A surface of a phosphor particle is coated with a coating member made of a
material that is different from the phosphor in chemical vapor-phase
reaction. The coating member is made of any of metal oxide, metal nitride
and metal oxynitride. The coating member coats the surface of the
phosphor with a substantially smooth film, or is formed such that a large
number of fine particles, which are relatively smaller than the phosphor
particle, aggregate to coat the whole surface of the phosphor particle.
The coating member contains at least one metallic element selected from
the group including Al, Si, and rare earth elements. In addition, the
phosphor is a transparent water-soluble phosphor and is an alkaline-earth
silicon-nitride phosphor, an alkaline-earth silicon oxynitride phosphor,
or the like. A BET value of the coated phosphor is 1.0 to 10 times the
BET value before coating. The average thickness of the coating is 10 nm
to 500 nm.