TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Agent: The light-diffusion agent is silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, and/or antimony oxide. The agent has an average particle diameter of 0.2-100 microns.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Agent: The light-diffusion agent is silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, and/or antimony oxide. The agent has an average particle diameter of 0.2-100 microns.    TECHNOLOGY FOCUS - POLYMERS - Preferred Structure: The epoxy resin has a structure of formula (1).R1,R2=organic acids having bisphenol structure;andn=degree of polymerization.The epoxy resin further contains a cycloaliphatic epoxy resin. The content rate of the epoxy resin having polysulfite structure is 3-30 wt.% with respect to all epoxy resin. Preferred Properties: The light-diffusion agent is unevenly distributed in any one surface side of the resin sheet. The mal-distribution region of the light-diffusion agent in the resin sheet is an area from the surface to 1/50-1/2 of the whole thickness. The ratio of the light-diffusion agent in the mal-distribution region is 0.1-80 wt.%. The resin sheet has an epoxy-resin monolayer or a laminate of 2 epoxy-resin layers. The light-diffusion agent is unevenly or uniformly distributed in the epoxy-resin layer, preferably in the smooth most-external surface side of the epoxy-resin layer. The volume ratio of the light-diffusion agent in one epoxy-resin layer differs from that in the other epoxy-resin layer. The content of light-diffusion agent is 0.1-60 wt.% with respect to the epoxy resin. The absolute value of the difference of the refractive index of the epoxy resin and the refractive index of the light-diffusion agent is 0.03-0.3. The resin sheet further has a hard-coat layer and a gas barrier layer. The resin sheet has a glass transition temperature of 170degreesC or more, a light transmittance of 88% or more, and a fracture strength of more than 45 N.