| 摘要 |
PURPOSE:To stabilize a tracking servo signal by using the assembly of fine grooves to form the track grooves of rugged preformats in an optical card substrate formed with the rugged preformats. CONSTITUTION:The track grooves 2 consisting of the assembly of the fine grooves 4 are formed on the transparent substrate 1 and an optical recording layer 3 is formed thereon. Differences in reflectivity are then generated by the edge effect of the fine tracks and the tracks are formed by the small ruggedness, by which the high contrast is obtd. even if the track depth is small. The molding distortions of the track grooves are, therefore, decreased and the formation of the optical recording layer in the track grooves to a uniform thickness is enabled. The tracking signal is thus stabilized. |
