Light diffusion member, back light assembly including the same and display device including the same

Abstract

The light diffusion member includes a light diffusing body and a light diffusing layer. The light diffusing body includes a polymer mixture obtained by uniformly blending a first polymer having a first glass transition temperature and a second polymer having a second transition temperature higher than the first transition temperature. Alternatively, the light diffusing body includes a copolymer prepared from the first and the second polymer. The light diffusing body diffuses an incident light through a light exiting surface. The light diffusing layer is formed on the light exiting surface of the light diffusing body and includes a binder resin having beads. A back light assembly including the light diffusion member and a liquid crystal display device including the light diffusion member exhibit an improved luminance and an improved light diffusing efficiency.

1 . A light diffusion member comprising: 
 a light diffusing body including a polymer mixture having a first polymer having a first glass transition temperature and a second polymer having a second glass transition temperature higher than the first transition temperature, the first and second polymers uniformly blended within the polymer mixture, the light diffusing body diffusing an incident light through a light exiting surface of the light diffusing body; and    a light diffusing layer formed on the light exiting surface of the light diffusing body, the light diffusing layer including a binder resin having beads.    
   
   
       2 . The light diffusion member as claimed in  claim 1 , wherein the light diffusing body is integrally formed with the light diffusing layer forming a solitary unit for the light diffusion member and eliminating gaps between the light diffusing body and the light diffusing layer.  
   
   
       3 . The light diffusion member as claimed in  claim 1 , wherein the polymer mixture has a glass transition temperature higher than the first glass transition temperature and a humidity absorbance lower than the second polymer.  
   
   
       4 . The light diffusion member as claimed in  claim 1 , wherein a glass transition temperature of the polymer mixture is about or greater than 100° C.  
   
   
       5 . The light diffusion member as claimed in  claim 1 , wherein a humidity absorbance of the first polymer is lower than a humidity absorbance of the second polymer.  
   
   
       6 . The light diffusion member as claimed in  claim 1 , wherein the first polymer includes polyester-based polymer.  
   
   
       7 . The light diffusion member as claimed in  claim 6 , wherein the polyester-based polymer is at least one polymer selected from a group consisting of polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphtalate.  
   
   
       8 . The light diffusion member as claimed in  claim 1 , wherein the second polymer is at least one polymer selected from a group consisting of polycarbonate, cyclic olefin copolymer, and polymethyl methacrylate.  
   
   
       9 . The light diffusion member as claimed in  claim 1 , wherein the first glass transition temperature is in a range of from about 70 to about 80° C. and the second glass transition temperature is in a range of from about 130 to about 150° C.  
   
   
       10 . The light diffusion member as claimed in  claim 1 , wherein the beads include at least one polymer selected from a group consisting of polymethyl methacrylate and polyethylene terephthalate.  
   
   
       11 . The light diffusion member as claimed in  claim 1 , wherein the binder resin is an acryl-based resin.  
   
   
       12 . The light diffusion member as claimed in  claim 1 , wherein a thickness of the light diffusing body is in a range of from about 0.7 to about 1.2 mm.  
   
   
       13 . The light diffusion member as claimed in  claim 1 , further comprising an adhesion preventing layer facing the light exiting surface of the light diffusing body.  
   
   
       14 . The light diffusion member as claimed in  claim 13 , wherein the adhesion preventing layer includes at least one polymer selected from a group consisting of polymethyl methacrylate and polyethylene terephthalate.  
   
   
       15 . A light diffusion member comprising: 
 a light diffusing body including a polymer mixture of polyethylene terephthalate/polycarbonate having polyethylene terephthalate and polycarbonate uniformly blended within the polymer mixture, the light diffusing body diffusing incident light through a light exiting surface of the light diffusing body; and    a light diffusing layer formed on the light exiting surface of the light diffusing body and including a binder resin including beads.    
   
   
       16 . The light diffusion member as claimed in  claim 15 , wherein the polymer mixture includes about 20-40% by weight of polyethylene terephthalate and about 60-80% by weight of polycarbonate.  
   
   
       17 . The light diffusion member as claimed in  claim 16 , wherein a glass transition temperature of the polymer mixture is in a range of from about 100 to about 121° C.  
   
   
       18 . A light diffusion member comprising: 
 a light diffusing body including a polymer mixture having a plurality of polymers uniformly blended within the polymer mixture and diffusing an incident light to a light exiting surface of the light diffusing body; and    a light diffusing layer formed on the light exiting surface of the light diffusing body and including a binder resin having beads.    
   
