Method for stacking surface structured optical films

Abstract

A display includes an optical film that has a surface structure, such as a prismatically structured surface for increasing the brightness of the display. The structured surface is bonded to an opposing surface of a second film using a layer of adhesive, by penetrating the structured surface into the adhesive layer to a depth less than a feature height of the structured surface. The bonded film structure provides additional strength to the films and reduces the possibility of film damage during display assembly.

1 . A method for stacking optical films, comprising: 
 pressing prismatic ribs of a prismatically ribbed, first optical film into a first adhesive layer on a surface of a second optical film to a depth so as to leave a gap between portions of the prismatic ribs and the first adhesive layer.    
   
   
       2 . A method as recited in  claim 1 , further comprising passing the first and second optical films from respective rolls, overlapping the first and second optical films, continuously pressing the first and second optical films together, and cutting the first and second optical films to a desired size in a continuous process.  
   
   
       3 . A method as recited in  claim 2 , further including stripping first and second liner layers from the respective first and second optical films.  
   
   
       4 . A method as recited in  claim 2 , wherein cutting the first and second optical films includes cutting through the first and second optical films to a depth that leaves a liner layer associated with one of the optical films uncut.  
   
   
       5 . A method as recited in  claim 2 , further including curing the adhesive layer after pressing the prismatic ribs into the first adhesive layer.  
   
   
       6 . A method as recited in  claim 2 , wherein cutting the first and second optical films includes passing the first and second optical films through a die roller.  
   
   
       7 . A method as recited in  claim 1 , wherein the second optical film is a prismatically ribbed, second optical film having prismatic ribs in a second orientation perpendicular to an orientation of the prismatic ribs on the first optical film.  
   
   
       8 . A method as recited in  claim 1 , further comprising stacking the first and second optical films with at least a third optical film to form a bonded stack.  
   
   
       9 . A method as recited in  claim 8 , wherein the third optical film is a reflective polarizer.  
   
   
       10 . A method as recited in  claim 1 , further comprising feeding at least one of the first and second optical films as a sheet from a sheet feeder so as to overlap the first and second optical films before pressing the prismatic ribs of the first optical film into the first adhesive layer.  
   
   
       11 . A method for stacking optical films, comprising: 
 pressing active refractive surfaces of refractive features of a first optical film into a first adhesive layer on a surface of a second optical film to a predetermined depth so as to leave a gap between the first adhesive layer and portions of the active refractive surfaces, other portions of the active refractive surfaces contacting adhesive of the first adhesive layer.    
   
   
       12 . A method as recited in  claim 11 , wherein the refractive features of the first optical film are prismatic ribs.  
   
   
       13 . A method as recited in  claim 11 , further comprising passing the first and second optical films from respective rolls, overlapping the first and second optical films, pressing the active refractive surfaces of the first optical film into the first adhesive layer in a continuous process, and cutting the first and second optical films to a desired size in a continuous process.  
   
   
       14 . A method as recited in  claim 13 , wherein cutting the first and second optical films includes cutting through the first and second optical films to a depth that leaves a liner layer associated with the second optical film uncut.  
   
   
       15 . A method as recited in  claim 13 , wherein cutting the first and second optical films includes passing the first and second optical films through a die roller.  
   
   
       16 . A method as recited in  claim 11 , wherein the second optical film is a prismatically ribbed, second optical film having prismatic ribs in a second orientation perpendicular to an orientation of the prismatic ribs on the first optical film.  
   
   
       17 . A method as recited in  claim 11 , further including curing the adhesive layer after pressing the prismatic ribs into the first adhesive layer.  
   
   
       18 . A method as recited in  claim 11 , wherein the second optical film is a prismatically ribbed, second optical film having prismatic ribs in a second orientation perpendicular to an orientation of the prismatic ribs on the first optical film.  
   
   
       19 . A method as recited in  claim 11 , further comprising stacking the first and second optical films with at least a third optical film to form a bonded stack.  
   
   
       20 . A method as recited in  claim 19 , wherein the third optical film is a reflective polarizer.  
   
   
       21 . A method as recited in  claim 11 , further comprising feeding at least one of the first and second optical films as a sheet from a sheet feeder so as to overlap the first and second optical films before pressing the prismatic ribs of the first optical film into the first adhesive layer.