• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.1
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• pp.296-305
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• 2012

In this paper, we develop about glare phenomenon at security light caused by light source's straight characteristic, maintaining uniformity ratio of illuminance as high, have long light distribution not by symmetry of rotation but a single axis. we develop second lens for security light that lack of light distribution phenomenon at each of security light can be solved. Our developed light system design satisfies lighting standard of security light's and shape of lens is single lens. so our lens optimizes designing or analysis by using lighting design and interpretation program. Making a Mock-up to do real measure, we have intensity of illumination and maintaining uniformity ratio of illuminance measurement data.

• Journal of the Korean Solar Energy Society
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• v.32 no.1
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• pp.48-55
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• 2012

In recent years, it clearly shows the tendency toward the utilization of daylight in many exhibitory buildings such as museum since the expectation of visitors for whom high illuminance levels are preferable to perceive the details of the works of art. Shading devices and special glazings are often used as the tool to control the amount of light and heat which should be avoided for the presentation of high-light sensitive art works such as paintings. Another way of controling the light is to provide the space for inducing and attenuating light in the exhibitory building. This study aims to investigate the illuminance on the exhibitory space when the space for inducing and attenuating light is applied. Interaction between the daylight and the space was simulated by Lumen Micro program with variation of the size of the exhibitory space, the length of inner wall, surface reflectivity, area of windows to obtain the illumination of the wall surface. This study shows that those variables affect the illumination on the wall surfaces. By comparing the results with suggestive illumination of KS and ICOM, available wall for display on natural lighting are suggested for the seasons and time.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.05a
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• pp.129-134
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• 2009

The actual conditions of school illumination was investigated. The illumination state was classified by the number of installed luminaires per 1 classroom. The illuminance state was measured and analyzed. The work surface illuminance was up to the standard, but the illuminance on blackboard was below standard when there was no local illumination. As a result of conducting a simulation based on the mesurement of the reflection factors of the classroom finishing materials and lamp replacement and lamp cleaning, nine luminaires for general lighting and local lighting for the blackboard were required, and the kind of design considered illumination maintenance was called for.

• Journal of the Semiconductor & Display Technology
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• v.18 no.4
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• pp.51-56
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• 2019

LuAG:Ce(Lu₃Al₅O₁₂:Ce³⁺) nano phosphor were synthesized by applying the coprecipitation method. It is used to increase the color rendering of phosphor ceramic plate for high power LEDs and laser lighting. Internal quantum efficiency and absorption of LuAG:Ce nano phosphor are 51.5 % and 64.4 %, respectively, which is higher than the previously studied nano phosphors. The maximum absorption wavelength of this phosphor is 450 nm blue light, and the emission wavelength is 510 nm. The emission wavelength shifted to longer wavelength when the concentration of Ce increased in the heat treatment of the reducing atmosphere. Thermal quenching of LuAG nano phosphor was 70 % at 200 ℃, it was explained by their significant quenching of all raman scattering modes, implying the restriction of electron-phonon couplings caused by their defects.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.14-19
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• 2019

In this study, the Relux illumination program was used to simulate the optimal lighting design for a glass greenhouse with Si and DSSC solar-cells and LEDs. The results of the daylight simulation show that the optimum conditions were a structure angle of 90o and higher transmittance. The results of the illumination simulation produced a power consumption effect of 5.6 kwh in the summer (42[%] energy savings compared to full LED control) and 7.8 kwh in the winter (58[%] energy savings compared to full LED control). The results suggest that ginseng should be grown in an energy-saving glass greenhouse.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.3
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• pp.194-200
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• 2020

