• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1126-1129
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• 2006

Here we developed a conductive ink which contains silver nanoparticles from which the electrodes for organic thin film transistor were directly patterned by ink-jet printing. To fabricate a coplanar type OTFT, solution processable semiconducting oligomer, ${\alpha},{\omega}-dihexylquaterthiophene$ (DH4T) was drop-cast onto between the ink-jet printed silver electrodes and I-V characteristics were measured.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.463-466
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• 2007

It is a revolutionary technology of making color filters by ink-jet printing. The difficult reason of this method is that it is a merger technology of many fields. There must be perfect orientation systems, designed capacity and production equipment of automatically controlled printing head. Moreover, accurate ink with modification is also needed.

• Korean Journal of Materials Research
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• v.17 no.9
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• pp.453-457
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• 2007

Interest in use of ink-jet printing for pattern-on-demand fabrication of metal interconnects without complicated and wasteful etching process has been on rapid increase. However, ink-jet printing is a wet process and needs an additional thermal treatment such as an annealing process. Since a metal ink is a suspension containing metal nanoparticles and organic capping molecules to prevent aggregation of them, the microstructure of an ink-jet printed metal interconnect 'as dried' can be characterized as a stack of loosely packed nanoparticles. Therefore, during being treated thermally, an inkjet-printed interconnect is likely to evolve a characteristic microstructure, different from that of the conventionally vacuum-deposited metal films. Microstructure characteristics can significantly affect the corresponding electrical and mechanical properties. The characteristics of change in microstructure and electrical resistivity of inkjet-printed silver (Ag) films when annealed isothermally at a temperature between 170 and $240^{\circ}C$ were analyzed. The change in electrical resistivity was described using the first-order exponential decay kinetics. The corresponding activation energy of 0.44 eV was explained in terms of a thermally-activated mechanism, i.e., migration of point defects such as vacancy-oxygen pairs, rather than microstructure evolution such as grain growth or change in porosity.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.25 no.1
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• pp.20-26
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• 2015

Ceramic ink-jet printing technology in art tiles, decorated tablewares and other porcelain products has many advantages of fast and precision printing of various images with high efficiency and low cost. For the application to ink-jet printing, ceramic ink requires a stable dispersibility with nano-sized pigments. In this paper, characteristics of pink-red aqueous ceramic ink for ink-jet printing was demonstrated. $CaCr_{0.1}Sn_{0.8}SiO_5$ pigment was synthesized using solid state reaction and deagglomerated using attrition milling. The aqueous ceramic ink contains 10 wt% of the obtained $CaCr_{0.1}Sn_{0.8}SiO_5$ nanopigment with 0.4 wt% of sodium dodecyl sulfate (SDS) as a dispersion agent. Viscosity of $CaCr_{0.1}Sn_{0.8}SiO_5$ aqueous ceramic ink was adjusted using 0.18 wt% of polyvinyl alcohol (PVA) for a suitable jetting from the nozzle. The prepared pink-red ceramic ink showed a good jetting property with formation of a single sphere-shaped droplet after $180{\mu}s$ without a tail and satellite droplet.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.175-176
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• 2006

• Journal of the Korean Society for Precision Engineering
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• v.32 no.9
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• pp.787-792
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• 2015

Recently, 3D printing technology is a hot issue in various industrial fields. According to the user's application, it allows for the free form fabrication method to be utilized in a wide range. The powder based fusion technique is one of the 3D printing methods. When using this method it is possible to apply the various binder jetting techniques such as piezo, thermal bubble jet, dispenser and so on. In this paper, a multi thermal bubble ink jet was integrated for jetting of powder binding material and developing a power fused 3D printing system. For high quality 3D printing parts, it needs an analysis and evaluation of the behavior of the thermal bubble ink jet head. In the experiment, a correlation between jetting binder quantity and layer thickness of powder was investigated, and a 3D part model was fabricated, which was used by measuring the scale factor.

• Proceedings of the KIEE Conference
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• 2007.11a
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• pp.100-101
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• 2007

Polymer thick film capacitors were successfully fabricated by using ink-jet printing and screen printing technology. First, a bottom electrode was patterned by ink-jet printing of a nano-sized silver ink. Next, a dielectric layer was formed by the screen printing, then a top electrode was pattern by ink-jet printing of a nano-sized silver ink. The printed area of the dielectric layers were changed into $2{\times}2m^2$and $4{\times}2m^2$, and also the area of the electrodes were patterned with $1{\times}1mm^2$ and $1{\times}3mm^2$. The thickness of the printed dielectric layer was ranged from 1.1 to $1.4{\mu}m$. The analysis of capacitances verified that the capacitances was proportional to the area of the printed electrode. The capacitances of the fabricated capacitors resulted in one third of the calculated capacitances.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.5 s.248
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• pp.413-421
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• 2006

The bubble dynamics induced by direct laser heating is experimentally analyzed as a first step to assess the technical feasibility of laser-based ink-jet technology. To understand the interaction between laser light and ink, the absorption spectrum is measured for various ink colors and concentrations. The hydrodynamics of laser-generated bubbles is examined by the laser-flash photography. When an Ar ion laser pulse (wavelength 488 nm) with an output power up to 600 mW is incident on the ink solution through a transparent window, a hemispherical bubble with a diameter up to ${\sim}100{\mu}m$ can be formed with a lifetime in a few tens of microsecond depending on the laser power and the focal-spot size. Parametric study has been performed to reveal the effect of laser pulse width, output power, ink concentration, and color on the bubble dynamics. The results show that the bubble generated by a laser pulse is largely similar to that produced by a thin-film heater. Consequently, the present work demonstrates the feasibility of developing a laser-actuated droplet generation mechanism for applications in ink-jet print heads. Furthermore, the results of this work indicate that the droplet generation frequency is likely to be further increased by optimizing the process parameters.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.157-162
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• 2003

Piezoelectric ink jet offers a promising combination of productivity, reliability and uniformity that are appropriate for jetting organic electronic materials. Spectra is manufacturing a printhead specifically for display manufacturing. This printhead contains a robust material set and is intended to allow calibration of individual nozzles to meet uniformity requirements of+/-2% for display manufacture.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.8 s.185
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• pp.15-21
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• 2006