# US 10,503,329 B2 · Capacitive sensing apparatus and methods > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,503,329 B2 - Document ID: US10503329B2 - Status: Granted - Kind: B2 - Application number: 15/578,268 - Filed: 2016-06-30 - Published: 2018-06-07 - Granted: 2019-12-10 - Earliest claimed: 2015-07-27 - Assignees: TouchNetix Limited - Applicants: TouchNetix Limited - Inventors: Peter Timothy Sleeman; Stephen William Roberts; Christopher Kyle Ard - Web page: https://patentgrep.com/patent/US10503329B2 ## CPC - G01D 5/241: by relative movement of capacitor electrodes - G01D 5/2417: {by varying separation} - G06F 3/0416: {Control or interface arrangements specially adapted for digitisers} - G06F 3/0445: {using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer} - G06F 3/0447: {Position sensing using the local deformation of sensor cells} - H03H 3/08: for the manufacture of resonators or networks using surface acoustic waves - H03K 17/975: using a capacitive movable element - G06F 3/04142: {the force sensing means being located peripherally, e.g. disposed at the corners or at the side of a touch sensing plate} - G06F 2203/04101: 2.5D-digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface and also measures the distance of the input means within a short range in the Z direction, possibly with a separate measurement setup - G06F 2203/04105: Pressure sensors for measuring the pressure or force exerted on the touch surface without providing the touch position - G01D: MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P) - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) ## Abstract A capacitive sensor comprising: a first electrode; a displacement element moveably mounted relative to the first electrode; and a second electrode coupled to the displacement element so that displacement of the displacement element along a displacement direction changes a separation between the first electrode and the second electrode; and a controller element configured to selectively operate in a displacement sensing mode and in a proximity sensing mode, wherein in the displacement sensing mode, the controller element is configured to electrically couple the second electrode to a reference potential and to electrically couple the first electrode to capacitance measurement circuitry to measure a capacitance characteristic of the first electrode to determine a displacement of the displacement element relative to the reference electrode; and in the proximity sensing mode, the controller element is configured to electrically couple the second electrode to capacitance measurement circuitry to measure a capacitance characteristic associated with the second electrode to detect the presence of an object in proximity to the second electrode; and in the displacement sensing mode, the controller element is configured to electrically couple the second electrode to a reference potential signal. ## Claims ### Claim 1 A capacitive sensor comprising: a first electrode; a displacement element moveably mounted relative to the first electrode; and a second electrode coupled to the displacement element so that displacement of the displacement element along a displacement direction changes a separation between the first electrode and the second electrode; and a controller element configured to selectively operate in a displacement sensing mode and in a proximity sensing mode, wherein in the proximity sensing mode, the controller element is configured to electrically couple the second electrode to capacitance measurement circuitry to measure a capacitance characteristic associated with the second electrode to detect the presence of an object in proximity to the second electrode; and in the displacement sensing mode, the controller element is configured to electrically couple the second electrode to a reference potential signal, wherein the controller element is further configured when operating in the proximity sensing mode to electrically couple the first electrode to a time varying drive signal corresponding to a time varying drive signal applied to the second electrode by the capacitance measurement circuitry. ### Claim 2 (depends on 1) The capacitive sensor of claim 1, wherein the controller element is further configured in the displacement sensing mode to electrically couple the first electrode to capacitance measurement circuitry to measure a capacitance characteristic associated with the first electrode to determine a displacement of the displacement element relative to the reference electrode. ### Claim 3 (depends on 1) The capacitive sensor of claim 1, wherein the controller element is further configured in the displacement sensing mode to electrically couple a further electrode which is mounted to the displacement element and capacitively coupled to the reference electrode to capacitance measurement circuitry to measure a capacitance characteristic associated with the further electrode to determine a displacement of the displacement element relative to the reference electrode. ### Claim 4 (depends on 1) The capacitive sensor of claim 1, wherein the controller element is further configured when operating in the proximity sensing mode to electrically decouple the first electrode from the capacitance measurement circuitry so it is electrically