• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.146-147
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• 2011

Processing a large area substrate for liquid crystal display (LCD) or solar panel applications in a capacitively coupled plasma (CCP) reactor is becoming increasingly challenging because of the size of the substrate size is no longer negligible compared to the wavelength of the applied radio frequency (RF) power. The situation is even worse when the driving frequency is increased to the Very High Frequency (VHF) range. When the substrate size is still smaller than 1/8 of the wavelength, one can obtain reasonably uniform process results by utilizing with methods such as tailoring the precursor gas distribution by adjustingthrough shower head hole distribution or hole size modification, locally adjusting the distance between the substrate and the electrode, and shaping shower head holes to modulate the hollow cathode effect modifying theand plasma density distribution by shaping shower head holes to adjust the follow cathode effect. At higher frequencies, such as 40 MHz for Gen 8.5 (2.2 m${\times}$2.6 m substrate), these methods are not effective, because the substrate is large enough that first node of the standing wave appears within the substrate. In such a case, the plasma discharge cannot be sustained at the node and results in an extremely non-uniform process. At Applied Materials, we have studied several methods of modifying the standing wave pattern to adjusting improve process non-uniformity for a Gen 8.5 size CCP reactor operating in the VHF range. First, we used magnetic materials (ferrite) to modify wave propagation. We placed ferrite blocks along two opposing edges of the powered electrode. This changes the boundary condition for electro-magnetic waves, and as a result, the standing wave pattern is significantly stretched towards the ferrite lined edges. In conjunction with a phase modulation technique, we have seen improvement in process uniformity. Another method involves feeding 40 MHz from four feed points near the four corners of the electrode. The phase between each feed points are dynamically adjusted to modify the resulting interference pattern, which in turn modulate the plasma distribution in time and affect the process uniformity. We achieved process uniformity of <20% with this method. A third method involves using two frequencies. In this case 40 MHz is used in a supplementary manner to improve the performance of 13 MHz process. Even at 13 MHz, the RF electric field falls off around the corners and edges on a Gen 8.5 substrate. Although, the conventional methods mentioned above improve the uniformity, they have limitations, and they cannot compensate especially as the applied power is increased, which causes the wavelength becomes shorter. 40 MHz is used to overcome such limitations. 13 MHz is applied at the center, and 40 MHz at the four corners. By modulating the interference between the signals from the four feed points, we found that 40 MHz power is preferentially channeled towards the edges and corners. We will discuss an innovative method of controlling 40 MHz to achieve this effect.

• Proceedings of the KAIS Fall Conference
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• 2005.05a
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• pp.159-162
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• 2005

