JP3277824B2 - Optical head and optical disk recording device - Google Patents
Optical head and optical disk recording deviceInfo
- Publication number
- JP3277824B2 JP3277824B2 JP27757196A JP27757196A JP3277824B2 JP 3277824 B2 JP3277824 B2 JP 3277824B2 JP 27757196 A JP27757196 A JP 27757196A JP 27757196 A JP27757196 A JP 27757196A JP 3277824 B2 JP3277824 B2 JP 3277824B2
- Authority
- JP
- Japan
- Prior art keywords
- order diffracted
- diffracted light
- light
- recording
- beam spot
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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- Optical Recording Or Reproduction (AREA)
- Optical Head (AREA)
Description
【０００１】[0001]
【発明の属する技術分野】この発明は新規な構成の光ヘ
ッドおよびこの光ヘッドを用いた光ディスク記録装置に
関し、差動トラッキング方式を用いた高精度のトラッキ
ングを行いつつ、記録時にリアルタイムでの最適レーザ
パワー調整、ベリファイ、ディスク上の傷の予知等を可
能にしたものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical head having a novel configuration and an optical disk recording apparatus using the optical head, and performs an optimum laser in real time during recording while performing high-accuracy tracking using a differential tracking system. It enables power adjustment, verification, prediction of scratches on the disc, and the like.
【０００２】[0002]
（１） トラッキング制御 従来の光ディスク記録装置のトラッキング制御方式は、
３ビーム法やプッシュプル法が一般的であった。３ビー
ム法は、メインビームの前後に２本のサブビームをトラ
ック中心から左右方向にややずらして照射し、この２本
のサブビームのディスク反射光量の差を検出してトラッ
キングエラーを検出するものである。プッシュプル法
は、ディスク上のピットや案内溝で反射回折された光を
トラック中心に対して対称配置された２分割光検出器で
受光して、その２つの受光部での受光量の差によりトラ
ッキングエラーを検出するものである。(1) Tracking control The tracking control method of the conventional optical disk recording device is as follows.
The three-beam method and the push-pull method were common. In the three-beam method, two sub beams are irradiated before and after the main beam with a slight shift from the center of the track in the left-right direction, and a difference in the amount of reflected light of the two sub beams on the disk is detected to detect a tracking error. . In the push-pull method, light reflected and diffracted by pits and guide grooves on a disc is received by a two-segment photodetector symmetrically arranged with respect to the center of the track, and the difference in the amount of light received by the two light receiving units is obtained. This is to detect a tracking error.
【０００３】３ビーム法は、再生用としては最も安定な
方法であるが、これを記録用に使用すると、先行するサ
ブビームのスポットは未記録部を通過するのに対し、後
行するサブビームのスポットは既記録部を通過するた
め、反射光量が異なって、トラッキングエラー信号にオ
フセットが生じる欠点があった。[0003] The three-beam method is the most stable method for reproduction. However, when this method is used for recording, the spot of the preceding sub-beam passes through the unrecorded portion, whereas the spot of the subsequent sub-beam passes. However, since the light passes through a recorded portion, the amount of reflected light is different, and there is a disadvantage that an offset occurs in the tracking error signal.
【０００４】一方、プッシュプル法では、対物レンズが
シフトしたり、ディスク径方向にそり、傾き等が生じて
いると、トラッキングエラー信号にオフセットが生じ、
トラッキング追従量が十分に確保できなくなる欠点があ
った。On the other hand, in the push-pull method, if the objective lens is shifted, or if the objective lens is warped or tilted in the radial direction, an offset occurs in the tracking error signal,
There is a disadvantage that the tracking amount cannot be sufficiently secured.
【０００５】これら従来の３ビーム法やプッシュプル法
の欠点を解消したトラッキング制御方式として、いわゆ
る差動プッシュプル法と呼ばれているものがある。これ
は、３つのビームスポットをトラック前後方向の位置で
トラック左右方向に１／２トラックピッチずつずらして
配置し、各スポットの反射光を２分割光検出器でそれぞ
れ検出し、各２分割検出器ごとに２信号を引算して３つ
のプッシュプル信号を得て、これらをオフセットを打ち
消すように所定の演算式で演算してトラッキングエラー
を検出するようにしたものである。There is a so-called differential push-pull method as a tracking control method which has solved the disadvantages of the conventional three-beam method and push-pull method. In this method, three beam spots are arranged at positions in the front-rear direction of the track and shifted by 1/2 track pitch in the left-right direction of the track, and the reflected light of each spot is detected by a two-segment photodetector. Each time, two signals are subtracted to obtain three push-pull signals, which are calculated by a predetermined arithmetic expression so as to cancel the offset, and a tracking error is detected.
【０００６】（２） 最適書込パワーの設定 光ディスク記録時のレーザ光の最適書込パワーは光ディ
スクの種類によって異なるため、入力信号の実際の記録
（実記録）を行うのに先立って予め試し書きを行って最
適書込パワーが設定される。例えば、ＣＤ−Ｗｒｉｔｅ
Ｏｎｃｅ（ＣＤ−ＷＯ）規格では、この試し書きを行
うエリアがＰＣＡ（Power CaliblationArea）としてデ
ィスクの最内周に設けられておりＯＰＣ（Optimum Powe
r Control ）と呼ばれる一連の動作によって最適書込パ
ワーが設定される。(2) Setting of the optimum writing power The optimum writing power of the laser beam at the time of recording on the optical disk differs depending on the type of the optical disk. Therefore, test writing is performed in advance before actual recording (actual recording) of the input signal. To set the optimum write power. For example, CD-Write
In the Once (CD-WO) standard, an area for performing the test writing is provided on the innermost periphery of the disc as a PCA (Power Calibration Area), and the OPC (Optimum Powe
The optimum write power is set by a series of operations called rControl).
【０００７】従来の光ディスク記録装置におけるＯＰＣ
動作は、書込パワーをあるステップずつ変化させてテス
ト記録を行い、このテスト記録したエリアを再生してア
シンメトリ値（ＨＦ信号の非対称性を示す指標）を算出
し、最適アシンメトリ値とされる値（例えば０．０４）
が得られる書込パワー値を最適書込パワー値として定め
て、これを実記録時の書込パワー値として設定してい
た。OPC in a conventional optical disk recording apparatus
In the operation, test recording is performed by changing the write power by a certain step at a time, the area in which the test recording is performed is reproduced, an asymmetry value (an index indicating the asymmetry of the HF signal) is calculated, and a value to be an optimum asymmetry value is calculated. (For example, 0.04)
Is determined as the optimum write power value, and this is set as the write power value during actual recording.
【０００８】（３） 最適書込パワーを保持して書込を
行うための書込パワー制御 実記録に先立ち、最適書込パワーで記録した光ディスク
の記録部分の反射光レベルを検出し、サンプルホールド
回路でその反射光レベルをサンプルホールドし、ＡＤ変
換回路でそのレベルをＡＤ変換し、演算回路でその値を
加工し、ＣＰＵにその値をＡＬＰＣ（Automatic Laser
Power Control ）の目標値として記憶する。(3) Write power control for performing writing while holding the optimum write power Prior to actual recording, the reflected light level of the recording portion of the optical disk recorded with the optimum write power is detected, and sample hold is performed. The circuit samples and holds the reflected light level, the AD converter converts the level to AD, the arithmetic circuit processes the value, and sends the value to the CPU using the ALPC (Automatic Laser
Power Control) is stored as the target value.
【０００９】そして、実記録時には、随時記録部分の反
射光レベルを検出し、前記サンプルホールド回路でその
反射光レベルをサンプルホールドし、ＡＤ変換回路でそ
のレベルをＡＤ変換し、前記演算回路でその値を加工
し、ＡＬＰＣ回路で前記ＣＰＵに記録されている目標値
とその値が一致するように、記録レーザパワーを制御す
る。At the time of actual recording, the reflected light level of the recorded portion is detected at any time, the reflected light level is sampled and held by the sample and hold circuit, the level is AD converted by the AD conversion circuit, and the arithmetic and control circuit performs the AD conversion. The value is processed, and the recording laser power is controlled by the ALPC circuit so that the target value matches the target value recorded in the CPU.
【００１０】（３） ベリファイ 実記録終了後に記録した部分を再生し、もとの記録デー
タと対比してベリファイを行う。(3) Verify The recorded portion is reproduced after the end of the actual recording, and the verify is performed by comparing with the original recorded data.
【００１１】[0011]
【発明が解決しようとする課題】従来の光ディスク記録
装置は、ＯＰＣ動作が実記録に先立って行われるため、
実記録を開始するまでに時間がかかる問題があった。ま
た実記録を行いながらのＡＬＰＣ動作は、複雑な回路構
成が必要で部品点数が多く、コストアップやサイズアッ
プにつながる問題があった。また、一旦ＯＰＣ動作によ
って最適記録レーザパワーを求めて実記録を行っても、
ディスク径方向位置による記録時の特性のばらつき等に
よる最適レーザパワー値の変動には対応することができ
なかった。また、ベリファイは実記録終了後に記録部分
を再生して行うため、実記録開始からベリファイ終了ま
で長い時間を要していた。また、ディスクに傷がついて
いると、実記録時にエラーを起こし、書込み不能になる
ことがあった。In the conventional optical disk recording apparatus, since the OPC operation is performed prior to the actual recording,
There was a problem that it took time to start actual recording. In addition, the ALPC operation while performing actual recording requires a complicated circuit configuration, has a large number of parts, and has a problem of increasing cost and size. Further, even if the actual recording is once performed by obtaining the optimum recording laser power by the OPC operation,
It was not possible to cope with a variation in the optimum laser power value due to a variation in characteristics at the time of recording depending on the position in the disk radial direction. In addition, since the verification is performed by reproducing the recorded portion after the end of the actual recording, it takes a long time from the start of the actual recording to the end of the verification. Further, if the disc is damaged, an error may occur at the time of actual recording and writing may not be possible.
