• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1129-1132
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• 2005

We report state-of-the-art phosphorescent organic light emitting diode lifetime and efficiency performances for a range of emission colors. Lifetimes in excess of 100,000hrs have been demonstrated at display luminance levels for saturated red emission. External quantum efficiencies close to the theoretical maximum (e.g. 23% without enhanced optical output coupling) are also demonstrated for devices with lifetimes in excess of 15,000hrs at a display level luminance for both orange red and green.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.837-840
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• 2007

We propose a novel digital driving method for AM-OLED (Active Matrix-Organic Light Emitting Diode) display. Proposed method modulates $V_{DD}$ so that luminance may be weighted in accordance with the bit significance. We can increase the minimum emission time or slower scan circuits are applicable by using proposed method.

• Journal of the Semiconductor & Display Technology
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• v.22 no.1
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• pp.23-27
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• 2023

Organic light-emitting diode(OLED) is very thin organic films which are hundreds of nanometers. Unlike bottom-emission OLED(BEOLED), top-emission OLED(TEOLED) emits light out the front, opaque moisture absorbents or metal foils can't be used to prevent moisture and oxygen. And it is difficult to have flexible characteristics with glass encapsulation, so thin film encapsulation which can compensate for those two disadvantages is mainly used. In this study, Al₂O₃ thin films by atomic layer deposition(ALD) were examined by changing the argon gas purge flow rate and we applied this Al₂O₃ thin films to the encapsulation of TEOLED. Ag / ITO / N,N'-Di-[(1-naphthyl)-N,N'-diphenyl]-1,1'-biphenyl-4,4'-diamine / tris-(8-hydroxyquinoline) aluminum/ LiF / Mg:Ag (1:9) were used to fabricate OLED device. The characteristics such as brightness, current density, and power efficiency are compared. And it was confirmed that with a thickness of 40 nm Al₂O₃ thin film encapsulation process did not affect OLED properties. And it was enough to maintain a proper OLED operation for about 9 hours.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.675-678
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• 2007

In organic light emitting diodes (OLEDs), the electrons and holes need to be injected efficiently to obtain the best device performance. This means that a small injection barrier height at the ITO/organic interface is required. In this study, the surface of the ITO anode was treated with an Aluminum oxynitride (AlON).

• Journal of the Korean Applied Science and Technology
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• v.18 no.1
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• pp.7-11
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• 2001

White emission is important for applying organic EL devices to full-color flat panel display and backlight for liquid crystal display. In order to obtain white emission, the use of a light-emitting material which shows the white emission by itself is advantageous for these applications because of its high reliability and productivity. A chelate-metal complex such as zinc bis(2-(2-hydroxyphenyl) benzothiazolate) ($Zn(BTZ)_{2}$ was known to emit white light with a broad electroluminescence. In this study, the electroluminescent characteristics of $Be(BTZ)_{2}$ and $Mg(BTZ)_{2}$, as well as $Zn(BTS)_2$ were investigated using organic electroluminescent devices with the structure of ITO/TPD/ $Be(BTZ)_{2}$, $Mg(BTZ)_{2}$, or $Zn(BTZ)_{2}/Al$. It was found that the device containing $Be(BTZ)_{2}$ showed the highest power efficiency.

• Vacuum Magazine
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• v.1 no.2
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• pp.24-29
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• 2014

Display is a key component in electronic devices. OLED is growing very fast recently due to the explosion of the smart phone market although still LCD is the dominating display technology in the display market at the moment. Also needs for the large area and high resolution TVs and flexible displays are increasing these days. Especially flexible display is expected to be one of the key technologies in mobile devices requiring small device size and large display size. Contrary to the conventional displays, flexible display requires organic materials for the substrate, the active driving element and also for the display element. Plastic film as a substrate, organic semiconductor as an active component of the transistor and organic light emitting materials or electronic paper as a display element are studied actively. In this article, mainly backplane technologies such as substrates and the transistor materials for flexible display will be introduced.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.6
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• pp.511-514
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• 2008

2-wavelength type white OLED devices have been made consisted of two layers; a layer with blue light emitting DPVBi host and other EML layer with yellow emitting rubrene dopant. New method to get white emitting device has been suggested by varying thicknesses of the DPVBi layer. The ITO/2-TNATA($150{\AA}$)/NPB($350{\AA}$)/DPVBi($35{\AA}$)/DPVBi:rubrene (2wt%,$200{\AA}$)/DPVBi($100{\AA}$)/Alq_3($50{\AA}$)/LiF($5{\AA}$)/Al($1000{\AA}$) structure has showed optimum results in CIE coordinates of (0.3233, 0.33). OLED devices with this structure has properties of $1.2d/m^2$ at turn-on voltage of 3.9V and $1037cd/m^2$ at 7.9V. This structure has advantages of simple fabrication and easy to emit the white color.

• Journal of the Semiconductor & Display Technology
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• v.3 no.3
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• pp.31-35
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• 2004

A blue light emitting diode with 8 periods InGaN/GaN multi-quantum well structure grown by metal-organic chemical vapor deposition was fabricated with the inclusion of the metal-interconnection process in order to integrate the chips for light lamp. The quantum well structure provides the blue light photoluminescence peaked at 479.2 nm at room temperature. As decreasing the temperature to 20 K, the main peak was shifted to 469.7 nm and a minor peak at 441.9 nm appeared indicating the quantum dot formation in quantum wells. The current-voltage measurement for the fabricated LED chips shows that the metal-interconnection provides good current path with ohmic resistance of 41 $\Omega$.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1215-1218
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• 2008

We investigate the effect of a light emitting layer (EML) sequence and an interlayer on the performance of the phosphorescent-fluorescent mixed white organic light emitting diodes. Two types of phosphorescent-fluorescent mixed system were evaluated. The proper position of each primary color EML was crucial to obtain best performance in each system whereas the effect of an interlayer was found to be different in both systems.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1591-1594
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• 2006

In this work, we fabricated efficient white organic light emitting device (WOLED) by the stack of complementary fluorescent dye-doped layers, Effect of dye-doping ratio and thickness of each layers on WOLED efficiency and emission spectrum was investigated. Moreover, out-coupling efficiency enhancement using microlens array was analyzed for bottom and top-emitting device architecture, leading to higher light extraction properties.