JPH07192343A - Recorded signal reproducing method for optical recording medium - Google Patents
Recorded signal reproducing method for optical recording mediumInfo
- Publication number
- JPH07192343A JPH07192343A JP33070793A JP33070793A JPH07192343A JP H07192343 A JPH07192343 A JP H07192343A JP 33070793 A JP33070793 A JP 33070793A JP 33070793 A JP33070793 A JP 33070793A JP H07192343 A JPH07192343 A JP H07192343A
- Authority
- JP
- Japan
- Prior art keywords
- signal
- recording medium
- reproduced
- same
- time difference
- 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.)
- Pending
Links
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は、光記録媒体の記録信
号再生方法、特に光ディスクの記録信号再生方法に関す
るものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording signal reproducing method for an optical recording medium, and more particularly to a recording signal reproducing method for an optical disc.
【０００２】[0002]
【従来の技術】従来、コンパクトディスクなどの再生専
用光ディスクにおける記録信号再生方法は、単に記録ト
ラック上に一つのレーザースポットをトレースさせ、ピ
ットの位置あるいは長さをレーザー光の回折や干渉の原
理を利用して反射光の強弱として読みとり、それを光検
出器で電気信号に置き換えることで再生信号出力を得て
いた。2. Description of the Related Art Conventionally, in a recording signal reproducing method for a reproduction-only optical disk such as a compact disk, one laser spot is simply traced on a recording track and the pit position or length is determined by the principle of laser light diffraction or interference. The read signal output was obtained by reading the intensity of the reflected light as an intensity and replacing it with an electrical signal at the photodetector.
【０００３】[0003]
【発明が解決しようとする課題】しかしながら、このよ
うな従来の記録信号再生方法では、レーザー雑音、電気
回路の雑音、レーザービームの位置制御（フォーカス、
トラッキングサーボ制御）の乱れなどにより、いわゆる
ランダム性のエラーが発生し、媒体上の記録品質が良好
でないときや、記録密度を高くし信号検出の時間的なマ
ージンを狭めた場合などには、エラーレートが悪化する
という問題があった。However, in such a conventional recording signal reproducing method, laser noise, electric circuit noise, and laser beam position control (focus, focus,
An error of so-called randomness occurs due to disturbance of (tracking servo control), and when the recording quality on the medium is not good, or when the recording density is increased and the time margin of signal detection is narrowed, an error occurs. There was a problem that the rate deteriorated.
【０００４】[0004]
【課題を解決するための手段】本発明による光記録媒体
の記録信号再生方法では、光録媒体の情報再生時に、同
一トラック上に複数の信号読みとりレーザースポットを
間隔をおいて配置し、同じ信号を時間差をおいて再生
し、その複数の読みだし信号を遅延回路を用いて読みだ
し時間差を補正し、複数の同一再生信号を得て、その後
各信号の値より、最も確からしい信号を再生信号出力と
することにより、上述した問題点の解決を達成してい
る。同一トラック上に配置する複数のレーザースポット
は、光ヘッド内のレーザービームを光ヘッド中に配置し
た回折格子を用いてビーム分割して、あるいはマルチレ
ーザーダイオードアレーを用いて実現する。In the method of reproducing a recording signal of an optical recording medium according to the present invention, a plurality of signal reading laser spots are arranged at intervals on the same track when reproducing information on the optical recording medium, and the same signal is reproduced. Are reproduced with a time lag, the multiple read signals are read using a delay circuit, the time differences are corrected, a plurality of identical read signals are obtained, and then the most probable signal is reproduced from the value of each signal. The output solves the above-mentioned problems. A plurality of laser spots arranged on the same track are realized by dividing a laser beam in an optical head using a diffraction grating arranged in the optical head or using a multi-laser diode array.
