JP3855755B2

JP3855755B2 - Optical information recording / reproducing apparatus and recording light intensity learning method

Info

Publication number: JP3855755B2
Application number: JP2001373685A
Authority: JP
Inventors: 正春井村; 巧松浦; 勤甲斐
Original assignee: Panasonic Corp; Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Corp; Panasonic Holdings Corp
Priority date: 2001-12-07
Filing date: 2001-12-07
Publication date: 2006-12-13
Anticipated expiration: 2021-12-07
Also published as: JP2003173560A

Description

【０００１】
【発明の属する技術分野】
本発明は光学的記録媒体に情報を記録する光学的情報記録再生装置および記録光強度学習方法に関する。
【０００２】
【従来の技術】
従来、光学的記録媒体として、ＣＤＲｅｗｒｉｔａｂｌｅ媒体やＤＶＤＲｅ−ｒｅｃｏｒｄａｂｌｅ媒体があり、これらの媒体に情報を記録する光学的情報記録再生装置および記録光強度学習方法は、たとえば「ＤＶＤＳｐｅｃｉｆｉｃａｔｉｏｎｆｏｒＲｅ−ｒｅｃｏｒｄａｂｌｅＤｉｓｃＰａｒｔ１ＰＨＹＳＩＣＡＬＳＰＥＣＩＦＩＣＡＴＩＯＮＳ」に記載されたものが知られている。
【０００３】
図９は従来の光学的情報記録再生装置の一例であるＤＶＤＲｅ−ｒｅｃｏｒｄａｂｌｅの構造を示しており、光学的記録媒体（ＤＶＤ−ＲＷ媒体）である光ディスク１、前記光ディスク１に光ビームを照射するレーザダイオード(以下、ＬＤ（ＬａｓｅｒＤｉｏｄｅ）と記す）を搭載しているピック２、前記ピック２内のＬＤを駆動するレーザ駆動回路３、前記レーザ駆動回路３に対し所望のレーザ出力を指令するレーザ出力制御回路４、前記光ディスク１上に記録されている初期記録情報を読み出す初期記録情報読み込み回路６、読み出された初期記録情報をもとに記録パワーを可変する記録パワー可変回路１２、前記光ディスク１上に記録された記録パターンから再生信号の変調度を検出する変調度検出回路７、前記変調度検出回路７から検出された変調度と記録パワーから記録パワーで正規化された変調度を演算する正規化変調係数演算回路８、正規化変調係数と初期記録情報から前記光ディスク１と前記ピック２との組み合わせにおける最適記録パワーを求める最適記録パワー演算回路１３、前記光ディスク１に記録する情報記録パターンを発生する記録パターン発生回路１１から構成されている。
【０００４】
光ディスク１上には図１０に示すごとく情報を記録するデータ領域２１以外に光ディスク１の内周部に情報を記録する場合必要に応じて記録パワーを学習する記録パワー学習領域２２が設けられている。
【０００５】
光学的情報記録再生装置が記録パワー学習を行う場合、まず光ディスク１上に記録されている初期記録情報である推奨記録パワーＰｉ等を初期記録情報読み込み回路６により読み込む。この推奨記録パワーＰｉは光ディスク毎に標準評価機等による一定条件のもとで決定された最適な記録パワーである。実際に情報を記録する場合には、記録時の温度状態によるＬＤ波長変化にともなう記録媒体の光感度変化やピック２の埃等によるレーザ伝送効率の低下等により最適記録パワーが異なるため、前記記録パワー学習領域２２で記録時の状態に応じた記録パワーを学習する必要がある。また、各光学的情報記録再生装置は光ディスク毎に最適パワー制御係数として、最適記録パワーを得るための増倍率ρ（以下、最適パワー増倍率ρ）、目標正規化変調係数γｔａｒｇｅｔ（以下、γｔと記す）を保持している。
【０００６】
次に光ピック２を光ディスク１の内周部に設けられた記録パワー学習領域２２に移動させ、記録パターン発生回路１１から記録パワー学習用パターンとしてたとえばランダムな８−１６エンコードデータパターンを発生させるとともに記録パワー可変回路１２は、前記推奨記録パワーＰｉを最適パワー増倍率ρで割った値より小さな記録パワーをパワー学習開始記録パワーＰｗ０とし、図１１に示すごとくパワー学習記録パワーを一定パワーづつ増加させ、１０段階の記録パワー（Ｐｗ０〜Ｐｗ９）で記録パワー学習用パターンを前記記録パワー学習領域２２内に記録する。
【０００７】
変調度検出時には、ピック２からは各記録パワーＰｗに応じた再生波形が再生され、変調度検出回路７により各記録パワーでの変調度（ｍ０〜ｍ９）が検出される。
【０００８】
図１２に一定の記録パワーで記録パワー学習用パターンが記録された場合の再生波形を示す。記録パワー学習用パターンは情報を記録する場合と同じ８−１６エンコードデータパターンで記録されているため記録単位時間Ｔ基準で３Ｔ〜１１Ｔおよび１４Ｔの記録長マーク（以後、マークと記す）と未記録長スペース（以後、スペースと記す）からなる。
【０００９】
変調度検出回路７は、最長スペースである１４Ｔスペース、最長マークである１４Ｔマークのそれぞれの振幅値ＡＨ１、ＡＬ１から数１を用いて変調度ｍを算出する。
【００１０】
【数１】

【００１１】
変調度検出回路７は、前記記録パワーと検出した変調度ｍから図１３のごとく各記録パワーと変調度ｍの関係を求める。
【００１２】
正規化変調係数演算回路８は前記記録パワーと変調度の関係から数２を用いて図１３に示すごとく各記録パワーと正規化変調係数γの関係を算出する。
【００１３】
【数２】

【００１４】
たとえば、記録パワーＰｗ０とＰｗ１の変調度ｍ０、ｍ１から、数３、数４を用いて記録パワーＰｗ０１での正規化変調係数γ１が算出できる。
【００１５】
【数３】

【００１６】
【数４】

【００１７】
次に最適記録パワー演算回路１３は前記各記録パワーと正規化変調係数γの関係から目標正規化変調係数γｔを実現する記録パワーである目標記録パワーＰｔを求め、数５を用いて最適記録パワーＰｏを算出し、情報記録パワーとする。
【００１８】
【数５】

