• Title/Summary/Keyword: S-Glass

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A Study on the Thermal Stresses of the Glass Lens Mold Using in Progressive GMP Process (순차이송 GMP 방식용 유리렌즈 금형의 열응력에 관한 연구)

  • Chang, S.H.;Lee, Y.M.;Shin, G.H.;Yoon, G.S.;Jung, W.C.;Jung, T.S.;Heo, Y.M.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2007.10a
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    • pp.289-292
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    • 2007
  • To prevent the damage of glass lens molds and deterioration of glass lenses using in progressive GMP process, a thermal stress and a deformation of the glass lens molds at forming temperature should be considered in the design step. In this study, as a fundamental study to develop a multi cavity mold used in an aspheric glass lens molding, a heat transfer and a thermal stress analysis were carried out for the case of one cavity glass lens mold used in progressive GMP process. Finally, using analysis results, we estimated the thermal stress in a glass lens mold and predicted a modified height of guide ring that determines the forming height of a glass lens.

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Analysis on Glass-Bead Type Retroreflector's Optical Characteristics (유리구슬형 재귀반사기의 광학적 특성 해석)

  • Lee, E.H.
    • Journal of the Korean Society for Precision Engineering
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    • v.11 no.4
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    • pp.165-173
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    • 1994
  • Retroreflector is different from other reflecting surfaces as it mades reflection in which radiation is returned in directions close to its incoming direction. Because of this characteristics, retroreflectors find many applications in traffic safety related areas. Retroreflectors are usually made using comer cubes, or partially coated glass beads. These glass beads can be made very small, so that they can be coated on sheets or mixed with paints. The design of glass type retroreflector depends on glass bead's shape and material, and its optical characteristics are related to the refractive index of glass. In this paper, a method of anlyzing glass bead type retroreflector's sptical characteristics with respect to shape and optica property of the glass, is presented. First, the coefficient of retroreflection, which is a measure of retroreflector's optical characteristics, is derived analytically using geometrical optics method. And the result is plotted using numerical methods. The results show good match with those obtained experimentally, which were supplied from a commercial retroreflector manufacturer.

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The Preparation of Glass Beads (Glass beads 제조에 관하여)

  • Jin Il Kim
    • Journal of the Korean Chemical Society
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    • v.17 no.3
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    • pp.198-206
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    • 1973
  • We produced the glass beads using a spherical vessel which is rotable with the mix ture of releasing agent and glass powder in a electric furnace (apparatus 1), a tubing apparatus of electric furnace which can be gravitated a cullet (apparatus 2) and a tubing apparatus which is dispersible glass powders with the flame of propane gas (apparatus 3). The substrates which are Korean sodium silicates glass 1, 2, boro silicates glass and lead silicates glass are used and the size of cullets is 60-300 mesh. In the results of experimental apparatus, the preferable temperature of apparatus 1 is 880$^{\circ}C$, apparatus 2 is 980$^{\circ}C$ and apparatus 3 is 1100$^{\circ}C$. However, the method of apparatus 3 is more effective than the methods of apparatus 1 and 2 in view of treating time and rate of adhesion.

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Development of Sealing Technology for Far-Infrared Multispectral ZnS Using Chalcogenide Glass Material

  • Soyoung Kim;Jung-Hwan In;Karam Han;Yoon Hee Nam;Seon Hoon Kim;Ju Hyeon Choi
    • Korean Journal of Materials Research
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    • v.32 no.12
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    • pp.515-521
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    • 2022
  • Various types of optical materials and devices used in special environments must satisfy durability and optical properties. In order to improve the durability of zinc sulfide multispectral (MS ZnS) substrates with transmission wavelengths from visible to infrared, Ge-Sb-Se-based chalcogenide glass was used as a sealing material to bond the MS ZnS substrates. Wetting tests of the Ge-Sb-Se-based chalcogenide glass were conducted to analyze flowability as a function of temperature, by considering the glass transition temperature (Tg) and softening temperature (Ts). In the wetting test, the viscous flow of the chalcogenide glass sample was analyzed according to the temperature. After placing the chalcogenide glass disk between MS ZnS substrates (20 × 30 mm), the sealing test was performed at a temperature of 485 ℃ for 60 min. Notably, it was found that the Ge-Sb-Se-based chalcogenide glass sealed the MS ZnS substrates well. After the MS ZnS substrates were sealed with chalcogenide glass, they showed a transmission of 55 % over 3~12 ㎛. The tensile strength of the sealed MS ZnS substrates with Ge-Sb-Se-based chalcogenide glass was analyzed by applying a maximum load of about 240 N, confirming its suitability as a sealing material in the far infrared range.

