LED module with improved light output

• US 9,252,342 B2
• Filed: 02/26/2010
• Issued: 02/02/2016
• Est. Priority Date: 03/09/2009
• Status: Active Grant

• Current Assignee: Tridonic Jennersdorf GMBH (Zumtobel Group AG)
• Original Assignee: Tridonic Jennersdorf GMBH (Zumtobel Group AG)
• Inventors: Pachler, Peter
• Primary Examiner(s): Parker, Kenneth
• Assistant Examiner(s): Fan, Bo
• Application Number:
  US13/255,856
• Publication Number:
  US 20120061709A1
• Time in Patent Office: 2,167 Days
• Field of Search: 257/98, 257/E25.02, 257/E33.055, 257/E33.056, 257/89, 257/88, 257/99, 362/231, 362/235, 313/512, 313/498, 313/503, 313/110, 313/506, 438/22, 315/250
• US Class Current: 1/1
• CPC Class Codes: F21K 9/23 Retrofit light sources for lighting devices with a single fitting for each light source, e.g. for substitution of incandescent lamps with bayonet or threaded fittings
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• 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 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 33/54 having a particular shape
• CPC Class Codes: H01L 33/60 Reflective elements

Abstract

An LED module includes a printed circuit board (PCB) or a surface mounted device (SMD) carrier, an LED chip mounted directly or indirectly on the PCB or SMD carrier, an optical element arranged on top of the LED chip, and a white reflective layer covering a surface of the PCB or SMD carrier on which the optical element is arranged and/or partially covering the optical element.

Claims

1. An LED module comprising:

a printed circuit board (PCB) or a surface mounted device (SMD) carrier;

an LED die mounted directly or indirectly to a top surface of the PCB or SMD carrier;

an optical element arranged on top of the LED die; and

a white reflective layer covering an area of the top surface of the PCB or SMD carrier which surrounds the LED die on which said optical element is arranged, the white reflective layer contacting sidewalls of the LED die;

wherein the white reflective layer has a thickness that is less than a thickness of the LED die when viewing the LED module from a side, such that the white reflective layer does not extend above a top surface of the LED die when viewing the LED module from the side, and

wherein the thickness of the white reflective layer is between 20 μ

m and 200 μ

m measured from the top surface of the PCB or the SMD carrier.

2. The LED module according to claim 1, wherein the thickness of the white reflective layer is between 100 μ

m and 150 μ

m.

3. The LED module according to claim 1, wherein the thickness of the white reflective layer is between 75% and 90% of the thickness of the LED die.

4. The LED module according to claim 1, wherein one or more lateral side walls of the LED die are coated with a material which is arranged to be reflective of light emitted onto the LED die.

5. The LED module according to claim 1, wherein a color conversion material is present in said optical element and/or on a top surface of the LED die.

6. The LED module according to claim 5, wherein the LED module emits a white light being a mixture of a spectrum of the LED die and an emission spectrum of color conversion material.

7. The LED module according to claim 1, wherein the white reflective layer is reflective at least for a spectrum emitted by the LED die and a color conversion material.

8. The LED module according to claim 7, wherein the LED module emits a white light being a mixture of the spectrum of the LED die and an emission spectrum of the color conversion material.

9. The LED module according to claim 1, wherein the white reflective layer is an electrically non-conducting material.

10. The LED module according to claim 1, wherein a plurality of LED dies are arranged under the optical element.

11. The LED module according to claim 10, wherein at least one LED die of the plurality of LED dies emits a spectrum which is partially down-converted by a phosphor, and at least one further LED die of the plurality of LED dies emits a spectrum which is unaffected by the phosphor.

12. The LED module according to claim 1, wherein the optical element comprises a globe top.

13. The LED module according to claim 1, wherein a white reflective material is applied on a housing surrounding the LED die and/or the optical element.

14. A retrofit LED lamp, comprising at least one LED module according to claim 1.

15. The LED module according to claim 1, wherein the white reflective layer provides an improvement in light output of at least 15% throughout a visible range.

16. An LED module comprising:

a printed circuit board (PCB) or a surface mounted device (SMD) carrier;

an LED die mounted directly or indirectly to a top surface of the PCB or SMD carrier;

an optical element arranged on top of the LED die;

a white reflective layer covering an area of the top surface of the PCB or SMD carrier which surrounds the LED die;

the white reflective layer contacting sidewalls of the LED die;

a white reflective material partially covering the optical element,

wherein the white reflective layer has a thickness that is less than a thickness of the LED die when viewing the LED module from a side, such that the white reflective layer does not extend above a top surface of the LED die when viewing the LED module from the side.

17. An LED module comprising:

a printed circuit board (PCB) or a surface mounted device (SMD) carrier;

a support mounted to a top surface of the PCB or the SMD carrier;

an LED die attached to the support;

an optical element arranged on top of the LED die; and

a white reflective layer covering an area of the top surface of the PCB or SMD carrier which surrounds the LED die, the white reflective layer contacting sidewalls of the LED die,

wherein one or more dimensions of the support are equal to or smaller than one or more dimensions of the LED die when viewed from above,

wherein one or more sidewalls of the LED die emit light, and

wherein the white reflective layer has a thickness that is less than a thickness of the LED die when viewing the LED module from a side, such that the white reflective layer does not extend above a top surface of the LED die when viewing the LED module from the side.

18. The LED module according to claim 17, wherein the optical element comprises a color conversion material and/or a wavelength conversion material.

19. The LED module according to claim 17, wherein a color conversion material is on a top surface of the LED die.

20. The LED module according to claim 17, wherein the thickness of the white reflective layer is less than 50% of the thickness of the LED die.

22. The LED module according to claim 17, wherein the optical element comprises a color conversion material and/or a wavelength conversion material.

23. The LED module according to claim 17, wherein a color conversion material is on a top surface of the LED die.

21. An LED module comprising:

a printed circuit board (PCB) or a surface mounted device (SMD) carrier;

a support mounted to a top surface of the PCB or the SMD carrier;

an LED die attached to the support;

an optical element arranged on top of the LED die;

and a white reflective layer covering an area of the top surface of the PCB or SMD carrier which surrounds the LED die, the white reflective layer contacting sidewalls of the LED die,

wherein one or more dimensions of the support are equal to or smaller than one or more dimensions of the LED die when viewed from above,

wherein an area of the support surrounding the LED die is recessed, wherein one or more sidewalls of the LED die emit light, and

wherein the white reflective layer has a thickness that is less than 50% of a thickness of the LED die when viewing the LED module from a side such that the white reflective layer does not extend above a top surface of the LED die when viewing the LED module from the side.