PATENT DOCUMENT

Publication Number: US-10871828-B2
Application Number: US-201815939123-A
Country: US
Kind Code: B2

Title: Device having integrated interface system

Abstract:
A portable computer includes a display portion comprising a display, a base portion pivotally coupled to the display portion and including a glass top case. The glass top case defines an exterior surface and a keyboard opening through the glass top case from the exterior surface to an interior surface. The portable computer further includes a keyboard positioned at least partially within the keyboard opening and comprising a substrate, a key configured to move relative to the substrate, and a fabric cover disposed over the key and defining a user interface surface of the key.

Claims:
What is claimed is: 
     
       1. A portable computer comprising:
 a display portion comprising a display; 
 a base portion pivotally coupled to the display portion and comprising a glass top case defining: 
 
       an exterior surface; and
 a keyboard opening through the glass top case from the exterior surface to an interior surface; and 
 a keyboard positioned at least partially within the keyboard opening and comprising:
 a substrate; 
 a key configured to move relative to the substrate and comprising:
 a keycap support; and 
 a glass keycap bonded to the keycap support; and 
 
 a flexible fabric cover covering a gap between the key and an adjacent key and having a portion positioned in a recess defined between the keycap support and the glass keycap. 
 
 
     
     
       2. The portable computer of  claim 1 , wherein:
 the key is a first key; 
 the keyboard further comprises:
 a key web defining a first key opening and a second key opening, and a plurality of additional key openings; and 
 a second key; 
 
 the first key is positioned at least partially in the first key opening; 
 the second key is positioned at least partially in the second key opening; 
 the keyboard comprises a plurality of additional keys, each positioned at least partially in a corresponding key opening; 
 the flexible fabric cover is disposed over the key web; and 
 the flexible fabric cover defines: 
 a keyboard region; and 
 an outer region framing the keyboard region. 
 
     
     
       3. The portable computer of  claim 2 , wherein the outer region is captured between the glass top case and an underlying component. 
     
     
       4. The portable computer of  claim 1 , wherein the glass top case further defines a trackpad region. 
     
     
       5. The portable computer of  claim 4 , wherein:
 the keyboard opening is a rectangular opening;
 the trackpad region comprises:
 a first portion of the glass top case along a first side of the keyboard opening; 
 a second portion of the glass top case along a second side of the keyboard opening; and 
 a third portion of the glass top case along a third side of the keyboard opening; and 
 
 the portable computer further comprises a touch sensing system configured to detect a touch input applied to any of the first portion, the second portion, and the third portion of the glass top case. 
 
 
     
     
       6. The portable computer of  claim 5 , further comprising a force sensing system configured to determine a force associated with the touch input. 
     
     
       7. The portable computer of  claim 5 , wherein the glass top case defines:
 a top of the base portion; and 
 at least three sidewalls of the base portion. 
 
     
     
       8. The portable computer of  claim 1 , wherein:
 the glass keycap defines a user interface surface of the key; and 
 the portable computer further comprises a touch sensing system below the glass top case and configured to detect touch inputs applied to the user interface surface of the key. 
 
     
     
       9. The portable computer of  claim 1 , wherein further comprising a flexible polymer membrane extending over the gap between the key and the adjacent key and positioned below the flexible fabric cover and having the portion positioned in the recess defined between the keycap support and the glass keycap. 
     
     
       10. A notebook computer, comprising:
 a display portion comprising: 
 a display housing; and 
 a display within the display housing; 
 a base portion coupled to the display portion and comprising: 
 a bottom case; and 
 a glass top case coupled to the bottom case and defining an opening extending through the glass top case; 
 a touch sensing system below the glass top case and configured to detect a touch input applied to any location on the glass top case; and 
 a keyboard positioned at least partially in the opening and comprising: 
 a first key mechanism of a plurality of key mechanisms each comprising: 
 a keycap support; and 
 a glass keycap attached to the keycap support; and 
 a flexible fabric cover extending across a gap between the first key mechanism and a second key mechanism of the plurality of key mechanisms and configured to deflect in response to actuation of the first key mechanism, the flexible fabric cover having an edge portion defining a hole through which at least a portion of the first key mechanism extends, the edge portion disposed in a recess defined between the keycap support and the glass keycap. 
 
     
     
       11. The notebook computer of  claim 10 , wherein the glass top case defines a surface that extends continuously around the opening. 
     
     
       12. The notebook computer of  claim 11 , further comprising an additional display positioned under at least a portion of the glass top case. 
     
     
       13. The notebook computer of  claim 12 , wherein the additional display is configured to display affordances that are selectable by a user touching the glass top case. 
     
     
       14. A device, comprising:
 a display portion comprising a display; 
 a base portion flexibly coupled to the display portion and comprising: 
 a keyboard comprising: 
 a plurality of keys, each respective key of the plurality of keys comprising a respective keycap support and a respective glass keycap; and 
 a flexible sheet covering a gap between adjacent keys of the plurality of keys and having an edge portion that defines a hole through the flexible sheet and is captive in a recess between a keycap and a keycap support of a given key of the plurality of keys; and 
 a continuous glass frame extending around a periphery of the keyboard and defining: 
 a first touch-sensitive input region adjacent a first side of the keyboard; and 
 a second touch-sensitive input region adjacent a second side of the keyboard; and 
 a touch sensing system configured to determine a location of touch inputs applied to the first and second touch-sensitive input regions. 
 
     
     
       15. The device of  claim 14 , wherein:
 the keyboard defines a first portion of a top of the base portion; and 
 the continuous glass frame defines all remaining portions of the top of the base portion. 
 
     
     
       16. The device of  claim 15 , wherein:
 the display is a first display; and 
 the device further includes a second display configured to display an affordance on the first touch-sensitive input region. 
 
     
     
       17. The device of  claim 15 , wherein the keyboard further comprises a flexible membrane positioned below the flexible sheet and covering the gap between the adjacent keys. 
     
     
       18. The device of  claim 17 , wherein the flexible sheet and the flexible membrane are formed of different materials. 
     
     
       19. The device of  claim 17 , wherein an edge of the flexible membrane is captive in the recess between the keycap and the keycap support of the given key.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a nonprovisional patent application of and claims the benefit of U.S. Provisional Patent Application No. 62/478,537, filed Mar. 29, 2017, and titled “Device Having Integrated Interface System,” the disclosure of which is hereby incorporated by reference herein in its entirety. 
    
