Thin film phosphor-converted light emitting diode device

• US 20040164307A1
• Filed: 02/23/2004
• Published: 08/26/2004
• Est. Priority Date: 09/27/1999
• Status: Active Grant

• Current Assignee: Lumileds LLC (Apollo Global Management, Inc.)
• Original Assignee: Lumileds Lighting US LLC (Apollo Global Management, Inc.)
• Inventors: Mueller-Mach, Regina B., Mueller, Gerd O.
• Granted Patent: US 7,183,577 B2
• Time in Patent Office: Days
• US Class Current: 257/89
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector
• CPC Class Codes: H01L 33/50 Wavelength conversion elements
• CPC Class Codes: H01L 33/504 Elements with two or more wavelength conversion materials
• CPC Class Codes: Y10S 257/918 Light emitting regenerative switching device, e.g. light emitting scr arrays, circuitry

Abstract

A light emitting diode capable of emitting first light having a first peak wavelength is combined with a first phosphor layer overlying the light emitting diode, the first phosphor layer capable of absorbing the first light and emitting second light having a second peak wavelength and a second phosphor layer overlying the light emitting diode, the second phosphor layer capable of emitting third light having a third peak wavelength.

Claims

1. A device comprising:

a light emitting diode capable of emitting first light having a first peak wavelength;

a first phosphor layer overlying the light emitting diode, the first phosphor layer capable of absorbing the first light and emitting second light having a second peak wavelength; and

a second phosphor layer overlying the light emitting diode, the second phosphor layer capable of emitting third light having a third peak wavelength.

2. The device of claim 1 wherein the first phosphor layer and the second phosphor layer are thin films comprising dopants spatially distributed in an optically homogenous manner.

3. The device of claim 1 wherein the first phosphor layer and the second phosphor layer are separate layers.

4. The device of claim 1 wherein:

the second peak wavelength is longer than the first peak wavelength; and

the third peak wavelength is longer than the second peak wavelength.

5. The device of claim 4 wherein:

the first peak wavelength is blue;

the second peak wavelength is green; and

the third peak wavelength is red.

6. The device of claim 4 further comprising a third phosphor layer overlying the light emitting diode, capable of emitting fourth light having a fourth peak wavelength.

7. The device of claim 6 wherein:

the first peak wavelength is UV;

the second peak wavelength is blue;

the third peak wavelength is green; and

the fourth peak wavelength is red.

8. The device of claim 6 wherein the first, second, and third phosphor layers form a checkerboard pattern.

9. The device of claim 4 wherein the second phosphor layer is adjacent to the light emitting diode and the first phosphor layer overlies the second phosphor layer.

10. The device of claim 4 wherein each of the first and second phosphor layers is adjacent to the light emitting diode and the first and second phosphor layer form a checkerboard pattern.

11. The device of claim 1 wherein the light emitting diode comprises:

a substrate having a first surface and a second surface opposite the first surface; and

a stack of semiconductor layers adjacent the first surface;

wherein the first and second phosphor layers are disposed on the second surface.

12. The device of claim 1 wherein the first and second phosphor layers are formed such that a portion of the first light is unconverted by the first and second phosphor layers.

13. The device of claim 12 wherein a combination of the first, second, and third light appears white.

14. The device of claim 1 further comprising a dielectric mirror disposed between the light emitting diode and the first phosphor layer.

15. The device of claim 14 wherein the dielectric mirror transmits the first light and reflects the second and third light.