Funai Electric Company Ltd.

Katsuichi Inoue

Nobuyuki Kimura

Teruaki Sogawa

Takayuki Murakami

Takashi Kasahara

A defocus adjustment method includes a step of storing in a memory a range of defocus values for smooth operation of an optical disc apparatus, a step of measuring the defocus value of the optical disc loaded in the optical disc apparatus, a step of comparing the defocus value and the range of defocus values, a step of determining the optimal defocus value, and a step of using the optimal defocus value as a focusing bias value. This helps easily and quickly perform defocus adjustment that suits the loaded optical disc. Using as a focus bias value the defocus value determined through the defocus adjustment helps enhance the quality with which data is read from and data is written to the optical disc.

Optical disc apparatus and defocus control method

In a processing section, allowable gain-value range defining unitmeasures a gain value k corresponding to a level ratio between an MPP signal and an SPP signal generated by a tracking error signal generating circuitto define an allowable range of the gain value, and eccentricity measuring unitmeasures an eccentricity of an optical disk. If the eccentricity is determined to be greater than or equal to a predetermined value by eccentricity determining unit, gain-value defining unitselects a minimum value of the gain value k to define the minimum value as a gain value k of an amplifier. On the other hand, if the eccentricity is determined to be less than the predetermined value, the gain-value defining unitselects a central value of the gain value k to define the central value as the gain value k of the amplifier

Optical disk recording/reproducing apparatus

In an optical disc apparatus, a loading operation and an unloading operation are performed a plurality of times while changing the movement speed of a tray. A movement speed of the tray at which a shock that is produced during a movement of the tray is smaller than an upper limit, and a time period required for the loading operation and the unloading operation is shortest is determined as the movement speed of the tray in the loading operation and the unloading operation. An optical disc placed on the tray can be prevented from being damaged by a shock produced during a movement of the tray, and the time period required for the loading operation and the unloading operation can be prevented from being prolonged.

Optical disc apparatus which determines tray movement speeds

When a MD is inserted (step S ), AGC is executed for reading the TOC area of the MD , and thereafter the information stored in the TOC area of the MD are read to detect the kind and recording capacity, etc. of the MD (step S S ). Next, the data relative to the executing position of AGC corresponding to the kind of the detected MD is read out from the memory (step S ). Now, where the MD is of a pre-mastered type, according to the recording capacity, either the first executing position P or the second executing position P is read as occasion demands. On the other hand, where the MD is of the recordable type, two AGC executing positions of the first executing position R in a pit area and the second executing position R in a groove area are read out. At each of the executing positions thus read out, the AGC is executed (step S ).

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Osaka, Japan

Katsuichi Inoue