Optical window purge arrangement
US4521089A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 17, 1983 |
| Grant date | Jun 4, 1985 |
| Priority date | — |
| Expiry date | Oct 17, 2003 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B27/0006
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An arrangement for isolating an optical surface from a contaminating environment utilizes concentric inner and outer tubes defining an annular purging space therebetween. The inner and outer tubes are both open ended with the open ends facing the contaminating environment. The optical surface is positioned in the inner tube and is spaced from the open end of the inner tube. The inner tube is made of porous material and the space is supplied with a purging gas so that at least some of the purging gas filters into an inner space of the inner tube to prevent an aspiration of contaminants into the inner tube from the open end thereof. A preferred porosity range of 1 to 40 microns is selected for the inner tube which preferably has a length to diameter ratio of from about 5 to 1.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.