Light diffusion film fabricated using colloidal lithography and embossing

This study used colloidal lithography in conjunction with imprint lithography (embossing) to fabricate a light diffusion film based on the surface microstructure. An automated system was developed to arrange polystyrene (PS) spheres (diameter of 0.6 to 6 μm) on the substrate surface in a variety of configurations: single layer of spheres with constant diameter, single layer of spheres with multiple diameters, and double layer of spheres with multiple diameters. Optical diffusion testing revealed that PS spheres with a constant diameter created light patterns characterized by concentric circles induced by interference. PS spheres with multiple diameters were shown to reduce the interference. A double layer of spheres of various size presented the best optical diffusion performance. We reduced the effects of scattering between PS spheres through the use of embossing to duplicate the microstructure of the PS spheres, which resulted in outstanding diffusion performance with high transparency.