Optical: systems and elements – Projection screen – Unitary sheet comprising plural refracting areas
Patent
1998-04-08
2000-04-04
Metjahic, Safet
Optical: systems and elements
Projection screen
Unitary sheet comprising plural refracting areas
359742, G03B 2160, G02B 308
Patent
active
060468475
ABSTRACT:
A Fresnel lens sheet (11) used in combination with a lenticular lens sheet (12) to form a rear projection screen of a TV set, has Fresnel lens elements (15) on a front surface thereof. The Fresnel lens elements (15) include a first group of Fresnel lens elements (15a) and a second group of Fresnel lens elements (15b). The first group of lens elements (15a) has a first focal length (f.sub.1) which is greater than a second focal length (f.sub.2) of the second group of lens elements (15b). The first group lens elements (15a) and the second group of lens elements (15b) are disposed alternately. The above configuration provides an increased vertical angular range of a viewing region from which pictures displayed on the rear projection screen can be viewed satisfactorily, as well as an increased luminance of the rear projection screen.
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Dai Nippon Printing Co. Ltd.
Mahoney Christopher E.
Metjahic Safet
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