Optical method for precise three-dimensional position measurement
First Claim
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1. A method of measuring three orthogonal coordinates of an object restricted in space to be movable without rotation by a single beam of light comprising:
- providing an interferometer comprising a sensing arm and a probing beam;
affixing a position-sensing photodetector to said object;
using said photodetector as a sensing arm of said interferometer, wherein said probing beam is reflected by a surface of the photodetector;
measuring one of said coordinates interferometrically; and
measuring the remaining said coordinates by measuring electrical signals generated by said photodetector and converting measured signals into coordinates using calculations.
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Abstract
We disclose a method for accurate three-dimensional position measurement in the field of nano-positioning using a single light beam and principles of interferometry to measure position.
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Citations
9 Claims
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1. A method of measuring three orthogonal coordinates of an object restricted in space to be movable without rotation by a single beam of light comprising:
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providing an interferometer comprising a sensing arm and a probing beam; affixing a position-sensing photodetector to said object; using said photodetector as a sensing arm of said interferometer, wherein said probing beam is reflected by a surface of the photodetector; measuring one of said coordinates interferometrically; and measuring the remaining said coordinates by measuring electrical signals generated by said photodetector and converting measured signals into coordinates using calculations. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of determining the coordinates of an object in space along mutually orthogonal x, y and z axes wherein the object is restricted against rotational motion comprising the steps of:
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attaching a position-sensitive photodetector to said object wherein said photodetector has a photodetecting surface parallel to the x-y plane; aiming an interferometric source of coherent light at the photodetector along the z axis; and
measuring the coordinates of the object along three axes, wherein the measurement of the z axis is made interferometrically by reflecting a probing beam from a surface of the photodetector, while the x and y axes are determined by processing signals from the position-sensitive photodetector.
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Specification