Electronic devices having optical sensing modules

Abstract

Described herein are optical sensing modules, as well as electronic devices incorporating the optical sensing modules, that are configured to perform one or more optical measurements. The optical sensing module is configured to house a light emitter array and a light detector array. Specifically, the optical sensing module may include a cover assembly that defines a plurality of windows, including at least a detection window positioned over the light detector array and one or more emission windows positioned over the light emitter array. Overall, the optical sensing modules described herein may provide for a range of optical sensing capabilities while maintaining a relatively compact form factor.

Description

ELECTRONIC DEVICES HAVING OPTICAL SENSING MODULESCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This PCT (Patent Cooperation Treaty) application claims priority to U.S. Provisional Patent Application No. 63 / 714,789, filed October 31 , 2024, the disclosure of which is hereby incorporated herein by reference in its entirety.FIELD

[0002] The described embodiments relate generally to optical sensing modules for electronic devices and electronic devices including the optical sensing modules. More particularly, the present embodiments relate to optical sensing modules that include an annular detection window surrounding a set of emission windows.BACKGROUND

[0003] Some electronic devices include optical sensing modules that are configured to perform one or more types of optical measurements. Specifically, the optical sensing module may, using one or more light emitters, emit light from the optical sensing module and may measure, using one or more light detectors, light that enters the optical sensing module. Information about the light that is emitted and measured during an optical measurement may be used to determine information about the environment surrounding the optical sensing module. For example, an optical measurement may be performed to determine a distance between the optical sensing module and an object, and in some instances may further identify a type of the object (e.g., to differentiate between human skin and other types of materials). Optical measurements may also be performed to measure one or more physiological parameters of a user, such as heart rate, blood oxygen saturation, or the like.

[0004] Different types of optical measurements, however, may be associated with different design constraints in order to balance accuracy and power efficiency. For example, different types of optical measurements may utilize different wavelengths and different signal processing algorithms, and may have different sensitivities to environmental interferences (e.g., ambient light and / or motion artifacts). Accordingly, it may be difficult to configure an optical sensing module to perform multiple types of optical measurements while maintaining power efficiency and a compact form factor.SUMMARY

[0005] Some embodiments are directed to an optical sensing module, or an electronic device incorporating the optical sensing module, that is configured to perform one or more optical measurements. The optical sensing module is configured to house a light emitter array and a light detector array. Specifically, the optical sensing module may include a cover assembly that defines a plurality of windows, including at least a detection window positioned over the light detector array and one or more emission windows positioned over the light emitter array. Overall, the optical sensing modules described herein may provide for a range of optical sensing capabilities while maintaining a relatively compact form factor.

[0006] The disclosure provides an electronic watch comprising a display assembly including a touch-sensitive layer, a front cover positioned over the display assembly, a housing coupled to the front cover, and an optical sensing module at least partially defining a rear surface of the electronic watch, the optical sensing module comprising a light emitter configured to emit light from the optical sensing module, a plurality of light detectors configured to detect light that enters the optical sensing module, a co-molded cover member coupled to the housing and comprising a first portion that partly defines an emission window positioned over the light emitter, the first portion formed from a first transparent zirconia material and defining a first tapered cross-section, a second portion that partly defines a detection window positioned over the plurality of light detectors, the second portion formed from a second transparent zirconia material and defining a second tapered cross-section, the second portion defining an annular shape, and a barrier portion positioned between and bonded to each of the first portion and the second portion and formed from a zirconia material that is opaque with respect to the light emitted from and entering the optical sensing module, the barrier portion bonded to each of the first and the second portions.

[0007] The disclosure also provides an electronic device comprising a display assembly, a light emitter array, a light detector array, and an enclosure surrounding the display assembly, the light emitter array, and the light detector array, the enclosure including a ceramic cover member defining at least a portion of a rearsurface of the electronic device, the ceramic cover member comprising a first barrier portion formed from a first zirconia material, a first window portion positioned over at least one light emitter of the light emitter array and formed from a second zirconia material, the first barrier portion surrounding and integrally formed with the first window portion, a second window portion positioned over the light detector array, surrounding and integrally formed with the first barrier portion, and formed from a third zirconia material, and a second barrier portion surrounding and integrally formed with the second window portion, the second barrier portion formed from a fourth zirconia material.

[0008] The disclosure also provides a wearable device, comprising a housing, a front cover coupled to the housing, a display assembly positioned below the front cover and at least partially surrounded by the housing, an optical sensing module comprising a plurality of light emitters, a plurality of light detectors, and a rear cover member comprising an inner opaque portion formed from a first zirconia material and defining a first annular shape, an inner transparent portion formed from a second zirconia material and positioned over the plurality of light emitters, the inner transparent portion bonded to an inner face of the inner opaque portion, an outer transparent portion formed from a third zirconia material, positioned over the plurality of light detectors, and defining a second annular shape, an inner face of the outer transparent portion bonded to an outer face of the inner opaque portion, and an outer opaque portion formed from a fourth zirconia material and bonded to an outer face of the outer transparent portion.

[0009] The disclosure also provides an electronic device comprising an optical sensing module defining an inner cavity and an outer cavity surrounding the inner cavity, the optical sensing module comprising a cover assembly defining a set of emission windows and an annular detection window surrounding the set of emission windows, a light emitter array positioned in the inner cavity and behind the set of emission windows, and a plurality of light detectors positioned in the outer cavity and behind the annular detection window, wherein each light detector of the plurality of light detectors has a trapezoidal shape.

[0010] The disclosure also provides an electronic device comprising an optical sensing module defining an inner cavity and an outer cavity surrounding the inner cavity, the optical sensing module comprising a cover assembly defining a plurality ofemission windows and an annular detection window surrounding the plurality of emission windows, a light detector array positioned in the outer cavity and behind the annular detection window, and a plurality of light emitters positioned in the inner cavity, the plurality of light emitters comprising a plurality of first light emitters configured to emit a first wavelength of light, a plurality of second light emitters configured to emit a second wavelength of light, and a plurality of third light emitters configured to emit a third wavelength of light, wherein the plurality of emission windows comprises a first subset of emission windows and a second subset of emission windows, each emission window of the first subset of emission windows is positioned over a corresponding first light emitter of the plurality of first light emitters, each emission window of the second subset of emission windows is positioned over a corresponding second light emitter of the plurality of second light emitters, and each emission window of the third subset of emission windows is positioned over a corresponding third light emitter of the plurality of third light emitters.

[0011] The disclosure also provides an electronic device comprising an optical sensing module defining an inner cavity and an outer cavity surrounding the inner cavity, the optical sensing module comprising a cover assembly defining a plurality of emission windows and a detection window, a light detector array positioned in the outer cavity, and a light emitter array positioned in the inner cavity, wherein the cover assembly comprises a cover member, an aperture layer attached to an interior surface of the cover member and defining a plurality of apertures, each aperture of the plurality of apertures at least partially defining a corresponding emission window of the plurality of emission windows, and a plurality of emission optical elements, each positioned at least partially within a respective aperture of the plurality of apertures, wherein each emission optical element of the plurality of emission optical elements comprises a corresponding micro-optic array.BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The disclosure will be readily understood by the following detailed description in combination with the accompanying drawings, where like reference numerals designate like elements.

[0013] FIGS. 1 and 1 B show front and rear views, respectively, of an example electronic device that includes an optical sensing module such as described herein. FIG. 10 shows an exploded perspective view of the electronic device of FIGS. 1 A and 1 B.

[0014] FIGS. 2A and 2B show top and cross-sectional side views, respectively, of a variation of a cover member that may be used with the optical sensing modules described herein. FIG. 2C is an enlarged view of a portion of the cover member shown in FIG. 2B. FIGS. 2D and 2E show top and cross-sectional side views, respectively, of another variation of a cover member that may be used with the optical sensing modules described herein. FIG. 2F is an enlarged view of a portion of the cover member shown in FIG. 2E. The cover member may alternately be referred to herein as a rear cover member or as a rear crystal.

[0015] FIGS. 3A and 3B show top and cross-sectional side views, respectively, of a portion of an optical sensing module as described herein.

[0016] FIG. 4 shows a top view of an optical sensing module, as described herein, that includes multiple emission windows.

[0017] FIGS. 5A-5C show cross-sectional side views of variations of the optical sensing module of FIG. 4.

[0018] FIG. 6 shows an exploded perspective view of an arrangement that includes an aperture layer and a plurality of emission optical elements.

[0019] FIG. 7A shows a cross-sectional side view of an integrated optical component that includes an aperture layer and a plurality of emission optical elements. FIG. 7B shows a variation of an optical sensing module that includes the integrated optical component of FIG. 7A.

[0020] FIG. 8A shows a cross-sectional side view of a variation of an optical sensing module as described herein that includes a coil assembly. FIG. 8B shows an exploded perspective view of the coil assembly of FIG. 8A.

[0021] FIGS. 9A and 8B show cross-sectional side views of variations of optical sensing modules as described herein.

[0022] FIG. 10 shows a cross-sectional side view of a variation of an optical sensing module as described herein.

[0023] FIGS. 11 A-1 1 D show top views of variations of optical sensing modules as described herein that each include a plurality of light emitters and a plurality of light detectors.

[0024] FIGS. 12A-12C show top views of variations of light detectors that may used in the optical sensing modules described herein. FIG. 12D shows a cross- sectional side view of a variation of the light detector of FIG. 12B. FIGS. 12E and 12F show top and cross-sectional side views, respectively, of another variation of a light detector that may be used in the optical sensing modules described herein. FIG. 12G shows a top view of still another variation of a light detector that may be used in the optical sensing modules described herein.

[0025] FIG. 13 shows a top view of a variation of an optical sensing module as described herein that includes a plurality of light emitters and a plurality of light detectors.

[0026] FIGS. 14A and 14B show top and partial cross-sectional views, respectively, of a variation of an emission optical element as described herein that includes a plurality of microlenses.

[0027] FIGS. 15A and 15B show top and partial cross-sectional views, respectively, of a variation of an emission optical element as described herein that includes a plurality of micro-Fresnel optics.

[0028] FIGS. 16A and 16B show top and partial cross-sectional views, respectively, of a variation of an emission optical element as described herein that includes a plurality of microlenses and a plurality of micro-Fresnel optics.

[0029] FIGS. 17A and 17B show top and partial cross-sectional views, respectively, of a variation of a detection optical element as described herein that includes a Fresnel lens with a plurality of concentric teeth.

[0030] FIGS. 18A and 18B show top and partial cross-sectional views, respectively, of a variation of a detection optical element that includes a Fresnel lens with a plurality of radial teeth. FIG. 18C shows a top view of a variation of a detection optical element as described herein that includes a Fresnel lens with a plurality of concentric teeth and a plurality of radial teeth.

[0031] FIG. 19 shows a cross-sectional side view of a variation of an optical sensing module as described herein.

[0032] FIGS. 20A and 20B show top and cross-sectional side views, respectively, of a variation of an optical sensing module as described herein.

[0033] FIG. 21 A shows a perspective view of a variation of a tiered magnet as described herein. FIGS. 21 B-21 E show top views of variations of tiered magnets as described herein.

[0034] FIGS. 22A and 22B show a cross-sectional side view and a top view, respectively, of portions of a variation of an optical sensing module as described herein.

[0035] FIG. 23A shows a perspective view of a variation of a tiered magnet as described herein. FIG. 23B shows a rear view of an optical sensing module that includes the tiered magnet of FIG. 23A.DETAILED DESCRIPTION

[0036] Reference is made herein in detail to representative embodiments that are illustrated in accompanying drawings. It should be understood that the descriptions provided herein are not intended to limit the embodiments to one preferred implementation, and are intended to cover modifications, alternatives, and equivalents as can be included within the spirit and scope of the disclosure and as defined by the appended claims.

[0037] Some embodiments are directed to an optical sensing module, or an electronic device incorporating the optical sensing module, that is configured to perform one or more optical measurements. The optical sensing module is configured to house a light emitter array and a light detector array. Specifically, the optical sensing module may include a cover assembly that defines a plurality of windows, including at least a detection window positioned over the light detector array and one or more emission windows positioned over the light emitter array. Overall, the optical sensing modules described herein may provide for a range of optical sensing capabilities while maintaining a relatively compact form factor.

[0038] Examples of embodiments are discussed herein with reference to FIGS. 1 A-23B. However, those skilled in the art will readily appreciate that the detailed description provided herein with respect to these figures is for explanatory purposes only, and thus should not be construed as limiting.

[0039] FIGS. 1 A and 1 B show front and rear views, respectively, of an electronic device 100, as described herein. For the purposes of this disclosure, the electronic device 100 may be a portable electronic device such as, for example, a wearable electronic device (e.g., a watch or other wearable device, such as a wrist-worn device), a health monitoring device, a mobile phone, a portable computer, a tablet computer, a portable music player, a portable terminal, a wireless charging device, a device accessory, or the like. In the variation shown in FIGS. 1 A and 1 B, the electronic device 100 is configured as a watch, which is sometimes referred to as an electronic watch or a smartwatch.

[0040] The electronic device 100 includes an optical sensing module 102, such as described in more detail herein, and a housing 104. The optical sensing module 102 and the housing 104 may at least partially define an enclosure 105 of the electronic device 100, which may enclose various components of the electronic device 100. While the housing 104 is shown in FIGS. 1 A and 1 B as being formed from a single piece, it should be appreciated that the housing 104 may be formed from multiple individual pieces, if so desired. In some embodiments, at least a portion of the housing 104 is electrically conductive. For example, one or more portions of the housing 104 may be formed of an electrically conductive material. In some instances, the electrically conductive material may include one or more metals and, in some cases, may be a metal alloy (e.g., an iron-based alloy, an aluminum-based alloy, a titanium-based alloy, a magnesium-based alloy, or the like).

[0041] In some variations, the electronic device 100 further includes a front cover 106 that may, along with the optical sensing module 102 and the housing 104, at least partially define the enclosure 105. The front cover 106 is positioned over a display assembly 108, as indicated by dashed lines in FIG. 1A. In some embodiments, the display assembly 108 may be attached to (or may abut) the front cover 106. The display assembly 108 may be configured to produce a graphical output which is transmitted through a transparent portion of the front cover 106. The display assembly 108 may include display components as may be needed to generate the graphical output. For example, the display assembly 108 may be configured as a liquid-crystal display (LCD), a light-emitting diode (LED) display, an LED-backlit LCD display, an organic light-emitting diode (OLED) display, an active layer organic light-emitting diode (AMOLED) display, or the like. In some cases, the display assembly 108 is configured to detect a touch input provided on the front cover 106 (e.g., the display assembly 108 may include a touch-sensitive layer configured to detect a touch input). A display assembly that is configured to both produce a graphical output and detect a touch input on the front cover 106 may be referred to as a touch-sensitive display. The display assembly 108 may also include a display control circuit that is configured to control the operation of the display assembly 108.

[0042] In some embodiments, the front cover 106 is transparent or includes one or more transparent portions over the display assembly 108. For example, the front cover 106 (or a transparent portion thereof) may transmit at least 80% over a visible wavelength range (e.g., the visible spectrum). In some embodiments, this transmission may be at least 85%, 90%, or 95% over the visible spectrum. The front cover 106 may be formed of a glass, a glass ceramic, a ceramic (such as sapphire), or combinations thereof. In some embodiments, the front cover 106 may be formed of one or more layers of a glass, a glass ceramic, a ceramic (such as sapphire), a polymer, or combinations thereof. In addition, the front cover 106 may include one or more coatings (e.g., disposed on a corresponding layer of the front cover 106), such as an exterior coating and / or an interior coating. Exterior coatings may be disposed on a surface of the front cover 106 that faces away from the enclosure 105, and may include, but are not limited to, smudge-resistant (e.g., oleophobic) and anti-reflective coatings. Interior coatings may be disposed on a surface of the front cover 106 that faces an interior of the enclosure 105, and may include, but are not limited to, masking layers.

[0043] Overall, the electronic device 100 defines an exterior that includes a front surface 112 and a rear surface 114 opposite the front surface 112. The exterior of the electronic device 100 may include at least one side surface 116 (as shown in FIG. 1 C) that connects the front surface 112 to the rear surface 114. Depending on the shape of the electronic device 100, the exterior may include a single side surface or multiple side surfaces that connect the front surface 112 to the rear surface 114. In some cases, the front cover 106 (in combination with any exterior surface coatings) may at least partially define the front surface 112 of the electronic device 100 and the optical sensing module 102 may at least partially define the rear surface 114 of the electronic device 100. In these instances, the display assembly 108 may produce a graphical output through the front surface 112 of the electronic device 100, and the optical sensing module 102 may perform optical measurements through the rear surface 114 of the electronic device 100.

[0044] The electronic device 100 may include a band 1 17 that is configured to secure the electronic device 100 to a user. The band 117 may be formed from a single piece, or may include multiple pieces, and may be configured to at least partially encircle a portion of a user’s body. For example, when the electronic device100 is configured as a watch, the electronic device 100 may be worn such that the band 117 and housing 104 at least partially encircle a user’s wrist. Accordingly, the band 117 may hold the housing 104 in place against the user’s wrist.

[0045] The electronic device 100 may further include one or more input systems, such as a set of input systems 110a-110b shown in FIGS. 1 A and 1 B that are configured to receive a physical input from a user. While the electronic device 100 is shown in FIGS. 1 A and 1 B, as having two input systems (e.g., a first input system 110a and a second input system 110b), the electronic device 100 may have any number of input systems as may be desired. Each input system may be configured, for example, as a push button, a touch-activated button (e.g., a capacitive touch button), a dial, crown, or the like. In some instances, an input system may also be capable of performing a bioauthentication operation (e.g., to detect a fingerprint or other identifying information about a user). Each input system may provide one or more dedicated functions (which may vary depending on device operation), such that a user may manipulate the input system to initiate a corresponding function of the electronic device 100. For example, a user may initiate an on-demand optical measurement performed by the optical sensing module 102 by manipulating an input system. Additionally or alternatively, the electronic device 100 may, in response to receiving an input at an input system of the electronic device 100, operate the display assembly 108 to output a graphical output of a measurement performed by the optical sensing module 102.

[0046] In some embodiments, an input system (e.g., the first input system 110a or the second input system 110b) may include an electrode. For example, the electronic device 100 may include a biopotential sensor that utilizes multiple electrodes to measure one or more signals associated with the electrical activity of a user’s body. The electrode associated with the input system may be utilized to perform a measurement with the biopotential sensor. In some embodiments, the biopotential sensor may be configured to measure an electrocardiogram (ECG), an electromyogram (EMG), an electroencephalogram (EEG), electrodermal activity (e.g., skin conductance), combinations thereof, or the like. The biopotential sensor may include one or more electrodes in addition to or instead of an electrode in an input system.

[0047] FIG. 1C shows an exploded perspective view of the electronic device 100, which illustrates the components of the optical sensing module 102. Specifically, the optical sensing module 102 may include a cover assembly 120 and a substrate assembly 130, which collectively house a light detector array 132 and a light emitter array 134. The light detector array 132 includes a plurality of light detectors and the light emitter array 134 may include a plurality of light emitters, such as described in more detail herein with respect to FIGS. 11 A-13. The cover assembly 120 may be attached to the housing 104, and may form a corresponding portion of the enclosure 105 of the electronic device 100. For example, the housing 104 may define a rear opening 118, and the cover assembly 120 may be attached to the housing 104 such that the cover assembly 120 covers the rear opening 118. In some examples, the rear opening 118 is positioned at a center of the rear surface 114, such that the optical sensing module 102 is centrally positioned relative to the rear surface 114 of the electronic device. This may help to reduce ambient light that enters the optical sensing module 102 when the optical sensing module 102 is performing an optical measurement as described herein.

[0048] In some embodiments, the housing 104 may include a ledge 119 that at least partially surrounds the rear opening 118, and the cover assembly 120 may be positioned such that a peripheral portion of the cover assembly 120 is attached to the ledge 119 (e.g., via an adhesive or the like). It should be appreciated that in some instances, the cover assembly 120 may be attached to the ledge 119 via one or more intervening components (e.g., one or more force sensors, one or more gaskets, or the like positioned between the cover assembly 120 and the ledge 119). In some instances, the cover assembly 120 may be attached to housing 104 in a manner that creates a water-tight seal between the cover assembly 120 and the housing 104.

[0049] In this way, the cover assembly 120 may form a portion of the enclosure 105 and may (along with the housing 104, the front cover 106, and any other components that define the enclosure 105 of the electronic device 100) enclose other components of the optical sensing module 102 (such as the substrate assembly 130) within the electronic device 100. Accordingly, the cover assembly 120 may have a first surface that is interior to the enclosure 105 of the electronic device100, and may have a second surface that is exterior to the electronic device 100 (e.g., that forms a corresponding portion of the exterior of the electronic device 100, such as a corresponding portion of the rear surface 114). While the cover assembly 120 is shown in FIG. 1C as having a circular perimeter, it should be appreciated that the perimeter of the cover assembly 120 may have any suitable shape (e.g., oval, square, or the like) as may be desired.

[0050] The cover assembly 120 includes a cover member 121 , which may carry or otherwise support one or more additional components of the cover assembly 120. For example, the cover member 121 may be attached to the housing 104 (e.g., via ledge 119) such that the cover member 121 covers the rear opening 118 defined through the housing 104. The cover member 121 may have a first surface that is interior to the enclosure 105 of the electronic device 100 and may have a second surface that is exterior to the electronic device 100. In this way, the first surface of the cover member 121 may, along with any coatings or optical components supported by the first surface of the cover member 121 , define the first surface of the cover assembly 120. Similarly, the second surface of the cover member 121 may, along with any coatings or optical components supported by the second surface of the cover member 121 , define the second surface of the cover assembly 120. In some instances, the first surface (e.g., the exterior surface) of the cover member 121 may be convex or otherwise contoured. This may help to facilitate contact between the optical sensing module 102 and a user’s skin during an optical measurement. Additionally, in some examples the profile of the cover member 121 may help to align the electronic device 100 relative to a charging device that is placed in contact with the cover assembly 120.

[0051] The cover assembly 120 defines a plurality of windows, each of which allows light to pass through the cover assembly 120. Specifically, the cover assembly 120 defines a detection window 122 that is positioned over the light detector array 132, such that light may enter the optical sensing module 102 through the detection window 122 and may be received by a light detector of the light detector array 132. The cover assembly 120 further defines a set of emission windows 124, each of which is positioned over a corresponding portion of the emitter array. Light emitted by each light emitter of the light emitter array 134 may exit theoptical sensing module 102 through a corresponding emission window of the set of emission windows 124. In the example shown in FIG. 1 C, the cover assembly 120 defines a single emission window 124 that is positioned over the entire light emitter array 134. In other examples, the cover assembly 120 defines a plurality of emission windows, where each emission window of the plurality of emission windows is positioned over a different corresponding set of light emitters of the light emitter array 134. Each set of light emitters may include a single light emitter or a plurality of light emitters positioned under the corresponding emission window.

[0052] In some embodiments, the detection window 122 has an annular shape that at least partially surrounds the set of emission windows 124. In some examples, the detection window 122 is configured as a full annulus that fully surrounds the set of emission windows 124. It may be desirable, depending on the configuration of the cover assembly 120, to optically isolate the detection window 122 from the set of emission windows 124 within the cover member 121 . For example, the cover member 121 may include an optical barrier 123 positioned between the detection window 122 and the set of emission windows 124. The optical barrier 123 may limit optical crosstalk within the cover member 121 (e.g., light that passes from a detection window 122 to an emission window 124, or vice versa, without first exiting the cover member 121).

[0053] In some embodiments, such as in examples where the electronic device 100 includes a biopotential sensor, the cover assembly 120 may include a set of electrodes 125a-125b that are positioned on or supported by the cover member 121 . The set of electrodes 125a-125b may, alone or in combination with other electrodes of the electronic device 100, be used by a biopotential sensor to measure one or more signals during a measurement performed by the biopotential sensor (e.g., an ECG measurement, an EMG measurement, an electrodermal activity measurement, or the like). While the set of electrodes 125a-125b is shown in FIG. 1 C as having two electrodes (e.g., a first electrode 125a and a second electrode 125b), the set of electrodes 125a-125b may in other instances include fewer electrodes (e.g., a single electrode) or more electrodes (e.g., three or more electrodes) supported by the cover member 121 .

[0054] The set of electrodes 125a-125b may be positioned on any suitable portions of the cover member 121 . Specifically, at least a portion of each electrode of the set of electrodes 125a-125b may be positioned on the second surface of the cover member 121 (e.g., external to the electronic device), such that the electrode defines a corresponding portion of the rear surface 114 of the electronic device 100. Accordingly, when the rear surface 114 of the electronic device 100 is positioned in contact with a user’s skin (e.g., the user’s wrist), the set of electrodes 125a-125b may also contact corresponding regions of the user’s skin. Each electrode may have any suitable shape, as may be desired. In the example shown in FIG. 1 C, each of the set of electrodes 125a-125b has an arcuate shape. In some of these examples, such as when the cover member 120 has a circular perimeter, some or all of the set of electrodes 125a-125b may have a semi-circular shape.

[0055] In some examples, some or all of the set of electrodes 125a-125b may extend to a peripheral edge of the cover member 121 . In some cases, the set of electrodes 125a-125b may wrap around the peripheral edge of the cover member 121 , which may facilitate electrical connection or coupling to the set of electrodes 125a-125b via a respective portion of the electrodes 125a-125b that is positioned along an interior surface of the cover member 121 . In some implementations, an electrical via or conductive coupling extends through the cover member 121 to facilitate electrical connection or coupling to the set of electrodes 125a-125b. The biopotential sensor may include a controller (referred to herein as “biopotential sensor controller”) that is configured to control the biopotential sensors to perform measurements using the set of electrodes 125a-125b. Specifically, the biopotential sensor controller may include any suitable combination of hardware, software, and / or firmware as may be necessary to control the various operations of the biopotential sensor. The set of electrodes 125a-125b may be electrically connected to the biopotential sensor controller in any suitable manner. For example, in some instances the electrodes of the set of electrodes 125a-125b may wrap around the perimeter of the cover member 121 , such that a first portion of each electrode is positioned on the first surface of cover member 121 (e.g., internal to the electronic device 100) and a second portion of each electrode is positioned on the second surface of the cover member 121 . In these instances, the second portion of each electrode may be electrically connected to the biopotential sensor controller. In otherexamples, some or all of the set of electrodes 125a-125b may be connected to the biopotential sensor controller using corresponding electrically conductive vias that are formed in the cover member 121 .

