Auto-Baseline Determination for Force Sensing

• US 20160179264A1
• Filed: 07/01/2015
• Published: 06/23/2016
• Est. Priority Date: 08/30/2012
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Harley, Jonah A.
• Granted Patent: US 10,108,286 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 2203/04105 Pressure sensors for measuring the pressure or force exerted on the touch surface without providing the touch position
• CPC Class Codes: G06F 3/0414 using force sensing means to determine a position
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/043 using propagating acoustic waves
• CPC Class Codes: G06F 3/044 by capacitive means

Abstract

Determining an applied force of touch on a touch device, in response to a time-varying signal generated by a force of touch sensor. Inferring a measure of force of touch in response to that signal, by determining a peak value of a time derivative of that signal, determining a fraction of that peak value, determining a force of touch corresponding to that peak value, and setting that force as a baseline value for a particular user. Responding to force of touch by the user by comparing against that baseline value. Distinguishing between users having differing baseline values.

Claims

1. Apparatus comprising:

a touch device including one or more force of touch sensors, the force of touch sensors being capable of providing a time-varying signal with respect to a force of touch on the touch device;

one or more processors having access to the time-varying signal, the one or more processors configured to;

determine a baseline value associated with a particular user, based on the time-varying signal;

cause the baseline value for the particular user to be stored in the apparatus;

compare one or more values indicative of a force of touch against the baseline value for that particular user; and

distinguish between a first type of touch having less force of touch than the baseline value for that particular user, and a second type of touch having more force than the baseline value for that particular user.

2. Apparatus as in claim 1, wherein:

the one or more processors have access to instructions, the instructions directing the one or more processors to determine a measure of actual force based on a comparison of one or more values indicative of force of touch against a baseline value for a particular user.

3. Apparatus as in claim 1, wherein:

the one or more processors have access to instructions, the instructions directing the one or more processors

to provide one or more first functions of the touch device in response to the first type of touch; and

to provide one or more second functions of the touch device in response to the second type of touch;

wherein the first functions are distinct from the second functions.

4. Apparatus as in claim 1, wherein:

the baseline value is responsive to a value of the time-varying signal corresponding to a selected fraction of a peak value of a derivative of the time-varying signal.

6. Apparatus as in claim 1, wherein:

the baseline value corresponds to a value of the time-varying signal corresponding to a time after a peak value of the derivative.

8. Apparatus as in claim 1, wherein:

the baseline signal is substantially constant for the particular user, despite a speed of the force of touch on the touch device.

9. Apparatus as in claim 1, wherein:

a derivative of the time-varying signal is based on a first time derivative of the signal.

10. Apparatus as in claim 1, wherein:

the force of touch sensors are capacitive sensors that provide data indicative of a measure of force of touch.

11. Apparatus as in claim 1, wherein:

the force of touch sensors include at least one ultrasound device.

12. Apparatus as in claim 1 wherein:

the force of touch sensors are ultrasound sensors configured to receive an internal reflection of an ultrasound signal.

5. (canceled)

7. (canceled)

13. Apparatus comprising:

a touch device including one or more force of touch sensors, the force of touch sensors being capable of providing a signal responsive to a force of touch;

one or more processors having access to the signal, the one or more processors having access to instructions, the instructions directing the processors to determine a baseline value in response to the signal, wherein the baseline value is substantially stable for a particular user;

wherein the touch device is responsive to whether the force of touch exceeds the baseline value for the particular user.

14. Apparatus as in claim 13, wherein:

the processors have access to instructions directing the processors to distinguish a first particular user from a second particular user in response to the baseline value.

15. Apparatus as in claim 13, wherein:

the baseline value is related to a first time derivative of the signal.

16. Apparatus as in claim 13, wherein:

the baseline value is determined, at least in part, based on a transformation of the signal other than a derivative.

17. Apparatus as in claim 13, wherein:

the baseline signal is substantially constant notwithstanding a speed of the force of touch on the touch device.

18. Apparatus as in claim 13, wherein:

the signal is time-varying and related to a time-varying force of touch, the time-varying force of touch being responsive to a speed at which each particular user presses on the touch device.

19. Apparatus as in claim 18, wherein:

the baseline value is derived from, at least in part, a derivative of the time-varying signal.

20. Apparatus as in claim 18, wherein:

the baseline value is derived from, at least in part an inflection point of the time-varying signal.

21. A method, including operations of:

providing, from one or more force of touch sensors, a time-varying signal with respect to a force of touch on a touch device associated with the force of touch sensors;

by one or more processors coupled to the touch device;

determining a baseline value based on a rate of change of said signal, the baseline value being associated with a particular user;

comparing a signal with respect to a force of touch with the baseline value for that particular user; and

by the touch device, distinguishing between a first type of touch having less force of touch than the baseline value for that particular user, and a second type of touch having more force than the baseline value for that particular user.

22. A method as in claim 21, including operations of:

comparing the time-varying signal, at a selected time, with the baseline value for a selected user; and

based on the comparison, determining a measure of actual force in response to the comparison.

23. A method as in claim 21, including operations of:

providing one or more first functions of the touch device in response to determining a touch is the first type of touch; and

providing one or more second functions of the touch device in response to determining a touch is the second type of touch;

wherein the first functions are distinct from the second functions.

24. A method as in claim 21, wherein:

the baseline value at least partially corresponds to a selected fraction of a peak value of the derivative.

25. A method as in claim 21, wherein:

the baseline value is related to a selected time after a peak value of the derivative.

26. A method as in claim 21, wherein:

the baseline signal is substantially constant for the particular user, despite a speed of the force of touch on the touch device.

27. A method as in claim 21, wherein:

the derivative is a first time derivative of the signal.

28. A method as in claim 21, wherein:

the force of touch sensors are capacitive sensors that provide data indicative of a measure of force of touch.

29. A method as in claim 21, wherein:

the force of touch sensors include at least one ultrasound device.

30. A method as in claim 29, wherein:

the force of touch sensors are ultrasound sensors configured to receive an internal reflection of an ultrasound signal.

31. A method, including operations of:

providing, by one or more force of touch sensors, a signal responsive to a force of touch;

by a processor coupled to the touch device, determining a baseline value in response to the signal, wherein the baseline value is substantially stable for a particular user;

by the touch device, outputting a response based on whether or not the force of touch exceeds the baseline value for the particular user.

32. A method as in claim 31, including operations of:

distinguishing a first particular user from a second particular user, based at least in part on the baseline value.

33. A method as in claim 31, wherein:

the baseline value is determined from a first time derivative of the signal.

34. A method as in claim 31, wherein:

the baseline value is determined from a transformation of the signal other than a derivative.

35. A method as in claim 31, wherein:

the baseline signal is substantially constant notwithstanding a speed of the force of touch on the touch device.

36. A method as in claim 31, wherein:

the signal is time-varying and corresponds to a time-varying force of touch, the time-varying force of touch responsive to a speed at which each particular user presses on the touch device.