JPS583140A - Focus controlling signal detector in optical information recorder and reproducer - Google Patents
Focus controlling signal detector in optical information recorder and reproducerInfo
- Publication number
- JPS583140A JPS583140A JP10176781A JP10176781A JPS583140A JP S583140 A JPS583140 A JP S583140A JP 10176781 A JP10176781 A JP 10176781A JP 10176781 A JP10176781 A JP 10176781A JP S583140 A JPS583140 A JP S583140A
- Authority
- JP
- Japan
- Prior art keywords
- information medium
- light
- photodetectors
- reflected beam
- photodetector
- 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
Landscapes
- Automatic Focus Adjustment (AREA)
- Optical Recording Or Reproduction (AREA)
Abstract
Description
【発明の詳細な説明】
本発明は光学的情報記録、再生装置において、情報媒体
に照射する光ビームの照射スポット径を一定にするため
の焦点制御信号検出装置に関する。DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a focus control signal detection device for making the irradiation spot diameter of a light beam irradiated onto an information medium constant in an optical information recording and reproducing device.
従来よゆ、この種の装置には種々の型式のものがある。Conventionally, there are various types of devices of this type.
その中で情報媒体からの反射ビームを光検出素子に照射
させ、情報媒体と収束レンズとの間隙ずれ、即ち情報媒
体に対する光ビームの照射スポット径の変化に対応して
、光検出素子上での反射ビームの照射スポット径が変化
し、光検出素子の受光量も変化することを利用し、この
受光量の変化を光ビームの焦点制御信号として検出する
ものがある。この場合、単に情報媒体と収束レン媒体の
部分的な反射率の変化、あるいは光ビームを発する光源
自体の発生光量の変化によって、光検出素子が受ける反
射ビームの光ｌ゛も変化することに力均、必ずしも光検
出素子の受光量の変化と前述の間隙ずれとが一致しない
と云う欠点がある。In this process, the reflected beam from the information medium is irradiated onto the photodetecting element, and the light beam on the photodetecting element is adjusted in response to the gap deviation between the information medium and the converging lens, that is, the change in the diameter of the irradiation spot of the light beam on the information medium. Some devices utilize the fact that the irradiation spot diameter of the reflected beam changes and the amount of light received by the photodetector element also changes, and detect this change in the amount of light received as a focus control signal of the light beam. In this case, it is possible that the light l of the reflected beam received by the photodetector will also change simply due to a change in the partial reflectance of the information medium and the converging lens medium or a change in the amount of light generated by the light source itself that emits the light beam. However, there is a drawback that the change in the amount of light received by the photodetecting element does not necessarily match the gap deviation described above.
そこで、公知のように、光検出素子を４つの受光素子よ
り構成し、反射ビームが光検出素子に入射する前にシリ
ンドリカルレンズを配し、このしンズの非点収差を利用
して、前述の間隙ずれを検出するものがある。しかしこ
の場合、特殊なシリンドリカルレンズを装置に組込１ね
ばなら力いと云う欠点がある。Therefore, as is well known, the photodetecting element is composed of four photodetecting elements, and a cylindrical lens is placed before the reflected beam enters the photodetecting element, and the astigmatism of this lens is utilized to There are devices that detect gap misalignment. However, in this case, there is a disadvantage in that a special cylindrical lens must be incorporated into the device.
本発明は上記の点に鑑みて、きわめて容易に、しかも正
確に情報媒体を収束レンズとの間隙ずれを検出できるよ
うにすることを目的とする。In view of the above points, it is an object of the present invention to make it possible to detect the gap deviation between the information medium and the converging lens very easily and accurately.
以下本発明の一実施例を図面に従い説明する。An embodiment of the present invention will be described below with reference to the drawings.
光源１から発する光ビーム２は、レンズ８、偏光ビーム
スプリッタ４．４分の１波長板５及び収束レンズ６を透
過し、この収束レンズ６にて、光ビーム２を公知のよう
に情報トラック７を形成した情報媒体８上に照射スポッ
ト９として照射する。A light beam 2 emitted from a light source 1 passes through a lens 8, a polarizing beam splitter 4, a quarter wavelength plate 5, and a converging lens 6. The converging lens 6 converts the light beam 2 into an information track 7 in a known manner. An irradiation spot 9 is irradiated onto the information medium 8 on which the irradiation light has been formed.
