A new monolithic polymer micro lens array (MLA) that mimics the structure of insect eyes has been developed by a research team led by Professor Ki-Hun Jeong from the Department of Bio and Brain Engineering. The nanostructure allows for the reduction of reflectance to as low as 1% while also being cheaper to produce than conventional lenses, which have a reflectance of 10%.

Because the new lens can be produced using current manufacturing methods, Professor Jeong expects that commercialization of the new technology should be relatively straightforward. Professor Jeong also stresses that the nanostructure of the lens surface also negates the need for applying multiple layers of anti-reflective coating, a costly process, making this new lens much cheaper to manufacture as well.

Additionally, the new lens is better at focusing light, which should improve photon collection onto image sensor arrays such as charge-coupled devices or complementary metal–oxide–semiconductors, and will most likely see application in the development of high sensitivity cameras, as well as normal digital cameras.

Fabrication of the lens was done by incorporating a silver annealed a nano-island mask and isotropic dry etching on the lens surfaces. Polymer MLAs were prepared on a soda-lime glass wafer by using a conventional resist melting method and a positive tone photoresist was initially defined with cylindrical micro-patterns by using photolithography. The micro-pattern arrays were then reflowed and hardened by thermal cross-linking in a convection oven. Antireflective nanostructures were directly fabricated over the curved surface of MLAs by using isotropic etching with a silver annealed nano-island mask. First, a thin silver film was directly deposited on the MLAs by thermal evaporation. Next, the polymer lens surface was isotropically etched with the silver nano-island mask by using oxygen plasma. Finally, the silver nano-islands were selectively removed with a wet etchant without any damage of the polymer MLAs.

On November 12, the findings were published in the journal, Applied Physics Letters.