Circularly polarized light source
US4073571A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 5, 1976 |
| Grant date | Feb 14, 1978 |
| Priority date | — |
| Expiry date | May 5, 1996 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B5/3016
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
There is disclosed a circularly polarized light source including a circular light polarizer using cholesteric liquid crystal material in an arrangement such that substantially 100% of the unpolarized light input may be utilized in a circularly polarized output in either a narrow band or wide band configuration. The circular polarizer itself comprises one or a plurality of liquid crystal cells having liquid crystal material of a predetermined ratio by weight of cholesteric to nematic liquid crystal type in each cell. The ratio of the types of materials determines a central wavelength to which each cell is tuned in its polarizing action. If a single cell is used, light of a predetermined bandwidth around its central wavelength is polarized. If a plurality of cells are stacked in a sandwich arrangement wherein each cell is tuned to a different wavelength selected in such a sequentially stepped fashion that the bandwidths for the cells form a continuous spectrum, then there is formed a wideband polarizer which can readily encompass the entire visible wavelength region of the spectrum.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.