Lead frame having light-reflecting layer, light emitting diode having the lead frame, and backlight unit having the light emitting diode

• US 8,288,785 B2
• Filed: 01/09/2009
• Issued: 10/16/2012
• Est. Priority Date: 12/03/2008
• Status: Expired due to Fees

• Current Assignee: Seoul Semiconductor Co., Ltd.
• Original Assignee: Seoul Semiconductor Co., Ltd.
• Inventors: Cho, Jae-Ho, Yoon, Sean-Jhin, Kim, Tae-Kwang, Kim, Kyung-Nam
• Primary Examiner(s): Pizarro, Marcos D.
• Assistant Examiner(s): Jahan, Bilkis
• Application Number:
  US12/351,480
• Publication Number:
  US 20100133565A1
• Time in Patent Office: 1,376 Days
• Field of Search: 257 99-100, 257/666
• US Class Current: 257/98
• 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 2924/00012 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 2924/181 Encapsulation
• CPC Class Codes: H01L 33/46 Reflective coating, e.g. dielectric Bragg reflector
• CPC Class Codes: H01L 33/60 Reflective elements
• CPC Class Codes: H01L 33/62 Arrangements for conducting electric current to or from the semiconductor body, e.g. lead-frames, wire-bonds or solder balls

Abstract

An LED includes a light-emitting chip, a metal member, and a housing. The light-emitting chip generates light. The light-emitting chip is arranged on the metal member. The housing is combined with the metal member to fix the metal member. The housing has an opening portion exposing at least a portion of the light-emitting chip and the metal member. The metal member includes a base metal layer, a light-reflecting layer arranged on the base metal layer, and a protection layer arranged on the light-reflecting layer and including a metal.

Claims

1. A light emitting diode (LED), comprising:

a metal member comprising a base metal layer, a light-reflecting layer disposed on the base metal layer, and a protection layer disposed on the light-reflecting layer and comprising a metal;

a light-emitting chip attached directly to the metal member; and

a housing to fix the metal member, the housing having an opening portion exposing the light-emitting chip and a portion of the metal member,

wherein the exposed portion of the metal member comprises a portion of the base metal layer that is completely covered by the light-reflecting layer and the protection layer.

2. The LED of claim 1, wherein the light-reflecting layer comprises silver (Ag) or aluminum (Al).

3. The LED of claim 1, wherein the protection layer comprises gold (Au), nickel (Ni), or titanium (Ti).

4. The LED of claim 3, wherein the protection layer includes gold (Au) and is 600 nm or less thick.

5. The LED of claim 3, wherein the protection layer includes nickel (Ni) or titanium (Ti) and is 20 nm or less thick.

6. The LED of claim 1, further comprising a nickel layer arranged between the base metal layer and the light-reflecting layer.

7. The LED of claim 1, wherein the metal member comprises a slug exposing a bottom surface thereof through the housing, the slug being configured to radiate heat generated from the light-emitting chip.

8. The LED of claim 7, further comprising a lead frame configured to apply electric power to the light-emitting chip.

9. The LED of claim 1, wherein the metal member comprises a lead frame, the lead frame being configured to apply electric power to the light-emitting chip.

10. The LED of claim 9, wherein the lead frame comprises:

a first lead terminal comprising;

a chip-mounting portion on which the light-emitting chip is arranged;

a first external lead portion extended from the chip-mounting portion out of the housing; and

a first wing portion extended from the chip-mounting portion; and

a second lead terminal spaced apart from the first lead terminal, the second lead terminal comprising;

a wire bonding portion;

a second external lead portion extended from the wire bonding portion out of the housing; and

a second wing portion extended from the wire bonding portion,

wherein the first wing portion and the second wing portion are bent from the chip-mounting portion and the wire bonding portion, respectively, to be disposed at both sides of the chip-mounting portion.

11. The LED of claim 10, wherein the first wing portion extends along a side of the wire bonding portion of the second lead terminal.

12. The LED of claim 10, wherein at least one of the first wing portion and the second wing portion has a width increasing in a direction away from the chip-mounting portion.

13. The LED of claim 10, wherein the housing covers outer surfaces of the first wing portion and the second wing portion.

