• 제목/요약/키워드: piezoelectric Micro-machined Ultrasonic Transducer (pMUT)

검색결과 3건 처리시간 0.015초

공기 중 광대역 초음파 방사용 압전 박막 기반 초소형 초음파 트랜스듀서의 설계 (Design of piezoelectric micro-machined ultrasonic transducer for wideband ultasonic radiation in air)

  • 안홍민;진재혁;문원규
    • 한국음향학회지
    • /
    • 제39권2호
    • /
    • pp.87-97
    • /
    • 2020
  • 본 논문에서는 공기 중 광대역 초음파 방사용 압전 박막 기반 초소형 초음파 트랜스듀서(piezoelectric Micro-machined Ultrasonic Transducer, pMUT)의 설계 연구가 진행되었다. 하나의 트랜스듀서로 광대역을 달성하는 방법 중 하나는 다공진 시스템으로 설계하는 것이다. 새로운 pMUT은 박막 구조의 앞면과 뒷면에 적절한 음향 구조를 추가하여 다공진 시스템을 구현하도록 설계되었다. 박막 앞쪽은 도파관 구조로 모델링된 방사 파트로, 박막 뒷쪽은 음향 공동으로 모델링된 패키징 파트로 이루어져있다. 박막 파트, 방사 파트, 패키징 파트로 구성된 새로운 pMUT은 집중 변수 모델로 설계되었으며, 최종적으로 유한요소해석으로 검증되었다. 최종 설계된 pMUT은 102 kHz ~ 132 kHz (-3 dB)의 주파수 대역을 달성하였다.

음향 매질의 추가질량 효과를 고려한 광음향 영상용 초소형 압전 기반 초음파 트랜스듀서의 개발 (Development of a Piezoelectric Micro-machined Ultrasonic Transducer for Photoacoustic Imaging that Accounts for the Added Mass Effect of the Acoustic Medium)

  • 안홍민;문원규
    • 센서학회지
    • /
    • 제29권1호
    • /
    • pp.33-39
    • /
    • 2020
  • Typically, photoacoustic images are obtained in water or gelatin because the impedance of these mediums is similar to that of the human body. However, these acoustic mediums can have an additional mass effect that changes the resonance frequency of the transducer. The acoustic radiation impedance in air is negligible because it is very small compared to that of the transducer. However, the high acoustic impedance of mediums such as the human body and water is quite large compared to that of air, making it difficult to ignore. Specifically, in a case where the equivalent mass is very small, such as with a micro-machined ultrasound transducer, the additional mass effects of the acoustic medium should be considered for an accurate resonance frequency design. In this study, a piezoelectric micro-machined ultrasonic transducer (pMUT) was designed to have a resonance frequency of 10 MHz in the acoustic medium of water, which has similar impedance as the human body. At that time, the resonance frequency of the pMUT in air was calculated at 15.2 MHz. When measuring the center displacement of the manufactured pMUT using a laser vibrometer, the resonance frequencies were measured as 14.3-15.1 MHz, which is consistent with the finite element method (FEM) simulation results. Finally, photoacoustic images of human hair samples were successfully obtained using the fabricated pMUT.

고지향성 압전 트랜스듀서용 새로운 고효율 전력 증폭기 (New High-efficiency Power Amplifier System for High-directional Piezoelectric Transducer)

  • 김진영;김인동;문원규
    • 전기학회논문지
    • /
    • 제67권3호
    • /
    • pp.383-390
    • /
    • 2018
  • Piezoelectric micro-machined ultrasonic transducers for highly directional speaker need DC bias voltage. Most existing power amplifiers are not suitable for use in highly directional transducers because they are based on AC. In addition, since the piezoelectric micro-machined ultrasonic transducer has a large capacitive reactance, the power efficiency of the power amplifier is very low. Thus this paper proposes a new high efficiency power amplifier with DC bias voltage. In addition, by designing a matching circuit to compensate the capacitive reactance of the micro-machined ultrasonic transducer, the power efficiency of the power amplifier increases. The operating characteristics of the proposed power amplifier was verified by an experimental prototype. The proposed power amplifier is expected to be widely used in designing and implementing other related power amplifiers.