JPS6020322A - Optical disk pickup device - Google Patents
Optical disk pickup deviceInfo
- Publication number
- JPS6020322A JPS6020322A JP58127498A JP12749883A JPS6020322A JP S6020322 A JPS6020322 A JP S6020322A JP 58127498 A JP58127498 A JP 58127498A JP 12749883 A JP12749883 A JP 12749883A JP S6020322 A JPS6020322 A JP S6020322A
- Authority
- JP
- Japan
- Prior art keywords
- lens
- pickup device
- optical
- light
- optical system
- 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
- G11B7/0908—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 for focusing only
Abstract
Description
【発明の詳細な説明】
この発明は、光ディスク等の情報記録媒体から、情報を
光学的に読出す光デイスクピックアップ装置に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical disk pickup device that optically reads information from an information recording medium such as an optical disk.
第１図は従来の光デイスクピックアップ装置を示す斜視
図である。図においてｔｌｌは発光源としての半導体レ
ーザ、（２）は回尺格子、（３）は偏光ビームスプリッ
タ、（４）はコリメートレンズ、（５）は四分の一波長
板、（６１は対物レンズ、（７）は情報記録媒体である
光ディスク、（８）は拡大凹レンズ、（９１は円筒レン
ズ、 Ｑｌは光検知器、ａυはレンズｔ８１ ＋９７で
構成される焦点ずれ検出用光学系である。FIG. 1 is a perspective view showing a conventional optical disc pickup device. In the figure, tll is a semiconductor laser as a light emitting source, (2) is a grating, (3) is a polarizing beam splitter, (4) is a collimating lens, (5) is a quarter-wave plate, and (61 is an objective lens). , (7) is an optical disk which is an information recording medium, (8) is an enlarging concave lens, (91 is a cylindrical lens, Ql is a photodetector, and aυ is an optical system for detecting defocus, which is composed of a lens t81+97.
３つの光束に分けられ、コリメートレンズ（４）で３つ
の平行光束にされる。３つの平行光束は四分の一波長板
（５）を介し、対物レンズｉ６＋を通って光ディスク（
７）へと至り、光デイスク面上で微少な３つの集光スポ
ットを形成する。元ディスク（７）面上ＶＣハピットと
呼ばれる微少な凹凸がめシ、情報はこのビットの形で記
録されている。光ティスフは回転しておシ、そのため光
ディスクｆ７１に照射された光はピットによる変調を受
けて反射され、対物レンズ（６１に再入射し、対物レン
ズ（６）、四分の一波長板（５）、コリメートレンズ（
４）を介して逆戻シする。この光は偏光ビームスプリッ
タｔａ＋によって反射され。The light is divided into three beams and made into three parallel beams by a collimating lens (4). The three parallel light beams pass through the quarter-wave plate (5) and the objective lens i6+ onto the optical disc (
Step 7) forms three minute condensed spots on the optical disk surface. On the surface of the original disk (7) there are minute irregularities called VC pits, and information is recorded in the form of bits. The optical disc rotates, so the light irradiated onto the optical disc f71 is modulated by the pits and reflected, re-entering the objective lens (61), the objective lens (6), and the quarter-wave plate (5). ), collimating lens (
4). This light is reflected by the polarizing beam splitter ta+.
９０°方向を変えられて拡大凹レンズ（８）および円筒
レンズ（９７を順次通過して光検知器Ｏ１に到達する。The direction of the light is changed by 90 degrees, and the light passes sequentially through the magnifying concave lens (8) and the cylindrical lens (97) to reach the photodetector O1.
上記拡大凹レンズ＋８１及び円筒レンズ（９〕は、上記
光ディスク（７）上の集光スポットの焦点ずれを検出す
る光学系αＤを構成し９円筒レンズ（９）は、光検知器
叫上に、焦点がずれていなければ円形スポットに。The magnifying concave lens +81 and the cylindrical lens (9) constitute an optical system αD that detects the focal shift of the condensed spot on the optical disc (7). If it is not out of place, it will be a circular spot.
