| 摘要 |
<P>PROBLEM TO BE SOLVED: To eliminate such a risk that a thick periphery of an objective lens which often brings the objective lens into contact with an optical disk due to shocks or the like, which might break the objective lens and optical disk. <P>SOLUTION: A biconvex optical element made of glass materials includes: a lens having a first optical surface on which a laser beam is incident, and a second optical surface from which the laser beam is emitted; a periphery which is arranged at the periphery of the lens and has a protruded surface protruded at least partially from the second optical surface in the optical axis direction; and a coating film which is formed on the surfaces of the lens and the periphery, whose thickness on the protruded surface is different from that on the surface other than the protruded surface. <P>COPYRIGHT: (C)2011,JPO&INPIT |