전자빔을 이용하던 CRT(Cathode Ray Tube) 모니터에서 픽셀단위의 LCD(Liquid Crystal Display) 디스플레이 사용으로 휴대용 정보처리 장치들은 급속한 발전을 이루게 되었다. 기존의 CRT 모니터에서 전자빔을 사용하던 방식에서 픽셀(Pixel) 단위의 후면발광 디스플레이를 만들면서 CRT 모니터보다 빠른 응답특성을 나타내며 저 전력일 뿐만 아니라 디스플레이의 두께도 줄일 수 있게 되었다. 휴대가 가능한 디스플레이의 발전으로 노트북이나 PDA와 같은 실시간 정보를 활용 및 처리 할 수 있는 방법들을 제시할 수 있었지만 원활한 활용을 위해 더 적은 전력을 사용하는 방법들이 제시되어야 했다. 이에 따라 저 전력 소모, 빠른 응답특성, 넓은 시야각 그리고 경량화가 가능한 디스플레이가 되기 위한 새로운 디스플레이가 선을 보이게 되었다. 현재 차세대 디스플레이로 각광을 받고 있는 디스플레이 소자로는 OLED(Organic Light Emitting Diode)가 있다 이는 LCD 디스플레이가 가지고 있는 단점을 보완하여 우선적으로 높은 색도가 가능하며 후면발광을 사용하지 않고 자체 발광을 하기 때문에 저 전력 소모가 현실화되었다. 또한 디스플레이의 유동성이 가능하여 휘어질 수 있는 특성을 가지고 있다. 그러나 이러한 유기발광 소자의 경우 높은 발광 효율을 위한 구조적 개선이 필요하며 소자의 수명도 개선해야 한다. 이에 따라 유기발광 소자의 메카니즘에 대한 파악이 필요하게 되며 물리적 구조에 대한 이해가 필요하다. 이를 위해 물리적, 수치적 해석으로 소자의 특성을 파악해 줌으로써 개선된 유기발광 소자 제작이 가능 할 것이다.기에 대한 영향정도를 측정하여 정량적으로 도출하였다. 이를 각 구간에 대해 상호 비교 분석함으로써 대형국책사업에서의 공기지연인자에 대한 분석 방법론을 정립하였고 공기지연 분석 방법론의 현실적 적용을 위한 제언과 그에 따른 개선사항에 대해 도출하였다.있는 발판을 마련하게 된다고 추정하였다. 0.5%가 control사이에서 0.95로 가장 색차가 크게 나타났으며, 그 다음이 냉동분쇄 0.5% 0.83으로 나타나 송이의 첨가율이 높을수록 색차가 크게 나타나는 것을 알 수 있다. 색차가 가장 낮은 제품은 법동분쇄 0.3%, 동결건조 0.3%로 나타났다. 송이양갱의 색(color), 냄새(flavor), 맛(taste), 외관(appearances), 질감(viscosity), 종합적 평가(overall acceptability) 등의 관능평가를 실시한 결과 중 색에 대한 기호도는 냉동분쇄 0.1% 송이양갱이 가장 높은 것으로 나타났으나, 집단간 유의한 차이는 나타나지 않았고, 냄새는 동결건조 0.1%의 송이양갱이 3.38로 가장 점수가 높았으며, 냉동분쇄 0.3%의 송이양갱이 2.81로 가장 낮은 기호도를 나타내었다. 맛에서는 p<0.01수준에서 집단간 유의한 차이를 나타내었는데, 동결건조 0.1%가 그 중 가장 높은 기호도를 나타내었으며, 그 다음이 동결건조 0.5%였다. 가장 낮은 선호도를 나타낸 것은 열풍건조 0.5%였다. 질감은 P<.05 수준에서 집단간 유의미한 차이를 나타내었으며 동결건조 0.1%가 가장 높은 기호도를 나타내었으며, 동결건조 0.5%함유 송이양갱이 1.21로서, 현저히 낮은 기호도를 나타내었다. 종합적인 평가에서는 동결건조 0.1%함유

• Korean Chemical Engineering Research
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• v.53 no.2
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• pp.181-192
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• 2015

The aim of this study is to obtain optimum process condition for using two tower distribution to recycle the waste Propylene Glycol Monomethyl Ether Acetate (PGMEA) that is formed after washing LCD. The optimum process condition for the content of PGMEA, which is dependent variable, at 1st distillation was calculated according to Bottom temperature (BTM temperature), Reflux amount, Feed amount, Feed temperatures, and the optimum process conditions and optimum factors for the content of PGMEA at 2nd distillation according to Bottom temperature (BTM temperature), Reflux amount, Feed amount, Feed temperatures. At 1st distillation, Reflux amount, Feed amount, and Feed temperature are significant variables. However, it is found that the BTM temperature range is not significant in the range of process condition used in this study. The optimum process conditions are based on $5700{\ell}$ of Feed amount, $2500{\ell}$ of Reflux amount, $165^{\circ}C$ of BTM temperature, and $130^{\circ}C$ of Feed temperature. For the this condition, the predicted content of PGMEA was calculated as 92.12~94.62%. Significant factors at 2nd distillation are Reflux amount, Feed amount, and BTM temperature. Multicollinearity is between Reflux amount and BTM temperature. BTM was omitted in the multiple regression equation because there is a strong positive correlation between Reflux amount and BTM temperature. Base on $199^{\circ}C$ of BTM temperature, The optimum process conditions are based on $4275{\ell}$ of Feed amount, $6200{\ell}$ of Reflux amount and $130^{\circ}C$ of Feed temperature. In this condition, the predicted content of PGMEA was calculated as 99.0~99.5%.

• Korean Journal of Optics and Photonics
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• v.18 no.6
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• pp.432-440
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• 2007

Optical simulation methods such as a ray tracing technique have been widely used to predict the optical performances of collimating films for LCD backlight applications. It is necessary to optimize simulation conditions which have substantial effect on the simulation result in order to predict accurate performances of collimating films. We have set up a very simple backlight model consisting of a reflection film, a virtual flat light-source, and a prism film, which is a representative collimating film for backlight, in order to analyze the simulation conditions which are strongly correlated with the on-axis luminance gain and the viewing-angle characteristics of prism films. It was found that the dependence of the relative change in the on-axis luminance on the structure and material properties of collimating films can be derived from the above-mentioned simple BLU model and from simulation using it. However, the exact reflection property of the reflection film and the distribution of the incident light onto the optical film were found to be very important for revealing exact viewing-angle characteristics of collimating films.

