| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a tracking servo control device which adjusts spacing between beams by using a rotatable diffraction lens so as to perform tracking servos by DVD-ROM and DVD-RAM methods differing in track pitch, and to provide a control method therefor. <P>SOLUTION: The tracking servo control device comprises; a light source, a diffraction grating for diffracting incident light and splitting it into three pieces, a rotation means for rotating the diffraction grating, an objective lens, an incident light path conversion means located between the light source and the objective lens, a collimator lens located between the light path conversion means and the objective lens, a detector of which the arrival area of a main beam is divided into four pieces and the arrival area of each auxiliary beam is divided into two pieces, and the tracking control means which discriminates the kind of disks and rotates the diffraction grating by controlling the rotation means if the disk is DVD-RAM. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
