JPH01211258A - Magneto-optical pickup device - Google Patents
Magneto-optical pickup deviceInfo
- Publication number
- JPH01211258A JPH01211258A JP63035561A JP3556188A JPH01211258A JP H01211258 A JPH01211258 A JP H01211258A JP 63035561 A JP63035561 A JP 63035561A JP 3556188 A JP3556188 A JP 3556188A JP H01211258 A JPH01211258 A JP H01211258A
- Authority
- JP
- Japan
- Prior art keywords
- magneto
- light
- phase compensation
- optical
- recording medium
- 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
- 230000003287 optical effect Effects 0.000 claims abstract description 28
- 238000001514 detection method Methods 0.000 claims description 4
- 238000000576 coating method Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000011521 glass Substances 0.000 description 3
- 239000011248 coating agent Substances 0.000 description 2
- 240000008866 Ziziphus nummularia Species 0.000 description 1
- 239000011449 brick Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 239000005357 flat glass Substances 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 230000001568 sexual effect Effects 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
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
Abstract
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は、光磁気ピックアップ装置、即ち光磁気ディス
ク用の光学ピックアップ装置に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magneto-optical pickup device, that is, an optical pickup device for a magneto-optical disk.
本発明は、光磁気ピックアップ装置において、レーザ源
から光磁気記録媒体への往きの光路に、光ビームの反射
ミラーと位相補償機能を兼ねた光学素子を配し、この光
学素子で光磁気記録媒体からの戻り光の位相補償を行う
ことによって、従来の光磁気ピックアップ装置の戻り光
路における位相補償板を省略し、光磁気ピックアップ装
置の省スペース化を図り且つ光磁気ピックアップ装置を
安価に提供できるようにしたものである。The present invention provides a magneto-optical pickup device in which an optical element serving as a light beam reflection mirror and a phase compensation function is disposed in the optical path from a laser source to a magneto-optical recording medium, and this optical element is used to drive the magneto-optical recording medium. By performing phase compensation of the return light from the magneto-optical pickup device, the phase compensation plate in the return optical path of the conventional magneto-optical pickup device can be omitted, and the space of the magneto-optical pickup device can be saved and the magneto-optical pickup device can be provided at low cost. This is what I did.
第４図は従来の光磁気ディスク用光学ピックアップ装置
の例を示す。同図において、（１）は光磁気記録媒体で
ある光磁気ディスク、（６）はレーザ光源を示す。レー
ザ光源（６）からの光ビームはコリメータレンズ（５）
で平行光に変換され、ビームスプリッタ（４）で９０°
方向に反射され、プリズムミラー（３）、対物レンズ（
２）を経て光磁気ディスク（１）上に集光される。必要
に応じて図示の如くプリズムミラー（３）を光路中に設
けることにより、光学ピックアップ装置自体を第４図に
図示するように光磁気ディスク（１）と平行な方向に配
設することができるので、光学ピックアップ装置自体の
薄型化を図ることができる。光磁気ディスク（１）を反
射した戻りの光ビームはプリズムミラー（３）で反射さ
れ、ビームスプリッタ（４）を透過した後、ビームスプ
リッタ（７）で２つの光ビームに分割される。一方の光
ビームは集光レンズ（８）を経てトラッキングサーボ、
フォーカスサーボ用のフォトダイオード（９）に達する
。他方の光ビームは光磁気ディスク（１）で生じた偏光
の楕円率（位相差）を補正する位相補償板（１０）、１
７２波長板（１１）を経て偏光ビームスプリッタ（１２
）とフォトダイオード（１４） （１６）により差動検
出されて再生信号が得られる。（１３）及び（１５）は
集光レンズである。FIG. 4 shows an example of a conventional optical pickup device for a magneto-optical disk. In the figure, (1) shows a magneto-optical disk which is a magneto-optical recording medium, and (6) shows a laser light source. The light beam from the laser light source (6) passes through the collimator lens (5)
is converted into parallel light by the beam splitter (4), and the beam splitter (4)
It is reflected in the direction of the prism mirror (3) and the objective lens (
2) and is focused onto the magneto-optical disk (1). If necessary, by providing a prism mirror (3) as shown in the optical path, the optical pickup device itself can be arranged in a direction parallel to the magneto-optical disk (1) as shown in FIG. Therefore, the optical pickup device itself can be made thinner. The returning light beam reflected from the magneto-optical disk (1) is reflected by a prism mirror (3), passes through a beam splitter (4), and is then split into two light beams by a beam splitter (7). One of the light beams passes through a condensing lens (8) and then passes through a tracking servo.
