JPS6459633A - Recorder for optical information - Google Patents

Abstract

PURPOSE:To form pits at a uniform size at all times by varying the recording layer quantity in response to the interval of a recording pulse so as to correct the distortion due to the heat of a pit diameter. CONSTITUTION:DFFs 5a, 5b retard a recording signal 4s by clock periods T, 2T and a NAND gate 5c detects a recording pulse whose pulse interval is T. Similarly, DFFs 5a, 5b and a NAND gate 5d detects consecutive pulse and an output 5ds is at 'L'. The recording signal 4s is inputted to a laser drive circuit 7 and an AND signal 6 as being the signals 4s, 5ds is given to the circuit 8, which is stopped only at the consecutive pulse. An AND signal 6bs among the signals 4s, 5ds and 5cs is given to the 3rd laser drive circuit 9, which is stopped in case of consecutive pulse and with a pulse interval T. The drive current of the laser diode 3a is the sum of currents 7i-9i given to the laser drive circuits 7-9. With a short pulse interval, the current to the element 3a is small, the radiated luminous quantity is reduced to correct the heat dissipation by the recording light just before, the peak temperature is made constant and a pit with equal size is formed to the film at all times.