Laser despeckler based on angular diversity
First Claim
1. An illumination device comprising:
- a first transparent substrate having an output surface;
a variable refractive index layer having an input surface and an output surface,wherein said input surface of said refractive index layer overlayssaid output surface of said first transparent substrate;
a second transparent substrate having an input surface, wherein said input surface of said second transparent layer overlays said output layer of said variable refractive index layer; and
a holographic diffuser,wherein said output surface of said variable refractive index layer and said input layer of said second transparent substrate are each configured as a multiplicity of ray deflecting features to deflect incident light into a temporally varying random distribution of ray directions in a first predefined range of angles having a plurality of angles of deflection such that the plurality of angles of deflection are varied as a voltage applied across the variable refractive index is iteratively varied,wherein each point in said holographic diffuser diffracts incident light rays of said first predefined range of angles into output light rays having a second predefined range of angles such that a diffuse illumination patch is produced at any surface intercepting said output light rays.
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Abstract
A device for reducing laser speckle using a micro scanner and a holographic diffuser. The micro scanner includes a first transparent optical substrate with an input surface and an output surface and a second transparent optical substrate with an input surface and an output surface and a variable refractive index medium sandwiched between the output surface of the first substrate and the input surface of the second substrate. Transparent electrodes are applied to the output surface of the first substrate and the input surface of the second substrate. The electrodes are coupled to a voltage generator. The input surface of the first substrate is optically coupled to a laser source. The input surface of the second substrate is configured as an array of prismatic elements. At least one of the input surface of the first substrate or the output surfaces of the second substrate is planar.
818 Citations
22 Claims
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1. An illumination device comprising:
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a first transparent substrate having an output surface; a variable refractive index layer having an input surface and an output surface, wherein said input surface of said refractive index layer overlays said output surface of said first transparent substrate; a second transparent substrate having an input surface, wherein said input surface of said second transparent layer overlays said output layer of said variable refractive index layer; and a holographic diffuser, wherein said output surface of said variable refractive index layer and said input layer of said second transparent substrate are each configured as a multiplicity of ray deflecting features to deflect incident light into a temporally varying random distribution of ray directions in a first predefined range of angles having a plurality of angles of deflection such that the plurality of angles of deflection are varied as a voltage applied across the variable refractive index is iteratively varied, wherein each point in said holographic diffuser diffracts incident light rays of said first predefined range of angles into output light rays having a second predefined range of angles such that a diffuse illumination patch is produced at any surface intercepting said output light rays. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification