# US 10,503,326 B2 · Display noise compensation in touch screen display using capacitive dividers > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,503,326 B2 - Document ID: US10503326B2 - Status: Granted - Kind: B2 - Application number: 15/247,106 - Filed: 2016-08-25 - Published: 2018-03-01 - Granted: 2019-12-10 - Earliest claimed: 2016-08-25 - Assignees: STMicroelectronics Asia Pacific Pte Ltd - Applicants: STMicroelectronics Asia Pacific Pte Ltd - Inventors: Leonard Liviu Dinu; Chee Weng Cheong; Eng Jye Ng - Web page: https://patentgrep.com/patent/US10503326B2 ## CPC - G06F 3/04184: {Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally} - G06F 3/0445: {using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer} - G06F 3/0446: {using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes} - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract An electronic device disclosed herein includes a display layer generating display noise based on scanning thereof, and a sensing layer including a plurality of sense lines. A common voltage layer is coupled to the display layer and the sensing layer, with the common voltage layer capacitively coupling the display noise from the display layer to the each of the plurality of sense lines of the sensing layer via a different parasitic impedance. An amplitude of the display noise seen at an input to each sense line is a function of a location of that sense line. The electronic device includes a plurality of compensation impedances, with each compensation impedance coupled to a different one of the plurality of sense lines. Each of the plurality of compensation impedances has an impedance value such that an amplitude of the display noise at an output of each sense line is substantially equal. ## Claims ### Claim 1 An electronic device, comprising: a display layer generating display noise based on scanning thereof; a sensing layer including a plurality of sense lines; a common voltage layer coupled to the display layer and the sensing layer, the common voltage layer capacitively coupling the display noise from the display layer to the each of the plurality of sense lines of the sensing layer via a different parasitic impedance; and a plurality of compensation impedances equal in number to the plurality of sense lines, each compensation impedance being, and remaining, directly electrically connected between a different one of the plurality of sense lines and ground in an unbroken fashion during operation of the electronic device such that each compensation impedance is directly electrically connected between one of the plurality of sense lines and ground in an unbroken fashion during operation of the electronic device, and such that each sense line is directly electrically connected to one of the compensation impedances in an unbroken fashion during operation of the electronic device, wherein each compensation impedance of the plurality of compensation impedances has an impedance value such that an amplitude of the display noise at an output of each sense line is substantially equal. ### Claim 2 (depends on 1) The electronic device of claim 1, wherein amplitudes of the display noise seen at inputs to at least some of the sense lines are not substantially equal. ### Claim 3 (depends on 1) The electronic device of claim 1, wherein an amplitude of the display noise seen at an input to each sense line is a function of a location of that sense line. ### Claim 4 (depends on 1) The electronic device of claim 1, wherein each of the plurality of compensation impedances forms an impedance divider with the parasitic impedance of its respective sense line. ### Claim 5 (depends on 1) The electronic device of claim 1, wherein the common voltage layer is driven at a plurality of connection points; and wherein an amplitude of the display noise seen at an input to each sense line is a function of the location of that sense line with respect to the plurality of connection points. ### Claim 6 (depends on 5) The electronic device of claim 5, wherein the amplitude of the display noise seen at the input to each sense line is a function of a distance of that sense line from the plurality of connection points, where the amplitude of the display noise seen at the input to sense lines closer to the plurality of connection points is less than the amplitude of the display noise seen at the input to sense lines farther from the plurality of connection points. ### Claim 7 (depends on 5) The electronic device of claim 5, wherein compensation impedances coupled to sense lines closer to the plurality of connection points are lesser in impedance value than compensation impedances coupled to sense lines farther from the plurality of connection points. ### Claim 8 (depends on 1) The electronic device of claim 1, wherein each compensation impedance comprises a compensation capacitor coupled between the output of its associated sense line and ground; wherein each impedance value is a capacitance value; wherein each parasitic impedance comprises a parasitic capacitance; and wherein the parasitic capacitance and compensation impedance for each sense line forms a capacitive divider. ### Claim 9 (depends on 1) The electronic device of claim 1, further comprising a sense circuit coupled to the plurality of sense lines and configured to process output from each of the plurality of sense lines, and to output a sense signal for each sense line. ### Claim 10 (depends on 9) The electronic device of claim 9, further comprising a digital circuit configured to program the capacitance value of each programmable value capacitor as a function of the sense signal for the sense line associated with each said programmable value