JPS63157818U - - Google Patents
Info
- Publication number
- JPS63157818U JPS63157818U JP1987049615U JP4961587U JPS63157818U JP S63157818 U JPS63157818 U JP S63157818U JP 1987049615 U JP1987049615 U JP 1987049615U JP 4961587 U JP4961587 U JP 4961587U JP S63157818 U JPS63157818 U JP S63157818U
- Authority
- JP
- Japan
- Prior art keywords
- magneto
- incident
- optical
- linearly polarized
- focus error
- 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
- 239000000758 substrate Substances 0.000 claims description 3
- 238000001514 detection method Methods 0.000 claims 2
- 230000003287 optical effect Effects 0.000 claims 2
- 230000010287 polarization Effects 0.000 claims 1
- 238000010586 diagram Methods 0.000 description 5
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
Description
第１図は本考案の実施例のλ／２板の一例の平
面図、第２図は光検出器上のビームスポツトの光
強度分布を示す図、第３図は実施例のλ／２板の
他の例を示す平面図、第４図は参考例の光検出器
の配置図、第５図はシリンドリカルレンズの配置
の説明図、第６図は従来例の配置図、第７図は光
検出器上のビームスポツトの光強度分布を示す図
、第８図は従来例のλ／２板の配置図である。
１はレーザダイオード、２はコリメータレンズ
、３はビームスプリツタ、４は対物レンズ、５は
光磁気デイスク、６は透明基板、７は磁性層、８
，８′はλ／２板、８Ａ′，８Ｂ′；８ａ′〜８
ｄ′はλ／２板部である。
Fig. 1 is a plan view of an example of a λ/2 plate according to an embodiment of the present invention, Fig. 2 is a diagram showing the light intensity distribution of a beam spot on a photodetector, and Fig. 3 is a plan view of an example of a λ/2 plate according to an embodiment of the present invention. FIG. 4 is a plan view showing another example of the photodetector, FIG. 5 is an explanatory diagram of the arrangement of the cylindrical lens, FIG. 6 is a layout diagram of the conventional example, and FIG. FIG. 8, which is a diagram showing the light intensity distribution of the beam spot on the detector, is a layout diagram of a conventional λ/2 plate. 1 is a laser diode, 2 is a collimator lens, 3 is a beam splitter, 4 is an objective lens, 5 is a magneto-optical disk, 6 is a transparent substrate, 7 is a magnetic layer, 8
, 8' are λ/2 plates, 8A', 8B';8a' to 8
d' is a λ/2 plate portion.
Claims (1)
用い、直線偏光の集束ビームを上記光磁気媒体の
透明基板を透過して磁性層に入射せしめ、その出
射ビームを集束させてシリンドリカルレンズを透
過して検光子に入射せしめ、該検光子から得られ
た直線偏光ビームを光検出器に入射せしめ、該光
検出器から非点収差方式のフオーカスエラー信号
を得るようにした光磁気ヘツドのフオーカスエラ
ー検出装置において、 入射直線偏光の偏光面に対し、夫々 ２２．５°±９０°×ｎ −２２．５°±９０°×ｎ （但し、ｎ＝０，１，２，３，……） の方向に光学軸を有し、その入射偏光面と平行又
は垂直な方向に沿つて分割された対をなす１／２
波長板部から成る１／２波長板を、上記シリンド
リカルレンズの入射光路に配して成る光磁気ヘツ
ドのフオーカスエラー検出装置。[Claims for Utility Model Registration] Using a magneto-optical medium in which a magnetic layer is formed on a transparent substrate, a focused beam of linearly polarized light is transmitted through the transparent substrate of the magneto-optical medium and incident on the magnetic layer, and the output beam is The linearly polarized beam obtained from the analyzer is made incident on a photodetector, and an astigmatic focus error signal is obtained from the photodetector. In the focus error detection device for a magneto-optical head, the polarization plane of the incident linearly polarized light is 22.5°±90°×n −22.5°±90°×n (however, n=0, 1, 2, 3, ...) with an optical axis in the direction of
A focus error detection device for a magneto-optical head, comprising a 1/2 wavelength plate consisting of a wavelength plate section arranged in the incident optical path of the cylindrical lens.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1987049615U JPH075549Y2 (en) | 1987-03-31 | 1987-03-31 | Magneto-optical head focus error detector |
| KR1019880003469A KR880011751A (en) | 1987-03-31 | 1988-03-30 | Focus error detection device of magneto-optical head |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1987049615U JPH075549Y2 (en) | 1987-03-31 | 1987-03-31 | Magneto-optical head focus error detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63157818U true JPS63157818U (en) | 1988-10-17 |
| JPH075549Y2 JPH075549Y2 (en) | 1995-02-08 |
Family
ID=30872231
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1987049615U Expired - Lifetime JPH075549Y2 (en) | 1987-03-31 | 1987-03-31 | Magneto-optical head focus error detector |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPH075549Y2 (en) |
| KR (1) | KR880011751A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04177623A (en) * | 1990-11-09 | 1992-06-24 | Nec Corp | Optical information recording/reproducing apparatus |
| JPH04205731A (en) * | 1990-11-29 | 1992-07-27 | Nec Corp | Optical head device |
-
1987
- 1987-03-31 JP JP1987049615U patent/JPH075549Y2/en not_active Expired - Lifetime
-
1988
- 1988-03-30 KR KR1019880003469A patent/KR880011751A/en not_active Application Discontinuation
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04177623A (en) * | 1990-11-09 | 1992-06-24 | Nec Corp | Optical information recording/reproducing apparatus |
| JPH04205731A (en) * | 1990-11-29 | 1992-07-27 | Nec Corp | Optical head device |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH075549Y2 (en) | 1995-02-08 |
| KR880011751A (en) | 1988-10-31 |
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