SURFACE-TREATED FLUORESCENT MATERIAL AND PROCESS FOR PRODUCING SURFACE-TREATED FLUORESCENT MATERIAL

• US 20130161678A1
• Filed: 08/04/2011
• Published: 06/27/2013
• Est. Priority Date: 08/04/2010
• Status: Active Grant

• Current Assignee: Sekisui Chemical Company Limited (Sekisui)
• Original Assignee: Ren-De Sun
• Inventors: Sun, Ren-de, Nakatani, Yasuhiro, Oomura, Takahiro
• Granted Patent: US 8,791,488 B2
• Time in Patent Office: Days
• US Class Current: 257/98
• CPC Class Codes: C09K 11/025 non-luminescent particle coatings or suspension media
• CPC Class Codes: C09K 11/77342 Silicates
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• 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
• CPC Class Codes: Y10T 428/2991 Coated
• CPC Class Codes: Y10T 428/2993 Silicic or refractory material containing [e.g., tungsten oxide, glass, cement, etc.]

Abstract

Provided are a surface treated phosphor having high dispersibility and remarkably improved moisture resistance without degradation in fluorescence properties, and a method of producing the surface treated phosphor.

The present invention relates to a surface treated phosphor including: a phosphor matrix including an alkaline earth metal and silicon; and a surface treatment layer including an alkaline earth metal, silicon, and a specific element belonging to groups 4 to 6 of the periodic table, wherein, when element distribution of the surface treatment layer in the thickness direction viewed in cross-section is determined by electron microscopy and energy dispersive X-ray spectroscopy coupled with the electron microscopy, the position representing the maximum peak of a specific element content is located closer to the surface than the position representing the maximum peak of a silicon content and silicon contents of the phosphor matrix and the surface treatment layer satisfy the following formula (1):

[Formula 1]

S₁<S₂  (1)

• • wherein S₁ represents the silicon content of the phosphor matrix and S₂ represents the silicon content of the surface treatment layer.

Claims

1. A surface treated phosphor comprising:

a phosphor matrix including an alkaline earth metal and silicon; and

a surface treatment layer including an alkaline earth metal, silicon, and a specific element belonging to groups 4 to 6 of the periodic table,

wherein, when element distribution of the surface treatment layer in the thickness direction viewed in cross-section is determined by electron microscopy and energy dispersive X-ray spectroscopy coupled with the electron microscopy, the position representing the maximum peak of a specific element content is located closer to the surface than the position representing the maximum peak of a silicon content and

silicon contents of the phosphor matrix and the surface treatment layer satisfy the following formula (1);

[Formula 1]

S₁<

S₂ 

 

(1)

wherein S₁ represents the silicon content of the phosphor matrix and S₂ represents the silicon content of the surface treatment layer.

2. The surface treated phosphor according to claim 1,

wherein, in the element distribution of the surface treatment layer in the thickness direction viewed in cross-section, silicon is detected at the position representing the maximum peak of the specific element.

3. The surface treated phosphor according to claim 1,

wherein the surface treatment layer includes an intermediate layer and a surface layer formed in the noted order from inside toward the outermost surface, and an alkaline earth metal content of each layer satisfies the following formulae (2) and (3):

[Formula 2]

C₂<

C₁ 

 

(2)

C₂<

C₃ 

 

(3)

wherein C₁ represents the alkaline earth metal content of the phosphor matrix, C₂ represents the alkaline earth metal content of the intermediate layer, and C₃ represents the alkaline earth metal content of the surface layer.

4. The surface treated phosphor according to claim 3,

wherein C₂ is ⅔

or less of C₁.

5. The surface treated phosphor according to claim 1,

wherein an alkaline earth metal present in the surface treatment layer is an alkaline earth metal derived from the phosphor matrix.

6. The surface treated phosphor according to claim 1,

wherein the phosphor matrix comprises a silicate phosphor that contains an alkaline earth metal.

7. The surface treated phosphor according to claim 6,

wherein the phosphor matrix comprises a silicate phosphor represented by the following formula (4):

(Sr_1-xM_x)_ySiO₄;

Eu²⁺ 

 

(4)

wherein M is at least one metal selected from the group consisting of Ba, Ca, Mg, and Zn.

8. The surface treated phosphor according to claim 6,

wherein the phosphor matrix comprises a silicate phosphor represented by the following formula (5):

(Sr_1-xM_x)_ySiO₄;

Eu²⁺D 

 

(5)

wherein M is at least one metal selected from the group consisting of Ba, Ca, Mg, and Zn, and D is an anion of a halogen selected from the group consisting of F, Cl, and Br.

9. The surface treated phosphor according to claim 1,

wherein an electric conductivity of water is 100 mS/m or lower when 1 part by weight of the surface treated phosphor is immersed in 300 parts by weight of pure water for 10 minutes.

10. A phosphor-containing resin composition comprising:

the surface treated phosphor according to claim 1; and

an epoxy resin and/or a silicone resin.

11. A wavelength converting composite comprising:

at least one resin selected from the group consisting of resins of polyvinyl acetate, polyvinyl butyral, polyethylene, polypropylene, polymethylmethacrylate, polycarbonate, and a cyclic olefin copolymer; and

the surface treated phosphor according to claim 1, dispersed in the at least one resin.

12. A wavelength converting sheet being a sheet of the wavelength converting composite according to claim 11.

13. A photoelectric converter comprising:

the wavelength converting composite according to claim 11 as a component.

14. A semiconductor light-emitting element comprising:

the surface treated phosphor according to claim 1.

15. An LED device comprising:

an LED chip;

a resin flame surrounding the LED chip; and

a layer of a phosphor filling a concave portion defined by the resin flame,

wherein the layer of a phosphor includes the surface treated phosphor according to claim 1 and an sealing resin.

16. The LED device according to claim 15,

wherein the device keeps retention of brightness of 80% or higher after it is aged for 72 hours under conditions at a temperature of 121°

C. and a relative humidity of 100%.

17. A backlight for liquid crystal display element comprising:

the LED device according to claim 15 as a component.

18. An image display device comprising:

the LED device according to claim 15 as a component.

19. A lighting equipment comprising:

the LED device according to claim 15 as a component.

20. A method of producing the surface treated phosphor according to claim 1, comprising:

forming a surface treatment layer by dispersing a phosphor matrix in a solution that includes a complex ion containing a specific element and fluorine to bring the phosphor matrix into contact with the solution.

21. The method according to claim 20,

wherein the complex ion containing a specific element and fluorine is AF₆²⁻

,

wherein A is at least one specific element selected from the group consisting of elements belonging to groups 4 to 6 of the periodic table.

22. The method according to claim 20,

wherein a boric acid is further added during the formation of the surface treatment layer.