# US 10,372,271 B2 · Adjustment of touch sensing stimulation voltage levels based on touch performance > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,372,271 B2 - Document ID: US10372271B2 - Status: Granted - Kind: B2 - Application number: 14/335,551 - Filed: 2014-07-18 - Published: 2016-01-21 - Granted: 2019-08-06 - Earliest claimed: 2014-07-18 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: Jacob L. Matlick; Adam Geboff - Web page: https://patentgrep.com/patent/US10372271B2 ## CPC - G06F 1/3262: {Power saving in digitizer or tablet} - G06F 3/04162: {for exchanging data with external devices, e.g. smart pens, via the digitiser sensing hardware} - 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 3/04182: {Filtering of noise external to the device and not generated by digitiser components} - G06F 3/0442: {using active external devices, e.g. active pens, for transmitting changes in electrical potential to be received by the digitiser} - G06F 3/0445: {using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer} - G06F 3/0443: {using a single layer of sensing electrodes} - 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 The adjustment of stimulation signal amplitudes in capacitive touch sensor panels and/or styli to reduce power consumption while preserving satisfactory touch performance is disclosed, in particular in situations where the noise level is not significant and there is excess SNR margin. To accomplish this, one or more metrics can be measured, calculated or otherwise determined to use as a predictor of touch performance, and these metrics can be processed to determine the minimum stimulation voltage required to maintain acceptable touch performance. ## Claims ### Claim 1 A method of determining a stimulation voltage for a touch sensing system, comprising: capturing one or more touch sensor panel images over a particular time interval, each touch sensor panel image captured by stimulating electrodes of a touch sensor panel with a same first stimulation voltage, wherein the one or more touch sensor panel images indicate one or more detected touches; computing one or more metrics based on at least one touch sensor panel image that indicates at least one of the one or more detected touches; determining a second stimulation voltage amplitude from the one or more metrics; dynamically adjusting the stimulation voltage such that an amplitude of the adjusted stimulation voltage is equal to the second stimulation voltage-amplitude determined from the one or more metrics computed based on the at least one touch sensor panel image that indicates at least one of the one or more detected touches; and stimulating the touch sensor system with the adjusted stimulation voltage. ### Claim 2 (depends on 1) The method of claim 1, wherein determining the second stimulation voltage amplitude includes determining a difference between the computed one or more metrics and targeted one or more metrics. ### Claim 3 (depends on 1) The method of claim 1, further comprising: determining one or more touch locations of the one or more detected touches; and excluding the one or more touch locations from the one or more captured touch sensor panel images to generate one or more processed touch sensor panel images without the one or more detected touches. ### Claim 4 (depends on 3) The method of claim 3, wherein computing the one or more metrics comprises computing one or more of an average amplitude and variance of the one or more processed touch sensor panel images without the one or more detected touches. ### Claim 5 (depends on 3) The method of claim 3, further comprising: determining an actual full scale amplitude voltage swing of touch and no-touch sense signals received from the touch sensing system; and computing an actual signal-to-noise ratio (SNR) based on the one or more metrics and the actual full scale amplitude voltage swing. ### Claim 6 (depends on 5) The method of claim 5, further comprising: determining the second stimulation voltage amplitude from the actual SNR; applying the adjusted stimulation voltage to the touch sensing system to generate one or more revised captured touch sensor panel images; and calculating a revised actual SNR from the one or more revised captured touch sensor panel images. ### Claim 7 (depends on 1) The method of claim 1, further comprising: determining actual touch locations of the one or more detected touches from the one or more captured touch sensor panel images; and adding an ideal touch profile to the one or more captured touch sensor panel images at one or more predetermined ideal touch locations where no actual touch location has been determined to form one or more simulated touch images. ### Claim 8 (depends on 7) The method of claim 7, further comprising computing a plurality of simulated touch locations from the one or more simulated touch images. ### Claim 9 (depends on 8) The method of claim 8, wherein computing the one or more metrics comprises computing a simulated touch location jitter between the one or more ideal touch locations and the plurality of simulated touch locations. ### Claim 10 (depends on 9) The method of claim 9, further comprising: determining the second stimulation voltage amplitude from the computed simulated touch location jitter; applying the adjusted stimulation voltage to the touch sensing system to generate a one or more revised captured touch sensor panel images; and calculating a revised simulated touch location jitter from the one or more revised captured touch sensor panel images. ### Claim 11 (depends on 1) The method of claim 1, wherein computing the one or more metrics based on the at least one touch sensor panel image comprises computing the one or more metrics based on a plurality of touch sensor panel images, each of which indicates the one or more detected touches. ### Claim 12 A non-transitory computer-readable storage medium having stored therein instructions, which when executed by a device, cause the device to perform a method comprising: capturing one or more touch sensor panel images over a particular time interval, each touch sensor panel image captured by stimulating electrodes of a touch sensor panel with a same first stimulation voltage, wherein the one or more touch sensor panel images indicate one or more detected touches; computing one or more metrics based on at least one touch sensor panel image that indicates at least one