Patent ID: 6452381
Filing Date: 2002-09-17
Classification: G01D

Abstract:
A position detecting device comprising:a moving object having a ridge and a valley arranged alternately thereon; a bias magnet for projecting a bias magnetic field toward the ridge and the valley of the moving object; and a resistive element group including at least one magnetoresistive element disposed between the moving object and the bias magnet, and responsive to a change in direction of the bias magnetic field caused by movement of the moving object, wherein the resistive group including at least one magnetoresistive element is disposed in a position offset in a moving direction of the moving object from a magnetic center of the bias magnetic field corresponding to a center axis of the bias magnet in order that an output signal of the resistive element group produced when the ridge of the moving object faces the bias magnet is different in signal level from an output signal of the resistive element group produced when the valley of the moving object faces the bias magnet in a stationary state of the moving object, wherein the resistive element group including at least one magnetoresistive element includes a first magnetoresistive element and a second magnetoresistive element, and the first and second magnetoresistive elements are formed on a surface of a substrate that is arranged substantially in parallel with the moving direction of the moving object, and wherein the first and second magnetoresistive elements are connected in series and arranged so that a center axis therebetween is laterally offset from and parallel to the magnetic center of the bias magnetic field.