Patent ID: 6778940
Filing Date: 2004-08-17
Classification: B29C,B29L,G02B

Abstract:
A method of producing an optical element by molding, comprising:a shift measuring step of mounting the optical element molded by injection molding to an optical scanning device, which is equivalent to an optical scanning device to be actually used, and measuring shifts of a focal point in a direction of optical axis at a plurality of image heights on an image surface; a lens height calculating step of calculating positions on a particular optical function surface that correspond one-to-one to the plurality of image heights; a sensitivity calculating step of calculating sensitivity in terms of proportional coefficients of partial curvatures and shifts of the focal point on the particular optical function surface that correspond one-to-one to the plurality of image heights; a partial curvature calculating step of calculating partial curvatures on the particular optical function by using the shifts of the focal point and the sensitivity; a corrected configuration calculating step of outputting, based on the lens heights and the partial curvatures, a corrected configuration of the particular function surface in a form of coefficients of a function model or map data; a correction machining step of machining for correction a specular surface frame of a mold corresponding to the particular optical function surface; and a molding step of molding the optical element by using the specular surface frame corrected.