Patent ID: 7977440
Filing Date: 2011-07-12
Classification: C08F,G02B

Abstract:
1. A production method of an objective lens for optical pickup apparatus having numerical aperture NA of image side of 0.80 to 0.90, comprising steps of molding resin composition containing copolymer of α-olefin and a cyclic olefin represented by Formula (I) or (II) to form lens shape, and thermally processing the molded product under a condition at a temperature between Tg −45° C. and Tg −15° C. for 12 to 168 hours, in the formula, n is 0 or 1, m is 0 or a positive integer, and k is 0 or 1, R in the formula (II), p and q independently represent 0 or a positive integer and r and s independently represent 0, 1 or 2, and R