• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2050-2051
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• 2008

디스플레이 산업이 급속도로 발전함에 따라 touch screen 및 panel에 사용되고 있는 ITO(Indium Tin Oxide)박막의 표면저항에 대한 정밀 측정이 요구되고 있으며, 표면저항 측정은 주로 FPP(Four-Point Probe) 원리를 이용한 측정기를 사용하고 있다. 대부분의 면저항 측정기는 single 방식을 적용하고 있으나 이 방식은 가장자리 효과가 크며, 시료의 크기 및 두께와 핀 간격에 대한 보정계수를 적용하여야 하는 단점이 있다. 본 연구는 가장자리 효과가 거의 없고, 보정계수를 적용할 필요가 없는 dual 방식을 적용한 표면저항 측정기를 개발하였다. 개발된 표면저항 측정기는 휴대용으로 누구나 쉽고 정확하게 사용할 수 있으며, 측정 정확도는 지시값의 1.0 % 이하이고, 측정범위는 $4m{\Omega}/sq{\sim}20k{\Omega}/sq$ 이다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.239-240
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• 2014

$In_2O_3$에 Sn이 도핑된 Indium Tin Oxdie (ITO)는 높은 전기전도성 및 광투과율을 가지므로 터치센서, 태양전지, 스마트 윈도우, 플렉시블 디스플레이등의 수많은 광전자 소자에 필수적이다. 특히 스마트산업이 발전함에 따라 Touch Screen Panel (TSP) 에 적용되는 터치용 고품질 초박막 ITO의 수요가 증가하고 있다. 그러나 초박막 ITO 필름은 얇은 두께로 인해 낮은 결정성을 가지기 때문에 높은 전기전도성을 확보하기 힘들다. 따라서 본 연구에서는 결정성을 향상시키기 위하여 초기 박막 성장 메커니즘에 영향을 주는 인자를 제어하는데 목표를 두었으며 이러한 박막 초기의 성장에 영향을 미치는 인자들 중 자장강도를 변화시킴으로써 플라즈마 임피던스를 조절하였다. 그 결과 전기적 특성 및 광학적 특성은 자장강도에 매우 의존함을 확인할 수 있었다.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.409-412
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• 2007

A lot of research for system-on-panel(SOP) have been done to integrate display systems including data driver, gate driver, timing controller, DC-DC converter, and smart functions such as embedded touch screen, ambient brightness sensing and luminance control, finger printing on the glass. Recently, the cost of an one-chip driver IC with various functions has decreased rapidly, and new mobile display interface technologies have been introduced. So it is necessary to examine the feasibility of SOP for practical mobile applications. In this paper, we will re-examine LTPS technologies for mobile displays in terms of various aspects and discuss the practical limitations on SOP technology and future technology trend of mobile displays.

• Current Optics and Photonics
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• v.1 no.1
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• pp.45-50
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• 2017

Optical instruments based on polymer-dispersed liquid crystal (PDLC) have been used to inspect transparent electrodes. Generally the operating voltage of an inspection instrument using PDLC is very high, over 300 V, reducing its lifetime and reliability. The operating-voltage issue becomes more serious in the inspection of touch-screen panel (TSP) electrodes, due to the bezel structure protruding over the electrodes. We have theoretically calculated the parameters affecting the operating voltage as a function of the distance between the TSP and the PDLC, the thickness, and the dielectric constant of the sublayers when the inspection module was away from the TSP electrodes. We have experimentally verified the results, and have proposed a way to reduce the operating voltage by substituting a plastic substrate film with a hard coating layer of smaller thickness and higher dielectric constant.

• Clean Technology
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• v.22 no.4
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• pp.232-240
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• 2016

Recently, various research studies have been conducted and many are in progress for the suitable alternative materials for ITO based touch screen panel (TSP) due to limitations in size and flexibility. Various researches from all over the world have been attempted to fabricate the fine electrode less than $5{\mu}m$ for the rapid developing of display technology. Research is also being carried out in metal mesh methods using the existing technologies and alternative materials at commercial level. However, by using the existing technologies certain discrepancies are observed like low transparency and low yield which also results in the distortion of patterns. For repairing the damaged pattern, the conventional laser CVD technique has also been used but there are some challenges observed in CVD technique like achieving a stable fine electrode of $10{\mu}m$ or less and avoiding the formation of satellite drops. To overcome these issues, a new printing process named Electrohydrodynamic (EHD) printing, has been introduced by which $5{\mu}m$ fine patterns can be printed in one step. This EHDA printing technique has been applied to print very fine electrodes of $5{\mu}m$ or less by using conductive inks of various viscosities. This study also presents the optimized process parameters for printing $5{\mu}m$ fine electrode patterns during experiments by controlling the applied voltage and supply flow rate. The $5{\mu}m$ repair electrodes were fabricated for repairing $50{\mu}m$ shorted electrode samples.

