Optical design of zoom structured light imaging system

In order to change the focal length of optical system rapidly and at a low cost, we designed the zoom structured light three-dimensional imaging lens and micro-lens array based on liquid lens.The system utilizes the structure of seven spherical glass lenses and one liquid lens, the F# number is 3.2, the full field of view(FOV) is 10 mm, the system total length is 180 mm, and the focal length ranges from 54 mm to 61 mm. The design result shows that, the system can adjust the distance of projection in 227 mm~256 mm; during focusing process the target surface is clear and the resolution ratio has a high quality, while system is within the whole zoom range; at 40 lp/mm, the modulation transfer function(MTF) of full FOV is better than 0.2, the system field curvature is less than 0.2, and the distortion is less than 0.2%.The cylindrical micro-lens array has an overall size of 10 mm×10 mm, a period width of 1 mm and a thickness of 1 mm. With the increase of projection distance, the imaging quality of optical system increases first and then decreases, the imaging quality is optimal at 237 mm; as the projection distance increases, the magnification of the optical system increases; the overall relative illuminance heterogeneity of optical system is less than 0.2.