Patent ID: 7609603

Claim:
A recording method for a rewritable optical recording medium, which comprises: recording information on a rewritable optical recording medium by a plurality of record mark lengths and space lengths between record marks based on runlength limited (RLL) non-return-to-zero inverted (NRZI) modulation system; irradiating, between record marks, a laser beam having an erasing power Pe capable of crystallizing an amorphous phase to form spaces between record marks; when a time length of one record mark is represented by nT (where T is a reference clock period), for a record mark of n=2m (where m is an integer of at least 1), a time length (n−j)T (where j is a real number from −2.0 to 2.0) of the n=2m record mark is divided into m sections of α i T and β i T comprising α 1 T, β 1 T, α 2 T, β 2 T, . . . , α m T and β m T (provided that Σ i (α i +β i )=n−j), and for a record mark of n=2m+1 (where m is an integer of at least 1), a time length (n−k)T (where k is a real number from −2.0 to 2.0) of the n=2m+1 record mark is divided into m sections of α i ′T and β i ′T comprising α 1 ′T, β 1 ′T, α 2 ′T, β 2 ′T, . . . , α m ′T and β m ′T (provided that Σ i (α i ′+β i ′)=n−k), applying a laser beam having a constant writing power Pw sufficient to melt a recording layer within a time of α i T and α i ′T (where i is an integer from 1 to m); applying a laser beam having a bias power Pb within a time of β i T and β i ′T (where i is an integer from 1 to m); and further, when m≧3, for a record mark of n=2m, when a start time for an nT mark is represented by T 0 , (i) generating α 1 T after a delay time T d1 T from T 0 , then, (ii) alternately generating within i=2 to m, β i−1 T and α i T in this order, while β i−1 +α i is between 1.8 and 2.2 (provided that at i=2 and/or i=m, β i−1 +α i may be deviated from about 2 within a range of ±0.5, and when m≧4, β i−1 and α i take constant values βc and αc, respectively, within i=3 to m−1), and then, (iii) generating β m T, and for a record mark of n=2m+1, when a start time for an nT mark is represented by T 0 , (i) generating α 1 ′T after a delay time T d1 ′T from T 0 , then, (ii) alternately generating within i=2 to m, β i−1 ′T and α i ′T in this order, while β i−1 ′+α i ′ is between 1.8 and 2.2 (provided that at i=2 and/or i=m, β i−1 ′+α i ′ may be deviated from about 2 within a range of ±2, and when m≧4, β i−1 ′ and α i ′ take constant values βc and αc, respectively, within i=3 to m−1), and then, (iii) generating β m ′T, and with the same m, for a record mark of n=2m and a record mark of n=2m+1, T d1 =T d1 ′, α 1 =α 1 ′, β 1 =β 1 ′ and α m ≠α m ′, and at least one set selected from (β m−1 and β m−1 ′) and (β m and β m ′) takes different values.