| 摘要 |
PURPOSE:To provide an optical head device capable of reducing track-jumping and stably reproducing information. CONSTITUTION:By transferring a reproducing signal including astigmatic aberration to the detecting surface 34a of a detector 34 by means of a collimator lens 18 and an ellipse compensating element 20 arranged between a polarizing beam splitter 16 and a galvano-mirror 22 and separating a diffracted component caused by the track of an optical disk from a laser beam for tracking on the detecting surface 34b of the detector 34 by means of a holographic element 32, exact tracking control is performed. By introducing a part of the output of a laser 12 to a monitoring detector 36 by means of the half mirror 20a of the ellipse compensating element 20, the control of emitting light quantity at high-speed is attained. Furthermore, by suppressing the fluctuated amount of a laser beam corresponding to the angular deviation of the galvano-mirror 22, exact tracking is performed. |
