Design of Dispersive Module for a 3D Object Shape Detection Device

Confocal line spectroscopy is proposed for obtaining the three-dimensional shape detection of microscopic objects. An off-axis spectral confocal technology composed of TIR lens, PGP beam splitter and cylindrical lens. The design results show that the PGP dispersive device achieves the linearity of dispersion, and the focal plane formed by this scheme has a working distance of 6.92mm on the z-axis, corresponding to the wavelength range of 450nm-700nm, that is, 27.68 $\mu$ m/nm (1nm wavelength is corresponding to 27.68 microns); At the same time, the focal plane is 20mm long and 6.92mm deep, with the one-dimensional movement of the object, the three-dimensional shape information of the object can be obtained.