  The structure of random micro lens array (rMLA) breaks the periodicity of
micro lens array (MLA), suppressing coherence in the homogenization process,
thereby achieving better spot homogenization effects. Sol-gel rMLA exhibits
strong adaptability and high laser tolerance, making it valuable for laser beam
control applications. However, the cracking tendency during the drying process
of sol-gel is a challenge. This paper successfully prepares sol-gel random
micro lens arrays through nanoimprint lithography, thoroughly analyzing the
cracking mechanism and resolving the cracking issue during the drying process
of sol-gel. The manufactured sol-gel random micro lenses exhibit good surface
profile accuracy, uniformity, and excellent light source shaping effects. The
energy utilization efficiency of various types of rMLA is approximately 90%,
with rectangular and hexagonal rMLAs achieving uniformity of light spots of
over 80%.
