Devices and methods for enhancing brightness of displays using angle conversion layers
First Claim
1. An illumination apparatus comprising:
- a light guide that guides light propagating therein at an angle greater than a critical angle for the light guide and ejects light from the light guide to provide illumination;
diffractive microstructure disposed to receive an ambient light at a first angle smaller than said critical angle and to diffract said ambient light to produce diffracted light at a second larger angle, such that said diffracted light propagates through the light guide; and
light-turning features configured to turn the diffracted light and direct the turned light out of the light guide,wherein the light guide, the diffractive microstructure, and the light-turning features are disposed with respect to a spatial light modulator such that light ejected from the light guide illuminates said spatial light modulator, wherein said spatial light modulator comprises a MEMS device, wherein said MEMS device comprises interferometric modulators, wherein said MEMS device comprises first and second reflective surfaces, one of which is movable with respect to the other.
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Accused Products
Abstract
Various embodiments of the present invention relate to enhancing the brightness of displays that employ illumination systems. In some embodiments, the illumination systems include light guides, diffractive microstructure, and light-turning features. The diffractive microstructure may be configured to receive ambient light at a first angle and produce diffracted light at a second angle greater than the first angle and greater than the critical angle for of light guide. The light is thereby guided within the light guide. The light-turning features may be configured to turn the light guided within the light guide out of a light guide and onto, for example, a spatial light modulator at near normal incidence.
447 Citations
48 Claims
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1. An illumination apparatus comprising:
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a light guide that guides light propagating therein at an angle greater than a critical angle for the light guide and ejects light from the light guide to provide illumination; diffractive microstructure disposed to receive an ambient light at a first angle smaller than said critical angle and to diffract said ambient light to produce diffracted light at a second larger angle, such that said diffracted light propagates through the light guide; and light-turning features configured to turn the diffracted light and direct the turned light out of the light guide, wherein the light guide, the diffractive microstructure, and the light-turning features are disposed with respect to a spatial light modulator such that light ejected from the light guide illuminates said spatial light modulator, wherein said spatial light modulator comprises a MEMS device, wherein said MEMS device comprises interferometric modulators, wherein said MEMS device comprises first and second reflective surfaces, one of which is movable with respect to the other. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A method of manufacturing an illumination apparatus comprising:
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providing a light guide that guides light propagating therein at an angle greater than a critical angle for the light guide and ejects light therefrom to provide illumination; disposing diffractive microstructure to receive an ambient light at a first angle smaller than said critical angle and to diffract said ambient light to produce diffracted light at a second larger angle, such that said diffracted light propagates through the light guide; providing light-turning features configured to turn the diffracted light and direct the turned light out of the light guide; providing a spatial light modulator; and disposing the light guide, the diffractive microstructure, and the light-turning features with respect to a spatial light modulator such that light ejected from the light guide illuminates said spatial light modulator, wherein providing the spatial modulator comprises forming a first reflective surface, and forming a second movable reflective surface. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37)
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38. An illumination apparatus comprising:
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means for guiding light propagating therein at an angle greater than a critical angle for the light guiding means and ejecting light from the light guiding means to provide illumination; means for diffracting an ambient light received at a first angle smaller than said critical angle to produce diffracted light at a second larger angle, such that said diffracted light propagates through the light guiding means; and means for turning the diffracted light and directing the turned light out of said light guiding means, wherein the ambient light is transmitted through said turning means prior to being received by said diffracting means. - View Dependent Claims (39, 40, 41, 42)
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43. An illumination apparatus comprising:
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a light guide that guides light propagating therein at an angle greater than a critical angle for the light guide and ejects light from the light guide to provide illumination; diffractive microstructure disposed to receive an ambient light at a first angle smaller than said critical angle and to diffract said ambient light to produce diffracted light at a second larger angle, such that said diffracted light propagates through the light guide; and light-turning features configured to turn the diffracted light and direct the turned light out of the light guide, wherein the ambient light is transmitted through said light-turning features prior to being received by said diffractive microstructure.
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44. A method of manufacturing an illumination apparatus comprising:
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providing a light guide that guides light propagating therein at an angle greater than a critical angle for the light guide and ejects light therefrom to provide illumination; disposing diffractive microstructure to receive an ambient light at a first angle smaller than said critical angle and to diffract said ambient light to produce diffracted light at a second larger angle, such that said diffracted light propagates through the light guide; providing light-turning features configured to turn the diffracted light and direct the turned light out of the light guide, wherein disposing diffractive microstructure comprises providing a diffractive layer comprising the diffractive microstructure, and wherein providing light-turning features comprises providing a light-turning layer comprising the light-turning features; and disposing the light-turning layer over the diffractive layer.
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45. An illumination apparatus comprising:
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a light guide that guides light propagating therein at an angle greater than a critical angle for the light guide and ejects light from the light guide to provide illumination; diffractive microstructure disposed to receive ambient light at a first angle smaller than said critical angle and to diffract said ambient light to produce diffracted light at a second larger angle, such that said diffracted light propagates through the light guide; light-turning features configured to turn the diffracted light and direct the turned light out of the light guide; and a light-turning layer comprising said light-turning features, and a diffractive layer comprising said diffractive microstructure; wherein the light-turning layer is positioned over the diffractive layer.
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46. An illumination apparatus comprising:
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a light guide that guides light propagating therein at an angle greater than a critical angle for the light guide and ejects light from the light guide to provide illumination; diffractive microstructure disposed to receive ambient light at a first angle smaller than said critical angle and to diffract said ambient light to produce diffracted light at a second larger angle, such that said diffracted light propagates through the light guide; light-turning features configured to turn the diffracted light and direct the turned light out of the light guide; and a light-turning layer comprising said light-turning features, and a diffractive layer comprising said diffractive microstructure; wherein the light-turning layer is physically separated by one or more separation layers from the diffractive layer.
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47. An illumination apparatus comprising:
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a light guide that guides light propagating therein at an angle greater than a critical angle for the light guide and ejects light from the light guide to provide illumination; diffractive microstructure disposed to receive ambient light at a first angle smaller than said critical angle and to diffract said ambient light to produce diffracted light at a second larger angle, such that said diffracted light propagates through the light guide; light-turning features configured to turn the diffracted light and direct the turned light out of the light guide; a light-turning layer comprising said light-turning features, and a diffractive layer comprising said diffractive microstructure; and an isolation layer positioned below the diffractive layer, wherein the index of refraction of the isolation layer is less than the index of refraction of a layer positioned on the isolation layer.
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48. A method of manufacturing an illumination apparatus comprising:
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providing a light guide that guides light propagating therein at an angle greater than a critical angle for the light guide and ejects light therefrom to provide illumination; disposing diffractive microstructure to receive an ambient light at a first angle smaller than said critical angle and to diffract said ambient light to produce diffracted light at a second larger angle, such that said diffracted light propagates through the light guide; providing light-turning features configured to turn the diffracted light and direct the turned light out of the light guide, wherein disposing diffractive microstructure comprises providing a diffractive layer comprising the diffractive microstructure, and wherein providing light-turning features comprises providing a light-turning layer comprising the light-turning features, and further comprising disposing one or more separation layers over the diffractive layer and disposing the light-turning layer over the one or more separation layers.
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Specification