Led-based white-emitting illumination unit

• US 6,504,179 B1
• Filed: 01/17/2002
• Issued: 01/07/2003
• Est. Priority Date: 05/29/2000
• Status: Expired due to Term

• Current Assignee: Osram Opto Semiconductors GmbH (Ams-Osram AG), Patent-Treuhand-Gesellschaft Fur Elektrische Gluhlampen mbH (Ams-Osram AG)
• Original Assignee: Osram Opto Semiconductors GmbH (Ams-Osram AG), Patent-Treuhand-Gesellschaft Fur Elektrische Gluhlampen mbH (Ams-Osram AG)
• Inventors: Jermann, Frank, Ostertag, Michael, Zwaschka, Franz, Ellens, Andries, Kummer, Franz
• Primary Examiner(s): Chaudhari, Chandra
• Assistant Examiner(s): VESPERMAN, WILLIAM C
• Application Number:
  US10/031,578
• Publication Number:
  US 20030006469A1
• Time in Patent Office: 355 Days
• Field of Search: 257/88, 257/98, 257/97, 257/99
• US Class Current: 257/88
• CPC Class Codes: C09K 11/77342 Silicates
• CPC Class Codes: C09K 11/7774 Aluminates
• CPC Class Codes: H01L 2224/32245 the item being metallic
• 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 2224/73265 Layer and wire connectors
• 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 33/502 Wavelength conversion materials
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

A white-emitting luminescence conversion LED uses a chlorosilicate phosphor which, in addition to Ca and Mg, contains a europium doping, and also a garnet phosphor of the rare earths, in particular Y and/or Tb. In this way, it is possible to achieve a high color rendering and a high constancy of the lighting properties under differing temperature conditions.

Claims

1. A white-emitting illumination unit, having at least one LED as light source, the LED emitting primary radiation in the 300 to 470 nm region, this radiation being partially or completely converted into longer-wave radiation by phosphors which are exposed to the primary radiation of the LED, characterized in that the conversion takes place at least with the aid of a green-emitting phosphor which originates from the class of the Eu-activated calcium magnesium chlorosilicates and of at least one yellow-emitting phosphor which originates from the class of the Ce-activated rare earth garnets.

2. The white-emitting illumination unit as claimed in claim 1, characterized in that the green-emitting phosphor satisfies the empirical formula Ca₈₋

x−

yEu_xMn_yMg(SiO₄)₄Cl₂, where x is between x=0.005 and x=1.6 and y is between y=0 and y=0.1 (in each case including cut-off values).

3. The white-emitting illumination unit as claimed in claim 1, characterized in that the yellow-emitting phosphor is a garnet of the rare earths (RE) Y, Gd, Lu, La and/or Tb, in accordance with the formula RE₃(Al,Ga)₅O₁₂:

Ce, in particular where RE=Y and/or Tb, in particular in accordance with the formula YAG;

Ce or TbAG;

Ce.

4. The white-emitting illumination unit as claimed in claim 1, characterized in that the primary emitted radiation lies in the 330 to 370 nm wavelength range, the primary emitted radiation being exposed to three phosphors with emission maxima in the blue region (430 to 470 nm), the green region (490 to 525 nm) and the yellow region (545 to 590 nm).

5. The white-emitting illumination unit as claimed in claim 1, characterized in that the primary emitted radiation lies in the blue wavelength region from 430 to 470 nm, the primary emitted blue radiation being exposed to two phosphors with emission maxima in the yellow region (545 nm to 590 nm) and in the green region (490 to 525 nm) as set forth in one of the preceding claims.

6. The white-emitting luminescence conversion LED as set forth in claim 1, characterized in that a short-wave light-emitting diode, in particular based on Ga(In)N, is used as primary radiation source.

7. The white-emitting illumination unit as claimed in claim 1, characterized in that the proportion of europium is between x=0.1 and x=1.0, without Mn additionally being used.

8. The white-emitting illumination unit as claimed in claim 1, characterized in that the illumination unit is a luminescence conversion LED in which the phosphors are in direct or indirect contact with the chip.

9. The white-emitting illumination unit as claimed in claim 1, characterized in that the illumination unit is an array of LEDs.

10. The white-emitting illumination unit as claimed in claim 9, characterized in that at least one of the phosphors is arranged on an optical device which has been arranged in front of the LED array.