[0056] Typically, the set of electrodes 125a-125b are formed from a conductive material that is positioned on (e.g., attached to or deposited on) the cover member 121 . Each of the set of electrodes 125a-125b may be formed from an electrically conductive material, such as a metal or metallic compound. In one example, each of the set of electrodes 125a-125b is formed from a stainless steel or other metal material that is coupled to the cover member 121. In another example, each of the set of electrodes 125a-125b are deposited using a physical vapor deposition (PVD) or other similar process and may include one or more coatings or composition elements that improve the wear resistance and / or electrical conductivity of the electrode surface. Example electrode materials and / or coatings may include aluminum titanium nitride (AITiN) or chromium silicon carbonitride (CrSiCN). AITiN and CrSiCN may provide good resistance to abrasion and corrosion and tend not to place undue stresses on the cover member 121 . One or more of the set of electrodes 125a-125b may be formed by a transparent or optically transmissive conductive material like an indium titanium oxide (ITO) or other similar material. In some implementations, the set of electrodes 125a-125b are formed from a stack or multiple layers of materials, which may include an aluminum oxide (AI2O3) layer, a layer of ITO on the AL2O3 layer, a first layer of silicon dioxide (SiO2) on the AL2O3 layer, a layer of silicon nitride (Si3N4) on the first layer of SiO2, a second layer of SiO2 on the layer of SisIXk, and a layer of diamond-like carbon (DLC), or another hard coating, on the stack. Other stacks or combinations of layers may also be used. For example, the layer of silicon nitride and the second layer of silicon dioxide may be omitted. In another example, the layer of ITO and the first layer of silicon dioxide may be deposited. Each of the layers may be transparent to IR or visible light.

[0057] The cover assembly 120 may include one or more optical elements that are configured to redirect light that passes through a corresponding window of the cover assembly 120. For example, in FIG. 1 C the cover assembly 120 includes a first set of optical elements 126 (also referred to herein as “emission optical elements 126”), each of which is supported by the cover member 121 and is positioned to receivelight emitted by one or more light emitters of the light emitter array 134. Specifically, each emission optical element 126 is positioned over a corresponding emission window 124, such that light emitted by the light emitter array 134 passes through the emission optical element 126 before passing through the corresponding emission window 124. While a single emission optical element 126 is shown in FIG. 1 C, it should be appreciated that the set of emission optical elements 126 may include a plurality of emission optical elements 126, such as in instances where the cover assembly 120 includes a plurality of emission windows 124. Each emission optical element 126 may be configured to shape or otherwise redirect light passing through the emission optical element 126. Examples of emission optical elements are described herein with respect to FIGS. 14A-16B.

[0058] Additionally or alternatively, the cover assembly 120 may include a second set of optical elements 127 (also referred to herein as “detection optical elements 127”), each of which is supported by the cover member 121 and is positioned to receive light collected by a corresponding detection window 122 of the cover assembly 120. Specifically, each detection optical element 127 is positioned over a corresponding detection window 122, such that light collected through the detection window 122 passes through the detection optical element 127 before reaching the light detector array 132. Each detection optical element 127 may be configured to shape or otherwise redirect light passing through the detection optical element 127. Examples of detection optical elements are described herein with respect to FIGS. 17A-18C.

[0059] The cover assembly 120 may include additional coatings or other layers. For example, the cover assembly 120 may include an anti-reflection coating positioned on a surface of the cover member 121 (e.g., on the first surface of the cover assembly 120), which may reduce reflections that occur at an interface of the cover member 121. In instances where the cover assembly 120 includes one or more emission optical elements 126 and / or detection optical elements 127, these optical elements may be attached to the cover member 121 via an adhesive (e.g., an optically clear adhesive).

[0060] The substrate assembly 130 may be attached to the cover assembly 120, such that the substrate assembly 130 is positioned within the electronic device 100behind the cover assembly 120. The substrate assembly 130 includes a set of substrates 131 upon which the light detector array 132 and the light emitter array 134 are mounted. While shown in FIG. 1 C as including a single substrate 131 upon which both the light detector array 132 and the light emitter array 134 are mounted, the substrate assembly 130 may alternatively include a plurality of substrates (e.g., a first substrate upon which the light detectors of the light detector array 132 are mounted and a second substrate upon which the light emitters of the light emitter array 134 are mounted).

[0061] The substrate assembly 130 may be configured to optically isolate the light detector array 132 from the rest of the electronic device. Specifically, it may be desirable to configure the optical sensing module 102 to minimize stray light that is received by the light detector array 132, such that the light detectors of the light detector array essentially only receives light that has entered the optical sensing module 102 from the surrounding environment through the detection window 122 of the cover assembly 120. Accordingly, in some variations the substrate assembly 130 includes a set of barrier walls. For example, the substrate assembly 130 may include an inner barrier wall 133 and outer barrier wall 135. The inner barrier wall 133 may be positioned between the light detector array 132 and the light emitter array 134, and may surround the light emitter array 134. The inner barrier wall 133 may extend between the set of substrates 131 and the cover assembly 120, such that that the optical sensing module 102 defines an inner cavity 136 in which the light emitter array 134 is positioned. Specifically, the set of substrates 131 define a bottom surface of the inner cavity 136, the cover assembly 120 defines a top surface of the inner cavity 136, and the inner barrier wall 133 defines one or more side surfaces of the inner cavity 136.

[0062] The inner barrier wall 133 may be opaque, such that light emitted by the light emitters of the light emitter array 134 does not pass through the inner barrier wall 133. In this way, light emitted by light emitter array 134 may need to exit the electronic device 100 through the cover assembly 120 and reenter the electronic device 100 through the cover assembly 120 in order to be measured by light detectors of the light detector array 132. It should be appreciated that the light detectors of the light detector array 132 each have an operating range that definesthe range of wavelengths across which the light detector array 132 is capable of measuring light. For example, the light detectors of the light detector array 132 may have an operating range that spans the visible spectrum and at least a portion of the infrared spectrum. In one non-limiting example, the light detectors of the light detector array 132 may have an operating range that spans at least between 400 nanometers and 1000 nanometers. The operating range may alternately be referred to herein as an operating range of wavelengths.

[0063] Accordingly, when the term “opaque” is used to describe a component of an optical sensing module as described herein, such a component will block at least 80% of light at each wavelength within the operating range of the light detector array of the optical sensing module. It should be appreciated that, depending on the specifications of the electronic device 100, an opaque component of an optical sensing module may block a higher percentage of light across the operating range of the light detector array (e.g., may block at least 85%, 90%, or 95% of light across the operating range). Similarly, when the term “transparent” is used to describe a component of an optical sensing module as described herein, such a component will pass at least 60% or 65% of light at each wavelength within the operating range of the light detector array of the optical sensing module. It should be appreciated that, depending on the specifications of the electronic device 100, a transparent component of an optical sensing module may pass a higher percentage of light across the operating range of the light detector array (e.g., may pass at least 65% or 70% of light across the operating range or within a portion of the operating range).

[0064] It should also be appreciated that certain components of an optical sensing module may be configured to be “selectively transparent” / ”selectively opaque”. In these instances, a component may be configured to be opaque at a first set of wavelengths within the operating range of the light detector array (e.g., may block at least 80% of light of the first set of wavelengths) and may be transparent at a second set of wavelengths within the operating range of the light detector array (e.g., may pass at least 60% of light of the second set of wavelengths). For example, a particular component may be selectively transparent to light at one or more infrared wavelengths (e.g., at one or more infrared wavelengths emitted by certain light emitters of a light emitter array of the optical sensing module) and may be selectivelyopaque to light in the visible spectrum (e.g., between at least 400 nm and 700 nm). An example of a selectively transparent component is described herein with respect to FIG. 5B.

[0065] Returning to FIG. 1 C, the outer barrier wall 135 may be positioned to surround the light detector array 132, and may be opaque such that the outer barrier wall 135 acts as an optical barrier for an outer periphery of the substrate assembly 130. In some instances, the outer barrier wall 135 may extend between the set of substrates 131 and the cover assembly 120, such that that the optical sensing module 102 defines an outer cavity 137 in which the light emitter array 134 is positioned. In these instances, the set of substrates 131 define a bottom surface of the outer cavity 137, the cover assembly 120 defines a top surface of the outer cavity 137, the inner barrier wall 133 defines one or more inner side surfaces of the outer cavity 137, and the outer barrier wall 135 defines one or more outer side surfaces of the outer cavity 137. The inner barrier wall 133, the outer barrier wall 135, and the set of substrates 131 may provide optical isolation to the light detector array 132, such that the light detector array 132 effectively measures only light that has passed through the cover assembly 120 via the detection window 122.

[0066] In some instances, the inner barrier wall 133 and / or the outer barrier wall 135 may be formed as separate components from the set of substrates 131 and cover assembly 120. For example, FIGS. 8A and 8B show an example of an optical sensing module in which a portion of a coil assembly forms a portion of an outer barrier wall. Additionally or alternatively, the inner barrier wall 133 and / or the outer barrier wall 135 may be at least partially formed from the set of substrates 131 and / or the cover member 121 , such as described in more detail herein.

[0067] In some examples, the optical sensing module 102 may further include a controller substrate 140 that is configured to house a controller 144 (also referred to herein as “optical sensor controller 144”). The optical sensor controller 144 may be any suitable combination of hardware, software, and / or firmware as may be necessary to control the various operations of the optical sensing module 102. For example, the optical sensor controller 144 may operate one or more light emitters of the light emitter array 134 to generate light as part of a given optical measurement,and may operate one or more light detectors of the light detector array 132 to measure light as part of the optical measurement.

[0068] In some examples, the optical sensor controller 144 may include one or more processors and memory. Memory can include one or more non-transitory computer-readable storage mediums, for storing computer-executable instructions, which, when executed by one or more computer processors, for example, can cause the computer processors to perform one or more optical measurements as described herein. A computer-readable storage medium can be any medium that can tangibly contain or store computer-executable instructions for use by or in connection with the instruction execution system, apparatus, or device. In some examples, the storage medium is a transitory computer-readable storage medium. In some examples, the storage medium is a non-transitory computer-readable storage medium. The non- transitory computer-readable storage medium can include, but is not limited to, magnetic, optical, and / or semiconductor storages. Examples of such storage include magnetic disks, optical discs, as well as persistent solid-state memory such as flash, solid-state drives, and the like. It should be appreciated that different components of the optical sensor controller 144 may be distributed throughout the electronic device 100, such that certain components of the optical sensor controller 144 are carried by the controller substrate 140 and other components of the optical sensor controller 144 are carried by different potions of the electronic device 100.

[0069] It should also be appreciated that while the optical sensor controller 144 may operate the optical sensing module 102 to perform optical measurements, the resulting measurement signals generated by the optical sensing module 102 may undergo certain signal processing operations or analysis by other processing circuitry. For example, the optical sensor controller 144 may transmit measurement signals generated by the optical sensing module 102 to another processor of the electronic device 100 for further signal processing or analysis. In other examples, the electronic device 100 may transmit (e.g., using a wireless communication protocol) the measurement signals generated by the optical sensing module 102 to another electronic device for further signal processing or analysis.

[0070] In some variations, each of the set of substrates 131 of the substrate assembly 130 and the controller substrate 140 are formed as printed circuit boards(PCBs) that facilitate electrical connections between the optical sensor controller 144 and each of the light detector array 132 and the light emitter array 134. For example, the controller substrate 140 may include a set of electrical contacts 142 that may be electrically connected to a corresponding set of electrical contacts (not shown) on the set of substrates 131 . The optical sensor controller 144 may be electrically connected to the set of electrical contacts 142 within the controller substrate 140, which may allow for power and / or control signals to be routed between the optical sensor controller 144 and the set of substrates 131 . Similarly, the set of electrical contacts on the set of substrates 131 may allow for power and / or control signals to be routed between the controller substrate 140 and each of the light detector array 132 and the light emitter array 134. The set of substrates 131 may be attached to the controller substrate 140 in any suitable manner (e.g., via the physical connection between the corresponding electrical contacts, via an adhesive, via one or more mechanical fasteners, combinations thereof, or the like).

[0071] In some examples, the electronic device 100 may include one or more magnets that may help to hold the electronic device 100 in place and / or align the electronic device 100 relative to a charging device (not shown) that is used to provide power to the electronic device 100 (e.g., to charge a battery of the electronic device 100). In some variations, the electronic device includes a first magnet 160 that may be positioned behind the optical sensing module 102, such that the substrate assembly 130 is positioned between the first magnet 160 and the cover member 121. In some of these variations, the controller substrate 140 may define an aperture 146 extending through the controller substrate 140. In these variations, the first magnet 160 may be positioned at least partially inside of the aperture 146 (e.g., abutting and / or attached to the set of substrates 131 of the substrate assembly 130), which may position the first magnet 160 closer to the rear surface 114 of the electronic device 100.

[0072] Additionally or alternatively, the electronic device 100 may include a second magnet 162 that is positioned inside of the optical sensing module 102. In some examples, the second magnet 162 is positioned within the inner cavity 136, such that the second magnet 162 is positioned between the set of substrates 131 and the cover assembly 120. For example, the second magnet 162 may be attached to thecover member 121 (e.g., directly or indirectly via one or more intervening components), such as described in more detail herein with respect to FIG. 19.

[0073] In some examples, the electronic device 100 includes a coil assembly 150 that is configured to facilitate wireless power transfer between the electronic device 100 and a second electronic device (e.g., a charging device). For example, a charging device may induce a current in a coil of the coil assembly 150 using alternating electromagnetic fields, and this current may be used to power the electronic device 100, for example to charge a battery of the electronic device 100. Depending on the placement of the coil assembly 150 within the electronic device 100, this inductive charging may be performed through at least a portion of the optical sensing module 102 (e.g., through a portion of the cover assembly 120, including the set of electrodes 125a-125b). In some examples, the coil assembly 150 may form a portion of the optical sensing module 102 (e.g., a portion of the outer barrier wall 135, such as described herein with respect to FIGS. 8A and 8B).

[0074] FIGS. 2A and 2B show a top view and cross-sectional side view (taken along line 2B-2B), respectively, of a variation of a cover member 200 that may be used with the optical sensing modules described herein. FIG. 2C shows an enlarged cross-sectional side view of a region 230 of FIG. 2B. In some examples, the cover member 200 may be used as the cover member 121 of the cover assembly 120 of the electronic device 100 of FIGS. 1 A-1 C. The cover member 200 may include a set of opaque portions and a set of transparent portions (which are shown in FIGS. 2B and 2C without cross-hatching to assist in visualization of the cover member 200).

[0075] The cover member 200 may be integrally formed from the set of opaque portions and the set of transparent portions. For example, the transparent portions of the cover member may be bonded to the opaque portions to form an integral cover member. The bonding between the transparent and the opaque portions may give the cover member 200 a seamless appearance, as discussed in more detail below.

[0076] Specifically, the cover member 200 may include a set of inner transparent portions 202 and an outer transparent portion 204, and an inner opaque portion 206 that optically isolates the set of inner transparent portions 202 from the outer transparent portion 204. The inner opaque portion 206 surrounds each of the set ofinner transparent portions 202, and the outer transparent portion 204 may surround the inner opaque portion 206. In this way, the outer transparent portion 204 may also surround each of the inner transparent portions 202. While the set of inner transparent portions 202 is shown in FIGS. 2A-2C as including a single inner transparent portion 202, it should be appreciated that in other variations the set of inner transparent portions may include a plurality of inner transparent portions, such as described herein with respect to FIGS. 2D-2F. The set of inner transparent portions 202 may alternately be referred to herein as a set of first window portions or a first window portion in the example of a single inner transparent portion 202. The outer transparent portion 204 may alternately be referred to as a second window portion. The inner opaque portion 206 may alternately be referred to herein as a barrier portion, a first barrier portion, or as a first optical barrier.

[0077] In some variations, the cover member 200 further includes an outer opaque portion 208 that at least partially surrounds the outer transparent portion 204. In some variations, the outer opaque portion 208 may extend to a perimeter of the cover member 200, and thus may at least partially define (and in some instances, fully define) the perimeter of the cover member 200. In the variation shown in FIGS. 2A-2C, the outer opaque portion 208 fully surrounds the outer transparent portion 204. In these variations, the outer transparent portion 204 may form an annulus that surrounds the inner opaque portion 206. In examples in which the set of inner transparent portions 202 includes a single inner transparent portion 202, the inner opaque portion 206 may also form an annulus that surrounds the inner transparent portion 202.

[0078] When the cover member 200 is incorporated into a cover assembly, as described herein, the outer transparent portion 204 may at least partially define a detection window of the cover assembly. Similarly, each of the set of inner transparent portions 202 may at least partially define one or more emission windows of the cover assembly. In these instances, the inner opaque portion 206 may act as an optical barrier, within the cover member 200, between the detection window and the set of emission windows of the cover assembly.

[0079] As used herein, the outer opaque portion 208 may also be referred to herein as an outer barrier portion or an outer barrier ring. The outer opaque portion208 may also be referred to as an outer non-window portion. Similarly, the inner opaque portion 206 may be referred to herein as an inner barrier portion, inner barrier ring, or inner non-window portion. Each of the outer opaque portion 208 and the inner opaque portion 206 may have a round or rounded profile. In the current example, the round profile is an annular shape. In some examples, the inner opaque portion 206 defines a first annular shape and the outer transparent portion 204 defines a second annular shape.

[0080] The opaque portions of the cover member 200 (e.g., the inner opaque portion 206 and the outer opaque portion 208) may include or otherwise be formed by one or more opaque materials, whereas the transparent portions of the cover member 200 (e.g., the set of inner transparent portions 202 and the outer transparent portion 204) may be formed from one or more transparent materials. A transparent material may have a coefficient of thermal expansion that is similar to that of the opaque material in order to facilitate bonding between these materials. In some variations, each of the transparent materials and each of the opaque materials is a ceramic material and the cover member 200 is a ceramic cover member.

[0081] In some variations, the cover member 200 is a zirconia cover member. In some variations, the set of inner transparent portions 202, the inner opaque portion 206, the outer transparent portion 204, and the outer opaque portion 208 are each formed from a respective zirconia material. As an example, the inner opaque portion 206 (alternately, first barrier portion) is formed from a first zirconia material, the set of inner transparent portions 202 (alternately, first window portion) is formed from a second zirconia material, the outer transparent portion 204 (alternately, second window portion) is formed from a third zirconia material, and the outer opaque portion 208 (alternately, second barrier portion) is formed from a fourth zirconia material. Described differently, the set of inner transparent portions 202 may be formed from a first transparent zirconia material, the outer transparent portion 204 may be formed from a second transparent zirconia material, the inner opaque portion 206 may be formed from a first opaque zirconia material and the outer opaque portion 208 may be formed from a second opaque zirconia material. In some variations, each of the first and second transparent zirconia materials may be a same zirconia material (e.g., a same transparent polycrystalline zirconia material)and / or each of the first and second opaque zirconia materials may be a same zirconia material (e.g., a same opaque polycrystalline zirconia material). Each of the respective zirconia materials may be a polycrystalline zirconia material. As referred to herein, a polycrystalline zirconia material predominantly includes zirconia (zirconium oxide) but may also include one or more other components such as another oxide (e.g., yttrium oxide and / or aluminum oxide), a coloring agent, a processing agent, or combinations of these. In some examples, the additional oxide (e.g., a yttrium oxide) may be used to stabilize a desired crystal phase within the zirconia material and is included within the zirconia crystals. Suitable coloring agents include, but are not limited to, a pigment that absorbs one or more light wavelengths emitted by the light emitter array and / or within the operating range of the light detector array.

[0082] The transparent portions of the cover member 200 may be configured to have a sufficiently high transmittance for each of the light wavelengths emitted by the light emitter array and across the operating range of the light detector array. In some variations, the total transmittance of each of the set of inner transparent portions 202 is at least 60% or at least 65% for each of the light wavelengths emitted by the light detector array. The total transmittance of the outer transparent portion may be at least 60% or at least 65% across the operating range of the light detector array and / or for select wavelengths within this operating range. In additional variations the total transmittance of a given transparent portion of the cover member may be 70% or more for one or more light wavelengths emitted by the light emitter array and / or within the operating range of the light detector array. These transmittance values may be measured before any coatings (e.g., an anti-reflective coating) are applied to the cover member. The transparent portions of the cover member may be substantially dense to provide these levels of transmittance. As referred to herein, a transparent material and a transparent portion of the cover member 200 formed from the transparent material transmits light in a regular fashion. Although the transparent material may produce some scattering of transmitted light, the extent of scattering is low enough to be compatible with other components of the optical sensing module. Other optical properties of the transparent portions of the cover member 200 include, but are not limited to, the refractive index. In some variations, the refractive index of the transparent portions of the cover member 200 is in a range from 2.1 to 2.3. Adielectric constant of the transparent portions of the cover member may be in a range from about 30 to 34 in a frequency range from 5 GHz to 40 GHz.

[0083] The opaque portions of the cover member 200 typically have a lower transmittance than the transparent portions. In some variations, the opaque portions may have a transmittance that is less than or equal to 5%, less than or equal to 1 %, less than or equal to 0.1%, or less than or equal to 0.01 % for each of the light wavelengths emitted by the light emitter array and / or across the operating range of the light detector array. The opaque portions may alternately be described in terms of their optical density, which is equal to negative 1 multiplied by the logarithm to base 10 of the percentage transmittance divided by 100. In some variations, the opaque portions of the cover member may have an optical density greater than or equal to 2. In one example, the optical density is within a range from 2 to 6. In another example, the optical density may be greater than or equal to 3 and may be within a range from 3 to 6. The optical density (OD) values may be unitless or they may be referenced with respect to a measurement thickness of 1 mm. Thus, the OD may be greater than or equal to 2 per mm, greater than or equal to 3 per mm, range from 2 to 6 per mm, or range from 3 to 6 per mm thickness. In cases where the optical density depends on the thickness, the optical density at a given location of the optical barrier may depend on the local thickness. The optical density values may be applicable for each of the light wavelengths emitted by the light emitter array and / or within the operating range of the light detector array. In some cases, the opaque portions of the cover member 200 include an additive such as a coloring agent that contributes to the opacity of these portions of the cover member. For example, the inclusion of the additive may contribute to absorption of one or more light wavelengths emitted by the light emitter array and / or within the operating range of the light detector array. The dielectric constant of the opaque portions of the cover member may be greater than or equal to the dielectric constant of the transparent portions of the cover member, and may be up to 38 in a frequency range from 5 GHz to 40 GHz.

[0084] The cover member 200 may be a monolithic or unitary structure. For example, the cover member may be integrally formed or may be described as an integral structure. As used herein, the term “integrally formed” may be used to referto a structure in which two or more ceramic materials are bonded together using a co-sintering, diffusion bonding, or other similar technique. In some variations, the bond between the two or more ceramic materials does not rely on a separate adhesive or other similar bonding agent. In some cases, the two or more ceramic materials are coupled or adhered using a separate adhesive or bonding agent. Further, in some instances, the two or more ceramic materials are also mechanically interlocked by an undercut or other physical feature in one or both of the ceramic materials. The mechanical interlock may also be created due to micro-features or textures in one or both of the ceramic materials. The bonding between the different zirconia materials of the cover member may produce a cover member that cannot be readily taken apart without destroying its integrity.

[0085] In some variations, the opaque portions of the cover member 200 are formed from a first polycrystalline zirconia material (alternately, a first zirconia material) and the transparent portions of the cover member 200 are formed from a second polycrystalline zirconia material (e.g., a second zirconia material). Each of the first polycrystalline zirconia material and the second polycrystalline zirconia material may be formed at least in part by sintering of fine zirconia crystals. Furthermore, chemical bonding at the interfaces between the first polycrystalline zirconia material and the second polycrystalline zirconia material may be produced at least in part through solid-state diffusion bonding. The interface between the first polycrystalline zirconia material and the second polycrystalline zirconia material may be referred to as a diffusion-bonded interface. In one example, a first portion of the cover member 200, formed from the first polycrystalline zirconia material, may be described as integrally formed with a second portion of the cover member 200, formed from the second polycrystalline zirconia material, due to a co-sintering or diffusion bonding process.

[0086] Since both the materials being bonded are polycrystalline zirconia materials, an interlayer may be omitted, and the diffusion-bonded interface may provide a seamless appearance. The diffusion bonding may be produced using one or more of a sintering operation, a hot-pressing operation, or the like. The coefficient of thermal expansion of the first and the second polycrystalline zirconia material maybe sufficiently matched so that the interfaces retain their integrity upon cooling from elevated process temperatures.

[0087] In some variations, the cover member 200 is a component or member in which the opaque zirconia material and the transparent zirconia material are molded in a single- or multi-step molding operation(s) and may, therefore, be referred to as a co-molded cover component or member. In some cases, the process for making the cover member 200 includes two or more ceramic injection molding operations. Generally, each injection molding operation may be used to form a portion of the cover member 200 by injecting a respective precursor material to form a respective structure and / or supplement an existing structure. For example, the process may form a first workpiece from a precursor of the opaque zirconia material at least in part through a first ceramic injection molding operation. In some cases, the precursor of the opaque zirconia material is injected in a first and second ceramic injection molding operation to form the first workpiece. The first workpiece may define recesses into which a precursor of the transparent zirconia material is introduced in a second ceramic injection molding operation. A second workpiece is formed by one or more additional injection molding operations in which the precursor of the transparent zirconia material is introduced to the first workpiece. The second injection molding operation may produce close contact between the precursor of the transparent zirconia material and the material of the first workpiece. In some implementations, one or more additional injection molding operations are performed to inject the precursor of the opaque zirconia material into an existing structure. The resulting workpiece typically undergoes additional processing operations to form the cover member 200. Each of the respective injection molding operations can contribute to formation of a high-quality interface between the opaque and transparent zirconia materials in the finished cover member 200. For example, the process for making the cover member 200 may result in a transparent portion of the cover member being “molded to” an adjacent opaque portion so that it closely conforms to that opaque portion. Additional operations in the process for making the cover may include one or more of a binder removal operation from a precursor of the zirconia material, a sintering operation, a pressure assisted consolidation operation (e.g., hot isostatic pressing), a machining operation, a polishing operation, and coating operation.

[0088] The first and the second polycrystalline materials may differ with respect to the crystal phases present in the respective materials. In some variations, the second polycrystalline material may have a greater concentration of cubic phase zirconia crystals than the first polycrystalline material. In some cases, the second polycrystalline material may predominantly include cubic phase zirconia crystals while the first polycrystalline material may predominantly include tetragonal phase zirconia crystals. In some examples, the second polycrystalline material includes at least 90%, at least 95%, at least 98%, or at least 99% of the cubic phase zirconia crystals (alternately, cubic zirconia phase). X-ray diffraction may be used to analyze the crystal phase(s) present in a given polycrystalline material. The higher concentration of cubic phase zirconia crystals in the second polycrystalline material may provide a transmittance of at least 60%, at least 65%, or at least 70% for one or more light wavelengths emitted by the light emitter array and / or within the operating range of the light detector array.

