PORTABLE ELECTRONIC DEVICE

Abstract

An electronic device may include an input structure, the input structure including a sensing element and a touch-sensitive element coupled to the sensing element. The input structure may further include a beam structure at least partially located within the enclosure, the beam structure configured to deflect as a result of the force input, a strain sensing element coupled to the beam structure, and a dome switch configured to collapse in response to the force input satisfying a first force threshold.The electronic device may determine a location of the force input on the input structure, cause the electronic device to perform a first operation in response to determining that the force input meets a second force threshold that is less than the first force threshold, and cause the electronic device to perform a second operation, different from the first operation, in response to detecting the breakdown of the tie breaker.

Description

CROSS REFERENCE TO RELATED APPLICATION. APPLICATIONSThe present application is a non-provisional patent application of U.S. Provisional Patent Application No. 63 / 623,200, filed January 19, 2024, entitled "Handheld Electronic Device", and U.S. Provisional Patent Application No. 63 / 685,221, filed August 20, 2024, entitled "Handheld Electronic Device", the disclosures of which are hereby incorporated by reference in their entirety.REGIONThe subject matter of this disclosure relates generally to portable electronic devices, and more particularly to mobile devices.BACKGROUNDModern consumer-oriented electronic devices have numerous forms and uses, as well as numerous functions. For example, smart phones provide users with various opportunities for interaction with other people beyond the telephony communication. Such devices may include numerous systems that facilitate such interactions. For example, a smartphone may include a touch-sensitive display for providing graphical output and accepting touch inputs, wireless communication systems for connection to other devices for transmitting and receiving voice and data content, cameras for capturing photographs and videos, and so forth. However, the integration of these subsystems into a compact and reliable product that can withstand daily use presents a number of technical challenges. The systems and techniques described herein can overcome many of these challenges while providing an apparatus that offers a wide range of functions.SUMMARYAn electronic device may include a case including a front cover defining a front side of the electronic device and a housing component connected to the front cover and defining a side of the electronic device. The electronic device may further include an input structure positioned along the side of the electronic device and configured to receive a force input, the input structure including a button and a touch sensitive element coupled to the button. The input structure may further include a beam structure at least partially located within the shell, the beam structure configured to deflect as a result of the force input, a strain gauge coupled to the beam structure, and a dome switch configured to collapse in response to the force input satisfying a first force threshold. The electronic device may further include a processing system operatively coupled to the touch-sensitive element, the strain-sensitive element, and the dome switch and configured to determine a location of the force input on the input structure based at least in part on a first signal from the touch-sensitive element, cause the electronic device to perform a first operation in response to detecting, based at least in part on a second signal from the strain-sensitive element, that the force input satisfies a second force threshold that is less than the first force threshold, and cause the electronic device to perform a second operation different than the first operation in response to detecting the collapse of the dome switch. The touch-sensitive element may include a linear array of touch-sensitive pixels.The electronic device may further include a haptic actuation system. The processing system may be configured to cause the haptic actuation system to generate a first haptic output when the force input is detected to meet the second force threshold, and the dome switch may generate a second haptic output when collapsed in response to the force input meeting the first force threshold.The electronic device may further include a camera and a display configured to display graphical user interfaces, and the second operation may further include causing the display to transition to a graphical user interface associated with an image capture function. The processing system may be further configured to capture an image in response to detecting the collapse of the dome switch.The processing system may be further configured to detect gesture input applied to the input structure based at least in part on a third signal from the touch-sensitive element, and to cause the electronic device to perform a third operation different from the first operation and the second operation in response to the detection of the gesture input. The third operation may include a zooming operation for an image pickup function. The gesture input may be a first gesture input corresponding to a swipe in a first direction, the zoom operation may include a zoom-in operation, and the processing system may be further configured to detect a second gesture input corresponding to a swipe in a second direction opposite the first direction and perform a zoom-out operation in response to the detection of the second gesture input.A portable electronic device may include a touch screen display device, a battery, a case enclosing the touch screen display device and the battery, the case including a front cover positioned over the touch screen display device and defining a front outer surface of the case, and a housing component connected to the front cover and defining an opening along an outer surface of the case. The portable electronic device may further include an input key system comprising a beam structure located at least partially within the shell and defining a compliant segment, a strain gauge coupled to the compliant segment, a switching element coupled to the beam structure, a key element positioned at least partially within the opening configured to apply a force to the switching element as a result of a force input applied to the key element, and a touch gauge coupled to the key element. The portable electronic device may further include a processing system configured to cause the portable electronic device to perform a first operation in response to detecting, based at least in part on a first signal from the strain sensitive element, that the force input satisfies a force threshold, cause the portable electronic device to perform a second operation different from the first operation in response to detecting, based at least in part on a second signal from the touch sensitive element, a touch input applied to the input key system, and cause the portable electronic device to perform a third operation different from the first operation and the second operation in response to detecting the operation of the switching element. The key element may have an elongated shape defining a longitudinal axis, and the touch-sensitive element may include a linear array of touch-sensitive pixels arranged along the longitudinal axis.The key element may define a chassis portion and a hollow post extending into a hole defined by the housing component, and the input key system may further include a flexible circuit element coupled to the touch-sensitive element and extending through the hollow post, the flexible circuit element operatively coupling the touch-sensitive element to the processing system. The portable electronic device may further include a potting material that at least partially fills the hollow post and encapsulates at least a portion of the flexible circuit element.The touch input may correspond to a swiping gesture along an input surface of the input key system, the swiping gesture having a swiping direction. The second operation may correspond to a zooming operation of an image capturing function, and a direction of the zooming operation may correspond to the swiping direction.The wearable electronic device may further include a haptic actuation system, and the processing system may be configured to cause the haptic actuation system to produce a first haptic output in response to detecting that the force input satisfies the force threshold, and to cause the haptic actuation system to produce a second haptic output in response to a notification event.A mobile phone may include a housing component, a front cover connected to the housing component, a display positioned below the front cover, and an input key system positioned along a side of the housing component. The input button system may be responsive to a first force input satisfying a first force threshold, a second force input satisfying a second force threshold different than the first force threshold, and a touch input. The input key system may include a key element, a touch sensitive element connected to the key element, a beam structure configured to be deflected by the key element in response to the first force input and the second force input, a strain sensitive element connected to the beam structure, and a switching element configured to be actuated in response to the second force input satisfying the second force threshold. The mobile phone may further include a processing system operatively coupled to the touch sensing element, the strain sensing element, and the switching element and configured to cause the mobile phone to perform a first operation in response to sensing the touch input with the touch sensing element, cause the mobile phone to perform a second operation in response to determining with the strain sensing element that the second force input satisfies the first force threshold, and cause the mobile phone to perform a third operation in response to sensing an actuation of the switching element.The input key system may further include an actuation structure coupled to the key element, wherein the switching element may be coupled to the beam structure and positioned between the beam structure and the actuation structure, and the actuation structure applies an actuation force to the switching element in response to the second force input.The support structure may define a compliant segment and a support segment separated from the compliant segment by a gap, the switching element may be coupled to the compliant segment, and the strain sensor element may be coupled to the compliant segment. The sensing element may define a housing portion, a first post extending from the housing portion and through a first hole formed through the housing component, and a second post extending from the housing portion and through a second hole formed through the housing component, and the input key system may further include a stabilizing bar connected to the first post and the second post and received between the support segment of the beam structure and the housing component. The first post may be a hollow post, and the input key system may further include a circuit element conductively connected to the touch-sensitive element and extending through the hollow post, the circuit element operatively connecting the touch-sensitive element to the processing system. The input key system may further include a cover connected to the key element and positioned over the touch element, and a potting material at least partially encapsulating the touch element and the circuit element and at least partially filling the hollow post.A mobile phone may include a display, wireless communication circuitry, a battery, and a housing enclosing the display, the wireless communication circuitry, and the battery. The enclosure may include a front cover defining a front outer surface of the mobile phone, a rear cover defining a rear outer surface of the mobile phone, a housing segment connected to the front cover and the rear cover, and a first wall portion defining at least a portion of a first lateral outer surface of the mobile phone, a second wall portion defining at least a portion of a second lateral outer surface opposite the first lateral outer surface, and a chassis portion extending between the first wall portion and the second wall portion. The mobile phone may further include a circuit board assembly thermally coupled to the chassis portion in a thermal coupling region of the chassis portion, the chassis portion defining a thermal path extending from the thermal coupling region to the first wall portion, and a through hole positioned in the thermal path and configured to interrupt a flow of heat from the circuit board assembly to the first wall portion. The through hole may define an elongated opening extending along a longitudinal axis, the longitudinal axis being parallel to the first outer surface of the mobile phone.The circuit board assembly may include a circuit board and a processor connected to a first surface of the circuit board, and the mobile phone may further include a thermal bridge thermally connected to a second surface of the circuit board and positioned below the processor, the second surface opposing the first surface. The thermal bridge may be thermally coupled to the chassis portion in the thermal coupling region.The circuit board assembly may be coupled to a first side of the chassis portion and positioned between the chassis portion and the back cover, the battery may be thermally coupled to the first side of the chassis portion and positioned between the chassis portion and the back cover, and the mobile phone may further include a heat diffusion element coupled to a second side of the chassis portion opposite the first side, the heat diffusion element positioned between the chassis portion and the front cover and configured to transfer heat from the display to the chassis portion. The heat diffusion element may include at least one layer of graphite adhered to the second side of the chassis portion.The circuit board assembly may include a first metal cover positioned on an outer surface of the circuit board assembly and covering a first circuit component, a second metal cover positioned on the outer surface of the circuit board assembly and covering a second circuit component, a heat diffusion element connected to the first metal cover and the second metal cover and spanning a gap between the first metal cover and the second metal cover, and a thermal bridge connected to the heat diffusion element and configured to thermally couple the circuit board assembly to the back cover.A portable electronic device may include a case comprising a front cover defining a front outer surface of the housing, a rear cover defining a rear outer surface of the housing, and a housing segment between the front cover and the rear cover including a first wall portion defining at least a portion of a first lateral outer surface of the housing, a second wall portion defining at least a portion of a second lateral outer surface opposite the first lateral outer surface, and a chassis portion connected to the first wall portion and the second wall portion and defining at least a portion of a first internal cavity between the chassis portion and the front cover and at least a portion of a second internal cavity between the chassis portion and the rear cover. The portable electronic device may further include a circuit board assembly positioned in the second interior cavity and connected to the chassis portion, wherein a first thermal bridge thermally connects the circuit board assembly to the back cover and a second thermal bridge thermally connects the circuit board assembly to the chassis portion. The chassis portion may include a through bore configured to interrupt a thermal path from the second thermal bridge to the first wall portion. The portable electronic device may further include a battery positioned in the second interior cavity and thermally coupled to the chassis portion. The through hole may form an elongated opening extending along a longitudinal axis, the longitudinal axis being parallel to the first lateral outer surface of the shell.The enclosure may further include a housing component coupled to the housing segment and defining at least a portion of an outer surface of a third side of the enclosure, the portable electronic device may further include a wireless communication device, and a portion of the housing component may be operatively coupled to the wireless communication device and operate as an antenna radiator. The front cover assembly may include a front cover, a display stack coupled to the front cover, a support frame coupled to the display stack, and a frame member formed from a molded polymeric material, the molded polymeric material at least partially encapsulating the support frame and defining an upper surface coupled to the front cover and a lower surface coupled to the housing segment. The housing component may include a housing portion adjacent a side of the front cover assembly, the rim portion defining a first region having a first thickness and a second region having a second thickness less than the first thickness, and the support frame may define a recessed region positioned opposite the first region of the rim portion. The second region of the edge portion may form at least a portion of the antenna radiator.An electronic device may include a front cover defining a front exterior surface of the electronic device, a display connected to an interior surface of the front cover, a rear cover defining a rear exterior surface of the electronic device, and a housing segment. The housing segment may include a chassis portion positioned between the front cover and the rear cover, a first wall portion positioned along a first side of the chassis portion and defining at least a portion of a first lateral outer surface of the electronic device, and a second wall portion positioned along a second side of the chassis portion and defining at least a portion of a second lateral outer surface of the electronic device. The electronic device may further include a circuit board assembly thermally coupled to a first side of the chassis portion and positioned between the chassis portion and the front cover, a battery thermally coupled to the first side of the chassis portion and positioned between the chassis portion and the rear cover, and a heat diffusion element coupled to the second side of the chassis portion and positioned between the chassis portion and the front cover, the heat diffusion element configured to transfer heat from the display to the chassis portion.The heat diffusion element may be configured to spread the heat of the display over the entire heat diffusion element. The heat diffusion element may include at least one layer of graphite and extends over at least 80% of the second side of the chassis portion.The circuit board assembly may be thermally coupled to the first side of the chassis portion in a thermal coupling region of the chassis portion, and the chassis portion may define a thermal path extending from the thermal coupling region to the first wall portion and a through hole extending through the chassis portion and interrupting the thermal path.The circuit board assembly may include a first metal cover positioned on an outer surface of the circuit board assembly and covering a first circuit component, a second metal cover positioned on the outer surface of the circuit board assembly and covering a second circuit component, and a heat diffusion member connected to the first metal cover and the second metal cover and spanning a gap between the first metal cover and the second metal cover. The circuit board assembly may further include a thermal bridge connected to the thermal diffusion element and configured to thermally connect the circuit board assembly to the back cover.A mobile phone may include a housing, a display at least partially located within the housing, a front cover connected to the housing and positioned over the display, and a rear cover connected to the housing. The back cover may define a first portion of a back outer surface of the mobile phone, a protrusion defining a raised sensor array region, the raised sensor array region defining a second portion of the back outer surface, a first hole defined by the protrusion in the raised sensor array region, a second hole defined by the protrusion in the raised sensor array region, and a third hole defined by the back cover outside the raised sensor array region. The mobile phone may further include a first camera lens assembly extending at least partially into the first hole, a second camera lens assembly extending at least partially into the second hole, and a flash module located at least partially within the housing and positioned outside of the raised sensor array region, wherein the flash module extends at least partially into the third hole.The back cover may further define a fourth hole defined by the protrusion in the raised sensor array region, and the mobile phone may further include a microphone module acoustically coupled to the fourth hole. At least a portion of the microphone module may be positioned outside the raised sensor array region.The mobile phone may further include a bracket connected to the back cover and at least partially defining an acoustic waveguide configured to acoustically couple the microphone module to the fourth hole. The bracket may include a base and a continuous wall extending from the base, and the continuous wall may abut the back cover to define the acoustic waveguide between the base and the back cover. The fourth hole may open into the acoustic waveguide at a first end of the acoustic waveguide, the holder may further include a fifth hole at a second end of the acoustic waveguide opposite the first end, and the fifth hole opens into the microphone module.The flash module may be connected to the bracket. The first hole and the second hole may be aligned along a first direction, and the third hole and the fourth hole may be aligned along a second direction perpendicular to the first direction.The first hole and the second hole may be oriented in a direction parallel to a lateral side of the mobile phone. The third hole may be equidistant from the first hole and the second hole.A portable electronic device may include a housing, a front cover connected to the housing and defining a front outer surface of the portable electronic device, a display below the front cover, and a rear cover connected to the housing. The back cover may define a first portion of a back outer surface of the wearable electronic device, a protrusion defining a raised sensor array region of the back cover, and a second portion of the back outer surface of the wearable electronic device, a microphone terminal defined by the back cover in the raised sensor array region, a first camera hole defined by the protrusion in the raised sensor array region, and a second camera hole defined by the protrusion in the raised sensor array region. The wearable electronic device may further comprise a camera assembly located at least partially within the housing and including a first lens assembly extending at least partially into the first camera hole and a second lens assembly extending at least partially into the second camera hole, and a microphone module coupled to the back cover along an inner surface of the back cover and acoustically connected to the microphone port, wherein at least a portion of the microphone module is positioned outside the raised sensor array region.The back cover may further define a flash hole through the back cover outside of the raised sensor array region, and the portable electronic device may further include a flash module connected to the back cover and extending at least partially into the flash hole.The camera assembly may include a camera housing, the camera housing defining a depression along a side of the camera housing, and the microphone module may include a shroud extending at least partially into the depression. The portable electronic device may further include a first camera associated with the first lens, a processing element, and a flexible circuit element operatively coupling the first camera to the processing element and extending along the side of the camera housing, wherein the flexible circuit element defines a notch aligned with the depression along the side of the camera housing, and the trim extends at least partially into the notch. The wearable electronic device may further include a bracket connected to the back cover and at least partially defining an acoustic waveguide configured to acoustically couple the microphone module to the microphone port. The bracket may include a wall defining a channel, and the wall abuts the back cover such that the acoustic waveguide is defined by the channel and the back cover.A mobile phone may include a shell comprising a housing having a top wall, a bottom wall opposite the top wall, a first side wall, and a second side wall opposite the first side wall. The mobile phone may further include a front cover connected to the housing and defining a front exterior surface of the mobile phone, a battery within the shell, a rear facing camera assembly positioned between the battery and the top wall and including a first lens assembly and a second lens assembly aligned along a first axis parallel to the first sidewall, a circuit board assembly having a first segment positioned between the battery and the top wall and a second segment positioned between the battery and the second sidewall, a processing element coupled to the circuit board assembly on the first segment between the battery and the top wall, and a haptic actuator positioned between the battery and the second sidewall, the haptic actuator including a mass configured to:, moving along a second axis parallel to the second sidewall to produce a haptic output.The mobile phone may further include a subscriber identity module (SIM) slot assembly connected to the circuit board assembly on the second segment of the circuit board assembly. The SIM slot assembly may include a SIM slot defining a SIM card cavity, and a longitudinal axis of the SIM card cavity may be parallel to the second sidewall.The mobile phone may further include a first acoustic module between the bottom wall and the battery and a second acoustic module between the bottom wall and the haptic actuator.A mobile phone may include a front cover defining a front outer surface of the mobile phone, a rear cover defining a rear outer surface of the mobile phone, and a housing positioned between the front cover and the rear cover and including a wall segment, the wall segment defining a through hole extending therethrough, the wall segment including a cover portion formed of a first metal. The enclosure portion may define a portion of a lateral outer surface of the mobile phone and a first portion of the through hole. The wall segment may further include a core portion connected to the shell portion and formed from a second metal different from the first metal, the core portion defining a counterbore extending through the core portion and aligned with the through hole, and a liner structure formed from the first metal and positioned in the counterbore in the core portion and fused to the shell portion in a fusion region, the liner structure defining a second portion of the through hole. The first metal may be a titanium alloy and the second metal may be an aluminum alloy.The fusion region may define a third portion of the through hole. The liner structure may be fused to the portion of the core within the counterbore bore. A seam between the liner structure and the core portion may be exposed in a sealed interior of the mobile phone. The mobile phone may further include an input member having a shaft, the shaft extending through the through hole in the wall segment, and a sealing member seated on the shaft and on a hole surface of the through hole to form a seal in the through hole.A portable electronic device may include a housing including a wall segment, the wall segment including a core portion formed of a first metal and defining a portion of an inner surface of the wall segment and a first hole extending through the core portion. The wall segment may further include a sheath portion connected to the core portion and made of a second metal different from the first metal, the sheath portion defining a portion of a lateral outer surface of the portable electronic device and a first portion of a second opening. The wall segment may further include a liner structure formed from the first metal and fused to the enclosure portion, the liner structure positioned within the first opening in the core portion and defining a second portion of the second opening.The second hole may be defined by a through hole surface, the liner structure may define a first portion of the through hole surface, and the enclosure portion may define a second portion of the through hole surface. The liner structure may be fused to the enclosure portion in a fusion region. The fusion region may define a third portion of the through hole surface between the first portion and the second portion. The through hole surface may be a through processed surface defined along the cladding portion, the fusion region, and the liner structure.The liner structure may be fused to the cladding portion by laser melting. The first metal may be an aluminum alloy and the second metal may be a titanium alloy. The liner structure may be fused to the core portion along a hole surface of the first hole.An electronic device may include a front cover defining a front exterior surface of the electronic device, a display below the front cover, a rear cover defining a rear exterior surface of the electronic device, and a housing positioned between the front cover and the rear cover. The housing may include a wall segment, the wall segment defining a first hole extending through the wall segment. The wall segment may include a sheath portion formed from a first metal and defining a portion of a lateral surface of the electronic device, a core portion formed from a second metal and fused to the sheath portion and defining a portion of an inner surface of the electronic device, and a second hole through the core portion, the second hole extending from the inner surface to the sheath portion. The wall segment may further include a liner structure positioned in the second hole and fused to the enclosure portion in a fusion region. The enclosure portion may define a first portion of a hole surface of the first hole, the liner structure may define a second portion of the hole surface of the first hole, and the fusion region between the enclosure portion and the liner structure may define a third portion of the hole surface of the first hole.The hole surface may be a continuously machined surface. The first metal may be a titanium alloy and the second metal may be an aluminum alloy.The liner structure may be melt-adhered to the covering portion. The core portion may be diffusion bonded to the cladding portion.The electronic device may further include an input member defining a shaft, the shaft extending into the first hole, and a sealing member seated on the shaft and the hole surface of the first hole to define a seal between a sealed internal volume of the electronic device and an external environment, and a seam between the liner structure and the portion of the core may be within the sealed internal volume of the electronic device.A mobile phone may include a shell having a front cover assembly defining a front outer surface of the shell and a housing structure connected to the front cover assembly and defining a lateral outer surface of the shell, the housing structure including a conductive attachment structure. The mobile phone may further include a battery in the shell and an electrically removable adhesive structure removably connecting the battery to the conductive attachment structure and including a conductive layer connected to the battery and an electrically removable adhesive layer adhered to the conductive layer and to the conductive attachment structure. The electrically releasable adhesive layer may have a first surface adhered to and conductively connected to the conductive layer and a second surface adhered to and conductively connected to the conductive attachment structure, the electrically releasable adhesive layer configured to decrease its adhesion along the first surface and / or the second surface in response to a voltage potential applied to the electrically releasable adhesive layer via the conductive layer and the conductive attachment structure.The conductive mounting structure may include an aluminum alloy and may have a first region with an anodized surface and a second region with a passivated conductive surface. The electrically releasable adhesive layer may be adhered to the passivated conductive surface. The conductive layer may be adhesively bonded to the battery along a first side of the conductive layer and adhesively bonded to the electrically releasable adhesive layer along a second side of the conductive layer.The conductive layer may include a flexible substrate and a conductive material disposed on the flexible substrate. The conductive layer may form a tab extending from the electrically releasable adhesive structure, the tab including a conductive terminal for connection to a voltage source. The conductive terminal may be a first conductive terminal, and the package structure may define a second conductive terminal for coupling to the voltage source.The electrically releasable adhesive layer may be configured to decrease its adhesion strength along the second surface in response to a voltage potential applied to the electrically releasable adhesive layer via the conductive layer and the conductive attachment structure.A portable electronic device may include a front cover defining a front outer surface of the portable electronic device, a display device coupled to an inner surface of the front cover, a housing structure coupled to the front cover and including a conductive attachment structure below the front cover, a battery, an electrically releasable adhesive coupling the battery to the conductive attachment structure, a first electrode conductively connected to a first surface of the electrically releasable adhesive, the first electrode defined by the conductive attachment structure, and a second electrode conductively connected to a second surface of the electrically releasable adhesive, the electrically releasable adhesive configured to decouple the battery from the conductive attachment structure in response to a voltage potential applied between the first electrode and the second electrode.The battery may include a conductive battery shell and a battery cell within the conductive battery shell, and the second electrode may be defined by the conductive battery shell. The conductive battery shell may include a lower metal-molded shell structure and an upper metal-molded shell structure welded to the lower shell structure. The battery may include a positive terminal conductively connected to a cathode of the battery cell and conductively insulated from the conductive battery shell, and the conductive battery shell may be conductively connected to an anode of the battery cell.The second electrode may be defined by a conductive layer positioned between the electrically degradable adhesive and the battery.The housing structure may include a first wall portion defining at least a portion of a first lateral outer surface of the portable electronic device and a second wall portion defining at least a portion of a second lateral outer surface of the portable electronic device opposite the first lateral outer surface, and the conductive attachment structure may extend from the first wall portion to the second wall portion. The conductive mounting structure may be formed from an aluminum alloy and may include a first region of the surface having an anodized surface and a second region of the surface having a passivated conductive surface. The electrically releasable adhesive may be adhered to the passivated conductive surface.The portable electronic device may further include switching circuitry operatively connected to the battery and the first electrode and the second electrode and configured to apply the voltage potential between the first electrode and the second electrode of the battery.An electronic device may include a touchscreen display, a battery, a case enclosing the touchscreen display, and the battery. The shell may include a front cover assembly defining a front outer surface of the shell, a housing structure connected to the front cover assembly and a first wall portion defining at least a portion of a first outer surface of the shell, a second wall portion defining at least a portion of a second outer surface opposite the first outer surface, and a conductive chassis portion connected to the first wall portion and the second wall portion. The electronic device may further include an electrically releasable adhesive conductively connected to the conductive chassis portion and connecting the battery to the conductive chassis portion, and a conductive layer between the electrically releasable adhesive and the battery conductively connected to the electrically releasable adhesive, the electrically releasable adhesive configured to release from the conductive chassis portion in response to a voltage potential applied between the conductive chassis portion and the conductive layer.The conductive chassis portion may be formed of an aluminum alloy and may include a first region having an anodized surface and a second region having a passivated conductive surface. The electrically releasable adhesive may be adhered to the passivated