Design of a line-scanning dispersive objective lens for chromatic confocal displacement sensor

An efficient optimal designing method for a quantitative dispersive objective lens used in line-scanning chromatic confocal displacement sensor was discussed. A multi-configuration optical system consisted of paraxial and diffractive surfaces was proposed to realize the quantitative inverse linear dispersion distance in the wide FOV. The ideal optical model was used as the objective FOV for the design of dispersive lens in the inverse optical path. The multi-configuration with the axial quantitative dispersion was implicit in the single configuration optical path, so that the image plane becomes a unified reference plane for image quality evaluation. With this method, a dispersive objective lens of 580nm-780nm working wavelength band and 0.37 mm axial dispersion distance was designed, which the line-scanning width is 16 mm and the dispersive linearity is better than 0.9997.