【００１２】この発明は、前記従来の技術における問題
点を解決して、差動トラッキング方式を用いた高精度の
トラッキングを行いつつ、記録時にリアルタイムでの最
適レーザパワー調整、ベリファイ、ディスク上の傷の予
知等を可能にした光ヘッドおよびこの光ヘッドを用いた
光ディスク記録装置を提供しようとするものである。The present invention solves the above-mentioned problems in the prior art, and performs real-time optimal laser power adjustment, verification, and scratches on a disk during recording while performing high-precision tracking using a differential tracking method. It is an object of the present invention to provide an optical head capable of predicting the optical disc and an optical disk recording apparatus using the optical head.
【００１３】[0013]
【課題を解決するための手段】この発明の光ヘッドは、
１本のレーザ光を０次回折光、±１次回折光および±２
次回折光の少なくとも５本の光に分割し、０次回折光の
ビームスポットが光ディスクの１本のトラック上に位置
しているときに、＋２次回折光のビームスポットがそれ
に隣接する１本外側のトラック上に位置し、＋１次回折
光のビームスポットが０次回折光のビームスポットと＋
２次回折光のビームスポットの中間に位置し、−２次回
折光のビームスポットが０次回折光のビームスポットが
位置しているトラックに隣接する１本内側のトラック上
に位置し、−１次回折光のビームスポットが０次回折光
のビームスポットと−２次回折光のビームスポットの中
間に位置するように、それぞれ配置し、各回折光のディ
スクからの反射光を個別に検出する（ただし、±２次回
折光については、使用形態によっては、＋２次回折光あ
るいは−２次回折光の一方の反射光のみを受光するだけ
で足りる場合もある。）ようにしたものである。An optical head according to the present invention comprises:
One laser beam is divided into 0 order diffracted light, ± 1 order diffracted light and ± 2 order diffracted light.
When the beam spot of the 0th-order diffracted light is located on one track of the optical disc, the beam spot of the + 2nd-order diffracted light is split on at least one outer track adjacent thereto. And the beam spot of the + 1st-order diffracted light is the same as the beam spot of the 0th-order diffracted light.
The beam spot of the −2nd-order diffracted light is located on the inner track adjacent to the track where the beam spot of the 0th-order diffracted light is located in the middle of the beam spot of the 2nd-order diffracted light. The beam spots are arranged so as to be located between the beam spot of the 0th-order diffracted light and the beam spot of the -2nd-order diffracted light, and the reflected light of each diffracted light from the disk is individually detected (however, ± 2nd-order diffracted light In some cases, it may be sufficient to receive only one of the + 2nd-order diffracted light and the -2nd-order diffracted light depending on the use form.)
【００１４】また、この発明の光ディスク記録装置は、
上記光ヘッドを用いて、レーザ光を記録信号で変調して
光ディスクに照射し、ディスクの内周側のトラックから
外周側のトラックに順次記録を行う光ディスク記録装置
であって、０次回折光を用いて記録を行い、０次光およ
び±１次回折光の受光信号を用いて差動プッシュプル法
によりトラッキング制御を行うようにしている。また、
−２次回折光（記録用０次回折光に後行する光）の受光
信号に含まれる再生信号成分のアシンメトリ値を検出し
て、０次回折光で記録を行いながら最適パワー調整を行
ったり、−２次回折光の受光信号に含まれる再生信号成
分ともとの記録信号とを比較することにより、０次回折
光で記録を行いながらベリファイを行うようにしてい
る。また、＋２次回折光（記録用０次回折光に先行する
光）を用いて記録前のトラックの傷等の欠陥を検出し
て、欠陥が検出された場合には、トラッキングサーボ系
のループゲインを低下させることにより、傷によるトラ
ック外れを防止するようにしている。Further, the optical disk recording apparatus of the present invention comprises:
An optical disk recording device that modulates a laser beam with a recording signal using the optical head and irradiates the optical disk with an optical signal to sequentially record data from an inner track to an outer track of the disk, using 0-order diffracted light. Recording is performed, and tracking control is performed by the differential push-pull method using the received light signals of the 0th-order light and ± 1st-order diffracted light. Also,
The asymmetry value of the reproduction signal component included in the received light signal of the −2nd-order diffracted light (light following the recording 0th-order diffracted light) is detected, and the optimum power adjustment is performed while recording with the 0th-order diffracted light, or −2. By comparing the reproduced signal component included in the received light signal of the next-order diffracted light with the original recording signal, verification is performed while recording is performed with the zero-order diffracted light. Further, a defect such as a scratch on a track before recording is detected using + 2nd-order diffracted light (light preceding the 0th-order diffracted light for recording), and if a defect is detected, the loop gain of the tracking servo system is reduced. By doing so, the track is prevented from coming off due to the scratch.
【００１５】なお、記録時の−２次回折光の受光信号に
は、再生信号成分のほか記録信号成分が含まれているの
で、最適パワー調整やベリファイにおいては、−２次回
折光の受光信号から記録信号成分を除去して再生信号成
分のみを抽出する。−２次回折光の受光信号から記録信
号成分を除去する方法としては、例えば未記録トラック
上をトレースしている＋２次回折光の受光信号が記録信
号成分のみからなるので、−２次回折光の受光信号から
＋２次回折光の受光信号を引き算する方法がある。ある
いは、＋２次回折光の受光信号に代えて、記録前の信号
そのもの（半導体レーザの駆動信号）を用いて−２次回
折光の受光信号から引き算することもできる。Since the received light signal of the −2nd-order diffracted light at the time of recording includes a recording signal component in addition to the reproduction signal component, the optimum power adjustment and verification are performed based on the received light signal of the −2nd-order diffracted light. The signal component is removed and only the reproduced signal component is extracted. As a method of removing the recording signal component from the received light signal of the −2nd-order diffracted light, for example, since the received light signal of the + 2nd-order diffracted light tracing on an unrecorded track consists only of the recording signal component, There is a method of subtracting the received light signal of the +2 order diffracted light from. Alternatively, instead of the received light signal of the + 2nd-order diffracted light, the signal itself before recording (the drive signal of the semiconductor laser) may be used to subtract from the received light signal of the −2nd-order diffracted light.
【００１６】以上のように、この発明の光ディスク記録
装置によれば、差動トラッキング方式を用いた高精度の
トラッキングを行いつつ、記録時にリアルタイムでの最
適レーザパワー調整、ベリファイ、ディスク上の傷の予
知等が可能である。As described above, according to the optical disk recording apparatus of the present invention, while performing high-accuracy tracking using the differential tracking method, the optimum laser power adjustment in real time during recording, verification, and Foresight and the like are possible.
【００１７】[0017]
【発明の実施の形態】この発明の実施の形態を以下説明
する。図２はこの発明を適用した光ディスク記録再生装
置１０の概要を示すものである。光ディスク１２は例え
ばＣＤ−ＷＯ規格の追記型ディスクで、スピンドルモー
タ１４によって回転駆動されて、光ヘッド１８で信号の
記録および再生が行われる。Embodiments of the present invention will be described below. FIG. 2 shows an outline of an optical disk recording / reproducing apparatus 10 to which the present invention is applied. The optical disc 12 is, for example, a write-once disc of the CD-WO standard, and is rotationally driven by a spindle motor 14 to record and reproduce signals with an optical head 18.
【００１８】記録信号１６は、例えばＣＤ−ＷＯ規格に
従ってＥＦＭ変調された信号である。レーザ駆動手段２
０は、記録時に光ヘッド１８内の半導体レーザを記録信
号１６に従って駆動して、０次回折光により光ディスク
１２に当該信号の記録（ピットの形成等）を行う。レー
ザ光強度調整手段２２は、記録時に−２次回折光の受光
信号に含まれる再生信号成分のアシンメトリ値を検出し
て、最適値として予め定められたアシンメトリ値が得ら
れるように、書込レーザパワーをリアルタイムで調整す
る。The recording signal 16 is a signal that is EFM-modulated according to, for example, the CD-WO standard. Laser driving means 2
In the case of 0, the semiconductor laser in the optical head 18 is driven in accordance with the recording signal 16 at the time of recording, and the signal is recorded on the optical disc 12 by the 0th-order diffracted light (such as formation of pits). The laser beam intensity adjusting means 22 detects the asymmetry value of the reproduction signal component included in the received light signal of the second-order diffracted light at the time of recording, and sets the write laser power so that an asymmetry value predetermined as an optimum value is obtained. Adjust in real time.