    
     FIELD 
     The described embodiments relate generally to electronic devices, and more particularly to an electronic device having a transparent, dielectric input surface integrated with the enclosure of the device. 
     BACKGROUND 
     Many electronic devices include one or more input devices such as keyboards, trackpads, mice, or touchscreens to enable a user to interact with the device. In some traditional electronic devices, the inclusion of one or more of the input devices may require the formation of a hole, opening, or seam through which liquid or other foreign matter may enter the device enclosure. Additionally, the enclosure of some traditional electronic devices may be formed from materials that are easily scratched or that provide an inferior tactile feel or visual appearance. 
     The embodiments described herein are generally directed to electronic devices having an enclosure formed at least partially from a transparent, dielectric material such as plastic, glass, or a ceramic material. The transparent dielectric material may form a continuous or seamless input surface that may improve the look and feel of the device without having the drawbacks of some traditional device constructions. 
     SUMMARY 
     A portable computer may include a display portion including a display and a base portion pivotally coupled to the display portion. The base portion may include a bottom case and a top case that is formed from a dielectric material and coupled to the bottom case. The top case may include a top member defining a top surface of the base portion and a sidewall integrally formed with the top member and defining a side surface of the base portion. The portable computer may further include a sensing system including a first sensing system configured to determine a location of a touch input applied to the top surface of the base portion, and a second sensing system configured to determine a force of the touch input. The top case may be formed from a transparent material. 
     The top case may be formed from a single glass member. The sidewall may be a first sidewall, the side surface may be a first side surface, and the top case may further include a second sidewall integrally formed with the first sidewall and the top member and defining a second side surface of the base portion, and a third sidewall integrally formed with the first sidewall, the second sidewall, and the top member and defining a third side surface of the base portion. 
     The first sensing system may be positioned below the top member and may extend over an entire area of the top member, and the second sensing system may be positioned below the top member and may extend over the entire area of the top member. The top member may define an opening, and the portable computer may further include a keyboard positioned in the opening. 
     The display may be a first display, and the portable computer may further include a second display within the base portion and viewable through the top case. The second display may be configured to display an image of a keyboard in a keyboard region of the top case. The image of the keyboard may include an image of a key, and the second sensing system may be configured to register a key input in response to detecting an input applied to the key and having a force exceeding a force threshold. 
     A device may include a display portion that includes a display housing, and a display within the display housing. The device may further include a base portion coupled to the display portion and including a bottom case and a glass top case coupled to the bottom case and defining a top exterior surface of the base portion. The device may further include a sensing system configured to determine a location of a touch input applied to any location on the top exterior surface of the base portion and to determine a force of the touch input applied to any location on the top exterior surface of the base portion. The sensing system may include a touch sensing system configured to determine the location of the touch input and a force sensing system configured to determine the force of the touch input and to determine the location of the touch input. The top case may be configured to locally deform in response to the touch input, and the device may be configured to register an input at the location of the touch input if the determined force exceeds a threshold force. 
     The device may further include a haptic device configured to produce a haptic output at the top case in response to registering the input at the location of the touch input. The haptic output may produce a localized haptic output such that a magnitude of the haptic output at the location is greater than the magnitude of the haptic output at a different location adjacent to the location. The haptic device may include a piezoelectric material coupled to the top case. 
     The top case may define an opening, and the device may further include a keyboard positioned at least partially in the opening. The bottom case may define a bottom member, a first sidewall integrally formed with the bottom member, a second sidewall integrally formed with the bottom member, and a third sidewall integrally formed with the bottom member. The top case may be attached to the bottom case via the first, second, and third sidewalls. 
     A notebook computer may include a display portion that includes a display, and a base portion flexibly coupled to the display portion and including a bottom case and a glass top case coupled to the bottom case and defining substantially an entire top surface of the base portion. The notebook computer may further include a touch sensing system configured to determine a location of a touch event applied to the top case, and a force sensing system configured to cause the notebook computer to register an input in response to a force associated with the touch event exceeding a threshold. 
     The glass top case may define a keyboard region and a trackpad region, and the notebook computer may be configured to register the input as a key input if the location of the touch event is within the keyboard region. The force sensing system may be configured to determine if a palm of a user is resting on the trackpad region. In response to the force sensing system determining that the palm of the user is not resting on the trackpad region, the notebook computer may set the threshold to a first threshold, and in response to the force sensing system determining that the palm of the user is resting on the trackpad region, the notebook computer may set the threshold to a second threshold different from the first threshold. The notebook computer may be configured to register the input as a trackpad input if the location of the touch event is within the trackpad region. The notebook computer may be configured to take a first action in response to registering the input as the key input and to take a second action different from the first action in response to registering the input as a trackpad input. 
     The notebook computer may further include a haptic device configured to produce a haptic output at the glass top case in response to registering the input as the trackpad input or the key input. 
     A device may include a display portion that includes a display housing, a display within the display housing, a base portion flexibly coupled to the display portion and including a glass member defining a keyboard region configured to receive user input, a first haptic actuator configured to produce a first haptic output at a first area of the keyboard region, and a second haptic actuator configured to produce a second haptic output at a second area of the keyboard region that is different from the first area. The device may further include a keyboard region having keys. The first area may correspond to a first key of the keyboard region, and the second area may correspond to a second key of the keyboard region. 
     The device may further include a touch sensing system configured to determine whether a touch input is applied to the first key, and the first haptic actuator may produce the first haptic output in response to determining that the touch input is applied to the first key. 
     The device may further include a force sensing system configured to determine a force associated with a touch input applied to the first key, and the first haptic actuator may produce the first haptic output in response to determining that the force exceeds a force threshold. The force threshold may correspond to a force associated with a typing input on the first key. 
     The glass member may further define a trackpad region, and the device may further include a third haptic actuator configured to produce a third haptic output at any location in the trackpad region. The keyboard region may correspond to a planar surface of the glass member, the first and second haptic actuators may be configured to impart an out-of-plane force to the glass member, and the third haptic actuator may be configured to impart an in-plane force to the glass member. 
     A notebook computer may include a display portion that includes a display and a base portion pivotally coupled to the display portion and including a bottom case and a glass top case coupled to the bottom case. The glass top case may define a keyboard region and a trackpad region adjacent the keyboard region. The notebook computer may further include a force sensing system configured to detect inputs applied to the glass top case within the keyboard region and the trackpad region, a first haptic actuator configured to produce a first haptic output in response to the force sensing system detecting a first input within the keyboard region, and a second haptic actuator configured to produce a second haptic output different from the first haptic output in response to the force sensing system detecting a second input within the trackpad region. 
     The first haptic output may include a localized deflection of the glass top case within the keyboard region, and the second haptic output may include a force applied to the glass top case in a direction that is in-plane with a surface of the trackpad region. 
     The first haptic actuator may include a piezoelectric actuator, and the second haptic actuator may include a mass and an electromagnetic actuator configured to move the mass to produce the second haptic output. 
     The glass top case may define a planar surface, and the keyboard region and the trackpad region may be defined on the planar surface. The glass top case may define all of a top surface of the base portion. 
     The keyboard region may include a plurality of keys defined by a mask layer below the glass top case. 
     The display may be a first display, the notebook computer may further include a second display in the base portion and visible through the glass top case, and the second display may display images of keys within the keyboard region. The second display may display a border around at least a portion of the trackpad region. 
     A portable computer may include a display housing, a display positioned at least partially in the display housing, and a base portion coupled to and configured to rotate relative to the display housing. The base portion may include a metal member defining a bottom surface of the base portion and a glass member defining a top surface of the base portion. The portable computer may also include a first haptic actuator configured to produce a first type of haptic output in response to a first type of input detected on the glass member, and a second haptic actuator configured to produce a second type of haptic output, different from the first type of haptic output, in response to a second type of input detected on the glass member. The glass member may define a first touch sensitive region and a second touch sensitive region adjacent the first touch sensitive region. The first type of input may correspond to an input detected within the first touch sensitive region, and the second type of input may correspond to an input detected within the second touch sensitive region. The top surface may be an entire top surface of the base portion. 
     The first haptic actuator may be configured to locally deform the glass member, and the second haptic actuator may be configured to move at least a portion of the glass member along a direction that is parallel to a plane defined by the top surface of the base portion. The first haptic actuator may be a piezoelectric actuator that is configured to locally deform a region of the glass member corresponding to a single key. 
     A portable computer may include a display portion that includes a display and a base portion pivotally coupled to the display portion and including a glass top case defining an exterior surface and a keyboard opening through the glass top case from the exterior surface to an interior surface. The portable computer may further include a keyboard positioned at least partially within the keyboard opening and including a substrate, a key configured to move relative to the substrate, and a fabric cover disposed over the key and defining a user interface surface of the key. The portable computer may further include a touch sensing system below the glass top case and configured to detect touch inputs applied to the user interface surface of the key. The portable computer may further include a force sensing system configured to determine a force associated with the touch input. 
     The keyboard may further include a key web defining a key opening and a plurality of additional key openings, and the key may be positioned at least partially in the key opening. The keyboard may further include a plurality of additional keys, each positioned at least partially in a corresponding key opening. The fabric cover may be disposed over the key web and the plurality of additional keys, and the fabric cover may define a keyboard region covering the key and the plurality of additional keys, and an outer region framing the keyboard region. 
     The outer region may be captured between the glass top case and an underlying component. At least a portion of the fabric cover is adhered to the key. 
     The glass top case may further define a trackpad region. The keyboard opening may be a rectangular opening, and the trackpad region may include a first portion of the glass top case along a first side of the keyboard opening, a second portion of the glass top case along a second side of the keyboard opening, and a third portion of the glass top case along a third side of the keyboard opening. The portable computer may further include a touch sensing system configured to detect a touch input applied to any of the first portion, the second portion, and the third portion of the glass top case. The glass top case may define a top of the base portion, and at least three sidewalls of the base portion. 
     A notebook computer may include a display portion that includes a display housing and a display within the display housing. The notebook computer may further include a base portion coupled to the display portion and including a bottom case and a glass top case coupled to the bottom case and defining an opening extending through the glass top case. The notebook computer may further include a touch sensing system below the glass top case and configured to detect a touch input applied to any location on the glass top case, and a keyboard positioned at least partially in the opening. The keyboard may include a plurality of key mechanisms and a fabric cover extending across a gap between two of the key mechanisms. The glass top case may define a surface that extends continuously around the opening. 
     The plurality of key mechanisms may each include a keycap support and a keycap, and at least a portion of the fabric cover may be disposed between the keycap support and the keycap. The portion of the fabric cover disposed between the keycap support and the keycap may be adhered to the keycap support, and the keycap may be adhered to the fabric cover above the keycap support. 
     The notebook computer may further include an additional display positioned under at least a portion of the glass top case. The additional display may be configured to display affordances that are selectable by a user touching the glass top case. 
     The notebook computer may further include a force sensing system configured to determine an amount of force associated with the touch input detected on the glass top case. 
     A device may include a display portion that includes a display, and a base portion flexibly coupled to the display portion and including a keyboard including keys and having a flexible sheet covering a gap between adjacent keys. The device may further include a continuous glass frame extending around a periphery of the keyboard and defining a first touch-sensitive input region adjacent a first side of the keyboard, and a second touch-sensitive input region adjacent a second side of the keyboard. The device may further include a touch sensing system configured to determine a location of touch inputs applied to the first and second touch-sensitive input regions. 
     The keyboard may define a first portion of a top of the base portion, and the continuous glass frame defines all remaining portions of the top of the base portion. At least a portion of the flexible sheet may be captive between keycap supports and respective keycaps that are coupled to respective keycap supports. A key of the keys may include an input surface defined exclusively by the flexible sheet. 
     The display may be a first display, and the device may further include a second display configured to display an affordance on the first touch-sensitive input region. The affordance may be displayed based on content that is displayed on the first display. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which: 
         FIG. 1A  depicts a simplified example of a computing device. 
