Illumination optical system and projection-type image display apparatus
US6347014B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 8, 1999 |
| Grant date | Feb 12, 2002 |
| Priority date | — |
| Expiry date | Dec 8, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03B21/2073
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An illumination optical system has a light source that emits white light having random polarization planes, a polarization separation device that separates the light from the light source into two types of light having polarization planes perpendicular to each other and traveling in directions at an angle to each other, a wavelength-specific polarization conversion device that receives the two types of light thus separated and that then subjects the light of a particular wavelength range included in them to polarization conversion, a convergence optical system that receives the two types of light after the light of the particular wavelength range included therein has undergone polarization conversion and that then makes them converge on different convergence positions, and a half-wave plate disposed near one of those convergence positions. This illumination optical system outputs white light that has different polarization planes in a particular wavelength range and in other wavelength ranges, and thus, when the light is subjected to color separation by being separated into light of the particular wavelength range and light of other wavelength ranges, the difference of the polariza…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.