Independent control of light emitting diodes

• US 8,328,405 B2
• Filed: 08/21/2009
• Issued: 12/11/2012
• 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.
• Primary Examiner(s): CARTER, WILLIAM JOSEPH
• Application Number:
  US12/545,600
• Publication Number:
  US 20090310338A1
• Time in Patent Office: 1,208 Days
• Field of Search: 362459-549, 362/800
• US Class Current: 362/612
• 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 microchip that includes an LED device driver; and

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

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

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

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

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

6. An apparatus according to claim 1 wherein the LED device controller integrated circuit microchip is configured to independently control a current and/or voltage that is provided to the LED that is mounted directly thereon and electrically connected thereto so as to provide uniform optical output of the LED that is mounted directly thereon and electrically connected thereto notwithstanding variations in electrical and/or optical characteristics of the LED that is mounted directly 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 microchip is configured to independently control a current and/or voltage that is provided to the LED that is mounted directly thereon and electrically connected thereto so as to provide a uniform color point of the LED that is mounted directly thereon and electrically connected thereto notwithstanding the variations in electrical and/or optical characteristics of the LED that is mounted directly 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 microchip is electrically connected to a common data line and is addressed via the common data line.

9. An apparatus according to claim 8 wherein the LED device controller integrated circuit microchip is also electrically connected to a common power supply line.

10. 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.

11. A light emitting apparatus, comprising:

a plurality of Light Emitting Diode (LED) device controller integrated circuit microchips that include an LED device driver; and

a plurality of LEDs of same color but of different electrical and/or optical characteristics, a respective LED being electrically connected to and mounted directly on a respective LED device controller integrated circuit microchip, a respective LED device controller integrated circuit microchip 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.

12. An apparatus according to claim 11 wherein the respective LED device controller integrated circuit microchip 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.

13. An apparatus according to claim 11 wherein the respective LED device controller integrated circuit microchip 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.

14. An apparatus according to claim 11 wherein a respective LED device controller integrated circuit microchip includes a face having a reflective cavity therein and wherein a respective LED is mounted directly in the respective reflective cavity.

15. An apparatus according to claim 11 wherein 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 directly on a respective LED device controller integrated circuit microchip and electrically connected thereto.

16. An apparatus according to claim 11 further comprising a mounting substrate, wherein the a respective LED is mounted directly on a first face of a respective LED device controller integrated circuit microchip and wherein a second face of a respective LED device controller integrated circuit microchip that is opposite the first face is mounted on the mounting substrate and electrically connected thereto.

17. An apparatus according to claim 11 wherein the plurality of LED device controller integrated circuit microchips are electrically connected to a common data line and are individually addressed via the common data line.

18. An apparatus according to claim 17 wherein the plurality of LED device controller integrated circuit microchips are also electrically connected to a common power supply line.

19. An apparatus according to claim 11 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.

20. A light emitting apparatus, comprising:

a plurality of Light Emitting Diode (LED) device controller integrated circuit microchips that include an LED device driver; and

a plurality of LEDs of same color but of different electrical and/or optical characteristics, a respective LED being mounted directly on and electrically connected to a respective LED device controller integrated circuit microchip, a respective LED device controller integrated circuit microchip 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.

21. An apparatus according to claim 20 wherein the respective LED device controller integrated circuit microchip 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.

22. An apparatus according to claim 20 wherein the respective LED device controller integrated circuit microchip 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.

23. An apparatus according to claim 20 wherein a respective LED device controller integrated circuit microchip includes a face having a reflective cavity therein and wherein a respective LED is mounted directly in the respective reflective cavity.

24. An apparatus according to claim 20 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 microchip and electrically connected thereto.

25. An apparatus according to claim 20 further comprising a mounting substrate, wherein the a respective LED is mounted directly on a first face of a respective LED device controller integrated circuit microchip and wherein a second face of a respective LED device controller integrated circuit microchip that is opposite the first face is mounted on the mounting substrate and electrically connected thereto.

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

27. An apparatus according to claim 26 wherein the plurality of LED device controller integrated circuit microchips are also electrically connected to a common power supply line.

28. An apparatus according to claim 20 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.