ずれていればずれの方向によシ円筒面軸方向又はこれに
直交する方向の何れかを長径とする楕円形スポットに集
光させるために用いられ、拡大凹レンズ（８）は、この
焦点のずれによる光検知器叫上の集光スポット形状の変
化の感度、即ち光学系の倍率を確保するために用いられ
る。光検知器−は。If there is a deviation, the magnifying concave lens (8) is used to focus the light on an elliptical spot whose major axis is either in the cylindrical surface axis direction or in a direction perpendicular thereto, depending on the direction of the deviation. This is used to ensure the sensitivity to changes in the shape of the focused spot on the photodetector, that is, the magnification of the optical system. Photodetector.
中央に４分割された有感領域１＋ Ｉを９両側に二つの
有感領域■、Ｉを有する６分割の検知器である。It is a 6-divided detector with 9 sensitive areas 1+I divided into 4 in the center and 2 sensitive areas 2 and I on both sides.
光ディスク（７）面上の３つの集光スポットのうち中央
のスポットに対応する反射光束ｅゴ有熱狽域群■に入射
し、各分割有感領域の総和受光信号を高周波記録情報信
号として、４分割の対角線上のそれぞれ２個の有感領域
の受光差信号を、フォーカシング信号として取出される
。即ち有感領域群Ｉの集光スポットが円形であれば受光
差信号は零、楕円であればそれの長径方向の対角線上の
２閏の有感領域受光信号が最大となシ正又は負の差信号
が得られ、焦点のずれ方向による極性でずれの大きさに
比例した大きさのフォーカシング信号が得られる。この
信号は対物レンズ（６１を光軸方向に制御するために用
いられる。また、光ディスク（７）面上の３つの集光ス
ポットの残シの２つからの反射光は、それぞれ有感領域
■、ｌに入射し、この２ ｖｉｔ域の受光差信号として
トラッキング信号が得られる。この信号は、光ディスク
（７）面上の集光スポットがビット列を正しく追従する
よう、対物レンズ（６）を光ディスク（７）の半径方向
に制御するために用いられる。The reflected light beam corresponding to the central spot among the three focused spots on the surface of the optical disk (7) enters the thermal sensitive area group ■, and the total light reception signal of each divided sensitive area is used as a high frequency recording information signal. Light reception difference signals of two sensitive areas on each diagonal of the four divisions are extracted as focusing signals. That is, if the focused spot of sensitive area group I is circular, the received light difference signal is zero, and if it is elliptical, the sensitive area received signals of two diagonals in the long axis direction are the maximum, and the positive or negative difference signal is zero. A difference signal is obtained, and a focusing signal whose polarity depends on the direction of focus shift and whose magnitude is proportional to the magnitude of shift is obtained. This signal is used to control the objective lens (61) in the optical axis direction.In addition, the reflected light from the remaining two of the three focused spots on the surface of the optical disk (7) is , l, and a tracking signal is obtained as a received light difference signal in the 2 vit range. (7) Used to control in the radial direction.
以上のように従来の光ピツクアップ装置は、充分な焦点
ずれ検出感度を上げるために、焦点ずれ検出用光学系α
υとして円筒レンズ（９）の他、拡大凹レンズ（８）を
使用しているので光ピツクアップ装置の小型・＠量・低
価格化には難点があった。また経年変化等の理由によシ
拡太凹レンズ（８）１円筒レンズ（９；の相対位置が狂
いピックアップ装置の信頼性が低下するという欠点があ
った０
この発明は、上記のような従来の欠点を除去するために
なされたもので、上記拡大レンズと円筒レンズを１個の
光学部品で構成し上記両レンズの作用とそれぞれもつ２
つの要素の両方もしくけ一方をフレネルレンズとして、
上記光学部品の両面もしくは一面側に構成させることに
より、小形・軽量・低価格かつ信頼性の高い光ピツクア
ップ装置を提供するものである。As described above, in order to increase sufficient defocus detection sensitivity, conventional optical pickup devices use an optical system α for defocus detection.
