、基本的に、光ディスク装置として、ポジションセンサのレンズシフト検出出力を、ポジションセンサの温度もしくは温度変化を検知する温度センサの出力に基づき演算した補正量またはポジションセンサのレンズシフト量検出出力の振幅に基づき演算した補正量により補正し、ポジションセンサの温度変化分の誤差を補正した状態でトラッキング誤差信号のオフセット補正を行う構成とする。
具体的には、光ディスク装置として、
（１）対物レンズ（該当実施例：符号２）のトラッキング方向の変位を検知するポジションセンサ（該当実施例：符号５０）と、該ポジションセンサの温度または温度変化を検知する温度センサ（該当実施例：符号１２）と、上記ポジションセンサの出力から、上記対物レンズの入射光束に対するレンズシフト量に対応した第１の制御信号を形成し、上記温度センサの出力に基づき、温度変化に対応する上記ポジションセンサの出力の補正量を演算し、該演算結果に対応した第２の制御信号を形成し、かつ、該第２の制御信号により上記第１の制御信号を補正する第１の補正手段（該当実施例：符号１５，１６、１７、１８、１９）と、該第１の補正手段の出力に基づき、トラッキング誤差信号の上記レンズシフト量に基づくオフセットを補正する第２の補正手段（該当実施例：符号２０）とを備えた構成とする。
（２）対物レンズ（該当実施例：符号２）のトラッキング方向の変位を検知するポジションセンサ（該当実施例：符号５０）と、該ポジションセンサの出力から上記対物レンズの入射光束に対するレンズシフト量に対応した第１の制御信号を形成し、該ポジションセンサ出力の振幅に基づき温度変化に対応する該ポジションセンサ出力の補正量を演算し該演算結果に対応した第２の制御信号を形成し、該第２の制御信号により上記第１の制御信号を補正する第１の補正手段（該当実施例：符号２２、２４、２５、１７、１８、１９）と、該第１の補正手段の出力に基づきトラッキング誤差信号の上記レンズシフト量に基づくオフセットを補正する第２の補正手段（該当実施例：符号２０）とを備えた構成とする。
（３）対物レンズのトラッキング方向の変位を検知するポジションセンサ（該当実施例：符号５０）と、該ポジションセンサを駆動するセンサ駆動回路（該当実施例：符号２１）と、上記ポジションセンサの出力から上記対物レンズの入射光束に対するレンズシフト量に対応した第１の制御信号を形成し出力するレンズシフト検出回路（該当実施例：符号１８）と、上記ポジションセンサ出力の振幅に基づき温度変化に対応する該ポジションセンサ出力の補正量を演算し該演算結果に対応した第２の制御信号を形成し出力する演算回路（該当実施例：符号２４、２５、１７）と、上記第２の制御信号により上記センサ駆動回路の入力を制御するセンサ入力制御手段（該当実施例：符号３５）と、上記第１の制御信号によりトラッキング誤差信号の上記レンズシフト量に基づくオフセットを補正するオフセット補正手段（該当実施例：符号２６）とを備えた構成とする。
【０００６】
【発明の実施の形態】
以下、本発明の実施例につき、図面を用いて説明する。
図１は、本発明の第１の実施例としての光ディスク装置の構成例を示す図である。本第１の実施例は、温度センサの出力に基づき、ポジションセンサの出力の補正を行う場合の例である。
図１において、１は光ディスク、２は対物レンズ、３は反射ミラー、４はレーザーダイオード、４０はホログラム素子、５、９は受光素子、６はレンズホルダ、７はトラッキング誤差検出回路、８はＬＥＤ等の発光体、１０は、レンズホルダ６に固定され発光体８からの光を反射する反射板、１１は、レンズホルダ６を介し対物レンズ２を駆動するアクチュエータである。発光体８と受光素子９（厳密には、発光体８と受光素子９と反射板１０）は、対物レンズ２のトラッキング方向の変位を検知するポジションセンサ５０を構成し、発光体８から出射された光を反射板１０で反射し、該反射光を受光素子９が受光し電気信号に変換する。１２は、該ポジションセンサ（発光体８と受光素子９、または発光体８と受光素子９と反射板１０を含む部分）の温度または温度変化を検知する温度センサ、１３は支持体としてのキャリッジ、１４はアクチュエータ１１を駆動するアクチュエータ駆動回路、１５は、温度センサ１２の出力に基づき、温度変化に対応するポジションセンサ５０の出力の補正量を演算し最適化させた制御信号として出力する乗算手段、１６は、基準時と温度変化時のポジションセンサ５０の中立点の電圧レベルを記録する記録手段、１７は、温度によるポジションセンサ５０の感度を計算し、これに基づき上記乗算手段１５での演算係数を決定する計算手段、１８は、ポジションセンサ５０の出力から対物レンズ２の入射光束に対するレンズシフト量を検出し、これに対応した制御信号を形成して出力するレンズシフト検出回路、１９は、乗算手段１５からの出力とレンズシフト検出回路１８からの出力とを加算（または減算）し、レンズシフト検出回路１８からの出力をポジションセンサ５０の温度変化分誤差を補正した出力とする第１の加算手段、２０は、該第１の加算手段の出力とトラッキング誤差検出回路７の出力とを加算（または減算）し、トラッキング誤差検出回路７からの出力（トラッキング誤差信号）を、上記レンズシフトに基づくオフセットを補正した出力とする第２の加算手段である。第１の加算手段からは、ポジションセンサ５０の温度変化分誤差を補正したレンズシフト検出出力が得られ、第２の加算手段からは、上記レンズシフトに基づくオフセットを補正したトラッキング誤差信号が得られる。
【０００７】
上記構成において、情報の記録または再生時に、光ピックアップ内においてレーザーダイオード４から出たレーザー光は、反射ミラー３で反射され、対物レンズ２で収束されて、光ディスク１上の記録面に光スポットを形成する。対物レンズ２は、アクチュエータ１１により駆動され、トラッキング方向の変位により所定のトラッキング動作を行う。このとき、該対物レンズ２の入射光束に対するレンズシフトに伴って、トラッキング制御用のトラッキング誤差信号にオフセットが発生する。該レンズシフトに基づくトラッキング誤差信号のオフセットは、レンズシフト検出回路１８の出力を、乗算手段１５からの出力で補正し、該補正出力により取除くようにする。すなわち、対物レンズ２のレンズシフト量に対応してレンズシフト検出回路１８で形成した第１の制御信号を、さらに、温度センサ１２の出力に基づき乗算手段１５による演算結果から得られる第２の制御信号により補正することで、レンズシフト検出回路１８からの出力をポジションセンサ５０の温度変化分誤差を補正した出力とし、該出力によりトラッキング誤差信号のオフセットを補正するようにする。オフセット補正されたトラッキング誤差信号はアクチュエータ駆動回路１４に入力される。アクチュエータ駆動回路１４はアクチュエータ１１を駆動し、レンズホルダ６を介して対物レンズ２のトラッキング方向の変位を制御してトラッキング動作させる。
【０００８】
上記第１の実施例によれば、光ディスク装置において、ポジションセンサ５０の温度変化分誤差を補正した状態でトラッキング動作を行うことができるため、装置の使用環境や装置内で温度変化が発生した場合にも、記録または再生動作時に、正確なトラッキング動作が可能となる。
