| 摘要 |
PURPOSE:To reduce the size and weight of the titled pickup for optical disk by using a means which produces the surface acoustic wave through an optical waveguide to deflect the waveguide light, a tracking error detecting circuit, and a control circuit for a surface acoustic wave generating means respectively. CONSTITUTION:An interdigital transducer IDT 29, for example, is used as a surface acoustic wave generating means. When the frequency of a surface acoustic wave 28 produced by the IDT 29 is changed, the deflecting angle of the waveguide light 24' which is deflected by the surface acoustic wave is changed. Thus the position of the light radiated from a condensing diffraction grating 27 is changed and then the light illuminating position is changed on the surface of an optical disk 40. Therefore the tracking control is possible by changing the frequency of the surface acoustic wave in response to the tracking error signal and then changing the light illuminating position. Furthermore the surface acoustic wave generating means like an IDT, etc. can be set on an optical waveguide 22. Thus a miniaturized pickup for optical disk is obtained. |
