• Title/Summary/Keyword: liquid-crystal-display (LCD)

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Synthesis and Properties of Novel Homeotropic Alignment Materials with Long Side Chain

  • Han, B.R.;Kim, Y.B.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2002.08a
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    • pp.475-478
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    • 2002
  • VA-LCDs is widely used for recent LCD productions owing to good viewing angle and high contrast. To apply for VA-LCDs, we have synthesized novel homeotropic alignment materials, which all generated high pretilt angles ($9^{\circ}$). The thermal stabilities of them were observed by thermogravimetric analysis (TGA). Transmittances of the NLC cell used the new alignment material were not changed before and after thermal annealing at $120^{\circ}C$ for 24hrs. In this work, the synthesis and alignment properties of new homeotropic alignment materials will be reported.

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Wide-Viewing Liquid Crystal Displays with Periodic Surface Gratings

  • Lee, Sin-Doo;Park, Jae-Hong;Yoon, Tae-Young;Yu, Chang-Jae
    • 한국정보디스플레이학회:학술대회논문집
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    • 2002.08a
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    • pp.947-952
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    • 2002
  • A new concept of forming self-aligned multidomains is used for fabricating wide-viewing liquid crystal displays (LCDs) with periodic surface gratings.An array of the periodic surface gratings is produced on substrates using a photosensitive polymer by the illumination o. the UV light through a patterned photomask. A multidomain structure is naturally formed on the grating surface by the initial director distortions together with continuous variations of an external electric field. The LCD cells with periodic surface gratings are found to show excellent extinction in the off-state and wide-viewing property m the on-state.

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Voltage Application Indicator Using Liquid Crystal Device (LCD를 이용한 통전상태 표시기 개발)

  • Koo, K.W.;Lyu, S.H.;Han, S.O.
    • Proceedings of the KIEE Conference
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    • 2000.07c
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    • pp.1757-1759
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    • 2000
  • To make a inspection and maintenance of the high voltage equipment, electric machinery to transmit and distribute the electric power, the appearance of a simple and inexpensive indicator with which the charge condition of bare conductor parts could be read at a Stance has been needed. Liquid crystal has recently been expanding its application rapidly in appliances for everyday use. Since its display energy is extremely small, it is possible to obtain the working current with simple condenser voltage divider that makes use of stray capacity when it is applied to electric power equipment. Thus, an apparatus has finally appeared which is close to the one they have sought and indicates the existence of voltage impressions.

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Harmful Factors by Liquid Crystal Display Process and Research Trends on Non-Contact Liquid Crystal Alignment Methods (액정 디스플레이 공정별 유해요인 및 비접촉식 액정 배향 법 연구동향)

  • Kim, Dai Hyun
    • Proceedings of the Korean Society of Disaster Information Conference
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    • 2023.11a
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    • pp.215-216
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    • 2023
  • 본 논문에서는 액정 디스플레이 산업에서 발생하는 공정별 유해요인 및 연구동향에 대해 조사하였다. 액정 디스플레이는 컴퓨터, 텔레비전, 태블릿, 스마트폰 등에서 사용되는 주요 디스플레이 기술로, 빠른 응답속도와 저전력 운영, 높은 해상도 등을 제공한다. 액정 디스플레이 제조에서 중요한 역할을 하는 액정 배향 기술은 러빙 천을 사용하는 물리적 배향법과 같은 기존 방법의 단점을 극복하기 위해 비접촉식 액정 배향법과 같은 연구가 진행 중이다. 액정 디스플레이 제조과정은 TFT, 컬러필터, 액정, 모듈 단계로 이루어져 있으며 이 과정에서 사용되는 다양한 화학물질은 작업자에게 노출 될 수 있다. 그러므로 유해요인의 관리와 분석, 공정의 개선, 그리고 화학 물질 사용 최소화와 같은 기술에 대한 연구가 중요하다. 최근에는 비접촉식 액정 배향법 및 박막 제작 기술에 대한 연구가 활발히 진행 중이며, 소자 오염 및 배향 공정 등에서 발생하는 유해요인을 최소화하기 위한 노력이 계속되고 있다.

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A New Approach to Estimating Product Lifetimes: A Case Study of an LED Based LCD TV

  • Kim, Keun-Hwan;Kim, Chi-Hwan;Park, Hyun-Woo
    • Asian Journal of Innovation and Policy
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    • v.1 no.2
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    • pp.200-218
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    • 2012
  • Estimating the economic life of a technology is the first important prerequisite step in the feasibility analysis of technology-based business. Many empirical studies have concentrated on patents data to estimate the time period for a technology. However, it is recommended to estimate it along with qualitative considerations of future technological and market conditions. In this regard, little is known about how approaches are applied. This paper aims to establish a structural framework of estimating the lifetime of a technology by integrating the outputs of an analysis of the determinants in each transition of a product life cycle. We describe an illustrative case about a light emitting diode (LED) backlight unit (BLU) technology for the liquid crystal display (LCD) TV. The framework allows valuators and experts to estimate a technology lifetime by using multidimensional factors.

