• 한국자동차공학회논문집
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• 제5권6호
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• pp.167-174
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• 1997

The penetration depth and the size distribution of the droplets of fuel sprays are important in the operation of spark-ignition MPI engines. A fluorescence/scattering image technique for droplet sizing was applied to measure th edroplet size distribution in non-evaporating gasoline sprays. The fluorescence and scattering lights were imaged simultaneously by the two-dimensional visualization system composed of a laser sheet, a doubling prism, optical filters, and a CCD camera. Quantitative droplet size distributions were extracted from evaluating the ratio of the two light densities. The mean droplet size measured by the fluorescence/scattering technique was compared with the result obtained by the enlarged photographs of droplets. The fluorescence/scattering image technique also gives the useful information of the characteristics of droplet impingement in a inclined wall.

• 한국광학회지
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• 제21권2호
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• pp.53-60
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• 2010

본 논문에서는 휴대전화용 백라이트 유닛의 광학시트를 줄이면서도 휘도와 휘도균일도 및 시야각을 유지하기 위한 복합 도광판을 설계하고 가공하였다. 복합 도광판의 패턴은 가공성을 고려하여 윗면에는 마이크로 급의 프리즘 패턴을 형성하고 아랫면은 나노 및 마이크로 급의 크기가 다른 두 개의 음각 프리즘 패턴을 형성하였다. 이러한 패턴 형상은 금형 코어를 이용한 사출성형을 통해 복합 도광판의 가공성을 확인하였다. 특히 최적화된 복합 도광판은 프리즘 시트 한 장만을 채용하여 통상적인 백라이트 유닛과 유사한 휘도 4560 cd/$m^2$, 휘도균일도 83%, 수직 시야각 $60^{\circ}$, 수평 시야각 $56^{\circ}$라는 성과를 얻을 수 있었다. 결과적으로 도광판의 윗면과 아랫면에 복합 패턴들을 형성함으로써 기존의 백라이트 유닛에서 확산시트 및 프리즘시트 1장을 제거하여 BLU에 적용될 수 있음을 확인하였다.

• 한국광학회지
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• 제23권3호
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• pp.119-123
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• 2012

LCD backlight unit (BLU)에서 도광판 상부에 micro reverse-pyramid array (MRPA) 또는 micro reverse-cone array (MRCA)을 설치함으로써 기존의 확산 시트와 프리즘 시트를 없애고 구조를 단순화하였으며, 광학적 시뮬레이션을 통하여 새로운 도광판의 최적 조건을 얻었다. MRPA와 MRCA의 측면각과 높이, 윗변의 반지름이나 윗변의 길이에 따라 휘도와 시야각의 변화를 구하였다. MRPA와 MRCA 구조물의 최적의 형상은 측면각이 각각 59도와 57도이었으며, 시야각은 68도와 64도이었다. 구조물의 높이는 큰 영향을 주지 않았다.

• 정보저장시스템학회논문집
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• 제9권1호
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• pp.10-16
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• 2013

Through the rapid development of LED TV, a large-area edge-lit backlight unit is widely researched in the display industry for enhancing the optical efficiency, luminous uniformity and slim design. In addition, an edge-lit backlight unit includes many optical sheets such as reflection sheet, prism sheet and diffuser sheet. However the function can be replaced by the carefully patterned light guide plate (LGP). Micro patterns which located on the top and bottom surface of light guide plate was designed by ray-tracing optical simulation. The designed patterns improved the light characteristics of LGP, including optical extraction efficiency and intensity distribution uniformity. These results suggest that it is very effective method to design edge-lit LGP with micro-patterns on both sides for large-area display and to reduce the fabrication cost.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1597-1600
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• 2005

Recently, the trends of TFT-LCD are large scale and thin thickness, so, the demands of Light Guide Panel(LGP) which is able to substitute for prism sheets are appeared. Functions of LGP obtaining polarization of light of the prism sheet as well as the incidence and reflection of light are demanded. This prismless type LGP to complete functions of the existing LGP and polarization at once must be supported by micro machining technology of LGP surface. In this research, we have used the STAMPER method for the mass product and In-Line process, and the optimized conditions are established by analyzing the cutting force and conditions according to the material and processing properties when the prismless type LGP mold is fabricated. Parameters of the cutting condition were the workpiece and cutting depth.

