Patent ID: 9568885
Date: 2017-02-14
CPC Classifications: G02B,G03H

Claim:
1. A method of suppressing undesired visible optical artifacts on a substrate comprising the steps of: coating a substrate with a photoresist recording media; placing a holographic optical diffuser, an aperture, and a partial mirror, in that order, in front of the substrate in a first position spaced from the substrate; exposing the substrate in a first step with a laser beam through the holographic optical diffuser, the aperture, and the partial mirror in the first position to form a first microstructure of a certain size and the diffused laser beam reflected off the photoresist recording media is re-reflected back by the partial mirror onto the photoresist recording media to form a second microstructure overlaid on the first microstructure and different in size from said first microstructure; whereby said second microstructure suppresses the undesired visible optical artifacts.