Rear projection television set having improved contrast
US5142373A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 5, 1990 |
| Grant date | Aug 25, 1992 |
| Priority date | — |
| Expiry date | Dec 5, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/7408
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A rear projection television set is of the construction in which an image light projected from a projection cathode ray tube is reflected by a mirror onto the rear surface of a screen comprising a Fresnel lens and the light passes through the front surface of the screen to be viewed by viewers. The condensing distance of the Fresnel lens is selected to be less than four meters for radii of up to 300(S/40) millimeters of the Fresnel lens when the mirror is positioned relative to the screen such that A.ltoreq.200+(S-40).times.10 millimeters, where S is the diagonal distance of the screen in inches and A is the shortest distance between the mirror and the screen.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.