Light color and intensity adjustable LED

• US 8,884,529 B2
• Filed: 11/13/2013
• Issued: 11/11/2014
• Est. Priority Date: 05/28/2010
• Status: Active Grant

• Current Assignee: Epistar Corporation
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Huang, Hsin-Chieh
• Primary Examiner(s): Owens, Douglas W
• Assistant Examiner(s): PHAM, THAI N
• Application Number:
  US14/078,631
• Publication Number:
  US 20140055039A1
• Time in Patent Office: 363 Days
• Field of Search: 315/77, 315/118, 315149-159, 315/185.R, 315/291, 315/309
• US Class Current: 315/151
• 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 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H05B 45/12 using optical feedback
• CPC Class Codes: H05B 45/22 using optical feedback

Abstract

An integrated photonic device includes a number of LEDs and a feedback mechanism that measures individual LED light outputs using a photo sensor via a light transmitter disposed in the vicinity of individual LEDs. A controller or driver adjusts a current driven to each LED using the detected values according to various logic based on the device application.

Claims

1. An apparatus, comprising:

a first light-emitting diode (LED) assembly that includes a plurality of first LEDs;

a second light-emitting diode (LED) assembly that includes a plurality of second LEDs;

a first driver coupled to the first LED assembly;

a second driver coupled to the second LED assembly;

a light detector coupled to each of the first and second LED assemblies, wherein the light detector is configured to measure a first light output of the first LED assembly and a second light output of the second LED assembly; and

a controller coupled to the light detector and to each of the first and second drivers, wherein the controller is configured to;

receive the first light output and the second light output from the light detector;

compare the first light output with the second light output; and

upon detecting a difference between the first light output and the second light output, control the first and second drivers to reduce a difference between the first light output and the second light output.

2. The apparatus of claim 1, further comprising:

a first optical transmission line coupled between the first LED assembly and the light detector; and

a second optical transmission line coupled between the second LED assembly and the light detector;

wherein the light detector measures the first and second light outputs through the first and second optical transmission lines, respectively.

3. The apparatus of claim 1, wherein the first LEDs and the second LEDs each include a red LED, a green LED, and a blue LED.

4. The apparatus of claim 1, wherein the first and second LED assemblies are individual image pixels.

5. The apparatus of claim 1, wherein the first and second LED assemblies are light bar modules in a backlight unit of a television.

6. The apparatus of claim 1, wherein at least one of the light detector and the controller includes an analog-to-digital converter.

7. The apparatus of claim 1, wherein the controller is also configured to control the first and second drivers to reduce differences between light intensities of individual LEDs of the first LED assembly and the second LED assembly.

8. The apparatus of claim 1, wherein the first and second LED assemblies are electrically coupled in parallel.

9. A method, comprising:

providing a first light-emitting diode (LED) assembly that includes a plurality of first LEDs;

providing a second light-emitting diode (LED) assembly that includes a plurality of second LEDs;

providing a first driver coupled to the first LED assembly;

providing a second driver coupled to the second LED assembly;

measuring a first light output of the first LED assembly and measuring a second light output of the second LED assembly; and

comparing the first light output with the second light output; and

operating, based on results of the comparing, the first and second drivers to minimize a difference between the first light output and the second light output.

10. The method of claim 9, wherein the measuring is performed by a light detector that is electrically coupled to each of the first and second LED assemblies.

11. The method of claim 10, wherein the light detector includes an analog-to-digital converter.

12. The method of claim 10, wherein the measuring comprises:

measuring the first light output using a first optical transmission line coupled between the first LED assembly and the light detector; and

measuring the second light output using a second optical transmission line coupled between the second LED assembly and the light detector.

13. The method of claim 9, wherein the operating is performed by a controller that is electrically coupled to each of the first and second LED drivers.

14. The method of claim 9, wherein the first LEDs and the second LEDs each include a red LED, a green LED, and a blue LED, respectively.

15. The method of claim 9, wherein the first and second LED assemblies are individual image pixels.

16. The method of claim 9, wherein the first and second LED assemblies are light bar modules in a backlight unit of a television.

17. The method of claim 9, wherein the operating the first and second drivers is performed such that light intensities of individual LEDs of the first LED assembly and the second LED assembly approach uniformity.

18. The method of claim 9, wherein the first and second LED assemblies are electrically coupled in parallel.

19. An apparatus, comprising:

a first light-emitting diode (LED) assembly that includes a first red LED, first green LED, and a first blue LED;

a second light-emitting diode (LED) assembly that includes a second red LED, a second green LED, and a second blue LED, wherein the first and second LED assemblies are electrically coupled in parallel;

a first driver coupled to the first LED assembly;

a second driver coupled to the second LED assembly;

a light detector coupled to each of the first and second LED assemblies through first and second optical transmission lines, respectively, wherein the light detector is configured to measure a first light output of the first LED assembly and a second light output of the second LED assembly; and

a controller coupled to the light detector and to each of the first and second drivers, wherein the controller is configured to;

receive the first light output and the second light output from the light detector;

compare the first light output with the second light output; and

operate the first and second drivers to reduce differences between the first light output and the second light output.

20. The apparatus of claim 19, wherein the controller is also configured to control the first and second drivers such that light intensities of individual LEDs of the first LED assembly and the second LED assembly become substantially uniform with one another.