• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.1
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• pp.98-106
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• 2009

This work proposes a 1280-RGB $\times$ 800-Dot 70.78mW 0.l3um CMOS LCD driver IC (LDI) for high-performance 16M-color low temperature poly silicon (LTPS) thin film transistor liquid crystal display (TFT-LCD) systems such as ultra mobile PC (UMPC) and mobile applications simultaneously requiring high resolution, low power, and small size at high speed. The proposed LDI optimizes power consumption and chip area at high resolution based on a resistor-string based architecture. The single column driver employing a 1:12 MUX architecture drives 12 channels simultaneously to minimize chip area. The implemented class-AB amplifier achieves a rail-to-rail operation with high gain and low power while minimizing the effect of offset and output deviations for high definition. The supply- and temperature-insensitive current reference is implemented on chip with a small number of MOS transistors. A slew enhancement technique applicable to next-generation source drivers, not implemented on this prototype chip, is proposed to reduce power consumption further. The prototype LDI implemented in a 0.13um CMOS technology demonstrates a measured settling time of source driver amplifiers within 1.016us and 1.072us during high-to-low and low-to-high transitions, respectively. The output voltage of source drivers shows a maximum deviation of 11mV. The LDI with an active die area of $12,203um{\times}1500um$ consumes 70.78mW at 1.5V/5.5V.

• Journal of the Korean Society for Nondestructive Testing
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• v.22 no.4
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• pp.347-353
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• 2002

A structure of a glass electrode-type pH sensor for measuring any concentration of $H^+$ in an aqueous solution was embodied with bulk micromachining technology. Two open well structures were formed, and a reference electrode was secured by the Ag/AgCl thin film in the sloped side of the etched structure. A sensitive membrane of an indicator electrode for generating a potential by an exchange reaction to $H^+$ was made with a glass containing Na 20% or more finely so that its thickness might be $100{\mu}m$ or so, and then it was bonded to one pyramidal structure. A liquid junction for a current path was formed by filling an agar in the anisotropically etched part of the Si wafer, which had a size of $50{\mu}m{\times}50{\mu}m$, and then bonded it to the other. After complete fabrication of each part, it was filled with a 2M KCl reference solution and encapsulated the sensor structure with a cold expoxy. The potential value of fabricated pH sensor was about 90mV/pH in the standard pH solutions.

• Transactions on Electrical and Electronic Materials
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• v.8 no.3
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• pp.135-138
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• 2007

In this study, we investigated the electro-optical (EO) characteristic of fringe-field switching (FFS) mode cell by the two kinds of ultraviolet (UV) alignment method on the organic thin film (polyimide: PI). The suitable organic layers for FFS cell and the aligning capabilities of nematic liquid crystal (NLC) using the in-situ photoalignment method were studied; Disclination is observed after conventional photoalignment method for 1h, and in-situ photoalignment method for 1h. Monodomain alignment of the NLC can be observed via insitu photo alignment method for 2 h and 3 h. It is considered that NLC alignment is due to photo-depolymerization of the polymer with oblique non-polarized UV irradiation on PI surface. An unstable V-T curve of UV-aligned FFS-LCD with conventional photoalignment method can be achieved. However, a stable V-T curve of UV-aligned FFS-LCD with in-situ photoalignment method (1 h), and V-T curve of UV-aligned FFS-LCD with in-situ photo alignment method was much stable comparing with that of other UV-aligned FFSLCD's. As a result, more stable EO performance of UV-aligned FFS-LCD with in-situ photoalignment method for 3h is obtained than that of the other UV-aligned FFS-LCD's.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.492-498
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• 2021