conductive surface.The electronic device may further include a terminal configured to receive a charging cable configured to supply the voltage potential, and the terminal may be operatively connected to the conductive chassis portion and the conductive layer. The electronic device may be configured to apply the voltage potential of the charging cable to the conductive chassis portion and the conductive layer in response to a user input. The user input may be provided on the touchscreen display.The conductive chassis portion may form an electrical ground of the electronic device. The conductive layer may include a flexible substrate and a conductive material disposed on a surface of the flexible substrate.BRIEF DESCRIPTION OF THE DRAWINGSThe disclosure will be readily understood from the following detailed description taken in conjunction with the accompanying drawings, in which like reference numerals designate like structural elements, and in which: FIGS. 1A-1B show an example of an electronic device. FIGS. 1C-1D show another example of an electronic device. FIG. 2 is an exploded view of an exemplary electronic device. FIG. 3 is an exploded view of an example electronic device. FIG. 4A is a top view of an example package structure of an electronic device. FIG. 4B is a partial exploded view of an example electronic device. FIG. 4C is a partial cross-sectional view of an electronic device. FIGS. 5-6 show an example of a circuit board assembly of an electronic device. FIG. 7A shows an example of the battery of an electronic device. FIG. 7B is a partial exploded view of an example battery of an electronic device. FIGS. 7C-7D are partial cross-sectional views of an example battery of an electronic device. FIGS. 8A-8B show a portion of an example electronic device with a rear facing sensor array. FIG. 8C shows an example of a rear facing camera assembly. FIG. 8D shows a portion of an example rear cover assembly for an electronic device. FIG. 9 shows an example of a mount for use with a strobe and microphone module for an electronic device. FIG. 10A is a partial cross-sectional view of a housing component having a shrouded construction. FIGS. 10B-10F are partial cross-sectional views of a housing illustrating example operations for forming a liner structure in a housing. FIGS. 11A-11B are partial cross-sectional views of a housing illustrating further example operations for forming a liner structure in a housing. FIG. 12A is a front view of an example electronic device. FIG. 12B is a perspective view of a portion of an example housing of an electronic device. FIG. 13A is a partial cross-sectional view of an apparatus including an example input key system. FIG. 13B is a perspective view of a portion of an example input key system. FIG. 13C is a partial exploded view of an apparatus including an example input key system. FIGS. 14A-14B are partial cross-sectional views of an example input key system. FIG. 15 is an exploded view of an exemplary input structure of an input key system. FIGS. 16A-16C are partial cross-sectional views of an apparatus including an example input key system. FIGS. 17A-17B are perspective views of a portion of a device including an example input key system. FIGS. 18A-18F are partial cross-sectional views of an input key system illustrating example inputs to the input key system. FIG. 19 is a partial cross-sectional view of an example input key system. FIG. 20A shows an example of a rear-facing sensor system of an electronic device. FIG. 20B is an exploded view of an example of a flexible circuit package. FIG. 21A shows an electronic device including an example circuit group. FIG. 21B shows an example circuit group for an electronic device. FIG. 21C shows an example of a spacer for use with a circuit group of an electronic device. FIG. 21D shows an example circuit group for an electronic device. FIG. 21E shows an example circuit group for an electronic device. FIG. 22A is a perspective view of an example rear cover assembly for an electronic device. FIG. 22B is a perspective view of an example rear cover assembly for an electronic device. FIG. 23 shows an example of the arrangement of components for an electronic device. FIG. 24A is a partial exploded view of an electronic device illustrating an example of an electrically releasable adhesive structure for attaching a component to a housing. FIG. 24B is a rear view of a portion of an electronic device having an electrically releasable adhesive structure. FIGS. 25A-25D are partial cross-sectional views of an example electrically releasable adhesive structure illustrating example adhesive detachment operations. FIG. 26A is a partial cross-sectional view of a device illustrating an example of an electrically degradable adhesive structure. FIG. 26B is a partial cross-sectional view of an example battery and an example of an electrically releasable adhesive structure. FIG. 27 is a partial cross-sectional view of an exemplary electronic device having electrically releasable adhesive structures that connect the front and back covers to a housing. FIGS. 28A-28D are partial cross-sectional views of examples of electrically degradable adhesive structures. FIGS. 29A-29B illustrate heating elements for use with electrically sealable adhesive structures. FIG. 29C is a partial cross-sectional view of an example of an electrically degradable adhesive structure with a heater installed. FIGS. 30A-30E show example configurations for applying a voltage source to an electrically sealable adhesive structure. FIG. 31 shows an example user interface for initiating detackification operations for electrically decalsable adhesive structures. FIG. 32 is a schematic illustration of an example electronic device.DETAILED DESCRIPTIONReference 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 a preferred embodiment. On the contrary, it is intended to cover alternatives, modifications, and equivalents as may be included within the spirit and scope of the described embodiments as defined by the appended claims.The mobile phones described herein may include complex, sophisticated components and systems that enable a variety of functions. For example, mobile phones according to the present disclosure may include touch and / or force sensitive displays, various cameras (including front and rear facing cameras), GPS systems, haptic actuators, wireless charging systems, and any required computer systems and software to operate these (and other) systems and otherwise provide the functionality of the mobile phones.FIGS. 1A and 1B show an exemplary electronic device 100 in the form of a mobile phone. FIG. 1A illustrates a front side of the device 100, while FIG. 1B illustrates a rear side of the device. Although the device 100 is a cellular phone, the concepts presented herein may be applied to any suitable electronic device, including portable electronic devices, portable devices (e.g., watches), laptops, portable gaming devices, tablet computers, computer peripherals (e.g., mice, touchpads, keyboards), or any other device. Accordingly, any reference to an "electronic device" includes all of the above items.The electronic device 100 includes a cover 102 (e.g., a front cover) that is attached to a housing 104 (which may include a housing structure defined by one or more housing components). The cover 102 may be positioned over a display 103. The cover 102 may be a sheet or sheet-like structure formed from or including a transparent or optically transmissive material. The cover 102 may form a front exterior surface of the device and an interior surface opposite the exterior surface. In some cases, the cover 102 is formed from or includes a glass material and may therefore be referred to as a glass cover element. The glass material may be silica-based glass material, aluminosilicate glass, borosilicate glass, alkali metal aluminosilicate glass (e.g., lithium aluminosilicate glass), or chemically strengthened glass. Other example materials for the cover 102 include, without limitation, sapphire, ceramic, glass ceramic, crystallizable glass materials, or plastic (e.g., polycarbonate). A glass ceramic material may be silica-based glass ceramic material, such as an aluminosilicate glass ceramic material or a borosilicate glass ceramic material. The glass ceramic material can be chemically hardened by ion exchange. The cover 102 may be formed as a monolithic or one-piece sheet. The cover 102 may also be formed as a composite of multiple layers of different materials, compositions, and other elements.The display 103 may be positioned at least partially within the interior volume of the housing 104. The display 103 may be connected to the cover 102, for example, by an adhesive or other connection system. The display 103 may include a liquid crystal display (LCD), a light emitting diode display (LED), an organic light emitting diode display (OLED), an active layer organic light emitting diode display (AMOLED), an organic electroluminescence display (EL), 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 can view and interact with. Graphical outputs may be displayed in a graphically active region of the display 103 (e.g., an active display region). The active display region may be surrounded or bounded by an edge region that may be defined by an opaque mask on the inner surface of the cover 102 (or by other components or techniques). In some cases, the edges are small (e.g., less than about 3 mm, less than about 2 mm, or less than about 1 mm).The display 103 may also define a primary display region, which may generally correspond to the forward-facing, contiguous main display region, in which graphical user interfaces, images, videos, applications, and other graphical outputs may be displayed.The device 100 may also include an ambient light sensor that may determine the characteristics of the ambient light conditions around the device 100. 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 hue, brightness, saturation, or other optical aspects of the display based on information from the ambient light sensor). The ambient light sensor may be positioned below an active area of the display 103 (e.g., below a portion of the display that provides a graphical output). The ambient light sensor may transmit and / or receive light through the active area of the display 103 to perform sensing functions.The display 103 may include or be associated with one or more touch-sensitive and / or force-sensing systems. In some cases, components of the touch and / or force sensor system are integrated into the display stack. For example, touch-sensitive components, such as electrode layers of a touch and / or force sensor, may be provided in a stack that includes display components (and optionally attached to or at least visible through the cover 102). The touch and / or force sensor systems may use any suitable type of sensor technology and touch sensitive components, including capacitive sensors, resistive sensors, surface acoustic wave sensors, piezoelectric sensors, strain gauges, or the like. The outer surface of the cover 102 may form an input surface (e.g., a touch and / or force sensitive input device) of the device. Although both touch-sensitive and force-sensitive systems may be included, it may occur that the device 100 includes a touch-sensitive system and not a force-sensitive system.The device 100 may also include a front-facing camera 106. The forward facing camera 106 may be positioned under or otherwise covered and / or protected by the cover 102. The forward facing camera 106 may have any suitable operating parameters. For example, the front-facing camera 106 may include a 12 megapixel sensor (having a pixel size of 1 micron) and a field of view of 80-90°. The forward facing camera 106 may have a f / 1.9 aperture. The forward facing camera 106 may include an autofocus function (e.g., one or more lens elements may move relative to an optical sensor to focus an image on the sensor). Other types of cameras may also be used for the forward-facing camera 106, such as a fixed focus camera.The forward facing camera 106 (as well as other components) may be positioned in a forward facing sensor region 111. The forward facing sensor region 111 may be positioned in an island-like region of the front of the device 100 and may be surrounded by a display region (e.g., a main or primary display region) of the device 100. In some cases, as described herein, the forward sensor region 111 may be positioned in or defined by one or more holes formed through the display 103. In such cases, the forward facing sensor region 111 may be bounded on all sides by active areas or regions of the display 103. In other words, the forward facing sensor region 111 may be completely surrounded by display active regions (e.g., an outer perimeter of the forward facing sensor region 111 may be surrounded by display active regions). In some cases, the forward-facing sensor region 111 includes or is defined by one or more masks or other visually opaque components or treatments defining openings for the sensors of the forward-facing sensor region 111. The forward-facing sensor region 111 may include components such as an infrared lighting module 107 (which may include a flood light emitter and a spot projector), an infrared image capture device 109, components of a proximity sensing system 123, and the forward-facing camera 106. The infrared illumination module 107 is an example of a light transmitter, and the image capturing device 109 is an example of an optical receiver.The proximity sensing system 123 may determine the proximity of an object (e.g., a user's face) to the device 100. The device 100 may use information from the proximity sensing system 123 to modify, modify, adjust, or otherwise control the display 103 or other functions of the device 100 (e.g., to deactivate the display when the device 100 is held near a user's face during a phone call). The proximity sensing system 123 may be part of an integrated module that includes components of the proximity sensing system 123, as well as the illumination module 107 and the infrared imaging device 109. The proximity sensing system 123 may include an optical transmitter and an optical receiver, each of which may be associated with a separate light guide. The proximity sensing system 123 may estimate the distance between the device and a separate object or target using lasers and time-of-flight calculations or other components or techniques of proximity detection.In some cases, the forward sensor region 111 is defined by or includes two holes formed through the display 103, for example, a first hole to provide optical access to the forward camera 106 and a second hole to provide access to the infrared lighting module 107, the image capture device 109, and the proximity sensing system 123. An additional display region 115 may be located between the first and second holes. The additional display region 115 may provide graphical output and a touch and / or force sensing function to the forward sensor region 111. For example, the additional display region 115 may be used to display graphical outputs such as lights, shapes, icons, or other items (e.g., to provide notifications and / or information to the user). In some cases, the additional display region 115 may be visually distinguished from other active regions of the display, such that the additional display region 115 does not appear as part of the display. For example, graphical outputs (e.g., graphical user interfaces, images, videos, etc.) displayed on the display 103 may not extend into the additional display region 115. In such cases, the forward facing sensor region 111 may appear visually as a single contiguous area of the display, although the display has two separate holes separated by an active display region or an active area. The additional display region 115 and optionally the touch sensitive components of the display surrounding the forward facing sensor region 111 may also include touch and / or force sensing functionality such that a user may touch the forward facing sensor region 111 to provide input to the device. In some cases, touch inputs made anywhere in the forward-facing sensor region 111 (e.g., also directly above the optical components) may be detected by the device. These and other features of the forward facing sensor region 111 are described herein.The device 100 may also include one or more buttons (e.g., button 120, button 121, and buttons 116 and 118 in FIG. 1B ), switches, and / or other physical input systems. Such input systems may be used to control the power state (e.g., key 120), control applications (e.g., key 121), change speaker volume (e.g., key 116), switch between "ring" and "mute" modes (e.g., key 118), and the like. The buttons 116, 118, 120, and 121 may include strain sensing systems that sense inputs to the buttons based on a sensed strain. The buttons 116, 118, 120, and 121 may also be associated with haptic actuation systems that generate a tactile output in response to sensing a load that satisfies a particular condition. For example, upon sensing a strain or force that satisfies a condition (and / or an electrical parameter indicative of a strain that satisfies the condition), a haptic actuator system may apply a force to a button to produce a tactile output (e.g., similar to a "click"). This tactile output or response may provide tactile feedback to the user to indicate that the input has been detected by the device.In some cases, one or more of the buttons 116, 118, 120, and 121 may use switch elements, such as hinged dome switches, to detect keystrokes. Such dome switches may be used in place of (and optionally in addition to) strain-based or other non-binary force sensors. However, in some cases, in addition to the strain-based or non-binary force sensors, dome switches or other hinged or tactile switches may also be used in a particular button. In such cases, the key may facilitate the detection of binary or instantaneous inputs while detecting the magnitude of a force applied to the key. In such cases, the device 100 may perform different operations in response to detecting the binary input and in response to detecting a force that satisfies a condition. In particular, a user may provide a partial actuation of the button (e.g., a half click or half press) in which a force is applied but the switch is not folded. The device 100 may perform one or more operations in response to detecting partial actuation of the button (e.g., in response to detecting a force that satisfies a condition). A user may subsequently (or instead) provide a full actuation of the button, where the force is increased until the switch is actuated or another input is registered (e.g., the dome switch folds together). The device 100 may perform one or more additional or other operations in response to detecting the switch actuation. As a non-limiting example, the button may be used to provide input to the device 100 when the device 100 is operating in an image capture mode. In such cases, a partial operation may cause the apparatus 100 to initiate a focusing operation or disable an exposure setting for image capturing (or perform other operations or combinations of operations). When the full actuation is detected (e.g., when the binary or button is actuated), the device 100 may capture an image with one of the built-in cameras. In response to the partial and / or full actuation of the button, other functions may also be initiated, including other image capture functions or other device or application functions. For example, a partial actuator may initiate scroll (e.g., browsing through entries in a displayed list) and a full actuator may initiate selection of a selected entry in the list. In some cases, the key 121 of the device 100 includes both a dome switch (or other binary or momentary switch) and a stretch-based sensing system. In some cases, one or more other keys of the device 100 include both a dome switch (or other binary or momentary switch) and a strain-based sensing system.In some cases, one or more of the buttons 116, 118, 120, and 121 may use touch sensing systems, such as capacitive touch sensing systems, to sense inputs. For example, the tactile element of a button (e.g., the movable component that a user presses to actuate the button or provide input) may include a touch sensitive element positioned thereon. A key equipped with a touch-sensitive element may sense various types of touch-based inputs, including static touch inputs (e.g., a finger touching the touch-sensitive surface of the key), dynamic touch inputs (e.g., a finger sliding over the touch-sensitive surface of the key, also referred to as gesture or stroke inputs), or the like.In some cases, the button 121 may include a touch sensitive element 131 to sense such touch-based inputs. The device 100 may perform various operations in response to sensing touch-based inputs. Continuing the above example: When the device 100 is operating in an image capture mode, a static touch input may initiate a focus or exposure lock, while a dynamic or swiping touch input may initiate a zoom operation (e.g., swiping in one direction may initiate a zoom-in operation and swiping in the opposite direction may initiate a zoom-out operation).In some cases, the touch sensitive element 131 may detect the location of an input on the button 121 during a key operation, and the device may perform various actions based on the location of the touch. For example, when the button 121 is operated with an input at a first location on the button 121 (e.g., at an end of the button 121 as detected by the touch-sensitive element 131), the device may perform a first action (e.g., a magnifying operation), and when the button 121 is operated with a press input at a second location on the button 121 (e.g., at an opposite end of the button 121 as detected by the touch-sensitive element 131), the device may perform a second action different from the first action (e.g., a reducing operation).In some cases, the touch element 131 may detect whether input to the key 121 is made with one finger or with two fingers, and may then perform different operations. For example, when the single finger key 121 is actuated (as detected by the touch-sensitive element 131), the device may perform a first action (e.g., capture a single image), and when the multi-finger key 121 is actuated (as initiated by the touch-sensitive element 131), the device may perform a second action different from the first action (e.g., capture a sequence of images for the duration of the actuation or initiate a video capture operation).Other sensing techniques may also be used to detect inputs to the keys. In some cases, a switch or other input device is used instead of one or more buttons.As mentioned above, the button 121 may be force and / or pressure sensitive (e.g., capable of detecting variable force inputs) and may generate multiple controls or outputs based on the amount of force input, the presence of a touch, the location of the touch, and the movement of the touch (gesture). The particular operation initiated in response to a particular key input may vary in accordance with (e.g., proportional to) the applied force. In some cases, a force-based input without a sensed touch input at touch-sensitive element 131 may suppress an action or be ignored by the device. The button 121 may also be coupled to one or more other buttons for designated operations or commands (e.g., the device may perform certain operations in response to detecting simultaneous inputs to multiple buttons or certain sequences of inputs to multiple buttons).As described above in several examples, the button 121 may be used to initiate or control image capture functions and operations. For example, a light touch of the button 121 (e.g., a sensed touch input without force or with a force that satisfies a first force state corresponding to a light deflection of the button) may initiate a sharpness and exposure measurement operation, and a larger force or deflection of the button (e.g., that satisfies a second force state) may initiate an image or video capture operation. Additionally, different haptic outputs may be generated in response to detecting different inputs at the button 121 and / or in response to the different operations initiated by the button inputs.Other examples of image manipulations and / or camera function controls that may be initiated by inputs to the key 121 (force and / or touch inputs) include increasing or decreasing in response to swiping inputs on the key surface in different directions; increasing or decreasing volume in response to inputs on the key input surface in different directions; capturing a single image or a series of multiple images in response to different force inputs (e.g., a single light press image, multiple stronger press images). In such cases, different haptic outputs may be generated in response to detecting different inputs to the button 121 and / or in response to the different operations initiated by the button inputs.The button 121 may also result in the device performing other functions that are either linked to the operation of the device or set in response to operation of a particular application or mode of use of the phone. For example, inputs on button 121 may cause the device to perform operations such as: selecting one or more alarm suppression modes (muting); checking purchase or checking application commands; controlling timer commands including clock-related operations; providing inputs to games such as throttle control or other continuously variable inputs; initiating hard and / or soft reset of the device; initiating user programmable operations; and starting or ending applications. In some cases, the particular function of the key may be programmed or selected by the user. For example, a user may select which functions or operations are initiated in response to various force inputs, gesture inputs, and touch inputs. The user may also specify different input schemes for different modes of the device. For example, the user may associate force, touch, and gesture inputs with a first set of functions when the device is operating in a first mode (e.g., when a first application is executing, such as an image capture application), and may associate force, touch, and gesture inputs with a second set of functions when the device is operating in a second mode (e.g., when a second application is executing).In some cases, the function of the button 121 may change based on the orientation of the device. For example, the force, touch, and gesture inputs may be associated with a first set of functions when the device is maintained vertical or in portrait format, and the force, touch, and gesture inputs may be associated with a second set of functions when the device is maintained horizontal or in landscape format.".The key 121 may also be used to initiate stereoscopic image or video capture. In some cases, selection of a stereoscopic image capture mode (or switching between stereoscopic and non-stereoscopic image modes) may be controlled by operation of the button 121 or other inputs of the device (e.g., other buttons, touch screen inputs, etc.). In some cases, the ability to select (or transition between a stereoscopic image mode and other image modes) a stereoscopic image mode with the key 121 may depend on the orientation of the device.The device 100 may also include a speaker port 110 to provide audio output to a user, such as a user's ear in voice calls. The loudspeaker connection 110, which is an example of an audio connection, can also be referred to as a receiver, receiver connection or listener in connection with a mobile telephone. The speaker port 110 may be formed by an opening bounded along at least one side by the housing 104 and along at least one other side by the cover 102. In some cases, the cover 102 defines a notch along an edge of the cover, and the notch (also referred to as a depression or cut-out) defines at least three sides of the speaker port 110. Speaker port 110 may not have a mesh or other cover flush with the front surface of cover 102. In some cases, a guard grid is positioned in the device 100 and in a path between a speaker and the speaker port 110 to inhibit ingress of debris into the device 100. The guard grid or grid may be recessed from the surface or front of the cover 102.The device 100 may also include a charging port 112 (e.g., for receiving a port of a charging or power cable to provide power to the device 100 and charge the battery of the device 100). The charging port 112 may receive a connector of any type. In some cases, the charging port 112 receives a port conforming to a Universal Serial Bus (USB) plug type, such as a USB-C plug. The charging port 112 may also be configured to transmit and / or receive data over a cable, such as with a USB or other communication protocol.The device 100 may also include audio openings 114. Through the audio openings 114, the sound output from an internal speaker system (e.g., speaker system 224, FIG. 2 ) may 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 connected to the environment through an audio aperture 114.The housing 104 may be a multi-piece housing. For example, the housing 104 may be formed from a plurality of housing components 124, 125, 126, 127, 128, and 130 structurally interconnected via one or more intervening elements, such as hinge structures 122 (e.g., 122- 1- 122- 6). Together, the housing components 124, 125, 126, 127, 128, and 130 and the connection structures 122 may form a ribbon-like housing structure defining four side walls (and thus four outer side surfaces) of the device 100. The four walls may include a top wall (e.g., proximate to the forward-facing sensor array 111), a bottom wall opposite the top wall (e.g., proximate to the port 112), a first side wall (e.g., a first face side visible in FIG. 1A ), and a second side wall opposite the first side wall (e.g., a second face side visible in FIG. 1B ). Thus, both the package components and the interconnect structures define portions of the exterior side surfaces of the device 100.The package components 124, 125, 126, 127, 128, and 130 may be formed of a conductive material (e.g., a metal) and the interconnect structures 122 may be formed of one or more polymeric materials (e.g., glass reinforced polymer). The connection structures 122 may include two or more molded elements that may be made of different materials. For example, an inner molding member may be formed from a first material (e.g., a polymeric material) and an outer molding member may be formed from a second material different from the first (e.g., a different polymeric material). The materials may have different properties that may be selected based on the different functions of the inner and outer mold members. For example, the inner molded element may be configured to provide the main structural connection between the components of the housing, and may have a higher mechanical strength and / or toughness than the outer molded element. On the other hand, the outer molded member may be configured to have a certain appearance, surface area, chemical resistance, waterproof function or the like, and its composition may be selected to give preference to the mechanical strength among these functions. The connecting structures 122 may be mechanically interlocked with the housing components to structurally connect the housing components and form a structural housing assembly.The housing components 124, 125, 126, 127, 128, and 130 may be formed from a packaging structure that includes a plurality of materials. For example, the housing components may include a core portion formed from a first metal and a sheath portion formed from a second metal. The enclosure portion may define outer surfaces of the housing components. The outer surface defined by the enclosing portion may have a surface structure that creates a specific visual appearance and / or a specific haptics. For example, the surface texture may include a texture that creates diffuse reflections. The surface texture may be created by grinding, lapping, machining, ablation, blasting (e.g., sandblasting, pearlescent), etching (by mechanical etching, laser etching, chemical etching), or other suitable texturing methods. The exterior surface of the housing components may also include a coating, such as an applied coating. In some cases, the sheath portion is polished. The coating may be applied to the package components by plasma vapor deposition (PVD), chemical vapor deposition (CVD), or the like.The core portions of the housing components may be made of aluminum (e.g., an aluminum alloy) and the cladding portions may be made of titanium (e.g., a titanium alloy). Other metals may be used for the core and cladding portions instead of aluminum and titanium, such as an aluminum core having a stainless steel cladding, a nickel core having a titanium cladding, or a steel core having a stainless steel cladding. Other metals and combinations of metals are also conceivable. In some cases, the core portions of the housing components are made of aluminum and the cladding portions are made of stainless steel. The sheath portions may have an average thickness between about 0.1 mm and about 1.0 mm. The aluminum of the housing may include reused aluminum (e.g., up to 70% reused aluminum, up to 85% reused aluminum, or another value).Unless otherwise indicated herein, reference to a metal (e.g., aluminum, titanium) includes both pure metals and metal alloys. For example, a component formed of aluminum may be pure aluminum, a 6061 aluminum alloy, a 7071 aluminum alloy, or another aluminum alloy. Likewise, a component formed of titanium may be pure titanium, a Ti-6Al-4V titanium alloy, a Ti-5Al-2.5Sn titanium alloy, or another titanium alloy. With respect to steel, various types and / or alloys of steel may be included, including, but not limited to, low carbon steel, stainless steel, high carbon steel, etc.In some cases, one or more of the housing components 124, 125, 126, 127, 128, and 130 (or portions thereof) are configured to operate as antennas (e.g., components configured to transmit and / or receive electromagnetic waves to facilitate wireless communication with other computers and / or devices). To facilitate use of the package components as antennas, power and ground lines may be conductively connected to the package components to couple the package components to other antennas and / or communication circuitry. The interconnect structures 122 may be substantially non-conductive to provide suitable isolation and / or electrical isolation between the package components (which may be used to tune the radiating portions, reduce capacitive coupling between radiating portions and other structures, and the like). In some cases, additional antenna segments are conductively connected to the package components to alter an antenna performance parameter of the package component. Additional antenna segments may be coupled to the package components via switching circuitry that enables the additional antenna segments to be selectively coupled to or decoupled from the package components.The device 100 may include various internal antenna elements configured to transmit and receive wireless communication signals over different regions of the device 100. For example, internal antenna elements may be configured to transmit and receive wireless communication signals via front cover 102, rear cover 132 (FIG. 1B ), or optionally, via frequency transmissive windows formed by housing components.The exterior surfaces of the housing components 124, 125, 126, 127, 128, and 130 may have substantially the same color, surface texture, and overall appearance as the exterior surfaces of the interconnect structures 122. In some cases, the outer surfaces of the housing components 124, 125, 126, 127, 128, and 130 and the outer surfaces of the interconnect structures 122 are subjected to at least one common finishing process, such as blasting, machining, polishing, grinding, or the like. Accordingly, the exterior surfaces of the package components 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 components and the joint structures may be subjected to a two-step blasting process to produce the desired surface finish.FIG. 1A also includes an example of a coordinate system 101 that may define directions with respect 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 otherwise indicated, references to a positive x, positive y, or positive z direction generally refer to the coordinate system 101 and its relationship to the device 100 in FIG. 1A. Negative x, y and z directions are to be understood as being opposite to the positive x, y and z directions shown in the coordinate system in Fig. 1A. The x, y and z directions can also be understood as x, y and z axes.FIG. 1B illustrates a back side of the device 100. The device 100 may include a back cover 132 connected to the housing 104 and defining at least a portion of the exterior surface of the device 100. The cover 102 (e.g., the front cover), the back cover 132, and the housing 104 may at least partially form a shell of the device 100. The shell may define an interior volume in which components of the device 100 are positioned. The back cover 132 may be formed from or include a transparent or optically transmissive material. For example, the back cover 132 may include a substrate formed of a glass material. The glass material may be silica-based glass material, aluminosilicate glass, borosilicate glass, alkali metal aluminosilicate glass (e.g., lithium aluminosilicate glass), or chemically strengthened glass. Other example materials for the back cover 132 include, without limitation, sapphire, ceramic, glass ceramic, crystallizable glass materials, and plastic (e.g., polycarbonate). A glass ceramic material may be silica-based glass ceramic material, such as an aluminosilicate glass ceramic material or a borosilicate glass ceramic material. The glass ceramic material can be chemically hardened by ion exchange.The back cover 