| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical head device capable of accurately obtaining a tracking error signal even when two or more recording layers are formed in one optical recording disk. <P>SOLUTION: The optical head device 100 for recording/reproducing information in an optical recording disk 1 such as a DVD-R/RW equipped with two or more recording layers 2 (0 layer 20 and 1 layer 21) is provided with a laser emitting element 120 as a light source for emitting a laser beam, and a diffraction element 130 for dividing the laser beam emitted from the laser emitting element 120 into three beams to constitute an optical system. In the case of executing tracking servo by a DPP method, to suppress the amount of a main beam reflected on the 1 layer 21 during recording in the 0 layer 20 to reach the sub photodetecting surface of a photodetecting element 140, the diffraction ratio of a 0-order light, +primary light, and -primary light is set to 8:1:1 to 18:1:1 at a diffraction grating 130. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