This feasibility study evaluated an optically transparent planar antenna using liquid salt-water as the conducting material. The most significant reason behind using liquid salt-water for transparent antenna applications is its excellent average optical transparency (OTav) (> 95% at a salinity of 40 ppt) compared to other typical solid transparent thin-film electrodes, such as indium tin oxide (ITO:> 73%) or multi-layer films (MLF: > 78%). Each conductive arm of the proposed dipole is constructed from a salt-water layer held between two clear planar acrylic layers (��r = 2.61, tan�� = 0.01, OTav > 90%) (acrylic/salt-water/acrylic; ASA) due to surface tension. To examine the electrical and optical properties of the ASA structure, the surface tension was measured to determine the thickness of the salt-water layer that finalized its sheet resistance and OTav. The average gain and efficiency of the antenna were 1.72 dBi and 74%, respectively, in the operating UHF (Ultra high frequency) band (470-771 MHz). Therefore, the proposed antenna can be a good candidate for applications as a transparent planar antenna using salt-water.

• Korean Journal of Optics and Photonics
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• v.28 no.1
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• pp.9-15
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• 2017

We precisely measured and analyzed the dynamics of peptide-antibody interactions, using an ellipsometric biosensor based on a silicon substrate. To reduce the signal error due to the imperfect flatness of the substrate for extremely low concentrations of peptide, we fabricated the biosensor with a silicon substrate coated with Dextran SAM, instead of a glass prism coated with a thin metallic thin film. At an injection speed of $100{\mu}l/min$ of buffer liquid, we detected the dynamics of antibody-Dextran SAM or peptide-antibody fixed on biosensor, respectively. We detected the dynamics of antibody-Dextran SAM interactions down to a low concentration of 5 ng per liter, and we precisely measured the dynamics of association and dissociation of peptide and antibody down to 100 nM of peptide. We obtained the rate constants for association and dissociation from fitting the data by using deduced dynamical equation. As a result, we obtained an equilibrium constant for dissociation of 97 nM of peptide-antibody complex, which belongs to Class I.

• The Magazine of the IEIE
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• v.29 no.6
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• pp.76-80
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• 2002