capacitor. ### Claim 11 (depends on 9) The electronic device of claim 9, wherein the sense circuit processes the output from each of the plurality of sense lines by rejecting the display noise from the sense signal output for each sense line. ### Claim 12 (depends on 9) The electronic device of claim 9, wherein the sense circuit rejects the display noise by performing differential sensing of the plurality of sense lines. ### Claim 13 (depends on 1) The electronic device of claim 1, wherein each compensation impedance comprises a fixed value capacitor; and wherein each impedance value is a capacitance value. ### Claim 14 (depends on 1) The electronic device of claim 1, wherein each compensation impedance comprises a programmable value capacitor; and wherein each impedance value is a capacitance value. ### Claim 15 A method of operating a touch sensing device having a display layer, a common voltage layer, and a sensing layer, the method comprising: generating display noise by scanning the display layer; capacitively coupling the display noise from the display layer to the common voltage layer via at least one parasitic impedance; capacitively coupling the display noise from the common voltage layer to the each of a plurality of sense lines in the sensing layer via a different parasitic impedance; and compensating for different amplitudes of the display noise and for the different parasitic impedances by directly electrically connecting each compensation impedance of a plurality of compensation impedances equal in number to the plurality of sense lines between a different one of the plurality of sense lines and ground in an unbroken fashion during operation of the touch sensing device and such that each sense line is directly electrically connected to one of the plurality of compensation impedances in an unbroken fashion during operation of the touch sensing device, wherein each of the compensation impedances has an impedance value such that an amplitude of the display noise at an output of each sense line is substantially equal. ### Claim 16 (depends on 15) The method of claim 15, further comprising driving the common voltage layer at a plurality of connection points, such that an amplitude of the display noise seen at an input to each sense line is a function of the location of that sense line with respect to the plurality of connection points. ### Claim 17 (depends on 16) The method of claim 16, wherein the driving of the common voltage layer at the plurality of connection points results in the amplitude of the display noise seen at the input to each sense line being a function of a distance of that sense line from the plurality of connection points, such that the amplitude of the display noise see at the input to sense lines closer to the plurality of connection points is less than the amplitude of the display noise seen at the input to sense lines farther from the plurality of connection points. ### Claim 18 (depends on 17) The method of claim 17, wherein the compensation impedances coupled to sense lines closer to the plurality of connection points are lesser in value than compensation impedances coupled to sense lines farther from the plurality of connection points. ### Claim 19 (depends on 15) The method of claim 15, further comprising processing output from each of the plurality of sense lines and outputting a sense signal for each sense line. ### Claim 20 (depends on 19) The method of claim 19, wherein processing the output from each of the plurality of sense lines comprises rejecting the display noise from the sense signal output for each sense line. ### Claim 21 (depends on 20) The method of claim 20, wherein the display noise is rejected by performing differential sensing of the plurality of sense lines. ### Claim 22 An electronic device, comprising: a display layer generating display noise based on scanning thereof; a sensing layer including a plurality of sense lines; a common voltage layer coupled to the display layer and the sensing layer, the common voltage layer capacitively coupling the display noise from the display layer to the each of the plurality of sense lines of the sensing layer via a different parasitic impedance; and a plurality of compensation impedances, each compensation impedance being directly electrically connected to a different one of the plurality of sense lines in an unbroken fashion during operation of the electronic device, wherein each of the plurality of compensation impedances has an impedance value such that an amplitude of the display noise at an output of each sense line is substantially equal; wherein the plurality of compensation impedances and the plurality of sense lines are equal in number. ### Claim 23 (depends on 22) The electronic device of claim 22, wherein the common voltage layer is driven at a plurality of connection points; and wherein an amplitude of the display noise seen at an input to each sense line is a function of the location of that sense line with respect to the plurality of connection points. ### Claim 24 (depends on 23) The electronic device of claim 23, wherein compensation impedances coupled to sense lines closer to the plurality of connection points are lesser in value than compensation impedances coupled to sense lines farther from the plurality of connection points. ### Claim 25 (depends on 22) The electronic device of claim 22, wherein each compensation impedance comprises a fixed value capacitor; and wherein each impedance value is a capacitance value. ### Claim 26 (depends on 22) The electronic device of claim 22, wherein each compensation impedance comprises a programmable value capacitor; and wherein each impedance value is a capacitance value.