Physiological monitoring system for measuring blood oxygen concentration

Abstract

The invention relates to a physiological monitoring system for measuring blood oxygen concentration. A wearable device is described. The wearable device includes a housing having a back cover and an optical shield on a first portion of the back cover. The back cover includes a set of windows, where a first subset of windows of the set of windows is defined by a second portion of the back cover that is free of the optical shield thereon, and a second subset of windows of the set of windows is inserted into a set of openings in the back cover. An optical barrier surrounds each window of the second subset of windows. A set of light emitters is configured to emit light through at least some of the set of windows. A set of light detectors is configured to receive light passing through at least some of the set of windows.

Description

[0001] This divisional application is a divisional application of the invention patent application with the international application number PCT / US2020 / 051866, the international filing date of September 21, 2020, which entered the Chinese national phase on September 17, 2021, with the application number 202080022116.9 and the invention title "Physiological Monitoring System for Measuring Blood Oxygen Concentration".

[0002] Cross - Reference to Related Applications

[0003] This Patent Cooperation Treaty patent application claims the priority of U.S. Provisional Patent Application No. 62 / 907445 filed on September 27, 2019 and U.S. Non-Provisional Patent Application No. 17 / 018850 filed on September 11, 2020, the entire contents of which are incorporated herein by reference. Technical Field

[0004] Some of the described embodiments generally relate to physiological monitoring systems for measuring blood oxygen concentration, and more particularly to reflective devices and systems for measuring blood oxygen concentration. Some of the described embodiments also relate to or alternatively relate to emitting and receiving light through the housing of a wearable device. Background Art

[0005] The use of technologies for monitoring a user's heart rate or other types of biometric information has increased in the medical community and among the general public with the advancement of sensing technologies. In some examples, a sensing device (e.g., a chest strap heart rate monitor or a watch) may be able to measure a person's heart rate while the person is engaged in a physical activity such as running, and may alert the user when the heart rate changes outside of a desired range.

[0006] In some cases, sensing devices can be used for pulse oximetry, which can be an effective and rapid way to monitor a person's cardiopulmonary function. Since the amount of oxygen carried by hemoglobin can affect the color of the blood, these pulse oximetry devices may be able to assess the color of the blood. In some examples, a pulse oximetry device can be placed on a person's finger to measure oxygenation in the person's blood. Generally, these device measurements can be reliable because the small tissue area on which the device measures the person is homogeneous in nature. Summary of the Invention

[0007] Embodiments of the systems, devices, methods, and apparatuses described in this disclosure relate to a wearable device for pulse oximetry. Also described are systems, devices, methods, and apparatuses for a wearable device having a set of openings and a set of protrusions adjacent to the set of openings. The wearable device may include a set of windows in such openings and adjacent to the set of protrusions. The wearable device may include a light detector that can receive light through one of the windows of the set of windows. The protrusions and materials around the perimeter of such windows may at least partially serve as a barrier to unwanted light detected by such sensors, as such windows may be at least partially isolated from unwanted light sensed by such sensors.

[0008] In some examples, this disclosure describes a wearable device that may include a housing having a back cover and an optical shield (e.g., at least one of an ink, film, coating, or surface treatment) on a number of first portions of the back cover. The back cover may include a set of windows, where a first subset of windows of the set is defined by a second portion of the back cover that does not have the optical shield thereon, and a second subset of windows of the set is inserted into a set of openings in the back cover. An optical barrier may surround each window in the second subset of windows. A set of light emitters may be configured to emit light through at least some of the windows of the set. A set of light detectors may be configured to receive light through at least some of the windows of the set.

[0009] In some examples, this disclosure describes a wearable device that may include a first set of emitters, a second set of emitters, and a set of detectors, the first set of emitters being configured to emit wavelengths in a red light range, the second set of emitters being configured to emit wavelengths in an infrared light range. Each detector in the set of detectors may be configured to detect amounts of at least the red light range wavelengths and the infrared light range wavelengths. The wearable device may also include a processor configured to: operate the first set of emitters and the second set of emitters; receive an indication of such amounts of at least the red light range wavelengths and the infrared light range wavelengths detected by the set of detectors; and determine an oxygenation level using at least a subset of such indications.

[0010] In some examples, this disclosure describes a wearable device that may include a housing, a display, and a skin-facing cover, the display viewable through a front side of the housing, the skin-facing cover on a back side of the housing. The skin-facing cover may have an inner surface, an outer surface, and a set of protrusions adjacent to a set of openings. The set of openings may extend through the skin-facing cover from the inner surface to the outer surface of the skin-facing cover. The wearable device may also include a set of windows and a set of light detectors, the set of windows disposed in the set of openings and adjacent to the set of protrusions, the set of light detectors disposed within the housing and configured to receive light through the set of windows.

[0011] In some examples, the present disclosure describes a wearable device. The wearable device may include a skin-side cover. The skin-side cover may include: an inner surface; an outer surface; and a set of protrusions adjacent to a set of openings that extend through the inner surface and the outer surface; a set of windows disposed in such openings and adjacent to the set of protrusions; and a light detector configured to receive light passing through one of the windows in the set of windows. In some examples, the skin-side cover may be optically opaque. In some examples, the set of protrusions may include a stepped protrusion and / or the set of protrusions may include a tapered protrusion. In some examples, the skin-side cover may be optically transparent and the set of windows may be optically transparent. In some examples, one or more of the protrusions in the set of protrusions may be coated with an optically opaque material, where the optically opaque material may be an optically opaque ink. In some examples, one or more of the protrusions of one or more of the windows in the set of windows may be coated with an optically opaque material.

[0012] In yet further examples, the light detector may be a first light detector, and the window may be a first window, and the wearable device may further include: a second light detector configured to receive light passing through a second window in the set of windows; a first light emitter configured to emit light through a third window in the set of windows, where the third window is closer to the first window than the second window; and each of the first light detector and the second light detector is configured to receive the reflection or backscattering of the light emitted by the first light emitter. In some examples, the wearable device may further include a second light emitter configured to emit light through a fourth window in the set of windows, where each of the first light detector and the second light detector is configured to receive the reflection or backscattering of the light emitted by the second light emitter. In some examples, the first light emitter may be configured to emit red light, where each of the windows in the set of windows is optically transparent to at least red light and wavelengths in the infrared range; and each of the protrusions in the set of protrusions extends from an edge of one of such openings in a generally direction parallel to a plane of the inner surface, and each opening has a smaller diameter at the inner surface than at the outer surface. In some examples, each of the windows in the set of windows may be circular in shape.

[0013] In some examples, the present disclosure describes a reflective sensing device that may include: a first transmitter configured to emit a wavelength in a red light range; a second transmitter configured to emit a wavelength in an infrared light range; a first detector; a second detector, wherein both the first detector and the second detector are configured to detect at least the wavelength in the red light range emitted by the first transmitter and the wavelength in the infrared light range emitted by the second transmitter; and a processor configured to receive indicators of the amounts of the detected wavelength in the red light range and the detected wavelength in the infrared light range received from the first detector and the second detector respectively, the processor further configured to determine a degree of oxygenation using at least a subset of such indicators. In some examples, the first detector may detect such red light wavelengths emitted by the first transmitter on a first optical path, and the second detector may detect such red light wavelengths emitted by the first transmitter on a second optical path, and the first optical path and the second optical path may be of different lengths. In some examples, the reflective sensing device may further include: a third transmitter configured to emit a wavelength in a green light range; and a third detector configured to detect at least the emitted wavelength in the green light range from the third transmitter, wherein the processor is configured to receive the detected wavelength in the green light range from at least the third detector. In some examples, the processor may be configured to sum the indicators of the amounts of the detected wavelength ranges from the first detector, the second detector, and the third detector. In some examples, the first transmitter, the second transmitter, and the third transmitter may emit light sequentially. In some examples, the processor may be configured to determine the subset of the received red light and infrared light for the determined degree of oxygenation at least in part based on the received green light.

[0014] In some examples, the present disclosure describes a wearable device that may include: a back cover including a set of windows disposed around a central portion of the back cover; a set of light emitters disposed below a first subset of the set of windows included in the back cover, the set of light emitters configured to emit at least red light and infrared light; a set of light detectors disposed below a second subset of the set of windows included in the back cover, the set of light detectors configured to detect at least the red light and the infrared light emitted by the set of light emitters. In some examples, the set of windows may be adjacent to a set of protrusions that extend adjacent to a set of openings through the back cover. In some examples, the distance of at least a first window of the first subset of windows from the second subset of the set of windows may be different from the distance of a second window of the first subset of windows from the second subset of the set of windows.

[0015] In some examples, the present disclosure describes a reflective sensing device that may include: a housing having a back cover; a set of transmitters disposed within the housing and may include: a first subset of transmitters configured to emit red light through the back cover; and a second subset of transmitters configured to emit infrared light through the back cover; a set of detectors disposed within the housing and configured to detect the red light received through the back cover and the infrared light received through the back cover; a set of optical barriers that form part of the back cover and extend through the back cover, the set of optical barriers being configured to block the emitted light from impinging on the set of detectors before the light emitted by the set of transmitters passes through an outer surface of the back cover.

[0016] In some examples, the reflective sensing device may further include: a processor configured to determine a degree of oxygenation of a user of the reflective sensing device, wherein the degree of oxygenation is determined using the amounts of reflected red light and reflected infrared light detected by the set of detectors. In some examples, the set of optical barriers may define an optically closed wall around at least one of a set of openings in the back cover, wherein such openings extend through the back cover. In some examples, the set of optical barriers may include hollow sleeves disposed in the set of openings of the back cover of a wearable device. In some examples, at least one transmitter may be positioned to emit light within an opening defined by one of such hollow sleeves. In some examples, at least one detector of the set of detectors may be positioned to receive light passing through an opening defined by one of such hollow sleeves, and / or at least one of such hollow sleeves may have an outer perimeter wall coated with an opaque material. In some examples, the opaque material may be an opaque ink.

[0017] In yet further examples, at least one of such hollow sleeves may have an inner perimeter wall coated with an opaque material. In some examples, the reflective sensing device may further include a set of windows disposed in the set of openings of the back cover. In some examples, the set of windows may be optically transparent windows. In some examples, the back cover may be an optically transparent back cover. Additionally, in some examples, the set of optical barriers may reflect at least the red light range of wavelengths and may reflect at least the infrared light range of wavelengths. In some examples, the set of optical barriers may be optically opaque. In some examples, the set of optical barriers includes black glass.

[0018] In some examples, the present disclosure describes a wearable device that may include: a back cover having: a substrate that defines a portion of an inner surface and an outer surface of the wearable device; and a set of frit that extends through the substrate from the inner surface to the outer surface of the substrate and defines a portion of the outer surface of the back cover, wherein such frit of the set of frit has frit openings that extend through the inner surface and the outer surface; a set of windows that are disposed in such frit openings and define a portion of the outer surface of the back cover; and a set of light detectors that are disposed to receive light through a subset of the windows of the set of windows. In some examples, the subset of windows may be a first subset of windows; and the set of windows may further include a second subset of windows of the set of windows; and the wearable device may further include a set of emitters configured to emit light through the second subset of windows. In some examples, the back cover and the set of windows may be optically transparent. In some examples, at least one window of the set of windows has an outer diameter wall coated with an optically opaque material.

[0019] In some examples, the present disclosure describes a method of forming an optical barrier in a reflective sensing device that may include: inserting a hollow cylinder into a back cover opening of a wearable device, wherein the hollow cylinder has a centrally located opening; welding the hollow cylinder to the back cover to form a mechanical bond between the materials of the hollow cylinder and the back cover; inserting an optically transparent window into the centrally located opening of the hollow cylinder; and welding the optically transparent window to the hollow cylinder to form a mechanical bond between the materials of the hollow cylinder and the optically transparent window, wherein: the hollow cylinder may be an optically opaque material and may form an optical barrier between light emitted by an emitter configured to emit light through the back cover and a detector that is configured to receive light through the back cover and is positioned on the same side of the back cover as the emitter. In some examples, the optically opaque material includes black glass. In some examples, each of the back cover and such windows may be sapphire.

