| 摘要 |
PROBLEM TO BE SOLVED: To enable an optical medium which contains dyestuff in its recording layer to perform satisfactory high density recording that comprises formation of pits, each having a smaller diameter than the laser spot diameter. SOLUTION: This recording medium is provided on a transparent substrate with a recording layer and a metallic reflection layer. In this recording method, mark edge recording is performed in such a way that the correlation of the minimum pit length Pmin with (r) ((r) is λ/NA (where λ is a recording wavelength (μm) and NA is the numerical aperture of a pickup objective lens)) meets the relation 0.35r<=Pmin<=0.45r, and when laser beam irradiation for forming a pit of length of Mi[T] (Mi[T] is the length of a pit (i); represented with a clock cycle T as units, (i) is a positive integer, and M1<M2<...<Mi<...<Mn), while placing a space of Lj[T] between the pit (i) and its preceding pit (where Lj[T] is the length of the space, represented with by clock time T as the unit, (j) is a positive integer, and L1<L 2<...<Lj<...<Lm), is performed in such a way as to meet the following relation ti(L1)<ti(L 2)<=...<=ti(Lj)<=...<=ti(Lm), and when an irradiation time ti[T] is ti(Lj) (where ti[T] is the irradiation time for forming the pit (i), represented with the clock cycle T as units, and ti(Lj) is ti[T] at the placing of the space of Lj[T] between the pit (i) and its preceding pit); and 0.01T<=Δtij<=0.2T (when Δtij=ti(Lj)-ti(L1), and (Js) for all with j>=2. |