It reaches the photodiode (9) for focus servo. The other light beam is transmitted through a phase compensation plate (10), which corrects the ellipticity (phase difference) of polarized light generated by the magneto-optical disk (1).
72 wavelength plate (11) and a polarizing beam splitter (12).
) and photodiodes (14) and (16) perform differential detection to obtain a reproduced signal. (13) and (15) are condenser lenses.
上述した様に従来の光磁気ピックアップ装置（１７）は
、Ｃ／Ｎ向上のために戻り光路に偏光の楕円率補正用の
位相補償板（ｌＯ）が配置される。しかるに、かかる装
置（１７）においては位相補償板（１０）が水晶で構成
されてふり高価であること、位相補償板（１０）の位置
決め精度が厳しいこと、位相補償板（１０）がスペース
（場所）をとること等の欠点を有していた。As described above, in the conventional magneto-optical pickup device (17), a phase compensation plate (10) for correcting the ellipticity of polarized light is arranged in the return optical path in order to improve the C/N. However, in such a device (17), the phase compensation plate (10) is made of quartz crystal and is expensive, the positioning accuracy of the phase compensation plate (10) is strict, and the phase compensation plate (10) requires space (location). ).
本発明は、かかる問題点を解消した光磁気ピックアップ
装置を提供するものである。The present invention provides a magneto-optical pickup device that solves these problems.
本発明の光磁気ピックアップ装置は、レーザ光源（６）
と、このレーザ光源（６）からの光ビームを全反射して
所定方向に曲げて光磁気記録媒体上に光ビームを集束さ
せる対物レンズに導くと共に、対物レンズを介した光磁
気記録媒体（１）からの戻り光の位相補償を行う光学素
子（１８） （又は（２２） ）と、この光学素子（
１８）を介して光磁気記録媒体（１）からの戻り光を受
光する検出手段 （１４） （１６）とを具備して成る
ものである。The magneto-optical pickup device of the present invention includes a laser light source (6)
The light beam from the laser light source (6) is totally reflected, bent in a predetermined direction, and guided to an objective lens that focuses the light beam onto the magneto-optical recording medium. ), an optical element (18) (or (22) ) that performs phase compensation of the return light from
Detecting means (14) and (16) for receiving return light from the magneto-optical recording medium (1) via a magneto-optical recording medium (18).
光学素子（１８） （又は（２２） ）としては、例え
ばプリズム型又は傾斜させた平行平板の光透過性部材よ
り成り、光ビームを光透過性部材に入射させた後、傾斜
した裏面即ち光透過性部材と空気との界面の反射面で全
反射させて透過させるように構成したものを用い得る。The optical element (18) (or (22)) is made of, for example, a prism-type or inclined parallel flat plate light-transmitting member, and after a light beam is made incident on the light-transmitting member, the inclined back surface, that is, the light-transmitting member, is used. It is possible to use a configuration configured to completely reflect the light on a reflective surface at the interface between the sexual member and the air and transmit the light.
レーザ光源からの光ビームは直線偏光で光学素子（１８
） （又は（２２））内に入り、裏面の反射面（２１）
〈又は（２３） ）で全反射された後、光磁気記録媒体
（１）に集光される。直線偏光された光ビームは光学素
子（１８） （又は（２２））での反射面（２１＞ （
又は（２３））を通過しても位相が変わらないでそのま
ま直線偏光で光磁気記録媒体（１）に達する。The light beam from the laser light source is linearly polarized and passes through an optical element (18
) (or (22)) and the reflective surface on the back (21)
After being totally reflected by (or (23)), the light is focused on the magneto-optical recording medium (1). The linearly polarized light beam is reflected by the reflection surface (21> (
or (23)), the phase remains unchanged and the light reaches the magneto-optical recording medium (1) as linearly polarized light.
