Polarizer, optical film using it, image display unit using them

Abstract

A polarizer that can be used for forming a liquid crystal display or an electroluminescent display with less display irregularities and excellent display characteristics is provided. The polarizer contains a dichroic material in a matrix, and its in-plane retardation at a measurement wavelength providing no absorption is in a range of 950 to 1350 nm. The measurement wavelength is preferably a wavelength that the dichroic material provides no absorption, and it is 1000 nm, for example.

1 . A polarizer containing a dichroic material in a matrix, wherein an in-plane retardation at a measurement wavelength providing no absorption is in a range of 950 to 1350 nm.  
   
   
       2 . The polarizer according to  claim 1 , wherein a differential retardation fluctuation (σ) at the measurement wavelength providing no absorption is in a range of −5 nm/mm to 5 nm/mm.  
   
   
       3 . The polarizer according to  claim 1 , wherein at the measurement wavelength providing no absorption, a distance between a measurement position providing a maximum value of the in-plane retardation and a measurement position providing a minimum value of the in-plane retardation is in a range not more than 10 mm or not less than 100 mm, and a difference between the maximum value and the minimum value (in-plane retardation variation) is less than 60 nm.  
   
   
       4 . The polarizer according to  claim 1 , wherein the measurement wavelength is in a range of 800 to 1500 nm.  
   
   
       5 . The polarizer according to  claim 4 , wherein the measurement wavelength is 1000 nm.  
   
   
       6 . The polarizer according to  claim 1 , wherein the matrix is a polymer film.  
   
   
       7 . The polarizer according to  claim 6 , wherein the polymer film is a polyvinyl alcohol film.  
   
   
       8 . The polarizer according to  claim 1 , which is chip-cut.  
   
   
       9 . An optical film comprising the polarizer according to  claim 1 .  
   
   
       10 . The optical film according to  claim 9 , which further comprises a transparent protective layer, and the transparent protective layer is arranged on at least one surface of the polarizer.  
   
   
       11 . The optical film according to  claim 9 , wherein a pressure-sensitive adhesive layer is arranged on at least one outermost surface layer.  
   
   
       12 . The optical film according to  claim 9 , which further comprises at least either a polarization converter or a retardation film.  
   
   
       13 . The optical film according to  claim 12 , wherein the polarization converter is either an anisotropic reflective polarizer or an anisotropic light-scattering polarizer.  
   
   
       14 . A liquid crystal panel comprising at least the polarizer according to  claim 1 , wherein the polarizer is arranged on at least one surface of a liquid crystal cell.  
   
   
       15 . A liquid crystal display comprising the liquid crystal panel according to  claim 14 .  
   
   
       16 . The liquid crystal display according to  claim 15 , which has a flat light source for emitting polarized light.  
   
   
       17 . An image display device comprising at least the polarizer according to  claim 1 .  
   
   
       18 . The image display device according to  claim 17 , which is an electroluminescent display.  
   
   
       19 . An in-house production method for producing the image display device according to  claim 17 , which comprises a process of chip-cutting at least a polarizer containing a dichroic material in a matrix, wherein an in-plane retardation at a measurement wavelength providing no absorption is in a range of 950 to 1350 nm, and immediately bonding to the display device.  
   
   
       20 . A liquid crystal panel comprising at least the optical film according to  claim 9 , wherein the optical film is arranged on at least one surface of a liquid crystal cell.  
   
   
       21 . A liquid crystal display comprising the liquid crystal panel according to  claim 20 .  
   
   
       22 . The liquid crystal display according to  claim 21 , which has a flat light source for emitting polarized light.  
   
   
       23 . An image display device comprising at least the optical film according to  claim 9 .  
   
   
       24 . The image display device according to  claim 23 , which is an electroluminescent display.  
   
   
       25 . An in-house production method for producing the image display device according to  claim 17 , which comprises a process of chip-cutting at least an optical film comprising a polarizer, the polarizer containing a dichroic material in a matrix, wherein an in-plane retardation at a measurement wavelength providing no absorption is in a range of 950 to 1350 nm, and immediately bonding to the display device.