Panasonic Corporation

Jtekt Corporation

Kyodo Yushi Co., Ltd.

Hirofumi Inoue

Hiroshi Inukai

Shinji Yamane

Junichi Imai

Yutaka Imai

Norio Hatanaka

Ryuji Nakata

Hideo Shibata

Yuta Sato

Ryosuke Saito

Koji Yoshizaki

Ryoichi Ishikawa

Yoichiro Sankai

A grease composition includes a base oil, a thickener, and an additive. The base oil contains a synthetic oil. The thickener contains a compound having a urea group. The additive contains a phosphoric compound, a calcium-based compound, and a hydrocarbon-based wax. A hub unit includes the grease composition enclosed therein.

Grease composition and hub unit

To discriminate a disk in a short time, a calculating partmeasures an amplitude of one of a focus error signal and a tracking error signal, which are output from a differential signal generating part, several times, and outputs the measured amplitudes to a controller. The controllercompares the input amplitudes with threshold values stored in a memory, respectively, and determines whether or not an amplification gain of one of the focus error signal and the tracking error signal is changed. If it is determined that the amplification gain of one of the focus error signal and the tracking error signal is changed, the controllerchanges the amplification gain of one of the focus error signal and the tracking error signal to an amplification gain represented by one of the threshold values and discriminates the kind of an optical disk based on the changed amplification gain.

Disk discriminating method and disk discriminating apparatus

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Osaka, Japan

Hirofumi Inoue