# US 11,029,349 B2 · Capacitive sensing active electromagnetic emission cancellation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,029,349 B2 - Document ID: US11029349B2 - Status: Granted - Kind: B2 - Application number: 16/898,266 - Filed: 2020-06-10 - Published: 2020-09-24 - Granted: 2021-06-08 - Earliest claimed: 2016-12-22 - Assignees: Synaptics Incorporated - Applicants: Synaptics Incorporated - Inventors: Robert J. Bolender - Web page: https://patentgrep.com/patent/US11029349B2 ## CPC - G01R 27/2605: {Measuring capacitance (capacitive sensors G01D5/24)} - G06F 3/0446: {using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes} - G01R 27/2658: {Cavities, resonators, free space arrangements, reflexion or interference arrangements (G01R27/2647 takes precedence; optical methods G01R27/2682)} - 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)} - G06F 3/044: by capacitive means - G06F 2203/04112: Electrode mesh in capacitive digitiser: electrode for touch sensing is formed of a mesh of very fine, normally metallic, interconnected lines that are almost invisible to see. This provides a quite large but transparent electrode surface, without need for ITO or similar transparent conductive material - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract An input device is disclosed that provides reduced electromagnetic emissions while detecting the presence of an input object. In one embodiment, a first set of sensor electrodes is driven with a first modulated signal while a second set of sensor electrodes is driven with a second set of modulated signals that is based on an inverted first modulated signal. The first set of sensor electrodes may determine a capacitance value while the second set of sensor electrodes may reduce electromagnetic emissions associated with the first set of sensor electrodes. ## Claims ### Claim 1 A method of capacitive sensing using an array of sensor electrodes, comprising: driving, during a first time period, a first set of the sensor electrodes with a first modulated signal; generating a second modulated signal based at least in part on an inversion of the first modulated signal; driving, during the first time period, a second set of the sensor electrodes with the second modulated signal to reduce electromagnetic emissions associated with the first set of the sensor electrodes; driving, during a second time period, at least the second set of the sensor electrodes with the first modulated signal; driving, during the second time period, at least a first subset of the sensor electrodes in the first set with the second modulated signal; and determining, during the first time period, a first capacitance value associated with the first set of the sensor electrodes. ### Claim 2 (depends on 1) The method of claim 1 further comprising: determining a presence of an input object based at least in part on the first capacitance value. ### Claim 3 (depends on 1) The method of claim 1, wherein the first set of the sensor electrodes and the second set of the sensor electrodes are oriented along a common axis of the array. ### Claim 4 (depends on 1) The method of claim 1, wherein the first capacitance value is associated with an absolute capacitance measurement. ### Claim 5 (depends on 1) The method of claim 1, further comprising: driving, during the first time period, a third set of sensor electrodes with the first modulated signal, wherein the third set of sensor electrodes is disposed orthogonally with respect to the first set of the sensor electrodes. ### Claim 6 (depends on 1) The method of claim 1, wherein the first set of the sensor electrodes includes more sensor electrodes than the second set of the sensor electrodes, and wherein the second modulated signal is driven with a different amplitude than an amplitude of the first modulated signal. ### Claim 7 (depends on 1) The method of claim 1, wherein the second set of sensor electrodes include more sensor electrodes than the first set of sensor electrodes, and wherein the first modulated signal is driven with a different amplitude than an amplitude of the second modulated signal. ### Claim 8 (depends on 1) The method of claim 1, further comprising: driving, during the second time period, a second subset of the first set of the sensor electrodes, different than the first subset, with the first modulated signal. ### Claim 9 (depends on 8) The method of claim 8, further comprising: determining, during the second time period, a second capacitance value associated with the second set of the sensor electrodes and the second subset of the first set of the sensor electrodes; and determining a presence of an input object based at least in part on the second capacitance value. ### Claim 10 An input device comprising: an array of sensor electrodes comprising: a first set of sensor electrodes; and a second set of sensor electrodes; and a processing system configured to: drive, during a first time period, the first set of the sensor electrodes with a first modulated signal; generate a second modulated signal based at least in part on an inversion of the first modulated signal; drive, during the first time period, the second set of the sensor electrodes with the second modulated signal to reduce electromagnetic emissions associated with the first set of the sensor electrodes; drive, during a second time period, at least the second set of the sensor electrodes with the first modulated signal; drive, during the second time period, at least a first subset of the sensor electrodes in the first set with the second modulated signal; and determine, during the first time period, a first capacitance value associated with the first set of the sensor electrodes. ### Claim 11 (depends on 10) The input device of claim 10, wherein the processing system is further configured to: determine a presence of an input object based at least in part on the first capacitance value. ### Claim 12 (depends on 10) The input device of claim 10, wherein the first set of the sensor electrodes and the second set of the sensor electrodes are oriented along a common axis of the array. ### Claim 13 (depends on 10) The input device of claim 10, wherein the first capacitance value is associated with an absolute capacitance measurement. ### Claim 14 (depends on 10) The input device of claim 10, wherein the processing system is further configured to: drive, during the first time period, a third set of sensor electrodes with the first modulated signal, wherein the third set of sensor electrodes is disposed orthogonally with respect to the first set of the sensor electrodes. ### Claim 15 (depends on 10) The input device of claim 10, wherein the first set of the sensor electrodes includes more sensor electrode area than the second set of the sensor electrodes, and wherein the processing system is further configured to drive the second modulated signal with an amplitude greater than an amplitude of the first modulated signal. ### Claim 16 (depends on 10) The input device of claim 10, wherein the second set of the sensor electrodes includes more sensor electrode area than the first set of the sensor electrodes, and wherein the processing system is further configured to drive the first modulated signal with an amplitude greater than an amplitude of the second modulated signal. ### Claim 17 (depends on 10) The input device of claim 10, wherein the processing system is further configured to: drive, during the second time period, a second subset of the first set of the sensor electrodes, different than the first subset, with the first modulated signal; determine, during the second time period, a second capacitance value associated with the second set of the sensor electrodes and the second subset of the first set of the sensor electrodes; and determine a presence of an input object based at least in part on the second capacitance value. ### Claim 18 A processing system comprising: means for driving, during a first time period, a first set of sensor electrodes with a first modulated signal; means for generating a second modulated signal based at least in part on an inversion of the first modulated signal; means for driving, during the first time period, a second set of sensor electrodes with the second modulated signal to reduce electromagnetic emissions associated with the first set of the sensor electrodes; means for driving, during a second time period, at least the second set of the sensor electrodes with the first modulated signal; means for driving, during the second time period, at least a first subset of the sensor electrodes in the first set with the second modulated signal; and means for determining, during the first time period, a first capacitance value associated with the first set of the sensor electrodes. ### Claim 19 (depends on 18) The processing system of claim 18, further comprising: means for determining a presence of an input object based at least in part on the first capacitance value.