| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical pickup device in which a laser beam can be appropriately made incident even on an objective lens of a small effective diameter while a lens element consisting of a convex lens and a concave lens is used as an aberration correction lens, and in addition, the simplification of an optical system and the facilitation of assembly work are achieved. <P>SOLUTION: A collimator lens 103 is arranged in a position parting more from a semiconductor laser 101 than a polarization beam splitter 102, behind which the convex lens 104a is arranged. By displacing the concave lens 104b, the spherical aberration on a BD recording surface is suppressed. The beam diameter after the beam is passed through the concave lens 104b can be made smaller than the beam diameter when the beam makes incidence on the convex lens 104a. The laser beam can be appropriately made incident even on the objective lens 108 of the small diameter. Also, the effective diameter of the collimator lens 103 can be made greater and therefore, the adjustment work of the collimator lens 103 during assembly can be easier. <P>COPYRIGHT: (C)2008,JPO&INPIT |
