Determining force applied to an ultrasonic sensor

Patent metadata

Field	Value
Publication number	US-10564778-B2
Application number	US-201916392161-A
Country	US
Kind code	B2
Filing date	Apr 23, 2019
Priority date	Mar 3, 2016
Publication date	Feb 18, 2020
Grant date	Feb 18, 2020

Abstract

In a method for determining force applied to an ultrasonic sensor, ultrasonic signals are emitted from an ultrasonic sensor. A plurality of reflected ultrasonic signals from a finger interacting with the ultrasonic sensor is captured. A first data based at least in part on a first reflected ultrasonic signal of the plurality of reflected ultrasonic signals is compared with a second data based at least in part on a second reflected ultrasonic signal of the plurality of reflected ultrasonic signals. A deformation of the finger during interaction with the ultrasonic sensor is determined based on differences between the first data based at least in part on the first reflected ultrasonic signal and the second data based at least in part on the second reflected ultrasonic signal. A force applied by the finger to the ultrasonic sensor is determined based at least in part on the deformation.

First claim

What is claimed is:

1. A method for determining force applied to a sensor, the method comprising:
receiving a plurality of sensor signals from a sensor, the plurality of sensors signals from a finger interacting with the sensor;
comparing a first data based at least in part on a first sensor signal of the plurality of sensor signals captured at a first time with a second data based at least in part on a second sensor signal of the plurality of sensor signals captured at a second time;
determining a deformation of the finger during interaction with the sensor based on differences between the first data based at least in part on the first sensor signal and the second data based at least in part on the second sensor signal; and
determining a force applied by the finger to the sensor based at least in part on the deformation.

2. The method of claim 1 , wherein the first data comprises at least one characteristic of the first sensor signal and the second data comprises the at least one characteristic of the second sensor signal.

3. The method of claim 2 , wherein the at least one characteristic represents a feature of the finger derived from at least one of the first sensor signal and the second sensor signal.

4. The method of claim 2 , wherein the first data and the second data represent the at least one characteristic as a function of depth.

5. The method of claim 4 , wherein the first data represents the at least one characteristic as a function of depth for at least one position of the finger.

6. The method of claim 2 , wherein the determining a deformation of the finger during the interaction with the sensor is based at least in part on a difference between the at least one characteristic of the first data and the at least one characteristic of the second data.

7. The method of claim 1 , wherein the determining a deformation of the finger during the interaction with the sensor is based on at least one of a deformation of a feature of the finger, and a displacement of a feature of the finger.

8. The method of claim 7 , wherein the feature of the finger comprises a ridge/valley of the finger.

9. The method of claim 1 , wherein the first data comprises at least one image and the second data comprises at least one image.

10. The method of claim 9 , wherein the first data comprises a plurality of images and the second data comprises a plurality of images, and wherein each image of the plurality of images corresponds to a different depth.

11. The method of claim 9 , wherein the at least one image of the first data and the at least one image of the second data represent a cross section of the finger.

12. The method of claim 9 , wherein the first data comprises an image of a first dermal layer of the finger, and the second data comprises an image of a second dermal layer of the finger.

13. The method of claim 12 , wherein the determining a deformation of the finger during interaction with the sensor comprises:
determining a deformation of at least one of the first dermal layer and the second dermal layer.

14. The method of claim 1 , wherein determining a deformation of the finger during interaction with the sensor comprises:
determining a change of curvature of a dermal layer.

15. The method of claim 1 , wherein the determining a force applied by the finger to the sensor comprises:
determining at least one of a normal component of the force and lateral component of the force.

16. The method of claim 1 , wherein the determining a force applied by the finger to the sensor comprises:
determining at least one of a maximum of the force, a magnitude of the force and a direction of the force during a time window.

17. The method of claim 16 , wherein the time window comprises the finger contacting the sensor until the finger separates from the sensor.

18. The method of claim 1 , further comprising:
using the force to provide navigation functionality on a display of an electronic device communicatively coupled to the sensor.

19. The method of claim 18 , wherein the using the force to provide navigation functionality on a display of an electronic device communicatively coupled to the sensor comprises:
comparing a magnitude of the force to a threshold;
provided the magnitude of the force does not exceed the threshold, using the sensor in a first navigation mode, wherein the first navigation mode determines motion based at least in part on a translation of an outer surface of the finger relative to the sensor; and
provided the magnitude of the force exceeds the threshold, using the sensor in a second navigation mode, wherein the second navigation mode determines motion based at least in part on a direction of the force.

20. The method of claim 18 , wherein the navigation functionality is activated automatically responsive to an application executing on the electronic device.

21. The method of claim 1 , further comprising:
receiving sensor data from another sensor;
combining the force with the sensor data; and
modifying the force based on the sensor data.

22. The method of claim 21 , wherein the another sensor is a motion sensor and wherein the sensor data comprises a change in orientation of the sensor based on the force applied by the finger to the sensor.

23. The method of claim 21 , wherein the combining the force with the sensor data is based at least in part on a context of the sensor data.

24. The method of claim 21 , wherein the another sensor is activated for determining the sensor data responsive to the finger interacting with the sensor.

25. The method of claim 1 , further comprising:
calibrating the sensor, the calibrating comprising at least one of:
determining a maximum of the force applied by the finger;
identifying a suitable feature of the finger to determine the force;
identifying a suitable dermal layer to determine the force; and
determining a relationship between the deformation and the force.

26. The method of claim 1 , wherein the sensor is an ultrasonic sensor.

27. An electronic device comprising:
a sensor for generating sensor signals responsive to a finger interacting with the sensor;
a processor capable of determining force applied to the sensor by the finger, wherein the processor is operable to:
compare a first data based at least in part on a first sensor signal of the sensor signals with a second data based at least in part on a second sensor signal of the sensor signals;
determine a deformation of the finger during interaction with the sensor based on differences between the first data based at least in part on the first sensor signal and the second data at least in part based on the second sensor signal; and
determine a force applied by the finger to the sensor based at least in part on the deformation.

28. The electronic device of claim 27 , wherein the processor is further operable to detect a fingerprint of the finger based at least in part on one of the first data and the second data.

29. The electronic device of claim 27 , wherein the processor is further operable to adapt beam forming of the sensor signals to a predetermined depth into the finger.

30. The electronic device of claim 27 , further comprising:
a display device, wherein the processor is further operable to provide navigation functionality on the display device based at least in part on the force.

Assignees

• Invensense Inc

Inventors

• Medina Eitan
• Abdi Behrooz
• Massih Sam
• Fayolle Romain
• Tang Hao-Yen

Classifications

• G01L1/16

  using properties of piezoelectric devices · CPC title

• G06F3/043

  using propagating acoustic waves · CPC title

• G06F3/0436 Primary

  in which generating transducers and detecting transducers are attached to a single acoustic waves transmission substrate · CPC title

• G06K9/0002

  Physics · mapped topic

• G06F3/0416 Primary

  Control or interface arrangements specially adapted for digitisers · CPC title