PHOSPHOR AND METHOD FOR PRODUCTION THEREOF, AND APPLICATION THEREOF

• US 20090008663A1
• Filed: 02/23/2006
• Published: 01/08/2009
• Est. Priority Date: 02/28/2005
• Status: Abandoned Application

• Current Assignee: Mitsubishi Chemical Corporation (Mitsubishi Chemical Group Corp.)
• Original Assignee: Mitshubishi Chemcial
• Inventors: Kijima, Naoto, Shimizu, Etsuo, Yoshino, Masahiko
• Application Number:
  US11/816,920
• Publication Number:
  US 20090008663A1
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: C09K 11/7774 Aluminates
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48257 connecting the wire to a die pad of the item
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 33/502 Wavelength conversion materials

Abstract

A phosphor containing a crystal phase having a chemical composition expressed by the following general formula [1], and exhibiting an average variation rate of the emission intensity of 1.3 or less upon excitation with light having a peak in the wavelength range of 420 nm to 480 nm, the variation rate of the emission intensity being calculated by the following general formula [2].

(Ln_1-a-bCe_aTb_b)₃M₅O₁₂  [1]

• • wherein Ln is at least one element selected from the group consisting of Y, Gd, Sc, Lu, and La, M represents at least one element selected from the group consisting of Al, Ga, and In, and a and b satisfy 0.001≦a≦0.3 and 0≦b≦0.5, respectively.

Variation rate of emission intensity=[(I(λ+1)−I(λ))/I(λ)]²  [2]

• • wherein I(λ) is the emission intensity of the phosphor at an excitation wavelength of λnm, and I(λ+1) is the emission intensity of the phosphor at an excitation wavelength of (λ+1) nm.

Claims

1. A phosphor comprising a crystal phase having a chemical composition expressed by the following general formula [1], and providing an average variation rate of the emission intensity of 1.3 or less upon excitation with light having a peak in the wavelength range of 420 nm to 480 nm, the variation rate of the emission intensity being calculated by the following general formula [2]:

(Ln_1-a-bCe_aTb_b)₃M₅O₁₂ 

 

[1]

wherein Ln is at least one element selected from the group consisting of Y, Gd, Sc, Lu, and La, M represents at least one element selected from the group consisting of Al, Ga, and In, and a and b satisfy 0.001≦

a≦

0.3 and 0≦

b≦

0.5, respectively.

Variation rate of emission intensity=[(I(λ

+1)−

I(λ

)/I(λ

)]² 

 

[2]

wherein I(λ

) is the emission intensity of the phosphor at an excitation wavelength of λ

nm, and I(λ

+1) is the emission intensity of the phosphor at an excitation wavelength of (λ

+1) nm.

2. The phosphor according to claim 1, wherein the average variation rate of the emission intensity is 1.1 or less.

3. The phosphor according to claim 1, wherein the weight-average median diameter D₅₀ is 10 μ

m or more.

4. The phosphor according to claim 1, wherein the weight-average median diameter D₅₀ is 14 μ

m or more.

5. The phosphor according to claim 1, which comprises at least Y as Ln in the general formula [1], and at least Al as M in the general formula [1].

6. The phosphor according to claim 1, wherein the values a and b in the general formula [1] satisfy 0.02≦

a≦

0.15, and 0.02<

b≦

0.5, respectively.

7. The phosphor according to claim 5, which comprises at least Y and Lu as Ln in the general formula [1].

8. The phosphor according to claim 7, wherein the Lu content is from 0.03 to 1. The Lu content corresponds to q when the general formula [1] is expressed by the following general formula [1A]:

Y_pLu_qCe^3aTb_3bM₅O₁₂ 

 

[1A]

wherein in the general formula [1A], M, a, and b are the same as those in the general formula [1], p and q represent the Y content and Lu content, respectively, and Y_pLu_q=Ln_3-3a-3b.

9. The phosphor according to claim 5, which comprises at least Al and Ga as M in the general formula [1].

10. The phosphor according to claim 9, wherein the Ga content is from 0.2 to 3, the Ga content corresponding to r when the general formula [1] is expressed by the following general formula [1B]:

(Ln_1-a-bCe_aTb_b)₃M′

_5-rGa_rO₁₂ 

 

[1B]

wherein in the general formula [1B], Ln, a, and b are the same as those in the general formula [1], M′

represents M other than Ga (M is the same as that in the general formula [1]), and M′

_5-rGa_r=M₅.

11. The phosphor according to claim 1, wherein the average circularity is 0.86 or more.

12. The phosphor according to claim 1, wherein the object color satisfies L*≧

90, a*≦

−

7, and b*≧

55 under a color system of L*, a*, and b*.

15. A method for producing a phosphor according to claim 1, comprising mixing raw materials containing constituent elements, and then firing the mixture, wherein the molar ratio between the charged raw materials satisfies (5/3)<

(M/(Ln_1-a-bCe_aTb_b), and the fired product obtained by firing is subjected to washing with acid.

16. The method for producing a phosphor according to claim 15, wherein at least Al is contained as M in the general formula [1], and α

-alumina is used as the Al source.

19. A phosphor-containing composition comprising the phosphor according to claim 1 and a liquid medium.

20. A light-emitting device comprising a first light emitter which emits light ranging from the ultraviolet to visible region, and a second light emitter which converts the wavelength of at least a portion of light emitted from the first light emitter to emit light in a longer wavelength range than that of the light emitted by the first light emitter, wherein the second light emitter comprises the phosphor according to claim 1.

21. The light-emitting device according to claim 20, wherein the first light emitter is a laser diode or a light-emitting diode.

22. An image display device comprising the light-emitting device according to claim 20 as a light source.

23. A lighting system comprising the light-emitting device according to claim 20 as a light source.

13. A phosphor which has an object color satisfying L*≧

90, a*≦

−

7, and b*≧

55 under a color system of L*, a*, and b*, comprises a crystal phase having a chemical composition expressed by the following general formula [1], and has a median diameter D₅₀ of 15 μ

m or more;

(Ln_1-a-bCe_aTb_b)₃M₅O₁₂ 

 

[1]

wherein Ln is at least one element selected from the group consisting of Y, Gd, Sc, Lu, and La, M represents at least one element selected from the group consisting of Al, Ga, and In, and a and b satisfy 0.001≦

a≦

0.3 and 0≦

b≦

0.5, respectively.

14. The phosphor according to claim 13, wherein the average circularity is 0.86 or more.

17. A method for producing the phosphor according to claim 13, comprising raw materials containing constituent elements, and then firing the mixture, wherein the molar ratio between the charged raw materials satisfies (5/3)<

(M/(Ln_1-a-bCe_aTb_b), and the fired product obtained by firing is subjected to washing with acid.

18. The method for producing a phosphor according to claim 17, wherein at least Al is contained as M in the general formula [1], and α

-alumina is used as the raw material of Al.