Perylene bisimide derivatives are developed for red organic phosphor because of their advantages, such as excellent luminous efficiency and high thermal stability. Despite these advantages, they have poor solubility characteristics in organic solvents and short emission wavelength as red organic phosphor for hybrid light-emitting diodes (LEDs). In this study, we prepared terrylene bisimide using a coupling reaction and swallow-tail imide group, which has excellent solubility. The structures and properties of swallow-tail terrylene bisimide (9C) were analyzed using ¹H-nuclear magnetic resonance (¹H-NMR), Fourier-transform infrared (FT-IR), UV/Vis spectroscopy, and thermal gravimetric analysis (TGA). The maximum absorption wavelength of (9C) in the UV/Vis spectrum was 647 nm, and the maximum emission wavelength was 676 nm. In the TGA, (9C) demonstrated good thermal stability with less than 5 wt% weight loss up to 415℃. In the solubility test, (9C) has a good solubility of more than 5 wt% in chloroform and dichloromethane. When the compounds (9C) were mixed with PMMA (polymethly methacrylate), the films showed peaks at 680 nm in the PL spectra. The results verify the suitability of (9C) as a red organic phosphor for hybrid LEDs.

• Journal of the Semiconductor & Display Technology
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• v.18 no.1
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• pp.10-14
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• 2019

In this study, we synthesized two $Y_3Al_5O_{12}:Ce^{3+}$ phosphors ($7{\mu}m$-sized and $2{\mu}m$-sized YAG) with different sizes by controlling particles sizes of starting materials of the phosphors for white LED. In the smaller one ($2{\mu}m$-sized YAG), its photoluminescence intensity in the reflective mode was 63 % that of the bigger one ($7{\mu}m$-sized YAG); the quantum efficiencies were 93 % and 70 % for the smaller and the bigger ones. Two kinds of white LED packages with the same color coordinates were fabricated with a blue package (chip size $53{\times}30$) and two phosphors. The luminous flux of the white LED package with the smaller YAG phosphor was 92 % of that with the bigger one, indicating that the quantum efficiency of phosphor dispersed inside LED package was higher than that of the pure powder. It was consistently confirmed by the optical simulation (LightTools 6.3). It is notable according to the optical simulation that the white LED with the smaller phosphor showed 24 % higher luminous efficiency. If the smaller one had the same quantum efficiency as the bigger one (~93 %). Therefore, it can be suggested that the higher luminous efficiency of white LED can be possible by reducing the particle size of the phosphor along with maintaining its similar quantum efficiency.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.3
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• pp.260-265
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• 2003

The energy of PV system is different as the elevation and aximuth of the sun. This paper deals with the economical position tracking system development for the stand alone PV system. We have made more economical solar position tracking system which is used a tracking program than other similar systems. It is applied to the solar lighting lamp. We have made a comparative study of the energy amount between the fixed type and the tracking type during some period. The improved efficiency of the system is about 86 %.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.10
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• pp.1183-1189
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• 1999

This paper presents the method of parameter estimation of diffusion model for monitoring Demand-Side Management program. Bass diffusion model was applied in this paper, which has different values according to the following parameters; coefficients of innovation, imitation and potential adopters. Though it is very important to estimate three parameters precisely, there has been no empirical way in practice. Thus, this paper presents the method of parameter estimation in case of few data with constraints to reduce the possibility of bad estimation. The constraints can be empirical results or expert's decision. Case studies show the diffusion curves and forecasted values of the peak for the high-efficient lighting. The feedback and nonlinear least-square parameter estimation methods used in this paper enable us to evaluate the status and to predict the effect of DSM program.

• KIEAE Journal
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• v.4 no.4
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• pp.45-52
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• 2004

Simulation of daylighting by computer program is a method to avoid unnecessary efforts in manufacture of its testing models, to reduce its measuring tolerances and be able to provide variations of various weather conditions as well. Many simulation programs on daylighting have been released freely or commercialized for selling, however, a demonstration of their availability and validity as a tool for evaluating daylighting performance is required since each one has its own characteristics. The objectives of this study lie in suggesting an application method of evaluation tools and demonstration of limits and characteristics so as to more easily determine the daylightingperformance in the very initial stages of planning for an arbitrary office space in which windows with daylight access are built. We produced scale model of the general light inducing type side lighting with lightshelfand ceiling, and the luminance (at 78 measuring points) and illuminance (at 84 measuring points) were measured in a clear sky. And a comparison of the measured values and the calculated values from a computer simulation using the Lightscape program was performed.