We propose optical phase-control devices using a liquid crystal (LC) material without applying a voltage, and demonstrate a composite alignment of LC molecules on a substrate with a patterned photo-resist film, where LC molecules are partly aligned parallel and perpendicular directions divided into very small areas on the substrate. The patterned film such as randomly distributed circular areas of small diameter size is fabricated by using a photo-mask and a photolithography technique. The LC cells are prepared using the locally composite alignment substrate and a perpendicular alignment substrate. The optical phase of the transmission light through the different pattern density regions was measured. Then, it is found that the optical retardation of the higher pattern density region is larger than that of the lower one.
Optical properties in the liquid crystal (LC) microlenses are studied on molecular orientations with large and axially symmetrical electric field. The LC microlenses with a thick LC layer are also investigated by experiments and simulations of 3 dimensional finite difference method (3D-FDM). The LC microlens has a converging property with low applied voltage as well as a diverging property with high applied voltage. The dependence of converging property on D/t is investigated in the LC microlenses, where D/t is the ratio between a hole-pattern diameter D and LC thickness t, and the simulation by the 3D-FDM in terms of the molecular orientation state is successfully carried out. It is found that the lateral distribution of the LC molecular orientation in the thickness direction is not uniform and changes depending on the D/t ratio, and good converging properties can be obtained when the D/t value is around 2.