Phosphor and manufacturing method for the same, and light source

• US 7,476,337 B2
• Filed: 07/15/2005
• Issued: 01/13/2009
• Est. Priority Date: 07/28/2004
• Status: Active Grant

• Current Assignee: Citizen Electronics Company Limited
• Original Assignee: Dowa Electronics Materials Co. Ltd. (DOWA Holdings Company Limited), Nichia Corporation
• Inventors: Gotoh, Masahiro, Nagatomi, Akira, Yamashita, Shuji, Sakane, Kenji
• Primary Examiner(s): KOSLOW, CAROL M
• Application Number:
  US11/182,190
• Publication Number:
  US 20060033083A1
• Time in Patent Office: 1,278 Days
• Field of Search: 2523014 R-3016 R
• US Class Current: 252/301.40F
• CPC Class Codes: C09K 11/0883 Arsenides; Nitrides; Phosphides
• CPC Class Codes: C09K 11/77348 Silicon Aluminium Nitrides or Silicon Aluminium Oxynitrides
• CPC Class Codes: H05B 33/14 characterised by the chemical or physical composition or the arrangement of the electroluminescent material , or by the simultaneous addition of the electroluminescent material in or onto the light source

Abstract

To provide a phosphor having an emission characteristic such that a peak wavelength of light emission is in a range from 580 to 680 nm, and having a high emission intensity, and having a flat excitation band with high efficiency for excitation light in a broad wavelength range from ultraviolet to visible light (wavelength range from 250 nm to 550 nm). For example, Ca₃N₂(2N), AlN(3N), Si₃N₄(3N), Eu₂O₃(3N) are prepared, and after weighing and mixing a predetermined amount of each raw material, raw materials are fired at 1500° C. for 6 hours, thus obtaining the phosphor including a product phase expressed by a composition formula CaAlSiN₃:Eu and having an X-ray diffraction pattern satisfying a predetermined pattern.

Claims

1. A manufacturing method of a phosphor, with the product phase expressed by a composition formula MABOoNn:

Z, where element M is at least one kind of element having bivalent valency, element A is at least one kind of element having tervalent valency, element B is at least one kind of element selected from the elements having tetravalent valency, O is oxygen, N is nitrogen, and element Z is at least one kind of element selected from rare earth elements or transitional metal elements, satisfying n=3−

2/3o, o+n>

8/3, said manufacturing method comprising;

obtaining a mixture by weighing and mixing raw material powders of this phosphor under an inert atmosphere;

maintaining and firing the mixture for 0.5 hours or more at 1000°

C. or more to obtain a fired product; and

pulverizing the obtained fired product to obtain a phosphor having a prescribed average particle size,

wherein in the step of obtaining the fired product by firing the mixture, any one of nitrogen, ammonia, mixed gas of ammonia and nitrogen, or mixed gas of nitrogen and hydrogen is used as the atmosphere gas during firing, and

firing is performed while 0.01 L/min or more of the atmosphere gas in the firing furnace is ventilated.

2. The manufacturing method of the phosphor according to claim 1, satisfying n=3, o=0.

3. The manufacturing method of the phosphor according to claim 1, wherein the element M is at least one kind of element selected from the group consisting of Mg, Ca, Sr, Ba, and Zn, and the element A is at least one kind of element selected from the group consisting of B(boron), Al, and Ga, the element B is Si and/or Ge, and the element Z is at least one kind of element selected from rare earths or transitional metals.

4. The manufacturing method of the phosphor according to claim 1, wherein

the element M is at least one kind of element having bivalent valency, indispensably including Ca;

the element A is at least one kind of element having tervalent valency, indispensably including Al; and

the element B is at least one kind of element having tetravalent valency, indispensably including Si.

5. The manufacturing method of the phosphor according to claim 1, wherein the element M is Ca, the element A is Al, the element B is Si, and the element Z is Eu.

6. The manufacturing method of the phosphor according to claim 1, wherein the phosphor having a wavelength of a maximum peak in an emission spectrum set to be 650 nm or more, when the phosphor is irradiated with more than one kind of monochromatic lights in a wavelength range from 250 nm to 550 nm or continuous light including this wavelength range as an excitation light.

7. The manufacturing method of the phosphor according to claim 1, wherein the phosphor having a size (Dx) of a crystallite of the phosphor particle set to be 50 nm or more.

8. The manufacturing method of the phosphor according to claim 1, wherein the phosphor having a unit volume of a crystal lattice of the product phase included in the phosphor set to be 275 Å

³ or more.

9. The manufacturing method of the phosphor according to claim 1, wherein the phosphor having a lattice constant of the crystal lattice of the product phase included in the phosphor set to be a=9.75 Å

or more, b=5.64 Å

or more, and c=5.05 Å

or more.

10. The manufacturing method of the phosphor according to claim 1, wherein the gas containing 80% or more of nitrogen gas is used as the atmosphere gas in the firing furnace during firing.

11. The manufacturing method of the phosphor according to claim 1, wherein

the element M is at least one kind of element having bivalent valency, indispensably including Ca;

the element A is at least one kind of element having tervalent valency, indispensably including Al; and

the element B is at least one kind of element having tetravalent valency, indispensably including Si.

13. The manufacturing method of the phosphor according to claim 4, wherein the phosphor comprises a phase showing a diffraction peak with relative intensity of 10% or more in the Bragg angle (2θ

) range from 36.5°

to 37.5° and

from 41.9°

to 42.9°

of the X-ray diffraction pattern as a main product phase, when the relative intensity of the diffraction peak having a highest intensity in a powder X-ray diffraction pattern by CoKα

ray is defined as 100%.

14. The manufacturing method of the phosphor according to claim 4, wherein the phosphor comprises a phase showing a diffraction peak with relative intensity of 10% or more in the Bragg angle (2θ

) range from 36.5°

to 37.5° and

from 40.9°

to 41.9°

, 41.9°

to 42.9°

, 56.3°

to 57.3°

, 66.0°

to 67.0°

, 75.8°

to 76.8°

, and 81.0°

to 83.0°

of the X-ray diffraction pattern, when the relative intensity of the diffraction peak having a highest intensity in a powder X-ray diffraction pattern by CoKα

ray is defined as 100%.

12. A manufacturing method of a phosphor, with the product phase expressed by a composition formula MABOoNn:

Z, where element M is at least more than one kind of element having bivalent valency, element A is at least one kind of element having tervalent valency, element B is at least one kind of element selected from the elements having tetravalent valency, O is oxygen, N is nitrogen, and element Z is at least one kind of element selected from rare earth elements or transitional metal elements, satisfying n=3−

2/3o, o+n>

8/3, said manufacturing method comprising;

obtaining a mixture by weighing and mixing raw material powders of this phosphor under an inert atmosphere;

maintaining and firing the mixture for 0.5 hours or more at 1000°

C. or more to obtain a fired product; and

pulverizing the obtained fired product to obtain a phosphor having a prescribed average particle size,

wherein in the step of obtaining the fired product by firing the mixture, any one of nitrogen, ammonia, mixed gas of ammonia and nitrogen, or mixed gas of nitrogen and hydrogen is used as the atmosphere gas during firing, and

firing is performed while 0.01 L/min or more of the atmosphere gas in the firing furnace is ventilated,

with the atmosphere gas in the firing furnace set in a pressurized state of 0.001 MPa or more and 0.1 MPa or less.