Preparation And Application Of Special-shaped Microlens Array With TiO₂ Organic-inorganic Hybrid Films By Nanoimprint Technology

As an important research achievement of micro optics in recent years,microlens array has been widely focused,and applying in the fields of biomedicine,luminescent materials,and 3D imaging.This paper combines direct contact lithography technology,thermal reflow technology with ultraviolet nanoimprinting technology,which not only solves the disadvantages of traditional lithography thermal reflow technology,such as the difficulty of controlling the lens vector and the non-reusable lens array,but also microlens arrays are prepared on different substrate materials,resulting in different applications.Moreover,this paper also uses the sol-gel method combined with spin-coating technology to fabricate ultraviolet-sensitive titanium dioxide based organic-inorganic hybrid films,and special-shaped microlens array has better performance than the ordinary microlens array.First,direct contact photolithography technique is used to fabricate photoresist column array on a silicon wafer by spin coating,photolithography,and development,and then thermal reflow is performed to thermally expand the photoresist to form a lens structure.Next,using spin-coating technology to prepare titanium dioxide-based organic-inorganic film with appropriate thickness and the PDMS soft template is transferred the array pattern on the silicon wafer.After fully pressing and contacting,the film is placed under ultraviolet lamp for exposure.When the film is fully cured,the PDMS soft template is removed from the film.The microlens array is placed in an oven and heated to remove excess solvent,making the performance of the microlens array more excellent.Through the analysis of the optical transmittance,surface morphology,refractive index thickness and transmission mode of the film,the relevant optical properties of the film are obtained;Through the analysis of FIIR,XPS and thermogravimetric,the relevant element composition of the film is obtained;Through the analysis of SEM and optical microscope test and analysis to obtain the integrity and uniformity of the microlens array;Through the analysis of the lens profile by a probe profiler to obtain the actual parameters and transfer accuracy of the lens;Building an optical imagingsystem through the optical path of the optical microscope to analyze different shapes focusing and imaging performance of the lens;Finally,the obtained microlens array is applied to the OLED,and the improvement of the current efficiency and luminous efficiency of the microlens array is analyzed.After various characterization and analysis of the films and lens,it can be found that the films have good ultraviolet light sensitivity,high transmittance and low roughness,which fully meets the standards for preparing micro-optical devices based on it;The microlens array prepared based on it has good morphology,smooth surface,and good focusing imaging characteristics;it can be obtained from the comparison of special-shaped lenses,whether the hexagonal microlens array is in its own optical focusing imaging performance or in The improvement of OLED luminous efficiency is superior to that of ordinary circular arrays.