Chromatic confocal displacement measurement system with large range and high linearity
The chromatic confocal displacement measurement system,which has high accuracy and stability and can realize non-contact measurement,has been widely used in many fields such as industry,medical care and scien-tific research.At present,the factors restricting the application and development of chromatic confocal displacement measurement system are large range and high linearity.In this paper,the conditions of realizing linear axial dispersion of dispersive objective lens in a chromatic confocal displacement measurement system are discussed,and a kind of dis-persive objective lens with high linear dispersion and large dispersion range is designed,and the appropriate tolerance range is specified,and a group of dispersive objective lenses are processed and assembled.A chromatic confocal dis-placement measurement system was established,and the displacement was calibrated by a dual-frequency laser inter-ferometer,and the thickness of the standard gauge block was measured.The results show that the working band of the system is 450～650 nm,the range is 10 200 μm,the linear fitting judgment coefficient R2 reaches 0.993 7,and the maximum displacement error of actual measurement is only 3 μm,which proves that the chromatic confocal displace-ment measurement system has the characteristics of large range,high linearity and high measurement accuracy,and has a good application prospect.
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