Concentric structures for optical sensing

Abstract

This document relates to concentric structures for optical sensing. An electronic device including optical sensing having a concentric structure and a method of operating the same. The concentric structure may include light detectors arranged in a concentric manner around a light emitter. In some examples, at least one light emitter may be located at the center of the device, and each light detector may be located at the same spacing distance from the light emitter. Each light detector may be arranged so that the spacing distance from the centrally located light emitter is greater than the spacing distance from another light emitter. Examples of the present disclosure also include a selectively transparent layer covering the light detectors. The selectively transparent layer may include a region that is transparent to a first wavelength range and opaque to a second wavelength range. In some examples, the selectively transparent layer may also include a region that is transparent to the second wavelength range.

Description

[0001] This application is a divisional application of the Chinese patent application with international application number PCT / US2018 / 050300, international application date September 10, 2018, national application number 201880055939.4, and invention name “Concentric structure for optical sensing”. Technical Field

[0002] The present disclosure generally relates to structures for optical sensing. More particularly, the present disclosure relates to structures for an optical sensing unit that includes a plurality of light detectors arranged concentrically around a plurality of light emitters. Background Art

[0003] Photoplethysmography (PPG) signals can be measured by an optical sensing system to derive corresponding physiological signals (e.g., pulse rate). In a basic form, the optical sensing system may employ a light emitter that transmits light through a hole and / or window into the user's tissue. Furthermore, a light detector may be included to receive light through the hole and / or window. The light received by the light detector may be light that has returned (e.g., reflected or scattered) and exited the tissue. In some cases, optical losses due to one or more components in the system may affect the determination of the user's physiological information. Summary of the Invention

[0004] The present disclosure relates to an electronic device configured for optical sensing with a concentric structure and a method of operating the same. The concentric structure may include a plurality of light detectors arranged in a concentric manner around a plurality of light emitters. The plurality of light emitters may include a plurality of first light emitters that emit in a first wavelength range (e.g., visible wavelengths) and one or more second light emitters that emit in a second wavelength range (e.g., infrared wavelengths). In some examples, at least one second light emitter may be located at the center of the device, and each light detector may be positioned at the same spacing distance from the at least one second light emitter. Each light detector may be arranged so that the spacing distance from the centrally located second light emitter may be greater than the spacing distance from the first light emitter.

[0005] Examples of the present disclosure also include a selectively transparent layer covering the multiple light detectors. The selectively transparent layer may include multiple first regions that are transparent to a second wavelength range (e.g., infrared wavelengths) and opaque to a first wavelength range (e.g., visible wavelengths). The selectively transparent layer may also include multiple second regions that are transparent to the second wavelength range. In some examples, a Fresnel lens may be located in corresponding regions of the first light emitter and the second light emitter. The Fresnel lens may include multiple regions, such as a first region and a second region. The first region may be located in the field of view of the first light emitter, and the second region may be located in the field of view of the second light emitter. The multiple regions of the Fresnel lens may have different optical (e.g., percentage of transmission, amount of collimation, etc.) characteristics.

[0006] A method for operating an optical sensing unit may include associating the plurality of light detectors to one or more channels. Each light emitter is sequentially activated to emit light, and the one or more channels may also sequentially measure the light from a given light emitter. In some examples, the association of the one or more channels may be dynamically changed. For example, during a first time period, all of the plurality of light detectors may be associated with a single channel. The system may dynamically change the association of the plurality of light detectors to multiple channels during a second time period. In some examples, the device may be configured to perform multiple measurement types (e.g., a primary measurement and a secondary measurement) as part of a sampling process, wherein the primary measurement may include a reading utilizing a first set of operating conditions of the PPG sensor unit, and the secondary measurement may utilize another second set of operating conditions of the PPG sensor unit. For example, the single channel may be used for the primary measurement, while the multiple channels may be used for the secondary measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1A-1C A system is shown in which examples of the present disclosure may be implemented.

[0008] Figure 2A A top view of an exemplary electronic device including concentric structures for optical sensing according to examples of the present disclosure is shown.

[0009] Figure 2B Shown is an example according to the present disclosure Figure 2A Cross-sectional view along line I-II.

[0010] Figure 2C A top view of an exemplary concentric structure including a selective transparent layer covering according to an example of the present disclosure is shown.

[0011] Figure 2D Shown is a magnified view of an exemplary selectively transparent layer covering a single photodetector according to examples of the present disclosure.

[0012] Figure 2EA cross-sectional view of an exemplary electronic device including concentric structures and a retroreflector according to examples of the present disclosure is shown.

[0013] Figure 2F A cross-sectional view of an exemplary electronic device including concentric structures, a retroreflector, and an opaque mask according to examples of the present disclosure is shown.

[0014] Figure 2G-2H A cross-sectional view and a top view, respectively, are shown of an exemplary electronic device including a lens having multiple regions according to examples of the present disclosure.

[0015] Figure 3 An exemplary process of using a merging technique for one or more channels according to an example of the present disclosure is shown.

[0016] Figures 4A-4E An exemplary association of light detectors with channels according to examples of the present disclosure is shown.

[0017] Figure 5 An exemplary block diagram of a computing system including a light emitter and a light detector for measuring a signal associated with a physiological state of a user according to an example of the present disclosure is shown.

[0018] Figure 6 An exemplary configuration in which an electronic device according to an example of the present disclosure is connected to a host is shown. DETAILED DESCRIPTION

[0019] In the following description of the examples, the accompanying drawings will be referenced, in which specific examples that can be implemented are shown in an illustrative manner. It should be understood that other examples can be used and structural changes can be made without departing from the scope of each example. Many specific details are set forth in order to provide a thorough understanding of one or more aspects and / or features described or quoted herein. However, it will be apparent to those skilled in the art that one or more aspects and / or features described or quoted herein can be implemented without some or all of these specific details. In other cases, well-known process steps and / or structures are not described in detail so as not to obscure some of the aspects and / or features described or quoted herein.

[0020] Photoplethysmography (PPG) signals can be measured by an optical sensing system to derive corresponding physiological signals (e.g., pulse rate). Such optical sensing systems can be designed to be sensitive to changes in the user's tissue, which can be caused by fluctuations in the amount or volume of blood or blood oxygen in the user's vasculature. In a basic form, the optical sensing system can employ a light emitter that transmits light into the user's tissue through a hole and / or window. The system can also include a light detector for receiving return light (i.e., light that has been reflected and / or scattered and leaves the tissue) through the same or another hole and / or window. The PPG signal is the amplitude of the return light modulated by the volumetric change of the blood volume in the tissue. The light emitter and light transmitter in the optical sensing system can be arranged in a concentric configuration.

[0021] The present disclosure relates to an electronic device configured for optical sensing with a concentric structure and a method of operating the same. The concentric structure may include a plurality of light detectors arranged in a concentric manner around a plurality of light emitters. The plurality of light emitters may include a plurality of first light emitters that emit in a first wavelength range (e.g., visible wavelengths) and one or more second light emitters that emit in a second wavelength range (e.g., infrared wavelengths). In some examples, at least one second light emitter may be located at the center of the device, and each light detector may be positioned at the same spacing distance from the at least one second light emitter. Each light detector may be arranged so that the spacing distance from the centrally located second light emitter may be greater than the spacing distance from the first light emitter.

