FLUORESCENT SUBSTANCE AND LIGHT-EMITTING DEVICE EMPLOYING THE SAME

• US 20100025632A1
• Filed: 07/16/2009
• Published: 02/04/2010
• Est. Priority Date: 07/31/2008
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: ASAI, Hironori, FUKUDA, Yumi
• Granted Patent: US 8,685,277 B2
• Time in Patent Office: Days
• US Class Current: 252/301.60R
• CPC Class Codes: C04B 2235/3217 Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
• CPC Class Codes: C04B 2235/3852 Nitrides, e.g. oxynitrides, carbonitrides, oxycarbonitrides, lithium nitride, magnesium nitride
• CPC Class Codes: C04B 2235/3865 Aluminium nitrides
• CPC Class Codes: C04B 2235/3873 Silicon nitrides, e.g. silicon carbonitride, silicon oxynitride
• CPC Class Codes: C04B 35/597 based on silicon oxynitride, e.g. SIALONS
• CPC Class Codes: C09K 11/0883 Arsenides; Nitrides; Phosphides
• CPC Class Codes: C09K 11/7728 containing europium
• CPC Class Codes: C09K 11/77342 Silicates
• 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 2224/48247 connecting the wire to a bond pad of the item
• 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 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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 2924/181 Encapsulation
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: H01L 33/507 the elements being in intimate contact with parts other than the semiconductor body or integrated with parts other than the semiconductor body

Abstract

The present invention provides a fluorescent substance excellent both in quantum efficiency and in temperature characteristics, and also provides a light-emitting device utilizing the fluorescent substance. This fluorescent substance contains an inorganic compound comprising a metal element M, a trivalent element M¹ other than the metal element M, a tetravalent element M² other than the metal element M, and either or both of O and N. In the inorganic compound, the metal element M is partly replaced with a luminescence center element R. The crystal structure of the fluorescent substance is basically the same as Sr₃Al₃Si₁₃O₂N₂₁, but the chemical bond lengths of M¹-N and M²-N are within the range of ±15% based on those of Al—N and Si—N calculated from the lattice constants and atomic coordinates of Sr₃Al₃Si₁₃O₂N₂₁, respectively. The fluorescent substance emits luminescence having a peak in the range of 490 to 580 nm when excited with light of 250 to 500 nm.

Claims

1. A fluorescent substance containing 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 either or both of O and N, provided that said metal element M is partly replaced with a luminescence center element R;

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

15% based on those of Al—

N and Si—

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

2. The fluorescent substance according to claim 1, wherein

said metal element M is 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,

said element M¹ is selected from the IIIA group elements and the IIIB group element, and

said element M² is selected from the IVA group elements and the IVB group elements.

3. The fluorescent substance according to claim 1, wherein

said metal element M is selected from the group consisting of Li, Na, K, Mg, Ca, Sr, Ba, B, Ga, In, Y, Sc, Gd, La, Lu and Ge,

said element M¹ is selected from the group consisting of Al, B, Ga, In, Sc, Y, La, Gd and Lu, and

said element M² is selected from the group consisting of Si, Ge, Sn, Ti, Zr and Hf.

4. The fluorescent substance according to claim 1, wherein said luminescence center element R is 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, Tl, Pb, Bi and Fe.

5. The fluorescent substance according to claim 1, which emits luminescence having a peak in the wavelength range of 490 to 580 nm when excited with light in the wavelength range of 250 to 500 nm.

6. The fluorescent substance according to claim 1, characterized

by having a composition represented by the following formula (1):

(M_1-xR_x)_3-yAl_3+zSi<sub>13−

z</sub>O_2+uN_21-w  

 

(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;

R is another 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, Tl, 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; and

by emitting luminescence having a peak in the wavelength range of 490 to 580 nm when excited with light in the wavelength range of 250 to 500 nm.

7. A process for preparation of the fluorescent substance according to claim 1, characterized in that 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 luminescence center element R are mixed as starting materials and then fired.

8. The process according to claim 7 for preparation of the fluorescent substance, wherein the mixed starting materials are fired at a temperature of 1500 to 2000°

C. under a pressure of not less than 5 atmospheres.

9. A light-emitting device characterized by comprising

a light-emitting element giving off light in the wavelength range of 250 to 500 nm, and

a phosphor layer which is provided on said light-emitting element and which contains the fluorescent substance according to claim 1.