Research On Fabrication Of Microlens Array Based On Thermal Reflow Method And Thermal Imprint Method

As modern optical systems are more and more miniaturized,lightweight,and integrated,the components that make up the optical system are also continuously miniaturized and arrayed.For the current stage,the manufacturing process of microlenses still lags behind the theoretical design.Therefore,it is necessary to develop a complete process flow for a manufacturing method.In this paper,the method of thermal reflow of photoresist is selected,and AZ4620 photoresist is selected as the main material.After UV lithography,a cylindrical array on the surface of the silicon substrate is worth.The volume of the photoresist column,the heat reflow time,and the heat reflow temperature are three.The angle explores the factors that affect the microlens array profile.It is found that after sufficient heat reflow at 140℃ for a long time,the area of the bottom of the formed microlens is basically unchanged,and the volume shrinks to about 67% of the original.It provides a direct basis for the micro-lenses with a certain height and diameter to be thermally reflowed into a certain profile.In addition,for the same volume of photoresist column reflowed at the same temperature and different time,and reflowed at the same temperature and different time,these two experimental conditions will have a slight effect on the surface shape of the microlens..In order to find a fast,low-cost,and accurate method of replicating microlenses,this subject tried a hot stamping nickel template fabrication experiment.Directly plating a conductive layer on the surface of the photoresist microlens and then using electroplating to thicken,finally get a nickel template that can be used for roll-to-roll imprinting.The use of nickel sulfamate as the main plating salt in the electroplating process,combined with appropriate additive composition,current density,electroplating temperature and other conditions is conducive to obtaining a low-stress coating,so as to ensure the complete replication of the template surface microstructure.In order to verify the practicability of microlenses,we input the obtained microlens profile parameters into virtuallab fusion simulation software to construct a laser homogenization experimental model.In the designed homogenizing optical system,the Gaussian beam with a beam waist diameter of 200 um was successfully homogenized into a uniform spot with a diameter of about 700 um.