JP2004013950A - Optical disk device and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical disk device capable of achieving trace control not influenced by a damage, a defect, decentering or the like on a disk to prevent the occurrence of lens offset which adversely affects R/W characteristics regarding an optical disk device for performing trace control by using a stepping motor. <P>SOLUTION: The number of tracks covered within predetermined time is calculated from the lapse of time information on a disk such as an ATIP (Absolute Time In Pregroove) to be obtained during tracking, and the moving distance of a lens is calculated by multiplying this by a track pitch. A stepping motor is driven to feed a traverse by an amount equal to the calculated distance, and a pickup is accordingly moved. <P>COPYRIGHT: (C)2004,JPO

Description

【００４１】
計算式（１）を解いて、下記の計算式（２）が求められる。
【００４２】
【数２】

【００４３】
従ってアドレス３０５（測定開始アドレス）からアドレス３０６（測定終了アドレス）までのトラック横断本数Ｔ^＊＊（位置３０６−位置３０５）は、計算式（２）から、Ｔ^＊＊（位置３０６）−Ｔ^＊＊（位置３０５）で求めることが出来る。さらにこの結果にトラックピッチＰを乗ずれば、アドレス３０５（測定開始アドレス）からアドレス３０６（測定終了アドレス）までの半径方向の距離（光ビームスポットの移動距離。トラバースモータ１１０によって光ピックアップ１０２を移動させる距離）が算出出来る。
【００４４】
図２は、本発明の実施例１の光ディスク装置の制御方法（再生時（トラッキング制御時）のトラバースモータの制御方法）を示すフローチャートである。
再生時、まず判定部１２１は、タイマを起動し（ステップ２０１）、タイマ値に０（初期値）を設定する（タイマ動作継続）（ステップ２０２）。演算部１２２は、位置情報検出部１１４が出力した現在の位置情報Ｐ（ｉ）を検出する（ステップ２０３）。
トラッキングアクチュエータが対物レンズを動かして、光ビームスポットがトラックの中心に位置するように制御する（この制御は常に実行する。）。光ビームスポットの位置が光ディスクの外周に移って行くに従い、対物レンズがハウジングの中心から次第にずれてくる。判定部１２１が、所定の時間経過したか否かをチェックする（ステップ２０４）。所定の時間経過するまでこの処理を繰り返す。
【００４５】
所定の時間経過したら、判定部１２１はタイマ値を０（初期値）に戻す（タイマ動作継続）（ステップ２０５）。演算部１２２は、ｉに１を加算し（ステップ２０６）、位置情報検出部１１４が出力した所定時間経過後の位置情報Ｐ（ｉ）を検出する（ステップ２０７）。演算部１２２は、位置情報Ｐ（ｉ−１）、Ｐ（ｉ）より移動量を算出する（ステップ２０８）。この時、演算部１２２は後述する補正値を加算する。演算部１２２で算出された移動量は、制御部１１７からトラバースモータ駆動部１０８に伝送される。トラバースモータ駆動部１０８は、伝送された移動量分トラバースモータを駆動する（ステップ２０９）。
トラバースモータ駆動終了時には、計算上対物レンズはハウジングの中心にくるはずであるが、実際には時間のずれ、光ディスクのトラックピッチのずれ等の理由により難しい。そのため補正を行う。まず制御部１１７は、トラバースモータ駆動停止時のトラッキングアクチュエータ駆動部１０７が出力するトラッキングエラーの値を検出する（ステップ２１０）。演算部１２２は、トラッキングエラーの絶対値が閾値より大きいか否かをチェックする（ステップ２１１）。トラッキングエラーの絶対値が大きくなる程、対物レンズがハウジングの中心からずれる。閾値より大きい場合は、演算部１２２は、補正値を算出し、次回の移動量算出時（ステップ２０８）に移動量を補正するため、算出した補正値を記憶する（ステップ２１２）。また閾値より小さい場合は、演算部１２２は、補正値に０を設定する（ステップ２１３）。ステップ２０４に戻り処理を繰り返す。
【００４６】
本発明によれば、光ディスクに傷等があっても、記録又は再生時（トラッキング制御時）に対物レンズがハウジング内で偏ること無く、トラッキング制御を行うことが可能となる。
図４を用いて具体的に説明する。図４は本発明の実施例１の光ディスク装置で傷を有する光ディスクを再生した時（トラッキング制御時）のトラッキング制御量の変化（実線４０２）及び光ピックアップ１０２内での対物レンズの位置のずれを示す図である。比較のため、従来例でのトラッキング制御量の変化を破線４０３、４０４で示す。４０１は従来例における閾値（トラッキングオフセット判定レベル）である。４２１、４２２、４２３は、光ピックアップ内での対物レンズの位置を示す。
期間４１１〜４１２において光ディスク装置は、トラバースモータ１１０を停止させたまま、トラッキングアクチュエータを駆動して対物レンズを動かして、光ビームスポットを記録トラックに追従させる。同時に光ディスク装置は、所定時間毎に光ディスク１０１上の時間情報の変化から光ビームスポットが移動したトラック本数を算出する。所定時間毎に（４１２の位置）、光ディスク装置はトラバースモータ１１０を駆動してフィード１０９を動かし、対物レンズをハウジングの中央に戻す（４１２〜４１３）。対物レンズがハウジングの中央に戻ったら（４１３）、トラバースモータ１１０の駆動を終了する。これにより、安定した記録再生特性を得ることが出来る。
【００４７】
従来例の光ディスク装置においては、トラッキング制御量が閾値（トラッキングオフセット判定レベル）に達した後、一定期間が経過するまで判定部はトラバースモータの起動を決定することが出来なかった。そのため、実線４０３に示すような応答の遅れが生じた。光ディスクの傷がある部分ではトラッキングエラーの値が大きく変動する故、判定部がトラバースモータの起動を決定するタイミングは更に遅れ、実線４０４に示すような応答を生じた。
本発明の光ディスク装置においては、実線４０３のような応答の遅れが生ぜず、光ディスクに傷があってもその影響を受けない。
【００４８】
《実施例２》
図１、図５を用いて、本発明の実施例２の光ディスク装置について説明する。実施例２の光ディスクはＣＤ−ＲＯＭ（コンパクト光ディスク）である（従来例に記載した様に、他の任意の光ディスクであっても良い。）。上記ＣＤ−ＲＯＭにおいては、線速度が一定で、光ディスク上の再生位置によって回転速度が変化するＣＬＶ方式で情報を再生する。
【００４９】
光ディスクの構造については、図３で説明済みである。
次に、実施例２の光ディスク装置の構成について説明する。図１は本発明の実施例２の光ディスク装置の構成を示すブロック図である。図１については、実施例１で説明済みである。実施例２においては、判定部１２１及び演算部１２２の動作が実施例１と異なる。それ以外の点で、実施例２は実施例１と同一である。
【００５０】
実施例２においては、再生時（トラッキング制御時）に光ビームスポットが光ディスクの半径方向に所定距離を移動する毎に、トラバースモータを駆動する。実施例２の演算部１２２は、判定部１２１がトラバースモータの起動を指示する毎に、位置情報検出部１１６が出力する位置情報を入力し、記憶する。実施例２の演算部１２２は、前回のトラバースモータの起動指令入力時の光ビームスポットの位置から所定距離（閾値）だけ移動した位置のアドレス（次にトラバースモータを起動する目標位置）を算出する。その演算方法は実施例１と同様である（未知数はＴ＊＊でなく、Ａ＊＊になる。）。この時、実施例１で説明した補正値を加算することが好ましい。
【００５１】
実施例２の判定部１２１は、光ビームスポットが光ディスクの半径方向に移動した距離が所定の閾値以上か否か（光ビームスポットのアドレスが、演算部１２２が算出した目標アドレスより大きな値か否か）を判定する。移動距離が所定の閾値以上であれば、判定部１２１はトラバースモータの起動を指示する。制御部１１８は、トラバースモータ駆動部１０８に指令を送って、演算部１２２が計算した距離だけトラバースモータ１１０を駆動させる。これにより、対物レンズはハウジング内の中心近傍に戻る。
実施例２においては、ＣＬＶ方式の光ディスクの内周から外周まで、１回のトラバースモータ１１０の駆動量がほぼ一定になるという特徴を有する（実施例１の光ディスク装置においては、光ディスクの内周では１回のトラバースモータ１１０の駆動量は大きく、外周に移動するに従って小さくなる。）。ＣＡＶ方式の光ディスクについては、実施例２の光ディスク装置は実施例１と同様の動作をする。
【００５２】
図５は、本発明の実施例２の光ディスク装置の制御方法（再生時（トラッキング制御時）のトラバースモータの制御方法）を示すフローチャートである。
再生時、まず演算部１２２は、位置情報検出部１１４が出力した現在の位置情報Ｐ（ｉ）（起点の位置情報）を検出し、記憶する（ステップ５０１）。さらに演算部１２２は、位置情報検出部１１４が出力した新たな現在の位置情報Ｐ（ｊ）を検出する（ステップ５０２）。演算部１２２は、位置情報Ｐ（ｊ）、Ｐ（ｉ）の差が閾値より大きいか否かをチェックする（ステップ５０３）。位置情報Ｐ（ｊ）、Ｐ（ｉ）の差が閾値より小さい間は、ステップ５０２に戻り処理を繰り返す。
位置情報Ｐ（ｊ）、Ｐ（ｉ）の差が閾値以上になれば、演算部１２２は、位置情報Ｐ（ｉ）、Ｐ（ｊ）より移動量を算出する（ステップ５０４）。この時、演算部１２２は後述する補正値を加算する。演算部１２２で算出された移動量は、制御部１１７からトラバースモータ駆動部１０８に伝送される。トラバースモータ駆動部１０８は、伝送された移動量分トラバースモータを駆動する（ステップ５０５）。演算部１２２は、位置情報Ｐ（ｉ）に位置情報Ｐ（ｊ）を設定する（ステップ５０６）。
【００５３】
トラバースモータ駆動終了時には、計算上対物レンズはハウジングの中心にくるはずであるが、実際には時間のずれ、光ディスクのトラックピッチのずれ等の理由により難しい。そのため補正を行う。まず制御部１１７は、トラバースモータ駆動停止時のトラッキングアクチュエータ駆動部１０７が出力するトラッキングアクチュエータの駆動量を検出する（ステップ５０７）。演算部１２２は、トラッキングアクチュエータの駆動量が閾値より大きいか否かをチェックする（ステップ５０８）。トラッキングアクチュエータの駆動量が大きくなる程、対物レンズがハウジングの中心からずれる。閾値より大きい場合は、演算部１２２は、補正値を算出し、次回の移動量算出時（ステップ５０４）に移動量を補正するため、算出した補正値を記憶する（ステップ５０９）。また閾値より小さい場合は、演算部１２２は、補正値に０を設定する（ステップ５１０）。ステップ５０２に戻り処理を繰り返す。
【００５４】
実施例２の光ディスク装置及びその制御方法は、実施例１と同様の効果を有する。光ディスクに傷があっても、トラバースモータの制御がその傷の影響を受けることはない。
本実施例においては、トラック３０２に光ピックアップ１０２を追従させ、光ビームスポットの半径方向の移動距離が所定の本数に達した時に、光ディスク装置はトラバースモータ１１０を駆動する。例えばこの所定の本数を１０本に設定することにより、対物レンズはハウジング内でトラック本数１０本分以上偏ることが無く、より安定したトラッキング制御を行うことが可能となる。
【００５５】
《実施例３》
図６〜図９を用いて、本発明の実施例３の光ディスク装置について説明する。実施例３の光ディスクはＣＤ−ＲＯＭ（コンパクト光ディスク）である（従来例に記載した様に、他の任意の光ディスクであっても良い。）。上記ＣＤ−ＲＯＭにおいては、線速度が一定で、光ディスク上の再生位置によって回転速度が変化するＣＬＶ方式で情報を再生する。
【００５６】
光ディスクの構造については、図３で説明済みである。
次に、実施例３の光ディスク装置の構成について説明する。図６は本発明の実施例３の光ディスク装置の構成を示すブロック図である。実施例３の光ディスク装置（図６）は、実施例１の光ディスク装置（図１）と類似の構成を有する。図６において、実施例１（図１）と同一のブロックには同一の符号を付している。実施例１と同一のブロックの説明を省略する。
実施例１（図１）においては、制御部１１８は判定部１２１、演算部１２２を有した。これに代えて、実施例３（図６）の制御部１１８は判定部１２１、演算部６２２を有する。それ以外の点において、実施例３（図６）は実施例１（図１）と同一である。
