• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.141-144
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• 2000

New photo-alignment materials based on PCEMA (Poly (4-methacryloyloxylchalcone)) for liquid crystal (LC) aligning were synthesized. And the electro-optical (EO) characteristics of the photo-aligned TN-LCD were investigated. The excellent LC alignment and voltage-transmittance (V-T) characteristics for the photo-aligned TN-LCD on PCEMA surface containing more cinnamoly group can be achieved. However, the reverse tilt disclinations for the photo-aligned TN-LCD on the PCEMA surface containing more OH group were observed. Consequently, we suggest that the LC aligning capabilities can be increased by increasing of cinnamoly group on the PCEMA surfaces.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.3
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• pp.235-240
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• 2000

New photh-alignment materials based on PCEMA (poly(4-methacryloyloxylchalcone))for liquid crystal (LC) aligning were synthesized. and the electro(EO) characteristics of the photo-aligned TN-LCD were investigated. The excellent LC alignment and voltage-transmittance (V-T) characteristics for the photo-aligned TN-LCD on PCEMA surface containing more cinnamoly group can be achieved. However the reverse tilt disclinations for the photo-aligned TN-LCD on the PCEMA surface containing more OH group were observed. Consequently we suggest that the LC aligning capabilities can be increased by increasing of cinnamoly group on the PCEMA surfaces.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.766-768
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• 2004

Rubbed films of a series of poly(p-phenylene 3,6-bis(4-(n-alkyloxy)phenyloxy)pyromellitimide)s (Cn-PMDA-PDA PIs), which are well-defined brush PIs composed of two aromatic-aliphatic bristles per repeat unit of a fully rodlike backbone, were investigated in detail using atomic force microscopy (AFM), optical retardation analysis and linearly polarized infrared (IR) spectroscopy in order to elucidate their surface morphology and molecular orientation. The liquid crystal (LC) alignment behavior and the anchoring energy of LC molecules on the rubbed films were also determined.

• 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 Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.04a
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• pp.44-44
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• 2008

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, non contact alignment has been investigated. Ion beam induced alignment method, which provides controllability, nonstop process, and high resolution display. In this study, we investigated liquid crystal (LC) alignment with ion beam (IB) that non contact alignment technique on polyimide and electro-optical characteristics of twisted nematic (TN)-liquid crystal display (LCD) on the polyimide under various ion beam angles. In this experiment, Polyimide layer was coated on glass by spin-coating and Voltage-transmittance(VT) and response time characteristics of the TN cell were measured by a LCD evaluation system. The good characteristics of the nematic liquid crystal (NLC) alignment with the ion beam exposure polyimide surface was observed. The tilt angle of NLC on the PI surface with ion beam exposure can be measured under $1^{\circ}$ for all of irradiation angles. In addition, it can be achieved the good EO properties, and residual DC property of the ion beam aligned TN cell on polyimide surface.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.7
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• pp.635-640
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• 2005

In this paper, we have improved a novel high tilted optically compensated bend (OCB) (HTOCB) mode by using high tilt angle that was generated by the unique baking condition on the homeotropic alignment layer. The high tilt angle of liquid crystal (LC) was generated by new alignment process that tilt angle changed homeotropic state to homeogenous state using Hot-plate equipment; we obtained about $40\~50^{\circ}$ tilt angle with negative and positive dielectric anisotropy on the homeotropic polyimide (PI), and then LC tilt angle decreased as increasing baking temperature and time. At last, we obtained about $10^{\circ}$ with positive type NLC $({\Delta}n>0)$. Also, the LC tilt angle of positive type NLC $({\Delta}n>0)$ decreased as increasing rubbing strength at the same baking temperature and time. The novel LC operating mode (HTOCB) that used the high tilt angle by the new alignment method was improved. The response time of the novel HTOCB cell was faster than that of conventional OCB cell. We suggest that the developed the novel HTOCB cell using control of tilt angle on the homeotropic surface is a promising technique for the achievement of a fast response time and a high contrast ratio.

• 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.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.04a
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• pp.23-26
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• 2004

We studied the nematic liquid crystal (NLC) aligning capabilities using the new alignment material of a Carbon Nitride (NDLC) thin film. NDLC thin film exhibits high electrical resistivity and thermal conductivity that are similar to the properties shown by diamond-like carbon (DLC) thin films. The diamond-like properties and nondiamond-like bonding make NDLC an attractive candidate for applications. A high pretilt angle of about $9.9^{\circ}$ by ion beam (IB) exposure on the NDLC thin film surface was measured. A good LC alignment is achieved by the IB alignment method on the NDLC thin film surface at annealing temperature of $200^{\circ}C$. The alignment defect of the NLC was observed above annealing temperature of $250^{\circ}C$. Consequently, the high pretilt angle and the good LC alignment by the IB alignment method on the NDLC thin film surface can be achieved.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.208-208
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• 2009

We used Brewster's Law to examine the mechanism of liquid crystal (LC) alignment on an organic insulation layer when subjected to ion-beam irradiation. Brewster's Law implies that the maximum rate polarized ray on a slanted insulation layers on the substrate and it illustrates the dependence of polarization and themechanical structure on the ion beam irradiation process. The pretilt angle of nematic LCs on the organic insulation surface was about $1.13^{\circ}$ for an ion beam exposure of $45^{\circ}$ for 1 minute at 1800eV. This shows the dependence of LC alignment on the polarization ratio in a slanted organic insulation layer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.04a
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• pp.45-46
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• 2008

The conventional biased vertical alignment (BVA) mode has several advantages such as rubbing- and protrusion-free, wide-viewing angle and stable LC dynamics against external pressure. However manufacturing process of BVA mode is difficult task because the pixel and bias electrode signal are different in each frame. To solve this problem, we investigated the pattern free vertical alignment (PFVA) by using the UV-curable reactive mesogen (RM), in which the LC molecules were made to be pre-tilted. Eventually transmittance and response time in PFVA mode were found to be improved as compared to BVA mode.