Oxynitride-based phosphor and light emitting device including the same

A light emitting device, comprising:

• a light emitting element emitting excitation light;
• and
• a wavelength converting unit absorbing the excitation light and emitting visible light,
• wherein the wavelength converting unit includes an oxynitride-based phosphor containing at least calcium (Ca), barium (Ba), silicon (Si), oxygen (O), and nitrogen (N) as host material components in a host material and having a rare-earth element dissolved in the host material as an activator, the rare-earth element being at least one from a group consisting of manganese (Mn), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), dysprosium (Dy), terbium (Tb), holmium (Ho), erbium (Er), thulium (Tm), and ytterbium (Yb), and the host material has a monoclinic crystal structure in which a crystal lattice according to a peak of an X-ray powder diffraction pattern has values of a=7.076, b=23.888, c=4.827, α=γ=90°, and β=109.110° and rates of change of a, b, c, α, β, and γ are respectively 5% or less.

A method of making an oxynitride-based phosphor containing at least calcium (Ca), barium (Ba), silicon (Si), oxygen (O), and nitrogen (N) as host material components in a host material and having a rare-earth element dissolved in the host material as an activator, comprising:

• mixing silicon nitride powder, calcium oxide powder, barium oxide powder, and a rare earth element oxide powder to form a mixture;
• firing the mixture;
• and
• crushing the fired mixture,
• wherein the rare-earth element is at least one from a group consisting of manganese (Mn), cerium (Ce), praseodymium (Pr), neodymium (Nd), samarium (Sm), europium (Eu), gadolinium (Gd), dysprosium (Dy), terbium (Tb), holmium (Ho), erbium (Er), thulium (Tm), and ytterbium (Yb), and
• the host material has a monoclinic crystal structure in which a crystal lattice according to a peak of an X-ray powder diffraction pattern has values of a=7.076, b=23.888, c=4.827, α=γ=90°, and β=109.110° and rates of change of a, b, c, α, β, and γ are respectively 5% or less.