High contrast polarizing optics for a color electro-optic display device
US6563551B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 28, 2000 |
| Grant date | May 13, 2003 |
| Priority date | — |
| Expiry date | Oct 17, 2021 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/7441
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A projection-type color image display system uses a reflective liquid crystal (LC) light modulator (24) and a polarizing beam-splitter (22) for separating the incoming and reflected light. Light from the source arrives on a first axis (28) and is reflected outward, with the imposed image, along a second axis (30) through a projection lens (26). In order to produce a high contrast image, a pre-polarizer (36, 42, 48) and/or post-polarizer (44, 50) are used to restore the selectivity and, consequently, optical system contrast for the wide “cone of acceptance” of light rays which are common in projection systems. In order to improve the system contrast, the pre- and/or post-polarizer is arranged along the first and second axis, respectively, with its polarizer absorbing axis extending parallel to the normal n of the reflective surface (34, 46) of the PBS.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.