| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to sufficiently obtain the modulation degree of address pit parts in spite of an optical recording medium having a sector structure. SOLUTION: Concentric or spiral pregrooves PG having phase depth of λ/(8n) are formed on the surface side where the recording layer of a transparent layer 2 is deposited and formed when the wavelength of a beam for recording and reproducing is defined as λ and the refractive index of the transparent layer 2 allowing the transmission of the beam for recording and reproducing as n, respectively. Address pits AP having the phase depth of λ/(4n) are formed in the regions held by these pregrooves PG and at the ends of respective sectors. |
