• Korean Journal of Materials Research
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• v.29 no.2
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• pp.116-120
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• 2019

We prepared $Y_3Al_5O_{12};Ce^{3+},Pr3^{+}$ transparent ceramic phosphor using a solid state reaction method. By XRD pattern analysis and SEM measurement, our phosphors reveal an Ia-3d(230) space group of cubic structure, and the transparent ceramic phosphor has a polycrystal state with some internal cracks and pores. In the Raman scattering measurement with an increasing temperature, lattice vibrations of the transparent ceramic phosphor decrease due to its more perfect crystal structure and symmetry. Thus, low phonon generation is possible at high temperature. Optical properties of the transparent ceramic phosphor have broader excitation spectra due to a large internal reflection. There is a wide emission band from the green to yellow region, and the red color emission between 610 nm and 640 nm is also observed. The red-yellow phosphor optical characteristics enable a high Color Rendering Index (CRI) in combination with blue emitting LED or LD. Due to its good thermal properties of low phonon generation at high temperature and a wide emission range for high CRI characteristics, the transparent ceramic phosphor is shown to be a good candidate for high power solid state white lighting.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.856-859
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• 2012

In order to cultivate vegetables in plastic greenhouse or housing facilities it was investigated properties of radiation and functions of LED lamp and proposed application possibility. Against presently existing method of obtaining blue and red colored wave lights needed to plants growing, it was used white LED and red LED to investigate growing conditions as well as brightness and color sense with working condition. And also it was presented lighting system of selective wave functions to promote plant growth.

• Korean Journal of Materials Research
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• v.29 no.7
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• pp.437-442
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• 2019

Green $BaSi_2O_2N_2:0.02Eu^{2+}$ phosphor is synthesized through a two-step solid state reaction method. The first firing is for crystallization, and the second firing is for reduction of $Eu^{3+}$ into $Eu^{2+}$ and growth of crystal grains. By thermal analysis, the three-time endothermic reaction is confirmed: pyrolysis reaction of $BaCO_3$ at $900^{\circ}C$ and phase transitions at $1,300^{\circ}C$ and $1,400^{\circ}C$. By structural analysis, it is confirmed that single phase [$BaSi_2O_2N_2$] is obtained with Cmcm space group of orthorhombic structure. After the first firing the morphology is rod-like type and, after the second firing, the morphology becomes round. Our phosphor shows a green emission with a peak position of 495 nm and a peak width of 32 nm due to the $4f^65d^1{\rightarrow}4f^7$ transition of $Eu^{2+}$ ion. An LED package (chip size $5.6{\times}3.0mm$) is fabricated with a mixture of our green $BaSi_2O_2N_2$, and yellow $Y_3Al_5O_{12}$ and red $Sr_2Si_5N_8$ phosphors. The color rendering index (90) is higher than that of the mixture without our green phosphor (82), which indicates that this is an excellent green candidate for white LEDs with a deluxe color rendering index.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.9
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• pp.708-713
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• 2010

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 light emitting diode (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. And at the time of design of ring light, the characteristics of LED and the loss of light at the time of penetrating light diffusion PC were considered so that intensity of illumination for over 150 lx can be obtained. The result of measurement of the intensity of illumination of the ring light that was developed revealed that maximum intensity of illumination of 225.7 lx was obtained, while smoke index was measured to be maximum 78 Ra in the case of Red(50%) Green(100%) and Blue LED(60%). We could confirm that response speed was also very fast as 1.72 ms.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.3
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• pp.183-190
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• 2016

This study carried out an experiment to find out the reaction of hairtail, Trichinus lepturus to the colors of LED light as a basic study on the development of the trolling gear and a method to enable the day-night operation. We used hairtails caught around Seongsan-po, Jeju Island by set nets and hairtail angling. The seven hairtails of the average length 68.9 cm (SD 9.2 cm) and the average weight 135.9 g (SD 47.9 g) were adapted themselves in the experimental water tank, 15 m Self-Governing 1.7 m in height and 1.5 m in depth, and then they were studied. We conducted experiment at the Ocean and Fisheries Research Institute in Jeju Special Self-Governing Province, from November to December 2015, and the sea surface temperature was between 16.5 and $19.5^{\circ}C$. The four colors of LED light, blue, white, green and red, were set up to transmit downward from the marginal area of tank. The 1 meter depth light intensity of LED colors is as follows: $0.09w/m^2/s$ (blue), $0.18w/m^2/s$ (white), $0.04w/m^2/s$ (green) and $0.007w/m^2/s$(red) To know the optimum LED color light, we selected one with better reaction rate after comparison of two colors simultaneously and the selected color was again compared to the other color in a tournament style two times a day (day and night) and ten times totally. The reaction rates were shown as the frequencies of hairtail appearance for 5 minutes in the lighting zone after turning on the LED lights. The reaction rate of the blue was at 97% unlike the red 3% (p < 0.001). The blue was at 75% unlike the green at 25% (p < 0.001). The blue was at 67% unlike the white at 33% (p < 0.001). Therefore, the color of light source showing the highest reaction rate was the blue.

