• Title/Summary/Keyword: piezoelectric transducer

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Effect of Mn on Dielectric and Piezoelectric Properties of 71PMN-29PT [71Pb(Mg1/3Nb2/3)O3-29PbTiO3] Single Crystals and Polycrystalline Ceramics

  • Oh, Hyun-Taek;Joo, Hyun-Jae;Kim, Moon-Chan;Lee, Ho-Yong
    • Journal of the Korean Ceramic Society
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    • v.55 no.2
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    • pp.166-173
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    • 2018
  • In order to investigate the effect of Mn on the dielectric and piezoelectric properties of PMN-PT [$Pb(Mg_{1/3}Nb_{2/3})O_3-PbTiO_3$], four different types of 71PMN-29PT samples were prepared using the solid-state single crystal growth (SSCG) method: (1) Undoped single crystals, (2) undoped polycrystalline ceramics, (3) Mn-doped single crystals, and (4) Mn-doped polycrystalline ceramics. In the case of single crystals, the addition of 0.5 mol% Mn to PMN-PT decreased the dielectric constant ($K_3{^T}$), piezoelectric charge constant ($d_{33}$), and dielectric loss (tan ${\delta}$) by about 50%, but increased the coercive electric field ($E_C$) by 50% and the electromechanical quality factor ($Q_m$) by 500%, respectively. The addition of Mn to PMN-PT induced an internal bias electric field ($E_I$) and thus specimens changed from piezoelectrically soft-type to piezoelectrically hard-type. This Mn effect was more significant in single crystals than in ceramics. These results demonstrate that Mn-doped 71PMN-29PT single crystals, because they are piezoelectrically hard and simultaneously have high piezoelectric and electromechanical properties, have great potential for application in fields of SONAR transducers, high intensity focused ultrasound (HIFU), and ultrasonic motors.

Development and Evaluation of the Bender Type Piezoelectric Energy Harvester According to Installation Methods and Vehicle Weight (매설방법과 차량하중에 따른 벤더형 압전에너지 하베스터의 설계 및 평가)

  • Kim, Chang-Il;Jeong, Young-Hun;Yun, Ji-Sun;Cho, Jeong-Ho;Paik, Jong-Hoo;Jang, Yong-Ho;Choi, Beom-Jin;Park, Shin-Seo;Cho, Young-Bong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.29 no.5
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    • pp.274-278
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    • 2016
  • A road energy harvester was designed and fabricated to convert mechanical energy from the vehicle load to electrical energy. The road energy harvester is composed of 20 piezoelectric materials. This study attempted to evaluate output depending on pavement materials when paving road piezoelectric energy harvester in the road. Harvester is the bender type and is the method of supporting the both ends of piezoelectric material and applying the load in the middle part. Harvester was paved in the type paved with asphalt, type paved with cement and in the exposed type not covering the top of harvester. The output characteristics were compared and evaluated depending on changes in vehicle load and vehicle speed changes. As vehicles, truck (11.9 ton), SUV(1.6 ton) and sedan (1.5 ton) were used and the output characteristics when driving at the interval of 10 km/h from 10 km/h to 100 km/h were evaluated.

A Study on the Fabrication of Piezoelectric Organic Thin Films by using Physical Vapor Deposition Method and Sensor Characteristics (진공증착법을 이용한 압전 유기 박막의 제조와 센서 특성에 관한 연구)

  • Park, Su-Hong;Lim, Eung-Choon;Park, Jong-Chan;Lee, Duck-Chool
    • Proceedings of the KIEE Conference
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    • 2001.07e
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    • pp.35-39
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    • 2001
  • The purpose of this paper is improvement the piezoelectric of Polyvinylidene fluoride(PVDF) organic thin films is fabricated by vapor deposition method. The piezoelectric of PVDF organic thin films attributed to dipole orientation in crystalline region. Also, the piezoelectric characteristic reduced that dipole moments orientation in crystalline region interfered with impurity carriers. Therefore, PVDF organic thin films fabricated with high substrate temperature condition for crystallinity improvement. The crystallinity of PVDF organic thin films fabricated by this condition increase from 47 to 67.8%. The ion density of PVDF organic thin films fabricated by substrate temperature variation from $30^{\circ}C$ to $105^{\circ}C$ decreased from $1.62{\times}10^{16}cm^3$ to $6.75{\times}10^{11}cm^3$ when temperature and frequency were $100^{\circ}C$, 10Hz, respectively. The $d_{33}$ and piezo-voltage coefficient of PVDF organic thin films increased from 20pPC/N to 33pC/N and $162.9{\times}10^{-3}V{\cdot}m/N$ to $283.2{\times}10^{-3}V{\cdot}m/N$, respectively. For the sake of the applications of piezoelectric sensor, we analyzed the output voltage characteristic as a function of the distance between an oscillator of 28kHz and PVDF organic thin film transducer. From this, we found that the output voltage is inversely proportional to the distance. At this time, the period was about $35.798{\mu}s$ and equal the oscillator frequency.

