Abstract: A rotation detection apparatus for detecting a rotation state of a gear is disclosed. The rotation detection apparatus includes a magnetic sensor, a magnetic filed generation unit, and a self-diagnosis unit. The sensor includes: a bias magnet for generating a bias magnetic field extending toward the gear; and a magnetic-electric conversion element for sensing the bias magnetic field acting thereon. When the gear is in a stationary state, the magnetic filed generation unit generates a diagnosis use magnetic field extending toward the magnetic-electric conversion element. The self-diagnosis unit determines whether the magnetic sensor has a failure based on an output from the magnetic-electric conversion element that is subjected to the bias magnetic field and the self-diagnosis use magnetic field.

Abstract: In the normal rotation direction, a change in the main sensing signal caused by a front edge is defined as a signal change caused by an effective edge, and a change in the main sensing signal caused by a back edge is defined as a signal change caused by an ineffective edge. In the reverse direction, a change in the main sensing signal caused by the back edge is defined as a signal change caused by an effective edge, and a change caused by a front edge is defined as a signal change caused by an ineffective edge. Regardless of the rotation direction, a detection signal generating circuit generates a detection signal including falling-edge changes and rising edge changes caused by the effective edge and ineffective edge respectively. When the direction is changed, the signal change on the detection signal is prohibited. As a result, gear tooth detection discrepancies are prevented.

Abstract: A rotation sensor includes: a magnetism generator; a sensor chip having a magneto-resistance element region and a Hall element region; and a detection circuit for detecting a relative rotation angle with reference to the magnetism generator according to output signals from each magneto-resistance element and each Hall element to detect. A phase difference is provided between output signals from the magneto-resistance elements. A phase difference is provided between output signals from the Hall elements. The magneto-resistance element region and the Hall element region at least partially overlap with each other. The detection circuit includes a comparison section, an angle computing section, and an output section. The comparison section compares an output level from each Hall element with a predetermined threshold value level, and provides a comparison result for each Hall element.

Abstract: In the normal rotation direction, a change in the main sensing signal caused by a front edge is defined as a signal change caused by an effective edge, and a change in the main sensing signal caused by a back edge is defined as a signal change caused by an ineffective edge. In the reverse direction, a change in the main sensing signal caused by the back edge is defined as a signal change caused by an effective edge, and a change caused by a front edge is defined as a signal change caused by an ineffective edge. Regardless of the rotation direction, a detection signal generating circuit generates a detection signal including falling-edge changes and rising edge changes caused by the effective edge and ineffective edge respectively. When the direction is changed, the signal change on the detection signal is prohibited. As a result, gear tooth detection discrepancies are prevented.

Abstract: A rotation detection apparatus for detecting a rotation state of a gear is disclosed. The rotation detection apparatus includes a magnetic sensor, a magnetic filed generation unit, and a self-diagnosis unit. The sensor includes: a bias magnet for generating a bias magnetic field extending toward the gear; and a magnetic-electric conversion element for sensing the bias magnetic field acting thereon. When the gear is in a stationary state, the magnetic filed generation unit generates a diagnosis use magnetic field extending toward the magnetic-electric conversion element. The self-diagnosis unit determines whether the magnetic sensor has a failure based on an output from the magnetic-electric conversion element that is subjected to the bias magnetic field and the self-diagnosis use magnetic field.

Abstract: Magnetoresistive devices are formed on the insulating surface of a substrate made of silicon. The devices are connected in series through an insulating film using a wiring layer formed on the surface of the substrate. An insulating film for passivation is formed to cover the devices and the wiring layer. A magnetic shield layer of Ni—Fe alloy is formed on the passivation insulating film through an organic film for relieving thermal stress to cover one of the devices. After removal of the sensor chip containing the magnetoresistive devices and other components from the wafer, the chip is bonded to a lead frame through an Ag paste layer by heat treatment. Preferably, the magnetic shield layer is made of a Ni—Fe alloy having a Ni content of 69% or less.

Abstract: A rotation detecting device includes a magnetoresistive unit comprising a pair of magnetoresistive sensing elements arranged in line symmetry, and a biasing magnet that generates magnetic flux. The magnetoresistive unit is arranged so that its line of symmetry extends in the direction of the magnetic flux generated by the biasing magnet. As a result, an output of the magnetoresistive unit does not change when the magnetic flux passes along the line of symmetry whether operating in a high temperature condition or a room temperature condition. By setting the threshold level to this output voltage, the output of the magnetoresistive unit can be shaped into a pulse signal without changing it in correspondence with temperatures.

