Low voltage driver scheme for interferometric modulators

• US 8,736,590 B2
• Filed: 01/20/2010
• Issued: 05/27/2014
• Est. Priority Date: 03/27/2009
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Lewis, Alan G., Mignard, Marc Maurice, Chui, Clarence, Van Lier, Wilhelmus Johannes Robertus, Todorovich, Mark M., Cummings, William
• Primary Examiner(s): Haley, Joseph
• Assistant Examiner(s): ILUYOMADE, IFEDAYO B
• Application Number:
  US12/690,391
• Publication Number:
  US 20100245311A1
• Time in Patent Office: 1,588 Days
• Field of Search: None
• US Class Current: 345/208
• CPC Class Codes: G09G 2300/0473 Use of light emitting or modulating elements having two or more stable states when no power is applied
• CPC Class Codes: G09G 2300/06 Passive matrix structure, i.e. with direct application of both column and row voltages to the light emitting or modulating elements, other than LCD or OLED
• CPC Class Codes: G09G 2310/0251 Precharge or discharge of pixel before applying new pixel voltage
• CPC Class Codes: G09G 2310/0254 Control of polarity reversal in general, other than for liquid crystal displays
• CPC Class Codes: G09G 2310/04 Partial updating of the display screen
• CPC Class Codes: G09G 2310/06 Details of flat display driving waveforms
• CPC Class Codes: G09G 2320/0252 Improving the response speed
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/2003 Display of colours specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 3/3466 based on interferometric effect

Abstract

A method of driving electromechanical devices such as interferometric modulators includes applying a voltage along a common line to release the electromechanical devices along the common line, followed by applying an address voltage along the common line to actuate selected electromechanical devices along the common line based on voltages applied along segment lines. Hold voltages may be applied along common lines between applications of release and address voltages, and the segment voltages may be selected to be sufficiently small that the segment voltages will not affect the state of the electromechanical devices along other common lines not being written to.

Claims

1. A method of driving an array of display elements, the method comprising:

applying a voltage waveform to at least a portion of an array of display elements, the voltage waveform comprising a frame write waveform and an hold sequence waveform, wherein substantial percentages of the frame write waveform have values substantially equal to a release voltage, a hold voltage, and an address voltage, and wherein a substantial percentage of the hold sequence waveform comprises an adjusted hold voltage substantially different from the hold voltage and wherein the adjusted hold voltage is predetermined so as to provide a desired white balance when a constant segment voltage is applied on one or more segment lines.

2. The method of claim 1, wherein the adjusted hold voltage is predetermined based on a capacitance of at least one of the display elements.

3. The method of claim 1, wherein the adjusted hold voltage is predetermined so as to provide a desired optical response.

4. The method of claim 1, further comprising applying a first segment voltage waveform to a crossing portion of the array, the crossing portion of the array at least partially overlapping the portion of the array.

5. The method of claim 4, wherein the first segment voltage waveform comprises a segment frame write waveform and a segment hold sequence waveform, wherein substantial percentages of the segment frame write waveform comprise values substantially equal to a the first segment voltage, wherein a substantial percentage of the segment hold sequence waveform comprises a value substantially equal to an intermediate voltage, and wherein the intermediate voltage is substantially different from the first segment voltage.

6. A method of driving an array, the method comprising:

respectively applying a first, second, and third voltage waveform to a first, second, and third portion of an array, wherein each of the first, second, and third voltage waveforms respectively comprises a first, second, and third frame write waveform and a first, second, and third hold sequence waveform, and wherein each of the first, second, and third portions of the array is associated with a different color primary;

wherein substantial percentages of the first frame write waveform have values substantially equal to a first release voltage, a first hold voltage, and a first address voltage;

wherein substantial percentages of the second frame write waveform have values substantially equal to a second release voltage, a second hold voltage, and a second address voltage;

wherein substantial percentages of the third frame write waveform have values substantially equal to a third release voltage, a third hold voltage, and a third address voltage;

wherein a substantial percentage of each of the first, second, and third hold sequence waveforms has a value substantially equal to, respectively, a first, second, and third adjusted hold voltage;

wherein the first adjusted hold voltage is substantially different from the first hold voltage, the second adjusted hold voltage is substantially different from the second hold voltage, and the third adjusted hold voltage is substantially different from the third hold voltage; and

wherein at least one of the adjusted hold voltages is predetermined so as to provide a desired white balance when a constant segment voltage is applied on one or more segment lines.

7. The method of claim 6, wherein at least one of the adjusted hold voltages is predetermined so as to provide a desired optical response.

8. The method of claim 7, wherein at least one of the adjusted hold voltages is predetermined such that the color reflected by the first, second, and third portions of the array is at a particular white point.

9. The method of claim 6, wherein the first, second, and third portions of the array are respectively associated with red, green, and blue.

10. The method of claim 6, wherein the frame write waveforms are based at least in part on image update data.

11. The method of claim 6, further comprising applying first segment voltage waveforms to a plurality of crossing portions of the array, each crossing portion of the array at least partially overlapping the first, second, and third portion of the array.

12. The method of claim 11, wherein each of the first segment voltage waveforms comprises a segment frame write waveform and a segment hold sequence waveform, wherein substantial percentages of each of the segment frame write waveforms comprise values substantially equal to a first segment voltage, wherein a substantial percentage of each of the segment hold sequence waveforms comprises a value substantially equal to an intermediate voltage, and wherein the intermediate voltage is substantially different from the first segment voltage.

