Method and apparatus for adjusting light intensity
US7349048B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Dec 16, 2004 |
| Grant date | Mar 25, 2008 |
| Priority date | — |
| Expiry date | Oct 6, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/136277
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A variable retarder and linear polarizer are placed in series in a polarized light path. A transmission axis of the linear polarizer is parallel to an axis of a polarization of the polarized light. An amount of retardation dialed into the variable retarder causes an amount of the light to have a component with an amount of off axis polarization. The off-axis components do not pass the linear polarizer, causing a reduction in the brightness of the polarized light. The combined variable retarder and linear polarizer operate as a light shutter that may be utilized, for example, to increase contrast ratio and bit depth regardless of light level in a video projection system (e.g., LCoS light engines).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.