• 대한전자공학회논문지SP
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• 제42권4호
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• pp.31-38
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• 2005

본 논문에서는 동일 광원에서 휘도 변화에 따른 색 순응 현상을 고려하여 원 피사체와 동일하게 보이는 대응색을 재현할 수 있는 색 순응 모델을 제안한다. 제안한 CAM$\Delta$Y는 저휘도 상태의 시험 색과 동일하게 보이는 고휘도의 상태의 대응색으로 변환하는 변환 행렬로 모델링하고, 제안 모델의 최적 계수 값들은 Breneman이 실험한 주위 휘도별 대응색 데이터들로부터 구한다. 제안한 색 순응 모델인 CAM$\Delta$Y에 의한 예측 대응색과 Breneman의 실험 데이터 간의 측색적 좌표 오차 $\Delta$u'v'를 비교해 본 결과, Breneman의 D55 광원의 세 가지 서로 다른 밝기에 대한 실험의 대응색과 제안한 모델에 의해 예측된 색과의 평균 측색적 좌표 에러 $\Delta$u'w'의 값이 0.004 정도로, 이는 제안 모델의 평균 측색적 좌표 오차가 인접한 (adjacent) 두 컬러 샘플간의 구별 색차 정도로 아주 작은 오차를 가짐으로 그 성능이 매우 좋음을 확인하였다. 또한 제안한 CAM$\Delta$Y를 이용하여 동일 광원의 밝기에 따른 동일한 백색으로 보이는 등백색 상관 색온도 곡선 (equal-whiteness CCT curve, EWC)을 제안한다. 제안한 둥백색 상관 색온도 곡선은 이제까지 TV 제조 업자들의 경험에 의해 결정된 디스플레이 장치의 기준 백색을 설정하는 정량적인 기준으로 사용될 수 있다

• 조명전기설비학회논문지
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• 제26권12호
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• pp.1-8
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• 2012

The performance and lighting characteristics of the LED depend on cooling condition because the power LED generates lots of heat. In this paper, the effect of the generated heat from power LED module on lighting characteristics and performance is measured and evaluated. For experiments, the transient temperature of a power LED module with cooling condition is measured. In addition, the temperature and lighting characteristics of the LED module are measured during the steady state. As a result, the cooling condition is less effective on the lighting characteristics of the LED module at rated current but the cooling condition extremely affects those of the LED module over the rated current. Because high temperature of the power LED module causes the low phosphor conversion, luminance efficiency becomes low and color temperature becomes high. When power LED module are driven over the rated condition, higher temperature is directly related to lighting characteristics and performance of the LED module rather than higher current.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.476-481
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• 2009

In this paper, we propose a visible light road-to-vehicle communication system at intersection as one of ITS technique. In this system, the communication between vehicle and a LED traffic light is approached using LED traffic light as the transmitter, and on-vehicle high-speed camera as the receiver. The LEDs in the transmitter are emitted with 500Hz and those emitting LEDs are captured by a high-speed camera for making communication. The images from the high-speed camera are processed to get luminance value of each LED in the transmitter. For this purpose, first transmitter should be found, then it should be tracked for each frame, and the luminance value of each LED in the transmitter should be captured. In our previous work, transmitter was found by getting the subtraction of two consecutive frames. In this paper, we mainly introduce an algorithm to detect the found transmitter in consecutive frames. Experimental results using appropriate images showed the effectiveness of the proposal

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 E
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• pp.1770-1772
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• 1998

This study is concluded under by investigation about the lighting environment on a blackboard in elementary, middle, high school of inchon metropolitan. 1. The illumination was approximated to standard value in the side of quantity by the result of the Mimistry of Education's command. However, the uniformity of illuminescence was relatively increased. 2. In order to raise the blackboard lighting, we installed local lighting fixture for blackboard but most of schools are directly adopted to the way of sticking to the blackboard and the lower part of the blackboard is not effective. So that it is desirable of teacher and students to put the local lighting in front of the higher part of the blackboard or install in setting the perfect diffusion light from the ceiling. 3. Deviation of luminance is also more groat when local lighting exist for blackboard. And, regardless of local lighting, luminance of blackboard in side of window, from direction of floor is high because of regular reflected light. Therefore a curtain or blind must be installed pertinently.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.115-118
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• 2007

Luminous efficacy of 6.0 lm/W has been realized by introducing a spatial positive column discharge together with delayed D pulses, shared sustain pulse voltage, and low sustain frequency drive. Also a high speed addressing of $0.25{\mu}s$ was achieved. The luminance was $157cd/m^2$, which is high enough for a 260-in. FHD display.

