Nidec Sankyo Corporation

Sankyo Seiki Mfg. Co., Ltd

Tsuyoshi Yokouchi

Takeshi Koshimizu

Manabu Sakamoto

Current sensor

An objective lens drive device includes a drive mechanism for driving a lens holder at least in a focusing direction and a tracking direction. The drive mechanism includes a drive magnet provided with a magnetized opposing face in which different magnetic poles are disposed to be adjacent to each other via a magnetic pole boundary portion formed in a roughly U-shape. The drive mechanism also includes a tilt drive coil for driving the lens holder in a tilt direction and the tilt drive coil is opposedly disposed to the magnetized opposing face at a position where the tilt drive coil overlaps with at least a focusing drive coil or a tracking drive coil in a direction in which the focusing drive coil and the tracking drive coil face the magnetized opposing face.

Objective lens drive device and optical head device

An objective lens driving system in an optical pick-up comprises a lens holder which has a shaft hole and holds an objective lens, a fixed member which has a journal inserted into the shaft hole, a magnet and a driving coil which are arranged opposite each other so as to generate a magnetic force for driving the lens holder along the journal and a magnetic piece which is arranged opposite the magnet to hold the lens holder at a predetermined neutral position using the magnetic force generated between the magnet and the driving coil while the driving coil is not excited and is magnetized until it is saturated by emf from the magnetic field generated by the magnet. Each of the magnet and magnetic piece has an associated magnetic flux density; the magnetic flux density generated by the magnet is larger than the saturation flux density around the magnetic piece.

Growing community of inventors

Nagano, Japan

Tsuyoshi Yokouchi