Patent ID: 7898933

Claim:
An optical disc, comprising tracks, each divided into a plurality of recording blocks; wherein: each of the plurality of blocks includes a run-in area and a data area; in the run-in area, a prescribed run-in bit pattern is recordable; in the data area, bit patterns having a plurality of bit lengths obtained by modulating data as a recording target in accordance with a prescribed modulation rule are recordable; where the shortest mark among the bit patterns having the plurality of bit lengths has a length of TM nm, the shortest space among the bit patterns having the plurality of bit lengths has a length of TS nm, laser light used for irradiating the track has a wavelength of 2 nm, and an objective lens for collecting the laser light has a numerical aperture NA, TM+TS<λ/(2×NA) is fulfilled; and the run-in bit pattern recordable in the run-in area includes the bit patterns having the plurality of bit lengths, from which a bit pattern having a bit length equal to or shorter than λ/(2×NA)/2 has been excluded.