Analytical Quantification and Effect of Microstructure Development in Thick Film Resistor Processing

  • Lee, Byung Soo
    • Journal of the Microelectronics and Packaging Society
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    • v.19 no.4
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    • pp.33-37
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    • 2012
  • Microstructure developments of $RuO_2$ based thick film resistors during firing as a function of glass viscosity were analytically quantified and its effect on the electrical property was investigated. The microstructure development was retarded as the viscosity of glass was increased. It was found that the viscosity range for each stage of microstructure development are as follows ; $7500-10^5Pa{\cdot}s$ for the glass sintering, $2000-7500Pa{\cdot}s$ for the glass island formation, $700-2000Pa{\cdot}s$ for the glass spreading, and $50-700Pa{\cdot}s$ for the infiltration. The sheet resistivity decreased as the viscosity of glass in the resistor film increased due to the higher chance of sintering for the conductive particles with the higher viscosity of the glass.

Effects of Physical Properties of Glass on the TCR of $RuO_2$ Thick Film Resistors for Hybrid Integrated Circuits (HIC) (HIC용 $RuO_2$ 후막저항체에서 유리의 물리적 성질이 TCR에 미치는 영향)

  • Lee, B.S.;Lee, J.
    • Journal of the Korean Ceramic Society
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    • v.30 no.11
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    • pp.974-978
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    • 1993
  • Glass viscosity effects on the electrical properties and microstructure of RuO2 based thick film resistors (TFR) using alumina modified lead borosilicate glasses were studied. AT 85$0^{\circ}C$, the glass viscosities were increased from 4.24Pa.s to 51.5Pa.s when the alumina was added from none to 14 weight percent to the standard glass of 63% PbO, 25% B2O3 and 12% SiO2. The resistivities of resistors were generally decreased and the microstructure development was retarded as the viscosity of the glass increased. This is contrary to the generally accepted thought that the low resistivity is due to fast microstructure development kinetics in TFR. Even though the glass viscosity retards the microstructure development kinetics, the overall network formations are favored for higher viscosity of glass, such that the sheet resistivities were decreased as the glass viscosity increased.

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Physical Properties and Preparation of HDPE Filled with Microencapsulated Glass Beads (마이크로 캡슐화된 Glass bead 충전 HDPE 복합재의 제조와 물리적 성질)

  • Kim, Dong-Kook;Kim, Kwang-Ho;Im, Seung-Soon;Noh, Si-Tae
    • Applied Chemistry for Engineering
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    • v.3 no.3
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    • pp.430-439
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    • 1992
  • To improve the adhesion of interface and dispersion of glass beads in the composite, HDPE filled with glass brads, we encapsulated the g1ass beads with polymer by phase separation method using complex coacervation in organic solvent. EMAA and EAA were used as the polymeric wall materials. The microencapsulation efficiency and morphology were observed by thermogravimetric analysis and SEM, respectively. And also we investigated the physical and dynamic mechanical properties of the composite as the function of the beads contents and microencapsulation efficiency. Compared with the composite containing non-treated glass beads, the decrease in tensile strengthe of the composites containing the encapsulated glass beads become markedly small, and about 30~40% Increase in tensile modulus was observed. From the results of the dynamic mechanical analysis, it was found that the adhesion of interface and dispersion could be improved upon encapsulation.

