• 한국멀티미디어학회논문지
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• 제19권3호
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• pp.633-641
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• 2016

Automatic defect inspection system is composed of the step in the pre-processing, defect candidate detection, and classification. Polarizing films containing various defects should be minimized over-detection for classifying defect blobs. In this paper, we propose a defect detection algorithm using a skewness of histogram for minimizing over-detection. In order to detect up defects with similar to background pixel, we are used the characteristics of the local region. And the real defect pixels are distinguished from the noise using the probability density function. Experimental results demonstrated the minimized over-detection by utilizing the artificial images and real polarizing film images.

• 반도체디스플레이기술학회지
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• 제20권4호
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• pp.55-61
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• 2021

In this paper, we proposed and implemented defect detection methods of polarized film with half-wave phase retardation plates. We investigated the principles of phase retardation compensation and optical principle of half-wave phase retardation plates. We analyzed of samples of polarized film with half-wave phase retardation plates. The optical defect detection methods are proposed and the performance is validated with experiments.

• 한국정보통신학회논문지
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• 제17권8호
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• pp.1899-1907
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• 2013

본 논문에서는 초미세 패턴으로 구성된 칩-온-필름(Chip-on-Film, COF) 패키징 작업에서 발생하는 결함들을 참조영상에 기초하여 효율적으로 검출하고 분류하는 시스템을 제안한다. COF패키징 제작 과정에서 발생하는 치명적인 결함은 개방(open), 일부개방(mouse bite, near open), 단락(hard short) 및 돌기(protrusion, near short, soft short) 등을 포함한다. 이러한 결함을 검출하기 위해서는 기존에 직접 육안으로 식별하거나 또는 전기회로 설계를 이용하는 방법을 사용하였다. 그러나 이러한 방법은 매우 많은 시간과 고비용이 요구되는 단점이 있다. 본 논문에서는 참조영상을 사용하여 효과적으로 결함유무를 판단하고 결함이 발생되는 경우에 결함의 종류를 4 가지 형태로 분류하는 시스템을 제안한다. 제안방식은 검사영상의 전처리, 관심영역 추출, 지역이진분석에 의한 이물 특징 분석과 분류 등을 포함한다. 수많은 실험을 통해, 제안된 시스템은 초미세 패턴을 가진 COF의 결함 검사 및 분류에 대해 기존의 방식에 비해 시간과 경비를 줄이는데 효과적임을 보인다.

• 한국정보과학회논문지:소프트웨어및응용
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• 제34권5호
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• pp.447-454
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• 2007

최근 TFT-LCD (Thin film transistor liquid crystal display)패널의 수요증가에 비례하여 공정상 발생하는 LCD 불량의 수도 증가하고 있다. LCD 불량은 배경화면과 미세한 밝기대비 차이를 가지는 패널상의 불균등한 영역으로서 크게 정형과 비정형으로 나누어지며 사람의 눈에 매끄럽지 않게 보여진다. 이러한 불량은 배경과의 대비 차이가 미세하여 기존의 임계수준 검출이나 윤곽선 검출로는 불량을 검출할 수 없다. 본 논문은 비정형 LCD 불량을 독립성분분석, 적응 임계수준 검출 그리고 왜도를 이용하여 검출하는 방법을 제시한다. 본 검출방법은 잡음이 심한 영상에 대해서도 대응력이 뛰어나며, 생산라인에서 성공적으로 적용된다.

• 한국지능시스템학회논문지
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• 제19권6호
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• pp.743-748
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• 2009

본 논문은 2차원 연속 웨이블릿을 이용하여 조명에 의한 불균일한 휘도성분을 제거하여 TFT Display 핵심 부품인 편광필름 영상내의 결함을 검사 할 수 있는 방법을 제안한다. 영상 신호는 불균일한 휘도 분포와 노이즈 신호, 그리고 결함 신호로 구성되어 있다. 영상의 2차원 웨이블릿 변환은 스케일이 다른 여러 성분이 중첩된 다해상도 구조를 형성한다. 본 논문에서는 1차원 미분 가우시안 웨이블릿을 적용하여 영상에 중첩되어 있는 다해상도 성분 중 배경 휘도 성분을 효율적으로 추출하여 제거하는 전처리 기법을 제안한다. 이를 이용하여 원 영상에서 배경 성분을 분리할 수 있어 보다 신뢰성 있게 결함을 검출할 수 있다.

• 전기전자학회논문지
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• 제18권2호
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• pp.234-239
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• 2014

This paper proposes a new automatic detection method to inspect mura defects on display film surface using morphological image processing and labeling. This automatic detection method for mura defects on display films comprises 3 phases of preprocessing with morphological image processing, Gabor filtering, and labeling. Since distorted results could be obtained with the presence of non-uniform illumination, preprocessing step reduces illumination components using morphological image processing. In Gabor filtering, mura images are created with binary coded mura components using Gabor filters. Subsequently, labeling is a final phase of finding the mura defect area using the difference between large mura defects and values in the periphery. To evaluate the accuracy of the proposed detection method, detection rate was assessed by applying the method in 200 display film samples. As a result, the detection rate was high at about 95.5%. Moreover, the study was able to acquire reliable results using the Semu index for luminance mura in image quality inspection.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.333-336
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• 2006

High Pressure Annealing System was developed to improve the characteristics of low-temperature poly-silicon thin film transistors.. (TFTs). The high-pressure steam annealing was applied to the poly-silicon film made by rapid thermal annealing method. The carrier lifetime was investigated by Microwave detection of the Photo-Conductive Decay and the increase of carrier lifetime which indicates the reduction of the defect was observed by high-pressure steam annealing of 1MPa 600C 1hour.

• 반도체디스플레이기술학회지
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• 제11권2호
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• pp.45-51
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• 2012

Multilayer co-extrusion blown film construction is a popular technique for producing plastic films for various packaging industries. Automated detection of defective films can improve the quality of film production process. In this paper, we propose a film inspection system that can detect and classify film defects robustly. In our system, first, film images are acquired through a high speed line-scan camera under an appropriate lighting system. In order to detect and classify film defects, an inspection algorithm is developed. The algorithm divides the typical film defects into two groups: intensity-based and texture-based. Intensity-based defects are classified based on geometric features. Whereas, to classify texture-based defects, a texture analysis technique based on local binary pattern (LBP) is adopted. Experimental results revealed that our film inspection system is effective in detecting and classifying defects for the multilayer co-extrusion blown film construction line.

• 반도체디스플레이기술학회지
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• 제21권2호
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• pp.74-84
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• 2022

As the semiconductor industry develops, the difficulty of newly required process technology becomes difficult, and the importance of production yield and product reliability increases. As an effort to minimize yield loss in the manufacturing process, interests in the process defect process for facility diagnosis and defect identification are continuously increasing. This research observed the plasma condition changes in the multi oxide/nitride layer deposition (MOLD) process, which is one of the 3D-NAND manufacturing processes through optical emission spectroscopy (OES) and monitored the result of whether the change in plasma characteristics generated in repeated deposition of oxide film and nitride film could directly affect the film. Based on these results, it was confirmed that if a change over a certain period occurs, a change in the plasma characteristics was detected. The change may affect the quality of oxide film, such as the film thickness as well as the interfacial surface roughness when the oxide and nitride thin film deposited by plasma enhenced chemical vapor deposition (PECVD) method.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.123-127
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• 1997

Recently, it is gradually raised necessity that interface is measured accurately and managed in industrial circles and medical world, An Ultrasonic wave transmitted from a focused beam transducer is being expected as a powerful tool for NDE of micro-defect. The ultrasonic NDE of the defect is based on the form of the wave reflected form the interface In this study, regarding to the thickness of film which is in opaque object and thickness measurement was done by MEM-cepstrum analysis of received ultrasonic wave. In measument results, film thickness which is beyond distance resolution capacity was measured accurately. Also, automatically repeated discrimination analysis method can be decided in the category of all kinds of defects on semiconductor package.