• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.215-216
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• 2008

Using the extensional vibration mode of PZT ring, a piezopump is successfully made. The PZT ring is polarized with thickness direction. The traveling extensional wave along the circumference of the ring is obtained by dividing two standing waves which are temporally and spatially phase shifted by 90 degrees from each other. The proposed piezopump is consisted of coaxial cylindrical shells that are bonded piezoelectric ceramic ring.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1301_1302
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• 2009

Recently, there has been increased incessantly an interest in research area on micro-fluidic pump for electronic and biological applications. The proposed pump takes an unobtrusive operation into the simple displacing mechanism using peristaltic traveling waves without the physical moving valves. And, this piezopump makes up a panel type design. The ATILA simulation was performed to estimate the operating frequency of the vibrating wave mode, to optimize the design conditions of piezopump such as structure, elastic body material, piezoelectric ceramics, and to analyze the distribution of vibration displacement. The best measured value of the pumping rate is about $118{\mu}l$/min under the following parameters : 4-wave mode, 50kHz operating frequency, $200V_p$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 Techno-Fair 및 추계학술대회 논문집 전기물성,응용부문
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• pp.119-120
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• 2008

Using the extensional vibration mode of PZT bar, a piezopump is successfully made. The traveling extensional wave along the circumference of the bar is obtained by dividing standing waves which are temporally and spatially phase shifted by 90 degrees from each other. The proposed piezopump is consisted of coaxial cylindrical shells that are bonded piezoelectric ceramic bar.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1824-1827
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• 2005

For application to micro fluid control systems such as ${\mu}TAS$ (Micro Total Analysis Systems) and DDS (Drug Delivery Systems), it is very significant to handle precise and minute flow rates with low pressure pulsation. In this study, a novel valveless piezoelectric pump using peristaltic motion with three disk type PZT actuators is presented. The newly devised pump with an effective size of $70mm{\times}60mm{\times}55mm$ has three actuator layers connected in series from inlet to outlet. The PZT actuator has a maximum displacement of 240 ${\mu}m$ and a maximum force of 1.6 N. When the driving voltage for PZT actuators is sequentially applied with a certain phase shift, the pumping is performed by peristaltic motion of liquid volume. The working fluid is shut off without the driving voltage. Three methods for sequential driving are proposed and experimentally investigated. First and second methods utilize an intermittent sinusoidal waveform with phase shift of $90{\circ}\;and\;120^{\circ}$, respectively. Third method uses a rectangular waveform with phase shift of $90^{\circ}$. A controller with multi-phase shifter is designed and fabricated. Then, frequency and voltage-flow rate characteristics and load pressure-flow rate characteristics are experimentally investigated to verify the validity of the developed pump.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1275_1276
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• 2009

Micropump is very useful component in micro/nano fluidics and bioMEMS applications. Using the flexural vibration mode of PZT bar, a piezopump is successfully made. The PZT bar is polarized with thickness direction. The proposed structure for the piezo-pump consists of an input and an output port, piezoelectric ceramic actuator, actuator support, diaphragm. The traveling flexural wave along the bar is obtained by dividing two standing waves which are temporally and spatially phase shifted by 90 degrees from each other. Fluid is drawn into a forming chamber, eventually the forming chamber closes trapping the fluid therein.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2002년도 마이크로/바이오 가시화기술부문 학술강연회
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• pp.1-7
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• 2002

This papers describes the preparation and experimental results of a micro mass detection devices based on cantilever and a diffuser-type micro pump using screen printing thick-film technologies and Si micro-machining. PZT-PCW thick films were prepared by new hybrid method based on the screen printing. By applying these PZT-PCW piezoelectric thick films on actuator, a cantilever for mass detection sensor and a micropump for microfluidic element are successfully fabricated. Resonant frequency and displacement of PZT-PCW thick film actuator in air and in liquid are measured by laser vibrometer system as a function of actuator size. The resonant frequency of PZT-PCW thick film actuator in liquid decreases order of 1/2-1/4 due to damping effect. The sensitivity of cantilever is characterized by Au deposition method which has the mass loading effect such as adsorption of protein. The Sensitivity of PZT-0.12PCW thick film cantilever is proportional to detecting area.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.615-618
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• 2005

