Light emitting diode based light system with a redundant light source

• US 20050242742A1
• Filed: 04/30/2004
• Published: 11/03/2005
• Est. Priority Date: 04/30/2004
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies ECBU IP Singapore Pte Limited (Broadcom, Inc.)
• Inventors: Ng, Fook Chuin, Ko, Choon Guan, Cheang, Tak Meng, Chew, Choon Keat
• Granted Patent: US 7,012,382 B2
• Time in Patent Office: Days
• US Class Current: 315/149
• CPC Class Codes: H05B 45/20 Controlling the colour of the light
• CPC Class Codes: H05B 45/22 using optical feedback

Abstract

An LED-based light system includes a primary light source and at least one redundant light source. The primary light source is activated by itself and the performance of the light source is measured to determine whether nor not to drive the redundant light source. The redundant light source is activated when the performance measurements indicate that a performance characteristic is not being met by the primary light source alone. The first light system can be activated in combination with the redundant light source once the decision is made to activate the redundant light source.

Claims

1. A method for controlling a light emitting diode (LED) based light system comprising:

activating a first light source of an LED-based light system that includes a redundant light source;

generating feedback signals related to the first light source; and

determining whether to activate the redundant light source of the LED-based light system in response to the feedback signals.

2. The method of claim 1 further including activating the redundant light source if the feedback signals indicate that a performance characteristic is not being met by the first light source alone.

3. The method of claim 2 wherein the performance characteristic includes at least one of color point and brightness.

4. The method of claim 1 wherein generating feedback signals includes measuring the color point of light emitted by the first light source.

5. The method of claim 1 wherein generating feedback signals includes measuring the brightness of light emitted by the first light source.

6. The method of claim 1 further including activating the redundant light source in addition to the first light source if the feedback signals indicate that a performance characteristic is not being met by the first light source alone.

7. The method of claim 6 wherein the first light source and the redundant light source are activated with the same LED control signals.

8. A light emitting diode (LED) based light system comprising:

a first light source;

a redundant light source;

means, in optical signal communication with the first light source and electrical signal communication with the first and the redundant light sources, for;

activating the first light source;

generating feedback signals related to the first light source; and

determining whether to activate the redundant light source in response to the feedback signals.

9. The LED-based light system of claim 8 wherein the means for activating, generating, and determining further includes means for activating the redundant light source if the feedback signals indicate that a performance characteristic is not being met by the first light source alone.

10. The LED-based light system of claim 9 wherein generating feedback signals includes measuring at least one of color point and brightness.

11. The LED-based light system of claim 8 wherein generating feedback signals includes measuring the color point of light emitted by the first light source.

12. The LED-based light system of claim 8 wherein generating feedback signals includes measuring the brightness of light emitted by the first light source.

13. The LED-based light system of claim 8 wherein the means for activating, generating, and determining further includes means for activating the redundant light source in addition to the first light source if the feedback signals indicate that a performance characteristic is not being met by the first light source alone.

14. The LED-based light system of claim 13 wherein the means for activating, generating, and determining further includes means for activating the redundant light source with the same LED control signals that are used to activate the first light source.

15. The LED-based light system of claim 8 wherein the means for determining includes a control system and a switch system, the control system being configured to receive the feedback signals related to the first light source and to provide a switch control signal to the switch system, the switch system configured to provide LED control signals to the redundant light source in response to the switch control signal from the control system.

16. A light emitting diode (LED) based light system comprising:

a first light source;

a redundant light source;

a redundant light source management system in optical signal and electrical signal communication with the first and the redundant light sources, the redundant light source management system configured to activate the first light source, to generate feedback signals related to the first light source, and to determine whether to activate the redundant light source in response to the feedback signals.

17. The LED-based light system of claim 16 wherein the redundant light source management system is further configured to activate the redundant light source if the performance characteristic measurement indicates that the performance characteristic is not being met by the first light source alone.

18. The LED-based light system of claim 16 wherein the redundant light source management system includes a control system and a switch system, the control system being configured to receive the feedback signals related to the first light source and to provide a switch control signal to the switch system, the switch system configured to provide LED control signals to the redundant light source in response to the switch control signal from the control system.

19. The LED-based light system of claim 16 wherein the redundant light source management system includes a switch that is configured to allow LED control signals to the redundant light source if the feedback signals indicate that a performance characteristic is not being met by the first light source alone.

20. The LED-based light system of claim 19 wherein the redundant light source management system includes a color sensor, a color management system, and a microcontroller, the color sensor configured to detect light emitted from the first light source and to provide the feedback signals to the color management system, the color management system configured to compare luminance and chrominance characteristics indicated by the feedback signals to luminance and chrominance reference values and to output an indication of the comparison to the microcontroller, the microcontroller configured to control the switch in response to the output from the color management system.