• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.420-423
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• 2008

The characteristics of $Al_2O_3/Ag/Al_2O_3$ multilayer passivaton prepared by twin target sputtering (TTS) system for organic light emitting diodes. The $Al_2O_3/Ag/Al_2O_3$ multilayer thin film passivation on a PET substrate had a high transmittance of 86.44 % and low water vapor transmission rate (WVTR) of $0.011\;g/m^2$-day due to the surface plasmon resonance (SPR) effect of Ag interlayer and effective multilayer structure for preventing the intrusion of water vapor. Using synchrotron x-ray scattering and field emission scanning electron microscope (FESEM) examinations, we investigated the growth behavior of Ag layer on the $Al_2O_3$ layer to explain the SPR effect of the Ag layer. This indicates that an $Al_2O_3/Ag/Al_2O_3$ multilayer passivation is a promising thin film passivation scheme for organic based flexible optoelectronics.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.186-189
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• 2006

The flexible organic thin film transistor (OTFT) array to use as a switching device for an organic light emitting diode (OLED) was designed and fabricated in the microcontact printing and room temperature process. The gate, source, and drain electrode patterns of OTFT were fabricated by microcontact printing process. The OTFT array with dielectric layer and organic active semiconductor layer formed at room temperature or at a temperature lower than $40^{\circ}C$. The microcontact printing process using SAM and PDMS stamp made it possible to fabricate OTFT arrays with channel lengths down to even submicron size, and reduced the fabrication process by 10 steps compared with photolithography. Since the process was done in room temperature, there was no pattern shrinkage, transformation, and bending problem appeared. Also, it was possible to improve electric field mobility, to decrease contact resistance, to increase close packing of molecules by SAM, and to reduce threshold voltage by using a big dielectric.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.973-976
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• 2006

In this paper, the inorganic multi-layer encapsulation of thin film was newly adopted to protect the organic layer from moisture and oxygen. Using the electron beam, Sputter, inorganic multi-layer thin-film encapsulation was deposited onto the Ethylene Terephthalate(PET) and their interface properties between inorganic and organic layer were investigated. In this investigation, the SiON $SiO_2$ and parylene layer showed the most suitable properties. Under these conditions, the water vapor transmission rate (WVTR) for PET can be reduced from level of $0.57g/m^2/day$ (bare substrate) to $1^{\ast}10^{-5}g/m^2/day$ after application of a SiON and $SiO_2$ layer. These results indicate that the $PET/SiO_2/SiON/Parylene$ barrier coatings have high potential for flexible organic light-emitting diode(OLED) applications.

• 한국전기전자재료학회논문지
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• 제19권1호
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• pp.71-74
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• 2006

In this paper, we investigated the characterization of silicon oxide(SiOx) thin film on Ethylene Terephthalate(PET) substrates by e-beam deposition for transparent barrier application. The temperature of chamber increases from $30^{\circ}C$ to $110^{\circ}C$, the roughness increase while the Water vapor transmission rate (WVTR) decreases. Under these conditions, the WVTR for PET can be reduced from a level of $0.57 g/m^2/day$ (bare subtrate) to $0.05 g/m^2/day$ after application of a 200-nm-thick $SiO_2$ coating at 110 C. A more efficient way to improve permeation of PET was carried out by using a double side coating of a 5-${\mu}m$-thick parylene film. It was found that the WVTR can be reduced to a level of $-0.2 g/m^2/day$. The double side parylene coating on PET could contribute to the lower stress of oxide film, which greatly improves the WVTR data. These results indicates that the $SiO_2$ /Parylene/PET barrier coatings have high potential for flexible organic light-emitting diode(OLED) applications.

• 한국기계가공학회지
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• 제19권8호
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• pp.43-49
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• 2020

The growth of the AR/VR market due to the advent of the 4th Industrial Revolution begins with the development of the display industry. The development of OLED and flexible displays is further accelerated by the development of R2R technology. Micro-processing technology using a fast tool servo (FTS), the core technology in R2R processes, is making technological progress in increasingly diverse ways. This paper proposes a method to develop an FTS for horizontal driving and presents this method through experiments and analyses. To develop a swing-type FTS based on a seesaw motion, a rotational moment hinge structure was designed for each type, and research was conducted to determine an effective design method. A cantilever-based swing-type FTS was developed in two variations: one with single-side hinges and another with dual-side hinges. The parameters in the design of the swing-type FTS are rotational moment, natural frequency, and material selection. In conclusion, an FTS with a single-side hinge demonstrates the high performance required for micro processing.

