Illumination unit and projection type image display apparatus employing the same
US7331680B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 26, 2005 |
| Grant date | Feb 19, 2008 |
| Priority date | — |
| Expiry date | Aug 3, 2026 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B33/06
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An illumination unit with an improved color synthesis prism, which can synthesize light beams emitted from compact light sources, and a projection type image display apparatus employing the illumination unit. The illumination unit includes first, second, and third light source units to emit first, second, and third light beams of different wavelength bands, a first triangular prism including a first entrance surface through which the first beam emitted from the first light source unit is incident, a first exit/reflection surface inclined with respect to the first entrance surface, and a second entrance surface on which the first light beam reflected by the first exit/reflection surface and the second light beam emitted from the second light source unit are incident, a second triangular prism including a third entrance surface through which the third light beam emitted from the third light source unit is incident, a second exit/reflection surface inclined with respect to the third entrance surface, and a fourth entrance surface facing the first exit/reflection surface and spaced a predetermined distance from the first exit/reflection surface, a first color filter formed on the secon…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.