次に、光磁気記録媒体（１）を反射した戻りの光ビーム
は、光磁気記録媒体（１）によりＰ偏光成分とＳ偏光成
分との位相差δ５−ｐ（＝δＳ−δＰ、δＰ：Ｐ偏光成
分の位相変化、δｓｒｓ偏光成分の位相変化）を生じ楕
円偏光となる。この戻りの光ビームが光学素子（１８）
（又は（２２） ）内を通り反射面（２１） （又は
（２３））で全反射する際に光磁気記録媒体（１）で生
じた位相差δ、−１が打消され、直線偏光に変換されて
検出手段（１４） （１６）に達する。Next, the returning light beam reflected from the magneto-optical recording medium (1) is processed by the magneto-optical recording medium (1), with a phase difference δ5-p (=δS-δP, δP:P) between the P-polarized component and the S-polarized component. This causes a phase change in the polarized light component and a phase change in the δsrs polarized light component, resulting in elliptically polarized light. This returning light beam passes through the optical element (18)
(or (22)) and is totally reflected by the reflecting surface (21) (or (23)), the phase difference δ, -1 generated in the magneto-optical recording medium (1) is canceled and converted into linearly polarized light. and reaches the detection means (14) (16).
即ち、光学素子（１８） （又は（２２） ）で生ずる
Ｐ偏光とＳ偏光の位相差δｐ−ｓ（”δＰ−δＳ）を計
算すると次式が求まる。この位相差δ、−３は光磁気記
録媒体（１）で生じた位相差δ８−１と符号が逆である
。That is, by calculating the phase difference δp-s ("δP-δS) between the P-polarized light and the S-polarized light generated in the optical element (18) (or (22)), the following equation is obtained. This phase difference δ, -3 is due to magneto-optical The sign is opposite to the phase difference δ8-1 generated in the recording medium (1).
但し、θｉは入射角
ｎ＝ （Ｎは光学素子の屈折率）戻り光の光学素
子（１８） （又は（２２） ）への入射角θ１ と光
学素子の屈折率Ｎを選ぶことによって光磁気記録媒体（
１）で生じた位相差δ、−１を打消ことができる。従っ
て、従来の戻り光路に配した位相補償板（１０）は省略
される。However, θi is the incident angle n= (N is the refractive index of the optical element). By selecting the incident angle θ1 of the returned light to the optical element (18) (or (22)) and the refractive index N of the optical element, magneto-optical recording can be performed. Medium (
The phase difference δ, -1 caused in 1) can be canceled. Therefore, the conventional phase compensation plate (10) disposed in the return optical path is omitted.
以下、第１図乃至第３図を参照して本発明による光磁気
ピックアップ装置の実施例を説明する。Embodiments of the magneto-optical pickup device according to the present invention will be described below with reference to FIGS. 1 to 3.
第１図において、第４図と対応する部分には同一符号を
付して示すも、特に本例では第４図における位相補償板
（１０）を省略し、この位相補償の機能をレーザ光源（
６）から光磁気記録媒体である光磁気ディスク（１）へ
の往きの光路上に配したプリズムミラー（１８）に持た
せるようになすものである。In FIG. 1, parts corresponding to those in FIG. 4 are denoted by the same reference numerals, but in this example, the phase compensation plate (10) in FIG.
6) is held by a prism mirror (18) placed on the optical path from the magneto-optical disk (1), which is a magneto-optical recording medium.