[0022] Examples of the present disclosure also include a selectively transparent layer covering the multiple light detectors. The selectively transparent layer may include a plurality of first regions that are transparent to a second wavelength range (e.g., infrared wavelengths) and at least partially opaque to a first wavelength range (e.g., visible wavelengths). The selectively transparent layer may also include a plurality of second regions that are transparent to the second wavelength range. In some examples, a Fresnel lens may be located in respective regions of the first light emitter and the second light emitter. The Fresnel lens may include a plurality of regions, such as a first region and a second region. The first region may be located in the field of view of the first light emitter, and the second region may be located in the field of view of the second light emitter. The plurality of regions of the Fresnel lens may have different optical (e.g., percentage of transmission, amount of collimation, etc.) characteristics.

[0023] A method for operating an optical sensing unit may include associating the plurality of light detectors to one or more channels. Each light emitter is sequentially activated to emit light, and the one or more channels may also sequentially measure the light from a given light emitter. In some examples, the association of the one or more channels may be dynamically changed. For example, during a first time period, all of the plurality of light detectors may be associated with a single channel. The system may dynamically change the association of the plurality of light detectors to multiple channels during a second time period. In some examples, the device may be configured to perform multiple measurement types (e.g., a primary measurement and a secondary measurement) as part of a sampling process, wherein the primary measurement may include a reading utilizing a first set of operating conditions of the PPG sensor unit, and the secondary measurement may utilize another second set of operating conditions of the PPG sensor unit. For example, the single channel may be used for the primary measurement, while the multiple channels may be used for the secondary measurement.

[0024] This section describes representative applications of the apparatus and methods of the present disclosure. These examples are provided solely to add context and aid in understanding the examples. Therefore, it will be apparent to those skilled in the art that the examples may be practiced without some or all of the specific details. Other applications are possible, such that the following examples should not be considered limiting.

[0025] Figure 1A-1C A system is shown in which examples of the present disclosure may be implemented. Figure 1A An exemplary mobile phone 136 is shown that may include a touch screen 124 . Figure 1B An exemplary media player 140 is shown that may include a touch screen 126 . Figure 1C An exemplary wearable device 144 is shown that may include a touch screen 128 and may be attached to a user using a strap 146 . Figure 1A-1C The system may utilize optical layers, optical films, lenses, window systems, concentric structures, and / or methods for detecting PPG signals, as will be disclosed.

[0026] Exemplary Configuration of Optical Sensing Unit

[0027] Figure 2A A top view of an exemplary electronic device including a concentric structure for optical sensing according to an example of the present disclosure is shown. For example, Figure 2A The top view in the Figure 1C The underside of the wearable device 144. In addition, Figure 2A The top view in FIG. 1 includes a partial top view of the device without the optional transparent layer (discussed below) covering it.

[0028] The device 200 may include a plurality of light detectors 204A, 204B, 204C, 204D, 204E, 204F, 204G, and 204H (collectively, the plurality of light detectors 204); a plurality of first light emitters 206A, 206B, 206C, and 206D (collectively, the plurality of first light emitters 206); and a plurality of second light emitters 208A and 208B (collectively, the plurality of second light emitters 208). The device 200 may be positioned such that the plurality of light detectors 204, the plurality of first light emitters 206, and the plurality of second light emitters 208 are adjacent to the user's skin. For example, the device 200 may be held in the user's hand or strapped to the user's wrist, among other possibilities.

[0029] The device may include multiple regions, such as a central region 209 and a peripheral region 205. The central region 209 may be separated from the peripheral region 205 by an optical isolator (e.g., optical isolator 216), wherein the peripheral region 205 may be positioned closer to an edge of the device 200 (e.g., edge 201C) than the central region 209. For example, the central region 209 may include a plurality of light emitters (e.g., first light emitters 206 and second light emitters 208). In some examples, the plurality of first light emitters 206 may be positioned closer to the peripheral region than at least one second light emitter 208 (e.g., second light emitter 208A). In some examples, the at least one second light emitter 208 (e.g., second light emitter 208A) may be located at the center of the central region 209. In some examples, the plurality of first light emitters 206 may be configured to emit a different range of wavelengths (e.g., green wavelengths) than the second light emitters 208 (e.g., the second light emitters may be configured to emit infrared wavelengths). The peripheral region 205 may partially or completely surround the central region 209 .

[0030] In some examples, the spacing and positions of the light detectors and light emitters can be optimized for different types of measurements (e.g., primary and secondary measurements). For example, the second light emitter 208A can be located at the center of the device 200 and can be configured to emit infrared light for detecting one type of information. The center of the device 200 can be such that the distance from the second light emitter 208A to the edges of the device 200 along the same direction (e.g., from left to right and / or from top to bottom) is the same. For example, the distance from the top edge 201A of the device to the second light emitter 208A can be the same as the distance from the bottom edge 201B of the device. The distance from the left edge 201C of the device to the second light emitter 208A can be the same as the distance from the right edge 201D of the device. Optionally, the device 200 can include a second light emitter 208B that is also used to detect the same type of information as the second light emitter 208A.

[0031] The plurality of first light emitters 206 may be positioned closer to the peripheral area 205. For example, the plurality of first light emitters 206 may include four light emitters: a first light emitter 206A, a first light emitter 206B, a first light emitter 206C, and a first light emitter 206D, which may be arranged to form a square, a rectangle, a quadrilateral, or the like. For example, the plurality of first light emitters 206 may be arranged in a square, wherein the spacing distance between the first light emitter 206A and the first light emitter 206B, the spacing distance between the first light emitter 206B and the first light emitter 206C, the spacing distance between the first light emitter 206C and the first light emitter 206D, and the spacing distance between the first light emitter 206D and the first light emitter 206A may be the same. In some examples, the spacing distance between each first light emitter 206 and the central second light emitter 208A may be the same. While the figure illustrates the plurality of first light emitters 206 as being positioned at the same spacing distance from the optical isolator 216, examples of the present disclosure may include light emitters spaced at different distances. Furthermore, examples of the present disclosure are not limited to light emitters positioned in a similar square arrangement, and pairs of first and second light emitters are not limited to having the same spacing distance.

[0032] The peripheral region 205 may be positioned (partially or completely) around the central region 209. The plurality of light detectors 204 may be radially arranged in the peripheral region 205. In some examples, the radial arrangement may include the plurality of light detectors 204 being oriented at a given edge angle depending on their position in the peripheral region 205, wherein each light detector 204 has the same or similar shape. For example, the angle of the top edge 214 of light detector 204A and light detector 204E (e.g., the edge of the light detector closest to the edge of the device) may be 0°. The top edge 214 of light detector 204B and / or light detector 204F may be 45° relative to the top edge 214 of light detector 204A and / or light detector 204E. The top edge 214 of light detector 204D and / or light detector 204H may be -45° relative to the top edge 214 of light detector 204A and / or light detector 204E. The top edge 214 of the light detector 204C and / or the light detector 204G may be 90° or -90° relative to the top edge 214 of the light detector 204A and / or the light detector 204E. In this way, the top edges 214 of two or more light detectors 204 may have different orientation angles.

