• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.416-417
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• 2007

We prepared flexible transparent conducting electrodes by spray coating of single-walled carbon nanotube (SWNT) networks on PET substrate and have demonstrated their use as transparent anodes for flexible organic light emitting diodes (OLEDs). The flexible CNT electrode produced by spray coating method shows relatively low sheet resistance ($150{\sim}220{\Omega}/sq.$) and high transmittance of ~60% even though it was prepared at room temperature. In addition, CNT electrode/PET sample exhibits little resistance change during 2000 bending cycles, demonstrated good mechanical robustness. Using transparent CNT electrode, it is readily possible to achieve performances comparable to commercial ITO-based OLEDs. This indicates that flexible CNT electrode is alternative anode materials for conventional ITO anode in flexible OLEDs.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.431-433
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• 2009

We developed 4.8 inch WQVGA e-paper on plastic substrate using organic field effect transistors (OFETs). Polyethylene naphthalate (PEN) film was used as a flexible substrate and arrays of OFETs with bottom-gate, bottom-contact structure were fabricated on it. Lowtemperature curable organic gate insulating materials were employed and polymer semiconductor solutions were ink-jetted on arrays with high-resolution. At all steps, process temperature was limited below $130^{\circ}C$. Finally, we could drive flexible e-paper displays based on OFET arrays with the resolution of 100 dpi.

• 반도체디스플레이기술학회지
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• 제20권4호
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• pp.49-54
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• 2021

The display industry is transitioning from traditional rigid products such as flat panel displays to flexible or wearable ones designed to be folded or rolled. Accordingly, colorless and optically transparent polyimide (CPI) films are one of the prime candidates to substitute traditional cover glass as a passivation layer to accommodate product flexibility. However, CPI films subjected to repetitive pure bending loads inevitably entail an accumulation of residual strain that can eventually cause wrinkles or delamination in the underlying component after a certain number of static and cyclic loading. The purpose of this study is to establish an experimental method to systematically evaluate the bending residual strain of CPI films. Films were monotonically and cyclically wrapped on mandrels of various diameters to ensure a constant strain in each. After unwrapping the wound CPI film, the residual radius of curvature remaining on the film was measured and converted into residual strain. The critical radius of curvature at which residual strain does not remain was about 5 mm, and the residual strain decreased in proportion to the log time. It is expected that flexible displays can be reliably designed using the data between the applied bending strain and the residual strain.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.63-66
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• 2006

We describe a unique process based on colloidal self-assembly that results in a uniform (almost hexagonally close-packed) layer of liquid crystal domains over large areas leading to single-substrate cholesteric LCDs with low switching voltages, excellent contrast, and high brightness. Extension to guest-host LCDs is also discussed.

• 한국고분자학회지:고분자과학과기술
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• 제22권3호
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• pp.237-241
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• 2011

• Elastomers and Composites
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• 제47권4호
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• pp.272-281
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• 2012

최근 주목을 받고 있는 유연성/신축성 전극소재는 유연디스플레이, 센서, 유전탄성고분자 액추에이터 및 제너레이터, 스마트 수술도구 등과 같은 다양한 분야에서 활용이 가능하다. 유연성/신축성 전극소재는 다양한 형태의 기계적인 변형을 받게 되는데 이때 기계적인 변형에 맞춰 함께 변형될 뿐만 아니라 신축되어야 한다. 따라서 기계적 변형에서도 전극으로써 기능을 유지해야 하기 때문에 대단히 어려운 연구분야라 할 수 있다. 본 총설에서는 최근까지 연구된 유연성/신축성 전극소재의 제조와 특성을 소개하고자 한다.

