Light emitting device for AC power operation

1. A light-emitting device, comprising:

a first power source connection terminal and a second power source connection terminal, the first and second power source connection terminals configured to be connected to an external power source;

a plurality of light emitting cell arrays, each of the plurality of the light emitting cell arrays being connected in parallel to one another between the first and the second power source connection terminals, each of the plurality of light emitting cell arrays comprising serially connected light emitting cells, each of the light emitting cells comprising;

a first conductivity-type semiconductor layer;

a second conductivity-type semiconductor layer;

an active layer disposed between the first conductivity-type semiconductor layer and the second conductivity-type semiconductor layer; and

an electrode pad disposed on the second conductivity-type semiconductor layer; and

a switching block connected to the first power source terminal, the second power source connection terminal, and each of the light emitting cell arrays,

wherein a first group of the light emitting cell arrays are connected in parallel to the switching block and a second group of the light emitting cell arrays are connected in reverse parallel to the switching block,

wherein the switching block is configured to sequentially turn on and off each of the plurality of light emitting cell arrays when an alternating current (AC) voltage is applied to the light emitting device, and

wherein each of the plurality of light emitting cell arrays is disposed on a single substrate.

2. The light-emitting device of claim 1 , further comprising:

a transparent electrode disposed between the second conductivity-type semiconductor layer and the electrode pad.

3. The light-emitting device of claim 1 , wherein at least one of the light emitting cells comprises an inclined side surface.

4. The light-emitting device of claim 1 , wherein the second conductivity-type semiconductor layer of at least one light emitting cell comprises a roughened surface.

5. A light-emitting device of claim 1 , wherein each of the plurality of light emitting cell arrays comprises a wire connecting a first conductivity-type semiconductor layer of a first light emitting cell to an electrode pad on a second light emitting cell adjacent to the first light emitting cell.

6. The light-emitting device of claim 1 , wherein each of the plurality of light emitting cell arrays is configured to receive the same voltage.

7. The light-emitting device of claim 1 , wherein each of the plurality of light emitting cell arrays is configured to operate in response to alternating current (AC) power.

8. The light-emitting device of claim 1 , further comprising:

a plurality of second power source connection terminals, wherein each of the plurality of light emitting cell arrays is respectively connected to a second power source connection terminal.

9. The light-emitting device of claim 8 , wherein the switching block is connected to the first power source terminal, each of the plurality of second power source connection terminals, and each of the plurality of light emitting cell arrays.

10. The light-emitting device of claim 9 , wherein the switching block is configured to form current paths between each of the plurality of second power source connection terminals, each of the plurality of light emitting cell arrays, and the external power source.

11. A light-emitting device, comprising:

a first power source connection terminal and a second power source connection terminal, the first and second power source connection terminals configured to be connected to an external power source;

a plurality of light emitting cell arrays, each of the plurality of light emitting cell arrays being connected in parallel to one another between the first and the second power source connection terminals, each of the plurality of light emitting cell arrays comprising serially connected light emitting cells, each of the light emitting cells comprising;

a first conductivity-type semiconductor layer;

a second conductivity-type semiconductor layer;

an active layer disposed between the first conductivity-type semiconductor layer and the second conductivity-type semiconductor layer; and

an electrode pad disposed on the second conductivity-type semiconductor layer; and

a switching block connected to end portions of each of the plurality of light emitting cell arrays and configured to receive power from an alternating current (AC) power source, the switching block configured to individually and sequentially operate to each of the plurality of light emitting cell arrays, depending on a voltage level of the AC power source, such that when one light emitting cell array is turned on, another light emitting cell array is electrically bypassed by the switching block.

12. The light-emitting device of claim 11 , wherein the plurality of light emitting cell arrays comprises:

first light emitting cell arrays each comprising a different number of light emitting cells that are all connected to one another in series, the first arrays being connected in parallel to one another; and

second light emitting cell arrays each comprising a different number of light emitting cells that are all connected to one another in series, the light emitting cells of the second light emitting cell arrays being connected in reverse parallel to the light emitting cells of the first light emitting cell arrays.