• 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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• 제33권2호
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• pp.123-129
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• 2020

We analyzed the drift current by charged particles according to the loading methods applied into a closed cell by electronic ink at a reflective-type display panel using an electrophoretic mechanism. For this experiment, various panels were fabricated with injection voltages for electronic ink taking values in the range -4~0 V. The size of each cell was 220 ㎛ × 220 ㎛ and height of the barrier rib was 54.28 ㎛. The electronic ink was fabricated by mixing electrically neutral fluid and single-charge white particles. Drift current was measured by moving charged particles. A biasing voltage of 6 V was applied to the display panel. As a result, the drift current was proportional to the injection voltage for electronic ink, but it decreased in case of an injection voltage above -3 V. Our experimentation ascertained that the concentration of charged particles injected into closed cells is controlled by the injection voltage and the selective injection of charged particles above movable q/m is possible.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2000년도 제1회 학술대회 논문집
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• pp.145-146
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• 2000

Primary emphasis was placed on the electrophoretic deposition of low voltage phosphor to indium-tin oxide-coated glass for the application of field emission display. The phosphor deposited by various parameters, such as deposition time and applied voltages was examined in detail. In addition, a comparison was made by analyzing luminance properties of the phosphor mixed with and without conducting $In_2O_3$ powder of less than 1um size. The measurement was performed as a function of $In_2O_3$ concentration from 3% to 15% by weight. The enhanced impact of indium powder mixing on the phosphor was clearly demonstrated by aging performance curve at 1000V excitation voltages with a current density of $1\;mA/cm^2$

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.421-427
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• 2009

We successfully fabricated 4.7-inch organic thin film transistors array with $640{\times}480$ pixels on flexible substrate. All the processes were done by photolithography, spin coating and ink-jet printing. The OTFT-Electrophoretic (EP) pixel structure, based on a top gate OTFT, was fabricated. The mobility, ON/OFF ratio, subthreshold swing and threshold voltage of OTFT on flexible substrate are: 0.01 ^2/V-s, 1.3 V/dec, 10E5 and -3.5 V. After laminated the EP media on OTFT array, a panel of 4.7-inch $640{\times}480$ OTFT-EPD was fabricated. All of process temperature in OTFT-EPD is lower than $150^{\circ}C$. The pixel size in our panel is $150{\mu}m{\times}150{\mu}m$, and the aperture ratio is 50 %. The OTFT channel length and width is 20 um and 200um, respectively. We also used OTFT to drive EP media successfully. The operation voltages that are used on the gate bias are -30 V during the row data selection and the gate bias are 0 V during the row data hold time. The data voltages that are used on the source bias are -20 V, 0 V, and 20 V during display media operation.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.274-277
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• 2006

Nanostructured carbon (nm-C), including carbon nanotubes and nanofibers (CNTs/CNFs) is promising for low-cost field emission display (FED) application. By modification of CNTs/CNFs, uniform CNTs/CNFs can be obtained and used for field emission cathode (FEC) on glass substrate. By screen-printing (SP) and electrophoretic deposition (EPD) process, large area FEC can be obtained. The FED properties are studied and compared. Both SP and EPD FEC show excellent field emission properties, such as low emission field and uniform emission, after optimization the fabrication process. While EPD FEC exhibits better luminescence image. By vacuum sealing, the low cost nm-C-FED prototypes based on EPD cathode have been demonstrated.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.441-445
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• 2007

In this paper we demonstrated the applications of OTFTs (organic thin film transistors) to flexible displays such as AM-EPD (active matrix electrophoretic display) and AM-OLED (active matrix organic light emitting diode), and also to integrated circuits. The OTFTs using pentacene semiconductor layer and PVP gate dielectric and Au S/D electrodes exhibited good performance for AM-EPD with the mobility of $0.59\;cm^{2}/V.sec,$ and with also good uniformity over 2.5" diagonal area. However, it is nor enough for AM-OLED requiring the mobility larger than $1\;cm^{2}/V.sec$ for large area displays. The integrated circuits also worked, producing the operating frequency of 1MHz. We need to develop a fabrication process to reduce parasitic capacitance for high frequency operation.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.998-1000
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• 2003

We have investigated thin film morphology of pentacene thin films by the process of low-pressure gas assisted organic vapor deposition (LP-GAOVD). Source temperature, inert gas flow rate, substrate temperature and deposition pressure during film deposition is used to vary the growth rate, thin film morphology and the crystalline grain size of pentacene thin films. The electrical properties of pentacene thin films for applications in organic thin film transistor and electrophoretic displays will be discussed.

