Oblique projection optical system and method for setting the same
US6822811B2 · kind B2 · utility
2Cited by
11References
13Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Mar 21, 2003 |
| Grant date | Nov 23, 2004 |
| Priority date | — |
| Expiry date | May 1, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B17/0663
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An oblique projection optical system is compact as compared with the size of the image it presents, offers high imaging performance, produces satisfactorily small distortion, and has a small f-number. The oblique projection optical system is composed of a plurality of powered reflection surfaces, of which the one closest to the projection surface is positively powered and the one second closest thereto is negatively powered. At least one of these two reflection surfaces is a free-form surface, and the one closest to the projection surface has a size larger than half the size of the projection surface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.