Abstract: In a position detecting device for a rotor, such as a camshaft gear, a magnet sensor is constructed of first, second, third, and fourth MRE bridges. The bridges are positioned symmetric to a magnetic axis of a bias magnet. The third bridge is arranged at a midpoint between the first bridge and the magnetic axis. The fourth bridge is arranged at a midpoint between the second bridge and the magnetic axis. Outputs of the bridges are inputted to a differential amplifier circuit to obtain a single differential output. A position of the rotor is determined based on the differential output, regardless of gear-teeth shapes of the rotor.

Abstract: The present invention provides a magnetic sensor adjusting method that can always be accurate in sensing a sensing target satisfactorily irrespective of fluctuations of a sensing gap length that may occur between different magnetic sensor products or in one magnetic sensor product, and that can prevent from occurring an irregularity of a phase of a binarized waveform edge. Within a magnetic gap of the magnetic sensor, a sensing gap length formed between a concave and convex portions of a sensing target units and a magnetic filed detecting sections is changed among a plurality of setting values. Then, the magnetic filed detecting sections 3, 5 obtain detection waveforms 201, 202 in every setting values of the sensing gap length. Next, an intersection point level value AG0 obtained by superimposing the plurality of detection waveforms in phase is calculated. Then, a threshold value VTH is adjusted so as to agree with the calculated intersection point level value AG0.

Abstract: The present invention provides a magnetic sensor adjusting method that can always be accurate in sensing a sensing target satisfactorily irrespective of fluctuations of a sensing gap length that may occur between different magnetic sensor products or in one magnetic sensor product, and that can prevent from occurring an irregularity of a phase of a binarized waveform edge. Within a magnetic gap of the magnetic sensor, a sensing gap length formed between a concave and convex portions of a sensing target units and a magnetic filed detecting sections is changed among a plurality of setting values. Then, the magnetic filed detecting sections 3, 5 obtain detection waveforms 201, 202 in every setting values of the sensing gap length. Next, an intersection point level value AG0 obtained by superimposing the plurality of detection waveforms in phase is calculated. Then, a threshold value VTH is adjusted so as to agree with the calculated intersection point level value AG0.

Abstract: Magnetoresistive devices are formed on the insulating surface of a substrate made of silicon. The devices are connected in series through an insulating film using a wiring layer formed on the surface of the substrate. An insulating film for passivation is formed to cover the devices and the wiring layer. A magnetic shield layer of Ni—Fe alloy is formed on the passivation insulating film through an organic film for relieving thermal stress to cover one of the devices. After removal of the sensor chip containing the magnetoresistive devices and other components from the wafer, the chip is bonded to a lead frame through an Ag paste layer by heat treatment. Preferably, the magnetic shield layer is made of a Ni—Fe alloy having a Ni content of 69% or less.

Abstract: In a revolution detecting device, a tunneling magnetoresistance sensor having an element located in a region is provided. The tunneling magnetoresistance sensor comprises a substrate, a pinned layer composed of ferromagnetism material and located to one side of the substrate, a tunneling layer composed of insulating film and located to one side of the pinned layer and a free layer composed of ferromagnetism film and located to one side of the tunneling layer. The element is configured to detect a change of magnetoresistance of the element according to a magnetic field applied in the region in which the element is located. The change of the magnetoresistance of the element is based on a change of current flowing through the tunneling layer between the pinned layer and the free layer. In the revolution detecting device, a revolution member is disposed in a vicinity of the element in the Y axis from a viewpoint of the element. The revolution member has a surface portion opposite to the element.

Abstract: Magnetoresistive devices are formed on the insulating surface of a substrate made of silicon. The devices are connected in series through an insulating film using a wiring layer formed on the surface of the substrate. An insulating film for passivation is formed to cover the devices and the wiring layer. A magnetic shield layer of Ni—Fe alloy is formed on the passivation insulating film through an organic film for relieving thermal stress to cover one of the devices. After removal of the sensor chip containing the magnetoresistive devices and other components from the wafer, the chip is bonded to a lead frame through an Ag paste layer by heat treatment. Preferably, the magnetic shield layer is made of a Ni—Fe alloy having a Ni content of 69% or less.

