Compact multi-LED light source with improved heat dissipation
A light source having a substrate having first and second surfaces is disclosed. The substrate has first and second conducting traces on the first surface. A heat conducting metallic layer is attached to the second surface. First and second LEDs are disposed on the first surface, each LED having first and second contacts for powering that LED. The first contact is connected to a corresponding one of the first and second conducting traces. First and second conducting vias are in contact with the first and second LEDs, respectively. The first and second conducting vias extend from the first surface through the substrate and contact the heat conducting metallic layer. The second contacts of the first and second LEDs are electrically connected to the first and second conducting vias, respectively. The LEDs are powered by applying potentials between the external terminals and the heat-conducting layer.
1 . A light source comprising:
a substrate having first and second surfaces, said substrate having first and second conducting traces on said first surface;
a heat conducting metallic layer attached to said second surface;
first and second LEDs disposed on said first surface, each LED having first and second contacts for powering that LED, said first contact being connected to a corresponding one of said first and second conducting traces;
first and second conducting vias in contact with said first and second LEDs, respectively, said first and second conducting vias extending from said first surface through said substrate and contacting said heat conducting metallic layer, said second contacts of said first and second LEDs being electrically connected to said first and second conducting vias, respectively; and
first and second external terminals disposed on said second surface, said first and second external terminals being connected to said first and second conducting traces.
2 . The light source of claim 1 further comprising a thermal mass in contact with said first surface and thermally connected to said heat conducting metallic layer.
3 . The light source of claim 2 wherein said thermal mass further comprises a reflecting cup that extends above said LEDs and reflects light leaving said LEDs.
4 . The light source of claim 1 wherein said first LED is powered by applying electrical potential between said first external terminal and said heat conducting metallic layer, and said second LED is powered by applying a potential between said second external terminal and said heat conducting metallic layer.