| 摘要 |
<p>PROBLEM TO BE SOLVED: To detect the approach and contact of a human body speedily and securely by outputting a detection signal of logical sum of an electrostatic capacity sensor which detects the approach and contact of the human body based on changes of electrostatic capacity and a pressure sensitive sensor which detects the presence of external pressure. SOLUTION: When a human body approaches a sensor part 42, capacity of a variable capacitor 42 in a resonance circuit 23 is increased first, resonance frequency of the circuit 23 is reduced so that it approaches oscillation frequency of an oscillation circuit 22, and an output of the circuit 23 is increased. Consequently, an output of an OP amplifier 47 is changed over to turn on a switching transistor 52 and output a low level signal from an output terminal 55. Furthermore, when a pressure sensitive element 11 is depressed by the human body, resistance value of pressurized conducting rubber 15 is reduced, a voltage between terminals in a parallel circuit with a relay 12 is reduced, a current which flows in the relay 12 is reduced, and a relay contact 12a is turned on. A detection signal of logical sum of a pressure sensitive sensor 1 and an electrostatic capacity sensor 2 is outputted from an output means 3.</p> |