Since a magnifying concave lens (8) is used in addition to the cylindrical lens (9) as υ, it is difficult to reduce the size, quantity, and cost of the optical pickup device. In addition, due to aging, etc., the relative positions of the expanding concave lens (8) and the cylindrical lens (9) become erroneous, reducing the reliability of the pickup device. This was done in order to eliminate the drawbacks, and the magnifying lens and cylindrical lens are constructed from one optical component, and the two lenses each have the functions of both lenses.
Both of these elements work together, and one is used as a Fresnel lens.
By configuring the above-mentioned optical components on both sides or one side, it is possible to provide an optical pickup device that is small, lightweight, low cost, and highly reliable.
以下第２図、第３図により、この発明の１実施例を説明
する。第２図は、この発明の１実施例である光デイスク
ピックアップ装置を示す斜視図でｉｌｌ〜（１（ｌは第
１図と同様の（６成であシ、同一符号は同−或は相当部
分を示している。０ｚはｇ１図の拡大凹レンズ（８）９
円筒面レンズ（９Ｊからなる焦点ずれ検出用光学系ａυ
と同様の作用を行なう焦点ずれ検出用フレネルレンズ系
である。これはガラス平面板ａ３の一面α４１側に、拡
大凹レンズと同じ作用をもつフレネルレンズα９を、ま
た他面ｏｅ側に９円筒レンズと同じ作用をもつフレネル
レンズ（１７１を、電子ビーム露光装置を使って第３図
Ａ、Ｂに示すよう描画したものである。An embodiment of the present invention will be described below with reference to FIGS. 2 and 3. FIG. 2 is a perspective view showing an optical disk pickup device which is an embodiment of the present invention. 0z is the magnifying concave lens (8) 9 in figure g1.
Optical system for defocus detection consisting of a cylindrical lens (9J)
This is a Fresnel lens system for detecting defocus that performs the same function. A Fresnel lens α9, which has the same effect as an enlarging concave lens, is placed on one side α41 of the flat glass plate a3, and a Fresnel lens (171), which has the same effect as a cylindrical lens 9, is placed on the other side OE, using an electron beam exposure device. It is drawn as shown in FIGS. 3A and 3B.
このように従来拡大凹レンズ（８）１円筒レンズ（９１
と二つの光学部品が必要だったものを、焦点ずれ検出用
フレネルレンズ系ＵＺ−個で済ませたため。In this way, the conventional magnifying concave lens (8), 1 cylindrical lens (91
Instead of requiring two optical components, we now only need one Fresnel lens system for defocus detection.
光ピツクアップ装置の小型・ａｔ・低価格化が実現でき
る。また、経年変化・環境変化・衝撃等に起因する拡大
凹レンズと円筒レンズの相対位置ずれもなくなシ、光ピ
ックアップ装置全体の信頼性も向上する。Optical pickup devices can be made smaller, AT, and lower in price. Further, there is no relative positional shift between the magnifying concave lens and the cylindrical lens due to aging, environmental changes, shocks, etc., and the reliability of the entire optical pickup device is improved.
なおフレネルレンズ作成法の１具体例としては。Here is a specific example of the Fresnel lens making method.
ガラス平面板に電子ビームレジスト（ＰＭＭＡ） をス
ピンコードし、上からコンピュータ制御された電子ビー
ム露光装置でフレネルレンズの輪帯に対応するパターン
を描画する方法が知られている０（電子通信学会論文誌
８１／１０ ｖｏｌ、 Ｊ６４−０４１０ｐｐ ６５２
〜６５１）
上記実施例ではガラス平面板００両面ＱＩ Ｏｆｆにフ
レネルレンズａ■ηを描画したが第４図に示すように拡
大凹レンズとして平凹レンズ（Ｉ＆を用いる場合それの
平面（１９１１１１に円筒レンズと同じ作用をもつフレ
ネルレンズαηを描画してもよい。A known method is to spin-code an electron beam resist (PMMA) on a flat glass plate and draw a pattern corresponding to the annular zone of a Fresnel lens using a computer-controlled electron beam exposure device from above (IEICE paper). Magazine 81/10 vol, J64-0410pp 652
~651) In the above embodiment, a Fresnel lens a■η was drawn on both sides of the glass plane plate 00 QI Off, but as shown in FIG. A Fresnel lens αη having the same effect may be drawn.
