JPS5661043A - Detector for focus - Google Patents
Detector for focusInfo
- Publication number
- JPS5661043A JPS5661043A JP13644479A JP13644479A JPS5661043A JP S5661043 A JPS5661043 A JP S5661043A JP 13644479 A JP13644479 A JP 13644479A JP 13644479 A JP13644479 A JP 13644479A JP S5661043 A JPS5661043 A JP S5661043A
- Authority
- JP
- Japan
- Prior art keywords
- light
- incident
- prisms
- location
- prism
- 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
- Optical Recording Or Reproduction (AREA)
- Automatic Focus Adjustment (AREA)
Abstract
PURPOSE:To simplify the constitution and to make small and light the device with less number of optical elements, by using a plurality of prisms consisting of plural refractive materials as optical path split prisms so that the incident and reflected light flux pass through the same optical elements. CONSTITUTION:The light from a light source 21 is made to a parallel light flux at a collimator lens 22, and it is incident to plural prisms, e.g., a Rochon prism 23. This light is the P polarized light component being normal light to the Rochon prism 23, it passes through along the light axis O and is incident to the information track of a recording medium 26 via a 1/4 wave length plate 24 and an objective lens 25. The light reflected at it is converted for the direction of polarization from P into S component at the 1/4 wave length plate 24. Accordingly, it is refracted at the Ronchon prism 23 and incident with a slope to the light axis O of the collimator lens 22 to form an image of photospot at a location different from the location of the light source 21. A four-split photodetector 27 is located at this location to obtain a focus error signal.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP13644479A JPS5661043A (en) | 1979-10-24 | 1979-10-24 | Detector for focus |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP13644479A JPS5661043A (en) | 1979-10-24 | 1979-10-24 | Detector for focus |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS5661043A true JPS5661043A (en) | 1981-05-26 |
Family
ID=15175250
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP13644479A Pending JPS5661043A (en) | 1979-10-24 | 1979-10-24 | Detector for focus |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS5661043A (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5868246A (en) * | 1981-10-19 | 1983-04-23 | Hitachi Ltd | Focus error detector |
JPH07262600A (en) * | 1995-02-27 | 1995-10-13 | Canon Inc | Optical head device |
US5870370A (en) * | 1993-09-24 | 1999-02-09 | Ricoh Company, Ltd. | Optical pickup apparatus |
JP2010147481A (en) * | 1998-03-30 | 2010-07-01 | Toshiba Corp | Noise reducing element, and semiconductor circuit element using the same |
-
1979
- 1979-10-24 JP JP13644479A patent/JPS5661043A/en active Pending
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5868246A (en) * | 1981-10-19 | 1983-04-23 | Hitachi Ltd | Focus error detector |
US5870370A (en) * | 1993-09-24 | 1999-02-09 | Ricoh Company, Ltd. | Optical pickup apparatus |
USRE40414E1 (en) * | 1993-09-24 | 2008-07-01 | Ricoh Company, Ltd. | Optical pickup apparatus |
JPH07262600A (en) * | 1995-02-27 | 1995-10-13 | Canon Inc | Optical head device |
JP2010147481A (en) * | 1998-03-30 | 2010-07-01 | Toshiba Corp | Noise reducing element, and semiconductor circuit element using the same |
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