[0089] The cover member 200 may define an interior surface 210, which may be interior to an optical sensing module incorporating the cover member 200, and may define an exterior surface 212, which may be exterior to the optical sensing module incorporating the cover member 200. In some examples, each of the set of inner transparent portions 202, the outer transparent portion 204, the inner opaque portion 206, and the outer opaque portion 208 may extend through the cover member 200 between the interior surface 210 and the exterior surface 212. The inner opaque portion 206 may define a corresponding interface with each inner transparent portion 202. For example, when the cover member 200 includes a single inner transparent portion 202 as shown in FIGS. 2A-2C, cover member 200 may include a first interface 214 between the inner opaque portion 206 and the inner transparent portion 202. The inner opaque portion 206 is bonded to the inner transparent portion 202 at the first interface 214, for example through chemical bonding. For example, an inner face of the inner opaque portion 206 is bonded to the inner transparent portion 202. In some of these embodiments, the first interface 214 may have a taper, draft, or flare with respect to an interior surface 210 of the cover member 200. The first interface 214 may also be described as having a conical shape that expands outward with respect to the interior surface of the cover member 200. In these examples, a width of the inner transparent portion 202 may increase (e.g., taper orflare outward) between the interior surface 210 and the exterior surface 212 of the cover member 200. In these instances, one or more emission windows defined in the inner transparent portion 202 may similarly flare or taper outward, which may allow for a light emitter array to introduce light into a larger tissue area while maintaining a compact form factor of the optical sensing module. As described herein, the flared or tapered portions may also be described as having a tapered or flared cross-section. For example, the inner transparent portion 202 may define a first tapered crosssection and the outer transparent portion 204 may define a second tapered crosssection. In the example of FIG. 2C, the first interface 214 defines a first angle 01 with respect to a normal (e.g., a first normal) to the interior surface 210.

[0090] The cover member 200 may include a second interface 216 between the inner opaque portion 206 and the outer transparent portion 204. The inner opaque portion 206 is bonded to the outer transparent portion 204 at the second interface 216, for example through chemical bonding. For example, an outer face of the inner opaque portion 206 is bonded to an inner face of the outer transparent portion 204. In some of these embodiments, the second interface 216 may have a taper, draft, or flare with respect to an interior surface 210 of the cover member 200. The second interface 216 may also be described as having a conical shape that expands outward with respect to the interior surface of the cover member 200. When the second interface 216 and the first interface 214 are tapered as shown in this example, a width of the inner opaque portion may decrease (e.g., taper or flare inward) as the inner opaque portion extends from the interior surface 210 to the exterior surface 212 of the cover member 200. As shown in FIG. 2C, the second interface 216 defines a second angle 62 with respect to a normal (e.g., a second normal) to the interior surface 210. The second angle 62 may be the same as the first angle 0i or may be different from the first angle 01. In some variations, the second angle 02 is less than the first angle 01 and a third angle 03, as shown in the example of FIG. 2C. Each of the first angle 01 and the second angle 02 may be an acute angle.

[0091] The inner opaque portion 206 may be configured to be sufficiently robust to withstand various operations used to make the cover member, such as injection molding and pressure-assisted consolidation operations, while still being compatiblewith an optical sensing module having a compact form factor. In some variations, the cover member 200 is designed so that an aspect ratio of the inner opaque portion 206 (e.g., a ratio of a width to a thickness) is not overly small while still providing a relatively small spacing between the inner transparent portion(s) 202 and the outer transparent portion 204. In examples where the set of inner transparent portions 202 includes a single inner transparent portion 202, the top width wt defines a minimum spacing between the inner transparent portion 202 and the outer transparent portion 204. In some variations, the inner opaque portion 206 has a cross-sectional shape that is tapered or flared so that the width of the inner opaque portion 206 is different at the exterior surface 212 and the interior surface 210 of the cover member 200. In some cases, the inner opaque portion 206 defines a top width wt at the exterior surface 212 and a bottom width Wb at the interior surface 210 that is greater than the top width wt. Furthermore, the outward flaring of the inner transparent portion 202 and the outer transparent portion 204 can create an opposing flaring of the inner opaque portion 206 in which the width of the inner opaque portion 206 decreases between the interior surface 210 and the exterior surface 212 of the cover member 200. These features of the shape of the inner opaque portion 206 can help provide resistance to undesirable modes of deformation during one or more operations of the manufacturing process of the cover member 200. In some variations, the minimum spacing between the inner transparent portion 202 and the outer transparent portion 204 is greater than 0.5 mm and less than 3 mm, or may be in a range from 0.5 mm to 2 mm, or from 1 mm to 2 mm. The minimum spacing between the inner transparent portion 202 and the outer transparent portion 204 may be less than a maximum thickness of the inner opaque portion 206. In some variations, the thickness of the inner opaque portion 206 is in a range from 1 mm to 3 mm.

[0092] In variations where the cover member 200 includes an outer opaque portion 208, cover member 200 may include a third interface 218 between the outer opaque portion 208 and the outer transparent portion 204. The outer opaque portion 208 may be chemically bonded to the outer transparent portion 204 at the third interface 218. The distance between the second interface 216 and the third interface 218 may define a width of the outer transparent portion 204. In some variations, the cover member 200 is configured such that a width of the outer transparent portion 204 may increase (e.g., flare outward) between the interior surface 210 and theexterior surface 212 of the cover member 200. For example, the second interface 216 may be angled toward the center of the cover member 200 and / or the third interface 218 may be angled away from the center of the cover member 200. In the example of FIG. 2C, the third interface 218 defines an angle 03 with respect to a normal (e.g., a third normal) to the interior surface 210. The third angle 03 may be the same as the first angle 01 and / or the second angle 02 or may be different from each of the first angle 01 and the second angle 02. Each of first angle 01 , the second angle 02, and the third angle 03 may be an acute angle. In some variations, the second angle 02 is less than each of the first angle 01 and the third angle 03, as shown in the example of FIG. 2C. In some variations, each of the first angle 01, the second angle 02, and the third angle 03 is in a range from 0.5 degrees to 20 degrees, 1 degree to 20 degrees, from 5 degrees to 15 degrees, or from 10 degrees to 20 degrees. In some cases, each of the first angle 01, the second angle 02, and the third angle 03 is greater than a draft angle that would typically be used in a ceramic injection molding process, such as a draft angle in a range from about 0.5 degrees to about 5 degrees.

[0093] In some variations, one or more coatings may be applied to the cover member 200, for example an interior coating (e.g., positioned on the interior surface 210 of the cover member 200) and / or an exterior coating (e.g., positioned on the exterior surface 212 of the cover member 200). For example, as shown in FIG. 2C, an anti-reflective coating 220 may be deposited on the interior surface 210 of the cover member 200. The anti-reflective coating 220 may reduce reflections that might otherwise occur as light enters or exits transparent portions of the cover member 200. In some variations, the anti-reflective coating 220 may cover the entire interior surface 210 of the cover member 200. In other examples, the anti-reflective coating 220 may be patterned to selectively cover a portion of the interior surface 210. For example, a first portion of the anti-reflective coating 220 may be positioned to cover the inner transparent portion 202, and a second portion of the anti-reflective coating 220 may be positioned to cover the outer transparent portion 204.

[0094] In some variations, the anti-reflective coating may be formed from multiple layers. The anti-reflective coating may be an inorganic anti-reflective coating, with each of the layers formed from an inorganic material. For example, each of thelayers of the anti-reflective coating may be formed from an inorganic dielectric material. Examples of inorganic materials suitable for the anti-reflective layer include, but are not limited to, oxides such as silicon oxides and metal oxides, nitrides such as silicon nitrides and metal nitrides, and oxynitrides such as silicon oxynitrides. The layers of the anti-reflective coating may be configured to limit angle dependency of the performance of the anti-reflective coating. The layers of the anti-reflective coating may be formed using a physical vapor deposition technique.

[0095] FIGS. 2D and 2E show a top view and cross-sectional side view (taken along line 2E-2E), respectively, of a variation of a cover member 240 that may be used with the optical sensing modules described herein. FIG. 2F shows an enlarged cross-sectional side view of a region 250 of FIG. 2E. In some examples, the cover member 240 may be used as the cover member 121 of the cover assembly 120 of the electronic device 100 of FIGS. 1A-1 C. The cover member 240 may be configured and labeled the same as the cover member 200 of FIGS. 2D and 2E, except that the cover member 240 includes a set of inner transportation portions that includes a plurality of inner transparent portions 242a-242h. In these variations, the inner opaque portion 206 surrounds each inner transparent portion of the plurality of inner transparent portions 242a-242h. Accordingly, the inner opaque portion 206 may optically isolate the plurality of inner transparent portions 242a-242h from the outer transparent portion 204, and may also optically isolate the plurality of inner transparent portions 242a-242h from each other (e.g., the inner transparent portion 242a is optically isolated from inner transparent portions 242b-242h, the inner transparent portion 242b is optically isolated from inner transparent portions 242a and 242c-242h, and so on).

[0096] The inner opaque portion 206 may form a corresponding interface between the inner opaque portion 206 and each inner transparent portion of the plurality of inner transparent portions 242a-242h. For example, an interface 234 between the inner opaque portion 206 and a first inner transparent portion 242a is shown in FIG. 2F. The corresponding interface (e.g., interface 234) between the inner opaque portion 206 and an inner transparent portion (e.g., the first inter transparent portion 242a) may surround that inner transparent portion. In some instances, the corresponding interface may be angled away from a center of the inner transparentportion, such that a width of an inner transparent portion may increase in width between an interior surface 210 of the cover member 240 and an exterior surface 212 of the cover member 240. In the example of FIG. 2F, the interface 234 defines an angle 01a with respect to a normal to the interior surface 210. In some variations, the angle 0iahas similar values to those previously described with respect to the angle 01 of FIG. 20. The angles 02 and 03 of FIG. 2F may have similar values as the angles 02 and 03 described with respect to FIG. 20. In some variations, the plurality of inner transparent portions 242a-242h may be radially arranged around a portion of the cover member 240 (e.g., radially arranged around a center of the cover member 240). For example, the plurality of inner transparent portions 242a-242h may be arranged in a circular pattern, such that each of the plurality of inner transparent portions 242a-242h is positioned such that a circle (not shown) may be drawn that intersects each of the plurality of inner transparent portions 242a-242h. In some of these variations, each of the inner transparent portions 242a-242h is positioned at a common distance from a point on the cover member 240 (e.g., the center of the cover member 240).

[0097] In some instances, the plurality of inner transparent portions 242a-242h and the outer transparent portion 204 are concentrically arranged, such that the plurality of inner transparent portions 242a-242h and the outer transparent portion 204 are centered around a common point. Accordingly, each inner transparent portion of the plurality of inner transparent portions 242a-242h may be separated from the outer transparent portion 204 by a first common distance di. In these instances, the first common distance di represents the shortest distance between each of the plurality of inner transparent portions 242a-242h and the outer transparent portion 204. While the first common distance di is only labeled in FIG. 2D for inner transparent portions 242b and 242c, it should be appreciated that the remaining inner transparent portions of the plurality of inner transparent portions 242a-242h may be separated from the outer transparent portion 204 by the first common distance di.

[0098] In some embodiments, the cover member 240 may include one or more additional transparent portions, in addition to the plurality of inner transparent portions 242a-242h, that are surrounded by the outer transparent portion 204. Forexample, the cover member 240 may include a center transparent portion 260 (the boundaries of which are depicted by dashed lines in FIGS. 2D and 2E) that is positioned within the cover member 240 such that the outer transparent portion 204 surrounds the center transparent portion 260. The center transparent portion 260 may be positioned such that the plurality of inner transparent portions 242a-242h are radially arranged around the center transparent portion 260. In some of these variations, such as when the plurality of inner transparent portions 242a-242h are arranged in a circular pattern, each of the plurality of inner transparent portions 242a-242h may be separated from the center transparent portion 260 by a second common distance c . In these instances, the second common distance ^represents the shortest distance between each of the plurality of inner transparent portions 242a-242h and the center transparent portion 260. While the second common distance c is only labeled in FIG. 2D for inner transparent portions 242b and 242c, it should be appreciated that the inner transparent portions of the plurality of inner transparent portions 242a-242h may be separated from the center transparent portion 260 by the second common distance cfe.

[0099] FIGS. 3A and 3B show a top view and a cross-sectional side view (taken along line 3B-3B), respectively, of a portion of an optical sensing module 300 as described herein. Specifically, the optical sensing module 300 includes a cover assembly 320 that defines an annular detection window 322 that surrounds a single emission window 324. The cover assembly 320 further includes an inner optical barrier 323 positioned between the annular detection window 322 and the emission window 324. In some instances, the cover assembly 320 further includes an outer optical barrier 328 that surrounds the annular detection window 322. The annular detection window 322 is positioned over a light detector array 332 and the emission window 324 is positioned over a light emitter array 334. Accordingly, light emitted by light emitters of the light emitter array 334 may exit the optical sensing module 300 through the emission window 324, and the light measured by the light detectors of the light detector array 332 may enter the optical sensing module 300 through the annular detection window 322.

[0100] In the variation shown in FIGS. 3A and 3B, the cover assembly 320 may include the cover member 200 of FIGS. 2A-2C. In these instances, the innertransparent portion 202 of the cover member 200 may at least partially define the emission window 324, and the outer transparent portion 204 of the cover member 200 may at least partially define the annular detection window 322. In other words, light that exits the optical sensing module 300 through the emission window 324 passes through the inner transparent portion 202 of the cover member 200, and light that enters the optical sensing module 300 through the annular detection window 322 passes through the outer transparent portion 204 of the cover member 200. In these variations, the inner opaque portion 206 of the cover member 200 forms the inner optical barrier 323. Additionally, the outer opaque portion 208 of the cover member 200 may form the outer optical barrier 328.

[0101] The optical sensing module 300 further includes a substrate assembly 330 that includes a set of substrates 331 upon which the light detector array 332 and the light emitter array 334 are mounted. The substrate assembly 330 further includes an inner barrier wall 333 and an outer barrier wall 335 that each extend between the set of substrates 331 and the cover assembly 320. The set of substrates 331 , the inner barrier wall 333, and the outer barrier wall 335 may each be configured in any manner as described herein with respect to the electronic device 100 of FIGS. 1 A- 1 C, and may at least partially define an inner cavity 336 (e.g., in which the light emitter array 334 is positioned) and an outer cavity 337 (e.g., in which the light detector array 332 is positioned).

[0102] The optical sensing module 300 may include an emission optical element326 that is positioned in the inner cavity 336 and attached to the interior surface 210 of the cover member 200. The emission optical element 326 may be positioned over the emission window 324 (e.g., over the inner transparent portion 202 of the cover member 200), such that light emitted by any light emitters of the light emitter array 334 passes through the emission optical element 326 before passing through the emission window 324. Similarly, the optical sensing module 300 may include a detection optical element 327 that is positioned in the outer cavity 337 and attached to an interior surface 210 of the cover member 200. The detection optical element327 may be positioned over the annular detection window 322, such that light collected through the annular detection window 322 passes through the detectionoptical element 327 before reaching the light detectors of the light detector array 332.

[0103] In the variation shown in FIGS. 3A and 3B, the inner barrier wall 333 and the outer barrier wall 335 are formed as separate components from the set of substrates 331 and the cover member 200. For example, the inner barrier wall 333 and the outer barrier wall 335 may each be formed as individual pieces (e.g., via injection molding), and may each be attached to the set of substrates 331 and the cover member 200 (e.g., via corresponding adhesive layers). Accordingly, the inner barrier wall 333 and the outer barrier wall 335 may act to attach the set of substrates 331 to the cover member 200.

[0104] In some variations, the optical sensing module 300 may include a set of electrodes 325a-325b, such as described herein with respect to FIGS. 1A-1 C. In these variations the set of electrodes 325a-325b may be supported by the cover member 200. Some or all of these electrodes may be deposited on corresponding opaque portions of the cover member 200. For example, in the variation shown in FIG. 3A, one or more electrodes (e.g., a first electrode 325a and a second electrode 325b) may be positioned to cover corresponding portions of the outer opaque portion 208 of the cover member 200. By placing electrodes over an opaque portion of the cover member 200, these electrodes (which may have relatively high reflectivity) may be placed close to the annular detection window 322 and / or emission window 324 without negatively impacting the operation of the optical sensing module 300.

[0105] While the cover assembly 320 of the optical sensing module 300 of FIGS. 3A and 3B includes a single emission window 324, it should be appreciated that other examples of the optical sensing modules described herein may include a plurality of emission windows. For example, FIG. 4 shows a top view of a variation of an optical sensing module 400 as described herein. The optical sensing module 400 includes a cover assembly 420 that defines an annular detection window 422 that surrounds a plurality of emission windows 424a-424h. The cover assembly 420 further includes an inner optical barrier 423 positioned between the annular detection window 422 and each of the plurality of emission windows 424a-424h. In some variations, the cover assembly 420 includes an outer optical barrier 428 that at least partially surrounds (e.g., fully surrounds) the annular detection window 422. Thecover assembly 420 may also include a set of electrodes 425a-425b, such as described in more detail herein.

[0106] The annular detection window 422 is positioned over a light detector array (not shown) and each emission window of the plurality of emission windows 424a- 424h may be positioned over a corresponding set of light emitters of an emitter array (not shown). Accordingly, light emitted by each light emitter of the light emitter array may exit the optical sensing module 400 through a corresponding emission window of the plurality of emission windows 424a-424h (e.g., the emission window that is placed over that light emitter).

[0107] In some variations, the plurality of emission windows 424a-424h may be radially arranged around a portion of the cover assembly 420 (e.g., radially arranged around a center of the cover assembly 420). For example, the plurality of emission windows 424a-424h may be arranged in a circular pattern, such that each of the plurality of emission windows 424a-424h is positioned such that a circle (not shown) may be drawn that intersects each of the plurality of emission windows 424a-424h. In some of these variations, each of the plurality of emission windows 424a-424h is positioned at a common distance from a point on the cover assembly 420 (e.g., the center of the cover assembly 420).

[0108] In some instances, the plurality of emission windows 424a-424h and the annular detection window 422 are concentrically arranged, such that the plurality of emission windows 424a-424h and the annular detection window 422 are centered around a common point. Accordingly, each emission window of the plurality of emission windows 424a-424h may be separated from the annular detection window 422 by a first common distance di. In these instances, the first common distance di represents the shortest distance between each of the plurality of emission windows 424a-424h and the annular detection window 422. While the first common distance di is only labeled in FIG. 4 for emission windows 424b and 424c, it should be appreciated that the remaining emission windows 424a and 424d-424h of the plurality of emission windows 424a-424h may be separated from the annular detection window 422 by the first common distance di.

[0109] In some embodiments, the cover assembly 420 may include one or more additional windows, in addition to the plurality of emission windows 424a-424h, that are surrounded by the annular detection window 422. For example, the cover assembly 420 may include a center window 429 that is positioned within the cover assembly 420 such that the annular detection window 422 surrounds the center window 429. The center window 429 may be positioned such that the plurality of emission windows 424a-424h are radially arranged around the center window 429. In some of these variations, such as when the plurality of emission windows 424a- 424h are arranged in a circular pattern, each of the plurality of emission windows 424a-424h may be separated from the center window 429 by a second common distance c . In these instances, the second common distance cfe represents the shortest distance between each of the plurality of emission windows 424a-424h and the center window 429. While the second common distance cfeis only labeled in FIG. 4 for emission windows 424b and 424c, it should be appreciated that the remaining emission windows 424a and 424d-424h of the plurality of emission windows 424a- 424h may be separated from the center window 429 by the second common distance d2.

[0110] In instances where the cover assembly 420 includes a center window 429, the center window 429 may be positioned over one or more components of the optical sensing module 400. In some instances, the center window 429 may be positioned over one or more light emitters of the light emitter array, such that light emitted from these light emitters may exit the optical sensing module 400 through the center window 429. Additionally or alternatively, the optical sensing module 400 may include a fiducial marker that is positioned below center window 429, such as described herein with respect to FIG. 1 1 D, which may aid in alignment of components of the cover assembly 420.

[0111] In some examples, at least a portion of the center window 429 may be selectively transparent, such that only light of certain wavelengths may pass through the center window 429. For example, at least a portion of the center window 429 may be configured such that it is opaque to light within the visible spectrum and transparent to light at one or more wavelengths in the infrared spectrum. In these instances, the center window 429 may not be readily visible to a user by virtue ofbeing opaque to visible light, but the center window 429 may still pass infrared light. This may allow for a light emitter that is configured to generate light at an infrared wavelength to emit light through the center window 429 and / or may allow for a fiducial marker to be imaged, using infrared light, through the center window 429.

[0112] The plurality of emission windows 424a-424h may be defined in any suitable manner. For example, FIGS. 5A-5C show cross-sectional side views of different variations of optical sensing modules that include the plurality of emission windows 424a-424h. Accordingly, each of these optical sensing modules may represent a cross-section of the optical sensing module 400, taken along line 5A-5A. For example, FIG. 5A shows a first variation of an optical sensing module 500 that includes a cover assembly 520 that includes the plurality of emission windows 424a- 424h (only emission windows 424a and 424e are depicted in FIG. 5A), the annular detection window 422, the inner optical barrier 423 and the outer optical barrier 428 of the cover assembly 420 of FIG. 4. The optical sensing module 500 further includes the light detector array 332, the light emitter array 334, and the substrate assembly 330 described herein with respect to FIGS. 3A and 3B.

[0113] In the variation of the cover assembly 520 shown in FIG. 5A, each of the plurality of emission windows 424a-424h is at least partially defined by different transparent portions of a cover member. In these instances, the different emission windows 424a-424h may be formed from separate portions of a cover member, which may provide additional control in routing light that is emitted by the light emitter array 334. In the example shown in FIG. 5A, the cover assembly 520 may include the cover member 240 of FIGS. 2D-2F. In these instances, each inner transparent portion of the plurality of inner transparent portions 242a-242h may at least partially define a corresponding emission window of the plurality of emission windows 424a- 424h (e.g., a first inner transparent portion 242a may at least partially define a first emission window 424a, a second inner transparent portion 242b may at least partially define a second emission window 424b, and so on). Accordingly, light that exits the optical sensing module 500 through a particular emission window of the cover assembly 520 will pass through the corresponding inner transparent portion of the cover member 240.

[0114] Similarly, the outer transparent portion 204 of the cover member 240 may at least partially define the annular detection window 422, such light that enters the optical sensing module 500 through the annular detection window 422 passes through the outer transparent portion 204 of the cover member 240. In these variations, the inner opaque portion 206 of the cover member 240 may form the inner optical barrier 423 and the outer opaque portion 208 of the cover member 240 may form the outer optical barrier 428.

[0115] The optical sensing module 500 may include a set of emission optical elements that are positioned over the plurality of emission windows 424a-424h. For example, the optical sensing module 500 may include a plurality of emission optical elements 526a-526h (only emission optical elements 526a and 526e are depicted in FIG. 5A) that are positioned in the inner cavity 336 and attached to the interior surface 210 of the cover member 240. Each emission optical element of the plurality of emission optical elements 526a-526h may be positioned over a corresponding emission window of the plurality of emission windows 424a-424h (e.g., a first emission optical element 526a may be positioned over a corresponding first emission window 424a and the corresponding first inner transparent portion 242a of the cover member 240, and so on). In this way, light emitted by a light emitter of the light emitter array 334 may pass through a corresponding emission optical element of the plurality of emission optical elements 526a-526h before passing through the corresponding emission window of the plurality of emission windows 424a-424h.

[0116] Similarly, the optical sensing module 300 may include a detection optical element 327 that is positioned in the outer cavity 337 and attached to an interior surface 210 of the cover member 240. The detection optical element 327 may be positioned over the annular detection window 422, such that light collected through the annular detection window 422 passes through the detection optical element 327 before reaching the light detectors of the light detector array 332.

[0117] Although the cover member 240 is shown in FIG. 5A as not including center transparent portion 260, it should be appreciated that in some examples (such as when the optical sensing module 500 includes the center window 429 of FIG. 4) the cover member 240 may include the center transparent portion 260. In these instances, the center transparent portion 260 may at least partially define acorresponding window (e.g., center window 429) that extends through the cover assembly 520.

[0118] In other variations, multiple of the plurality of emission windows 424a-424e may be at least partially formed by a common inner transparent portion of a cover member. FIG. 5B shows another variation of an optical sensing module 502, which may be configured and labeled the same as the optical sensing module 500 of FIG. 5A except that the cover member 240 has been replaced with the cover member 200 of FIGS. 2A-2C. The optical sensing module 502 may represent a cross-sectional side view of the optical sensing module 400, taken along line 5A-5A, with dashed line 430 in FIG. 4 representing the second interface 216 between the inner opaque portion 206 and the outer transparent portion 204 of the cover member.

[0119] In this example, cover assembly 520 may further include an aperture layer 582 that is attached to an interior surface 210 of the cover member 200 and positioned within the inner cavity 336. Specifically, the aperture layer 582 may be opaque, and may define a plurality of apertures that extend through the aperture layer 582. Each aperture of the aperture layer 582 may at least partially define a corresponding window of the plurality of emission windows 424a-424h. In these instances, each of the plurality of emission windows 424a-424h will be also partially formed from the inner transparent portion 202 of the cover member 200. Accordingly, for light (e.g., light generated by the light emitter array) to exit the optical sensing module 502 through an emission window of the plurality of emission windows 424a- 424h, the light passes through a corresponding aperture of the aperture layer 582 and a portion of the inner transparent portion 202 of the cover member 200.Examples of aperture layers are discussed herein with respect to FIGS. 6-7B. The plurality of emission optical elements 526a-526h may be at least partially positioned within the plurality of apertures. Specifically, each of the plurality of emission optical elements 526a-526h may be positioned at least partially within a corresponding aperture of the aperture layer 582, such as described in more detail herein with respect to FIGS. 6-7B.

[0120] FIG. 5C shows still another variation of an optical sensing module 504, which may be configured and labeled the same as the optical sensing module 502 of FIG. 5B except that the cover assembly 520 includes the center window 429. Inthese variations, the aperture layer 582 may include an additional aperture (referred to herein as a “center aperture”) that may at least partially define the center window 429. In these instances, light that exits the optical sensing module 504 through the center window 429 may pass through the center aperture of the aperture layer 582 and a portion of the inner transparent portion 202 of the cover member 200.

