Matsushita Electric Industrial Co., Ltd.

Akio Kuroe

Akio Murata

Sayuri Muramatsu

Masaru Higashionji

Kenji Kondo

Hiroshi Sakakima

Mitsuo Satomi

Hirotsugu Fusayasu

Takaaki Maegawa

Eisuke Sawai

Ken Takahashi

Osamu Kusumoto

Masafumi Shimotashiro

Kazuo Yokoyama

Taizou Hamada

Yoshihiro Tosaki

Hiroshi Kanchiku

Yoshihiko Morioka

In order to obtain a magneto-impedance type magnetic sensor having a soft magnetic film facing to a conductive nonmagnetic film, and available a large impedance change with a carrier signal at a relatively low frequency, the magnetic sensor comprises a meander type conductive nonmagnetic thin film of zigzag shape formed with at least one pair of electrode terminals at both ends and a soft magnetic film which is strip-shaped so as to face thereto at a plurality of regions and has an easy axis of magnetization in a width direction of the strip shape, a high frequency carrier signal is applied to the above-mentioned electrode terminals and further a direct current bias magnetic field is applied. By performing AM detection of an AM modulation signal output from the above-mentioned electrode terminals, an impedance change of the conductive nonmagnetic film which is changed by external magnetic field is detected as a change of the high frequency carrier signal, thereby the external magnetic field can be detected.

Magnetic sensor having a closed magnetic path formed by soft magnetic films

In a high-frequency impedance type magnetic head having high impedance and capable of efficiently detecting a change in impedance, an electrically conductive metal film is sandwiched between two soft magnetic films, and the two soft magnetic films form a portion of a magnetic path. The thickness of one soft magnetic film is smaller than the thickness of the other soft magnetic film. The electrically conductive metal thin film has a pair of electrodes at respective ends thereof, to which are connected an oscillator for applying a high frequency carrier signal to the electrodes and a high frequency amplifier having a demodulator circuit. Further, an electrically conductive metal film winding is provided, and a DC current is applied to the electrically conductive metal film winding at the time of reproduction, while on the other hand, a signal current is applied to the electrically conductive metal film winding at the time of recording.

Magnetic head

Magnetic sensing apparatus having a central core with wire therethrough

A shielded magnetic head includes a magnetically shielded gap and first to fourth conductive magnetic films disposed in the gap. The first to fourth conductive magnetic films, each extending parallel to a tip face of a magnetic head to be opposed to a magnetic recording medium, are aligned at a distance from one another in a direction perpendicular to the tip face so as to be away from the tip face in ascending order and connected to one another so as to form a bridge circuit. The distance between the first conductive magnetic film and the tip face is set so that a signal magnetic field from the magnetic recording medium is applied to the first conductive magnetic film. By canceling impedance components that do not vary depending on a magnetic field, the shielded magnetic head detects only impedance components that vary depending on a signal magnetic field.

Shielded magnetic head and magnetic reproducing apparatus

A magnetic head unit of the present invention is provided with a magnetic head having a magnetic impedance element, and a head suspension for suspending the magnetic head is provided with a matching transmission line of one-fourth wavelength for transmitting a high-frequency signal output from the magnetic head.

Magnetic head apparatus including a quarter wavelength transmission line

A magnetic head includes a first, second and third magnetic core of a soft magnetic film formed by a thin film forming method. One end of the first and second magnetic core face a magnetic recording medium and are disposed with a predetermined distance therebetween. The third magnetic core is disposed between the first and second magnetic cores. A conductive coil is wound around the third magnetic core. A conductive wire passes through the third magnetic core and is insulated therefrom. A DC-biased high-frequency constant current flows through the conductive wire to reproduce information recorded on the magnetic recording medium. Also, a recording signal is applied to the conductive coil.

