Multiple light paths architecture, obscuration methods for signal and perfusion index optimization

Abstract

The application relates to a multiple light paths architecture, obscuration methods for a signal and perfusion index optimization. Specifically, a photoplethysmographic (PPG) device is disclosed. The PPG device can include one or more light emitters and one or more light sensors to generate the multiple light paths for measuring a PPG signal and perfusion indices of a user. The multiple light paths between each pair of light emitters and light detectors can include different separation distances to generate both an accurate PPG signal and a perfusion index value to accommodate a variety of users and usage conditions. In some examples, the multiple light paths can include the same separation distances for noise cancellation due to artifacts resulting from, for example, tilt and / or pull of the device, a user's hair, a user's skin pigmentation, and / or motion. The PPG device can further include one or more lenses and / or reflectors to increase the signal strength and / or and to obscure the optical components and associated wiring from being visible to a user's eye.

Description

technical field [0001] The present invention relates generally to measuring photoplethysmographic (PPG) signals, and more particularly to an architecture for multiple optical paths and a masking method for PPG signals and perfusion index optimization. Background technique [0002] Photoplethysmographic (PPG) signals may be measured by the PPG system to derive corresponding physiological signals (eg, pulse rate). In basic form, a PPG system may employ a light source or light emitter to inject light into the user's tissue and a light detector to receive reflected and / or scattered light that exits the tissue. The received light includes light whose amplitude is modulated due to pulsatile blood flow (i.e., the "signal") and whose amplitude may be modulated (i.e., "noise" or "artifact") and / or unmodulated (i.e., , DC) parasitic, non-signal light. Noise may be introduced due to, for example, tilting and / or pulling of the device relative to the user's tissue, hair and / or motion. ...

AI Technical Summary

Problems solved by technology

That is, there is a trade-off that makes it difficult to optimize separation distance for specific user skin / tissue type and usage conditions

[0004] Additionally, a PPG system may include several light emitters, light detectors, components, and associated wiring that are visible to the user's eyes, making the PPG system unattractive

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