【００５７】
判定部１２１は、タイマ（時間計測部）を有する。記録又は再生時（トラッキング制御時）、判定部１２１は、所定時間が経過したか否かを判定し、所定時間毎にトラバースモータの起動を指示する。光ディスクの最内周においても、所定時間にハウジング内で対物レンズが変位した量が、良い記録再生特性を発揮できる範囲内に収まる様に、所定時間を決定する。
演算部６２２は、判定部１２１がトラバースモータの起動を指示する毎に（所定時間毎に）、回転情報検出部１０４が出力するスピンドルモータ１０３の回転情報を入力し、記憶する。演算部６２２は、前回のトラバースモータの起動指令入力時から今回のトラバースモータの起動指令入力時までの期間のスピンドルモータ１０３の回転数（回転情報である回転パルスのカウント値）から、光ビームスポットが光ディスクの半径方向に移動した距離を計算する。この時、実施例１で詳述した補正値を加算することが好ましい。制御部１１８は、トラバースモータ駆動部１０８に指令を送って、演算部６２２が計算した距離だけトラバースモータ１１０を駆動させる。これにより、対物レンズはハウジング内の中心近傍に戻る。
【００５８】
図８は本発明の実施例３の光ディスク装置のＦＧ波形を示す図である。図８において、スピンドルモータ１０３に回転情報検出部１０４としてＦＧ（Ｆｒｅｑｕｅｎｃｙ　Ｇｅｎｅｒａｔｏｒ）パルス発生器が搭載されている。回転情報検出部１０４は、光ディスクの回転に応じたＦＧパルスを出力する。ＦＧパルスの数をカウントすることによりスピンドルモータの回転角度を検出することが出来、一定時間内に発生するＦＧパルスの数をカウントすることによりスピンドルモータの回転数を検出することが出来る。
【００５９】
演算部６２２が、再生時における所定時間毎の光ビームスポットの半径方向の移動距離（光ピックアップ１０２の移動距離）を算出する方法について説明する。ビームスポットが光ディスク１０１上でアドレス３０５（測定開始アドレス。図３）の位置にあるとして、所定時間後アドレス３０６（測定終了アドレス）の位置に来たとすると、下記の計算式（３）が成り立つ。ここで、ＦＧは所定時間内でのＦＧパルス数、ｎは１回転中のＦＧパルス数、Ｐはトラックピッチ（ｍｍ）である
Ｌ＝（ＦＧ／ｎ）・Ｐ　　　　　　　　　・・・（３）
【００６０】
所定時間内のＦＧ波形８０１のパルス数８０２（ＦＧ）を測定しておいて、これを１回転中のＦＧ波形８０１のパルス数８０３（ｎ）で割ることにより、所定時間内でのスピンドルモータ１０３の回転数（ＦＧ／ｎ）を求めることが出来る。スピンドルモータ１０３が１回転すれば、トラック３０２に追従している光ピックアップ１０２は、１トラック移動するので、上述の回転数にトラックピッチＰを乗ずれば、所定時間内での光ビームスポットの移動距離（トラバースモータ１１０によって光ピックアップ１０２を移動させる距離）Ｌが算出出来る。
【００６１】
実施例３の演算部６２２は、カウンタとマイクロコンピュータ（ＣＰＵを有する。）である制御部１１８によって実行されるプログラムとを有する。カウンタは、ＦＧパルスを入力し、カウントアップする２進カウンタである。判定部１２１（マイクロコンピュータである制御部１１８によって実行されるプログラムである。）がトラバースモータの起動を指示すると、演算部６２２（マイクロコンピュータで実行されるプログラム）は、その時のカウンタ値を入力し、記憶する。又演算部６２２は、前回のトラバースモータの起動指令時のカウンタ値と、今回のカウンタ値との差分を計算して、光ビームスポットの移動距離を算出する。
【００６２】
これに代えて、実施例３の演算部６２２は、外部割込み端子を有するマイクロコンピュータ（ＣＰＵを有する。）である制御部１１８によって実行されるプログラムであっても良い。
外部割込み端子には、ＦＧパルスが入力される。外部割込みがあると、マイクロコンピュータ（制御部１１８）は、ＦＧパルスをカウントし、記憶する２進カウンタプログラム（割り込みプログラム）を実行する。判定部１２１（マイクロコンピュータである制御部１１８によって実行されるプログラムである。）がトラバースモータの起動を指示すると、演算部６２２（マイクロコンピュータで実行されるプログラム）は、その時のカウンタ値（割り込みプログラムでカウントした値）を読み出し、記憶する。又演算部６２２は、前回のトラバースモータの起動指令時のカウンタ値と、今回のカウンタ値との差分を計算して、光ビームスポットの移動距離を算出する。
【００６３】
図７は、本発明の実施例３の光ディスク装置の制御方法（再生時（トラッキング制御時）のトラバースモータの制御方法）を示すフローチャートである。
再生時、まず判定部１２１は、タイマを起動し（ステップ７０１）、回転情報検出部１０４は、スピンドルモータの回転パルスのカウンタを起動する（ステップ７０２）。判定部１２１は、タイマ値に０（初期値）を設定する（タイマ動作継続）（ステップ７０３）。演算部６２２は、回転情報検出部１０４が出力した現在のカウント値Ｒ（ｉ）を検出する（ステップ７０４）。
トラッキングアクチュエータが対物レンズを動かして、光ビームスポットがトラックの中心に位置するように制御する（この制御は常に実行する。）。光ビームスポットの位置が光ディスクの外周に移って行くに従い、対物レンズがハウジングの中心から次第にずれてくる。判定部１２１が、所定の時間経過したか否かをチェックする（ステップ７０５）。所定の時間経過するまでこの処理を繰り返す。
【００６４】
所定の時間経過したら、判定部１２１はタイマ値を０（初期値）に戻す（タイマ動作継続）（ステップ７０６）。演算部６２２は、ｉに１を加算し（ステップ７０７）、回転情報検出部１０４が出力した所定時間経過後のカウント値Ｒ（ｉ）を検出する（ステップ７０８）。演算部６２２は、カウント値Ｒ（ｉ−１）、Ｒ（ｉ）より移動量を算出する（ステップ７０９）。この時、演算部６２２は後述する補正値を加算する。演算部６２２で算出された移動量は、制御部１１７からトラバースモータ駆動部１０８に伝送される。トラバースモータ駆動部１０８は、伝送された移動量分トラバースモータを駆動する（ステップ７１０）。
トラバースモータ駆動終了時には、計算上対物レンズはハウジングの中心にくるはずであるが、実際には時間のずれ、光ディスクのトラックピッチのずれ等の理由により難しい。そのため補正を行う。まず制御部１１７は、トラバースモータ駆動停止時のトラッキングアクチュエータ駆動部１０７が出力するトラッキングエラーの値を検出する（ステップ７１１）。トラッキングエラーの絶対値が大きくなる程、対物レンズがハウジングの中心からずれる。演算部６２２は、補正値を算出し、次回の移動量算出時（ステップ７０９）に移動量を補正するため、算出した補正値を記憶する（ステップ７１２）。ステップ７０５に戻り処理を繰り返す。
【００６５】
本発明によれば、光ディスクに傷等があっても、記録又は再生時（トラッキング制御時）に対物レンズがハウジング内で偏ること無く、トラッキング制御を行うことが可能となる。
図９を用いて具体的に説明する。図９は本発明の実施例３の光ディスク装置で傷を有する光ディスクを再生した時（トラッキング制御時）のトラッキング制御量の変化（実線９０２）及び光ピックアップ１０２内での対物レンズの位置のずれを示す図である。比較のため、従来例でのトラッキング制御量の変化を破線９０３、９０４で示す。９０１は従来例における閾値（トラッキングオフセット判定レベル）である。９２１、９２２、９２３は、光ピックアップ内での対物レンズの位置を示す。
期間９１１〜９１２において光ディスク装置は、トラバースモータ１１０を停止させたまま、トラッキングアクチュエータを駆動して対物レンズを動かして、光ビームスポットを記録トラックに追従させる。同時に演算部６２２は、スピンドルモータ１０３に搭載された回転情報検出部１０４により検出されたＦＧパルスの数をカウントしながら、所定時間毎に、所定時間内に光ビームスポットが移動したトラック本数を算出する。所定時間毎に（９１２の位置）、光ディスク装置はトラバースモータ１１０を駆動してフィード１０９を動かし、対物レンズをハウジングの中央に戻す（９１２〜９１３）。対物レンズがハウジングの中央に戻ったら（９１３）、トラバースモータ１１０の駆動を終了する。これにより、安定した記録再生特性を得ることが出来る。
【００６６】
従来例の光ディスク装置においては、トラッキング制御量が閾値（トラッキングオフセット判定レベル）に達した後、一定期間が経過するまで判定部はトラバースモータの起動を決定することが出来なかった。そのため、破線９０３に示すような応答の遅れが生じた。光ディスクの傷がある部分ではトラッキングエラーの値が大きく変動する故、判定部がトラバースモータの起動を決定するタイミングは更に遅れ、破線９０４に示すような応答を生じた。
本発明の光ディスク装置においては、破線９０３のような応答の遅れが生ぜず、光ディスクに傷があってもその影響を受けない。
【００６７】
《実施例４》
図６、図１０を用いて、本発明の実施例４の光ディスク装置について説明する。実施例４の光ディスクはＣＤ−ＲＯＭ（コンパクト光ディスク）である（従来例に記載した様に、他の任意の光ディスクであっても良い。）。上記ＣＤ−ＲＯＭにおいては、線速度が一定で、光ディスク上の再生位置によって回転速度が変化するＣＬＶ方式で情報を再生する。
【００６８】
光ディスクの構造については、図３で説明済みである。
次に、実施例４の光ディスク装置の構成について説明する。図６は本発明の実施例４の光ディスク装置の構成を示すブロック図である。図６については、実施例３で説明済みである。実施例４においては、判定部１２１及び演算部６２２の動作が実施例３と異なる。それ以外の点で、実施例４は実施例３と同一である。
【００６９】
実施例４においては、再生時（トラッキング制御時）にスピンドルモータが所定回転数だけ回転する毎に、トラバースモータを駆動する。
実施例４の演算部６２２は、判定部１２１がトラバースモータの起動を指示する毎に、回転情報検出部１０４が出力するＦＧパルスのカウント値を読み込み、記憶する。実施例４の演算部６２２は、前回のトラバースモータの起動指令入力時のＦＧパルスのカウント値から所定値（閾値）だけ大きな値の目標カウント値を算出する。その演算方法は実施例３と同様である（式（３））。この時、実施例１で説明した補正値を加算することが好ましい。
実施例４の演算部６２２の構成は、実施例３と同様であって良い。
【００７０】
実施例４の判定部１２１は、前回トラバースモータを駆動した時から現在までのカウント値の変化が所定の閾値以上か否か（現在のカウント値が、目標カウント値より大きな値か否か）を判定する。ＦＧパルスのカウント値の変化が所定の閾値以上であれば、判定部１２１はトラバースモータの起動を指示する。制御部１１８は、トラバースモータ駆動部１０８に指令を送って、演算部６２２が計算した距離だけトラバースモータ１１０を駆動させる。これにより、対物レンズはハウジング内の中心近傍に戻る。
実施例３、４においては、ＣＡＶ方式、ＣＬＶ方式等の光ディスクの内周から外周まで、１回のトラバースモータ１１０の駆動量がほぼ一定になる。
【００７１】
図１０は、本発明の実施例４の光ディスク装置の制御方法（再生時（トラッキング制御時）のトラバースモータの制御方法）を示すフローチャートである。
再生時、まず回転情報検出部１０４は、スピンドルモータの回転パルスのカウンタを起動する（ステップ１００１）。演算部６２２は、回転情報検出部１０４が出力した現在のカウント値Ｒ（ｉ）（起点のカウント値）を検出し、記憶する（ステップ１００２）。さらに演算部６２２は、回転情報検出部１０４が出力した新たな現在のカウント値Ｒ（ｊ）を検出する（ステップ１００３）。演算部６２２は、カウント値Ｒ（ｊ）、Ｒ（ｉ）の差が閾値より大きいか否かをチェックする（ステップ１００４）。カウント値Ｒ（ｊ）、Ｒ（ｉ）の差が閾値より小さい間は、ステップ１００３に戻り処理を繰り返す。
カウント値Ｒ（ｊ）、Ｒ（ｉ）の差が閾値以上になれば、演算部６２２は、カウント値Ｒ（ｉ）、Ｒ（ｊ）より移動量を算出する（ステップ１００５）。この時、演算部６２２は後述する補正値を加算する。演算部６２２で算出された移動量は、制御部１１７からトラバースモータ駆動部１０８に伝送される。トラバースモータ駆動部１０８は、伝送された移動量分トラバースモータを駆動する（ステップ１００６）。演算部６２２は、カウント値Ｒ（ｉ）にカウント値Ｒ（ｊ）を設定する（ステップ１００７）。
トラバースモータ駆動終了時には、計算上対物レンズはハウジングの中心にくるはずであるが、実際には時間のずれ、光ディスクのトラックピッチのずれ等の理由により難しい。そのため補正を行う。まず制御部１１７は、トラバースモータ駆動停止時のトラッキングアクチュエータ駆動部１０７が出力するトラッキングアクチュエータの駆動量を検出する（ステップ１００８）。トラッキングアクチュエータの駆動量が大きくなる程、対物レンズがハウジングの中心からずれる。演算部６２２は、補正値を算出し、次回の移動量算出時（ステップ１００５）に移動量を補正するため、算出した補正値を記憶する（ステップ１００９）。ステップ１００３に戻り処理を繰り返す。
【００７２】