また、第５図に示すように片面が平面な円筒レンズ（４
）を用い、その平面ＱＤ側に拡大凹レンズと同じ作用を
もつフレネルレンズａ９を描画してもよい。In addition, as shown in Fig. 5, a cylindrical lens with one side flat (4
), and a Fresnel lens a9 having the same effect as the enlarging concave lens may be drawn on the plane QD side.
以上のように、この発明によれば拡大凹レンズ。As described above, the present invention provides a magnifying concave lens.
円筒レンズの両方もしくは一方をフレネルレンズ化する
よう構成したので、光ピツクアップ装置が小型・軽量に
でき、安価で信頼性の高いものが得られるというすぐれ
た効果を有している。Since one or both of the cylindrical lenses is constructed as a Fresnel lens, the optical pickup device can be made small and lightweight, and has the excellent effects of being inexpensive and highly reliable.
第１図は従来の光デイスクピックアップ装置を示す斜視
図、第２図はこの発明の１実施例を示す斜視図、第３図
Ａ、Ｂは、それに使用される焦点ずれ検出用フレネルレ
ンズ系の第２図矢印Ａ及びＢ側から見た図、第４図、第
５図はそれぞれこの発明の他の実施例において使用され
る焦点ずれ検出用光学系を示す図、各図のＡは同図Ｂ矢
印Ａ側から見た図、各図のＢは仙ｊ面図である。
図中（１）は発光源としての半纏体レーザ、（３）は偏
光ビームスプリッタ、（６１は対物レンズ、（７）は情
報記録媒体である光ディスク、 （１０１は光検知器、
αＵＵＺは焦点ずれ検出用光学系、 （１５１は拡大凹
レンズと同じ作用をもつフレネルレンズ、０７Ｉは円筒
レンズと同じ作用をもつフレネルレンズである。
代理人 大 岩 増 雄（ほか２名）
−１ν 重 ロ凌−
１２１
（Ａ）
負
（Ａ）
１２０
４図
（８）
〜５図
（８）
、／（／ ２１FIG. 1 is a perspective view showing a conventional optical disk pickup device, FIG. 2 is a perspective view showing an embodiment of the present invention, and FIGS. 3A and 3B show a Fresnel lens system for detecting defocus used therein. FIG. 2 is a view seen from the arrow A and B sides, and FIGS. 4 and 5 are views showing optical systems for detecting defocus used in other embodiments of the present invention, and A in each figure is the same view. B is a view seen from the arrow A side, and B in each figure is a sacroplane view. In the figure, (1) is a semi-enveloped laser as a light emitting source, (3) is a polarizing beam splitter, (61 is an objective lens, (7) is an optical disk as an information recording medium, (101 is a photodetector,
αUUZ is an optical system for detecting defocus, (151 is a Fresnel lens that has the same effect as a concave magnifying lens, and 07I is a Fresnel lens that has the same effect as a cylindrical lens. Agent Masuo Oiwa (and 2 others) -1ν heavy Lo Ryo - 121 (A) Negative (A) 120 Figure 4 (8) - Figure 5 (8) , / ( / 21
Claims (1)
に集光する対物レンズ、上記記録媒体上に集光され反射
された光を上記発光源方向とは異なった方向に分離する
偏光ビームスプリッタ、この分離された反射光から上記
情報記録媒体上の上記対物レンズによる集光の焦点ずれ
を検出する焦点ずれ検出用光学系、及びこの光学系をへ
た上記反射光を受光する光検知器とを備えた光デイスク
ピックアップ装置において、上記焦点ずれ検出用光学系
として１個の光学部品を使用し、それぞれ凹レンズ、円
筒レンズの作用をもつ２つの要素の両方もしくは一方を
、フレネルレンズとして上記１１固の光学部品の画面も
しくは一面側に構成させ、この１個の光学部品に上記凹
レンズ、円筒レンズの両方の作用をもたせたことを％徴
とする光デイスクピックアップ装置。 （２）上記焦点すれ検出用光学系は、ガラス平面板の１
而仙に凹レンズと同じ作用笛もっフレネルレンズを、他
面１＃に円面レンズと同じ作用をもつフレイルレンズを
そ扛ぞれ作成ざぜて構成させた特許請求の範囲第１項記
載の光デイスクピックアップ装置。 １３＋ 上記焦点ずれ検出用光学系は、平凹レンズの平
面側に円筒レンズと同じ作用勿もつフレネルレンズを作
成させて構成させた特許請求の範囲第１項記載の光デイ
スクピックアップ装置。 （４） 上記焦点ずれ検出用光学系は、１面が円筒面で
他面が平面をなす円筒レンズの平面側に凹レンズと同じ
作用をもつ１＋≠肴フレネルレンズを作成させて構成さ
せた特許請求の範ｌ（第１ＪＡ記載の光ティスフピック
アップ装置。 （５） 上記フレネルレンズは、上記光学部品面上に電
子ビーム露光装置を用いて描画することにより作成した
特許請求の範囲第１項ないし第４項記載の元ディスクピ
