Fabrication of 3D random microlens array composite optical film with self-assembly

A method for fabricating a microlens array composite optical film by a seamless roller mold of self-assembly is presented. The roller with a lot of random cavities is used to produce a polyethylene terephthalate (PET) composite optical film with 3D random microlens arrays using the ultraviolet (UV) roll-to-roll printing. The luminance gain and haze are 1.247 and 86 %, respectively, giving the PET composite optical film the properties of a brightness enhancement film and a diffuser. Solid glass beads (SBs) are used for parameter testing for self-assembly. Then, 3 M glass bubble beads (BBs) are used to fabricate a seamless roller mold. The optimal parameters of the self-assembly process for the SB are a coating speed of 135 mm/h with a 39 % volume ratio, and those for the BB are a coating speed of 30 mm/h with a 3 % volume ratio. Finally, the PET optical film is used in the green energy lighting testing of a commercial bicycle light-emitting diode (LED). The results show increased lighting angle and light uniformity, making it similar to traditional tungsten light.