• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1216-1219
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• 2007

We have been developing printed organic TFTs for flexible displays. In this study, we have pay attention to the operation stability improvement of the organic TFTs, and studied several factors especially depending on the dielectric layers. From the detailed analysis of the effects of dielectric layers, we have proposed a new printed dielectric layer which is mainly consisting of metal oxide and gives high operation stability

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1336-1339
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• 2007

Since organic thin film transistor (OTFT) provides simple and low cost processes, its application to the OTFT display has been studied. We developed an RC oscillator using organic thin film transistor and inverters with bootstrapping transistors. Device parameters were optimized by the simulation and OTFT RC oscillators were fabricated. The oscillator frequency and its dependence on resistance and bias voltage were studied. The organic TFT is adequate for low cost and simple process integrated circuits. The frequency of oscillation was simulated and measured. It is acceptable for low-cost microelectronic device and flat panel displays.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.238.2-238.2
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• 2011

Organic thin film transistors (OTFTs) have been attracting considerable attention because of their potential use in low-cost, large area, electronic devices such as flexible displays, biochemical sensors, and smart cards. In past several years, gold/pentacene has been frequently used in OTFTs because of the high mobility of pentacene and the high work function of gold. To improve the performance of the OTFTs contact area doping of pentacene with p-doping materials are well known. In this work we demonstrated selectively contact area doping of pentacene with Iodine vapor. For effective doping elevated pentacene layer under the source-drain area was deposited and exposed to Iodine vapor. We got better electrical performance for elevated pentacene structure rather than planer structure with relatively high field-effect mobility.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1111-1114
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• 2006

We have developed a 2 inch LTPS-TFT AMOLED display with a top emission structure on a $50-{\mu}m-thick$ metal foil. The Active matrix back planes were fabricated with the p-channel LTPS TFT with a conventional pixel circuit consisting of 2 transistors and 1 capacitance. The p-channel TFTs on the metal foil exhibited the field-effect mobility of $22cm^2/Vs$. Finally, a images from prototype monochrome AMOLED displays are successfully presented, with $64{\times}88$ pixels and 56-ppi resolution.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.892-896
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• 2005

In this paper, key issues of stainless steel foil substrates for display applications have been described. We studied and analyzed technical issues on substrate passivation/planarization to control surface roughness and capacitive coupling from conductive substrates. A thick (either multiple or single) passivation/planarization layer needs to be applied on the nonelectronic-grade stainless steel substrate to provide a smooth surface and electrical insulation from the conductive substrate. Especially for large size, high-resolution display applications, low k and thick passivation/planarization layers should be used for appropriate capacitive coupling. Based on our initial study, a unit area capacitance of less than $2nF/cm^2$ of passivation/planarization layers is needed for 32" HD TV OLED displays.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.1053-1056
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• 2003

Progress in light emitting materials is presented. New polymers based on the Spiro concept show encouraging properties in electroluminescence performance and lifetime. The spiro-polymers can be tailor made to fit the RGB color requirements of a full color display. This class of materials showed recently very promising performance for white emission as well. They are readily soluble, show excellent thermal stability and can be processed by printing or through simple synthetic modification by photolithography technology.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.4
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• pp.282-285
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• 2012

It is well known that Zinc Oxide (ZnO) is an attractive material for its various applications. ZnO has been mostly used as a transparent conducting oxide in liquid crystal displays, solar cells due to its advantages of low cost, high productivity, and excellent electrical conductivity. Notably, flexible-dye-sensitized solar cells (DSSCs) based on polyethylene terephthalate (PET) substrates require low temperature sintering processing conditions. Therefore, low temperature processing conditions have been strongly required for transparent conducting film applications. In this paper, we prepared low temperature-sintered ZnO ceramics employing Li as a sintering aid.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1255-1258
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• 2008

Roll to roll (R2R) system, known as 'web processing', is the process of producing these electronic devices on a roll of flexible plastic. With the need of improved performance and productivity in R2R industry, effective control and on-line supervision for web quality is essential. In this report, we present a system for on-line measurement of wrinkles, one of defects incurring due to compressive stresses developed in the web. This system is able to capture an image generated when a well defined line shape laser beam passes through a transparent web. The system calculates 3D shape information, including the height of the wrinkle on the web, and displays the images for the shape information of the web in real time. By using area scan camera and machine vision laser, this system takes more advantages of setting up as a simple and low cost system compared to the line scan camera systems that widely used in web manufacturing. Specific calibration method and analysis on the achievable accuracy will be discussed.

• Korean Journal of Materials Research
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• v.17 no.7
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• pp.352-357
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• 2007

Since a pattern defects "repair" system using a diode pumped solid state laser for Flat Panel Display (FPD) was suggested, a lot of laser systems have been explored and developed for mass-production microfabrication process. A maskless lithography system using 405 nm violet laser and Digital Micromirror Device (DMD) has been developed for PDP and Liquid Crystal Display (LCD) Thin Film Transistor (TFT) photolithography process. In addition, a "Laser Direct Patterning" system for Indium Tin Oxide (ITO) for Plasma Display Panel(PDP) has been evaluated one of the best successful examples for laser application system which is applied for mass-production lines. The "heat" and "solvent" free laser microfabrications process will be widely used because the next-generation flat panel displays, Flexible Display and Organic Light Emitting Diode (OLED) should use plastic substrates and organic materials which are very difficult to process using traditional fabrication methods.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.687-691
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• 2005

We demonstrated stability-enhanced liquid crystal (LC) displays using pixel-iosolated LC mode in which LC molecules are isolated in pixel by horizontal polymer layer and vertical polymer wall. The device shows good electro-optic properties with external pressure and bending due to the polymer structures. The polymer wall acts as supporting structure from mechanical pressure and maintains the cell gap from bending. Moreover, the polymer layer acts as adhesive for tight attachment of two substrates. We presented various methods to produce the polymer structures by using anisotropic phase separation from LC and polymer composites or patterned micro-structures.