JPS5936337A - Optical head - Google Patents
Optical headInfo
- Publication number
- JPS5936337A JPS5936337A JP57144462A JP14446282A JPS5936337A JP S5936337 A JPS5936337 A JP S5936337A JP 57144462 A JP57144462 A JP 57144462A JP 14446282 A JP14446282 A JP 14446282A JP S5936337 A JPS5936337 A JP S5936337A
- Authority
- JP
- Japan
- Prior art keywords
- light
- photodetector
- lens
- layer
- cells
- 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
Classifications
-
- 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
Landscapes
- Optical Head (AREA)
Abstract
Description
【発明の詳細な説明】
〔発明の技術分野〕
本発明は集光したレーザ光により情報記録媒体から少な
くとも情報を読取ることがＩＩ］′能なハ］２録再生用
の光学ヘッドに関する。DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an optical head for recording/reproduction that is capable of reading at least information from an information recording medium using a focused laser beam.
情報記録媒体の記録層ないしは光反射Ｉ−上で集光した
レーザ光全照射した位置に対する光学的結像位置に１個
の光検出器全役りてフ（−カサスゲケおよびトラックず
れ全検出する光学系が知られている。A single photodetector is placed at the optical imaging position for the position where the laser beam focused on the recording layer or light reflection I of the information recording medium is fully irradiated. system is known.
この種の光学系において、たとえば第１図に示したよう
に記録層ないしは光反射層、ヒでフォーカザスが合って
いる場合には、４個の光検出セルフ ａ ｒ ７ ｂ
ｙ ７ ｃ ＋ ７ ｄ ｆ所定間隔を存して配設して
なる光検出器７−Ｈのビームス、Ｉ？アット７を光分小
さくして光検出器７中のギヤ、）１６中に入れた方がフ
ォーカザスビケ検出イｄ−号として光検出器７上の結像
・Ｐターン（時によっては回折・母ターン）の影響を受
けにくく安定する。In this type of optical system, for example, as shown in FIG. 1, when the recording layer or the light reflecting layer is in focus, four photodetecting self-detectors a r 7 b
y 7 c + 7 d f The beams of the photodetectors 7-H arranged at predetermined intervals, I? It is better to reduce the at 7 by a light amount and put it in the gear ( ) 16 in the photodetector 7, which will serve as a focuser for detection of image formation on the photodetector 7, P turn (in some cases, diffraction, mother turn). ) and is stable.
しかしながら、従来においてはトラ、りずれ検出方向２
２に対してもビームス７Ｊ？ツト１７が光検出器ｚ中の
−Ｖ°ヤッ７’ Ｊ ６内に入るため、トラックずれ検
知ができない。However, in the past, the
Beams 7J for 2 too? Since the point 17 enters within -V°Y7'J6 of the photodetector z, track deviation cannot be detected.
また、情報記録媒体の記録ｂ’ｉないしは）′ｏ反射層
上での凹凸形状変化によりトラッキングガイドが形成さ
れている場合にはその位置に対する光学的結１象位ＩＰ
″ＴＫＩ−ラックずれ検出用検知器を置いても大きなト
ラックずれ検出信号を得ることができない。ｊ市常凹凸
形状のトラッキングガイドは幅０６μｍ位のオーダの非
常な倣細なｙｔ遺をしているため、そこから反射した高
次の回折光は集光レンズの開１」に制限され、光学的結
像面上ではコントラストの良いドラッギングパターンを
得ることができないためと考えら扛る。In addition, if a tracking guide is formed by a change in the uneven shape on the recording b'i or )'o reflective layer of the information recording medium, the optical convergence point IP for that position is
Even if a TKI-rack deviation detection detector is installed, it is not possible to obtain a large track deviation detection signal.The tracking guide, which has a regular uneven shape, has a very narrow profile with a width of about 06 μm. This is thought to be due to the fact that the high-order diffracted light reflected therefrom is limited to the aperture of the condenser lens, making it impossible to obtain a dragging pattern with good contrast on the optical imaging plane.
