• 기계와재료
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• 제22권3호
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• pp.30-35
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• 2010

최근 전자소자의 제조공정에 있어서 인쇄전자를 적용하여 고가이면서 화학물질이 많이 배출되는 기존의 제조공정을 대체하기 위한 연구가 활발하게 이루어지고 있다. 인쇄전자를 적용하기 위해서는 기존 공종 대비 생산비의 절감과 대량생산을 요구하고 있으며, 그 요구를 만족시킬 수 있는 인쇄전자 기술로는 롤투롤(R2R, Roll to Roll) 인쇄방식이 대표적이라 할 수 있다. 롤투롤 인쇄방식과 그라비아(Gravure)/그라비아옵셋(Gravure offset) 인쇄방법을 적용하면 낮은 비용으로 대량의 전자소자 생산에 쉽게 접근 할 수 있다. (주)펨스는 인쇄전자 기술의 활성화를 위하여 롤투롤-그라비아/그라비아옵셋 인쇄를 적용한 인쇄전자소자용 인쇄, 코팅장비를 개발 제작하고 있다.

• 한국정밀공학회지
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• 제30권6호
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• pp.578-583
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• 2013

The lighting devices using organic light emitting diodes (OLEDs) are actively researched because of the various advantages such as high power efficiency and 2-dimensitonal lighting emitting. To commercialize those OLED lighting devices, the manufacturing cost must be downed to comparable price with conventional light sources. Here, we demonstrate a reverse gravure-offset or gravure off-set printed metal electrode for the auxiliary electrode for OLED lighting devices. For the fabricated OLED's auxiliary electrode, we used Ag nano-paste and printed metal grid structure with a line width and spacing of several ten and hundred micrometer by using gravure-offset printing. In the end the printing metal grid pattern are successfully achieved by optimization of various experimental conditions such as printing pressure, printing speed and printing delay time.

• 한국정밀공학회지
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• 제27권9호
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• pp.16-19
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• 2010

This paper presents how to design and fabricate the gravure offset printing system for enhancement of register precision. Factors of precision error are caused by imprecision of gravure plate, deformation of substrate, printing quality change due to the change of ink viscosity, Imprecision of printing machine, and so on. This study suggests concept design of gravure offset printing system which is able to minimize or remove these error factors.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 추계학술대회 논문집
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• pp.717-718
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• 2008

• 한국정밀공학회지
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• 제29권1호
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• pp.19-24
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• 2012

We demonstrate the desert beetle back mimicking hybrid superhydrophilic/superhydrophobic patterned surface by using the combination method of colloidal lithography and gravure offset printing for nano and micro patterning, respectively. The two methods are cost-effective and industrially available techniques compared to the other nano/micro patterning methods. To verify the water collecting function of the hybrid surface, the water condensation behavior is investigated on the chilled surface in ambient temperature and high humidity. Due to the synergetic effect of drop and film wise condensation, the hybrid superhydrophobic/superhydrophilic surface shows the higher efficiency than one of single wettability surfaces. The work is underway to get the good patterns of hybrid surfaces for water collecting from the dew or fog.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 춘계학술대회 논문집
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• pp.961-962
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• 2008

• 한국정밀공학회지
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• 제28권10호
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• pp.1146-1152
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• 2011

Ink transfer process is very important to determine quality of printed pattern, therefore its mechanism should be understood to control printing quality. Although there have been many attempts to understand ink transfer mechanism by numerical simulation and experimental studies, their model was too much simple to model realistic printing process and our understanding is not enough yet. In this paper we designed ink transfer visualization system to present flow visualization of ink transfer process for gravure offset printing. We considered rotational effect of blanket roll which is related with printing speed and used non-Newtonian fluid as working fluid such as Ag paste. For printing unit, cantilever-type blanket roll is used for convenient visualization of ink transfer. Serial images were captured continuously by using high-speed CMOS camera and long range microscope. We investigated the effects of various design parameters such as printing speed and pattern angle on the ink transfer process. We found more stretched ink filament for non-Newtonian fluid than Newtonian fluid. As increasing printing speed, length of stretched ink filament and height of break-up point are also increased. We also compared ink transfer process between CD and MD pattern and its relationship with ink transfer mechanism.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1098-1102
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• 2008

To increase the ink transfer rate in the micro-gravure-offset printing, the liquid transfer process between two separating plates is investigated. During the liquid transfer process, in which one plate is fixed and the other one moves vertically, a sessile droplet is separated into two droplets. The volume ratio of the two droplets depends on the contact angles of the two plates. In a numerical study of the ink transfer processes, liquid transfer between two parallel separating plates and between a trapezoidal cavity and an upward moving plate are simulated, as models of the printing of ink from the offset pad onto the substrate and the picking up of ink from the gravure plate by the offset pad, respectively. Also, in experimental study, to obtain various surface contact angles, chemical treatment, plasma treatment, and electrowetting- on-dielectric (EWOD) surface are considered. The transfer rate between two plates is calculated by analyzing the droplet images. From the results, the optimal surface contact angles of the units of the micro-gravure-offset printing can be characterized.