• Journal of the Optical Society of Korea
• /
• 제20권1호
• /
• pp.180-187
• /
• 2016

The independent operation of a color filter for incident polarization is demonstrated using a guided-mode resonance (GMR) filter employing a metal-insulator-metal (MIM) waveguide. To achieve independent operation, a rectangular MIM grating is proposed as a wave-guide resonator. The design considerations are discussed and include how to determine the grating period and slit width. Power flow distribution is observed with slit width variation. Blue-green, green-red, and blue-red filters for corresponding x- and y-polarizations are demonstrated as application examples with numerical simulation with rectangle-shaped MIM grating. As a practical application, feasibility as a chromatic polarizer is discussed.

• Design & Manufacturing
• /
• 제10권3호
• /
• pp.8-13
• /
• 2016

Despite technological advance, there have been several troubles in photo reaction injection molding (photo RIM) to produce ultra thin light guide panels (LGPs). In this study, micro leakage problem at cavity edge during photo RIM was investigated numerically. In order to obtain optimal processing conditions, we regulated inlet pressure of injected resin at the cavity edge and figured out micro leakage behaviors. At low inlet pressure (less than 100 Pa), though the micro leakage problem was not occurred, another problem, short shot due to not enough driving force, was appeared More than 1,000 Pa of the inlet pressure, injected resin was rapidly leaked through the micro gap at the cavity edge. Finally, we obtained optimal inlet pressure around 600 ~ 1,000 Pa. At this region, injected resin fully filled the cavity without micro leakage behavior. Based on the present study, further comparative investigations with experimental photo RIM should be performed to find optimal processing conditions for produce ultra thin LGPs.

• 한국방송∙미디어공학회:학술대회논문집
• /
• 한국방송공학회 2015년도 하계학술대회
• /
• pp.486-488
• /
• 2015

FSC(Field Sequential Color) LCD has high efficiency, high brightness and color saturation due to 3 times aperture larger than conventional LCD. However it is well known that color break-up (CBU) and color interference are hot issue need to be solved. We propose a novel sequential driving method with edge-lit light guide composed of $16{\times}15$ blocks to reduce CBU and color interference. The experimental results show not only suppression of CBU but also the side effects are minimized.

• International Journal of Contents
• /
• 제2권1호
• /
• pp.39-44
• /
• 2006

Load sharing is a critical resource in computer system. In sender-initiated load sharing algorithms, the sender continues to send unnecessary request messages for load transfer until a receiver is found while the system load is heavy. Meanwhile, in the receiver initiated load sharing algorithms, the receiver continues to send an unnecessary request message for load acquisition until a sender is found while the system load is light. These unnecessary request messages result in inefficient communications, low CPU utilization, and low system throughput in distributed systems. To solve these problems, we propose a genetic algorithm based approach for improved sender-initiated and receiver-initiated load sharing in distributed systems. And we expand this algorithm to an adaptive load sharing algorithm. Compared with the conventional sender-initiated and receiver-initiated algorithms, the proposed algorithm decreases the response time and task processing time.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2006년도 춘계학술대회 논문집
• /
• pp.533-534
• /
• 2006

Micro pyramid pattern and its array are designed to enhance the brightness and its uniformity of LGP which is one of key parts in LCD. The designed micro pyramid patterns are fabricated on a Si-wafer first through MEMS process and then a Ni-stamper is electro-plated from the Si pattern master. Adopting the fabricated Ni-stamper, LGPs are injection molded at different mold temperatures and the fidelity of the pattern replication is estimated for each molding conditions and pattern locations. The replicated patterns are found to have some defect such as local short shot or micro weld line which are believed to have negative effect on the performance of the LGP.

• 한국산학기술학회:학술대회논문집
• /
• 한국산학기술학회 2008년도 추계학술발표논문집
• /
• pp.358-361
• /
• 2008

본 논문에서는 열화상촬영기 및 온도분포 해석 프로그램을 이용하여 금형가열온도와 실제 금형온도의 온도편차를 비교하여 금형가열 시 Stamper 표면의 온도분포를 해석하였다. 또한 전열가열방식(E-MOLD)을 이용하여 복합기능 도광판(Prismless LGP)을 제조하였고, 금형온도에 따른 복합기능 도광판(Prismless LGP)의 광특성 평가를 하였다. 그 결과 금형온도가 증가할수록 패턴 전사성 향상으로 인해 휘도 또한 증가하였고, 특히 유리전이온도($140^{\circ}C$) 이상에서 크게 상승하였다.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2004년도 춘계학술대회 논문요약집
• /
• pp.232-232
• /
• 2004

최근 초고속 광통신 시스템이 발달함에 따라, 광통신 시스템 및 초고속 광통신 시스템의 핵심 부품인 평면도파로형 분배기(Splitter) 및 결합기(Coupler), 파장분할 다중화소자(WDM), AWG(Arrayed Wave Guide) 필터와 같은 소자부품 수요가 급격히 늘고 있다. 그러나 이러한 소자를 생산하는 공정은 수공적인 방법에 의존하여 생산성 향상을 위한 자동화에 대한 요구가 시급하다 특히 소자(Devices)와 광섬유(Optical fiber) 사이의 광학적인 정렬(Alignment)과 접속(Attachment) 공정은 부품 성능 및 생산성 향상, 그리고 비용절감을 위한 가장 핵심적인 문제로 대두되고 있다.(중략)

• 한국분말재료학회지
• /
• 제25권2호
• /
• pp.170-177
• /
• 2018

Colloidally synthesized luminescent nanocrystals (NCs) have attracted tremendous attention due to their unique nanoscale optical and electronic properties. The emission properties of these NCs can be precisely tuned by controlling their size, shape, and composition as well as by introducing appropriate dopant impurities. Nowadays, these NCs are actively utilized for various applications such as optoelectronic devices including light emitting diodes (LEDs), lasers, and solar cells, and bio-medical applications such as imaging agents and bio-sensors. In this review, we classify luminescent nanomaterials into quantum dots (QDs), upconversion nanoparticles (UCNPs), and perovskite NCs and present their intrinsic emission mechanism. Furthermore, the recently emerging issues of efficiency, toxicity, and durability in these materials are discussed for better understanding of industry demands. As well, the future outlook will be offered for researchers to guide the direction of future research.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
• /
• pp.1083-1084
• /
• 2006

The wide spread of DC electric railway systems such as urban rapid transits including heavy rail and light rail transits has significant ramification as the stray currents from return conductor rails can cause the electrochemical interference, that is, the electrolytic corrosion of both rails and outside underground metallic infrastructures. The immature understanding of either the railway authority who is responsible for establishing the necessary provisions at the design stage or the affected parties makes it difficult to prepare the optimum range of solutions for the long-pending interference problem. In Japan, however, numerous assessment studies have been carried out on the stray current interference, by which protective guidelines are provided by "Electrolysis Committee". In this paper, we review a guide book from "Tokyo Electrolysis Committee", namely, "Protective Methods for Stray Current Corrosion".

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2008년도 춘계학술대회 논문집
• /
• pp.519-534
• /
• 2008

The Maglev travels at levitated status from the rail in some gab (about $8\sim10mm$). it make difference with the existing subway or the another LRV. The detection method of the train speed and the train position to be used at Maglev's signaling system differ with the existing subway or the another LRV's. so, the signal system construction of the new method is necessary. This paper describes the configuration and characteristic of the total signaling system (TTC/Wayside/Cab/Guide way system etc.) developed for Maglev, and the design concept of the signaling system based on the latest wireless LAN communication for driverless operation.