'Liquid Crystal의 상전이(相轉移)와 광학적 이방성(異方性)이 1888년과 1889년 F. Reinitzer와 O. Lehmann에 의해 Monatsch Chem.과 Z.Physikal.Chem.에 각각 보고된 후 부터 제2차 세계대전이 끝난 뒤인 1950년대 까지는 Liquid Crystal을 단지실험실에서의 기초학문 차원의 연구 대상으로만 다루어 왔다. 1963년 Williams가 Liquid Crystal Device로는 최초로 특허 출원을 하였으며, 1968년 RCA사의 Heilmeier등은 Nematic 액정(液晶)에 저주파(低周波) 전압(電壓)을 인가하면 투명한 액정이 혼탁(混濁)상태로 변화하는 '동적산란(動的散亂)'(Dynamic Scattering) 현상을 이용하여 최초의 DSM(Dynamic Scattering Mode) LCD(Liquid Crystal Display)를 발명하였다. 비록 150V 이상의 높은 구동전압과 과소비전력의 특성 때문에 실용화에는 실패하였지만 Guest-Host효과와 Memory효과 등을 발견하였다. 1970년대에 이르러 실온에서 안정되게 사용 가능한 액정물질들이 합성되고(H. Kelker에 의해 MBBA, G. Gray에 의한 Cyano-Biphenyl 액정의 합성), CMOS 트랜지스터의 발명, 투명도전막(ITO), 수은전지등의 주변기술들의 발전으로 인하여 LCD의 상품화가 본격적으로 이루어지게 되었다. 1971년에는 M. Shadt, W. Helfrich, J.L. Fergason등이 TN(Twisted Nematic) LCD를 발명하여 전자 계산기와 손목시계에 응용되었고, 1970년대 말에는 Sharp에서 Dot Matrix형의 휴대형 컴퓨터를 발매하였다. 이러한 단순 구동형의 TN LCD는 그래픽 정보를 표시하는 데에는 품질의 한계가 있어 1979년 영국의 Le Comber에 의해 a-Si TFT(amorphous Silicon Thin Film Transistor) LCD의 연구가 시작되었고, 1983년 T.J. Scheffer, J. Nehring, G. Waters에 의해 STN(Super Twisted Nematic) LCD가 창안되었고, 1980년 N. Clark, S. Lagerwall 및 1983년 K.Yossino에 의해 Ferroelectric LCD가 등장하여 LCD의 정보 표시량 증대에 크게 기여하였다. Color화의 진전은 1972년 A.G. Ficher의 셀 외부에 RGB(Red, Green, Blue) filter를 부착하는 방안과, 1981년 T. Uchida 등에 의한 셀 내부에 RGB filter를 부착하는 방법에 의해 상품화가 되었다. 1985년에는 J.L. Fergason에 의해 Polymer Dispersed LCD가 발명되었고, 1980년대 중반에 이르러 동화상(動畵像) 표시가 가능한 a-Si TFT LCD의 시제품(試製品) 개발이 이루어지고 1990년부터는 본격적인 양산 시대에 접어들게 되었다. 1990년대 초에는 STN LCD의 Color화 및 대형화(大型化) 고(高)품위화에 힘입어 Note-Book PC에 LCD가 본격적으로 적용이 되었고, 1990년대 후반에는TFT LCD의 표시품질 대비 가격경쟁력 확보로 인하여 Note-Book PC 시장을 독점하기에 이르렀다. 이후로는 TFT LCD의 대형화가 중요한 쟁점으로 부각되고 있고, 1995년 삼성전자는 당시 세계최대 크기의 22' TFT LCD를 개발하였다. 또한 LCD의 고정세(高情細)화를 위해 Poly Si TFT LCD의 개발이 이루어졌고, 디지타이져 일체형 LCD의 상품화가 그 응용의 폭을 넓혔으며, LCD의 대형화를 위해 1994년 Canon에 의해 14.8', 21' 등의 FLCD가 개발되었다. 대형화 방안으로 Tiled LCD 기술이 개발되고 있으며, 1995년에 Sharp에 의해 21' 두장의 Panel을 이어 붙인 28' TFT LCD가 전시되었고 1996년에는 21' 4장의 Panel을 이어 붙인 40'급 까지의 개발이 시도 되었으며 현재는 LCD의 특성향상과 생산설비의 성능개선과 안정적인 공정관리기술을 바탕으로 삼성전자에서 단패널 40' TFT LCD가 최근에 개발되었다. Projection용 디스플레이로는 Poly-Si TFT LCD를 이용하여 $25'{\sim}100'$사이의 배면투사형과 전면투사형 까지 개발되어 대형 TV시장을 주도하고 있다. 21세기 디지털방송 시대를 맞아 플라즈마디스플레이패널(PDP) TV, 액정표시장치 (LCD)TV, 강유전성액정(FLCD) TV 등 2005년에 약 1500만대 규모의 거대 시장을 형성할 것으로 예상되는 이른바 '벽걸이TV'로 불리는 차세대 초박형 TV 시장을 선점하기 위하여 세계 가전업계들이 양산에 총력을 기울이고 있다. 벽걸이TV 시장이 본격적으로 형성되더라도 PDP TV와 LCD TV가 직접적으로 시장에서 경쟁을 벌이는 일은 별로 없을 것으로 보인다. 향후 디지털TV 시장이 본격적으로 열리면 40인치 이하의 중대형 시장은 LCD TV가 주도하고 40인치 이상 대화면 시장은 PDP TV가 주도할 것으로 보는 시각이 지배적이기 때문이다. 그러나 이러한 직시형 중대형(重大型)디스플레이는 그 가격이 너무 높아서 현재의 브라운관 TV를 대체(代替)하기에는 시일이 많이 소요될 것으로 추정되고 있다. 그 대안(代案)으로는 비교적 저가격(低價格)이면서도 고품질의 디지털 화상구현이 가능한 고해상도 프로젝션 TV가 유력시되고 있다. 이러한 고해상도 프로젝션 TV용으로 DMD(Digital Micro-mirror Display), Poly-Si TFT LCD와 LCOS(Liquid Crystals on Silicon) 등의 상품화가 진행되고 있다. 인터넷과 정보통신 기술의 발달로 휴대형 디스플레이의 시장이 예상 외로 급성장하고 있으며, 요구되는 디스플레이의 품질도 단순한 문자표시에서 그치지 않고 고해상도의 그래픽 동화상 표시와 칼라 표시 및 3차원 화상표시까지 점차로 그 영역이 넓어지고 있다. <표 1>에서 보여주는 바와 같이 LCD의 시장규모는 적용분야 별로 지속적인 성장이 예상되며, 새로운 응용분야의 시장도 성장성을 어느 정도 예측할 수 있다. 따라서 LCD기술의 연구개발 방향은 크게 두가지로 분류할 수 있으며 첫째로는, 현재 양산되고 있는 LCD 상품의 경쟁력강화를 위하여 원가(原價) 절감(節減)과 표시품질을 향상시키는 것이며 둘째로는, 새로운 타입의 LCD를 개발하여 기존 상품을 대체하거나 새로운 시장을 창출하는 분야로 나눌 수 있다. 이와 같은 관점에서 현재 진행되고 있는 LCD기술개발은 다음과 같이 분류할 수 있다. 1) 원가 절감 2) 특성 향상 3) New Type LCD 개발.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.spc
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• pp.30-36
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• 2022

