| 摘要 |
PURPOSE:To obtain a magnetic sensor capable of sufficiently satisfying miniaturization, especially, the demand for a narrow track, by a method wherein a boundary part is provided to an increment phase in the circumferential direction thereof and magnetic poles different in axial direction are formed in opposed relationship through said boundary part. CONSTITUTION:A spiral boundary part 11 is provided to an increment phase 5 in the circumferential direction thereof and the increment phase 5 is divided into an upper phase 5a and a lower phase 5b, while the magnetic poles constituting both phases are formed so that magnetic poles different from each other are opposed in the axial direction of a rotary drum 1 through the boundary part 11. Herein, magnetosensitive elements for a Z-phase are pref. arranged corresponding to a spiral angle theta. By this method, since the Z-phase is constituted at the boundary part 11, the signals corresponding to the Z-phase and the increment phase 5 can be outputted. Further, each of the magnetosensitive elements corresponding to the Z-phase faces to the boundary part 11 two times during one revolution of the drum 1, but since the magnetosensitive elements are arranged corresponding to the spiral angle theta, magnetoresistance effect appears only once.
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