Design of chromatic confocal quantitative inverse dispersive objective lens

Dispersive lens is an important component of chromatic confocal displacement sensor, and the high axial dispersion linearity is the key to its performance. At present, the design of dispersive lens usually adopts multi-configuration to analyze the imaging quality of the image planes at different wavelengths, and the realization is relatively complicated. The design of quantitative inverse dispersive model was introduced, and the multi-configuration that control the axial linear dispersion were implicit in the single configuration, so that the reference plane for image quality evaluation was unified. The design principle of the quantitative inverse dispersive objective lens was explained, and a linear dispersive lens was designed using ZEMAX optical design software. The lens adopted a symmetrical structure about the diaphragm. In the 580-780nm working range, the dispersion range is 0.38mm. The least square method was used to linear fit the axial dispersion and wavelength, and the linear determination coefficient R² is 0.9998. The measured linearity is excellent.