• 한국정밀공학회지
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• 제21권11호
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• pp.163-170
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• 2004

In order to produce high-quality optical components, aspheric lenses have been widely applied in recent years. An aspheric lens consists of aspheric surfaces instead of spherical ones, which causes difficulty in the design process as well as the manufacturing procedure. Although injection molding is widely used to fabricate optical lenses owing to its high productivity, there remains lots of difficulty to determine appropriate mold design factors and injection molding parameters. In the injection molding fields, computer simulation has been effectively applied to analyze processes based on the shell analysis so far. Considering the geometry of optical lenses, however, numerical analysis based on solid elements has been reported as more reliable approach than shell -based one. The present work covers three-dimensional injection molding simulation using MP1/Flow3D and relevant deformation analysis of an injection molded plastic lens based on solid elements. Numerical analysis has been applied to the injection molding processes of an aspheric lens for a photo pick-up device. The reliability of the proposed approach has been verified in comparison with the experiments.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2020년도 제62차 하계학술대회논문집 28권2호
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• pp.423-424
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• 2020

다양한 환경 변화에 따라 적용 가능한 최적의 위장무늬 개발의 필요성이 증대됨에 따라 위장무늬 성능 평가를 위한 포토시뮬레이션 기술 또한 주목받고 있으나 포토시뮬레이션 저작에 관한 연구는 미비하다. 본 논문에서는 작전환경 이미지 상 위장무늬 이미지의 배치 및 기 배치된 위장무늬의 탐지 시간을 측정하는 소프트웨어인 포토시뮬레이션 기술 개발에 대해 서술한다. 개발된 포토시뮬레이션은 작전환경 및 위장무늬 이미지 로드, 사용자 입력도구를 통한 대상 작전환경 이미지 상 위장무늬 이미지의 배치 및 저작, 저작 된 작전 환경 이미지 상 위장무늬 이미지를 모니터에 출력, 사용자 입력도구를 통한 작전환경 이미지 상 위장무늬 이미지의 탐지 및 탐지 시간 측정 기술을 포함한다. 결과에서는 개발 포토시뮬레이션 기술을 통한 위장무늬 이미지 배치 및 저작, 그리고 위장무늬 이미지의 평균 시간 측정 결과 예시를 보여준다.

• 반도체디스플레이기술학회지
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• 제16권1호
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• pp.65-69
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• 2017

This paper presents a Technology-CAD (TCAD) simulation of the characteristics of crystalline Si pillar array solar cells. The junction depth and the surface concentration of the solar cells were optimized to obtain the targeted sheet resistance of the emitter region. The diffusion model was determined by calibrating the emitter doping profile of the microscale silicon pillars. The dimension parameters determining the pillar shape, such as width, height, and spacing were varied within a simulation window from ${\sim}2{\mu}m$ to $5{\mu}m$. The simulation showed that increasing pillar width (or diameter) and spacing resulted in the decrease of current density due to surface area loss, light trapping loss, and high reflectance. Although increasing pillar height might improve the chances of light trapping, the recombination loss due to the increase in the carrier's transfer length canceled out the positive effect to the photo-generation component of the current. The silicon pillars were experimentally formed by photoresist patterning and electroless etching. The laboratory results of a fabricated Si pillar solar cell showed the efficiency and the fill factor to be close to the simulation results.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2007년도 춘계학술발표회 논문집
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• pp.333-336
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• 2007

This paper is the environmental impact assessment of at road design in the light of the sense for the real from the virtual reality. For in this papers, This study developed 3D-model and virtual reality contents by suggesting the environmental impact assessment based on GIS in the road design. And, through this process, it's possible to visualize the environmental impact assessment by constructing the 3D-model and simulation. The 3D-model can be a method to show the road effectively by maximizing the road's shape visually after the construction. The main construction which composes polyhedron model that is generated from digital map and aerial photo is built by mapping the real texture, so the Sense for the Real was more heightened. Through this study, it must be made to shorten a long time exhausting period of conference and construct more real road after due scene consideration by specific and various low-cost strategy in the environmental impact assessment afterwards.

