Method and apparatus for unobstructed telescopic communications
US6674576B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 3, 2001 |
| Grant date | Jan 6, 2004 |
| Priority date | — |
| Expiry date | Nov 22, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B27/28
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Use of a filter in lieu of a secondary reflector in a reflective telescope provides compact design that eliminates the obstruction caused by the secondary reflector. The filter is selectively reflective to either the angle of incidence of radiation striking the filter or to the polarization exhibited by the radiation. An angularly sensitive filter may be constructed to either a bandpass filter or a short pass filter. A filter that is sensitive to polarization is constructed from a cholesteric liquid crystal. The filter is disposed in front of a primary reflector that comprises an aperture for collecting radiation observed by the telescope.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.