MAGNETIC FIELD DETECTOR

• Main Author: UCHIYAMA TAKESHI
• Format: Patent
• Language: English; Japanese
• Published: 30.03.2017
• Subjects: MEASURING; MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES; PHYSICS; TESTING

PROBLEM TO BE SOLVED: To provide a magnetic field detector capable of accurately detecting a magnetic field without using a magnetic shield.SOLUTION: A magnetic field detector comprises a pair of a measurement magnetic sensor 14a and a reference magnetic sensor 14b for detecting magnetism, and detects a magnetic field by differentially operating outputs of the pair of magnetic sensors 14a, 14b by use of an operation amplifier 44. The magnetic field detector further comprises: a feedback coil 20 capable of applying a common magnetic field Bf to the pair of magnetic sensors 14a, 14b; and a feedback circuit 60 for supplying an electric current to the feedback coil 20 based on an output Vout_b of the reference magnetic sensor 14b of the pair of magnetic sensors 14a, 14b. When the detector differentially operates the outputs of the pair of magnetic sensors 14a, 14b so as to detect the magnetic field ΔB of a measured object, the detector can detect the magnetic field at the pair of magnetic sensors 14a, 14b by considering the magnetic field Bf applied by the feedback coil 20.SELECTED DRAWING: Figure 2 【課題】磁気シールドを用いることなく精度のよい磁界検出を可能とする磁界検出装置を提供する。【解決手段】磁気を検出するための一対の測定用磁気センサ１４ａおよび参照用磁気センサ１４ｂを有し、作動アンプ４４により一対の磁気センサ１４ａ、１４ｂの出力を差動させて磁界の検出を行なうものであって、一対の磁気センサ１４ａ、１４ｂに共通する磁界Ｂｆを印加可能なフィードバックコイル２０と、前記一対の磁気センサ１４ａ、１４ｂのうちの参照用磁気センサ１４ｂの出力Ｖｏｕｔ＿ｂなどに基づいてフィードバックコイル２０に電流を供給するフィードバック回路６０とをさらに有する。一対の磁気センサ１４ａ、１４ｂの出力を差動させて測定対象の磁界ΔＢの検出を行なう際に、前記フィードバックコイル２０によって印加される磁界Ｂｆを考慮して、一対の磁気センサ１４ａ、１４ｂにおいて磁界の検出を行うことができる。【選択図】図２