US 11,714,055 B2
Method for laser stimulated lock-in thermography for micro-crack detection
Lu Ding, Singapore (SG); and Jinghua Teng, Singapore (SG)
Assigned to AGENCY FOR SCIENCE, TECHNOLOGY AND RESEARCH, Singapore (SG)
Filed by AGENCY FOR SCIENCE, TECHNOLOGY AND RESEARCH, Singapore (SG)
Filed on Jun. 16, 2022, as Appl. No. 17/842,391.
Application 17/842,391 is a division of application No. 16/498,814, granted, now 11,397,158, previously published as PCT/SG2018/050159, filed on Mar. 29, 2018.
Claims priority of application No. 10201702564S (SG), filed on Mar. 29, 2017.
Prior Publication US 2022/0307999 A1, Sep. 29, 2022
Int. Cl. G01N 25/72 (2006.01); G01N 21/84 (2006.01); G01N 21/88 (2006.01); G01N 21/71 (2006.01); G01N 21/63 (2006.01)
CPC G01N 25/72 (2013.01) [G01N 21/63 (2013.01); G01N 21/71 (2013.01); G01N 21/84 (2013.01); G01N 21/88 (2013.01); G01N 21/8851 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A method for laser stimulated lock-in thermography (LLT) crack detection in a system capable of switching between a plurality of LLT configurations on a sample, wherein the plurality of LLT configurations comprise a plurality of spot LLT laser beam focus configurations and at least one line LLT laser beam focus configuration, the method comprising:
using a first one of the plurality of LLT configurations for coarse scanning of the sample to detect a crack, hole or scratch on the sample; and
when a crack, hole or scratch is detected on the sample, switching to a second one of the plurality of LLT configurations for fine scanning of the crack, hole or scratch on the sample to determine one or more parameters of the crack, hole or scratch on the sample, wherein the first one of the plurality of LLT configurations comprises one of the at least one line LLT laser beam focus configurations.