• Transactions on Electrical and Electronic Materials
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• v.6 no.6
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• pp.272-275
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• 2005

We studied the control of pretilt angles for homeotropic aligned nematic liquid crystal (NLC) on SiOx thin film surface by $45^{\circ}$ evaporation method with electron beam system. The uniform vertical LC alignment on. the SiOx thin film surfaces with electron beam evaporation was achieved. It is considered that the LC alignment on SiOx thin film by $45^{\circ}$ electron beam evaporation is attributed to elastic interaction between LC molecules and micro-grooves at the SiOx thin film surface created by evaporation. The pretilt angles of about $3.5^{\circ}$ in aligned NLC on SiOx thin film surfaces by electron beam evaporation of $45^{\circ}$ were measured. Consequently, the high pretilt angles of the NLC on the SiOx thin film by $45^{\circ}$ oblique electron beam evaporation method can be achieved.

• Transactions on Electrical and Electronic Materials
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• v.7 no.6
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• pp.293-296
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• 2006

We studied homeotropic alignment effect for a nematic liquid crystal (NLC) on the $SiO_{x}$ thin film irradiated by the new ion beam method. $SiO_{x}$ thin films were deposited by plasma enhanced chemical vapor deposition (PECVD) and were treated by the DuoPIGatron ion source. A uniform liquid crystal alignment effect was achieved over 2100 eV ion beam energy. Tilt angle were about $90^{\circ}$ and were not affected by various ion beam energy.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.05a
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• pp.51-53
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• 2005

$Zn_{1-x}Cd_xO$ thin films were grown on (0001) sapphire substrates by pulsed laser deposition. The energy bandgap of $Zn_{1-x}Cd_xO$ films decreases withincreasing Cd content. An increase of Cd content also leads to the emission broadening and degraded crystallinity. The absorption edge and ultraviolet emission peak shift to lower energy from 3.357 eV to 3.295 eV and 3.338 eV to 3.157 eV, respectively, with increasing Cd content from 0.3% to 3%. The Stokes' shift between the absorption and emission indicates the increase of localization of exciton with Cd content.

• Transactions on Electrical and Electronic Materials
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• v.9 no.5
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• pp.202-205
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• 2008

We have studied the liquid crystal (LC) orientation behavior on the organic hybrid overcoat layer with ion beam irradiation. Excellent LC alignments of the nematic liquid crystal (NLC) on the ion beam irradiated organic hybrid overcoat layers were observed in various intensities above 600 eV. Pretilt angles of the NLC on the organic hybrid overcoat layers for all ion beam energy intensities were observed from 0.2 to 0.5 degrees. Also, we used the atomic force microscopy (AFM) images for measuring the roughness of the organic hybrid overcoat layers with ion beam irradiation before and after. The surface of organic hybrid overcoat layers was leveled off by the ion beam irradiation. Finally, a good LC alignment thermal stability on the organic hybrid overcoat layer with ion beam irradiation can be achieved.

• Transactions on Electrical and Electronic Materials
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• v.9 no.5
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• pp.198-201
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• 2008

The electro-optical (EO) characteristics of the one-side rubbing twisted nematic (TN) - liquid crystal display (LCD) on the polyimide (PI) surface with one-side ion beam (IB) irradiation were successfully studied. The good LC alignment for the one-side rubbing TN-LCD on the PI surface with one-side IB irradiation was observed. The suitable transmittance-voltage curves for the one-side rubbing TN-LCD on the PI surface with one-side IB irradiation were measured. Also, the good response time characteristics of the one-side rubbing TN-LCD on the PI surface with one-side IB irradiation were measured. The fast response time can be achieved for the one-side rubbing TN-LCD on the PI surface with one-side IB irradiation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.371-371
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• 2007

In this study, liquid crystal (LC) aligning capabilities for vertical alignment on the $CeO_x$ thin film by thermal evaporation method were investigated. Also, the control of pretilt angles and thermal stabilities of the NLC treated on $CeO_x$ thin film were investgated. The uniform LC alignment on the $CeO_x$ thin film surfaces and good thermal stabilities with thermal evaporation can be achieved. It is considerated that the LC alignment on the $CeO_x$ thin film by thermal evaporation is attributed to elastic interaction between LC molecules and micro-grooves at the $CeO_x$ thin film surface created by evaporation. In addition, it can be achieved the good electro-optical (EO) properties of the VA-LCD on $CeO_x$ thin film layer with oblique thermal evaporation.

• Proceedings of the KIEE Conference
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• 2007.10c
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• pp.250-252
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• 2007

본 논문에서는 Multi-stage Electro-magnetic Launcher(EML)를 개발함에 있어, Photo Sensor Switching System을 구성하여 Reluctance type의 2-Stage Coilgun을 설계, 제작하였다. 이를 위해, 솔레노이드 코일의 최적 aspect ratio와 발사체의 size를 F.E.M. 해석을 통해 결정하였고, 탄속측정기를 제작하여 실험을 통해 각 stage의 최적 시정수를 결정하였다.

• Journal of Electrical Engineering and Technology
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• v.13 no.1
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• pp.393-399
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• 2018

An electrostatic boundary-value problem of a dielectric-wedge-backed, double-slotted conducting wedge is investigated to analyze an asymmetric coplanar waveguide with an infinite dielectric thickness using the Mellin transform and a mode-matching method. Our theoretical solution based on eigenfunction expansion and residue calculus is a rigorous and fast-convergent series form. Numerical computations are conducted to evaluate the potential field, capacitance, and characteristic impedance for various structures of the asymmetric coplanar waveguide. The computed results show good agreement with the simulated results.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1340-1343
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• 2007

We have simultaneously fabricated LTPS TFTs and integrated photodiodes on the same glass substrates without any additional LTPS process. The structure of an integrated photodiode is a lateral p-i-n diode with a gate. The performances of a photodiode were improved at a negative gate voltage.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2004.07a
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• pp.363-363
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• 2004