Diffractive waveguide providing structured illumination for object detection
First Claim
1. Apparatus for projecting an image onto a surface comprising:
- a first light source emitting light of a first wavelength;
first and second multiplicities of separately switchable grating elements;
transparent substrates sandwiching said grating elements providing a first light guide; and
a means for coupling said first wavelength light into a total internal reflection path in said first light guide,each said grating element having a diffracting state and a non-diffracting state, wherein each element of said first multiplicity of grating elements when in its diffracting state diffracts said first wavelength light to form a focused first image region of predefined geometry and luminance distribution on said image surface,wherein each element of said first multiplicity of grating elements encodes wave-front amplitude and phase information corresponding to said geometry and luminance distribution,wherein each said element of said second multiplicity of grating elements provides a first unique speckle state under a first applied voltage and a second unique speckle state under a second applied voltage.
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Accused Products
Abstract
A projection display device comprising a light source and an SBG device having a multiplicity of separate SBG elements sandwiched between transparent substrates to which transparent electrodes have been applied. The substrates function as a light guide. A least one transparent electrode comprises a plurality of independently switchable transparent electrode elements, each electrode element substantially overlaying a unique SBG element. Each SBG element encodes image information to be projected on an image surface. Light coupled into the light guide undergoes total internal reflection until diffracted out to the light guide by an activated SBG element. The SBG diffracts light out of the light guide to form an image region on an image surface when subjected to an applied voltage via said transparent electrodes.
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Citations
20 Claims
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1. Apparatus for projecting an image onto a surface comprising:
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a first light source emitting light of a first wavelength; first and second multiplicities of separately switchable grating elements; transparent substrates sandwiching said grating elements providing a first light guide; and a means for coupling said first wavelength light into a total internal reflection path in said first light guide, each said grating element having a diffracting state and a non-diffracting state, wherein each element of said first multiplicity of grating elements when in its diffracting state diffracts said first wavelength light to form a focused first image region of predefined geometry and luminance distribution on said image surface, wherein each element of said first multiplicity of grating elements encodes wave-front amplitude and phase information corresponding to said geometry and luminance distribution, wherein each said element of said second multiplicity of grating elements provides a first unique speckle state under a first applied voltage and a second unique speckle state under a second applied voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification