System and method of updating drive scheme voltages

• US 8,780,104 B2
• Filed: 10/21/2011
• Issued: 07/15/2014
• Est. Priority Date: 03/15/2011
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Chuei, Nao S., Aflatooni, Koorosh, Van Lier, Wilhelmus Johannes Robertus, Varma, Pramod K., Goel, Ramesh K., Venugopal, Sameer
• Primary Examiner(s): PATEL, PREMAL R
• Application Number:
  US13/279,187
• Publication Number:
  US 20120235985A1
• Time in Patent Office: 998 Days
• Field of Search: 345/204, 345/209, 345/211, 345/214, 359/291
• US Class Current: 345/214
• CPC Class Codes: G09G 2320/0693 Calibration of display systems
• CPC Class Codes: G09G 3/3433 using light modulating elements actuated by an electric field and being other than liquid crystal devices and electrochromic devices using liquid crystal devices G09G3/36; using electrochromic devices G09G3/38
• CPC Class Codes: G09G 3/3466 based on interferometric effect
• CPC Class Codes: G09G 3/3629 using liquid crystals having memory effects, e.g. ferroelectric liquid crystals
• CPC Class Codes: G09G 3/3651 using multistable liquid crystals, e.g. ferroelectric liquid crystals

Abstract

This disclosure provides systems, methods and apparatus, including computer programs encoded on computer storage media, for calibrating display arrays. In one aspect, a method of calibrating a display array includes determining a particular drive response characteristic and updating a particular drive scheme voltage between updates of image data on the display array.

Claims

1. A method of calibrating drive scheme voltages in an array including a plurality of display elements, the method comprising:

determining, for a first subset of the display elements of the array, a first voltage characterizing a voltage which causes essentially all the display elements in the first subset to actuate from a released state;

determining, for a second subset of the display elements of the array, a second voltage characterizing a voltage which causes a first display element in the second subset to actuate from a released state but which does not cause a significant number of other display elements in the second subset to actuate from a released state;

determining, for a third subset of the display elements of the array, a third voltage characterizing a voltage which causes a first display element in the third subset to release from an actuated state but which does not cause a significant number of other display elements in the third subset to release from an actuated state; and

using the first, second, and third voltages to perform maintenance calibrations during use of the array over at least some portion of the life of the array.

2. The method of claim 1, further comprising determining at least one of the first, second, and third voltages for a fourth subset of display elements of the array, wherein the fourth subset is randomly or pseudorandomly selected.

3. The method of claim 2, further comprising substituting the fourth subset of display elements of the array for one of the first, second or third subsets of display elements of the array.

4. The method of claim 3, further comprising calibrating the drive scheme voltages using voltages determined for one or more of the first, second, or third subsets of display elements and the voltage determined for the fourth subset of display elements of the array.

5. The method of claim 1, further comprising determining at least one drive scheme voltage based at least in part on the first voltage, second voltage, and third voltage.

6. The method of claim 5, wherein the at least one drive scheme voltage includes one or both of a hold voltage and a segment voltage.

7. The method of claim 6, further comprising driving an array to display an image using the determined drive scheme voltages.

8. The method of claim 5, wherein using the first, second, and third voltages to perform maintenance calibrations includes repeatedly determining first, second, and third voltages, and updating drive scheme voltages based on the determined first, second, and third voltages at periodic intervals over the lifetime of the display.

9. The method of claim 1, wherein determining includes determining a hysteresis curve for a subset of display elements.

10. The method of claim 9, wherein determining includes computing a first derivative of a hysteresis curve for a subset of display elements.

11. A method of calibrating drive scheme voltages in an array including a plurality of display elements, the method comprising:

determining one or more drive response characteristics of one or more previously characterized subsets of display elements of the array;

deriving drive scheme voltages using the determined drive response characteristics determined for the one or more previously characterized subsets of display elements;

determining one or more drive response characteristics of an additional different subset of display elements of the array to characterize the additional different subset of display elements of the array; and

substituting the additional different subset of display elements of the array for one of the one or more previously characterized subsets of display elements of the array.

12. The method of claim 11, further comprising updating the drive scheme voltages using the drive response characteristics determined for one or more previously characterized subsets of display elements and the drive response characteristic of the additional different subset of display elements of the array.

13. The method of claim 12, wherein the drive response characteristics include one or more of a first voltage characterizing a voltage which causes essentially all the display elements in a first subset to actuate from a released state, a second voltage characterizing a voltage which causes a first display element in a second subset to actuate from a released state but which does not cause a significant number of other display elements in the subset to actuate from a released state, and a third voltage characterizing a voltage which causes a first display element in a third subset to release from an actuated state but which does not cause a significant number of other display elements in the subset to release from an actuated state.

