Configurable photoplethysmogram system
Inventors
Vallius, Tero Juhani • Heikkinen, Olli Petteri • Järvelä, Jussi Petteri • Huttunen, Heikki Juhani • Haverinen, Teemu Juhani • Rantanen, Antti Aleksi • Pelkonen, Sami Seppo • Syrjälä, Juha-Pekka • Koskela, Markku Olavi
Assignees
Publication Number
US-12074637-B2
Publication Date
2024-08-27
Expiration Date
2042-10-11
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Abstract
Methods, systems, and devices for optical signal measurement are described. A wearable electronic device may activate a first combination of optical sensors, the first combination of optical sensors including a set of transmitter sensors and a set of receiver sensors. In some cases, one or more optical sensor of the first combination of optical sensors may be positioned under a protrusion on an inner surface of the wearable electronic device. The device may measure, at the set of receiver sensors at a first time, one or more signals from the set of transmitter sensors, determine a signal quality metric associated with the one or more signals, and select a second combination of optical sensors for use at a second time based on the signal quality metric.
Core Innovation
The invention provides methods, systems, and devices for optical signal measurement in wearable electronic devices, specifically through a configurable photoplethysmogram (PPG) system. The wearable device activates a first combination of optical sensors, consisting of sets of transmitter and receiver sensors, where at least one optical sensor is positioned under a protrusion on the inner surface of the device. The device measures signals from the transmitters, calculates a signal quality metric, and selects a different combination of optical sensors for use thereafter based on this metric.
The problem addressed by this invention is the limitation and need for improvement in existing techniques for collecting PPG data using sensors on wearable devices. Factors such as motion, device positioning on the skin, ambient light, and user movement negatively affect the quality of the PPG signals. Selecting transmitter and receiver combinations adaptively, including switching among multiple wavelengths (e.g., infrared, red, green), helps improve signal accuracy. The system dynamically adjusts sensor activation, sampling rates, and power levels to optimize measurement accuracy and device power consumption.
Claims Coverage
The patent includes one independent method claim and one independent apparatus claim, covering innovative techniques for dynamic selection and activation of optical sensors in a wearable electronic device.
Dynamic activation of optical sensor combinations
Activating a first combination of optical sensors comprising transmitter and receiver sensors of multiple wavelengths, positioned under a protrusion on the inner surface of the wearable electronic device.
Measurement and assessment of optical signals
Measuring signals at the receiver sensors from the transmitter sensors and determining a signal quality metric associated with those signals.
Adaptive selection of sensor combinations
Selecting a second combination of optical sensors for use at a later time based at least in part on the signal quality metric.
Structural arrangement of sensors and protrusions
The placement of photodiodes and LEDs of different wavelengths under protrusions on the inner surface, including specific positioning where green LEDs flank photodiodes and infrared and red LEDs are collocated.
Selection criteria and parameters adjustment
Switching between wavelengths based on factors such as signal quality, time of day, user motion, temperature, and updating measurement parameters such as sampling rate, power output, and sensor activation time.
Ring fit and wearing detection
Detecting ambient light levels and using dedicated infrared LEDs for finger wearing detection to identify ring fit metrics and determine if the device is being worn.
The claims comprehensively cover the invention's technical features for dynamically activating, measuring, evaluating, and selecting optical sensor combinations in a wearable device, with structures and parameters arranged to optimize PPG signal measurement and device usability.
Stated Advantages
Improved accuracy of PPG signal measurement through adaptive selection of transmitter-receiver sensor combinations based on measured signal quality.
Enhanced device performance by dynamically adjusting measurement parameters such as sampling rate and power output to optimize battery life and signal quality.
Improved signal acquisition under varying conditions including user movement, time of day, and ambient temperature by using multiple wavelengths and sensor arrangements.
Increased robustness against device orientation and fit issues by placing sensors under protrusions and using ring fit metrics derived from ambient light and accelerometer data.
Superior physiological data collection compared to wrist-worn devices due to better access to finger arteries and strategic placement of optical sensors.
Documented Applications
Wearable devices such as rings and watches for continuous physiological data collection including heart rate, heart rate variability, respiratory rate, and blood oxygen levels.
Sleep stage classification by analyzing physiological data collected during sleep via PPG measurements.
Health and readiness scoring systems that use continuous physiological monitoring to provide user feedback.
Detection of device fit and wearing status using ambient light detection and dedicated infrared LEDs.
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