Optical memory having narrowed track pitch

摘要

A transparent substrate of an optical memory is produced by injection molding using a stamper. Grooves and lands are alternately arranged on the optical memory, for tracking of light converged on the optical memory. The groove width is set in the range of 0.3 mu m to 0.4 mu m and the groove depth is set in the rage of 80 nm to 100 nm. A decrease in the width of a land at each edge is restrained to 0.2 mu m in maximum. With such dimensions, even when the track pitch is set to about 1.4 mu m, it is possible to obtain a track crossing signal with intensity sufficient for performing an access operation to a target track. Moreover, since the dimensions bring about an improved reflectance at a land, the optical memory achieves an improved C/N and recording density.