• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.4
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• pp.6-13
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• 2012

In this paper, we took an indirect reflectance type that irradiates light from an LED module, which reflects light from a reflector onto the road. This LED pedestrian lighting design produces minimal glare from a relatively simple structure. Using LightTools 7.2, we conducted a study on the varying shape and curvature of the reflector. In order to further investigate this data, we researched the ratio of the DLOR and ULOR, the average illuminance, and the uniformity of the illumination. Based on this research, we selected optimum conditions to realize the actual LED pedestrian lighting using RELUX software. We found the average illuminance value to be 22[1x] and the illuminance uniformity ratio to be 0.23, which met the criteria of the proposed standards set in KS C 7658. In addition, it also satisfied the criteria of the standards set in KS A 3701 by having TI (Threshold Increment) at 7[%].

• Korean Journal of Optics and Photonics
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• v.26 no.4
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• pp.226-232
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• 2015

A double-layer LED array together with an illumination optical system is proposed as a possible light source for LC projection display systems for large screens, up to $8m{\times}6m$ (400 inches diagonal). The heat dissipation problem of the LED array is solved by arranging the LEDs in double layers, and thermal analysis shows its effectiveness. The light from the LEDs in the back layer can be transmitted through the front layer without significant loss by arranging the LEDs in non-overlapping positions in the two layers and inserting suitable microlenses between the two layers and holes in the first layer. Together with the double-layer LEDs, an illumination optical system is designed to illuminate liquid crystal panels with good uniformity and appropriate matching with the projection optics.

• Current Optics and Photonics
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• v.1 no.1
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• pp.23-28
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• 2017

The laser has been regarded as the potential illumination source for the next generation of projectors. However, currently the major issues in applying the laser as an illumination source for projectors are beam shaping and laser speckle. We present a compact solution for both issues by using a vibrating diffractive optical element (DOE). The DOE is designed and fabricated, and it successfully transforms the circular Gaussian laser beam to a low speckle contrast uniform rectangular pattern. Under a vibration frequency of 150 Hz and amplitude of $200{\mu}m$, the speckle contrast value is reduced from 67.67% to 13.78%, and the ANSI uniformity is improved from 24.36% to 85.54%. The experimental results demonstrate the feasibility and potential of the proposed scheme, and the proposed method is a feasible approach to the miniaturization of laser projection display illumination systems.

• Korean Journal of Optics and Photonics
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• v.18 no.1
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• pp.74-78
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• 2007

We report theoretical and experimental results for application of transmittance-controlled photomask technology to ArF lithography. The transmittance-controlled photomask technology is thought to be a promising technique fo critical dimension (CD) uniformity correction on a wafer by use of phase patterns on the backside of a photomask. We could theoretically reproduce experimental results for illumination intensity drop with respect to the variation of backside phase patterns by considering light propagation from the backside to the front side of a photomask at the ArF lithography wavelength. We applied the transmittance-controlled photomask technology to ArF lithography for a critical layer of DRAM (Dynamic Random Access Memory) having a 110-nm design rule and found that the in-field CD uniformity value was improved from 13.8 nm to 9.7 nm in $3{\sigma}$.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.9
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• pp.1-7
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• 2008

