Reflecting image projection screen and image projection system comprising such a screen
First Claim
1. A reflecting image projection screen comprising a linear polarizer and a reflecting layer for reflecting radiation which is incident on the reflecting layer via the polarizer, characterized in that the reflecting layer is a depolarizing diffuser layer and in that the image projection screen includes a cholesteric filter between the polarizer and the reflecting layer and a λ
- /4 plate between the polarizer and the cholesteric filter, the direction of polarization of the radiation from the cholesteric filter corresponding to the direction of polarization of the polarizer after conversion by the λ
/4 plate.
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Abstract
A reflecting image projection screen (1) is described, as well as an image projection system (17) in which such a projection screen (1) is used. Viewed from the front side (3) of the projection screen (1), the image projection screen comprises, in this order, a linear polarizer (9), a λ/4 plate (11), a reflecting polarizer (13) in the form of a cholesteric filter and a reflecting layer (15) which is also active as a depolarizing diffuser layer. By combining a cholesteric filter (13) with a depolarizing reflecting layer (15), an image projection screen is obtained which is highly reflective to the direction of polarization supplied by the image projector (19) and substantially absorbs the other direction of polarization.
89 Citations
15 Claims
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1. A reflecting image projection screen comprising a linear polarizer and a reflecting layer for reflecting radiation which is incident on the reflecting layer via the polarizer, characterized in that the reflecting layer is a depolarizing diffuser layer and in that the image projection screen includes a cholesteric filter between the polarizer and the reflecting layer and a λ
- /4 plate between the polarizer and the cholesteric filter, the direction of polarization of the radiation from the cholesteric filter corresponding to the direction of polarization of the polarizer after conversion by the λ
/4 plate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
- /4 plate between the polarizer and the cholesteric filter, the direction of polarization of the radiation from the cholesteric filter corresponding to the direction of polarization of the polarizer after conversion by the λ
Specification