Minebea Company, Limited

Akio Takayama

Hideki Kato

Mitsuteru Inoue

Takeshi Matsushita

Motoji Egawa

Akiyo Yuguchi

Tamio Umehara

Atsushi Kitamura

Shigeyuki Adachi

Akinobu Sano

Kazutoshi Takayanagi

Toshitaka Fujii

Tetsuji Fujita

Akira Goto

Edward L Packard

Shoji Kaneko

A Faraday rotator of multilayer film type is provided which can achieve excellent optical characteristics with a reduced number of layers. In the Faraday rotator, a metal reflection film, a periodic dielectric multilayer film made of silicon dioxide SiOand tantalum pentoxide TaO, a magneto-optical thin film, and another periodic dielectric multilayer film made of tantalum pentoxide TaOand silicon dioxide SiOis formed sequentially. Light incident on a polarizer goes therethrough, is reflected at the metal reflection film while traveling trough the periodic dielectric multilayer films, and goes through an analyzer to exit out.

Faraday rotator with metal reflection film

A Faraday rotator of multilayer film type is provided in which satisfactory optical characteristics are obtained with a small number of layers. In the Faraday rotator, a first periodic dielectric multilayer film made of silicon dioxide SiO and tantalum pentaoxide Ta O is formed on a substrate, then a magneto-optical thin film, and a second periodic dielectric multilayer film made of tantalum pentaoxide Ta O and silicon dioxide SiO are formed sequentially. The first and second periodic dielectric multilayer films sandwich the magneto-optical thin film such that their respective higher refractive dielectric thin films are in contact with the magneto-optical thin film. The number of layers of the first periodic dielectric multilayer film is larger than that of the second periodic dielectric multilayer film.

Faraday rotator

This invention provides a magnetic optical member that can obtain a large magneto-optical effect using a rare-earth iron-garnet-based material and a method of producing the same.

Magnetic optical member with a polymer substrate

A reflection type Faraday rotator includes first to sixth reflection type sub-rotators. Light is made incident on the first to sixth sub-rotators while repeating reflecting thereat. A Faraday rotation occurs at a sub-rotator having a center wavelength equal to the wavelength of the light The sub-rotators are of reflection-type, have a larger bandwidth of outgoing light compared to a transmission type, and have center wavelengths (wavelength characteristics) different from one another. Thus, the effective wavelength range (the wavelength bandwidth) is increased. Expensive optical devices conventionally required for increasing the wavelength bandwidth are not needed. Accordingly, the cost can be reduced.

Reflection type faraday rotator with multiple reflection structure

A magnetic impedance element including a substrate made of a non-magnetic material, a thin-film magnetic core formed on said substrate, and first and second electrodes disposed on both ends of said thin-film magnetic core in a longitudinal direction thereof, characterized in that said thin-film magnetic core is formed by laminating a plurality of magnetic films through non-magnetic thin-films.

Magnetics impedance element having a thin film magnetics core

A raw material mixed solution containing nitrate or alkoxide of metal that constitutes a ferrite is sprayed from an atomizer by means of a carrier gas such as compressed air onto a substrate mounted on a hot plate and heated to a predetermined temperature. The method enables a thin film having a desired thickness to be formed by a simple apparatus in a short time without sacrificing good soft magnetism of a ferrite, thereby greatly contributing to downsizing and weight reduction of electronic devices.

Method of producing ferrite thin film

A Faraday rotator is provided which obtains excellent optical characteristics with a small number of layers. In the Faraday rotator, a metal reflective film is formed on a substrate, then a first periodic dielectric multilayer film made of silicon dioxide SiO and tantalum pentaoxide Ta O , a magneto-optical thin film, and a second periodic dielectric multilayer film made of tantalum pentaoxide Ta O and silicon dioxide SiO are formed sequentially. The number of layers of the first periodic dielectric multilayer film is larger than that of the second periodic dielectric multilayer film. Incident light from a polarizer passes through the periodic dielectric multilayer films, is reflected at the metal reflective film, returns through the periodic dielectric multilayer films, and passes through an analyzer to exit out.

The present invention provides a magneto-optical member capable of ensuring an excellent light transmittance and an optical isolator using the same. A first one-dimensional magnetic photonic crystal having a magneto-optical thin film, and a second one-dimensional magnetic photonic crystal having another magneto-optical thin film are laminated so as to sandwich a dielectric thin film with a small refractive index having an optical length of &lgr;/4&plus;m&lgr;/2 where &lgr; is a wavelength of light and m is 0 or a positive integer. Since a plurality of magneto-optical thin films are present as magnetic thin films and hence the total thickness of the magnetic thin films is increased, the Faraday rotation angle is increased. Also, a large light transmittance can be obtained because of the presence of the dielectric thin film with a small refractive index having (&lgr;/4&plus;m&lgr;/2) thickness where the first and second one-dimensional magnetic photonic crystals are laminated.

