Three-dimensional profile measurement for lens by full-field interferometry

A method for measuring the three-dimensional (3D) profile of lens by full-field interferometry was proposed to meet the requirement of high accuracy processing technology. A distribution feedback(DFB)diode laser of calibrated 3D profile measurement system was used to perform the wavenumber-scanning interferometric measurement for the lens. The interference image random sampling Fourier transform(RSFT) and unwrapping algorithm were used to process interference image acquired by CCD, and finally the 3D lens profile was obtained after had been calculated. Experimental results indicate that the horizontal and vertical resolution of the system are both 0.011 3 mm / pixels, and the root mean square error of measurement in the depth direction is ±19.8 nm. The system is characterized by simple structure, high stability, no contact with the lens, no damage to the lens surface, and high-precision contour measurement suitable for the lens.