Rapid, direct fabrication of antireflection-coated microlens arrays by photoembossing

Photoembossing is a rapid, low cost process to create surface relief structures in polymer thin films via a reaction/diffusion mechanism. It is demonstrated that this technique can be used to create a microlens array of which the focal length can be easily controlled by tuning the processing parameters. In addition, the technique is shown to be particularly interesting since it does not require any physical contact during the development of the microlens array. Additional coatings (e.g., a solution-processable antireflection coating) can therefore be applied prior to the development of the microlens array when the film is still flat. This stimulates the formation of films with a homogeneous thickness distribution and obviates the use of further postprocessing steps.