【０００５】[0005]
【作用】この発明によると、光記録媒体に記録されてい
る信号の再生時において、光ヘッド内の回折格子や、レ
ーザーダイオードアレーにより媒体の読みだしトラック
上に複数の読みだしレーザースポットを間隔をおいて配
置している。本発明で用いる光ヘッドは、信号読みだし
用の光検出器を読みだしレーザースポット数と同じ数有
しており、これにより同じ信号を時間差をおいて再生
し、その複数の読みだし信号を遅延回路を用いて読みだ
し時間差を補正し、複数の同一再生信号を得ている。そ
の後各信号の値の平均値や多数値により、最も確からし
い信号を再生信号出力とすることでランダム性のエラー
の影響のきわめて少ない信号再生を行っている。According to the present invention, at the time of reproducing a signal recorded on the optical recording medium, a plurality of reading laser spots are formed on the reading track of the medium by the diffraction grating in the optical head or the laser diode array. I have placed it. The optical head used in the present invention has the same number of photodetectors for reading out signals as the number of laser spots for reading out, thereby reproducing the same signals with a time difference and delaying the plurality of reading signals. A circuit is used to correct the read time difference to obtain a plurality of identical reproduction signals. After that, the most probable signal is output as the reproduction signal by using the average value or the large value of the values of the respective signals, thereby performing the signal reproduction with very little influence of the random error.
【０００６】[0006]
【実施例】図１は本発明の一実施例を示すブロック図で
ある。図２は記録媒体上の再生レーザービームの配置位
置を示す説明図である。図３は実時間における複数ビー
ムによる再生信号、およびそのとき発生したレーザーノ
イズによるランダム性エラーの位置を示す説明図であ
る。図４は信号の読みだし時間差を補正した後の再生信
号およびランダム性エラーの位置を示した説明図であ
る。図５、６は図１のブロック図中の信号処理回路の構
成例を示す図である。FIG. 1 is a block diagram showing an embodiment of the present invention. FIG. 2 is an explanatory view showing the arrangement position of the reproduction laser beam on the recording medium. FIG. 3 is an explanatory diagram showing a reproduced signal by a plurality of beams in real time and a position of a random error due to laser noise generated at that time. FIG. 4 is an explanatory diagram showing the positions of the reproduced signal and the randomness error after the signal reading time difference is corrected. 5 and 6 are diagrams showing a configuration example of the signal processing circuit in the block diagram of FIG.
【０００７】これらの図を参照して本発明の一実施例に
ついて説明する。図１の半導体レーザー１からの出射光
はコリメータレンズ２でコリメート光に変換され、回折
格子３を通り、対物レンズ５でディスク６上に集光され
集光スポット７ａ〜７ｃを形成する。ここで半導体レー
ザー１がレーザーダイオードアレーにより、もともと複
数のレーザービームを出射する場合は、回折格子３は不
要である。An embodiment of the present invention will be described with reference to these drawings. Light emitted from the semiconductor laser 1 of FIG. 1 is converted into collimated light by the collimator lens 2, passes through the diffraction grating 3, and is condensed on the disk 6 by the objective lens 5 to form condensed spots 7a to 7c. Here, when the semiconductor laser 1 originally emits a plurality of laser beams by the laser diode array, the diffraction grating 3 is unnecessary.
【０００８】この際、集光スポット７ａ〜７ｃは、図２
に示すように媒体面上の同一トラックに、間隔をおいて
ビームスポットが配置されるようにする。ここでは簡単
のためスポット数が３個の場合について説明する。At this time, the focused spots 7a to 7c are shown in FIG.
The beam spots are arranged on the same track on the medium surface at intervals as shown in FIG. Here, for simplicity, a case where the number of spots is 3 will be described.
【０００９】ディスク６からの反射回折光はふたたび対
物レンズ５で集められ、ビームスプリッタ４に至り、集
光レンズ８側に導かれる。そして再び集光された反射回
折光は、光検出器９ａ〜９ｃ上で受光され、電気信号に
変換される。光検出器９からの電気信号は、通常電流信
号であるので、電流電圧変換アンプ１０ａ〜１０ｃによ
り、電圧信号に変換される。The reflected diffracted light from the disk 6 is collected again by the objective lens 5, reaches the beam splitter 4, and is guided to the condenser lens 8 side. The reflected and diffracted light that has been condensed again is received on the photodetectors 9a to 9c and converted into an electric signal. Since the electric signal from the photodetector 9 is a normal current signal, it is converted into a voltage signal by the current-voltage conversion amplifiers 10a to 10c.