【００１９】
情報をデータ領域２１に記録する場合は、前記記録パワー学習を行って決定された情報記録パワーになるようレーザ出力制御回路４が動作し、パワー学習状態での最適記録パワーで情報が記録される。
【００２０】
【発明が解決しようとする課題】
この光学的情報記録再生装置においては、光ディスク上に記録されている推奨記録パワーＰｉや事前に求めた光ディスク毎の増倍率ρ、目標正規化変調係数γｔをもとに最適記録パワーを求めるため、標準評価機による一定条件下のもとでの最適記録パワーが求まる。しかしながら実際の装置においてはチルト等の機械的なずれやデフォーカス等の制御誤差など実効記録パワーが減少する要因があり、実際に情報を記録する情報記録パワーを最適記録パワーより高めに設定する必要がある。
【００２１】
また、光学的記録媒体は一般的に最適記録パワーより高い記録パワーで何度も記録を繰り返すと記録トラック溝を劣化させ記録トラック溝と光ビームとの相対位置情報であるトラッキング誤差信号振幅が減少し、最悪の場合トラッキング制御が不能になるという場合が発生する。
【００２２】
本発明は、情報記録パワーを高めに設定してもトラッキング制御が不能にならないよう記録パワーを決定する記録パワー学習を実現することを目的とする。
【００２３】
【課題を解決するための手段】
この課題を解決するために、本発明の光学的情報記録再生装置は、記録トラック溝が一定の周期で径方向に変動してなる光学的記録媒体と、前記光学的記録媒体に光ビームを照射する光照射手段と、前記光照射手段に対し所望の光強度で発光させる光駆動手段と、前記光学的記録媒体内の光強度学習領域に光強度学習開始光強度（Ｐｗ０）および所望の光強度（Ｐｗｎ）で光強度学習パターンを記録するよう制御する記録出力制御手段と、初期記録情報として予め光学的情報記録再生装置に保持されているトラック溝変動信号限界振幅比（δｔ）を読み込む初期記録情報読み込み手段と、前記光強度学習パターンの再生信号の振幅から変調度を検出する変調度検出手段と、前記記録トラック溝の周期的な変動により発生するトラック溝変動信号の振幅を検出するトラック溝変動信号振幅検出手段と、前記光強度学習領域に複数の光強度で記録された記録領域の変調度より前記光学的記録媒体に記録する下限光強度を演算する光強度下限演算手段と、前記光強度学習領域に記録された記録領域のトラック溝変動信号振幅より前記光学的記録媒体に記録する上限光強度を演算する光強度上限演算手段と、前記下限光強度と前記上限光強度より前記光学的記録媒体に情報を記録する光強度を決定する情報記録光強度決定手段とを備え、前記光強度上限演算手段が、前記所望の光強度（Ｐｗｎ）で記録した前記記録領域のトラック溝変動信号振幅（ｗｎ）を前記光強度学習開始光強度（Ｐｗ０）で記録した記録領域のトラック溝変動信号振幅（ｗ０）で除算（ｗｎ／ｗ０）して前記光強度（Ｐｗｎ）でのトラック溝変動信号振幅比（δｎ）を算出する手段と、前記トラック溝変動信号振幅比（δｎ）と前記トラック溝変動信号限界振幅比（δｔ）との大小を比較する手段と、前記トラック溝変動信号振幅比（δｎ）が前記トラック溝変動信号限界振幅比（δｔ）以下になった場合、前記光強度（Ｐｗｎ）を上限光強度と判断する手段とからなるものである。
【００２４】
また、本発明の他の光学的情報記録再生装置は、記録トラック溝を有する光学的記録媒体に光ビームを照射する光照射手段と、前記光照射手段に対し所望の光強度で発光させる光駆動手段と、前記光学的記録媒体内の光強度学習領域に光強度学習開始光強度（Ｐｗ０）および所望の光強度（Ｐｗｎ）で光強度学習パターンを記録するよう制御する記録出力制御手段と、初期記録情報として予め光学的情報記録再生装置に保持されているトラッキング誤差信号限界振幅比（τｔ）を読み込む初期記録情報読み込み手段と、前記光強度学習パターンの再生信号の振幅から変調度を検出する変調振幅検出手段と、トラッキング制御を切った状態で前記記録トラック溝を横切るように前記光ビームを移動させてトラッキング誤差信号を検出するトラッキング誤差信号検出手段と、前記光強度学習領域に複数の光強度で記録された記録領域の変調度より前記光学的記録媒体に記録する下限光強度を演算する光強度下限演算手段と、前記光強度学習領域に記録された記録領域のトラッキング誤差信号振幅より前記光学的記録媒体に記録する上限光強度を演算する光強度上限演算手段と、前記下限光強度と前記上限光強度より前記光学的記録媒体に情報を記録する光強度を決定する情報記録光強度決定手段とを備え、前記光強度上限演算手段が、前記所望の光強度（Ｐｗｎ）で記録した前記記録領域のトラッキング誤差信号振幅（ＴＥｎ）を前記光強度学習開始光強度（Ｐｗ０）で記録した前記記録領域のトラッキング誤差信号振幅（ＴＥ０）で除算（ＴＥｎ／ＴＥ０）して前記光強度（Ｐｗｎ）でのトラッキング誤差信号振幅比（τｎ）を算出する手段と、前記トラッキング誤差信号振幅比（τｎ）と前記トラッキング誤差信号限界振幅比（τｔ）との大小を比較する手段と、前記トラッキング誤差信号振幅比（τｎ）が前記トラッキング誤差信号限界振幅比（τｔ）以下になった場合、前記光強度（Ｐｗｎ）を前記上限光強度とする手段とからなるものである。
【００２５】
【発明の実施の形態】
以下、本発明の実施の形態について、図１から図８を用いて説明する。
【００２６】
（実施の形態１）
図１は本発明の光学的情報記録再生装置の一実施の形態を示し、図１において１は光学的記録媒体である光ディスクで、情報を記録する記録トラック溝が形成されており、また記録トラック溝には図３に示すような記録クロックを生成するために径方向に一定周期で変動してなるウォブルトラック１９が形成されている。
【００２７】
２は光照射手段で前記光ディスク１に光ビームを照射するＬＤを搭載しているピック、５は光駆動手段でＬＤを駆動するレーザ駆動回路３とレーザ出力制御回路４からなる。
【００２８】
６は前記光ディスク１上に記録されている初期記録情報を読み出す初期記録情報読み込み回路、７は変調度検出手段で再生信号の振幅から変調度を検出する変調度検出回路、１０は光強度下限演算手段で前記変調度検出回路７から検出された変調度と記録パワーから記録パワーで正規化された変調度を演算する正規化変調係数演算回路８と正規化変調係数をもとに情報を記録する下限光強度を演算する下限記録パワー演算回路９からなり、１２は記録出力制御手段で初期記録情報の推奨記録パワーと記録パワー増分から記録パワー学習に使用する記録パワーを制御する記録パワー可変回路、１４はウォブルトラックにより発生するトラック溝変動信号（以下、ウォブル信号と記す）の振幅を検出するトラック溝変動信号振幅検出手段であるウォブル信号振幅検出回路、１５は記録パワーによるウォブル信号振幅の減少量をもとに前記光学的記録媒体に記録する上限光強度を演算する光強度上限演算手段である上限記録パワー演算回路、１６は前記下限記録パワーと上限記録パワーをもとに情報を記録する光強度を決定する情報記録光強度決定手段である情報記録パワー決定回路である。
【００２９】
また図２は本発明の記録光強度学習方法の一実施の形態を示すものである。
【００３０】
以上のように構成された本発明の光学的情報記録再生装置および本発明の記録光強度学習（以下、記録パワー学習と記す）方法について図１〜図５を用いて説明する。
【００３１】
光学的情報記録再生装置が記録パワー学習を行う場合、まず光ディスク１上に記録されている初期記録情報である推奨記録パワーＰｉ等を初期記録情報読み込み回路６により読み込む。また、各光学的情報記録再生装置が保持している光ディスク毎の記録情報である下限記録パワーを得るための増倍率ρｍ（以下、下限記録パワー増倍率ρｍ）および下限正規化変調係数γｍ、上限記録パワーを得るためのウォブル信号限界振幅比δｔ、記録パワー学習時に記録パワーを増加させる量である記録パワー増分Ｐｄを取り込む。
【００３２】
従来の技術で述べた最適記録パワー増倍率ρ、目標正規化変調係数γｔは、標準評価機等での一定条件下での値であるが、本発明の光学的記録再生装置および光強度学習方法の下限記録パワー増倍率ρｍ、下限正規化変調係数γｍが最適記録パワー増倍率ρ、目標正規化変調係数γｔと同等となる場合もある。
【００３３】
次に光ピック２を光ディスク１の内周部に設けられた記録パワー学習領域２２に移動させ、記録パターン発生回路１１から記録パワー学習用パターンとしてたとえばランダムな８−１６エンコードデータパターンを発生させるとともに記録パワー可変回路１２は、前記下限記録パワーＰｉを下限パワー増倍率ρｍで割った値より小さな記録パワーをパワー学習開始記録パワーＰｗ０とし記録パワー学習用パターンを前記記録パワー学習領域２２内に記録する。
【００３４】
記録パワー学習用パターン再生時には、変調度検出回路７により記録パワーＰｗ０での変調度ｍ０を検出するとともに、ウォブル信号振幅検出回路１４によりウォブル信号振幅ｗ０を検出する。
【００３５】
図３に示すようにウォブルトラック１９上に沿って光ビーム２０が通過すると、図４に示すようなウォブル信号が検出される。ＤＶＤ−ＲＷ媒体の場合、このウォブル信号の周波数は標準速度で約１４０ＫＨｚで検出することができる。
【００３６】
上限記録パワー演算回路１５は、数６を用いて記録パワーＰｗ時のウォブル信号振幅ｗからウォブル信号振幅比δを算出する。
【００３７】
【数６】

