Dexerials Corporation

Hirofumi Tani

Yasushi Ito

Yoshifumi Ueno

Tomomitsu Hori

Tsuneo Kusunoki

Masahide Daimon

Provided is an illumination device that can be made thin and increases the efficiency of extracting light to the outside. The present invention is provided with: light-emitting structures wherein a blue light-emitting element is embedded in a transparent resin having a convex surface shape; a substrate wherein the light-emitting structures are disposed two-dimensionally; a diffuser plate that diffuses the blue light of the blue light-emitting elements; and a fluorescent sheet that is disposed spaced from the substrate and that contains a particulate fluorescent body that obtains a white light from the blue light of the blue light-emitting elements.

Illumination apparatus

In order to suppress the chromaticity shift and corrosion associated with the deterioration of a sulfide phosphor particle, this phosphor sheet is produced using a phosphor particle-containing resin composition which comprises: covered phosphor particles; polymerizable compound; and a polymerization initiator. The covered phosphor particles are obtained by covering phosphor particles with silicon dioxide films, wherein among the phosphor particles, at least sulfide phosphor particles are covered with silicon dioxide films that contain a metal oxide powder. Thus, the phosphor sheet can be inhibited from emitting a sulfur-based gas, and exhibits a minimized chromaticity shift, even when the phosphor sheet is present in such a manner that the edge of the phosphor layer of the sheet is in an exposed state.

Phosphor sheet

A phosphor sheet-forming resin composition uses a low-cost resin material having high light fastness and low visible light absorption and is capable of providing a phosphor sheet at low cost with deterioration of a phosphor due to moisture being suppressed. The phosphor sheet-forming resin composition contains a film-forming resin composition and a powdery phosphor that emits fluorescence when irradiated with excitation light. The film-forming resin composition contains a hydrogenated styrene-based copolymer, and uses a sulfide-based phosphor as the phosphor. Examples of the hydrogenated styrene-based copolymer include hydrogenated products of styrene-ethylene-butylene-styrene block copolymers. CaS:Eu is used as a preferred sulfide-based phosphor.

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Tochigi, Japan

Hirofumi Tani