Hitachi-lg Data Storage, Inc.

Masamichi Ito

Hiroshi Minoda

Provided is an optical disk drive including: an actuator for driving an objective lens for applying a beam from a laser to an optical disk to cause a focal point of the beam to move in a focus direction; and a servo controller for receiving an input of a focus error signal and driving the actuator to control a focusing position of the beam, which includes: a compensation unit for generating a drive signal for the actuator based on the focus error signal; a noise detection unit for detecting a noise component by changing a limiter characteristic according to a frequency of the drive signal; and a correction unit for correcting the drive signal by subtracting the noise component from the drive signal. Accordingly, an influence of a tracking error signal leaking into the focus error signal in a focus servo system can be reliably suppressed.

Optical disk drive

In an optical disk apparatus and a disk rotation speed control method thereof, enabling to rotate a disk at high speed, with stability and certainty, irrespective of mass eccentricity thereof, detection is made on the greatest value and the smallest value on the signal after conducting a process of a band pass filteron a lens error signal in a step response of a pickup, with using a wobble signal in the place of a tracking error signal and chaining an offset, when controlling the rotation speed of the apparatus by loading an optical disk therein, and thereafter, determination is made on whether the disk rotation speed be shifted to the high speed or not, upon basis of a value obtained through comparison of the maximum value (Max_spnup) and the minimum value (Min_spnup) obtained with the greatest value (Max_step) and said smallest value (Min_step) memorized, when shifting the disk rotation to the high speed.(Max&#x2212;Min)/(Max_step&#x2212;Min_step)

Optical disk apparatus and disk rotation speed control method thereof

An optical disk apparatus configured to be compatible with a plurality of disk types includes an objective lens to focus a laser beam onto an optical disk provided in the apparatus. A drive mechanism is coupled to the objective lens to enable tilting of the objective lens to a plurality of tilt angles. A first signal detection circuit is configured to receive and process a first information signal associated with information read from the optical disk and to output a data signal derived from the first information signal. A second signal detection circuit is configured to receive and process a second information signal associated with information read from the optical disk and to generate a first track error signal. A third signal detection circuit is configured to receive and process a third information signal associated with information read from the optical disk and to generate a second track error signal. A digital signal processor is coupled to the first, second, and third signal detection circuits and is configured to determine a disk type of the optical disk and perform a first tilting technique on the lens if the optical disk is determined to be a first disk type, a second tilting technique on the lens if the optical disk determined to be a second disk type, and a third tilting technique if the optical disk is determined to be a third disk type.

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Fujisawa, Japan

Masamichi Ito