• Journal of Sensor Science and Technology
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• v.21 no.6
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• pp.440-445
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• 2012

Contact-type Linear Encoder-like Capacitive Displacement Sensor (CLECDiS) is a novel displacement sensor which has wide measurable range with high resolution. The sensor, however, is very sensitive to relative rotational alignment between stator and mover of the sensor as well as its displacement. In addition to, there can be some disturbances in the relative rotational alignment, so some noises occur in the sensor's output signal by the disturbances. This negative effect of the high sensitivity may become larger as increasing sensitivity. Therefore, this negative effect of the high sensitivity has to be compensated and reduced to achieve nanometer resolution of the sensor. In this study, a new type capacitive linear encoder with a mechanical guide is presented to reduce the relative rotational alignment problem. The presented method is not only to reduce the alignment problem, but also to assemble the sensor to the stage conveniently. The method is based on a new type CLECDiS that has mechanical guide autonomously. In the presented sensor, when the device is fabricated by micro-machining, the guide-rail is also fabricated on the surface of the sensor. By the direct fabrication of the guide-rail with high precision micro-machining, errors of the guide-rail can be reduced significantly. In addition, a manual yaw alignment is not required to obtain large magnitude of the output signal after the assembly of the sensor and the stage. The sensor movement is going to follow the guide-rail automatically. The prototype sensor was fabricated using the presented method, and we verify the feasibility experimentally.

• Korean Journal of Optics and Photonics
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• v.15 no.4
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• pp.391-396
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• 2004

Spaceborne earth observation or astronomical payloads often use Cassegrain-type telescopes due to the limits in mass and volume. Precision optical alignment of such a telescope is vital to the success of the mission. This paper describes the simulated optical alignment methods using interferograms, wavefront error, and reverse-optimization method for different levels of alignment accuracy. It concludes with the alignment experiment results of a Cassegrain type spaceborne camera with 300mm entrance pupil diameter.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.9
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• pp.111-118
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• 2004

The automatic assembly system of micro optical filter is a key technology in the development of optical modules with high functionality. In order to develop an automatic assembly system of optical fiber and filter, we have firstly developed the system and program capable of characterization of 30${\mu}m$-thick film filters as well as conventional optical filters. Moreover, we have carried out the characterization of optical filter using the developed system and program, and compared experimental results with by conventional handwork. The measurement of optical filters using the present system is faster, more precise and more reliable than those based on the conventional handwork.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.9
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• pp.879-884
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• 2015

Printed electronics is a technology that produces electronic devices and circuits by printing functional ink on a web, which is a film-like flexible material. This technology is suitable for large-scale and high-speed mass production, and is a next-generation process technology that can fabricate electronic devices from flexible materials. As precise measurement of the positions of the web is required in order to commercialize such a printed electronics process, a measurement system with an optical encoder with a precision of micrometers had been proposed in the preceding research of this study. However, the lateral positions of the web could not be measured in the preceding research as the phenomenon of the entire web being moved in the lateral direction could not be detected. In this study, a measurement system that utilizes the differences in the amount of light reflected from the alignment patterns depending on the web positions in the lateral direction was proposed for measuring the lateral positions of the web. In addition, its reliability was verified and then the effect when measuring printed alignment patterns was analyzed by experiments.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.4
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• pp.194-201
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• 2004

Optical fibers are indispensable fer optical communication systems that transmit large volumes of data at high speed. But the aligning technology under the sub-micron accuracy is required for the precise axis adjustment and connection. For the purpose of precise alignment of the optical arrays, in this research, we have developed the 12-axis(with 8 automated axis and 4 manual axis) automatic optical fiber alignment system including the image processing-based searching system, the automatic loading system using the robot and the suction toot and the automatic UV bonding system. In order to obtain the sub-micron alignment accuracy, two 4-axis PC-based motion controllers and the two 50nm resolution 6-aixs micro-stage actuated by micro stepping motors are adopted. The fiber aligning procedure consists of two steps. Firstly, the optical wave guide and an input optical array are aligned by the 6-axis input micro-stage with the IR camera. The image processing technique is introduced to reduce primary manual aligning time and result in achieving the 50% decrease of aligning time. Secondly, the IR camera is replaced by the output micro-stage and a wave guide and two optical arrays are aligned simultaneously before the laser power intensity delivered to the optical powermeter reached the threshold value. When the aligning procedure is finished, the wave guide and arrays are W bonded. The automatic loading/unloading system is also introduced and the entire wave guide handing time is reduced significantly compared to the former commercial aligning system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.843-847
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• 2007

