Speckle mitigation in laser scanner projector systems
First Claim
1. A laser projection system comprising:
- a visible light source comprising at least one laser;
a system controller programmed to generate a scanned laser image by operating the laser for optical emission of encoded image data and controlling a scanning element to scan an output beam of the visible light source across a plurality of image pixels;
a first lens configured to focus the scanned output beam to form an intermediate laser image;
a second lens configured to project the intermediate laser image onto a projection surface;
a periodic phase mask positioned closer to the intermediate laser image than to the first and second lenses and comprising a period that is approximately equal to or greater than a beam waist diameter of the scanned output beam at the intermediate laser image, wherein the periodic phase mask generates a plurality of orders of diffraction; and
a pupil phase mask comprising a plurality of pixels positioned in an optical path that is after the second lens and configured to modify a relative phase of the orders of diffraction generated by the periodic phase mask,wherein projection of the scanned output beam jumps progressively from pixel to pixel, thereby reducing speckle contrast in a scanned laser image that is projected onto the projection surface.
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Accused Products
Abstract
Laser scanner projection systems that reduce the appearance of speckle in a scanned laser image are provided. The laser projection system includes a visible light source having at least one laser, a scanning element and a system controller. The system controller is programmed to generate a scanned laser image. The system further includes a first lens that focuses a scanned output beam onto an intermediate image and a second lens that projects the intermediate image onto a projection surface. A periodic phase mask having a period that is approximately equal to or greater than the beam waist diameter of the scanned output beam is positioned at the intermediate laser image. The period of the periodic phase mask is such that the projection of the scanned output beam jumps progressively from pixel to pixel, thereby reducing speckle contrast in the scanned laser image.
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Citations
22 Claims
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1. A laser projection system comprising:
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a visible light source comprising at least one laser; a system controller programmed to generate a scanned laser image by operating the laser for optical emission of encoded image data and controlling a scanning element to scan an output beam of the visible light source across a plurality of image pixels; a first lens configured to focus the scanned output beam to form an intermediate laser image; a second lens configured to project the intermediate laser image onto a projection surface; a periodic phase mask positioned closer to the intermediate laser image than to the first and second lenses and comprising a period that is approximately equal to or greater than a beam waist diameter of the scanned output beam at the intermediate laser image, wherein the periodic phase mask generates a plurality of orders of diffraction; and a pupil phase mask comprising a plurality of pixels positioned in an optical path that is after the second lens and configured to modify a relative phase of the orders of diffraction generated by the periodic phase mask, wherein projection of the scanned output beam jumps progressively from pixel to pixel, thereby reducing speckle contrast in a scanned laser image that is projected onto the projection surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A laser projection system comprising:
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a visible light source comprising at least one laser; a system controller programmed to generate an intermediate laser image at an intermediate plane by operating the laser for optical emission of encoded image data and controlling a scanning element to scan an output beam of the visible light source across a plurality of image pixels; and a periodic phase mask positioned at the intermediate plane comprising a period that is approximately equal to or greater than a beam waist diameter of the scanned output beam at the intermediate plane and configured to generate a plurality of orders of diffraction. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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21. A laser projection system comprising:
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a visible light source comprising at least one laser; a system controller programmed to generate an intermediate laser image at an intermediate plane by operating the laser for optical emission of encoded image data and controlling a scanning element to scan an output beam of the visible light source across a plurality of image pixels; and a periodic phase mask positioned at the intermediate plane configured to create a single sub-beam when the scanned output beam is focused on a center portion of an individual period of the periodic phase mask, and create at least two sub-beams when the scanned output beam is focused between at least two periods of the periodic phase mask.
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22. A method of reducing speckle in a projected image of a laser scanner projection system, said method comprising:
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passing a scanning laser beam comprising encoded image data through a first lens that focuses the laser beam to form an intermediate laser image; passing the scanning laser beam comprising the intermediate laser image through a periodic phase mask having a period that is equal to or greater than a beam waist diameter of the scanning laser beam at the intermediate laser image; generating a plurality of orders of diffraction of the scanning laser beam; projecting the intermediate laser image through a second lens and then through a pupil phase mask to form a projected image on a surface, wherein the projected intermediate laser image comprises a projected scanned output beam that jumps progressively from pixel to pixel to reduce speckle contrast in a the projected image.
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Specification