PATENT DOCUMENT

Publication Number: US-11835382-B2
Application Number: US-202117471851-A
Country: US
Kind Code: B2

Title: Handheld electronic device

Abstract:
A portable electronic device includes a housing, a front cover defining a front side of the portable electronic device, a display stack below the front cover and comprising a plurality of display layers configured to produce a graphical output in a display region of the display stack, the graphical output visible through the front cover, and a light sensor module positioned at least partially within the housing and coupled to the display stack in the display region. The light sensor module may be configured to receive ambient light passing through the front cover and through the plurality of display layers and, while a blanking interval is positioned over the light sensor module, produce an output corresponding to the received ambient light, the portable electronic device configured to determine an ambient light value based at least in part on the output from the light sensor module.

Claims:
What is claimed is: 
     
       1. A portable electronic device comprising:
 a housing; 
 a front cover coupled to the housing and defining a front side of the portable electronic device; 
 a display stack below the front cover and comprising a plurality of display layers configured to produce a graphical output in a display region of the display stack, the graphical output visible through the front cover; and 
 a light sensor module positioned at least partially within the housing and coupled to the display stack in the display region, the light sensor module configured to:
 receive ambient light passing through the front cover and through the plurality of display layers; and 
 while a blanking interval is positioned over the light sensor module, produce an output corresponding to the received ambient light, the portable electronic device configured to determine an ambient light value based at least in part on the output from the light sensor module. 
 
 
     
     
       2. The portable electronic device of  claim 1 , wherein:
 the portable electronic device further comprises a camera positioned in a front-facing sensor region of the front side of the portable electronic device and configured to capture images through the front cover; and 
 the light sensor module is proximate the front-facing sensor region. 
 
     
     
       3. The portable electronic device of  claim 1 , wherein the ambient light value is a color temperature of the ambient light. 
     
     
       4. The portable electronic device of  claim 3 , wherein the portable electronic device is further configured to change a display parameter of the display stack based at least in part on the ambient light value. 
     
     
       5. The portable electronic device of  claim 1 , wherein the blanking interval is a vertical blanking interval. 
     
     
       6. The portable electronic device of  claim 1 , wherein:
 at least one of the plurality of display layers comprises electrodes; 
 the electrodes are arranged in a first pattern in an area above the light sensor module; and 
 the electrodes are arranged in a second pattern different from the first pattern in an area remote from the light sensor module. 
 
     
     
       7. The portable electronic device of  claim 6 , wherein the first pattern corresponds to a first subset of the electrodes being layered on top of a second subset of the electrodes. 
     
     
       8. A mobile phone comprising:
 a housing; 
 a transparent cover coupled to the housing; 
 a display stack at least partially within the housing and positioned below the transparent cover, the display stack comprising:
 a plurality of display layers configured to produce a graphical output visible through the transparent cover; and 
 an opaque masking layer positioned below the plurality of display layers and defining a hole; and 
 
 a light sensor module coupled to the display stack and configured to:
 receive ambient light that passes through the transparent cover, the plurality of display layers, and the hole in the opaque masking layer; and 
 produce an output corresponding to the received ambient light, the mobile phone configured to determine a color temperature of the ambient light based at least in part on the output from the light sensor module. 
 
 
     
     
       9. The mobile phone of  claim 8 , wherein an area of the hole in the opaque masking layer is smaller than an area of a light sensing element of the light sensor module. 
     
     
       10. The mobile phone of  claim 8 , wherein:
 the plurality of display layers define a plurality of pixels configured to be selectively illuminated to produce the graphical output, the plurality of pixels including:
 a first subset of pixels positioned over the hole in the opaque masking layer; and 
 a second subset of pixels positioned remote from the hole in the opaque masking layer; and 
 
 the color temperature is determined based on ambient light that is received while the first subset of pixels are not illuminated. 
 
     
     
       11. The mobile phone of  claim 8 , wherein:
 the display stack comprises electrodes extending over an active area of the display stack; 
 the hole in the opaque masking layer is positioned in the active area of the display stack; 
 a pair of the electrodes is positioned in an overlapping pattern in an area over the hole in the opaque masking layer; and 
 the pair of the electrodes is positioned in a non-overlapping pattern in an area remote from the hole in the opaque masking layer. 
 
     
     
       12. The mobile phone of  claim 8 , wherein the mobile phone is further configured to change a display parameter of the display stack based at least in part on the color temperature. 
     
     
       13. The mobile phone of  claim 12 , wherein the display parameter is a color temperature of the graphical output. 
     
     
       14. The mobile phone of  claim 8 , wherein the light sensor module further comprises:
 a light sensing element; and 
 a light diffuser positioned below the opaque masking layer and above the light sensing element. 
 
     
     
       15. A method of determining an ambient light measurement with a portable electronic device, comprising:
 displaying a graphical output with a display stack positioned below a front cover of the portable electronic device, the graphical output visible through the front cover; and 
 determining an ambient light value of ambient light external to the portable electronic device, comprising:
 sensing light with a light sensor module positioned below the display stack, the sensing performed at a time when the graphical output is visible and a portion of the display stack covering the light sensor module is not emitting light; 
 producing an output corresponding to the sensed light; and 
 determining the ambient light value based at least in part on the output from the light sensor module. 
 
 
     
     
       16. The method of  claim 15 , wherein:
 the display stack comprises an opaque masking layer defining a hole; 
 the light sensor module is positioned below the opaque masking layer and senses the light through the hole in the opaque masking layer; and 
 the output corresponding to the sensed light includes:
 a first component resulting from the ambient light received through the front cover and through the portion of the display stack covering the hole in the opaque masking layer; and 
 a second component resulting from light emitted by a portion of the display stack not covering the hole in the opaque masking layer. 
 
 
     
     
       17. The method of  claim 16 , wherein the operation of determining the ambient light value comprises at least partially subtracting the second component from the output. 
     
     
       18. The method of  claim 17 , wherein the second component corresponds to a color emitted by the portion of the display stack not covering the hole in the opaque masking layer. 
     
     
       19. The method of  claim 17 , wherein the second component corresponds to a brightness of the portion of the display stack not covering the hole in the opaque masking layer. 
     
     
       20. The method of  claim 15 , wherein:
 the display stack defines a plurality of pixels configured to be selectively illuminated to produce the graphical output; 
 while the graphical output is displayed, a blanking interval defined by a region of non-illuminated pixels moves along an active area of the display stack; and 
 the ambient light value is determined based on the light that is sensed while the blanking interval is above the light sensor module.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a nonprovisional patent application of and claims the benefit of U.S. Provisional Patent Application No. 63/155,693, filed Mar. 2, 2021 and titled “Handheld Electronic Device,” U.S. Provisional Patent Application No. 63/170,327, filed Apr. 2, 2021 and titled “Handheld Electronic Device,” and U.S. Provisional Patent Application No. 63/208,477, filed Jun. 8, 2021 and titled “Handheld Electronic Device,” the disclosures of which are hereby incorporated herein by reference in their entireties. 
    
