Capacitive sensing with interpolating force-sensitive resistor array

Patent metadata

Field	Value
Publication number	US-9740341-B1
Application number	US-84649710-A
Country	US
Kind code	B1
Filing date	Jul 29, 2010
Priority date	Feb 26, 2009
Publication date	Aug 22, 2017
Grant date	Aug 22, 2017

Abstract

An combination interpolating force sensitive resistor (IFSR) array touch sensor and capacitive touch sensor, or a modified IFSR sensor, is configured to detect touches resistively and capacitvely. By comparing resistive and capacitive signals, touches may be accurately characterized. The IFSR array may also be used in conjunction with an active stylus to determine a position of the active stylus relative to the IFSR array.

First claim

What is claimed is:

1. A device comprising:
an interpolating force-sensitive resistor array touch sensor comprising two layers, a first layer comprising a column of electrodes and a second layer comprising a row of electrodes and a resistive material filling gaps between the electrodes of the first layer and the electrodes of the second layer to act as a linear resistor, the resistive material having an electrical resistance that varies in relation to a force applied to the resistive material; and
non-transitory computer-readable media storing instructions that, when executed by one or more processors, cause the one or more processors to perform operations comprising:
receiving voltage data from a touch controller coupled to the interpolating force-sensitive resistor array touch sensor;
generating a temporal voltage profile based at least in part on the voltage data, the temporal voltage profile indicating a capacitive effect and a resistive effect over time on the interpolating force-sensitive resistor array touch sensor from a touch input; and
analyzing the temporal voltage profile so as to determine that the temporal voltage profile corresponds to at least one of a resistive touch input or a capacitive touch input.

2. The device of claim 1 , wherein the touch controller is configured to characterize the touch input as a finger or non-finger based at least in part upon the temporal voltage profile.

3. The device of claim 1 , wherein generating the temporal voltage profile comprises:
pulsing a voltage to a first portion of the interpolating force-sensitive resistor array touch sensor; and
measuring the voltage over time at a second portion of the force-sensitive resistor array.

4. A device comprising:
an interpolating force-sensitive resistor array touch sensor comprising:
a first layer comprising a column of electrodes;
a second layer comprising a row of electrodes; and
a resistive material which fills gaps between the electrodes of the first layer and the electrodes of the second layer and having an electrical resistance that is altered at least in part by a force applied to the resistive material; and

non-transitory computer-readable media storing instructions that, when executed by one or more processors, cause the one or more processors to perform operations comprising:
receiving voltage data from a touch controller coupled to the interpolating force-sensitive resistor array touch sensor;
generating a temporal voltage profile based at least in part on the voltage data, the temporal voltage profile indicating a capacitive effect and a resistive effect over time on the interpolating force-sensitive resistor array touch sensor from a touch input; and
analyzing the temporal voltage profile so as to determine that the temporal voltage profile corresponds to at least one of a resistive touch input or a capacitive touch input.

5. The device of claim 4 , wherein the resistive material acts as a linear resistor which allows the touch controller to interpolate a location of the touch input between intersections of the electrode of the first layer and between intersections of the electrodes of the second layer.

6. The device of claim 4 , wherein the touch controller characterizes the touch input as corresponding to a finger or non-finger based at least in part upon a comparison of the resistive effect and the capacitive effect.

7. A method comprising:
pulsing a voltage to a first portion of an interpolating force-sensitive resistor array touch sensor comprising a first layer comprising a column of electrodes, a second layer comprising a row of electrodes, and a resistive material which fills gaps between the electrodes of the first layer and the electrodes of the second layer and having an electrical resistance that varies based at least in part on a pressure applied to the resistive material;
measuring a voltage generated by a signal associated with a touch over time at a second portion of the force-sensitive resistor array;
generating a temporal voltage profile from the measured voltage over time, wherein the temporal voltage profile comprises capacitive effects between the electrodes of the first layer and the electrodes of the second layer and resistive effects between the electrodes of the first layer and the electrodes of the second layer; and
analyzing the temporal voltage profile so as to determine that the temporal voltage profile corresponds to at least one of a resistive touch input or a capacitive touch input.

8. The method of claim 7 , further comprising characterizing the touch input at the touch sensor, the characterizing comprising:
determining when a voltage spike associated with capacitive coupling of a portion of the array is present within the temporal voltage profile;
determining when a steady state voltage over a pre-determined period of time associated with a resistive contact within a portion of the array is present within the temporal voltage profile;
when the voltage spike and the steady state voltage are present, categorize the touch input as a user touch; and
when the voltage spike is absent and the steady state voltage is present, categorize the touch input as a non-user touch.

9. A device comprising:
an interpolating force-sensitive resistor array touch sensor comprising a first layer comprising a column of electrodes, a second layer comprising a row of electrodes, and a resistive material which fills gaps between the electrodes of the first layer and the electrodes of the second layer and having an electrical resistance that changes based at least in part on a pressure applied to the resistive material; and
non-transitory computer-readable media storing instructions that, when executed by one or more processors, cause the one or more processors to perform operations comprising:
receiving voltage data from a touch controller coupled to the interpolating force-sensitive resistor array touch sensor;
generating a temporal voltage profile based at least in part on the voltage data, the temporal voltage profile indicating a capacitive effect and a resistive effect over time on the interpolating force-sensitive resistor array touch sensor from a touch input; and
analyzing the temporal voltage profile so as to determine that the temporal voltage profile corresponds to at least one of a resistive touch input or a capacitive touch input.

10. The device of claim 9 , wherein the touch controller is further configured to characterize the touch input as corresponding to a finger or a non-finger based at least in part upon a comparison of the resistive effect and the capacitive effect associated with the touch input.

11. The device of claim 9 , the operations further comprising:
communicating with an active stylus; and
determining a position of the active stylus relative to the touch sensor.

12. The device of claim 11 , wherein the touch sensor emits a signal and the active stylus is configured to receive the signal and determine a position relative to the touch sensor.

13. The device of claim 11 , wherein the touch sensor emits the signal at a particular time and receives from the active stylus an indication that the signal was received at the particular time.

14. The device of claim 11 , wherein the active stylus emits a second signal and the touch sensor is configured to receive the second signal.

15. A device comprising:
a composite touch sensor comprising:
a capacitive touch sensor;
an interpolating force-sensitive resistor array touch sensor disposed adjacent to and coincident with the capacitive touch sensor, the interpolating force-sensitive resistor array t

Assignees

• Rosenberg Ilya D
• Beguin Julien G
• Amazon Tech Inc

Inventors

• Rosenberg Ilya D
• Beguin Julien G

Classifications

• G06F3/0412

  Digitisers structurally integrated in a display · CPC title

• G06F3/0414

  using force sensing means to determine a position · CPC title

• G06F3/044 Primary

  by capacitive means · CPC title

• G06F2203/04104

  Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger · CPC title

• G06F3/03545

  Pens or stylus · CPC title