• Journal of the Optical Society of Korea
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• v.15 no.3
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• pp.289-292
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• 2011

Reactive mesogen (RM) is an organic liquid crystal molecule that can be self-aligned to have an optic axis of birefringence when coated over a polyimide alignment film. A free-standing optical wave-plate film consisting of RM and low-loss optical polymers was fabricated in this work, and the film was inserted across the polymer waveguide to form an integrated optical polarization converter. For convenient evaluation of the polarization converters, a waveguide polarizer and analyzer were fabricated in series. The polarization conversion efficiency was measured to be 25 dB for the wavelength range from 1520 to 1580 nm. The wave plate exhibited a temperature-dependent retardation of $4.5^{\circ}$ for a temperature change from 25 to $100^{\circ}C$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.339-340
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• 2008

The Conventional PVA (patterned vertical alignment) mode showed characteristics of 8-domain using T-T type or C-C type. But these methods have disadvantages such as decreasing aspect ratio and transmittance. In order to resolve these problems, in this paper we have studied a new 8-domain method which is partially using the UV curable reactive mesogen (RM) that is a role in surface stabilization. The characteristic of off-axis color shift is decreased because the part of surface stabilized area is compensated to other area in a pixel. Consequently, the device shows improved color shift by 8-domain.

• Journal of the Optical Society of Korea
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• v.19 no.3
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• pp.265-271
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• 2015

We propose a reactive mesogen (RM) lens array to obtain good focusing behavior along with a short focal plane, where the focusing behavior is switchable according to the polarization state of incident light. Polarization-dependent focusing behavior is obtained using a planoconvex RM microlens array on a planoconcave isotropic lens template. Even though the sagitta of our RM lens is high, to obtain the short focal length, the RM layer can be aligned well by introducing a top-down alignment effect, using a nanogrooved template. The optical noise due to the $moir{\acute{e}}$ effect generated by the nanogrooves on the surface of the planoconvex RM layer can be removed simply by overcoating a thin RM layer, which is self-aligned by the geometric surface effect, without an additional alignment process. We demonstrate a hexagonal-packed RM lens array that has a very high fill factor and symmetric phase profile, for an ideal lens.

• Bulletin of the Korean Chemical Society
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• v.11 no.3
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• pp.209-214
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• 1990

A series of compounds consisting of 4'-oxybenzylidene-4-n-butylaniline, a mesogen, and a p-substituted phenoxyterephthaloyl structure a non-mesogen, interconnected through a central hexamethylene spacer were synthesized and their thermal behavior and liquid crystallinity were studied. p-Substituents included in this study are H, Cl, CN, $NO_2,\;n-C_4H_9O$ and phenyl groups. The compounds having phenyl and $n-C_4H_9O$ substituents are enantiotropic and form smectic-A(SA) and nematic (N) phases. The compound with $NO_2$ substituent is monotropic and forms only a nematic phase on heating the solid, whereas it forms nematic as well as $S_A$ phases on cooling the isotropic liquid. The rest compounds were found to be non-liquid crystalline. This is in great contrast to the fact that the monomesogenic model compound 4'-n-hexyloxybenzylidine-4-n-butylaniline forms $S_B,\;S_C,\;S_A$ and N phases enantiotropically.

• Proceedings of the Korean Fiber Society Conference
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• 1987.06b
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• pp.40-40
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• 1987

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.187-187
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• 2009

The PVA(patterned vertical alignment) mode has a excellent dark state at normal direction. but they has a disclination area at divided domain region at voltage on state. so this disclination make a slow response time and decrease transmittance. To overcome this problem, we research about polymer stabilized vertical alignment (PS-VA) method which was using the UV curable reactive mesogen. According to our research, UV exposure condition which was UV dosage condition effected to rising time and decay time and also threshold voltage.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.188-188
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• 2009

We have studied the optically compensated splay (OCS) mode using reactive mesogen (RM) monomer to reduce critical voltage, setting voltage and phase transition time from initial bend to splay state. Through the polymerization of UV curable RM monomer, the high pretilt angle from vertical alignment was formed at the surfaces. In this way, orientation of the LC with OCS mode can be achieved without setting voltage and improved electric characteristic.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.04a
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• pp.45-46
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• 2008

The conventional biased vertical alignment (BVA) mode has several advantages such as rubbing- and protrusion-free, wide-viewing angle and stable LC dynamics against external pressure. However manufacturing process of BVA mode is difficult task because the pixel and bias electrode signal are different in each frame. To solve this problem, we investigated the pattern free vertical alignment (PFVA) by using the UV-curable reactive mesogen (RM), in which the LC molecules were made to be pre-tilted. Eventually transmittance and response time in PFVA mode were found to be improved as compared to BVA mode.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.90-90
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• 2006

Mesogen-Jacketed Liquid Crystalline Polymers, MJLCPs, are polymers with mesogenic side groups directly attached to main-chains without using flexible connecting spacers and are able to form liquid crystalline structures. Later work on structure-property of the polymers revealed that the side groups are not necessarily mesogenic for the polymers to form a mesophase so long as that the side groups are directly attached to the backbones and the side groups are large enough. Because of its inherent chain stiffness and that the monomers of MJLCPs are readily polymerizable by "living" free radical polymerizations, MJLCP offered a unique handy tool for making block copolymers. In addition, MJLCP offered also new opportunities for novel functional materials.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.242-243
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• 2006

In this work, we report the synthesis and characterization of azomethineester polymers that consist of banana-shaped mesogen in their backbone. Two parts of the key structure of five-ring bent-core mesogen were modified by connecting different angle of central unit (Ar), and introducing lateral substituent into the outer ring (X). The synthetic details includes (1) placing the dioxydodecamethylene unit as a flexible spacer, (2) possessing 2,3- or 2,7-naphthylene, or 1,2-phenylene connection on the central unit, and (3) introducing fluorine or chlorine substituent (X = F or Cl) into the outer phenylene unit.