• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.1
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• pp.27-32
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• 2012

Since LED lights have advantages of long life, low-carbon and high efficiency, they have been widely used as household lamps, automotive lighting, traffic lights etc. In this study, MCPCB LED lamps for automotive LED headlights were manufactured and the performance of heat release was optimized. The developed LED headlight satisfied the target thermal performance with heat pipes and fans, and it was also shown that fan life can be prolonged three times by fan on-off control.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.10B
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• pp.1252-1257
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• 2011

In this paper, efficient functions for audio spectrum mapping with visible spectrum are proposed. Through mapping overall hearing frequency band with visible frequency band, emotional lighting might be possible. We propose a basic linear mapping function and non-linear mapping functions emphasizing specific audio frequency bands. For the algorithm implementation, spectrum analysis method and filter method are introduced. Especially, in this paper, a prototype LED lighting equipment using the digital filter method is implemented. The proposed lighting method can be applied to many LED lighting area using music.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.1
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• pp.64-70
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• 2011

This paper presents a zero-transient current control method for PWM dimming of LED. Since the proposed LED current control method has no transient state, it features a high resolution, high linearity, and no current overshoot through LED along a wide dimming range. The operational principles of the proposed LED current control circuit are presented. To confirm the validity of the proposed method experimental results from a prototype circuit of the 46-inch LCD TV are given.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.1
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• pp.111-116
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• 2015

In this study, the constant current converter for LED lighting was designed and the electrical characteristics of the fabricated SMPS was measured. When the output current is 300mA the maximum efficiency of 85% was shown and the output current is in the range of 100~400mA efficiency over 70% were exhibited. Also the dimming levels control over the range of 0 to 100% was possible by using a control signal of 0~250mV.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2295-2296
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• 2008

본 논문에서는 에너지 절감을 위하여 POWER LED 구동회로를 PIR(Pyroelectric Infrared Ray) 센서를 이용하여 ON/OFF 제어를 하였다. POWER LED의 전류 특성을 설명하였으며 설명된 전류 특성을 개선하고자 정전류 유지 회로를 구성하였다. 그리고 인체 감지 센서에서 발생되는 ON/OFF 신호를 증폭시키는 구동 회로를 설계하여 정전류 유지 회로에 직접 결합하는 방식을 제안하였다. 실험한 결과는 POWER LED의 ON 상태시 4Watt, OFF 상태시 0.5Watt를 소비하였으며, 정전류 유지 회로에 의해 POWER LED 구동 전류의 리플이 줄어들어 안정적인 동작을 하는 것으로 나타났다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.05a
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• pp.3-5
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• 2009

종래의 LED 휘도를 제어하는 방식은 PWM방식이 주로 사용되었다. PWM방식은 지극히 아날로그적인 방식으로 통신 등의 디지털 방식과는 호환이 어려운 단점을 가지고 있다. 본 논문에서는 디지털 방식으로 LED의 휘도를 제어하는 실험을 하였다. LED 구동회로와 디지털논리회로를 제작하여 임의의 디지털 값을 입력한 후 휘도와 CIE x,y좌표를 cs-200으로 측정하여 측정한 색의 x,y좌표가 원하는 색의 x,y좌표영역에 포함될 수 있도록 디지털 입력 값을 최적화시키는 실험을 진행하였다. 본 연구에서 얻은 결과 값을 통하여 디지털 제어로 LED의 휘도를 제어하여 풀 컬러 구현의 가능성을 분석하였다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.1
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• pp.115-122
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• 2012

In this paper, we demonstrate that indoor wireless optical communication is possible with lighting LEDs without a photo diode or a solar cell. A LED is used for both light emitting and light signal detection. This scheme is very useful because transmission is possible without any additional communication systems. In experiments, wireless optical communication will be carried out at a higher signal frequency of 5MHz using a lighting LEDs with both light emitting and light detection characteristics in the future.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.9
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• pp.1933-1940
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• 1997

The development of CMOS IC chip and external system with optical transmission sytem is proposed in this paper, which deal with 4 subject 4 channel biological signals, receive and transmit biological signals to the external system using LED and infrared light of photodiode. This system decreases the dependency of power supply voltage to the COMS IC chip. A newenforce synchronization technique using infrared bi-directional communication has ben proposed. The telemetner IC with the size of $5.1{\times}5.1mm^2$ has the followingfunctions:receiving of command signal, initialization of internal state of all functional blocks, decoding of subject selection signal, time division multiplexing of 4-channel modulated biological signals, transmission of modulated signals to external system, and auto power down control. To confirm the total telemetry system, electrocardogram is transmitted and received to the external system using optical link.

• Journal of Korea Multimedia Society
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• v.16 no.11
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• pp.1325-1337
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• 2013

Music affects sensitivity and emotion of human, emotional power of the music has been applied to various fields. Especially, to visualize as well as listen to music is able to create various atmosphere. In this paper, we proposed sensitivity control system for interaction with people to merge music and lighting. Because existing FT(Fourier Transform) has not information about the time, to analyze information of changed signal according to the time is difficult. In order to solve such a problem, we use STFT(Short Time Fourier Transform) method to analyze music signal. and also, we classified music for three genre and compared the frequency characteristics according to genre, and control the color, brightness of LED light based on the frequency components within analysis range. Unlike existing LED lighting control study using music, we had color control of emotional lighting and brightness control using variation amount of music signal in this paper. Proposed lighting control system will be able to utilize various industry fields as well as emotional lighting.

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.602-606
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• 2008

LCD is supplied light by BLU(Back Light Unit) and the light represents color by each color filter. Also LCD adjusts the amount of light by controlling liquid crystal between the glass of upper plate and one of lower. However, it is impossible to completely exclude light due to the structural and physical characteristic of liquid crystal. Therefore, on transfering light through optical sheet and liquid crystal, many problems are generated. They are related with energy efficiency and get effective for the contrast of LCD to have lower contrast ratio than other display devices. To solve the problems, many techniques have been studied and developed but don't exist keys to solution for them. Among methods, local dimming is one example to be applied to LCD. In this paper we propose image processing algorithm for local dimming of BLU of LED used as light source. The proposed algorithm extracts maximum luminance signal and lights using each extracted signal on segmented region of BLU. Also the proposed algorithm generates image signal in corresponding to luminance of the segmented region and supplies them with LCD panel to represent image with improving luminance ratio.