SEEKING ACTION CONTROL SYSTEM

PURPOSE:To complete a seeking action at a position where the changing amount is reduced per unit time of a track owing to the eccentricity of an optical disk, by switching the shift of an optical head to the shift of the light beam radiated from the optical head at the same position on a track of an optical disk medium at all times. CONSTITUTION:A rough seeking control part 1 transmits ''1'' to a flip-flop 3 when an optical head is positioned near a desired track after the rough seeking action is through. Then a pulse shown by a waveform D is supplied from a terminal D every time the index recorded to an optical disk is detected. When a flip-flop 5 is set and a pulse is supplied from the terminal D, a tracking control part 2 starts a fine seeking action to control the optical system of the optical head. Then an optical axis is positioned to the track. The flip-flop 5 is reset when the fine seeking action is over, and at the same time the part 2 gives the follow-up control to the track. The index recorded to the optical disk is recorded at a position where the changing amount is small after checking the eccentricity of the optical disk and therefore can be controlled at the position where the changing amount is always constant.