• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1841-1844
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• 2005

A linear motor makes a long stroke by accumulating short steps, which is based on the quasistatic deformation of a magnetostrictive material in a magnetic field. It's also called as inchworm effect. The application areas of linear motors are an adaptive and active optics, X-Y positioning, precision alignment, etc. It is found that control of the frequency and current inputs are all that is necessary to control the speed handling ability of the linear motor. In inchworm mode, linear speeds of up to $500{\mu}m/s$ are achieved resulting from the accumulation of $25{\mu}m$ steps at 1.4A.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.403-404
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• 2007

Compound eyes in nature present intriguing topics in physiological optics due to their unique optical scheme for imaging. For example, a bee's eye has thousands of integrated photonic units called ommatidia spherically arranged along a curvilinear surface so that each unit points in a different direction. The omni-directionally arranged ommatidium collects incident light with a narrow range of angular acceptance and independently contributes to the capability of wide field-of-view (FOV) detection. Artificial implementation of compound eyes has attracted a great deal of research interest because the wide FOV exhibits a huge potential for medical, industrial, and military applications. So far, imaging with a FOV over $90^{\circ}$ has been achieved only with fisheye lenses which rely on bulky and expensive multiple lenses and require stringent alignment. In this talk, we will discuss about the spherical 3D arrangement of the photonic structures of biologically inspired artificial compound eyes in a small form-factor to have and the functional and anatomical similiarity with natural compound eyes.

• International Journal of Precision Engineering and Manufacturing
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• 제7권3호
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• pp.60-65
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• 2006

This paper proposes a new type of six degree-of-freedom fine positioner that can be used to align the condenser in X-ray microscopy precisely. The new concept was based on the requirements for an X-ray microscope. A proposed modeling method was used to obtain an optimal design, which was verified with a finite element analysis. The fine positioner was then constructed and an experiment was used to validate its performance.

• 동력기계공학회지
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• 제10권2호
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• pp.99-103
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• 2006

The laser interferometer has been used for measurement of the micro displacement error. Although the laser interferometer is widely accepted as a tool for measurement of motion accuracy, the set-up procedure is time-consuming because of the strict requirement on alignment between a laser head and optic units. This paper addresses the development of a laser interferometer to measure the micro displacement for a micro machine. The portable laser interferometer which integrates a laser probe and optics, is developed for the convenient measurement. For the experiment, moving mirror set up on the micro stage. The velocity decoding board is also added to calculate doppler shift frequency directly. The output signal is obtained and analyzed by LabView. Finally experiments are found out the relation between micro displacement and output signal.

• 대한기계학회논문집A
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• 제30권12호
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• pp.1649-1657
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• 2006

Fizeau interferometer is well known optical instrument for measuring the lens profile accurately. The object of this study is focused on the design and optical measuring techniques for large optical components, such as a reflection mirror for astronomical purpose. Measuring of large optical lens, the object could not be moved as small one but the measuring instrument must be moved for the alignment, because of the geometric conditions and the accuracy of the stage. Therefore, a five axis stage is designed to align the Interferometer instead of the measuring object. This instrument will be used for an on machine measuring system in polishing machine for large optical lens.

• 한국광학회지
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• 제11권3호
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• pp.179-186
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• 2000

초고속정보통신망을 구성하는 교환기(ATM system)과 전송부문(B-NT(Broadband Network Termination) system, 10G 전송system 등)에 사용할 수 있는 155Mbps 수동 광정렬 방식의 광수신 모듈의 광결합 효율과 정렬오차 허용도를 게산하고 이를 적용한 엔지니어링 샘플로부터 이론치 비교와 flat-광섬유를 이용한 butt 커플링 패키지 방법으로 최대 -4.5dBm 광출력을 갖는 광송신기 제작 및 신뢰성 검사로 값싼 광송신기 제작에 대하여 알아보았다.

• 한국광학회지
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• 제8권6호
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• pp.456-460
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• 1997

링 레이저 공진기를 광학적으로 정렬하는 방법은 여러 가지가 있지만, 투과광 스펙트럼 측정법(cavity transmission spectrum control)은 측정이 매우 간단하고 공진기의 손실을 측정하면서 동시에 정렬을 할 수 있는 장점이 있다. 투과광 스펙트럼 측정법을 이용한 공진기의 광학적 정렬 장치를 구성하여, 레이저 자이로스코프에 사용할 링형 공진기에 모두 네 개의 반사경을 정렬 부착시켰으며, 동시에 정렬한 공진기의 내부 손실 값을 측정했다. 그 결과 최소 내부 손실은 0.98%였으며, 네 개의 반사경에 대한 총 반사 계수는 99.02%로 계산된다.

• Bulletin of the Korean Chemical Society
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• 제30권4호
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• pp.882-886
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• 2009

The electrode contact poling is one of the efficient tools to induce a stable polar order of nonlinear optical (NLO) chromophores in the solid film. Self-assembled NLO chromophores with high electro-optic (E-O) activities were utilized for quantitative determination of the chromophore order induced under contact poling by spectroscopic changes. We found that NLO chromophores rarely decompose under the high electric field during contact poling. The absorption spectra were de-convoluted into a sum of Gaussian components to separate energy transitions for a binary composite system which contains a secondary guest chromophore AJC146 in the self-assembled chromophore HDFD. Poling efficiency was significantly improved in the binary system compared to the individual components.

• 한국광학회지
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• 제9권2호
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• pp.117-122
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• 1998

쌍안정 TN LCD의 스위칭 특성을 Berreman에 의해 제시된 backflow를 고려한 이론적 모델을 적용하여 해석하였다. 그리고 이 모델을 적용하여 $180^{\circ}$ 쌍안정 TN 액정셀이 쌍안정 특성을 갖기 위해서는 두 유리기판을 서로 반대 방향으로 러빙해야 하고 d/p도 중요한 요소임을 확인하였다.

• 천문학회보
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• 제46권2호
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• pp.56.1-56.1
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• 2021

표준우주모형이 예측하는 천체의 성장 역사를 추적하기 위해서는 보통의 밤하늘 밝기보다 약 1000배 어두운 낮은 표면밝기(Low Surface Brightness, LSB) 우주 탐사가 필요하지만, 관측기술의 한계로 아직 LSB 우주는 거의 미지의 세계에 있다고 할 수 있다. 한국천문연구원에서는 LSB 천체 관측에 최적화된 직경 300 mm K-DRIFT Pathfinder 망원경을 개발하였다. LSB 천체는 ~28 mag/arcsec2 보다 어두운 천체로 표면밝기가 매우 낮기 때문에 망원경 내부의 미광(stray light)을 최소화하는 것이 중요하다. 이를 구현하기 위해 K-DRIFT Pathfinder 망원경에는 선형 비점수차가 제거된 비축 자유곡면 삼 반사경 형태를 적용하였다. 본 연구를 통해 가시광 영역에서 선형 비점수차가 제거된 비축 자유곡면 삼 반사 망원경의 설계, 제작 및 측정 가능성을 검증하였다. 본 발표에서는 K-DRIFT Pathfinder 망원경에 적용된 비축 자유곡면 광학면의 가공, 삼 반사 망원경의 조립 및 정렬 결과를 소개한다.