Systems and methods for controlling a solid state lighting panel

• US 8,049,709 B2
• Filed: 05/08/2007
• Issued: 11/01/2011
• Est. Priority Date: 05/08/2007
• Status: Active Grant

• Current Assignee: Brightplus Ventures LLC (IPValuation Partners, LLC)
• Original Assignee: CREE Incorporated (Wolfspeed, Inc.)
• Inventors: Vadas, Keith J., Roberts, John K.
• Primary Examiner(s): Patel; Nitin
• Application Number:
  US11/745,713
• Publication Number:
  US 20080278097A1
• Time in Patent Office: 1,638 Days
• Field of Search: 345/72, 345/88, 345/102, 345/204
• US Class Current: 345/102
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2310/08 Details of timing specific for flat panels, other than clock recovery
• CPC Class Codes: G09G 2320/064 by time modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2330/06 Handling electromagnetic interferences [EMI], covering emitted as well as received electromagnetic radiation
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: G09G 3/342 using several illumination sources separately controlled corresponding to different display panel areas, e.g. along one dimension such as lines
• CPC Class Codes: H05B 45/22 using optical feedback
• CPC Class Codes: H05B 45/397 Current mirror circuits
• CPC Class Codes: H05B 47/155 Coordinated control of two or more light sources
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

Provided are systems and methods for controlling a solid state lighting panel. A system according to some embodiments of the invention includes a controller that provides control signals to current drivers that are configured to provide current to multiple solid state lighting devices. The system also includes a sequence generator that generates a firing sequence for firing multiple strings of slid state lighting devices.

Claims

1. A lighting panel system, comprising:

a lighting panel including a plurality of strings of solid state lighting devices arranged across the panel in a first direction and positioned at intervals in a second direction that is substantially orthogonal to the first direction;

a current supply circuit configured to selectively supply a plurality of on-state drive currents to the plurality of strings responsive to a plurality of control signals; and

a control system configured to selectively provide control signals to the current supply circuit to selectively drive the plurality of strings, the control system further including firing logic configured to determine a firing order of the plurality of strings.

2. The system of claim 1, wherein the firing logic comprises rule-based logic operative to generate a non-spatially-sequential firing order.

3. The system of claim 2, wherein the rule-based logic comprises a rule that a second string fired after a first string is non-adjacent the first string.

4. The system of claim 2, wherein the rule-based logic comprises a rule that a first string is fired simultaneously with a second string, wherein the first string is non-adjacent the second string.

5. The system of claim 1, wherein the lighting panel further comprises a plurality of bars that include portions of the plurality of strings, wherein the plurality of bars extend across the panel in the first direction and are positioned adjacent one another in a substantially parallel arrangement.

6. The system of claim 5, wherein the firing order is operative to cause a first firing, a second firing and a third firing, wherein the first firing occurs before the second firing and the second firing occurs before the third firing, wherein the first firing supplies current for at least one string in a first bar, the second firing supplies current for at least one string in a second bar and the third firing supplies current for at least one string in a third bar, wherein the second bar is located below the first bar and the third bar is located above the second bar.

7. The system of claim 5, further comprising:

a first portion of the plurality of strings including solid state lighting devices that emit light in a first dominant wavelength; and

a second portion of the plurality of strings including solid state lighting devices that emit light in a second dominant wavelength,

wherein each of the plurality of bars includes at least one string of the first portion of the plurality of strings and at least one string of the second portion of the plurality of strings and wherein each of the first portion of the plurality of strings is fired in the firing order and then each of the second portion of the plurality of strings is fired in the firing order.

8. The system of claim 5, further comprising:

a first portion of the plurality of strings including solid state lighting devices that emit light in a first dominant wavelength; and

a second portion of the plurality of strings including solid state lighting devices that emit light in a second dominant wavelength,

wherein at least one string of the first portion of the plurality of strings is fired simultaneously with at least one string of the second portion of the plurality of strings.

9. The system of claim 5, further comprising:

a first portion of the plurality of strings in a first bar; and

a second portion of the plurality of strings in a second bar,

wherein the first and second portions of the plurality of strings are fired sequentially in the firing order and wherein the firing order is configured to determine the location of the second bar relative to the location of the first bar.

10. The system of claim 1, further comprising:

a first portion of the plurality of strings including solid state lighting devices that emit light in a first dominant wavelength; and

a second portion of the plurality of strings including solid state lighting devices that emit light in a second dominant wavelength,

wherein each of the first portion of the plurality of strings is fired in the firing order and then each of the second portion of the plurality of strings is fired in the firing order.

