A study of the relevant effects on the maximum residual stress in the precision injection moulding of microlens arrays

Microlens arrays are critical components used in various display devices. In this paper, the effects of aperture shape on the value of maximum residual stress have been investigated by both the numerical simulation and experimental methods. The results indicate that the geometrical configuration of the aperture can profoundly influence the levels of residual stresses in precision injection-moulded microlens arrays. The values of maximum residual stresses are found to decrease with the increase of the melt temperature, the mould temperature, and to increase with the increase of the packing pressure for all shapes of the lens arrays, but there is no regular correlation with the flow rate and the packing time over the range of processing parameters used. It is shown that the cooling time has the least effect on the residual stresses. The difference between the simulation and the experimental results is also discussed. The specific surface area (SSA) factor is introduced to describe the geometrical characterization of aperture shapes for the analysis of experimental results.