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 20090213107A1
• Filed: 02/11/2009
• Published: 08/27/2009
• 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:
  US12/369,652
• Publication Number:
  US 20090213107A1
• Time in Patent Office: Days
• US Class Current: 345/214
• 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 re-using several existing circuitry components and features, thus allowing for integration of the measurement method and its use relatively easily.

Claims

1. A method, comprising:

applying a signal between a first electrode and a second electrode of a display element, wherein the signal is at a level which results in the display element being in a first of a plurality of display states;

applying a second signal between the two said electrodes to transition the display element from one state to another,

measuring an electrical response of the display element in response to the applied second signal;

identifying whether or not the display element reached the desired final state based upon the measured electrical response; and

adjusting the second signal if the display element did not reach the desired final state.

2. The method of claim 1, wherein the first state is an actuated state and the identified error is a failure to relax the display element from the actuated state, the method further comprising adjusting the second signal to a lower level in response to identifying the failure to relax the display element.

3. The method of claim 1, wherein the first state is a relaxed state and the identified error is a failure to actuate the display element, the method further comprising adjusting the second signal to a higher level in response to identifying the failure to actuate the display element.

4. The method of claim 1, wherein the second signal is a bias voltage level which results in the display element remaining in the first state, the first state being an actuated state, the identified error being the display element relaxing, the method further comprising adjusting the second signal to a higher level.

5. The method of claim 1, wherein the second signal is a bias voltage level which results in the display element remaining in the first state, the first state being a released state, the identified error being actuation of the display element, the method further comprising adjusting the drive to a lower level.

6. The method of claim 1, further comprising storing information indicative of the adjusted drive voltage.

7. An apparatus, comprising:

drive circuitry configured to apply a signal between a first electrode and a second electrode of a display element, wherein the signal is at a level which results in the display element being in a first of a plurality of display states;

feedback circuitry configured to measure an electrical response of the display element in response to the applied signal; and

a processor configured control the drive circuitry, receive information indicative of the measured electrical response, identify an error in operation of the display element based upon the measured electrical response, and adjust the drive signal of the display element in response to the identified error.

8. The apparatus of claim 7, wherein the first state is an actuated state and the identified error is a failure to relax the display element from the actuated state, and the processor is further configured to adjust the signal to a lower level in response to identifying the failure to release.

9. The apparatus of claim 7, wherein the first state is a relaxed state and the identified error is a failure to actuate the display element, and the processor is further configured to adjust the signal to a higher level in response to identifying the failure to actuate the display element.

10. The apparatus of claim 7, wherein the signal is a bias voltage level which results in the display element remaining in the first state, the first state being an actuated state, the identified error being the display element relaxing, and the processor being further configured to adjust the signal to a higher level.

11. The apparatus of claim 7, wherein the signal is a bias voltage level which results in the display element remaining in the first state, the first state being a relaxed state, the identified error being actuation of the display element, the processor being further configured to adjust the signal to a lower level.

12. The apparatus of claim 7, wherein at least a portion of the feedback circuitry comprises a portion of the drive circuitry associated with at least one of the first and second electrodes.

13. The apparatus of claim 7, wherein the processor is further configured to store information indicative of the adjusted signal.

14. A display device, comprising:

means for applying a signal between a first electrode and a second electrode of a display element, wherein the signal is at a level which results in the display element being in a first of a plurality of display states;

means for measuring an electrical response of the display element in response to the applied signal;

means for identifying an error in operation of the display element based upon the measured electrical response, and for adjusting the signal in response to the identified error.

15. A display device comprising:

an array of interferometric modulators;

drive circuitry configured to apply a signal between a first electrode and a second electrode of a display element, wherein the signal is at a level that results in the display element being in a first of a plurality of display states;

feedback circuitry configured to measure an electrical response of the display element in response to the applied drive voltage;

a processor configured control the drive circuitry, receive information indicative of the measured electrical response, identify an error in operation of the display element based upon the measured electrical response, and adjust the signal in response to the identified error; and

a memory device configured to communicate with the processor.

16. The display device of claim 15, further comprising a controller configured to send at least a portion of the image data to the drive circuitry.

17. The display device of claim 15, further comprising an image source module configured to send the image data to the processor.

18. The display device of claim 17, wherein the image source module comprises at least one of a receiver, transceiver, and transmitter.

19. The display device of claim 15, further comprising an input device configured to receive input data and to communicate the input data to the processor.