    
     FIELD 
     The subject matter of this disclosure relates generally to handheld electronic devices, and more particularly, to mobile phones. 
     BACKGROUND 
     Modern consumer electronic devices take many shapes and forms, and have numerous uses and functions. Smartphones, for example, provide various ways for users to interact with other people that extend beyond telephone communications. Such devices may include numerous systems to facilitate such interactions. For example, a smartphone may include a touch-sensitive display for providing graphical outputs and for accepting touch inputs, wireless communications systems for connecting with other devices to send and receive voice and data content, cameras for capturing photographs and videos, and so forth. However, integrating these subsystems into a compact and reliable product that is able to withstand daily use presents a variety of technical challenges. The systems and techniques described herein may address many of these challenges while providing a device that offers a wide range of functionality. 
     SUMMARY 
     A portable electronic device includes a housing, a front cover coupled to the housing and defining a front side of the portable electronic device, a display stack below the front cover and including a plurality of display layers configured to produce a graphical output in a display region of the display stack, the graphical output visible through the front cover, and a light sensor module positioned at least partially within the housing and coupled to the display stack in the display region. The light sensor module may be configured to receive ambient light passing through the front cover and through the plurality of display layers and, while a blanking interval is positioned over the light sensor module, produce an output corresponding to the received ambient light, the portable electronic device configured to determine an ambient light value based at least in part on the output from the light sensor module. The ambient light value may be a color temperature of the ambient light. The portable electronic device may be further configured to change a display parameter of the display stack based at least in part on the ambient light value. The blanking interval may be a vertical blanking interval. 
     The portable electronic device may further include a camera positioned in a front-facing sensor region of the front side of the portable electronic device and configured to capture images through the front cover, and the light sensor module may be proximate the front-facing sensor region. 
     At least one of the plurality of display layers may include electrodes, the electrodes arranged in a first pattern in an area above the light sensor module, and the electrodes arranged in a second pattern different from the first pattern in an area remote from the light sensor module. The first pattern may correspond to a first subset of the electrodes being layered on top of a second subset of the electrodes. 
     A mobile phone may include a housing, a transparent cover coupled to the housing, and a display stack at least partially within the housing and positioned below the transparent cover, the display stack including a plurality of display layers configured to produce a graphical output visible through the transparent cover and an opaque masking layer positioned below the plurality of display layers and defining a hole. The mobile phone may further include a light sensor module coupled to the display stack and configured to receive ambient light that passes through the transparent cover, the plurality of display layers, and the hole in the opaque masking layer, and is configured to produce an output corresponding to the received ambient light. The mobile phone may be configured to determine a color temperature of the ambient light based at least in part on the output from the light sensor module. An area of the hole in the opaque masking layer may be smaller than an area of a light sensing element of the light sensor module. The mobile phone may be further configured to change a display parameter of the display stack based at least in part on the color temperature. The display parameter may be a color temperature of the graphical output. The light sensor module may further include a light sensing element and a light diffuser positioned below the opaque masking layer and above the light sensing element. 
     The plurality of display layers may define a plurality of pixels configured to be selectively illuminated to produce the graphical output, the plurality of pixels including a first subset of pixels positioned over the hole in the opaque masking layer and a second subset of pixels positioned remote from the hole in the opaque masking layer. The color temperature may be determined based on ambient light that is received while the first subset of pixels are not illuminated. 
     The display stack may include electrodes extending over an active area of the display stack, the hole in the opaque masking layer may be positioned in the active area of the display stack, a pair of the electrodes may be positioned in an overlapping pattern in an area over the hole in the opaque masking layer, and the pair of the electrodes may be positioned in a non-overlapping pattern in an area remote from the hole in the opaque masking layer. 
     A method of determining an ambient light measurement with a portable electronic device includes displaying a graphical output with a display stack positioned below a front cover of the portable electronic device, the graphical output visible through the front cover and determining an ambient light value of ambient light external to the portable electronic device. Determining the ambient light value may include sensing light with a light sensor module positioned below the display stack, the sensing performed at a time when the graphical output is visible and a portion of the display stack covering the light sensor module is not emitting light, producing an output corresponding to the sensed light, and determining the ambient light value based at least in part on the output from the light sensor module. The display stack may define a plurality of pixels configured to be selectively illuminated to produce the graphical output, while the graphical output is displayed, a blanking interval defined by a region of non-illuminated pixels may move along an active area of the display stack, and the ambient light value may be determined based on the light that is sensed while the blanking interval is above the light sensor module. 
     The display stack may include an opaque masking layer defining a hole, the light sensor module may be positioned below the opaque masking layer and may sense the light through the hole in the opaque masking layer, and the output corresponding to the sensed light may include a first component resulting from the ambient light received through the front cover and through the portion of the display stack covering the hole in the opaque masking layer and a second component resulting from light emitted by a portion of the display stack not covering the hole in the opaque masking layer. The operation of determining the ambient light value may include at least partially subtracting the second component from the output. The second component may correspond to a color emitted by the portion of the display stack not covering the hole in the opaque masking layer. The second component may correspond to a brightness of the portion of the display stack not covering the hole in the opaque masking layer. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which: 
         FIGS.  1 A- 1 B  depict an example electronic device; 
         FIGS.  1 C- 1 D  depict another example electronic device; 
         FIG.  2    depicts an exploded view of an example electronic device; 
         FIG.  3    depicts an exploded view of an example electronic device; 
         FIGS.  4 A- 4 B  depict a portion of an example electronic device; 
         FIG.  4 C  depicts a partial exploded view of an example electronic device; 
         FIG.  5    depicts an example cover structure for a speaker port of an example electronic device; 
         FIGS.  6 A- 6 B  depict partial cross-sectional views of a speaker configuration for an example electronic device; 
         FIG.  6 C  depicts a partial cross-sectional view of another example speaker configuration for an example electronic device; 
         FIG.  7 A  depicts a partial cross-sectional view of a microphone configuration for an example electronic device; 
         FIG.  7 B  depicts a partial cross-sectional view of another microphone configuration for an example electronic device; 
         FIG.  7 C  depicts an exploded view of the microphone configuration of  FIG.  7 B ; 
         FIGS.  8 A- 8 C  depict partial views of example electronic devices, illustrating example speaker port configurations; 
         FIG.  9 A  depicts a partial view of an example front-facing sensor region of an example electronic device; 
         FIG.  9 B  depicts a partial cross-sectional view of an example device, illustrating a portion of a front-facing sensor region of the example electronic device; 
         FIG.  9 C  depicts a partial view of an example front-facing sensor region of another example electronic device; 
         FIGS.  9 D- 9 F  depict partial cross-sectional views of front-facing sensor regions of example electronic devices; 
         FIG.  9 G  depicts an example front-facing camera of an example electronic device; 
         FIG.  9 H  depicts an exploded view of a portion of a front-facing sensor region of an example electronic device; 
         FIGS.  10 A- 10 C  depict partial cross-sectional views of an example electronic device, illustrating an example combination flood illuminator and dot projector configuration; 
         FIG.  11 A  depicts a partial cross-sectional view of an example electronic device, illustrating an example ambient light sensor; 
         FIGS.  11 B- 11 C  depict a portion of an example electronic device, illustrating an operation of the example ambient light sensor; 
         FIGS.  12 A- 12 B  depict example electrode patterns on example electronic devices; 
         FIGS.  13 A- 13 C  depict partial cross-sectional views of example electronic devices, illustrating example display potting configurations; 
         FIG.  13 D  depicts a partial view of an example electronic device, illustrating an example display potting configuration; 
         FIG.  13 E  depicts a partial cross-sectional view of an example electronic device, illustrating an example display potting configuration; 
         FIG.  13 F  depicts a partial cross-sectional view of an example electronic device, illustrating an example cover configuration; 
         FIGS.  13 G- 13 L  depict partial cross-sectional views of example covers for electronic devices; 
         FIG.  13 M  depicts a partial cross-sectional view of an example electronic device, illustrating an example adhesive for attaching a display to a cover; 
         FIG.  13 N  depicts a partial cross-sectional view of an example electronic device, illustrating an example configuration for mounting a top module to a housing; 
         FIG.  14 A  depicts a partial view of an example electronic device; 
         FIGS.  14 B- 14 D  depict an example side-fired antenna for an electronic device; 
         FIG.  15    depicts example antenna feed and ground points for an electronic device; 
         FIG.  16 A  depicts a partial view of a housing member for an electronic device; 
         FIG.  16 B  depicts a partial cross-sectional view of a housing of an electronic device including the housing member of  FIG.  16 A ; 
         FIG.  16 C  depicts a partial view of a housing member for an electronic device; 
         FIG.  16 D  depicts a partial cross-sectional view of a housing of an electronic device including the housing member of  FIG.  16 C ; 
         FIG.  16 E  depicts a partial cross-sectional view of a housing of an electronic device including the housing members of  FIG.  16 A  and  FIG.  16 C ; 
         FIG.  17 A  depicts a portion of an electronic device illustrating an example arrangement of camera modules in an example electronic device; 
         FIGS.  17 B- 17 C  depict the camera modules of  FIG.  17 A ; 
         FIG.  17 D  depicts a portion of an example electronic device with camera modules removed; 
         FIGS.  17 E- 17 F  depict a spring member for use with camera modules for an electronic device; 
         FIG.  17 G  depicts a portion of an electronic device, illustrating an example arrangement of components in the device; 
         FIG.  17 H  depicts a partial cross-sectional view of an example mounting configuration for a shroud of an electronic device; 
         FIG.  17 I  depicts a partial cross-sectional view of an example mounting configuration for attaching components to an electronic device; 
         FIG.  18 A  depicts a partial cross-sectional view of an example electronic device, illustrating an example depth sensor configuration; 
         FIG.  18 B  depicts a partial cross-sectional view of an example electronic device, illustrating another example depth sensor configuration; 
         FIG.  18 C  depicts a partial cross-sectional view of an example electronic device, illustrating another example depth sensor configuration; 
         FIG.  19 A  depicts a partial cross-sectional view of an example electronic device, illustrating an example rear camera configuration; 
         FIG.  19 B  depicts a partial cross-sectional view of an example electronic device, illustrating an example arrangement of a window trim in a rear cover of the electronic device; 
         FIG.  19 C  depicts a partial cross-sectional view of an example electronic device, illustrating another example arrangement of a window trim in a rear cover of the electronic device; 
         FIG.  20 A  depicts a flash module of an example electronic device; 
         FIG.  20 B  depicts a partial cross-sectional view of the flash module of  FIG.  20 A ; 
         FIG.  20 C  depicts a partial cross-sectional view of another example flash module; 
         FIGS.  20 D- 20 G  depict partial cross-sectional views of example flash modules for electronic devices; 
         FIG.  21 A  depicts an example logic board for an electronic device; 
         FIG.  21 B  depicts a partial cross-sectional view of the logic board of  FIG.  21 A ; 
         FIG.  21 C  depicts a partial cross-sectional view of another example logic board; 
         FIG.  21 D  depicts a partial cross-sectional view of another example logic board; 
         FIG.  21 E  depicts a partial view of an example fastening configuration for a logic board; 
         FIG.  21 F  depicts a partial cross-sectional view of the logic board of  FIG.  21 A , illustrating the fastening configuration shown in  FIG.  21 E ; 
         FIGS.  21 G- 21 I  depict another example logic board; 
         FIG.  22 A  depicts a portion of an electronic device with a battery shown detached from a housing; 
         FIG.  22 B  depicts an example adhesive configuration for attaching a battery to a housing of an electronic device; 
         FIG.  22 C  depicts a partial cross-sectional view of an adhesive stack for attaching a battery to a housing of an electronic device; 
         FIGS.  22 D- 22 F  depict example adhesive configurations for attaching a battery to a housing of an electronic device; 
         FIGS.  22 G- 22 H  depict example battery mounting structures for attaching a battery to an electronic device; 
         FIG.  23 A  depicts a partial view of an electronic device, illustrating an example arrangement of a sensor module relative to a housing member; 
         FIGS.  23 B- 23 G  depict example configurations of sensor modules having multiple sensing components sharing common volumes; and 
         FIG.  24    depicts a schematic diagram of an example electronic device. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the described embodiments as defined by the appended claims. 
     Mobile phones as described herein may include complex, sophisticated components and systems that facilitate a multitude of functions. For example, mobile phones according to the instant disclosure may include touch- and/or force-sensitive displays, numerous cameras (including both front- and rear-facing cameras), GPS systems, haptic actuators, wireless charging systems, and all requisite computing components and software to operate these (and other) systems and otherwise provide the functionality of the mobile phones. 
       FIGS.  1 A and  1 B  show an example electronic device  100  embodied as a mobile phone.  FIG.  1 A  illustrates a front of the device  100 , while  FIG.  1 B  illustrates a back side of the device. While the device  100  is a mobile phone, the concepts presented herein may apply to any appropriate electronic devices, including portable electronic devices, wearable devices (e.g., watches), laptop computers, handheld gaming devices, tablet computers, computing peripherals (e.g., mice, touchpads, keyboards), or any other device. Accordingly, any reference to an “electronic device” encompasses any and all of the foregoing. 
     The electronic device  100  includes a cover  102  (e.g., a front cover), such as a glass, glass-ceramic, ceramic, plastic, sapphire, or other substantially transparent material, component, or assembly, attached to a housing  104  (which may include a housing structure defined by one or more housing members). The cover  102  may be positioned over a display  103 . The cover  102  may be formed from glass (e.g., a chemically strengthened glass), sapphire, ceramic, glass-ceramic, plastic, or another suitable material. The cover  102  may be formed as a monolithic or unitary sheet. The cover  102  may also be formed as a composite of multiple layers of different materials, coatings, and other elements. 
     The display  103  may be at least partially positioned within the interior volume of the housing  104 . The display  103  may be coupled to the cover  102 , such as via an adhesive or other coupling scheme. The display  103  may include a liquid-crystal display (LCD), a light-emitting diode, an organic light-emitting diode (OLED) display, an active layer organic light emitting diode (AMOLED) display, an organic electroluminescent (EL) display, an electrophoretic ink display, or the like. The display  103  may be configured to display graphical outputs, such as graphical user interfaces, that the user may view and interact with. The device  100  may also include an ambient light sensor that can determine properties of the ambient light conditions surrounding the device  100 . Example ambient light sensors are described herein with respect to  FIGS.  11 A- 11 C . The device  100  may use information from the ambient light sensor to change, modify, adjust, or otherwise control the display  103  (e.g., by changing a hue, brightness, saturation, or other optical aspect of the display based on information from the ambient light sensor). 
     The display  103  may include or be associated with one or more touch- and/or force-sensing systems. In some cases, components of the touch- and/or force-sensing systems are integrated with the display stack. For example, electrode layers of a touch and/or force sensor may be provided in a stack that includes display components (and is optionally attached to or at least viewable through the cover  102 ). The touch- and/or force-sensing systems may use any suitable type of sensing technology, including capacitive sensors, resistive sensors, surface acoustic wave sensors, piezoelectric sensors, strain gauges, or the like. The outer or exterior surface of the cover  102  may define an input surface (e.g., a touch- and/or force-sensitive input surface) of the device. While both touch- and force-sensing systems may be included, in some cases the device  100  includes a touch-sensing system and does not include a force-sensing system. 
     The device  100  may also include a front-facing camera  106 . The front-facing camera  106  may be positioned below or otherwise covered and/or protected by the cover  102 . The front-facing camera  106  may have any suitable operational parameters. For example, the front-facing camera  106  may include a 12 megapixel sensor (with 1 micron pixel size), and an 80-90° field of view. The front-facing camera  106  may have fixed focus optical elements with an aperture number of f/2.2. Other types of cameras may also be used for the front-facing camera  106 , such as auto-focus cameras. 
     The front-facing camera  106  may be positioned in a front-facing sensor region  111 . The front-facing sensor region  111  may be positioned in a notch-like area of the front of the device  100 . In some cases, as described herein, the front-facing sensor region  111  may be positioned in or defined by a recessed area of the display  103  (e.g., an area that is not occupied by the display or by a visually active portion of the display). In some cases, the front-facing sensor region  111  includes a mask or other visually opaque component or treatment that defines openings for the sensors. In some cases, one or more of the sensors or other devices in the front-facing sensor region  111  (e.g., the front-facing camera  106 ) are aligned with a hole formed through one or more layers of the display  103  to provide optical access to the sensor. The front-facing sensor region  111  may include components such as a flood illuminator module, a proximity sensor module, an infrared light projector, an infrared image capture device, and the front-facing camera  106 . 
     The device  100  may also include one or more buttons (e.g., button  120 , and buttons  116  in  FIG.  1 B ), switches (e.g., switch  118 ,  FIG.  1 B ), and/or other physical input systems. Such input systems may be used to control power states (e.g., the button  120 ), change speaker volume (e.g., the buttons  116 ), switch between “ring” and “silent” modes, and the like (e.g., the switch  118 ). 
     The device  100  may also include a speaker port  110  to provide audio output to a user, such as to a user&#39;s ear during voice calls. The speaker port  110  may also be referred to as a receiver, receiver port, or an earpiece in the context of a mobile phone. The device  100  may also include a charging port  112  (e.g., for receiving a connector of a power cable for providing power to the device  100  and charging the battery of the device  100 ). The device  100  may also include audio openings  114 . The audio openings  114  may allow sound output from an internal speaker system (e.g., the speaker system  224 ,  FIG.  2   ) to exit the housing  104 . The device  100  may also include one or more microphones. In some cases, a microphone within the housing  104  may be acoustically coupled to the surrounding environment through an audio opening  114 . 
     The housing  104  may be a multi-piece housing. For example, the housing  104  may be formed from multiple housing members  124 ,  125 ,  126 ,  127 ,  128 , and  130 , which are structurally coupled together via one or more joint structures  122  (e.g.,  122 - 1 - 122 - 6 ). Together, the housing members  124 ,  125 ,  126 ,  127 ,  128 , and  130  and the joint structures  122  may define a band-like housing structure that defines four side walls (and thus four exterior side surfaces) of the device  100 . Thus, both the housing members and the joint structures define portions of the exterior side surfaces of the device  100 . 
     The housing members  124 ,  125 ,  126 ,  127 ,  128 , and  130  may be formed of a conductive material (e.g., a metal such as aluminum, stainless steel, or the like), and the joint structures  122  may be formed of one or more polymer materials (e.g., glass-reinforced polymer). The joint structures  122  may include two or more molded elements, which may be formed of different materials. For example, an inner molded element may be formed of a first material (e.g., a polymer material), and an outer molded element may be formed of a second material that is different from the first (e.g., a different polymer material). The materials may have different properties, which may be selected based on the different functions of the inner and outer molded elements. For example, the inner molded element may be configured to make the main structural connection between housing members, and may have a higher mechanical strength and/or toughness than the outer molded element. On the other hand, the outer molded element may be configured to have a particular appearance, surface finish, chemical resistance, water-sealing function, or the like, and its composition may be selected to prioritize those functions over mechanical strength. 
     In some cases, one or more of the housing members  124 ,  125 ,  126 ,  127 ,  128 , and  130  (or portions thereof) are configured to operate as antennas (e.g., members that are configured to transmit and/or receive electromagnetic waves to facilitate wireless communications with other computers and/or devices). To facilitate the use of the housing members as antennas, feed and ground lines may be conductively coupled to the housing members to couple the housing members to other antennas and/or communication circuitry.  FIG.  11   , described in more detail below, depicts example antenna feed and ground lines for an example device. Further, the joint structures  122  may be substantially non-conductive to provide suitable separation and/or electrical isolation between the housing members (which may be used to tune the radiating portions, reduce capacitive coupling between radiating portions and other structures, and the like). In addition to the housing members  124 ,  125 ,  126 ,  127 ,  128 , and  130 , the device  100  may also include various internal antenna elements that are configured to transmit and receive wireless communication signals through various regions of the housing  104 . As shown in  FIG.  1 A , the device  100  may include an antenna window  129  that allows for the passage of radio-frequency communication signals through a corresponding region of the housing  104 . 
     The joint structures  122  may be mechanically interlocked with the housing members to structurally couple the housing members and form a structural housing assembly. Further details about the joint structures  122  and their mechanical integration with the housing members are provided herein. 
     The exterior surfaces of the housing members  124 ,  125 ,  126 ,  127 ,  128 , and  130  may have substantially a same color, surface texture, and overall appearance as the exterior surfaces of the joint structures  122 . In some cases, the exterior surfaces of the housing members  124 ,  125 ,  126 ,  127 ,  128 , and  130  and the exterior surfaces of the joint structures  122  are subjected to at least one common finishing procedure, such as abrasive-blasting, machining, polishing, grinding, or the like. Accordingly, the exterior surfaces of the housing members and the joint structures may have a same or similar surface finish (e.g., surface texture, roughness, pattern, etc.). In some cases, the exterior surfaces of the housing members and the joint structures may be subjected to a two-stage blasting process to produce the target surface finish. 
       FIG.  1 A  also includes an example coordinate system  101  that may define directions with reference to the device  100  (or other electronic devices described herein). The coordinate system  101  defines a positive x direction, a positive y direction, and a positive z direction. Unless stated otherwise, references herein to a positive x, positive y, or positive z direction will be understood to refer generally to the coordinate system  101  and its relationship to the device  100  in  FIG.  1 A . Negative x, y, and z directions will be understood to be opposite to the positive x, y, and z directions shown in the coordinate system in  FIG.  1 A . 
       FIG.  1 B  illustrates a back side of the device  100 . The device  100  may include a back or rear cover  132  coupled to the housing  104  and defining at least a portion of the exterior rear surface of the device  100 . The rear cover  132  may include a substrate formed of glass, though other suitable materials may alternatively be used (e.g., plastic, sapphire, ceramic, glass-ceramic, etc.). The rear cover  132  may include one or more decorative layers on the exterior or interior surface of the substrate. For example, one or more opaque layers may be applied to the interior surface of the substrate (or otherwise positioned along the interior surface of the substrate) to provide a particular appearance to the back side of the device  100 . The opaque layer(s) may include a sheet, ink, dye, or combinations of these (or other) layers, materials, or the like. In some cases the opaque layer(s) have a color that substantially matches a color of the housing  104  (e.g., the exterior surfaces of the housing members and the joint structures). The device  100  may include a wireless charging system, whereby the device  100  can be powered and/or its battery recharged by an inductive (or other electromagnetic) coupling between a charger and a wireless charging system within the device  100 . In such cases, the rear cover  132  may be formed of a material that allows and/or facilitates the wireless coupling between the charger and the wireless charging system (e.g., glass). 
     The device  100  may also include a sensor array  134 , which may include various types of sensors, including one or more rear-facing cameras, depth sensing devices, flashes, microphones, and the like. The sensor array  134  may be at least partially defined by a protrusion  137  that extends from the rear of the device  100 . The protrusion  137  may define a portion of the rear exterior surface of the device  100 , and may at least partially define a raised sensor array region of the sensor array  134 . In some cases, the protrusion  137  may be formed by attaching a piece of material (e.g., glass) to another piece of material (e.g., glass). In other cases, the rear cover  132  may include a monolithic structure, and the protrusion  137  may be part of the monolithic structure. For example, the rear cover  132  may include a monolithic glass structure (or glass ceramic structure) that defines the protrusion  137  as well as the surrounding area. In such cases, the protrusion  137  may be an area of increased thickness of the monolithic structure, or it may be molded into a substantially uniform thickness monolithic structure (e.g., and may correspond to a recessed region along an interior side of the monolithic structure). 
     The device may also include, as part of the sensor array, one or more rear-facing devices, which may include an ambient-light sensor (ALS), a microphone, and/or a depth sensing device that is configured to estimate a distance between the device  100  and a separate object or target. The sensor array  134  may also include multiple cameras, such as a first camera  138  and a second camera  139 . The first camera  138  may include a super-wide camera having a 12 megapixel sensor and a wide field of view (e.g., 120° FOV) optical stack with an aperture number of f/2.4; the second camera  139  may include a wide view camera having a 12 megapixel sensor and an aperture number of f/1.6. In some cases, the sensor array  134  may include a telephoto lens having a 12 megapixel sensor with a 3× optical zoom optical stack having an aperture number ranging from f/2.0 to f/2.8 (e.g., in addition to the first and second cameras  138 ,  139 , or in place of one of the first or second cameras). One or more of the cameras (e.g., cameras  138 ,  139 ) of the sensor array  134  may also include optical image stabilization, whereby the lens is dynamically moved relative to a fixed structure within the device  100  to reduce the effects of “camera shake” on images captured by the camera. The camera(s) may also perform optical image stabilization by moving the image sensor relative to a fixed lens or optical assembly. One or more of the cameras may include autofocus functionality, in which one or more lens elements (and/or sensors) are movable to focus an image on a sensor. 
     As shown in  FIG.  1 B , the cameras of the sensor array  134  may be positioned diagonally with respect to the protrusion  137  (e.g., the raised sensor array). For example, a first hole may extend through the rear cover  132  at a location proximate a first corner region of the sensor array  134 , and the first camera  138  may be positioned at least partially in the first hole, and a second hole may extend through the rear cover  132  at a location proximate a second corner region diagonal from the first corner region of the sensor array  134 , and the second camera  139  may be positioned at least partially in the second hole. Thus, the first and second holes, and therefore the first and second cameras, may be positioned along a diagonal path from the first corner to the second corner of the sensor array  134 . 
     The second camera  139  may have an image sensor with a pixel size between about 1.5 microns and about 2.0 microns, and the first camera  138  may have an image sensor with a pixel size between about 0.8 microns and about 1.4 microns. If a camera with a telephoto lens is provided, it may have an image sensor with a pixel size between about 0.8 microns and about 1.4 microns. 
     The sensor array  134 , along with associated processors and software, may provide several image-capture features. For example, the sensor array  134  may be configured to capture full-resolution video clips of a certain duration each time a user captures a still image. As used herein, capturing full-resolution images (e.g., video images or still images) may refer to capturing images using all or substantially all of the pixels of an image sensor, or otherwise capturing images using the maximum resolution of the camera (regardless of whether the maximum resolution is limited by the hardware or software). 
     The captured video clips may be associated with the still image. In some cases, users may be able to select individual frames from the video clip as the representative still image associated with the video clip. In this way, when the user takes a snapshot of a scene, the camera will actually record a short video clip (e.g., 1 second, 2 seconds, or the like), and the user can select the exact frame from the video to use as the captured still image (in addition to simply viewing the video clip as a video). 
     The cameras of the sensor array  134  may also have or provide a high-dynamic-range (HDR) mode, in which the camera captures images having a dynamic range of luminosity that is greater than what is captured when the camera is not in the HDR mode. In some cases, the sensor array  134  automatically determines whether to capture images in an HDR or non-HDR mode. Such determination may be based on various factors, such as the ambient light of the scene, detected ranges of luminosity, tone, or other optical parameters in the scene, or the like. HDR images may be produced by capturing multiple images, each using different exposure or other image-capture parameters, and producing a composite image from the multiple captured images. 
     The sensor array  134  may also include or be configured to operate in an object detection mode, in which a user can select (and/or the device  100  can automatically identify) objects within a scene to facilitate those objects being processed, displayed, or captured differently than other parts of the scene. For example, a user may select (or the device  100  may automatically identify) a person&#39;s face in a scene, and the device  100  may focus on the person&#39;s face while selectively blurring the portions of the scene other than the person&#39;s face. Notably, features such as the HDR mode and the object detection mode may be provided with a single camera (e.g., a single lens and sensor). 
     The sensor array may include a flash  136  that is configured to illuminate a scene to facilitate capturing images with the sensor array  134 . The flash  136  may include one or more light sources, such as one or more light emitting diodes (e.g., 1, 2, 3, 4, or more LEDs). The flash  136 , in conjunction with the sensor array  134  or other systems of the device  100 , may adjust the color temperature of the light emitted by the light sources in order to match or otherwise adapt to a color temperature within a scene being captured. The device  100  may also be configured to operate the flash  136  and the shutter of the sensor array  134  (e.g., the shutter of one or more of the cameras  138 ,  139 ) to avoid consequences of flash “flicker.” For example, the device  100  may avoid capturing exposures during moments where the flash  136  is at a period of no or low illumination (e.g., which may be caused by discontinuous or pulsed operation of the LEDs). 
     The sensor array  134  may also include a microphone  135 . The microphone  135  may be acoustically coupled to the exterior environment through a hole defined in the rear cover of the device  100  (e.g., through the portion of the rear cover that defines the protrusion  137 ). 
       FIGS.  1 C and  1 D  show another example electronic device  140  embodied as a mobile phone. The electronic device  140  may have many of the same or similar outward-facing components as the electronic device  100 . Accordingly, descriptions and details of such components from  FIGS.  1 A- 1 B  (e.g., displays, buttons, switches, housings, covers, charging ports, joint structures, etc.) apply equally to the corresponding components shown in  FIGS.  1 C and  1 D . 
     While the device  100  in  FIG.  1 B  is shown as including a sensor array  134  with two cameras, the device  140  as shown in  FIG.  1 D  includes a sensor array  141  that includes three cameras (as shown, for example, in  FIG.  3   , described herein). The sensor array  141  may be in a sensor array region that is defined by a protrusion  151  in a rear cover of the device  140 . The protrusion  151  may have the same or similar construction as the protrusion  137  in  FIG.  1 B . 
     A first camera  142  may include a 12 megapixel sensor and a telephoto lens with a 3× optical zoom and an aperture number of f/2.8; a second camera  144  may include a 12 megapixel sensor and a wide angle lens having an aperture number of f/1.5; and a third camera  146  may include a 12 megapixel sensor and a super-wide camera with a wide field of view (e.g., 120° FOV) and an aperture number of f/1.8. One or more of the cameras of the sensor array  141  may also include optical image stabilization, whereby the lens is dynamically moved relative to a fixed structure within the device  100  to reduce the effects of “camera shake” on images captured by the camera. The camera(s) may also perform optical image stabilization by moving the image sensor relative to a fixed lens or optical assembly. 
     The first camera  142  may include an image sensor with a pixel size between about 0.8 microns and about 1.4 microns. The second camera  144  may include an image sensor with a pixel size between about 1.6 microns and about 2.3 microns. The third camera  146  may include an image sensor with a pixel size between about 0.8 microns and about 1.4 microns. 
     For example, a wide view camera having a 12 megapixel sensor and an aperture number of f/1.6 may have an image sensor with a pixel size between about 1.5 microns and about 2.0 microns; a super-wide camera having a 12 megapixel sensor and a wide field of view (e.g., 120° FOV) optical stack with an aperture number of f/2.4 may have an image sensor with a pixel size between about 0.8 microns and about 1.4 microns; and a telephoto lens having a 12 megapixel sensor with a 3× optical zoom optical stack having an aperture number ranging from f/2.0 to f/2.8 may have an image sensor with a pixel size between about 0.8 microns and about 1.4 microns. One or more of the cameras may include autofocus functionality, in which one or more lens elements (and/or sensors) are movable to focus an image on a sensor. 
     The sensor array  141  may also include a depth sensing device  149  that is configured to estimate a distance between the device and a separate object or target. The depth sensing device  149  may estimate a distance between the device and a separate object or target using lasers and time-of-flight calculations, or using other types of depth sensing components or techniques. 
     The device  140  may also include a flash  148  that is configured to illuminate a scene to facilitate capturing images with the cameras of the sensor array  141 . The flash  148  is configured to illuminate a scene to facilitate capturing images with the sensor array  141 . The flash  148  may include one or more light sources, such as one or more light emitting diodes (e.g., 1, 2, 3, 4, or more LEDs). 
     The sensor array  141  may also include a microphone  150 . The microphone  150  may be acoustically coupled to the exterior environment through a hole defined in the rear cover of the device  140  (e.g., through the portion of the rear cover that defines the protrusion  151 ). 
     Other details about the sensor array, the individual cameras of the sensor array, and/or the flash described with respect to the device  100  may be applicable to the sensor array, the individual cameras, and/or the flash of the device  140 , and such details will not be repeated here to avoid redundancy. 
       FIG.  2    depicts an exploded view of an example electronic device. In particular,  FIG.  2    depicts an exploded view of a device  200 , showing various components of the device  200  and example arrangements and configurations of the components. The description of the various components and elements of device  100  of  FIGS.  1 A and  1 B  may also be applicable to the device  200  depicted in  FIG.  2   . A redundant description of some of the components is not repeated herein for clarity. 
     As shown in  FIG.  2   , the device  200  includes a cover  202  (e.g., a front cover), which may be formed of glass, ceramic, or other transparent substrate. In this example, the cover  202  may be formed from a glass or glass-ceramic material. A glass-ceramic material may include both amorphous and crystalline or non-amorphous phases of one or more materials and may be formulated to improve strength or other properties of the cover  202 . In some cases, the cover  202  may include a sheet of chemically strengthened glass or glass-ceramic having one or more coatings including an anti-reflective (AR) coating, an oleophobic coating, or other type of coating or optical treatment. In some cases, the cover  202  includes a sheet of material that is less than 1 mm thick. In some cases, the sheet of material is less than 0.80 mm. In some cases, the sheet of material is approximately 0.60 mm or less. The cover  202  may be chemically strengthened using an ion exchange process to form a compressive stress layer along exterior surfaces of the cover  202 . 
     The cover  202  extends over a substantial entirety of the front surface of the device and may be positioned within an opening defined by the housing  210 . As described in more detail below, the edges or sides of the cover  202  may be surrounded by a protective flange or lip of the housing  210  without an interstitial component between the edges of the cover  202  and the respective flanges of the housing  210 . This configuration may allow an impact or force applied to the housing  210  to be transferred to the cover  202  without directly transferring shear stress through the display  203  or frame  204 . 
     As shown in  FIG.  2   , the display  203  is attached to an internal surface of the cover  202 . The display  203  may include an edge-to-edge organic light emitting diode (OLED) display that measures 13.7 cm (5.4 inches) corner-to-corner. The perimeter or non-active area of the display  203  may be reduced to allow for very thin device borders around the active area of the display  203 . In some cases, the display  203  allows for border regions of 1.5 mm or less. In some cases, the display  203  allows for border regions of 1 mm or less. In one example implementation, the border region is approximately 0.9 mm. The display  203  may have a relatively high pixel density of approximately 450 pixels per inch (PPI) or greater. In some cases, the display  203  has a pixel density of approximately 475 PPI. The display  203  may have an integrated (on-cell) touch-sensing system. For example, an array of electrodes that are integrated into the OLED display may be time and/or frequency multiplexed in order to provide both display and touch-sensing functionality. The electrodes may be configured to detect a location of a touch, a gesture input, multi-touch input, or other types of touch input along the external surface of the cover  202 . In some cases, the display  203  includes another type of display element, such as a liquid-crystal display (LCD) without an integrated touch-sensing system. That is, the device  200  may include one or more touch- and/or force-sensing layers that are positioned between the display  203  and the cover  202 . 
     The display  203 , also referred to as a display stack, may include always-on-display (AOD) functionality. For example, the display  203  may be configurable to allow designated regions or subsets of pixels to be displayed when the device  200  is powered on such that graphical content is visible to the user even when the device  200  is in a low-power or sleep mode. This may allow the time, date, battery status, recent notifications, and other graphical content to be displayed in a lower-power or sleep mode. This graphical content may be referred to as persistent or always-on graphical output. While some battery power may be consumed when displaying persistent or always-on graphical output, the power consumption is typically less than during normal or full-power operation of the display  203 . This functionality may be enabled by only operating a subset of the display pixels and/or at a reduced resolution in order to reduce power consumption by the display  203 . 
     As shown in  FIG.  2   , the device  200  may also include a frame member  204 , also referred to simply as a frame  204 , that is positioned below the cover  202  and that extends around at least an outer periphery of the display  203 . A perimeter of the frame  204  may be attached to a lower or inner surface of the cover  202 . A portion of the frame  204  may extend below the display  203  and may attach the cover  202  to the housing  210 . Because the display  203  is attached to a lower or inner surface of the cover  202 , the frame  204  may also be described as attaching both the display  203  and the cover  202  to the housing  210 . The frame  204  may be formed of a polymer material, metal material, or combination of polymer and metal materials. The frame  204  may support elements of the display stack, provide anchor points for flexible circuits, and/or be used to mount other components and device elements. In some cases, the frame  204  includes one or more metal or conductive elements that provide shielding between device components, such as between the display stack (including display components and touch sensor components) and other components like the haptic actuator  222 , the speaker system  224 , and the like. 
     The cover  202 , display stack  203 , and frame member  204  may be part of a top module  201  of the device  200 . The top module  201  may be assembled as a subassembly, which may then be attached to a housing member. For example, as described herein, the display  203  may be attached to the cover  202  (e.g., via a transparent adhesive), and the frame member  204  may be attached (e.g., via adhesive) to the cover around a periphery of the display stack  203 . The top module  201  may then be attached to a housing member of the device  200  by mounting and adhering the frame member  204  to a ledge defined by the housing member. 
     The device  200  also includes a speaker module  250  that is configured to output sound via a speaker port. The speaker port may be positioned in and/or at least partially defined by a recess  251  of the cover  202 . As described herein, a trim piece may be positioned at least partially in the recess  251  to facilitate the output of sound while also inhibiting the ingress of debris, liquid, or other materials or contaminants into the device  200 . Output from the speaker module  250  may pass through an acoustic path defined at least in part by the speaker module  250  itself, and the trim piece. In some cases, part of the acoustic path (e.g., between the speaker module  250  and the trim piece) is defined by the housing  210  and/or a molded material that is coupled to the housing  210 . For example, a molded material (e.g., a fiber-reinforced polymer) may be molded against a metal portion of the housing  210  (e.g., the housing member  213 , described herein). The molded material may also form one or more joint structures that also structurally join housing members together (e.g., the joint structures  218 ). A passage (e.g., a tube-like tunnel) may be defined through the molded material to acoustically couple the speaker module  250  to the trim piece and/or the recess  251  more generally, thereby directing sound from the speaker module  250  to the exterior of the device  200 . In some cases, a portion of the passage that extends through the molded material is defined by a housing member itself, as described herein with reference to  FIGS.  6 A- 6 B . 
     As shown in  FIG.  2   , the device  200  also includes one or more cameras, light emitters, and/or sensing elements that are configured to transmit signals, receive signals, or otherwise operate along the front surface of the device. In this example, the device  200  includes a front camera  206  that includes a high-resolution camera sensor. The front camera  206  may have a 12 megapixel resolution sensor with optical elements that provide a fixed focus and an 85° field of view. The device  200  also includes a facial recognition sensor  252  that includes an infrared light projector and infrared light sensor that are configured to sense an array of depth points or regions along the face of the user. The array of depth points may be characterized as a unique signature or bio-identifier, which may be used to identify the user and unlock the device  200  or authorize functionality on the device  200  like the purchase of software apps or the use of payment functionality provided by the device  200 . 
     The device  200  may also include one or more other sensors or components. For example, the device  200  may include a front light illuminator element for providing a flash or illumination for the front camera  206 . The device  200  may also include an ambient light sensor (ALS) that is used to detect ambient light conditions for setting exposure aspects of the front camera  206  and/or for controlling the operation of the display. 
       FIG.  2    also illustrates one or more cameras, light emitters, and/or sensing elements that are configured to transmit signals, receive signals, or otherwise operate along the rear surface of the device. As depicted in  FIG.  2   , these elements may be part of a sensor array  260 . In this example, the sensor array  260  includes a first camera  261  having a 12 megapixel image sensor and a wide angle lens with an aperture number of f/1.6. The first camera  261  also includes a dual photodiode sensor having an APS+ sensor format. The sensor array  260  also includes a second camera  262  having a 12 megapixel image sensor and a super-wide angle lens (120° FOV) with an aperture number of f/2.4. The sensor array  260  also includes a light illuminator that may be used as a flash for photography or as an auxiliary light source (e.g., a flashlight). The sensor array  260  also features an integrated chassis design that minimizes space while providing the precision alignment required for multiple high-resolution cameras. In some cases, the sensor array  260  also includes a microphone, an ambient light sensor, a depth sensor, and/or other sensors that are adapted to sense along the rear surface of the device  200 . 
     As shown in  FIG.  2   , the cameras  261  and  262  may be aligned with camera covers  263  and  264 , respectively. The covers  263 ,  264  may be formed from a glass, glass-ceramic, or sapphire material and may provide a clear window through which the cameras  261 ,  262  are able to capture a photographic image. In other cases, the covers  263 ,  264  are optical lenses that filter, magnify, or otherwise condition light received by the respective camera  261 ,  262 . The other sensing or transmitting elements of the sensor array  260  may transmit and/or receive signals through a region of the rear cover  272  or through a separate cover that is coupled to the rear cover  272 . As shown in  FIG.  2   , the covers  263 ,  264  may extend beyond the exterior surface of the cover  272 , and may define a recess along the interior side of the cover  272 , such that the lens or other element of the cameras  261  and  262  can extend into the respective recesses. In this way, the device  200  may accommodate a larger lens or other elements of the cameras  261  and  262  than would be possible if the recess were not provided. 
     The device  200  also includes a battery  230 . The battery  230  provides electrical power to the device  200  and its various systems and components. The battery  230  may include a 4.45 V lithium ion battery that is encased in a foil or other enclosing element (e.g., a pouch). The battery  230  may be attached to the device  200  (e.g., to the chassis  219 ) with one or more adhesives and/or other attachment techniques. In one example, the battery  230  may be attached to the chassis  219 , or another structure of the device  200 , with a two-layer adhesive, where a first adhesive is adhered to the battery  230  and to a second adhesive, and the second adhesive is bonded to the first adhesive and to the chassis  219  (or other structure of the device  200 ). The first and second adhesives may have different properties, such as different stiffness (e.g., Young&#39;s modulus), different adhesive properties, or the like. For example, in some cases, the first adhesive is configured to adhere to the material of the battery  230  (e.g., with a bond strength above a threshold value), while the second adhesive is configured to adhere to the chassis  219  or other structure of the device (e.g., with a bond strength above the threshold value). In such cases, the first adhesive may not form a sufficiently strong bond with the chassis  219 , and the second adhesive may not form a sufficiently strong bond with the battery  230 , though the first and second adhesives may form a sufficiently strong bond with one another. Accordingly, by using the two different adhesives (e.g., in the layered configuration described) to ultimately secure the battery  230  to the chassis  219 , the overall strength and/or security of the attachment may be greater than if a single adhesive were used. 
     The battery  230  may be recharged via the charging port  232  (e.g., from a power cable plugged into the charging port  232  through a charging access opening  226 ), and/or via a wireless charging system  240 . The battery  230  may be coupled to the charging port  232  and/or the wireless charging system  240  via battery control circuitry that controls the power provided to the battery and the power provided by the battery to the device  200 . The battery  230  may include one or more lithium ion battery cells or any other suitable type of rechargeable battery element. 
     The charging system  240  may include a coil that inductively couples to an output or transmitting coil of a wireless charger. The coil may provide current to the device  200  to charge the battery  230  and/or power the device. In this example, the charging system  240  includes a coil assembly  242  that includes multiple wraps of a conductive wire or other conduit that is configured to produce a (charging) current in response to being placed in an inductive charging electromagnetic field produced by a separate wireless charging device or accessory. The coil assembly  242  also includes or is associated with an array of magnetic elements that are arranged in a circular or radial pattern. The magnetic elements may help to locate the device  200  with respect to a separate wireless charging device or other accessory. In some implementations, the array of magnets also help to radially locate, orient, or “clock” the device  200  with respect to the separate wireless charging device or other accessory. For example, the array of magnets may include multiple magnetic elements having alternating magnetic polarity that are arranged in a radial pattern. The magnetic elements may be arranged to provide a magnetic coupling to the separate charging device in a particular orientation or set of discrete orientations to help locate the device  200  with respect to the separate charging device or other accessory. This functionality may be described as self-aligning or self-locating wireless charging. As shown in  FIG.  2   , the device  200  also includes a magnetic fiducial  244  for helping to locate the separate wireless charging device or accessory. In one example, the magnetic fiducial  244  is adapted to magnetically couple to a cable or power cord of the separate wireless charging device or other accessory. By coupling to the cable or power cord, the rotational alignment of the device  200  and the separate wireless charging device or other accessory may be maintained with respect to an absolute or single position. Also, by magnetically coupling the cable or cord to the rear surface of the device  200 , the charging device or other accessory may be more securely coupled to the device  200 . 
     In some implementations, the wireless charging system  240  includes an antenna or other element that detects the presence of a charging device or other accessory. In some cases, the charging system includes a near-field communications (NFC) antenna that is adapted to receive and/or send wireless communications between the device  200  and the wireless charger or other accessory. In some cases, the device  200  is adapted to perform wireless communications to detect or sense the presence of the wireless charger or other accessory without using a dedicated NFC antenna. The communications may also include information regarding the status of the device, the amount of charge held by the battery  230 , and/or control signals to increase charging, decrease charging, start charging and/or stop charging for a wireless charging operation. 
     The device  200  may also include a speaker system  224 . The speaker system  224  may be positioned in the device  200  so that a respective port  235  is aligned with or otherwise proximate an audio output of the speaker system  224 . Accordingly, sound that is output by the speaker system  224  exits the housing  210  via the respective port  235 . The speaker system  224  may include a speaker positioned in a housing that defines a speaker volume (e.g., an empty space in front of or behind a speaker diaphragm). The speaker volume may be used to tune the audio output from the speaker and optionally mitigate destructive interference of the sound produced by the speaker. The speaker system  224  may include left and right speakers that are aligned with left and right ports  225 ,  235 , respectively, in order to produce stereo sound. 
     The device  200  may also include a haptic actuator  222 . The haptic actuator  222  may include a movable mass and an actuation system that is configured to move the mass to produce a haptic output. The actuation system may include one or more coils and one or more magnets (e.g., permanent and/or electromagnets) that interact to produce motion. The magnets may be or may include recycled magnetic material. As described herein, the haptic actuator  222  may have a profile or enclosure shape that facilitates physical integration with the battery  230  and other components of the device  200  in order to minimize space and/or maximize the size of the battery. 
     When the coil(s) are energized, the coil(s) may cause the mass to move, which results in a force being imparted on the device  200 . The motion of the mass may be configured to cause a vibration, pulse, tap, or other tactile output detectable via an exterior surface of the device  200 . The haptic actuator  222  may be configured to move the mass linearly, though other movements (e.g., rotational) are also contemplated. Other types of haptic actuators may be used instead of or in addition to the haptic actuator  222 . 
     The device  200  also includes a logic board  220  (also referred to herein as a circuit board assembly). The logic board  220  may include a substrate, and processors, memory, and other circuit elements coupled to the substrate. The logic board  220  may include multiple circuit substrates that are stacked and coupled together in order to maximize the area available for electronic components and circuitry in a compact form factor. The logic board  220  may include provisions for a subscriber identity module (SIM). The logic board  220  may include electrical contacts and/or a SIM tray assembly for receiving a physical SIM card and/or the logic board  220  may include provisions for an electronic SIM. The logic board  220  may be wholly or partially encapsulated to reduce the chance of damage due to ingress of water or other fluid. 
     The logic board  220  may also include wireless communications circuitry, which may be coupled to and/or otherwise use the housing members  211 ,  212 ,  213 ,  214 ,  215 , or  216  (or portions thereof) as radiating members to provide wireless communications. The logic board  220  may also include components such as accelerometers, gyroscopes, near-field communications circuitry and/or antennas, compasses, and the like. In some implementations, the logic board  220  may include a magnetometer that is adapted to detect and/or locate an accessory. For example, the magnetometer may be adapted to detect a magnetic (or non-magnetic) signal produced by an accessory of the device  200  or other device. The output of the magnetometer may include a direction output that may be used to display a directional indicia or other navigational guidance on the display  203  in order to guide the user toward a location of the accessory or other device. 
     The device  200  may also include one or more pressure transducers that may be operable to detect changes in external pressure in order to determine changes in altitude or height. The pressure sensors may be externally ported and/or positioned within a water-sealed internal volume of the housing  210 . The output of the pressure sensors may be used to track flights of stairs climbed, a location (e.g., a floor) of a multi-story structure, movement performed during an activity in order to estimate physical effort or calories burned, or other relative movement of the device  200 . 
     The logic board  220  may also include global position system (GPS) electronics that may be used to determine the location of the device  200  with respect to one or more satellites (e.g., a Global Navigation Satellite System (GNSS)) in order to estimate an absolution location of the device  200 . In some implementations, the GPS electronics are operable to utilize dual frequency bands. For example, the GPS electronics may use L1 (L1C), L2 (L2C), L5, L1+L5, and other GPS signal bands in order to estimate the location of the device  200 . 
     The housing  210  may also include a chassis  219 , which may be attached to the housing  210 . The chassis  219  may be formed of metal, and may act as a structural mounting point for components of the device  200 . The chassis  219  may define an opening that corresponds to the size of the coil assembly  242  of the wireless charging system  240 , such that the chassis  219  does not shield the wireless coil assembly  242  or otherwise negatively affect the inductive coupling between the coil of the charging system  240  and an external wireless charger or accessory. 
     As shown in  FIG.  2   , the housing may include a cover  272  (e.g., rear or back cover) that may define a substantial entirety of the rear surface of the device  200 . The cover  272  may be formed from a glass (or glass-ceramic) substrate having portions that are less than 1 mm thick. In some cases, the sheet substrate has portions that are less than 0.80 mm. In some cases, the glass substrate has portions that are approximately 0.60 mm or less. The cover  272  may have a uniform thickness or, in some cases, may have a thickened or raised portion that surrounds the camera covers  263 ,  264 . The cover  272  may be machined (e.g., ground) into a final shape before being polished and/or textured to provide the desired surface finish. The texture may be specially configured to provide a matte appearance while also being resistant to collecting a buildup of skin, lint, or other debris. A series of cosmetic layers may be formed along the inner surface of the cover  272  to provide a desired optical effect and final color of the device  200 . 
     Similar to as described above with respect to cover  202 , the cover  272  may be positioned at least partially within an opening defined in the housing  210 . Also similar to as described above with respect to cover  202 , the edges or sides of the cover  272  may be surrounded by a protective flange or lip of the housing  210  without an interstitial component between the edges of the cover  272  and the respective flanges of the housing  210 . The cover  272  is typically chemically strengthened using an ion exchange process to form a compressive stress layer along exterior surfaces of the cover  272 . 
     As described above, the housing  210  may include housing members  211 ,  212 ,  213 ,  214 ,  215 , and  216  structurally joined together via joint structures  218 . The joint structures  218  (e.g., the material of the joint structures) may extend over inner surfaces of the housing members. More particularly, a portion of the joint structures  218  may contact, cover, encapsulate, and/or engage with retention features of the housing members that extend from the inner surfaces of the housing members. 
     Housing members  211 ,  212 ,  213 ,  214 ,  215 , and  216  may also be referred to herein as housing segments and may be formed from aluminum, stainless steel, or other metal or metal alloy material. As described herein, the housing members  211 ,  212 ,  213 ,  214 ,  215 , and  216  may provide a robust and impact resistant sidewall for the device  200 . In the present example, the housing members  211 ,  212 ,  213 ,  214 ,  215 , and  216  define a flat sidewall that extends around the perimeter of the device  200 . The flat sidewall may include rounded or chamfered edges that define the upper and lower edges of the sidewall of the housing  210 . The housing members  211 ,  212 ,  213 ,  214 ,  215 , and  216  may each have a flange portion or lip that extends around and at least partially covers a respective side of the front and rear covers  202 ,  272 . There may be no interstitial material or elements between the flange portion or lip and the respective side surface of the front and rear covers  202 ,  272 . This may allow forces or impacts that are applied to the housing  210  to be transferred to the front and rear covers  202 ,  272  without affecting the display or other internal structural elements, which may improve the drop performance of the device  200 . 
     As shown in  FIG.  2   , the device  200  includes multiple antennas that may be adapted to conduct wireless communication using a 5G communication protocol. In particular, the device  200  may include a (side-fired) antenna array  282  that is configured to transmit and receive wireless communication signals through an antenna window  283  or waveguide formed along or otherwise integrated with the sidewall of the housing  210 . The side-fired antenna array  282  may be coupled to the logic board  220  via a flexible circuit element or other conductive connection, as described herein. The device  200  may also include a rear antenna module  284  that may include one or more (rear-fired) antenna arrays that may be configured to transmit and receive wireless communication signals through the cover  272 . The antenna module  284  may be attached to a back or bottom surface of the logic board  220 . 
     The antenna module  284  may include multiple antenna arrays. For example, the antenna module  284  may include one or more millimeter-wave antenna arrays. In the case where the antenna module  284  includes multiple millimeter-wave antenna arrays (each of which may include one or more radiating elements), the multiple millimeter-wave antenna arrays may be configured to operate according to a diversity scheme (e.g., spatial diversity, pattern diversity, polarization diversity, or the like). The antenna module  284  may also include one or more ultra-wideband antennas. 
     Each of the antenna arrays (e.g., the antenna array  284  and the millimeter-wave arrays of the antenna module  282 ) may be adapted to conduct millimeter wave 5G communications and may be adapted to use or be used with beam-forming or other techniques to adapt signal reception depending on the use case. The device  200  may also include multiple antennas for conducting multiple-in multiple-out (MIMO) wireless communications schemes, including 4G, 4G LTE, and/or 5G MIMO communication protocols. As described herein, one or more of the housing members  211 ,  212 ,  213 ,  214 ,  215 , and  216  may be adapted to operate as antennas for a MIMO wireless communication scheme (or other wireless communication scheme). 
       FIG.  3    depicts an exploded view of an example electronic device. In particular,  FIG.  3    depicts an exploded view of a device  300 , showing various components of the device  300  and example arrangements and configurations of the components. The description of the various components and elements of device  100  of  FIGS.  1 A and  1 B  may also be applicable to the device  300  depicted in  FIG.  3   . A redundant description of some of the components is not repeated herein for clarity. 
     As shown in  FIG.  3   , the device  300  includes a cover  302  (e.g., a front cover), which may be formed of glass, ceramic, or other transparent substrate. In this example, the cover  302  may be formed from a glass or glass-ceramic material. A glass-ceramic material may include both amorphous and crystalline or non-amorphous phases of one or more materials and may be formulated to improve strength or other properties of the cover  302 . In some cases, the cover  302  may include a sheet of chemically strengthened material having one or more coatings including an anti-reflective (AR) coating, an oleophobic coating, or other type of coating or optical treatment. In some cases, the cover  302  includes a sheet of material that is less than 1 mm thick. In some cases, the sheet of material is less than 0.80 mm. In some cases, the sheet of material is approximately 0.60 mm or less. The cover  302  may be chemically strengthened using an ion exchange process to form a compressive stress layer along exterior surfaces of the cover  302 . 
     The cover  302  extends over a substantial entirety of the front surface of the device and may be positioned within an opening defined by the housing  310 . As described in more detail below, the edges or sides of the cover  302  may be surrounded by a protective flange or lip of the housing  310  without an interstitial component between the edges of the cover  302  and the respective flanges of the housing  310 . This configuration may allow an impact or force applied to the housing  310  to be transferred to the cover  302  without directly transferring shear stress through the display  303  or frame  304 . 