情報媒体８を照射した反射ビーム１０は、再び収壺
束レンズ６．４分の１波長板を透過し、前記偏光ビーム
スプリッタ４にて光検出素子１１にレンズ１２を介して
入射する。光検出素子１１は４つの受光素子１１ａ、１
ｌｂｓ １１０，１１（ｌより構成され、これらの受光
素子より、受光素子１１ａとｌｌｂとのＡ群、受光素子
１１ｃと１１（ｌとのＢ群、受光素子１１ａとｌｌｃと
の０群、受光素子１１ｂと１１（１とのＤ群との各々の
群に分ける。The reflected beam 10 that has irradiated the information medium 8 passes through the converging lens 6 and the quarter-wave plate again, and enters the photodetecting element 11 via the lens 12 at the polarizing beam splitter 4 . The photodetecting element 11 includes four light receiving elements 11a, 1
lbs 110, 11 (l), and from these light receiving elements, a group A of light receiving elements 11a and llb, a group B of light receiving elements 11c and 11(l), a group 0 of light receiving elements 11a and llc, a group 0 of light receiving elements 11a and llc, and a group of light receiving elements 11a and llb. D group: 11b and 11(1).
そして前記Ａ群とＢ群との接合部１２を、前記情射スポ
ット１８の径の中心を前記接合部１２よりずらせている
。このため、前記情報トラック７に対する光ビーム２の
照射スポット９の位置ずれは、この位置ずれによね、照
射スポット９が位置する情報トラック７のピッ）？ａと
それ以外の部分とで生じる反射部分の割合が適正位置に
照射スポット９が位置する時に比べ変るため、受光素子
Ｃ群とＤ群との受光量差に変化が生じ、この変化にて位
置ずれの程度をトラッキング信号として検出できる。ま
た情報媒体８に対する光ビーム２の照射スポット９の焦
点制御は、情報媒体８に対する収束レンズ６０間隙すれ
として考えられ、第５図の如く・１．前記反射ビームｌ
Ｏの光検出素子１１上での照射スポット１Ｂの径が変化
することで判断できる。そこで本発明では、照射スポッ
ト９が情報媒体８に対して適正焦点である時の照射スポ
ット１８の径と位置を基準とし、照射スポットの径の群
の出力の増巾率より小さくする。従って、光ビーム２の
照射スポット９の情報媒体８に対する焦点ずれは、受光
素子Ａ群とＢ群との受光量差が焦点制御信号となる。更
に、光検出素子１１全体の受光量の変化は、情報トラッ
ク７として形成した各ビットの変化を受け、これから情
報再生信号を得る。そして光ビーム２が情報媒体８へ照
射した後の反射ビーム１０の全体が照射スポット１８と
して光検出素子１１に入射されるため、情報媒体８のビ
ット７ａとして形成した部分と、その他の部分との区別
が、受光量の差として明確にあられれるため、情報再生
も確実に行なわれる。The center of the diameter of the incident spot 18 is shifted from the joining part 12 between the A group and the B group. Therefore, the positional deviation of the irradiation spot 9 of the light beam 2 with respect to the information track 7 is caused by the positional deviation of the information track 7 on which the irradiation spot 9 is located. Since the ratio of the reflected area generated between a and other areas changes compared to when the irradiation spot 9 is located at the proper position, a change occurs in the difference in the amount of light received between the light receiving elements C group and D group, and this change causes a change in the position The degree of deviation can be detected as a tracking signal. Further, the focus control of the irradiation spot 9 of the light beam 2 on the information medium 8 can be considered as a gap between the converging lens 60 and the information medium 8, as shown in FIG. The reflected beam l
This can be determined by the change in the diameter of the irradiation spot 1B on the photodetector element 11 of O. Therefore, in the present invention, the diameter and position of the irradiation spot 18 when the irradiation spot 9 is properly focused with respect to the information medium 8 are used as a reference, and the amplification rate of the output of the group is set to be smaller than the diameter of the irradiation spot. Therefore, for the focal shift of the irradiation spot 9 of the light beam 2 with respect to the information medium 8, the difference in the amount of light received between the light receiving element groups A and B serves as a focus control signal. Further, changes in the amount of light received by the entire photodetector element 11 are affected by changes in each bit formed as an information track 7, and an information reproduction signal is obtained from this change. Since the entire reflected beam 10 after the light beam 2 irradiates the information medium 8 is incident on the photodetector element 11 as the irradiation spot 18, the part formed as the bit 7a of the information medium 8 and the other parts are different from each other. Since the distinction can be clearly seen as a difference in the amount of light received, information can be reproduced reliably.
