Front projection screen
AssigneeU.S. Philips Corporation
InventorJohannes C. Van De Ven
Life of this patent
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Abstract
A front projection screen comprises a transparent plate, the front and rear sides of which have linear Fresnel structures crossing each other and whose rear side is reflective. The riser facets, termed edges, of at least the rear Fresnel lens structure, are substantially perpendicular to the plane of the plate. Ambient light incident on the screen leaves the screen on the rear side via the edges on the rear side or are absorbed by light absorbing material on the edges. This results in an enhancement of the contrast in the observed picture. Further measures enhancing the contrast are the provision of wedge-shaped indentations in the rear side of the plate.
Claims10
A front projection screen for visibly displaying an image in an audience space, which image is supplied by an image beam from a primary image source, said screen comprising a plate having a front side facing the audience space and the image source, said plate having a Fresnel structure for converging the image beam in the audience space and having means for spreading light of the image beam in the audience space, the plate being transparent and a rear side of the plate remote from the audience space being provided with reflecting means and with a relief structure comprising faces which are substantially perpendicular to the plane of the plate characterized in that the faces comprise light absorbing material.
Dependencies are inferred from the claim text.