     As shown in  FIG.  3   , the display  303  is coupled to an internal surface of the cover  302 . The display  303  may include an edge-to-edge organic light emitting diode (OLED) display that measures 16.97 cm (6.68 inches) corner-to-corner. The perimeter or non-active area of the display  303  may be reduced to allow for very thin device borders around the active area of the display  303 . In some cases, the display  303  allows for border regions of 1.5 mm or less. In some cases, the display  303  allows for border regions of 1 mm or less. In one example implementation, the border region is approximately 0.9 mm. The display  303  may have a relatively high pixel density of approximately 450 pixels per inch (PPI) or greater. In some cases, the display  303  has a pixel density of approximately 458 PPI. The display  303  may have an integrated (on-cell) touch-sensing system. For example, an array of electrodes that are integrated into the OLED display may be time and/or frequency multiplexed in order to provide both display and touch-sensing functionality. The electrodes may be configured to detect a location of a touch, a gesture input, multi-touch input, or other types of touch input along the external surface of the cover  302 . In some cases, the display  303  includes another type of display element, such as a liquid-crystal display (LCD) without an integrated touch-sensing system. That is, the device  300  may include one or more touch- and/or force-sensing layers that are positioned between the display  303  and the cover  302 . 
     The display  303  may include always-on-display (AOD) functionality. For example, the display  303  may be configurable to allow designated regions or subsets of pixels to be displayed when the device  300  is powered on such that graphical content is visible to the user even when the device  300  is in a low-power or sleep mode. This may allow the time, date, battery status, recent notifications, and other graphical content to be displayed in a lower-power or sleep mode. This graphical content may be referred to as persistent or always-on graphical output. While some battery power may be consumed when displaying persistent or always-on graphical output, the power consumption is typically less than during normal or full-power operation of the display  303 . This functionality may be enabled by only operating a subset of the display pixels and/or at a reduced resolution in order to reduce power consumption by the display  303 . 
     As shown in  FIG.  3   , the device  300  may also include a frame  304  that is positioned below the cover  302  and that extends around an outer periphery of the display  303 . A perimeter of the frame  304  may be attached to a lower or inner surface of the cover  302 . A portion of the frame  304  may extend below the display  303  and may attach the cover  302  to the housing  310 . Because the display  303  is attached to a lower or inner surface of the cover  302 , the frame  304  may also be described as attaching both the display  303  and the cover  302  to the housing  310 . The frame  304  may be formed of a polymer material, a metal material, or a combination of polymer and metal materials. The frame  304  may support elements of the display stack, provide anchor points for flexible circuits, and/or be used to mount other components and device elements. In some cases, the frame  304  includes one or more metal or conductive elements that provide shielding between device components, such as between the display stack (including display components and touch sensor components) and other components like the haptic actuator  322 , the speaker system  324 , and the like. 
     The cover  302 , display or display stack  303 , and frame member  304  may be part of a top module  301  of the device  300 . The top module  301  may be assembled as a subassembly, which may then be attached to a housing member. For example, as described herein, the display  303  may be attached to the cover  302  (e.g., via a transparent adhesive), and the frame member  304  may be attached (e.g., via adhesive) to the cover around a periphery of the display stack  303 . The top module  301  may then be attached to a housing member of the device  300  by mounting and adhering the frame member  304  to a ledge defined by the housing member. 
     The device  300  also includes a speaker module  350  that is configured to output sound via a speaker port. The speaker port may be positioned in and/or at least partially defined by a recess  351  of the cover  302 . As described herein, a trim piece may be positioned at least partially in the recess  351  to facilitate the output of sound while also inhibiting the ingress of debris, liquid, or other materials or contaminants into the device  300 . Output from the speaker module  350  may pass through an acoustic path defined at least in part by the speaker module  350  itself and the trim piece. In some cases, part of the acoustic path (e.g., between the speaker module  350  and the trim piece) is defined by the housing  310  and/or a molded material that is coupled to the housing  310 . For example, a molded material (e.g., a fiber-reinforced polymer) may be molded against a metal portion of the housing  310  (e.g., the housing member  313 , described herein). The molded material may also form one or more joint structures that also structurally join housing members together (e.g., the joint structures  318 ). A port may be defined through the molded material to acoustically couple the speaker module  350  to the trim piece and/or the recess  351  more generally, thereby directing sound from the speaker module  350  to the exterior of the device  300 . In some cases, a portion of the port that extends through the molded material is defined by a housing member itself, as described herein with reference to  FIGS.  6 A- 6 B . 
     As shown in  FIG.  3   , the device  300  also includes one or more cameras, light emitters, and/or sensing elements that are configured to transmit signals, receive signals, or otherwise operate along the front surface of the device. In this example, the device  300  includes a front camera  306  that includes a high-resolution camera sensor. The front camera  306  may have a 12 megapixel resolution sensor with optical elements that provide a fixed focus and an 85° field of view. The front camera  306  may have an aperture number of f/2.2. The device  300  also includes a facial recognition sensor  352  that includes an infrared light projector and infrared light sensor that are configured to sense an array of depth points or regions along the face of the user. The array of depth points may be characterized as a unique signature or bio-identifier, which may be used to identify the user and unlock the device  300  or authorize functionality on the device  300  like the purchase of software apps or the use of payment functionality provided by the device  300 . 
     The device  300  may also include one or more other sensors or components. For example, the device  300  may include a front light illuminator element for providing a flash or illumination for the front camera  306 . The device  300  may also include an ambient light sensor (ALS) that is used to detect ambient light conditions for setting exposure aspects of the front camera  306  and/or for controlling the operation of the display. 
       FIG.  3    also illustrates one or more cameras, light emitters, and/or sensing elements that are configured to transmit signals, receive signals, or otherwise operate along the rear surface of the device. As depicted in  FIG.  3   , these elements may be integrated in a sensor array  360 . In this example, the sensor array  360  includes a first camera  361  having a 12 megapixel image sensor and a wide angle lens with an aperture number of f/1.6. The first camera  361  may also include a sensor-shifting mechanism that allows for image stabilization and/or optical focusing. In some cases, the image sensor is moved with respect to one or more fixed elements of the optical lens assembly. The sensor array  360  also includes a second camera  362  having a 12 megapixel image sensor and a super-wide angle lens (120° FOV) with an aperture number of f/2.2. The sensor array  360  may also include a third camera  363  having a 12 megapixel image sensor and a telephoto optical lens assembly that enables 2.5× optical zoom. The third camera  363  may also have an aperture number of f/2.4. 
     The sensor array  360  also includes a light illuminator that may be used as a flash for photography or as an auxiliary light source (e.g., a flashlight). The sensor array  360  also features an integrated chassis design that minimizes space while providing the precision alignment required for multiple high-resolution cameras. In some cases, the sensor array  360  also includes a microphone, an ambient light sensor, and other sensors that are adapted to sense along the rear surface of the device  300 . 
     The sensor array  360  may also include a depth sensor  365  that is able to estimate a distance to objects positioned behind the device  300 . The depth sensor  365  may include an optical sensor that uses time-of-flight or other optical effect to measure a distance between the device  300  and an external object. The depth sensor  365  may include one or more optical emitters that are adapted to emit one or more beams of light, which may be used to estimate the distance. In some cases, the one or more beams of light are coherent light beams having a substantially uniform wavelength/frequency. A coherent light source may facilitate depth measurements using a time of flight, phase shift, or other optical effect. In some cases, the depth sensor  365  uses a sonic output, radio output, or other type of output that may be used to measure the distance between the device  300  and one or more external objects. The depth sensor  365  may be positioned proximate a window  371  (e.g., a region of the rear cover  372  or other component that covers the components of the sensor array  360 ) through which the depth sensor  365  may send and/or receive signals (e.g., laser light, infrared light, visible light, etc.). 
     As shown in  FIG.  3   , the cameras  361 ,  362 ,  363  may be aligned with camera covers  366 ,  367 ,  368 , respectively. The covers  366 ,  367 ,  368  may be formed from a glass or sapphire material and may provide a clear window through which the cameras  361 ,  362 ,  363  are able to capture a photographic image. In other cases, the covers  366 ,  367 ,  368  are optical lenses that filter, magnify, or otherwise condition light received by the respective camera  361 ,  362 ,  363 . The other sensing or transmitting elements of the sensor array  360  may transmit and/or receive signals through a region of the rear cover  372  or through a separate cover (e.g.,  369 ) that is coupled to the rear cover  372 . As shown in  FIG.  3   , the covers  366 ,  367 ,  368  may extend beyond the exterior surface of the cover  372 , and may define a recess along the interior side of the cover  372 , such that the lens or other element of the cameras  361 ,  362 ,  363  can extend into the respective recesses. In this way, the device  300  may accommodate a larger lens or other elements of the cameras  361 ,  362 ,  363  than would be possible if the recess were not provided. 
     The device  300  also includes a battery  330 . The battery  330  provides electrical power to the device  300  and its various systems and components. The battery  330  may include a 4.40 V lithium ion battery that is encased in a foil or other enclosing element. The battery  330  may include a rolled electrode configuration, sometimes referred to as “jelly roll” or folded electrode configuration. The battery  330  may be recharged via the charging port  332  (e.g., from a power cable plugged into the charging port  332  through a charging access opening  326 ), and/or via a wireless charging system  340 . The battery  330  may be coupled to the charging port  332  and/or the wireless charging system  340  via battery control circuitry that controls the power provided to the battery and the power provided by the battery to the device  300 . The battery  330  may include one or more lithium ion battery cells or any other suitable type of rechargeable battery element. 
     The wireless charging system  340  may include a coil that inductively couples to an output or transmitting coil of a wireless charger. The coil may provide current to the device  300  to charge the battery  330  and/or power the device. In this example, the wireless charging system  340  includes a coil assembly  342  that includes multiple wraps of a conductive wire or other conduit that is configured to produce a (charging) current in response to being placed in an inductive charging electromagnetic field produced by a separate wireless charging device or accessory. The coil assembly  342  also includes an array of magnetic elements that are arranged in a circular or radial pattern. The magnetic elements may help to locate the device  300  with respect to a separate wireless charging device or other accessory. In some implementations, the array of magnets also help to radially locate, orient, or “clock” the device  300  with respect to the separate wireless charging device or other accessory. For example, the array of magnets may include multiple magnetic elements having alternating magnetic polarity that are arranged in a radial pattern. The magnetic elements may be arranged to provide a magnetic coupling to the separate charging device in a particular orientation or set of discrete orientations to help locate the device  300  with respect to the separate charging device or other accessory. This functionality may be described as self-aligning or self-locating wireless charging. As shown in  FIG.  3   , the device  300  also includes a magnetic fiducial  344  for helping to locate the separate wireless charging device or accessory. In one example, the magnetic fiducial  344  is adapted to magnetically couple to a cable or power cord of the separate wireless charging device or other accessory. By coupling to the cable or power cord, the rotational alignment of the device  300  and the separate wireless charging device or other accessory may be maintained with respect to an absolute or single position. Also, by magnetically coupling the cable or cord to the rear surface of the device  300 , the charging device or other accessory may be more securely coupled to the device  300 . 
     In some implementations, the wireless charging system  340  includes an antenna or other element that detects the presence of a charging device or other accessory. In some cases, the charging system includes a near-field communications (NFC) antenna that is adapted to receive and/or send wireless communications between the device  300  and the wireless charger or other accessory. In some cases, the device  300  is adapted to perform wireless communications to detect or sense the presence of the wireless charger or other accessory without using a dedicated NFC antenna. The communications may also include information regarding the status of the device, the amount of charge held by the battery  330 , and/or control signals to increase charging, decrease charging, start charging and/or stop charging for a wireless charging operation. 
     The device  300  may also include a speaker system  324 . The speaker system  324  may be positioned in the device  300  so that a respective port  325  is aligned with or otherwise proximate an audio output of the speaker system  324 . Accordingly, sound that is output by the speaker system  324  exits the housing  310  via the respective port  325 . The speaker system  324  may include a speaker positioned in a housing that defines a speaker volume (e.g., an empty space in front of or behind a speaker diaphragm). The speaker volume may be used to tune the audio output from the speaker and optionally mitigate destructive interference of the sound produced by the speaker. The speaker system  324  may include left and right speakers that are aligned with left and right ports  325 , respectively, in order to produce stereo sound. 
     The device  300  may also include a haptic actuator  322 . The haptic actuator  322  may include a movable mass and an actuation system that is configured to move the mass to produce a haptic output. The actuation system may include one or more coils and one or more magnets (e.g., permanent and/or electromagnets) that interact to produce motion. The magnets may be or may include recycled magnetic material. As described herein, the haptic actuator  322  may have a profile or enclosure shape that facilitates physical integration with the battery  330  and other components of the device  300  in order to minimize space and/or maximize the size of the battery. 
     When the coil(s) are energized, the coil(s) may cause the mass to move, which results in a force being imparted on the device  300 . The motion of the mass may be configured to cause a vibration, pulse, tap, or other tactile output detectable via an exterior surface of the device  300 . The haptic actuator  322  may be configured to move the mass linearly, though other movements (e.g., rotational) are also contemplated. Other types of haptic actuators may be used instead of or in addition to the haptic actuator  322 . 
     The device  300  also includes a logic board  320  (also referred to herein as a circuit board assembly). The logic board  320  may include a substrate, and processors, memory, and other circuit elements coupled to the substrate. The logic board  320  may include multiple circuit substrates that are stacked and coupled together in order to maximize the area available for electronic components and circuitry in a compact form factor. The logic board  320  may include provisions for a subscriber identity module (SIM). The logic board  320  may include electrical contacts and/or a SIM tray assembly for receiving a physical SIM card and/or the logic board  320  may include provisions for an electronic SIM. The logic board  320  may be wholly or partially encapsulated to reduce the chance of damage due to ingress of water or other fluid. 
     The logic board  320  may also include wireless communications circuitry, which may be coupled to and/or otherwise use the housing members  311 ,  312 ,  313 ,  314 ,  315 , or  316  (or portions thereof) as radiating members or structures to provide wireless communications. The logic board  320  may also include components such as accelerometers, gyroscopes, near-field communications circuitry and/or antennas, compasses, and the like. In some implementations, the logic board  320  may include a magnetometer that is adapted to detect and/or locate an accessory. For example, the magnetometer may be adapted to detect a magnetic (or non-magnetic) signal produced by an accessory of the device  300  or other device. The output of the magnetometer may include a direction output that may be used to display a directional indicia or other navigational guidance on the display  303  in order to guide the user toward a location of the accessory or other device. 
     The device  300  may also include one or more pressure transducers that may be operable to detect changes in external pressure in order to determine changes in altitude or height. The pressure sensors may be externally ported and/or positioned within a water-sealed internal volume of the housing  310 . The output of the pressure sensors may be used to track flights of stairs climbed, a location (e.g., a floor) of a multi-story structure, movement performed during an activity in order to estimate physical effort or calories burned, or other relative movement of the device  300 . 
     The logic board  320  may also include global position system (GPS) electronics that may be used to determine the location of the device  300  with respect to one or more satellites (e.g., a Global Navigation Satellite System (GNSS)) in order to estimate an absolution location of the device  300 . In some implementations, the GPS electronics are operable to utilize dual frequency bands. For example, the GPS electronics may use L1 (L1C), L2 (L2C), L5, L1+L5, and other GPS signal bands in order to estimate the location of the device  300 . 
     The housing  310  may also include a chassis  319 , which may be attached to the housing  310 . The chassis  319  may be formed of metal, and may act as a structural mounting point for components of the device  300 . The chassis  319  may define an opening that corresponds to size of the coil assembly  342  of the wireless charging system  340 , such that the chassis  319  does not shield the wireless coil assembly  342  or otherwise negatively affect the inductive coupling between the coil of the wireless charging system  340  and an external wireless charger or accessory. 
     As shown in  FIG.  3   , the housing may include a cover  372  (e.g., rear or back cover) that may define a substantial entirety of the rear surface of the device  300 . The cover  372  may be formed from a glass, glass-ceramic, or other material having portions that are less than 1 mm thick. In some cases, the substrate has portions that are less than 0.80 mm. In some cases, the substrate has portions that are approximately 0.60 mm or less. The cover  372  may have a uniform thickness or, in some cases, may have a thickened or raised portion that surrounds the camera covers  366 ,  367 ,  368 . The cover  372  may be machined (e.g., ground) into a final shape before being polished and/or textured to provide the desired surface finish. The texture may be specially configured to provide a matte appearance while also being resistant to collecting a buildup of skin, lint, or other debris. A series of cosmetic layers may be formed along the inner surface of the cover  372  to provide a desired optical effect and final color of the device  300 . 
     Similar to as described above with respect to cover  302 , the cover  372  may be positioned at least partially within an opening defined in the housing  310 . Also similar to as described above with respect to cover  302 , the edges or sides of the cover  372  may be surrounded by a protective flange or lip of the housing  310  without an interstitial component between the edges of the cover  372  and the respective flanges of the housing  310 . The cover  372  may be chemically strengthened using an ion exchange process to form a compressive stress layer along exterior surfaces of the cover  372 . In some cases, the (rear) cover  372  is formed from the same or a similar material as (front) cover  302 . 
     As described above, the housing  310  may include housing members  311 ,  312 ,  313 ,  314 ,  315 , and  316  structurally joined together via joint structures  318 . The joint structures  318  (e.g., the material of the joint structures) may extend over inner surfaces of the housing members. More particularly, a portion of the joint structures  318  may contact, cover, encapsulate, and/or engage with retention features of the housing members that extend from the inner surfaces of the housing members. 
     Housing members  311 ,  312 ,  313 ,  314 ,  315 , and  316  may also be referred to herein as housing segments and may be formed from aluminum, stainless steel, or other metal or metal alloy material. As described herein, the housing members  311 ,  312 ,  313 ,  314 ,  315 , and  316  may provide a robust and impact resistant sidewall for the device  300 . In the present example, the housing members  311 ,  312 ,  313 ,  314 ,  315 , and  316  define a flat sidewall that extends around the perimeter of the device  300 . The flat sidewall may include rounded or chamfered edges that define the upper and lower edges of the sidewall of the housing  310 . The housing members  311 ,  312 ,  313 ,  314 ,  315 , and  316  may each have a flange portion or lip that extends around and at least partially covers a respective side of the front and rear covers  302 ,  372 . There may be no interstitial material or elements between the flange portion or lip and the respective side surface of the front and rear covers  302 ,  372 . This may allow forces or impacts that are applied to the housing  310  to be transferred to the front and rear covers  302 ,  372  without affecting the display or other internal structural elements, which may improve the drop performance of the device  300 . 
     As shown in  FIG.  3   , the device  300  includes multiple antennas that may be adapted to conduct wireless communication using a 5G communication protocol. In particular, the device  300  may include a (side-fired) antenna array  382  that is configured to transmit and receive wireless communication signals through an antenna window  383  or waveguide formed along or otherwise integrated with the side wall of the housing  310 . The side-fired antenna array  382  may be coupled to the logic board  320  via a flexible circuit element or other conductive connection, as described herein. The device  300  may also include a rear antenna module  384  that may include one or more (rear-fired) antenna arrays that may be configured to transmit and receive wireless communication signals through the cover  372 . The antenna module  384  may be attached to a back or bottom surface of the logic board  320 . 
     The antenna module  384  may include multiple antenna arrays. For example, the antenna module  384  may include one or more millimeter-wave antenna arrays. In the case where the antenna module  384  includes multiple millimeter-wave antenna arrays (each of which may include one or more radiating elements), the multiple millimeter-wave antenna arrays may be configured to operate according to a diversity scheme (e.g., spatial diversity, pattern diversity, polarization diversity, or the like). The antenna module  384  may also include one or more ultra-wideband antennas. 
     Each of the antenna arrays (e.g., the antenna array  384  and the millimeter-wave arrays of the antenna module  382 ) may be adapted to conduct millimeter wave 5G communications and may be adapted to use or be used with beam-forming or other techniques to adapt signal reception depending on the use case. The device  300  may also include multiple antennas for conducting multiple-in multiple-out (MIMO) wireless communications schemes, including 4G, 4G LTE, and/or 5G MIMO communication protocols. As described herein, one or more of the housing members  311 ,  312 ,  313 ,  314 ,  315 , and  316  may be adapted to operate as antennas for a MIMO wireless communication scheme (or other wireless communication scheme). 
       FIGS.  4 A- 4 B  depict a partial view of an example electronic device  400 . The portion illustrated in  FIGS.  4 A- 4 B  may correspond to an area  4 - 4  in  FIG.  1 A , though the same or a similar area may be found on other example devices described herein. The electronic device  400  may correspond to or be an embodiment of the electronic devices  100 ,  200 , or  300 , or any other device described herein.  FIGS.  4 A- 4 B  illustrates an example configuration of a speaker port  401  as well as a front-facing sensor region. 
     The device  400  includes a cover  402 , which may correspond to or be an embodiment of other covers described herein, such as the covers  102 ,  202 ,  302 , and a housing member  404 , which may correspond to or be an embodiment of other housing members described herein, such as the housing members  127 ,  213 ,  313 , and which may define at least a portion of four side surfaces of the device. As shown in  FIG.  4 C , the cover  402  may define a front surface  432 , a rear surface  434 , and a peripheral side surface  436  extending from the front surface  432  to the rear surface  434 . The peripheral side surface  436  is at least partially surrounded by a wall  407  of the housing  404  ( FIG.  4 C ). 
     The cover  402  defines a notch  406  along an edge of the cover  402 . The notch  406  (also referred to as a recess or cutout) may be along a top edge of the cover  402  to define a space between the edge of the cover  402  and housing member  404  that defines a top side of the device  400 . The space between the edge of the cover  402  and the housing member  404  may be referred to as a speaker port opening. A first side of the speaker port opening may be defined by the wall  407  of the housing member, and a second side of the speaker port opening may be defined by the notch  406  of the front cover  402 . The notch  406  may define at least three sides of the speaker port opening, including third and fourth sides of the speaker port opening, as shown in  FIGS.  4 A- 4 C . 
     The notch  406  may at least partially define an acoustic path of the device. For example, sound from a speaker positioned within the device may pass through the space defined by the notch (e.g., between a peripheral side surface of the cover  402  and the wall of the housing  404 ). Because the speaker port  401  is proximate the top of the device, the speaker port  401  is ultimately provided at an area of the device  400  that may be held against a user&#39;s ear during telephone calls or other uses. 
     The device  400  may include a speaker port cover structure  405  (also referred to as an acoustic port cover). The speaker port cover structure  405  may be positioned at least partially in the recess  406 , and between the edge portion of the cover  402  (into which the recess  406  is defined) and the housing member  404 . The speaker port cover structure  405  may include a trim piece  408  and a mesh member  410 . The trim piece  408  may be adjacent an edge of the cover  402  and adjacent the housing member  404 . The front surface of the trim piece  408  may be flush with the front exterior surface  432  of the cover  402 . In some cases, there is no interstitial component or material between the trim piece  408  and the cover  402 , or between the trim piece  408  and the housing member  404 . As described herein, the speaker port cover structure  405  provides a cover over a portion of an acoustic path in the device  400  that directs sound from a speaker module to the speaker port  401 . In some cases, the speaker port cover structure  405  also covers an acoustic path that couples to a microphone within the device, as described in greater detail herein. 
     The mesh member  410  may be configured to allow sound to pass through, while inhibiting ingress of dust, liquids, or other contaminants into the device  400 . The mesh member  410  may be a metal mesh, a polymer mesh, or the like. The mesh member  410  may be a unitary structure with holes or gaps formed therethrough (e.g. a perforated or molded polymer sheet), or it may be formed of multiple separate members (e.g., a woven fabric or metal mesh). In some cases, between about 30% and about 40% of the area of the mesh member  410  may be open (e.g., the openings or perforations defined by the mesh may make up between about 30% and about 40% of the area of the mesh member  410 ). In this way, sound may pass through the mesh member  410  without undue attenuation or other acoustic impact. 
       FIGS.  4 A- 4 B  also illustrate an example arrangement of components in a front-facing sensor array  411 , which may be at least partially surrounded by an active region  415  of the display. The front-facing sensor array  411  includes a front-facing camera  412 , a proximity sensor  414 , a combination flood illuminator and dot projector  416  (e.g., for projecting flood illumination and a pattern of dots onto an object, such as a user&#39;s face), and an infrared light sensor  418  (e.g., for capturing images of objects illuminated by the flood illuminator and dot projector). Each of the components in the front-facing sensor array  411  may be positioned below the cover  402  and may emit and/or receive light through the cover  402 . In some cases, a region of the cover  402  over a particular component of the front-facing sensor array  411  has a masking that is visually opaque, but transparent to the particular wavelengths of light that are utilized by an underlying sensor. For example, in some implementations, the combination flood illuminator and dot projector  416  and the infrared light sensor  418  are covered with a visually opaque, infrared transparent coating or material. 
     The front-facing sensor array  411  may be located in a portion of the front side of the device that is not an active display area. For example, the line shown enclosing the front-facing camera  412 , proximity sensor  414 , combination flood illuminator and dot projector  416 , and infrared light sensor  418  may indicate a boundary between an active region  415  of the display, and an area that does not include the display or that is not configured to produce graphical outputs. The front-facing sensor array  411  may include a mask, ink, coating, or other material, which may be visually opaque. 
       FIG.  4 B  depicts another view of the device  400 , showing additional details of the front-facing sensor array  411  and the speaker port  401 . In some cases, the speaker port  401 , and more particularly the trim piece  408  and mesh member  410 , may be positioned outside of a glue line  426 . The glue line  426  may adhere the cover  402  (and/or the top module) of the device to an underlying structure (e.g., the housing member  404 ), and may define a seal that inhibits ingress of dust, liquids, or other contaminants or debris into the device. Because the speaker port  401  is outside of the glue line  426 , other seals and sealing techniques may be used to inhibit ingress of dust, liquids, or other contaminants or debris into the device via the speaker port  401 . 
     As noted above, the speaker port cover structure  405  may provide acoustic access for both a speaker module and a microphone. In some cases, a separator  424  may be positioned in the speaker port cover structure  405  (as shown in greater detail with respect to  FIG.  4 C ) to increase the acoustic separation and/or isolation between the acoustic path to the microphone and to the speaker. As shown in  FIG.  4 B , the region  422  of the speaker port cover structure  405  may correspond to an acoustic path for a microphone (e.g., an acoustic input path), and the region  420  of the speaker port cover structure  405  may correspond to an acoustic path for the speaker (e.g., an acoustic output path). The separator  424  may be a piece of metal, plastic, or any other suitable material. 
       FIG.  4 C  depicts a partial exploded view of the device  400 , illustrating additional detail of the integration of the speaker port cover structure  405  with the cover  402 , the housing member  404 , and other device components.  FIG.  4 C  illustrates the mesh member  410  separated from the trim piece  408 . The mesh member  410  may be coupled to the trim piece  408  via adhesives, welds, brackets, fasteners, interference fit, latching structures, or the like. A separator  424  may be secured in a cavity of the trim piece  408  as well (e.g., below the mesh member  410 ). The separator  424  may be secured to the trim piece  408  via welding, adhesives, fasteners, interference fit, latching structures, or the like. The separator  424  may provide a barrier between the acoustic path to a microphone and the acoustic path to a speaker. 
     After the trim piece  408  is assembled with the mesh member  410  and optionally the separator  424 , the trim piece  408  may be attached to the cover  402  via adhesive members  430 . The adhesive members  430  (e.g., liquid adhesive, adhesive foam, pressure-sensitive adhesive (“PSA”), heat-sensitive adhesive (“HSA”), etc.) may adhere to the top sides of the flanges  428  of the trim piece and to an underside of the cover  402 . After the trim piece  408  is adhered to the cover  402  via the adhesive member  430 , the cover  402 , along with other top module components such as a display, may be attached to a frame member  427  via an adhesive  426 . The trim piece  408 , and in particular the flanges  428 , may be captured between the underside of the cover  402  and the frame member  427 . Further, the adhesive  426  may contact and/or at least partially surround the bottom sides of the flanges  428 , as well as other surfaces of the trim piece  408 , thereby contributing to the strength and stability of the trim piece  408  in the device. 
       FIG.  5    depicts an example cover structure  510  for use in a speaker port, as described herein. The cover structure  510  defines flanges  514 , as well as a recessed region  512 . The recessed region  512  may include holes, which may be defined by a mesh member, such as the mesh member  410 , or defined through the material of the cover structure  510  itself (e.g., by laser-forming, drilling, or otherwise forming holes through a wall structure of the cover structure  510 ). The recessed region may be recessed relative to a frame region  513  that surrounds the recessed region. In some cases, the recessed region corresponds to a thinned region of the cover structure  510 . For example, the thickness between the top (exterior) surface of the recessed region and the bottom (interior) surface of the recessed region may be less than the thickness between the top (exterior) surface of the frame region  513  and the bottom (interior) surface of the frame region  513 . Where the recessed region is part of the cover structure  510  itself, the recessed region may have a minimum thickness between about 20 microns and about 40 microns (e.g., 25 microns, 30 microns, 35 microns, etc.). The recessed region  512  may have a width dimension (e.g., the dimension  515 ). The dimension  515  may be about 0.4 mm, about 0.5 mm, about 0.6 mm, about 0.7 mm, or any other suitable dimension. The recessed region may be surrounded by the frame region  513 , as noted above. The frame region  513  may be between about 0.3 mm and about 0.6 mm thick. The holes in the mesh and/or defined through the cover structure  510  may have a diameter (or other opening size) between about 90 microns and about 110 microns (e.g., about 90 microns, about 100 microns, about 105 microns, about 110 microns, etc.). The web that defines the holes (e.g., the material of the cover structure that is between the holes) may have a minimum thickness between about 20 microns and about 40 microns (e.g., 25 microns, 30 microns, 35 microns, etc.). 
       FIG.  5    illustrates one example pattern of holes. In other examples, a monolithic cover structure may have a different pattern of holes and/or holes of a different size or shape (e.g., square-shaped holes, pentagon-shaped holes, etc.). For example, a first corner (e.g., proximate a top side of a device) of the perforated region may have a first minimum (e.g., smallest) radius of curvature, while a second corner (e.g., towards a bottom side of the device) has a second minimum radius of curvature that is different from the first minimum radius of curvature. The same radii of curvature may be mirrored on the opposite side of the perforated region. In this way, the perforated region exhibits an asymmetry about a horizontal axis (e.g., left-to-right in  FIG.  4 B ). In some cases, the frame region of a cover structure also exhibits a similar asymmetry about a horizontal axis, as defined by the top corners of the frame region having a minimum radius of curvature that is smaller than the bottom corners of the frame region. A minimum (e.g., smallest) thickness of the frame region (e.g., distance between the perforated region and the outer periphery of the cover structure) may be between about 0.2 mm and about 0.3 mm. In some cases, a minimum thickness of the frame region (e.g., distance between the perforated region and the outer periphery of the cover structure) may be between about 0.05 mm and about 0.2 mm. 
     In some cases, a perforated region may have corners with a substantially equal radius of curvature. For example, a first corner (e.g., proximate a top side of a device) of the perforated region may have a first minimum radius of curvature, and a second corner (e.g., towards a bottom side of the device) has a second minimum radius of curvature that is the same as the first minimum radius of curvature. The same radii of curvature may be mirrored on the opposite side of the perforated region. In this way, the perforated region is symmetrical about a horizontal axis (e.g., left-to-right in  FIG.  4 B ). In some cases, the frame region exhibits an asymmetry about a horizontal axis, or it may be substantially symmetrical (e.g., having four corners with substantially the same radius of curvature). 
     The corners of the perforated regions as described above, as well as the frame regions, may have a constant radius of curvature (e.g., they may define a portion of a circle), or a variable radius of curvature (e.g., they may define a non-circular spline). 
       FIG.  6 A  depicts a partial cross-sectional view of the device  400 , illustrating an acoustic path through the device and to (and through) the speaker port  401 . The device  400  includes a speaker module  620 , which may correspond to or be an embodiment of the speaker module  250 ,  350 , or any other speaker module described herein. The device  400  also includes a cover  402 , a display  610 , a frame member  611  coupled to an interior surface of the front cover  402 , and a back cover  604 . The speaker module  620  may be positioned below an active region of the display  610  (e.g., a region of the display  610  that is configured to display graphical output to a user). 
     The back cover  604  is attached to a housing structure via an adhesive  608 . The housing structure may be formed from or include the housing member  404  and a molded member  607 . The molded member  607  may be a polymer material (e.g., a fiber-reinforced polymer) that is molded against the housing member  404  and/or other housing members and/or components of the device  400 . In some cases, the molded member  607  is unitary with one or more joint structures and/or joining elements of the device  400  (e.g., joint structures  122 ,  218 ,  318 , joining elements  1416 ,  1418 ,  1420 ,  1422 ,  1424 , and  1426 , or any other joint structure/joining element described herein). Thus, the molded member  607  may define at least a portion of an exterior surface of the housing structure, as well as defining part of an acoustic path, as described herein. 
     The speaker module  620  may be coupled to the molded member  607 . For example, a portion of the speaker module  620  may be inserted into a hole defined by the molded member  607 .  FIG.  6 A  shows a portion of the speaker module  620  positioned in the hole of the molded member  607 , with a sealing member  632  (attached to the speaker module  620 ) forming a seal between the speaker module  620  and a surface of the hole. The sealing member  632  may form a seal between the acoustic path (defined by path portions  628 ,  630 , and  634 , for example) and other areas inside the device  400 . In particular, in some cases, water, liquids, or contaminants are not prevented from entering into the acoustic path through the speaker port  401 . Accordingly, the seal between the speaker module  620  and the molded member  607  may help prevent any water, liquids, or other contaminants that have entered the acoustic path from escaping into other areas of the device  400 , and may also help prevent acoustic losses as sound passes through the acoustic path. A barrier  622  (e.g., a mesh or other material that allows sound to pass through) may be positioned in the speaker module  620  and between a speaker driver  624  and the speaker port  401 . The barrier  622  may help inhibit liquids or contaminants from contacting or colleting on the speaker driver  624 . The speaker driver  624  may be or may include a speaker diaphragm, and may produce sound that is directed through the acoustic path to the speaker port  401 . More particularly, sound from the speaker driver  624  may pass through a first path portion  628 , a second path portion  630 , and a third path portion  634 , and ultimately through the speaker port  401  (e.g., through the mesh member  410  or other holes or openings provided in the speaker port  401 ). 
     As noted above, the acoustic path may be defined by path portions  628 ,  630 , and  634 . The first path portion  628  may be defined by the speaker module  620 , may extend from the speaker driver  624  to the second path portion, and may be configured to direct sound from the speaker driver  624  to the speaker port opening. At least a portion of the first path portion  628  may extend under an active region of the display  610 . At least a portion of the first path portion  628  may extend under the front-facing sensor array  411  ( FIGS.  4 A- 4 B ). The second path portion  630  may be defined by the molded member  607 . In some cases, the second path portion  630  is formed as a result of the molding process of the molded member  607 , while in some cases it is formed subsequently to the molding process (e.g., it is drilled or otherwise machined after the molded member  607  is molded against the housing member  404  and cured). A third path portion  634  may be defined by the housing member  404 . More particularly, at least one side or surface of the third path portion  634  may be defined by the housing member  404 . In some cases, another side or surface of the third path portion  634  (e.g., an opposite side or surface of the third path portion  634 ) may be defined by another component or structure of the device  400 , such as the frame member  611  of a top module (e.g., a frame member that is attached to the cover  402  and is used to couple the cover  402  to the molded member  607  and/or other device components or structures). 
       FIG.  6 B  depicts a partial cross-sectional view of the device  400 , showing the speaker module  620  decoupled from the molded member  607 , and illustrating a manner in which the speaker module  620  may be coupled to and sealed against the molded member  607 . 
     The speaker module  620  may be coupled to the molded member  607  via a translation indicate by arrows  648 . The translation may be substantially horizontal (as depicted in the figure), which may correspond to a lateral translation of the speaker module  620  in a positive y direction (e.g., towards the housing member  404 , which may correspond to the housing member  213  in  FIG.  2   , for example). 
     When the speaker module  620  is inserted into the hole defined in the molded member  607 , an end surface  646  of the speaker module may contact a surface  644  of the molded member  607 . The contact between the end surface  646  and the surface  644  may serve as a datum to define the y-position of the speaker module  620  in the device. Even if the end surface  646  does not contact the surface  644 , the end surface  646  and the surface  644  may together define a maximum y-position of the speaker module  620  in the device, and may help inhibit free movement of the speaker module  620 . 
     Similarly, the molded member  607  may define a hole having a sealing surface  640 , which the sealing member  632  contacts to seal the acoustic path. The sealing member  632 , which may be a polymer material such as a rubber, silicone (e.g., a molded liquid silicone rubber), foam, or the like, may be deformed against the sealing surface  640  to define the seal. The speaker module  620  may also define a flange portion  633  that acts as a hard-stop between the speaker module  620  and the molded member  607 . The flange portion  633  may define a maximum z-position of the speaker module  620  within the system and/or inhibit motion of the speaker module  620  in the z-direction. The vertical position or vertical direction in  FIG.  6 B  may be referred to as a z-position or z-direction (e.g., a direction extending generally perpendicularly from a rear cover to a front cover of a device). In some cases, the flange portion  633  may prevent the sealing member  632  from causing the speaker module  620  to be forced too far downward or upward (e.g., in the positive or negative z-direction) due to the forces produced by the deflection and/or deformation of the sealing member  632 . The flange portion  633  may extend above the interface between the sealing member  632  and the speaker module  620 , such that the flange portion  633  acts as a hard-stop in the z-direction before the sealing member  632  reaches maximum deformation or deflection. For example, a force that would tend to move or misalign the speaker module  620  in the z-direction would result in the flange portion  633  interfering with the molded member  607  or other structure, thereby inhibiting further movement of the speaker module  620  and defining the limits of its position in the z-direction (e.g., rather than allowing the force to continue to deform the sealing member  632  and produce more misalignment). 
       FIG.  6 C  depicts another example speaker module  650  and molded member  655  that may be used in a device as described herein. As shown in  FIG.  6 C , an end face of the speaker module  650  may be coupled to a corresponding face of the molded member  655  such that an outlet of the speaker module  650  communicates with a hole in the molded member  655  to direct sound through the acoustic path defined by the molded member  655 . A sealing member  652  may be positioned between the end face of the speaker module  650  and the corresponding face of the molded member  655  to provide an acoustic and/or environmental (e.g., liquid, debris) seal. The sealing member  652  may be a compliant material (e.g., a foam, an elastomer gasket). In some cases, the sealing member  652  is or includes an adhesive, such as an adhesive film, a PSA, HSA, or the like. The speaker module  650  may be secured to the device with fasteners, brackets, or the like and, in the case where the sealing member  652  is or includes adhesives, the speaker module  650  may be secured at least in part by the adhesive. 
     As noted above, the speaker port  401  may provide acoustic access to both an internal speaker and an internal microphone. In some cases, the device may include one or more structures configured to provide acoustic separation between the acoustic paths for the speaker and microphone. One example structure is the separator  424  that is positioned in the speaker port cover structure ( FIGS.  4 B,  4 C ).  FIG.  7 A  depicts a partial cross-sectional view of the device  400 , illustrating an acoustic path through the speaker port  401  to a microphone module  700 .  FIG.  7 A  illustrates an example boot member  714  (or simply boot  714 ) that may define part of an acoustic path from the speaker port  401  to the microphone module  700 . 
     In particular, a microphone module  700  may be coupled to an underside of a cover  402  and/or a top module. In some cases, as shown, the microphone module  700  is coupled to a substrate  702 , which is in turn coupled to a portion of a frame member  706  or other component of the top module (e.g., via an adhesive  704 ). The substrate  702  may define a hole  712  that allows the microphone module  700  to acoustically couple to the acoustic path defined through the frame member  706 . A membrane  713  may be positioned over the hole  712  (e.g., covering the hole) to inhibit the passage of water and/or other contaminants, while allowing the passage of sound. One or more additional membranes may be incorporated into the microphone module  700  as well. The membranes, including the membrane  713 , may be meshes, screens, foams, or the like, and may be formed of any suitable material, such as polymer, metal, or the like. 
     The frame member  706  may define a first path portion  710  of the acoustic path to direct sound from the speaker port  401  to the microphone module  700 . The frame member  706  may correspond to or be an embodiment of the frame member  204 ,  304 ,  611 , or any other frame member described. In other cases, the frame member  706  is a separate component that is coupled to the cover  402  and/or a separate frame or structural component of the device. 
     The boot  714  may be positioned at an end of the first path portion  710  and may define a second path portion  708  of the acoustic path. The boot  714  may be formed from a compliant material, such as an elastomer, and may seal against the frame member  706  (e.g., be in intimate contact with the frame member  706 ) to help define the acoustic path and inhibit acoustic interference between the acoustic path and other areas of the device. Stated another way, the boot  714  may seal against the frame member  706  to provide acoustic isolation to the acoustic path and the microphone module  700  more generally. 
     The boot  714  may define a corner or turn portion of the acoustic path to the microphone, and a portion of the boot  714  may extend at least partially into a cavity defined at least in part by the trim piece  408 . For example, in implementations that include a separator, such as the separator  424 , a cavity in the trim piece  408  may be defined on three sides by the trim piece  408 , and on a fourth side by the separator. A portion of the boot  714  (e.g., the top-most portion of the boot as shown in  FIG.  7 A ) may extend into the cavity so that sound entering through the mesh member  410  is directed along the acoustic path to the microphone, and so that sound from other sources (e.g., a speaker module) is inhibited from entering the acoustic path. Generally, the separator  424  may define two separated cavities or volumes along the underside of the speaker port cover structure, and the boot  714  may extend into one of those cavities or volumes, while the speaker module acoustically communicates to the other cavity or volume. This may provide a measure of acoustic isolation between the speaker and the microphone. 
       FIG.  7 B  depicts a partial cross-sectional view of the device  400 , illustrating an acoustic path through the speaker port  401  to another example microphone module  720 . As shown in  FIG.  7 B , and similar to  FIG.  7 A , the microphone module  720  may be coupled to an underside of a cover  402  and/or a top module. In some cases, as shown, the microphone module  720  is coupled to a substrate  722 , which is in turn coupled to a mounting plate  724 . The mounting plate  724  defines a base portion  725  and a waveguide  726  that extends from the base portion  725 . The waveguide  726  extends into a hole formed in the frame member  706  (or other component of the top module) and defines a portion of the acoustic path that is defined from the speaker port  401  to the microphone module  720 . More particularly, the acoustic path may be defined, at least in part, by the boot  714 , the channel defined through the frame member  706 , and the waveguide  726 . 
     A sealing member  727 , such as an O-ring, may define a seal between the waveguide  726  and the frame member  706  (or whatever other component(s) the waveguide  726  extends into). The interface between the waveguide  726  and the hole helps align the microphone module  720  with the frame member  706 . Further, the sealing member  727  helps form an acoustic and environmental seal between the acoustic path defined through the frame member  706  and to the microphone module  720 . For example, the sealing member  727  may inhibit water or other contaminants that may enter the acoustic path (e.g., through the speaker port  401 ) from escaping the acoustic path and entering other internal areas of a device. The sealing member  727  may also provide a retention force due to the friction between the sealing member  727  and the surfaces of the hole in the frame member  706  (optionally aided by the compression of the sealing member  727  between the frame member  706  and the waveguide  726 ). The sealing member  727  may be retained by a lip, channel, and/or groove defined by the waveguide  726 , as shown in  FIG.  7 B . 
     In some cases, the mounting plate  724  is adhered to the frame member  706 . Where an adhesive is used, it may be positioned between and adhered to the base portion  725  and the frame member  706 . Alternatively or additionally, the mounting plate  724  (and thus the microphone module  720  and substrate  722 ) may be secured to the frame member  706  using brackets, cowlings, fasteners, or the like. In some cases, the friction from the sealing member  727  is sufficient to retain the mounting plate  724  to the frame member  706 . 
     The substrate  722 , to which the microphone module  720  may be soldered, adhered, or otherwise secured, may be secured to the mounting plate  724  via an adhesive  728  (e.g., a PSA, HSA, adhesive foam, or the like). The substrate  722  may be a circuit board (e.g., a rigid or flexible circuit board), and may include conductive traces that interconnect the microphone module  720  with other circuitry of the device. 
     A membrane  729  may be positioned over a hole in the substrate  722  (e.g., covering the hole) to inhibit the passage of water and/or other contaminants into the microphone module  720 , while allowing the passage of sound. The membrane  729  may be a mesh, screen, foam, or the like, and may be formed of any suitable material, such as polymer, metal, or the like. The membrane  729  may be positioned in place using a compliant stack  730 , which may include one or more layers of adhesive, foam, and/or other materials. The compliant stack  730  may adhere or be adhered to both the base portion  725  of the mounting plate  724  and the substrate  722 . 
       FIG.  7 C  depicts an exploded view of the microphone subassembly shown in  FIG.  7 B , illustrating additional details of the components of the microphone subassembly. As shown in  FIG.  7 B , the sealing member  727  may be positioned around the waveguide  726 , which defines a lip (as shown), groove, slot, or other retention feature that retains the sealing member  727  in place on the waveguide  726 . The base portion  725  of the mounting plate  724  is secured to the substrate  722  (e.g., a circuit board and/or circuit board assembly) via an adhesive  728  (e.g., an HSA, PSA, adhesive foam, etc.). The adhesive  728  may define a hole in which the membrane  729  and compliant stack  730  may be positioned. As described above, the membrane  729  may be positioned over a hole  731  that extends through the substrate  722  and provides acoustic access to the microphone module  720 . In some cases, the surface(s) that define the hole  731  are considered part of the acoustic path that extends from the speaker port  401  to the microphone module  720 . 
     The microphone module  720  may include conductive pads  732  that are conductively coupled (e.g., soldered) to corresponding conductive pads on the substrate  722  to facilitate communicative coupling between the microphone module  720  and other circuitry. The microphone module  720  also includes a microphone sensor element  733 . As shown in  FIG.  7 C , the microphone sensor element  733  is positioned proximate the hole  731 , though in other cases it may be positioned elsewhere in the microphone module  720 . 
       FIG.  8 A  depicts another view of the boot  714  of  FIG.  7 A , showing how the boot  714  may be integrated with the cover  402  and the frame  706 . In particular, the boot  714  may be positioned below the trim piece  408  and against the frame member  706  in the area where the first path portion through the frame member  706  ends. As shown, an adhesive  800  (e.g., a PSA, HSA, adhesive foam, etc.) may adhere the boot  714  to the frame member  706 . 
       FIGS.  8 B- 8 C  depict other example configurations of boots and/or acoustic separators that may be used to acoustically isolate a speaker from a microphone.  FIG.  8 B  shows a cover  810  separated from a frame member  811 . The frame member  811  (which may be an embodiment of the frame member  706 ) defines an output port  809  at an end of an acoustic path portion defined by the frame member  811 . A microphone may be coupled to the frame member  811  along a bottom surface of the frame member (as shown in  FIG.  7 A ), optionally before the frame member  811  is attached to the cover  810 . A boot  814  may be attached to the frame member  811  with adhesive  816 . The boot  814  may define a snout-portion that extends into the recess defined under the trim piece  812 , in a manner similar to the boot  714  in  FIG.  7 A . The boot  814  may be attached to the frame member  811  prior to the frame member  811  being coupled to the cover  810 . 
       FIG.  8 C  depicts an acoustic isolation structure  824  that may be positioned below the trim piece  822 . The acoustic isolation structure  824  may include a first passage  826  for porting sound to a microphone module, and a second passage  828  for porting sound to a speaker module. The first and second passages  826 ,  828  may define portions of the acoustic paths to the microphone and speaker modules, respectively. The acoustic isolation structure may be adhered or otherwise attached to the cover  820  and/or the frame member  821 , and may be attached after the frame member  821  is coupled to the cover  820 . 
       FIG.  9 A  depicts a portion of a device  900 . The device  900  may correspond to or be an embodiment of the device  100 ,  140 ,  200 ,  300 , or any other device described herein. The device  900  is shown without a cover and/or display, such that internal components of the device  900  are visible.  FIG.  9 A  shows a housing  904 , as well as a frame member  906  of a top module (or a representation of where a frame member would be). 
       FIG.  9 A  generally illustrates a front-facing sensor region  901 . With the exception of an ambient light sensor  922 , the components of the front-facing sensor region  901  may be outside of an active area of the display. The front-facing sensor region  901  (which may also be referred to as a notch, due to the manner in which it extends downward into the display region) may have a width  903  that is less than about 60%, less than about 50%, or less than about 40% of the width of the display area  902 . In some cases, one or more of the components in the front-facing sensor region  901  provide multiple functions, thereby allowing the width of the front-facing sensor region  901  to be minimized or reduced. In some cases, the width  903  of the front-facing sensor region  901  is about 30 millimeters or less. 
     The device  900  includes, in the front-facing sensor region  901 , a front-facing camera  908 , a proximity sensor  912 , a combination flood illuminator and dot projector  918  (e.g., a biometric sensor module), and an infrared light sensor (or camera)  920 . The device  900  also includes an ambient light sensor  922  positioned within an active display region  902  of the device  900 .  FIG.  9 A  also illustrates an example positioning of a microphone module  910 , which may be attached to an underside of the frame member  906 . As described herein, the microphone module  910  may communicate with an acoustic boot  914  in the speaker port of the device  900 . 
     The combination flood illuminator and dot projector  918  (which may correspond to or be an embodiment of the combination flood illuminator and dot projector  416 ) may be or may include a biometric sensor module. The combination flood illuminator and dot projector  918  may project both an infrared flood illumination of an object, as well as a pattern of infrared dots or points of light. The infrared light sensor (or camera  920 ) may capture an image of an object (e.g., a user&#39;s face) using the projected flood illumination and dot pattern. The images captured by the sensor  920  may be used to authenticate a user, as described above. Further, by combining the flood illuminator and dot projector into a single module, valuable space may be saved in the front-facing sensor region  901 , thereby allowing for a greater amount of active display area to be provided. 
       FIG.  9 B  depicts a partial cross-sectional view of the device  900 , viewed along line  9 B- 9 B in  FIG.  9 A , depicting an example configuration of the front-facing camera  908 . The front-facing camera  908  may include a lens assembly  923  and an image sensor  924 , both contained in a housing  921 . The camera  908  may be an auto-focus camera in which the lens assembly  923  is configured to extend, contract, or otherwise change length or position within the housing  921  to focus an image on the image sensor  924 . In such cases, a front surface of the lens assembly  923  may be configured to move vertically as indicated by arrow  928 . 
     In cases where the front surface of the lens assembly  923  moves towards and/or away from the cover  929  (e.g., the front cover of the device  900 ), it may not be feasible to mount the lens assembly  923  directly to the interior surface of the cover  929 . Accordingly,  FIG.  9 B  illustrates an example configuration for mounting an auto-focus camera to the interior side of a cover  929 . For example, the housing  921  may be coupled to a mounting bracket  925  (e.g., via adhesive, welding, soldering, brazing, fasteners, or the like). The mounting bracket  925  may be attached to the interior surface of the cover  929 , such as via adhesive  927 , fasteners, or the like. The mounting bracket  925  may have a height that provides sufficient clearance between the lens assembly  923  and the interior surface of the cover  929  to facilitate the necessary movement of the front of the lens assembly  923  (indicated by arrow  928 ). 
     The mounting bracket  925  and the adhesive  927  may extend completely around the periphery of the lens assembly. In this way, the mounting bracket  925  and the adhesive  927  inhibit ingress of dust or other contaminants into the housing  921  and prevent light from the display  926  (or other light sources) from entering the lens assembly  923  and potentially negatively affecting images captured by the camera or otherwise interfering with the operation of the camera. 
     While  FIG.  9 B  illustrates an auto-focus camera, the same or similar construction may be used for fixed focus cameras as well. In such cases, the lens assembly may not be configured to move vertically, but instead may remain in a fixed length and/or position within the housing. 
       FIG.  9 A  depicts an example device  900  in which components of a front-facing sensor region are positioned outside of an active region of the display, in a “notch” region. In such cases, the display may define a notch-like recess or shape to accommodate the front-facing sensor region, such that the display stack is not positioned between the sensors and the cover (e.g., the sensors are not covered by the display). In other example devices, the display defines one or more additional holes, openings, or discontinuities, in addition to or instead of the “notch,” to accommodate one or more components of the front-facing sensor region. For example,  FIGS.  9 C and  9 D  illustrate an example electronic device  930  in which a front-facing camera  932  is positioned below a hole formed through a display stack  934 . The display stack  934  may also define a cut-away region, or notch, in which other components of the front-facing sensor region may be positioned (e.g., a microphone module, a flood and dot projector, an infrared light sensor, or the like). 
     In some cases, the region  933  of the display stack  934  that extends around (or partially around) the front-facing camera  932  is an active portion of the display. For example, the region  933  may produce graphical outputs. In other cases, the region  933  is an inactive region of the display stack  934  (e.g., that region of the display stack may be incapable of producing graphical outputs, or it may be capable of producing graphical outputs but configured to remain inactive). In cases where the region  933  is an inactive region of the display, a paint, ink, dye, mask, layer, or the like may be positioned on top of the display in that region such that the region  933  has a matching visual appearance to the other areas of the front-facing sensor region. 
     A border  931  may extend around the camera  932  to visually indicate that the camera  932  is within the front-facing sensor region, and to provide vertical symmetry to the front-facing sensor region. In such cases, the border shown above and to the right of the camera  932  in  FIG.  9 C  may not be present. The border  931  may be a paint, ink, dye, or other structure or material. 
       FIG.  9 D  depicts a partial cross-sectional view of the device  930  of  FIG.  9 C , illustrating an example configuration of the camera  932  and the display stack  934 . The camera  932 , which may be an autofocus or fixed focus camera, may include a lens assembly  937  and an image sensor  938 , both contained in a housing  939 . The camera  932  may also include a shroud  936  that is attached to the housing  939  and to the display stack  934  (e.g., with adhesive  940 ). The shroud  936  and the adhesive  940  may extend completely around the periphery of the lens assembly. In this way, the shroud  936  and the adhesive  940  inhibit ingress of dust or other contaminants into the housing  939 . Further, the shroud  936  extends almost completely to (and optionally contacts) the interior surface of the cover  935  (which may be an embodiment of the cover  102 , or any other front covers described herein), thereby shielding the lens assembly  937  from light emitted from the sides of the display  934 , which may otherwise enter the lens assembly  937  and potentially negatively affecting images captured by the camera or otherwise interfering with the operation of the camera. 
       FIG.  9 D  depicts the camera  932  positioned in a hole in the display stack  934 , such that the display stack surrounds the wall portion of the shroud  936  (as illustrated by the display stack  934  having portions both on the left and right side of the shroud  936 ). The same or similar shroud construction may also be used in implementations where the camera  932  is not positioned in a hole in a display stack  934 . In such implementations, the portion of the display stack  934  that is shown on the left side of  FIG.  9 D  may not be present and/or it may be replaced by a different structural component. 
       FIG.  9 E  depicts a partial cross-sectional view of another example configuration of a front-facing camera. The camera  942 , which may be an autofocus or fixed focus camera, may include a lens assembly  941  and an image sensor  951 , both contained in a housing  943 . The camera  942  may also include a shroud  944  that is attached to the housing  943  and optionally to the display stack  946  (e.g., with adhesive  945 ) and optionally to a frame or other component of the top module of a device. In some cases, the shroud  944  is not attached to the display stack  946 . The camera  942  also includes a ring member  947  that is attached to the shroud  944  (e.g., via adhesive  945 ) and to the interior surface of the cover  949  (which may be an embodiment of the cover  102 , or any other front covers described herein). The ring member  947  may extend completely around the periphery of the lens assembly, and may be adhered to the interior surface of the cover  949  via adhesive  948  (e.g., PSA, HSA, adhesive foam, or the like). In this way, the ring member  947  and the adhesive  948  inhibit ingress of dust or other contaminants into the housing  943 . Further, because the ring member  947  is adhered to or otherwise contacts the interior surface of the cover  949 , the ring member  947  shields the lens assembly  941  from light emitted from the side of the display  946 , which may otherwise enter the lens assembly  941  and potentially negatively affecting images captured by the camera or otherwise interfering with the operation of the camera. The configuration of the camera in  FIG.  9 E  may be implemented in a device with a hole through its display stack to accommodate the camera (as shown in  FIG.  9 C ), or in a device where the camera is positioned outside the outer periphery of the display (as shown in  FIG.  9 A ). In the former case, component  950  may represent part of the display stack  946 , while in the latter case, component  950  may represent a frame or other component of the top module of a device. 
