| As people continue to pursue high-resolution,low-cost thermal imaging technology,sulphur-based glass microlens arrays have become an urgent need for research into a new type of optical element whose application could significantly contribute to the leapfrogging development of thermal imaging technology.As40Se60glass microlenses have the advantages of inexpensive raw materials,corrosion resistance,low melting point and high refractive index,and can be used in a variety of applications.Sulfur-based glass microlenses will be used in more applications as the use of infrared technology grows,opening up additional opportunities for the advancement of contemporary society.At present,there are problems in the production of sulfur based glass microlens arrays,such as low efficiency,high cost,and technical difficulties.In this paper,the characteristic temperature,viscoelastic response characteristics of As40Se60glass and the crystallization behavior at high temperature were studied by taking the compression molding of As40Se60microlens array as the research objective,and the parameters of the Prony series were obtained by fitting,and the stress distribution and changes of the microlens array under different structural parameters and hot pressing process conditions were simulated.The temperature field change and surface temperature curve of the preparation process of chalcogenide glass were studied,and the volume change of the radial unit of As40Se60glass during the cooling process was simulated,so as to study the internal refractive index distribution and change of the sample during the cooling process.The main conclusions are as follows:（1）It was found that the variance of internal stress distribution decreased from 0.117 to0.061 when the molding temperature increased from 190℃to 210℃,indicating that increasing the temperature could improve the fluidity and homogeneity of the glass.Increasing the interfacial friction coefficient,the equivalent Mises stress decreased first and then increased.When the friction coefficient was 0.4 to 0.6,the equivalent stress was small and homogeneous,indicating that the friction coefficient was adjusted in the proper range.The variance of the internal stress distribution decreases from 0.117 to 0.08 after 1～4 times of repeated molding,which indicates that the stress uniformity can be improved by repeated molding.After adjusting the array structure parameters,the internal stress increases with the increase of the number of sublenses.With the increase of the spacing of adjacent sublenses,the internal stress in the edge region decreases,and the decreasing trend tends to level off when the spacing of sublenses exceeds a certain range.The simulation also found that the ultrasonic vibration can improve the fluidity of the sample and help to increase the filling rate of the sample in the molding.（2）After simulation,comparing the temperature curves and temperature field distribution of different cooling methods.It is found that the cooling rate of the sample surface,water-cooled>air-cooled>asbestos wrapped cooling,and the temperature field distribution of asbestos wrapping method is the most uniform,which is consistent with the experimental results.The simulation study of the sample with uniform refractive index found that if the sample is heated and then cooled.The sample volume and internal density will change during the process,the internal refractive index distribution becomes uneven.And the refractive index of the central region and the edge area of the sample decrease by 0.8%and 1.5%.Respectively,which indicates that the refractive index distribution of the glass blank will change slightly after molding,and the change in the center area is smaller than that in the edge area.（3）After high-temperature annealing of As40Se60sample for 40 hours,it was found that as the temperature increased from 210℃to 240℃,the surface crystalline phase morphology of the sample changed from elliptical to burrs,and then to whiskers The infrared transmittance decreased gradually,but after polishing the heat-treated sample,the transmittance returned to the original level.The infrared transmittance gradually decreases,but after polishing the heat-treated samples.The transmittance returns to the original level,indicating that the crystallization of As40Se60glass starts from the surface and occurs mainly on the surface.While for sulfur glasses with nucleating agents and sulfur glasses with complex compositions.The crystallization takes place both inside and outside.Calculation of the direct and indirect band gaps of As40Se60glass shows that the optical band gap increases with the increase of heat treatment temperature. |
