LIGHT EMITTING DEVICE

• US 20100193807A1
• Filed: 08/11/2008
• Published: 08/05/2010
• Est. Priority Date: 08/28/2007
• Status: Active Grant

• Current Assignee: Suzhou Lekin Semiconductor Company Limited
• Original Assignee: LG Innotek Company Limited (LG Corporation)
• Inventors: Park, Jun Seok
• Granted Patent: US 8,759,846 B2
• Time in Patent Office: Days
• US Class Current: 257/88
• CPC Class Codes: H01L 2224/45015 being circular
• CPC Class Codes: H01L 2224/45139 Silver (Ag) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00011 Not relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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 2924/01049 Indium [In]
• CPC Class Codes: H01L 2924/207 Diameter ranges
• CPC Class Codes: H01L 33/641 characterized by the materials
• CPC Class Codes: H01L 33/642 characterized by the shape
• CPC Class Codes: H05K 1/0206 by printed thermal vias
• CPC Class Codes: H05K 1/0209 External configuration of printed circuit board adapted for heat dissipation, e.g. lay-out of conductors, coatings
• CPC Class Codes: H05K 2201/0209 Inorganic, non-metallic particles
• CPC Class Codes: H05K 2201/09318 Core having one signal plane and one power plane
• CPC Class Codes: H05K 2201/09663 Divided layout, i.e. conductors divided in two or more parts branched layout H05K2201/09254
• CPC Class Codes: H05K 2201/09781 Dummy conductors, i.e. not used for normal transport of current; Dummy electrodes of components
• CPC Class Codes: H05K 2201/10106 Light emitting diode [LED]

Abstract

A light emitting device is provided. The light emitting device comprises a substrate, a first lead frame and a second lead frame on the substrate, a first light emitting diode, a heat conductor on the substrate, and a heat transfer pad. The first light emitting diode on the first lead frame is electrically connected to the first lead frame and the second lead frame. The heat conductor is electrically separated from the first lead frame. The heat transfer pad contacts the first lead frame and the heat conductor thermally to connect the first lead frame to the heat conductor.

Claims

1. A light emitting device comprising:

a substrate;

a first lead frame and a second lead frame on the substrate;

a first light emitting diode on the first lead frame electrically connected to the first lead frame and the second lead frame;

a heat conductor on the substrate, the heat conductor being electrically separated from the first lead frame; and

a heat transfer pad contacting the first lead frame and the heat conductor to thermally connect the first lead frame to the heat conductor.

2. The light emitting device according to claim 1, wherein the first lead frame and the first light emitting diode are in contact with each other or are electrically connected to each other through a wire.

3. The light emitting device according to claim 1, wherein the second lead frame is electrically connected to the first light emitting diode through a wire.

4. The light emitting device according to claim 1, wherein the heat conductor is connected to a via hole penetrating the substrate.

5. The light emitting device according to claim 4, wherein the via hole is connected to a metal layer under the substrate.

6. The light emitting device according to claim 1, wherein the heat transfer pad is at least one of tape, paint, and resin.

7. The light emitting device according to claim 1, wherein one of the first lead frame and the heat conductor comprises a protruding portion and the other of the first lead frame and the heat conductor comprises a recessed portion surrounding the protruding portion.

8. The light emitting device according to claim 1, wherein a part of a portion of the first lead frame that contacts the heat transfer pad is formed of a material with heat conductivity higher than that of a portion of the first lead frame that does not contact the heat transfer pad.

9. The light emitting device according to claim 1, wherein a part of a portion of the heat conductor that contacts the heat transfer pad is formed of a material with heat conductivity higher than that of a portion of the heat conductor that does not contact the heat transfer pad.

10. The light emitting device according to claim 1, wherein the heat transfer pad thermally connects the second lead frame to the heat conductor.

11. The light emitting device according to claim 1, wherein the heat transfer pad is disposed on the first lead frame, the heat conductor, and an exposed portion of the substrate between the first lead frame and the heat conductor.

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

a third lead frame and a fourth lead frame on the substrate; and

a second light emitting diode on the third lead frame electrically connected to the third lead frame and the fourth lead frame,

wherein the second lead frame and the third lead frame are integrally formed with each other or are electrically connected to each other through a wire.

13. A light emitting device comprising:

a substrate;

a first lead frame and a second lead frame on the substrate;

a heat conductor on the substrate, the heat conductor being electrically separated from the first lead frame and the second lead frame; and

a light emitting diode on the heat conductor being electrically connected to the first lead frame and the second lead frame.

14. The light emitting device according to claim 13, wherein the heat conductor is connected to a via hole penetrating the substrate, and the via holes is connected to a metal layer under the substrate.

15. A light emitting device comprising:

a substrate;

a first lead frame, a second lead frame, a third lead frame, and a fourth lead frame on the substrate;

a first heat conductor and a second heat conductor on the substrate;

a first light emitting diode on the first heat conductor being electrically connected to the first lead frame and the second lead frame;

a second light emitting diode on the third lead frame being electrically connected to the third lead frame and the fourth lead frame; and

a heat transfer pad contacting the third lead frame and the second heat conductor to thermally connect the third lead frame to the second heat conductor.

16. The light emitting device according to claim 15, wherein the first heat conductor and the second heat conductor are connected to a via hole penetrating the substrate, and the via holes is connected to a metal layer under the substrate.

17. The light emitting device according to claim 15, wherein the heat transfer pad is disposed on the third lead frame, the second heat conductor, and an exposed portion of the substrate between the third lead frame and the second heat conductor.

18. The light emitting device according to claim 15, wherein the heat transfer pad is at least one of tape, paint, and resin.

19. The light emitting device according to claim 15, comprising:

a fifth lead frame and a six lead frame on the substrate; and

a third light emitting diode on the fifth lead frame electrically connected to the fifth lead frame and the sixth lead frame,

wherein the fourth lead frame and the fifth lead frame are integrally formed with each other or are electrically connected to each other through a wire.

20. The light emitting device according to claim 15, comprising:

a seventh lead frame, a eighth lead frame, and a third heat conductor on the substrate; and

a fourth light emitting diode on the third heat conductor,

wherein the fourth light emitting diode is electrically connected to the seventh lead frame and the eighth lead frame.