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Self-Powered Integrated Sensor Module for Monitoring the Real-Time Operation of Rotating Devices (회전기기 실시간 동작상태 모니터링을 위한 자가발전 기반 센서모듈)

  • Kim, Chang Il;Yeo, Seo-Yeong;Park, Buem-Keun;Jeong, Young-Hun;Paik, Jong Hoo
    • Journal of Sensor Science and Technology
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    • v.28 no.5
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    • pp.311-317
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    • 2019
  • Rotating devices are commonly installed in power plants and factories. This study proposes a self-powered sensor node that is powered by converting the vibration energy of a rotating device into electrical energy. The self-powered sensor consists of a piezoelectric harvester for self-power generation, a rectifier circuit to rectify the AC signal, a sensor unit for measuring the vibration frequency, and a circuit to control the light emitting diode (LED) lighting. The frequency of the vibration source was measured using a piezoelectric-cantilever-type vibration frequency sensor. A green LED was illuminated when the measured frequency was within the normal range. The power generated by the piezoelectric harvester was determined, and the LED operation was assessed in terms of the vibration frequency. The piezoelectric harvester was found to generate a power of 3.061 mW or greater at a vibration acceleration of 1.2 g ($1g=9.8m/s^2$) and vibration frequencies between 117 and 123 Hz. Notably, the power generated was 4.099 mW at 122 Hz. As such, our self-powered sensor node can be used as a module for monitoring rotating devices, because it can convert vibration energy into electrical energy when installed on rotating devices such as air compressors.

Ultrasonic Transducer Application for Nondestructive Testing of Continuous Cast Billets (연주빌렛의 비파괴 검사를 위한 초음파 센서의 응용)

  • Shin, Byoung-Chul;Kwon, Jeong-Rock
    • Journal of Sensor Science and Technology
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    • v.5 no.3
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    • pp.25-31
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    • 1996
  • Steel wires are made by elongating hot billets. If the billets have internal or surface defects, the wire can be broken during elongation process. After testing surface defect, we are testing internal defect by ultrasonic transducers. POSCO is producing two kinds of billets, hot rolled billet and cast billet. Hot rolled one is denser than cast billet. Because of the low density and rough surface, ultrasonic testing is difficult for the cast billet. Size of the transducer was related with the size and density of the billet. A transducer having 21mm long, 8.5mm wide and 0.95mm thick piezoelectric ceramic plate was best for $160mm\;{\times}\;160mm$ cast billet. Center frequency of the transducer was 2.25MHz and the focus distance was 70mm.

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Study on the Design Method of the Energy Harvesting Smart Sensor for Implementing IoT Service (IoT 서비스 구현을 위한 에너지 하베스팅 Smart Sensor 설계 방안 연구)

  • Jang, Ho-Deok
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.11 no.1
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    • pp.89-94
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    • 2018
  • This paper investigated the design method of the smart sensor for implementing IoT (Internet of Things) service. The power supply of sensor consistently acquisting data is based on the energy harvesting technology and designed with piezoelectric transducer not affected by surrounding circumstances. The wireless communication interface for the transmission of data is designed with BLE (Bluetooth Low Energy). BLE is highly adequate wireless communication technology for low power consumption and short distance wireless communication. The main application of BLE is beacon whose usage range is extended from O2O (Online to Offline) service, navigator based on indoor positioning technology, and anti-theft/lost child prevention service to mobile game. This paper studied the method to extend wireless coverage for complementing the short wireless transmission distance of BLE. The wireless sensor network based on CATV network is proposed for the easy construction of BLE sensor network and extended wireless coverage.

