JPS5979446A - Magneto-optical head - Google Patents
Magneto-optical headInfo
- Publication number
- JPS5979446A JPS5979446A JP57190337A JP19033782A JPS5979446A JP S5979446 A JPS5979446 A JP S5979446A JP 57190337 A JP57190337 A JP 57190337A JP 19033782 A JP19033782 A JP 19033782A JP S5979446 A JPS5979446 A JP S5979446A
- Authority
- JP
- Japan
- Prior art keywords
- polarizer
- magneto
- light
- composite
- differential
- 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
Classifications
-
- 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
Landscapes
- Optical Head (AREA)
Abstract
Description
【発明の詳細な説明】
く技術分野〉
本発明は磁性膜を記録媒体とし、レーザ光等の光ビーム
を照射して情報の記録、再生、消去を行なう光磁気記憶
装置の磁気光学ヘッドに関する。DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a magneto-optic head for a magneto-optical storage device that uses a magnetic film as a recording medium and records, reproduces and erases information by irradiating it with a light beam such as a laser beam.
〈従来技術〉
近年、書き換えの出来る光メモリ装置として膜面に垂直
な方向に磁化容易軸をもつ磁性膜を記録媒体に利用した
光磁気記憶装置が活発に研究されている。しかしながら
、上記記録媒体の多くは再生信号の品質が十分でなく、
従ってこれを改善するための記録媒体材料の研究開発が
行なわれている。又その一方で再生光から良質の再生信
号を得る為の再生手法に関しても精力的に検討がなされ
ている。<Prior Art> In recent years, as a rewritable optical memory device, a magneto-optical storage device using a magnetic film having an axis of easy magnetization in a direction perpendicular to the film surface as a recording medium has been actively researched. However, many of the above-mentioned recording media do not have sufficient quality of reproduction signals,
Therefore, research and development of recording medium materials is being conducted to improve this problem. On the other hand, active studies are also being conducted on reproduction methods for obtaining high-quality reproduction signals from reproduction light.
光磁気記憶装置の再生は磁気によるレーザ光の偏光の回
転（カー効果、ファラデー効果）の現象を利用して行な
われるものであるが、一般的に上記偏光の回転角は小さ
く、更に再生光の光量が微弱であるという問題がある。Reproduction of magneto-optical storage devices is performed using the phenomenon of rotation of the polarization of laser light due to magnetism (Kerr effect, Faraday effect), but the rotation angle of the polarization is generally small, and furthermore, the rotation angle of the polarization is small, and the reproduction light There is a problem that the amount of light is weak.
又、上記再生光が微弱であるが為に記憶媒体表面に点在
するキズ、ゴミ等を原因とする反射光量あるいは透過光
量の変動、あるいは光源そのものの強度変動が再生信号
に与える影響は大きいものである。その為システムを構
成した場合Ｓ／Ｎ （信号対雑音比）は充分な値が得ら
れなかった。Furthermore, since the reproduction light mentioned above is weak, fluctuations in the amount of reflected light or transmitted light due to scratches, dust, etc. scattered on the surface of the storage medium, or fluctuations in the intensity of the light source itself, have a large effect on the reproduction signal. It is. Therefore, when the system was configured, a sufficient S/N (signal-to-noise ratio) value could not be obtained.
又以上の様な再生光の不要な強度変動を原因とする再生
信号Ｓ４の劣化を防止する手法として差動再生法がある
。第１図に従来より行なわれてきた差動再生法を適用し
た磁気光学ヘッドの基本構成図を示す。同図において記
憶媒体１から反射あるいは透過された光はハーフミラ−
２で２方向に分離され、分離後の光は検光子３，４にて
検波され、その後光検出器５，６によって検出される。Further, there is a differential regeneration method as a method for preventing deterioration of the reproduced signal S4 caused by unnecessary intensity fluctuations of the reproduced light as described above. FIG. 1 shows a basic configuration diagram of a magneto-optical head to which a conventional differential reproduction method is applied. In the figure, the light reflected or transmitted from the storage medium 1 is a half mirror.
The separated light is detected by analyzers 3 and 4, and then by photodetectors 5 and 6.
