Patent ID: 7239602

Claim:
An optical information recording medium comprising information tracks extending in a circumferential direction and spaced from each other in a radial direction by lands, wherein: a first information track and a second information track are radially adjacent but are radially spaced from each other by a single land; a first phase pit encoding preformat information for a first groove in the first information track is connected to the second information track and extends radially therefrom toward, but does not reach, the first information track; said first phase pit and said first groove have substantially equal depths; said first phase pit is radially connected with another groove adjoining on a side of the pit away from the first groove; a partition wall is formed in a radial direction between said first phase pit and said first groove; and a track pitch of said first information track and a width and a length of said first phase pit are selected according to a condition that the preformat information for the first information track is reproduced from the first phase pit with a differential signal, wherein said first phase pit encodes preformat information for said first groove, is connected to said another groove, does not encode preformat information for said another groove and is not connected to said first groove.