# US 12,213,807 B2 · System and method for positioning a sensor on a subject > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,213,807 B2 - Document ID: US12213807B2 - Status: Granted - Kind: B2 - Application number: 17/817,321 - Filed: 2022-08-03 - Published: 2023-02-09 - Granted: 2025-02-04 - Earliest claimed: 2021-08-06 - Assignees: Rockley Photonics Limited - Applicants: Rockley Photonics Limited - Inventors: Benjamin Ver Steeg; Amit Singh Nagra; Haydn Frederick Jones - Web page: https://patentgrep.com/patent/US12213807B2 ## CPC - A61B 5/6835: {Supports or holders, e.g., articulated arms} - A61B 5/0075: {by spectroscopy, i.e. measuring spectra, e.g. Raman spectroscopy, infrared absorption spectroscopy (A61B5/0071 takes precedence)} - A61B 5/02416: {using photoplethysmograph signals, e.g. generated by infrared radiation (A61B5/14552 takes precedence)} - A61B 5/02427: {Details of sensor} - A61B 5/6833: {Adhesive patches} - A61B 5/7221: {Determining signal validity, reliability or quality (preventing, reducing or removing noise induced by motion artefacts A61B5/7207; noise originating from a therapeutic or surgical apparatus A61B5/7217)} - A61B 5/7235: {Details of waveform analysis (detecting specific parameters of the electrocardiograph cycle A61B5/349)} - A61B 5/7246: {using correlation, e.g. template matching or determination of similarity} - A61B 5/7278: {Artificial waveform generation or derivation, e.g. synthesizing signals from measured signals} - A61B 5/14532: {for measuring glucose, e.g. by tissue impedance measurement} - A61B 5/14546: {for measuring analytes not otherwise provided for, e.g. ions, cytochromes} - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) ## Abstract A system and method for positioning a sensor on a subject. In some embodiments, the system includes an instrument holder, the instrument holder being configured to be secured to a subject, and to hold an instrument temporarily. ## Claims ### Claim 1 A system, comprising: a sensor module comprising at least one of a spectrophotometer or a photoplethysmography sensor; a cap having a porous top; and an instrument holder configured to temporarily hold each of the sensor module and the cap, and comprising: a flexible fabric portion configured to be secured to a subject by an adhesive, and a rigid portion secured to the flexible fabric portion and comprising a socket defining an aperture, the socket comprising: a flat base secured to the flexible fabric portion; a plurality of straight walls that extend away from the flat base and that surround the aperture and form a plurality of internal corners of the aperture; and a detent comprising a plurality of rounded ribs or rounded recesses in the plurality of straight walls, the plurality of rounded ribs or rounded recesses being configured to hold the sensor module by engaging, via a snap fit, a corresponding plurality of rounded recesses or rounded ribs of the sensor module, and to hold the cap by engaging, via a snap fit, a corresponding plurality of rounded recesses or rounded ribs of the cap, wherein each of the plurality of rounded ribs or rounded recesses in the plurality of straight walls is spaced apart, along the plurality of straight walls, from both the flat base and a distal edge of the corresponding straight wall of the plurality of straight walls, the distal edge being distal to the flat base, wherein a horizontal cross section of the sensor module and a horizontal cross section of the aperture match, wherein the instrument holder is configured so that the sensor module contacts the skin of the subject when installed in the instrument holder, and wherein the instrument holder is configured such that, when the sensor module is held by the instrument holder, a maximum distance by which any portion of the sensor module is movable, relative to the instrument holder, in both translational directions along each of three orthogonal axes is 1 mm or less, and a maximum extent to which any portion of the sensor module is rotatable, relative to the instrument holder, in both rotational directions about each of the three orthogonal axes is 2.5 degrees or less. ### Claim 2 (depends on 1) The system of claim 1, wherein the sensor module comprises at least the spectrophotometer. ### Claim 3 (depends on 2) The system of claim 2, wherein the sensor module further comprises the photoplethysmography sensor. ### Claim 4 (depends on 1) A method for positioning the sensor module using the system of claim 1, the method comprising: holding, by the instrument holder, the sensor module on a first occasion; removing the sensor module from the instrument holder after the first occasion; holding, by the instrument holder, the sensor module on a second occasion after the removing the sensor module from the instrument holder; and calculating a repeatability metric based on a measurement obtained by the sensor module on the first occasion and a measurement obtained by the sensor module on the second occasion. ### Claim 5 (depends on 4) The method of claim 4, wherein the calculating of the repeatability metric comprises calculating a difference between a peak-to-trough measurement obtained on the first occasion and a peak-to-trough measurement obtained on the second occasion, each of the peak-to-trough measurements being a difference between a maximum measured value and a minimum measured value. ### Claim 6 (depends on 5) The method of claim 5, wherein: the sensor module comprises the spectrophotometer, and the peak-to-trough measurement obtained on the first occasion is the difference between: a maximum reading, over wavelength, obtained by the spectrophotometer, and a minimum reading, over wavelength, obtained by the spectrophotometer. ### Claim 7 (depends on 4) The method of claim 4, wherein: the sensor module comprises the spectrophotometer; the measurement obtained by the sensor module on the first occasion comprises a first vector of spectral samples; the measurement obtained by the sensor module on the second occasion comprises a second vector of spectral samples; the calculating of the repeatability metric comprises calculating a distance between a first vector of scalar projections and a second vector of scalar projections; each element of the first vector of scalar projections is a scalar projection of the first vector of spectral samples onto a corresponding loading vector of a plurality of loading vectors; and each element of the second vector of scalar projections is a scalar projection of the second vector of spectral samples onto a corresponding loading vector of the plurality of loading vectors. ### Claim 8 (depends on 7) The method of claim 7, wherein the distance is a Mahalanobis distance. ### Claim 9 (depends on 7) The method of claim 7, wherein the distance is a Euclidean distance.