High resolution reduction catadioptric relay lens
US5241423A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 1, 1991 |
| Grant date | Aug 31, 1993 |
| Priority date | — |
| Expiry date | Aug 1, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70791
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An optical system of a NX reduction catadioptric relay lens having sub-half micron resolution over the ultraviolet band width is described. A spherical mirror with a stop at the mirror is used to work at substantially the desired reduction ratio and the desired high numerical aperture sufficient to provide the desired high resolution. A beam splitting cube with appropriate coatings is used to form an accessible image of an object on an image plane. Refracting correctors in the path of the slow beam incident on the mirror and in the path of the fast beam reflected on the mirror are designed to fix the aberrations of the image formed by the mirror. The beam splitter coatings are chosen in such a way that beams reflected from and transmitted therethrough suffer no net aberration as a result of multiple reflections within the thin film beam splitter coatings and therefore are substantially free of aberration, distortion and apodization which would result from the beam splitting surface in the absence of these coatings.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.