Light source comprising a light-emitting element

• US 20040090174A1
• Filed: 12/22/2003
• Published: 05/13/2004
• Est. Priority Date: 12/28/2000
• Status: Active Grant

• Current Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Original Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Inventors: Starick, Detlef, Roth, Gundula, Tews, Walter, Tasch, Stefan, Pachler, Peter, Kempfert, Wolfgang
• Granted Patent: US 6,809,347 B2
• Time in Patent Office: Days
• US Class Current: 313/503
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: C09K 11/7734 Aluminates
• CPC Class Codes: C09K 11/77344 Aluminosilicates
• CPC Class Codes: C09K 11/774 Borates
• CPC Class Codes: C09K 11/7795 Phosphates
• CPC Class Codes: F21Y 2105/10 comprising a two-dimensional array of point-like light-generating elements
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/0073 Light emitting diode [LED]
• CPC Class Codes: H01L 2224/16145 the bodies being stacked
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/32257 the layer connector connecting to a bonding area disposed in a recess of the surface of the item
• CPC Class Codes: H01L 2224/45139 Silver (Ag) as principal constituent
• 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 2224/48257 connecting the wire to a die pad of the item
• CPC Class Codes: H01L 2224/49107 on the semiconductor or solid-state body
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• 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 2924/00011 : Not relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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 2924/01049 : Indium [In]
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 2933/0091 : Scattering means in or on the semiconductor body or semiconductor body package H01L33/22 takes precedence
• CPC Class Codes: H01L 33/06 : within the light emitting region, e.g. quantum confinement structure or tunnel barrier
• CPC Class Codes: H01L 33/32 : containing nitrogen
• CPC Class Codes: H01L 33/502 : 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
• CPC Class Codes: Y02B 20/00 : Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

The invention relates to a light source comprising a light-emitting element, which emits light in a first spectral region, and comprising a luminophore, which comes from the group of alkaline-earth orthosilicates and which absorbs a portion of the light emitted by the light source and emits light in another spectral region. According to the invention, the luminophore is an alkaline-earth orthosilicate, which is activated with bivalent europium and whose composition consists of: (2-x-y)SrOx(Ba, Ca)O(1-a-b-c-d)SiO₂aP₂O₅bAl₂O₃cB₂O₃dGeO₂:yEu²⁺ and/or (2-x-y)BaOx((Sr, Ca)O(1-a-b-c-d)SiO₂aP₂O₅bAl₂O₃cB₂O₃dGeO₂:yEu²⁺. The desired color (color temperature) can be easily adjusted by using a luminophore of the aforementioned type. The light source can contain an additional luminophore selected from the group of alkaline-earth aluminates, activated with bivalent europium and/or manganese, and/or can contain an additional red-emitting luminophore selected from the group Y(V, P, Si)O₄:Eu or can contain alkaline-earth magnesium disilicate.

Claims

1. Light source with a light-emitting element that emits in a first spectral region, preferably in the blue and/or ultraviolet region of the visual spectrum, and with a luminophore that is from the group of alkaline-earth ortho-silicates, or that contains at least a portion from this group of luminescent materials, and that absorbs a portion of the emission from the luminescent element and emits in another region of the spectrum, preferably in yellow-green, yellow, or orange region, characterized in that the luminophore is an alkaline-earth ortho-silicate activated with bivalent Europium of the composition:

(2-x-y)SrO.x(Ba_u, Ca_v)O.(1-a-b-c-d)SiO₂.aP₂O₅bAl₂O₃cB₂O₃dGeO₂;

yEu²⁺

where

0≦

x<

1.6 0.005<

y<

0.5 x+y≦

1.6

0≦

a,b,c,d<

0.5 u+v=1

applies;

and/or an alkaline-earth ortho-silicate of the following composition;

(2-x-y)BaO.x(Sr_u, Ca_v)O.(1-a-b-c-d)SiO₂.aP₂O₅bAl₂O₃cB₂O₃dGeO₂;

yEu²⁺

where

0.01<

x<

1.6 0.005<

y<

0.5

0≦

a,b,c,d<

0.5 u+v=1 x·

u≧

0.4

applies, whereby preferably at least one of the values a, b, c, and d is greater than 0.01.

2. Light source as in claim 1, characterized in that a portion of the Silicon in the luminophore is replaced with Gallium.

3. Light source as in one of claims 1 or 2, characterized in that it contains an additional luminophore from the group of alkaline-earth aluminates activated using bivalent Europium and/or Manganese, and/or a second, additional red-emitting luminophore of the group Y(V,P,Si)O₄:

Eu,Bi, Y₂O₂S;

Eu,Bi, or ;

Eu²⁺,Mn²⁺ alkaline-earth Magnesium di-silicates with the formula

Me_(3-x-y)MgSi₂O₈;

xEu,yMn,

whereby

0.005<

x<

0.5 0.005<

y<

0.5

and Me═

Ba and/or Sr and/or Ca applies.

4. Light source as in one of claims 1 through 3, characterized in that monovalent ions, particularly halogenides and/or alkali metals, are included in the luminophore lattice.

5. Light source as in one of claims 1 through 4, characterized in that its first spectral region lies between 300 and 500 nm.

6. Light source as in one of claims 1 through 5, characterized in that its second spectral region lies between 430 and 650 nm.

7. Light source as in one of claims 1 through 6, characterized in that it emits white light with Ra values >

70, preferably >

72.

8. Light source as in one of claims 1 through 7, characterized in that it includes at least two different luminophores, whereby at least one is an alkaline-earth ortho-silicate luminescent material.

9. Light source as in one of claims 1 through 8, characterized in that one or more LED chips (1) are arranged on a circuit board (2) within a reflector (4), and the luminophore (6) is dispersed within a light disk (5) positioned above the reflector (4) (FIG. 7).

10. Light source as in one of claims 1 through 8, characterized in that one or more LED chips (1) are arranged on a circuit board (2) within a reflector (4), and the luminophore (6) is mounted on the reflector (4) (FIG. 8).

11. Light source as in one of claims 1 or 10, characterized in that the LED chips (1) are cast together with a transparent casting compound (3,3′

) that possesses a domed shape.

12. Light source as in one of claims 1 through 11, characterized in that the luminophore is dispersed within a casting compound (3) that connects an arrangement of LED chips (1) on a circuit board (2) and a polymer lens (7), preferably one without gas content, whereby the polymer lens (7) and the casting compound (3) possess refractive indices that differ from each other by no more than 0.1 (FIG. 10).

13. Light source as in claim 12, characterized in that the polymer lens (7) possesses a spherical- or ellipsoid-shaped recess that is filled by the casting compound (3), so that the LED arrangement (1′

) is secured to the polymer lens (7) with small separation (FIG.

     10).

14. Light source as in one of claims 1 through 13, characterized in that the luminophore is reduced to slurry in a preferably inorganic matrix.

15. Light source as in claims 8 and 14, characterized in that the minimum of two luminophores are dispersed individually within matrices that are positioned one after the other in the direction of light spread.

16. Light source as in one of claims 1 through 15, characterized in that the mean grain size d₅₀ of volumetric distribution lies between 2 μ

m and 20 μ

m.