   
       19 . The light diffusion member as claimed in  claim 18 , wherein the polymer mixture exhibits a humidity absorbance proportional to a glass transition temperature thereof.  
   
   
       20 . A light diffusion member comprising 
 a light diffusing body including a copolymer having a first polymer having a first glass transition temperature and a second polymer having a second glass transition temperature higher than the first glass transition temperature, the first and second polymers arranged as repeating units, the light diffusing body diffusing an incident light through a light exiting surface of the light diffusing body; and    a light diffusing layer formed on the light exiting surface of the light diffusing body and including a binder resin having beads.    
   
   
       21 . The light diffusion member as claimed in  claim 20 , wherein each repeating unit includes a layer of one of the first polymer or the second polymer, wherein at least one layer of the first polymer is arranged with at least one layer of the second polymer within the copolymer.  
   
   
       22 . The light diffusion member as claimed in  claim 20 , wherein the light diffusing body is integrally formed with the light diffusing layer forming a solitary unit for the light diffusion member and eliminating gaps between the light diffusing body and the light diffusing layer.  
   
   
       23 . The light diffusion member as claimed in  claim 20 , wherein a glass transition temperature of the copolymer is about or greater than 100° C.  
   
   
       24 . The light diffusion member as claimed in  claim 20 , wherein a humidity absorbance of the first polymer is lower than a humidity absorbance of the second polymer.  
   
   
       25 . The light diffusion member as claimed in  claim 20 , wherein the first polymer includes polyester-based polymer.  
   
   
       26 . The light diffusion member as claimed in  claim 25 , wherein the polyester-based polymer is at least one polymer selected from a group consisting of polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate.  
   
   
       27 . The light diffusion member as claimed in  claim 20 , wherein the second polymer is at least one polymer selected from a group consisting of polycarbonate, cyclic olefin copolymer, and polymethyl methacrylate.  
   
   
       28 . The light diffusion member as claimed in  claim 20 , wherein the first glass transition temperature is in a range of from about 70 to about 80° C. and the second glass transition temperature is in a range of from about 130 to about 150° C.  
   
   
       29 . A light diffusion member comprising: 
 a light diffusing body including a copolymer including polyethylene terephthalate and polycarbonate as repeating units and having a molecular weight of from about 10,000 to about 100,000, the light diffusing body diffusing an incident light through a light exiting surface of the light diffusing body; and    a light diffusing layer formed on the light exiting surface of the light diffusing body and including a binder resin having beads.    
   
   
       30 . The light diffusion member as claimed in  claim 29 , wherein the copolymer includes polyethylene terephthalate and polycarbonate repeatedly by a 1:1.5-4.0 weight ratio.  
   
   
       31 . The light diffusion member as claimed in  claim 30 , wherein a glass transition temperature of the copolymer is in a range of from about 100 to about 121° C.  
   
   
       32 . A light diffusion member comprising: 
 a light diffusing body including a copolymer including a plurality of polymers as repeating units, the light diffusing body diffusing an incident light through a light exiting surface of the light diffusing body; and    a light diffusing layer formed on the light exiting surface of the light diffusing body and including a binder resin having beads.    
   
   
       33 . The light diffusion member of  claim 32 , wherein each repeating unit includes at least one layer of each of the plurality of polymers, wherein each layer is arranged within the copolymer.  
   
   
       34 . The light diffusion member as claimed in  claim 32 , wherein a humidity absorbance of the copolymer is proportional to a glass transition temperature thereof.  
   
   
       35 . A copolymer for a light diffusion member, the copolymer including a first repeating unit of at least one polymer selected from a group consisting of polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate and a second repeating unit of at least one polymer selected from a group consisting of polycarbonate, cyclic olefin copolymer, and polymethyl methacrylate in a mixing ratio of 2-4:6-8 by weight, the copolymer having a glass transition temperature in a range of from about 100 to about 125° C.  
   
   
       36 . The copolymer for the light diffusion member as claimed in  claim 35 , wherein a molecular weight of the copolymer is in a range of from about 10,000 to about 100,000.  
   
   
       37 . The copolymer for the light diffusion member as claimed in  claim 35 , wherein a humidity absorbance of the copolymer is in a range of from about 0.01 to about 1.0%.  
   
