Image projection system with improved contrast having single birefringence-compensating element
AssigneeKoninklijke Philips Electronics N.V.
InventorMaarten Kuijper
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Abstract
The present invention relates to an image projection system (1) comprising an illumination system (3) for supplying an illumination beam, a modulation system (11) for modulating said illumination beam, and an optical system for projecting an image. The modulation system (11) comprises at least one image display panel of the TN type. The liquid crystal layer (13) is enclosed between a first polarizer (12) and a second polarizer (14). A single birefringence-compensating element (27) is present between the liquid crystal layer (13) and one of the polarizers (12; 14). The element (27) has a tilted director profile whose projection in the plane of the polarizers encloses an angle 0°<φ≦15° with the active rubbing direction of the liquid crystal layer.
Claims9
An image projection system comprising an illumination system for supplying an illumination beam, a modulation system for modulating said illumination beam in conformity with image information to be projected, and an optical system for projecting an image, said modulation system comprising at least one liquid crystalline image display panel having a first and a second polarizer between which a layer of TN (twisted nematic) liquid crystalline material is enclosed, characterized in that a single birefringence-compensating element is located between the layer of TN (twisted nematic) liquid crystalline material and one of the two polarizers, which element is present on that side of the liquid crystalline material having its active rubbing direction and which element has a tilted optical director profile whose projection in the plane of the polarizers encloses an angle φ having a value 0°<φ≦15° with the active rubbing direction of the layer.
Dependencies are inferred from the claim text.