• International Journal of Control, Automation, and Systems
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• 제3권1호
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• pp.130-136
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• 2005

A new optical digitizing system for determining the position of a cursor in three dimensions(3D) and an experimental device for its measurement are presented. A semi-passive system using light intensity modulation, a technology that is well known in radar ranging, is employed in order to overcome precision limitations imposed by background light. This system consists of a charge-coupled device camera placed before a rotating mirror and a light-emitting diode whose intensity is modulated. Using a Fresnel pattern for light modulation, it is verified that a substantial improvement of the signal to noise ratio is realized for the background noise and that a resolution of less than a single pixel can be achieved. This opens the doorway to the realization of high precision 3D digitized measurement. We further propose that a 3D position measurement with a monocular optical system can be realized by a numerical experiment if a linear-period modulated waveform is adopted as the light-modulating one.

• 대한전자공학회논문지SD
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• 제48권3호
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• pp.12-17
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• 2011

본 논문에서는 기존의 대면적 수평형 GaN (Gallium Nitride) LED (Light-emitting diode) 전극패턴이 갖는 전류의 집중현상 및 소자 내 발열문제를 최소화하고 전기적 광학적 특성의 향상을 위하여 팔각 핑거 타입의 전극패턴을 제안하였고, 범용적으로 사용되는 기본 전극패턴 및 그를 대칭적으로 개량한 전극패턴과의 특성을 비교 분석하였다. 상용 3차원 시뮬레이터 SpecLED/RATRO를 통한 시뮬레이션 결과, 본 연구에서 제안한 팔각 핑거 타입의 전극패턴을 갖는 LED 소자가 동일한 350 mA의 전류주입 하에서의 동작전압이 약 0.34 V 정도 감소되는 전기적 특성의 향상을 확인하였고, 광출력 또한 타 구조에 비하여 약 7.72 mW 정도 향상되는 광학적 특성을 확인하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.339-340
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• 2006

Recently, many researches have been done to improve optical performance of LCD-BLU(Back Light Unit). One of the most important parts in LCD-BLU is LGP(Light Guiding Plate). Micro-patterned LGP is known to have different optical characteristics depending on their shape, pattern density and size, etc. In the present study, a micro-optical patterned LGP mold was fabricated using LiGA process. The difference in the optical characteristics between positive and negative patterned LGP's was investigated by fixing the density, location and size of each pattern. It was found that the negative patterned LGP showed better optical characteristics than positive one.

• Fisheries and Aquatic Sciences
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• 제4권3호
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• pp.138-143
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• 2001

Red sea bream, Pagrus major a fish species characterized by its dualistic feeding pattern, was investigated to study the synchronizing effect of light and food on the demand-feeding rhythm. Nocturnal and diurnal red sea bream, both in groups and individually, were exposed to restricted-feeding and Light-Dark cycles of different periods. The phase relationship between both zeitgebers was also studied. In some cases, food availability restricted to the light or dark phase contrary to that of the previous feeding phase changed a diurnal feeding pattern into nocturnal and vice versa, suggesting that food can be one of the switching factors that decides whether the circadian system of red sea bream is diurnal or nocturnal. However, the fact that the feeding pattern of some fish was unrelated with the phase in which food was available suggests that other internal and/or external-factors could be involved in the temporal flexibility of red sea bream.

• 전기전자학회논문지
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• 제15권4호
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• pp.261-266
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• 2011

본 논문에서는 LED 가로등의 소비 전력을 줄이고 수명 및 LED 모듈의 열효율을 높이기 위한 효율적인 새로운 조명기기 LED 점등제어 시스템을 제안한다. 제안된 새로운 조명기기 점등제어 시스템은 조도를 측정하여 주변 조도에 따라 4단계로 구분하고 자동 패턴 조명 알고리즘을 적용한다. 그리고 단계검사를 통해 완전대칭을 형성하는 마방진 패턴에 교차점등 알고리즘을 적용하여 설정된 시간동안 점등을 하게 된다. 실험분석 결과, 기존의 조명 시스템과 비교하여 발열량과 소비전력이 최대 30%이상 감소되었고 LED의 수명이 최대 60%이상 향상되었기 때문에 LED 가로등에 적용할 경우 안정적이고 높은 에너지 효율성을 얻을 수 있다.

