| 摘要 |
PURPOSE:To facilitate production of an optical disk, by providing an address information hole of a specific depth and at the same time performing a tracking control with a track shift signal and a sector pulse. CONSTITUTION:The address information of an address information region R4 is expressed by the bits A'1-A'n of 1/4lambda (lambda: wavelength of light beam) depth. The reflected light given from a disk D is made incident to a photodetector K, and the address information signal is fed to a sector separating circuit B. Thus a sector pulse is obtained. At the same time, the output of the detector K is detected S for the track of a spot, and a signal of a level corresponding to a degree of track shift is delivered in a scanning period of the same sector from sample holding circuit H. This output signal is fed to a driving circuit W of a rotary mirror M, and the mirror M is turned by an angle corresponding to the degree of the track shift. Thus a light spot is irradiated on a correct track. |
