METHOD AND APPARATUS FOR SENSING, MEASUREMENT OR CHARACTERIZATION OF DISPLAY ELEMENTS INTEGRATED WITH THE DISPLAY DRIVE SCHEME, AND SYSTEM AND APPLICATIONS USING THE SAME

• US 20090207159A1
• Filed: 02/11/2009
• Published: 08/20/2009
• Est. Priority Date: 02/11/2008
• Status: Abandoned Application

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Govil, Alok
• Application Number:
  US12/369,620
• Publication Number:
  US 20090207159A1
• Time in Patent Office: Days
• US Class Current: 345/211
• CPC Class Codes: B81B 2201/042 Micromirrors, not used as optical switches
• CPC Class Codes: B81C 99/003 Characterising MEMS devices, e.g. measuring and identifying electrical or mechanical constants
• CPC Class Codes: G09G 2310/066 Waveforms comprising a gently increasing or decreasing portion, e.g. ramp
• CPC Class Codes: G09G 2320/0295 by monitoring each display pixel
• CPC Class Codes: G09G 2320/0693 Calibration of display systems
• 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 3/3466 based on interferometric effect

Abstract

Methods and systems for electrical sensing, measurement and characterization of display elements are described. An embodiment includes integrating the electrical sensing, measurement and characterization with the display drive scheme. This embodiment allows for measurement of DC or operational hysteresis voltages and/or response times of interferometric modulator MEMS devices, for example, to be fully integrated with the display driver IC and/or the display drive scheme. Another embodiment allows these measurements to be performed and used without resulting in display artifacts visible to a human user. Another embodiment allows the measurement circuitry to be integrated with the display driver IC and/or the display drive scheme reusing several existing circuitry components and features, thus allowing for integration of the measurement method.

Claims

1. A method, comprising:

applying a drive signal with a first level between a first electrode and a second electrode of a display element;

ramping the drive signal from the first level to a second level;

monitoring an electrical response of drive circuitry of the display element; and

discontinuing ramping the drive signal in response to the monitored electrical response.

2. The method of claim 1, wherein the display element is in a first state of two or more display states with the drive voltage at the first level, monitoring the electrical response comprises monitoring the electrical response to detect a change of state of the display element from the first state, and discontinuing the ramping of the drive signal comprises discontinuing the ramping of the drive signal at the second voltage level upon detecting the change of state.

3. The method of claim 2, wherein the first state is an actuated state and ramping the drive voltage comprises decreasing a magnitude of the drive voltage.

4. The method of claim 2, wherein the first state is a non-actuated state and ramping the drive voltage comprises increasing a magnitude of the drive voltage.

5. The method of claim 1, wherein ramping the drive voltage further comprises varying a rate of the ramp in a plurality of drive periods, the method further comprising storing information indicative of the magnitude of the second level upon detecting the change of state for each of the drive periods.

6. The method of claim 5, further comprising storing information indicative of the monitored electrical response associated with the varied ramp rates.

7. The method of claim 6, further comprising:

determining at least one operational characteristic of the display element based on the monitored electrical response; and

storing information indicative of the operational characteristic associated with the monitored electrical response.

8. The method of claim 7, further comprising:

determining a drive voltage of the display element based on the stored information to achieve a predetermined operational characteristic.

9. The method of claim 7, wherein the operational characteristic comprises a response time of the display element.

10. An apparatus, comprising:

drive circuitry configured to apply a first drive signal between a first electrode and a second electrode of a display element;

ramp circuitry configured to ramp the level of the drive signal from a first level to a second level; and

feedback circuitry configured to monitor an electrical response of the display element,

wherein the ramp circuitry is further configured to discontinue the ramping of the drive signal in response to the monitored electrical response.

11. The apparatus of claim 10, wherein the display element is in a first state of two or more display states with the drive signal at the first level, the feedback circuitry is further configured to monitor the electrical response to detect a change of state of the display element from the first state and discontinue the ramping of the drive signal at the second voltage level upon detecting the change of state.

12. The apparatus of claim 10, wherein the first state is an actuated state, the second state is a relaxed state and the ramping of the drive voltage comprises decreasing a magnitude of the drive voltage.

13. The apparatus of claim 10, wherein the first state is a non-actuated state, the second state is an actuated state and the ramping of the drive voltage comprises increasing a magnitude of the drive voltage.

14. The apparatus of claim 10, wherein the ramping circuitry is further configured to ramp the drive signal at various rates in a plurality of drive periods, the apparatus further comprising memory configured to store information indicative of a magnitude of the second level upon detecting the change of state for each of the drive periods.

15. The apparatus of claim 14, wherein the memory stores information indicative of the monitored electrical response associated with the varied ramp rates.

16. The apparatus of claim 15, wherein the feedback circuitry is further configured to determine at least one operational characteristic of the display element based on the monitored electrical response, and the memory stores information indicative of the operational characteristic associated with the monitored electrical response.

17. The apparatus of claim 16, further comprising a processor configured to communicate with the memory and control the drive circuitry, the processor configured to determine the drive voltage of the display element based on the stored information to achieve a desired operational characteristic.

18. The apparatus of claim 16, wherein the operational characteristic comprises a response time of the display element.

19. A display device, comprising:

means for applying a drive voltage between a first electrode and a second electrode of a display element;

means for ramping the drive voltage from a first level to a second level; and

means for monitoring an electrical response of the display element,

wherein the ramping means discontinues ramping the drive voltage in response to the monitored electrical response.

20. A display device, comprising:

an array of interferometric modulators;

drive circuitry configured to apply a drive signal between a first electrode and a second electrode of one or more of the interferometric modulators;

ramp circuitry configured to ramp the drive voltage from a first level to a second level;

feedback circuitry configured to monitor an electrical response of the display element and discontinue the ramping of the drive signal in response to the monitored electrical response;

a processor configured to communicate with the array, the processor being configured to process image data; and

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

21. The display device of claim 20, further comprising a controller configured to send at least a portion of the image data to the drive circuitry.

22. The display device of claim 20, further comprising an image source module configured to send the image data to the processor.

23. The display device of claim 22, wherein the image source module comprises at least one of a receiver, transceiver, and transmitter.

24. The display device of claim 20, further comprising an input device configured to receive input data and to communicate the input data to the processor.