【０００９】
図２は、本発明の第２の実施例としての光ディスク装置の構成例を示す図である。本第２の実施例は、温度変化に対応したポジションセンサ出力の振幅変化に基づき、ポジションセンサの出力の補正を行う場合の例である。
図２において、２は対物レンズ、７はトラッキング誤差検出回路、８は、対物レンズ２のトラッキング方向の変位を検知するポジションセンサ５０を構成する発光体、９は同じくポジションセンサ５０を構成する受光素子、１１は、レンズホルダ（図示なし）を介して対物レンズ２を駆動するアクチュエータ、１４は、アクチュエータ１１を駆動するアクチュエータ駆動回路、２１は、発光体８を駆動する発光体駆動回路、２２は正弦波信号を発生する正弦波発生回路、２３は、発光体駆動回路２１の出力に正弦波発生回路２２からの正弦波信号を加算する正弦波信号加算手段、１８は、ポジションセンサ５０の出力から対物レンズ２の入射光束に対するレンズシフト量を検出し、これに対応した制御信号を形成して出力するレンズシフト検出回路、２４は、受光素子９の出力から正弦波信号の振幅を検出する正弦波振幅検出回路、２５は、常温時等の基準時と温度変化時において正弦波振幅検出回路２４から出力される正弦波信号出力の振幅に対応した電圧レベルを記憶する振幅記憶手段、１７は、正弦波信号の振幅に基づき、温度によるポジションセンサ５０の感度を計算し、該計算結果に基づきレンズシフト検出回路１８の出力を補正する制御信号を形成する計算手段、１９は、計算手段１７からの出力とレンズシフト検出回路１８からの出力とを加算（または減算）し、レンズシフト検出回路１８からの出力をポジションセンサ５０の温度変化分誤差を補正した出力とする第１の加算手段、２０は、該第１の加算手段の出力とトラッキング誤差検出回路７の出力とを加算（または減算）し、トラッキング誤差検出回路７からの出力（トラッキング誤差信号）を、上記レンズシフトに基づくオフセットを補正した出力とする第２の加算手段である。第１の加算手段１９からは、ポジションセンサ５０の温度変化分誤差を補正したレンズシフト検出出力が得られ、第２の加算手段２０からは、上記レンズシフトに基づくオフセットを補正したトラッキング誤差信号が得られる。
【００１０】
上記構成において、上記第１の実施例の場合と同様、情報の記録または再生時に、光ピックアップ（図示なし）内においてレーザーダイオード（図示なし）から出たレーザー光は、対物レンズ２で収束されて、光ディスク（図示なし）上の記録面に光スポットを形成する。対物レンズ２は、アクチュエータ１１により駆動され、トラッキング方向の変位により所定のトラッキング動作を行うが、このとき、該対物レンズ２の入射光束に対するレンズシフトに基づき発生するトラッキング誤差信号のオフセットは、レンズシフト検出回路１８の出力を、計算手段１７からの出力で補正することで取除くことができる。すなわち、対物レンズ２のレンズシフト量に対応してレンズシフト検出回路１８で形成した第１の制御信号を、さらに、正弦波振幅検出回路２４の出力に基づき計算手段１７による演算結果から得られる第２の制御信号により補正することで、レンズシフト検出回路１８からの出力をポジションセンサ５０の温度変化分誤差を補正した出力とし、該出力によりトラッキング誤差信号のオフセットを補正する。オフセット補正されたトラッキング誤差信号はアクチュエータ駆動回路１４に入力され、アクチュエータ駆動回路１４はアクチュエータ１１を駆動して、対物レンズ２のトラッキング方向の変位を制御してトラッキング動作させる。
【００１１】
上記第２の実施例によれば、光ディスク装置において、ポジションセンサ５０の温度変化分誤差を補正した状態でトラッキング動作を行うことができるため、装置の使用環境や装置内で温度変化が発生した場合にも、記録または再生動作時に、正確なトラッキング動作が可能となる。特に、本実施例構成では、光ピックアップの小型・軽量化や、生産性の向上、低コスト化などが図り易くなる。また、温度変化に基づくポジションセンサ５０の誤差を一層正確に検出することが可能となり、付随的に一層高精度のトラッキングが可能となる。
【００１２】
図３は、本発明の第３の実施例としての光ディスク装置の構成例を示す図である。本第３の実施例は、温度変化に対応したポジションセンサ出力の振幅変化に基づき、ポジションセンサの温度変化時の感度を計算し、該計算結果をポジションセンサの駆動側にフィードバックする場合の例である。
図３において、２は対物レンズ、７はトラッキング誤差検出回路、８は、ポジションセンサ５０を構成する発光体、９は同じくポジションセンサ５０を構成する受光素子、１１は、対物レンズ２を駆動するアクチュエータ、１４は、アクチュエータ１１を駆動するアクチュエータ駆動回路、２１は、発光体８を駆動する発光体駆動回路、２２は正弦波信号を発生する正弦波発生回路、２３は、発光体駆動回路２１の出力に正弦波発生回路２２からの正弦波信号を加算する正弦波信号加算手段、１８は、ポジションセンサ５０の出力から対物レンズ２の入射光束に対するレンズシフト量を検出し、これに対応した制御信号を形成して出力するレンズシフト検出回路、２４は、受光素子９の出力から正弦波信号の振幅を検出する正弦波振幅検出回路、２５は、常温時等の基準時と温度変化時において正弦波振幅検出回路２４から出力される正弦波信号出力の振幅に対応した電圧レベルを記憶する振幅記憶手段、１７は、正弦波振幅検出回路から出力される正弦波信号の振幅に基づき、温度変化時のポジションセンサ５０の感度を計算し、該計算結果に基づき発光体駆動回路２１の入力レベルを補正するための制御信号を形成する計算手段、３５は、計算手段１７からの出力と入力端子３０側からの入力とを加算（または減算）して、発光体駆動回路２１への入力をポジションセンサ５０の温度変化分誤差を補正した入力とする第１の加算手段である。ポジションセンサ５０の発光体８は、該温度変化分誤差を補正した入力で駆動される。２６は、レンズシフト検出回路１８により形成される制御信号とトラッキング誤差検出回路７からの出力とを加算（または減算）し、トラッキング誤差検出回路７からの出力（トラッキング誤差信号）のオフセットを、上記レンズシフト検出出力で補正する第２の加算手段である。
【００１３】
上記構成において、情報の記録または再生時において、対物レンズ２のレンズシフトに基づき発生するトラッキング誤差信号のオフセットは、ポジションセンサ５０の発光体を駆動する発光体駆動回路への入力を計算手段１７からの出力で補正することで取除く。すなわち、温度変化分誤差を補正した正弦波信号がポジションセンサ５０から出力されるようにし、該出力に基づきレンズシフト検出回路１８でレンズシフト量を検出し対応した制御信号を形成する。該制御信号とトラッキング誤差信号とを第２の加算手段２６で加算（または減算）することで、トラッキング誤差信号のオフセットを補正する。オフセット補正されたトラッキング誤差信号はアクチュエータ駆動回路１４に入力され、アクチュエータ駆動回路１４はアクチュエータ１１を駆動して、対物レンズ２のトラッキング方向の変位を制御してトラッキング動作させる。
【００１４】
