Measurement Of Anchoring Energy Research Articles

40.3: Effect of Birefringent Alignment Layer on Azimuthal Anchoring Energy Measurement

Birefringent alignment layer contributes to the optics of the liquid crystal cell, which is significant for optical method of azimuthal anchoring energy measurement. We obtained analytical equation to compute the corrected value of liquid crystal twist angle subject to alignment layer retardation. The data on azimuthal anchoring energy measurements of AtA‐2 and AtA‐0042 azo‐dye photoalignment materials are obtained: above >10−4J/m2 within the wide range of exposure doses 0.04 – 5.12 J/cm2.

Polar anchoring energy measurement of photoaligned nematic liquid crystal on nanodimensional chalcogenide glass films

The polar anchoring energy of nematic liquid crystals on nanodimensional films of chalcogenide glasses irradiated with linearly polarized visible light is measured using the optical retardation at high electric field method. It is found that the polar anchoring energy is increasing with irradiation time and comparable to that reported using other UV photoalignment polymers. Together with the fact that this is a solid transparent photoalignment layer, can be deposted in large area and on curved surfaces, photoconductive, and can be patterned, the hybrid liquid crystal devices have a great potential in displays and other photonic applications.

Polar anchoring energy measurement of vertically aligned liquid-crystal cells

An electric-field method is developed for measuring the polar anchoring energy of vertically aligned nematic liquid-crystal cells. Both theoretical analyses and confirming experimental results are presented. Vertically aligned liquid-crystal cells with buffed polyimide alignment layers are used to investigate the measurement techniques. Based on the voltage-dependent transmittance of the liquid-crystal cells, a linear fitting can be obtained, leading to a precise determination of the anchoring energy. If some specific liquid-crystal material parameters are known, measuring of the cell capacitance is not necessary.

P-126: Polar Anchoring Energy Measurement of Vertically Aligned Liquid Crystal Cells

A simple high electric field method is developed for measuring the polar anchoring strength of a vertically aligned nematic liquid crystal cell. Both theoretical analyses and confirming experimental results are presented. Buffed polyimide vertically aligned liquid crystal cells are used as examples.

Nematic Film Under Electric Field: Total Internal Reflection, Surface Tilt Angle and Anchoring Energy

In this paper, we first analyze an existing anchoring energy measurement technique in terms of accuracy and surface tilt angle value as an electric field is applied to the nematic cell initially planarly aligned. We thus perform a simulation of the film behavior using a pure elastic model and derive from it a possible new method for polar anchoring coefficient measurement, based on the surface tilt angle dependence on the applied voltage. We propose an experimental setup to perform this measurement. The reported preliminary experiment (5CB nematic film aligned using a polyimid layer) shows on one hand the feasibility of the measurement and in an other hand that - in that specific case - the pure elastic model is too restrictive and extra surface phenomena have to be accounted for.

P‐79: Influence of Multiple Beam Interference on Azimuthal Anchoring Energy Measurement Using Liquid Crystals with Different Chiralities

AbstractThe influence of multiple beam interference on azimuthal anchoring energy measurement using liquid crystals with different chiralities was investigated using 4 * 4 matrix method. It is shown that there are suitable measurement conditions to minimize the influence of multiple beam interference, improving the anchoring energy measurement. Calculation results and the measurement method are discussed.

An Improved Azimuthal Anchoring Energy Measurement Method Using Liquid Crystals with Different Chiralities

An improved method for measuring the azimuthal anchoring energy of liquid crystals has been developed. Without knowing the easy axes of the cells precisely, it is possible to measure their anchoring energy precisely, using the same liquid crystals but with different chiralities for the divided cells. The principles and measurements are discussed.