Abstract: A position detection apparatus including a detection unit for an absolute track including a plural number of ABS heads for absolute track, in which the separation between neighboring heads is broadened. The n ABS heads 10-1 to 10-n are arrayed to satisfy the following equations 1 and 2 when n is an even number and the following equations 1 and 3 when n is an odd number: &lgr;1=m&lgr;, m being an integer not less than 2  (1) &lgr;1≠k(2n/2+1)&lgr;, k being a natural number  (2) &lgr;1≠k(2n+1)&lgr;  (3). By arraying the ABS heads 10-1 to 10-n under these conditions, the separation between neighboring ones of the ABS heads 10-1 to 10-n can be 2&lgr; or larger.

Abstract: A position detection apparatus including a detection unit for an absolute track including a plural number of ABS heads for absolute track, in which the separation between neighboring heads is broadened.

Abstract: There is provided a position transducer (1) capable of accurately detecting an n-bit code by n ABS detectors from one ABS track. When an INC value is under j or over k, signal output from each of the ABS detectors is binarized based on a threshold h and also based on a threshold l. First, an ABS value decider (24) decides that a bit is “H” when it has been judged as being “H” on the basis of both the thresholds and a bit is “L” when it is has been judged as being “L” on the basis of both the thresholds. When the INC value is under j, a lower bit has the same code as that of the deiced bit. So, the ABS value decider (24) decides that the lower bit is “H” or “L”. On the other hand, when the INC value is over k, an upper bit has the same code as the decided code. Thus, the ABS value decider (24) decides that the upper bit is “H” or “L”.

Abstract: Two sensors are provided on a clutch core. Sensor coils are driven at a high frequency by a high-frequency driving circuit. As the sensors sense a magnetic flux of a magnetic circuit including the clutch core and an armature, the impedance of the sensor coils changes. In accordance with the outputs from the sensor coils at this point, an impedance detecting circuit detects the impedance of the sensor coils. Then, an impedance combining circuit combines the impedance of the sensor coils. On the basis of the combined impedance, a current control circuit controls a current supplied to an exciting coil. Thus, the attracting force of the armature to the core excited by the exciting coil is controlled.

Abstract: A position transducer capable of accurately detecting an n-bit code by a small number of ABS detectors when there is provided one ABS track. In an ABS head, the ABS detectors 101 to 10n+m are disposed for a distance &lgr;1 between the first ABS detector 101 and (n+m)th ABS detector 10n+m to satisfy a requirement (n−1)&lgr;+2&dgr;<&lgr;1 and a distance &lgr;2 between two successive ones of the ABS detectors to satisfy a requirement 2&dgr;<&lgr;2<&lgr;−2&dgr;, so that at least one ABS detector is opposite to a stable area T in each of micro-areas at n successive bits.

Abstract: There is provided a position transducer (1) capable of accurately detecting an n-bit code by n ABS detectors from one ABS track. When an INC value is under j or over k, signal output from each of the ABS detectors is binarized based on a threshlold h and also based on a threshold l. First, an ABS value decider (24) decides that a bit is “H” when it has been judged as being “H” on the basis of both the thresholds and a bit is “L” when it is has been judged as being “L” on the basis of both the thresholds. When the INC value is under j, a lower bit has the same code as that of the deiced bit. So, the ABS value decider (24) decides that the lower bit is “H” or “L”. On the other hand, when the INC value is over k, an upper bit has the same code as the decided code. Thus, the ABS value decider (24) decides that the upper bit is “H” or “L”.

Abstract: Two sensors are provided on a clutch core. Sensor coils are driven at a high frequency by a high-frequency driving circuit. As the sensors sense a magnetic flux of a magnetic circuit including the clutch core and an armature, the impedance of the sensor coils changes. In accordance with the outputs from the sensor coils at this point, an impedance detecting circuit detects the impedance of the sensor coils. Then, an impedance combining circuit combines the impedance of the sensor coils. On the basis of the combined impedance, a current control circuit controls a current supplied to an exciting coil. Thus, the attracting force of the armature to the core excited by the exciting coil is controlled.

