• Journal of the Korean Society for Precision Engineering
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• v.23 no.1 s.178
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• pp.89-96
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• 2006

In this study, fabrication of the large area silicon mirror is accomplished by anisotropic wet etching using micromachining technology for implementation of integrated slim optical pickup and the process condition is also established for improving the mirror surface roughness. Until now, few results have been reported about the production of highly stepped $9.74^{\circ}$ off-axis-cut silicon wafers using wet etching. In addition rough surface of the mirror is achieved in case of tong etching time. Hence a novel method called magnetorheolocal finishing is applied to enhance the surface quality of the mirror plane. Finally, areal peak to valley surface roughness of mirror plane is reduced about 100nm in large area of $mm^2$ and it is applicable to optical pickup using infrared wavelength.

• Proceedings of the KIEE Conference
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• 2002.07c
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• pp.1985-1987
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• 2002

Silicon bulk micromachined micromirrors are designed and fabricated for out-of-plane right angle reflection. The micromirror is comprised of a minor plate, springs, magnetic bars and electrodes. Single crystalline silicon is used for a flatness improvement of a mirror plate. Out-of-plane right angle reflection requires a 45 degree operation of the micromirror. The micromirrors are operated by applying a magnetic field, which is generated by a coil located below a substrate. For an individual mirror operation, each mirror is clamped using an electrostatic force against the electromagnetic force. Angular deflections are measured and compared with theoretical data. The micro mirror operates up to 45 degree when magnetic field is 4 kA/m which is generated by a 115 mA coil current Simple addressing is tested, and it is shown that a clamping voltage is less than 5V.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.4 no.1
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• pp.25-36
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• 1986

Minimum three pairs of model are necessary to determine absolute coordinates of three-dimensional objects. This paper researches the method of analyzing three-dimensional coordinates of all sides of objects by photographing a pair of stereo model through the medium of mirror. An objective lies in improving the accuracy and the efficiency of mirror images method by introducing an error correction function for distortion of the mirror. Projected-onto-mirror points are transformed on the object plane through mirror plane equation. As the result, X-coordinates error is the largest and Y, Z-coordinates error represents about 1mm. Also, accuracy can be improved by introducing correction function for left and right mirror and correcting the distortion of mirror.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1522-1526
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• 2005

In this study, the fabrication of large area silicon mirror is accomplished by anisotropic etching using MEMS for implementation of integrated optical pickup and the process condition is also established for improving the mirror surface roughness. Until now, few results have been reported about the production of highly stepped $9.74^{\circ}$ off-axis-cut silicon wafer using wet etching. In addition rough surface of the mirror is achieved in case of long etching time. Hence a novel method called magnetorheolocal finishing is introduced to enhancing the surface quality of the mirror plane. Finally, areal peak to valley surface roughness of mirror plane is reduced about 100nm in large area of $mm^2$ and it is applicable to optical pickup using infrared wavelength.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1597-1600
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• 1997

Most autonomous mobile robots view things only in front of them. As a result they may collide against objects moving from the side or behind. To overcome the problem we have built an Active Omni-directional Range Sensor that can obtain omni-directional depth data by a laser conic plane and a conic mirror. Also we proposed a self-localization algorithm of mobile robot in unknown environment by fusion of Odometer and Active Omn-directional Range Sensor.

• Journal of Sensor Science and Technology
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• v.19 no.2
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• pp.130-136
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• 2010

The microbolometer array sensor with fine pitch pixel array has been implemented to the released amorphous silicon layer supported by two contact pads. For the design of focal plane mirror with geometrical flatness, the simple beam test structures were fabricated and characterized. As the beam length decreased, the effect of beam width on the bending was minimized, Mirror deformation of focal plane in a real pixel showed downward curvature by residual stress of a-Si and Ti layer. The mirror tilting was caused by the mis-align effect of contact pad and confirmed by FEA simulation results. The properties of bolometer have been measured as such that the NETD 145 mK, the TCR -2 %/K, and thermal time constant 1.99 ms.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.319-320
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• 2006

In this paper, we propose a vision based system employing two cameras to provide effective touch screen function. The two main processes - determining touch (or no-touch) and contact location of screen plane - are essential for enabling touch screen function. First region of interest is found by using color characteristic and histogram for determining the contact mode. Second, if the hand touches the mirror, the fingertip point in image is found using the correlation coefficient based on the mirror attribute. Subsequently, the fingertip coordinate in image is transformed to the location in mirror plane by using four predefined points (termed as four-point method) and bilinear transform. Representative experimental results show that the proposed system is suited to touch screen.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.5
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• pp.406-410
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• 2005

A depth measurement system that consists of a single camera, a laser light source and a rotating mirror is investigated. The camera and the light source are fixed, facing the rotating mirror. The laser light is reflected by the mirror and projected to the scene objects whose locations are to be determined. The camera detects the laser light location on object surfaces through the same mirror. The scan over the area to be measured is done by mirror rotation. Advantages are 1) the image of the light stripe remains sharp while that of the background becomes blurred because of the mirror rotation and 2) the only rotating part of this system is the mirror but the mirror angle is not involved in depth computation. This minimizes the imprecision caused by a possible inaccurate angle measurement. The detail arrangement and experimental results are reported.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.4
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• pp.437-445
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• 1999

Most autonomous mobile robots view only things in front of then, and as a result, they may collide with objects moving from the side or behind. To overcome this problem, an active omni-directional range sensor system has been built that can obtain an omni-directional depth map through the use of a laser conic plane and a conic mirror. In the navigation of the mobile robot, the proposed sensor system produces a laser conic plane by rotating the laser point source at high speed: this creates a two-dimensional depth map, in real time, once an image is captured. The results obtained from experiment show that the proposed sensor system is very efficient, and can be utilized for navigation of mobile robot in an unknown environment.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.12
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• pp.169-179
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• 1998

Plane mirror type laser interferometers are popularly being used in many modern ultraprecision machines, as they can perform simultaneous measurements of multiple axis positions with nanometer resolution capabilities. One important issue in this application of laser interferometers is to provide a good level of alignment between the reflecting mirrors and the laser beams so that measurement errors due to undesirable coupling effects can be avoided in multiple axis measurements In this investigation, a thorough metrological analysis is given to develop an suitable mathematical model for a precision x-y stage in which the orthogonality misalignment between the reflecting mirrors significantly affects overall x-y mea-surement results. Then a noble calibration method is suggested in which two-dimensional displacement sensors of moire gratings of concentric circles are used to realize the reversal principle of orthogonality evaluation in situ. Finally, actual experimental results are discussed to verify that the suggested method can effectively calibrate the orthogonality error with an uncertainty of 0.2667 arcsec.