【００１０】このときの３系統の再生信号は、図２に示
すように各集光スポットの位置が異なるため、時間差を
持った同一内容の信号となる。そのため図３に示すよう
に、この時レーザーノイズやサーボ系の不調等による影
響は、各再生系に同時に影響し、図に示すような実時間
上で同一箇所のエラーとなる。At this time, the reproduced signals of the three systems have the same contents with a time difference because the positions of the respective focused spots are different as shown in FIG. Therefore, as shown in FIG. 3, at this time, the influence of the laser noise or the malfunction of the servo system affects each reproducing system at the same time, resulting in an error at the same location in real time as shown in the figure.
【００１１】各再生信号は、信号遅延回路１１ａ〜１１
ｂにより、各信号の再生時間差および位相を一致させ
る。この信号遅延回路を通過した後の再生信号列は、頭
４に示すようになり、それぞれのエラー発生箇所は時間
軸上で、図に示すように分散される。Each of the reproduced signals has a signal delay circuit 11a-11.
By b, the reproduction time difference and the phase of each signal are matched. The reproduced signal sequence after passing through this signal delay circuit is as shown in the head 4, and the respective error occurrence points are dispersed as shown in the figure on the time axis.
【００１２】これらの信号は信号処理回路１２で処理さ
れてエラーの抑制された再生信号１３を出力する。この
信号処理回路１２はアナログ信号の場合は、たとえば加
算平均などによる処理を、デジタル信号では、多数決判
定などの処理を行う。この部分は使用する媒体の特性や
扱う信号の性質などによりさまざまな処理が考えられ
る。These signals are processed by the signal processing circuit 12 to output a reproduction signal 13 in which errors are suppressed. In the case of an analog signal, the signal processing circuit 12 performs processing such as averaging, and for a digital signal, processing such as majority decision. Various processing can be considered for this part depending on the characteristics of the medium used and the characteristics of the signal to be handled.
【００１３】図５にアナログ信号の場合の信号処理回路
１２の構成例を示す。各再生信号は加算器１４にて加算
平均され、１つの信号中にエラーがあっても、残り２つ
の信号の同一時間上にエラーがないため、加算器出力は
このエラーの影響が低減された信号とすることができ
る。FIG. 5 shows a configuration example of the signal processing circuit 12 in the case of an analog signal. Each reproduction signal is added and averaged by the adder 14, and even if there is an error in one signal, there is no error on the same time of the remaining two signals, so the adder output has the influence of this error reduced. It can be a signal.
【００１４】また図６にデジタル処理をする場合の信号
処理回路の構成例を示す。各再生信号は、二値化回路１
５で、“１”、“０”のデジタル信号に変換される。そ
して各二値化再生信号は、半加算器１６ａ〜１６ｃによ
って構成された３入力多数決判定回路により演算され、
状態“１”あるいは“０”のどちらか多い方の状態が再
生信号状態としてＳ１より出力される。図６の回路の真
理値表を図７に示した。ここで問題にしているランダム
性のエラーは、発生位置の固定した媒体の欠陥によるエ
ラーと違って、発生するディスク面上の位置や再生時間
は確率で表される不特定なエラーである。本発明では、
同じ情報記録位置を複数回、複数読みだしスポットを用
いて時間差をおいて読みだし、その平均値をとったり、
デジタル信号なら多数決判定をすることにより、ランダ
ム性エラーが発生しても、その信号の誤りをそのほかの
ビームスポットによる信号で訂正する一種の誤り訂正を
行うことで、実際にエラーとなる確率を大幅に抑制して
いる。ここでは、簡単のため読みだしビームスポット数
を３個に限って説明したが、もちろんスポット数が２個
以上であれば実現可能な範囲で何個あってもかまわな
い。FIG. 6 shows an example of the configuration of a signal processing circuit for digital processing. Each reproduction signal is a binarization circuit 1.