         FIG. 1B  depicts a simplified function block diagram of the computing device of  FIG. 1A . 
         FIG. 2A  depicts an exploded view of the computing device of  FIG. 1A . 
         FIGS. 2B-2F  depict partial cross-sectional views of a portion of the computing device of  FIG. 1A , viewed along section A-A in  FIG. 1A . 
         FIG. 3A  depicts an exploded view of a base portion of the computing device of  FIG. 1A . 
         FIG. 3B  depicts a partial cross-sectional view of the base portion of the computing device of  FIG. 1A , viewed along section B-B in  FIG. 1A . 
         FIGS. 4A-5D  depict partial cross-sectional views of the base portion of the computing device of  FIG. 1A , viewed along section B-B in  FIG. 1A . 
         FIGS. 6A-6H and 6J  depict partial cross-sectional views of a display portion of the computing device of  FIG. 1A , viewed along section C-C in  FIG. 1A . 
         FIGS. 7A-7B  depict partial cross-sectional views of the computing device of  FIG. 1A , viewed along sections B-B and C-C in  FIG. 1A . 
         FIGS. 8A-8B  depict exploded views of example top cases of a computing device. 
         FIG. 9A  depicts an exploded view of another example top case for a computing device. 
         FIG. 9B  depicts a partial cross-sectional view of the top case of  FIG. 9A , viewed along section D-D in  FIG. 9A . 
         FIG. 10  depicts another example top case for a computing device. 
         FIG. 11A  depicts an exploded view of an illuminated base portion for a computing device. 
         FIG. 11B  depicts a partial cross-sectional view of the base portion of  FIG. 11A , viewed along section E-E in  FIG. 11A . 
         FIGS. 11C-11E  depict example illuminated base portions in accordance with  FIGS. 11A-11B . 
         FIGS. 11F-11G  depict an example illuminated computing device. 
         FIG. 11H  depicts an example illuminated base portion in accordance with  FIGS. 11F-11G . 
         FIG. 12A  depicts an example computing device having a flat top case. 
         FIG. 12B  depicts an exploded view of a base portion of the example computing device of  FIG. 12A . 
         FIG. 13A  depicts an example computing device having a contoured top case. 
         FIG. 13B  depicts an exploded view of an example base portion of the computing device of  FIG. 13A . 
         FIG. 13C  depicts an exploded view of another example base portion of the computing device of  FIG. 13A . 
         FIG. 13D  depicts an exploded view of another example base portion of the computing device of  FIG. 13A . 
         FIG. 13E  depicts an exploded view of another example base portion of the computing device of  FIG. 13A . 
         FIGS. 13F-13H and 13J-13K  depict partial cross-sectional views of example arrangements of components in the base portion of  FIG. 13E . 
         FIG. 13L  depicts an exploded view of another example base portion of the computing device of  FIG. 13A . 
         FIGS. 13M-13O  depict portions of example base plates of the base portion of  FIG. 13L . 
         FIG. 14A  depicts another example computing device having a contoured top case. 
         FIG. 14B  depicts an exploded view of a base portion of the example computing device of  FIG. 14A . 
         FIG. 15A  depicts another example computing device having a contoured top case. 
         FIG. 15B  depicts an exploded view of a base portion of the example computing device of  FIG. 15A . 
         FIGS. 16A-16C  depict an example computing device having a virtual keyboard. 
         FIGS. 16D-16G  depict the example computing device of  FIGS. 16A-16C  in conjunction with a keyboard accessory. 
         FIGS. 17A-17B  depict exploded views of example base portions of the computing device of  FIGS. 16A-16C . 
         FIGS. 18A-18B  depict partial exploded views of example base portions of a computing device having a touch-sensitive input surface. 
         FIGS. 18C-18D  depict portions of the touch sensor of  FIG. 18B   
         FIGS. 18E-18F  depict other examples of top cases of a computing device having a touch-sensitive input surface. 
         FIG. 19A  depicts an example top case for a computing device. 
         FIGS. 19B-19D  depict partial cross-sectional views of the top case of  FIG. 19A , viewed along section F-F in  FIG. 19A . 
         FIG. 20A  depicts another example top case for a computing device. 
         FIGS. 20B-20C  depict partial cross-sectional views of the top case of  FIG. 20A , viewed along section G-G in  FIG. 20A . 
         FIGS. 21A-21D  depict schematic views of an input surface having an integrated force sensor or force-sensing capabilities. 
         FIGS. 22A-22H and 22J-22M  depict example force sensors. 
         FIG. 23  depicts an example top case having an example force sensor positioned around a perimeter of the top case. 
         FIGS. 24A and 24B  depict cross-sectional views of the top case and force sensor of  FIG. 23 . 
         FIG. 25  depicts an exploded view of a top case having an example two-layer force sensor. 
         FIGS. 26A-26B  depict an example device having a haptic actuator. 
         FIGS. 27A-27D  depict example global haptic outputs. 
         FIGS. 28A-28B  depict example localized haptic outputs. 
         FIGS. 29A-29H and 29J-29K  depict example haptic devices. 
         FIGS. 30A-30B  depict example arrangements of different haptic devices over a contact surface of an example top case. 
         FIG. 30C  depicts an example joining technique for a top case and a bottom case. 
         FIGS. 31A-31B  depict an example computing device being used for text and/or touch input. 
         FIG. 32A  depicts an example computing device with a finger sensing system. 
         FIGS. 32B-32E  depict partial cross-sectional views of the computing device of  FIG. 32A , viewed along section I-I in  FIG. 32A . 
         FIGS. 33A-33B  depict schematic views of an input key. 
         FIGS. 34A-34B  depict partial cross-sectional views of an example input key, viewed along section J-J in  FIG. 13A . 
         FIGS. 35A-35B  depict partial cross-sectional views of another example input key, viewed along section J-J in  FIG. 13A . 
         FIGS. 36A-36B  depict partial cross-sectional views of another example input key, viewed along section J-J in  FIG. 13A . 
         FIG. 37A-37B  depict partial cross-sectional views of another example input key, viewed along section J-J in  FIG. 13A . 
         FIG. 38  depicts a partial cross-sectional view of an example computing device with an illuminated keyboard, viewed along section J-J in  FIG. 13A . 
         FIG. 39A  depicts a cross-sectional view of an example keycap for an illuminated keyboard. 
         FIG. 39B  depicts a cross-sectional view of another example keycap for an illuminated keyboard. 
         FIG. 40A  depicts a partial cross-sectional view of another example computing device with an illuminated keyboard, viewed along section J-J in  FIG. 13A . 
         FIG. 40B  depicts a top view of the top case of  FIG. 40A . 
         FIG. 41A  depicts a partial cross-sectional view of another example computing device with an illuminated keyboard, viewed along section J-J in  FIG. 13A . 
         FIG. 41B  depicts a partial cross-sectional view of another example computing device with an illuminated keyboard, viewed along section J-J in  FIG. 13A . 
         FIG. 41C  depicts a partial cross-sectional view of another example computing device with an illuminated keyboard, viewed along section J-J in  FIG. 13A . 
         FIG. 42A-42B  depict partial cross-sectional views of another example computing device with an illuminated keyboard, viewed along section J-J in  FIG. 13A . 
         FIG. 42C  depicts a partial cross-sectional view of another example computing device with an illuminated keyboard, viewed along section J-J in  FIG. 13A . 
         FIGS. 43A-43C  depict cross-sectional views of an example key of a computing device. 
         FIGS. 44A-44D  depict cross-sectional views of another example key of a computing device. 
         FIG. 45A  depicts a cross-sectional view of another example key of a computing device. 
         FIG. 45B  depicts a cross-sectional view of another example key of a computing device. 
         FIG. 46  depicts a cross-sectional view of another example key of a computing device. 
         FIGS. 47A-47B  depict side views of example keycaps. 
         FIGS. 48A-48F  depict example computing devices receiving various touch inputs. 
         FIGS. 49A-49B  depict example computing devices interfacing with external objects. 
         FIG. 50  depicts a schematic diagram of an electronic device. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the described embodiments as defined by the appended claims. 
     The embodiments described herein are generally directed to a portable electronic device (e.g., portable computer, notebook computer, laptop computer, etc.) having an upper portion of the enclosure formed from a dielectric material, such as plastic, ceramic, glass, composites, or combinations thereof. The component formed from the dielectric material may define part of an internal volume of the enclosure for housing various components of the portable device, and may also define an input surface of an integrated interface system that allows a wide variety of touch and keyboard inputs. In particular, the integrated interface system may serve as a trackpad, a keyboard, or may provide both trackpad and keyboard functionalities, and the dielectric component may define all or part of the keyboard and trackpad regions. 
     In some embodiments described herein, the integrated interface system may be integrated with multiple sensors, including touch and force sensors, that can detect various types of inputs applied to various regions of an input surface. In some instances, the touch and/or force sensors are formed into a unified structure that is configured to detect touch inputs applied to a non-keyboard region as well as key inputs applied to a keyboard region (which may include mechanical and/or virtual keys). In accordance with embodiments described herein, the integrated interface system may also be used to detect gestures and multi-touch inputs applied to keycaps of a mechanical keyboard, allowing the keycaps and keyboard region to function as a trackpad. 
     The integrated interface system may also provide various types of output functionality, including visual outputs, haptic outputs, and the like. For example, images of affordances (e.g., keys, keyboards, buttons, sliders, dials, etc.) may be displayed on the top case (e.g., with a display device) to indicate where a touch or force input may be provided. As another example, the top case of the integrated interface system may be configured to move or oscillate to provide tactile or haptic outputs in response to the detection of touch or force inputs. The integrated interface system may thus provide comprehensive input and output functionality via an integrated input/output surface. 
     As noted above, a component that defines the input surface of the integrated interface system may be formed from a continuous and/or seamless sheet of a dielectric material, such as glass, plastic, or ceramic (e.g., it may be a single glass member). The sheet may have properties that enable the diverse input and output functions described herein. For example, the sheet may be strong and may have a high resistance to scratching, and may provide a surface finish having a superior appearance and/or tactile feel as compared with other materials or components. The sheet may also be a dielectric and/or substantially nonconductive, allowing touch and force inputs to be detected through the sheet, and allowing electromagnetic waves and/or fields (e.g., radio frequency signals, inductive power, inductive signals, and other wireless communications or electromagnetic energy transfer) to pass through without substantial attenuation. The sheet may be continuous or seamless, which may help prevent the ingress of liquid or other foreign debris. The sheet may also be light transmissive to allow images or light to be visible therethrough. As used herein, light transmissive may be used to refer to something that is transparent or translucent, or otherwise allows light to propagate therethrough. In some cases, transparent materials or components may introduce some diffusion, lensing effects, distortions, or the like (e.g., due to surface textures) while still allowing objects or images to be seen through the materials or components, and such deviations are understood to be within the scope of the meaning of transparent. Also, materials that are transparent may be coated, painted, or otherwise treated to produce a non-transparent (e.g., opaque) component; in such cases the material may still be referred to as transparent, even though the material may be part of an opaque component. Translucent components may be formed by producing a textured or frosted surface on an otherwise transparent material (e.g., clear glass). Translucent materials may also be used, such as translucent polymers, translucent ceramics, or the like. 
       FIG. 1A  depicts a computing device  100  (or simply “device  100 ”) that may include an integrated interface system, as described above. In particular, a base portion  104  of the device  100  may include a top case  112  that defines a portion of an enclosure and also forms or is part of the integrated interface system described herein. 
     The device  100  may be or may resemble a portable computer, also known as a notebook or laptop computer, that has a display portion  102  and a base portion  104  flexibly or pivotally coupled to the display portion  102  (e.g., so that the display portion  102  is able to rotate, pivot, flex, articular, or otherwise move relative to the base portion  104 ). The display portion  102  includes a display, also referred to as a primary display, that provides a primary means of conveying visual information to the user, such as by displaying graphical user interfaces. The base portion  104  is configured to receive various types of user inputs, such as keyboard inputs (e.g., typing), touch inputs (e.g., gestures, multi-touch inputs, swipes, taps, etc.), and the like. The base portion  104  may also provide outputs for conveying information to a user, such as with indicator lights, haptic output devices, displays mounted in the base portion  104 , or the like. In some cases, providing various types of input and output via the base portion  104  is facilitated or enabled by using a continuous top surface on the base portion  104 , as described herein. 
     The display portion  102  and the base portion  104  may be coupled to one another such that they can be positioned in an open position and a closed position. In the open position, a user may be able to provide inputs to the device  100  via the base portion  104  while simultaneously viewing information on the display portion  102 . In the closed position, the display portion  102  and the base portion  104  are collapsed against one another. More particularly, the display portion  102  and the base portion  104  may be hinged together (e.g., via a pivot mechanism or hinge  103 ) to form a clamshell device that can be moved between an open and a closed configuration. 
     Information and/or data may be transferred between the display portion  102  and the base portion  104 . For example, display data, such as data or signals that cause the display portion  102  to display images, user interfaces, application data, or the like, may be sent to the display portion  102  from the base portion  104 . Similarly, input data may be sent from the display portion  102  to the base portion  104 . Input data may include data relating to touch inputs applied to a touchscreen within the display portion  102 , sensor data (e.g., from sensors in the display portion  102 , such as light sensors, accelerometers, etc.), camera data (e.g., from a camera in the display portion  102 ), or the like. The device  100  may include any appropriate communication system for transferring data between the display portion  102  and the base portion  104 , such as wired or wireless communications systems. Wireless communications systems may include a first transmitter/receiver in the display portion  102 , and a second transmitter/receiver in the base portion  104  that communicates with the first transmitter/receiver. The first and second transmitter/receiver may communicate in any suitable way and use any suitable wireless frequency or frequencies (e.g., 2.4 GHz, 60 GHz), communication protocol(s), etc. The first and second transmitter/receiver may also communicate via an optical communication link. 
     Power may also be transferred between the base portion  104  and the display portion  102 . For example, either or both of the base portion  104  and the display portion  102  may include batteries or other power sources. Power can be sent from one portion to another portion as needed based on the power demands and power supplies of each portion. For example, the base portion  104  and the display portion  102  may include batteries as well as components that require power. Power may be distributed from any battery to any circuit or component that requires power, regardless of the location of the battery or the circuit or component. Power may be transferred between the base portion  104  and the display portion  102  using any suitable components and techniques. For example, a wired or physical power connection may couple the display portion  102  to the base portion  104 . As another example, power may be transferred wirelessly, such as via inductive or capacitive power transfer systems. 
