BigPatents India

According to one embodiment, there is provided An optical disk including a first information layer having first guide grooves consisting of a first protrusive flat portion having a first width formed close to the light incidence side and a first recessed flat portion having a second width having a first height difference from the first protrusive flat portion and formed close to the opposite side of the light incidence side, the first information layer being formed on the transparent substrate layer, a second information layer having second guide grooves consisting of a second protrusive flat portion having a third width formed close to the light incidence side and a second recessed flat portion having a fourth width having a second height difference from the second protrusive flat portion and formed close to the opposite side of the light incidence side, the second information layer being formed on the adhesive layer, wherein a cycle P (|jm) of the first and second guide grooves has a value ranging from 0.35 jam to 0.8 urn and has a relationship of Q]_ = 2Z]_/(P - X]_ -, 0.2 = 2Z2/(P - X2 - Y2), 0.9 < Q2/Qi < 1.5, and 1 < < 4, 0.25 < X2/Y2 < 1 is satisfied.