• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.6
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• pp.547-551
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• 2006

We studied liquid crystal (LC) alignment with ion beam (IB) on polyimide and electro-optical characteristics of twisted nematic (TN)-liquid crystal display (LCD) on the polyimide surface using obliquely ion beam (IB) exposure with new IB type equipment. A good uniform alignment of the nematic liquid crystal (NLC) alignment with the ion beam exposure on the polyimide surface was observed. In addition, it can be achieved the good EO properties of the ion-beam-aligned TN-LCD on polyimide surface. Also, the EO characteristics of the ion-beam-aligned TN-LCD on a polyimide (PI) surface with ion beam exposure using new type IB equipment is same or more superior than ion-beam-aligned TN-LCD on a polyimide (PI) surface with ion beam exposure using Kaufman-type Ar ion gun.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1177-1177
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• 2004

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2000.11a
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• pp.133-136
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• 2000

We investigated the improvement of viewing angle using a patterned double twisted (PDT) vertical-alignment (VA) cell mode on a homeotropic alignment layer. Good voltage-transmittance curves for negative dielectric anisotropic nematic liquid crystal (NLC) using the PDT-VA cell without a negative compensation film were obtained. The viewing angle of the PDT-VA cell without a negative compensation film was wider than that of a conventional VA cell.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.133-136
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• 2000

We investigated the improvement of viewing angle using a patterned double twisted (PDT) vertical-alignment (VA) cell mode on a homeotropic alignment layer. Good voltage-transmittance curves for negative dielectric anisotropic nematic liquid crystal (NLC) using the PDT-VA cell without a negative compensation film were obtained. The viewing angle of the PDT-VA cell without a negative compensation film was wider than that of a conventional VA cell.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.489-490
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• 2005

We studied the nematic liquid crystal (NLC) aligning capabilities using the new alignment material of the SiC (Silicon Carbide) thin film. The SiC thin film exhibits good chemical and thermal stability. The good thermal and chemical stability makes SiC an attractive candidate for electronic applications. A vertical alignment of nematic liquid crystal by ion beam exposure on the SiC thin film surface was achieved. The about $87^{\circ}$ of stable pretilt angle was achieved at the range from $30^{\circ}$ to $45^{\circ}$ of incident angle. The good LC alignment is main-tained by the ion beam alignment method on the SiC thin film surface at high annealing temperatures up to 300.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.5
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• pp.321-326
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• 2021

We fabricated BiAlO thin film by a solution process with a brush coating to be used as liquid crystal (LC) alignment layer. Solution-processed BiAlO was coated on the glass substrate by brush process. Prepared thin films were annealed at different temperatures of 80℃, 180℃, and 280℃. To verify whether the BiAlO film was formed properly, X-ray photoelectron spectroscopy analysis was performed on Bi and Al. Using a crystal rotation method by polarized optical microscopy, LC alignment state was evaluated. At the annealing temperature of 280℃, the uniform homogenous LC alignment was achieved. To reveal the mechanism of LC alignment by brush coating, field emission scanning electron microscope was used. Through this analysis, spin-coated and brush coated film surface were compared. It was revealed that physical anisotropy was induced by brush coating at a high annealing temperature. Particles were aligned in one direction along which brush coating was made, resulting in a physical anisotropy that affects a uniform LC alignment. Therefore, it was confirmed that brush coating combined with BiAlO thin film annealed at high temperature has a significant potential for LC alignment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.329-329
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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, noncontact 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 poly imide 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 poly imide surface was observed. The tilt angle of NLC on the PI surface with ion beam exposure can be measured under $1^{\circ}4 for all of irradiation angles. In addition, it can be achieved the good ED properties, and residual DC property of the ion beam aligned TN cell on polyimide surface.

• Polymer(Korea)
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• v.27 no.5
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• pp.484-492
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• 2003

How the characteristics and stability of the rubbing-induced alignment of nematic liquid crystals (LCs) relate to the interfacial characteristics of LC-polyimide has been studied. The characteristics of the LC alignment (such as the LC texture, the pretilt angle, and the anchoring energy) and their thermal stability have been investigated for 5 polyimides synthesized for this work. The work showed that the rubbed polyimide alignment layer induces the strong LC anchoring and that the characteristics and stability of LC alignment are determined by the short-ranged interactions between LC and polyimide molecules at the alignment layer surface. The increased flexibility of the polyimide accelerates thermal imidization, increases the pretilt angle, and improves the alignment stability. It also turned out that fluorination of the polyimide tends to deteriorate the alignment uniformity and stability. No distinct differences in the alignment characteristics were shown for the aromatic- and alicyclic-dianhydride polyimides.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.623-624
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• 2009

Here we report a photo polymerization-induced hybrid alignment of a nematic liquid crystal cell which can be applied for a roll to roll fabrication process. Predominant polymerization in the vicinity of UV incident front induced a diffusion of monomers toward front slide and anisotropic polymer network was formed parallel to the polarization direction of the UV light. This induced planar alignment of liquid crystals at the front slide. Simultaneously, homeotropic alignment was induced at the bottom slide as the polymers are phase-separated from a bottom slide.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.299-302
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• 2007

We propose a soft-lithographic patterning method for producing a multi-domain liquid crystal (LC) alignment. The LC alignment polyimide layers are periodically patterned in the pixel boundaries by a micromolding-in-capillaries method. In our structure, the initially homeotropic LC orientations in the pixel areas are changed to axially symmetric LC domains due to the symmetric pretilt of LC molecules on the pixel boundaries.