     As noted above, the base portion  104  may include a top case  112 . The top case  112  may define or be part of an integrated interface system of the device  100 . For example, the top case  112  may define a top, exterior surface of the base portion  104 , and may be configured to receive touch inputs, force inputs, keyboard inputs, and the like. In some cases, the entire top surface of the top case  112  (or substantially all of the top surface) may be touch and/or force sensitive, and may detect touch inputs substantially anywhere along its top surface, including in a keyboard region as well as surrounding regions. In cases where the entire top case  112  is touch and force sensitive, numerous types of inputs are enabled via the top case  112 . For example, as described herein, touch inputs including cursor-control gestures may be applied anywhere on the top case, including on the keys of a virtual or mechanical keyboard. As another example, the addition of force sensing across a keyboard region as well as non-keyboard regions may facilitate the detection of typing inputs when multiple fingers are resting on a virtual keyboard, as the force sensing systems may allow the device to differentiate between a finger resting on a key versus a finger actually tapping or pressing on a key. 
     In addition to receiving or detecting inputs, the top case  112  may be configured to provide outputs to a user. For example, the top case  112  may include or be integrated with displays, light sources, haptic actuators, or the like, that provide outputs that are detectable via the top case  112  (e.g., at any location or substantially any location along a top surface of the top case  112 ). More particularly, a display may be configured to produce an image on the top case  112 , and a haptic actuator may be configured to move the top case  112  in a manner that is detectable by a user in contact with the top case  112 . The composition and configuration of the top case  112  may facilitate and integrate these (and other) input and output functions. For example, a continuous, nonconductive top case  112  (e.g., formed from a dielectric such as glass, plastic, ceramic, composites, or combinations of materials) may allow inputs to be detected through the top case  112  while also providing an effective platform for haptic and visual outputs. 
     The top case  112  may define or include input regions such as a keyboard region  114  and a touch-input region  116 . The keyboard region  114  may correspond to or include a virtual keyboard or a mechanical keyboard. Virtual keyboards are discussed herein with respect to  FIGS. 16A-17B , and mechanical keyboards are discussed herein with respect to  FIGS. 12A-15B and 33A-43C . 
     The top case  112  may define a continuous top surface of the base portion  104 , which may be the top exterior surface of the base portion  104 . A continuous top surface (and a continuous top case more generally) may refer to a surface or member that has no seams, openings, through-holes, or other discontinuities. In the context of the top case  112 , a continuous top case or continuous top surface may therefore lack seams, openings, through-holes, or other discontinuities in the portion of the top case  112  that forms an exterior top surface of the base portion  104 . More particularly, the top case  112  may lack openings for keys, keyboards, trackpads, buttons, or the like. The top case  112  may extend substantially to the outer edges of the base portion  104 . Accordingly, the top case  112  may prevent or reduce the possibility of liquid, dust, dirt, or other contaminants or debris from entering the base portion  104  through the top surface of the top case  112 . Also, the continuous surface provides a desirable aesthetic and a touch sensitive, haptic, and visual output surface that can utilize the entire exposed top surface of the top case  112 . 
     The top case  112  may be formed from or include a light-transmissive material, such as glass, plastic, or light-transmissive ceramics. In some cases, the top case  112  is a single member, such as a single glass member, a single plastic member, or a single member formed from or including any other suitable material. In other cases, the top case  112  may be formed from multiple members, either of the same material or different materials, that are bonded, adhered, joined, or otherwise coupled together to define the top case  112 . 
     In some cases, all or some of the top case  112  may be masked to form opaque regions. The masking may be formed using any suitable technique such as depositing an ink, dye, film, or otherwise positioning an opaque material below the top case  112  (and above any other components or layers that are intended to remain hidden or occluded). The masking or other opaque material or layer may be any desired color. Indeed, because the top case  112  may be light-transmissive (e.g., transparent), there may be fewer limitations on the achievable colors than with conventional devices. For example, certain colors, finishes, or other optical treatments may be difficult or impossible to achieve in an uncoated opaque plastic material. By using a light-transmissive or transparent top case  112 , it may be possible to achieve devices having many more available colors and/or finishes (e.g., mirror finishes, metal flake finishes, etc.). In some cases, images, photographs, paintings, or other graphic content may be visible through the light-transmissive top case  112 . 
     The touch-input region  116  may be configured to detect touch- and/or force-based inputs, and may be or may include any portion of the top case  112 , including substantially the entire top case  112 , including the keyboard region  114 , a trackpad region (e.g., the trackpad region  2003 ,  FIG. 20A ), a virtual key region (e.g., the virtual key region  1208 ,  FIG. 12A ), optional sidewalls of the top case (e.g., the sidewall  512   a - c ,  FIGS. 5A-5C ), or any other portion of the top case  112 . In some cases, substantially the entire top case  112 , from edge to edge, may define a touch-sensitive input region. In this way, and as discussed herein, touch or trackpad inputs, such as clicks, taps, gestures (e.g., swiping, pinching), and multi-touch inputs, may be detected on any portion of the top case  112 , including within the keyboard region  114 . Moreover, even where the keyboard region  114  includes mechanical key mechanisms, the touch-input region  116  may detect touch inputs (e.g., gestures) that are applied to the keycaps and not to the top case  112  directly. As used herein, a “key” may refer to a mechanical key, a virtual key (e.g., a key displayed by an underlying display), a key region (e.g., defined by a mask layer on a top case), or any other suitable type of key described herein, as well as any associated mechanisms, keycaps, or support structures. 
     The device  100 , and in particular the top case  112 , may also include or define output regions, such as visual-output regions and haptic-output regions. Haptic-output regions include regions of the top case  112  that move or can otherwise induce tactile sensations in a user. Visual-output regions include regions in which visual outputs are produced, such as regions associated with lights or displays (e.g., to display virtual and/or dynamic keys). Example visual- and haptic-output regions, as well as components for producing visual and haptic outputs, are described herein. 
     Thus, the device  100  may include a top case that defines an integrated interface system, which provides various input and output functions, including keyboard inputs, touch inputs, visual outputs, and haptic outputs. 
       FIG. 1B  is a simplified block diagram showing functional aspects of an example integrated interface system  118 . The functions of the integrated interface system  118  may be performed by any of the components and structures described herein, including touch sensors, force sensors, haptic actuators, displays, mechanical keys, light sources, and the like, examples of which are described herein. 
     With reference to  FIG. 1B , the integrated interface system  118  provides a keyboard input function  120 . The keyboard input function  120  includes the detection of key-based or similar inputs, including inputs that are typically provided via a keyboard (e.g., alphanumeric and/or symbolic character input, function key selections, arrow key selections). A device (e.g., the device  100 ) may use any suitable input mechanism(s) to perform the keyboard input function  120 , such as mechanical keys, touch sensors, force sensors, displays, or the like. Where the device includes mechanical keys or key mechanisms, the keyboard input function  120  includes the detection of physical movement of the key mechanisms. Where the device includes virtual keys, the keyboard input function  120  may include the detection of touch or force inputs on the virtual keys. In either case, the keyboard input function  120  may detect keyboard inputs through an input surface (such as the top case  112  in  FIG. 1A ). 
     The integrated interface system  118  also provides a touch input function  122 . The touch input function  122  includes the detection of touch-based inputs, such as clicks, taps, gestures (e.g., swiping, pinching), multi-touch inputs, or the like. These inputs may be similar to or include inputs conventionally detected by a trackpad. For example, these inputs may include gesture inputs that may be used to control a cursor or element of a graphical user interface on a display of the device. A device (e.g., the device  100 ) may use any suitable input mechanism(s), such as capacitive touch sensors, resistive touch sensors, acoustic wave sensors, or the like, to perform the touch input function  122 . Such mechanisms may be associated with or cover substantially the entire user-facing portion of the top case  112 . In this way, the touch input function  122  can detect touch inputs applied anywhere on the top case  112  (including, for example, on a mechanical or virtual keyboard, on a trackpad region below a mechanical or virtual keyboard, and/or on the portions of the top case that are adjacent the lateral sides of a mechanical or virtual keyboard). 
     The touch input function  122  may include the detection of touch inputs that are received in a keyboard region of the top case  112  (e.g., the keyboard region  114 ,  FIG. 1A ). The keyboard region may correspond to a keyless surface of a virtual keyboard, or it may correspond to a region of the top case  112  that includes mechanical keys, as described above. In either case, the touch input function  122  may include the detection of touch inputs, such as clicks, taps, gestures (e.g., swiping, pinching), and multi-touch inputs, that are applied to the keyboard region. Where mechanical keys or key mechanisms are used, the touch input function  122  may include the detection of touch inputs through the mechanical keys or mechanisms. 
     The touch input function  122  may also include the detection of touch inputs that are applied to a non-key region of the top case  112 . For example, any region of the top case  112  that does not correspond to a keyboard region (a non-keyboard region) may be configured to receive touch inputs, and the device may detect touch inputs in these regions as well. 
     The integrated interface system  118  also provides a force input function  128  that includes the detection of force inputs and/or a force component of a touch input. A device (e.g., the device  100 ) may use any suitable force sensors to provide the force input function  128 , such as the force sensors described herein with respect to  FIGS. 21A-24B . The force input function  128  may include the detection of force inputs at any location on the top case  112 . For example, substantially the entire top surface of the top case  112  may be configured to receive and/or detect force inputs applied to substantially any location of the top surface of the top case  112 . Further, where the top case  112  includes a dielectric surface or is formed from a dielectric sheet (e.g., glass, plastic, ceramic, or the like), the dielectric and/or mechanical properties (or other properties) of the dielectric material may facilitate the detection of force inputs at any suitable location on the top case (e.g., in a keyboard region  114 , a non-keyboard region, or any other suitable location). 
     The integrated interface system  118  also provides a display function  130  that includes the output of images or other visual information via the top case  112 . For example, a device (e.g., the device  100 ) may include or communicate with displays that are within the device  100  and that produce images viewable on the top case  112 , thereby providing the display function  130 . Displays may be used, for example, to produce images of keys (or other affordances) for the keyboard region  114 . Displays may also be used to define input regions, buttons, or other affordances anywhere on the top case  112  (e.g., to indicate the location and/or function of an input), or to display other graphical objects (e.g., images, videos, text, user interfaces, or the like). Because the top case  112  may be formed from a glass or other transparent material, displays may be integrated with the top case  112  such that the top case  112  acts as a screen, even on surfaces that in conventional computing devices are opaque, such as a trackpad or a portion bordering a keyboard. 
     The integrated interface system  118  also provides a haptic output function  132  that includes the production of haptic or tactile outputs at the top case  112 . A device (e.g., the device  100 ) may use haptic actuators, such as those discussed herein with reference to  FIGS. 25-30B , to perform the haptic output function  132 . The haptic actuators may be coupled to the top case  112  or otherwise cause the top case  112  to physically move to produce haptic outputs at the top case  112 . Haptic outputs may be used for various purposes, such as to indicate that a touch input (e.g., a key selection or a trackpad selection) has been detected by the device  100 . 
     The integrated interface system  118  also provides an illumination function  134  that includes the illumination of regions or elements of the top case  112 . A device (e.g., the device  100 ) may use light sources, such as those discussed herein with reference to  FIGS. 37A-40B , to provide the illumination function. For example, a glass, plastic, or otherwise light-transmissive top case (e.g., the top case  112 ) may act as a light guide. For example, a glass or light-transmissive (e.g., transparent or translucent) top case  112  may act as a light guide to direct light from a light source to other regions of the device  100 , such as under or around keycaps or other key mechanisms. Also, where the top case  112  is entirely transparent or has transparent portions, the transparent portions allow images from underlying displays to pass through the top case  112 , which would not be possible with opaque top cases. The illumination function  134  may also provide backlighting or other illumination for the displays. 
     The integrated interface system  118  also provides one or more additional input and/or sensor functions  129 . A device (e.g., the device  100 ) may use any suitable components to receive inputs (e.g., from a user or another computer, device, system, network, etc.) or to detect any suitable property or parameter of the device, the environment surrounding the device, people or things interacting with the device (or nearby the device), or the like. For example, a device may include accelerometers, temperature sensors, position/orientation sensors, biometric sensors (e.g., fingerprint sensors, photoplethysmographs, blood-oxygen sensors, blood sugar sensors, or the like), eye-tracking sensors, retinal scanners, humidity sensors, buttons, switches, lid-closure sensors, or the like. Such sensors and/or input devices may be located in any suitable portion of or location in the device. For example, sensors and/or input devices maybe located in the display portion  102  or the base portion  104  (or it may include components in both the display portion  102  and the base portion  104 ). An input and/or sensor function  129  may use network and/or communications systems to provide input and/or sensing functionality, such as to receive commands, data, information, content (e.g., audio, video, images, webpages), or the like, from other devices or systems. 
       FIG. 2A  is a partial exploded view of the device  100 . As described above, the device  100  includes a top case  112  that forms part of the enclosure defining the base portion  104 , and also defines a top exterior surface of the base portion  104 , which may also act as an input surface of an integrated interface system for receiving user input. As shown in  FIG. 2A , the base portion  104  is pivotally coupled to a display portion  102  to form a foldable or clam-shell type notebook computer. 
     As shown in  FIG. 2A , the display portion  102  includes a display  204  coupled to the display housing  108 . The display  204  may include various display components, such as liquid crystal display (LCD) components, light source(s) (e.g., light emitting diodes (LEDs), organic LEDs (OLEDs)), filter layers, polarizers, light diffusers, covers (e.g., glass or plastic cover sheets), and the like. More particularly, in some cases, the display  204  includes a display stack (including, for example, an LCD, polarizing films, light diffusing films, and/or a back or side light) and a cover disposed over the display stack and forming an exterior, user-facing surface of the display  204 . In other cases, the display  204  includes a display stack as described above, but does not include a separate cover. In such cases, a side or surface of the LCD panel of the display stack may form the exterior, user-facing surface of the display  204 . The display portion  102  may also include other components such as structural components that support any of the aforementioned components, batteries, wired or wireless communication components, processors, memory, or the like. 
