Sensing to determine pixel state in a passively addressed display array

• US 8,466,858 B2
• Filed: 02/03/2009
• Issued: 06/18/2013
• Est. Priority Date: 02/11/2008
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Govil, Alok
• Primary Examiner(s): Sniezek, Andrew L
• Application Number:
  US12/365,089
• Publication Number:
  US 20090201242A1
• Time in Patent Office: 1,596 Days
• Field of Search: None
• US Class Current: 345/85
• CPC Class Codes: G02F 1/133514 Colour filters
• CPC Class Codes: G09G 2320/0693 Calibration of display systems
• CPC Class Codes: G09G 2320/08 Arrangements within a display terminal for setting, manually or automatically, display parameters of the display terminal
• CPC Class Codes: G09G 3/006 Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays testing individual LED's G01R31/2635; testing lamps G01R31/44; testing of optical features of LCD displays G02F1/1309
• CPC Class Codes: G09G 3/346 based on modulation of the reflection angle, e.g. micromirrors micromirrors devices per se G02B26/0833
• CPC Class Codes: G09G 3/3466 based on interferometric effect

Abstract

Devices and methods for determining an operational state of a selected display device in an array of display devices. One method includes determining the operational state of a particular display device in the array by measuring an electrical characteristic of a plurality of the display devices, and determining the operational state based at least in part on the three measurements. In some embodiments, the electrical characteristic is capacitance, in other embodiments impedance can be the measured electrical characteristic. Such methods can be applied to interferometric modulator displays and other displays, including liquid crystal display displays.

Claims

1. In an array of electrical devices formed in rows and columns, the array coupled to a plurality of row electrodes and a plurality of column electrodes, a method of determining an electrical characteristic of one or more selected electrical devices, each selected electrical device located in a selected row of the array and in a selected column of the array, the method comprising:

determining a first value of the electrical characteristic between selected one or more row electrodes and said plurality of column electrodes, said plurality of column electrodes being driven to a common voltage and at least a portion of non-selected row electrodes being configured in a floating state for the first value;

determining a second value of the electrical characteristic between the selected one or more column electrodes and said plurality of row electrodes, said plurality of row electrodes being driven to a common voltage and at least a portion of non-selected column electrodes being configured in a floating state for the second value;

determining a third value of an electrical characteristic between the selected one or more row electrodes and the selected one or more column electrodes, the non-selected column and row electrodes being configured in a floating state for the determination of the third value; and

determining a resulting electrical characteristic or operational state of the one or more selected electrical devices based at least in part on the first and second values, and the third value of the electrical characteristic.

2. The method of claim 1, wherein the array of electrical devices comprises microelectromechanical electrical devices.

3. The method of claim 2, wherein the microelectromechanical devices comprise at least one interferometric modulator.

4. The method of claim 1, wherein the array of electrical devices comprises liquid crystal display (LCD) devices.

5. The method of claim 1, wherein each of the selected one or more electrical devices are each coupled to a selected row electrode and a selected column electrode where they intersect.

6. The method of claim 1, wherein said plurality of row electrodes are driven to a common voltage by commonly connecting the plurality of row electrodes.

7. The method of claim 1, wherein said plurality of column electrodes are driven to a common voltage by commonly connecting the plurality of column electrodes.

8. The method of claim 1, wherein the electrical characteristic comprises capacitance.

9. The method of claim 8, wherein determining capacitance (C_selected—

<sub>display—

device</sub>) of the one or more selected electrical devices comprises using the first value (C<sub>first—

value</sub>), the second value (C<sub>second—

value</sub>), and the third value (C<sub>third—

value</sub>) in substantially the following relationship;

10. The method of claim 1, wherein the electrical characteristic comprises impedance.

11. The method of claim 1, wherein determining an operational state of the one or more selected electrical device comprises comparing the electrical characteristic of said one or more selected electrical devices and a threshold value.

12. A method of determining an operational state of a selected electrical device in a selected row and a selected column of an array, the array comprising a plurality of electrical devices each coupled to a row electrode and a column electrode of a plurality of row electrodes and a plurality of column electrodes of the display, the method comprising:

determining capacitance between the selected row electrode and a plurality of commonly connected column electrodes;

determining capacitance between the selected column electrode and a plurality of commonly connected row electrodes;

determining capacitance between the selected row electrode and the selected column electrode; and

determining a state of the selected electrical device based at least in part on the determined capacitances.

13. The method of claim 12, wherein the array of electrical devices comprises interferometric modulators.

14. A method of estimating capacitance of one or more selected electrical devices in an array having a plurality of rows of electrical devices and a plurality of columns of electrical devices, the method comprising:

determining capacitance C_row between row electrodes coupled to the selected electrical devices and a plurality of column electrodes coupled to the plurality of columns, the plurality of column electrodes driven to a common voltage;

determining capacitance C_column between column electrodes coupled to the selected electrical devices and a plurality of row electrodes coupled plurality of rows, the plurality of row electrodes driven to a common voltage;

determining capacitance C_effective between the row electrodes and the column electrode coupled to the selected electrical devices; and

estimating capacitance C_P of the selected electrical devices based at least in part on the determined capacitances C_row, C_column, and C_effective.