上記実施例では４つの受光素子を使用して光検出素子を
説明したが、焦点制御のみを考えれば、受光素子は２つ
でよい。In the above embodiment, the photodetecting element was explained using four light receiving elements, but if only focus control is considered, only two light receiving elements are required.
本発明は上記の如く構成したために、特殊な部品、装置
を使用することなく、容易に、しかも確実に情報媒体と
収束レンズとの間隙ずれ、即ち情報媒体に対する光ビー
ムの照射径を適正に制御する制御信号を検出できるもの
である。Since the present invention is configured as described above, the gap deviation between the information medium and the converging lens, that is, the irradiation diameter of the light beam on the information medium can be easily and reliably controlled without using any special parts or equipment. The control signal can be detected.
第１図は情報媒体の一部拡大図、第２図は本発明の光学
系を示す説明図、第８図は光検出素子の上面図、第４図
は光検出素子と情報トラックとの光学的関係を示す図、
第５図は光検出素子と反射ビームの照射スポットとの関
係を示す図である。
２・・光ビーム、６・・収束レンズ、８・・情報媒体、
１０・−反射ビーム、１１・・光検出素子、１ｌａｓ
ｌｌ’ｂ％１１ｃ％ １１（１１１１１光電素子、１２
・・接合部、１８・・反射ビームの照射スポット。
特許出願人 萬世工業株式会社
６−Fig. 1 is a partially enlarged view of the information medium, Fig. 2 is an explanatory diagram showing the optical system of the present invention, Fig. 8 is a top view of the photodetecting element, and Fig. 4 is an optical diagram of the photodetecting element and the information track. A diagram showing the relationship between
FIG. 5 is a diagram showing the relationship between the photodetecting element and the irradiation spot of the reflected beam. 2. Light beam, 6. Converging lens, 8. Information medium,
10.-Reflected beam, 11.. Photodetection element, 1las
ll'b%11c% 11 (11111 photoelectric element, 12
...Joint part, 18...Irradiation spot of reflected beam. Patent applicant: Mansei Kogyo Co., Ltd. 6-
Claims (1)
、情報媒体からの反射ビームを少なくとも２つの光電素
子よりなる光検出素子に照射し、前記情報媒体と収束レ
ンズとの間隙ずれ信号を、前記光電素子の受光量の差の
変化として検出してなる焦点制御信号検出装置において
、前記反射ビームの光検出素子上での照射スポット径の
中心を前記光電素子の接合部よりずらせ、前記光電素子
の内、ずらせたことにより受光量の大きくなった光電素
子の出力の増巾率を、他の光電素子の出力の増巾率より
小さくしてなる光学的情報記録、再生装置における焦点
制御信号検出装置。1. Irradiating the information medium with a light beam through a converging lens, irradiating the reflected beam from the information medium onto a photodetecting element consisting of at least two photoelectric elements, and detecting a gap deviation signal between the information medium and the converging lens, In the focus control signal detection device that detects a change in the amount of light received by the photoelectric element, the center of the diameter of the irradiation spot of the reflected beam on the photodetection element is shifted from the junction of the photoelectric element, Focus control signal detection in optical information recording and reproducing devices in which the amplification rate of the output of the photoelectric element that receives a large amount of light due to the shift is made smaller than the amplification rate of the output of other photoelectric elements. Device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10176781A JPS583140A (en) | 1981-06-30 | 1981-06-30 | Focus controlling signal detector in optical information recorder and reproducer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10176781A JPS583140A (en) | 1981-06-30 | 1981-06-30 | Focus controlling signal detector in optical information recorder and reproducer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS583140A true JPS583140A (en) | 1983-01-08 |
Family
ID=14309368
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP10176781A Pending JPS583140A (en) | 1981-06-30 | 1981-06-30 | Focus controlling signal detector in optical information recorder and reproducer |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS583140A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0189933A2 (en) * | 1985-01-31 | 1986-08-06 | Fujitsu Limited | Servo system of storage apparatus for controllably projecting an optical beam to an optical disk |
-
1981
- 1981-06-30 JP JP10176781A patent/JPS583140A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0189933A2 (en) * | 1985-01-31 | 1986-08-06 | Fujitsu Limited | Servo system of storage apparatus for controllably projecting an optical beam to an optical disk |
| US4888752A (en) * | 1985-01-31 | 1989-12-19 | Fujitsu Limited | Focusing and tracking servo system for controlling the projection of an optical beam on an optical disk |
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