JPS63239639A - Magneto-optical reproducing device - Google Patents
Magneto-optical reproducing deviceInfo
- Publication number
- JPS63239639A JPS63239639A JP7327387A JP7327387A JPS63239639A JP S63239639 A JPS63239639 A JP S63239639A JP 7327387 A JP7327387 A JP 7327387A JP 7327387 A JP7327387 A JP 7327387A JP S63239639 A JPS63239639 A JP S63239639A
- Authority
- JP
- Japan
- Prior art keywords
- detecting
- signal
- magneto
- output
- amplitude
- 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.)
- Granted
Links
- 230000007547 defect Effects 0.000 claims abstract description 21
- 238000001514 detection method Methods 0.000 claims description 19
- 230000003287 optical effect Effects 0.000 claims description 4
- 230000002950 deficient Effects 0.000 abstract description 14
- 238000010586 diagram Methods 0.000 description 8
- 230000000694 effects Effects 0.000 description 6
- 230000005374 Kerr effect Effects 0.000 description 4
- 238000000034 method Methods 0.000 description 2
- 230000010287 polarization Effects 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- 230000008033 biological extinction Effects 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 230000005415 magnetization Effects 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B19/00—Driving, starting, stopping record carriers not specifically of filamentary or web form, or of supports therefor; Control thereof; Control of operating function ; Driving both disc and head
- G11B19/02—Control of operating function, e.g. switching from recording to reproducing
- G11B19/04—Arrangements for preventing, inhibiting, or warning against double recording on the same blank or against other recording or reproducing malfunctions
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B11/00—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor
- G11B11/10—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field
- G11B11/105—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field using a beam of light or a magnetic field for recording by change of magnetisation and a beam of light for reproducing, i.e. magneto-optical, e.g. light-induced thermomagnetic recording, spin magnetisation recording, Kerr or Faraday effect reproducing
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B11/00—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor
- G11B11/10—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field
- G11B11/105—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field using a beam of light or a magnetic field for recording by change of magnetisation and a beam of light for reproducing, i.e. magneto-optical, e.g. light-induced thermomagnetic recording, spin magnetisation recording, Kerr or Faraday effect reproducing
- G11B11/10502—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field using a beam of light or a magnetic field for recording by change of magnetisation and a beam of light for reproducing, i.e. magneto-optical, e.g. light-induced thermomagnetic recording, spin magnetisation recording, Kerr or Faraday effect reproducing characterised by the transducing operation to be executed
- G11B11/10515—Reproducing
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B11/00—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor
- G11B11/10—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field
- G11B11/105—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field using a beam of light or a magnetic field for recording by change of magnetisation and a beam of light for reproducing, i.e. magneto-optical, e.g. light-induced thermomagnetic recording, spin magnetisation recording, Kerr or Faraday effect reproducing
- G11B11/10532—Heads
- G11B11/10541—Heads for reproducing
- G11B11/10543—Heads for reproducing using optical beam of radiation
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B11/00—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor
- G11B11/10—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field
- G11B11/105—Recording on or reproducing from the same record carrier wherein for these two operations the methods are covered by different main groups of groups G11B3/00 - G11B7/00 or by different subgroups of group G11B9/00; Record carriers therefor using recording by magnetic means or other means for magnetisation or demagnetisation of a record carrier, e.g. light induced spin magnetisation; Demagnetisation by thermal or stress means in the presence or not of an orienting magnetic field using a beam of light or a magnetic field for recording by change of magnetisation and a beam of light for reproducing, i.e. magneto-optical, e.g. light-induced thermomagnetic recording, spin magnetisation recording, Kerr or Faraday effect reproducing
- G11B11/10595—Control of operating function
- G11B11/10597—Adaptations for transducing various formats on the same or different carriers
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B7/00—Recording or reproducing by optical means, e.g. recording using a thermal beam of optical radiation by modifying optical properties or the physical structure, reproducing using an optical beam at lower power by sensing optical properties; Record carriers therefor
- G11B7/08—Disposition or mounting of heads or light sources relatively to record carriers
- G11B7/09—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following
- G11B7/0948—Disposition or mounting of heads or light sources relatively to record carriers with provision for moving the light beam or focus plane for the purpose of maintaining alignment of the light beam relative to the record carrier during transducing operation, e.g. to compensate for surface irregularities of the latter or for track following specially adapted for detection and avoidance or compensation of imperfections on the carrier, e.g. dust, scratches, dropouts
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、レーザ発振器と、レーザ発振器から発射され
、光磁気記録媒体面上に照射された光束の反射光あるい
は透過光の光路中に配設された光分割手段と、光分割手
段によって分割された両光束の情報信号をそれぞれ検出
する第１．第２の光検出器と、第１都よび第２の光検出
器からの情報信号の差信号を検出する差動増幅器とを有
する光磁気再生装置に関する。[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a laser oscillator and a laser beam disposed in the optical path of reflected light or transmitted light of a luminous flux emitted from the laser oscillator and irradiated onto the surface of a magneto-optical recording medium. a first beam splitting means provided therein, and a first beam splitting means for detecting the information signals of both the beams split by the light splitting means. The present invention relates to a magneto-optical reproducing device having a second photodetector and a differential amplifier that detects a difference signal between information signals from the first and second photodetectors.
