• Electronics and Telecommunications Trends
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• v.30 no.6
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• pp.1-11
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• 2015

최근 디스플레이 산업은 Liquid Crystal Display(LCD)산업의 성숙 및 동북아 선도업체를 중심으로 과점화 양상에 따라, 국가 간 주도권 경쟁을 위한 경쟁 치열해지고 있으며, 디스플레이 시장정체 극복 및 경쟁국 간의 기술시장의 우위를 선점하기 위하여 차세대 디스플레이 개발을 추진하고 있다. 차세대 디스플레이는 기능이 다양화 된 디스플레이, Active Matrix Organic Light Emitting Diode(AMOLED), 플렉서블 디스플레이, 투명 디스플레이와 같은 새로운 디스플레이 및 자동차 교육, 광고 의료 분야와 융합되는 신시장 창출형 융합 디스플레이로 발전하고 있다. 본고에서는 차세대 디스플레이의 최근 기술동향 및 디스플레이 국제 표준 기술동향 및 이슈를 살펴보고자 한다.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.588-591
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• 2004

Polyazomethine type conjugated copolymers containing phenanthridine units, poly(PZ-PTI), were synthesized by Schiff-base reaction. This new conjugated copolymer exhibited improved solubility in common organic solvents due to the presence of alkyl side chains as well as phenanthridine groups. Double layer (ITO/poly(PZ-PTI)/$Alq_3$/Mg) light emitting diode (LED) exhibited enhanced EL emission and efficiency compared to that of single layer (ITO/poly(PZ-PTI)/Mg) LED. With increasing the thickness of $Alq_3$ layer in double layer (ITO/poly(PZ-PTI)/$Alq_3$/Mg) LED the emission peak gradually shifted to the single layer (ITO/$Alq_3$/Mg) LED, confirming good hole transporting behaviour of the synthesized conjugated copolymer.

• Journal of the Microelectronics and Packaging Society
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• v.22 no.1
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• pp.7-14
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• 2015

Recently, advances in nano-material researches have opened the door for various transparent conductive materials, which include carbon nanotube, graphene, Ag and Cu nanowire, and printable metal grids. Among them, Ag nanowires are particularly interesting to synthesize because bulk Ag exhibits the highest electrical conductivity among all metals. Here we reviewed recently-published research works introducing various devices from organic light emitting diode to tactile sensing devices, all of which are employing AgNW for a conducting material. They proposed methods to enhance the stretchability and reversibility of the transparent electrodes, and apply them to make various flexible and stretchable electronics. It is expected that Ag nanowires are applicable to a wide range of high-performance, low-cost, stretchable electronic devices.

• Journal of Information Display
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• v.9 no.2
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• pp.5-8
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• 2008

Bottom gate thin film transistors (TFTs) with microcrystalline and amorphous Si (a-Si) double active layers (DAL) were fabricated. Since the process of DAL TFTs can use that of conventional a-Si TFTs, these DAL TFT process has advantages, such as low cost, large substrate, and mass production capacity. In order to analyze the degradation characteristics in saturation region for driving TFTs of active matrix organic light emitting diode, three different dynamic stresses were applied to DAL TFTs and a-Si TFTs. The threshold voltage shift of DAL TFTs and a-Si TFTs during 10,000 second stress is 0.3V and 2V, respectively. DAL TFTs were more reliable than a-Si TFTs.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.215-217
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• 2006

This paper presents an area efficient 8-bit current digital to analog convector (DAC) which is applied to 240 channels Active Matrix - Organic Light Emitting Diode (AMOLED) data driver. The proposed circuit constitutes 4-bit binary weighted current DAC and 4-bit switched capacitor cyclic DAC. The proposed DAC has about 70% smaller area than that of the typical binary weighted current DAC. We overcome sampling time by reducing the number of repetition phases so that it can display 8-bit gray scale image.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.185-189
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• 2002

Flexible displays such as plastic based LCDs and organic light-emitting diodes for mobile communication devices have been researched and developed at KETI in KOREA since 1997. The Plastic film substrate has so poor thermal tolerance and non-rigidness that the fabrication of active devices and panel assembly have to perform at low temperature and pressure. In addition, high thermal expansion of the substrate is also a serious problem for reliable metallic film deposition. In this paper, we investigated particularly on the fundamental characteristics of various plastic substrates and then, suggested novel methods that improve the fabrication processes of plastic LCD panel. In order to maintain stable substrate surface and uniform cell gap during panel assembly, we utilized newly-invented iii and vacuum chuck. Electro-optical characteristics of fabricated plastic LCD are better than or equivalent to those of typical glass based LCDs though it is thinner, lighter-weight and more robust.

