The deformation measurement of active lap before being used to polish the mirror is one of the key factors that restrict the mirror’s quality. Usually micro displacement sensors are used to measure the deformation. The sensors are located on a square grid or a circle array, but different arrangements of sensor array bring different accuracies. Which arrangement is the best for the measuring is unknown at present. A method of calculating the best arrangement of the sensor array is put forward. Firstly, Zernike polynomial is used to represent and reconstruct the lap surface, meanwhile, the variables concerned such as the number of sensor circles and the sensor number of each circle are shown. Secondly, we choose the RMS of measurement error as the standard to judge whether an arrangement is better or worse. Thirdly, Genetic Algorithm is widely used in optimization, especially in the optimization with a lot of variables. Here using the Genetic Algorithm we can successfully achieve a better arrangement of the sensors after some generations’ evolution. The result shows that using the optimized arrangement can improve the measurement accuracy. Examples shown can prove the theory is correct.

Date Published: 16 October 2012
PDF: 5 pages
Proc. SPIE 8416, 6th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Advanced Optical Manufacturing Technologies, 84161Y (16 October 2012); doi: 10.1117/12.974278

Published in SPIE Proceedings Vol. 8416:
6th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Advanced Optical Manufacturing Technologies
Li Yang; Eric Ruch; Shengyi Li, Editor(s)