• 대한전자공학회논문지SP
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• 제45권4호
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• pp.50-58
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• 2008

본 논문에서는 대역 제한된 색도 신호에 의해 발생하는 색 번짐 현상을 TV 수신단이나 MPEG 디코더에서 효과적으로 개서하는 색 버짐 개선 방법을 제안한다. 비디오 영상 신호는 영상의 밝기 정보를 가지고 있는 한 개의 휘도 신호와 색상 정보를 가지고 있는 두 개의 색도 신호로 구성되어 있으며 사람의 눈이 미세한 면적에 대해서는 색의 변화를 거의 인식하지 못하는 점을 이용하여 색도 신호의 고주파 정보를 제한하고 있다. 하지만 HDTV와 같은 고화질 화상 제품이 생산됨에 따라 색 번짐 현상이 화질 저하의 요인으로 인식되기 시작하였다. 본 논문에서는 영상 융합 기술을 이용하여 색도 신호보다 더 많은 고주파 정보를 가지고 있는 휘도 신호의 고주파 성분을 이용하여 손상된 색도 신호의 고주파 성분을 추정하는 방법을 제안한다. 휘도 신호로부터 추출된 고주파 성분은 추정된 색도 신호와 원본 색도 신호 사이에 발생하는 에러의 ${\iota}_2-norm$이 최소화 되도록 설계된 공간 적응적 가중치에 의해서 적절히 조절된 후에 입력 색도 신호와 결합되어 색 번짐이 개선된 색도 신호를 얻을 수 있게 하다. 제안하는 색 번짐 개선 방법은 색도 신호의 해상도를 휘도 신호의 해상도만큼 향상시키기 때문에 자연스러운 결과를 출력하며 또한 기존의 방법에서는 개선하기 힘들었던 좁은 경계에서의 색 번짐 현상도 효과적으로 개선한다. 실험 결과에서는 제안된 방법이 기존의 방법에 비해 시각적 및 수치적인 면에서 뛰어난 결과를 보임을 확인할 수 있다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.339-342
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• 2003

Main PDP panel efficacy improvement factors are discussed. A large panel efficacy improvement can be obtained through a combination of discharge efficiency improvement and phosphor improvement. Important design elements are a high Xe-content gas mixture, the application of a $TiO_2-layer$, and a new green phosphor with little saturation at high VUV-load. In a 4-inch color test panel with a conventional stripe-type cell configuration a white efficacy of 4.4 lm/W and a luminance of 5000 $cd/m^2$ is obtained for sustaining at 250V in addressed condition.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.612-615
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• 2004

We present an extremely high efficient red organic light-emitting diodes (OLEDs) using a fluorescent dye 4-(dicyanomethylene)-2-tert-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) doped into an emitting region which consists of multiple pairs of a doped and an undoped layer. An emitting region of OLEDs composes of a tris-(8-hydroxyquinolinato) aluminum (Alq3) codoped with rubrene of 5% wt. or a mixture of Alq3 and rubrene (1:1). The luminance yield of the codoped device and the mixed device are 6.5 cd/A and 9.2 cd/A at 10 mA/$cm^2$, respectively. We have considerably improved the luminance yields of red OLEDs as much as ${\sim}$90% at 10 mA/$cm^2$ compared with that of the device doped with only DCJTB. We attribute it to both the emitting assist dopant (rubrene) and the dotted-line doping structure in an emitting region of OLED.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권6호
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• pp.261-266
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• 2003

We investigated the effect of oxygen plasma treatment of indium-tin oxide(ITO) surface on the performance of electroluminescence(EL) devices. ITO surface treated oxygen plasma has been analyzed using atomic force microscope(AFM) and X-ray photoelectron spectroscopy(XPS), to investigate the relations between the properties of the ITO surface and the properties of the current-voltage-luminance(I-V-L) characteristics of the fabricated OLED with the structure of ITO(plasma treatment) / TPD / Alq$_3$/ Al. It is found that the oxygen plasma treatment of ITO anode improve the hole injection of the OLED due to the modification of the surface states. The treated ITO anode nay be low voltage with high luminance efficiency.

• 소성∙가공
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• 제19권8호
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• pp.474-479
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• 2010

Newly suggested hybrid LED package can reduce the number of LED processes and enhance light efficacy in virtue of its integrated optical patterns. Square-type pyramid pattern was chosen for the integrated optical pattern in this study, and it was proved that the pattern enhances illuminance about three times and luminance about two and half times by optical simulation. Square-type pyramid patterns of 0.02mm height and 0.04mm pitch were successively machined on a copper mold which is necessary for imprinting the integrated pattern. Hybrid LED package with integrated optical pattern will be manufactured with ultra-fine machined mold in future study.