[0020] In some examples, the present disclosure describes a reflective sensing device that may include: a housing; a first set of emitters configured to emit infrared light through the housing; a second set of emitters configured to emit red light through the housing; a first set of waveguides configured to direct the infrared light emitted by the first set of emitters toward the housing; a second set of waveguides configured to direct the red light emitted by the second set of emitters toward the housing; a set of detectors configured to detect the reflection or backscattering of the infrared light emitted by the first set of emitters and the red light emitted by the second set of emitters; and a processor configured to determine a degree of oxygenation of a user of the reflective sensing device, wherein the degree of oxygenation is determined using the amounts of reflected or backscattered red light and reflected or backscattered infrared light detected by the set of detectors. In some examples, the first set of waveguides may internally reflect infrared light, and / or the second set of waveguides may internally reflect red light. In some examples, the first set of waveguides and the second set of waveguides may be solid materials, and / or the core of the solid material may internally reflect infrared light and red light.

[0021] In some examples, the reflective sensing device may further include: a set of windows, where the set of windows may include: four emitter windows configured to allow the infrared light and red light emitted by the first set of emitters and the second set of emitters to pass through such emitter windows; and four detector windows configured to allow the reflected infrared light and the reflected red light to pass through the four detector windows and reach the set of detectors. In some examples, the reflective sensing device may further include: a third set of emitters configured to emit green light; a third set of waveguides configured to direct the green light to a third set of the set of windows; and the set of detectors further configured to detect the reflected or backscattered green light emitted by the third set of emitters.

[0022] In some examples, the present disclosure describes a wearable device that may include: a back cover; a set of emitters configured to emit light; a first set of waveguides optically coupled to the set of emitters and configured to direct the emitted light through the back cover; and a photodetector of a set of photodetectors arranged to receive the reflected or backscattered light emitted by the set of emitters. In some examples, at least a first waveguide of the first set of waveguides may be configured to direct light from a first set of the set of emitters, where the first set of emitters may be configured to emit red light. In some examples, at least a second waveguide of the first set of waveguides may be configured to direct light from a second set of the set of emitters, where the second set of emitters may be configured to emit infrared light.

[0023] In yet a further example, the wearable device may further include: a second set of waveguides that may be configured to receive the reflected red light and the reflected infrared light. In some examples, the second set of waveguides may be configured to direct the light to the set of detectors. In some examples, the first set of waveguides and the second set of waveguides may be hardened glass. In some examples, the second set of waveguides may internally reflect infrared light and red light. In some examples, the first set of waveguides may internally reflect red light and may internally reflect infrared light. In some examples, the wearable device may further include: a third set of emitters of the set of emitters, the third set of emitters being configured to emit green light, wherein the first set of waveguides and the second set of waveguides may internally reflect green light. In some examples, the first set of waveguides and the second set of waveguides may be fiber optic waveguides.

[0024] In some examples, the present disclosure describes a reflective sensing device that may include: a first emitter configured to emit a wavelength in a red light range; a second emitter configured to emit a wavelength in an infrared light range; a first detector; a second detector, wherein both the first detector and the second detector are configured to detect at least the reflected red light range wavelength from the first emitter and on a first optical path, and both the first detector and the second detector are configured to detect at least the reflected infrared light range wavelength from the second emitter and on a second optical path, wherein the first optical path and the second optical path may be of different lengths. In some examples, the reflective sensing device may further include: a first waveguide configured to direct the emitted red light wavelength; and a second waveguide configured to direct the emitted infrared light wavelength. In some examples, the detected red light and infrared light range wavelengths may be detected on a first optical path and a second optical path of different lengths, such red light and infrared light range wavelengths providing a map of arterial or venous blood flow for pulse oximetry.

[0025] In addition to the above-described exemplary aspects and embodiments, further aspects and embodiments will become apparent by reference to the drawings of the specification and by study of the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present disclosure may be more readily understood by reference to the following detailed description in conjunction with the accompanying drawings, in which like reference numerals refer to like structural components, and in which:

[0027] Figure 1A An example of a wearable device is shown;

[0028] Figure 1B An example of a wearable device is shown;

[0029] Figure 2 An example layout of emitters and detectors is shown;

[0030] Figure 3 Shows an example layout of a transmitter and a detector;

[0031] Figure 4 Shows an example layout of a transmitter and a detector;

[0032] Figure 5A Shows an example of the back side of a wearable device;

[0033] Figure 5B Shows an example of the back cover of a wearable device from a side view;

[0034] Figure 5C Shows an example of the back cover of a wearable device;

[0035] Figure 5D Shows an example of the back cover of a wearable device from a side view;

[0036] Figure 6A Shows an example of the back side of a wearable device;

[0037] Figure 6B Shows an example of the back cover of a wearable device from a side view;

[0038] Figure 6C Shows an example of the back cover of a wearable device;

[0039] Figure 7 Shows an example of the back cover, transmitter, detector, and waveguide of a wearable device from a side view;

[0040] Figure 8A Shows an example of the back cover of a wearable device;

[0041] Figure 8B Shows an example of the back cover of a wearable device;

[0042] Figure 8C Shows an example of the back cover of a wearable device;

[0043] Figure 8D Shows an example of the back cover of a wearable device;

[0044] Figure 9A Shows the layout of the back cover of a wearable device;

[0045] Figure 9B Shows the layout of the back cover of a wearable device; and

[0046] Figure 10 Shows a sample electrical block diagram of an electronic device.

[0047] The cross-hatching or shading used in the drawings generally serves to clarify the boundaries between adjacent components and also aids in the identification of the drawing figures of the specification. Accordingly, the presence or absence of cross-hatching or shading is not intended to express or indicate a preference or requirement for any particular material, material property, component ratio, component size, generality of similarly shown components, or any other characteristic, attribute, or property of any component shown in the drawings.

[0048] In addition, it should be understood that the proportions and dimensions (relative or absolute) of the various features and components (and their assemblies and groups) and the boundaries, distances, and positional relationships presented therebetween are provided in the drawings only to facilitate an understanding of the various embodiments described herein and, accordingly, may not necessarily be presented or shown to scale and are not intended to indicate any preference or requirement for the embodiments shown to exclude reference to the embodiments described thereof. DETAILED DESCRIPTION

[0049] Reference will now be made in detail to representative embodiments shown in the drawings. It should be understood that the following description is not intended to limit the embodiments to one preferred embodiment. On the contrary, it is intended to cover various alternatives, modifications, and equivalents that may be included within the spirit and scope of the described embodiments as defined by the appended claims.

[0050] Typically, different types of biometric information (such as heart rate and / or degree of blood oxygenation) can be monitored for a person. Sensing devices that do not require invasive procedures on the person can be used to monitor biometric information. Sensing devices can be used to monitor this information, such as a thermometer that can be placed in a person's ear or on the forehead, or a heart rate and / or blood oxygenation device that can be placed on a person's index finger. A characteristic of these devices is that they are of the pass-through measurement type. When using these devices, light can be emitted onto one side of a finger or earlobe, and the light can be detected on the other side of the finger or earlobe. Before the light is detected, the light generally penetrates through about 0.5 cm to 1.0 cm of tissue. These sensing devices can be effectively used in a controlled environment, for example, during a medical examination. To measure a person's degree of blood oxygenation, a sensing device (such as a pulse oximeter) can be placed on the person's index finger. The pulse oximeter can measure changes in the color of the blood in a small tissue area, and thus a single emitter and a single detector can be used. Further, because a small tissue area is measured, the tissue in the small area (such as the index finger or earlobe) may be relatively homogeneous, which can make the measured value reasonably reliable. The index finger or earlobe can be a restricted area and an area rich in tissue, which can additionally make the measured value reasonably reliable. Further, the fingertip is rich in blood vessels and generally provides a strong pulsating light signal for pulse oximetry, which can also contribute to a reasonably reliable measured value. Although these techniques can provide accurate measured values, these devices are not conducive to performing measurements when the user is moving or engaged in daily activities. Therefore, sensing devices (such as heart rate monitors) are integrated into wearable devices so that a person can monitor biometric data (such as heart rate) every day and simultaneously engage in various activities.

[0051] Some heart rate monitors are incorporated into human wearables such as chest straps, watches, and other types of fitness bands that monitor biometric data during daily activities or monitor and / or maximize performance during exercise, training, and / or competition. Additionally, in cases where the device is worn on the wrist or strapped to the user's chest or forehead or elsewhere, tissue depth or structures within the tissue can significantly limit the amount of light passing through and exiting the tissue. Sensors such as heart rate monitors or pulse oximeters can thus be configured as reflective devices that emit light into one side of the wrist or limb and receive the reflection of the light through the same side of the wrist or limb. Additionally, in cases where the device is attached to the user via a band, it may be useful to implement the biometric sensor system as a reflective sensor to avoid the need to incorporate parts of the sensor system into the device's band (which may be necessary if the sensor system is implemented as a transmissive or penetrative type sensor system). Because these sensing devices can be integrated into devices such as wristbands, watches, and smartwatches, different difficulties can arise due to the heterogeneous nature of the tissue in a person's wrist. For example, wrist tissue can include a dense network of blood vessels, tendons, ligaments, and bones, all or some of which can reflect, scatter, and / or absorb light, thus making measurements at the wrist difficult.

[0052] Alternatively and as discussed herein, measurements can be implemented in an improved manner, thus improving the accuracy and reliability of the measurements. In some examples, the sensing device can be a wearable device such as a watch or smartwatch that can be worn on a person's wrist. The watch can include multiple transmitters and multiple detectors to image and / or optically probe the wrist tissue, which can address the heterogeneous nature of the wrist tissue and provide accurate measurements by collecting light passing through multiple regions. Further, the watch can include multiple transmitters and multiple detectors to sample the light that has passed through multiple tissue regions, which can address the reduced vascular density and heterogeneous nature of the wrist tissue. By utilizing multiple transmitters and detectors, different lengths of light paths can propagate through the tissue, and it can be ensured that the light travels through the tissue rather than simply reflecting off the tissue surface. In some less desirable cases, if the device attached to the user's band is loose, tilted, or deliberately worn loosely, the light may reflect off the tissue surface. The multiple transmitters and multiple detectors can provide sufficient data such that the processor may be able to identify false readings and invalid or useless measurements from the data. In some examples, the signals from the detectors (e.g., indicators of the amount of detected light) can be summed before processing, and in some cases, regions suspected of data corruption can be excluded. Corrupted data may result from crosstalk and / or excessive tissue heterogeneity caused by the watch being lifted away from the user's skin.

[0053] To enable the light from the emitter to reach the human wrist tissue, a window can be provided on the inner side or the skin-facing side of the wearable device. The window can also provide an aperture through which the light reflected and / or backscattered from the wrist tissue can be detected by the detector. The window can be anchored in the back cover and can be characterized by the one or more wavelengths of electromagnetic radiation that can pass through it. Further, the window can be disposed in an opening extending through the back cover, and in some examples, the window can be a sapphire window. These windows can be anchored to the skin-facing side of the wearable device in various ways that will be discussed in further detail herein, and in some cases, can be mounted in or on a back cover also formed of sapphire. Further, the method for fixing the window in the back cover of the wearable device can also include an optical isolation method to reduce and / or eliminate internal crosstalk between the emitter and the detector.

[0054] In some examples, light can be emitted to reach the user's wrist tissue via a waveguide. The waveguide can direct the emitted light through the skin-side cover or the back cover and to the wrist tissue. Similarly, the reflected light can be received or detected via a waveguide that can direct the reflected light to one or more detectors. The waveguide can direct the light through a window that can be anchored in the back cover and / or receive the reflected light passing through such a window. Alternatively, the waveguide can directly direct the light through the back cover and / or receive the reflected light passing through the back cover via an opening in the back cover, where there may be no window in the back cover. The opening in the back cover can extend through the inner surface and the outer surface of the back cover.

[0055] This document describes various configurations for maximizing the use of the emitter and the detector for pulse oximetry. In some embodiments, the window can be fixed by a method that provides an optical barrier between the emitter and the detector.

[0056] Reference Figures 1A to 10 These and other embodiments are discussed below. However, those skilled in the art will understand that the detailed descriptions given herein with respect to these figures are for illustrative purposes only and should not be construed as limiting.

[0057] Directional terms such as "top", "bottom", "upper", "lower", "above", "below", "beneath", "front", "back", "over", "under", "left", "right", etc. are used with reference to the orientation of some components in some of the specification drawings described below. Since the components in various embodiments can be positioned in many different orientations, the directional terms are for illustrative purposes only and in no way limit. The directional terms are intended to be interpreted broadly and should not be construed to exclude components oriented in different ways.

