Polymeric optical film

Abstract

An optical film includes a layer of simultaneous biaxially stretched polyolefin film that is substantially non-absorbing and non-scattering for at least one polarization state of visible light. The layer has x, y, and z orthogonal indices of refraction where at least two of the orthogonal indices of refraction are not equal. The layer has an in-plane retardance of 100 nm or less and an absolute value of an out-of-plane retardance being 55 nm or greater.

1 . An optical film comprising: 
 a layer of extruded simultaneously biaxially stretched polymer film being substantially non-absorbing and non-scattering for at least one polarization state of visible light; and having x, y, and z orthogonal indices of refraction wherein at least two of the orthogonal indices of refraction are not equal, an in-plane retardance of the layer being 100 nm or less and an out-of-plane retardance of the layer being 55 nm or greater.    
   
   
       2 . The optical film according to  claim 1 , wherein the layer of extruded simultaneously biaxially stretched polymer film is a polyolefin film.  
   
   
       3 . The optical film according to  claim 1 , wherein the polymer comprises at least one of: polypropylene, polyethylene, polyester, copolyester, polyacrylate, fluoropolymer, polybutylene, cyclic olefin polymer, poly(4-methyl-1-pentene), polymethacrylate and poly(vinylidene fluoride).  
   
   
       4 . The optical film according to  claim 1 , wherein the polymer comprises a copolymer of polypropylene and polyethylene.  
   
   
       5 . The optical film according to  claim 1 , wherein the out-of-plane retardance of the layer of extruded simultaneously biaxially stretched polymer film is greater than 100 nm.  
   
   
       6 . The optical film according to  claim 1 , wherein the out-of-plane retardance of the layer of extruded simultaneously biaxially stretched polymer film is greater than 150 nm.  
   
   
       7 . The optical film according to  claim 1 , wherein the in-plane retardance of the layer of extruded simultaneously biaxially stretched polymer film is less than 20 nm.  
   
   
       8 . The optical film according to  claim 1 , wherein the in-plane retardance of the layer of extruded simultaneously biaxially stretched polymer film is from 20 nm to 50 nm.  
   
   
       9 . An optical film comprising: 
 a layer of extruded simultaneously biaxially stretched polymer film being substantially non-absorbing and non-scattering for at least one polarization state of visible light; and having x, y, and z orthogonal indices of refraction wherein at least two of the orthogonal indices of refraction are not equal, an in-plane retardance of the layer being 100 nm or less and an out-of-plane retardance of the layer being 55 nm or greater and the layer has a length and a width of at least 0.65 meter and the in-plane and out-of-plane retardance are substantially uniform across the length and width.    
   
   
       10 . The optical film according to  claim 9 , wherein the width and length of the layer of extruded simultaneously biaxially stretched polymer film are each at least 1.3 meter.  
   
   
       11 . The optical film according to  claim 9 , wherein the width and length of the layer of extruded simultaneously biaxially stretched polymer film are each at least 1.5 meter.  
   
   
       12 . The optical film according to  claim 9 , wherein the in-plane retardance changes less than 4 nm/cm along the width and length of the layer of extruded simultaneously biaxially stretched polymer film.  
   
   
       13 . The optical film according to  claim 9 , wherein the in-plane retardance changes less than 2 nm/cm along the width and length of the layer of extruded simultaneously biaxially stretched polymer film.  
   
   
       14 . The optical film according to  claim 5 , wherein the in-plane retardance changes less than 1 nm/cm along the width and length of the layer of extruded simultaneously biaxially stretched polymer film.  
   
   
       15 . The optical film according to  claim 9 , wherein the layer of extruded simultaneously biaxially stretched polymer film has a thickness of 5 micrometers to 200 micrometers.  
   
   
       16 . An optical film comprising: 
 a layer of extruded simultaneously biaxially stretched polymer film being substantially non-absorbing and non-scattering for at least one polarization state of visible light; and having x, y, and z orthogonal indices of refraction wherein at least two of the orthogonal indices of refraction are not equal, an in-plane retardance of the layer being 100 nm or less and an out-of-plane retardance of the layer being 55 nm or greater and a thickness of 5 micrometers to 200 micrometers.    
   
   
       17 . The optical film according to  claim 16 , wherein the out-of-plane retardance of the layer of extruded simultaneously biaxially stretched polymer film is greater than 100 nm.  
   
   
       18 . The optical film according to  claim 16 , wherein the out-of-plane retardance of the layer of extruded simultaneously biaxially stretched polymer film is greater than 150 nm.  
   
   
       19 . The optical film according to  claim 16 , wherein the layer of extruded simultaneously biaxially stretched polymer film has a thickness of 5 micrometers to 25 micrometers.  
   
   
       20 . The optical film according to  claim 16 , wherein the layer of extruded simultaneously biaxially stretched polymer film has a thickness of 7 micrometers to 75 micrometers.