[0033] The relative arrangement of the light emitters and light detectors can be such that the distance between a first light emitter 206 (e.g., first light emitter 206A) and its nearest light detector 204 (e.g., light detector 204A) (i.e., separation distance D2) can be less than the distance between a second light emitter 208 (e.g., second light emitter 208A) and the same light detector 204 (i.e., separation distance D1). In an example, the first light emitter 206A can be an LED that emits visible light (e.g., green light) and has a separation distance D2 from one light detector 204A that is shorter than the separation distances from other light detectors, such as light detectors 204B-204H. The term "separation distance" refers to the distance measured from the center of one component to the center of another component. In some examples, the separation distances between a first light emitter 206 and its nearest neighboring light detector 204 can be the same. Additionally, the distance (eg, separation distance D3) between the same nearest first light emitter 206 (eg, first light emitter 206A) and another light detector (eg, light detector 204E) may be greater than both separation distance D1 and separation distance D2, as shown.

[0034] In some examples, second light emitter 208A can be an infrared light emitter configured for one type of measurement, and first light emitter 206A can be a visible (e.g., green wavelength) light emitter configured for another type of measurement. In some examples, the light detectors associated with separation distance D1 and separation distance D3 can have the same orientation angle. For example, light detector 204A and light detector 204E can each have a top edge 214 oriented at 0°.

[0035] In some examples, each light detector can be configured so that its edges are "aligned" with the light emitters. For example, the center of the first light emitter 206A can be along the same y-plane as the center of the light detector 204A. In this way, the separation distance D2 between the center of a first light emitter (e.g., first light emitter 206A) and its nearest light detector (e.g., light detector 204A) is less than the separation distances between the center of the same first light emitter and other light detectors in the plurality of light detectors 204.

[0036] In other examples, the first light emitter 206A may be located between the edges of adjacent light detectors 204A and 204H, such as Figure 2CAs shown. That is, the radial angle of the first light emitter 206A can be the same as the radial angle of the edge of the light detector 204A and the light detector 204H. In this way, the separation distance between the center of the light emitter (e.g., the first light emitter 206A) and the center of its two nearest light detectors (e.g., light detectors 204A and 204H and / or two adjacent light detectors) can be the same. Although the figure shows eight light detectors 204 and four first light emitters 206, examples of the present disclosure may include any number of light detectors and any number of light emitters. In addition, although the figure illustrates the light detector 204 as having a rectangular-shaped detection area and the light emitter as having a square-shaped emission area, examples of the present disclosure may include any shape.

[0037] Device 200 may include one or more components for achieving enhanced optical collection, signal generation, and / or reduced noise. Figure 2B Shown Figure 2A Cross-sectional view along line I-II. The one or more components may include an optical isolator 216, an optical film 240, and a Fresnel lens 242. To prevent or reduce optical crosstalk between the plurality of light detectors 204 and the plurality of first light emitters 206, the optical isolator 216 may be a wall located between the plurality of light detectors 204 and the plurality of first light emitters 206. Thus, the optical isolator 216 may define a cavity for the light emitters, separate from the cavity for the light detectors. The optical isolator 216 may be located in the central region 209 and / or in the peripheral region 205. In some examples, the optical isolator 216 located in the central region 209 may include the same material (or be formed from a continuous piece of material) as the optical isolator 216 located in the peripheral region 205. In some cases, the optical isolator 216 may be concentric rings. In some examples, the optical isolator 216 may be different from other types of isolators that may be included in the device. The optical isolator 216 may form at least two cavities in total in which the light emitters and light sensors may be located. Other types of isolation may include, but are not limited to, optical, electrical, and / or mechanical isolation of the optical sensing system from other components included in the device (eg, a display or touch screen).

[0038] The optical film 240 may be a film configured for light confinement (discussed in detail below). The optical film 240 may at least partially cover a portion of the window 203 corresponding to the light passing through to reach the at least one light detector 204. In some examples, the device 200 may include a portion of the optical film 240 disposed above each light detector 204. The optical film 240 may have other arrangements, such as attached to the window, disposed on the window, disposed on the detector, etc. In some examples, a single (e.g., annular) optical film 240 may be disposed above multiple (including all) light detectors 204. In some examples, the edge of the optical film 240 may extend to (e.g., contact) the optical spacer 216.

[0039] Fresnel lens 242 may be a lens configured to direct and / or focus light emitted by a light emitter. Fresnel lens 242 may at least partially cover a portion of window 203 corresponding to light passing through the plurality of first light emitters 206 and / or second light emitters 208. That is, Fresnel lens 242 may be located within the field of view of the plurality of first light emitters 206 and the field of view of the plurality of second light emitters 208. Fresnel lens 242 may be configured for measurement of one or more target types. In some examples, Fresnel lens 242 may be configured for shielding of light emitters. For example, features of Fresnel lens 242 may be designed to achieve optimal measurements associated with second light emitters 208 and associated with the plurality of first light emitters 206 while also reducing the visibility of the light emitters.

[0040] In addition, the device 200 may include one or more layers for reducing the visibility of other components. The opaque mask 219 may be configured to reduce the visibility of the edges of the optical isolator 216 and / or the optical film 240 by being opaque at one or more wavelengths (e.g., the wavelengths measured by the device). In some examples, a portion of the opaque mask 219 may extend beyond the wall of the cavity (e.g., generated by the optical isolator 216). In some examples, the opaque mask 219 and the optical isolator 216 may include the same material and / or function (e.g., acting as an optical isolator and / or an aesthetic layer). At least one end of the opaque mask 219 and / or the optical isolator 216 may be positioned on or adjacent to the inner surface of the window 203 (i.e., the surface farthest from the outer surface of the housing of the device 200). The device 200 may also include an adhesive 215 that is configured to adhere one or more components (e.g., the optical film 240, the opaque mask 219, etc.) to the window 203.

[0041] Figure 2C A top view of a concentric structure including a selective transparent layer covering according to an example of the present disclosure is shown. Figure 2D1 shows an enlarged view of a selectively transparent layer covering a single light detector according to an example of the present disclosure. The selectively transparent layer 210 may be located in a peripheral area (e.g., Figure 2A The selectively transparent layer 210 can be configured to conceal the routing traces and contact pads 212 and / or the edges of the plurality of light detectors 204. Thus, the selectively transparent layer 210 can be positioned between the optical film 240 and the adhesive 215. The selectively transparent layer 210 can include one or more first sections 211A of material at least partially transparent to light in a second wavelength range (e.g., infrared wavelengths), wherein the transparency can be configured to allow light to reach the plurality of light detectors 204 for use, for example, in auxiliary measurements. The selectively transparent layer 210 can also include one or more second sections 211B covering a central portion of each light detector 204 to allow light in a first wavelength range (e.g., visible wavelengths) to reach the plurality of light detectors 204 for use, for example, in primary measurements. The one or more second sections 211B covering the central portion can include material transparent to the second wavelength range or can be omitted (e.g., an opening). In some cases, the one or more second sections 211B can also be transparent to the first wavelength range.

[0042] In some examples, the first portion 211A can be partially transparent (ie, partially blocking) to the first wavelength range and completely transparent to the second wavelength range.

[0043] The selectively transparent layer 210 can be located anywhere within the field of view of the plurality of light detectors 204. For example, the selectively transparent layer 210 can be located between the optical film 240 and the window 203. Examples of the present disclosure may include the selectively transparent layer 210 as a separate layer from the window 203. In other cases, the selectively transparent layer 210 can be formed within the window 203.

