| 摘要 |
PURPOSE:To perform accurate tracking of recording and to realize high density of recording, by providing different index sections to correct the shift in tracking a recording part, at each section of the information recording part. CONSTITUTION:Two types of multiplex hatched parts 20 and 21 are located at both sides of an information recording part 19 of a recording carrier 18 as the index parts for tracking shift correction. A beam from a beam source 28 is condensed on the recording part 19 via a half mirror 29 and a head 27a. The reflected beam is introduced to a demodulator 33 via a half mirror 32, a part is converged to a point P of a detection section 5 via a lens 34 and no signal is outputted from detecting elements 36 and 37. If the beam is shifted to the outer or inner side of the recording part 19. Fourier spectrum 41 or 42 due to the multiplex hatched parts 20 and 21 is obtained, a control signal from the element 36 or 37 is applied to terminals 30 and 31 via a switching circuit 38 and control circuits 42 and 43 to accurately trace the recording. Since only one tracking shift correction index is required for each recording section, the density of recording can be achieved. |
