Cell gap-dependent transmittance characteristic in a fringe field-driven homogeneously aligned liquid crystal cell with positive dielectric anisotropy

Transmittance characteristic in a homogeneously aligned liquid crystal (LC) cell driven by a fringe-electric field is investigated as a function of cell gap using the LC with positive dielectric anisotropy. In this device, the fringe-electric field drives the LCs to rotate so that the dielectric torque is electrode-positional dependent, which results in electrode-position dependency in the LC's rotating angle. As the cell gap decreases to 2 μm, more LCs are affected by surface anchoring, and the LCs above the center of electrodes, in which the LCs are twisted by elastic force between neighboring molecules, are less twisted compared to the 4 μm cell. Consequently, when the cell gap decreases from 4 to 2 μm, the transmittance also decreases even though the cell retardation value remains the same