Compensators for liquid crystal displays

Abstract

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

1 . An optical stack comprising: 
 a) a first liquid crystal layer; and    b) a j-retarder disposed on the liquid crystal layer; wherein the j-retarder comprises a simultaneous biaxially stretched polymeric 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 being 100 nm or less and an absolute value of an out-of-plane retardance being 55 nm or greater.    
   
   
       2 . The optical stack according to  claim 1 , further comprising a second liquid crystal layer wherein the j-retarder is disposed between the first liquid crystal layer and the second liquid crystal layer.  
   
   
       3 . The optical stack according to  claim 1 , further comprising a polarizer layer wherein the first liquid crystal layer is disposed between the j-retarder and the polarizer layer.  
   
   
       4 . The optical stack according to  claim 3 , wherein the polarizer layer is an absorbing polarizer layer.  
   
   
       5 . The optical stack according to  claim 4 , further comprising a reflective polarizer layer wherein the absorbing polarizer layer is disposed between the first liquid crystal layer and the reflective polarizer layer.  
   
   
       6 . An optical stack comprising: 
 a) a polarizer layer; and    b) a j-retarder disposed on the polarizer layer; wherein the j-retarder comprises a simultaneous biaxially stretched polymeric 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 being 100 nm or less and an absolute value of an out-of-plane retardance being 55 nm or greater.    
   
   
       7 . The optical stack according to  claim 6 , wherein the polarizer layer is an absorbing polarizer layer.  
   
   
       8 . The optical stack according to  claim 6 , wherein the polarizer layer is a reflecting polarizer layer.  
   
   
       9 . The optical stack according to  claim 7 , further comprising a reflecting polarizer layer wherein the absorbing polarizer layer is disposed between j-retarder and the reflecting polarizer layer.  
   
   
       10 . A liquid crystal display comprising: 
 a) a first liquid crystal layer;    b) a light modulating device; and    c) a j-retarder disposed disposed between the first liquid crystal layer and the light modulating device; wherein the j-retarder comprises a simultaneous biaxially stretched polymeric 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 being 100 nm or less and an absolute value of an out-of-plane retardance being 55 nm or greater.    
   
   
       11 . The liquid crystal display according to  claim 10 , further comprising a second liquid crystal layer disposed between the j-retarder and light modulating device.  
   
   
       12 . The liquid crystal display according to  claim 10 , further comprising a polarizer layer wherein the first liquid crystal layer is disposed between the j-retarder and the polarizer layer.  
   
   
       13 . The liquid crystal display according to  claim 12 , wherein the polarizer layer is an absorbing polarizer layer.  
   
   
       14 . The liquid crystal display according to  claim 13 , further comprising a reflective polarizer layer wherein the absorbing polarizer layer is disposed between the first liquid crystal layer and the reflective layer.  
   
   
       15 . A liquid crystal display comprising 
 a) a polarizer layer;    b) a light modulating device; and    c) a j-retarder disposed between the polarizer layer and the light modulating device; wherein the j-retarder comprises a simultaneous biaxially stretched polyolefin 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 being 100 nm or less and an absolute value of an out-of-plane retardance being 55 nm or greater.    
   
   
       16 . The liquid crystal display according to  claim 15 , wherein the polarizer layer is an absorbing polarizer layer.  
   
   
       17 . The liquid crystal display according to  claim 15 , wherein the polarizer layer is a reflecting polarizer layer.  
   
   
       18 . The liquid crystal display according to  claim 16 , further comprising a reflecting polarizer layer wherein the absorbing polarizer layer is disposed between the reflecting polarizer layer and the j-retarder.