Liquid crystal achromatic compound retarder
US5658490A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 7, 1995 |
| Grant date | Aug 19, 1997 |
| Priority date | — |
| Expiry date | Apr 7, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F2413/02
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
This invention provides achromatic liquid crystal compound retarders, achromatic polarization switches, and achromatic shutters using the liquid crystal compound retarders. It further provides achromatic variable retardance smectic liquid crystal retarders. The compound retarder of this invention comprises a central liquid crystal retarder unit and two external passive retarders positioned in series with and on either side of the liquid crystal retarder unit. The liquid crystal retarder unit comprises either (1) a rotatable smectic liquid crystal half-wave retarder or (2) first and second liquid crystal variable retarders having retardance switchable between zero and half-wave. The external passive retarders are equal in retardance and orientation to each other. Design equations determine the retardance of the external elements and their orientation relative to the central retarder to obtain a particular achromatic retardance for the compound structure.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.