Chromatic confocal microscope with linear dispersive objective

We built a chromatic confocal microscope for micro metrology. Based on dispersive aberration principle and optimization of lens glasses, a dispersive objective was designed, of which the dispersive aberration was linear to wavelength. The linear dispersive aberration could help to balance the sensitivity of chromatic confocal microscope. Designed dispersive objective is of large dispersive aberration, small longitudinal aberration and long working distance. Influence of system parameters on optical sectioning was analyzed and simulation results were exhibited. Chromatic confocal microscope was built, calibrated and tested. Experimental results show that the measuring range is 1 mm, the resolution is better than 0.5 m and the measuring error in full range is less than 2 m. To test the performance of microscope, profile of standard height was scanned and thickness of transparent plate was measured.