Patent ID: 9094016
Filing Date: 2015-07-28
Classification: H03K

Abstract:
1. A touch sensor comprising an oscillator which outputs a periodical operation signal; an antenna electrode which has an electrostatic capacitance and varies a waveform of the operation signal due to an approximation of a human body to form an output voltage; an output voltage line which is connected between the oscillator and the antenna electrode to transmit the operation signal from the oscillator to the antenna electrode and transmits the output voltage from the antenna electrode; a source signal line which is connected to a source voltage and transmits a predetermined reference voltage; a detection circuit which (i) compares the output voltage inputted from the output voltage line with the reference voltage inputted from the source signal line and (ii) when the output voltage is greater than the reference voltage, outputs a predetermined voltage, and integrates the predetermined voltage for a predetermined time and outputs the integrated voltage as a detection value; a determination means which determines that a human body is proximate to the antenna electrode when the detection value is continuously smaller than a proximate threshold value for longer than a predetermined determination duration; and an adjustment means which changes a frequency of the operation signal so that the detection value gets closer to a predetermined standard value when the detection value is continuously smaller than a change threshold for longer than a predetermined change duration, wherein the change duration is longer than the determination duration.