上記第３の実施例によっても、光ディスク装置において、ポジションセンサ５０の温度変化分誤差を補正した状態でトラッキング動作を行うことができるため、装置の使用環境や装置内で温度変化が発生した場合にも、正確なトラッキング動作が可能となる。また、光ピックアップの小型・軽量化や、生産性の向上、低コスト化なども図り易い。また、温度変化に基づくポジションセンサ５０の誤差も正確に検出することが可能となり、高精度のトラッキングが可能となる。
【００１５】
なお、上記第１の実施例では、図１では、乗算手段１５、記録手段１６、計算手段１７、レンズシフト検出回路１８、トラッキング誤差検出回路７、アクチュエータ駆動回路１４、第１の加算手段１９、第２の加算手段２０などを個別のブロックで図示したが、回路構成としては、これらを適宜組合わせて１つの回路または複数の回路としてもよい。同様に、上記第２の実施例でも、図２では、発光体駆動回路２１、正弦波発生回路２２、正弦波振幅検出回路２４、振幅記憶手段２５、計算手段１７、レンズシフト検出回路１８、トラッキング誤差検出回路７、アクチュエータ駆動回路１４、第１の加算手段１９、第２の加算手段２０などを個別のブロックで図示したが、これらのブロックを適宜組合わせて１つの回路または複数の回路とする回路構成としてもよい。さらに、上記第３の実施例でも、図３では、発光体駆動回路２１、正弦波発生回路２２、正弦波振幅検出回路２４、振幅記憶手段２５、計算手段１７、レンズシフト検出回路１８、トラッキング誤差検出回路７、アクチュエータ駆動回路１４、第１の加算手段３５、第２の加算手段２６などを個別のブロックで図示したが、これらのブロックを適宜組合わせて１つの回路または複数の回路とする回路構成としてもよい。
【００１６】
【発明の効果】
本発明によれば、光ディスク装置において、ポジションセンサの温度変化分誤差を補正した状態でトラッキング動作を行うことができるため、温度変化が発生した場合にも、この影響を抑えた正確なトラッキング動作が可能となる。
【図面の簡単な説明】
【図１】本発明の光ディスク装置の第１の実施例を示す図である。
【図２】本発明の光ディスク装置の第２の実施例を示す図である。
【図３】本発明の光ディスク装置の第３の実施例を示す図である。
【符号の説明】
１…光ディスク、２…対物レンズ、３…反射ミラー、４…レーザーダイオード、５、９…受光素子、６…レンズホルダ、７…トラッキング誤差検出回路、８…発光体、１０…反射板、１１…アクチュエータ、１２…温度センサ、１３…キャリッジ、１４…アクチュエータ駆動回路、１５…乗算手段、１６…記録手段、１７…計算手段、１８…レンズシフト検出回路、１９、３５…第１の加算手段、２０、２６…第２の加算手段、２１…発光体駆動回路、２２…正弦波発生回路、２３…正弦波信号加算手段、２４…正弦波振幅検出回路、２５…振幅記憶手段、５０…ポジションセンサ。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a tracking error signal offset correction technique in an optical disc device.
[0002]
[Prior art]
Conventional techniques related to the present invention include those described in, for example, JP-A-6-44587 (Patent Document 1) and JP-A-7-235064 (Patent Document 2). Japanese Patent Laying-Open No. 6-44587 describes a configuration in which the shift amount of an objective lens is detected and the offset of each error signal is corrected by a lens shift signal. As a technique for automatically correcting the position, the output of one photodetector of the position sensor and the output of the other photodetector are input to a subtractor, and when the objective lens is located at the neutral point, the position output from the subtractor A configuration is described in which the gain of the gain adjustment circuit is set so that the output of the sensor becomes zero.
[0003]
[Patent Document 1]
JP-A-6-44587 [Patent Document 2]
JP-A-7-235064
[Problems to be solved by the invention]
Among the above conventional techniques, in the technique described in JP-A-6-44587, when the sensitivity of the position sensor changes due to the temperature, the lens shift signal fluctuates, and the offset correction of each error signal may not be accurately performed. is there. Also in the technique described in Japanese Patent Application Laid-Open No. Hei 7-235064, if the sensitivities of the two photodetectors in the position sensor change with different temperature characteristics, there is a possibility that the offset correction of the output of the position sensor cannot be accurately performed.
