# US 2017/0289722 A1 · System and method for generating spatial sound using ultrasound > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0289722 A1 - Document ID: US20170289722A1 - Status: Published application - Kind: A1 - Application number: 15/089,879 - Filed: 2016-04-04 - Published: 2017-10-05 - Earliest claimed: 2016-04-04 - Assignees: Pixie Dust Technologies, Inc. - Applicants: Pixie Dust Technologies, Inc. - Inventors: Yoichi OCHIAI; Takayuki HOSHI - Web page: https://patentgrep.com/patent/US20170289722A1 ## CPC - H04S 7/30: {Control circuits for electronic adaptation of the sound field} - H04R 1/403: {loud-speakers} - H04R 3/12: for distributing signals to two or more loudspeakers {(specially adapted for hearing aids H04R25/407)} - H04R 2201/401: 2D or 3D arrays of transducers - H04R 2217/03: Parametric transducers where sound is generated or captured by the acoustic demodulation of amplitude modulated ultrasonic waves - H04R 2430/20: Processing of the output signals of the acoustic transducers of an array for obtaining a desired directivity characteristic (H04R2203/12 takes precedence) - H04S 1/002: {Non-adaptive circuits, e.g. manually adjustable or static, for enhancing the sound image or the spatial distribution (control circuits for electronic adaptation of the sound field H04S7/30)} - H04S 2400/11: Positioning of individual sound objects, e.g. moving airplane, within a sound field (H04S2420/13 takes precedence) - H04S: STEREOPHONIC SYSTEMS - H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K) ## Abstract A novel system and method for spatial sound generation is disclosed. A system and method for generating bodiless mid-air speakers includes the steps of: generating a modulated signal by modulating an ultrasonic carrier signal with an audio signal, determining a phase delay value for each ultrasonic transducer of an array of ultrasonic transducers with respect to one or more focal points, and driving each such ultrasonic transducer with the modulated signal in accordance with the phase delay value determined for each ultrasonic transducer to generate audible sound at the one or more focal points. ## Claims ### Claim 1 A method for generating bodiless mid-air speakers comprising the steps of: generating a modulated signal by modulating an ultrasonic carrier signal with an audio signal; determining a phase delay value for each ultrasonic transducer of an array of ultrasonic transducers with respect to one or more focal points; and driving each such ultrasonic transducer with the modulated signal in accordance with the phase delay value determined for each ultrasonic transducer to generate audible sound at the one or more focal points. ### Claim 2 (depends on 1) The method of claim 1, wherein said ultrasonic carrier signal is a sine wave having a frequency of at least 20 kHz. ### Claim 3 (depends on 1) The method of claim 1, wherein the phase delay value for each ultrasonic transducer is determined in accordance with the equation Δtij=(l00−lij)/c, wherein Δtij represents a time delay for the application of a drive signal to an ultrasonic transducer. ### Claim 4 (depends on 1) The method of claim 1, wherein the phase delay value for each ultrasonic transducer is determined in accordance with equation Uh(x, y)=αh(x, y) exp [iφh(x, y)], where φh(x, y) represents the phase delay value. ### Claim 5 (depends on 1) The method of claim 1, wherein said modulated signal is generated by amplitude modulation. ### Claim 6 (depends on 1) The method of claim 1, wherein said modulated signal is generated by frequency modulation. ### Claim 7 (depends on 1) The method of claim 1, wherein audible sound can only be heard within about 50 cm of the one or more focal points. ### Claim 8 (depends on 1) The method of claim 1, wherein the one or more focal points are adjacent to a person's ear. ### Claim 9 (depends on 1) The method of claim 1, wherein the one or more focal points are adjacent to an object or image so as to make it appear as if the object or image is the source of the audible sound. ### Claim 10 (depends on 1) The method of claim 1 comprising the additional steps of: changing the spatial position of one or more focal points; determining a new phase delay value for each ultrasonic transducer of an array of ultrasonic transducers with respect to the one or more focal points; and driving each ultrasonic transducer with the modulated signal in accordance with said new phase delay value determined for each ultrasonic transducer to generate audible sound at the one or more focal points. ### Claim 11 A bodiless mid-air speakers generator, comprising: one or more ultrasonic phased arrays, each ultrasonic phase array comprising: an array of ultrasonic transducers; a signal generator that generates a modulated signal by modulating an ultrasonic carrier signal with an audio signal; a phase delay calculator that determines a phase delay value for each ultrasonic transducer of the array of ultrasonic transducers with respect to one or more focal points; and a driving circuit for applying the modulated signal to each ultrasonic transducer in accordance with the phase delay value determined for each such ultrasonic transducer to generate audible sound at the one or more focal points. ### Claim 12 (depends on 11) The bodiless mid-air speakers generator of claim 11, wherein said ultrasonic carrier signal is a sine wave having a frequency of at least 20 kHz. ### Claim 13 (depends on 11) The bodiless mid-air speakers generator of claim 11, wherein the phase delay value for each ultrasonic transducer is determined in accordance with the equation Δtij=(l00−lij)/c, wherein Δtij represents a time delay for the application of a drive signal to an ultrasonic transducer. ### Claim 14 (depends on 11) The bodiless mid-air speakers generator of claim 11, wherein the phase delay value for each ultrasonic transducer is determined in accordance with equation Uh(x, y)=αh(x, y) exp [iφh(x, y)], where φh(x, y) represents the phase delay value. ### Claim 15 (depends on 11) The bodiless mid-air speakers generator of claim 11, wherein said signal generator comprises an amplitude modulation unit. ### Claim 16 (depends on 11) The bodiless mid-air speakers generator of claim 11, wherein said signal generator comprises a frequency modulation unit. ### Claim 17 (depends on 11) The bodiless mid-air speakers generator of claim 11, further comprising an output power control circuit to adjust the volume of the audible sound. ### Claim 18 (depends on 11) The bodiless mid-air speakers generator of claim 11, wherein each phased array has at least 285 ultrasonic transducers. ### Claim 19 (depends on 11) The bodiless mid-air speakers generator of claim 11, wherein the phase delay calculator determines a new phase delay value for each ultrasonic transducer of the array of ultrasonic transducers with respect to any change in the spatial position of the one or more focal points. ### Claim 20 A method for generating bodiless mid-air speakers comprising the steps of: generating a first modulated signal by modulating an ultrasonic carrier signal with a first audio signal; generating a second modulated signal by modulating an ultrasonic carrier signal with a second audio signal; determining a phase delay value for each ultrasonic transducer of a first group of transducers of an array of ultrasonic transducers with respect to a first focal point; determining a phase delay value for each ultrasonic transducer of a second group of transducers of the array of ultrasonic transducers with respect to a second focal point; driving each such ultrasonic transducer of the first group of transducers with the first modulated signal in accordance with the phase delay value determined for each such ultrasonic transducer of the first group to generate audible sound at the first focal point; and driving each such ultrasonic transducer of the second group of transducers with the second modulated signal in accordance with the phase delay value determined for each such ultrasonic transducer of the second group to generate audible sound at the second focal point.