An optical memory medium.

摘要

An optical memory medium is described comprising prepits (11, 11 min ) on which a light spot (5) is impinged to obtain information and, if required, guide grooves: each of those (11 min ) among the prepits (11, 11 min ) which are longer than the diameter of the light spot (5) consists of a series of pit portions (11a) and unpitted portions (12); each of the prepits (23) is sandwiched between two discontinuous portions (21a) of guide grooves (21) adjacent to each other; the guide grooves (21) have one or more narrow portions (21b), and each of the prepits (23) is sandwiched between two of the narrow portions (21b) of guide grooves (21) adjacent to each other; or the guide grooves (21) have one or more long portions (21h), one or more short portions (21j), and narrow portions (21i) formed between the long (21h) and short (21j) portions, and each of the prepits (23) is sandwiched between two of the short portions (21j) of guide grooves (21) adjacent to each other.