     The display portion  102  may include mechanisms  103 , or portions thereof, coupled to or integrally formed with the display portion  102 . For example, the display housing  108  may include hinges (or portions thereof) welded, brazed, adhered, or otherwise attached to the display housing  108 . The display  204  and the top case  112  may include features  206  (such as the notches shown in  FIG. 2A ) to allow for the placement of the mechanisms  103  while allowing the display  204  and the top case  112  to define substantially the entire user interface surfaces of the display portion  102  and the base portion  104 . 
     The base portion  104  may include a bottom case  110  and the top case  112 , described above, which together define an interior volume of the base portion  104 . The base portion  104  may also include components  208  within the interior volume, such as processors, memory devices, circuit boards, input/output devices, haptic actuators, wired and/or wireless communication devices, communication ports, disk drives, and the like. As described above, the top case  112  may be a continuous surface (e.g., having no holes or openings in its top surface) to prevent or limit ingress of liquid, debris, or other contaminants into the interior volume, thereby reducing the chance of damage to the components  208 . 
     The bottom case  110  may include a bottom member  111  and one or more sidewalls  113 - 1  through  113 - 4 . In some cases, the bottom case  110  has one, two, three, or four sidewalls. Where the bottom case has three sidewalls, the sidewall  113 - 3  may be omitted. Where the bottom case has two sidewalls, the sidewalls  113 - 2 ,  113 - 4  may be omitted. Where the bottom case has one sidewall, the sole sidewall may be the sidewall  113 - 1 . Of course, other configurations of sidewalls are also possible. 
     The bottom case  110  may be formed from or include any suitable material. For example, the bottom case  110  may be formed from or include metal (e.g., steel, aluminum, titanium), glass, plastic, ceramic, composite, or any other suitable other material or combination of these or other materials. In some cases, the bottom case  110  is a single (e.g., monolithic) component or member, such as a single sheet of glass, metal, plastic, or the like. For example, the bottom case  110  may be a single component formed from a single piece of metal, and may be formed by stamping, drawing, machining, hydroforming, molding, or any other suitable process. Where the bottom case  110  is a single component, the bottom member  111  and the sidewall(s)  113  may be an integral structure (e.g., a monolithic component). 
     The top case  112  may be coupled to the bottom case  110  in any suitable way. Various examples of the coupling between the top case  112  and the bottom case  110 , as well as various configurations and shapes of the top and bottom cases  112 ,  110  are described herein. Similarly, example configurations of the display  204  and the display housing  108  (and techniques for joining them) are described herein. 
       FIGS. 2B-2F  are cross-sectional views of the base portion  104 , viewed along section A-A in  FIG. 1A , illustrating example placements of the components  208  within the base portion  104 . As shown in  FIG. 2B , components  208   b  may be coupled to the bottom case  110 . Some of the components  208   b  may contact the top case  112  without being attached or fixed to the top case  112 . Alternatively, the components  208   b  may be separated from the top case  112  by a space or a layer of material, or they may be coupled to both the bottom interior surface of the top case and the top interior surface of the bottom case. 
     In another example shown in  FIG. 2C , components  208   c  may be coupled to the top case  112 . The components  208   c  may be set apart from the bottom case  110  by a space (as shown), or some or all of the components  208   c  may contact the bottom case  110  without being attached or fixed to the bottom case  110 . 
     In another example shown in  FIG. 2D , first components  210  (e.g., a first subset of the components  208 ,  FIG. 2A ) may be coupled to the top case  112 , while second components  212  (e.g., a second subset of the components  208 ,  FIG. 2A ) may be coupled to the bottom case  110 . The first components  210  may include components that facilitate input and output functionality via the top case  112 , such as haptic actuators, displays, touch sensors, force sensors, and the like. The second components  212  may include other components, such as batteries, processors, circuit boards, communication ports, or the like. Other component distributions and configurations are also contemplated. 
     The first and second components  210 ,  212  may be positioned so that they do not interfere with one another when assembled. For example, as shown in  FIG. 2D , the second components  212  are configured to fit in a space defined between the first components  210 . This allows effective utilization of the interior volume of the base portion  104 , and may reduce one or more dimensions (e.g., the height) of the base portion  104  as compared to other component placements. 
       FIG. 2E  shows the example component arrangement of  FIG. 2D , with a potting material  211  disposed between the top and bottom cases  110 ,  112  and filling the spaces between the components  210 ,  212 . Potting may be used to refer to a material that is disposed in a volume or region as a liquid, foam, or other flowable state, and then cured to a non-flowable state (e.g., a solid). The potting may be formed from an insulating or dielectric material to prevent shorting of or interference with internal electrical components. Example potting materials include but are not limited to polyurethane, silicone, epoxy, or the like. 
     The potting material  211  may support the top case  112  and may help reduce or prevent deflection of the top case  112  in response to applied forces, such as forces associated with touch inputs, force inputs, keyboard inputs, trackpad inputs, hands resting on the top case  112 , and the like. The potting material  211  may be any suitable material, such as silicone, epoxy, polyurethane, aerogel, or any other suitable polymer or other material.  FIG. 2E  shows the potting material  211  occupying all of the otherwise empty space between the top and bottom cases  110 ,  112 . In other examples, such as the example shown in  FIG. 2F , the potting material  211  may occupy less than all of the otherwise empty space, such that gaps, openings, air pockets/bubbles, cavities, or the like are present in the base portion  104 . In such cases, there may be multiple discrete pieces or volumes of potting material  211  (e.g., pillars  214 ) in the base portion  104 . 
     Components  208   b ,  208   c ,  210 , and  212  may correspond to the components  208  shown in  FIG. 2A , or they may be different components. Also, the placements of the components shown in  FIGS. 2B-2F  are merely examples, and other configurations and placements of the components may also be used. For example, some of the components (or portions thereof) may be positioned between the top case  112  and the bottom case  110  without contacting either the bottom interior surface of the top case  112  or the top interior surface of the bottom case  110 . Such components may be coupled to a side surface or wall of the bottom case  110 , for example. 
       FIG. 3A  is a partial exploded view of the base portion  104 , showing the top case  112  separated from the bottom case  110 .  FIG. 3B  is a partial cross-sectional view of the base portion  104 , viewed along section B-B in  FIGS. 1A and 3A . The components  208  ( FIG. 2A ) of the device  100 , which are disposed in the interior volume between the top case  112  and the bottom case  110  are omitted from  FIGS. 3A-3B  for clarity. As shown, the top case  112  is coupled to the bottom case  110  to define an interior volume  300  of the base portion  104 .  FIGS. 3A-3B  are schematic illustrations of the structural integration of the top case  112  and the bottom case  110 , while  FIGS. 4A-5D  illustrate several example embodiments. 
       FIG. 4A  is a partial cross-sectional view of a base portion  400   a  of a computing device (which may correspond to the base portion  104 ,  FIG. 1A ), viewed along section B-B in  FIG. 3A , showing an example configuration of a bottom case  406   a  and a top case  404   a  (which may correspond to the bottom case  110  and the top case  112 , respectively). The top case  404   a  may be attached to the bottom case  406   a  via sidewalls of the bottom case  406   a . For example, a portion of a bottom surface  405   a  of the top case  404   a  is coupled to a top of a sidewall  410   a  of the bottom case  406   a  via a joining member  414 . As shown, the top case  404   a  may extend to the outer edge of the bottom case  406   a , and an edge or side  408  of the top case  404   a  may form a portion of the side of the base portion  400   a . The top case  404   a  may have a rounded or contoured transition (e.g., a filleted corner or edge) from a top surface  407   a  of the top case  404   a  to the edge or side  408  of the top case  404   a . The rounded or contoured transition may define part of a smooth continuous surface that includes the rounded or contoured transition and at least part of the side of the bottom case  406   a . In other cases, the top case  404   a  may have any other appropriate shape, such as a substantially perpendicular angle (as shown), a chamfered edge, or the like. A filleted or chamfered edge may resist chipping, cracking, or other damage to the top case  404   a , and may also provide an attractive or desired appearance and tactile feel of the base portion  400   a.    
     The joining member  414  may be any appropriate material or combination of materials. The joining member  414  may be an adhesive, such as a pressure sensitive adhesive (PSA), heat sensitive adhesive (HSA), epoxy, cyanoacrylate, or any other suitable adhesive. In addition to securing the top case  404   a  to the bottom case  406   a , the joining member  414  may also act as a seal between the top case  404   a  and the bottom case  406   a , preventing material (e.g., liquids, dust, or other contaminants) from entering the base portion  400   a.    
     In some cases, the joining member  414  may be substantially rigid, such that the distance between the interfacing surfaces of the top case  404   a  and the bottom case  406   a  does not change substantially when a force is applied to the top case  404   a  (e.g., as a result of typing or other input forces applied to the top case  404   a ). Alternatively, the joining member  414  may be formed from or may include a compliant material, such as a foam, rubber, polyurethane, or other suitable material, that allows the top case  404   a  to move relative to the bottom case  406   a  in response to application of force on the top case  404   a  and/or the bottom case  406   a . Such forces may be in response to user inputs (e.g., typing or interacting with a trackpad), they may be produced by haptic actuators, they may be due to the device being dropped or objects being dropped on the device, or the like. Moreover, such forces may be compressive or tensile forces, shear forces, or the like. As described herein, compliant materials may be used for the joining member  414  in order to allow a haptic actuator to more easily move the top case  404   a  relative to the bottom case  406   a  (as compared to more rigid joining members), thereby providing greater efficiency in transferring haptic outputs through the top case  404   a  to a user. 
     A compliant joining member  414  may be used where force sensors determine an amount of force applied to the top case  404   a  based on the amount of deflection or movement of the top case  404   a  relative to the bottom case  406   a . Such force sensors, or components thereof, may be incorporated in the joining member  414 . For example, electrodes for detecting changes in capacitance due to deflection of the top case  404   a  relative to the bottom case  406   a  may be included in the joining member  414 . 
     The joining member  414  may be a single piece of material (e.g., a single layer of adhesive), or it may include multiple components, layers, or other elements. For example, a multiple layered joining member  414  may include a compliant member positioned between (and bonded to) two adhesive layers, with the first adhesive layer bonding to the top case  404   a  and the second adhesive layer bonding to the bottom case  406   a . Part of the joining member may form part of the side (e.g., the exterior surface) of the base portion, as shown in  FIG. 4A . 
     As shown in  FIG. 4A , the bottom case  406   a  includes a sidewall  410   a  extending away (or upward, as shown in  FIG. 4A ) from a bottom member  412   a  (which may be similar to or an embodiment of the bottom member  111 ,  FIGS. 3A-3B ). Thus, the bottom case  406   a  defines at least a bottom and a side of an interior volume of the base portion  400   a , and the top case  404   a  defines a top of the interior volume. In some cases, a bottom case (e.g., the bottom case  406   a ) includes multiple sidewalls that define the exterior sides and/or side surfaces of a base portion of a device. For example,  FIG. 3A  shows a bottom case  110  that includes first, second, third, and fourth sidewalls extending around the front, left, right, and back areas of the base portion. The sidewalls may be integrally formed with the bottom member (e.g., the bottom member  412   a ) of the bottom case. The bottom case (e.g., the bottom case  110 ,  406   a , or any other bottom case described herein) may be formed of a single piece of metal, glass, ceramic, or the like. In some cases, the bottom case (including a bottom surface and one, two, three, or four sidewalls) may be a metal member, which may be machined or otherwise formed from a single piece of metal. Other configurations are also possible, such as configurations where the top case defines the top and sides of the interior volume, and the bottom case defines the bottom of the interior volume. Examples of such configurations are discussed herein. 
     The top case  404   a , the bottom case  406   a , and the joining member  414  may have a substantially similar appearance. For example, these components may be configured to have the same or similar color, texture, tactile feel, etc. This may include applying paint, ink, dye, or other coatings to the components, and/or applying the same finishing processes (e.g., machining, polishing, etc.) to the components. 
       FIG. 4B  is a partial cross-sectional view of a base portion  400   b  of a computing device (which may correspond to the base portion  104 ,  FIG. 1A ), viewed along section B-B in  FIG. 3A , showing another example configuration of a bottom case  406   b  and a top case  404   b . The top case  404   b  and the bottom case  406   b  each define corresponding stepped interface regions. In particular, the top case  404   b  may define a first interface surface  420  and a second interface surface  422  that is offset from (e.g., not in the same plane as) the first interface surface  420 . Correspondingly, the bottom case  406   b  may define a third interface surface  424  that is opposite the first interface surface  420 , and a fourth interface surface  426  that is opposite the second interface surface  422 . 
     The first and third interface surfaces  420 ,  424  may be coupled to one another via a first joining member  416 , and the second and fourth interface surfaces  422 ,  426  may be coupled to one another via a second joining member  418 . The first and second joining members  416 ,  418  may be similar in structure, material, function, etc., to the joining member  414  discussed above. The first and second joining members  416 ,  418  may be substantially identical to one another, or they may be different. For example, the first joining member  416  may have a different stiffness than the second joining member  418 . As another example, the first joining member  416  may form a better seal (e.g., to prevent ingress of liquids or other contaminants), while the second joining member  418  may be less effective at sealing but may provide a stronger bond or holding force as compared to the first joining member  416 . As yet another example, the first joining member  416  may lack force sensors or force sensing components, while the second joining member  418  may include electrodes or other components to act as a force sensor (or a portion of a force sensor). Other optimizations are also possible, and each joining member may be selected or optimized for any desirable or suitable property or combination of properties. Examples of properties that may be selected or optimized for include strength, hardness, scratch resistance, chemical resistance, ultraviolet radiation resistance, water resistance, bond strength, color, surface finish, machinability, and the like. 
       FIG. 4C  is a partial cross-sectional view of a base portion  400   c  (which may correspond to the base portion  104 ,  FIG. 1A ), viewed along section B-B in  FIG. 3A , showing an example configuration of a bottom case  406   c  and a top case  404   c . The top case  404   c  may be coupled to the bottom case  406   c  via a joining member  428 , which may be similar in structure, material, function, etc., to the joining member  414  discussed above. 
