| 摘要 |
PROBLEM TO BE SOLVED: To obviate an electrode dedicated to vibration detection. SOLUTION: Two diaphragms 261, 262 are mounted in a low-pass filter 212 and when vibrating the low-pass filter 212 for shaking down a foreign substance deposited on a front-side surface of the low-pass filter 212, the two diaphragms 261, 262 are simultaneously driven. Furthermore, when detecting a vibrating state of the low-pass filter 212, any one of the diaphragm 261, 262 is driven to be vibrated and based on a voltage generated at the other diaphragm, the vibrating state of the low-pass filter 212 is detected. Thus, an electrode dedicated to vibration detection is obviated and costs can be reduced. COPYRIGHT: (C)2009,JPO&INPIT |
