Solid state based illumination source for a projection display
US6364487B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 29, 1999 |
| Grant date | Apr 2, 2002 |
| Priority date | — |
| Expiry date | Jan 29, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B21/2073
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An illumination source for use in projectors and the like. The illumination source includes a light source that generates a two-dimensional emission pattern having a light intensity that varies as a function of position in the emission pattern. A collector collects the light from the light source and illuminates an exit aperture therewith. The illuminated exit aperture has a two-dimensional emission pattern with a light intensity that varies as a function of position in a manner that is more uniform as a function of position than the emission pattern of the light source. An imaging optical element images the exit aperture onto a surface. The collector is preferably a compound parabolic concentrator or a compound elliptical concentrator. In one embodiment of the invention, a partially reflecting film is placed between the exit aperture and the imaging optical element. The partially reflecting film reflects light of a first polarization state back into the collector and transmits light of the orthogonal polarization state. In another embodiment of the invention, a quarter wave plate is introduced between the exit aperture and the partially reflecting film to further increase the radi…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.