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Optimization for the Natural Frequency of the TFT-LCD Glass Plate with Multi-Support Point (다점지지된 TFT-LCD 유리기판의 고유진동수 최적화)

  • Lee, H.S.;Lee, Y.S.;Kim, H.S.;Lee, J.W.;Lee, S.H.
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.05a
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    • pp.246-249
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    • 2005
  • The TFT-LCD is extensively used from a small watch to a large TV display, and the demand is increasing rapidly. The size of R-LCD glass plate becomes more bigger, and the thickness become more thinner with high demands. As a result natural frequency of the TFT-LCD glass plate becomes more lower. The TFT-LCD glass plate will be moved by robot arm and may receive effect of vibration that occur at transfer. Natural frequency of the TFT-LCD glass plate is increased or decrease according to location that robot arm fixs glass plate. Purpose of a this study is finding support location that optimize the first natural frequency of TFT-LCD glass plate. The size optimization method of ANSYS 8.0 is used as the optimization tool search on the optimal support location of TFT-LCD glass plate. The considered number of support point is from 4 to 9.

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Phase Separation and Precipitation Characteristics in ZnS doped Borosilicate Glasses (ZnS 미립자 분산 붕규산엽계 유리에서의 분상 및 미립자 석출 특성)

  • 이승환;류봉기
    • Journal of the Korean Ceramic Society
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    • v.35 no.12
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    • pp.1337-1342
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    • 1998
  • To investigate an effect of phase separation on precipitation characteristics of ZnS microcrystals in ma-trix glass ZnS doped borosilicate glasses for nonlinear optical applications were prepared by melting and pre-cipitation process. ZnS dopant contributed to phase separation promotion which increased the phase separa-tion of the matrix glass within immiscibility region. It was also found that ZnS as phase separation promoter showed a similar contribution for some selected glass compositions in miscibility region. The precipitation of ZnS microcrystals occurred in thephase separable glass compoitions. The radius of ZnS microcrystals in-creased with increasing the heat treatment temperature and Na2O contents of matrix glass composition. The ZnS particle sizes estimated by effective mass approximation ranged from about 30 to 80${\AA}$ It was suf-ficiently small to show quantum confinement effect.

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A study on the sintering and dielectric properties by softening point of glass in low temperature sinterable glass-ceramics (저온 소성용 Glass-Ceramics에서 glass의 softening point에 따른 소결 및 유전 특성 연구)

  • Yoon, Sang-Ok;Oh, Chang-Yong;Kim, Kwan-Soo;Jo, Tae-Hyun;Park, Jong-Guk
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.11a
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    • pp.396-399
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    • 2004
  • 저온 동시소성용 glass-ceramics의 소결 경향성 연구를 위해 lead-borosilicate계 glass를 frit화하여 알루미나분말과 $TiO_2$분말을 $10{\sim}50\;vol%$로 각각 혼합한 후 여러 온도에서 소결하여 소결과 유전 특성을 조사하였다. 그 결과 glass의 연화온도(Ts)가 낮을수록 최대 치밀화 온도가 낮았으며, 반면에 소결밀도는 Ts가 높을수록 높았는데, 이는 glass-ceramicss에서의 결정화도와 관계하였다. 본 연구를 통해 glass-ceramic에서의 소결특성은 glass와 ceramic의 반응성에 의한 2상 석출 정도에 큰 영향을 받음을 알 수 있었으며, ceramic filler로서 알루미나와 $TiO_2$를 이용하여 $900^{\circ}C$에서 소성이 가능하였다. 알루미나의 경우 유전특성$({\epsilon}r=8.5,\;Q{\times}fo=6000)$이 기판용 저유전율 재료로 사용이 가능하였고, $TiO_2$의 경우도 유전특성($({\epsilon}r=17,\;Q{\times}fo=4000)$)이 필터용 고유전율 재료로 사용 가능하도록 높게 나타났다.

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