Patent ID: 7800993

Claim:
A recording method of an optical recording medium corresponding to different recording speeds, comprising: irradiating the medium with a laser having m pulse sets each comprising a heating pulse of a power Pw and a cooling pulse of a power Pc, in which m is a natural number; and scanning the medium with the laser at a scanning speed v to record marks each of a length nT on the medium, in which n is a natural number of 3 or more, T is a clock cycle, and the relation of m<n is satisfied, wherein: a length T CPn of a final cooling pulse, which is the m-th cooling pulse, is determined in accordance with the scanning speed v using the following functions (1) and (2), in a range of v<v 0 , T CPn /T=f 1,n ( v ) Function (1) in a range of v≧v 0 , T CPn /T=f 2,n ( v ) Function (2), where the f 1,n (v) and f 2,n (v) each represents a continuous function of the scanning speed v to satisfy the relation of f 1,n (v 0 )>f 2,n (v 0 ); the f 1,n (v) and f 2,n (v) each satisfies the condition where an existence ratio of abnormal marks, which is a ratio of the number of abnormal marks to the number of normal marks, is 1.0×10 −4 or less, the normal mark satisfying the requirement of L/nT≧n−0.5 and the abnormal mark satisfying the requirement of L/nT<n−0.5 where L is a length of each reproduced mark obtained by reproducing the recorded marks; and v 0 is any scanning speed selected to satisfy the existence ratio of the abnormal marks of 1.0×10 −4 or less.