# US 10,502,643 B2 · Resistive-capacitive deformation sensor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,502,643 B2 - Document ID: US10502643B2 - Status: Granted - Kind: B2 - Application number: 16/055,376 - Filed: 2018-08-06 - Published: 2018-12-27 - Granted: 2019-12-10 - Earliest claimed: 2015-09-02 - Assignees: Facebook Technologies, LLC - Applicants: Facebook Technologies, LLC - Inventors: Sean Jason Keller; Tristan Thomas Trutna; David R. Perek; Bruce A. Cleary, III - Web page: https://patentgrep.com/patent/US10502643B2 ## CPC - G01L 1/142: {using capacitors} - G01B 7/18: {using change in resistance} - G01B 7/22: {using change in capacitance} - G01L 1/22: using resistance strain gauges - G01L 5/165: using variations in capacitance - G01L: MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE (weighing G01G) - G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS ## Abstract A deformation sensing apparatus comprises an elastic substrate, a first strain-gauge element formed on a first surface of the elastic substrate, and configured to output a first signal in response to a strain applied in a first direction, and a second strain-gauge element formed on a second surface of the elastic substrate opposite to the first surface, and configured to output a second signal in response to a strain applied in the same first direction. ## Claims ### Claim 1 A deformation sensing apparatus comprising: a substrate; a first strain-gauge element coupled to a first portion of the substrate, and configured to output a first signal in response to a strain applied in a first direction; and a second strain-gauge element coupled to a second portion of the substrate distinct from the first portion, and configured to output a second signal in response to a strain applied in the same first direction, and wherein the deformation sensing apparatus is further configured to output a third signal responsive to an applied deformation, the third signal being measureable between a terminal of the first strain-gauge element and a terminal of the second strain gauge-element. ### Claim 2 (depends on 1) The deformation sensing apparatus of claim 1, wherein the first portion of the substrate is opposite to the second portion of the substrate. ### Claim 3 (depends on 1) The deformation sensing apparatus of claim 1, wherein the first portion of the substrate is a top portion of the substrate and the second portion of the substrate is a bottom portion of the substrate. ### Claim 4 (depends on 1) The deformation sensing apparatus of claim 1, wherein: the first strain-gauge element has two distinct terminals, a first terminal and a second terminal; the first signal is measurable across the first and second terminals of the first strain-gauge element; the second strain-gauge element has two distinct terminals, a third terminal and a fourth terminal; and the second signal is measurable across the third and fourth terminals of the second strain-gauge element. ### Claim 5 (depends on 1) The deformation sensing apparatus of claim 1, wherein the substrate comprises a flexible, electrically-insulating dielectric material. ### Claim 6 (depends on 5) The deformation sensing apparatus of claim 5, wherein: each of the first and second strain-gauge elements has a horse-shoe shape comprising an arcuate head and a pair of elongate leads extending from ends of the arcuate head; alignment of the shapes of the first and second strain-gauge elements correspond along an axis orthogonal to the first portion and the second portion of the substrate; central axes of the first and second strain-gauge elements are aligned parallel and coplanar to each other along a planes orthogonal to the first portion and the second portion of the substrate; and corresponding leads of the pairs of elongate leads of the first and second strain-gauge elements are respectively length-wise parallel and have substantially the same dimensions. ### Claim 7 (depends on 6) The deformation sensing apparatus of claim 6, wherein: a measurement circuit configured to measure the first signal from the first strain-gauge element and the second signal from the second strain-gauge element in response to an applied deformation; and a deformation analyzer configured to compute a measure of stretch deformation and a measure of flex deformation of the sensing apparatus, in the applied deformation, based on the measured first signal from the first strain-gauge element, the measured second signal of the second strain-gauge element, and the third signal. ### Claim 8 (depends on 7) The deformation sensing apparatus of claim 7, wherein: the measure of stretch deformation is indicative of an average change in lengths in relationship to an undeformed length of the first and second strain gauge elements; and the measure of flex deformation is indicative of a bend radius of an angular bend of portions of the substrate on which the first and second strain-gauge elements are formed. ### Claim 9 (depends on 7) The deformation sensing apparatus of claim 7, wherein the deformation analyzer is further configured to determine whether the stretch deformation corresponds to a compression stretch or an elongation stretch, by comparing the measured first, second, and third signals, based on a sign of changes in resistances of the first and second strain gauge elements and a sign of change in capacitance of the substrate. ### Claim 10 (depends on 1) The deformation sensing apparatus of claim 1, further comprising: a measurement circuit configured to measure the first signal from the first strain-gauge element and the second signal from the second strain-gauge element in response to the applied deformation; and a deformation analyzer configured to compute a measure of stretch deformation and a measure of flex deformation of the sensing apparatus, in the applied deformation, based on the measured first signal from the first strain-gauge element, the measured second signal of the second strain-gauge element, and the