Wide-acceptance-angle circular polarizers

Abstract

A circular polarizer comprising a single linear polarizer producing a linear state of polarization and at least one phase retardation film layered with the single linear polarizer. In a first embodiment, the at least one phase retardation film includes at least one uniaxial A-plate phase retardation film and at least one uniaxial C-plate phase retardation film. In a second embodiment of the invention, the circular polarizer includes a linear polarizer and at least one biaxial phase retardation film layered with the linear polarizer. In another example of the circular polarize of the second embodiment, at least one uniaxial A-plate phase retardation film and/or at least one uniaxial C-plate phase retardation film is also layer with the linear polarize and the biaxial phase retardation film.

1 . A circular polarizer comprising: 
 a single linear polarizer producing a linear state of polarization;    at least one uniaxial A-plate phase retardation film; and    at least one uniaxial C-plate phase retardation film.    
     
     
         2 . The circular polarizer of  claim 1 , wherein said circular polarizer induces a right-hand circularly polarized light over a range of incident angles between approximately 0° and approximately 85° and over an azimuth of incident plane between approximately 0° and approximately 360° with respect to a transmission axis of said linear polarizer at a single wavelength of incident light.  
     
     
         3 . The circular polarizer of  claim 1 , wherein said circular polarizer induces a left-hand circularly polarized light over a range of incident angles between approximately 0° and approximately 85° and over an azimuth of incident plane between approximately 0° and approximately 360° with respect to a transmission axis of said linear polarizer at a single wavelength of incident light.  
     
     
         4 . The circular polarizer of  claim 1 , wherein said circular polarizer induces a right-hand circularly polarized light over a range of incident angles between approximately 0° and approximately 85° and over an azimuth of incident plane between approximately 0° and approximately 360° with respect to a transmission axis of said linear polarizer in the 450-650 nm spectral range of the incident light.  
     
     
         5 . The circular polarizer of  claim 1 , wherein said circular polarizer induces a left-hand circularly polarized light over a range of incident angles between approximately 0° and approximately 85° and over an azimuth of incident plane between approximately 0° and approximately 360° with respect to a transmission axis of said linear polarizer in the 450-650 nm spectral range of the incident light.  
     
     
         6 . The circular polarizer of  claim 1 , wherein said at least one uniaxial A-plate phase retardation film comprises: 
 a slow axis between approximately between one of approximately +0.1° to approximately +89.9° and approximately −0.1° to approximately −89.9° with respect to the transmission direction of the said linear polarizer; and    a phase retardation of d·Δn=±(0.05λ˜3.5λ), where λ is the wave length of incident light.    
     
     
         7 . The circular polarizer of  claim 1 , wherein the said at least one uniaxial C-plate phase retardation film comprises: 
 a phase retardation of approximately d·Δn=±(0.05λ˜3.5λ), where λ is the wave length of incident light.    
     
     
         8 . The circular polarizer of  claim 1  wherein said circular polarizer is right-hand circular polarized.  
     
     
         9 . The circular polarizer of  claim 1  wherein said circular polarizer is left-hand circular polarized.  
     
     
         10 . A circular polarizer comprising: 
 a single linear polarizer producing a linear state of polarization; and    at least one biaxial phase retardation film.    
     
     
         11 . The circular polarizer of  claim 10 , further comprising: 
 at least one uniaxial A-plate phase retardation film layered with said linear polarizer and said biaxial retardation film.    
     
     
         12 . The circular polarizer of  claim 11 , further comprising: 
 at least one uniaxial C-plate phase retardation film layered with said linear polarizer and said biaxial retardation film.    
     
     
         13 . The circular polarizer of  claim 11 , further comprising: 
 at least one uniaxial C-plate phase retardation film layered with said linear polarizer, said biaxial retardation film, and said at least one uniaxial A-plate phase retardation film.    
     
