Holographic projection screen combining an elliptical holographic diffuser and a cylindrical light-collimator
First Claim
1. A projection screen for the viewing from the front side thereof of a multicolor image transmitted by projection therethrough projection screen having vertical and horizontal viewing axes and comprising:
- (a) a holographic transmission diffuser element capable of diffusing a beam of light into a forwardly-projected horizontally-elliptical cone; and
(b) a light-collimating element capable of uniaxially-collimating by transmission an expanding wavefront projected therethrough, the light-collimating element positioned in substantially overlapping relationship with the holographic transmission diffuser element such that the axis of collimation of said light-collimating element is substantially orthogonal to said horizontal viewing axis.
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Accused Products
Abstract
A projection screen having a construction well-suited for effecting lateral color constancy in rear screen projection display systems is disclosed. The projection screen includes a holographic transmission diffuser element capable of diffusing a beam of light into a horizontally-elliptical cone and a light-collimating element for uniaxially-collimating by transmission an expanding wavefront with the axis of collimation substantially orthogonal to a horizontal viewing axis. The use of the projection screen in a rear screen projection display system including red, green and blue image projectors is also disclosed. A method of manufacturing a holographic projection screen by drawing a holographic transmission diffuser web and a uniaxial light collimating web into overlapping relationship and bonding the webs is also disclosed.
98 Citations
12 Claims
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1. A projection screen for the viewing from the front side thereof of a multicolor image transmitted by projection therethrough projection screen having vertical and horizontal viewing axes and comprising:
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(a) a holographic transmission diffuser element capable of diffusing a beam of light into a forwardly-projected horizontally-elliptical cone; and (b) a light-collimating element capable of uniaxially-collimating by transmission an expanding wavefront projected therethrough, the light-collimating element positioned in substantially overlapping relationship with the holographic transmission diffuser element such that the axis of collimation of said light-collimating element is substantially orthogonal to said horizontal viewing axis. - View Dependent Claims (2, 3)
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4. 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; and a projection screen fitted into said opening to thereby intercept the diverging light propagated from each of said image projectors, the projection screen comprising (a) a holographic transmission diffuser element having a horizontal viewing axis and capable of diffusing a beam of light projected from any of said image projectors into a forwardly-projected horizontally-elliptical cone, and (b) a uniaxial light-collimating element positioned proximate to and in substantially overlapping relationship with said holographic transmission diffuser element, the light-collimating element positioned with its collimating axis substantially orthogonal to the horizontal viewing axis of said holographic transmission diffuser element. - View Dependent Claims (5, 6, 7, 8, 9)
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10. A method of manufacturing a holographic projection screen, the projection screen comprising a holographic transmission diffuser element having a predetermined horizontal viewing axis and a uniaxial light-collimating element, the method comprising the steps of:
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(a) providing on a first spool a continuous web of said holographic transmission diffuser element, said predetermined horizontal viewing axis being in alignment with the cross-web axis of said continuous web of said holographic transmission diffuser element; (b) providing on a second spool a continuous web of said uniaxial light-collimating element, the axis of collimation of said light-collimating element being in alignment with the cross-web axis of said continuous web of said light-collimating element; (c) drawing into substantially overlapping relationship a length of the web from said first spool and a length of the web from said second spool, whereby in the resulting area of overlap, said axis of collimation is substantially orthogonal to said predetermined horizontal viewing axis; (d) bonding together the lengths of webs within said area of overlap; and (e) removing the bonded lengths of webs within said area of overlap. - View Dependent Claims (11, 12)
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Specification