[0121] In some of these variations, a selectively transparent material 584 may be positioned within the center aperture of the aperture layer 582. In these variations, the selectively transparent material 584 may only allow certain wavelengths to pass through the center window 429. For example, selectively transparent material 584 may be configured such that it is opaque to light within the visible spectrum and transparent to light at one or more wavelengths in the infrared spectrum. In these instances, even though light in the visible spectrum may be able to pass through the inner transparent portion 202 of the cover member, it may be blocked by selectively transparent material 584 (and thus is considered to not pass through the center window 429). Infrared light emitted or reflected by a component 586 positioned under the selectively transparent material 584 may exit the optical sensing module 504 through the center window 429.

[0122] In some variations, the aperture layer 582 and the plurality of emission optical elements 526a-526h may be formed as separate components. FIG. 6 shows an exploded perspective view of an arrangement 600 that includes an aperture layer 602 and a plurality of emission optical elements 526a-526h. The aperture layer 602 may, in some examples, be formed from an opaque coating (e.g., an ink coating) that is deposited on an interior surface of a cover member (e.g., the interior surface 210 of the cover member 200 of FIGS. 2A-2C). In other instances, the aperture layer 602 may be formed separately from the cover member, and may be attached to the cover member (e.g., using an adhesive, such as an optically clear adhesive). In examples where the cover member includes an anti-reflective coating (e.g., anti- reflective coating 220 of the cover member 200 of FIGS. 2A-2C) deposited on an interior surface of the cover member, the aperture layer 602 may be connected to the cover member such that the anti-reflective coating is positioned between the aperture layer 602 and the cover member.

[0123] The aperture layer 602 may be patterned or otherwise shaped to define a plurality of apertures 604a-604h that extend through the aperture layer 602. Each aperture of the plurality of apertures 604a-604h may define a portion of the inner surface of the cover member (e.g., a portion of the inner surface 210 of the cover member 200 of FIGS. 2A-2C that corresponds to the inner transparent portion 202) through which light may enter or exit the cover member. Accordingly, each aperture of the plurality of apertures 604a-604h may at least partially define a corresponding emission window of a cover assembly as described herein.

[0124] Accordingly, the layout of the plurality of apertures 604a-604h may at least partially define the corresponding locations of the plurality of emission windows within an optical sensing module. For example, if it is desirable to provide a plurality of emission windows arranged in a circular pattern, the plurality of apertures 604a- 604h may be arranged in a circular pattern. In this way, each of the plurality of apertures 604a-604h may be positioned over a corresponding light emitter or group of light emitters of a light emitter array (e.g. light emitter array 334) as described herein, which may thereby position an emission window over the corresponding light emitter or group of light emitters.

[0125] The plurality of emission optical elements 526a-526h may be formed separately from aperture layer 602. When the arrangement 600 is incorporated into a cover assembly of an optical sensing module as described herein, each of the plurality of emission optical elements 526a-526h may be positioned at least partially within a corresponding aperture of the plurality of apertures 604a-604h (e.g., a first emission optical element 526a is positioned at least partially inside of a first aperture 604a, a second emission optical element 526b is positioned at least partially inside of a second aperture 604b, and so on). In these instances, light passing through a given aperture of the aperture layer 602 will also pass through a corresponding emission optical element of the plurality of optical elements 526a-526h.

[0126] In some variations, the aperture layer 602 may further define an additional aperture 606 that extends through the aperture layer 602. In variations in which an optical sensing module includes an additional window (e.g., center window 429 of the optical sensing module 400 of FIG. 4 or the optical sensing module 504 of FIG. 5C), the additional aperture 606 may at least partially define this window. In someinstances, the additional aperture 606 may be located at a center of the aperture layer 602. Additionally or alternatively, the plurality of apertures 604a-604h may be radially arranged around the additional aperture 606. In some instances, such as described herein with respect to the optical sensing module 504 of FIG. 5C, the additional aperture 606 may be at least partially filled with a partially transparent material 608.

[0127] In other variations, the aperture layer 602 and the plurality of emission optical elements 526a-526h may be formed as part of an integrated optical component. For example, FIG. 7A shows a cross-sectional side view of an integrated optical component 700 that includes an aperture layer 702 and a piece of transparent material 704 that is shaped to form a plurality of emission optical elements 726a-726b. While only two emission optical elements (e.g., a first emission optical element 726a and a second emission optical element 726b) are shown in FIG. 7A, it should be appreciated that the integrated optical component 700 may include a corresponding emission optical element for each emission window of an optical sensing module incorporating the integrated optical component 700.

[0128] The aperture layer 702 may be opaque and may define a plurality of apertures 706a-706b that extend through the aperture layer 702. While only two apertures (e.g., a first aperture 706a and a second aperture 706b) are shown in FIG. 7A, it should be appreciated that the aperture layer 702 may include a corresponding aperture for each emission window of an optical sensing module incorporating the integrated optical component 700. In some variations the aperture layer 702 may be formed from an opaque polymer material that includes an additive, such as a pigment or dye, that provides opacity to the polymer material. In some cases, a color of the aperture layer 702 may be matched to the color of an opaque portion of the overlying cover member. The piece of transparent material 704 may be formed such that the piece of transparent material 704 may extend at least partially through each of the plurality of apertures 706a-706b. The piece of transparent material may be formed from a transparent polymer material.

[0129] The integrated optical component 700 may define a first surface 710 and a second surface 712 that is opposite the first surface 710. In some variations, the piece of transparent material 704 fills each of the plurality of apertures 706a-706bsuch that the piece of transparent material 704 is coplanar with the aperture layer 702 at the second surface 712. In these examples, the second surface 712 may be a flat surface. The piece of transparent material 704 may at least partially define the first surface 710 of the integrated optical component 700, and in some instances the aperture layer 702 may also define a corresponding portion of the first surface 710 of the integrated optical component 700.

[0130] Regions of the piece of transparent material 704 at the first surface 710 may be patterned or otherwise shaped to define the plurality of emission optical elements 706a-706b. For example, in variations where each emission optical element of the plurality of emission optical elements 706a-706b includes an array of micro-optics, such as described herein with respect to FIGS. 14A-16B, each array of micro-optics may be formed in the piece of transparent material 704 at the first surface 710. In some examples, the piece of transparent material 704 may include one or more flat regions 709 at the first surface 710 that connect the different emission optical elements 706a-706b that are formed in the first surface 710.

[0131] In some variations, the integrated optical component may be made using a process that includes an operation of molding the transparent polymer material into the apertures defined in the opaque polymer material. The molding operation may shape the transparent polymer material to define the plurality of emission optical elements 706a-706b. The molding operation may also mold the transparent polymer material against the opaque polymer material to increase adhesion between the transparent and opaque polymer materials. In some cases, the transparent polymer material is epoxy-based material. The epoxy-based material may be curable by exposure to ultraviolet light. In some examples, a previous molding operation forms the apertures in the opaque polymer material and the integrated optical component is a co-molded optical component. Suitable moldable opaque polymer materials include, but are not limited to, opaque epoxy-based materials or other polymer materials that have suitable adhesion to the transparent polymer material. In other examples, an operation such as a cutting (e.g., laser-cutting) or punching operation forms the apertures in a sheet of the opaque polymer material. Additional suitable opaque polymer materials include, but are not limited to, thermoplastic materials such as polyethylene terephthalate (PET). In some embodiments, one or more of thesurfaces of the opaque polymer that define the apertures may define a feature that interlocks with the transparent polymer material to increase adhesion between the opaque and the transparent materials.

[0132] FIG. 7B shows a partial cross-sectional view of a variation of an optical sensing module 701 that may incorporate the integrated optical component 700 of FIG. 7A. Specifically, the optical sensing module 701 may include a cover assembly720 that includes the cover member 200 of FIGS. 2A-2C and the integrated optical component 700. The optical sensing module 701 further includes the light detector array 332, the light emitter array 334, and the substrate assembly 330 described herein with respect to FIGS. 3A and 3B.

[0133] The integrated optical component 700 may be positioned within the inner cavity 336 and attached to the cover member 200 (e.g., attached to the interior surface of the cover member 200). In some examples, the integrated optical component 700 is sized and positioned to cover the inner transparent portion 202 of the cover member 200, such that light exiting the cover assembly 720 through the inner transparent portion 202 will also pass through the integrated optical component 700 through a corresponding aperture of the plurality of apertures 706a-706b. Accordingly, each aperture of the plurality of apertures 706a-706b may at least partially define a corresponding emission window of the cover assembly 720, and may be positioned over a corresponding light emitter or group of light emitters of the light emitter array 334. Similarly, each emission optical element of the plurality of emission optical elements 706a-706b may be positioned over a corresponding light emitter or group of light emitters of the light emitter array 334.

[0134] In variations in which the cover member 200 includes an anti-reflection coating 220 positioned on an interior surface of the cover member 200, the integrated optical component 700 may be attached to the cover member 200 such that the anti-reflective coating 220 is positioned between the integrated optical component 700 and the cover member 200. For example, the integrated optical component 700 may be attached to the cover member 200 using an adhesive layer721 (e.g., formed from an optically clear adhesive). In these examples, the adhesive layer 721 may be positioned between the anti-reflective coating 220 and the integrated optical component 700. In some examples, such as shown in FIG. 7B, theintegrated optical component 700 may be attached to the cover member 200 such that the second surface 712 faces the cover member 200. In these examples, the plurality of emission optical elements 726a-726b may face toward the light emitter array 334 and away from the cover member 200.

[0135] FIG. 8A depicts a cross-sectional view of an example optical sensing module 800, as described herein. The optical sensing module 800 is integrated with a coil assembly 850 that is configured to conduct wireless power transfer between the electronic device and an external or second device, which may be a charging device or accessory. The coil assembly may operate similar to the coil assembly 150 described above with respect to FIG. 1 C. The coil assembly 850 may be configured to receive wireless power produced by an external wireless charging device or accessory. The external wireless charging device or accessory may produce electromagnetic fields as a result of alternating current being passed through a transmitting or charger coil of the charging device or accessory. When coil assembly 850 is positioned within the fields (e.g., when the device is proximate to or contacting the charging device or accessory), a resulting current is produced in the coil assembly 850, which may be used to provide power to the battery or other components of the device. In the present example, the coil assembly 850 is positioned below or inward of the cover member 820 and is configured to receive wireless power through the cover member 820 and electrodes 822. As described previously, the electrodes 822 may be formed from a conductive material and may have a thickness that facilitates transmission of the wireless power without substantially interfering with the power transmission.

[0136] To further facilitate wireless power transmission, the coil assembly 850 may also include a ferritic frame 852, which may define a groove or channel 856 in which a set of coils or coil 860 is positioned at least partially within. While the channel 856 is depicted as having one example shape, in some implementations, the bottom surface of the channel 856 may be angled with respect to a plane of the substrate. For example, the bottom surface of the channel 856 may have an angle or shape that corresponds to a respective portion of the exterior surface of the cover member 820 and / or interior surface of the cover member 820 that is positioned over the coil 860, which may enable the coil to be positioned closer to coils of an externalcharging device or accessory. Generally, the shape and depth of the channel 856 may allow the coil assembly 860 to be positioned substantially adjacent to the respective portion of the interior surface of the cover member 820.

[0137] The ferritic frame 852 may be formed from a ferrite, which may include a magnetic compound of iron-oxide or other ferritic materials. Other example ferritic materials may include magnetite, zinc ferrite, cobalt ferrite, manganese-zinc ferrites, nickel-zinc ferrites, and other similar materials. The ferrite may include a sintered ferrite material that is sintered or molded into the form factor depicted in the current example, or another shape having some or all of the features described herein. The ferritic frame may have a relatively high magnetic permeability. For example, the ferritic frame 852 may have a magnetic permeability that ranges from 1000 to 3000 H / m or from 1000 to as high as 15,000H / m. The ferritic frame 852 may improve the electrical operation of the coil assembly 850 by shunting electrical flux or fields produced by a charging device or accessory and received by the coil(s) 860. The ferritic frame 852 may also improve the effective charging distance and charging efficiency when the coil(s) 860 are operably coupled to the charging device or accessory. The ferritic frame 852 may also help to shield internal components from electrical flux or fields by reducing the strength and / or size of the field that extends inward with respect to the coil(s) 860. As shown in the current example, the ferritic frame 852 includes a groove or channel 856 having an opening that faces the cover member 820. The ferritic frame 852 also includes a set of walls that define the channel 856 and, because they are formed from a ferritic material, may perform the shunting and shielding functionality, described above.

[0138] In this implementation, the ferritic frame 852 also forms part of the optical sensing module. Specifically, the ferritic frame 852 may form at least a portion of an optical barrier of the optical sensing module and may also form a portion of a seal or ingress-inhibiting element for some of the components of the module. In the example of FIG. 8A, the ferritic frame 852 includes an inner flange 854 positioned along the periphery of the optical sensing module and may help to both block stray light from reaching the light detector array 332. The ferrite material of the ferritic frame 852 may be a dark opaque material, which may absorb stray light and also reduce glare or reflection of light received through a translucent portion of the cover member 820.In some cases, an opaque or light absorbing coating may also be applied to the ferritic frame 852 in order to further reduce the presence of stray or reflected light.

[0139] In the example of FIG. 8A, the inner flange 854 may also be positioned between the substrate(s) 331 and the inner surface of the cover member 820 and form a barrier for an ingress of particulate or other contaminates into the optical sensing module. In some instances, a sealing member like a compliant material or an adhesive or sealant is also positioned at least partially around the inner flange 854 or other portion of the ferritic frame 852, which may improve the barrier or seal. The inner flange 854 or other portion of the ferritic frame 852 may also function, in some implementations, as a spacer or standoff between the substrate(s) 331 and the cover member 820. For example, the ferritic frame 852 may provide the substantial or only structural support for the substrate(s) 331 . The ferritic frame 852 may also provide the substantial structural support along with the inner barrier wall 333 or another similar component.

[0140] As mentioned above, the coil assembly 850 is configured to receive wireless power through the cover member 820 and other components attached thereto. In this example the coil assembly 850 receives power that is transmitted from a wireless charging device and through the electrodes 822, which are positioned along an exterior surface of the cover member 820. The electrodes 822 may be formed from a conductive material having a thickness that enables detection of a voltage on the skin of a user, when worn, and also does not substantially interfere with wireless charging operations performed between the coil assembly 850 and the external charging device or accessory. The electrodes 822 may be formed form a conductive metal including stainless steel or other metal alloy. As described previously, the electrodes 822 may also be formed from other conductive coatings including aluminum titanium nitride (AITiN), chromium silicon carbonitride (CrSiCN), or indium titanium oxide (ITO). Other coatings or materials may also form part of the electrodes 822 including aluminum oxide (AI2O3), silicon dioxide (SiOs), silicon nitride (SislSk), and / or diamond-like carbon (DLC).

[0141] In the example of FIG. 8A, the cover member 820 may also have a convex contoured shape that is configured to maintain contact with the user’s skin during a sensing operation. Specifically, the convex shape may help to ensure the devicepresses the cover member 820 against the skin of the user without causing discomfort in order to facilitate reliable sensing operations. The convex shape may also help to align the device with an external charging device or accessory, which may have a corresponding concave contoured shape. Further, in the present example, the convex contoured shape is centered about the center of the device, which may facilitate alignment with the charging device or accessory in a variety of orientations.

[0142] FIG. 8B depicts a simplified exploded view of the coil assembly 850 including the ferritic frame 852 and the coil(s) 860. As shown in this example, the ferritic frame includes a groove or channel 856, which at least partially encloses the coil(s) 860. The groove or channel 856 may define an opening or open-end that faces the rear of the device. As a result, the ferritic material that forms the groove or channel 856 partially surrounding the coil(s) 860 is able to function as a shunt and / or shield for the electromagnetic fields produced as a result of alternating current passed through a charging device or accessory and received by the coil(s) 860 during a charging operation. Acting as a shunt, the ferritic frame 852 may increase the amount of wireless power that is received by the coil (s) 860, which may improve the efficiency or power transfer received by an external charging device or accessory.

[0143] The coil(s) 860 may be formed from a single continuous conductor, which may include a wire or other conductive conduit. The diameter of the wire or conduit and the number of wraps or windings of the coil(s) 860 may be configured to receive a predicted amount of wireless power transmitted by the external charging device or accessory. In some implementations, the coil(s) may include multiple separate wires or conductive conduit that together receive the wireless power transmitted by the charging device or accessory. Each wire may be selectively operated in order to match or pair the coil(s) 860 with a particular charging device of a set of different charging devices having different operating characteristics. The coil(s) 860 may be embedded or encapsulated in a binder or encapsulant that helps to retain the coil(s) 860 within the groove or channel 856. In this example, the ferritic frame 852 defines an opening 858, which may be used to route wires of the coil(s) 860 into and out of the groove or channel 856.

[0144] Similar to previous examples, the optical sensing module 800 of FIG. 8A may include many of the same sensing elements and module components. A complete description of each component is not repeated in order to reduce redundancy. As shown in FIG. 8A, the optical sensing module 800 includes light emitters and light detectors positioned below a cover member. Specifically, a light emitter array 334 is positioned below an inner or central transparent portion 202 of the cover member 820 and a light detector array 332 is positioned below an outer transparent portion 204. Light emitted from the light emitter array 334 is transmitted through one or more optical elements, such as one or more emission windows described herein with respect to other examples. Similarly, the reflected light received by the light detector array 332 is transmitted through one or more detection optical elements 327, also described herein with respect to other examples. The light emitter array 334 and the light detector array 332 are positioned on substrate(s) 331 , which may include additional electronic circuitry that is operable to route and / or process signals from the light emitter array 334 and the light detector array 332. The optical sensing module 800 may include other elements not expressly depicted or described with respect to this example including optical coatings, aperture layers, lenses, and other components described herein with respect to other examples.

[0145] FIGS. 9A-9B depict example optical sensing modules having a cover member with integrated barrier walls. Specifically, FIG. 9A depicts an example optical sensing module having a cover member 920 that includes integrated inner barrier 933 and integrated outer barrier 935 features. Similar to other examples described herein, the inner barrier 933 may partially define an inner cavity in which the light emitter array 334 is positioned. Similarly, the outer barrier 935 and the inner barrier 933 may partially define an outer cavity in which the light detector array 332 is positioned. The inner barrier 933 and the outer barrier 935 may facilitate optical isolation between the inner cavity and outer cavity and inhibit the transmission of light directly between the two cavities. The inner barrier 933 and the outer barrier 935 may also function as a structural standoff or spacer between the rear of the cover member 920 and the substrate(s) 331 . For example, the spacing between a top surface of the substrate(s) 331 and a rear surface of the cover member, including the rear surface of the inner transparent portion 202 and the rear surface of the outer transparent portion 204, may be determined or set by a height or thickness of theinner barrier 933 and the outer barrier 935. In some implementations, the upper surface of the substrate(s) 331 is adhered or otherwise attached to a lower surface of one or both of the inner barrier 933 and the outer barrier 935.

[0146] In this example, the inner barrier 933 and the outer barrier 935 may be formed as part of the same sintering or co-molding process used to form the cover member 920. As described above with respect to FIGS. 2A-2C, a cover member may be formed from two ceramic materials in a co-molding or sintering process that results in a unitary or monolithic piece of ceramic composite that defines the cover member 920. In this example the inner barrier 933 and the outer barrier 935 are formed as part of the inner opaque portion 206 and the outer opaque portion 208. In this example, the inner barrier 933 of the inner opaque portion 206 protrudes with respect to the transparent portions 202 and 204 at the interior surface of the cover member 920 and the outer barrier 935 of the outer opaque portion 208 protrudes with respect to the transparent portion 204 at the interior surface of the cover member 920. As described previously, the opaque portions of the cover member 920 may be formed from a first polycrystalline zirconia material and the transparent portions 202, 204 of the cover member 920 may be formed from a second polycrystalline zirconia material. Each of the first polycrystalline zirconia material and the second polycrystalline zirconia material may be formed at least in part by sintering of fine zirconia crystals. Furthermore, chemical bonding at the interfaces between the first polycrystalline zirconia material and the second polycrystalline zirconia material may be produced at least in part through solid-state diffusion bonding. Therefore, the interface between the first polycrystalline zirconia material and the second polycrystalline zirconia material may be referred to as a diffusion- bonded interface. Since both the materials being bonded are polycrystalline zirconia materials, an interlayer may be omitted, and the diffusion-bonded interface may provide a seamless appearance. The diffusion bonding may be produced using one or more of a sintering operation, a hot-pressing operation, or the like. The coefficient of thermal expansion of the first and the second polycrystalline zirconia material may be sufficiently matched so that the interfaces retain their integrity upon cooling from elevated process temperatures.

[0147] In some variations, the cover member 920 is co-molded from the opaque zirconia material and the transparent zirconia material and may therefore be referred to as a co-molded cover member 920. In some cases, the process for making the cover member 920 includes two ceramic injection molding operations. For example, the process may form a first workpiece from a precursor of the opaque zirconia material at least in part through a first ceramic injection molding operation. The first workpiece may define recesses into which a precursor of the transparent zirconia material is introduced in a second ceramic injection molding operation. A second workpiece is formed by the second injection molding operation, and this second workpiece typically undergoes additional processing operations to form the cover member 920. The second injection molding operation may produce close contact between the precursor of the transparent zirconia material and the material of the first workpiece, which in turn can contribute to formation of a high-quality interface between the opaque and transparent zirconia materials in the finished cover member 920. For example, the process for making the cover member 920 may result in a transparent portion of the cover member being “molded to” an adjacent opaque portion so that it closely conforms to that opaque portion. Additional operations in the process for making the cover may include one or more of a binder removal operation from a precursor of the zirconia material, a sintering operation, a pressure assisted consolidation operation (e.g., hot isostatic pressing), a machining operation, a polishing operation, and coating operation.

[0148] In the present example, the inner barrier 933 and the outer barrier 935 are molded or formed as part of the operations used to form the opaque portions 206, 208. The exterior surfaces of the cover member 920 may be defined by a postmolding or post-sintering machining operation. For example, a grinding or cutting operation may be used to remove material and define the final geometry of the cover member 920. Additional polishing or surface finishing operations may also be performed on the cover member 920. As part of these processes, the geometry of the inner barrier 933 and the outer barrier 935 may be formed and finalized resulting in the geometry depicted in the examples of FIGS. 9A and 9B. Specifically, the inner barrier 933 and the outer barrier 935 may define two concentric rings or flanges that extend from a rear surface of the cover member 920. In some implementations, the inner barrier 933 and the outer barrier 935 have a tapered or drafted side surface tofacilitate the molding process. Example taper or draft angles include 0.5 - 5 degrees, which may be exhibited in side surfaces of the inner barrier 933 and the outer barrier 935 oriented substantially perpendicular or transverse to a parting line of a mold or other tooling used to form the base geometry of the cover member 920.

[0149] FIG. 9B depicts another example optical sensing module having a cover member 922 that includes integrated inner barrier 943 and integrated outer barrier 945 features, which are used in conjunction with separate barrier wall components, inner wall 944 and outer wall 946. Similar to other examples described herein, the inner barrier 943 may partially define an inner cavity in which the light emitter array is positioned. Similarly, the outer barrier 945 and the inner barrier 943 may partially define an outer cavity in which the light detector array is positioned. The inner barrier 943 and the outer barrier 945 may facilitate optical isolation between the inner cavity and outer cavity and inhibit the transmission of light directly between the two cavities. Similar to the previous example, the inner barrier 943 and the outer barrier 945 may also function as a structural standoff or spacer between the rear of the cover member 922 and the substrate(s) 331 . In this example, the inner barrier 943 and the inner wall 944 together define the spacing between a top surface of the substrate(s) 331 and a rear surface of the cover member 922. Similarly, the outer barrier 945 and the outer wall 946 together define the spacing between a top surface of the substrate(s) 331 and a rear surface of the cover member 922. That is, the spacing may be determined or set by a height or thickness of the inner barrier 943 plus the inner wall 944 and also the height or thickness of the outer barrier 945 plus the outer wall 946. In some implementations, the upper surface of the substrate(s) 331 is adhered or otherwise attached to a lower surface of one or both of the inner wall 944 and the outer wall 946.

[0150] Similar to the previous example, the inner barrier 943 and the outer barrier945 may be formed as part of the same sintering or co-molding process used to form the cover member 922. As described above, the cover member 922 may be formed from two ceramic materials in a co-molding or sintering process that results in a unitary or monolithic piece of ceramic composite. The inner wall 944 and outer wall946 may be formed from a variety of materials including ceramic, metal, polymer, or a composite of multiple materials. The inner wall 944 and outer wall 946 may beformed from an opaque material and / or may be coated with an opaque material configured to absorb light. The opaque material and / or the coating may be adapted to absorb light in the frequency emitted by the light emitter array.

[0151] FIG. 10 depicts an example optical sensing module in which the cover member 1020 is formed from multiple transparent members that may be coupled to each other using an adhesive or other bonding element. As shown in the current example, the cover member 1020 is formed from a first, inner member 1024 that defines the inner transparent portion of the cover member 1020 and a second, outer member 1022 that defines the outer transparent portion of the cover member 1020. Similar to other examples described herein, a light emitter array 334 may be positioned below or inward of the inner transparent portion and a light detector array 332 may be positioned below the outer transparent portion. Also similar to previous examples, the light emitter array 334 and the light detector array 332 may be positioned on one or more substrates 331 , which are coupled to a rear of the cover member 1020 by one or more standoffs or barrier walls. The optical sensing module of FIG. 10 may include other elements not expressly depicted or described with respect to this example including optical coatings, aperture layers, lenses, and other components described herein with respect to other examples. A detailed description of these elements is not repeated to reduce redundancy and improve clarity.

[0152] The inner and outer members 1022, 1024 may be formed from a transparent material including a transparent ceramic material, as described herein, the inner and outer members 1022, 1024 may also be formed from other nonceramic materials and may be each formed from a different material. If the inner and outer members 1022, 1024 are formed from different materials, the materials may be formulated or selected to have a coefficient of thermal expansion that is substantially matched or substantially similar.

[0153] In the example of FIG. 10, the inner member 1024 is positioned on a shelf or flange 1023 that is defined by or formed into the outer member 1022. The inner member 1024 may be bonded to the outer member 1022 along the flange 1023 and to an opening of the outer member 1022 by a bonding element 1026, which may include an adhesive or other bonding agent. The bonding element 1026 may, in some cases, include a bonding frit or ceramic material that may be used to bond theinner member 1024 to the outer member 1022 using a sintering or frit-bonding process.

[0154] In the present example, the bonding element 1026 or other element positioned between the inner member 1024 and the outer member 1022 may define an opaque portion of the cover member 1020. The opaque portion may be opaque with respect to the operational wavelengths of the light emitter array 334 or other light emitting elements of the optical sensing module. Similar to the previous examples described, herein, the opaque portion may define a barrier between lightemitting portions of the cover member 1020 (e.g., inner member 1024) and lightreceiving portions of the cover member 1020 (e.g., outer member 1022). In implementations in which the bonding element 1026 is substantially opaque with respect to the operational wavelengths of the optical sensing module, element 1026 may be referred to as a barrier portion. In other implementations, a portion of the layer 1042 or other similar element may extend between the inner member 1024 and the outer member 1022 to define the opaque portion or barrier portion.

