• 한국정밀공학회지
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• 제25권12호
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• pp.132-138
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• 2008

Recently, mastering processes for high density optical disc such as Blu-ray disc rely on electron beams, which are operable in only vacuum. In the mastering process, one of the most important tasks is to design precision stages for providing precise positioning of the works with respect to the source in a high vacuum environment. In this paper, we have developed a precision rotation table usable in the electron beam mastering. The rotation table adopted air bearings for a high positioning repeatability and velocity stability. The air leakage from the air bearings has been minimized by employing the differential exhaust scheme using three steps of air drain. The design parameters such as diameters of exhaust lines, seal lengths, and pumping speeds were decided according to the optimization method using genetic algorithm. The performance on the vacuum level of the rotation table was evaluated experimentally and theoretically. The results indicate that a vacuum level of $10^{-4}$ Pa is achieved with operation of air bearings in a vacuum chamber, which is sufficient for the electron beam mastering.

• Korea-Australia Rheology Journal
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• 제19권3호
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• pp.171-176
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• 2007

LCD-BLU (Liquid Crystal Display-Back Light Unit) of medium size is usually manufactured by forming numerous dots with $50{\sim}300\;{\mu}m$ in diameter by etching process and V-grove shape with $50\;{\mu}m$ in height by mechanical cutting process. However, the surface of the etched dots is very rough due to the characteristics of the etching process and V-cutting needs rather high cost. Instead of existing optical pattern made by etching and mechanical cutting, 3-dimensional continuous micro-lens of $200\;{\mu}m$ in diameter was applied in the present study. The continuous micro-lens pattern fabricated by modified LIGA with thermal reflow process was tested to this new optical design of LGP. The manufacturing process using LIGA-reflow is made up of three stages as follows: (i) the stage of lithography, (ii) the stage of thermal reflow process and (iii) the stage of electroplating. The continuous micro-lens patterned LGP was fabricated with injection molding and its test results showed the possibility of commercial use in the future.

• 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.

• 대한전자공학회논문지TC
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• 제47권12호
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• pp.24-30
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• 2010

Super-RENS (Super-Resolution Near-field Structure) 디스크 시스템은 BD (Blu-ray Disc) 이후의 차세대 광 기록 저장 시스템의 유망한 후보이다. 따라서 super-RENS 시스템을 위한 등화기 개발과 성능 분석을 위해 정확하고 신뢰성 있는 채널 모델링은 매우 중요하다. 본 논문에서는 super-RENS 시스템의 모델링을 위해 SCPWL (Simplicial Canonical Piecewise-Linear) 모델을 적용하고자 한다. Super-RENS 디스크로부터 획득한 RF 신호 샘플들을 사용하여 모의실험을 수행한 결과, super-RENS 시스템의 비선형 모델링을 위해 SCPWL 모델이 효과적으로 활용될 수 있다는 것을 확인하였다.

• 조명전기설비학회논문지
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• 제24권5호
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• pp.1-7
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• 2010

광원으로써 다양한 장점을 가지고 있는 LED 소자는 응용 분야의 확대가 빠르게 진행되고 있다. 특히 조명 분야의 LED 응용은 더욱 활발하다. 본 논문에서는 비교적 낮은 광량이 요구되는 옥내 외 문자표시용 광원, 양면 발광형 광원, 저휘도 LED BLU 분야에 적합하도록 투명 Plate와 LED 칩을 조합하여 광원을 구현하였다. 투명광원 구현을 위해 폴리카보네이트 계열의 plate 사용하였으며 LED 칩의 구동을 위한 구리회로를 plate 표면에 형성하였다. 또한 기존 패키지를 사용하던 LED 광원 대신 투명 plate 표면에 LED 칩을 직접 장착하는 기술을 적용하였다. 최종 제품은 다수개의 광원 모듈을 결합하여 BLU또는 면광원에 적합한 샘플을 제작하였다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2005년도 추계종합학술대회
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• pp.906-910
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• 2005

