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 having light-scattering properties with respect to said device, 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;
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;
a field stop and an optic configured for defining a field of view and an expanded field of view of the detector, wherein the detector operates in a tracking mode when either the field of view or the expanded field of view, or both, intersects said coherent light beam striking the tracking surface, the intersection of the coherent light beam and the field of view comprising a primary detection zone extending from the device to a primary lift-off detection distance and the intersection of the coherent light beam and the expanded field of view comprising a secondary detection zone extending from the device to a secondary lift-off detection distance,said field stop being further configured for reducing the size of the primary detection zone and the secondary detection zone by blocking all of the reflected speckle pattern from reaching the detector when the tracking surface is outside the detection zones to reduce the primary lift-off detection distance and the secondary lift-off detection distance, wherein relative movement within the detection zones between said coherent light beam and said tracking surface is detected in the tracking mode based on the reflected speckle pattern, and wherein relative movement outside the detection zones between said coherent light beam and said tracking surface is not detected due to the field stop blocking all of the reflected speckle pattern from reaching the detector, thereby providing lift-off detection near the device for suspending tracking upon movement of the tracking surface and the device apart from one another greater than the primary lift-off detection distance and the secondary lift-off detection distance; and
a controller responsive to the detector operating in the tracking mode for correlating the imaged laser speckle pattern to track the relative movement within the detection zones.
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Accused Products
Abstract
A data input device for use with a tracking surface having light-scattering properties. The device comprises a coherent light source for projecting a coherent light beam onto the tracking surface to reflect a speckle pattern. A detector having a field of view detects and images the speckle pattern. The detector operates in a tracking mode when the field of view intersects the coherent light beam. The intersection of the coherent light beam and the field of view comprise a detection zone. Relative movement between the coherent light beam and the tracking surface within the detection zone between is detected in the tracking mode, based on the reflected speckle pattern. Relative movement between the coherent light beam and the tracking surface outside the detection zone is not detected. A controller responsive to the detector operates in the tracking mode for correlating the imaged laser speckle pattern to track the relative movement within the detection zone.
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Citations
34 Claims
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1. A data input device for use with a tracking surface, said tracking surface having light-scattering properties with respect to said device, 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; 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; a field stop and an optic configured for defining a field of view and an expanded field of view of the detector, wherein the detector operates in a tracking mode when either the field of view or the expanded field of view, or both, intersects said coherent light beam striking the tracking surface, the intersection of the coherent light beam and the field of view comprising a primary detection zone extending from the device to a primary lift-off detection distance and the intersection of the coherent light beam and the expanded field of view comprising a secondary detection zone extending from the device to a secondary lift-off detection distance, said field stop being further configured for reducing the size of the primary detection zone and the secondary detection zone by blocking all of the reflected speckle pattern from reaching the detector when the tracking surface is outside the detection zones to reduce the primary lift-off detection distance and the secondary lift-off detection distance, wherein relative movement within the detection zones between said coherent light beam and said tracking surface is detected in the tracking mode based on the reflected speckle pattern, and wherein relative movement outside the detection zones between said coherent light beam and said tracking surface is not detected due to the field stop blocking all of the reflected speckle pattern from reaching the detector, thereby providing lift-off detection near the device for suspending tracking upon movement of the tracking surface and the device apart from one another greater than the primary lift-off detection distance and the secondary lift-off detection distance; and a controller responsive to the detector operating in the tracking mode for correlating the imaged laser speckle pattern to track the relative movement within the detection zones. - 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)
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26. A method comprising:
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projecting a coherent light beam from a data input device onto a diffuse tracking surface, detecting out-of-phase coherent light reflected by the tracking surface with a detector, controlling the amount of out-of-phase coherent light reflected by the tracking surface reaching the detector, said controlling comprising, defining a field of view of the detector, the intersection of the projected coherent light beam and the field of view comprising a primary detection zone extending from the device to a primary lift-off detection distance, defining an expanded field of view of the detector, the intersection of the projected coherent light beam and the expanded field of view comprising a secondary detection zone extending from the device to a secondary lift-off detection distance, and reducing the size of the primary detection zone and the secondary detection zone and reducing the primary lift-off detection distance and the secondary lift-off detection distance, determining if said device is spatially separated from said tracking surface by at least the primary and secondary lift-off detection distances as a function of the detected out-of-phase coherent light, thereby providing lift-off detection near the device, and either suspending tracking of relative movement between said device and said tracking surface when said device is spatially separated from said tracking surface by at least the primary and secondary lift-off detection distances by blocking all of the out-of-phase coherent light reflected by the tracking surface from reaching the detector, or maintaining tracking of relative movement between said device and said tracking surface when said device is spatially separated from said tracking surface by less than said primary and secondary lift-off detection distances by allowing at least a portion of the out-of-phase coherent light reflected by the tracking surface to reach the detector. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34)
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Specification