上記検光子３，４の透過軸は光検出器５．６によって光
電変換された信号の位相が１８０°すれる様な方位に夫
々設定される。従って上記光検出器５゜６において得ら
れた信号が差動増巾器７に入力され減算された結果、偏
光方位の変化に関与しない信号の変動（キズ、ゴミ等に
よる反則率の変動あるいはレーザ光源そのものの強度変
動）は相殺され、結果的に信号の品質が向上するもので
ある。The transmission axes of the analyzers 3 and 4 are set in such directions that the phases of the signals photoelectrically converted by the photodetectors 5.6 are shifted by 180 degrees. Therefore, the signal obtained by the photodetector 5.6 is input to the differential amplifier 7 and subtracted. As a result, signal fluctuations that are not related to changes in polarization direction (failure rate fluctuations due to scratches, dust, etc., or laser (intensity fluctuations of the light source itself) are canceled out, resulting in improved signal quality.
しかしながら上述の差動再生法を適用した磁気光学ヘッ
ドに用いられるハーフミラ−２において再生光を偏光状
態を保ったままで光エネルギーのみを４％することは非
常に困難である。これは、互いに直交する方向に偏波面
をもつ光に対する透過率と反射率とが夫々１：１であり
、しかも通過後の再偏光の位相ずれがない様な偏光特性
をもつハーフミラ−を得ることが非常に困難であること
による。この為に従来の差動再生法を用いる場合は位相
力月８０°ずれた各々の信号（光電変換後の信号）の信
号量の違いを増中器の増「１」度を調整することにより
差動効果を改善させていた。しかしこの手順は甚だ面倒
である。又上記従来の差動再生法を用いた磁気光学ヘッ
ドは光学系が複雑になるという問題も有していた。However, it is very difficult to reduce the optical energy by 4% while maintaining the polarization state of the reproducing light in the half mirror 2 used in the magneto-optical head to which the above-described differential reproducing method is applied. This is to obtain a half mirror that has polarization characteristics such that the transmittance and reflectance for light with polarization planes in directions perpendicular to each other are 1:1, and there is no phase shift of re-polarized light after passing through it. This is because it is extremely difficult. For this reason, when using the conventional differential regeneration method, the difference in signal amount of each signal (signal after photoelectric conversion) whose phase power is shifted by 80 degrees is adjusted by adjusting the intensification degree of the intensifier. The differential effect was improved. However, this procedure is extremely troublesome. Furthermore, the magneto-optical head using the conventional differential reproduction method described above also has a problem in that the optical system becomes complicated.
〈目的〉
本発明は以上の従来問題点を解消するべくなされたもの
であり、磁気光学ヘッドにおいて差動光学系を簡略化し
、且つ差動効果をも改善することを目的とするものであ
る。<Purpose> The present invention has been made to solve the above-mentioned conventional problems, and aims to simplify the differential optical system in a magneto-optical head and also improve the differential effect.
〈実施例〉
第２図は本発明に係る磁気光学ヘッドの一実施例の基本
構成説明図を示す。膜面に垂直な方向に磁化容易軸を有
する記憶媒体１に照射された後反η・１あるいは透過し
たレーザ光は複合偏光子８に入射する。この複合偏光子
８は例えばポーラロイド社製のＨ膜等の薄膜型偏光子を
２個その透過軸がその接合線に対して対称となるように
接合したものである。第２図の複合偏光子８に設けられ
た斜線は偏光子の方位を示している。又その接合線の方
向は再生光ビームが記憶媒体１上を相対移動する方向に
一致するように（若しくは磁気光学情報を含まない再生
光つまり基板の表面にて反射した光等の偏光方位に一致
する方向に）設定される。<Embodiment> FIG. 2 shows an explanatory diagram of the basic configuration of an embodiment of the magneto-optical head according to the present invention. The laser beam that has been irradiated onto the storage medium 1 having an axis of easy magnetization in the direction perpendicular to the film surface and that has been transmitted or transmitted is incident on the composite polarizer 8 . This composite polarizer 8 is made by bonding two thin film polarizers such as H film manufactured by Polaroid Co., Ltd. so that their transmission axes are symmetrical with respect to the bonding line. The diagonal lines provided on the composite polarizer 8 in FIG. 2 indicate the orientation of the polarizer. The direction of the joining line is set so that it coincides with the direction in which the reproduction light beam moves relative to the storage medium 1 (or coincides with the polarization direction of the reproduction light that does not contain magneto-optical information, that is, the light reflected from the surface of the substrate, etc.). direction).