The unbalanced mass of a high precision rotor deteriorates mechanical performance of the rotor. The geometrical center of a rotor generally corresponds to the rotational axis of the rotor. However, this alignment carried out with a stationary rotor does not guarantee the dynamic rotor balance. There have been a number of schemes for the correction of the imbalance published for decades especially in the hard drive industry where the issues are directly affecting manufacturing costs and product performances. Realizing the significance of the problem, the present work tries to refine one of the methods that works by applying external impact during a rotor spins. A systematic way to apply the external impact to a rotating rotor has been introduced to minimize imbalance correction process time.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.8
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• pp.720-725
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• 2007

The unbalanced mass of a high precision rotor deteriorates mechanical performance of the rotor. The geometrical center of a rotor generally corresponds to the rotational axis of the rotor. However, this alignment carried out with a stationary rotor does not guarantee the dynamic rotor balance. There have been a number of schemes for the correction of the unbalance published for decades especially in the hard drive industry where the issues are directly affecting manufacturing costs and product performances. Realizing the significance of the problem, the present work tries to refine one of the methods that works by applying external impact during a rotor spins. A systematic way to apply the external impact to a rotating rotor has been introduced to minimize unbalance correction process time.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.7
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• pp.56-62
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• 2019

The high-precision laser scriber carries out scribing alumina ceramic substrates for manufacturing ultra-small chip resistors. The ceramic substrates are loaded, aligned, scribed, transferred, and unloaded. The entire process is fully automated, thereby minimizing the scribing cycle time of the ceramic substrates and improving the throughput. The scriber consists of the laser optical system, pick-up module of ceramic substrates, pre-alignment module, TH axis drive work table, automation module for substrate loading / unloading, and high-speed scribing control S/W. The loader / unloader unit, which has the greatest influence on the scribing cycle time of the substrates, carries the substrates to the work table that carries out the cutting line work by driving the X and Y axes as well as by adsorbing the ceramic substrates. The loader / unloader unit consists of the magazine up / down part, X-axis drive part for conveying the substrates to the left and right direction, and the vision part for detecting the edge of the substrate for the primary pre-alignment of the substrates. In this paper, the laser scribing machining simulation is performed by applying the instrument mechanism of each component module. Through this study, the scribing machining process is first verified by analyzing the process operation and work area of each module in advance. In addition, the scribing machining process is optimized by comparing and analyzing the scribing cycle time of one ceramic substrate according to the alignment stage module speed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.6
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• pp.57-63
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• 2005

According to increasing of demand for high accurate and quick measuring technology, they became to interest in industrial photogrammetry that can satisfy with this needs. This study is examined O-2A aircraft to check the application of Industrial Photogrammetry technology. To measure the aircraft alignment, the check points marked on it were used without exact aircraft design data. And to check any deformation of its external original feature, Pro-spot system has been used.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.153-154
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• 2006

Development of sorting machine for photo diode and its control system is addressed. The sorting machine for optical communication device requires high positional precision because the alignment is one of the most important point in the sorting process. This sorting method describes how to detect the target chip's angle and position from the wafer. The machine vision system is used for the feedback control. This sorting machine is implemented by motion controller, machine vision and various solenoid valve and is interfaced with RS-232c, GPIB and PCI communication. This system gets the position accuracy within $1{\mu}m$ with our experiments.