132 may be formed as a monolithic or one-piece sheet. The back cover 132 may also be formed as a composite of multiple layers of different materials, compositions, and other elements. The back cover 132 may include one or more decorative layers on the outer or inner surface of the substrate. For example, one or more layers may be applied (or otherwise positioned along the inner surface of the substrate) to provide a particular appearance to the back side of the device 100. The coating layer(s) may include a sheet, ink, dye, or combinations of these (or other) layers, materials, or the like. In some cases, one or more of the layers have a color substantially corresponding to the color of the housing 104 (e.g., the exterior surfaces of the housing components and the interconnect structures). In some cases, the material of the substrate of the back cover 132 may be colored and include one or more coatings that contribute to the colored appearance of the back cover. Moreover, the back cover 132 may be formed from or include a dielectric material (e.g., the back cover 132 may be a dielectric element such as a glass material, sapphire, polymer material, glass ceramic, etc.).The device 100 may include a wireless charging system, where the device 100 may be powered and / or its battery charged through inductive (or other electromagnetic) coupling between a charger (e.g., a wireless charging accessory) and a wireless charging system within the device 100. In such cases, the back cover 132 may be formed of a material that facilitates and / or facilitates wireless coupling between the charger and the wireless charging system.The apparatus 100 may also include a sensor array 141 (e.g., a rear facing sensor array in a rear facing region) that includes three cameras (e.g., as shown in FIG. 2 and described herein). The sensor array 141 may be located in a sensor array region defined by a protrusion 151 in a back cover of the device 100. The protrusion 151 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 141. In some cases, the protrusion 151 may be formed by attaching one piece of material (e.g., glass) to another piece of material (e.g., glass). In other cases, the back cover 132 may include a monolithic structure, and the protrusion 151 may be part of the monolithic structure. For example, the back cover 132 may include a monolithic glass structure (or a glass ceramic structure or an alkali aluminum silicate structure or other suitable material) defining the protrusion 151 as well as the surrounding area. In such cases, the protrusion 151 may be a region of increased thickness of the monolithic structure, or may have the same or substantially the same thickness as the rest of the cover (e.g., the protrusion 151 may correspond to or generally oppose a recessed region along an inner side of the monolithic structure such that the monolithic structure has a uniform thickness and simultaneously defines the protrusion 151).The first camera 142 may include a 12 megapixel sensor and a tri-optical zoom telephoto lens with an aperture of f / 2.8. In some cases, the first camera 142 includes a telephoto lens having a 5-fold optical zoom. A second camera 144 may include a 48.8 megapixel sensor (optionally with a three layer sensor array) with sensor shift image stabilization and a wide angle lens with an aperture of f / 1.7. A third camera 146 may include a 48 megapixel sensor and a super wide angle camera with a large field of view (e.g., 120° FOV) and a f / 2.2 aperture. One or more of the cameras of the sensor array 141 may also include lens-based optical image stabilization in which the lens is dynamically moved relative to a fixed structure within the device 100 to reduce the effects of "camera shakes" or other movements on the images captured by the camera, and / or sensor-based image stabilization in which the image sensor is moved relative to a fixed lens or optical assembly. One or more of the cameras may include an autofocus function in which one or more lens elements (and / or sensors) are movable to focus an image on a sensor.The first camera 142 may include an image sensor having a pixel size between about 0.8 microns and about 1.4 microns. The second camera 144 may include an image sensor having a pixel size between about 1.6 microns and about 2.3 microns. The third camera 146 may include an image sensor having a pixel size between about 0.8 microns and about 1.4 microns.The first and second cameras 142, 144 may be aligned along the y-direction of the device (e.g., centered along a line extending in the y-direction). The orientation of the first camera 142 and the second camera 144 along the y-direction may facilitate capturing stereoscopic images and / or videos, such as three-dimensional images and / or videos. For example, the orientation of the cameras along the y-direction positions the cameras horizontally when the device 100 is maintained in landscape or horizontal orientation during imaging. In such cases, the horizontal orientation of the cameras 142, 144 facilitates the capture of three-dimensional or stereoscopic images or videos.Such images or videos may be displayed on a head mounted display or via other three-dimensional display technologies. In a head mounted display, images and / or videos captured with the stereoscopic functionality of the cameras 142, 144 may be displayed as three-dimensional media. In some cases, cameras 142, 144 may be used to capture three-dimensional scans of objects, and device 100 may generate three-dimensional virtual models of the objects for display with a head mounted display or other visualization technique.As used herein, the term "stereoscopic" may refer to a mode or operation of the device in which two or more cameras are used simultaneously or simultaneously to capture an image or video.The sensor array 141, together with the associated processors and software, may provide several features for image acquisition. For example, the sensor array 141 may be configured such that each time a user captures a still image, full resolution video clips of a certain duration are captured. As used herein, capturing full resolution images (e.g., video images or still images) may refer to capturing images using all or substantially all pixels of an image sensor or capturing images using the maximum resolution of the camera (regardless of whether the maximum resolution is limited by hardware or software).The recorded video clips can be associated with the still image. In some cases, users may select individual frames from the video clip as a representative still image associated with the video clip. In this way, when the user makes a snapshot of a scene, the camera captures a short video clip (e.g., 1 second, 2 seconds, or the like), and the user can accurately select the frame from the video to be used as a captured still image (in addition to simply displaying the video clip as video).The cameras of the sensor array 141 may also include or provide a high dynamic range (HDR) mode in which the camera captures images having a dynamic brightness range greater than that captured when the camera is not in the HDR mode. In some cases, the sensor array 141 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 brightness, hue, or other optical parameters in the scene, or the like. HDR images can be created by capturing multiple images with respectively different exposure or other image capture parameters and creating a composite image from the multiple captured images.The cameras of the sensor array 141 may also include software-based color balance correction. For example, if a flash (e.g., flash 148) is used during image capture, the cameras (and / or associated processing functions of the device 100) may adjust the image to compensate for differences in color temperature between the flash output and ambient lighting in the image. For example, if the background of an image has a different color temperature than the foreground subject (e.g., because the foreground subject is illuminated by flash light), the cameras may alter the background and / or foreground of the image to have a more consistent color temperature throughout the image.The sensor array 141 may also include an object detection mode or be configured to operate in a mode in which a user may select objects within a scene (and / or may automatically identify the device 100) to facilitate processing, displaying, or capturing those objects as compared to other portions of the scene. For example, a user may select (or the device 100 may automatically identify) the face of a person in a scene, and the device 100 may focus on the face of the person while selectively blurring the portions of the scene other than the face of the person. In particular, features such as the HDR mode and the object detection mode may be provided with a single camera (e.g., a single lens and a single sensor).The sensor array 141 may also include a depth sensing device 149 configured to estimate the distance between the device and a separate object or target. The depth detector 149 may estimate the distance between the device and a separate object or target using lasers and time-of-flight calculations or other components or techniques of depth investigation.The device 100 may also include a flash 148 (e.g., a rearward flash) configured to illuminate a scene to facilitate capturing images with the cameras of 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). In some cases, the light source(s) may be illuminated in a plurality of different illumination patterns, which together with a lens positioned over the light source(s) may create different illumination fields on a subject or scene. For example, a light source may be divided into a plurality of illuminable regions, wherein the illuminable regions may be positioned under different regions of the lens. When a first illumination pattern is activated (e.g., one or more central illuminable regions), the emitted light may pass through a first region of the lens (e.g., a central region) and create a first illumination field on a subject or scene (e.g., a relatively narrow light distribution corresponding to the field of view of a tele-lens). When a second illumination pattern is activated (e.g., one or more peripheral illuminable regions), the emitted light may pass through a second region of the lens (e.g., a peripheral region) and create a second illumination field on a subject or scene (e.g., a relatively wider light distribution corresponding to the field of view of a wide-angle lens). The flash 148 may be configured to generate two, three, or more different illumination fields, each corresponding to a field of view of one of the cameras of the sensor array 141. For example, the flash 148 may establish a first illumination field corresponding to (e.g., substantially equal to or greater than) a field of view of the first camera 142, a second illumination field corresponding to (e.g., substantially equal to or greater than) a field of view of the second camera 144, and a third illumination field corresponding to (e.g., substantially equal to or greater than) a field of view of the third camera 146.The sensor array 141 may also include a microphone 150. The microphone 150 may be acoustically connected to the exterior environment through a hole in the back cover of the device 100 (e.g., through the portion of the back cover defining the protrusion 151).FIGS. 1C and 1D show a further electronic device 140 in the form of a mobile telephone. The electronic device 140 may include many of the same or similar outward components as the electronic device 100. Accordingly, the descriptions and details of such components of FIGS. 1A-1B (e.g., displays, buttons, switches, housings, covers, charging ports, connection structures, etc.) apply equally to the corresponding components in FIGS. 1C and 1D.The device 140 may include a forward facing sensor region 113, which may generally correspond to the forward facing sensor region 111 in FIG. 1A. The forward-facing sensor region 113 may be positioned in an island-like region of the front of the device 140, and may be surrounded by a display region (e.g., a main display region) of the device 140. In some cases, as described herein, the forward sensor region 113 may be positioned in or defined by one or more display shaped holes. In such cases, the forward facing sensor region 113 may be bounded on all sides by active areas or regions of the display. In other words, the forward facing sensor region 113 may be completely surrounded by display active regions (e.g., an outer perimeter of the forward facing sensor region 113 may be surrounded by display active regions). In some cases, the forward-facing sensor region 113 includes or is defined by one or more masks or other visually opaque components or treatments defining openings for the sensors of the forward-facing sensor region 113. The forward sensor region 113 may include components such as an infrared lighting module (which may include a flood light emitter and a spot projector), an infrared image capture device, components of a proximity sensing system, and a forward camera.While the device 100 in FIG. 1B shows it including a sensor array 141 with three cameras, the device 140 shown in FIG. 1D includes a sensor array 134 (e.g., a rear facing sensor array in a rear facing region) that includes two cameras 138, 139. The sensor array 134 may be located in a sensor array region defined by a protrusion 137 in a back cover of the device 140. The protrusion 137 may define a raised sensor array region 163. Thus, the device back cover may define a first portion of a device back outer surface 140, and the protrusion 137 defines a second portion of the device back outer surface (which is raised or protrudes from the first portion of the device back outer surface). The protrusion 137 may have the same or similar construction as the protrusion 151 in FIG. 1B, although the protrusion 137 may have a different shape. For example, the protrusion 137 may be generally pill-shaped and may capture the two cameras in the y-direction of the device 140. The two cameras may be oriented along the y-direction.The orientation of the two cameras 138, 139 along the y-direction (e.g., centered on a line extending along the y-direction) may facilitate capturing stereoscopic images and / or videos, such as three-dimensional images and / or videos. For example, the orientation of the cameras along the y-direction positions the cameras horizontally when the device 140 is maintained in landscape or horizontal orientation during imaging. In such cases, the horizontal orientation of the cameras 138, 139 facilitates the capture of three-dimensional or stereoscopic images or videos. Such images or videos may be displayed on a head mounted display or via other three-dimensional display technologies. In a head mounted display, images and / or videos captured with the stereoscopic functionality of the cameras 138, 139 may be displayed as three-dimensional media. In some cases, cameras 138, 139 may be used to capture three-dimensional scans of objects, and device 140 may generate three-dimensional virtual models of the objects for display with a head-mounted display or other visualization techniques.The device 140 may also include, as part of the sensor array 134, one or more rearward-facing devices, which may include an ambient light sensor (ALS), a microphone port 135, and / or a depth sensing device configured to estimate the distance between the device 140 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. Thus, the sensor array 134 may include a camera array (which may include one or more cameras). The first camera 138 may include a super wide angle camera having a 12 megapixel sensor and a large field of view (e.g., 120° FOV) optical stack and a f / 2.4 aperture. The second camera 139 may include a wide-angle camera having a 48.8 megapixel sensor and an aperture of f / 1.6. In some cases, the sensor array 134 may include a tele-lens having a 12 megapixel triple optical zoom sensor and an f / 2.0 to f / 2.8 f-number (e.g., in addition to the first and second cameras 138, 139 or instead of one of the first or second cameras). As mentioned above, the cameras (or camera lenses) may be arranged along the y-direction of the device and positioned or adjusted in the protrusion 137.One or more of the cameras (e.g., cameras 138, 139) of sensor array 134 may also include optical image stabilization in which the lens is dynamically moved relative to a fixed structure within device 140 to reduce the effects of "shakes" on the 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 an autofocus function in which one or more lens elements (and / or sensors) are movable to focus an image on a sensor.The second camera 139 may include an image sensor having a pixel size between about 1.5 microns and about 2.0 microns, and the first camera 138 may include an image sensor having a pixel size between about 0.8 microns and about 1.4 microns. When a camera is provided with a tele-lens, it may include an image sensor having a pixel size between about 0.8 microns and about 1.4 microns.The sensor array 134 may also include a flash 136 (e.g., a rearward flash). The flash 136 may include a multi-segment LED, a single LED, or another light emitting component. The flash 136 may be positioned outside the protrusion 137 (e.g., in a portion of the rear cover 154 that does not include the protrusion 137). In some cases, the flash 136 is positioned at a point that is midway (in the y-direction) between the first camera 138 and the second camera 139 and offset in the x-direction from the cameras 138, 139. In other examples, the flash 136 may be positioned in line with and between the cameras 138, 139 (e.g., in the protrusion 137). In other words, in some cases, the first camera 138, flash 136, and second camera 139 may be centered on a line extending along the y-direction.The flash 136 and the microphone terminal 135 may be aligned with each other in the x-direction. For example, the flash 136 and the microphone port 135 may be centered on a line extending along the x-direction (which may be midway between the first camera 138 and the second camera 139).In some cases, the microphone terminal 135 is positioned on the protrusion 137, and the microphone module inside the device is located outside the area defining the protrusion 137. In such cases, an internal connection structure may direct the sound from the microphone connection 135 at the protrusion to the microphone module within the device.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 also apply to the sensor array, the individual cameras, and / or the flash of the device 140, and such details are not repeated herein to avoid redundancy.Referring to FIG. 1D, the device 140 may include a rear cover 154 connected to a housing 153 and defining at least a portion of the rear exterior surface of the device 140. The back cover 154 may be formed of or include an optically transmissive material. The optically transmissive material may be colored and in some cases may be colored glass material. The color of the optically transmissive material may be characterized by one or more color space coordinates, which in some cases may be a chroma value.The back cover 154 may include a substrate, also referred to herein as a back cover member, made of an optically transmissive glass material. The glass material may be silica-based material, such as an aluminosilicate glass, a borosilicate glass, an alkali metal aluminosilicate glass (e.g., a lithium aluminosilicate glass). Other examples of optically transmissive materials for the back cover 154 include, without limitation, sapphire, ceramic, glass ceramic, crystallizable glass materials, and plastic (e.g., polycarbonate). A glass ceramic material may be silica-based glass ceramic material, such as an aluminosilicate glass ceramic material or a borosilicate glass ceramic material. The glass or glass ceramic material can be chemically cured by ion exchange. The back cover 154 may be formed as a monolithic or one-piece sheet. The back cover 154 may also be formed as a composite of multiple layers of different materials, compositions, and other elements.In some examples, an outer surface of the back cover may have different textures in different regions of the cover. In some cases, the different textures may produce different optical effects, such as a matt effect in a first region of the outer surface and a glossy effect in a second region of the outer surface. The difference between the matt and gloss effect can be used to define graphics, words, images, logos or the like. For example, a visible logo may be defined by a glossy region (in the form of the logo) surrounded by a matt region.The back cover 154 may include a coating on the outer surface of the substrate, on the inner surface of the substrate, or on both. The coating may contribute to the appearance, such as the color, of the back cover 154. For example, a coating along an inner surface of the substrate may include one or more color layers. The colored layer may include a coloring agent such as a pigment or a dye and have a certain hue or a nearly neutral color. In some examples, the colored layer includes a polymeric binder that may be based on polyester, epoxy, urethane, or another suitable type of polymer or copolymer. Alternatively or additionally, the coating may include one or more opaque layers that are applied to (or otherwise positioned along) the inner surface of the substrate to provide a particular appearance to the back of the device 140. The opaque layer(s) may include a sheet, ink, dye, or combinations of these (or other) layers, materials, or the like, and in some cases may be optically dense. In some cases, the color of the coating along the inner surface of the substrate and the color of the substrate itself (e.g., the color of the optically transmissive material forming the back cover substrate) together determine the visible color of the back side of the device 140.In some cases, the back cover coating and / or the back cover material 154 itself has a color that substantially matches a color of the housing 153 (e.g., the exterior surfaces of the housing components and the interconnect structures). In this case, the coating of the back cover and the material of the back cover may have substantially the same colors, or may have different colors.A coating along an outer surface of the substrate may be a non-wiping (e.g., oleophobic) coating. The device 140 may include a wireless charging system, where the device 140 may be powered and / or its battery charged through inductive (or other electromagnetic) coupling between a charger (e.g., a wireless charging accessory) and a wireless charging system within the device 140. In such cases, the back cover 154 may be formed of a material that enables and / or facilitates wireless coupling between the charger and the wireless charging system (e.g., glass).The housing 153 may have a similar construction to the housing 104. For example, the housing 104 may be a multi-piece housing formed from or including multiple housing components (e.g., housing components 124, 125, 126, 127, 128, and 130 in FIGS. 1A-1B ) structurally interconnected via one or more intermediate members, such as hinge structures (e.g., 122- 1- 122- 6, FIGS. 1A-1B ). Together, the housing components and the connection structures may form a ribbon-like housing structure defining four side walls (and thus four outer surfaces) of the device 140. The four walls may include a top wall (e.g., proximate to the forward-facing sensor array 113), a bottom wall opposite the top wall (e.g., proximate to the port), a first side wall (e.g., a first face side visible in FIG. 1C ), and a second side wall opposite the first side wall (e.g., a second face side visible in FIG. 1D ). Thus, both the housing components and the connection structures define portions of the exterior side surfaces of the device 140.The housing components of the housing 153 may be formed of a conductive material (e.g., metal) and the interconnect structures may be formed of one or more polymeric materials (e.g., glass reinforced polymer). The connection structures may include two or more molded elements that may be made of different materials. For example, an inner molding member may be formed from a first material (e.g., a polymeric material) and an outer molding member may be formed from a second material different from the first (e.g., a different polymeric material). The materials may have different properties that may be selected based on the different functions of the inner and outer mold members. For example, the inner molded element may be configured to provide the main structural connection between the components of the housing, and may have a higher mechanical strength and / or toughness than the outer molded element. On the other hand, the outer molded member may be configured to have a certain appearance, surface area, chemical resistance, waterproof function or the like, and its composition may be selected to give preference to the mechanical strength among these functions. The connecting structures may be mechanically interlocked with the housing components to structurally connect the housing components and form a structural housing assembly.The housing components of the housing 153 may be formed from individual metal structures or from enclosure structures including multiple materials. As an example of a simple metal structure, the housing components may be formed of aluminum. As an example of a packaging structure, the package components may include a core portion formed from a first metal and a packaging portion formed from a second metal. The enclosure portion may define outer surfaces of the housing components. The outer surface defined by the enclosing portion may have a surface structure that creates a specific visual appearance and / or a specific haptics. For example, the surface texture may include a texture that creates diffuse reflections. The surface texture may be created by grinding, lapping, machining, ablation, blasting (e.g., sandblasting, pearlescent), etching (by mechanical etching, laser etching, chemical etching), or other suitable texturing methods. The exterior surface of the housing components may also include a coating, such as an applied coating. In some cases, the sheath portion is polished. The coating may be applied to the package components by plasma vapor deposition (PVD), chemical vapor deposition (CVD), or the like.In the case of cladding structures, the core portions of the housing components may be made of aluminum (e.g., an aluminum alloy) and the cladding portions may be made of titanium (e.g., a titanium alloy). In some cases, the core portions of the housing components are made of aluminum and the cladding portions are made of stainless steel. The sheath portions may have an average thickness between about 0.1 mm and about 1.0 mm. The aluminum of the housing may include reused aluminum (e.g., up to 70% reused aluminum, up to 85% reused aluminum, or another value).The device 140 may also include one or more buttons (e.g., buttons 152 and 155 in FIG. 1C and buttons 156 and 157 in FIG. 1D ), switches, and / or other physical input systems. Such input systems may be used to control the power state (e.g., key 152), control applications (e.g., key 155), change speaker volume (e.g., key 156), switch between "ring" and "mute" modes (e.g., key 157), and the like. The buttons 152, 156, 155, and 157 may include strain sensing systems that sense inputs to the buttons based on a sensed strain. The buttons 152, 156, 155, and 157 may also be associated with haptic actuation systems that generate a tactile output in response to sensing a load that satisfies a particular condition. For example, upon sensing a strain or force that satisfies a condition (and / or an electrical parameter indicative of a strain that satisfies the condition), a haptic actuator system may apply a force to a button to produce a tactile output (e.g., similar to a "click"). This tactile output or response may provide tactile feedback to the user to indicate that the input has been detected by the device.The buttons 152, 156, 155, and 157 may be or correspond to embodiments of the buttons 116, 118, 120, and 121 described above, and the description of these buttons applies equally to the buttons 152, 156, 155, and 157. In some cases, one or more of the buttons 152, 156, 155, and 157 may use switch elements, such as hinged dome switches, to detect keystrokes. Such dome switches may be used in place of strain-based or other non-binary force sensors. However, in some cases, in addition to the strain-based or non-binary force sensors, dome switches or other hinged or tactile switches may also be used in a particular button. In such cases, the key may facilitate the detection of binary or instantaneous inputs while detecting the magnitude of a force applied to the key. In such cases, the device 100 may perform various operations in response to detecting the binary or current input and in response to detecting a force that satisfies a condition. In particular, a user can provide a partial actuation of the button, in which a force is applied, but the switch is not folded in. The device 100 may perform one or more operations in response to detecting partial actuation of the button (e.g., in response to detecting a force that satisfies a condition). A user may then provide a full button actuation in which the force is increased until the switch is actuated or another input is registered (e.g., the dome switch folds together). The device 100 may perform one or more additional operations in response to detecting the switch actuation. As a non-limiting example, the button may be used to provide input to the device 100 when the device 100 is operating in an image capture mode. In such cases, a partial operation may cause the apparatus 100 to initiate a focusing operation or disable an exposure setting for image capturing. When the full actuation is detected (e.g., when the binary or button is actuated), the device 100 may capture an image with one of the built-in cameras. In response to the partial and / or full actuation of the button, other functions may also be initiated, including other image capture functions or other device or application functions. For example, a partial actuator may initiate scroll (e.g., browsing through entries in a displayed list) and a full actuator may initiate selection of a selected entry in the list. In some cases, the key 155 of the device 140 includes both a dome switch (or other binary or momentary switch) and a stretch-based sensing system. In some cases, one or more other buttons of device 140 include both a dome switch (or other binary or momentary switch) and a strain-based sensing system.In some cases, one or more of the buttons 152, 156, 155, and 157 may use touch sensing systems, such as capacitive touch sensing systems, to sense inputs. For example, the tactile element of a button (e.g., the movable component that a user presses to actuate the button or provide input) may include a touch sensitive element positioned thereon. A key equipped with a touch-sensitive element may sense various types of touch-based inputs, including static touch inputs (e.g., a finger touching the touch-sensitive surface of the key), dynamic touch inputs (e.g., a finger sliding over the touch-sensitive surface of the key, also referred to as gesture or stroke inputs), or the like.In some cases, the button 155 may include a touch-sensitive element 161 to sense such touch-based inputs. The device 140 may perform various operations in response to sensing touch-based inputs. Continuing the above example: When the device 140 is operating in an image capture mode, a static touch input may initiate a focus or exposure lock, while a dynamic or swiping touch input may initiate a zoom operation (e.g., swiping in one direction may initiate a zoom-in operation and swiping in the opposite direction may initiate a zoom-out operation).In some cases, the touch-sensitive element 161 may detect the location of an input on the button 155 during a key actuation, and the device may perform various actions based on the location of the touch. For example, when the button 155 is actuated with an input at a first location on the button 155 (e.g., at an end of the button 155 as detected by the touch-sensitive element 161), the device may perform a first action (e.g., a magnifying operation), and when the button 155 is actuated with a press input at a second location on the button 155 (e.g., at an opposite end of the button 155 as detected by the touch-sensitive element 161), the device may perform a second action different from the first action (e.g., a reducing operation).In some cases, the touch sensing element 161 may detect whether an input to the key 155 is made with one finger or with two fingers, and may then perform different operations. For example, when the single finger key 155 is actuated (as detected by the touch-sensitive element 161), the device may perform a first action (e.g., capture a single image), and when the multi-finger key 155 is actuated (as initiated by the touch-sensitive element 161), the device may perform a second action different from the first action (e.g., capture a sequence of images for the duration of the actuation or initiate a video capture operation).Other sensing techniques may also be used to detect inputs to the keys. In some cases, a switch or other input device is used instead of one or more buttons.As mentioned above, the button 155 may be force and / or pressure sensitive (e.g., capable of detecting variable force inputs) and may generate multiple controls or outputs based on the amount of force input, the presence of a touch, the location of the touch, and the movement of the touch (gesture). The particular operation initiated in response to a particular key input may vary in accordance with (e.g., proportional to) the applied force. In some cases, a force-based input without a sensed touch input at touch-sensitive element 161 may suppress an action or be ignored by the device. The button 155 may also be coupled to one or more other buttons for designated operations or commands (e.g., the device may perform certain operations in response to detecting simultaneous inputs to multiple buttons or certain sequences of inputs to multiple buttons).As described in several examples above, the button 155 may be used to initiate or control image capture functions and operations. For example, a light touch of the button 155 (e.g., a sensed touch input without force or with a force that satisfies a first force state corresponding to a light deflection of the button) may initiate a sharpness and exposure measurement operation, and a larger force or deflection of the button (e.g., that satisfies a second force state) may initiate an image or video capture operation. Additionally, different haptic outputs may be generated in response to detecting different inputs at the button 155 and / or in response to the different operations initiated by the button inputs.Other examples of image manipulations and / or camera function controls that may be initiated by inputs to the key 155 (force and / or touch inputs) include increasing or decreasing in response to swiping inputs on the key surface in different directions; increasing or decreasing volume in response to inputs on the key input surface in different directions; capturing a single image or a series of multiple images in response to different force inputs (e.g., a single light press image, multiple stronger press images). In such cases, different haptic outputs may be generated in response to detecting different inputs to the button 155 and / or in response to the different operations initiated by the button inputs.The button 155 may also result in the device performing other functions that are either linked to the operation of the device or set in response to operation of a particular application or mode of use of the phone. For example, inputs on button 155 may cause the device to perform operations such as: selecting one or more alarm suppression modes (muting); checking the purchase or checking of the application command; controlling timer commands including clock-related operations; providing inputs to games such as throttle control or other continuously variable inputs; initiating a hard and / or soft reset of the device; initiating user programmable operations; and starting or ending applications. In some cases, the particular function of the key may be programmed or selected by the user. For example, a user may select which functions or operations are initiated in response to various force inputs, gesture inputs, and touch inputs. The user may also specify different input schemes for different modes of the device. For example, the user may associate force, touch, and gesture inputs with a first set of functions when the device is operating in a first mode (e.g., when a first application is executed), and may associate force, touch, and gesture inputs with a second set of functions when the device is operating in a second mode (e.g., when a second application is executed).In some cases, the function of the button 155 may change based on the orientation of the device. For example, the force, touch, and gesture inputs may be associated with a first set of functions when the device is maintained vertical or in portrait format, and the force, touch, and gesture inputs may be associated with a second set of functions when the device is maintained horizontal or in landscape format.".The key 155 may also be used to initiate stereoscopic image or video capture. In some cases, selection of a stereoscopic image capture mode (or switching between stereoscopic and non-stereoscopic image modes) may be controlled by operation of the button 155 or other inputs of the device (e.g., other buttons, touch screen inputs, etc.). In some cases, the ability to select (or transition between a stereoscopic image mode and other image modes) a