본 논문에서는 이미 표준화 된 휘도에서 고 휘도를 향상을 시키기 위해서 휘도 향상에 직접영향을 미치는 실험모델을 제안 하였다. 국산램프(K社)와 일본램프의 제품에서 ${\phi}$2.6램프보다 ${\phi}$l.6램프을 사용함으로 세경화에 따라 200[cd/m$^2$]정도 휘도가 향상됨을 알 수 있었다. 기존에 BLU상에서는 LCD Panel을 장착하면 그 휘도는 초기램프 보다 약 1/100 - 1/200정도로 낮아진다. 시트 Variation에 따른 비교분석을 한 결과 시트 구성인 'LCP + DIFFUSER + BEF II(H) + BEFII(V)' 구성이 가장 고휘도 분포가 나타나는 것을 알 수 있으며, 고 휘도 구현을 하기위한 효율적인 구성 기준을 제안하였다.

• 한국표면공학회지
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• 제49권2호
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• pp.178-185
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• 2016

In this study, we have fabricated light guide plates (LGPs) in thin film form for edge type back light unit (BLU) by using UV imprint lithography. In the LGPs, the pattern of functional resins on PC and PMMA substrates were successfully transferred from original master mold through PVC stamp. Optimized pattern arrays with slowly-sloped density were designed to obtain high brightness and uniformity. We could obtain a relatively improved brightness of $950cd/m^2$ and a uniformity of 87.3% by using the NP-S20 functional resins at an input power of 1.3 W because NP-S20 resin could show high formability after UV hardening process. The LGP prepared on polymethylmethacrylate (PMMA) substrate exhibited higher brightness than that on polycarbonate (PC) substrate because PMMA has lower refractive index resulting in more refraction toward the vertical direction.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.414-415
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• 2006

At present, Characteristic of high color reproduction for LCD products needed in Display market. Therefore, The improving methods of high color reproduction are alteration of color Filter or Red, Green, Blue phosphor alteration of CCFL. But High color reproduction phosphor is short life time as compared with conventional phosphor. In this experiment, by using split the Red, Green, Blue CCFL with high color reproduction phosphor instead of conventional high color reproduction CCFL. We knew that the high color reproduction RGB split CCFL BLU has same spectrum data and chromaticity, but has long life time as manufacturing RGB split CCFL and reduce chromaticity shift following long time discharge as compared with conventional high color reproduction CCFL.

• 한국재료학회지
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• 제19권1호
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• pp.7-12
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• 2009

TFT-LCD is the most popular type of flat display panel in the information technology field. The back light unit is a main part of the structure of a TFT-LCD panel. Occasionally, studies have shown that failures of the CCFL of the BLU occur due to the poor weld characteristics of these materials. The aim of this study was to prepare some technical data and to characterize a microjoined electrode for the CCFL. Microstructure examinations, microhardness measurements, resistance measurements and microtensile tests of the microjoined electrode were carried out. The result indicates that a large amount of grain coarsening exists in the heat-affected zone (HAZ) of the weld between the cup and the pin. This grain coarsening of the HAZ between the cup and pin is caused by the welding cycle, which may have an influence on the lowest microhardness values. Fracturing of the microjoined electrode also occurred at the HAZ close to the cup between the weld holding the cup and the pin. Additionally, no specific changes of the electrical resistance among the cup, pin, and lead wire themselves or in the microjoined electrode were observed.

• 한국정밀공학회지
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• 제16권9호
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• pp.172-178
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• 1999

3D linear and circular interpolations are a basic part for the machining of complex shapes. Until now, because of the absence of appropriate algorithms for the generation of 3D lines and circles, a full accomplishment for available machine tool resolution is difficult. this paper presents new algorithms for 3D linear and circular interpolation in the reference pulse technique. In 3D space, the line or circle is not expressed as an implicit function, it is only defined as the intersection of two surfaces. A 3D line is defined as the intersection of two planes, and a 3D circle is defined as the intersection of a plane and the surface of a sphere. Based on these concepts, interpolation algorithms are designed to follow intersection curves in 3D space, and a real-time 3D linear and circular interpolator was developed in software using a PC. The algorithm implemented in a PC showed promising results in interpolation error and speed performance. It is expected that it can be applied to the next generation computerized numerical control systems for the machining of 3D lines, circles and some other complex shapes.