【００３８】
したがって、パワー学習開始記録パワーＰｗ０でのウォブル信号振幅比δ０は１である。また、上限記録パワー演算回路１５はウォブル信号振幅比δとウォブル信号限界振幅比δｔを比較し、ウォブル信号振幅比δがウォブル信号限界振幅比δｔより大きい場合は、記録パワー可変回路１２に、記録パワーＰｗを記録パワー増分Ｐｄだけ増すよう指令する。
【００３９】
記録パワー可変回路１２によりパワー学習開始記録パワーＰｗ０から記録パワー増分Ｐｄだけ記録パワーが増加した記録パワーＰｗ１により、再び記録パワー学習領域に記録パワー学習用パターンが記録され、変調度ｍ１とウォブル信号ｗ１が検出される。
【００４０】
正規化変調係数演算回路８は数３を用いて記録パワーＰｗ０１に応じた正規化変調係数γ１を算出する。
【００４１】
上限記録パワー演算回路１５は、数６を用いて記録パワーＰｗ１でのウォブル信号振幅ｗ１からｗ０を基準にウォブル信号振幅比δ１を算出する。また、上限記録パワー演算回路１５はウォブル信号振幅比δ１とウォブル信号限界振幅比δｔを比較し、ウォブル信号振幅比δ１がウォブル信号限界振幅比δｔより大きい場合は、記録パワー可変回路１２に、記録パワーＰｗ１を記録パワー増分Ｐｄだけ増すよう指令する。
【００４２】
このように、記録パワーを増加させるごとに、記録パワー学習領域に記録パワー学習用パターンを記録し、変調度ｍとウォブル信号振幅ｗを検出し、正規化変調係数γ、ウォブル信号振幅比δを求め、ウォブル信号限界振幅比δｔと比較する。
【００４３】
記録パワーＰｗｎで記録した場合のウォブル信号振幅比δｎがウォブル信号限界振幅比δｔ以下となった場合は、上限記録パワーＰｗｍａｘをＰｗｎとし、記録パワー学習領域への記録を終了する。
【００４４】
下限記録パワー演算回路９は、記録パワーと正規化変調係数γから下限正規化変調係数γｍに対応する記録パワーＰｍを求め、Ｐｍに下限記録パワー増倍率ρｍをかけた値を下限記録パワーＰｗｍｉｎとする。情報記録パワー決定回路１６は前記下限記録パワーＰｗｍｉｎと前記上限記録パワーＰｗｍａｘの間の記録パワーを情報を記録する情報記録パワーＰ０と設定する。
【００４５】
情報記録パワーＰ０は、たとえば、下限記録パワーＰｗｍｉｎに事前にチルト残差やサーボ制御誤差による記録パワー減少分を測定しておき、その記録パワーを加えた記録パワーと前記上限記録パワーＰｗｍａｘとを比較し、小さな値の記録パワーを情報記録パワーＰ０として決定する方法がある。
【００４６】
実際に情報をデータ領域に記録する場合、情報記録パワー決定回路１６は記録パワー学習により決定された情報記録パワーＰ０となるようレーザ出力制御回路４に指令を行い、適正な記録パワーで情報を記録することが可能となる。
【００４７】
なお、以上の説明では変調度の検出および正規化変調係数の算出を所定の記録パワーで記録後毎に行っていたが、記録パワーごとに学習パターンを異なる領域に記録するのであれば変調度の検出および正規化変調係数の算出は上限記録パワー決定後に一括して行っても同様な結果になることは言うまでもない。
【００４８】
（実施の形態２）
図６は本発明の光学的情報記録再生装置の一実施の形態を示し、図６において実施の形態１と異なるのはトラッキング誤差信号振幅検出回路１７およびトラッキング誤差信号振幅検出回路１７で検出されたトラッキング誤差信号振幅から上限記録パワーを求める上限記録パワー演算回路１８である。
【００４９】
また図７は本発明の記録光強度学習方法の一実施の形態を示すものである。
【００５０】
以上のように構成された本発明の光学的情報記録再生装置および本発明の記録光強度学習方法について図６〜図８を用いて説明する。
【００５１】
光学的情報記録再生装置が記録パワー学習を行う場合、まず光ディスク１上に記録されている初期記録情報である推奨記録パワーＰｉ等を初期記録情報読み込み回路６により読み込む。また、各光学的情報記録再生装置が保持している光ディスク毎の記録情報である下限記録パワー増倍率ρｍ、下限正規化変調係数γｍ、トラッキング誤差信号限界振幅比τｔ、記録パワー増分Ｐｄを取り込む。
【００５２】
次に光ピック２を光ディスク１の内周部に設けられた記録パワー学習領域２２に移動させ、記録パターン発生回路１１から記録パワー学習用パターンとしてたとえばランダムな８−１６エンコードデータパターンを発生させるとともに記録パワー可変回路１２は、前記下限記録パワーＰｉを下限パワー増倍率ρｍで割った値より小さな記録パワーをパワー学習開始記録パワーＰｗ０とし記録パワー学習用パターンを前記記録パワー学習領域内に記録する。
【００５３】
記録パワー学習用パターン再生時には、変調度検出回路７により記録パワーＰｗ０での変調度ｍ０を検出する。
【００５４】
次にトラッキング制御を切り、光ビームを記録パワーＰｗ０で記録した記録トラック溝を横切るよう移動させ、そのときのトラッキング誤差信号振幅検出回路１７によりトラッキング誤差信号振幅ＴＥ０を検出する。
【００５５】
上限記録パワー演算回路１８は、数７を用いて記録パワーＰｗ時のトラッキング誤差信号振幅ＴＥからトラッキング誤差信号振幅比τを算出する。
【００５６】
【数７】

