• 대한기계학회논문집B
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• 제31권12호
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• pp.1017-1023
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• 2007

This study is intended to analyze the effect of thin ink-film thickness around rotating printing roll on the printing quality in the gravure printing process which is used for making electronics circuit like a RFID tag with a conductive ink. The present work numerically estimates the film thickness around rotating roller partially immersed in ink for which the volume of fluid (VOF) method was adopted to figure out the film formation process around rotating roller. Parameter studies were performed to compare the effect of ink properties (viscosity, surface tension), operating condition (roller rotating speed, initial immersed angle) on the film thickness. The result indicates that the film thickness has a strong dependency on the rotating speed, while the surface tension has negligible effect.

• 반도체디스플레이기술학회지
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• 제9권2호
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• pp.73-78
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• 2010

This research is about the drying and curing characteristic of conductivity metallic ink on-line curing device in order to improve the curing time for productivity in RFID Gravure printing. The curing process is carried out to increase the electric conductivity after the metallic ink is printed on the substrate. The metal ink is composed of nano-sized silver or copper particles. In this research, the combined IR and Hot air curing system is used and its results is compared with those of oven, IR and Hot Air type respectively. Generally the curing time in the past is about 3 minutes. But the combined system (IR+Hot Air) in this research shows that curing time is less than 30 seconds. These results is much faster than those of other system. This study can be help to make Roll-to-Roll drying and curing process for mass and continuous production on-line.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
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• pp.113.1-113.1
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• 2011

PEMS (printed electro-mechanical system) is fabricated by means of various printing technologies. Passive and active compo-nents in 2D or 3D such as conducting lines, resistors, capacitors, inductors and TFT(Thin Film Transistor), which are printed withfunctional materials, can be classified in this category. And the issue of PEMS is applied to a R2R process in the manu-facturing process. In many electro-devices, the vacuum process is used as the manufacturing process. However, the vacuum process has a problem, it is difficult to apply to a continuous process such as a R2R(roll to roll) printing process. In this paper, we propose an ESD (electro static deposition) printing process has been used to apply an organic solar cell of thin film forming. ESD is a method of liquid atomization by electrical forces, an electrostatic atomizer sprays micro-drops from the solution injected into the capillary with electrostatic force generated by electric potential of about several tens kV. ESD method is usable in the thin film coating process of organic materials and continuous process as a R2R manufacturing process. Therefore, we experiment the thin films forming of PEDOT:PSS layer and active layer which consist of the P3HT:PCBM. The organic solar cell based on a P3HT/PCBM active layer and a PEDOT:PSS electron blocking layer prepared from ESD method shows solar-to-electrical conversion efficiency of 1.42% at AM 1.5G 1sun light illumination, while 1.86% efficiency is observed when the ESD deposition of P3HT/PCBM is performed on a spin-coated PEDOT:PSS layer.

• 한국정밀공학회지
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• 제14권1호
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• pp.142-149
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• 1997

Ceramic-coated anilox roll for printing is resistant to corrosion and wear, and hence has enhanced life and quality. Laser engraving is used typically for machining holes to store ink in this roll. Since engraved hole size and shape are directly related to laser processing parameters, it is necessary to know the rela- tionships among these parameters. In this study, the parameters for engraving of ;oasma sprayed ceramic coatings with Nd:YAG laser were studied. Relationships between hole shape and processing parameters were analyzed. Cr$_{2}$O$_{3}$ceramic was found to be most suitable for Nd:YAG laser engraving. It was found that hole depth can be increased by using higher energy pulses. Effect of using different assistant gases was small to the final results. For better results, it was suggested to use a very stable laser with shorter pulses and higher pulse energy.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 춘계학술대회 논문집
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• pp.421-422
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• 2009

• 한국레이저가공학회:학술대회논문집
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• 한국레이저가공학회 1999년도 춘계학술발표대회 논문개요집
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• pp.39-42
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• 1999

