• Title/Summary/Keyword: Protective Layer

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Mechanical Modeling of Pen Drop Test for Protection of Ultra-Thin Glass Layer (초박형 유리층 보호를 위한 펜 낙하 시험의 기계적 모델링)

  • Oh, Eun Sung;Oh, Seung Jin;Lee, Sun-Woo;Jeon, Seung-Min;Kim, Taek-Soo
    • Journal of the Microelectronics and Packaging Society
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    • v.29 no.3
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    • pp.49-53
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    • 2022
  • Ultra-thin glass (UTG) has been widely used in foldable display as a cover window for the protection of display and has a great potential for rollable display and various flexible electronics. The foldable display is under impact loading by bending and touch pen and exposed to other external impact loads such as drop while people are using it. These external impact loads can cause cracks or fracture to UTG because it is very thin under 100 ㎛ as well as brittle. Cracking and fracture lead to severe reliability problems for foldable smartphone. Thus, this study constructs finite element analysis (FEA) model for the pen drop test which can measure the impact resistance of UTG and conducts mechanical modeling to improve the reliability of UTG under impact loading. When a protective layer is placed to an upper layer or lower layer of UTG layer, stress mechanism which is applied to the UTG layer by pen drop is analyzed and an optimized structure is suggested for reliability improvement of UTG layer. Furthermore, maximum principal stress values applied at the UTG layer are analyzed according to pen drop height to obtain maximum pen drop height based on the strength of UTG.

Effect of $Al_2O_3$ capping layer on properties of MgO protection layer for plasma display panel

  • Eun, Jae-Hwan;Lee, Jung-Heon;Kim, Soo-Gil;Kim, Hyeong-Joon
    • 한국정보디스플레이학회:학술대회논문집
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    • 2002.08a
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    • pp.628-631
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    • 2002
  • $Al_2O_3$ capping layer and MgO protective layer were deposited by electron beam evaporation method using single crystal source. Thickness of the capping layer, $Al_2O_3$, was varied from 5 nm to 10 nm. Surface morphology was observed by SEM and AFM before and after hydration. And microstructure of deposited $Al_2O_3$ layer and chemical shift of electron binding energy were also observed by high resolution TEM and XPS, respectively, after hydration. From these results, it was found that Mg atoms diffused into $Al_2O_3$ layer, reacted with moisture and formed $Mg(OH)_2$ during hydration. As thickness of $Al_2O_3$ increased, extent of hydration increased. $Al_2O_3$ capped MgO thin films and uncapped MgO thin films were deposited on AC-PDP test panel to characterize discharge properties. Although $Al_2O_3$ has poor discharge properties rather than MgO, because of many hydrated species on the surface of MgO, similar discharge properties were observed.

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Electrical Properties of MgO Films as a Protective Layer for AC PDPs (AC PDP 보호막 doped MgO 박막의 전기적 특성)

  • Kim, Chang-Il;Jung, Young-Hun;Lee, Young-Jin;Paik, Jong-Hoo;Choi, Eun-Ha;Jung, Seok;Kim, Jeong-Seok
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.06a
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    • pp.155-155
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    • 2009
  • AC-PDP의 유전체 보호막 물질로 사용 종인 다결정 MgO의 전기적 특성을 개선하기 위하여 본 연구에서는 MgO에 doping 물질과 첨가량에 따른 전기적 특성을 고찰하였다. 박막을 증착시키기 위해 MgO pellet target을 만드는데 이때 pellet의 밀도, XRD, 비커스경도, 파괴인성, 표면 grain size와 이차전자방출계수와의 관계 및 박막의 표면거칠기, 표면의 형태, 투과율과 이차전자방출계수와의 관계를 고찰하였다. 이에 여러 dopant를 첨가하여 특성 평가한 실험데이터를 정리하여 이차전자방출계수와의 연계성을 조사 하였다.

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Review on Molecular Simulation of Graphene from a Tribological Perspective (트라이볼로지 관점에서의 그래핀 분자시뮬레이션 연구동향)

  • Kim, Hyun-Joon;Chung, Koo-Hyun
    • Tribology and Lubricants
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    • v.36 no.2
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    • pp.55-63
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    • 2020
  • Recently, graphene has attracted considerable attention owing to its unique electrical, optical, thermal, and mechanical properties. The broad spectrum of applications from optics, sensors, and electronics to biodevice have been proposed based on these properties. In particular, graphene has been proposed as a protective coating layer and solid lubricant for microdevices and nanodevices because of its high mechanical strength, chemical inertness, and low friction characteristics. During the past decade, extensive efforts have been made to explore the tribological characteristics of graphene under various conditions and to expand its applicability. In addition to the experimental approaches, the molecular simulations performed provide fundamental insights into the friction and wear characteristics of graphene resulting from molecular interactions. This work is a review of the studies conducted over the past decade on the tribological characteristics of graphene using molecular simulation. These studies demonstrate the principal mechanisms of the superlubricity of graphene and help clarify the influences of surface conditions on tribological behavior. In particular, the investigation of the effects of the number of layers, strength of adhesion to the substrate, surface roughness, and commensurability provides deeper insights into the tribological characteristics of graphene. These fundamental understandings can help elucidate the feasibility of graphene as a protective coating layer and solid lubricant for microdevices and nanodevices.

Electro-optical characteristics of MgO protective layer after RF plasma treatment using Ar, $O_2$ and $H_2$ gases

  • Son, Chang-Gil;Lee, H.J.;Jung, J.C.;Park, W.B.;Moon, M.W.;Oh, P.Y.;Jeong, J.M.;Ko, B.D.;Lee, J.H.;Lim, J.E.;Han, Y.G.;Lee, S.B.;Yoo, N.L.;Jeong, S.H.;Choi, E.H.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07b
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    • pp.1211-1214
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    • 2005
  • One of the important problems in recent AC-PDP technology is high efficiency. In this research, we have been investigated electro-optical characteristics of MgO protective layer after radio frequency(RF) plasma treatment using Ar, $O_2$, and $H_2$ gases. The breakdown voltage order was $O_2$ > Ar > Nontreatment > $H_2$. Also, brightness order was $O_2$ > Ar > Non-treatment > $H_2$. In this experiment, the best result was obtained after $O_2-plasma$ treatment.

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