Patent ID: 11937906
Assignee: ALIO, INC.
Field: Medical technology (Instruments)
Classification: CPC A | IPC A

Claim 0:
1. A system for monitoring blood flow metrics comprising:
a patch of a flexible substrate configured to attach to an area of skin over a blood vessel;
a plurality of light emitting diodes (LEDs) arranged on the substrate to form a R×C matrix and a row of C photodetectors (PDs) disposed on the substrate substantially in parallel with R rows of LEDs extending to form C columns substantially co-linear with each photodetector;
an optical signal interface mounted on the substrate and configured to drive each LED for an on-period and to input an optical signal at one of the photodetectors during the on-period to receive an intensity measurement for an optical path, OPrc, formed by LEDs in rows r=1 to R in columns c=1 to C and the photodetector receiving the optical signal;
a processing system comprising a memory for storing program instructions for execution by the processing system to:
determine an AC component, Irc,AC, and a DC component, Irc,DC, as a function of a plurality of intensity measurements, Irc, for each optical path, OPrc, over a period of time;
determine an AC-to-DC component ratio, R_(r,c)=I_(rc,AC)/I_(rc,DC), for each optical path;
determine a plurality of ratio-of-ratios, RoR values, by dividing a first plurality of selected AC-to-DC component ratios by a second plurality of selected AC to DC component ratios; and
using at least a subset of the RoR values to determine a biological metric;
where the processing system is configured to:
determine the plurality of RoRs by dividing AC to DC component ratios in each row of AC to DC component ratios by the AC to DC component ratios in a row of AC to DC component ratios corresponding to the optical paths for a nearest LED row nearest to the row of photodetectors.