[0044] In some examples, a device may include one or more components configured to redirect light that may not include physiological information, thereby preventing unwanted light from reaching the light detector. Figure 2E A cross-sectional view of an exemplary electronic device including a concentric structure and a retroreflector according to an example of the present disclosure is shown. The device 200 may include a retroreflector 233 positioned adjacent to the optical spacer 216. In some cases, the retroreflector 233 may be implemented as a component of the optical sensing unit. The retroreflector 233 may replace Figure 2CThe opaque mask 219 shown in FIG. 2 may be positioned between the central region 209 (including the first light emitter 206 and the second light emitter 208) and the peripheral region 205 (including the light detector 204). The retroreflector 233 may be a ring or arc positioned around the central region 209. Alternatively, the retroreflector 233 may be positioned in one or more sections of the ring, while the opaque mask (e.g., the opaque mask 219) may be positioned in one or more other sections of the ring. In some examples, one or more sections of the ring may not include the retroreflector 233 or the opaque mask 219.

[0045] The retroreflector 233 may be a component that reflects light back in a direction parallel or nearly parallel to the light source, but in an opposite direction relative to its origin, regardless of the angle of incidence. For example, light from the light emitter 206 may be reflected from an interface (e.g., an outer surface, which may be a surface opposite the retroreflector 233) of the window 203. The light may reach the light detector 204 without interacting with the sample and, therefore, may not include physiological information. Instead of allowing the light to reach the light detector 204, the retroreflector 233 may reflect the light back toward the interface (e.g., in a direction away from the light detector 204).

[0046] In some examples, the retroreflector can include one or more features having properties (e.g., 20 degrees, 60 degrees, 90 degrees, etc.) configured to selectively reflect light within a range of incident angles. In some examples, the one or more features can reflect light back in a direction that is not parallel or not nearly parallel to the incident light. In some examples, the retroreflector 233 can be wavelength independent, where a wide range of wavelengths can be reflected back.

[0047] In some cases, the device 200 may include both the retroreflector 233 and the opaque mask 219, e.g. Figure 2F As shown. Retroreflector 233 can be positioned closer to light emitters 206 and 208 (and / or light detector 204C) than opaque mask 219. Opaque mask 219 can also help prevent unwanted light from reaching light detector 204 by including a material that absorbs light reflected from one or more interfaces of window 203. In some examples, such as Figure 2E-2F As shown, the retroreflector 233 and / or the opaque mask 219 can have a greater width (e.g., can extend) than the optical isolator 216, which can reduce crosstalk between the light emitters 206 and 208 and the light detector 204. In some examples, the opaque mask 219 can have a smaller width than the retroreflector 233. Additionally or alternatively, the retroreflector 233 and / or the opaque mask 219 can include one or more materials (e.g., black ink) that hide the underlying components (e.g., the optical isolator 216) from the user's eye.

[0048] In some examples, device 200 may include a lens having multiple regions. Figure 2G-2H A cross-sectional view and a top view are respectively shown of an exemplary electronic device including a lens having multiple regions according to an example of the present disclosure. Device 200 may include lens region 242A and lens region 242B (collectively referred to as lens 242). Different lens regions may have different optical and / or physical properties. For example, lens region 242A may be a Fresnel lens that covers second light emitter 208A (i.e., is located in its field of view). Lens region 242A may include multiple features (e.g., ridges) for focusing (e.g., collimating) light emitted by second light emitter 208A. Lens region 242B may cover at least two of the multiple first light emitters 206. Lens region 242B may include one or more other features (e.g., prisms) for controlling the light emitted by the multiple first light emitters 206.

[0049] In some cases, lens 242 can be a separate layer from window 203. In other examples, lens 242 can be formed as part of window 203 (ie, inseparable therefrom).

[0050] In the case where the second light emitter 208 emits second light having a second wavelength, such as infrared light, and the first light emitter 206 emits first light having a first wavelength, such as visible (e.g., green) light, the second light may have different characteristics than the first light. For example, the second light may have a lower signal strength (or signal-to-noise ratio (SNR)), and the lens region 242A (associated with the second light) may have one or more characteristics for enhancing the associated signal or SNR.

[0051] Exemplary Operation of Sensing Unit

[0052] The sensing unit may be operated using one or more merging techniques. Figure 3 An exemplary process for using a merging technique for one or more channels according to an example of the present disclosure is shown. One or more light detectors (e.g., all of the plurality of light detectors 204) can be associated with one or more channels (step 352 of process 350). In some examples, the channels can be dynamically changed based on the selected light emitters (step 353 of process 350). In some examples, the channels can be dynamically changed based on the spacing.

[0053] For a given channel, one or more light emitters (e.g., second light emitter 208A) may emit light (e.g., infrared light) (step 354 of process 350). A portion of the light may be absorbed by the user's skin, vessels, and / or blood, and a portion of the light may be returned to a light detector. The light detector associated with the given channel may measure the returned light and may generate one or more signals indicative of the measured returned light (step 356 of process 350). The signals in the channels may be read out and processed (e.g., summed) together, for example, to generate a channel signal (step 358 of process 350). This process may measure the channels sequentially or simultaneously. In scenarios where channels are measured sequentially, the process may be repeated for additional channels until some or all channels have been measured for a given light emitter. In some examples, multiple (including all) channels may be read out simultaneously, with signals within the same channel processed separately from signals from other channels. Another light emitter (e.g., first light emitter 206A) may be selected for measurement (steps 364 and 366 of process 350). Measuring multiple light emitters may allow the system to measure multiple areas of the user's skin to improve measurement accuracy.From the combined signals, physiological information may be determined (step 368 of process 350).

[0054] Examples of the present disclosure may include a single channel, with some (including all) of the photodetectors associated with the single channel. In the case of a single channel, all signals from all of the multiple photodetectors can be processed together. Single channel association can allow for higher total signal acquisition, which can improve the SNR of light emitter 408A. Examples of the present disclosure may also include each photodetector being associated with a unique channel. For example, a system may be configured with eight photodetectors and eight channels. In this way, the signal from each photodetector can be processed separately.

[0055] Additionally or alternatively, the system may be configured with other associations. Figures 4A-4E An exemplary association of light detectors with channels according to examples of the present disclosure is shown. Figure 4ATwo channels are shown, where photodetectors located on one side of the device (e.g., photodetector 404A, photodetector 404B, photodetector 404C, and photodetector 404D) may be associated with a first channel 420, while photodetectors located on the other side of the device (e.g., photodetector 404E, photodetector 404F, photodetector 404G, and photodetector 404H) may be associated with a second channel 421. The unique relationship between each photoemitter and the channel can result in different information. Generally, signal information may include higher signal strength for shorter separation distances between photoemitters and photodetectors. When a photoemitter is emitting light (i.e., activated), the signal information measured by each channel may be the same. For example, when photoemitter 406A is emitting light, light is detected by all photodetectors associated with a given channel. Channel 420 and channel 421 may include high signal information from photodetector 404A and photodetector 404H, respectively, and low signal information from photodetector 404D and photodetector 404E, respectively. When another light emitter is emitting light, the signal information measured by each channel can be different. For example, when light emitter 406B is emitting light, channel 420 may include high signal information from light detectors 404B and 404C, and medium signal information from light detectors 404A and 404D. Channel 421 may include low signal information from light detectors 404E, 404H, 404F, and 404G. In this way, the same light detector can measure different sets of signals depending on which light emitter is activated.

