Abstract

A laser confocal radius measurement (LCRM) method is proposed for high-accuracy measurement of the radius of curvature (ROC). The LCRM uses the peak points of confocal response curves to identify the cat eye and confocal positions precisely. It then accurately measures the distance between these two positions to determine the ROC. The LCRM also uses conic fitting, which significantly enhances measurement accuracy by restraining the influences of environmental disturbance and system noise on the measurement results. The experimental results indicate that LCRM has a relative expanded uncertainty of less than 10 ppm for both convex and concave spheres. Thus, LCRM is a feasible method for ROC measurements with high accuracy and concise structures.

© 2014 Optical Society of America

Laser differential confocal radius measurement

Weiqian Zhao, Ruoduan Sun, Lirong Qiu, and Dingguo Sha
Opt. Express 18(3) 2345-2360 (2010)

Laser differential confocal radius measurement system

Ruoduan Sun, Lirong Qiu, Jiamiao Yang, and Weiqian Zhao
Appl. Opt. 51(26) 6275-6281 (2012)

Laser reflection differential confocal large-radius measurement

Weiqian Zhao, Xin Zhang, Yun Wang, and Lirong Qiu
Appl. Opt. 54(31) 9308-9314 (2015)

Error analysis for a laser differential confocal radius measurement system

Xu Wang, Lirong Qiu, Weiqian Zhao, Yang Xiao, and Zhongyu Wang
Appl. Opt. 54(5) 1078-1084 (2015)

Laser confocal radius measurement method for unpolished spheres

Xu Wang, Weiqian Zhao, Lirong Qiu, Shuai Yang, and Zhongyu Wang
Appl. Opt. 55(17) 4558-4563 (2016)