• Journal of the Optical Society of Korea
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• v.11 no.2
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• pp.67-70
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• 2007

A Wide Color Gamut Backlight system was studied using a three-band white Light-Emitting Diode. A three-band white light-emitting diode (LED) was fabricated using an InGaN-based blue LED chip that emits 445-nm blue peak, and a green phosphor and red phosphor that emit 535-nm green and 621-nm red peak emissions, respectively, when excited by 450-nm blue light. Using for this three-band white LED, wide color gamut backlight unit (BLU) was attained. The luminance of BLU and CIE 1931 chromaticity coordinates was $1,700Cd/m^2$ and (0.337, 0.346). Color filter matching simulations for this configuration show that the three-band white LED backlight can be enhanced by up to 16% over conventional white LED backlight color gamut.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.2 s.302
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• pp.69-80
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• 2005

In these days, the technology development of the imaging/optic industry and the digital broadcasting replace the classic CRT with the new display devices that is getting slimmer and larger. Especially, when the general TV signal is applied directly to the wide gamut display using LED or laser, which can display higher chromatic colors that can't be reproduced on CRT, the color distortion occurs and it causes serious problems. Thus, in this paper the gamut mapping is studied, which gets rids of the color distortion and utilizes the wider color gamut than that of the CRT sufficiently. In the gamut mapping the general mapping concept is the increasement of the chroma on the same hue plane but it causes the over chromatic enhancement. So, the vector mapping, which increases the lightness md the chroma at the same time, is proposed to prevent the side effect. In the vector mapping the chromaticity is maintained constantly, hence the image can be seen more natural than that of the chroma mapping. By using the gamut fitting, it is compensated that the tone disappearance or the contour effect that is arose from the geometric properties of the input and the output color gamut. These gamut mapping and gamut fitting can prevent the color distortion and reproduce the natural image on the wide gamut displays.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1377-1380
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• 2008

A development of low power display is an important problem from a point of reduction in worldwide energy consumption. In this research, we aimed to achieve a high quality and low power paper-like reflective full-color display and investigated the design rules for the light diffusing film, LC-cell structure, front lighting systems based on the diffused light control technology. As a result, we successfully obtained the high quality reflective liquid crystal display with a high reflectivity, a wide color gamut and a high motion picture quality.

• Proceedings of the IEEK Conference
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• 2003.07e
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• pp.1755-1758
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• 2003

색 재현 범위(Color Gamut)가 기존의 표준신호(예 sRGB, Rec. 709)대비 상이한 Laser 디스플레이 장치에서 Gamut Matching Algorithm을 이용하여 표준 컬러의 재현을 가능하게 하고, CRT 대비 광범위한 Laser Color Gamut 의 모든 색 영역을 표현 할 수 있다. 이 방법은 일정한 휘도 및 hue 에서 표준입력과 출력장치의 색 재현 범위에 따라 주어진 입력신호의 Chroma를 늘이거나, 줄임으로써 출력장치의 전 색 재현 범위를 사용할 수 있게 된다.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1327-1330
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• 2008

A novel fiber optic solution is provided to efficiently mix visible colors. Full color synthesis was achieved utilizing a novel $3{\times}1$ hard polymer clad fiber (HPCF) coupler along with red, green and blue (RGB) light emitting diode (LED) primaries. Varying the intensities of RGB LEDs that are coupled to three input ports, the device rendered a full color with an ultra wide CIE color gamut. Potential applications in pica-projection displays and LED backlights will be discussed.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1086-1089
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• 2006

We have developed 2.4" QVGA wide color gamut LCD module using RGB-LED backlight. The color gamut is achieved 100% of NTSC compared to 70% of NTSC when used with White-LED backlight. But RGB LED backlight is difficult to maintain its color balance since RGB LED is gradually degraded by the change of ambient temperature and a long term aging characteristic, etc. This paper describes a feasibility study of our optical feedback system developed for preventing such a color shift.

• Current Optics and Photonics
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• v.3 no.6
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• pp.590-596
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• 2019

To improve the color gamut of a liquid-crystal display (LCD), we propose a bandpass filter that is added to the backlight unit to optimize the backlight spectrum. The bandpass filter can only transmit red, green and blue light in the visible range, while reflecting the unwanted light. We study the optical properties of the bandpass filter using the transfer-matrix method, and the effect of the bandpass filter on the color gamuts of LCDs is also investigated. When a bandpass filter based on a 5-layer configuration comprising low and high refractive indices ((HL)²H) is used in phosphor-converted white-light-emitting diode (pc-WLED), K₂SiF₆:Mn⁴⁺ (KSF-LED), and quantum-dot (QD) backlights, the color gamuts of the LCDs improve from 72% to 95.3% of NTSC, from 92% to 106.7% of NTSC, and from 104.3% to 112.2% of NTSC respectively. When the incident angle of light increases to 30°, the color gamuts of LCDs with pc-WLED and KSF-LED backlights decrease by 2.9% and 1% respectively. For the QD backlight, the color gamut almost does not change. When the (HL)²H structure is coated on the diffusion film, the color gamut can be improved to 92.6% of NTSC (pc-WLED), 105.6% of NTSC (KSF-LED), and 111.9% of NTSC (QD). The diffusion film has no obvious effect on the color gamut. The results have an important potential application in wide-color-gamut LCDs.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.245-248
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• 2007

We report a novel optical structure for bottomemitting white OLEDs. The structure includes, reformulated color filter, dielectric mirror to enforce cavity resonance, and micro-scatterer to extract more light and diffuse the viewing angle dependency. With the new structure, the color gamut was 104% of that of NTSC, the combined transmission efficiency of the color filter was 83%/3 and the color shift at $45^{\circ}$ was maintained below 0.02 in the 1976 CIE color space. The color performance of White OLED + color filter system can match comparably that of RGB OLED + microcavity system.

• Information Display
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• v.19 no.6
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• pp.18-23
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• 2018

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1112-1115
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• 2008

A very high current efficiency of 28 cd/A for three-mode microcavity tandem WOLED was successfully demonstrated. The 101 % of NTSCu'v' ratio of this white OLED with LCD color filter was achieved. In addition to wide color gamut, the highest delta (u'v') of respective RGB colors among the viewing angles 0 and 60 degree is just 0.042 and that of white color is less than 0.02.