Opto-electronic focus detection system
US3969575A · kind A · utility
24Cited by
3References
6Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 6, 1974 |
| Grant date | Jul 13, 1976 |
| Priority date | — |
| Expiry date | Dec 6, 1994 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2007/0924
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In an opto-electronic focus detection system for determining a deviation between the plane of focussing of an objective and a radiation-reflecting surface the path of a focussing beam which is reflected by said surface includes an assembly of two radiation-sensitive detection elements. The difference in the output signals of said elements is proportional to said deviation. By disposing a lenslike element of which only the outer zone has a lens action before the detection elements, the measuring range can be extended while maintaining the sensitivity for small deviations.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.