• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.548-549
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• 2010

LED의 조도제어 방식은 타 방식에 비해 비교적 광색의 변화가 작고, 선형적인 조도제어가 가능한 PWM 방식을 사용한다. 본 논문은 LED를 PWM 방식으로 조도제어 했을 때, PWM 주파수에 의해 변화 하는 LED의 특성변화를 최소화하도록 주파수를 선택하는 방법을 제안하였으며, 이를 실험적으로 검증하였다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.12
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• pp.1-9
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• 2008

This paper is about l00[W] discrete LED floodlight lighting system, light color and color temperature to be controlled using the 3[W] RGBA LED, is developed the product with optical, heat dissipation, circuit, luminaire and system design. The result, color temperature is changed corresponding to black body locus from 2,000[K] to 10,000[K] and The Color Rendering Index(C.R.I) is achieved from 71 to 91 by high C.RI. Driving voltage is $90{\sim}250[Vac]$, circuit efficiency is 87[%], P.F is more than 93. moreover the LED lens is designed to achieve narrow, middle, wide beam angle, heat dissipation design is executed to minimize variation of luminous output by the surroundings temperature and to ensure reliability.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1999.11a
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• pp.213-216
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• 1999

빛의 3원색 Red, Green, Blue를 조합하여 분광조성을 달리하면 원하는 광색을 낼 수 있다. 이를 하나의 광원 형태로 개발하면 응용의 폭이 넓다는 장점을 지닌다. 현재 개발된 LED와 마이크로프로세서 기술은 이와 같은 가변색 광원을 만들기에 가장 적당한 것들이라고 판단하여 LED를 이용한 가변색 광원을 연구, 시제품을 제작하였다. 그리고, 개발된 가변색 광원의 응용분야와 가능성, 거기에서 파생될 수 있는 문제점을 분석하여 제시하였다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.95-100
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• 2007

Channel letter용 High Power LED Module 개발하기 위하여, 1W 백색(단색) LED 1EA LED Module과 1W 백색(단색) LED 3EA LED Module, 3W RGB LED 1EA LED Module에 대한 3종의 제품 개발하고, 고효율 RGB LED SMPS 회로 설계, 광색 가변을 위한 RGB LED 최적 배치 및 렌즈 설계, 고출력 1W LED Module 방열 설계 및 기구 개발, SMPS 회로 및 RGB LED 배열 회로 통합 시제품 직접 제작하였다, 신뢰성 평가 및 성능 시험 등을 실시하였으며, T자형 Channel letter에 기존 고휘도 LED Module과 개발된 고출력 LED Nodule을 동시에 적용한 결과, 기존 고휘도 LED Module를 사용하였을 경우에는 $1W{\times}10$개로 10W의 전력을 소비하였으나 개발된 고출력 LED Nodule은 $3W{\times}3$개로 9W의 전력을 소비하였으며 1W의 에너지가 절감되었음에도 불구하고 평균 휘도는 약 2.5배, 균제도는 1.43 배가 더 우수한 결과를 얻었다.

• Journal of The Korea Institute of Healthcare Architecture
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• v.29 no.3
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• pp.29-36
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• 2023

Purpose: The purpose of this study is to find out whether the color change of the LED light source has a significant effect on the beta wave activity of EEG in the learning state. Methods: The subjects of the experiment were 20 male and female college students between the ages of 19 and 25 who routinely perform their studies. In the created learning environment, the EEG change according to the change in the lighting color was measured while solving the Mensa thinking ability problem while sitting on a desk with LED lights installed on the top and a chair with a footrest to stabilize the legs. The light source consisted of 3 ready-made colors and 6 newly created colors. A total of 9 color light stimuli were given for 2 minutes each, and the EEG change of the subject was observed. After the experiment, the correlation was analyzed based on the mid-beta wave data recorded on the QEEG according to the color change of light and the Mensa problem score. Results: It was found that the activation of mid-beta waves was stimulated in the temporal lobes (T5, T3, T6, T4) and occipital lobes (O1, O2) of all subjects who focused on solving Mensa thinking problems. As a result of comparing the top 20% and the bottom 20% of problem solving scores, the upper group had no effect of lighting, while the lower group showed increased beta wave activity in response to color light stimulation in the order of T4, T6, and T5. Implications: It was confirmed that the color of light that activates the middle beta wave varies greatly depending on the subject's attention and learning ability, and it is judged that the color of light including the green wavelength is helpful in activating the middle beta wave in the group with low learning ability.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.1
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• pp.18-29
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• 2011

