| 摘要 |
PURPOSE:To make an optical recording medium into large capacity and high density. CONSTITUTION:This medium is an optical recording medium provided with a guiding groove for tracking which is formed concentrically or helically in the circumferential direction, the guiding groove is formed intermittently for the circumferential direction of the optical recording medium, and has regions A1, A2 in which a repetition period for the radius direction of the optical recording medium is made to be a period at least twice or more of the period in which a guiding groove is formed continuously. A tracking error is detected from a reflected light or a transmitted light from the regions in which a repetition period is made to be a period at least twice or more of the period in which a guiding groove is formed continuously. Therefore, tracking can be performed even if a track interval is narrowed to a diffraction limit of a light beam or less. |
