Granted Patent B2

US 12,723,932 · App. 18/273,470 · Granted Sep 1, 2026

Inventors: Constantinos Tsangarides (Cambridge, GB); Michael Astley (Cambridge, GB); Riccardo Micci (Cambridge, GB); Jiahao Li (Cambridge, GB)

Assignee: Cambridge Touch Technologies Ltd.

G01L1/16G06F3/04144H10N30/302

Abstract

Claims (55)

1 . A device comprising:

a piezoelectric sensor comprising a layer of piezoelectric material disposed between a plurality of sensing electrodes and at least one counter electrode; and

a controller connected to the piezoelectric sensor;

wherein the plurality of sensing electrodes are arranged to form one or more active regions, each active region of the one or more active regions comprising:

a group of one or more primary sensing electrodes of the plurality of sensing electrodes, the group of one or more primary sensing electrodes arranged with overlying indicia defined on a surface of the device so as to define one or more user input controls;

a group of one or more secondary sensing electrodes of the plurality of sensing electrodes, the group of one or more secondary sensing electrodes surrounding the group of one or more primary sensing electrodes, wherein the group of one or more secondary sensing electrodes do not correspond directly to user input controls, and wherein the group of one or more secondary sensing electrodes have no corresponding indicia defining user input controls; and

a perimeter, the perimeter being a locus of points separating the group of one or more primary sensing electrodes from the group of one or more secondary sensing electrodes, such that the group of one or more primary sensing electrodes are within the perimeter and the group of one or more secondary sensing electrodes are outside the perimeter;

wherein the controller is configured, for each active region of the one or more active regions, in response to receiving piezoelectric signals from the active region corresponding to an applied force:

to measure primary piezoelectric charges induced on each of the corresponding group of one or more primary sensing electrodes of the active region;

to measure secondary piezoelectric charges induced on each of the corresponding group of one or more secondary sensing electrodes of the active region; and

based on comparing the measured primary piezoelectric charges to the measured secondary piezoelectric charges, to determine whether a centroid of the applied force is within the perimeter of the active region;

wherein the controller is further configured, in response to determining at least one active region of the one or more active regions is being pressed with a corresponding applied force having a centroid determined to be within the perimeter of the at least one active region, to output user input data including details of which of the user input controls defined by the group of one or more primary sensing electrodes of the at least one active region have been actuated by the corresponding applied force.

2 . The device according to claim 1 , wherein the group of one or more secondary sensing electrodes of a first active region of the one or more active regions comprises:

first and second regions of conductive material disposed on opposite sides of the first active region along a first direction; and

third and fourth regions of conductive material disposed on opposite sides of the first active region along a second direction which is different to the first direction.

3 . The device according to claim 2 , wherein:

the first and second regions of conductive material are electrically connected together to provide a first secondary sensing electrode of the group of one or more secondary sensing electrodes.

4 . The device according to claim 2 wherein the first, second, third and fourth regions of conductive material are all electrically connected together to provide a first secondary sensing electrode of the one or more secondary sensing electrodes.

5 . The device according to claim 2 , wherein each of the first, second, third and fourth regions of conductive material provides a separate secondary sensing electrode of the group of one or more secondary sensing electrodes.

6 . The device according to claim 5 , wherein the controller is configured to sum piezoelectric charges from the first and second regions of conductive material to determine a first secondary piezoelectric charge corresponding to the first and second regions of conductive material.

7 . The device according to claim 1 , wherein the group of one or more secondary sensing electrodes of a first active region of the one or more active regions comprises one secondary sensing electrode of the one or more secondary sensing electrodes in the form of a region of conductive material extending around a majority of the perimeter of the first active region.

8 . The device according to claim 1 , wherein the piezoelectric sensor comprises a single counter electrode which is common to all of the plurality of sensing electrodes.

9 . The device according to claim 8 , wherein the single counter electrode is provided by a metal sheet forming at least part of a casing of the device, and wherein the layer of piezoelectric material is supported by the metal sheet.

10 . The device according to claim 1 , wherein the piezoelectric sensor comprises a separate counter electrode corresponding to each of the plurality of sensing electrodes.

11 . The device according to claim 1 , wherein all of the group of one or more secondary sensing electrodes of at least one active region of the one or more active regions are opposed across the layer of piezoelectric material by a common secondary counter electrode corresponding to the at least one active region.

12 . The device according to claim 11 , wherein each of the one or more primary sensing electrode of the group of one or more primary sensing electrodes of the at least one active region is opposed across the layer of piezoelectric material by a respective primary counter electrode.

13 . The device according to claim 11 , wherein all of the group of one or more primary sensing electrodes of the at least one active region are opposed across the layer of piezoelectric material by a common primary counter electrode corresponding to that active region.

14 . The device according to claim 11 , wherein the group of one or more primary sensing electrodes of the at least one active region are opposed across the layer of piezoelectric material by a number of primary counter electrodes which is different than the number of primary sensing electrodes belonging to the at least one active region.

15 . The device of claim 1 , wherein all of the secondary sensing electrodes are opposed across the layer of piezoelectric material by a single common secondary counter electrode.

