Fig. 1. Determination of the footprints of each field on surface M. (a) The size of the footprint of each field on surface M is approximately determined when the F-number and dz are given. (b) The locations of the footprints for different fields on surface M are also approximately determined based on the EFL, FOV, and the requirement of image-side telecentricity.

Fig. 2. Reverse ray trace from the end of the system to the surface M. The words within the angle brackets represent the functions in the original system.

Fig. 3. Design steps of the starting point for the first design example. (a) Initial system. (b) The system after generating freeform M1 and M2. (c) The system after generating freeform M3. (d) The system after the repeat design process.

Fig. 4. Reverse ray trace from the ideal image points to M3.

Fig. 5. Final design result of the first design example. (a) Optical layout. (b) Distortion grid. (c) MTF plot.

Fig. 6. (a) Initial system of the second design example. (b) The system after the point-by-point design process for the second example.

Fig. 7. Final design result of the second design example. (a) Optical layout. (b) Distortion grid. (c) MTF plot.