Patent ID: 7198831

Claim:
A multi-layer sheet comprising; an optically transparent substrate, a cured pressure-sensitive adhesive layer formed by hardening a curable pressure-sensitive layer of a curable pressure-sensitive adhesive sheet in which the curable pressure-sensitive adhesive layer is layered on and integrated with a surface of the optically transparent substrate, and a light-diffusing sheet having a lens surface; a part of a lens element of the lens surface being embedded in a surface of the cured pressure-sensitive adhesive layer, and a layer of air between the lens surface of the light diffusing sheet and said surface of the cured pressure-sensitive adhesive layer, wherein the curable pressure-sensitive adhesive layer comprises a curable pressure-sensitive adhesive composite having a cationically-polymerizable compound, a polymer, and a photocationic polymerization initiator, the said curable pressure-sensitive adhesive layer has a surface roughness R t of 2 μm or less, and a surface of the substrate on which the curable pressure-sensitive adhesive layer is layered, has a surface roughness R t of 2 μm or less, and further wherein the curable pressure-sensitive adhesive layer has a storage modulus of 9.0×10 5 Pa or less, by dynamic viscoelasticity spectrum at 23° C., before hardening, and has a storage modulus of 4.0×10 6 Pa or more, by dynamic viscoelasticity spectrum at 23° C., after hardening.