Fabrication Of Liquid Crystal Micro-lens Arrays And Its Application In Integrated Imaging

In order to naturally and vividly restore the information of the real world,3D display technology has become a hot topic of research.This paper mainly focuses on the design and fabrication of high-resistance(Hi-R)liquid crystal micro-lens arrays(LC MLAs)and improvs the performance of integral imaging(In Im)3D display through electrically controllable focal length of Hi-R LC MLAs.The contents are shown as follows:(1)Structure design of liquid crystal(LC)micro-lens.We constructed the structure of the circular-hole electrode-driven liquid crystal micro-lens by using Tech Wiz.LCD.3D software and simulated the relationship between the rotation angle of LC molecules and driving voltages.The simulation results show that the LC micro-lens have much excellentest optical properties when the rubbing orientationof polyimide(PI)layer is anti-parallel.A Multisim software was employed to construct an R-C circuit model according to the parameter of the Hi-R LC cell.The simulation results show that the working frequency of the driving signal and the square resistance of the Hi-R layer can make the surface potential of the single LC lens present the gradient distribution,which can effectively improve the photoelectric performance of the LC micro-lens.(2)Fabrication of Hi-R LC MLAs.Al electrodes with hollow-hole arrays were fabricated by magnetron sputtering and photolithography,and Al-doped Zn O(AZO)transparent film,as a Hi-R layer,was deposited on the surface of Al electrodes.The Hi-R LC cell with the cell gap of 45?m were successfully fabricated after the liquide crystal was sandwitched between the substrate with Hi-R Al-driven-electrodes and a substrate with indium-tin-oxide(ITO)common electrode.The driven-electrodes were characterized by optical microscope and step profiler.The experimental results show that the circular-hole pitch of Al-driven-electrode with thickness of 130 nm is about345.6?m,and the diameter of circular-hole is around 300?m.(3)Performance investigation of Hi-R LC MLAs.An optical test platform was built to collect interference patterns and focal radius of Hi-R LC MLAs under different parameters,and then the photoelectric performance of Hi-R LC MLAs was investigated.The experimental results show that compared with the traditional electrode-driven LC lens,Hi-R LC MLAs have uniform interefernce patterns,small focal radius and low driving voltages when the thickness of AZO high-resistance is approximately 30 nm(square resistance is 4.88×10~8?/sq).The focal lengths of Hi-R LC MLAs can be adjusted from 4.62 mm to 2.82 mm at the driving voltage(1.8Vrms-2.8 Vrms)and working frequency(90 KHz-170 KHz).(4)Construction of In Im 3D display system and analysis of imaging performance.The In Im 3D display system was constructed by Trace Pro optical software,and the influence of different LC MLAs on the reconstructed 3D images was simulated and analyzed.A prototype of In Im 3D display based on Hi-R LC MLAs was built and analyzed the reconstructed 3D images.The experimental results show that compared with the In Im 3D display based on ITO-electrode-driven LC MLAs,the In Im 3D display based on Al-electrode-driven Hi-R LC MLAs presents clear 3D images because Al-electrode-driven Hi-R LC MLAs can effectively decrease the stray light and improve the display performance of integral 3D image.In addition,electrically controllable focal lengths can realize integral 3D image display with different depths and improve the performances of In Im 3D display.