     The top case  404   c  may not extend all the way to the edge  432  of the bottom case  406   c . For example, an edge  432  of the top case  404   c  may be recessed relative to the exterior side of the bottom case  406   c . An edge trim  430  may be disposed on and/or attached to the edge  432  of the top case  404   c , and may substantially surround the top case  404   c  along the edge  432  (e.g., it may be applied to all otherwise exposed edges of the top case  404   c ). The edge trim  430  may be formed from or include any suitable material or materials. For example, the edge trim  430  may be epoxy, plastic, paint, ink, dye, a rubber coating or strip, or the like. The edge trim  430  may be a single material that is adhered to the top case  404   c  and/or the bottom case  406   c , or it may comprise multiple elements or materials, such as a trim material and a separate adhesive. 
     The edge trim  430  may protect the edge of the top case  404   c  from scratches, chips, or other damage. The edge trim  430  may also prevent light from entering or leaving the top case  404   c  through the edge  432 . For example, the top case  404   c  may be used as a light guide or light pipe for illuminated components, such as keycaps, integrated displays, or the like. In such cases, the edge trim  430  may prevent light leaks from the edge  432 . Where the top case  404   c  is a light guide or light pipe, the edge trim  430  may include or be applied over a reflective material or coating that is disposed on the edge  432  and that is configured to reflect light back into the top case  404   c.    
     The edge trim  430  may be configured to have a similar appearance to the bottom case  406   c . For example, the edge trim  430  may have the same or similar color, texture, tactile feel, or other property as the bottom case  406   c . Accordingly, the side of the base portion  400   c  may have a consistent appearance, and may appear to be formed from a single component (or the edge trim  430  and the bottom case  406   c  may appear to be formed from the same material). The edge trim  430  and the bottom case  406   c  may be subjected to a common finishing process, such as polishing, grinding, or machining, to produce similar textures and appearances on both components. For example, the same polishing step may be applied to the edge trim  430  and the bottom case  406   c  after these components are assembled. In some cases, the same tool (e.g., a polishing tool) may be applied to the edge trim  430  and the bottom case  406   c  substantially simultaneously. 
       FIG. 4D  is a partial cross-sectional view of a base portion  400   d  (which may correspond to the base portion  104 ,  FIG. 1A ), viewed along section B-B in  FIG. 3A , showing an example configuration of a bottom case  406   d  and a top case  404   d . The top case  404   d  may be coupled to the bottom case  406   d  via multiple joining members. The first and second joining members  434 ,  438  may be applied first to define a trough or cavity in which a third joining member  436  may be positioned. In some cases, the first and second joining members  434 ,  438  may be an adhesive foam, tape, film, or other material that may be applied in solid or semi-solid form to define the trough or cavity. After the first and second joining members  434 ,  438  are applied and the trough or cavity is defined, the third joining member  436  may be introduced into the trough or cavity. For example, the third joining member  436  may be a curable adhesive in a liquid or other flowable form that is poured, injected, or otherwise introduced into the trough or cavity defined by the first and second joining member  434 ,  436 . (The trough or cavity may be continuous around a joining surface of the top case  404   d  or bottom case  406   d , and may fully contain the flowable material of the third joining member  436  in a desired location or position.) After the third joining member  436  is introduced into the trough or cavity, the top case  404   d  and the bottom case  406   d  may be brought together and bonded to one another by the joining members (e.g., by allowing any or all of the joining members  434 ,  436 ,  438  to cure and/or harden. 
     In some cases, the first, second, and third joining members  434 ,  438 , and  436  may have different physical and/or mechanical properties. For example, the first and second joining members  434 ,  438  may be in a solid or semi-solid form and may have a dimensional stability such that the size or shape does not change significantly after being applied to the top case  404   d  and/or bottom case  406   d . Accordingly, they may be used to define a physical and/or dimensional relationship between the top and bottom cases  404   d ,  406   d  (e.g., to maintain a specified distance therebetween), as well as to define the trough or cavity in which the material for the third joining member  436  may be introduced. The first and second joining members  434 ,  438  may also adhere or otherwise secure the top case  404   d  to the bottom case  406   d . Instead of or in addition to using the first and second joining members  434 ,  438  to define or maintain the distance between the top and bottom cases  404   d ,  406   d , spacers may be positioned between the top and bottom cases  404   d ,  406   d . Spacers may be any suitable material, such as foam, tape, film, solidified/cured adhesive, or the like. Spacers may be any suitable shape, such as pillars, disks, domes, etc., and may be positioned at spaced intervals along the interface between the top and bottom cases  404   d ,  406   d.    
     The third joining member  436  may be a high shear adhesive (or any other suitable adhesive or material), and as such may provide a high-strength adhesive bond between the top case  404   d  and the bottom case  406   d  and may prevent or reduce delamination or detachment or relative movement of the top and bottom cases  404   d ,  406   d . High shear adhesives may have a higher resistance to shear loads than other adhesives. 
       FIG. 4E  is a partial cross-sectional view of a base portion  400   e  (which may correspond to the base portion  104 ,  FIG. 1A ), viewed along section B-B in  FIG. 3A , showing an example configuration of a bottom case  406   e  and a top case  404   e . The top case  404   e  may be coupled to the bottom case  406   e  via a joining member  440 . The joining member  440  may be formed from a liquid or flowable adhesive that is introduced into a trough or cavity defined by walls  442 ,  444  of the bottom case  406   e . As shown, the walls  442 ,  444  are integral with the bottom case  406   e . For example, the trough or cavity may be machined (or laser ablated or otherwise formed) into the bottom case  406   e  to form the walls  442 ,  444 . Alternatively, the walls  442 ,  444  may be separate components from the bottom case  406   e  and may be secured (e.g., welded, bonded, adhered, etc.) to the bottom case  406   e  to form the walls  442 ,  444 . As noted above, the joining member  440  may be formed by flowing, injecting, or otherwise introducing an adhesive (e.g., a high shear adhesive or any other suitable adhesive) into the space between the walls  442 ,  444 . Where the joining member  440  is formed from a liquid or flowable material, the walls  442 ,  444  may contain the flowable material in place so that it can adequately bond to the top and bottom cases  404   e ,  406   e.    
       FIG. 4F  is a partial cross-sectional view of a base portion  400   f  (which may correspond to the base portion  104 ,  FIG. 1A ), viewed along section B-B in  FIG. 3A , showing an example configuration of a bottom case  406   f  and a top case  404   f . The bottom case  406   f  may define a surface or ledge  448 , with a portion of a sidewall of the bottom case  406   f  extending past the ledge  448  and defining a flange  446 . The top case  404   f  may rest on or otherwise interface with the ledge  448 , and the flange  446  may be adjacent a peripheral side of the top case  404   f , as shown in  FIG. 4F . In some cases, the flange  446  may extend above or past the ledge  448  by a distance that is substantially the same as the thickness of the top case  404   f  (e.g., the height of the peripheral side of the top case  404   f ), such that the top surface of the flange  446  (as viewed in  FIG. 4F ) is substantially flush or even with the top surface of the top case  404   f . The top case  404   f  may be affixed or secured to the bottom case  406   f  with adhesive, or any other suitable bonding technique or material. 
       FIGS. 4A-4F  show techniques for joining an example top case to an example bottom case. Any of the techniques, joining materials, top and bottom case geometries, and the like, may equally apply to other example top and bottom cases, such as top and bottom cases with different geometries (e.g., different wall thicknesses, different shapes, different wall angles, different sizes), different materials, different physical properties, or the like. For example, the teachings shown and described with respect to  FIGS. 4A-4F  may be used with top and bottom cases as shown in  FIGS. 2A-2F . 
       FIGS. 5A-5D  are partial cross-sectional views of base portions of a computing device in which the top cases include a top member that forms a top surface of the base portion as well as a sidewall that forms a side of the base portion.  FIGS. 5A-5D  show different configurations of an interface and coupling between a bottom case and a top case where the top case includes the sidewalls, rather than the bottom case. 
       FIG. 5A  is a partial cross-sectional view of a base portion  500   a  of a computing device (which may correspond to the base portion  104 ,  FIG. 1A ), viewed along section B-B in  FIG. 3A . As noted above, a top case  504   a  of the base portion  500   a  includes a top member  510   a  and a sidewall  512   a . The sidewall  512   a  may extend substantially perpendicularly from the top member  510   a , or it may extend at a different angle. The sidewall  512   a  defines an exterior side surface of the base portion  500   a . While one sidewall is shown, it will be understood that the top case  504   a  (as well as other top cases described herein) may include multiple sidewalls, such as one, two, three, or four (or more) sidewalls. In some cases, the top cases described herein include three sidewalls that are integrally formed with a top member (e.g., the top member  510   a ) to form front, left, and right sides of a base portion of an electronic device. The sidewalls may also be continuous along the corners between two sidewalls, producing in some cases a continuous band of sidewall that extends along at least three sides of the base portion. Features of any of the sidewalls described herein may be applied to other sidewalls as well. For example, while  FIG. 5A  shows a cross section of one sidewall, some or all other sidewalls of the top case  504   a  (which may correspond to and/or replace the sidewalls  113  in  FIGS. 3A-3B ) may have similar features and be coupled to the bottom case  506   a  in a similar way. 
     The top case  504   a  may be formed from any suitable material, such as glass, ceramic, metal, plastic, or the like. For example, the top case  504   a  may be a single piece of glass that has been molded (e.g., slumped) to form the top member  510   a  and the sidewall  512   a . The single, continuous glass (or other material) top case may be devoid of upward facing seams, holes, openings, or the like, thus forming a highly spill-resistant base portion. 
     The top case  504   a  may include one or more openings in the sidewalls (e.g., the sidewall  512   a ) to allow access to interior components of the device. For example, a device may include connectors (e.g., for charging, communications, and the like), and the top case  504   a  may include openings to allow cables or other components to connect to the connectors. Example connectors include universal serial bus (USB) connectors, card readers, power cable connectors, and the like. The opening(s) may have other functions or be associated with other components as well. For example, an opening may correspond to a disk drive to allow a disk (e.g., a DVD or CD) to be inserted into the drive, or an opening may be used for a fastener (e.g., a screw, bolt, etc.) to secure the top case  504   a  to another component (e.g., a bottom case  506   a ). 
     Openings may be formed in the sidewalls (or other portions) of the top case  504   a  in any suitable way. For example, openings may be machined, laser cut, plasma cut, sawed, chemically etched, or the like. Openings may also be formed into the top case  504   a  during a molding process, thus reducing or eliminating the need to form the openings after the top case  504   a  is formed and hardened. 
     The top case  504   a  is coupled to a bottom case  506   a  via a joining member  508   a . The bottom case  506   a  forms a bottom of an interior volume of the base portion  500   a , and may be formed from any suitable material, such as metal, glass, plastic, ceramic, or the like. 
     The sidewall  512   a  of the top case  504   a  may be coupled to a top surface of the bottom case  506   a  such that an edge  514   a  of the bottom case  506   a  is substantially flush with the exterior surface of the sidewall  512   a . Accordingly, the edge  514   a  of the bottom case  506   a  defines part of the exterior side surface of the base portion  500   a.    
     The joining member  508   a  couples the top case  504   a  to the bottom case  506   a . The joining member  508   a  may be the same or similar in structure, material, function, etc., to the joining member  414  described above. 
       FIG. 5B  is a partial cross-sectional view of a base portion  500   b  of a computing device (which may correspond to the base portion  104 ,  FIG. 1A ), viewed along section B-B in  FIG. 3A . The base portion  500   b  includes a top case  504   b  coupled to a bottom case  506   b  via a joining member  508   b . The joining member  508   b  may be the same or similar in structure, material, function, etc., to the joining member  414  described above. 
     The base portion  500   b  is similar to the base portion  500   a  in that the top case  504   b  includes both a top member  510   b  and a sidewall  512   b , while the bottom case  506   b  is substantially flat. In the base portion  500   b , however, an edge of the bottom case  506   b  does not extend to the exterior surface of the sidewall  512   b . Rather, an edge of the bottom case  506   b  is coupled to an interior side of the sidewall  512   b , and the bottom case  506   b  does not form part of the exterior side of the base portion  500   b.    
       FIG. 5C  is a partial cross-sectional view of a base portion  500   c  of a computing device (which may correspond to the base portion  104 ,  FIG. 1A ), viewed along section B-B in  FIG. 3A . The base portion  500   c  includes a top case  504   c  coupled to a bottom case  506   c  via a joining member  508   c . The joining member  508   c  may be the same or similar in structure, material, function, etc., to the joining member  414  described above. 
     The base portion  500   c  is similar to the base portion  500   b  in that the top case  504   c  includes both a top member  510   c  and a sidewall  512   c , while the bottom case  506   c  does not extend to or form part of the exterior side surface of the base portion  500   c . However, in the base portion  500   c , the bottom case  506   c  is received in a notch  516  in the sidewall  512   c . The notch  516  allows a top surface of the bottom case  506   c , rather than or in addition to an edge of the bottom case  506   c , to interface with and/or be coupled to the sidewall  512   c.    
     In the foregoing examples, the top cases are shown having substantially sharp edges (e.g., sharp 90 degree angles where the top and side surfaces meet). However, these depictions should not be taken as limiting to the shapes and/or configurations of the top cases described herein. Indeed, the top cases may have other shapes and/or edge profiles. For example,  FIG. 5D  is a partial cross-sectional view of a base portion  500   d  of a computing device (which may correspond to the base portion  104 ,  FIG. 1A ), viewed along section B-B in  FIG. 3A . The base portion  500   d  includes a top case  504   d  coupled to a bottom case  506   d  via a joining member  508   d . The joining member  508   d  may be the same or similar in structure, material, function, etc., to the joining member  414  described above. 
     In  FIG. 5D , the top case  504   d  has an edge  518  that has a rounded, curved, or radiused profile. The radius may be any suitable radius, such as about 0.25 mm, about 0.5 mm, about 1.0 mm, or any other suitable radius. In some cases, the edge  518  may have a curved profile that follows a spline or curve that is not defined by a single radius. Other edge shapes are also contemplated, such as chamfers, coves, steps, or any other suitable shape. 
       FIGS. 6A-6G  are partial cross-sectional views of display portions of a computing device, viewed along section C-C in  FIG. 1A , illustrating various configurations of a display portions. The display portions depicted in  FIGS. 6A-6G  may define internal volumes for holding display components (or other components of a computing device), including backlights, side lights, covers, display stacks, LED layers, OLED layers, circuit boards, batteries, processors, memory, antennas, and the like. In  FIGS. 6A-6G , the display housings (e.g., the display housings  602   a - g ) may be similar in structure, material, function, etc., to the display housing  108  discussed above. Similarly, the joining members (e.g., the joining members  606   a - 606   g ) that join covers and/or displays to the display housings may be similar in structure, material, function, etc., to the joining member  414  (or any other joining members) discussed above. 
