Light-emitting device, light-emitting device package and lighting system

• US 8,357,949 B2
• Filed: 03/24/2011
• Issued: 01/22/2013
• Est. Priority Date: 03/25/2010
• Status: Active Grant

• Current Assignee: Suzhou Lekin Semiconductor Company Limited
• Original Assignee: LG Innotek Company Limited (LG Corporation)
• Inventors: Lim, Woosik, Choo, Sungho, Beom, Heeyoung, Kim, Sungkyoon
• Primary Examiner(s): Coleman, William D
• Assistant Examiner(s): ENAD, CHRISTINE A
• Application Number:
  US13/071,195
• Publication Number:
  US 20110233589A1
• Time in Patent Office: 670 Days
• Field of Search: 257/98, 257/E33.068, 257/E33.067, 313/421, 313/423, 438/29
• US Class Current: 257/98
• CPC Class Codes: H01L 2224/16 of an individual bump connector
• CPC Class Codes: H01L 2224/16245 the item being metallic
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 33/405 Reflective materials
• CPC Class Codes: H01L 33/486 adapted for surface mounting

Abstract

A light-emitting device includes a substrate, a light-emitting structure on the substrate, the light-emitting structure including a first semiconductor layer, an active layer and a second semiconductor layer, a light-transmitting electrode layer on the second semiconductor layer, and a first reflective layer on the light-transmitting electrode layer, wherein the first reflective layer includes a first layer having a first index of refraction and a second layer having a second index of refraction different from the first index of refraction. Based on this configuration, it is possible to protect the light-emitting device and improve luminous efficiency thereof.

Claims

1. A light-emitting device comprising:

a substrate;

a light-emitting structure on the substrate, the light-emitting structure including a first semiconductor layer, an active layer and a second semiconductor layer;

a light-transmitting electrode layer on the second semiconductor layer;

a second electrode pad on the light-transmitting electrode layer;

a first reflective layer on the light-transmitting electrode layer; and

a second reflective layer arranged in the light-transmitting electrode layer,

wherein the first reflective layer comprises a first layer having a first index of refraction and a second layer having a second index of refraction different from the first index of refraction, and

wherein the second reflective layer at least partially vertically overlaps the second electrode pad and includes a third layer having a third index of refraction and a fourth layer having a fourth index of refraction different from the third index of refraction.

2. The device according to claim 1, wherein the first layer has a lower index of refraction than the second layer.

3. The device according to claim 1, wherein the first layer has an index of refraction of 1.4 to 1.6.

4. The device according to claim 1, wherein at least one of the first layer and the second layer comprises at least one of SiO₂, Al₂0₃ and TiO₂.

5. The device according to claim 1, wherein the first layer and the second layer are repeatedly alternately laminated.

6. The device according to claim 1, wherein the first layer and the second layer have a thickness of 2 Å

to 10 um.

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

a first electrode pad on the partially exposed top of the first semiconductor layer,

wherein the first reflective layer is on the top of the light-transmitting electrode layer and the exposed top of the first semiconductor layer.

8. The device according to claim 7, wherein the first reflective layer extends from the top of the light-transmitting electrode layer to the top of the first semiconductor layer along the side of the active layer and the second semiconductor layer.

9. The device according to claim 7, further comprising:

an opening provided in a region of the light-transmitting electrode layer,

wherein the second electrode pad is on the opening and the second reflective layer contacts the second electrode pad and the second semiconductor layer.

10. The device according to claim 7, wherein the third layer has a lower index of refraction than that of the fourth layer.

11. The device according to claim 7, wherein the third layer has an index of refraction of 1.4 to 1.6.

12. The device according to claim 7, wherein at least one of the third layer and the fourth layer includes at least one of SiO₂, Al₂0₃ and TiO₂.

13. The device according to claim 7, wherein the third layer and the fourth layer are repeatedly alternately laminated.

14. The device according to claim 7, wherein the third layer and the fourth layer have a thickness of 2 Å

to 10 um.

15. The device according to claim 7, wherein the width of the second reflective layer is greater than that of the second electrode pad.

16. The device according to claim 1, further comprising:

a buffer layer on the substrate.

17. The device according to claim 1, further comprising:

a shock buffer layer on the outer surface of the first reflective layer.

18. An emitting device package comprising:

a body;

a first lead frame and a second lead frame on the package body; and

a light-emitting device mounted on the body and electrically connected to the first and second lead frames,

wherein the light-emitting device comprises;

a substrate;

a light-emitting structure on the substrate, the light-emitting structure including a first semiconductor layer, an active layer and a second semiconductor layer;

a light-transmitting electrode layer on the second semiconductor layer;

a second electrode pad on the light-transmitting electrode layer;

a first reflective layer on the light-transmitting electrode layer; and

a second reflective layer arranged in the light-transmitting electrode layer,

wherein the first reflective layer comprises a first layer having a first index of refraction and a second layer having a second index of refraction different from the first index of refraction, and

wherein the second reflective layer at least partially vertically overlaps the second electrode pad and includes a third layer having a third index of refraction and a fourth layer having a fourth index of refraction different from the third index of refraction.

19. A lighting system, comprising:

a body; and

a light-emitting module on the body, and on which a light-emitting device is mounted,

wherein the light-emitting device comprises;

a substrate;

a light-emitting structure on the substrate, the light-emitting structure including a first semiconductor layer, an active layer and a second semiconductor layer;

a light-transmitting electrode layer on the second semiconductor layer;

a second electrode pad on the light-transmitting electrode layer;

a first reflective layer on the light-transmitting electrode layer; and

a second reflective layer arranged in the light-transmitting electrode layer,

wherein the first reflective layer comprises a first layer having a first index of refraction and a second layer having a second index of refraction different from the first index of refraction, and

wherein the second reflective layer at least partially vertically overlaps the second electrode pad and includes a third layer having a third index of refraction and a fourth layer having a fourth index of refraction different from the third index of refraction.