[0056] While the figure illustrates one channel as including a light detector on the right and another channel as including a light detector on the left, examples of the present disclosure may include the same number of channels (e.g., two), but the associations may include different light detectors. For example, channel 420 may include light detectors 404C, 404D, 404E, and 404F, while channel 421 may include light detectors 404G, 404H, 404A, and 404B (not shown). In some examples, channel associations may be based on the relative positions of light emitters.

[0057] Figure 4BFour channels are shown according to an example of the present disclosure. Each channel may include two adjacent light detectors, where the emitters have the same separation distance relative to the center of the light detectors. For example, channel 422 may include light detector 404A and light detector 404H; channel 423 may include light detector 404B and light detector 404C; channel 424 may include light detector 404D and light detector 404E; and channel 425 may include light detector 404F and light detector 404G. The unique relationship between each light emitter relative to the channel may result in different information. For example, when light emitter 406A is activated, the signal from channel 422 may include different information than channel 424. With a greater number of channels (e.g., relative to Figure 4A In the case of two channels being correlated as shown, the localization of the measurement area on the user's skin can be enhanced, thereby improving the SNR of the measurement. The localization of the measurement area can refer to the amount of information in the signal from the area adjacent to a given light detector.

[0058] Figure 4C Two channels are shown, wherein the channels can be unevenly distributed. In some cases, the number of light detectors associated with each channel can be different. For example, channel 426 may include six light detectors (e.g., light detector 404C, light detector 404D, light detector 404E, light detector 404F, light detector 404G, and light detector 404H), while channel 427 may include two light detectors (e.g., light detector 404A and light detector 404B). The system can be configured so that the signal from one channel can be used for one type of information, while the signal from another channel can be used for another type of information. For example, channel 427 may have an improved localization of the target measurement area on the user's skin and can be used to determine the user's physiological information. In the case of reduced localization, channel 426 can be used for wrist removal detection and / or ambient light sensing. The signal from channel 426 can, for example, be interrupted or used to adjust the measurement associated with channel 427. As another example, channel 426 may have a larger sampling area than channel 427. A light detector may be associated with a certain channel based on signal quality.

[0059] Figure 4DMultiple channels are shown according to examples of the present disclosure, wherein at least one channel includes non-adjacent photodetectors. Channel 428 may include a first group of adjacent photodetectors 404A and 404H and a second group of adjacent photodetectors 404D and 404E, wherein the first group may be spatially separated (i.e., non-adjacent) relative to the second group along a concentric arrangement by at least one other photodetector (i.e., not included in the same channel). Channel 429 may include a first group of adjacent photodetectors 404B and 404C and a second group of adjacent photodetectors 404F and 404G, wherein the first group may be spatially separated relative to the second group by at least one other photodetector. That is, one or more of the first and second channels may include two groups of adjacent photodetectors (e.g., a first group may include photodetector 404A and photodetector 404H), wherein the two groups may not be adjacent (e.g., a second group may include photodetector 404D and photodetector 404E, wherein the second group may not be adjacent to the first group). The first channel and the second channel may have one or more different light detectors (eg, light detector 404G may not be included in both the first channel and the second channel).

[0060] In this channel association, one set of photodetectors can measure pulsation information, while another set of photodetectors can measure non-pulsation (e.g., dark) information. For example, when photoemitter 406A is activated, pulsation information for channel 428 may be generated by photodetectors 404A and 404H, but may not be generated by photodetectors 404D and 404E. Which photodetector(s) measure pulsation information for a given channel may depend on the activated photoemitter. For example, when another photoemitter (e.g., photoemitter 406B) is activated, pulsation information for channel 428 may not be measured by photodetectors 404A and 404H; the other photoemitter may be a photoemitter not adjacent to the corresponding photodetectors. Conversely, photodetectors 404D and 404E may generate pulsation information when photoemitter 406B is activated.

[0061] In this way, the same channel can be effectively used to measure different locations. For example, light emitter 406A and light emitter 406D can be assigned to the same channel 428. The signal measured by the first one or more light detectors 404 in the channel can measure useful information when one light emitter is active, while the second one or more light detectors 404 in the same channel cannot. Subsequently, the detector that measures useful information (e.g., to be included in the determination of physiological information) can be different when another light emitter is active.

[0062] Figure 4E Three channels are shown, each of which may include a different level of signal information. A first association may include two sets of adjacent photodetectors that are not adjacent (e.g., Figure 4D), and the second association may include one or more photodetectors adjacent to at least one photodetector in the first association (e.g., photodetector 404G may be adjacent to photodetector 404H). For example, channel 430 may include photodetector 404A, photodetector 404H, photodetector 404D, and photodetector 404E. Channel 431 may include photodetector 404B and photodetector 404G; and channel 432 may include photodetector 404C and photodetector 404F. When light emitter 406A is activated, channel 430 may include the highest level of heartbeat signal information, channel 431 may include a medium level, and channel 432 may include the lowest level. When light emitter 406B or light emitter 406D is activated, channels 431 and 432 may include the highest level of heartbeat signal information, and channel 430 may include the lowest level. When light emitter 406C is activated, channel 430 may include the highest level of heartbeat information, channel 432 may include a medium level, and channel 431 may include the lowest level.

[0063] In some examples, the merging and channel associations can be changed dynamically without user interaction. The channel associations can be based on the operating mode. For example, when the system is in a first measurement operating mode, the system can be configured to have a single channel including all eight light detectors. When the system switches to a second measurement operating mode, the system can dynamically switch to multiple (e.g., two, three, four, etc.) channels (e.g., Figures 4A-4E shown).

[0064] In some examples, the system can switch to a specific channel association based on the measured signal information. For example, if the system is configured with two channels, such as Figure 4A As shown and channel 420 produces a higher pulsation signal information after a certain number of measurements compared to channel 421, the system can switch to Figure 4C . If, after the channel association is switched, higher pulsating signal information is associated with channel 427, the system can determine that one or more areas on the user's skin (e.g., localized proximate to channel 427) may be optimal for the given user. In this way, the system can adjust for the user, the user's condition (e.g., one or more materials such as the user's sleeve unintentionally blocking the optical components), and / or the environmental conditions (e.g., a higher level of ambient light incident on one or more light detectors).

[0065] The above-described channel association can be implemented in post-processing, where one or more (including all) photodetectors can be hardwired together. Examples of the present disclosure can also include one or more switches for dynamically switching which photodetectors are electrically coupled (e.g., hardwired) together. Additionally or alternatively, one or more photodetectors and / or channels can be deactivated. For example, if the system determines that channel 427 ( Figure 4C ) includes the highest level of pulsation information, the system can deactivate light detectors (e.g., light detector 404C, light detector 404D, light detector 404E, light detector 404F, light detector 404G, and light detector 404H) included in another channel, such as channel 426, to save power.

[0066] Figure 5 An exemplary block diagram of a computing system including a concentric structure for optical sensing according to an example of the present disclosure is shown. The computing system 500 may correspond to Figure 1A-1C Computing system 500 may include a processor 510 configured to execute instructions and perform operations associated with computing system 500. For example, using instructions retrieved from a memory, processor 510 may control the receipt and manipulation of input and output data between components of computing system 500. Processor 510 may be a single-chip processor or may be implemented by multiple components.

