Oxynitride phosphor and light-emitting instrument

Abstract

The invention has for its object the provision of an oxynitride fluorescent material has higher emission luminance than conventional rare earth element-activated sialon fluorescent materials. To this end, an oxynitride fluorescent material is designed in such a way as to contain as the primary constituent a JEM phase represented by a general formula MA1(Si 6−z Al z )N 10−z O z wherein M is one or two or more elements selected from the group consisting of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu. For instance, this fluorescent material has a fluorescent spectrum maximum emission wavelength of 420 nm to 500 nm inclusive and an excitation spectrum maximum emission excitation wavelength of 250 nm to 400 nm inclusive.

1 . An oxynitride fluorescent material, which contains as a main component a JEM phase represented by a general formula MA1(Si6−zAlz)N10−zOz wherein M is one or two or more elements selected from the group consisting of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu.  
   
   
       2 . The oxynitride fluorescent material according to  claim 1 , which comprises a JEM phase as a mother crystal with M1 as a luminescence center, wherein M1 is one or two or more elements selected from the group consisting of Ce, Pr, Nd, Sm, Eu, Gd, Th, Dy, Ho, Er, Tm, Yb and Lu.  
   
   
       3 . The oxynitride fluorescent material according to  claim 1 , which contains at least La and an element M1 wherein M1 is one or two or more elements selected from the group consisting of Ce, Pr, Nd, Sm, Eu, Gd, Th, Dy, Ho, Er, Tm, Yb and Lu.  
   
   
       4 . The oxynitride fluorescent material according to  claim 1 , which contains at least Ce.  
   
   
       5 . The oxynitride fluorescent material according to  claim 3 , which contains at least Eu.  
   
   
       6 . The oxynitride fluorescent material according to  claim 3 , which contains at least Tb.  
   
   
       7 . The oxynitride fluorescent material according to  claim 3 , which contains at least Ce and Tb.  
   
   
       8 . An oxynitride fluorescent material, which contains elements M, Si, Al, O and N where M is one or two or more elements selected from the group consisting of La, Ce, Pr, Nd, Sm, Eu, Gd, Th, Dy, Ho, Er, Tm, Yb and Lu, and which has a composition represented by a compositional formula MaSibAlcOdNe where a=1, and satisfying all conditions: 
         b =(6 −z )× f   (i)   c =(1 +z )× g   (ii)   d=z×h   (iii)   e =(10 −z )× i   (iv) 0.1≦z≦3  (v) 0.7≦f≦1.3  (vi) 0.7≦g≦3  (vii) 0.7≦h≦3  (viii)   0.7 ≦i≦1.3  (ix) 
   
   
       9 . The oxynitride fluorescent material according to  claim 8 , wherein f=g=h=i=1.  
   
   
       10 . The oxynitride fluorescent material according to  claim 8 , wherein z=1.  
   
   
       11 . The oxynitride fluorescent material according to  claim 8 , wherein M is Ce.  
   
   
       12 . The oxynitride fluorescent material according to  claim 8 , wherein M contains at least two elements La and Ce.  
   
   
       13 . The oxynitride fluorescent material according to  claim 8 , wherein M contains at least two elements La and Eu.  
   
   
       14 . The oxynitride fluorescent material according to  claim 8 , wherein M contains at least two elements La and Tb.  
   
   
       15 . The oxynitride fluorescent material according to  claim 8 , wherein M contains at least three elements La, Ce and Tb.  
   
   
       16 . The oxynitride fluorescent material according to  claim 1 , which contains at least two elements La and Ce, wherein a ratio of La and Ce (a ratio of the number of atoms in the composition) is 0.01≦Ce/La≦10.  
   
   
       17 . The oxynitride fluorescent material according to  claim 1 , which contains at least two elements La and Eu, wherein a ratio of La and Eu (a ratio of the number of atoms in the composition) is 0.001≦Eu/La≦1.  
   
   
       18 . The oxynitride fluorescent material according to  claim 1 , which contains at least two elements La and Tb, wherein a ratio of La and Tb (a ratio of the number of atoms in the composition) is 0.01≦Tb/La≦10.  
   
   
       19 . The oxynitride fluorescent material according to  claim 1 , which contains at least three elements La, Ce and Tb, wherein a ratio of La, Ce and Tb (a ratio of the number of atoms in the composition) is 0.01≦(Ce+Tb)/La≦10.  
   
   
       20 . The oxynitride fluorescent material according to  claim 4 , wherein a fluorescence spectrum has a maximum emission wavelength of 420 nm to 500 nm inclusive and an excitation spectrum has a maximum excitation wavelength of 250 nm to 400 nm inclusive.  
   
   
       21 . The oxynitride fluorescent material according to  claim 6 , wherein a fluorescence spectrum has a maximum emission wavelength of 480 nm to 560 nm inclusive and an excitation spectrum has a maximum excitation wavelength of 200 nm to 300 nm inclusive.  
   
   
       22 . The oxynitride fluorescent material according to  claim 1 , which comprises a mixture of the JEM phase and other crystal phase or an amorphous phase, wherein said mixture has a JEM content of 50% by mass or greater.  
   
   
       23 . A lighting device, comprising an emission light source and a fluorescent material, wherein a fluorescent material as recited in  claim 1  is at least used.  
   
   
       24 . The lighting device according to  claim 23 , wherein said emission light source is an LED that emits light having a wavelength of 330 nm to 420 nm.  
   
   
       25 . The lighting device according to  claim 23 , wherein said emission light source is an LED that emits light having a wavelength of 330 nm to 420 nm, and a fluorescent material as recited in any one of  claims 1  to  22 , a green fluorescent material that emits light having a wavelength of 520 nm to 570 nm inclusive in response to excitation light of 330 run to 420 nm and a red fluorescent material that emits light having a wavelength of 570 nm to 770 nm inclusive in response to excitation light of 330 nm to 420 nm are used to mix together red light, green light and blue light, emitting white light.  
   
   
       26 . The lighting device according to  claim 23 , wherein said emission light source is an LED that emits light having a wavelength of 330 nm to 420 nm, and a fluorescent material as recited in any one of  claims 1  to  22  and a yellow fluorescent material that emits light having a wavelength of 550 nm to 600 nm inclusive in response to excitation light of 330 nm to 420 nm are used to mix together yellow light and blue light, emitting white light.  
   
   
       27 . The lighting device according to  claim 26 , wherein said yellow fluorescent material is a Ca-α-sialon with Eu in the form of a solid solution.  
   
   
       28 . An image display comprising an excitation source and a fluorescent material, wherein a fluorescent material as recited in  claim 1  at least used.  
   
   
       29 . The image display according to  claim 28 , which is any one of a vacuum fluorescent tube (VFD), a field emission display (FED), a plasma display panel (PDP), and a cathode-ray tube (CRT).