Phosphor, method of producing same, and light-emitting device

Abstract

A phosphor includes, as a main component, a compound represented by a general formula (3-a)YO3/2.aCeO3/2.(5-b)AlO3/2.bGaO3/2.cKO1/2.dPO5/2, where a, b, c and d satisfy 0.12≤a≤0.18, 1.50≤b≤3.00, 0.01≤c≤0.08, and 0.01≤d≤0.08.

What is claimed is: 
     
       1. A phosphor including, as a main component, a compound represented by a general formula (3-a)YO 3/2 .aCeO 3/2 .(5-b)AlO 3/2 .bGaO 3/2 .cKO 1/2 .dPO 5/2 , where a, b, c and d satisfy 0.12≤a≤0.18, 1.50≤b≤3.00, 0.01≤c≤0.08, and 0.01≤d≤0.08. 
     
     
       2. The phosphor according to  claim 1 , including the compound in an amount of 70% by weight or more relative to the entire phosphor. 
     
     
       3. The phosphor according to  claim 1 , including the compound in an amount of 90% by weight or more relative to the entire phosphor. 
     
     
       4. The phosphor according to  claim 1 , wherein the phosphor absorbs light having a peak wavelength in a range of 380 to 420 nm to emit light having a peak wavelength in a range of 530 to 550 nm. 
     
     
       5. A light-emitting device comprising:
 a phosphor including, as a main component, a compound represented by a general formula (3-a)YO 3/2 .aCeO 3/2 .(5-b)AlO 3/2 .bGaO 3/2 .cKO 1/2 .dPO 5/2 , where a, b, c and d satisfy 0.12≤a≤0.18, 1.50 b≤3.00, 0.01≤c≤0.08, and 0.01≤d≤0.08; and 
 an excitation light source which emits first light having a peak wavelength in a range of 380 to 420 nm, 
 wherein the phosphor absorbs part of the first light from the excitation light source to emit second light having a longer wavelength than the first light. 
 
     
     
       6. The light-emitting device according to  claim 5 , wherein the phosphor includes the compound in an amount of 70% by weight or more relative to the entire phosphor. 
     
     
       7. The light-emitting device according to  claim 5 , wherein the phosphor includes the compound in an amount of 90% by weight or more relative to the entire phosphor. 
     
     
       8. The light-emitting device according to  claim 5 , wherein the second light is light having a peak wavelength in a range of 530 to 550 nm. 
     
     
       9. A method for producing a phosphor, the phosphor including, as a main component, a compound represented by a general formula (3-a)YO 3/2 .aCeO 3/2 .(5-b)AlO 3/2 .bGaO 3/2 .cKO 1/2 .dPO 5/2 , where a, b, c and d satisfy 0.12≤a≤0.18, 1.50≤b≤3.00, 0.01≤c≤0.08, and 0.01≤d≤0.08, the method comprising:
 preparing a mixture which includes starting materials for the phosphor; and 
 firing the mixture in an atmosphere with an oxygen partial pressure in a range of 10 −6  to 10 −3  atm. 
 
     
     
       10. The method according to  claim 9 , wherein the mixture includes, as a reaction accelerator, a fluorine-containing compound. 
     
     
       11. The method according to  claim 9 , wherein the phosphor includes the compound in an amount of 70% by weight or more relative to the entire phosphor. 
     
     
       12. The method according to  claim 9 , wherein the phosphor includes the compound in an amount of 90% by weight or more relative to the entire phosphor. 
     
     
       13. The method according to  claim 9 , wherein the phosphor absorbs light having a peak wavelength in a range of 380 to 420 nm to emit light having a peak wavelength in a range of 530 to 550 nm.