【００５７】
したがって、パワー学習開始記録パワーＰｗ０でのトラッキング誤差信号振幅比τ０は１である。また、上限記録パワー演算回路１８はトラッキング誤差信号振幅比τとトラッキング誤差信号限界振幅比τｔを比較し、トラッキング誤差信号振幅比τがトラッキング誤差信号限界振幅比τｔより大きい場合は、記録パワー可変回路１２に、記録パワーＰｗを記録パワー増分Ｐｄだけ増すよう指令する。
【００５８】
記録パワー可変回路１２によりパワー学習開始記録パワーＰｗ０から記録パワー増分Ｐｄだけ記録パワーが増加した記録パワーＰｗ１により、再び記録パワー学習領域に記録パワー学習用パターンが記録され、変調度ｍ１とウォブル信号ＴＥ１が検出される。
【００５９】
正規化変調係数演算回路８は数３を用いて記録パワーＰｗ０１に応じた正規化変調係数γ１を算出する。
【００６０】
上限記録パワー演算回路１８は、数７を用いて記録パワーＰｗ１でのトラッキング誤差信号振幅ＴＥ１からＴＥ０を基準にトラッキング誤差信号振幅比τ１を算出する。また、上限記録パワー演算回路１８はトラッキング誤差信号振幅比τ１とトラッキング誤差信号限界振幅比τｔを比較し、トラッキング誤差信号振幅比τ１がトラッキング誤差信号限界振幅比τｔより大きい場合は、記録パワー可変回路１２に、記録パワーＰｗ１を記録パワー増分Ｐｄだけ増すよう指令する。
【００６１】
このように、記録パワーを増加させるごとに、記録パワー学習領域に記録パワー学習用パターンを記録し、変調度ｍとトラッキング誤差信号振幅ＴＥを検出し、正規化変調係数γ、トラッキング誤差信号振幅比τを求め、トラッキング誤差信号限界振幅比τｔと比較する。
【００６２】
記録パワーＰｗｎで記録した場合のトラッキング誤差信号振幅比τｎがトラッキング誤差信号限界振幅比τｔ以下となった場合は、上限記録パワーＰｗｍａｘをＰｗｎとし、記録パワー学習領域への記録を終了する。
【００６３】
下限記録パワー演算回路９は、記録パワーと正規化変調係数γから下限正規化変調係数γｍに対応する記録パワーＰｍを求め、Ｐｍに下限記録パワー増倍率ρｍをかけた値を下限記録パワーＰｗｍｉｎとする。
【００６４】
情報記録パワー決定回路１６は、前記下限記録パワーＰｗｍｉｎと前記上限記録パワーＰｗｍａｘの間の記録パワーを情報を記録する情報記録パワーＰ０と設定する。
【００６５】
情報記録パワーＰ０は、たとえば、下限記録パワーＰｗｍｉｎに事前にチルト残差やサーボ制御誤差による記録パワー減少分を測定しておき、その記録パワーを加えた記録パワーと前記上限記録パワーＰｗｍａｘとを比較し、小さな値の記録パワーを情報記録パワーＰ０として決定する方法がある。
【００６６】
実際に情報をデータ領域に記録する場合、情報記録パワー決定回路１６は記録パワー学習により決定された情報記録パワーＰ０となるようレーザ出力制御回路４に指令を行い、適正な記録パワーで情報を記録することが可能となる。
【００６７】
なお、以上の説明では変調度の検出および正規化変調係数の算出を所定の記録パワーで記録後毎に行っていたが、記録パワーごとに学習パターンを異なる領域に記録するのであれば変調度の検出および正規化変調係数の算出は上限記録パワー決定後に一括して行っても同様な結果になることは言うまでもない。
【００６８】
【発明の効果】
以上のように本発明によれば、情報を記録する情報記録パワーを決定する記録光強度学習において下限記録パワーと上限記録パワーを求め、その間で記録パワーを決定するため、記録パワーが大きすぎて重ね書き記録を何度か行うことによる記録トラック溝の劣化が起こるということがなく、つねに、情報記録時の記録パワーを適正化できるという効果が得られる。
【図面の簡単な説明】
【図１】本発明の実施の形態１による光学的情報記録再生装置を示すブロック図
【図２】本発明の実施の形態１による記録光強度学習方法の説明図
【図３】光ディスク上の記録トラック溝の周期的変動を示す説明図
【図４】光ディスク上の記録トラック溝の周期的変動により検出されるウォブル信号を示す説明図
【図５】本発明の実施の形態１によるウォブル信号振幅比および正規化変調係数と記録パワーとの関係を示す説明図
【図６】本発明の実施の形態２による光学的情報記録再生装置を示すブロック図
【図７】本発明の実施の形態２による記録光強度学習方法の説明図
【図８】本発明の実施の形態２によるトラッキング誤差信号振幅比および正規化変調係数と記録パワーとの関係を示す説明図
【図９】従来の技術による光学的情報記録再生装置を示すブロック図
【図１０】光ディスクの記録パワー学習領域を示す説明図
【図１１】従来の技術による記録パワー学習時の記録パワーを示す説明図
【図１２】再生波形のアシンメトリの説明図
【図１３】再生信号の変調度および正規化変調係数と記録パワーとの関係を示す説明図
【符号の説明】
１光ディスク
２ピック
３レーザ駆動回路
４レーザ出力制御回路
５光駆動手段
６初期記録情報読み込み回路
７変調度検出回路
８正規化変調係数演算回路
９下限記録パワー演算回路
１０光強度下限演算手段
１１記録パターン発生回路
１２記録パワー可変回路
１３最適記録パワー演算回路
１４ウォブル信号振幅検出回路
１５上限記録パワー演算回路
１６情報記録パワー決定回路
１７トラッキング誤差信号振幅検出回路
１８上限記録パワー演算回路
１９ウォブルトラック
２０光ビーム
２１データ領域
２２記録パワー学習領域[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical information recording / reproducing apparatus and a recording light intensity learning method for recording information on an optical recording medium.
[0002]
[Prior art]
Conventionally, as an optical recording medium, there are a CD Rewritable medium and a DVD Re-recordable medium. An optical information recording / reproducing apparatus and a recording light intensity learning method for recording information on these media are, for example, “DVD Specification for Re-recordable”. What is described in “Disc Part 1 PHYSICAL SPECIFICATIONS” is known.
[0003]
FIG. 9 shows the structure of a DVD Re-recordable which is an example of a conventional optical information recording / reproducing apparatus. The optical disc 1 is an optical recording medium (DVD-RW medium), and the optical disc 1 is irradiated with a light beam. A pick 2 on which a laser diode (hereinafter referred to as LD (Laser Diode)) is mounted, a laser driving circuit 3 for driving an LD in the pick 2, and a laser for instructing a desired laser output to the laser driving circuit 3 An output control circuit 4; an initial recording information reading circuit 6 for reading initial recording information recorded on the optical disc 1; a recording power variable circuit 12 for changing recording power based on the read initial recording information; and the optical disc 1 is a modulation degree detection circuit 7 for detecting the modulation degree of the reproduction signal from the recording pattern recorded on the recording pattern 7, A normalized modulation coefficient calculation circuit 8 that calculates a modulation degree normalized by the recording power from the detected modulation degree and recording power, and an optimum combination of the optical disc 1 and the pick 2 from the normalized modulation coefficient and initial recording information An optimum recording power calculation circuit 13 for obtaining a recording power and a recording pattern generation circuit 11 for generating an information recording pattern to be recorded on the optical disc 1 are constituted.
[0004]
On the optical disc 1, as shown in FIG. 10, a recording power learning area 22 for learning the recording power as necessary is provided in addition to the data area 21 for recording information when recording information on the inner periphery of the optical disc 1. .
[0005]
When the optical information recording / reproducing apparatus performs recording power learning, first, the recommended recording power Pi, which is the initial recording information recorded on the optical disc 1, is read by the initial recording information reading circuit 6. The recommended recording power Pi is an optimum recording power determined for each optical disc under a certain condition by a standard evaluator or the like. When information is actually recorded, since the optimum recording power differs due to a change in optical sensitivity of the recording medium due to a change in the LD wavelength due to a temperature state at the time of recording or a decrease in laser transmission efficiency due to dust on the pick 2, etc. It is necessary to learn the recording power corresponding to the recording state in the power learning area 22. Further, each optical information recording / reproducing apparatus has, as an optimum power control coefficient for each optical disc, a multiplication factor ρ (hereinafter referred to as optimum power multiplication factor ρ) for obtaining optimum recording power, a target normalized modulation coefficient γtarget (hereinafter referred to as γt). Hold).
[0006]
Next, the optical pick 2 is moved to the recording power learning area 22 provided in the inner peripheral portion of the optical disc 1, and for example, a random 8-16 encoded data pattern is generated as a recording power learning pattern from the recording pattern generation circuit 11. The recording power variable circuit 12 sets the recording power smaller than the value obtained by dividing the recommended recording power Pi by the optimum power multiplication factor ρ as the power learning start recording power Pw0, and increases the power learning recording power by a constant power as shown in FIG. A recording power learning pattern is recorded in the recording power learning area 22 with 10 levels of recording power (Pw0 to Pw9).
[0007]
At the time of detecting the modulation degree, a reproduction waveform corresponding to each recording power Pw is reproduced from the pick 2, and the modulation degree (m0 to m9) at each recording power is detected by the modulation degree detection circuit 7.
[0008]
FIG. 12 shows a reproduction waveform when a recording power learning pattern is recorded with a constant recording power. Since the recording power learning pattern is recorded with the same 8-16 encoded data pattern as that for recording information, 3T to 11T and 14T recording length marks (hereinafter referred to as marks) and unrecorded based on the recording unit time T It consists of a long space (hereinafter referred to as a space).
[0009]
The modulation degree detection circuit 7 calculates the modulation degree m using Equation 1 from the amplitude values AH1 and AL1 of the 14T space which is the longest space and the 14T mark which is the longest mark.
[0010]
[Expression 1]

