Other

Hitachi Media Electronics Co., Ltd.

Nidec Copal Corporation

Naomitsu Kuroda

Michio Miura

Shinro Inui

Katsuhiko Izumi

Seiji Ono

Ryuichiro Mizuno

Naohiko Otoshi

Yasushi Kinoshita

Eiji Okubo

Katsuhiko Kimura

Seiichi Katou

Hidenao Saito

Yasushi Horie

An aspect of the invention provides an optical pickup in which an optical axis is not displaced even if ambient temperature is changed. The optical pickup of the invention has an optical unit and an optical pickup case. The optical unit has a lens member having an optical axis, and the optical axis of the lens member is offset to one side from the center of the optical unit. The optical pickup case holds the optical unit from both sides. A thermal expansion amount of the optical unit is absorbed by compression amounts of a first adhesive and a second adhesive such that the optical axis of the lens member is not displaced when the optical unit is thermal expanded.

Optical pickup having thermal expansion compensation

In an optical element feeding device and an optical pickup unit using the same, in order to make the device compact and light and achieve a stable operation, the device has a main shaft and a sub shaft supporting a movable frame in which an optical element is arranged in such a manner as to be movable in a direction of an optical axis, a stepping motor, a lead screw rotating on the basis of a rotation of the stepping motor, a resin nut engaging with the lead screw and being movable in the direction of the optical axis on the basis of the rotation of the lead screw, and a spring pressing the movable frame in the direction of the optical axis so as to bring the movable frame into contact with the nut, and a cushioning material is provided between the nut and the movable frame so as to connect the nut and the movable frame.

Optical element feeding device and optical pickup unit using the same

An optical element feeding device driving method and an optical disk apparatus capable of detecting biting in a stepping motor and conducting restoration. The optical disk apparatus includes an optical element feeding device including a movable frame for supporting a spherical aberration correcting lens to move the lens in optical axis direction, a spring for applying force to the frame in the direction, a sensor for detecting a lens reference position, a stepping motor, and a lead screw and a nut for converting motor rotation into the direction, a motor driving circuit, a decision circuit for judging abnormality when an output of the sensor does not change even if the driving circuit outputs a driving signal to the motor after reference position detection, and a changeover circuit for lowering a driving frequency than in ordinary operation, based on an abnormality signal.

Optical element feeding device driving method and optical disk apparatus

It is an object to perform a thin and compact design of the objective lens driving device. In order to achieve the above object, optical beam is passed through a space surrounded by a tracking coil and a focusing coil which are adjacent to each other and fixed in a holder. Further, it is another object to position the objective lens with high precision in an objective lens driving device for switching a plurality of objective lenses in accordance with the type of an optical disc. In order to achieve this object, magnetic substances which are radially extended with the sliding shaft at the center are provided in the lens holder, and the magnetic substances are located within a plane perpendicular to the plane constituting the magnetic gap and at the outside of the magnetic gap. Still further, in an objective lens driving device it is another object to prevent the occurrence of positional displacement of the objective lens due to resistance force of current supply means such as FPC. To achieve this object, a first objective lens and a second objective lens are arranged so that the objective lens arrangement angle at which the first and second objective lenses are arranged with respect to the shaft center of the sliding shaft is displaced, by a predetermined amount, from the magnetic circuit arrangement angle at which the magnetic substances and the magnets are arranged with respect to the shaft center of the sliding shaft.

Objective lens driving device and optical disc apparatus using the same

Growing community of inventors

Yokohama, Japan

Naomitsu Kuroda