Apparatus and method for a projection device wherein the polarization direction of projected light on a transmissive projection screen is changed by means of an adjustable liquid crystal device
First Claim
1. A projection device comprising a projector for providing a light beam to be projected in polarized light, a means for changing the direction of polarization, and a transmissive projection screen, said means for changing the direction of polarization being arranged between the projector and the transmissive projection screen, characterized in that the transmissive projection screen comprises a polarizing diffusion layer, in that the extent of changing the direction of polarization of the means for changing the direction of polarization is adjustable, and in that adjusting means, coupled to the means for changing the direction of polarization, are provided for adjusting the extent of changing the direction of polarization.
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Accused Products
Abstract
A projection device comprises a projector (1) for providing a light beam (3, 13) to be projected in polarized light. A adjustable liquid crystal element (4) for changing the direction of polarization is arranged between the projector (1) and the transmissive projection screen (2). The transmissive projection screen (2) comprises a polarizing diffusion layer (9). The extent of changing the direction of polarization by the adjustable liquid crystal element (4) for changing the direction of polarization is adjustable. The extent of changing the direction of polarization and hence the extent of diffusion in the transmissive projection screen (2) is adjustable by way of adjusting the voltage from a voltage source which is coupled to the adjustable liquid crystal element (4) for changing the direction of polarization.
22 Citations
5 Claims
- 1. A projection device comprising a projector for providing a light beam to be projected in polarized light, a means for changing the direction of polarization, and a transmissive projection screen, said means for changing the direction of polarization being arranged between the projector and the transmissive projection screen, characterized in that the transmissive projection screen comprises a polarizing diffusion layer, in that the extent of changing the direction of polarization of the means for changing the direction of polarization is adjustable, and in that adjusting means, coupled to the means for changing the direction of polarization, are provided for adjusting the extent of changing the direction of polarization.
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5. A method of adjusting the diffusion of a transmissive projection screen comprising a polarizing diffusion layer the method comprising the step of adjusting the direction of polarization of the light beam by adjusting an adjustable means for changing the direction of polarization.
Specification