# US 12,216,865 B2 · Contactless element detection device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,216,865 B2 - Document ID: US12216865B2 - Status: Granted - Kind: B2 - Application number: 18/254,481 - Filed: 2021-11-24 - Published: 2024-02-15 - Granted: 2025-02-04 - Earliest claimed: 2020-11-26 - Assignees: Commissariat A L'energie Atomique Et Aux Energies Alternatives - Applicants: Commissariat A L'energie Atomique Et Aux Energies Alternatives - Inventors: Pierre-Henri Orefice; Charles Hudin - Web page: https://patentgrep.com/patent/US12216865B2 ## CPC - G06F 3/043: using propagating acoustic waves - G01R 23/02: Arrangements for measuring frequency, e.g. pulse repetition rate; Arrangements for measuring period of current or voltage - G01S 15/66: Sonar tracking systems - G01S 15/876: {Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector (G01S15/872 takes precedence)} - G06F 3/017: {Gesture based interaction, e.g. based on a set of recognized hand gestures (interaction based on gestures traced on a digitiser G06F3/04883)} - G06F 2203/04108: Touchless 2D- digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface without distance measurement in the Z direction - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES ## Abstract A contactless detection device, comprising a detection surface; a plurality of actuators acoustically coupled to the detection surface; an ultrasonic acoustic wave detector; an electronic and/or IT computer, the device being configured to detect one or more element(s) by repeating the following steps: focusing ultrasonic acoustic waves emitted by the actuators into a focusing region, obtained from waves emitted by the actuators and to which a first time reversal method has been applied, and measuring a duration between emitting the waves and receiving an echo of these waves by the detector, wherein the computer is configured to calculate the control signals such that the detection waves are focused successively into focusing regions of different shape and/or sizes. ## Claims ### Claim 1 A contactless detection device, comprising: a detection surface; a plurality of actuators acoustically coupled to the detection surface and configured to emit ultrasonic acoustic waves; an ultrasonic acoustic wave detector; and processing circuitry; wherein the device is configured to perform detection of one or more elements by implementing the following steps a plurality of times: focusing detection ultrasonic acoustic waves emitted by the plurality of actuators via the detection surface into a focusing region belonging to a plane located opposite and away from the detection surface, by applying on the plurality of actuators, control signals calculated by the processing circuitry from a measurement of an audio impulse response and/or a vibratory impulse response of the detection surface that was generated by an emission of ultrasonic calibration acoustic waves by each of the plurality of actuators, and application of a first time reversal method to the audio impulse response and/or to the vibratory impulse response of the detection surface, and measuring a duration between the emission of the detection ultrasonic acoustic waves and a reception of an echo of the detection ultrasonic acoustic waves by the ultrasonic acoustic wave detector, wherein the processing circuitry is further configured to calculate the control signals such that the detection ultrasonic acoustic waves are focused successively into focusing regions having different shapes and/or dimensions. ### Claim 2 (depends on 1) The contactless detection device according to claim 1, wherein the detection surface corresponds to a first face of a material plate, and wherein the plurality of actuators are secured to a second face, opposite to the first face, of the material plate. ### Claim 3 (depends on 2) The contactless detection device according to claim 2, wherein the material plate has a thickness between 0.1 mm and 3 mm and/or includes a material whose Young's modulus is between 50 GPa and 300 GPa, and/or such that a ratio of a volumetric mass of the material plate to the Young's modulus of the plate material is between 20.10−8 kg/m·N and 50.10−8 kg/m·N. ### Claim 4 (depends on 1) The contactless detection device according to claim 1, wherein the ultrasonic acoustic wave detector includes at least one microphone and/or acoustic transducers disposed over the detection surface. ### Claim 5 (depends on 1) The contactless detection device according to claim 1, wherein the ultrasonic acoustic wave detector is formed by the plurality of actuators configured to emit the ultrasonic acoustic waves, and which are further configured to perform an acoustic transduction. ### Claim 6 (depends on 5) The contactless detection device according to claim 5, wherein the processing circuitry is further configured to apply a second time reversal method to the echo of the detection ultrasonic acoustic waves received by each of the plurality of actuators. ### Claim 7 (depends on 1) The contactless detection device according to claim 1, wherein the plurality of actuators are configured to emit ultrasonic acoustic waves whose frequencies are between 20 kHz and 100 kHz. ### Claim 8 (depends on 1) The contactless detection device according to claim 1, wherein the processing circuitry is further configured to measure a frequency shift between the emitted detection ultrasonic acoustic waves and the echo of the detection ultrasonic acoustic waves, and calculate a speed of movement of the detected elements from the measured frequency shift. ### Claim 9 (depends on 1) The contactless detection device according to claim 1, wherein the processing circuitry is further configured to encode the control signals prior to the emission of the ultrasonic acoustic waves. ### Claim 10 (depends on 1) A contactless interaction device, comprising: the contactless detection device according to claim 1, and circuitry configured to perform one or more actions according to a result of the detection performed by the contactless detection device. ### Claim 11 (depends on 10) The contactless interaction device according to claim 10, the contactless interaction device forming a human-machine interface comprising a display surface to which the detection surface of the contactless detection device is secured. ### Claim 12 (depends on 1) A method for controlling a contactless detection device according to claim 1, the method comprising: calculating, by the processing circuitry, the control signals from the measurement of the audio impulse response and/or the vibratory impulse response of the detection surface that was generated by the emission of the calibration ultrasonic acoustic waves emitted by each of the plurality of actuators, and the application of a first time reversal method to the audio impulse response and/or to the vibratory impulse response of the detection surface, applying the calculated control signals on the plurality of actuators, focusing the detection ultrasonic acoustic waves emitted by the plurality of actuators into the focusing region belonging to the plane opposite the detection surface, and measuring the duration between the emission of the detection ultrasonic acoustic waves and the reception of the echo of the detection ultrasonic acoustic waves by the ultrasonic acoustic wave detector, wherein the above steps are repeated the plurality of times such that the calculated control signals focus the detection ultrasonic acoustic waves successively into focusing regions having the different shapes and/or dimensions. ### Claim 13 (depends on 12) The method according to claim 12, further comprising calibrating the contactless detection device comprising by: emitting the calibration ultrasonic acoustic waves by each of the plurality of actuators; measuring the audio impulse response and/or the vibratory impulse response of the detection surface generated by the emission of the calibration ultrasonic acoustic waves; applying the first time reversal method to the audio impulse response and/or to the vibratory impulse response of the detection surface; and storing the signals obtained by applying the first time reversal method to the audio impulse response and/or to the vibratory impulse response of the detection surface. ### Claim 14 (depends on 12) The method according to claim 12, further comprising detecting a position or a movement of one or more fingers of a user of the contactless detection device.