実施例４の光ディスク装置及びその制御方法は、実施例３と同様の効果を有する。光ディスクに傷があっても、トラバースモータの制御がその傷の影響を受けることはない。
本実施例においては、トラック３０２に光ピックアップ１０２を追従させ、ＦＧパルスのカウント値の変化が所定の値（閾値）に達した時に、光ディスク装置はトラバースモータ１１０を駆動する。例えば閾値をスピンドルモータ１０回転分のカウント値に設定することにより、対物レンズはハウジング内でトラック本数１０本分以上偏ることが無く、より安定したトラッキング制御を行うことが可能となる。
【００７３】
実施例のＣＤ−ＲＯＭはＣＬＶ方式の光ディスク（セクタ長が一定で、各セクタの始終端が半径方向に整列していない。）であったが、ＣＡＶ方式又はＺＣＡＶ方式等の光ディスクにおいても、本発明を適用出来ることは言うまでもない。多くのＣＡＶ方式又はＺＣＡＶ方式の光ディスクにおいて、各セクタのアドレスは、半径方向の位置情報と、角度方向の位置情報とを持っている。この様な場合、２つの位置の半径方向の距離は、それぞれのアドレスの半径方向の位置情報の差分を計算して、容易に求めることが出来る。
【００７４】
【発明の効果】
本発明によれば、光ディスクに傷等があってもその影響を受けずに、トラバースモータの最適の起動タイミングを遅延なく決定し、安定した記録再生特性を発揮する光ディスク装置及びその制御方法が実現出来るという有利な効果が得られる。
本発明によれば、対物レンズが安定してハウジング内の中心近傍の所定範囲内に位置し、光ピックアップが高い追従性を有する光ディスク装置及びその制御方法が実現出来るという有利な効果が得られる。
【図面の簡単な説明】
【図１】本発明の実施例１、２の光ディスク装置の構成を示すブロック図
【図２】本発明の実施例１の光ディスク装置の制御方法（再生時（トラッキング制御時）のトラバースモータの制御方法）を示すフローチャート
【図３】本発明の実施例１、２、３、４の光ディスクの平面図
【図４】本発明の実施例１の光ディスク装置で傷を有する光ディスクを再生した時（トラッキング制御時）のトラッキング制御量の変化及び光ピックアップ内での対物レンズの位置のずれを示す図
【図５】本発明の実施例２の光ディスク装置の制御方法（再生時（トラッキング制御時）のトラバースモータの制御方法）を示すフローチャート
【図６】本発明の実施例３、４の光ディスク装置の構成を示すブロック図
【図７】本発明の実施例３の光ディスク装置の制御方法（再生時（トラッキング制御時）のトラバースモータの制御方法）を示すフローチャート
【図８】本発明の実施例３の光ディスク装置のＦＧ波形を示す図
【図９】本発明の実施例３の光ディスク装置で傷を有する光ディスクを再生した時（トラッキング制御時）のトラッキング制御量の変化及び光ピックアップ内での対物レンズの位置のずれを示す図
【図１０】本発明の実施例４の光ディスク装置の制御方法（再生時（トラッキング制御時）のトラバースモータの制御方法）を示すフローチャート
【図１１】従来の光ディスク装置の構成を示すブロック図
【図１２】従来の光ディスク装置の制御方法（記録又は再生時（トラッキング制御時）のトラバースモータの制御方法）を示すフローチャート
【図１３】従来の光ディスク装置で光ディスクを記録又は再生した時（トラッキング制御時）のトラッキング制御量の変化及び光ピックアップ内での対物レンズの位置のずれを示す図
【図１４】従来の光ディスクの平面図（ディフェクト有り）
【図１５】従来の光ディスク装置で傷を有する光ディスクを記録又は再生した時（トラッキング制御時）のトラッキング制御量の変化及び光ピックアップ内での対物レンズの位置のずれを示す図
【符号の説明】
１０１、１４０１　光ディスク
１０２　　光ピックアップ
１０３　　スピンドルモータ
１０４　　回転情報検出部
１０５　　スピンドルモータ駆動部
１０６　　フォーカスアクチュエータ駆動部
１０７　　トラッキングアクチュエータ駆動部
１０８　　トラバースモータ駆動部
１０９　　フィード
１１０　　トラバースモータ
１１１　　再生部
１１２　　デコーダ
１１３　　入出力部
１１４　　位置情報検出部
１１５　　トラッキングエラー検出部
１１６　　フォーカスエラー検出部
１１７　　制御部
１１８　　ホストＰＣ
１２１、１１２１　判定部
１２２、６２２　　演算部
３０２、１４０２　トラック
３０３　　セクタ
３０４　　アドレス＝０
３０５　　測定開始アドレス
３０６　　測定終了アドレス
４０１、９０１、１３０１、１５０１　トラッキングオフセット判定レベル
４２１、４２２、４２３　光ピックアップ内での対物レンズの位置
８０１　　ＦＧ波形
８０２　　所定時間内のＦＧ波形のパルス数
８０３　　１回転中のＦＧ波形のパルス数
９２１、９２２、９２３　光ピックアップ内での対物レンズの位置
１３２１、１３２３、１３２４　光ピックアップ内での対物レンズの位置
１４０３　ディフェクト
１５２１、１５２３、１５２４　光ピックアップ内での対物レンズの位置[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical disk device and a control method thereof.
[0002]
[Prior art]
In recent years, the standard mounting of an optical disk device on a personal computer has rapidly progressed, and it has become an indispensable function of a personal computer alongside a hard disk drive. Initially, CD-ROM drives occupied most of the optical disk devices. Recently, however, DVD-ROM drives with higher capacities than CD-ROM drives and writable or rewritable CD-R / CD-RWs have been developed. Drives have become standard on PCs. Furthermore, the performance and functionality of optical disk drives remain unknown, with DVD-R and DVD-RAM drives appearing on the market.
[0003]
The configuration of a conventional optical disk device will be described with reference to FIGS. FIG. 11 is a block diagram showing a configuration of a conventional optical disk device. In FIG. 11, a host PC 118 houses an optical disk device, transmits commands and recording information to the optical disk device, and inputs a response and reproduction information transmitted from the optical disk device. All blocks other than the host PC 118 are included in the optical disk device.
[0004]
In this specification (including conventional examples and embodiments), the optical disk 101 is any optical disk having spiral recording tracks. Any of a read-only optical disk and a writable or rewritable optical disk may be used. Any of a CAV (Constant Angular Velocity) optical disk, a CLV (Constant Linear Velocity) optical disk, a ZCAV (Zone CAV) optical disk, and the like may be used. The information recording method is also arbitrary. For example, an optical disk in which pits are formed on an optical disk, a magneto-optical disk, a phase-change optical disk, and the like. On the optical disk 101, position information indicating a position on the optical disk 101 is recorded. For example, if the optical disc 101 is a CD-ROM, the groove is wobbled to record ATIP (Absolute Time In Pregroove). ATIP includes time information (also position information (address information)). For example, if the optical disc 101 is a DVD, position information is recorded by pre-pits.
[0005]
The optical pickup 102 records information on the optical disk 101 and reads information (including focus error information, position information, user data, and the like) from the optical disk 101.
The optical pickup 102 includes a recording / reproducing laser, an objective lens for forming an image of the laser beam on the optical disc 101, a focus actuator for moving the objective lens in the optical axis direction of the laser beam, and an objective lens. It has a tracking actuator that moves the light beam spot at the center of the recording track by moving it in the width direction of the recording track, a photodetector that inputs reflected laser light and converts it into an electric signal. The focus actuator and the tracking actuator are voice coil motors.
[0006]
The spindle motor driving unit 105 receives a command from the control unit 117 and controls and drives the spindle motor 103 using the rotation information of the spindle motor detected by the rotation information detection unit 104. The spindle motor 103 rotates the optical disc 101.
The focus actuator driving unit 106 drives the focus actuator based on a command from the control unit 117 and a focus error output from the focus error detection unit 116.
The tracking actuator driving unit 107 drives the tracking actuator based on a command from the control unit 117 and a tracking error output from the tracking error detection unit 115.
