| abstract |
A highly efficient light-emitting device using a sialon-based phosphor is provided. According to an embodiment, a composition comprising a light emitting element that emits light having a wavelength of 250 nm to 500 nm and a phosphor layer disposed on the light emitting element, wherein the phosphor layer is represented by the following general formula (1). And a phosphor having an average particle diameter of 12 μm or more. (M 1-x1 Eu x1 ) 3-y Si 13-z Al 3 + z O 2 + u N 21-w (1) (In the general formula (1), M is an element selected from a group IA element, a group IIA element, a group IIIA element, a group IIIB element excluding Al, a rare earth element, and a group IVB element. X1, y, z , U, w satisfy the following relationship: 0 <x1 <1, −0.1 <y ≦ 0.3, −3 <z ≦ 1, −3 <u−w ≦ 1.5) [Selection] Figure 1 |