| 摘要 |
<P>PROBLEM TO BE SOLVED: To attain miniaturization of a device by shortening a total track length in an optical characteristic maintaining state. <P>SOLUTION: In an optical pickup provided with a divergent angle converting lens 4 converting a divergent angle of a light beam made incident as a divergent light beam and emitting the resultant light beam and an objective lens 5 in which the light beam whose divergent angle is converted by the divergent angle converting lens is made incident and which converges and emits the light beam and can be displaced in a tracking direction, a spherical aberration corresponding to the amount by which an astigmatic aberration generated when the objective lens is displaced can be canceled is imparted to the divergent angle converting lens 4 and a spherical aberration which can cancel the spherical aberration imparted to the divergent angle converting lens and a coma aberration which can cancel a coma aberration generated by spherical aberration imparted to the divergent angle converting lens when the objective lens is displaced are imparted to the objective lens 5. <P>COPYRIGHT: (C)2008,JPO&INPIT |