従来、この種の光磁気再生装置は、情報信号の記録され
た光磁気記録媒体から磁気記録情報を再生するのにカー
効果、ファラデー効果と呼ばれる磁気光学効果を利用し
ている。Conventionally, this type of magneto-optical reproducing apparatus utilizes magneto-optic effects called the Kerr effect and the Faraday effect to reproduce magnetically recorded information from a magneto-optical recording medium on which information signals are recorded.
第４図はカー効果を利用した従来の光磁気記録再生装置
を示す構成図である。この光磁気記録再生装置では、半
導体レーザ１より発射されるレーザ光はコリメータレン
ズ２により平行光に直され、偏光子３、ビームスプリッ
タ４を通り、対物レンズ５によって微小な光スポットに
絞られて、光磁気記録媒体６の表面に照射されて反射さ
れる。このとき、照射される光磁気記録媒体の磁化状態
によって反射光の偏光状態が変化する。反射光は再び対
物レンズ５を通りビームスプリッタ４によって光路を曲
げられて％波長板７を通り、反射光の偏光面を回転させ
て、検光子８に送られ、反射光の偏光面に応じてレンズ
１０．またはレンズ１０２へ導かれそれぞれ光検出器１
１． 、１１２に集光されて、対応する信号が出力され
る。検出器】ＩＩ。FIG. 4 is a block diagram showing a conventional magneto-optical recording/reproducing device using the Kerr effect. In this magneto-optical recording and reproducing device, a laser beam emitted from a semiconductor laser 1 is converted into parallel light by a collimator lens 2, passes through a polarizer 3 and a beam splitter 4, and is focused into a minute light spot by an objective lens 5. , is irradiated onto the surface of the magneto-optical recording medium 6 and is reflected. At this time, the polarization state of the reflected light changes depending on the magnetization state of the irradiated magneto-optical recording medium. The reflected light passes through the objective lens 5 again, its optical path is bent by the beam splitter 4, passes through the % wave plate 7, rotates the polarization plane of the reflected light, and sends it to the analyzer 8. Lens 10. or guided to the lens 102 and the photodetector 1, respectively.
1. , 112, and a corresponding signal is output. Detector】II.
１１２の出力はそれぞれ差動増幅器１２の非反転１反転
入力端に入力され、差動増幅器１２で増幅されＲＦ検出
信号２７として出力される。The outputs of 112 are respectively input to the non-inverting and 1-inverting input terminals of the differential amplifier 12, amplified by the differential amplifier 12, and output as the RF detection signal 27.
第５図は磁気カー効果を利用した光磁気記録の再生原理
を説明するための図である。Ｐｉは光磁気記録媒体６に
入射する偏光を、Ｒ′″は例えば媒体膜面下方に磁化さ
れた領域から反射される偏光を、Ｒ−は媒体■ｑ面上方
に磁化された領域から反射される偏光をそれぞれ表して
いる。また、θにはカー回転角と呼ばれるもので磁気光
学効果によって光の振動面が回転する量を表わしている
。FIG. 5 is a diagram for explaining the reproduction principle of magneto-optical recording using the magnetic Kerr effect. Pi represents the polarized light incident on the magneto-optical recording medium 6, R'' represents the polarized light reflected from the magnetized region below the medium film surface, and R- represents the polarized light reflected from the magnetized region above the medium q surface. In addition, θ is called the Kerr rotation angle and represents the amount by which the vibration plane of light is rotated by the magneto-optic effect.
