| 摘要 |
PURPOSE:To form a ventilation type optical information recording disk of long service life by forming a group projecting to a disk substrate. CONSTITUTION:A group 2 is formed in form of projecting stripe and formed spirally around the center of rotation of the disk substrate 1. The group 2 is formed making its height lambda/8<=H<l/4 when wavelength of laser light for reproduction is l, width (l) 0.4mum-0.5mum, and pitch (p) between groups 1.2mum-1.7mum. A prepit 3 is formed on the group 2 and the depth D is formed lambda/8<=D<lambda/4 when wavelength of laser light for reproduction is lambda. |
