Method and apparatus to increase the contrast ratio of the image produced by a LCoS based light engine
US7175281B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | May 12, 2004 |
| Grant date | Feb 13, 2007 |
| Priority date | — |
| Expiry date | Sep 14, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G2320/0673
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A transmissive LCD is placed in optical series with pixels of an image. The transmissive LCD is set to full transmissivity when bright pixels of the image pass through the transmissive LCD. Transmissivity is decreased where pixels darker than a darkening threshold pass through the transmissive LCD. A darkening curve representative of an amount of darkening performed by the transmissive LCD provides an amount of darkening to be performed on each pixel. Preferably, the darkening curve gradually darkens pixels more as the pixels themselves are darker. The darkening curve may be implemented as a formula or a look-up table in software or drive electronics that energize the transmissive LCD. Both the darkening threshold and the darkening curve may be user selectable.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.