Patent ID: 6665251
Filing Date: 2003-12-16
Classification: G11B

Abstract:
A processing method of a master for optical disk for forming grooves which configure a groove track, prepit groups on the same spiral or circumference as said groove track and prepit groups on the same spiral or circumference as a land track neighboring said groove track, comprising:a process for irradiating a laser beam on the master on which photosensitive material is coated in order to form prepit groups on the same spiral or circumference as said groove track; and a process for irradiating a laser beam on said master in order to form prepit groups on the same spiral or circumference as said land track, wherein each said irradiating process is alternately conducted by sequentially switching radial positions of irradiating a laser beam for forming the prepit groups while changing a circumferential position of said laser beam for forming the prepit groups on said master.