Panasonic Corporation

Hideyuki Fujishima

Yasuhiro Wada

Satoshi Iwasaki

Shinji Matsumoto

An optical disk device that has a tilt correction unit for performing tilt correction to incline the optical axis of laser light based on a tilt between the recording layer of an optical disk and the optical axis of said laser light. The tilt is detected when the optical disk is activated. The optical disk device has a memory for storing a difference in temperature in accordance with the amount of the detected tilt. The difference in temperature is utilized for updating the tilt. The optical disk device engages said tilt correction unit to update said tilt, when a difference in temperature between activation of said optical disk and writing/reading information onto/from said optical disk is detected and when the detected difference in temperature has exceeded the stored difference in temperature corresponding to the amount of the detected tilt.

Optical disk device

During recording with an optical disk apparatus, an objective lens is moved toward the inner circumference and outer circumference of an optical disk in the radial direction thereof and also moved upward and downward, and the quantity of reflected light is measured at that time. Quantities of reflected light are determined taking advantage of the characteristic of laser heat that it is most efficiently used to provide the smallest quantity of reflected light when the relationship between the optical disk surface and the objective lens is closest to perpendicularity and when they are at a distance at which the point in focus is most closely approached. An optimum tilt value and focus position are learned from the result of the determination to allow operations to be performed at the optimum tilt and the optimum position of the point in focus.

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Fukuoka, Japan

Hideyuki Fujishima