• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04b
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• pp.22-25
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• 2000

ZnS:Cu,Cl 형광체의 여기 및 발광 스펙트럼 측정 결과 주게인 $Cl^-$ 이온과 받게인 $Cu^+$ 이온 사이의 흡수와 발광에 기인하는 peak과 국소화된 발광 중심인 $(CU_2)^{2+}$ 이온의 흡수와 발광에 기인하는 peak이 관측되었다. CuCl의 첨가량이 증가함에 따라 $Cu^+$ 이온의 농도가 증가하게 되어 $(Cu_2)^{2+}$ 이온에 기안하는 발광으로부터 공명 에너지 전달 (Resonant Energy Transfer)의 확률이 높아지기 때문에 513 nm를 중심으로 하는 발광의 세기가 증가하게 된다. 자체 제작한 ZnS:Cu,Cl 형광체를 이용하여 제작한 소자의 휘도 측정결과 400 Hz, 100 V 에서 CuCl 의 첨가량이 0.2 mole% 일 때 휘도가 최대였고, 진동수가 증가함에 따라 휘도가 포화되는 현상이 나타났다. CuCl의 첨가량이 증가함에 따라 513 nm를 중심으로 하는 발광이 강해지고 CIE 좌표값이 녹색영역으로 이동하게 된다. 진동수가 증가하면 인가된 전압의 유지 시간이 짧아지게 되어 발광의 감쇄시간이 긴 513 nm를 중심으로 하는 발광보다 감쇄시간이 짧은 458 nm를 중심으로 하는 발광이 강해지게 되고, CIE 좌표값이 청색영역으로 이동하게 된다.

• Journal of Korean Ophthalmic Optics Society
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• v.8 no.1
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• pp.53-57
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• 2003

R, G, Y, B color lenses Manufactured increasing tinted time by 5 min term. CIE $L^*a^*b^*$ coordination's analysis used spectrophotometer and CIE $L^*a^*b^*$ color system. CIE $L^*a^*b^*$ coordination transfer form about tinted time being $$b^*(Y-B)={\beta}a^*+{\alpha}$$ change to do linear almost. In red case, move in $G{\rightarrow}R$, $B{\rightarrow}Y$ form tinted time increases, and Parameter ${\alpha}$, ${\beta}$ value got each -3.49 and 0.90. In green case, CIE $L^*a^*b^*$ coordination transfer form is $R{\rightarrow}G$, $B{\rightarrow}Y$ form. Got the pure green color color in 10 min's tinted time. Parameter ${\alpha}$, ${\beta}$ value got each -0.72 and -0.55. Get into pure yellow and blue color case tinted time increases. Parameter ${\alpha}$, ${\beta}$ value are 14.11 and 1.58 in yellow, and Parameter ${\alpha}$, ${\beta}$ value are -11.62 and 1.30 in blue color.

• Journal of Korean Ophthalmic Optics Society
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• v.8 no.1
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• pp.59-64
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• 2003

To Photochoromic lens light irradiation side darkening status and fading status photo-transmittance decrease. If remove light irradiation, get into fading state and photo-transmittance has reversibility process that get back originally in state. Get CIE $L^*a^*b^*$ relationship colorimetric using darkening in Photochoromic lens and at fading process. Photochromism's spectrophotometer that produce itself. Darkening and fading state colorimetric ($a^*-b^*$) linear be curvy, and is gradidnt of (-) value. And change lineally. The colorimetric transfer amount is Blue ${\rightarrow}$ Yellow, Red ${\rightarrow}$ Green form. Colorimetric is low $b^*$ value than darkning state in fading state, and Photochromism's coodination transfer moves on the contrary with darkning state, photochoromism relationship estimation method about photochoromic lens can use by colorimetric difference about darkening and fading.

• Applied Chemistry for Engineering
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• v.21 no.5
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• pp.559-563
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• 2010

The representation of color with natural dyes is closely related with the modern well-being life. This study is focused on the representation of target color of the blue, yellow, and red color system, these color sources were originated from the green tea, gardenia, and black rice respectively. The quantitative numerical value of brightness (L), color coordinates (a, b) were designated for the target color, the optimum color nearest to the target value was extracted with the solvent pH, temperature, and extraction time. The longer the extraction time had more thickening color in case of the gardenia. The L-a-b coordinate of extracted color were analyzed with the color difference meter and compared with the target color. The experimental variables were optimized to extract the color of the smallest ${\Delta}E$ with the target color. As a result, the CIE standard value was proposed and the color was represented.