Light emitting diode(LED) technology has been increasingly developed and larger color gamut by LED illuminations can be reproduced; therefore more efficient LED lighting design can be accomplished under a consideration of color emotion. Fifty-two LED colors which are uniformly distributed on the uniform chromaticity space are evaluated in terms of fatigueness and preference and their relation to three color-appearance attributes(lightness, chroma and hue) are investigated. As a result, 23 human observers likely to prefer and feel comfortable, when lightness of a given LED color stimulus increases as well as its chroma decreases. The highest fatigueness score is observed in red color series and the most preferred LED color is found in green color series. In addition, fatigueness and preference show a strong negative linear relation and their Pearson correlation is higher than -0.8.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.1
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• pp.1-8
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• 2011

In this paper, the method to calculate chromaticity coordinate from spectral power distribution of LED is presented. Also, inverse tri-stimulus algorithm to find mixed luminance of red, green, blue LED from targeted luminance and chromaticity coordinate is proposed. Besides, digital light color control system of LED lamp applied this algorithm has been developed. In experiments, each chromaticity coordinate of red, green, blue LED calculated from this algorithm has relative percentage error of few % to measured values. Digital code is drawn from inverse tri-stimulus algorithm, and measured values of luminance and chromaticity coordinate of LED lamp digitally controlled by this code also have relative percentage error within a few % to targeted luminance and chromaticity coordinate.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.71-76
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• 2007

본 논문에서는 고 연색성의 실시간으로 색온도 제어 가능한 승강기용 조명제품 개발을 위하여 제품에 사용될 LED Package를 제작하고 고연색성 실현을 위한 색온도 제어 기초실험을 행하였다. 그리고 20W 급의 LED 광원모듈 구동회로와 색온도 제어를 위한 제어회로를 설계하였다. 또한 음영 제거 및 글레어 차단, 효과적인 광색혼합을 위하여 확산배광을 달성하기 위한 R, G, B, A, W LED의 최적 배치 및 렌즈의 광학설계를 수행하였고 LED에서 발생하는 열을 효과적으로 발산하여 LED 조명모듈의 온도를 낮추기 위한 방열설계를 실시하였다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.201-203
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• 2009

RGBY LED PKG를 이용하여 무대 사용을 위한 100W 급 LED 조명기구를 설계하고 무대에 적용하였을 때의 조명 환경을 예측, 분석 하였다. 이를 위하여 색온도 및 광색가변에 적합한 4 in 1 LED Package를 선정하고, 이를 이용하여 광원모듈을 구성하였으며, 또한 무대조명에 적용하기 위한 렌즈를 제작하였다. 이러한 LED 조명기구를 또한 무대조명에 적용하여 조명상황을 시뮬레이션 하고 무대 또는 객석에서의 평균조도 및 조도균제도 등을 계산하였다.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.8
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• pp.390-396
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• 2002

This paper Presents to choose number of RGB LED through optical special quality analysis of RGB LED samples and to produce ratio of RGB LED for a stable color variation and white light. Also, it is to design of a simple switching circuit using some resistances and switching transistors that is able to operate each 16 RGB LED stably, and switching control circuit base on a microcontroller that would be suitable for colors variation patterns control more than about 64 patterns and colors variation more than about 100,000 colors using ON/OFF and Duty control.