このとき、光磁気記録媒体６の交互に磁化された領域を
再生光スポットが走査するときに、弼波長板７を消光位
置から設定角θだけ機械的に回転させると、その透過光
は記録媒体から反射される光量をＰとして、次式（１）
で表される強度差Ｓをもった変調光となり、光検出器１
１． 、１１２によって光再生される。At this time, when the reproducing light spot scans the alternately magnetized areas of the magneto-optical recording medium 6, when the narrow wavelength plate 7 is mechanically rotated by a set angle θ from the extinction position, the transmitted light is transmitted to the recording medium. The amount of light reflected from P is the following formula (1)
The light becomes modulated with an intensity difference S expressed by the photodetector 1.
1. , 112 for optical reproduction.
５＝Ｐｓｉｎ２θｋｓｉｎ２θ −−−−−（１）こ
の場合、再生信号の信号対雑音比（ＳＮ比）を最大にす
るように％波長板７を機械的に回転させて設定角θを最
適な設定角θ。に設定する必要がある。この％波長板７
の設定角θには、光検出器１１． 、 ＩＩ２に係るノ
イズと記録媒体６からの反射光の変動によるノイズが大
きく影ツしてくる。5=Psin2θksin2θ -------(1) In this case, the setting angle θ is set to the optimum setting angle by mechanically rotating the % wave plate 7 so as to maximize the signal-to-noise ratio (SN ratio) of the reproduced signal. θ. It is necessary to set it to . This% wavelength plate 7
At the set angle θ, the photodetector 11. , II2 and noise due to fluctuations in the reflected light from the recording medium 6 are greatly affected.
そこで、反射光の変動による同相ノイズを除去する方法
として、第４図で示されるような差動検出法が広く用い
られている。 ゛
〔発明が解決しようとする問題点〕
上述した従来の光磁気記録再生装置は、光磁気記録媒体
の欠陥部分をＲＦ検出信号の振幅低下として検出してい
たので、欠陥部分の検出が不十分であり、特に映像信号
をＦＭ変調して記録再生するアナログ方式においては、
欠陥部分が視覚上の画質を落とすノイズとして表われる
という欠点がある。Therefore, a differential detection method as shown in FIG. 4 is widely used as a method for removing common-mode noise caused by fluctuations in reflected light. [Problems to be Solved by the Invention] The conventional magneto-optical recording/reproducing device described above detects the defective portion of the magneto-optical recording medium as a decrease in the amplitude of the RF detection signal, so the defective portion is insufficiently detected. In particular, in analog systems that record and reproduce video signals by FM modulating them,
The disadvantage is that the defective parts appear as noise that degrades the visual quality of the image.
本発明の光磁気再生装置は、
第１．第２の光検出器からの情報信号の和信号を検出す
る加算増幅器と、
加算増幅器の出力を人力し、その人力が予め設定された
第１の基準比較振幅値を超えたことを検出すると検出信
号を出力する第１の振幅検出器と、
差動増幅器の出力を入力し、その入力が予め設定された
第２の基準比較振幅値を超えたことを検出すると検出信
号を出力する第２の振幅検出器と５
第１．第２の振幅検出器の検出信号の論理和をとり、欠
陥検出信号を出力する論理和回路とを有する。The magneto-optical reproducing device of the present invention has the following features: 1. a summing amplifier that detects the sum signal of the information signals from the second photodetector; and a summing amplifier that manually inputs the output of the summing amplifier, and detects when the output of the summing amplifier exceeds a preset first reference comparison amplitude value. a first amplitude detector that outputs a signal; and a second amplitude detector that receives the output of the differential amplifier and outputs a detection signal when it detects that the input exceeds a preset second reference comparison amplitude value. Amplitude detector and 5 1st. and a logical sum circuit that calculates the logical sum of the detection signals of the second amplitude detector and outputs a defect detection signal.
