To permit precise tracking servo and to obtain a high reflectivity with an optical information medium.
The optical information medium has a translucent substrate 1 which transmits recording light, grooves 3 for tracking which consists of spiral grooves formed on the surface of this translucent substrate 1, lands 4 between these grooves 3, a recording layer 12 which is formed on the surface of the translucent substrate 1 formed with these grooves 3 and lands 3 and a reflection layer 13 which is formed on this recording layer 12 and reflects recording and reproducing light. Optically readable signals are recorded by the recording light made incident from the translucent substrate 1. The length (d) in the front surface part of the lands is specified to 3≤d≤0.45 μm.
FUJII TORU
TOMIZAWA SUKEHISA
NEGISHI MAKOTO
HAMADA EMIKO
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