Optical read-out system including asymetrical beam intensity and four detector cells
US4059841A · kind A · utility
70Cited by
11References
22Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Sep 24, 1976 |
| Grant date | Nov 22, 1977 |
| Priority date | — |
| Expiry date | Sep 24, 1996 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/12
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The invention relates to the optical reading of a support comprising a track along which is arranged a series of information items which optically translate a carrier wave angularly modulated by the information. The read-out system uses a single lens for projecting a quasi-punctiform spot onto the support; a photodetector comprising four cells arranged in a square and asymmetrical illumination of the lens to ensure detection of the information and simultaneous supply of defocussing and tracking deviation signals.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.