[0058] Figure 1A An example of the wearable device 100 is shown. In some examples, the wearable device 100 may be configured to perform a number of biometric or physiological measurements of the user or a person who may wear the wearable device 100. In Figure 1A an example, the wearable device 100 may include a reflectance sensing device configured to perform pulse oximetry on a user wearing the wearable device 100.

[0059] Figure 1A An example of the wearable device 100 having a front side 105 and a back side 110 is depicted. The wearable device can be worn on a user's wrist and can be any type of watch (e.g., a smartwatch or a sports watch), or any type of biometric device, such as a heart rate monitor. The back side 110 of the wearable device 100 will be discussed in further detail herein. In an alternative embodiment, the wearable device can be configured to be worn on an arm, head, neck, thigh, torso, or other body part.

[0060] The user of the wearable device 100 can view the display of the wearable device 100 through the front side 105 of the wearable device 100. The display can be configured to display information such as time, date, weather, etc. The display can also be configured to display biometric measurement values or data (e.g., the user's heart rate or degree of oxygenation) obtained by the reflectance sensing device, which is at least partially visible on the back side 110 of the wearable device 100. The back side 110 of the wearable device 100 can be the skin-facing side that can be adjacent to the skin of the user wearing the wearable device 100. In some examples, the back side 110 of the wearable device may or may not be in direct contact with the skin of the user wearing the wearable device 100. The back side 110 will be discussed in further detail herein.

[0061] In some examples, the wearable device 100 can be a watch and a biometric measurement device. The wearable device 100 can be configured to measure various biometric user data of the user wearing the wearable device 100, such as heart rate and degree of oxygenation. Since the wearable device 100 can be worn on the user's wrist, factors different from other types of biometric sensors or detectors can be taken into account.

[0062] The design of biometric sensors can consider various factors, such as whether to use optical or electrical sensors, ease of use, the possible usage environment of the sensors, battery and / or power consumption, measurement accuracy, the wavelength of the emitter, the size and form factor of the detector or sensor, any combination thereof, etc. The terms detector and sensor may be used interchangeably herein. Some biometric sensors can measure heart rate via a chest strap that may include two electrodes. The electrodes on the chest strap can contact the skin to measure the user's heart rate. Due to the user's dynamic movement and the various environments and body conditions in which the chest strap may be used, such as extremely cold weather, very hot weather, sweat, salt water, chlorinated water, etc., electrical sensors can be used for the chest strap. Although the chest strap can be bulky, an additional component that the user must wear, and may have a limited battery life, the ability to make accurate measurements in multiple environments while performing dynamic movement may be more important than the inconvenience of wearing the chest strap.

[0063] Other biometric sensors used by medical professionals can be used on and / or worn on the user's finger, or in some cases, on the user's ear or earlobe. Biometric sensors (such as thermometers and pulse oximeters) can be configured to be used in a small body area of a body part having blood vessels (such as veins, arteries, and microvessels close to the skin surface), such as on the index finger or in or on the ear. When detecting heart rate or blood oxygen level, the proximity of the blood vessels in the finger to the skin surface can facilitate accurate measurement. Additionally, because the small tissue areas used are on the fingertips or in the ears, these biometric sensors can be useful in a controlled environment, but not so useful when performing daily activities. Further, the small areas of the fingertips or earlobes can provide homogeneous tissue for the sensors, thus allowing accurate data to be measured when making measurements in a small area.

[0064] A pulse oximeter may be able to measure the color of a person's blood and generally provides a quick and accurate way to monitor a person's heart and / or lung function. The color of a person's blood can change as the oxygen concentration in the person's blood changes. When the color of a person's blood changes, the pulse oximeter can detect or sense the change. Since the pulse oximeter used on the fingertip or ear measures a small area, the sensing device can use a single light source or emitter and a single detector for each corresponding wavelength. For example, these pulse oximeters can use a light source that emits red light and a light source that emits infrared light, and can use a single detector capable of sensing both red light and infrared light to sense the emitted light.

[0065] In Figure 1AIn [description], the wearable device 100 can be worn on the user's wrist, and since pulse oximetry is performed by the wearable device 100 having a transmitter and a detector on the wrist, the measurement may become more complex. Generally, the wrist tissue in the area where a watch is typically worn on the wrist is heterogeneous and may have different vascular densities from the fingertips or earlobes or ears. The wrist can have bones, tendons, veins, and arteries, and the light from the sensor can be reflected from them, which may provide unpredictable results and may provide incorrect measurement values in some cases. Additionally, the wrist area where the measurement can be performed is a larger area than the fingertips or earlobes, so more data can be provided, some of which may not be accurate data.

[0066] Figure 1B Shows an example of the wearable device 100. Similar to Figure 1A , the wearable device 100 can include a reflectance sensing device configured to perform pulse oximetry on a user wearing the wearable device 100. Figure 1B Depicts an example of the dorsal side 110 of the wearable device 100 shown in Figure 1A . In some examples, Figure 1B The wearable device 100 having a front side 105 (as shown in Figure 1A ) and a dorsal side 110 can be worn on the user's wrist and can be any type of watch (e.g., a smartwatch or a sports watch), or any type of biometric measurement device, e.g., a heart rate monitor.

[0067] In Figure 1B , the wearable device 100 includes a back cover 107 or a skin side cover member that forms part of the housing of the wearable device 100. The wearable device 100 also includes a window 120 in the back cover 107, which in some examples can be visible on the outer surface of the wearable device 100 facing the skin side. The back cover 107 and / or the window 120 can be formed of sapphire, glass, plastic, or other materials. In some embodiments, some or all of the window 120 can be a sapphire window mounted (i.e., inserted) in an opening in the sapphire back cover 107. Some or all of the windows can also be integrated with the back cover 107 and be defined by other portions of the back cover 107 where there is no optical shielding (e.g., ink (optically opaque ink), film, coating, or surface treatment). For example, the optical shielding can be on a first portion (e.g., non-window portion) of the back cover 107 and not present on a second portion of the back cover 107. Some windows 120 can provide an aperture through which the transmitter of the reflectance sensor system (not shown in Figure 1B ) can emit light. The emitted light can be transmitted into the user's tissue and then scattered, absorbed, or reflected away by the user's tendons, bones, and blood vessels. The light reflected from arterial blood can be received by the reflectance sensor system incorporated in the wearable device 100 (not shown inFigure 1B Detected by the detector in (). Some windows 120 may provide an aperture through which a detector (i.e., a light detector or a photodetector) can detect the self-organized reflected light. The window 120 can provide good coupling between the window 120 and the skin, which can ensure acceptable measurement accuracy. Further, the window 120 can provide optical isolation of the reflected light, and the method of providing this optical isolation is discussed in further detail herein. In some embodiments, the window 120 above the emitter can be integrated with the back cover 107, and the window 120 above the detector can be inserted into the back cover 107.

[0068] In some examples, the outer surface of the dorsal side 110 of the wearable device 100 can be in close contact with the user's wrist, which can reduce the air gap between the window 120 and the user's tissue. The air gap may reduce the accuracy of the detector because the tilt of the wearable device 100 causes it to be in contact with the skin in some places but not in others, so some of the light reflected from the tissue may pass through the air while some of the reflected light may not, thus changing the optical path to the detector and potentially affecting the detector reading. Alternatively, the wearable device 100 may be in close contact with the user's tissue and may be too tight, thus restricting the user's blood flow and affecting the detector reading. As discussed herein, multiple emitters and multiple detectors can be used to provide a blood oxygenation measurement. When using more than one emitter and detector, there can be multiple different optical path lengths and optical path directions between the emitter and the detector. These multiple optical path lengths and optical path directions can be utilized to compensate for air gaps, etc., by selecting the appropriate (multiple) paths that can provide meaningful information for determining the degree of blood oxygenation.

[0069] Figure 2 An example layout 200 of the emitter and the detector is shown. In some examples, the layout 200 of the emitter and the detector can be incorporated into some aspects of the wearable device 100, as referenced Figure 1A and Figure 1B as described. In the example of Figure 2 , the layout 200 of the emitter and the detector can be included in the wearable device to provide physiological measurements and / or biometric measurements of the user of the wearable device 100 for Figure 1A and Figure 1B .

[0070] By way of example and for illustrative purposes, the layout 200 of the emitter and the detector can be positioned on the skin-facing side of the wearable device 100, as referenced Figure 1A and Figure 1B as discussed. The layout 200 of the emitter and the detector can be provided by a back cover or a skin-side cover member having a window or an aperture (not shown in Figure 2is protected, which is further discussed in detail herein.

[0071] As Figure 2 shown, the layout 200 may include emitters (e.g., emitters 205a to 205c positioned within emitter window 205) positioned within various emitter windows 205, 210, 215, and 220. Figure 2 Also shown are detectors 225a, detector 235a, detector 240a, and detector 250a. Emitters 205a to 205c may include a green light emitter 205a, an infrared light emitter 205b, and a red light emitter 205c. Similarly, each group of emitters positioned within the other emitter windows 210, 215, and 220 may include a green light emitter, an infrared light emitter, and a red light emitter. Although green light, infrared light, and red light may be described herein as being emitted by the emitters, green light may be understood as electromagnetic radiation within an approximate range of green light wavelengths, infrared light may be electromagnetic radiation within an approximate range of infrared light wavelengths, and red light may be electromagnetic radiation within an approximate range of red light wavelengths. In some examples, the emitters may be coherent light sources (such as lasers and / or laser diodes), semi-coherent light sources (such as light emitting diodes or superluminescent diodes), incoherent light sources, or any other suitable light emitting sources. Additionally depicted in Figure 2 the respective individual emitters and detectors (or light detectors) may receive power and / or communicate via bond wires.

[0072] Figure 2 Detectors 225a, 235a, 240a, and 250a of windows 225, 235, 240, and 250 of may be electromagnetic radiation detectors. The terms detector and sensor may be used interchangeably herein. Figure 2 Each of the detectors in may be configured to receive any light emitted by any one of the emitters in emitter windows 205, 210, 215, and / or 220. Detectors 225a, 235a, 240a, and 250a may be configured to detect or receive light or photons and convert the detected light / photons into an electric current and / or an electrical signal. Depending on the position of the emitter from which the detector receives light, the detected light may have a varying magnitude due to various light scattering, absorption, and / or reflection caused by wrist tissue and may be more or less easily detected by the detector.

[0073] Detectors 225a, 235a, 240a, and 250a may detect by Figure 2Any of the emitted green light, infrared light, and / or red light emitted by the emitter in Figure 2 Detector 225a of

[0074] can be Figure 2 The emitters 205a to 205c and detectors 225a, 235a, 240a, and 250a of the emitter windows 205, 210, 215, and 220 in the layout 200 of Figure 2 are arranged in a ring around the central portion of the back cover or skin side cover of the wearable device or watch. As shown in the example of Figure 2In the example, by arranging the emitter and the detector in a ring around the central region, the coverage area can be increased with fewer components. Due to the complexity of imaging and / or optically detecting heterogeneous tissues, in addition to maximizing the distance between the emitter and the detector, other factors may be considered for the emitter and detector layout, such as false readings, emitter light clipping, path or channel length, battery life, power consumption, any combination thereof, etc. These factors are discussed in further detail herein.

[0075] As Figure 2 shown, the layout 200 can be configured to accommodate eight windows, which may include four emitters and four detectors for measuring pulse oximetry. Although four emitters and four detectors may be discussed herein, in some examples, six windows (which may include three emitters and three detectors) can be used to fit the size of the watch. Any suitable number of multiple emitters and multiple detectors can be used for pulse oximetry as long as the configuration and number of the emitters and detectors can be integrated into the wearable device. In some examples, using four emitters and four detectors can establish sixteen channels or paths between the emitters and the detectors, or up to sixteen different paths between the emitters and the detectors. Further, as the number of emitters and detectors increases, the pulse oximeter measurement may be less sensitive to errors and / or spurious readings. Although an equal number of emitters and detectors are described herein, any number of emitters and detectors can be used, including an unequal number of emitters and detectors.

