Abstract: A magnetoresistive audio pickup comprises an audio detection circuit. The audio detection circuit comprises at least one linear magnetoresistive sensor, a coupling capacitance, an AC amplifier, and a signal processing circuit comprising an additional amplifier. The linear magnetoresistive sensor comprises at least one single-axis linear magnetoresistive sensor unit. The linear magnetoresistive sensors are placed in a measurement plane above a speaker's voice coil, the signal output end of each single-axis linear magnetoresistive sensor unit is capacitively coupled to the AC amplifier which provides AC signals through electrical connection to the amplifier, these signals are combined within the signal processing unit into an audio signal, and the audio signal is output from the circuit; each single-axis linear sensor unit is located in the linear response area of the measurement plane.

Abstract: A dual Z-axis magnetoresistive angle sensor comprising a circular permanent magnet encoding disc, two Z-axis magnetoresistive senor chips, and a PCB, two Z-axis magnetoresistive sensors are placed on the PCB. The magnetic sensing directions of the Z-axis magnetoresistive sensors are orthogonal to the substrate. Each Z-axis magnetoresistive sensor chip comprises a substrate and at least one magnetoresistive sensor located on the substrate. The magnetic field sensitive direction of the magnetoresistive sensor is perpendicular to the substrate. The magnetoresistive sensor comprises a flux concentrator and a magnetoresistive sensor unit. The magnetoresistive sensor unit is connected electrically into a push-pull structure. The push arm and pull arm of the magnetoresistive sensor are respectively located at two side positions equidistant from Y-axis central line and above or below the flux concentrator. The circular permanent magnet encoding disc has a magnetization direction parallel to the diameter direction.

Abstract: A single-chip magnetic field sensor bridge, comprising a substrate, a reference arm, a sensing arm, shielding structures, and wire bond pads is disclosed. The reference arm and the sense arm respectively comprise at least two rows/columns of reference element strings and sense element strings formed by electrically connecting one or more identical magnetoresistive sensing elements. The reference element strings and the sense element strings are alternately arranged. The magnetoresistive sensing elements are AMR, GMR or TMR sensing elements. The reference element strings are provided with shielding structures thereon, and the sensing element strings are located in gaps between two adjacent shielding structures. The shielding structures are arrays of elongated strips composed of permalloy or another soft ferromagnetic material. The sensors can be implemented as one of three different bridge structures, called a quasi-bridge, a half-bridge, or a full-bridge.

Abstract: A magnetic anti-counterfeit label and identification system thereof, wherein the magnetic anti-counterfeit label comprises a substrate, a magnetic ink layer, an opaque layer and a protective coating. The magnetic ink layer covers the substrate. The opaque layer covers the magnetic ink layer in order to visually hide the characters, bar code, and other patterns which are printed using magnetic ink. Additionally the protective coating is composed of a polymer or a metal layer, which covers opaque layer. This identification system comprises a magnetic sensor for sensing the magnitude of the magnetic field emitted by the magnetic anti-counterfeit label, a permanent magnet or an electromagnet for magnetizing the magnetic anti-counterfeit label, a digital processing circuit that is electrically connected to the magnetic sensor, and a frame that is used to hold the magnetic sensor and the digital processing circuit. The digital processing circuit outputs a code corresponding to the magnetic anti-counterfeit label.

Abstract: A single magnetoresistor TMR magnetic field sensor chip and magnetic currency detector head; the single magnetoresistor TMR magnetic field sensor chip is installed above a magnetic excitation element; the sensing direction of the chip is parallel to the surface of the chip, and the direction of the magnetic excitation field generated at the chip by the magnetic excitation element is perpendicular to the surface of the chip; the chip comprises a substrate, a magnetic biasing structure deposited on the substrate, a magnetoresistive element, and an input/output terminal; the magnetoresistive element consists of MTJs; the sensing directions of the magnetoresistive element and the MTJs are the same as the sensing direction of the chip; and the direction of a bias magnetic field generated on the chip by the magnetic biasing structure is perpendicular to the sensing direction of the chip. The chip features high sensitivity, high signal-to-noise ratio, small size, high temperature stability and high reliability.

Abstract: A three-axis digital compass comprising two X-axis magnetic sensors, two Y-axis magnetic sensors, a flux concentrator, a signal sampling unit, a signal processing unit, and a signal output unit is disclosed. The X-axis and Y-axis magnetic sensors are arranged along a periphery of the flux concentrator. An external magnetic field is distorted when passing through the flux concentrator. An Z axis component of the external magnetic field is converted into X-axis or Y-axis magnetic field components when passing through the flux concentrator, and the so converted components of the external magnetic field act on the X-axis and Y-axis magnetic sensitive sensors. An output signal of the X-axis and Y-axis magnetic sensitive sensors is sent to the signal processing unit through the signal sampling unit, and it is used to calculate the three orthogonal components of the external magnetic field. These calculated external magnetic field components are output in a digital format through the signal output unit.

