RED FLUORESCENT SUBSTANCE AND LIGHT-EMITTING DEVICE EMPLOYING THE SAME

• US 20100102707A1
• Filed: 10/27/2009
• Published: 04/29/2010
• Est. Priority Date: 10/29/2008
• Status: Abandoned Application

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: MATSUDA, Naotoshi, FUKUDA, Yumi
• Application Number:
  US12/606,279
• Publication Number:
  US 20100102707A1
• Time in Patent Office: Days
• US Class Current: 313/503
• 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: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• 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

Abstract

The present invention provides a red fluorescent substance and a light-emitting device utilizing the substance. This device less suffers from color drift even when working with high power. The light-emitting device comprises a blue LED, a green fluorescent substance of Sr₃Al₃Si₁₃O₂N₂₁ activated with a luminescent center, and the red fluorescent substance. The red fluorescent substance contains an inorganic compound comprising a metal element M, a trivalent element M¹ other than the M, a tetravalent element M² other than the M, and nitrogen element. In the inorganic compound, the M is partly replaced with a luminescent center element EC. The red fluorescent substance has basically the same crystal structure as Sr₂Al₃Si₇ON₁₃. The red fluorescent substance emits luminescence having a peak in the range of 580 to 650 nm when excited with light of 250 to 500 nm.

Claims

1. A fluorescent substance comprising an inorganic compound which comprises:

a metal element M,

an element M¹ selected from the group of trivalent elements other than said metal element M,

an element M² selected from the group of tetravalent elements other than said metal element M, and

nitrogen element,

said metal element M being partly replaced with a luminescent center element EC;

wherein chemical bond lengths of M¹-N and M²-N calculated from a lattice constants and atomic coordinates in the crystal structure of said fluorescent substance are within the range of ±

15% based on those of Al—

N and Si—

N, respectively, calculated from the lattice constants and atomic coordinates of Sr₂Al₃Si₇ON₁₃.

2. The substance according to claim 1, wherein the substance further comprises oxygen element.

3. The substance according to claim 1, wherein the substance has a composition represented by the formula (1):

(M<sub>1−

x</sub>EC_x)_aSi_bAlO_cN_d 

 

(1)

in which M is an element selected from the IA group elements, the IIA group elements, the IIIA group elements, the IIIB group elements, the rare earth elements and the IVA group elements;

EC is an element selected from the group consisting of Eu, Ce, Mn, Tb, Yb, Dy, Sm, Tm, Pr, Nd, Pm, Ho, Er, Cr, Sn, Cu, Zn, As, Ag, Cd, Sb, Au, Hg, TI, Pb, Bi and Fe; and

x, a, b, c and d are numbers satisfying the conditions of 0<

x<

0.4, 0.65<

a<

0.70, 2<

b<

3, 0.3<

c<

0.6 and 4<

d<

5, respectively; and

the fluorescent substance emits luminescence having a peak in the wavelength range of 570 to 650 nm when excited with light in the wavelength range of 250 to 500 nm.

4. The substance according to claim 1, produced by the process in which a nitride or carbide of said metal element M, a nitride, oxide or carbide of said element M¹, a nitride, oxide or carbide of said element M², and an oxide, nitride or carbonate of said luminescent center element EC are mixed as starting materials and then fired.

5. A light-emitting device comprising

a light-emitting chip (S1) giving off light in the wavelength range of 250 to 500 nm;

a fluorescent substance (R) comprising an inorganic compound which comprises;

a metal element M,

an element M¹ selected from the group of trivalent elements other than said metal element M,

an element M² selected from the group of tetravalent elements other than said metal element M, and

nitrogen element,

said metal element M being partly replaced with a luminescent center element EC;

wherein chemical bond lengths of M¹-N and M²-N calculated from a lattice constants and atomic coordinates in the crystal structure of said fluorescent substance are within the range of ±

15% based on those of Al—

N and Si—

N, respectively, calculated from the lattice constants and atomic coordinates of Sr₂Al₃Si₇ON₁₃; and

the substance emits luminescence having a peak in the wavelength range of 580 to 650 nm when excited with light given by said light-emitting chip (S1); and

a fluorescent substance (G) comprising an inorganic compound which comprises;

a metal element M′

,

an element M′

¹ selected from the group of trivalent elements other than said metal element M′

,

an element M′

² selected from the group of tetravalent elements other than said metal element M′

, and

nitrogen element,

said metal element M′

being partly replaced with a luminescent center element EC′

;

wherein chemical bond lengths of M′

¹-N and M′

²-N calculated from a lattice constants and atomic coordinates in the crystal structure of said fluorescent substance are within the range of ±

15% based on those of Al—

N and Si—

N, respectively, calculated from the lattice constants and atomic coordinates of Sr₃Al₃Si₁₃O₂N₂₁; and

the fluorescent substance emits luminescence having a peak in the wavelength range of 490 to 580 nm when excited with light given by said light-emitting chip (S1).

6. The device according to claim 5, wherein at least one of the fluorescent substance (R) and the fluorescent substance (G) further comprises oxygen element.

