Hitachi Maxell, Limited

Maxell, Ltd.

Maxell Holdings, Ltd.

Masao Fujita

Sadamu Kuse

Toshio Hiroi

Kenji Tanaka

Shinji Kawakami

Masayuki Toyoda

Toshio Kawakita

Seigi Kawarai

Kenichiro Yoshida

Issei Watanabe

The present invention realizes an electric-wave absorber of a so-called electric-wave interference type, which can favorably absorb absorption electric waves of a desired frequency even when a protective layer for protecting an electric resistance film is formed on the surface of the electric resistance film, and a manufacturing method for the electric-wave absorber. In an electric-wave absorber of an electric-wave interference type, which is formed by sequentially stacking an electric resistance film, a dielectric layer, and an electric-wave shielding layer, absorption electric waves to be absorbed by the electric-wave absorber are waves in a high frequency band in or above a millimeter-wave band, a protective layeris included on the electric resistance film, and a thickness of the dielectric layer is smaller than a reference thickness dst obtained according to the frequency of the absorption electric waves and the permittivity of the dielectric layer.

Electric-wave absorber and manufacturing method for electric-wave absorber

To provide a transmission-type electromagnetic-wave absorber that can satisfactorily absorb electromagnetic waves of high frequencies in or above the millimeter wave band while reducing the reflection of electromagnetic waves on the surface of the absorber. The transmission-type electromagnetic-wave absorber includes an electromagnetic-wave absorbing layercontaining a magnetic iron oxidea that magnetically resonates at a frequency in or above the millimeter-wave band and a binderb containing an organic material. The real part of the complex relative permittivity of the electromagnetic-wave absorber is 5.5 or less at 1 GHz.

Electromagnetic wave absorber

Provided are a measurement system and a radio wave shielding member that include a radio wave absorber that has light transmittance and absorbs radio waves other than the radio waves to be measured, and thus is suitable for the measurement of radio wave properties. The measurement system includes a measuring target device, a measuring devicethat emits and/or receives radio waves to measure the measuring target device, and a radio wave absorberthat has light transmittance and absorbs radio waves in and above the millimeter wave band. The radio wave absorber includes a transparent support memberand a radio wave absorbing sheetthat is attached to one surface of the support member. The radio wave absorbing sheet includes a resistive film, a dielectric layer, and a radio wave shielding layerwhich are stacked on top of each other and all of which have light transmittance. The radio wave absorber blocks and/or absorbs unwanted radio waves around the measuring target device.

Measurement system and radio wave blocking unit

Provided are an electromagnetic-wave absorbing composition that can favorably absorb electromagnetic waves of high frequencies in or above a millimeter-wave band and that can be applied to a desired portion in the form of a paste, and an easily deformable electromagnetic-wave absorber having flexibility. The electromagnetic-wave absorbing composition includes a rubber binder, a filler made of a particulate carbon material, and a magnetic iron oxide that magnetically resonates in a frequency band in or above a millimeter-wave band as an electromagnetic-wave absorbing material. The electromagnetic-wave absorber includes a rubber binder, a fillermade of a particulate carbon material, and a magnetic iron oxide that magnetically resonates in a frequency band in or above a millimeter-wave band as an electromagnetic-wave absorbing material, and is a nonresonant-type electromagnetic-wave absorber that is not provided with a reflective layer for reflecting incident electromagnetic waves.

Electromagnetic wave absorbing composition, and electromagnetic wave absorption body

Provided is an electromagnetic-wave absorber composition and an electromagnetic-wave absorber that can favorably absorb a plurality of electromagnetic waves of different frequencies in a high frequency band in or above the millimeter-wave band. The electromagnetic-wave absorber composition includes a magnetic iron oxide that magnetically resonates at a high frequency in or above the millimeter-wave band and a resin binder. The electromagnetic-wave absorber composition has two or more extrema separated from each other on a differential curve obtained by differentiating a magnetic property hysteresis loop at an applied magnetic field intensity of from 16 kOe to &#x2212;16 kOe. The electromagnetic-wave absorber includes an electromagnetic-wave absorbing layer formed of the above-described electromagnetic-wave absorber composition.

Electromagnetic wave absorbing composition and electromagnetic wave absorbing body

An electromagnetic wave absorbing sheet is provided that can adequately absorb electromagnetic waves at high frequencies in and above the millimeter wave band, can have excellent flexibility, and can easily be placed in any desired portion. The electromagnetic wave absorbing sheet includes an electromagnetic wave absorbing layercontaining a magnetic iron oxidethat magnetically resonates at frequencies in and above the millimeter wave band and a resin binder. The electromagnetic wave absorbing sheet absorbs radiated electromagnetic waves by magnetic resonance of the magnetic iron oxide. The electromagnetic wave absorbing sheet has a flexibility evaluation value F (g/mm) of more than 0 and 6 or less, which is determined by measuring an applied weight (g) that is required to bend a ribbon-like electromagnetic wave absorbing sheet in the elastic deformation region so that a distance d between the inner surfaces of the ribbon-like sheet at a position L spaced 10 mm from the bent portion of the ribbon-like sheet is 10 mm, and dividing the applied weight (g) by a cross-sectional area D (mm) of the ribbon-like sheet.