       FIG.  9 F  depicts a partial cross-sectional view of another example configuration of a front-facing camera  952 . The camera  952 , which may be an autofocus or fixed focus camera, may include a lens assembly  953  and an image sensor  962 , both contained in a housing  954 . The camera  952  may also include a shroud  956  that is attached to the housing  954  and optionally to the display stack  958  (e.g., with adhesive  957 ) and optionally to a frame or other component of the top module of a device. In some cases, the shroud  956  is not attached to the display stack  958 . 
     As shown in  FIG.  9 F , the shroud  956  does not contact or otherwise extend sufficiently towards the cover  961  to shield the lens assembly  953  from light that may leak from the edge of the display stack  958 . Accordingly, a shield  959  may be applied to an edge of the display stack  958 . The shield  959  may be a paint, ink, dye, film, or other material or component that is opaque or otherwise blocks or reduces light from leaving the display stack  958  through the edge. In some cases, any edge of the display stack  958  that is proximate an optical device, such as a lens assembly, image sensor, light sensor, etc., may include a shield similar to the shield  959  along that edge. 
     The configuration of the camera in  FIG.  9 F  may be implemented in a device with a hole through its display stack to accommodate the camera (as shown in  FIG.  9 C ), or in a device where the camera is positioned outside the outer periphery of the display (as shown in  FIG.  9 A ). In the former case, component  960  may represent part of the display stack  958 , while in the latter case, component  960  may represent a frame or other component of the top module of a device. Where the component  960  represents part of the display stack  958 , the edge of that portion of the display stack that is exposed to the camera  952  may include a shield similar to the shield  959 . In such cases, the shield  959  may be a single unitary component, such as a film, paint, ink, dye, or the like, that extends along a continuous edge of the display stack. 
       FIGS.  9 B and  9 D- 9 F  illustrate example lens configurations that include mitigations to prevent or limit the effects of light contaminants (e.g., dust) on the operation of the camera. For example,  FIG.  9 B  describes a mounting bracket that attaches to an interior surface of a cover to seal the camera;  FIG.  9 D  describes a shroud that extends around the periphery of a lens assembly to block light;  FIG.  9 E  describes a ring member  947  that attaches to an interior surface of a cover to seal the camera; and  FIG.  9 F  describes a paint or other coating that is applied to the edge of a display stack to reduce or prevent light leakage. 
     Cameras may also or alternatively be at least partially encapsulated by a curable material to help prevent or limit light leakage and other contamination.  FIG.  9 G  illustrates a portion of a device with a front-facing camera, illustrating how a camera, such as any of the cameras shown or described in  FIGS.  9 A- 9 F , may be at least partially encapsulated. In particular, a front-facing camera  962  (which may be an embodiment of the cameras  908 ,  932 ,  942 ,  952 , or any other front-facing camera described herein) may be positioned in a front-facing sensor region of a device. The camera  962  may be positioned in a gap or space that is between a frame member  964  (which may be a polymer, metal, laminate stack, or other member or assembly of a top module) and a display stack  963 . The frame member  964  and/or the display stack  963  may define curves or contours to at least partially surround or frame the camera  962 . A gap  969  may be defined between the camera  962  and the frame member  964  and the display stack  963 . 
     The camera  962  may be attached to or otherwise positioned proximate the interior surface of a cover.  FIG.  9 G  shows a device with the cover removed for ease of illustration, but it will be understood that a cover may be positioned over the camera  962 , the display stack  963 , and the frame member  964  (e.g., as if the cover is placed directly on the page). 
     In order to at least partially encapsulate the camera  962 , a curable material may be introduced into the spaces between the display stack  963  and the frame member  964  (e.g., spaces  968  and  967 ) and into the gap  969 . The curable material may be introduced through one or more holes (e.g., holes  965 ,  966 ) formed through a back component of the top module, such as a plate (e.g., the metal plate  1314 ,  FIG.  13 A ). The curable material may flow along the interior surface of the cover, through the spaces  967  and  968 , and into the gap  969 . In some cases, one of the holes  965 ,  966  is used as an injection port, and the other is used as a vent (or vacuum) port to help draw the curable material into the desired locations. The curable material may at least partially surround the camera and may abut (and optionally adhere to) a housing, shroud, ring member, or other component of the camera, as well as contacting (and optionally adhering to) the interior surface of the cover and any other components that it comes into contact with. The curable material may then be allowed to cure to form a seal around the camera  962 . As noted above, the cured material may help seal the camera  962  against light and contaminants. The curable material may be an epoxy, glue, thermoset polymer, or the like. 
       FIG.  9 H  depicts a partial exploded view of a device, showing example techniques for aligning and/or securing a front-facing camera  972  to the top module.  FIG.  9 H  illustrates a cover  970  and a frame member  978  defining a camera hole  976 . The frame member  978  may be an assembly comprising multiple components or materials, and may be configured to be attached to the cover  970  and to provide structural rigidity to the top module and attach the top module to other components of a device. The frame member  978  may include other holes, openings, features, or the like, to accommodate or attach to other top module components (including, for example, components of a front-facing sensor array), though for simplicity only the camera hole  976  is shown in  FIG.  9 H . 
     The camera  972  may be attached to the frame member  978  via adhesives, fasteners, brackets, or any other suitable technique. A lens assembly, shroud, or other portion of the camera  972  may extend through the hole  976  in the frame member  978 , and may attach to or otherwise be proximate the interior surface of the cover  970 , as shown and described with respect to  FIGS.  9 B and  9 D- 9 F . The frame member  978  may include either or both of an alignment ring  974  or an alignment pin  975 . The alignment ring  974  may be affixed to the frame member  978  so that a hole through the alignment ring  974  is properly positioned relative to the hole  976 . The camera  972  may be attached to or otherwise secured against the alignment ring  974 . The alignment ring  974  may be configured to contact the camera  972  and position the camera  972  in a fixed position relative to the alignment ring  974 , thereby establishing and fixing the position of the camera  972  in the device. For example, a shroud or other cylindrical component of the camera  972  may contact the inner surface of the hole through the alignment ring  974  to establish and fix the relative positions of the camera  972  and the frame member  978  (at least within a plane parallel to the cover  970 ). Alternatively or additionally, the frame member  978  may include an alignment pin  975  protruding from the frame member  978 . The camera  972  may define an alignment pin receptacle  973  (e.g., a blind hole formed into the camera  972 ) into which the alignment pin  975  extends. When the camera  972  is assembled onto the frame member  978 , the interface between the alignment pin  975  and the alignment pin receptacle  973  establishes and fixes the relative position of the camera  972  and the frame member  978  (at least within a plane parallel to the cover  970 ). 
       FIG.  10 A  depicts a partial cross-sectional view of the device  900  viewed along line  10 A- 10 A in  FIG.  9 A .  FIG.  10 A  illustrates an example arrangement of the combination flood illuminator and dot projector  918  and the infrared light sensor  920 , shown below a cover  1000  (e.g., corresponding to the cover  102  or any other cover described herein). 
     The infrared light sensor  920  may include a lens assembly  1012  (also referred to as a second lens) and a light receiver, such as a sensor element  1018 . The lens assembly  1012  may include one or more lens elements and may focus an image onto the light receiver (e.g., the sensor element  1018 ) to capture an object that is illuminated by the flood and/or dot pattern projected by the combination flood illuminator and dot projector  918 . In some cases, the infrared light sensor  920  produces a depth map of a user&#39;s face (or other object) based on the way in which the user&#39;s face reflects the dot pattern. The sensor element  1018  may be coupled to a substrate  1016  and the lens assembly  1012 , the sensor element  1018 , and the substrate  1016  may be contained in a housing  1014 . The housing  1014  may also contain components of the combination flood illuminator and dot projector  918 . 
     The combination flood illuminator and dot projector  918  includes a lens assembly  1002  (also referred to as a first lens), a dot pattern light source  1004  (also referred to as a first light source and/or light emitter), and a flood illumination light source  1006  (also referred to as a second light source and/or light emitter). The lens assembly  1002  may include one or more lens elements. The dot pattern light source  1004  may produce and/or emit a pattern of light (e.g., a pattern of dots or points of infrared light), which may be projected, through the lens assembly  1002 , onto an object. The dot pattern may be a grid of discrete points of light, or a set of discrete points of light in another arrangement. 
     The dot pattern light source  1004  may be positioned relative to the optical axis  1007  of the lens assembly  1002  such that the dots are substantially in focus and/or the dot pattern maintains a pattern of discrete dots or points of infrared light. In some cases, the dot pattern light source  1004  is aligned with an optical axis  1007  of the lens assembly  1002  or otherwise positioned below a central region of the lens assembly  1002 , as shown in  FIG.  10 A . In some cases, the dot pattern light source  1004  includes multiple discrete light-producing elements. In other cases, a pattern or mask is provided over one or more light-producing elements to produce the pattern of dots. 
     The flood illumination light source  1006  may be configured to produce a more uniform flood of light (as compared to the dot pattern of the dot pattern light source  1004 ). In order to produce the flood of light, the flood illumination light source  1006  may be offset from the optical axis  1007  of the lens assembly  1002 , such that it is positioned below a peripheral region of the lens assembly  1002  (e.g., a region about a periphery of the lens assembly  1002  and around the central region of the lens assembly  1002 ). For example, as shown in  FIG.  10 A , the flood illumination light source  1006  may be offset from the optical axis  1007  by a distance  1010 . In some cases, the flood illumination light source  1006  may also be positioned at a different height, relative to the lens assembly  1002 , than the dot pattern light source  1004 . For example, as shown in  FIGS.  10 A- 10 C , the flood illumination light source  1006  may be closer to the lens assembly  1002  (e.g., it may be mounted on a spacer  1005  or otherwise positioned nearer to the lens assembly  1002 ). In other cases it may be positioned lower than the dot pattern light source  1004  (e.g., further from the lens assembly  1002 ). The positioning of the dot pattern light source  1004  and the flood illumination light source  1006  may be related to a focal plane of the lens assembly  1002 . For example, in some cases, the dot pattern light source  1004  is positioned at or in the focal plane of the lens assembly  1002 , and the flood illumination light source  1006  is offset from (e.g., not in) the focal plane of the lens assembly  1002 . In other cases, the dot pattern light source  1004  and the flood illumination light source  1006  are offset by different distances from the focal plane of the lens assembly  1002 . 
     By positioning the flood illumination light source  1006  away from the optical axis  1007  (and optionally closer to or further from the lens assembly  1002  than the dot pattern light source  1004 ), the light emitted by the flood illumination light source  1006  may be blurred or otherwise projected in a diffuse pattern, even if the light emitted by the flood illumination light source  1006  is one or multiple point sources of light. More particularly, light passing through the lens assembly  1002  at a distance from the optical axis (e.g., near an outer periphery of the lens elements in the lens assembly  1002 ) may not be rendered in focus, and instead may be blurry and/or diffuse, thereby producing a flood-like illumination pattern. In some cases, the illumination pattern produced by the flood illumination light source  1006 , as projected by the lens assembly  1002 , may substantially uniformly illuminate a user&#39;s face with a flood of infrared light when the device is held within a particular distance from the user&#39;s face (e.g., between about 6 inches and about 4 feet, or any other suitable distance range). In this way, the infrared light sensor  920  can capture an image (e.g., an infrared image) of the user&#39;s face for purposes of authentication or the like. More particularly, the flood of infrared light is reflected by the user&#39;s face to produce an image of the user&#39;s face via the light sensor  920  (and more particularly the sensor element  1018 ). 
       FIG.  10 B  illustrates the dot pattern illumination light source  1004  projecting a pattern of dots through the lens assembly  1002 , as illustrated by the illumination pattern  1020 . For example, the central region of the lens assembly  1002  may focus the pattern of light emitted by the dot pattern illumination light source  1004  onto an object. 
       FIG.  10 C  illustrates the flood illumination light source  1006  projecting a diffuse, flood-like pattern of illumination along an off-axis path through the lens assembly  1002 , as illustrated by the illumination pattern  1022 . While  FIGS.  10 B and  10 C  each illustrate only one illumination pattern, it will be understood that both illumination patterns may be produced at the same time. In some cases, the illumination patterns are produced in an alternating pattern, such that each illumination pattern is incident on an object for a period of time in which the other is not incident on the object. 
     In some cases, the flood illumination light source  1006  includes multiple light emitting elements, such as an array of light emitting elements positioned in a radial array, with each light emitting element offset from the optical axis  1007 . Both the flood illumination light source  1006  and the dot pattern illumination light source  1004  may be or may include one or more infrared laser light sources, such as vertical-cavity surface-emitting laser (“VCSEL”) modules, or any other suitable light-producing elements. As described above, the VCSEL modules may produce light in an infrared spectrum. In some cases, the light produced by the flood illumination light source  1006  and the dot pattern illumination light source  1004  is not generally visible to the unaided human eye. 
       FIG.  11 A  depicts a partial cross-sectional view of the device  900 , viewed along line  11 A- 11 A in  FIG.  9 A , and illustrating an example configuration of the ambient light sensor  922 . The ambient light sensor  922  may include a light sensor module with a light sensing element  1110  and a light-transmissive cover element  1112  (e.g., a glass, polymer, sapphire, or other light-transmissive material(s)) in a housing  1114 . The light-transmissive cover element  1112  (e.g., diffuser) may be configured to diffuse light to produce a more uniform illumination on the light sensing element  1110 . The light sensing element  1110  may be a photo-sensitive system or component, and may detect various characteristics of light, including intensity, color, color temperature, or the like. 
     The housing  1114  may be attached to a bracket  1108 , which may in turn be attached to a layer  1104  below display components  1102  (e.g., display layers). The bracket  1108  may be attached to the layer  1104  via adhesive, for example. The layer  1104  may be part of a display stack that includes both the layer  1104  and the display components  1102 , or it may be a separate component. The display components  1102  may include one or more display layers that produce graphical outputs visible through a cover  1100 , as well as one or more electrode layers that provide touch and/or force-sensing functionality. As described in greater detail with respect to  FIGS.  11 B- 11 C and  12 A- 12 B , the ambient light sensor  922  may be configured to detect an ambient light (e.g., light outside of the device) through the display  1102  and the cover  1100 . 
     The layer  1104  may be an opaque masking layer that defines a hole  1105 . The hole  1105  may define the smallest aperture in the optical system that includes the ambient light sensor  922 , and thus may be the limiting factor in the amount and angle of light that can enter the ambient light sensor  922 . The area of the hole  1105  may be smaller than the area of the light sensing element  1110 . 
     The layer  1104  may be formed from any suitable material, such as a metal (e.g., a metal plate or metal foil), polymer, ink, or the like. In some cases, the location of the hole  1105  is tightly controlled with respect to the display components  1102 , such that the hole  1105  is aligned with a known set of pixels defined by the display components  1102 . Thus, as described below, the device can compensate for the light being produced by the pixels above and/or nearby the hole  1105  with specificity. By forming the hole in a layer  1104  that is part of the display stack, a high degree of accuracy can be achieved between the location of the hole  1105  and the intended pixels. By contrast, if the light-limiting aperture of the system were positioned in the ambient light sensor  922 , the accuracy of the alignment between the ambient light sensor  922  and the hole  1105  would be dependent on the accuracy of the assembly of the ambient light sensor  922  to the display stack, which may be lower than can be achieved by forming the hole in a layer of the display stack itself. Further, because the layer  1104  is part of the display stack, it may be securely retained to the other layers of the display stack, such as via adhesive (e.g., an adhesive that extends along the entire or substantially the entire area of the display stack between the layer  1104  and an adjacent layer of the display stack). This coupling between the layer  1104  and the adjacent layer of the display stack provides a stable, durable alignment between the hole  1105  and the pixels above and/or nearby the hole  1105 . Further, by forming the smallest aperture (e.g., the hole  1105 ) in a layer of the display stack, rather than a separate component that may be knocked loose or otherwise more likely to shift relative to the display stack, the alignment between the hole  1105  may remain stable through extensive use. 
     In some cases, the ambient light sensor  922  is positioned proximate an edge or boundary of the active area of the display stack in order to reduce the amount of light from the display that can enter the ambient light sensor. For example, the ambient light sensor  922  (and more particularly the hole  1105 ) may be positioned about 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm, or any other suitable distance (e.g., left-to-right in  FIG.  11 A ) from the edge of the active area of the display. The hole  1105  may have dimensions of between about 0.25 and about 0.75 mm in the y-direction of the device (left-to-right in  FIG.  11 A ), and between about 5.0 and about 7.0 mm in the x-direction of the device (into the page in  FIG.  11 A ). 
       FIGS.  11 B- 11 C  depict a partial front view of the device  900 , illustrating an example operation of the ambient light sensor  922 . As noted above, the ambient light sensor  922  detects and/or senses ambient light (e.g., a color, color temperature, intensity, or other property of the light in the environment external to the device  900 ) through a display stack as well as through one or more electrode layers on or integrated with the display stack. However, the display stack emits light in order to produce graphical outputs. Because the ambient light sensor  922  detects light conditions through the display, the light from the display may interfere with or prevent accurate readings of the ambient light conditions. Accordingly, the ambient light sensor  922  may be configured to capture measurements during a time when the pixels over the ambient light sensor  922  are not illuminated. In particular, when producing graphical outputs, the display may produce a vertical blanking interval  1122 , which is a horizontal region of the display in which the pixels are not illuminated or producing light. The vertical blanking interval  1122  scrolls vertically along the display area (e.g., from a top of the display to a bottom of the display). Accordingly, the ambient light sensor  922  may be configured to capture measurements or samples over a duration that includes a time when the vertical blanking interval  1122  is positioned over the ambient light sensor  922 . While the instant discussion refers to a vertical blanking interval  1122  by way of example, other types of blanking intervals may also be used, including regions of inactive pixels that are included in the frames of the graphical output solely for the purpose of providing an inactive area for ambient light sensing. 
       FIG.  11 B  illustrates the device  900  with the display  1102  producing a graphical output  1120  and the vertical blanking interval  1122  moving downward as indicated by arrow  1124 . At this point in time, the vertical blanking interval  1122  is not positioned above the ambient light sensor  922 . Rather, the display pixels above the ambient light sensor  922  are active and/or producing light (e.g., to output the graphical output  1120 ). Accordingly, the ambient light sensor  922  may be in an inactive state or otherwise not capturing or using ambient light measurements during this time. 
       FIG.  11 C  illustrates the device  900  at a time when the vertical blanking interval  1122  is positioned directly over the ambient light sensor  922 . The ambient light sensor  922  may capture measurements during this time when the vertical blanking interval  1122  is positioned over the ambient light sensor  922  (or otherwise activate or use readings captured during this time). In some cases, the sensing window of the ambient light sensor  922  (e.g., the time that the ambient light sensor  922  is actively measuring or using measurements of light through the display) is greater than the vertical blanking interval  1122 . For example, the sensing window may begin and/or end while at least some of the pixels above the ambient light sensor  922  are active. In some cases, the time that the vertical blanking interval  1122  is above the ambient light sensor  922  is more than about 70% of the sensing window of the ambient light sensor  922  (or more than about 80%, more than about 85%, or any other suitable value). The device  900  may synchronize the operation of the ambient light sensor to the timing and/or position of the vertical blanking interval  1122  to allow the ambient light measurements to be captured at an appropriate time. The operation of the ambient light sensor  922  may be intermittent, such that it is only actively capturing measurements during the sensing window, and is inactive at other times. In other cases, the operation of the ambient light sensor  922  is capturing measurements more continuously, but the device  900  and/or the ambient light sensor  922  only uses values captured during the sensing window. 
     In some cases, the device  900  also compensates for the light emitted by the display in the area around the ambient light sensor  922 . For example, even when capturing measurements through the vertical blanking interval  1122 , light from nearby active pixels (e.g., a subset of the pixels of the display) may be incident on or otherwise detectable by the ambient light sensor  922 , thereby giving inaccurate measurements of the ambient light conditions. Accordingly, for ambient light measurements captured during a particular sensing window, the device  900  and/or ambient light sensor  922  may subtract or otherwise modify the light measurements based at least in part on the light being emitted by the pixels in an area  1125  surrounding the ambient light sensor  922 . The area  1125  may correspond to an n×m grid of pixels, and may be positioned above the ambient light sensor  922  (optionally centered above the ambient light sensor  922 ). In some cases, the grid of pixels is 256×256 pixels centered about the center of the hole  1105 , though other sizes and alignments are also possible depending on, for example, the size of the ambient light sensor, the size of the pixels, the location of the ambient light sensor relative to the active area of the display, the extent to which the light from nearby pixels is detectable by the ambient light sensor, and the like. The size of the area  1125  may be larger than the hole  1105 . Thus, the area  1125  includes a first subset of pixels that are positioned over the hole  1105 , and a second subset of pixels that are positioned remote from the hole  1105 . 
     Using the foregoing techniques, the ambient light sensor  922  receives light passing through the front cover  1100  and through the display  1102  (e.g., the display layers of the display  1102 ), and, while the blanking interval is positioned over the ambient light sensor  922 , produces an output corresponding to the received ambient light. The device may then determine an ambient light value based at least in part on the output. The device may change a display parameter of the display stack based at least in part on the ambient light value. For example, the device may change a brightness, a color temperature, or the like, or determine whether to activate or deactivate the entire display (e.g., turn the display on or off). 
     As noted above, the ambient light sensor  922  may also be capturing ambient light measurements through one or more electrode layers that are on or integrated with the display stack. The electrode layers may be used for any of various purposes, such as touch sensing, force sensing, display functionality, or the like. While the electrodes may appear transparent to the unaided eye, they may interfere with the light sensing functionality of the ambient light sensor  922  (e.g., by blocking, occluding, attenuating, or otherwise interfering with the ambient light that is detected by the ambient light sensor  922 ).  FIGS.  12 A- 12 B  depict example arrangements of electrodes on electrode layers to reduce or eliminate the impact of the electrodes on the ambient light sensing functionality. 
       FIG.  12 A , corresponding to area  12 - 12  in  FIG.  9 A , shows an example electrode pattern over the ambient light sensor  922 . In particular,  FIG.  12 A  illustrates how electrodes may be co-located in an area above the ambient light sensor  922 . For example, electrodes in areas outside of the ambient light sensor  922 , such as electrodes  1200 - 1  and  1202 - 1  may be set apart from one another, and electrodes along a portion  1204  of the display that corresponds to or includes the ambient light sensor  922 , such as electrodes  1200 - 2  and  1202 - 2 , are co-located (e.g., layered on or over one another). As shown in  FIG.  12 A , the electrodes in the portion  1204  of the display are co-located along an entire length of the display (e.g., from the top of the display to the bottom of the display). In implementations where electrodes are instead or also positioned horizontally or along a different direction, the electrodes extending over the ambient light sensor  922  may also be co-located along the entire display. In some cases, all of the electrodes in the display are co-located in the manner shown in the portion  1204 . 
       FIG.  12 B  illustrates an example in which electrodes that are positioned over the ambient light sensor  922  are co-located with one another where they are over the ambient light sensor  922 , but are set apart from one another in other areas of the display. For example, where electrodes  1200 - 3  and  1202 - 3  are positioned over the ambient light sensor  922 , they are co-located, but they jog apart in an area outside of the ambient light sensor  922  such that they are set apart. 
     The electrodes  1200 -n and  1202 -n may be positioned on different substrates or the same substrate. In some cases, the electrodes  1200 -n are positioned on a top surface of a substrate, and the electrodes  1202 -n are positioned on a bottom surface of the same substrate. In some cases, the electrodes  1200 -n and  1202 -n are on the same surface of the same substrate. In some cases, the electrodes  1200 -n and  1202 -n are each on different substrates. 
     While  FIGS.  12 A- 12 B  illustrate two sets of electrodes, there may be more sets of electrodes than shown. Further, the electrodes  1200 -n and  1202 -n are shown as different electrodes for the purpose of illustration, but in an implementation they may be different electrodes of a single set of otherwise identical electrodes. As noted above, the electrodes may provide various different types of functionality, including touch and/or force sensing (e.g., capacitive sensing, resistive sensing, etc.), display functionality, or the like. The electrodes may be formed from any suitable material, such as indium tin oxide (ITO), transparent conductive oxides (TCO), conductive polymers, nanowire layers (e.g., silver nanowire), or the like. 
       FIG.  13 A  depicts a partial cross-sectional view of an example electronic device  1300 , viewed along line  13 A- 13 A in  FIG.  1 A . The electronic device  1300  may correspond to or be an embodiment of the electronic devices  100 ,  140 ,  200 ,  300 , or any other device described herein. 
     The device  1300  may include a housing member  1302 , which may correspond to or be an embodiment of the housing member  130 . The housing member  1302  may also represent other housing members of the devices described herein, such as the housing members  124 ,  125 ,  126 ,  127 , and  128 . The housing member  1302  may define an exterior side surface  1303  of the device  1300 . The device  1300  may also include a cover  1304 , which may correspond to or be an embodiment of the cover  102  of  FIGS.  1 A- 1 B  (or any other cover described herein). The cover  1304  may define a front exterior surface  1306  of the device  1300 , which may be planar. In some cases, the cover  1304  defines a chamfer  1305  that extends around the periphery of the planar front exterior surface  1306  and extends between an edge of the front exterior surface  1306  and an edge of a side surface  1307  of the cover  1304 . The device  1300  may also include a rear cover  1309 , which may correspond to or be an embodiment of the rear cover  132  (or any other rear cover described herein). 
     The cover  1304  may be positioned over a display stack  1308 , which may correspond to or be an embodiment of the display  103  of  FIG.  1 A  (or any other display described herein). The display stack  1308  may be coupled to the cover  1304  along an interior surface of the cover  1304  via an adhesive  1310 , which may be a transparent adhesive. The adhesive  1310  may have a thickness, such as about 100 microns, 200 microns, about 300 microns, about 400 microns, or the like. 
     The display stack  1308  may include a display element  1312 , which may be configured to produce graphical outputs. The display element  1312  may be an OLED display, and may include multiple layers and/or other components that facilitate the production of graphical outputs, including, for example, substrates, an anode, a cathode, one or more organic layers, an emissive layer, adhesives, and the like. In some cases, the display element  1312  may include an integrated (on-cell) touch-sensing system, as described above. For example, an array of electrodes that are integrated into the OLED display may be time and/or frequency multiplexed in order to provide both display and touch-sensing functionality. In other cases, separate touch- and/or force-sensing systems may be included above or below the display element  1312  (each of which may include, for example, capacitive electrode layers, compliant layers, and the like). While an OLED display is described, the display element may be any suitable type of display, such as an LCD display, an active layer organic light emitting diode (AMOLED) display, an organic electroluminescent (EL) display, an electrophoretic ink display, or the like. 
     The display stack  1308  may include various electrically active layers and components that need to be electrically interconnected to other electrical components, processors, circuit elements, and the like. Because such layers (e.g., anode and cathode layers of an OLED display) may be sandwiched between other layers of the display stack  1308 , a flexible circuit element  1322  (e.g., a flexible circuit board) may wrap around a side of the display stack  1308  (forming a loop) to electrically couple the electrically active layers of the display stack  1308  to a more accessible circuit element  1320  of the display stack  1308 . More particularly, the flexible circuit element  1322  may include conductive traces that interconnect electrical components within the display element  1312  (e.g., cathode and anode layers, electrode layers of touch and/or force sensors, on-cell touch-sensing layers, etc.) to other electrical traces, connectors, processors, or other electrical components that are mounted on the circuit element  1320 . The circuit element  1320  may be a rigid or flexible circuit board. In some cases, a first encapsulating structure (e.g., an epoxy, foam, or other material or component) may be provided in the loop area  1316  between the side of the display stack  1308  and the flexible circuit element  1322  to help provide structure to the flexible circuit element  1322  and to help prevent deformation of the flexible circuit element  1322  due to impacts or other damage. For example, a first encapsulating structure  1317  (also referred to as a potting material) may be provided in the inside of the loop area  1316  to help provide structure to the flexible circuit element  1322  at the loop area  1316  and to help prevent deformation of the flexible circuit element  1322  due to drops, impacts, or the like. For example, if the device  1300  is dropped on the housing member  1302 , the housing member  1302  could force a frame member  1324  against the loop area  1316  of the flexible circuit element  1322 . The first encapsulating structure  1317  may help prevent such impacts from breaking, pinching, bending, deforming, or otherwise damaging the flexible circuit element  1322  at the loop area  1316 . 
     In some cases, in addition to or instead of providing the first encapsulating structure  1317  in the loop area  1316 , a second encapsulating structure  1340  may be provided in a region  1357  between the frame member  1324  and a loop  1335  of the flexible circuit element  1322 . The loop  1335  may define a convex outer surface and a concave inner surface, as shown in  FIG.  13 A . The second encapsulating structure  1340  may be an epoxy, foam, or other material or component, and may be unitary with the first encapsulating structure  1317  (e.g., they may both be formed during a single injection process of a single curable material), or it may be distinct from the first encapsulating structure  1317  (e.g., the first and second encapsulating structures may be introduced separately, such as in two subsequent injection operations). 
     The second encapsulating structure  1340  may provide several benefits. For example, the second encapsulating structure  1340  may reinforce the loop  1335  of the flexible circuit element  1322 . More particularly, the second encapsulating structure  1340  may reduce the likelihood that the flexible circuit element  1322  will be deformed or otherwise damaged due to an impact or other type of shock event. The second encapsulating structure  1340  may also improve the strength of the bond between the cover  1304 , the display stack  1308 , and the frame member  1324 . For example, the second encapsulating structure  1340  may have an adhesive property such that the second encapsulating structure  1340  adheres to the flexible circuit element  1322 , the cover  1304 , and the frame member  1324 , thereby bonding these components together via an adhesive bond. The physical shapes of the frame member  1324  and the loop  1335  of the flexible circuit element  1322  may also provide a mechanical interlock that retains the frame member  1324  and the display stack  1308  to the cover  1304 . For example, the frame member  1324  defines a flange portion  1329  which forms an undercut region that the second encapsulating structure  1340  fills and/or engages. Similarly, the second encapsulating structure  1340  wraps under the loop  1335  to engage the flexible circuit element, and the display stack  1308  more generally. Due to the way in which the second encapsulating structure  1340  engages these components, the adhesion between the second encapsulating structure  1340  and the cover  1304  helps retain the frame member  1324  and display stack  1308  to the cover  1304 . 
     In some cases, the additional attachment security provided by the second encapsulating structure  1340  may facilitate the use of less adhesive  1326  to attach the frame member  1324  to the cover  1304 , and thereby allow a thinner adhesive layer  1310 , which ultimately reduces the overall thickness of the display stack and can provide more room inside the device for other components (e.g., a battery), and/or allow the device to be made thinner. More particularly, the increased attachment strength provided by the second encapsulating structure  1340  may facilitate the use of a smaller glue region for the adhesive  1326 , and thus the flange portion  1329  can extend a smaller distance towards the display (e.g., it is shorter in a left-to-right direction, as shown in  FIG.  13 A ). By making the flange portion  1329  smaller in this direction, the display stack can be placed closer to the cover  1304  without the loop  1335  contacting or being too close to the flange portion  1329 , thereby allowing a thinner layer of adhesive  1310  between the display element  1312  and the cover  1304 . 
     The encapsulating structures may also provide an environmental seal that supplements the seal provided by the adhesive  1326 . For example, if an impact or other damage were to compromise the adhesion between the adhesive  1326  and the cover  1304  and/or the frame member  1324 , the first and second encapsulating structures may continue to inhibit or prevent liquids or other contaminants from reaching and damaging the display stack or other sensitive components of the device. 
     The display stack  1308  may include other components in addition to the display element  1312  and touch- and/or force-sensing components, such as support and shielding layers, and adhesive layers to hold the various components of the display stack  1308  together. For example, the display stack  1308  may include a first metal plate  1314  that supports the display element  1312  and imparts structural support, rigidity, and flatness to the display element  1312 . The first metal plate  1314  may have the same or substantially the same front-facing area as the display element  1312  (e.g., the first metal plate  1314  may have a front-facing area that is greater than 90% of the display element  1312 ). The display stack may also include a second metal plate  1318  that supports the circuit element  1320 . The second metal plate  1318  may have a smaller frontal area than the first metal plate  1314 , and may have a size that is similar to the circuit element  1320 . Both the circuit element  1320  and the second metal plate  1318  may have a front-facing area that is less than 50% of the front-facing area of the display element  1312 , and optionally less than 30% of the front-facing area of the display element  1312 . 
     The display stack  1308  may include other layers and components, as well. For example, the display stack  1308  may include adhesives between various layers and elements in the display stack  1308 . More specifically, the display stack  1308  may include an adhesive between the display element  1312  and the first metal plate  1314 , an adhesive between the first metal plate  1314  and the second metal plate  1318 , and an adhesive between the second metal plate  1318  and the circuit element  1320 . Of course, other layers, sheets, substrates, adhesives, and/or other components may also be included in the display stack  1308 . 
     The cover  1304  may be attached to a frame member  1324 . The frame member  1324  may be formed from or include a polymer material, and may extend around all or substantially all of a perimeter of the cover  1304 . The frame member  1324  may at least partially encapsulate and/or otherwise be coupled to a back plate  1328 . The back plate  1328  may be formed of or include metal, plastic, or any other suitable material. The back plate  1328  may provide shielding and structural support to the device, and may protect the display stack  1308  by forming an at least partially enclosed area in which the display stack  1308  is positioned. The back plate  1328  may be at least partially encapsulated in the frame member  1324 , or it may be attached to the frame member  1324  in any other suitable manner. 
     The frame member  1324  may be attached to the housing member  1302 . For example, the frame member  1324  may be attached to a ledge  1323  or other feature defined by the housing member, as depicted in  FIG.  13 A . The ledge  1323  may extend from an interior side of the housing member  1302 . The ledge  1323  may be part of a monolithic structure of the housing member  1302  (e.g., the housing member may be molded, machined, or otherwise formed from a single piece of material to define the ledge  1323  as well as the other features and/or surfaces of the housing member  1302 ). The frame member  1324  may be attached to the housing member  1302  via an adhesive  1325 , which may be between and in contact with the ledge  1323  and the frame member  1324 . The adhesive  1325  may be any suitable adhesive, such as a pressure sensitive adhesive (PSA), heat sensitive adhesive (HSA), adhesive film, epoxy, or the like. In some cases, the ledge or other feature to which the frame member  1324  is attached acts as a datum surface for the frame member  1324 . Thus, the alignment (e.g., flushness) of the front exterior surface  1306  of the cover  1304  and the upper portion  1332  (e.g., the front exterior surface) of the housing member  1302  may be defined or established by the location of the ledge (relative to the upper portion  1332 ), as well as the location of the bottom surface of the frame member  1324  (relative to the front exterior surface  1306  of the cover  1304 ). 
     The cover  1304  may be attached to the frame member  1324  via an adhesive  1326 . The frame member  1324  may define a recessed region  1327  (which defines a bonding surface), and the adhesive  1326  may be placed in the recessed region  1327 . The recessed region  1327  may provide a trough-like volume for the adhesive  1326 , while also allowing a flange portion  1329  of the frame member  1324  to contact the underside of the cover  1304 . The direct contact between the flange portion  1329  of the frame member  1324  and the cover  1304  may provide a rigid connection between the cover  1304  and the frame member  1324  and may ensure that forces applied to the cover  1304  are transferred to the structural frame member  1324 . While the recessed region  1327  is defined by a single flange portion  1329  (e.g., on the right side of the recessed region  1327 ), other configurations are also possible, such as a recessed region defined by two flange portions or other sidewall-like features (e.g., a channel defined by two walls). 
     The housing member  1302  may be specifically configured to allow a close coupling between it and the assembly that includes the cover  1304 , the display stack  1308 , and the frame member  1324 . In particular, the housing member  1302  may define a recessed region  1330  (also referred to simply as a recess) along an interior surface of the housing member  1302  that is adjacent or proximate the frame member  1324 . The recessed region  1330  may be formed into the housing member  1302  in any suitable way. For example, the recessed region  1330  may be machined into the housing member  1302 , or the housing member  1302  may be molded or cast and the recessed region  1330  may be formed as part of the casting or molding process. 
     The recessed region  1330  may correspond to a portion of the housing member  1302  that is thinner than other portions of the housing member  1302 . For example, the housing member  1302  may define an upper portion  1332  and a lower portion  1334  that have a greater thickness (in the left-to-right direction as depicted in  FIG.  13 A ) than the portion of the housing member  1302  that defines the recessed region  1330 . 
     The recessed region  1330  may be configured so that the interior surface of the housing member  1302  that is directly opposite the frame member  1324  is set apart from the frame member  1324  by a target distance. The target distance may be selected so that deformations or deflections of the housing member  1302  along the side wall (e.g., due to the device  1300  being dropped or otherwise subjected to predictable misuse or damage) do not contact the frame member  1324  and/or the display stack  1308 . More particularly, the recessed region  1330  allows the device  1300  to accommodate a certain amount of deformation of the side wall of the housing member  1302  without the housing member  1302  contacting the frame member  1324 . For example, the inner surface of the recessed region  1330  may be spaced apart from the outer peripheral surface  1331  of the frame member  1324  by about 0.3 mm, 0.5 mm, 0.7 mm, 1.0 mm, or any other suitable distance. In some cases, the distance between the inner surface of the recessed region  1330  and the outer surface of the frame member  1324  is greater than a housing deformation that is produced as a result of a standard test, such as a side impact test (e.g., in which the device  1300  is dropped from a certain height (e.g., 1 m, 2 m, or 3 m) onto a certain surface (e.g., an edge of a triangular prism). 
     In some cases, the height (e.g., the vertical direction as depicted in  FIG.  13 A ) of the recessed region  1330  (and optionally the height of the recessed region  1330  and the additional recessed region  1336  combined) is equal to or greater than a height of the frame member  1324 . In this way, the recessed region  1330  (optionally with the additional recessed region  1336 ) is large enough so that the frame member  1324  could extend at least partially into the recessed region  1330  in the event of an impact or drop (e.g., causing the housing member  1302  to deform or deflect), without the frame member  1324  contacting the housing member  1302 . This may help prevent damage to the frame-cover interface and help prevent separation of the cover  1304  from the frame member  1324  (e.g., by preventing or reducing the magnitude of forces applied to the frame member  1324  by the housing member  1302  in the event of an impact, drop, or the like). In some cases, the height of the recessed region  1330  (and optionally the recessed region  1330  combined with the additional recessed region  1336 ) extends from the ledge  1323  to a height or location that is at or above the bottom surface of the cover  1304 . 
     In some cases, the distance between the inner surface of the recessed region  1330  and the outer surface of the frame member  1324  is greater than a distance between a side surface  1307  of the cover  1304  and an inner side surface  1333 . Thus, for example, a deformation or deflection of the housing member  1302  towards the cover  1304  and the frame member  1324  may result in the side surface  1307  of the cover  1304  contacting the inner side surface  1333  of the frame member  1324  before the housing member  1302  (and in particular the inner surface of the recessed region  1330 ) contacts the frame member  1324 . Thus, by forming a recessed region  1330  that establishes a greater distance between the housing member  1302  and the frame member  1324  than the distance between the housing member  1302  and the cover  1304 , the risk of contact between the housing member  1302  and the frame member  1324  during deformation or deflection of the housing member  1302  may be reduced. 
     The side surface  1307  of the cover  1304  may abut an inner side surface  1333  of the housing member  1302  (or be adjacent the inner side surface  1333  without interstitial components, as described herein). In some cases, there is no interstitial component or other material between the side surface  1307  of the cover  1304  and the inner side surface  1333  of the housing member  1302 . This construction provides several structural and cosmetic advantages. For example, the lack of a bezel or other interstitial component or material between these surfaces provides a clean, frameless appearance to the front of the device  1300 . In particular, the front-facing surfaces of the device  1300  may be defined only by the upper portion  1332  of the housing member  1302  and the front exterior surface  1306  of the cover  1304 . While the side surface  1307  of the cover  1304  may abut an inner side surface  1333  of the housing member  1302 , in some cases an air gap may exist between these surfaces. In some cases, an adhesive or sealing material may be positioned between the side surface  1307  of the cover  1304  and the inner side surface  1333  of the housing member  1302 . In such cases, the adhesive or sealing material may be the only material between these surfaces, may be in contact with both surfaces, and may have a thickness less than about 0.5 mm, 0.3 mm, 0.1 mm, 0.05 mm, or any other suitable thickness. 
     The proximity between the side surface  1307  of the cover  1304  and the inner side surface  1333  of the housing member  1302  may define a load path through the upper portion  1332  of the housing member  1302  and into the cover  1304 . For example, forces applied to the exterior side surface  1303  of the housing member  1302  may be directed into the cover  1304  at the interface between the side surface  1307  of the cover  1304  and the inner side surface  1333  of the housing member  1302 . (In cases where the inner side surface  1333  abuts the side surface  1307  of the cover  1304 , loads may be directly transferred or directed into the cover  1304 , while in cases where there is an air gap between the inner side surface  1333  and the side surface  1307  of the cover  1304 , the forces may initially cause the gap to close such that the inner side surface  1333  comes into contact with the side surface  1307 .) The rigidity and structural integrity of the cover  1304  may help prevent or reduce deformation of the housing member  1302  in the event of a drop or other impact on the exterior side surface  1303 , thereby protecting internal components of the device  1300  from damage due to the housing member  1302  contacting them. By defining the load path through the cover  1304  and by configuring the housing member  1302  to include the recessed region  1330 , the device  1300  may be designed to omit the frame member  1324  from the load path during many impact events (e.g., the device  1300  being dropped). For example, as shown in  FIG.  6 A , the recessed region  1330  ensures that the frame member  1324  is set apart from the housing member  1302  by a suitable distance. Also, no portion of the frame member  1324  is between the housing member  1302  and the cover  1304 . Accordingly, the frame member  1324  may be positioned so that it is not contacted or impacted by the housing member  1302 , even if the housing member  1302  is subjected to an impact, deformed, deflected, or otherwise damaged (up to a certain amount of deformation or deflection). 
     In some cases, the rear cover  1309  interfaces with the lower portion  1334  of the housing member  1302 , in that the lower portion  1334  may contact a side surface of the rear cover  1309 , thereby defining a load path through the lower portion  1334  and into the rear cover  1309 . 
     In some cases, the housing member  1302  may include an additional recessed region  1336 . The additional recessed region  1336  may be configured so that the housing member  1302  in that region is set a distance away from components in the display stack  1308 , touch- and/or force-sensing components, antennas, or other electrical components of the device  1300 . In particular, as the housing member  1302  may be formed of metal, the metal may capacitively couple to other electronic components. By increasing the distance between the metal of the housing member  1302  and the electrical components, the capacitive coupling may be reduced to an acceptable level. Accordingly, the additional recessed region  1336  may be configured so that the distance between the additional recessed region  1336  and another electrical component is greater than about 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm, or any other suitable distance. In some cases, the recessed region  1330  may be recessed further (and thus correspond to a thinner portion of the housing member  1302 ) than the additional recessed region  1336 . 
       FIG.  13 B  depicts another example embodiment of the device  1300 , showing another configuration for the second encapsulating structure.  FIG.  13 B  omits the housing member  1302  and rear cover  1309  for simplicity. As shown in  FIG.  13 B , the second encapsulating structure  1358  does not fill the entire region  1357 . Rather, the second encapsulating structure  1358  is positioned in a corner region where the flange portion  1329  of the frame member  1324  meets the cover  1304 . The second encapsulating structure  1358  thus contacts and adheres to both the frame member  1324  and the cover  1304 , thereby contributing to the bond strength between those components. This implementation also provides an air gap between the loop  1335  and the frame member  1324 . 
       FIG.  13 C  depicts another example embodiment of the device  1300 , showing another configuration for the second encapsulating structure.  FIG.  13 C  omits the housing member  1302  and rear cover  1309  for simplicity. As shown in  FIG.  13 C , the second encapsulating structure  1343  extends around a portion of the loop  1335 , and compliant member  1342  is positioned between the flexible circuit element  1322  (or other component of the display stack  1308 ) and the back plate  1328 . The compliant member  1342  may be less rigid (e.g., more flexible and/or compressible) than the second encapsulating structure  1343 . The compliant member  1342  may absorb energy from impacts, pinches, or other force events that may tend to force the flexible circuit element  1322  and the back plate  1328  together, thereby reducing the amount or intensity of the force that ultimately contacts the flexible circuit element  1322 . The compliant member  1342  may be a compliant polymer, foam, elastomer, silicone, or any other suitable material. In some cases, the compliant member  1342  is adhesive and adheres to the flexible circuit element  1322  and/or the back plate  1328 . In some cases, the compliant member  1342  is adhered to the flexible circuit element  1322  and/or the back plate  1328  with a separate adhesive (e.g., a PSA, HSA, an adhesive film, a liquid adhesive, etc.). 
       FIG.  13 D  depicts a portion of the electronic device shown in  FIGS.  13 A- 13 C , illustrating another view of the location of the encapsulating structures, and how potting material may be introduced into the area around the loop  1335  of the flexible circuit element  1322  to form encapsulating structures.  FIG.  13 D  generally illustrates the frame member  1324  and the back plate  1328 , with the cover  1304  and display stack  1308  removed. The dashed line illustrates an example location of the loop  1335  of the display if the display stack  1308  and cover  1304  were attached. Further, while  FIG.  13 D  shows the cover and display removed, in some implementations the potting material is introduced with those components attached to the frame member  1324 . 
     In some cases, potting material  1360  (which may correspond to or produce the first encapsulating structure and/or the second encapsulating structure described with respect to  FIGS.  13 A- 13 C ) may be introduced into the region  1357  via an injection port  1362 . The potting material may be understood as being introduced into the injection port  1362  in a direction out of the page, by an injection device that is behind the frame member  1324 . Stated differently, the frame member  1324  as shown in  FIG.  13 D  would be flipped over during the injection process. 
     The potting material  1360  may be a curable polymer, such as an epoxy, that can be introduced as a liquid or other flowable state, and then allowed to cure. A vent port  1361  may allow air to escape from the region  1357  ( FIG.  13 A ) while the potting material is being introduced. In some cases, a vacuum or negative pressure is applied to the vent port  1361  to aid the flow of the potting material  1360  into the desired locations. As the loop  1335  of the flexible circuit element  1322  may be open on its ends, the potting material may flow into the loop area  1316  ( FIG.  13 A ) while the potting material  1360  is introduced through the injection port  1362 . 
     Barrier structures  1363 ,  1364 ,  1365 ,  1366 , and  1367  may define walls of the volume in which the potting material  1360  is positioned. The barrier structures may be positioned between (and may contact and/or be sandwiched by) the display stack and a back plate  1328 , or the cover  1304  and the back plate  1328 , or any other suitable components or structures. The barrier structures may include adhesives, foams, glues, structural portions of the frame member, or the like, and may have other functionalities in addition to acting as barriers to the potting material  1360 . For example, the barrier structure  1363  may correspond to the frame member  1324  and adhesive  1326 , and the barrier structures  1364  and  1356  may correspond to an adhesive structure (e.g., an adhesive foam) that is used to couple the frame member  1324  and/or back plate  1328  to the cover and/or display stack. The barrier structures  1366  and  1367  may correspond to an adhesive that bridges gaps between the barrier structures  1364  and  1365  and/or between other components of the device. 
     In some implementations, barrier structures, such as the barrier structures  1363  and  1364  define channel segments extending along corner regions  1347  of the frame member  1324 . During an injection process, the potting material  1360  may travel, within the channel segments, along the corner regions  1347 , and extending at least partially along a side of the frame member  1324  (e.g., along the long sides of the device and/or display). In some cases, a portion of either the barrier structure  1363  and/or  1364  (or a different component or material) may define an optional barrier  1371  that blocks the channel segment or otherwise defines a blind end of the channel segment, thereby limiting the flow path of the potting material  1360  during its introduction, ultimately assisting in defining the shape of the structure that is produced when the potting material  1360  hardens or cures. 
       FIGS.  13 A-C  illustrate example device configurations that include a frame member  1324  that is attached to a cover (and optionally coupled to a back plate  1328 ), and which is attached to a housing member (e.g., via an adhesive  1325 ) to secure the top module to the housing and/or other component(s) of the device. The frame member  1324  may be formed of or include plastic, metal, and/or other materials, and may be formed separately from the other components of the top module (e.g., the cover, the display stack, etc.), and then assembled with those components to form the top module.  FIG.  13 E  illustrates an example embodiment of the device  1300  in which a molded frame member  1370  is used instead of the frame member  1324 . More particularly, the molded frame member  1370  may be formed, after the display stack  1308  is attached to the cover  1304 , by molding a moldable material in place, and allowing the material to cure or otherwise harden to define the molded frame member  1370 . For example, the display stack  1308  may be attached to the cover  1304  to form a subassembly. That subassembly may then be placed in a mold that defines at least part of the shape of the molded frame member  1370 , and a moldable material (e.g. a polymer, reinforced polymer, thermoplastic polymer, thermoset polymer, epoxy, or the like) may be introduced into the mold. The material flows against the cover  1304  and the display stack  1308  (including against and around the loop  1335 ), and may adhere or bond to those components via mechanical or chemical bonds (or both). The material is allowed to cure or otherwise harden to form the molded frame member  1370 , and the subassembly with the molded frame member  1370  is removed from the mold. Optionally, a back plate is incorporated into the mold as well, and is at least partially encapsulated in the molded frame member  1370 . The top module may then be attached to the housing member  1302  by affixing the molded frame member  1370  to the housing member  1302  with adhesive  1325  (or via any other attachment technique). 
       FIG.  13 E  also illustrates the loop area  1316  having been filled with a potting material  1317 . In some cases, the potting material  1317  is part of the molded frame member  1370 . For example, when the moldable material for the molded frame member  1370  is introduced into a mold, the material may also flow into the loop area  1316 , thereby defining a unitary (monolithic) structure that acts as the molded frame member and the potting in the loop area  1316 . In some cases, the potting material  1317  is a separate material than that of the molded frame member  1370 , and is introduced into the loop area  1316  separately from the material that forms the molded frame member  1370  (e.g., before or after the molded frame member  1370  is molded in place). 
     The molded frame member  1370  can provide numerous advantages and benefits by combining the functions of a frame member and a potting material into a single component that can be manufactured in a single operation. For example, the molded frame member  1370  can perform the structural functions of a separate frame member, including providing structural rigidity to the top module and providing a structural attachment member to secure the cover  1304  to the housing member  1302  (or any other suitable structural component of the device. Further, the molded frame member  1370  can self-adhere to the cover  1304  during the molding operation, thereby reducing assembly operations and time as compared to separately manufacturing a frame member that then has to be attached to the cover  1304 . Additionally, the molded frame member  1370  can perform the same stabilizing function to the loop  1335  as the potting material  1340  ( FIG.  13 A ) or  1343  ( FIG.  13 C ), without requiring an additional potting operation (as is the case with potting materials introduced after a frame member is formed and attached). 
     While  FIG.  13 E  shows only a portion of the molded frame member  1370  that is positioned proximate the loop  1335  of the display, the molded frame member  1370  may extend around the entire periphery of the top module, effectively defining a frame along all four sides of the interior surface of the cover  1304 , and optionally at least partially encapsulating the display stack along multiple sides of the display stack. In some cases, the molded frame member  1370  extends around less than the entire periphery of the top module. 
     Other components, features, or other details of the device  1300  shown in  FIG.  13 E  are the same as or similar to those shown and described with respect to  FIGS.  13 A- 13 C , and those descriptions apply equally to those components, features, or other details shown in  FIG.  13 E . 
       FIG.  13 F  illustrates another example configuration of a device that may enable the use of a thinner adhesive to attach a display stack to a cover. For example,  FIG.  13 F  illustrates a partial cross-sectional view of a device with a cover  1378  with a thinned outer region  1380 . Except for the thinned outer region  1380 , the cover  1378  may be the same as or similar to the cover  1304 , and for brevity those details are not repeated here. The cover  1378  may be attached to a frame member  1374  via an adhesive  1376  that is positioned in a recessed region  1375  (which defines a bonding surface) of the frame member  1374 . The frame member  1374 , adhesive  1376 , and recessed region  1375  may be the same as or similar to the frame member  1324 , adhesive  1326 , and recessed region  1327 , and for brevity those details are not repeated here. 
     The thinned outer region  1380  may extend along one or more edges of the cover  1378 . For example, the thinned outer region  1380  may extend along one edge of the cover  1378 , and in particular, an edge of the cover  1378  that is proximate a flexible circuit element  1373  of the display stack  1382 . In some cases, the thinned outer region  1380  may extend along two, three, or four sides of the cover  1378 . For example, in the case of a substantially rectangular cover, the thinned outer region  1380  may extend around the entire outer periphery of the cover  1378  (e.g., the thinned outer region  1380  may extend around a display region of the cover  1378 , where the display region corresponds to a central region of the cover  1378  through which the display is visible and/or produces graphical outputs). The display stack  1382  and the flexible circuit element  1373  may be the same as or similar to the display stack  1308  and the flexible circuit element  1322 , and for brevity those details are not repeated here. 
     The thinned outer region  1380  may facilitate the use of a thinner layer of adhesive  1383  (e.g., optically clear or transparent adhesive) to attach the display stack  1382  to the cover  1378 . More particularly, the thinned outer region  1380  may allow a flange portion  1379  (similar to the flange portion  1329 ,  FIG.  13 A ) to be positioned further towards the exterior surface of the cover  1378  (e.g., higher in a vertical direction, as depicted in  FIG.  13 F ), such that the display stack  1382 , and thus the flexible circuit element  1373 , may likewise be positioned further towards the exterior surface of the cover  1378  without causing the flexible circuit element  1373  to contact or otherwise interfere with the flange portion  1379 . Accordingly, the thickness of the adhesive  1383  may be made thinner (e.g., relative to the adhesive  1310 ), resulting in an overall height of the display stack  1382  and cover  1378  that is less than a height of a device that does not include a cover with a thinned outer region (e.g., the overall height may be less than the overall height  1359  in  FIG.  13 A ). In some cases, the adhesive  1383  has a thickness of about 150 microns, about 125 microns, about 100 microns, or about 75 microns. 
     The thinned outer region  1380  of the cover  1378  may have a thickness  1381  of about 400 microns, and the main portion of the cover  1378  (e.g., the portion to which the display stack  1382  is attached and that includes the graphically active area of the device) may have a thickness of about 600 microns. In some cases, the thinned outer region  1380  is about 100 microns, about 200 microns, or about 300 microns thinner than the main portion of the cover  1378 . The thickness  1381  may be between about 375 microns to about 425 microns, and the thickness of the main portion may be between about 575 microns to about 625 microns. 
     The cover  1378  may define a transition region that extends from the thinned outer region  1380  to the main portion of the cover  1378 . For example, as shown in  FIG.  13 F , the transition region defines a curved portion of the bottom surface of the cover  1378  that extends from the thinned outer region  1380  to the main portion of the cover  1378 . The transition region (e.g., the surface of the transition region) may have a continuous curve (as shown), or it may have another shape or configuration. For example, the transition surface may be fully or partially planar, and may resemble a chamfered surface.  FIGS.  13 G- 13 L  illustrate other example shapes for a thinned outer region of a cover. 
       FIGS.  13 G- 13 L  illustrate example configurations of a thinned outer region for a cover. For example,  FIG.  13 G  illustrates a cover with a thinned outer region  1380 -G, similar to the thinned outer region shown in  FIG.  13 F . In this example, the thinned outer region  1380 -G includes or is defined by a flat region  1384 -G at the outer portion of the thinned outer region  1380 -G, and a curved region  1385 -G that extends from the flat region  1384 -G to a corner or edge  1386 -G. The corner or edge  1386 -G may represent an edge where the main portion  1389 -G of the cover (e.g., the planar surface to which a display stack is attached) meets the curved region, and may appear as a discontinuity or distinct apex. The curved region  1385 -G may define a concave surface shape, while the corner or edge  1386 -G may define a pointed convex feature. In cases where a cover that includes the thinned outer region  1380 -G is attached to a frame member, as shown in  FIG.  13 F , adhesive may be positioned on the flat region  1384 -G alone, the curved region  1385 -G alone, or on at least a portion of both the flat and curved regions. Further, a frame member (or other component) may contact the cover on the flat region  1384 -G and/or the curved region  1385 -G. 
       FIG.  13 H  illustrates a cover with a thinned outer region  1380 -H. In this example, the thinned outer region  1380 -H includes or is defined by a flat region  1384 -H at the outer portion of the thinned outer region  1380 -H, and a first curved region  1385 -H that extends from the flat region  1384 -H to a second curved region  1386 -H. In contrast to the corner  1386 -G, which may appear as a sharp to distinct apex or edge, the second curved region  1386 -H defines a curved profile. The first curved region  1385 -H may define a curved concave surface shape, and the second curved  1386 -H may define a curved convex surface shape. In some cases, the absolute values of the radii of curvature of the first and second curved regions are the same, while in other cases they are different from one another. The two curved regions defining the transition between the main portion  1389 -H and the thinned outer region of a cover may help eliminate sharp features (or other features) that can act as stress concentrating features, thereby increasing providing a strong cover that resists breaking or other damage. In cases where a cover that includes the thinned outer region  1380 -H is attached to a frame member, as shown in  FIG.  13 F , adhesive may be positioned on the surface(s) of the flat region  1384 -H, and/or either (or both) of the curved regions  1385 -H,  1386 -H. Further, a frame member (or other component) may contact the cover on the surface(s) of the flat region  1384 -H and/or either (or both) of the curved regions  1385 -H,  1386 -H. 
