Nitride phosphor and method for preparation thereof, and light emitting device
To provide a phosphor containing a comparatively much red component and having high light emitting efficiency, high brightness and further high durability, the nitride phosphor is represented by the general formula L X M Y N ((2/3)X+(4/3)Y) :R or L X M Y O Z N ((2/3)X+(4/3)Y−(2/3)Z) :R (wherein L is at least one or more selected from the Group II Elements consisting of Mg, Ca, Sr, Ba and Zn, M is at least one or more selected from the Group IV Elements in which Si is essential among C, Si and Ge, and R is at least one or more selected from the rare earth elements in which Eu is essential among Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Lu.); contains the another elements.
1. A nitride phosphor having a general formula L X M Y N ((2/3)X+(4/3)Y) :R or a general formula L X M Y O Z N ((2/3)X+(4/3)Y−(2/3)z) :R in which X, Y and Z are 0.5≦X≦3, 1.5≦Y≦8, and 0<Z≦3, L is at least one or more elements selected from the Group II Elements consisting of Mg, Ca, Sr, Ba and Zn, M is at least one or more elements selected from the Group IV Elements in which Si is essential among C, Si and Ge, and R is at least one or more elements selected from the rare earth elements in which Eu is essential among Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Lu, said nitride phosphor absorbing at least a portion of light having a first luminescence spectrum in which a peak wave length is 500 nm or less and emitting light having a second luminescence spectrum which has at least one or more of peaks at a range of 520 to 780 nm is characterized in further containing at least one or more of different elements selected from the Group consisting of Li, Na, K, Rb and Cs.
2. The nitride phosphor according to claim 1 made by firing under a reducing atmosphere.
3. A light emitting device comprising;
a light emitting element which emits light having a first luminescence spectrum which has a peak wave length of 500 nm or less and,
a phosphor which absorbs at least a portion of light having the first luminescence spectrum and emits light having a second luminescence spectrum which has at least one or more of peaks at a range of 520 to 780 nm,
wherein said phosphor is a nitride phosphor having a general formula L X M Y N ((2/3)X+(4/3)Y) :R or a general formula L X M Y O Z N ((2,3)X+(4/3)Y−(2/3)z) :R in which X, Y and Z are 0.5≦X≦3, 1.5≦Y≦8, and 0<Z≦3, L is at least one or more elements selected from the Group II Elements consisting of Mg, Ca, Sr, Ba and Zn, M is at least one or more elements selected from the Group IV Elements in which Si is essential among C, Si and Ge, and R is at least one or more elements selected from the rare earth elements in which Eu is essential among Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er and Lu, said nitride phosphor further containing at least one or more of different elements selected from the Group I Elements consisting of Li, Na, K, Rb and Cs.
4. The light emitting device according to claim 3 ; wherein said device further has one or more phosphors which absorb at least a portion of light having said first luminescence spectrum and at least a portion of light having said second luminescence spectrum and which emit light having the third luminescence spectrum that has at least one or more of peak wave lengths from the blue range to the green range, the yellow range, and the red range.
5. The light emitting device according to claim 4 ; wherein said phosphor emitting the light of said third luminescence spectrum is at least any one or more of a yttrium-aluminum oxide phosphor activated by at least cerium, a yttrium-gadolinium-aluminum oxide phosphor activated by at least cerium, and a yttrium-gallium-aluminum oxide phosphor activated by at least cerium.
6. The light emitting device according to claim 4 ; wherein said device emits white light by mixing portions of 2 or more kinds of light emitted from said light emitting element, emitted from the phosphor having said second luminescence spectrum, and emitted from the phosphor having said third luminescence spectrum.