Projection-type display apparatus
US5909944A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 3, 1998 |
| Grant date | Jun 8, 1999 |
| Priority date | — |
| Expiry date | Mar 3, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/3182
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A projection-type display apparatus in which the entry of light rays to the back side of liquid crystal light valves from dichroic prism that composes optical system light synthesizer is prevented. To this end, a projection display according to the present invention preferably includes a color synthesizer for combining colored and modulated light beams, comprising: a square column dichroic prism composed of four triangle prisms having equal refractive index together whose cross sections are right isosceles triangles such that three light valves are located adjacent to three exterior peripheral surfaces of dichroic prism to receive colored and modulated light beams therefrom and; a filter for absorbing light with a specified wavelength range, leaked from surface of dichroic prism at the opposite side of incident light surface and directed to liquid crystal light valve, the filter being located between liquid crystal light valves and surface of dichroic prism. As for construction of the dichroic prism itself, specifically, of the four aforementioned triangular prisms, the first triangular prism and the aforementioned third triangular prism are mutually affixed in a condition in which…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.