• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 춘계학술대회 논문집
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• pp.55-59
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• 2007

Technologies of super-precision micro pattern mold machining and high-performance optical films manufacturing using thereof forms the basis of recent display industries which have developed remarkably. Especially, it is the light guide plates and high luminous intensity prism sheets at BLU or FLU in LCD and lenses at virtual keyboard's display to be manufactured by micro machining technology. One way the industry requires to do that is by developing high-performance light guide plates or films which are existing light guide plates, diffusion films and luminance enhancement prism films all in one. In this research effort, basic processing of the micro pyramid structure by shaping method is proposed. Experiments of mold machining of pitch $20{\mu}m$ tetrahedral pyramid and pitch $100{\mu}m$ trihedral pyramid using a $90^{\circ}$ diamond tool were conducted to identify a variety of machining features, such as cutting forces, conditions of the surface, shapes of chips, and influence of materials.

• 한국표면공학회지
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• 제42권5호
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• pp.208-215
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• 2009

We employed atmospheric plasma to reactively remove the lubricant sprayed onto such industrial electronic parts as LCD chassis during sheet-metal forming processes and investigated basically the effect of plasma parameters on cleansing the surfaces of zinc-electroplated steel plates (EGI). Specimen prepared with some controlled amount of lubricant sprayed on their surfaces beforehand were subjected to two different kinds of atmospheric plasma, one being generated by using air and the other generated by using nitrogen (99.9% purity). Locating the plasma beams at the height range between 3.5 and 13.5 mm from the surface of each specimen and radiating for 5 to 30 seconds resulted out that the cases with a position of 3.5 mm and a duration of 5 seconds or longer showed the surfaces completely cleansed without a trace of lubricant. Furthermore we found out that the plasma generated by using simple air depicted higher cleansing ability than the other one generated by using expensive nitrogen, interestingly useful very much for industrial purposes. On another aspect, we confirmed that the drilled or cut surfaces of Zn-plated steel substrate would not be oxidized even under the influence of plasma during its cleansing process. Therefore, we could probably conclude from this fore-survey that a dry process adopting atmospheric plasma for cleansing industrial parts might be determined to become successful in terms of commercialization, cautiously.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.728-731
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• 2005

A light guide panel (LGP) is an element of the LCD back light unit, which is used for display devices. In this study, a laser marking process is applied to the fabrication of light guide panels as the new fabrication process. In order to obtain a light guide panel which has high luminance and uniformity, four principal parameters such as power, scanning speed, ratio of line gap, and number of line were selected as important factors. A Web-based design tool was developed to generate patterns of light guide panel, and the tool may assist the designer to develop optimized patterns. Topcon-BM7 was used for luminance measurement of each specimen 100mm$\times$100mm area. By Taguchi method optimized levels of each parameters such as 40W of power, 30mm/s of scanning speed, 100:50 ratio of pattern gap, and 90 line of pattern were found by Taguchi method.

• 한국기계가공학회지
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• 제9권6호
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• pp.1-6
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• 2010

Patterned optical components are widely used for optical products such as LCD and lighting. Since CCFL was used as a light source in the products, prism films having linear continuous optical patterns were widely used. However, LED which is a dot light source is popular recently, therefore, the optical products need new optical components having non-continuous optical patterns. Indentation machining method is a powerful method for machining of non-continuous pattern. When a copper mold and a brass mold were machined by this method, severe plastic deformation called pile-up was observed around the patterns. Since pile-up has negative relationship to ductility, this deformation can be eliminated by annealing treatment which makes the materials ductile. No plastic deformation occurred when machined after annealing at $600{^{\circ}C}$ and $575{^{\circ}C}$ for copper and brass, respectively. Finally, non-continuous optical patterns with high quality were machined on a copper mold and a brass mold successively.

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2006년도 추계학술대회 발표 논문집
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• pp.132-137
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• 2006

With the help of the development of digital-multimedia in the middle of 1990's, FDP(Flat Panel Display) had attracted considerable attention. Collimation proximity exposure system that transfers the pattern on wafer or glass exactly using mask and light with appropriate wavelength is core process in semiconductor and liquid display element. The performances of resolution required in precision exposure system are evaluated by resolving power, depth of focus and storage area. Most of development has targeted on these three factors. The optical design including lamp house has played an important role on the performance of exposure process. In this study, we evaluate the cooling system, concerning on exposure device with mercury lamp among the kernel equipment for the production of LCD, to prevent the instability of lighting due to long term accumulation of excessive heating inside the lamp house. Numerical analysis is conducted on full-scale model. The characteristics of three-dimensional flow, pressure and temperature distribution on exposure system are graphically depicted to estimate the whole cooling system for lamp house and to establish the design criteria.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.463-464
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• 2008

