PROBLEM TO BE SOLVED: To prevent deterioration of the conversion efficiency of ultrasonic vibration to bulk wave or surface acoustic wave when the bulk wave or surface acoustic wave is generated on an observation window to which dirt is adhered to clean the observation window surface together with water feeding.SOLUTION: The endoscopic system 1 performs a water feeding step in which a control means 5 drives a washing water supply means in a washing step to feed washing water to the surface of the observation window 32 a diffraction grating cleaning step of driving an ultrasonic oscillator 37 only for a first time t1 at a first power W1 to clean a diffraction grating 40 and an observation window cleaning step of driving the ultrasonic oscillator 37 only for a second time t2 at a second power W2, after the diffraction grating cleaning step, to clean the observation window.COPYRIGHT: (C)2012,JPO&INPIT【課題】 汚れが付着した観察窓にバルク波、または表面弾性波を発生させ、送水と共に観察窓表面の洗浄を行なう際、超音波振動のバルク波、または表面弾性波への変換効率低下の防止。【解決手段】 内視鏡システム1は、洗浄工程のときに、制御手段5が洗浄水供給手段を駆動して、観察窓32の表面に洗浄水を供給する送水工程と、超音波振動子37を第1の電力W1で第1の時間t1だけ駆動して、回折格子40を洗浄する回折格子洗浄工程と、回折格子洗浄工程の後に超音波振動子37を第2の電力W2で第2の時間t2だけ駆動して観察窓を洗浄する観察窓洗浄工程と、を実行する。【選択図】図11
