Projection display device
US7963657B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 11, 2008 |
| Grant date | Jun 21, 2011 |
| Priority date | — |
| Expiry date | Jul 25, 2029 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/3105
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An imager is shifted with respect to an optical axis of a refractive optical system. Thereby, a throw distance of a projector is shortened. A wavelength-selective half wavelength plate for rotating a polarization direction of green light beams is disposed between a dichroic prism and the refractive optical system in such a manner that the polarization direction of the green light beams is in parallel to the shifting direction. Thereby, the green light beams are incident onto the refractive optical system as P-polarized beams, whereby a transmittance of the green light beams in the refractive optical system is increased, while suppressing lowering of the light amount of the green light beams, and color non-uniformity resulting from lowering of the light amount of the green light beams.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.