초음파 Spectroscopy에 의한 두께측정을 위한 다중반사파의 시뮬레이션

Computer Simulation of Multiple Reflection Waves for Thickness Measurement by Ultrasonic Spectroscopy

  • 박익근 (천안공업전문대학 용접기술과) ;
  • 한응교 (한양대학교 정밀기계공학과) ;
  • 최만용 (한국표준과학연구원)
  • 발행 : 1992.03.30

초록

Ultrasonic spectroscopy is likely to become a very powerful NDE method for detection of microfects and thickness measurement of thin film below the limit of ultrasonic distance resolution in the opaque materials, provides a useful information that cannot be obtained by a conventional ultrasonic measuring system. In this paper, we considered a thin film below the limit of ultrasonic distance resolution sandwitched between two substances as acoustical analysis model, demonstrated the usefulness of ultrasonic spectroscopic analysis technique using information of ultrasonic frequency for measurements of thin film thickness, regardless of interference phenomenon and phase reversion of ultrasonic waveform. By using frequency intervals(${\triangle}f$) of periodic minima from the ratio of reference power spectrum of reflective waveform obtained a sample to power spectrum of multiple reflective waves obtained interference phenomenon caused by ultrasonic waves reflected at the upper and lower surfaces of a thin layer, can measured even dimensions of interest are smaller than the ultrasonic wave length with simplicity and accuracy.

키워드