Hitachi-lg Data Storage, Inc.

Hitachi, Ltd.

Mitsuru Harai

Nobuhiro Takeda

Tsuyoshi Toda

Toru Kawashima

Koichiro Nishimura

Atsushi Yamada

Norimoto Ichikawa

Tomoya Hoshi

Test writing is executed while skipping areas where deviations are present on an optical disk to thereby improve accuracy and reliability of an optimum recording condition to be derived. A deviation detecting unit detects the deviations of a guide groove on the optical disk on the basis of a fluctuation amount of a focus error signal or a tracking error signal, and registers information of the detected deviations onto a memory. A test writing processing unit refers to the memory, and records and reproduces a test signal while skipping the areas where the deviations are detected.

Optical disk apparatus and test writing method

In a method for adjusting a focus position for an optical disc, onto/from which in formation is recorded or reproduced, while adjusting the focus position of an optical reproducing means, upon a recording surface of an optical information recording medium having an area where information of the optical information recording medium is recorded in advance, comprising the following steps of: memorizing plural numbers of information relating to focus positions determined appropriately, which can be obtained from the area where the information of the optical information recording medium is recorded in advance; and adjusting the focus position for the optical disc loaded into an apparatus, from at lease one (1) signal relating to the focus position, which can be obtained from the optical disc, with utilizing a relationship between the plural numbers of information relating to the focus positions determined appropriately, memorized in advance, when reproduction of the information is impossible when the optical disc is loaded into the apparatus, thereby providing the focus position adjusting method and an optical disc apparatus applying the same therein, for enabling an appropriate focus adjustment even in case when DMA area cannot read out due to damages or defects therein.

Method for adjusting a focus position on an optical disc and an optical disc apparatus applying the same therein

Disclosed is an optical disc apparatus that sets a plurality of virtual zones, which correspond to a plurality of zones that are arranged in the radial direction of an optical disc, for a plurality of recording layers of the optical disc. When a servo signal distortion is detected in a virtual zone to change the rotation speed of the optical disc to a low speed in the virtual zone during an information recording or reproduction operation relative to a first recording layer, the optical disc apparatus stores the change information. When a recording or reproducing operation is to be performed in a virtual zone of a second recording layer, which is in the same disc radial position as the virtual zone of the first layer, the optical disc apparatus changes the rotation speed of the optical disc for the virtual zone to a low speed in accordance with the change information.

Optical disc apparatus and information recording and reproducing method

An optical disc apparatus, as a learning operation before a recording or reproducing operation, rotates an optical disc at a first speed to read PID information, discriminates between lands and grooves of the optical disc, detects switching positions between lands and grooves, sets a rotation angle position of tracking pull-in of an objective lens of a time length that allows the PID information to be stably read, with respect to the switching position, and stores the set position information of tracking pull-in as learning result information. During recording or reproducing, the optical disc apparatus rotates the optical disk at a second speed higher than the first speed, pulls in the objective lens for tracking based on the stored position information of tracking pull-in, reads PID information, and performs the recording or reproducing operation while discriminating between lands and grooves and detecting switching positions between lands and grooves.

Optical disc apparatus and access control method of the same

In an optical disc device employing a CLV method, executing pickup return processing when focus drop occurs during recording poses problems of increased waiting time for rotation and increased focus servo recovery processing time. When defocusing occurs and focus pull-in cannot be achieved by retry, a first rotation frequency at a radial position thereof is calculated. Next, a second rotation frequency at the innermost circumferential position at the current speed is calculated. Next, a third rotation frequency at a radial position where recording is restarted after focus servo recovery is calculated. Next, a fourth rotation frequency at pickup return position at a different speed is calculated. Next, based on the relationship among the first to fourth rotation frequencies described above, a rotation speed at pickup return is selected so that a rotation frequency difference becomes the smallest in all conditions: at pickup return from defocusing, servo recovery after pickup return, and access operation after the servo recovery.

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Tokyo, Japan

Mitsuru Harai