• Bulletin of the Korean Chemical Society
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• v.33 no.11
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• pp.3645-3650
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• 2012

Two new blue emitting cationic iridium(III) complexes with two substituted 2-phenlypyridine ligands as main ligands and one 2,2'-biimidazole as an ancillary ligand, $[(L1)_2Ir(biim)]Cl$ (1) and $[(L2)_2Ir(biim)]Cl$ (2), where L1 = 2-(2',4'-difluorophenyl)-4-methylpyridine, L2 = 2-(2',4'-difluoro-3'-trifluoromethylphenyl)-4-methylpyridine and biim = 2,2'-biimidazole, were synthesized for applications in phosphorescent organic light-emitting diodes (PhOLEDs). Their photophysical, electrochemical and electroluminescent (EL) device performances were examined. The photoluminescent (PL) spectra revealed blue phosphorescence in the 450 to 485 nm range with a quantum yield of more than 10%. The iridium(III) compounds studied showed good solubility in organic solvents with no solvatochromism dependent on the solvent polarity. The solution-processed OLEDs were prepared with the configuration, ITO/PEDOT:PSS (40 nm)/mCP:Ir(III) (70 nm)/OXD-7 (20 nm)/LiF (1 nm)/Al (100 nm), by spin coating the emitting layer containing the mCP host doped with the iridium phosphors. The best performance of the fabricated OLEDs based on compound 1 showed an external quantum efficiency of 4.5%, luminance efficiency of 8.52 cd $A^{-1}$ and blue emission with the CIE coordinates (x,y) of (0.16, 0.33).

• Journal of the Korea Fashion and Costume Design Association
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• v.14 no.4
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• pp.151-162
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• 2012

Regarding experimental study on the dyeing properties of natural dye, I have dyed silk fabric with Styphnolobium japonicum, sappan wood, and indigo. The results of the experiment have been analysed by wavelength of maximum absorption, K/S and CIE Lab chromaticity co-ordinated. The results are as follows: In case of complex dyeing using Styphnolobium japonicum and sappan wood, dyeing with sappan wood, which is red related color, after dyeing with Styphnolobium japonicum, which is yellow related color, is more efficient. When dyeing was maden by complex of Styphnolobium japonicum and sappan wood, Dyeing method by the order of "Styphnolobium japonicum${\rightarrow}$sappan wood${\rightarrow}$mordanting" made the best result of complex dyeing. In case of complex dyeing using Styphnolobium japonicum and Indigo, dyeing with Styphnolobium japonicum after the indigo made the best result. When dyeing with indigo first, and then Styphnolobium japonicum, yellow color was not well dyed, and low level of saturation caused lusterless color. Ordering of Styphnolobium japonicum${\rightarrow}$sappan wood${\rightarrow}$indigo made the best result of complex dyeing in case of complex dying with Styphnolobium japonicum and indigo. Dyeing order, sappan wood first and then indigo last method shown 560~640 nm wavelength of maximum absorption which most color was blue related. In contrast, Indigo first and then sappan wood method shown 460~560nm wavelength of maximum absorption which color was red related. Complex dyeing with sappan wood and indigo was showing lusterless color. In case of dyeing with red and blue, dyeing with sappan wood and indigo was not appropriate.

• Journal of Technologic Dentistry
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• v.36 no.4
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• pp.247-253
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• 2014

