JPS6423424A - Double-sided recording type optical disk and its recording and reproducing method - Google Patents

Abstract

PURPOSE:To simultaneously attain an access both front and rear sides in parallel by manufacturing a disk in a form adhering a disk base material of the same constitution onto the front and rear sides. CONSTITUTION:A disk base material with a sector identifier pre-formatted to a part sectioning a track into plural sectors is manufactured. An address signal in the middle and synchronizing signals S1, S2 at both sides before and after the address signal are arranged symmetrically to identify the sector. The disk base material is adhered onto the front and rear sides to form a double- sided recording disk. Two optical heads H1, H2 are provided and the H1, H2 system is synchronized by synchronizing signals S1, S2 to reproduce an address signal. Then the reproduced output from the head H1 or H2 is given to a clock recovery circuit 1, from which a clock (CK) signal and a data signal are extracted. The data signal becomes a right or left shift input to a shift register 4 via an AND gate 2 or 3 and shifted by the CK signal. When the front/rear signal is 1 or 0, the data signal is given to the gates 2, 3 as a right or left shift input and an address signal is a correct direction is outputted to a processing circuit 5.