System and method for measuring the focus state of an optical instrument

摘要

A system and method for measuring the focus state of an optical instrument (eg, a microscope) is disclosed. The system and method form an image of the exit pupil of the objective lens of the optical instrument. One or more optical elements (eg, prisms or mirrors) are placed where the image of the exit pupil is formed, which deflects at least a portion of the light rays coming from the exit pupil, thereby preventing pupil overlap Light rays coming from different parts follow different paths. The light rays coming from the two parts of the pupil are focused and two two-dimensional images are obtained. The computer determines the mutual distance between the two two-dimensional images as a rigid lateral displacement between the two, and based on this distance identifies a corresponding defocus of the optical instrument. [Selection diagram] Fig. 1