     
         14 . The circular polarizer of  claim 11 , wherein said at least one biaxial phase retardation film comprises: 
 a slow axis on the plane parallel to a polarizer-retarder surface of said at least one biaxial phase retardation film between one of approximately +0.1° to approximately +89.9° and approximately −0.1° to approximately 89.9° with respect to the transmission direction of the said linear polarizer; and    a phase retardation on the plane parallel to the polarizer-retarder surface of approximately d·Δn=±(0.05λ˜3.5λ); and    a phase retardation on the plane perpendicular to the polarizer-retarder surface of approximately d·Δn=±(0.05λ˜3.5λ) where λ is the wave length of incident light.    
     
     
         15 . The circular polarizer of  claim 12 , wherein said at least one biaxial phase retardation film comprises: 
 a slow axis on the plane parallel to a polarizer-retarder surface of said at least one biaxial phase retardation film between one of approximately +0.1° to approximately +89° and approximately −0.1° to approximately −89° with respect to the transmission direction of the said linear polarizer; and    a phase retardation on the plane parallel to the polarizer-retarder surface of approximately d·Δn=±(0.2λ˜3.5λ); and    a phase retardation on the plane perpendicular to the polarizer-retarder surface of approximately d·Δn=±(0.2λ˜3.5λ) where λ is the wave length of incident light.    
     
     
         16 . The circular polarizer of  claim 12 , wherein said at least one uniaxial A-plate phase retardation film comprises: 
 a slow axis on the plane parallel to a polarizer-retarder surface of said at least one uniaxial A-plate phase retardation film between one of approximately +0.1° to approximately +89.9° and approximately −0.1° to approximately −89.9° with respect to the transmission direction of the said linear polarizer; and    a phase retardation of approximately d.Δn=±(0.05λ˜3.5λ) on the plane parallel to said polarizer-retarder surface where λ is the wavelength of incident light.    
     
     
         17 . The circular polarizer of  claim 13 , wherein said at least one biaxial phase retardation film comprises: 
 a slow axis on the plane parallel to a polarizer-retarder surface of said at least one biaxial phase retardation film between one of approximately +0.1° to approximately +89° and approximately −0.1° to approximately −89° with respect to the transmission direction of the said linear polarizer; and    a phase retardation on the plane parallel to the polarizer-retarder surface of approximately d·Δn=±(0.2λ˜3.5λ); and    a phase retardation on the plane perpendicular to the polarizer-retarder surface of approximately d·Δn=±(0.2λ˜3.5λ) where λ is the wave length of incident light.    
     
     
         18 . The circular polarizer of  claim 13 , wherein the said at least one uniaxial C-plate phase retardation film comprises: 
 a phase retardation of approximately d·Δn=±(0.05λ˜3.5λ), where λ is the wave length of incident light.    
     
     
         19 . The circular polarizer of  claim 14 , wherein said at least one biaxial phase retardation film comprises: 
 a slow axis on the plane parallel to a polarizer-retarder surface of said at least one biaxial phase retardation film between one of approximately +0.1° to approximately +89° and approximately −0.1° to approximately −89° with respect to the transmission direction of the said linear polarizer; and    a phase retardation on the plane parallel to the polarizer-retarder surface of approximately d·Δn=±(0.2λ˜3.5λ); and    a phase retardation on the plane perpendicular to the polarizer-retarder surface of approximately d·Δn=±(0.2λ˜3.5λ) where λ is the wave length of incident light.    
     
     
         20 . The circular polarizer of  claim 14 , wherein said at least one uniaxial A-plate phase retardation film comprises: 
 a slow axis on the plane parallel to a polarizer-retarder surface of said at least one uniaxial A-plate phase retardation film between one of approximately +0.1° to approximately +89.9° and approximately −0.1° to approximately −89.9° with respect to the transmission direction of the said linear polarizer; and    a phase retardation of approximately d·Δn=±(0.05λ˜3.5λ) on the plane parallel to said polarizer-retarder surface where λ is the wavelength of incident light.    
     
     
         21 . The circular polarizer of  claim 14 , wherein the said at least one uniaxial C-plate phase retardation film comprises: 
 a phase retardation of approximately d·Δn=±(0.05λ˜3.5λ), where λ is the wave length of incident light.