[0155] In the present example, the cover member 1020 also includes a first or inner layer 1042 defining light emitter apertures and a second or outer layer 1044 defining one or more light detector apertures. The first and second layers 1042, 1044 may be formed from an opaque material that may be co-molded or co-formed with the transparent material of the inner member 1024 and outer member 1022, respectively. For example, the first and second layers 1042, 1044 may be formed from an opaque ceramic material similar to or the same as materials described with respect to other embodiments, herein. The first and second layers 1042, 1044 may also be formed from other materials including a metal or polymer material that may be formed into or otherwise define a portion of the cover member 1020. In some variations, the optical sensing module may include an inner barrier wall 1033 and an outer water wall 1035 positioned between the second layer 1044 and the substrate(s) 331 .

[0156] The optical sensing modules described herein may be used with any suitable combination of light detector and light emitter arrays. In general, a light detector array as described herein may include a plurality of light detectors, each of which may include a corresponding photodiode that is configured to convert light intoan electrical signal. Specifically, each photodiode has a sensing area that may receive light, and each photodiode may generate the electrical signal based on the amount of light received by the sensing area of the photodiode. Accordingly, each light detector may be operable to measure light incident on the light detector and will generate a corresponding measurement signal that is proportional to the light received by the light detector. During a given optical measurement, such as those described in more detail herein, the optical sensing module may operate some or all of the plurality of light detectors to generate a set of measurement signals for the optical measurement. The set of measurement signals, which may include a single measurement signal or a plurality of measurement signals (depending on how many light detectors are operated to generate the measurement signals and how many light emitters are used to generate light), may be analyzed to determine information about the optical measurement.

[0157] FIG. 11 shows a top view of a portion of an optical sensing module 1100 that includes an example of a light detector array 1132. The light detector array 1132 may be used with any of the optical sensing modules described herein. Specifically, the light detector array 1132 includes a plurality of light detectors 1102a-1102h. The optical sensing module 1100 may also include a cover assembly (not shown), a substrate assembly 1130 that includes a set of substrates (depicted in FIG. 11 A as a single substrate 1131 , though it should be appreciated that the substrate assembly may in some instances include a plurality of substrates), an inner barrier wall 1133, and an outer barrier wall 1135, each of which may be configured in any suitable manner as described herein. The optical sensing module 1100 may define an inner cavity 1 136 and an outer cavity 1137 surrounding the inner cavity 1136.

[0158] Each of the plurality of light detectors 1102a-1102h may be positioned in the outer cavity 1137 and may be mounted to a substrate of the set of substrates (e.g., mounted to substrate 1131 ). The plurality of light detectors 1102a-1102h may be radially arranged within the outer cavity 1137, such that the plurality of light detectors 1102a-1102h encircles the inner barrier wall 1133 and thereby encircles the inner cavity 1136. Each light detector of the plurality of detectors 1102a-1102h is shaped to define a plurality of sides 1101 a-1101 d including an inner side 1101a facing the inner barrier wall 1 133, an outer side 1101 b facing away from the innerbarrier wall 1 133 (e.g., toward the outer barrier wall 1 135), a first lateral side 1 101 c connecting the inner side 1 101 a to the outer side 1101 b, and a second lateral side 1101 d connecting the inner side 1 101 a to the outer side 1101 b. While the plurality of sides 1 101 a-1 101 d is only labeled in FIG. 11 A for light detectors 1 102a-1 102c, it should be appreciated that the remaining light detectors of the plurality of light detectors 1102a-1 102h may be also be configured to include a corresponding plurality of sides 1 101 a-1 101 d. The corresponding plurality of sides 1 101 a-1 101 d for each light detector represents the boundaries of the photodiode of that light detector.

[0159] In some variations, such as shown in FIG. 1 1 A, each light detector of the plurality of light detectors 1 102a-1 102h has a common shape. For example, each light detector of the plurality of light detectors 1 102a-1102h has a trapezoidal shape. In some examples, the plurality of light detectors 1102a-1102h may be configured such that immediately adjacent light detectors of the plurality of light detectors 1102a-1 102h have corresponding lateral sides that are parallel. As used herein, two light detectors of a plurality of light detectors are considered to be immediately adjacent if there are no intervening light detectors within the outer cavity 1 137. Using a first light detector 1102a, a second light detector 1 102b, and a third light detector 1102c as an example, the second light detector 1 102b in FIG. 1 1 A is immediately adjacent to each of the first and third light detectors 1 102a and 1 102c. The first lateral side 1 101 c of the second light detector 1102b (which faces the first light detector 1102a) is parallel to the second lateral side 1 101 d of the first light detector 1102a (which faces the second light detector 1 102b). Similarly, the second lateral side 1 101 d of the second light detector 1 102b (which faces the third light detector 1102c) is parallel to the first lateral side 1 101 c of the third light detector 1 102c (which faces the second light detector 1 102b). By configuring immediately adjacent light detectors to have parallel lateral sides, the plurality of light detectors 1102a-1 102h may increase the overall sensing area provided by the plurality of light detectors 1102a-1 102h.

[0160] For example, FIG. 1 1 B shows the optical sensing module 1 100 of FIG. 1 1 A, depicting the location of an annular detection window 1 122 (depicted with dashed lines in FIG. 1 1 B) over the light detector array 1132. Specifically, the annular detection window 1122 is positioned over a corresponding portion of each of theplurality of light detectors 1102a-1 102h. Specifically, each light detector of the plurality of light detectors 1102a-1 102h has a corresponding sensing area that is at least partially positioned underneath the annular detection window 1122. In the example shown in FIG. 11 B, the sensing area of each light detector includes a central region 1105a positioned underneath the annular detection window 1122, an outer peripheral region 1105b positioned between the central region 1105a and the outer barrier wall 1135, and an inner peripheral region 1105c positioned between the central region 1105a and the inner barrier wall 1133. The inner and outer peripheral regions 1105b, 1105c of the sensing area may be positioned behind corresponding opaque portions of the cover assembly. While the sensing area regions 1105a-1105c are only labeled for the second light detector 1 102b in FIG. 1 1 B, it should be appreciated that the corresponding sensing areas of the remaining light detectors of the plurality of light detectors 1102a-1102h are similarly configured.

[0161] The central region 1105a of the sensing area of each light detector may have an arcuate shape that includes corresponding portions of the first and second lateral sides 1101 c, 1101 d of the light detector. Overall, the annular detection window 1122 is positioned over the central regions of the plurality of light detectors 1102a-1102h and is also positioned over the gaps between the lateral sides of immediately adjacent light detectors of the plurality of light detectors 1102a-1102h. By minimizing the gaps between light detectors of the plurality of light detectors 1102a-1102h, the optical sensing module 1100 may increase the effective sensing area of the light detector array 1 132 that is positioned behind the annular detection window 1122. This may improve the overall collection efficiency of the optical sensing module 1 100. For example, in some examples at least 90% of the annular detection window 1122 is positioned over the sensing areas of the plurality of light detectors 1102a-1102h (e.g., less than 10% of the annular detection window 1122 is positioned over gaps between immediately adjacent light detectors). In some of these variations, at least 95% of the annular detection window 1122 is positioned over the sensing areas of the plurality of light detectors 1102a-1102h.

[0162] Each light detector of the plurality of light detectors 1102a-1 102h may include corresponding electrical connections that are configured to operate the light detector. For example, each light detector of the plurality of light detectors 1102a-1102h may include a corresponding electrode pad (not shown in FIGS. 1 1 A and 11 B) and a set of wirebonds 1103a-1103b. In these instances, the photodiode of the light detector may be positioned on a corresponding electrode pad and a corresponding set of wirebonds 1103a-1103b may be connected to a top surface of the photodiode. Collectively, the electrode pad and the set of wirebonds 1103a- 1103b, may electrically connect the light detector to the optical sensor controller (e.g., via the substrate 1131 ). In some variations, the plurality of light detectors 1102a-1102h may share a common electrode pad, such that the corresponding photodiode of each light detector is positioned on a different corresponding portion of the common electrode pad. For example, in some variations the plurality of light detectors 1102a-1102h may be formed as a segmented photodiode, such that each light detector of the plurality of light detectors 1102a-1102h has a photodiode formed by a respective light sensing region of the segmented photodiode.

[0163] While each of the plurality of light detectors 1102a-1102h is shown in FIG. 11 B as having a set of wirebonds 1103a-1103b that includes two wirebonds (e.g., a first wirebond 1103a and a second wirebond 1103b), it should be appreciated that some or all of the light detectors 1102a-1102h may instead include a corresponding set of wirebonds that includes a single wirebond or three or more wirebonds as may be desired. In some variations, it may be desirable to position each set of wirebonds 1103a-1103b such that the wirebonds connect to the outer peripheral region 1105b of the sensing area of the corresponding light detector. In these instances, the set of wirebonds 1103a-1103b may be positioned behind a corresponding opaque portion of a cover assembly, which may reduce the likelihood that the set of wirebonds is visible to a user through the annular detection window 1122. Additionally, the annular detection window 1122 may be positioned over the light detector array 1132 such that the central regions 1105a of the sensing areas are positioned closer to the inner sides 1101 a of the plurality of light detectors 1102a-1102h. This may reduce the separation distance(s) between the annular detection window 1122 and one or more emission windows of the optical sensing module 1100, which may improve the optical efficiency of the optical sensing module 1 100. Similarly, to the extent that the plurality of light detectors 1102a-1 102h include electrical vias or other structures that may otherwise be visible to a user, these structures may similarly be positioned behind a corresponding opaque portion of the cover assembly.

[0164] The electrode pad may be formed from any suitable electrically conductive material (e.g., a metal such as copper). FIGS. 12A-12C show variations of a light detector that is positioned on an electrode pad, and may each represent a corresponding configuration for the light detectors of the plurality of light detectors 1 102a-1102h of FIGS. 1 1 A and 11 B. For example, FIG. 12A shows a variation of a light detector 1200 that includes a photodiode 1202 that is positioned on an electrode pad 1204. In this variation, the photodiode 1202 includes an inner side 1101 a, an outer side 1101 b, and first and second lateral sides 1 101 c, 1 1 Od, such as described herein with respect to the plurality of light detectors 1102a-1 102h of FIGS. 11 A and 1 1 B. Similarly, the electrode pad 1204 is shaped to define a corresponding plurality of sides 1201 a-1201 d including an inner side 1201 a (which may face an inner barrier wall, such as inner barrier wall 1 133 of FIG. 1 1A), an outer side 1201 b (which may face away from the inner barrier wall and toward an outer barrier wall, such as outer barrier wall 1 135 of FIG. 1 1 A), a first lateral side 1201 c connecting the inner side 1201 a to the outer side 1201 b, and a second lateral side 1201 d connecting the inner side 1201 a to the outer side 1201 b.

[0165] In the variation shown in FIG. 12A, the photodiode 1202 is smaller than the electrode pad 1204, such that the entire photodiode 1202 is positioned on and supported by a corresponding portion of the electrode pad 1204. In other words, a perimeter of the electrode pad 1204 (e.g., as defined by the plurality of sides 1201 a- 1201 d) fully surrounds the perimeter of the photodiode 1202 (e.g., as defined by the plurality of sides 1 101 a-1 101 d). In these variations, an exposed portion of the electrode pad 1204 may extend past each side of the photodiode 1202. This may limit how close the photodiodes of two immediately adjacent light detectors may be positioned. Additionally, depending on the material used to form the electrode pad 1204, the exposed portion of the electrode pad 1204 may reflect light that is incident thereon. For example, exposed portions of the electrode pad 1204 that are positioned beneath the annular detection window 1122 of FIG. 1 1 B may be visible to a user by virtue of light reflecting off of the electrode pad 1204.

[0166] FIG. 12B shows another variation of a light detector 1210 that includes the photodiode 1202 and the electrode pad 1204 of FIG. 12A, except that the photodiode 1202 is larger than the electrode pad 1204. In these variations, theelectrode pad 1204 is fully positioned underneath the photodiode 1202. In other words, a perimeter of the photodiode 1202 (e.g., as defined by the corresponding plurality of sides 1 101 a-1 101 d) fully surrounds the perimeter of the electrode pad 1204 (e.g., as defined by the corresponding plurality of sides 1201 a-1201 d). This may allow the lateral sides 1 101 c, 1 101 d of the photodiode 1202 to be placed closer to immediately adjacent light detectors, and may also reduce reflections that would have otherwise occurred from exposed portions of the electrode pad 1204. Additionally, the electrode pad 1204 may be smaller for a given size of the photodiode 1202, as compared to the light detector of FIG. 12A, which may reduce the parasitic capacitance associated with operation of the light detector 1210. This may allow for improved operation of the light detector 1210 (e.g., faster switching speed between light detectors within a light detector array).

[0167] In these variations, a portion of the photodiode 1202 may include an overhang portion that is not directly mechanically supported by the electrode pad 1204 (e.g., is not resting on a corresponding portion of the electrode pad 1204). In some variations, it may be desirable to balance the mechanical support provided by an electrode pad while still allowing a light detector to be placed closer to other light detectors. For example, FIG. 12C shows another variation of a light detector 1220 that includes photodiode 1202 and the electrode pad 1204 of FIG. 12A, where the photodiode 1202 is larger than the electrode pad 1204 in certain directions but is smaller than the electrode pad 1204 in other directions. Specifically, in the variation shown in FIG. 12C, the inner and outer sides 1201 a, 1201 b of the electrode pad 1204 may extend past the corresponding inner and outer sides 1101 a, 1 101 b of the photodiode 1202. Accordingly, the electrode pad 1204 may include a first exposed portion that extends past the inner side 1 101 a of the photodiode 1202 and a second exposed portion that extends past the outer side 1 101 b of the photodiode 1202. The first and second exposed portions may be positioned underneath corresponding opaque portions of a cover assembly, which may limit their ability to reflect light out of an optical sensing module that incorporates the light detector 1220.

[0168] Conversely, the first and second lateral sides 1 101 c, 1 101 d of the photodiode 1202 may extend past the corresponding first and second lateral sides 1201 c, 1201 d of the electrode pad 1204. Accordingly, the photodiode 1202 mayinclude a first overhang portion that extends past the first lateral side 1201c of the electrode pad 1204. This may allow the first lateral side 1101c of the photodiode 1202 to be positioned closer to a first immediately adjacent light detector. Similarly, the photodiode 1202 may include a second overhang portion that extends past the second lateral side 1201 d of the electrode pad 1204, which may allow the second lateral side 1 101 d of the photodiode 1202 to be positioned closer to a second immediately adjacent light detector.

[0169] In the light detectors described herein, such as the light detectors 1200, 1210, and 1220 of FIGS. 12A-12C, the photodiode of the light detector may be connected to the electrode pad in any suitable manner. For example, in some variations the light detectors described herein may include a conductive die attach film (CDAF) that mechanically and electrically connects the photodiode to the electrode pad. For example, FIG. 12D shows a cross-sectional side view of a variation of the light detector 1210 of FIG. 12B, taken along line 12D-12D, which may represent a corresponding configuration for the light detectors of the plurality of light detectors 1102a-1102h of FIGS. 11 A and 11 B. Specifically, in the variation shown in FIG. 12D, the light detector 1210 includes a CDAF 1212 that is positioned between the photodiode 1202 and the electrode pad 1204. The CDAF 1212 may bond the photodiode 1202 to the electrode pad 1204, such that the CDAF 1212 holds the photodiode 1202 in place relative to the electrode pad 1204. Additionally, the CDAF 1212 is electrically conductive such that the CDAF 1212 electrically connects the photodiode 1202 to the electrode pad 1204. In the variation shown in FIG. 12D, the light detector 1210 is mounted to the substrate 1131 (e.g., of the optical sensing module 1100 of FIG. 11 A) as described in more detail herein.

[0170] Because the CDAF 1212 may be pre-formed before assembly of the light detector 1210, the CDAF 1212 may be formed with a predetermined size and shape, and thus the CDAF 1212 may be configured with any size and shape relative to the photodiode 1202 and the electrode pad 1204. For example, in variations of light detectors, such as light detector 1210, where the electrode pad 1204 is positioned fully underneath the photodiode 1202, the CDAF 1212 may also be positioned fully underneath the photodiode 1202. In some variations, the CDAF 1212 may be configured to have the same size and shape as the electrode pad 1204. In theseinstances, the perimeter of the electrode pad 1204 (e.g., as defined by the corresponding plurality of sides 1201a-1201d) shown in FIG. 12B may also represent the perimeter of the CDAF 1212. Accordingly, the overhang portion (labeled 1203 in FIG. 12E) of the photodiode 1202 that is not mechanically supported by the electrode pad 1204 is also not mechanically supported by the CDAF 1212.

[0171] In other variations, the CDAF 1212 may be configured to have a different size than the electrode pad 1204. For example, FIG. 12E shows a top view of a variation of a light detector 1230 that includes the photodiode 1202, the electrode pad 1204, and the CDAF 1212 of FIG. 12D, except that the CDAF 1212 is smaller than the photodiode 1202 and larger than the electrode pad 1204. FIG. 12F shows a cross-sectional side view of the light detector 1230 of FIG. 12E, taken along line 12F-12F. The CDAF 1212 is shaped to define a corresponding plurality of sides 121 1 a-121 1d that define a perimeter of the CDAF 1212. Specifically, the plurality of sides 121 1 a-121 1 d include an inner side 121 1 a (which may face an inner barrier wall, such as inner barrier wall 1 133 of FIG. 11 A), an outer side 121 1 b (which may face away from the inner barrier wall and toward an outer barrier wall, such as outer barrier wall 1 135 of FIG. 1 1 A), a first lateral side 1211 c connecting the inner side 121 1 a to the outer side 1211 b, and a second lateral side 121 1 d connecting the inner side 1211 a to the outer side 121 1 b.

[0172] In these instances, the perimeter of the photodiode 1202 (e.g., as defined by the corresponding plurality of sides 1101 a-1 101 d) fully surrounds the perimeter of the CDAF 1212. The perimeter of the CDAF in turn fully surrounds the perimeter of the electrode pad 1204 (e.g., as defined by the corresponding plurality of sides 1201 a-1201 d). In these variations, a portion of the photodiode 1202 may include an overhang portion 1203 that is not directly mechanically supported by the electrode pad 1204 (e.g., is not resting on a corresponding portion of the electrode pad 1204). The overhang portion 1203 may include a first region 1203a that is not directly supported by either the electrode pad 1204 or the CDAF 1212 and a second region 1203b that is directly supported by the CDAF 1212 but is not directly supported by the electrode pad 1204. Accordingly, in the second region 1203b of the overhang portion 1203, the CDAF 1212 is not directly supported by the electrode pad 1204. Configuring the CDAF 1212 to have an intermediate size between that of theelectrode pad 1204 and photodiode 1202 may allow for reduction of the size of the electrode pad 1204 while still providing mechanical support to part of the overhang portion 1203 of the photodiode 1202.

[0173] FIG. 12G shows a top view of another variation of a light detector 1240 that includes the photodiode 1202, the electrode pad 1204, and the CDAF 1212 of FIG. 12D, except that the photodiode 1202 and the electrode pad 1204 are configured as described herein with respect to the light detector 1220 of FIG. 12C. Accordingly, the photodiode 1202 and the electrode pad 1204 are configured such that the photodiode 1202 is larger than the electrode pad 1204 in certain directions but is smaller than the electrode pad 1204 in other directions. In some of these variations, such as shown in FIG. 12G, the CDAF 1212 may be configured to have a size and shape that corresponds to the overlapping regions of the photodiode 1202 and the electrode pad 1204.

[0174] Specifically, the inner side 1211 a of the CDAF 1212 may be aligned with the inner side 1101 a of the photodiode 1202 and may have a length that corresponds to the portion of the inner side 1101 a of the photodiode 1202 that overlaps the electrode pad 1204. Similarly, the outer side 1211 b of the CDAF 1212 may be aligned with the outer side 1101 b of the photodiode 1202 and may have a length that corresponds to the portion of the outer side 1101 b of the photodiode 1202 that overlaps the electrode pad 1204. Conversely, the first lateral side 121 1c of the CDAF 1212 may be aligned with the first lateral side 1201c of the electrode pad 1204 and may have a length that corresponds to the portion of the first lateral side 1201 c of the electrode pad 1204 that overlaps the photodiode 1202. The second lateral side 1211 d of the CDAF 1212 may be aligned with the second lateral side 1201 d of the electrode pad 1204 and may have a length that corresponds to the portion of the second lateral side 1201 d of the electrode pad 1204 that overlaps the photodiode 1202.

[0175] In other variations, the first lateral side 1211 c of the CDAF 1212 may be laterally positioned between the first lateral side 1201c of the electrode pad 1204 and the first lateral side 1101 c of the photodiode 1202. In these instances, the first overhang portion may be divided into a corresponding first region (in which the photodiode 1202 is not directly supported by either the electrode pad 1204 or theCDAF 1212) and a corresponding second region (in which the photodiode 1202 is directly supported by the CDAF 1212 but is not directly supported by the electrode pad 1204), such as described herein with respect to FIGS. 12E and 12F. Similarly, the second lateral side 121 1 d of the CDAF 1212 may be laterally positioned between the second lateral side 1201 d of the electrode pad 1204 and the second lateral side 1101 d of the photodiode 1202. In these instances, the second overhang portion may be divided into a corresponding first region (in which the photodiode 1202 is not directly supported by either the electrode pad 1204 or the CDAF 1212) and a second region (in which the photodiode 1202 is directly supported by the CDAF 1212 but is not directly supported by the electrode pad 1204), such as described herein with respect to FIGS. 12E and 12F. Additionally or alternatively, the inner side 121 1 a or the outer side 121 1 b of the CDAF 1212 may be positioned between the respective inner sides or outer sides of the photodiode 1202 and the electrode pad 1204. In these instances, one or more portions of the CDAF 1212 may not be covered by the photodiode 1202.

[0176] In still other variations, a dispensed conductive adhesive may be used to mechanically and electrically connect the photodiode to the electrode pad of a light detector. For example, FIGS. 20A and 20B show a top view and a cross-sectional side view taken along line 20B-20B, respectively, of a variation of an optical sensing module 2000 as described herein. The optical sensing module 2000 is configured and labeled the same as the optical sensing module 1100 of FIG. 1 1 A, except that each light detector of the plurality of light detectors 1102a-1 102h includes a corresponding conductive adhesive 2002 that mechanically and electrically connects a photodiode 1202 of the light detector to an electrode pad 1204 of the light detector.

[0177] In the variation shown in FIGS. 20A and 20B, during assembly of the light detector array 1132, a corresponding conductive adhesive 2002 may be dispensed (e.g., as a liquid, gel, paste, or the like) onto the corresponding electrode pad 1204 of each light detector, such that each conductive adhesive 2002 is positioned between the electrode pad 1204 and the photodiode 1202 of a corresponding light detector. For example, the conductive adhesive 2002 is electrically conductive and may include a conductive metal paste (e.g., silver paste, gold paste, or the like), a conductive epoxy, or the like. The conductive adhesives 2002 may be subsequentlycured to bond the corresponding photodiode 1202 to the corresponding electrode pad 1204 for each light detector of the plurality of light detectors 1 102a-1 102h.

[0178] When a light detector is configured to include a photodiode 1202 having one or more overhang portions, such as described herein with respect to the light detectors 1210 and 1220 of FIGS 12B and 12C, it may be desirable to similarly position the conductive adhesive 2002 to be entirely underneath the photodiode 1202. In practice, however, it may be possible that variations that occur when dispensing the conductive adhesive 2002 may cause a portion of the conductive adhesive 2002 to flow past one or more sides of the photodiode 1202. For example, FIG. 20B shows an overflow portion 2004 of the conductive adhesive 2002 that extends past a lateral side of the second light detector 1102b of the light detector array 1132. When this overflow portion 2004 is positioned under the annular detection window 1122, the conductive adhesive may undesirably reflect light out of the annular detection window 1122.

[0179] Accordingly, some variations of the optical sensing module 2000 may include a non-conductive (e.g., not electrically conductive), opaque epoxy 2008 that is positioned between immediately adjacent light detectors of the plurality of light detectors 1102a-1102h. The opaque epoxy 2008 may be dispensed after dispensing the conductive adhesive 2002 for each light detector of the light detector array 1132, which may allow the opaque epoxy to cover any overflow portions (e.g., overflow portion 2004) of the conductive adhesives 2002. The opaque epoxy 2008 may be a colored epoxy (e.g., a black epoxy or the like) that is opaque to light in at least the visible spectrum, and thus the opaque epoxy 2008 may reduce light that would otherwise be reflected of overflow portions of the conductive adhesives 2002. Additionally, the opaque epoxy 2008 may act to provide further mechanical support to the corresponding photodiodes 1202 of the plurality of light detectors 1102a- 1102h, which may reduce the likelihood that a photodiode 1202 of a given light detector delaminates from the corresponding electrode pad 1204.

[0180] In some variations, the optical sensing module 2000 includes a plurality of epoxy regions 2008a-2008h formed from the opaque epoxy, where each epoxy region of the plurality of epoxy regions 2008a-2008h is positioned between a corresponding pair of immediately adjacent light detectors of the plurality of lightdetectors 1102a-1102h. For example, a first epoxy region 2008a may be positioned between and in contact with the first light detector 1102a and the second light detector 1102b, a second epoxy region 2008b may be positioned between and in contact with the second light detector 1102b and the third light detector 1 102c, and so on. Because the opaque epoxy 2008 is not electrically conductive, it may contact multiple photodiodes 1202 while still maintaining electrical isolation between these photodiodes 1202.

[0181] Each epoxy region of the plurality of epoxy regions 2008a-2008h is positioned at least partially beneath the annular detection window 1 122, and thus may provide improved optical uniformity to regions of the optical sensing module 2000 that are positioned under the annular detection region. The plurality of epoxy regions 2008a-2008h may represent discrete epoxy segments (e.g., the first epoxy region 2008a is separate from the second epoxy region 2008b, the second epoxy region 2008b is separate from a third epoxy region 2008c, and so on). Alternatively, some or all of the plurality of epoxy regions 2008a-2008h may represent different portions of a contiguous segment of the opaque epoxy 2008. For example, a portion of the opaque epoxy 2008 may extend along the inner and / or outer sides of the photodiode 1202 of the second light detector 1 102b to connect the first epoxy region 2008a to the second epoxy region 2008b (and thereby form a contiguous segment of the opaque epoxy).

