CPC A61B 5/681 (2013.01) [A44C 5/14 (2013.01); A61B 5/02427 (2013.01); A61B 5/02438 (2013.01); A61B 5/7203 (2013.01); G04G 21/025 (2013.01); A61B 5/02433 (2013.01); A61B 5/725 (2013.01)] | 20 Claims |
9. A system for non-invasive measurements of biomarkers, the system comprising:
a timekeeping device configured to be worn by a user;
a back case coupled to a body of the timekeeping device, the back case including a casing having a bottom wall and a side wall defining an inner space, a plurality of openings provided at the bottom wall, and an optoelectronic circuit board disposed in the inner space, the optoelectronic circuit board comprising:
a plurality of radiation sources arranged in selected ones of the plurality of openings provided at the bottom wall of the casing for illuminating radiation on the user's skin when the timekeeping device is worn by the user, each of the plurality of radiation sources having a different radiation emission wavelength to obtain a different degree of penetration into the user's skin; and
at least one radiation detector for detecting a reflected radiation signal exiting from the user's skin as a result of the radiation illuminated on the user's skin by the plurality of radiation sources and for generating a corresponding photoplethysmogram (PPG) signal, the at least one radiation detector being arranged in one of the plurality of openings other than the selected openings of the plurality of openings in which the plurality of radiation sources are arranged;
a band coupled to the body of the timekeeping device for mounting the timekeeping device around a wrist of the user so that the back case is in contact with the user's skin, the band comprising:
a flexible layer having adjusting elements for adjusting the band to the user's wrist;
coupling elements for coupling the flexible layer to the body of the timekeeping device;
a buckle coupled to an end of the flexible layer, the buckle having a frame and a pivoting prong coupled to the frame for selective engagement with the flexible layer adjusting elements; and
a tightening mechanism arranged in the frame of the buckle for obtaining a predefined adjustment of the band around the user's wrist to thereby increase the contact of the back case with the user's skin during illumination of the user's skin with the radiation by the plurality of radiation sources and detection of the reflected radiation signal by the at least one radiation detector, the tightening mechanism comprising a ratchet gear having locking teeth arranged at a periphery of the ratchet gear over a predetermined angular range, a pivoting strut configured for selective engagement with the locking teeth to place the tightening mechanism in a locked state, and a mechanism for pivoting the pivoting strut to disengage from the locking teeth to place the tightening mechanism in an unlocked state;
means for extracting epochs from the PPG signal generated by the at least one radiation detector;
means for identifying pulses of the extracted epochs; and
means for filtering the identified pulses until each pulse is within a predetermined reliability range.
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