また、記録層ないしは光反利層−ヒでの光反射率の違い
によりトラッキングガイドが形成さ扛る場合にも類似し
たことがＴイえる。A similar situation can also be observed when a tracking guide is formed due to a difference in light reflectance between the recording layer or the light reflection layer.
本発明は上記事情に着目してなされたもので、その目的
とするところは、記録媒体情報の記録層ないしは光反射
層の傾きや、そこから反射さ扛た光の回折・ぞターンに
影響を受けることなく安定してフォーカス制御が可能で
あるとともにトラッキングずれ検出信号も充分に大きな
ものが得らｎ’−シかもフォーカスバεケおよびトラッ
キングずｎ検出を一個の光検出器の中で行なうことがで
きるようにした光学ヘッドを提供しようとするものであ
る。The present invention has been made in view of the above-mentioned circumstances, and its purpose is to reduce the influence of the inclination of the recording layer of information on a recording medium or the light reflecting layer, and the diffraction and rotation of light reflected therefrom. In order to be able to stably control the focus without any interference and to obtain a sufficiently large tracking deviation detection signal, focus adjustment and tracking deviation detection should be performed in one photodetector. The present invention aims to provide an optical head that can perform the following functions.
本発明は情報記録媒体の記録層ないしは光反射層上に照
射される集光されたレーデ光の照射点に対する）°Ｃ学
的結像位ｉｅ：ｆ、に光検出器を備えたものにおいて、
前記情報記録媒体の記録層ないしは光反射層と前記光検
出器との間にンリンドリカルレンズを設け、前記光検出
器トに楕円形状のビームスポ、トヲ形成するものである
。The present invention provides a device equipped with a photodetector at an imaging position (ie: f) in °C with respect to the irradiation point of the condensed Rede light irradiated onto the recording layer or light reflection layer of an information recording medium.
An lindrical lens is provided between the recording layer or light reflection layer of the information recording medium and the photodetector, and an elliptical beam spot is formed on the photodetector.
〔発明の実施例Ｊ
以下、本発明の一実施例を第２図にもとづいて説明する
１、図中２は情報記録媒体の記録層ないしけ）“Ｌ反射
層で、この記録層（光反射層）２には対物レンズ３が離
間対向されている。前記７１物レンズ３の光軸３３上に
は所定間隔を存してλ／４板１２、偏光ビームスプリッ
タ１１、球面レンズ２４、シリンドカル凹レンズ２７、
三角グリズム２８、光検出器７が配設されている。[Embodiment J of the Invention Hereinafter, an embodiment of the present invention will be explained based on FIG. The objective lens 3 is spaced apart and opposed to the layer 2. On the optical axis 33 of the 71-object lens 3, a λ/4 plate 12, a polarizing beam splitter 11, a spherical lens 24, and a cylindrical concave lens are arranged at a predetermined interval. 27,
A triangular grism 28 and a photodetector 7 are provided.
士た、上記偏光ビームスプリ、り１１の一上方部にＣ」
、コリメータレン７゛３１が設けられ、さらに、この＝
１リメータレンズ３１の一ヒ万部には半導体レーデ”３
０が１投けら′ｔｔている。寸た、上記１ａ報記録媒体
の、−１〕録層ないしは）Ｙ−反射層２には所定間隔を
存してトラッキングガイド２３・・が形成さ扛ている。At the top of the polarized beam splitter 11,
, a collimator lens 7゛31 is provided, and furthermore, this =
One million parts of the 1 meter lens 31 have a semiconductor radar of 3
There is one 0 thrown. In addition, tracking guides 23 are formed at predetermined intervals on the -1] recording layer or) Y-reflection layer 2 of the 1a information recording medium.
まｆｒＸ ト記光検出器７け６個の光検出セルフａ、
７ｈ、７ｃ、７ｄ、７ｅ、７ｆによって（１゛〜成さ扛
ている。MafrX 7 photodetectors 6 photodetection self a,
7h, 7c, 7d, 7e, and 7f (1゛ ~ is formed.