floating. ### Claim 5 (depends on 2) The capacitive sensor of claim 2, wherein a gain of the capacitance measurement circuitry for measuring the capacitance characteristic in the displacement sensing mode is different from a gain of the capacitance measurement circuitry for measuring the capacitance characteristic associated with the second electrode in the proximity sensing mode. ### Claim 6 (depends on 1) The capacitive sensor of claim 1, wherein the first electrode comprises a first conductive trace mounted to a frame element. ### Claim 7 (depends on 1) The capacitive sensor of claim 1, wherein the second electrode comprises a second conductive trace mounted to the displacement element. ### Claim 8 (depends on 1) The capacitive sensor of claim 1, wherein the second electrode comprises a deformable electrode arranged between the displacement element and the first electrode, wherein the deformable electrode has a contact surface facing the first electrode and insulated therefrom by an insulator layer, and wherein at least part of the contact surface is inclined relative to an opposing surface of the first electrode such that when the deformable electrode is compressed along the displacement direction by a displacement of the displacement element relative to the first electrode there is a reduction in separation between the contact surface and the opposing surface of the first electrode. ### Claim 9 (depends on 8) The capacitive sensor of claim 8, wherein the inclination of the at least part of the contact surface relative to the opposing surface of the first electrode is provided by virtue of at least a portion of one of the contact surface and the opposing surface comprising a curved surface. ### Claim 10 (depends on 8) The capacitive sensor of claim 8, wherein the deformable electrode comprises a conductive foam material and/or a conductive rubber material and/or a conductive plastics material and/or a sprung metallic material and/or a flexible conductive sheath surrounding a deformable core. ### Claim 11 (depends on 1) The capacitive sensor of claim 1, wherein the displacement element is movably mounted relative to the first electrode using a resiliently compressible support element. ### Claim 12 (depends on 1) The capacitive sensor of claim 1, wherein a capacitance characteristic measured by the capacitance measurement circuitry in the displacement sensing mode is a self-capacitance of the first electrode or a further electrode mounted to the displacement element and capacitively coupled to the first electrode. ### Claim 13 (depends on 1) The capacitive sensor of claim 1, wherein the capacitance characteristic measured by the capacitance measurement circuitry in the proximity sensing mode is a self-capacitance of the second electrode. ### Claim 14 (depends on 1) The capacitive sensor of claim 1, wherein the controller element is configured when in the displacement sensing mode to generate a displacement output signal to indicate when the controller element determines there has been a displacement of the displacement element relative to the first electrode. ### Claim 15 (depends on 1) The capacitive sensor of claim 1, wherein the controller element is configured when in the displacement sensing mode to determine there has been a displacement of the displacement element relative to the first electrode by comparing a difference between two measurements of a capacitance characteristic associated with the first electrode or a further electrode mounted to the displacement element and capacitively coupled to the first electrode with a displacement trigger threshold. ### Claim 16 (depends on 1) The capacitive sensor of claim 1, wherein the controller element is configured when in the proximity sensing mode to generate a proximity output signal to indicate when the controller element determines there is an object in proximity to the second electrode. ### Claim 17 (depends on 1) The capacitive sensor of claim 1, wherein the controller element is configured when in the proximity sensing mode to determine there is an object in proximity to the second electrode by comparing a difference between two measurements of the capacitance characteristic associated with the second electrode with a proximity trigger threshold. ### Claim 18 (depends on 1) The capacitive sensor of claim 1, wherein the first electrode and the second electrode are aligned with a path running around at least a part of a peripheral region of the displacement element. ### Claim 19 (depends on 1) The capacitive sensor of claim 1, wherein the first electrode comprises a plurality of first electrode portions, and wherein when in the displacement sensing mode, the controller element is configured to electrically couple the respective first electrode portions to capacitance measurement circuitry to separately measure a capacitance characteristic for respective ones of the first electrode portions or corresponding further electrode portions mounted to the displacement element and capacitively coupled to the respective first electrode portions to determine displacements of the displacement element relative to respective ones of the first electrode portions. ### Claim 20 (depends on 19) The capacitive sensor of claim 19, wherein the controller element is further configured to