Image projection screen with reduced speckle noise
First Claim
Patent Images
1. An arrangement for projecting an image with reduced speckle noise, comprising:
- a) a display screen having front and rear surfaces, and an array of lenslets;
b) an image projection assembly for directing a laser beam on the rear surface of the screen, and for sweeping the beam as a pattern of scan lines across the rear surface of the screen, each scan line extending along a scan direction and having a number of pixels, and for causing selected pixels to be illuminated, and rendered visible, to produce the image, the laser beam having a beam dimension along the scan direction; and
c) means for reducing speckle noise by configuring each lenslet to have a lenslet dimension, as measured along the scan direction, which is not less than said beam dimension.
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Abstract
An image projection module within a housing is operative for causing selected pixels in a raster pattern to be illuminated to produce an image on a display screen of VGA quality. The screen is provided with an array of lenslets to reduce speckle noise in the image.
25 Citations
18 Claims
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1. An arrangement for projecting an image with reduced speckle noise, comprising:
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a) a display screen having front and rear surfaces, and an array of lenslets; b) an image projection assembly for directing a laser beam on the rear surface of the screen, and for sweeping the beam as a pattern of scan lines across the rear surface of the screen, each scan line extending along a scan direction and having a number of pixels, and for causing selected pixels to be illuminated, and rendered visible, to produce the image, the laser beam having a beam dimension along the scan direction; and c) means for reducing speckle noise by configuring each lenslet to have a lenslet dimension, as measured along the scan direction, which is not less than said beam dimension. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of projecting an image with reduced speckle noise, comprising the steps of:
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a) emitting a laser beam; b) directing the beam to be incident on a rear surface of a display screen, and sweeping the beam as a pattern of scan lines across the rear surface of the screen, each scan line extending along a scan direction and having a number of pixels, and causing selected pixels to be illuminated, and rendered visible, to produce the image, the laser beam having a beam dimension along the scan direction; and c) forming the screen with an array of lenslets, and configuring each lenslet to have a lenslet dimension, as considered along the scan direction, which is not less than said beam dimension, thereby reducing speckle noise. - View Dependent Claims (10, 11, 12, 13, 14)
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15. A display screen for reducing speckle noise in an image projected by a laser beam on the screen, comprising:
- an array of lenslets arranged in succession along a scan direction, each lenslet having a lenslet dimension, as measured along the scan direction, which is not less than a beam dimension, again as measured along the scan direction, of the laser beam.
- View Dependent Claims (16, 17)
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18. An arrangement for projecting an image with reduced speckle noise, comprising:
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a) a display screen having front and rear surfaces, and an array of lenslets successively arranged along a scan direction; b) an image projection assembly for directing a laser beam on the rear surface of the screen, and for sweeping the beam as a pattern of scan lines across the rear surface of the screen, each scan line extending along the scan direction and having a number of pixels, and for causing selected pixels to be illuminated, and rendered visible, to produce the image; and c) a polarization rotating coating on alternate lenslets for reducing speckle noise.
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Specification