• Journal of Electrical Engineering and Technology
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• 제4권4호
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• pp.527-530
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• 2009

$(Ba_{0.57}Sr_{0.33}Ca_{0.10})TiO_3$(=BSCT) powders, prepared by the sol-gel method, were doped using $MnCO_3$ as the acceptor and $Dy_2O_3$ as the donor. This powder was mixed with an organic vehicle. BSCT thick films were fabricated by the screen-printing techniques on the alumina substrate. The structural and dielectric properties of BSCT thick films were investigated with variation of the $Dy_2O_3$ amount. As a result of the differential thermal analysis (DTA), the exothermic peak was observed at around $670^{\circ}C$ due to the formation of the polycrystalline perovskite phase. All the BSCT thick films showed the XRD patterns of a typical polycrystalline perovskite structure. The average grain size of BSCT thick films decreased with an increasing amount of $Dy_2O_3$. The relative dielectric constant and dielectric loss of the BSCT thick film doped $Dy_2O_3$ 0.1mol% were 4637.4 and 1.6% at 1kHz, respectively.

• 한국전기전자재료학회논문지
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• 제19권1호
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• pp.75-80
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• 2006

We have fabricated a carbon nanotube field emission display(CNT-FED) panel with a 2 inch diagonal size using a screen printing method and in-situ vacuum sealing technology. The field emission properties of CNT FED panel with square-type CNT emitters. As results, the square-characterized and compared with those of the line-type CNT emitters. As results, the square-type CNT emitters showed much larger emission current and more stable I-V characteristics. Light emission started to be occurred at an electric field of 3.5 V/${\mu}m$ corresponding to the anode-cathode voltage of 700 V. The vacuum level inside of the in-situ vacuum sealed panel was obtained with $1.4 {\times} 10^{-5}$ torr. The sealed panel showed the similar I-V characteristics with the unsealed one and the uniform light emission with very high brightness at a current density of $243 {\mu}A/ cm^2$ obtained by the electric field of 10 V/${\mu}m$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.165-166
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• 2008

$(Ba_{0.6},Sr_{0.3},Ca_{0.1})TiO_3$ powders, which were prepared by sol-gel method using a solution of Ba-acetate, Sr-acetate and Ca-acetate and Ti iso-propoxide, were mixed with organic vehicle and the BSCT thick films were fabricated by the screen-printing techniques on high purity alumina substrates. The structural and dielectirc properties were investigated for various $Pr_2O_3$ and $Y_2O_3$doping contents. As a result of thermal analysis of $(Ba_{0.6},Sr_{0.3},Ca_{0.1})TiO_3$ powders, the exothermic peak was observed at around $670^{\circ}C$ due to the formation of the polycrystalline perovskite phase. All BSCT thick films, sintered at $1420^{\circ}C$ for 2h, showed the typical XRD patterns of perovskite polycrystalline structure. The average grain size of the specimens decreased with amount of $Pr_2O_3$ and $Y_2O_3$ contents.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.167-167
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• 2008

The barium strontium calcium titanate powders were prepared by sol-gel method. Ferroelectric $(Ba_{0.54}Sr_{0.36}Ca_{0.1})TiO_3$(BSCT) thick films were fabricated by the screen-printing method on alumina substrate. And we investigated the structural and dielectric properties of BSCT thick films with the variation of sintering temperature. As a result of thermal analysis, BSCT polycrystalline perovskite phase was formed at around $660^{\circ}C$. The results of X-ray diffraction analysis were showed a cubic perovskite structure without presence of the second phase in all BSCT thick films. The average grain size and the thickness of the specimen sintered at $1450^{\circ}C$ were about 1.6 mm and 45 mm, respectively. The relative dielectric constant increased and the dielectric loss decreased with increasing the sintering temperature, the values of the BSCT thick films sintered at $1450^{\circ}C$ were 5641 and 0.4% at 1kHz, respectively.

• International Journal of Precision Engineering and Manufacturing
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• 제4권4호
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• pp.51-56
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• 2003

Generally, the build-up printed circuit board manufactured by a sequential process involving etching, plating, drilling, etc, which requires many types of equipments and long lead time. Etching process is suitable for mass production, however, it is not adequate for manufacturing a prototype in the development stage. In this study, we introduce a screen printing technology for prototyping a build-up printed circuit board. As for the material, photo/thermal curable resin and conductive paste are used for the formation of dielectric and conductor. The build-up structure is made by subsequent processes such as formation of a liquid resin thin layer, solidification by a UV/IR light, and via hole filling with a conductive paste. By use of photo curable resin, productivity is greatly enhanced compared with thermal curable resin. Finally, the basic concept and the possibility of build-up printed circuit board prototyping are proposed in comparison with the conventional process.