[0076] Figure 2 Each window of can include a green light emitter, an infrared light emitter, and a red light emitter. For example, the emitter can include a green light emitter 205a, an infrared light emitter 205b, and a red light emitter 205c. Figure 2 Other green, infrared, and red light emitters of can be numbered similarly. In some examples, the green light emitter can be used to measure or monitor the user's heart rate. Additionally, the green light emitter can be located on the outer diameter and farthest from the central part (or center) of the wearable device. The green light emitter can be positioned on the outer diameter because the green light can be detected by one or both of the two closest or adjacent detectors. Due to this local sensing of the green light in this example, for example, when detectors 225a and 250a are the two detectors that can sense the green light emitted from the green light emitter 205a, the distance between the green light emitter 205a and the detectors 235a and 240a may not be relevant. In some examples, it may be possible for detectors 235a and 240a to detect the green light emitted by the green light emitter 205a.

[0077] The infrared light emitter and the red light emitter can be detected by any one or all of the detectors 225a, 235a, 240a, and 250a, regardless of how close or far the detectors are from the emitter. In some examples, the red light emitter can be positioned closer to the central part (or center) of the wearable device than the infrared light emitter. The red light emitter can be positioned closer to the middle of the wearable device because generally red light is absorbed more than infrared light, and thus red light is more sensitive to clipping than infrared light.

[0078] In Figure 2 , the emission areas of the emitters 205a to 205c of the emitter windows 205, 210, 215, and 225 are each depicted as square, but can be any suitable shape that allows the emitter to emit an appropriate amount of light. Similarly, the detection areas of the detectors 225a, 235a, 240a, and / or 250a are shown as square, but can be another shape or configuration that allows the detector to detect an appropriate amount of light. Further, the individual emitters (e.g., light-emitting diodes (LEDs)) depicted as square in Figure 2 can be positioned within a circular aperture, and the individual detectors shown as square can also be positioned within a circular aperture. The emitters and detectors are also depicted as being generally equidistant from each other, but can be positioned at various distances from each other, or can be positioned at the distances as needed. Additionally, if the distance between the emitter and the detector changes, the detection angle between the emitter and the detector can also be different from the layout 200 depicted in Figure 2 . The distance between the emitter and the detector can be selected to optimize battery life and power savings. In some examples, depending on the absorption and reflection properties of the wavelength of the light, some emitters and detectors can be positioned closer together. The shapes and layout configurations of the emitters and detectors are discussed in further detail herein.

[0079] In Figure 2 some examples, the wearable device can include windows 205, 210, 215, and 220 or apertures through which light emitted from the emitter can pass. Similarly, the windows 225, 235, 240, and 250 can also be used as apertures through which light reflected and / or backscattered from the wrist tissue can return to the wearable device and be detected by the detector. The windows 205, 210, 215, and 220 can be disposed in the back cover of the wearable device. The back cover or the skin-side cover member can be a part of the outer surface of the wearable device facing the skin side, as discussed in relation to Figure 1A and Figure 1B . In some examples, the window can provide optical isolation for the detector such that the detector does not directly receive light from the emitter. The optical isolation via the window and the back cover is discussed in further detail herein.

[0080] Although the windows 205, 210, 215, 220, 225, 235, 240, and 250 are circular in Figure 2 for purposes of illustration, and such windows may be of any suitable shape, as discussed further herein. Additionally, for purposes of illustration, the windows are of Figure 2 substantially the same size in

[0081] Figure 3 FIG. 300 shows an example layout of the emitter and detector. In some examples, the layout 300 of the emitter and detector may be incorporated into some aspects of the wearable device 100, as described with reference to Figures 1A to 2 In the example of Figure 3 the layout 300 of the emitter and detector may be included in the wearable device to provide physiological and / or biometric measurements of the user of the wearable device 100 for Figure 1A and Figure 1B wear.

[0082] By way of example and for purposes of description, the layout 300 of the emitter and detector may be positioned on the back side or the skin-facing side of the wearable device 100, as discussed with reference to Figure 1A and Figure 1B The layout 300 of the emitter and detector may be protected by a back cover or a skin-side cover member (not shown in Figure 3 ) having a window or aperture, which is discussed further herein.

[0083] As Figure 3 shown, the window 345 may include emitters 305a, 305b, and 305c. Similar to Figure 2 each emitter window may include a green light emitter, an infrared light emitter, and a red light emitter. For example, the emitter 305 may include a green light emitter 305a, an infrared light emitter 305b, and a red light emitter 305c. Additionally, in Figure 3 the window 350 may include detectors 325, 330, 335, and 340. The window 363 may be a window in the central portion of the back cover. The window, emitter, and detector may each incorporate features of similar components described in other embodiments.

[0084] The system between the transmitter window 345 and the detector window 350 respectively includes a plurality of paths including a short path 355 and a long path 360 (i.e., for each transmitter (or each detector), there are at least a first and a second optical path (or light detection path) having corresponding first and second lengths). Further, the method of mounting or inserting the detector window 350 into the back cover can provide optical isolation such that stray light from the transmitter is not detected by the detector. In some examples, the window may not be able to provide sufficient light blocking for internal crosstalk of the reflective sensing device alone.

[0085] Each of the transmitters 305, 310, 315, and 320 includes a short path 355 and a long path 360 to each of the other detectors 325, 330, 335, and 340. For example, transmitter 320 has a short path 355 to detector 325, a short path to detector 340, a long path to detector 330, and a long path to detector 335. The long path and the short path can provide mapping of arterial or venous blood flow for pulse oximetry. Further, the long path and the short path can provide an array of arterial or venous blood flow signals from potentially different perspectives for pulse oximetry. Each detector may be capable of receiving or detecting light from each of the transmitters 305, 310, 315, and 320 and each wavelength of the transmitters. For example, detectors 325, 330, 335, and 340 may each be capable of sensing green light, infrared light, and red light.

[0086] Figure 3 Depicting four transmitters and four detectors, which can provide sixteen different optical paths between the transmitter and the detector. Although Figure 3 and other examples discussed herein may use four transmitters and four detectors, any number of transmitters and detectors can be used as needed. For example, as shown in other embodiments herein, three transmitters and three detectors can be used in the reflective sensing device, and nine optical paths or at most nine optical paths can be provided between the transmitter and the detector. In some examples, the higher the number of paths, the less sensitive the measurement may be to incorrect data. With more measurements, it may be easier to use redundant or consistent measurements to verify the data, and incorrect data can also be more easily identified by comparing outlying measurements or inconsistent data.

[0087] Additionally, the greater the distance between the emitter and the detector, the greater the amount of wrist tissue that can be imaged and / or optically probed using the measurements. One or more of the path signals can be used to image and / or optically probe the wrist tissue, and thus the number of emitters and detectors and the distance between the emitter and the detector can be appropriately selected to image and / or probe as much wrist tissue as possible for the corresponding size of the wearable device. In some examples, the higher the number of emitters and detectors, the greater the number of optical paths above which wrist tissue is probed and / or measurements are made to image the wrist tissue. However, when optimizing the appearance of the wearable device and considering the battery life of the wearable device, the number of emitters and detectors may also be considered.

[0088] Although the reflective sensing device may have multiple emitters and detectors, there may be a predetermined order for turning the emitters and detectors on and off. In some examples, emitter 305 may be turned on, but emitter 305 may turn on a single green light emitter 305a. Continuing with this example, adjacent detectors (detector 325 and detector 330) may be turned on to detect the amount of green emitted light that returns. In other examples, emitter 305 may be turned on and infrared light emitter 305b and red light emitter 305c may be turned on to emit light, and all of detectors 325, 330, 335, and 340 may be turned on to detect the amount of infrared light and red light that returns. Some implementations may turn on emitter 305 and 315, or may turn on emitter 315 and 320, or may turn on all of the emitters at once. The order in which the emitters may be sequentially turned on may be predetermined or may be random. In some examples, all of the emitters and detectors may be turned on simultaneously.

[0089] As discussed previously, detectors 325, 330, 335, and 340 can sense the amount of return light (e.g., reflected light and / or backscattered light) that has passed through the user's arterial blood. The detectors can include additional associated circuitry that can be configured to process the detected light measurements into signals and can provide these electrical signals to a processor. In some examples, the detected light measurements can individually be from each detector or can be aggregate measurements derived from two or more detectors. The processor can be configured to receive signals (or indicators, or outputs) from one or more of the detectors. In some examples, the processor can be configured to receive signals from one or more of the transmitters. Additionally, the processor can further be configured to use at least a subset of the received signals (or indicators or outputs) and in some cases the received light or detected light, to determine the degree of oxygenation. In some examples, the processor can be configured to receive signals (or indicators or outputs) representing detected red and infrared range wavelengths from at least a first detector and a second detector (e.g., detectors 325 and 330). The processor can then use a subset of the signals (or indicators or outputs) representing the received red range wavelength and the received infrared range wavelength to determine the degree of oxygenation.

[0090] In some examples, the processor can be configured to select which detector measurements to use and can select a subset of the received detector measurements. Additionally or alternatively, the program can be configured to select signals and / or measurements associated with one or more of the transmitters for use. The processor can be configured to select a subset of measurements using various factors, such as determining outlying measurements that are in error or measurements of false readings that can detect what may seem like useful measurements but may not conform to the assumptions made for the measurement. The processor can utilize data received from multiple optical paths or channels and weight various characteristics to identify useful data, for example, by analyzing multiple views and / or regions of the wrist tissue obtained by taking measurements through multiple optical paths. In other examples, the processor can use all of the data received from the detectors. Further, in some cases, the measurements and / or signals received from the detectors can be weak signals. By selecting which detector measurements to use, the processor can select signals that are strong enough or, in some examples, can select multiple signals (e.g., the amount of detected light) to add together. Additionally, the transmitter and the detector can be positioned far from each other because the detector signals can be added together.

[0091] In Figure 3 the example, the amount of green light emitted by transmitter 305a can be detected by the closest detectors (detectors 325 and detector 330). As previously discussed and as Figure 3As shown, the green light emitters 305a, 310a, 315a, and 320a can be positioned furthest from the central portion of the wearable device back cover. The green light emitters may be less sensitive to position because green light can be detected by the closest detector. Additionally, by positioning the green light emitters close to the detector, the battery life and power savings of the wearable device can benefit. Generally, when green light is incorporated into a wearable device, the green light can be used for heart rate detection and monitoring. In some embodiments, the detected green light can also be used to distinguish good detector readings from false detector readings (i.e., the amount of detected green light can be used to determine a subset of the red and infrared light measurements (or indicators) for determining the degree of oxygenation).

[0092] Figure 4 An example layout 400 of emitters and detectors is shown. In some examples, the layout 400 of emitters and detectors can be incorporated into some aspects of the wearable device 100, as referenced Figures 1A to 3 as described. In Figure 4 the example of, the layout 400 of emitters and detectors can be included in the wearable device to provide physiological and / or biometric measurements of a user wearing the wearable device as discussed in relation to Figures 1A to 3 discussed.

[0093] By way of example and for illustrative purposes, the layout 400 of emitters and detectors can be positioned on the back side or skin-facing side of the wearable device 100, as referenced Figure 1A and Figure 1B discussed. The layout 400 of emitters and detectors can be protected by a back cover or skin-side cover piece having a window or aperture, which is discussed in further detail herein.

[0094] As Figure 4As shown, the layout 400 may include a window 445 for the emitter 405 and windows 450 for the near detector 430 and the far detector 435. The optional window 463 may be a window above the central portion of the back cover 407 of the wearable device. The window may be disposed in an opening 475 in the back cover 407 and may sit on or contiguous to such a protrusion 470. Alternatively, some or all of the windows may be integrated with the back cover 407 and defined by other portions of the back cover 407 where there is no optical shielding (e.g., ink (optically opaque ink), film, coating, or surface treatment) thereon. For example, the optical shielding may be on a first portion (e.g., non-window portion) of the back cover 407 and not present on a second portion of the back cover 407. In some cases, by way of example, the window 445 for the emitter 405 may be defined by the absence of an optical shielding (e.g., ink, film, coating, or surface treatment) surrounding the window 445, and the windows 450 for the near detector 430 and the far detector 435 may sit on or contiguous to such a protrusion 470. The openings and protrusions in the back cover are discussed in further detail herein. The back cover 407 and / or the windows 445, 450, 463 may be formed of sapphire, glass, plastic, or other materials.

[0095] In some cases, the emitter 405, the near detector 430, and the far detector 435 may be mounted to a printed circuit board (PCB), and the PCB may be attached to the back cover 407 by one or more components that form a set of optical barriers (or walls) between the PCB and the back cover 407. In these cases, the combination of the back cover 507, the PCB, and the one or more components that form the set of optical barriers (or walls) may define different chambers that separately house the emitter 405, the near detector 430, and the far detector 435 therein.