【００１９】ベリファイ手段２４は、記録時に−２次回
折光の受光信号に含まれる再生信号成分ともとの記録信
号とを比較してベリファイを行う。ベリファイの結果エ
ラーが検出された場合には、エラー検出情報を出してエ
ラー検出の表示、記録のやり直し等を行う。The verifying means 24 performs verification by comparing a reproduction signal component included in the received light signal of the -second order diffracted light with the original recording signal at the time of recording. If an error is detected as a result of the verification, error detection information is output to display error detection, perform recording again, and the like.
【００２０】トラッキングサーボ系２６は記録時および
再生時に、±１次回折光および０次回折光の受光信号を
用いて差動プッシュプル法によりトラッキングエラーを
検出して、光ヘッド１８のトラッキング制御を行う。ト
ラック良否判定手段２８は記録時および再生時に＋２次
回折光の受光信号（ＨＦ信号）の異常状態（例えば、Ｈ
Ｆ信号がくびれてエンベロープ信号レベルが大きく上下
動する等）を検出することにより、記録直前のトラック
における傷、指紋、ホコリ、記録膜不良等の欠陥を検出
して、そのトラック上の位置が記録位置（０次回折光の
位置）を通過する間トラックサーボのループゲインを低
下させて、不要なトラック外れを防止する。The tracking servo system 26 detects the tracking error by the differential push-pull method using the received light signals of the ± 1st-order diffracted light and the 0th-order diffracted light at the time of recording and reproduction, and controls the tracking of the optical head 18. The track pass / fail determination means 28 detects an abnormal state of the received light signal (HF signal) (for example, H
(The F signal is constricted and the envelope signal level moves up and down greatly) to detect defects such as scratches, fingerprints, dust, and defective recording film on the track immediately before recording, and the position on the track is recorded. While passing through the position (the position of the zero-order diffracted light), the loop gain of the track servo is reduced to prevent unnecessary off-track.
【００２１】他のサーボ系３０は、記録時および再生時
に０次回折光の受光信号を用いてフォーカスサーボおよ
びスピンドルサーボを行う。また、フィードサーボ（光
ヘッド１８のディスク径方向への移動制御）も行う。再
生手段３２は、再生時に０次回折光の受光信号により光
ディスク１２の記録情報の再生を行い、再生信号３４を
出力する。The other servo system 30 performs focus servo and spindle servo by using a light receiving signal of the 0th-order diffracted light during recording and reproduction. Also, a feed servo (movement control of the optical head 18 in the disk radial direction) is performed. The reproducing means 32 reproduces the recorded information of the optical disk 12 by the light receiving signal of the 0th-order diffracted light at the time of reproducing, and outputs a reproduced signal 34.
【００２２】[0022]
【実施例１】図２の光ヘッド１８内の構造の具体例を図
１に示す。光ヘッド１８は半導体レーザ３６から１本の
レーザ光３８を出射し、コリメータレンズ４０で平行光
に変換し、回折格子４２で５本のビーム（０次回折光４
４、＋１次回折光４５、−１次回折光４６、＋２次回折
光４７、−２次回折光４８）に分ける。この５本のビー
ム４４〜４８は、偏光ビームスプリッタ５０を直進し
て、さらに１／４波長板５２および対物レンズ５４を通
って光ディスク１２の記録面に照射される。Embodiment 1 FIG. 1 shows a specific example of the structure in the optical head 18 of FIG. The optical head 18 emits one laser beam 38 from the semiconductor laser 36, converts the laser beam 38 into parallel light with a collimator lens 40, and converts the five beams (zero-order diffracted light 4
4, + 1st-order diffracted light 45, -1st-order diffracted light 46, + 2nd-order diffracted light 47, and -2nd-order diffracted light 48). The five beams 44 to 48 travel straight through the polarizing beam splitter 50 and further irradiate the recording surface of the optical disk 12 through the quarter-wave plate 52 and the objective lens 54.
【００２３】このとき、図３に示すように０次回折光４
４のビームスポット４４ａは光ディスク１２の１本のト
ラック（グルーブ）５６上に位置し、＋２次回折光４７
のビームスポット４７ａはそれに隣接する１本外側のト
ラック５８上に位置し、＋１次回折光４５のビームスポ
ット４５ａは０次回折光４４のビームスポット４４ａと
＋２次回折光４７のビームスポット４７ａの中間に位置
し、−２次回折光４８のビームスポット４８ａは０次回
折光４４のビームスポット４４ａが位置しているトラッ
ク５６に隣接する１本内側のトラック６０上に位置し、
−１次回折光４６のビームスポット４６ａは０次回折光
４４のビームスポット４４ａと−２次回折光４８のビー
ムスポット４８ａの中間に位置している。これにより、
５個のビームスポット４４ａ〜４８ａは、１／２トラッ
クピッチずつディスク径方向に位置をずらして配置され
る。このようなビームスポット４４ａ〜４８ａの配置
は、回折格子４２の配置（トラック方向に対する格子方
向の角度設定）によって実現される。At this time, as shown in FIG.
The fourth beam spot 44 a is located on one track (groove) 56 of the optical disc 12,
Is located on one outer track 58 adjacent thereto, and the beam spot 45a of the + 1st-order diffracted light 45 is located between the beam spot 44a of the 0th-order diffracted light 44 and the beam spot 47a of the + 2nd-order diffracted light 47. , The beam spot 48a of the second-order diffracted light 48 is located on the inner track 60 adjacent to the track 56 on which the beam spot 44a of the 0th-order diffracted light 44 is located,
The beam spot 46a of the -1st-order diffracted light 46 is located between the beam spot 44a of the 0th-order diffracted light 44 and the beam spot 48a of the -second-order diffracted light 48. This allows
The five beam spots 44a to 48a are arranged with their positions shifted in the radial direction of the disk by a half track pitch. Such an arrangement of the beam spots 44a to 48a is realized by an arrangement of the diffraction grating 42 (setting an angle of the grating direction with respect to the track direction).
【００２４】図１において、５本のレーザ光４４〜４８
の光ディスク１２からの反射光４４ｂ〜４８ｂは、対物
レンズ５４を通って偏光ビームスプリッタ５０で直角に
曲げられ、検出レンズ６２で集束光に変換され、一部が
ハーフミラー６４を直進して光検出器６６で受光され
る。また、他の一部がハーフミラー６４で直角に曲げら
れて、シリンドリカルレンズ６８を通して０次回折光４
４ｂが光検出器７６で受光される。In FIG. 1, five laser beams 44 to 48 are provided.
The reflected lights 44b to 48b from the optical disk 12 pass through the objective lens 54, are bent at a right angle by the polarization beam splitter 50, are converted into condensed light by the detection lens 62, and a part of the reflected light travels straight through the half mirror 64 to perform light detection. The light is received by the device 66. The other part is bent at a right angle by the half mirror 64 and passes through the cylindrical lens 68 so that the zero-order diffracted light 4
4b is received by the photodetector 76.
【００２５】光検出器７６は４分割ＰＩＮフォトダイオ
ードで構成され、フォーカス制御に用いられる。すなわ
ち、４分割光検出器７６は０次回折光４４ｂを受光し、
その４つの受光出力は加算器１０４，１０６で対角位置
の出力どうしが加算され、その結果得られる２つの加算
出力が引算器１０８で引算されて、フォーカスエラー信
号ＦＥが作成される。フォーカスエラー信号ＦＥに基づ
いてフォーカス制御が行われる。The photodetector 76 is composed of a four-division PIN photodiode and is used for focus control. That is, the quadrant photodetector 76 receives the 0th-order diffracted light 44b,
The four light-receiving outputs are added together at diagonal positions by adders 104 and 106, and the resulting two added outputs are subtracted by a subtractor 108 to generate a focus error signal FE. Focus control is performed based on the focus error signal FE.
【００２６】光検出器６６はＰＩＮフォトダイオードで
構成され、中央に０次回折光４４ｂを受光する２分割受
光素子７０を配し、その前後に＋１次回折光４５ｂ、−
１次回折光４６ｂを受光する２分割受光素子７２，７４
を配している。さらにその前後に、＋２次回折光４７
ｂ、−２次回折光４８ｂを受光する無分割受光素子７
６，７８を配している。The photodetector 66 is composed of a PIN photodiode, and a two-divided light receiving element 70 for receiving the 0th-order diffracted light 44b is disposed at the center.
Two-divided light receiving elements 72 and 74 for receiving the first-order diffracted light 46b
Is arranged. Before and after that, the + 2nd-order diffracted light 47
b, a non-segmented light receiving element 7 for receiving the second-order diffracted light 48b
6,78 are arranged.
【００２７】２分割受光素子７０で受光された０次回折
光４４ｂの２つの受光出力は、引算器７８で引算され
て、信号ＴＥm が作成され、また加算器８０で加算され
て信号Ｓo が作成される。２分割受光素子７２で受光さ
れた＋１次回折光４５ｂの２つの受光出力は、引算器８
２で引算されて、信号ＴＥs1が作成される。２分割受光
素子７４で受光された−１次回折光４６ｂの２つの受光
出力は、引算器８４で引算されて、信号ＴＥs1′が作成
される。受光素子７６は＋２次回折光４７ｂを受光し
て、受光信号Ｓ2 を出力する。受光素子７８は−２次回
折光４８ｂを受光して、受光信号Ｓ2 ′を出力する。The two received light outputs of the zero-order diffracted light beam 44b received by the two-divided light receiving element 70 are subtracted by a subtractor 78 to generate a signal TEm, and are added by an adder 80 to add a signal So. Created. The two received light outputs of the + 1st-order diffracted light 45b received by the two-divided light receiving element 72 are divided by the subtractor 8
The signal TEs1 is created by subtraction by 2. The two received light outputs of the -1st-order diffracted light 46b received by the two-divided light receiving element 74 are subtracted by a subtractor 84 to generate a signal TEs1 '. The light receiving element 76 receives the + 2nd-order diffracted light 47b and outputs a light receiving signal S2. The light receiving element 78 receives the second-order diffracted light 48b and outputs a light receiving signal S2 '.
