Rear projection screen with high off-axis sunlight rejection
US5543870A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 6, 1994 |
| Grant date | Aug 6, 1996 |
| Priority date | — |
| Expiry date | Oct 6, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/133524
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A projection system having a rear projection screen (28) employs a collimating lens (26) in the form of a Fresnel lens adjacent the rear surface of the screen (28) to improve the image luminance at various viewing angles and provide uniform brightness over the area of the screen. A fiber optic face plate (30) or two crossed films of microlouver light control material is interposed between the collimating Fresnel lens (26) and the rear of the projection screen (28) to provide a high degree of blocking of high intensity light, such as sunlight, that may impinge upon the front of the screen. The optical fibers (42) of the fiber optic face plate have a low numerical aperture and an opaque cladding. The arrangement allows an image to be provided on the screen with high contrast even in the presence of sunlight striking the screen.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.