[0096] Figure 4 The window of may form a surface with the back cover, and the back cover 407 may be adjacent to the wrist tissue 465. The emitter 405 may include an infrared light emitter 405b and a red light emitter 405c. The light from the infrared light emitter 405b and the red light emitter 405c may be transmitted into the tissue 465. The light reflected from the arterial blood flow and / or that has passed through the user's arterial blood and / or tissue 465 may pass through the window 450 to the near detector 430 and the far detector 435. As previously discussed, the near detector 430 and the far detector 435 may be configured to receive or detect light from any of the emitters and receive or detect reflected green light, infrared light, and / or red light. The protrusion 470 may at least partially serve as an optical isolator between the (multiple) emitter windows and the detector windows, which will be discussed in further detail herein.

[0097] As in Figure 4As depicted, emitter 405c can emit red light through window 445. The red light can pass through window 445 to tissue 465. The red light can reflect off a first region of the tissue and return through window 450 to be received or detected by near detector 430. Additionally, the red light can reflect off a second region of the tissue and return through window 450 to be received or detected by far detector 435. Further shown in Figure 4 is that the depth to which the red light reflected off the first region of the tissue penetrates the tissue may not be as deep as the depth to which the red light reflected off the second region of the tissue penetrates the tissue. By placing the emitter and the detector far from each other, the light can penetrate different depths in the tissue, thus enabling more thorough imaging and / or detection of wrist tissue. The red light from emitter 405b can also enter window 445 at an angle such that it may not pass through the window due to total internal reflection (TIR). As Figure 4 shown, the red light can reflect off the outer surface of the window towards the skin and reflect back into the window. Since the reflected red light can be absorbed by barrier or protrusion 470 that separates window 445 from window 450, the reflected red light may not be detected by detector 430. Barrier or protrusion 470 can isolate the light directly emitted from the emitter from being detected by the detector, thus preventing unwanted internal crosstalk.

[0098] The light emitted from infrared light emitter 405b can pass through window 445 and enter skin 465. The infrared light can reflect off arterial blood vessels in skin 465 and can pass through window 450. The infrared light can then be sensed by far detector 435. In Figure 4 the example, the infrared light may not be received by near detector 430. As shown, due to the angle of infrared light emission, some of the emitted infrared light may not pass through window 445 and instead may reflect off the window due to TIR. This infrared light can reflect off the window and return to the window. Since the emitted infrared light that reflects off the window rather than off the tissue may be blocked by optical barrier or protrusion 470, it may not be detected by detector 430. Optical barrier or protrusion 470 can isolate the light emitted at certain angles within window 445 and at least partially reduce or prevent internal crosstalk, and can prevent the light emitted by the emitter and not first passing through the user's tissue from being directly sensed by the sensor. In Figure 4 some examples, the infrared light can reflect, scatter, and / or backscatter off the tissue and into near detector 430. Although not depicted in Figure 4In this case, the red light emitted by the red light emitter 405c can be reflected, scattered, and / or backscattered away from the tissue and into one of the detectors 430 and 435. Similarly, the infrared light emitted by the infrared light emitter 405b can be reflected, scattered, and / or backscattered away from the tissue and into one of the detectors 430 and 435. Methods for forming these windows with an optical barrier via the protrusions 470 and other methods for providing optical isolation within the windows are discussed in further detail herein.

[0099] Figures 5A to 5D Each of which is shown as in reference Figures 1A to 4 Different views of the back cover and / or the back side of the previously described wearable device. Figure 5A An example 500 of the back side 510 of the wearable device is shown. In some examples, the back side 510 can be incorporated into some aspects of the wearable device 100, as described in reference Figures 1A to 4 As described. In the example of FIG. 5, the back side 510 can be incorporated into the wearable device to provide physiological measurements and / or biometric measurements of a user wearing the wearable device, as discussed in relation to Figures 1A to 4 As Figure 5A As shown, the back side 510 of the wearable device can include a back cover 507. The back cover 507 can have six insertion windows disposed around a central portion (or central window 563) of the back cover 507. The window 545 can provide an aperture through which the emitter can emit light, and the window 550 can provide an aperture through which the detector can detect light reflected from the arterial blood flow of the user and / or can detect backscattered light that has passed through the arterial blood of the user. The windows can be inserted into openings extending through the back cover 507. Although the back cover 507 can include insertion windows, such windows can form a smooth surface with the back cover 507.

[0100] Figure 5B An example elevation view of the back cover 507 of the wearable device is shown. In some examples, the back cover 507 can be incorporated into some aspects of the wearable device 100, as described in reference Figures 1A to 5A In Figure 5B The example of, the back cover 507 can be incorporated into the wearable device to provide physiological measurements and / or biometric measurements of a user wearing the wearable device, as discussed in relation to Figures 1A to 5A As discussed.

[0101] As Figure 5B As shown, the side view can be oriented towards as Figure 5AA cross-section of the middle of the dorsal side of the wearable device depicted. The back cover 507 may include six peripheral windows disposed around a central portion of the back cover 507. In some embodiments, the central portion may include an optional central window. As previously mentioned, any suitable number of windows may be used, and the six windows are for illustrative and discussion purposes only. Window 545 may provide an aperture through which a transmitter may emit light, and window 550 may provide an aperture through which a detector may detect light reflected from and / or backscattered from the user's tissue. Window 563 (as shown in Figure 5A , Figure 5B , and Figure 5C ) may be in the central portion (or center) of the wearable device and is optional. In some examples, window 563 may be used to enable an optical sensor to detect whether the wearable device is in contact with the user's skin, or to monitor the user's heart rate, or for other purposes. For example, an IR LED or other transmitter may emit IR light through the central window in some cases, and an IR detector may detect a portion of the emitted IR light that returns through the central window after being reflected or scattered from the user. The returned portion of the emitted IR light may be used to determine whether the back cover is adjacent or not adjacent to the user's wrist (or is no longer adjacent to the user's wrist), or the returned portion of the emitted IR light may be analyzed to determine the user's heart rate. In some cases, the central window and / or optical sensing through the central window may be incorporated into any of the device embodiments described herein.

[0102] In Figure 5B , the back cover 507 may have an inner surface 504 that may be inside the wearable device and an outer surface 506 that may be outside the wearable device. Further, the back cover 507 may include a substrate that may define at least a portion of the inner surface 504 and the outer surface 506 of the wearable device. The outer surface 506 may be the surface that may contact the skin of the user wearing the wearable device. The back cover 507 or the skin-side cover member may have an opening that may extend through the back cover, for example, such an opening may extend through the inner surface and the outer surface of the back cover 507. The back cover 507 may also include a set of protrusions 570 adjacent to the opening, as shown in Figure 5B . In some examples, the protrusions 570 may be stepped protrusions that may extend completely around the opening, as related to Figures 5A to 5DAs shown and discussed, or such protrusions may be positioned at selected angles, or other suitable shapes or gradients around the opening, as discussed herein. The window may be disposed in the opening and may abut the protrusion 570. The window may be joined to the back cover 507 in place and also joined to the protrusion, which may hold the window in position such that the window does not move or become tilted in the opening of the back cover 507. The window may be joined using any suitable method (such as adhesives, melting, etc.). In some examples, the entire back cover 507 may be optically opaque or the entire back cover 507 may be optically transparent. The back cover 507 may be optically opaque or optically transparent to light emitted and / or detected or received by the wearable device.

[0103] In Figure 5B some examples, the protrusion 570 may extend into the opening of the back cover 507. The protrusion may extend into the opening to provide an edge upon which the window may rest. The protrusion may provide a protruding edge upon which the window may sit. The protrusion may ensure that the window does not fall through the back cover and into the internal portion of the wearable device. These protrusions may be positioned adjacent to or near the inner surface of the back cover. Alternatively, the protrusions may be adjacent to or near the outer surface of the back cover such that the window may be inserted from the outside or outer surface of the back cover.

[0104] In some examples, the back cover 507 with the protrusions may be an optically opaque material and the window may be optically transparent. As used herein, optically opaque may not block all light across all wavelengths 100%, and instead may block light of a target wavelength that may be appropriately attenuated. In this example, the protrusions may provide at least some optical isolation for the detector such that stray light from the emitter is not received at the detector. Over a certain angular range, light leaving the emitter may be reflected off the window and back towards the detector rather than passing through the window and into the tissue. Without optical isolation, this light reflected off the window may be received by the detector and may provide false measurement values. With optical isolation, light reflected off the window and back towards the detector may be prevented from reaching the detector by the optically opaque protrusions that optically isolate the detector. In some examples, the window above the detector may have an optical barrier, while in other examples, the window above the emitter may have an optical barrier, and in further examples, the window above both the emitter and the detector may have an optical barrier. In some examples, the optical barrier may be formed by coating such sides of the opening and / or such sides of the window (e.g., around the opening or window) with an optically opaque ink or other material that is optically opaque to the emitted and detected light. Additionally or alternatively, the optical barrier may be formed by one or more of an ink, film, coating, or surface treatment disposed between the window and its corresponding opening (or protrusion). The ink, film, coating, or surface treatment may be formed on or applied to the window or opening (or protrusion) before joining and attaching the window to the opening (or protrusion).

[0105] In some examples, the detector can detect a specific range of wavelengths, such as IR wavelengths. In this example, an optical barrier or optically opaque material can block the specific range of wavelengths detected by the detector (such that the emitted wavelength is not detected by the detector without first passing through the back cover 507); or the optical barrier can block all wavelengths of light; or the optical barrier can block at least the wavelengths in the IR range and a certain range on either side of the IR wavelength.

[0106] In some embodiments, the back cover 507 and / or the windows 545, 550, 563 can be formed of sapphire, glass, plastic, or other materials. Although the windows can be optically transparent, in some examples, the distance between the protrusions can at least partially determine the size of the aperture through which light can pass. As previously discussed, the windows can be adjacent to the protrusions, and the protrusions can be an optical barrier between the emitter and the detector. The protrusions can have a protruding edge for the windows to sit on, so the distance between the inner sides of the protrusions can be less than the opening and / or the windows. Thus, the area through which light can pass can be less than the opening in the back cover, and instead can be the internal distance between the protrusions.

[0107] Figure 5C An example of the back cover 507 of a wearable device is shown. In some examples, the back cover 507 can be incorporated into some aspects of the wearable device 100, as described with reference to Figures 1A to 5B as described. In Figure 5C the example of, the back cover 507 can be incorporated into the wearable device to provide physiological and / or biometric measurements of a user wearing the wearable device, as discussed in relation to Figures 1A to 5B as discussed.

[0108] As Figure 5C shown, the perspective view can be an example of the back cover 507 of the wearable device as depicted in Figure 5A and Figure 5B The back cover 507 can include six windows 545, 550 disposed around a central portion (or optional central window 563) of the back cover 507. As previously mentioned, any suitable number of windows (such as eight windows) can be used, and six windows are used in the figures of this specification for illustrative and discussion purposes only. The window 545 can provide an aperture through which the emitter can emit light, and the window 550 can provide an aperture through which the detector can detect light reflected from and / or backscattered by the user's tissue. The window 563 can be in the central portion (or center) of the wearable device. The back cover 507 and / or the windows 545, 550, 563 can be formed of sapphire, glass, plastic, or other materials.

[0109] The back cover 507 may include an opening 546 that extends through the back cover. The opening 546 may include a protrusion that may be stepped, tapered, cup-shaped, or any other suitable profile to at least partially support a window in the back cover 507. In some examples, the protrusion may be tapered, and the cone may be a shallow cone as shown in Figure 5D . In still other examples, the cone may extend through the opening of the back cover 507. In this example, the window may be the depth of the back cover 507.

[0110] In some examples, the protrusion 570 may define the size of the aperture through which light may pass or through which it may be detected. The windows 545, 550 may rest on or be at least partially supported by the protrusion 570, and the windows 545, 550 may be optically transparent such that light may pass through the windows 545, 550 or may be detected through such windows. In some examples, the back cover 507 may be optically opaque.

