• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.3
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• pp.227-231
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• 2013

Electrodeionization is a hybrid separation process of electrodialysis and ion exchange to produce high purity water under electric field. This article provides a fabrication result of hole patterned metal electrode for elecrodeionization system. The hole patterns have been fabricated by nanosphere lithography (NSL). The technique utilizes the self-assembled nanospheres as lens-mask patterns and collimated laser beam source. The hole patterns have a periodic array structure. The images of hole pattern on metal electrode prepared were observed by SEM. We believe that the periodic hole patterned metal electrode structure is a useful device applicable for metal mat electrode in electrodeionization system.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.106-110
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• 2002

4S-Van is being developed in order to provide the spatial data rapidly and accurately. 4S-Van technique is a system for spatial data construction that is heart of 4S technique. Architecture of 4S-Van system consists of hardware integration part and post-processing part. Hardware part has GPS, INS, color CCD, camera, B/W CCD camera, infrared rays camera, and laser. Software part has GPS/INS integration algorithm, coordinate conversion, lens correction, camera orientation correction, and three dimension position production. In this paper, we suggest that adequate 4S-Van design is needed according to application environment from various test results.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.53.2-53
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• 2001

The Non-Contact Optical Sensor using the Hologram Laser for CD Pickup was developed to measure a shape of transparent objects and shown a good performance. Therefore the problems caused by the contact sensor are solved by using the Non-Contact Sensor. The Non-Contact Sensor has to move toward the objects and obtain the Focus Error Signal to measure a position of transparent objects. However, if the distance between the sensor and the object is shorter than the working distance of the objective lens, the sensor will be collided against the objects. In this paper we proposed a new algorithm to estimate the start position of the Focus Error Signal to solve the problems of collision between the sensor and the objects. In addition, we verified that the algorithm is free from the collision in the real time measurement.

• Electronics and Telecommunications Trends
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• v.36 no.5
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• pp.1-8
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• 2021

Over the last three decades, the development of Ti:sapphire femtosecond lasers has led to advancements in scientific and industrial fields. In particular, these advanced lasers show great potential for applications with bio-imaging and medical surgery, such as two-photon microscopy, nonlinear Raman microscopy, optical coherence tomography, and ophthalmic surgery. Herein, we present a detailed description of the theoretical and experimental physics of Kerr-lens mode-locked femtosecond Ti:sapphire lasers and its two-photon microscopy.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.47 no.1
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• pp.91-96
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• 2010

In this paper, a deformation measurement technology of the nuclear fuel rod is proposed. The deformation measurement system include high definition CCD or CMOS image sensor, lens, semiconductor laser line beam marker, and optical & mechanical accessories. The basic idea of the deformation measurement is to illuminate the outer surface of the fuel rod with collimated laser line beam at an angle of 45 degrees or higher. The relative motion of the fuel rod in the horizontal direction causes the illuminated laser line beam to move vertically along the surface of the fuel rod. The resulting change of laser line beam position in the surface of the fuel rod is imaged as the parabolic beam in the high definition CCD or CMOS image sensor. From the parabolic beam pattern, the ellipse model is extracted. And the slope of the long and the short axis of the ellipse model is found. The crossing point between the saddle point of the parabolic beam and the long & short axis of the ellipse model is taken as the feature of the deformed fuel rod. The vertical offset between feature points before and after fuel rod deformation is calculated. From the experimental results, $50\;{\mu}m$ inspection resolution is acquired using the proposed method, which is three times enhanced than the conventional criterion ($150\;{\mu}m$) of the guide for the inspection of the nuclear fuel rod.

