A human body detection method using a capacitive proximity sensor, wherein the capacitive proximity sensor comprises:
- an oscillation means, which outputs a high-frequency signal;
- a sensor circuit to which a high-frequency signal is input, and which includes a sensor electrode;
- a detection circuit, which outputs a determination voltage signal corresponding to the capacitance of the sensor electrode, based on an electrical signal output from the sensor circuit;
- and
- a control unit,
- wherein the sensor circuit has an LCR series resonance circuit, in which a coil L, a capacitor C, and a resistor R are connected in series in this order;
- the sensor electrode is connected downstream of the coil L and upstream of the capacitor C;
- the detection circuit outputs the determination voltage signal based on the electrical signal at a detection point downstream of the capacitor C and upstream of the resistor R;
- and
- the control unit detects the proximity of a human body to the sensor electrode, based on the determination voltage signal;
- and
- with fA being the resonance frequency of the sensor circuit when no object is in the proximity of the sensor electrode, and fB being the resonance frequency of the sensor circuit when a human body is in the proximity of the sensor electrode, where the relationship is
- fB<fA
- a first detection frequency f1 and a second detection frequency f2, which satisfy the relationship
- fB≤f1<f2<fA
- are set;
- with V1 being the determination voltage signal upon having input the high-frequency signal at the first detection frequency f1 to the sensor circuit, when no object is in the proximity of the sensor electrode, a first threshold value Vth1 which satisfies the relationship
- V1<Vth1
- is set;
- with V2 being the determination voltage signal upon having input the high-frequency signal at the second detection frequency f2 to the sensor circuit, when no object is in the proximity of the sensor electrode, a second threshold value Vth2 which satisfies the relationship
- V2<Vth2
- is set;
- and
- the proximity of a human body to the sensor electrode is detected by detecting that, upon having input the high-frequency signal at the first detection frequency f1 to the sensor circuit, the determination voltage signal has reached or exceeded the first threshold value Vth1, or that, upon having input the high-frequency signal at the second detection frequency f2 to the sensor circuit, the determination voltage signal has reached or exceeded the second threshold value Vth2.