• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2007년도 추계학술대회 논문집
• /
• pp.289-292
• /
• 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.

• 한국정밀공학회지
• /
• 제11권4호
• /
• pp.165-173
• /
• 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.

• 대한화학회지
• /
• 제17권3호
• /
• pp.198-206
• /
• 1973

이형제와 유리분말의 혼합물을 회전시킬 수 있는 원형전기로 장치(장치 1), 유리분말을 자유낙하 시킬 수 있는 관형 전기로 장치 (장치 2) 및 유리분말을 propane gas의 화염과 함께 분사시킬수 있는 관형장치 (장치 3)를 사용하여 glass beads를 제조하였다. 사용한 기재는 한국산 sodium silicates glass 1,2, boro silicates glass 및 lead silicates glass 이며 cullet의 크기는 60mesh-300mesh이다. P.G.를 기재로 하여 이들 장치에 의하여 glass beads를 제조할 경우, 장치 1의 최적온도는 880$^{\circ}C$이고 장치 2의 최적온도는 980$^{\circ}C$이며 장치 3의 최적온도는 1100$^{\circ}C$이었다. 그렇지만 처리시간과 응착률 등으로 보아 장치 3의 방법이 가장 효율적이었다.

• 한국재료학회지
• /
• 제32권12호
• /
• pp.515-521
• /
• 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 (T_g) and softening temperature (T_s). 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.

• 마이크로전자및패키징학회지
• /
• 제19권4호
• /
• pp.33-37
• /
• 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.

• 한국세라믹학회지
• /
• 제30권11호
• /
• pp.974-978
• /
• 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.

• 공업화학
• /
• 제3권3호
• /
• pp.430-439
• /
• 1992

입자무기물 충전 복합재료에 있어서 계면의 친화성과 충전재의 분산성을 향상시키기 위하여 고분자 수지로 마이크로캡슬화된 glass beads를 제조하였다. Glass beads의 마이크로 캡슐화에는 상분리법을 이용하였으며, 벽막수지로는 EMAA와 EAA를 사용하였다. 캡슐화 형성상태를 분석하기 위하여 열분석과 SEM을 이용하였다. HDPE에 캡슐화 glass beads를 10~30중량 퍼센트까지 충전시켜 HDPE/마이크로캡슐화 glass beads 복합재를 제조하고 벽막수지종류와 캡슐화 비율에 따른 인장강도, 인장탄성율 및 동역학적 성질의 변화를 측정하였다. 인장강도의 경우 캡슐화 glass beads로 충전시킨 경우 복합재의 인장강도저하가 현저하게 둔화되었으며, 인장탄성율의 경우 캡슐화 glass beads로 충전시킨 경우 30~40% 정도의 향상된 값을 나타내었다. 동역학적 물성측정에 있어서는 계면접착력과 분산성의 향상을 볼 수 있었다. 그러나 벽막수지의 종류에 따른 복합재의 물성 차이는 크지 않음을 알 수 있었다.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2005년도 춘계학술대회논문집
• /
• pp.246-249
• /
• 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.

• 한국세라믹학회지
• /
• 제35권12호
• /
• pp.1337-1342
• /
• 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.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
• /
• pp.396-399
• /
• 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.