OPTICAL DISC AND OPTICAL DISC RECORDING/REPRODUCTION METHOD Russian patent published in 2013 - IPC G11B7/07 

FIELD: information technology.

SUBSTANCE: optical disc has tracks, each of which is divided into recording blocks. Each of the blocks includes an input area and a data area. A given input bit pattern can be recorded in the input area. Bit patterns having a plurality of bit lengths obtained by modulating data as a recording target in accordance with a given modulation rule can be recorded in the data area. The shortest mark among the bit patterns, having said plurality of bit lengths, has a length TM nm. The shortest space among the bit patterns has a length of TS nm. Laser light used for irradiating the track has a wavelength of λ nm. An objective lens for collecting the laser light has a numerical aperture NA, TM+TS<λ/(2×NA) is fulfilled. The input bit pattern recordable in the input area includes bit patterns having said plurality of bit lengths, from which a bit pattern having a bit length equal to or shorter than λ/(2×NA)/2 is excluded.

EFFECT: ensuring stable capturing of the read signal in conditions when the frequency of the shortest bit is higher than the cut-off frequency.

7 cl, 24 dwg