| 摘要 |
<P>PROBLEM TO BE SOLVED: To realize spherical aberration compensations being optimum respectively to a plurality of optical disks formatted differently. <P>SOLUTION: This apparatus is provided with: a first light source 31 emitting a laser beam of a first wavelength; a second light source 32 emitting a laser beam of a second wavelength; an objective lens 33 converging the light beam emitted from the first and the second light sources on a signal recording plane of an optical disk 11; an optical path combining means 34 combining an optical path of the light beams emitted from the first and the second light sources; a liquid crystal optical element 38 adjusting aberration quantity of spherical aberration by changing refractive index; and a photodetector 36 detecting return light. The liquid crystal optical element 38 has a pair of electrodes 53, 54 arranged opposing each other in the direction of the optical axis, and also has a pattern in which at least one side of the electrodes is divided into a plurality of regions. Combination of regions driven by the same condition in accordance with a kind of the optical disk is switched. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