Magnetic head and reproducing apparatus with head having central core

The present invention relates to a magnetic head for recording and reproducing signals from a magnetic recording medium, wherein the magnetic head comprises a stylus having a pair of electrodes, a conductive multilayer film having a staircase-shaped section, and a magnetic body formed on the multilayer film. The magnetic head further comprises an excitation conductive thin film disposed so as to surround the stylus, a magnetic yoke forming a closed magnetic loop together with a magnetic recording medium and the stylus, and an anti-abrasive film formed on the magnetic yoke so as to oppose the recording medium. During recording, a signal current is supplied to the excitation conductive thin film to generate a recording magnetic field from the end of the stylus. During reproduction, a high-frequency voltage is applied across the electrodes, and a magnetic impedance change of the stylus, caused by a signal magnetism on the recording medium, is detected. The relative position of the magnetic head to the recording medium is controlled by deflecting a cantilever according to a capacitance between the magnetic head and the recording medium. Accordingly, the magnetic head of the present invention is capable of remarkably enhancing recording densities and data transfer rates.

Magnetic head for use with a recording medium

A magnetic recording/reproducing apparatus according to the present invention includes: a fixed cylinder; a rotary cylinder rotatably supported by the fixed cylinder, the rotary cylinder including a disk-shaped magnet in which first areas having a first pole and second areas having a second pole opposite to the first pole are alternately arranged; and a head chip attached to the rotary cylinder, wherein the fixed cylinder has a stator coil for generating a magnetic force between the stator coil and the disk-shaped magnet, thereby rotating the rotary cylinder, and the head chip is placed on the rotary cylinder so that a phase angle .theta. between a virtual plane including a center of a head gap of the head chip and a rotation axis of the rotary cylinder and one of two polar boundary planes sandwiching the area where the virtual plane traverses satisfies 0.4.alpha..ltoreq..theta..ltoreq.0.6.alpha., where a central angle of the area is .alpha..

Magnetic recording/reproducing apparatus having an offset head chip

In a magnetic recording and reproducing apparatus, a recording current setting circuit sets a recording current to be larger by 1 dB or more than a recording current which maximizes a reproduced signal level in correspondence to the shortest recording wavelength in digital signals to be recorded. Recording is performed with a magnetic head onto a metal powder tape including a magnetic layer of thickness having a 0.2 .mu.m or less. Thus, an overwrite characteristic can be obtained which are generally similar to that of a metal evaporation tape. Further, on reproduction, either an output from a equalizer circuit for a metal evaporation tape or an output from another equalizer circuit for a metal powder tape is selected by a switch circuit according to an output of a tape type detection circuit, and loop control gain of a tracking control circuit is changed according to the detected tape type. Thus, both metal powder tapes and metal evaporation tapes can be used.

Digital signal magnetic recording and reproducing apparatus for both

In the magnetic recording characteristics of recording apparatus, when there are three or more magnetic tips disposed on one head base, the extension lines in the depth direction of the head tips pass through the central line of the cylinder. The both outermost head tips on the head base disposed in one window of the cylinder possess head gaps as dummy head, but do not have the function of magnetic recording characteristics of recording, reproducing and erasing. In the disclosed multiple magnetic head, the materials of the head tips on one head base including the dummy head are the same.

Multiple-channel magnetic head having plural magnetic head tips mounted

Amorphous magnetic head

A magnetic recording medium which comprises a base film having a multitude of fine projections uniformly distributed over one surface thereof, and a magnetic layer formed on the base film. The magnetic layer is made of magnetic acicular particles extending from the individual projections in a vertical direction with respect to the base film, and a resin composition comprising a lubricant. The resin composition fills substantially all gaps formed among the vertically extending magnetic acicular particles. This medium may be formed on another magnetic recording medium for longitudinal recording.

Magnetic recording mediums for high density recording comprising an

A pair of half core pieces is bonded by a high lead glass bond having a low melting point, which is formed on a metal layer of small wetting angle, such as Cr, Cu, Ag, Ti, the metal layer being formed by spattering at least on a part adjacent to a plane of gap of each core piece.

A magnetic head cleaning tape cartridge is disclosed which comprises a length of cleaning tape assembly consisting of a transparent and relatively rigid leader tape, a cleaning tape which has a layer made of fibrous materials for intimate contact with the surface of a magnetic head and has a lower transmissivity than the leader tape, and a transparent trailer tape; a supply reel around which is wrapped the cleaning tape assembly; and a cartridge case containing the reel.

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Katano, Japan

Akio Kuroe