Structure of AC light-emitting diode dies
A structure of light-emitting diode (LED) dies having an AC loop (a structure of AC LED dies), which is formed with at least one unit of AC LED micro-dies disposed on a chip. The unit of AC LED micro-dies comprises two LED micro-dies arranged in mutually reverse orientations and connected with each other in parallel, to which an AC power supply may be applied so that the LED unit may continuously emit light in response to a positive-half wave voltage and a negative-half wave voltage in the AC power supply. Since each AC LED micro-die is operated forwardly, the structure of AC LED dies also provides protection from electrical static charge (ESD) and may operate under a high voltage.
1. A structure of AC light-emitting diode (LED) dies, comprising:
a substrate;
two layers of a first conductivity type that are supported on the substrate and separated from each other, each of the layers of the first conductivity type having a wide end and a narrow end;
two layers of a second conductivity type that are supported respectively on the two layers of the first conductivity type, each of the layers of the second conductivity type having a wide end and a narrow end;
a first pad formed on one of the two layers of the first conductivity type, the first pad being disposed adjacent the narrow end of said one of the two layers of the first conductivity type;
a second pad formed on one of the two layers of the second conductivity type, the second pad being disposed adjacent the wide end of said one of the two layers of a second conductivity type;
a first conductive bridge that electrically connects the first pad to the second pad;
another first pad formed on the other of the two layers of the first conductivity type, the another first pad being disposed adjacent the narrow end of said other of the two layers of the first conductivity type; and
another second pad formed on the other of the two layers of the second conductivity type, the another second pad being disposed adjacent the wide end of said other of the two layers of the second conductivity type;
a second conductive bridge that electrically connects the another first pad to the another second pad;
wherein the AC LED emits light substantially continuously, when the first and second conductive bridges receive AC power, in response to the positive half-cycle and the negative half-cycle of the AC power.
2. The structure as recited in claim 1 , further comprising an insulating layer disposed on exposed portions of the layers of the first and second conductivity types in prevention of short-circuits between the layers and the electrical connections.
3. The structure as recited in claim 2 , wherein the two layers of the second conductivity type are supported on top surfaces of the respective layers of the first conductivity type and cover portions of the top surfaces, and wherein the insulating layer is additionally disposed on portions of the top surfaces of the layers of the first conductivity type that are not covered by the two layers of the second conductivity type.
4. The structure as recited in claim 1 , further comprising a heatsink disposed on the structure.
5. The structure as recited in claim 1 , further comprising a submount on which the first and second pads are connected to mount the structure as a flip-chip.
6. The structure as recited in claim 1 , wherein the first and second conductive bridges have lengths that are substantially the same.