Fabrication Of Microlens Arrays With High Filling Factors And Application Of Its Structure On OLED

Microlens array(MLAs)is one of the hot spots in recent years and has been widely used in various fields.As a kind of light source with rapid development in recent years,Organic Light Emitting Device(OLED)is considered as a new generation lighting and display device after liquid crystal display(LCD)because of its advantages,including wide viewing angle,spectrum close to natural light,low energy consumption,long service life,high luminous efficiency and flexible display.However,due to the large refractive index difference between the OLED device substrate and the air medium,the photons generate reflection and refraction,resulting in that most of the photons cannot escape into the air,so the light extraction efficiency of the OLED is low.The attachment of MLAs to the OLED surface has proved convenient and effective as a way to improve the light extraction efficiency of the OLED.In this paper,the methods of fabricating MLAs with high fill factor on photoresist films by photolithography,thermal reflow,Parylene vapor deposition process,and ultraviolet nano-imprinting technology are introduced,and the effects of different MLAs structures on the performance of OLED are studied.First,according to the theory of MLAs template design,the MLAs template is designed.Circular,hexagonal and square MLAs arrays are prepared by photolithography and thermal reflow,and then a layer of Parylene film is deposited on the reflowed MLAs template by vapor deposition to further improve the fill factor of the MLAs template.Finally,the structure of the prepared MLAs template is replicated on the surface of the OLED by using the ultraviolet nano-imprinting method to improve the luminous performance.The scanning electron microscope was used to characterize the MLAs replicated by the template prepared by traditional photolithography and thermal reflux,and the MLAs replicated by the template after the Parylene vapor deposition was also characterized.The results show that the filling factor of MLAs prepared by using Parylene film deposited on MLAs template can be effectively increased.The optical microscope results show that the MLAs with different shapes have good imaging ability,and the MLAs after coating has better focusing ability and imaging performance.Finally,the MLAs structure is applied to OLED.The luminous performance of OLED is improved.The current efficiency of the OLED in which the circular MLAs replicated from the template after vapor deposition of Parylene was attached was increased by about 42% at most.Therefore,that preparation of the MLAs of the photoresist film by utilizing the photoetch,the thermal reflux,the vapor deposition Parylene plating process and the ultraviolet nano-imprinting technology is a simple and low-cost process,and the prepared micro lens array can effectively improve the performance of the OLED.