Patent attributes
An information writing device in which the information can be written accurately efficiently and in which variable formats of the disc-shaped recording mediums can be coped with without the necessity of providing master discs from one format of the disc-shaped recording medium to another. A grating interferometer clock scale system is formed by a clock pattern disc 50 having a clock track 52 carrying an optically readable clock pattern 51 and an optical head 60 for optically reading out the clock pattern 51. Clock signals are generated in a clock generator 90, to which is transmitted, via an optical fiber 80, the interference light obtained as an optical output obtained in turn by optically reading out the clock pattern 51 by the optical head 60, based on electrical signals obtained on photoelectrically transducing the optical output. The servo information synchronized with the clock signals is generated by a servo information generating part 93.