しかして、上Ｉ７ドシ化構成において、半導体レーデ°
３０からレーザ光３２″ｆＫ：発揚させると、レージ’
；？ ２はコリメータレンズ３１を経て平行光となシ、
偏光ビームスプリッタ１）で反射し、λ／４板１２金通
過して円偏光となって記録層ないしは光反射層２に照射
される。そして、その反射光は対物レンズ３、λ／４板
１２、偏光ビームス−ｆリッタ１１全通過したのち、球
面レンで２４、シリンドリカル凹レンズ２７、三角ｆリ
ズム２８を介して光検出器７に到達する。Therefore, in the upper I7 configuration, the semiconductor radar
Laser light from 30 to 32″ fK: When launched, the laser beam
;? 2 becomes parallel light after passing through the collimator lens 31;
The light is reflected by the polarizing beam splitter 1), passes through the λ/4 plate 12 gold, becomes circularly polarized light, and is irradiated onto the recording layer or the light reflection layer 2. Then, the reflected light passes through the objective lens 3, the λ/4 plate 12, and the polarization beam filter 11, and then reaches the photodetector 7 via the spherical lens 24, the cylindrical concave lens 27, and the triangular f-rhythm 28. .
ところで、この光検出時においてはシリンドリカル凹レ
ンズ２７の作用によす、ビーノ・ス、Ｉ？ット１７がフ
ォーカスｒｆケに応じて移・（のする）ｊ向に対し、直
角方向に引き伸ばさルｈ円形吠を呈するとともにトラッ
クずｆＬ検検出内向ら（ｚ、ると、記録層ないしは光反
射層２に対する結像点は光検出器７から帷れたｆｊ″Ｌ
置に存在し、光検出器７上では記録層ないしは光反射層
２に対する回折・Ｐターンが観察さ７’Ｌる。しかして
、トラ。By the way, during this light detection, the effect of the cylindrical concave lens 27 is used. The track 17 moves in response to the focus rf and is stretched in a direction perpendicular to the j direction. The imaging point for layer 2 is fj″L extending from photodetector 7.
On the photodetector 7, diffraction/P-turn with respect to the recording layer or the light reflection layer 2 is observed. However, the tiger.
ギングガイド２，７・・を横切る時の回折・Ｐターンの
変化方向が矢印２２のようになるから、光検出セルフ
ａ ＋ ７ ｂ ｇ ７ ｃの受光量全トータルした値
と光検出セルフ ｄ ｒ ７ ｅ ｒ ７ ｆの受光Ｘ
Ｉ、 ’ｌｒトータルした値との差によりトラックずれ
が検出され、オた、フォーカスボケの変化方向は矢印２
２と直交する方向になるから、光検出セルフｂ、７ｅの
受うＹ；量をトータルした値と光検出セルフａ、７ｃ、
７ｆ、７ｅの受光量ヲトータルした値との差によりフォ
ーカスボケが検出されることになる。Since the direction of change of diffraction/P-turn when crossing the ging guides 2, 7, etc. is as shown by arrow 22, the photodetection self
Total value of received light amount of a + 7 b g 7 c and photodetection self d r 7 e r 7 f received light X
Track deviation is detected by the difference between I and 'lr total value, and the direction of change of focus blur is indicated by arrow 2.
Since the direction is perpendicular to 2, the Y received by photodetection self b, 7e; the total value of the amount and photodetection self a, 7c,
Out-of-focus is detected based on the difference between the total amount of light received at 7f and 7e.
なお、４二記−実施例においては光検出器７の前にシリ
ンドカル凸レンズ２７を設けたが、これに限らｎ、るこ
となく、第３図に示すようにシリンドカル凸レンズ２５
ｆ：設ケ、対物レンズ１２させるミラーである。この実
施例において光検出器７ＩＪ第１図に示したものと同様
に構成さ扛るが、第１図のもの２４５°傾けた状態で設
けられ、トラックず２′Ｖ、は光Ａ曳出セルフｂ 、７
ｄにより検出し、フォーカスボケは光検出セルフａ。Although the cylindrical convex lens 27 is provided in front of the photodetector 7 in Section 42-Embodiment, the cylindrical convex lens 27 is not limited to this, and as shown in FIG.
f: A mirror for the objective lens 12. In this embodiment, the photodetector 7IJ is constructed in the same manner as that shown in FIG. b, 7
d, and out of focus is detected by photodetection self a.