estimate a location of a displacement force applied to the displacement element from a comparison of the capacitance characteristics measured for respective ones of the first electrode portions. ### Claim 21 (depends on 1) The capacitive sensor of claim 1, wherein the second electrode comprises a plurality of second electrode portions, and wherein when in the proximity sensing mode, the controller element is configured to electrically couple the respective second electrode portions to the capacitance measurement circuitry to separately measure the capacitance characteristic for respective ones of the second electrode portions to detect the presence of an object in proximity to respective ones of the second electrode portions. ### Claim 22 (depends on 21) The capacitive sensor of claim 21, wherein the controller element is further configured to estimate a location of an object in proximity to the second electrode from a comparison of the capacitance characteristics measured for respective ones of the second electrode portions. ### Claim 23 (depends on 22) The capacitive sensor of claim 22, wherein the controller element is further configured to estimate a gesture made by an object in proximity to the second electrode from changes in a sequence of estimate a locations for the object. ### Claim 24 (depends on 1) The capacitive sensor of claim 1, wherein the controller element is configured to alternate between the proximity sensing mode and the displacement sensing mode in accordance with a predefined schedule. ### Claim 25 (depends on 1) The capacitive sensor of claim 1, wherein on detection of a displacement, the controller element is configured to remain in the displacement sensing mode until it is determined there is longer a displacement. ### Claim 26 (depends on 1) An apparatus comprising the capacitive sensor of claim 1. ### Claim 27 (depends on 26) The apparatus of claim 26, wherein the apparatus comprises further circuitry configured to be electrically isolated from the capacitance measurement circuitry of the capacitive sensor. ### Claim 28 (depends on 27) The apparatus of claim 27, wherein the further circuitry is configured to electrically float relative to the capacitance measurement circuitry when the further circuitry is electrically isolated from the capacitance measurement circuitry. ### Claim 29 (depends on 27) The apparatus of claim 27, wherein the further circuitry is electrically coupled to a time varying drive signal corresponding to a time varying drive signal used by the capacitance measurement circuitry for measuring the capacitance characteristic. ### Claim 30 A method of capacitive sensing comprising: providing a capacitive senor comprising a first electrode; a displacement element moveably mounted relative to the first electrode; and a second electrode coupled to the displacement element so that displacement of the displacement element along a displacement direction changes a separation between the first electrode and the second electrode; and selectively operating in one of a displacement sensing mode and a proximity sensing mode, wherein in the proximity sensing mode, the second electrode is electrically coupled to capacitance measurement circuitry to measure a capacitance characteristic associated with the second electrode to detect the presence of an object in proximity to the second electrode; and in the displacement sensing mode, the second electrode is electrically coupled to a reference potential signal, and wherein when in the proximity sensing mode, the first electrode is electrically coupled to a time varying drive signal corresponding to a time varying drive signal applied to the second electrode by the capacitance measurement circuitry. ### Claim 31 A capacitive sensor comprising: a first electrode; a displacement element moveably mounted relative to the first electrode; and a second electrode coupled to the displacement element so that displacement of the displacement element along a displacement direction changes a separation between the first electrode and the second electrode; and a controller element configured to selectively operate in a displacement sensing mode and in a proximity sensing mode, wherein in the proximity sensing mode, the controller element is configured to electrically couple the second electrode to capacitance measurement circuitry to measure a capacitance characteristic associated with the second electrode to detect the presence of an object in proximity to the second electrode; and in the displacement sensing mode, the controller element is configured to electrically couple the second electrode to a reference potential signal, and wherein the second electrode comprises a deformable electrode arranged between the displacement element and the first electrode, wherein the deformable electrode has a contact surface facing the first electrode and insulated therefrom by an insulator layer, and wherein at least part of the contact surface is inclined relative to an opposing surface of the first electrode such that when the deformable electrode is compressed along the displacement direction by a displacement of the displacement element relative to the first electrode there is a reduction in separation between the contact surface and the opposing surface of the first electrode.