Intersection cross-cut: ring ∩ sensor-ppg

Axes: form_factor × sensors

7 corpus entries disclose both tags.

Earliest disclosure: 1973

These entries are the direct inputs to OBVIOUSNESS_TEMPLATE.md. Any patent claim combining these two elements is anticipated or rendered obvious by the chain below.

Peñáz (1973) — the volume-clamp (vascular unloading) method of continuous finger blood pressure (1973)

  • id: penaz-1973-volume-clamp-finger-bp
  • corpus: academic
  • form factor: other
  • creator: Jan Peñáz
  • disclosure: Peñáz J. ‘Photoelectric measurement of blood pressure, volume and flow in the finger.’ Digest of the 10th International Conference on Medical and Biological Engineering, Dresden, 1973, p. 104. (Basis of the Finapres / volume-clamp continuous BP monitors.)
  • ip status: public-domain
  • sensors: sensor-ppg, sensor-cuffless-bp-volume-clamp, sensor-pressure-skin
  • algorithms: algo-pwv-bp-estimation
  • prior art notes: Discloses the volume-clamp / vascular-unloading method: a finger cuff servo-controlled by a photoplethysmographic feedback loop to hold the arterial volume constant, so the applied counter-pressure tracks the arterial pressure waveform continuously and non-invasively. Any cuffless/continuous-BP wearable claim reciting ‘a photoplethysmographic feedback loop controlling an applied pressure to maintain constant vascular volume’ reads on Peñáz 1973. Anchor for the volume-clamp cuffless-BP cross-cut (the finger/ring form-factor variants are obvious combinations under [[obviousness-template]]).

MIT wearable ring sensor (Rhee, Yang, Asada) — finger-ring PPG for ambulatory monitoring (2001-07)

  • id: asada-mit-wearable-ring-sensor-2003
  • corpus: academic
  • form factor: ring
  • creator: Sokwoo Rhee / Boo-Ho Yang / Haruhiko Harry Asada (MIT d’Arbeloff Lab)
  • disclosure: Rhee S, Yang B-H, Asada HH. ‘Artifact-resistant power-efficient design of finger-ring plethysmographic sensors.’ IEEE Transactions on Biomedical Engineering 2001;48(7):795-805 (and Asada HH, Shaltis P, Reisner A, Rhee S, Hutchinson RC. ‘Mobile monitoring with wearable photoplethysmographic biosensors.’ IEEE Engineering in Medicine and Biology Magazine 2003;22(3):28-40).
  • ip status: patented
  • sensors: sensor-ppg, sensor-accelerometer
  • algorithms: algo-hr, algo-spo2-estimation
  • prior art notes: Discloses a finger-ring-form-factor wearable PPG sensor with motion-artifact-resistant optical/mechanical design, low-power operation, on-body processing, and wireless telemetry of heart rate and SpO2 for ambulatory monitoring — i.e. the smart-ring physiological monitor, ~14 years before the commercial smart-ring wave. Directly anticipates ring-form claims combining ‘a ring body’, ‘a PPG emitter/detector at the inner ring surface’, ‘motion-artifact compensation’, and ‘wireless transmission of derived vitals’. Anchor for the ring × PPG cross-cut; [[oura-ring-gen1-2015]] and similar products descend from it.

Oura Ring (Gen 1, 2015) — finger-ring PPG, skin-temperature and accelerometer for HRV, sleep and body temperature (2015-08)

  • id: oura-ring-gen1-2015
  • corpus: private
  • form factor: ring
  • creator: Oura Health Oy
  • disclosure: Oura Health Oy. ‘Oura Ring’ (1st generation), crowdfunded 2015, shipped 2016 — a titanium finger ring with infrared photoplethysmography, an NTC skin-temperature sensor, and a 3-axis accelerometer, deriving resting heart rate, heart-rate variability, respiratory rate, sleep staging, and body-temperature trend.
  • ip status: patented
  • sensors: sensor-ppg, sensor-skin-temperature, sensor-accelerometer
  • algorithms: algo-hr, algo-hrv, algo-respiratory-rate, algo-sleep-staging
  • prior art notes: Discloses a finger-ring wearable with infrared PPG, a skin-temperature sensor, and an accelerometer, deriving resting HR, HRV, respiratory rate, sleep stages, and a body-temperature trend, with companion-app readout. A commercial realization, ~12-16 years later, of the MIT ring-sensor concept ([[asada-mit-wearable-ring-sensor-2003]]); to the extent later claims recite ring-form PPG + skin-temperature + HRV/sleep, both Asada 2003 and Oura 2015 are prior art. Product-side anchor for the ring × PPG × HRV and ring × skin-temperature cross-cuts.