stereoscopic image mode with the key 155 may depend on the orientation of the device.FIG. 2 shows an exploded view of an example electronic device. In particular, FIG. 2 shows an exploded view of a device 200 showing various components of the device 200 and example arrangements and configurations of the components. The apparatus 200 may be an embodiment of the apparatus 100, and the description of the various components and elements of the apparatus 100 of FIGS. 1A and 1B may also be applicable to the apparatus 200 illustrated in FIG. 2. Redundant description of some components will not be repeated here for clarity.As shown in FIG. 2, the device 200 includes a cover 202 (e.g., a front cover) that may be formed from or include a transparent or optically transmissive material. In some cases, the cover 202 is formed from or includes a glass material and may therefore be referred to as a glass cover element. The glass material may be silica-based glass material, aluminosilicate glass, borosilicate glass, alkali metal aluminosilicate glass (e.g., lithium aluminosilicate glass), or chemically strengthened glass. Other example materials for the cover 202 include, without limitation, sapphire, ceramic, glass ceramic, crystallizable glass materials, and plastic (e.g., polycarbonate). The cover 202 may be formed as a monolithic or one-piece sheet. The cover 202 may also be formed as a composite of multiple layers of different materials, compositions, and other elements. In this example, the cover 202 may be formed of a 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 the strength or other properties of the cover 202. A glass ceramic material may be silica-based glass ceramic material, such as an aluminosilicate glass ceramic material or a borosilicate glass ceramic material. The glass ceramic material can be chemically hardened by ion exchange. In some cases, the cover 202 may include a sheet of chemically tempered glass or glass ceramic with one or more coatings including an anti-reflective (AR) coating, an oleophobic coating, or another type of coating or optical treatment. In some cases, the cover 202 includes a sheet of material 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 about 0.60 mm or less. The cover 202 may be chemically solidified using an ion exchange process to form a compressive stress layer along the outer surfaces of the cover 202.The cover 202 extends substantially over the entire front surface of the device and may be positioned in an opening bounded by a housing structure 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 structure 210 without an intervening component being present between the edges of the cover 202 and the respective flanges of the housing structure 210. This configuration may allow an impact or force applied to the housing structure 210 to be transmitted to the cover 202 without transmitting shear stresses directly via the display 203 or the frame 204.As shown in FIG. 2, the display 203 is connected to an inner surface of the cover 202. The display 203 may include an organic light emitting diode (OLED) display that measures 6.86 inches or 6.27 inches from corner to corner. The perimeter or non-active area of the display 203 may be reduced to allow very thin edges of the device around the active area of the display 203. In some cases, the display 203 allows edge regions of 1.5 mm or less. In some cases, the display 203 allows edge regions of 1 mm or less. In an example implementation, the edge region is about 0.9 mm. The display 203 may have a relatively high pixel density of about 460 pixels per inch (PPI) or more. The display 203 may use a back plate of low temperature polycrystalline silicone (LTPS) or low temperature polycrystalline oxide (LTPO).The display 203 may include an on-cell (integrated touch sensing system). For example, an array of electrodes (or other touch sensitive components) integrated into the OLED display may be operated in time and / or frequency division multiplexing to provide both a display and touch sensitivity function. The electrodes may be configured to sense the location of a touch, gesture input, multi-touch input, or other types of touch inputs along the outer 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-sensitive and / or force-sensing components or layers positioned between the display 203 and the cover 202.The display 203, also referred to as a display stack, may include the function "Ways-on-Display" (AOD). For example, the display 203 may be configured to display designated regions or subsets of pixels 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 mode or idle. This may display the time, date, battery status, latest notifications, and other graphical content in a lower power mode or idle state. This graphical content may be referred to as persistent or constantly active graphical output. Although a certain battery current can be consumed in the display of continuous or continuously switched-on graphics, the energy consumption is usually lower than in the case of normal or full-load operation of the display 203. This function may be activated by operating only a subset of the display pixels and / or at a reduced resolution to reduce the power consumption of the display 203.The display 203 may include multiple layers, including touch sensitive layers or components, optional force sensing layers or components, display layers, and the like. The display 203 may define a graphically active region in which graphical outputs may be displayed. In some cases, portions of the display 203 may include graphically inactive regions, such as portions of the display layers that do not include active display components (e.g., pixels) or are otherwise not configured to display graphical outputs. In some cases, graphically inactive regions may be located along the peripheral edges or other edges of the display stack 203.As shown in FIG. 2, the device 200 may also include a shaped frame member 204, also referred to simply as a shaped frame 204, positioned below the cover 202 and extending around at least an outer perimeter of the display 203. The molded frame 204 may at least partially encapsulate the edges of the display 203 and define a structural feature that provides strength and rigidity to the cover 202 and the display 203 and serves as a mounting structure to connect the cover 202 to a housing (e.g., the housing structure 210).The molded frame 204 may be created by applying a moldable material to a sub-assembly that includes the cover 202, the display 203, and optionally other structural components. The subassembly may be positioned in a mold or other device and a flowable material may be introduced into a mold cavity such that the material flows around the edges of the display 203, contacts an inner surface of the cover 202, and optionally contacts other components of the subassembly (e.g., a back plate covering the display 203 and serving as a shield and / or support structure for the display and cover). The flowable material then cures to form the shaped frame 204. As a result of the cure, the molded frame 204 (e.g., an over molded frame) is connected (e.g., by mechanical locking and / or bonding) to the display 203, the cover 202, and other components of the subassembly.The molded frame 204 may be attached to a bottom or inner surface of the cover 202. A portion of the molded frame 204 may extend below the display 203 and attach the cover 202 to the housing structure 210. Because the display 203 is attached to a bottom or inner surface of the cover 202, the molded frame 204 may also be referred to as attaching both the display 203 and the cover 202 to the housing structure 210.The cover 202, the display stack 203, and the molded frame 204 may be part of a front cover assembly 201 of the device 200. The front cover assembly 201 (and more specifically, the cover 202 of the front cover assembly 201) may form a front exterior surface of the device. The cover 202 may have an inner surface opposite the outer surface.The front cover assembly 201 may be assembled as a sub-assembly, which may then be attached to a housing component. For example, as described herein, the display 203 may be attached to the cover 202 (e.g., by a transparent adhesive), and the molded frame 204 may be molded around a perimeter of the display stack 203. The front cover assembly 201 may then be attached to a housing component of the device 200 by attaching and adhering the molded frame 204 to a ledge defined by the housing component.The apparatus 200 also includes a speaker module 250 configured for sound output via a speaker port. The speaker port may be positioned in and / or at least partially bounded by a recess of the cover 202. As described herein, a portion of the trim may be at least partially positioned within the depression to facilitate sound output while inhibiting debris, liquid, or other materials or contaminants from entering the device 200. Output from the speaker module 250 may be through an acoustic passageway or path defined at least in part by the speaker module 250 itself and the piece. In some cases, a portion of the acoustic path (e.g., between the speaker module 250 and the patch) is defined by the housing structure 210 and / or a molded material connected to the housing structure 210. For example, a molded material (e.g., a fiber reinforced polymer) may be molded against a metallic portion of the housing portion 210 (e.g., the housing component 213) described herein. The molded material may also form one or more intermediate members, such as interconnect structures, that also structurally connect package components together (e.g., interconnect structures 218). A port or passage (e.g., a tubular tunnel) may be defined by the molded material to acoustically couple the speaker module 250 to the piece and / or the depression in general, thereby conducting the sound from the speaker module 250 to the exterior of the device 200.As shown in FIG. 2, the device 200 also includes one or more cameras, optical emitters, and / or sensor elements configured to transmit, receive, or otherwise operate signals along the front surface of the device. In this example, the device 200 includes a front camera 206 having a high resolution camera sensor. The front camera 206 may include a sensor with a resolution of 12 megapixels and optical elements that provide a field of view of 85° and an aperture of f / 1.9. The front camera 206 may include an autofocus function in which one or more of the lens elements move (e.g., up to about 100 micrometers perpendicular to the cover) to focus an image on the camera sensor. In some cases, the forward autofocus camera may provide a continuous autofocus function during video capture. The apparatus 200 also includes a face detection optical system 252 that includes an infrared light projector (for projecting light) and an infrared light sensor configured to sense an array of depth points or regions along the user's face. The array of depth points may be characterized as a unique signature or bioidentification that may be used to identify and / or authenticate the user and unlock the device 200 (and / or authorize functions on the device 200, such as purchase software apps or use payment functions provided by the device 200).The device 200 may also include one or more other sensors or components. For example, the apparatus 200 may include an illumination element for the front camera 206 that provides flash light or illumination for the front camera 206. The apparatus 200 may also include an ambient light sensor (ALS) that serves to sense the ambient light conditions to adjust the exposure aspects of the front camera 206 and / or control the operation of the display. The device 200 may also include a proximity sensing system 253 to sense the proximity of a user or other object to the device 200. In some cases, as described herein, the proximity sensing system 253 senses proximity to other objects via an active region of the display. The proximity sensing system 253 and the optical face sensing system 252 may be integrated into a common module. In some cases, the information of both the proximity sensing system and the ambient light sensor is used to determine the ambient light conditions and / or the proximity of objects to the device 200. For example, information from the proximity sensing system may be used to determine whether a low ambient illumination sensed by the ambient light sensor is due to a low ambient illumination or an object that locally or temporarily covers the ambient light sensor (e.g., a finger making a touch input or a palm on an input). The information of both sensing systems may be used to distinguish between potentially ambiguous states and generally improve the accuracy with which the device may sense certain states.The display 203 may include one or more holes extending through the display to receive the front camera 206, the face detection system 252, the proximity detection system 253, and optionally other forward facing sensors or other components. In some cases, the display 203 includes two holes, including a first hole for the front camera 206 and a second hole for the face detection system 252 and the proximity detection system 253. In some cases, the display 203 includes only one hole (e.g., a single hole shared by the front camera 206 and the face detection system 252). In some cases, the display 203 includes three holes (e.g., a first hole for the front camera 206, a second hole for a transmitter of the face detection system 252, and optionally for the proximity detection system 253, and a third hole for a receiver of the face detection system 252).FIG. 2 also illustrates one or more cameras, optical transmitters, and / or sensor elements configured to transmit signals, receive signals, or otherwise operate along the rear surface of the device. As shown in FIG. 2, these elements may be integrated into a sensor array 260. In this example, the sensor array 260 (or camera array) includes a first camera 263 having a 12 megapixel sensor and a 3x optical zoom (or 5x optical zoom) telelens and a f / 2.8 aperture. The sensor array 260 also includes a second camera 262 having a 48.8 megapixel sensor with a wide angle lens with an f / 1.7 f / 1.7 f-number. The sensor array 260 may also include a third camera 261 having a 48 megapixel sensor and a super wide angle camera with a large field of view (e.g., 120° FOV) and a f / 2.2 aperture. The first, second, and third cameras may include lens or sensor-based image stabilization.The sensor array 260 also includes a light source that can be used as a flash for photography or as an auxiliary light source (e.g., flash light). In some cases, the sensor array 260 also includes a microphone, an ambient light sensor, and other sensors suitable for measuring along the rear surface of the device 200.The sensor array 260 may also include a depth detector 281 (which may correspond to or be an embodiment of the depth detector 149, FIG. 1B, or other depth detector described herein) capable of estimating a distance to objects positioned behind the device 200. The depth sensing device 281 may include an optical sensor that uses the time of flight or other optical effect to measure a distance between the device 200 and an external object. The depth sensing device 281 may include one or more optical emitters suitable for emitting one or more light beams that may be used to estimate the distance. In some cases, the one or more light beams are coherent light beams having substantially a uniform wavelength / frequency. A coherent light source may facilitate depth measurements using time of flight, phase shift, or other optical effects. In some cases, the depth sensing device 281 uses an acoustic output, a radio output, or other type of output that may be used to measure the distance between the device 200 and one or more external objects. The depth detector 281 may be positioned proximate a window (e.g., a region of the back cover 272 or another component covering the components of the sensor array 260) through which the depth detector 281 may transmit and / or receive signals (e.g., laser light, infrared light, visible light, etc.).As shown in FIG. 2, cameras 261, 262, 263 may be aligned with covers 266, 267, and 268, respectively. The covers 266, 267, 268 may be formed of a glass or sapphire material and provide a clear (e.g., transparent or optically transmissive) window through which the cameras 261, 262, 263 may capture a photographic image. In other cases, the covers 266, 267, 268 are optical lenses that filter, magnify, or otherwise condition the light received from the respective camera 261, 262, 263. The other sensing or transmitting elements of the sensor array 260 may transmit and / or receive signals through a region of the back cover 272 or through a separate cover coupled to the back cover 272. As shown in FIG. 2, the covers 266, 267, 268 may extend beyond the outer surface of the cover 272 and form a recess along the inner surface of the cover 272 such that the lenses or other elements of the cameras 261, 262, 263 may protrude into the respective recesses. In this manner, the device 200 may capture a larger lens or other elements of the cameras 261, 262, 263 than would be possible if the recess were not provided. In some cases, trim assemblies 269 may be connected to the rear cover 272 and support the covers 266, 267, 268.A battery 230 is also included in the device 200. 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 housed within a rigid metal shell (or flexible film forming a pouch). The battery 230 may include a rolled electrode configuration, sometimes referred to as a "jelly roll" or a folded or stacked electrode configuration. In a rigid metal shell, the shell may include a two-part housing, in which the two parts define an interior volume enclosing the electrodes and an electrolyte (e.g., a liquid) or other suitable battery formulation. The first and second portions of the shell may be joined together by welding, soldering, gluing, or other suitable fastening technique. In some cases, the battery can includes one or more end-to-end terminals to enable conductive connection to an internal electrode (e.g., a positive electrode). In some cases, the battery case is conductively connected to an internal electrode (e.g., a negative electrode), and the battery case itself serves as a negative or "common" electrode for the circuitry of the device 200.The battery 230 may be secured to the device 200 (e.g., to a chassis portion 219, which may also be referred to as a middle chassis portion or simply a chassis) using one or more adhesives and / or other attachment techniques. In one example, the battery 230 may be secured to the chassis portion 219 or other structure of the device 200 with an electrically releasable adhesive (e.g., an adhesive whose adhesive strength may be selectively decreased in response to an electrical charge). In such cases, the adhesive may include conductive terminals that are in conductive contact with the electrically releasable adhesive. When the electrically releasable adhesive (EDA) is supplied with electrical power (e.g., by a user during a battery change), the adhesive force of the adhesive may be reduced until the battery disengages from the adhesive and / or the chassis portion 219 or until the adhesive force is so low that the battery may be easily removed by a user (e.g., without damaging the battery or other components of the device).The battery 230 may be charged via a port 232 (e.g., via a charging cord inserted into the port 232 through a charging port 226) and / or via a wireless charging system 240. The battery 230 may be connected to the charging port 232 and / or the wireless charging system 240 via control circuitry that controls the energy provided to the battery and the energy provided from 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 port 232 may be or include a connector port.The wireless charging system 240 may include a coil that inductively connects to an output or transmit 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 wireless charging system 240 includes a coil assembly 242 that includes multiple turns of conductive wire or other lead configured to generate a (charging) current in response to placement in an induction electromagnetic charging field generated by a separate wireless charging device or accessory. The coil assembly 242 also includes or is associated with an array of circular or radially arranged magnetic elements. The magnetic elements may help locate the device 200 with respect to a separate wireless charging device or other accessory. In some implementations, the array of magnets also helps radially locate, align, or "clock" the device 200 with respect to the separate wireless charging device or other accessory. For example, the array of magnets may include a plurality of magnetic elements of alternating magnetic polarity arranged in a radial pattern. The magnetic elements may be arranged to provide magnetic coupling with the separate charger in a particular orientation or a series of discrete orientations to aid in positioning the device 200 relative to the separate charger or other accessories. This functionality may be referred to as self-aligning or self-locating wireless charging. As shown in FIG. 2, the device 200 also includes a magnetic reference point 244 to locate the location of the separate wireless charging device or accessory. In one example, the magnetic reference point 244 is adapted to magnetically connect to a separate wireless charging device or other accessory. By coupling to the separate wireless charging device / accessory, the rotational orientation of the device 200 and the separate wireless charging device / accessory may be maintained with respect to an absolute or single position. The magnetic coupling of the charging device / accessory to the rear surface of the device 200 also enables the charging device or other accessory to be more securely connected 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 an NFC antenna capable of receiving and / or transmitting wireless communications between the device 200 and the wireless charger or other accessory. In some cases, the device 200 is capable of performing wireless communication to detect or detect the presence of the wireless charger or other accessories without using a dedicated NFC antenna. The communication may also include information about the state of the device, the state of charge of the battery 230 and / or control signals for increasing the charging process, for reducing the charging process, for starting the charging process and / or for ending the charging process for a wireless charging process.The wireless charging system 240 may also include one or more graphite layers (or other thermally conductive layers) that improve the thermal performance of the wireless charging system 240 and / or the device itself. For example, the graphite layers on the wireless charging system 240 may dissipate and / or distribute the heat of the coil during the charging process. In some cases, the graphite layers may absorb and transfer heat from other components, such as from the battery 230.The apparatus 200 may also include a speaker system 224. The speaker system 224 may be positioned in the device 200 such that a corresponding port 225 is aligned with or proximate to an audio output of the speaker system 224. Accordingly, the sound output by the loudspeaker system 224 exits the housing structure 210 via the respective connection 225. The speaker system 224 may include a speaker positioned in a housing defining a speaker volume (e.g., an empty space in front of or behind a speaker diaphragm). The volume of the speaker may be used to tune the audio output of the speaker and optionally mitigate destructive interference of the sound produced by the speaker.The device 200 may also include a haptic actuator 222. The haptic actuator 222 may include a movable mass and an actuation system 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 cooperate to establish movement. The magnets may be made of or include reused magnetic material.When the coil(s) is / are energized, the coil(s) may / are capable of moving the mass, causing a force to be applied to the device 200. The movement of the mass may be configured to cause vibration, momentum, knock, or other tactile output that may be detected via an outer surface of the device 200. The haptic actuator 222 may be configured to move the mass linearly, but other movements (e.g., rotational) are also conceivable. The mass may move in the x-direction. Other haptic actuators may be used instead of or in addition to the haptic actuator 222.In some cases, the haptic actuator 222 is configured to generate a first haptic output in response to the device detecting that a force input applied to a button (e.g., a button having a strain or other force sensing element) satisfies a force threshold, and is also configured to generate a second haptic output in response to a notification event (e.g., an event associated with a haptic notification or upon occurrence of which the device generates a haptic output). Thus, the same haptic actuator 222 may be used to generate haptics for notifications, simulate keystrokes, or otherwise indicate that an input satisfying a force threshold has been received.The apparatus 200 also includes a circuit board assembly 220. The circuit board assembly 220 may include a substrate as well as processors, memory, and other circuit elements connected to the substrate. The circuit board assembly 220 may include multiple circuit boards stacked and interconnected to maximize the range available for electronic components and circuitry in a compact form factor. The circuit board assembly 220 may include provisions for a subscriber identity module (SIM). The circuit board assembly 220 may include electrical contact assemblies and / or a SIM slot assembly that receives a physical SIM card, and / or the circuit board assembly 220 may include provisions for an electronic SIM card. When using an electronic SIM card, the device 200 may manage without a SIM drawer (e.g., the device may not include any openings, slots, slots, doors, or other mechanical means for inserting or otherwise accessing a SIM card). The circuit board assembly 220 may be fully or partially encapsulated to reduce the risk of damage from water or other fluids ingress. As described herein, thermal bridges may be attached to the circuit board assembly 220 to assist in the transfer of heat from the circuit board assembly 220 to other regions or components of the device 200 (e.g., to the chassis portion 219). The thermal bridges may include graphite-wrapped foams or graphite-coated loops, where the loop or foam structure maintains the graphite (providing thermal conductivity) in contact with the circuit board assembly 220 and the other components.The circuit board assembly 220 may also include wireless communication circuitry operatively coupled to and / or otherwise using housing components 211, 212, 213, 214, 215 or 216 (or portions thereof) as radiation elements to provide wireless communication. The circuit board assembly 220 may also include components such as accelerometers, gyroscopes, circuitry for near field communication and / or antennas, compass, and the like. In some implementations, the circuit board assembly 220 may include a magnetometer suitable for sensing and / or locating an accessory. For example, the magnetometer may be capable of detecting a magnetic (or non-magnetic) signal generated by an accessory of the device 200 or another device. The output of the magnetometer may include a directional output that may be used to display a directional indication or other navigation guidance on the display 203 to guide the user to a location of the accessory or other device.The apparatus 200 may also include one or more pressure transducers capable of sensing changes in external pressure to determine changes in elevation. The pressure sensors may be provided with external terminals and / or positioned in a watertight inner volume of the casing treatment 210. The output of the pressure sensors may be used to track the steps being traversed, the location (e.g., a floor) of a multi-level structure, the movements performed during activity to estimate physical effort or calorie consumption, or other relative movements of the device 200. A pressure transducer may be positioned in a module 237 that communicates with the external environment via ports 225 in the housing structure 210. The module 237 may include additional components, such as a microphone and barometric vent (e.g., to allow pressure equalization between the interior of the device 200 and the external environment while inhibiting water ingress).The circuit board assembly 220 may also include global positioning 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)) to estimate an absolute location of the device 200. In some implementations, the GPS electronics may use two frequency bands. For example, GPS electronics may use L 1(L 1C), L 2(L 2C), L 5, L1+L 5, and other GPS signal bands to estimate the location of device 200.As shown in FIG. 2, the housing may include a cover 272 (e.g., a back cover 272) that defines substantially the entire back surface of the device 200. The back cover 272, the front cover 202, and the housing structure 210 may at least partially form a shell of the device 200, which may define an interior volume in which components of the device 200 are positioned. The cover 272 may be formed of or include a transparent or optically transmissive material. For example, the cover 272 may include a substrate made of or based on a glass material or other suitable material (e.g., silica-based glass material, aluminosilicate glass, borosilicate glass, alkali metal aluminosilicate glass, chemically tempered glass, sapphire, ceramic, glass ceramic, crystallizable glass materials, or plastic). A glass ceramic material may be silica-based glass ceramic material, such as an aluminosilicate glass ceramic material or a borosilicate glass ceramic material. The glass ceramic material can be chemically hardened by ion exchange. The substrate may have portions less than 1 mm thick. In some cases, the substrate has portions less than 0.80 mm. In some cases, the substrate has portions that are about 0.60 mm or less. The cover 272 may have a uniform thickness, or in some cases a thickened or raised portion surrounding the camera covers 266, 267, 268. The cover 272 may be machined (e.g., ground) to a final shape before being polished and / or textured to provide the desired surface. The texture may be configured to provide a matt appearance while being resistant to the accumulation of skin, lint or other debris.The cover 272 may be formed of a colored optically transmissive material and may include a coating along an inner surface of the cover 272 that, along with the color (or lack of color) of the optically transmissive material, determines the color of the back of the device. For example, a coating along an inner surface of the cover may include one or more color layers. The colored layer may include a coloring agent such as a pigment or a dye and have a certain hue or a nearly neutral color. Alternatively or additionally, the coating may include one or more opaque layers that are applied to (or otherwise positioned along) the inner surface of the substrate to provide a particular appearance to the back of the device. The opaque layer(s) may include a sheet, ink, dye, or combinations of these (or other) layers, materials, or the like, and in some cases may be optically dense.The cover 272 may be part of a rear cover assembly 273. The rear cover assembly 273 may be connected to the housing structure 210. In some cases, the rear cover assembly 273 includes components such as the camera covers 266, 267, 268, the trim assemblies (e.g., trim assemblies 269), components of a wireless charging system, structural components (e.g., frames), fastening clips, and / or other components, systems, subsystems, and / or materials. The rear cover assembly 273 may be removable from the housing structure 210 to facilitate repair and / or replacement of the rear cover assembly 273 and / or internal components of the device 200.The rear cover assembly 273 may include a bracket 283 connected to an inner surface of the rear cover 272. The support plate 283 may be bonded to the inner surface of the back cover by an adhesive.The support plate 283 may be made of metal and form a structural molding surface for components of the back cover 273 (e.g., a wireless charging system). In some cases, the trim strips 269 are secured to the support plate, such as by welding, brazing, brazing, or other suitable fasteners. The support plate 283 may be a unitary metal structure that extends substantially across the entire inner surface of the back cover 272 (e.g., including a region for wireless chargers and a region for the rear-facing camera). In other examples, the support plate 283 may be comprised of multiple separate metal components 282- 1, 282- 2 (e.g., a first metal component 282- 1 near the wireless charger region and a second metal component 282- 2 in the rear camera region). If the support plate 283 is formed from a plurality of separate metal components 282, the metal components may be made of the same metal (e.g., both of aluminum or both of stainless steel) or different materials (e.g., the first metal component 282- 1 may be made of aluminum and the second metal component 282- 2 may be made of stainless steel). The first and second metallic components 282- 1, 282- 1 may be joined together. For example, the second metallic component 282- 2 may have tabs that overlap and are welded, soldered, brazed, or otherwise joined to the first metallic component 282- 1. The attachment of the first and second metal components 282- 1, 282- 2 may conductively connect the components to each other and also increase the structural rigidity and / or integrity of the support plate 283 and the rear cover assembly 273.The support plate 283 may be thermally coupled to other components of the device, such as via thermal bridges, as described herein. Examples of thermal bridges include graphite wrapped foam (e.g., a graphite layer wrapped around a foam or other compliant material), conductive loops (e.g., a graphite or other thermally conductive layer on a loop structure formed by a substrate), direct metal-to-metal contacts, thermal paste or heat gel, or the like. Thermal bridges may thermally connect the support plate 283 to components such as the circuit board assembly 220, the battery 230, and the sensor array 260. The support plate 283 may be formed of a thermally conductive material such as a metal (e.g., aluminum), and the heat of the other components may be transferred to the support plate 283. The support plate 283 may therefore function as a heat sink and generally spread the heat throughout the support plate 283, which may contribute to reducing the peak temperatures of the device or components.The rear cover assembly 273 may also include attachment features such as tabs or clips that engage complementary attachment features of another component (e.g., a housing segment 217, which may be a sub-assembly) to connect the rear cover assembly 273 to the housing segment 217. The attachment features may be integral with the support plate 283 (e.g., the support plate and the attachment features may be made of a single piece of metal).Similar to the description of the cover 202, the cover 272 may be at least partially positioned within an opening defined in the housing structure 210. The edges or sides of the cover 272 may also be surrounded by a protective flange or lip of the housing structure 210 without an intervening component being located between the edges of the cover 272 and the respective flanges of the housing structure 210. The cover 272 is typically chemically consolidated by an ion exchange process to compress a layer with compressive stress along the outer surfaces of the cover 272.The housing structure 210 may include a housing segment 217 (e.g., a middle housing segment 217) that includes the housing components 211 and 214, and a chassis portion 219 (e.g., a metal plate-like structure extending between the housing components 211 and 214, also referred to simply as chassis 219). The housing component 211 may define a first wall portion defining at least a portion of a first lateral exterior surface of the device, and the housing component 214 may define a second wall portion defining at least a portion of a second lateral exterior surface of the device opposite the first lateral exterior surface. The chassis 219 extending between the first wall portion and the second wall portion (defined by the housing components 211, 214) may define a component mounting structure of the device 200. For example, as described herein, components such as the circuit board assembly 220, the battery 230, the sensor array 260, the speaker module 250, the speaker system 224, the haptic actuator 222, and the like may be connected to the chassis 219 (e.g., along a rearward side of the chassis 219). By connecting components to the chassis 219 in place of the front cover assembly 201 and / or the rear cover 272, the cost and complexity of the front cover assembly 201 and the rear cover assembly 273 may be reduced and the removal and / or replacement of the front cover assembly 201 and / or the rear cover 272 may be simplified. Chassis 219 may also include one or more holes extending therethrough to facilitate connection of components on one side of chassis 219 (e.g., display 203 and / or sensors of front cover assembly 201) to components on the other side of chassis 219 (e.g., circuit board assembly 220). Moreover, as mentioned above, the chassis 219 may also be thermally coupled to components of the device 200, such as the circuit board assembly 220, to dissipate heat from the thermally coupled components.The chassis 219 may provide a thermal performance function for the device 200. For example, heat