Light color and intensity adjustable LED

• US 8,624,505 B2
• Filed: 05/28/2010
• Issued: 01/07/2014
• Est. Priority Date: 05/28/2010
• Status: Active Grant

• Current Assignee: Epistar Corporation (Ennostar, Inc.)
• Original Assignee: TSMC Solid State Lighting Ltd. (Ennostar, Inc.)
• Inventors: Huang, Hsin-Chieh
• Primary Examiner(s): Owens, Douglas W
• Assistant Examiner(s): PHAM, THAI N
• Application Number:
  US12/789,763
• Publication Number:
  US 20110291564A1
• Time in Patent Office: 1,320 Days
• Field of Search: 315/77, 315/118, 315149-159, 315/185.R, 315/291, 315/309
• US Class Current: 315/152
• 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 detect a light output data individually from each of the LEDs through the optical transmission line;

a controller coupled to the light detector, wherein the controller contains a memory and a logic processor, the memory storing an algorithm and a predetermined light output value, the logic processors executing the algorithm based on the detected light output data, the predetermined light output value, and a user inputted value to perform the following steps;

receiving, from the light detector, the detected light output data individually for each LED; and

comparing, for each LED, the detected light output data with one of;

an initial light output data of said LED, a light output data of said LED from a previous detection, the predetermined light output value, and the user inputted value; and

a driver coupled to the controller, wherein the driver is configured to adjust, based on a comparison result from the controller, a current for each LED such that neighboring LEDs have uniform light outputs.

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 light output data from the light detector comprises light intensity, light color, or both.

7. The device of claim 1, wherein the controller is configured to increase current for a LED when low light output is detected.

8. The device of claim 1, wherein the logic processor of the controller is configured to match light output of adjacent LEDs by adjusting a LED current.

9. The device of claim 1, wherein the logic processor of the controller is configured to match light output of groups of LEDs by adjusting current for a number of LEDs in a group.

10. 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;

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 individually detect light output values from the red LED, the blue LED, and the green LED through the optical transmission line; and

a controller coupled to the light detector and the drivers, said controller comprising a logic processor and a memory, wherein the memory stores an algorithm and a predefined targets for the red LED, the blue LED, and the green LED, and wherein the logic processor executes the algorithm based on the detected light output values, the predefined targets, and a user inputted value to individually adjust a driving current for each of the red LED, the blue LED, and the green LED, so that light outputs from the red LED, the blue LED, and the green LED each achieve the respective predefined targets or the user inputted value, and wherein the predefined targets for each LED includes one of;

an initial light output data of said LED or a light output data of said LED from a previous detection.

11. The device of claim 10, wherein the light detector comprises a photo sensor, the photo sensor is a charge-coupled device or a Complementary metal-oxide-semiconductor (CMOS) sensor, and wherein the photo sensor detects LED light intensity and color.

12. The device of claim 10, wherein the optical transmission line is multiplexed to each LED.

13. The device of claim 10, wherein the predefined targets for the red LED, the blue LED, and the green LED are different from one another.

14. The device of claim 10, wherein the logic processor of the controller is configured to execute the algorithm so as to maintain a white color intensity and a color temperature.

15. A display comprising:

a light bar comprising a first LED bank including a group of first LEDs and a backup LED bank including a group of second LEDs that are counterparts of the first LEDs, wherein one or more of the second LEDs in the backup LED bank are individually activated to replace their counterparts in the first LED bank, a driver coupled to each of the groups of first and second LEDs, 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 individually detect a light output data from each of the first LEDs in the first LED bank through the optical transmission line; and

a controller coupled to the light detector and the driver, said controller comprising a logic processor and a memory, the memory storing an algorithm and a predefined light output value, wherein the logic processor executes the algorithm based on the detected light output data, the predefined light output value, and a user inputted value to adjust LED light intensity or light color.

16. A method comprising:

measuring a light intensity of a plurality of LEDs, wherein the light intensity of each LED is measured individually;

storing a predefined light output value in an electronic memory;

receiving a user-defined light output value from a user input device;

comparing the measured light intensity from each of the plurality of LEDs, wherein the comparing comprises individually comparing, for each LED, the measured light intensity with one of;

an initial light intensity of said LED, a light intensity for said LED from a previous measurement, the predefined light output value, or the user-defined light output value;

adjusting, in response to the comparing, a current for each LED in at least a subset of the plurality of LEDs such that the light intensity from neighboring LEDs become uniform with one another.

17. The method of claim 16, wherein the current for a selected subset of the plurality of LEDs that have lower light intensity than a remainder of the plurality of LEDs is increased.

18. The method of claim 16, wherein the current for a selected subset of the plurality of LEDs that have higher light intensity than a remainder of the plurality of LEDs is decreased.

19. The method of claim 16, wherein the plurality of LEDs are from a first LED bank, and further comprising:

activating one or more LEDs from a backup LED bank to replace their counterpart LEDs in the first LED bank.

20. The method of claim 16, wherein the current for the subset of the plurality of LEDs is adjusted such that a sum of the light intensity for the subset of the plurality of LEDs is substantially equal to a sum of the light intensity for a remainder of the plurality of LEDs.