| 摘要 |
PURPOSE:To detect moving speed accurately by creating an output signal corresponding to the resistance of a magneto resistance element, which varies according to the relative position between a magnet and the magnetic resistance element, and then differentiating thus produced output signal and producing a speed corresponding to the moving speed. CONSTITUTION:When an arm 6 is moved by a rotary force produced through a driving coil 11, relative position between a detection magnet 14 and an MR element 15 varies. The relative positional displacement X causes variation of the intensity of magnetic field traversing the MR element 15 thus varying the resistances R1, R2 in the MR element 15. When a bias voltage E1 is applied on the MR element variation of the resistances R1, R2 can be detected based on an MR element detecting voltage E2. Consequently position of an actuator 7 can be detected based on the MR element detection voltage E2. Since the speed is detected through differentiation of a position signal, it can be determined through differentiation of the MR element detection voltage E2. Furthermore, since the MR element is composed of a semiconductor element, the size of the MR element can be reduced. |
