Patent ID: 7307937

Claim:
An information recording medium comprising a track in which information composed of a plurality of codes different in length is recorded, wherein the next shortest code after the shortest code included in the plurality of codes if formed on the track so that the result of evaluating a reproduced signal based on the reproduced signal of the next shortest code satisfies a specific evaluation level, wherein if the maximum value of the reproduced signal of the next shortest code after the shortest code reproduced from the information recording medium is IbH and the minimum value of the reproduced signal is IbL, and the amplitude of the reproduced signal of the longest code or a code three times or more as long as the shortest code reproduced from the information recording medium is Ic, the maximum value of the reproduce signal is IcH, and the minimum value of the reproduced signal is IcL, the value of {(IcH+IcL)/2−(IbH+IbL)/2}/Ic×100 is equal to or more than −10 and equal to or less than 10.