Method for operating a light emitting diode arrangement, method for characterizing a light emitting diode, and light emitting diode arrangement

Patent metadata

Field	Value
Publication number	US-11985740-B2
Application number	US-202017612896-A
Country	US
Kind code	B2
Filing date	Jun 4, 2020
Priority date	Jun 11, 2019
Publication date	May 14, 2024
Grant date	May 14, 2024

Abstract

A method for operating a light emitting diode arrangement with at least one light emitting diode includes the steps of: a) determining at least one instantaneous current-voltage value pair; b) matching the instantaneous current-voltage value pair with an original current-voltage value pair; and c) determining an updated current feed based on the matching and driving the light emitting diode with the updated current feed.

First claim

The invention claimed is:

1. A method for characterizing a light-emitting diode with regard to its internal efficiency of light generation with the steps:
a) determining current-voltage value pairs for the light-emitting diode;
b) approximating the current-voltage value pairs based on a current-voltage curve of an equivalent circuit in which an ideal radiating diode is bridged by a parallel branch, the parallel branch comprising a parasitic non-radiating diode and a series resistor, wherein a resistance of the series resistor is used as a parameter for the approximation; and
c) matching the resistance of the series resistor obtained by the approximation with a characteristic resistance of the series resistor for the light emitting diode to obtain information about the internal efficiency of light generation.

2. The method according to claim 1 ,
in which the light-emitting diode is selected out if a deviation of the series resistor from the characteristic series resistor exceeds a specified tolerance value.

3. A light-emitting diode arrangement with at least one light-emitting diode and a drive circuit, wherein
the light-emitting diode arrangement is configured to determine an instantaneous current-voltage value pair of the light-emitting diode and to determine an updated current feed for the light-emitting diode on the basis of the instantaneous current-voltage value pair,
an updated efficiency of the light emitting diode is determined for different dimming levels based on the deviation between the instantaneous current-voltage value pair and the original current-voltage value pair, and
the determination of the updated efficiency of the light-emitting diode is based on an equivalent circuit in which an ideal radiating diode is bridged by a parallel branch, the parallel branch comprising a parasitic non-radiating diode and a series resistor.

4. The light emitting diode arrangement according to claim 3 , wherein the light emitting diode arrangement is a display device with a plurality of light emitting diodes, wherein the light emitting diode arrangement is configured to determine an instantaneous current-voltage value pair for each of the light emitting diodes and to determine an updated current feed for the light emitting diodes based on the respective instantaneous current-voltage value pairs.

5. The light emitting diode arrangement according to claim 3 , wherein the light-emitting diode arrangement comprises a memory in which characteristic values for the light-emitting diode are stored for its original current-voltage characteristic.

6. The light-emitting diode arrangement according to claim 3 , wherein the light-emitting diode arrangement comprises a memory in which a plurality of original current-voltage value pairs are stored for the light-emitting diode.

7. The light emitting diode arrangement according to claim 3 , wherein the light emitting diode arrangement can be calibrated on the basis of an original current-voltage characteristic.

8. A method for operating a light emitting diode arrangement with at least one light emitting diode comprising the steps:
a) determining at least one instantaneous current-voltage value pair;
b) matching the instantaneous current-voltage value pair with an original current-voltage value pair; and
c) determining an updated current feed based on the matching and driving the light emitting diode with the updated current feed;
wherein
an updated efficiency of the light emitting diode is determined for different dimming levels based on the deviation between the instantaneous current-voltage value pair and the original current-voltage value pair, and
the determination of the updated efficiency of the light-emitting diode is based on an equivalent circuit in which an ideal radiating diode is bridged by a parallel branch, the parallel branch comprising a parasitic non-radiating diode and a series resistor.

9. The method of claim 8 ,
wherein aging of the light emitting diode is at least partially compensated for by determining the updated current feed.

10. The method of claim 8 ,
wherein the light emitting diode arrangement comprises at least one further light emitting diode and wherein an updated current feed is determined for the further light emitting diode on the basis of an individually determined instantaneous current-voltage value pair.

11. The method of claim 8 ,
wherein a current is in the low current regime of the light emitting diode when the instantaneous current-voltage value pair is determined.

12. The method of claim 8 ,
wherein the light emitting diode arrangement is configured to operate the light emitting diode with a plurality of dimming levels, and an associated updated current feed is determined for each dimming level.

13. The method of claim 8 ,
wherein an updated series resistor is determined based on the instantaneous current-voltage value pair, and the updated current feed is determined based on the updated series resistor.

14. The method of claim 8 ,
wherein a respective instantaneous current-voltage-value pair is determined for a plurality of dimming levels, and a correspondingly updated current feed for the dimming level is determined for the dimming levels on the basis of the respective associated instantaneous current-voltage value pair.

Assignees

• Osram Opto Semiconductors Gmbh

Inventors

• Binder Michael
• Specht Holger
• Tauer Maximilian

Classifications

• H05B45/14 Primary

  using electrical feedback from LEDs or from LED modules · CPC title

• H05B45/58

  involving end of life detection of LEDs · CPC title

• H05B45/10 Primary

  Controlling the intensity of the light · CPC title