| 摘要 |
PROBLEM TO BE SOLVED: To improve the recording density, to stabilize the tracking and to make correctly reproducible multi-valued data by forming pits having two different depths on a substrate and making the wavelength of the light beams being used and the refractive index of the substrate of an optical recording medium satisfy a prescribed relationship. SOLUTION: Pits having two different depths (D1 and D2) are formed on the substrate of an optical recording medium, and it is constituted to satisfy 0<D1<λ/4n and λ/4nD2<2n, where λ is the wavelength of the light beams being used and n is the refractive index of the substrate of the medium. it is desirable to constitute the depths D1 and D2 of the pits so that λ/8n<D1<λ4n and λ/4n<D2<3λ/8n are satisfied. As to the method for reproducing optically recorded information, recorded data are reproduced by combining the signals based on the reflected light quantity of the medium and tangential push-pull signals. |