• Korean Journal of Optics and Photonics
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• v.21 no.2
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• pp.61-68
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• 2010

Optical simulation methods were applied to the edge-lit LED backlight for LCD TV applications in order to optimize the optical structure of the light guide plate(LGP), and thus to improve the uniformity properties by removing the bright spots caused by LED's. The edge-lit LED backlight consisted of three white LED's with a lamp cover, a light guide plate, and a reflection film. When there was no pattern on the entrance side surface of the LGP, the illuminance uniformity was sensitively dependent on the distance d between the LED and the entrance surface. The illuminance uniformity increased with d but its increasing rate slowed down when d was beyond ~ 1.5 mm. When micro-patterns such as a lenticular lens array (LLA) or a serration pattern were formed on the entrance surface, the illuminance uniformity was improved substantially even for the case of very small d. At the same simulation condition, the lightguide with serration pattern showed a better uniformity than that with LLA pattern. Additional improvement could be achieved by changing the refractive index of the micro-patterns. These results suggest that using micro-patterns is a very effective way to reduce the bright spots due to their refracting function for the concentrated incident rays onto the LGP.

• 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$.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.72-72
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• 2000

ITO(Indium-Tin-Oxide)는 n-type 전도 특성을 갖는 산화물 반도체로서 가시광 영역에서의 높은 광투과율 및 낮은 전기 비저항을 나타내기 때문에 태양전지, 액정디스플레이(liquid crystal display), 터치스크린(touch screen) 등의 투명전극 재료, 전계 발광(electroluminescent) 소자, 표면발열체, 열반사 재료 등 다양한 분야에 응용되고 있다. 본 연구에서는 타겟 제작에 드는 비용을 줄이고, 타겟 이용의 효율성을 높이기 위해 기존의 세라믹 타겟 대신 분말 타겟을 사용하여 유리 기판 상에 ITO 박막을 DC magnetron sputtering법에 의해 제조하고, 열처리 온도 및 열처리 분위기에 따른 ITO 박막의 전기적 광학적 특성을 조사하였다. 열처리 온도가 10$0^{\circ}C$이하인 경우 열처리하지 않은 시편과 동일하게 In2O3의 (411)면에 해당하는 peak가 관찰되었다. 그러나 20$0^{\circ}C$의 온도로 열처리 할 경우 (411)면 peak의 세기는 상대적으로 감소하고 대신 이전에 나타나지 않았던 (222)면에 대응하는 peak 세기가 현저하게 증가함을 알 수 잇다. 이것은 ITO 박막의 경정성장이 열처리 전 (411)면 방향으로 이루어지나 20$0^{\circ}C$의 온도로 열처리 후 재결정화에 의해 (222)면 방향으로의 우선방위를 갖고 성장함을 의미한다. 또한 주로 높은 기판온도에서 관찰되었던 (211), (400), (411), (440), (622)면 등에 해당하는 peak가 나타남을 볼 수 있었다. 열처리 온도를 더욱 증가시킴에 따라 결정구조에는 큰 변화 없이 (222)면 peak 세기가 증가하였다. 한편 열처리 온도를 더욱 증가시킴에 따라 (222)면 peak 세기가 상대적으로 조금 감소할뿐 XRD회절 결과에는 큰 변화를 관찰할 수 없었다. 이러한 결과로부터 기판을 가열하지 않고 증착한 ITO 박막의 재결정화에 필요한 최소의 열처리 온도는 20$0^{\circ}C$이며, 그 이상의 열처리 온도는 ITO박막의 결정구조에 큰 영향을 미치지 않음을 알 수 있었다. 열처리 전 비저항은 1.1$\times$10-1 $\Omega$-cm 의 값을 가지거나 10$0^{\circ}C$의 온도로 열처리함에 따라 9.8$\times$102$\Omega$-cm 로 약간 감소하였다. 열처리 온도를 20$0^{\circ}C$로 높임에 따라 비저항은 급격히 감소하여 1.7$\times$10-3$\Omega$-cm의 최소값을 나타내었다. 열처리 온도가 10$0^{\circ}C$인 경우 가시광 영역에서의 광투과율은 열처리하지 않은 시편과 비교해 볼 때 약간 증가하였다. 열처리 온도는 20$0^{\circ}C$로 증가시킴에 따라 투과율은 크게 향상되어 흡수단 이상의 파장영역에서 90% 이상의 투과율을 나타내었다. 이러한 광투과율의 향상은 앞서 증착된 ITO 박막이 열처리 중 재결합에 의해 우선 성장 방위가 (411)면 방향에서 (222)면 방향으로 변화되었기 때문으로 생각된다. 그러나 열처리 온도를 20$0^{\circ}C$이상으로 증가시켜도 광투과율은 큰 변화를 나타내지 않았다.

