OPTICAL RECORDING MEDIUM AND PRODUCTION OF MASTER DISK FOR OPTICAL RECORDING MEDIUM

摘要

PURPOSE:To lower the probability of erroneous recognition of a reproduced signal from the long [it of the optical recording medium by setting the magnitude of the level fluctuation of the reproduced signal waveform from the long bit within 80% center of the normal pulse width of the reproduced signals from the long bit at 1 to 10% of the prescribed reference. CONSTITUTION:A laser beam 13 from a laser beam source 14 is modulated by an EO modulator 15 and the surface of a photoresist layer 12 on a master disk 11 constantly rotating on a spindle 10 is irradiated with the spot of this beam via a condenser lens 21 subjected to focus control by a reflection mirror 13 and a focus control section 20. The master disk for the recording medium and the recording medium are formed in accordance with this master recording disk. The recording medium for the recording system in which the recording regions are zone divided according to radial values and the basic frequencies of the recording information signals changed by each zone has the following characteristics: The magnitude of the level of the reproduced signal waveform from the long bit within central 80% of the normal pulse width of the reproduced signal from the long bit is specified to 51 to 10% of the reference value which is the value obtd. after the magnitude of the average value of the reproduced signal is deducted from the average value of the reproduced signal having no bits at all.