Purpose: The aim of this study was to evaluate the effect of colored zirconia with different coloring liquids. Methods: Total 30 specimens were prepared. Specimens were classified into 6 groups: IPS e.max Ceram(P), Uncolored zirconia(C), VITA In-Ceram$^{(R)}$2000 YZ LL1(L), Zirkonzahn coloring liquid(Z), Wieland coloring liquid(W), and Kuwotech coloring liquid(K). Four different types of zirconia coloring liquid, VITA In-Ceram$^{(R)}$ 2000 YZ LL1(VITA Zahnfabrik, Germany), Zirkonzahn coloring liquid(Zirkonzahn, Italy), Wieland coloring liquid(Wieland, Germany), Kuwotech coloring liquid(Kuwotech, Korea) were used to fabricate colored zirconia by using infiltrating method and then completely sintered. The color of the all specimens was measured using the spectrophotometer(CM-2600d, Konica Minolta, Japan) and expressed in terms of the 3-coordinated values(CIE $L^*a^*b^*$). Color differences were calculated using the equation $${\Delta}E^*=[({\Delta}L^*)^2+({\Delta}a^*)^2+({\Delta}b^*)^2]^{1/2}$$. Results: $L^*a^*b^*$ values of the colored zirconia were affected by the coloring liquids. The uncolored zirconia(C) group showed the highest $L^*$ value and zirkonzahn coloring liquid(Z) group showed the lowest $L^*$ value. Zirkonzahn coloring liquid(Z) showed the highest $a^*$ value and VITA In-Ceram 2000 YZ LL1(L) group showed the highest $b^*$ value. Generally, the color difference(${\Delta}E^*$) in all groups showed higher than 3.7 except between IPS e.max Ceram(P) and wieland coloring liquid(W) group. Conclusion: Within the limitations of this study, various coloring liquids influenced the $L^*$, $a^*$, and $b^*$ values of colored zirconia. IPS e.max Ceram(P) and wieland coloring liquid(W) group did not show clinically perceiving color difference.

• The Journal of the Korean dental association
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• v.58 no.8
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• pp.476-485
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• 2020

The purpose of this study was to analyze the color distribution of the maxillary primary central and lateral incisors using a dental spectrophotometer. Color measurements of maxillary primary central and lateral incisors of 32 pediatric patients aged 2 to 6 years were performed using SpectroShade Handy Dental Type 713000 (Serial No. HDL2678, MHT, Verona, Italy) by one researcher in the same clinic. CIE L*, a*, b* values of total surfaces and cervical, middle, incisal region were recorded. L* values were higher and a* values were lower in the primary central incisors than those in primary lateral incisors, but b* values didn't show statistical difference. L* values of the middle region were the highest, and a* and b* values decreased from the cervical region to the incisal region. There were significant color differences between each region, and ΔE*_ab between each region were greater than ΔE*_ab between the primary central and lateral incisors. For esthetic restorations of primary incisors, it is necessary to consider the color differences between each region rather than those between the primary central and lateral incisors.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.4C
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• pp.350-357
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• 2010

In this paper, we present an auto-range fast bilateral filter (FBF) for high-dynamic-range (HDR) images, which increases computation speed by using adaptive standard deviations for range filter (RF) of FBF in iCAM06. Many images that cover the entire dynamic range of the scene with different exposure times are fused into one High Dynamic Range (HDR) image. The representative algorithm for HDR image rendering is iCAM06, which is based on the iCAM framework, such as the local white point adaptation, chromatic adaptation, and the image processing transform (IPT) uniform color space. FBF in iCAM06 uses constant standard deviation in RF. So, it causes unnecessary FBF computation in high stimulus range with broad and low distribution. To solve this problem, the low stimulus image and high stimulus image of CIE tri-stimulus values (XYZ) divided by the threshold are respectively processed by adaptive standard deviation based on its histogram distribution. Experiment results show that the proposed method reduces computation time than the previous FBF.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.2
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• pp.124-131
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• 2016

Several research works for finding and optimizing the methods of dispensing high viscosity phosphor used in the fabrication of white LED's are currently in progress. High viscosity phosphor dispensing with a high accuracy is crucial because the dispensing rate and uniformity directly affect parameters such as the CIE chromaticity diagram, color temperature and luminous flux of white LED's. This study presents a novel method of dispensing high viscosity phosphor using electrohydrodynamic printing. The dispensing rate was optimized less than 0.01 mg phosphor using experiments and optimizing the process parameters including the standoff distance from the nozzle to the substrate, ink supply pressure, and multi-step pulsed waveform magnitude ratio. The dispensing rate was measured by dispensing 20 dots using drop-on-demand with the optimized parameters, and the experiments were repeated 10 times to maximize the data accuracy. The average dispensing rate that can be reliably used for high viscosity phosphor dispensing was 0.0052 mg.

