Method for preparing a β-SiAlON phosphor

A method for preparing a β-SiAlON phosphor, the method comprising:

• weighing starting materials in order to prepare the β-SiAlON phosphor represented by Formula:
• Si(6-x)AlxOyN(8-y):Lnz (wherein Ln is a rare earth element, and the following requirements are satisfied:
• 0<x≦4.2, 0<y≦4.2 and 0<z≦1.0),
• mixing the starting materials to prepare a raw material mixture;
• and
• firing the raw material mixture in a nitrogen-containing atmospheric gas, wherein the starting materials comprise:
• a host raw material including a silicon raw material including a metallic silicon and optionally a silicon compound, and at least one aluminum raw material selected from the group consisting of a metallic aluminum and an aluminum compound, wherein at least one of the silicon raw material and the aluminum raw material contains both metal and compound;
• and
• at least one activator raw material selected from rare earth elements for activating the host raw material,
• wherein the method further comprises the step of adjusting a mixture ratio of the metallic silicon to the silicon compound to control the particle size distribution of the β-SiAlON phosphor such that the mixture ratio of the metallic silicon to the silicon compound is greater than 1.