Ultra-thin Light-guide Film For Three Dimensional Display Applications

No-glasses three-dimensional displays can enable audience to view the stereoscopic images with ease and without requiring any additional accessories. Directional backlight has become keystone of research as one of important 3D display technologys. Most of directional backlight systems are based on geometrical optics. Nano-grating directional backlight technology is based on wave optics, it can provide full-parallax multiview stereoscopic experience with less crosstalk under back lighting through waveguide. In this dissertation, the nano-grating directional backlight technology is discussed, including the theory and experiment.Firstly, the diffraction properties of nano-grating are analyzed by using rigorous coupled-wave theory, including the diffraction efficiency dependence on the grating depth, duty cycle and the incidence angle of illumination. The optimization process of parameters of the nano-grating is given. The grating parameters can be calculated by using grating equation, including the period and groove orientation. The far-field distribution for nano-grating pixel are analyzed by using FDTDThen the nano-grating directional light-guide plate is designed, it is rectangular. The light guiding unit on the surface is composed of nanometer gratings whose transmission wavelengths are 650 nm, 532 nm and 450 nm in order. The light sources are red, green, blue LED or semiconductor laser array. The parameters of the light guiding unit can be calculated according to the relationship between the coordinates of the display surface and viewing point.An ultraviolet continuously variable spatial frequency photolithography process has been discussed. The process has provided low cost fabrication of variable spatial frequency grating pixels with high efficiency. The measurement of diffraction efficiency dependence on viewing angle is demonstrated, the value is 5%. Simultaneously, the brightness is decreased by 30%. The deviation is analyzed between the measured and simulated value.Lastly, the properties of light-guide plate with nano-grating are demonstrated through experiment, it can separate many images to arbitrary viewing points. In this way, we have fabricated 4 cm×4 cm images with nine different viewing directions by using variable grating, compare with the uniform grating,it can provide better stereoscopic experience. We have also fabricated 4 cm×4 cm multiview directional light-guide plate and image photomask, it also can be provide stereoscope experience through alignment.