| 摘要 |
PURPOSE:To obtain a magnetism detector whose detecting function is raised, by constituting a housing by use of a magnetic metal having a high magnetic permeability and performing magnetic shielding to a magneto-resistance element. CONSTITUTION:A flat housing 36 which cuts a corner of the left and right upper end part and has a hexagonal shape in elevation view is obtained by forming a magnetic metallic plate such as permalloy, etc. by a press, and an opening part 36a provided on the upper face is closed by a protecting plate 37 consisting of a thin film made of a non-magnetic metal such as phosphor bronze, etc. Magneto-resistance elements 32, 33 are provided in parallel on the left and right so as to have a suitable interval to the protecting plate 37. A sensor unit 30 obtained by forming two elements 32, 33 on a ferromagnetic material 39 such as ferrite, etc. is fixed onto the upper face of a substrate 38 consisting of an insulating material. In this way, since the magneto-resistance element is magnetically shielded by the housing made of a magnetic metal, it is scarcely influenced by an external magnetic field, and magnetism can be detected with high sensitivity through the protecting plate 37 of a non-magnetic material. |
