Electrical characterization of interferometric modulators

• US 7,289,256 B2
• Filed: 04/01/2005
• Issued: 10/30/2007
• Est. Priority Date: 09/27/2004
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: IDC, LLC
• Inventors: Cummings, William J., Kothari, Manish, Gally, Brian
• Primary Examiner(s): THOMPSON, TIMOTHY J
• Assistant Examiner(s): Fang; Jerry
• Application Number:
  US11/097,511
• Publication Number:
  US 20060077523A1
• Time in Patent Office: 942 Days
• Field of Search: 359/237, 359/238, 359/295, 359/298, 359/290
• US Class Current: 359/238
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26
• 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

Disclosed herein are methods and systems for testing the electrical characteristics of reflective displays, including interferometric modulator displays. In one embodiment, a controlled voltage is applied to conductive leads in the display and the resulting current is measured. The voltage may be controlled so as to ensure that interferometric modulators do not actuate during the resistance measurements. Also disclosed are methods for conditioning interferometric modulator display by applying a voltage waveform that causes actuation of interferometric modulators in the display.

Claims

1. A method of testing an interferometric modulator display, comprising measuring resistance between at least two conductive leads in the display using a force voltage/measure current technique, wherein the conductive leads are used for driving display elements within the display and wherein each lead is electrically coupled to an interferometric modulator display element comprising two reflective surfaces, wherein light reflected from the two reflective surfaces interferometrically produce light in the visible spectrum, and wherein voltage applied during the force voltage/measure current technique is below a voltage required to actuate the display elements.

2. The method of claim 1, further comprising identifying a short between the at least two conductive leads based on said measuring.

3. The method of claim 1, further comprising identifying an open between the at least two conductive leads based on said measuring.

4. The method of claim 1, wherein the forced voltage is applied between adjacent rows of conductive leads.

5. The method of claim 1, wherein the forced voltage is applied between adjacent columns of conductive leads.

6. The method of claim 1, wherein the forced voltage is applied between opposite ends of one or more rows or columns of conductive leads.

7. The method of claim 1, wherein the forced voltage is applied between overlapping rows and columns of conductive leads.

8. A method of measuring resistance between conductive leads in a MEMS display, comprising:

applying a controlled voltage across at least two conductive leads in the display wherein the conductive leads are used for driving display elements within the display, wherein the applied voltage is lower than a voltage required to actuate the display elements, wherein each lead is electrically coupled to an interferometric modulator display element comprising two reflective surfaces, wherein light reflected from the two reflective surfaces interferometrically produce light in the visible spectrum;

measuring current through the leads in response to the applied voltage; and

determining resistance based on the measure current.

9. The method of claim 8, wherein the reflective display comprises interferometric modulators.

10. The method of claim 9, wherein the applied voltage is lower than a voltage required to actuate one or more interferometric modulators in the display.

11. The method of claim 10, wherein the applied voltage is a time-varying voltage waveform.

12. The method of claim 11, wherein the time-varying voltage waveform is an sinusoidal voltage waveform.

13. The method of claim 11, wherein the time-varying voltage is such that it supplies a net zero charge to interferometric modulators in the display.

14. The method of claim 8, further comprising identifying a short between the at least two conductive leads based on said measuring.

15. The method of claim 8, further comprising identifying an open between the at least two conductive leads based on said measuring.

16. The method of claim 8, wherein the controlled voltage is applied between adjacent rows of conductive leads.

17. The method of claim 8, wherein the controlled voltage is applied between adjacent columns of conductive leads.

18. The method of claim 8, wherein the controlled voltage is applied between opposite ends of one or more rows or columns of conductive leads.

19. The method of claim 8, wherein the controlled voltage is applied between overlapping rows and columns of conductive leads.