Light sources with serially connected LED segments including current blocking diodes
View Patent ↗A light source and method for making the same are disclosed. The light source includes a substrate and a light emitting structure that is deposited on the substrate. A barrier divides the light emitting structure into first and second segments that are electrically isolated from one another. A serial connection electrode connects the first segment in series with the second segment. A first blocking diode between the light emitting structure and the substrate prevents current from flowing between the light emitting structure and the substrate when the light emitting structure is emitting light. The barrier extends through the light emitting structure into the first blocking diode.
1. A light source comprising
a substrate;
a light emitting structure deposited on said substrate;
a barrier that divides said light emitting structure into first and second segments;
a serial connection electrode that connects said first segment in series with said second segment; and
a first blocking diode between said light emitting structure and said substrate, said first blocking diode preventing current from flowing between said light emitting structure and said substrate when said light emitting structure is emitting light,
wherein said barrier extends through said light emitting structure into said first blocking diode.
2. The light source of claim 1 wherein said substrate comprises a transition layer of semiconductor material that is transparent to light generated by said light emitting structure and wherein said barrier comprises a trench extending through said light emitting structure and terminating in said transition layer.
3. The light source of claim 1 further comprising a second blocking diode between said first blocking diode and said substrate, said second blocking diode preventing current from flowing between said light emitting structure and said substrate when said light emitting structure is emitting light.
4. The light source of claim 1 wherein said serial connection electrode comprises a plurality of isolated conductors that span said barrier.
5. The light source of claim 2 wherein said barrier does not substantially interrupt light traveling in said transition layer.
6. The light source of claim 2 wherein said serial connection electrode comprises a layer of electrically conducting material deposited in said trench, said trench having an insulating layer that prevents said layer of electrically conducting material from making direct contact with walls of said light emitting structure that are exposed in said trench.
7. The light source of claim 2 comprising an insulating layer underlying a portion of said serial connection electrode that overlies said light emitting structure.
8. The light source of claim 1 wherein said semiconductor materials comprise alloy compositions of GaN, InN, and AlN.