MAGNETICALLY-DETECTING ENCODER

PROBLEM TO BE SOLVED: To provide a magnetically-detecting encoder for following a rotation of a rotating magnet, obtaining an accurate detection output, and reducing a thickness. SOLUTION: The rotating magnet 16 is magnetized so as to alternately change magnetic poles on an outer circumference 16a in the rotational direction. A detecting element 19 faces the outer circumference 16a, and has a magnetoresistance effect element with a fixed magnetic layer and a free magnetic layer. A vector for indicating the direction (the P-direction) of a fixed magnetization in the fixed magnetic layer and a vector of a magnetization in the free magnetic layer are located in a plane orthogonal to a central axis O of the rotating magnet 16. When the rotating magnet 16 rotates, the detection output corresponding to a rotational angle of the vector of the magnetization in the free magnetic layer is obtained. Thereby, the accurate detection output can be obtained without being affected by the fluctuation in a strength of a leakage magnetic field from the rotating magnet 16. COPYRIGHT: (C)2010,JPO&INPIT