Rear projection screen for high ambient light environments having a pinhole area substantially equal to luminous area of the light source
US5546202A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 17, 1994 |
| Grant date | Aug 13, 1996 |
| Priority date | — |
| Expiry date | Jun 17, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/133526
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In a display system suitable for high ambient light environments, a lamp is used simply as a light source to illuminate a rear projection display screen, which is a matrix of tiny cells that modulate the light at video rates. Each cell includes a polymer dispersed liquid crystal (PDLC), a focusing lens and a pinhole aperture. When the PDLC is electrically activated, light passing through the PDLC is scattered in many directions, and very little light passes through the pinhole aperture and is seen by the viewer. When the PDLC is not electrically activated, light passing through the PDLC is not scattered, the lens of each cell focuses the light through the pinhole aperture, and the viewer sees a bright spot of light.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.