third signal. ### Claim 11 (depends on 10) The deformation sensing apparatus of claim 10, wherein: the first signal is indicative of a first resistance of the first strain-gauge element; the second signal is indicative of a second resistance of the second strain-gauge element; and the third signal is indicative of a capacitance across the substrate measured responsive to the applied deformation. ### Claim 12 (depends on 11) The deformation sensing apparatus of claim 11, wherein the deformation analyzer computes the measure of stretch deformation as a proportion of length change ((ΔL)/L0) of the first and second strain-gauge elements, based on the first, second, and third signals, using the equations: R 1 = R 2 = R 0 + ( GF · Δ ⁢ ⁢ L ) C = ℰ ⁢ Area gap = ℰ = L 0 · W 0 g = ℰ ⁢ L 0 · W 0 ( g 0 - Δ ⁢ ⁢ L · ) = ℰ ⁢ L 0 · W 0 ( g 0 - ( Δ ⁢ ⁢ L 1 + Δ ⁢ ⁢ L 2 2 ) ⁢ ) , where R1 is the first resistance, R2 is the second resistance, C is the capacitance, and Area is an overlap between first and second strain-gauge elements, GF is a Gauge Factor relating strain and resistance, γ is a Poisson's Ratio of the substrate relating deformations between axes, L0 is an undeformed length of the first and second strain-gauge elements, ΔL, ΔL1, ΔL2 are length changes of the first and second strain-gauge elements, W0 is an undeformed length of the first and second strain-gauge elements, ε is a dielectric constant of the substrate, R0 is a baseline resistance of the first and second strain-gauge elements, and g, g0 are, respectively, deformed and baseline widths of the substrate. ### Claim 13 (depends on 11) The deformation sensing apparatus of claim 11, wherein the deformation analyzer computes the measure of flex deformation as bend radii of the first and second strain-gauge elements, based on the first, second, and third signals, using the equations: R 1 = R 0 + ( GF · Δ ⁢ ⁢ L 1 ) ≈ R 0 + ( g 2 ⁢ ⁢ ρ 1 · GF ) R 2 = R 0 + ( GF · Δ ⁢ ⁢ L 2 ) ≈ R 0 + ( - g 2 ⁢ ⁢ ρ 2 · GF ) , where R1 is the first resistance, R2 is the second resistance, and GF is a Gauge Factor relating strain and resistance of the first and second strain-gauge elements, γ is a Poisson's Ratio of the substrate relating deformations between axes, L0 is an undeformed length of the first and second strain-gauge elements, ΔL1, ΔL2 are length changes of the first and second strain-gauge elements, R0 is a baseline resistance of the first and second strain-gauge elements, g, is a deformed width of the substrate, and ρ1 and ρ2 are bend radii of the first portion and the second portion of the substrate. ### Claim 14 A system comprising: one or more deformation sensors, each including: a substrate; a first strain-gauge element coupled to first portion of the substrate, and configured to output a first signal in response to a strain applied in a first direction; and a second strain-gauge element coupled to a second portion of the substrate opposite to the first portion, and configured to output a second signal in response to a strain applied in the same first direction, wherein the deformation sensor is configured to output a third signal responsive to an applied deformation, the third signal being measurable between one of the first and second terminals of the first strain-gauge element and one of the third and fourth terminals of the second strain-gauge element; a measurement circuit configured to measure the first signal from the first strain-gauge element and the second signal from the second strain-gauge element in response to the applied deformation; and a deformation analyzer configured to compute a measure of stretch deformation and a measure of flex deformation of the sensing apparatus, in the applied deformation, based on the measured first signal from the first strain-gauge element, the measured second signal of the second strain-gauge element, and the third signal. ### Claim 15 (depends on 14) The system of claim 14, wherein: each of the first and second strain-gauge elements of the deformation sensor has a horse-shoe shape comprising an arcuate head and a pair of elongate leads extending from ends of the arcuate head; and alignment of the shapes of the first and second strain-gauge elements correspond and the shapes are configured to circumscribe an articulating joint, a movement of the joint resulting in a corresponding deformation of the deformation sensor. ### Claim 16 (depends on 14) The system of claim 14, wherein the one or more deformation sensors are included in a wearable device. ### Claim 17 (depends on 14) The system of claim 14, wherein the one or more deformation sensors are included in a glove. ### Claim 18 (depends on 17) The system of claim 17, wherein the one or more deformation sensors are included in a finger of the glove. ### Claim 19 (depends on 17) The system of claim 17, wherein the one or more deformation sensors comprise a plurality of deformation sensors, each included in a different finger of the glove. ### Claim 20 A method of sensing deformation of a deformation sensor, comprising, in response to an applied deformation: measuring a first signal from a first strain-gauge element coupled to a first portion of an substrate of the deformation sensor, the first signal indicative of a resistance of the first strain-gauge element; measuring a second signal from a second strain-gauge element coupled to a second portion of the substrate of the deformation sensor, the second signal indicative of a resistance of the second strain-gauge element; measuring a third signal between the first strain-gauge element and the second strain-gauge element, the third signal indicative of a capacitance across the substrate measured responsive to the applied deformation; and computing a measure of stretch deformation and a measure of flex deformation of the deformation sensor, in the applied deformation, based on the measured first signal from the first strain-gauge element, the measured second signal of the second strain-gauge element, and the third signal.