光谱共焦位移传感器具有精度高、适应性强等特点，传感器的关键部件是产生轴向色散的物镜。本文对传感器的工作原理进行了分析，推导了计算物镜光学参数的公式，并依据此公式计算结果设计物镜，得到了满足设计指标的物镜，且与理论计算相符。传感器的工作波长范围是500~700 nm，设计的色散物镜利用高色散玻璃和双胶合透镜达到了1 mm 的量程，配以合适的光谱仪，传感器分辨率优于1 μm。物镜使用齐明透镜和双胶合透镜减小球差，使得各波长的最大球差约为0.6 μm，满足物镜精度要求。

Chromatic Confocal Displacement Sensor (CCDS) is now used widely for its high precise and robust property. As the key component, the objective is used to achieve longitudinal focus vibration with wavelength. The theory of CCDS is analyzed and formulae for calculating the parameters of objective are presented. With the formulae guiding, a dispersive objective was designed. To obtain large axial aberration, the objective is configured with high dispersive glass singlet and special doublet lens. And aplanatic lenses and doublet are used to reduce longitudinal aberration. The objective dispersed the focus of wavelength between 500~700 nm to 1 mm longitudinal range, and the longitudinal aberration is less than 0.6 μm. With selected spectrometer, the resolution of CCDS is no more than 1 μm, which meets the requirements of dispersive objective precision.