FOCUS ADJUSTING METHOD AND APPARATUS FOR LENS INSPECTION SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a focus adjusting method and apparatus capable of calculating and adjusting a focal position with high accuracy without being affected by a difference in the shape of a lens to be inspected. SOLUTION: A lens inspection system comprises a positioning means for controlling the position of the lens to be inspected in all directions; a control means for controlling the positioning means; a light source outputting light of a predetermined wavelength; an objective lens for enlarging a spot image of the light of the light source formed by the lens to be inspected; an eyepiece; an image pickup means for picking up the spot image; an image memory for storing the image picked up by the image pickup means; a computing means for performing computing processes on the image stored in the image memory and for feeding control signals to the control means; and a display means for displaying the image. As the lens to be inspected is moved in the direction of an optical axis by the positioning means, the spot image formed on a plane in a predetermined position is picked up, and the number of pixels which corresponds to a predetermined brightness level or higher is calculated by the computing means so as to adjust a focal position to a position where the number of pixels is at a maximum.