【００２８】これら信号ＴＥm 、Ｓo 、ＴＥs1、ＴＥs
1′、Ｓ2 、Ｓ2 ′の信号処理系統を図４に示す。トラ
ッキングサーボ系２６は、メインスポット（０次回折
光）とサイドスポット（±１次回折光）それぞれのプッ
シュプル信号を検出し、その差をとってトラッキングエ
ラー信号を求める。すなわち、信号ＴＥs1′に対してア
ンプ８３でゲインＧ２を付与し、加算器８５でこれと信
号ＴＥs1を加算し、さらにその加算出力に対しアンプ８
６でゲインＧ１を付与し、引算器８８で信号ＴＥmを引
算して、差動プッシュプル方式によるトラッキングエラ
ー信号ＴＥとして、 ＴＥ＝ＴＥm −Ｇ１（ＴＥs1＋Ｇ２・ＴＥs1′） を出力する。トラッキングサーボ回路９０は、この信号
ＴＥに基づきトラッキング制御を実行する。These signals TEm, So, TEs1, TEs
FIG. 4 shows a signal processing system for 1 ', S2 and S2'. The tracking servo system 26 detects push-pull signals of the main spot (0th-order diffracted light) and side spots (± 1st-order diffracted light), and obtains a tracking error signal by calculating the difference between the push-pull signals. That is, the gain G2 is given to the signal TEs1 'by the amplifier 83 , the signal TEs1 is added to the signal TEs1' by the adder 85 , and the output of the amplifier 8 is added to the added output.
The gain G1 is applied at 6, and the signal TEm is subtracted at the subtractor 88 to output TE = TEm-G1 (TEs1 + G2.TEs1 ') as the tracking error signal TE by the differential push-pull method. The tracking servo circuit 90 performs tracking control based on the signal TE.
【００２９】なお、ゲインＧ１，Ｇ２は、０次回折光４
４ｂ、＋１次回折光４５ｂ、−１次回折光４６ｂの受光
信号レベルを揃えるためのもので、０次回折光４４ｂと
±１次回折光４５ｂ、４６ｂの光量比をＩ0 ：Ｉ1 （＋
１次回折光４５ｂと−１次回折光４６ｂの受光信号レベ
ルは等しいものとする。）とすると、 Ｇ１＝Ｉ0 ／２Ｉ1 Ｇ２＝Ｉ1 ／Ｉ1 ＝１ となる。The gains G1 and G2 correspond to the 0th-order diffracted light 4
This is for equalizing the light receiving signal levels of the 4b, the + 1st-order diffracted light 45b, and the -1st-order diffracted light 46b. The light amount ratio between the 0th-order diffracted light 44b and the ± 1st-order diffracted lights 45b, 46b is represented by I 0 : I 1 (+
The light receiving signal levels of the first-order diffracted light 45b and the -1st-order diffracted light 46b are assumed to be equal. ) And when, and G1 = I 0 / 2I 1 G2 = I 1 / I 1 = 1.
【００３０】トラック良否判定手段２８は、傷検出回路
９４で＋２次回折光の受光信号Ｓ2の異常状態（例え
ば、ＨＦ信号がくびれてエンベロープ信号レベルが大き
く上下動する等）を検出する（例えば、ある基準レベル
を設定して、ＨＦ信号のエンベロープを検出して、検出
されるエンベロープ信号レベルがこの基準レベルを下回
るあるいは上回ることを検出する）ことにより、記録位
置の１トラック前に傷等の欠陥があると判定し、トラッ
キングゲイン調整回路９６により、その欠陥位置が記録
位置を通過するまでの間トラッキングサーボ系２６のル
ープゲインを所定の値に低下させる。The track pass / fail judgment means 28 detects an abnormal state of the received light signal S2 of the + 2nd-order diffracted light (for example, the HF signal is narrowed and the envelope signal level largely moves up and down) by the flaw detection circuit 94 (for example, there is a certain state). A reference level is set, the envelope of the HF signal is detected, and it is detected that the detected envelope signal level is below or above this reference level. It is determined that there is, and the loop gain of the tracking servo system 26 is reduced to a predetermined value by the tracking gain adjustment circuit 96 until the defect position passes the recording position.
【００３１】なお、トラック良否判定手段２８は再生時
にもエラー検出を行って、エラーが検出されたときに、
欠陥位置が０次回折光４４による再生位置を通過するま
での間トラッキングループ２６のゲインを所定の値に低
下させることにより、音飛びその他の再生エラーを防止
することができる。The track pass / fail judgment means 28 also performs error detection during reproduction, and when an error is detected,
By reducing the gain of the tracking loop 26 to a predetermined value until the defect position passes through the reproduction position by the 0th-order diffracted light 44, it is possible to prevent skipping and other reproduction errors.
【００３２】トラックの傷等による＋２次回折光の受光
信号レベルの変化の具体的な例を図９（ａ）〜（ｄ）に
示す。トラックの欠陥としては、ディスクの表面上のも
のとして、傷、指紋付着、ほこり等があり、ディスクの
内部のものとしては、記録膜自身のピンホール欠陥等が
ある。図９（ａ）は、記録時においてディスク内部にピ
ンホール等があった場合であり、反射率が上がってい
る。図９（ｂ）は、記録時においてディスク表面に傷、
指紋、ほこり等があった場合を示し、この場合は反射率
が下がる。図９（ｃ）は、記録時にほこり等が介在した
ため、信号記録がなされなかった部分を再生した場合で
あって、このような場合には、反射率が上がる。また図
９（ｄ）は、再生時にディスク表面に傷、指紋、ほこり
等が存在した場合で、反射率が下がる。FIGS. 9A to 9D show specific examples of changes in the level of the received light signal of the + 2nd-order diffracted light due to a scratch on a track or the like. Track defects include scratches, fingerprints, dust and the like on the surface of the disk, and pinhole defects in the recording film itself and the like inside the disk. FIG. 9A shows a case where a pinhole or the like is present inside the disc during recording, and the reflectance is increased. FIG. 9B shows that the surface of the disc is scratched during recording.
This indicates a case where a fingerprint, dust, or the like is present, and in this case, the reflectance decreases. FIG. 9C shows a case where a portion where signal recording has not been performed is reproduced because dust or the like is interposed at the time of recording. In such a case, the reflectance increases. FIG. 9D shows a case where a scratch, fingerprint, dust, or the like is present on the disk surface during reproduction, and the reflectance is reduced.
【００３３】レーザ光強度調整手段２２は、引算器９８
で−２次回折光の受光信号Ｓ2 ′（記録信号成分と再生
信号成分を含む信号）から＋２次回折光の受光信号Ｓ2
（記録信号成分のみ含む信号）を引算して、再生信号成
分のみからなる信号Ｒすなわち Ｒ＝Ｓ2 ′−Ｓ2 を作成する。この信号Ｒはアシンメトリ測定回路１００
に入力されて、実記録しながらアシンメトリ値が検出さ
れる。アシンメトリ値は図５に示すような−２次回折光
のアイパターンにおいて、＋側の波高値をＡ、−側の波
高値をＢとして、例えば次式により求められる。The laser beam intensity adjusting means 22 includes a subtractor 98
From the received light signal S2 'of the -second order diffracted light (the signal including the recording signal component and the reproduced signal component) to the received light signal S2 of the + 2nd order diffracted light
(A signal containing only a recording signal component) is subtracted to create a signal R consisting of only a reproduction signal component, that is, R = S2'-S2. This signal R is output from the asymmetry measuring circuit 100.
And an asymmetry value is detected while actually recording. The asymmetry value is obtained by, for example, the following equation, where A is the peak value on the + side and B is the peak value on the-side in the eye pattern of the second-order diffracted light as shown in FIG.
【００３４】アシンメトリ値（％）＝｛（Ｂ−Ａ）÷２
（Ｂ＋Ａ）｝×１００ アシンメトリ測定回路１００は波高値Ａ，Ｂを検出し
て、上式によりアシンメトリ値を算出する。Asymmetry value (%) = {(BA)} 2
(B + A)｝ × 100 The asymmetry measuring circuit 100 detects the peak values A and B and calculates the asymmetry value by the above equation.
【００３５】レーザ光強度調整回路１０２は、半導体レ
ーザ３６から出射するレーザ光３８の強度を制御する。
すなわち、記録時は図６（ａ）に示すように、０次回折
光４４が記録に必要な最低限の強度Ｐｗよりも高くな
り、±１次回折光４５，４６、±２次回折光４７，４８
が記録に必要な最低限の強度Ｐｗよりも低く再生に必要
な最低限の強度Ｐｒよりも高くなるようにレーザ光３８
の強度を設定する。また、再生時は図６（ｂ）に示すよ
うに、全回折光４４〜４８がいずれも記録に必要な最低
限の強度Ｐｗよりも低く、再生に必要な最低限の強度Ｐ
ｒよりも高くなるようにレーザ光３８の強度を設定す
る。記録用レーザ光強度の規格値を４〜８ｍＷとし、再
生用レーザ光強度の規格値を０．７ｍＷ未満とした場合
の各回折光の記録時および再生時の強度の一例を次表に
示す（単位はｍＷ）。The laser light intensity adjusting circuit 102 controls the intensity of the laser light 38 emitted from the semiconductor laser 36.