[0011]
The modulation degree detection circuit 7 obtains the relationship between each recording power and the modulation degree m as shown in FIG. 13 from the recording power and the detected modulation degree m.
[0012]
The normalized modulation coefficient calculation circuit 8 calculates the relationship between each recording power and the normalized modulation coefficient γ as shown in FIG. 13 using Equation 2 from the relationship between the recording power and the modulation factor.
[0013]
[Expression 2]

[0014]
For example, the normalized modulation coefficient γ1 at the recording power Pw01 can be calculated from the modulation degrees m0 and m1 of the recording powers Pw0 and Pw1 using Equations 3 and 4.
[0015]
[Equation 3]

[0016]
[Expression 4]

[0017]
Next, the optimum recording power calculation circuit 13 obtains a target recording power Pt that is a recording power for realizing the target normalized modulation coefficient γt from the relationship between each recording power and the normalized modulation coefficient γ. Po is calculated as information recording power.
[0018]
[Equation 5]

[0019]
When recording information in the data area 21, the laser output control circuit 4 operates so as to obtain the information recording power determined by performing the recording power learning, and information is recorded with the optimum recording power in the power learning state. .
[0020]
[Problems to be solved by the invention]
In this optical information recording / reproducing apparatus, in order to obtain the optimum recording power based on the recommended recording power Pi recorded on the optical disc, the multiplication factor ρ for each optical disc obtained in advance, and the target normalized modulation coefficient γt, The optimum recording power under a certain condition by a standard evaluation machine can be obtained. However, in actual devices, there are factors that reduce the effective recording power, such as mechanical deviations such as tilt, and control errors such as defocus, and it is necessary to set the information recording power for actually recording information higher than the optimum recording power. There is.
[0021]
Also, optical recording media generally deteriorate the recording track groove when recording is repeated many times with a recording power higher than the optimum recording power, and the tracking error signal amplitude, which is the relative position information between the recording track groove and the light beam, decreases. In the worst case, however, tracking control becomes impossible.
[0022]
An object of the present invention is to realize recording power learning for determining recording power so that tracking control is not disabled even if the information recording power is set high.
[0023]
[Means for Solving the Problems]
In order to solve this problem, an optical information recording / reproducing apparatus according to the present invention includes an optical recording medium in which a recording track groove fluctuates in a radial direction at a constant period, and irradiates the optical recording medium with a light beam. Light irradiating means, light driving means for causing the light irradiating means to emit light at a desired light intensity, light intensity learning start light intensity (Pw0) and desired light intensity in a light intensity learning area in the optical recording medium Recording output control means for controlling to record the light intensity learning pattern at (Pwn), and initial recording for reading the track groove fluctuation signal limit amplitude ratio (δt) previously held in the optical information recording / reproducing apparatus as initial recording information and information reading means, a modulation degree detecting means for detecting a modulation degree from the amplitude of the reproduced signal of the optical intensity training pattern, periodic track grooves variation signal generated by the variation of the recording track groove Light intensity calculation and the track grooves varying signal amplitude detecting means, the lower light intensity to be recorded on said optical recording medium than the modulation of the recording area recorded in the plurality of light intensity in the light intensity calibration area for detecting the amplitude of the the lower limit calculating means, and the light intensity limit calculating means for calculating an upper limit light intensity for recording than the track grooves varying signal amplitude of the recorded recording area on the optical intensity calibration area on said optical recording medium, and the lower light intensity Information recording light intensity determining means for determining the light intensity for recording information on the optical recording medium from the upper limit light intensity, and the recording in which the light intensity upper limit calculating means records at the desired light intensity (Pwn). The track groove fluctuation signal amplitude (wn) of the area is divided (wn / w0) by the track groove fluctuation signal amplitude (w0) of the recording area recorded by the light intensity learning start light intensity (Pw0) to obtain the light intensity (P means for calculating the track groove fluctuation signal amplitude ratio (δn) at wn), means for comparing the magnitude of the track groove fluctuation signal amplitude ratio (δn) and the track groove fluctuation signal limit amplitude ratio (δt); When the track groove fluctuation signal amplitude ratio (δn) becomes equal to or less than the track groove fluctuation signal limit amplitude ratio (δt), the light intensity (Pwn) is determined to be an upper limit light intensity .
[0024]
Further, another optical information recording / reproducing apparatus of the present invention includes a light irradiating means for irradiating an optical recording medium having a recording track groove with a light beam, and an optical drive for causing the light irradiating means to emit light at a desired light intensity. and means, recorded output control means for controlling so as to record the light intensity training patterns in the light intensity learning start light intensity (Pw0) and the desired light intensity (Pwn) in the light intensity calibration area in the optical recording medium, the initial Initial recording information reading means for reading the tracking error signal limit amplitude ratio (τt) previously held in the optical information recording / reproducing apparatus as recording information, and modulation for detecting the modulation degree from the amplitude of the reproduction signal of the light intensity learning pattern track the amplitude detecting means, by moving the light beam across the recording track groove turn off the tracking control for detecting a tracking error signal A ring error signal detection means, and the light intensity lower limit calculating means for calculating a lower limit light intensity for recording than the modulation of the recorded recording area in the plurality of light intensity in the light intensity calibration area on said optical recording medium, the light and the light intensity limit calculating means for calculating an upper limit light intensity from the tracking error signal amplitude of the recorded recording area intensity learning area is recorded in the optical recording medium, said optical recording than the upper light intensity and the lower light intensity Information recording light intensity determining means for determining the light intensity for recording information on the medium, wherein the light intensity upper limit calculating means records the tracking error signal amplitude (TEn) of the recording area recorded at the desired light intensity (Pwn). ) Is divided (TEn / TE0) by the tracking error signal amplitude (TE0) of the recording area recorded by the light intensity learning start light intensity (Pw0) to obtain the light intensity (Pwn). Means for calculating the tracking error signal amplitude ratio (τn), means for comparing the tracking error signal amplitude ratio (τn) and the tracking error signal limit amplitude ratio (τt), and the tracking error signal amplitude ratio When (τn) becomes equal to or less than the tracking error signal limit amplitude ratio (τt), the light intensity (Pwn) is used as the upper limit light intensity .
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS.
[0026]
(Embodiment 1)
FIG. 1 shows an embodiment of an optical information recording / reproducing apparatus according to the present invention. In FIG. 1, reference numeral 1 denotes an optical disk as an optical recording medium, in which a recording track groove for recording information is formed. In the groove, a wobble track 19 is formed which fluctuates in a constant cycle in the radial direction in order to generate a recording clock as shown in FIG.
[0027]
Reference numeral 2 denotes a pick on which an LD for irradiating the optical disk 1 with a light beam is mounted as a light irradiation means. Reference numeral 5 denotes a laser drive circuit 3 and a laser output control circuit 4 for driving the LD with a light drive means.
[0028]
6 is an initial recording information reading circuit for reading the initial recording information recorded on the optical disc 1, 7 is a modulation degree detection circuit for detecting the modulation degree from the amplitude of the reproduction signal by a modulation degree detection means, and 10 is a light intensity lower limit calculation. Information is recorded on the basis of the normalized modulation coefficient and the normalized modulation coefficient calculation circuit 8 for calculating the modulation degree normalized by the recording power from the modulation degree detected from the modulation degree detection circuit 7 and the recording power. A lower limit recording power calculation circuit 9 for calculating a lower limit light intensity, and 12 is a recording power control circuit for controlling a recording power used for recording power learning from a recommended recording power of initial recording information and an increment of recording power by a recording output control means; Reference numeral 14 denotes track groove fluctuation signal amplitude detection means for detecting the amplitude of a track groove fluctuation signal (hereinafter referred to as a wobble signal) generated by a wobble track. Bull signal amplitude detection circuit, 15 is an upper limit recording power calculation circuit which is a light intensity upper limit calculation means for calculating the upper limit light intensity to be recorded on the optical recording medium based on the amount of decrease in wobble signal amplitude due to recording power, 16 It is an information recording power determination circuit which is information recording light intensity determination means for determining the light intensity for recording information based on the lower limit recording power and the upper limit recording power.
[0029]
FIG. 2 shows an embodiment of the recording light intensity learning method of the present invention.
[0030]
The optical information recording / reproducing apparatus of the present invention configured as described above and the recording light intensity learning (hereinafter referred to as recording power learning) method of the present invention will be described with reference to FIGS.
[0031]
When the optical information recording / reproducing apparatus performs recording power learning, first, the recommended recording power Pi, which is the initial recording information recorded on the optical disc 1, is read by the initial recording information reading circuit 6. Further, a gain ρm (hereinafter referred to as a lower limit recording power gain ρm) and a lower limit normalized modulation coefficient γm for obtaining a lower limit recording power which is recording information for each optical disc held by each optical information recording / reproducing apparatus, an upper limit The wobble signal limit amplitude ratio δt for obtaining the recording power and the recording power increment Pd, which is the amount for increasing the recording power during recording power learning, are taken in.
[0032]
The optimum recording power multiplication factor ρ and target normalized modulation coefficient γt described in the prior art are values under a certain condition in a standard evaluator or the like, but the optical recording / reproducing apparatus and light intensity learning method of the present invention The lower limit recording power multiplication factor ρm and the lower limit normalized modulation coefficient γm may be equal to the optimum recording power multiplication factor ρ and the target normalized modulation coefficient γt.
[0033]
Next, the optical pick 2 is moved to the recording power learning area 22 provided in the inner peripheral portion of the optical disc 1, and for example, a random 8-16 encoded data pattern is generated as a recording power learning pattern from the recording pattern generation circuit 11. The recording power variable circuit 12 records a recording power learning pattern in the recording power learning area 22 with a recording power smaller than a value obtained by dividing the lower limit recording power Pi by the lower limit power multiplication factor ρm as a power learning start recording power Pw0. .
[0034]
When reproducing the recording power learning pattern, the modulation degree detection circuit 7 detects the modulation degree m0 at the recording power Pw0, and the wobble signal amplitude detection circuit 14 detects the wobble signal amplitude w0.
[0035]
When the light beam 20 passes along the wobble track 19 as shown in FIG. 3, a wobble signal as shown in FIG. 4 is detected. In the case of a DVD-RW medium, the frequency of this wobble signal can be detected at a standard speed of about 140 KHz.
[0036]
The upper limit recording power calculation circuit 15 calculates the wobble signal amplitude ratio δ from the wobble signal amplitude w at the recording power Pw using Equation 6.
[0037]
[Formula 6]

