US 7,321,421 B2
Apparatus and methods for scanning conoscopic holography measurements
Stephen J. Bennison, Bellevue, Wash. (US)
Assigned to The Boeing Company, Chicago, Ill. (US)
Filed on Jul. 30, 2004, as Appl. No. 10/903,332.
Prior Publication US 2006/0023223 A1, Feb. 02, 2006
Int. Cl. G01N 21/00 (2006.01)
U.S. Cl. 356—237.1  [356/237.6; 356/445; 356/614] 33 Claims
OG exemplary drawing
 
1. A system for performing a measurement of a physical characteristic of a workpiece, comprising:
a conoscopic holography sensor configured to emit a laser beam;
a beam directing assembly configured to adjustably direct the laser beam toward the workpiece, and to adjustably direct a reflected light from the workpiece into the conoscopic holography sensor, wherein the conoscopic holography sensor includes a crystal configured to transmit the reflected light to form a fringe pattern at least partially indicative of the physical characteristic, wherein the beam directing assembly includes:
a first mirror operatively coupled to a first galvanometer and being controllably adjustable to direct the laser beam alone a first axis; and
a second mirror operatively coupled to a second galvanometer and being controllably adjustable to direct the laser beam along a second axis; and
a control assembly operatively coupled to the conoscopic holography sensor and to the beam directing assembly, the control assembly being configured to send a first control signal to the conoscopic holography sensor to initiate the emission of the laser beam, and a second control signal to the beam directing assembly to controllably adjust a direction of the laser beam.