All over the world, many kinds of micro-actuators were already developed for various applications. The actuators are using various principles such as electromagnetic, piezoelectric and thermopneumatic etc. The most of the micro-actuators have been made using 2D based MEMS technology. In these actuators, it is difficult to drive 3-dimensional motion. This characteristic gives the limit of actuator application. However, micro-stereolithography technology has made it possible to fabricate freeform three-dimensional microstructures. In this technology, 2-dimensional micro-shape layer is cumulated on the other layers. This layer-by-layer process is the main principle to fabricate 3-dimensioal micro-structures. In this research, a micro-bellows actuator that is vertically moving was developed using the micro-stereolithography technology. When pressure was applied into the bellows, a non-contact actuating motion is generated. For actuation experiment, syringe pump and laser interferometer were used for applying pressure and measuring the displacement. Several hundreds micro-scale actuation was observed. And, to demonstrate the feasibility of proposed actuation principle, in this research, a micro-gripper was developed using half-bellows structure.

• 한국정밀공학회지
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• 제27권10호
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• pp.84-92
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• 2010

In this study a numerical analysis has been conducted for the flow characteristics and pumping performance of a piezoelectric-based micropump with electromagnetic resistance exerted on electrically conducting fluid. Here, electromagnetic resistance is alternately applied at the inlet and outlet with alternately applied magnetic fields in association with the reciprocal membrane motion of the piezoelectric-based micropump. A model of Prescribed Deformation is used for the description of the membrane motion. The internal flow characteristics and pumping performance are investigated with the variation of magnetic flux density, tube size, displacement of membrane and the frequency of the membrane. It turns out that the current micropump has a wide range of pumping flow rate compared with diffuser-nozzle based micropumps.

• 한국항공우주학회지
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• 제36권1호
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• pp.7-13
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• 2008

본 논문에서는 유한요소법을 기반으로 한 소프트웨어 COMSOL Multiphysics를 이용하여 압전 복합재료 작동기를 이용하여 제작한 무밸브 마이크로펌프의 성능을 연구하였다. 압전 마이크로펌프는 4층의 경량 압전 복합재료 작동기, PDMS으로 된 챔버와 2개의 디퓨저로 이루어졌다. 시뮬레이션에서는 압전 재료 영역, 구조 영역과 유체 영역을 완전 연성하여 해를 계산하였다. 물을 유체로 사용하였으며, 유량을 마이크로펌프의 구조적 파라미터에 대하여 계산하였다. 이 연구에 기초하여 보다 성능이 좋은 마이크로펌프를 제시하였다.

• Journal of Power Electronics
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• 제16권3호
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• pp.1226-1235
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• 2016

For wearable health monitoring systems, a fundamental problem is the limited space for storing energy, which can be translated into a short operational life. In this paper, a highly efficient active voltage doubling rectifier with a wide input range for micro-piezoelectric energy harvesting systems is proposed. To obtain a higher output voltage, the Dickson charge pump topology is chosen in this design. By replacing the passive diodes with unbalanced-biased comparator-controlled active counterparts, the proposed rectifier minimizes the voltage losses along the conduction path and solves the reverse leakage problem caused by conventional comparator-controlled active diodes. To improve the rectifier input voltage sensitivity and decrease the minimum operational input voltage, two low power common-gate comparators are introduced in the proposed design. To keep the comparator from oscillating, a positive feedback loop formed by the capacitor C is added to it. Based on the SMIC 0.18-μm standard CMOS process, the proposed rectifier is simulated and implemented. The area of the whole chip is 0.91×0.97 mm², while the rectifier core occupies only 13% of this area. The measured results show that the proposed rectifier can operate properly with input amplitudes ranging from 0.2 to 1.0V and with frequencies ranging from 20 to 3000 Hz. The proposed rectifier can achieve a 92.5% power conversion efficiency (PCE) with input amplitudes equal to 0.6 V at 200 Hz. The voltage conversion efficiency (VCE) is around 93% for input amplitudes greater than 0.3 V and load resistances larger than 20kΩ.