Anti-reflection sheet, display element and display device

Abstract

An anti-reflection sheet is formed in a manner of forming a resin layer, which has many fine projections 12 , on a flat and smooth surface of a transparent substrate 11 . Transparent resin is molded into the projections 12 , the projections 12 have an almost quadratic function-shaped cross section including a center axis C perpendicular to the surface of the substrate 11 , and a surface of the projection 12 is preferably a rotational paraboloid. A ratio (aspect ratio) b/a of a height b and width a of the projection 12 is 1 or less. Additionally, an arranged pitch P of the projections 12 is not more than half of a wavelength of incident light.

1 . An anti-reflection sheet, wherein a resin layer, in which a plurality of fine projections or recesses are arranged, is formed on a surface of a transparent substrate, the projections or recesses having a shape of a cross section which is in the shape of a quadratic function having a correlation coefficient of 0.8 or more, the cross section including a center axis perpendicular to the surface of the substrate, and an arranged pitch of the projections or recesses is not more than half of a wavelength of incident light. 
     
     
         2 . The anti-reflection sheet according to  claim 1 , wherein the projections or recesses have a quadratic function-shaped cross section including the center axis perpendicular to the surface of the substrate. 
     
     
         3 . The anti-reflection sheet according to  claim 1 , wherein an aspect ratio of the projections or recesses is 1 or less. 
     
     
         4 . The anti-reflection sheet according to  claim 1 , wherein an area occupancy rate of the projections or recesses to an area of the surface of the substrate is 60% or more, viewed in a direction perpendicular to the surface of the substrate. 
     
     
         5 . The anti-reflection sheet according to  claim 1 , wherein a difference between a refractive index n 1  of the substrate and a refractive index n 2  of the projections or recesses satisfies the following expression:
   | n 1 −n 2|≦0.05
 
 
     
     
         6 . The anti-reflection sheet according to  claim 5 , wherein the refractive index n 1  of the substrate is equivalent to the refractive index n 2  of the projections or recesses. 
     
     
         7 . The anti-reflection sheet according to  claim 5 , wherein the difference between the refractive index n 1  of the substrate and the refractive index n 2  of the resin layer having the projections or recesses satisfies the following expression:
   | n 1 −n 2|≦0.02
 
 
     
     
         8 . The anti-reflection sheet according to  claim 1 , wherein the height of the projection or the depth of the recess is 400 nm or less. 
     
     
         9 . The anti-reflection sheet according to  claim 8 , wherein the height of the projection or the depth of the recess is 50 nm or more. 
     
     
         10 . The anti-reflection sheet according to  claim 1 , wherein the thickness of the resin layer having the projections or recesses is 11 μm or more. 
     
     
         11 . The anti-reflection sheet according to  claim 1 , wherein the projections or recesses have a shape rotationally symmetric around the center axis perpendicular to the surface of the substrate. 
     
     
         12 . The anti-reflection sheet according to  claim 1 , wherein the projections or recesses are formed on a face, which is arranged toward an observer, of the substrate. 
     
     
         13 . The anti-reflection sheet according to  claim 1 , wherein the projections or recesses are formed on the face, which is arranged toward an observer, and a face opposite thereto of the substrate. 
     
     
         14 . The anti-reflection sheet according to  claim 1 , wherein the substrate has an adhesive layer on its face opposite to the face on which the resin layer is formed, and a difference between the refractive index n 1  of the substrate and a refractive index n 3  of the adhesive layer satisfies the following expression:
   | n 1 −n 3|≦0.02
 
 
     
     
         15 . A display element, wherein the anti-reflection sheet according to  claim 1  is provided on a surface of a display panel. 
     
     
         16 . A display device comprising:
 a display panel; and   a transparent protective plate arranged opposite to a face on an image generation side of the display panel,   wherein the anti-reflection sheet according to  claim 1  is provided on at least one of both front and back faces of the transparent protective plate.