METAL FOREIGN SUBSTANCE DETECTION DEVICE, WIRELESS POWER SUPPLY DEVICE, WIRELESS POWER RECEIVING DEVICE, AND WIRELESS POWER TRANSMISSION SYSTEM

PROBLEM TO BE SOLVED: To reduce a possibility that detection of a metal foreign substance is failed.SOLUTION: A metal foreign substance detection device 14A comprises: a sensor part S including at least one antenna coil L3 that receives a magnetic field or a current and generates a vibration signal Vb; a vibration time length measuring circuit 145 for measuring a vibration time length TL indicating a length of the time required for vibrating the vibration signals Vc outputted from the sensor part S for predetermined waves that are greater than one; and a discrimination circuit 146 for discriminating the presence/absence of a metal foreign substance that approaches the antenna coil L3, on the basis of the vibration time length TL and a vibration time length TL under the absence of the metal foreign substance approaching the antenna coil.SELECTED DRAWING: Figure 3 【課題】金属異物の検出に失敗する可能性を低減する。【解決手段】金属異物検出装置１４Ａは、磁界または電流を受けて振動信号Ｖｂを発生する少なくとも１つのアンテナコイルＬ３を有するセンサ部Ｓと、１より大きい所定波数分のセンサ部Ｓから出力される振動信号Ｖｃの振動に要する時間の長さを示す振動時間長ＴＬを計測する振動時間長計測回路１４５と、振動時間長ＴＬと接近する金属異物が無いときの振動時間長ＴＬである基準時間長ＣＴＬとに基づいて、アンテナコイルＬ３に接近する金属異物の有無を判定する判定回路１４６と、を備えることを特徴とする。【選択図】図３