Patent ID: 7391679

Claim:
An information recording medium having at least a read only area and a recording and reproducing area comprising at least: a substrate; a recording layer formed on the substrate so as to record and reproduce information; and a light transmitting layer having transparency formed on the recording layer, the information recording medium further comprising a wobbling groove corresponding to the read only area and another wobbling groove corresponding to the recording and reproducing area formed on the substrate without overlapping each other, wherein the recording and light transmitting layers are continuously adhered over at least two areas of the read only area and the recording and reproducing area, and wherein reflectivity of the recording layer is more than 5%, and wherein a push-pull signal output T 3 reproduced from the read only area and another push-pull signal output T 4 reproduced from the recording and reproducing area before recording satisfies relations of T 3 ≧0.1 and T 4 ≧0.1, and wherein each of the wobbling groove corresponding to the read only area and the other wobbling groove corresponding to the recording and reproducing area contains a wobbling groove modulated by any one of the frequency-shift keying method, the phase-shift keying method and the amplitude-shift keying method, and wherein a track pitch of the wobbling groove corresponding to the read only area is P 3 , another track pitch of the other wobbling groove corresponding to the recording and reproducing area is P 4 , a wavelength of reproducing light beam is λ and a numerical aperture of an objective lens for reproduction is NA, and wherein P 3 , P 4 , λ and NA satisfy relations of P 3 ≦λ/NA, P 4 ≦λ/NA and P 3 >P 4 .