An object of the present invention is to provide a lens shift amount detection output that compensates for a variation due to temperature from an position sensor even in a case where the temperature changes in an optical disk device in view of the situation of the related art described above. An object of the present invention is to enable an accurate tracking operation while suppressing the influence of the change.
An object of the present invention is to provide a technique capable of solving such a problem.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, according to the present invention, basically, as an optical disk device, a correction amount calculated based on an output of a temperature sensor for detecting a temperature or a temperature change of a position sensor by a lens shift detection output of a position sensor. Alternatively, the correction is performed by a correction amount calculated based on the amplitude of the lens shift amount detection output of the position sensor, and the offset correction of the tracking error signal is performed in a state where the error due to the temperature change of the position sensor is corrected.
Specifically, as an optical disk device,
(1) A position sensor (corresponding embodiment: reference numeral 50) for detecting displacement of the objective lens (corresponding embodiment: reference numeral 2) in the tracking direction, and a temperature sensor (corresponding embodiment) for detecting a temperature or a temperature change of the position sensor. : A first control signal corresponding to the lens shift amount with respect to the incident light beam of the objective lens is formed from the output of the position sensor and the position corresponding to a temperature change based on the output of the temperature sensor. A first correction means for calculating a correction amount of the output of the sensor, forming a second control signal corresponding to the calculation result, and correcting the first control signal by the second control signal; Embodiment: Reference numerals 15, 16, 17, 18, 19) and the offset of the tracking error signal based on the lens shift amount are compensated based on the output of the first correction means. Second correction means for: a structure having a (relevant Example code 20) and.
(2) A position sensor (corresponding embodiment: reference numeral 50) for detecting displacement of the objective lens (corresponding embodiment: reference numeral 2) in the tracking direction, and a lens shift amount with respect to an incident light beam of the objective lens from an output of the position sensor. Forming a corresponding first control signal, calculating a correction amount of the position sensor output corresponding to the temperature change based on the amplitude of the position sensor output, and forming a second control signal corresponding to the calculation result; A first correcting means for correcting the first control signal by a second control signal (applicable embodiment: reference numerals 22, 24, 25, 17, 18, and 19); and an output of the first correcting means. Second correction means (corresponding embodiment: reference numeral 20) for correcting an offset based on the lens shift amount of the tracking error signal is provided.