[0067] In some examples, processor 510, along with an operating system, is operable to execute computer code and generate and use data. The computer code and data may reside in a program storage block 502 operatively coupled to processor 510. Program storage block 502 generally provides a location for storing data used by computing system 500. Program storage block 502 may be any non-transitory computer-readable storage medium (excluding signals) and may store, for example, historical and / or pattern data related to PPG signals and perfusion index values measured by one or more photodetectors, such as photodetector 504. By way of example, program storage block 502 may include read-only memory (ROM) 518, random access memory (RAM) 522, a hard drive 508, and the like. The computer code and data may also reside on removable storage media and be loaded or installed onto computing system 500 when needed. Removable storage media include, for example, CD-ROMs, DVD-ROMs, universal serial buses (USBs), secure digital (SD), compact flash (CF), memory sticks, multimedia cards (MMCs), and network components.

[0068] Computing system 500 may also include an input / output (I / O) controller 512 operably coupled to processor 510, or the I / O controller may be a separate component, as shown. I / O controller 512 may be configured to control the interaction with one or more I / O devices. I / O controller 512 may operate by exchanging data between processor 510 and the I / O device that wishes to communicate with processor 510. I / O devices and I / O controller 512 may communicate via a data link. The data link may be a unidirectional link or a bidirectional link. In some cases, the I / O device may be connected to I / O controller 512 via a wireless connection. By way of example, the data link may correspond to PS / 2, USB, FireWire, IR, RF, Bluetooth, etc.

[0069] The computing system 500 may include a display device 524 operatively coupled to the processor 510. The display device 524 may be a separate component (peripheral device) or may be integrated with the processor 510 and the program storage block 502 to form a desktop computer (e.g., an all-in-one computer), a laptop computer, a handheld or tablet computing device, etc. The display device 524 may be configured to display a graphical user interface (GUI) to a user, which may include a pointer or cursor and other information. By way of example, the display device 524 may be any type of display, including a liquid crystal display (LCD), an electroluminescent display (ELD), a field emission display (FED), a light emitting diode display (LED), an organic light emitting diode display (OLED), etc.

[0070] The display device 524 can be coupled to a display controller 526, which can be coupled to the processor 510. The processor 510 can send raw data to the display controller 526, and the display controller 526 can send signals to the display device 524. The data can include voltage levels for a plurality of pixels in the display device 524 to project an image. In some examples, the processor 510 can be configured to process the raw data.

[0071] The computing system 500 may also include a touch screen 530 operably coupled to the processor 510. The touch screen 530 may be a combination of a sensing device 532 and a display device 524, wherein the sensing device 532 may be a transparent panel positioned in front of or integrated with the display device 524. In some cases, the touch screen 530 may identify touches and the location and magnitude of the touches on its surface. The touch screen 530 may report the touches to the processor 510, and the processor 510 may interpret the touches according to its programming. For example, the processor 510 may perform tap and event gesture parsing and may initiate device wakeup or power on one or more components based on a particular touch.

[0072] Touch screen 530 may be coupled to touch controller 540, which may acquire data from touch screen 530 and provide the acquired data to processor 510. In some cases, touch controller 540 may be configured to send raw data to processor 510, and processor 510 may process the raw data. For example, processor 510 may receive data from touch controller 540 and determine how to interpret the data. The data may include the coordinates of the touch and the applied pressure. In some examples, touch controller 540 may be configured to process the raw data itself. That is, touch controller 540 may read signals from sensing points 534 located on sensing device 532 and convert these signals into data that processor 510 can understand.

[0073] Touch controller 540 may include one or more microcontrollers, such as microcontroller 542, each of which may monitor one or more sensing points 534. Microcontroller 542 may correspond to, for example, an application specific integrated circuit (ASIC) that cooperates with firmware to monitor signals from sensing device 532, process the monitored signals, and report this information to processor 510.

[0074] One or both of the display controller 526 and the touch controller 540 may perform a filtering process and / or a conversion process. The filtering process may be implemented to reduce the busy data flow to prevent the processor 510 from being overloaded with redundant or unnecessary data. The conversion process may be implemented to adjust the raw data before sending or reporting to the processor 510.

[0075] In some examples, sensing device 532 may be based on capacitance. When two conductive members are in close proximity without actually touching, the electric fields of the two conductive members may interact to form a capacitance. The first conductive member may be one or more of sensing points 534, and the second conductive member may be an object 590, such as a finger. When object 590 approaches the surface of touch screen 530, capacitance may form between object 590 and one or more sensing points 534 proximate to object 590. By detecting changes in capacitance at each of sensing points 534 and recording the positions of sensing points 534, touch controller 540 can identify multiple objects and determine the position, pressure, direction, velocity, and acceleration of object 590 as it moves across touch screen 530. For example, touch controller 540 can determine whether the sensed touch is a finger, a tap, or an object covering the surface.

[0076] Sensing device 532 may be based on self-capacitance or mutual capacitance. In self-capacitance, each of sensing points 534 may be provided by a separately charged electrode. When object 590 approaches the surface of touch screen 530, the object may capacitively couple to the electrodes immediately adjacent to object 590, thereby stealing charge from the electrodes. The amount of charge in each of these electrodes may be measured by touch controller 540 to determine the location of one or more objects when they touch or hover over touch screen 530. In mutual capacitance, sensing device 532 may include a two-layer grid (not shown) of spatially separated wires or conductors, but other configurations are possible. The upper layer may include wires in rows, while the lower layer may include wires in columns (e.g., orthogonal). Sensing points 534 may be provided at the intersections of the rows and columns. During operation, charging may be performed by row, and charge may be capacitively coupled from the rows to the columns. When object 590 approaches the surface of touch screen 530, object 590 may capacitively couple to the rows immediately adjacent to object 590, thereby reducing charge coupling between the rows and columns. The amount of charge in each column can be measured by touch controller 540 to determine the positions of multiple objects when touching touch screen 530 .

[0077] The computing system 500 may also include one or more light emitters, such as light emitter 506, and one or more light detectors, such as light detector 504, positioned near the user's skin 520. Light emitter 506 may be configured to generate light, and light detector 504 may be configured to measure light back. Light detector 504 may send the measured raw data to processor 510, and processor 510 may perform noise and / or artifact removal to determine a PPG signal and / or perfusion index. Processor 510 may dynamically activate light emitters and / or light detectors based on the application, user skin type, and usage conditions. In some examples, for example, some light emitters and / or light detectors may be activated while others may be deactivated to conserve power. In some examples, processor 510 may store the raw data and / or processed information in ROM 518 or RAM 522 for historical tracking or for future diagnostic purposes.

[0078] In some examples, the light detector can measure the light information, and the processor can determine the PPG signal and / or perfusion index from the returned light. Processing of the light information can also be performed on the device. In some examples, processing of the light information need not be performed on the device itself. Figure 6 6 shows an exemplary configuration in which an electronic device according to an example of the present disclosure is connected to a host. The host 610 may be any device external to the device 600, including but not limited to a server or a Figure 1A-1CAny of the systems shown. Device 600 can be connected to host 610 via communication link 620. Communication link 620 can be any connection, including but not limited to wireless connections and wired connections. Exemplary wireless connections include Wi-Fi, Bluetooth, Wireless Direct, and infrared. Exemplary wired connections include Universal Serial Bus (USB), FireWire, Thunderbolt, or any connection that requires a physical cable.

