# US 2021/0275038 A1 · Wearable device for sensing vital signs > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0275038 A1 - Document ID: US20210275038A1 - Status: Published application - Kind: A1 - Application number: 17/182,355 - Filed: 2021-02-23 - Published: 2021-09-09 - Earliest claimed: 2020-03-05 - Assignees: Welch Allyn, Inc. - Applicants: Welch Allyn, Inc. - Inventors: Lei Guo; Thaddeus J. Wawro - Web page: https://patentgrep.com/patent/US20210275038A1 ## CPC - A61B 5/0205: Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition - A61B 5/6823: {Trunk, e.g., chest, back, abdomen, hip} - A61B 5/021: Measuring pressure in heart or blood vessels - A61B 5/02141: {Details of apparatus construction, e.g. pump units or housings therefor, cuff pressurising systems, arrangements of fluid conduits or circuits (A61B5/02233, A61B5/0235 take precedence)} - A61B 5/02427: {Details of sensor} - A61B 5/14551: {for measuring blood gases} - A61B 5/14552: {Details of sensors specially adapted therefor} - A61B 5/7282: {Event detection, e.g. detecting unique waveforms indicative of a medical condition (cough events A61B5/0823; seizures A61B5/4094; sleep apnoea A61B5/4818)} - A61B 7/04: Electric stethoscopes - A61B 5/0022: {Monitoring a patient using a global network, e.g. telephone networks, internet} - A61B 5/02125: {of pulse wave propagation time} - A61B 5/14546: {for measuring analytes not otherwise provided for, e.g. ions, cytochromes} - A61B 5/7207: {of noise induced by motion artifacts} - A61B 5/746: {Alarms related to a physiological condition, e.g. details of setting alarm thresholds or avoiding false alarms} - A61B 2562/0204: Acoustic sensors - A61B 2562/0242: for varying or adjusting the optical path length in the tissue - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract A wearable device for sensing vital signs includes a housing defining an interior cavity. An optical unit is positioned inside the interior cavity. The optical unit includes one or more light emitters that emit optical signals, at least one polarizer orientated to block optical signals having a predetermined polarity direction, and one or more light sensors that receive optical signals that pass through the at least one polarizer. An acoustic unit is positioned inside the interior cavity, and has a microphone to receive acoustic signals that enter into the interior cavity. The acoustic signals are used to non-invasively estimate blood pressure. ## Claims ### Claim 1 A wearable device for sensing vital signs comprising: a housing defining an interior cavity; an optical unit positioned inside the interior cavity, the optical unit having: one or more light emitters that emit optical signals; at least one polarizer orientated to block optical signals having a predetermined polarity direction; and one or more light sensors that receive optical signals that pass through the at least one polarizer; and an acoustic unit positioned inside the interior cavity, the acoustic unit having: a microphone to receive acoustic signals that enter into the interior cavity, the acoustic signals being used to non-invasively estimate blood pressure. ### Claim 2 (depends on 1) The device of claim 1, wherein the one or more light emitters emit polarized optical signals. ### Claim 3 (depends on 1) The device of claim 1, wherein the polarizer polarizes the optical signals emitted from the one or more light emitters. ### Claim 4 (depends on 1) The device of claim 1, wherein the interior cavity has a concave profile that defines an apex opposite an opening, and the optical unit and acoustic unit are mounted at the apex. ### Claim 5 (depends on 1) The device of claim 1, wherein the interior cavity has a reflective interior surface. ### Claim 6 (depends on 1) The device of claim 1, wherein the optical unit includes first and second polarizers each mounted over the light emitters and light sensors, the first polarizer is orientated to polarize the optical signals emitted from the one or more light emitters in a first polarity direction, and the second polarizer is orientated with respect to the first polarizer such that the second polarizer blocks optical signals that are reflected back in the first polarity direction, and the one or more light sensors receive optical signals that pass through the second polarizer. ### Claim 7 (depends on 6) The device of claim 6, wherein the first and second polarizers are axially aligned about a central axis of the interior cavity. ### Claim 8 (depends on 7) The device of claim 7, wherein the second polarizer is shifted 90 degrees with respect to the first polarizer. ### Claim 9 (depends on 8) The device of claim 8, wherein the first and second polarizers each includes an aperture allowing the acoustic signals to pass through the first and second polarizers. ### Claim 10 (depends on 9) The device of claim 9, further comprising a circuit board having an aperture forming a passageway with the apertures of the first and second polarizers, the passageway allowing the acoustic signals to reach the microphone which is positioned on an opposite side of the circuit board as the one or more light emitters and the one or more light sensors. ### Claim 11 (depends on 6) The device of claim 6, wherein the first and second polarizers are each circular discs having one or more cutouts corresponding to locations of the one or more light emitters and the one or more light sensors, respectively. ### Claim 12 (depends on 11) The device of claim 11, wherein the one or more cutouts of the first polarizer are positioned over the one or more light sensors, the one or more light emitters are covered by the first polarizer, and the one or more the light sensors are not covered by the first polarizer. ### Claim 13 (depends on 12) The device of claim 12, wherein the one or more cutouts of the second polarizer are positioned over the one or more light emitters, the one or more light sensors are covered by the second polarizer, and the one or more light emitters are not covered by the second polarizer. ### Claim 14 (depends on 1) The device of claim 1, wherein the optical signals received by the one or more light sensors are used to non-invasively measure peripheral oxygen saturation. ### Claim 15 (depends on 14) The device of claim 14, wherein the wearable device non-invasively measures the blood pressure and peripheral oxygen saturation simultaneously. ### Claim 16 A wearable device for sensing vital signs comprising: a housing defining an interior cavity; an optical unit positioned inside the interior cavity, the optical unit having: one or more light emitters that emit optical signals; a first polarizer orientated to polarize the optical signals emitted from the one or more light emitters in a first polarity direction; a second polarizer orientated with respect to the second polarizer to block optical signals reflected in the first polarity direction; and one or more light sensors that receive reflected optical signals that pass through the second polarizer, the reflected optical signals being used to non-invasively measure peripheral oxygen saturation. ### Claim 17 (depends on 16) The wearable device of claim 16, further comprising an acoustic unit positioned inside the interior cavity, the acoustic unit having a microphone to receive acoustic signals that enter into the interior cavity, the acoustic signals being used to non-invasively estimate blood pressure. ### Claim 18 A method for obtaining vital signs, comprising: emitting polarized optical signals; filtering optical signals that do not penetrate into a tissue; receiving the filtered optical signals; and using the filtered optical signals to measure a vital sign. ### Claim 19 (depends on 18) The method of claim 18, where the vital sign is peripheral oxygen saturation. ### Claim 20 (depends on 18) The method of claim 18, where the vital sign is blood pressure.