Split-element liquid crystal tunable optical filter
US5528393A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 12, 1994 |
| Grant date | Jun 18, 1996 |
| Priority date | — |
| Expiry date | Jul 12, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F2203/50
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
This invention provides split-element liquid crystal polarization interference filters in wide-field, bandpass, cut-on, cut-off and notch filter embodiments. The split-element filters of this invention comprise a polarization interference stage defined by a pair of polarizers. Disposed within the stage are a center retarder, and first and a second split-element retarder, the split-element retarders having equal retardances and positioned in series with and on either side of the center retarder. The retarders can be liquid crystal variable retarders or can be fixed retarders used in combination with liquid crystal retarders. Double split-element filters in passive and tunable embodiments are provided comprising, within a polarization interference stage, a center retarder, an inside pair of split-element retarders and an outside pair of split-element retarders.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.