7. The device according to claim 5, wherein said fluorescent substance (R) is represented by the formula (1):

(M<sub>1−

x</sub>EC_x)_aSi_bAlO_cN_d 

 

(1)

in which M is an element selected from the IA group elements, the IIA group elements, the IIIA group elements, the IIIB group elements, the rare earth elements and the IVA group elements;

EC is an element selected from the group consisting of Eu, Ce, Mn, Tb, Yb, Dy, Sm, Tm, Pr, Nd, Pm, Ho, Er, Cr, Sn, Cu, Zn, As, Ag, Cd, Sb, Au, Hg, TI, Pb, Bi and Fe; and

x, a, b, c and d are numbers satisfying the conditions of 0<

x<

0.4, 0.65<

a<

0.70, 2<

b<

3, 0.3<

c<

0.6 and 4<

d<

5, respectively.

8. The device according to claim 5, wherein said fluorescent substance (G) is placed over said light-emitting chip and is represented by the formula (2):

(M′

<sub>1−

x</sub>EC′

_x)<sub>3−

y</sub>Al_3+zSi<sub>13−

z</sub>O_2+uN<sub>21−

w</sub> 

 

(2)

in which M′

is an element selected from the IA group elements, the IIA group elements, the IIIA group elements, the IIIB group elements, the rare earth elements and the IVA group elements;

EC′

is an element selected from the group consisting of Eu, Ce, Mn, Tb, Yb, Dy, Sm, Tm, Pr, Nd, Pm, Ho, Er, Cr, Sn, Cu, Zn, As, Ag, Cd, Sb, Au, Hg, TI, Pb, Bi and Fe; and

x, y, z, u and w are numbers satisfying the conditions of 0<

x≦

1, −

0.1≦

y≦

0.15, −

1≦

z≦

1 and −

1<

u−

w≦

1, respectively.

9. A light-emitting device comprising

a light-emitting chip (S2) giving off light in the wavelength range of 250 to 430 nm;

a fluorescent substance (R) comprising an inorganic compound which comprises;

a metal element M,

an element M¹ selected from the group of trivalent elements other than said metal element M,

an element M² selected from the group of tetravalent elements other than said metal element M, and

nitrogen element,

said metal element M being partly replaced with a luminescent center element EC;

wherein chemical bond lengths of M¹-N and M²-N calculated from a lattice constants and atomic coordinates in a crystal structure of said fluorescent substance are within the range of ±

15% based on those of Al—

N and Si—

N, respectively, calculated from the lattice constants and atomic coordinates of Sr₂Al₃Si₇ON₁₃; and

the fluorescent substance (R) emits luminescence having a peak in the wavelength range of 580 to 650 nm when excited with light given by said light-emitting chip (S2);

a fluorescent substance (G) comprising an inorganic compound which comprises;

a metal element M′

,

an element M′

¹ selected from the group of trivalent elements other than said metal element M′

,

an element M′

² selected from the group of tetravalent elements other than said metal element M′

, and

nitrogen element,

said metal element M′

being partly replaced with a luminescent center element EC′

;

wherein chemical bond lengths of M′

¹-N and M′

²-N calculated from a lattice constants and atomic coordinates in the crystal structure of said fluorescent substance are within the range of ±

15% based on those of Al—

N and Si—

N, respectively, calculated from the lattice constants and atomic coordinates of Sr₃Al₃Si₁₃O₂N₂₁; and

the fluorescent substance (G) emits luminescence having a peak in the wavelength range of 490 to 580 nm when excited with light given by said light-emitting chip (S2); and

a fluorescent substance (B) which emits luminescence having a peak in the wavelength range of 400 to 490 nm when excited with light given by said light-emitting chip (S2).

10. The device according to claim 9, wherein at least one of the fluorescent substance (R) and the fluorescent substance (G) further comprises oxygen element.

11. The device according to claim 9, wherein said fluorescent substance (R) is represented by the formula (1):

(M<sub>1−

x</sub>EC_x)_aSi_bAlO_cN_d 

 

(1)

in which M is an element selected from the IA group elements, the IIA group elements, the IIIA group elements, the IIIB group elements, the rare earth elements and the IVA group elements;

EC is an element selected from the group consisting of Eu, Ce, Mn, Tb, Yb, Dy, Sm, Tm, Pr, Nd, Pm, Ho, Er, Cr, Sn, Cu, Zn, As, Ag, Cd, Sb, Au, Hg, TI, Pb, Bi and Fe; and

x, a, b, c and d are numbers satisfying the conditions of 0<

x<

0.4, 0.65<

a<

0.70, 2<

b<

3, 0.3<

c<

0.6 and 4<

d<

5, respectively.

12. The device according to claim 9, wherein said fluorescent substance (G) is placed over said light-emitting chip and is represented by the formula (2):

(M′

<sub>1−

x</sub>EC′

_x)<sub>3−

y</sub>Al_3+zSi<sub>13−

z</sub>O_2+uN<sub>21−

w</sub> 

 

(2)

in which M′

is an element selected from the IA group elements, the IIA group elements, the IIIA group elements, the IIIB group elements, the rare earth elements and the IVA group elements;

EC′

is an element selected from the group consisting of Eu, Ce, Mn, Tb, Yb, Dy, Sm, Tm, Pr, Nd, Pm, Ho, Er, Cr, Sn, Cu, Zn, As, Ag, Cd, Sb, Au, Hg, TI, Pb, Bi and Fe; and

x, y, z, u and w are numbers satisfying the conditions of 0<

x≦

1, −

0.1≦

y≦

0.15, −

1z≦

1 and −

1<

u−

w≦

1, respectively.