• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05a
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• pp.123-127
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• 2004

Cold cathode fluorescent lamp (CCFL) has been used as a light source for direct type backlights for LCD monitors or TV. One inverter for one CCFL was necessary for maintaining the lamp current so that many inverters were used to drive as many CCFLs of direct type backlight for LCD TV. An inverter for driving 16 CCFLs was developed to reduce the backlight cost. The length and diameter of CCFL were 450mm and 4mm, respectively. Backlight including 16 CCFLs for 26" LCD TV was assembled by using one inverter. The uniformities of the assembled backlight operated by the conventional inverter and the newly developed inverter were 75% and 88%, respectively.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.04a
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• pp.928-931
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• 2014

사용자와의 인터페이스가 많은 모바일 기기에서 TFT LCD는 현재 가장 많이 사용되는 디스플레이로 백라이트(backlight)로 인한 전력 소모가 많아 배터리 수명이 짧아지는 것이 큰 문제이다. 전력 절감을 위해 사용되는 backlight dimming 기법은 명암비 조정에 따른 이미지 왜곡의 보완 기법과 함께 많은 연구가 진행되고 있다. 본 논문에서는 PWM 구동에 의한 LED backlight 제어가 가능한 TFT LCD 보드 구현을 소개하고 이 보드를 대상으로 framebuffer와 LED 제어용 리눅스 장치 드라이버를 사용한 객체 기반의 저전력 인간 시각 만족의 화질 보상 dimming 알고리즘의 구현 연구 내용을 기술한다.

• 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$.

• Journal of the Korean Vacuum Society
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• v.17 no.6
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• pp.481-486
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• 2008

The different degrees of blackening were observed at the inner surface of borosilicate, soda-lime, and aluminosilicate glass tubes having different sodium (Na) contents. The sodium contents ($Na_2O$) within the borosilicate, soda-lime, and aluminosilicate glass tubes were found to be 4%, 14%, and 0.06%, respectively. The degree of blackening was shown to increase as the sodium content within the glass of the fluorescent lamp containing Ne+Ar+Hg gas mixture. Higher degree of blackening was observed from the inner surface of the glass tube coated with $Y_2O_3$. The blackening was found to be originated from the amalgam of $NaHg_2$ generated by the chemical reaction between the mercury ions within the discharge gas and sodium within the glass tube during operation.

• Applied Chemistry for Engineering
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• v.19 no.6
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• pp.661-667
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• 2008

In this study, cholesteric liquid crystal (CLC) was synthesized and applied as a polarizing component on the optical film of back light units (BLU) for LCDs. After mixing CLC with nematic liquid crystal, this mixture was fulfilled in the module consisting of two films and then its amplifying efficiency and polarizing ability for a planarly emitted light were examined to apply as a BLU polarizer film for increasing the brightness of light. The properties of CLC compound were tested by UV/Visible spectroscopy and polarizing optical microscopy (POM). Flexible spacer was made by linear carboxylic acid group of cholesteric derivatives between cholesterol mesogen units for one-axis orientation in each layer. The CLC containing film could be used as a module to increase the ability of polarization and to enhance brightness of BLU and to widen wavelength range by stacking the films.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.1
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• pp.79-84
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• 2003

A light guide panel is an element of the LCD backlight module that is often used for the display of compact electronic devices. In this study, a laser marking system is proposed to fabricate light guide panel, which can replace other manufacturing methods such as silk printing, stamping, or v-cutting methods. The objective of this research is to evaluate the process parameters of the laser marking system. Light guide patterns were marked with a 50W $CO_2$ laser (CW) to understand the effects of average power and scanning speed on the geometry and quality of groove pattern. The width of the fabricated grooves increases with increasing laser power and decreasing scan speed. In order to analyze surface characteristics and optical properties (luminance, uniformity), SEM photography and BM7 (luminance measuring system) were used. As a result, the optimal conditions of the process parameters were determined.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.1
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• pp.79-84
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• 2004

A light-guide is one of several important components of backlight unit in TFT-LCD. The manufacturing technology and optical system design of the light guide is very sensitive to quality and cost of the TFT-LCD module. In the present study a new manufacturing method which is called as direct surface forming(DSF) has been tested under various conditions. DSF is very similar to the well-known hot embossing except for partial contact between mold and substrate. The final V-groove pattern shows different shapes depend on the temperature of mold surface, contact time of mold and depth of V-groove.

• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.204-205
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• 2006

기존의 3${\sim}$4mm 간격을 가진 냉음극 형광램프(CCFL)나 외부전극형광램프(EEFL)는 휘도의 균일성과 응답속도가 열등하기 때문에 42인치보다 큰 크기를 가지는 LCD TV에 적합하지 않다. 그래서 대면적 BLU(backlight unit)에 적합한 평면형광램프(FFL)에 대한 관심이 높아지고 있다. 본 논문에서는 FFL의 발광 효율을 향샹시키기 위하여, 가스 혼합비를 변화시키면서, 2차원 유체코드를 이용한 수치해석을 통하여 방전효율에 영향을 미치는 요소가 Hg임을 확인 하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2008.08a
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• pp.266-266
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• 2008

• Journal of the Institute of Convergence Signal Processing
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• v.7 no.4
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• pp.161-168
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• 2006

In this paper, we propose a method for the pattern inspection of LCD module using the color compensation and pattern matching. The pattern matching is generally used for the inspection method of LCD module at the industry. LCD module has many defections such as the brightness difference of the back light, the optic feature of liquid crystal, the difference of the light penetrated by driving LCD and the color difference by the lighting. The conventional method without the color compensation can not solve these defections and decreases the efficiency of inspecting LCD module. The method proposed to inspect defective badness through the pattern matching after it compensated color difference of the LCD occurred by the various causes. At first, it revises with setting by standard tone of color with the LCD pattern of the reference image. And It perform the preprocessing and pattern matching algorithm on the compensated image. In experiment, we confirmed that this algorithm is useful to detect some defections of LCD module. The proposed methods was easy to detect the faulty product.