Data input device for tracking and detecting lift-off from a tracking surface by a reflected laser speckle pattern

• US 20050057492A1
• Filed: 08/29/2003
• Published: 03/17/2005
• Est. Priority Date: 08/29/2003
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Bathiche, Steven Nabil, Starkweather, Gary Keith
• Granted Patent: US 7,161,582 B2
• Time in Patent Office: Days
• US Class Current: 345/156
• CPC Class Codes: G06F 3/0304 Detection arrangements using opto-electronic means constructional details of pointing devices not related to the detection arrangement using opto-electronic means G06F3/033; optical digitisers G06F3/042
• CPC Class Codes: G06F 3/0317 in co-operation with a patterned surface, e.g. absolute position or relative movement detection for an optical mouse or pen positioned with respect to a coded surface
• CPC Class Codes: G06F 3/03543 Mice or pucks G06F3/03541 takes precedence
• CPC Class Codes: G06F 3/038 Control and interface arrangements therefor, e.g. drivers or device-embedded control circuitry

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.

Claims

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, said detector having a field of view and operating in a tracking mode when the field of view intersects said coherent light beam striking the tracking surface, the intersection of the coherent light beam and the field of view comprising a detection zone, wherein relative movement within the detection zone 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 zone between said coherent light beam and said tracking surface is not detected; 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 zone.

2. A device as set forth in claim 1 further comprising a housing for the coherent light source and the detector, said housing including a support surface engageable with said tracking surface.

3. A device as set forth in claim 2 wherein said detection zone extends from said housing beyond said support surface to a lift-off detection distance of no more than about 5 millimeters (0.20 inch).

4. A device as set forth in claim 3 wherein said lift-off detection distance is no more than about 4 millimeters (0.16 inch).

5. A device as set forth in claim 4 wherein said lift-off detection distance is no more than about 4 millimeters (0.16 inch) and at least about 1 millimeter (0.04 inch).

6. A device as set forth in claim 5 wherein said lift-off detection distance is no more than about 3 millimeters (0.12 inch) and at least about 1 millimeter (0.04 inch).

7. A device as set forth in claim 6 wherein said lift-off detection distance is no more than about 3 millimeters (0.12 inch) and at least about 1.5 millimeters (0.06 inch).

8. A device as set forth in claim 7 wherein said lift-off detection distance is no more than about 3 millimeters (0.12 inch) and at least about 2 millimeters (0.08 inch).

9. A device as set forth in claim 2 wherein said support surface includes a substantially planar face engageable with said tracking surface.

10. A device as set forth in claim 2 further comprising an optic refracting the coherent light beam into planar waves substantially parallel with the support surface.

11. A device as set forth in claim 1 wherein said coherent light source and said detector are mounted adjacent each other on a microchip.

12. A device as set forth in claim 1 wherein the relative movement outside said detection zone is not detected when said controller determines that reflected, out-of-phase coherent light striking said detector has a total image intensity less than a predetermined threshold intensity.

13. A device as set forth in claim 1 wherein the relative movement outside said detection zone is not detected when said controller determines that reflected, out-of-phase coherent light striking said detector has a signal-to-noise ratio less than a threshold signal-to-noise ratio.

14. A device as set forth in claim 13 wherein said threshold signal-to-noise ratio is 50%.

15. A device as set forth in claim 14 wherein said threshold signal-to-noise ratio is 25%.

16. A device as set forth in claim 15 wherein said threshold signal-to-noise ratio is 10%.

17. A device as set forth in claim 1 wherein the detector includes a field stop defining said field of view of the detector.

18. A device as set forth in claim 17 wherein said detector field stop comprises an aperture in a housing receiving the detector.

19. A device as set forth in claim 17 wherein said detector field stop includes a transparent window of a housing receiving the detector.

20. A device as set forth in claim 1 further comprising an optic defining the field of view of the detector.

21. A device as set forth in claim 20 wherein the optic is integral with the detector.

22. A device as set forth in claim 2 wherein said detector operates in a non-tracking mode and does not detect the relative movement outside said detection zone when said housing at least partially shields reflected out-of-phase, coherent light from striking said detector so that reflected, out-of-phase coherent light striking said detector has a total image intensity less than a predetermined threshold intensity.

23. A device as set forth in claim 1 wherein the coherent light source is a laser.

24. A device as set forth in claim 23 wherein said laser is a vertical cavity surface emitting laser (VCSEL).

25. A device as set forth in claim 1 wherein the coherent light source has a power consumption during operation of less than 1.0 mW (1.3 horsepower).

26. A device as set forth in claim 1 further comprising an optic within the coherent light beam to refract the beam such that the beam divergence is less than 87 milliradians (5 degrees).

27. A device as set forth in claim 26 wherein said beam divergence is less than 70 milliradians (4 degrees).

28. A device as set forth in claim 27 wherein said beam divergence is less than 52 milliradians (3 degrees).

29. A device as set forth in claim 28 wherein said beam divergence is less than or equal to 35 milliradians (2 degrees).

30. A device as set forth in claim 1 wherein the angle between said coherent light beam and a central axis of said field of view is between about 0 milliradians (0 degrees) and about 1.5 radians (85 degrees).

31. A device as set forth in claim 30 wherein the angle between said coherent light beam and a central axis of said field of view is between about 260 milliradians (15 degrees) and about 1.0 radians (60 degrees).

32. A device as set forth in claim 31 wherein the angle between said coherent light beam and a central axis of said field of view is between about 520 milliradians (30 degrees) and about 790 milliradians (45 degrees).

33. A method comprising:

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,

determining if said device is spatially separated from said tracking surface by at least a lift-off detection distance as a function of the detected out-of-phase coherent light, 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 lift-off detection distance 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 lift-off detection distance.

34. A method as set forth in claim 33 further comprising determining if insufficient reflected, out-of-phase coherent light is striking a detector of said device.

35. A method as set forth in claim 34 further comprising defining a field of view of the detector.

36. A method as set forth in claim 34 further comprising shielding said detector from at least a portion of said out-of-phase coherent light reflected by the tracking surface.

37. A method as set forth in claim 33 further comprising detecting that a signal-to-noise ratio of out-of-phase coherent light reflected by the tracking surface and striking said detector is less than a threshold signal-to-noise ratio.

38. A method as set forth in claim 33 wherein said lift-off detection distance is no more than about 4 millimeters (0.16 inch).

39. A method as set forth in claim 38 wherein said lift-off detection distance is no more than about 4 millimeters (0.16 inch) and at least about 1 millimeter (0.04 inch).

40. A method as set forth in claim 39 wherein said lift-off detection distance is no more than about 3 millimeters (0.12 inch) and at least about 1 millimeter (0.04 inch).

41. A method as set forth in claim 40 wherein said lift-off detection distance is no more than about 3 millimeters (0.12 inch) and at least about 1.5 millimeters (0.06 inch).

42. A method as set forth in claim 41 wherein said lift-off detection distance is no more than about 3 millimeters (0.12 inch) and at least about 2 millimeters (0.08 inch).

43. A method as set forth in claim 33 further comprising refracting the coherent light beam into planar waves substantially perpendicular to the propagation of the coherent light beam.

44. 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

a controller responsive to the detector for detecting a change in the total image intensity of the reflected speckle pattern, said change in the total image intensity being related to a distance between the housing and the tracking surface.

45. A device as set forth in claim 44 further comprising a housing for the coherent light source and the detector, said housing including a support surface engageable with said tracking surface.

46. A device as set forth in claim 44 wherein said change in the total image intensity is proportional to the distance between the housing and the tracking surface.

47. A device as set forth in claim 44 wherein said distance between the housing and the tracking surface is no more than about 5 millimeters (0.20 inch).

48. A device as set forth in claim 47 wherein said distance between the housing and the tracking surface is no more than about 4 millimeters (0.16 inch).

49. A device as set forth in claim 48 wherein said distance between the housing and the tracking surface is no more than about 3 millimeters (0.12 inch) and at least about 1 millimeter (0.04 inch).

50. A data input device for suspending tracking of movement with respect to a tracking surface having light-scattering properties, said device comprising:

a source projecting a coherent light beam from said device toward said tracking surface,

a detector detecting the total image intensity of any speckle pattern reflected by said coherent light beam striking said tracking surface, and

a controller determining if said device is spatially separated from said tracking surface by detecting a change in the total image intensity of any reflected speckle pattern, said change in the total image intensity being related to a lift-off detection distance of the housing from the tracking surface, said controller 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 said lift-off detection distance 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 lift-off detection distance.