• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.400-400
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• 2007

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 exposured polyimide surface was observed. In addition, it can be achieved the good EO properties, and residual DC property of the ion beam aligned TN cell on polyimide surface.

• 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.30 no.4
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• pp.362-366
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• 2006

It was found by polarized FTIR spectroscopic studies that pentacene molecules are arranged with their molecular axes perpendicular to the substrate surface when pentacene films are deposited on a polyimide alignment layer. The ring plane in a pentacene molecule is arranged parallel to the rubbing direction of the polyimide alignment film while no specific arrangement of vertically deposited pentacene molecules was found for the film without rubbing. The pentacene band at $1296cm^{-1}$ which has a transition dipole moment parallel to the ring plane is much stronger in a polarized IR spectrum of parallel to the rubbing direction, whereas the band at $908cm^{-1}$ whose transition dipole align normal to the ring plane shows much stronger intensity in a spectrum of perpendicular to the rubbing direction. These findings indicate that orientation of polyimide chains affects the arrangement of pentacene molecules when they are deposited on a polyimide alignment film.

• Journal of Electrical Engineering and Technology
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• v.8 no.6
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• pp.1457-1461
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• 2013

The effect of liquid crystal (LC) alignment on a homeotropic polyimide (PI) surface induced by ion beam (IB) irradiation and rubbing process was studied. LC alignment was not affected by IB irradiation with an exposure time of 10 s, and an IB irradiation with an exposure time of 60 s more effectively oriented the LCs on the PI layer than the rubbing process. It was assumed that the LC alignment depended on the C-O bonds created from the C=O bonds on the PI surface broken by IB irradiation after an exposure time of 60 s, which resulted in a strong surface energy that transformed the homeotropic LC alignment to homogeneous states.

• Journal of the Korean Vacuum Society
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• v.12 no.S1
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• pp.107-112
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• 2003

The alignment effect of liquid crystals on Polyimide surfaces bombarded by a low energy argon ion beam and the effect of pretilt angle on viewing characteristics of an LCD cell are discussed. The unidirectional out-of-plane liquid crystal tilt angle is varied with various ion beam irradiation conditions, such as the energy of the incident ions, the angle of incidence and exposure time. As low pretilt angle is profitable for wider viewing property, LCD cell with ion beam modified Polyimide layer show wider viewing characteristics.

• Polymer(Korea)
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• v.36 no.2
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• pp.145-148
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• 2012

The effects of the linearly polarized UV (LPUV) irradiation and thermal treatment of a photo-degradable polyimide (CBDA-ODA) alignment layer (AL) on its AL properties, liquid crystal (LC) alignment, and LCD characteristics have been investigated. The best quality of LC photo-alignment have been induced by the LPUV-irradiation with much (about 5~10 times) less dosage than that generating the maximum anisotropy of the AL. A thermal treatment of the LPUV-irradiated AL has effectively removed the undesirable, low-M.W. fragments of the AL generated during the photo-decomposition and increased the stability of the AL, which has resulted in improvement of the LC alignment and the LCD property.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.328-329
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• 2005

Inorganic alignment layer (IAL) was deposited on an indium-tin-oxide (ITO) by using reactive sputtering deposition method. After deposited, IAL was irradiated by $Ar^+$ ion beam (IB) for liquid crystal (LC) alignment. IAL treated by various conditions such as IB energy, IB incident angle, and IB irradiation time had excellent alignment property and electro-optical property the same as that of PI. We investigated into the stability of ion beam treated IAL after a lapse of long time. However IAL irradiated IB did not occur degradation of electro-optical property. The results implied that IAL irradiated IB was adopted as LC alignment layer instead of rubbed polyimide.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.337-340
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• 2001

The control of high pretilt angle for nematic liquid crystal (NLC) with negative dielectric anisotropy on the rubbed blending polyimide (homeotropic and homogeneous alignment) surface were studied. High NLC pretilt angle generated on the blending polyimide (homeotropic polyimide and SE-7492 surface was measured and the NLC pretilt angle increases with blending ratio and rubbing strength. However, the NLC pretilt angle generated on the blending polyimide (homeotropic polyimide and SE-150 surface was not varied. The high pretilt angle the NLC using blending polyimide surface can be achieved.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1719-1722
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• 2006

We proposed a soft-lithographic method for aligning a liquid crystal (LC) in patterned azimuthal orientations. It is demonstrated that a thermoplastic polystyrene layer is patterned from a thermally stable polyimide layer via pressure-assisted capillary force lithography, which provides multidirectional LC alignment condition simply followed by a unidirectional rubbing process.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.513-514
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• 2008

The potential of non-rubbing technology for applying to display devices was demonstrated by irradiating a high density argon ion beam (IB) on a polyimide (PI) as a liquid crystal alignment layer. The superior electro-optical characteristics were obtained, compared to rubbed PI, Although the low pretilt angle was created on the IB irradiated PI.