That is, at the time of recording, as shown in FIG. 6A, the 0th-order diffracted light 44 becomes higher than the minimum intensity Pw necessary for recording, and the ± 1st-order diffracted lights 45 and 46 and the ± 2nd-order diffracted lights 47 and 48.
Is lower than the minimum intensity Pw required for recording and higher than the minimum intensity Pr required for reproduction.
Set the intensity of Further, at the time of reproduction, as shown in FIG. 6B, all of the diffracted lights 44 to 48 are lower than the minimum intensity Pw required for recording, and the minimum intensity Pw required for reproduction.
The intensity of the laser light 38 is set to be higher than r. The following table shows an example of the recording and reproducing intensities of each diffracted light when the standard value of the recording laser beam intensity is 4 to 8 mW and the standard value of the reproducing laser beam intensity is less than 0.7 mW ( The unit is mW).
【００３６】 〔再生時〕〔 記 録 時 〕 （１倍速） （２倍速） （４倍速） ０次回折光： 〜０．７ ４〜８ ５．５〜１１ ８〜１６ ±１次回折光： 〜０．７ 〜１ 〜１．５ 〜２ ±２次回折光： 〜０．７ 〜０．７ 〜０．７ 〜０．７[During playback] [During recording](1x speed) (2x speed) (4x speed) 0th order diffracted light: ０．７0.7 4 to 8 5.5 to 118 16 ± 1st order diffracted light: ０．７0.7 1 to 1.5１．５2 ± 2nd order diffracted light: ０．７0.7 to 0.7〜 0.7 to 0.7
【００３７】また、レーザ光強度調整回路１０２は、記
録時にはアシンメトリ測定回路１００で検出されるアシ
ンメトリ値（すなわち、０次回折光４４で記録された光
ディスク１２上の記録部分を次の周回で−２次回折光４
８によって検出した受光信号中の再生信号成分のアシン
メトリ値）が、最適とされるアシンメトリ値（例えば
０．０４）になるように、レーザ光３８の強度をリアル
タイムで微調整する。この微調整には従来のＡＬＰＣ制
御におけるサンプルホールドやＡＤ変換は不要なので回
路構成が簡単で済む。The laser beam intensity adjusting circuit 102 outputs the asymmetry value detected by the asymmetry measuring circuit 100 at the time of recording (that is, the recording portion on the optical disk 12 recorded by the 0th-order diffracted light 44 in the next round -2nd time). Origami 4
The intensity of the laser light 38 is fine-tuned in real time so that the asymmetry value of the reproduction signal component in the received light signal detected by the step 8 becomes the optimum asymmetry value (for example, 0.04). This fine adjustment does not require sample hold and AD conversion in the conventional ALPC control, so that the circuit configuration can be simplified.
【００３８】この微調整は、例えば図７に示すようなフ
ローに従って行うことができる。すなわち、記録開始当
初はレーザ光強度を所定の初期値に設定して（Ｓ１）、
記録を開始する（Ｓ２）。あるいは、予めＯＰＣ動作に
よって最適レーザパワー値を求めて、それを初期値とし
て設定してもよい。記録開始後はアシンメトリ測定回路
１００でアシンメトリ値を検出し（Ｓ３）、最適アシン
メトリ値かどうかを判定し（Ｓ４）、最適アシンメトリ
値から外れている場合はレーザ光強度を調整し（Ｓ
５）、最適アシンメトリ値が得られている時はその時の
レーザ光強度を保持する（Ｓ６）。This fine adjustment can be performed, for example, according to the flow shown in FIG. That is, at the beginning of the recording, the laser beam intensity is set to a predetermined initial value (S1),
Recording is started (S2). Alternatively, the optimum laser power value may be obtained in advance by the OPC operation and set as the initial value. After the start of recording, the asymmetry measurement circuit 100 detects the asymmetry value (S3), determines whether or not the value is the optimal asymmetry value (S4), and adjusts the laser beam intensity when the value is out of the optimal asymmetry value (S3).
5) When the optimum asymmetry value is obtained, the laser beam intensity at that time is held (S6).
【００３９】なお、記録開始当初にＯＰＣ動作を行わず
にレーザ光強度を適切な初期値に設定する方法として
は、例えば次の方法が考えられる。すなわち、未記録デ
ィスクにはディスク種類を識別するためのディスクＩＤ
が予め記録されている。そこで、ディスク種類ごとの最
適記録パワー値の標準値（例えば、ＩＤ＝１（○○社の
××ディスク）のときは６ｍＷ、ＩＤ＝２（△△社の□
□ディスク）のときは７．５ｍＷ等）を記憶したＲＯＭ
等を装置に組み込んでおき、記録時にディスクＩＤを読
み込んでディスク種類を識別し、そのディスクについて
定められた最適パワー値をＲＯＭから読み出して、その
値を初期値として記録を開始する。As a method for setting the laser beam intensity to an appropriate initial value without performing the OPC operation at the beginning of the recording, for example, the following method can be considered. That is, for an unrecorded disc, a disc ID for identifying the disc type is used.
Are recorded in advance. Therefore, a standard value of the optimum recording power value for each disc type (for example, when ID = 1 (XX disc of XX), 6 mW, ID = 2 (□ of △△)
□ ROM for 7.5mW for disk)
The disk ID is read at the time of recording, the type of the disk is identified, the optimum power value determined for the disk is read from the ROM, and recording is started using the value as an initial value.
【００４０】以上のようにして、レーザ光強度調整手段
２２では記録時にリアルタイムでＯＰＣ動作およびＡＬ
ＰＣ動作が実現される。初期値としてディスクＩＤを用
いれば、事前のＯＰＣ動作は不要になる。また、初期値
を事前のＯＰＣ動作で求める場合でも、記録開始後の径
方向位置による最適記録パワー値の変動等に対応できる
効果が得られる。As described above, the laser beam intensity adjusting means 22 performs the OPC operation and the AL operation in real time during recording.
The PC operation is realized. If the disk ID is used as the initial value, the prior OPC operation becomes unnecessary. Further, even when the initial value is obtained by the OPC operation in advance, an effect is obtained that can cope with a change in the optimum recording power value due to the radial position after the start of recording.
【００４１】ベリファイ手段２４はデータ比較回路１１
８で信号Ｒ（再生信号）と信号Ｓo（記録信号）を比較
して、ベリファイを行う。これはＥＦＭ信号どうしを比
較する（ビット列の“１”、“０”を直接対比する。）
ことによって簡単に行うことができる。なお、信号Ｒは
信号Ｓo に対して約１周分遅れて検出されるので、この
遅れ分だけ信号Ｓo を遅延して比較する。また、信号
Ｒ、Ｓo を直接比較するのに代えて、信号Ｒ、Ｓo をそ
れぞれＥＦＭ復調してから比較することもできる。ま
た、記録信号として、信号Ｓo に代えて、記録前の信号
そのもの（半導体レーザの駆動信号あるいはＥＦＭ変調
前のデータ）を用いて比較することもできる。The verifying means 24 is a data comparing circuit 11
At 8, the signal R (reproduced signal) is compared with the signal So (recorded signal) to perform verification. This compares the EFM signals (the bit strings "1" and "0" are directly compared).
This can be done easily. Since the signal R is detected with a delay of about one turn with respect to the signal So, the signal So is delayed by this delay and compared. Further, instead of directly comparing the signals R and So, the signals R and So may be EFM demodulated and then compared. Also, the comparison can be made by using a signal itself before recording (a drive signal of a semiconductor laser or data before EFM modulation) instead of the signal So as a recording signal.
【００４２】[0042]
【実施例２】この発明の他の実施例を図８に示す。図１
の実施例と共通する部分には同一の符号を用いる。この
光ディスク記録再生装置１０′は、光ヘッド１８′の光
検出器６６′内の０次回折光受光素子７０′を４分割Ｐ
ＩＮフォトダイオードで構成して、その受光出力を用い
てフォーカスエラー検出を併せて行うようにしたもので
ある。したがって、前記図１の実施例におけるハーフミ
ラー６４や光検出器７６はここでは省かれ、検出レンズ
６２を出た５本のレーザ光４４ｂ〜４８ｂはそのままシ
リンドリカルレンズ６８を介して光検出器６６′で受光
される。０次回折光４４ｂを受光する４分割フォトダイ
オード７０′のうち、トラック進行方向に対し左側にあ
る２つの受光素子Ａ，Ｄの出力が加算器１１０で加算さ
れ、トラック進行方向に対し右側にある２つの受光素子
Ｂ，Ｃの出力が加算器１１２で加算される。２つの加算
出力は引算器７８で引算されて信号ＴＥm が作成され
る。また、２つの加算出力は加算器８０で加算されて信
号Ｓo が作成される。再生時は信号Ｓo を用いて再生
（データ復調）が行われる。他は実施例１と同じであ
る。Embodiment 2 Another embodiment of the present invention is shown in FIG. FIG.