• Korean Journal of Optics and Photonics
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• v.32 no.4
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• pp.163-171
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• 2021

Conventional white light-emitting diodes (LEDs) for lighting applications consist of blue LEDs and yellow phosphors, the spectrum of which lacks deep red. To improve the color-rendering characteristics of white LEDs, a red quantum-dot film was applied to the diffuser plate of LED lighting. The mean free paths of the quantum dots and the concentration of the TiO₂ particles in the diffuser plate were adjusted to optimize the optical structure of the lighting. The color-rendering index (CRI) was greater than 90 for most conditions, which demonstrates that adoption of the red quantum-dot film is an effective way for improving the color-rendering properties of conventional white LEDs. The angular dispersion of color coordinates could be removed by utilizing the optical cavity formed between the diffuser plate and the reflector on the bottom of the lighting, where multiple passages of the light through the quantum-dot film reduced the differences in optical path length depending on the viewing angle.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.110-112
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• 2011

LED조명장치는 기존 광원의 대체품으로 자동차분야, 특수조명, 디스플레이, 항공등 많은 분야에서 활용이 증가하고 있다. 일반적으로 RGB 멀티칩 LED는 천연색 구현이 가능하여 경관조명 또는 감성 조명용으로 적용되고 고출력 백색 LED는 실내외 일반조명 또는 특수조명용으로 적용되고 있으므로 광효율, 연색지수를 증가하기 위한 연구가 계속 진행 중이다. 본 논문에서는 다양한 마이컴 종류 중 하나인 Cypress사의 PSoC을 이용한 LED 조명의 자연광 구현에 대하여 연구하고자 한다. 이를 위해 사이프레스사의 EZ-Color 모듈을 이용한 다양한 색 구현보다 자연광을 구현하기 위한 색온도 가변에 중점을 두고 연구를 수행하였다. 기존에 제시된 날씨와 계절, 시간에 따른 태양광의 색온도 데이터를 이용하여 다양한 색온도를 나타내기 위한 RGB 색혼합 비율에 대해 연구를 수행하였다. 이 연구를 통해 인간을 위한 감성조명의 개발에 참고할 수 있도록 데이터를 제시하고자 한다.

• ETRI Journal
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• v.35 no.5
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• pp.927-930
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• 2013

We propose a visible light communication system in which the color and brightness are controllable. Pulse width modulation and variable pulse position modulation (VPPM) schemes are used to control the color and brightness, respectively. A digital algorithm to decode VPPM signals is suggested and implemented. A seamless transmission is observed in a testbed experiment under various environmental conditions. The proposed scheme can be applied to emotional-lighting-based wireless optical communication.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.108-108
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• 2012

High-performance GaN-based light emitting diodes (LEDs) with high efficiency and excellent reliability have been of technological importance forapplications in full color display, automotive lighting, and solid state lighting. To realize high-performance and excellent-reliability LEDs, various technologies such as surface texturing, transparent conducting oxide, surface Plasmon, highly p-conduction layer, current blocking layer, photon-enhanced layer, and nanostructures have been extensively investigated. Among them, advanced core technologies based on how to suppress surface leakage and current crowding, how to enhance current injection efficiency and output power, and how to resist electrostatic damage will be displayed and discussed using our reported and preliminary results. New approaches like integrated LEDs will be also introduced and discussed.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2008.05a
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• pp.46-49
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• 2008

This research does Complexity form, Interior epidermis cell re-organization, Object discovery that have correct numerical value concept by purpose. Research applied by Grid re-organization in form generation, Parameter variation of cell unit (morphor, tweener), Symbol, pattern of variation, self-organization cell substitution order. Representation through 3d digital modeler of polygon, Nurbs and street-sheet program(x,y,z coordinates & Network way of points) etc. of main work. Investigator specified numbers of U profiles*30, V point-20 that is 600 Paramaters individual in volume, and define circle radius of lighting in object, Projection size variously and tried difference. Transposition cell to point and Heightened brightness of color using pointillism of painting. Led lighting cell object is expressed being decoded by digital code.