Sony Corporation

Takehiro Nagaki

Hiroyuki Uchida

Shunichi Hashimoto

Yutaka Soda

Masatoshi Hayakawa

Tetsuo Sekiya

Koichi Aso

Hiroshi Yamanoi

Junkichi Sugita

Shigeyoshi Imakoshi

Hideki Matsuda

Yoshitaka Ochiai

Nobuyuki Oka

Hiroshi Eto

Masayoshi Fujita

A geomagnetic direction sensor has a substrate, at least two magneto-resistive effect devices and a coil for generating the bias magnetic field. The substrate retains shape symmetry when rotated through 90.degree. and includes plural magnetic cores for converging the geomagnetism. The magnetic cores are arrayed circumferentially of the substrate and interconnected with one another by a non-magnetic material. At least two magneto-resistive effect devices are provided in register with the magnetic gaps so as to be substantially at right angles to one another and to the direction of the magnetic field of the geomagnetism in the magnetic gap region. The substrate also includes a coil for generating a bias magnetic field for impressing a bias magnetic field to each of the magneto-resistive effect devices.

Geomagnetic direction sensor

A magnetic head comprising a magnetic path and a vertically magnetizable film. The magnetic path contains a first gap facing a magnetic recording medium and a second gap. The vertically magnetizable film is formed across the second gap on the principal plane or outer circumference of the magnetic path. A linearly polarized light beam is irradiated onto the vertically magnetizable film and the resulting reversal of magnetization in the vertically magnetizable film is detected through the use of a polar Kerr effect. This scheme allows data to be reproduced with sufficient sensitivity from tracks of very small widths.

High density dual gap magnetic head using polar Kerr effect

An apparatus for generating a magnetic field varying in response to an information signal, which comprises a base plate made of electrical insulating material, a magnetic core mounted on one of opposite surfaces of the base plate, the magnetic core having a central leg portion extending through a hole formed in the base plate so as to cause its end face to appear on the other of the opposite surfaces of the base plate, a coil member wound on the central leg portion of the magnetic core to be supplied with a current varying in response to the information signal, and a capacitance detecting electrode formed with a thin conductive layer mounted on the other of the opposite surfaces of the base plate to be opposite to a recording medium having a conductive layer, the capacitance detecting electrode being provided with a cutout for restraining eddy current loss caused in the capacitance detecting electrode.

Apparatus for generating magnetic field varying in response to an

A device for producing a high frequency modulating magnetic field is disclosed. The device is especially useful to achieve real-time overwriting in magneto-optical recording. The device produces magnetic field modulated according to a signal to be recorded on a magneto-optical recording medium in which the signal is recorded in the form of magnetization direction on the magneto-optical recording medium under irradiation of a laser beam to raise the temperature of the medium. The device comprises a main magnetic pole formed of a low-loss soft magnetic material and having one end facing to the magnetic-optical recording medium and a sheathed conductor wound around the main magnetic pole and consisting of a parallel connection of a plurality of insulated elementary wires.

Device for producing a high frequency modulation magnetic field used in

A magnetic transducer head utilizing a thin film magneto-resistance effect element is disclosed in which the amount of a DC bias magnetic field is so selected that only the end portion of the thin film magneto-resistance effect element serving as a contact surface with a magnetic medium is effectively given with sensitivity and the element is saturated in the vicinity of its central portion in its width direction.

Magnetic transducer head utilizing magneto resistance effect with a bias

A magnetic transducer head having first and second magneto-resistance effect elements, each of which is made of a thin film having the magneto-resistance effect and which are arranged on approximately one line, a current source for flowing currents through the first and second magneto-resistance effect elements, and a bias source for applying bias magnetic fields to the first and second magneto-resistance effect elements. In this case, the bias magnetic field is selected from bias magnetic fields which have the direction of about .+-.(.pi./4).+-.(n/2).pi., where n is an integer, with respect to the currents flowing through the first and second magneto-resistance effect elements, and the current source and the bias source are so connected that when a uniform signal magnetic field is applied to the first and second magneto-resistance effect elements, the resistances thereof are varied in the opposite directions with respect to each other and the outputs from the first and second magneto-resistance effect elements are derived differentially.

Growing community of inventors

Miyagi, Japan

Takehiro Nagaki