       FIG.  13 I  illustrates a cover with a thinned outer region  1380 -I. In this example, the thinned outer region  1380 -I includes or is defined by a flat region  1384 -I at the outer portion of the thinned outer region  1380 -I, and a step region  1385 -I defining a discontinuous transition from the thinned outer region  1380 -I to the main portion  1389 -I of the cover. The step region  1385 -I may define two substantially 90 degree corners, thus resulting in a step surface that is substantially perpendicular to the surface of the flat region  1384 -I and the main portion  1389 -I of the cover (as well as to an exterior surface of the cover), as shown in  FIG.  13 I . In other examples, the corners, and thus the step surface, may have different angles. For example, a corner between the flat region  1384 -I and the step surface may be about 80 degrees, and the corner between the step surface and the main portion  1389 -I of the cover may be about 100 degrees, resulting in a step surface that is about 80 degrees relative to the flat region  1384 -I (and the exterior surface of the cover). In cases where a cover that includes the thinned outer region  1380 -I is attached to a frame member, as shown in  FIG.  13 F , adhesive may be positioned on the surface(s) of the flat region  1384 -I, and/or the step surface of the step region  1385 -I. Further, a frame member (or other component) may contact the cover on the surface(s) of the flat region  1384 -I, and/or the step surface of the step region  1385 -I. 
       FIG.  13 J  illustrates a cover with a thinned outer region  1380 -J. In this example, the thinned outer region  1380 -J includes or is defined by a curved transition region  1387 -J extending from the main portion  1389 -J of the cover to the outer peripheral edge of the thinned outer region  1380 -J. The curved transition region  1387 -J may define a continuous concave curved profile, which may meet the main portion  1389 -J of the cover at a corner or edge  1319 -J. More particularly, the corner or edge  1319 -J may represent an edge where the main portion  1389 -J of the cover (e.g., the planar surface to which a display stack is attached) meets the curved transition region  1387 -J, and may appear as a discontinuity or distinct apex. The curved transition region  1387 -J may have a constant radius of curvature (e.g., it defines a portion of a circle), or a variable radius of curvature (e.g., it may define a non-circular spline). In cases where a cover that includes the thinned outer region  1380 -J is attached to a frame member, as shown in  FIG.  13 F , adhesive may be positioned on the surface(s) of the curved transition region  1387 -J. Further, a frame member (or other component) may contact the cover on the surface(s) of the curved transition region  1387 -J. 
       FIG.  13 K  illustrates a cover with a thinned outer region  1380 -K. In this example, the thinned outer region  1380 -K includes or is defined by a flat transition region  1387 -K extending from the main portion  1389 -K of the cover to the outer peripheral edge of the thinned outer region  1380 -K. The flat transition region  1387 -K may define a substantially planar surface, which may meet the main portion  1389 -K of the cover at a corner or edge  1319 -K. More particularly, the corner or edge  1319 -K may represent an edge where the main portion  1389 -K of the cover (e.g., the planar surface to which a display stack is attached) meets the flat transition region  1387 -K, and may appear as a discontinuity or distinct apex. In cases where a cover that includes the thinned outer region  1380 -K is attached to a frame member, as shown in  FIG.  13 F , adhesive may be positioned on the surface(s) of the flat transition region  1387 -K. Further, a frame member (or other component) may contact the cover on the surface(s) of the flat transition region  1387 -K. 
       FIG.  13 L  illustrates a cover with a thinned outer region  1380 -L, where the thinned outer region is inset from the outer peripheral edge of the cover. More particularly, the thinned outer region  1380 -L includes or is defined by a recess  1390  formed between a main portion  1389 -L of the cover, and a peripheral ridge  1388 . The thickness of the cover at the main portion  1389 -L and at the peripheral ridge  1388  (e.g., the thickness corresponding to the thickest dimension in these locations) may be equal, or they may be different. In cases where a cover that includes the thinned outer region  1380 -L is attached to a frame member, as shown in  FIG.  13 F , adhesive may be positioned on the surface(s) of the peripheral ridge  1388  and/or the recess  1390 . Further, a frame member (or other component) may contact the cover on the surface(s) of the peripheral ridge  1388  and/or the recess  1390 . 
     As noted above, the reduced thickness regions of the covers shown in  FIGS.  13 F- 13 L  may allow a display stack to be positioned closer to the interior surface of a cover, such as by allowing the use of thinner adhesives or other layers between the display stack and the cover. In some cases, the particular thicknesses of the thinned region and the main region of a cover may depend at least in part on a target thickness for an adhesive layer between the display stack and the cover, or other dimensions and/or other shapes or configurations of the display stack. In each of the covers shown in  FIGS.  13 F- 13 L , the thickness  1399  of the thinned outer region may be about 400 microns, and the thickness of the main portion of the cover (e.g., the portion to which the display stack is attached and that includes the graphically active area of the device) may have a thickness of about 600 microns. In some cases, the thickness  1399  of the thinned outer region may be about 100 microns, about 200 microns, or about 300 microns thinner than the main portion of the cover. The thickness  1399  may be between about 375 microns to about 425 microns, and the thickness of the main portion may be between about 575 microns to about 625 microns. In some cases, the thickness  1399  may be about 10%, about 20%, about 30%, about 40%, or about 50% thinner than the thickness of the main portion of the cover. The thicknesses  1399  may correspond to a thickness dimension of the cover as measured between the thinnest portion of a thinned outer region, as illustrated in  FIGS.  13 G- 13 L . 
     The covers shown in  FIGS.  13 F- 13 L  may be formed in various ways. For example, the covers, including the thinned outer regions  1380 , may be formed by molding (e.g., heating glass or another transparent material and applying a mold or press to produce the desired shape), machining (e.g., grinding, lapping, or otherwise removing material from a sheet to form the desired shape), and/or by additive manufacturing (e.g., adhering, bonding, or otherwise attaching a first glass sheet to a second glass sheet to form the desired shape). Combinations of these processes may also be used to form the covers and produce the thinned outer regions. 
       FIG.  13 M  illustrates an example cover and frame member configuration in which an adhesive  1321  that attaches a display stack  1392  to a bottom or interior surface of a cover  1304  defines an angled ramp surface  1391  that deflects a portion of the display stack  1392  downwards (e.g., away from the front cover) to help prevent or reduce the risk of contact between the display stack and the frame member  1324 . The angled ramp surface  1391  may be configured to deflect the loop  1337  of the flexible circuit element of the display stack, as well as a portion of the layered region  1339  of the display stack  1392  (optionally including an active region of the display that is configured to produce graphical outputs). The angled ramp surface  1391  may be unitary with the rest of the adhesive layer that attaches the display stack  1392  to the cover  1304  (e.g., the angled ramp surface  1391  may be a thickened region of the adhesive  1321 ). In some cases, the adhesive  1321  is a liquid optically clear adhesive (LOCA) that is dispensed on the cover  1304  and/or the display stack  1392  to define a substantially uniform-thickness portion (e.g., region  1393 ) that is positioned over an active area of the display, and the angled ramp surface  1391 . 
     The angled ramp surface  1391  is configured to deflect the loop  1337  and a portion of the layered region  1339  of the display stack  1392  away from the cover  1304  (e.g., downward as shown in  FIG.  13 M ). The angled ramp surface  1391  may have a curved or flat surface (e.g., the surface that contacts the display stack  1392 ) and may have a maximum thickness of between about 100 microns and about 200 microns. 
       FIG.  13 N  depicts another example configuration for attaching a cover and display stack to the housing member  1302 . In the example shown in  FIG.  13 N , a display stack  1396  is attached to an interior surface of a cover  1304  via an adhesive  1394  (e.g., an optically clear adhesive). A mounting plate  1397  is attached to the display stack  1396  via adhesive  1395  and/or other attachment techniques (e.g., fasteners, brackets, etc.). The mounting plate  1397  is attached to a housing member  1302  to secure the cover  1304  and display stack  1396  (also referred to as a top module) to the housing member  1302 . More particularly, the mounting plate  1397  may be attached to a ledge  1323  of the housing member  1302  via an adhesive  1398  (e.g., an HSA, TSA, adhesive foam, epoxy, etc.). In some cases, the attachment between the mounting plate  1397  and the ledge  1323  with the adhesive  1398  may be the only attachment between the top module and the housing member  1302 . In other cases, the top module is further secured to the housing member  1302  in other ways as well, such as with fasteners (e.g., screws, bolts, rivets), interlocking features, latching features, brackets, or the like. 
     The ledge  1323  may be part of a single unitary structure that also defines the side wall of the housing member  1302 . For example, the housing member  1302  may be formed of metal, plastic, or the like, and may define a side wall of the housing as well as the ledge  1323 . In other cases, the ledge  1323  may be a different component that is attached to or otherwise integrated with a portion of the housing member  1302  that defines the side wall. For example, the ledge  1323  may be part of a polymer material (e.g., fiber-reinforced polymer) that is molded against a metal housing structure. Other configurations and constructions for the ledge  1323  are also contemplated. 
     The configuration shown in  FIG.  13 N , in which the mounting plate  1397  is used to attach the top module to the housing member  1302 , allows the top module to be attached to the housing member  1302  without a frame member (e.g., without the frame member  1324  shown in  FIGS.  13 A- 13 C,  13 F, and  13 M ). The lack of the frame member may provide greater clearance between the display loop and/or other portions of the display stack  1396  and other components of the device (e.g., the housing member  1302 ). Alternatively, the display loop may be positioned closer to the housing member  1302 , thereby facilitating a larger active area of the display screen, a smaller device, or both. Further, by omitting the frame member, the display stack  1396  may be positioned closer to the interior surface of the cover  1304 , as there is no portion of the frame member (e.g., no flange) that interferes with or otherwise limits the vertical positioning of the display stack  1396  relative to the cover  1304 . More broadly, removing the frame member as shown in  FIG.  13 N  may produce a more space-efficient device in the x, y, and/or z directions. 
     While  FIG.  13 N  shows only a portion of the mounting plate  1397  and housing member  1302  proximate the loop of the display stack  1396 , the same or similar configuration of the housing  1302  (including the ledge  1323 ), the mounting plate  1397 , and the adhesive  1398  may extend around the entire periphery of the top module, effectively defining an adhesive mounting area along all four sides of the device. In some cases, the mounting plate  1397  and adhesive  1398  extend around less than the entire periphery of the top module. 
     As noted above, devices as described herein may include one or more groups of antennas that include elements that are configured to communicate via a 5G wireless protocol (including millimeter wave and/or 6 GHz communication signals).  FIG.  14 A  depicts a portion of an electronic device  1400 , with components removed to better illustrate example antenna groups for 5G wireless communications. 5G communications may be achieved using various different communications protocols. For example, 5G communications may use a communications protocol that uses a frequency band below 6 GHz (also referred to as the sub-6 GHz spectrum). As another example, 5G communications may use a communications protocol that uses a frequency band above 24 GHz (also referred to as the millimeter-wave spectrum). Further, the particular frequency band of any given 5G implementation may differ from others. For example, different wireless communications providers may use different frequency bands in the millimeter-wave spectrum (e.g., one provider may implement a 5G communications network using frequencies around 28 GHz, while another may use frequencies around 39 GHz). The particular antenna group(s) implemented in a device as described herein may be configured to allow communications via one or multiple of the frequency bands that implement 5G communications. 
     The device  1400  in  FIG.  14 A  includes at least two groups of antennas, each configured to operate to provide 5G communications using a different communications protocol. For example, the first antenna group includes multiple antennas to communicate via the sub-6 GHz spectrum, and the second antenna group includes multiple antennas to communicate via the millimeter-wave spectrum. 
     As noted above, the housing members of a device, such as a mobile phone, may be adapted for use as antennas. In the device  1400 , for example, the housing  1450  may include housing members  1401 ,  1403 ,  1405 ,  1407 ,  1409 , and  1411 . These housing members may be formed from metal or another conductive material, and may be electrically coupled to communications circuitry (as described in greater detail herein) in order to cause portions of the housing members to send and/or receive wireless communications. The housing members  1401 ,  1403 ,  1405 ,  1407 ,  1409 , and  1411  may be coupled together with joining elements  1416 ,  1418 ,  1420 ,  1422 ,  1424 , and  1426  to form the housing members into a single structural housing component. For simplicity, the joining elements  1416 ,  1418 ,  1420 ,  1422 ,  1424 , and  1426  are shown as being separate components, though some of the joining elements may be contiguous (e.g., the joining elements  1416  and  1418  may be parts of a contiguous molded polymer structure). 
     The joining elements may both mechanically and/or structurally couple the housing members together, and provide electrical isolation between adjacent housing members to facilitate the use of the housing members as radiating antennas. More particularly, with respect to the mechanical coupling, a joining element may securely attach to adjacent housing members (e.g., via mechanical interlocks between the joining element and the housing members and/or via adhesive or chemical bonds between the joining element and the housing members). With respect to the electrical isolation functions, a joining element may provide a requisite electrical isolation between an antenna and another conductive component (e.g., another conductive housing member, whether acting as an antenna or a non-radiating structural member) to reduce attenuation of the antenna performance (e.g., due to capacitive coupling between the antenna and the other conductive component). The joining elements may be formed from or include a nonconductive and/or dielectric material, such as a polymer, fiber-reinforced nylon, epoxy, or the like. Thus, the joining elements may be referred to herein as nonconductive joining elements. 
     The joining elements may be formed by a molding process. For example, the housing members may be placed into a mold or otherwise maintained in a fixed position relative to one another such that gaps are defined between adjacent housing members. One or more polymer materials may then be injected into the gaps (and optionally into engagement with retention structures and/or interlock features defined in the housing members), such that the polymer materials at least partially fill the gaps, and allowed to cure or otherwise harden to form the joining elements. In some cases, joining elements may be formed from multiple different materials. For example, an inner portion of the joining element may be formed of a first material (e.g., a polymer material), and an outer portion of the joining element (e.g., that defines part of the exterior surface of the housing) may be formed of a second material that is different from the first (e.g., a different polymer material). The materials may have different properties, which may be selected based on the different functions of the inner and outer portions of the joining elements. For example, the inner material may be configured to make the main structural connection between housing members, and may have a higher mechanical strength and/or toughness than the outer material. On the other hand, the outer material may be configured to have a particular appearance, surface finish, chemical resistance, water-sealing function, or the like, and its composition may be selected to prioritize those functions over mechanical strength. The joining elements may be formed from fiber-reinforced polymer, epoxy, or any other suitable material(s). 
     In the device  1400 , at least three segments of the housing are adapted for use as antennas for communicating via the sub-6 GHz spectrum. More particularly, the housing members may be adapted for use as antennas by conductively coupling ground lines and feed lines to particular locations on the housing members (which are conductive and may be formed of or include metal). The particular location of the ground and feed lines on a housing member may in part define the particular wavelengths for which the antennas are tuned. 
     The device  1400  includes one example configuration of a first group of antennas for communicating via the sub-6 GHz spectrum. The first group of antennas includes a first sub-6 GHz antenna  1402 , a second sub-6 GHz antenna  1404 , a third sub-6 GHz antenna  1406 , and a fourth sub-6 GHz antenna  1408 . In this example configuration, the first, second, and third sub-6 GHz antennas  1402 ,  1404 ,  1406  are defined by segments of housing members, while the fourth sub-6 GHz antenna  1408  is a conductive trace (e.g., on a circuit board) or other radiating element that is positioned within the device. The four antennas of the first group of antennas may be configured to operate according to a 4×4 MIMO (multiple input, multiple output) scheme. 
     The antennas that are defined by segments of the housing members may be similar to one another in structure and function. Accordingly, to avoid redundancy, only the first sub-6 GHz antenna  1402  will be described in detail. However, it will be understood that the description applies equally to the second sub-6 GHz antenna  1404  and the third sub-6 GHz antenna  1406  as well. 
     The first sub-6 GHz antenna  1402  may be defined by a portion of the housing member  1401 , and more particularly, a portion of the housing member  1401  that is proximate the joining element  1416 . In order to send and receive electromagnetic signals from the first sub-6 GHz antenna  1402 , ground and feed lines may be conductively coupled to the housing member  1401 . For example, a ground line may be conductively coupled to location  1412  and a feed line may be conductively coupled to location  1410 . 
     The portion of the housing member  1401  that acts as the first sub-6 GHz antenna  1402  may define structural features  1413  and  1414 . These features may extend from the interior side of the housing member  1401  and towards the interior volume of the device  1400 . The features  1413 ,  1414  may have several functions, including defining physical mounting locations for the ground and feed lines, and defining interlock features with which the material of the joining elements engage and/or encapsulate to form the structural coupling between the housing members. While the features  1413 ,  1414  are shown in  FIG.  14 A  without being encapsulated by or otherwise engaged with the material of the joining element  1416 , it will be understood that in some cases the material of the joining element  1416  contacts, engages, and/or at least partially encapsulates the features  1413  and/or the features  1414 . Further, while such features are only shown on the housing members  1401  and  1407 , the other housing members may include similar features proximate the joining elements. 
     As noted above, the second sub-6 GHz antenna  1404  and the third sub-6 GHz antenna  1406  may have the same or similar structures as the first sub-6 GHz antenna  1402 . In some cases, first, second, and third sub-6 GHz antennas are each configured to communicate via a different frequency band. Accordingly, the exact shape, length, or other physical characteristic of each of these antennas may differ from one another. 
     As noted above, the fourth sub-6 GHz antenna  1408 , which is part of the first group of antennas that operates according to a 4×4 MIMO scheme, is a conductive trace or other radiating element that is positioned within the device. In some cases, however, a portion of the first housing member  1401  that is proximate the joining element  1426  may be configured to act as the fourth sub-6 GHz antenna. In such case the first housing member  1401  may include structural features similar to those of the first sub-6 GHz antenna  1402  (e.g., the features  1413 ,  1414 ), and ground and feed lines may be similarly coupled to that region of the first housing member  1401  to facilitate transmitting and receiving electromagnetic signals. 
     While the sub-6 GHz antennas  1402 ,  1404 ,  1406 , and  1408  may be used to communicate via the sub-6 GHz spectrum, the device  1400  may also (or instead) include antennas for communicating via the millimeter-wave spectrum. The device  1400  may include, for example, a first millimeter-wave antenna  1432  and a second millimeter-wave antenna  1434 . Millimeter-wave antennas may be more directional and more susceptible to attenuation from occlusion than antennas for other spectra. For example, with respect to attenuation, if a user places his or her hand over a millimeter-wave antenna, communications via that antenna may suffer or be completely ceased. With respect to directionality, if the millimeter-wave antenna is pointed more than a certain angle away from a cell tower, the antenna may cease being able to effectively communicate with that cell tower. In order to mitigate these effects, the device may include multiple millimeter-wave antennas strategically positioned to enable wireless communications in a number of different positions, locations, orientations, or the like. For example, in the device  1400 , the first millimeter-wave antenna  1432  may be configured as a rear-fired antenna (e.g., sending and receiving electromagnetic signals primarily along a direction that is perpendicular to the rear surface of the device). The second millimeter-wave antenna  1434  may be configured as a side-fired antenna (e.g., sending and receiving electromagnetic signals primarily along a direction that is perpendicular to a side surface of the device). It will be understood that the directional millimeter-wave antennas need not be oriented directly at another antenna in order to communicate, but may tolerate slight misalignments (e.g., +/−15 degrees, +/−30 degrees, or another value). 
     Returning to  FIG.  14 A , the first (rear-fired) millimeter-wave antenna  1432  may be coupled to a logic board  1436  (which may be an embodiment of the logic boards  220 ,  320 , or any other logic board described herein). In some cases, the first millimeter-wave antenna  1432  (which may be or may include a passive antenna board) is surface mounted directly to the logic board  1436 . The first millimeter-wave antenna  1432  may include antenna arrays for two different frequencies (e.g., 28 GHz and 39 GHz, though other frequencies are also possible). Each antenna array may include four antenna elements, and each antenna element may have two different polarizations. By including two (or more, such as four) different antenna arrays, rather than using the same antenna elements for two different bands, the first millimeter-wave antenna  1432  may have a greater overall bandwidth than an antenna that uses the same antenna elements to communicate over two (or more) frequency bands. The greater bandwidth of the first millimeter-wave antenna  1432  may allow for greater tolerances in the positioning of the antenna  1432  in the device  1400  while still providing adequate antenna performance. Further, the multiple millimeter-wave antenna arrays of the first millimeter-wave antenna  1432  may be used in a diversity configuration to improve wireless communications functionality and reliability. 
     The device  1400  may also include antenna circuitry in a system-in-package (SiP) component  1438 . The SiP component  1438 , referred to herein as the SiP  1438 , may include components such as one or more processors, memory, analog-to-digital converters, filters, amplifiers, power control circuitry, or the like. The SiP  1438  may be coupled to the logic board  1436 , and may be positioned above the first millimeter-wave antenna  1432 . The antenna elements in the first millimeter-wave antenna  1432  may be conductively coupled to the SiP  1438  so that the SiP  1438  can process signals received via the first millimeter-wave antenna  1432  and cause the first millimeter-wave antenna  1432  to send signals. 
       FIG.  14 B  is a partial cross-sectional view of the device  1400 , viewed along line  14 B- 14 B in  FIG.  14 A . The cross-sectional view illustrates example details of the second (side-fired) millimeter-wave antenna  1434  of the device  1400 . The side-fired antenna  1434  (also referred to as an antenna module) is secured to an interior of the housing  1450  ( FIG.  14 A ) of the device  1400  (e.g., to the housing member  1407 ), and is configured to transmit and receive electromagnetic signals through one or more openings  1457  in the side wall of the housing member  1409 . The openings  1457  may extend through the side wall of the housing member  1409  and may at least partially define an antenna window for the side-fired antenna  1434 . 
     The side-fired antenna  1434  includes an antenna array  1466 , which includes a plurality of directional antenna elements. The antenna array  1466  may include antenna elements for two different frequencies (e.g., 28 GHz and 39 GHz, though other frequencies are also possible). For example, two antenna elements may be provided for each frequency, and each antenna element may have two different polarizations. Of course, other configurations of antenna elements are also possible. For example, the antenna array  1466  may include four antenna elements for each frequency. 
     The antenna array  1466  may include or be coupled to antenna circuitry in a SiP component. The SiP component may include components such as one or more processors, memory, analog-to-digital converters, filters, amplifiers, power control circuitry, or the like. The SiP may be conductively coupled to the logic board  1436  (e.g., via a flexible circuit element). The antenna elements in the antenna array  1466  may be conductively coupled to the SiP so that the SiP can process signals received via the antenna array  1466  and cause the antenna array  1466  to send signals. 
     The side wall of the housing member  1409  may be configured to function as a waveguide for guiding electromagnetic signals to and from the antenna array  1466 . The waveguide may be defined by a passage or hole  1459  through the side wall of the housing member  1409 . The passage  1459  may be defined in part by walls that extend from an exterior side surface of the side wall of the housing member  1409  to an interior surface of the housing member  1409 . As shown, the walls are angled such that the opening  1459  on the exterior side surface is offset from the opening on the interior surface of the housing. More particularly, the center of the opening in the exterior side surface of the side wall may be vertically offset from the center of the opening in the interior side of the housing member  1409 . 
     The vertical offset of the openings defines a generally non-horizontally aligned passage (relative to the orientation shown in  FIG.  14 B ), which allows the internal components of the side-fired antenna  1434  to be offset from a central axis of the device  1400  while also allowing the opening  1457  in the exterior side surface to be vertically centered in the exterior side surface. For example, the height  1452  of the housing member  1409  above the opening  1457  may be the same as the height  1454  of the housing member  1409  below the opening  1457 . By aligning the opening  1457  with the middle of the side surface (e.g., the middle along the vertical direction), the structural integrity (e.g., stiffness, strength, etc.) of the housing member  1409  may be higher than if the opening  1457  were offset vertically from the center of the side surface (e.g., because the amount of housing material above the opening  1457  would be different from the amount below, leading to one side being weaker than the other). Further, the central alignment of the opening  1457  provides an overall symmetrical and balanced appearance to the device  1400 . 
     The side-fired antenna  1434  may include a cover element  1462  (also referred to as an insert) within part of the passage  1459 . The insert  1462  may be a plastic, glass, or other material (e.g., a nonconductive material) insert, and may be adhered to the antenna array  1466  via an adhesive. The insert  1462  may be placed into the passage  1459 , or it may be formed in place by, for example, injecting a polymer material into the passage  1459  and allowing the polymer material to cure or otherwise harden. 
     The device  1400  may also include a cover element  1456  positioned in the passage  1459  and defining part of the exterior side surface of the device  1400  (e.g., in conjunction with the exterior side surface of the housing member  1409 ). The cover element  1456  may be formed of glass, sapphire, glass-ceramic, plastic, or any other suitable material (e.g., nonconductive material). The thickness of the cover element  1456  may be determined at least in part on the material being used and the effect of the material (and the dimensions) on the electromagnetic signals passing through the passage  1459 . For example, in order to achieve the same or similar electromagnetic performance, the thickness of the cover element  1456  may be greater if it is formed of glass than if it is formed from sapphire. If the cover element  1456  is formed of sapphire, a spacer layer (e.g., a plastic, epoxy, or other suitable material) may be included between the cover element  1456  and an adhesive (e.g., the adhesive  1460 ) that secures the cover to the device  1400 . 
     The cover element  1456  may include a mask layer  1458 , which may be applied to the back or front surface of the cover element  1456 . As shown, the mask layer  1458  is applied to the back surface of the cover element  1456 . The mask layer  1458  may be an ink, dye, film, paint, coating, or other material, and may be visible through the cover element  1456 . The mask layer  1458  may be opaque. The mask layer  1458  may also be a single layer, or it may include multiple sub-layers. The cover element  1456  may be secured to the housing member  1409  via an adhesive  1460 . The adhesive  1460  may also adhere the cover element  1456  to the insert  1462 . An outer surface of the cover element  1456  may be substantially flush with the adjacent surfaces of the housing member  1409  (e.g., the surfaces defining the heights  1452 ,  1454 ). 
     The side-fired antenna  1434  may also include a dielectric cap  1464 . The dielectric cap  1464  may be positioned on and optionally conductively coupled to the antenna array  1466 . In some cases, the dielectric cap  1464  may be considered part of the antenna array  1466 . The shape and material (e.g., the dielectric properties of the material) of the dielectric cap  1464  may contribute to the bandwidth of the side-fired antenna  1434 . For example, the bandwidth of the side-fired antenna  1434  with the dielectric cap  1464  may be greater than one without the dielectric cap  1464 . 
       FIG.  14 C  depicts a portion of the side-fired antenna  1434  separate from the device  1400 , and  FIG.  14 D  depicts a partial cross-sectional view of the portion of the side-fired antenna  1434  shown in  FIG.  14 C . As shown in  FIGS.  14 C and  14 D , the dielectric cap  1464  may include loading block features  1470 . The loading block features  1470  may be conductively coupled to antenna elements  1478  in the side-fired antenna  1434 , as shown in  FIG.  14 D . For example, vias or other conductive conduits  1472  in a circuit board  1471  or other substrate may conductively couple the loading block features  1470  to the antenna elements  1478 . The loading block features  1470  may at least partially define a radiation pattern of the respective antenna elements  1478  to which they are coupled. 
     The dielectric cap  1464  and the integral loading block features  1470  may be formed from an epoxy or other suitable moldable material. For example, the dielectric cap  1464  may be formed by molding the epoxy against the antenna array  1466 . The epoxy that is used to form the dielectric cap  1464  may have a dielectric constant between about 4 and about 6. 
     The side-fired antenna  1434  may also include a cap member  1474  at least partially enclosing the antenna elements  1478 , and a potting material  1476  in the antenna array  1466  and at least partially encapsulating the antenna elements  1478 . 
     As noted above, portions of a metal or conductive housing of a device may be used as antenna elements to send and receive wireless signals. More particularly, the portions of the metal or conductive housing may act as the radiating elements of antennas.  FIG.  14 A , for example, shows an example device  1400  that uses metal housing members to define antenna elements for the sub-6 GHz spectrum. Metal housing members may be used to define antenna elements for other frequencies and/or protocols in addition to the sub-6 GHz antennas described with respect to  FIG.  14 A .  FIG.  15    is a schematic representation of a portion of a housing  1500  formed of multiple conductive housing members joined together with joining elements.  FIG.  15    also schematically represents example connection points on the housing members where feed and/or ground lines may be conductively coupled to the housing members to carry electromagnetic signals from the housing member to other antenna circuitry (and from the antenna circuitry to the housing member). 
     As shown in  FIG.  15   , the housing  1500  may include a first housing member  1502  that defines a portion of a first side surface  1542  as well as a first corner surface  1550  and part of a second side surface  1544 . The first housing member  1502  is structurally coupled to a second housing member  1504  via a first joining element  1514 . As noted above, joining elements, such as the joining element  1514 , may be formed from a polymer material (e.g., a fiber-reinforced polymer) that can structurally join housing members while also providing sufficient electrical isolation between the housing members to allow them to act as antenna elements. 
     The housing  1500  also includes a second housing member  1504  that defines a portion of the second side surface  1544  and is structurally coupled to a third housing member  1506  via a second joining element  1516 . The third housing member  1506  defines part of the second side surface  1544  as well as a second corner surface  1552 . 
     The third housing member  1506  also defines part of a third side surface  1546  of the housing and is structurally connected to a fourth housing member  1508  via a third joining element  1518 . The fourth housing member  1508  also defines a portion of the third side surface  1546 , a third corner surface  1554 , and part of the fourth side surface  1548 . 
     The fourth housing member  1508  is coupled to a fifth housing member  1510  via a fourth joining element  1520 . The fifth housing member  1510  defines a portion of the fourth side surface  1548  and is coupled to a sixth housing member  1512  via a fifth joining element  1522 . The sixth housing member  1512  defines a portion of the fourth side surface  1548 , a fourth corner surface  1556 , and a portion of the first side surface  1542 . The sixth housing member  1512  is structurally connected to the first housing member  1502  via a sixth joining element  1525 . 
     Each of the joining elements of the housing  1500  may define a portion of an exterior surface of the housing  1500 . Thus, the exterior side surfaces of the housing  1500  may be defined entirely or substantially entirely by the housing members and the joining elements. 
     In order to operate as antenna elements, the housing members of the housing  1500  may be conductively coupled to antenna circuitry, electrical ground planes, and the like. The particular locations of the connection points on the housing members, as well as the sizes and shapes of the housing members, may at least partially define parameters of the antenna elements. Example antenna parameters may include resonant frequency, range, radiation pattern, efficiency, bandwidth, directivity, gain, or the like. 
       FIG.  15    illustrates example positions for the connection points of feed and ground lines to the housing members. For example, feed and ground lines may be conductively coupled to the first housing member  1502  at connection points  1524 - 1 ,  1524 - 2 , thereby facilitating wireless communication via the first housing member  1502 . 
     Feed and ground lines may be conductively coupled to the second housing member  1504  at connection points  1528 - 1 ,  1528 - 2  and optionally at connection points  1526 - 1 ,  1526 - 2 . The portion of the second housing member  1504  between or proximate the connection points  1526 - 1 ,  1526 - 2  may act as one antenna element, while the portion of the second housing member  1504  between or proximate the connection points  1528 - 1 ,  1528 - 2  may act as another, independent antenna element (e.g., it may send and receive electromagnetic signals independently of the antenna element between the connection points  1526 - 1 ,  1526 - 2 , despite being defined by the same housing member  1502 ). While  FIG.  15    illustrates connection points  1526 - 1 ,  1526 - 2 , these may be omitted in some implementations, such as in the device  1400  of  FIG.  14 A , which uses a conductive element on a circuit board as an antenna element in that corner of the device instead of using a housing member. 
     Feed and ground lines may be conductively coupled to the third housing member  1506  at connection points  1530 - 1 ,  1530 - 2 , and to the fourth housing member  1508  at connection points  1532 - 1 ,  1532 - 2  and connection points  1534 - 1 ,  1534 - 2 . The fourth housing member  1508  may define different antenna element configurations depending on which feed and ground lines are used at a given time. For example, in a first mode, the connection points  1532 - 1 ,  1532 - 2  are used, such that the fourth housing member  1508  is configured to communicate via a first communications protocol (or frequency), and in a second mode, the connection points  1534 - 1 ,  1534 - 2  are used, such that the fourth housing member  1508  is configured to communicate via a second communications protocol (of frequency) that differs from the first. 
     Feed and ground lines may be conductively coupled to the fifth housing member  1510  at connection points  1536 - 1 ,  1536 - 2 , and at connection points  1538 - 1 ,  1538 - 2 . Similar to the configuration of the second housing member  1504 , the portion of the fifth housing member  1510  between or proximate the connection points  1536 - 1 ,  1536 - 2  may act as one antenna element, while the portion of the fifth housing member  1510  between or proximate the connection points  1538 - 1 ,  1538 - 2  may act as another, independent antenna element (e.g., it may send and receive electromagnetic signals independently of the antenna element between the connection points  1536 - 1 ,  1536 - 2 , despite being defined by the same housing member  1510 ). Feed and ground lines may also be conductively coupled to the sixth housing member  1512  at connection points  1540 - 1 ,  1540 - 2 . 
     As noted above, the housing members of the herein described device housings may be used to form multiple groups or sets of antennas, with each group or set communicating via a different communication protocol or frequency band. For example, the housing may define multiple antennas of a first MIMO antenna array or group (e.g., for a 4G communication protocol) as well as multiple antennas of a second MIMO antenna array (e.g., for a 5G communication protocol). In one non-limiting example configuration, the antenna elements defined by the connection points  1524 ,  1530 ,  1532 ,  1534 , and  1540  may be configured to operate as part of a first MIMO antenna array (e.g., for a 4G communication protocol), while the antenna elements defined by the connection points  1526  (if provided),  1528 ,  1536 , and  1538  may be configured to operate as part of a second MIMO antenna array (e.g., for a 5G communication protocol). For any given antenna group, the antenna elements of that group do not all need to be housing members. For example, the second MIMO antenna array or group may use an internal antenna (e.g., the antenna  1408 ,  FIG.  14 A ) as one of the antennas in a 4×4 MIMO array. 
     As described above, conductive housing members, which may act as a radiating structure of an antenna or antenna system, may be structurally coupled together via joining elements. The joining elements may be formed from a polymer material or other dielectric material that can provide sufficient electrical isolation between housing members to facilitate the use of the housing members as radiating structures for antennas. In some cases, the joining elements include one, two, or more molded elements, which are molded into a gap between the housing members and into engagement with the housing members. Because the joining elements structurally retain housing members together, a strong engagement between the joining elements and the housing members may be preferred. Accordingly, the housing members may include or define structures and/or features that a joining element engages in order to retain the joining element to the housing members, and thereby retain the housing members together. 
       FIG.  16 A  illustrates an example housing member  1600  that includes features with which a joining element may engage. The portion of the housing member shown in  FIG.  16 A  may correspond generally to the area  16 A- 16 A in  FIG.  14 A . 
     The housing member  1600  may be formed from or include a conductive material, such as stainless steel, aluminum, a metal alloy or the like, and may be conductively coupled to an antenna circuit (e.g., via feed and/or ground lines, as described above) to act as a radiating structure for a device. The portion of the housing member  1600  shown in  FIG.  16 A  may abut and/or engage with a joining element, as shown in  FIG.  16 B . 
     The housing member  1600  defines a first interlock feature  1602  that extends inwardly (e.g., towards an interior of the device) from a sidewall  1601  defined by the housing member  1600 . The first interlock feature  1602  may extend from an interior side  1605  of the housing member  1600 , where the interior side  1605  is opposite an exterior side  1603 . 
     The sidewall  1601  may define an exterior surface of the device of which the housing member  1600  is a part. The first interlock feature  1602  may define a first hole  1604  and one or more second holes  1606 . When a joining element is formed by injecting or otherwise molding a moldable material against the housing member  1600 , the moldable material may at least partially surround and/or encapsulate the first interlock feature  1602 , and may flow into and optionally through the first and second holes  1604 ,  1606 . By at least partially encapsulating the interlock feature  1602  and flowing into and/or through the first and second holes  1604 ,  1606 , the joining elements may be structurally interlocked with the housing member  1600 , thereby securely retaining the joining element to the housing member  1600 . 
     The housing member  1600  may also define a second interlock feature, such as a recess  1610 , which may be an indentation, cavity, or other similar feature that is recessed relative to an end surface  1608  of the housing member  1600 . The end surface  1608  of the housing member  1600  may be the portion of the housing member  1600  that extends closest to another housing member to which the housing member  1600  is coupled via a joining element. The end surface  1608  may be offset from an end surface  1609  defined by the first interlock feature  1602 . More particularly, the end surface  1609  may be recessed relative to the end surface  1608  (e.g., along a direction that is perpendicular to the end surfaces  1608 ,  1609 ). 
     The recess  1610  may have a depth between about 100 microns and about 1000 microns, and may have a width (e.g., the left-to-right dimension as depicted in  FIG.  16 A ) between about 100 microns and about 400 microns, and a length (e.g., the top-to-bottom dimension as depicted in  FIG.  16 A ) between about 750 microns and about 3000 microns. In some cases, the housing member  1600  may also define pores along the end surface  1608  and/or the end surface  1609 . The pores may be formed on the end surfaces  1608  and/or  1609 , and may also be formed on the surface of the recess  1610 . The pores may be a distinct structure than the recess  1610 . For example, the recess  1610  may have a length dimension greater than about 1000 microns and a width dimension greater than about 100 microns, while the pores may have length and/or width dimensions less than about 10 microns. Similarly, the recess  1610  may have a depth greater than about 100 microns, while the pores may have a depth less than about 10 microns. In some cases, the pores are formed by chemical etching, abrasive blasting, laser or plasma etching, or the like. The material of the joining element may extend or flow into the pores during formation of the joining element and engage and/or interlock with the pores to secure the joining element to the housing member  1600 . In some cases, the pores are formed after the recess  1610  is formed, such that the pores are present on the surface of the recess  1610 . In other cases, the pores are formed prior to formation of the recess  1610 , such that the surface of the recess  1610  lacks the pores, or has a different surface morphology and/or topography than the end surface on which the pores are formed (e.g., the end surface  1608  may have pores from a chemical etching, while the recess  1610  may have machine marks from a machining process). In some cases, the largest dimension (e.g., length, width, depth) of the pores is at least an order of magnitude smaller than the largest dimension (e.g., length, width, depth) of the recess  1610 . 
     The housing member  1600  may define a flange portion  1607  that is adjacent to and/or extends along a peripheral side of a top module (which may include a cover member, a display, touch-sensing components, and the like). In some cases, the second interlock feature  1610  (e.g., the recess, as shown) is positioned in the flange portion  1607 , thereby reinforcing the portion of the joint that is along the side of the top module. More particularly, the flange portion  1607  may define a cantilever that extends away from the first interlock feature  1602 , and the second interlock feature  1610  may provide a supplemental interlocking engagement with a joining element to help prevent or limit separation or detachment of the flange portion  1607  from the joining element (e.g., the joining element  1612 ,  FIG.  16 B ). The flange may extend along a direction (e.g., the vertical direction in  FIG.  16 A , which may be parallel to an exterior side surface defined by the housing member  1600  and/or perpendicular to the front surface defined by a cover member of the device), and the second interlock feature  1610  may be an elongate recess or channel with a longitudinal axis that extends parallel to the exterior side surface of the housing member (e.g., along the same direction that the flange extends from the first interlock feature  1602 ). 
     When a moldable material is flowed into place (e.g., between the housing member  1600  and another housing member) to form a joining element, the moldable material may flow into and at least partially fill the recess  1610 , thereby forming a corresponding protrusion in the moldable material. When the moldable material is then cured or otherwise hardened, the protrusion of the joining element and the recess  1610  interlock with one another. The interlock between the recess  1610  and the protrusion may help prevent separation of the joining element and the housing member  1600 . Further, the position of the recess  1610  relative to the exterior surface defined by the sidewall  1601  may help improve the structural rigidity of the joint and help maintain the alignment (and mechanical coupling) between the housing member  1600 , the joining element, and the adjoining housing member in the event of a drop or other impact event. For example, while the first interlock feature  1602  may provide substantial structural strength to the interface between the joining element and the housing member  1600 , its position is further inboard (e.g., relatively nearer the internal volume of a housing) than the recess  1610 . By contrast, the further outboard position of the recess  1610  (e.g., relatively nearer the external surface of the housing member  1600 ) may improve the strength and stability of the alignment between the exterior surfaces of the housing members and the joining element. 
       FIG.  16 B  is a partial cross-sectional view of the housing member  1600  (joined to another housing member  1616  via a joining element  1612 ), viewed along line  16 B- 16 B in  FIG.  16 A . (While  FIG.  16 A  does not show the joining element and the housing member  1616 ,  FIG.  16 B  represents the view along line  16 B- 16 B if such components were present.) The joining element  1612  may be positioned between and in contact with the end surface  1608  of the housing member  1600  and a corresponding end surface  1617  of the housing member  1616 . The joining element  1612  may also extend into and interlock with the recess  1610  of the housing member  1600 , as well as a recess  1614  defined by the housing member  1616 . In addition to the mechanical interlocking between the joining element  1612  and the recesses  1610 ,  1614  (and/or other retention structures and/or interlock features), the moldable material of the joining element  1612  may form a chemical or other adhesive bond with the material of the housing members  1600 ,  1616 . 
     The exterior surfaces of the joining element  1612  and the housing members  1600 ,  1616  may define a smooth continuous exterior surface  1613  of the housing. For example, any gaps, seams, or other discontinuities between the joining element  1612  and the housing members  1600 ,  1616  along the exterior surface  1613  of the housing may be undetectable to the touch and/or to the unaided eye. For example, a fingernail sliding along the exterior surface  1613  may not catch on the seam between the joining element  1612  and the housing members  1600 ,  1616 . In some cases, any gap, seam, or other discontinuity between the joining element  1612  and the housing members  1600 ,  1616  may be less than about 200 microns, less than about 100 microns, less than about 50 microns, less than about 20 microns, or less than about 10 microns (in depth, length, offset, and/or other dimension). The interlock between the joining element  1612  and the recesses  1610 ,  1614  may help prevent or inhibit relative motion between the housing members  1600 ,  1616  and the joining element  1612 , such as relative motion of these components along a vertical direction (as oriented in  FIG.  16 B ). Accordingly, the recesses  1610 ,  1614  may help maintain the substantially seamless texture and appearance between the joining element  1612  and the housing members  1600 ,  1616 . 
       FIG.  16 C  illustrates another example housing member  1620  that includes features with which a joining element may engage. The housing member  1620  may be formed from or include a conductive material, such as stainless steel, aluminum, a metal alloy or the like, and may be conductively coupled to an antenna circuit (e.g., via feed and/or ground lines, as described above) to act as a radiating structure for a device. The portion of the housing member  1620  shown in  FIG.  16 C  may abut and/or engage with a joining element, as shown in  FIG.  16 D . 
     The housing member  1620  defines a first interlock feature  1622  that extends inwardly (e.g., towards an interior of the device) from a sidewall  1621  defined by the housing member  1620 . The first interlock feature  1622  may extend from an interior side of the housing member  1620  (e.g., analogous to the interior side  1605 ,  FIG.  16 A ), where the interior side is opposite an exterior side (e.g., analogous to the exterior side  1603 ,  FIG.  16 A ). 
     The sidewall  1621  may define an exterior surface of the device of which the housing member  1620  is a part. The first interlock feature  1622  may define a first hole  1624  and one or more second holes  1626 . When a joining element is formed by injecting or otherwise molding a moldable material against the housing member  1620 , the moldable material may at least partially surround and/or encapsulate the first interlock feature  1622 , and may flow into and optionally through the first and second holes  1624 ,  1626 . By at least partially encapsulating the interlock feature  1622  and flowing into and/or through the first and second holes  1624 ,  1626 , the joining elements may be structurally interlocked with the housing member  1620 , thereby securely retaining the joining element to the housing member  1620 . 
     The housing member  1620  may also define a protruding feature  1630 , which may be a post, pin, or have any other suitable shape or configuration that protrudes or extends from an end surface  1628  of the housing member  1620 . The end surface  1628  of the housing member  1620  may be the portion of the housing member  1620  that, with the exception of the protruding feature  1630 , extends closest to another housing member to which the housing member  1620  is coupled via a joining element. 
     The protruding feature  1630  may operate in a similar manner as the recess  1610  in  FIGS.  16 A- 16 B . For example, when a moldable material is flowed into place (e.g., between the housing member  1620  and another housing member) to form a joining element, the moldable material may flow around the protruding feature  1630  to at least partially encapsulate the protruding feature  1630 . When the moldable material is then cured or otherwise hardened, the protruding feature  1630  and the recess in the moldable material that is formed around the protruding feature  1630  interlock with one another. The interlock between the protruding feature  1630  and the moldable material may help prevent separation of the joining element and the housing member  1620 . Further, the position of the protruding feature  1630  relative to the exterior surface defined by the sidewall  1621  may help improve the structural rigidity of the joint and help maintain the alignment (and mechanical coupling) between the housing member  1620 , the joining element, and the adjoining housing member in the event of a drop or other impact event. For example, while the first interlock feature  1622  may provide substantial structural strength to the interface between the joining element and the housing member  1620 , its position is further inboard (e.g., relatively nearer the internal volume of a housing) than the protruding feature  1630 . By contrast, the further outboard position of the protruding feature  1630  (e.g., relatively nearer the external surface of the housing member  1620 ) may improve the strength and stability of the alignment between the exterior surfaces of the housing members and the joining element. 
     In some cases, the housing member  1620  may also define pores along the end surface  1628  and/or the end surface  1629 . The pores may be formed on the end surfaces  1628  and/or  1629 , and may also be formed on the surface of the protruding feature  1630 . The pores may be a distinct structure than the protruding feature  1630 . For example, the protruding feature  1630  protrudes by a distance greater than about 100 microns, and may have a length and width dimension greater than about 100 microns, while the pores may have depth, length, and/or width dimensions less than about 10 microns. In some cases, the pores are formed by chemical etching, abrasive blasting, laser or plasma etching, or the like. The material of the joining element may extend or flow into the pores during formation of the joining element and engage and/or interlock with the pores to secure the joining element to the housing member  1620 . In some cases, the pores are formed after the protruding feature  1630  is formed, such that the pores are present on the surfaces of the protruding feature  1630 . In other cases, the surfaces of the protruding feature  1630  lack the pores, or have a different surface morphology and/or topography than the end surface on which the pores are formed. In some cases, the largest dimension (e.g., length, width, depth) of the pores is at least an order of magnitude smaller than the largest dimension (e.g., length, width, depth) of the protruding feature  1630 . 
       FIG.  16 D  is a partial cross-sectional view of the housing member  1620  (joined to another housing member  1625  via a joining element  1632 ), viewed along line  16 D- 16 D in  FIG.  16 C . (While  FIG.  16 C  does not show the joining element  1632  and the housing member  1625 ,  FIG.  16 D  represents the view along line  16 D- 16 D if such components were present.) The joining element  1632  may be positioned between and in contact with the housing members  1620 ,  1625 . The joining element  1632  may also at least partially (and optionally fully) encapsulate the protruding feature  1630 . As can be seen in  FIG.  16 D , the protruding feature  1630  may extend and/or be adjacent to two offset surfaces. For example, with respect to the housing member  1620 , the two offset surfaces include the end surface  1628  and an additional end surface  1629 . The protruding feature  1630  may extend a first distance from the end surface  1628 , and a second (greater) distance from the additional end surface  1629 . A similar structure may be used on the housing member  1625  (e.g., a protruding feature  1636  extending a first distance from an end surface  1638  and a second (greater) distance from an additional end surface  1634 ). Thus, as shown in  FIG.  16 D , the end surfaces  1628 ,  1638  may be closer together than the additional end surfaces  1629 ,  1634  (and the ends of the protruding features  1630 ,  1636  may be the portions of the housing members  1620 ,  1625  that are closest together). In addition to the mechanical interlocking between the joining element  1632  and the protruding features  1630 ,  1636  (and any other retention structures and/or interlock features), the moldable material of the joining element  1632  may form a chemical or other adhesive bond with the material of the housing members  1620 ,  1625 . 
     The exterior surfaces of the joining element  1632  and the housing members  1620 ,  1625  may define a smooth continuous exterior surface  1623  of the housing. For example, any gaps, seams, or other discontinuities between the joining element  1632  and the housing members  1620 ,  1625  along the exterior surface  1623  of the housing may be undetectable to the touch and/or to the unaided eye. For example, a fingernail sliding along the exterior surface  1623  may not catch on the seam between the joining element  1632  and the housing members  1620 ,  1625 . In some cases, any gap, seam, or other discontinuity between the joining element  1632  and the housing members  1620 ,  1625  may be less than about 200 microns, less than about 100 microns, less than about 50 microns, less than about 20 microns, or less than about 10 microns (in depth, length, offset, and/or other dimension). The interlock between the joining element  1632  and the housing members  1620 ,  1625  may help prevent or inhibit relative motion between the housing members  1620 ,  1625  and the joining element  1632 , such as relative motion of these components along a vertical direction (as oriented in  FIG.  16 D ). Accordingly, the protruding features  1630 ,  1636  may help maintain the substantially seamless texture and appearance between the joining element  1632  and the housing members  1620 ,  1625 . 
     In some cases, different types of structures may be used to reinforce or otherwise increase the strength and/or structural integrity of the coupling between housing members and joining elements.  FIG.  16 E , for example, illustrates an example cross-sectional view of a housing that includes a joining element  1643  and a first housing member  1640  that defines a protruding feature  1644  (as shown in  FIGS.  16 C- 16 D ) and a second housing member  1641  that defines a recess  1649  (as shown in  FIGS.  16 A- 16 B ). Using a protruding feature  1644  and a recess  1649  may help increase the average or overall distance between the nearest portions of the first and second housing members  1640 ,  1641 . In particular, because one or both of the housing members  1640 ,  1641  may be used as a radiating component of an antenna system, it may be desirable to increase the distance between them to reduce capacitive coupling or other electromagnetic effects due to proximity of the two conductive components. By positioning a recess opposite a protrusion, the structural benefits of the protrusion (and the recess) may be achieved while also providing a greater distance between the closest surfaces of the housing members  1640 ,  1641  (as compared to a configuration with two protruding features, for example). 
       FIG.  17 A  illustrates an example arrangement of cameras in a rear-facing sensor array of a device  1700 .  FIG.  17 A  may correspond to a corner of a device (e.g., the devices  100 ,  200 ), viewed with the cover and display (and optionally other components) removed to show the arrangement of the cameras. The device  1700  may include a first camera module  1702  (which may be an embodiment of or otherwise correspond to the first camera  138  in  FIG.  1 B , and/or the first camera  261  in  FIG.  2   ) and a second camera module  1704  (which may be an embodiment of or otherwise correspond to the second camera  139  in  FIG.  1 B , and/or the second camera  262  in  FIG.  2   ). The first and second camera modules  1702  and  1704  may include camera housings. Any of the cameras shown in  FIG.  17 A  (or elsewhere herein) may include an image stabilization system that helps maintain a sharp image (e.g., reducing the effects of camera shake on the image) by sensing movement of the device and moving one or more components of the camera in a manner that at least partially compensates for (and/or counteracts) the movement of the device. 
     The device  1700  may also include a bracket member  1706  (also referred to herein as a camera bracket) to which the first and second camera modules  1702 ,  1704  may be coupled. The bracket member (or camera bracket)  1706  may define first and second respective camera portions  1780 ,  1781 , or receptacles, to which the first and second respective camera modules may be coupled. The first and second camera portions  1780 ,  1781  may be positioned along the diagonal path defined from the first corner region to the second corner region of the rear-facing sensor array. Each camera portion may define an opening for the optical components (e.g., lenses) of its respective camera module. The camera portions (e.g., receptacles) may be defined by flanges or side walls that at least partially surround the camera modules. The bracket member  1706  may be configured to fix the relative positions of the camera modules. 
     In modern consumer electronic devices, such as mobile phones, internal space is at a premium, and space-saving arrangements of components can have a significant positive impact on various aspects of the device. For example, space-saving or compact arrangements of components can free up internal space that can be used to increase the size and capacity of a battery, or can be used to make the device smaller, thinner, and/or lighter.  FIG.  17 A  shows one example configuration of the camera modules that reduces the overall footprint of the camera modules in the system. In particular, the first camera module  1702  (e.g., the camera housing of the first camera module) defines a recess  1708  at a corner of the module. For example, instead of a convex corner, one of the corners of the first camera module  1702  is a concave shape (e.g., a recess  1708 ). This configuration allows a corner of the second camera module  1704  (e.g., a corner of a housing of the second camera module) to extend into the recess  1708 , thereby allowing the first and second camera modules  1702 ,  1704  to be positioned more closely together than would be possible if the first camera module  1702  had conventional convex corners. 
     In some cases the first camera module  1702  may have a generally quadrilateral shape with three convex corners and one concave corner. In some cases, the first camera module  1702  has a parallelogram shape with three convex corners and one concave corner. 
       FIG.  17 A  shows the first camera module  1702  defining the concave corner and a portion of the second camera module  1704  (e.g., a convex corner of the second camera module  1704 ) positioned in the concave corner of the first camera module  1702 . In other implementations, the second camera module  1704  may define a concave corner, and a convex corner of the first camera module  1702  may be positioned in the concave corner of the first camera module. In some cases, portions of other components or structures of an electronic device are positioned in the concave corner of a camera module, such as a fastener, a mounting post, a battery, a housing member, a circuit board, or the like. The device  1700  may also include a frame member  1710  to which the bracket member  1706  may be attached. The frame member  1710  may define a wall structure  1731  ( FIG.  17 D ), which in turn defines a container region  1723  ( FIG.  17 D ). As described herein, one or more cameras (which may be mounted to the bracket member  1706 ) may be positioned in the container region  1723 . 
       FIG.  17 B  depicts the first and second camera modules  1702 ,  1704  and the bracket member  1706  removed from the device  1700 . The bracket member  1706  may be a structural component that defines the positions of the first and second camera modules  1702 ,  1704  relative to each other. The bracket member  1706  may serve as a rigid structure to prevent or inhibit the first and second camera modules  1702 ,  1704  from moving, twisting, or shifting relative to one another during use or misuse of the device  1700 . The bracket member  1706  may therefore have a structural configuration that contributes to the rigidity, stiffness, and/or strength of the bracket member  1706 . For example, the bracket member  1706  may define, along one side of the first camera portion  1780  and along one side of the second camera portion  1781 , a web portion  1716  (or web  1716 ) and an outer wall  1714 , also referred to as a stiffening wall. As shown in  FIG.  17 C , the web  1716  resembles a plate having a thickness, and the stiffening wall  1714  extends from the web  1716  along at least one side of the web  1716 . Accordingly, the stiffening wall  1714  defines a T-shaped flange extending from opposite sides of the web  1716 . This configuration increases the area moment of inertia of the bracket member  1706 , thereby increasing its resistance to twisting, bending, flexing, or other deflections or deformations. The web  1716  may also define holes  1713 , through which mounting posts and/or fasteners may extend to secure components (including optionally the bracket member  1706  itself) to the frame member  1710  and/or the device more generally. 
     The web  1716  and stiffening wall  1714  may define a recessed area of the bracket member  1706 . In some cases, one or more device components may be positioned in the recessed area defined by these features. For example, a flexible circuit element  1711  ( FIG.  17 A ) that conductively couples the first camera module  1702  to another component (e.g., a logic board, processor, etc.) may be positioned in the recessed area. In such cases, the recessed area, and more particularly the stiffening wall  1714 , may protect the flexible circuit element  1711 . 
       FIG.  17 C  depicts an opposite side of the bracket member  1706  and the first and second camera modules  1702 ,  1704 . As shown, a first lens  1718  of the first camera module  1702  and a second lens  1720  of the second camera module  1704  may extend through the bracket member  1706  and beyond a bottom surface  1721  of the bracket member  1706 . The lenses  1718 ,  1720  may extend into corresponding openings in the frame member  1710  and may be positioned adjacent camera covers of the device  1700  (e.g., camera covers  263 ,  264 ,  FIG.  2   ). The first lens  1718  may have a first field of view, and the second lens  1720  may have a second field of view that is different from the first field of view. 
       FIG.  17 D  depicts the frame member  1710  secured to the housing of the device  1700 , with the bracket member  1706  and the first and second camera modules  1702 ,  1704  removed. The frame member  1710  may define openings  1724  and  1728  into which lenses of the first and second camera modules  1702 ,  1704  may extend. The openings  1724 ,  1728  may be aligned with camera covers, such as the covers  263 ,  264  in  FIG.  2   . The frame member  1710  may define mounting posts  1729 . The mounting posts  1729  may extend through openings in the bracket member  1706 , and may receive fasteners that secure one or more components to the frame member  1710  (e.g., a cowling or cover that extends over the camera modules, the bracket member  1706 , etc.). 
