Study on automatic measurement method of elastic modulus for optical glass

In order to solve the problems of long measuring period and complex measurement process of elastic modulus for optical glass, a method of quickly measuring the elastic modulus of small sample optical flat glass by computer image processing technology was proposed. Firstly, based on contact mechanics theory and Newton ring interference principle, the analytical formula for measuring the elastic modulus of optical glass was deduced. Secondly, taking advantage of the image processing technology, the Newton ring interference image was taken by camera, and the interface program of MFC monitoring and single image shooting was designed to automatically measure the center black spot radius of Newton ring interference image. Finally, according to the relationship between the elastic modulus of optical glass, the center black spot radius of Newton ring interference image, and the center stress of Newton ring, the fast measurement of the elastic modulus of small sample optical glass was realized. The experimental results show that the relative error of the elastic modulus for optical glass is no more than ± 8.8% in the range of stress 31.17 N~55.11 N, and ± 16% in the range of stress 55.11 N~71.07 N.