[0182] In some variations, the substrate 1131 includes a plurality of raised dams extending from a top surface of the substrate 1131 , each positioned at least partially between a corresponding pair of immediately adjacent light detectors of the plurality of light detectors 1 102a-1102h. For example, a raised dam 2006 is shown in FIG. 20B as positioned between the first light detector 1102a and the second light detector 1102b. The optical sensing module 2000 may include an additional dam between the second light detector 1102b and the third light detector 1 102c, and so on. Each raised dam 2006 may help to reduce the likelihood that an overflow portion of the conductive adhesive 2002 of one light detector (e.g., the first light detector 1202a) contacts the conductive adhesive 2002 of another light detector (e.g., the second light detector 1202b), which may unintentionally electrically couple the light detectors to each other. Accordingly, the raised dam 2006 may limit how far anoverflow portion of the conductive adhesive of a light detector may travel in a direction toward an immediately adjacent light detector.

[0183] While the light detectors 1 102a-1 102h of FIGS. 1 1 A-11 D and 20A-20B, as well as the light detectors 1200, 1210, 1220, 1230, and 1240 of FIGS. 12A-12G, are shown as each having a trapezoidal shape, it should be appreciated that in other variations, these light detectors may have other shapes if so desired. For example, FIG. 13 shows a top view of a variation of an optical sensing module 1300, which is configured and labeled the same as the optical sensing module 1 100 of FIG. 11 B, except that the plurality of light detectors 1 102a-1 102h have been replaced by a plurality of light detectors 1302a-1302h, each of which has an arcuate shape. Specifically, each of the plurality of light detectors 1302a-1302h includes a plurality of sides 1301 a-1301 d that includes an inner side 1301 a facing the inner barrier wall 1133, an outer side 1301 b facing away from the inner barrier wall 1 133 (e.g., toward the outer barrier wall 1135), a first lateral side 1301 c connecting the inner side 1301 a to the outer side 1301 b, and a second lateral side 1301 d connecting the inner side 1301 a to the outer side 1301 b. In these variations, the inner side 1301 a and the outer side 1301 b are each curved. In some examples, the inner and outer sides 1301 a, 1301 b are formed by equidistant curves, which in some examples may be semi-circular curves.

[0184] The light emitter arrays of the optical sensing modules described herein may include a plurality of light emitters, each of which is operable to emit light. During a given optical measurement, such as those described in more detail herein, the optical sensing module may operate some or all of the plurality of light emitters to emit light. Indeed, at any given point in time during an optical measurement, one or more light emitters of the light emitter array may be operated to emit light from the optical sensing module, and one or more light detectors of the light detector array may be concurrently operated to measure light that is returned to the optical sensing module. Over the course of an optical measurement, an optical sensing module may emit light from different light emitters (or groups of light emitters) in a time- multiplexed manner. For example, in instances where an optical sensing module is used to perform a blood oxygen saturation measurement, the optical sensing module may switch between emitting light at a first wavelength and emitting light at a secondwavelength. Measurement signals associated with the different wavelengths may be compared (e.g., using a ratio of light absorbed at the first wavelength relative to light absorbed at the second wavelength) to measure the blood oxygen saturation of a user.

[0185] Each light emitter of the light emitter array may be operable to emit light at a corresponding wavelength. In some examples, a light emitter array may include multiple sets of light emitters configured to emit different wavelengths of light. For example, a light emitter array may include a set of first light emitters (e.g., one or more first light emitters), where each of the first light emitters is configured to emit light at a first wavelength. The light emitter array may also include a set of second light emitters (e.g., one or more second light emitters), where each of the second light emitters is configured to emit light at a second wavelength. In some examples, the light emitter array may also include a set of third light emitters (e.g., one or more third light emitters), where each of the third light emitters is configured to emit light at a third wavelength. In one example, the first wavelength is a green wavelength (e.g., a wavelength between 495 and 570 nanometers, such as 525 nanometers), the second wavelength is an infrared wavelength (e.g., a wavelength between 780 and 1400 nanometers, such as 850 nanometers), and the third wavelength is a red wavelength (e.g., a wavelength between 620 and 750 nanometers, such as 660 nanometers). The wavelength range for each of the green, the infrared, and the red wavelengths may alternately be referred to as a range of green wavelengths, a range of infrared wavelengths, and a range of red wavelengths, respectively.

[0186] Each light emitter of a light emitter array may be any suitable light source capable of generating and emitting light. Each light emitter includes an emission surface from which light is emitted when the light emitter is operated to generate light. In some examples, the light emitter array includes a plurality of light emitters, where each light emitter is a light-emitting diode (LED). For example, in some variations where the plurality of light emitters includes sets of first, second, and third light emitters configured to emit respective first, second, and third wavelengths, each of the light emitters of the sets of first, second, and third light emitters may be an LED (e.g., the set of first light emitters includes a set of first LEDs configured to generate the first wavelength of light, the set of second light emitters includes a setof second LEDs configured to generate the second wavelength of light, and the set of third light emitters includes a set of third LEDs configured to generate the third wavelength of light). In some examples, one or more light emitters of a light emitter array may be a laser, such as a vertical cavity surface emitting laser (VCSEL).

[0187] In some variations, a light emitter array of the optical sensing modules described herein may include a plurality of light emitters where the light emitters are radially arranged within an inner cavity of the optical sensing module. For example, the optical sensing module 1 100 of FIG. 11 A includes a light emitter array 1134 that includes a plurality of light emitters that is radially arranged within the inner cavity 1136. Specifically, the plurality of light emitters may be arranged in a circular pattern, such that the light emitters (or groups thereof) are positioned around a circle (e.g., a circle that is centered within the inner cavity 1136). Accordingly, the plurality of light detectors of the light detector array 1132 and the plurality of light emitters of the light emitter array 1134 may be concentrically arranged (e.g., the light detectors and the light emitters are radially arranged around a common point, such as the center of inner cavity 1136).

[0188] In the example shown in FIG. 11 A, the plurality of light emitters includes multiple different sets of light emitters, each of which include multiple light emitters configured to emit a corresponding wavelength of light. Specifically, the plurality of light emitters includes a plurality of first light emitters 1104a-1104d, a plurality of second light emitters 1108a-1108d, and a plurality of third light emitters 1 110a- 1110d, each of which is positioned in the inner cavity 1136 and mounted to a corresponding substrate of the set of substrates 1131 (which may the same as or different from the substrate to which the light detectors of the light detector array 1132 are mounted). Each of the first light emitters 1 104a-1104d is operable to emit a first wavelength of light, each of the second light emitters 1108a-1 108d is operable to emit a second wavelength of light, and each of the third light emitters 1 110a-1110d is operable to emit a third wavelength of light. In some examples, the first wavelength is a green wavelength (e.g., 525 nanometers), the second wavelength is an infrared wavelength (e.g., 850 nanometers), and the third wavelength is a red wavelength (e.g., 660 nanometers).

[0189] The plurality of light emitters may be radially arranged such that the light emitters alternate between light emitters of the plurality of first light emitters 1104a- 1104d and light emitter groups of a plurality of light emitter groups 1106a-1106d, each of which includes a corresponding second light emitter of the plurality of second light emitters 1 108a-1108d and a corresponding third light emitter of the plurality of third light emitters 1110a-1 110d. For example, light emitter group 1106b (including second light emitter 1108b and third light emitter 1 110b) may be positioned between first light emitter 1104a and second light emitter 1104b, first light emitter 1104a may be positioned between light emitter group 1106a and light emitter group 1106b (including second light emitter 1108b and third light emitter 1110b), and so on. Only the individual light emitters of light emitter group 1106b are labeled in FIG. 11 B for ease of visibility.

[0190] In some instances, the light emitters of the light emitter array 1134 may be positioned under a common emission window. For example, the optical sensing module 1100 may include a cover assembly that defines an annular detection window 1122 and a single emission window, such as described herein with respect to FIGS. 3A and 3B. In these instances, light emitted by any of the plurality of first light emitters 1 104a-1104d, the plurality of second light emitters 1 108a-1 108d, and the plurality of third light emitters 1110a- 11 10d may exit the optical sensing module through the same emission window.

[0191] In other variations, different light emitters / light emitter groups of the light emitter array 1134 may be positioned under different emission window. For example, FIG. 11 B shows the locations of a plurality of emission windows 1124a-1124h (depicted with dashed lines in FIG. 11 B). The plurality of emission windows 1124a- 1124h may include a first subset of emission windows 1124b, 1124d, 1124f, 1124h, each of which is positioned over a corresponding light emitter of the plurality of first light emitters 1 104a-1104d. For example, first light emitter 1104a is positioned under emission window 1124b, first light emitter 1104b is positioned under emission window 1124d, and so on. Accordingly, light emitted by each first emitter may exit the optical sensing module 1 100 through a corresponding emission window of the first subset of emission windows 1124b, 1124d, 1124f, 1124h.

[0192] The plurality of emission windows 1 124a-1124h may also include a second subset of emission windows 1124a, 1124c, 1124e, 1124g, each of which is positioned over a corresponding light emitter group of the plurality of light emitter groups 1106a-1106d. For example, light emitter group 1106a is positioned under emission window 1124a, light emitter group 1106b is positioned under emission window 1124c, and so on. Accordingly, each emission window of the second subset of emission windows 1124a, 1124c, 1124e, 1124g is positioned over both i) a corresponding second emitter of the plurality of second emitters 1108a-1108d and ii) a corresponding third emitter of the plurality of third emitters 1 110a-1110d.Accordingly, light emitted by a light emitter of the plurality of second emitters 1 108a- 1108d or the plurality of third emitters 1110a-11 10d may exit the optical sensing module 1100 through a corresponding emission window of the second subset of emission windows 1124a, 1124c, 1124e, 1124g. The plurality of emission windows 1124a-1124h may be radially arranged such that the first subset of emission windows 1124b, 1124d, 1124f, 1124h and the second subset of emission windows 1124a, 1124c, 1124e, 1 124g alternate. In these instance, each emission window of the first subset of emission windows 1124b, 1124d, 1124f, 1124h is positioned between a corresponding pair of emissions windows of the second subset of emission windows 1124a, 1124c, 1124e, 1124g, and each emission window of the second subset of emission windows 1 124a, 1124c, 1 124e, 1124g is positioned between a corresponding pair of emissions windows of the first subset of emission windows 1124b, 1124d, 1124f, 1124h.

[0193] Positioning the first light emitters 1104a-1104d under different emission windows than the light emitter groups 1106a-1106d may allow for the optical sensing module 1100 to set different design parameters for different light emitters of the light emitter array 1134. For example, in instances where the plurality of first light emitters 1104a-1104d is configured to emit light at a green wavelength, operation of the first light emitters 1 104a-1104d may be associated with relatively high power consumption. Accordingly, in some instances it may be desirable to increase the relative size of the first light emitters 1 104a-1104d (e.g., the size of the emission surfaces of the first light emitters 1104a-1104d). Increasing the size of the first light emitters 1104a-1104d may improve the efficiency of these emitters by increasing the amount of light generated for a given input current.

[0194] For example, in some variations, each first light emitter of the plurality of first light emitters 1104a-1104d is larger than each light emitter of the plurality of second light emitters 1108a-1108b and is larger than each light emitter of the plurality of the third light emitters 1110a- 11 10b. In some of these variations, each first light emitter of the plurality of first light emitters 1 104a-1104d is larger than the combined size of each light emitter group of the plurality of light emitter groups 1106a-1106b. In other words, the emission surface of a first light emitter (e.g. first light emitter 1104a) is larger than a total area of the corresponding emission surfaces of a second light emitter and a third light emitter of a given light emitter group (e.g., the second light emitter 1108a and the third light emitter 11 10a of the light emitter group 1 106a).

[0195] While it may be desirable to increase the relative size of the plurality of first light emitters 1104a-1104d, it may also be desirable to reduce the distance between the light emitters of the light emitter groups 1106a-1106d. For example, a light emitter group of the plurality of light emitter groups 1106a-1106d may be operated to emit light as part of a blood oxygen saturation measurement. Using light emitter group 1 106a as an example, the second light emitter 1108a may emit light at the second wavelength (e.g., an infrared wavelength) and the third light emitter 110a may emit light at the third wavelength (e.g., a red wavelength) in a time-multiplexed manner. Measurements corresponding to the second and third wavelengths, as measured from the light detector array 1132, may be compared in determining a user’s blood oxygen saturation. To help improve the accuracy of these measurements, it may be desirable for the light emitted by the second light emitter 1108a and the third light emitter 1 110a to pass through the same tissue.

[0196] In practice, light emitted by the second light emitter 1 108a and the third light emitter 11 10a may have different spatial intensity profiles as it exits the optical sensing module 1 100 (e.g., through the emission window 1124a). Reducing the distance from the second light emitter 1108a and the third light emitter 1110a may reduce these spatial intensity differences and may more closely approximate a single light emitter. Accordingly, in some variations the second emitter and third emitter corresponding to each light emitter group of the light emitter groups 1106a-1106d may be mounted to a common electrode pad. In these variations, the optical sensingmodule 1100 includes a plurality of electrode pads 1112a-1112d corresponding to the emitter groups 1106a-1 106d, such that the second light emitter 1108a and the third light emitter 1110a of the emitter group 1106a are mounted to a first corresponding electrode pad 1112a, the second light emitter 1108b and the third light emitter 11 10b of the emitter group 1106b are mounted to a second corresponding electrode pad 1112b, and so on. Each common electrode pad may provide an electrical connection to each of the light emitters mounted thereon, and may allow for closer spacing between these light emitters.

[0197] The light emitters of the light emitter array 1 134 may have any suitable orientation relative to the light detectors of the light detector array 1132. For example, in the variation shown in FIGS. 11 A and 11 B, each of the first light emitters 1104a-1104d and the light emitter groups 1106a-1106d may be positioned in proximity to a different corresponding “closest pair” of light detectors of the plurality of light detectors 1102a-1102h. The closest pair of light detectors for a given light emitter or light emitter group refers to the two light detectors of the plurality of light detectors 1102a-1102h that are positioned closest to that light emitter or light emitter group. For example, in FIGS. 11 A and 11 B, first light emitter 1104a has a corresponding closest pair of light detectors that includes a first light detectors 1102a and a second light detector 1102b, light emitter group 1106b has a corresponding closest pair of light detectors that includes the second light detector 1102b and a third light detector 1102c, first light emitter 1104b has a corresponding closest pair of light detectors that includes the third light detector 1102c and a fourth light detector 1102d, light emitter group 1106c has a corresponding closest pair of light detectors that includes the fourth light detector 1102d and a fifth light detector 1 102e, and so on.

[0198] In some variations, each first light emitter of the plurality of first light emitters 1104a-1104d is positioned to be equidistant to its corresponding closest pair of light detectors. For example, the first light emitter 1104a is equidistant to the first light detector 1102a and the second light detector 1102b, the first light emitter 1104b is equidistant to the third light detector 1102c and the fourth light detector 1102d, and so on. In some of these instances, each first light emitter of the plurality of first light emitters 1104a-1104d is equidistantly spaced from its corresponding closest pair oflight detectors by a common separation distance. In these examples, the first light emitter 1104a is separated from each of the first light detector 1 102a and the second light detector 1 102b by the common separation distance, the first light emitter 1104b is separated from each of the light detector 1102c and the fourth light detector 1102d by the common separation distance, as so on.

[0199] Additionally, each first light emitter of the plurality of first light emitters 1104a-1104d may positioned to be equidistant to one or more additional pairs of light detectors of the plurality of light detectors 1 102a-1102h. Using the first light emitter 1104a as an example, the first light emitter 1104a is positioned equidistant to the first light detector 1102a and the second light detector 1102b (e.g., at a first separation distance from each of the light detectors 1102a, 1102b), is positioned equidistant to the third light detector 1102c and an eighth light detector 1102h (e.g., at a second separation distance from each of the light detectors 1102c, 1102h), is positioned equidistant to the fourth light detector 1102d and a seventh light detector 1102g (e.g., at a third separation distance from each of the light detectors 1102d, 1102g), and is positioned equidistant to a fifth light detector 1102e and a sixth light detector 1102f (e.g., at a fourth separation distance from each of the light detectors 1102e, 1102f). In this way, the plurality of light detectors 1102a-1102h is symmetrically arranged around each first light emitter of the plurality of first light emitters 1104a- 1104d.

[0200] In some examples, the plurality of light emitter groups 1106a-1106d may be configured such that the corresponding second light emitter and third light emitter of each light emitter group are each equidistant to its closest pair of light detectors. Using light emitter group 1106b as an example, the corresponding second emitter 1108b may be positioned to be equidistant to the second light detector 1102b and the third light detector 1102c. Similarly, the corresponding third light emitter 1110c may be positioned to be equidistant to the second light detector 1102b and the third light detector 1 102c. In the variation shown in FIGS. 11 A and 11 B, the second light detector of each light detector group is positioned closer to its corresponding closest pair of light detectors as compared to the third light detector. Again using light emitter group 1 106b as an example, the second light emitter 1108b may be separated from each of the second and third light detectors 1102b, 1102c by a correspondingseparation distance that is less than a corresponding separation distance that separates the third light emitter 1110bfrom each of the second and third light detectors 1102b, 1102c. Accordingly, when the second light emitters 1108a-1108d are configured to emit infrared light and the third light emitters 1 110a-1 110d are configured to emit red light, this may allow the infrared light emitters to be positioned closer to the detection window 1122 as compared to the red light emitters. It should be appreciated that the relative positions of the emitters may be reversed, such that the red light emitters are positioned relatively closer to the detection window 1122 as compared to the infrared light emitters.

[0201] It should be appreciated that the corresponding light emitters of the light emitter groups 1106a-1 106d may have any suitable relative orientation relative to the corresponding closest pair of light detectors. For example, FIG. 110 shows another variation of an optical sensing module 1150, which may be configured the same as the optical sensing module 1 100 of FIG. 11 B except that the light emitters of each of the light emitter groups 1106a-1106d have been rotated by 90 degrees. In these variations, each emitter of a given light emitter group is positioned slightly closer to one of the corresponding closest pair of light emitters. Using the second light emitter 1108b and the third light emitter 1 110b of the light emitter group 1106b as an example, the second light emitter 1108b is positioned closer to the second light detector 1102b than it is to the third light detector 1102c. Conversely, the third light emitter 1110b is positioned closer to the third light detector 1102c than it is to the second light detector 1102b. In some of these variations, the second light emitter 1108b is positioned at a first distance to the second light detector 1102b and the third light emitter 1110b is positioned at the same first distance to the third light detector 1102c. Similarly, the second light emitter 1108b is positioned at a second distance to the third light detector 1102c and the third light emitter 1110b is positioned at the same second distance to the second light detector 1102b, where the second distance is greater than the first distance. The corresponding second and third light emitters of the other light emitter groups may be similarly spaced relative to their corresponding closest light detector pairs.

[0202] FIG. 11 D shows another variation of an optical sensing module 1160 as described herein. The optical sensing module 1160 is configured and labeled thesame as the optical sensing module 1 100 of FIGS. 11 A and 1 1 B, except that the optical sensing module 1160 includes a center window 1129, which may be configured in any manner as described herein with respect to the center window 429 of FIG. 4. The center window 1129 may be positioned such that the plurality of emission windows 1124a-1 124h are radially arranged around the center window 1129. In some variations, the center window 1129 may be selectively transparent, such that it is opaque to light within the visible spectrum and transparent to light at one or more wavelengths in the infrared spectrum.

[0203] In some of these variations, the light emitter array 1 134 may further include, in addition to the plurality of light emitters (e.g., the first light emitters 1104a-1104d, the second light emitters 1108a-1108d, and the third light emitters 1110a-1 110d) that is radially arranged in the inner cavity 1136, an additional light emitter 1105 that is positioned under the center window 1129. Accordingly, light emitted by the additional light emitter 1105 may exit the optical sensing module 1160 through the center window 1129. The additional light emitter 1105 may be configured to emit light at an infrared wavelength. In variations where the second light emitters 1108a-1108d emit light at an infrared wavelength, the additional light emitter 1105 may be configured to emit light at the same infrared wavelength or a different infrared wavelength as may be desired. The optical sensing module 1100 may operate the additional light emitter 1105 to emit light as part of one or more optical measurements.

[0204] Additionally or alternatively, the optical sensing module 1160 may include a fiducial marker 1107 that is positioned below center window 1129. In these variations, the fiducial marker 1107 may be positioned at a predetermined location on the substrate assembly 1130 (e.g., on substrate 1 131 ) and may be visualized (e.g., using infrared illumination) through the center window 1129. The relative position of the fiducial marker 1107 underneath the center window 1129 may indicate a relative position between the substrate assembly 1130 and a cover assembly of the optical sensing module 1 160. Accordingly, the fiducial marker 1107 may be used to help align the substrate assembly 1130 and the cover assembly (e.g., during manufacturing) and / or may be used to detect misalignment that may occur between the substrate assembly 1130 and the cover assembly (e.g., that may result from a drop event or the like).

[0205] Additionally or alternatively, the optical sensing module 1160 may include a magnet 1 162 that is positioned within the inner cavity 1136, such as described in more detail herein with respect to FIGS. 1C and 19. In variations in which the optical sensing module 1160 includes the center window 1129, at least a portion of the magnet 1 162 may be positioned under the center window 1129.

[0206] Returning to FIGS. 11 A and 11 B, a set of emission optical elements may be positioned over the light emitters of the light emitter array 1134. For example, in variations in which the optical sensing module 1100 includes a plurality of emission windows 1124a-1124h, the optical sensing module 1100 may include a plurality of emission optical elements (e.g., the plurality of emission optical elements 526a-526h of FIG. 6 or the plurality of emission optical elements 726a-726b of FIGS. 7A and 7B). Accordingly, each emission optical element may be positioned between a corresponding emission window and the corresponding light emitter or light emitter group positioned beneath that emission window.

[0207] For example, the plurality of emission optical elements may include a first subset of emission optical elements (e.g., corresponding to the first subset of emission windows 1124b, 1124d, 1124f, 1124h) each of which is positioned over a corresponding light emitter of the plurality of first light emitters 1 104a-1 104d. The plurality of emission optical elements may include a second subset of emission optical elements (e.g., corresponding to the second subset of emission windows 1124a, 1124c, 1124e, 1 124g), each of which is positioned over a corresponding light emitter group of the plurality of light emitter groups 1106a-1106d. In some variations, the first subset of emission optical elements may be configured the same as (e.g., have the same optical properties as) the second subset of emission optical elements. In these variations, the first and second subsets of emission optical elements may have a uniform appearance. In other variations, the first subset of emission optical elements may be configured differently (e.g., may have different optical properties) than the second subset of emission optical elements.

[0208] In some variations, the emission optical elements described herein may each include a micro-optic array that includes a plurality of micro-optics. In some variations, the micro-optic array includes an array of microlenses. For example, FIGS. 14A and 14B show a top view and a partial cross-sectional view (taken alongline 14B-14B), respectively, of a variation of an emission optical element 1400 as described herein. Specifically, the emission optical element 1400 includes a microoptic array 1402 that includes a plurality of microlenses formed in a first surface of the emission optical element 1400. Each microlens of the micro-optic array 1402 may have a corresponding set of optical properties, including a diameter and a focal length. In some variations, each microlens of the micro-optic array 1402 has the same optical properties. In other variations, different microlenses of the micro-optic array 1402 have different optical properties.

[0209] For example, in the variation shown in FIGS. 14A and 14B, the micro-optic array 1402 includes a plurality of first microlenses 1404 having a first set of optical properties, a plurality of second microlenses 1406 having a second set of optical properties, and a plurality of third microlenses 1408 having a third set of optical properties. For example, each of the first microlenses 1404 has a first diameter and a first focal length, each of the second microlenses 1406 has a second diameter smaller than the first diameter and a second focal length, and each of the third microlenses 1408 has a third diameter smaller than the second diameter and a third focal length. In some variations, each of plurality of first microlenses 1404, second microlenses 1406, and third microlenses 1408 are aspheric lenses.

[0210] In some variations, the emission optical element 1400 may include a guard ring 1410 that surrounds the micro-optic array 1402. The guard ring 1410 may be an un-patterned portion of the emission optical element 1400. In instances where the emission optical element 1400 is die cut from a larger piece of material, the guard ring 1410 may reduce or eliminate strain (and resulting deformation) in the microoptic array 1402 when the emission optical element 1400 is die cut.

[0211] In other variations, an emission optical element as described herein may include an array of micro-Fresnel optics. For example, FIGS. 15A and 15B show a top view and a partial cross-sectional view (taken along line 15B-15B), respectively, of a variation of an emission optical element 1500 as described herein. Specifically, the emission optical element 1500 includes a micro-optic array 1502 that includes a plurality of micro-Fresnel optics 1504 formed in a surface of the emission optical element 1500. Each micro-Fresnel optic 1504 includes a microlens 1506 and a set of Fresnel rings 1508 concentrically surrounding the microlens 1506. While the micro-Fresnel optics 1504 are shown in FIGS. 15A and 15B as each having a single corresponding Fresnel ring 1508 surrounding the corresponding microlens 1506, it should be appreciated that in other variations the micro-Fresnel optics may each include a plurality of Fresnel rings 1508 surrounding the corresponding the microlens 1506.

[0212] In some variations, the set of Fresnel rings 1508 and the microlens 1506 of a given micro-Fresnel optics 1504 may have different optical properties. For example, in some variations, the microlens 1506 of each of the micro-Fresnel optics 1504 has a first focal length, whereas each Fresnel ring of the set of Fresnel rings 1508 has a different corresponding focal length than the first focal length. In some variations, the set of Fresnel rings 1508 may be configured to collimate light received from a light emitter (e.g., a light emitter of the light emitter arrays described herein) that is positioned under the emission optical element 1500. In some of these variations the set of Fresnel rings 1508 of each micro-Fresnel optics 1504 is configured to collimate light in a particular direction (e.g., toward an annular detection window of the optical sensing module). In some examples, the emission optical element 1500 may include a guard ring 1510 that surrounds the micro-optics array 1502.

[0213] In still other examples, an emission optical element may include both microlenses and micro-Fresnel optics. For example, FIGS. 16A and 16B show a top view and a partial cross-sectional view (taken along line 16B-16B), respectively, of a variation of an emission optical element 1600 as described herein. Specifically, the emission optical element 1600 includes a micro-optic array 1602 that includes a plurality of micro-Fresnel optics 1604 and a plurality of microlenses. In the variation shown in FIGS. 16A and 16B, the plurality of microlenses includes a plurality of first microlenses 1606 and a plurality of second microlenses 1608, each of which has different optical properties. For example, the first microlenses 1606 may each have a first diameter and a first focal length, and the second microlenses 1608 may each have a second diameter less than the first diameter and a second focal length. Each of the microlenses of the plurality of microlenses is not surrounded by a corresponding set of Fresnel rings.