• 한국정밀공학회지
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• 제26권11호
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• pp.70-76
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• 2009

Web tension control system recently have been applied to OLED(Organic Light-Emitting Diode), RFID of flexible material, e-Paper and PLED(Polymeric LED) and various web control algorithms have being developed for higher productivity and product quality These system need an accuracy model to design and implement controller. In this paper, the web tension control system with dancer roll is mathematically modeled. Mathematical model consists of 8 subsystems and each subsystems can be described as impedance structure which connected by velocity and tension. Mathematical model is different from the estimated model at high frequency range because of structure dynamics which is ignored on mathematical model. The estimated model is derived using ARMAX model. The controller is designed using the estimated model. The step response of the estimated model are compared with that of physical model for a validation of estimated model. The experimental results show a good match between them.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.198.2-198.2
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• 2014

We investigated change of the electronic structure, chemical states and elements ratio in graphene film by using photoelectron spectroscopy (PES). The graphene electrode has attracted considerable interest due to its possible applications in flexible organic light emitting diodes (F-OLEDs). However, to use the graphene for OLEDs, sufficient increase of work function is required, that is related with hole injection barrier. Plasma treatment is one of the most widely used method in OLEDs to increase the work function of the anode such as indium tin oxide (ITO). In this work, we used the plasma treatment, which is generated by various gas types such as O2, and Ar to increase the work function of the graphene film. From these results, we discuss the relation among the change of work function, plasma power, plasma treatment time and gas types.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.234.2-234.2
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• 2014

Organic light emitting diode (OLED) is considered as the next generation flat panel displays due to its advantages of low power consumption, fast response time, broad viewing angle and flexibility. For the flexible application, it is essential to develop thin film encapsulation (TFE) to protect oxidation of organic materials from oxidative species such as oxygen and water vapor [1]. In many TFE research, the inorganic film by atomic layer deposition (ALD) process demonstrated a good barrier property. However, extremely low throughput of ALD process is considered as a major weakness for industrial application. Recently, there has been developed a high throughput ALD, called 'spatial ALD' [2]. In spatial ALD, the precursors and reactant gases are supplied continuously in same chamber, but they are separated physically using a purge gas streams to prevent mixing of the precursors and reactant gases. In this study, the $Al_2O_3$ thin film was deposited by spatial ALD process. We characterized various process variables in the spatial ALD such as temperature, scanning speed, and chemical compositions. Water vapor transmission rate (WVTR) was determined by calcium resistance test and less than $10-^3g/m^2{\cdot}day$ was achieved. The samples were analyzed by x-ray photoelectron spectroscopy (XPS) and field emission scanning electron microscope (FE-SEM).

• 한국전기전자재료학회논문지
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• 제19권3호
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• pp.255-259
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• 2006

In this paper, the inorganic-organic thin film encapsulation layer was newly adopted to protect the organic layer from moisture and oxygen. Using the electron beam, Sputter and Spin-Coater system, the various kinds of inorganic and organic thin-films were deposited onto the Ethylene Terephthalate(PET) and their interface properties between organic and inorganic layer were investigated. In this investigation, the SiON and Polyimide(PI) layer showed the most suitable properties. Under these conditions, the WVTR(water vapour transition rate) for PET can be reduced from level of $0.57\;g/m^2{\cdot}day$ (bare subtrate) to $1{\times}10^{-5}\;g/m^2{\cdot}day$ after application of a SiON and Polyimide layer. These results indicates that the SiON/PI/SiON/PI/PET barrier coatings have high potential for flexible organic light-emitting diode(OLED) applications.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.93-93
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• 2011

The Indium Zinc Tin Oxide (IZTO) and Indium Tin Oxide (ITO) thin films are grown on PI substrate at different substrate temperature by pulsed DC magnetron sputtering with a sintered ceramic target of IZTO (In2O3 70 wt.%, ZnO 15 wt.%, SnO2 15 wt.%) and ITO (In2O3 90wt.%, SnO2 10wt.%). The structural, electrical, and optical properties are investigated. The IZTO thin films deposited at low temperature showed relatively low electrical resistivity compared to ITO thin films deposited at low temperature. As a result, we could prepare the IZTO thin films with the resistivity as low as $5.6{\times}10^{-4}({\Omega}{\cdot}m)$. Both of the films deposited on PI substrate showed an average transmittance over 80% in visible range (400.800nm). Overall, IZTO thin film is a promising candidate as an alternative TCO material to ITO in flexible and OLED devices.