     The frame member  1710  also defines a wall structure  1731  extending around all or at least a portion of an outer periphery of the frame member  1710  (and extending at least partially around a periphery of the bracket member  1706  when the bracket member  1706  is positioned in the container region  1723 ). Biasing springs  1730 ,  1732  may be coupled to the wall structure  1731  to provide biasing forces on the bracket member  1706  and to help maintain the bracket member  1706  (and thus the first and second camera modules  1702 ,  1704 ) in a target position. For example, the first biasing spring  1730  may impart a biasing force on the bracket member  1706  tending to push the bracket member  1706  in a positive y direction (e.g., towards a top of the device), while the second biasing spring  1732  may impart a biasing force tending to push the bracket member  1706  in a positive x direction (e.g., towards a lateral side of the device). These biasing forces may ultimately force the bracket member  1706  against the wall structure  1731  and help maintain the bracket member  1706  in that position during use (or misuse) of the device. Further, the biasing springs  1730 ,  1732  may provide compliance to the bracket member  1706 , such that impacts or other forces acting on the device may cause the bracket member  1706  to be forced against the biasing springs  1730 ,  1732 . Because the biasing springs  1730 ,  1732  are flexible and/or compliant, they can absorb some of the energy and allow the bracket member  1706  to move slightly, rather than the bracket member  1706  itself absorbing all of the impact and/or energy, which could damage the camera modules, cause misalignment of the camera modules and/or the bracket member  1706 , or the like. 
       FIGS.  17 E and  17 F  depict a detail view of the frame member  1710  and biasing spring  1730 , corresponding to area  17 E- 17 E in  FIG.  17 D . The biasing spring  1730  may include a beam member that defines an attachment region  1735  where the beam is attached to the wall structure  1731  (e.g., via welding, adhesive, fasteners, rivets, heat stakes, brazing, soldering, etc.). The beam may also define compliant portions  1734 , which may be curved, extending from the attachment region  1735 , and contact regions  1736  extending from the compliant portions  1734 . The contact regions  1736  may contact the bracket member  1706  and may impart the biasing force produced by the biasing spring  1730  onto the bracket member  1706 . 
     The compliant portions  1734  may deflect and/or deform (e.g., towards the wall structure  1731 ) when the bracket member  1706  is positioned in the frame member  1710 . The compliant portions  1734  may have a curvature that is generally convex towards the wall structure  1731 . The convex curvature of the compliant portions  1734  may provide a dynamic fulcrum location along the compliant portions  1734 . For example, as shown in  FIG.  17 E , when the bracket member  1706  is not yet installed, the fulcrum location  1737  of the compliant portions  1734  (e.g., where the compliant portions  1734  contact and/or bend against the wall structure  1731 ) are proximate the attachment region  1735 . As shown in  FIG.  17 F , when the bracket member is installed, the fulcrum location  1739  is further towards the distal ends (e.g., towards the contact regions  1736 ) of the biasing spring  1730 . If the bracket member  1706  were to be forced towards the wall structure  1731  (e.g., due to the device being dropped onto a hard surface, for example), the compliant portions  1734  may deflect further towards the wall structure  1731 , resulting in the fulcrum locations moving even further outboard towards the distal ends of the biasing spring  1730 . The dynamic fulcrum locations may also correspond to differing or varying spring rates of the biasing spring  1730 . For example, as the fulcrum location moves outboard, the spring rate of the biasing spring may increase or otherwise change in accordance with the deflection, resulting in a greater resistance to further deformation or deflection. In some cases, the spring rate may remain substantially constant despite movement of the fulcrum location. In some cases, the spring rate may vary in a nonlinear way as the fulcrum location moves outboard. The particular spring rate and/or spring rate changes (e.g., caused by the dynamic fulcrum location) may be selected to produce a desired force or movement profile of the bracket member  1706 . 
     While  FIGS.  17 D- 17 F  show the biasing springs as each having two compliant portions, other examples may have only a single compliant portion (e.g., the biasing springs may have one “wing” instead of two “wings” as shown). Further, while  FIGS.  17 E- 17 F  describe the biasing spring  1730 , the discussion applies equally to the biasing spring  1732 . The biasing springs  1730 ,  1732  may be formed from any suitable material, such as metal (e.g. aluminum, steel, titanium), a polymer, a fiber-reinforced polymer (e.g., carbon fiber), and/or a composite material. The biasing springs  1730 ,  1732  may be a single, monolithic member (e.g., a unitary piece of metal), or they may be formed from multiple components. 
       FIG.  17 G  depicts an example arrangement of several components within the device  1700 , including several shrouds that are positioned over components of the device  1700 . For example, a camera shroud  1748  may be positioned over the first and second camera modules  1702 ,  1704  of the device  1700 . In examples where a device includes more or fewer cameras, the same or a similar camera shroud  1748  may be used.  FIG.  17 G  also depicts a logic board shroud  1749  positioned over at least a portion of a main logic board  1750 .  FIG.  17 G  also depicts a speaker module  1760 , which may be an embodiment of the speaker modules  250 ,  350 , or any other speaker modules described herein. The speaker module  1760  may include a shroud that at least partially covers the speaker module  1760 . 
     The shrouds may be formed from metal, plastic, carbon fiber, or any other material(s). The shrouds may be configured to protect underlying components from physical damage due to contact with other components (e.g., a top module), as well as to provide electromagnetic shielding between components. The shrouds may be affixed to the device in various ways. In some cases, for example, the shrouds may be affixed to the device via fasteners such as screws or bolts. 
       FIG.  17 H  depicts a partial cross-sectional view of the device  1700 , viewed along line  17 H- 17 H in  FIG.  17 G , illustrating an example configuration of the camera shroud  1748 . As noted above, shrouds may act as a physical barrier between components of the device. The camera shroud  1748 , for example, acts as a barrier between the camera module(s) and the top module, and can help prevent the camera(s) and the top module from contacting and potentially damaging each other during drops, impacts, or other forceful events. Some shrouds may be designed with physical compliance or flexibility to help dissipate or reduce the energy from an impact.  FIG.  17 H  illustrates an example configuration for securing the camera shroud  1748  to the device while also providing physical compliance to the camera shroud  1748 . The camera shroud  1748  may have a wrapped segment such that the camera shroud  1748  has two levels. More particularly, the camera shroud  1748  may define a top portion  1775 , a loop portion  1763 , and a lower portion  1774 . The top portion  1775  may define a clearance hole  1762  to provide access for a fastener  1766  (e.g., a screw, bolt, etc.) to pass through to reach a fastening hole  1765  defined through the lower portion  1774 . The fastener  1766  may capture a portion of the lower portion  1774  between a flange of the fastener  1766  and a top surface of a mounting post  1767  to secure the camera shroud  1748  to the device. The mounting post  1767  may be attached to a base  1764 , which may be a frame, base, plate, or other structure of the device. 
     The multi-level configuration of the camera shroud  1748 , and more particularly the loop portion  1763 , may provide physical compliance to the camera shroud  1748 . For example, the loop portion  1763  may act as a spring or other compliant structure that bends when a force is applied to the top portion  1775  (e.g., by a component of the top module), thus allowing the top portion  1775  to move relative to the lower portion  1774 . The bending or flexing of the loop portion  1763  may absorb and/or dissipate energy associated with the impact, or otherwise reduce the magnitude of shock loading or other forces resulting from contact with the camera shroud  1748 . 
     Parameters of the loop portion  1763 , such as spring constant, stiffness, or the like, may be defined by the materials and/or dimensions of the loop portion  1763 . For example, the thickness of the loop portion may be selective to provide a particular spring constant to the camera shroud  1748 . The thickness of the loop portion  1763  may be constant, or it may vary along the length of the loop portion  1763 . The thickness of the loop portion  1763  may be the same as or different from the thickness of the top and lower portions  1775 ,  1774 . 
       FIG.  17 I  depicts a partial cross-sectional view of the device  1700 , viewed along line  17 I- 17 I in  FIG.  17 G , illustrating an example configuration for mounting the logic board shroud  1749  and the speaker module  1760  ( FIG.  17 G ) to a device. As shown in  FIG.  17 I , both the logic board shroud  1749  (or a mounting tab of the logic board itself, such as the tab portion  2108 ,  FIG.  21 B ) and a mounting tab  1776  of the speaker module  1760  may be secured to the device via a single fastening assembly. In particular, the mounting tab  1776  may be captured between a mounting post  1772  and a main fastener  1769 . 
     A compliant member  1773  may be attached to the mounting tab  1776 . The compliant member  1773  may be formed of a polymer such as silicone, rubber, or the like, and may be compressed or otherwise captured between the mounting post  1772  and the main fastener  1769 , thereby imparting a corresponding compression force on the mounting tab  1776  to secure and substantially immobilize the speaker module  1760 . The compliant member  1773  may help inhibit the transmission of vibrations, oscillations, or other physical forces from the speaker module  1760  to other components of the device  1700  through the mounting post  1772 . More particularly, the speaker module  1760  is configured to output sounds, such as music, notification sounds (e.g., ringtones), voice output for telephone calls, audio tracks for videos or movies, and the like. As such, the speaker module  1760  (and more particularly a diaphragm of the speaker module  1760 ) vibrates in order to produce the sounds. These vibrations may be detrimental to other components of the device. For example, vibrations may cause other components such as fasteners, electrical connectors, or the like, to loosen and potentially become detached. Vibrations may also contribute to the weakening of adhesive joints or cause unwanted rubbing or friction between components in a device. Accordingly, the compliant member  1773  may help reduce the effect (e.g., amount, amplitude, frequency, etc.) of vibrations from the speaker module  1760  on the mounting post  1772  and/or main fastener  1769 , and thus reduce the transfer of vibrations to other components of the device  1700  (e.g., to the logic board via a tab portion  2108  or other mounting tab of the logic board). The particular properties of the compliant member, such as the durometer, vibration damping characteristics, and the like, may be selected based on the parameters of the expected vibrations from the speaker module  1760  (e.g., the amplitude and/or frequency of the expected vibrations). 
     As shown in  FIG.  17 I , both the speaker module  1760  and the logic board shroud  1749  may be secured to the device using a single fastening assembly. The main fastener  1769  may define a threaded post portion  1771  that threads into the mounting post  1772 , as well as a threaded hole portion  1770  into which a threaded fastener  1768  (e.g., a screw, bolt, etc.) threads. The logic board shroud  1749  may be captured between the fastener  1768  and the main fastener  1769 . As described above, the compliant member  1773  may help inhibit vibrations from the speaker module  1760  from being transferred to the logic board shroud  1749 . 
     Returning to  FIG.  17 A , the device  1700  may include a barrier wall  1740  (or wall  1740 ) that is positioned between the battery  1741  of the device  1700  and the cameras (including the first and second camera modules  1702 ,  1704 . The wall  1740  may be configured to prevent or inhibit any potential motion of the battery  1741  from damaging the cameras and/or the flexible circuit elements that connect the cameras to other circuitry of the device. The wall  1740  may be formed of metal, polymer, carbon fiber, or the like, and may be attached to a housing member or other component of the device  1700  (e.g., via adhesive, welding, fasteners, etc.). In some cases, portions of flexible circuit elements  1711  and  1745  are routed between the wall  1740  and the cameras. These portions of the flexible circuit elements  1711  and  1745  may be coupled to a joint connector  1746 , which may physically and electrically couple to a corresponding connector on another component of the device  1700 , such as a main logic board or the like. The joint connector may thereby conductively couple both the first and second camera modules  1702 ,  1704  to other circuitry of the device  1700 . 
     In order for portions of the flexible circuit elements  1711  and  1745  to fit between the cameras and the wall  1740 , those portions of the flexible circuit elements  1711  and  1745  may be oriented substantially vertically, while other portions of the flexible circuit elements  1711  and  1745  may be oriented substantially horizontally. In such cases, the portions of the flexible circuit elements  1711  and  1745  that are between the wall  1740  and the cameras may be substantially perpendicular to other portions of the flexible circuit elements  1711  and  1745  (e.g., the portion of the flexible circuit element  1711  that extends between the first camera module  1702  and the wall  1740 , and the portion of the flexible circuit element  1745  that extends from the second camera module  1704  to the vertical portion of the flexible circuit element  1745  (e.g., the portion between the wall  1740  and the second camera module  1704  itself). 
     The wall  1740  may define one or more recesses or jogged regions to accommodate portions of the battery  1741 . For example, the battery  1741  may include a flexible pouch that contains the battery cell therein. The flexible pouch may be formed by fusing or attaching two layers of a flexible material together around a periphery of the battery cell. The layers that are attached may be folded up against the side of the battery such that the sides or edges of the battery are irregular or otherwise not perfectly straight. For example, as shown in  FIG.  17 A , the battery  1741  defines a protruding portion  1742  at a corner of the battery  1741 . The protruding portion  1742  may correspond to or be a result of folding a portion of the pouch against a side of the battery. In other cases, the protruding portion  1742  is an outwardly protruding portion that corresponds to an internal recess in the pouch that accommodates circuitry, additional battery cells, or the like. Regardless of the function of a protruding portion  1742 , the wall  1740  may define one or more recesses into which the protruding portion  1742  extends. For example, the first segment  1743  of the wall  1740  may be offset relative to a second segment  1744  of the wall, such that the first segment  1743  defines a recess. The second segment  1744  of the wall may be at a position in the y direction of the device that would contact, interfere with, or otherwise be too close to the protruding portion  1742 . Accordingly, the first segment  1743  of the wall is positioned further away from the battery  1741  (e.g., it defines a recess), such that the protruding portion  1742  does not contact or otherwise interfere with the wall  1740 . In some cases, the minimum distance between the wall  1740  and the battery  1741  is less than about 1 mm. The minimum distance may be defined between the protruding portion  1742  of the battery and the first segment  1743  of the wall. 
       FIG.  18 A  depicts a cross-sectional view of a device through a portion of a rear-facing sensor array (e.g., the sensor array  141 ,  FIG.  1 D ) that includes a depth sensor module. The depth sensor module may include an emitter assembly  1822  and a sensor assembly  1820 . A cover lens  1824  may be positioned on or over the emitter assembly  1822 . The emitter assembly  1822  and sensor assembly  1820  may include lens assemblies, light emitters, light sensors, and the like. 
     For example, the emitter assembly  1822  is adapted to emit one or more beams of light, such as coherent light beams having a substantially uniform wavelength/frequency (e.g., infrared laser light). The sensor assembly  1820  may detect beams of light that are emitted by the emitter assembly  1822  and reflected by an object external to the device. The depth sensor module may determine, based on time-of-flight measurements for example, a distance to an object based on the reflected light detected by the sensor assembly  1820 . 
     The sensor assembly  1820  and emitter assembly  1822  may be coupled to a substrate  1818  (e.g., a circuit board), and may be held in place by a frame member  1816 . The sensor assembly  1820 , emitter assembly  1822 , circuit board  1818 , and frame member  1816  (and optionally other components) may be at least partially enclosed in an enclosure, which may include a first enclosure member  1812  and a second enclosure member  1814 . 
     The depth sensor may generally define a snout portion  1809 . The snout portion  1809  may have a height that is less than the depth of an opening  1807  in the rear cover  1802 . More particularly, the depth sensor may be positioned in a thickened region  1826  of the rear cover  1802 , where the thickened region  1826  corresponds to or defines the rear-facing sensor array (and is thicker than a main portion  1827  of the rear cover  1802 ). As such, the end of the snout portion  1809  may be recessed relative to the top surface of the rear cover  1802 . However, an air gap between the emitter and sensor assemblies  1822 ,  1820  and the cover  1804  may be detrimental to performance of the depth sensor. Accordingly, a transparent interposer structure  1810  may be positioned between the snout portion  1809  of the depth sensor module and the underside of the cover  1804 . The interposer structure  1810  may include a lens portion  1825  that is positioned between the cover  1804  and the snout portion  1809 . The lens portion  1825  reduces the size of the air gap between the snout portion  1809  and the cover  1804 , and may therefore reduce the extent to which the light emitted by the emitter assembly  1822  disperses (e.g., angles away from a centerline of the emitter assembly  1822 ) prior to the light exiting the device through the cover  1804 . 
     The interposer may include flanges that are adhered to the first enclosure member  1812  and to the rear cover  1802 . The lens portion  1825  may also be adhered to the cover  1804  via an optically clear adhesive  1806 . In some cases, the cover  1804 , the optically clear adhesive  1806 , and the lens portion  1825  of the interposer may have the same or substantially similar index of refraction. For example, in some cases the indices of refraction of the cover  1804 , the optically clear adhesive  1806 , and the lens portion  1825  differ by less than about 5%. In some cases, the cover  1804 , the optically clear adhesive  1806 , and the lens portion  1825  each have a refractive index between about 1.7 and about 1.8. 
     A sealing member  1808  (e.g., an O-ring) may form an environmental and/or light seal between the interposer structure  1810  and the inner wall of the hole  1807  defined through the rear cover  1802 . In some cases, an infrared-transparent, visually opaque coating may be applied to the cover  1804  (e.g., to an inner surface of the cover  1804  and adjacent the adhesive  1806 ). The interposer structure  1810  may be formed from a transparent material, such as glass, a polymer (e.g., polycarbonate), sapphire, or the like. 
       FIG.  18 B  depicts a cross-sectional view of a device through a portion of a rear-facing sensor array (e.g., the sensor array  141 ,  FIG.  1 D ) that includes a depth sensor module.  FIG.  18 B  depicts another example configuration for integrating the depth sensor module of  FIG.  18 A  into a device. As noted with respect to  FIG.  18 A , the depth sensor may generally define a snout portion  1809  that has a height that is less than the depth of an opening  1807  in the rear cover  1802 . More particularly, the depth sensor may be positioned in a thickened region  1826  of the rear cover  1802 , where the thickened region  1826  corresponds to or defines the rear-facing sensor array (and is thicker than a main portion  1827  of the rear cover  1802 ). As such, the end of the snout portion  1809  may be recessed relative to the top surface of the rear cover  1802 . While  FIG.  18 A  illustrates an interposer structure  1810  that defines a lens portion  1825 , the example in  FIG.  18 B  includes a depth sensor mounting bracket  1834 , and a separate cover member  1830  that is positioned in the opening  1807  of the rear cover  1802  and is coupled to (e.g., via adhesive  1832 ) the mounting bracket  1834 . The mounting bracket  1834  may include flanges that are adhered to the first enclosure member  1812  and to the rear cover  1802 . The mounting bracket  1834  may be formed from metal (e.g., aluminum, steel, etc.), a polymer, or any other suitable material. 
     The cover  1830  may have a thickness that is substantially equal to the combined thickness of cover  1804 , adhesive  1806 , and lens portion  1825  in  FIG.  18 A . Further, the thickness of the cover  1830  may be greater than the covers positioned over rear-facing cameras that are also part of the rear-facing sensor array. The thick cover  1830  may reduce or minimize any air gap between the snout portion  1809  and the cover  1830 , and may therefore reduce the extent to which the light emitted by the emitter assembly  1822  disperses (e.g., angles away from a centerline of the emitter assembly  1822 ) prior to the light exiting the device through the cover  1830 . The cover  1830  may be formed from sapphire, glass, plastic, or another suitable material. The cover  1830  may include one or more coatings, dyes, inks, layers, or other materials or treatments that render the cover  1830  visually opaque (e.g., opaque to at least some portions of light in the visible spectrum). While the cover  1830  may appear visually opaque, it may be at least partially transparent to light from the emitter assembly  1822  (e.g., to allow the depth sensor module to function, while also occluding the depth sensor module from visibility). 
       FIG.  18 C  illustrates another example cover assembly  1840  that may be used in place of the cover  1830  shown in  FIG.  18 B . In this case, instead of the monolithic cover  1830 , a cover assembly  1840  may include an outer cover  1842  that defines the exterior surface of the cover assembly  1840 , and an inner cover  1848 , coupled to the outer cover  1842  via an adhesive  1844 . The outer cover  1842  may be mounted to the mounting bracket  1834  via adhesive  1846 , and the inner cover  1848  may be positioned in the hole that is defined by the mounting bracket  1834 . In this example, the chimney-like structure of the mounting bracket  1834  to which the outer cover  1842  is coupled may be taller than the example shown in  FIG.  18 B  to accommodate the thinner outer cover  1842  and to position the exterior surface of the outer cover  1842  substantially flush with the exterior surface of the rear cover  1802  (e.g., the surface of the rear-facing sensor array). Further, because the inner cover  1848  is within the chimney-like structure of the mounting bracket  1834 , it may extend closer to the snout  1809  than the cover  1830  shown in  FIG.  18 B . 
     The inner cover  1848  may be adhered to the outer cover  1842  via an optically clear adhesive  1844 . In some cases, the inner cover  1848 , the optically clear adhesive  1844 , and the outer cover  1842  may have the same or substantially similar index of refraction. For example, in some cases the indices of refraction of the inner cover  1848 , the optically clear adhesive  1844 , and the outer cover  1842  differ by less than about 5%. In some cases, the inner cover  1848 , the optically clear adhesive  1844 , and the outer cover  1842  each have a refractive index between about 1.7 and about 1.8. The inner cover  1848  and outer cover  1842  may be formed of the same or different materials. Example materials of the inner cover  1848  and the outer cover  1842  include sapphire, glass, polymers (e.g., polycarbonate, acrylic, etc.), or the like. 
     The cover assembly  1840  may include one or more coatings, dyes, inks, layers, or other materials or treatments that render the cover assembly  1840  visually opaque (e.g., opaque to at least some portions of light in the visible spectrum). While the cover assembly  1840  may appear visually opaque, it may be at least partially transparent to light from the emitter assembly  1822  (e.g., to allow the depth sensor module to function, while also occluding the depth sensor module from visibility). 
       FIG.  19 A  depicts a partial cross-sectional view of a device through a portion of a rear-facing sensor array (e.g., the sensor array  141 ,  FIG.  1 D ), viewed along line  19 - 19  in  FIG.  1 D , for example.  FIG.  19 A  illustrates a first lens assembly  1904  of a camera (e.g., the second camera  144 ,  FIG.  1 D ) and a second lens assembly  1908  of another camera (e.g., the third camera  146 ,  FIG.  1 D ). 
     As shown in  FIG.  19 A , the second lens assembly  1908  is shorter than that of the first lens assembly  1904 . Accordingly, when positioned in the device (e.g., through the openings in the sensor region of the rear cover  1902 ), the first lens assembly  1904  extends a first distance into its hole, while the second lens assembly  1908  extends a second distance into its hole, the second distance less than the first distance. The terminal end of the second lens assembly  1908  is positioned further below the top surfaces of the cover windows  1906 ,  1912  (which may be substantially co-planar) than the first lens assembly  1904 . 
     In some cases, the second lens assembly  1908  is a wide angle lens (e.g., having a 120° or greater field of view). As such, because the second lens assembly  1908  is shorter (and/or is positioned more distant from the top surfaces of the covers  1906 ,  1912 ), if a cover  1912  over the second lens assembly  1908  were to have the same thickness as the cover  1906 , the second lens assembly  1908  may capture in its field of view a portion of the camera window trim  1911  that is attached to the rear cover  1902  and surrounds the opening of the second lens assembly  1908 . This may produce undesirable artifacts in the images captured by the camera or limit the usable field of view of the second lens assembly  1908 . Accordingly, the cover  1912  may be thicker than the cover  1906 , despite having a top surface that is substantially co-planar or flush with the top surface of the cover  1906 . The co-planarity of the two covers  1912  and  1906  may help to stabilize the device when the device is placed (face up) on a surface such as a table. In particular, if one of the covers were higher than another, the device may wobble or tip back and forth on a surface due to having only two points of contact between the device and the surface. By having both covers  1912 ,  1906  co-planar (e.g., protruding a same distance from the back cover of the device), the device may have three points of contact with the surface, thereby inhibiting tipping or wobbling on the surface. 
     The thickness of the cover  1912  may refract light entering the cover  1906 , as shown by ray trace  1914 , such that the full field of view of the second lens assembly  1908  may be used without capturing the window trim  1911  in the frame. In this way, the exterior surfaces of the cover windows  1906 ,  1912  may be substantially co-planar, while also accommodating the different heights (or positions) of the lens assemblies in the device, and also using the full field of view of the wide-angle lens. 
     In some cases, the positioning of the camera window trim  1911  helps reduce light interference from various sources. For example, the camera window trim  1911  may act as a lens hood to reduce flare from low-angle light sources, strobe or flash output, or the like. 
     The cover  1906  may have a thickness between about 0.2 mm and about 0.5 mm, while the cover  1912  may have a thickness between about 1.8 mm and about 2.5 mm. The covers  1906  and  1912  may be formed from the same material or different materials. The covers  1906  and  1912  may be formed from sapphire, glass, polycarbonate, acrylic, or any other suitable material. 
     Devices as described herein may include rear covers that are formed from a transparent material such as glass. Further, the rear covers may include a rear-facing sensor array region, in which rear-facing sensors such as cameras, depth sensors, microphones, or the like may be positioned. The rear-facing sensor array region of a rear cover may be a portion of the rear cover that has a greater thickness than a main portion of the rear cover. Further this region may define holes that receive and/or accommodate cameras, depth sensors, microphones, etc. Due to the transition in thickness and the transparency of the material of the rear cover, a direct line of sight may exist from a user to the sensors or other components of the rear sensor array. For example,  FIG.  19 B  is a partial cross-sectional view of a device, through a portion that includes a rear cover  1935  and a camera. The components and features described with respect to  FIG.  19 B  may be used in conjunction with any of the cameras described herein. The rear cover  1935  defines a main portion  1930  (defining a first surface), a sensor region portion  1934  having a greater thickness than the main portion  1930  (and defining a second surface), and a transition region  1932  extending from the main portion  1930  to the sensor region portion  1934 . The transition region  1932  may define a curved surface (or alternatively a flat surface) that extends from and joins the first surface (of the main potion  1923 ) and the second surface (of the sensor region portion  1934 ). Because the rear cover  1935  is formed of a transparent material (e.g., glass, sapphire, etc.), the transition region  1932  and/or the sensor region portion  1934  may allow a line of sight into the device, and specifically towards the structural components of or nearby a camera assembly. 
       FIG.  19 B  depicts an example configuration in which the visual path through the transition region  1932  and/or the sensor region portion  1934  is blocked. In the example shown, a lens assembly  1920  of a camera is positioned below a cover  1922 . The cover  1922  is attached to a first trim ring  1924 , which may be coupled to a second trim ring  1936 . In some cases, a first sealing member  1926  (e.g., an O-ring) may be positioned between the first and second trim rings  1924 ,  1936 , and a second sealing member  1928  (e.g., an O-ring) may be positioned between the second trim ring  1936  and the rear cover  1935 . The first and second sealing members  1926 ,  1928  may inhibit ingress of water, dust, or other contaminants into the device. Because the sealing member  1928  contacts the vertical wall of the rear cover  1935  (e.g., the wall that defines the hole for the camera assembly), the sealing member  1928  may be visible through the transition region  1932  and/or the sensor region portion  1934  of the rear cover  1935 . Accordingly, the sealing member  1928  may have a color that is the same as or similar to the color of the second trim ring  1936 . For example, the sealing member  1928  and the second trim ring  1936  may both be black. Other colors are also contemplated for both of these components (e.g., silver, white, grey, etc.). 
     In order to block the line of sight into the device, the device may include one or more blocking features. For example, as shown in  FIG.  19 B , the second trim ring  1936  may define an extended wall portion  1938  that extends from an exterior surface of the rear cover  1935  (e.g., the exterior surface of the raised sensor array region of the rear cover  1935 ) to the interior surface  1942  of the rear cover  1935  (e.g., an end surface of the extended wall  1938  is substantially flush with the interior surface  1942  of the rear cover  1935 ). The extended wall  1938  blocks the line of sight through the vertical wall (of the rear cover  1935 ) that defines the hole, thus occluding the visibility of internal components such as a frame structure  1944  (or, if the frame structure  1944  were omitted, the lens assembly  1920  and/or other internal components of the device). More particularly, the extended wall  1938  blocks light that passes through the hole surface. The second trim ring  1936  may also include a flange portion  1937  extending from the wall  1938  and contacting the exterior surface of the raised sensor array region. The flange portion  1937  also defines an opening, in which a cover window and optionally the first trim ring may be positioned. 
     An opaque mask  1940  may be included on at least a portion the interior surface  1942  of the rear cover  1935  to block the line of sight through the interior surface  1942 . The opaque mask  1940  may be an ink, dye, film, paint, adhesive foam, or any other suitable material(s) that occlude the visibility of internal components through the interior surface  1942 . In some cases, the opaque mask  1940  is only applied to a region of the interior surface  1942  that is proximate the camera hole (e.g., such that all or a substantial portion of the main portion  1930  of the rear cover  1935  does not include the opaque mask  1940 . 
       FIG.  19 C  depicts another example configuration in which the visual path through the transition region  1932  and/or the sensor region portion  1934  is blocked.  FIG.  19 C  includes numerous example techniques that may be used to reduce the visibility into the device through the rear cover, though not all of these example techniques are necessarily implemented in the same device. In the example shown in  FIG.  19 C , a lens assembly of a camera may be positioned below a cover  1950 . The cover  1950  is attached to a first trim ring  1952 , which may be coupled to a second trim ring  1958 . In some cases, a first sealing member  1954  (e.g., an O-ring) may be positioned between the first and second trim rings  1952 ,  1958 , and a second sealing member  1956  (e.g., an O-ring) may be positioned between the second trim ring  1958  and the rear cover  1935 . The first and second sealing members  1954 ,  1956  may inhibit ingress of water, dust, or other contaminants into the device. 
     Whereas the second trim ring  1936  in  FIG.  19 B  had an extended wall that blocked the line of sight through the vertical wall that defines the hole for the camera, the second trim ring  1958  in  FIG.  19 C  does not extend fully to the interior surface. Accordingly, an opaque mask  1972  may be included on at least a portion of the vertical wall (e.g., the surface of the hole formed through the rear cover) to block the line of sight through the vertical wall. The opaque mask  1972  may be an ink, dye, film, paint, adhesive foam, or any other suitable material(s) that occlude the visibility of internal components through the vertical wall. In some cases, instead of or in addition to the opaque mask  1972 , the vertical wall may have a surface treatment (e.g., a surface texture) that renders the vertical wall translucent. In some cases, a surface texture of the vertical wall is characterized by a surface roughness value (R a ) of between about 1.5 microns and about 10 microns. 
     In some cases, instead of or in addition to the opaque mask  1972 , a bracket  1970  may be positioned along (and either contacting or set apart from) a portion of the vertical wall of the rear cover  1935  and at least a portion of the interior surface of the rear cover  1935 . The bracket  1970  may block the line of sight through these portions of the rear cover  1935 . The bracket  1970  may be formed from any suitable material (e.g., metal, polymer, etc.). The bracket  1970  may be opaque, and/or may have a color that reduces the noticeability of the bracket  1970  itself (e.g., a color that matches nearby components, a dark and/or matte color that absorbs light and hides or minimizes visible features, etc.). The bracket  1970  may include an ink, dye, film, paint, or the like, to provide the color. In some cases, the bracket  1970  is attached to one or both of the vertical wall or the interior surface of the rear cover via an adhesive. 
     In some cases, such as examples where the mask  1972  and/or the bracket  1970  are not included, a mask  1968  may be positioned on an internal component  1974  (e.g., a frame member) that may otherwise be visible through the rear cover  1935 . The internal component  1974  may define a first portion extending along an interior surface of the rear cover, and a second portion extending at least partially into the hole in which the trim rings and camera components are at least partially positioned. In some cases, the second portion of the internal component  1974  may at least partially overlap the wall portion of a trim ring. The mask  1968  may be positioned along at least a portion of each of the first and second portions of the internal component  1974 , and may be configured to reduce the visibility or noticeability of the component  1974  to which the mask  1968  is applied. The mask  1968  may be opaque, and/or may have a color that reduces the noticeability of the component (e.g., a color that matches nearby components, a dark and/or matte color that absorbs light and hides or minimizes visible features, etc.). The mask  1968  may be an ink, dye, film, paint, adhesive foam, or any other suitable material(s). 
     In some cases, an opaque mask  1966  may be included on at least a portion of the interior surface of the rear cover  1935  to block the line of sight through the interior surface. The opaque mask  1966  may be an ink, dye, film, paint, adhesive foam, or any other suitable material(s) that occlude the visibility of internal components through the interior surface. In some cases, the opaque mask  1966  is only applied to a region of the rear cover  1935  that is proximate the camera hole (e.g., such that all or a substantial portion of the main portion  1930  of the rear cover  1935  does not include the opaque mask  1966 . 
     In some cases, instead of or in addition to the techniques described with respect to  FIGS.  19 B and  19 C  for occluding the line of sight into the device through the transition region  1932 , the transition region  1932  (and/or other portions of the rear cover) may include a surface texture that renders the exterior surface of the transition region  1932  translucent. The surface texture may be formed using laser etching, chemical etching, abrasive blasting, grinding, or any other suitable technique. 
       FIGS.  19 B- 19 C  illustrate an example camera configuration that includes two trim rings (e.g., first and second trim rings  1924 ,  1936  in  FIG.  19 B , and first and second trim rings  1952  and  1958  in  FIG.  19 C ). While other example camera systems shown herein may include only one trim piece, it will be understood that the configurations shown in  FIGS.  19 B- 19 C  may be applied to any devices and/or cameras shown or described herein. 
     As noted above, the devices described herein may include a flash (e.g., a light source) that is configured to illuminate a scene to facilitate capturing images with one or more cameras of the electronic device. The flash, also referred to as a flash module or more broadly a light source, may include one or more light emitting diodes (LEDs) that produce the light to illuminate the scene. The flash module may be part of or positioned proximate a sensor array to facilitate illumination of scenes for flash photography. 
       FIG.  20 A  illustrates a back view of a flash module  2000  (e.g., the side of the flash module that faces the interior of the device) that may be used with the devices described herein. For example, the flash module may be part of the rear-facing sensor array of a device. The flash module  2000  may include a carrier  2001  and a circuit board  2002 . The circuit board  2002  may be attached to the carrier  2001 , and the carrier  2001  may be secured to the device (e.g., in an opening or proximate a window in a rear cover of the device). 
     The circuit board  2002  may include electrical contact pads  2004  and  2006  arranged in a generally circular arrangement. For example, the circuit board  2002  may include a set of first contact pads  2004  arranged in a first generally circular arrangement (e.g., along a circle having a first diameter), and a set of second contact pads  2006  arranged in a second generally circular arrangement (e.g., along a circle having a second diameter that is larger than the first diameter) and around the set of first contact pads  2004 . The set of first contact pads  2004  and/or the set of second contact pads  2006  may be spaced evenly about their respective circles (e.g., having a same distance between any two adjacent contact pads). 
     The set of first contact pads  2004  may be used to conductively couple the LEDs (and/or other circuitry, processors, or other electrical components) of the flash module  2000  to other circuitry and/or components of a device. Thus, wires, traces, leads, or other conductive elements may be soldered, welded, or otherwise conductively coupled to the set of first contact pads  2004 . The set of second contact pads  2006  may also be conductively coupled to the LEDs (and/or other circuitry, processors, or other electrical components) of the flash module  2000 , and may be provided to facilitate testing of the flash module without having to make physical contact with the set of first contact pads  2004 , thereby avoiding potential damage or contamination of the set of first contact pads  2004 . 
       FIG.  20 B  is a partial cross-sectional view of the flash module  2000 , viewed along line  20 B- 20 B in  FIG.  20 A , showing an example integration of the circuit board  2002  with the carrier  2001 . The carrier  2001  may be a single unitary piece of light transmissive material, such as glass, a light-transmissive polymer, sapphire, or the like. 
     The carrier  2001  may define a ledge  2014 , which may define a recess in which the circuit board  2002  is positioned. For example, the ledge  2014  may be recessed relative to a back surface  2012  of the carrier  2001 . The ledge  2014  may be recessed from the back surface  2012  a distance that is substantially equal to the thickness of the circuit board  2002  or is otherwise configured based on a dimension of the circuit board  2002  such that the back of the circuit board  2002  is flush with or recessed relative to the back surface  2012  of the carrier  2001 . The circuit board  2002  may be attached to the carrier  2001  via an adhesive (e.g., between the ledge  2014  and the circuit board  2002 ). 
     In some cases, a coating  2007 , such as an ink, mask, dye, paint, film, a vapor deposition coating (e.g., chemical or plasma vapor deposition), or the like, may be applied to the back surface  2012 . In some cases, the coating  2007  is an opaque white coating. In other cases, the coating  2007  is a mirror-like reflective coating (e.g., a silver PVD or CVD coating). The coating  2007  may prevent or limit the visibility of internal components of a device through the material of the carrier  2001 , and may help avoid the presence of a black or dark ring-like appearance around the perimeter of the flash module  2000  (e.g., when the external-facing surface of the flash module  2000  is viewed when the flash module  2000  is integrated with a device). 
       FIG.  20 B  also shows light emitting elements  2008  and  2010  (e.g., LEDs) attached to the circuit board  2002  and configured to emit light downward, towards a lens portion  2016  of the carrier  2001 . The lens portion  2016  may be or define a Fresnel lens (or other type of lens) that focuses, diffuses, or otherwise changes the light to produce a desired spread or illumination angle. The lens portion  2016  may be integrally formed into the carrier  2001  (e.g., the material of the carrier  2001  may define the lens portion  2016 ). In some cases, the lens portion  2016  may be a separate element that is attached to the carrier  2001 . 
     The carrier  2001  may also define a recess  2018  in a sidewall to receive a compliant member  2020 . The compliant member  2020  may be an O-ring (or other suitable compliant member) and may be configured to form an environmental seal between the carrier  2001  and part of the housing of the device in which it is integrated (e.g., the surfaces of a hole or recess in a rear cover of a device). 
       FIG.  20 C  is a partial cross-sectional view of a flash module  2030 , showing a view similar to that of  FIG.  20 B . The flash module  2030  includes a differently configured carrier  2031  and compliant member  2034 . In particular, the carrier  2031  may define a shaped recess  2032  in a sidewall, and the shaped recess  2032  is configured to receive a shaped compliant member  2034 . The shaped compliant member  2034  may be molded in place in the recess  2032 . For example, a flowable material, such as a polymer material, may be introduced into the shaped recess  2032  and allowed to at least partially cure to form the compliant member  2034 . An external mold or other tool may surround the carrier  2031  during the polymer introduction and/or injection process to form the shape of the exterior surfaces of the compliant member  2034 . 
     The shaped compliant member  2034  (and the shaped recess  2032 ) may extend further into the sidewall of the carrier  2031  than the compliant member  2020  and the recess  2018  in  FIG.  20 B . This configuration may allow the compliant member  2034 , which may be opaque, to occlude or otherwise block the appearance of the internal components of the flash module  2030  and the internal components of a device more generally. For example, the shaped compliant member  2034  extends into the sidewall of the carrier  2031  such that there is a distance  2027  between the end of the shaped compliant member  2034  and the outer perimeter of the lens portion  2033  of the carrier  2031 . By contrast, as shown in  FIG.  20 B , the compliant member  2020  may extend a shorter distance into the sidewall, resulting in a distance  2022  (which is greater than the distance  2027 ), thereby potentially allowing more visibility into the internals of the flash module and the device. The greater depth of the shaped recess  2032  and the increased size and the contoured shape of the compliant member  2034  may also result in a more dimensionally stable compliant member  2034  that can stay in a desired position through greater forces and deflections, as compared to an O-ring for example. 
     As with the carrier  2001 , the carrier  2031  may be a single unitary piece of light transmissive material, such as glass, a light-transmissive polymer, sapphire, or the like. The flash module  2030  may also include the circuit board  2002  and the light emitting elements  2008  and  2010  (e.g., LEDs), and the circuit board  2002  may be attached to the carrier  2031  in the same or similar manner as the flash module  2030 . 
       FIG.  20 D  is a partial cross-sectional view of a flash module  2036 , showing an example integration of the flash module  2036  into a rear cover  2037  of an electronic device. The flash module  2036  may be positioned in a hole formed in a rear-facing sensor array defined by the rear cover  2037 . The flash module  2036  includes a circuit board  2038  and light emitting elements  2039  (e.g., LEDs) attached to the circuit board  2038  and configured to emit light downward, towards a carrier  2041 . The carrier  2041  may define a lens portion, such as a Fresnel lens (or other type of lens) that focuses, diffuses, or otherwise changes the light to produce a desired spread or illumination angle. The carrier  2041  (and the lens portion it defines) may be formed from a transparent material such as glass, polymer, polycarbonate, acrylic, or the like. 
     The flash module  2036  may also include a trim piece  2040  that surrounds the carrier  2041 , and to which the carrier  2041  may be attached. For example, the carrier  2041  may be attached to the trim piece  2040  via an adhesive  2042 . A sealing member  2044 , such as an O-ring or other compliant member, may be positioned at least partially in a recess in the trim piece  2040 , and may contact the trim piece  2040  and a surface of the rear cover  2037  that defines the hole in which the flash module  2036  is positioned. The sealing member  2044  may form an environmental seal between the trim piece  2040  and the rear cover  2037 . 
     The trim piece  2040  may be opaque (e.g., it may be formed from an opaque material, or coated, painted, or otherwise treated to be opaque). The opaque trim piece  2040  may inhibit or prevent light emitted by the light emitting elements  2039  from entering the rear cover  2037 , such as through the surfaces of the rear cover  2037  that define the hole in which the flash module  2036  is positioned. For example, light leakage into the rear cover  2037  through the hole surfaces may leak out of the rear cover  2037  near cameras or other light-sensitive components of the rear-facing sensor array, which may interfere with the operation of those components. As one specific example, light leakage may cause pictures captured by a rear-facing camera to have a hazy appearance that reduces the quality of the pictures. As another example, rear-facing depth sensors may not be able to properly make depth measurements due to the interference from such light leaks. Accordingly, the opaque trim piece  2040  may reduce or eliminate such light leakage. The trim piece  2040  may be a metal, polymer, or any other suitable material. 
     As shown in  FIG.  20 D , an exterior surface  2035  of the carrier  2041  may be recessed a distance  2043  relative to an exterior surface  2045  of the rear cover  2037 . The exterior surface  2065  of the trim piece  2040 , which is opaque, prevents light that is emitted from the recessed surface  2035  from entering the rear cover  2037 . Further, the angle of the exterior surface  2065  of the trim piece  2040  (which may have a conical shape) may define the pattern of illumination produced by the flash module  2036 . The pattern of illumination may be configured to illuminate a particular field of view that coincides with a target field of view of a camera of the rear-facing sensor array. The target field of view may be a particular distance from a camera of the rear-facing sensor array, at a particular magnification level for that camera. 
       FIG.  20 E  is a partial cross-sectional view of another example flash module  2046 , showing an example integration of the flash module  2046  into a rear cover  2047  of an electronic device. The flash module  2046  may be positioned in a hole formed in a rear-facing sensor array defined by the rear cover  2047 . The flash module  2046  includes a circuit board  2048  and light emitting elements  2049  (e.g., LEDs) attached to the circuit board  2048  and configured to emit light downward, towards a carrier portion  2051 . The carrier portion  2051  may define a lens, such as a Fresnel lens (or other type of lens) that focuses, diffuses, or otherwise changes the light to produce a desired spread or illumination angle. The carrier portion  2051  (and the lens portion it defines) may be formed from a transparent material such as glass, polymer, polycarbonate, acrylic, or the like. 
     The flash module  2046  may also include a trim portion  2050  that surrounds the carrier portion  2051 . While the trim piece  2040  and carrier  2041  in  FIG.  20 D  were two separately manufactured components that were attached together, the trim portion  2050  and the carrier portion  2051  in  FIG.  20 E  may be manufactured using a two-shot molding process. In particular, a first material (e.g., a transparent polymer material) may be introduced into a mold to form the carrier portion  2051 , and subsequently a second material (e.g., an opaque polymer material) may be introduced into the mold and against the first material to form the trim portion  2050 . The combination carrier portion and trim portion may then be removed from the mold as a single component. In some cases, the order in which the first and second materials are introduced into the mold may be reversed. The first and second materials may be different materials (e.g., different polymers), or they may be transparent and opaque versions of the same material. By forming the carrier portion  2051  and trim portion  2050  as a single component, assembly time and complexity may be reduced relative to a multi-part assembly. 
     A sealing member  2054 , such as an O-ring or other compliant member, may be positioned at least partially in a recess in the trim portion  2050 , and may contact the trim portion  2050  and a surface of the rear cover  2047  that defines the hole in which the flash module  2046  is positioned. The sealing member  2054  may form an environmental seal between the trim portion  2050  and the rear cover  2047 . 
     As noted above, the trim portion  2050  may be opaque. The opaque trim portion  2050  may inhibit or prevent light emitted by the light emitting elements  2049  from entering the rear cover  2047 , such as through the surfaces of the rear cover  2047  that define the hole in which the flash module  2046  is positioned. Accordingly, the opaque trim portion  2050  may reduce or eliminate such light leakage. 
     As shown in  FIG.  20 E , an exterior surface  2055  of the carrier portion  2051  may be recessed a distance  2053  relative to an exterior surface  2052  of the rear cover  2047 . The exterior surface  2076  of the trim portion  2050 , which is opaque, prevents light that is emitted from the recessed surface  2055  from entering the rear cover  2037 . Further, the angle of the exterior surface  2076  of the trim portion  2050  (which may have a conical shape) may define the pattern of illumination produced by the flash module  2046 . The pattern of illumination may be configured to illuminate a particular field of view that coincides with a target field of view of a camera of the rear-facing sensor array. The target field of view may be a particular distance from a camera of the rear-facing sensor array, at a particular magnification level for that camera. 
       FIG.  20 F  is a partial cross-sectional view of another flash module  2056 , showing an example integration of the flash module  2056  into a rear cover  2057  of an electronic device. The flash module  2056  may be positioned in a hole formed in a rear-facing sensor array defined by the rear cover  2057 . The flash module  2056  includes a circuit board  2058  and light emitting elements  2059  (e.g., LEDs) attached to the circuit board  2058  and configured to emit light downward, towards a carrier  2061 . The carrier  2061  may define a lens portion, such as a Fresnel lens (or other type of lens) that focuses, diffuses, or otherwise changes the light to produce a desired spread or illumination angle. The carrier  2061  (and the lens portion it defines) may be formed from a transparent material such as glass, polymer, polycarbonate, acrylic, or the like. 
     The flash module  2056  may also include a trim piece  2060  that surrounds the carrier  2061 , and to which the carrier  2061  may be attached. For example, the carrier  2061  may be attached to the trim piece  2060  via an adhesive. A sealing member  2064 , such as an O-ring or other compliant member, may be positioned at least partially in a recess in the trim piece  2060 , and may contact the trim piece  2060  and a surface of the rear cover  2057  that defines the hole in which the flash module  2056  is positioned. The sealing member  2064  may form an environmental seal between the trim piece  2060  and the rear cover  2057 . 
     The trim piece  2060  may be opaque (e.g., it may be formed from an opaque material, or coated, painted, or otherwise treated to be opaque). The opaque trim piece  2060  may inhibit or prevent light emitted by the light emitting elements  2059  from entering the rear cover  2057 , such as through the surfaces of the rear cover  2057  that define the hole in which the flash module  2056  is positioned. For example, light leakage into the rear cover  2057  through the hole surfaces may leak out of the rear cover  2057  near cameras or other light-sensitive components of the rear-facing sensor array, which may interfere with the operation of those components. Accordingly, the opaque trim piece  2060  may reduce or eliminate such light leakage. The trim piece  2060  may be a metal, polymer, or any other suitable material. 
     The flash module  2056  also includes a cover  2062  positioned over the exterior surface of the carrier  2061  and defining an exterior surface of the device. The cover  2062  may be formed from glass, sapphire, a polymer (e.g., polycarbonate, acrylic), or the like. The cover  2062  may be attached to the trim piece  2060  via an adhesive  2063 . The cover may help prevent liquid, debris, or other materials from becoming caught in the recess defined by the exterior surface of the carrier  2061  and the walls of the trim piece  2060 . In some cases, the adhesive  2063  is an opaque adhesive that hides the trim piece  2060  from view through the cover  2062 . In other cases, an opaque material (e.g., an ink, dye, paint, film, layer, etc.) is applied to the adhesive  2063 , the trim piece  2060 , and/or the cover  2062  to block the trim piece  2060 . 
       FIG.  20 G  is a partial cross-sectional view of another example flash module  2066 , showing an example integration of the flash module  2066  into a rear cover  2067  of an electronic device. The flash module  2066  may be positioned in a hole formed in a rear-facing sensor array defined by the rear cover  2067 . The flash module  2066  includes a circuit board  2068  and light emitting elements  2069  (e.g., LEDs) attached to the circuit board  2068  and configured to emit light downward, towards a carrier portion  2071 . The carrier portion  2071  may define a lens, such as a Fresnel lens (or other type of lens) that focuses, diffuses, or otherwise changes the light to produce a desired spread or illumination angle. The carrier portion  2071  (and the lens portion it defines) may be formed from a transparent material such as glass, polymer, polycarbonate, acrylic, or the like. 
     The flash module  2066  may also include a trim portion  2070  that surrounds the carrier portion  2071 . Similar to the trim portion  2050  and the carrier portion  2051  in  FIG.  20 E , the trim portion  2070  and the carrier portion  2071  may be manufactured using a two-shot molding process. In particular, a first material (e.g., a transparent polymer material) may be introduced into a mold to form the carrier portion  2071 , and subsequently a second material (e.g., an opaque polymer material) may be introduced into the mold and against the first material to form the trim portion  2070 . The combination carrier portion and trim portion may then be removed from the mold as a single component. In some cases, the order in which the first and second materials are introduced into the mold may be reversed. The first and second materials may be different materials (e.g., different polymers), or they may be transparent and opaque versions of the same material. By forming the carrier portion  2071  and trim portion  2070  as a single component, assembly time and complexity may be reduced relative to a multi-part assembly. 
     A sealing member  2074 , such as an O-ring or other compliant member, may be positioned at least partially in a recess in the trim portion  2070 , and may contact the trim portion  2070  and a surface of the rear cover  2067  that defines the hole in which the flash module  2066  is positioned. The sealing member  2074  may form an environmental seal between the trim portion  2070  and the rear cover  2067 . 
     As noted above, the trim portion  2070  may be opaque. The opaque trim portion  2070  may inhibit or prevent light emitted by the light emitting elements  2069  from entering the rear cover  2067 , such as through the surfaces of the rear cover  2067  that define the hole in which the flash module  2066  is positioned. Accordingly, the opaque trim portion  2070  may reduce or eliminate such light leakage. 
     As described herein, devices such as mobile phones may include logic boards, which may include processors, memory, and other electrical circuitry that control the device and/or portions of the device.  FIG.  21 A  depicts an example logic board  2100  for a device. The logic board  2100  may correspond to or be an embodiment of the logic board  220 ,  320 , or any other logic board described herein. 
     The logic board  2100  includes a first substrate  2102  and a second substrate  2104  supported above the first substrate  2102 . The first and second substrates  2102 ,  2104  may also be referred to as circuit boards. Electrical components and/or circuit elements such as processors, memory, antenna circuitry, and the like, may be coupled to the first and/or the second substrates  2102 ,  2104 . 
     The first and second substrates  2102 ,  2104  may be connected to one another via a wall structure  2106  (which supports the second substrate  2104  above the first substrate  2102 ). As described herein the first and second substrates  2102 ,  2104  may be soldered to conductive members (e.g., vias) in the wall structure  2106 , thereby allowing components on the first and second substrates  2102 ,  2104  to be conductively coupled to one another via the wall structure  2106 . The wall structure  2106  may also surround electrical components (e.g., a processor) and, along with the first and second substrates  2102 ,  2104 , define a substantially enclosed and optionally sealed internal volume in which the processor (and/or other components) may be protected. 
     The logic board  2100  may be structurally mounted to a housing member or other structure of a device to secure the logic board  2100 . To facilitate the structural mounting, the logic board  2100  may include a tab portion  2108  of an attachment member  2107 , which may be attached to a post (e.g., the post  2114 ,  FIG.  21 B ) or other structural component (e.g., via a fastener extending through a hole in the tab portion). The logic board  2100  may also include a notch region  2113  that exposes the first substrate  2102  so that a fastener may secure the logic board to a post or other structural component via the first substrate  2102 . 
     The logic board  2100  may also act as a structural mounting point for other components of the device. Accordingly, mounting features may be provided on the logic board  2100  for both mounting the logic board  2100  to other components and for mounting other components to the logic board. For example,  FIG.  21 A  shows a mounting stud  2110  attached to the second substrate  2104 , and a tab portion  2108  extending from a side of the logic board  2100 . As described herein, the mounting stud  2110  may be used to secure another component to the logic board  2100 , while the tab portion  2108  is used to secure the logic board  2100  to a housing structure or other component of a device. 
       FIG.  21 B  illustrates a side (and partially cut-away) view of a portion of the logic board  2100 , showing example configurations for the mounting stud  2110  and the tab portion  2108 . The mounting stud  2110  may be attached to a top surface of the second substrate  2104 . The mounting stud  2110  may be attached to the second substrate  2104  via a soldering, welding, adhesive, or the like. Notably, the mounting stud  2110  does not extend into or through the second substrate  2104 . In this way, the mounting stud  2110  does not impart any clamping, compression, or other such forces to the logic board. For example, in other implementations, a mounting point was provided by a fastener that extended through both the first and second substrates and was secured to the logic board with a clamping force. The mounting stud  2110  shown in  FIGS.  21 A and  21 B , by contrast, provides a mounting point without imparting a compressive stress on the substrates, thereby reducing the risk of potential damage to the logic board due to over-tightening or otherwise generally constricting the logic board. 
       FIG.  21 B  also illustrates an example configuration of an attachment member  2107  that may be used to attach the logic board  2100  to the device. For example,  FIG.  21 B  shows the tab portion  2108  secured to a post  2114  with a fastener (e.g., a screw)  2115  extending through a hole in the tab portion  2108 . The post may be secured to or part of a substrate  2112 , which may be a chassis (e.g., the chassis  219 ,  319 ) or any other suitable structure of a device. The tab portion  2108  may be attached to the logic board (e.g., to the first substrate  2102 ) via a mounting portion  2109 . The mounting portion  2109  may be attached to the first substrate  2102  in any suitable way, including soldering, welding, adhesives, or the like. The tab portion  2108  may provide a degree of compliance to the physical coupling of the logic board  2100  to the device. For example, the material of the tab portion  2108  (and mounting portion  2109  where those components are unitary) may be more resilient or flexible than the substrates themselves. Further, the shapes, dimensions, curvatures, thicknesses, and material properties of the tab portion  2108  may be selected to provide a target degree of compliance and/or flexibility. Accordingly, the tab portion  2108  may flex to reduce the effects of forces (e.g., shock loading) on the logic board  2100  due to drop events, impacts, or other forceful events to which the device may be subjected. 
       FIG.  21 C  illustrates another example configuration of an attachment member  2105  with a mounting portion  2124  and a tab portion  2122  that may be used to secure the logic board  2100  to the device. While the tab portion  2108  and the mounting portion  2109  in  FIG.  21 B  are different portions of a unitary structure with a substantially uniform thickness (e.g., a stamped metal attachment member), the unitary structure defining the tab portion  2122  and mounting portion  2124  of the attachment member  2105  may have a variable thickness. For example, the mounting portion  2124  may have a first thickness, the tab portion  2122  may have a second thickness different from the first thickness, and a joining portion  2126  may have a third thickness that is different from the first and second thicknesses. The particular thicknesses of the mounting portion  2124 , tab portion  2122 , and joining portion  2126  may be configured to provide target strength and flexibility parameters. For example, the joining portion  2126  may be thinner than the mounting portion  2124  and tab portion  2122  to provide increased flexibility and/or compliance, while the mounting portion  2124  and tab portion  2122  may be thicker to provider greater rigidity and strength. The greater flexibility of the joining portion  2126  may help reduce the effects of forces (e.g., shock loading) on the logic board  2100  due to drop events, impacts, or other forceful events to which a device may be subjected, while the thicker mounting portion  2124  provides greater strength and stiffness to the first substrate  2102 . The thicker (and stiffer) mounting portion  2124  also may improve the reliability of the bond between the mounting portion  2124  and the first substrate  2102  by ensuring that loads are evenly distributed throughout the bonding region between the mounting portion  2124  and the first substrate  2102 . The thicker (and stronger) tab portion  2122  may provide greater strength to help resist breaking or other damage. The variable-thickness attachment member  2105  may be formed by forging, molding, welding multiple layers together, or the like. 
       FIG.  21 D  illustrates another example technique for providing a mounting point on the logic board  2100  without imparting unwanted compressive forces onto the substrates  2102 ,  2104  and/or the wall structure  2106 . In particular, a fastener assembly  2119  may be configured to retain the first substrate to the second substrate and may include a first fastener element, such as a flanged nut  2116 , and a second fastener element, such as a fastener  2118 . A barrel portion of the flanged nut  2116  may be positioned in holes formed through the first and second substrates  2102 ,  2104  and the wall structure  2106 , while a flange portion of the flanged nut  2116  contacts an outer (e.g., bottom) surface of the second substrate  2104 . The holes through the first and second substrates  2102 ,  2104  and the wall structure  2106  may be aligned (e.g., having collinear cylindrical axes) and may have a same inner diameter. Because the barrel portion of the flanged nut  2116  extends through the holes in the first and second substrates  2102 ,  2104  and the wall structure  2106 , lateral motion (e.g., parallel to the outer surfaces of the substrates  2102 ,  2104 ) may be inhibited. 
     The flanged nut  2116  may have a height that is greater than the thickness of the combined first and second substrates  2102 ,  2104  and the wall structure  2106 . That is, a top portion of the barrel of the flanged nut  2116  may extend above the top surface of the second substrate  2104 , such that a flange portion of the fastener  2118 , when secured to the flanged nut  2116 , does not compress (or in some cases contact) the second substrate  2104 . In some cases, the flanged nut  2116  may have a height that is equal to the thickness of the combined first and second substrates  2102 ,  2104  and the wall structure  2106 . 
     The flange portion of the fastener  2118  may be seated against the end surface of the barrel of the flanged nut  2116 . In cases where the end surface of the barrel portion extends past the outer surface of the first substrate  2102 , the flange of the fastener  2118  does not contact the outer surface of the first substrate  2102 , and does not compress the logic board. 
     In cases where the end surface of the barrel portion is flush with the outer surface of the first substrate, the flange portion of the fastener  2118  may contact the surface of the first substrate  2102  but not compress it (e.g., not apply a force to the logic board beyond a threshold (e.g., an incidental or nominal) amount). Stated another way, the distance between a contact surface of the flange portion of the flanged nut  2116  and a contact surface of the flange portion of the fastener  2118 , when the fastener  2118  is secured to the flanged nut  2116 , is equal to a distance from the outer surface of the first substate  2102  to the outer surface of the second substrate  2104 . 
