Method and apparatus to achieve a neutral dark state in image projection systems
US7390094B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 15, 2005 |
| Grant date | Jun 24, 2008 |
| Priority date | — |
| Expiry date | Feb 7, 2026 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B21/28
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An absorptive layer is added to an image display system. The absorptive layer is selected to compensate for tint in a black state of a displayed image. In a Liquid Crystal On Silicon (LCOS) based light engine, blue wavelengths may cause a predominate tint in black portions of an image (or an entirely black image is tinted blue), and the absorptive layer is calculated to absorb an amount of blue equivalent to the tint. The absorptive layer is, for example, an unbalanced magenta dichroic, or a yellow filter. The yellow filter may be placed at any point in the light chain, including input/output of a kernel, input/output of a projection lens, or portions of a light engine or display screen. An unbalanced magenta may be constructed by adding a yellow filter to an existing magenta dichroic in the kernel design.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.