Apparatus for reading an optical radiation-reflecting information carrier for controlling focus
US4270045A · kind A · utility
2Cited by
4References
6Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Sep 19, 1977 |
| Grant date | May 26, 1981 |
| Priority date | — |
| Expiry date | Sep 19, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/0924
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An apparatus as described for reading an optical radiation-reflecting information carrier, which apparatus comprises an opto-electronic focussing error detection system with two focussing detectors. The path of the read beam which has been reflected by the information carrier and which originates from the read spot includes a single radiation-deflecting element, in such a way that the radiation which is incident on this element is deflected towards the focussing detectors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.