• 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.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.422-425
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• 2006

Recently, studies on orientation of carbon nanotubes (CNTs) dispersed in nematic liquid crystal (LC) and CNTs effects on electro-optic characteristics of the LC device have been performed. In this paper, we summarize interaction nature between CNT and LC, local distortion of the LC director field by motion of CNTs, and effects on electro-optic performances of LC device.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.290-292
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• 2007

A twisted nematic type liquid crystal electro-optic modulator (TN-LC modulator) was developed. The modulator used single polarizer and the reflection on-off ratio was maximized by optimization of twist angle and retardation of liquid crystal cell. The TNLC modulator shows better sensitivity and response time than conventional liquid crystal modulator.

• Journal of Information Display
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• v.12 no.1
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• pp.11-15
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• 2011

An inverse-twisted-nematic (ITN) transflective (TRF) liquid crystal (LC) display, where two imprinted optical films (IOFs) with surface microstructures are embedded was developed. One of the IOFs serves as an in-cell patterned retarder with multioptic axes, and the other behaves as a viewing-angle enhancement film. In the presence of an applied voltage, the surface microstructures on the IOFs provide the spontaneous twist of the LC from a vertically aligned state to a $90^{\circ}$ twisted-nematic (TN) state in the transmissive part, and to a $45^{\circ}$ TN state in the reflective part. The developed ITN TRF LC display exhibits high transmission and reflectance, fast response, and wide-viewing characteristics, along with achromaticity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.440-441
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• 2006

We have studied the narrow viewing angle liquie crystal displays (LCDs) using a hybrid aligned nematic liquid crystal (LC) cell driven by a fringe field. The device using a LC with positive dielectric anisotropy has a relatively low transmittance. This paper describes how to improve light efficiency by optimizing electrode structure. The results show that the device exhibits a high transmittance of 90%, low driving voltage and narrow viewing angle less than $20^{\circ}$ along horizontal direction which is highly effective for private display application.

• Korean Journal of Optics and Photonics
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• v.21 no.2
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• pp.69-73
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• 2010

We propose a method to enhance the response time of a twisted nematic liquid crystal (TN-LC) cell using an anisotropic polymer. Polymer networks are formed by the phase separation between a LC and a UV-curable polymer. A TN-LC cell is exposed to UV light after the mixture of LC and anisotropic polymer is injected into the TN-LC cell. As a result, turn-off time of a TN-LC cell can be decreased remarkably without any loss of the transmittance. The turn-off time of a TN-LC cell with pure LC was 16 ms, but those of polymer networked TN-LC cells were 12, 11, and 9 ms when the concentration of the polymer was 3, 5, and 10 wt%, respectively. Moreover, by virtue of the polymer network, the backflow effect and the delay time generated during the turn-off process disappeared.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.284-287
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• 2017

This paper introduces liquid crystal (LC) alignment and its electro-optical properties in the LC cells with silver nanowire (AgNW) networks. The AgNW network was used as an electrode of LC cell as a substitute for an indium-tin-oxide (ITO) film. LC alignment characteristics in the LC cell using AgNW networks, which have two different sheet resistances of $60{\Omega}/m^2$ and $80{\Omega}/m^2$, were observed. The LC alignment characteristics including pretilt angle, LC alignment state, and thermal stability are similar irrespective of sheet resistance of AgNW network. However, twisted-nematic (TN)-LC cell normally operated when using AgNW network with sheet resistance of $80{\Omega}/m^2$. Electrooptical properties of TN-LC cell exhibited competitive performance compared to those of TN-LC cell based on conventional ITO electrode, which allow new approaches to replace conventional ITO electrode in display technology.

• Electrical & Electronic Materials
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• v.10 no.5
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• pp.461-466
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• 1997

In this paper, we developed the new non-rubbing liquid crystal (LC) alignment techniques in the cell with slanted non-polarized ultraviolet (UV) light irradiation on polyimide (PI) film. It is shown that the uniform alignment for nematic (N) LC is obtained by using slanted non-polarized UV light irradiation on PI surface. We successfully obtained that the pretilt angle of NLC is generated about 3.3 degree in the cell with slanted non-polarized UV light irradiation with 70 degree on PI surface, for the first time. It is considered that the pretilt angle generation in NLC is attributed to interaction between the LC molecular and the PI, which is broken the polymer by slanted non-polarized UV irradiation. Therefore, we concluded that the uniform LC alignment is attributed to anisotropic dispersion force due to photo depolymerization with slanted non-polarized UV light irradiation on PI surface.

• 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 the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.5
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• pp.530-535
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• 2004

We have studied 90$^{\circ}$ twisted nematic mode switching by fringe electric field(F-TN mode) using a liquid crystal (LC) with negative dielectric anisotropy. In the device, two polarizers are parallel each other, electrodes exist only on bottom substrate, and one of rubbing direction is coincident with polarizer axis. Therefore, the cell shows a black state before a voltage is applied. With a bias voltage generating fringe-electric field, the LC twists perpendicular to fringe electric field such that the LCs are almost homogeneously aligned except near the bottom surface since the negative type of the LC is used. Consequently, the new device exhibits much wider viewing angle than that of the conventional TN mode due to in-plane switching and relatively high transmittance since the LC director above whole electrode area aligns parallel to the polarizer axis.