７ｃによりｔ倉出する。According to 7c, t stock is taken out.
捷た、上記一実施例においては対物レンズ３の光軸３３
に対して直交する角１隻でレーザ光ヲ入射させたが、こ
ｒしに限らｔ″Ｌること・ｔく、第５図に示すように、
対物レンズ３の光軸３３に対して傾いた角度でレーザ光
全入射させるようにしてもよい。In the above embodiment, the optical axis 33 of the objective lens 3
Although the laser beam was incident at one corner perpendicular to
The entire laser beam may be made incident at an angle oblique to the optical axis 33 of the objective lens 3.
本発明は以−ヒ説明したように、情報記録媒体の記録層
ないしは光反射層と光検出器との間に少なくとも一個の
シリンドリカルレンズを設け、光検出器上に楕円形のビ
ームスポットｆ形成したから、トラックずｔｔ検出方向
でのビーノ・スポットのサイズは光検出器のギャッノよ
りも友きくとれ、トラックずれ検出信号を充分に大きく
取ることができる。また、トラックずｎ１ｔ２、トラッ
キングガイドに対する回折パターンで検出するため、凹
凸形状のトラッキングガイドの場合には結像・やターン
よりもトラックずれに対する検出出力を大きくと扛確実
にトラックずれを検出できる。また、フォーカスづ？ケ
検出力向に対しては＠像位置に光検出器を設けるから、
）℃検出器上でのビームス７ｆｆ７トｉ充分に小さくし
て各光検出器セル間のギヤラグ内に入１２ることかでき
、集光されたレーザースボ７）が情報記録媒体の配録層
ないしは光反射層にあるトラッキングプｆイド￥横切っ
たときに生ずる光検出器上のビームス７１ピツト内の結
像（回折）・Ｐターンによるフォーカス列？ケ検出信号
への悲影響をまったく除去することができる。４Ｆ、た
、情報記録媒体の而ぶｆＬにより、記録層ないしは光反
射層が傾いたり、トラッキング補正用に対物レンズ゛が
移動（〜てもその影グｌＩを受けｌ“、ケ定Ｌ７た）Ａ
−カス刺りができろとともにレーザ光の光路の途中１／
Ｃ−！ミの付青やレンズ面−Ｈの１％があったとしても
ｔ １１． Ｋ工りフォープノスが乱さ才することがな
い。As explained below, the present invention provides at least one cylindrical lens between the recording layer or the light reflection layer of the information recording medium and the photodetector, and forms an elliptical beam spot f on the photodetector. Therefore, the size of the Beano spot in the track deviation tt detection direction is smaller than that of the photodetector, and the track deviation detection signal can be obtained sufficiently large. In addition, since the track deviation n1t2 is detected by the diffraction pattern for the tracking guide, in the case of an uneven tracking guide, the detection output for the track deviation is larger than that for imaging/turning, so that the track deviation can be detected reliably. Also, focus? For the detection force direction, a photodetector is installed at the image position, so
) The beam 7ff7 on the detector can be made small enough to enter the gear lag between each photodetector cell, and the focused laser beam 7ff7) can be transmitted to the recording layer of the information recording medium or the light beam. Imaging (diffraction) in the beam 71 pit on the photodetector that occurs when the tracking prism crosses the reflective layer.Focus line due to P-turn? Therefore, any negative influence on the detection signal can be completely eliminated. 4F, due to fL of the information recording medium, the recording layer or the light reflection layer may be tilted, or the objective lens for tracking correction may be moved (even if the effect is affected by the fL, it is determined L7). A
- Along with the formation of scraps, the middle part of the optical path of the laser beam is 1/
C-! Even if there is 1% of blue with yellow or lens surface -H, t 11. K-crafted Forpnos will never be disturbed.
