• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.1
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• pp.83-90
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• 2019

LED lighting is spreading on the strength of LED lighting, and various government policies are being implemented. VLC research which is a wireless communication technology using lighting has been actively conducted, and it has been proven through many studies that a general LED light source such as a high-speed data transmitter can be used. But from now on, one of the main problems is the noise from side lights, which can be compared to the noise of radio broadcasts. So in this paper, we proposed a noise canceling model to remove the interference of ambient light by using an optical filter for a detachable VLC channel. In order to verify the proposed model, various high brightness RGB LED modules were used for comparative analysis. In addition, the applicability was verified through experiments using High Luminance LED lighting which is applied in real life.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.2
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• pp.43-52
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• 2011

LED lighting may cause different sensation and color appearance due to the different spectral power distributions compared to those of conventional lightings. Particularly, the CCT (Correlated Color Temperature) of LED lighting has a major effect on color appearance so that this study conducted an experiment through a subjective evaluation and luminance measurement for effective color appearance in a space. This study performed a subjective evaluation under the seven different LED CCT conditions, and color appearance was evaluated with major five colors in a customized lighting box. In addition, luminance measurement was conducted for each CCT and color condition to compare the results from a subjective evaluation. The results of this study may help to select a proper LED CCT for specific color conditions.

• Journal of the Semiconductor & Display Technology
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• v.15 no.4
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• pp.79-85
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• 2016

For long life time and high efficiency, not necessary in improvement of LED chip structure, but also improve heat radiation for decrease heat in LED chip. In this study, efficiency decline factor has been investigated in LED lamp as study heat characteristic, luminance flux and heat resistance. When LED lamp temperature was increased, about 7% loss of luminance flux. In consequence of temperature analysis, width of fin was the most important factor of heat radiation. As a result, secure the enough heat path is very important factor of LED lamp design.

• Transactions of Materials Processing
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• v.19 no.8
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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.

• Journal of the Korean Society of Clothing and Textiles
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• v.41 no.2
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• pp.352-361
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• 2017

This study prepared 5 retroreflective fabrics of glass beads and colors of silver, gold and purple in order to characterize morphologies, luminance and illuminance properties. Retroreflective fabrics were prepared according to division and area by Samp.1 (Division 2, area $80cm^2$), Samp.2 (Division 2, area $60cm^2$), Samp.3(Division 3, area $60cm^2$), Samp.4 (Division 5, area $50cm^2$), and Samp.5 (Division 1, area $100cm^2$). The results of the morphologies indicate that the back side of retroreflective fabrics was the 3M-Sv, RF-Sv. The RF-Gd of the fabrics were woven fabrics and the SRF-Sv, SRF-Pp was knitting. The largest glass bead size was 3M-Sv and the smallest was SRF-Pp. RF-Sv was the thinnest and SRF-Sv, SRF-Pp were the thickest. The results of luminance properties indicated a tendency to decrease slightly as the number of divisions and area increased, except for Samp.2 to Samp.3. The result of illuminance properties tend to increase as the number of LED becomes greater than the number of divisions in the same area; in addition, the higher the luminance as a whole increases. The results show that it is preferable to use a silver-colored RF-Sv which has the highest luminance and physical properties when a retroreflective fabric is applied to clothes.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.12
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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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.429-429
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• 2007

In this study, it was investigated about the variation of luminance properties in LED backlight with geometrical shape such as prism or lens shape on the light-entering face. Generally, LED light source has the loss in backlight system because it has horizontal direction light. PMMA(Poly-Methyl-Meta-Acrylate) is used LGP(Light-Guide-Plate) in conventional backlight system. PMMA has low refraction angle. so that. horizontal direction light was not used in backlight system. The addition of geometrical shape in light-entering face in LGP improves the luminance characteristics because it prevents horizontal direction light generation in light-entering-face. Prism or lens shape in same pitch disposition was almost same without these treatment such as the value of 1% rising. Besides. It is particular that the gap of these shape such as the value of 0.407~0.22mm prevents horizontal direction light, so then it contributes luminance rising at 5.6%.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.69-72
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• 2009

Recently, LED(Light Emitting Diode) TV has attracted greate attention due to its super-slim form factore as well as low power consumption. LED TV is actually an LCD(Liquid Crystal Display) TV in which edge-lit LED backlight is adopted. In the presente study, we report on the comparison of optical characteristics 55-inch edge-lit LED backlight and CCFL(Cold Cathode Fluorescent Lam)backlight. The angular distribution of the luminance and the on-axis luminance gain on each optical component were investigated and compared. The effect of the backlight structure on the performance of the optical films was studied and discussed.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.9 no.3
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• pp.80-85
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• 2010

In this paper, we present an algorithm for efficient control of backlight LED in order to reduce the power consumption of LCD TV. In addition, a pragmatic implementation method is presented. In conventional local dimming control, backlight LEDs of LCD TV are divided into $M{\times}N$ blocks. And, the proper luminance for each block is computed according to input image and used for dimming control. But, LED light of each block is diffused and affects the neighboring blocks, so that luminance of each block becomes larger than that of intent. In the proposed algorithm, dimming control values are reduced by the amount of quantity affected by the neighboring blocks using light spread function, resulting in additional reduction of power consumption.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.1
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• pp.114-119
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• 2011

There is a limit to technology of improving luminous intensity uniformity and glare, known as a weakness of existing LED lamp. Because of Using many LED, LED lamp not only waste energy but have bad effect on efficiency. Our goal is to develop security lights solution which is contented with suitable area in KS(Korean Industrial Standards) and to remove glare by combining asphere in optical system with different concept. To improve luminous intensity uniformity, a reflect mirror system was used after an aspheric optical system design for this study. We made a mirror and measured it after analysing luminance changes depend on aspheric shapes with simulation program to see if aspheric shapes effect luminance distribution. We made progress to find problems and improve them by comparing measured data and analysed data. This result of the study will contribute to industry of LED lighting through developing solution of emotional illumination of LED security lights by knowing the importance of reflectivity with this study and improving luminous intensity uniformity with solving the problem.