• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1386-1389
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• 2008

Conventional viewing angle switching electrode requires pixel division and additional liquid crystal panel. Hence the conventional viewing angle switching has low aperture ratio and high thickness. In this paper we proposed new viewing angle switching using hybrid aligned nematic mode by fringe-field electrode field (named HAN-FFS) with single liquid crystal panel. The fringe-field switching electrode is located at the bottom, and the additional common electrode is located at the top of the cell to control viewing angle. The proposed device is free from additional liquid crystal panel and pixel division. Consequently, the suggested structure has not only high aperture ratio but also show an excellent potential for viewing angle switching.

• Current Optics and Photonics
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• v.5 no.3
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• pp.229-237
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• 2021

The capabilities of the near-field scanning optical microscope (NSOM) for obtaining high resolution lateral topographical images as well as for mapping the spectroscopic and optical properties of a sample below the diffraction limit of light have made it an attractive research field for most researchers dealing with optical characteristics of materials in nano scales. The apertured NSOM technique involves confining light into an aperture of sub-wavelength size and using it to illuminate a sample maintained at a distance equal to a fraction of the sub-wavelength aperture (near-field region). In this article, we present a setup for developing NSOM using a cantilever with a sub-wavelength aperture at the tip. A single laser is used for both cantilever deflection measurement and near-field sample excitation. The laser beam is focused at the apex of the cantilever where a portion of the beam is reflected and the other portion goes through the aperture and causes local near-field optical excitation of the sample, which is then raster scanned in the near-field region. The reflected beam is used for an optical beam deflection technique that yields topographical images by controlling the probe-sample in nano-distance. The fluorescence emissions signal is detected in far-field by the help of a silicon avalanche photodiode. The images obtained using this method show a good correlation between the topographical image and the mapping of the fluorescence emissions.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.81-82
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• 2005

새로운 고 용량 광 저장 시스템 개발을 위하여 초 미세 개구를 가지는 마이크로 프로브 어레이시스템 완성을 목표로 연구를 진행하였다. 효율적인 초 미세 개구 생성을 위해 기존의 제작된 마이크로 프로브 위에 FIB 공정을 이용하여 40nm 크기를 가지는 어퍼쳐를 만들었다. 나노 어퍼쳐를 가지는 마이크로 프로브 어레이는 곧 마이크로 렌즈와 VCSEL 과 일체화된 광 기록 헤드시스템으로 준비될 예정이다. 멤스 공정을 이용한 이 시스템은 향후 높은 저장 용량과 빠른 전송속도를 달성할 수 있는 차세대 광정보저장기기에 적용 가능한 새로운 광 픽업 시스템을 발전시킬 수 있을 것으로 생각된다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.507-508
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• 2010

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.393-394
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• 2009

• Proceedings of the Optical Society of Korea Conference
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• 2005.02a
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• pp.154-155
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• 2005

• Proceedings of the Optical Society of Korea Conference
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• 2008.02a
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• pp.343-344
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• 2008

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.7
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• pp.739-744
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• 2012

The genetic algorithm (GA) is regarded as one of the best ways for determining a global solution. Because it does not require calculating the design sensitivity differently from the ordinary gradient-based method, it is appropriate for the design problem in the ultra-high frequency range; the ordinary gradient-based method has difficulty in calculating the sensitivity in this range. This paper deals with nano-aperture grating topology optimization based on the GA and the ON/OFF method. The objective of this study is to maximize the transmittance in the measuring area. The simulation and optimization processes are carried out by using the commercial package COMSOL associated with Matlab programming. The final optimal design gives around 21% performance improvement, compared with the initial model.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.10 s.253
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• pp.1314-1319
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• 2006

This paper describes the novel fabrication method of the high-aspect-ratio nano structure which is impossible by conventional method using a shadow mask and a Deep X-ray Lithography (DXRL). The shadow mask with $1{\mu}m-sized$ apertures is fabricated on the silicon membrane using a conventional UV-lithography. The size of aperture is reduced to 200nm by accumulated low stress silicon nitride using a LPCVD (low pressure chemical vapor deposition) process. The X-ray mask is fabricated by depositing absorber layer (Au, $3{\mu}m$) on the back side of nano shadow mask. The thickness of an absorber layer must deposit dozens micrometers to obtain contrast more than 100 for a conventional DXRL process. The thickness of $3{\mu}m-absorber$ layer can get sufficient contrast using a central beam stop method, blocking high energy X-rays. The nano circle and nano line, 200nm in diameter in width, respectively, were demonstrated 700nm in height with a negative photoresist of SU-8.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.698-701
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• 2005

We have investigated experimentally a nano patterning using electron beam lithography for the nickel stamper fabrication. Recently, DVD and Blu-ray disk(BD) have nano-scale patterns in order to increase the storage density. Specially, BD has 100nm-scale patterns which are generally fabricated by electron beam lithography. In this paper, we found optimum condition of electron-beam lithography for 100nm-scale patterning. We controlled various conditions of EHP(acceleration voltage), beam current, dose and aperture size in order to obtain optimum conditions. We used 100nm-thick PMMA layer on a silicon wafer as photoresist. We found that EHP was the most dominant factor in electron-beam lithography.