Optical unit and projection-type image display apparatus using the same
US7255444B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 18, 2005 |
| Grant date | Aug 14, 2007 |
| Priority date | — |
| Expiry date | Dec 12, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B21/2073
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A technique according to the present invention allows a projection-type image display system to suppress the temperature rise of the polarization split devices and secure high image quality. Polarization split means has a polarization split device arranged in a medium with a refractive index larger than 1. The polarization split device has a polarization split surface on which a diffractive grating structure is formed to polarize and split light. An air layer is formed in contact with the polarization split surface. In a projection type image display apparatus or an optical unit using this apparatus, light fluxes are polarized and split by the polarization split means before irradiated to light valves and after modulated by the light valves and color composition is made from the polarized and split light fluxes before enlarged and projected by a projection lens unit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.