Laser differential confocal interference multi-parameter comprehensive measurement method and its system for spherical lens

Different measurement methods have been used to achieve different parameter measurements of a spherical lens, and multi-parameter measurements of a spherical lens have low measurement accuracy and efficiency. This paper proposes a new, laser differential confocal interference multi-parameter measurement (DCIMPM) method for spherical lens. Based on this proposed DCIMPM, a multi-parameter comprehensive measurement system is developed for spherical lens, which uses the laser differential confocal parameter measurement technique to measure the radius of curvature, thickness, and refractivity of spherical lens, and uses the laser interference measurement technique to measure the surface figure of a spherical lens. Therefore, the DCIMPM system, for the first time, achieves high-accuracy multi-parameter comprehensive measurements of a spherical lens on a single instrument. Experiments indicate that the developed DCIMPM system can achieve a measurement accuracy of 5 × 10^-6 for the lens radius, 2.5 × 10^-4 for the lens thickness, 2.2 × 10^-4 for the lens refractivity, and a peak to valley of λ/20 for the surface figure of the lens. The proposed DCIMPM principle and developed system provide a new approach to achieve multi-parameter comprehensive measurements for spherical lens.