• Clean Technology
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• v.18 no.1
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• pp.69-75
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• 2012

In this study, we executed an environmental impact assessment about recycling of ITO (Indium Tin Oxide), used for touch panel. ITO is mainly used to make transparent conductive coatings for touch and flat screen LCD (Liquid Crystal Display), ELD (Emitting Light Device), PDP (Plasma Display Panel). This demand is increasing little by little. but form current status, ITO is discarded than recycling. It is important to recycling ITO for national strategies about resource conservation, and reduce environmental burden. Also Landfill or incineration of ITO cloud be harmful to the human health in the long-term. Material Life Cycle Assessment method (MLCA) was conducted for comparison landfill and recycling of ITO. MLCA would provide more information for environmental issues and potential environmental impacts of ITO. The study includes two scenarios, the basic scenario is recycling of ITO (10, 20, 30%) and the other scenario is landfill of ITO. In addition, amount of carbon dioxide and energy were calculated.

• Journal of the Korean institute of surface engineering
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• v.42 no.1
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• pp.21-25
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• 2009

Using an evaporation system, $SiO_2$ was deposited as a buffer layer between a PET substrate and a ITO layer and then ITO/$SiO_2$/PET layers were annealed for 1.5 hours at the temperature of $180^{\circ}C$. Adhesion and electro-optical properties of ITO films were studied with thickness variance of a $SiO_2$ buffer layer. As a result of introduction of the $SiO_2$ buffer layer, sheet resistance and resistivity increased and a ITO film with optimum sheet resistance ($529.3{\Omega}/square$) for an upper ITO film of resistive type touch panel could be obtained when $SiO_2$ of $50{\AA}$ was deposited. And it was found that ITO films with $SiO_2$ buffer layer have higher transmittance of $88{\sim}90%$ at 550 nm wavelength than ITO films with no buffer layers and the transmittance was enhanced as $SiO_2$ thickness increased from $50{\AA}$ to $100{\AA}$. Adhesion property of ITO films with $SiO_2$ buffer layers became better than ITO films with no buffer layers and this property was independent of $SiO_2$ thickness variance ($50{\sim}100{\AA}$). By depositing a $SiO_2$ buffer layer of $50{\AA}$ on the PET substrate and sputtering a ITO thin film on the layer, a ITO film with enhanced adhesion, electro-optical properties could be obtained.

• The Journal of the Convergence on Culture Technology
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• v.7 no.1
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• pp.662-667
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• 2021

Vibrotactile feedback is a major function of the latest touch displays, which greatly improves the user's operability and immersion when interacting with the interface on the screen. In this study, we propose a vibrotactile actuator suitable for mounting on the back side of a mid- to large-sized display because it can generate a strong vibration output by applying an electrostatic force-based mechanism and can be manufactured in a thin flat panel type. The proposed actuator was developed in a structure capable of amplifying the vibration force by alternating up and down with electrostatic force by the upper and lower electrodes that are spaced apart from the electrically grounded mass suspended from a radial leaf spring. As a result of the performance evaluation, the developed bar-type module with two built-in actuators showed excellent vibration output of up to 3.3 g at 170 Hz, confirming the possibility of providing haptic feedback in medium and large touch displays.

• Current Photovoltaic Research
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• v.3 no.2
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• pp.50-53
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• 2015

Indium (In) is widely used for transparent electrodes of photovoltaics as a form of indium tin oxide (ITO) due to its superior characteristics of environmental stability, relatively low electrical resistivity and high transparency to visible light. However, In has been worn off in proportion to growth the In related market, and it leads to raise of price. Although In is obtained from ITO target scarps, much harmful elements are used for the recycling process. To decrease of harmful elements, ITO swarf particles obtained from target scraps was characterized whether it is feasible to transparent conductive oxide (TCO). The ITO swarf was crushed with milling process, and it was mixed with new ITO nanoparticles. The mixed particles were well dispersed into ink solvent to make-up an ink, and it was well coated onto glass substrate. After heat-treatment at $400^{\circ}C$ under $N_2$ rich environments, optical transmittance at 550 nm and sheet resistance of the ITO ink coated layer was 71.6% and $524.67{\Omega}/{\square}$, respectively. Therefore, it was concluded that the ITO swarf was feasible to TCO of touch screen panel.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.336.2-336.2
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• 2014

Indium Tin Oxide (ITO) thin films are used as the Transparent Conducting Oxide (TCO), such as flat panel display, transparent electrodes, solar cell, touch screen, and various optical devices. ZnO has attracted attention as alternative materials to ITO film due to its resource availability, low cost, and good transmittance at the visible region. Recently, very thin film deposition is important. In order to minimize the damage caused by bending. However, ZnO thin film such as Ga-doped ZnO(GZO) has poor sheet resistance characteristics. To solve this problem, By adding the conductive metal on films can decrease the sheet resistance and increase the mobility of the films. In this study, We analyzed the electrical and optical characteristics of GZO/Ag/GZO (GAG) films by change in Ag and GZO thickness.