Light emitting device using fluorescent substance

• US 20050179364A1
• Filed: 04/25/2002
• Published: 08/18/2005
• Est. Priority Date: 04/25/2002
• Status: Active Grant

• Current Assignee: Nichia Corporation
• Original Assignee: Nichia Corporation
• Inventors: Murazaki, Yoshinori
• Granted Patent: US 7,432,642 B2
• Time in Patent Office: Days
• US Class Current: 313/498
• CPC Class Codes: C09K 11/0883 Arsenides; Nitrides; Phosphides
• CPC Class Codes: C09K 11/7739 with halogens
• CPC Class Codes: C09K 11/774 Borates
• CPC Class Codes: C09K 11/7789 Oxysulfides
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45139 Silver (Ag) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/8592 Applying permanent coating, e.g. protective coating
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• 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 2924/207 Diameter ranges
• CPC Class Codes: H01L 33/502 Wavelength conversion materials
• CPC Class Codes: H01L 33/504 Elements with two or more 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

Abstract

A light emitting device related to the present invention, which has a semiconductor light emitting element and a phosphor which converts a part of the luminescence spectrum emitted from the semiconductor light emitting element, characterized in that the luminescence spectrum of the semiconductor light emitting element is located between a near ultraviolet region and a short-wavelength visible region, and the phosphor is made by adding a red luminescent activator to a base material of a blue luminescent phosphor, thereby improving the color shading generated by the dispersion of the spectra of the light emitting elements and obtaining the light emitting device having a high brightness and a good color rendering properties. With this, it is possible to provide the light sources for the lighting apparatus of medical treatments, the flash plate of a copying machine, etc., in which a good color rendering property is required.

Claims

1-10. -10. (canceled)

11. A light emitting device comprising a semiconductor light emitting element and a phosphor which converts a part of a luminescence spectrum emitted from the semiconductor light emitting element;

wherein said luminescence spectrum of said semiconductor light emitting element is located between a near ultraviolet region and a short-wavelength visible region,

wherein said phosphor is made by adding a red luminescent activator to a base material of a blue luminescent phosphor.

12. The light emitting device according to claim 11;

wherein the emission wavelength can be adjusted by the added ratio of said red luminescent activator.

13. The light emitting device according to claims 11;

wherein said semiconductor light emitting element has a main peak wavelength more than 360 nm in the ultraviolet region.

14. The light emitting element according to claim 11;

wherein said phosphor is an alkaline earth metal boric halide phosphor activated by at least Mn and Eu.

15. The light emitting element according to claim 11;

wherein said phosphor is represented by a general formula of

(M_1-x-yEu_xM′

_y)₂B₅O₉M″

,

where M is at least one selected from the group consisting of Mg, Ca, Ba, Sr, M′

is at least one selected from the group consisting of Mn, Fe, Cr, Sn, 0.0001≦

x≦

0.5, 0.0001≦

y≦

0.5, and M″

is at least one halogen selected from the group consisting of F, Cl, Br, I.

16. The light emitting device as in one of claim 11;

further comprising a phosphor selected from the group consisting of

an alkaline earth halogen apatite phosphor activated by Eu, or Eu and Mn [(Sr, Ca, Ba, Mg, Zn)₅(PO₄)₃(F, Cl, Br, I);

Eu, Mn],

an alkaline earth metal aluminate phosphor [SrAl₂O₄;

Eu, Sr₄Al₁₄O₂₅;

Eu(Mn), CaAl₂O₄;

Eu(Mn), BaMg₂Al₁₆O₂₇;

Eu, BaMg₂Al₁₆O₁₂;

Eu,Mn, BaMgAl₁₀O₁₇;

Eu(Mn)],

a phosphor of CaO—

Al₂O₃—

SiO₂ including nitride activated by Eu and/or Cr [oxynitride fluoroglass],

a phosphor of M_xSi_yN_z;

Eu (where M is at least one selected from the group consisting of Mg, Ca, Ba, Sr, Zn, z=⅔

x+ 4/3y),

an yttrium aluminate phosphor activated by cerium,

a rare earth acid sulfide phosphor activated by Eu (La₂O₂S;

Eu, Y₂O₂S;

Eu and Gd₂O₂S;

Eu),

an organic complex phosphor activated by Eu [(Sr, Ca, Ba, Mg)₅(PO₄)₃Cl;

Eu, ZnS;

Cu, Zn₂GeO₄;

Mn, (Sr, Ca, Ba, Mg)Ga₂S₄;

Eu and (Sr, Ca, Ba, Mg)₂Si₅N;

Eu].

17. A light emitting device comprising a semiconductor light emitting element and a phosphor which converts a part of a luminescence spectrum emitted from the semiconductor light emitting element;

wherein said luminescence spectrum of said semiconductor light emitting element is located between a near ultraviolet region and a short-wavelength visible region,

wherein said phosphor is an alkaline earth metal boric halide phosphor including at least one element represented by M selected from the group consisting of Mg, Ca, Ba, Sr and at least one element represented by M′

selected from the group consisting of Mn, Fe, Cr, Sn.

