RECYCLING BACKLIGHTS WITH SEMI-SPECULAR COMPONENTS
First Claim
Patent Images
1. A backlight, comprising:
- a front and back reflector forming a hollow light recycling cavity, the front reflector being partially transmissive to provide an output illumination area, and wherein the front reflector has a reflectivity for p-polarized light that is;
(1) constant, or (2) increases, with angle of incidence, and a transmission that generally decreases with angle of incidence;
a component that provides the cavity with a desired balance of specular and diffuse characteristics, the component being characterized by a transport ratio greater than 15% at a 15 degree incidence angle and less than 95% at a 45 degree incidence angle, wherein the front or back reflectors can be or include the component, or the component can be distinct from the front and back reflectors; and
one or more light source members disposed to emit light into the light recycling cavity over a limited angular distribution.
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Abstract
A recycling cavity such as used in a backlight or similar extended area source includes a front and back reflector, the front reflector being partially transmissive to provide an output illumination area. The recycling cavity also includes a component that provides the cavity with a balance of specular and diffuse characteristics so as to balance cavity efficiency and brightness uniformity over the output area. The component can be characterized by a transport ratio of greater than 15% for a 15 degree incidence angle, and less than 95% for a 45 degree incidence angle.
3 Citations
20 Claims
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1. A backlight, comprising:
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a front and back reflector forming a hollow light recycling cavity, the front reflector being partially transmissive to provide an output illumination area, and wherein the front reflector has a reflectivity for p-polarized light that is;
(1) constant, or (2) increases, with angle of incidence, and a transmission that generally decreases with angle of incidence;a component that provides the cavity with a desired balance of specular and diffuse characteristics, the component being characterized by a transport ratio greater than 15% at a 15 degree incidence angle and less than 95% at a 45 degree incidence angle, wherein the front or back reflectors can be or include the component, or the component can be distinct from the front and back reflectors; and one or more light source members disposed to emit light into the light recycling cavity over a limited angular distribution. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A backlight, comprising:
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a front and back reflector forming a light recycling cavity, the front reflector being partially transmissive to provide an output illumination area, and wherein the front reflector has a reflectivity for p-polarized light that is;
(1) constant, or (2) increases, with angle of incidence, and a transmission that generally decreases with angle of incidence;a component that provides the cavity with a desired balance of specular and diffuse characteristics, the component being characterized by a transport ratio greater than 15% at a 15 degree incidence angle and less than 95% at a 45 degree incidence angle, wherein the front or back reflectors can be or include the component, or the component can be distinct from the front and back reflectors; and one or more light source members disposed to emit light into the light recycling cavity over a limited angular distribution; wherein the cavity comprises a cavity transport value of greater than about 0.5 and less than about 0.95. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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Specification