16 . The device according to claim 1 , wherein for a given active region, the corresponding group of one or more primary sensing electrodes and the corresponding group of one or more secondary sensing electrodes are configured with relative areas and positions such that it is possible to define a threshold multiplier corresponding to each secondary sensing electrode of the given active region, wherein the threshold multipliers for the given active region satisfy:

in response to application of a force having a centroid within the perimeter of the given active region the secondary piezoelectric charge measured from each secondary sensing electrode of the corresponding group of one or more secondary sensing electrodes is less than a product of the respective threshold multiplier and a total primary piezoelectric charge measured from all of the corresponding group of one or more primary sensing electrodes; and

in response to application of a force having a centroid outside the perimeter of the given active region, a secondary piezoelectric charge measured from at least one secondary sensing electrode of the corresponding group of one or more secondary sensing electrodes is greater than the product of the respective threshold multiplier and the total primary piezoelectric charge measured from all of the primary sensing electrodes of the corresponding group of one or more primary sensing electrodes; and

wherein the controller is configured to store pre-calibrated threshold multipliers corresponding to each secondary sensing electrode, and for the given active region to determine whether an applied force has a centroid within the corresponding perimeter by comparing each secondary piezoelectric charge measured from a secondary sensing electrode belonging to the group of one or more secondary sensing electrodes of the given active region against a product of the respective threshold multiplier with a sum over the primary piezoelectric charges measured from the group of one or more primary sensing electrodes of the given active region.

17 . The device according to claim 1 , wherein the indicia overlying the group of one or more primary sensing electrodes of at least one active region of the one or more active region define one or more user input controls comprising at least one of one or more buttons, a slider control, a dial control, a swipe gesture control, a button pad or a touch pad.

18 . A device comprising:

a piezoelectric sensor comprising a layer of piezoelectric material disposed between a plurality of sensing electrodes and at least one counter electrode, wherein the plurality of sensing electrodes are arranged to form one or more active regions, each active region of the one or more active regions comprising:

a group of one or more primary sensing electrodes of the plurality of sensing electrodes, the group of one or more primary sensing electrodes arranged with overlying indicia defined on a surface of the device so as to define one or more user input controls;

a group of one or more secondary sensing electrodes of the plurality of sensing electrodes, the group of one or more secondary sensing electrodes surrounding the group of one or more primary sensing electrodes, wherein the group of one or more secondary sensing electrodes do not correspond directly to user input controls, and wherein the group of one or more secondary sensing electrodes have no corresponding indicia defining user input controls; and

a perimeter, the perimeter being a locus of points separating the group of one or more primary sensing electrodes from the group of one or more secondary sensing electrodes, such that the group of one or more primary sensing electrodes are within the perimeter and the group of one or more secondary sensing electrodes are outside the perimeter;

wherein the group of one or more secondary sensing electrodes of at least one active region of the one or more active regions comprise one secondary sensing electrode in the form of a region of conductive material extending around a majority of the perimeter of the at least one active region.

19 . A device comprising:

a piezoelectric sensor comprising a layer of piezoelectric material disposed between a plurality of sensing electrodes and at least one counter electrode; and

a controller connected to the piezoelectric sensor;

wherein the plurality of sensing electrodes are arranged to form one or more active regions, each active region of the one or more active regions comprising:

a group of one or more primary sensing electrodes of the plurality of sensing electrodes, the group of one or more primary sensing electrodes arranged with overlying indicia defined on a surface of the device so as to define one or more user input controls;

a group of one or more secondary sensing electrodes of the plurality of sensing electrodes, the group of one or more secondary sensing electrodes bracketing the group of one or more primary sensing electrodes, wherein the group of one or more secondary sensing electrodes do not correspond directly to user input controls, and wherein the group of one or more secondary sensing electrodes have no corresponding indicia defining user input controls; and

a perimeter, the perimeter being a locus of points separating the group of one or more primary sensing electrodes from the group of one or more secondary sensing electrodes, such that the group of one or more primary sensing electrodes are within the perimeter and the group of one or more secondary sensing electrodes are outside the perimeter;

wherein the controller is configured, for each active region of the one or more active regions, in response to receiving piezoelectric signals from the active region corresponding to an applied force:

to measure primary piezoelectric charges induced on each of the corresponding group of one or more primary sensing electrodes of the active region;

to measure secondary piezoelectric charges induced on each of the corresponding group of one or more secondary sensing electrodes of the active region; and

based on comparing the measured primary piezoelectric charges to the measured secondary piezoelectric charges, to determine whether a centroid of the applied force is within the perimeter of the active region;

wherein the controller is further configured, in response to determining at least one active region of the one or more active regions is being pressed with a corresponding applied force having a centroid determined to be within the perimeter of the at least one active region, to output user input data including details of which of the user input controls defined by the group of one or more primary sensing electrodes of the at least one active region have been actuated by the corresponding applied force.

20 . The device according to claim 19 , wherein the group of one or more primary sensing electrodes of a first active region of the one or more active regions comprises:

an array of primary sensing electrodes of the group of one or more primary sensing electrodes spaced apart along a path; and

wherein the group of one or more secondary sensing electrodes of the first active region comprises a pair of secondary sensing electrodes of the group of one or more secondary sensing electrodes arranged on the path at either end of the array of primary sensing electrodes.

Assignments (1)

Priority Claims (1)

Continuity (1)

References Cited (73)