• 한국생산제조학회지
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• 제22권2호
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• pp.263-267
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• 2013

The continuing demand for increasingly slimmer and brighter liquid crystal display (LCD) panels has led to an increased focus on the role of light guide panels (LGPs) or optical films that are used to obtain diffuse, uniform light from the backlight unit (BLU). The most basic process in the production of such BLU components is the micromachining of V-shaped grooves. Thus, given the current trend, micromachining of V-shaped grooves is expected to play increasingly important roles in today's manufacturing technology. LCD BLUs comprise various optical elements such as a LGP, diffuser sheet, prism sheet, and protector sheet with V-shaped grooves. High-aspect-ratio patterns are required to reduce the number of sheets and enhance light efficiency, but there is a limit to the aspect ratio achievable for a given material and cutting tool. Therefore, this study comprised a series of experimental evaluations conducted to determine the machining limit in microcutting V-shaped grooves on electroless nickel plated die materials when using single-crystal diamond tools with point angles of $20^{\circ}-80^{\circ}$. Cutting performance was evaluated at various cutting speeds and depths of cut using different machining methods and machine tools. The experimental results are that V-shaped patterns with angles of $80^{\circ}$ or up can be realized regardless of the machining conditions and equipment. Moreover, the feed rate has little effect on machinability, and it is thought that the fly-cut method is more efficient for shallow patterns.

• 소성∙가공
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• 제11권4호
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• pp.341-348
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• 2002

For the light guide plate of the TFT-LCD, there have been increasing demands for higher brightness, thin and light-weight design, and lower power consumption. To meet these demands, a micro-prism-type frontlight that integrates a prismatic sheet and a light-guiding plate has been developed. In this paper, the influences of processing conditions on the brightness were studied lot the injection molding of the light guide plate. Based on the experiment with an actual mold, the design of experiments and the neural network theory were used lot choosing the optimal processing parameters to increase the brightness and the uniformity. The verification experiment also showed that the brightness and the uniformity were increased dramatically with the chosen processing conditions.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집B
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• pp.353-358
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• 2000

To achieve the requirement for high fuel economy and low emissions, the research for GDI engines is recently very brisk in the whole world. This study was performed to measure distribution of average particle size in non-evaporating spray. The 2-D fluorescence/scattering images of fuel spray were captured simultaneously by visualization system composed of a laser sheet, a doubling prism, optical filters, and an ICCD camera. Using the ratio of the two light intensities, particle size distribution was obtained. The SMD measured by fluorescence/scattering technique was compared with it obtained by PDA. The experimental results show that the spray structure of GDI injector and temporal SMD distribution.

• 한국광학회지
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• 제20권2호
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• pp.118-122
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• 2009

PET 필름 위에 LCD 백라이트의 프리즘 집광시트의 역할을 대체 할 수 있는 microlens array(MLA) 시트를 설계하고 제작하였다. Photoresist thermal reflow 공정으로 두께 $100{\mu}m$ PET 필름 위에 MLA를 제작하였고, 노광 시간과 reflow의 온도, 시간 등의 변수에 따른 MLA의 형상 변화를 측정하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 C
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• pp.1041-1043
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• 1999

In this work, a possible new PD detection technique, based on the electro-optic effect, has been proposed. A proto-type probe sensor for detection partial discharge is made by $LiNbO_3$ Pockels cell, diachroic sheet polarizer and right-angle prism. The Mach-Zehnder interferometer system is proposed by using this sensor and this system is applied to detecting high electric field. we show the characteristic of the proto-type probe sensor and the design of a proposed probe type sensor.