[0111] In other examples, the back cover 507 may be optically translucent or transparent, and the windows 545, 550 may be optically translucent or transparent. In this example, the optically transparent back cover 507 may include the protrusion 570, but the protrusion 570 may be coated with an optically opaque material (such as ink) to provide light blocking or optical isolation between the emitter and the detector. Additionally, the protrusion 570 may be optically transparent, and the edges of the windows 545, 550 may be coated with optically opaque ink. In yet another embodiment, both the protrusion 570 and the edges of the windows 545, 550 may be coated with optically opaque ink to provide an optical barrier between the emitter and the detector.

[0112] Figure 5D An example side view of the back cover 507 of a wearable device is shown. In some examples, the back cover 507 may be incorporated into some aspects of the wearable device 100, as described with reference to Figures 1A to 5B . In the example of Figure 5D , the back cover 507 may be incorporated into the wearable device to provide physiological and / or biometric measurements of a user wearing the wearable device, as discussed with respect to Figures 1A to 5C .

[0113] As Figure 5D shown, the view may be an example of the back cover 507 of the wearable device depicted as in Figure 5C . Similar to Figure 5B , Figure 5D shows the protrusion 570 on which the windows 545, 550 may rest. Relative to the stepped protrusion of Figure 5B , the protrusion 570 of Figure 5D may be tapered.

[0114] Figures 6A to 6C Each of which is shown in as Figures 1A to 5DDifferent views of the back cover on the dorsal side of the previously described wearable device. Figure 6A An example 600 of the dorsal side 610 of a wearable device is shown. In some examples, the dorsal side 610 may be incorporated into some aspects of the wearable device 100, as referenced Figures 1A to 5D and described. In Figure 6A the example, the dorsal side 610 may be incorporated into the wearable device to provide physiological and / or biometric measurements of a user wearing the wearable device, as related to Figures 1A to 5D and discussed.

[0115] As Figure 6A shown, the dorsal side 610 of the wearable device may include a back cover 607. The back cover 607 may have four to eight insertion windows that may provide sixteen optical sensing paths or channels. The window 650 may provide an aperture through which a detector may detect light reflected off of a user's arterial blood flow and / or may detect backscattered light that has passed through the user's arterial blood. The back cover and / or the window may be formed of sapphire, glass, plastic, or other materials. The window 650 (and in some cases, the window 645) shown in Figure 6A may be inserted into an opening extending through the back cover 607. Although the back cover 607 may include insertion windows, such windows may form a smooth outer surface with the back cover 607. As Figure 6A depicted, four of the eight windows (e.g., the window 650) may have an optically opaque material or an opaque material 687 around the perimeter of the window, which may determine the size of the aperture through which light may pass. The optically opaque material or the black material around the perimeter of the window may be an optical barrier for all light or at least for the wavelength range emitted and / or received by the transmitter and detector of the wearable device. The other four windows (e.g., the window 645) may be an integral part of the monolithic back cover structure (i.e., the window 645 may not be an insertion window) and may be defined by an optical shield (e.g., ink, film, coating, or surface treatment) on the back cover 607. For example, the ink film, coating, or surface treatment may be on a first portion of the back cover 607 and not on a second portion of the back cover 607.

[0116] Figure 6B An example of the back cover 607 of the wearable device is shown in a side view. In some examples, the back cover 607 may be incorporated into some aspects of the wearable device 100, as referenced Figures 1A to 6A and described. In Figure 6B the example, the back cover 607 may be incorporated into the wearable device to provide physiological and / or biometric measurements of a user wearing the wearable device, as related to Figures 1A to 6A and discussed.

[0117] As Figure 6B shown, the side view may be as Figure 6ACross-section of the dorsal side of the wearable device depicted. As Figure 6A depicted, the back cover 607 may include eight windows. As previously mentioned, any suitable number of windows may be used, and the eight windows are for illustrative and discussion purposes only. Each of the windows 645 may provide an aperture through which the emitter may emit light, and each of the windows 650 may provide an aperture through which the detector may detect light reflected from and / or backscattered from the user's tissue. By way of example, the cross-section shown in Figure 6B shows the window 650 inserted and extending through the back cover 607. As previously discussed, the window 645 may be an integral part of the back cover 607 and not inserted. As Figure 6A and Figure 6B shown, there may be no window in the central portion (or center) of the wearable device. However, in some embodiments, there may be a central window as shown in Figure 5A .

[0118] In Figure 6B , the back cover 607 may have an inner surface 604 that is inside the wearable device and an outer surface 606 that is outside the wearable device. The back cover 607 may include a substrate that at least partially defines the inner surface 604 and the outer surface 606 of the wearable device. The outer surface 606 may be the surface that contacts the skin of the user wearing the wearable device. Similar to Figure 5B , in Figure 6B , the back cover 607 or the skin-side cover member may have an opening that extends through the back cover. For example, the opening may extend through the inner surface 604 and the outer surface 606 of the back cover 607. In this non-boss example of Figure 6B , the optically transparent frit 687 of glass or sapphire may include a central portion that is hollow (e.g., similar to a hollow tube) and is generally cylindrical. The frit 687 may be inserted into the opening of the back cover 607, and the frit may abut the perimeter of the opening and be melted or bonded to the back cover 607 as shown in Figure 6B . The window 650 may be disposed in the center of the frit 687, and the window may be joined and bonded in place to the back cover 607. In some examples, the window 650 may provide an aperture for detecting reflected light and / or backscattered light passing through the user's arterial blood flow. By melting or bonding the frit and the window 650 to the back cover, this may fix the frit and the window in position so that the window does not move or become tilted in the opening of the back cover 607. Additionally, the inner surface 604 and the outer surface 606 of the back cover 607 may be ground or polished to provide a back cover with a smooth surface. Further, although the frit and the window may be depicted as circular, the frit and the window may be of any suitable shape. In some examples, as long as the frit acts as an optical barrier and blocks the light path from the emitter to the detector, the inner diameter of the frit may be of any shape.

[0119] In Figure 6BIn some examples, the frit may be optically opaque. The frit material itself may be optically opaque, or the frit may be coated with an optically opaque material (such as an optically opaque ink or a neutral color ink that may not distinguish between infrared light and red light). The frit may be inserted into the opening, and the frit may have a frit opening similar to a ring. Because the frit is similar to a ring with a hollow central opening, the inner diameter of the frit may provide an aperture through which light can still be detected. In some embodiments, the frit may be a glass frit (e.g., a black glass frit) that can be centered in the opening of the back cover 607. The black glass frit may form an optical bond with the sapphire opening after melting or bonding, and then the two sides of the back cover may be polished to achieve a smooth surface. In this embodiment, the shielding of the emitter and / or detector may be defined by the shape of the ink or frit. As long as the frit blocks the optical path from the emitter to the detector, the frit can be of any shape.

[0120] In some examples, the back cover 607 may be an optically transparent material, and the window may also be optically transparent. The optically opaque frit can provide at least some optical isolation for the detector so that stray emitter light is not received at the detector. Within a certain angular range, the light leaving the emitter may be reflected by the window and return towards the detector rather than passing through the window and into the tissue. Without optical isolation, this light reflected by the window can be received by the detector and may provide an incorrect measurement value. With optical isolation, the light reflected by the window and returning towards the detector can be blocked from reaching the detector by the optically opaque frit that optically isolates the detector.

[0121] Similar to Figures 5A to 5C , the size of the aperture through which light can pass to reach the detector can be determined at least in part by the inner diameter of the frit and / or the ink on the periphery of the frit. In Figure 6B , the inner diameter of the frit and / or the ink on the inner diameter of the frit can be an optical barrier between the emitter and the detector. Thus, the area through which light can pass can be smaller than the opening in the back cover and can instead be the inner diameter of the frit.

[0122] Figure 6C An example of the back cover 607 of the wearable device is shown. In some examples, the back cover 607 can be incorporated into some aspects of the wearable device 100, as described with reference to Figures 1A to 6B . In Figure 6C example, the back cover 607 can be incorporated into the wearable device to provide physiological and / or biometric measurements of the user wearing the wearable device, as discussed in relation to Figures 1A to 6B .

[0123] As Figure 6C shown, the isometric view can be as Figure 6A and Figure 6BAn example of a back cover 607 of a wearable device is depicted. The back cover 607 may include four to eight windows. The window 645 may provide an aperture through which a transmitter may emit light, and in some cases, may be integrated with the back cover 607 and defined by other portions of the back cover 607 where there is no optical shielding (e.g., ink (optically opaque ink), film, coating, or surface treatment). For example, the optical shielding may be on a first portion of the back cover 607 and not present on a second portion of the back cover 607. The window 650 may provide an aperture through which a detector may detect light reflected from and / or backscattered from a user's tissue, and may be inserted into the back cover 607. In Figure 6C there may not be a separately provided window in the central portion (or center) of the wearable device. However, the back cover 607 or a portion thereof may be optically transparent to the wavelength range of electromagnetic radiation transmitted and / or received through the central portion of the back cover in some cases.

[0124] In Figure 6C the back cover 607 may include an opening extending through the window 650 of the back cover. The opening may be an annular frit having an opening in the central portion, and the frit may be inserted into the opening and act as a sleeve fitting within the opening of the back cover. The inner diameter opening of the frit or the ink coated on the frit may determine the size of the aperture through which light may pass or be detected. Although the term frit may be used herein, a frit may be understood as a hollow sleeve, ring, and / or tubular component or hollow cylindrical component, regardless of the material composition.

[0125] The window 650 may be disposed in the central opening of the frit and may be optically transparent such that light may pass through or be detected through the window. The frit 687 may act as an optical barrier between the transmitter and the detector and may minimize or prevent internal crosstalk. Using optical isolation, any transmitter light reflected from the window and back towards the detector may be blocked by the optically opaque frit of the detector from reaching the detector.

[0126] Figure 7 An example 700 of a back cover, a transmitter, a detector, and a waveguide of a wearable device is shown in a side view. In some examples, the back cover 707 may be incorporated into the wearable device to provide physiological and / or biometric measurements of a user wearing the wearable device, as related to Figures 1A to 6C discussed.

[0127] As Figure 7 shown, the side view may be a cross-section of the wearable device as depicted in Figure 5A The back cover 707 may include six windows, but Figure 7 the side view of Figure 7In this case, the emitter and the detector can be protected by a back cover or a skin-side cover member having a window or an aperture. Window 745 provides an aperture through which the emitter can emit light, and window 750 can provide an aperture through which the detector can detect light reflected from and / or backscattered from the user's tissue. As Figure 7 shown, window 745 is for emitter 705, and window 750 is for near detector 730 and far detector 735. Optional window 763 can be a window above the central portion of back cover 707 of the wearable device. The window can be disposed in opening 776 in back cover 707, and back cover 707 can be an optically transparent or optically opaque back cover. The opening in the back cover can extend through the inner surface and the outer surface of the back cover. Alternatively, some or all of the windows can be integrated with back cover 707 and defined by other portions of back cover 707 where there is no optical shielding (e.g., ink (optically opaque ink), film, coating, or surface treatment). For example, the optical shielding can be on the first portion (non-window portion) of back cover 707 and absent on the second portion of back cover 707. In some cases, by way of example, window 745 for emitter 705 can be defined by the absence of optical shielding (e.g., ink, film, coating, or surface treatment) surrounding window 745, and window 750 for near detector 730 and far detector 735 can be disposed in opening 776 in back cover 707. Back cover 707 and / or windows 745, 750, 763 can be formed of sapphire, glass, plastic, or other materials.

[0128] In some cases, emitter 705, near detector 730, and far detector 735 can be mounted to a PCB, and the PCB can be attached to back cover 707 by one or more components that form a set of optical barriers (or walls) between the PCB and back cover 707. In these cases, back cover 707 in combination with the PCB and one or more components that form the set of optical barriers (or walls) can define different chambers for separately housing emitter 705, near detector 730, and far detector 735 therein.

[0129] In Figure 7 this case, the optical path for the emitted light between emitter 705 and window 745 can be determined by emitter waveguide 775. Emitter waveguide 775 can guide the emitted light from the emitter to the window. In some examples, light can be received at the first end of the waveguide such that the light reflects off the inside of the waveguide walls. The light can exit from the second end of the waveguide and pass through the window and / or into the tissue of the user wearing the device. Emitter waveguide 775 can internally reflect at the wavelength of the generated or emitted light or around that wavelength. Further, emitter waveguide 775 can guide the emitted light via total internal reflection in waveguide 775 and guide it to emitter window 745. Additionally, emitter waveguide 775 can be configured to transmit light from the emitter to the wrist of the user wearing the wearable device.

