Illumination apparatus and liquid crystal projector using the illumination apparatus
US7077546B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 24, 2005 |
| Grant date | Jul 18, 2006 |
| Priority date | — |
| Expiry date | Jan 24, 2025 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/3167
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An illumination apparatus includes a reflector including a parabolic or ellipsoidal mirror, a light source arranged near a (first) focal point of the reflector, and a front mirror having a transparent window and a mirror surface symmetrical about the light axis. Luminous flux emitted from the light source is reflected from the reflector. In the case of the parabolic mirror, the front mirror has the same size as an entrance of an output light utilizing optical system, and the luminous flux exits toward the optical system as collimated light. In the case of the ellipsoidal mirror, the front mirror is arranged between two focal points of the ellipsoidal mirror, and the luminous flux is directed toward the second focal point. However, at least one part of the luminous flux is reflected from the front mirror and returned toward the first focal point.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.