15. The method of claim 14, wherein estimating capacitance C_P comprises using the capacitance C_row, the capacitance C_column, and the capacitance C_effective in substantially the following relationship:

16. The method of claim 14, wherein the plurality of row electrodes are driven to a common voltage by commonly connecting the plurality of row electrodes.

17. The method of claim 14, wherein the plurality of column electrodes are driven to a common voltage by commonly connecting the plurality of column electrodes.

18. The method of claim 14, further comprising estimating the operational state of the selected electrical devices by comparing the capacitance of the selected electrical devices and a threshold value.

19. A device for estimating capacitance of one or more selected electrical devices in an array of electrical devices, comprising:

at least one driving circuit;

an array of electrical devices, each electrical device being coupled to one of a plurality of first electrodes and one of a plurality of second electrodes;

measurement circuitry configured to

determine capacitance C_row between first electrodes coupled to the selected electrical devices and a plurality of second electrodes coupled to the array, the second electrodes driven to a common voltage potential,

determine capacitance C_column between second electrodes coupled to the selected electrical devices and a plurality of first electrodes coupled to the array, the first electrodes driven to a common voltage potential, and

determine capacitance C_effective between the first electrodes and the second electrodes coupled to the selected electrical devices; and

capacitance estimating circuitry configured to estimate capacitance C_p of the selected electrical device based at least in part on the determined capacitances.

20. The device of claim 19, wherein the capacitance estimating circuitry is configured to estimate the capacitance C_p using the capacitance C_row, the capacitance C_column, and the capacitance C_effective in substantially the following relationship:

21. The device of claim 19, 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.

22. The device of claim 21, further comprising a driver circuit configured to send at least one signal to the display.

23. The device of claim 22, further comprising a controller configured to send at least a portion of the image data to the driver circuit.

24. The device of claim 21, further comprising an image source module configured to send the image data to the processor.

25. The device of claim 24, wherein the image source module comprises at least one of a receiver, transceiver, and transmitter.

26. The device of claim 21, further comprising an input device configured to receive input data and to communicate the input data to the processor.

27. A device for estimating capacitance of one or more selected electrical devices of a plurality of electrical devices, the estimating device comprising:

means for displaying data on the plurality of electrical devices, wherein the plurality of electrical devices are formed in rows and columns and are coupled to a series of row electrodes and a series of column electrodes;

means for driving the data displaying means;

means for determining capacitance C_row between one or more row electrodes coupled to one or more selected electrical devices and a plurality of column electrodes coupled to the displaying means and driven to a common voltage potential, determining capacitance C_column between one or more column electrodes coupled to the one or more selected electrical devices and a plurality of row electrodes coupled to the displaying means and driven to a common voltage potential, and determining capacitance C_effective between the one or more row electrodes and the one or more column electrodes coupled to the one or more selected electrical devices, and providing signals indicative of the determined capacitances; and

means for estimating capacitance C_p of the one or more selected electrical devices based at least on signals received from the determining means indicative of the capacitances C_row, C_column, and C_effective.

28. The device of claim 27, wherein said determining means comprises capacitance measuring circuitry, and wherein said estimating means comprises pixel capacitance compiling logic.

29. The device of claim 27, wherein said displaying means comprises a plurality of interferometric modulators.

30. In an array of electrical devices formed in rows and columns and coupled to a plurality of row electrodes and a plurality of column electrodes, a method of determining an electrical characteristic or operational state of a selected electrical device located in a selected row of the array, in a selected column of the array, the method comprising:

providing a predetermined first value of an electrical characteristic corresponding to a first value of the electrical characteristic between a selected row electrode and a selected column electrode, the plurality of column electrodes being driven to a common voltage and at least a portion of non-selected row electrodes floating, the selected electrical device being coupled to the selected row electrode and the selected column electrode;

providing a predetermined second value of an electrical characteristic corresponding to a second value of the electrical characteristic between the selected row electrode and the selected column electrode, the plurality of row electrodes being driven to a common voltage and at least a portion of non-selected column electrodes floating;

determining a third value of an electrical characteristic between selected row electrode and the selected column electrode, the non-selected column electrodes and row electrodes floating; and

determining a resulting electrical characteristic or operational state of the selected electrical device based at least in part on the first, second, and third values of the electrical characteristic.

31. The method of claim 30, wherein the electrical characteristic is capacitance, and wherein determining capacitance (C_selected—

<sub>display—

device</sub>) of the selected electrical device comprises using the first value (C<sub>first—

value</sub>) the second value (C<sub>second—

value</sub>), and the third value (C<sub>third—

value</sub>) in substantially the following relationship;