The traverse motor drive unit 108 drives the traverse motor 110 according to a command from the control unit 117. The traverse motor 110 moves the optical pickup 102 in the radial direction of the optical disk by driving the feed 109 that movably supports the optical pickup 102. In this specification, the traverse motor 110 is a stepping motor. Instead, the traverse motor 110 may be an arbitrary position controllable motor such as a three-phase drive motor.
[0007]
A decoder 112 converts an analog signal output from the reproducing unit 111 into a digital signal and decodes the digital signal. 113 denotes an input / output unit. 114 denotes a position information detecting unit. 115 denotes a tracking error detecting unit. 116 denotes a focus error detecting unit. The control unit 118 is a host computer (hereinafter abbreviated as “host PC”).
The input / output unit 113 transmits a command from the host PC 118 to the control unit 117, and transmits a response from the control unit 117 to the host PC 118. The input / output unit 113 transmits the input recording information to the encoder 1102, and outputs a reproduction signal decoded by the decoder 112.
The encoder 1102 encodes the input recording information. The recording unit 1101 supplies a recording current to a semiconductor laser (built in the optical pickup 102) according to the encoded recording information.
[0008]
The reproduction unit 111 amplifies a reproduction signal (including focus error information, position information, user data, and the like) detected by the photodetector of the optical pickup 102. The decoder 112 decodes the reproduced signal output by the reproducing unit 111.
The position information detection unit 114 detects position information from the reproduction signal output by the reproduction unit 111 and transmits the position information to the control unit 118.
The control unit 117 controls each block of the optical disk device in accordance with a command from the host PC 118. In the present specification (including the conventional example and the embodiment), the control unit 117 is a microcomputer (having a CPU). The control unit 117 includes a determination unit 1121.
[0009]
Next, the operation of the conventional optical disk device during recording or reproduction will be described (the recording speed and the reproduction speed are arbitrary). The rotation of the optical disk 101 is controlled by a spindle motor 103 at a constant linear velocity or a constant angular velocity. The optical pickup 102 irradiates the rotating optical disk 101 with laser light on the optical disk surface while moving in the radial direction from the inner peripheral side to the outer peripheral side of the optical disk by the traverse motor 110, and changes the reflected light to the optical disk. The information recorded above is read (if the optical disk is recordable, information can be recorded on the optical disk). For example, pits are formed on a spiral track on the optical disc in accordance with recording data.
[0010]
At the time of recording or reproduction, the focus actuator drive unit 106 performs focus control so that the optical pickup 102 can accurately read information recorded on a spiral track. The focus error detection unit 116 detects a focus error (defocus) based on a change in laser reflected light from the optical disc surface on which a groove is formed along a recording track. The focus actuator driven by the focus actuator drive unit 106 drives an objective lens supported by a wire in a housing in the optical pickup 102 perpendicular to the optical disk surface so that a focus error is minimized. Thereby, the laser light can be focused on the optical disk surface.
At the time of recording or reproduction, the tracking actuator drive unit 107 performs tracking control so that the laser beam is located at the center of the recording track. The tracking error detection unit 115 detects a tracking error (deviation from the track center) based on a change in laser reflected light from the optical disc surface on which a groove is formed along a recording track. The tracking actuator driven by the tracking actuator driving unit 107 moves the objective lens supported by a wire in a housing in the optical pickup 102 in the radial direction (the width direction of the recording track) with respect to the optical disk surface so as to minimize the tracking error. ) To drive horizontally. Thereby, the laser beam can be adjusted to the position of the track.
[0011]
The objective lens whose focus and tracking are controlled reads information from a recording track of the optical disc 101 or records information on the recording track. At the time of reproduction, the optical pickup 102 converts the detected reflected light into an electric signal (reproduction signal) and sends it to the reproduction unit 111. The reproduction signal is transmitted to the host PC 118 via the reproduction unit 111, the decoder 112, and the input / output unit 113.
[0012]
Since the recording track is formed in a spiral shape, the light beam spot for recording or reproduction (laser light focused on the optical disk by the objective lens) must move from the inner circumference to the outer circumference of the optical disk with the passage of time. . The optical disk device moves the light beam spot by using two different methods. The first method is to move the objective lens in the housing of the optical pickup 102 by a tracking actuator. The tracking actuator drives the objective lens at a high response frequency, but can only displace the objective lens to a certain extent in the housing. The second method is a method in which the feed 109 is driven by the traverse motor 110 to move the entire optical pickup 102. The traverse motor 110 has a lower frequency response than the tracking actuator, but can move the light beam spot to an arbitrary position on the optical disk.
[0013]
FIG. 12 is a flowchart showing a conventional method of controlling an optical disk device (a method of controlling a traverse motor during recording or reproduction (at the time of tracking control)).
At the time of recording / reproducing, the tracking actuator moves the objective lens to control the light beam spot to be located at the center of the track (this control is always executed). As the position of the light beam spot moves toward the outer periphery of the optical disk, the objective lens gradually shifts from the center of the housing. The control unit 117 detects a DC component (offset amount) of the tracking control amount output from the tracking actuator driving unit 107 (Step 1201). As the tracking control amount of the tracking actuator drive unit 107 increases, the objective lens shifts from the center of the housing.
[0014]
Next, the determination unit 1121 checks whether the tracking control amount of the tracking actuator driving unit 107 has become larger than the first threshold value 1301 (step 1202). If the tracking control amount is smaller than the first threshold, the process returns to step 1201.
If the tracking control amount of the tracking actuator drive unit 107 becomes larger than the first threshold value 1301, the determination unit 1121 drives the traverse motor 110 to move the entire optical pickup 102 (step 1203). As the optical pickup 102 itself moves, the position of the objective lens in the housing returns to near the center.
The control unit 117 detects a DC component (offset amount) of the tracking control amount output from the tracking actuator driving unit 107 (Step 1204).
This time, the determination unit 1121 checks whether the tracking control amount of the tracking actuator driving unit 107 has become smaller than the second threshold value 1303 (step 1205). If the tracking control amount is larger than the second threshold, the process returns to step 1204.
If the tracking control amount of the tracking actuator drive unit 107 becomes smaller than the second threshold value 1303, the determination unit 1121 stops the traverse motor 110 and returns to step 1201.
[0015]
FIG. 13 is a diagram showing a change in the amount of tracking control (1302) when recording or reproducing an optical disk in the conventional optical disk device (during tracking control), and a shift in the position of the objective lens in the optical pickup 102.
1301 is a first threshold (tracking offset determination level), 1302 is a tracking control amount in a conventional optical disk device, and 1303 is a second threshold. Reference numerals 1321, 1323, and 1324 denote positions of the objective lens in the optical pickup.
At the time of recording or reproduction (at the time of tracking control), as the tracking actuator drive unit 107 moves the objective lens to make the light beam spot follow the recording track, the tracking control amount 1302 increases (1311-1313), and the objective lens Move in the housing (1321-1323). When the state where the tracking control amount 1302 exceeds the first threshold value 1301 continues for a certain period of time (1312-1313), the determining unit 1121 determines to drive the traverse motor 110. The optical disc device drives the traverse motor 110 to move the feed 109, and returns the objective lens to the center of the housing (1313-1314, 1323-1324). When the objective lens returns to the center of the housing (1314, 1324) and the tracking control amount 1302 becomes smaller than the second threshold value 1303, the determination unit 1121 determines to stop the traverse motor 110. The traverse motor 110 stops.
[0016]
[Problems to be solved by the invention]
However, since the tracking control amount constantly fluctuates during tracking, the determination unit 1121 performs tracking for a predetermined time (period of 1312 to 1313) to determine whether the tracking control amount 1302 exceeds the first threshold value 1301. It is necessary to take in the control amount. The traverse motor 110 is not driven until the objective lens is offset to some extent (1313). Therefore, the driving of the traverse motor 110 may be slightly delayed.
[0017]
FIG. 14 illustrates an optical disc 1401 having a scratch 1403 on a recording track 1402. The tracking control amount may be largely disturbed by scratches, defects, dirt, etc. on the optical disc 1401 (1403 in FIG. 14).
FIG. 15 shows a change in the amount of tracking control (solid line 1503) when the optical disk 1401 having a flaw 1403 is recorded or reproduced (at the time of tracking control) in the conventional optical disk device, and a shift in the position of the objective lens in the optical pickup 102. FIG.
Reference numeral 1501 denotes a first threshold value (tracking offset determination level), a broken line 1502 denotes a tracking control amount in a normal optical disk device in a normal case, and a solid line 1503 denotes a determination unit 1121 in the conventional optical disk device to determine activation of a traverse motor. This is a tracking control amount when the timing is delayed. Reference numerals 1521, 1523, and 1524 denote positions of the objective lens in the optical pickup.
[0018]
At the time of recording or reproduction (at the time of tracking control), as the tracking actuator drive unit 107 moves the objective lens so that the light beam spot follows the recording track, the tracking control amount 1302 increases (1511 to 1513). Are displaced within the housing (1521-1523). Normally, when the state where the tracking control amount 1502 exceeds the first threshold value 1501 continues for a certain period of time (1512-1513), the determination unit 1121 determines to drive the traverse motor 110. However, if there is a scratch on the disk, the tracking error detection unit 117 may detect an erroneous tracking error due to the scratch, and the tracking actuator drive unit 107 may output an erroneous tracking control amount based on the erroneous tracking error. . In this case, the determination unit 1121 cannot determine the activation of the traverse motor 110 during the period of 1512 to 1513, and can determine the activation of the traverse motor 110 only during the period of 1512 to 1514.
[0019]
As a result of the drive start timing of the traverse motor 110 being delayed from 1513 to 1514, at 1514, the objective lens is greatly offset from the center of the housing (1524). The optical disk device is designed to have the best recording and reproduction characteristics when the objective lens is located at the center of the housing. For this reason, in the state of 1524, there is a possibility that the recording / reproducing characteristics of the optical disk device may be deteriorated.
SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problem and to provide an optical disk device in which the operation timing of a traverse motor is not affected by a scratch or the like of an optical disk. SUMMARY OF THE INVENTION It is an object of the present invention to provide an optical disk device that determines the start timing of a traverse motor without delay.
ADVANTAGE OF THE INVENTION According to this invention, even if an optical disk has a flaw etc., a traverse motor can be started at an optimal timing, and it can prevent that an objective lens displaces excessively in a housing.
[0020]
[Means for Solving the Problems]
In order to solve the above problems, the present invention has the following configurations.
According to a first aspect of the present invention, there is provided an objective lens for imaging a light beam spot on an optical disk, a tracking actuator for driving the objective lens in a width direction of a recording track of the optical disk, and an optical pickup including the objective lens. A traverse motor driven in a radial direction of the optical disc, position information detecting means for detecting position information recorded on the optical disc, and a movement amount of the light beam spot moved in a radial direction of the optical disc, Calculating means for calculating using the information, at predetermined time intervals, calculating the moving amount of the light beam spot by the calculating means, driving the traverse motor and moving the optical pickup with the moving amount. An optical disc device characterized by moving by the same amount.
