Light emitting device for display having LED stacks
A light emitting device for a display including a circuit board, a plurality of light emitting units arranged on the circuit board, each light emitting unit comprising a first LED stack including a first conductivity type semiconductor layer, a second conductivity type semiconductor layer, a first electrode disposed on the first conductivity type semiconductor layer, and a second electrode disposed on the second conductivity type semiconductor layer, a plurality of bump pads disposed between the plurality of light emitting units and the circuit board, and a bonding layer disposed between the second electrode and the circuit board, in which the second electrode has a side surface recessed inwardly with respect to a side surface of the light emitting unit to define a recessed portion, and the bonding layer is filled in the recessed portion.
1. A light emitting device for a display, comprising:
a circuit board;
a plurality of light emitting units arranged on the circuit board, each light emitting unit comprising a first LED stack including:
a first conductivity type semiconductor layer;
a second conductivity type semiconductor layer;
a first electrode disposed on the first conductivity type semiconductor layer; and
a second electrode disposed on the second conductivity type semiconductor layer, the second electrode being transparent;
a plurality of bump pads disposed between the plurality of light emitting units and the circuit board; and
a bonding layer disposed between the second electrode and the circuit board,
wherein the second electrode has a side surface recessed inwardly with respect to a side surface of the light emitting unit to define a recessed portion, and the bonding layer is filled in the recessed portion.
2. The light emitting device for a display of claim 1 , wherein each light emitting unit further comprises a second LED stack and a third LED stack, and the first, second, and third LED stacks are configured to emit one of red light, green light, and blue light, respectively.
3. The light emitting device for a display of claim 2 , wherein:
the first, second, and third LED stacks are configured to be independently driven;
light generated from the first LED stack is configured to be emitted to the outside by passing through the second LED stack and the third LED stack; and
light generated from the second LED stack is configured to be emitted to the outside by passing through the third LED stack.
4. The light emitting device for a display of claim 1 , wherein the bonding layer surrounds the second electrode and has a thickness greater than that of the second electrode.
5. The light emitting device for a display of claim 4 , wherein at least a portion of the bonding layer is disposed further away from the circuit board than the second electrode.
6. The light emitting device for a display of claim 5 , wherein at least a portion of the bonding layer is disposed further away from the circuit board than the second conductivity type semiconductor layer.
7. The light emitting device for a display of claim 1 , wherein a first angle formed by the side surface of the second electrode and a top surface of the circuit board is different from a second angle formed by a side surface of the first conductivity type semiconductor layer and the top surface of the circuit board.
8. The light emitting device for a display of claim 7 , wherein the first angle is greater than the second angle.
9. The light emitting device for a display of claim 1 , further comprising an insulation layer covering side surfaces of the light emitting unit,
wherein the bonding layer contacts the insulation layer.
10. The light emitting device for a display of claim 1 , wherein the bonding layer is transparent.
11. A light emitting device for a display, comprising:
a circuit board;
a plurality of light emitting units arranged on the circuit board, each light emitting unit comprising a first LED stack including:
a first conductivity type semiconductor layer;
a second conductivity type semiconductor layer;
an active layer disposed between the first and second conductivity type semiconductor layers and configured to generate light;
a first electrode disposed on the first conductivity type semiconductor layer; and
a second electrode disposed on the second conductivity type semiconductor layer;
a plurality of bump pads disposed between the plurality of light emitting units and the circuit board; and
a bonding layer disposed between the second electrode and the circuit board,
wherein the bonding layer is configured to transmit light generated from the active layer to the outside of the light emitting unit, and
wherein at least a portion of the bonding layer is disposed further away from the circuit board than the second electrode.
12. The light emitting device for a display of claim 11 , wherein each light emitting unit further comprises a second LED stack and a third LED stack, and the first, second, and third LED stacks are configured to emit one of red light, green light, and blue light, respectively.
13. The light emitting device for a display of claim 11 , wherein the bonding layer surrounds the second electrode and has a thickness greater than that of the second electrode.
14. The light emitting device for a display of claim 11 , wherein a first angle formed by a side surface of the second electrode and a top surface of the circuit board is greater than a second angle formed by a side surface of the first conductivity type semiconductor layer and the top surface of the circuit board.
15. A light emitting device for a display, comprising:
a circuit board;
a plurality of light emitting units arranged on the circuit board, each light emitting unit comprising a first LED stack including:
a first conductivity type semiconductor layer;
a second conductivity type semiconductor layer;
a first electrode disposed on the first conductivity type semiconductor layer; and
a second electrode disposed on the second conductivity type semiconductor layer;
a plurality of bump pads disposed between the plurality of light emitting units and the circuit board; and
a bonding layer disposed between the second electrode and the circuit board,
wherein an interval between the light emitting units is greater than a width of the light emitting unit.
16. The light emitting device for a display of claim 15 , wherein each light emitting unit further comprises a second LED stack and a third LED stack, and the first, second, and third LED stacks are configured to emit one of red light, green light, and blue light, respectively.
17. The light emitting device for a display of claim 15 , wherein the bonding layer surrounds the second electrode and has a thickness greater than that of the second electrode.
18. The light emitting device for a display of claim 17 , wherein at least a portion of the bonding layer is disposed further away from the circuit board than the second electrode.
19. The light emitting device for a display of claim 15 , wherein a first angle formed by a side surface of the second electrode and a top surface of the circuit board is greater than a second angle formed by a side surface of the first conductivity type semiconductor layer and the top surface of the circuit board.