• Title/Summary/Keyword: Liquid crystal displays

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Effect of Carbon Nanotube Concentrations on Residual DC of a Twisted Nematic Liquid Crystal Cell (탄소 나노 튜브 함량에 따른 TN 액정 셀의 잔류 DC 연구)

  • Baik, In-Su;Park, Kyung-Ah;Jeon, Sang-Youn;An, Kay-Hyeok;Lee, Seung-Hee;Lee, Young-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.11a
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    • pp.297-298
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    • 2005
  • We have fabricated twisted nematic (TN) liquid crystal cells doped by carbon nanotubes (CNTs) with different CNT wt. %. With a minute amount doping, multi-walled CNTs did not perturb the liquid crystal orientations at the off- and on-state. The hysteresis studies of voltage-dependent capacitance (V-C) under the influence of electric field generated by ac and dc voltage show that the residual do, which is tightly related to image sticking problem in liquid crystal displays, is greatly reduced due to ion trapping by CNTs. Also, the V-C hysteresis shows dependency of capacitance on concentration of multi-walled CNTs.

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Energy Reduction in LCD Displays

  • Liu, Tao;O'Neill, Mark;Hoffman, Kevin M.;Sanford, Quinn D.;Serres, Alan M.;Schiller, Robert
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.780-783
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    • 2008
  • Low-loss optical films can be used in LCD backlights to improve the display efficiency. Improvements can be used to enhance display performance, increase functionality and reduce energy costs.

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Experiments and analysis of droplet formation influenced by driving waveform (구동파형에 따른 잉크액적 형성 실험 및 해석)

  • Shin, Dong-Youn
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.26-29
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    • 2008
  • In the fields of electronics and displays where inkjet printing has demonstrated its capability to fabricate colorant subpixels of thin film transistor liquid crystal(TFT LCD) color filters and organic light emitting diode (OLED) displays, conducting tracks and TFTs, the production of satellite droplets is one of primary things to eliminate because they generally deteriorate the pattern quality. To understand the production mechanism of satellite droplets in this paper, driving waveforms such as monopolar and bipolar were employed and the influence of the pulse duration time were investigated in both experimental and numerical aspects.

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A Replica Molding Technique for Fabricating Liquid Crystal Displays with Wide Viewing Characteristics

  • Kim, Yeun-Tae;Hong, Jong-Ho;Choi, Yoon-Seuk;Lee, Sin-Doo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07a
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    • pp.371-373
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    • 2005
  • We demonstrated a replica molding technique for producing a self-formed multidomain structure displays (LCDs). The multidomain structure was naturally obtained on a replica mold film having periodic patterns which have two dimensional microgrooves. It was found that with the axially symmetric multidomain structure along the microgrooves exhibits excellent viewing characteristics.

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Requirements in terms of measurement area for viewing angle optical characterization of liquid crystal displays

  • Leroux, Thierry;Bignon, Thibault;Boher, Pierre
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07a
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    • pp.602-605
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    • 2005
  • In this paper, we present a model to calculate the influence of the measurement spot diameter MSD on the viewing angle measurements using a conoscopic instrument. This model is verified experimentally using an EZContrast instrument and the requirements for next generation of displays are presented. We show that last generation of EZContrast XL88W and L80W allowing measurement spot diameter up to 6mm can fulfill the requirements for all the FPD generations up to 80 inches diagonal.

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Optical Configurations for a Reflective LCD (반사형 LCD의 광학설계)

  • Yoon, Tae-Hoon;Lee, Gi-Dong;Kim, Jae-Chang
    • Proceedings of the Optical Society of Korea Conference
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    • 2001.02a
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    • pp.127-134
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    • 2001
  • With the increasing demands for hand-held devices with lightweight and low-power-consumption displays, the role of reflective liquid crystal displays (LCDs) is becoming more and more important. Especially, the single polarizer mode is considered as a suitable structure for reflective LCDs because it can provide high brightness. However, the single-polarizer LCDs have demerit in that the contrast is lower than double-polarizer LCDs because of the light leakage in thedark state. (omitted)

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Low temperature plasma deposition of microcrystalline silicon thin films for active matrix displays: opportunities and challenges

