| Surface Stabilized Ferroelectric Liquid Crystal (SSFLC) devices exhibit bi-stable director configurations that can be selected via the interaction between the electric field and spontaneous polarization of FLC. However, an issue with the SSFLC technology is layer defects. In this dissertation we focus on the causes of these layer defects, and propose solutions for the case of low and high pretilt devices.;The most obvious layer defect formation, called the zig-zag defect, occurs when domains with chevrons pointing in opposite directions are interspersed. It is well known that this type of defects can be eliminated by a high pretilt. However, recently work has shown the existence of a defect free chevron C1 texture with a low pretilt. One focus of this dissertation is to consider the causes of zig-zag defect formation in low pretilt devices and to predict conditions where they will not form. Related to this, we show for the first time, that if the azimuthal anchoring energy is below a critical value, that a uniform C1 layer structure can be expected.;Even if the zig-zag defect is eliminated, some other more subtle disruptions of the otherwise uniform SmC* layer structure can be observed. We have observed that these defects often are seen first as the cell is cooled through the SmA phase during the cell preparation. A second focus of this dissertation is the understanding and control of these types of layer defects that originate in the SmA phase. Through X-ray data and microscopic observations we show that materials with layer expansion in the SmA leads to an exceptionally uniform layer structure in the SmC* phase.;This understanding will allow for many new improvements to bistable SSFLC displays, including new material design, and fast high contrast ratio displays. |
