• 전기학회논문지
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• 제64권2호
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• pp.310-314
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• 2015

To improve the optical performance of the backlight unit with light guide plate(LGP), we investigated the effects of LGP patterns on the brightness and viewing angles properties of the backlight unit. We designed several patterns of LGP and calculated their optical properties by the optical simulation. The results reveal that the highest brightness and wide viewing angle was achieved with the extended-closed-polygon diffusion pattern and upper triangle prism pattern of the LGP.

• 제어로봇시스템학회논문지
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• 제14권5호
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• pp.444-452
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• 2008

This paper presents an overall image processing approach of defect inspection of patterned TFT-LCD panels for the real manufacturing process. A prototype of AOI(Automatic Optical Inspection) system which is composed of air floating stage and multi line scan cameras is developed. Adjacent pattern comparison algorithm is enhanced and used for pattern elimination to extract defects in the patterned image of TFT-LCD panels. New region merging algorithm which is based on border expansion is proposed to identify defects from the pattern eliminated defect image. Experimental results show that a developed AOI system has acceptable performance and the proposed algorithm reduces environmental effects and processing time effectively for applying to the real manufacturing process.

• 한국광학회지
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• 제20권6호
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• pp.361-365
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• 2009

본 연구에서는 패턴 빔을 이용하여 표면이 거친 물체의 단차를 비접촉 방식으로 측정 하는 방법에 대하여 연구하였다. 본 연구에 사용된 방법은 장치가 매우 간단하고 스페클 노이지가 영상에 미치는 영향이 작아 재현성 면에서 매우 우수하였다. 특히 기준면에 문양이 없는 경우에는 기존의 자동 초점 측정 장치로는 측정하기 어려우나, 본 연구 방법에 의해 측정이 가능함을 보였다. 그리고 측정 시간이 매우 짧고 재현성이 좋으며 장치가 간단하여 산업 현장에서 응용하기 적절한 방법이다.

• 융복합기술연구소 논문집
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• 제2권1호
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• pp.43-48
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• 2012

Generally, in-plane position of moving object is measured referring to the reference pattern attached to the object. From optical camera to magnetic reluctance probe, there are many ways detecting a variation of the periodical pattern. In this paper, the various operating principles developed for in-plane positioning are reviewed and compared each other. And, a novel method measuring large rotation as well as x, y linear displacements is suggested, including a detailed description of the overall system layout. It is a modified version of the surface encoder, which is a robust digital measuring method. From the surface encoder, the rotation of an object is measured indirectly through a compensated input of optical servo and independently of linear displacements. So, the operating range can be extended simply by enlarging the reference pattern, without magnifying the decoding units.

• Journal of the Optical Society of Korea
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• 제17권1호
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• pp.50-56
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• 2013

Optical-fiber electronic speckle pattern interferometry (ESPI) is a non-contact, non-destructive examination technique with the advantages of rapid measurement, high accuracy, and full-field measurement. The optical-fiber ESPI system used in this study was compact and portable with the advantages of easy set-up and signal acquisition. By suitably configuring the optical-fiber ESPI system, producing an image signal in a charge-coupled device camera, and periodically modulating beam phases, we obtained phase information from the speckle pattern using a four-step phase shifting algorithm. Moreover, we compared the actual defect size with that of interference fringes which appeared on a screen after calculating the pixel value according to the distance between the object and the CCD camera. Conventional methods of measuring defects are time-consuming and resource-intensive because the estimated values are relative. However, our simple method could quantitatively estimate the defect length by carrying out numerical analysis for obtaining values on the X-axis in a line profile. The results showed reliable values for average error rates and a decrease in the error rate with increasing defect length or pressure.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 춘계학술대회 논문집
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• pp.533-534
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• 2012

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.539-540
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• 2013

• Journal of the Optical Society of Korea
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• 제14권4호
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• pp.357-362
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• 2010

The joint transform correlator (JTC) has been the best known technique for pattern recognition and identification. This paper proposes a new technique of fringe adjustment by adopting a sinusoidal amplitude-modulated iterative filter convolved with an interference fringe pattern in the joint power spectrum (JPS) domain. The comparison of our new technique and other techniques is presented to show that the newly proposed technique can successfully improve both the correlation peaks and the peak signal-to-noise ratio (PSNR). Simulated results of enhanced interference fringes are also presented.

• 한국광학회지
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• 제12권3호
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• pp.190-199
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• 2001

본 연구에서는 193nm의 ArF excimer laser 광원과 0.65의 NA를 갖는 광학계에서 기본 선폭이 $0.1{\mu}m$이고 duty ratio 가 1:1인 dense line & space(LS) 패턴에 대하여 여러사입사 조명 조건에 따른 초점심도(Depth of Focus; DOF)와 cutoff intensity를 확인하고 기본 capacitor 패턴에서 광학적 근접효과 보정을 위한 hammer head형 보조 패턴의 크기와 여러사입사 조건에 다른 DOF와 cutoff intensity의 변화에 대하여 알아보았다. 그결과 0.1$\mu$m급의 dense 패턴 구현을 위해서는 전형적인 X자형 사구 조명보다는 십자(+)형 사구 조명이나 환형조명이 보다 효과적인 것을 알수 있었다. 이와 더불어 보조 패턴의 크기가 약간 변한다 하더라도 일정한 초점심도와 cutoff intensity를 유지하는 경향을 보이는 특정한 조명 조건이 존재함을 밝히고 그에 따라 최적의 조명 조건과 보조 패턴의 크기에 대하여 알아보았다.

• 한국결정성장학회지
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• 제22권1호
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• pp.42-50
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• 2012

Mural Art는 빛의 색채 반응과 몰입, 확산 작용을 통하여 다양한 이미지를 나타내게 할 수 있는 디자인 작업이다. 본 논문은 천연 보석의 광학 현상을 Mural Art에 적합한 Digital Pattern으로 형성하고, 보석 및 광물의 광채와 작품 디자인과의 연관성에 대하여 고찰하였다. 작품 디자인의 상호(관련) 작용에 나타난 새로운 가능성을 광채가 아름다운 울트라 마린(Ultramarine)과 스펙트럼(Spectrum)의 색채 예술로서 벽면에 기초하여, 고해상도 Image의 그래픽 디자인으로 표현하고, 지속가능한(3D) Simulation의 Interior(Presentation) Modeling으로 활용하여 보았다.