Mukkamala et al. (2015) — ‘Toward Ubiquitous Blood Pressure Monitoring via Pulse Transit Time: Theory and Practice’ (2015-08)

  • id: mukkamala-2015-ptt-cuffless-bp-review
  • corpus: academic
  • form factor: other
  • creator: Ramakrishna Mukkamala et al.
  • disclosure: Mukkamala R, Hahn J-O, Inan OT, Mestha LK, Kim C-S, Töreyin H, Kyal S. ‘Toward Ubiquitous Blood Pressure Monitoring via Pulse Transit Time: Theory and Practice.’ IEEE Transactions on Biomedical Engineering 2015;62(8):1879-1901.
  • ip status: public-domain
  • sensors: sensor-ecg, sensor-ppg, sensor-cuffless-bp-ptt, sensor-cuffless-bp-tonometry
  • algorithms: algo-pwv-bp-estimation
  • prior art notes: Canonical 2015 review of cuffless blood-pressure estimation by pulse transit time / pulse arrival time / pulse wave velocity: the physiological models, the practical sensor configurations (ECG+PPG, dual PPG, ballistocardiogram+PPG), the calibration strategies, and the accuracy limitations. Prior art for cuffless-BP wearable claims reciting any of the configurations or calibration approaches surveyed here — they were collected, modeled, and published by 2015. Combined with watch/ring/patch form-factor disclosures, makes wearable PTT-based BP an obvious combination under [[obviousness-template]].

Heikenfeld et al. (2018) — ‘Wearable sensors: modalities, challenges, and prospects’ (2018-01-16)

  • id: heikenfeld-2018-wearable-sensors-lab-on-chip-review
  • corpus: academic
  • form factor: other
  • creator: Jason Heikenfeld et al.
  • disclosure: Heikenfeld J, Jajack A, Rogers J, Gutruf P, Tian L, Pan T, Li R, Khine M, Kim J, Wang J, Kim J. ‘Wearable sensors: modalities, challenges, and prospects.’ Lab on a Chip 2018;18(2):217-248.
  • ip status: public-domain
  • sensors: sensor-ppg, sensor-ecg, sensor-eeg, sensor-glucose-cgm, sensor-lactate, sensor-cortisol, sensor-skin-temperature, sensor-bioimpedance
  • prior art notes: Authoritative 2018 review collecting wearable sensing across modalities — physical (motion, BCG/SCG, mechanoacoustic), electrophysiological (ECG/EMG/EEG), optical (PPG/SpO2, near-IR), thermal, electrochemical (sweat, saliva, tears, interstitial), and stimulation-coupled — across form factors (patch, watch, tattoo, contact lens, garment) and the challenges of body-fluid sampling, calibration, motion-artifact handling, and skin-electronics interfacing. Prior art establishing that the modality/form-factor combinations enumerated here were collected and surveyed by 2018; useful against later claims to those combinations. General anchor.

Ultrahuman Ring AIR (2023) — smart ring with metabolic-focus tracking (PPG, skin temperature, IMU) (2023)

  • id: ultrahuman-ring-air-2023
  • corpus: private
  • form factor: ring
  • creator: Ultrahuman Healthcare Pvt. Ltd.
  • disclosure: Ultrahuman Healthcare Pvt. Ltd. ‘Ultrahuman Ring AIR’, launched 2023 — a titanium smart ring with infrared photoplethysmography, IR skin-temperature, and a 6-axis IMU, deriving HR, HRV, skin temperature, sleep staging, activity, and metabolic-health framing (paired with the company’s CGM-based metabolism platform).
  • ip status: patented
  • sensors: sensor-ppg, sensor-skin-temperature, sensor-accelerometer, sensor-gyroscope
  • algorithms: algo-hr, algo-hrv, algo-sleep-staging, algo-respiratory-rate
  • prior art notes: Discloses a smart ring with IR PPG, skin-temperature, and a 6-axis IMU, deriving HR/HRV, sleep, and activity, packaged with a metabolic-health platform (CGM-linked). Product-side reference in the ring × PPG cross-cut alongside [[oura-ring-gen1-2015]] and [[samsung-galaxy-ring-2024]].

Samsung Galaxy Ring (2024) — smart ring with PPG, skin temperature and accelerometer for HR/HRV, sleep and cycle tracking (2024-07-10)

  • id: samsung-galaxy-ring-2024
  • corpus: private
  • form factor: ring
  • creator: Samsung Electronics Co., Ltd.
  • disclosure: Samsung Electronics. ‘Samsung Galaxy Ring’, announced July 2024 — a finger ring with infrared photoplethysmography, an IR skin-temperature sensor, and a 3-axis accelerometer, deriving heart rate, heart-rate variability, skin temperature, sleep staging, activity, snore detection, and (with cycle-tracking) menstrual-cycle predictions.
  • ip status: patented
  • sensors: sensor-ppg, sensor-skin-temperature, sensor-accelerometer
  • algorithms: algo-hr, algo-hrv, algo-respiratory-rate, algo-sleep-staging, algo-snore-detection, algo-step-count
  • prior art notes: Discloses a smart ring with infrared PPG, IR skin-temperature, and accelerometer, deriving HR/HRV, sleep, snore detection, activity, and menstrual-cycle prediction — a Samsung entry directly in the wake of [[oura-ring-gen1-2015]] and the [[asada-mit-wearable-ring-sensor-2003]] academic root. Product-side reference in the ring × PPG × HRV cross-cut alongside Oura.

Public domain (CC0 1.0). The corpus IS the prior art commons.

This site uses Just the Docs, a documentation theme for Jekyll.