OPTICAL METHOD FOR PRECISE THREE-DIMENSIONAL POSITION MEASUREMENT

• US 20120113433A1
• Filed: 10/10/2011
• Published: 05/10/2012
• Est. Priority Date: 11/04/2008
• Status: Active Grant

• Current Assignee: Dmitri Simonian, Sergiy Pryadkin
• Original Assignee: Dmitri Simonian, Sergiy Pryadkin
• Inventors: SIMONIAN, Dmitri, PRYADKIN, Sergiy
• Granted Patent: US 8,330,963 B2
• Time in Patent Office: Days
• US Class Current: 356/482
• CPC Class Codes: G01B 11/03 by measuring coordinates of points
• CPC Class Codes: G01B 9/02057 by using common path configuration, i.e. reference and object path almost entirely overlapping
• CPC Class Codes: H02N 2/0055 Supports for driving or driven bodies; Means for pressing driving body against driven body
• CPC Class Codes: H02N 2/025 Inertial sliding motors
• CPC Class Codes: H02N 2/028 along multiple or arbitrary translation directions, e.g. XYZ stages
• CPC Class Codes: Y10T 29/42 Piezoelectric device making

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.

Claims

1. A method of measuring three coordinates of an object in space by a single beam of light comprising:

providing an interferometer comprising a sensing arm;

affixing a position-sensing photodetector to said object;

using said photodetector as a sensing arm of said interferometer;

measuring one of said coordinates interferometrically; and

measuring the remaining said coordinates by measuring electrical signals generated by said photodetector.

2. The method of claim 1 wherein said interferometer is a fiber interferometer, further comprising collimating light emanating from said fiber interferometer with a lens, and directing said light onto said photodetector.

4. The method of claim 1 further comprising providing the accuracy of determination of coordinates of said object in plane of said photodetector between 10 nm and 100 nm for said coordinates disposed within 10 mm from the center of said photodetector.

5. The method of claim 1 wherein said lens is a gradient refractive index lens.

6. The method of claim 1 wherein said position-sensing photodetector is a quadrant photodetector.

7. The method of claim 1 wherein said position-sensing photodetector is a continuous position-sensing light detector operating on the principle of current spreading.

8. The method of claim 2 wherein the lens creating a collimated light is attached to the base of a first positioner in a stack of positioners each having a base and a platform movable on the bases, having a plurality of stages each including a movable platform, and a position-sensing photodetector attached to the moving platform of another positioner in said stack.

9. A method of claim 2 wherein a position-sensing photodetector is attached to the base of a first positioner in a stack of positioners each having a base and a platform movable on the base, and a lens creating collimated light attached to the platform of another positioner of said stack.

3. The method of claim I further comprising providing the accuracy of determination of coordinates of said object in plane of said photodetector between 0.1 nm and 10 nm for said coordinates disposed within 100 μ

m from the center of said photodetector.