The same reference numerals are used for the parts common to the embodiments. This optical disk recording / reproducing apparatus 10 'separates the 0th-order diffracted light receiving element 70' in the photodetector 66 'of the optical head 18' into four divided Ps.
It is composed of an IN photodiode, and focus error detection is also performed using the received light output. Therefore, the half mirror 64 and the photodetector 76 in the embodiment of FIG. 1 are omitted here, and the five laser beams 44b to 48b exiting the detection lens 62 are directly passed through the cylindrical lens 68 to the photodetector 66 '. Is received at. The outputs of the two light receiving elements A and D on the left side in the track traveling direction among the four-division photodiodes 70 'that receive the 0th-order diffracted light 44b are added by the adder 110, and the outputs on the right side in the track traveling direction are added. The outputs of the two light receiving elements B and C are added by the adder 112. The two added outputs are subtracted by a subtractor 78 to generate a signal TEm. Further, the two added outputs are added by an adder 80 to generate a signal So. At the time of reproduction, reproduction (data demodulation) is performed using the signal So. Others are the same as the first embodiment.
【００４３】尚、前記実施の形態では、この発明の光ヘ
ッドを光ディスク記録再生装置に適用した場合について
説明したが、光ディスク記録専用装置あるいは光ディス
ク再生専用装置にも適用することができる。光ディスク
再生専用装置に適用する場合には、０次回折光で再生を
行い、０次回折光および±１次回折光で差動プッシュプ
ル法によるトラッキング制御を行い、＋２次回折光で傷
等の欠陥の予知に基づくトラッキングサーボ系のループ
ゲインの切換制御等を行うように構成することができ
る。In the above embodiment, the case where the optical head of the present invention is applied to an optical disk recording / reproducing apparatus has been described. However, the present invention can also be applied to an optical disk recording-only apparatus or an optical disk reproducing-only apparatus. When applied to an optical disk reproduction-only device, reproduction is performed using the 0th-order diffracted light, tracking control is performed by the differential push-pull method using the 0th-order diffracted light and ± 1st-order diffracted light, and the + 2nd-order diffracted light is used to predict defects such as scratches. It can be configured to perform switching control of the loop gain of the tracking servo system based on the control.
【図１】 この発明の実施例を示す光ヘッド内の光学系
の構成を示す図である。FIG. 1 is a diagram illustrating a configuration of an optical system in an optical head according to an embodiment of the present invention.
【図２】 この発明の実施の形態を示す図である。FIG. 2 is a diagram showing an embodiment of the present invention.
【図３】 図１の光ディスクに照射されるレーザ光のビ
ームスポットの配置を示す平面図である。FIG. 3 is a plan view showing an arrangement of a beam spot of a laser beam applied to the optical disc of FIG. 1;
【図４】 図１の光ヘッド１８の受光出力の信号処理系
統の一実施例を示すブロック図である。FIG. 4 is a block diagram showing one embodiment of a signal processing system of a light receiving output of the optical head 18 of FIG.
【図５】 アシンメトリの説明図である。FIG. 5 is an explanatory diagram of asymmetry.
【図６】 図１のビームスポットの配列方向に沿った線
Ｌ上での記録時および再生時のレーザ光強度分布を示す
図である。6 is a diagram showing a laser light intensity distribution during recording and reproduction on a line L along the arrangement direction of the beam spots in FIG. 1;
【図７】 図１のレーザ光強度調整手段２２によるアシ
ンメトリ値の測定に基づくレーザ光強度の制御フローを
示す図である。7 is a diagram showing a control flow of laser light intensity based on measurement of an asymmetry value by the laser light intensity adjusting means 22 in FIG. 1;
【図８】 この発明の他の実施例を示す光ヘッド内の光
学系の構成を示す図である。FIG. 8 is a diagram showing a configuration of an optical system in an optical head according to another embodiment of the present invention.
【図９】 ディスクの傷等による受光信号レベルの変化
例を示す図である。FIG. 9 is a diagram illustrating an example of a change in a light receiving signal level due to a scratch on a disk or the like.
１０，１０′ 光ディスク記録再生装置 １８，１８′ 光ヘッド ２２ レーザ光強度調整手段 ２４ ベリファイ手段 ２６ トラッキングサーボ系 ２８ トラック良否判定手段 ３６ 半導体レーザ ４４ ０次回折光 ４４ａ ０次回折光のビームスポット ４５ ＋１次回折光 ４５ａ ＋１次回折光のビームスポット ４６ −１次回折光 ４６ａ −１次回折光のビームスポット ４７ ＋２次回折光 ４７ａ ＋２次回折光のビームスポット ４８ −２次回折光 ４８ａ −２次回折光のビームスポット ５６，５８，６０ トラック ６６，６６′ 光検出器 １１４，１１４′ 光学系 10, 10 'Optical disk recording / reproducing device 18, 18' Optical head 22 Laser beam intensity adjusting means 24 Verifying means 26 Tracking servo system 28 Track pass / fail determination means 36 Semiconductor laser 44 0th-order diffracted light 44a Beam spot of 0th-order diffracted light 45 + 1st-order diffracted light 45a + 1st-order diffracted light beam spot 46-1st-order diffracted light 46a-1st-order diffracted light beam spot 47 + 2nd-order diffracted light 47a + 2nd-order diffracted light beam spot 48-2nd-order diffracted light 48a-2nd-order diffracted light beam spot 56, 58, 60 tracks 66, 66 'Optical detector 114, 114' Optical system
フロントページの続き (56)参考文献 特開 平１−256022（ＪＰ，Ａ) 特開 平２−247837（ＪＰ，Ａ) 特開 平８−124164（ＪＰ，Ａ) 特開 平５−250720（ＪＰ，Ａ) 特開 平５−101420（ＪＰ，Ａ) 特開 平３−41632（ＪＰ，Ａ) 特開 平７−176073（ＪＰ，Ａ) 特開 平３−127331（ＪＰ，Ａ) 特開 平５−54415（ＪＰ，Ａ) 特開 平８−124166（ＪＰ，Ａ) (58)調査した分野(Int.Cl.7，ＤＢ名) G11B 7/12 - 7/22 G11B 7/0045 Continuation of the front page (56) References JP-A-1-256022 (JP, A) JP-A-2-24737 (JP, A) JP-A-8-124164 (JP, A) JP-A-5-250720 (JP) JP-A-5-101420 (JP, A) JP-A-3-41632 (JP, A) JP-A-7-176073 (JP, A) JP-A-3-127331 (JP, A) 5-54415 (JP, A) JP-A-8-124166 (JP, A) (58) Fields investigated (Int. Cl. 7 , DB name) G11B 7/ 12-7/22 G11B 7/0045
Claims (5)
と、この半導体レーザのレーザ光出射側に配置されて、
当該出射されたレーザ光を０次回折光、＋１、−１次回
折光および＋２、−２次回折光の少なくとも５本の光に
分割する回折格子と、前記０次回折光のビームスポット
が光ディスクの１本のトラック上に位置しているとき
に、前記＋２次回折光のビームスポットがそれに隣接す
る１本外側のトラック上に位置し、前記＋１次回折光の
ビームスポットが前記０次回折光のビームスポットと前
記＋２次回折光のビームスポットの中間に位置し、前記
−２次回折光のビームスポットが前記０次回折光のビー
ムスポットが位置しているトラックに隣接する１本内側
のトラック上に位置し、前記−１次回折光のビームスポ
ットが前記０次回折光のビームスポットと前記−２次回
折光のビームスポットの中間に位置するように、これら
０次回折光、＋１、−１次回折光および＋２、−２次回
折光を光ディスクの記録面に共通に導く光学系と、前記
０次回折光、＋１、−１次回折光および＋２、−２次回
折光、または前記０次回折光、＋１、−１次回折光およ
び−２次回折光のディスクからの各反射光を個別に検出
する複数の受光面を有する光検出器を有する光ヘッドを
用いて、前記レーザ光を記録信号で変調して光ディスク
に照射し、当該ディスクの内周側のトラックから外周側
のトラックに順次記録を行う光ディスク記録装置であっ
て、 前記半導体レーザから出射する記録用レーザ光の強度
を、前記０次回折光が記録に必要な光強度を有し、前記
＋１、−１次回折光および＋２、−２次回折光が記録に
必要な光強度を有さず再生に必要な光強度を有するよう
に調整し、かつ前記０次回折光で実記録を行いながら前
記光検出器で検出される−２次回折光の受光信号に含ま
れる再生信号成分のアシンメトリ値を求めて、所定のア
シンメトリ値が得られるように前記半導体レーザから出
射する記録用レーザ光の強度をリアルタイムで制御する
レーザ光強度調整手段と、 記録時に前記光検出器で検出される０次回折光および＋
１、−１次回折光の受光信号を用いて差動プッシュプル
法によりトラッキングエラーを検出してトラッキング制
御を行うトラッキングサーボ系とを具備してなる光ディ
スク記録装置。1. A semiconductor laser for emitting one laser beam, and disposed on a laser beam emitting side of the semiconductor laser,
A diffraction grating that divides the emitted laser light into at least five lights of 0th-order diffracted light, +1, -1st-order diffracted light, and +2, -2nd- order diffracted light; When located on a track, the beam spot of the + 2nd-order diffracted light is located on the next outer track adjacent to the + 2nd-order diffracted light, and the beam spot of the + 1st-order diffracted light is the same as the beam spot of the 0th-order diffracted light and the + 2nd-order beam. The beam spot of the -2nd-order diffracted light is located on an inner track adjacent to the track on which the beam spot of the 0-order diffracted light is located, which is located in the middle of the beam spot of the folded light, and the -first order diffracted light is the beam spot is a beam spot of the zero-order diffracted light -2 so as to be positioned in the middle of the beam spot of the diffracted light, these zero-order diffracted light, + 1 -1-order diffracted light and the + 2, an optical system for guiding -2 order diffraction light in common to the recording surface of the optical disk, the 0-order diffracted light, + 1, -1 order diffracted light and the + 2, -2 order diffracted light, or the 0-order diffracted light, + 1 Modulating the laser beam with a recording signal using an optical head having a photodetector having a plurality of light receiving surfaces for individually detecting reflected light of the -1st-order diffracted light and -2nd-order diffracted light from the disc; An optical disc recording apparatus that sequentially irradiates the laser beam from the inner circumferential track to the outer circumferential track of the disk, wherein the intensity of the recording laser light emitted from the semiconductor laser is reduced by the 0th-order diffracted light. Having the required light intensity,
The +1 and −1 order diffracted lights and the +2 and −2 order diffracted lights are adjusted so as not to have the light intensity required for recording but to have the light intensity necessary for reproduction, and to perform the actual recording with the 0 order diffracted light. The asymmetry value of the reproduced signal component included in the received light signal of the second-order diffracted light detected by the detector is obtained, and the intensity of the recording laser light emitted from the semiconductor laser is obtained in real time so that a predetermined asymmetry value is obtained. a laser beam intensity adjusting means for controlling, 0-order diffracted light and detected by the photodetector at the time of recording +
An optical disc recording apparatus comprising: a tracking servo system for detecting a tracking error by a differential push-pull method using a light receiving signal of a 1, -1 order diffracted light and performing tracking control.
