Data input device for tracking and detecting lift-off from a tracking surface by a reflected laser speckle pattern
First Claim
1. A data input device for use with a tracking surface, said tracking surface being optically rough, said device comprising:
- a coherent light source for projecting a coherent light beam onto said tracking surface to reflect a speckle pattern from the coherent light beam striking said tracking surface;
an optic positioned in the coherent light beam for altering a wavefront profile of the coherent light beam so that the coherent light beam has a substantially constant phase relative to a plane perpendicular to said beam at a tracking distance from said optic, said tracking distance being different than a focal length of the optic, whereby said tracking surface reflects a substantially stable speckle pattern from the altered coherent light beam when the coherent light source and tracking surface are separated by about said tracking distance, wherein said optic alters the wavefront profile of said coherent light beam so that the coherent light beam is substantially out-of-phase across the coherent light beam within a plane perpendicular to said beam at an out-of-phase distance from said optic, such that locating the tracking surface at about said out-of-phase distance from said optic creates a boiling speckle pattern;
a detector associated with the coherent light source for detecting said speckle pattern reflected by the tracking surface and for imaging the detected speckle pattern; and
a controller responsive to the detector for correlating the speckle pattern either to track relative movement between the coherent light beam and the tracking surface when the detector detects said substantially stable speckle pattern or to suspend tracking of relative movement between the coherent light beam and the tracking surface when the detector detects said boiling speckle pattern.
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Accused Products
Abstract
A data input device for use with an optically rough tracking surface comprising a coherent light source projecting a coherent light beam and an optic positioned in the coherent light beam. The optic alters a wavefront profile of the coherent light beam so that the coherent light beam has a substantially constant phase relative to a plane perpendicular to the beam at a tracking distance from the optic. The coherent light beam is projected onto the tracking surface to reflect a substantially stable speckle pattern. A controller responsive to a detector correlates the substantially stable speckle pattern to track relative movement between the coherent light beam and the tracking surface. The controller suspends tracking of relative movement between the coherent light beam and the tracking surface when the detector detects a boiling speckle pattern.
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Citations
51 Claims
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1. A data input device for use with a tracking surface, said tracking surface being optically rough, said device comprising:
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a coherent light source for projecting a coherent light beam onto said tracking surface to reflect a speckle pattern from the coherent light beam striking said tracking surface; an optic positioned in the coherent light beam for altering a wavefront profile of the coherent light beam so that the coherent light beam has a substantially constant phase relative to a plane perpendicular to said beam at a tracking distance from said optic, said tracking distance being different than a focal length of the optic, whereby said tracking surface reflects a substantially stable speckle pattern from the altered coherent light beam when the coherent light source and tracking surface are separated by about said tracking distance, wherein said optic alters the wavefront profile of said coherent light beam so that the coherent light beam is substantially out-of-phase across the coherent light beam within a plane perpendicular to said beam at an out-of-phase distance from said optic, such that locating the tracking surface at about said out-of-phase distance from said optic creates a boiling speckle pattern; a detector associated with the coherent light source for detecting said speckle pattern reflected by the tracking surface and for imaging the detected speckle pattern; and a controller responsive to the detector for correlating the speckle pattern either to track relative movement between the coherent light beam and the tracking surface when the detector detects said substantially stable speckle pattern or to suspend tracking of relative movement between the coherent light beam and the tracking surface when the detector detects said boiling speckle pattern. - 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, 32, 33, 34, 35)
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36. A data input device for use with a tracking surface, said tracking surface being optically rough, said device comprising:
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a coherent light source for projecting a coherent light beam onto said tracking surface to reflect a speckle pattern from the coherent light beam striking said tracking surface; and an optic positioned in the coherent light beam for altering a wavefront profile of the coherent light beam so that the coherent light beam has a substantially constant phase relative to a plane perpendicular to said beam at a tracking distance from said optic, said tracking distance being different than a focal length of the optic, whereby said tracking surface reflects a substantially stable speckle pattern of speckle grains from the altered coherent light beam when the coherent light source and tracking surface are separated by about said tracking distance, wherein said optic alters the wavefront profile of said coherent light beam so that the coherent light beam is substantially out-of-phase across the coherent light beam within a plane perpendicular to said beam at an out-of-phase distance from said optic about equal to the focal length of the optic, such that locating the tracking surface at about said focal point of said optic creates speckle grains that are on average too large to track relative to an illumination area of the coherent laser beam and such that locating the tracking surface at about said out-of-phase distance from said optic at about said focal length of the optic creates a boiling speckle pattern. - View Dependent Claims (37, 38, 39)
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40. A data input device for use with a tracking surface, said tracking surface being optically rough, said device comprising:
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a coherent light source for projecting a coherent light beam onto said tracking surface to reflect a speckle pattern from said coherent light beam striking said tracking surface; and an optic positioned in the coherent light beam for altering a wavefront profile of said coherent light beam to create a detection zone between about 35% and about 90% of the focal length of the optic, wherein relative movement within the detection zone between said coherent light beam and said tracking surface is detected based on the reflected speckle pattern, and a lift-off zone beyond about 90% of the focal length of the optic, wherein relative movement within the lift-off zone between said coherent light beam and said tracking surface is not detected, wherein the speckle pattern comprises speckle grains, such that locating the tracking surface at about said focal length of said optic creates speckle grains that are on average too large to track relative to an illumination area of the coherent laser beam. - View Dependent Claims (41, 42, 43, 44, 45, 46, 47, 48)
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49. A data input device for suspending tracking of movement comprising:
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a source projecting a coherent light beam onto an optically rough tracking surface, an optic focusing the coherent light beam, said optic altering the wavefront profile of said coherent light beam such that the coherent light beam has a substantially constant phase across at least one plane perpendicular to the coherent light beam, a detector detecting out-of-phase coherent light reflected from the tracking surface as a speckle pattern, and a controller determining if said data input device is spatially separated from said tracking surface by at least a lift-off detection distance as a function of whether the average width of the speckle grains of the speckle pattern are too large to track, said controller suspending tracking of relative movement between said data input device and said tracking surface when said data input device is spatially separated from said tracking surface by at least the lift-off detection distance. - View Dependent Claims (50, 51)
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Specification