Sheet polarizer on which light-scattering polarizing element and light-absorption polarizing element are provided in multiyear

Abstract

A polarizing plate comprises a light-scattering polarizing element and a light-absorbing polarizing element. The elements are so arranged that the polarizing transmission axis of the light-scattering polarizing element is essentially parallel to the polarizing transmission axis of the light-absorbing polarizing element. The light-scattering polarizing element has a polarizing layer comprising an optically isotropic continuous phase and an optically anisotropic discontinuous phase.

1 . A polarizing plate comprises a light-scattering polarizing element having a polarizing layer which selectively transmits polarized light and selectively reflects or scatters other polarized light, and a light-absorbing polarizing element having a polarizing layer which selectively transmits polarized light and selectively absorbs polarized light, said elements being so arranged that the polarizing transmission axis of the light-scattering polarizing element is essentially parallel to the polarizing transmission axis of the light-absorbing polarizing element, and said polarizing layer in the light-scattering polarizing element comprising an optically isotropic continuous phase and an optically anisotropic discontinuous phase.  
     
     
         2 . The polarizing plate as defined in  claim 1 , wherein the plate further comprises at least one transparent support.  
     
     
         3 . The polarizing plate as defined in  claim 1 , wherein the minimum difference between the refractive index of the optically isotropic continuous phase and the refractive index of the optically anisotropic discontinuous phase is less than 0.05 where the refractive indices are measured along directions in plane of the polarizing layer.  
     
     
         4 . The polarizing plate as defined in  claim 1 , wherein the optically isotropic continuous phase contains a polymer.  
     
     
         5 . The polarizing plate as defined in  claim 1 , wherein the optically anisotropic discontinuous phase has a mean particle size of 0.01 to 10 μm.  
     
     
         6 . The polarizing plate as defined in  claim 1 , wherein the optically anisotropic discontinuous phase contains a liquid crystal compound.  
     
     
         7 . The polarizing plate as defined in  claim 1 , wherein the optically anisotropic discontinuous phase contains a polymerization product of a liquid crystal compound having a polymerizable group.  
     
     
         8 . The polarizing plate as defined in  claim 1 , wherein the optically anisotropic discontinuous phase contains a compound having a light-orienting group.  
     
     
         9 . The polarizing plate as defined in  claim 1 , wherein the optically anisotropic discontinuous phase is formed by light irradiation of a discontinuous phase containing a compound having a light-orienting group.  
     
     
         10 . The polarizing plate as defined in  claim 1 , wherein the maximum transmittances for all rays is not less than 75% and the minimum transmittances for all rays is less than 60% where the transmittances are measured along polarizing planes perpendicular to plane of the polarizing layer in the light-scattering polarizing element.  
     
     
         11 . The polarizing plate as defined in  claim 1 , wherein the light-absorbing polarizing element has a polarization degree of not lower than 99%.  
     
     
         12 . The polarizing plate as defined in  claim 2 , wherein the transparent support comprises a cellulose triacetate film.  
     
     
         13 . The polarizing plate as defined in  claim 12 , wherein the cellulose triacetate film is formed essentially without use of a halogenated hydrocarbon as a solvent.  
     
     
         14 . The polarizing plate as defined in  claim 1 , wherein the polarizing plate further comprises an optical anisotropic layer containing a discotic compound, and the optical anisotropic layer, the light absorbing polarizing element and the light-scattering polarizing element are arranged in this order.  
     
     
         15 . A liquid crystal display comprising a backlight, a polarizing plate, a liquid crystal cell of twist nematic mode and another polarizing plate in this order, wherein the polarizing plate on the backlight comprises a light-scattering polarizing element having a polarizing layer which selectively transmits polarized light and selectively reflects or scatters other polarized light, and a light-absorbing polarizing element having a polarizing layer which selectively transmits polarized light and selectively absorbs polarized light, said elements being so arranged that the polarizing transmission axis of the light-scattering polarizing element is essentially parallel to the polarizing transmission axis of the light-absorbing polarizing element, and said polarizing layer in the light-scattering polarizing element comprising an optically isotropic continuous phase and an optically anisotropic discontinuous phase.  
     
