Tin-Activated Calcium Orthosilicate Phosphors

A study of the tin‐activated calcium orthosilicates disclosed two phosphors: a blue‐emitting phosphor with a very broad excitation band having the β ‐ Ca 2 SiO 4 structure and a yellow‐emitting phosphor with fair response to high‐pressure mercury‐vapor radiation having the α ′ ‐ Ca 2 SiO 4 structure. The β ‐ Ca 2 SiO 4 : Sn phosphor is the more efficient of the two, comparing very favorably with other well‐known blue phosphors. The efficiency of β ‐ Ca 2 SiO 4 : Sn was studied as a function of activator concentration and compared with similar results for β ‐ CaSiO 3 : Sn . The difference in behavior between β ‐ Ca 2 SiO 4 : Sn and β ‐ CaSiO 3 : Sn is attributed to differences in crystal structure.