本発明は、光磁気記録媒体の欠陥部分には、反射率の変
化を伴う欠陥と、カー回転の変化を伴う欠陥があること
に着目し、第１．第２の光検出器の出力の和信号、差信
号を作成し、予め設定した第１．第２の基準比較振幅値
と比較して、それぞれの欠陥を検出することにより、欠
陥部分の検出能力を大幅に向上させるようにしたもので
ある。The present invention focuses on the fact that defective portions of magneto-optical recording media include defects accompanied by changes in reflectance and defects accompanied by changes in Kerr rotation. A sum signal and a difference signal of the output of the second photodetector are created, and a preset first photodetector is generated. By comparing each defect with the second reference comparison amplitude value, the ability to detect defective portions is greatly improved.
次に、本発明の実施例について図面を参照して説明する
。Next, embodiments of the present invention will be described with reference to the drawings.
第１図は本発明の光磁気再生装置の一実施例を示す構成
図、第２図、第３図は第１図中の比較器１９、２４．３
０の入出力の関係を示す波形図である。FIG. 1 is a block diagram showing an embodiment of the magneto-optical reproducing apparatus of the present invention, and FIGS. 2 and 3 show comparators 19, 24.3 in FIG.
FIG. 3 is a waveform diagram showing the relationship between input and output of 0;
本実施例は、第４図で示された従来例の光検出器１１□
、１１□の出力を加算増幅する加算増幅器１８と、反転
入力端には電源電圧＋■を抵抗器２１と可変抵抗器２０
とで分圧した電圧が基準比較振幅値ｖｃ工として印加さ
れ、非反転入力端には加算増幅器１８の出力が印加され
ている比較器１９と、反転入力端には電源電圧＋Ｖを抵
抗器２２と可変抵抗器２３とで分圧した電圧が基準比較
振幅値ＶＣ２として印加され、非反転入力端には差動増
幅器１２のＲＦ検出信号２７が印加されている比較器２
４と、非反転入力端には電源電圧−Ｖを抵抗器２９と可
変抵抗器２８とで分圧した電圧が基準比較振幅値ＶＣ３
として印加され、反転入力端には差動増幅器１２のＲＦ
検出信号２７が印加されている比較器３０と、比較器１
８゜２４、３０の出力の論理和をとり欠陥検出信号２６
として出力するオア回路２５とが第４図の従来例に付加
されて構成されている。This embodiment uses the conventional photodetector 11□ shown in FIG.
, 11□, a summing amplifier 18 that adds and amplifies the outputs, and a resistor 21 and a variable resistor 20 to which the power supply voltage +
The voltage divided by the comparator 19 is applied as a reference comparison amplitude value vc, the output of the summing amplifier 18 is applied to the non-inverting input terminal, and the power supply voltage +V is applied to the resistor 22 to the inverting input terminal. The voltage divided by the variable resistor 23 is applied as the reference comparison amplitude value VC2, and the RF detection signal 27 of the differential amplifier 12 is applied to the non-inverting input terminal of the comparator 2.
4, and the voltage obtained by dividing the power supply voltage -V by the resistor 29 and the variable resistor 28 is the reference comparison amplitude value VC3 at the non-inverting input terminal.
RF of the differential amplifier 12 is applied to the inverting input terminal.
A comparator 30 to which the detection signal 27 is applied, and a comparator 1
8. Take the logical sum of the outputs of 24 and 30 and generate the defect detection signal 26.
An OR circuit 25 which outputs 1 is added to the conventional example shown in FIG.
次に本実施例の動作について説明する。Next, the operation of this embodiment will be explained.
