Hollow lightpipe using a low refractive index inner layer
US4805987A · kind A · utility
Inventors
Key dates
| Filing date | Dec 29, 1987 |
| Grant date | Feb 21, 1989 |
| Priority date | — |
| Expiry date | Dec 29, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B6/032
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A hollow lightpipe for conducting high power levels of CO.sub.2 laser light with low transmission losses. A highly reflective layer is formed on the inner surface of an elongated bendable metal housing. The material forming the highly reflective layer is chosen to have a complex index of refraction whose real part (n) is less than about 0.4. The thickness of the reflective layer need not be highly controlled, but must be sufficiently thick that it exhibits bulk absorption properties without being so thick that it cracks when the lightpipe is flexed. In a second embodiment, the transmission properties of the highly reflective layer can be enhanced by coating the reflective layer with a thin film of a dielectric materials such as ThF.sub.4 and Ge.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.