• Journal of the Society of Disaster Information
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• v.15 no.2
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• pp.239-248
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• 2019

Purpose: This study aims to enhance the resistance against sulfate attack compared to ordinary Portland cement (OPC) concrete by using liquid crystal display (LCD) as binder. Method: The fundamental properties including compressive strength and porosity of concrete replaced by LCD up to 15% at increments of 5% and in turn, the weight, volume, and strength loss of LCD-mixed concrete was analyzed. Results: For the concrete substituted by 5% of LCD, it showed the highest compressive strength at 28 days of curing, and particular at immersion of $Na_2SO_4$ solution, it was achieved the lowest loss of weight, volume and strength due to an decreased porosity at capillaries. In contrast, there is no distinct difference of the sulfate attack resistance between LCD-mixed concretes under exposure of $MgSO_4$ solution, excepted for OPC concrete. Conclusion: In this study, comparison of resistance to sulfate attack between LCD-mixed concretes, and it would be proposed the possibility of LCD usage as binder through long-term verification with extended replacement ratio and identification of changes of hydrates in the cement matrix.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.32 no.1
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• pp.10-20
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• 2022

Objectives: The aim of this study is to evaluate exposure levels of the extremely low frequency magnetic fields(ELF-MF) radiated from various electric facilities in Liquid Crystal Display(LCD) manufacturing processes. Methods: This study measured the exposure levels of personal and local ELF-MF for the electronic facilities installed in two LCD manufacturing companies. Samplers were installed around workers' waist during working hours to identify personal exposure levels, and direct reading equipment were located at 3 cm, 10 cm, and 30 cm away from the surface of the electronic facilities to measure local exposure levels. Average and maximum(ceiling) values were calculated for personal and local exposure levels. Results: Average and maximum of personal exposure levels for each worker were 0.56(mean) ± 0.02(SE) µT and 6.31 ± 0.75 µT, respectively. Statistical analyses of the study found that maximum of the personal exposure levels for engineers was significantly higher than that for operators since engineers spend more time near the electronic facilities for repairing. The range of maximum personal exposure levels was 0.50 ~ 43.50 µT and its highest level was equivalent to 4.35 % of ACGIH(American Conference of Governmental Industrial Hygienists) exposure limit value(1 mT). Maximum of local exposure levels was 8.18 ± 0.52 µT and the electronic facilities with higher exposure levels were roof rail and electric panel, which were not related to direct manufacturing. The range of maximum local exposure levels was 0.60 ~ 287.20 µT and its highest level was equivalent to 28.7 % of the ACGIH exposure limit value. Lastly, the local exposure levels significantly decreased as the measurement distance from the electronic facilities increased. Conclusions: Maximum of personal and local exposure levels did not exceed the exposure limit value of ACGIH. However, it is recommended to keep the workers as far as possible from the sources of ELF-MF.

• The Journal of the Convergence on Culture Technology
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• v.10 no.3
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• pp.13-17
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• 2024

A color sensor is an optical sensor used to take pictures of objects, including the human body, and reproduce them on a monitor. A color sensor quantifies the red, green, and blue light coming from an object and expresses it as a digital number, and can judge the state of the object by comparing the values ​​or the ratio.In this study, the standard colors displayed on the monitor were measured using a color sensor, and the magnitudes of the red, green, and blue components, or RGB values, were compared with the values ​​indicated by the computer. When measured with the TCS 34725 color sensor, even when the light generated by the computer consists of only one or two of red, green, and blue light, the color sensor detected all three components. Additionally, when the colors of two monitors with the same RGB values ​​were measured using a color sensor, different RGB values ​​were measured. These results can be attributed to the imperfection of the color filters used to express colors on the monitor and the imperfect optical characteristics of the photodiodes used in the color sensor. When photographing an object and judging its condition based on its color, you must use the same type of camera or smartphone.