• Journal of the Semiconductor & Display Technology
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• v.4 no.2 s.11
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• pp.15-19
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• 2005

The organic light-emitting devices(OLEDs) based on fluorescence have low efficiency due to the requirement of spin-symmetry conservation. By using the phosphorescent material, the internal quantum efficiency can reach 100$\%$, compared to 25$\%$ in case of the fluorescent material [1]. Thus recently phosphorescent OLEDs have been extensively studied and showed higher internal quantum efficiency than conventional OLEDs. In this study, we have applied a new Ir complex as a red dopant and fabricated a red phosphorescent OLED on a flexible PC(Polycarbonate) substrate. Also, we have investigated the electrical and optical properties of the devices with a structure of A1/LiF/Alq3/(RD05 doped)BAlq/NPB/2-TNAIA/ITO/PC substrate. Our device showed the lightening efficiency of > 30 cd/A at an initial brightness of 1000 cd/$m^{2}$. The CIE(Commission Internationale de L'Eclairage) coordinates for the device were (0.62,0.37) at a current density of 1 mA/$cm^{2}$. In addition, although the sheet resistance of ITO films on PC substrate is higher than that on glass substrate, the flexible OLED showed much better lightening efficiency without much increase in operating voltage.

• Journal of the Semiconductor & Display Technology
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• v.10 no.1
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• pp.23-26
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• 2011

New organic light-emitting diodes with structure of ITO/DNTPD/TAPC/$Bebq_2/Bebq_2$:RP-411/ET-137/LiF/Al using the selective doping of 5% RP-411 in a single $Bebq_2$ host in the two wavelength(green, red) emitter formation were proposed and characterized. In the experiments, with a 300${\AA}$-thick undoped emitter of $Bebq_2$, three kinds of devices with different thicknesses of 30${\AA}$, 40${\AA}$ and 50${\AA}$ in the doped emitter of $Bebq_2$:RP-411 were fabricated. The electroluminescent spectra showed two peak emissions at the same wavelengths of 511 nm and 622 nm for the fabricated devices. When the device with a 30${\AA}$-thick doped emitter is referred as "D-1", the device with a 40${\AA}$-thick doped emitter is referred as "D-2" and the device with a 50${\AA}$-thick doped emitter is referred as "D-3", the relative intensity of 622 nm to 511 nm at two wavelength peaks was higher in the D-2 and the D-3 than in the D-1. The devices of D-1, D-2 and D-3 showed the color coordinates of (0.43, 0.46), (0.46, 0.44) and (0.48, 0.43) on the CIE chart, respectively.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.39 no.2
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• pp.11-16
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• 2002

In this paper, single-layer white organic light emitting device was fabricated on ITO glass substrate using PVK as host, Bu-PBD as electron transport layer, Nile Red, Coumarin 6, TPB as red, green, blue color fluorescent dyes. The red, green, blue organic light emitting devices were fabricated respectively. After the characteristic analysis of each color device, the white organic light emitting device was fabricated with optimized condition of each color device by spin coating method. we obtained white emission CIE coordination of (0.32, 0.34) and luminescence of 785cd/$m^2$ at driving voltage of 20V with condition of PVK(70wt%), Bu-PBD(30wt%), Nile Red(0.015mol%), Coumarin 6(0.04mol%), TPB(3mol%). 

• Journal of the Semiconductor & Display Technology
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• v.7 no.2
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• pp.49-53
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• 2008

The yellow base polymer light emitting diodes(PLEDs) with double emission and hole blocking layers were prepared to improve the light efficiency. ITO(indium tin oxide) and PEDOT : PSS[poly(3,4-ethylenedioxythiophene) : poly(styrene sulfolnate)] were used as cathode and hole transport materials. The PFO[poly(9,9-dioctylfluorene)] and MEH-PPV[poly(2-methoxy-5(2-ethylhe xoxy)-1,4-phenylenevinyle)] were used as the light emitting host and guest materials, respectively. TPBI[Tpbi1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene] was used as hole blocking layer. To investigate the optimization of device structure, we prepared four kinds of PLED devices with different structures such as single emission layer(PFO : MEH-PPV), two double emission layer(PFO/PFO : MEH-PPV, PFO : MEH-PPV/PFO) and double emission layer with hole blocking layer(PFO/PFO : MEH-PPV/TPBI). The electrical and optical properties of prepared devices were compared. The prepared PLED showed yellow emission color with CIE color coordinates of x = 0.48, y = 0.48 at the applied voltage of 14V. The maximum luminance and current density were found to be about 3920 cd/$m^2$ and 130 mA/$cm^2$ at 14V, respectively for the PLED device with the structure of ITO/PEDOT : PSS/PFO/PFO : MEH-PPV/TPBI/LiF/Al.