[0021]
According to a second aspect of the present invention, there is provided an objective lens for imaging a light beam spot on an optical disk, a tracking actuator for driving the objective lens in a width direction of a recording track of the optical disk, and an optical pickup including the objective lens. A traverse motor driven in a radial direction of the optical disc, position information detecting means for detecting position information recorded on the optical disc, and a movement amount of the light beam spot moved in a radial direction of the optical disc, Computing means for calculating using information, and each time the movement amount of the light beam spot reaches a predetermined amount, the traverse motor is driven to move the optical pickup by the same amount as the movement amount. An optical disc device characterized by causing the
[0022]
According to a third aspect of the present invention, there is provided a spindle motor for rotating an optical disk, an objective lens for imaging a light beam spot on the optical disk, and a tracking actuator for driving the objective lens in a width direction of a recording track of the optical disk. A traverse motor for driving an optical pickup including the objective lens in a radial direction of the optical disk; rotation information detecting means for detecting rotation of the spindle motor; and movement of the optical beam spot in a radial direction of the optical disk. Calculating means for calculating the amount by using the rotation information, calculating the moving amount of the light beam spot by the calculating means at predetermined time intervals, driving the traverse motor, and driving the optical pickup. An optical disk drive characterized in that the optical disk drive is moved by the same amount as the movement amount. It is.
[0023]
According to a fourth aspect of the present invention, there is provided a spindle motor for rotating an optical disk, an objective lens for imaging a light beam spot on the optical disk, and a tracking actuator for driving the objective lens in a width direction of a recording track of the optical disk. A traverse motor for driving an optical pickup including the objective lens in a radial direction of the optical disk; rotation information detecting means for detecting rotation of the spindle motor; and movement of the optical beam spot in a radial direction of the optical disk. Calculating means for calculating the amount using the rotation information, each time the amount of rotation of the spindle motor reaches a predetermined amount or every time the amount of movement of the light beam spot reaches a predetermined amount, Driving a traverse motor to move the optical pickup by the same amount as the movement amount Preparative an optical disk apparatus according to claim.
[0024]
According to a fifth aspect of the present invention, the arithmetic unit has a counter and an arithmetic processing unit (hereinafter, referred to as “CPU”), and the counter uses an output signal of the rotation information detecting unit as a clock signal. By inputting and counting, the number of rotations of the spindle motor is detected, and the CPU calculates the amount of movement of the light beam spot in the radial direction of the optical disk based on the number of rotations. An optical disc device according to claim 3 or claim 4.
[0025]
The invention according to claim 6 is a CPU in which the arithmetic means has an external interrupt terminal, wherein the CPU inputs an output signal of the rotation information detecting means to an external interrupt terminal, and interrupts the external interrupt terminal. 5. The optical disk device according to claim 3, wherein the number of times is counted, and the amount of movement of the light beam spot in the radial direction of the optical disk is calculated based on the number of interruptions.
[0026]
The invention according to claim 7 is
When the traverse motor is driven to move the optical pickup by the same amount as the movement amount, a value of a tracking error or a drive amount of the tracking actuator is detected, and the value of the tracking error or the If the driving amount of the tracking actuator exceeds a certain range, the value of the tracking error or the driving amount of the tracking actuator at the time when the driving of the traverse motor is completed during the next driving of the traverse motor is constant. The optical disk device according to any one of claims 1 to 4, wherein the amount of movement of the optical pickup by the traverse motor is corrected so as to fall within the range described in (1).
[0027]
The invention according to claim 8 includes an objective lens that forms a light beam spot on an optical disk, a tracking actuator that drives the objective lens in a width direction of a recording track of the optical disk, and an optical pickup that includes the objective lens. A traverse motor for driving the optical disk in a radial direction, wherein the optical disk device detects position information recorded on the optical disk, and uses the position information at predetermined time intervals. An optical disc comprising: a calculating step of calculating a moving amount of a beam spot; and a moving step of driving the traverse motor to move the optical pickup by the same amount as the moving amount at predetermined time intervals. It is a control method of the device.
[0028]
According to a ninth aspect of the present invention, there is provided an objective lens for imaging a light beam spot on an optical disk, a tracking actuator for driving the objective lens in a width direction of a recording track of the optical disk, and an optical pickup including the objective lens. A traverse motor that drives the optical disk in a radial direction, wherein the optical disk device detects position information recorded on the optical disk, and uses the position information to change the light beam spot on the optical disk. A calculating step of calculating a moving amount moved in a radial direction, and a moving step of driving the traverse motor to move the optical pickup by the same amount as the moving amount each time the moving amount reaches a predetermined amount. And a control method for an optical disk device.
[0029]
A tenth aspect of the present invention provides a spindle motor for rotating an optical disc, an objective lens for imaging a light beam spot on the optical disc, and a tracking actuator for driving the objective lens in a width direction of a recording track of the optical disc. A traverse motor that drives an optical pickup including the objective lens in a radial direction of the optical disk, the method comprising: detecting rotation of the spindle motor; Calculating the amount of movement of the optical beam spot in the radial direction of the optical disk by using the method, and driving the traverse motor to move the optical pickup by the same amount as the amount of movement every predetermined time. Moving the optical disk device. It is your way.
[0030]
The invention according to claim 11, wherein a spindle motor for rotating the optical disc, an objective lens for forming an optical beam spot on the optical disc, and a tracking actuator for driving the objective lens in a width direction of a recording track of the optical disc. A traverse motor that drives an optical pickup including the objective lens in a radial direction of the optical disk, the method comprising: detecting rotation of the spindle motor; Calculating a movement amount of the beam spot moved in the radial direction of the optical disk; and driving the traverse motor every time the rotation amount of the spindle motor reaches a predetermined amount or each time the movement amount reaches a predetermined amount. To move the optical pickup by the same amount as the amount of movement. A control method of the optical disk apparatus characterized by comprising: a step, the.
[0031]
According to a twelfth aspect of the present invention, a value of a tracking error or a driving amount of the tracking actuator is detected when the traverse motor is driven to move the optical pickup by the same amount. If the value of the tracking error or the drive amount of the tracking actuator exceeds a certain range, the value of the tracking error at the time of driving the traverse motor at the time of driving the next traverse motor is completed. 12. The optical disk according to claim 8, further comprising a correction step of correcting a movement amount of the optical pickup by the traverse motor so that a driving amount of the tracking actuator falls within a predetermined range. It is a control method of the device.
[0032]
According to the present invention, since the moving distance of the objective lens (displacement from the center in the housing) can be accurately obtained without delay without using the tracking control amount, the optimal start timing of the traverse motor can be determined without delay. Can be determined. According to the present invention, since the traverse motor can be started at an optimum timing without being affected by the scratch or the like on the optical disc, it is possible to prevent the objective lens from being excessively displaced in the housing. Thereby, the objective lens is stably positioned within a predetermined range near the center in the housing, and high followability of the optical pickup with respect to the track can be secured.
According to the present invention, it is possible to realize an optical disk apparatus and a control method thereof, in which an optical pickup has high followability, a tracking control system is hardly affected by scratches or the like of an optical disk, and exhibits stable recording and reproduction characteristics. .
[0033]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment that specifically shows the best mode for carrying out the present invention will be described with reference to the drawings.
[0034]
<< Example 1 >>
First Embodiment An optical disk device according to a first embodiment of the present invention will be described with reference to FIGS. The optical disk of the first embodiment is a CD-ROM (compact optical disk) (as described in the conventional example, any other optical disk may be used). In the CD-ROM, information is reproduced by a CLV method in which the linear velocity is constant and the rotational speed changes depending on the reproduction position on the optical disk.
[0035]
First, the structure of the optical disc according to the first embodiment will be described. FIG. 3 is a plan view of the optical disc according to the first embodiment of the present invention. FIG. 3 shows track and address information on the optical disk.
In FIG. 3, reference numeral 302 denotes one recording track spirally extending from the inner circumference to the outer circumference on the optical disc 101. On this recording track, pits (convex portions) having information are formed. The recording area for one round of the optical disk is counted as one track. Further, one track is divided into a plurality of sectors 303 and managed. The sector 303 is the minimum address unit on the optical disk 101, and data is read and written in sector units. In the CLV system, the length of a sector is constant. The address = 0 (304) at the innermost circumference (at a radius of 25 mm) of the optical disk, and the addresses increase from 1, 2, 3,... The outermost radius of the CD-ROM is 58 mm. Each sector has address information (time information), and by obtaining this, the position of the beam spot on the optical disk 101 can be known.
[0036]
Next, the configuration of the optical disk device according to the first embodiment will be described. FIG. 1 is a block diagram illustrating a configuration of an optical disc device according to a first embodiment of the present invention. The optical disk device of the first embodiment (FIG. 1) has a configuration similar to that of the conventional optical disk device (FIG. 11). In FIG. 1, the same blocks as those in the conventional example (FIG. 11) are denoted by the same reference numerals. Description of the same blocks as in the conventional example will be omitted.
In the conventional example (FIG. 11), the control unit 117 has a determination unit 1121. Instead, the control unit 117 according to the first embodiment (FIG. 1) includes a determination unit 121 and a calculation unit 122. In the conventional example (FIG. 11), the recording unit 1101 and the encoder 1102 are provided. However, since the optical disk of the first embodiment (FIG. 1) is a CD-ROM (Compact Disc Read Only Memory), these functions are provided. do not do. Otherwise, the first embodiment (FIG. 1) is the same as the conventional example (FIG. 11).
[0037]
The determining unit 121 has a timer (time measuring unit). At the time of reproduction (at the time of tracking control), the determination unit 121 determines whether or not a predetermined time has elapsed, and instructs the start of the traverse motor every predetermined time. At the innermost circumference of the optical disk, the predetermined time is determined so that the amount of displacement of the objective lens within the housing within the predetermined time falls within a range in which good recording and reproduction characteristics can be exhibited.
The calculation unit 122 inputs and stores the position information output by the position information detection unit 116 every time the determination unit 121 instructs the start of the traverse motor (every predetermined time). The calculation unit 122 calculates the distance that the light beam spot has moved in the radial direction of the optical disc from the change in the position information from the previous input of the traverse motor start command to the current input of the traverse motor start command. At this time, it is preferable to add a correction value described later. The control unit 118 sends a command to the traverse motor drive unit 108 to drive the traverse motor 110 by the distance calculated by the calculation unit 122. Thereby, the objective lens returns to the vicinity of the center in the housing.
[0038]
The calculation unit 122 calculates the distance by which the light beam spot has moved in the radial direction of the optical disk as accurately as possible. However, since there is an error and an error of the optical disk itself, the housing of the objective lens after driving the traverse motor 110 is calculated. Position may slightly deviate from the target position.
The calculation unit 122 receives a tracking error (an output signal of the tracking error detection unit 117) immediately after the traverse motor 110 completes the movement. If the value of the tracking error exceeds a predetermined range, a correction value according to the value of the tracking error is set. Next, when a traverse motor start command is input, the calculation unit 122 adds the correction value to the distance calculated from the position information. Thereby, accumulation of errors can be prevented. Preferably, the calculation unit 122 inputs a tracking error immediately after the traverse motor 110 completes the movement a plurality of times, and calculates an average value of the plurality of tracking errors. As a result, it is possible to remove the influence of the fine fluctuation of the tracking error. Since the speed at which errors accumulate is slow, delays caused by inputting tracking errors a plurality of times are not a problem.
[0039]
A method in which the calculation unit 122 calculates the moving distance of the light beam spot in the radial direction (moving distance of the optical pickup 102) every predetermined time during reproduction will be described. First, assuming that the light beam spot is located at the address 305 (measurement start address; FIG. 3) on the optical disk 101 and arrives at the address 306 (measurement end address) after a predetermined time, the following formula (1) is obtained. Holds. Where A ^** Is the address value of the address ** (the number of sectors from address = 0), T ^** Is the number of tracks from address = 0 to address **, V is the length (mm) of one sector, and P is the track pitch (mm). In the CD-ROM, an address = 0 at a position with a radius of 25 mm.
