INDEPENDENT CONTROL OF LIGHT EMITTING DIODES

• US 20090310338A1
• Filed: 08/21/2009
• Published: 12/17/2009
• Est. Priority Date: 07/20/2005
• Status: Active Grant

• Current Assignee: CREE Led Incorporated (Smart Global Holdings Incorporated)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Negley, Gerald H.
• Granted Patent: US 8,328,405 B2
• Time in Patent Office: Days
• US Class Current: 362/97.100
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 3/32 semiconductive, e.g. using light-emitting diodes [LED]
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix

Abstract

A light emitting apparatus includes multiple Light Emitting Diode (LED) device controller integrated circuits and multiple LEDs of same color, but of different electrical and/or optical characteristics. A respective LED is electrically connected to a respective LED device controller integrated circuit. The respective LED may also be mounted on the respective LED device controller integrated circuit. The LED device controller integrated circuits are configured to independently control a current and/or voltage that is provided to the LED that is electrically thereto, so as to compensate for the different electrical and/or optical characteristics of the LEDs of the same color.

Claims

1. A light emitting apparatus, comprising:

a Light Emitting Diode (LED) device controller integrated circuit; and

an LED mounted on the LED device controller integrated circuit and electrically connected thereto.

2. An apparatus according to claim 1 wherein the LED is directly mounted on the LED device controller integrated circuit and electrically connected thereto.

3. An apparatus according to claim 1 wherein the LED device controller integrated circuit includes a face having a reflective cavity therein and wherein the LED is mounted in the reflective cavity.

4. An apparatus according to claim 1 wherein the LED comprises a red LED, a green LED and a blue LED mounted on the LED device controller integrated circuit and electrically connected thereto.

5. An apparatus according to claim 1 further comprising a mounting substrate, wherein the LED is mounted on a first face of the LED device controller integrated circuit and wherein a second face of the LED device controller integrated circuit that is opposite the first face is mounted on the mounting substrate.

6. An apparatus according to claim 1 wherein the LED device controller integrated circuit is configured to independently control a current and/or voltage that is provided to the LED that is mounted thereon and electrically connected thereto so as to compensate for variations in electrical and/or optical characteristics of the LED that is mounted thereon and electrically connected thereto, relative to other LEDs of same color.

7. An apparatus according to claim 1 wherein the LED device controller integrated circuit is configured to independently control a current and/or voltage that is provided to the LED that is mounted thereon and electrically connected thereto so as to provide uniform optical output of the LED that is mounted thereon and electrically connected thereto notwithstanding variations in electrical and/or optical characteristics of the LED that is mounted thereon and electrically connected thereto, relative to other LEDs of same color.

8. An apparatus according to claim 1 wherein the LED device controller integrated circuit is configured to independently control a current and/or voltage that is provided to the LED that is mounted thereon and electrically connected thereto so as to provide a uniform color point of the LED that is mounted thereon and electrically connected thereto notwithstanding the variations in electrical and/or optical characteristics of the LED that is mounted thereon and electrically connected thereto, relative to other LEDs of same color.

9. An apparatus according to claim 1 wherein the LED device controller integrated circuit is electrically connected to a common data line and is addressed via the common data line.

10. An apparatus according to claim 9 wherein the LED device controller integrated circuit is also electrically connected to a common power supply line.

11. An apparatus according to claim 1 wherein the apparatus is included in a backlight system for a flat panel color display screen that includes an array of optical shutter color picture elements.

12. A light emitting apparatus, comprising:

a plurality of Light Emitting Diode (LED) device controller integrated circuits; and

a plurality of LEDs of same color but of different electrical and/or optical characteristics, a respective LED being electrically connected to a respective LED device controller integrated circuit, a respective LED device controller integrated circuit configured to independently control a current and/or voltage that is provided to the LED of the given color that is electrically connected thereto so as to compensate for the different electrical and/or optical characteristics of the plurality of LEDs of the same color.

13. An apparatus according to claim 12 wherein the respective LED device controller integrated circuit is configured to independently control a current and/or voltage that is provided to the LED of the given color that is electrically connected thereto so as to operate the plurality of plurality of LEDs to provide uniform optical output notwithstanding the different electrical and/or optical characteristics of the plurality of LEDs of the same color.

