In the patterned vertical alignment ͑PVA͒ cell in which multidomains are formed from the perfect vertical alignment through an oblique field only, the formation of disclinations between liquid crystal ͑LC͒ molecules is inevitable in the presence of an electric field, which lowers transmittance and the response time. In the proposed PVA device, the pretilt angle is formed in four different directions through the polymerization of an UV curable reactive mesogen monomer at the surface. In this way, the reorientation of LC responding to an electric field is well defined, and thus the device shows reduced threshold voltage and much improved response time in all gray scales.

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The patterned vertical alignment (PVA) liquid crystal (LC) mode shows a wide viewing angle and a perfect dark state at a normal direction. However, it is inevitable to avoid the formation of disclinations and the movement of defect points during stabilization of LC's reorientation. It is due to fact that the LC directors tilt downward in different directions with collisions between them by the fringe-electric field. Consequently, the transmittance decreases and the response time gets slower. In order to overcome this barrier, the pretilt angles in four different directions are introduced on the substrates utilizing UV-curable reactive mesogen (RM) monomers. According to our studies, concentration of RM, UV curing condition, and applied voltage to the cell are critical to achieve an optimized surface-modified PVA mode which provides the well-defined reorientation of the LCs with respect to an electric field. Moreover, morphological behaviors on surface of substrate depending on curing conditions were investigated in order to confirm the existence of the stabilized polymer.

The orientational distribution in SmA, the switching behavior in SmC*, and the molecular orientation of SmC A * have been investigated by means of polarized Raman scattering due to the C–C stretching of phenyl rings in two antiferroelectric liquid crystals. The scattered intensities, I Z Z (ω) and I Y Z (ω), have been measured between crossed and parallel polars as a function of rotation angle, ω, of homogeneously aligned cells about their surface normal. The order parameters, <P 2> and <P 4>, and then the orientational distribution function in SmA were obtained by utilizing the method of information entropy. The electric-field-induced reorientation was observed in the rotation angle dependence: I Z Z (ω)∝cos 4(ω±Θ), where Θ is the tilt angle of SmC*. The characteristic rotation angle dependence obtained in SmC A * was described as I Z (ω)∝{cos 4(ω+Θ)+cos 4(ω-Θ)}/2. This result supports the molecular orientation of SmC A * so far proposed that the molecules in adjacent layers tilt in the opposite senses.