• Journal of Information Display
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• v.10 no.4
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• pp.164-170
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• 2009

The dependences of color gamut size and power consumption on the area ratio of the neutral and green subpixels for the RGB-LED-backlight RGBW LCD were studied, in which the red- and blue-subpixel areas are the same and represent one-quarter of the pixel aperture area. It was found that the color saturation of the RGBW LCD can be improved through the use of a smaller neutral- and green-subpixel area ratio, at the expense of higher power consumption.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1073-1076
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• 2009

The dependences of color gamut size and power consumption on the area ratio of neutral and green sub-pixels for the RGBW LCD with RGB LED backlit are studied, in which the areas of red and blue sub-pixels are the same and are one quarter of pixel apertu re area. It is found that high color saturation and power saving can be achieved for the proposed RGBW LCD.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.5
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• pp.696-704
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• 2013

In this paper, we introduce the LED emotional lighting system realized with the aid of both intelligent algorithm and RGB LED combined with White LED. Generally, the illumination is known as a design factor to form the living place that affects human's emotion and action in the light- space as well as the purpose to light up the specific space. The LED emotional lighting system that can express emotional atmosphere as well as control the quantity of light is designed by using both RGB LED to form the emotional mood and W LED to get sufficient amount of light. RBFNNs is used as the intelligent algorithm and the network model designed with the aid of LED control parameters (viz. color coordinates (x and y) related to color temperature, and lux as inputs, RGBW current as output) plays an important role to build up the LED emotional lighting system for obtaining appropriate color space. Unlike conventional RBFNNs, Fuzzy C-Means(FCM) clustering method is used to obtain the fitness values of the receptive function, and the connection weights of the consequence part of networks are expressed by polynomial functions. Also, the parameters of RBFNN model are optimized by using PSO(Particle Swarm Optimization). The proposed LED emotional lighting can save the energy by using the LED light source and improve the ability to work as well as to learn by making an adequate mood under diverse surrounding conditions.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.6
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• pp.706-713
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• 2020

To control the LED lighting for broadcasting, LED current control using tri-stimulus values is used for RGB LEDs. For the convenience of control, this control is approximated as a linear function or used as an appropriate value through trial and error. Also, it is not suitable for broadcast lighting because it does not use a diffuser plate applied for mixing sufficient light and color required for actual it. In this study, a neural network with excellent nonlinear function approximation is used as a control method for LED panels for broadcast lighting. We intend to implement an LED panels controller suitable for the desired chromaticity coordinates and dimming values of intensity. As a result of the performance evaluation, the errors of the xy chromaticity coordinates are mostly ±0.02 and the acceptable range of ANSI C78.377A was satisfied. The average errors of the xy chromaticity coordinate are xerror=0.0044 and yerror=0.0030, respectively, and we confirmed the superiority and stable performance of the proposed algorithm.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.12
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• pp.10-22
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• 2009

This paper presents an LED lighting system with an LED color control algorithm that can independently change its color temperature and illuminance. To show the validity of the proposed algorithm, it is proven that its solution always exists. The proposed algorithm was applied to the control of an LED module that is composed of red, green, blue, and white (RGBW) LEDs. Its color temperature variation ranged from 3,500~7,500[$^{\circ}K$], and its illuminance ranges from 500~1,500[lux]. Within these range, the color temperature and illuminance deviations are as low as $\pm0.8$[%] when the junction temperature of LEDs are maintained at 40[$^{\circ}C$]. In the range of 30~70[$^{\circ}C$], the measured illuminance and color temperature deviations are as low as 2.1[%] and 3.6[%], and the compensated ones are as low as 1[%] and 0.49[%], when the desired illuminance and color temperature are 1,000[lux] and 6,500[$^{\circ}K$], respectively.nyang.ac.kr).

• Journal of Industrial Technology
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• v.31 no.A
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• pp.95-101
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• 2011

According to recent technological developments in high-power LEDs, the stage lighting is one of most important areas to apply power LED system. Moving light for color rendering of stage uses the RGBW(red, green, blue, white) color mixing method. LED moving light system needs to have a wide range of dimming control as enough to operate at very low power. Also LED dimming system should not be induced color-shift and flicker in camera. This paper is experimentally verified the LED Moving Light driving circuit of 200Watt level designed to satisfy the above characteristics which applied the DC current-controlled and PWM mixed dimming method.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.546-547
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• 2010

최근 고출력 LED의 기술적 진보에 따라 여러 분야에서 LED의 적용 시도가 확산되고 있다. 그 중 LED 무대조명은 조도 제어범위가 넓어 매우 낮은 전력에서 LED를 정전류로 구동할 필요가 있다. 본 논문에서는 200Watt급 RGBW Moving Light를 매우 낮은 전력까지 구동하기 위하여 DC 전류제어 디밍 방식을 적용하였으며, 이를 위한 회로를 설계하여 이를 실험적으로 검증하였다.

• 한국태양에너지학회:학술대회논문집
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• 2011.04a
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• pp.168-173
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• 2011

Recently, from a saving energy and environmental lighting sources point of view, using LED lighting have been increased rapidly. The colors of light was applied to the control of dimmers that is composed of red, green, blue, and white(RGBW) to improve the quality of visual environment. Moreover this study has been processed to develop adjustable dynamic LED lighting system on SPD and definitize the various spectral power distribution and color temperature of light through the control of the four dimmers. It is possible to combine up to $432^4$ kinds of light. Measurement of illuminance of range on working surface was as 7~l,831 lux. Application of visual environment for occupants can be expected according to control of lighting performance.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.3
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• pp.359-364
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• 2011

The study uses department of the sensitivity and fuzzy reasoning, one of artificial intelligence algorithms, so that develop LED lighting system based on fuzzy reasoning for systematical control of the LED color temperature. In the area of sensitivity engineering, by considering the relation between color and emotion expressed as an adjective word, the corresponding sensitivity word can be determined, By taking into consideration the relation between the brain wave measured from the human brain and the color temperature, the preferred lesson subject can be determined. From the decision of the sensitivity word and the lesson subject, we adjust the color temperature of RGB (Red, Green, Blue) LED. In addition, by using the information of the latitude and the longitude from GPS(Global Positioning System), we can calculate the on-line moving altitude of sun. By using the sensor information of both temperature and humidity, we can calculate the discomfort index. By considering the altitude of sun as well as the value of the discomfort index, the illumination of W(white) LED and the color temperature of RGB LED can be determined. The (LED) sensitivity lighting control system is bulit up by considering the sensitivity word, the lesson subject, the altitude of sun, and the discomfort index The developed sensitivity lighting control system leads to more suitable atmosphere and also the enhancement of the efficiency of lesson subjects as well as business affairs.

• Proceedings of the KIEE Conference
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• 2008.10c
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• pp.120-122
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• 2008

This paper presents a color control algorithm for LED lights with independently changable illuminance. The proposed algorithm adjusts the light intensity to obtain a desired color with alterable illuminance To verify the validity of the proposed algorithm, it was applied to control of a RGBW LED module. The achieved color temperature range of the module was from 3000K to 7500K, and the illumination one was from 500 lux to 1500 lux.