11. The system of claim 1, wherein the firing logic comprises random logic operative to generate the firing order.

12. The system of claim 1, further comprising a means for generating a feedback signal configured to provide display performance information to the control system.

13. The system of claim 1,

wherein the current supply circuit comprises a plurality of phase drivers configured to supply a plurality of on-state drive currents at a plurality of times in a firing cycle,

wherein the plurality of strings of solid state lighting devices comprise a plurality of string groups, each configured to receive current from one of the plurality of phase drivers, and

wherein the control system is further configured to determine the plurality of times that each of the plurality of phase drivers begin to supply current to the plurality of string groups.

14. The system of claim 13, wherein the ratio of a quantity of the plurality of phase drivers to a quantity of the plurality of strings of solid state lighting devices is one and wherein each of the plurality of string groups comprises one of the plurality of strings of solid state lighting devices.

15. The system of claim 1, wherein the control system is configured to receive a synchronizing signal from a display controller configured to control a display and wherein the firing order is synchronized with periodic operations of the display.

16. A method for controlling a solid state lighting panel including a plurality of strings of solid state lighting devices configured to extend from a first edge of the panel to a second edge of the panel in substantially adjacent positions relative to one another, the method comprising supplying a plurality of pulsed drive currents to the plurality of strings in a non-spatially-sequential firing order.

17. The method of claim 16, further comprising:

determining the firing order that supplies current to a first string of the plurality of strings and a second string of the plurality of strings; and

defining the second string of the plurality of strings, wherein the defining is based on a location of the first string.

18. The method of claim 17, wherein defining the second string comprises selecting one of the plurality of strings that is not adjacent to the first string.

19. The method of claim 17, wherein defining the second string comprises selecting one of the plurality of strings that is located a minimum quantity of strings from the first string.

20. The method of claim 17, further comprising defining a third string of the plurality of strings, wherein the third string is configured to be fired after the second string and wherein the defining is based on a location of the second string and the location of the first string.

21. The method of claim 20, wherein defining the second string comprises selecting one of a plurality of strings that is on a first side of the first string and defining the third string comprises selecting one of the plurality of strings that is on a second side of the second string.

22. The method of claim 16, further comprising grouping a plurality of portions of the plurality of strings on a plurality of bars, wherein the plurality of bars extend across the panel from the first edge to the second edge and are positioned adjacent one another in a substantially parallel arrangement.

23. The method of claim 22, further comprising simultaneously supplying current to the portion of the plurality of strings that are in the same one of the plurality of bars.

24. The method of claim 22, further comprising simultaneously supplying current to a first string located in a first bar and a second string located in a second bar.

25. The method of claim 22, further comprising:

generating a random number;

assigning a value to each of the plurality of bars; and

simultaneously supplying current to the portion of the plurality of strings on one of the plurality of bars based on the random number.

26. The method of claim 16, further comprising:

supplying current to a first portion of the plurality of strings according to the firing order, wherein the first portion of the plurality of strings includes solid state lighting devices configured to emit light in a first dominant wavelength; and

supplying current to a second portion of the plurality of strings according to the firing order after supplying current to the first portion of the plurality of strings, wherein the second portion of the plurality of strings includes solid state lighting devices configured to emit light in a second dominant wavelength.

27. The method of claim 16, wherein defining is further based on a dominant wavelength of light emitted by the solid state lighting devices in the first string.

28. The method of claim 16, further comprising simultaneously supplying current to a first string including solid state lighting devices configured to emit light in a first dominant wavelength and a second string including solid state lighting devices configured to emit light in a second dominant wavelength.

29. The method of claim 16, further comprising:

determining the firing order that supplies current to a first string of the plurality of strings and a second string of the plurality of strings; and

defining the second string based on a dominant wavelength emitted by the solid state lighting devices in the first string and a relative position of the first string.

30. The method of claim 16, comprising determining the firing order using a numerical technique.

31. The method of claim 30, further comprising:

generating a random number;

assigning a value to each of the plurality of strings; and

supplying current to one of the plurality of strings based on the random number.

32. The method of claim 30, wherein the numerical technique comprises performing a non-linear calculation.

33. The method of claim 16, wherein the firing order comprises a deterministic order based on at least one rule.

34. A system for controlling a solid state lighting panel including a plurality of strings of solid state lighting devices that are arranged to extend across the panel in a first direction and are positioned adjacent one another in a second direction and that are supplied current by a plurality of current drivers, the system comprising:

a sequence generator that generates a firing sequence for firing the plurality of strings; and

a controller that provides control signals, responsive to the sequence generator, to the plurality of current drivers.

