Transmission holographic diffuser made and used to effect lateral color constancy in rear screen projection display systems
First Claim
1. A projection screen for the viewing from the front side thereof of a multicolor image projected rearwardly to said projection screen, said projection screen comprising in order:
- (a) a rigid light-transmissive faceplate transmissive of color separation images in overlapping registration for combination into said multicolor image;
(b) a holographic transmission diffuser element proximate said faceplate, said holographic transmission diffuser element comprising a light-transmissive substrate transmissive of said color separation images and having deposited thereon a holographic transmission diffuser element, said diffuser element, upon impingement with a light beam of 400 nm to 700 nm wavelength and an incident input angle of approximately ±
0°
to 10°
relative to normal incidence, producing a single elliptical output lobe of diffuse light, the output lobe produced in each area of said holographic transmission diffuser element having a relative angular intensity distribution and aspect ratio substantially identical to the relative angular intensity distribution and aspect ratio of output lobes produced in each other area of said holographic transmission diffuser element; and
(c) a light collimating element proximate said holographic transmission diffuser element.
14 Assignments
0 Petitions
Accused Products
Abstract
A projection screen is provided having a construction well-suited for effecting lateral color constancy in rear screen projection display systems. The inventive projection screen comprises a rigid light-transmissive faceplate and a homogenizing holographic transmission diffuser element proximate said faceplate. The holographic transmission diffuser element is made such that, upon illumination of an area of said diffuser element with a light beam having a wavelength of 400 nm to 700 nm, and impinging at an incident input angle of ±0° to 30° relative to normal incidence, said holographic transmission diffuser element produces in transmission a single diffuse output lobe, the diffuse output lobe produced in one area of said holographic transmission diffuser element having a relative angular intensity distribution and aspect ratio substantially identical to the relative angular intensity distribution and aspect ratio of diffuse output lobes produced in substantially all other areas of said holographic transmission diffuser element.
82 Citations
12 Claims
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1. A projection screen for the viewing from the front side thereof of a multicolor image projected rearwardly to said projection screen, said projection screen comprising in order:
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(a) a rigid light-transmissive faceplate transmissive of color separation images in overlapping registration for combination into said multicolor image; (b) a holographic transmission diffuser element proximate said faceplate, said holographic transmission diffuser element comprising a light-transmissive substrate transmissive of said color separation images and having deposited thereon a holographic transmission diffuser element, said diffuser element, upon impingement with a light beam of 400 nm to 700 nm wavelength and an incident input angle of approximately ±
0°
to 10°
relative to normal incidence, producing a single elliptical output lobe of diffuse light, the output lobe produced in each area of said holographic transmission diffuser element having a relative angular intensity distribution and aspect ratio substantially identical to the relative angular intensity distribution and aspect ratio of output lobes produced in each other area of said holographic transmission diffuser element; and(c) a light collimating element proximate said holographic transmission diffuser element. - View Dependent Claims (2, 3, 4, 5)
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6. A rear screen projection display system comprising:
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a cabinet with an opening in a foremost facing surface thereof; at least two horizontally-offset image projectors housed within said cabinet, each projector having a predetermined optical axis and each capable of projecting light bearing image information along a path directed ultimately toward and out of the opening in said cabinet, the projected light diverging from said optical axis as said light propagates along said path toward said opening; a light collimating element positioned along said path intercepting the diverging light propagated from each of said image projectors and collimating said light correspondent with the predetermined optical axis of the projector from which said light was propagated; and a projection screen mounted within the opening of said cabinet in a position suited for reception of the collimated light transmitted through the light collimating element, the projection screen having a holographic transmission diffuser element capable of producing a single elliptical output lobe of diffuse light upon the illumination of an area of said diffuser element with a light beam having a wavelength of 400 nm to 700 nm and impinging approximately at an angle of ±
0°
to 10°
relative to normal incidence, the output lobe produced in one area of said holographic transmission diffuser element having a relative angular intensity distribution and aspect ratio substantially identical to the relative angular intensity distribution and aspect ratio of output lobes produced in substantially all other areas of said holographic transmission diffuser element. - View Dependent Claims (7, 8, 9, 10, 11, 12)
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Specification