光検出器１１１ 、１１２で検出される信号成分は逆位
相のため、通常では加算増幅器１８の出力端には出力が
ほとんど現われない。しかし反射率変化をともなう欠陥
部分があったときには、光検出器１１、 、１１２で検
出される信号は同位相のため、加算増幅器１８で増幅さ
れ、出力端に出力が現われる。この出力が基準比較振幅
値ＶＣＩを超えると比較器１θの出力が現われる（第２
図）、光検出器１１、および１１２で検出された信号成
分は逆位相のため、差動増幅器１２にて増幅されＲＦ検
出信号２７として出力されている０位相変化を伴う欠陥
部分があったときは、再生光は信号光と同様成分のため
差動増幅器１２にて増幅され、出力に現われる。Since the signal components detected by the photodetectors 111 and 112 have opposite phases, almost no output appears at the output terminal of the summing amplifier 18 normally. However, when there is a defective portion accompanied by a change in reflectance, the signals detected by the photodetectors 11, 112 are in phase, so they are amplified by the summing amplifier 18, and an output appears at the output terminal. When this output exceeds the reference comparison amplitude value VCI, the output of comparator 1θ appears (second
(Figure), the signal components detected by the photodetectors 11 and 112 have opposite phases, so when there is a defective part with a 0 phase change that is amplified by the differential amplifier 12 and output as the RF detection signal 27. Since the reproduced light has the same components as the signal light, it is amplified by the differential amplifier 12 and appears as an output.
この増幅された欠陥部分の信号が、比較器２４において
は基準比較振幅値ＶＣ２以上の時、また比較器３０にお
いては基準比較振幅値■ｃ３以下の時にそれぞれの出力
にハイレベルの信号が出力される（第３図）、オア回路
２５は比較器１９．２４．３０の出力の論理和をとり、
欠陥検出信号２８として出力する。When the amplified signal of the defective portion is equal to or higher than the reference comparison amplitude value VC2 in the comparator 24, and when it is equal to or less than the reference comparison amplitude value ■c3 in the comparator 30, a high-level signal is output to each output. (Fig. 3), the OR circuit 25 takes the logical sum of the outputs of the comparators 19, 24, and 30, and
It is output as a defect detection signal 28.
したがって、欠陥補正回路（不図示）はこの欠陥検出信
号２８に基づいて、再生映像信号の欠陥ノイズを補正で
きる。Therefore, a defect correction circuit (not shown) can correct defect noise in the reproduced video signal based on this defect detection signal 28.
以上説明したように本発明は、光磁気記録媒体の欠陥部
分には、反射率の変化を伴う欠陥と、カー回転の変化を
伴う欠陥があることに着目し、第１．第２の光検出器の
出力の和信号、差信号を作成し、予め設定した第１．第
２の基準比較振幅値と比較して、それぞれの欠陥を検出
することにより、欠陥部分の検出能力を大幅に向上マき
る効果があり、その結果、映像信号をＦＭ変調して記録
再生するアナログ方式の光磁気記録再生装置等において
は、欠陥検出信号で欠陥補正回路を制御することにより
、欠陥ノイズを十分に補正することが可能になり、画面
上に欠陥ノイズが目立たない高品位な記録再生画像を得
ることができる効果もある。As explained above, the present invention focuses on the fact that defective portions of magneto-optical recording media include defects accompanied by changes in reflectance and defects accompanied by changes in Kerr rotation. A sum signal and a difference signal of the output of the second photodetector are created, and a preset first photodetector is generated. By comparing each defect with the second standard comparison amplitude value, the ability to detect defective parts can be greatly improved.As a result, the analog In magneto-optical recording and reproducing devices using this method, by controlling the defect correction circuit with the defect detection signal, it is possible to sufficiently correct defect noise, allowing high-quality recording and reproducing with no noticeable defect noise on the screen. There is also the effect of being able to obtain images.
第１図は本発明の光磁気再生装置の一実施例を示す構成
図、第２図、第３図は比較器１９．２４．３０の入出力
の関係を示す波形図、第４図は従来例を示す構成図、第
５図は磁気カー効果を利用した光磁気記録の再生原理を
示す説明図である。
１・・・半導体レーザ、
２・・・コリメータレンズ、
３・・・偏光子、
４・・・ビームスプリッタ、
５・・・対物レンズ、
６・・・光磁気記録媒体、
７・・・弼波長板、
８・・・検光子、
１０、 、 ＋０２・・・レンズ、
ＩＩ、 、 １１２−・・光検出器、
＋ ２−・・差動増幅器、
１８−・・加算増幅器、
１９、２４．３０−・・比較器、
２０、２３．２８−・・可変抵抗器、
２１、２２．２９−・・抵抗器、
２５・・・オア回路、
２６・・・欠陥検出信号、
２７−ＲＦ検出信号。FIG. 1 is a block diagram showing an embodiment of the magneto-optical reproducing device of the present invention, FIGS. 2 and 3 are waveform diagrams showing the relationship between input and output of comparators 19, 24, and 30, and FIG. 4 is a conventional A configuration diagram showing an example, and FIG. 5 is an explanatory diagram showing the reproduction principle of magneto-optical recording using the magnetic Kerr effect. DESCRIPTION OF SYMBOLS 1... Semiconductor laser, 2... Collimator lens, 3... Polarizer, 4... Beam splitter, 5... Objective lens, 6... Magneto-optical recording medium, 7... Upper wavelength Plate, 8... Analyzer, 10, , +02... Lens, II, , 112-... Photodetector, + 2-... Differential amplifier, 18-... Summing amplifier, 19, 24.30 --Comparator, 20, 23.28--Variable resistor, 21, 22.29--Resistor, 25-OR circuit, 26-Defect detection signal, 27-RF detection signal.
