Projection-type color display device with light valves positioned at unequal distances from the light source
US4909601A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 13, 1988 |
| Grant date | Mar 20, 1990 |
| Priority date | — |
| Expiry date | Apr 13, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/3105
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A projection-type display device for producing a well balanced color image without the use of a neutral density filter. The device includes three liquid crystal light valves associated with the three primary colors and two dichroic mirrors. A light source generates colored light. The optical length between the light source and the light valve associated with the primary color of the colored light having the highest level of luminous intensity is greater than the optical lengths between the light source and each of the other two light valves. One of the three liquid crystal light valves is driven by circuitry to produce an image which is a mirror image of the images produced by the other two light valves.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.