Variable vergency focussing apparatus
US4124273A · kind A · utility
30Cited by
4References
9Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Oct 22, 1976 |
| Grant date | Nov 7, 1978 |
| Priority date | — |
| Expiry date | Oct 22, 1996 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0908
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The invention relates to variable vergency focussing systems which enable the focussing of a light beam on an object to be maintained despite movements of the object. The invention consists in using as variable-vergency element two astigmatic elements made of electro-optical material which are arranged at 90.degree. relative to one another and are subjected to voltages variable in dependence upon the vergency to be obtained.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.