Desensitization design method of a freeform optical system based on local curve control

In this Letter, an error sensitivity evaluation function of freeform optical systems is proposed, and a desensitization design method is established. This method adopts the idea of micro-elements and, based on geometric optics theory, studies the relationship between the local curve of the freeform surface and the change of the wavefront error (ΔWE) when the optical system is disturbed by the position error, and realizes the desensitization design of the optical system. By simply changing the evaluation function, the method can be applied to the desensitization design of any optical system with any surface (spherical, aspheric, and freeform surface).