Abstract: A single-chip off-axis magnetoresistive Z-X angle sensor and measuring instrument. The single-chip off-axis magnetoresistive Z-X angle sensor comprises a substrate located on an X-Y plane, at least one X-axis magnetoresistive sensor and at least one Z-axis magnetoresistive sensor, the X-axis magnetoresistive sensor and the Z-axis magnetoresistive sensor being located on the substrate. The X-axis magnetoresistive sensor and the Z-axis magnetoresistive sensor each comprise magnetoresistive sensing units and a flux concentrator, the magnetoresistive sensing units being electrically connected into a magnetoresistive bridge comprising at least two bridge arms. The Z-axis magnetoresistive sensor is a push-pull bridge structure, a push arm and a pull arm of the push-pull bridge structure being respectively located at positions equidistant from a Y-axis central line of the flux concentrator.

Abstract: A magnetoresistive mixer, comprising a spiral coil, a bridge-type magnetoresistive sensor and a magnetic shielding layer, wherein the spiral coil is located between the bridge-type magnetoresistive sensor and the magnetic shielding layer. Four tunnel magnetoresistive sensor units forming the bridge-type magnetoresistive sensor respectively contain N array-type magnetic tunnel junction rows. The magnetic tunnel junction rows are connected in series, parallel, or combination of series and parallel connections to form two port structures.

Abstract: A magnetoresistive current limiter, comprising a substrate, a magnetoresistive sensor layer, a first insulating layer, a coil, a second insulating layer, a magnetic shield layer, and an input electrode and output electrode. The coil is located between the magnetic shield layer and the magnetoresistive sensor layer. The first and second insulating layers are isolated from the magnetoresistive sensor layer and the coil, and from the coil and the magnetic shield layer, respectively; the magnetoresistive sensor layer and the coil are connected in series, and are connected to the input electrode and the output electrode.

Abstract: A magnetic currency verification head may include a magnetoresistive sensor chip, and a magnetic bias unit disposed on the side of the magnetoresistive sensor chip away from the detection surface of the magnetic currency verification head, and separated from the magnetoresistive sensor chip; the magnetoresistive sensor chip comprises a gradiometric bridge circuit that includes magnetic sensor elements; the sensitive direction of the magnetic sensor elements is parallel to the detection surface of the magnetic currency verification head; and the magnetic bias unit has a recessed magnetic structure configured such that the magnetic field generated by the magnetic bias unit only has a small magnetic field component in the direction parallel to the detection surface, thereby enabling the magnetic sensor elements to operate in their linear range. As a result, the magnetic currency verification head has high sensitivity and signal-to-noise ratio.

Abstract: The present invention discloses a design and manufacturing method for a single-chip magnetic sensor bridge. The sensor bridge comprises four magnetoresistive elements. The magnetization of the pinned layer of each of the four magnetoresistive elements is set in the same direction, but the magnetization directions of the free layers of the magnetoresistive elements on adjacent arms of the bridge are set at different angles with respect to the pinned layer magnetization direction. The absolute values of the angles of the magnetization directions of the free layers of all four magnetoresistive elements are the same with respect with their pinning layers. The disclosed magnetic biasing scheme enables the integration of a push-pull Wheatstone bridge magnetic field sensor on a single chip with better performance, lower cost, and easier manufacturability than conventional magnetoresistive sensor designs.

Abstract: Provided are a single-chip differential free layer push-pull magnetic field sensor bridge and preparation method, the magnetic field sensor bridge comprising: a substrate, a staggered soft magnetic flux concentrator array, and a GMR spin valve or a TMR magnetoresistance sensing unit array having a magnetic sensing axis in an X-direction on the substrate. A soft magnetic flux concentrator comprises sides parallel to an X-axis and a Y-axis, and four corners sequentially labeled as A, B, C and D clockwise from an upper left position. Magnetoresistive sensing units are located at gaps between the soft magnetic flux concentrators. Additionally, the magnetoresistive sensing units corresponding to the A and C corner positions and B and D corner positions of the soft flux concentrators are defined as push magnetoresistive sensing units and pull magnetoresistive sensing units respectively.

Abstract: This invention discloses a TMR near-field magnetic communication system, which is used for detecting AC and DC magnetic fields generated by a near-field magnetic communication system, and inputting AC and DC magnetic field signal to an audio electroacoustic taking the same as input signals thereof. The audio electroacoustic device comprises a hearing aid, an earphone of a home entertainment system, a public hearing loop system with an embedded hearing device, etc. The TMR near-field magnetic communication system comprises one or more TMR sensor bridges for detecting AC and DC magnetic field signals, an analog-signal circuit containing a filter which is used for separating components of AC and DC signals output by a TMR sensor, an amplifier which is used for amplifying an AC electrical signal, and an analog output used for transmitting the AC electrical signal to the audio electroacoustic device.

Abstract: The present invention relates to a permanent magnet suitable for a magnetic angle encoder. The permanent magnet has an annular cylindrical structure and comprises a first permanent magnet unit and a second permanent magnet unit. The first permanent magnet unit and the second permanent magnet unit are geometrically symmetrical with respect to a diametral cross section. The magnetization intensity of the first permanent magnet unit and the magnetization intensity of the second permanent magnet unit are parallel to the axial direction of the annular cylinder and are in opposite directions, or the magnetization intensity of the first permanent magnet unit and the magnetization intensity of the second permanent magnet unit are perpendicular to the diametral cross section and are parallel to one another and in the same direction.

