• 한국산학기술학회논문지
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• 제11권4호
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• pp.1278-1284
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• 2010

이 논문에서는 TFT-LCD의 제조공정에서 발생하는 mura를 효율적으로 검출하는 multi-point FFT를 기반으로 한, 2차원 FFT를 이용하는 새로운 전기적인 검출 방식을 제안한다. TFT-LCD의 mura 패턴은 어느 일정한 영역을 갖고 있으므로 어느 한 라인에서 관찰하면 sin 파의 모양으로 관찰된다. Mura의 모양은 원, 가로 타원, 세로 타원으로 분류할 수 있으며 2-D FFT 변환을 통하여 일정한 문턱치와 비교하면 mura를 쉽게 검출할 수 있음을 보인다. 실험영상의 simulation을 통하여 제안 알고리즘이 다양한 크기의 mura 패턴을 효과적으로 검출할 수 있음을 보였다. 따라서 제안된 알고리즘은 TFT-LCD mura의 자동 검사 시스템에 이용될 수 있을 것이다.

• Industrial Engineering and Management Systems
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• 제8권3호
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• pp.148-154
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• 2009

In recent days, large-sized flat-panel display (FPD) has been increasingly applied to computer monitors and TVs. Mura defects, appearing as low contrast or non-uniform brightness region, sometimes occur in manufacturing of the Thin-Film Transistor Liquid-Crystal Displays (TFT-LCD). Implementation of automatic Mura inspection methods is necessary for TFT-LCD production. Various existing Mura detection methods based on regression diagnostics, surface fitting and data transformation have been presented with good performance. This paper proposes an efficient Mura detection method that is based on a regression diagnostics using studentized residuals for automatic Mura inspection of FPD. The input image is estimated by a linear model and then the studentized residuals are calculated for filtering Mura regions. After image dilation, the proposed threshold is determined for detecting the non-uniform brightness region in TFT-LCD by means of monitoring the every pixel in the image. The experimental results obtained from several test images are used to illustrate the effectiveness and efficiency of the proposed method for Mura detection.

• 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 2007년도 7th International Meeting on Information Display 제7권2호
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• pp.1597-1599
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• 2007

In TFT-LCD, mura is a defect which degrades the display quality. The resistance difference between gate lines is the main cause of H-Block mura. Two methods could eliminate this defect. A thinner gate layer or gate fan-out pattern decrease mura level. H-Block mura has been reduced after implementing the new schemes.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.991-994
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• 2009

This paper reports of camera detection of Mura. The type, location, size, orientation and amplitude are found. As the luminance variation in Mura is down to less than app. 0.3 %, measurement apparatus, techniques and algorithms are developed to measure low noise data and to extract the Mura from data with the residual noise in the same magnitude as the Mura.

• 한국산학기술학회논문지
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• 제10권3호
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• pp.529-534
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• 2009

이 논문에서는 TFT-LCD의 제조공정에서 생기는 결함(Mura)을 효율적으로 검출할 수 있는 새로운 전기적인 검출방식을 제안한다. TFT-LCD의 결함은 영역을 갖고 있으므로 어느 한 라인에서는 sin파의 모양으로 관찰된다. 따라서 FFT 변환을 통하여 문턱치와 비교하면 쉽게 결함이 검출될 수 있음을 보였다. 여러 가지 크기의 결함 패턴이 발생한 경우에도 Multi-point FFT 변환을 수행하면 크기가 일치하는 FFT 변환으로 효과적으로 검출됨을 보였다. 따라서 이 논문에서 제안된 알고리즘은 TFT-LCD의 자동 결함 검출 장치에 다양하게 이용될 수 있을 것이다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.1062-1065
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• 2004

We have analyzed the cause of black "mura" and measured it in prism light guide plate(LGP). Properties of components used in a backlight uint(BLU) have changed by simulation tool. We get major factor of black "mura" for improvement in prism LGP. For the improvement of black "mura", removal of brightness "mura" at input light part must precede preferentially because of reflection characteristic of the prism LGP. Removal of brightness "mura" is improved by hanging of input light part in LGP and dispersion treatment.

• Journal of Information Display
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• 제12권3호
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• pp.121-124
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• 2011

The mechanism for lattice-shaped mura defects was proposed by characterizing the electro-optic properties of liquid crystal (LC), which showed different transmission properties between the normal and mura defect areas. An increase in the mura defect rate was observed when the dotted LC in the one drop filling (ODF) was exposed for a longer time. The dotted LC droplet at the edge evaporated more rapidly than that in the center. This resulted in a higher concentration of polar singles at the edge of the dotted LC droplet, leading to a higher ${\Delta}n$ value and higher transmittance. This implies that the reductio of the exposure time of the dotted LC to air plays a critical role in decreasing the occurrence of lattice-shaped mura defects in ODF.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 디스플레이 광소자분야
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• pp.165-168
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• 2004

We have analyzed the cause of black "mura" and measured it in prism light-guide plate (LGP). Properties of components used in a back light. unit (BLU) have changed by Simulation Tool. We get major factor of black "mura" for improvement in prism LGP. For the improvement of black "mura", removal of brightness "mura" at input light part must precede preferentially because of reflection characteristics of the prism LGP. Removal of brightness "mura" is improved by changing of input light part in LGP and dispersion treatment.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.1465-1468
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• 2006

We developed a new ellipsometer for MURA detection. This ellipsometer can measure MURA along the slit line on the sample with high sensitivity, because this ellipsometer irradiates a slit beam onto the sample but can reject the reflected light from the back surface of the substrate. This ellipsometer is suitable for measuring MURA of the surface of sample with high sensitivity.