• Journal of the Korean Vacuum Society
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• v.12 no.4
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• pp.235-238
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• 2003

Conventional LED displays use pixels which consist of red, green and blue LEDs of different operation voltages and degradation characteristics. Thus, the circuits are complicated and the display of each color changes independently with the operated time. In order to solve these drawbacks, an LED chip of a short wavelength and an LED lamp with the mixture of red, green, blue fluorescencers and epoxy on the LED chip were studied. The fluorescencers are excited by the light of the LED chip. The LED chip has an active layer of InGaN, a peak wavelength of 408 nm, a FWHM of 13 nm and the CIE index of (0.198, 0.087). White LED lamps were obtained and the CIE index change was observed with the change of the epoxy amount added to the fluorescencers.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.166-169
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• 2007

최근에 정부의 "15/30 LED조명 보급정책"에 힘입어 개발된 8W급 조명용 LED광원의 CIE 색도좌표 (chromaticity coordinate)와 주파장(dominant wavelength)등을 측정 고찰 하였다. 적색(R), 녹색(G), 청색(B), 백색(W)순으로 주파장은 각각 620[nm], 531[nm], 465[nm], 579[nm]이고, 자극순도(excitation purity)는 0.98, 0.82, 0.97, 0.15이며, 휘도순도(colorimetric putity)는 45[%], 16[%], 279[%], 6[%]로 나타났다. Power LED의 최적배치 설계로서, 특히 백색 LED광원의 경우 백열전구(15 lm/W)에 비해 3배 이상의 높은 효율(47.71m/W)을 보였고, 배광측정에서는 78.7%의 효율로 나타났다. 현재 LED광원은 MR16이나 베이스 타입 등의 형태로 제작하여 스탠드, 복도등, 비상유도등, 침실용 등의 용도에 사용되고, 일부는 LED의 원형이나 면(flat)타입으로 가로등이나 투광등으로도 활용되고 있다. 따라서 이들에 대한 각각의 특성들을 제시해 둘 필요성인 인지되어 국내 최초로 개발된 R/G/B/W 8W급 LED광원에 대한 기본적인 광특성 결과를 얻었으며, 이중에서 HB 백색 LED램프의 색도좌표 값을 얻어 CIE표준광과의 색도좌표(x, y) 위치를 비교 검토할 수 가 있었다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.05a
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• pp.3-5
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• 2009

종래의 LED 휘도를 제어하는 방식은 PWM방식이 주로 사용되었다. PWM방식은 지극히 아날로그적인 방식으로 통신 등의 디지털 방식과는 호환이 어려운 단점을 가지고 있다. 본 논문에서는 디지털 방식으로 LED의 휘도를 제어하는 실험을 하였다. LED 구동회로와 디지털논리회로를 제작하여 임의의 디지털 값을 입력한 후 휘도와 CIE x,y좌표를 cs-200으로 측정하여 측정한 색의 x,y좌표가 원하는 색의 x,y좌표영역에 포함될 수 있도록 디지털 입력 값을 최적화시키는 실험을 진행하였다. 본 연구에서 얻은 결과 값을 통하여 디지털 제어로 LED의 휘도를 제어하여 풀 컬러 구현의 가능성을 분석하였다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.2
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• pp.61-65
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• 2009

In this paper, we report on the growth and optical characteristics of white-LED without fluorescent material. The growth of DH(double heterostructure) with AlGaN active layer was performed on a n-GaN/(0001) $Al_{2}O_{3}$ by the mixed-source HVPE and multi-sliding boat. The CRI(color rendering index) of packaging device charged in the range 72-93 with CIE chromaticity coordinates(x=$0.26{\sim}0.34$, y=$0.31{\sim}0.40$). And CCT(correlated color temperature) values was measured $5126{\sim}10406K$ with increasing injection current. The CIE point of conventional phosphor white LED shifts blue region, but cm point of non-phosphor white LED shifts opposite direction. These results show the mixed-source HVPE can be possible to newly fabricate method of phosphor free white LED with high CRI value.

• 전자공학회논문지 IE
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• v.45 no.1
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• pp.1-6
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• 2008

In this paper, the white organic LED with two-wavelength was fabricated using the NPB of blue emitting material and a series of orange color fluorescent dye(Rubrene) by vacuum evaporation processes. The structure of white OLED was ITO/NPB$(200{\AA})$NPB:Rubrene$(300{\AA})$/BCP$(100{\AA})/Alq_3(100{\AA})/Al(1000{\AA})$ and the doping concentration of Rubrene was 0.75 wt%. We obtained the white OLED with CIE color coordinates were x=0.3327 and y=0.3387, and the maximum EL wavelength of the fabricated white organic light-emitting device was 560 nm at applied voltage of 11 V, which was similar to NTSC white color with CIE color coordinates of x=0.3333 and y=0.3333. The turn-on voltage is 1 V, the light-emitting him-on voltage is 4 V. We were able to obtain an excellent maximum external quantum efficiency of 0.457 % at an applied voltage of 18.5 V and current density of $369mA/cm^2$.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.1
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• pp.31-37
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• 2000

In order to color analyze of in Farnsworth Test Panel D-15 using a Protan, Deutan and Tritan test, we introduced the CIE system so that measured the reflectance light spectrum intensity in the 380~780 nm wavelength regions. The color difference of Panel D-15 was depended on the intensity of reflectance ratio in the 400~450 nm, 500~600 nm and more than 650 nm wavelength regions. From the reflectance spectra, we obtained the tristimulus X, Y, Z values, the $L^*a^*b^*$ and $L^*ab$ values of the 3-Dimension CIELAB system in a complement plane and light-darkness axis, the $U^*V^*$ values and the x, y values of chromaticity coordinates.