Phosphor and manufacturing method for the same, and light source

• US 20060033083A1
• Filed: 07/15/2005
• Published: 02/16/2006
• Est. Priority Date: 07/28/2004
• Status: Active Grant

• Current Assignee: Citizen Electronics Company Limited
• Original Assignee: Dowa Mining Company Limited
• Inventors: Gotoh, Masahiro, Nagatomi, Akira, Yamashita, Shuji, Sakane, Kenji
• Granted Patent: US 7,476,337 B2
• Time in Patent Office: Days
• 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 phosphor, comprising 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%.

4. The phosphor according to claim 1, wherein a crystal system of the product phase is an orthorhombic system.

5. The phosphor according to claim 1, wherein the product phase is expressed by a composition formula MmAaBbOoNn:

Z, where element M is at least more than one kind of element having bivalent valency, element A is at least more than one kind of element having tervalent valency, element B is at least more than one kind of element selected from the elements having tetravalent valency, O is oxygen, N is nitrogen, and element Z is at least more than one kind of element selected from rare earth elements or transitional metal elements, satisfying n=2/3m+a+4/3b−

2/3o, m/(a+b)≧

1/2, (o+n)/(a+b)>

4/3, o≧

0, and m;

a;

b=1;

1;

1.

6. The phosphor according to claim 1, wherein the product phase is expressed by a composition formula MmAaBbNn:

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

a;

b;

n=1;

1;

1;

3.

7. The phosphor according to claim 5, wherein the element M is at least more than one kind of element selected from the group consisting of Mg, Ca, Sr, Ba, and Zn, and the element A is Al, the element B is Si, and the element Z is at least more than one kind of element selected from Eu, Mn, and Ce.

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

9. The phosphor according to claim 1, wherein no diffraction peak with relative intensity of beyond 5% exists in the Bragg angle (2θ

) range from 38.0°

to 40.0°

of the X-ray diffraction pattern, when the powder X-ray diffraction pattern of the phosphor by CoKα

ray is measured, and the relative intensity of the diffraction peak with highest intensity in the X-ray diffraction pattern is defined as 100%.

10. The phosphor according to claim 5, wherein a wavelength of a maximum peak in an emission spectrum is 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.

11. The phosphor according to claim 5, wherein the size (Dx) of a crystallite of the phosphor particle is 50 nm or more.

12. The phosphor according to claim 5, wherein a unit volume of a crystal lattice of the product phase included in the phosphor is 275 Å

³ or more.

13. The phosphor according to claim 5, wherein a lattice constant of the crystal lattice of the product phase included in the phosphor is a=9.75 Å

or more, b=5.64 Å

or more, and c=5.05 Å

or more.

14. A manufacturing method of the phosphor according to claim 1, comprising the steps of:

obtaining a mixture by weighing and mixing raw material powders of the phosphor;

obtaining a fired material by firing the mixture in a firing furnace; and

obtaining the phosphor by pulverizing the fired material,

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

15. The manufacturing method of the phosphor according to claim 14, wherein the gas containing 80% or more of nitrogen gas is used as the atmosphere gas in the firing furnace during firing.

16. The manufacturing method of the phosphor according to claim 14, wherein in the step of obtaining the fired material by firing the mixture in the firing furnace, the mixture is fired, while 0.01 L/min or more of atmosphere gas is ventilated in the firing furnace during firing.

17. The manufacturing method of the phosphor according to claim 14, wherein in the step of obtaining the fired material by firing the mixture in the firing furnace, the pressure of atmosphere gas is set at 0.001 MPa or more and 0.1 MPa or less to make the inside the firing furnace in a pressurized state.

18. A light source using the phosphor according to claim 1

2. A phosphor, comprising 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°

, and from 56.3°

to 57.3°

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%.

3. A phosphor, comprising 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°

, 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%.