Abstract: A sensor coil is provided on a core which forms a magnetic circuit for driving a linear motor, and the core is excited by electrifying the sensor coil at a high frequency. The high-frequency excitation is carried out in such a manner that the sensor coil is not magnetically saturated, and an eddy current is generated in the core. The impedance of the sensor coil is detected in this state and the quantity of a magnetic flux generated in the core constituting the magnetic circuit is detected on the basis of the impedance. Thus, the influence on the magnetic circuit itself is reduced and higher accuracy, miniaturization and lower power consumption are realized.

Abstract: A magnetic metal sensor having a high response speed and which can detect small-sized metal pieces and can elongate the separation from the metal pieces. A magnetic metal sensor 2 has a core 22 defining a substantially U-shaped open magnetic path and coils 23, 24 of the same polarity mounted on the core 22. A uniform magnetic field along the direction of magnetic sensitivity is applied by a magnet 25 across the coils 24, 24. If magnetic metal approaches to a open magnetic path portion of the core 22 of the magnetic metal sensor 2, the magnetic reluctance of the magnetic circuit formed by the core and air is changed, as a result of which the impedance of the cores 23, 24 is changed. The magnetic metal sensor 2 detects the possible presence of magnetic metal or its displacement based on impedance changes of the paired coils 23, 24.

Abstract: A magneto-resistive effect sensor capable of outputting a sufficient output of optimum characteristics even if a magnetized surface of a magnetized material is curved, arcuately- or polygonally-shaped. On the magneto-resistive effect sensor 3, plural magnetically sensitive portions 12a to 12d of the same shape are formed and arrayed parallel to one another, while being electrically connected in series to permit the current i to flow through the electrically connected magnetically sensitive portions. The magnetically sensitive portion 12a is made up of a mid portion 15a having a width w1 and ends having a width w2. A signal magnetic field of different strengths is applied from the magnetized material along the current flowing direction. The widths w1 and w2 differ with the strengths of the applied signal magnetic field and are of a ratio such that w1:w2=2:3.

Abstract: A displacement detecting apparatus includes an error correcting circuit through which a pair of sine wave signals detected by a detecting head unit are corrected. A signal detecting circuit receives the pair of sine wave signals whose phases are shifted by about 90.degree., and detects a magnitude of one of the two sine wave signal when the other one of the two sine wave signals crosses with a reference voltage level. The error correcting circuit calculates an error correction amount of each sine wave signal according to the detected magnitude of the signal and eliminates the calculated error correction amount from the signals. Therefore, the sine wave signals of position information are accurately corrected in direct-current component, voltage ratio and phase difference.

Abstract: A position detecting apparatus can detect a position with high accuracy even when a relative angle between a magnetic recording medium and a magnetic detecting portion is fluctuated, when an angle of the magnetic recording medium is partly fluctuated or even when an ambient temperature and a temperature of the magnetic detecting portion are fluctuated. The position detecting apparatus includes a magnetic recording medium (1) in which magnetic information is recorded and a magnetic detecting portion (2) movable relative to the magnetic recording medium (1) and which detects the magnetic information recorded on the magnetic recording medium (1). The magnetic detecting portion (2) includes a plurality of, for example, m magnetoresistance effect elements (3) with an artificial grid film structure wherein conductive layers (3a) and magnetic layers (3b) are alternately laminated. The magnetoresistance effect elements (3.sub.1, 3.sub.2, . . . , 3.sub.

Abstract: A magnetic sensor is disposed in an opposing relation to a magnetic scale in which a flat surface scale base made of a glass is plated by a magnetic material and a resultant plated layer is magnetized at a constant grating pitch. The magnetic sensor includes two magnetoresistance effect element groups disposed symmetrically with respect to a common central line. Since the surface of the magnetic scale is smooth, a clearance between the magnetic sensor and the magnetic scale can be kept substantially constant. When the magnetic sensor is moved in an opposing relation to the magnetic scale, a rise of temperature in the magnetoresistance effect elements is compensated for by the above symmetrical layout of the two magnetoresistance effect element groups.