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2011년도 제44차 학술발표회
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• pp.71-71
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• 2011

전류를 흘렸을 때 양극과 음극에 따라 움직이는 미세한 나노입자를 이용하여 색, 글자, 그림 등을 표시하는 응용디스플레이 기술이 전기영동디스플레이(electrophoretic display)이다. 최근 전자종이 등 상품화가 진행되면서 전기영동디스플레이에 대한 관심증대와 함께 기술개발이 지속적으로 진행되고 있다. 본 연구에서는 분산중합을 이용하여 $TiO_2$ core 입자에 polystyrene을 shell로 코팅하여 마이크로캡슐형의 전기영동디스플레이에 적합한 입자를 제조하고 성능을 분석하였다. 먼저 분산제의 종류, 모노머의 농도, 개시제의 농도에 따라 제조된 대전복합입자의 크기 및 분포를 보면, 분산제의 종류를 달리 하였을때를 제외하고 대체로 균일하였다. 입경의 변화를 보면, 약 200-300nm의 $TiO_2$가 개질에 의해 400-500nm의 입경을 나타내는 것으로부터 200nm 두께의 shell층을 갖는다는 것을 확인 할 수 있었다. 또한 분산제의 종류에 따라서는 분산제를 사용하지 않는 경우가 오히려 제조된 입자의 분포가 균일함을 알 수 있었고 모노머의 농도에 따른 변화는 볼 수 없었으며 입경분포가 균일한 입자가 제조되었음을 알 수 있었다. 대전복합입자의 TGA 곡선으로부터 $300^{\circ}C$ 부근에서 polystrene shell에 의한 분해를 볼 수 있었고 $600^{\circ}C$ 이후에 잔류된 core의 $TiO_2$ 입자를 확인 할 수 있었다. 이 결과로부터 $TiO_2$ core-polystyrene shell형의 전자 종이용 대전복합입자의 제조를 확인 할 수 있었다. 또한 제조된 대전복합입자의 zeta potential을 보면, (+)전하를 띄며 64.8mV의 비교적 높은 zeta potential을 가지는 것을 확인 할 수 있었다. 그리고 $TiO_2$ 대전복합입자와 같은 방법으로 제조된 흑색 대전복합입자를 혼합하여 cell test를 측정한 결과, cell에 ${\pm}$10V의 저전압을 가했을 때에도 비교적 응답속도가 빠른 입자의 구동현상을 확인 할 수 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.341-342
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• 2008

The dynamics of nano particles in LC medium under an external electric field is of theoretical and technological interest. In this work, the dynamical characteristics of fullerene $(C_{60})$ particles in liquid crystal (LC) medium under dc electric field have been investigated. This effect was studied for homogeneously aligned nematic LC cells driven by in-plane field. The $C_{60}$ was found to be aggregated in a form of cluster inside the LC medium. Hence polystytene was used to protect the aggregation of $C_{60}$ in LC medium. When the electric field was applied, the fullerenes start to move in direction of applied electric field. The density of $C_{60}$'s particles at the electrodes increase with increase in the value of applied electric field. The dynamical motions of fullerene $(C_{60})$ particles in liquid crystal (LC) suggest that fullerene can be designed for electrophoretic displays (i.e., electronic ink).

• 한국미생물·생명공학회지
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• 제37권4호
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• pp.355-360
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• 2009

P. carageenovora 유래 arylsulfatase 유전자(astA)의 효모표면발현 plasmid pCTAST(7.1 kb)를 구축하여 S. cerevisiae EBY100에 형질전환하였고, 선별된 형질전환체들을 YPDG 배지에서 배양했을 때 4-methylumbelliferyl sulfate를 분해하여 형광을 보였다. 이는 효모에서 arylsulfatase가 활성형으로 생산되었음을 의미하였다. S. cerevisiae EBY100/pCTAST를 플라스크 배양했을 때 arylsulfatase 활성은 galactose가 완전히 소모된 배양 48시간째 최대 활성인 1.2 unit/mL로 나타났으며 배양 상등액에서는 활성이 나타나지 않았다. 효모 S. cerevisiae의 세포표면에서 발현된 재조합 arylsulfatase로 제조된 agarose를 agar와 시판용 agarose와 함께 ${\lambda}DNA$ HindIII marker를 사용하여 DNA 전기영동 성능을 비교 실험한 결과, agar보다는 재조합 arylsulfatase 처리로 제조한 agarose가 이동성이나 분리능에서 우수하였으며, 시판용 agarose와 비교하여 이동성이나 분리능이 유사한 결과를 확인할 수 있었다. 본 연구의 결과, 효모 S. cerevisiae의 세포표면에서 발현된 재조합 arylsulfatase 효소를 이용하여 한천으로부터 전기영동용 고순도 친환경적인 agarose 생물 생산 공정에 적용 가능함을 알 수 있었다.