Method of producing roll of laminate strip with polarizing film

Abstract

Disclosed is a method of producing a roll of an optical film laminate strip including a polarizing film which has a thickness of 10 μm or less. The method comprises the steps of: forming a continuous web of optical film laminate including a polarizing film which consists of a polyvinyl alcohol type resin layer and has a thickness of 10 μm or less, wherein the polarizing film is formed by performing an stretching sub-step of subjecting a laminate comprising a continuous web of thermoplastic resin substrate and a polyvinyl alcohol type resin layer formed on the substrate, to a uniaxial stretching in a lengthwise direction of the laminate based on 2-stage stretching consisting of preliminary in-air stretching and in-boric-acid-solution stretching, to attain a stretching ratio of 5 to 8.5 to thereby reduce a thickness of the polyvinyl alcohol type resin layer to 10 μm or less, and an absorption sub-step of causing a dichroic material to be absorbed in the polyvinyl alcohol type resin layer; cutting the continuous web of optical film laminate along a direction parallel to the length direction to form at least one continuous web of laminate strip having a given width; and winding the continuous web of laminate strip having the given width into a roll.

What is claimed is: 
     
         1 . A roll of continuous web of an optical film laminate strip comprising:
 a longitudinally continuous web of a polyvinyl alcohol (PVA) type resin layer, the PVA type resin layer having a thickness of 10 micrometers (μm) or less and having a dichroic material impregnated therein, the dichroic material oriented in said longitudinal direction of the PVA type resin layer, such that the PVA type resin layer having an absorption axis in the longitudinal direction of the web of the PVA type resin layer and having an optical property represented by formulae:
     P >−(10 0.929T-42.4 −1)×100(wherein  T< 42.3); and
 
     P≧ 99.9(wherein  T≧ 42.3); 
   or 
     T≧ 42.5; and 
     P≧ 99.5, 
   where T represents a single layer transmittance and P represents a polarization degree; and   a longitudinally continuous film of a resin laminated onto the PVA type resin layer, wherein the continuous web of the optical film laminate strip has a predetermined width, and the continuous web of the optical film laminate strip is wound into the roll.   
     
     
         2 . The roll of continuous web of the optical film laminate strip in accordance with  claim 1 , wherein said dichroic material comprises iodine which presents in said PVA type resin layer in the optical film laminate strip in a form of a polyiodine ion complex oriented in said longitudinal direction of the PVA type resin layer in the optical film laminate strip. 
     
     
         3 . The roll of continuous web of the optical film laminate strip in accordance with  claim 1 , wherein the resin comprises a thermoplastic resin. 
     
     
         4 . The roll of continuous web of the optical film laminate strip in accordance with  claim 1 , wherein the resin comprises a non-crystallizable resin. 
     
     
         5 . The roll of continuous web of the optical film laminate strip in accordance with  claim 1 , further comprising an optically functional film on a side of the PVA type resin layer opposite the resin layer. 
     
     
         6 . The roll of continuous web of the optical film laminate strip in accordance with  claim 1 , wherein the optically functional film is a biaxial phase difference film having a three-dimensional refractive index, in which refractive indices in triaxial directions have the relation nx>ny>nz. 
     
     
         7 . The roll of continuous web of the optical film laminate strip in accordance with  claim 1 , further comprising a mark formed on the optical film laminate strip, wherein the mark is configured to record defect position information related to the roll of continuous web of the optical film laminate strip. 
     
     
         8 . The roll of continuous web of the optical film laminate strip in accordance with  claim 1 , further comprising a mark formed on the optical film laminate strip, wherein the mark is configured to record defect position information related to the roll of continuous web of the optical film laminate strip. 
     
     
         9 . The roll of continuous web of the optical film laminate strip in accordance with  claim 1 , wherein a crystallization degree of the PVA type resin layer ranges from 27% to 40%. 
     
     
         10 . The roll of continuous web of the optical film laminate strip in accordance with  claim 1 , wherein an orientation function of the PVA type resin layer ranges from 0.05 to 0.35. 
     
     
         11 . The roll of continuous web of the optical film laminate strip in accordance with  claim 1 , wherein an orientation function of the resin layer is less than or equal to 0.10. 
     
     
         12 . The roll of continuous web of the optical film laminate strip in accordance with  claim 1 , further comprising a separator film on a side of the PVA type resin layer opposite the resin layer. 
     
     
         13 . The roll of continuous web of the optical film laminate strip in accordance with  claim 1 , wherein the predetermined width corresponds to one of a long side or a short side of a liquid crystal panel.