13. A system for driving an array, the system comprising:

a circuit configured to generate at least a first, second, and third voltage waveform, wherein each of the first, second, and third voltage waveforms respectively comprises a first, second, and third frame write waveform and a first, second, and third hold sequence waveform,

wherein substantial percentages of the first frame write waveform have values substantially equal to a first release voltage, a first hold voltage, and a first address voltage,

wherein substantial percentages of the second frame write waveform have values substantially equal to a second release voltage, a second hold voltage, and a second address voltage,

wherein substantial percentages of the third frame write waveform have values substantially equal to a third release voltage, a third hold voltage, and a third address voltage,

wherein a substantial percentage of each of the first, second, and third hold sequence waveforms has a value substantially equal to, respectively, a first, second, and third adjusted hold voltage, and

wherein the first adjusted hold voltage is substantially different from the first hold voltage, the second adjusted hold voltage is substantially different from the second hold voltage, or the third adjusted hold voltage is substantially different from the third hold voltage;

wherein the circuit is further configured to respectively apply the first, second, and third voltage waveforms to a first, second, and third portions of an array, wherein each of the first, second, and third portions of the array is associated with a different primary color; and

wherein at least one of the adjusted hold voltages is predetermined so as to provide a desired white balance when a constant segment voltage is applied on one or more segment lines.

14. The system of claim 13, wherein the circuit is further configured to receive image data and to generate the first, second, and third voltage waveforms based at least in part on the image data.

15. The system of claim 13, wherein the array is an array of interferometric modulators.

16. A system for driving an array, the system comprising:

means for generating at least a first, second, and third voltage waveform, wherein each of the first, second, and third voltage waveforms respectively comprises a first, second, and third frame write waveform and a first, second, and third hold sequence waveform,

wherein substantial percentages of the first frame write waveform have values substantially equal to a first release voltage, a first hold voltage, and a first address voltage,

wherein substantial percentages of the second frame write waveform have values substantially equal to a second release voltage, a second hold voltage, and a second address voltage,

wherein substantial percentages of the third frame write waveform have values substantially equal to a third release voltage, a third hold voltage, and a third address voltage,

wherein a substantial percentage of each of the first, second, and third hold sequence waveforms has a value substantially equal to, respectively, a first, second, and third adjusted hold voltage,

wherein the first adjusted hold voltage is substantially different from the first hold voltage, the second adjusted hold voltage is substantially different from the second hold voltage, or the third adjusted hold voltage is substantially different from the third hold voltage;

means for respectively applying the first, second, and third voltage waveforms to a first, second, and third portions of an array, wherein each of the first, second, and third portions of the array is associated with a different color primary; and

wherein at least one of the adjusted hold voltages is predetermined so as to provide a desired white balance when a constant segment voltage is applied on one or more segment lines.

17. The system of claim 16, further comprising means for applying a first segment voltage waveforms to a plurality of crossing portions of the array, each crossing portion of the array at least partially overlapping the first, second, and third portion of the array.

18. The system of claim 17, wherein each of the first segment voltage waveforms comprise a segment frame write waveform and an segment hold sequence waveform, wherein a substantial percentage of each of the segment frame write waveforms comprises a value substantially equal to a first segment voltage, wherein a substantial percentage of each of the segment hold sequence waveforms comprises a value substantially equal to an intermediate voltage, wherein the intermediate voltage is substantially different from the first segment voltage.

19. A non-transitory computer-readable storage medium comprising instructions which, when executed by one or more processors, causes a computer to perform a method of driving an array, the method comprising:

respectively applying a first, second, and third voltage waveform to a first, second, and third portion of an array, wherein each of the first, second, and third voltage waveforms respectively comprises a first, second, and third frame write waveform and a first, second, and third hold sequence waveform, and wherein each of the first, second, and third portions of the array is associated with a different color primary;

wherein substantial percentages of the first frame write waveform have values substantially equal to a first release voltage, a first hold voltage, and a first address voltage;

wherein substantial percentages of the second frame write waveform have values substantially equal to a second release voltage, a second hold voltage, and a second address voltage;

wherein substantial percentages of the third frame write waveform have values substantially equal to a third release voltage, a third hold voltage, and a third address voltage;

wherein a substantial percentage of each of the first, second, and third hold sequence waveforms has a value substantially equal to, respectively, a first, second, and third adjusted hold voltage;

wherein the first adjusted hold voltage is substantially different from the first hold voltage, the second adjusted hold voltage is substantially different from the second hold voltage, or the third adjusted hold voltage is substantially different from the third hold voltage; and

wherein at least one of the adjusted hold voltages is predetermined so as to provide a desired white balance when a constant segment voltage is applied on one or more segment lines.

20. The method of claim 1, wherein the hold voltage and the adjusted hold voltage are within a same hysteresis window of the portion of the array of display elements.

21. The non-transitory computer-readable storage medium of claim 19, wherein at least one of the adjusted hold voltages is predetermined so as to provide a desired optical response.

22. The non-transitory computer-readable storage medium of claim 21, wherein at least one of the adjusted hold voltages is predetermined such that the color reflected by the first, second, and third portions of the array is at a particular white point.

23. The non-transitory computer-readable storage medium of claim 19, wherein the first, second, and third portions of the array are respectively associated with red, green, and blue.

24. The non-transitory computer-readable storage medium of claim 19, wherein the frame write waveforms are based at least in part on image update data.

25. The non-transitory computer-readable storage medium of claim 19, the method further comprising applying first segment voltage waveforms to a plurality of crossing portions of the array, each crossing portion of the array at least partially overlapping the first, second, and third portion of the array.

26. The non-transitory computer-readable storage medium of claim 25, wherein each of the first segment voltage waveforms comprises a segment frame write waveform and a segment hold sequence waveform, wherein substantial percentages of each of the segment frame write waveforms comprise values substantially equal to a first segment voltage, wherein a substantial percentage of each of the segment hold sequence waveforms comprises a value substantially equal to an intermediate voltage, and wherein the intermediate voltage is substantially different from the first segment voltage.