# US 2017/0255293 A1 · Force sensing using capacitive touch surfaces > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0255293 A1 - Document ID: US20170255293A1 - Status: Published application - Kind: A1 - Application number: 15/058,584 - Filed: 2016-03-02 - Published: 2017-09-07 - Earliest claimed: 2016-03-02 - Assignees: Google Inc. - Applicants: Google Inc. - Inventors: Kishore SUNDARA-RAJAN - Web page: https://patentgrep.com/patent/US20170255293A1 ## CPC - G06F 3/0447: {Position sensing using the local deformation of sensor cells} - G06F 3/04186: {Touch location disambiguation} - G06F 3/0445: {using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer} - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract In one general aspect, a method can include identifying contact with a surface of a touch-sensitive input device, identifying a location of the contact on the surface of the touch-sensitive input device, and calculating a change in a mutual capacitance between a first electrode and a second electrode included in a sensor module disposed below the surface of the touch-sensitive input device. The first electrode can be adjacent to the second electrode. The first electrode and the second electrode can be located approximate to the identified location of the contact on the surface of the touch-sensitive input device. The method can include estimating a contact-coupled capacitance based on the calculated change in a mutual capacitance between the first electrode and the second electrode, and calculating a force applied to the surface of the touch-sensitive input device at the identified location. ## Claims ### Claim 1 A method comprising: identifying, by a computing device, contact with a surface of a touch-sensitive input device; identifying, by the computing device, a location of the contact on the surface of the touch-sensitive input device; calculating a change in a mutual capacitance between a first electrode and a second electrode included in a sensor module disposed below the surface of the touch-sensitive input device, the first electrode being adjacent to the second electrode, the first electrode and the second electrode located approximate to the identified location of the contact on the surface of the touch-sensitive input device; estimating a contact-coupled capacitance based on the calculated change in a mutual capacitance between the first electrode and the second electrode; and calculating a force applied to the surface of the touch-sensitive input device at the identified location based on a change in self-capacitance of the first electrode and the second electrode and based on the estimated contact-coupled capacitance. ### Claim 2 (depends on 1) The method of claim 1, further comprising: calculating a change in a mutual capacitance between a third electrode and the second electrode included in the sensor module, the third electrode being adjacent to the second electrode and located closer to the identified location of the contact on the surface of the touch-sensitive input device than the first electrode; wherein estimating a contact-coupled capacitance is further based on the calculated change in a mutual capacitance between the third electrode and the second electrode; and wherein calculating the applied force is further based on a change in self-capacitance of the third electrode. ### Claim 3 (depends on 1) The method of claim 1, wherein the touch-sensitive input device is a touchpad. ### Claim 4 (depends on 1) The method of claim 1, wherein the touch-sensitive input device is a touchscreen. ### Claim 5 (depends on 4) The method of claim 4, wherein the surface of the touch-sensitive input device is a surface of a cover glass. ### Claim 6 (depends on 1) The method of claim 1, further comprising: providing the calculated applied force to an application executing on the computing device. ### Claim 7 (depends on 6) The method of claim 6, further comprising: controlling a function of the application based on a value of the calculated applied force. ### Claim 8 (depends on 1) The method of claim 1, wherein the identified contact with the surface of the touch-sensitive input device is provided by a finger of a user of the computing device contacting the surface of the touch-sensitive input device at the identified location. ### Claim 9 (depends on 1) The method of claim 1, wherein the identified contact with the surface of the touch-sensitive input device is provided by a stylus contacting the surface of the touch-sensitive input device at the identified location. ### Claim 10 A touch-sensitive input device comprising: a glass-plus-sensor module including: a cover glass including a top surface and a bottom surface; and at least two electrodes attached to the bottom surface of the cover glass, the at least two electrodes having an associated self-capacitance; an optically clear adhesive layer (OCA) layer; a display device having a top surface and a bottom surface; and a ground plane attached to the bottom surface of the display device; the OCA layer attaching the bottom surface of the cover glass to the top surface of the display device; and the glass-plus-sensor module bending towards the display device at a point of contact of a conductive element with the top surface of the cover glass, the bending changing, for each of the at least two electrodes, the self-capacitance associated with the electrode, and a calculation of a force applied by the contact of the conductive element with the top surface of the cover glass being based on the change in self-capacitance for each electrode. ### Claim 11 (depends on 10) The touch-sensitive input device of claim 10, wherein the OCA layer has a thickness; and wherein the calculation of a force applied by the contact of the conductive element with the top surface of the cover glass is further based on the thickness of the OCA layer. ### Claim 12 (depends on 10) The touch-sensitive input device of claim 10, wherein the self-capacitance associated with the electrode is a capacitance as measured between the electrode and the ground plane. ### Claim 13 (depends on 10) The touch-sensitive input device of claim 10, wherein the at least two electrodes are adjacent to one another; and wherein the calculation of a force applied by the contact of the conductive element with the top surface of the cover glass is further based on a mutual capacitance between the at least two electrodes. ### Claim 14 (depends on 10) The touch-sensitive input device of claim 10, wherein the conductive element is one of a finger of a user and a stylist. ### Claim 15 A computing device comprising: at least one controller; and a touch-sensitive input device configured to facilitate interaction by a user with a graphical user interface (GUI), the touch-sensitive input device comprising: a glass-plus-sensor module including: a cover glass including a top surface and a bottom surface; and at least two electrodes attached to the bottom surface of the cover glass, the at least two electrodes having an associated self-capacitance; a display device having a top surface and a bottom surface, the computing device being configured to render the GUI on the display device; an optically clear adhesive layer (OCA) layer attaching the bottom surface of the cover glass to the top surface of the display device; and a ground plane attached to the bottom surface of the display device, wherein the at least one controller and the touch-sensitive input device are collectively configured to: detect contact of a conductive element with the top surface of the cover glass, and based on the detected contact; determine, for each of the at least two electrodes, a self-capacitance associated with the electrode; and calculate a force applied by the contact of the conductive element with the top surface of the cover glass based on the determined self-capacitance associated with each of the at least two electrodes. ### Claim 16 (depends on 15) The computing device of claim 15, wherein the at least one controller is configured to: execute an application on the computing device; and provide the calculated applied force as input to the application. ### Claim 17 (depends on 15) The computing device of claim 15, wherein the conductive element is one of a finger of a user and a stylist. ### Claim 18 (depends on 15) The computing device of claim 15, wherein the self-capacitance associated with the electrode is a capacitance as measured between the electrode and the ground plane. ### Claim 19 (depends on 15) The computing device of claim 15, wherein the at least one controller and the touch-sensitive input device are collectively configured to determine, for each of the at least two electrodes, a mutual capacitance between the at least two electrodes. ### Claim 20 (depends on 19) The computing device of claim 19, wherein calculating a force applied by the contact of the conductive element with the top surface of the cover glass is further based on the determined mutual capacitance between the at least two electrodes.