High performance projection display with two light valves
US5517340A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 30, 1995 |
| Grant date | May 14, 1996 |
| Priority date | — |
| Expiry date | Jan 30, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/133622
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A simplified two-light valve configuration for high performance projection displays which eliminates much complexity and the costs associated with three-light valve projection displays, such as a crossed dichroic beam splitter cube, a long retrofocus projections lens, and the additional cost and complexity of a third light valve. Two reflective liquid crystal light valves are positioned and aligned relative to each other on two adjacent surfaces of a polarizing beam splitter cube. Illumination is introduced through a third face of the cube, and a projection lens images the two light valves through a fourth surface of the polarizing beam splitter cube. Color-sequential and alternating polarization states are provided by a color filter wheel or cage containing individual facets of dichroic or color glass filters, such that as the wheel or cage rotates, the filters change and produce sequential red, green and blue outputs. In addition, the polarization of adjacent colors is alternated by adding a polarizing film onto each color filter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.