Magnetostriction Measurement of an $Fe_49Co_49V_2$ Alloy using the Michelson Laser Interferometer Compensated by Feedback Signal (궤환신호로 보상되는 Michelson 레이저 간섭계를 이용한 $Fe_49Co_49V_2$ 합금의 자기변형 측정)

  • 안승준;김철기;김호섭;김호철;남궁정
    • Journal of the Korean Magnetics Society
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    • v.10 no.5
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    • pp.246-249
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    • 2000
  • An Fe$_{49}$ Co$_{49}$ V$_2$alloy is annealed in thermal annealing furnace at 50$0^{\circ}C$, 75$0^{\circ}C$, 80$0^{\circ}C$, and 90$0^{\circ}C$. Annealed samples were cooled in air. The magnetostriction is measured by using a Michelson laser interferometer. Receiving the feedback signal of interference, a mirror attached to piezoelectric transducer (PZT) maintains the optical path length (OPL) between two arms of laser interferometer relatively constant. The feedback voltage is calibrated to the OPL variation. A magnetostriction of 2$\times$10$^{-6}$ at H = 60 Oe increases up to 33.68$\times$10$^{-6}$ at an annealing temperature of 90$0^{\circ}C$, suggesting that the magnetostrictive characteristics are improved by the microstructural modification.

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Non-contact Transportation of Flat Panel Substrate by Combined Ultrasonic Acoustic Viscous and Aerostatic Forces

  • Isobe, Hiromi;Fushimi, Masaaki;Ootsuka, Masami;Kyusojin, Akira
    • International Journal of Precision Engineering and Manufacturing
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    • v.8 no.2
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    • pp.44-48
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    • 2007
  • In recent years, the size of plane substrates and semiconductor wafers has increased. As conventional contact transportation systems composed of, for example, carrier rollers, belt conveyers, and robot hands carry these longer and wider substrates, the increased weight results in increased potential for fracture. A noncontact transportation system is required to solve this problem. We propose a new noncontact transportation system combining acoustic viscous and aerostatic forces to provide damage-free transport. In this system, substrates are supported by aerostatic force and transported by acoustic viscous streaming induced by traveling wave deformation of a disk-type stator. A ring-type piezoelectric transducer bonded on the stator excites vibration. A stator with a high Q piezoelectric transducer can generate traveling vibrations with amplitude of $3.2{\mu}m$. Prior to constructing a carrying road for substrates, we clarified the basic properties of this technique and stator vibration characteristics experimentally. We constructed the experimental equipment using a rotational disk with a 95-mm diameter. Electric power was 70 W at an input voltage of 200 Vpp. A rotational torque of $8.5\times10^{-5}Nm$ was obtained when clearance between the stator and disk was $120{\mu}m$. Finally, we constructed a noncontact transport apparatus for polycrystalline silicon wafers $(150(W)\times150(L)\times0.3(t))$, producing a carrying speed of 59.2 mm/s at a clearance of 0.3 mm between the stator and wafer. The carrying force when four stators acted on the wafer was $2\times10^{-3}N$. Thus, the new noncontact transportation system was demonstrated to be effective.

Development and Evaluation of Rack Type Piezoelectric Harvester for Smart Street Lamps Control (가로등 제어용 다층패드형 압전 하베스터의 개발 및 평가)

  • Kim, Chang-Il;Jeong, Young-Hun;Park, Woon Ik;Cho, Jeong-Ho;Jang, Yong-Ho;Choi, Beom-Jin;Park, Shin-Seo;Paik, Jong-Hoo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.29 no.11
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    • pp.696-701
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    • 2016
  • In this study, to increase output of road piezoelectric energy harvester, it was made into rack type in which many piezoelectric materials can be installed and load transfer device of the leverage type to transfer vehicle load was made. By paving it in the road, the output characteristics depending on vehicle load and speed were evaluated. Changing vehicle load, harvester output characteristics depending on speed changes were evaluated at the interval of 10 km/h from 10 km/h to 100 km/h. Also, by making a wireless switch and sending wireless signal with output of rack type harvester, whether to receive it was evaluated by distance. It was checked that all switches work up to front-to-back 100 m from harvester.