LED-BASED ILLUMINATION MODULE ON-BOARD DIAGNOSTICS

• US 20110254554A1
• Filed: 06/15/2011
• Published: 10/20/2011
• Est. Priority Date: 06/18/2010
• Status: Active Grant

• Current Assignee: SBC Xicato Corporation
• Original Assignee: Xicato, Inc.
• Inventors: Harbers, Gerard
• Granted Patent: US 8,519,714 B2
• Time in Patent Office: Days
• US Class Current: 324/414
• CPC Class Codes: F21V 23/0457 the sensor sensing the operating status of the lighting device, e.g. to detect failure of a light source or to provide feedback to the device
• CPC Class Codes: F21Y 2113/13 comprising an assembly of point-like light sources
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G01K 11/00 Measuring temperature based upon physical or chemical changes not covered by groups G01K3/00, G01K5/00, G01K7/00 or G01K9/00
• CPC Class Codes: H05B 45/48 having LEDs organised in strings and incorporating parallel shunting devices
• CPC Class Codes: H05B 45/58 involving end of life detection of LEDs
• CPC Class Codes: H05B 47/105 in response to determined parameters
• CPC Class Codes: H05B 47/11 by determining the brightness or colour temperature of ambient light
• CPC Class Codes: H05B 47/19 via wireless transmission
• CPC Class Codes: H05B 47/20 Responsive to malfunctions or to light source life; for protection
• CPC Class Codes: H05B 47/22 with communication between the lamps and a central unit
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

A light emitting diode (LED) based illumination module performs on-board diagnostics. For example, diagnostics may include estimating elapsed lifetime, degradation of phosphor, thermal failure, failure of LEDs, or LED current adjustment based on measured flux or temperature. The elapsed lifetime may be estimated by scaling accumulated elapsed time of operation by an acceleration factor derived from actual operating conditions, such as temperature, current and relative humidity. The degradation of phosphor may be estimated based on a measured response of the phosphor to pulsed light from the LEDs. A thermal failure may be diagnosed using a transient response of the module from a start up condition. The failure of LEDs may be diagnosed based on measured forward voltage. The current for LEDs may adjusted using measured flux values and current values and a desired ratio of flux values. Additionally, the LED current may be scaled based on a measured temperature.

Claims

1. A method comprising:

determining an incremental acceleration factor for a period of time of operation of an LED based illumination module based on a nominal value of an operating condition and an actual value of the operating condition;

determining a cumulative acceleration factor based at least in part on the incremental acceleration factor; and

estimating an elapsed lifetime of the LED based illumination module based on scaling an accumulated elapsed time of operation of the LED based illumination module with the cumulative acceleration factor.

2. The method of claim 1, wherein the operating condition is taken from a group consisting of:

temperature, current, and relative humidity.

3. The method of claim 1, wherein the incremental acceleration factor is one of a plurality of incremental acceleration factors, and wherein each of the plurality of incremental acceleration factors is determined over a different period of time of operation of the LED based illumination module.

4. The method of claim 3, wherein the determining of the cumulative acceleration factor includes averaging the plurality of incremental acceleration factors.

5. The method of claim 1, wherein the estimating of claim 1 is performed by a processor of the LED based illumination module.

6. The method of claim 1, wherein the accumulated elapsed time of operation of the LED based illumination module is determined by the LED based illumination module.

7. The method of claim 1, further comprising:

comparing the elapsed lifetime of the LED based illumination module with a predetermined threshold value; and

communicating an alarm if the elapsed lifetime of the LED based illumination module exceeds the predetermined threshold value.

8. The method of claim 1, further comprising:

comparing the elapsed lifetime of the LED based illumination module with a predetermined threshold value; and

shutting down the LED based illumination module if the elapsed lifetime of the LED based illumination module exceeds the predetermined threshold value.

9. The method of claim 1, further comprising:

comparing the elapsed lifetime of the LED based illumination module with a predetermined threshold value; and

requesting a code value if the elapsed lifetime of the LED based illumination module exceeds the predetermined threshold value.

10. A method comprising:

determining an accumulated elapsed lifetime of an LED based illumination module;

determining a difference between the accumulated elapsed lifetime and a first target lifetime value;

determining an estimated remaining lifetime;

generating an extended lifetime offer based at least in part on the difference between the accumulated elapsed lifetime and the first target lifetime value and the estimated remaining lifetime.

11. The method of claim 10, further comprising:

communicating the extended lifetime offer to an entity; and

receiving acceptance of the extended lifetime offer from the entity.

12. The method of claim 11, further comprising:

communicating a message to the LED based illumination module authorizing the LED based illumination module to operate for an extended lifetime period.

13. The method of claim 12, wherein the message authorizing the LED based illumination module to operate for the extended lifetime period includes a second target lifetime value.

14. The method of claim 10, wherein the determining the estimated remaining lifetime involves,

determining an incremental acceleration factor for a period of time of operation of the LED based illumination module based on a nominal value of an operating condition and an actual value of the operating condition,

determining a cumulative acceleration factor based at least in part on the incremental acceleration factor, and

estimating an elapsed lifetime of the LED based illumination module based on scaling an accumulated elapsed time of operation of the LED based illumination module with the cumulative acceleration factor.

15. A method comprising:

determining an accumulated elapsed lifetime of an LED based illumination module;

determining an estimated elapsed lifetime of the LED based illumination module; and

generating an extended lifetime offer based at least in part on a difference between the accumulated elapsed lifetime and the estimated elapsed lifetime of the LED based illumination module.

16. The method of claim 15, further comprising:

communicating the extended lifetime offer to an entity; and

receiving acceptance of the extended lifetime offer from the entity.

17. The method of claim 16, further comprising:

communicating a message to the LED based illumination module authorizing the LED based illumination module to operate for an extended lifetime period.

18. The method of claim 17, wherein the message authorizing the LED based illumination module to operate for the extended lifetime period includes a target lifetime value.

19. The method of claim 18, wherein the message authorizing the LED based illumination module to operate for the extended lifetime period includes an unlock code.

20. The method of claim 15, wherein the determining the estimated elapsed lifetime involves,

determining an incremental acceleration factor for a period of time of operation of the LED based illumination module based on a nominal value of an operating condition and an actual value of the operating condition,

determining a cumulative acceleration factor based at least in part on the incremental acceleration factor, and

estimating an elapsed lifetime of the LED based illumination module based on scaling an accumulated elapsed time of operation of the LED based illumination module with the cumulative acceleration factor.