Optical film and information technology apparatus comprising the same

Abstract

The present invention relates to an optical film comprising an aromatic based unit having chain having the hydroxy group containing portion and aromatic moiety; and a styrene-based unit comprising one or more styrene-based derivatives, and has absolute values of in-plane retardation (R in ) and thickness retardation (R th ) of 10 nm or less regardless of stretching, and a polarizing plate and an information technology apparatus including the same.

1 . An optical film comprising:
 an aromatic based unit having chain having the hydroxy group containing portion and aromatic moiety; and a styrene-based unit comprising one or more styrene-based derivatives, wherein absolute values of in-plane retardation (R in ) and thickness retardation (R th ) are defined by the following Equation are 10 nm or less regardless of stretching:
     R   in =( n   x   −n   y )× d, R   th =[( n   x   +n   y )/2 −n   z ]×d 
 n x  is the largest refractive index among in-plane refractive indexes of the film, 
 n y  is the refractive index in a direction that is vertical to n x  of the in-plane refractive index of the film, 
 n z  is the thickness refractive index of the film, and 
 d is the thickness of the film. 
   
     
     
         2 . The optical film of  claim 1 , wherein in the optical film, regardless of the stretching, the absolute value of the photoelasticity coefficient is 3×10 −12  m 2 /N or less. 
     
     
         3 . The optical film of  claim 1 , further comprising:
 one or more a (meth)acrylate-based unit that include (meth)acrylate-based derivative.   
     
     
         4 . The optical film of  claim 1 , wherein the content ratio of the aromatic-based unit and the styrene-based unit is in the range of 65 to 75:100 on the basis of mole. 
     
     
         5 . The optical film of  claim 1 , wherein the content ratio of the aromatic-based unit and the styrene-based unit is in the range of 45 to 55:100 on the basis of weight. 
     
     
         6 . The optical film of  claim 3 , wherein the ratio of the sum total of the contents of the aromatic-based unit and the styrene-based unit and the content of the (meth)acrylate-based unit is in the range of 1:99 to 50:50 on the basis of weight. 
     
     
         7 . The optical film of  claim 1 , further comprising:
 a cyclic-based unit having a cyclic moiety.   
     
     
         8 . The optical film of  claim 7 , wherein the cyclic moiety is selected from the group consisting of maleic anhydride, maleimide, glutaric anhydride, glutalimide, lactone and lactame. 
     
     
         9 . The optical film of  claim 3 , wherein the (meth)acrylate-based unit is a copolymer of the (meth)acrylate derivative and a cyclic-based unit having a cyclic moiety. 
     
     
         10 . The optical film of  claim 9 , wherein the cyclic moiety of the cyclic-based unit is selected from the group consisting of maleic anhydride, maleimide, glutaric anhydride, glutalimide, lactone and lactame. 
     
     
         11 . The optical film of  claim 9 , wherein the content of the (meth)acrylate derivative of the copolymer is in the range of about 50% to about 99% on the basis of the weight of the copolymer. 
     
     
         12 . The optical film of  claim 1 , wherein the styrene-based unit is a copolymer of the styrene derivative and the cyclic-based unit having the cyclic moiety. 
     
     
         13 . The optical film of  claim 12 , wherein the cyclic moiety of the cyclic-based unit is selected from the group consisting of maleic anhydride, maleimide, glutaric anhydride, glutalimide, lactone and lactame. 
     
     
         14 . The optical film of  claim 12 , wherein the copolymer includes about 30% to about 99% of styrene-based derivative and about 1% to about 70% of cyclic-based unit on the basis of the weight of the copolymer. 
     
     
         15 . The optical film of  claim 1 , wherein the styrene-based unit forms a copolymer in conjunction with one or more (meth)acrylate-based units. 
     
     
         16 . The optical film of  claim 1 , wherein the aromatic-based unit includes a phenoxy-based resin. 
     
     
         17 . The optical film of  claim 16 , wherein the aromatic-based unit has a number average molecular weight in the range of 1,500 to 2,000,000 g/mol. 
     
     
         18 . The optical film of  claim 1 , wherein the aromatic-based unit includes 5 to 10,000 at least one type of units represented by Formula 1: 
       
         
           
           
               
               
           
         
         wherein X is a divalent group comprising at least one benzene cycle and R is a straight- or branched-chained alkylene group having 1 to 6 carbon atoms. 
       
     
     
         19 . The optical film of  claim 3 , wherein the (meth)acrylate-based unit is the copolymer of the (meth)acrylate derivative and the cyclic-based unit having the cyclic moiety, and the styrene-based unit is the copolymer of the styrene derivative and the cyclic-based unit having the cyclic moiety. 
     
     
         20 . The optical film of  claim 3 , wherein the optical film includes the copolymer of the (meth)acrylate-based unit, the styrene-based unit and the cyclic-based unit. 
     
     
         21 . The optical film of  claim 1 , wherein the optical film is a protective film for polarizer. 
     
     
         22 . A polarizing plate comprising:
 a polarizer; and   the optical film of  claim 1 , which is provided on at least one side of the polarizer.   
     
     
         23 . A liquid crystal display device comprising:
 the polarizing plate of  claim 22 .   
     
     
         24 . An information technology apparatus comprising:
 the optical film of  claim 1 .