US Patent 7309517 - Silica/Zirconia nanoparticles for durable optical film

http://www.freepatentsonline.com/7309517.html

In order to improve the scratch resistance of brightness enhancing films this patent from 3M teaches the use of silica or zirconia nanoparticles in the film. Claim 1 reads:

1. A durable optical film comprising: a polymerized optical film structure having a microstructured surface and a plurality of substantially fully condensed surface modified colloidal nanoparticles of silica, zirconia, or mixtures thereof.