[0214] As with the emission optical element 1500 of FIGS. 15A and 15B, each of the micro-Fresnel optics 1604 includes a corresponding microlens 1616 and a corresponding set of Fresnel rings 1618a-1618b surrounding the microlens 1616. For example, in the variation shown in FIGS. 16A-16B, the set of Fresnel rings 1618a-1618b includes a plurality of Fresnel rings including a first Fresnel ring 1618a surrounding the microlens 1616 and a second Fresnel ring 1618b surrounding each of the first Fresnel ring 1618a and the microlens 1616. The micro-Fresnel optics 1604 of the emission optical element 1600 may be configured in any manner as described herein with respect to the Fresnel optics 1504 of FIGS. 15A and 15B.

[0215] The micro-Fresnel optics 1604 and the microlenses 1606, 1608 may be arranged in any suitable manner. For example, in the variation shown in FIGS. 16A and 16B, the micro-optic array may include a first micro-Fresnel optic 1604a positioned at a center of the micro-optic array 1602, a first plurality of micro-Fresnel optics 1604b that are radially arranged along a first circle (as indicated by dashed line 1620) to surround the first micro-Fresnel optic 1604a, and a second plurality of micro-Fresnel optics 1604c that are radially arranged along a second circle (as indicated by dashed line 1622) to surround the first plurality of micro-Fresnel optics. Only a single micro-Fresnel optic 1604b of the first plurality of micro-Fresnel optics and a single micro-Fresnel optic 1604c of the second plurality of micro-Fresnel optics are labeled in FIG. 16A. In some variations, each of the first micro-Fresnel optic 1604a, the second plurality of micro-Fresnel optics 1604b, and the third plurality of micro-Fresnel optics 1604c have the same configuration. In other variations, the first plurality of micro-Fresnel optics 1604b may be configured differently from the first micro-Fresnel optic 1604a and / or the second plurality of micro-Fresnel optics 1604c.

[0216] The microlenses of the emission optical element 1600 each may be positioned between a corresponding group of micro-Fresnel optics 1604. In the variation shown in FIGS. 16A and 16B, the micro-optic array 1602 is configured such that the first microlenses 1606 are radially arranged around the center of the microoptic array 1602 (e.g., around the first micro-Fresnel optic 1604a). Each of the first microlenses 1606 is positioned between a corresponding group of micro-Fresnel optics that includes micro-Fresnel optics from each of the first and second plurality of micro-Fresnel optics 1604b, 1604c. The micro-optic array 1602 is further configuredsuch that the second microlenses 1608 are radially arranged around the center of the micro-optic array 1602 (e.g., around the first micro-Fresnel optic 1604a) and are positioned between micro-Fresnel optics of the second plurality of micro-Fresnel optics 1604c. In these variations the first microlenses 1606 are positioned relatively closer to the center of the emission optical element 1600 and the second microlenses 1608 are positioned relatively closer to an outer perimeter of the microoptic array 1602. While not shown in FIG. 16A, the emission optical element 1600 may include a guard ring surrounding the outer perimeter of the micro-optic array 1602 if so desired.

[0217] Any of the optical sensing modules described herein may incorporate an emission optical element such as those described with respect to FIGS. 14A-16B. For example, when an optical sensing module includes a plurality of emission optical elements, some or all of these emission optical elements may be configured such as described herein with respect to FIGS. 14A-16B. For example, when each of the plurality of emission optical elements has a common configuration, each of the plurality of emission optical elements may be configured as the emission optical element 1400 of FIGS. 14A and 14B, may be configured as the emission optical element 1500 of FIGS. 15A and 15B, or may be configured as the emission optical element 1600 of FIGS. 16A and 16B. It should be appreciated that these emission optical elements are illustrative examples, and that the optical sensing modules may include other emission optical elements as may be desired.

[0218] Returning to FIGS. 11 A and 11 B, a detection optical element may be positioned over the plurality of light detectors 1102a-1102h of the light detector array 1132. For example, in variations in which the optical sensing module 1100 includes an annular detection window 1122, the optical sensing module 1100 may include a detection optical element (e.g., the detection optical element 327 of FIG. 3B) that is positioned to cover the annular detection window 1122. Accordingly, the detection optical element is positioned between the annular detection window 1 122 and the plurality of light detectors 1102a-1 102h, such that light that enters the optical sensing module 1100 through the annular detection window 1122 passes through the detection optical element before being measured by the light detector array 1132.

[0219] FIGS. 17A-18C depict examples of detection optical elements that may be used with the optical sensing modules described herein. For example, FIGS. 17A and 17B show a top view and a partial cross-sectional view (taken along line 17B- 17B), respectively, of a variation of a detection optical element 1700 as described herein. The detection optical element 1700 has an annular shape that defines a central aperture 1720 extending therethrough, such that the detection optical element 1700 may be positioned within an outer cavity of an optical sensing module as described herein. The detection optical element 1700 includes a Fresnel lens 1702 that includes a plurality of concentric teeth 1703a-1703c, each of which surrounds the central aperture 1720. Each of the plurality of concentric teeth 1703a- 1703c may be configured to redirect light incident thereon. Depending on the configuration of the Fresnel lens 1702, the detection optical element 1700 may be configured to direct incoming light (e.g., received by an annular detection window of the optical sensing module) onto a light detector array and / or to obscure visibility of components positioned underneath the detection optical element 1700.

[0220] While the Fresnel lens 1702 is shown in FIGS. 17A and 17B as having three concentric teeth 1703a-1703c (e.g., a first concentric tooth 1703a, a second concentric tooth 1703b, and a third concentric tooth 1703c), it should be appreciated that the Fresnel lens 1702 may include more (e.g., four or more) or fewer (e.g., two) concentric teeth as may be desired. Each concentric tooth has a corresponding inner surface 1704 and outer surface 1706, where the inner surface 1704 and outer surface 1706 meet at a corresponding peak 1708. The inner surface 1704 and outer surface 1706 may collectively define a corresponding width w (e.g., within a plane of the detection optical element 1700) and height h (e.g., along a direction normal to the plane of the detection optical element 1700) of the concentric tooth. The inner surface 1704, which may be positioned between the peak 1708 and the central aperture 1720, may be angled relative to the peak 1708 at a first corresponding angle 01. Similarly, the outer surface 1706, which is positioned between the peak 1708 and an outer periphery of the detection optical element 1700, may be angled relative to the peak 1708 at a second corresponding angle 02. While these elements are only labeled for the second concentric tooth 1703b, it should be appreciated that each concentric tooth of the Fresnel lens has its own corresponding inner surface, outer surface, peak, width and height.

[0221] In some variations, the concentric teeth of the plurality of concentric teeth 1703a-1703c have a common configuration. In these variations, each of the plurality of concentric teeth has the same width, heigh, first angle 9i, and second angle 02. In other variations, different concentric teeth of the plurality of concentric teeth 1703a- 1703c have different configurations. For example, in some variations, some or all of the plurality of concentric teeth 1703a-1703c have different widths. Additionally or alternatively, some or all of the plurality of concentric teeth 1703a-1703c have different heights.

[0222] In some variations, the detection optical element 1700 may include a set of guard rings 1710a-1710b, each of which includes an un-patterned portion of the detection optical element 1700. In instances where the detection optical element 1700 is die cut from a larger piece of material, the set of guard rings 1710a-1710b may reduce or eliminate strain (and resulting deformation) in the Fresnel lens 1702 when the detection optical element 1700 is die cut. In the example shown in FIG. 17A, the detection optical element 1700 includes an inner guard ring that surrounds the central aperture 1720 and is positioned between the Fresnel lens 1702 and the central aperture 1720. The detection optical element 1700 may also include an outer guard ring that surrounds each of the Fresnel lens 1702, the inner guard ring 1710a, and the central aperture 1720.

[0223] In some examples, the detection optical element 1700 may be configured to diffuse light that passes through the detection optical element 1700. For example, the detection optical element 1700 may be formed to include scattering particles 1722 and / or voids that are configured to redirect light within the detection optical element 1700. In these instances, the detection optical element 1700 may be translucent, such that light is able to pass through the detection optical element 1700 but obscures the visibility of objects (e.g., light detectors) positioned under the detection optical element 1700.

[0224] For example, FIGS. 18A and 18B show a top view and a partial cross- sectional view (taken along line 18B-18B), respectively, of a variation of a detection optical element 1800 as described herein. The detection optical element 1800 has an annular shape that defines a central aperture 1820 extending therethrough, such that the detection optical element 1800 may be positioned within an outer cavity ofan optical sensing module as described herein. The detection optical element 1800 includes a Fresnel lens 1802 that includes a plurality of radial teeth 1803a-1803c, each of which is positioned along a corresponding direction that intersects the central aperture 1820. Each of the plurality of radial teeth 1803a-1803c may be configured to redirect light incident thereon. Depending on the configuration of the Fresnel lens 1802, the detection optical element 1800 may be configured to direct incoming light (e.g., received by an annular detection window of the optical sensing module) onto a light detector array and / or to obscure visibility of components positioned underneath the detection optical element 1800.

[0225] While only three radial teeth 1803a-1803c (e.g., a first radial tooth 1803a, a second radial tooth 1803b, and a third radial tooth 1803c) are labeled in FIGS. 18A and 18B, it should be appreciated that the Fresnel lens 1802 may include any number of radial teeth as may be needed to collectively surround the central aperture 1820. Each radial tooth has a corresponding first surface 1804 and second surface 1806, where the first surface 1804 and second surface 1806 meet at a corresponding peak 1808. The first surface 1804 and second surface 1806 may collectively define a corresponding width w(e.g., within a plane of the detection optical element 1800) and height h (e.g., along a direction normal to the plane of the detection optical element 1800) of the radial tooth. The first surface 1804, which may be positioned to the left of the peak 1808 as viewed from the central aperture 1820, may be angled relative to the peak 1808 at a first corresponding angle 01. Similarly, the second surface 1806, which is positioned to the right of the peak 1808 as viewed from the central aperture 1820, may be angled relative to the peak 1808 at a second corresponding angle 02. While these elements are only labeled for the second radial tooth 1803b, it should be appreciated that each radial tooth of the Fresnel lens has its own corresponding inner surface, outer surface, peak, width and height.

[0226] In some variations, the plurality of radial teeth 1803a-1803c have a common configuration. In these variations, each of the plurality of radial teeth have the same width, heigh, first angle Oi. and second angle 02. In other variations, different radial teeth of the plurality of radial teeth 1803a-1803c have different configurations. For example, in some variations, some or all of the plurality of radialteeth 1803a-1803c have different widths. Additionally or alternatively, some or all of the plurality of radial teeth 1803a-1803c have different heights.

[0227] In some variations, the detection optical element 1800 may include a set of guard rings 1810a-181 Ob, each of which includes an un-patterned portion of the detection optical element 1800. In instances where the detection optical element 1800 is die cut from a larger piece of material, the set of guard rings 1810a-1810b may reduce or eliminate strain (and resulting deformation) in the Fresnel lens 1802 when the detection optical element 1800 is die cut. In the example shown in FIG. 18A, the detection optical element 1800 includes an inner guard ring that surrounds the central aperture 1820 and is positioned between the Fresnel lens 1802 and the central aperture 1820. The detection optical element 1800 may also include an outer guard ring that surrounds each of the Fresnel lens 1802, the inner guard ring 1810a, and the central aperture 1820.

[0228] In some variations, the Fresnel lens of a detection optical element may include both radial teeth and concentric teeth. For example, FIG. 18C shows a top view of a variation of a detection optical element 1801 that may be configured the same as the detection optical element 1800 of FIGS. 18A and 18B except that the Fresnel lens 1802 further includes a first set of concentric teeth 1812 and a second set of concentric teeth 1814. The first set of concentric teeth 1812 includes one or more concentric teeth, each of which surrounds the central aperture 1820 and may be configured in any manner as described herein with respect to FIGS. 17A and 17B. The first set of concentric teeth 1812 may be positioned between the plurality of radial teeth 1803a-1803c and the central aperture 1820, such that the plurality of radial teeth 1803a-1803c collectively surround the first set of concentric teeth. In variations in which the detection optical element 1801 includes an inner guard ring 1810a, the first set of concentric teeth 1812 may be positioned between the plurality of radial teeth 1803a-1803c and the inner guard ring 1810a, which may improve the manufacturability of the detection optical element 1801 .

[0229] Similarly, the second set of concentric teeth 1814 includes one or more concentric teeth, each of which surrounds the plurality of radial teeth 1803a-1803c and central aperture 1820. Accordingly, each radial tooth of the plurality of radial teeth 1803a-1803c may extend between a corresponding concentric tooth of the firstset of concentric teeth 1812 and a corresponding concentric tooth of the second set of concentric teeth 1814. In variations in which the detection optical element 1801 includes an outer guard ring 181 Ob, the second set of concentric teeth 1814 may be positioned between the plurality of radial teeth 1803a-1803c and the outer guard ring 1810b.

[0230] FIG. 19 depicts an example optical sensing module 1900 that is configured to magnetically couple to an external charging device 1920 for and during a device charging operation. Specifically, the optical sensing module 1900 includes a set of magnets 1910, 1912 that can be used to align the device (e.g., wearable electronic device) with respect to the external charging device 1920 and / or may be used to retain the device to the external charging device 1920. The external charging device 1920 may include a wireless charging accessory such as a wireless charging dock, wireless charging puck, charging pad or surface or another similar device.

[0231] In the present example, the cover member 200 defines a convex contoured exterior surface 1902, which may facilitate some of the measurements or sensing operations described herein. The convex shape may also facilitate alignment with the external charging device 1920, which may have a corresponding concave contoured exterior surface that is configured to receive and contact the surface 1902. The convex shape may have a spherical or revolved shape that allows the device to be coupled to the external charging device 1920 in a variety of orientations. In the present example, the device further includes an alignment magnet 1910, which may be configured to magnetically couple to a corresponding alignment magnet within the external charging device 1920. The magnetic coupling between the alignment magnet 1910 and the corresponding alignment magnet of the external charging device 1920 may help maintain alignment between the two devices along an axis. In this specific example, the alignment magnet 1910 facilitates alignment of the device with respect to an external charging device 1920 along a central axis of the device. While the surface 1902 in this example has a revolved, specifically a spherical, shape, other implementations may have differently shaped external surfaces. In some implementations, the surface 1902 may be a substantially flat or planar surface.

[0232] As shown in FIG. 19, the device also includes a retention magnet 1912, which may help retain the device to the external charging device 1920 during a charging or docking operation. The retention magnet 1912 may magnetically couple to a corresponding magnet or ferritic structure of the external charging device 1920, which may provide an attraction force between the optical sensing module 1900 of the device and the external charging device 1920. In the present example the retention magnet 1912 has a larger mass than the alignment magnet 1910 and / or may provide a larger magnetic field that may be better suited for retaining the device to the external charging device 1920. The retention magnet 1912 may have a smaller mass and may be positioned more closely to the external surface 1902, which may provide improved alignment functionality.

[0233] In the present example, the retention magnet 1912 is positioned on the substrate(s) 331 . Specifically, the retention magnet 1912 is positioned on a side of the substrate(s) 331 that is opposite to a side on which the light emitter array 334 is positioned. The relative location of the retention magnet 1912 may vary in different implementations and, in some cases, the retention magnet 1912 may be positioned on the same side of the substrate(s) 331 as the light emitter array 334 or may be positioned on another component like the cover member 200. In this example, the alignment magnet 1910 is positioned proximate to an inner surface of the cover assembly 720. Specifically, the alignment magnet 1910 is positioned on an integrated optical component 700, which may be positioned on the inner surface of the cover assembly 720. In other implementations, the alignment magnet 1910 may be positioned on an interior coating (e.g., anti-reflective coating 220), which may be included in the cover assembly 720. In other implementations, the alignment magnet may be positioned directly on the cover member 200. The alignment magnet 1910 may be positioned on other components including, for example, the substrate(s) 331 . In the present example, both the alignment magnet 1910 and the retention magnet 1912 are positioned below or inward of the inner transparent portion 202 of the cover member 200. Further, both the alignment magnet 1910 and the retention magnet 1912 are substantially aligned with a central axis of the optical sensing module 1900 and, in this example, also the central axis of the device.

[0234] In some variations, an optical sensing module as described herein may include a single magnet that is configured to act as both the alignment magnet 1910 and the retention magnet 1912 of the FIG. 19. Specifically, some variations of the optical sensing modules described herein may include a tiered magnet. A tiered magnet may have an upper portion and a lower portion, each having a different size and / or shape, and may be positioned in the optical sensing module such that the upper portion extends at least partially through the substrate assembly of the optical sensing module.

[0235] For example, FIG. 21 A shows a perspective view of a tiered magnet 2100 that may be used with the optical sensing modules described herein. The tiered magnet 2100 includes an upper portion 2102 and a lower portion 2104, where upper portion 2102 extends from a top surface of the lower portion 2104 and is smaller than the lower portion 2104. Additionally, the lower portion 2104 may have a larger mass than the upper portion 2102. When the tiered magnet 2100 is positioned in an optical sensing module, such as described herein with respect to FIGS. 22A and 22B, the upper portion 2102 may extend through the substrate assembly of the optical sensing module. This may allow the relatively smaller upper portion 2102 to be positioned closer to the assembly while the relatively larger lower portion 2104 may provide a relatively larger magnetic field. Overall, the tiered magnet 2100 may make efficient use of available space within the optical measurement system.

[0236] The upper portion 2102 and the lower portion 2104 may each have any suitable cross-sectional shape as may be desired. In some variations, the upper portion 2102 and the lower portion 2104 have different cross-sectional shapes. For example of the tiered magnet 2100 shown in FIG. 21 A, the upper portion 2102 has an octagonal cross-sectional shape and the lower portion 2104 has a rectangular cross-sectional shape. Configuring the upper portion 2102 to have an octagonal cross-sectional shape as shown in FIG. 21 A may help to increase the relative size of the upper portion 2102 for a given configuration of a light emitter array, such as described herein with respect to FIGS. 22A and 22B. Depending on the number and placement of light emitters within the optical sensing module, it may be desirable to configure the upper portion 2102 to have a cross-sectional shape that is a polygonhaving a different number of sizes (e.g., a pentagon, a hexagon, a heptagon, or the like).

[0237] FIG. 21 B shows a top view of another variation of a tiered magnet 2110 in which the upper portion 2102 has an octagonal cross-sectional shape (or another polygonal shape, if so desired) and the lower portion 2104 has a circular cross- sectional shape. In other variations, the upper portion 2102 and the lower portion 2104 may have the same cross-sectional shape. For example, FIG. 21 C shows a top view another variation of a tiered magnet 2120 where the upper portion 2102 and the lower portion 2104 each have an octagonal cross-sectional shape.

[0238] FIG. 21 D shows a top view of a variation of a tiered magnet 2130 in which the upper portion 2102 has a circular cross-sectional shape. In these variations, the upper portion 2102 with a circular cross-sectional shape may provide a more uniform magnetic field. In the variation of the tiered magnet 2130 shown in FIG. 21 E, the lower portion 2104 has a circular cross-sectional shape. FIG. 21 E shows a top view another variation of a tiered magnet 2140 in which the upper portion 2102 has a circular cross-sectional shape and the lower portion 2104 has a rectangular cross- sectional shape. It should be appreciated that the tiered magnets 2100, 21 10, 2120, 2130, and 2140 of FIGS. 21A-2E are illustrative examples, and that a tiered magnet may include an upper portion 2102 and a lower portion 2104 having any combination of cross-sectional shapes depending on the specifications of and available space in an electronic device that incorporates the optical sensing module.

[0239] FIG. 22A shows a cross-sectional side view of a variation of an optical sensing module 2200 that includes a tiered magnet 2210. The tiered magnet 2210 may have an upper portion 2202 and a lower portion 2204 that may be configured in any manner such as described herein with respect to the tiered magnets of FIGS. 21 A-21 E. The optical sensing module 2200 may be configured and labeled the same as the optical sensing module 1900 of FIG. 19, except that the substrate(s) 331 has been replaced by a substrate assembly 2230 and the set of magnets 1910, 1912 has been replaced by the tiered magnet 2210. Also shown in FIG. 22A is a controller substrate 140, such as described herein with respect to FIG. 1 C, which is mounted to the substrate assembly 2230.

[0240] FIG. 22B shows a top view of a portion of the optical sensing module 2200 that includes the substrate assembly 2230. The substrate assembly 2230 may be configured and labeled the same as the substrate assembly 1 130 of FIG. 11 A, except that the substrate assembly defines an aperture 2220 that extends through at least one substrate of the substrate assembly 2230. The optical sensing module 2200 further includes an inner barrier wall 1133 and an outer barrier wall 1 135, each of which may be configured in any suitable manner as described herein, and define an inner cavity 1 136 and an outer cavity 1137 surrounding the inner cavity 1 136.

[0241] The aperture 2220 may be positioned to extend through the substrate 1131 within the inner cavity 1 136. Accordingly, the tiered magnet 2210 may be positioned such that upper portion 2202 extends through the aperture 2220 and at least partially into the inner cavity 1 136, whereas the lower portion 2204 is positioned outside of the inner cavity 1 136. To facilitate efficient use of space within the optical sensing module 2200, it may be desirable for the aperture 2220 to have the same cross- sectional shape as the upper portion 2202 of the tiered magnet 2210. For example, in the variation shown in FIG. 22B, the aperture 2220 has an octagonal cross- sectional shape, which may be used in combination with a tiered magnet (e.g., tiered magnet 2100, 2110, or 2120 of FIGS. 21 A-21 C) having an upper portion 2202 with an octagonal cross-sectional shape. Similarly, in variations where the tiered magnet 2210 has an upper portion 2202 with a circular cross-sectional shape (e.g., as described herein with respect to the tiered magnets 2130 and 2140 of FIGS. 21 D and 21 E), the aperture 2220 may have a circular cross-sectional shape.

[0242] In variations where the aperture 2220 has a cross-sectional shape that is a polygon, different sides of the aperture 2220 may be aligned with corresponding emitters of an emitter array. Specifically, the optical sensing module 2200 is shown in FIG. 22B as having a light emitter array 1134, such as described herein with respect to the optical sensing module 1 100 of FIG. 11 A. The aperture 2220 is shown in FIG. 22B as having a plurality of sides 2221 a-2221 h, each of which is aligned with the corresponding light emitter of the light emitter array 1 134 (e.g., the corresponding light emitter of the light emitter array 1 134 that is positioned closest to the aperture 2220).

[0243] For example, some of the sides of the aperture 2220 may be positioned closest to and aligned with a corresponding light emitter group of the plurality of light emitter groups 1 106a-1 106d. In these instances, the side of the aperture 2220 may be parallel to a corresponding side of one or more light emitters of the light emitter group. For example, a first side 2221a of the aperture 2220 is positioned closest to the light emitter group 1 106a, and is positioned such that the first side 2221 a is parallel to a corresponding side of each of the second light emitter 1108a and the third light emitter 1 1 10a of the first light emitter group 1 106a (as well as parallel to a corresponding side of the first corresponding electrode pad 1 1 12a). Similarly, a third side 2221 c of the aperture 2220 is positioned closest to and aligned with the light emitter group 1106b, a fifth side 2221 e of the aperture 2220 is positioned closest to and aligned with the third light emitter group 1 106c, and a seventh side 2221 g of the aperture 2220 is positioned closest to and aligned with the fourth light emitter group 1106d.

[0244] Similarly, other sides of the aperture 2220 may be positioned closest to and aligned with a corresponding first light emitter of the plurality of first light emitters 1104a-1 104d. For example, a second side 2221 b of the aperture 2220 is positioned closest to the first light emitter 1 104a, such that the second side 2221 b is parallel to a corresponding side of the first light emitter 1 104b. Similarly, a fourth side 2221 d of the aperture 2220 is positioned closest to and aligned with the first light emitter 1104b, a sixth side 2221 f of the aperture is positioned closest to and aligned with the first light emitter 1 104c, and an eighth side 2221 h of the aperture is positioned closest to and aligned with the first light emitter 1104d. Configuring the aperture 2220 in this manner may allow for a larger upper portion 2202 of the tiered magnet 2210 while still allowing for a threshold minimum offset between the aperture 2220 and the light emitters of the light emitter array 1 134.

[0245] Returning to FIG. 22A, the tiered magnet 2210 may be connected to one or more components of the optical sensing module 2200 to hold the tiered magnet 2210 in place with the optical sensing module 2200. Specifically, the upper portion 2202 of the tiered magnet 2210 may be positioned proximate to an inner surface of the cover assembly 720. In the variation shown in FIG. 22A, the optical sensing module 2200 includes an integrated optical component 700, and the upper portion 2202 of thetiered magnet 2210 is connected to the integrated optical component 700 via corresponding adhesive layer 2206. In other implementations, the upper portion 2202 of the tiered magnet 2210 may be connected directly to the cover member 200 via the adhesive layer 2206. In still other implementations, the upper portion 2202 of the tiered magnet 2210 may be placed in contact with the integrated optical component 700, an interior coating (e.g., anti-reflective coating 220), or the cover member 200 without an intervening adhesive layer 2206. Further, the upper portion 2202 of the tiered magnet 2210 may be substantially aligned with a central axis of the optical sensing module 2000 and, in some examples, also the central axis of an electronic device incorporating the optical sensing module 2200.

[0246] In instances where the optical sensing module 2200 includes an adhesive layer 2206 between the upper portion 2202 of the tiered magnet 2210 and another component of the optical sensing module 2200 (e.g., the integrated optical component 700 or the cover member 200), it may be desirable to configure the adhesive layer 2206 to be relatively thin (e.g., on the order of tens of microns) to allow the upper portion 2202 of the tiered magnet 2210 to be positioned closer to the cover member 200. This may help to increase the attractive force between the tiered magnet 2210 and an external charging device. In these instances, as well as in instances where the upper portion 2202 of the tiered magnet 2210 is not connected to another component via an adhesive layer 2206, it may be desirable to provide an additional connection point between the tiered magnet 2210 and other components of the optical sensing module 2200.