(3) A position sensor for detecting displacement of the objective lens in the tracking direction (applicable embodiment: reference numeral 50), a sensor drive circuit for driving the position sensor (applicable embodiment: reference numeral 21), and an output of the position sensor A lens shift detecting circuit (corresponding to reference numeral 18) for forming and outputting a first control signal corresponding to a lens shift amount with respect to the incident light beam of the objective lens, and responding to a temperature change based on the amplitude of the position sensor output. An arithmetic circuit (corresponding embodiments: reference numerals 24, 25 and 17) for calculating a correction amount of the position sensor output and forming and outputting a second control signal corresponding to the calculation result; A sensor input control means for controlling an input of the sensor drive circuit (corresponding embodiment: reference numeral 35); and a tracking error signal based on the first control signal. Of the lens shift amount offset correcting means for correcting an offset based on: a structure having a (relevant Example code 26) and.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a configuration example of an optical disc device as a first embodiment of the present invention. The first embodiment is an example in which the output of the position sensor is corrected based on the output of the temperature sensor.
In FIG. 1, 1 is an optical disk, 2 is an objective lens, 3 is a reflection mirror, 4 is a laser diode, 40 is a hologram element, 5 and 9 are light receiving elements, 6 is a lens holder, 7 is a tracking error detection circuit, and 8 is an LED. The light emitting body 10 and the like are fixed to the lens holder 6 and reflect the light from the light emitting body 8, and the reference numeral 11 is an actuator for driving the objective lens 2 via the lens holder 6. The luminous body 8 and the light receiving element 9 (strictly speaking, the luminous body 8, the light receiving element 9 and the reflection plate 10) constitute a position sensor 50 for detecting a displacement of the objective lens 2 in the tracking direction. The reflected light is reflected by the reflection plate 10, and the reflected light is received by the light receiving element 9 and converted into an electric signal. Reference numeral 12 denotes a temperature sensor for detecting the temperature or temperature change of the position sensor (a part including the light-emitting body 8 and the light-receiving element 9 or the light-emitting body 8 and the light-receiving element 9 and the reflection plate 10); 13 a carriage as a support; 14 is an actuator drive circuit for driving the actuator 11, 15 is a multiplication means for calculating a correction amount of the output of the position sensor 50 corresponding to the temperature change based on the output of the temperature sensor 12 and outputting it as a control signal optimized. 16 is a recording means for recording the voltage level of the neutral point of the position sensor 50 at the time of reference and at the time of temperature change, and 17 is for calculating the sensitivity of the position sensor 50 according to the temperature. Calculating means 18 for detecting the amount of lens shift with respect to the light beam incident on the objective lens 2 from the output of the position sensor 50 A lens shift detection circuit 19 for forming and outputting a control signal corresponding to this adds (or subtracts) the output from the multiplication means 15 and the output from the lens shift detection circuit 18, and outputs the control signal from the lens shift detection circuit 18. A first addition means 20 which makes the output of the position sensor 50 an output obtained by correcting the temperature change error, adds (or subtracts) the output of the first addition means and the output of the tracking error detection circuit 7. A second adder for making the output (tracking error signal) from the tracking error detection circuit 7 an output obtained by correcting the offset based on the lens shift. The first addition means obtains a lens shift detection output in which the temperature change error of the position sensor 50 is corrected, and the second addition means obtains a tracking error signal in which the offset based on the lens shift is corrected. .
[0007]
In the above configuration, at the time of recording or reproducing information, laser light emitted from the laser diode 4 in the optical pickup is reflected by the reflection mirror 3 and converged by the objective lens 2 to form an optical spot on the recording surface of the optical disc 1. Form. The objective lens 2 is driven by an actuator 11 and performs a predetermined tracking operation by a displacement in a tracking direction. At this time, an offset is generated in the tracking error signal for tracking control due to the lens shift with respect to the light beam incident on the objective lens 2. The offset of the tracking error signal based on the lens shift is corrected by correcting the output of the lens shift detection circuit 18 with the output from the multiplying means 15 and removing the corrected output. That is, the first control signal formed by the lens shift detection circuit 18 corresponding to the lens shift amount of the objective lens 2 is further converted to a second control signal obtained from the calculation result by the multiplication means 15 based on the output of the temperature sensor 12. By correcting using a signal, the output from the lens shift detection circuit 18 is used as an output obtained by correcting the temperature change error of the position sensor 50, and the output is used to correct the offset of the tracking error signal. The offset-corrected tracking error signal is input to the actuator drive circuit 14. The actuator drive circuit 14 drives the actuator 11 to control the displacement of the objective lens 2 in the tracking direction via the lens holder 6 to perform a tracking operation.
[0008]
According to the first embodiment, in the optical disk device, the tracking operation can be performed in a state where the temperature change error of the position sensor 50 is corrected, so that the temperature change occurs in the use environment of the device or in the device. In addition, an accurate tracking operation can be performed during a recording or reproducing operation.
