Sony Corporation

Kietsu Iwabuchi

Tamotsu Yamagami

Tetsu Watanabe

Koji Sasaki

Yoshio Aoki

Hideo Suyama

Kazuo Kurihara

Yoshihisa Kawamura

Toshio Aizawa

Zenkichi Nakamura

A geomagnetic direction sensor has a plurality of magnetic cores for converging terrestrial magnetism arranged circumferentially with pre-set gaps, and magneto-resistive effect devices in the gaps so as to lie substantially at right angles to the direction of the magnetic field in the gaps. The geomagnetic direction sensor has at least a pair of magneto-resistive effect devices lying substantially at right angles to each other. The magnetic core is formed of a magnetic material having soft magnetic properties. The current is supplied to the excitation coils placed around the magnetic core for applying a bias magnetic field to the magneto-resistive effect devices. Another set of magneto-resistive effect devices are connected in series with the magneto-resistive effect devices arranged within the gap so as to be substantially parallel to the direction of the magnetic field.

Geomagnetic direction sensor

A magneto-optical pickup apparatus includes an objective lens for focusing a laser beam emitted from a laser device onto a magneto-optical recording medium, driving coils, on which the objective lens is mounted, for driving the objective lens in focusing and tracking directions, and a plate arranged at an end portion of the driving coils between the objective lens and the magneto-optical recording medium. The plate is formed with a coil pattern for generating a magnetic field to be applied to the magneto-optical recording medium, and can allow a laser beam transmitted through the objective lens to pass therethrough.

Magneto-optical pickup apparatus and magneto-optical

Growing community of inventors

Miyagi, Japan

Kietsu Iwabuchi