• Journal of Digital Convergence
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• v.12 no.8
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• pp.295-302
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• 2014

Essential to the establishment of such 3D spatial information are the laser scanning technology to obtain high-precision 3D point group data and the photography-metric camera to obtain high-resolution multispectral image information. The photography-metric camera, however, lacks in usability for its broad scope of utilization due to the high purchase price, difficult purchase channel, and low applicability. This study thus set out to investigate a technique to establish multi-dimensional ortho-image data with a single lens reflex digital camera of high speed and easy accessibility for general users. That is, the study remodeled a single lens reflex digital camera and calibrated the remodeled camera to establish 3D multispectral image information, which is the essential data of 3D spatial information. Multi-dimensional ortho-image data were collected by surveying the reference points for stereo photos, taking multispectral shots of the objects, and converting them into ortho-images.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.49 no.7
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• pp.10-16
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• 2012

In this paper, we tried to realize a next generation MILES detection system which is robust to optical noise using a narrow band interference optical filter. Applying a narrow band interference optical filter which has the wavelength range of 895~915nm to the LASER wavelength of 900nm, we could obtain detection characteristics robust to strong optical noise which can be occurred in street battles. However, the MILES detection system has the blind range of detection in the incident angle range of $30^{\circ}{\sim}90^{\circ}$. To solve this problem we proposed a method of incident angle scatter using refractors. Applying a concave meniscus lens refractor which has diopter of 5.4 to the MILES detection system, we could eliminate the blind angle of detection.

• Korean Journal of Optics and Photonics
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• v.20 no.5
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• pp.294-300
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• 2009

To improve the output power of a photomixer as a THz source, we propose a four-leaf clover-shaped antenna structure which is composed of a highly resonant radiation element and a stable DC feed element. The resonance characteristics of the proposed structure were investigated on a half-infinite substrate first as a simplified radiation environment in order to save the computation time. Based on the antenna characteristics on a half-infinite substrate, the antenna structure was designed to have a maximum total efficiency and a maximum directivity on an extended hemispherical lens. In comparison with a full-wavelength dipole, an input resistance of this structure increased six fold and this characteristic significantly improved the mismatch efficiency between a photomixer and an antenna. THz output power from this structure is expected to increase by 2.7 times as compared to a full-wavelength dipole case.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.5
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• pp.131-138
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• 2023

In this paper, a free space optical communication device that can be used in a mobile base station of several km or less was fabricated and its characteristics were investigated. To overcome the loss due to atmospheric transmission, an optical fiber amplifier (EDFA) with an output of 23 dBm or more was used. In order to increase the focusing speed and miniaturization of the laser beam, an optical lens was manufactured, and a transmission lens was designed to have beam divergence within the range of 1.5 to 1.8 [mrad]. A PT module that controls PAN/TILT was fabricated in order to reduce pointing errors and effective automatic alignment between transceiver devices. In this study, Reed-Solomon (RS) code was used to maintain the transmission quality above a certain level. It was manufactured to be able to communicate at a wireless distance of 300m in a weather situation with visibility of 300m. For performance measurement, it was measured using BERT and eye pattern analyzer, and it was confirmed that BER can be maintained at 2.5Gbps.

• Korean Journal of Optics and Photonics
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• v.5 no.1
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• pp.166-172
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• 1994

The fiber optic receiver, ETRI APD-FET 1.0, is developed for the application of optical communication. This fiber optic receiver includes PD sub-module and pre-amplifier case. A single lens system is introduced for the PD sub-module. The sub-module consists of the avalenche photodiode(APD), GRIN rod lens, and a single mode fiber. The above components are enclosed into the stainless steel 304L housings. By bevelling the fiber end, the single mode fiber provides less than ~ 28 dB of optical return loss. The area of image focus is controlled by adjusting the length of spacer located in-between the fiber and the GRIN rod lens. The laser welding technique is applied to achieve the maximum coupling efficiency for the joining of each housing. In the pre-amplifier case, GaAs FET pre-amplifier workes for photocurrent amplification and the thermister is mounted to control the APD bias. The performance of ETRI APD-FET1.0 shows the sensitivity of - 30.3 dBm at $10^{-10}$ BER(bit error rate) and 2.5 Gbps optical random signal of $2^{23}-1$ word length. The fiber optic receiver is one of the essensial parts of the transmission module for B-ISDN. Also, the above optical packaging technology will be adapted for the developement of 10 Gbps transmission application 2.5 Gbps 5 Gbps