• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.1
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• pp.66-74
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• 2013

This paper introduces the improvement of QoS to compensate the decreasing LED performance by temperature characteristic in the LED-ID communication system. LED does not only use as a lighting device, but also uses as a communication device. The conventional system is transmitted by RGB of LED following the mixture color ratio, which determined the color of lighting, and the BER performance of each RGB signals. However, when the LED used consistently, it has occurred the heat temperature. As a result, LED is degraded the performance by increased temperature each device. To solve this problem, we proposed the adaptive modulation and coding scheme by temperature of device to improve the performance of system and satisfied the QoS in the LED-ID system.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.12
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• pp.23-30
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• 2009

LEDs are increasingly used for many applications including automotive, aviation, display, transportation and special lighting applications. Generally, the RGB multichip LED luminaire applied to signboard, emotional lighting system and display device and the white LED luminaire applied to general lighting system. white LED spectra for general lighting should be designed for high luminous efficacy as well as good color rendering. This paper describes characteristics of LED luminaire white LED and RGB multichip LED. Two type of LED luminaire prototype used experiment physical, electrical and optic test and performance analyzed. RGB multi-chip and phosphor-type white LED luminaire were analyzed by experiment on their color characteristics and luminous efficacy of radiation, distribution curve, and electrical characteristics. Research work is in progress to develop an improved performance for optic and electrical works well for two type of LED luminaires.

• Journal of the Institute of Electronics and Information Engineers
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• v.54 no.6
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• pp.123-133
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• 2017

In this paper, we developed an optimal flicker-free control algorithm operating within 16 luminance implementation bits and 512 brightness implementation pulses irrespective of LPM(LED Pixel Matrix) module configuration on dynamic driving method of LED display system. As an implementation method, we turned the refresh rate up by increasing the number of scans through multiple shift-latches which were devised from conventional shift-latch scheme for full color representation. As a result, the LED display system of this method has no flicker phenomenon because of the novel refresh rate higher than 2,040[Hz] incomparable to 240~480[Hz] of conventional system.

• 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.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.3-6
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• 2008

The purpose of this study is to investigate the luminous environment of fluorescent lamp and LED lamp in a office space for various color temperature by subject response test. For this, three different color temperatures were tested for the same illuminance level. Based on such test results for various color temperatures of fluorescent lamp and white LEDs, this study is to analyze the preferences of color temperature and light source, and perceptional brightness of each light source and color temperature. Then, this study is to derive the guidelines for the performance of color temperature which are suitable on the purpose and the mood of a office space.

• Korean Journal of Materials Research
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• v.27 no.6
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• pp.312-317
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• 2017

In the construction of a white LED, the region of the red emission is a very important factor. Red light emitting materials play an important role in improving the color rendering index of commercial lighting. These materials also increase the color gamut of display products. Therefore, the development of novel phosphors with red emission and the study of color tuning are actively underway to improve product quality. In the present study, heuristic algorithms were used to search for phosphors capable of increasing the color rendering index and color gamut. Using a heuristic algorithm, the phosphors that were identified were $SrGe_4O_9:Mn^{4+}$ and $BaGe_4O_9:Mn^{4+}$. Emission spectra study confirmed that these phosphors emit light in the deep red wavelength region, which can fulfill the requirement for the improvement in color rendering index and color gamut for a white LED.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.4
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• pp.77-83
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• 2014

Visible light communication is a converging communication by technologies that enable solutions using the LED Lighting. There is a need to research about it in order to improve the performance of the wireless communication by using a Color LED and improve the efficiency of data. In this paper, Assume the General indoor communication environment and LED communication systems based on CSK-OFDM applied to a MIMO communication system, We studied about transmitting method of more efficient communication. After performing the simulation based on IEEE 802.15.7 Standardization, as a result of the analysis of performance, it was confirmed the there is a significant impact on the performance of SNR and BER performance by the transmitting method based on MIMO and external noise using the LED communication system based on CSK-OFDM.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.757-758
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• 2010

At the time of medical treatment and surgical operation, halogen lamp and plasma lamp were mainly used as luminous source for lighting. These two luminous sources have drawbacks that the life of lamps are not long, various problems are brought about due to excessive heat generation and its volume is very big because of cooling device. Accordingly, in this research a ring light was developed so that a partial shadowless shooting for the patient's affected area at the medical treatment room and surgical operation room using high luminance LED for which attention is being paid as new lighting parts for medical purpose. LED which was applied to the development used high luminance three color LED for full color for which various color materialization and the adjustment of radiation intensity are possible and we can get white light in order to emphasize the delicate expression for generic tone of shooting object, strong highlight, simple shadow and three dimensional effect at the time of close-up shadowless shooting of the affected area.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.2
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• pp.102-108
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• 2011

The existing vessels lighting control system has several problems, which are complexity of construction and high cost of establishment and maintenance. In this paper, We designed low cost and high performance lighting control system at digital vessel environment. We proposed a system which recognize the user's emotions after obtaining the biological informations about user's bio information(pulse sensor, blood pressure sensor, blood sugar sensor etc) through wireless sensors controls the LED Lights. This system classified emotions using backpropagation algorithm. We chose 3,000 data sets to train the backpropagation algorithm. As a result, obtained about 88.7% accuracy. And the classified emotions find the most appropriate point in the method of controlling the waves or frequencies to the red, green, blue LED Lamp comparing with the 20-color-emotion models in the HP's 'The meaning of color' and control the brightness or contrast of the LED Lamp. In this method, the system saved about 20% of the electricity consumed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.689-691
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• 2010

This study is the visually identification lighting for easy to distinguish using colors LED on AtoN facility in harbor gate, which have realized a controller for certainly express the gate of harbor by red light and green light of both sides a harbor and for synchronization at a time of right and left or sequential the harbor guidance light through synchronizer or timer by GPS. There is expectation effect that is prevent a confusion about distinguish of facility by ship's operator and to beautify a night scene of harbor, which is expressed to identification lighting differ from great many lighting of harbor with variable color lighting the lighthouse body and vertical layer color lighting using LED. Especially the function of AtoN is displayed for harbor safety message by CW lighting, and this system is the power consumption greatly reduce by candle alternated high light LED.