• Journal of Information Display
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• 제10권3호
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• pp.131-136
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• 2009

This is a report on the fabrication of a flexible OTFT backplane for electrophoretic display (EPD) using a printing technology. A practical printing technology for a polycarbonate substrate was developed by combining the conventional screen and inkjet printing technologies with the wet etching and oxygen plasma processes. For the gate electrode, the screen printing technology with Ag ink was developed to define the minimum line width of ${\sim}5{\mu}m$ and the thickness of ${\sim}70nm$ with the resistivity of ${\sim}10^{-6}{\Omega}{\cdot}cm$, which are suitable for displays with SVGA resolution. For the source and drain (S/D) electrodes, PEDOT:PSS, whose conductivity was drastically enhanced to 450 S/cm by adding 10 wt% glycerol, was adopted. In addition, the modified PEDOT:PSS could be neatly confined in the specific S/D electrode area that had been pretreated with oxygen. The OTFTs that made use of the developed printing technology produced a mobility of ${\sim}0.13cm^2/Vs.ec$ and an on/off current ratio of ${\sim}10^6$, which are comparable to those using thermally evaporated Au for the S/D electrode.

• 한국전기전자재료학회논문지
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• 제19권6호
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• pp.552-557
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• 2006

Electrical, optical, surface, and structural properties of amorphous indium-zinc-oxide (a-IZO) grown by box cathode sputtering (BCS) were compared with crystalline indium-tin-oxide (c-ITO) anode films grown by conventional DC sputtering (DCS). Although x-ray diffraction plot of BCS-grown IZO film shows amorphous structure, the optical and electrical properties of a-IZO is comparable to those of c-ITO film. In particular, BCS-grown IZO films shows very smooth surface without defects such as pin hole and cracks because most of the energy of the sputtered atoms was confined in high density plasma region in box cathode gun. Furthermore polymer organic light emitting diodes (POLED) with the a-IZO anode film shows better electrical properties than that of POLED with the c-ITO anode film due to high work function and smooth surface of a-IZO. This suggested that BCS-grown a-IZO film is promising anode materials substituting conventional c-ITO anode in OLED and flexible displays.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.232.1-232.1
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• 2014

The green displays are the human friendly displays, the nature friendly displays, and the economical displays. Electrochromic displays are low cost and environmental devices because they do have more choice of colours and use much less power. The elements of the electrochromic devices consist of at least two conductors, an electrochromic material and an electrolyte. The optical properties were obtained using the optical contrast between the transparency of the substrate and the coloured state of the electrochromic materials. These devices can be fully flexible and printable. Due to the characteristics of the high coloration efficiency and memory effects, the electrochromic devices have been used in various applications such as information displays, smart windows, light shutters and electronic papers. Among these technical fields switchable mirrors have been received much attention in the applicative point of view of various electronic devices production. We have developed a novel silver (Ag) deposition-based electrochromic device for the reversible electrodeposition (RED) system. The electrochromic device can switch between transparent states and mirror states in response to a change in the applied voltage. The dynamic range of transmittance percent (%) for the fabricated device is about 90% at 550 nm wavelength. Also, we successfully fabricated the large area RED display system using the parted electrochromic cells of the honey comb structure.

• 한국콘텐츠학회논문지
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• 제17권3호
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• pp.74-87
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• 2017

본 연구는 아직 제품으로 등장하지 않은 플렉시블 디스플레이 기반의 소형 원통형 디스플레이를 위한 사용자 정의 기반의 핸드 제스처 도출을 목표로 한다. 이를 위하여 먼저 소형 원통형 디스플레이의 크기와 기능을 정의하고, 해당 기능 수행을 위한 태스크를 도출하였다. 이후 가상의 원통형 디스플레이 인터페이스와 이를 조작하기 위한 물리적 오브젝트를 각각 구현하여 사용자들이 실제 원통형 디스플레이를 조작하는 것과 유사한 환경을 제작하였고, 제스처 도출을 위한 태스크를 수행했을 경우 발생하는 결과를 가상의 원통형 디스플레이에 제시하여 사용자들이 해당 조작에 적합하다고 판단되는 제스처를 정의할 수 있도록 하였다. 도출된 각 태스크 별 제스처 그룹에서 빈도수를 토대로 대표 제스처를 선정하였으며, 각 제스처에 대한 의견 일치 점수를 도출하였다. 마지막으로 제스처 분석 및 사용자 인터뷰를 기반으로 제스처 도출에 활용되는 멘탈 모델을 관찰 하였다.