• 한국전기전자재료학회논문지
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• 제19권8호
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• pp.749-753
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• 2006

The $ZnGa_2O_4$ phosphor thick films were fabricated using a screen printing method on Si(100) substrates at various sintering temperatures. The XRD patterns show that the $ZnGa_2O_4$ thick films have a (311) main peak and a spinel structure with increasing sintering temperatures. The particle sizes of $ZnGa_2O_4$ phosphor were about 100 nm and the thickness of $ZnGa_2O_4$ thick film was $10{\mu}m$. The CL and PL properties of $ZnGa_2O_4$ showed main peak of 420nm and maximum intensity at the sintering temperature of $900^{\circ}C$. These results indicate that $ZnGa_2O_4$ phosphor thick films hold promise for displays such as plasma display panel and field emission display.

• 동력기계공학회지
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• 제22권1호
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• pp.64-71
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• 2018

Currently, functional patterns are formed by screen printing on stretchable films, and they are applied to wearable and stretchable devices. In this study, three types of silver paste were prepared using three polyester binders with different Tg and molecular weights in order to impart elasticity to the conductive pattern itself. Rheological properties and DSC measurements were performed for each silver paste. Then, each silver paste was screen printing and cured by an IR dryer to evaluate adhesive strength, pencil hardness, resistance and surface shape change according to strain. As a result, it was found that the silver paste using a binder with a low Tg and a high molecular weight has the smallest resistance change depending on the strain. Namely, it was found that it is most preferable to use a binder with a low Tg and a high molecular weight as the stretchable electrode.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.407-407
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• 2008

무기EL 디스플레이는 고체재료에 전계를 가했을 때 발광하는 현상을 이용한소자로서, 급속도로 발전을 거듭하고 있으나, 유전체층에 강한전계를 가하여 발광하여야 하므로 낮은 Breakdown voltage와 효율의 한계로 인하여 휘도가 낮고 풀 컬러화 디스플레이 등 의 응용에는 적용되고 있지 못하는 실정이다. 본 연구에서는 강유전체 Perovskite 구조를 가지는 ABO3 물질 중 PMN(Lead Magnesium niobate) 과 PZT (Lead Zirconate titanate) 후막을 제조하여 Inorganic EL(Electro Luminance)에 적용하고 소자의 광전특성을 평가하였다. 소자에 사용된 기판은 고온소성에 알맞은 알루미나(Al2O3)기판을 채택 하였으며, 그 위 하부전극으로는 고온소성에 따른 화학적 안정성이 우수한 Au전극을 Screen Printing 하였다. 제조 되어진 PMN후막 페이스트는 PMN(Pb(Mg1/2 Nb2/3)O3) + Glass Frit(Pb-Zn-B) + BaTiO3(99.99%) 로 합성되었으며 하부전극위에 인쇄하였다. 그 다음 PZT sol-gel을 Spin coating으로 도포 하였다. 형광체로 ZnS:Cu.Cl 을 Screen Printing을로 형성하였으며, 평탄화를 위하여 유기물 충을 Screen Printing 공정으로 성막 하였다. 상부전극으로는 DC sputter로 ITO를 증착하여 EL소자 완성 후 Spectro - Chroma meter로 소자특성을 측정하였다. 평탄화를 통한 유기물층에 변화되는 Capacitance를 Oscilloscope로 전압 전류 pulse의 변화에 따른 opto-electronic 특성을 평가하였다.

• Transactions on Electrical and Electronic Materials
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• 제8권4호
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• pp.149-152
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• 2007

[ $(Ba_{0.6}Sr_{0.3}Ca_{0.1})TiO_3$ ](BSCT) thick films doped with 0.1 mol% $MnCO_3\;and\;Yb_2O_3(0.1{\sim}0.7mol%)$ were fabricated by the screen printing method on the alumina substrates. And the structural and electrical properties as a function of $Yb_2O_3$ amount were investigated. The exothermic peak was observed at around $680^{\circ}C$ due to the formation of the poly crystalline perovskite phase. The lattice constants of the BSCT thick film doped with 0.7 mol% is 0.3994 nm. The specimen doped with 0.7 mol% $Yb_2O_3$ showed dense and uniform grains with diameters of about $4.2{\mu}m$. The average thickness of all BSCT thick films was approximately $70{\mu}m$. Relative dielectric constant and dielectric loss of the specimen doped with 0.7 mol% $Yb_2O_3$ were 2823 and 3.4%, respectively. The Curie temperature of the BSCT thick films doped with 0.1 mol% $Yb_2O_3$ was $46^{\circ}C$.

• 한국인쇄학회지
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• 제15권2호
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• pp.57-76
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• 1997

A color halftoning is the process of generating halftone images for the different color plans, for example, cyan, magenta, yellow, and black for a offset printing device. A conventional halftone technique, so called AM screening, is simple and easy to implement, but the halftoned dot patterns by using this method is not free for the moire` fringe. Moire` patterns are caused the power spectrum distribution on low spatial frequency domain. To avoid Moire` patterns, the conventional screen require the different screen angles for each color plans. Recently, Ultra-fine and 7 color printing methods are developed to expend the color gamut. In 7 color printing method must be used the halftone technique of random and blue noise characteristic to avoid Moire` fringe.