       FIG. 6A  depicts a partial cross-sectional view of a display portion  600   a  in which a cover  604   a  is coupled to a display housing  602   a . The cover  604   a  may be a transparent protective sheet that is in front of and optionally bonded or adhered to a display stack  607   a . The cover  604   a  may be formed from or include any suitable material, such as glass, plastic, ceramic, polycarbonate, etc. The cover  604   a  may be a single (e.g., monolithic) component, such as a single sheet of glass, plastic, or ceramic, or it may comprise multiple components or layers, such as multiple layers of glass, plastic, filters, coatings, or the like. The display stack  607   a  may include any suitable components, including LED layers, OLED layers, light diffusers, light guides, light sources, reflectors, polarizers, filters, or the like. While the display stack  607   a  is shown in  FIG. 6A  as a single component, it will be understood that the display stack  607   a  may have multiple components and/or layers. 
     As shown in  FIG. 6A , the cover  604   a  may extend to and form part of an exterior side of the display portion  600   a . In this configuration, the entire user-facing surface  609  of the display portion  600   a  may be defined by a single surface, without any visible bezel, frame, or other surrounding component. For example, the display housing  602   a  may not be visible around the outer perimeter of the cover  604   a  during normal operation of the computing device (e.g., when the computing device is in use and/or the display is being viewed by a user). 
     The cover  604   a  and the display housing  602   a  may be formed from or may include the same material. For example, the cover  604   a  may be formed from or may include a glass, and the display housing  602   a  may also be formed from glass (e.g., the same or a different glass than the cover  604   a ). Alternatively, the cover  604   a  and the display housing  602   a  may be formed from different materials. For example, the display housing  602   a  may be aluminum (or another metal), while the cover  604   a  may be formed from or include glass. 
     The cover  604   a  may be attached to the display housing  602   a  via a joining member  606   a . The joining member  606   a  may be or may include an adhesive that bonds the cover  604   a  to the display housing  602   a . The cover  604   a , display housing  602   a , and joining member  606   a  may have a substantially similar appearance. For example, these components may be configured to have the same or similar color, texture, tactile feel, etc. This may include applying paint, ink, dye, or other coatings to the components, and/or applying the same finishing processes (e.g., machining, polishing, etc.) to the components. 
       FIG. 6B  depicts a partial cross-sectional view of a display portion  600   b  in which a cover  604   b  is coupled to a display housing  602   b . The cover  604   b  is attached to the display housing  602   b  via a joining member  606   b . The display portion  600   b  also includes a display  607   b , which may be similar in structure, material, function, etc., to the display  607   a  discussed above. 
     The cover  604   b  may extend substantially to the edge of the display housing  602   b , except that an edge trim  608   b  may be disposed on and/or attached to an edge  612  of the cover  604   b . The edge trim  608   b  may cover the edge  612  of the cover  604   b  and the joining member  606   b , and may protect these components from damage. The edge trim  608   b  may also prevent light from entering or leaving the cover  604   b  through the edge  612 . Furthermore, in instances where the cover  604   b  includes multiple layers, the edge trim  608   b  may cover the ends or edges of the layers. This may improve the appearance of the display portion  600   b  (by covering unsightly seams) and may help prevent delamination or other damage to the multiple layers of the cover  604   b . The edge trim  608   b  may be similar in structure, material, function, etc., to the edge trim  430  discussed above. 
     The edge trim  608   b  may be configured to have a similar appearance to the display housing  602   b . For example, the edge trim  608   b  may have the same or similar color, surface texture, tactile feel, or other property as the display housing  602   b . Accordingly, the side of the display portion  600   b  may have a consistent appearance, and may appear to be formed from a single component (or the edge trim  608   b  and the display housing  602   b  may appear to be formed from the same material). The edge trim  608   b  and the display housing  602   b  may be subjected to a common finishing process, such as polishing, grinding, or machining, to produce similar textures and appearances on both components. For example, the same polishing step may be applied to the edge trim  608   b  and the display housing  602   b  after these components are assembled. In some cases, the same tool (e.g., a polishing tool) may be applied to the edge trim  608   b  and the display housing  602   b  substantially simultaneously, or during a common processing operation. 
       FIG. 6C  depicts a partial cross-sectional view of a display portion  600   c  in which a cover  604   c  is coupled to a display housing  602   c . The cover  604   c  is attached to the display housing  602   c  via a joining member  606   c . The display portion  600   c  also includes a display  607   c , which may be similar in structure, material, function, etc., to the display  607   a  discussed above. 
     As shown in  FIG. 6C , the cover  604   c  may be set into the display housing  602   c  (e.g., portions of the display housing  602   c  at least partially extend over a side of the cover  604   c ). In some cases, an exterior surface of the cover  604   c  may be substantially flush with an edge  614   c  of the display housing  602   c . In this configuration, the edge  614   c  (and optionally the joining member  606   c ) may define a bezel or frame that surrounds or frames at least part of the cover  604   c . Moreover, the part of the display housing  602   c  that surrounds the edges of the cover  604   c  may protect the edges of the cover  604   c  from chips, breaks, contaminants, or other potential damage. 
       FIG. 6D  depicts a partial cross-sectional view of a display portion  600   d  in which a cover  604   d  is coupled to a display housing  602   d . The display portion  600   d  also includes a display  607   d , which may be similar in structure, material, function, etc., to the display  607   a  discussed above. 
     The cover  604   d  is attached to the display housing  602   d  via a joining member  606   d . The display housing  602   d  includes a notched region that defines a shelf  616   d  to which the cover  604   d  is attached (via the joining member  606   d ). This configuration allows the cover  604   d  to be at least partially surrounded or framed (around its outer edge) by an edge  618   d  of the display housing  602   d , similar to the configuration in the display portion  600   c  ( FIG. 6C ), without a joining member that is visible on a user-facing, exterior surface  620  of the display portion  600   d . For example, the joining member  606   d  couples the interior or back surface of the cover  604   d  to the shelf  616   d . Accordingly, the joining member  606   d  does not form part of the surface  620 . 
     The shelf  616   d  shown in  FIG. 6D  also allows the cover  604   d  to be secured by the display housing  602   d  along multiple directions. For example, the cover  604   d  may engage the display housing  602   d  along the outer edge of the cover  604   d  and along a perimeter of a back surface of the cover  604   d . Accordingly, the cover  604   d  is retained along an in-plane direction and along an out-of-plane direction. This may improve the strength, rigidity, and/or durability of the display portion  600   d.    
       FIG. 6E  depicts a partial cross-sectional view of a display portion  600   e  in which a display stack  624   e  is coupled to the display housing  602   e  without a separate cover (e.g., without a cover glass). The display stack  624   e  may include various components arranged in a stack or laminate, including, for example, a back polarizer  626   e , a bottom glass  628   e , a top glass  630   e , and a front polarizer  632   e . These are merely exemplary components or layers of the display stack  624   e , and more, fewer, or different components may be included in the display stack  624   e , including a backlight, illumination panel(s), light guide panel(s), organic light emitting diodes, liquid crystal layers, or the like. 
     The display stack  624   e  may be attached to the display housing  602   e  via a joining member  606   e . The display stack  624   e  may extend substantially to the edge of the display housing  602   e , except that an edge trim  608   e  may be disposed on and/or attached to an edge  622  of the display stack  624   e . The edge trim  608   e  may cover the edge  622  of the display stack  624   e  and the joining member  606   e , and may protect these components from damage. The edge trim  608   e  may also prevent light from entering or leaving the display stack  624   e  through the edge  622 . Furthermore, the edge trim  608   e  may cover the ends or peripheral sides of the layers of the display stack  624   e  (e.g., bottom glass  628   e , top glass  630   e , and front polarizer  632   e ). This may improve the appearance of the display portion  600   e  (by covering unsightly seams) and may help prevent delamination or other damage to the multiple layers of the display stack  624   e . The edge trim  608   e  may be similar in structure, material, function, etc. to, and may be formed or finished in the same way as, the edge trim  430  and  608   b  discussed above. 
       FIG. 6F  depicts a partial cross-sectional view of a display portion  600   f  in which a display stack  624   f  is coupled to a display housing  602   f . The display stack  624   f  is attached to the display housing  602   f  via a joining member  606   f . The display stack  624   f  may be similar in structure, material, function, etc., to the display stack  624   e  discussed above. For example, the display stack  624   f  may include a back polarizer  626   f , a bottom glass  628   f , a top glass  630   f , and a front polarizer  632   f.    
     As shown in  FIG. 6F , and similar to the display housing  602   c  in  FIG. 6C , the display stack  624   f  may be set into the display housing  602   f . In some cases, an exterior surface of the display stack  624   f  may be substantially flush with an edge  614   f  of the display housing  602   f , and the edge  614   f  (and optionally the joining member  606   f ) may define a bezel or frame that surrounds or frames at least part of the display stack  624   f . Moreover, the part of the display housing  602   f  that surrounds the edges of the display stack  624   f  may protect the edges of the display stack  624   f  from delamination, chips, breaks, contaminants, or other potential damage. 
       FIG. 6G  depicts a partial cross-sectional view of a display portion  600   g  in which a display stack  624   g  is coupled to a display housing  602   g . The display stack  624   g  may be similar in structure, material, function, etc., to the display stack  624   e  discussed above. For example, the display stack  624   g  may include a back polarizer  626   g , a bottom glass  628   g , a top glass  630   g , and a front polarizer  632   g.    
     The display stack  624   g  is attached to the display housing  602   g  via a joining member  606   g . The display housing  602   g  includes a notched region that defines a shelf  616   g  to which the display stack  624   g  is attached (via the joining member  606   g ). This configuration allows the display stack  624   g  to be at least partially surrounded or framed (around its outer edge) by an edge  618   g  of the display housing  602   g , similar to the configuration in the display portion  600   d  ( FIG. 6D ). 
       FIG. 6H  depicts a partial cross-sectional view of a display portion  600   h  in which a display  634  is coupled to a display housing  602   h  (which may be similar to other display housings described herein). The display  634  may be an organic light emitting diode (OLED) display, or any other suitable display or display stack, and may include a cover (e.g., a glass, sapphire, or plastic protective cover) and/or other suitable components. 
     The display  634  is attached to the display housing  602   h  via any suitable attachment technique. Space between the display  634  and an interior surface of the display housing  602   h  may be filled with a potting material  635  (which may be similar to the potting material  211  described above, and may include polyurethane, silicone, epoxy, or any other suitable potting material). The potting material  635  may support the display  634  and the display housing  602   h . The potting material  635  may be any suitable material, such as silicone, epoxy, polyurethane, aerogel, or any other suitable polymer or other material.  FIG. 6H  shows the potting material  635  occupying all of the otherwise empty space between the display  634  and the display housing  602   h . In other examples, the potting material  635  may occupy less than all of the otherwise empty space. The potting material  635  may also adhere, bond, or otherwise retain the display  634  to the display housing  602   h . In some cases, the potting material  635  may be the exclusive mechanical attachment between the display  634  and the display housing  602   h.    
       FIG. 6J  depicts a partial cross-sectional view of a display portion  600   j  in which a display  638  is coupled to a display housing  602   j  (which may be similar to other display housings described herein). The display  638  may be an organic light emitting diode (OLED) display, or any other suitable display or display stack, and may include a cover (e.g., a glass, sapphire, or plastic protective cover) and/or other suitable components. 
     The display  638  may be attached to the display housing  602   j  via an adhesive  636 . The adhesive  636  may retain the display  638  to the display housing  602   j . In some cases, the display  638  and the adhesive  636  add structural strength and rigidity to the display housing  602   j , allowing for a thinner display housing  602   j  to be used, relative to display portions that do not have a display  638  adhered directly to the display housing  602   j . In some cases, a large area of a back of the display  638  (e.g., about 50%, about 60%, about 75%, about 85%, about 90%) may be adhered to the display housing  602   j , which may increase rigidity of the overall structure as compared to a joining technique where the display  638  is attached to the display housing  602   j  at the periphery of the display. 
       FIGS. 7A-7B  depict partial cross-sectional views of computing devices having various combinations of the base portions and display portions described above, viewed along sections B-B and C-C in  FIG. 1A .  FIGS. 7A-7B  depict the computing device in a closed configuration, rather than the open configuration shown in  FIG. 1A . 
       FIG. 7A  depicts a partial cross-sectional view of a computing device  700   a  that includes a display portion  701   a  and a base portion  703   a . The display portion  701   a  includes a cover  706   a  attached to a display housing  702   a  via a joining member  712   a , and a display stack  718  within the display housing  702   a . The display portion  701   a  is similar to the display portion  600   a  ( FIG. 6A ), and the materials, structure, and function of the display portion  701   a  (or the components thereof) may be the same as or similar to those of the display portion  600   a.    
     The computing device  700   a  also includes a base portion  703   a  that includes a top case  708   a  coupled to a bottom case  704   a  via a joining member  710   a . The base portion  703   a  is similar to the base portion  400   a  ( FIG. 4A ), and the materials, structure, and function of the base portion  703   a  (or the components thereof) may be the same as or similar to those of the base portion  400   a.    
     The cover  706   a  of the display portion  701   a  and the top case  708   a  of the base portion  703   a  may both be formed from the same or similar material, and may be coupled to the display housing  702   a  and the bottom case  704   a , respectively, in similar ways. Accordingly, the side of the computing device  700   a  may have a consistent and uniform appearance. For example, the common materials and physical integration between the display portion  701   a  and the base portion  703   a  provide a substantially symmetric structure (although the exact thicknesses and sizes of the components may vary between the display portion  701   a  and the base portion  703   a ). Moreover, where the top case  708   a  and the cover  706   a  are formed from the same material, the edges of those components may be similar or identical in appearance (e.g., color, texture, surface polish, etc.). 
     The components shown in  FIG. 7A  may be subjected to the same finishing process. For example, the edge of the top case  708   a  and the edge of the cover  706   a  may be subjected to the same polishing process and/or may be polished to the same or similar degree of polish (or surface roughness). Further, as noted above, the joining members  710   a  and  712   a  may be co-finished along with the top case  708   a  and the cover  706   a  so that all of these components have the same or a similar appearance, surface finish, etc. 