[0040]
(Equation 1)

[0041]
By solving the equation (1), the following equation (2) is obtained.
[0042]
(Equation 2)

[0043]
Therefore, the number of track crossings T from address 305 (measurement start address) to address 306 (measurement end address) ^** (Position 306-Position 305) is calculated from Expression (2) by T ^** (Position 306) -T ^** (Position 305). If this result is further multiplied by the track pitch P, the radial distance (movement distance of the light beam spot from address 305 (measurement start address) to address 306 (measurement end address). The optical pickup 102 is moved by the traverse motor 110. Distance).
[0044]
FIG. 2 is a flowchart illustrating a control method of the optical disc apparatus (control method of the traverse motor during reproduction (at the time of tracking control)) according to the first embodiment of the present invention.
At the time of reproduction, the determination unit 121 starts a timer (step 201), and sets a timer value to 0 (initial value) (continues timer operation) (step 202). The operation unit 122 detects the current position information P (i) output from the position information detection unit 114 (Step 203).
The tracking actuator moves the objective lens to control the light beam spot to be located at the center of the track (this control is always performed). As the position of the light beam spot moves toward the outer periphery of the optical disk, the objective lens gradually shifts from the center of the housing. The determination unit 121 checks whether a predetermined time has elapsed (step 204). This process is repeated until a predetermined time has elapsed.
[0045]
After a predetermined time has elapsed, the determination unit 121 returns the timer value to 0 (initial value) (timer operation continues) (step 205). The arithmetic unit 122 adds 1 to i (step 206), and detects the position information P (i) after the elapse of the predetermined time output from the position information detecting unit 114 (step 207). The calculation unit 122 calculates the movement amount from the position information P (i-1) and P (i) (Step 208). At this time, the calculation unit 122 adds a correction value described later. The movement amount calculated by the calculation unit 122 is transmitted from the control unit 117 to the traverse motor drive unit 108. The traverse motor drive unit 108 drives the traverse motor by the transmitted movement amount (step 209).
At the end of driving the traverse motor, the objective lens should be at the center of the housing for calculation, but it is actually difficult due to time lag, track pitch lag of the optical disk, and the like. Therefore, correction is performed. First, the control unit 117 detects a tracking error value output by the tracking actuator driving unit 107 when driving the traverse motor is stopped (step 210). The operation unit 122 checks whether the absolute value of the tracking error is larger than a threshold (step 211). As the absolute value of the tracking error increases, the objective lens shifts from the center of the housing. If the difference is larger than the threshold value, the calculation unit 122 calculates a correction value and stores the calculated correction value to correct the movement amount at the time of the next movement amount calculation (step 208) (step 212). If the difference is smaller than the threshold, the calculation unit 122 sets the correction value to 0 (step 213). Returning to step 204, the process is repeated.
[0046]
ADVANTAGE OF THE INVENTION According to this invention, even if an optical disk has a flaw etc., it becomes possible to perform tracking control during recording or reproduction (at the time of tracking control) without the objective lens being biased in the housing.
This will be specifically described with reference to FIG. FIG. 4 shows the change in the tracking control amount (solid line 402) and the displacement of the objective lens in the optical pickup 102 when the scratched optical disk is reproduced by the optical disk apparatus according to the first embodiment of the present invention (during tracking control). FIG. For comparison, broken lines 403 and 404 show changes in the tracking control amount in the conventional example. Reference numeral 401 denotes a threshold (tracking offset determination level) in the conventional example. Reference numerals 421, 422, and 423 indicate positions of the objective lens in the optical pickup.
In the periods 411 to 412, the optical disk device drives the tracking actuator to move the objective lens while the traverse motor 110 is stopped, so that the light beam spot follows the recording track. At the same time, the optical disc device calculates the number of tracks to which the light beam spot has moved from a change in time information on the optical disc 101 at predetermined time intervals. At predetermined time intervals (position 412), the optical disk device drives the traverse motor 110 to move the feed 109, and returns the objective lens to the center of the housing (412 to 413). When the objective lens returns to the center of the housing (413), the driving of the traverse motor 110 ends. Thereby, stable recording / reproducing characteristics can be obtained.
[0047]
In the conventional optical disc device, after the tracking control amount reaches the threshold (tracking offset determination level), the determination unit cannot determine the activation of the traverse motor until a certain period elapses. Therefore, a response delay as shown by a solid line 403 occurred. Since the value of the tracking error greatly fluctuates in a portion where the optical disc has a flaw, the timing at which the determination unit determines to start the traverse motor is further delayed, and a response shown by a solid line 404 occurs.
In the optical disk device of the present invention, a response delay as indicated by the solid line 403 does not occur, and even if the optical disk is damaged, it is not affected.
[0048]
<< Example 2 >>
Second Embodiment An optical disc device according to a second embodiment of the present invention will be described with reference to FIGS. The optical disk of the second embodiment is a CD-ROM (compact optical disk) (as described in the conventional example, any other optical disk may be used). In the CD-ROM, information is reproduced by a CLV method in which the linear velocity is constant and the rotational speed changes depending on the reproduction position on the optical disk.
[0049]
The structure of the optical disk has already been described with reference to FIG.
Next, the configuration of the optical disk device according to the second embodiment will be described. FIG. 1 is a block diagram illustrating a configuration of an optical disk device according to a second embodiment of the present invention. FIG. 1 has been described in the first embodiment. In the second embodiment, the operations of the determination unit 121 and the operation unit 122 are different from those of the first embodiment. Otherwise, the second embodiment is the same as the first embodiment.
[0050]
In the second embodiment, the traverse motor is driven each time the light beam spot moves a predetermined distance in the radial direction of the optical disc during reproduction (at the time of tracking control). The calculating unit 122 of the second embodiment inputs and stores the position information output by the position information detecting unit 116 every time the determining unit 121 instructs the activation of the traverse motor. The calculation unit 122 according to the second embodiment calculates an address (a target position at which the traverse motor is started next) at a position moved by a predetermined distance (threshold) from the position of the light beam spot at the time of the previous traverse motor start command input. . The calculation method is the same as that of the first embodiment (the unknown number is A ** instead of T **). At this time, it is preferable to add the correction value described in the first embodiment.
[0051]
The determination unit 121 according to the second embodiment determines whether or not the distance by which the light beam spot has moved in the radial direction of the optical disk is equal to or greater than a predetermined threshold (whether or not the address of the light beam spot is a value larger than the target address calculated by the calculation unit 122). Is determined. If the moving distance is equal to or larger than the predetermined threshold, the determination unit 121 instructs the activation of the traverse motor. The control unit 118 sends a command to the traverse motor drive unit 108 to drive the traverse motor 110 by the distance calculated by the calculation unit 122. Thereby, the objective lens returns to the vicinity of the center in the housing.
The second embodiment is characterized in that the drive amount of one traverse motor 110 is substantially constant from the inner circumference to the outer circumference of the CLV optical disk. One driving amount of the traverse motor 110 is large, and becomes smaller as it moves to the outer periphery.) With respect to the CAV optical disk, the optical disk device of the second embodiment operates in the same manner as the first embodiment.
[0052]
FIG. 5 is a flowchart illustrating a control method of the optical disc apparatus (control method of the traverse motor during reproduction (at the time of tracking control)) according to the second embodiment of the present invention.
At the time of reproduction, the calculation unit 122 first detects and stores the current position information P (i) (position information of the starting point) output by the position information detection unit 114 (step 501). Further, the operation unit 122 detects the new current position information P (j) output from the position information detection unit 114 (Step 502). The calculation unit 122 checks whether or not the difference between the position information P (j) and P (i) is larger than a threshold (Step 503). While the difference between the position information P (j) and P (i) is smaller than the threshold value, the process returns to step 502 and repeats the process.
If the difference between the position information P (j) and P (i) is equal to or larger than the threshold value, the calculation unit 122 calculates the movement amount from the position information P (i) and P (j) (Step 504). At this time, the calculation unit 122 adds a correction value described later. The movement amount calculated by the calculation unit 122 is transmitted from the control unit 117 to the traverse motor drive unit 108. The traverse motor drive unit 108 drives the traverse motor by the transmitted movement amount (Step 505). The operation unit 122 sets the position information P (j) as the position information P (i) (Step 506).
[0053]
At the end of driving the traverse motor, the objective lens should be at the center of the housing for calculation, but it is actually difficult due to time lag, track pitch lag of the optical disk, and the like. Therefore, correction is performed. First, the control unit 117 detects the driving amount of the tracking actuator output by the tracking actuator driving unit 107 when the traverse motor is stopped (step 507). The calculation unit 122 checks whether the driving amount of the tracking actuator is larger than a threshold (step 508). As the driving amount of the tracking actuator increases, the objective lens shifts from the center of the housing. If it is larger than the threshold value, the calculation unit 122 calculates a correction value, and stores the calculated correction value in order to correct the movement amount at the time of the next movement amount calculation (step 504) (step 509). If the difference is smaller than the threshold, the calculation unit 122 sets the correction value to 0 (step 510). Returning to step 502, the process is repeated.
[0054]
The optical disc device and the control method of the second embodiment have the same effects as the first embodiment. Even if the optical disc has a flaw, the control of the traverse motor is not affected by the flaw.
In the present embodiment, the optical pickup 102 is caused to follow the track 302, and the optical disk apparatus drives the traverse motor 110 when the moving distance of the light beam spot in the radial direction reaches a predetermined number. For example, by setting the predetermined number to ten, the objective lens is not deviated by more than ten tracks in the housing, and more stable tracking control can be performed.
[0055]
<< Example 3 >>
Third Embodiment An optical disc device according to a third embodiment of the present invention will be described with reference to FIGS. The optical disc of the third embodiment is a CD-ROM (compact optical disc) (as described in the conventional example, any other optical disc may be used). In the CD-ROM, information is reproduced by a CLV method in which the linear velocity is constant and the rotational speed changes depending on the reproduction position on the optical disk.
[0056]
The structure of the optical disk has already been described with reference to FIG.
Next, the configuration of the optical disk device according to the third embodiment will be described. FIG. 6 is a block diagram showing the configuration of the optical disk device according to the third embodiment of the present invention. The optical disk device of the third embodiment (FIG. 6) has a configuration similar to that of the optical disk device of the first embodiment (FIG. 1). In FIG. 6, the same blocks as in the first embodiment (FIG. 1) are denoted by the same reference numerals. Description of the same blocks as in the first embodiment will be omitted.
In the first embodiment (FIG. 1), the control unit 118 includes the determination unit 121 and the calculation unit 122. Instead, the control unit 118 according to the third embodiment (FIG. 6) includes a determination unit 121 and a calculation unit 622. Otherwise, Example 3 (FIG. 6) is the same as Example 1 (FIG. 1).
[0057]
The determining unit 121 has a timer (time measuring unit). At the time of recording or reproduction (at the time of tracking control), the determination unit 121 determines whether or not a predetermined time has elapsed, and instructs activation of the traverse motor every predetermined time. At the innermost circumference of the optical disk, the predetermined time is determined so that the amount of displacement of the objective lens within the housing within the predetermined time falls within a range in which good recording and reproduction characteristics can be exhibited.