[0038]
Therefore, the wobble signal amplitude ratio δ0 at the power learning start recording power Pw0 is 1. Further, the upper limit recording power calculation circuit 15 compares the wobble signal amplitude ratio δ with the wobble signal limit amplitude ratio δt, and if the wobble signal amplitude ratio δ is larger than the wobble signal limit amplitude ratio δt, the recording power variable circuit 12 Command the power Pw to increase by the recording power increment Pd.
[0039]
The recording power learning circuit 12 records the recording power learning pattern again in the recording power learning area by the recording power Pw1 that is increased by the recording power increment Pd from the power learning start recording power Pw0 by the recording power variable circuit 12, and the modulation degree m1 and the wobble signal w1. Is detected.
[0040]
The normalized modulation coefficient calculation circuit 8 calculates the normalized modulation coefficient γ1 corresponding to the recording power Pw01 using Equation 3.
[0041]
The upper limit recording power calculation circuit 15 calculates the wobble signal amplitude ratio δ1 based on the wobble signal amplitudes w1 to w0 at the recording power Pw1 using Equation 6. Further, the upper limit recording power calculation circuit 15 compares the wobble signal amplitude ratio δ1 with the wobble signal limit amplitude ratio δt. Command the power Pw1 to increase by the recording power increment Pd.
[0042]
Thus, every time the recording power is increased, a recording power learning pattern is recorded in the recording power learning area, the modulation degree m and the wobble signal amplitude w are detected, and the normalized modulation coefficient γ and the wobble signal amplitude ratio δ are calculated. It is obtained and compared with the wobble signal limit amplitude ratio δt.
[0043]
When the wobble signal amplitude ratio δn when recording with the recording power Pwn becomes equal to or less than the wobble signal limit amplitude ratio δt, the upper limit recording power Pwmax is set to Pwn, and the recording into the recording power learning area is ended.
[0044]
The lower limit recording power calculation circuit 9 obtains a recording power Pm corresponding to the lower limit normalized modulation coefficient γm from the recording power and the normalized modulation coefficient γ, and a value obtained by multiplying Pm by the lower limit recording power multiplication factor ρm as the lower limit recording power Pwmin. To do. The information recording power determination circuit 16 sets the recording power between the lower limit recording power Pwmin and the upper limit recording power Pwmax as the information recording power P0 for recording information.
[0045]
For the information recording power P0, for example, a recording power decrease due to a tilt residual or a servo control error is measured in advance on the lower limit recording power Pwmin, and the recording power obtained by adding the recording power is compared with the upper limit recording power Pwmax. There is a method of determining a recording power having a small value as the information recording power P0.
[0046]
When information is actually recorded in the data area, the information recording power determination circuit 16 instructs the laser output control circuit 4 to obtain the information recording power P0 determined by the recording power learning, and records information with an appropriate recording power. It becomes possible to do.
[0047]
In the above description, the modulation degree is detected and the normalized modulation coefficient is calculated after recording at a predetermined recording power. However, if the learning pattern is recorded in a different area for each recording power, the modulation degree is calculated. It goes without saying that the same result can be obtained even if the detection and calculation of the normalized modulation coefficient are performed collectively after determining the upper limit recording power.
[0048]
(Embodiment 2)
FIG. 6 shows one embodiment of the optical information recording / reproducing apparatus of the present invention. In FIG. 6, the difference from the first embodiment is detected by the tracking error signal amplitude detection circuit 17 and the tracking error signal amplitude detection circuit 17. The upper limit recording power calculation circuit 18 obtains the upper limit recording power from the tracking error signal amplitude.
[0049]
FIG. 7 shows an embodiment of the recording light intensity learning method of the present invention.
[0050]
The optical information recording / reproducing apparatus of the present invention configured as described above and the recording light intensity learning method of the present invention will be described with reference to FIGS.
[0051]
When the optical information recording / reproducing apparatus performs recording power learning, first, the recommended recording power Pi, which is the initial recording information recorded on the optical disc 1, is read by the initial recording information reading circuit 6. Also, the lower limit recording power multiplication factor ρm, the lower limit normalized modulation coefficient γm, the tracking error signal limit amplitude ratio τt, and the recording power increment Pd, which are recording information for each optical disc held by each optical information recording / reproducing apparatus, are taken in.
[0052]
Next, the optical pick 2 is moved to the recording power learning area 22 provided in the inner peripheral portion of the optical disc 1, and for example, a random 8-16 encoded data pattern is generated as a recording power learning pattern from the recording pattern generation circuit 11. The recording power variable circuit 12 records a recording power learning pattern in the recording power learning area with a recording power smaller than a value obtained by dividing the lower limit recording power Pi by the lower limit power multiplication factor ρm as a power learning start recording power Pw0.
[0053]
When reproducing the recording power learning pattern, the modulation degree detection circuit 7 detects the modulation degree m0 at the recording power Pw0.
[0054]
Next, the tracking control is turned off, the light beam is moved across the recording track groove recorded at the recording power Pw0, and the tracking error signal amplitude TE0 is detected by the tracking error signal amplitude detection circuit 17 at that time.
[0055]
The upper limit recording power calculation circuit 18 uses Equation 7 to calculate the tracking error signal amplitude ratio τ from the tracking error signal amplitude TE at the recording power Pw.
[0056]
[Expression 7]

[0057]