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2279-2284
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• 2007

This study is intended to analyze the effect of thin ink-film thickness around rotating printing roll on the printing quality in the gravure printing process which is used for making electronics circuit like a RFID tag with a conductive ink. The present work numerically estimates the film thickness around rotating roller partially immersed in ink, for which the volume of fluid (VOF) method was adopted to figure out the film formation process around rotating roller. Parameter studies were performed to compare the effect of ink viscosity, surface tension, roller rotating speed, immersed angle on the film thickness. The result indicates that the film thickness has a strong dependency on the fluid viscosity, while the surface tension has negligible effect.

• 한국기계가공학회지
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• 제17권3호
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• pp.51-58
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• 2018

In this paper, the organic material Poly(methyl methacrylate) PMMA is used with inorganic $Al_2O_3$ to fabricate organic-inorganic multilayer barrier thin films. The organic thin films are developed using a roll-to-roll electrohydrodynamic atomization system, whereas the inorganic are grown using a roll-to-roll low-temperature atmospheric pressure atomic layer deposition system. For the first time, these two technologies are used together to develop organic-inorganic multilayer barrier thin films in atmospheric condition. The films are grown under optimized parameters and classified into three classes based on the layer structures, when the total thickness of the barrier is maintained at ~ 160 nm. All classes of barriers show good morphological, optical and chemical properties. The $Al_2O_3$ films with a low average arithmetic roughness of 1.58 nm conceal the non-uniformity and irregularities in PMMA thin films with a roughness of 5.20 nm. All classes of barriers show a notably good optical transmission of ~ 85 %. The hybrid organic-inorganic barriers show water vapor and oxygen permeation in the range of ${\sim}3.2{\times}10^{-2}g/m^2/day$ and $0.015cc/m^2/day$ at $23^{\circ}C$ and 100% relative humidity. It has been confirmed that it can be mass-produced and used as a low-cost barrier thin film in various printing electronic devices.

• 전기전자학회논문지
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• 제26권2호
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• pp.205-210
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• 2022

본 연구에서는 유기 발광 다이오드(OLED)의 광추출 향상을 위한 롤투롤 마이크로컨택(mCP)방식으로 인쇄된 마이크로렌즈 어레이(MLA)를 제시하였다. 상업적으로 사용되는 마이크로렌즈 어레이를 템플레이트로 사용하여서 polydimethylpolysiloxane(PDMS)를 롤스탬프로 제작하였다. 낮은 끓는 점을 가지는 불소화 잉크로부터 PDMS 롤스탬프에 고분자 박막을 형성하고 이를 OLED의 하부면에 고압·고온 처리 없이 인쇄하였다. 최적화된 농도를 찾아서 템플레이트로 사용된 MLA와 거의 동일한 모양의 패턴을 성공적으로 인쇄하였다. 마이크로컨택 방식으로 인쇄된 MLA의 구조와 소재의 낮은 흡수도로 인해서 OLED의 외부양자효율이 18% 향상되었다.

• 한국정밀공학회지
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• 제30권6호
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• pp.567-572
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• 2013

In many electro-devices, the vacuum process is used as the manufacturing process. However, the vacuum process has a problem, it is difficult to apply to a continuous process such as a R2R(roll to roll) printing process. In this paper, we propose an ESD (electro static deposition) printing process has been used to apply an organic solar cell of thin film forming. ESD is a method of liquid atomization by electrical forces, an electrostatic atomizer sprays micro-drops from the solution injected into the capillary with electrostatic force generated by electric potential of about several tens kV. The organic solar cell based on a P3HT/PCBM active layer and a PEDOT:PSS electron blocking layer prepared from ESD method shows solar-to-electrical conversion efficiency of 1.42% at AM 1.5G 1sun light illumination, while 1.86% efficiency is observed when the ESD deposition of P3HT/PCBM is performed on a spin-coated PEDOT:PSS layer.