The arithmetic unit 622 inputs and stores the rotation information of the spindle motor 103 output by the rotation information detection unit 104 every time the determination unit 121 instructs the activation of the traverse motor (every predetermined time). The calculation unit 622 calculates the light beam spot from the number of rotations of the spindle motor 103 (the count value of the rotation pulse, which is rotation information) during the period from the previous traverse motor start command input to the current traverse motor start command input. Calculates the distance that has moved in the radial direction of the optical disk. At this time, it is preferable to add the correction value described in detail in the first embodiment. The control unit 118 sends a command to the traverse motor drive unit 108 to drive the traverse motor 110 by the distance calculated by the calculation unit 622. Thereby, the objective lens returns to the vicinity of the center in the housing.
[0058]
FIG. 8 is a diagram showing an FG waveform of the optical disk device according to the third embodiment of the present invention. In FIG. 8, an FG (Frequency Generator) pulse generator is mounted on the spindle motor 103 as the rotation information detecting unit 104. The rotation information detection unit 104 outputs an FG pulse according to the rotation of the optical disk. The rotation angle of the spindle motor can be detected by counting the number of FG pulses, and the rotation speed of the spindle motor can be detected by counting the number of FG pulses generated within a predetermined time.
[0059]
A method in which the calculation unit 622 calculates the moving distance of the light beam spot in the radial direction (the moving distance of the optical pickup 102) at every predetermined time during reproduction will be described. Assuming that the beam spot is located at the address 305 (measurement start address; FIG. 3) on the optical disc 101, and assuming that the beam spot comes to the address 306 (measurement end address) after a predetermined time, the following formula (3) is established. Here, FG is the number of FG pulses within a predetermined time, n is the number of FG pulses during one rotation, and P is the track pitch (mm).
L = (FG / n) · P (3)
[0060]
The number of pulses 802 (FG) of the FG waveform 801 within a predetermined time is measured, and this is divided by the number of pulses 803 (n) of the FG waveform 801 during one rotation to obtain the spindle motor 103 within a predetermined time. Can be determined (FG / n). If the spindle motor 103 makes one rotation, the optical pickup 102 following the track 302 moves one track. Therefore, if the number of rotations is multiplied by the track pitch P, the light beam spot moves within a predetermined time. The distance (distance that the optical pickup 102 is moved by the traverse motor 110) L can be calculated.
[0061]
The calculation unit 622 according to the third embodiment includes a counter and a program executed by the control unit 118 that is a microcomputer (including a CPU). The counter is a binary counter that receives an FG pulse and counts up. When the determination unit 121 (which is a program executed by the control unit 118 which is a microcomputer) instructs activation of the traverse motor, the calculation unit 622 (a program executed by the microcomputer) inputs a counter value at that time. ,Remember. The calculation unit 622 calculates the difference between the counter value at the time of the previous command to start the traverse motor and the current counter value, and calculates the moving distance of the light beam spot.
[0062]
Instead of this, the calculation unit 622 of the third embodiment may be a program executed by the control unit 118 which is a microcomputer (including a CPU) having an external interrupt terminal.
An FG pulse is input to the external interrupt terminal. When an external interrupt occurs, the microcomputer (control unit 118) executes a binary counter program (interrupt program) that counts and stores FG pulses. When the determination unit 121 (which is a program executed by the control unit 118 which is a microcomputer) instructs activation of the traverse motor, the calculation unit 622 (a program executed by the microcomputer) outputs a counter value (interrupt program) at that time. Is read out and stored. The calculation unit 622 calculates the difference between the counter value at the time of the previous command to start the traverse motor and the current counter value, and calculates the moving distance of the light beam spot.
[0063]
FIG. 7 is a flowchart illustrating a control method of the optical disc apparatus (control method of the traverse motor during reproduction (at the time of tracking control)) according to the third embodiment of the present invention.
At the time of reproduction, first, the determination unit 121 starts a timer (Step 701), and the rotation information detection unit 104 starts a counter of a rotation pulse of the spindle motor (Step 702). The determining unit 121 sets the timer value to 0 (initial value) (timer operation continues) (step 703). The calculation unit 622 detects the current count value R (i) output by the rotation information detection unit 104 (Step 704).
The tracking actuator moves the objective lens to control the light beam spot to be located at the center of the track (this control is always performed). As the position of the light beam spot moves toward the outer periphery of the optical disk, the objective lens gradually shifts from the center of the housing. The determining unit 121 checks whether a predetermined time has elapsed (step 705). This process is repeated until a predetermined time has elapsed.
[0064]
After a predetermined time has elapsed, the determination unit 121 returns the timer value to 0 (initial value) (timer operation continues) (step 706). Arithmetic unit 622 adds 1 to i (step 707), and detects count value R (i) after a lapse of a predetermined time output from rotation information detecting unit 104 (step 708). The calculation unit 622 calculates the movement amount from the count values R (i-1) and R (i) (Step 709). At this time, the calculation unit 622 adds a correction value described later. The movement amount calculated by the calculation unit 622 is transmitted from the control unit 117 to the traverse motor drive unit 108. The traverse motor drive unit 108 drives the traverse motor by the transmitted movement amount (Step 710).
At the end of driving the traverse motor, the objective lens should be at the center of the housing for calculation, but it is actually difficult due to time lag, track pitch lag of the optical disk, and the like. Therefore, correction is performed. First, the control unit 117 detects a tracking error value output by the tracking actuator driving unit 107 when driving the traverse motor is stopped (step 711). As the absolute value of the tracking error increases, the objective lens shifts from the center of the housing. The calculation unit 622 calculates a correction value, and stores the calculated correction value in order to correct the movement amount at the time of the next movement amount calculation (step 709) (step 712). Returning to step 705, the process is repeated.
[0065]
ADVANTAGE OF THE INVENTION According to this invention, even if an optical disk has a flaw etc., it becomes possible to perform tracking control during recording or reproduction (at the time of tracking control) without the objective lens being biased in the housing.
This will be specifically described with reference to FIG. FIG. 9 shows the change in the tracking control amount (solid line 902) and the displacement of the objective lens in the optical pickup 102 when the scratched optical disk is reproduced by the optical disk device according to the third embodiment of the present invention (during tracking control). FIG. For comparison, broken lines 903 and 904 show changes in the tracking control amount in the conventional example. Reference numeral 901 denotes a threshold (tracking offset determination level) in the conventional example. Reference numerals 921, 922, and 923 indicate positions of the objective lens in the optical pickup.
In the periods 911 to 912, the optical disc apparatus drives the tracking actuator to move the objective lens while keeping the traverse motor 110 stopped so that the light beam spot follows the recording track. At the same time, the arithmetic unit 622 calculates the number of tracks to which the light beam spot has moved within a predetermined time at predetermined time intervals while counting the number of FG pulses detected by the rotation information detection unit 104 mounted on the spindle motor 103. I do. At predetermined time intervals (position 912), the optical disk device drives the traverse motor 110 to move the feed 109, and returns the objective lens to the center of the housing (912-913). When the objective lens returns to the center of the housing (913), the driving of the traverse motor 110 ends. Thereby, stable recording / reproducing characteristics can be obtained.
[0066]
In the conventional optical disc device, after the tracking control amount reaches the threshold (tracking offset determination level), the determination unit cannot determine the activation of the traverse motor until a certain period elapses. Therefore, a response delay as shown by a broken line 903 occurred. Since the value of the tracking error greatly fluctuates in a portion where the optical disc has a flaw, the timing at which the determination unit determines to start the traverse motor is further delayed, and a response indicated by a broken line 904 occurs.
In the optical disk device of the present invention, a response delay as shown by a broken line 903 does not occur, and even if the optical disk is damaged, it is not affected.
[0067]
<< Example 4 >>
Fourth Embodiment An optical disk device according to a fourth embodiment of the present invention will be described with reference to FIGS. The optical disc of the fourth embodiment is a CD-ROM (compact optical disc) (as described in the conventional example, any other optical disc may be used). In the CD-ROM, information is reproduced by a CLV method in which the linear velocity is constant and the rotational speed changes depending on the reproduction position on the optical disk.
[0068]
The structure of the optical disk has already been described with reference to FIG.
Next, the configuration of the optical disk device according to the fourth embodiment will be described. FIG. 6 is a block diagram showing a configuration of an optical disk device according to Embodiment 4 of the present invention. FIG. 6 has been described in the third embodiment. In the fourth embodiment, the operations of the determination unit 121 and the operation unit 622 are different from those of the third embodiment. Otherwise, Example 4 is the same as Example 3.
[0069]
In the fourth embodiment, the traverse motor is driven each time the spindle motor rotates a predetermined number of revolutions during reproduction (at the time of tracking control).
The calculation unit 622 of the fourth embodiment reads and stores the count value of the FG pulse output from the rotation information detection unit 104 every time the determination unit 121 instructs the start of the traverse motor. The calculation unit 622 according to the fourth embodiment calculates a target count value that is larger by a predetermined value (threshold) than the count value of the FG pulse at the time of the previous input of the traverse motor start command. The calculation method is the same as in the third embodiment (Equation (3)). At this time, it is preferable to add the correction value described in the first embodiment.
The configuration of the calculation unit 622 of the fourth embodiment may be the same as that of the third embodiment.
[0070]
The determination unit 121 of the fourth embodiment determines whether or not the change in the count value from when the traverse motor was driven last time to the present is equal to or greater than a predetermined threshold (whether or not the current count value is greater than the target count value). judge. If the change in the count value of the FG pulse is equal to or greater than the predetermined threshold, the determination unit 121 instructs the traverse motor to start. The control unit 118 sends a command to the traverse motor drive unit 108 to drive the traverse motor 110 by the distance calculated by the calculation unit 622. Thereby, the objective lens returns to the vicinity of the center in the housing.
In the third and fourth embodiments, the drive amount of the traverse motor 110 for one time from the inner circumference to the outer circumference of the optical disk of the CAV system, the CLV system, or the like is substantially constant.
[0071]
FIG. 10 is a flowchart illustrating a control method of the optical disc apparatus (control method of the traverse motor during reproduction (at the time of tracking control)) according to the fourth embodiment of the present invention.
At the time of reproduction, first, the rotation information detection unit 104 starts a counter of the rotation pulse of the spindle motor (step 1001). The calculation unit 622 detects and stores the current count value R (i) (count value of the starting point) output by the rotation information detection unit 104 (Step 1002). Further, the calculation unit 622 detects a new current count value R (j) output from the rotation information detection unit 104 (Step 1003). The arithmetic unit 622 checks whether or not the difference between the count values R (j) and R (i) is larger than a threshold (step 1004). While the difference between the count values R (j) and R (i) is smaller than the threshold value, the process returns to step 1003 to repeat the processing.
If the difference between the count values R (j) and R (i) is equal to or greater than the threshold value, the calculation unit 622 calculates the movement amount from the count values R (i) and R (j) (step 1005). At this time, the calculation unit 622 adds a correction value described later. The movement amount calculated by the calculation unit 622 is transmitted from the control unit 117 to the traverse motor drive unit 108. The traverse motor drive unit 108 drives the traverse motor by the transmitted movement amount (step 1006). Arithmetic unit 622 sets count value R (j) to count value R (i) (step 1007).
At the end of driving the traverse motor, the objective lens should be at the center of the housing for calculation, but it is actually difficult due to time lag, track pitch lag of the optical disk, and the like. Therefore, correction is performed. First, the control unit 117 detects the driving amount of the tracking actuator output by the tracking actuator driving unit 107 when the traverse motor is stopped (step 1008). As the driving amount of the tracking actuator increases, the objective lens shifts from the center of the housing. The calculation unit 622 calculates a correction value and stores the calculated correction value in order to correct the movement amount at the time of the next movement amount calculation (step 1005) (step 1009). Returning to step 1003, the process is repeated.
