The Study Of Tabletop Autostereoscopic 3D Display On Directional Backlight

With the popularization of 3D movies in recent years,the demand of display technology that provides depth information and is with compact format is increasing.In this paper,a tabletop autostereoscopic 3D display based on directional-backlight is presented.Compared with the traditional autostereoscopic 3D display device which is based on geometrical optics(cylindrical lens,Parallax Barrier),it is able to form an annular viewing window and provide a periscopic display effect.When compared with the tabletop autostereoscopic 3D display devices equipped with rotating screens,the proposed device has a much smaller and lighter system setup.In this paper,we discretize the circular light field to compress the data which is based on the principle of directional-backlight.Furthermore,we separate the phase information from the amplitude information of the sampled light field.The multi-view image coding is refreshable by LCD(liquid crystal display)panel.The phase information of the sampled light field can be reconstructed by using pixelated nano-gratings.By matching the phase information and the amplitude information,the sampled light field can be reconstructed to from a circular viewing window above the display.In this paper,the modulation mechanism of the pixelated nano-grating is studied in detail.The parameters involved in the light regulating in the grating are analyzed systematically,and the light field distribution after the pixelated nano-grating is calculated and studied with the finite difference time domain method(FDTD).Then a home-made dual beam interference lithography system is used to fabricate the nano-grating structureswith continuous variable frequency and angle.In this paper,we further analyzed the image distortion problem which may occur in the process of the light field reconstruction.We discussed the methods to reduce the distortion of image pickup and reconstruction.In order to prove the feasibility of the proposed tabletop 3D display technology,we choose three different directions with a separation of 90 degree between each,and made an autostereoscopic 3D display prototype which can reconstruct the virtual object in 16 views distributed in the front,back and side.