Fabrication Of Compound Microlens Array And Imaging Research

As the development of the optical technology, microlens arrays attract researchers’ favor gradually. In recent years, the methods of fabricating microlens array are also emerging in endlessly, which are many mature fabrication methods, for example, laser ablation, photolithography, heat reflow, electrowetting, electrohydrodynamics, and so on. Because the structures of microlens arrays have inherent property of the optical lens, such as m icrominiaturization, easy to integrate and tunable focal length, the microlens arrays are widely used in various fields. Most of fabricated microlens arrays are monolayer structure now, so we proposed and fabricated a kinds of compound microlens array, and analyzed the optical performance of the compound microlens array. The main research contents of this paper are as follows:A taper microlens array was fabricated by using water-assisted femtosecond laser direct writing technology in glass materials. Through improving the traditional laser direct writing technology, the microstructures in glass can be fabricated by the water-assisted femtosecond laser direct writing technology, and this fabrication method can enhance the fabrication efficiency. During the fabrication process, micro-cylindrical structures array was fabricated in glass firstly, the size of micro-cylindrical structure and the distribution of the microlenses can be controlled through precisely controlling 3D precision stage. Subsequently, the micro-cylindrical array should be heated in tube furnace, then the internal surface of micro-cavity will become much smoother under the glass transfer temperature and the surface tension, at the same time, the micro-cylindrical structures turn into tapered array structures. Finally the optical performance of the taper microlens array was tested. The experimental results demonstrated that the taper array structures have good imaging ability and splitting ability.Two novel polymer compound microlenses arrays w ith two focal imaging properties were proposed and fabricated, especially, the concave polymer compound microlens array with virtual focus imaging ability and real focus imaging ability. The multilayer polymer compound microlens array can be fabricated on a silica glass substrate which with the hydrophobic material Teflon by micro-droplets technology. During the fabrication process, the concave-convex and convex-convex two types compound microlens array can be formed under the different solidified way. The influence between the curing temperature, curing time and diameter of microlens were investigated. The compound microlens array was modeled and detected in theory and experiment, The experimental results demonstrated that compound microlens arrays have an excellent secondary imaging ability and focal ability, the results of experiment fit very well with the theoretical simulation.A simple and low-cost method for fabricating embedded compound microlens array structures was proposed, the focal length of the compound microlens arrays which were fabricated by this method can be controlled and selectable according to the curvature radius of embedded microlens structures. The compound microlens array structures were simulated through the optical design software. A set of microlens structures with eight groups different curvature radius were set and simulated by ray tracing. Subsequently, a SU-8 photoresist microlens array on a silica glass substrate with the hydrophobic material Teflon was fabricated by the micro-droplet inkjet technology. The embedded compound microlens array was fabricated through the pattern transfer, SU-8 micro-droplet imbedding, and PDMS packaging. The optical performance of the compound microlens array was detected, the experimental results d emonstrated that the compound microlens arrays have a good imaging ability and focusing ability.