• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.602-606
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• 2008

LCD is supplied light by BLU(Back Light Unit) and the light represents color by each color filter. Also LCD adjusts the amount of light by controlling liquid crystal between the glass of upper plate and one of lower. However, it is impossible to completely exclude light due to the structural and physical characteristic of liquid crystal. Therefore, on transfering light through optical sheet and liquid crystal, many problems are generated. They are related with energy efficiency and get effective for the contrast of LCD to have lower contrast ratio than other display devices. To solve the problems, many techniques have been studied and developed but don't exist keys to solution for them. Among methods, local dimming is one example to be applied to LCD. In this paper we propose image processing algorithm for local dimming of BLU of LED used as light source. The proposed algorithm extracts maximum luminance signal and lights using each extracted signal on segmented region of BLU. Also the proposed algorithm generates image signal in corresponding to luminance of the segmented region and supplies them with LCD panel to represent image with improving luminance ratio.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.1043-1044
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• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2007.06a
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• pp.229-230
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• 2007

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.15-15
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• 2009

In many applications for display with LED, the thermal behavior of LED is most important issue in view of thermal management. The optical requirements of the displays for various applications make the designer to drive the LED at or over their on-design condition to achieve performances requested by users. In practical cases of large-sized TV with LED back light unit (BLU), the problem of increasing LED temperature can affect the reliability of LED itself and the optical performances of BLU as an assembly of LED. In this paper, the thermal management design of LED back light unit(BLU) for large-sized TV was performed

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.148-149
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• 2006

TFT-LCD BLU has been remarkably developed for a recent few years as TFT-LCD market is increased. Recently new BLU technologies and components are developed as more aggressively than before since TFT-LCD panel requires higher quality and resolution. Especially Samsung Electronics and LG Philips LCD of Korea are major LCD panel makers and the major optical materials of LCD BLU and panel for Samsung Electronics have been supplied by Samsung Cheil Industries. In this presentation introduction to main components of LCD BLU will be investigated details. Also characteristics and applications of optical polymers such as PMMA, PET etc for LCD display will be included and finally recent trends in optical materials for LCD BLU will be shown briefly.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.6
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• pp.811-816
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• 2011

We develop a plastic object lens for blu-ray disc playing pick-up module as morethan 0.85 numerical aperture in this research. We design plastic object lens for blu-ray disc playing pick-up module's each factor's in balanced and made our designed lens by injection molding. Furthermore, by correction designing in mold-core, we optimization our lens efficiency as world grade; wave front aberration $0.028{\lambda}$. RMS, light axis differential 0.3967arcmin. We can manufacture localized blu-ray disc's pick-up lens's component and by this fact we obtain international competitiveness. The result of this research will be very helpful to develop a single objective lens for 3 different wavelength of laser diodes in playing and recording pick-up module.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1271-1276
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• 2008

This study has explained about LED for BLU which is widely used in the kinds of display devices or lighting. It was shown that the open due to delamination were the dominant LED for BLU failure mode and mechanisms from failure analysis of LED samples. Then, we have defined failure as yellowing and 100% reduction of light output intensity of LED for BLU and acceleration factors as temperature and current in Accelerated Life Test(ALT). Finally, we have estimated the Weibull distribution, life-stress relationship, and accelerating factor is used by ALTA Software.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1556-1557
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• 2007

LCD BLU에 광원의 수명을 측정하고, 고장모드를 분석하기 위해서는 광원을 구성하고 있는 각각의 성분 중에서 광원 자체를 구성하고 있는 R/G/B 광원에 대한 Burn-in test 및 고장모드를 분석하였다. LCD BLU에 있어서 R/G/B LED광원의 역할은 BLU 자체의 수명과 성능에 가장 큰 영향을 미친다. 서로 각각 사용조건하에서의 수명과 성능의 차이에 따라서 BLU 자체의 수명이 결정된다. 이를 평가가기 위해 LED device에 대한 가속수명테스트를 위한 Burn-in test를 실시하였으며, 발생한 고장모드를 분석하였다. 분석결과 누설전류 증가로 인한 불량이 주로 발생하였다. 누설전류 증가를 평가하기 위해 Photo emission microscope(PHEMOS-1000, MoDooTEK Inc.)을 이용하여 저전류에서의 LED chip의 누설전류에 의한 발광을 관찰함으로 인해, LED chip의 신뢰성 및 평가 기준이 됨을 알 수 있다.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1564-1565
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• 2007

In comparison with CCFL, LED can have more various colours. The research into BLU to raise colour reproducibility is actively proceeding by using RGB LED. On this study, Direct BLU was designed by white LED and RGB LED. According to the result of the experiment, the colour uniformity degree of BLU model using white LED is better than RGB LED BLU. On the other hand, the colour reproducibility of RGB LED BLU is better than white LED. The research showed that the uniformity of white LED is 81.7%and RGB LED is 70.01%.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.503-505
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• 2009

In this paper, we research the method for write quality improvement by temperature characteristic of Laser diode for optical recording. Differential Resistance of Blu-ray laser diode is changed by temperature. We analyze the effect of the change of the differential resistance and propose the method for the write quality improvement.