[0130] As Figure 7 depicted, emitters that can emit different optical wavelengths may each have an emitter waveguide 775, but in some embodiments, one waveguide may be configured to receive the emitted light from more than one emitter. For example, the emitter waveguide 775 may be configured to receive all of the emitted green light, emitted red light, and emitted infrared light, and direct the light to the emitter window 745. In other examples, the emitter waveguide 775 may extend through the back cover of the wearable device, and the back cover may not include a window. In this example, the emitter may emit light through the housing of the reflective sensing device.

[0131] Also shown Figure 7 is that the optical path for the reflected-off light and / or backscattered light that has passed through the arterial or venous blood flow in the wrist between the near detector 730 and the detector window 750 may be determined by the near waveguide 780. The near waveguide 780 may direct the reflected light from the window to the near detector 730. The near waveguide 780 may internally reflect at the wavelength of the light received by the near detector 730 or around that wavelength. In some examples, the near detector 730 may internally reflect in the red light, infrared light, and / or green light wavelength range or around that wavelength range. Further, the near waveguide 780 may direct the reflected light from the window via total internal reflection in the waveguide 780 and direct it to the near detector 730. In some examples, the near waveguide 780 may extend through the back cover of the wearable device, and the back cover may not include a window.

[0132] Similarly, the optical path between the far detector 735 and the detector window 750 may be determined by the far waveguide 785. The far waveguide 785 may direct the reflected light from the detector window 750 to the far detector 735. The far waveguide 785 may internally reflect at the wavelength of the light received by the far detector 735 or around that wavelength. In some examples, the far detector 735 may internally reflect in the red light, infrared light, and / or green light wavelength range or around that wavelength range. Further, the far waveguide 785 may direct the reflected light from the window via total internal reflection in the far waveguide 785 and direct it to the far detector 735.

[0133] In some examples, the near detector 730 and the far detector 735 may include additional associated circuitry that may be configured to process the detected light measurements into signals and provide these electrical signals to a processor. The processor may be configured to receive signals from one or more of the detectors. Additionally, the processor may further be configured to determine the degree of oxygenation using at least a subset of the received signals and in some instances the received detected light. In some examples, the processor may be configured to receive signals representing detected red and infrared range wavelengths from the far detector 735 and the near detector 730. The processor may then use a subset of the signals representative of the received red range wavelength and the received infrared range wavelength to determine the degree of oxygenation.

[0134] Figure 7 The waveguide of Figure 7 may be formed of sapphire, plastic, glass, or any other suitable material. In some examples, the waveguide may be an optical fiber waveguide, such optical fiber waveguides may be similar to plastic rods having internal reflective materials that reflect light in the green range wavelength, red range wavelength, and infrared range wavelength or around such wavelengths. In other examples, the waveguide may be similar to a hollow tube and internally reflect light in the green range wavelength, red range wavelength, and infrared range wavelength or around such wavelengths. Figure 7 The waveguide of Figure 7 may be optically coupled to the emitter and the detector via butt coupling, one or more prisms, one or more lenses, and / or any other suitable method, or any combination thereof. Additionally, Figure 7 The waveguide of Figure 7 may be of any suitable shape, such as a sheet or film, a cable, a straight line, a taper, any combination thereof, etc. In some examples, the far waveguide 785 may extend through the back cover of the wearable device, and the back cover may not include a window.

[0135] In Figure 7 In other examples of Figure 7 , the back cover may have an opening but no optically transparent window. Instead, the waveguide may fill the opening in the back cover. In this example, the waveguide may directly receive reflected light and / or backscattered light that has passed through the arterial and venous blood flow of a person. The waveguide may be plastic, glass, hardened glass, a solid rod, a hollow tube, or any other suitable configuration or material, or any combination thereof. In some examples, the waveguide may be an optical fiber waveguide, such optical fiber waveguides may be similar to solid plastic rods having internal solid reflective materials that reflect light in the green wavelength, red wavelength, and infrared wavelength or around such wavelengths. In other examples, the optical fiber waveguide may be similar to a hollow plastic tube through which light can propagate through air, but the inner peripheral wall of the hollow plastic tube may be a reflective material that reflects light in the range of the green wavelength, red wavelength, and infrared wavelength or around such wavelengths.

[0136] The emitter waveguide 775, the near waveguide 780, and the far waveguide 785 may be optical waveguides, including but not limited to, fiber optic devices, single mode, step index, gradient index, light guides, planar, membranes, any combination thereof, etc. In some examples, the emitter waveguide 775, the near waveguide 780, and the far waveguide 785 may be different types of waveguides from each other. The waveguides may be inserted into holes or openings machined into the back cover 707. The emitter waveguide 775 may ensure that the emitted light is transmitted towards the tissue and not directly towards the near detector 730 or the far detector 735. In some examples, each individual emitter of the emitter 705 may have a corresponding waveguide. For example, a red light emitter may have a waveguide, an infrared light emitter may have a waveguide, and a green light emitter may have a waveguide. In additional examples, the near detector 730 and the far detector 735 may not have waveguides associated with the detectors, as discussed with respect to Figures 5A to 5D and Figures 6A to 6C discussed.

[0137] In some examples, the emitter waveguide 775, the near waveguide 780, and the far waveguide 785 may have an inner core that reflects wavelengths around green, infrared, and red light. Further, the core of the waveguide may minimally absorb around these wavelengths such that the maximum amount of emitted light can be transmitted to the wrist tissue of the user wearing the wearable device and not be absorbed by the waveguide. Additionally, the inner core of the waveguide may minimally absorb around these wavelengths such that light reflected off and / or backscattered from the wrist tissue can be detected by the near detector 730 and the far detector 735.

[0138] Figures 8A to 8D Various layouts 800, 805, 806, and 809 of the back cover of the wearable device are shown. The window of the back cover 807 in any of the layouts 800 described with reference to Figures 8A to 8D in any of those described may be configured in some examples such that a first set of windows may be configured to transmit the emitted light to the user's wrist and such that a second set of windows may be configured to detect light reflected off the user's arterial blood flow and / or backscattered light that has passed through the arterial blood. Additionally, the layout 800 may be used in any of the examples described with respect to Figures 1A to 7 described. The back cover and / or the windows in each layout may be formed of sapphire, glass, plastic, or other materials.

[0139] Figure 8A An example 800 of the back cover of the wearable device is shown. In some examples, the back cover 807 may be incorporated into the wearable device to provide physiological and / or biometric measurements of the user wearing the wearable device, as discussed with respect to Figures 1A to 7 discussed. As Figure 8AAs shown, the back cover 807 may include six windows disposed around a central portion (or central window) as described herein. Figure 8A The windows of the back cover 807 in Figures 5A to 5D may be circular and may provide nine optical paths between the emitter and the detector, and may be used in conjunction with any of the protrusion embodiments discussed with respect to Figures 6A to 6C the frit embodiments discussed with respect to Figure 7 the waveguide embodiments discussed with respect to Figure 8A In Figure 8A the emission region may be defined by the inner diameter of the frit or by the distance between the inner edges of the protrusions as discussed herein. Although the windows may be larger, the aperture through which light can pass may be determined by the optical barrier between the emitter and the detector. In Figure 8A other examples of

[0140] Figure 8B Example 803 of a back cover of a wearable device is shown. In some examples, the back cover 807 may be incorporated into the wearable device to provide physiological and / or biometric measurements of a user wearing the wearable device, as discussed with respect to Figures 1A to 8A As Figure 8B shown, the back cover 807 may include eight windows as described in detail herein. Figure 8B The windows of the back cover 807 in Figure 8B may be rectangular and triangular in shape and may provide sixteen optical paths between the emitter and the detector, and in some examples, may provide up to sixteen optical paths between the emitter and the detector. Figures 5A to 5D Examples of Figures 6A to 6C may be used in conjunction with any of the protrusion embodiments discussed with respect to Figure 7 the frit embodiments discussed with respect to Figure 8B the waveguide embodiments discussed with respect to Figure 8B In

[0141] Figure 8C Example 806 of a back cover of a wearable device is shown. In some examples, the back cover 807 may be incorporated into the wearable device to provide physiological and / or biometric measurements of a user wearing the wearable device, as discussed with respect to Figures 1A to 8B As Figure 8C shown, the back cover 807 may include eight windows as described in detail herein. Figure 8CThe window of the back cover 807 therein can be circular and can provide sixteen optical paths between the emitter and the detector. Figure 8C Examples of Figures 5A to 5D can be used in conjunction with the convex portion embodiments discussed with respect to Figures 6A to 6C the frit embodiments discussed with respect to Figure 7 or any of the waveguide embodiments discussed with respect to

[0142] In Figure 8C , light can be detected through the window 850 after reflecting off the wrist artery. The window 850 can include an optical barrier (e.g., a convex portion, ink, film, coating, surface treatment, or frit, as described with reference to Figures 1B to 7 ) that extends through the back cover 807 and surrounds (or defines) the inner diameter of the window. Although all apertures can be the same size in Figure 8C , the window 845 through which the emitted light can pass may not have an optical barrier extending through the back cover 807 (but it may). Instead, the window 845 can be integrated with the back cover 807 (i.e., the window 845 may not be an insert window) and have a diameter defined by other portions of the inner or outer surface of the back cover 807 where no optical shielding (e.g., ink (optically opaque ink), film, coating, or surface treatment) is applied. For example, the optical shielding can be on a first portion (e.g., the non-window portion) of the back cover 807 and not on a second portion of the back cover 807. The optical shielding can define the size of the aperture above each emitter, but may not be able to block light from being redirected within the back cover 807. However, the emitted light that is redirected within the back cover 807 but does not exit the back cover 807 can be blocked from reaching the detector by an optical barrier that extends through the back cover 807 and surrounds the detector window. The optical barrier can be formed by one or more of ink, film, coating, surface treatment, or frit disposed between the window and its corresponding opening, which in some cases can be completely or partially surrounded by stepped or tapered convex portions. In the case of ink, film, coating, or surface treatment, the ink, film, coating, or surface treatment can be formed on or applied to the window or opening (or convex portion) before adjoining and attaching the window to the opening (or convex portion). The window 850 can be larger than the window 845, but the aperture of the window 850 and the aperture of the window 850 can be the same size. In some examples, the window 850 can include an optical barrier, e.g., a convex portion or frit, which can result in an aperture smaller than the window 850.

[0143] Figure 8D An example 809 of the back cover of a wearable device is shown. In some examples, the back cover 807 can be incorporated into the wearable device to provide physiological and / or biometric measurements of the user wearing the wearable device, as discussed with respect to Figures 1A to 8C . As Figure 8D shown, the back cover 807 can include eight windows as described in detail herein.Figure 8D The window of the back cover 807 in can be rectangular and circular in shape and can provide sixteen optical paths between the emitter and the detector. Figure 8D Examples of can be related to Figures 5A to 5D the convex portion implementation discussed in , related to Figures 6A to 6C the frit implementation discussed in , or related to Figure 7 the waveguide implementation discussed in . In , the shape of the window and aperture can be implemented to maximize the use of the surface area of the back cover 807 as much as possible. Further, in Figure 8D the emitter can be linear in shape to use as many aperture openings as possible. In an implementation using a linear-shaped emitter, the emitter can emit stronger or denser light for transmission into the user's wrist tissue. In other examples, Figure 8D the window of the back cover 807 in can provide up to sixteen optical paths between the emitter and the detector. Figure 8D In , the window of the back cover 807 can provide up to sixteen optical paths between the emitter and the detector.

[0144] Figure 9A and Figure 9B show various layouts for the back cover of a wearable device. In the layouts 900 and 913 described with reference to both FIGS. 9 and Figure 10 the window of the back cover shown can be configured in some examples such that the window can be configured to transmit the emitted light to the user's wrist and can further be configured to detect the light reflected off the user's arterial blood flow and / or the backscattered light that has passed through the arterial blood. Additionally, the layout can be used in any of the examples described in Figures 1A to 8D related to .

[0145] Figure 9A FIG. shows the layout 900 of the back cover of a wearable device. In some examples, the back cover 907 can be incorporated into the wearable device to provide physiological and / or biometric measurements of the user wearing the wearable device, as discussed in Figures 1A to 8D related to . As shown in Figure 9A the back cover 907 can include six windows disposed around the central portion (or central window) of the back cover 907, similar to Figure 8A and can provide nine optical paths between the emitter and the detector. In Figure 9A other examples of , the back cover 907 can be similar to Figure 8A include six windows and can provide up to nine optical paths between the emitter and the detector. Figure 9A The window of the back cover 907 in can be circular in shape. The window can alternatively have alternating shapes or sizes and can be more or fewer in number.