Abstract: A magnetoresistive Z-axis gradient sensor chip, which is used to detect the gradient in the XY plane of a Z-axis magnetic field component generated by a magnetic medium; the sensor chip comprises a Si substrate, a collection of two or two groups of flux guide devices separated a distance Lg and an arrangement of electrically interconnected magnetoresistive sensor units. The magnetoresistive sensor units are located on the Si substrate and located above or below the edge of the flux guide devices as well; the flux guide devices convert the component of the Z-axis magnetic field into the direction parallel to the surface of the Si substrate along the sensing axis direction of the magnetoresistive sensing units. The magnetoresistive sensor units are electrically interconnected into a half bridge or a full bridge gradiometer arrangement, wherein the opposite bridge arms are separated by distance Lg. This sensor chip can be utilized with a PCB or in combination with a PCB plus back-bias magnet with casing.

Abstract: A magnetic anti-counterfeit label and identification system thereof, wherein the magnetic anti-counterfeit label comprises a substrate, a magnetic ink layer, an opaque layer and a protective coating. The magnetic ink layer covers the substrate. The opaque layer covers the magnetic ink layer in order to visually hide the characters, bar code, and other patterns which are printed using magnetic ink. Additionally the protective coating is composed of a polymer or a metal layer, which covers opaque layer. This identification system comprises a magnetic sensor for sensing the magnitude of the magnetic field emitted by the magnetic anti-counterfeit label, a permanent magnet or an electromagnet for magnetizing the magnetic anti-counterfeit label, a digital processing circuit that is electrically connected to the magnetic sensor, and a frame that is used to hold the magnetic sensor and the digital processing circuit. The digital processing circuit outputs a code corresponding to the magnetic anti-counterfeit label.

Abstract: A single chip push-pull bridge-type magnetic field sensor. The sensor comprises a substrate, bonding pads, magnetoresistance sensing elements, and flux concentrators, wherein the magnetoresistance sensing elements are positioned in the clearances of the adjacent flux concentrators, and the directions of the pinning layers of the magnetoresistance sensing elements are identical. The flux concentrators are divided into a push arm type and a pull arm type, the included angle between one type and an X-axis forward direction is positive, and the included angle between the other type and the X-axis forward direction is negative. The working principle of the sensor is that the magnetic field along the X-axis direction in the clearances of the flux concentrators are oppositely oriented. The sensor has the advantages of small size, low cost, simplicity in manufacturing, high sensitivity, good linearity, high sensitivity, wide working dynamic range, and the like.

Abstract: A coin detection system comprises an excitation coil, a radial magnetic gradiometer, an axial magnetic gradiometer, a signal excitation source, a drive circuit, an analog front-end circuit and a processor. After the excitation coil is excited by the signal excitation source and the drive circuit, the excitation coil generates an excitation magnetic field parallel to the axial direction of a coin, and under the influence of the excitation magnetic field, the coin generates an induced magnetic field through eddy currents induced in the coin; the radial magnetic gradiometer and the axial magnetic gradiometer detect the magnetic field components of the magnetic field in the radial direction and the axial direction of the coin, and the detected signal is transmitted to the analog front-end circuit for amplification; the processor processes and then outputs the amplified signal transmitted by the analog front-end circuit, and the material, design, denomination, etc.

Abstract: Disclosed is a low fly height in-plane magnetic image sensor chip. This sensor chip comprises a Si substrate with a pit on the surface, a magnetoresistive sensor, and an insulating layer. The magnetoresistive sensor is located on the bottom surface of the pit in the Si substrate. The insulating layer is located above the magnetoresistive sensor. The magnetic image surface detected during operation is coplaner or parallel with the surface of the Si substrate surface. The input and output ends of the magnetoresistive sensor are connected with leads directly, or bonded with leads through pads, or through a conducting post and pads to form connections. And the flying height of the leads is lower than the height of the surface of the Si substrate. This technical solution has several advantages, such as compact structure, high output signal, and direct contact with the magnetic image.

Abstract: A monolithic three-axis magnetic field sensor and its manufacturing method, the sensor comprises an X-axis sensor, a Y-axis sensor and a Z-axis sensor integrated into the same substrate, wherein the X-axis sensor and the Y-axis have the same structure, that is, both are referenced bridge structures. The magnetoresistive sensing elements of the reference arm are placed beneath the corresponding magnetic flux guides, and the magnetoresistive sensing elements are placed in the gaps between the corresponding magnetic flux guides. However the magnetoresistive elements of these two sensors are aligned perpendicular to each other, and the magnetization directions of the pinned layer of these magnetoresistive elements are perpendicular to each other as well. The Z-axis sensor is a push-pull bridge structure, the push arms and pull arms of the magnetoresistive sensors are respectively aligned above or beneath the edges of the magnetic flux guides.