Olympus Optical Company, Ltd.

Hiroshi Ezawa

Tetsuo Ikegame

Junichi Nakano

Nobuhide Matsubayashi

An optical pick-up apparatus for writing and/or reading information on and/or from an optical record medium including a light source, an objective lens projecting a light beam emitted by the light source onto the optical record medium, a holding member holding the objective lens movably in a focusing direction to perform a focusing control, a carriage to which the holding member is secured, a supporting mechanism for supporting the carriage movably in a tracking direction to effect a tracking control as well as an access control, and a driving member moving a movable member including the objective lens, holding member and carriage in the tracking direction. The supporting mechanism includes guide rails extending in the tracking direction and slide bearings formed in the carriage and coupled with the slide bearings. A coefficient of static friction of the movable member is set to a value not larger than 0.25.

Optical pick-up apparatus having low coefficient of friction between

An optical system driving apparatus includes a holding member holding an optical element and having first and second surfaces facing in opposite directions, and a carriage having first and second surfaces which contact the surfaces of the holding member and slidably clamp the surfaces of the holding member. At least one of a slidable contact surface portion of the first surface of the holding member which corresponds to the first surface of the carriage and a slidable contact surface portion of the first surface of the carriage which corresponds to the first surface of the holding member is formed into an at least partly spherical shape having a center coinciding with an optical center of the optical element, and the other portion guides the holding member to move in a circumferential direction of the spherical slidable contact surface portion. Further, at least one of a slidable contact surface portion of the second surface of the holding member which corresponds to the second surface of the carriage and a slidable contact surface portion of the second surface of the carriage which corresponds to the second surface of the holding member is formed into an at least partly spherical shape having a center coinciding with the optical center, and the other portion guides the holding member to move in a circumferential direction of the spherical slidable contact surface portion.

Optical system driving mechanism for an optical system driving apparatus

An optical system driving apparatus including a holder 2 supporting an objective lens 1, resilient supporting members 29a, 29b for supporting the holder movably in a focusing direction Z perpendicular to a record medium, and focusing coils 4a, 4b secured to the holder 2 by means of viscoelastic members 3a and 3b. The focusing coils 4a, 4b and a viscoelastic members 3a, 3b serve as a dynamic damper so that undesired resonance can be effectively suppressed without narrowing a control frequency range.

Optical system driving apparatus

Write data, which has been modulated in a 4/11 mode and converted in an NRZI mode, is written on a sample servo type optical disk by means of a magnetic head and a laser diode in a pickup. A signal reproducer in an optical disk unit comprises a differentiating circuit for differentiating a reproduced signal originating from data recorded on the optical disk after detected by the pickup, an A/D converter for sampling a differential signal synchronously with a channel clock, and a difference detector for reproducing data by performing difference detection on results of A/D conversion. The difference detector includes a register, a selector, and a determiner.

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Sagamihara, Japan

Hiroshi Ezawa