• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.1024-1027
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• 2003

The formation of cholesteric liquid crystal (CLC) film reflecting a broadbanded visible spectrum by application of a liquid crystalline coating followed by UV polymerization (photo-curing) is described. Also, the formation of patterned coatings obtained by a sequence of UV exposure steps is discussed. Such coatings play an important role in the improvement of the performance of liquid crystal displays. In order to make these CLC films, we synthesized new cholesteric liquid crystal molecules (Ch-chol) containing the active reaction site to UV light and investigated to broaden the bandwidth of these cholesteric filters based on the various UV treatments.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.879-882
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• 2008

The discotic liquid crystal in compensating film used for the viewing angle improvement of the twist nematic liquid crystal display panel is analyzed. For the optical characterization of the compensating film, we measured the polarization state of the light passing through the film as the tilt angle and the azimuth angle of the film were varied, and then we compared the measured polarization state with the calculated one. Finally we suggested the best fit configuration of the discotic liquid crystal.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.468-471
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• 2003

We firstly report liquid crystal shutter based on plastic film and its application to 3D shutter for stereoscopic displays. Plastic liquid crystal shutters have remarkable advantages compared to conventional glass liquid crystal shutters. They are thin, light and non-breakable so that very comfortable 3D shutter eye-wear can be realized using them. The concepts, optical performances and reliability test results of plastic film liquid crystal shutters are presented.

• Journal of the Optical Society of Korea
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• v.20 no.4
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• pp.510-514
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• 2016

The conventional liquid crystal displays (LCDs) have been using optically uniaxial liquid crystal (LC) medium and this often causes a significant image change at oblique viewing angles. We simulated the viewing angle properties of the biaxial nematic (N_b) phase of a bent-core liquid crystal (BLC) and compared the results with the vertically aligned (VA)- and the in-plane switching (IPS)-LCDs. The N_b phase of the BLC showed a smaller transmittance at the dark state as well as a greater contrast ratio at wide viewing angle. The viewing angle property of the N_b-mode without any compensation film was slightly superior to the IPS-mode with the compensation films eliminating the decross of the polarizers at oblique viewing angle.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.471-474
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• 2002

Three-ring types liquid crystalline compounds having fluoro and isothiocyanate substituent were synthesized and their physical and electro-optical properties were measured to evaluate the applications to active matrix VA liquid crystal displays. The tetrakis(triphenylphosphine)palladium(0) catalyzed cross coupling of aryl boronic acids with aryl halides is used to prepare trans-4'-Alkoxy-2,3-difluoro-3'-isothiocyanato-4-(4-alkylcyclohexyl}-biphenyl series. The synthesized compounds showed the nematic liquid crystalline phase and the negative dielectric anisotropy. The prepared mixtures showed faster response time and lower threshold voltage than their host mixture.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.1142-1146
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• 2004

The synthetic route and physical properties for three-ring derivatives, trans-2,3,2',3'-tetrafluoro-4-alkyl-4'-(4-alkyl-cyclohexyl)-biphenyl and 4-alkyl-cyclohexane carboxylic acid 2,3,2',3',4'-pentafluoro-biphenyl-4-yl ester are presented. They exhibit broad range nematic phases exceeding 30K and low viscosity of nematic liquid crystal mixtures containing these materials. Their viscosity is compared with that of homologues with a lateral isothiocyanate group and show large negative dielectric anisotropies. The threshold voltage $V_{th}$ was low enough to be operated at a driving voltage of 5V. Our novel LC compounds are suitable materials for the improvement of dielectric anisotropy of vertical align liquid crystal displays (VA-LDCs).

• Korean Journal of Optics and Photonics
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• v.25 no.6
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• pp.301-310
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• 2014

Recently, the fringe-field switching (FFS) mode in liquid crystal displays has been used mainly for high image quality and high-resolution liquid crystal displays (LCDs). In this review paper, the fundamental switching principle of the FFS mode, with its excellence over other LC modes in electro-optic performance, will be described. In addition, the development history, present technical issues, and future of the FFS LCD will be discussed.

• Transactions on Electrical and Electronic Materials
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• v.17 no.2
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• pp.69-78
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• 2016

Liquid crystals are important materials because of their applications in display technology and many other scientific applications. Different mixtures of liquid crystals and their doped samples have gained interest because a single liquid crystal compound cannot fulfill all the required parameters for the display application. The doping can be accomplished with dyes, polymers, or composite nanoparticles among other substance. The addition of nanoparticles can modify the physical properties of the host liquid crystal and enhances the performance of electro-optical devices. The present study is focused on investigations of possible changes in dielectric and electro optical properties of liquid crystals caused by doping with ceramic nanoparticles. Including smaller nanoparticles were found to be better candidates for use in suppressing the unwanted ion effects in liquid crystal displays.

• Proceedings of the Korean Vacuum Society Conference
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• 1993.07a
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• pp.17-17
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• 1993

• Journal of the Korean Graphic Arts Communication Society
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• v.13 no.2
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• pp.19-32
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• 1995

Liquid crystal-polymer composite(LCPC) films are promising new materials for both projection displays and vision products. LCPC films consist of a continuous liquid crystal phase embedded in a three- dimensional network of polymer matrix. The liquid crystal in these LC phases can be electrically switched giving rise to an opaque scattering off-state and a transparent, non- scattering on-state. In this work, a premixture is composed of LC, UV-curable monomer and photonitiator. LCPC films are formed by photopolymerization induced phase separation from this premixture. In conclusion, structure and electro-optical properties of LCPC films strongly depends on the selection of monomer, LC content and curing rate.