| 摘要 |
PURPOSE:To eliminate the offset of a differential signal on a light receiving surface, and to improve quality in a track signal, by arranging the positive and the negative codes of the differential signal in both detectors, a semiconductor laser and an optical detector, of an optical head in which they are formed integrally on the same substrate, at the same area. CONSTITUTION:The optical head is constituted by forming a semiconductor laser A and an optical detector B arranged at the bath sides of the laser A integrally on the same substrate. A laser beam 6 is emitted from the emitting terminal 1-1 of the laser A, and after being reflected with a track guide groove 8 on an optical disk, it is changed to reflection diffracted light 9a and 9b, and are received at the receiving planes 1-2 of the detector B, thereby two signals being obtained. In the optical head, the track signal can be obtained with the differential signal of the two signals, and a data signal with a sum signal of them. Since the optical axis 11 of the laser beam 6 is set at the center of an edge part 13 in the guide groove 8, the intensity distribution of the reflection diffracted light is asymmetric to the optical axis 11, however, by arranging the light receiving plane 1-2 at the area of the differential signal having the negative code through an insulation groove, the positive and the negative codes of the differential signal are arranged at the same area. |
