TECHNOLOGY FOCUS - POLYMERS - Preferred Resin: The epoxy resins in the epoxy resin layers (A,B) have dicyclopentadiene-type structure of formula (1). The epoxy resin further contains a cycloaliphatic epoxy resin.R1-R3 = H or linear or branched alkyl group;andn = degree of polymerization.Preferred Sheet: The resin sheet further contains a hard-coat layer containing a urethane resin, and a gas barrier layer.Preferred Properties: The content rates of epoxy resin having the structure (1), and the filler in the epoxy resin layer (A) are respectively 20-75 wt.% and 10-90 wt.% with respect to all epoxy resins. The average particle diameter of the filler is 1 nm to 100 mum. The ratio (d1/d2) of the thickness (d1) of epoxy resin layer (A) and whole thickness (d2) of the resin sheet, is 0.15-0.9. The linear expansion coefficient of the resin sheet at 25-160degreesC is less than 5x10-5/degreesC. The surface roughness (Ra), glass transition temperature (Tg), light transmittance and fracture intensity of the resin sheet are 2 nm or less, 170degreesC or more, 88% or more and 20 N or more, respectively.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Filler: The filler is an inorganic oxide chosen from a group consisting of a soda glass, an alkali-free glass, silica, titanium dioxide, antimony oxide, titania, alumina, zirconia and tungsten oxide. EXAMPLE - Dicyclopentadiene-type epoxy resin (in weight parts) (26.6) having dicyclopentadiene-type structure (formula (1)), 3,4-epoxy cyclohexyl methyl-3,4-epoxy cyclohexane carboxylate (formula (2)) (26.6), methyl hexahydrophthalic anhydride (formula (3)) (48.5) and tetra-n-butyl phosphonium o,o-diethyl phosphorodithioate (formula (4)) (1), were stir-mixed to obtain an epoxy resin liquid. Glass beads (filler) (340) having specific gravity of 2.5 g/cm3 and average particle diameter of 30 mum were added to the obtained epoxy resin liquid (840), and stir-mixed to obtain filler-containing epoxy resin liquid. Urethane acrylate (formula (5)) was suspended to toluene, and 17 wt.% urethane acrylate solution was obtained. The obtained urethane acrylate solution was applied on an endless belt surface and cured to form a hard coat layer with a film thickness of 2 mum. The filler not-containing epoxy resin liquid was then applied on the hard coat layer, and cured at 150degreesC for 10 minutes to form an epoxy resin layer (B) with a thickness of 50 mum. The obtained filler-containing epoxy resin liquid was applied on the epoxy resin layer (B) and cured to form epoxy resin layer (A) of thickness 300 mum. The filler not-containing liquid was again applied on the layer (A) and cured to form layer (B) of 50 mum thickness. Thus, laminate having layer (B) on both surfaces of layer (A) was obtained. The obtained laminate was peeled from the endless belt, left at 180degreesC on a glass plate for 0.5 hours, and cured, to obtain a resin sheet. The obtained resin sheet had light transmittance of 89%, glass transition temperature of 202degreesC, fracture intensity of 40 N and linear expansion coefficient of 4x10-5/degreesC. The resin sheet without any curl and curvatures, had favorable balance between linear expansion coefficient, glass transition temperature and fracture intensity.    R1-R3 = H;and    n = 0.2.