[0009]
FIG. 2 is a diagram showing a configuration example of an optical disk device as a second embodiment of the present invention. The second embodiment is an example in which the output of the position sensor is corrected based on the change in the amplitude of the position sensor output corresponding to the temperature change.
In FIG. 2, reference numeral 2 denotes an objective lens, 7 denotes a tracking error detection circuit, 8 denotes a light-emitting element constituting a position sensor 50 for detecting displacement of the objective lens 2 in the tracking direction, and 9 denotes a light-receiving element similarly constituting the position sensor 50. , 11 is an actuator for driving the objective lens 2 via a lens holder (not shown), 14 is an actuator drive circuit for driving the actuator 11, 21 is a light emitter drive circuit for driving the light emitter 8, and 22 is a sine A sine wave generating circuit 23 for generating a wave signal; a sine wave signal adding means for adding a sine wave signal from the sine wave generating circuit 22 to an output of the light emitting element driving circuit 21; A lens shift amount with respect to an incident light beam of the lens 2 is detected, and a control signal corresponding thereto is formed and output. The circuit 24 is a sine wave amplitude detection circuit for detecting the amplitude of the sine wave signal from the output of the light receiving element 9, and the sine wave output from the sine wave amplitude detection circuit 24 is a reference time such as at normal temperature and a temperature change. The amplitude storage means 17 for storing a voltage level corresponding to the amplitude of the wave signal output calculates the sensitivity of the position sensor 50 due to the temperature based on the amplitude of the sine wave signal, and based on the calculation result, the lens shift detecting circuit 18 Calculation means 19 for forming a control signal for correcting the output adds (or subtracts) the output from the calculation means 17 and the output from the lens shift detection circuit 18 and outputs the output from the lens shift detection circuit 18 to the position sensor. The first adding means 20 which outputs the corrected temperature change error of 50, 20 adds the output of the first adding means and the output of the tracking error detection circuit 7 ( Other subtraction), and the output from the tracking error detecting circuit 7 (tracking error signal), a second adding means to output obtained by correcting an offset based on the lens shift. A lens shift detection output in which the temperature change error of the position sensor 50 is corrected is obtained from the first adder 19, and a tracking error signal in which the offset based on the lens shift is corrected is obtained from the second adder 20. can get.
[0010]
In the above configuration, similarly to the case of the first embodiment, at the time of recording or reproducing information, the laser light emitted from the laser diode (not shown) in the optical pickup (not shown) is converged by the objective lens 2. A light spot is formed on a recording surface on an optical disk (not shown). The objective lens 2 is driven by the actuator 11 and performs a predetermined tracking operation by displacement in the tracking direction. At this time, the offset of the tracking error signal generated based on the lens shift with respect to the incident light beam of the objective lens 2 is the lens shift. The output of the detection circuit 18 can be removed by correcting the output from the calculation means 17. That is, the first control signal formed by the lens shift detection circuit 18 corresponding to the lens shift amount of the objective lens 2 is further obtained from the calculation result by the calculation means 17 based on the output of the sine wave amplitude detection circuit 24. The correction from the control signal of No. 2 makes the output from the lens shift detection circuit 18 an output obtained by correcting the temperature change error of the position sensor 50, and the output corrects the offset of the tracking error signal. The offset-corrected tracking error signal is input to the actuator drive circuit 14, and the actuator drive circuit 14 drives the actuator 11 to control the displacement of the objective lens 2 in the tracking direction to perform the tracking operation.
[0011]
According to the second embodiment, in the optical disk device, the tracking operation can be performed in a state where the error of the temperature change of the position sensor 50 is corrected. Therefore, when the temperature change occurs in the use environment of the device or in the device. In addition, an accurate tracking operation can be performed during a recording or reproducing operation. In particular, in the configuration of the present embodiment, it is easy to reduce the size and weight of the optical pickup, improve the productivity, and reduce the cost. In addition, it is possible to more accurately detect an error of the position sensor 50 based on a temperature change, and additionally, it is possible to perform tracking with higher accuracy.
[0012]
FIG. 3 is a diagram showing a configuration example of an optical disc device as a third embodiment of the present invention. The third embodiment is an example in which the sensitivity of the position sensor at the time of temperature change is calculated based on the amplitude change of the position sensor output corresponding to the temperature change, and the calculation result is fed back to the position sensor drive side. is there.