14. The method of claim 13, wherein deriving includes substituting the determined drive response characteristics into formulas for drive scheme voltage values.

15. The method of claim 14, wherein at least some drive scheme voltage values are derived from the formulas:

VS=(VAMAX_—

H−

VRMAX_—

H+OV−

AL)/4

VH=VAMIN_—

H−

SO−

VS

wherein VS is a derived segment voltage, VH is a derived hold voltage, VAMAX_H is the first voltage characterizing a voltage which causes essentially all the display elements in the first subset to actuate from a released state, VRMAX_H is the second voltage characterizing a voltage which causes a first display element in a second subset to actuate from a released state but which does not cause a significant number of other display elements in the subset to actuate from a released state, VAMIN_H is the third voltage characterizing a voltage which causes a first display element in a third subset to release from an actuated state but which does not cause a significant number of other display elements in the subset to release from an actuated state, OV is an empirically determined value representing a voltage amount above VAMAX_H that is to be provided to the display elements during actuation, AL is an empirically determined value representing a voltage amount above VRMAX_H that is to be provided to the display elements during hold states; and

SO is an empirically determined value representing a voltage below above VAMIN_H that is to be provided to the display elements during hold states.

16. The method of claim 11, further comprising randomly or pseudorandomly selecting the additional different subset of display elements.

17. An apparatus for calibrating drive scheme voltages, the apparatus comprising:

an array of display elements;

display element state sensing circuitry; and

driver and processor circuitry configured to;

determine, for a first subset of the display elements of the array, a first voltage characterizing a voltage which causes essentially all the display elements in the first subset to actuate from a released state;

determine, for a second subset of the display elements of the array, a second voltage characterizing a voltage which causes a first display element in the second subset to actuate from a released state but which does not cause a significant number of other display elements in the second subset to actuate from a released state;

determine, for a third subset of the display elements of the array, a third voltage characterizing a voltage which causes a first display element in the third subset to release from an actuated state but which does not cause a significant number of other display elements in the third subset to release from an actuated state; and

use the first, second, and third voltages to perform maintenance calibrations during use of the array.

18. The apparatus of claim 17, wherein the driver and processor circuitry is further configured to determine at least one of the first, second, and third voltages for a fourth subset of display elements of the array, wherein the fourth subset is randomly or pseudorandomly selected.

19. The apparatus of claim 18, wherein the driver and processor circuitry is further configured to substitute the fourth subset of display elements of the array for one of the first, second or third subsets of display elements of the array.

20. The apparatus of claim 19, wherein the driver and processor circuitry is further configured to calibrate the drive scheme voltages using voltages determined for one or more of the first, second, or third subsets of display elements and the voltage determined for the fourth subset of display elements of the array.

21. The apparatus of claim 17, wherein the driver and processor circuitry is further configured to determine at least one drive scheme voltage based at least in part on the first voltage, second voltage, and third voltage.

22. The apparatus of claim 21, wherein the at least one drive scheme voltage includes one or both of a hold voltage and a segment voltage.

23. The apparatus of claim 22, wherein the driver and processor circuitry is further configured to drive an array to display an image using the determined drive scheme voltages.

24. The apparatus of claim 21, wherein the driver and processor circuitry is configured to use the first, second, and third voltages to perform maintenance calibrations by repeatedly determining first, second, and third voltages, and updating drive scheme voltages based on the determined first, second, and third voltages at periodic intervals over the lifetime of the display.

25. The apparatus of claim 17, further comprising:

a display;

a processor that is configured to communicate with the display, the processor being configured to process image data; and

a memory device that is configured to communicate with the processor.

26. The apparatus as recited in claim 25, further comprising:

a driver circuit configured to send at least one signal to the display; and

a controller configured to send at least a portion of the image data to the driver circuit.

27. The apparatus as recited in claim 25, further comprising:

an image source module configured to send the image data to the processor.

28. The apparatus as recited in claim 27, wherein the image source module includes at least one of a receiver, transceiver, and transmitter.

29. The apparatus as recited in claim 25, further comprising:

an input device configured to receive input data and to communicate the input data to the processor.

