Serially-connected light emitting diodes, methods of forming same, and luminaires containing same
View Patent ↗A method of making a substantially monolithic lighting device comprising serially connected LEDs and lighting systems including the same. The serially connected LEDs may be comprised in a monolithic device comprising a first LED, a layer of conductive material, and a second LED positioned thereupon. The serially connected LEDs may also be electrically coupled to a plurality of resistors obviating the necessity of an AC/DC power converter when a luminaire containing the serially connected LEDs is connected to an AC power source.
1. A method of fabricating a lighting device comprising the steps of:
providing a substrate having a surface;
forming a substantially planar first LED on the surface of the substrate, the first LED having a surface;
attaching a substantially planar first layer of conductive material on the surface of the first LED, the conductive material having a surface;
forming a substantially planar second LED on the surface of the conductive material;
etching a plurality of troughs through each of the second LED, the first layer of conductive material, and the first LED; and
removing the substrate.
2. A method according to claim 1 wherein at least one of first LED, the second LED, and the layer of conductive material comprises a transparent material.
3. A method according to claim 1 wherein each of the first LED and second LED comprises a side surface, the method further comprising the step of attaching a color conversion layer to the side surface of at least one of the first LED and the second LED.
4. A method according to claim 1 wherein the plurality of troughs are configured in a grid pattern.
5. A method according to claim 1 wherein the second LED comprises a surface, further comprising the steps of:
attaching a second layer of conductive material to the surface of the second LED, the second layer of conductive material having a surface; and
forming a third LED on the surface of the second layer of conductive material.
6. A method according to claim 1 wherein at least one of the first LED and the second LED are formed by metalorganic chemical vapor deposition (MOCVD).
7. A method according to claim 1 wherein the first layer of conductive material is attached to the surface of the first LED by ink jet material deposition.
8. A method according to claim 1 wherein the first LED is configured to emit a first color and wherein the second LED is configured to emit a second color.
9. A method according to claim 1 wherein the step of removing the substrate results in the formation of a monolithic lighting device, the method further comprising the step of encapsulating the monolithic lighting device with a clear material.
10. A method according to claim 9 wherein the clear material is heat-conducting.