ックアップ装置。[Claims] fi+ Light emitting source, light from this light emitting source? An objective lens that focuses light onto the information recording medium, a polarizing beam splitter that separates the light focused and reflected onto the recording medium into a direction different from the light emitting source direction, and the information recording from this separated reflected light. In an optical disk pickup device, the optical disk pickup device includes a defocus detection optical system that detects a defocus of light condensed by the objective lens on a medium, and a photodetector that receives the reflected light that has passed through this optical system. One optical component is used as an optical system for detecting deviation, and both or one of two elements having the functions of a concave lens and a cylindrical lens, respectively, is configured as a Fresnel lens on the screen or one side of the above-mentioned 11 optical components. An optical disk pickup device characterized by having this one optical component function as both the concave lens and the cylindrical lens. (2) The above-mentioned optical system for detecting out-of-focus is one of the flat glass plates.
The optical disk according to claim 1, wherein a Fresnel lens has the same effect as a concave lens on one side, and a flail lens has the same effect as a circular lens on the other side. pickup device. 13+ The optical disk pickup device according to claim 1, wherein the optical system for detecting defocus is constructed by creating a Fresnel lens having the same function as a cylindrical lens on the plane side of a plano-concave lens. (4) The above-mentioned optical system for detecting defocus is constructed by creating a 1+≠Fresnel lens having the same effect as a concave lens on the flat side of a cylindrical lens whose one surface is a cylindrical surface and the other surface is a flat surface. (5) The Fresnel lens is created by drawing on the surface of the optical component using an electron beam exposure device. The original disk pickup device described in item 4.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58127498A JPS6020322A (en) | 1983-07-13 | 1983-07-13 | Optical disk pickup device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP58127498A JPS6020322A (en) | 1983-07-13 | 1983-07-13 | Optical disk pickup device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS6020322A true JPS6020322A (en) | 1985-02-01 |
Family
ID=14961453
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP58127498A Pending JPS6020322A (en) | 1983-07-13 | 1983-07-13 | Optical disk pickup device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6020322A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6235421U (en) * | 1985-08-16 | 1987-03-02 | ||
| JPH01282751A (en) * | 1988-05-06 | 1989-11-14 | Mitsubishi Electric Corp | Optical head device |
| US6475461B1 (en) * | 1995-03-30 | 2002-11-05 | Nippon Sanso Corporation | Porous carbonaceous material, manufacturing method therefor and use thereof |
-
1983
- 1983-07-13 JP JP58127498A patent/JPS6020322A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6235421U (en) * | 1985-08-16 | 1987-03-02 | ||
| JPH01282751A (en) * | 1988-05-06 | 1989-11-14 | Mitsubishi Electric Corp | Optical head device |
| US6475461B1 (en) * | 1995-03-30 | 2002-11-05 | Nippon Sanso Corporation | Porous carbonaceous material, manufacturing method therefor and use thereof |
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