| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce an influence even if noise is contaminated in an output signal of an electrostatic sensor.SOLUTION: An electrostatic sensor 310 is configured from first and second sensors 310(u), 310(l) both of which detect a charge quantity by electrostatic induction. The first and second sensors 310(u), 310(l) are so disposed as to be vertically adjacent to and separated from each other. Outputs of said vertical electrostatic sensors 310(u), 310, (l), which are temporarily off-set, are differentiated by an operational amplifier 332, and are therefore made to be an amplified waveform.</p> |
