• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.5
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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.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.3
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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.

• Korean Journal of Optics and Photonics
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• v.26 no.1
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• pp.17-22
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• 2015

The applications for retro-reflectors, with their unique reflection characteristics, have been expanding, to include venetian blind slats, displays, traffic safety mark, etc. We propose expandable structures of inclined corner cube retro-reflectors and analyze their corresponding reflection characteristics. Various traffic safety structures with retro-reflectors may be designed more quantitatively using the chart of characteristics we have presented.

• Proceedings of the KSME Conference
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• 2004.11a
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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.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.1
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• pp.92-99
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• 2008

KOMSAT-5 will attach an laser retroreflector array for precise orbit determination. Laser retroreflector array was developed by DFZ in Germany and have pyramid type composed of four corner cube prisms. In this paper, the performance analyses as effective area of retroreflector and photons measured by link budget and position of ground station were performed.

• Proceedings of the Optical Society of Korea Conference
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• 2007.02a
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• pp.231-232
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• 2007

• Journal of Electrical Engineering and Technology
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• v.5 no.2
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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.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.12
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• pp.1135-1142
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• 2007

STSAT-2 has an on-board satellite retroreflector array for precise orbit determination. Satellite retroreflector array reflects photon emitted from laser and uses to determine precisely the distance from ground station to satellite by the round-trip travel time of photon. The retroreflector array of protoflight model has been developed and verified through environmental tests. This paper describes the protoflight model of retroreflector array and reports environmental test results. The environmental tests of protoflight model retroreflector array were performed successfully without damage of corner cube prism occurred in engineering model development.

• Journal of the Korean Society for Precision Engineering
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• v.24 no.9
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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.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.3
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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.