Liquid crystal display device, polarizing plate, and polarizer protection film

Abstract

The invention provides a liquid crystal display device, as well as a polarizer and a protective film suitable for the liquid crystal display device. The liquid crystal display device comprises a backlight light source, two polarizers, and a liquid crystal cell disposed between the two polarizers; the backlight light source being a white light-emitting diode light source; each of the two polarizers comprising a polarizing film and protective films laminated on both sides of the polarizing film; at least one of the protective films being a polyester film having an adhesion-facilitating layer; the polyester film having a retardation of 3,000 to 30,000 nm; and the adhesion-facilitating layer comprising a polyester resin (A) and a polyvinyl alcohol resin (B).

1 . A polarizer comprising a polarizing film and a protective film laminated on the polarizing film,
 wherein the protective film is a polyester film having an adhesion facilitating layer,   wherein the polyester film has an in-plane retardation of more than 3,000 nm and 30,000 nm or less, and   wherein the adhesion-facilitating layer comprises a resin composition comprising a polyester resin (A) and a polyvinyl alcohol resin (B).   
     
     
         2 . The polarizer according to  claim 1 , wherein the in-plane retardation is 7,350 nm or more and less than 10,000 nm. 
     
     
         3 . The polarizer according to  claim 2 , wherein the polyester film has a ratio in-plane of retardation to thickness-direction retardation (Re/Rth) of 0.2 or more and 1.2 or less. 
     
     
         4 . The polarizer according to  claim 1 , wherein the adhesion facilitating layer further comprises a crosslinking agent. 
     
     
         5 . The polarizer according to  claim 4 , wherein the crosslinking agent is a melamine-based compound or an isocyanate-based compound. 
     
     
         6 . The polarizer according to  claim 1 , wherein the acid value of the polyester resin (A) in the adhesion facilitating layer is 20 KOHmg/g or less. 
     
     
         7 . The polarizer according to  claim 1 , wherein the degree of saponification of the polyvinyl alcohol resin (B) in the adhesion facilitating layer is 60 mol % or more and 85 mol % or less. 
     
     
         8 . The polarizer according to  claim 1 , wherein the polyester film has, on the surface opposite to the surface facing the polarizing film, one or more layers selected from the group consisting of a hard-coat layer, an antiglare layer, an antireflection layer, a low-reflection layer, a low-reflection antiglare layer, and an antireflection antiglare layer. 
     
     
         9 . The polarizer according to  claim 1 , wherein the polarizer further comprises a protective film that is a birefringence-free film or a film selected from the group consisting of a triacetyl cellulose film, an acrylic film, and a norbornene film and that is laminated on the polarizing film opposite to the protective film that is a polyester film. 
     
     
         10 . A protective film comprising a polyester film that has an adhesion-facilitating layer comprising a resin composition comprising a polyester resin (A) and a polyvinyl alcohol resin (B), and that has an in-plane retardation of more than 3,000 nm and 30,000 nm or less. 
     
     
         11 . The protective film according to  claim 10 , wherein the in-plane retardation is 7,350 nm or more and less than 10,000 nm. 
     
     
         12 . The protective film according to  claim 11 , wherein the polyester film has a ratio in-plane of retardation to thickness-direction retardation (Re/Rth) of 0.2 or more and 1.2 or less. 
     
     
         13 . The protective film according to  claim 10 , wherein the adhesion facilitating layer further comprising a crosslinking agent. 
     
     
         14 . The protective film according to  claim 13 , wherein the crosslinking agent is a melamine-based compound or an isocyanate-based compound. 
     
     
         15 . The protective film according to  claim 10 , wherein the acid value of the polyester resin (A) in the adhesion facilitating layer is 20 KOHmg/g or less. 
     
     
         16 . The protective film according to  claim 10 , wherein the degree of saponification of the polyvinyl alcohol resin (B) in the adhesion facilitating layer is 60 mol % or more and 85 mol % or less. 
     
     
         17 . The protective film according to  claim 10 , wherein the polyester film has, on the surface opposite to the surface facing with the polarizing film, one or more layers selected from the group consisting of a hard-coat layer, an antiglare layer, an antireflection layer, a low-reflection layer, a low-reflection antiglare layer, and an antireflection antiglare layer.