Phosphor for electron beam excitation and color display device using the same

• US RE45,640 E1
• Filed: 03/09/2012
• Issued: 08/04/2015
• Est. Priority Date: 08/02/2004
• Status: Active Grant

• Current Assignee: Citizen Electronics Company Limited, Nichia Corporation
• Original Assignee: Dowa Electronics Materials Co. Ltd. (DOWA Holdings Company Limited), Nichia Corporation
• Inventors: Gotoh, Masahiro, Nagatomi, Akira, Sakane, Kenji, Yamashita, Shuji
• Primary Examiner(s): Patel, Nimeshkumar
• Assistant Examiner(s): RAABE, CHRISTOPHER M
• Application Number:
  US13/417,146
• Time in Patent Office: 1,243 Days
• Field of Search: 313/467, 313/468, 252/301.4 R, 252/301.6 R, 252/301.4 F, 252/301.6 F
• US Class Current: 1/1
• CPC Class Codes: C04B 2235/3224 Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
• CPC Class Codes: C04B 2235/3852 Nitrides, e.g. oxynitrides, carbonitrides, oxycarbonitrides, lithium nitride, magnesium nitride
• CPC Class Codes: C04B 2235/3865 Aluminium nitrides
• CPC Class Codes: C04B 2235/3873 Silicon nitrides, e.g. silicon carbonitride, silicon oxynitride
• CPC Class Codes: C04B 2235/5436 micrometer sized, i.e. from 1 to 100 micron
• CPC Class Codes: C04B 35/581 based on aluminium nitride
• CPC Class Codes: C04B 35/584 based on silicon nitride
• CPC Class Codes: C04B 35/6262 of calcined, sintered clinker or ceramics
• CPC Class Codes: C09K 11/7734 Aluminates
• CPC Class Codes: C09K 11/7787 Oxides C09K11/7785 takes precedence
• CPC Class Codes: H01J 29/20 characterised by the luminescent material

Abstract

A phosphor, which has less reduction in emission efficiency and is capable of keeping high luminance even when density of an electron beam for exciting the phosphor increases, is provided. As raw materials, Ca₃N₂ (2N), AlN (3N), Si₃N₄ (3N), and Eu₂O₃ (3N) are prepared, and each of the raw materials is weighed so that a mole ratio of each element is, for example, (Ca+Eu):Al:Si=1:1:1, and mixed, then the mixture is held and fired at 1500° C. under the inert atmosphere for three hours, and thereafter ground to produce a phosphor having a composition formula of Ca_0.985SiAlN₃:Eu_0.015.

Claims

1. A phosphor for electron beam excitation expressed by a composition formula of MmAaBbOoNn:

Z (where an element M is one or more bivalent elements, an element A is one or more trivalent elements, an element B is one or more tetravalent elements, O is oxygen, N is nitrogen, an element Z is an activator, and where values of m=a=b=1, o≧

0, and n=2/3m+a+4/3b−

2/3o).

2. The phosphor for electron beam excitation according to claim 1, wherein the element M is one or more elements selected from Mg (magnesium), Ca (calcium), Sr (strontium), Ba (barium) and Zn (zinc), the element A is one or more elements selected from B (boron), Al (aluminum) and Ga (gallium), the element B is Si (silicon) and/or Ge (germanium), and the element Z is one or more elements selected from rare earth or transition metals.

3. The phosphor for electron beam excitation according to claim 1, wherein the element A is Al (aluminum), and the element B is Si (silicon).

4. The phosphor for electron beam excitation according to claim 1, wherein the element M is Ca (calcium) and the element Z is Eu (europium).

5. The phosphor for electron beam excitation according to claim 1, wherein said phosphor for electron beam excitation is expressed by a general formula of CaAlSiN₃:

Eu.

6. The phosphor according to claim 1, wherein said phosphor for electron beam excitation is in a powder form.

7. The phosphor for electron beam excitation according to claim 6, wherein an average particle size of said phosphor for electron beam excitation is from 1 μ

m to 10 μ

m inclusive.

8. A color display device, wherein the phosphor for electron beam excitation according to claim 1 is used.

9. A method of exciting a phosphor to emit light by electron beam irradiation, comprising:

providing a phosphor expressed by a composition formula of MmAaBbOoNn;

Z, where an element M is one or more bivalent elements, an element A is one or more trivalent elements, an element B is one or more tetravalent elements, O is oxygen, N is nitrogen, and an element Z is an activator, and where values of m>

0, a>

0, b>

0, o≧

0, where values of m=a=b=1, and n=2/3m+a+4/3b−

2/3o); and

irradiating the phosphor with an electron beam.

10. The method of claim 9, wherein the element M is one or more elements selected from Mg (magnesium), Ca (calcium), Sr (strontium), Ba (barium) and Zn (zinc), the element A is one or more elements selected from B (boron), Al (aluminum) and Ga (gallium), the element B is Si (silicon) and/or Ge (germanium), and the element Z is one or more elements selected from rare earth or transition metals.

11. The method of claim 9, wherein the element A is Al (aluminum), and the element B is Si (silicon).

12. The method of claim 9, wherein the element M is Ca (calcium) and the element Z is Eu (europium).

13. The method of claim 9, wherein said phosphor for electron beam excitation is expressed by a general formula of CaAlSiN₃:

Eu.

14. The method of claim 9, wherein said phosphor is in a powder form.

15. The method of claim 14, wherein an average particle size of said phosphor for electron beam excitation is from 1 μ

m to 10 μ

m inclusive.