• 한국생산제조학회지
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• 제21권2호
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• pp.311-315
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• 2012

Diaphragm type noncontact automatic control valve is a valve for controling acidic PR(Photo Resist) liquid used in the semiconductor process. PR is photosensitive liquid that changes phases depending on light transmittance. PR is very toxic and expensive; the purpose of this paper is to address methods that prevent loss due to leaks. The design of noncontact precise automatic control valve is expected to play an important role in controlling fluid flow, therefore influencing energy conservation and environmental improvement. In this paper, diaphragm type automatic control valve's part design, assembly and simulation are introduced. Also, through the analysis of fluid flow the valve's internal velocity, pressure, and turbulent intensity are interpreted. This paper proposes to contribute to the improvement of the valve's performance.

• Journal of the Optical Society of Korea
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• 제15권4호
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• pp.357-361
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• 2011

Photon-counting sensing is a widely used technique for low-light-level imaging applications. This paper proposes a distance information extraction method with photon-counting passive sensing under low-lightlevel conditions. The photo-counting passive sensing combined with integral imaging generates a photon-limited elemental image array. Maximum-likelihood estimation (MLE) is used to reconstruct the photon-limited image at certain depth levels. The distance information is extracted at the depth level that minimizes the sum of the standard deviation of the corresponding photo-events in the elemental image array. Experimental and simulation results confirm that the proposed method can extract the distance information of the object under low-light-level conditions.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.500-503
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• 2002

In this paper, we demonstrate the deformation of TFT-LCD panel using numerical analysis based on the finite element method. To make better uniform cell gap and less stress at a photo-definable spacer (spacer), we have investigated process and design factors such as amount of liquid crystal (LC), spacer density, area, height, and material property. Furthermore we optimized design factors and achieved the robust design through the simulation.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.395-395
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• 2011

일반적으로 태양전지에서 anti-reflection layer는 조사되는 태양 광을 좀 더 많이 사용하기 위하여 nitride나 oxide와 같은 막을 표면에 형성한다. 본 연구는 이 anti-reflection으로 사용되는 nitride와 oxide의 각각의 두께와 굴절률 변화에 따른 특성변화를 SILVACO를 이용하여 전산모사하고 그 특성변화를 분석하였다. Anti-reflection layer가 없을 경우에는 조사된 빛에 따른 available photo current 활용이 낮았으며, 특히 그 경향은 단파장영역에서 두드러지게 나타났다. 따라서 anti-reflection layer의 최적화를 위해서 두께를 가변하여 available photo current를 분석하였으며, 각 물질의 굴절률 변화 및 이중층 구조의 anti-reflection layer를 형성하고 특성변화를 분석함으로써 최적화하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.6-8
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• 1994

Switched reluctance motor drive system is well known as a variable speed drive system because it has a simple motor structure and a simple driving circuit. Widely slotted photo interrupter has been investigated as a position sensor for SRM speed control because it has advantages of low cost and simple structure. However it has low resolution and it produces dead-time signal. This paper studies variable speed SRM drive system with slotted photo-interrupter. Controller in this study is constructed by using fuzzy controller that covers system nonlinearities and small perturbations in sufficiency. The performance of this system is evaluated through computer simulation and experiment results.

• 제어로봇시스템학회논문지
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• 제12권11호
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• pp.1095-1101
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• 2006

The clean tube system was developed as a means of transferring air-floated wafers inside a closed tube filled with super clean air. This paper presents a wafer position sensing method in the clean tube system, where the photo proximity sensors are used. The first presented method uses the two positions sensed lately in order to compute the wafer center position. The next method uses the latest sensed position and the next latest position compensated with the information of the wafer velocity. The third method uses the kalman filter, which enable us to use all the previous sensing information. The simulation results are compared to show results of the presented method. In addition, the paper presents a control method to stop the wafer at the center of the unit in the clean tube system. The experimental clean tube system worked successfully with the applying the both presented methods of sensing and control.