又上記複合偏光子８の各々の偏光子の方位角は再生信号
の殊が最良となる様に調整されて接合される。通常上記
偏光子の方位角０は接合線に対して０°〈θ〈４５°に
設定される。上記複合偏光子８の夫々の偏光子を通過し
た検波光は上記複合偏光子８の接合線の方向と同一方向
に分割された２個の受光素子から構成される複合受光素
子９に入射する。この複合受光素子９にて光電変換され
た各々の情報信号は差動増巾器１０に入力され差動助成
１こ４って不要な信号光による影響を抑制するミ゛・ｉ
ブ
ことができる。Further, the azimuth angle of each polarizer in the composite polarizer 8 is adjusted and joined so that the reproduced signal becomes particularly optimal. Usually, the azimuth angle 0 of the polarizer is set at 0°<θ<45° with respect to the joining line. The detected light that has passed through each of the polarizers of the composite polarizer 8 enters a composite light receiving element 9 which is composed of two light receiving elements divided in the same direction as the joining line of the composite polarizer 8. Each information signal photoelectrically converted by the composite light receiving element 9 is input to a differential amplifier 10, and differential amplifier 1 to 4 suppresses the influence of unnecessary signal light.
You can do it.
〈効果〉
本発明によれば従来のようにノ＼−フミラーで再生光を
２分する手法よりも更に正確に再生光を２分できるので
十分な差動効果を得ることができる。<Effects> According to the present invention, the reproduced light can be divided into two parts more accurately than the conventional method of dividing the reproduced light into two parts using a nof mirror, so that a sufficient differential effect can be obtained.
又光学系の簡略化も可能となるものである。Furthermore, it is possible to simplify the optical system.
第１図は従来の磁気光学ヘッドの基本構成図、第２図は
本発明に係る磁気光学ヘッドの一実施例の基本構成説明
図を示す。
図中、１：記憶媒体、２：ハーフミラ−，３゜４：検光
子、５，６：光検出器、７二差動増巾器、８：複合偏光
子、９：複合受光素子、１０：差動増巾器。FIG. 1 is a diagram showing the basic configuration of a conventional magneto-optical head, and FIG. 2 is a diagram illustrating the basic configuration of an embodiment of the magneto-optic head according to the present invention. In the figure, 1: storage medium, 2: half mirror, 3° 4: analyzer, 5, 6: photodetector, 7 two-differential amplifier, 8: composite polarizer, 9: composite light receiving element, 10: Differential amplifier.
Claims (1)
る境界を有する２個の検光子を接合した複合検波素子を
配置し、前記２個の検光子により検波された夫々の光束
を受光する２個の光電変換素子を配置し、この２個の光
電変換素子の出力を差動増巾する構成としたことを特徴
とする磁気光学ヘッド。 ２、前記２個の検光子の透過軸の方位をその接合線に対
して対称としたことを特徴とする特許請求の範囲第１項
記載の磁気光学ヘッド。[Claims] 1. A composite detection element in which two analyzers are joined, which has a boundary that divides the reproduced light beam into two, is arranged in the optical path of the reproduced light beam, and the wave detected by the two analyzers is A magneto-optical head characterized in that two photoelectric conversion elements are arranged to receive respective light beams, and the outputs of the two photoelectric conversion elements are differentially amplified. 2. The magneto-optical head according to claim 1, wherein the orientations of the transmission axes of the two analyzers are symmetrical with respect to their joining line.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57190337A JPS5979446A (en) | 1982-10-28 | 1982-10-28 | Magneto-optical head |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57190337A JPS5979446A (en) | 1982-10-28 | 1982-10-28 | Magneto-optical head |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5979446A true JPS5979446A (en) | 1984-05-08 |
| JPH0363139B2 JPH0363139B2 (en) | 1991-09-30 |
Family
ID=16256510
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57190337A Granted JPS5979446A (en) | 1982-10-28 | 1982-10-28 | Magneto-optical head |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5979446A (en) |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6278742A (en) * | 1985-10-02 | 1987-04-11 | Seiko Instr & Electronics Ltd | Optical information detector |
| FR2597643A1 (en) * | 1985-11-08 | 1987-10-23 | Seiko Epson Corp | MAGNETO-OPTICAL SIGNAL READING SYSTEM |
