| 摘要 |
<P>PROBLEM TO BE SOLVED: To realize reading of signals recorded in a first optical disk and a second optical disk which are provided with signal recording layers at different positions from the incident surface of a laser beam, by changing the numerical aperture of an objective lens. <P>SOLUTION: This optical pickup device is provided with an aperture restriction element 8 which changes the numerical aperture of the objective lens 7 according to a used optical disk, and a laser optical path control element 4 which is provided within the optical path of the laser beam radiated from a laser diode 1 so as to change the incident angle of the laser beam incident on the objective lens 7. By the numerical aperture changing operation and the incident angle changing operation performed by the aperture restriction element 8 and the laser optical path control element 4, focusing operation to the signal recording layer provided in the respective optical disks is performed. By the drive control operation of a tilt coil 13, coma aberration is corrected. <P>COPYRIGHT: (C)2008,JPO&INPIT |