  • Cabarrocas, Pere Roca I;Abramov, Alexey;Pham, Nans;Djeridane, Yassine;Moustapha, Oumkelthoum;Bonnassieux, Yvan;Girotra, Kunal;Chen, Hong;Park, Seung-Kyu;Park, Kyong-Tae;Huh, Jong-Moo;Choi, Joon-Hoo;Kim, Chi-Woo;Lee, Jin-Seok;Souk, Jun-H.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.107-108
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    • 2008
  • The spectacular development of AMLCDs, been made possible by a-Si:H technology, still faces two major drawbacks due to the intrinsic structure of a-Si:H, namely a low mobility and most important a shift of the transfer characteristics of the TFTs when submitted to bias stress. This has lead to strong research in the crystallization of a-Si:H films by laser and furnace annealing to produce polycrystalline silicon TFTs. While these devices show improved mobility and stability, they suffer from uniformity over large areas and increased cost. In the last decade we have focused on microcrystalline silicon (${\mu}c$-Si:H) for bottom gate TFTs, which can hopefully meet all the requirements for mass production of large area AMOLED displays [1,2]. In this presentation we will focus on the transfer of a deposition process based on the use of $SiF_4$-Ar-$H_2$ mixtures from a small area research laboratory reactor into an industrial gen 1 AKT reactor. We will first discuss on the optimization of the process conditions leading to fully crystallized films without any amorphous incubation layer, suitable for bottom gate TFTS, as well as on the use of plasma diagnostics to increase the deposition rate up to 0.5 nm/s [3]. The use of silicon nanocrystals appears as an elegant way to circumvent the opposite requirements of a high deposition rate and a fully crystallized interface [4]. The optimized process conditions are transferred to large area substrates in an industrial environment, on which some process adjustment was required to reproduce the material properties achieved in the laboratory scale reactor. For optimized process conditions, the homogeneity of the optical and electronic properties of the ${\mu}c$-Si:H films deposited on $300{\times}400\;mm$ substrates was checked by a set of complementary techniques. Spectroscopic ellipsometry, Raman spectroscopy, dark conductivity, time resolved microwave conductivity and hydrogen evolution measurements allowed demonstrating an excellent homogeneity in the structure and transport properties of the films. On the basis of these results, optimized process conditions were applied to TFTs, for which both bottom gate and top gate structures were studied aiming to achieve characteristics suitable for driving AMOLED displays. Results on the homogeneity of the TFT characteristics over the large area substrates and stability will be presented, as well as their application as a backplane for an AMOLED display.

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Study on Liquid Crystal Displays Utilizing Kerr effect (액정의 Kerr 효과를 이용한 액정표시소자 연구)

  • Kim, Min-Su;Kang, Byeong-Gyun;Jung, Jun-Ho;Ha, Kyung-Su;Song, Eun-Gyoung;Yoon, Suk-In;Kim, Mi-Young;Lee, Myong-Hoon;Lee, Seung-Hee
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.06a
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    • pp.295-296
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    • 2009
  • There are various application of liquid crystal materials to devices, especially, blue phase liquid crystal (BPLC) and nano-structured liquid crystal mixture have been studied recently because BPs existing temperature range has been expanded by polymer-stabilization and liquid crystal has been confined in room which has certain coherence length so that their particular characters, such as fast response time and optically isotropic state at no electric field, could apply to advanced liquid crystal display devices. However, there is an crucial problem which is high operating voltage from low Kerr constant and limited electric field utilization using in-plain electric field. In this paper, we will analyze cell structure in the way of using electric field and show effective electric field utilization to reduce operating voltage.

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A Study on the Development and Commercialization Trends of Wearable Fashion Products Using Flexible Displays (플렉시블 디스플레이가 이용된 웨어러블 패션 제품 개발 및 상용화 동향에 관한 연구)

  • Lee, Hyewon
    • Journal of Fashion Business
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    • v.25 no.4
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    • pp.125-140
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    • 2021
  • Recently, flexible displays have been used as part of fashion beyond the concept of parts for electronic products. The flexible display applied to wearable fashion products flexibly bends according to the wearing position of the human body and, at the same time, decorates the fashion product more splendidly through the screen on which images or videos are displayed. Flexible displays, which are used for clothes and accessories, combine analogue fashion sensibility with digital screens to create a new level of convergence product design and expand the range of fashion design and fashion materials. This study aims to analyze the trends of the development and commercialization of fashion products that use flexible displays. As a research method, theoretical research and empirical research through case analysis were conducted in parallel. First, as a theoretical study, the morphological and technical characteristics of flexible displays were examined. Through theoretical studies, the effect of the characteristics of flexible displays on the development of wearable fashion products was investigated. Second, as an empirical case study, the design of wearable fashion products using flexible displays over the past 10 years and the characteristics of the displays used in the products were analyzed. Based on the characteristics analyzed, the product design, display and product integration methods and the commercialization stages of wearable fashion products using flexible displays were analyzed.

Colloidal Self-Assembly Route to Flexible Cholesteric LCDs and Other High-Efficiency Displays

  • Chari, Krishnan
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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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.

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