PRESSURE MEASUREMENT USING A MEMS DEVICE

• US 20110071775A1
• Filed: 11/30/2010
• Published: 03/24/2011
• Est. Priority Date: 06/18/2008
• Status: Abandoned Application

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Khazeni, Kasra
• Application Number:
  US12/956,611
• Publication Number:
  US 20110071775A1
• Time in Patent Office: Days
• US Class Current: 702/52
• CPC Class Codes: G01L 9/0073 using a semiconductive diaphragm
• CPC Class Codes: G01L 9/0086 using variations in capacitance

Abstract

A device to measure pressure is disclosed. In one embodiment, the device includes at least one element with two layers separated by a space which changes over a variable time period in response to a voltage applied across the two layers. The time period may be measured and is indicative of the ambient pressure about the device.

Claims

1. A device for measuring pressure comprising:

at least one element comprising two layers separated by a space, wherein a dimension of the space changes in response to an applied stimulus; and

a processor configured to determine a time period over which the dimension of the space changes from a first dimension to a second dimension, and determine, based on the determined time period, an ambient pressure about the device.

2. The device of claim 1, wherein the at least one element comprises at least one microelectromechanical systems (MEMS) element.

3. The device of claim 1, wherein the at least one element comprises at least one interferometric modulator.

4. The device of claim 1, wherein the at least one element comprises a plurality of elements comprising two layers, and the processor is configured to determine a plurality of respective time periods, and determine, based on the determined time periods, an ambient pressure about the device.

5. The device of claim 1, wherein the processor is further configured to apply a stimulus to the at least one element.

6. The device of claim 5, wherein the stimulus comprises an applied voltage across the two layers.

7. The device of claim 1, further comprising a display configured to display the determined pressure.

8. The device of claim 1, wherein the processor is further configured to determine an altitude based on the determined ambient pressure, further comprising a display configured to display the determined altitude.

9. The device of claim 1, wherein the processor is configured to determine the time period by measuring an electrical current induced by a motion of at least one of the layers.

10. The device of claim 9, wherein the processor is configured to determine the time period by determining a time between when a voltage is applied across the two layers and when the electrical current reaches a relative maximum.

11. The device of claim 9, wherein the processor is configured to determine the time period by determining a time between a first time and a second time, the first time and second time each being when the electrical current reaches a predetermined percentage of a relative maximum.

12. The device of claim 1, wherein the processor is configured to determine the time period by measuring a capacitance across the two layers.

13. The device of claim 1, wherein the processor is configured to determine the time period as a release time or actuation time of the at least one element.

14. A method of measuring pressure comprising:

applying a stimulus to an element comprising two layers separated by a space, wherein a dimension of the space changes in response to the stimulus;

determining a time period over which the dimension of the space changes from a first dimension to a second dimension; and

determining, based on the determined time period, an ambient pressure about the element.

15. The method of claim 14, wherein applying the stimulus comprises applying a voltage across the two layers.

16. The method of claim 14, wherein applying the stimulus comprises applying the stimulus to a microelectromechanical systems (MEMS) element.

17. The method of claim 14, wherein applying the stimulus comprises applying a voltage across two layers of an interferometric modulator.

18. The method of claim 14, further comprising a displaying the determined pressure.

19. The method of claim 14, further comprising determining an altitude based on the determined ambient pressure and displaying the determined altitude.

20. The method of claim 14, wherein determining the time period comprises measuring an electrical current induced by a motion of at least one of the layers.

21. The method of claim 20, wherein determining the time period comprises determining a time between when a voltage is applied across the two layers and when the electrical current reaches a relative maximum.

22. The method of claim 20, wherein determining the time period comprises determining a time between a first time and a second time, the first time and second time each being when the electrical current reaches a predetermined percentage of a relative maximum.

23. The method of claim 14, wherein determining the time period comprises determining the capacitance across the two layers.

24. The method of claim 14, wherein determining the time period comprises determining a release time or actuation time of the element.

25. A system for measuring pressure comprising:

means for applying a stimulus to an element comprising two layers separated by a space, wherein a dimension of the space changes in response to the stimulus;

means for determining a time period over which the dimension of the space changes from a first dimension to a second dimension; and

means for determining, based on the determined time period, an ambient pressure about the element.

26. The system of claims 25, wherein the means for applying the stimulus comprises means for applying a voltage across the two layers.

27. The system of claim 25, wherein the means for applying the stimulus comprises means for applying the stimulus to a microelectromechanical systems (MEMS) element.

28. The system of claim 25, wherein the means for applying the stimulus comprises means for applying a voltage across two layers of an interferometric modulator.

29. The system of claim 25, further comprising means for displaying the determined pressure.

30. The system of claim 25, further comprising means for determining an altitude based on the determined ambient pressure and means for displaying the determined altitude.

31. The system of claim 25, wherein the means for determining the time period comprises means for measuring an electrical current induced by a motion of at least one of the layers.

32. The system of claim 31, wherein the means for determining the time period comprises means for determining a time between when a voltage is applied across the two layers and when the electrical current reaches a relative maximum.

33. The system of claim 31, wherein the means for determining the time period comprises means for determining a time between a first time and a second time, the first time and second time each being when the electrical current reaches a predetermined percentage of a relative maximum.

34. The system of claim 25, wherein the means for determining the time period comprises determining the capacitance across the two layers.

35. The system of claim 25, wherein the means for determining the time period comprises determining a release time or actuation time of the element.

36. The system of claim 25, wherein at least one of the means for applying a stimulus to an element, the means for means for determining a time period, and the means for determining an ambient pressure about the element comprises a processor.

37. A non-transitory computer-readable storage medium comprising instructions which, when executed by an apparatus, cause the apparatus to:

apply a stimulus to an element comprising two layers separated by a space, wherein a dimension of the space changes in response to the stimulus;

determine a time period over which the dimension of the space changes from a first dimension to a second dimension; and

determine, based on the determined time period, an ambient pressure about the element.

38. The non-transitory computer-readable storage medium of claim 37, wherein the instructions which cause the apparatus to apply a stimulus comprise instructions which cause the apparatus to apply a voltage across the two layers.

39. The non-transitory computer-readable storage medium of claim 37, further comprising instructions, which when executed by the apparatus, cause the apparatus to display the determined pressure.

40. The non-transitory computer-readable storage medium of claim 37, wherein the instructions which cause the apparatus to determine a time period comprise instructions, which cause the apparatus to determining a time between when a voltage is applied across the two layers and when the electrical current reaches a relative maximum.