At 5, it is converted into digital signals of "1" and "0". Then, each binarized reproduction signal is calculated by a three-input majority decision circuit composed of half adders 16a to 16c,
The state, whichever is more, "1" or "0", is output from S1 as the reproduction signal state. The truth table of the circuit of FIG. 6 is shown in FIG. The error of randomness, which is a problem here, is an unspecified error in which the position on the disk surface and the reproduction time are represented by probability, unlike the error due to the defect of the medium in which the generation position is fixed. In the present invention,
Reading the same information recording position multiple times with multiple reading spots with a time lag, and taking the average value,
Even if a random error occurs by making a majority decision for digital signals, a kind of error correction is performed to correct the error of that signal with the signal of other beam spots, and the probability of actually becoming an error is greatly increased. Is suppressed. Here, the number of read-out beam spots is limited to three for the sake of simplification, but of course, any number of beam spots may be realized as long as the number of spots is two or more.
【００１５】[0015]
【発明の効果】本発明による、媒体のＳ／Ｎ比が良好で
ない時や、記録密度を高くし信号検出の時間的なマージ
ンを狭めた時でも、信号読みだし誤りの少ない光記録媒
体の信号再生器を提供できるという効果がある。According to the present invention, even when the S / N ratio of the medium is not good, or when the recording density is increased and the time margin of signal detection is narrowed, the signal of the optical recording medium with few signal reading errors is obtained. The effect is that a regenerator can be provided.
【図１】本発明の一実施例を示すブロック図である。FIG. 1 is a block diagram showing an embodiment of the present invention.
【図２】記録媒体上の再生レーザービームの配置位置を
示す図である。FIG. 2 is a diagram showing an arrangement position of a reproduction laser beam on a recording medium.
【図３】実時間における複数ビームによる再生信号、お
よびそのとき発生したレーザーノイズによるランダム性
エラーの位置を示す図である。FIG. 3 is a diagram showing a reproduced signal by a plurality of beams in real time and a position of a random error due to laser noise generated at that time.
【図４】信号の読みだし時間差を補正した後の再生信号
およびランダム性エラーの位置を示した図である。FIG. 4 is a diagram showing a position of a reproduction signal and a randomness error after correcting a signal reading time difference.
【図５】信号処理回路１２の第１の構成例を示す図であ
る。5 is a diagram showing a first configuration example of a signal processing circuit 12. FIG.
【図６】信号処理回路１２の第２の構成例を示す図であ
る。FIG. 6 is a diagram showing a second configuration example of the signal processing circuit 12.
【図７】図６の信号処理回路の真理値表を示す。7 shows a truth table of the signal processing circuit of FIG.
１ 半導体レーザー ２ コリメータレンズ ３ 回折格子 ４ ビームスプリッタ ５ 対物レンズ ６ ディスク ７ａ〜７ｃ 集光スポット ８ 集光レンズ ９ａ〜９ｃ 光検出器 １０ａ〜１０ｂ 電流電圧変換アンプ １１ａ〜１１ｂ 遅延回路 １２ 信号処理回路 １３ 再生信号 １４ アナログ加算器 １５ａ〜１５ｃ 二値化回路 ０６ａ〜１６ｃ 半加算器 DESCRIPTION OF SYMBOLS 1 semiconductor laser 2 collimator lens 3 diffraction grating 4 beam splitter 5 objective lens 6 disk 7a-7c condensing spot 8 condensing lens 9a-9c photodetector 10a-10b current-voltage conversion amplifier 11a-11b delay circuit 12 signal processing circuit 13 Playback signal 14 Analog adder 15a to 15c Binarization circuit 06a to 16c Half adder
Claims (8)
ク上に複数の信号読みとりレーザースポットを間隔をお
いて配置し、同じ信号を時間差をおいて再生することを
特徴とする光記録媒体の記録信号再生方法。1. When recording information on an optical recording medium, a plurality of signal reading laser spots are arranged at intervals on the same track, and the same signal is reproduced with a time difference, thereby recording on the optical recording medium. Signal reproduction method.
複数の読みだし信号を遅延回路を用いて読みだし時間差
を補正し、複数の同一再生信号を得ることを特徴とした
光記録媒体の記録信号再生方法。2. An optical recording medium characterized in that a plurality of read signals according to claim 1, which are reproduced at a time difference, are read by a delay circuit to correct the read time difference to obtain a plurality of identical reproduced signals. Recording signal reproduction method.