即ち、本例においては、レーザ光源（１）からの光ビー
ムをコリメータレンズ（５）で平行光に変換し、ビーム
スブリック（４）で９０°方向反射し、さらに位相補償
を兼ねるプリズムミラー（１８）で９０°方向に反射さ
せ対物レンズ（２）を経て光磁気ディスク（１）上に集
光する。そして、光磁気ディスク（１）を反射した戻り
の光ビームをプリズムミラー（１８）で９０°方向に反
射させ、ビームスプリッタ（４）を透過した後、ビーム
スプリッタ（４）で２つの光ビームに分割し、一方の光
ビームを集光レンズ（８）を経てトラッキングサーボ、
フォーカスサーボ用のフォトダイオード（９）に入射せ
しめ、他方の光ビームを１７２波長板（１１）を経て偏
光ビームスプリッタ（１２）で２分し、夫々集光レンズ
（Ｈ） （１５）を介して第１フオトダイオード（１４
）及び第２フオトダイオード（１６）に入射し、差動検
出して再生信号を得るように構成される。That is, in this example, a light beam from a laser light source (1) is converted into parallel light by a collimator lens (5), reflected in a 90° direction by a beam brick (4), and is further provided with a prism mirror (18) that also serves as phase compensation. ), the light is reflected in a 90° direction and is focused on the magneto-optical disk (1) through the objective lens (2). The returning light beam reflected from the magneto-optical disk (1) is reflected in a 90° direction by a prism mirror (18), passes through a beam splitter (4), and is split into two light beams by a beam splitter (4). The light beam is split into two parts, and one of the light beams passes through a condensing lens (8) to a tracking servo.
The light beam enters a photodiode (9) for focus servo, and the other light beam passes through a 172 wavelength plate (11), is split into two by a polarizing beam splitter (12), and is split into two by a condenser lens (H) (15). First photodiode (14
) and a second photodiode (16), and is configured to perform differential detection to obtain a reproduced signal.
プリズムミラー（１８）は、α＝４５°の直角三角形を
なし、互いに直交する面（１９） （２０）に無反射コ
ート膜を形成し、４５°をなす裏面には無反射コート膜
を形成しないで、この空気との界面を反射面（２１）と
して構成される。プリズムミラー（１８）はビームスプ
リッタ（４）からの光ビームが面（１９）に垂直に入射
し、反射面（２１）で９０°方向に全反射されて面（２
０）より垂直に出射するように配される。The prism mirror (18) forms a right triangle with α=45°, and has anti-reflection coatings formed on the surfaces (19) and (20) that are perpendicular to each other, and no anti-reflection coating film is formed on the back surface forming the 45° angle. The interface with this air is configured as a reflecting surface (21). In the prism mirror (18), the light beam from the beam splitter (4) is incident perpendicularly on the surface (19), is totally reflected in the 90° direction on the reflection surface (21), and is reflected on the surface (2).
0) Arranged to emit more vertically.
光磁気ディスク（１）で反射した戻りの光ビームはこの
ディスク（１）によりＰ偏光成分とＳ偏光成分との位相
差δ、−１を生じ、位相差δｓ−ｐ は光磁気ディスク
に設けられる光磁気記録媒体（光磁気記録膜でも可）自
体の特性によって左右されるが現在の光磁気ディスクで
はこの位相差δｓ−ｐが３０ｄｅｇ程度である。一方上
述のプリズムミラー（１８）を構成するガラスとしてＢ
Ｋ−７を選ぶと、このプリズムミラー（１８）では位相
差δｐ−ｓ が３９°程度生じる。The returning light beam reflected by the magneto-optical disk (1) produces a phase difference δ, -1 between the P-polarized component and the S-polarized component by the disk (1), and the phase difference δs-p is provided on the magneto-optical disk. Although it depends on the characteristics of the magneto-optical recording medium (or a magneto-optical recording film) itself, in the current magneto-optical disk, this phase difference δs-p is about 30 degrees. On the other hand, as the glass constituting the above-mentioned prism mirror (18), B
When K-7 is selected, a phase difference δp-s of about 39° occurs in this prism mirror (18).
即ち、前述の式
を代入すると、δｐ−ｓ ＝３８．８ｄｅｇ ＞ ０
となる。That is, by substituting the above formula, δp-s = 38.8deg > 0
becomes.
