SILICONE COMPOSITION FOR ENCAPSULATING LUMINESCENT ELEMENT AND LUMINESCENT DEVICE

A silicone composition for sealing a light emitting element includes: (A) a vinyl group-containing organopolysiloxane having a three-dimensional network structure represented by an average unit formula: (SiO 4/2 ) a (ViR 2 SiO 1/2 ) b (R 3 SiO 1/2 ) c (where Vi represents a vinyl group, R's are identical or different substituted or unsubstituted monovalent hydrocarbon groups other than alkenyl groups, and a, b, and c are positive numbers satisfying that a/ (a + b + c) is 0.2 to 0.6 and b/(a+b+c) is 0.001 to 0.2); (B) an organohydrogenpolysiloxane which has at least two hydrogen atoms, each hydrogen atom being bonded to a silicon atom per molecule, the organohydrogenpolysiloxane being contained in such an amount that an amount of a hydrogen atom bonded to a silicon atom is 0.3 to 3.0 mol per 1mol of a vinyl group bonded to a silicon atom in the component (A) ; and (C) a hydrosilylation catalyst (catalytic amount), wherein a coefficient of linear expansion of the composition after curing is 10 x 10 -6 to 290 x 10 -6 /°C. It is possible to obtain a cured product whose residual stress with a support substrate is reduced and which has long-term satisfactory and stable adhesiveness.