Encapsulant for optical semiconductor device and optical semiconductor device using same

Abstract

The present invention provides a sealant for an optical semiconductor device which is less likely to reduce its luminance and is also less likely to change its color even used in an energized state in harsh environments of high temperature and high humidity. The sealant for an optical semiconductor device includes: a first organopolysiloxane not containing a hydrogen atom bound to a silicon atom, but containing an alkenyl group bound to a silicon atom and an aryl group bound to a silicon atom, a second organopolysiloxane containing a hydrogen atom bound to a silicon atom and an aryl group bound to a silicon atom, and a platinum-alkenyl complex. The platinum-alkenyl complex is a reaction product obtained by reacting chloroplatinic acid hexahydrate with not less than 6 equivalent of a bi- or more-functional alkenyl compound. The ratio of the number of the alkenyl group bound to a silicon atom in the organopolysiloxane to the number of the hydrogen atom bound to a silicon atom in the organopolysiloxane in the sealant is not less than 1.0 and not more than 2.5.