Optimization of alignment quality of ferroelectric liquid crystals by controlling anchoring energy

Abstract

Photoalignment allows precise control of anchoring energy, which enables the optimization of the alignment quality of ferroelectric liquid crystal (FLC) devices. Thus, the accurate measurement of the anchoring energy coefficient of the alignment layer in the FLC regime is critical. However, the methods proposed to date have several limitations and are not useful for FLC cells with a helical structure. In this paper, a method based on the evaluation of the optical relaxation time is proposed. The method is valid for both helical and helix-free FLC cells. The optimal anchoring energy to achieve the best alignment quality of FLCs is also investigated.

Fast switchable ferroelectric liquid crystal gratings with two electro-optical modes

“…The experimental errors and alignment quality of the cell can be attributed to this small discrepancy that can be further optimized for better results. 27 Ideally the DE screen_±1 and DE 1 should be the same, however, from experimental results, there is a slightly difference between them, which can fit the theoretical calculation very well with DE screen_±1 = 99.5% DE ±1 . It is due to the deviations associated with the cone angle δ of FLCs.…”

“…More details can be found in Ref. 27. However at the smaller field, these torques play a noticeable role in particularly for the arrangement with asymmetric boundary condition i.e.…”

Electro-Optical Modulation in Planar Aligned Ferroelectric Liquid Crystals with Subwavelength Helix Pitch

“…1, b, c), since in this case the ITO-electrode in each pixel of the matrix should be continuous rather than striped [12,13]. However, the optical axis PA, which sweeps in XZ plane (Fig.…”

Reverse bistable effect in ferroelectric liquid crystal devices with ultra-fast switching at low driving voltage

“…Traditionally, the anchoring energy is mainly dependent on the alignment mechanism and material without an effective and accurate approach to be adjusted. Until recently, a novel technique was reported to precisely control the anchoring energy by varying the alignment layer's photo-irradiation dosage, which paves the way for the investigation of the alignment layer's influence on the FLC bistability [13].…”

“…Symmetric boundary condition of FLC cell is assumed to be satisfied, d 0 and ε 0 are denoted as the thickness and the dielectric permittivity of alignment layers, respectively. Considering the voltage holding property of the photo-aligned layer SD1 satisfies the industrial standard, the drift current of the impurity ion migration can be neglected [13,17]. A driving voltage of V 0 is applied uniformly to the whole multilayer structure through the conductive ITO layers.…”