Control of the pretilt angle for liquid crystal alignment using novel electrospray deposition methods with two capillaries

The electrospray deposition (ESD) method is an established film-forming technique. To control the pretilt angle on films, we developed two novel ESD methods for spraying two kinds of solutions containing alignment materials. One method is a simultaneous spraying method, while the other is a time-divided spraying method. When we used the simultaneous-spraying ESD method, we observed numerous fine liquid crystal (LC) domains with a diameter of approximately 10 mu m in the LC cell. These LC domains were substantially smaller than those of LCs fabricated using the conventional ESD method. However, the pretilt angle could not be controlled over a wide range because multiple parameters could not be simultaneously controlled to achieve a stable spray. Using the time-division ESD method, we controlled the pretilt angle over a wide range from 5 degrees to 40 degrees, with tiny domains. As a demonstration, we fabricated a 270 degrees super-twisted nematic mode cell using this method.