• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2169-2171
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• 2005

A new structure is proposed to achieve a low sustaining voltage and high luminous efficacy. By measuring minimum sustaining voltage(Vs) discharge current(Ion), discharge(Ioff), and brightness of the light from a 4-inch ac-PDP, performances of the conventional structure and proposed structure are compared. When compared with the conventional structure, proposed structure showed 6.5% Vsm improvement, 22% luminance improvement and 20% light dispersion improvement at the Ne-Xe(8%) gas mixture of 400 torr.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.379-379
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• 2007

The characteristics of indium-zinc-tin-oxide (IZTO)-Ag-IZTO multilayer grown on a PET substrate were investigated for flexible organic light-emitting diodes. The IZTO-Ag-IZTO (IAI) multilayer anode exhibited a remarkably reduced sheet resistance of 4 ohm/sq and a high transmittance of 84%, despite the very thin thickness of the IZTO (30 nm) layer. In addition, it was shown that electrical and optical properties of IAI anodes are critically dependent on the thickness of the Ag layer, due to the transition of Ag atoms from distinct islands to continuous films at a critical thickness (14 nm). Moreover, the IAI/PET sample showed more stable mechanical properties than an amorphous ITO/PET sample during the bending test due to the existence of a ductile Ag layer. The current density voltage-luminance characteristics of flexible OLEDs fabricated on an IAI/PET substrate was better than those of flexible OLEDs fabricated on an ITO/PET substrate. This indicates that IAI multilayer anodes are promising flexible and transparent electrodes for flexible OLEDs.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.64-65
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• 2007

High-efficiency white organic light-emitting diodes (WOLEDs) were fabricated with two emissive layers and exciton blocking layer was sandwiched between two phosphorescent dyes which were, bis(3,5-Difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl) iridium III (Flrpic) as blue emission and a newly synthesized red phosphorescent material guest, Bis(5-benzoyl-2-phenylpyridinato-C,N)iridium(III) (acetylacetonate) ((Bzppy)2Ir(III)acac). This exciton blocking layer prevents a triple-triple energy transfer between the two phosphorescent emissive layers with balanced emission of blue and red. The white device showed the Commission Internationale d'Eclairage (CIEx,y) coordinates of (0.34, 0.40) at the maximum luminance of $24100\;cd/m^2$ and maximum luminous efficiency of 22.4 cd/A, respectively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.2018-2019
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• 2007

Organic light emitting diodes (OLEDs) show a lot of advantages for display purposes. Because OLEDs provide white light emission with a high efficiency and stability, it is desirable to apply OLEDs as an illumination light source and back light in LCD displays. We synthesized new emissive materials, namely $Zn(HPB)_2$ and Zn(HPB)q, which have a low molecular compound and thermal stability. We studied white OLEDs using $Zn(HPB)_2$ and Zn(HPB)q. The fundamental structures of the white OLEDs were ITO / NPB (40 nm) / $Zn(HPB)_2$ (40 nm) / Zn(HPB)q (20 nm) / LiAl (120nm). As a result, we obtained a maximum luminance of $15325cd/m^2$ at a current density of $997\;mA/cm^2$. The CIE (Commission International de l'Eclairage) coordinates are (0.28, 0.35) at an applied voltage of 9.75 V.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.447-450
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• 2003

In this paper, new luminescent material, 6,11-dihydoxy-5,12-naphtacene-dione Alq3 complex (Alq2-Ncd), 1,4-dihydoxy-5,8-naphtaquinone Alq3 complex(Alq2-Nq) was synthesized. And extended efforts had been made to obtain high-performance electroluminescent(EL) devices, since the first report of organic light-emitting diodes(OLEDS) based on tris-(8-hydroxyquinoline) aluminum(Alq3). We have performed investigate characterization of the materials. Current-voltage characteristics, luminance-voltage characteristics and luminous efficiency were measured by Flat Panel Display Analysis System(Model 200-AT) at room temperature. An intensive research is going on to improve the device efficiency using the hole injection layer, different electrodes, and etc. By using the hole injection layer, the charge-injection can be controlled and the stability could be improved. This study indicates not only the sterical effect but also some other effects would be responsible for the change of the emission wavelength.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.69-70
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• 2006

We studied increasement of efficiency of Organic Light-emitting Diodes depending on thickness variation of LiF, Material of Electron Injection Layer in structure of ITO/Hole Injection Layer (PTFE)/Hole Transportion Later (TPD)/Emitting Layer (Alq3)/Electron Injection Layer (LiF)/Al. TPD and $Alq_3$ is deposited as rate of 1.3~1.5 [${\AA}/s$] in high vacuum ($5{\times}10^{-6}$ [torr]). In result of these studies, we can know maximum efficiency in 0.7 [nm], thickness of LiF. And samples with electron injection material are increased about 5-fold in maximum efficiency in compare with sample without electron injection material.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.416-417
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• 2006

