Optical illumination device
US5906429A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 25, 1997 |
| Grant date | May 25, 1999 |
| Priority date | — |
| Expiry date | Jul 25, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70916
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An optical illumination device reflects and condenses light from a mercury-arc lamp by a light reflecting and condensing member and then reflects and deflects the light, thereafter the reflected and deflected light is transferred to a relay-lens system through a collimator lens or input lens, band-pass filter and fly-eye lens. Gas from which impurities are removed by a filter is flown around optical elements to separate the optical elements from air containing material causing clouding of the optical elements to thereby restrain clouding of the optical elements. On the other hand, or in addition, the reflectance of the light reflecting and condensing member and/or miller for the light of the absorption band of sulfur dioxide is made small to prevent the optical elements from clouding.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.