Numerical Iterative Design and Analysis of Double Freeform Surface Telecentric F-Theta Lens.

As one of the most important optical components of a laser scanning system, the f-theta lens group largely determines the working range and scanning accuracy of this system. In this paper, a numerical iterative design method of a double freeform surface telecentric f-theta lens is proposed. Then the scanning linearity and optical transmittance of the designed f-theta lens are simulated and analyzed. The results show that the f-theta lens designed by this method has a compact structure, large scanning area, extremely high optical transmittance over the entire field of view, and stable, controllable error of scanning linearity. Different from the optimization design method of the traditional f-theta lens group, the two freeform surfaces of this f-theta lens can be obtained directly and simultaneously by using this numerical iterative method, which consumes less computational resources and significantly reduces the design complexity.