Therefore, the tracking error signal amplitude ratio τ 0 at the power learning start recording power Pw 0 is 1. The upper limit recording power calculation circuit 18 compares the tracking error signal amplitude ratio τ with the tracking error signal limit amplitude ratio τt. If the tracking error signal amplitude ratio τ is larger than the tracking error signal limit amplitude ratio τt, the recording power variable circuit 12 is instructed to increase the recording power Pw by the recording power increment Pd.
[0058]
The recording power learning pattern is recorded again in the recording power learning area by the recording power Pw1 that is increased by the recording power increment Pd from the power learning start recording power Pw0 by the recording power variable circuit 12, and the modulation degree m1 and the wobble signal TE1 are recorded. Is detected.
[0059]
The normalized modulation coefficient calculation circuit 8 calculates the normalized modulation coefficient γ1 corresponding to the recording power Pw01 using Equation 3.
[0060]
The upper limit recording power calculation circuit 18 calculates the tracking error signal amplitude ratio τ1 using the equation 7 with reference to the tracking error signal amplitude TE1 to TE0 at the recording power Pw1. The upper limit recording power calculation circuit 18 compares the tracking error signal amplitude ratio τ1 with the tracking error signal limit amplitude ratio τt. If the tracking error signal amplitude ratio τ1 is larger than the tracking error signal limit amplitude ratio τt, the recording power variable circuit 12 is instructed to increase the recording power Pw1 by the recording power increment Pd.
[0061]
In this way, each time the recording power is increased, a recording power learning pattern is recorded in the recording power learning area, the modulation degree m and the tracking error signal amplitude TE are detected, the normalized modulation coefficient γ, the tracking error signal amplitude ratio. τ is obtained and compared with the tracking error signal limit amplitude ratio τt.
[0062]
When the tracking error signal amplitude ratio τn when recording with the recording power Pwn becomes equal to or less than the tracking error signal limit amplitude ratio τt, the upper limit recording power Pwmax is set to Pwn, and the recording in the recording power learning area is ended.
[0063]
The lower limit recording power calculation circuit 9 obtains a recording power Pm corresponding to the lower limit normalized modulation coefficient γm from the recording power and the normalized modulation coefficient γ, and a value obtained by multiplying Pm by the lower limit recording power multiplication factor ρm as the lower limit recording power Pwmin. To do.
[0064]
The information recording power determination circuit 16 sets the recording power between the lower limit recording power Pwmin and the upper limit recording power Pwmax as the information recording power P0 for recording information.
[0065]
For the information recording power P0, for example, a recording power decrease due to a tilt residual or a servo control error is measured in advance on the lower limit recording power Pwmin, and the recording power obtained by adding the recording power is compared with the upper limit recording power Pwmax. There is a method of determining a recording power having a small value as the information recording power P0.
[0066]
When information is actually recorded in the data area, the information recording power determination circuit 16 instructs the laser output control circuit 4 to obtain the information recording power P0 determined by the recording power learning, and records information with an appropriate recording power. It becomes possible to do.
[0067]
In the above description, the modulation degree is detected and the normalized modulation coefficient is calculated after recording at a predetermined recording power. However, if the learning pattern is recorded in a different area for each recording power, the modulation degree is calculated. It goes without saying that the same result can be obtained even if the detection and calculation of the normalized modulation coefficient are performed collectively after determining the upper limit recording power.
[0068]
【The invention's effect】
As described above, according to the present invention, since the lower limit recording power and the upper limit recording power are obtained in the recording light intensity learning for determining the information recording power for recording information, and the recording power is determined between them, the recording power is too high. There is no deterioration of the recording track groove due to repeated overwriting, and there is always an effect that the recording power at the time of information recording can be optimized.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an optical information recording / reproducing apparatus according to Embodiment 1 of the present invention. FIG. 2 is an explanatory diagram of a recording light intensity learning method according to Embodiment 1 of the present invention. FIG. 4 is an explanatory diagram showing periodic fluctuations of track grooves. FIG. 4 is an explanatory diagram showing wobble signals detected by periodic fluctuations of recording track grooves on an optical disc. FIG. 5 is a wobble signal amplitude ratio according to Embodiment 1 of the invention. FIG. 6 is a block diagram showing an optical information recording / reproducing apparatus according to a second embodiment of the present invention. FIG. 7 is a recording diagram according to a second embodiment of the present invention. FIG. 8 is a diagram illustrating a light intensity learning method. FIG. 8 is a diagram illustrating a relationship between a tracking error signal amplitude ratio, normalized modulation coefficient, and recording power according to Embodiment 2 of the present invention. Record FIG. 10 is an explanatory diagram showing a recording power learning area of an optical disc. FIG. 11 is an explanatory diagram showing recording power at the time of recording power learning by a conventional technique. FIG. 12 is an explanatory diagram of reproduction waveform asymmetry. FIG. 13 is an explanatory diagram illustrating the relationship between the modulation degree of a reproduction signal, the normalized modulation coefficient, and the recording power.
DESCRIPTION OF SYMBOLS 1 Optical disk 2 Pick 3 Laser drive circuit 4 Laser output control circuit 5 Optical drive means 6 Initial recording information reading circuit 7 Modulation degree detection circuit 8 Normalization modulation coefficient calculation circuit 9 Lower limit recording power calculation circuit 10 Light intensity lower limit calculation means 11 Recording pattern Generation circuit 12 Recording power variable circuit 13 Optimal recording power calculation circuit 14 Wobble signal amplitude detection circuit 15 Upper limit recording power calculation circuit 16 Information recording power determination circuit 17 Tracking error signal amplitude detection circuit 18 Upper limit recording power calculation circuit 19 Wobble track 20 Light beam 21 Data area 22 Recording power learning area

