Projection display device
US6773116B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 22, 2002 |
| Grant date | Aug 10, 2004 |
| Priority date | — |
| Expiry date | May 22, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/7441
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The invention relates to a projection display device comprising an illumination system having a light source and an optical guiding means for providing an illumination beam, and an image display system for modulating the illumination beam with image information and projecting the image on a screen, and means for selectively transmitting a portion of the illumination beam having a desired characteristic to the image display system, and means for feeding back an unused portion of the illumination beam to the illumination system for re-illumination of the image display system. In order to improve the efficiency of the projection display device, a reflection means is provided at a portion of an entrance surface of the light-guiding means and the unused portion of the illumination beam is fed back into the light-guiding means.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.