第１図１ｔ２、ビームスポットが充分小さいときの光検
出器上のパターンを示す説明図、第２図は本発明の一フ
竪施例である光学ヘッド金示す概略的＋７１、成図、第
３図（ｒｌ一本発明の第１の他の実施例を示す概略的構
成図、第４図はその光検出器を示す正面図、第５図は本
発明の第２の１ｌｊＪの実施例全示す概略的構成図であ
る。
２・・・記録層ない【２はブＣ反射層、７・・・光検出
器、１７・・・ビームスポット、２５．２７・・・シリ
ンドリカルレンズ１、
出願人代理人 弁理士 鈴 江 弐 ρ第３図
第５図
１７９−Fig. 1t2 is an explanatory diagram showing the pattern on the photodetector when the beam spot is sufficiently small; Fig. 2 is a schematic diagram showing the optical head which is a vertical embodiment of the present invention; FIG. 4 is a front view showing the photodetector of the first other embodiment of the present invention, and FIG. 5 is a full view of the second embodiment of the present invention. It is a schematic configuration diagram. 2...No recording layer [2 is a reflective layer, 7... Photodetector, 17... Beam spot, 25.27... Cylindrical lens 1, Applicant's representative Person Patent Attorney Suzue Ni ρFigure 3Figure 5 179-
Claims (4)
照射される集光されたレーリ′光の照射点に対する光学
的結像位置に光検出器を備えたものにおいて、前記情報
記録媒体の記録層ないしは光反射層と前記光検出器との
間にシリンドリカルレンズ全６：′ｌけ、前記光検出器
ヒに（貨円形状のビームス、Ｉ？ワット１杉成した仁と
を特徴とする光学ヘッド。(1) A photodetector is provided at an optical imaging position with respect to the irradiation point of the focused Rayleigh' light irradiated onto the recording layer or light reflection layer of the information recording medium, in which the recording layer or the light reflection layer of the information recording medium is A cylindrical lens is provided between the light-reflecting layer or the light-reflecting layer and the photodetector; head.
リズノ・全設けたこと全特徴とする特許請求の範囲第１
項記、（Ｉνの光学ヘッド。(2) Claim 1, which is characterized by all the features provided between the cylindrical lens and the photodetector.
Entry, (Iv optical head.
ーリ゛光を入射させること全特徴とする特許請求の範囲
第１項記載の光学ヘッド。(3) The optical head according to claim 1, characterized in that the optical axis is shifted in advance with respect to the optical axis of the objective lens and the Rayleigh light is incident thereon.
デ光を入射させたこと全特徴とする特許請求の範囲第１
項記載の光学へ、ド。(4) Claim 1, which is characterized in that the Raded light is incident at an angle oblique to the optical axis of the objective lens.
To the optics described in the section, de.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57144462A JPS5936337A (en) | 1982-08-20 | 1982-08-20 | Optical head |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57144462A JPS5936337A (en) | 1982-08-20 | 1982-08-20 | Optical head |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS5936337A true JPS5936337A (en) | 1984-02-28 |
Family
ID=15362825
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57144462A Pending JPS5936337A (en) | 1982-08-20 | 1982-08-20 | Optical head |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5936337A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0336419A2 (en) * | 1988-04-07 | 1989-10-11 | Insite Peripherals, Inc. | Apparatus and method for optical servo control with media having information storage and servo control regions of different reflectivities |
| US5737297A (en) * | 1996-06-21 | 1998-04-07 | Sharp Kabushiki Kaisha | Optical head |
-
1982
- 1982-08-20 JP JP57144462A patent/JPS5936337A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0336419A2 (en) * | 1988-04-07 | 1989-10-11 | Insite Peripherals, Inc. | Apparatus and method for optical servo control with media having information storage and servo control regions of different reflectivities |
| US5737297A (en) * | 1996-06-21 | 1998-04-07 | Sharp Kabushiki Kaisha | Optical head |
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| JPS58147821A (en) | Optical head | |
| JPS641858B2 (en) | ||
| JPS5954041A (en) | Optical head | |
| JPS639305B2 (en) | ||
| JPH0323977B2 (en) | ||
| JPH0242647A (en) | Optical pick-up device | |
| JPS63251942A (en) | Focusing error detector | |
| JPS60140553A (en) | Optical pickup | |
| JPH01149231A (en) | Optical pick-up | |
| JPH0249227A (en) | Structure of optical head | |
| JPH04143935A (en) | Optical pickup device |