• KIEAE Journal
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• v.7 no.1
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• pp.23-31
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• 2007

This study aims to evaluate the illuminance performance of sloped light guide with automated venetian blind systems. For the purpose, a mock-up model was constructed as a prototype of Korean office building with $12.0m{\times}7.3m{\times}3.7m$ ($w{\times}d{\times}h$) and south facing side-window mounted between the clerestory window($2.0m^2$) and the view window($5.6m^2$). The light guide of 1.28m deepth and $29^{\circ}$ tilted angle, is covered with 0.6mm galvanized steel sheet and 97% reflective film. To protect the room from low solar angle, a blind systems, 0.15m deepth and $30^{\circ}$ automated slat angle was installed. To assess illuminance performance, the totally 37 measuring points for illuminance were monitored. For the detailed analysis, photometric sensors were installed at work-plane (8 points), wall (7 points), ceiling (3points), and exterior horizontal illuminance (1 point) respectively. The performance was measured under clear sky and is monitored by Agilent data logger, photometric sensor Li-cor and the Radiant Imaging ProMetric 1400. Comparisons of light factor and uniformity are discussed.

• Restorative Dentistry and Endodontics
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• v.35 no.4
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• pp.235-237
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• 2010

When curing the composite restorations with light curing units, the light guides are often in direct contact with oral tissues, therefore contamination of light guides is inevitable. Curing light guides fall into the "semicritical" instrument category according to the Centers for Disease Control and Prevention (CDC) and must be heat or vapor-sterilized or at a minimum, these semicritical instruments must be sterilized in a liquid chemical agent. Currently, most common methods of maintaining sterility of the light guides are wiping the guide with a disinfectant, such as glutaraldehyde, after each patient use; using autoclavable guides; using presterilized, single-use plastic guides; and using translucent disposable barriers to cover the guide.

• Journal of the Korean Society of Radiology
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• v.17 no.5
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• pp.671-677
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• 2023

When a scintillator block is constructed using fine scintillator pixels, the scintillator block located at the edge of the scintillator block results in overlapping images. To solve this problem, a light guide was inserted between the scintillator block and the photosensor, and images of all scintillation pixels were separated and acquired. However, loss of light may occur through the light guide, which eventually affects the quality of the image due to a decrease in energy resolution. Therefore, in this study, a detector was designed that can separate scintilltion pixels better by using a reflector on the side of the light guide and can secre excellent energy resolution by minimizing light loss. For comparative evaluation with previous studies, flood images were obtained through DETECT2000 capable of light simulation, and the degree of separation and light collection rate were evaluated. When a reflector was used on the side of the light guide, all materials showed excellent separation regardless of the material of the light guide, which showed better separation results than previous studies. In addition, the light collection rate was more that five times better when the reflector was applied than when it wa not. If this detector is applied to a small animal positron emission tomography, it will be possilbe to secre excellent image quality through excellent spatial resolution and energy resolution.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1609-1612
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• 2005

The effects of injection molding conditions on the uniformity and brightness of light guide plate(LGP) with micro-patterns were investigated in the present study. An injection molding system for stampers with mirco-pattern was designed and manufactured to perform experiment. Variations of injection molding speed, mold and melt temperature for LGP were considered in this work. Also, injection molding characteristics of LGP were investigated by numerical analysis using plastic injection molding commercial code. It was shown that injection molding conditions such as injection speed, melt temperature and mold temperature can have an effect on the uniformity and brightness of light guide plate.

• Journal of Information Display
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• v.5 no.1
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• pp.7-15
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• 2004

A highly simplified backlight unit mainly composed of diffractive grating in sub-micron order imprinted light-guide plate (LGP) is proposed for edge-lit backlight unit. Optical characteristics of the imprinted LGP are examined by RCWA and the performance is verified through Monte Carlo simulation. Results show that the diffraction efficiency, luminous flux and its uniformity over the area are significantly affected by the angle of incident ray. Consequently couples of design considerations are additionally proposed to enhance luminous flux. In terms of peak luminance and out-coupling luminous flux, the experimental results are agreed well with the performance simulation. Finally, compared with optical characteristics of conventional backlight unit, we could conclude that the proposed simplified backlight unit made of diffractive grating imprinted light-guide plate is a good substitute for the conventional backlight unit.

• Journal of the Optical Society of Korea
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• v.19 no.2
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• pp.159-164
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• 2015

In the injection-molded light guide plate the replication quality, i.e. the reproduction accuracy, of micro-patterns should be high and uniform over the entire surface area. However technical difficulty in meeting the necessary replication quality arises as the plate size becomes large for TV applications. We propose a simulation technique to optimize the distribution of micro-patterns on a 55-inch injection molded light guide plate considering non-ideal replication quality of micro-patterns. The luminance uniformity could be improved by more than 16% by optimizing the pattern distribution in spite of the same replication quality.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.66 no.4
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• pp.242-246
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• 2017

In this study, it was investigated about optical simulation in high brightness and high uniformity general lighting using glass light guide plate. And we adopt edge-light emission type light plate. Edge-light type lighting has been used LCD application, especially note PC or smart phone backlight unit. Because it had the good properties such as slim shape and light weight. We thought this type was suitable for general lighting application such as wall attached type or ceiling mount type. But many of edge-light type lighting had problems. It called slanted output light rays. That was main key parameter how could control the direction of output light rays. We investigated the solution of this problems, using ray tracing method, we recognized the major fact of the solution relied on the geometric structure of diffusing dot shape. We set the conditions of aspect ratio in diffusing dot shape such as 0.5 to 1. And, at first, we designed diffusing dots shape based on the results of optical simulation and made specimen. as above condition, and acquired good result in confirming dots shape such as the value of the output rays's peak angle was around 75 degrees. And good light distribution characteristics were measured by slated spectro-radiometer. It was shown that the effective ways of designing light distribution characteristics using optical simulation such as ray tracing linear method for making general lighting using glass light guide plate.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.1047-1048
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• 2012

• Journal of the Korean Society for Precision Engineering
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• v.28 no.2
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• pp.133-139
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• 2011

We have performed optical design of light guide plates (LGPs) for a photobioreactor by using an illumination design tool. An LGP having light emitting diodes (LEDs) as a light source on the four sides was designed by optimizing the distribution of LGP patterns and design of another LGP, on top of which sunlight was focused by a Fresnel lens, was executed. Finally, a hybrid-solar-and-LED-lighting scheme was described. Detailed design process and optical performances of the designed LGPs are presented.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.4
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• pp.30-35
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• 2020

The light guide plate (LGP) provides a surface light source on the back of the liquid crystal display (LCD), which is not self-emitting; thus, it is an essential component of display units requiring sufficient brightness. To maximize the light-emitting effect of an LGP, enough incident light, from the light source, should enter into its side. However, the current trend in LCD panels is represented by larger and thinner screens and this smaller thickness prevents the accordingly thin LGPs from providing sufficient brightness. This paper proposes a process for manufacturing wedge-type LGPs, which might increase the amount of incident light and, consequently the surface light emission, for applications in large LCDs. The proposed method was validated by building a dedicated manufacturing machine and performing illuminance experiments on the fabricated LGP.