Magneto-optical member and optical isolator using the same

Magnetic impedance element having at least two thin film-magnetic cores

The present invention provides a compact optical isolator. A polarizer A and/or an analyzer B of an optical isolator are/is formed of a cobalt magnetic substance minute particle cluster thin film . The cobalt magnetic substance minute particle cluster thin film can be formed in the form of tape, film or sheet, whereby the thickness of the polarizer A and/or the analyzer B can be made small and in addition thereto, the polarizer and/or the analyzer can be formed integrally with a magneto-optical member which is formed in the form of thin film. More compact dimension and lighter weight can be realized as compared with the prior art in which Rochon prism made of calcite, rutile single crystal having wedge form or polarizing beam splitter is employed as the polarizer and the analyzer.

Optical isolator with a compact dimension

A floating magnetic head comprising a substantially rectangular slider made of a non-magnetic substance and having leading and trailing ends. The slider is provided with a groove which gradually increases in depth along one side of the slider extending toward the trailing end and has an opening at the trailing end. The slider has rails mounted on a surface of the slider that is opposite to a magnetic recording medium to produce a floating force. A magnetic head core is bonded to one side of the slider. The core has a read/write gap, first and second legs, an inclined face opposite to the bonding surface, and a track width on the surface opposite to the magnetic recording medium. The second leg is located at the trailing end of the slider without protruding from the trailing end.

Floating magnetic head having a magnetic head core fixed to a slider side surface

A magnetic sensor includes: an oscillating circuit for allowing an a.c. magnetic field into a magnetic impedance element made of a ferromagnetic substance, having first and second electrodes on both ends thereof in a longitudinal direction thereof and having a structure in which a bias coil and a negative feedback coil are wound around the ferromagnetic substance through an insulator; a detecting circuit for detecting an a.c. voltage of the magnetic impedance element due to a change in the impedance of the magnetic impedance element which is caused by an applied external magnetic field; a peak holding circuit for holding the peak value of the output voltage of the detecting circuit; and an amplifying circuit for differentially amplifying the output of the peak holding circuit.

Magnetic sensor

A floating magnetic head comprising a slider and a head core integral with the slider. The slider is made of a nonmagnetic material such as barium titanate or calcium titanate. The slider has rails on its surface opposite to a magnetic recording medium to produce a floating force. The head core has a read/write gap. The head core is equipped with a winding. The core is disposed on the outside of the slider and has a tapering thickness.

Floating magnetic head having a magnetic head core with a balanced

A floating magnetic head used in a hard disk drive has a substantially rectangular slider made of a non-magnetic material. The slider has rails mounted on a surface of the slider that is opposite to a magnetic recording medium to produce a floating force. A cut-out is formed in the slider, for example, at one corner of the slider for providing access for winding a coil and a bridge spans the cut-out portion. A head core having a read/write gap is bonded to an outer periphery of the slider adjacent the cut-out portion. In particular, a winding portion of the head core is bonded to the bridge spanning the cut-out portion for receiving a portion of a winding coil. Accordingly, if a large force acts on the head core during winding of the coil or mounting of the floating magnetic head to a suspension, the head core can withstand the force without incurring damage or adversely affecting its ability to function.

Floating magnetic head with a head core-reinforcing portion

A magnetic head which can be miniaturized while maintaining the performance thereof includes a thin film conductor coil assembly having a magnetic core connected magnetically to magnetic substances and stepping across a non-magnetic substance located between the magnetic substances of a substrate and a thin film conductor coil formed with the magnetic core as a thin film magnetic core. This thin film conductor coil assembly is attached to a slider provided with a magnetic head core. The magnetic head core includes an I-core in which magnetic substances are formed on both sides of a non-magnetic substance, and a U-shaped core composed of a magnetic substance, formed together in one integral body with a magnetic gap provided therein. This magnetic head core is fitted into a slit in the slider, and the thin film conductor coil assembly is attached thereon. With this construction, it is possible to form the thin film conductor coil into a thin film and to enlarge the magnetic path area, thereby to miniaturize the magnetic head while maintaining the performance thereof.

Growing community of inventors

Iwata-gun, Japan

Akio Takayama