Polarization sensitive light homogenizer
First Claim
1. A light homogenizer for improving the spatial luminance uniformity of incident light comprising:
- a first polarization dependent anisotropic light scattering region comprising a first continuous phase of a first material and a first dispersed phase of a second material contained as a first plurality of domains in said first continuous phase and one or more of said first plurality of domains are ellipsoidal in shape;
a first light redirecting region adapted to receive light within a predetermined first range of input angles from said first polarization dependent anisotropic light scattering region and redirect a first portion of the light back toward said polarization dependent anisotropic light scattering region;
wherein the refractive index difference between said first material and said second material along a first and second of three mutually orthogonal axes is greater than 0.01 and the refractive index difference along at least one axis is less than 0.1;
wherein transmitted visible light is anisotropically scattered and visible light of all polarization states is partially transmitted anisotropically and partially reflected;
a first optical cavity bounded by said first light redirecting region and one or more of said first plurality of domains wherein incident light undergoes multiple redirections and multiple scatterings whereby the spatial uniformity of the light is increased.
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Accused Products
Abstract
The present invention provides a polarization-sensitive light homogenizer and a backlight and display using the same. The homogenizer improves the spatial luminance and color uniformity, increases the luminance in a direction normal to the homogenizer and provides increased luminance through polarized light recycling within the light homogenizer and backlight. In one embodiment, the homogenizer includes a polarization-sensitive anisotropic light-scattering (PDALS) region, a non-polarization-sensitive anisotropic light-scattering region, and a substantially non-scattering region. In a further embodiment, the non-scattering region is birefringent. The spatially non-uniform incident light flux from a backlight including one or more non-extended light emitting sources is scattered efficiently by the NPDASL region and is incident on the PDALS region which backscatters light orthogonal to the polarization state desired for efficient illumination of a liquid crystal display panel. The NPDASL and the PDALS form a multiple reflection cavity that will increase the spatial luminance while improving the light recycling of the appropriate polarization state. In a further embodiment the light homogenizer includes at least one of a light collimating region and a light re-directing region.
159 Citations
20 Claims
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1. A light homogenizer for improving the spatial luminance uniformity of incident light comprising:
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a first polarization dependent anisotropic light scattering region comprising a first continuous phase of a first material and a first dispersed phase of a second material contained as a first plurality of domains in said first continuous phase and one or more of said first plurality of domains are ellipsoidal in shape; a first light redirecting region adapted to receive light within a predetermined first range of input angles from said first polarization dependent anisotropic light scattering region and redirect a first portion of the light back toward said polarization dependent anisotropic light scattering region; wherein the refractive index difference between said first material and said second material along a first and second of three mutually orthogonal axes is greater than 0.01 and the refractive index difference along at least one axis is less than 0.1; wherein transmitted visible light is anisotropically scattered and visible light of all polarization states is partially transmitted anisotropically and partially reflected; a first optical cavity bounded by said first light redirecting region and one or more of said first plurality of domains wherein incident light undergoes multiple redirections and multiple scatterings whereby the spatial uniformity of the light is increased. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A light emitting assembly for emitting light which is substantially uniform spatially comprising:
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a housing; a light source; a light homogenizer; said light homogenizer comprising a first polarization dependent anisotropic light scattering region comprising a first continuous phase of a first material and a first dispersed phase of a second material contained as a first plurality of domains in said first continuous phase and one or more of said first plurality of domains are ellipsoidal in shape; a first light redirecting region adapted to receive light within a predetermined first angular input range from said first polarization dependent anisotropic light scattering region and redirect a first portion of the light back toward said polarization dependent anisotropic light scattering region; wherein the refractive index difference between said first material and said second material along a first and second of three mutually orthogonal axes is greater than 0.01 and the refractive index difference along at least one axis is less than 0.1; wherein transmitted visible light is anisotropically scattered and visible light of all polarization states is partially transmitted anisotropically and partially reflected; a first optical cavity bounded by said first light redirecting region and one or more of said first plurality of domains wherein incident light undergoes multiple redirections and multiple scatterings whereby the spatial uniformity of the light is increased, wherein said light homogenizer is disposed to receive light originating from the said light source. - View Dependent Claims (18, 19, 20)
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Specification