Blockage detection for a microelectromechanical systems sensor

Patent metadata

Field	Value
Publication number	US-9924288-B2
Application number	US-201414527235-A
Country	US
Kind code	B2
Filing date	Oct 29, 2014
Priority date	Oct 29, 2014
Publication date	Mar 20, 2018
Grant date	Mar 20, 2018

Abstract

Systems and techniques for detecting blockage associated with a microelectromechanical systems (MEMS) microphone of a device are presented. The device includes a MEMS acoustic sensor and a processor. The MEMS acoustic sensor is contained in a cavity within the device. The processor is configured to detect a blockage condition associated with an opening of the cavity that contains the MEMS acoustic sensor.

First claim

What is claimed is:

1. A device, comprising:
a microelectromechanical systems (MEMS) acoustic sensor contained in a cavity within the device;
an acoustic signal generator configured to generate a test acoustic signal associated with a test waveform; and
a processor configured to detect a blockage condition associated with an opening of the cavity that contains the MEMS acoustic sensor based on analysis of a resonant peak of an output associated with the MEMS acoustic sensor in response to the test acoustic signal being received via the opening of the cavity that contains the MEMS acoustic sensor, and to modify functionality of the MEMS acoustic sensor in response to a determination that the resonant peak satisfies a defined criterion.

2. The device of claim 1 , wherein the processor is configured to detect the blockage condition based on at least one other characteristic of the output associated with the MEMS acoustic sensor in response to the test signal being received via the opening of the cavity that contains the MEMS acoustic sensor.

3. The device of claim 1 , wherein the acoustic signal generator is configured to generate the test acoustic signal by altering one or more electrical conditions associated with the acoustic signal generator.

4. The device of claim 1 , wherein the MEMS acoustic sensor is a first MEMS acoustic, and wherein the acoustic signal generator is a second MEMS acoustic sensor configured to generate the test acoustic signal by resonating a diaphragm associated with the second MEMS acoustic sensor.

5. The device of claim 1 , wherein the processor is configured to detect the blockage condition based on frequency response of the MEMS acoustic sensor in response to the test acoustic signal.

6. The device of claim 1 , wherein the processor is configured to detect the blockage condition based on a comparison between at least one predetermined characteristic of the MEMS acoustic sensor and at least one characteristic of the MEMS acoustic sensor that is determined in response to the test acoustic signal.

7. The device of claim 1 , wherein the test acoustic signal is an ultrasonic signal.

8. The device of claim 1 , wherein the processor is configured to detect the blockage condition based on at least one other characteristic of the output in response to the test acoustic signal.

9. The device of claim 1 , wherein the processor is configured to detect the blockage condition based on a change in sensitivity of the MEMS acoustic sensor in response to the test acoustic signal being received via the opening of the cavity that contains the MEMS acoustic sensor, and wherein the sensitivity is indicative of a ratio of the output associated with the MEMS acoustic sensor to an input pressure.

10. The device of claim 1 , wherein the processor is configured to detect the blockage condition based on a shift of the resonant peak of the output associated with the MEMS acoustic sensor in response to the test acoustic signal being received via the opening of the cavity that contains the MEMS acoustic sensor.

11. The device of claim 1 , wherein the processor is configured to detect the blockage condition based on a proximity sensor associated with the MEMS acoustic sensor.

12. The device of claim 1 , wherein the processor is configured to detect the blockage condition based on a voltage value with respect to a Pascal value associated with the MEMS acoustic sensor.

13. A method comprising:
receiving a test acoustic signal associated with a test waveform via an opening of a cavity that encloses a microelectromechanical systems (MEMS) acoustic sensor; and
detecting, in response to the test acoustic signal received via the opening of the cavity that encloses the MEMS acoustic sensor, a blockage condition associated with the MEMS acoustic sensor based on analysis of a resonant peak of an output signal generated by the MEMS acoustic sensor in response to the test acoustic signal received via the opening of the cavity that encloses the MEMS acoustic sensor; and
modifying functionality of the MEMS acoustic sensor in response to a determination that the resonant peak satisfies a defined criterion.

14. The method of claim 13 , wherein the detecting the blockage condition associated with the MEMS acoustic sensor comprises detecting the blockage condition associated with the MEMS acoustic sensor based on a change in sensitivity of the MEMS acoustic sensor in response to the test acoustic signal.

15. The method of claim 13 , wherein the detecting the blockage condition associated with the MEMS acoustic sensor comprises detecting the blockage condition associated with the MEMS acoustic sensor based on a shift of the resonant peak of the output signal generated by the MEMS acoustic sensor in response to the test acoustic signal received via the opening of the cavity that encloses the MEMS acoustic sensor.

16. The method of claim 13 , wherein the detecting the blockage condition associated with the MEMS acoustic sensor comprises detecting the blockage condition associated with the MEMS acoustic sensor based on at least one proximity sensor associated with the opening.

17. The method of claim 13 , further comprising:
generating the test acoustic signal via an acoustic signal generator.

18. The method of claim 17 , wherein the generating the test acoustic signal comprises generating an ultrasonic signal via the acoustic signal generator.

19. The method of claim 17 , wherein the receiving the test acoustic signal comprises receiving an ultrasonic signal via the opening of the cavity that encloses the MEMS acoustic sensor.

20. A system, comprising:
a first microelectromechanical systems (MEMS) microphone contained in a first cavity within a device and configured to receive a test acoustic signal associated with a test waveform;
a second MEMS microphone contained in a second cavity within the device; and
at least one processor configured to detect a blockage condition associated with a least the first MEMS microphone based on analysis of a resonant peak of an output signal associated with the first MEMS microphone in response to the test acoustic signal being received via an opening of the first cavity that contains the first MEMS microphone, and to modify functionality of the first MEMS acoustic sensor in response to a determination that the resonant peak satisfies a defined criterion.

21. The system of claim 20 , wherein the at least one processor is configured to detect the blockage condition based on a change in a frequency response pattern of the first MEMS microphone in response to the test acoustic signal being received via the opening of the first cavity that contains the first MEMS microphone.

22. The system of claim 20 , wherein the at least one processor is configured to detect the blockage condition based on a proximity sensor associated with the first MEMS microphone.

23. The system of claim 20 , wherein the second MEMS microphone is configured to generate the test acoustic signal.

Assignees

• Invensense Inc

Inventors

• Cagdaser Baris
• Berger Renata Melamud
• Oliaei Omid
• Khenkin Aleksey S

Classifications

• H04R2499/11

  Transducers incorporated or for use in hand-held devices, e.g. mobile phones, PDA's, camera's · CPC title

• H04R2460/11

  Aspects relating to vents, e.g. shape, orientation, acoustic properties in ear tips of hearing devices to prevent occlusion · CPC title

• H04R29/004 Primary

  for microphones (H04R29/007 takes precedence) · CPC title

• H04R3/00

  Circuits for transducers (arrangements for producing a reverberation or echo sound G10K15/08; amplifiers H03F) · CPC title

• H04R25/305

  Self-monitoring or self-testing · CPC title