generating components (e.g., the circuit board assembly 220 and / or the components thereon) may be thermally coupled to the chassis 219 such that heat may be transferred from the circuit board assembly 220 to the chassis 219. Moreover, the chassis 219 and the thermal connection between the circuit board assembly 220 and the chassis 219 may be configured such that the heat is preferentially dissipated from the outer walls of the housing structure 210 (or otherwise the transfer of heat to the outer walls is inhibited). For example, thermal bridges (which may also be referred to as thermal pipes or thermal coupling components) may thermally couple the circuit board assembly 220 to the chassis 219, and may preferably be positioned towards the center of the device (e.g., along the x-direction) such that the heat tends to be conducted away from the sidewalls into the chassis 219. In some cases, the thermal bridges are positioned about 5 mm, about 10 mm, about 15 mm, or about 20 mm away from the proximal housing component (measured in the x-direction). The chassis 219 may also include thermal interruptions that inhibit heat transfer from the chassis 219 to the housing components. For example, one or more holes may be formed through the chassis 219 between the housing components and the thermal bridges (or other areas where heat is transferred to the chassis 219) to inhibit heat transfer to the housing components. These and other features of thermal management are described herein.In some cases, rather than having multiple separate, attached housing components (e.g., a housing subassembly), the housing segment 217 may be a unitary molding from a single piece of material. For example, the unitary structure of the housing segment 217 may be made of a metal such as aluminum, steel, titanium, or the like, and formed by extrusion, machining, and / or combinations thereof and other forming processes. Thus, the housing components 211 and 214 (which form the exterior surfaces of the device 200) and the chassis 219 may be made from different portions of a single piece of material. In some cases, the housing segment 217 may be formed from separate components that are secured together. For example, the housing components 211, 214 may be formed as separate components from the chassis 219, and then the housing components 211, 214 may be welded, soldered, bonded, or otherwise secured to the chassis 219 to form the housing segment 217. As described herein, the housing components 211, 214 may be bimetallic enclosure structures (e.g., an enclosure of titanium over an aluminum core) and the chassis 219 may be made of aluminum. The core portions of the aluminum shell structures may be welded to the aluminum chassis 219.As described above, the housing structure 210 may include housing components 212, 213, 215, and 216 structurally interconnected to each other and / or to the housing segment 217 (the middle housing segment 217) via hinge structures 218. The interconnect structures 218 (e.g., the material of the interconnect structures) may extend over inner surfaces of the package components. In particular, a portion of the interconnect structures 218 may contact, cover, encapsulate, and / or engage the features of the housing components extending from the interior surfaces of the housing components (e.g., also from the housing components of the middle housing component 214). Because the housing components 214 and 211 are connected to a housing segment 217 that encloses the chassis 219, the connection structures 218 may also serve to structurally connect the housing components 212, 213, 215 and 216 to the housing segment 217. The housing segment 217, the housing components 212, 213, 215 and 216, and the connection structures 218, when interconnected via the connection structures 218, may form a main housing assembly that defines the exterior side surfaces of the device 200 as well as the chassis 219 within the device.The housing components 211, 212, 213, 214, 215 and 216 may be formed from aluminum, stainless steel or other metal. In some cases, the housing components 211, 212, 213, 214, 215 and 216 may be formed from a metal enclosure structure. For example, the housing components may include a core portion formed from a first metal (e.g., aluminum) and a sheath portion formed from a second metal (e.g., titanium, stainless steel). The enclosure portion may define outer surfaces of the housing components. The housing components may be formed into a precursor material for the cladding by co-extrusion of the core portion and the cladding portion. The precursor material may then be formed into housing components (e.g., extruded profiles) in various processes. For example, the precursor material may be forged and / or machined to determine the general shape and mechanical characteristics of the package components, and then subjected to polishing, patterning, and / or coating operations.In some cases where holes are formed through the enclosure and core portion of an enclosed housing component (e.g., for buttons, audio components, charging ports, etc.), a seam may be present between the housing portion and the core portion within the hole (e.g., along the surface of the hole). In some cases, the seam may be covered with another material, such as a paint, an adhesive, a polymer layer, or the like. Covering the seam may help prevent galvanic corrosion at the seam by contact with water or other liquid.In some cases, a metal deposition process is used to create holes through a package component that do not include seams along the hole surface. For example, a hole may be formed through the housing by first forming a hole through only the core material. Subsequently, additional material for the cladding is introduced into the hole (e.g., by a process of direct metal deposition) such that the material for the cladding substantially fills the hole through the core portion. A final hole is then formed through the cladding material as well as the additional cladding material (added by the metal deposition process) such that the entire hole surface is formed by the casing component of cladding material (e.g., the core material does not define the hole surface). In this way, there is no seam between different metals in the hole, which weakens the risk of galvanic corrosion within the hole.Mechanical features may include locking structures for locking to connection structures (e.g., for mechanically coupling housing components), fastening features (e.g., holes for receiving fasteners), surfaces, antenna feed and ground points, and the like. In some cases, the exterior surface of the package components is subjected to patterning such as grinding, lapping, machining, ablation, blasting (e.g., sandblasting, pearlescent), etching (by mechanical etching, laser etching, chemical etching, or the like), or the like. Some or all surfaces of the package components may also be coated, such as by PVD or CVD methods. For case components that are curved (e.g., components 212, 213, 215, and 216 that form corner portions of case structure 210), the plated precursor material may be bent prior to other machining operations such as machining, forging, polishing, grinding, coating, and the like. After molding, the housing components (including the housing segment 217) may be inserted into a mold and joined together by injection molding a moldable material to form the joining structures 218 that engage the housing components and join the components together to define the housing structure 210.The housing segment 217 may be formed by welding the housing components 211, 214 to the chassis portion 219. The chassis portion 219 may be formed of metal, such as aluminum, and welded to an aluminum core portion of the housing components 211, 214. In some cases, the chassis portion 219 may be soldered or bonded to the housing components 211, 214 rather than welding or additionally welding. The central chassis portion 219 may be conductively and structurally connected to the housing components 211, 214.As described herein, the housing components 212, 213, 215, and 216, as well as the housing components 211, 214, may provide a robust and shock resistant sidewall for the device 200. In the present example, the housing components 212, 213, 215 and 216, as well as the housing components 211, 214, form a flat side wall that extends around the circumference of the device 200. The flat sidewall may include rounded or beveled edges that form the top and bottom edges of the sidewall of the housing structure 210. The housing components 212, 213, 215 and 216 and the housing components 211, 214 may each include a flange portion or lip that extends around and at least partially covers a corresponding portion of the front and rear covers 202, 272. No materials or spaces may be located between the flange or lip portion and the respective side surface of the front and rear covers 202, 272. As a result, forces or shocks applied to the housing structure 210 may be transmitted to the front and rear covers 202, 272 without compromising the display or other internal structural elements, which may improve dropping performance of the device 200.Device 200 may also include a button 285 (which may correspond to button 121 in FIG. 1A ) having a touch sensor on an exterior surface. For example, the button 285 may sense force inputs (or translation or pressure inputs), but also touch inputs on the surface of the button. Force inputs may be detected by a strain gauge system, switch, or other suitable force and / or gear ratio sensor (and / or combinations of sensors, such as a hinged dome switch in combination with a force sensor).Touch inputs may be sensed by a touch sensing system, such as a capacitive touch sensing system. For example, the tactile element of the button 285 (e.g., the movable component that a user presses to actuate the button or provide input) may include a touch sensitive element positioned thereon. A key equipped with a touch-sensitive element may sense various types of touch-based inputs, including static touch inputs (e.g., a finger touching the touch-sensitive surface of the key), dynamic touch inputs (e.g., a finger sliding over the touch-sensitive surface of the key, also referred to as gesture or stroke inputs), or the like. In some cases, the button 285 may include a touch-sensitive element to sense such touch-based inputs. As described herein, the button 285 may operate in conjunction with a haptic actuation system, such as the haptic actuator 222, to generate tactile outputs in response to detecting input at the button 285 (e.g., force inputs, touch inputs, etc.).As shown in FIG. 2, the device 200 includes one or more antennas that may be capable of performing wireless communication using a 5G communication protocol. For example, the device 200 may include an antenna module 247, which may include one or more antenna arrays, which may be configured to transmit and receive wireless communication signals via the back cover 272 and / or via another housing component of the device (e.g., a radio frequency transmitting component of the device or housing).The antenna modules may include multiple antenna arrays. For example, the antenna modules may include one or more arrays of millimeter wave antennas. If the antenna modules include multiple arrays of millimeter wave antennas (each of which may include one or more radiating elements), the multiple arrays of millimeter wave antennas may be configured to operate according to a diversity scheme (e.g., spatial diversity, pattern diversity, polarization diversity, or the like). The antenna modules may also include one or more ultra-wideband antennas.The antenna arrays may be suitable for 5G communication in the millimeter wave range and may be used to adapt signal reception depending on the application with beamforming or other techniques. The apparatus 200 may also include multiple antennas for performing multiple-in-multiple-out (MIMO) wireless communication schemes, including 4G, 4G LTE, and / or 5G MIMO communication protocols. As described herein, one or more of the package components 211, 212, 213, 214, 215, and 216 (or portions thereof) may be suitable to operate as antennas for a MIMO wireless communication scheme (or other wireless communication scheme).FIG. 3 shows an exploded view of an example electronic device. In particular, FIG. 3 shows an exploded view of a device 300 showing various components of the device 300 and example arrangements and configurations of the components. The apparatus 300 may be an embodiment of the apparatus 140, and the description of the various components and elements of the apparatus 100 of FIGS. 1A and 1B may also be applicable to the apparatus 300 illustrated in FIG. 3. Redundant description of some components will not be repeated here for clarity.As shown in FIG. 3, the device 300 includes a cover 302 (e.g., a front cover) that may be formed from or include a transparent or optically transmissive material. In some cases, the cover 302 is formed from or includes a glass material or other suitable transparent or optically transmissive material (e.g., silica-based glass material, aluminosilicate glass, borosilicate glass, alkali metal aluminosilicate glass, chemically tempered glass, sapphire, ceramic, glass ceramic, crystallizable glass materials, or plastic). In this example, the cover 302 may be formed of a 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 the strength or other properties of the cover 302. A glass ceramic material may be silica-based glass ceramic material, such as an aluminosilicate glass ceramic material or a borosilicate glass ceramic material. The glass ceramic material can be chemically hardened by ion exchange. In some cases, the cover 302 may include a sheet of chemically solidified material having one or more coatings, including an anti-reflective (AR) coating, an oleophobic coating, or another type of coating or optical treatment. In some cases, the cover 302 includes a sheet of material 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 about 0.60 mm or less, or about 0.50 mm or less. The cover 302 may be chemically solidified using an ion exchange process to form a compressive stress layer along the outer surfaces of the cover 302.The cover 302 extends substantially across the entire front surface of the device and may be positioned in an opening bounded by the housing structure 310. In some cases, the edges or sides of the cover 302 may be surrounded by a protective flange or lip of the housing structure 310 without an intervening component being present between the edges of the cover 302 and the respective flanges of the housing structure 310. This configuration may allow an impact or force applied to the housing structure 310 to be transmitted to the cover 302 without transmitting shear stresses directly via the display 303 or the frame 304.As shown in FIG. 3, the display 303 is attached to an inner surface of the cover 302. The display 303 may include an organic light emitting diode (OLED) display that measures 15.4 cm (6.1 inches) from corner to corner. The perimeter or non-active area of the display 303 may be reduced to allow very thin edges of the device around the active area of the display 303. In some cases, the display 303 allows edge regions of 1.5 mm or less. In some cases, the display 303 allows edge regions of 1 mm or less. In an example implementation, the edge region is about 0.9 mm. The display 303 may have a relatively high pixel density of about 460 pixels per inch (PPI) or more. In some cases, the display 303 has a pixel density of about 475 PPI. The display 203 may use a back plate of low temperature polycrystalline silicone (LTPS) or low temperature polycrystalline oxide (LTPO).The display 303 may include an on-cell (integrated touch sensing system). For example, an array of electrodes (or other touch sensitive components) integrated into the OLED display may be operated in time and / or frequency division multiplexing to provide both a display and touch sensitivity function. The electrodes may be configured to sense the location of a touch, gesture input, multi-touch input, or other types of touch inputs along the outer 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-sensitive and / or force-sensing components or layers positioned between the display 303 and the cover 302.The display 303, also referred to as a display stack, may include the function "Ways-on-Display" (AOD). For example, the display display 303 may be configured to display designated regions or subsets of pixels 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 mode or idle. This may display the time, date, battery status, latest notifications, and other graphical content in a lower power mode or idle state. This graphical content may be referred to as persistent or constantly active graphical output. Although a certain battery current can be consumed in the display of continuously switched-on graphics, the energy consumption is usually lower than in the case of normal or full-load operation of the display 303. This function may be activated by operating only a subset of the display pixels and / or at a reduced resolution to reduce the power consumption of the display 303.The display 303 may include multiple layers, including touch sensitive layers or components, optional force sensing layers or components, display layers, and the like. The display 303 may define a graphically active region in which graphical outputs may be displayed. In some cases, portions of the display 303 may include graphically inactive regions, such as portions of the display layers that do not include active display components (e.g., pixels) or are otherwise not configured to display graphical outputs. In some cases, graphically inactive regions may be located along the peripheral edges or other edges of the display 303.As shown in FIG. 3, the device 300 may also include a frame member 304, also referred to simply as frame 304, positioned below the cover 302 and extending around the outer perimeter of the display 303. The frame 304 may be attached to a bottom or inner surface of the cover 302. A portion of the frame 304 may extend below the display 303 and attach the cover 302 to the housing structure 310. Because the display 303 is attached to a bottom or inner surface of the cover 302, the frame 304 may also be referred to as attaching both the display 303 and the cover 302 to the housing structure 310. The frame 304 may be formed from a polymeric material, a metallic material, or a combination of polymeric and metallic materials. The frame 304 may support elements of the display stack, provide anchor points for flexible circuits, and / or may be used to attach other components and devices. In some cases, the frame 304 includes one or more metallic or conductive elements that provide shielding between the components of the device, such as between the display stack (including display components and touch sensor components) and other components such as the haptic actuator 322, the speaker system 324, and the like.The cover 302, display or display stack 303, and frame 304 may be part of a front cover assembly 301 of the device 300. The front cover assembly 301 (e.g., a front cover of the front cover assembly) may form a front exterior surface of the device. The cover 302 may have an inner surface opposite the outer surface. The front cover assembly 301 may be assembled as a sub-assembly, which may then be attached to a housing component. 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 perimeter of the display stack 303. The front cover assembly 301 may then be secured to a housing component of the device 300 by securing and adhering the frame member 304 to a ledge defined by the housing component.The apparatus 300 also includes a speaker module 350 configured for sound output via a speaker port. The speaker port may be positioned in and / or at least partially bounded by a depression or notch formed along one side of the cover 302. As described herein, a portion of the shroud may be at least partially positioned in the recess or notch to facilitate the discharge of sound while inhibiting the ingress of dirt, liquid, or other materials or contaminants into the device 300. Output from the speaker module 350 may be through an acoustic passageway or path defined at least in part by the speaker module 350 itself and the piece. In some cases, a portion of the acoustic path (e.g., between the speaker module 350 and the patch) is defined by the housing structure 310 and / or a molded material connected to the housing structure 310. For example, a molded material (e.g., a fiber reinforced polymer) may be molded against a metallic portion of the housing portion 310 (e.g., the housing component 313 described herein). The molded material may also form one or more intermediate members, such as interconnect structures, that also structurally connect package components together (e.g., interconnect structures 318). A port or passage (e.g., a tubular tunnel) may be defined by the molded material to acoustically couple the speaker module 350 to the piece and / or the depression generally, thereby conducting the sound from the speaker module 350 to the exterior of the device 300.As shown in FIG. 3, the device 300 also includes one or more cameras, optical emitters, and / or sensor elements configured to transmit, receive, or otherwise operate signals along the front surface of the device. In this example, the device 300 includes a front camera 306 having a high resolution camera sensor. The front camera 306 may include a sensor with a resolution of 12 megapixels and optical elements that provide a field of view of 85°. The front camera 306 may have a shutter of f / 1.9. The front camera 306 may include an autofocus function in which one or more of the lens elements move (e.g., up to about 100 micrometers perpendicular to the cover) to focus an image on the camera sensor. In some cases, the forward autofocus camera may provide a continuous autofocus function during video capture. The apparatus 300 also includes a face detection optical system 352 that includes an infrared light projector (for projecting light) and an infrared light sensor configured to sense an array of depth points or regions along the user's face. The array of depth points may be characterized as a unique signature or bioidentification that may be used to identify and / or authenticate the user and unlock the device 300 (and / or authorize functions on the device 300 such as purchase software apps or use payment functions provided by the device 300).The device 300 may also include one or more other sensors or components. For example, the apparatus 300 may include an illumination element for the front camera 306 that provides flash light or illumination to the front camera 206. The apparatus 300 may also include an ambient light sensor (ALS) that serves to sense the ambient light conditions to adjust the exposure aspects of the front camera 306 and / or control the operation of the display. The device 300 may also include a proximity sensing system 353 to sense the proximity of a user or other object to the device 300. In some cases, as described herein, the proximity sensing system 353 senses proximity to other objects via an active region of the display. The proximity sensing system 353 and the optical face sensing system 352 may be integrated into a common module. In some cases, the information of both the proximity sensing system and the ambient light sensor is used to determine the ambient light conditions and / or the proximity of objects to the device 300. For example, information from the proximity sensing system may be used to determine whether a low ambient illumination sensed by the ambient light sensor is due to a low ambient illumination or an object that locally or temporarily covers the ambient light sensor (e.g., a finger making a touch input or a palm on an input). The information of both sensing systems may be used to distinguish between potentially ambiguous states and generally improve the accuracy with which the device may sense certain states.FIG. 3 also illustrates one or more cameras, optical transmitters, and / or sensor elements configured to transmit signals, receive signals, or otherwise operate along the rear surface of the device. As shown in FIG. 3, these elements may be part of a sensor array 360. In this example, the sensor array 360 includes a first camera 361 having a 48.8 megapixel image sensor (optionally having a three layer sensor array) and a wide angle lens with an aperture of f / 1.6. The sensor array 360 may also include a second camera 362 having a 12 megapixel image sensor and a super wide angle lens (120° FOV) with an f / 2.4 f-number. The sensor array 360 also includes a light source that can be used as a flash for photography or as an auxiliary light source (e.g., flash light). In some cases, the sensor array 360 also includes a microphone, an ambient light sensor, a depth sensing device, and / or other sensors suitable for measuring along the rear surface of the device 300. The first and second cameras 361, 362 (and / or the camera lenses of the first and second cameras 361, 362) may be arranged (e.g., centered) on a line extending along the y-direction of the device.As shown in FIG. 3, cameras 361 and 362 may be aligned with camera covers 363 and 364, respectively. The covers 363, 364 may be formed of a glass, glass ceramic, or sapphire material and provide a clear (e.g., transparent or optically transmissive) window through which the cameras 361, 362 may capture a photographic image. In other cases, the covers 363, 364 are optical lenses that filter, magnify, or otherwise put light received from the respective camera 361, 362. The other sensing or transmitting elements of the sensor array 360 may transmit and / or receive signals via a region of the back cover 372 or via a separate cover connected to the back cover 372. As shown in FIG. 3, the covers 363, 364 may extend beyond the outer surface of the cover 372 and form a recess along the inner surface of the cover 372 such that the lenses or other elements of the cameras 361 and 362 may protrude into the respective recesses. In this manner, the device 300 may capture a larger lens or other elements of the cameras 361 and 362 than would be possible if the recess were not provided. In some cases, the trim assemblies 365, 366 may be connected to the rear cover 372 and support the covers 363, 364.A battery 330 is also included in the device 300. 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 enclosed by a foil or other enclosure member (e.g., a rigid shell of metal as described in the battery 230). The battery 330 may include a rolled electrode configuration, sometimes referred to as a "jelly roll" or a folded or stacked electrode configuration.The battery 330 may be secured to the device 300 (e.g., to a chassis portion 323) using one or more adhesives and / or other attachment techniques. In one example, the battery 330 may be secured to the chassis portion 323 or other structure of the device 300 with an electrically releasable adhesive (e.g., an adhesive whose adhesive strength may be selectively decreased in response to an electrical charge). In such cases, the adhesive may include conductive terminals that are in conductive contact with the electrically releasable adhesive. When the electrically releasable adhesive (EDA) is supplied with electrical power (e.g., by a user during a battery change), the adhesive force of the adhesive may be reduced until the battery disengages from the adhesive and / or the chassis portion 323 or until the adhesive force is so low that the battery may be easily removed by a user (e.g., without damaging the battery or other components of the device).The battery 330 may be charged via a port 332 (e.g., via a charging cord inserted into the port 332 through a charging port 326) and / or via a wireless charging system 340. The charging port 332 may be or include a connector port. The battery 330 may be connected to the charging port 332 and / or the wireless charging system 340 via control circuitry that controls the energy provided to the battery and the energy provided from 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 connects to an output or transmit coil of a wireless charging device. 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 comprising multiple turns of a conductive wire or other lead configured to generate a (charging) current in response to placement in an induction electromagnetic charging field generated by a separate wireless charging device or accessory. The coil assembly 342 also includes an array of magnetic elements arranged in a circular or radial pattern. The magnetic elements may help locate the device 300 with respect to a separate wireless charging accessory or other device. In some implementations, the array of magnets also helps radially locate, align, or "clock" the device 300 with respect to the separate wireless charging device or other accessory. For example, the array of magnets may include a plurality of magnetic elements of alternating magnetic polarity arranged in a radial pattern. The magnetic elements may be arranged to provide magnetic coupling with the separate charger in a particular orientation or a series of discrete orientations to aid in positioning the device 300 with respect to the separate charger or other accessory. This functionality may be referred to as self-aligning or self-locating wireless charging. As shown in FIG. 3, the device 300 also includes a magnetic reference point 344 to locate the location of the separate wireless charging device or accessory.In one example, the magnetic reference point 344 is adapted to magnetically connect to a separate wireless charging device or other accessory. By coupling to the separate wireless charging device / accessory, the rotational orientation of the device 300 and the separate wireless charging device / accessory may be maintained with respect to an absolute or single position. The magnetic coupling of the charging device / accessory to the rear surface of the device 300 also allows the charging device or other accessory to be more securely connected 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 an NFC antenna capable of receiving and / or transmitting wireless communications between the device 300 and the wireless charger or other accessory. In some cases, the device 300 is capable of performing wireless communication to detect or detect the presence of the wireless charger or other accessories without using a dedicated NFC antenna. The communication may also include information about the state of the device, the state of charge of the battery 330, and / or control signals for increasing the charging process, for decreasing the charging process, for starting the charging process, and / or for ending the charging process for a wireless charging process.The wireless charging system 340 may also include one or more graphite layers (or other thermally conductive layers) that improve the thermal performance of the wireless charging system 340 and / or the device itself. For example, the graphite layers on the wireless charging system 340 may dissipate and / or distribute the heat of the coil during the charging process. In some cases, the graphite layers may absorb and transfer heat from other components, such as from the battery 330.The device 300 may also include a speaker system 324. The speaker system 324 may be positioned in the device 300 such that a corresponding port 325 is aligned with or proximate to an audio output of the speaker system 324. Accordingly, the sound output by the loudspeaker system 324 exits the housing structure 310 via the respective connection 325. The speaker system 324 may include a speaker positioned in a housing defining a speaker volume (e.g., an empty space in front of or behind a speaker diaphragm). The volume of the speaker may be used to tune the audio output of the speaker and optionally mitigate destructive interference of the sound produced by the speaker.The device 300 may also include a haptic actuator 322. The haptic actuator 322 may include a movable mass and an actuation system 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 cooperate to establish movement. The magnets may be made of or include reused magnetic material.When the coil(s) is / are energized, the coil(s) may / are capable of moving the mass, causing a force to be applied to the device 300. The movement of the mass may be configured to cause vibration, momentum, knock, or other tactile output that may be detected via an outer surface of the device 300. The haptic actuator 322 may be configured to move the mass linearly, but other movements (e.g., rotational) are also conceivable. Instead of or in addition to the haptic actuator 322, other haptic actuators may also be used.The haptic actuator 322 may be configured to move the mass along the y-direction to produce a haptic output. In some cases, the movement of the mass in the y-direction is tuned to produce a tactile output that is substantially similar to a haptic actuator configured for movement in the x-direction. When the haptic actuator 322 is configured to move the mass along the y-direction (e.g., instead of the x-direction), the haptic actuator 322 may be aligned primarily along the y-direction (e.g., the long axis of the haptic actuator 322 extends along the y-direction), which may allow for greater packaging efficiency of the components within the device 300.In some cases, the haptic actuator 322 is configured to generate a first haptic output in response to the device detecting that a force input applied to a button (e.g., a button having a strain or other force sensing element) satisfies a force threshold, and is also configured to generate a second haptic output in response to a notification event (e.g., an event associated with a haptic notification or upon occurrence of which the device generates a haptic output). Thus, the same haptic actuator 322 may be used to generate haptics for notifications, simulate keystrokes, or otherwise indicate that an input satisfying a force threshold has been received.The apparatus 300 also includes a circuit board assembly 320. The circuit board assembly 320 may include a substrate as well as processors, memory, and other circuit elements connected to the substrate. The circuit board assembly 320 may include multiple circuit boards stacked and interconnected to maximize the range available for electronic components and circuitry in a compact form factor. The circuit board assembly 320 may include provisions for a subscriber identity module (SIM). The circuit board assembly 320 may include electrical contact assemblies and / or a SIM slot assembly that receives a physical SIM card, and / or the circuit board assembly 320 may include provisions for an electronic SIM card. When using an electronic SIM card, the device 300 may manage without a SIM drawer (e.g., the device may not include any openings, slots, slots, doors, or other mechanical means for inserting or otherwise accessing a SIM card). The circuit board assembly 320 may be fully or partially encapsulated to reduce the risk of damage from water or other fluids ingress.The circuit board assembly 320 may be thermally connected to a chassis portion 323 of the housing structure 310. As described herein, the chassis portion 323, also referred to simply as chassis 323, may be part of a housing segment 314 (e.g., a middle housing component) formed from a unitary structure and defining the chassis 323, as well as a first wall portion 317 defining a first outer surface of the device 300 and a second wall portion 319 defining a second outer surface of the device 300. The circuit board assembly 320 may be thermally coupled to the chassis 323 via one or more thermal bridges, such as a graphite structure, a graphite wrapped foam, or other thermally conductive structures. The heat of the circuit board assembly may be transferred to the chassis 323 via the thermal bridges, thereby dissipating heat from the circuit board assembly 320 (where heat may affect durability, performance, or the like) and also dissipating heat from exterior surfaces and / or components of the device 300 that contact a user (e.g., the wall portions 317, 319 that define exterior side surfaces of the device and that may be held by a user when the device 300 is in use).The circuit board assembly 320 may also include wireless communication circuitry operatively coupled to and / or otherwise using wall portions and / or housing components 312, 313, 317, 315, 316, or 319 (or portions thereof) as radiating elements or structures to provide wireless communication. The circuit board assembly 320 may also include components such as accelerometers, gyroscopes, circuitry for near field communication and / or antennas, compass, and the like. In some implementations, the circuit board assembly 320 may include a magnetometer suitable for sensing and / or locating an accessory. For example, the magnetometer may be capable of detecting a magnetic (or non-magnetic) signal generated by an accessory of the device 300 or another device. The output of the magnetometer may include a directional output that may be used to display a directional indication or other navigation guidance on the display 303 to guide the user to a location of the accessory or other device.The apparatus 300 may also include one or more pressure transducers capable of sensing changes in external pressure to determine changes in elevation. The pressure sensors may be provided with external terminals and / or positioned in a watertight inner volume of the casing treatment 310. The output of the pressure sensors may be used to track the steps being traversed, the location (e.g., a floor) of a multi-level structure, the movements performed during activity to estimate physical effort or calorie consumption, or other relative movements of the device 300.The circuit board assembly 320 may also include global positioning 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)) to