第３図はこのときの入射角θ１を変化させたときの位相
差δ１．の変化を示すグラフである。FIG. 3 shows the phase difference δ1 when the incident angle θ1 is changed. It is a graph showing changes in.
上述の構成によれば、レーザ光源（６）から光磁気ディ
スク（１）への往きの光路では、プリズムミラー（１８
）の反射面（２１）に光ビームをＳ偏光で入射する。According to the above configuration, in the optical path from the laser light source (6) to the magneto-optical disk (1), the prism mirror (18
A light beam is incident on the reflective surface (21) of ) as S-polarized light.
次に光磁気ディスク〔１）で反射した戻りの光ビームが
プリズムミラー（１８）の反射面（２１）を通過する際
に、光磁気ディスク（１）で生じた楕円率（即ち位相差
δ、−１は３０ｄｅｇ程度）がプリズムミラー（１８）
のもつ位相差δｐ−ｓ ＝３８〜３９°で相殺され、よ
り直線偏光に近い状態に補正される。この効果は従来の
位相補償板のもつ効果に等しい。従って従来の位相補償
板を省略することができ、その分、省スペース化を図る
ことができること、従来の位相補償板の位置調整が不要
となること、さらにこの種の光磁気ピックアップ装置を
安価に提供することができる等の実益を有するものであ
る。Next, when the returning light beam reflected by the magneto-optical disk [1] passes through the reflective surface (21) of the prism mirror (18), the ellipticity (i.e., the phase difference δ) generated in the magneto-optical disk (1), -1 is about 30deg) is a prism mirror (18)
It is canceled out by the phase difference δp-s = 38 to 39 degrees, and is corrected to a state closer to linearly polarized light. This effect is equivalent to that of a conventional phase compensation plate. Therefore, the conventional phase compensation plate can be omitted, which saves space, eliminates the need to adjust the position of the conventional phase compensation plate, and makes this type of magneto-optical pickup device inexpensive. It has practical benefits such as being able to provide
なお、上側ではプリズムミラー（１８）としてガラス（
ＢＫ−７）を用いたが、適切な屈折率Ｎのガラスを選ぶ
ことによって、光磁気ディスク（１）で生じる位相差を
完全に打消ことが可能である。また第３図からもわかる
ようにディスク（１）からの戻り光の入射角θｌを選定
することによっても完全に打消ことが可能となる。In addition, on the upper side, a glass (
BK-7) was used, but by selecting a glass with an appropriate refractive index N, it is possible to completely cancel out the phase difference that occurs in the magneto-optical disk (1). Furthermore, as can be seen from FIG. 3, complete cancellation is also possible by selecting the incident angle θl of the return light from the disk (1).
尚、上側ではプリズムミラー（１８）を利用したが、第
２図に示すようにガラス平行平板を４５°に傾け、入射
面（２４）に無反射コート膜を形成し、裏面を反射面（
２３）とした光学素子（２２）を用いることもできる。Although a prism mirror (18) was used on the upper side, the parallel flat glass plate was tilted at 45 degrees as shown in Figure 2, a non-reflection coating film was formed on the incident surface (24), and the back surface was made into a reflective surface (24).
23) can also be used.
〔発明の効果〕゛
上述の本発明によれば、レーザ光源と光磁気記録媒体間
の光路にレーザ光源からの光ビームを全反射して所定方
向即ち光磁気記録媒体側に曲げるミラーを兼ねると共に
、光磁気記録媒体からの戻り光の位相補償を行う光学素
子を設けたことにより、従来の高価な位相補償板を省略
することができる。従って、ピックアップ装置全体の省
スペース化を図ることができると共に、位相補償板を配
したときの位置調整等も不要となり、光磁気ピックアッ
プ装置を安価に提供することができる。[Effects of the Invention] According to the above-described present invention, the optical path between the laser light source and the magneto-optical recording medium is provided with a mirror that totally reflects the light beam from the laser light source and bends it in a predetermined direction, that is, toward the magneto-optical recording medium. By providing an optical element that performs phase compensation of the return light from the magneto-optical recording medium, the conventional expensive phase compensation plate can be omitted. Therefore, the overall space of the pickup device can be saved, and position adjustment and the like when disposing the phase compensating plate are not required, and the magneto-optical pickup device can be provided at low cost.
