Research On Adaptive Liquid Crystal Microlens

Liquid crystal lens (LCL) is one kind of the adaptive lens, based on controlling driving voltage to achieve the gradient refractive index distribution of liquid crystal. Compared with conventional solid lens, liquid crystal lens has the advantages such as mechanical control devices, thin, tunable focal length and so on. Liquid crystal microlens array (<1mm) has an important application background in adaptive imaging, 3D display, optical tweezers and portable optical devices. Large aperture (>1mm) LCL is widely used in mobile phones, personal projectors and other optoelectronic devices.When the aperture is small, the circular hole liquid crystal lens (CHLCL) has a good characteristic in focus. However with the increase of the aperture, the characteristic becomes poor. So the modal control liquid crystal lens (MCLCL) was researched and the modal control liquid crystal lens with central electrode (CMCLCL) was proposed.This paper analyzes the potential distribution and molecules director distribution of MCLCL and CMCLCL with different parameters by theoretical simulations. The results show that, when the applied voltage is fixed, the potential distribution and the refractive index distribution of MCLCL depend on times of three parameters, that is, the voltage frequency, sheet resistance of high resistance film and capacitance of LCL. When the product of the three parameters of different MCLCLs were same, the potential distribution of the surface hole and the refractive index distribution were same too. Applying a suitable voltage to the central electrode of MCLCL, the potential distribution and phase distribution were closer to the ideal parabolic distribution, the character of focus would be better too. The radius of the lens was larger, this effect was more pronounced.Then introduced the preparation process of LCL, to prepare the LCLs with different apertures and different structures is investigated. The test system for LCLs is set up to test their interference ring, focal length and other optical properties. This paper prepared a tunable focus liquid crystal microlens array with the aperture of 229.2um and the minimum focal length of 1.194mm which is applied in 3D system and conversion of 2D/3D. The tunable focus CHLCLs and MCLCLs with the aperture of 2mm-4mm and good character of imaging are also prepared. Through the result we found that for the CHLCL and MCLCL of same aperture, MCLCL had better character of imaging and lower voltage amplitude for optimal imaging.To research fast response LCL, this paper studied blue phase liquid crystal (BPLC) preliminarily. On the basis of study of the basic principles of the BPLC device, three different BPLCs were prepared and used to prepare BPLC lens (BPLCL). Then tested the BPLCL’s ability of focus and pointed that BPLCL’s utility was reduced by its high drive voltage.