Operating system and method of light emitting device

• US 8,358,257 B2
• Filed: 08/09/2007
• Issued: 01/22/2013
• Est. Priority Date: 08/10/2006
• Status: Expired due to Fees

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: LG Electronics, Inc. (LG Corporation)
• Inventors: Park, Jun Sung
• Primary Examiner(s): Wang, Quan-Zhen
• Assistant Examiner(s): DAVIS, TONY O
• Application Number:
  US11/836,625
• Publication Number:
  US 20080036713A1
• Time in Patent Office: 1,993 Days
• Field of Search: 385/92, 362/264, 713/500, 345/82
• US Class Current: 345/82
• 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 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H05B 45/18 using temperature feedback

Abstract

An operating system for estimating thermal property of a light emitting device to operate the light emitting device, and an operating method thereof are disclosed. The operating system of a light emitting device includes a light emitting device package and a driving unit to drive the light emitting device package at frequency equal to or higher than 100 Hz.

Claims

1. An operating system of a light emitting device comprising:

a light emitting diode package comprising;

a light emitting diode chip; and

a heat sink thermally connected to the light emitting diode chip, the heat sink comprising a metal; and

a driving unit to drive the light emitting diode package at frequency equal to or higher than 100 Hz, the driving unit performing a duty operation,

wherein the frequency is configured to decrease an operational temperature of the light emitting diode chip, and wherein the driving unit is configured to estimate a junction temperature of the light emitting diode chip within 10% of an error range, and

wherein the junction temperature T of the light emitting diode chips is estimated by a formula, T=T_a+(R_{LED package}+R_{external heat sin k})×

W×

duty, where T_a is ambient temperature, R is thermal resistance, and W is heat discharge of the light emitting diode chips.

2. The operating system of a light emitting device according to claim 1, further comprising a solder ball, and an epoxy positioned between the light emitting diode chip and the heat sink.

3. The operating system of a light emitting device according to claim 1, further comprising an encapsulant and a lens disposed in the upper side of the light emitting diode chip.

4. The operating system of a light emitting device according to claim 1, wherein the light emitting diode chip comprises one of light emitting diode chips based on GaAs, InP, InGaP, and GaN.

5. The operating system of a light emitting device according to claim 1, wherein the driving unit drives the light emitting diode package at frequency equal to or less than 2 KHz.

6. The operating system of a light emitting device according to claim 1, wherein the number of the light emitting diode package is plural.

7. The operating system of a light emitting device according to claim 6, wherein the light emitting diode packages are arranged in a panel having a predetermined area.

8. The operating system of a light emitting device according to claim 1, wherein the junction temperature of the light emitting diode chip is estimated by thermal resistance of the light emitting diode package or the heat sink.

9. An operating system of a light emitting device comprising:

a plurality of light emitting diode chips;

a heat sink thermally connected to the plurality of light emitting diode chips, the heat sink comprising a metal; and

a driving unit to drive the light emitting diode chips at frequency equal to or higher than 100 Hz, the driving unit performing a duty operation,

wherein the frequency is configured to decrease an operational temperature of the light emitting diode chips, and wherein the driving unit is configured to estimate a junction temperature of the light emitting diode chips within 10% of an error range, and

wherein the junction temperature T of the light emitting diode chips is estimated by a formula, T=T_a+(R_{LED package}+R_{external heat sin k})×

W×

duty, where T_a is ambient temperature, R is thermal resistance, and W is heat discharge of the light emitting diode chips.

10. The operating system of a light emitting device according to claim 9, wherein the plural light emitting diode chips emit full colored light.

11. The operating system of a light emitting device according to claim 9, wherein the driving unit the light emitting diode chips at frequency equal to or less than 2 KHz.

12. The operating system of a light emitting device according to claim 9, wherein each of the light emitting diode chips comprises one of light emitting based on GaAs, InP, InGaP, and GaN.

13. The operating system of a light emitting device according to claim 9, wherein the junction temperature of the light emitting diode chips is estimated by thermal resistance of the heat sink.

14. A method of driving a light emitting device comprising at least one light emitting diode package, comprising:

driving the light emitting diode package at frequency equal to or higher than 100 Hz, by performing a duty operation, wherein the light emitting diode package comprises a light emitting diode chip and a heat sink thermally connected to the light emitting diode chip,

wherein the heat sink comprises a metal, wherein the frequency is configured to decrease an operational temperature of the light emitting diode chip,

wherein the driving unit is configured to estimate a junction temperature of the light emitting diode chip within 10% of an error range, and

wherein the junction temperature T of the light emitting diode chips is estimated by a formula, T=T_a+(R_{LED package}+R_{external heat sin k})×

W×

duty, where T_a is ambient temperature, R is thermal resistance, and W is heat discharge of the light emitting diode chips.

15. The method of driving a light emitting device according to claim 14, wherein the frequency is equal to or less than 2 KHz.

16. The method of driving a light emitting device according to claim 14, wherein the junction temperature of the light emitting diode chip is estimated by thermal resistance of the light emitting diode package or the heat sink.