第１図は本発明による光磁気ピックアップ装置の一例を
示す構成図、第２図は本発明に適用できる光学素子の他
の例を示す側面図、第３図は本発明に係る光学素子とし
てガラス（ＢＫ−７）によるプリズムミラーを用いた場
合の入射角θｌ と位相補償量即ち位相差δ、−５との
関係を示すグラフ、第４図は従来の光磁気ピックアップ
装置の例を示す構成図である。
（１）は光磁気ディスク、（３）はプリズムミラー、（
４）（７）はビームスプリフタ、（６）はレーザ光源、
（９）はサーボ用フォトダイオード、（１０）は位相補
償板、（１１）は１７２波長板、（１２）は偏光ビーム
スブリフタ、（１４） （１６）はフォトダイオード、
（１８）は本発明に係る位相補償機能を有するプリズム
ミラーである。
代 理 人 伊 藤 頁間
松 隈 秀 盛本を施用の構成図
イ１第１図
白棗イ列 め橋Ｘコ
第４図
り１９−FIG. 1 is a configuration diagram showing an example of a magneto-optical pickup device according to the present invention, FIG. 2 is a side view showing another example of an optical element applicable to the present invention, and FIG. (BK-7) is a graph showing the relationship between the angle of incidence θl and the amount of phase compensation, that is, the phase difference δ, -5, when a prism mirror is used. FIG. 4 is a configuration diagram showing an example of a conventional magneto-optical pickup device. It is. (1) is a magneto-optical disk, (3) is a prism mirror, (
4) (7) is a beam splitter, (6) is a laser light source,
(9) is a servo photodiode, (10) is a phase compensation plate, (11) is a 172 wavelength plate, (12) is a polarizing beam subrifter, (14) and (16) are photodiodes,
(18) is a prism mirror having a phase compensation function according to the present invention. Agent Paige Ito
Hide Matsukuma Configuration diagram using Morimoto
A1 Figure 1 White jujube A row Mebashi X-co 4th drawing 19-
Claims (1)
曲げて光磁気記録媒体上に上記光ビームを集束させる対
物レンズに導くと共に、上記対物レンズを介した上記光
磁気記録媒体からの戻り光の位相補償を行う光学素子と
、 上記光学素子を介して上記光磁気記録媒体からの戻り光
を受光する検出手段 を具備して成る光磁気ピックアップ装置。[Scope of Claims] A laser light source; a light beam from the laser light source is totally reflected, bent in a predetermined direction, and guided to an objective lens that focuses the light beam on a magneto-optical recording medium; A magneto-optical pickup device comprising: an optical element that performs phase compensation of the return light from the magneto-optical recording medium; and a detection means that receives the return light from the magneto-optical recording medium via the optical element.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63035561A JPH01211258A (en) | 1988-02-18 | 1988-02-18 | Magneto-optical pickup device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63035561A JPH01211258A (en) | 1988-02-18 | 1988-02-18 | Magneto-optical pickup device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01211258A true JPH01211258A (en) | 1989-08-24 |
Family
ID=12445154
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63035561A Pending JPH01211258A (en) | 1988-02-18 | 1988-02-18 | Magneto-optical pickup device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01211258A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6118748A (en) * | 1997-10-06 | 2000-09-12 | Fujitsu Limited | Optical information storage unit having phase compensation means for applying different phase compensation quantities with respect to signals detected from land and groove of recording medium |
-
1988
- 1988-02-18 JP JP63035561A patent/JPH01211258A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6118748A (en) * | 1997-10-06 | 2000-09-12 | Fujitsu Limited | Optical information storage unit having phase compensation means for applying different phase compensation quantities with respect to signals detected from land and groove of recording medium |
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