• Title/Summary/Keyword: chromaticity

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Efficient White Organic Light-Emitting Diodes (WOLEDs) with Device Structure Modification

  • Kim, Jun-Ho;Seo, Ji-Hoon;Seo, Ji-Hyun;Hyung, Gun-Woo;Lee, Kum-Hee;Yoon, Seoung-Soo;Kim, Young-Kwan
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08b
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    • pp.1403-1406
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    • 2007
  • An effective WOLED structure was demonstrated which improved a luminous efficiency and white color chromaticity independent on applied bias by employing effective carrier transporting layer, without any alteration of emissive materials. The modified WOLEDs exhibited 2 times higher luminous efficiency than the control device and showed balanced white emission during an operation.

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Design and farbrication of a reflective multicolor STN-LCD panel (반사형 칼라 STN-LCD 패널의 설게 및 제작)

  • 강기형;문정민;윤태훈;김재창;남기곤;이기동;이응상
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.33A no.12
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    • pp.90-96
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    • 1996
  • Optical conditions of a reflective multicolor STM-LCD based on the electrical control of birefrignece are analyzed on the CIE chromaticity diagram. The luminance and the area of the locus on the cIE chromaticity diagram are the two factors to be considered in the design of an LC cell to display white, red, green, and blue. The characteristics of a test cell agrees well with numerical simulation. A completed 320$\times$240 module is addressed by a designed PWM driving circuit.

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Optimization of resolution and color reproduction for color CRT monitor by control of contrast and brightness levels (칼라 CRT 모니터의 화면밝기와 명암대비 레벨 조절에 의한 분해능과 색재현의 최적화)

  • 김태희;이윤우;조현모;송재봉;이인원;박승옥
    • Korean Journal of Optics and Photonics
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    • v.10 no.5
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    • pp.379-385
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    • 1999
  • The characteristics of image quality of a color CRT (cathode ray tube) monitor are studied by changing the contrast and brightness levels. The resolution is assessed by SQRI (square root integral) measured at 9 different combinations of the contrast and brightness levels. The chromaticity coordinates and luminances of red-green-blue channels as a function of the digital value are measured at these combinations and the relationships among the constant-channel chromaticity, color gamut, maximum luminance of a white point with the channel independence are analyzed. From the results, the optimized combination of levels is obtained.

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Research about evaluating the spectrum of WOLED

  • Lu, Lili;Chen, Wenbin;Shao, Wanli
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.961-965
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    • 2006
  • White organic LED spectrum for lighting and displaying should be designed for high luminous efficiency as well as good chromaticity coordinate, pleasant correlated color temperature and color rendering. A program based on Matlab was made to make these calculations convenient. The chromaticity coordinate and luminous efficiency was calculated according to the CIE 1931 colorimetric system, while the correlated color temperature(CCT) was calculated based on CIE 1960 UCS diagram. The color rendering characteristics were evaluated according to the CIE Color Rendering Index (CRI), using Ra, Ri and ${\bigtriangleup}E$ from the 14 color samples defined in CIE13.3.

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The optical characteristics of White LED BLU with tunable chromaticity coordinates

  • Park, D.S.;Park, K.D.;Bae, K.W.;Kim, K.H.;Lim, Y.J.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07b
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    • pp.1507-1509
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    • 2005
  • LCD(Liquid Crystal Display) products is needed to have high reliability and are produced without harmful material. Because Substitution for CCFL of Light source used to Conventional backlight unit, research is going about product with LED of light source at present. In this experiment, We made the LED backlight unit with high quality for automotivenavigation. This backlight unit has center luminance of 6500 nit at15W power consumption. We adjusted chromaticity by using ten Blue LED and eight side emitting type White LEDs with high power LED from Lumileds company.

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Effect of Wavelength-dependent Scattering on the Color Chromaticity of the LCD Backlight

  • Kwon, Jin Hyuk;Jun, Hwa Joon;Gwag, Jin Seog;Lee, Hong Su
    • Journal of the Optical Society of Korea
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    • v.17 no.3
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    • pp.275-278
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    • 2013
  • The effect of the wavelength-dependent scattering on the change of the color chromaticity in the lightguide panel of a liquid crystal display is examined. The white light emitted from the white LEDs located at the edge of the lightguide propagates in the lightguide and is scattered by the patterned dots that are placed on the bottom of the lightguide. The scattered lights that are far from the LEDs showed reddish color compared to the bluish color that is scattered from the near area from the LEDs. The color difference was between 0.01 to 0.06 depending on the resin and the thickness of the lightguide.