A sensor is needed to continuously and automatically measure the change in HNS concentration in industrial facilities that directly discharge to the sea after water treatment. The basic function of the sensor is to be able to detect ppb levels even at room temperature. Therefore, a method for increasing the sensitivity of the existing sensor is proposed. First, a method for increasing the conductivity of a film using a conductive carbon-based additive in a nanoparticle thin film and a method for increasing ion adsorption on the surface using a catalyst metal were studied.. To improve conductivity, carbon black was selected as an additive in the film using ITO nanoparticles, and the performance change of the sensor according to the content of the additive was observed. As a result, the change in resistance and response time due to the increase in conductivity at a CB content of 5 wt% could be observed, and notably, the lower limit of detection was lowered to about 250 ppb in an experiment with organic solvents. In addition, to increase the degree of ion adsorption in the liquid, an experiment was conducted using a sample in which a surface catalyst layer was formed by sputtering Au. Notably, the response of the sensor increased by more than 20% and the average lower limit of detection was lowered to 61 ppm. This result confirmed that the chemical resistance sensor using metal oxide nanoparticles could detect HNS of several tens of ppb even at room temperature.

• Resources Recycling
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• v.24 no.1
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• pp.58-65
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• 2015

Although Korea is a top market sharing and world leading producer and developer of flat panel display devices, relevant recycling technology is not up to her prestigious status. Besides, most of the waste glass arising from flat panel displays is currently land-filled. The present paper mainly reviews on development of recycling systems for waste TFT-LCD glass from end-of-life LCD TVs and monitors and TFT-LCD process waste of crushed glass particles with target end uses of raw material for high strength concrete pile and glass fibers, respectively. Waste LCD glass was recycled to fabricate ingredients for high strength concrete piles with enhanced physical properties and spherical foam products. The waste LCD glass recycling technology is already developed to fabricate long and short fibers at commercial level. In view of these, future R & D on waste LCD glass materials is to be directed toward implementation of commercial materials recycling system therefrom.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1261-1262
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• 2008

