• 한국기계가공학회지
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• 제13권5호
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• pp.64-69
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• 2014

This article presents machining experiments to assess the relationship between the profile accuracy and the workpiece hardness using a natural diamond tool on an ultra-precision diamond turning machine. The study is intended to secure a corner cube prism pattern for reflective film capable of high-quality outcomes. The optical performance levels and edge images of corner cubes having various hardness levels of the copper-coated layer on a carbon steel plate are analyzed. The hardness of the workpiece has a considerable effect on the profile accuracy. The higher the hardness of the workpiece, the better the profile accuracy and the worse the edge wear of the diamond tool.

• 한국기계가공학회지
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• 제15권3호
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• pp.109-114
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• 2016

This study presents the optimal hardness range for a coated layer of a workpiece when the diamond tool cuts the corner-cube pattern on the coated plates using an ultra-precision diamond-turning machine. Two kinds of coated plates, which have the hardness range of 211~328 Vickers hardness, are used on the first experiments. The form accuracy for the corner-cube pattern could be achieved through the following experiments using the accumulated thin copper plates in second experiments, having optimal 265~275 Vickers hardness based on the basic first experiments without tool wear. When the number of machining adjustments was increased to seven times, having machining depth was reduced successively in second experiment, a fine surface could be achieved without tool wear.

• 한국광학회지
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• 제26권1호
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• pp.17-22
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• 2015

재귀 반사체(Retro Reflector)는 그 반사특성을 살려 베네치안 블라인드 슬랏, 디스플레이, 그리고 교통 안전 분야 등에서 활용 영역이 넓어져 가고 있다. 재귀 반사율 분포를 조절할 수 있는 코너 큐브 재귀 반사체를 정의하고, 입사각도에 따라 그 재귀반사광의 특성을 분석하여 교통 안전 분야에 적용하고자 하였다. 특성 분석 결과를 용이하게 파악할 수 있도록 시각화한 특성 도표를 고안하였으며, 이를 이용하여 다양한 교통 안전 분야의 재귀 반사 시트를 정량적으로 설계할 수 있음을 보였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.755-759
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• 2004

The van Cittert-Zernike theorem has been used in radio astronomy. Recently, the van Cittert-Zernike theorem has been tried to 3D source reconstruction. A couple of interferometer has been used in 3D coherence imaging like Michelson Stellar Interferometer and Rotational Shearing Interferometer. We propose a new type of interferometer, which is a wavefront folding interferometer with a corner cube. By characteristics of the corner cube, it is capable of measuring both mutual intensity and cross spectral density function, and it is very easy to align and robust to disturbance. We simulate the feasibility of this interferometer setup by simulation of point source reconstruction.

• 한국항공우주학회지
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• 제36권1호
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• pp.92-99
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• 2008

다목적실용위성5호는 정밀궤도결정을 위하여 위성레이저반사경을 부착할 예정이다. 레이저반사경은 독일 DFZ에서 개발된 것으로 4개의 코너큐브로 구성된 피라미드 형태를 갖는다. 본 논문에서는 레이저반사경의 유효면적과 link budget에 따른 광자수 계산 및 지상관측소 위치에 따른 광자수 계산 등의 성능 해석을 수행하였다.

• 한국광학회:학술대회논문집
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• 한국광학회 2007년도 동계학술발표회 논문집
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• pp.231-232
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• 2007

• Journal of Electrical Engineering and Technology
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• 제5권2호
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• pp.337-341
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• 2010

In this paper, an extremely low voltage operated micro corner cube retroreflector (CCR) was fabricated for free-space optical communication applications by using bulk silicon micromachining technologies. The CCR was comprised of an orthogonal vertical mirror and a horizontal actuated mirror. For low voltage operation, the horizontal actuated mirror was designed with two PZT cantilever actuators, torsional bars, hinges, and a mirror plate with a size of $400{\mu}m{\times}400{\mu}m$. In particular, the torsional bars and hinges were carefully simulated and designed to secure the flatness of the mirror plate by using a finite element method (FEM) simulator. The measured tilting angle was approximately $2^{\circ}$ at the applied voltage of 5 V. An orthogonal vertical mirror with an extremely smooth surface texture was fabricated using KOH wet etching and a double-SOI (silicon-on-insulator) wafer with a (110) silicon wafer. The fabricated orthogonal vertical mirror was comprised of four pairs of two mutually orthogonal flat mirrors with $400{\mu}m4 (length) $\times400{\mu}m$ (height) $\times30{\mu}m$ (thickness). The cross angles and surface roughness of the orthogonal vertical mirror were orthogonal, almost $90^{\circ}$ and 3.523 nm rms, respectively. The proposed CCR was completed by combining the orthogonal vertical and horizontal actuated mirrors. Data transmission and modulation at a frequency of 10 Hz was successfully demonstrated using the fabricated CCR at a distance of approximately 50 cm.

• 한국항공우주학회지
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• 제35권12호
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• pp.1135-1142
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• 2007

과학기술위성2호는 정밀궤도결정을 위하여 위성레이저반사경을 부착할 예정이다. 위성레이저반사경은 지상으로부터 방사된 레이저가 위성에 부착된 반사경으로부터 되반사되어 돌아오는 광자(Photon)의 이동시간을 측정함으로써 관측소와 위성까지의 거리를 정밀하게 측정하는데 사용된다. 현재 레이저반사경은 준비행모델을 개발하였으며, 환경시험을 수행하였다. 본 논문에서는 레이저반사경의 준비행모델의 개발과정을 소개하고, 환경시험 결과를 보고한다. 준비행모델 레이저반사경의 환경시험은 엔지니어링 모델에서 발생하였던 코너큐브프리즘의 파손없이 성공적으로 수행되었다.

• 한국정밀공학회지
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• 제24권9호
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• pp.148-157
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• 2007

A new method which uses distance fields scheme and marching cube algorithm is proposed in order to get an accurate offset model of arbitrary shapes composed of triangular net. In the method, the space bounding the triangular net is divided into smaller cells. For the efficient calculation of distance fields, valid cells which will generate a portion of offset model are selected previously by the suggested detection algorithm. These valid cells are divided again into much smaller voxels which assure required accuracy. At each voxel distance fields are created by calculating the minimum distances between corner points of voxels and triangular net. After generating the whole distance fields, the offset surface were constructed by using the conventional marching cube algorithm together with mesh smoothing scheme. The effectiveness and validity of this new offset method was demonstrated by performing numerical experiments for the various types of triangular net.

• 대한기계학회논문집
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• 제9권3호
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• pp.373-378
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• 1985

본 연구에서는 He-Ne레이저를 광원으로 하는 시준기 교정용 레이저 각도 간섭 계를 설계 제작하였으며 이 장치의 계통적 오차(systematic error)를 분석하였다. 또 간섭계의 반사경으로 사용된 두 코너큐브(corner cube) 중심 사이의 간격측정을 위 한 새로운 방법을 연구하였으며 이 측정의 정확도를 실험적으로 검사하였다.