Electrically addressable liquid crystal projection system with high efficiency and light output
US5115305A · kind A · utility
Inventors
Key dates
| Filing date | Jul 5, 1990 |
| Grant date | May 19, 1992 |
| Priority date | — |
| Expiry date | Jul 5, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/3105
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An improved polarized color video projector incorporates a light source to provide three collimated beams of linearly polarized light of blue, green, and red colors. A light modulator capable of imparting a video image in a light beam is positioned in each of the three colored beams to modulate the individual colored image components in each of the beams. A dischroic beam recombiner receives the modulated blue and green beams, and recombines them into a combined blue and green color image carrying beam. A polarization-selective/beam analyzer/recombiner receives the recombined blue and green beam and recombines it with the red beam. A retarder placed between the light modulator for the red beam and the polarization-selective/beam analyzer/recombiner, in the path of the modulated red beam, rotates the plane of polarization of the red beam to allow it to be recombined with the recombined blue and green beam in the polarization-selective/beam analyzer/recombiner. Projection apparatus receives the recombined blue, green, and red beams and projects them onto a display screen.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.