   
       38 . A back light assembly comprising: 
 a receiving container;    a light source generating light, the light source received in the receiving container; and    a light diffusion member provided on the light source and including a light diffusing body and a light diffusing layer,    the light diffusing body including a polymer mixture having a first polymer having a first glass transition temperature and a second polymer having a second glass transition temperature higher than the first glass transition temperature, the first and second polymers uniformly blended within the polymer mixture, the light diffusing body diffusing an incident light through a light exiting surface of the light diffusing body,    and the light diffusing layer formed on the light exiting surface of the light diffusing body and including a binder resin having beads.    
   
   
       39 . The back light assembly as claimed in  claim 38 , wherein the first polymer is polyethylene terephthalate and the second polymer is polycarbonate.  
   
   
       40 . The back light assembly as claimed in  claim 39 , wherein the polymer mixture includes about 20-40% by weight of polyethylene terephthalate and about 60-80% by weight of polycarbonate.  
   
   
       41 . The back light assembly as claimed in  claim 38 , wherein a glass transition temperature of the polymer mixture is about or greater than 100° C.  
   
   
       42 . The back light assembly as claimed in  claim 38 , wherein a thickness of the light diffusing body is in a range of from about 0.7 to about 1.2 mm.  
   
   
       43 . The back light assembly as claimed in  claim 38 , further comprising a light collecting member improving a front side luminance and a passivating layer protecting the light collecting member.  
   
   
       44 . A back light assembly comprising: 
 a receiving container;    a light source generating light, the light source received in the receiving container; and    a light diffusion member provided on the light source and including a light diffusing body and a light diffusing layer,    the light diffusing body including a copolymer including a first polymer having a first glass transition temperature and a second polymer having a second glass transition temperature higher than the first glass transition temperature, the first polymer and the second polymer within the copolymer as repeating units, the light diffusing body diffusing an incident light through a light exiting surface of the light diffusing body,    and the light diffusing layer formed on the light exiting surface of the light diffusing body and including a binder resin having beads.    
   
   
       45 . The back light assembly as claimed in  claim 44 , wherein the first polymer is polyethylene terephthalate and the second polymer is polycarbonate.  
   
   
       46 . The back light assembly as claimed in  claim 45 , wherein the polyethylene terephthalate and polycarbonate are polymerized in a mixing ratio of 1:1.5-4.0 by weight.  
   
   
       47 . The back light assembly as claimed in  claim 44 , wherein a glass transition temperature of the copolymer is about or greater than 100° C.  
   
   
       48 . The back light assembly as claimed in  claim 44 , wherein a thickness of the light diffusing body is in a range of from about 0.7 to about 1.2 mm.  
   
   
       49 . A liquid crystal display device comprising: 
 a) a back light assembly comprising:    a receiving container;    a light source generating light, the light source received in the receiving container; and    a light diffusion member provided on the light source and including a light diffusing body and a light diffusing layer,    the light diffusing body including one of a polymer mixture including a first polymer having a first glass transition temperature and a second polymer having a second glass transition temperature higher than the first glass transition temperature, the first and second polymers uniformly blended within the polymer mixture, and a copolymer of the first polymer and the second polymer as repeating units, the light diffusing body diffusing an incident light through a light exiting surface of the light diffusing body,    and the light diffusing layer formed on the light exiting surface of the light diffusing body and including a binder resin having beads; and    b) a display unit provided on the light diffusion member, the display unit changing diffused light into an image light including information.    
   
   
       50 . The liquid crystal display device as claimed in  claim 49 , wherein the first polymer is polyethylene terephthalate and the second polymer is polycarbonate.  
   
   
       51 . The liquid crystal display device as claimed in  claim 50 , wherein the polymer mixture includes about 20-40% by weight of polyethylene terephthalate and about 60-80% by weight of polycarbonate  
   
   
       52 . The liquid crystal display device as claimed in  claim 50 , wherein the copolymer includes polyethylene terephthalate and polycarbonate polymerized in a mixing ratio of about 1:1.5-4.0 by weight.  
   
   
       53 . The liquid crystal display device as claimed in  claim 49 , wherein a glass transition temperature of the polymer mixture and the copolymer is about or greater than 100° C.  
   
   
       54 . The liquid crystal display device as claimed in  claim 49 , wherein a thickness of the light diffusing body is in a range of from about 0.7 to about 1.2 mm.