Liquid crystal display projection system using multilayer optical film polarizers
First Claim
1. A liquid crystal projector system, comprising:
- a light source;
a liquid crystal light modulator;
a reflective polarizer disposed between the light source and the light modulator, the reflective polarizer including layers of a first material and a second material having a refractive index difference between the first and second material along a first axis which is large enough to substantially reflect light of a first polarization state and a refractive index difference between the first and second material along a second axis, orthogonal to the first axis, which is small enough to substantially transmit light of a second polarization state;
a reflector disposed to redirect light reflected by the reflective polarizer; and
a retarder film disposed between the reflector and the reflective polarizer,wherein at least 15% of light of the first polarization state reflected by the reflective polarizer is converted to the second polarization state and redirected for transmission to the light modulator by the reflector and retarder film.
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Accused Products
Abstract
A liquid crystal display (LCD) projection system including a projection panel, a light source, and a reflector. The projection panel includes an LCD and a polarizer on one side of the LCD and a reflective polarizer on the other side. The reflective polarizer is a multilayer stack of pairs of adjacent material layers. Each of the layer pairs exhibits a refractive index difference between the adjacent layers in a first direction in the plane of the reflective polarizer and exhibits essentially no refractive index difference between adjacent layers in a second direction in the plane of the reflective polarizer and orthogonal to the first direction. A quarter-wave plate is secured to the reflective polarizer. Light rays from the light source either pass through the reflective polarizer, and on to the LCD, or are reflected back toward the light source, depending on their polarization. Light which is reflected by the reflective polarizer is reflected by the reflector back toward the LCD again. The use of the quarter-wave plate and the reflector help to recycle what would typically be regarded as wasted light, while at the same time reducing heat build-up within the LCD.
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Citations
19 Claims
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1. A liquid crystal projector system, comprising:
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a light source; a liquid crystal light modulator; a reflective polarizer disposed between the light source and the light modulator, the reflective polarizer including layers of a first material and a second material having a refractive index difference between the first and second material along a first axis which is large enough to substantially reflect light of a first polarization state and a refractive index difference between the first and second material along a second axis, orthogonal to the first axis, which is small enough to substantially transmit light of a second polarization state; a reflector disposed to redirect light reflected by the reflective polarizer; and a retarder film disposed between the reflector and the reflective polarizer, wherein at least 15% of light of the first polarization state reflected by the reflective polarizer is converted to the second polarization state and redirected for transmission to the light modulator by the reflector and retarder film. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification