• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.239-242
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• 2006

LCD-BLU (Liquid Crystal Display - Back Light Unit) is one of kernel parts of LCD unit and it consists of several optical sheets(such as prism, diffuser and protector sheets), LGP (Light Guiding Plate), light source (CCFL or LED) and mold frame. The LGP of LCD-BLU is usually manufactured by forming numerous dots with $50{\sim}200$ um in diameter on it by etching process. But the surface of the etched dots of LGP is very rough due to the characteristics of the etching process during the mold fabrication, so that its light loss is high along with the dispersion of light into the surface. Accordingly, there is a limit in raising the luminance of LCD-BLU. In order to overcome the limit of current etched dot patterned LGP, optical pattern design with 50um micro-lens was applied in the present study. The micro-lens pattern fabricated by modified LiGA with thermal reflow process was applied to the optical design of LGP. The attention was paid to the effects of different aspect ratio (i.e. $0.2{\sim}0.5$) of optical pattern conditions to the brightness distribution of BLU with micro-lens patterned LGP. Finally, high aspect ratio micro-lens patterned LGP showed superior results to the one made by low aspect ratio in average luminance.

• Journal of Korea Society of Industrial Information Systems
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• v.11 no.2
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• pp.79-85
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• 2006

As the portable information appliance is developed, the demand of flat panel display equipments and parts are steeply increased. Most of all, the applications of LCD such as LCD TV, monitor, digital camera, CNS(car navigation system) and game machine become diversified. With the result that the number of BLU production enterprise is increased and the research on the design of backlight with the superior optical properties is persistently in progress. In this study we developed the pattern design tools for CCFL(cold cathode flourescent lamp) backlight to improve the conventional pattern design environment in which the pattern is designed manually from the experience and the trial and error. For the verification of our research, we designed the light reflection surface patterns for a real model of backlight and we measured the brightness uniformity using the BM-7. From the brightness uniformity measurement, the BLU designed using the presented tool showed the tolerable performance only in the first try of pattern design rather than the fifth try of pattern design in case of the conventional pattern design.

• Journal of the Korean Vacuum Society
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• v.17 no.6
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• pp.495-500
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• 2008

The amount of vapor mercury for the generation of glow discharge plasma has been calculated in a fine tube fluorescent lamp having a mixed gas of Ne+Ar including a mercury. When the ionization of atom is considered by the collision between neutral atoms (Ne, Ar, Hg) and electrons of energy $kT_e{\sim}1\;eV$, the density of vapor mercury atom has been obtained as $n(Hg){\sim}3.43{\times}10^{22}m^{-3}$ for the plasma density $n_o{\sim}10^{17}m^{-3}$. In the fluorescent lamps of out diameter 4 mm used for $32{\sim}42$-inch LCD-TVs having a mixture gas of Ne(95%)+Ar(5%) with the pressure of 50 Torr, the quantity of vapor mercury for the glow discharge has been caculated as 0.02{\sim}0.08\;mg$.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1339-1342
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• 2006

We focused on improving of the optical efficiency in the direct BLU. We could achieve the optical efficiency by reducing the thickness of BLU and processing the prism shapes on a reflection sheet. And we were able to reduce the Lamps.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1804-1807
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• 2001

By comparing and analyzing the feature, brightness, chromaticity and uniformity of domestic LGPs and Japanese products, early home-manufacturing and stabilization in home-manufacturing are possible. By comparing and analyzing the distribution of brightness as sheets are varied, we can design an ideal sheet composition.

• Proceedings of the Optical Society of Korea Conference
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• 2008.07a
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• pp.347-348
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• 2008

언급한 바와 같이 사이즈별로 시장의 규모, 특징, 개발의 방향이 약간씩 달리하고 있으나 분명한 것은 공정단순화 및 광효율향상 포함한 원가절감을 위하여 기능성 시트들을 개발을 위한 활동이 활발하게 진행하고 있다. 광원은 중형이상의 경우 CCFL, EEFL이 주류를 이루고 있으나 초대형화, 고색재현, Local Dimming을 위한 LED 광원을 채택한 LED-BLU 개발을 활발히 진행 중이다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.635-636
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• 2011

• Design & Manufacturing
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• v.2 no.5
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• pp.1-4
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• 2008

LCD-BLU (Liquid Crystal Display - Back Light Unit) is one of kernel parts of LCD unit and it consists of several optical sheets(such as prism, diffuser and protector sheets), LCP (Light Guide Plate), light source (CCFL or LED) and mold frame. The LGP of LCD-BLU is usually manufactured by forming numerous dots with $50-200{\mu}m$ in diameter on it by erosion method. But the surface of the erosion dots of LGP is very rough due to the characteristics of the erosion process during the mold fabrication, so that its light loss is high along with the dispersion of light into the surface. Accordingly, there is a limit in raising the luminance of LCD-BLU. Especially, the negative and positive micro-lens pattern fabricated by modified LiGA with thermal reflow process was applied to the optical design of LGP.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.216-219
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• 2005

In recent, LCD becomes one of the main display devices and expected to have quite good market share during the next couple of years. The demand for low cost and high performance, however, is becoming severe as the competition among other display devices like PDP, OLED increases. To satisfy this demand from market, we need to optimize the parts or modules of the LCD, reduce the number of the assemble and enhance the process for the high brightness and uniformity of the LCD. The LCD consists mainly of LCD panel and Backlight unit(BLU). BLU, which takes big portion of the cost for LCD, consists of light source, light guide panel and many kinds of functional film. Recently light guide panel or film for BLU has micro patterns on its surface and consequently to reduce the number of parts and enhace the brightness and its uniformity. In this study, some methodologies for the fabrication of the master/stamper and molding the light quide panel are introduced for 50um pitch of prizm patterned substrate. Mechanical machining process is adapted and optimized to fabricate micro patterned stamper using the micro cutting tool. Injection molding technology is also developed to obtain uniformly replicated micro patterned products.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.51-52
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• 2006

FFL의 내구성 및 신뢰성 확보를 위해 Lamp 상태에서 원하는 부위에 $-15^{\circ}C$를 유지하기 위한 Cold Spot을 부착하여 Lamp안의 Hg이 완전히 포집되도록 한다. 이후 이 Cold Spot을 제거하여 Hg peak과 Ne Peak의 Ratio의 변화를 관찰하며 Hg이 이동하는 것을 관잘 하여 Lamp 내에서 이동 속도와 Lamp 간에 이동 속도를 확인 할 수 있다. Lamp 내에서는 80분이 경과한 후에 Hg 이동이 Saturation되는 것을 확인 할 수 있고, Lamp 간에는 100시간이 경과후에 Saturation 되는 것을 확인 할 수 있었고, Ratio는 Channel내는 70 ~ 150, Channel간에는 6~10 정도임을 확인하여 Hg이 이동되는 속도와 회복되는 수준을 알 수 있었다.