Chromatic confocal sensor with dual dispersion for extending the measuring range

A dual dispersion stitching method is proposed to extend the measuring range of chromatic confocal sensor without reducing the axial resolution. A novel chromatic confocal sensor with dual dispersion is presented and introduced. An X-shaped fiber coupler is employed to divide the light from light source into two beams. These two beams are used to generate two sets of staggered dispersion which extend the measuring range of chromatic confocal sensor. A dual-dispersive objective is designed with Zemax software for verifying the proposed method. The result indicates that the length of total dispersion is extended to 209.6 μm, which is 1.75 times the length of single dispersion. The coefficient of determination between the axial dispersion and wavelength is close to 1.0000.