• Transactions on Electrical and Electronic Materials
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• v.4 no.2
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• pp.10-14
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• 2003

Flexible displays such as plastic-based liquid crystal displays (LCDs) and organic light-emitting diode displays (OLEDDs) have been researched and developed at KETI since 1997. The plastic film substrate is very weak to heat and pressure compared to glass substrate, that its fabrication process is limited to 110$^{\circ}C$ and low pressure. The ITO films were deposited on the bare plastic film substrate by rf-magnetron sputtering. Moreover, in order to maintain uniform cell gap and pressure on the plastic film substrate, we utilized newly-invented jig and fabrication process. Electro-optical characteristics were better than or equivalent to those of typical glass LCDs though it is thinner, lighter-weight, and more robust than glass LCDs.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.163-163
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• 2012

차세대 모바일용 전자디스플레이로 각광받고 있는 FOLED (flexible organic light emitting display)의 연구에서 display의 신뢰성과 수명은 매우 중요한 연구 테마이다. OLED의 수명단축에 영향을 미치는 요소는 수분에 의한 열화가 가장 치명적이다. Barrier layer를 통한 수분의 주요 침투경로는 pin-hole과 void 등과 같은 defect에 의한 것으로 보인다. 수분의 침투 경로를 제어하는 OLED용 barrier layer의 요구조건은 WVTR (water vapor transmission rate)이 $10^{-6}g/m^2{\cdot}day$ 이하로 낮아야 한다. Barrier layer가 가져야 할 핵심적인 조건은 유연성을 가지면서 동시에 WVTR 값이 매우 낮아야 하는데, 아직까지 이를 만족하는 barrier layer의 개발은 아직 덜된 실정이다. 본 연구에서는 PET (polyethylene terephthalate) 기판에 sputtering법으로 barrier layer를 제조하였다. 증착에 이용한 타겟은 두가지 종류인 Al과 $Al_2O_3$를 사용하였으며, 다층박막으로 제조하였다. 제조된 barrier layer의 수분침투 특성은 WVTR의 측정으로, 유연성의 평가는 in-situ fatigue test를 수행하여 측정하였다. 종합적인 특성 평가를 위하여 SEM과 AFM (atomic force microscope) 관찰도 하였다.

• Journal of the Semiconductor & Display Technology
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• v.4 no.3 s.12
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• pp.17-22
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• 2005

LED lamp was designed by the serial-parallel integration of LED chips in metal-interconnection. The 7 $4.5{\times}4.5\;in^{2}$ masks were designed with the contact type of chrome-no mirror?dark. The white epitaxial thin film was grown by metal-organic chemical vapor deposition. The active layers were consisted with the serial order of multi-quantum wells for blue, green and red lights. The fabricated LED chip showed the electroluminescence peaked at 450, 560 and 600 nm. For the current injection of 20 mA, the operating voltage was measured to 4.25 V and the optical emission power was obtained to 0.7 $\mu$W.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2006.05a
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• pp.259-264
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• 2006

ITO 투명전도막은 현재 FPD(flat panel display)소자의 전극으로 사용되고 있다. 특히 근래에 많은 연구가 진행되고 있는 유기발광다이오드(organic light emitting diode: OLED) 소자의 제작에 투명전도막으로 많은 응용이 되고 있다. ITO 를 이용한 디스플레이 소자는 ITO 의 계면 상태와 전기적 특성에 따라 그 특성이 크게 변한다. 본 연구에서는 $O_2$ 플라즈마 처리를 통하여 ITO 투명전도막의 전기적 특성 및 표면상태의 변화에 대하여 조사하고, 이러한 특성 변화에 따라 현재 많은 연구가 진행되고 있는 OLED 소자의 제작에 응용하기 위하여 유기용액을 이용한 접촉각 측정을 통하여 $O_2$ 플라즈마 처리에 따른 ITO 투명전도막과 유기용액의 접착력에 대하여 고찰하였다.