     
         16 . The liquid crystal display as defined in  claim 15 , wherein the polarizing plate on the backlight further comprises a transparent support and an optical anisotropic layer containing a discotic compound, and wherein the backlight, the light-scattering polarizing element, the light absorbing polarizing element, the transparent support and the optical anisotropic layer are arranged in this order.  
     
     
         17 . A liquid crystal display comprising a backlight, a polarizing plate, a liquid crystal cell of bend alignment mode and another polarizing plate in this order, wherein the polarizing plate on the backlight comprises a light-scattering polarizing element having a polarizing layer which selectively transmits polarized light and selectively reflects or scatters other polarized light, and a light-absorbing polarizing element having a polarizing layer which selectively transmits polarized light and selectively absorbs polarized light, said elements being so arranged that the polarizing transmission axis of the light-scattering polarizing element is essentially parallel to the polarizing transmission axis of the light-absorbing polarizing element, and said polarizing layer in the light-scattering polarizing element comprising an optically isotropic continuous phase and an optically anisotropic discontinuous phase.  
     
     
         18 . The liquid crystal display as defined in  claim 17 , wherein the polarizing plate on the backlight further comprises a transparent support and an optical anisotropic layer containing a discotic compound, and wherein the backlight, the light-scattering polarizing element, the light absorbing polarizing element, the transparent support and the optical anisotropic layer are arranged in this order.  
     
     
         19 . A liquid crystal display comprising a backlight, a polarizing plate, a liquid crystal cell of horizontal aligning mode and another polarizing plate in this order, wherein the polarizing plate on the backlight comprises a light-scattering polarizing element having a polarizing layer which selectively transmits polarized light and selectively reflects or scatters other polarized light, and a light-absorbing polarizing element having a polarizing layer which selectively transmits polarized light and selectively absorbs polarized light, said elements being so arranged that the polarizing transmission axis of the light-scattering polarizing element is essentially parallel to the polarizing transmission axis of the light-absorbing polarizing element, and said polarizing layer in the light-scattering polarizing element comprising an optically isotropic continuous phase and an optically anisotropic discontinuous phase.  
     
     
         20 . The liquid crystal display as defined in  claim 17 , wherein the polarizing plate on the backlight further comprises a transparent support and an optical anisotropic layer containing a discotic compound, and wherein the backlight, the light-scattering polarizing element, the light absorbing polarizing element, the transparent support and the optical anisotropic layer are arranged in this order.  
     
     
         21 . An optical film comprising a transparent support and a polarizing layer which selectively transmits polarized light and selectively reflects or scatters other polarized light, said polarizing layer comprising an optically isotropic continuous phase and an optically anisotropic discontinuous phase, wherein the maximum transmittances for all rays is not less than 75% and the minimum transmittances for all rays is less than 60% where the transmittances are measured along polarizing planes perpendicular to plane of the polarizing layer.  
     
     
         22 . The optical film as defined in  claim 21 , wherein the minimum difference between the refractive index of the optically isotropic continuous phase and the refractive index of the optically anisotropic discontinuous phase is less than 0.05 where the refractive indices are measured along directions in plane of the film.  
     
     
         23 . The optical film as defined in  claim 21 , wherein the optically anisotropic discontinuous phase contains a liquid crystal compound.  
     
     
         24 . The optical film as defined in  claim 23 , wherein the liquid crystal compound has a characteristic birefringence of not less than 0.10.  
     
     
         25 . The optical film as defined in  claim 21 , wherein the optically anisotropic discontinuous phase contains a polymerization product of a liquid crystal compound having a polymerizable group.  
     
     
         26 . The optical film as defined in  claim 21 , wherein the optically anisotropic discontinuous phase has a mean particle size of not larger than 1.0 μm.  
     
     
         27 . The optical film as defined in  claim 21 , wherein the polarizing layer is formed by stretching the layer at a stretching ratio of not more than 3.0.