REAR PROJECTION SYSTEM AND REAR PROJECTION SCREEN
First Claim
1. A rear projection system comprisinga projector (18), anda projection screen (16) being switchable between a transparent mode and a diffractive mode,wherein the projector (18) is located with respect to the projection screen (16) such that light from the projector (18) is incident at an inclined angle at the rear side of the projection screen (16), the projection screen (16) is adapted to deflect in its diffractive mode the incident light into a limited angular range with respect to the front surface normal of the projection screen (16).
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Accused Products
Abstract
To provide a rear projection system, which offers a high transparency and a high efficiency of projection, a rear projection system is proposed, comprising: a projector (18), and a projection screen (16) being switchable between a transparent mode and a diffractive mode, wherein the projector (18) is located with respect to the projection screen (16) such that light from the projector (18) is incident at an inclined angle at the rear side of the projection screen (16), the projection screen (16) is adapted to deflect in its diffractive mode the incident light into a limited angle range with respect to the front surface normal of the screen (16).
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Citations
17 Claims
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1. A rear projection system comprising
a projector (18), and a projection screen (16) being switchable between a transparent mode and a diffractive mode, wherein the projector (18) is located with respect to the projection screen (16) such that light from the projector (18) is incident at an inclined angle at the rear side of the projection screen (16), the projection screen (16) is adapted to deflect in its diffractive mode the incident light into a limited angular range with respect to the front surface normal of the projection screen (16).
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12. A rear projection screen (116) being switchable between a transparent mode and a diffractive mode, the projection screen (116) comprises:
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a first transparent substrate (54) comprising a first transparent electrode (56) and a relief portion with a surface-relief grating (58), a liquid crystal material (72) located next to the relief portion of the first transparent substrate (54) and filling the surface-relief grating (58), a second transparent substrate (64) with a second transparent electrode (66), wherein the refractive index of the liquid crystal material (72) could be changed by means of electrical field of the first and second electrode (56, 66) to be substantially equal or different from the refractive index of the relief portion of the first transparent substrate (54). - View Dependent Claims (13, 14, 15, 16, 17)
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Specification