35. The system of claim 34, wherein the sequence generator comprises a deterministic algorithm that determines a location of a subsequently fired string based on a location of at least one previously fired string.

36. The system of claim 34, wherein the sequence generator comprises an algorithm that generates a sequence to fire a first string having a plurality of solid state lighting devices that emit light in a first dominant wavelength and a second string having a plurality of solid state lighting devices that emit light in a second dominant wavelength, wherein the second string is fired after the first string.

37. The system of claim 34, wherein the sequence generator comprises an algorithm that generates a sequence to simultaneously fire a first string having a plurality of solid state lighting devices that emit light in a first dominant wavelength and a second string having a plurality of solid state lighting devices that emit light in a second dominant wavelength.

38. The system of claim 34, wherein the sequence generator generates a random sequence of firing.

39. The system of claim 34, further comprising a plurality of bars that include portions of the plurality of strings, wherein the plurality of bars extend across the panel in the first direction and are positioned adjacent one another in the second direction.

40. The system of claim 39, wherein the firing sequence is configured to simultaneously fire a first portion of the plurality of strings and then simultaneously fire a second portion of the plurality of strings and wherein the first portion is located on a first bar and the second portion is located on a second bar.

41. The system of claim 39, wherein the firing sequence is configured to simultaneously fire a first string on a first bar and a second string on a second bar.

42. The system of claim 41, wherein the first string includes solid state lighting devices that emit light in a first dominant wavelength and the second string includes solid state lighting devices that emit light in a second dominant wavelength.

43. The system of claim 34, further comprising:

a first portion of the plurality of strings including solid state lighting devices that emit light in a first dominant wavelength; and

a second portion of the plurality of strings including solid state lighting devices that emit light in a second dominant wavelength;

wherein each of the plurality of bars includes at least one string of the first portion of the plurality of strings and at least one string of the second portion of the plurality of strings.

44. The system of claim 43, wherein the firing sequence is operative to cause the first portion of strings to fire in a first sequence and to then to cause the second portion of strings to fire in the first sequence.

45. The system of claim 34, wherein the plurality of drivers comprise a polyphase power supply configured to a supply a plurality of temporally shifted drive currents to a plurality of groups of the plurality of strings.

46. A method for controlling a solid state lighting panel including a plurality of strings of solid state lighting devices configured to extend from a first edge of the panel to a second edge of the panel in substantially adjacent positions relative to one another, the method comprising supplying a plurality of pulsed drive currents to a plurality of groups of the plurality of strings.

47. The method of claim 46, wherein each group of the plurality of groups comprises one of the plurality of strings and wherein one of the plurality of pulsed drive currents is provided for each of the plurality of strings by one of a plurality of phase drivers.

48. The method of claim 47, further comprising receiving a synchronizing signal from a display controller configured to control a refresh rate of display pixels.

49. The method of claim 46, further comprising synchronizing the plurality of drive currents with a cycles of a periodic operation of a display panel.

50. The method of claim 49, wherein the periodic operation comprises refreshing pixels and wherein the display panel comprises an LCD display panel.

51. A lighting panel system, comprising:

a lighting panel including a plurality of strings of solid state lighting devices arranged across the panel in a first direction and positioned at intervals in a second direction that is substantially orthogonal to the first direction;

a current supply circuit configured to selectively supply a plurality of on-state drive currents to the plurality of strings responsive to a plurality of control signals;

a control system configured to selectively provide control signals to the current supply circuit to selectively drive the plurality of strings, the control system further including firing logic configured to determine a firing order of the plurality of strings; and

wherein the firing logic is configured to drive the plurality of strings in a spatially non-adjacent, non-sequential firing order and/or to drive the plurality of strings at different times for at least a subset of the plurality of strings.

52. The system of claim 51, wherein the firing logic is further configured to drive the plurality of strings and/or portions thereof at least partially based on the spatial relationship between the plurality of strings and or portions thereof.

53. The system of claim 51, wherein the firing logic comprises rule-based logic configured to generate a non-spatially sequential firing order.

54. The system of claim 53, wherein the rule-based logic further comprises a rule that a second string fired after a first string is non-adjacent the first string.

55. The system of claim 53, wherein the rule-based logic further comprises a rule that if first string is fired simultaneously with a second string, then the first string is non-adjacent the second string.