[0079] In operation, rather than processing the light information from the light detectors on system 600 itself, system 600 may instead send raw data 630 measured from the light detectors to host 610 via communication link 620. Host 610 may receive raw data 630 and process the light information. Processing the light information may include removing or reducing any noise due to artifacts and determining physiological signals such as the user's heart rate. Host 610 may include algorithms or calibration procedures to account for differences in user characteristics that affect PPG signals and perfusion index. Additionally, host 610 may include storage or memory for tracking PPG signal and perfusion index history for diagnostic purposes. Host 610 may send processed results 640 or related information back to device 600. Based on processed results 640, device 600 may notify the user or adjust its operation accordingly. By offloading the processing and / or storage of light information, device 600 may save space and power—this allows device 600 to remain compact and portable, freeing up space on the device that would otherwise be required for processing logic.

[0080] As described above, aspects of the present technology include the collection and use of physiological information. This technology can be implemented in conjunction with technology that involves collecting personal data related to the user's health and / or that uniquely identifies or can be used to contact or locate a specific person. Such personal data may include demographic data, date of birth, location-based data, phone number, email address, home address, and data or records related to the user's health or fitness level (e.g., vital sign measurements, medication information, exercise information, etc.).

[0081] The present disclosure recognizes that a user's personal data (including physiological information, such as data generated and used by the present technology) can be used to benefit the user. For example, a user's heart rate can allow the user to track or otherwise gain insights into their health or fitness level.

[0082] This disclosure contemplates that entities responsible for collecting, analyzing, disclosing, transmitting, storing, or otherwise using such personal data will adhere to established privacy policies and / or practices. Specifically, such entities should implement and adhere to privacy policies and practices that are recognized as meeting or exceeding industry or government requirements for maintaining the privacy and security of personal data. Such policies should be easily accessible to users and updated as data collection and / or use changes. Personal information collected from users should be used for the entity's legitimate and reasonable purposes and not shared or sold beyond those legitimate uses. Furthermore, such collection / sharing should require the user's informed consent. Furthermore, such entities should consider taking any necessary steps to safeguard and secure access to such personal data and ensure that others with access to the personal data comply with their privacy policies and procedures. Furthermore, such entities may subject themselves to third-party assessments to demonstrate compliance with widely accepted privacy policies and practices. These policies and practices may be tailored to the geographic region and / or the specific type and nature of the personal data collected and used.

[0083] Regardless of the foregoing, the present disclosure also contemplates embodiments in which users can selectively block the collection, use, or access of personal data, including physiological information. For example, users may be able to disable hardware and / or software components that collect physiological information. Furthermore, the present disclosure contemplates providing hardware and / or software components that prevent or block access to collected personal data. Specifically, users may choose to remove, disable, or limit access to certain health-related applications that collect the user's personal health or fitness data.

[0084] A device is disclosed herein. In some examples, the device includes: an optical sensing unit, the optical sensing unit including: a central area, the central area including: a plurality of first light emitters configured to emit a first light path having a first wavelength; one or more second light emitters configured to emit a second light path having a second wavelength different from the first wavelength, wherein the plurality of first light emitters are positioned closer to a peripheral area than the one or more second light emitters; and the peripheral area located around the central area, the peripheral area including: a plurality of light detectors configured to detect the first light path and the second light path, wherein the plurality of light detectors are oriented to be concentrically arranged. Additionally or alternatively, the device includes: a lens including a plurality of areas, the plurality of areas including: a first area covering the plurality of first light emitters; and a second area covering the one or more second light emitters, wherein the optical properties of the first area are different from the optical properties of the second area. Additionally or alternatively, in some examples, the center of each light detector is positioned a first spacing distance from at least one of the one or more second light emitters. Additionally or alternatively, in some examples, each light detector is positioned at a first spacing distance from one of the one or more second light emitters and at a second spacing distance from one of the plurality of first light emitters, wherein the first spacing distance is greater than the second spacing distance. Additionally or alternatively, in some examples, another light detector is positioned at a third spacing distance from the one of the plurality of first light emitters, wherein the third spacing distance is greater than the first spacing distance, the second spacing distance, or both. Additionally or alternatively, in some examples, each of the plurality of first light emitters is positioned at a radial angle relative to a center of the central region, and edges of two of the plurality of light detectors are positioned at the radial angle relative to the center of the central region. Additionally or alternatively, in some examples, each of the first light emitters is positioned such that a spacing distance between the corresponding first light emitter and one of the plurality of light detectors is the same as a spacing distance between the corresponding first light emitter and another of the plurality of light detectors, wherein the one of the plurality of light detectors and another of the plurality of light detectors are adjacent light detectors. Additionally or alternatively, in some examples, the device further comprises: an optical spacer positioned between the plurality of first and second light emitters and the plurality of light detectors. Additionally or alternatively, the optical spacer is annular. Additionally or alternatively, in some examples, a wall of the optical spacer defines one or more cavities, wherein the plurality of first light emitters and the one or more second light emitters are positioned in the cavity separate from the plurality of light detectors.Additionally or alternatively, in some examples, the device further comprises: a retroreflector positioned between the central region and the peripheral region, wherein the retroreflector is configured to reflect light in a direction away from at least one of the plurality of detectors. Additionally or alternatively, in some examples, the device further comprises: one or more windows positioned adjacent to the central region and the peripheral region; and an opaque mask positioned between the central region and the peripheral region, wherein the opaque mask is configured to absorb light reflected from an interface of the one or more windows. Additionally or alternatively, in some examples, the device further comprises: a selectively transparent layer positioned in the peripheral region, the selectively transparent layer comprising a plurality of first sections and a plurality of second sections, wherein the plurality of first sections cover one or more first portions of the peripheral region, and the plurality of second sections cover one or more second portions of the peripheral region, the one or more second sections covering the plurality of light detectors. Additionally or alternatively, in some examples, the plurality of first sections comprise a material that is partially transparent to the first wavelength and transparent to the second wavelength. Additionally or alternatively, in some examples, the plurality of second sections comprise no material. Additionally or alternatively, in some examples, the selectively transparent layer is annular. Additionally or alternatively, in some examples, the device further comprises: a Fresnel lens located in the central region covering the plurality of first light emitters and the one or more second light emitters; and one or more optical film segments located in the peripheral region covering the plurality of light detectors, wherein the one or more optical film segments are configured to limit light from passing through the peripheral region. Additionally or alternatively, in some examples, the first wavelength comprises one or more visible wavelengths, and the second wavelength comprises one or more infrared wavelengths. Additionally or alternatively, in some examples, the first region of the lens is a Fresnel lens, and the second region of the lens comprises a plurality of prisms.

