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2014 Vol.33, Issue 2 Preview Page
Effect of a Bonding Layer between Electrodes on the Performance of a -Mode PVDF Ultrasound Transducer

모드 PVDF 초음파 트랜스듀서에 있어서 전극 사이의 접합층이 성능에 미치는 영향

Yonggang Cao1
,
Kanglyeol Ha1*
,
Moojoon Kim1
,
Jungsoon Kim2
Cao Yonggang1
,
하 강렬1*
,
김 무준1
,
김 정순2
1부경대학교 물리학과
2동명대학교 멀티미디어공학과
*교신저자. *Corresponding Author. 
31 March 2014. pp. 102-110
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Abstract

The effect of a bonding layer on the performance of a quarter-wave (λ/4) mode PVDF ultrasound transducer having not only a piezoelectric layer but also a non-piezoelectric layer between two electrodes was analyzed. The equivalent circuit of a transmission line model by Kikuchi et al.[Sound of IEICE, 55-A, 331-338 (1981)] was introduced for the analysis. The validity of the model was confirmed by comparison with a KLM model for three postulated adhesion cases of a 80 µm thick piezoelectric PVDF film to a copper (Cu) backer. The pulse-echo responses of five PVDF transducers, each fabricated with a different thickness (5 µm ~ 20 µm) of the bonding layer, were measured and the results were compared with those by simulation. The two results were in good agreement with each other and it was noted that the effect of the bonding layer on the performance of the transducer could be analyzed by the Kikuchi model. In detail, the 20 µm bonding layer decreased the center frequency and the bandwidth by about 19.7 % and 25.0 %, respectively, and increased the insertion loss by 57.2 %.

Keywords
Ultrasonic transducer
Equivalent circuit
PVDF piezoelectric film
Bonding layer
Pulse-echo response

양 전극 사이에 압전층 외에 비압전성의 접합층이 존재하는 모드 PVDF 초음파 트랜스듀서에 있어서 그 접합층이 트랜스듀서의 성능에 미치는 영향을 등가회로에 의해 해석하였다. 등가회로로서는 Kikuchi 등이 제안한 전송선로 모델[Sound of IEICE, 55-A, 331-338 (1981)]을 도입하였는데, 먼저 그 모델에 의한 해석의 타당성을 80 µm 두께의 PVDF 압전막이 동(Cu) 후면체에 부착되는 세 가지 경우를 가정한 KLM 모델과의 비교를 통해 검증하였다. 다음으로, 그 압전막과 더불어 5 µm ~ 20 µm 두께의 에폭시 접합층을 갖는 다섯 개의 트랜스듀서를 제작하여 펄스에코 응답을 측정한 후 시뮬레이션 결과와 비교하였다. 두 결과는 서로 잘 일치하였는바, 도입한 Kikuchi 모델에 의해 접합층이 트랜스듀서의 성능에 미치는 영향을 파악할 수 있음을 알았는데, 접합층이 20 µm 일 때는 그 접합층이 없을 때에 비해 중심주파수와 대역폭은 각각 약 19.7 %, 25.0 % 감소하고, 삽입손실은 57.2 % 증가하는 것으로 나타났다.

키워드
초음파 트랜스듀서
등가회로
PVDF 압전막
접합층
펄스에코 응답
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Information
  • Publisher :The Acoustical Society of Korea
  • Publisher(Ko) :한국음향학회
  • Journal Title :The Journal of the Acoustical Society of Korea
  • Journal Title(Ko) :한국음향학회지
  • Volume : 33
  • No :2
  • Pages :102-110
  • Received Date : 2013-09-27
  • Revised Date : 2013-12-10
  • Accepted Date : 2014-01-04
  • DOI :https://doi.org/10.7776/ASK.2014.33.2.102
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