Patent ID: 6934244

Claim:
An optical recording medium which data is recorded onto and/or played back from with a light beam directed thereto, comprising: a land which spirally runs on the recording medium; a first groove formed along one surface of the land and having a depth of d 1 ; and a second groove formed along the other surface of the land and having a depth of d 2 , which is different from the depth of d 1 of the first groove, wherein two optical detectors symmetrically arranged with respect to the center of a track formed of the land or the grooves detect light beams that are reflected from the optical recording medium when the optical recording medium is irradiated with the light beam, and the depths d 1 and d 2 satisfy the condition that the level ratio of an AC component of a sum signal represented by A+B to a DC component of the sum signal is 0.15 or smaller where A is the output level of the one optical detector and B is the output level of the other optical detector.