Laser-based crystallization techniques are ideally-suited for forming high-quality crystalline Si films on active-matrix display backplanes, because the highly-localized energy deposition allows for transformation of the as-deposited a-Si without damaging high-temperature-intolerant glass and plastic substrates. However, certain significant and non-trivial attributes must be satisfied for a particular method and implementation to be considered manufacturing-worthy. The crystallization process step must yield a Si microstructure that permits fabrication of thin-film transistors with sufficient uniformity and performance for the intended application and, the realization and implementation of the method must meet specific requirements of viability, robustness and economy in order to be accepted in mass production environments. In recent years, Low Temperature Polycrystalline Silicon (LTPS) has demonstrated its advantages through successful implementation in the application spaces that include highly-integrated active-matrix liquid-crystal displays (AMLCDs), cost competitive AMLCDs, and most recently, active-matrix organic light-emitting diode displays (AMOLEDs). In the mobile display market segment, LTPS continues to gain market share, as consumers demand mobile devices with higher display performance, longer battery life and reduced form factor. LTPS-based mobile displays have clearly demonstrated significant advantages in this regard. While the benefits of LTPS for mobile phones are well recognized, other mobile electronic applications such as portable multimedia players, tablet computers, ultra-mobile personal computers and notebook computers also stand to benefit from the performance and potential cost advantages offered by LTPS. Recently, significant efforts have been made to enable robust and cost-effective LTPS backplane manufacturing for AMOLED displays. The majority of the technical focus has been placed on ensuring the formation of extremely uniform poly-Si films. Although current commercially available AMOLED displays are aimed primarily at mobile applications, it is expected that continued development of the technology will soon lead to larger display sizes. Since LTPS backplanes are essentially required for AMOLED displays, LTPS manufacturing technology must be ready to scale the high degree of uniformity beyond the small and medium displays sizes. It is imperative for the manufacturers of LTPS crystallization equipment to ensure that the widespread adoption of the technology is not hindered by limitations of performance, uniformity or display size. In our presentation, we plan to present the state of the art in light sources and beam delivery systems used in high-volume manufacturing laser crystallization equipment. We will show that excimer-laser-based crystallization technologies are currently meeting the stringent requirements of AMOLED display fabrication, and are well positioned to meet the future demands for manufacturing these displays as well.

• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.5
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• pp.711-720
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• 2009

Leaf fibers have many good properties; they are strong, long, cheap, abundant and bio-degradable. Since they, however, contain a great quantity of non-cellulose components, they have been used for the materials of mats, ropes, bags and nets rather than those of clothing. In this study, we investigated the characteristics of leaf fibers in order to promote the use of leaf fibers for the materials of clothing as well as develop the high value-added textile fibers. Leaf fiber plants including New Zealand Flax, Henequen and Banana plant, which have various nature and shape, were used. New Zealand Flax and Henequen leaves were cut from lower part of plants. Banana leaves and pseudo-stems were peeled and cut from the stem of Banana plants. First, the thin outer skins like film of leaves, veins and stems were removed before retting. The chemical retting had been processed for 1hour, at 100 in 0.4% $H_2SO_4$ aqueous solution(liquid ratio 50:1). Then, the retted leaf fibers had been soaked for 1hour, at room temperature in 0.5% NaClO solution(v/v) to remove the miscellaneous materials. We investigated the physical characteristics of three leaf fibers including the transversal and longitudinal morphology, the contents(%) of pectin, lignin and hemicellulose, the length and diameter of fibers, the tensile strength of the fiber bundles, and the fiber crystallinity and the moisture regain(%). The lengths of fiber from three leaf fibers were similar to their leaf lengths. The fiber bundles were composed of the cellulose paralleled to the fiber axis and the non-cellulose intersecting at right angle with the fiber axis. The diameters of New Zealand Flax, Henequen and Banana fibers were $25.13{\mu}m$, $18.16{\mu}m$ and $14.01{\mu}m$, respectively and their tensile strengths were 19.40 Mpa, 32.16 Mpa and 8.45 Mpa, respective. The non-cellulose contents of three leaf fibers were relatively as high as 40%. If the non-cellulose contents of leaf fibers might be controlled, leaf fibers could be used for the materials of textile fiber, non-wovens and Korean traditional paper, Hanjee.