Segmented light pipe apparatus and method for increasing luminous efficiency of single light-valve, color video projection displays
US6334685B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Mar 23, 2000 |
| Grant date | Jan 1, 2002 |
| Priority date | — |
| Expiry date | Mar 23, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N9/3117
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A color sequential video projector (10) employs a color modulating device (22) and a segmented light pipe (30) that coact to provide a high luminous efficiency. The color modulating device splits polychromatic light into three different colored light beams (24, 26, 28) that are positionally stationary, but alternate mutually exclusive colors sequentially with time such that each pixel of a light valve (48) is exposed to all three colors during an image frame time. The segmented light pipe receives the three light beams and forms three adjacent color bands that are precisely aligned on the light valve. Because all three colors of light are constantly illuminating the light valve, light losses are substantially eliminated. The color modulating device employs multiple color wheels (82, 84, 86) each having filter segments (90, 92, 94) that form the three light beams by reflecting the alternating, mutual exclusive colors as the wheels rotate. Alternative embodiments employ one, two, or three color wheels having flat or conically-shaped filter segment surfaces. The segmented light pipe includes three rectangular glass cores (70, 72, 74) surrounded by a low index cladding (78) and having …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.