Electromagnetic-wave-absorbing sheet

Provided is an electromagnetic-wave interference type electromagnetic-wave absorbing sheet that can favorably absorb electromagnetic waves in a desired frequency band while having high flexibility and light transmittance and being handled easily. The electromagnetic-wave absorbing sheet having flexibility and light transmittance includes an electric resistance film, a dielectric layerand an electromagnetic-wave shielding layerthat each have light transmittance and that are stacked. The electric resistance film is formed of a conductive organic polymer, and the electromagnetic-wave shielding layer has an aperture ratio of 35% or more and 85% or less.

Electromagnetic wave absorbing sheet

The magnetic recording medium disclosed in the present application includes a non-magnetic support, an undercoat layer, a magnetic layer containing magnetic particles, and a back coat layer. The coercive force Hc of the magnetic layer in the thickness direction at 25&#xb0; C. is not 4100 oersteds (Oe) or more, and the coercive force Hc of the magnetic layer in the thickness direction at a temperature between 55&#xb0; C. and 80&#xb0; C. inclusive is not less than 1200 oersteds (Oe) and not more than 3700 oersteds (Oe).

Coating-type magnetic recording medium for heat-assisted recording, and heat-assisted magnetic recording apparatus and heat-assisted magnetic recording method using the same

A refractive index nL and an attenuation rate kL of a magnetic layer are obtained by irradiating linearly polarized light at an irradiation angle of 70&#xb0; from a lengthwise direction of the magnetic layer to the surface of the magnetic layer, and a vertical reflectance RL during vertical incidence of the linearly polarized light in the lengthwise direction is obtained based on nL and kL. A refractive index nT and an attenuation rate kT of the magnetic layer are obtained by irradiating linearly polarized light at an irradiation angle of 70&#xb0; from a width direction of the magnetic layer to the surface of the magnetic layer, and a vertical reflectance RT during vertical incidence of the linearly polarized light in the width direction is obtained from nT and kT. If a variation rate A (%) of RL and RT is A=|RL/RT&#x2212;1|&#xd7;100, the relationship A&#x2264;10% is established.

High recording density magnetic recording medium and recording/reproduction mechanism for the same

Provided is an electromagnetic-wave absorber that can favorably absorb electromagnetic waves of a plurality of different frequencies in a high frequency band equal to or higher than the millimeter-wave band. The electromagnetic-wave absorber includes an electromagnetic-wave absorbing layerin which a plurality of magnetic layers-are stacked, each magnetic layer containing magnetic iron oxide that magnetically resonates at a high frequency in a band equal to or higher than the millimeter-wave band. A value of an anisotropic magnetic field (H) of the magnetic iron oxide contained in at least one of the magnetic layers is different from that of the magnetic iron oxide contained in another of the magnetic layers.

Electromagnetic absorber

In a magnetic recording medium according to the present invention, if a straight line W having a length of 500 nm and a width of 15 nm is displayed parallel to a width direction of the magnetic layer and a straight line L having a length of 500 nm and a width of 15 nm is displayed parallel to a longitudinal direction of the magnetic layer, the number of magnetic particles that intersect the straight line W is N1, and the number of magnetic particles that intersect the straight line L is N2, then, a relationship of N1/0.5&#x3e;60 and N2/0.5&#x3e;60 is established where N1/0.5 is the number of magnetic particles per micrometer obtained by dividing N1 by 0.5 &#x3bc;m and N2/0.5 is the number of magnetic particles per micrometer obtained by dividing N2 by 0.5 &#x3bc;m.

Magnetic recording medium

A magnetic recording medium of the present invention is a magnetic recording medium including a non-magnetic substrate; a non-magnetic layer that is formed on one of principal surfaces of the non-magnetic substrate and contains a non-magnetic powder, a binder, and a lubricant; and a magnetic layer that is formed on a principal surface of the non-magnetic layer opposite to the non-magnetic substrate and contains a magnetic powder and a binder. The magnetic powder has an average particle size between 10 nm and 35 nm inclusive. The lubricant is migratable to the magnetic layer and forms a lubricant layer on a surface of the magnetic layer when a pressure is applied to the magnetic layer. When spacing of the surface of the magnetic layer before and after washing the lubricant with n-hexane is measured with a TSA (Tape Spacing Analyzer), the value of the spacing after washing is 3 to 10 nm, and the value of the spacing before washing is 1 to 5 nm smaller than the value of the spacing after washing.

A magnetic tape driving apparatus, which does not cause damage to either a magnetic head or a magnetic tape when making transition of the magnetic tape from a stopped state to a running state, when making transition of the magnetic tape from a running state to a stopped state, or when reversing the transportation direction of the magnetic tape, is provided. In a state where any one of a magnetic head and a magnetic tape moves and the other rests (i.e., a state where static friction may occur), such as at the time of starting transportation of the magnetic tape, at the time of stopping the tape in a running state, and at the time of reversing the transportation direction of the magnetic tape, a head displacing portion vibrates the magnetic head under the control by a displacement control portion, and thus no static friction occurs between the magnetic head and the magnetic tape. Therefore, the risk of causing damage to the magnetic head (such as an MR head unit equipped with an MR element) or the magnetic tape can be reduced.

Growing community of inventors

Osaka, Japan

Masao Fujita