Design of a wide-field wavelength-coded depth-sensing objective

In this work, we develop a wide-field wavelength-encoded depth-sensing objective. Specifically, the depth can be perceived by color conversion algorithms or decoded by the peak wavelength of on-focus light. By extending both the field of view (FOV) and the focal shift to millimeter scale, further combining either a 2D mechanical scan or a point-source array, 3D surface data can be efficiently acquired. The optical design is optimized based on a dual-telecentric six-lens configuration, aiming at large-range, highly linear axial chromatic aberration, and uniform imaging across a wide field. Ultimately, under the working band of 420-700 nm, the objective achieved a 5.27 mm focal shift with a linearity of <i>R</i>²=0.99, exhibiting uniform imaging quality within a 16×16<i>m</i><i>m</i>² FOV. The structural design was carefully considered for manufacturing tolerances before processing and assembly. The experiment showed that the objective achieved a lateral resolution of 3.10 µm at the central wavelength.