| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical head capable of easily controlling tracking or focusing by a simple structure, an LD module, an optical recording/reproducing device, and an optical element used therefor. <P>SOLUTION: A beam emitted from a light source 1 is divided into main and sub beams by a diffraction element 2. Since the diffraction pattern of the diffraction element 2 has the shape of a sin curve, the spot of the sub beam is larger than that of the main beam. As a result, the sub beam contains almost no track cross component generated by the crossing of the spot on the track of an optical disk 5. Thus, by subtracting the output signal of a detector regarding the sub beam from the push-pull signal of the main beam, a tracking error signal or a focusing error signal substantially containing no DC offset component is obtained. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