As the demands of LCD and PDP TV are increasing, the high performance HVICs(High Voltage Gate Driver ICs) technology is becoming more necessary. In this paper, we designed the HVIC that has enhanced noise immunity and high driving capability. It can operate at 500KHz switching frequency and permit 600V input voltage. High-side level shifter is designed with noise protection circuit and schmitt trigger. Therefore it has very high dv/dt immunity, the maximum being 50V/ns. The HVIC was designed using $1{\mu}m$ BCD 650V process and verified by Spectre and PSpice of Cadence inc. simulation.

• 한국기계가공학회지
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• 제4권4호
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• pp.28-33
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• 2005

Recently, trends of TFT-LCD toward larger scale and thinner thickness continue. so, demands of Light Guide Panel (LGP) which is to substitute for prism sheet are appeared. Functions of LGP obtaining polarization of light of the prism sheet as well as the incidence and reflection of light are demanded. This prism type LGP to complete functions of the existing LGP and polarization at once must be supported by micro machining technology of LGP surface. In this research, the machining characteristics of the various materials were analysed by shaping using V-shaped single crystal diamond tool. The characteristics are machined surface, machining force due to the variation of cutting depth. Used specimens are engineering materials, which are 6:4 brass, oxygen-free copper, Al6061, PC, PMMA. The FFT analysis of the measured cutting force was conducted. The cutting characteristics were analyzed and the optimum cutting conditions with materials were established.

• 한국정밀공학회지
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• 제23권4호
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• pp.91-98
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• 2006

A light guide panel (LGP) is an element of the LCD back light unit, which is used for display devices. In this study, the laser marking process is applied to the fabrication of light guide panels as the new fabrication process. In order to obtain a light guide panel which has high luminance and uniformity, four principal parameters such as power, scanning speed, ratio of line gap, and number of line were selected. A Web-based design tool was developed to generate patterns of light guide panel at any location, and the tool may assist the designer to develop optimized patterns. Topcon-BM7 was used for luminance measurement of each specimen with $100mm{\times}100mm$ area. By Taguchi method optimized levels of each parameters were found, and luminance of $3523cd/cm^2$ and uniformity of 92% were achieved using the laser machined BLU.

• Korean Chemical Engineering Research
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• 제48권6호
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• pp.737-740
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• 2010

높은 누설 전류와 문턱 전압의 이동은 비정질 실리콘(a-Si:H) 트랜지스터(TFT)의 단점이다. 이러한 특성은 게이트 절연체와 활성층 박막의 막 특성, 표면 거칠기와 공정 조건에 따라 영향을 받는다. 본 연구의 목적은 누설 전류와 문턱 전압의 특성을 개선하는데 목적이 있다. 게이트 절연체의 공정 조건에 대해서는 질소를 증가한 증착 공정 조건을 적용하였고, 활성층의 공정 조건에 대해서는 산소를 증가한 공정 조건을 적용하여 전자 포획을 감소시키고 박막의 밀도를 증가시켰다. $I_{off}$는 $65^{\circ}C$ 조건하에서 1.01 pA에서 0.18pA로, ${\Delta}V_{th}$는 -1.89 V에서 -1.22V로 개선되었다.

• 한국세라믹학회지
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• 제39권7호
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• pp.675-679
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• 2002

강화유리를 제조하기 위해서, 디스플레이 기판으로 사용되는 soda-lime-silicate 유리를 대상으로 단일이온교환 특성에 대하여 3점곡강도와 잔류응력을 조사하였다. 단일이온교환을 47$0^{\circ}C$에서 1시간 처리 후, 45$0^{\circ}C$에서 24시간 행하였을 때, 62.5$\times$10$_{6}$ kg/$m^2$의 최대 강도 값을 나타내었다. 또한, 곡강도 측정 후 얻어진 시편의 파단면에 존재하는 잔류응력층을 파괴분석을 통하여 관찰한 결과, 이 잔류응력층이 외부하중에 대한 탄성 변형에너지를 흡수하여 유연성을 증가시킴을 알 수 있었다 또한, 탄성변형에너지 흡수는 만곡변화, 균열가지수 및 취성특성 분석에서도 관찰되었다.