Automatic compact-volume design strategy for unobscured reflective optical systems based on conicoid surfaces

Off-axis reflective optical systems are frequently large in volume to avoid obscuration, and their subsequent optimizations are complex and time-consuming, resulting in volume reduction while sacrificing surface shape complexity. Therefore, this paper proposes an automatic small-volume high-resolution reflective optical system design strategy based on joint aberration model and a global simulated annealing algorithm (SA). The method establishes a comprehensive joint aberration-based imaging quality and volume-constrained evaluation function. Under the premise of ensuring the imaging quality, the volume reduction of two off-axis three-mirror reflective optical systems with large fields of view (FOVs) has been achieved greatly: (1) the volume of the systems with off-axis FOVs was compressed to 22.7% of the conventional method; (2) the volume of the systems with a small F-number, decenter and tilt was compressed to 28.3% of the conventional method, successfully achieving the volume compression of the off-axis reflective optical systems, proving the feasibility and simplicity of this method. This method is more scalable, starting with a conical surface, which can well realize the transition from simple to complex surfaces, providing the choice and comparison of surface types and contributing to the rapid estimation of the system volume.