• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.355-359
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• 2006

For the poor observability of azimuth misalignment angle and east gyro drift rate of the traditional initial alignment, a bran-new SINS stationary fast self-alignment approach is proposed. By means of analyzing the characteristic of the strapdown inertial navigation system (SINS) stationary alignment seriously, the new approach takes full advantage of the specific force and angular velocity information given by inertial measurement unit (IMU) instead of the mechanization of SINS. Firstly, coarse alignment algorithm is presented. Secondly, a new fine alignment model for SINS stationary self-alignment is derived, and the observability of the model is analysed. Then, a modified Sage-Husa adaptive Kalman filter is introduced to estimate the misalignment angles. Finally, some computer simulation results illustrate the efficiency of the new approach and its advantages, such as higher alignment accuracy, shorter alignment time, more self-contained and less calculation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.6
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• pp.1038-1044
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• 2016

In this paper, a SDINS(Strapdown Inertial Navigation System) rapid initial alignment technique robust to the pyro-shock in multi-launch rocket system is proposed. The proposed method consists of three steps. Firth, transfer alignment is performed to estimate misalignment between MINS(Master INS) and SINS(Slave INS), and the estimated misalignment is written in the memory when transfer alignment is completed. Next, the pre-filtering process is performed to get rid of the acceleration error induced by launcher vibration. Finally, the horizontal alignment is performed to compensate misalignment variation caused by pyro-shock. We verified the performance of the proposed alignment method comparing with the conventional transfer alignment method. The simulation shows that the proposed initial alignment technique improves alignment performance.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.1
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• pp.150-156
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• 1994

To meet the process requirement of semiconductor device manufacturing, it is necessary to improve the alignment accuracy in exposure equipments. We developed the excimer laser stepper and will describe the methodology for alignment measurement and experimental results. Our wafer alignment system consists of off-axis optics, TTL(Through The Lens) optics and high precision stage. Off-axis alignment utilizes the image processing and /or diffraction from thealign marks of off-centered chip area. On the other hand, TTL alignment can be used for the die-by-die alignment using dual beam interferometry. When only off-axis alignment was used, the experimental alignment error(lml+3 .sigma. ) was 0.26-0.29 .mu. m, and will be reduced down to 0.15 .mu. m by adding TTL alignment.

• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.2
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• pp.154-159
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• 2013

Alignment tolerance for EO/IR airborne camera using common optic is an important factor in stabilization accuracy and geo-pointing accuracy. Before airborne camera is mounted on the aircraft, defining alignment tolerance and verification of it is essential in production as well as research and development. In this paper we establish basic concept on the definition and elements of alignment tolerance for airborne camera and propose how to measure each of those elements. Components and the measurement sequence of alignment tolerance are as follows: 1) tolerance of alignment between EO and IR LOS. 2) tolerance of sensor alignment. 3) tolerance of position reporting accuracy. 4) tolerance of mount alignment

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.9
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• pp.677-681
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• 2013

Apart from the deposition of alignment layer, alignment process needs to be involved for alignment of liquid crystal (LC) molecules. To simplify manufacturing process, several method were used such as rubbing, ion-beam irradiation, UV irradiation, and lithography. But, eventually it needs another treatment for LC alignment. Here, we suggested Si induced polyimide (PI) alignment layer at low temperature. Using this method, we are able to eliminate the alignment process and found that the alignment and electro-optic performance are much better than that of the rubbed PI LC cells. Compared to the rubbed PI cells, the response time was decreased by 70% and C-V characteristics have hysteresis-free.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.5 s.182
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• pp.103-110
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• 2006

Automatic optical alignment modules are a key technology in optical communication system. However, the optic component assembly depends highly on manual or semi-automated alignment process. In this paper, a novel alignment mechanism with minimum degree-of-freedom has been designed and theoretical models are derived from geometric optical characteristics on collimators, optical filters and optical ray alignment. The automatic alignment control algorithm has been newly developed based on the mechanism and models, and then we make fast, precise and reliable alignment through the algorithm. The reliability of developed modules has been verified with various simulations and performance evaluations.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1393-1398
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• 2009

We once have announced that we developed a horizontal large-area alignment system with an alignment accuracy of < ${\pm}3{\mu}m$ and an alignment time of < 30 seconds, a core process module for RGB direct pattering by using a fine metal mask, which can process a Gen 4 ($730{\times}920mm^2$) substrate for high resolution OLED products. In this article, we presents a brand-new vertical alignment system for a even larger substrate of Gen 5 and beyond which can provide a better alignment accuracy and a higher throughput. The newly developed system exhibits an alignment accuracy of < ${\pm}2{\mu}m$ and an alignment time of < 20 seconds which, we believe, can open a new era for manufacturing large-size OLED monitors and TVs.

• Journal of the Semiconductor & Display Technology
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• v.9 no.3
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• pp.47-51
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• 2010

This paper presents a wafer pre-alignment system which is improved using the image of the entire wafer area. In the previous method, image acquisition for wafer takes about 80% of total pre-alignment time. The proposed system uses only one image of entire wafer area via a high-resolution CMOS camera, and so image acquisition accounts for nearly 1% of total process time. The larger FOV(field of view) to use the image of the entire wafer area worsen camera lens distortion. A camera calibration using high order polynomials is used for accurate lens distortion correction. And template matching is used to find a correct notch's position. The performance of the proposed system was demonstrated by experiments of wafer center alignment and notch alignment.

• Journal of Sensor Science and Technology
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• v.30 no.3
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• pp.125-130
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• 2021

In this study, the degree of alignment of polymer microfibers produced by electrospinning using a rotating water collector was evaluated. Aligned micro- and nano-fibers are required in various practical applications involving anisotropic properties. The degree of fiber alignment has many significant effects; hence, and accurate quantitative analysis of fiber alignment is necessary. Therefore, this study developed a simple and efficient method based on two-dimensional fast Fourier transform, followed by ellipse fitting. As a demonstrative example, the polymer microfibers were electrospun on the rotating water collector as the alignment of microfibers can be easily controlled. The analysis shows that the flow velocity of the liquid collector significantly affects the electrospun microfiber alignment, that is, the higher the flow velocity of the liquid collector, the greater is the degree of microfiber alignment. This method can be used for analyzing the fiber alignment in various fields such as smart sensors, fibers, composites, and textile engineering.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2007.04a
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• pp.471-474
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• 2007

On the road, geometric structure such as horizontal alignment, vortical alignment and crossing inclination ate important to explain characteristics of road and safety analysis. Especially, horizontal and vortical alignment are have to do with safety of covering. In existing road, for the safety analysis or alignment improvement and expansion pavement, it needs alignment factor of road. Alignment factor of road can be acquired by design drawing. But, design drawing can be not exist because of rack of facility management and national policy that centered to construction. And also, existing design drawing have a lot of differences in comparison with another existing design drawing cause of alignment improvement. In this case, for the precise analysis of alignment, 3-dimensional location information on the road centerline and acquisition of location information which related geometric structure are must to be preceded. In this study, therefore, it provide alignment factors which needed to alignment improvement and road safety analysis by acquisition of road space information and extraction of road centerline data using LiDAR data.