Claims

An optical recording medium in which the recording track groove varies in the radial direction at a constant period, a light irradiation means for irradiating the optical recording medium with a light beam, and causing the light irradiation means to emit light at a desired light intensity A light output means, a recording output control means for controlling to record a light intensity learning pattern at a light intensity learning start light intensity (Pw0) and a desired light intensity (Pwn) in a light intensity learning area in the optical recording medium; , Initial recording information reading means for reading the track groove fluctuation signal limit amplitude ratio (δt) previously held in the optical information recording / reproducing apparatus as initial recording information, and the modulation degree from the amplitude of the reproduction signal of the light intensity learning pattern Modulation degree detecting means for detecting, track groove fluctuation signal amplitude detecting means for detecting an amplitude of a track groove fluctuation signal generated by periodic fluctuation of the recording track groove, and the light intensity A light intensity lower limit calculating means for calculating a lower limit light intensity to be recorded on said optical recording medium than the modulation of the recording area recorded in the plurality of light intensity in the learning region, the recorded recording area on the light intensity calibration area and the light intensity limit calculating means for calculating an upper limit light intensity for recording than the track grooves varying signal amplitude to the optical recording medium, the light intensity for recording information on said optical recording medium from the upper light intensity and the lower light intensity An information recording light intensity determination means for determining ,
The track groove of the recording area where the light intensity upper limit calculation means records the track groove fluctuation signal amplitude (wn) of the recording area recorded with the desired light intensity (Pwn) with the light intensity learning start light intensity (Pw0). Means for calculating the track groove fluctuation signal amplitude ratio (δn) at the light intensity (Pwn) by dividing (wn / w0) by the fluctuation signal amplitude (w0), the track groove fluctuation signal amplitude ratio (δn) and the Means for comparing the magnitude with the track groove fluctuation signal limit amplitude ratio (δt), and the light intensity when the track groove fluctuation signal amplitude ratio (δn) is less than or equal to the track groove fluctuation signal limit amplitude ratio (δt). An optical information recording / reproducing apparatus comprising: (Pwn) as the upper limit light intensity .

The recording power control means controls so as gradually to increase the light intensity from the light intensity learning initial strength which is previously set for each optical recording medium having different characteristics, the light intensity by the light intensity upper limit calculating means and the 2. The optical information recording / reproducing apparatus according to claim 1, wherein when the upper limit light intensity is reached, the light intensity is controlled not to increase beyond that.

The information recording light intensity determining means, and the light intensity adding means for obtaining the sum light intensity plus a constant value to the lower limit light intensity, the light intensity towards the said summing light intensity small by comparing the upper light intensity the optical information recording reproducing apparatus according to claim 1 wherein comprising a light intensity selecting means and the light intensity for recording the information.

Light irradiation means for irradiating an optical recording medium having a recording track groove with a light beam, light driving means for causing the light irradiation means to emit light at a desired light intensity, and a light intensity learning area in the optical recording medium. Recording output control means for controlling to record a light intensity learning pattern at a light intensity learning start light intensity ( Pw0 ) and a desired light intensity (Pwn), and pre-stored in the optical information recording / reproducing apparatus as initial recording information Initial recording information reading means for reading the tracking error signal limit amplitude ratio (τt), modulation amplitude detecting means for detecting the modulation degree from the amplitude of the reproduction signal of the light intensity learning pattern, and the recording track with tracking control turned off and a tracking error signal detecting means for detecting a tracking error signal by moving the light beam across the groove, the light intensity calibration area A plurality of light intensity lower limit calculating means for calculating a lower limit light intensity to be recorded on said optical recording medium than the modulation of the recorded recording area in the light intensity, the tracking error signal of the recorded recording area on the light intensity calibration area information recording for determining the light intensity limit calculating means for calculating an upper limit light intensity to be recorded on said optical recording medium than the amplitude, the light intensity for recording information on said optical recording medium from the upper light intensity and the lower light intensity Light intensity determining means,
The tracking error of the recording area in which the light intensity upper limit calculating means records the tracking error signal amplitude (TEn) of the recording area recorded with the desired light intensity (Pwn) with the light intensity learning start light intensity (Pw0). Means for calculating the tracking error signal amplitude ratio (τn) at the light intensity (Pwn) by dividing (TEn / TE0) by the signal amplitude (TE0), the tracking error signal amplitude ratio (τn) and the tracking error signal The means for comparing the magnitude with the limit amplitude ratio (τt), and when the tracking error signal amplitude ratio (τn) is less than or equal to the tracking error signal limit amplitude ratio (τt), the light intensity (Pwn) is set to the upper limit. An optical information recording / reproducing apparatus comprising means for obtaining light intensity .

The recording power control means controls so as gradually to increase the light intensity from the light intensity learning initial strength which is previously set for each optical recording medium having different characteristics, the light intensity by the light intensity upper limit calculating means and the 5. The optical information recording / reproducing apparatus according to claim 4, wherein when the upper limit light intensity is reached, the light intensity is controlled not to increase beyond that.

The information recording light intensity determining means, and the light intensity adding means for obtaining the sum light intensity plus a constant value to the lower limit light intensity, the light intensity towards the said summing light intensity small by comparing the upper light intensity the optical information recording reproducing apparatus according to claim 4, wherein comprising a light intensity selecting means and the light intensity for recording the information.