Optical imaging system provided with an opto-electronic detection system for determining a deviation between the image plane of the imaging system and a second plane on which an image is to be formed
US4356392A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 11, 1980 |
| Grant date | Oct 26, 1982 |
| Priority date | — |
| Expiry date | Jun 11, 2000 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70825
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An optical imaging system is described which is provided with an opto-electronic detection system for determining a deviation between the image plane of the imaging system and a second plane on which an image is to be formed by the imaging system. After a first reflection on the second plane an auxiliary beam which is obliquely incident on said plane is reflected along itself and mirror-inverted, is subsequently reflected a second time on the second plane, and is finally incident on two detectors. The difference signal of the detectors, which is a measure of the deviation, is unaffected by tilting of the second plane and by local variations in reflectivity of in said plane.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.