     The fastener  2118  may define a receptacle  2117 , which may be threaded, for receiving another fastener  2121  to secure a component (e.g., a metal shroud  2123 , or another component) to the logic board  2100 . Accordingly, a mounting point may be provided on the logic board  2100  without introducing a compressive stress on the logic board. In the implementation shown in  FIG.  21 D , a mounting portion  2111  may be configured so that it is not captured between the flanged nut  2116  and the first substrate  2102 . In some cases, the fastener  2118  does not have the receptacle  2117 . 
       FIG.  21 E  depicts the notch region  2113  of the logic board  2100 , illustrating how a compliant fastening system may be used to secure the logic board  2100  to a device. The notch region  2113  may be defined by a recess in the wall structure  2106  and the second substrate  2104 . The notch region exposes a portion of the first substrate  2102 , and a compliant brace  2130  may be mounted to an upper surface of the first substrate  2102 . More particularly, base plates  2132  of the compliant brace  2130  may be mounted to the upper surface of the first substrate  2102 , such as via soldering, welding, adhesives, fasteners, or the like (as shown by attachment element  2142 , which may be solder, an adhesive, a weldment, etc.). A reinforcement plate  2139  may be attached to a bottom surface of the first substrate  2102 . The compliant brace  2130  may be a unitary structure formed of metal or any other suitable material. 
     A fastener  2136 , such as a threaded screw or bolt, may extend through a hole in the compliant brace  2130 , through a hole or cutaway in the first substrate  2102 , and through a hole in the reinforcement plate  2139 , and may be coupled to a mounting feature such as a mounting boss  2140  ( FIG.  21 F ) to secure the logic board  2100  to the device.  FIG.  21 F  is a partial cross-sectional view of the notch region  2113 , and shows the fastener  2136  secured to the mounting boss  2140 , which is in turn attached to a component  2144  (which may be a housing component, rear cover, frame member, or any other structural component of a device). With reference to both  FIGS.  21 E and  21 F , the compliant brace  2130  is configured to allow the logic board  2100  to deflect upwards (as shown in  FIG.  21 F ) during drop events, impacts, or other forceful events to which the device may be subjected. For example, the loop portions  2134  and the top beam portion  2131  of the compliant brace  2130  may be configured to deflect, bend, or otherwise deform such that the first substrate  2102  (and thus the whole logic board  2100 ) can move in at least one direction. For example, in response to a first force (e.g., a force perpendicular to the main plane of the logic board  2100 ), the compliant brace may deflect to allow upwards movement of the logic board  2100  such that the reinforcing plate  2139  temporarily lifts off of the mounting boss  2140 . In this way, a degree of compliance and suspension may be provided to the logic board  2100 , which may reduce the magnitude and/or effect of shock loading or other potentially detrimental forces on the logic board  2100 . In some cases, the compliant brace also deflects, bends, or otherwise deforms to allow the logic board  2100  to move in a second direction, such as a lateral direction (e.g., left-to-right in  FIG.  21 F ) in response to a second force (e.g., a force that is parallel to the main plane of the logic board  2100 ). In some cases, the mounting boss  2140  inhibits downward movement of the logic board  2100 . 
     In some cases, the compliant brace  2130  is configured to be in a stressed condition when in a static condition, such as that shown in  FIG.  21 F . For example, when the fastener  2136  is threaded into the mounting boss  2140 , the fastener  2136  may slightly deform (e.g., compress) the compliant brace  2130 . In this way, the compliant brace  2130  may decouple the attachment force between the fastener  2136  and the mounting boss  2140  from the amount of force applied to the logic board  2100 . For example, the compliant brace  2130  may be clamped rigidly between the fastener  2136  and the mounting boss  2140  with a relatively high degree of clamping force to ensure that the logic board  2100  remains securely attached to the device. However, that amount of clamping force, if applied directly to the first substrate  2102  for example, may crush or unduly stress the first substrate  2102 . Accordingly, the compliant brace  2130  does not transfer all of the clamping load directly to the first substrate  2102 . Rather, the only force applied directly to the first substrate  2102  is that which results from any bending or compression of the compliant brace  2130  (as defined by the shape of the compliant brace  2130 , the mounting boss  2140 , and the thickness of the first substrate  2102  and the reinforcing plate  2139 , for example). In this way, the logic board  2100  may be secured to the housing with a high degree of security (e.g., due to the clamping force on the compliant brace  2130 , while still providing a high degree of compliance and a relatively low force applied directly to the first substrate  2102 . 
     In some cases, the compliant brace  2130  provides an electrical ground path between the logic board  2100  and a ground plane of the device. For example, the base plates  2132  of the compliant brace  2130  may be soldered to grounding solder pads on the first substrate  2102 , and the compliant brace  2130 , fastener  2136 , and mounting boss  2140  may define a conductive path to an electrical ground plane of the device. In some cases, the downwards bias produced by the compliant brace  2130  on the logic board  2100  helps force the logic board  2100  against an electrical ground plane (e.g., by biasing conductive grounding contacts against one another). 
       FIG.  21 G  illustrates another example logic board  2150 . The features described with respect to the logic board  2150  may be included in any other logic board described herein. 
     The logic board  2150  includes a first substrate  2152  and a second substrate  2154  supported above the first substrate  2152 . The first and second substrates  2152 ,  2154  may also be referred to as circuit boards. Electrical components and/or circuit elements such as processors, memory, antenna circuitry, and the like, may be coupled to the first and/or the second substrates  2152 ,  2154 . 
     The first and second substrates  2152 ,  2154  may be connected to one another via a wall structure  2156  (which supports the second substrate  2154  above the first substrate  2152 ). As described herein the first and second substrates  2152 ,  2154  may be soldered to conductive members (e.g., vias) in the wall structure  2156 , thereby allowing components on the first and second substrates  2152 ,  2154  to be conductively coupled to one another via the wall structure  2156 . The wall structure  2156  may also surround electrical components (e.g., a processor) and, along with the first and second substrates  2152 ,  2154 , define a substantially enclosed and optionally sealed internal volume in which the processor (and/or other components) may be protected. 
     The logic board  2150  may be structurally mounted to a housing member or other structure of a device to secure the logic board  2150 . In some cases, the logic board  2150  uses the same or similar mounting techniques as those described above with respect to the logic board  2100 . 
     The logic board  2150  may include an alignment feature  2160 . The alignment feature may be defined by recesses formed along an exterior side of each of the first and second substrates  2152 ,  2154  and the wall structure  2156 . The recesses may have the same size and shape, such that a single recess is defined along the side of the logic board  2150 . The alignment feature  2160  may be used when assembling the logic board  2150 . For example, a pin, rod, or other alignment tool may be positioned in the alignment feature  2160  and the alignment tool and the first and second substrates  2152 ,  2154  and the wall structure  2156  may be forced against each other with an alignment force. The alignment force may force the first and second substrates  2152 ,  2154  and the wall structure  2156  into contact with the alignment tool, thereby causing the recesses in the first and second substrates  2152 ,  2154  and the wall structure  2156  to become aligned, which, in turn, causes the first and second substrates  2152 ,  2154  and the wall structure  2156  to be aligned. Once aligned and retained in position by the alignment tool, the first and second substrates  2152 ,  2154  and the wall structure  2156  may be attached together, such as via soldering. In some cases, the alignment tool has a complementary shape and size as the recesses of the alignment feature  2160 . 
     In some cases, additional alignment features are also provided on the logic board  2150 , such as through-holes extending through the first and second substrates  2152 ,  2154  and the wall structure  2156  and configured to receive a rod or pin therein for alignment purposes. By forming the alignment feature  2160  along an outer or exterior edge of the logic board  2150 , the space requirement for the alignment feature  2160  may be less than the space requirement for through-holes, thereby allowing for more compact construction of the logic board  2150  and/or allowing more space on the logic board  2150  for other components. 
     The logic board  2150  also includes a clamp  2161  that may be used to help secure the logic board  2150  to a device.  FIG.  211    is a partial cross-sectional view of the logic board  2150 , showing details of the clamp  2161 . The clamp  2161  may include a base portion  2173  and a hook portion  2172  extending from the base portion  2173 . The hook portion  2172  hooks over the top of the second substrate  2154  and applies a clamping force to the second substrate  2154 . A fastener  2162 , such as a screw, may extend through a hole in the base portion  2173  and be anchored to a boss  2171  or other feature below the logic board  2150 . The boss  2171  may be attached to a structure of the electronic device, such as a chassis as described herein. The fastener  2162  may apply a downward force on the base portion  2173 , which in turn results in the hook portion  2172  applying the clamping force. The clamping force thus helps retain the logic board  2150  to the device. 
     In some cases, the logic board  2150  includes a shroud component  2163  on the top of the second substrate  2154 . The shroud component  2163  may be an EMF shield or other protective structure over a component (e.g., a processor) that is coupled to the second substrate  2154 . The shroud component may be formed of metal, plastic, or any other suitable material, and may define a lip structure  2170  that engages or otherwise overlaps the hook portion  2172  of the clamp  2161 . The lip structure  2170  may prevent or inhibit movement of the hook portion  2172  to maintain the hook portion  2172  in place (e.g., and prevent or inhibit the hook portion  2172  from slipping off of the top surface of the second substate  2154 ). In some cases, the shroud component  2163  may be omitted, and a lip or other retention feature (e.g., channel, groove, bump, etc.) may be defined by another component, such as a solder pad on the second substrate  2154 , the second substrate itself, a screw or other fastener, or the like. 
       FIG.  21 H  illustrates a detail view of a portion of the logic board  2150 , illustrating example techniques for securing the first and second substrates  2152 ,  2154  and the wall structure  2156  together. For example, the wall structure  2156  may include vias  2167  and the first and second substrates  2152 ,  2154  may include solder pads (represented by circles  2165 ) that are soldered to the vias  2167  to secure the first and second substrates  2152 ,  2154  and the wall structure  2156  together. The solder pads may include a first set of uniformly shaped solder pads  2165 , each having the same shape (e.g., circles as shown in  FIG.  21 H , though other shapes are also contemplated). In some cases, each solder pad  2165  may have a size, shape, and location such that it encompasses (and is ultimately soldered to) a certain number of vias  2167  (e.g., 3 vias, 4 vias, or any other suitable amount). The solder pads may also include one or more solder pads having a different shape than the first set of uniformly shaped solder pads  2165 . For example, the solder pad  2166  may have an irregular shape that encompasses (and is ultimately soldered to) a greater number of vias  2167  than the solder pads  2165  of the first set of solder pads (e.g., if the solder pads  2165  encompass three vias, the solder pad  2166  may encompass 4 or more vias). 
     In some cases, the first and second substrates  2152 ,  2154  each include a complementary set of matching solder pads (e.g., the solder pads shown in  FIG.  21 H  may be present on both the first and second substrates  2152 ,  2154 ). 
     In some cases, an underfill material  2169  may be introduced between the substrates and the wall structure and allowed to harden or cure to bond the substrates to the wall structure and/or reinforce the solder joints between the sub states and the wall structure. The underfill material  2169  may be an adhesive, epoxy, or any other suitable material. The underfill material  2169  may be introduced between a substrate and the wall structure  2156  after the substrate is soldered to the wall structure. The underfill material  2169  may flow or wick into the space between the substrate and the wall structure, and thereafter harden in place. In some cases, the logic board  2150  includes one or more features that help contain and/or guide the underfill material  2169  into the target areas between a substrate and the wall structure. For example, a pad  2164 , which may be a solder pad or a reinforcement plate on the first substrate  2152 , may act as a barrier wall to retain the underfill material  2169  during and after it is flowed below the wall structure  2156  and while it hardens. In some cases, the pad  2164  may cause the underfill material  2169  to build up along an outer side of the wall structure  2156 , forming a fillet of underfill material  2169  at the corner interface between the wall structure  2156  and the first substrate  2152 . Stated another way, the underfill material  2169  may extend part way up the outer surface of the wall structure to a height that is higher than the gap between the first substrate  2152  and the wall structure  2156 . By contrast, without the pad  2164 , the underfill material  2169  might have a maximum height that is equal to the gap between the first substrate  2152  and the wall structure  2156 , thereby providing less reinforcement to the interface between the first substrate  2152  and the wall structure  2156 . In some cases, other flow control features  2168  may provide a similar functionality along another side of the wall structure (e.g., inside the internal volume defined by the logic board  2150 ). The flow control features  2168  may be formed from any suitable material, such as solder, plastic, adhesive, or the like, and may serve the same or similar function as the pad  2164 . Flow control features such as the features  2168  and the pad  2164  may be used in various locations on the logic board  2150  to help guide and/or control the location of the underfill material. Further, such flow control features may be used between the first substrate  2152  and the wall structure  2156 , and between the second substrate  2154  and the wall structure  2156   
       FIG.  22 A  depicts a partial exploded view of a device  2200 , illustrating a battery  2202  separated from a rear cover  2204  (or other housing structure to which the battery may otherwise be coupled. The device  2200  may include an array of magnetic elements  2206  that are arranged in a circular or radial pattern. The magnetic elements  2206  may help to locate the device  2200  with respect to a separate wireless charging device or other accessory. In some implementations, the array of magnets also help to radially locate, orient, or “clock” the device  2200  with respect to the separate wireless charging device or other accessory. This functionality may be described as self-aligning or self-locating wireless charging. As shown in  FIG.  22 A , the device  2200  may also include a magnetic fiducial  2208  for helping to locate the separate wireless charging device or accessory. The device may also include a coil  2210  that inductively couples to an output or transmitting coil of a wireless charger. The coil  2210  may provide current to the device  2200  to charge the battery  2202  and/or power the device. The coil  2210  may include multiple wraps of a conductive wire or other conduit that is configured to produce a (charging) current in response to being placed in an inductive charging electromagnetic field produced by a separate wireless charging device or accessory. The battery  2202  may be positioned over the charging coil  2210  and attached to the housing. The areas where the battery  2202  and the charging coil  2210  overlap may be referred to as an overlap region. 
     The battery  2202  may be attached to the rear cover  2204  in various ways, including using adhesives, fasteners, mechanical interlocks, etc. The attachment of the battery  2202  to the rear cover  2204  needs to be sufficiently secure so that the battery does not become detached from the rear cover  2204  during use of the device. However, it may also be advantageous to allow the battery  2202  to be removed from the device for repairs, replacement, or the like. Further, due to components that are positioned under the battery  2202 , such as the array of magnetic elements  2206  (also referred to as magnets  2206 ) and the coil  2210 , the locations and areas that can be used to fasten the battery  2202  to the rear cover  2204  may be limited. For example, in some cases, adhesives may not be used on the magnets  2206  or the coil  2210 , as the surfaces of those components may not be suited for bonding to adhesives, and/or it may risk damaging those components. 
       FIG.  22 B  depicts an example arrangement of adhesives that may be used to attach the battery  2202  to the rear cover  2204 . In particular, first, second, and third adhesive structures  2212 ,  2214 , and  2216  may be positioned between the battery  2202  and the rear cover  2204  to adhere the battery  2202  to the rear cover  2204 . The adhesive structures  2212 ,  2214 , and  2216  may be positioned between the battery  2202  and the rear cover  2204  in coupling regions outside of the outer periphery of the coil  2210  (e.g., outside of the overlap region and between the battery  2202  and the rear cover  2204 ), the magnets  2206 , and the magnetic fiducial  2208 , such that the adhesive structures can bond to the rear cover  2204  without contacting the coil  2210 , the magnets  2206 , and the magnetic fiducial  2208 . As shown, the adhesive structures  2212 ,  2214 , and  2216  may conform to a shape of the array of magnets  2206  (e.g., they may have a curved edge that conforms to or follows the curved outer periphery of the array of magnets  2206 ) to increase the surface area covered by the adhesive structures  2212 ,  2214 , and  2216 , without contacting the magnets  2206 . 
       FIG.  22 C  is a partial cross-sectional view of the device  2200 , viewed along line  22 C- 22 C in  FIG.  22 B , illustrating an example configuration of an adhesive structure (e.g., the adhesive structure  2216 ) for use in adhering a battery to a rear cover. As noted above, it may be advantageous to adhere a battery to a rear cover (or other housing structure) such that the battery can be removed for replacement, repair, or the like, without permanently damaging the battery or the rear cover. Accordingly, a releasable adhesive, such as a stretch-release adhesive, may be used to adhere the battery to the rear cover. In some cases, however, a releasable adhesive may not bond equally well to the rear cover and the battery. In particular, the material used to form the outer surface of a battery  2202  may form a weaker bond with the releasable adhesive than the rear cover  2204 . Accordingly, a multi-layer structure may be used to produce a greater attachment force between the battery and the housing, while still facilitating the use of a releasable adhesive. For example, the multi-layer structure shown in  FIG.  22 C  includes a first adhesive  2212 , which may be a permanent or non-releasable adhesive, that adheres a polymer layer  2213  to the battery  2202 . The first adhesive  2212  may be an adhesive that forms a strong bond with both the battery  2202  (e.g., the material that forms the pouch of the battery  2202 ) and the polymer layer  2213 . The polymer layer  2213  may be any suitable material, such as a polyimide sheet. 
     The multi-layer structure may also include a releasable adhesive  2216  that is adhered to both the polymer layer  2213  and the rear cover  2204 . The releasable adhesive  2216  may form a strong bond with both the polymer layer  2213  and the rear cover  2204 . In some cases, the strength of each adhesive bond in the multi-layer structure is greater than an adhesive bond between the releasable adhesive  2216  and the battery  2202 . In this way, the benefits of the releasable adhesive are provided (e.g., the ability to non-destructively remove the battery  2202  from the rear cover  2204 ) without compromising on the ultimate bond strength between the battery  2202  and the rear cover  2204 . The adhesives  2212 ,  2216  may be films, sheets, liquids, or the like. Further, while  FIG.  22 C  illustrates an example multi-layer structure, in some cases a single adhesive layer is used to adhere the battery  2202  to the rear cover  2204 . 
       FIG.  22 D  depicts another example arrangement of adhesives that may be used to attach the battery  2202  to the rear cover  2204 . More particularly,  FIG.  22 D  depicts an example in which multiple different types of adhesives with different bonding strengths and releasability are used together. For example, first adhesive structures  2218 - 1  through  2218 - 5  are a first adhesive (e.g., stretch-release adhesives) with a first bond strength, and a second adhesive structure  2220  is a second adhesive with a second bond strength higher than the first bond strength. The first and second adhesive structures  2218 ,  2220  may be positioned between the battery  2202  and the rear cover  2204  to adhere the battery  2202  to the rear cover  2204 . While most of the first adhesives structures are positioned in areas outside of the outer periphery of the coil  2210 , the magnets  2206 , and the magnetic fiducial  2208 , at least one adhesive structure (e.g., adhesives structure  2218 - 5 ) may contact one or more magnets  2206 . As shown, adhesive structures  2218 - 1 - 2218 - 4  may conform to a shape of the array of magnets  2206  (e.g., they may have a curved edge that conforms to or follows the curved outer periphery of the array of magnets  2206 ) to increase the surface area covered by the adhesive structures. The combination of different adhesives with different adhesive strengths (and different abilities to be removed or released) provides a balance of bond strength and ease of releasability. It should be noted that while an adhesive with a higher bond strength may be more difficult to remove or release than an adhesive with a lower bond strength, a higher bond strength adhesive may still ultimately be removable, though complete removal may be more difficult (and may in some cases be aided by the use of solvents, heat, or the like). 
       FIG.  22 E  depicts another example arrangement of adhesives that may be used to attach the battery  2202  to the rear cover  2204 . More particularly,  FIG.  22 E  depicts an example in which multiple different types of adhesives with different bonding strengths and releasability are used together. For example, first adhesive structures  2222 - 1  through  2222 - 3  are a first adhesive (e.g., stretch-release adhesives) with a first bond strength, and second adhesive structures  2224 - 1  through  2224 - 4  are a second adhesive with a second bond strength higher than the first bond strength. The first and second adhesive structures  2222 ,  2224  may be positioned between the battery  2202  and the rear cover  2204  to adhere the battery  2202  to the rear cover  2204 . The arrangement of adhesives shown in  FIG.  22 E  includes an adhesive structure  2224 - 1  positioned between the magnetic fiducial  2208 , as well as an additional adhesive structure  2224 - 2  positioned in a corner region of the battery  2202 , between a top of the array of magnets  2206  and a top edge of the battery  2202 . As described above, the combination of different adhesives with different adhesive strengths (and different abilities to be removed or released) provides a balance of bond strength and ease of releasability. 
       FIG.  22 F  depicts another example arrangement of adhesives that may be used to attach the battery  2202  to the rear cover  2204 . More particularly,  FIG.  22 F  depicts an example in which a gap  2229  is defined in the array of magnets  2206  to provide an additional area for an adhesive. For example, the magnets  2206  in  FIG.  22 F  are positioned in a circular array, with a gap  2229  defined between two of the magnets  2206  at an area along a top of the array. The gap  2229  may be proximate a top edge of the battery  2202 , such that the gap provides additional area for locating an adhesive structure. This location for the gap  2229  may be particularly advantageous because it allows adhesive to be positioned in the upper left corner of the battery  2202  where there would be little or no space for adhesives if the array of magnets were continuous in that area. The adhesive structure  2226 - 3  is a unitary or single adhesive structure that defines a first lobe  2228  and a second lobe  2230 . The second lobe  2230  follows a contour or shape of the outer perimeter of the array of magnets  2206 , and is positioned at a top right region of the battery  2202 . The first lobe  2228  extends into the gap  2229  in the array of magnets  2206 . For example, a first side of the first lobe  2228  may be adjacent one of the magnets  2206 , and a second side of the first lobe  2228  may be adjacent another one of the magnets  2206 . The combination of the gap  2229  in the array and the multi-lobe adhesive structure  2226 - 3  results in adhesive being positioned along substantially an entire top edge of the battery  2202 . 
     In addition to the adhesive structure  2226 - 3 , the example in  FIG.  22 F  includes adhesive structures  2226 - 1  and  2226 - 2 , which conform to a shape of the array of magnets  2206  (e.g., they have a curved edge that conforms to or follows the curved outer periphery of the array of magnets  2206 ) to increase the surface area covered by the adhesive structures  2226  without contacting the magnets  2206 . The adhesive structures  2226 - 1  through  2226 - 3  may be any type of adhesive(s), including a releasable adhesive, a non-releasable adhesive, or the like. 
       FIGS.  22 G and  22 H  depict a portion of an electronic device, illustrating a battery retention structure that may be used to retain a battery (e.g., the battery  2202 ) in place in a device. In particular, the device includes a base plate  2232 , which may be a housing component, rear cover, frame member, or any other structural component of a device. In some cases, the base plate  2232  is attached to a rear cover of a device. The base plate  2232  may be metal, glass, polymer, or any other suitable material(s). A retention bracket  2233  (which may be or be an embodiment of the barrier wall  1740 ,  FIG.  17 A ) may be attached to the base plate  2232 . For example, mounting pads  2234  of the retention bracket  2233  may be attached to the base plate  2232  via welding, adhesives, fasteners, or the like. The retention bracket  2233  defines underpasses  2235 , also referred to as a retention slot, and retention tabs  2238  of a retention plate  2240  that is coupled to the battery  2202  (e.g., to a bottom surface of the battery  2202 ) may extend into the underpasses  2235 . As described herein, the engagement between the retention bracket  2233  and the retention tabs  2238  (and the battery  2202  more broadly) helps retain the battery  2202  in a fixed position in the device, and can help prevent or inhibit battery movement during drops or other forceful events to which a device may be subjected. 
     Each underpass  2235  may be defined between two mounting pads  2234 , and below a biasing tab  2236 . The mounting pads  2234 , biasing tabs  2236 , and the bracket wall  2237  may be portions of a unitary component, such as a single piece of metal, polymer, or the like. 
     When the retention tabs  2238  are positioned in the underpasses  2235  as shown in  FIGS.  22 G and  22 H , the retention tabs  2238  may be held captive in multiple directions, thereby retaining the battery  2202  in a target position and/or location. More particularly, the biasing tabs  2236  may prevent the retention tabs  2238 , and thus the battery  2202 , from moving in a z direction (e.g., into or out of the page, as shown in  FIG.  22 G ). Similarly, the mounting pads  2234  may prevent the retention tabs  2238 , and thus the battery  2202 , from moving in an x direction (e.g., left or right, as shown in  FIG.  22 G ). Further, the bracket wall  2237  may prevent the battery  2202  from moving in a positive y direction (e.g., upwards, as shown in  FIG.  22 G ). Accordingly, the retention bracket  2233 , along with the retention tabs  2238 , may securely retain the battery  2202  in multiple directions (and in some cases, all but one direction). 
     The particular shapes and overall configuration of the retention bracket  2233  and the retention tabs  2238  may help maintain the battery  2202  in a given position, and help reduce the likelihood of the battery  2202  shifting or otherwise changing position. For example, the biasing tabs  2236  may be biased downward against the retention tabs  2238 , thereby increasing the frictional force of the biasing tabs  2236  on the retention tabs  2238  and helping prevent unwanted movement of the battery  2202 , especially in the z and y directions of the device. Further, the retention tabs  2238  may be tapered (e.g., tapering from a first width proximate the battery  2202  to a narrower width at a distal end of the tabs). The wider portion of the tabs may contact or be close to (e.g., about 0.25 mm or less away from) the sides of the underpasses  2235 . In this way, the amount that the battery  2202  may move in the x direction (e.g., left and right, as shown in  FIG.  22 G ) is limited to the smallest distance between the retention tabs  2238  and the side of the underpasses  2235 . In the case where the sides of the retention tabs  2238  contact the sides of the underpasses  2235 , the battery  2202  may be generally fixed in the x direction. 
     The tapered shape of the retention tabs  2238  may help ensure that the retention tabs  2238  contact the sides of the underpasses  2235 . For example, the size of the underpasses  2235  may be smaller than a maximum width of the retention tabs  2238 . Thus, during assembly of the device in which the battery is translated in the positive y direction (e.g. upwards, as shown in  FIG.  22 G ), the retention tabs  2238  may be pushed into the underpasses  2235  until the sides of the retention tabs  2238  contact the sides of the underpasses  2235 . The physical interaction between the sides of the retention tabs  2238  and the sides of the underpass  2235  may therefore fix the position of the battery in both the positive y direction and in the x direction. Once the retention tabs  2238  are contacting the sides of the underpass  2235 , the battery  2202  may be secured to the housing (e.g., using adhesives as described with respect to  FIGS.  22 A- 22 F , and/or with other fasteners, brackets, or the like), thus fixing the battery in all directions. 
     In some cases, the battery  2202  itself or a portion of the retention plate  2240  limits the travel of the battery  2202  in the y direction prior to the retention tabs  2238  contacting the underpass  2235 . This may help limit the variability in the position of the batteries across devices, as different manufacturing tolerances for the retention tabs  2238  and the underpasses  2235  may result in different products having different battery positioning. 
     In electronic devices as described herein (e.g., mobile phones), various types of components or systems that are housed within the device need access to the external environment. For example, speakers, microphones, pressure sensors, cameras, etc., all need some type of access to the external environment (e.g., optical access, fluid/air access, etc.). Furthermore, in order to help prevent or limit air pressure differences between an external environment and an internal volume of a device, a venting system may be provided so that the internal volume can pressure equalize with the external environment. 
       FIGS.  23 A- 23 G  depict various examples of a module  2304  (e.g., an acoustic module) that includes at least a pressure sensor and a microphone, and optionally a venting system (also referred to as a barometric vent) all at least partially housed in an audio enclosure. The pressure sensor may be configured to detect a barometric pressure of the ambient environment, while the microphone may receive audio input, such as during a telephone call or a video recording. These components all rely on fluidic communication with the external environment in order to operate effectively. Accordingly, as shown in  FIG.  23 A , the module  2304  may be positioned within a housing  2302  of a device  2300  proximate holes  2306  (e.g., an audio port or microphone port) and  2308  (e.g., a venting port). The holes  2306 ,  2308  extend through the housing  2302  from an exterior surface of the housing  2302  to an interior surface of the housing  2302 . 
     In some cases, multiple systems of the module  2304  are fluidically coupled to the external environment via a same hole. For example, as shown in  FIG.  23 B , a microphone  2322  may be operably coupled (e.g., fluidically coupled) to a first hole  2306  (e.g., the audio port or a microphone port) via a first passage  2320  in the audio enclosure, and a pressure sensor  2312  may be operably coupled (e.g., fluidically coupled) to the first hole  2306  via a second passage  2314  in the audio enclosure. Notably, the fluid path to both the microphone  2322  and the pressure sensor  2312  share a common volume  2310  in the first hole  2306 . Separately, a barometric venting system  2316  may be fluidically coupled with the second hole  2308  (e.g., a venting port) via a third passage  2318  and configured to equalize an internal pressure within the housing with an external pressure external to the housing. 
     Because the fluid paths to both the microphone  2322  and the pressure sensor  2312  share a common partially enclosed volume  2310  (and partially due to the different lengths of the first and second passages), sound waves (e.g., air pressure waves) in the volume  2310 , first passage  2320 , and second passage  2314  may all be impacted by one another. Thus, for example, sound waves travelling to the microphone  2322  through the first passage  2320  may be affected by the presence of (and/or properties of) the second passage  2314 . In some cases, the fluidic coupling between the first and second passages  2320 ,  2314  may negatively affect the operation of the microphone  2322 , such as by attenuating certain frequencies of sound that would otherwise reach the microphone  2322 . Such attenuation or other effects may be due, for example, to a resonance or other phenomena caused by the first and second passages  2320 ,  2314  being fluidically coupled at the common volume  2310 . Accordingly, it may be advantageous to reduce the extent and/or effect of the fluidic coupling between the first and second passages  2320 ,  2314 , thereby improving the overall function of the microphone  2322  and/or the pressure sensor  2312 . 
     One technique for reducing the extent and/or effect of the fluidic coupling between the first and second passages  2320 ,  2314  includes providing a baffle somewhere between the first and second passages  2320 ,  2314 .  FIG.  23 C  depicts an example in which a baffle  2324  (which may be an acoustic mesh) is positioned between two compliant gasket layers  2332 ,  2334  and covers an opening to the second passage  2314  (e.g., it is between the end of the second passage  2314  and the audio port). The baffle  2324 , or acoustic mesh, allows air to pass through it so that the pressure sensor  2312  (or other sensor or component) is still in fluidic communication with the external environment via the second passage  2314 , while also providing an acoustic or fluidic dampening between the first passage  2320  and the second passage  2314 . In this way, the negative effect of the second passage  2314  on sound waves passing through the first passage  2320  may be reduced or eliminated. In some cases, no baffle or acoustic mesh is positioned over the opening to the first passage  2320 . 
     The baffle  2324  may be formed from any suitable material or structure, such as an open-cell foam, metal mesh, air-permeable polymer mesh (e.g., a polyethylene terephthalate mesh), fabric, perforated or semi-permeable polymer film, or the like. The baffle  2324  may be captured between two gaskets  2332 ,  2334 . The baffle  2324  may have an acoustic impedance property or characteristic that reduces the impact of the second passage  2314  on pressure waves in the first passage  2320 , while also allowing air to pass into the second passage  2314  without significantly impacting the operation of the pressure sensor  2312 . For example, the baffle  2324  may have an acoustic impedance of between about 100 and about 700 Rayl. In some cases, the baffle  2324  has an acoustic impedance of between about 150 Rayl and about 300 Rayl. The baffle  2324  may have a thickness between about 40 microns and about 100 microns. 
     The gaskets  2332 ,  2334  may hold the baffle  2324  in place over the opening of the second passage  2314 , and also provide a seal between the module  2304  and the housing  2302 . The gaskets  2332 ,  2334  may each define a distinct hole  2336 ,  2338 , respectively, corresponding to each of the first, second, and third passages  2320 ,  2314 ,  2318  of the module  2304 . The holes  2336 - 1  and  2338 - 1  communicate with the microphone, and may be referred to as acoustic holes, and the holes  2336 - 2  and  2338 - 2  communicate with the pressure sensor and may be referred to as pressure holes Both the hole  2336 - 1  and the hole  2336 - 2  may open to the same partially enclosed volume of the audio port  2306  in the housing  2302 , and thus serve as the openings where the passages  2320 ,  2314  ultimately open into the common volume  2310 . 
     The gaskets  2332 ,  2334  may be or may be formed from adhesive films, such as a PSA film, and may adhesively bond to the housing  2302 , the module  2304 , the baffle  2324 , and/or each other. In some cases, the gaskets  2332 ,  2334  are formed from or include compliant materials, such as a foam, elastomer, polymer, or the like. The gaskets  2332 ,  2334  may be compressed between (and optionally deformed by) the module  2304  and the housing  2302 . 
       FIG.  23 D  depicts another example module  2340  (e.g., acoustic module) that includes at least a pressure sensor  2342  and a microphone  2349 , and optionally a barometric vent (similar to or the same as the barometric vent shown in  FIG.  23 B ). The microphone  2349  and pressure sensor  2342  are both fluidically coupled to a common volume within the module  2340 , as well as the common volume  2310  defined by the housing  2302  (when integrated into a device as shown in  FIGS.  23 A- 23 B ). In particular, the module  2340  defines a first passage  2348  that extends from the opening  2341  in the module  2340  to a second passage  2344 . The microphone  2349  (or an opening that fluidically couples to a microphone) is positioned in the first passage  2348 , and the second passage  2344  fluidically couples the first passage  2348  to the pressure sensor  2342 . A baffle  2346  is positioned between the first passage  2348  and the second passage  2344 . 
     The baffle  2346  may be formed from any suitable material or structure, such as an open-cell foam, metal mesh, polymer mesh (e.g., a polyethylene terephthalate mesh), fabric, perforated or semi-permeable polymer film, or the like. The baffle  2346  may include or be incorporated with adhesives (e.g., an adhesive gasket) to secure the baffle  2346  in place between the first and second passages  2348 ,  2344 . The baffle  2346  may have an acoustic impedance property or characteristic that reduces the impact of the second passage  2344  on pressure waves in the first passage  2348 , while also allowing air to pass into the second passage  2344  without significantly impacting the operation of the pressure sensor  2342 . For example, the baffle  2346  may have an acoustic impedance of between about 100 and about 700 Rayl. In some cases, the baffle  2346  has an acoustic impedance of between about 150 Rayl and about 300 Rayl. The baffle  2346  may have a thickness between about 40 microns and about 100 microns. 
       FIG.  23 E  depicts another example module  2350  (e.g., acoustic module) that includes at least a pressure sensor and a microphone, and optionally a barometric vent (similar to or the same as the barometric vent shown in  FIG.  23 B ). The microphone and pressure sensor are both fluidically coupled to the common volume  2310  defined by the housing  2302  when integrated into a device as shown in  FIGS.  23 A- 23 B . The module  2350  defines a first passage  2354  that communicates with the common volume  2310  and is fluidically coupled to a microphone, and a second passage  2356  that communicates with the common volume  2310  and is fluidically coupled to a pressure sensor. The module  2350  also defines a third passage  2352  that is fluidically coupled to a barometric vent. 
     The module  2350  also defines a recess  2355  in a mounting surface of the module  2350 . The openings to both of the first and second passages  2354 ,  2356  are within the recess. A gasket  2357  may be positioned in the recess  2355 . The gasket  2357  may have a thickness that is equal to or greater than the recess  2355  such that the gasket  2357  contacts the surface of the housing  2302  when the module  2350  is assembled into a device, and optionally is compressed between the module  2350  and the housing  2302 . The gasket  2357  may define a first hole  2358 , which corresponds to and/or is aligned with the opening to the first passage  2354 , and a second hole  2359 , which corresponds to and/or is aligned with the opening to the second passage  2356 . 
     The gasket  2357  may include a baffle  2351  (e.g., an acoustic mesh) positioned in the second hole  2359  of the gasket  2357 . When the gasket  2357  is positioned in the recess  2355  and captured between the module  2350  and the housing  2302 , the baffle  2351  provides an acoustic or fluidic dampening between the first passage  2354  and the second passage  2356 . More particularly, because the first passage  2354  and the second passage  2356  (through the baffle  2351 ) both open directly into the common volume  2310 , the baffle  2351  forms an air-permeable, acoustic dampening barrier between the first and second passages  2354 ,  2356 . 
     The baffle  2351  may be formed from any suitable material or structure, such as an open-cell foam, metal mesh, polymer mesh (e.g., a polyethylene terephthalate mesh), fabric, perforated or semi-permeable polymer film, or the like. The baffle  2351  may be attached (e.g., adhered) to a surface of the gasket  2357 , or it may be positioned between layers of the gasket  2357  (e.g., where the gasket  2357  is formed of multiple layers, such as two layers of PSA film). 
     The baffle  2351  may have an acoustic impedance property or characteristic that reduces the impact of the second passage  2356  on pressure waves in the first passage  2354 , while also allowing air to pass into the second passage  2356  without significantly impacting the operation of the pressure sensor. For example, the baffle  2351  may have an acoustic impedance of between about 100 and about 700 Rayl. In some cases, the baffle  2351  has an acoustic impedance of between about 150 Rayl and about 300 Rayl. The baffle  2351  may have a thickness between about 40 microns and about 100 microns. 
       FIG.  23 F  depicts another example module  2360  that includes at least a pressure sensor and a microphone, and optionally a barometric vent (similar to or the same as the barometric vent shown in  FIG.  23 B ). The microphone and pressure sensor are both fluidically coupled to the common volume  2310  defined by the housing  2302  when integrated into a device as shown in  FIGS.  23 A- 23 B . The module  2360  defines a first passage  2364  that communicates with the common volume  2310  and is fluidically coupled to a microphone, and a second passage  2362  that communicates with the common volume  2310  and is fluidically coupled to a pressure sensor. The module  2360  also defines a third passage  2361  that is fluidically coupled to a barometric vent. 
     In the example of  FIG.  23 F , a baffle  2369  (e.g., an acoustic mesh) is integrated with a first gasket  2368 . More particularly, the first gasket  2368  may define a first hole  2367 , which corresponds to and/or is aligned with the opening to the first passage  2364 , a second hole  2366 , which corresponds to and/or is aligned with the opening to the second passage  2362 , and a third hole  2365 , which corresponds to and/or is aligned with the opening to the third passage  2361 . The baffle  2369  may be positioned in the second hole  2366  of the first gasket  2368 . When the first gasket  2368  is captured between the module  2360  and the housing  2302 , the baffle  2369  provides an acoustic or fluidic dampening between the first passage  2364  and the second passage  2362 . More particularly, because the first passage  2364  and the second passage  2362  (through the baffle  2369 ) both open directly into the common volume  2310 , the baffle  2369  forms an air-permeable, acoustic dampening barrier between the first and second passages  2364 ,  2362 . 
     The baffle  2369  may be formed from any suitable material or structure, such as an open-cell foam, metal mesh, polymer mesh (e.g., a polyethylene terephthalate mesh), fabric, perforated or semi-permeable polymer film, or the like. The baffle  2369  may be attached (e.g., adhered) to a surface of the first gasket  2368 , or it may be positioned between layers of the first gasket  2368  (e.g., where the first gasket  2368  is formed of multiple layers, such as two layers of PSA film). 
     The baffle  2369  may have an acoustic impedance property or characteristic that reduces the impact of the second passage  2362  on pressure waves in the first passage  2364 , while also allowing air to pass into the second passage  2362  without significantly impacting the operation of the pressure sensor. For example, the baffle  2369  may have an acoustic impedance of between about 100 and about 700 Rayl. In some cases, the baffle  2369  has an acoustic impedance of between about 150 Rayl and about 300 Rayl. The baffle  2369  may have a thickness between about 40 microns and about 100 microns. 
     In some cases, a second gasket  2363  may be provided around the openings to the first, second, and third passages  2364 ,  2362 ,  2361  of the module  2360 . The second gasket  2363  may be a compliant material, such as rubber, elastomer, foam, or the like, and may be compressed between or otherwise make contact with the module  2360  and the first gasket  2368 . In some cases, the first and second gaskets are formed of different materials and/or have different hardnesses. The second gasket  2363  and the housing of the module  2360  may be formed together, such as via a multi-shot molding process in which the housing and the second gasket  2363  are formed in the same mold to produce a unitary component with different materials. 
       FIG.  23 G  depicts another example module  2370  (e.g., acoustic module) that includes at least a pressure sensor and a microphone, and optionally a barometric vent (similar to or the same as the barometric vent shown in  FIG.  23 B ). The microphone and pressure sensor are both fluidically coupled to the common volume  2310  defined by the housing  2302  when integrated into a device as shown in  FIGS.  23 A- 23 B . The module  2370  defines a first passage  2374  that communicates with the common volume  2310  and is fluidically coupled to a microphone, and a second passage  2372  that communicates with the common volume  2310  and is fluidically coupled to a pressure sensor. The module  2370  also defines a third passage  2371  that is fluidically coupled to a barometric vent. 
     The module  2370  also defines a recess  2373  in a mounting surface of the module  2370 . The openings to the second passage  2372  is within the recess  2373 , while the opening to the first passage  2374  is not within the recess. A gasket  2375  may be positioned in the recess  2373 . The gasket  2375  may have a thickness that is equal to or greater than the recess  2373  such that the gasket  2375  contacts the surface of the housing  2302  when the module  2370  is assembled into a device, and optionally is compressed between the module  2370  and the housing  2302 . 
     The gasket  2375  may include a baffle  2376  (e.g., an acoustic mesh) positioned in a hole defined in the gasket  2375 . When the gasket  2375  is positioned in the recess  2373  and captured between the module  2370  and the housing  2302 , the baffle  2376  provides an acoustic or fluidic dampening between the first passage  2374  and the second passage  2372 . More particularly, because the first passage  2374  and the second passage  2372  (through the baffle  2376 ) both open directly into the common volume  2310 , the baffle  2376  forms an air-permeable, acoustic dampening barrier between the first and second passages  2374 ,  2372 . 
     The baffle  2376  may be formed from any suitable material or structure, such as an open-cell foam, metal mesh, polymer mesh (e.g., a polyethylene terephthalate mesh), fabric, perforated or semi-permeable polymer film, or the like. The baffle  2376  may be attached (e.g., adhered) to a surface of the gasket  2375 , or it may be positioned between layers of the gasket  2375  (e.g., where the gasket  2375  is formed of multiple layers, such as two layers of PSA film). 
     The baffle  2376  may have an acoustic impedance property or characteristic that reduces the impact of the second passage  2372  on pressure waves in the first passage  2374 , while also allowing air to pass into the second passage  2372  without significantly impacting the operation of the pressure sensor. For example, the baffle  2376  may have an acoustic impedance of between about 100 and about 700 Rayl. In some cases, the baffle  2376  has an acoustic impedance of between about 150 Rayl and about 300 Rayl. The baffle  2376  may have a thickness between about 40 microns and about 100 microns. 
     As noted above, modules for use in electronic devices may include barometric vents. The barometric vents may define a passage between the internal volume of the device and the exterior environment to allow pressure equalization between the internal volume and the exterior environment. In some cases, the barometric vents include an air-permeable, waterproof component (e.g., an air-permeable, waterproof polymer membrane) to allow air to pass between the internal volume and the exterior environment (to allow for pressure equalization), while inhibiting or limiting passage of water or other liquids or contaminants. 
       FIG.  24    depicts an example schematic diagram of an electronic device  2400 . The electronic device  2400  may be an embodiment of or otherwise represent the device  100  (or other devices described herein, such as the devices  100 ,  140 ,  200 ,  300 ,  400 ,  900 ,  1300 ,  1400 ,  1700 ,  2200 , or the like). The device  2400  includes one or more processing units  2401  that are configured to access a memory  2402  having instructions stored thereon. The instructions or computer programs may be configured to perform one or more of the operations or functions described with respect to the electronic devices described herein. For example, the instructions may be configured to control or coordinate the operation of one or more displays  2408 , one or more touch sensors  2403 , one or more force sensors  2405 , one or more communication channels  2404 , one or more audio input systems  2409 , one or more audio output systems  2410 , one or more positioning systems  2411 , one or more sensors  2412 , and/or one or more haptic feedback devices  2406 . 
     The processing units  2401  of  FIG.  24    may be implemented as any electronic device capable of processing, receiving, or transmitting data or instructions. For example, the processing units  2401  may include one or more of: a microprocessor, a central processing unit (CPU), an application-specific integrated circuit (ASIC), a digital signal processor (DSP), or combinations of such devices. As described herein, the term “processor” is meant to encompass a single processor or processing unit, multiple processors, multiple processing units, or other suitably configured computing element or elements. The processing units  2401  may be coupled to a logic board, such as the logic board  2100  of  FIG.  21 A . 
     The memory  2402  can store electronic data that can be used by the device  2400 . For example, a memory can store electrical data or content such as, for example, audio and video files, images, documents and applications, device settings and user preferences, programs, instructions, timing and control signals or data for the various modules, data structures or databases, and so on. The memory  2402  can be configured as any type of memory. By way of example only, the memory can be implemented as random access memory, read-only memory, Flash memory, removable memory, or other types of storage elements, or combinations of such devices. The memory  2402  may be coupled to a logic board, such as the logic board  2100  of  FIG.  21 A . 
     The touch sensors  2403  may detect various types of touch-based inputs and generate signals or data that are able to be accessed using processor instructions. The touch sensors  2403  may use any suitable components and may rely on any suitable phenomena to detect physical inputs. For example, the touch sensors  2403  may be capacitive touch sensors, resistive touch sensors, acoustic wave sensors, or the like. The touch sensors  2403  may include any suitable components for detecting touch-based inputs and generating signals or data that are able to be accessed using processor instructions, including electrodes (e.g., electrode layers), physical components (e.g., substrates, spacing layers, structural supports, compressible elements, etc.), processors, circuitry, firmware, and the like. The touch sensors  2403  may be integrated with or otherwise configured to detect touch inputs applied to any portion of the device  2400 . For example, the touch sensors  2403  may be configured to detect touch inputs applied to any portion of the device  2400  that includes a display (and may be integrated with a display). The touch sensors  2403  may operate in conjunction with the force sensors  2405  to generate signals or data in response to touch inputs. A touch sensor or force sensor that is positioned over a display surface or otherwise integrated with a display may be referred to herein as a touch-sensitive display, force-sensitive display, or touchscreen. 
     The force sensors  2405  may detect various types of force-based inputs and generate signals or data that are able to be accessed using processor instructions. The force sensors  2405  may use any suitable components and may rely on any suitable phenomena to detect physical inputs. For example, the force sensors  2405  may be strain-based sensors, piezoelectric-based sensors, piezoresistive-based sensors, capacitive sensors, resistive sensors, or the like. The force sensors  2405  may include any suitable components for detecting force-based inputs and generating signals or data that are able to be accessed using processor instructions, including electrodes (e.g., electrode layers), physical components (e.g., substrates, spacing layers, structural supports, compressible elements, etc.), processors, circuitry, firmware, and the like. The force sensors  2405  may be used in conjunction with various input mechanisms to detect various types of inputs. For example, the force sensors  2405  may be used to detect presses or other force inputs that satisfy a force threshold (which may represent a more forceful input than is typical for a standard “touch” input). Like the touch sensors  2403 , the force sensors  2405  may be integrated with or otherwise configured to detect force inputs applied to any portion of the device  2400 . For example, the force sensors  2405  may be configured to detect force inputs applied to any portion of the device  2400  that includes a display (and may be integrated with a display). The force sensors  2405  may operate in conjunction with the touch sensors  2403  to generate signals or data in response to touch- and/or force-based inputs. 
     The device  2400  may also include one or more haptic devices  2406  (e.g., the haptic actuator  222 ,  322  of  FIGS.  2 - 3   ). The haptic device  2406  may include one or more of a variety of haptic technologies such as, but not necessarily limited to, rotational haptic devices, linear actuators, piezoelectric devices, vibration elements, and so on. In general, the haptic device  2406  may be configured to provide punctuated and distinct feedback to a user of the device. More particularly, the haptic device  2406  may be adapted to produce a knock or tap sensation and/or a vibration sensation. Such haptic outputs may be provided in response to detection of touch and/or force inputs, and may be imparted to a user through the exterior surface of the device  2400  (e.g., via a glass or other surface that acts as a touch- and/or force-sensitive display or surface). 
     The one or more communication channels  2404  may include one or more wireless interface(s) that are adapted to provide communication between the processing unit(s)  2401  and an external device. The one or more communication channels  2404  may include antennas (e.g., antennas that include or use the housing members of the housing  104  as radiating members), communications circuitry, firmware, software, or any other components or systems that facilitate wireless communications with other devices. In general, the one or more communication channels  2404  may be configured to transmit and receive data and/or signals that may be interpreted by instructions executed on the processing units  2401 . In some cases, the external device is part of an external communication network that is configured to exchange data with wireless devices. Generally, the wireless interface may communicate via, without limitation, radio frequency, optical, acoustic, and/or magnetic signals and may be configured to operate over a wireless interface or protocol. Example wireless interfaces include radio frequency cellular interfaces (e.g., 2G, 3G, 4G, 4G long-term evolution (LTE), 5G, GSM, CDMA, or the like), fiber optic interfaces, acoustic interfaces, Bluetooth interfaces, infrared interfaces, USB interfaces, Wi-Fi interfaces, TCP/IP interfaces, network communications interfaces, or any conventional communication interfaces. The one or more communications channels  2404  may also include ultra-wideband interfaces, which may include any appropriate communications circuitry, instructions, and number and position of suitable UWB antennas. 
     As shown in  FIG.  24   , the device  2400  may include a battery  2407  that is used to store and provide power to the other components of the device  2400 . The battery  2407  may be a rechargeable power supply that is configured to provide power to the device  2400 . The battery  2407  may be coupled to charging systems (e.g., wired and/or wireless charging systems) and/or other circuitry to control the electrical power provided to the battery  2407  and to control the electrical power provided from the battery  2407  to the device  2400 . 
     The device  2400  may also include one or more displays  2408  configured to display graphical outputs. The displays  2408  may use any suitable display technology, including liquid crystal displays (LCD), organic light emitting diodes (OLED), active-matrix organic light-emitting diode displays (AMOLED), or the like. The displays  2408  may display graphical user interfaces, images, icons, or any other suitable graphical outputs. The display  2408  may correspond to a display  103 ,  203 ,  303 ,  610 . 
     The device  2400  may also provide audio input functionality via one or more audio input systems  2409 . The audio input systems  2409  may include microphones, transducers, or other devices that capture sound for voice calls, video calls, audio recordings, video recordings, voice commands, and the like. 
     The device  2400  may also provide audio output functionality via one or more audio output systems (e.g., speakers)  2410 , such as the speaker systems and/or modules  224 ,  250 ,  324 ,  350 ,  620 . The audio output systems  2410  may produce sound from voice calls, video calls, streaming or local audio content, streaming or local video content, or the like. 
     The device  2400  may also include a positioning system  2411 . The positioning system  2411  may be configured to determine the location of the device  2400 . For example, the positioning system  2411  may include magnetometers, gyroscopes, accelerometers, optical sensors, cameras, global positioning system (GPS) receivers, inertial positioning systems, or the like. The positioning system  2411  may be used to determine spatial parameters of the device  2400 , such as the location of the device  2400  (e.g., geographical coordinates of the device), measurements or estimates of physical movement of the device  2400 , an orientation of the device  2400 , or the like. 
     The device  2400  may also include one or more additional sensors  2412  to receive inputs (e.g., from a user or another computer, device, system, network, etc.) or to detect any suitable property or parameter of the device, the environment surrounding the device, people, or things interacting with the device (or nearby the device), or the like. For example, a device may include temperature sensors, biometric sensors (e.g., fingerprint sensors, photoplethysmographs, blood-oxygen sensors, blood sugar sensors, or the like), eye-tracking sensors, retinal scanners, humidity sensors, buttons, switches, lid-closure sensors, or the like. 
     To the extent that multiple functionalities, operations, and structures described with reference to  FIG.  24    are disclosed as being part of, incorporated into, or performed by the device  2400 , it should be understood that various embodiments may omit any or all such described functionalities, operations, and structures. Thus, different embodiments of the device  2400  may have some, none, or all of the various capabilities, apparatuses, physical features, modes, and operating parameters discussed herein. Further, the systems included in the device  2400  are not exclusive, and the device  2400  may include alternative or additional systems, components, modules, programs, instructions, or the like, that may be necessary or useful to perform the functions described herein. 
     As described above, one aspect of the present technology is the gathering and use of data available from various sources to improve the usefulness and functionality of devices such as mobile phones. The present disclosure contemplates that in some instances, this gathered data may include personal information data that uniquely identifies or can be used to contact or locate a specific person. Such personal information data can include demographic data, location-based data, telephone numbers, email addresses, twitter ID&#39;s, home addresses, data or records relating to a user&#39;s health or level of fitness (e.g., vital signs measurements, medication information, exercise information), date of birth, or any other identifying or personal information. 
     The present disclosure recognizes that the use of such personal information data, in the present technology, can be used to the benefit of users. For example, the personal information data can be used to locate devices, deliver targeted content that is of greater interest to the user, or the like. Further, other uses for personal information data that benefit the user are also contemplated by the present disclosure. For instance, health and fitness data may be used to provide insights into a user&#39;s general wellness, or may be used as positive feedback to individuals using technology to pursue wellness goals. 
     The present disclosure contemplates that the entities responsible for the collection, analysis, disclosure, transfer, storage, or other use of such personal information data will comply with well-established privacy policies and/or privacy practices. In particular, such entities should implement and consistently use privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining personal information data private and secure. Such policies should be easily accessible by users, and should be updated as the collection and/or use of data changes. Personal information from users should be collected for legitimate and reasonable uses of the entity and not shared or sold outside of those legitimate uses. Further, such collection/sharing should occur after receiving the informed consent of the users. Additionally, such entities should consider taking any needed steps for safeguarding and securing access to such personal information data and ensuring that others with access to the personal information data adhere to their privacy policies and procedures. Further, such entities can subject themselves to evaluation by third parties to certify their adherence to widely accepted privacy policies and practices. In addition, policies and practices should be adapted for the particular types of personal information data being collected and/or accessed and adapted to applicable laws and standards, including jurisdiction-specific considerations. For instance, in the US, collection of or access to certain health data may be governed by federal and/or state laws, such as the Health Insurance Portability and Accountability Act (HIPAA); whereas health data in other countries may be subject to other regulations and policies and should be handled accordingly. Hence different privacy practices should be maintained for different personal data types in each country. 
     Despite the foregoing, the present disclosure also contemplates embodiments in which users selectively block the use of, or access to, personal information data. That is, the present disclosure contemplates that hardware and/or software elements can be provided to prevent or block access to such personal information data. For example, in the case of advertisement delivery services, the present technology can be configured to allow users to select to “opt in” or “opt out” of participation in the collection of personal information data during registration for services or anytime thereafter. In addition to providing “opt in” and “opt out” options, the present disclosure contemplates providing notifications relating to the access or use of personal information. For instance, a user may be notified upon downloading an app that their personal information data will be accessed and then reminded again just before personal information data is accessed by the app. 
     Moreover, it is the intent of the present disclosure that personal information data should be managed and handled in a way to minimize risks of unintentional or unauthorized access or use. Risk can be minimized by limiting the collection of data and deleting data once it is no longer needed. In addition, and when applicable, including in certain health related applications, data de-identification can be used to protect a user&#39;s privacy. De-identification may be facilitated, when appropriate, by removing specific identifiers (e.g., date of birth, etc.), controlling the amount or specificity of data stored (e.g., collecting location data at a city level rather than at an address level), controlling how data is stored (e.g., aggregating data across users), and/or other methods. 
     Therefore, although the present disclosure broadly covers use of personal information data to implement one or more various disclosed embodiments, the present disclosure also contemplates that the various embodiments can also be implemented without the need for accessing such personal information data. That is, the various embodiments of the present technology are not rendered inoperable due to the lack of all or a portion of such personal information data. For example, content can be selected and delivered to users by inferring preferences based on non-personal information data or a bare minimum amount of personal information, such as the content being requested by the device associated with a user, other non-personal information available to the content delivery services, or publicly available information. 
     The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of the specific embodiments described herein are presented for purposes of illustration and description. They are not targeted to be exhaustive or to limit the embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings. Also, when used herein to refer to positions of components, the terms above, below, over, under, left, or right (or other similar relative position terms), do not necessarily refer to an absolute position relative to an external reference, but instead refer to the relative position of components within the figure being referred to. Similarly, horizontal and vertical orientations may be understood as relative to the orientation of the components within the figure being referred to, unless an absolute horizontal or vertical orientation is indicated. 
     Features, structures, configurations, components, techniques, etc. shown or described with respect to any given figure (or otherwise described in the application) may be used with features, structures, configurations, components, techniques, etc. described with respect to other figures. For example, any given figure of the instant application should not be understood to be limited to only those features, structures, configurations, components, techniques, etc. shown in that particular figure. Similarly, features, structures, configurations, components, techniques, etc. shown only in different figures may be used or implemented together. Further, features, structures, configurations, components, techniques, etc. that are shown or described together may be implemented separately and/or combined with other features, structures, configurations, components, techniques, etc. from other figures or portions of the instant specification. Further, for ease of illustration and explanation, figures of the instant application may depict certain components and/or sub-assemblies in isolation from other components and/or sub-assemblies of an electronic device, though it will be understood that components and sub-assemblies that are illustrated in isolation may in some cases be considered different portions of a single electronic device (e.g., a single embodiment that includes multiple of the illustrated components and/or sub-assemblies).