14. The LED of claim 10, wherein at least a portion of outer surfaces of the first wing portion and the second wing portion is exposed to an outside.

15. The LED of claim 9, wherein the lead frame comprises a first terminal and a second lead terminals that have recessed portions, respectively, the recessed portions defining a cup in which the light-emitting chip is arranged.

16. The LED of claim 15, wherein the first lead terminal and the second lead terminal each comprise wing portions that extend from the recessed portions out of the housing.

17. The LED of claim 16, wherein the first lead terminal and the second lead terminal each comprise inclined portions that connect the recessed portions with the wing portions, the inclined portions being inclined with respect to the recessed portions and the wing portions.

18. The LED of claim 9, wherein the lead frame comprises:

a first lead terminal comprising a chip-mounting portion on which the light-emitting chip is arranged, and at least one light-reflecting surface formed by being bent from the chip-mounting portion; and

a second lead terminal spaced apart from the first lead terminal.

19. The LED of claim 18, wherein the first lead terminal comprises first wing portions forming inclined surfaces by being upwardly bent from the chip-mounting portion to face each other, and the light-reflecting surface comprises the inclined surfaces formed by the first wing portions.

20. The LED of claim 19, wherein the second lead terminal comprises:

a wire bonding portion; and

second wing portions forming inclined surfaces by being upwardly bent from the wire bonding portion to face each other, the second wing portions being disposed side by side with respect to the first wing portions.

21. The LED of claim 19, wherein at least one of the first wing portions and the second wing portions has a width increasing in a direction away from the chip-mounting portion and the wire bonding portion, respectively.

22. The LED of claim 19, wherein the housing covers outer surfaces of the first wing portions and the second wing portions.

23. The LED of claim 19, wherein at least a portion of the outer surfaces of the first wing portions and the second wing portions is exposed to an outside.

24. The LED of claim 18, wherein the first lead terminal further comprises:

a step portion disposed higher than the chip-mounting portion; and

a first inclined portion connecting the step portion to the chip-mounting portion to define a light-reflecting surface.

25. The LED of claim 24, wherein the first lead terminal further comprises a second inclined portion bent from the chip-mounting portion to face the first inclined portion.

26. The LED of claim 25, wherein the first lead terminal further comprises a third inclined portion and a fourth inclined portion formed by being bent from the chip-mounting portion and disposed adjacent to the first inclined portion and the second inclined portion.

27. The LED of claim 1, further comprising a reflector formed on inner walls of the opening portion of the housing, the reflector comprising the same type of material as the metal member.

28. The LED of claim 27, wherein the reflector comprises:

a light-reflecting portion that contacts an inner surface of the opening portion of the housing; and

a heat-radiating portion that extends from the light-reflecting portion out of the housing.

29. The LED of claim 27, wherein the housing comprises a cleavage portion exposing a portion of a wire bonding region, the cleavage portion being a recessed portion of the opening portion, which is adjacent to the wire bonding region.

30. The LED of claim 1, further comprising an encapsulant disposed in the opening portion of the housing and encapsulating the light-emitting chip, the encapsulant comprising fluorescent particles distributed therein, the fluorescent particles being configured to convert a first light generated from the light-emitting chip into a second light having a different wavelength than the first light.

31. The LED of claim 30, wherein the light-emitting chip is configured to generate a blue light, and

the fluorescent particles are further configured to convert the blue light into a yellow light.

32. The LED of claim 30, wherein the light-emitting chip is configured to generate a blue light, and

the fluorescent particles comprise a first fluorescent particle configured to convert the blue light into a green light, and a second fluorescent particle configured to convert the blue light into a red light.

33. The LED of claim 30, wherein the light-emitting chip comprises a first light-emitting chip configured to generate a blue light, and a second light-emitting chip configured to generate a red light, and

the fluorescent particles being further configured to convert the blue light into a green light.

34. The LED of claim 30, wherein the light-emitting chip comprises a first light-emitting chip configured to generate a blue light, and a second light-emitting chip configured to generate a green light, and the fluorescent particles being further configured to convert the blue light or the green light into a red light.

35. The LED of claim 1, wherein the light-reflecting layer covers all surfaces of the base metal layer, and the protection layer covers all surfaces of the light-reflecting layer.