title: Laser differential confocal radius measurement system.
abstract: A laser differential confocal radius measurement system with high measurement accuracy is developed for optical manufacturing and metrology. The system uses the zero-crossing point of the differential confocal intensity curve to precisely identify the cat's-eye and confocal positions and uses an interferometer to measure the distance between these two positions, thereby achieving a high-precision measurement for the radius of curvature. The coaxial measuring optical path reduces the Abbe error, and the air-bearing slider reduces the motion error. The error analysis indicates the theoretical accuracy of the system is up to 2 ppm, and the experiment shows that the system has high focusing sensitivity and is little affected by environmental fluctuations; the measuring repeatability is between 4 and 12 ppm.
authors.affiliation: Key Laboratory of Photoelectronic Imaging Technology and System, Ministry of Education of China, Opto-Electronic College, Beijing Institute of Technology, China.
authors.forename: Ruoduan
authors.initials: R
authors.lastname: Sun
authors.forename: Lirong
authors.initials: L
authors.lastname: Qiu
authors.forename: Jiamiao
authors.initials: J
authors.lastname: Yang
authors.forename: Weiqian
authors.initials: W
authors.lastname: Zhao