• Journal of Information Display
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• v.5 no.3
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• pp.14-17
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• 2004

We have developed a new type of transflective liquid crystal display (LCD) with a single cell gap and a single LC mode. In our transflective configuration, a single LC mode of a 60$^{\circ}$ twisted nematic LC was used for both transmissive and reflective applications. The measured electro-optic characteristics of our transflective LC cell agree well with numerical simulation results. Moreover, the transmittance was found to show similar behavior to the reflectance.

• Journal of Information Display
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• v.12 no.4
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• pp.191-194
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• 2011

A symmetric-viewing inverse-twisted-nematic (ITN) liquid crystal display (LCD) with alternating alignment layers was developed using a stamping-assisted rubbing (SAR) technique. A patterned layer of a fluorinated acrylate polymer was transferred onto the first rubbed vertical-alignment layer prepared on a substrate by stamping. The fluorinated acrylate polymer provided a protective layer covering the first rubbed alignment layer during the second rubbing process, which promoted the vertical alignment of the LC molecules. The LC cell in the ITN geometry with two orthogonally rubbed alignment layers showed symmetric-viewing characteristics with fourfold symmetry. The SAR technique was shown to be a mask-free alignment method of producing multidomains for symmetric-viewing LCDs.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.4
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• pp.426-431
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• 2004

We have studied the pressure-dependent liquid crystal's dynamics in a twisted nematic (TN) liquid crystal panel with thin film transistor by applying an external pressure to it. When the external pressure is applied to the panel in a dark state, the disclination lines were generated as a light leakage whereas they did not appear in a simple test cell that has only pixel and common electrodes. It was because the disclination lines were Provoked by the electric field between pixel electrode and data/gate bus line for active matrix driving. Consequently, the external pressure resulted in dynamic instability of the liquid crystal so that the disclination lines at the data/gate bus line intruded into the active area.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.390-391
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• 2007

We have studied improvement of light leakage of twisted nematic liquid crystal display (TN-LCD) in dark state using the hybrid aligned compensation film made of rod-like LC. When the voltage is applied properly to the TN-LCD, the director tilts up but LC director on the substrate don't tilts up due to surface anchoring energy of the LC cell. Accordingly, LC director from surface to middle LC of TN -LCD become hybrid state such as hybrid aligned film. Consequently, in this paper we achieve wide viewing angle performances of TN mode using developed hybrid aligned film which especially decreases light leakage at vertical direction in dark state.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.05a
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• pp.114-117
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• 2005

We have fabricated twisted nematic (TN) cell doped by carbon nanotubes (CNTs). The CNTs with a minute amount of doping do not perturb the liquid crystal orientation in the off- and on-state. The hysteresis studies of voltage-dependent transmittance and capacitance under ac and dc electric field show that the amount of residual dc, which is related to image sticking problem in liquid crystal displays, is greatly reduced due to ion trapping by CNTs.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.4
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• pp.302-306
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• 2019

We investigated a solution-derived $Y_2O_3$ film treated by ion beam (IB) irradiation as a liquid crystal (LC) alignment layer. With IB irradiation, homogeneous LC alignment was achieved irrespective of the annealing temperature. To verify the effect of IB irradiation, we conducted surface analyses such as X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). As $Y_2O_3$ is a high-k material, the electro-optical properties of the twisted nematic (TN) cells were superior to those of conventional TN cells based on a rubbed polymer, with an LC rising time of 4.1ms and falling time of 2.9ms. The IB-irradiated $Y_2O_3$ is a good alternative as an alignment layer for fast-switching TN LC displays.

• 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.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.11
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• pp.1234-1240
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• 2004

We studied on the electro-optic characteristics and dynamic stability according to an undesirably defined pretilt angle induced in high step coverage of pixel area for the Twisted Nematic (TN) / Fringe-Field Switching (FFS) mode. In case of the TN mode, LC directors twist reversely near the edges of thin-film-transistor and black matrix where the pretilt angle of the LC is not well defined. Therefore, the voltage-dependent dynamics of the LC in TN mode is unstable and shows the bad electro-optic characteristics. On the other hand, in case of the FFS mode, the LCs are twisted parallel to the bottom substrate by fringe electric field and the electro-optic characteristic is not influenced by the pretilt angle of the LC which is not well defined.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.498-501
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• 2003

We investigated response characteristics of twisted nematic (TN) cell with different nematic liquid crystals (NLCs) and cell gap d on a rubbed polyimide (PI) surface. High transmittance and fast response time of the TN cell on the rubbed PI surface were achieved by using high birefringence (${\Delta}n$) and low cell gap d. The transmittance and response time of the TN cell on the rubbed PI surface decreased with decreasing ${\Delta}nd$. The fast response time of TN cell using high birefringence with ${\Delta}nd=0.363$ on the rubbed PI surface was measured 5.1 ms.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.489-492
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• 2001

We studied a method to use a variable discrete random phase mask in 2-D binary data representation for efficient holographic data storage. The variable phase mask is realized by use of a twisted nematic liquid crystal display.