| 摘要 |
<P>PROBLEM TO BE SOLVED: To prepare an optical element made of plastics provided with highly accurate optical characteristics and to provide an optical pickup device having satisfactory pickup characteristics. <P>SOLUTION: The optical element made of plastics comprises a resin composition containing an alicyclic hydrocarbon based copolymer having ≥90mass% content of recurring units (a) having an alicyclic structure represented by general formula (1) and recurring units (b) having a chain structure represented by general formula (2), general formula (3) or general formula (4) and 1 to 10mass% content of the recurring units (b) in all the recurring units of the polymer having weight average molecular weight (Mw) of 1,000 to 1,000,000 and an antioxidant represented by general formula (I) and having 20 to 60 g/10 min melt index at 260°C with 2.16 kg load and is used for the optical pickup device performing reproduction and recording of information in an optical information recording medium having an optical path difference imparting structure imparting optical path difference to light passing through one optical surface on one optical surface. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
