Angle Controllable Blue-phase Liquid Crystal Display

Viewing angle controllable liquid crystal display recently is a focus in research on liquid crystal display because it can show the wide viewing angle for sharing conventional information and show the narrow viewing angle for protecting personal or confidential information. Blue phase liquid crystal display(BPLCD) is regard as the next-generate display because of its very wide viewing angle and fast response speed. In this thesis, the viewing angle controllable blue phase liquid crystal display is obtained.In the first chapter, the development of viewing angle corresponding to the development of LCD display is concluded. The viewing angles of TN, IPS and VA display mode are simulated and the development is discussed. Then, few viewing angle controllable liquid crystal displays are simulated and the advantages and disadvantages of these VAC-LCDs are summarized.In the second chapter, a viewing angle controllable blue phase liquid crystal display is proposed. The low contrast in the normal direction and bad viewing angle in some special directions, which is the main problem for the viewing angle controllable methods, are solved. In wide viewing angle display mode, the proposed viewing angle controllable BPLCD has a same wide viewing angle compared with conventional BPLCD. In narrow viewing angle display mode, the viewing angle changes continuously and uniformly from very wide viewing angle to narrow viewing angle when the top common electrode is applied by variable bias voltages, in the same time, the contrast ratio in normal direction can keep above 1000. More important, the similar electrical optic curves for wide and narrow viewing angle display are obtained. The effect of permittivity of the insulation layer which is between the liquid crystal and pixel electrodes is researched, the results show that the insulation layer with high permittivity can obviously reduce the operating voltage.In the third chapter, a low voltage and continuous viewing angle controllable blue phase liquid crystal display is proposed. The proposed double-penetrating in-plane switching BPLCD with two common electrodes in the top and bottom substrates can reduce the operating voltage to less than 10 V, and the viewing angle controllable and high contrast ratio characteristics can be kept.In the fourth chapter, the biaxial compensation film for the BPLCD is analyzed under the visible light spectrum. In order to improve the viewing angle of the traditional biaxialfilm compensated BPLCD, a wide-band biaxial film is proposed. Using the wide-band biaxial film, the BPLCD almost has the same viewing angle and contrast ratio in full color display comparing with in single wavelength. And taking advantage of the proposed wide-band biaxial film, the viewing angle of the proposed continuous viewing angle controllable BP-LCD and the low operating voltage and continuous viewing angle controllable BPLCD in the full color display are recalculated.