| 摘要 |
PROBLEM TO BE SOLVED: To obtain a disk of deep grooves capable of surely avoiding cross erasure, by forming concentric or spiral grooves on a substrate, tapering at least one flank of the grooves, setting the angle of inclination of the one flank thereof smaller than the angle of inclination of the other flank and forming a recording film so as to cover these grooves. SOLUTION: The flanks 22b on the outer peripheral sides of the grooves 22 and the flanks 23a on the inner peripheral sides of the grooves 23 of the substrate 11 are tapered in compliance with the directivity of the particles 3, 3,... flying from an erosion region 41A at the time of deposition of the recording film. Then, the particles 3, 3 made incident from a diagonal direction on the substrate 11 may be made to arrive at the groove parts 22d, 23d of the deep grooves 22, 23 without being shut off by the land parts 22c, 23c merely by making the diameter of an erosion region 41A coincident with the diameter of the specific circumference 11a of the substrate 11. Consequently, the deposition of the recording film by equaling the film thicknesses of the respective parts is made possible even if the depth of the grooves 21 to 23 of the optical disk is increased. |