In FIG. 3, reference numeral 2 denotes an objective lens, 7 denotes a tracking error detection circuit, 8 denotes a light-emitting element that forms the position sensor 50, 9 denotes a light-receiving element that also forms the position sensor 50, and 11 denotes an actuator that drives the objective lens 2. , 14 is an actuator driving circuit for driving the actuator 11, 21 is a luminous body driving circuit for driving the luminous body 8, 22 is a sine wave generating circuit for generating a sine wave signal, and 23 is an output of the luminous body driving circuit 21. , A sine wave signal adding means for adding a sine wave signal from the sine wave generation circuit 22 to the output of the position sensor 50 to detect a lens shift amount with respect to an incident light beam of the objective lens 2, and to output a control signal corresponding thereto. A lens shift detection circuit 24 for forming and outputting a sine wave amplitude detection circuit for detecting the amplitude of the sine wave signal from the output of the light receiving element 9. , 25 are amplitude storage means for storing the voltage level corresponding to the amplitude of the sine wave signal output from the sine wave amplitude detection circuit 24 at the time of a reference time such as at normal temperature and at the time of temperature change. Calculation for calculating the sensitivity of the position sensor 50 at the time of temperature change based on the amplitude of the sine wave signal output from the circuit, and forming a control signal for correcting the input level of the light emitter driving circuit 21 based on the calculation result. The means 35 adds (or subtracts) the output from the calculating means 17 and the input from the input terminal 30, and inputs the input to the light emitter driving circuit 21 with the temperature change error of the position sensor 50 corrected. This is a first adding means. The luminous body 8 of the position sensor 50 is driven by an input in which the temperature change error has been corrected. 26 adds (or subtracts) the control signal formed by the lens shift detection circuit 18 and the output from the tracking error detection circuit 7, and sets the offset of the output (tracking error signal) from the tracking error detection circuit 7 to This is a second adding means for correcting with a lens shift detection output.
[0013]
In the above configuration, when recording or reproducing information, the offset of the tracking error signal generated based on the lens shift of the objective lens 2 is obtained by calculating the input to the illuminant driving circuit for driving the illuminant of the position sensor 50 from the calculating means 17. Removed by correcting with the output of. That is, a sine wave signal in which a temperature change error has been corrected is output from the position sensor 50, and based on the output, the lens shift detection circuit 18 detects a lens shift amount and forms a corresponding control signal. The control signal and the tracking error signal are added (or subtracted) by the second adding means 26 to correct the offset of the tracking error signal. The offset-corrected tracking error signal is input to the actuator drive circuit 14, and the actuator drive circuit 14 drives the actuator 11 to control the displacement of the objective lens 2 in the tracking direction to perform the tracking operation.
[0014]
According to the third embodiment as well, the tracking operation can be performed in the optical disk device in a state where the temperature change error of the position sensor 50 is corrected, so that the temperature change occurs in the use environment of the device or in the device. Also, an accurate tracking operation can be performed. Further, it is easy to reduce the size and weight of the optical pickup, improve productivity, and reduce costs. Further, it is possible to accurately detect an error of the position sensor 50 due to a temperature change, and it is possible to perform highly accurate tracking.
[0015]
In the first embodiment, in FIG. 1, the multiplying means 15, the recording means 16, the calculating means 17, the lens shift detecting circuit 18, the tracking error detecting circuit 7, the actuator driving circuit 14, the first adding means 19, Although the second adding means 20 and the like are illustrated as individual blocks, the circuit configuration may be a single circuit or a plurality of circuits by appropriately combining them. Similarly, also in the second embodiment, in FIG. 2, the luminous body drive circuit 21, the sine wave generation circuit 22, the sine wave amplitude detection circuit 24, the amplitude storage means 25, the calculation means 17, the lens shift detection circuit 18, the tracking Although the error detection circuit 7, the actuator drive circuit 14, the first addition means 19, the second addition means 20, and the like are illustrated as individual blocks, these blocks are appropriately combined to form one circuit or a plurality of circuits. A circuit configuration may be used. Further, also in the third embodiment, in FIG. 3, the luminous body drive circuit 21, the sine wave generation circuit 22, the sine wave amplitude detection circuit 24, the amplitude storage means 25, the calculation means 17, the lens shift detection circuit 18, the tracking error Although the detection circuit 7, the actuator drive circuit 14, the first addition means 35, the second addition means 26, and the like are illustrated as individual blocks, these circuits are appropriately combined to form one circuit or a plurality of circuits. It may be configured.
[0016]
【The invention's effect】
According to the present invention, in the optical disk device, the tracking operation can be performed in a state where the error due to the temperature change of the position sensor is corrected. Therefore, even when a temperature change occurs, an accurate tracking operation in which this effect is suppressed can be performed. It becomes possible.
[Brief description of the drawings]
FIG. 1 is a diagram showing a first embodiment of an optical disk device of the present invention.
FIG. 2 is a diagram showing a second embodiment of the optical disk device of the present invention.
FIG. 3 is a diagram showing a third embodiment of the optical disk device of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Optical disk, 2 ... Objective lens, 3 ... Reflection mirror, 4 ... Laser diode, 5, 9 ... Light receiving element, 6 ... Lens holder, 7 ... Tracking error detection circuit, 8 ... Light emitting body, 10 ... Reflector, 11 ... Actuator, 12: Temperature sensor, 13: Carriage, 14: Actuator drive circuit, 15: Multiplication means, 16: Recording means, 17: Calculation means, 18: Lens shift detection circuit, 19, 35: First addition means, 20 , 26: second adding means, 21: light emitting element driving circuit, 22: sine wave generating circuit, 23: sine wave signal adding means, 24: sine wave amplitude detecting circuit, 25: amplitude storing means, 50: position sensor.

