A Distributed-Index Planar Micro-Lens Made of Plastics

Abstract
A new distributed-index lens, a planar micro-lens, which can be monolithically fabricated on a planar substrate has been realized with optical plastics by means of a monomer exchange technique. A lower index plastic MMA (n=1.494) is diffused into a planar plastic substrate of DAI (n=1.570) with a higher index from around the circular disk mask of 3.6 mmφ. The spot diameter of focused light was as small as 27 µm with a focal length of 25 mm, and a clear image was observed by this lens.