Metadata:
Filing Date: 20210910
Publication Date: 20231205
Grant Date: 20231205
Priority Date: 20210302
Inventors: NEEVEL, JASON B.
TOMASETTA, CHRISTOPHER S.
LEE, JONATHAN M.
PEASE, Ekaterina
MERZ, NICHOLAS
Jarvis, Daniel
WITTENBERG, MICHAEL B.
OSTDIEK, JARED P.
PHOUTHAVONG, RASAMY
PAKULA, DAVID A.
KOCH, RICHARD H.
RAMMAH, MARWAN
SPRAGGS, IAN A.
BURKE, Laura M.
Assignee: APPLE INC
CPC Classifications: [{"code": "G01J1/4204", "inventive": true, "first": true, "tree": "[]"}, {"code": "G01J1/0219", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01J1/0233", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01J1/0411", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01J1/0474", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01J1/0252", "inventive": false, "first": false, "tree": "[]"}, {"code": "G01J2001/0257", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04M1/026", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04M1/0202", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04M1/0266", "inventive": true, "first": true, "tree": "[]"}, {"code": "G01J1/4204", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04M1/18", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/026", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/0266", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/21", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/22", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/0264", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/0272", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/72454", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/026", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M2250/12", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2360/144", "inventive": false, "first": false, "tree": "[]"}, {"code": "H10K59/60", "inventive": false, "first": false, "tree": "[]"}, {"code": "G01J1/0219", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01J1/0233", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01J1/0252", "inventive": false, "first": false, "tree": "[]"}, {"code": "G01J1/0411", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01J1/0474", "inventive": true, "first": false, "tree": "[]"}, {"code": "G01J2001/0257", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04M1/026", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 80448829