Claims (1)
録媒体面上に照射された光束の反射光あるいは透過光の
光路中に配設された光分割手段と、光分割手段によって
分割された両光束の情報信号をそれぞれ検出する第１、
第２の光検出器と、第１および第２の光検出器からの情
報信号の差信号を検出する差動増幅器とを有する光磁気
再生装置において、 第１、第２の光検出器からの情報信号の和信号を検出す
る加算増幅器と、 加算増幅器の出力を入力し、その入力が予め設定された
第１の基準比較振幅値を超えたことを検出すると検出信
号を出力する第１の振幅検出器と、 差動増幅器の出力を入力し、その入力が予め設定された
第２の基準比較振幅値を超えたことを検出すると検出信
号を出力する第２の振幅検出器と、 第１、第２の振幅検出器の検出信号の論理和をとり、欠
陥検出信号を出力する論理和回路とを有することを特徴
とする光磁気再生装置。[Claims] A laser oscillator, a light splitting means disposed in the optical path of the reflected light or transmitted light of the light beam emitted from the laser oscillator and irradiated onto the surface of the magneto-optical recording medium, and the light splitting means a first one that detects the information signals of both the divided beams, respectively;
In a magneto-optical reproducing device having a second photodetector and a differential amplifier that detects a difference signal between information signals from the first and second photodetectors, a summing amplifier that detects a sum signal of information signals; and a first amplitude that receives the output of the summing amplifier and outputs a detection signal when it detects that the input exceeds a preset first reference comparison amplitude value. a second amplitude detector that receives the output of the differential amplifier and outputs a detection signal when it detects that the input exceeds a preset second reference comparison amplitude value; 1. A magneto-optical reproducing device comprising: an OR circuit that performs an OR operation on the detection signals of the second amplitude detector and outputs a defect detection signal.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7327387A JPH0654554B2 (en) | 1987-03-26 | 1987-03-26 | Magneto-optical reproducing device |
| US07/149,565 US4951154A (en) | 1987-01-28 | 1988-01-28 | Magneto-optic recording/reproducing apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7327387A JPH0654554B2 (en) | 1987-03-26 | 1987-03-26 | Magneto-optical reproducing device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63239639A true JPS63239639A (en) | 1988-10-05 |
| JPH0654554B2 JPH0654554B2 (en) | 1994-07-20 |
Family
ID=13513384
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7327387A Expired - Fee Related JPH0654554B2 (en) | 1987-01-28 | 1987-03-26 | Magneto-optical reproducing device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0654554B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0674311A2 (en) * | 1994-03-22 | 1995-09-27 | SANYO ELECTRIC Co., Ltd. | Circuit for discriminating pre-mastered pits and pre-mastered grooves on optical disk |
-
1987
- 1987-03-26 JP JP7327387A patent/JPH0654554B2/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0674311A2 (en) * | 1994-03-22 | 1995-09-27 | SANYO ELECTRIC Co., Ltd. | Circuit for discriminating pre-mastered pits and pre-mastered grooves on optical disk |
| EP0674311A3 (en) * | 1994-03-22 | 1996-01-03 | Sanyo Electric Co | Circuit for discriminating pre-mastered pits and pre-mastered grooves on optical disk. |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0654554B2 (en) | 1994-07-20 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |