Optical translation measurement
First Claim
1. A method for determining the relative motion of a surface with respect to a measurement device comprising:
- illuminating the surface from a source with incident illumination, such that illumination is diffusely reflected from portions of the surface towards a detector;
spatially filtering the diffusely reflected illumination such that the phase of the detected optical illumination from a given scatterer on the surface is substantially constant or linearly related to the translation of the surface;
generating a signal by the detector responsive to the illumination incident on the detector; and
determining the relative motion of the surface in a direction parallel to the surface from the signal;
wherein illuminating the surface comprises illuminating the surface through a partially reflecting object placed adjacent to the surface which object reflects or diffracts illumination to the detector.
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Accused Products
Abstract
A method for determining the relative motion of a surface with respect to a measurement device comprising:
illuminating the surface from a source with incident illumination, such that illumination is reflected from portions of the surface toward a detector;
spatially filtering the reflected illumination such that the phase of the detected optical illumination from a given scatterer on the surface is substantially constant or linearly related to the translation of the surface;
generating a signal by the detector responsive to the illumination incident on the detector; and
determining the relative motion of the surface from the signal.
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Citations
34 Claims
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1. A method for determining the relative motion of a surface with respect to a measurement device comprising:
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illuminating the surface from a source with incident illumination, such that illumination is diffusely reflected from portions of the surface towards a detector;
spatially filtering the diffusely reflected illumination such that the phase of the detected optical illumination from a given scatterer on the surface is substantially constant or linearly related to the translation of the surface;
generating a signal by the detector responsive to the illumination incident on the detector; and
determining the relative motion of the surface in a direction parallel to the surface from the signal;
wherein illuminating the surface comprises illuminating the surface through a partially reflecting object placed adjacent to the surface which object reflects or diffracts illumination to the detector. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 21, 25, 26, 27, 28, 29, 30)
the illumination of the surface is substantially collimated; and
includingspatially filtering the illumination reflected from the surface such that substantially only a single spatial frequency of the reflected illumination is detected by the detector.
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6. A method according to claim 1 wherein:
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illumination of the surface is substantially collimated; and
includingspatially filtering the illumination reflected from the surface such that only illumination reflected from the surface substantially in a single direction is detected by the detector.
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7. A method according to claim 1, wherein spatially filtering comprises:
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focusing the illumination reflected from the surface with a lens having a focal point; and
placing a pinhole at the focal point of the lens.
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8. A method according to claim 1, wherein spatially filtering comprises:
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focusing the illumination reflected from the surface with a lens having a focal point; and
placing a single mode optical fiber at the focal point of the lens to transfer illumination to the detector.
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9. A method according to claim 1, wherein spatially filtering comprises:
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focusing the illumination reflected from the surface with a lens; and
placing a pinhole at an image of the source.
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10. A method according to claim 1, wherein spatially filtering comprises:
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focusing the illumination reflected from the surface with a lens; and
placing a single mode optical fiber at an image of the source to transfer illumination to the detector.
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11. A method according to claim 1 wherein determining the relative motion comprises determining the relative motion in two directions parallel to the surface.
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12. A method according to claim 1 wherein determining the relative motion comprises detecting the sense of the direction of the relative motion.
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13. A method according to claim 1 wherein determining the motion comprises counting zero-crossings of the signal.
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14. A method according to claim 1 wherein illuminating the surface comprises illuminating the surface through a partially diffracting object placed adjacent to the surface which diffracts illumination to the detector.
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15. A method according to claim 1 wherein the object is a grating.
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16. A method according to claim 14 wherein the object is a grating.
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21. A method according to any of claims 1, 11 or 17 and including determining the relative motion in a direction perpendicular to the surface.
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25. A method according any of claims 1, 17 or 23 wherein the illumination is perpendicularly incident on the surface.
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26. A method according to any of claims 1, 17 or 23 wherein the surface is optically diffusely reflecting surface.
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27. A method according to any of claims 1, 17 or 23 wherein the surface has no markings indicating position.
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28. A method according to any of claims 1, 17 or 23 wherein the illumination comprises visible illumination.
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29. A method according to any of claims 1, 17 or 23 wherein the illumination comprises infra-red illumination.
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30. An optical mouse comprising:
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a housing having an aperture facing a surface; and
an optical motion detector which views the surface through the aperture, wherein the optical motion detector utilizes the method of any of claims 1, 17 or 23 to determine the translation of the housing with respect to the surface.
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17. A method for determining the relative motion of a surface with respect to a measurement device comprising:
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illuminating the surface with illumination through a partially transmitting object that is not attached to the surface and is operative to cause spatial variation of the illumination on the surface, such that said illumination is reflected from the surface to illuminate a detector with diffusely reflected illumination which is not an image of a point on or a portion of the surface;
simultaneously illuminating the detector with reference illumination derived from said incident illumination;
coherently detecting the reflected illumination received by the detector utilizing said reference illumination such that the detector generates a signal;
determining the relative motion of the surface parallel to the surface, based on variations of the signal with time. - View Dependent Claims (18, 19, 20, 22)
illuminating the surface through a transmission grating having spatially varying periodic transmission.
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20. A method according to claim 17 wherein spatially varying the illumination of the surface comprises:
illuminating the surface through a grating which specularly reflects a portion of the illumination incident upon it toward the detector to form said reference illumination.
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22. A method according to claim 17 wherein the object is a partially reflecting object and wherein illumination reflected or diffracted from the object provides a local oscillator field for said coherent detection.
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23. A method for determining the relative motion of a surface with respect to a measurement device comprising:
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illuminating the surface with illumination having a coherence length, such that illumination is reflected from portions of the surface;
placing a grating within the coherence length from the surface;
coherently detecting diffusely reflected illumination reflected from the surface, and utilizing illumination reflected from or diffracted by the grating as a local oscillator to form a signal; and
determining the relative motion of the surface, in a direction parallel to the surface, from a characteristic of the signal. - View Dependent Claims (24)
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31. A method for determining the relative motion of a surface with respect to a measurement device comprising:
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illuminating the surface from a source, with spatially varying incident illumination, such that a portion of the illumination is diffusely reflected from portions of the surface towards a detector;
spatially filtering the diffusely reflected illumination such that only illumination reflected from the surface substantially in a single direction is detected by the detector;
generating a signal by the detector responsive to the illumination incident on the detector; and
determining the relative motion of the surface in a direction parallel to the surface from the signal, responsive to a characteristic of the spatial variation. - View Dependent Claims (32, 33, 34)
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Specification