TOUCH SWITCH SYSTEM AND TOUCH DETECTION METHOD FOR TOUCH SWITCH SYSTEM

To provide a touch switch system that can improve touch detection accuracy even in the presence of noise.SOLUTION: The touch switch system includes: a signal reception section 501 for receiving a sine wave component and a cosine wave component from a conversion section 50A; an offset signal determination section 502 for determining a sine wave offset signal and a cosine wave offset signal on the basis of a first sine wave component and a first cosine wave component when a drive AC current does not flow to a drive electrode and an offset coefficient; a difference calculation section 503 for calculating a sine wave difference between a second sine wave component when the drive AC current flows to the drive electrode and the sine wave offset signal and calculating a cosine wave difference between a second cosine wave component when the drive AC current flows to the drive electrode and the cosine wave offset signal; an effective value calculation section 504 for calculating an effective value of a differential signal from the sine wave difference and the cosine wave difference; and a touch detection section 505 for detecting a touch on a switch section on the basis of the effective value of the differential signal.SELECTED DRAWING: Figure 4 【課題】ノイズ存在下においてもタッチ検出精度を向上可能なタッチスイッチシステムを提供する。【解決手段】変換部５０Ａからの正弦波成分及び余弦波成分を受信するための信号受信部５０１と、駆動電極への駆動交流電流未通流時の第１正弦波成分及び第１余弦波成分とオフセット係数とに基づいて、正弦波オフセット信号及び余弦波オフセット信号を決定するためのオフセット信号決定部５０２と、駆動電極への駆動交流電流通流時の第２正弦波成分と正弦波オフセット信号との正弦波差分を算出するとともに、駆動電極への駆動交流電流通流時の第２余弦波成分と余弦波オフセット信号との余弦波差分を算出するための差分算出部５０３と、正弦波差分及び余弦波差分から差分信号の実効値を算出するための実効値算出部５０４と、差分信号の実効値に基づいてスイッチ部へのタッチを検出するためのタッチ検出部５０５とを備える。【選択図】図４