Diffusion sheet and manufacturing method thereof

Abstract

A diffusion sheet structure in the direct type backlight module with anti-UV rays function and its manufacturing method discloses a diffusion sheet in the backlight module applied to TFT-LCD TV, and plural layer of the diffusion sheet made by a method of a multi-layer co-extrusion. The diffusion sheet advocates that while producing diffusion layer, at least a ultra-violet rays absorption layer set on the surface of diffusion layer at the same time to achieve insulating ultra-violet rays directly irradiated on the diffusion sheet and to avoid yellow and pyrolysis phenomenon occurred on the diffusion sheet. These results in avoiding the deviation caused from color temperature and chromaticity coordinate of TFT-LCD TV because of yellow diffusion sheet, then to achieve the purpose of improving product quality and materials lifespan.

1 . A structure of diffusion sheet in the direct type backlight module with anti-UV rays comprising: 
 at least a ultra-violet rays absorption layer; and    a diffusion layer;    wherein said ultra-violet rays absorption layer located at least a surface of said diffusion layer.    
     
     
         2 . The structure of diffusion sheet in the direct type backlight module with anti-UV rays as claimed in  claim 1 , wherein said ultra-violet rays absorption layer comprises a resin and a ultra-violet rays absorbent.  
     
     
         3 . The structure of diffusion sheet in the direct type backlight module with anti-UV rays as claimed in  claim 2 , wherein said resin is selected from one of transparency acrylic resin, PMMA (Polymethyl Methacrylate), MS (MMA/Styrene Copolymer) and PC (Polycarbonate), COC (Cycle Olefin Copolymer).  
     
     
         4 . The structure of diffusion sheet in the direct type backlight module with anti-UV rays as claimed in  claim 1 , wherein the thickness of said ultra-violet rays absorption layer is 1˜200 μm.  
     
     
         5 . The structure of diffusion sheet in the direct type backlight module with anti-UV rays as claimed in  claim 1 , wherein said diffusion layer comprises plural light diffusion particles and a substrate.  
     
     
         6 . The structure of diffusion sheet in the direct type backlight module with anti-UV rays as claimed in  claim 5 , wherein said light diffusion particles is selected from one of organic and inorganic materials.  
     
     
         7 . The structure of diffusion sheet in the direct type backlight module with anti-UV rays as claimed in  claim 6 , wherein said light diffusion particles is selected from one of acrylic resin, Titanium Dioxide (TiO 2 ) and Silicon Dioxide (SiO 2 ), Silicon.  
     
     
         8 . The structure of diffusion sheet in the direct type backlight module with anti-UV rays as claimed in  claim 5 , wherein said substrate is selected from one of acrylic resin, PMMA (Polymethyl Methacrylate), MS (MMA Styrene Copolymer) and PC (Polycarbonate), COC (Cycle Olefin Copolymer).  
     
     
         9 . A method of manufacturing diffusion sheet in the direct type backlight module with anti-UV rays comprising the steps of: 
 extruding a diffusion layer by adding a plurality of light diffusion particles into a substrate and using a first extruder;    extrusion a ultra-violet rays absorption layer by adding a ultra-violet rays absorbent into a resin and using a second extruder;    taking said ultra-violet rays absorption layer to touch at least one surface of said diffusion layer by a multi-layer T-die;    co-extruding said diffusion layer and said ultra-violet rays absorption layer to form a plate structure of light diffusion sheet with anti-yellow and well dimensional stability.    
     
     
         10 . The structure of diffusion sheet in the direct type backlight module with anti-UV rays as claimed in  claim 9 , wherein the content of said light diffusion particles is 1˜10 percent of said substrate.  
     
     
         11 . The structure of diffusion sheet in the direct type backlight module with anti-UV rays as claimed in  claim 9 , wherein the increment of said ultra-violet rays absorbent is 1 percent of said resin.  
     
     
         12 . A structure of a diffusion sheet in a direct type backlight module with ultraviolet ray resistance, comprising: 
 a diffusion layer formed by light diffusing particulates disbursed in a first resin, said diffusion layer having first and second opposing sides; and    at least one ultraviolet ray absorption layer overlaying said first side of said diffusion layer, said ultraviolet ray absorption layer being formed by an ultraviolet ray absorbent disbursed in a second resin.    
     
     
         13 . The structure of a diffusion sheet as claimed in  claim 12 , wherein said first and second resin acrylic resin.  
     
     
         14 . The structure of a diffusion sheet as claimed in  claim 12 , wherein said light diffusion particulates are formed by particulates of silicon.  
     
     
         15 . The structure of a diffusion sheet as claimed in  claim 12 , wherein said light diffusion particulates are formed by particulates of titanium dioxide (TiO 2 ).  
     
     
         16 . The structure of a diffusion sheet as claimed in  claim 12 , wherein said light diffusion particulates are formed by particulates of silicon dioxide (SiO 2 ).  
     
     
         17 . The structure of a diffusion sheet as claimed in  claim 12 , further comprising a second ultraviolet ray absorption layer overlaying said second side of said diffusion layer, said second ultraviolet ray absorption layer being formed by said ultraviolet ray absorbent disbursed in said second resin.  
     
     
         18 . A method of manufacturing a diffusion sheet in a direct type backlight module with ultraviolet ray resistance, comprising the steps of: 
 blending a plurality of light diffusion particles into a first resin using a first extruder;    blending an ultraviolet ray absorbent into a second resin using a second extruder;    coupling an output of each of said first extruder and said second extruder to a multi-layer T-die;    co-extruding a diffusion layer output from said first extruder with at least one ultraviolet absorption layer on at least one side of said diffusion layer and output from said second extruder to form a plate structure of a light diffusion sheet with anti-yellowing and dimensional stability characteristics.