Color control for scanning backlight

• US 7,759,882 B2
• Filed: 07/16/2007
• Issued: 07/20/2010
• Est. Priority Date: 07/31/2006
• Status: Expired due to Fees

• Current Assignee: Polaris PowerLED Technologies, LLC (Microchip Technology Incorporated)
• Original Assignee: Microsemi Corp. - Analog Mixed Signal Group, Ltd. (Microchip Technology Incorporated)
• Inventors: Ferentz, Alon, Korcharz, Dror, Peker, Arkadiy
• Primary Examiner(s): Owens; Douglas W
• Assistant Examiner(s): A; Minh D
• Application Number:
  US11/778,093
• Publication Number:
  US 20080024076A1
• Time in Patent Office: 1,100 Days
• Field of Search: 315/291, 315/307, 315/185.R, 315/312, 315/313, 315/315, 345204-205, 345/207, 345/690, 345/696, 345698-699, 345 45- 46, 345/48, 362/800
• US Class Current: 315/312
• 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 for use with a display exhibiting a plurality of lighting regions, the system comprising:

a color manager;

a plurality of luminaires each exhibiting an optical output, each of said luminaires comprising a plurality of colored LED strings and arranged to illuminate a unique one of the plurality of lighting regions of the display with the optical output of the respective luminaire, the optical output of each of the respective luminaires restricted to the respective unique lighting region;

a color sensor arranged to receive light from one of the plurality of lighting regions; 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 and spatially separated from all other of said plurality of thermal sensors, said plurality of thermal sensors being fewer in number than said plurality of luminaires;

said color manager, responsive to said plurality of thermal sensors and said color sensor, operative to calculate an estimated thermal temperature for at least one of said plurality of luminaires and control a drive signal of each of said plurality of luminaires so as to maintain a uniform color, said controlled drive signal being responsive to said calculated estimated thermal temperature.

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

3. A backlighting system according to claim 2, wherein said color sensor receives light from said lighting region illuminated by said particular luminaire having associated therewith said at least one thermal sensor.

4. A backlighting system according to claim 1, further comprising a plurality of optical partitions, each of said optical partitions arranged between two of said plurality of luminaires so as to reduce optical interaction between a first of said two luminaires and the unique display portion illuminated by a second of said two luminaires, thereby restricting the optical output of each of said luminaires to the respective unique lighting region.

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

6. A backlighting system according to claim 5, 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.

7. A backlighting system according to claim 5, 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.

8. 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.

9. A backlighting system according claim 8, wherein said particular location of a second one of said plurality of thermal sensors is associated with a bottom of said chassis.

10. 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.

11. A backlighting system according to claim 1, wherein each of the lighting regions of the display is arranged horizontally, the horizontally arranged lighting regions being stacked vertically.

12. 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.

13. A method of backlighting comprising:

providing a plurality of luminaires, each of said provided luminaires comprising a plurality of colored LED strings and exhibiting an optical output;

arranging each of said provided luminaires to illuminate, with the respective optical output, a unique one of a plurality of lighting regions of a display associated therewith;

restricting the optical output of each of said provided luminaires to the respective unique lighting region;

sensing the illumination color of one of the lighting regions;

sensing a plurality of thermal temperatures each associated with a particular one of a plurality of pre-determined locations in relation to said provided plurality of luminaires, each of said plurality of pre-determined locations being spatially separated from all other of said plurality of pre-determined locations, said plurality of locations being less in number than said plurality of luminaires;

calculating an estimated thermal temperature for at least one of said provided plurality of luminaires responsive to said sensed plurality of thermal temperatures; and

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

14. A method of backlighting according to claim 13, wherein one of said plurality of pre-determined locations is coincident with one of said provided plurality of luminaires.

15. A method of backlighting according to claim 14, wherein said one of said provided plurality of luminaires coincident with said one of said plurality of pre-determined locations is said luminaire illuminating said lighting region having said sensed illumination color.

16. A method of backlighting according to claim 13, wherein said restricting the optical output comprises:

optically partitioning said provided plurality of luminaires so as to reduce optical interaction between a first of said provided plurality of luminaires and the lighting region illuminated by a second one of said provided plurality of luminaires.

17. A method of backlighting according to claim 13, further comprising:

arranging each of said provided plurality of luminaires horizontally; and

stacking said provided plurality of luminaires vertically.

18. A method of backlighting according to claim 17, wherein a first one of said plurality of pre-determined locations is coincident with a top one of said stacked horizontally arranged luminaires.

19. A method of backlighting according to claim 18, wherein a second one of said plurality of pre-determined locations is coincident with a bottom one of said stacked horizontally arranged luminaires.

20. A method of backlighting according to claim 13, further comprising:

providing a chassis; and

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

21. A method of backlighting according to claim 20, wherein a second one of said plurality of pre-determined locations is associated with the bottom of said provided chassis.

22. A method of backlighting according to claim 13, further comprising:

providing a chassis; and

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

23. A method of backlighting according to claim 13, further comprising:

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

24. A method of backlighting according to claim 13, 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.

25. A backlighting system for use with a display exhibiting a plurality of lighting regions, the system comprising:

a color manager;

a plurality of luminaires each exhibiting an optical output, each of said luminaires comprising a LED string arranged to illuminate a unique one of the plurality of lighting regions of the display with the respective optical output thereof, each of said luminaires optically isolated from all lighting regions of the display other than the respective unique one;

a color sensor arrange to receive light from only 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 in number than said plurality of luminaires, each of said plurality of thermal sensors spatially separated from all other of said plurality of thermal sensors,

said color manager, responsive to said plurality of thermal sensors and said color sensor, operative to;

calculate, responsive to said plurality of thermal sensors, an estimated thermal temperature for at least one of said plurality of luminaires for which a thermal sensor is not associated; and

calculate, responsive to said color sensor and said calculated estimated thermal temperature, color coordinates for each of said plurality of luminaires.

26. A method of backlighting for use with a display having a plurality of lighting regions, the method comprising:

providing a plurality of luminaires each exhibiting an optical output;

arranging each of said provided plurality of luminaires to illuminate a unique one of the plurality of lighting regions of the display with the respective optical output thereof;

optically isolating each of said provided luminaires from all lighting regions of the display other than said respective unique lighting region;

sensing the illumination color of only one of said provided luminaires;

sensing a thermal temperature associated with a plurality of pre-determined locations in relation to said provided plurality of luminaires, the number of said plurality of locations being less than the number of said plurality of luminaires, each of said plurality of pre-determined locations being spatially separated from all other of said plurality of pre-determined locations, at least one of said temperature sensed pre-determined locations being associated with said illumination color sensed provided luminaire;

calculating an estimated thermal temperature for at least one of said provided plurality of luminaires responsive to said sensed thermal temperature of said plurality of pre-determined locations; and

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