Liquid crystal light valve projector with improved contrast ratio and with 0.27 wavelength compensation for birefringence in the liquid crystal light valve
US5576854A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 12, 1993 |
| Grant date | Nov 19, 1996 |
| Priority date | — |
| Expiry date | Nov 12, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/133638
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
In a liquid crystal light valve projector, a quarter-wave compensator plate is disposed between a polarization plate and a liquid crystal light valve to compensate for polarization irregularities induced by the off-incident reflections in the cone of light projected onto the LCLV. The quarter-wave compensation plate reverses the phase of the P component of said illumination light with respect to said compensator plate by 180.degree. thereby eliminating P-polarization leakage during the dark state of an LCLV projector. The invention also combines the compensator plate with a heat shield and a low stress-optical coefficient counter electrode substrate to reduce the birefringence of the LCLV thereby also minimizing leakage of P-polarized light onto the projection screen during the dark state of the projector.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.