US 10,890,431 B2
MEMS tunable VCSEL powered swept source OCT for 3D metrology applications
James Jiang, Hackettstown, NJ (US); and Alex Cable, Newton, NJ (US)
Assigned to Thorlabs, Inc., Newton, NJ (US)
Filed by Thorlabs, Inc., Newton, NJ (US)
Filed on Dec. 10, 2019, as Appl. No. 16/709,494.
Application 16/709,494 is a division of application No. 15/469,036, filed on Mar. 24, 2017, granted, now 10,557,701.
Claims priority of provisional application 62/313,346, filed on Mar. 25, 2016.
Prior Publication US 2020/0109938 A1, Apr. 9, 2020
Int. Cl. G01B 9/02 (2006.01); G01B 11/00 (2006.01); G01B 11/24 (2006.01); G01B 11/06 (2006.01); H01S 5/022 (2006.01); H01S 5/065 (2006.01); H01S 5/10 (2006.01); H01S 5/183 (2006.01)
CPC G01B 11/005 (2013.01) [G01B 9/02004 (2013.01); G01B 9/02044 (2013.01); G01B 9/02091 (2013.01); G01B 11/007 (2013.01); G01B 11/0608 (2013.01); G01B 11/2441 (2013.01); H01S 5/02284 (2013.01); H01S 5/0651 (2013.01); H01S 5/1042 (2013.01); H01S 5/183 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A coordinate measurement machine comprising:
a surface configured to hold an object to be measured;
a measurement probe configured to move to a known spatial coordinates near the object by a moving mechanism, the measurement probe having re-configurable optics inside;
an optical stylus generated by the reconfigurable optics inside the measurement probe, wherein the optical stylus:
has an adjustable diameter and length;
has an adjustable distance from the optical stylus center to the probe; and
is in optical contact with the object;
an optical coherence tomography (OCT) system configured to measure an optical delay difference between the light from the object and a reference light from a reference position using an optical interference method, to determine a height of the object;
a first control loop configured to control the distance from the optical stylus center to the probe using the object height measured by the OCT system, causing the optical stylus in optical contact with the object; and
a second control loop configured to control the reference position of the reference light, using the object height measured by the OCT system, to change an electronic frequency of the optical interference signals to be within an optimal detection range of the OCT system, and for the OCT system to process the optimized interference fringe signals to determine the height of the object with improved accuracy.