LED ILLUMINATION ASSEMBLY WITH COMPLIANT FOIL CONSTRUCTION

Abstract

An illumination assembly includes a compliant substrate comprising a first and second electrically conductive foil separated by an electrically insulating layer. The insulating layer includes a polymer material loaded with particles that enhance thermal conductivity of the insulating layer. A plurality of LED dies are disposed on the first conductive foil.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective illustration of a portion of an illumination assembly;

FIG. 2 is a top plan view of a portion of the illumination assembly of FIG. 1, showing a larger surface area of the illumination assembly;

FIG. 3 is an enlarged cross-sectional illustration taken along line 3-3 of FIG. 2;

FIG. 4 is an enlarged cross-sectional illustration showing another illumination assembly;

FIG. 5A is a perspective illustration of an illumination assembly having a plurality of inwardly projecting deformations having LEDs disposed therein;

FIG. 5B is a perspective illustration of an illumination assembly having an outwardly projecting deformation having LEDs disposed thereon;

FIG. 6A is a cross-sectional illustration of an illumination assembly with a compliant substrate having an inwardly projecting deformation with an LED disposed therein, wherein the substrate is conformably attached to a substrate;

FIG. 6B is another cross-sectional illustration of an illumination assembly with a compliant substrate having an inwardly projecting deformation with an LED disposed therein, wherein a thermal interface material conforms to the deformed substrate;

FIG. 6C is a cross-sectional illustration of an illumination assembly with a compliant substrate similar to FIG. 6A, showing optional use with an encapsulant and optical film;

FIG. 7 is a cross-sectional illustration of an illumination assembly with a compliant substrate having an outwardly projecting deformation with LEDs disposed thereon, wherein a thermal interface material conforms to the deformed substrate; and

FIG. 8 is a schematic illustration of one method of making an illumination assembly.

Claims

1. An illumination assembly, comprising: a compliant substrate comprising a first and second electrically conductive foil separated by an electrically insulating layer, the insulating layer comprising a polymer material loaded with particles that enhance thermal conductivity of the insulating layer; anda plurality of LED dies disposed on the first conductive foil.

2. The assembly of claim 1, wherein the compliant substrate has at least one deformation, and at least one of the LED dies is disposed on or in the deformation.

3. The assembly of claim 2, wherein the deformation is selected from a protrusion, a depression, and combinations thereof.

4. The assembly of claim 2, wherein the at least one LED die is disposed on an inclined surface of the deformation such that the LED die emits light obliquely with respect to the compliant substrate.

5. The assembly of claim 1, wherein the first electrically conductive foil is patterned to form one or more traces.

6. The assembly of claim 1, wherein the particles enhance the reflectivity of the insulating layer.

7. The assembly of claim 1, wherein the insulating layer is substantially transparent.

8. The assembly of claim 1, wherein the electrically conductive foils are composed of a metal or conductive plastic.

9. The assembly of claim 1, wherein the compliant substrate further includes a coating on the first electrically conductive foil that connects the LED dies to the first electrically conductive foil.

10. The assembly of claim 1, wherein the first and second electrically conductive foils are each thicker than the insulating layer.

11. The assembly of claim 1 in combination with: a heat sink; anda layer of thermal interface material disposed between the heat sink and the second conductive foil.

12. A backlight for a display, comprising the assembly of claim 1.

13. A method of making an illumination assembly, the method comprising: supplying a compliant substrate comprising a first and second electrically conductive foil separated by an electrically insulating layer;patterning the first electrically conductive foil;attaching a plurality of LED dies to the patterned first electrically conductive layer; andpermanently deforming the substrate to define a plurality of surface features, wherein locations of the surface features correspond to locations of the LED dies.

14. The method of claim 13, wherein the surface features have compound curvature.

15. The method of claim 13, wherein the surface features have lateral dimensions on the same order of magnitude as lateral dimensions of the LED dies.

16. The method of claim 13, wherein the permanently deforming step comprises conformably attaching the substrate to a support surface including features having compound curvature.

17. The method of claim 13, wherein the permanently deforming step comprises one of embossing, stamping, and vacuum forming the substrate.

18. The method of claim 13, wherein the permanently deforming step is performed before the attaching step.

19. The method of claim 13, wherein the supplying step comprises unwinding a roll of the compliant substrate.

20. The method of claim 19, further comprising cutting the compliant substrate at intervals to provide a plurality of illumination assembly strips, panels, or other shapes suitable for mounting in a backlight.