Laser illuminated projection displays
First Claim
1. A projection display, comprising:
- at least one laser for delivering a light beam, said light beam of having an original beam divergence and an original coherence radius, and propagating along a beam path;
a beam homogenizer;
a first lens;
a scanning arrangement for scanning said light in beam in a particular pattern over said first lens, such that, averaged over a time less than about the response time of a human eye, said light beam has an effective beam divergence greater than said original divergence thereof, said scanned beam being delivered from said first lens into said beam homogenizer to be homogenized thereby;
a spatial light modulator, said spatial light modulator arranged to receive said scanned light beam homogenized by said beam homogenizer and spatially modulate said homogenized scanned light beam in accordance with a component of an image to be displayed;
a screen for displaying said image;
projection optics for projecting said homogenized scanned light beam onto said screen, said homogenized scanned light beam at said screen having a reduced coherence radius less than said original coherence radius thereof as a result of said scanning thereof, said reduced coherence radius providing a first contribution to minimizing speckle contrast in said image displayed on said screen; and
wherein, said screen includes one or more features for providing a second contribution to minimizing speckle contrast in said image displayed thereon.
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0 Petitions
Accused Products
Abstract
A projection video display includes at least one laser for delivering a light beam. The display includes a beam homogenizer and a condenser lens. A scanning arrangement is provided for scanning the light in beam in a particular pattern over the condenser lens in a manner that effectively increases the beam divergence. The scanned beam is homogenized by a beam homogenizer and a spatial light modulator is arranged to receive the homogenized scanned light beam and spatially modulate the beam in accordance with a component of an image to be displayed. Projection optics are projecting the homogenized scanned light beam onto a screen. The scanning provides that the homogenized scanned light beam at the screen has a coherence radius less than the original coherence radius of the beam. The reduced coherence radius contributes to minimizing speckle contrast in the image displayed on the screen. The screen includes one or more features providing a further contribution to minimizing speckle contrast in the displayed image. In one example, the screen includes a transparent cell containing a liquid having light scattering particles in suspension.
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Citations
40 Claims
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1. A projection display, comprising:
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at least one laser for delivering a light beam, said light beam of having an original beam divergence and an original coherence radius, and propagating along a beam path; a beam homogenizer; a first lens; a scanning arrangement for scanning said light in beam in a particular pattern over said first lens, such that, averaged over a time less than about the response time of a human eye, said light beam has an effective beam divergence greater than said original divergence thereof, said scanned beam being delivered from said first lens into said beam homogenizer to be homogenized thereby; a spatial light modulator, said spatial light modulator arranged to receive said scanned light beam homogenized by said beam homogenizer and spatially modulate said homogenized scanned light beam in accordance with a component of an image to be displayed; a screen for displaying said image; projection optics for projecting said homogenized scanned light beam onto said screen, said homogenized scanned light beam at said screen having a reduced coherence radius less than said original coherence radius thereof as a result of said scanning thereof, said reduced coherence radius providing a first contribution to minimizing speckle contrast in said image displayed on said screen; and wherein, said screen includes one or more features for providing a second contribution to minimizing speckle contrast in said image displayed thereon. - 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, 28, 29, 30, 31)
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32. A projection display, comprising:
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at least one laser for delivering a light beam, said light beam of having an original beam divergence and an original coherence radius, and propagating along a beam path; a beam homogenizer; a first lens; a scanning arrangement for scanning said light in beam in a particular pattern over said first lens, such that, averaged over a time less than about the response time of a human eye, said light beam has an effective beam divergence greater than said original divergence thereof, said scanned beam being delivered from said first lens into said beam homogenizer to be homogenized thereby; a spatial light modulator, said spatial light modulator arranged to receive said scanned light beam homogenized by said beam homogenizer and spatially modulate said homogenized scanned light beam in accordance with a component of an image to be displayed; a screen for displaying said image; projection optics for projecting said homogenized scanned light beam onto said screen, said homogenized scanned light beam at said screen having a reduced coherence radius less than said original coherence radius thereof as a result of said scanning thereof; and wherein, said screen includes a first transparent sheet having a plurality of raised features distributed over a surface thereof, each of said features having a dimension greater than said reduced coherence radius of said light beam, but less than a dimension that would be resolvable by a normal human eye at a normal viewing distance from said screen. - View Dependent Claims (33, 34, 35, 36, 37, 38)
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39. A projection display, comprising:
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at least one laser for delivering a light beam, said light beam of having an original beam divergence and an original coherence radius, and propagating along a beam path; an arrangement for homogenizing said light beam delivered by said laser; a spatial light modulator, said spatial light modulator arranged to receive said homogenized light beam and spatially modulate said homogenized light beam in accordance with a component of an image to be displayed; a screen for displaying said image, said screen includes a transparent cell containing a transparent fluid having particles therein, said particles having a dimension sufficiently small to scatter light and wherein said cell has an RF transducer therein operable for discouraging said particles from coagulating; and projection optics for projecting said homogenized light beam onto said screen.
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40. A screen for a projection display, comprising:
a transparent cell containing a transparent fluid having particles therein, said particles having a dimension sufficiently small to scatter light and wherein said cell has an RF transducer therein operable for discouraging said particles from coagulating.
Specification