Abstract: In a position detecting device for a rotor, such as a camshaft gear, a magnet sensor is constructed of first, second, third, and fourth MRE bridges. The bridges are positioned symmetric to a magnetic axis of a bias magnet. The third bridge is arranged at a midpoint between the first bridge and the magnetic axis. The fourth bridge is arranged at a midpoint between the second bridge and the magnetic axis. Outputs of the bridges are inputted to a differential amplifier circuit to obtain a single differential output. A position of the rotor is determined based on the differential output, regardless of gear-teeth shapes of the rotor.

Abstract: In a revolution detecting device, a tunneling magnetoresistance sensor having an element located in a region is provided. The tunneling magnetoresistance sensor comprises a substrate, a pinned layer composed of ferromagnetism material and located to one side of the substrate, a tunneling layer composed of insulating film and located to one side of the pinned layer and a free layer composed of ferromagnetism film and located to one side of the tunneling layer. The element is configured to detect a change of magnetoresistance of the element according to a magnetic field applied in the region in which the element is located. The change of the magnetoresistance of the element is based on a change of current flowing through the tunneling layer between the pinned layer and the free layer. In the revolution detecting device, a revolution member is disposed in a vicinity of the element in the Y axis from a viewpoint of the element. The revolution member has a surface portion opposite to the element.

Abstract: Magnetoresistive devices are formed on the insulating surface of a substrate made of silicon. The devices are connected in series through an insulating film using a wiring layer formed on the surface of the substrate. An insulating film for passivation is formed to cover the devices and the wiring layer. A magnetic shield layer of Ni—Fe alloy is formed on the passivation insulating film through an organic film for relieving thermal stress to cover one of the devices. After removal of the sensor chip containing the magnetoresistive devices and other components from the wafer, the chip is bonded to a lead frame through an Ag paste layer by heat treatment. Preferably, the magnetic shield layer is made of a Ni—Fe alloy having a Ni content of 69% or less.

Abstract: A rotation detecting device includes a magnetoresistive unit comprising a pair of magnetoreistive sensing elements arranged in line symmetry, and a biasing magnet that generates magnetic flux. The magnetoresistive unit is arranged so that its line of symmetry extends in the direction of the magnetic flux generated by the biasing magnet. As a result, an output of the magnetoresitive unit does not change when the magnetic flux passes along the line of symmetry whether operating in high temperature condition or room temperature condition. By setting the threshold level to this output voltage, the output of the magnetoresistive unit can be shaped into a pulse signal without changing it in correspondence with temperatures.

Abstract: In a position detecting device for a moving object, such as a camshaft gear, having ridges and valleys, magnetoresistive elements are disposed in positions offset in the rotation direction of the moving object from the magnetic center of a bias magnetic field projected by a bias magnet. The direction of the bias magnetic field is different when the moving object is in a ridge position from when it is in a valley position. A mid-point potential of the MREs is taken as the output of an MRE bridge to obtain an output value which is different when the moving object is in the ridge position from when it is in the valley position. It is thus possible to distinguish between the ridge position and the valley position of the moving object.

Abstract: Rotation of a rotating object such as a toothed rotor is detected based on put potentials of a bridge circuit having four magnetoresistive elements. The bridge circuit formed on an integrated circuit chip is positioned in a biasing magnetic field generated by a magnet disposed at a vicinity of the toothed rotor. A pair of magnetoresistive elements form a first circuit in the bridge while the others pairs forms a second circuit. To cancel influence of magnetostrictive effects due to an external force imposed on the integrated circuit chip, the first and second circuits in the bridge are positioned symmetrically to each other with respect to a center line of the biasing magnetic field.

Abstract: A magnetoresistance element detects an angular position of a toothed gear rotated by an engine. The element (first element) is positioned at a vicinity of the peripheral edge of the gear tooth in a magnetic filed supplied from a bias magnet. The magnetic field direction is changed by the tooth, which is detected by the element even when the gear is not rotated before the engine starts. To detect an exact angle of the gear, an additional magnetoresistance element positioned perpendicularly to the first element may be used. The gear tooth position is detected by the first element even when the gear is not rotated, and once the gear rotates, the second element detects an exact angular position of the gear.