[0072]
The optical disc device and the control method of the fourth embodiment have the same effects as the third embodiment. Even if the optical disc has a flaw, the control of the traverse motor is not affected by the flaw.
In the present embodiment, the optical pickup 102 is caused to follow the track 302, and when the change in the count value of the FG pulse reaches a predetermined value (threshold), the optical disk device drives the traverse motor 110. For example, by setting the threshold value to a count value for 10 rotations of the spindle motor, the objective lens is not deviated by more than 10 tracks in the housing, and more stable tracking control can be performed.
[0073]
Although the CD-ROM of the embodiment is a CLV type optical disk (sector length is constant and the start and end of each sector are not aligned in the radial direction), the present invention is applicable to a CAV type or ZCAV type optical disk. It goes without saying that the invention can be applied. In many CAV or ZCAV optical discs, the address of each sector has radial position information and angular position information. In such a case, the radial distance between the two positions can be easily obtained by calculating the difference between the radial position information of each address.
[0074]
【The invention's effect】
Advantageous Effects of Invention According to the present invention, an optical disk device that determines the optimal start timing of a traverse motor without delay even if the optical disk has a flaw or the like without delay and exhibits stable recording / reproducing characteristics and a control method thereof are realized. The advantageous effect that can be obtained is obtained.
According to the present invention, there is obtained an advantageous effect that an optical disk device having an objective lens stably positioned within a predetermined range near the center in a housing and an optical pickup having a high followability and a control method thereof can be realized.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a configuration of an optical disc device according to first and second embodiments of the present invention.
FIG. 2 is a flowchart showing a control method of the optical disc apparatus according to the first embodiment of the present invention (a method of controlling a traverse motor during reproduction (at the time of tracking control));
FIG. 3 is a plan view of an optical disc according to Embodiments 1, 2, 3, and 4 of the present invention.
FIG. 4 is a diagram showing a change in a tracking control amount and a displacement of an objective lens position in an optical pickup when an optical disk having a scratch is reproduced by the optical disk apparatus according to the first embodiment of the present invention (during tracking control).
FIG. 5 is a flowchart showing a control method of the optical disc apparatus according to the second embodiment of the present invention (a control method of a traverse motor during reproduction (at the time of tracking control)).
FIG. 6 is a block diagram illustrating a configuration of an optical disc device according to Embodiments 3 and 4 of the present invention.
FIG. 7 is a flowchart showing a control method of the optical disc apparatus according to the third embodiment of the present invention (a traverse motor control method during reproduction (at the time of tracking control));
FIG. 8 is a diagram showing an FG waveform of the optical disc device according to the third embodiment of the present invention.
FIG. 9 is a diagram showing a change in a tracking control amount and a displacement of the position of an objective lens in an optical pickup when an optical disk having a scratch is reproduced by the optical disk device according to the third embodiment of the present invention (during tracking control).
FIG. 10 is a flowchart illustrating a control method of the optical disc apparatus according to the fourth embodiment of the present invention (a control method of the traverse motor during reproduction (at the time of tracking control)).
FIG. 11 is a block diagram showing a configuration of a conventional optical disk device.
FIG. 12 is a flowchart showing a control method of a conventional optical disc apparatus (a control method of a traverse motor at the time of recording or reproduction (at the time of tracking control)).
FIG. 13 is a diagram showing a change in a tracking control amount when an optical disc is recorded or reproduced (at the time of tracking control) in a conventional optical disc apparatus, and a displacement of an objective lens in an optical pickup.
FIG. 14 is a plan view of a conventional optical disc (with defects).
FIG. 15 is a diagram showing a change in a tracking control amount and a shift in the position of an objective lens in an optical pickup when recording or reproducing an optical disk having a scratch in a conventional optical disk device (at the time of tracking control).
[Explanation of symbols]
101, 1401 Optical disk
102 Optical Pickup
103 spindle motor
104 rotation information detector
105 Spindle motor driver
106 Focus actuator drive unit
107 Tracking actuator driver
108 Traverse motor drive
109 feeds
110 traverse motor
111 playback unit
112 decoder
113 Input / output unit
114 Position information detector
115 Tracking error detector
116 Focus Error Detector
117 control unit
118 Host PC
121, 1211 judgment unit
122, 622 arithmetic unit
302, 1402 tracks
303 sectors
304 Address = 0
305 Measurement start address
306 Measurement end address
401, 901, 1301, 1501 Tracking offset judgment level
421, 422, 423 Position of Objective Lens in Optical Pickup
801 FG waveform
802 Number of FG waveform pulses within a predetermined time
803 Number of pulses of FG waveform during one rotation
921, 922, 923 Position of objective lens in optical pickup
1321, 1323, 1324 Position of the objective lens in the optical pickup
1403 defect
1521, 1523, 1524 Position of objective lens in optical pickup

Claims (12)

An objective lens for imaging a light beam spot on an optical disc;
A tracking actuator that drives the objective lens in a width direction of a recording track of the optical disc;
A traverse motor that drives the optical pickup including the objective lens in a radial direction of the optical disc;
Position information detecting means for detecting position information recorded on the optical disc,
Calculating means for calculating the amount of movement of the light beam spot in the radial direction of the optical disc using the position information;
Has,
An optical disk device, wherein the moving amount of the light beam spot is calculated by the calculating means at predetermined time intervals, and the traverse motor is driven to move the optical pickup by the same amount as the moving amount. An objective lens for imaging a light beam spot on an optical disc;
A tracking actuator that drives the objective lens in a width direction of a recording track of the optical disc;
A traverse motor that drives the optical pickup including the objective lens in a radial direction of the optical disc;
Position information detecting means for detecting position information recorded on the optical disc,
Calculating means for calculating the amount of movement of the light beam spot in the radial direction of the optical disc using the position information;
Has,
An optical disk device, wherein the traverse motor is driven to move the optical pickup by the same amount as the movement amount of the light beam spot every time the movement amount reaches a predetermined amount. A spindle motor for rotating an optical disc;
An objective lens for imaging a light beam spot on the optical disc;
A tracking actuator that drives the objective lens in a width direction of a recording track of the optical disc;
A traverse motor that drives the optical pickup including the objective lens in a radial direction of the optical disc;
Rotation information detection means for detecting the rotation of the spindle motor,
An arithmetic unit for calculating the amount of movement of the optical beam spot in the radial direction of the optical disk using the rotation information,
Has,
An optical disk device, wherein the moving amount of the light beam spot is calculated by the calculating means at predetermined time intervals, and the traverse motor is driven to move the optical pickup by the same amount as the moving amount. A spindle motor for rotating an optical disc;
An objective lens for imaging a light beam spot on the optical disc;
A tracking actuator that drives the objective lens in a width direction of a recording track of the optical disc;
A traverse motor that drives the optical pickup including the objective lens in a radial direction of the optical disc;
Rotation information detection means for detecting the rotation of the spindle motor,
An arithmetic unit for calculating the amount of movement of the optical beam spot in the radial direction of the optical disk using the rotation information,
Has,
Each time the rotation amount of the spindle motor reaches a predetermined amount or the amount of movement of the light beam spot reaches a predetermined amount, the traverse motor is driven to move the optical pickup by the same amount as the movement amount. An optical disc device characterized by causing the The arithmetic means has a counter and an arithmetic processing unit (hereinafter, referred to as “CPU”),
The counter detects the number of rotations of the spindle motor by inputting an output signal of the rotation information detection unit as a clock signal and counting the number of rotations.
The CPU calculates an amount of movement of the optical beam spot in a radial direction of the optical disk based on the number of rotations,
The optical disk device according to claim 3 or 4, wherein: The arithmetic means is a CPU having an external interrupt terminal,
The CPU inputs an output signal of the rotation information detecting means to an external interrupt terminal, counts the number of interrupts to the external interrupt terminal, and moves the light beam spot in the radial direction of the optical disc based on the number of interrupts. Calculating the amount of movement
The optical disk device according to claim 3 or 4, wherein: When the traverse motor is driven to move the optical pickup by the same amount as the movement amount, a value of a tracking error or a drive amount of the tracking actuator is detected, and the value of the tracking error or the If the driving amount of the tracking actuator exceeds a certain range, the value of the tracking error or the driving amount of the tracking actuator at the time when the driving of the traverse motor is completed during the next driving of the traverse motor is constant. 5. The optical disk device according to claim 1, wherein an amount of movement of the optical pickup by the traverse motor is corrected so as to fall within a range of the optical disk device. 6. An objective lens for imaging a light beam spot on an optical disc;
A tracking actuator that drives the objective lens in a width direction of a recording track of the optical disc;
A traverse motor that drives the optical pickup including the objective lens in a radial direction of the optical disc;
A method for controlling an optical disc device having
A calculating step of detecting position information recorded on the optical disc and calculating a moving amount of the light beam spot using the position information at predetermined time intervals;
A moving step of driving the traverse motor to move the optical pickup by an amount equal to the moving amount thereof at predetermined time intervals;
A method for controlling an optical disk device, comprising: An objective lens for imaging a light beam spot on an optical disc;
A tracking actuator that drives the objective lens in a width direction of a recording track of the optical disc;
A traverse motor that drives the optical pickup including the objective lens in a radial direction of the optical disc;
A method for controlling an optical disc device having
A detecting step of detecting position information recorded on the optical disc, and calculating a movement amount of the light beam spot moved in a radial direction of the optical disc using the position information;
A moving step of driving the traverse motor to move the optical pickup by the same amount as the moving amount each time the moving amount reaches a predetermined amount;
A method for controlling an optical disk device, comprising: A spindle motor for rotating an optical disc;
An objective lens for imaging a light beam spot on the optical disc;
A tracking actuator that drives the objective lens in a width direction of a recording track of the optical disc;
A traverse motor that drives the optical pickup including the objective lens in a radial direction of the optical disc;
A method for controlling an optical disc device having
A calculating step of detecting rotation of the spindle motor and calculating a movement amount of the light beam spot moved in a radial direction of the optical disc using the rotation information at predetermined time intervals;
A moving step of driving the traverse motor to move the optical pickup by an amount equal to the moving amount thereof at predetermined time intervals;
A method for controlling an optical disk device, comprising: A spindle motor for rotating an optical disc;
An objective lens for imaging a light beam spot on the optical disc;
A tracking actuator that drives the objective lens in a width direction of a recording track of the optical disc;
A traverse motor that drives the optical pickup including the objective lens in a radial direction of the optical disc;
A method for controlling an optical disc device having
A calculating step of detecting rotation of the spindle motor and calculating an amount of movement of the optical beam spot in a radial direction of the optical disk using the rotation information;
A moving step of driving the traverse motor to move the optical pickup by the same amount as the amount of rotation every time the amount of rotation of the spindle motor becomes a predetermined amount or the amount of movement becomes a predetermined amount;
A method for controlling an optical disk device, comprising: When the traverse motor is driven and the optical pickup is moved by the same amount as the amount of movement, the value of the tracking error or the amount of drive of the tracking actuator is detected, and the value of the tracking error or the If the driving amount of the tracking actuator exceeds a certain range, the value of the tracking error or the driving amount of the tracking actuator at the time when the driving of the traverse motor is completed during the next driving of the traverse motor is constant. The control method of an optical disk device according to claim 8, further comprising a correction step of correcting a movement amount of the optical pickup by the traverse motor so as to fall within a range of:

Images