Patent ID: 7050365
Filing Date: 2006-05-23
Classification: G11B

Abstract:
1. An optical disk apparatus for writing or reading information by irradiating a laser beam onto an optical disk while rotating the optical disk under a focus control of the laser beam relative to the rotated optical disk, the apparatus comprising: an irradiating section that irradiates the laser beam onto the optical disk; a determining section that determines a process pattern of the focus control by operating the irradiating section to irradiate the laser beam onto a predetermined area of the optical disk and by monitoring the laser beam reflected back from the predetermined area; and a focusing section that performs the focus control to regulate a spot diameter of the laser beam based on the determined process pattern during either of the writing or reading of information, wherein the determining section operates the irradiating section to irradiate the laser beam along a predetermined round area during at least one turn of the optical disk, and monitors the laser beam reflected back from the predetermined round area so as to determine one round process pattern of the focus control in function of an angular position of the rotated optical disk, and wherein the focusing section performs the focus control based on the determined one round process pattern in response to the angular position of the rotated optical disk.