A mathematical model of Schmidt corrector plate with defocus in variable for quick F ratio and large aperture systems

To make it easier for designing Schmidt optical systems, based on wavefront aberration functions, a mathematical model of the corrector plate aspheric surfaces varies as a function of defocusing amount is established. It corrects not only the third-order spherical aberration, but also the 5th-order spherical aberration for the system. A series of Schmidt optical systems were designed as examples to evaluate the mathematical model of the aspherics. Results show that the mathematical model is precisely in fitting the needed shape of the corrector, and can be used for the systems for quick F ratio and large aperture. A mathematical model for reflective correctors shape is also established.