• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1619-1621
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• 2007

Novel optical measurement systems and improved cell configurations for measuring of azimuthal anchoring energies were developed. The difference between the mechanical rubbing direction and the optical easy axis that caused errors in the previous azimuthal anchoring energy measurement was compensated. In addition, the measurement accuracy of the twist angle and therefore the azimuthal anchoring energy was greatly enhanced. As a result, we were able to obtain valid azimuthal anchoring energy values for different alignment layers.

• Journal of Information Display
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• v.9 no.1
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• pp.14-19
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• 2008

We demonstrated the capillary force lithography (CFL) method for controlling the azimuthal anchoring energy of a liquid crystal (LC) alignment layer. When a thermoplastic polymer film is heated to over the glass transition temperature, the melted polymer is filled into the mold structure by the capillary action and the aspect ratio of the pattern is determined by the dewetting time of the CFL process. Here, the proposed method showed that the azimuthal anchoring energy of the LC alignment layer could be simply controlled by the surface relief patterns which were determined by the dewetting times during the CFL patterning.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.664-667
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• 2009

We would like to show a measuring technique of azimuthal anchoring energy of the nematic liquid crystals. The electro-optical setup of liquid crystal cell, crossed polarizers and magnetic field was assumed. The planar or hybrid alignment cells were prepared. The director in the light entering substrate and the polarization of light was adjusted into parallel to the magnetic field. The director orientation of exit substrate and analyser maintained perpendicular to the magnetic field. As the magnetic field strength is increased, the director deviates from the easy axis and rotates to the field direction. We obtained an equation calculating the change of transmission with the field and measured experimentally the transmission. By comparing the calculating and experimental data, we obtained the azimuthal anchoring strength.

• Journal of Information Display
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• v.4 no.1
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• pp.1-8
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• 2003

Recent progress in both low pretilt and high pretilt defect free C1 surface stabilized ferroelectric liquid crystal (SSFLC) devices is reviewed. First, by numerical calculation to investigate the balance between surface azimuthal anchoring energy and bulk elastic energy within the confined chevron layer geometry of C1 and C2, it is possible to achieve a zigzag free C1 state by low azimuthal anchoring alignment with a low pretilt angle. The critical azimuthal anchoring coefficient for defect free C1 state is calculated. Its relationship with elastic constant, chevron angle as well as surface topography effect are also discussed. Second, using $5^{\circ}$ oblique SiO deposition alignment method a defect free, large memory angle, high contrast ratio and bistable C1 SSFLC display, which has potential for electronic paper applications has also been developed. The electrooptical properties and bistability of this device have been investigated. Various aspects of defect control are also discussed.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1711-1714
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• 2006

Anchoring energy of liquid crystals on solid substrates is a key parameter in liquid crystal technology. A nonperturbative method of its measurement by dynamic light scattering on thermal orientational fluctuations is presented, The ratio of the zenithal and azimuthal anchoring coefficients is shown to be equal to the ratio of the orientational elastic constants.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.948-950
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• 2009

A few organosilicon compounds (OC) - both cyclic and linear siloxanes with different structure of the substituents - have been synthesized. Properties of the LC anchoring on OC films have been measured. The OC investigated provide the homogeneous planar alignment with LC tilt angle in the range from $0.7^{\circ}$ to $1.9^{\circ}$. An increase of the microrelief depth results in a small increase of the tilt angle. The azimuthal anchoring is better for the films of the OC without molecular microrelief or the OC comprising polar groups.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.531-533
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• 2007

A new method is developed for the measurement of twist angles of LC molecules in an LC panel with angular resolution of 0.01degree, which allows measurement of LC panels with small twist angles. The method is based on the analysis of the change in polarization state of a light beam as it passes through the LC panel in test is rotated in-plane. Compared to other traditional method, including the analysis of transmittance change, our method is more sensitive and more precise. This method allows accurate determination of anchoring energy and close analysis of the rubbing process in the fabrication of IPS mode LC panels.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.619-621
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• 2003

We have presented in the paper preliminary results on physical characteristic parameters of a photopolymer LPPF 301 CP. The weak azimuthal anchoring energy (${\sim}5.0{\times}10^{-6}J/m^2$) of a photopolymer was measured by using a simple optical method. High pretilt up to $30^{\circ}$ has been achieved in the photoaligned cell by irradiating an obliquely incident UV light.

• Journal of Information Display
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• v.7 no.1
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• pp.12-18
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• 2006

We investigated the horizontal alignment properties such as surface morphology, pretilt angle, and polar and azimuthal anchoring energy of organic alignment material-coated surface treated by ion beam. In this investigation the energy and incident angle of ion beam were changed. We also fabricated an in-plane switching (IPS) cell by ion beam alignment. The results showed similar voltage-transmittance characteristics to those of a rubbed cell and better dark state.

• Journal of the Korean Applied Science and Technology
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• v.16 no.1
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• pp.15-20
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• 1999

Photo-crosslinkable polyimide(PI) which contains CF3 moiety was synthesized. Polarized UV light transformed ketone group of PI to hydroxyl group, which was confirmed by IR and UV-visible spectroscopy. We investigated the dichroic UV-absorption before and after photo-reaction with linearly polarized light. In particular we have attempted to clarify the relationship between the anisotropy of surface region and surface azimuthal anchoring energy and knew that the anchoring energy of photo-alignment PI is comparable with that of mechanical rubbing.