[0146] As shown in Figure 9A ​​​​​​​​​​As shown, the green light emitter 905a of the emitter 905 can emit green light. The green light can be transmitted from the green light emitter and can be reflected off arterial blood flow and detected by detectors 925 and 930. Figure 9A The light reflected off the blood vessel is depicted as being stronger or of a higher magnitude at some locations and weaker or of a lower magnitude at other locations. Due to the circular layout and circular shape of the windows and apertures, only a portion of the reflected green light can be aligned with the detectors. While the signal can provide useful information, it is desirable for the detectors to detect as much of the reflected light as possible, as opposed to only detecting a portion of the reflected light at the periphery of the detectors.

[0147] Figure 9B The layout 913 of the back cover of the wearable device is shown. In some examples, the back cover 907 can be incorporated into the wearable device to provide physiological and / or biometric measurements of the user wearing the wearable device, as discussed Figures 1A to 8D as Figure 9B shown, the back cover 907 can include eight windows similar to the Figure 8B layout and can provide sixteen optical paths between the emitter and the detectors. In Figure 9B other examples, the back cover 907 can include eight windows and can provide up to sixteen optical paths between the emitter and the detectors. Figure 9B The windows of the back cover 907 in

[0148] as Figure 9B shown, the green light emitter 905a of the emitter 905 can emit green light and, as previously discussed, can be positioned within the inner portion of the triangular windows and apertures. The green light can be transmitted from the green light emitter and can be reflected off arterial blood flow and detected by detectors 925 and 930. Figure 9B The light reflected off the blood vessel is depicted as being stronger or of a higher magnitude at some locations and weaker or of a lower magnitude at other locations. Due to the circular layout and rectangular shape of the windows and apertures of detectors 925 and 930, the reflected green light can "lineup" or overlap with most to all of the detection area of detectors 925 and 930. As opposed to detecting the reflected light at the periphery of the detectors as described Figure 9A in

[0149] Figures 1A to 9B The described layout and configuration of the wearable device in

[0150] In various embodiments, a component or an ink is referred to as "opaque" or "optically opaque". The component or ink is generally optically opaque to the wavelengths of the emitted or received electromagnetic radiation of the underlying component, or is optically opaque to a range of wavelengths of the emitted or received electromagnetic radiation, and can thus block the (multiple) wavelengths. In some cases, the component or ink can also be optically opaque to other or all wavelengths of the electromagnetic radiation, or block other or all wavelengths of the electromagnetic radiation. In some cases, the component or ink can also be optically opaque to visible light for aesthetic and / or other reasons.

[0151] In various embodiments, a component or an ink is referred to as "transparent" or "optically transparent". The component or ink can be optically transparent only to the wavelengths of the emitted or received electromagnetic radiation of the underlying component, or is optically transparent to a range of wavelengths of the emitted or received electromagnetic radiation, and can thus transmit the (multiple) wavelengths. In some cases, the component or ink can also be optically transparent to other or all wavelengths of the electromagnetic radiation, or transmit other or all wavelengths of the electromagnetic radiation.

[0152] In some embodiments, the inks described herein can alternatively be or include one or more of coatings, surface treatments, etc. In some embodiments, multiple inks, coatings, or surface treatments can be combined to provide optical blocking and / or optical transparency for one or more bands.

[0153] In some embodiments, opaque, selectively opaque, and / or selectively transparent components, inks, coatings, surface treatments, or the like can be used to reduce unwanted optical crosstalk between a transmitter and a receiver, or between different optical paths.

[0154] Figure 10 A sample electrical block diagram of an electronic device 1000 is shown, and the electronic device can be the electronic device described with reference to Figures 1A to 9B The electronic device 1000 can include a display 1002 (e.g., a light-emitting display on the front side of a wearable device), a processor 1004, a power supply 1006, a memory 1008 or storage device, a sensor system 1010, and an input / output (I / O) mechanism 1012 (e.g., an input / output device and / or an input / output port). The processor 1004 can control some or all of the operations of the electronic device 1000. The processor 1004 can communicate directly or indirectly with substantially all components of the electronic device 1000. For example, a system bus or other communication mechanism 1014 can provide communication between the processor 1004, the power supply 1006, the memory 1008, the sensor system 1010, and / or the I / O mechanism 1012.

[0155] The processor 1004 can be implemented as any electronic device capable of processing, receiving, or sending data or instructions. For example, the processor 1004 can be a microprocessor, a central processing unit (CPU), an application-specific integrated circuit (ASIC), a digital signal processor (DSP), or a combination of such devices. As described herein, the term "processor" is meant to encompass a single processor or processing unit, multiple processors, multiple processing units, or other appropriately configured operative software.

[0156] It should be noted that the components of the electronic device 1000 can be controlled by multiple processors. For example, select components of the electronic device 1000 can be controlled by a first processor, and other components of the electronic device 1000 can be controlled by a second processor, where the first and second processors may or may not communicate with each other. In some embodiments, the processor 1004 can include any of the processors described herein and / or any that may be capable of performing the processing steps described herein.

[0157] The power supply 1006 can be implemented by any device capable of providing energy to the electronic device 1000. For example, the power supply 1006 can be one or more batteries or rechargeable batteries. Additionally or alternatively, the power supply 1006 can be a power connector or power line that connects the electronic device 1000 to another power source (such as a wall outlet).

[0158] The memory 1008 can store electronic data that can be used by the electronic device 1000. For example, the memory 1008 can store electrical data or content, such as, for example, audio and video files, documents and applications, device settings and user preferences, timing signals, control signals, data structures or databases, image data, biometric data, or focus settings. The memory 1008 can be configured as any type of memory. By way of example only, the memory 1008 can be implemented as random access memory, read-only memory, flash memory, removable memory, other types of storage components, or a combination of such devices.

[0159] The electronic device 1000 may also include a sensor system 1010, which in turn includes one or more sensors substantially located at any position on the electronic device 1000 (e.g., the back side of a wearable device). The (multiple) sensors may be configured to substantially sense any type of characteristic, such as but not limited to, pressure, electromagnetic radiation (light), touch, heat, movement, relative movement, biometric data, etc. For example, the (multiple) sensors may include thermal sensors, position sensors, light or optical sensors, accelerometers, pressure transducers, gyroscopes, magnetometers, health monitoring sensors, etc. Additionally, one or more sensors may utilize any suitable sensing technology, including but not limited to, capacitive, ultrasonic, resistive, optical, ultrasonic, piezoelectric, and thermal sensing technologies.

[0160] The I / O mechanism 1012 may transmit and / or receive data from a user or another electronic device. The I / O device may include a display, a touch-sensing input surface (such as a trackpad), one or more buttons (e.g., a graphical user interface "home" button), one or more cameras, one or more transmitters and / or detectors (e.g., a wearable device having a biometric sensor as described herein with reference Figures 1A to 9B to), one or more microphones or speakers, one or more ports (such as a microphone port), and / or a keyboard. Additionally or alternatively, the I / O device or port may transmit an electronic signal via a communication network (such as a wireless and / or wired network connection). Examples of wireless and wired network connections include but are not limited to, cellular, Wi-Fi, Bluetooth, IR, and Ethernet connections.

[0161] For purposes of explanation, the foregoing description uses specific nomenclature to provide a thorough understanding of the described embodiments. However, after reading this description, those skilled in the art will appreciate that specific details are not necessary for practicing the described embodiments. Therefore, the foregoing description of the specific embodiments presented herein is for purposes of illustration and description. The above embodiments are not intended to be exhaustive or to limit the embodiments to the precise forms disclosed. After reading this description, those skilled in the art will appreciate that many modifications and variations are possible in light of the above teachings, and various features of the example embodiments may be combined for use in a particular application.

[0162] This disclosure recognizes that personal information data (including biometric data obtained using the techniques described herein) can be used to benefit the user. For example, the use of biometric authentication data can be used to conveniently access device functions without using a password. In other examples, user biometric data is collected to provide feedback to the user related to their health or fitness level. Further, this disclosure also contemplates other uses of personal information data (including biometric data) that benefit the user.

[0163] The present disclosure further contemplates that the entity responsible for the collection, analysis, disclosure, transmission, storage, or other use of such personal information data will comply with well-developed privacy policies and / or privacy practices. Specifically, such entity should implement and consistently use privacy policies and privacy practices generally recognized as meeting or exceeding industry or government requirements for maintaining the privacy and security of personal information data, including the use of data encryption and security methods that meet or exceed industry or government standards. For example, personal information from users should be collected for the legitimate and reasonable use of the entity and not shared or sold beyond such legitimate use. Further, such collection should only occur after receiving the informed consent of the user. In addition, such entity will take any necessary steps to secure and protect access to such personal information data and ensure that others with access to the personal information data comply with its privacy policies and procedures. Further, the entity itself may be evaluated by a third party to certify that the entity complies with widely accepted privacy policies and privacy practices.

[0164] Notwithstanding the foregoing, the present disclosure also contemplates embodiments where users may selectively block the use or access to personal information data (including biometric data). That is, the present disclosure contemplates that hardware and / or software components may be provided to prevent or block access to such personal information data. For example, in the case of biometric authentication methods, the technology may be configured to allow users to optionally skip the biometric authentication step by providing security information (provided alone or in combination, such as passwords, personal identification numbers (PINs), touch gestures, or other authentication methods known to those skilled in the art). In another example, users may choose to remove, deactivate, or limit access to certain health-related applications that collect the users' personal health or fitness data.

Claims

1. A wearable device, comprising: a housing having a back cover; the back cover includes a set of windows arranged around a central portion of the back cover, wherein: a first subset of windows has a first shape; a second subset of windows has a second shape different from the first shape; and the first subset of windows alternates with the second subset of windows; a first set of optical barriers surrounding each window in the second subset of windows; a set of light emitters configured to emit light through each window in the first subset of windows; and a set of light detectors configured to receive light passing through each window in the second subset of windows.

2. The wearable device according to claim 1, wherein: the first shape is a rectangular shape; and the second shape is a circular shape.

3. The wearable device according to claim 1, wherein: the first shape is a triangular shape; and the second shape is a rectangular shape.

4. The wearable device according to any one of claims 1-3, further comprising: a second set of optical barriers surrounding each window in the first subset of windows.

5. The wearable device according to any one of claims 1-3, wherein: the set of light emitters includes a corresponding subset of light emitters for each window in the first subset of windows; and each corresponding subset of light emitters includes an infrared light emitter and a red light emitter.

6. The wearable device according to claim 5, wherein: each corresponding subset of light emitters includes a green light emitter.

7. The wearable device according to claim 5, comprising: a processor configured to: operate the set of emitters; receive an indicator of the amount of at least red light range wavelengths and infrared light range wavelengths detected by the set of light detectors; and determine an oxygenation level using at least a subset of the indicators.

8. The wearable device according to claim 1, wherein the respective optical barriers in the first set of optical barriers surrounding the windows in the second subset of windows include at least one of an ink, a film, a coating, or a surface treatment disposed between the windows in the second subset of windows and corresponding openings in the back cover.

9. The wearable device according to claim 8, wherein: the back cover includes a stepped protrusion extending partially or completely around each opening in the back cover; and each window in the second subset of windows abuts the stepped protrusion extending partially or completely around the corresponding opening in the back cover.

10. The wearable device according to claim 8, wherein: the back cover includes a tapered protrusion extending partially or completely around each opening in the back cover; and each window in the second subset of windows abuts the tapered protrusion extending partially or completely around the corresponding opening in the back cover.

11. A wearable device, comprising: a housing having a back cover; an optical shield on a first portion of the back cover; the back cover includes a set of windows positioned around a central portion of the back cover, wherein: The first subset of windows in the set of windows is defined by the second portion of the back cover where there is no such optical shield; and The second subset of windows in the set of windows is inserted into a set of openings in the back cover, where the windows of the second subset of windows are arranged to alternate with the windows of the first subset of windows; An optical barrier that surrounds each window in the second subset of windows; A set of light emitters configured to emit light through at least some of the windows in the set of windows; and A set of light detectors configured to receive light passing through the second subset of windows.

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