Patent ID: 7590031
Filing Date: 2009-09-15
Classification: G06T,G11B

Abstract:
1. An optical disk comprising: a disk substrate; and a recording layer, a protective layer, and a reflective layer on the disk substrate, the recording layer including a magnetic film with a magnetic anisotropy in a direction perpendicular to a surface of the magnetic film; wherein the optical disk stores write-once information formed by first recording areas and second recording areas in a pre-determined portion of said recording layer; when the write-once information is recorded, the protective layer or the reflective layer is not destroyed by a laser beam; a magnetic anisotropy in a direction perpendicular to a surface of the second recording areas is smaller than a magnetic anisotropy in a direction perpendicular to a surface of the first recording areas; and a difference between a luminous energy that is reflected from the first recording areas and a luminous energy that is reflected from the second recording areas is not more than 10%.