• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권6호
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• pp.456-461
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• 1999

In this study, the characteristics of Ultrasonic Transducer fabricated with PZT-Polymer 1-3 type piezoelectric ceramic/polymer composite are investigated. 3-D underwater object restoration using the self-made ultrasonic transducer and modified SCL(Simple Competitive Learning) neural network was presented. The ultrasonic transducer was satisfied with the required condition of commerical ultrasonic transducer in underwater. The modified SCL neural network using the acquired object data $16\times16$ low resolution image was used for object restoration of $32\times32$ high resolution image. The experimental results have shown that the ultrasonic transducer fabricated with PZT-Polymer 1-3 type piezoelectric ceramic/polymer composite could be applied for SONAR system.

• 한국수산과학회지
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• 제47권3호
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• pp.302-312
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• 2014

This article describes the design and performance characteristics of a broadband ultrasonic mosaic transducer. We focus on the improved bandwidth in the high frequency band of a previously designed broadband ultrasonic transducer (Lee et al., 2014). The improvement in the pulse-echo bandwidth was achieved by employing twelve $2{\times}2$ element subarrays, operating at different resonance frequencies, and utilizing the mosaic array concept. We found that the -6 dB and -12 dB bandwidths of the newly developed broadband ultrasonic mosaic transducer, were up to 155% and 170% of the previously designed model, with a quality factor of 1.71 and 1.25, respectively. The averaged TVR (transmitting voltage response), SRT (receiving sensitivity), and FOM (figure of merit) values in a nearly flat transmitting response band, from 45 to 105 kHz providing a -12 dB bandwith of 60 kHz, were 163.3 dB (re $1{\mu}Pa/V$ at 1 m), -192.8 dB (re $1V/{\mu}Pa$), and -30.9 dB, respectively.

• 한국전기전자재료학회논문지
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• 제21권2호
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• pp.131-136
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• 2008

The transducer for multi-directionally movable ultrasonic motor having lambda shaped vibrators has been proposed and designed. The two branches cross at a right angle with each other at the tip. FEM analyses of lambda shaped transducer were carried out to find vibration modes for ultrasonic motor. The lambda shaped transducer has one symmetric mode and two anti-symmetric modes. The symmetric mode generates the normal direction motion of the tip. The lateral and vertical direction motion of the tip are excited by two anti-symmetric modes. The normal and lateral direction motions made an lateral elliptic trajectory. And the normal and vertical direction motions made an vertical elliptic trajectory normal to previous one. The transducer with 1 mm in thickness and 25 mm in length has been fabricated and evaluated. The resonance frequencies of the transducer was 32 kHz and 103 kHz. The tangential and vertical vibration displacement of the transducer having the lateral elliptic trajectory were $1.5{\mu}m\;and\;1.1{\mu}m$, respectively at the driving voltage of 100 Vpp and frequency of 32 kHz and 103 kHz. And the tangential and vertical vibration displacement of the transducer having the vertical elliptic trajectory were $0.4{\mu}m\;and\;0.2{\mu}m$, respectively at the same driving condition.

• Smart Structures and Systems
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• 제1권1호
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• pp.47-61
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• 2005

A ring-shaped lead zirconate titanate (PZT) piezoceramic sensor has been integrated with the Langevin-type piezoceramic driver of an ultrasonic wire-bonding transducer to form a smart transducer for in-situ measurement of three essential bonding parameters: namely, impact force, ultrasonic amplitude and bond time. This sensor has an inner diameter, an outer diameter and a thickness of 12.7 mm, 5.1 mm and 0.6 mm, respectively. It has a specifically designed electrode pattern on the two major surfaces perpendicular to its thickness along which polarization is induced. The process-test results have indicated that the sensor not only is sensitive to excessive impact forces exerted on the devices to be bonded but also can track changes in the ultrasonic amplitude proficiently during bonding. Good correlation between the sensor outputs and the bond quality has been established. This smart transducer has good potential to be used in automatic process-control systems for ultrasonic wire bonding.

• 전자공학회논문지A
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• 제30A권2호
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• pp.22-28
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• 1993

In this paper, the ultrasonic transducer with a spherical liquid lens is designed and an efficient method to calculate the acoustic field radiated from the transducer is presented. A prototype ultrasonic transducer with a spherical liquid lens is constructed and tested. The experimental results are compared with those of the computer simulations and good agreements are achieved. The dynamic control of the geometric focus is obtained by adjusting the radius of curvature of the lens membrane with the volumetric control of the liquid in the lens.

• 센서학회지
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• 제18권1호
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• pp.33-41
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• 2009

A multilevel acoustic Fresnel lens (MAFL) for the ultrasonic imaging transducer of which center frequency is approximately 5.MHz was newly designed and fabricated. The phase level of the lens was 64, and the focal length and the aperture width were 30.mm and 11.mm, respectively. The characteristics of impulse response, acoustic field and imaging performance of the transducer attached the lens were compared with the transducer attached a conventional refraction type acoustic lens (RAL). The results show that the center frequency, the loop sensitivity, and the focal depth of the MAFL transducer were higher or larger than those of the RAL transducer by approximately 0.2.MHz, 1.4.dB, and 2.mm, respectively. Consequently, it was shown that the brighter acoustic images with higher lateral resolution and the increased imaging performance for deep targets can be obtained by using the MAFL transducer.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전기물성,응용부문
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• pp.137-139
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• 2003

Transducer for ultrasonic linear motor with the symmetric and anti-symmetric modes was studied. The ultrasonic linear motor consists of two Langevin type piezoelectric vibrators that cross at right angles with each other in tip. In order to excite symmetric and anti-symmetric modes, the transducer must have a phase shift of 90 degree in space and time. Therefore, the tip of transducer moves on an elliptical motion. In this paper, the finite element analysis was used to optimize dimension and displacement of the transducer The ultrasonic motor was fabricated using the simulated result and the driving characteristics were measured. No-load velocity was 0.28[m/s] and the maximum efficiency was 30[%] in resonance frequency.

• 한국음향학회지
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• 제35권6호
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• pp.466-472
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• 2016

본 연구에서는 고분해능 초음파 영상 획득이 가능한 20 MHz 대역의 의료용 초음파 선형 배열 트랜스듀서를 개발하였다. 먼저 고주파 음파의 전파가 용이한 트랜스듀서의 구조를 고안한 후, 구성소자의 최적치수를 도출하였다. 이후 설계에 따라 트랜스듀서의 제작공정을 개발하고, 트랜스듀서 시편의 제작 및 평가를 수행하였다. 제작된 초음파 트랜스듀서는 중심주파수가 19 MHz이고, 비대역폭이 84.5 %, 감도의 표준편차가 0.74 dB로 측정되었다. 측정 결과는 설계 결과와 잘 일치하였으며, 이에 의해 본 연구에서 개발한 고주파 초음파 트랜스듀서 구조의 타당성을 검증하였다. 개발된 트랜스듀서는 새로운 구조에 의해 기존의 20 MHz 트랜스듀서에 비해 더 넓은 주파수 대역폭과 균일한 감도를 가지는 것으로 확인되었다.

• 한국음향학회지
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• 제39권2호
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• pp.87-97
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• 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.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.856-859
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• 2005

The OPMT(Orientation-adjustable Patch-type Magnetostrictive Transducer) was proposed as a tool for generating and measuring the ultrasonic Lamb wave in plate type structures. This sensor has a lot of new features compared to the traditional piezo-type ultrasonic transducers. As an example, it does not need any kind of wiring for lunching or measuring ultrasonic waves. But it has also definite limitation for practical usage as a nondestructive testing tool in that it cannot help rotating the direction of ultrasonic wave manually. The idea for 'scanning OPMT' is proposed in this respect. Two kinds of basic ideas for rotating the wave direction not manually but electrically are proposed. The fabrication of the transducer and the testing for Identifying the primary characteristics are done for one of the proposed transducers. The results says that there are the possibilities as a new tool for NDE in that the proposed transducer follows well the characteristics of the traditional OPMT. But there are also the 1imitations to overcome.