Patent ID: 8791488

Claim:
A surface treated phosphor comprising: a phosphor matrix including an alkaline earth metal and silicon; and a surface treatment layer including an alkaline earth metal, silicon, and a specific element belonging to groups 4 to 6 of the periodic table, wherein, when element distribution of the surface treatment layer in the thickness direction viewed in cross-section is determined by electron microscopy and energy dispersive X-ray spectroscopy coupled with the electron microscopy, the position representing the maximum peak of the specific element content is located closer to an upper surface of the surface treatment layer than the position representing the maximum peak of a silicon content in the surface treatment layer and silicon contents of the phosphor matrix and the surface treatment layer satisfy the following formula (1): [Formula 1] S 1 <S 2 (1) wherein S 1 represents the silicon content in the phosphor matrix and S 2 represents the silicon content in the surface treatment layer.