Catadioptric reduction lens
US6765729B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 23, 2002 |
| Grant date | Jul 20, 2004 |
| Priority date | — |
| Expiry date | Jan 23, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70225
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A catadioptric projection lens for projecting a pattern located in an object plane onto an image plane without an intermediate image includes the following components between the object plane and the image plane in the given order: a first lens part for creating a beam that is directed at a physical beam splitter, a physical beam splitter with a beam splitter surface, a mirror group with a concave mirror, and a second lens part with positive focal power to create an image of the pattern on the image plane. The mirror group preferably has no free-standing lens, and the focal power of the mirror group is largely determined by the magnification of the concave mirror. The focal power of the mirror group is large enough to convert the incident divergent beam into a convergent beam. The system aperture is located on the image side behind of the concave mirror, preferably at the exit of the beam splitter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.