LIGHT COLOR AND INTENSITY ADJUSTABLE LED

• US 20110291564A1
• Filed: 05/28/2010
• Published: 12/01/2011
• Est. Priority Date: 05/28/2010
• Status: Active Grant

• Current Assignee: Epistar Corporation
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: HUANG, Hsin-Chieh
• Granted Patent: US 8,624,505 B2
• Time in Patent Office: Days
• US Class Current: 315/77
• 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 integrated photonic device comprising:

a plurality of light emitting diodes (LEDs);

an optical transmission line coupled to the LEDs;

a light detector coupled to the optical transmission line and configured to receive light generated at each of the LEDs through the optical transmission line; and

a driver coupled to the LEDs and the light detector, said driver configured to receive light output data from the light detector for each LED and drive current at each LED using said data.

2. The device of claim 1, wherein the light detector comprises a photo sensor, the photo sensor being a charge-coupled device or a Complementary Metal-Oxide-Semiconductor (CMOS) sensor.

3. The device of claim 1, wherein the optical transmission line is an optical fiber or a light pipe.

4. The device of claim 1, wherein the optical transmission line includes multiple branches ending at separate LEDs.

5. The device of claim 1, wherein the light detector further comprises optical transmission lines such that light received from each of the LEDs are transmitted separately.

6. The device of claim 1, wherein the data from the light detector comprises light intensity, light color, or both.

7. The device of claim 1, wherein the driver comprises a current generator and a controller.

8. The device of claim 7, wherein the controller is configured to increase current for a LED when low light output is detected.

9. The device of claim 7, wherein the controller comprises logic and memory, said logic is configured to match light output of adjacent LEDs by adjusting a LED current.

10. The device of claim 7, wherein the controller comprises logic and memory, said logic is configured to match light output of groups of LEDs by adjusting current for a number of LEDs in a group.

11. An integrated photonic device comprising:

a light emitting device having a red LED, a blue LED, and a green LED;

a driver coupled to each LED, said driver comprising a current generator;

an optical transmission line coupled to the light emitting device and configured to transmit a portion of light generated by each LED;

a light detector coupled to the optical transmission line and configured to receive light through the optical transmission line; and

a controller coupled to the light detector and the drivers, said controller comprising logic and memory.

12. The device of claim 11, wherein the light detector comprises a photo sensor, the photo sensor is a charge-coupled device or a Complementary metal-oxide-semiconductor (CMOS) sensor.

13. The device of claim 11, wherein the optical transmission line is multiplexed to each LED.

14. The device of claim 11, wherein the photo sensor detects LED light intensity and color.

15. The device of claim 11, wherein the controller logic is configured to maintain a white color intensity and temperature.

16. A display comprising:

a light bar comprising a plurality of LEDs, a driver coupled to each LED, said driver comprising a current generator, and an optical transmission line disposed to transmit a portion of light generated by each LED; and

,

a light detector coupled to the optical transmission line and configured to receive light through the optical transmission line; and

,

a controller coupled to the light detector and the driver, said controller comprising logic and memory, wherein the controller logic is configured to adjust LED light intensity or color.

17. A method comprising:

measuring a light intensity of a plurality of LEDs;

comparing the measured light intensities;

adjusting a current for a subset of the plurality of LEDs to improve light intensity distribution among the plurality of LEDs.

18. The method of claim 17, wherein the current for a subset of the plurality of LEDs that have lower light intensity than a remainder of the plurality of LEDs is increased.

19. The method of claim 17, wherein the current for a subset of the plurality of LEDs that have higher light intensity than a remainder of the plurality of LEDs is decreased.

20. The method of claim 17, wherein the current for a subset of the plurality of LEDs that have higher light intensity than a remainder of the plurality of LEDs is decreased and the current for a subset of the plurality of LEDs that have higher light intensity than a remainder of the plurality of LEDs is decreased.

21. The method of claim 17, wherein the current for a subset of the plurality of LEDs is adjusted such that a sum of light intensities for the subset of the plurality of LEDs is substantially equal to a sum of light intensities for a remainder of the plurality of LEDs.

23. The method of claim 21, wherein the warning is a sound or a light.

22. A method comprising:

measuring a light intensity of each of a plurality of LEDs mounted on an exterior of a vehicle;

comparing each of the measured light intensity to a specified baseline; and

issuing a warning if a specified amount of the measured light intensities are below a specified baseline.

24. A LED light fixture comprising:

a plurality of light emitting diodes (LEDs);

one or more optical transmission lines coupled to the LEDs;

a light detector coupled to the one or more optical transmission lines and configured to receive light through the optical transmission line;

a driver coupled to the LEDs and the light detector, said driver comprises a current generator;

a dimmer switch having one or more dimmed positions; and

a controller coupled to the driver and the light detector, said controller configured to adjust the current generated such that a total light detected equals to a specified value corresponding to a dimmed position when the dimmer switch is set on the dimmed position.