[0085] A method of operating a device is disclosed. The method includes associating a plurality of light detectors to a plurality of channels during a first time; for each light emitter: emitting light from a corresponding light emitter; sequentially measuring at least a portion of the emitted light through the one or more channels; and selecting and changing to another association such that at least one of the plurality of light detectors is associated with another channel during a second time, the selected another association being based on one or more of the measurements. Additionally or alternatively, in some examples, the association during the first time or the second time includes each channel having adjacent light detectors. Additionally or alternatively, in some examples, the association during the first time or the second time includes each channel having one or more of the plurality of light detectors in a first group and one or more of the plurality of light detectors in a second group, the first group being spatially separated from the second group. Additionally or alternatively, in some examples, the method further includes determining physiological information using measurements from the first group when one light emitter is emitting, and determining physiological information using measurements from the second group when another light emitter is emitting. Additionally or alternatively, in some examples, one association includes a single channel including all of the plurality of light detectors, while another association includes multiple channels. Additionally or alternatively, in some examples, the signal from the one association is used for primary measurement information, while the signal from the other association is used for auxiliary measurement information. Additionally or alternatively, in some examples, the association during the first time period includes two groups of adjacent light detectors, the two groups being non-adjacent. Additionally or alternatively, in some examples, the association during the second time period includes one or more light detectors that were adjacent to at least one light detector in the association during the first time period.

[0086] Although the disclosed examples have been fully described with reference to the accompanying drawings, it should be noted that various changes and modifications will become apparent to those skilled in the art. It should be understood that such changes and modifications are considered to be included within the scope of the disclosed examples as defined by the appended claims.

Claims

1. A wearable electronic device comprising: Equipment housing; a strap attached to the device housing and configured to hold the device housing on a user's wrist; a processor located within the device housing; as well as an optical sensing unit, located at least partially within the device housing, and comprising: central area; a peripheral area surrounding the central area; a first light emitter located in the central region and configured to emit first light within a first wavelength range; a second light emitter located in the central region and configured to emit second light within a second wavelength range different from the first wavelength range; a photodetector group located in the peripheral region and configured to detect the first light and the second light, the photodetector group at least partially surrounding the first light emitter and the second light emitter in a concentric manner; and a selectively transparent layer located in the peripheral region and comprising: a first portion covering a central portion of a photodetector in the photodetector group and being transparent to the second wavelength range to allow light of the second wavelength range to reach the photodetector; and A second portion surrounds the first portion, the second portion being at least partially transparent to the first wavelength range and opaque to the second wavelength range.

2. The wearable electronic device according to claim 1, wherein: said first portion of said selectively transparent layer being a first portion of a group of first portions; each first portion of the set of first portions is located over a corresponding photodetector of the set of photodetectors; as well as The second portion surrounds each first portion in the group of first portions.

3. The wearable electronic device according to claim 1, wherein: The first wavelength range includes infrared wavelengths; and The second wavelength range includes visible light wavelengths.

4. The wearable electronic device according to claim 1, wherein: The first portion is at least partially transparent to the first wavelength range; and The second portion is completely transparent to the first wavelength range. The wearable electronic device according to claim 1 , wherein the first portion is an opening portion of the selectively transparent layer.

6. The wearable electronic device according to claim 1, wherein: The wearable electronic device further includes: a window located above the central area and the peripheral area of the optical sensing unit, the window defining a portion of an outer surface of the wearable electronic device; and The selectively transparent layer is positioned along an inner surface of the window opposite the outer surface.

7. The wearable electronic device according to claim 1, wherein: The optical sensing unit further includes: a first wall extending around the central region between the central region and the peripheral region; and a second wall extending around the peripheral region; The first light emitter and the second light emitter are positioned in a first cavity, the first cavity being defined at least in part by the first wall; and The light detector array is positioned in a second cavity defined at least in part by the first wall and the second wall, and the second cavity extends around the first cavity.

8. The wearable electronic device according to claim 7, wherein: The optical sensing unit further includes an optical isolator configured to at least partially surround the first light emitter, the second light emitter, and the light detector group; and The first wall, the second wall, the first cavity and the second cavity together form the optical isolation member.

9. The wearable electronic device according to claim 7, wherein: The wearable electronic device further includes: a window located above the central area and the peripheral area of the optical sensing unit, the window defining a portion of an outer surface of the wearable electronic device; and The optical sensing unit further includes: a lens, located between the first cavity and the window; an optical film, located between the second cavity and the window; a first opaque mask positioned between the first wall and the window and extending around the central region; and A second opaque mask is located between the second wall and the window.

10. A wearable electronic device comprising: an equipment housing defining an opening; a processor located within the device housing; a window located above the opening and defining a portion of an exterior surface of the wearable electronic device; An optical sensing unit is located below the window and includes: central area; a first light emitter located in the central region and configured to emit first light within a first wavelength range; a second light emitter group disposed around the first light emitter and configured to emit a second light within a second wavelength range different from the first wavelength range; a light detector group concentrically disposed around the second light emitter group and configured to detect the first light and the second light; and a selectively transparent layer located between the photodetector array and the window and comprising: a group of first portions, each first portion of the group of first portions covering a central portion of a corresponding photodetector of the group of photodetectors and being transparent to the second wavelength range to allow light of the second wavelength range to reach the group of photodetectors; and A second portion surrounds each first portion of the group of first portions, the second portion being at least partially transparent to the first wavelength range and opaque to the second wavelength range.

11. The wearable electronic device according to claim 10, wherein the optical sensing unit further comprises: A wall is located between the second light emitter group and the light detector group and extends around the first light emitter group and the second light emitter group.

12. The wearable electronic device according to claim 11, wherein: The optical sensing unit further includes: a lens located between the window and the first light emitter and the second light emitter group; and The wall extends around the lens.

13. The wearable electronic device according to claim 11, wherein the optical sensing unit further comprises: An opaque mask is positioned between the wall and the window.

14. The wearable electronic device according to claim 13, wherein: The wall is a first wall; The opaque mask is a first opaque mask; as well as The optical sensing unit also includes: a second wall extending around the photodetector array; as well as A second opaque mask is located between the second wall and the window.

15. The wearable electronic device according to claim 11, wherein: The wall is a first wall; as well as The optical sensing unit further includes: a second wall extending around the photodetector array; as well as An optical film is located between the light detector group and the window, and between the first wall and the second wall.

16. The wearable electronic device according to claim 9, wherein: The first wavelength range includes infrared wavelengths; and The second wavelength range includes visible light wavelengths.

17. An optical sensing unit for a wearable electronic device, comprising: An optical isolator, the optical isolator comprising: a first wall extending around the first cavity and at least partially defining the first cavity; a second wall extending around the first wall and at least partially defining a second cavity between the first and second walls; a first light emitter, located in the first cavity and configured to emit first light within a first wavelength range; a second light emitter located in the first cavity and configured to emit second light within a second wavelength range different from the first wavelength range; a light detector group, arranged concentrically around the first light emitter and the second light emitter in the second cavity of the optical sensing unit and configured to detect the first light and the second light; and Selective transparency layer, comprising: a first portion covering a central portion of a photodetector in the photodetector group and being transparent to the second wavelength range to allow light of the second wavelength range to reach the photodetector group, and A second portion surrounds the first portion, the second portion being at least partially transparent to the first wavelength range and opaque to the second wavelength range.

18. The optical sensing unit according to claim 17, further comprising: a Fresnel lens, located above the first light emitter; as well as A prism is located above the second light emitter.

19. The optical sensing unit according to claim 17, wherein: The second light emitter is a light emitter in a second light emitter group; and The second light emitter group is disposed to surround the first light emitter.

20. The optical sensing unit according to claim 19, wherein: The optical sensing unit further includes: a first lens region, located above the first light emitter and comprising a Fresnel lens; and The second lens region is located above the second light emitter group and includes a prism group, each prism in the prism group is located above a corresponding second light emitter of the second light emitter group.

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