P‐25: An Accurate Spectral Method for Measuring Twist Angle of Twisted Cells with Rubbed and Grooved Surfaces

Abstract

Accurate optical method for measuring twist angle in TN LC cells is presented. Deviation of the measured values for different orientations of the cell and polarizes have been analyzed. The method allows to determine twist angle with high accuracy for cells with rubbed surfaces as well as for cells where at least one surface is corrugated.

Parameters on the LC alignment of organosilicon compound films

“…Measuring the azimuthal anchoring energy was carried out using the method of a spectral analysis suggested in Ref. 16.…”

“…The cell was rotated at the angle of 22.5°i n plane normal to the passing light. It was shown 16 that the inaccuracy of the azimuthal anchoring energy determination for the smooth and profiled surfaces would be mini-mum, if the wavelength λ c at which all three spectra crossed at a point was selected. The LC-cell transmission of light at the wavelength λ c was determined by the formula: (11) where φ LC is the LC twist angle, and β P-A is the angle between the polarizer and the analyzer.…”

Liquid Crystal Alignment Layer With Controllable Anchoring Energies

“…Azimuthal anchoring energy can be calculated by using the following formula: (1) where is the measured twist angle of the sample cell, is the twist elastic constant of LC, is the measured cell gap.…”

“…The anchoring energy of the polyimide is determined by the chemistry of the polyimide material and is generally in the range of 10 to 10 J/m . Different methods of measuring the azimuthal [1], [2] and polar anchoring energy have been reported previously [3]- [5].…”

P‐115: New Photoalignment Material: Azimuthal Anchoring Energy Decreases at Very High Photo‐Induced Order Parameters

“…The arrangement of exposure polarization directions and area patterns was the next that the LC cell has 9 areas with different exposure doses: same dose at top and bottom substrate of each area, but the photoalignment directions at top and bottom substrates were set perpendicular to each for 90 degree twist nematic (TN) cell (Fig.2) The azimuthal anchoring energy was measured automatically on polarization microscope [10] for every exposure area of the patterned photoaligned TN LC cell using torque balanced method. The azimuthal anchoring energy dependence of ATA-2 layer on the exposure dose is presented on Figure 3 -black curve.…”