LED package structure with a fuse for protection from high current

• US 8,552,450 B2
• Filed: 07/28/2011
• Issued: 10/08/2013
• Est. Priority Date: 05/27/2009
• Status: Expired due to Fees

• Current Assignee: Everlight Electronics Company Limited
• Original Assignee: Everlight Electronics Company Limited
• Inventors: Weng, Ssu-Yuan
• Primary Examiner(s): Jahan, Bilkis
• Application Number:
  US13/192,988
• Publication Number:
  US 20110278639A1
• Time in Patent Office: 803 Days
• Field of Search: 257 98-100, 257/209, 257/528, 257/529, 257/665, 438/132, 438/215, 438/281, 438/333, 438/467, 438/601
• US Class Current: 257/98
• CPC Class Codes: H01L 2224/45144 Gold (Au) as principal constituent
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48137 the bodies being arranged next to each other, e.g. on a common substrate
• CPC Class Codes: H01L 2224/48195 the item being a discrete passive component
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48257 connecting the wire to a die pad of the item
• CPC Class Codes: H01L 23/3121 a substrate forming part of the encapsulation
• CPC Class Codes: H01L 23/62 Protection against overvoltage, e.g. fuses, shunts
• CPC Class Codes: H01L 24/45 of an individual wire connector
• CPC Class Codes: H01L 24/48 of an individual wire connector
• CPC Class Codes: H01L 25/167 comprising optoelectronic devices, e.g. LED, photodiodes
• 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 2924/00012 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 2924/01014 Silicon [Si]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/12041 LED
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 2924/3011 Impedance
• CPC Class Codes: H01L 33/483 Containers

Abstract

An LED package structure comprises an LED chip and a fuse electrically connected to the LED chip in series. The fuse has a low melting point such that the fuse melts under a high current to form an open circuit to prevent the high current from flowing through the LED chip.

Claims

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

an LED chip; and

a fuse electrically connected to the LED chip in series, the fuse alternatively changing between being electrically conductive and being electrically non-conductive depending on a temperature of the fuse; and

a lead frame having a first lead pin, a second lead pin, and a loading part connected to the first lead pin;

the LED chip is disposed on the loading part of the lead frame, wherein the loading part has a triangular profile when viewed from a side, and wherein the fuse is disposed on the first lead pin of the lead frame.

2. The LED package structure of claim 1, wherein the fuse comprises a resettable fuse.

3. The LED package structure of claim 2, wherein the resettable fuse comprises two electrodes and a conductive polymer layer sandwiched between the two electrodes.

4. The LED package structure of claim 1, further comprising:

a plurality of metal conductive wires that electrically connect the LED chip and the fuse in series between the first lead pin and the second lead pin of the lead frame.

11. The LED package structure of claim 3, wherein the resettable fuse conducts electrical current at a first temperature, and wherein a polymer chain scission forms in the conductive polymer layer at a second temperature higher than the first temperature such that the resettable fuse transforms from being electrically conductive to electrically non-conductive.

12. The LED package structure of claim 1, wherein the fuse changes from being electrically conductive when the fuse is at a first temperature to being electrically non-conductive when the fuse is at a second temperature higher than the first temperature, and further changes from being electrically non-conductive to being electrically conductive when the fuse is cooled down to a temperature lower than the second temperature.

5. A light emitting diode (LED) package structure, comprising:

a lead frame having a first lead pin, a second lead pin, and a loading part connected to the first lead pin;

an LED chip disposed on the lead frame; and

a fuse disposed on the lead frame and electrically connected to the LED chip in series between the first lead pin and the second lead pin of the lead frame, the fuse alternatively changing between being electrically conductive and being electrically non-conductive depending on a temperature of the fuse; and

the LED chip is disposed on the loading part of the lead frame, wherein the loading part has a triangular profile when viewed from a side, and wherein the fuse is disposed on the first lead pin of the lead frame.

6. The LED package structure of claim 5, wherein the fuse comprises a resettable fuse.

7. The LED package structure of claim 6, wherein the resettable fuse comprises two electrodes and a conductive polymer layer sandwiched between the two electrodes.

8. The LED package structure of claim 7, wherein the resettable fuse conducts electrical current at a first temperature, and wherein a polymer chain scission forms in the conductive polymer layer at a second temperature higher than the first temperature such that the resettable fuse transforms from being electrically conductive to electrically non-conductive.

9. The LED package structure of claim 5, further comprising:

a plurality of metal conductive wires that electrically connect the LED chip and the fuse in series between the first lead pin and the second lead pin of the lead frame.

10. The LED package structure of claim 5, further comprising:

an encapsulation covering the LED chip, the fuse, and at least a part of the lead frame.