| 摘要 |
PROBLEM TO BE SOLVED: To make the calculated value of a tracking signal coincide with the actual measurement in the case where the wavelength of laser light radiated on an optical recording medium is short by considering a laminated structure and a groove shape. SOLUTION: In the optical recording medium with a pre-grooved transparent substrate 1, a light transmissive middle layer 2 laminated on the pre-grooved surface and a light reflecting layer 4, when the appropriate range of a groove width at the interface between the middle layer and the reflecting layer calculated from the optical system (the NA of the objective, etc.), of a recorder or a reader used, the wavelength of radiated light and a required tracking signal value is represented by W(0)min to W(0)max and the thickness of the middle layer 2 is represented by (d), the groove width of the substrate 1 is in the range from W(0)mn+0.08 d to W(0)max+0.4 d. |