This study is intended to compare physical properties of fluorescent luminaires with ones of LED luminaires so as to analyze fundamental characteristics of LED luminaires. For this, a comparative analysis of uniformity ratio of illuminance and luminance distribution of these two luminaires was made, and materials for applying LED luminaires to interior construction space were prepared. This study was carried out in four stages. First, a theoretical review on LED illumination light source was made compared with the existing luminaires. Second, a mock-up to control experimental variables to meet the objective of this study was manufactured. Third uniformity ratio of illuminance and luminance distribution of each luminaire were measured by using the mock-up. Fourth, a comparative analysis of uniformity ratio of illuminance and characteristics of luminance distribution of the existing fluorescent luminaires and LED ones was made. As a result of the study, the uniformity ratio of illuminance of LED luminaires, 0.559, was higher than one of the existing fluorescent luminaires, 0.522. Namely, it was shown that illuminance distribution of LED luminaires was uniform and global diffuse was good. As a result of measuring luminance distribution, it was found that luminance distribution of LED luminaires was more uniform than one of the existing fluorescent luminaires. The maximum luminance of fluorescent luminaires and LED luminaires over the wall was $180.6[cd/m^2]$ and $155.26[cd/m^2]$ respectively. Namely, the maximum luminance of fluorescent luminaires was higher than one of LED luminaires. The average luminance of fluorescent luminaires and LED luminaires was $44.32[cd/m^2]$ and $58.65[cd/m^2]$. Like this, the average luminance of LED luminaires was higher than one of fluorescent luminaires. Considering these results, it's thought that LED luminaires can give a person in the room a more comfortable working environment than fluorescent luminaires.

• Journal of the Korean Society of Industry Convergence
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• v.4 no.1
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• pp.71-75
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• 2001

This study investigates the relationship between size of cosmetic shops, size of showcases, sorts and arrangement of light source, floor plan, and illuminance measured of interior space. From this result, the average space size of cosmetic shops were $623.2{\times}512.9{\times}258.1cm$(width, length, height), the average space size of showcases were $273.3{\times}53.8{\times}89.5cm$ (width, depth, height). The light source was most frequently used fluorescent lamp, and illuminance was the most highest nearby main showcase, and average illuminance were 722[Ix], uniformity were 0.3.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.3
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• pp.480-487
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• 2013

In this study, we researched the LED source MR16,which maintains the strong points of an ordinary MR16 while compensating for its weak points. The optical system composition of the LED MR16 includes four aspherical lens per sheet and a patterned reflector. The aspherical optical system and reflector were designed using optical software, and the performance was estimated using a lighting simulation program. Finally, a prototype was manufactured after analyzing the simulation data, and the reliability of the simulation results was estimated using a comparative analysis of the designed data and measured data.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.3-7
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• 2005

A lighting method of our county is ordinary center concentration form. Therefore, it is usally used the Five Point Method, Multiplicity Method of KS, and Four Point Method of IES to measure a space illuminance. We can use the Five Point Method of KS when we measure a uniformity ratio or activities that happen in space is more sensitive than whole illumination. In addition, we can use the Multiplicity Method of KS and Four Point Method of IES when we measure whole illuminance like mean illuminance. Such method of measurements should be used exactly according to the kinds of space and activities.

• Korean Institute of Interior Design Journal
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• v.24 no.4
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• pp.91-98
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• 2015

Double skin façade is known that several features affected the building energy and daylighting performance. That is why the envelope is able to consist of all architectural materials such as glass, aluminum, wood and insulation for vision of residents and workers in buildings. Its specifications is very diverse according to the building designers and building owners. In recent times, visual environment became a major focus and resulted in the development of cutting edge engineering of diverse glazing systems and shading devices by growing interests of friendly environment. Thus this research has evaluated the fluctuations of interior lighting and atmospheric conditions based on double skin facade systems. Especially in terms of daylighting environment as dependent on solar variations, this research provides quantitative analysis of interior lighting conditions and how it affects the living conditions as well as improve the design of interior spaces.

• Korean Journal of Optics and Photonics
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• v.9 no.3
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• pp.205-211
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• 1998

The MTF(modulation transfer function) measuring system with a linear CCD(charge coupled-device) was constructed to cvaluate a color CRT(catode ray tube). The measured MTF values were corrected by considering the spectral response and the pixel sizes of CCD. The effects of a spot size, video bandwidth, pitch of shadow mask holes, display luminance, and ambient illumination on image quality were studied. The uniformity of resolution and the contrast Ioss by ambient light of the color CRT monitor were measured, and the results were analyzed by MTFA(modulation threshold area).