と、この半導体レーザのレーザ光出射側に配置されて、
当該出射されたレーザ光を０次回折光、＋１、−１次回
折光および＋２、−２次回折光の少なくとも５本の光に
分割する回折格子と、前記０次回折光のビームスポット
が光ディスクの１本のトラック上に位置しているとき
に、前記＋２次回折光のビームスポットがそれに隣接す
る１本外側のトラック上に位置し、前記＋１次回折光の
ビームスポットが前記０次回折光のビームスポットと前
記＋２次回折光のビームスポットの中間に位置し、前記
−２次回折光のビームスポットが前記０次回折光のビー
ムスポットが位置しているトラックに隣接する１本内側
のトラック上に位置し、前記−１次回折光のビームスポ
ットが前記０次回折光のビームスポットと前記−２次回
折光のビームスポットの中間に位置するように、これら
０次回折光、＋１、−１次回折光および＋２、−２次回
折光を光ディスクの記録面に共通に導く光学系と、前記
０次回折光、＋１、−１次回折光および＋２、−２次回
折光、または前記０次回折光、＋１、−１次回折光およ
び＋２次回折光のディスクからの各反射光を個別に検出
する複数の受光面を有する光検出器を有する光ヘッドを
用いて、前記レーザ光を記録信号で変調して光ディスク
に照射し、当該ディスクの内周側のトラックから外周側
のトラックに順次記録を行う光ディスク記録装置であっ
て、 前記半導体レーザから出射する記録用レーザ光の強度
を、前記０次回折光が記録に必要な光強度を有し、前記
＋１、−１次回折光および＋２、−２次回折光が記録に
必要な光強度有さず再生に必要な光強度を有するように
調整するレーザ光強度調整手段と、 記録時に前記光検出器で検出される０次回折光および＋
１、−１次回折光の受光信号を用いて差動プッシュプル
法によりトラッキングエラーを検出してトラッキング制
御を行うトラッキングサーボ系と、 記録時に前記光検出器で検出される＋２次回折光の受光
信号を用いて記録前のトラックの良否の判定を行い、不
良と判定した場合に、そのトラック上の位置が０次回折
光による記録位置を通過する間、前記トラッキングサー
ボ系のループゲインを低下させるトラック良否判定手段
とを具備してなる光ディスク記録装置。2. A semiconductor laser which emits one laser beam, and is arranged on a laser beam emitting side of the semiconductor laser.
A diffraction grating that divides the emitted laser light into at least five lights of 0th-order diffracted light, +1, -1st-order diffracted light, and +2, -2nd- order diffracted light; When located on a track, the beam spot of the + 2nd-order diffracted light is located on the next outer track adjacent to the + 2nd-order diffracted light, and the beam spot of the + 1st-order diffracted light is the same as the beam spot of the 0th-order diffracted light and the + 2nd-order beam. The beam spot of the -2nd-order diffracted light is located on an inner track adjacent to the track on which the beam spot of the 0-order diffracted light is located, which is located in the middle of the beam spot of the folded light, and the -first order diffracted light is the beam spot is a beam spot of the zero-order diffracted light -2 so as to be positioned in the middle of the beam spot of the diffracted light, these zero-order diffracted light, + 1 -1-order diffracted light and the + 2, an optical system for guiding -2 order diffraction light in common to the recording surface of the optical disk, the 0-order diffracted light, + 1, -1 order diffracted light and the + 2, -2 order diffracted light, or the 0-order diffracted light, + 1 The laser beam is modulated by a recording signal using an optical head having a photodetector having a plurality of light receiving surfaces for individually detecting each reflected light of the -1st-order diffracted light and the + 2nd-order diffracted light from the disc. An optical disc recording apparatus for irradiating and sequentially recording from an inner track to an outer track of the disk, wherein the intensity of a recording laser beam emitted from the semiconductor laser is required for recording by the 0th-order diffracted light. Light intensity, said
Laser light intensity adjusting means for adjusting the +1 and −1 order diffracted lights and the +2 and −2 order diffracted lights so as not to have the light intensity required for recording but to have the light intensity necessary for reproduction; and the light detector detects during recording. 0th order diffracted light and +
A tracking servo system for detecting a tracking error by a differential push-pull method using the light receiving signals of the first and first order diffracted lights and performing tracking control; and a light receiving signal of the +2 order diffracted light detected by the photodetector during recording. using performs quality determination of the track before recording it, if it is determined to be defective, the position on the track zero-order diffraction
An optical disc recording apparatus comprising: track pass / fail determination means for reducing a loop gain of the tracking servo system while passing through a recording position by light .
と、この半導体レーザのレーザ光出射側に配置されて、
当該出射されたレーザ光を０次回折光、＋１、−１次回
折光および＋２、−２次回折光の少なくとも５本の光に
分割する回折格子と、前記０次回折光のビームスポット
が光ディスクの１本のトラック上に位置しているとき
に、前記＋２次回折光のビームスポットがそれに隣接す
る１本外側のトラック上に位置し、前記＋１次回折光の
ビームスポットが前記０次回折光のビームスポットと前
記＋２次回折光のビームスポットの中間に位置し、前記
−２次回折光のビームスポットが前記０次回折光のビー
ムスポットが位置しているトラックに隣接する１本内側
のトラック上に位置し、前記−１次回折光のビームスポ
ットが前記０次回折光のビームスポットと前記−２次回
折光のビームスポットの中間に位置するように、これら
０次回折光、＋１、−１次回折光および＋２、−２次回
折光を光ディスクの記録面に共通に導く光学系と、前記
０次回折光、＋１、−１次回折光および＋２、−２次回
折光のディスクからの各反射光を個別に検出する複数の
受光面を有する光検出器を有する光ヘッドを用いて、前
記レーザ光を記録信号で変調して光ディスクに照射し、
当該ディスクの内周側のトラックから外周側のトラック
に順次記録を行う光ディスク記録装置であって、 前記半導体レーザから出射する記録用レーザ光の強度
を、前記０次回折光が記録に必要な光強度を有し、前記
＋１、−１次回折光および＋２、−２次回折光が記録に
必要な光強度を有さず再生に必要な光強度を有するよう
に調整し、かつ前記０次回折光で実記録を行いながら前
記光検出器で検出される−２次回折光の受光信号に含ま
れる再生信号成分のアシンメトリ値を求めて、所定のア
シンメトリ値が得られるように前記半導体レーザから出
射する記録用レーザ光の強度をリアルタイムで制御する
レーザ光強度調整手段と、 記録時に前記光検出器で検出される０次回折光および＋
１、−１次回折光の受光信号を用いて差動プッシュプル
法によりトラッキングエラーを検出してトラッキング制
御を行うトラッキングサーボ系と、 記録時に前記光検出器で検出される＋２次回折光の受光
信号を用いて記録前のトラックの良否の判定を行い、不
良と判定した場合に、そのトラック上の位置が０次回折
光による記録位置を通過する間、前記トラッキングサー
ボ系のループゲインを低下させるトラック良否判定手段
とを具備してなる光ディスク記録装置。3. A semiconductor laser which emits one laser beam, and is arranged on a laser beam emitting side of the semiconductor laser.
