| 摘要 |
<P>PROBLEM TO BE SOLVED: To form an objective lens of plastic in order to improve productivity and weight reduction, and achieve the compensation of coma aberration even if an environment temperature is changed. <P>SOLUTION: Disclosed is the objective lens 34 formed of plastic which is used for an optical pickup 3 for recording and reproducing an optical disk, wherein a tertiary order coma aberration quantity caused when the objective lens is tilted satisfies a prescribed relational expression where a distance in the thickness direction from the zeroth layer to nth layer being the maximum cover layer thickness is used as a parameter. <P>COPYRIGHT: (C)2010,JPO&INPIT |