18. The light emitting element according to claim 17;

wherein the light emitting layer of said semiconductor light emitting element is made of a nitride semiconductor including at least In and Ga.

19. The light emitting element according to claim 17;

wherein the light emitting layer of said semiconductor light emitting element is made of a nitride semiconductor including at least Ga and Al.

20. The light emitting element according to claim 17;

wherein said phosphor is an alkaline earth metal boric halide phosphor activated by at least Mn and Eu.

21. The light emitting element according to claim 17;

wherein said phosphor is represented by a general formula of

(M_1-x-yEu_xM′

_y)₂B₅O₉M″

,

where M is at least one selected from the group consisting of Mg, Ca, Ba, Sr, M′

is at least one selected from the group consisting of Mn, Fe, Cr, Sn, 0.0001≦

x≦

0.5, 0.0001≦

y≦

0.5, and M″

is at least one halogen selected from the group consisting of F, Cl, Br, I.

22. The light emitting device according to claim 17;

further comprising a phosphor selected from the group consisting of

an alkaline earth halogen apatite phosphor activated by Eu, or Eu and Mn [(Sr, Ca, Ba, Mg, Zn)₅(PO₄)₃(F, Cl, Br, I);

Eu, Mn],

an alkaline earth metal aluminate phosphor [SrAl₂O₄;

Eu, Sr₄Al₁₄O₂₅;

Eu(Mn), CaAl₂O₄;

Eu(Mn), BaMg₂Al₁₆O₂₇;

Eu, BaMg₂Al₁₆O₁₂;

Eu,Mn, BaMgAl₁₀O₁₇;

Eu(Mn)],

a phosphor of CaO—

Al₂O₃—

SiO₂ including nitride activated by Eu and/or Cr [oxynitride fluoroglass],

a phosphor of M_xSi_yN_z;

Eu (where M is at least one selected from the group consisting of Mg, Ca, Ba, Sr, Zn, z=⅔

x+ 4/3y),

an yttrium aluminate phosphor activated by cerium,

a rare earth acid sulfide phosphor activated by Eu (La₂O₂S;

Eu, Y₂O₂S;

Eu and Gd₂O₂S Eu),

an organic complex phosphor activated by Eu [(Sr, Ca, Ba, Mg)₅(PO₄)₃Cl;

Eu, ZnS;

Cu, Zn₂GeO₄;

Mn, (Sr, Ca, Ba, Mg)Ga₂S₄;

Eu and (Sr, Ca, Ba, Mg)₂Si₅N;

Eu].

23. A light emitting device comprising;

a semiconductor light emitting element of which luminescence spectrum is located between a near ultraviolet region and a short-wavelength visible region,

a first phosphor which converts a part of a luminescence spectrum emitted from the semiconductor light emitting element, said first phosphor being made by adding an activator for red light emission to a base material of a blue emitting phosphor,

a second phosphor which can convert a part of the light emitted from the first phosphor to a light having a wavelength in a range from blue region to red region,

wherein a mixed light of the light emitted from the first phosphor and the light emitted from the second phosphor is outputted, said mixed light having a wavelength within a range of white region.

24. The light emitting device according to claim 23;

further comprising a phosphor selected from the group consisting of

an alkaline earth halogen apatite phosphor activated by Eu, or Eu and Mn [(Sr, Ca, Ba, Mg, Zn)₅(PO₄)₃(F, Cl, Br, I);

Eu, Mn],

an alkaline earth metal aluminate phosphor [SrAl₂O₄;

Eu, Sr₄Al₁₄O₂₅;

Eu(Mn), CaAl₂O₄;

Eu(Mn), BaMg₂Al₁₆O₂₇;

Eu, BaMg₂A₁₆O₂₇;

Eu,Mn, BaMgAl₁₀O₁₇;

Eu(Mn)],

a phosphor of CaO—

Al₂O₃—

SiO₂ including nitride activated by Eu and/or Cr [oxynitride fluoroglass],

a phosphor of M_xSi_yN_z;

Eu (where M is at least one selected from the group consisting of Mg, Ca, Ba, Sr, Zn, z=⅔

x+ 4/3y),

an yttrium aluminate phosphor activated by cerium,

a rare earth acid sulfide phosphor activated by Eu (La₂O₂S;

Eu, Y₂O₂S;

Eu and Gd₂O₂S;

Eu),

an organic complex phosphor activated by Eu [(Sr, Ca, Ba, Mg)₅(PO₄)₃Cl;

Eu, ZnS;

Cu, Zn₂GeO₄;

Mn, (Sr, Ca, Ba, Mg)Ga₂S₄;

Eu and (Sr, Ca, Ba, Mg)₂Si₅N;

Eu].