Lens system with lens elements arranged in a gas-filled holder and photolithographic apparatus including such a system
US5602683A · kind A · utility
36Cited by
7References
4Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 21, 1994 |
| Grant date | Feb 11, 1997 |
| Priority date | — |
| Expiry date | Dec 21, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70933
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A high-quality lens system (PL) is described, which system is rinsed with a gas having a low refractive index so as to reduce the influence of variations of ambient parameters on the optical behaviour. By adding a very small quantity of ozone to this gas, it is prevented that any deposit will be produced on the lens elements within the lens holder (PLH) as a result of decomposition of organic particles caused by UV radiation and precipitation of the decomposition products.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.