Multilayer optical film

Abstract

Thermoplastic birefringent multilayer optical films are described. More particularly, thermoplastic multilayer films having alternating first and second layers having a linear layer profile where both outer layers are thinner than 350 nm but thicker than 150 nm are described. Thermoplastic birefringent multilayer optical films with thinner outer protective boundary layers are described.

What is claimed is: 
     
         1 . A multilayer optical film comprising a protective layer disposed between, and coextruded with, a plurality of first layers and a plurality of second layers, each of the first, the second and the protective layers thinner than 350 nm, a total number of the first layers less than 200, a total thickness of the protective layer and the plurality of the first layers less than 30 microns, at least one of the first and the second layers having birefringence, wherein a minimum average delamination between the protective layer and the plurality of the first layers is greater than 100 g/in. 
     
     
         2 . The multilayer optical film of  claim 1 , wherein the protective layer is thinner than 200 nm. 
     
     
         3 . The multilayer optical film of  claim 1 , wherein the protective layer is thinner than 150 nm. 
     
     
         4 . The multilayer optical film of  claim 1 , wherein the protective layer is about as thick as a thickest first layer in the plurality of the first layers. 
     
     
         5 . The multilayer optical film of  claim 1  being thinner than 30 microns. 
     
     
         6 . The multilayer optical film of  claim 1  being thinner than 20 microns. 
     
     
         7 . The multilayer optical film of  claim 1  being thinner than 17 microns. 
     
     
         8 . The multilayer optical film of  claim 1 , wherein the protective layer includes a same material as one the first or and the second layers. 
     
     
         9 . A backlight comprising the multilayer optical film of  claim 1 . 
     
     
         10 . The multilayer optical film of  claim 1  being a reflective polarizer. 
     
     
         11 . The multilayer optical film of  claim 1  being a mirror.