In an LED, when electric power is supplied to a blue light-emitting element through
a pair of leads, light is emitted upward from an upper surface of the blue light-emitting
element and, at the same time, light is radiated from side and lower surfaces of
the blue light-emitting element so that a fluorescent substance is irradiated with
the light. The latter light is reflected by a front surface of the fluorescent
substance or by a concave reflecting mirror serving as a highly reflective material,
so that the reflected light is radiated upward as excitation light (fluorescence)
or as irradiation light. Because a radiating surface of a convex lens is formed
above the concave reflecting mirror, the excitation light and irradiation light
emitted thus are condensed by the convex lens and radiated externally with high
external radiation efficiency.