を再生信号出力とすることを特徴とする光記録媒体の記
録信号再生方法。3. A recording signal reproducing method for an optical recording medium, wherein an average value of a plurality of the same signals according to claim 2 is used as a reproduction signal output.
れ定数倍してから加算平均し、再生信号出力とすること
を特徴とした光記録媒体の記録信号再生方法。4. A recording signal reproducing method for an optical recording medium, wherein a plurality of the same signals according to claim 2 are each multiplied by a constant and then added and averaged to obtain a reproduction signal output.
れ量子化し、その結果を多数決判定し情報を再生するこ
とを特徴とする光記録媒体の記録信号再生方法。5. A recording signal reproducing method for an optical recording medium, which comprises quantizing each of a plurality of the same signals according to claim 2, and judging the result by majority judgment to reproduce information.
中に配置した回折格子を用いてビーム分割し、複数のレ
ーザースポットを作成し、同一トラック上の同じ信号を
時間差をおいて再生することを特徴とする請求項１記載
の光記録媒体の記録信号再生方法。6. A laser beam in an optical head is divided into beams by using a diffraction grating arranged in the optical head, a plurality of laser spots are created, and the same signal on the same track is reproduced with a time difference. The method for reproducing a recording signal from an optical recording medium according to claim 1, wherein the recording signal is reproduced.
て、複数のレーザースポットを作成し、同一トラック上
の同じ信号を時間差をおいて再生することを特徴とする
請求項１記載の記録媒体の記録信号再生方法。7. The recording signal reproduction of a recording medium according to claim 1, wherein a plurality of laser spots are created by using a multi-laser diode array and the same signal on the same track is reproduced with a time difference. Method.
の複数の光検出器を備えた光ヘッドを用いて同一記録信
号の時間差読みだしを行うことを特徴とした請求項１記
載の光記録媒体の記録信号再生方法。8. The optical recording medium according to claim 1, wherein the time difference reading of the same recording signal is performed using an optical head having a plurality of photodetectors for detecting a plurality of reading laser beams. Recording signal reproduction method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33070793A JPH07192343A (en) | 1993-12-27 | 1993-12-27 | Recorded signal reproducing method for optical recording medium |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP33070793A JPH07192343A (en) | 1993-12-27 | 1993-12-27 | Recorded signal reproducing method for optical recording medium |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH07192343A true JPH07192343A (en) | 1995-07-28 |
Family
ID=18235669
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP33070793A Pending JPH07192343A (en) | 1993-12-27 | 1993-12-27 | Recorded signal reproducing method for optical recording medium |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH07192343A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2004053862A1 (en) * | 2002-12-12 | 2004-06-24 | Pioneer Corporation | Information recording/reading head and information recording/reproducing device |
| US8630157B2 (en) | 2010-08-30 | 2014-01-14 | Kabushiki Kaisha Toshiba | Data reproducing apparatus |
| CN113744766A (en) * | 2020-05-29 | 2021-12-03 | 华为技术有限公司 | Data reading and writing device and data reading and writing method |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0428017A (en) * | 1990-05-23 | 1992-01-30 | Nec Corp | Optical disk device |
| JPH0469819A (en) * | 1990-07-09 | 1992-03-05 | Nec Corp | Optical disk device |
| JPH04324123A (en) * | 1991-04-24 | 1992-11-13 | Koufu Nippon Denki Kk | Optical disk reading circuit |
-
1993
- 1993-12-27 JP JP33070793A patent/JPH07192343A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0428017A (en) * | 1990-05-23 | 1992-01-30 | Nec Corp | Optical disk device |
| JPH0469819A (en) * | 1990-07-09 | 1992-03-05 | Nec Corp | Optical disk device |
| JPH04324123A (en) * | 1991-04-24 | 1992-11-13 | Koufu Nippon Denki Kk | Optical disk reading circuit |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2004053862A1 (en) * | 2002-12-12 | 2004-06-24 | Pioneer Corporation | Information recording/reading head and information recording/reproducing device |
| US8630157B2 (en) | 2010-08-30 | 2014-01-14 | Kabushiki Kaisha Toshiba | Data reproducing apparatus |
| CN113744766A (en) * | 2020-05-29 | 2021-12-03 | 华为技术有限公司 | Data reading and writing device and data reading and writing method |
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