Projection display system including a collimating tapered waveguide or lens with the normal to optical axis angle increasing toward the lens center
US5459592A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 21, 1993 |
| Grant date | Oct 17, 1995 |
| Priority date | — |
| Expiry date | Apr 21, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/1336
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The present invention provides a lighting device including a light source; a reflecting mirror for reflecting light emitted by the light source in a determined direction; and a compensating element for receiving the light from the reflecting mirror and allowing the light to outgo in the form of parallel rays. Further, a projection type image display system including the above-mentioned lighting device and a display element for forming an image by receiving light from the lighting device is provided. According to the present invention, light can be emitted with a satisfactory degree of parallelization and an even illuminance, constant irregularity due to the photoelasticity can be degraded, and the degradation in brightness of a projected image due to a low ratio of aperture can be avoided. Thus, a uniform image with no illuminance irregularity can be projected.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.