14. An apparatus according to claim 12 wherein the respective LED device controller integrated circuit is configured to independently control a current and/or voltage that is provided to the LED of the given color that is electrically connected thereto so as to operate the plurality of plurality of LEDs to provide a uniform color point notwithstanding the different electrical and/or optical characteristics of the plurality of LEDs of the same color.

15. An apparatus according to claim 12 wherein a respective LED is also mounted on a respective LED device controller integrated circuit.

16. An apparatus according to claim 15 wherein a respective LED is also mounted directly on a respective LED device controller integrated circuit.

17. An apparatus according to claim 15 wherein a respective LED device controller integrated circuit includes a face having a reflective cavity therein and wherein a respective LED is mounted in the respective reflective cavity.

18. An apparatus according to claim 15 wherein a the plurality of LEDs comprises a plurality of red LEDs, a plurality of green LEDs and a plurality of blue LEDs, and wherein a respective red, green and blue LED is mounted on a respective LED device controller integrated circuit and electrically connected thereto.

19. An apparatus according to claim 15 further comprising a mounting substrate, wherein the a respective LED is mounted on a first face of a respective LED device controller integrated circuit and wherein a second face of a respective LED device controller integrated circuit that is opposite the first face is mounted on the mounting substrate.

20. An apparatus according to claim 12 wherein the plurality of LED device controller integrated circuits are electrically connected to a common data line and are individually addressed via the common data line.

21. An apparatus according to claim 20 wherein the plurality of LED device controller integrated circuits are also electrically connected to a common power supply line.

22. An apparatus according to claim 12 wherein the apparatus is included in a backlight system for a flat panel color display screen that includes an array of optical shutter color picture elements.

23. A light emitting apparatus, comprising:

a plurality of Light Emitting Diode (LED) device controller integrated circuits; and

a plurality of LEDs of same color but of different electrical and/or optical characteristics, a respective LED being mounted on and electrically connected to a respective LED device controller integrated circuit, a respective LED device controller integrated circuit configured to independently control a current and/or voltage that is provided to the LED of the given color that is electrically connected thereto so as to compensate for the different electrical and/or optical characteristics of the plurality of LEDs of the same color.

24. An apparatus according to claim 23 wherein the respective LED device controller integrated circuit is configured to independently control a current and/or voltage that is provided to the LED of the given color that is electrically connected thereto so as to operate the plurality of plurality of LEDs to provide uniform optical output notwithstanding the different electrical and/or optical characteristics of the plurality of LEDs of the same color.

25. An apparatus according to claim 23 wherein the respective LED device controller integrated circuit is configured to independently control a current and/or voltage that is provided to the LED of the given color that is electrically connected thereto so as to operate the plurality of plurality of LEDs to provide a uniform color point notwithstanding the different electrical and/or optical characteristics of the plurality of LEDs of the same color.

26. An apparatus according to claim 23 wherein a respective LED is mounted directly on a respective LED device controller integrated circuit.

27. An apparatus according to claim 23 wherein a respective LED device controller integrated circuit includes a face having a reflective cavity therein and wherein a respective LED is mounted in the respective reflective cavity.

28. An apparatus according to claim 23 wherein a the plurality of LEDs comprises a plurality of red LEDs, a plurality of green LEDs and a plurality of blue LEDs, and wherein a respective red, green and blue LED is mounted on a respective LED device controller integrated circuit and electrically connected thereto.

29. An apparatus according to claim 23 further comprising a mounting substrate, wherein the a respective LED is mounted on a first face of a respective LED device controller integrated circuit and wherein a second face of a respective LED device controller integrated circuit that is opposite the first face is mounted on the mounting substrate.

30. An apparatus according to claim 23 wherein the plurality of LED device controller integrated circuits are electrically connected to a common data line and are individually addressed via the common data line.

31. An apparatus according to claim 30 wherein the plurality of LED device controller integrated circuits are also electrically connected to a common power supply line.

32. An apparatus according to claim 23 wherein the apparatus is included in a backlight system for a flat panel color display screen that includes an array of optical shutter color picture elements.