[0247] For example, in some variations, the optical sensing module 2200 may include a set of adhesive regions 2208 that connects the lower portion 2204 of the tiered magnet 2210 to another component of the optical sensing module 2200. For example, in the variation shown in FIG. 22A, the set of adhesive regions 2208 may connect the lower portion 2204 of the tiered magnet 2210 to the controller substrate 140. The set of adhesive regions 2208 may include a single adhesive region that at least partially surrounds (and, in some instances, fully surrounds) the lower portion 2204 of the tiered magnet 2210. In other instances, the set of adhesive regions 2208 may include multiple discrete (e.g., noncontiguous) adhesive regions, each of which connects a corresponding region of the tiered magnet 2210 to a correspondingregion of the controller substrate 140. In some of these implementations, each adhesive region is formed from the same material. In other implementations, different adhesive regions may be formed from different materials (e.g., one or more adhesive regions may be formed from a first adhesive that is electrically conductive and one or more adhesive regions may be formed from a second adhesive that is non electrically conductive). In still other implementations, the set of adhesive regions 2208 may include multiple contiguous adhesive regions that are formed from different materials, such as described herein with respect to FIG. 23B. It should be appreciated that electrical components (e.g., electrical components 2222 shown in FIG. 22A or the optical sensor controller 144 shown in FIG. 1 C) positioned on a rear surface of the controller substrate 140, as well as any material encapsulating these electronic components, may be positioned with enough clearance from the aperture 146 (defined to extend through the controller substrate 140) to allow for the set of adhesive regions 2208 to contact the rear surface of the controller substrate 140. Accordingly, a top surface of the controller substrate 140 may be mounted to the substrate assembly 2230, and the lower portion 2204 of the tiered magnet 2210 may be mounted to the rear surface of the controller substrate 140 via the set of adhesive regions 2208.

[0248] In some instances, it may be desirable to limit contact between the substrate assembly 2230 and the tiered magnet 2210 (e.g., contact between the substrate 1131 and the tiered magnet 2210), either directly or indirectly via adhesives such as the set of adhesive regions 2208. This may help to reduce the amount of stress applied to the substrate 1131 during assembly (e.g., as the tiered magnet 2210 is connected to the optical sensing module 2200) and / or during the lifetime of the optical sensing module 2200, which may negatively affect the performance of the optical sensing module 2200. Accordingly, in some implementations, the tiered magnet 2210 may be positioned in the optical sensing module 2200 such that the lower portion 2204 of the tiered magnet 2210 is separated from the substrate 1131 by a separation height h. Accordingly, the separation height h may define a gap between a top surface of the lower portion 2204 of the tiered magnet 2210 and a rear surface of the substrate 1131. In some instances, the separation height h may be selected such that the lower portion 2204 of the tiered magnet 2210 partially extends into the aperture 146 of the controllersubstrate 140, such that a portion of the controller substrate 140 is coplanar with the lower portion 2204 of the tiered magnet 2210. Additionally, in some instances it may be desirable to configure the set of adhesive regions 2208 to minimize or reduce the amount of adhesive that enters the gap between the lower portion 2204 of the tiered magnet 2210 and the rear surface of the substrate 1131.

[0249] Depending on the design and operating of the optical sensing module 2200, the presence of the tiered magnet 2210 in close proximity to the other components of the optical sensing module 2200 (e.g., light emitters such as light emitter array 1134, light detectors such as light detector array 1132, and / or electrodes such as the electrodes 125a-125b) may negatively impact sensing operations performed by these components. Accordingly, it may be desirable to connect the tiered magnet 2210 to a predetermined electric potential (e.g., ground). For example, FIG. 23A shows a perspective view of a variation of a tiered magnet 2300 having an upper portion 2302 and a lower portion 2304, each of which may be configured in any manner as described herein with respect to FIGS. 21 A-21 E. The tiered magnet 2300 may be at least partially covered with an electrically conductive coating 2306 (shown in FIG. 23A with cross-hatching for purpose of illustration). For example, the electrically conductive coating 2306 may include a set of metal layers that are plated on the tiered magnet 2300 (e.g., onto an underlying bulk material, such as a rare-earth magnet formed Neodymium-lron-Boron or the like). For example, nickel-copper-nickel plating may be used to form the electrically conductive coating 2306 (e.g., a first nickel layer is plated onto underlying bulk material, a copper layer is plated onto the first nickel layer, and a second nickel layer is plated onto the copper layer).

[0250] When the tiered magnet 2300 is incorporated into an optical measurement system, the electrically conductive coating 2306 may be electrically connected to a controller substrate, which may allow the controller substrate to control an electrical potential of the electrically conductive coating 2306. For example, FIG. 23B shows a rear view of an optical sensing module 2310 as described herein. The optical sensing module 2310 may be configured in any manner as described herein with respect to the optical sensing module 2200 of FIGS. 22A and 22B. As shown in FIG. 23B, the optical sensing module 2310 may include a controller substrate 140 asdescribed in more detail herein with respect to FIG. 1 C. The controller substrate 140 may include an electrical contact 2314 (in addition to other electrical contacts 142) that may be electrically connected to the electrically conductive coating 2306 of the tiered magnet 2300. The electrical contact 2314 may, in turn, be connected to the optical sensor controller 144 (as shown in FIG. 23B) or one of the electrical contacts 142, such that the electrical contact 2314 may receive a reference potential Vref. By virtue of being electrically connected to the electrical contact 2314, the electrically conductive coating 2306 of the tiered magnet 2300 may be thereby held at the reference potential Vref. It should be appreciated that the reference potential Vref may be any suitable electric potential (e.g., system ground, a supply voltage, or the like). Additionally, the reference potential Vref may be fixed during operation of the optical sensing module 2310, or may be varied (e.g., by the optical sensor controller 144) during operation of the optical sensing module 2300.

[0251] The electrically conductive coating 2306 may be electrically connected to the electrical contact 2314 in any suitable manner. For example, in the variation of the optical sensing module 2310 shown in FIG. 23B, the optical sensing module 2310 includes a set of adhesive regions 2312 that connects the lower portion 2304 of the tiered magnet 2300. In these instances, the set of adhesive regions 2312 includes a first adhesive region 2312a that is formed from an electrically conductive adhesive. The first adhesive region 2312a may contact both the electrical contact 2314 and the electrically conductive coating 2306, and thereby electrically connects the electrically conductive coating 2306 to the first adhesive region 2312a. In some variations, the first adhesive region 2312a may fully surround the lower portion 2304 of the tiered magnet 2300. In other variations, the set of adhesive regions 2312 may include one or more additional adhesive regions that are formed from a non- conductive adhesive. For example, in the variation shown in FIG. 23B, the set of adhesive regions 2312 includes a second adhesive region that is formed from a non- conductive adhesive. In some implementations, the first adhesive region 2312a and the second adhesive region 2312b are contiguous. For example, in the variation shown in FIG. 23B, the first adhesive region 2312a and the second adhesive region 2312b collectively fully surround the lower portion 2304 of the tiered magnet 2300. In other variations, the first adhesive region 2312a and the second adhesive region 2312b may be noncontiguous.

[0252] When the upper portion of a tiered magnet is positioned to extend into an inner cavity (e.g., inner cavity 1136) of an optical sensing module, light emitted by light emitters (e.g., of the light emitter array 1134) may be incident on the tiered magnet. Light reflecting off of the tiered magnet may exit the optical sensing module along unintended trajectories, and thus it may be desirable to reduce the amount of light that reflects off the tiered magnet. In some variations, it may be desirable to cover at least a portion of a tiered magnet with an opaque coating (e.g., an ink coating). For example, in the variation of the tiered magnet 2300 shown in FIG. 23A, the tiered magnet 2300 may be partially covered with an opaque coating 2308. The opaque coating 2308 may be configured to cover at least the upper portion 2302 of the tiered magnet 2300, such that the portion of the tiered magnet 2300 that is positioned inside the inner cavity of the optical sensing module (e.g., optical sensing module 2300) is covered with the opaque coating 2308. In some variations, at least a portion of the top surface of the lower portion 2304 of the tiered magnet 2300 may also be coated with the opaque coating 2308.

[0253] In some instances, the entire tiered magnet 2300 may be coated with the opaque coating 2308. In other instances, the tiered magnet 2300 may be partially coated with the opaque coating 2308. For example, in instances where the tiered magnet also includes an electrically conductive coating 2306, such as shown in FIG. 23A, it may be desirable to allow for a portion of the electrically conductive coating 2306 to remain exposed (e.g., to allow for electrical connection between the electrically conductive coating 2306 and the electrical contact 2314). In these instances, the opaque coating 2308 may be positioned over a first portion of the electrically conductive coating 2306 while leaving a second portion of the electrically conductive coating exposed.

[0254] The optical sensing modules described herein may be used to perform a range of different optical measurements. For example, the optical sensing modules may perform one or more heart rate measurements, blood oxygen saturation measurements, proximity measurements, and / or gesture measurements. Examples of each of these will be discussed with respect to the optical sensing module 1100 of FIGS. 11 A and 11 B, though it should be appreciated that any of the optical sensing modules described herein may perform these measurements. In one example, theoptical sensing module 1 100 may be configured to perform a first heart rate measurement using a first wavelength (e.g., a green wavelength) emitted by the optical sensing module. During the first heart rate measurement, the optical sensing module may collect one or more measurement signals while the plurality of first light emitters 1104a-1104d is operated to emit light of the first wavelength.

[0255] The first heart rate measurement may be performed using only one of the first light emitters 1104a-1104d or using multiple of the first light emitters 1104a- 1104d. In some examples, the optical sensing module 1100 is configured to generate, as part of the first heart rate measurement, a corresponding set of measurement signals for each first light emitter of the plurality of first light emitters 1104a-1104d. In these examples, the optical sensing module 1100 may be configured to, during the first heart rate measurement, operate the plurality of first light emitters 1 104a-1104d in a time-multiplexed manner such that only one first light emitter is actively emitting light at a time. Accordingly, the optical sensing module 1100 may, as part of the first heart rate measurement, generate a first set of measurement signals when one of the first light emitters (e.g., first light emitter 1104a) is generating light, generate a second set of measurement signals when another of the first light emitters (e.g., the first light emitter 1104b) is generating light, and so on. Collectively, these measurement signals may be analyzed to determine the timing and / or characteristics of a user’s individual heartbeats. The timing of the user’s heartbeats may be used to derive information about a user’s cardiac function, such as a user’s heart rate and / or heart rate variability during the first heart rate measurement.

[0256] Additionally, each of the first light emitters 1104a-1104d may be associated with a different corresponding subset of the plurality of light detectors 1102a-1102h, such that each corresponding set of measurement signals is generated using the corresponding subset of the plurality of light detectors 1102a-1102h. For example, when the first light emitter 1104a is generating light, a first subset of light detectors that includes the closest pair of light detectors for the first light emitter 1104a (e.g., light detectors 1102a, 1 102b) may be operated to generate the first set of measurement signals. Similarly, when the first light emitter 1104b is generating light, a second subset of light detectors that includes the closest pair of light detectors forthe first light emitter 1104b (e.g., light detectors 1102c, 1102d) may be operated to generate the second set of measurement signals, and so on.

[0257] In some examples, the optical sensing module 1100 may be configured to perform a second heart rate measurement using a second wavelength (e.g., a wavelength) emitted by the optical sensing module 1100. Specifically, the optical sensing module may collect one or more measurement signals while the plurality of second light emitters 1108a-1108d is operated to emit light of the second wavelength.

[0258] The second heart rate measurement may be performed using only one of the second light emitters 1108a-1108d or using multiple of the second light emitters 1108a-1108d. In some examples, the optical sensing module 1100 is configured to generate, as part of the second heart rate measurement, a corresponding set of measurement signals for each second light emitter of the plurality of second light emitters 1108a-1108d. In these examples, the optical sensing module 1100 may be configured to, during the second heart rate measurement, operate the plurality of second light emitters 1108a-1108d in a time-multiplexed manner such that only one second light emitter is actively emitting light at a time. Accordingly, the optical sensing module 1 100 may, as part of the second heart rate measurement, generate a first set of measurement signals when the second light emitter 1108a is generating light, generate a second set of measurement signals when the second light emitter 1108b is generating light, and so on. As with the first heart rate measurement, these measurement signals may collectively be analyzed to determine the timing and / or characteristics of a user's individual heartbeats.

[0259] Additionally, each of the second light emitters 1 108a-1108d may be associated with a different corresponding subset of the plurality of light detectors 1102a-1102h, such that each corresponding set of measurement signals is generated using the corresponding subset of the plurality of light detectors 1102a- 1102h. In some examples, each second light emitter may be associated with a corresponding subset of light detectors that includes the closest pair of light detectors for that second light emitter. In other examples, each second light emitter may be associated with a corresponding subset of light detectors that includes the four light detectors that are closest to that second light emitter. In these examples,when the second light emitter 1108a is generating light, a first subset of light detectors that includes light detectors 1102a, 1102b, 1102g and 1102h may be operated to generate the first set of measurement signals. Similarly, when the second light emitter 1108b is generating light, a second subset of light detectors that includes light detectors 1 102a, 1 102b, 1102c, and 1102d may be operated to generate the second set of measurement signals, and so on.

[0260] The optical sensing module 1100 may be configured to perform both the first and second heart rate measurements, and may perform these heart rate measurements under different circumstances. For example, the optical sensing module 1100 may consume more power when performing the first heart rate measurement as compared to performing the second heart rate measurement, and thus may be configured to perform the second heart rate measurement more frequently than the first heart rate measurement. In some instances, the first heart rate measurement may be performed under certain conditions, such as when a user is exercising (e.g., as indicated by a user input or as detected by an electronic device incorporating the optical sensing module 1100) or wishes to make an on-demand heart rate measurement. Conversely, the optical sensing module 1100 may perform the second heart rate measurement periodically while an electronic device incorporating the optical sensing module 1100 is worn by a user. In this way, the optical sensing module 1100 may obtain background heart rate measurements over time.

[0261] In some instances, the optical sensing module 1100 is configured to perform a blood oxygen saturation measurement using the second wavelength (e.g., an infrared wavelength) and the third wavelength (e.g., a red wavelength). Specifically, the optical sensing module 1100 may collect one or more measurement signal pairs while the plurality of light emitter groups 1106a-1106d is operated to emit light of the second and the third wavelength.

[0262] The blood oxygen saturation measurement may be performed using only one of the light emitter groups 1106a-1106d or using multiple of the light emitter groups 1106a-1106d. In some examples, the optical sensing module 1100 is configured to generate, as part of the blood oxygen saturation measurement, a corresponding set of measurement signal pairs for each light emitter group of theplurality of light emitter groups 1106a-1106d. Each measurement signal pair includes i) a first measurement signal generated by a corresponding light detector while a second light emitter emits the second wavelength and ii) a second measurement signal generated by the corresponding light detector while the third light emitter emits the third wavelength. To the extent that multiple light detectors are operated to generate signals for a given light emitter group, each light detector may generate a corresponding measurement signal pair.

[0263] For example, each light emitter group of the plurality of light emitter groups 1106a-1106d may be associated with a corresponding subset of the plurality of light detectors 1102a-1102h. In some examples, each of the light emitter groups 1106a- 1106d is associated with a corresponding subset of light detectors that includes the four closest light detectors of the plurality of light detectors 1102a-1102h. The light emitter group 1106a may be operated to emit light at the second and third wavelengths (e.g., using the second light emitter 1108a and the third light emitter 1110a) in a time-multiplexed manner during the blood oxygen saturation measurement, and a corresponding first subset of detector elements that include light detectors 1102g, 1 102h, 1102a, and 1102b may be operated to generate a first set of measurement signal pairs. Similarly, the light emitter group 1106b may be operated to emit light at the second and third wavelengths (e.g., using the second light emitter 1108b and the third light emitter 1110b) in a time-multiplexed manner during the blood oxygen saturation measurement, and a corresponding second subset of detector elements that include light detectors 1102a, 1102b, 1102c, and 1102d may be operated to generate a second set of measurement signal pairs. A third subset of detectors including light detectors 1102c, 1102d, 1102e, and 1102f may generate a third set of measurement signal pairs using light emitted by the light emitter group 1106c, and a fourth subset of detectors including light detectors 1102e, 1102f, 1102g, and 1102h may generate a fourth set of measurement signal pairs using light emitted by the light emitter group 1106d. The various measurement signal pairs may be analyzed (e.g., by taking a ratio of the measurement signals within each pair) to determine a blood oxygen saturation of the user.

[0264] In some instances, the optical sensing module 1100 may perform one or more proximity measurements that may measure a distance and / or an orientation ofthe optical sensing module 1100 (and with it, an electronic device incorporating the optical sensing module 1 100) relative to a user. In one example, a proximity measurement includes generating one or more measurement signal pairs, where each measurement signal pair is generated by a corresponding pair of light detectors of the light detector array 1 132 while a corresponding light emitter of the light emitter array 1134 is generating light. A ratio of each measurement signal pair may represent a distance between a particular portion of the optical sensing module 1100 and a user’s wrist (or another object positioned in proximity to the optical sensing module 1100). To the extent that multiple measurement signal pairs are generated as part of a proximity measurement, the ratios of the measurement signal pairs may collectively be used to determine an orientation of the optical sensing module 1100 relative to the user's wrist. In some examples, the proximity measurement may be performed using the second wavelength of light (e.g., an infrared wavelength) generated by one or more second light emitters of the plurality of second light emitters 1108a-1108d. In these examples, each measurement signal pair may be generated while a different corresponding second light emitter is emitting light.

[0265] The optical sensing module 1100 may, in some instances, perform a gesture detection measurement. Specifically, during a gesture detection measurement, one or more measurement signals may be analyzed to detect a gesture performed by the user. Each measurement signal of a gesture detection measurement may be generated by one or more light detectors of the light detector array 1132 while one or more light emitters of the light emitter array 1134 are operated to generate light. Collectively, the measurement signals may be analyzed to detect changes in the measurement signals that occur as a result of a user gesture (e.g., changes in blood flow that may result from movement of the muscles and tendons in a user’s wrist). In one non-limiting example, a user gesture may include a user tapping two or more fingers together.

[0266] The electronic devices described may, in some instances, be used to obtain personal data from a user, including physiological information and other personally identifiable information data. The use of personally identifiable information should follow privacy practices and policies that are generally recognized as meeting or exceeding governmental or industry requirements as may be set to maintain theprivacy of users. In particular, personally identifiable information / data should be handled and managed in a manner so as to minimize risks of unauthorized or unintentional access or use by others, and the nature of authorized use should be clearly indicated to users.

Claims

CLAIMSWhat is claimed is:1 . An electronic watch, comprising: a display assembly including a touch-sensitive layer; a front cover positioned over the display assembly; a housing coupled to the front cover; an optical sensing module at least partially defining a rear surface of the electronic watch, the optical sensing module comprising: a light emitter configured to emit light from the optical sensing module; a plurality of light detectors configured to detect light that enters the optical sensing module; and a co-molded cover member coupled to the housing and comprising: a first portion that partly defines an emission window positioned over the light emitter, the first portion formed from a first transparent zirconia material and defining a first tapered cross-section; a second portion that partly defines a detection window positioned over the plurality of light detectors, the second portion formed from a second transparent zirconia material and defining a second tapered cross-section, the second portion defining an annular shape; and a barrier portion positioned between and bonded to each of the first portion and the second portion and formed from a zirconia material that is opaque with respect to the light emitted from and entering the optical sensing module.

2. The electronic watch of claim 1 , wherein: the light emitter is one of a plurality of light emitters; the plurality of light emitters comprises: a set of first light emitters configured to emit a first wavelength of light in a range of green wavelengths; a set of second light emitters configured to emit a second wavelength of light in a range of infrared wavelengths;a set of third light emitters configured to emit a third wavelength of light in a range of red wavelengths; and the first and second transparent zirconia materials transmit the first, second, and third wavelengths of light; and the zirconia material of the barrier portion comprises a coloring agent that absorbs light in at least the first, second, and third wavelengths of light.

3. The electronic watch of claim 2, wherein: the first portion defines a circular perimeter at an exterior surface of the comolded cover member; the barrier portion defines a minimum spacing between the first and the second portions of the co-molded cover member at the exterior surface of the comolded cover member; and the minimum spacing between the first portion and the second portion is less than a maximum thickness of the barrier portion.

4. The electronic watch of claim 3, wherein the minimum spacing between the first portion and the second portion is greater than 0.5 mm and less than 3 mm.

5. The electronic watch of claim 3, wherein the zirconia material of the barrier portion has an optical density in a range from 2 to 6 per millimeter of thickness.6 The electronic watch of claim 3, wherein a coefficient of thermal expansion of the first and second transparent zirconia materials is matched to a coefficient of thermal expansion of the zirconia material of the barrier portion.

7. The electronic watch of claim 1 , further comprising an inorganic anti- reflective coating disposed over an interior surface of the co-molded cover member and partly defining each of the emission window and the detection window.

8. An electronic device comprising: a display assembly; a light emitter array;a light detector array; and an enclosure surrounding the display assembly, the light emitter array, and the light detector array, the enclosure including a ceramic cover member defining at least a portion of a rear surface of the electronic device, the ceramic cover member comprising: a first barrier portion formed from a first zirconia material; a first window portion positioned over at least one light emitter of the light emitter array and formed from a second zirconia material, the first barrier portion surrounding and integrally formed with the first window portion; a second window portion positioned over the light detector array, surrounding and integrally formed with the first barrier portion, and formed from a third zirconia material; and a second barrier portion surrounding and integrally formed with the second window portion, the second barrier portion formed from a fourth zirconia material.

9. The electronic device of claim 8, wherein: the first window portion is positioned over a respective light emitter of the light emitter array; the first window portion flares outward from an interior surface to an exterior surface of the ceramic cover member; and the second window portion flares outward from the interior surface to the exterior surface of the ceramic cover member.

10. The electronic device of claim 9, wherein: the first window portion is diffusion-bonded to the first barrier portion at a first interface; and the second window portion is diffusion-bonded to the first barrier portion at a second interface.1 1 . The electronic device of claim 10, wherein: the first interface defines a first angle with respect to a first normal to the interior surface; the second interface defines a second angle with respect to a second normal to the interior surface; and each of the first angle and the second angle is in a range from 1 degree to 20 degrees.

12. The electronic device of claim 8, wherein: each of the second and the third zirconia materials is a transparent polycrystalline zirconia material that comprises at least 90% of a cubic zirconia phase; and each of the first and the fourth zirconia materials is an opaque polycrystalline zirconia material comprising a pigment.

13. The electronic device of claim 12, wherein: each of the second and the third zirconia materials is a first same zirconia material; and each of the first and the fourth zirconia materials is a second same zirconia material.

14. The electronic device of claim 8, wherein: the ceramic cover member comprises a set of first window portions, each first window portion of the set of first window portions positioned over at least one or more respective light emitters of the light emitter array; and the first barrier portion surrounds each first window portion of the set of first window portions.

15. A wearable device, comprising: a housing; a front cover coupled to the housing; a display assembly positioned below the front cover and at least partially surrounded by the housing; an optical sensing module comprising:- I l l -a plurality of light emitters; a plurality of light detectors; and a rear cover member comprising: an inner opaque portion formed from a first zirconia material and defining a first annular shape; an inner transparent portion formed from a second zirconia material and positioned over the plurality of light emitters, the inner transparent portion bonded to an inner face of the inner opaque portion; an outer transparent portion formed from a third zirconia material, positioned over the plurality of light detectors, and defining a second annular shape, an inner face of the outer transparent portion bonded to an outer face of the inner opaque portion; and an outer opaque portion formed from a fourth zirconia material and bonded to an outer face of the outer transparent portion.

16. The wearable device of claim 15, wherein: the rear cover member is integrally formed from the inner and the outer opaque portions and the inner and the outer transparent portions; the inner and the outer faces of the inner opaque portion partly define a cross- sectional shape of the inner opaque portion; and the cross-sectional shape of the inner opaque portion is tapered and defines a top width that is less than a bottom width of the inner opaque portion.

17. The wearable device of claim 16, wherein: the inner transparent portion is molded to the inner face of the inner opaque portion; and the outer transparent portion is molded to the outer face of the inner opaque portion.

18. The wearable device of claim 16, wherein: the plurality of light detectors define an operating range of wavelengths; and the outer transparent portion has a transmittance of at least 65% over the operating range of wavelengths.

19. The wearable device of claim 16, wherein the optical sensing module further comprises: an emission optical element positioned between the inner transparent portion and the plurality of light emitters; and a detection optical element positioned between the outer transparent portion and the plurality of light detectors.

20. The wearable device of claim 15, wherein: the inner opaque portion defines an inner barrier that protrudes with respect to each of the inner transparent portion and the outer transparent portion at an interior surface of the rear cover member; and the outer opaque portion defines an outer optical barrier that protrudes with respect to the outer transparent portion at the interior surface of the rear cover member.21 . An electronic device comprising: an optical sensing module defining an inner cavity and an outer cavity surrounding the inner cavity, the optical sensing module comprising: a cover assembly defining a set of emission windows and an annular detection window surrounding the set of emission windows; a light emitter array positioned in the inner cavity and behind the set of emission windows; and a plurality of light detectors positioned in the outer cavity and behind the annular detection window, wherein each light detector of the plurality of light detectors has a trapezoidal shape.

22. An electronic device comprising: an optical sensing module defining an inner cavity and an outer cavity surrounding the inner cavity, the optical sensing module comprising: a cover assembly defining a plurality of emission windows and an annular detection window surrounding the plurality of emission windows; a light detector array positioned in the outer cavity and behind the annular detection window; anda plurality of light emitters positioned in the inner cavity, the plurality of light emitters comprising: a plurality of first light emitters configured to emit a first wavelength of light; a plurality of second light emitters configured to emit a second wavelength of light; and a plurality of third light emitters configured to emit a third wavelength of light, wherein: the plurality of emission windows comprises a first subset of emission windows and a second subset of emission windows; each emission window of the first subset of emission windows is positioned over a corresponding first light emitter of the plurality of first light emitters; each emission window of the second subset of emission windows is positioned over a corresponding second light emitter of the plurality of second light emitters; and each emission window of the second subset of emission windows is positioned over a corresponding third light emitter of the plurality of third light emitters.

23. An electronic device comprising: an optical sensing module defining an inner cavity and an outer cavity surrounding the inner cavity, the optical sensing module comprising: a cover assembly defining a plurality of emission windows and a detection window and comprising a plurality of emission optical elements positioned within the inner cavity; a light detector array positioned in the outer cavity; and a light emitter array positioned in the inner cavity, wherein: each emission optical element of the plurality of emission optical elements is positioned over a corresponding emission window of the plurality of emission windows and comprises a corresponding plurality of microFresnel optics.

24. An electronic device comprising:an optical sensing module defining an inner cavity and an outer cavity surrounding the inner cavity, the optical sensing module comprising: a cover assembly defining a plurality of emission windows and a detection window; a light detector array positioned in the outer cavity; and a light emitter array positioned in the inner cavity, wherein: the cover assembly comprises: a cover member; an aperture layer attached to an interior surface of the cover member and defining a plurality of apertures, each aperture of the plurality of apertures at least partially defining a corresponding emission window of the plurality of emission windows; and a plurality of emission optical elements, each positioned at least partially within a respective aperture of the plurality of apertures, wherein each emission optical element of the plurality of emission optical elements comprises a corresponding micro-optic array.

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