• 한국군사과학기술학회지
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• 제24권3호
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• pp.309-316
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• 2021

In this paper, the electrical power output of the micro-combustor thermophotovoltiac(TPV) system was analyzed. The system consists of a micro-combustor, photonic crystals(PhCs), and photovoltaic cells(PV cells). The system has a micro-combustor that can achieve over 1,000 K surface temperature by consuming 2.5 g/h hydrogen fuel. Also, this system incorporates current state-of-the-art PhCs surfaces(2D Ta PhCs and Tandem Filter) to increase electrical power output. In addition, InGaAsSb PV cell, which bandgap is 0.55 eV, was applied to convert a wide range of radiative energy. The performance analysis shows that a single micro-combustor TPV system can produce 0.4 W ~ 27.7 W electrical power with the temperature change of emitter(900 K ~ 1,500 K) and PV cell(250 K ~ 400 K).

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.939-942
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• 2004

In this study, we report simulation results of single-panel LCOS (liquid crystal on silicon). Reflective LCOS microdisplays are widely used in various projection and near-eye application. For one panel system, liquid crystal response time is an important variable. The panel must switch fast enough to support the display of Field color sequential with high field rates. In order to have fast response and good contrast, a vertical alignment (VA) cell was used in this study. With suitable selection on LC parameters like temperature, viscosity, elastic constant and birefringence, it is possible to get response time of around 2ms from a 2.0 um-thick vertical alignment cell. This result also indicates an ease of production control on 2.0 um cells than 1.0 um cells.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1999년도 PROCEEDINGS OF 99 INTERNATIONAL CONFERENCE OF THE KACG AND 6TH KOREA·JAPAN EMG SYMPOSIUM (ELECTRONIC MATERIALS GROWTH SYMPOSIUM), HANYANG UNIVERSITY, SEOUL, 06월 09일 JUNE 1999
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• pp.403-418
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• 1999

Fiber growth of Al2O3/R-Al-O(R=Y, Gd, Dy, Ho, Er) eutectic by the micro-pulling down methods is described. The thermal stability and strength at elevated temperature of each material is evaluated in relation to the microstructure. PACS: 81.05 Mh, 81.10 Fq, 81.30-t.

• Journal of Information Display
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• 제7권2호
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• pp.12-15
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• 2006

We propose a patterning method of liquid crystal (LC) alignment layer for producing multi-domain LC structures. By controlling thermal conditions during micro-contact printing procedures and facilitating wetting properties of patterning materials, patterned LC orientation can be easily obtained on a bare ITO surface or other polymer films. The newly proposed patterning method is expected to be a very useful tool for fabricating multi-domain LC structures to enhance or design electro-optic properties of LC-based devices.

• 한국기계가공학회지
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• 제11권5호
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• pp.76-81
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• 2012

The continuing demand for increasingly slimmer and brighter liquid crystal display(LCD) panels has led to an increased focus on the role of the light guide panels(LGPs) or optical films that are used to obtain diffuse, uniform light from the backlight unit(BLU). And the most basic process in the production of such BLU components is the micromachining. LCD BLUs comprise various optical elements such as a LGP, diffuser sheet, prism sheet, and protector sheet with micro patterns. 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 feasibility in microcutting various aspect ratio patterns on electroless nickel plated die materials when using single-crystal diamond tools. Cutting performance was evaluated at various cutting speeds and depths of cut using different machining methods and machine tools.

• 한국재료학회지
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• 제27권12호
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• pp.679-687
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• 2017

A strain-gradient crystal plasticity finite element method(SGCP-FEM) was utilized to simulate the compressive deformation behaviors of single-slip, (111)[$10{\bar{1}}$], oriented FCC single-crystal micro-pillars with two different slip-plane inclination angles, $36.3^{\circ}$ and $48.7^{\circ}$, and the simulation results were compared with those from conventional crystal plasticity finite element method(CP-FEM) simulations. For the low slip-plane inclination angle, a macroscopic diagonal shear band formed along the primary slip direction in both the CP- and SGCP-FEM simulations. However, this shear deformation was limited in the SGCP-FEM, mainly due to the increased slip resistance caused by local strain gradients, which also resulted in strain hardening in the simulated flow curves. The development of a secondly active slip system was altered in the SGCP-FEM, compared to the CP-FEM, for the low slip-plane inclination angle. The shear deformation controlled by the SGCP-FEM reduced the overall crystal rotation of the micro-pillar and limited the evolution of the primary slip system, even at 10 % compression.

• Journal of Information Display
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• 제6권2호
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• pp.1-6
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• 2005

We demonstrated stability-enhanced liquid crystal (LC) displays using pixel-isolated LC mode in which LC molecules are isolated in pixel by horizontal polymer layer and vertical polymer wall. The device shows good electro-optic properties against external point or bending pressure due to the polymer structures. The polymer wall acts as supporting structure from mechanical pressure and prevents the cell gap from bending. Moreover, the polymer layer acts as an adhesive to ensure a tight attachment of the two substrates. We present herein various methods for producing polymer structures by using an anisotropic phase separation from LC and polymer composites or patterned micro-structures for stable flexible liquid crystal displays.

• 한국세라믹학회지
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• 제34권8호
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• pp.834-842
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• 1997

Controlled Ca impurity implanted inner crack-like pore in the high purity alumina single crystal, sapphire, had been created by micro-fabrication technique, which includes ion implantation, photo-lithography, Ar ion milling, and hot press technique. The morphological change and the healing of cracklike pore in Ca doped high purity single crystal alumina, sapphire, during high temperature heat treatment in vacuum were observed using optical microscopy. The dot-like surface roughening was developed and hexagon like crystal appeared on inner surface of crack-like pore after heat treatment. Bar type crystals, probably CaO.6Al2O3, were observed on the inner surface after 1 hour heat treatment at 1, 50$0^{\circ}C$, but this bar type crystal disappeared after 1 hour heat treatment at 1, $600^{\circ}C$. This disappearance means that there should be a little increase of Ca solubility limit to alumina at this temperatures.

• 한국컴퓨터정보학회논문지
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• 제8권2호
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• pp.57-63
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• 2003

본 논문에서는 최근 대두되고 있는 마이크로 디스플레이 디바이스 LCOS(Liquid Crystal On Silicon)에 대하여 간단히 논하며, 출력 해상도가 물리적으로 고정되어 있어 다양한 영상 모드를 변환해주는 스케일 변환기(scale converter)와 그레이 스케일(Gray scale)이 바탕인 LCOS 마이크로 디스플레이 디바이스에서 컬러(color) 구현을 위한 하드웨어 구조와 본 디스플레이 구동 시스템을 구현한 ASIC에 대한 구조에 대하여 논하고자 한다

• 전기학회논문지
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• 제60권4호
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• pp.817-822
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• 2011

We propose a novel ring structure based on the stadium-shaped ring resonator (SSRR) with dual photonic crystal microcavity (DPCM) for biosensor and analyzed the sensing characteristics. The Q-factor of the photonic crystal microcavity (PCM) can be significantly enhanced when the PCM or DPCM has the same resonance condition as the SSRR. The simulation results show that the Q-factor of the SRR with DPCM was increased by three times in comparison with single PCM structure. We also defined a mutual interference between two PCMs. Assuming a detectable spectral resolution of 10 picometers, a refractive index resolution of $3.03\times10-5$ can be measured on the SSRR-DPCM.