| 摘要 |
PURPOSE:To eliminate the complicated alignment of an optical axis and to miniaturize and lighten an optical disk by controlling the relative position of a semiconductor laser and a thin film wave guide so that an optical spot is converged with following the surface deflection of the optical disk. CONSTITUTION:The semiconductor laser 11 being an optical source is movably fitted, and the position of the semiconductor laser 1 is controlled in accordance with forcusing error and tracking error signals. Namely, a negative voltage is added to an actuator 17a, and a positive voltage to an actuator 17b, if the tracking error signal is positive, whereby an actuator 16 is displaced and the outgoing angle of the semiconductor laser becomes +DELTAtheta. On the other hand, the positive voltage is added to the actuator 17a, and the negative voltage to the actuator 17b, if the tracking error signal is negative, whereby the actuator 16 is dislocated and the outgoing angle of the semiconductor laser becomes -DELTAtheta. Consequently, a spot position on the disk surface is controlled in the direction of a radius, and a beam spot is irradiated on the disk surface with following track fluctuation due to the off center disk. Thus, the complicated adjustment of the optical axis is eliminated.
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