Claims

In an optical disc device that performs tracking on the recording surface of an optical disc by displacement of an objective lens, and performs one or both of information recording and reproduction,
A position sensor for detecting a displacement of the objective lens in the tracking direction,
A temperature sensor for detecting the temperature or temperature change of the position sensor,
A first control signal corresponding to a lens shift amount with respect to an incident light beam of the objective lens is formed from an output of the position sensor, and a correction amount of an output of the position sensor corresponding to a temperature change based on an output of the temperature sensor. Calculating a second control signal corresponding to the calculation result, and correcting the first control signal with the second control signal;
A second correction unit for correcting an offset based on the lens shift amount of the tracking error signal based on an output of the first correction unit;
An optical disk device, characterized in that the optical disk device is configured to control the drive of the objective lens based on the output of the second correction means to perform tracking.

In an optical disc device that performs tracking on the recording surface of an optical disc by displacement of an objective lens, and performs one or both of information recording and reproduction,
A position sensor for detecting a displacement of the objective lens in the tracking direction,
A temperature sensor for detecting the temperature or temperature change of the position sensor,
A lens displacement detection circuit that forms and outputs a first control signal corresponding to a lens shift amount with respect to a light beam incident on the objective lens from an output of the position sensor;
An arithmetic circuit for calculating a correction amount of a position sensor output corresponding to a temperature change of the position sensor based on an output of the temperature sensor, forming and outputting a second control signal corresponding to the calculation result,
Control signal correction means for adding or subtracting the first control signal and the second control signal from each other, and correcting the first control signal with the second control signal;
A tracking error detection circuit that detects a tracking error and outputs a tracking error signal based on reflected light from the optical disk obtained through the objective lens;
Offset correction means for adding or subtracting the output of the control signal correction means and the tracking error signal to each other, and correcting an offset based on the lens shift amount of the tracking error signal;
Lens drive control means for controlling the drive of the objective lens based on the output of the offset correction means,
An optical disk device, comprising: performing offset correction of the tracking error signal in a state where an error corresponding to a temperature change of the position sensor is corrected, and performing tracking by controlling the objective lens.

In an optical disc device that performs tracking on the recording surface of an optical disc by displacement of an objective lens, and performs one or both of information recording and reproduction,
A position sensor for detecting a displacement of the objective lens in the tracking direction,
A first control signal corresponding to a lens shift amount with respect to an incident light beam of the objective lens is formed from an output of the position sensor, and a correction amount of the position sensor output corresponding to a temperature change is calculated based on an amplitude of the position sensor output. First correction means for forming a second control signal corresponding to the calculation result, and correcting the first control signal with the second control signal;
A second correction unit for correcting an offset of the tracking error signal based on the lens shift amount based on an output of the first correction unit;
An optical disk device, characterized in that the optical disk device is configured to control the drive of the objective lens based on the output of the second correction means to perform tracking.

In an optical disc device that performs tracking on the recording surface of an optical disc by displacement of an objective lens, and performs one or both of information recording and reproduction,
A position sensor for detecting a displacement of the objective lens in the tracking direction,
A sensor drive circuit for driving the position sensor;
A lens displacement detection circuit that forms and outputs a first control signal corresponding to a lens shift amount with respect to a light beam incident on the objective lens from an output of the position sensor;
The amplitude of the output of the position sensor is detected, a correction amount of the position sensor output corresponding to the temperature change of the position sensor is calculated based on the detection result, and a second control signal corresponding to the calculation result is formed and output. An arithmetic circuit that performs
Control signal correction means for adding or subtracting the first control signal and the second control signal from each other, and correcting the first control signal with the second control signal;
A tracking error detection circuit that detects a tracking error and outputs a tracking error signal based on reflected light from the optical disk obtained through the objective lens;
Offset correction means for adding or subtracting the output of the control signal correction means and the tracking error signal to each other, and correcting an offset based on the lens shift amount of the tracking error signal;
Lens control means for controlling the driving of the objective lens based on the output of the offset correction means,
An optical disk device, comprising: performing offset correction of the tracking error signal in a state where an error corresponding to a temperature change of the position sensor is corrected, and performing tracking by controlling the objective lens.

In an optical disc device that performs tracking on the recording surface of an optical disc by displacement of an objective lens, and performs one or both of information recording and reproduction,
A position sensor for detecting a displacement of the objective lens in the tracking direction,
A sensor drive circuit for driving the position sensor;
A lens shift detection circuit that forms and outputs a first control signal corresponding to a lens shift amount with respect to a light beam incident on the objective lens from an output of the position sensor;
An arithmetic circuit for calculating a correction amount of the position sensor output corresponding to the temperature change based on the amplitude of the position sensor output, and forming and outputting a second control signal corresponding to the calculation result;
Sensor input control means for controlling the input of the sensor drive circuit by the second control signal;
Offset correction means for correcting an offset based on the lens shift amount of the tracking error signal by the first control signal;
Controlling the position sensor output in response to a temperature change by the second control signal, forming the first control signal based on the controlled position sensor output, and using the first control signal An optical disc device, wherein the offset of the tracking error signal is corrected, and tracking is performed by controlling the driving of the objective lens based on the offset-corrected tracking error signal.

6. The optical disk device according to claim 2, wherein the arithmetic circuit is configured to calculate a correction amount of the position sensor output based on the stored position sensor output with respect to a temperature change.

6. The optical disk according to claim 3, wherein the position sensor is driven by a sine wave input and outputs a sine wave signal, and the arithmetic circuit detects an amplitude of the output sine wave signal. apparatus.