Fabrication and Characteristics of Bioceramics for Artificial Dental Crowns (II) Mechanical Characteristics, Color and Color difference (인공치용 바이오 세라믹스의 제조 및 특성(II) 기계적 특성과 색도 및 색차변화)

  • 고영호;한복섭;이준희
    • Journal of the Korean Ceramic Society
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    • v.32 no.10
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    • pp.1203-1211
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    • 1995
  • The tests of three point bending and vickers hardness have been carried out to investigate mechanical characteristics of bioceramics for artificial dental crowns. And color and color difference test has been performed to study chromaticity changes after sintering specimens composited with glass and leucite powders. In addition, thermal dilation test has been carried out to examine bonding relations between dental porcelain and metal frame (Ni-Cr alloy). The result of three point bending test showed a maximum strength of about 68 MPa. Thermal expansion coefficient changed from 8.3$\times$10-6/$^{\circ}C$ to 13.5$\times$10-6/$^{\circ}C$ with increasing leucite content (0~30wt.%) in glass matrix. Bonding between porcelain (25% leucite-75% glass) and Ni-Cr alloy was excellent.

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Quality Characteristics of Jeung-pyun Added with Purple Sweet Potato (자색고구마를 첨가한 증편의 품질특성 및 기호도 분석)

  • Choi, Eunsil;Chung, Lana
    • Journal of the Korean Society of Food Culture
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    • v.32 no.4
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    • pp.323-331
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    • 2017
  • This study examined the quality characteristics of Jeung-pyeon made with wet non-glutinous rice flour and rice wine. The samples of Jeung-pyeon were prepared with different ratios of cooked purple sweet potato (0, 3, 6, 9, and 12%) to analyze the water content, sugar content, pH, chromaticity, texture characteristics, and sensory evaluation. No significant difference in water content, sugar content, and springiness was observed among the 5 samples. The pH and volume showed the highest level at 0%. The L-value and b-value decreased while the a-value increased. The hardness, chewiness, and gumminess were highest at 9% and lowest at 12%. The extent of violet chromaticity and pore size were optimal in 9%. In addition, 9%-added purple sweet potato showed the highest score of odor, taste, texture, and overall acceptability. In conclusion, the optimal addition for the highest acceptability of cooked purple sweet potato was 9%.

Synthesis and Optical Characteristics of Green-Emitting (Mg,Zn)$Al_2O_4:Mn^{2+}$ Phosphor for 3D- PDP Applications

  • Han, Bo-Yong;Yoo, Jae-Soo;Heo, Eun-Gi;Yoo, Young-Gil
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.272-275
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    • 2009
  • A new green phosphor, ($Mg_{1-x-yZnx)$)$Al_2O_4:Mn^{2+}{_y}$ (0 x 0.6, 0.001 y 0.01), was synthesized by a flux-assisted solid reaction and its vacuum ultraviolet (VUV) excitation and emission characteristics were examined in this study. The chromaticity and peak intensity of the $(Mg_{0.79}Zn_{0.2})Al_2O_4:Mn^{2+}{_{0.01}}$ (x = 0.177, y = 0.745) phosphor were found to be more desirable than that of $Zn_2SiO_4:Mn^{2+}$ (x = 0.216, y = 0.72) phosphor as a green primary color.

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Characteristics of Hybrid-type Transparent Electrodes Fabricated by Coating Carbon Nanotubes with Conductive Polymers (탄소나노튜브 위에 전도성 고분자가 코팅된 하이브리드형 투명전극의 특성)

  • Park, Jin-Seok;Park, Jong-Seol;Kim, Bu-Jong
    • Journal of the Semiconductor & Display Technology
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    • v.18 no.3
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    • pp.36-41
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    • 2019
  • Hybrid-type transparent electrodes were fabricated by depositing carbon nanotubes (CNTs) via spray coating on polyethylene terephthalate (PET) substrates and then coating the CNTs with [poly(3,4-ethylenedioxythiophene)] (PEDOT) films via electro-polymerization. For all of the fabricated electrodes, their surface morphologies, electric sheet resistances, visible transmittances, and color properties (e.g., yellowness) were characterized as functions of the applied voltages and process times used in electro-polymerization. The sheet resistance of the CNTs was significantly reduced by the coating of PEDOT, while their visible transmittances slightly decreased. The yellowness values of the PEDOT-coated CNTs were observed to have substantially decreased via electro-polymerization. The experimental results confirmed that the fabricated hybrid electrodes had desirable properties for the application of transparent electrode in terms of the electrical resistance, optical transmittance, and chromaticity.