Color Control for Scanning Backlight

• US 20080024076A1
• Filed: 07/16/2007
• Published: 01/31/2008
• Est. Priority Date: 07/31/2006
• Status: Active Grant

• Current Assignee: Polaris PowerLED Technologies, LLC (Microchip Technology Incorporated)
• Original Assignee: Powerdsine Limited - Microsemi Corporation
• Inventors: PEKER, Arkadiy, KORCHARZ, Dror, FERENTZ, Alon
• Granted Patent: US 7,759,882 B2
• Time in Patent Office: Days
• US Class Current: 315/308
• CPC Class Codes: H05B 45/22 using optical feedback
• CPC Class Codes: H05B 45/28 using temperature feedback
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

A backlighting system comprising: a color manager; a plurality of luminaires, each of the luminaires comprising a LED string and arranged to illuminate a particular portion of a display associated therewith; a color sensor arrange to receive light from one of the luminaires; and a plurality of thermal sensors each associated with a particular luminaire and in communication with the color manager, the plurality of thermal sensors being less than the plurality of luminaires, the color manager, responsive to the plurality of thermal sensors and the color sensor, being operable to calculate color coordinates for each of the plurality of luminaires.

Claims

1. A backlighting system comprising:

a color manager;

a plurality of luminaires, each of said luminaires comprising a plurality of colored LED strings and arranged to illuminate a particular portion of a display associated therewith;

a color sensor arranged to receive light from one of the plurality of luminaires; and

a plurality of thermal sensors in communication with said color manager, each of said thermal sensors secured at a particular location relative to said plurality of luminaires, said plurality of thermal sensors being fewer than said plurality of luminaires;

said color manager, responsive to said plurality of thermal sensors and said color sensor, being operable to control a drive signal of each of said plurality of luminaires so as to maintain a uniform color.

2. A backlighting system according to claim 1, wherein said color manager is further operable to calculate a temperature for at least one of said plurality of luminaires, said controlled drive signal being responsive to said estimated temperature.

3. A backlighting system according to claim 1, wherein at least one of said plurality of thermal sensors is associated with a particular luminaires

4. A backlighting system according to claim 3, wherein said color sensor receives light from said particular luminaire having associated therewith said at least one thermal sensor.

5. A backlighting system according to claim 1, further comprising a plurality of optical partitions each arranged between two of said plurality of luminaires so as to reduce optical interaction between a first of said two luminaires and the display portion associated with a second of said two luminaires.

6. A backlighting system according to claim 1, wherein each of said plurality of luminaires is arranged horizontally, said plurality of luminaires being stacked vertically.

7. A backlighting system according to claim 6, wherein said particular location of one of said plurality of thermal sensors is associated with a top one of said horizontally arranged stacked plurality of luminaires.

8. A backlighting system according to claim 6, wherein said particular location of one of said plurality of thermal sensors is associated with a bottom one of said horizontally arranged stacked plurality of luminaires.

9. A backlighting system according to claim 1, further comprising a chassis arranged to secure said plurality of luminaires, wherein said particular location of a first one of said plurality of thermal sensors is associated with a top of said chassis.

10. A backlighting system according claim 9, wherein said particular location of a second one of said plurality of thermal sensors is associated with a bottom of said chassis.

11. A backlighting system according to claim 1, further comprising a chassis arranged to secure said plurality of luminaires, wherein one of said plurality of thermal sensors is associated with a bottom of said chassis.

12. A backlighting system according to claim 1, wherein each of the particular portions of the display associated with said luminaires are arranged horizontally, the particular portions being stacked vertically.

13. A backlighting system according to claim 1, wherein said control of the output is associated with a pulse width modulation in sequence with a scanning period of the display.

14. A method of backlighting comprising:

providing a plurality of luminaires, each of said luminaires comprising a plurality of colored LED strings and arranged to illuminate a particular portion of a display associated therewith;

sensing the illumination color of one of said provided luminaires;

sensing a temperature associated with a plurality of pre-determined locations in relation to said provided plurality of luminaires, said plurality of locations being less than said plurality of luminaires; and

controlling the color of each of said provided plurality of luminaires responsive to said sensed illumination color and said sensed temperature.

15. A method of backlighting according to claim 14, further comprising:

calculating an estimated temperature for at least one of said plurality of luminaires,

said controlling the color being responsive to said calculated estimated temperature.

16. A method of backlighting according to claim 14, wherein one of said plurality of locations is coincident with one of said provided plurality of luminaires.

17. A method of backlighting according to claim 16, wherein said one of said provided plurality of luminaires coincident with said one of said plurality of locations is said one of said provided plurality of luminaires having said sensed illumination color.

18. A method of backlighting according to claim 14, further comprising:

optically partitioning said provided plurality of luminaires so as to reduce optical interaction between a first of said provided plurality of luminaires and the display portion associated with a second one of said provided plurality of luminaires.

19. A method of backlighting according to claim 14, further comprising:

arranging each of said provided plurality of luminaires horizontally; and

stacking said provided plurality of luminaires vertically.

20. A method of backlighting according to claim 19, wherein a first one of said plurality of locations is coincident with a top one of said stacked horizontally arranged luminaires.

21. A method of backlighting according to claim 20, wherein a second one of said plurality of locations is coincident with a bottom one of said stacked horizontally arranged luminaires.

22. A method of backlighting according to claim 14, further comprising:

providing a chassis; and

securing said provided plurality of luminaires to said provided chassis, wherein a first one of said plurality of locations is associated with the top of said provided chassis.

23. A method of backlighting according to claim 22, wherein a second one of said plurality of locations is associated with the bottom of said provided chassis.

24. A method of backlighting according to claim 14, further comprising:

providing a chassis; and

securing said provided plurality of luminaires to said provided chassis, wherein one of said plurality of locations is associated with the bottom of said provided chassis.

25. A method of backlighting according to claim 14, further comprising:

inputting the thermodynamic relationship between said plurality of locations and each of said provided plurality of luminaires, said controlling the color being responsive to said input thermodynamic relationship.

26. A method of backlighting according to claim 14, wherein said controlling the color comprises pulse width modulating each of the provided plurality of luminaires in sequence with a scanning period of the display.

27. A backlighting system comprising:

a color manager;

a plurality of luminaires, each of said luminaires comprising a LED string and arranged to illuminate a particular portion of a display associated therewith;

a color sensor arrange to receive light from one of the luminaires; and

a plurality of thermal sensors each associated with a particular luminaire and in communication with said color manager, said plurality of thermal sensors being less than said plurality of luminaires,

said color manager, responsive to said plurality of thermal sensors and said color sensor, being operable to calculate color coordinates for each of said plurality of luminaires.

28. A method of backlighting comprising:

providing a plurality of luminaires, each of said luminaires comprising a plurality of colored LED strings and arranged to illuminate a particular portion of a display associated therewith;

sensing the illumination color of one of said provided luminaires;

sensing a temperature associated with a plurality of pre-determined locations in relation to said provided plurality of luminaires, said plurality of locations being less than said plurality of luminaires, at least one of said temperature sensed pre-determined locations being associated with said illumination color sensed provided luminaire; and

controlling the color of each of said provided plurality of luminaires responsive to said sensed illumination color and said sensed temperature.