• Journal of the Semiconductor & Display Technology
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• v.6 no.4
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• pp.33-38
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• 2007

Quartz glass panel was prepared by a colloidal silica through the heat-treatment only without any additives in wet-chemical method. This colloidal silica used in slurry process has the uniform distribution of particle size and lower cost. The results show that 6N as a degree of purity and the 86 percentage of violet transmittance in 1mm thickness. AFM(Atomic Force Microscopy) pattern shows that the surface roughness are less than lnm. Also, we investigated the characteristic of quartz panel according to the concentration and distribution of hydroxyl group, viscosity and thermal expansion coefficient.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.12
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• pp.1107-1113
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• 2014

In this article, the megasonic cleaning system for cleaning micro/nano particles from flat panel display (FPD) surfaces was developed. A piezoelectric actuator and a waveguide were designed by finite element method (FEM) analysis. The calculated peak frequency value of the quartz waveguide was 1002 kHz, which agreed well with the measured value of 1003 kHz. The average acoustic pressure of the megasonic cleaning system was 43.1 kPa, which is three times greater than that of the conventional type of 13.9 kPa. Particle removal efficiency (PRE) tests were performed, and the cleaning efficiency of the developed system was proven to be 99%. The power consumption of the developed system was 64% lower than that of the commercial system. These results show that the developed megasonic cleaning system can be an effective solution in particle removing from FPD substrate with higher energy efficiency and lower chemical and ultra pure water (UPW) consumption.

• Journal of the Korean Ceramic Society
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• v.46 no.3
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• pp.306-312
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• 2009

The size of various alumina ceramics used in semiconductor and display industry is also required to increase with increase in wafer and panel size. In this research, large alumina ceramics was fabricated by filter pressing of alumina slurry using commercial powder and thereafter sintering at $1600^{\circ}C$ in gas furnace. The characteristics of large alumina ceramics thereby were compared to those of small alumina ceramics prepared by pressure forming such as uniaxial pressing and CIP. Careful control of properties of alumina slurry and filter pressing made the fabrication of large alumina ceramics possible, and its characteristics were equivalent to those of small alumina ceramics. The large alumina ceramics, prepared by sintering the green body of 63% relative density at $1600^{\circ}C$, exhibited both dense microstructure corresponding to 98.5% of relative density and 99.8% of high purity as in starting powder.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.29 no.2
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• pp.61-70
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• 2019

Geopolymer is an eco-friendly construction material that has various advantages such as reduced $CO_2$ emission, fire resistance and low thermal conductivity compared to cement. However, it has not been many studies on the thermal behavior of the surface of the geopolymer panel when flame is applied to the surface. In this study, surface characteristics of hardened geopolymer on flame exposure was investigated to observe its characteristics as heat-resistant architectural materials. External structure changes and crack due to the heat shock were not observed during the exposure on flame. According to the residue of calcite and halo pattern of aluminosilicate gel, decarboxylation and dehydration were extremely limited to the surface and, therefore, it is thought that durability of hardened geopolymer was sustained. Gehlenite and calcium silicate portion was inversely proportional to quartz and calcite and significantly directly proportional to BFS replacement ratio. Microstructure changes due to the thermal shock caused decarboxylation and dehydration of crystallization and it was developed the pore and new crystalline phase like calcium silicate and gehlenite. It is thought that those crystalline phase worked as a densification and strengthening mechanism on geopolymer panel surface.

• Aerospace Engineering and Technology
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• v.2 no.2
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• pp.45-49
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• 2003

A Bake-Out test for STSAT-1 FM(Flight Model) was performed in a Bake-Out Chamber at SITC(Satellite Integration & Test Center) in KARI(Korea Aerospace Research Institute). The purpose of this test is to measure and analyze the outgassing rate to affect the optical equipment(FIMS) and to eliminate contaminants through the high temperature bake-out. This Bake-Out test is composed of three parts which are honeycomb panels & harnesses(Batch 1), an assembled satellite(Batch 2), and a disassembled satellite(Batch 3). For each test, quantitative and qualitative measurements and analysis were performed using TQCM(Thermoelectric Quartz Crystal Microbalance) and RGA(Residual Gas Analyzer.)

• Proceedings of the KIEE Conference
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• 2008.09a
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• pp.235-236
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• 2008

Charging of spacecraft occurs in plasma and radiation environment. Especially, we focused on an accident caused by internal charging in a glass material that was used as the cover plate of solar panel array, and tried to measure the charge distribution in glass materials under electron beam irradiation by using a PEA (Pulsed Electro-Acoustic method) system. In the case of a quartz glass (pure $SiO_2$), no charge accumulation was observed either during or after the electron beam irradiation. On the contrary, positive charge accumulation was observed in glass samples containing metal-oxide components. It is found that the polarity of the observed charges depends on the contents of the impurities. To identify which impurity dominates the polarity of the accumulated charge, we measured charge distributions in several glass materials containing various metal-oxide components and calculated the trap energy depths from the charge decay characteristics of all glass samples.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.2305-2306
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• 2008

Charging of spacecraft occurs in plasma and radiation environment. Especially, we focused on an accident caused by internal charging in a glass material that was used as the cover plate of solar panel array, and tried to measure the charge distribution in glass materials under electron beam irradiation by using a PEA (Pulsed Electro-Acoustic method) system. In the case of a quartz glass (pure $SiO_2$), no charge accumulation was observed either during or after the electron beam irradiation. On the contrary, positive charge accumulation was observed in glass samples containing metal-oxide components. It is found that the polarity of the observed charges depends on the contents of the impurities. To identify which impurity dominates the polarity of the accumulated charge, we measured charge distributions in several glass materials containing various metal-oxide components and calculated the trap energy depths from the charge decay characteristics of all glass samples.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.692-696
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• 2005

In an attempt to fabricate all inclusive display systems we are presenting a study on several elements that would be used as building blocks for all-on-board integrated applications on stainless steel foils. These systems would include in the same substrate all or many of the components needed to drive a flat panel OLED display. We are reporting results on both digital and analog circuits on stainless steel foils. Shift registers running at speeds greater than 1.0MHz are shown as well as oscillators operating at over 40MHz. Pixel circuits for driving organic light emitting diodes are presented. The device technology of choice is that based on poly-silicon TFT technology as it has the potential of producing circuits with good performance and considerable cost savings over the established processes on quartz or glass substrates (amorphous Silicon a-Si:H or silicon on Insulator SOI).

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2005.05a
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• pp.219-223
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• 2005

Nowadays laser cutting is the most promising method of cutting FPD(Flat Panel Display) glass in mass-production line. And this method can also be used to cut other brittle materials such as quartz, sapphire, ceramic and semiconductor The concept of this method is shown in picture 1. Laser beam heats glass up to strain point, not to melting point and cooling system chills glass to induce maximun thermal stress in glass surface and then the thermal stress generates micro thermal crack, in other words blind depth of crack, along laser beam and cooling line.

• Proceedings of the KAIS Fall Conference
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• 2006.11a
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• pp.272-275
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• 2006

본 논문에서는 CMP(Chemical Mechanical Polishing) 슬러리용으로 사용되는 저가이면서 입도 분포가 균일한 콜로이달 실리카(Colloidal Silica)를 사용하여 추가의 첨가제 없이 열처리 공정만을 거쳐 석영유리를 제조하여 6N의 순도와 1 mm 두께 기준 86%의 자외선 투과율 그리고 AFM(Atomic Force Microscopy) 및 간섭계 현미경을 이용하여 표면의 거칠기가 1 nm 미만인 고순도 석영유리를 제조하였다.