• 한국전산유체공학회:학술대회논문집
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• 2008.03a
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• pp.340-346
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• 2008

A level-set method is developed for computation of drop motions in various engineering applications. Compared with the volume-of-fluid method based on a non-smooth volume-fraction function, the LS method can calculate an interface curvature more accurately by using a smooth distance function. Also, it is straightforward to implement for two-phase flows in complex geometries unlike the VOF method requiring much more complicated geometric calculations. The LS method is applied to simulation of inkjet process, thin film pattering and droplet collisions.

• 한국전산유체공학회:학술대회논문집
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• 2008.10a
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• pp.340-346
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• 2008

A level-set method is developed for computation of drop motions in various engineering applications. Compared with the volume-of-fluid method based on a non-smooth volume-fraction function, the LS method can calculate an interface curvature more accurately by using a smooth distance function. Also, it is straightforward to implement for two-phase flows in complex geometries unlike the VOF method requiring much more complicated geometric calculations. The LS method is applied to simulation of inkjet process, thin film pattering and droplet collisions.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.926-929
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• 2007

A significant progress has been made in the characterization of zinc oxide (ZnO) semiconductor as a new semiconductor layer instead of amorphous Si semiconductor used in thin film transistor due to its high electron mobility at low deposition temperature which is quite suitable for flexible display and OLED devices. The wet pattering of ZnO is another important issue with regard to mass production of ZnO thin film transistor device. However, the wet behavior of ZnO thin film in aqueous wet etching solutions conventionally used un TFT industry has not been reported yet, in this work, wet corrosion behavior of RF magnetron sputtered ZnO thin film in various wet solutions such as phosphoric and nitric acid solutions was studied using by electrochemical analysis. The effects of deposition parameters such as RF power and oxygen partial pressure on corrosion rate are also examined.

• Laser Solutions
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• v.12 no.4
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• pp.1-5
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• 2009

Conventional patterning based on wet-process for multi-layered film is a relatively complex and costly process though it is a necessary step for fabrication of TFT-LCD module. Recently, a direct pattering by laser has been studied because it is low cost and simple process compared to the wet process. In this work, the selective removal process of multi-layered film (polyimide/indium tin oxide/glass) is studied by modeling the thermal and mechanical behavior for multi-layered structure. Especially, the effects of thickness of polyimide layer are examined.

• Laser Solutions
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• v.13 no.1
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• pp.11-15
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• 2010

Indium tin oxide (ITO) provides high electrical conductivity and transparency in the visible and near IR (infrared) wavelengths. Thus, it is widely used as a transparent electrode for the fabrication of liquid crystal displays (LCDs) and organic light emitting diode displays (OLRDs), photovoltaic devices, and other optical applications. Lasers have been used for removing coating on polymer substrate for flexible display and electronic industry. In selective removal of ITO layer, laser wavelength, pulse energy, scan speed, and the repetition rate of pulses determine conditions, which are efficient for removal of ITO coating without affecting properties of the polymer substrate. ITO coating removal with a laser is more environmentally friendly than other conventional etching methods. In this paper, pattering of ITO film from polymer substrates is described. The Yb:KGW femtosecond laser processing system with a pulse duration of 250fs, a wavelength of 1030nm and a repetition rate of 100kHz was used for removing ITO coating in air. We can remove the ITO coating using a scanner system with various pulse energies and scan speeds. We observed that the amount of debris is minimal through an optical and a confocal microscope, and femtosecond laser pulses with 1030nm wavelength are effective to remove ITO coating without the polymer substrate ablation.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1154-1157
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• 2006

Organic thin-film transistors (OTFTs) based on a semiconducting polymer have been fabricated using an organic patterning methodology. Laser assisted lift-off (LALO) technique, ablating selectively the hydrophobic layer by an excimer laser, was used for producing a semiconducting polymer channel in the OTFT with high resolution. The selective wettability of a semiconducting polymer, poly (9-9-dioctylfluorene-co-bithiophene) (F8T2), dissolved in a polar solvent was found to define precisely the pattering resolution of the active channel. It is demonstrated that in the F8T2 TFTs fabricated using the LALO technique and is applicable for the larger area display.

• Particle and aerosol research
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• v.13 no.3
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• pp.111-118
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• 2017

Electrohydrodynamic (EHD) printing with the aid of strong electric fields can generate and pattern droplets that are smaller than droplets by other printing technologies. Conventional EHD printing has created two-dimensional (2D) patterns by moving its nozzle or a substrate in X and Y directions. In this study, we aimed to develop an EHD system that can create 2D patterns using a multielectrode array (MEA) without moving a nozzle or substrate. In particular, printing ink mixtures of biodegradable polymers and model dyes was patterned on a thin film made of another biodegradable polymer. Without movement of a nozzle and substrate, stable 2D patterning of minimum $6{\mu}m$ size over a range of about 1 mm away from the nozzle position was achieved by MEA control only. We also demonstrated the possibility of denser 2D pattering of the ink mixtures by moving a target substrate relative to MEA position.