| 摘要 |
PROBLEM TO BE SOLVED: To obtain a phosphor exhibiting high brilliance, hardly suffering from luminance degradation characteristics and suitable for high-image quality display, and to provide an image display device of high image quality. SOLUTION: A ratio of SiO2 contained in the matrix of a conventional Tb- activated Y2 SiO5 phosphor is caused to be in excess of the stoichiometric ratio by employing a green color-emitting phosphor represented by the general formula: (Y1-y-z My Gdz )1-x Tbx }2 (Si1-b Geb O2 )1+a O3 (wherein 0<x<=1; 0<=y<=1; 0<=z<=1; 0<a<=1; 0<=b<=1; and M is at least one rare earth element selected from the group consisting of Sc, In, La, Lu, Yb, Ce, Eu, Sm, Tm, Ho, Er and Nd). The excess amount (a) of SiO2 is more preferably 0<a<=0.4 when the excess amount is changed in the general formula, and both luminance retention and luminance are far enhanced compared with conventional phosphors within this range. |
