Rear projection screen using internal reflection
First Claim
1. A light dispersing film for a rear projection screen, comprising:
- a first layer formed from a first material having a first refractive index, the first layer having first and second opposing sides and an optical axis normal to the first side, the first layer including structures formed from a second material having a second refractive index smaller than the first refractive index, the structures having bases at the second side with one or more side walls extending towards the first side, first internal reflecting surfaces being formed by interfaces between the first and second materials, the structure bases including a light absorbing material, optically transmitting areas of the second side being defined between the structure bases, the first internally reflecting surfaces forming reflecting units that asymmetrically disperse light through respective optically transmitting areas, the first reflecting surfaces forming surfaces disposed at at least two angles relative to the optical axis.
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Accused Products
Abstract
An optically dispersing film for a rear projection system includes reflecting surfaces disposed so as to reflect light passing therethrough into at least one dispersion plane. The reflecting surfaces are formed by structures, of a first refractive index, disposed within a layer of material having a second refractive index. The structures have light absorbing bases at the viewing side of the film. In some embodiments, the reflecting surfaces are disposed at one or more angles so as to reflect light into a number of different directions. In other embodiments, the layer of material having the second refractive index includes diffusing particles that diffuse the light. The film permits the asymmetric dispersion of image light in a rear projection system, so that the light may be selectively directed towards the viewer.
133 Citations
69 Claims
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1. A light dispersing film for a rear projection screen, comprising:
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a first layer formed from a first material having a first refractive index, the first layer having first and second opposing sides and an optical axis normal to the first side, the first layer including structures formed from a second material having a second refractive index smaller than the first refractive index, the structures having bases at the second side with one or more side walls extending towards the first side, first internal reflecting surfaces being formed by interfaces between the first and second materials, the structure bases including a light absorbing material, optically transmitting areas of the second side being defined between the structure bases, the first internally reflecting surfaces forming reflecting units that asymmetrically disperse light through respective optically transmitting areas, the first reflecting surfaces forming surfaces disposed at at least two angles relative to the optical axis. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A light dispersing film for a rear projection screen, comprising:
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a first layer formed from a first material having a first refractive index, the first layer having first and second opposing sides and a first optical axis normal to the first side, the first layer including structures formed from a second material having a second refractive index smaller than the first refractive index, the structures having bases at the second side with one or more side walls extending towards the first side to define first reflecting surfaces, the structure bases including a light absorbing material, optically transmitting areas of the second side being defined between the structure bases, the first reflecting surfaces forming reflecting units that asymmetrically disperse light through respective optically transmitting areas, and the first reflecting surfaces being disposed to reflect light to more than two selected directions within a dispersion plane. - View Dependent Claims (24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41)
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42. A light dispersing film for a rear projection screen, comprising:
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a first layer formed from a first material having a first refractive index, the first layer having first and second opposing sides and a first optical axis normal to the first side, the first layer including structures formed from a second material having a second refractive index smaller than the first refractive index, the structures having bases at the second side with one or more side walls extending towards the first side to define first reflecting surfaces, the structure bases including a light absorbing material, optically transmitting areas of the second side being defined between the structure bases, the first reflecting surfaces forming surfaces disposed at two or more angles relative to the optical axis, a first structure defining a first inclusion angle different from a second inclusion angle defined by a second structure, a bisector of the first inclusion angle being parallel to a bisector of the second inclusion angle, and wherein all light reflected by the first reflecting surfaces is reflected at dielectric-dielectric interfaces. - View Dependent Claims (43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53)
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54. A film for a rear projection screen, comprising:
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a substrate layer, having a first substrate layer side;
structures, formed from a first material having a first refractive index, having structure bases disposed on the first substrate layer side, sidewalls of the structures extending in directions away from the substrate, structure bases being formed of light absorbing material, and clear areas being defined on the first substrate layer side between the structure bases; and
an overlayer, formed from a second material having a second refractive index larger than the first refractive index, disposed over the structures and the clear areas of the first substrate layer side, interfaces between the overlayer and the sidewalls forming internally reflecting surfaces for light propagating within the overlayer towards the substrate in a direction substantially perpendicular to the substrate, the overlayer including diffusing particles. - View Dependent Claims (55, 56, 57, 58, 59, 60, 61, 62, 63, 64)
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65. A method of manufacturing an optical film, comprising:
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casting and curing structures on a substrate, the structures being formed from a first material having a first refractive index and with optically absorbing bases on the substrate, open substrate areas being defined between adjacent structures on the substrate;
overcoating the structures and the open substrate areas with a second material having a second refractive index greater than the first refractive index, so as to form reflecting surfaces at interfaces between the first and second materials, the reflecting surfaces disposed to reflect light, propagating through the second material in a direction substantially parallel to an optical axis of the film, towards open substrate areas.
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66. A light dispersing film for a rear projection screen, comprising:
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a first layer formed from a first material having a first refractive index, the first layer having first and second opposing sides and a first optical axis normal to the first side, the first layer including structures formed from a second material having a second refractive index smaller than the first refractive index, the structures having bases at the second side with at least two side walls extending towards the first side, internal reflecting surfaces being formed by interfaces between the first and second materials, the structure bases including a light absorbing material, optically transmitting areas of the second side being defined between the structure bases, at least one structure having at least one of the two sidewalls disposed at an angle selected to be parallel to diverging light passing through the film from an image light source positioned on the first optical axis. - View Dependent Claims (67)
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68. A light dispersing film for a rear projection screen, comprising:
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a first film having first and second opposing sides, and having a first refractive index within a first refractive index range, the first film including structures formed from a structure material having a second refractive index less than the first refractive index range, the structures having bases at the second side with one or more side walls extending towards the first side, first internal reflecting surfaces being formed by interfaces between the structure material and material of the first film, the structure bases including a light absorbing material, optically transmitting areas of the second side being defined between the structure bases, the first refractive index of the first film proximate the first side being different from the first refractive index of the first film proximate the second side.
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69. A method of forming an optical film, comprising:
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casting and curing structures on a substrate, the structures being formed from a first material and with optically absorbing bases on the substrate, open substrate areas being defined between adjacent structures on the substrate;
disposing a metallic layer over at least part of the structures to form reflecting surfaces, the reflecting surfaces being disposed to reflect light, propagating through second material substrate in a direction substantially parallel to an optical axis of the film, towards open substrate areas; and
overcoating the metallic layer and the open substrate areas with a second material.
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Specification