30. An apparatus for calibrating drive scheme voltages, the apparatus comprising:

an array of display elements;

display element state sensing circuitry; and

driver and processor circuitry capable of;

determining one or more drive response characteristics of one or more previously characterized subsets of display elements of the array;

deriving drive scheme voltages using the determined drive response characteristics determined for the one or more previously characterized subsets of display elements; and

determining one or more drive response characteristics of an additional different subset of display elements of the array to characterize the additional different subset of display elements of the array, and

substituting the additional different subset of display elements of the array for one of the one or more previously characterized subsets of display elements of the array.

31. The apparatus of claim 30, wherein the driver and processor circuitry is further capable of updating the drive scheme voltages using the drive response characteristics determined for one or more previously characterized subsets of display elements and the drive response characteristic of the additional different subset of display elements of the array.

32. The apparatus of claim 31, wherein the drive response characteristics include one or more of a first voltage characterizing a voltage which causes essentially all the display elements in a first subset to actuate from a released state, a second voltage characterizing a voltage which causes a first display element in a second subset to actuate from a released state but which does not cause a significant number of other display elements in the subset to actuate from a released state, and a third voltage characterizing a voltage which causes a first display element in a third subset to release from an actuated state but which does not cause a significant number of other display elements in the subset to release from an actuated state.

33. The apparatus of claim 32, wherein deriving comprises substituting the determined drive response characteristics into formulas for drive scheme voltage values.

34. The apparatus of claim 33, wherein at least some drive scheme voltage values are derived from the formulas:

VS=(VAMAX_—

H−

VRMAX_—

H+OV−

AL)/4

VH=VAMIN_—

H−

SO−

VS

wherein VS is a derived segment voltage, VH is a derived hold voltage, VAMAX_H is the first voltage characterizing a voltage which causes essentially all the display elements in the first subset to actuate from a released state, VRMAX_H is the second voltage characterizing a voltage which causes a first display element in a second subset to actuate from a released state but which does not cause a significant number of other display elements in the subset to actuate from a released state, VAMIN_H is the third voltage characterizing a voltage which causes a first display element in a third subset to release from an actuated state but which does not cause a significant number of other display elements in the subset to release from an actuated state, OV is an empirically determined value representing a voltage amount above VAMAX_H that is to be provided to the display elements during actuation, AL is an empirically determined value representing a voltage amount above VRMAX_H that is to be provided to the display elements during hold states; and

SO is an empirically determined value representing a voltage below above VAMIN_H that is to be provided to the display elements during hold states.

35. The apparatus of claim 30, wherein the driver and processor circuitry is further-capable of selecting randomly or pseudorandomly the additional different subset of display elements.

36. A non-transitory tangible computer readable media having stored thereon instructions causing a driver circuit to perform a method of:

determining, for a first subset of the display elements of the array, a first voltage characterizing a voltage which causes essentially all the display elements in the first subset to actuate from a released state;

determining, for a second subset of the display elements of the array, a second voltage characterizing a voltage which causes a first display element in the second subset to actuate from a released state but which does not cause a significant number of other display elements in the second subset to actuate from a released state;

determining, for a third subset of the display elements of the array, a third voltage characterizing a voltage which causes a first display element in the third subset to release from an actuated state but which does not cause a significant number of other display elements in the third subset to release from an actuated state; and

using the first, second, and third voltages to perform maintenance calibrations during use of the array.

37. The computer readable media of claim 36, wherein the instructions cause the driver circuit to determine at least one drive scheme voltage based at least in part on the first voltage, second voltage, and third voltage.

38. The computer readable media of claim 37, wherein the at least one drive scheme voltage is one or both of a hold voltage and a segment voltage.

39. The computer readable media of claim 38, wherein the instructions cause the driver circuit to drive an array to display an image using the determined drive scheme voltages.

40. The computer readable media of claim 38, wherein the instructions cause the driver circuit to use the first, second, and third voltages to perform maintenance calibrations by repeatedly determining first, second, and third voltages, and updating drive scheme voltages based on the determined first, second, and third voltages at periodic intervals over the lifetime of the display.

41. A non-transitory tangible computer readable media having stored thereon instructions causing a driver circuit to perform a method of:

determining one or more drive response characteristics of one or more previously characterized subsets of display elements of the array;

deriving drive scheme voltages using the determined drive response characteristics determined for the one or more previously characterized subsets of display elements;

determining one or more drive response characteristics of an additional different subset of display elements of the array to characterize the additional different subset of display elements of the array, and

substituting the additional different subset of display elements of the array for one of the one or more previously characterized subsets of display elements of the array.

42. The computer readable media of claim 41, wherein the instructions cause the driver circuit to update the drive scheme voltages using the drive response characteristics determined for one or more previously characterized subsets of display elements and the drive response characteristic of the additional different subset of display elements of the array.