Fig. 1. Dual focal plane freeform prism optical system with single PGU, TN, and PRF

Fig. 2. Driving waveform of TN liquid crystal and corresponding polarized light output

Fig. 3. Schematic diagram of structural constraint

Fig. 4. Initial structure of large field of view freeform prism

Fig. 5. Examples of dual focal plane system optimization. (a) Freeform prism after zoom; (b) short-focus system structure; (c) long-focus system structure; (d) combination structure; (e) combination structure with the addition of polarizing device; (f) final dual focal plane prism structure

Fig. 6. Full field of view modulation transfer function. (a) MTF curves for the short-focus system; (b) MTF curves for the long-focus system

Fig. 7. Full field grid distortion diagrams. (a) Distortion diagram of the short-focus system; (b) distortion diagram of the long-focus system

Fig. 8. Imaging effect simulation of the dual focal plane system. (a) Simulation diagram of the short-focus system; (b) simulation diagram of the long-focus system

Fig. 9. Stray light analysis outside the field of view for short-focus system. (a) Stray light simulation diagram; (b) schematic diagram of single line of light tracing

Fig. 10. Illuminance distribution diagrams of the receiving surface in the field of view of short-focus system. (a) Stray light distribution diagrams in the field of view; (b) simulation diagrams of the improved system

Fig. 11. Stray light analysis outside the field of view for long-focus system: (a) Stray light simulation diagram; (b) schematic diagram of single line of light tracing

Fig. 12. Illuminance distribution diagrams on the receiving surface in the field of view for long-focus system. (a) Stray light distribution diagrams in the field of view; (b) simulation diagrams of the improved system