| JPS63100639A (en) * | 1986-06-02 | 1988-05-02 | Seiko Epson Corp | Magneto-optical signal detecting method |
| EP0285126A2 (en) * | 1987-04-01 | 1988-10-05 | Nec Corporation | A head for a magnetooptic recording medium |
| JPH01166350A (en) * | 1987-09-30 | 1989-06-30 | Deutsche Thomson Brandt Gmbh | Optical scanner |
| EP0420694A2 (en) * | 1989-09-29 | 1991-04-03 | International Business Machines Corporation | Magneto-optical storage system |
| US5161133A (en) * | 1989-09-29 | 1992-11-03 | International Business Machines Corporation | Magneto-optical storage system |
| WO1993016469A1 (en) * | 1992-02-07 | 1993-08-19 | Sony Corporation | Phase varying device, and optical pickup apparatus using the same for magneto-optical storage |
| US5663940A (en) * | 1993-11-19 | 1997-09-02 | Sony Corporation | Optical pickup apparatus including hologram element |
| US5896360A (en) * | 1994-11-10 | 1999-04-20 | Sony Corporation | Optical pickup device and optical disc driving apparatus having light polarizing hologram |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5788540A (en) * | 1980-11-21 | 1982-06-02 | Olympus Optical Co Ltd | Method and apparatus for information read-in of optical magnetic recording medium |
-
1982
- 1982-10-28 JP JP57190337A patent/JPS5979446A/en active Granted
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5788540A (en) * | 1980-11-21 | 1982-06-02 | Olympus Optical Co Ltd | Method and apparatus for information read-in of optical magnetic recording medium |
Cited By (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6278742A (en) * | 1985-10-02 | 1987-04-11 | Seiko Instr & Electronics Ltd | Optical information detector |
| FR2597643A1 (en) * | 1985-11-08 | 1987-10-23 | Seiko Epson Corp | MAGNETO-OPTICAL SIGNAL READING SYSTEM |
| US4779250A (en) * | 1985-11-08 | 1988-10-18 | Seiko Epson Kabushiki Kaisha | Magneto-optical signal read-out system using divided photodetector |
| JPS63100639A (en) * | 1986-06-02 | 1988-05-02 | Seiko Epson Corp | Magneto-optical signal detecting method |
| EP0285126A2 (en) * | 1987-04-01 | 1988-10-05 | Nec Corporation | A head for a magnetooptic recording medium |
| JPH01166350A (en) * | 1987-09-30 | 1989-06-30 | Deutsche Thomson Brandt Gmbh | Optical scanner |
| EP0420694A2 (en) * | 1989-09-29 | 1991-04-03 | International Business Machines Corporation | Magneto-optical storage system |
| US5161133A (en) * | 1989-09-29 | 1992-11-03 | International Business Machines Corporation | Magneto-optical storage system |
| WO1993016469A1 (en) * | 1992-02-07 | 1993-08-19 | Sony Corporation | Phase varying device, and optical pickup apparatus using the same for magneto-optical storage |
| US5563869A (en) * | 1992-02-07 | 1996-10-08 | Sony Corporation | Prism has a plurality of reflective regions each with a predetermined phase difference |
| US5577018A (en) * | 1992-02-07 | 1996-11-19 | Sony Corporation | Phase changing apparatus and optical pickup apparatus for magneto-optic storage device using same |
| US5742577A (en) * | 1992-02-07 | 1998-04-21 | Sony Corporation | Prism has a plurality of reflective regions each with a predetermined phase difference |
| US5717667A (en) * | 1993-11-11 | 1998-02-10 | Sony Corporation | Optical pickup apparatus including an optical rotation device |
| US5663940A (en) * | 1993-11-19 | 1997-09-02 | Sony Corporation | Optical pickup apparatus including hologram element |
| US5896360A (en) * | 1994-11-10 | 1999-04-20 | Sony Corporation | Optical pickup device and optical disc driving apparatus having light polarizing hologram |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0363139B2 (en) | 1991-09-30 |
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