Patent ID: 7251200
Filing Date: 2007-07-31
Classification: G06T,G11B

Abstract:
1. An apparatus for reproducing optical disks, wherein an optical head irradiates linearly polarized light onto an optical disk, and a change of a polarization orientation of light that is transmitted or reflected from the optical disk is detected in accordance with a recording signal on the optical disk; and the apparatus comprises: means for moving, when necessary, the optical head into a pre-determined portion of the optical disk where write-once information is stored, and means for reproducing the write-once information after detecting a change of a polarization orientation of light that is transmitted or reflected train the pre-determined portion, the write-once information being recorded by lowering the magnetic anisotropy in a direction perpendicular to a surface of the recording film to create a low level magnetic anisotropy in a direction perpendicular to the surface of the recording film.