estimate an absolute location of the device 300. In some implementations, the GPS electronics may use two frequency bands. For example, GPS electronics may use L 1(L 1C), L 2(L 2C), L 5, L1+L 5, and other GPS signal bands to estimate the location of device 300.As shown in FIG. 3, the housing may include a cover 372 (e.g., a back cover) that defines substantially the entire back surface of the device 300. The back cover 372, the front cover 302, and the housing structure 310 may at least partially form a shell of the device 300 that may define an interior volume in which components of the device 300 are positioned. The cover 372 may be formed of or include a transparent or optically transmissive material. For example, the cover 372 may include a substrate made of or based on a glass material or other suitable material (e.g., silica-based glass material, aluminosilicate glass, borosilicate glass, alkali metal aluminosilicate glass, chemically tempered glass, sapphire, ceramic, glass ceramic, crystallizable glass materials, or plastic). A glass ceramic material may be silica-based glass ceramic material, such as an aluminosilicate glass ceramic material or a borosilicate glass ceramic material. The glass ceramic material can be chemically hardened by ion exchange. The substrate may have portions less than 1 mm thick. In some cases, the substrate has portions less than 0.80 mm. In some cases, the substrate has portions that are about 0.60 mm or less. The cover 372 may have a uniform thickness or, in some cases, a thickened or raised portion surrounding the camera covers 363, 364. The back cover 372 may be machined (e.g., ground) to a final shape before being polished and / or textured to provide the desired surface. The texture may be configured to provide a matt appearance while being resistant to the accumulation of skin, lint or other debris.The cover 372 may be formed of a colored optically transmissive material and may include a coating along an inner side of the cover 372 that, along with the color (or lack of color) of the optically transmissive material, determines the color of the back of the device. For example, a coating along an inner surface of the cover may include one or more color layers. The colored layer may include a coloring agent such as a pigment or a dye and have a certain hue or a nearly neutral color. Alternatively or additionally, the coating may include one or more opaque layers that are applied to (or otherwise positioned along) the inner surface of the substrate to provide a particular appearance to the back of the device. The opaque layer(s) may include a sheet, ink, dye, or combinations of these (or other) layers, materials, or the like, and in some cases may be optically dense.The cover 372 may be part of a rear cover assembly 373. The rear cover assembly 373 may be connected to the housing structure 310. In some cases, the rear cover assembly 373 includes components such as the camera covers 363 and 364, trim assemblies 365, 366, components of a wireless charging system, structural components (e.g., frames), other trim assemblies, fastening clips, and / or other components, systems, subsystems, and / or materials.The rear cover assembly 373 may include a bracket 371 connected to an inner surface of the rear cover 372. The support plate 371 may be bonded to the inner surface of the back cover by an adhesive.The support plate 371 may be made of metal (e.g., aluminum) and form a patterned attachment surface for components of the back cover 373 (e.g., a wireless charging system). In some cases, the trims 365, 366 are secured to the support plate, such as by welding, brazing, brazing, or other suitable fasteners. The support plate 371 may be a unitary metal structure that extends substantially across the entire inner surface of the back cover 372 (e.g., including a region for wireless chargers and a region for the rear-facing camera). In other examples, the support plate 371 may be comprised of multiple separate components of metal. If the support plate 371 is formed from multiple separate components of metal, the components may be made of the same metal (e.g., both aluminum or both stainless steel), or they may be made of different materials as described above with respect to the metal components 282 (the discussion about which refers to a multi-component support plate 371).The support plate 371 may be thermally coupled to other components of the device, such as via thermal bridges, as described herein. Examples of thermal bridges include graphite wrapped foam (e.g., a graphite layer wrapped around a foam or other compliant material), conductive loops (e.g., a graphite or other thermally conductive layer on a loop structure formed by a substrate), direct metal-to-metal contacts, thermal paste or heat gel, or the like. Thermal bridges may thermally connect the support plate 371 to components such as the circuit board assembly 320, the battery 330, and the sensor array 360. The support plate 271 may be formed of a heat conductive material such as a metal (e.g., aluminum), and the heat of the other components may be transferred to the support plate 371. The support plate 371 may therefore function as a heat sink and generally spread the heat throughout the support plate 371, which may contribute to reducing the peak temperatures of the device or components.Similar to that described above with respect to the cover 302, the cover 372 may be at least partially positioned within an opening defined in the housing structure 310. Similar to the cover 302, the edges or sides of the cover 372 may be surrounded by a protective flange or lip of the housing structure 310 without an intervening component between the edges of the cover 372 and the respective flanges of the housing structure 310. The cover 372 may be chemically solidified by an ion exchange process to form a compressive stress layer along the outer surfaces of the cover 372. In some cases, the (rear) cover 372 is formed of the same or similar material as the (front) cover 302.The back cover 372 may be removably coupled to the remainder of the casing treatment 310, such that the back cover 372 may be quickly and efficiently removed and / or replaced. In some cases, the wireless charging system 340 is the only component that is mounted to the rear cover 372 and must be electrically coupled to the circuit board assembly 320 (which is connected to the housing segment 314). Accordingly, the rear cover 372 may be fully removed from the device by detaching the rear cover 372 from the rest of the housing (e.g., from the housing segment 314) and decoupling the electrical connectors of the wireless charging system. In this way, the device 300 may provide improved repairability.The housing structure 310 may include a housing segment 314 (e.g., a middle housing segment 314) comprising the wall portions 317 and 319 and the chassis portion 323 (e.g., a metal plate-like structure extending between the wall portions 317 and 319). The chassis 323 may form a mounting structure for components of the apparatus 300. For example, as described herein, components such as the circuit board assembly 320, the battery 330, the sensor array 360, the speaker module 350, the speaker system 324, the haptic actuator 322, and the like may be connected to the chassis 323 (e.g., along a rearward side of the chassis 323). By connecting components to the chassis 323 instead of the front cover assembly 301 and / or the rear cover 372, the cost and complexity of the front cover assembly 301 and the rear cover assembly 373 can be reduced, and the removal and / or replacement of the front cover assembly 301 and / or the rear cover 372 can be simplified. The chassis 323 may also include one or more holes extending therethrough to facilitate connection of components on one side of the chassis 323 (e.g., the display 303 and / or the sensors of the front cover assembly 301) to components on the other side of the chassis 323 (e.g., the circuit board assembly 320). Moreover, as mentioned above, the chassis 323 may also be thermally coupled to components of the device 300, such as the circuit board assembly 320, to dissipate heat from the thermally coupled components.The housing segment 314 may be a unitary structure formed from a single piece of material. For example, the unitary structure of the housing segment 314 may be made of a metal such as aluminum, steel, titanium, or the like and formed by extrusion, machining, and / or combinations thereof and other forming processes. Thus, wall portions 317 and 319 (which form the outer side surfaces of device 300) and chassis 323 may be different portions of a single piece of material. In some cases, the housing segment 314 is formed from a polymeric material, reinforced polymeric material (e.g., fiber reinforced), carbon fiber, or another suitable material. In some cases, the wall portions 317, 319 may be separate housing components connected to the chassis 323, similar to the construction of the housing segment 217 described above.As described above, the housing structure 310 may include housing components 312, 313, 315, and 316 structurally interconnected to one another and / or to the housing segment 314 (the middle housing segment 314) via hinge structures 318. The interconnect structures 318 (e.g., the material of the interconnect structures) may extend over inner surfaces of the package components. In particular, a portion of the interconnect structures 318 may contact, cover, encapsulate, and / or engage features of the housing components extending from the interior surfaces of the housing components (e.g., from the wall portions of the middle housing segment 314). Because wall portions 317 and 319 are part of a single unitary structure, connecting structures 318 may also serve to structurally connect housing components 312, 313, 315 and 316 to housing segment 314. The housing segment 314, housing components 312, 313, 315, and 316, and connection structures 318, when interconnected via the connection structures 318, may form a main housing assembly that defines the exterior side surfaces of the device 300 as well as the chassis 323 within the device.The housing components 312, 313, 315, and 316 may be formed of aluminum, stainless steel, or other metal. The housing components may also be formed from a packaging structure that includes multiple materials (as described above).In some cases where holes are formed through the enclosure and core portion of an enclosed housing component (e.g., for buttons, audio components, charging ports, etc.), a seam may be present between the housing portion and the core portion within the hole (e.g., along the surface of the hole). In some cases, the seam may be covered with another material, such as a paint, an adhesive, a polymer layer, or the like. Covering the seam may help prevent galvanic corrosion at the seam by contact with water or other liquid.In some cases, a metal deposition process is used to create holes through a package component that do not include seams along the hole surface. For example, a hole may be formed through the housing by first forming a hole through only the core material. Subsequently, additional material for the cladding is introduced into the hole (e.g., by a process of direct metal deposition) such that the material for the cladding substantially fills the hole through the core portion. A final hole is then formed through the cladding material as well as the additional cladding material (added by the metal deposition process) such that the entire hole surface is formed by the casing component of cladding material (e.g., the core material does not define the hole surface). In this way, there is no seam between different metals in the hole, which weakens the risk of galvanic corrosion within the hole.As described herein, the housing components 312, 313, 315, and 316, as well as the wall portions 317, 319, may provide a robust and shock resistant sidewall for the device 300. In the present example, the housing components 312, 313, 315 and 316, as well as the wall portions 317, 319 form a flat sidewall that extends around the perimeter of the device 300. The flat sidewall may include rounded or beveled edges that form the top and bottom edges of the sidewall of the housing structure 310. The housing components 312, 313, 315 and 316 and the wall portions 317, 319 may each include a flange portion or lip that extends around and at least partially covers a corresponding portion of the front and rear covers 302, 372. No materials or spaces may be located between the flange or lip portion and the respective side surface of the front and rear covers 302, 372. As a result, forces or shocks applied to the housing structure 310 may be transmitted to the front and rear covers 302, 372 without compromising the display or other internal structural elements, which may improve dropping performance of the device 300.The device 300 may also include a button 385 (which may correspond to button 155 in FIG. 1C ) having a touch sensor on an exterior surface. For example, the button 385 may sense force inputs (or translation or pressure inputs), but also touch inputs on the surface of the button. Force inputs may be detected by a strain gauge system, switch, or other suitable force and / or gear ratio sensor (and / or combinations of sensors, such as a hinged dome switch in combination with a force sensor). Touch inputs may be sensed by a touch sensing system, such as a capacitive touch sensing system. For example, the tactile element of the button 385 (e.g., the movable component that a user presses to actuate the button or provide input) may include a touch sensitive element positioned thereon. A key equipped with a touch-sensitive element may sense various types of touch-based inputs, including static touch inputs (e.g., a finger touching the touch-sensitive surface of the key), dynamic touch inputs (e.g., a finger sliding over the touch-sensitive surface of the key, also referred to as gesture or stroke inputs), or the like. In some cases, the button 385 may include a touch-sensitive element to sense such touch-based inputs. As described herein, the button 385 may operate in conjunction with a haptic actuation system, such as the haptic actuator 322, to generate tactile outputs in response to detecting input at the button 385 (e.g., force inputs, touch inputs, etc.).As shown in FIG. 3, the device 300 includes multiple antennas that may be capable of performing wireless communication using a 5G communication protocol. For example, the device 300 may include an antenna module 347, which may include one or more antenna arrays, which may be configured to transmit and receive wireless communication signals via the back cover 372 and / or via another housing component of the device (e.g., a radio frequency transmitting component of the device or housing). The antenna module may be attached to a back or bottom surface of the circuit board assembly 320.The antenna modules may include multiple antenna arrays. For example, the antenna modules may include one or more arrays of millimeter wave antennas. If the antenna modules include multiple arrays of millimeter wave antennas (each of which may include one or more radiating elements), the multiple arrays of millimeter wave antennas may be configured to operate according to a diversity scheme (e.g., spatial diversity, pattern diversity, polarization diversity, or the like). The antenna modules may also include one or more ultra-wideband antennas.Each of the antenna arrays (e.g., the antenna array and the millimeter wave arrays of the antenna module) may be suitable for 5G millimeter wave communication and operate or be used with beamforming or other techniques to adjust signal reception depending on the application. The apparatus 300 may also include multiple antennas for performing multiple-in-multiple-out (MIMO) wireless communication schemes, including 4G, 4G LTE, and / or 5G MIMO communication protocols. As described herein, one or more of the housing components 312, 313, 315, and 316 and the wall portions 317, 319 (or portions thereof) may be suitable to operate as antennas for a MIMO wireless communication scheme (or other wireless communication scheme).As described herein, a housing of a device may include thermal interruptions that inhibit heat transfer along certain paths in the device. FIG. 4A illustrates the housing structure 210 including a thermal discontinuity 404 defined by the chassis portion 219 of the housing segment 217. The thermal break 404 may be a through bore that extends through the chassis portion 219. The thermal break 404 may be positioned between the housing component 214 (forming a wall portion defining at least a portion of a side surface of the device 200) and a location where a processing element 400 on the circuit board assembly 220 is thermally coupled to the chassis portion 219 (e.g., a thermal coupling region 407, FIG. 4C ). For example, the circuit board assembly 220 may be connected to the chassis portion 219 and thermally coupled to the chassis portion 219 via a thermal bridge 402 in a thermal coupling region 407. The thermal bridge 402 may be positioned over or overlap the location of the processing element 400 on the circuit board assembly 220. In some cases, the circuit board assembly 220 includes a circuit board, and the processing element is connected to a first surface of the circuit board, and the thermal bridge is thermally connected to a second surface of the circuit board and positioned below the processing element. In some cases, the processing element 400 may be positioned between two circuit boards of the circuit board assembly 220. The thermal bridge 402 may be any suitable thermal bond, including a graphite wrapped foam, a thermally conductive loop structure, a thermally conductive paste or gel, a direct metal-to-metal bond, or other suitable thermal bridge. In some cases, a separate thermal bridge is not included, but the heat of the processing element 400 may thermally connect to the chassis portion 219 at the location identified as processing element 400 in FIG. 4A. As shown in FIG. 4A, the circuit board assembly 220, the processor 400, and the thermal bridge 402 may be positioned on a different side of the chassis portion 219 than shown in the figure.As described, the thermal break 404 may be positioned in a thermal path 409 that extends from the thermal coupling region (e.g., the location where the heat from the processor 400 or circuit board assembly is generally transferred to the chassis portion 219) to the wall portion defined by the housing component 214. As shown, the thermal path extends generally in the x-direction. The thermal break 404 thus interrupts the direct thermally conductive path through the chassis portion 219 (e.g., indicated by dashed arrows in FIG. 4A ) to the package component 214 (and thus to the exterior surface of the device) that would otherwise pass through the chassis portion 219, and is therefore configured to interrupt a flow of heat from the circuit board assembly to the package component 214 (e.g., the wall portion defined by the package component 214). Accordingly, the temperature of the outer surface along the housing component 214 may be lower than it would be if the chassis portion 219 were continuous along this path. As a result, the processor can also be operated at higher temperatures (which result from operation at higher processing power and / or processing speed) without an undesired increase in the temperature at the outer surface occurring. In this manner, the thermal break 404 may improve both thermal and operational performance (e.g., for processing) of the device.The through-hole of the thermal discontinuity 404 may form an elongated opening extending along a longitudinal axis, the longitudinal axis being parallel to the first exterior surface of the device (e.g., parallel to a y-direction of the device). The elongated opening extending along the y-direction of the device may provide thermal resistance along the x-direction while reducing material loss in the chassis portion 219 and maintaining structural integrity of the chassis portion 219. In some cases, the elongated opening may have a y-direction length equal to or substantially equal to the y-direction length of the thermal coupling region.While FIG. 4A illustrates heat being transferred from a processing element to the chassis portion 219, thermal interrupts may instead or additionally be positioned at other locations of the chassis portion 219 to interrupt heat transfer from other components as well. For example, the battery 230 may be thermally coupled to the chassis portion 219 at a particular location and a thermal break may be positioned between that location and a housing component. Thermal interruptions may be provided in the chassis portion 219 to also inhibit the transfer of heat from other components or heat sources.Thermal discontinuities may be positioned between a thermal coupling region on the chassis portion 219 and a proximal outer surface of the housing. Thus, a thermal break may provide a gap along a thermally conductive path that most likely causes a temperature increase at an exterior surface of the device.FIG. 4B shows a partial exploded view of the apparatus 200 showing the front cover assembly 201 separated from the housing structure 210. A heat diffusion element 410 may be positioned on the chassis portion 219 of the casing pattern 210. The heat diffusion element 410 may be formed from one or more layers of graphite or other thermally conductive materials and may adhere to one or more other materials. The thermal diffusion element 410 may have a thickness between about 10 microns and about 20 microns. The heat diffusion element 410 may extend over at least 80% of the first side of the chassis portion (or over 85%, or over 90% or over 95% of the first side of the chassis portion).The heat diffusion element 410 may be configured to generally receive heat from other components and spread the heat over a wide area. The heat diffusion member 410 may also release heat to the chassis portion 219. For example, the heat diffusion element 410 is positioned opposite a display of the front cover ( 201) (e.g., the lowermost layer of the display stack faces the heat diffusion element 410). The heat from the display may be transferred to the heat diffusion element 410 via an air gap (or by direct contact). The received heat may generally be dissipated through the heat diffusion element 410 and optionally into the chassis portion 219. Examples of the effects of the heat diffusion element 410 include reducing peak temperatures in the display and / or front cover assembly 201, dissipating heat from the display, and creating more uniform or uniform temperature profiles in the display and / or front cover assembly 201, and chassis portion 219.FIG. 4C is a partial cross-sectional view of the apparatus 200 as viewed along line 4C- 4C in FIG. 4B. FIG. 4C illustrates example positionings of various components within the device 200. As shown in FIG. 4C, the chassis portion 219 is positioned between the front cover assembly 201 and the rear cover assembly 273. The chassis portion 219 may form at least a portion of a first interior cavity 416 between the chassis portion 219 and the front cover 201 and at least a portion of a second interior cavity 417 between the chassis portion 219 and the rear cover assembly 273. The battery 230 and the circuit board assembly 220 may be positioned in the second interior cavity 417 between the chassis portion 219 and the back cover assembly 273. The battery 230 and the circuit board assembly 220 (and processing element 400) are additionally thermally coupled to the surface of the chassis portion 219 along the first side of the chassis portion 219, as described herein.For example, FIG. 4C illustrates the heat diffusion element 410 (e.g., one or more layers of graphite) positioned on a second side of the chassis portion 219 (in the first interior cavity 416) and below the front cover assembly 201 (e.g., across an air gap from the display 203, FIG. 2 ). FIG. 4C also shows the processing element 400 of the circuit board assembly 220 thermally coupled to a first side of the chassis portion 219 (opposite the second side) via the thermal bridge 402, and the thermal discontinuity 404 disposed between the location of the coupling and the outer surface defined by the housing component 214. As described, the circuit board assembly 220 is thermally coupled (e.g., via the thermal bridge 402) to the chassis portion 219 in the thermal coupling region 407.FIG. 4C also illustrates an example arrangement of the battery 230 within the device 200. For example, the battery 230 may be connected to the first side of the chassis portion 219, such as by adhesive 412. As described herein, the adhesive 412 may be an electrically degradable adhesive or another suitable adhesive. In some cases, a heat diffusion element 414 is positioned between the battery 230 and the first side of the chassis portion 219 (e.g., in areas where the adhesive 412 is not present). The heat diffusion member 414 may be connected to the chassis portion 219 and may or may not be in contact with the battery 230. The heat diffusion element 414 may be formed from one or more layers of graphite or other thermally conductive materials. The thermal diffusion element 414 can have a thickness between about 10 microns and about 20 microns. The heat diffusion member 414 can be configured to generally receive heat from other components and to spread the heat throughout the diffusion member 414 and also transfer heat to the chassis portion 219. For example, the heat from the battery 230 may be transferred to the heat diffusion element 414 via an air gap (or by direct contact), and the received heat may be generally distributed through the heat diffusion element 414 and optionally into the chassis portion 219. Examples of the action of the heat diffusion element 414 include reducing peak temperatures in the battery 230, dissipating heat from the battery 230, and creating more uniform or uniform temperature profiles in the battery 230 as well as in the chassis portion 219. In some cases, the heat diffusion element 414 is positioned between the battery 230 and the chassis portion 219 and also extends along other portions of the chassis portion 219 to be positioned between other components and the chassis portion 219. For example, a portion of the heat diffusion element 414 may be positioned between the circuit board assembly 220 and the chassis portion 219.While FIGS. 4A-4C use components of device 200 to illustrate various features and concepts, it should be understood that the same features and concepts apply to the corresponding components of device 300 or other devices described herein.FIGS. 5-6 illustrate the circuit board assembly 220, including various features that improve the thermal performance of the circuit board assembly 220. As shown in FIG. 5, the circuit board assembly 220 may include one or more covers (e.g., shield structures), such as the covers 500, 502, 504. The covers 500, 502, 504 may be positioned over and at least partially cover and / or enclose circuit components connected to an exterior of the circuit board assembly 220. The covers 500, 502, 504 may be formed from a thermally conductive material, such as a metal. In some cases, the covers are formed of aluminum rather than other metals such as steel, nickel, etc. to provide high thermal conductivity. The covers may absorb heat from the circuit components and spread the heat along the covers (which may occupy a larger area than the circuit components themselves, thereby reducing peak temperatures), and may also help transfer the heat to other structures of the device (e.g., a back cover assembly 273, FIG. 2 ). In some cases, the covers may be attached to a surface of the circuit board assembly 220 that is opposite the surface connected to the chassis portion 219 (e.g., the covers may be attached to a surface that is opposite the rear cover assembly of the device).FIG. 6 illustrates the circuit board assembly 220 with additional thermal components connected thereto. In particular, the circuit board assembly 220 includes a heat diffusion element 506 that is bonded to the top outer surfaces of the covers. The thermal diffusion element 506 may be formed from one or more layers of graphite or other thermally conductive materials and bonded to the covers. The thermal diffusion element 506 may have a thickness between about 10 microns and about 20 microns. The heat diffusion element 506 may be configured to generally receive heat from the covers and spread the heat across the element and optionally transfer heat to other components or structures in the device. The heat diffusion element 506 may be a single element that bridges gaps between multiple metal covers, thereby thermally bonding the multiple covers together and providing a relatively large area for heat diffusion of the covers (as compared to the covers alone).One or more thermal bridges 508 may be positioned on the covers (and on the thermal diffusion element 506, if present) to transfer heat from the circuit board assembly to other components or structures of the device via the covers. For example, the thermal bridges 508- 1, 508- 2, 508- 3 may contact a back cover assembly 273 to transfer heat from the circuit board assembly 220 to the back cover assembly 273. The thermal bridge 508 may be any suitable thermal bond, including a graphite wrapped foam, a thermally conductive loop structure, a thermally conductive paste or gel, a direct metal-to-metal bond, or other suitable thermal bridge.While FIGS. 5-6 use components of device 200 to illustrate various features and concepts, it should be understood that the same features and concepts apply to the corresponding components of device 300 or other devices described herein.FIGS. 7A-7D illustrate various aspects of the battery 230. Although the description uses battery 230 as an example, the same concepts discussed with respect to battery 230 may also be used for other batteries described herein, including battery 330.As mentioned above, the battery 230 may include a conductive battery shell, such as a metallic shell 701, that encloses a battery cell (which may include, e.g., an electrode assembly and an electrolyte). The battery cell may be located within the metallic shell 701. The metallic shell 701 may provide a substantially rigid exterior structure for the battery 230. Compared to a flexible sheath in the form of a film or pouch, the battery sheath can be made of metal with a tighter dimensional tolerance (e.g., less variation in battery size). This can allow the internal components of the battery to be larger, improving the battery capacity and the performance of the device. In this way, the space provided for the battery in the device can also be reduced, so that more space is available for other components of the device or the device can be made smaller. The shell 701 may be formed of stainless steel, aluminum, or other suitable conductive material. In some cases, the shell 701 includes one or more layers for cladding or coating to improve thermal performance. For example, a stainless steel shell 701 may include an aluminum shell (or an aluminum shell may include a stainless steel shell). The aluminum material may improve the thermal performance of the shell 701 due to the higher thermal conductivity of the aluminum compared to the stainless steel.The battery 230 may include first and second conductive connectors 702, 704 to facilitate conductive connection to the cathode of the battery cell (connector 702) and to the anode of the battery cell (connector 704). As described herein, the metallic shell 701 (or another conductive battery shell) may be conductively connected to the anode of the battery cell such that the metal of the shell 701 is at the same potential as the anode (e.g., the shell 701 is at the negative or common voltage potential of the battery 230). In such cases, the first conductive connector 702 (e.g., the cathode) may be conductively insulated from the shell 701.FIG. 7B illustrates an exploded view of the battery 230. As shown, the shell 701 includes an upper shell structure 708 and a lower shell structure 712. The lower shell structure 712 may form a bottom wall and circumferential side walls of the shell 701, and the upper shell structure 708 may form an upper wall of the shell 701. The bottom wall of the shell may be attached to a chassis of a device (e.g., chassis 219, 323), for example, with an adhesive (e.g., an electrically releasable adhesive).The walls of the housing 701 (e.g., the bottom and top walls) may also be configured to transfer the heat from the battery 230 to other components of the device, such as a chassis (e.g., a graphite layer attached to the chassis), a rear cover assembly (e.g., a graphite layer attached to the rear cover assembly), and the like. In some cases, thermal bridges may be positioned between the battery 230 and other devices (e.g., between the lower shell structure 712 and a chassis such as the chassis 219, 323) to transfer heat from the battery 230 to the chassis. The thermal bridges may include graphite-wrapped foams or graphite-coated loops, where the loop or foam structure maintains the graphite (providing thermal conductivity) in contact with the battery 230 and the other structures.In some cases, the shell 701 may include or define one or more tabs. The tabs may protrude from the shell and be connected to other components of the device. In some cases, the tabs form a thermal bond between the shell 701 and other components. Tabs may be used to transfer heat from the battery to other components (e.g., to a chassis of the device) or to transfer heat from other components to the battery. In some cases, the tabs may include attachment features (e.g., through-holes) to facilitate attachment of components to the battery (or attachment of the battery to other components). For example, the tab may be used to attach a component such as a circuit board assembly, a camera, a speaker module, or the like to the battery 230 (or to attach the battery 230 to another component such as a chassis, a chassis, or the like).The upper and lower shell structures 708, 712 may be formed from stainless steel, aluminum, a bimetallic material (e.g., stainless steel and aluminum), or another suitable material. The upper and lower shell structures 708, 712 may have a thickness between about 80 and about 120 micrometers, or between about 95 and 110 micrometers. In some cases, the selected thickness allows the lower shell structure 712 to undergo a deep drawing operation to form the shape of the lower shell structure 712 (e.g., the trough-like shape defined by the bottom wall and the peripheral side walls). For example, selecting the material thickness such that the final thickness of the lower shell structure 712 is between about 95 and about 110 microns may allow the material to be formed without excessive thinning or other structural problems (such as at the inner corner 707 of the L-shaped shell).As shown in FIG. 7B, the battery 230 includes an electrode assembly 710, which may include a rolled electrode configuration, sometimes with reference to a "jelly roll" or a folded or stacked configuration. The electrode assembly 710 can generally be adapted to the shape of the shell 701. Thus, in the illustrated example, both the shell 701 and the electrode assembly 710 may be generally L-shaped. The electrode assembly 710 may be positioned in the case 701, and an adhesive 711 may bond the electrode assembly 710 to the case 701. While FIG. 7B illustrates an adhesive 711 on the top surface of the electrode assembly 710 to adhere to the upper shell structure 708, a similar adhesive may be positioned on the bottom surface of the electrode assembly 710 to adhere to the lower shell structure 712. The adhesive 711 may be a styrene-isoprene-styrene (SIS) adhesive or another suitable adhesive. The adhesive 711 may prevent or inhibit movement of the electrode assembly 710 within the shell 701.The electrode assembly 710 may also include conductive terminals 716, 714 conductively connected to (or defining) the cathode and anode of the electrode assembly 710, respectively. As described in FIGS. 7C and 7D, the conductive terminals 716, 714 may be conductively connected to the conductive connectors 702, 704, respectively, to allow the battery to provide power to external components of the device.To assemble the battery 230, the electrode assembly 710 may be positioned between the upper and lower shells (e.g., in the lower shell structure 712), and the upper and lower shell structures may be sealed. For example, the upper and lower shell structures may be welded together. In the example shown in FIG. 7B, the lower shell structure 712 defines a flange 709, and the peripheral portion of the upper shell structure 708 may be welded to the flange 709 along the entire circumference of the shell 701. During the assembly process, the adhesive 711 (as well as an adhesive on the bottom of the electrode assembly 710) may contact a surface of the shell 701 to bond the electrode assembly 710 to the shell 701.After sealing the shell, an electrolyte (e.g., a liquid, gel, or other flowable material) may be introduced into the shell via an opening 718 formed through the shell. Once the electrolyte is filled, the hole 718 can be sealed with a seal.FIGS. 7C-7D are partial cross-sectional views of the battery 230 as viewed along lines 7C-7C and 7D-7D, respectively, in FIG. 7A. FIGS. 7C-7D illustrate example connections between the conductive terminals of the electrode assembly 710 and the conductive connectors 702, 704.As already mentioned, the conductive terminal 714 (which may be or include a flexible conductive element) of the electrode assembly 710 connected to or defining the anode of the battery (e.g., the minus or neutral pole) of the battery 230 is conductive and physically connected to the shell 701. As shown in FIG. 7C, the conductive