Two Approaches in LCDs With Fast Electro-optic Response: PSV-mode FLCDs and FM-TN-LCDs

  • Kobayashi, Shunsuke
    • 한국정보디스플레이학회:학술대회논문집
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    • 2004.08a
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    • pp.911-914
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    • 2004
  • This paper discusses on new two LCD technologies featured by the fast electro-optic response:one is polymer-stabilized FLCDs that exhibit V-shaped electro-optic (EO) switching called PSV-mode FLCDs with response time of 400 ${\mu}$ s; and the other is TN-mode LCDs that exhibit a frequency modulation response (called PM-TN LCDs)and a peculiar sensitivity to the high frequency component of driving voltage waveforms resulting in a short decay time constant of 5ms and an enhancement in the over-driving that yields short response time of 1ms between two gray levels.

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The Optimization of LCD Color Filter Coating Method

  • Cho, Moon-Chul;Bae, Dong-Ho
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.11a
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    • pp.177-177
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    • 2009
  • We examine the process to enhance the productivity of the thin-film transistor-addressed liquid-crystal display (TFT LCD) panels with the objective of optimizing the relation between the Type of color PR dispense nozzle and the amount of dispensing of color PR consumption, directly affecting a spectroscopic analysis. Most manufacturers of the panels have been utilizing a spin-type coater. We show that we successfully optimize the spectral values by controlling the color PR dispense type(Static dispense or Dynamic dispense) and the amount of color PR. From this study, we accomplished to decrease 43% in color PR consumption and to decrease 30% in color PR Stained, to decrease 30% rework rate.

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Multivariate Gamma-Poisson Model and Parameter Estimation for Polytomous Data : Application to Defective Pixels of LCD (다가자료에 적합한 다변수 감마-포아송 모델과 파라미터 추정방법 : LCD 화소불량 응용)

  • Ha, Jung-Hoon
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.34 no.1
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    • pp.42-51
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    • 2011
  • Poisson model and Gamma-Poisson model are popularly used to analyze statistical behavior from defective data. The methods are based on binary criteria, that is, good or failure. However, manufacturing industries prefer polytomous criteria for classifying manufactured products due to flexibility of marketing. In this paper, I introduce two multivariate Gamma-Poisson(MGP) models and estimation methods of the parameters in the models, which are able to handle polytomous data. The models and estimators are verified on defective pixels of LCD manufacturing. Experimental results show that both the independent MGP model and the multinomial MGP model have excellent performance in terms of mean absolute deviation and the choice of method depends on the purpose of use.

Design of a Large Magnetron Sputtering System for TFT LCD and Investigation of Sputtered AI Film Properties (TFT LCD 제조용 대면적 Magnetron Sputtering 장치 설계와 Al 성장막 특성 조사)

  • 유운종
    • Journal of the Korean Vacuum Society
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    • v.2 no.4
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    • pp.480-485
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    • 1993
  • Factros considered building the magnetron sputtering system for TFT LCD (thin film transistor liquid crystal display0 metallization were thin film thichnes uniformity, temperature uniformity and the pressure gradient of sputtering gas flow in vacuum chamber, base pressure, and the stability fo the carrier moving . The system was consisted of a deposition chamber, a pre-heating chamber, a RF-precleaning chamber and a load/unload lock chamber. The system was designed to handle a substrate with dimension of 400$\times$400mm. The temperautre uniformity of a heater table developed showed $250 ^{\circ}C\pm$5% accuracyon the substrate glass. A base pressure of 1.8 $\times$10-7 torr was obtained after 24 hours pumping with a cryo pump. After an aluminum target was installed in a sputtering source and the film wa sdeposited on the glass, the uniformity, reflectivity and sheet resistance of the deposited film were measured.

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Ambient Light Backscatter Communication for IoT Applications

  • Yun, Jisu;Jang, Byung-Jun
    • Journal of electromagnetic engineering and science
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    • v.16 no.4
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    • pp.214-218
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    • 2016
  • In this paper, we present an ambient light backscatter communication design that enables Internet of Things (IoT) devices to communicate through the backscattering ambient light emitted from lighting infrastructure or sunlight. The device can selectively modulate ambient light by switching a liquid crystal display (LCD) shutter located on its surface, so that a nearby smart device, which includes a photodiode or a camera, can demodulate this backscattered light information. To verify the practicality of the proposed concept, we design an IoT device equipped with a commercial LCD shutter and a microcontroller. Our device produces ambient light backscattered data at a speed of 100 bps, and these data are successfully decoded by a commercial photodiode module 10 cm away from the IoT device. We believe that our ambient light backscatter communication design is appropriate for implementation in various IoT applications.