Modulation of laser power in accordance with a linear velocity by pulse division schemes

In an optical recording process for recording data in or erasing data from an optical information recording medium through a formation or erasure of optically distinguishable amorphous marks by irradiating laser radiation having laser power modulated by at least three levels in accordance with a clock period T, said process including the steps of:

• providing a linear velocity V ranging between V.sub.L and V.sub.h on an optical recording medium, said clock period T being varied in accordance with said linear velocity V;
• irradiating with a focussed laser beam to record a mark having an nT mark length on the optical recording media in an mark-length modulation recording;
• and
• modulating the laser radiation to have m individual pulses each having a recording power level Pw and a pulse duration .alpha..sub.i T, with an interval .beta..sub.i T provided between corresponding two of said pulse durations for providing a bias power level Pb.sub.i, the i representing integers 1 to m, whereby obtaining a time sequence of .alpha..sub.1 T, .beta..sub.1 T, .alpha..sub.2 T, .beta..sub.2 T, . . . .alpha..sub.m T and .beta..sub.m T for the laser power,
• the improvement wherein said recording process includes the step of changing at least one of a combination of .alpha..sub.i T's and Pb.sub.i in accordance with the linear velocity V on condition that the following inequality and equalities are satisfied:
• n.sub.min -k.gtoreq.1;
• m=n-k;
• and
• .alpha..sub.1 +.beta..sub.1 + . . . +.alpha..sub.m +.beta..sub.m =n-j,
• wherein k and j represent an integer which satisfies 0.ltoreq.k .ltoreq.2 and a real number which satisfies 0.ltoreq.j.ltoreq.2, respectively, and wherein n.sub.min represents a minimum value of the n.