A diffraction grating that divides the emitted laser light into at least five lights of 0th-order diffracted light, +1, -1st-order diffracted light, and +2, -2nd- order diffracted light; When located on a track, the beam spot of the + 2nd-order diffracted light is located on the next outer track adjacent to the + 2nd-order diffracted light, and the beam spot of the + 1st-order diffracted light is the same as the beam spot of the 0th-order diffracted light and the + 2nd-order diffracted light. The beam spot of the -2nd-order diffracted light is located on an inner track adjacent to the track on which the beam spot of the 0-order diffracted light is located, which is located in the middle of the beam spot of the folded light, and the -first order diffracted light is the beam spot is a beam spot of the zero-order diffracted light -2 so as to be positioned in the middle of the beam spot of the diffracted light, these zero-order diffracted light, + 1 -1-order diffracted light and the + 2, an optical system for guiding -2 order diffraction light in common to the recording surface of the optical disk, the 0-order diffracted light, + 1, -1 order diffracted light and the + 2, -2 respective reflected light from the disc-order diffracted light Using an optical head having a photodetector having a plurality of light receiving surfaces to be individually detected, irradiating an optical disc by modulating the laser beam with a recording signal,
What is claimed is: 1. An optical disk recording apparatus for sequentially recording information from an inner track to an outer track of the disk, wherein the intensity of the recording laser light emitted from the semiconductor laser is determined by the light intensity required for recording by the zero-order diffracted light. Having the above
The +1 and −1 order diffracted lights and the +2 and −2 order diffracted lights are adjusted so as not to have the light intensity required for recording but to have the light intensity necessary for reproduction, and to perform the actual recording with the 0 order diffracted light. The asymmetry value of the reproduced signal component included in the received light signal of the second-order diffracted light detected by the detector is obtained, and the intensity of the recording laser light emitted from the semiconductor laser is obtained in real time so that a predetermined asymmetry value is obtained. a laser beam intensity adjusting means for controlling, 0-order diffracted light and detected by the photodetector at the time of recording +
A tracking servo system for detecting a tracking error by a differential push-pull method using the light receiving signals of the first and first order diffracted lights and performing tracking control; and a light receiving signal of the +2 order diffracted light detected by the photodetector during recording. using performs quality determination of the track before recording it, if it is determined to be defective, the position on the track zero-order diffraction
An optical disc recording apparatus comprising: track pass / fail determination means for reducing a loop gain of the tracking servo system while passing through a recording position by light .
と、この半導体レーザのレーザ光出射側に配置されて、
当該出射されたレーザ光を０次回折光、＋１、−１次回
折光および＋２、−２次回折光の少なくとも５本の光に
分割する回折格子と、前記０次回折光のビームスポット
が光ディスクの１本のトラック上に位置しているとき
に、前記＋２次回折光のビームスポットがそれに隣接す
る１本外側のトラック上に位置し、前記＋１次回折光の
ビームスポットが前記０次回折光のビームスポットと前
記＋２次回折光のビームスポットの中間に位置し、前記
−２次回折光のビームスポットが前記０次回折光のビー
ムスポットが位置しているトラックに隣接する１本内側
のトラック上に位置し、前記−１次回折光のビームスポ
ットが前記０次回折光のビームスポットと前記−２次回
折光のビームスポットの中間に位置するように、これら
０次回折光、＋１、−１次回折光および＋２、−２次回
折光を光ディスクの記録面に共通に導く光学系と、前記
０次回折光、＋１、−１次回折光および＋２、−２次回
折光のディスクからの各反射光を個別に検出する複数の
受光面を有する光検出器を有する光ヘッドを用いて、前
記レーザ光を記録信号で変調して光ディスクに照射し、
当該ディスクの内周側のトラックから外周側のトラック
に順次記録を行う光ディスク記録装置であって、 前記半導体レーザから出射する記録用レーザ光の強度
を、前記０次回折光が記録に必要な光強度を有し、前記
＋１、−１次回折光および＋２、−２次回折光が記録に
必要な光強度を有さず再生に必要な光強度を有するよう
に調整し、かつ前記０次回折光で実記録を行いながら前
記光検出器で検出される−２次回折光の受光信号に含ま
れる再生信号成分のアシンメトリ値を求めて、所定のア
シンメトリ値が得られるように前記半導体レーザから出
射する記録用レーザ光の強度をリアルタイムで制御する
レーザ光強度調整手段と、 記録時に前記光検出器で検出される０次回折光および＋
１、−１次回折光の受光信号を用いて差動プッシュプル
法によりトラッキングエラーを検出してトラッキング制
御を行うトラッキングサーボ系と、 記録時に前記光検出器で検出される−２次回折光の受光
信号に含まれる再生信号成分ともとの記録信号とを比較
して、光ディスクに記録されたデータのベリファイを行
うベリファイ手段と、 記録時に前記光検出器で検出される＋２次回折光の受光
信号を用いて記録前のトラックの良否の判定を行い、不
良と判定した場合に、そのトラック上の位置が０次回折
光による記録位置を通過する間、前記トラッキングサー
ボ系のループゲインを低下させるトラック良否判定手段
とを具備してなる光ディスク記録装置。4. A semiconductor laser for emitting one laser beam, and disposed on a laser beam emitting side of the semiconductor laser.
A diffraction grating that divides the emitted laser light into at least five lights of 0th-order diffracted light, +1, -1st-order diffracted light, and +2, -2nd- order diffracted light; When located on a track, the beam spot of the + 2nd-order diffracted light is located on the next outer track adjacent to the + 2nd-order diffracted light, and the beam spot of the + 1st-order diffracted light is the same as the beam spot of the 0th-order diffracted light and the + 2nd-order diffracted light. The beam spot of the -2nd-order diffracted light is located on an inner track adjacent to the track on which the beam spot of the 0-order diffracted light is located, which is located in the middle of the beam spot of the folded light, and the -first order diffracted light is the beam spot is a beam spot of the zero-order diffracted light -2 so as to be positioned in the middle of the beam spot of the diffracted light, these zero-order diffracted light, + 1 -1-order diffracted light and the + 2, an optical system for guiding -2 order diffraction light in common to the recording surface of the optical disk, the 0-order diffracted light, + 1, -1 order diffracted light and the + 2, -2 respective reflected light from the disc-order diffracted light Using an optical head having a photodetector having a plurality of light receiving surfaces to be individually detected, irradiating an optical disc by modulating the laser beam with a recording signal,
What is claimed is: 1. An optical disk recording apparatus for sequentially recording information from an inner track to an outer track of the disk, wherein the intensity of the recording laser light emitted from the semiconductor laser is determined by the light intensity required for recording by the zero-order diffracted light. Having the above
The +1 and −1 order diffracted lights and the +2 and −2 order diffracted lights are adjusted so as not to have the light intensity required for recording but to have the light intensity necessary for reproduction, and to perform the actual recording with the 0 order diffracted light. The asymmetry value of the reproduced signal component included in the received light signal of the second-order diffracted light detected by the detector is obtained, and the intensity of the recording laser light emitted from the semiconductor laser is obtained in real time so that a predetermined asymmetry value is obtained. a laser beam intensity adjusting means for controlling, 0-order diffracted light and detected by the photodetector at the time of recording +
A tracking servo system for detecting a tracking error by a differential push-pull method using the light receiving signals of the first and first order diffracted lights and performing tracking control; and a light receiving signal of the second order diffracted light detected by the photodetector at the time of recording. Verifying means for verifying data recorded on the optical disc by comparing a reproduced signal component contained in the optical disc with the original recorded signal, and a received light signal of +2 order diffracted light detected by the photodetector at the time of recording. The quality of the track before recording is determined, and if it is determined that the track is defective, the position on the track is 0-order diffraction.
An optical disc recording apparatus comprising: track pass / fail determination means for reducing a loop gain of the tracking servo system while passing through a recording position by light .
および＋１、−１次回折光の受光信号のそれぞれのプッ
シュプル信号を検出し、＋１、−１次回折光のプッシュ
プル信号どうしを加算し、これと０次回折光のプッシュ
プル信号とを引算して前記トラッキングエラーを検出す
るものである請求項１から４のいずれかに記載の光ディ
スク記録装置。Wherein said tracking servo system, 0-order diffracted light and the + 1, -1 and detecting each of the push-pull signal of the light receiving signal of the order diffracted light, + 1, -1 by adding the push-pull signal with each other in order diffracted light, which 5. The optical disc recording apparatus according to claim 1, wherein the tracking error is detected by subtracting a push-pull signal of a zero-order diffracted light from the tracking error.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27757196A JP3277824B2 (en) | 1996-09-27 | 1996-09-27 | Optical head and optical disk recording device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP27757196A JP3277824B2 (en) | 1996-09-27 | 1996-09-27 | Optical head and optical disk recording device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH10106018A JPH10106018A (en) | 1998-04-24 |
| JP3277824B2 true JP3277824B2 (en) | 2002-04-22 |
Family
ID=17585353
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP27757196A Expired - Fee Related JP3277824B2 (en) | 1996-09-27 | 1996-09-27 | Optical head and optical disk recording device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3277824B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002100060A (en) * | 2000-09-27 | 2002-04-05 | Matsushita Electric Ind Co Ltd | Photodetector for recorder-reproducer and light receiving circuit |
| JP2002216372A (en) * | 2001-01-23 | 2002-08-02 | Pioneer Electronic Corp | Optical pickup device |
-
1996
- 1996-09-27 JP JP27757196A patent/JP3277824B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH10106018A (en) | 1998-04-24 |
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