Novel parallel measurement method of spectral confocal sensor with multi-point scanning

Abstract

Spectral confocal technology has widespread applications in the field of surface topography measurement. However, conventional spectral confocal sensors are limited to acquiring height information for one point at a time during the measurement process. Consequently, the need for point-by-point scanning compromises the efficiency of existing methodologies. To address this challenge, we propose a novel measurement method utilizing a Nipkow disk and spectral imaging technology. This innovative approach enables simultaneous acquisition of height information for multiple points. In this paper, a dispersive objective lens is designed by using Zemax OpticStudio optical design software, specifically tailored for simultaneous multi-point measurements. The dispersive lens group consists of five single lenses and one double cemented lens, working within the wavelength range of 450nm to 720nm. The dispersion range can reach 450μm, with a dispersion linearity coefficient of 0.998. The accuracy of the dispersive objective lens for multi-point measurement is validated through non-sequential mode simulations in Zemax OpticStudio. The results demonstrate a measurement linearity of 0.998 for each individual measurement point. This simulation experiment provides theoretical foundations and guidance for subsequent experimental endeavors.