Fanned laser beam metrology system

• US 7,450,251 B2
• Filed: 11/09/2005
• Issued: 11/11/2008
• Est. Priority Date: 11/09/2005
• Status: Expired due to Fees

• Current Assignee: The Boeing Co.
• Original Assignee: The Boeing Co.
• Inventors: Liu, Ketao, Guthrie, Richard W., Bender, Douglas, Lundgren, Mark A., Liu, John Y., Sedivec, Peter J., Becker, Gregory S.
• Primary Examiner(s): Lauchman; L. G.
• Assistant Examiner(s): BRYANT, REBECCA CAROLE
• Application Number:
  US11/270,000
• Publication Number:
  US 20070103698A1
• Time in Patent Office: 1,098 Days
• Field of Search: 356/614, 356/620, 356/621, 356/622, 356/375, 356/4.01, 356/5.01, 356/3.09
• US Class Current: 356/625
• CPC Class Codes: G01B 11/14 for measuring distance or clearance between spaced objects or spaced apertures G01B11/26 takes precedence; rangefinders G01C3/00
• CPC Class Codes: G01S 17/48 Active triangulation systems, i.e. using the transmission and reflection of electromagnetic waves other than radio waves

Abstract

Systems and techniques for laser metrology. A system may include a laser source and a fanning apparatus configured to generate a fanned laser beam. The fanned laser beam may be scanned across the surface of an object, and may reflect off a plurality of targets positioned on the surface. A position detection module may determine a position of the metrology targets based on the reflected beam.

Claims

1. A metrology system comprising:

a laser source;

a fanning apparatus to receive light from the laser source and to generate a fanned transmitted beam, the beam being fanned across a first angular range;

a scanner configured to scan the fanned transmitted beam through an second angular range so as to generate a scanned fanned transmitted beam, wherein at least one metrology target is positioned on a first surface of an object within the first and second angular ranges so as to form a reflected beam; and

a position detection module configured to receive the reflected beam and to determine, with respect to a reference point, a range to the at least one metrology target, a first angle within the first angular range for the at least one metrology target, and a second angle within the second angular range for the at least one metrology target, the position detection module using the range, the first angle, and the second angle to determine a position of the at least one metrology target based on the reflected beam.

2. The metrology system of claim 1, wherein the fanning apparatus comprises at least one of a lens and a holographic grating.

3. The metrology system of claim 2, wherein the fanning apparatus comprises a cylindrical lens.

4. The metrology system of claim 1, wherein the first angular range is an elevation angular range, the first angle thereby being an elevation angle, and wherein the position detection module includes a substantially linear sensor to determine the elevation angle.

5. The metrology system of claim 4, wherein the substantially linear sensor is a one-dimensional charge coupled device (CCD).

6. The metrology system of claim 4, wherein the substantially linear sensor is a one-dimensional position sensing detector (PSD).

7. The metrology system of claim 1, wherein the second angular range is an azimuth angular range, the second angle thereby being an azimuth angle, and wherein scanner includes an angular measurement sensor to sense the azimuth angle.

8. A method of determining a plurality of positions on a surface, comprising:

generating a laser beam fanned through a first angular range to provide a fanned laser beam;

scanning the fanned laser beam through a second angular range so as to scan the fanned laser beam across the surface;

sensing a first angle within the first angular range through receipt of a return beam reflected from a first target at a first position of the plurality of positions;

sensing a second angle within the second angular range through the receipt of the return beam;

determining a range of the first target through the receipt of the return beam; and

determining the first position based on the range, the first angle, and the second angle.

9. The method of claim 8, wherein the second angular range is an azimuth angular range, the second angle thereby being an azimuth angle.

10. The method of claim 8, wherein the first angular range is an elevation angular range, the first angle thereby being an elevation angle, and wherein the sensing of the elevation angle is determined through a substantially one-dimensional sensor.

11. The method of claim 8, wherein determining the range of the first position comprises determining a time between a beam generation pulse and receiving the return beam.

12. The method of claim 8, wherein determining the range of the first position comprises determining a phase relationship between the probe beam and the return beam.

13. A metrology system comprising:

a light source module configured to generate a substantially two dimensional probe beam, the probe beam extending in a first direction and fanning across a first angular range;

a scanner configured to scan the probe beam through a second angular range to scan across a surface in a second direction different than the first direction, the surface including a plurality of reflective targets;

a substantially one dimensional sensor positioned and configured to receive return beams from the plurality of reflective targets, and wherein the one dimensional sensor is configured to sense first angles within the first angular range to the reflective targets;

a sensor configured to sense second angles within the second angular range to the reflective targets; and

a position detection module configured to determine ranges to the reflective targets, the position detection module using the ranges, the first angle, and the second angles to determine a deformation of the surface.

14. The system of claim 13, wherein the first angular range is an elevation angular range, the first angles thereby being elevation.

15. The system of claim 14, wherein the second angular range is an azimuth angular range, the second angles thereby being azimuth angles.

16. The system of claim 13, wherein the position detection module includes a correlation module in communication with the light source module.

17. The system of claim 13, wherein the position detection module includes processing electronics in communication with the one dimensional sensor.

18. The system of claim 13, wherein the system is a space metrology system.