Light source comprising a light-emitting element

• US 6,809,347 B2
• Filed: 12/22/2003
• Issued: 10/26/2004
• Est. Priority Date: 12/28/2000
• Status: Expired due to Term

• Current Assignee: Toyoda Gosei Company Limited (Toyota Motor Corporation)
• Original Assignee: Bitec Gbr, Leuchtstoffwerk Breitungen GmbH, Toyoda Gosei Company Limited (Toyota Motor Corporation), Tridonic Optoelectronics GmbH
• Inventors: Starick, Detlef, Roth, Gundula, Tews, Walter, Tasch, Stefan, Pachler, Peter, Kempfert, Wolfgang
• Primary Examiner(s): CRANE, SARA W
• Application Number:
  US10/250,435
• Publication Number:
  US 20040090174A1
• Time in Patent Office: 309 Days
• Field of Search: 257/103, 257/79, 257/89, 257/98
• US Class Current: 257/103
• 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. A light source to create white light, including a Light-Emitting Diode (LED) to emit a blue and/or ultraviolet emission, and at least one luminophore that absorbs a portion of the blue and/or ultraviolet emission and itself emits emission in another spectral region, comprising:

a luminophore, the luminophore including an alkaline-earth ortho-silicate activated with bivalent Europium of one of the following compounds or a mixture of these compounds;

2. The light source of claim 1, wherein at least one of the values a, b, c, and d are greater than 0.01.

3. The light source of claim 1, wherein a portion of the Silicon in the luminophore is replaced with Gallium.

4. The light source of claim 1, further comprising 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

5. The light source of claim 1, further comprising monovalent ions, particularly halogenides and/or alkali metals, in the luminophore lattice.

6. The light source of claim 1, wherein the LED emits in a spectral range of between 300 and 500 nm, the luminophore emits in a spectral range of between 430 and 650 nm, and the light source emits white light with a color reproduction index of R_a>

70.

7. The light source of claim 1, wherein one or more LED chips are arranged on a circuit board within a reflector, and the luminophore is dispersed within a light disk positioned above the reflector.

8. The light source of claim 1, wherein one or more LED chips are arranged on a circuit board within a reflector, and the luminophore is mounted on the reflector.

9. The light source of claim 7, wherein the LED chips are cast together with a transparent casting compound that possesses a domed shape.

10. The light source of claim 1, wherein the luminophore is dispersed within a casting compound that connects an arrangement of LED chips on a circuit board preferably one without gas content, whereby the polymer lens and the casting compound possess refractive indices that differ from each other by no more than 0.1.

11. The light source of claim 10, wherein the polymer lens possesses a spherical- or ellipsoid-shaped recess that is filled by the casting compound, so that the LED arrangement is secured to the polymer lens with small separation.

12. The light source of claim 1, wherein the luminophore is reduced to slurry in an inorganic matrix.

13. The light source of claim 4, further comprising a minimum of two luminophores dispersed individually within matrices that are positioned one after the other in the direction of light spread.

14. The light source of claim 1, wherein the mean grain size d₅₀ of volumetric distribution of the luminophore lies between 2 μ

m and 20 μ

m.

15. The light source of claim 8, wherein the LED chips are cast together with a transparent casting compound that possesses a domed shape.

16. The light source of claim 12, further comprising a minimum of two luminophores dispersed individually within matrices that are positioned one after the other in the direction of light spread.