terminal 714, which may be conductively connected to one or more electrodes in the electrode assembly 710, is attached to an inner surface of the shell 701 (e.g., an inner surface of the peripheral wall of the lower shell structure 712). For example, the conductive terminal 714 may be welded, soldered, brazed, or bonded with a conductive adhesive. By attaching the conductive terminal 714 to the shell 701 itself, the entire shell 701 may be at the anode potential of the battery (e.g., the negative or neutral connection). The conductive connector 704 may be a conductive pad configured to be physically and conductively connected to other circuit components of the device to provide electrical power to the device. Since the conductive terminal 714 is conductively connected to the shell 701, the conductive connector 704 may be attached to the shell 701 to establish a conductive connection with the conductive terminal 714. For example, the conductive connector 704 may be welded, soldered, or otherwise attached to the shell 701 so as to be conductively connected to each other.FIG. 7D illustrates an example coupling between the conductive terminal 716 (which may be or include a flexible conductive element) connected to or defining the cathode of the battery (e.g., the positive pole). Since the shell 701 is conductively connected to the cathode, the conductive terminal 716 and the conductive connector 702 are conductively insulated from the shell 701. For example, a connector assembly that provides a conductive connection to the conductive terminal 716 may include an internal conductive element 731, the conductive connector 702, an external insulator 730- 1, and an internal insulator 730- 2. The conductive terminal 716 may be conductively connected to the conductive element 731, which may be a metal or other conductive plate within the shell 701. The conductive terminal 716 may be welded, soldered, brazed or otherwise conductively connected to the conductive member 731. The internal insulator 730- 2 is positioned between the conductive member 731 and the inner surface of the case 701 to insulate the conductive member 731 (and thus the conductive terminal 716) from the case 701. The inner insulator 730- 2 may be formed of an electrically insulating or dielectric material, such as a polymer, to provide the conductive insulation.The external insulator 730- 1 may be positioned between the conductive connector 702 and the outer surface of the shell 701. The external insulator 730- 1 may also include a sleeve portion 732 that extends into and / or through a hole 735 in the shell 701 to conductively isolate the surfaces of the holes from the conductive connector 702. The conductive connector 702 may include an extension portion 733 that extends through the hole 735 and is conductively connected to the conductive member 731. The sleeve portion 732 of the external insulator 730- 1 can ensure that the extension portion 733 does not contact the shell 701 in the hole 735, thereby maintaining the electrical insulation of the conductive connector 702 from the shell 701. The extension portion 733 may be welded, brazed, soldered, crimped, or otherwise connected to the conductive connector 731 such that both the conductive connector 702 is conductively coupled to the conductive connector 731 and the conductive connector 702 is attached to the conductive connector 731. By attaching the conductive connector 702 to the conductive member 731, the conductive member 731, the inner insulator 730- 2, and the outer insulator 730- 1 can be effectively clamped, thereby holding the components to the shell 701 and sealing the hole 735.While FIGS. 7A-7D use components of device 200 to illustrate various features and concepts, it should be understood that the same features and concepts apply to the corresponding components of device 300 or other devices described herein.FIG. 8A shows a portion of the device 140, particularly a portion on the back of the device 140, that includes the protrusion 137 that defines the raised sensor array region 163 of the device 140. The back cover 154 further defines a first hole 159 through the protrusion 137 in the raised sensor array region 163 and a second hole 160 through the protrusion 137 in the raised sensor array region 163. A first lens of a first camera 138 extends at least partially into the first hole 159 and a second lens of a second camera 139 extends at least partially into the second hole 160.The device 140 also includes a flash 136 (which may be or include a flash module) that is at least partially within the device housing and positioned outside the raised sensor array region 163 and extends at least partially into a third hole 162 (e.g., a flash hole) defined by the back cover 154 outside the raised sensor array region 163.The rear cover 154 also includes a fourth hole 135 corresponding to a microphone terminal (e.g., the microphone terminal 135). The fourth hole 135 is defined by the protrusion 137 in the raised sensor array region 163, and a microphone module is acoustically coupled to the fourth hole 135.The camera lenses, the flash and the microphone connection can be arranged in a specific alignment with respect to one another. For example, the first hole 159 and the second hole 160 (for the cameras) are aligned in a first direction (e.g., parallel to the lateral side of the phone), parallel to the y-direction), and the third hole 162 and the fourth hole 135 (for the flash and the microphone) are aligned in a second direction perpendicular to the first direction (e.g., perpendicular to the y-direction and / or parallel to the x-direction). In addition, the third hole 162 is equidistant from the first and second holes 159, 160 and the fourth hole 135 is also equidistant from the first and second holes 159, 160. The orientation and positioning of the third and fourth holes in this manner with respect to the cameras (e.g., the first and second holes 159, 160) may provide optical and acoustic performance advantages. For example, the flash light may have substantially the same or uniform illumination patterns for each of the cameras, and the microphone port has the same or similar relative position to each of the cameras, thereby providing the same or similar illumination and audio capturing power during imaging with one of the cameras.As described herein, although the microphone port 135 is positioned in the raised sensor array region 163, the microphone module that receives the sound via the microphone port is positioned outside the raised sensor array region 163 (e.g., below a portion of the back cover 154 that is outside of the protrusion 137). Accordingly, the device 140 may include a bracket 158 connected to the rear cover 154 (e.g., at an interior of the rear cover assembly) and at least partially defining an acoustic waveguide 164 configured to acoustically couple the microphone module 165 (FIG. 8D ) to the fourth hole 135. The acoustic waveguide thus allows the terminal 135 of the microphone to be located in the elevated sensor array region 163, while the microphone itself may be remote from the elevated sensor array region 163. Because the cameras are below the raised sensor array region 163, there may not be enough space within the device to also house the microphone module in the raised sensor array region (without increasing the thickness of the device in the z-direction). Accordingly, acoustic waveguide 164 may allow placement of microphone port 135 in raised sensor array region 163 without increasing the size or thickness of device 140. While the present example describes an acoustic waveguide for acoustically coupling a hole in the raised sensor array region to a microphone module that is remote from the raised sensor array region, the same or similar construction may be used for acoustically or fluidly coupling a hole in the raised sensor array region to other remote components. For example, a pressure sensor may be located remote from the raised sensor array region and fluidly coupled to a hole in the raised sensor array using the same or similar components and techniques described herein (e.g., the acoustic waveguide may serve to fluidly couple the hole to the pressure sensor). As another example, a remote barometric venting system may be fluidly connected to a hole in the raised sensor array. Other components are also conceivable.FIG. 8B illustrates the portion of the device 140 mounted in FIG. 8A with the rear cover assembly removed. As shown in FIG. 8B, the device 140 includes a rear facing camera assembly 170 positioned at least partially within the housing of the device 140. FIG. 8C illustrates a perspective view of the camera assembly 170. The camera assembly 170 includes a first lens assembly 167 that extends at least partially into the first camera hole 159 (FIG. 8A ) and a second lens assembly 168 that extends at least partially into the second camera hole 160 (FIG. 8A ). The camera housing 166 may be formed of metal or other suitable material and support the first and second camera assemblies as well as other camera components including image sensors, optical components, circuitry, etc.The camera housing 166 may include a recess 169 along a side of the camera housing 166 to receive a portion of a shroud 171 of the microphone module. As mentioned above, the microphone module for the rearward facing sensor array may be positioned outside the raised sensor array region, but acoustically coupled to a microphone port in the raised sensor array region. To house the microphone module near the microphone port, the camera housing 166 defines the depression 169 such that the trim 171 may extend into the depression and at least partially overlap with the camera housing 166.The depression 169 may generally be between the cameras of the camera assembly 170 and may extend only a portion of the thickness of the camera housing 166. In particular, the non-recessed region 173 or the corner of the camera housing 166 may be occupied by components of the cameras, and thus the recess may be limited to a portion of the depth of the camera housing 166. The depression 169 may also provide z-direction clearance between the shroud 171 and the camera housing 166 such that when the device is subjected to an impact or other force, the forces are not directly transmitted through the shroud 171 to the rear cover (e.g., through contact between the shroud 171 and the camera housing 166).The camera housing 166 may also form a recessed region 172 around the second camera assembly 168. The recessed region 172 may be recessed along the outer surface of the camera housing 166 relative to the region 174 about the first lens assembly 167. In some cases, the camera housing 166 may be thinned in the region 174 to allow the camera module to be positioned within the camera housing 166 closer to the rear cover assembly, which may result in the first lens 167 further extending into the first hole 159 in the rear cover and thus allowing use of a thinner camera cover (as compared to a housing without the thinned wall).The recessed region 172 and the non-recessed region 174 may form substantially planar surfaces that extend entirely around the second and first lens assemblies, respectively, to provide a continuous planar surface upon which gaskets may be positioned. The gaskets may provide a light and environmental seal to the camera housing 166 and / or the lens assemblies. The seals may abut or seal against an interior side of the rear cover assembly. The gaskets may be made of or include foam, adhesive or other deformable material.FIG. 8C also shows a flexible circuit element 802 operatively connecting one or more of the cameras of the rearward facing camera assembly 170 (e.g., a first camera associated with the first lens assembly 167 and / or the second camera associated with the second lens assembly 168) to a processing system of the electronic device (e.g., to a circuit board assembly with a processor or to another processing system). The flexible circuit element 802 may extend along a side of the camera housing 166, particularly along the side of the camera housing 166 defining the recess 169. The flexible circuit element 802 may define a notch 804 that aligns with the recess 169 (e.g., that conforms to a perimeter of the recess 169 or does not hide or cover the recess 169 from the side). The notch 804 therefore provides clearance at the location of the recess 169 to allow the trim 171 to protrude into both the recess 169 and the notch 804. Traces or other conductive elements in the flexible circuit element 802 may be routed through the flexible circuit element 802 along one side of the notch 804 (e.g., through the portion of the circuit substrate defining the notched region).FIG. 8D illustrates a portion of the rear cover assembly positioned over the rearward facing camera assembly 170. The rear cover assembly includes the rear cover 154 and a camera cover 180 covering the first lens assembly 167 and a camera cover 179 covering the second lens assembly 168. Also shown are the gaskets 177, 178 that seal against the recessed region 172 and the non-recessed region 174, as described above.FIG. 8D also illustrates an example of the microphone module 165, the flash module 187, the trim 171, and the bracket 158 connected to an inner surface of the rear cover 154. The trim 171 may at least partially cover the flash module 187 and the microphone module 165 and at least partially structurally connect the flash module 187 and the microphone module 165 to the rear cover 154.As mentioned above, the mount 158 defines an acoustic waveguide 164 that acoustically couples the microphone port 135 to the microphone module 165. FIG. 9 illustrates a single view of an example bracket 158. The bracket 158 may include or define a base 184 and a continuous wall 183 extending from the base 184. The bracket 158 may also include a hole 181 that acoustically connects to the microphone module 165. The bracket 158 may further include a hole 186 through which a flash module may extend at least partially (and / or through which the flash may emit light). The flash module 187 may also be connected to the bracket 158 (e.g., by adhesives, fasteners, mechanical bonds, etc.).The continuous wall 183 may abut the back cover (or back cover assembly) to define the acoustic waveguide 164 between the base 184 and the back cover (or another component of the back cover assembly). For example, the continuous wall 183, when abutting the back cover, defines a channel or tunnel that acoustically couples the microphone port 135 to the microphone module 165. For example, FIG. 9 illustrates an example acoustic path 182 defined by acoustic waveguide 164. In this example, acoustic path 182 extends through the microphone port, into a first end of acoustic waveguide 164, through the channel or tunnel formed by wall 183, base 184, and back cover (or other back cover component), and through hole 181 at a second end of the acoustic waveguide (opposite the first end) and to microphone module 165.In some cases, a compliant material, adhesive, or other sealing element may be positioned along the top of the wall 183 or otherwise disposed between the top of the wall 183 and the rear cover assembly. The compliant material, adhesive, or other sealing element may seal the acoustic waveguide, thus reducing acoustic attenuation or loss or other acoustic interference or problems. The bracket 158 may be mounted from a polymer, metal, or other suitable material (including combinations or compositions of various materials).FIG. 10A is a partial cross-sectional view of a housing component 1000 having a shrouded construction. The housing component 1000 may correspond to any housing described herein and / or any housing component described herein that may include a casing, such as the housing components 124, 125, 126, 127, 128, and 130 of the device 100, or the housing components 211, 212, 213, 214, 215, or 216 of the device 200, or the housing components 312, 313, 317, 315, 316, or 319 of the device 300. FIG. 10A may generally conform to a view taken along line 10A- 10A in FIG. 4A.The housing component 1000 may include a core portion 1002 and a sheath portion 1004. The core portion 1002 may be directly bonded to the enclosure portion 1004. The housing component 1000 may be formed into a precursor material for the cladding by co-extrusion of the core portion 1002 and the cladding portion 1004. In the clad precursor material, the core portion 1002 and the cladding portion 1004 may be fused or otherwise joined together. The fusion may occur along an interface (which may be within the volume of the plated element). The fusion may be characterized by a diffusion bond between the core portion 1002 and the cladding portion 1004 at the interface.The precursor material may then be formed into the housing component 1000 (e.g., an extrudate member) in various processes. For example, the precursor material may be forged and / or machined to determine the overall shape and mechanical characteristics of the package component 1000, and then subjected to polishing, patterning, and / or coating operations. The mechanical features may include locking features for locking to connection structures (e.g., for mechanically coupling housing components), fastening features (e.g., holes for receiving fasteners), surfaces, antenna feed and ground points, and the like.The enclosure portion 1004 may form an outer surface 1003 of the housing component 1000. The core portion 1002 may form an inner surface of a device and / or a housing (e.g., a surface that is not external or visible from the outside of the finished device).The outer surface defined by the enclosing portion 1003 may have a surface structure that creates a specific visual appearance and / or a specific haptics. For example, the surface texture may include a texture that creates diffuse reflections. The surface texture may be created by grinding, lapping, machining, ablation, blasting (e.g., sandblasting, pearlescent), etching (by mechanical etching, laser etching, chemical etching, or the like), or any other suitable texturing method. The outer surface 1003 may also include a coating, such as an applied coating. The coating may be applied to the package components by plasma vapor deposition (PVD), chemical vapor deposition (CVD), or the like. In some cases, the enclosure portion 1004 is polished (before and / or after coating).The core portion 1002 may be made of aluminum (e.g., an aluminum alloy) and the cladding portion 1004 may be made of titanium (e.g., a titanium alloy). In some cases, core portion 1002 is made of aluminum and cladding portion 1004 is made of stainless steel. Other materials are also conceivable for the core and sheath sections.Each of the core portion 1002 and the enclosure portion 1004 may define a portion of mounting surfaces 1006 and 1008 on which a front cover assembly and a rear cover assembly may be mounted, respectively. For example, a frame member of a front cover assembly (connected to a front cover) may be secured to the surface 1006 with an adhesive. As another example, the front cover may be directly attached to the adhesive. Similarly, a back cover may be secured to the surface 1008 with an adhesive. In some cases, a rear cover assembly includes a frame member or other component, and the frame member is secured to the attachment surface 1008 using the adhesive.The enclosure portion 1004 may also form a flange or lip portion 1010 that extends around and at least partially covers the side of a front cover and a flange or lip portion 1012 that extends around and at least partially covers the side of a rear cover. In some cases, the flanged or lip portions 1010, 1012 are substantially flush with the outer surfaces of the front and rear covers. In some cases, the flange or lip portions 1010, 1012 are defined only by the enclosure portion 1004, while in other cases, they are at least partially defined by the core portion 1002.FIG. 10A also shows an example structure for inhibiting or preventing galvanic corrosion in the area of a through hole 1017 extending through the wall segment defined by the housing component 1000. The through hole 1017 may be a hole for a key as shown, but the same or similar construction described herein may also be used with holes for charging ports, speakers, SIM card trays, microphones, dials, or the like. As described herein, the through-hole may be formed by drilling a hole through a core portion 1002 to expose a surface of the enclosure portion 1004, adding material within the hole (e.g., by fusing the material to the exposed enclosure surface), and then removing a portion of the added material (e.g., by drilling a hole into the added material) to form the through-hole, as well as a liner structure 1014 that remains fused to the enclosure portion 1004. Since the liner structure 1014 is made of the same material as the enclosure portion 1004, the risk of galvanic corrosion at the seam 1024 or the interface between the enclosure portion 1004 and the liner structure 1014 within the through hole is low or eliminated. Moreover, the configuration of the liner structure 1014 results in the seam 1024 being positioned between the various metals of the core portion 1002 and the seal portion 1004 (and the enclosure structure 1014) within the interior environmentally sealed interior volume of the device, rather than along the interior surface where it may contact water, moisture, or other liquids or contaminants. As described herein, this configuration may help prevent or inhibit the occurrence of galvanic corrosion at the seam 1024 between the material of the core portion 1002 and the material of the cladding portion 1004 and / or the liner structure 1014. In some cases, the core portion 1002 and the sheath portion 1004 may be in contact at the seam 1024. In such cases, a metallurgical bond may or may not be present at the seam 1024. In some cases, a gap may be present at the seam 1024 (e.g., the core portion and the sheath portion may be adjusted apart at the seam 1024).As shown in FIG. 10A, the enclosure portion 1004 defines a portion of an outer surface of a device and a first portion 1015 of the through hole 1017. The core portion 1002 connected to the enclosure portion 1004 defines a counterbore 1018 along the inside of the housing component 1000. Counterbored bore 1018 extends through core portion 1002 to sheath portion 1004 and aligns with through hole 1017. For example, counterbored hole 1018 may be concentric with through hole 1017. In other cases, counterbored hole 1018 need not be concentric with through hole 1017. In particular, counterbored hole 1018 may be provided such that liner structure 1014 may be fused to casing portion 1004 along a ledge or ledge of casing portion 1004 (e.g., where fusion region 1020 is located), as illustrated in FIGS. 10C-10D. Thus, counterbored hole 1018 may have any suitable shape that allows the material of liner structure 1014 to be fused to casing portion 1004.The liner structure 1014, which may be formed by a metal deposition and machining process as described herein, is positioned in the counterbored hole 1018 and defines a second portion 1019 of the through hole. As described herein, the liner structure 1014 may be made of the same material as the enclosure portion 1004 and may be fused to the enclosure portion 1004 in a fusion region 1020. Thus, the liner structure 1014 is illustrated in FIG. 10A by a stippling to distinguish the liner structure 1014 from the enclosure portion 1004.The fusion region 1020 may define a third portion of the through-hole 1017 that is between the first portion 1015 of the through-hole and the second portion 1019 of the through-hole. Thus, as described herein, the hole surface of the through hole may be a through hole surface partially defined by the enclosure portion 1004, the fusion region 1020, and the liner structure 1014. In particular, the enclosure portion 1004 defines a first portion of a hole surface of the through hole 1017, the liner structure 1014 defines a second portion of the hole surface of the through hole 1017, and the fusion region 1020 between the enclosure portion 1004 and the liner structure 1014 defines a third portion of the hole surface of the through hole 1017. As described herein, the through hole surface of the through hole 1017 may be a machined surface formed by drilling or otherwise machining a hole through the enclosure portion 1004 and through the metal material fused to the enclosure portion 1004 (and from which the liner structure 1014 is formed).Because the cladding portion 1004, the fusion region 1020, and the liner structure 1014 are made of the same material (e.g., a titanium alloy), the via hole surface is not exposed to or otherwise resistant to galvanic corrosion that may occur when water or other liquids or contaminants are present in the via hole 1017. In particular, the formation of the hole using the liner structure shown and described herein may define a surface of a single material along an interface with which liquid may contact. In this way, the liquid entering the hole does not contact a seam between the various materials of the core and sheath section. For example, a component such as a button, a SIM tray, a speaker, or the like may protrude into the through hole 1017. For example, an input member (e.g., a button) may form a shaft that extends into the through hole 1017. A seal member 1021 may be positioned in the through hole 1017 and may be positioned against the shaft and the hole surface to form a seal against the liner structure 1014. The sealing element may form a seal between a sealed interior of the device and an external environment and inhibit the ingress of liquid or moisture into the sealed interior of the device (where a seam 1024 may be exposed between the core and cladding materials). Accordingly, the liquid is in the outer region where there is no exposed seam between the core and sheath portions. In other words, this configuration positions the seam 1024 between different metallic materials within the sealed interior volume of the device such that the seam is less likely to contact liquids or moisture and is therefore less likely to be subject to galvanic (or other) corrosion.FIGS. 10B-10E illustrate the stages of an example process for forming a housing component, such as the housing component 1000, with a fused liner structure defining a portion of a through-hole. FIG. 10B illustrates a sheath precursor 1025 that includes the sheath portion 1004 fused to the core portion 1002. As described herein, the enclosure portion 1004 and the core portion 1002 may be fused together via a diffusion bond along an interface 1026. The diffusion bond may be formed during an extrusion process as described herein.As shown in FIG. 10C, a counterbored hole 1018 may be formed in the core portion 1002. Counterbored hole 1018 may extend fully to casing portion 1004 and expose a surface 1028 of casing portion 1004. In other words, counterbored hole 1018 may be a blind hole in which at least the bottom surface of the blind hole is defined by sheath portion 1004.As shown in FIG. 10D, after the counterbored hole 1018 is formed, the material 1029 may be melt bonded to the enclosure portion 1004 within the counterbored hole 1018 along the surface 1028. For example (described in more detail in FIG. 10F ), the material 1029 may be deposited on and fused to the enclosure portion 1004 via a laser-based direct metal deposition process (where a laser is used to melt a base material and fuse the base material to the enclosure portion 1004), thereby forming a fusion region 1030 at the interface between the enclosure portion 1004 and the material 1029. The fusion region 1030 may correspond to a region where the material of the enclosure portion 1004 and the material 1029 are fused and resolidified. As described herein, the enclosure portion 1004 and the material 1029 may be made of the same metal and / or metal alloy or otherwise formed from materials (e.g., metals) that have a lower potential for galvanic interactions or corrosion. As an example, the enclosure portion 1004 and the material 1029 may be or include titanium.While the material 1029 is fused to the enclosure portion 1004 by direct metal deposition, in some cases the material 1029 (and thus the liner structure formed from the material 1029) may also be fused to the core portion 1002. For example, due to the heat supplied to the material 1029 during the deposition and fusion of the material 1029 with the casing portion 1004, the material 1029 may also be fused to the core portion 1002 along the hole surface of the counterbored bore 1018 (e.g., the material 1029 and the material of the core portion 1002 are sufficiently fused and fused to form a solid structure consisting of a mixture of both materials). In other cases, the material 1029 may not fuse with the core portion 1002. For example, in some cases, the material 1029 may be in contact with the core portion 1002, but may not be fused to the core portion 1002. In other examples, the material 1029 and the core portion 1002 may be separated from each other by a gap.After the material 1029 is deposited and fused to the sheath portion 1004 (and optionally at least partially to the core portion 1002), the through hole 1017 is formed through the sheath portion 1004 and the added material 1029. The through hole 1017 may be formed by a machining process such as drilling or milling, thereby creating a continuously machined surface of the through hole (e.g., a continuously machined surface defined along the enclosure portion 1004, the fusion region 1020, and the liner structure 1014).FIG. 10E illustrates the package component 1000 after the formation of the through hole 1017. As shown and described herein, the enclosure portion 1004 defines a first portion 1015 of the through-hole 1017. The core portion 1002 defines the counterbored hole 1018 along the inside of the housing component 1000. The liner structure 1014 is positioned in the counterbored bore 1018 and defines a second portion 1019 of the through-hole 1017. The liner structure 1014 may be made of the same material as the enclosure portion 1004 and fused to the enclosure portion 1004 in a fusion region 1020 (which may be a remaining portion of the fusion region 1030), and the fusion region defines a third portion of the through hole 1017. Thus, as shown, the hole surface of the through hole 1017 may be a through hole surface defined in part by the enclosure portion 1004, the fusion region 1020, and the liner structure 1014.FIG. 10F illustrates an example laser-based deposition process in which material 1029 is ultimately deposited in counterbored hole 1018 and fused to enclosure portion 1004. As shown, a fill material 1031, which may be the same material as the casing portion 1004 or another material that does not substantially undergo galvanic interaction with the material of the casing portion 1004, may be introduced into the counterbored hole 1018, and a laser beam 1032 (e.g., an annular laser beam) may be directed into the counterbored hole 1018 such that the fill material 1031 is melted and deposited in the counterbored hole 1018. During this process, the laser beam 1032 causes the cladding portion 1004 to at least partially melt along its surface such that the molten material 1031 fuses with the molten surface of the cladding portion 1004 (e.g., at the interface between the fill material 1031 and the cladding portion 1004). The filling material 1031 may be introduced into the laser beam through the center of the ring-shaped laser beam. In this process, the counterbored hole 1018 may be filled with the molten fill material to form the deposited material 1029, as shown in FIG. 10D. Counterbored hole 1018 may be filled with the filler material alone. After the molten filler 1031 is introduced into the counterbored hole 1018, it is allowed to solidify again to form the solid material portion 1029 (shown in FIG. 10D ). FIG. 10F illustrates the laser-based deposition process in a portion of the deposition process where the material 1033 (e.g., a portion of the material that ultimately forms the added material 1029 in FIG. 10D ) has already been introduced into the counterbored hole 1018 by melting the fill material 1031 with the laser beam 1032.FIGS. 11A-11B illustrate another example technique for filling a counterbore hole in a core portion to structure a liner structure as shown and described herein. FIG. 11A illustrates a sheath precursor 1100 that includes a sheath portion 1104 and a core portion 1102. A counterbored hole 1101 is inserted through the core portion 1102 into the casing portion 1104 and exposes a surface 1105 of the casing portion 1104. In some cases, a hole 1107 may also be formed through the cladding portion 1104. An insert 1106 is positioned in counterbored hole 1101 and on the exposed surface 1105 of sheath portion 1104. The insert 1106 may be formed of the same material as the cladding portion 1104 (e.g., a titanium alloy). The insert 1106 may be welded to the enclosure portion 1104. For example, the insert 1106 may be laser welded (represented by laser beams 1103) to the enclosure portion 1104. The welding process may result in a fusion region 1109 (FIG. 11B ) at the surface 1105, where the insert 1106 is fused to the enclosure portion 1104. As shown, the insert 1106 includes a flange at the top of the insert 1106 (e.g., forming the upside-down hat shape in FIG. 11A ), although in other cases the insert 1106 may include a cylindrical shape (e.g., without a flange) or another suitable shape that facilitates filling the counterbore hole 1101.FIG. 11B illustrates the casing precursor 1100 after welding the insert 1106 to the casing portion 1104 in the counterbored hole 1101 and after forming a through hole 1108 through the insert 1106 (e.g., by machining as described herein) to pattern a liner structure 1111. Similar to the structure resulting from the technique of metal deposition described in FIGS. 10B-10E, the technique illustrated in FIGS. 11A-11B results in a package in which a continuous machined surface is defined along the enclosure portion 1104, the fusion region 1109, and the liner structure 1111. In other words, the cladding portion 1104, the fusion region 1109, and the liner structure 1111 each define a portion of the through hole 1108 through the precursor 1100 (which is ultimately formed into a package component).As described herein, package components of a package of an electronic device may be used as radiation structures for wireless communication devices. In some cases, the emissive portions of the package components may be affected by the presence of nearby conductive materials. For example, other metal structures located near the radiating portions may interfere with (e.g., capacitively couple) the radiating portions, which may degrade antenna performance. FIGS. 12A-12B illustrate example configurations of the housing and front cover assembly that mitigate or reduce the effect of nearby conductive components on the radiating portion.FIG. 12A illustrates a front view of an example electronic device 1200, which may be or corresponds to an embodiment of an electronic device described herein. The device 1200 may include a housing 1202 (which, as described herein, may include multiple interconnected housing components) and a front cover assembly 1206 connected to the housing 1202. The front cover assembly 1206 may include a support frame 1208 that is part of the display stack and is connected to a front cover of the front cover assembly 1206. In some cases, the support frame 1208 may be a metal structure defining a flange and at least partially encapsulated in a molded polymer frame connected to the front cover and extending around the periphery thereof. The molded polymeric frame may provide structural rigidity to the front cover assembly and define a mounting surface that serves to attach or otherwise connect the front cover assembly to the housing 1202. For example, the frame member may have an upper surface connected to the front cover and a lower surface connected to the housing. The top surface may be joined by directly adhering the molded polymeric material to the front cover (as well as by mechanically engaging features of the display stack, such as the support frame 1208), and the bottom surface may be joined to the housing by an adhesive (e.g., a heat sensitive adhesive, a pressure sensitive adhesive, etc.). The molded polymeric material may be molded using a low pressure overmolding process in which a front cover is positioned in a device defining a mold cavity around the support frame 1208 and a flowable material is introduced into the mold cavity. The flowable material is then cured or otherwise cured to form the polymer frame.In some cases, the proximity of the support frame 1208 to the radiating portions of the housing 1202 may negatively affect (or otherwise interfere with) the performance of the radiating portions. Accordingly, the support frame 1208 and the housing 1202 may be configured with strategic depressions, protrusions, thinned regions, and full thickness regions that maintain proper physical separation between the radiating portions and the support frame 1208 while maintaining the strength of the housing at particular locations.For example, in some cases, the corners of the housing 1202 are used as radiating structures. Accordingly, it is advantageous for the antenna performance to increase the distance between these portions of the housing 1202 and the corners of the support frame 1208. However, the housing corners are also prone to crashes or other impacts, and it may not be advantageous to reduce the thickness of the housing in the corners to achieve a desired physical separation from the support frame 1208. Accordingly, as shown in FIG. 12A, the support frame 1208 may define recessed regions 1210 (e.g., 1210- 1 to 1210- 4) near the corners of the housing 1202. The recessed regions 1210 may be recessed relative to the portions 1211 of the support frame that occupy the entire width (or are wider). The