• 한국정보통신학회논문지
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• 제9권8호
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• pp.1793-1798
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• 2005

액정 디스플레이 소자의 디렉터 내에서 결점을 모델링 할 수 있는 fast Q-텐서법을 이용하여 불균일한 표면에서 발생할 수 있는 결점의 발생과 움직임에 대한 모델링을 하였다. 결점을 모델링하기 위하여 $1{\mu}m$ 단차의 전극을 가진 수직배향셀을 이용하였다. 모델링을 통하여 단차에서 발생하는 액정 디렉터 내에서의 결점의 발생과 결점선을 확인할 수 있었으며 이러한 결과는 실험을 통하여 확인하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.507-510
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• 2000

Alignment effects for nematic liquid crystal (NLC) using an in-situ photo-alignment method with obliquely polarized UV exposure on a polyirnide (PI) surface for homeotropic alignment were studied. The high pretilt angle in NLC can be measured by obliquely W exposure of $30^{\circ}$ on the PI surface for 10~20 min. The pretilt angle of NLC generated using the in-situ photo-alignment was higher than that of a conventional photo-alignment method.

• 한국전기전자재료학회논문지
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• 제13권7호
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• pp.625-629
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• 2000

We synthesized a new copoly (PM4Ch-ChMA) copoly(poly(4-methacryloyloxy) chalcone-cholesteryl methacrylate) having chalconyl and cholesteryl moiety for homeotropic liquid crystal(LC) alignment. Pretilt angles of nematic(N) LC generated by linearly polarized UV exposure on the copolymer surfaces were investigated. Good thermal stabilities of the synthesized copolymer were obtained by TGA (Thermogravimetric Analysis) measurement. Pretilt angles of the NLC decreased with increasing UV exposure time on the copolymer surfaces. We consider that the pretilt angle of the NLC is attributed to increased chalcone by increased UV exposure time. High pretilt angle of the NLC is attributed to increased chalcone by increased UV exposure time. High pretilt angle of 81$^{\circ}$was observed after the UV exposure for 3 min.

• International journal of advanced smart convergence
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• 제13권2호
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• pp.103-109
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• 2024

A nonlinear numerical analysis of orientation and velocity fields of the full Ericksen-Leslie theory for a nematic liquid crystal under shear flow is given. We obtained for the first time the three-dimensional orientation and two component velocity profiles evolutions for both in- and out-of-shear plane orientation anchorings. Complex evolution routes to steady state were found even for shear aligning nematic. As the Ericksen number increases monotonic evolution of velocity and orientation shifts towards multi-region nucleating director rotation growth with complex secondary flow generations. We found that contrary to the in-shear-plane anchorings like homeotropic or parallel anchorings, binormal anchoring gives rise to substantial non-planar three-dimensional orientation with nonzero secondary flow.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.831-833
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• 2004

A novel transflective-type LC mode with good display performance has been developed In order to drive both transmissive and reflective modes simultaneously without any modulation of gamma in a single-gap structure, we have introduced a new design concept in the reflective region, where the capacitance is separated into liquid crystal($C_{LC}$} and organic layer($C_{OL}$), playing a key role as a voltage divider in our cap-divided VA-mode. With this cap-divided method having both merits of simplifying process and good legibility, we have achieved good optical characteristics such as high contrast ratio and wide viewing angle in a single-gap homeotropic panel design.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.419-422
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• 2002

We have studied dielectric properties in the smectic phases of 4-(6-ethoxy-1-trifluoromethyl-hexyloxycarbonyl)-phenyl-4-Nonyloxybiphenyl-4-carboxylat ( TFMEOHPNBC ) having fluorine attached to one of its benzene rings. Homogeneous and homeotropic 1.5 and 5${\mu}m$ thick test cells were prepared to analyze molecular dynamic property. We measured capacitance as a function of temperature in the frequency range between 20 Hz and 100 kHz by using HP4284A LCR meter. We observed that the homogeneous cell has high dielectric constant causing dipole moment in smectic $C^{\ast}$ phase, but we can see the dipole moments are canceled out in antiferroelectric phase. It is found that there are two kind of the relaxation director fluctuation below 100 kHz. The first is ionic or space charge contribution below 10 Hz, and the second is Goldstone mode near 1-2 kHz. We will discuss molecular dynamics in smectic phase from extra information such as x-ray and electrooptic data.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.378-378
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• 2007

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

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 춘계학술대회 논문집 디스플레이 광소자 분야
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• pp.62-65
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• 2005

We studied the nematic liquid crystal (NLC) alignment capability by the Ultraviolet (UV) alignment method on a-C:H thin-films, and investigated electro-optical performances of the UV aligned twisted nematic (TN)-liquid crystal display (LCD) with the UV exposure on a-C:H thin film surface. A good LC alignment by UV irradiation on a-C:H thin-film surfaces was achieved. Monodomain alignment of the UV aligned TN-LCD can be observed. The good electro-optical (EO) characteristics of the UV aligned TN-LCD was observed with oblique UV exposure on the a-C:H thin film surface for 1min.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 춘계학술대회 논문집 디스플레이 광소자 분야
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• pp.189-192
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• 2005

We have investigated the EO characteristics generation of pretilt angle for a nematic liquid crystal (NLC) alignment with photoalignment method on three kinds of photopolymer surfaces using polymer substrates. The LC homogeneous alignment were observed on the PMI3CA (N-(phenyl)maleimide with 3-carbon chain cinnamoyl group) and PMIF (N-(phenyl)maleimide including fluoro cinnamoyl group). However, the homeotropic alignment on the PMI5CA(N-(phenyl)maleimide with 5-carbon chain cinnamoyl group) was obtained. Also, EO characteristics of the flexible photoaligned TN-LCD using PMIF surface are better than that of the flexible TN-LCD using PMI3CA surface. Also, the stable EO performances of flexible photoaligned VA-LCD using the PMI5CA surface was observed.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.338-338
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• 2009

To date, rubbing has been widely used to align LC molecules uniformly. Although rubbing can be simple, it has fundamental problems such as the generation of defects by dust and static electricity, and difficulty in achieving a uniform LC alignment on a large substrate. Therefore, noncontact alignment has been investigated. Ion beam induced alignment method, which provides controllability, nonstop process, and high resolution display. We investigated the high pretilt angle effects on electro-optical properties of ion beam (IB)-irradiated liquid crystal cells. on a blended polymer surface. High pretilt angle of liquid crystals IB-irradiated on a blended polymer surface including such as 5% and 10% of homeotropic polymer contents can' be achieved. The threshold voltages of IB-irradiated twisted nematic (TN) cells on a blended polymer surface decrease with increasing the pretilt angle. Also, the rising time of IB-irradiated TN cells decreases with increasing the pretilt angle. However the decay time of IB-irradiated TN cells increases with increasing the pretilt angle. Consequently, the electro-optical properties of IB-irradiated TN cells depend strongly on the pretilt angle in a blended polymer surface.