Light emitting device

1. A light emitting device, comprising:

a light emitting structure comprising a plurality of light emitting regions comprising a first semiconductor layer, an active layer and a second semiconductor layer;

a first electrode disposed on the first semiconductor layer in one of the light emitting regions;

a second electrode disposed on the second semiconductor layer in another of the light emitting regions;

at least one connection electrode to sequentially connect the light emitting regions in series; and

at least one intermediate pad disposed on the first or second semiconductor layer in at least still another of the light emitting regions,

wherein the light emitting regions connected in series are divided into 1st to ith light emitting region groups,

wherein areas of light emitting regions that belong to different groups are different from each other (where 1<i≦j, each of i and j is a natural number, and j is a last light emitting region group),

wherein an area of a light emitting region which is more frequently used among the plurality of light emitting regions is larger than an area of a light emitting region which is less frequently used among the plurality of light emitting regions,

wherein the first electrode is configured to be supplied with a first power, and

wherein any one of the at least one intermediate pad and the second electrode is configured to be supplied with a second power.

2. The light emitting device according to claim 1 , wherein areas of light emitting regions that belong to the same group are identical.

3. The light emitting device according to claim 1 , wherein at least one of a transverse length and a longitudinal length of light emitting regions that belong to different groups are different.

4. The light emitting device according to claim 1 ,

wherein the at least one intermediate pad is disposed on the second semiconductor layer or the first semiconductor layer in the last light emitting region among light emitting regions that belong to at least one of groups other than the jth group.

5. The light emitting device according to claim 4 , wherein the first electrode corresponds to a common negative terminal,

wherein the second electrode corresponds to one of positive terminals, and

wherein the at least one intermediate pad corresponds to others of the positive terminals.

6. The light emitting device according to claim 5 , wherein areas of light emitting regions that belong to a group closer to the common negative terminal are larger than areas of light emitting regions that belong to a group farther from the common negative terminal.

7. The light emitting device according to claim 1 , further comprising:

an insulating layer disposed in the light emitting regions,

wherein the connection electrode is disposed on the insulating layer.

8. The light emitting device according to claim 7 , further comprising a conductive layer disposed between the insulating layer and the second semiconductor layer.

9. The light emitting device according to claim 7 , wherein the connection electrode comprises:

a first portion that passes through the insulating layer and contacts the first semiconductor layer in one of adjacent light emitting regions; and

a second portion that passes through the insulating layer, the second semiconductor layer and the active layer, and contacts the second semiconductor layer in the other of the adjacent light emitting regions,

wherein the insulating layer is disposed between the second portion and the second semiconductor layer, and between the second portion and the active layer.

10. A light emitting device, comprising:

a light emitting structure comprising a plurality of light emitting regions comprising a first semiconductor layer, an active layer and a second semiconductor layer;

a plurality of metal layers disposed under the second semiconductor layers in the respective light emitting regions;

a first electrode disposed on the first semiconductor layer in one of the light emitting regions;

a second electrode configured to be electrically connected to the metal layer disposed under the second semiconductor layer in another of the light emitting regions;

an insulating layer configured to electrically insulate the metal layers from each other; and

at least one intermediate pad disposed on the first semiconductor layer in at least still another of the light emitting regions,

wherein the light emitting regions connected in series are divided into 1st to ith light emitting region groups,

wherein areas of light emitting regions that belong to different groups are different from each other (where 1<i≦j, each of i and j is a natural number, and j is a last light emitting region group),

wherein an area of a light emitting region which is more frequently used among the plurality of light emitting regions is larger than an area of a light emitting region which is less frequently used among the plurality of light emitting regions,

wherein any one of the at least one intermediate pad and the first electrode is configured to be supplied with a first power, and

wherein the second electrode is configured to be supplied with a second power.

11. The light emitting device according to claim 10 , wherein the second electrode is connected to the metal layer in the first light emitting region among light emitting regions that belong to the 1st group.

12. The light emitting device according to claim 10 , wherein areas of light emitting regions that belong to the same group are identical.

13. The light emitting device according to claim 10 , wherein an area of a light emitting region that belongs to an i−1th group is larger than an area of a light emitting region that belongs to an ith group.

14. The light emitting device according to claim 10 , wherein areas of light emitting regions that belong to respective groups decrease from the 1st group to the jth group in order.

15. The light emitting device according to claim 10 ,

wherein the at least one intermediate pad is disposed on the first semiconductor layer in the last light emitting region among light emitting regions that belong to at least one of groups other than the jth group.

16. The light emitting device according to claim 15 , wherein the first electrode corresponds to a common negative terminal,

wherein the second electrode corresponds to one of positive terminals, and

wherein the at least one intermediate pad corresponds to others of the positive terminals.

17. The light emitting device according to claim 16 , wherein areas of light emitting regions that belong to a group closer to the common negative terminal are larger than areas of light emitting regions that belong to a group farther from the common negative terminal.

18. The light emitting device according to claim 10 , wherein each metal layer comprises at least one of an ohmic layer and a reflective layer.

19. The light emitting device according to claim 10 , wherein the second electrode comprises:

a barrier layer configured to be electrically connected to the metal layer disposed in another of the light emitting regions; and

a support layer disposed under the barrier layer.

20. The light emitting device according to claim 10 , wherein the insulating layer electrically insulates metal layers other than the metal layer electrically connected to the second electrode, from the second electrode.