• 제어로봇시스템학회논문지
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• 제14권5호
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• pp.420-425
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• 2008

PMMA light guiding plate with nano-sized pattern was fabricated using anodized aluminum oxide membrane as a template for nano imprint lithography. Nano-sized pore arrays were prepared by the self-organization processes of the anodic oxidation using the aluminum plate with 99.999% purity. Since the aluminum plate has a rough surface, the aluminum plate with thickness of 1mm was anodized after the pre-treatments of chemical polishing, and electrochemical polishing. The surface morphology of the alumina obtained by the first anodization process was controlled by the concentration of electrochemical solution during the first anodization. The surface morphology of the alumina was also changed according to temperature of the solution during chemical polishing performed after first anodization. The pore widening process was employed for obtaining the one-channel with flat surface and height of the channel because the pores of the alumina membrane prepared by the fixed voltage method shows the structure of two-channel with rough surface. It is shown from SPM results that the nano-sized pattern on PMMA light guiding plate fabricated by nano imprint lithography method was well transferred from that of anodized aluminum oxide template.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2006년도 춘계학술대회 논문집
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• pp.95-98
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• 2006

LCD-BLU (Back Light Unit) is one of kernel parts of LCD unit. The fabrication method of a 3-D micro mold patterned with micro-lenses for the LGP (Light Guiding Plate), one of the most important parts of LCD-BLU, was presented. Instead of dot pattern made by etching, 3-D optical pattern design with $50{\mu}m$ micro-lens was applied in the present study. The micro-lens pattern fabricated by modified LiGA with thermal reflow process was applied to the optical design of LGP. The positive micro-lens patterned injection mold with different aspect ratios (i.e. 0.3 and 0.4) was fabricated with modified LiGA with thermal reflow process. The brightness of LCD-BLU increased as aspect ratio of micro-lens increased.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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• pp.269-272
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• 2008

LGP is a key component of LCD back light unit because it determines the brightness and sharpness of display image. Usually, it has optical patterns fabricated on the bottom surface. In the present paper the LiGA-reflow method was applied to fabricate the LGP mold. Furthermore, the optical simulation considering the replication ratio of pattern height was applied to the pattern design. The optical simulation through systematic correction scheme helped find the optimum distribution of pattern density. Finally, the stamper fabricated by this method was installed in the mold and LGP was produced by injection molding. As a result of luminance measurement for the final product, the average luminance and luminance uniformity was measured 3,180 nit and 84%, respectively. Consequently, the mold fabrication method using the LiGA-reflow and optical simulation(CAE) can save the expense and time compared with the existing fabrication methods(laser ablation and chemical etching).

• 전자공학회논문지
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• 제52권4호
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• pp.156-163
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• 2015

본 논문은 광패턴 조사를 통한 능동형 수위 및 거리 측정 기법을 제안한다. 기존 압력식, 부자식, 초음파식, 레이더식 등의 수위측정기법과 달리 최근에는 수위측정의 정확성과 모니터링 편리성을 강조한 영상기반 수위측정기법이 활용되고 있다. 본 논문에서는 참조용 광패턴을 교각이나 제방 등에 동적으로 조사(照射)하고, 카메라 장치로부터 조사된 광패턴 영상을 실시간 분석 처리하여 자동 수위측정 및 조사(照射) 대상물까지의 거리측정을 위한 새로운 방법을 제시한다. 기존 방법이 교각에 기(旣) 부착된 수위표나 마커 인식을 위해 수동적으로 영상데이터를 분석하는 것이었다면, 본 기법은 교각 설치 환경에 대응하여 능동적으로 참조 광패턴을 생성하여 사용함으로써, 난시야(難視野) 환경 및 잡음 대응에 효과적이고, 포터블 형태로 주야간 이용이 가능하며, 별도 조명 설치를 요구하지 않는 등의 강건한 수위 측정을 지원한다. 본 실험은 실내 시험 환경을 구성하여 시뮬레이션 하였으며, 0.4-1.4m 거리 13.5-32.5cm 높이에서 수위 및 거리 측정을 수행하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 춘계학술대회 논문집
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• pp.383-388
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• 1995

The ARC light has been measured using photo-detect system under different TIG welding condition. Light detect system consists of photo diode, ND Filter, OP Amp. A/D convertor and PC. The purpose of this experiment is to show the relationship between ARC light and process variables such as welding current, torch travel speed, etc. The results can be applied to estimate the condition of welding process and the quality of welding products. The signal of ARC light has periodic patterns in good TIG welding condition whereas in abnormal condition the signal has different pattern. Amount of Ar shielding gas and distance from electrode to specimen affect the signal pattern significantly.