JPS5737751A - Optical reader - Google Patents
Optical readerInfo
- Publication number
- JPS5737751A JPS5737751A JP11446980A JP11446980A JPS5737751A JP S5737751 A JPS5737751 A JP S5737751A JP 11446980 A JP11446980 A JP 11446980A JP 11446980 A JP11446980 A JP 11446980A JP S5737751 A JPS5737751 A JP S5737751A
- Authority
- JP
- Japan
- Prior art keywords
- transmitted
- refracted
- light
- truncated
- critical angle
- 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
- 230000003287 optical effect Effects 0.000 title abstract 4
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
PURPOSE:To obtain a focus error signal by providing a truncated conical optical element on the light emission side of a polarizing prism which reflects reflected light from a disk, and by detecting variations in the quantities of reflected light and transmitted light on the slanting surface of the optical element. CONSTITUTION:On the light emission side of a polarizing prism 3, an optical detecting element 30 having a slanting surface 30a set nearly at a critical angle to an incident light beam in a focusing state is provided. In the focusing state, the beam is totally reflected by the slanting surface 30a to be transmitted in the element by being refracted by the truncated surface 30b and when a disk 6 shifts as shown by an arrow (a), it is incident at an angle less than the critical angle to be separated into a reflected part and a refracted and transmitted part while a (b) directional shif increases an incidence angle greater above the critical angle to cause total reflection, so that it is refracted by the truncated surface 30b and transmitted. Photodetecting elements 32A-32C are provided opposing to the truncated surface 30b to obtain a focus error signal by using the difference between the sum of the outputs of the 32A and 30B, and that of the 32C.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11446980A JPS5737751A (en) | 1980-08-19 | 1980-08-19 | Optical reader |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11446980A JPS5737751A (en) | 1980-08-19 | 1980-08-19 | Optical reader |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS5737751A true JPS5737751A (en) | 1982-03-02 |
Family
ID=14638506
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP11446980A Pending JPS5737751A (en) | 1980-08-19 | 1980-08-19 | Optical reader |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5737751A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6288068U (en) * | 1985-11-21 | 1987-06-05 |
-
1980
- 1980-08-19 JP JP11446980A patent/JPS5737751A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6288068U (en) * | 1985-11-21 | 1987-06-05 |
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