of the one or more detected touches; determining second stimulation voltage amplitude from the one or more metrics; dynamically adjusting the stimulation voltage such that an amplitude of the adjusted stimulation voltage is equal to the second stimulation voltage-amplitude determined from the one or more metrics computed based on the at least one touch sensor panel image that indicates at least one of the one or more detected touches; and stimulating the touch sensor system with the adjusted stimulation voltage. ### Claim 13 (depends on 12) The non-transitory computer-readable storage medium of claim 12, wherein determining the second stimulation voltage amplitude includes determining a difference between the computed one or metrics and targeted one or more metrics. ### Claim 14 (depends on 12) The non-transitory computer-readable storage medium of claim 12, the method further comprising: determining one or more touch locations of the one or more detected touches; and excluding the one or more touch locations from the one or more captured touch sensor panel images to generate one or more processed touch sensor panel images without the one or more detected touches. ### Claim 15 (depends on 14) The non-transitory computer-readable storage medium of claim 14, the method further comprising: determining an actual full scale amplitude voltage swing of touch and no-touch sense signals received from the touch sensing system; and computing an actual signal-to-noise ratio (SNR) based on the one or more metrics and the actual full scale amplitude voltage swing. ### Claim 16 (depends on 12) The non-transitory computer-readable storage medium of claim 12, the method further comprising: determining actual touch locations of the one or more detected touches from the one or more captured touch sensor panel images; and adding an ideal touch profile to the one or more captured touch sensor panel images at one or more predetermined ideal touch locations where no actual touch location has been determined to form one or more simulated touch images. ### Claim 17 (depends on 16) The non-transitory computer-readable storage medium of claim 16, the method further comprising: computing a plurality of simulated touch locations from the one or more simulated touch images. ### Claim 18 (depends on 17) The non-transitory computer-readable storage medium of claim 17, the method further comprising: wherein computing the one or more metrics comprises computing a simulated touch location jitter between the one or more ideal touch locations and the plurality of simulated touch locations. ### Claim 19 (depends on 12) The non-transitory computer-readable storage medium of claim 12, wherein computing the one or more metrics based on the at least one touch sensor panel image comprises computing the one or more metrics based on a plurality of touch sensor panel images, each of which indicates the one or more detected touches. ### Claim 20 A computing device for determining a stimulation voltage for a touch sensing system, comprising: a touch sensor panel; and a touch controller communicatively coupled to the touch sensor panel, the touch controller including circuitry configured to stimulate the touch sensor panel and receive sense signals from the touch sensor panel, and a processor capable of capturing one or more touch sensor panel images over a particular time interval, each touch sensor panel image captured by stimulating electrodes of the touch sensor panel with a same first stimulation voltage, wherein the one or more touch sensor panel images indicate one or more detected touches; computing one or more metrics based on at least one touch sensor panel image that indicates at least one of the one or more detected touches; determining a second stimulation voltage amplitude from the one or more metrics; dynamically adjusting the stimulation voltage such that an amplitude of the adjusted stimulation voltage is equal to the second stimulation voltage-amplitude determined from the one or more metrics computed based on at least one touch sensor panel image that indicates at least one of the one or more detected touches; and stimulating the touch sensor system with the adjusted stimulation voltage. ### Claim 21 (depends on 20) The computing device of claim 20, wherein determining the second stimulation voltage amplitude includes determining a difference between the computed one or metrics and targeted one or more metrics. ### Claim 22 (depends on 20) The computing device of claim 20, the processor further capable of: determining one or more touch locations of the one or more detected touches; and excluding the one or more touch locations from the one or more captured touch sensor panel images to generate one or more processed touch sensor panel images without the one or more detected touches. ### Claim 23 (depends on 22) The computing device of claim 22, the processor further capable of: determining an actual full scale amplitude voltage swing of touch and no-touch sense signals received from the touch sensing system; and computing an actual signal-to-noise ratio (SNR) based on the one or more metrics and the actual full scale amplitude voltage swing. ### Claim 24 (depends on 20) The computing device of claim 20, the processor further capable of: determining actual touch locations of the one or more detected touches from the one or more captured touch sensor panel images; and adding an ideal touch profile to the one or more captured touch sensor panel images at one or more predetermined ideal touch locations where no actual touch location has been determined to form one or more simulated touch images. ### Claim 25 (depends on 24) The computing device of claim 24, the processor further capable of: computing a plurality of simulated touch locations from the one or more simulated touch images. ### Claim 26 (depends on 25) The computing device of claim 25, the processor further capable of: wherein computing the one or more metrics comprises computing a simulated touch location jitter between the one or more ideal touch locations and the plurality of simulated touch locations. ### Claim 27 (depends on 20) The computing device of claim 20, wherein computing the one or more metrics based on the at least one touch sensor panel image comprises computing the one or more metrics based on a plurality of touch sensor panel images, each of which indicates the one or more detected touches.