Organic light emitting diodes (OLEDs) show a lot of advantages for display purposes. Because OLEDs provide white light emission with a high efficiency and stability, it is desirable to apply OLEDs as an illumination light source and back light in LCD displays. We synthesized new emissive materials, namely [2-(2-hydroxyphenyl)benzoxazole] ($Zn(HPB)_2$) and [(2-(2-hydroxyphenyl)benzoxazole)(8-hydoxyquinoline)] (Zn(HPB)q), which have a low molecular compound and thermal stability. We studied white OLEDs using $Zn(HPB)_2$ and Zn(HPB)q. The fundamental structures of the white OLEDs were ITO/PEDOT:PSS (23 nm)/NPB (40 nm)/$Zn(HPB)_2$ (40 nm)/Zn(HPB)q (20 nm)/$Alq_3$ (10 nm)/LiAl (120 nm). As a result, we obtained a maximum luminance of $15325\;cd/m^2$ at a current density of $997\;mA/cm^2$. The CIE(Commission International de l'Eclairage) coordinates are (0.28, 0.35) at an applied voltage of 9.75 V.

• 한국전기전자재료학회논문지
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• 제24권10호
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• pp.822-833
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• 2011

A Xe plasma flat lamp, which has been noticed as a new eco-friendly LCD (liquid crystal display) backlight, requires the improvement of the luminance and the luminous efficiency although it has several advantages. To improve the performance of a lamp, it is necessary to understand the effects of discharge variables on the luminous characteristics of the lamp. Since it is difficult to diagnose a lamp discharge experimentally, the numerical analysis can be used instead. In this study, the luminous characteristics of a planar type Xe plasma flat lamp were analyzed with the variation of an input voltage and a pulse frequency. The numerical analysis of a lamp discharge was then performed using a RCT (relaxation continuum) model and a LFA (local field approximation) model. The comparison with the experimental results showed that the RCT model is valid for the numerical analysis of the flat lamp. The numerical analysis also showed that the modifications of a high frequency component and a voltage falling rate in the input voltage waveform could improve the luminous characteristics of the lamp.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.68-68
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• 2010

Electroluminescence (EL) characteristics of green-emission ZnS:Cu,Cl-based ac-type inorganic powder electroluminescent structures were examined by inserting carbon nanotubes (CNTs) into or next to the dielectric layer. For the top-emission type EL structure, where the luminescent light was emitted from the top of the structure, was fabricated by assembling in order, a top electrode, an emitting layer, a dielectric layer, and a bottom electrode from the top. $BaTiO_3$ powder mixed with CNTs was used as a dielectric layer or CNTs were deposited between the bottom electrode and $BaTiO_3$ dielectric layer in order to improve the role of the dielectric layer in the structure. Luminance of an EL structure with CNTs inclusion was greatly enhanced possibly due to the high dielectric constant in the dielectric layer of $BaTiO_3$/CNTs, which is one of hot research topics utilizing nano-objects for intensifying dielectric constant and reducing dielectric loss at the same time. A variation on the CNTs themselves and their inclusion methods in the dielectric layer has been exhorted, and the underlying mechanism for the role of CNTs in the EL structure will be explained in the poster. In order to extend the flexibility of EL devices, EL devices were fabricated on the paper substrate and their performance was compared other EL devices on the plastic-based substrate.

• 한국광학회지
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• 제30권3호
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• pp.101-105
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• 2019

LCD의 광 효율을 향상시키기 위해 LCD backlight unit (BLU)의 광원으로 적색, 녹색, 청색의 광원을 사용하였으며, RGB 광은 lenticular lens array (LLA)를 통해 집광되어 각각 컬러 필터의 적색, 녹색, 청색 필터에 색일치되는 조건으로 광이 지나도록 설계하여 시뮬레이션하였다. 광원의 위치에 따라 Type-A와 Type-B 두 가지 방식으로 시뮬레이션을 진행하였으며, 그 결과 LLA를 사용하지 않았을 때와 비교하여 Type-A는 휘도가 210%로 상승하였으며, Type-B는 270% 상승함을 확인하였다. LLA의 최적의 조건은 렌즈의 높이가 $25{\mu}m$, 렌즈 간의 간격이 $3{\mu}m$일 때, 효율이 최대가 됨을 확인하였다.