recessed regions 1210 present the support frame 1208 a target distance (e.g., distance D 1 in FIG. 12A ) from the housing 1202, maintaining the full thickness of the housing 1202 in the corner region.In areas of the housing 1202 where strength is less important or where less material may be used to provide sufficient strength (e.g., off the corners), the housing 1202 may be thinned to define thinned regions 1214, while the support frame 1208 may have a greater flange width in these areas. Thus, the support frame 1208 and the adjacent portion of the housing 1202 may be adjusted a target distance (e.g., distance D 2 in FIG. 12A ) from each other. By using combinations of recessed regions 1210 on the support frame 1208 and thinned regions 1214 of the package 1202, the distance between the support frame 1208 and the package 1202 in different regions may be substantially the same (e.g., the distances D 1 and D 2 may be the same or substantially the same, e.g., within about 10%, while accommodating different structural requirements of the device). For example, at higher strength (or more material of the housing) the housing 1202 may have the full thickness and the support frame 1208 may have a recessed region, and at lower strength (or less material of the housing), the housing 1202 may have a thinned region and the support frame 1208 may have a larger flange width. Combinations of complementary thin housings and full-size support frames (and vice versa) can be positioned at various locations around the device, as shown in Figure 12A.FIG. 12B illustrates a perspective view of a portion of the housing 1202 as viewed along line 12B- 12B in FIG. 12A. The portion of the housing 1202 shown in FIG. 12B may define at least a portion of an antenna radiator as described herein. As shown, the housing 1202 includes a rim portion 1216 (also referred to as a flange or lip portion in some cases) positioned adjacent a portion of a front cover assembly when the front cover assembly is secured to the housing 1202. The rim portion 1216 defines a first region 1204- 2 having a first thickness (e.g., the full thickness or the greatest thickness of the rim portion) and a second region 1214- 2 (e.g., a thinned region) having a second thickness less than the first thickness. The thinned region 1214- 2 may be formed by forging, machining, or other suitable process. (FIG. 12A also illustrates a region 1204- 1 having a first thickness (e.g., the full thickness or the greatest thickness of the rim portion) and a second region 1214- 1 (e.g., a thinned region) having a second thickness that is less than the first thickness).The devices described herein may include buttons that include several different functions for sensing, pressure sensing, and tactile feedback. For example, such buttons may include a touch sensor that senses touch inputs along an exterior surface of the button (e.g., an input surface), a force sensor (e.g., a strain-based force sensor) that senses or determines the force of an input to the button, and a tactile switch that is actuated when the button is pressed with a sufficient force or threshold. The tactile switch may also provide tactile feedback to indicate when the input has actuated the tactile switch. However, since the button is also associated with a force sensor, the button may be associated with other actuation points, thresholds, or states (e.g., a "half press") that may cause the device to perform certain actions different from those performed in response to actuation of the tactile switch. To indicate that such actuation points have been met, the device may include haptic output using a built-in haptic actuator (e.g., a device-wide haptic actuator, such as haptic actuators 222, 322 in FIGS. 2, 3, or a separate haptic actuator, such as a dedicated haptic actuator for one or more buttons). Further, as mentioned above, the key may include a touch sensor to sense inputs by touch (and optionally by gestures). Such touch inputs may result in the device performing other actions different from those initiated by half-pressing (or other partial pressing) and full pressing (e.g., actuation of the tactile switch). In addition, touch inputs can also be associated with or trigger haptic outputs of an installed haptic actuator. Thus, the button is capable of making multiple different types of inputs to control multiple different types of device functions (or initiate device actions), and is also capable of providing different tactile or haptic outputs in response to the different inputs.FIG. 13A illustrates a partial cross-sectional view of a device 1300 having an input key system 1304 (also referred to herein simply as key 1304) as viewed along line 13A- 13A in FIG. 1A. The key 1304 may be or correspond to an embodiment of the keys 121, 155 or other keys described herein (e.g., the keys 116, 118, 120, 152, 156, 157, 285, 385). As described herein, the button 1304 may include a touch-sensitive input surface to sense touch and optionally gesture inputs, as well as both a force sensor and a tactile switch to sense various types of force inputs.As shown in FIG. 13A, the button 1304 is positioned along a side of the device 1300. For example, the device 1300 may include a housing component 1302 defining a side of the device 1300, and the button 1304 (and / or an input structure 1305 of the button 1304) is positioned in an opening 1307 defined by the housing component 1302. In some cases, an input surface of the input structure 1305 (e.g., an outer surface of the input structure 1305 configured to receive user inputs including touch inputs, gesture inputs, force or translation inputs, and the like) is substantially flush with (and optionally with a depression relative to) the lateral outer surface of the housing component 1302. In this way, inadvertent actuations of the button 1304 may be reduced or avoided.The input structure 1305, and generally the button 1304, may be configured to receive and capture various types of input. For example, the button 1304 may include a touch sensor for sensing touch inputs (e.g., touches, taps, gestures, etc., as described herein), as well as a switching element configured to be actuated in response to a force that satisfies a certain force threshold. The button 1304 may also include a force sensor system responsive to a force input that satisfies one or more force thresholds that are different from those of the shift element. Thus, the button 1304 may be responsive to a first force input satisfying a first force threshold (e.g., as detected by a force sensor system), a second force input satisfying a second force threshold different than the first force threshold (e.g., corresponding to actuation of a shift element), and a touch input (e.g., as detected by a touch sensor system). Additionally, in some cases, the button 1304 (or the device generally) may be responsive to combinations or sequences of inputs. For example, the device may be responsive to changes in force input after an actuator is actuated (or another force threshold is reached). As a specific example, the device may initiate a video capture mode in response to an input actuating a switching element. After the video capture mode is initiated and until the key is released, changes in the force applied to the key may alter the zoom of the camera (e.g., a greater force may zoom in the camera and a lesser force may zoom out the camera). Once the key is fully released, the power zoom operation can be terminated and other operations can be initiated (e.g., termination of video capture) by subsequently depressing the key. Generally, the degree of force sensed by a force sensing system may be correlated with the degree, magnitude, or other characteristic of an action to be performed by the device. For example, a stronger press may result in a higher scroll speed of a displayed list (e.g., when the key input is used to control scroll functionality) or a higher rate of volume change (e.g., when the key input is used to control output volume).The input structure 1305 may include a sensing element 1308 and a touch element 1310 coupled to the sensing element. A cover 1306 may be positioned over the touch-sensitive element 1310 and define the input surface of the input structure 1305. The sensing element 1308 may include a chassis portion 1317 and posts 1318-1, 1318-2 extending from the chassis portion. The first post 1318-1 may extend through a first through hole in the housing component 1302, and the second post 1318-2 may extend through a second through hole in the housing component 1302. At least one of the posts (e.g., posts 1318-2) may be hollow or otherwise define a passage through which a flexible circuit element 1320 (or other conductive coupler) may extend. The flexible circuit element 1320 may operatively couple the touch sensitive element 1310 to a processing system (optionally via one or more additional flexible circuit elements or other conductive couplers).Sealing members 1324 (e.g., O-rings) may be positioned around the posts 1318 to form a seal between the posts 1318 and the housing.In some cases, a potting material 1322 at least partially fills the hollow post 1318-2 and encapsulates at least a portion of the flexible circuit element 1320 within the hollow post 1318-2. Potting material 1322 may also at least partially fill a volume defined between cover 1306 and sensing element 1308 and at least partially encapsulate touch-sensitive element 1310 (and / or other circuitry or components in input structure 1305). The potting material 1322 may be an adhesive, epoxy, or other polymeric material and may flow into the sensing element 1308 and then cure or otherwise cure to encapsulate the flexible circuit element 1320.The button 1304 further includes a beam structure 1312 that is at least partially within the shell. The beam structure 1312 can be attached to the housing component 1302 along an inner side or surface of the housing component 1302. For example, the beam structure 1312 may be secured to the housing component 1302 via fasteners 1326 (e.g., screws). FIG. 13A illustrates the first and second fasteners 1326-1, 1326-2, and FIG. 13B illustrates a third fastener 1326-3 (which may not be visible in the particular cross-section shown in FIG. 13A ).The beam structure 1312, or a portion thereof, may be configured to deflect as a result of a force input applied to the sensing element 1308. The button 1304 further includes a strain sensing element 1316 (or other element or system for sensing deflection) connected to the beam structure 1312. The strain sensing element 1316 may include one or more strain gauges (e.g., a Wheatstone bridge) or other strain or deflection sensing elements that generate a signal that changes (e.g., continuously changes) based on the amount of deflection of the beam structure 1312. Other examples of strain or displacement sensors may include, without limitation, piezoresistive sensors, piezoelectric sensors, capacitive strain sensors, optical strain sensors, fiber Bragg grating strain sensors, magnetostrictive sensors, and the like. Because the amount of deflection of the beam structure corresponds to the amount of force applied to the sensing element 1308, the signal from the strain gauge 1316 may be used to determine a characteristic of a force applied to the sensing element 1304. In some cases, additional strain gauges may be positioned on the beam structure 1312 or other deflectable structure of the button.The beam structure 1312 may be formed from metal (e.g., aluminum, stainless steel, metal alloys, etc.) or another suitable material (e.g., a polymer, reinforced polymer, etc.) that provides target flexibility to facilitate strain sensing by the strain sensing element. In some cases, the beam structure 1312 may be formed by metal injection molding, machining, forging, or other suitable processes and / or combinations of processes.The device 1300 may determine whether an input applied to the sensing element 1308 satisfies one or more conditions using the strain sensing element 1316 (and associated processing systems and / or circuitry). For example, the device 1300 may determine whether the input satisfies a condition indicative of a particular force or deflection of the beam structure 1312 (e.g., a threshold deflection or threshold force). As another example, the device may determine whether the input satisfies a condition indicating that the tactile element 1308 has been pressed at a particular distance (of one or more possible distances). As another example, the device may determine whether the input satisfies a state of duration (e.g., the input has been detected for at least a certain duration). The states may be single-factor states (e.g., a force or deflection condition) or multi-factor states (e.g., a force and duration condition, such as sensing an input force for a particular duration). In response to detecting that the input satisfies the condition, the device may perform an operation (e.g., change the volume of audio output, switch between audible and silent modes, disable a screen, place the device in a "sleep" mode, or the like).The button 1304 also includes a switching element 1327 (e.g., a dome switch) connected to the beam structure 1312 and configured to collapse in response to the button input applied to the button 1308 satisfying a force threshold. Because the button 1304 includes both the switching element 1327 and the strain gauge 1316, the button 1304 may be responsive to force inputs that meet multiple different thresholds. For example, the button 1304 (and / or the device 1300 generally) may be responsive to a first force input that satisfies a first force threshold (e.g., as detected by the strain gauge 1316) and a second force input that satisfies a second force threshold that is different than the first force threshold (e.g., as detected by the switching element 1327 being actuated). Further, the device 1300 may perform different operations in response to sensing the various force inputs. For example, the device may perform a first operation when it determines with the strain sensing element 1316 that the force input satisfies the first force threshold and may perform a second, different operation when it determines (e.g., based on actuation of the switching element 1327) that the force input satisfies the second force threshold. As described herein, the device may perform a third, different operation in response to detecting a key input with the touch-sensitive element 1310, and may further perform different operations in response to different types of touch inputs applied to the key element (e.g., gestures, multi-touch inputs, force inputs with two application locations (e.g., two fingers), and the like). The apparatus may further perform various operations in response to force inputs arising at different locations of the input member, as described herein.Generally, the device 1300 includes a processing system operatively connected to the touch-sensitive element 1310, the strain-sensitive element 1316, and the switching element 1327. The processing system is configured to determine a location of a force input on the input structure 1305 based at least in part on a first signal from the touch sensing element 1310, cause the device 1300 to perform a first process in response to determining, based at least in part on a second signal from the strain sensing element 1316, that the force input satisfies a first force threshold that is less than a second force threshold, and cause the device 1300 to perform a second process different from the first process in response to determining actuation of the switching element 1327 (e.g., at the second force threshold that is greater than the first force threshold). The processing system may also cause the device 1300 to perform a third operation different from the first and second operations in response to sensing (e.g., with the touch sensing element 1310) a touch input on the input structure 1305. The device may also distinguish between different types of touch-based inputs. Thus, the device may perform one operation in response to a tap input and another operation in response to a gesture input.Returning to FIG. 13A, the button 1304 further includes an actuation structure 1328. The actuation structure 1328 is coupled to the sensing element 1308. For example, as described in FIGS. 16A-16C, the actuation structure 1328 may be connected to the posts 1318 of the sensing element 1308. The actuation structure 1328 may be positioned above the switching element 1327, such that the switching element 1327 is between the actuation structure 1328 and the beam structure 1312, such that the actuation structure 1328 applies an actuation force to the switching element 1327, in response to a force input applied to the sensing element 1308.As described herein, the beam structure 1312 is configured to deflect, flex, or otherwise subject to strain when the sensing element 1308 is pressed, and the strain sensing element 1316 (along with associated processors and circuitry) is configured to sense the strain. Because the amount of strain to which the beam structure 1312 is exposed is proportional to or otherwise corresponds to the magnitude of the force applied to the sensing element 1308, the signal of the strain gauge 1316 may correspond to the magnitude of the force. Thus, the device may perform various operations in response to a different amount of force input to the button 1304. In some cases, the beam structure 1312 may define a compliant segment 1330 (see also FIG. 13B ) that may be tuned to have a target stress strain profile. In some cases, the beam structure 1312 defines a recessed region 1314, and the strain gauge 1316 is coupled to the beam structure 1312 in the recessed region 1314. The recessed region 1314 may be configured to cause a particular stress strain behavior of the beam structure 1312. For example, by reducing the thickness of the beam structure 1312 to define the recessed region 1314, the beam structure 1312 can undergo a greater (or more uniform or otherwise desirable) strain response. Further, the recessed region 1314 may have a different stress / strain behavior than other regions of the beam structure 1312 and may be more suitable for strain sensing. For example, the recessed region 1314 may be more heavily loaded or deflected than other regions of the beam structure 1312 (e.g., the region where the switching element 1327 is positioned). For example, a force input to the sensing element 1308 may result in a relatively greater strain in the recessed region (which may improve the ability of the strain sensing element 1316 to accurately sense the force of the input), while resulting in a relatively lower strain or deflection in the area where the switching element 1327 is located (which may improve tactile response and / or set the input force required on the sensing element 1308 to actuate the switching element 1327). The recessed region 1314 may thus at least partially decouple the strain measurement requirements from the switching requirements, as the beam structure 1312 may be tuned to provide different levels of compliance and / or deflection at different locations (e.g., a greater compliance / deflection in response to a particular force in one region to facilitate strain measurement and a lower compliance / deflection in response to a particular force in another region to facilitate switching function).FIG. 13A also illustrates an example configuration of the flexible circuit elements operatively connecting the various systems of the button 1304 to a processing system and / or other circuit. The button 1304 may include a flexible circuit element 1320 operatively coupled to the touch sensing element 1310 and a flexible circuit element 1336 operatively coupled to the strain sensing element 1316 and the switching element 1327. The flexible circuit element 1320 and the flexible circuit element 1336 may be operatively coupled to each other and / or to one or more other flexible circuit elements to ultimately connect the strain sensing element 1316, the touch sensing element 1310, and the switching element 1327 to a processing system. As shown in FIG. 13A, the flexible circuit element 1320 extends into the device at a location where it is otherwise covered by the beam structure 1312. Accordingly, the flexible circuit element 1320 may extend from the hollow post 1318-2 along an inner surface of the housing component 1302. The package component 1302 may form a cavity 1340 on its inside, and the flexible circuit element 1320 may form a loop 1342 that extends into the cavity 1340. The loop 1342 allows the flexible circuit element 1320 to extend through an opening 1344 formed in the beam structure 1312 so that it can mate with the flexible circuit element 1336 (and / or another circuit element or connector) located on the exterior of the beam structure 1312. After this configuration, the flexible circuit element 1320 may be operatively coupled to other components within the device 1300.In some cases, a trim 1338 may be positioned over the flexible circuit elements 1320, 1336 and / or the conductive connectors of the flexible circuit elements. The panel 1338 may be secured at one end to the fastener 1326-2 and at the other end by snap-engaging an opening in the beam structure 1312.FIG. 13B is a partial perspective view of the button 1304 shown separately from the housing 1302 and illustrating a bottom or inside of the beam structure 1312. FIG. 13C is a partial exploded view of the button 1304 and the housing 1302. Referring to FIGS. 13B-13C, the beam structure 1312 defines a compliant segment 1330 that includes the recessed region 1314 and is configured to deflect or otherwise load when a force is input to the sensing element 1308. The strain gauge 1316 and the switching element 1327 are connected to the compliant segment 1330. In FIG. 13C, the operation structure 1328 is not illustrated for ease of illustration.The beam structure 1312 also defines a support segment 1334 that is separated from the compliant segment 1330 by a gap 1332. In other words, the gap 1332 (e.g., a slot extending through the sensing element 1308) may divide the beam structure 1312 into a compliant segment 1330 and a support structure segment 1334. As shown in FIGS. 13C and 14A-14B, the support segment 1336 may receive a stabilizing bar 1346 between the support segment 1336 and the housing. For example, the stabilizing bar 1346 may be positioned in a recess 1348 in the housing, and the beam structure 1312 may be secured to the housing 1302 (e.g., via fasteners 1326 as shown above) such that the stabilizing bar 1346 is received between the housing 1302 and the support segment 1334 of the beam structure 1312.The stabilizing bar 1346 is pivotally connected to both the first and second posts 1318-1, 1318-2. The stabilizing rod 1346 helps the sensing element 1308 not to skew or jam when pressed. For example, off-center forces acting on an elongated sensing element having two posts may cause the sensing element to twist or wobble, which may cause the posts to stick in their holes. The stabilizing bar 1346 helps stabilize the movement of the sensing element 1308 upon force inputs by connecting the posts so that upon force input they always move substantially equidistant regardless of the location of their application.Upon a pressure on the sensing element (e.g., a force input on the input surface), a portion of the input force may be transmitted to the stabilizing bar 1346. In particular, because the support segment 1334 serves to hold the stabilizing bar 1346 in position, the stabilizing bar exerts a force on the support segment 1334 during pressing. By separating the beam structure 1312 into a support segment 1334 and a compliant segment 1330 (e.g., with the slot or gap 1332), the force applied by the stabilizing bar 1346 to the beam structure 1312 can be substantially transferred to the support segment 1334. This may help the force of the stabilizing rod 1346 less impact the strain measurement function of the strain gauge 1316.FIGS. 14-14B show a partial cross-sectional view of the device 1300, as viewed along line 14A- 14A in FIG. 13C, illustrating how the beam structure 1312 may behave during operation of the button. FIG. 14A illustrates the button 1304 in an unactuated state when no force is applied to the button 1308. In this example, no input force is transmitted to the beam structure 1312.FIG. 14B illustrates the button 1304 during actuation when an input force 1402 is applied to the button 1308. In response to the force input 1402, the compliant segment 1330 deflects inward (which may be sensed by the strain gauge 1316 and associated circuitry). The deflection of the compliant segment 1330 may be due to the input force 1402 being applied to the compliant segment 1330 via the actuation structure 1328 that applies a force to the switching element 1327. (While the switching element 1327 is shown in the cross-sections of FIGS. 14A-14B, this is merely illustrative of the operation of the button 1304, and the switching element 1327 may not be present in this particular cross-section.)Due to the gap 1332 between the compliant segment 1330 and the support segment 1334, the forces acting on the various segments of the beam structure 1312 are substantially limited to these segments. For example, the input force applied to the compliant segment 1330 (e.g., via the actuation structure 1328 and the switching element 1327) that results in deflection of the compliant segment 1330 may be substantially isolated from the support segment 1334. In this way, during actuation, the stabilizing rod 1346 remains fixedly received between the beam structure 1312 and the housing 1302. In addition, the force applied to the support segment 1334 by the actuation of the button via the stabilizer bar 1346 is isolated from the compliant segment 1330. In this manner, the force of the stabilizing rod 1346 may be substantially isolated from the compliant segment 1330.As shown in FIGS. 14A-14B, a balancing member 1404 may be positioned between the support segment 1334 and the stabilizing bar 1346. The balancing member 1404 may ensure that the stabilizing rod 1346 remains fixedly received (e.g., in constant contact with) between the support segment 1334 and the housing 1302. The balancing member 1404 may be formed from a polymeric material and configured to resist permanent or elastic deformation such that the force compressing the stabilizing rod 1346 remains substantially constant over time.As mentioned above, the key 1304 may include a touch-sensitive element to provide a touch-sensitive function to the key. The touch scan may be used to determine various aspects of the user inputs on the button 1304. For example, the touch sensor may be used to determine a location on the input surface of the button where input is made. In some cases, the location of the input on the button 1304 may at least partially determine the operation and / or function initiated by the input. For example, an input (e.g., a force input) provided at one location on the tactile element 1308 may result in a first action or operation, and an input provided at another location on the tactile element 1308 may result in a second action or operation (different from the first). Additionally or alternatively, the touch sensing system may sense (and the device may respond to) touch inputs applied to the sensing element 1308 (e.g., inputs that do not include a force component that satisfies a force threshold). The touch sensing system may also sense inputs by gestures (and the device may respond to), such as swipe gestures. To enable these and other touch-sensitive functions, the button 1304 may include a touch-sensitive element 1310 that includes a plurality of touch-sensitive pixels to sense touch inputs, the location of touch inputs, and optionally other parameters of touch inputs, such as the direction of the touch, the speed of the touch, multiple touch points during the touch inputs (and their locations), and the like.FIG. 15 illustrates an exploded view of the input structure 1305 of the button 1304. As shown, the sensing element 1308 has an elongated shape defining a longitudinal axis (which may be parallel to a y-axis or y-direction of the device). The button 1304 further includes a touch-sensitive element 1310 comprising a linear array of touch-sensitive pixels 1504 arranged along the longitudinal axis. Each touch-sensitive pixel 1504 may be configured to sense a touch applied to it. ...

Claims

An electronic device, comprising: a case comprising: a front cover defining a front side of the electronic device; and a housing component connected to the front cover and defining a side of the electronic device; an input structure positioned along the side of the electronic device and configured to receive a force input, the input structure comprising: a sensing element; and a touch sensitive element connected to the sensing element; a beam structure at least partially within the case, the beam structure configured to deflect as a result of the force input; a strain sensing element coupled to the beam structure; a dome switch configured to collapse in response to the force input satisfying a first force threshold; and a processing system operatively coupled to the touch-sensitive element, the strain gauge, and the dome switch and configured to: determine a location of the force input on the input structure based at least in part on a first signal of the touch-sensitive element; cause the electronic device to perform a first operation when the force input is detected based on a second signal of the strain gauge element to meet a second force threshold that is less than the first force threshold; and cause the electronic device to perform a second operation different than the first operation in response to detecting the collapse of the dome switch.The electronic device of claim 1, wherein: the electronic device further comprises a haptic actuation system; the processing system is configured to cause the haptic actuation system to generate a first haptic output in response to detecting that the force input satisfies the second force threshold; and the dome switch generates a second haptic output when collapsed in response to the force input satisfying the first force threshold.The electronic device of claim 1, wherein: the electronic device further includes: a camera; and a display configured to display graphical user interfaces; the second operation includes causing the display to transition to a graphical user interface associated with an image capture function; and the processing system is further configured to capture an image in response to detecting the collapse of the dome switch.The electronic device of claim 1, wherein the touch-sensitive element comprises a linear array of touch-sensitive pixels.The electronic device of claim 1, wherein the processing system is further configured to: detect gesture input applied to the input structure based at least in part on a third signal of the touch-sensitive element; and cause the electronic device to perform a third operation different from the first and second operations in response to detecting the gesture input.The electronic device of claim 5, wherein the third operation comprises a zoom operation for an image capture function.The electronic device of claim 6, wherein: the gesture input is a first gesture input corresponding to a swiping motion in a first direction; the zooming operation comprises a zoom-in operation; and the processing system is further configured to: detect a second gesture input corresponding to a swiping motion in a second direction opposite the first direction; and perform a shrinking operation in response to detecting the second gesture input.A portable electronic device, comprising: a touch screen display; a battery; a shell enclosing the touch screen display and the battery, the shell comprising: a front cover positioned over the touch screen display and defining a front outer surface of the shell; and a housing component connected to the front cover and defining an opening along an outer surface of the shell; and an input key system comprising: a beam structure at least partially located within the shell and forming a compliant segment; a strain gauge connected to the compliant segment; a switching element coupled to the beam structure; a sensing element at least partially positioned in the opening and configured to apply a force to the switching element as a result of a force input applied to the sensing element; and a touch sensing element connected to the touch element; and a processing system configured to: cause the portable electronic device to perform a first operation when the force input satisfies a force threshold based at least in part on a first signal of the strain sensing element; cause the portable electronic device to perform a second operation different from the first operation in response to detecting a touch input applied to the input key system based at least in part on a second signal from the touch sensing element; and cause the portable electronic device to perform a third operation different from the first and second operations in response to detecting the operation of the switching element.The electronic device of claim 8, wherein: the sensing element defines: a chassis portion; and a hollow post extending into a hole defined by the housing component; and the input key system further comprises a flexible circuit element coupled to the touch-sensitive element and extending through the hollow post, the flexible circuit element operatively connecting the touch-sensitive element to the processing system.The portable electronic device of claim 9, further comprising a potting material at least partially filling the hollow post and encapsulating at least a portion of the flexible circuit element.The electronic device of claim 8, wherein: the sensing element has an elongated shape defining a longitudinal axis; and the touch-sensitive element comprises a linear array of touch-sensitive pixels arranged along the longitudinal axis.The portable electronic device of claim 8, wherein the touch input corresponds to a swiping gesture along an input surface of the input key system, the swiping gesture having a swiping direction.The electronic device of claim 12, wherein: the second operation corresponds to a zooming operation of an image pickup function; and a direction of the zooming operation corresponds to the wiping direction.The electronic device of claim 8, wherein: the wearable electronic device further comprises a haptic actuation system; and the processing system is configured to: cause the haptic actuation system to generate a first haptic output when it is detected that the force input satisfies the force threshold; and cause the haptic actuation system to generate a second haptic output in response to a notification event.A mobile phone, comprising: a housing component; a front cover connected to the housing component; a display positioned below the front cover; an input key system positioned along a side of the housing component and responsive to a first force input satisfying a first force threshold, a second force input satisfying a second force threshold different from the first force threshold, and a touch input, the input key system comprising: a touch element; a touch sensitive element connected to the touch element; a beam structure configured to be deflected by the touch element in response to the first and second force inputs; a strain gauge coupled to the beam structure; A switching element configured to be actuated in response to the second force input satisfying the second force threshold; and a processing system operatively coupled to the touch sensing element, the strain sensing element, and the switching element and configured to: cause the mobile phone to perform a first operation in response to detecting the touch input with the touch sensing element; cause the mobile phone to perform a second operation in response to determining with the strain sensing element that the second force input satisfies the first force threshold; and cause the mobile phone to perform a third operation in response to detecting actuation of the switching element.The mobile phone of claim 15, wherein: the input key system further comprises an actuation structure coupled to the key; the switch element is coupled to the beam structure and is positioned between the beam structure and the actuation structure; and the actuation structure applies an actuation force to the switch element in response to the second force input.The mobile phone of claim 15, wherein: the beam structure defines: a compliant segment; and a support segment separated from the compliant segment by a gap; the switching element is connected to the compliant segment; and the strain gauge is connected to the compliant segment.The mobile phone of claim 17, wherein: the sensing element defines: a chassis portion; a first post extending from the chassis portion through a first hole formed through the housing component; and a second post extending from the chassis portion through a second hole formed through the housing component; and the input key system further comprises a stabilizing bar connected to the first post and the second post and received between the support segment of the beam structure and the housing component.The mobile phone of claim 18, wherein: the first post is a hollow post; and the input key system further comprises a circuit element conductively connected to the touch-sensitive element and extending through the hollow post, the circuit element operatively connecting the touch-sensitive element to the processing system.The mobile phone of claim 19, wherein the input key system further comprises: a cover connected to the key element and positioned over the touch sensitive element; and a potting material at least partially encapsulating the touch sensitive element and the element of the circuit and at least partially filling the hollow post.

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