       FIG. 7B  depicts a partial cross-sectional view of a computing device  700   b  that includes a display portion  701   b  and a base portion  703   b . The display portion  701   b  includes a display stack  720  attached to a display housing  702   b  via a joining member  712   b . The display portion  701   b  is similar to the display portion  600   a  ( FIG. 6A ), and the materials, structure, and function of the display portion  701   b  (or the components thereof) may be the same as or similar to those of the display portion  600   a . The display stack  720  may be the same as or similar to the display stack  624   e  ( FIG. 6E ), and may include, for example, a back polarizer, a bottom glass, a top glass, and a front polarizer. These are merely exemplary components or layers of the display stack  720 , and more, fewer, or different components may be included in the display stack  720 . In some cases, the display portion  701   b  does not include a separate cover in front of or covering the display stack  720 . In such cases, the front-most layer of the display stack  720  may define the user interface surface (e.g., the external surface) of the display portion  701 . 
     The computing device  700   b  also includes a base portion  703   b  that includes a top case  708   b  coupled to a bottom case  704   b  via a joining member  710   b . The base portion  703   b  is similar to the base portion  400   a  ( FIG. 4A ), and the materials, structure, and function of the base portion  703   b  (or the components thereof) may be the same as or similar to those of the base portion  400 . 
     The display portion  701   b  and the base portion  703   b  also include edge trims  714 ,  716  (respectively) disposed on and/or attached to the edges of the display stack  720  and the top case  708   b . The materials, structure, and function of the edge trims  714 ,  716  may be the same as or similar to those of the edge trim  430 . The edge trims  714 ,  716  may protect the display stack  720  and the top case  708   b , for example, by preventing or reducing chipping, cracking, or other damage to the edge of the display stack  720  and the top case  708   b . Further, where the display stack  720  and/or the top case  708   b  include multiple layers, the edge trims  714 ,  716  may help to prevent delamination of (as well as hide) those layers. 
     The edge trims  714 ,  716  may have a same or similar appearance (including color, surface polish, etc.) to each other and/or to other parts of the computing device  700   b . For example, the edge trims  714 ,  716  may be formed from or include the same materials as the joining members  710   b ,  712   b , such that the edge trims  714 ,  716  and the joining members  710   b ,  712   b  have substantially the same appearance (e.g., color, surface finish, etc.) to one another, furthering the uniformity and consistency of the sides of the computing device  700   b.    
     As noted above, a top case for a computing device may be formed from a single, continuous sheet of material, such as glass or ceramic. Where a top case has a relatively large surface area as compared to its thickness, as might be seen in a top case for a notebook computer, reinforcements may be added to or otherwise incorporated with the top case to increase the stiffness, strength, toughness, or other property of the top case (and/or a computing device as a whole). For example, reinforcements may increase the torsional stiffness of the top case, which may in turn increase the torsional stiffness of the computing device as a whole. Such reinforcements may also define regions of higher stiffness and regions of lower stiffness to define input regions having different structural properties, as described herein. 
       FIG. 8A  is an exploded view of a top case  800   a  and a reinforcement frame  802   a  that may be applied to the top case  800   a . As noted above, a top case  800   a  may define an input surface of an integrated interface system that receives various types of inputs, such as touch and force inputs. Moreover, the integrated interface system may include touch sensors, force sensors, displays, haptic actuators, and the like, that may be attached to or otherwise integrated with the top case  800   a . The top case  800   a  with the reinforcement frame  802   a  may help define a structural platform for the components integrated interface system, as well as providing an input surface for the integrated interface system. Further, as described herein, reinforcements such as the reinforcement frame  802   a  may help define input regions or define the physical or mechanical response of the top case  800   a  to various types of inputs. 
     The top case  800   a  may be similar in structure, material, function, etc., to the top case  112  discussed above. For example, the top case  800   a  may be formed from or include glass, polycarbonate, ceramic, or any other suitable material. In some cases, the top case  800   a  is a single glass member (e.g., a sheet of glass). The top case  800   a  may have no seams, holes, or other openings in a top surface of the top case  800   a.    
     The reinforcement frame  802   a  may be formed from or include any suitable material, such as glass, plastic, carbon fiber, metal, or the like. The reinforcement frame  802   a  may have any suitable shape. As shown, the reinforcement frame  802   a  defines a first frame region  804   a  and a second frame region  806   a . The first frame region  804   a  may be under a keyboard region  808  of the top case  800   a . The keyboard region  808 , shown here as a recessed portion (which may be rectangular or any other suitable shape) formed in the top case  800   a , may be configured to have keys or key mechanisms disposed therein. In other implementations, such as where a virtual keyboard is implemented, the keyboard region  808  may not be defined by or use a recessed portion in the top case  800   a . Nevertheless, the reinforcement frame  802   a  may be used despite the frame not surrounding or corresponding to a recessed portion of the top case  800   a.    
     The reinforcement frame  802   a  also defines a second frame region  806   a , which may be under a palm rest region  810   a . The palm rest region  810   a  may correspond to a region where hands are typically rested when interacting with a notebook computer, and may be part of or define part of a touch-input region of the top case  800   a . The palm rest region  810   a  may include a trackpad region that is differentiated from other portions of the top case  800   a . The trackpad region may be a region that receives touch and/or force inputs, such as inputs for cursor control, gesture inputs, multi-touch inputs, and the like. For example, the trackpad region may be defined by a border on the top case  800   a , and the second frame region  806   a  may be positioned under the border. Alternatively, the entire top case  800   a  (e.g., both keyboard and non-keyboard regions of the top case  800   a ) may be a touch-input region. In such cases, the second frame region  806   a  may not correspond to any particular functional or physical borders on the top case  800   a . Rather, the second frame region  806   a  may generally reinforce the palm rest region  810   a . Nonetheless, the second frame region  806   a  may have the shape shown in  FIG. 8A . Other shapes and configurations for the reinforcement frame  802   a  are also contemplated. 
     The reinforcement frame  802   a  may also help to limit force or touch inputs that are applied to one region of the top case  800   a  (e.g., the keyboard region  808 ) from affecting the top case  800   a  in another region (e.g., the palm rest region  810   a ). For example, where a force is applied within the keyboard region  808  (as a result of a user striking a virtual or mechanical key within the keyboard region  808 ), the reinforcement frame  802   a  may prevent that force from resulting in a deflection or deformation of the top case  800   a  in the palm rest region  810   a  (or it may reduce the deflection or deformation as compared to a top case  800   a  without a reinforcement frame  802   a ). 
     The reinforcement frame  802   a  may be attached to the top case  800   a  in any suitable manner. For example, the reinforcement frame  802   a  may be glued or adhered to the top case  800   a  with an adhesive (e.g., an HSA, PSA, epoxy, cyanoacrylate, or the like). As another example, the reinforcement frame  802   a  may be fused to the top case  800   a  by a sintering and/or annealing process. More particularly, the reinforcement frame  802   a  may be disposed on the top case  800   a , and then the reinforcement frame  802   a  and top case  800   a  may be heated to a temperature and for a duration sufficient to cause the reinforcement frame  802   a  to fuse to the top case  800   a.    
       FIG. 8B  is an exploded view of a top case  800   b  and a reinforcement frame  802   b  that may be applied to the top case  800   b . The materials, structure, and function of the top case  800   b  and the reinforcement frame  802   b  may be the same as or similar to the top case  800   a  and the reinforcement frame  802   a  discussed above with respect to  FIG. 8A . However, as shown in  FIG. 8B , the top case  800   b  may include an opening  812  (e.g., a rectangular opening) instead of a recessed portion of the top case  800   a . The opening  812  may correspond to a keyboard region, and it may be configured to accommodate or receive a keyboard. For example, a keyboard that includes a plurality of key mechanisms (e.g., keycaps, keycap support mechanisms, key-make sensors or switches, or the like) coupled to a carrier plate (e.g., a circuit board or other substrate) may be positioned in the opening  812 . Where an opening in a top case is configured to at least partially receive and/or frame a keyboard, the opening may be referred to as a keyboard opening. In embodiments where a top case has a keyboard opening, the keyboard opening may be the only opening in the top surface of the top case, and the remaining portions of the top case may be continuous (e.g., have no additional openings, seams, gaps, discontinuities, or the like). 
       FIG. 9A  depicts an example top case  900  with a reinforcing rib structure  902  integrally formed with the top case  900 . The reinforcing rib structure  902  may perform the same or similar function as the reinforcement frame  802   a  in  FIG. 8A . As shown in  FIG. 9A , the rib structure  902  has a shape that is substantially similar to the reinforcement frame  802   a  in  FIG. 8A , with a first rib portion  906  under a keyboard region  904 , and a second rib portion  908  under a palm rest region. 
       FIG. 9B  depicts a partial cross-sectional view of the top case  900 , viewed along section D-D in  FIG. 9A .  FIG. 9B  depicts a portion of the reinforcing rib structure  902  that supports or reinforces the keyboard region  904 . As shown, the reinforcing rib structure  902  and the top case  900  form a monolithic structure. For example, the reinforcing rib structure  902  may be formed by machining, etching, ablating, or otherwise removing material from a single sheet of material (e.g., glass). As another example, the reinforcing rib structure  902  may be formed by a molding or slumping process in which the top case  900  is heated and conformed to a mold that defines the reinforcing rib structure  902  (as well as other features and/or shapes of the top case  900 , such as the keyboard region  904  or other areas of high or low relief). 
       FIG. 10  depicts an example top case  1000  with multiple reinforcing members  1002 ,  1004 ,  1006 , and  1008  attached to the bottom surface of the top case  1000 . For example, the reinforcing members  1002  are attached to an area of the top case  1000  that corresponds to a keyboard region  1001 . The reinforcing members  1002  may stiffen or otherwise reinforce the keyboard region  1001 . For example, the reinforcing members  1002  may help prevent or reduce deformation or deflection of the keyboard region  1001  as a result of typing inputs (either applied directly to the top case  1000  or to a key mechanism coupled to the top case  1000 ). As shown, the reinforcing members  1002  form an “x” shape, though other configurations and shapes are also possible. Also, while the keyboard region  1001  in  FIG. 10  is recessed relative to other parts of the top case  1000 , the reinforcing members shown and described in  FIG. 10  may be used with other top case configurations, such as substantially flat (e.g., planar) top cases that do not have a recessed keyboard region. 
     Other reinforcing members may be attached to other areas of the top case  1000 . For example, the reinforcing members  1004  are attached to the top case  1000  along the sides of the keyboard region  1001 , and the reinforcing member  1008  is attached to the top case  1000  along the top of the keyboard region  1001 . These reinforcing members may similarly provide added stiffness or strength to the top case  1000  (and to the computing device more generally), and may help isolate forces applied to one region of the top case  1000  (e.g., to the keyboard region  1001 ) from causing deformations or deflections in other regions of the top case. 
     The reinforcing members  1006  are coupled to the top case  1000  in a palm rest region  1003  that is below the keyboard region  1001 . The reinforcing members  1006  are positioned to leave a relatively large central region unreinforced. The unreinforced region may correspond to or define a trackpad or other touch or force sensitive input region that is configured to receive touch and/or force based inputs, such as gestures (e.g., swipes, pinches), multi-touch inputs, clicks, and the like. In some cases, a trackpad or other touch/force sensitive input region is configured to deform or deflect in response to certain inputs. These deflections or deformations may be used to determine an amount of force applied to the input region and to determine when a user input corresponds to a selection or a “click.” In such cases, leaving the input region substantially unreinforced may facilitate and permit the input region to deform sufficiently for the touch and/or force detection. Reinforcing members may also be included (or strategically omitted) to create haptic or tactile feedback regions, such as by isolating haptic outputs from a particular haptic actuator or device to a localized region that is less than the entire top case of a device. 
     As noted above, a glass (or other light-transmissive material) top case on a computing device, such as the top case  112 , may be used as a light guide or light pipe for illuminating portions of the top case, such as keys, a keyboard region, displays, and the like. More particularly, an integrated interface system that includes a glass or light-transmissive top case may illuminate portions of the top case to improve the visibility, readability, or otherwise produce a desired appearance for the integrated interface system.  FIGS. 11A-11E  show how a light source may be integrated with a computing device to illuminate a top case of an integrated interface system. 
       FIG. 11A  depicts an exploded view of a base portion  1100  of a computing device (e.g., a notebook computer) that includes a top case  1102   a  and a bottom case  1104 . The top case  1102   a  and the bottom case  1104  may be similar in structure, material, function, etc., to any of the top cases and bottom cases described herein. For example, the top case  1102   a  may be formed from or include a glass, ceramic, or other light-transmissive material. 
     The base portion  1100  also includes a light source  1106   a . The light source  1106   a  may include one or more individual lighting elements, such as LEDs, OLEDs, incandescent elements, fluorescent elements, or the like. The light source  1106   a  is configured as a light bar, and is positioned along a side of the base portion  1100  that is adjacent the bottom of a keyboard region  1103  on the top case  1102   a  (e.g., along a side of the base portion  1100  that is opposite the side that joins a display portion of the device). 
       FIG. 11B  depicts a partial cross-sectional view of the base portion  1100 , viewed along section E-E in  FIG. 11A . The light source  1106   a  is positioned in a recess  1108  formed into the edge of the top case  1102   a , though other locations are also possible. In particular, the light source  1106   a  may be positioned in any position such that light emitted from the light source  1106   a  is directed or coupled into the top case  1102   a  (e.g., into an edge of the top case  1102   a ). In some cases, the light source  1106   a  may be positioned away from the edge of the top case  1102   a , and light guides, light pipes, or other mechanisms may direct the light from the light source to the edge of the top case  1102   a.    
     By directing light into a top case, a light source may be used to illuminate various regions and/or components of a device.  FIG. 11C , for example, depicts an example computing device  1110  with a light source  1106   c . The computing device  1110  includes a top case  1102   c  and a display  1112 , which may be positioned to display buttons and/or other affordances on a top case  1102   c  in a region above a keyboard (e.g., between the keyboard and a display portion of the device). This region may be referred to as a virtual key region, and may replace or complement a conventional row of “function” keys on a conventional keyboard. Moreover, the virtual key region may be configured to present different keys, buttons, or affordances depending on an operational state of the device, such as the particular program that is being executed, what is being displayed on an associated display screen, or the like. For example, the affordances may be selected, from a group of candidate affordances, based on their relevance to and/or ability to control a user interface that is being displayed on a primary display of a device (e.g., the display  204 ). The display  1112  may include components such as liquid crystal layers (which may be coupled to the top case  1102   c ), and the light source  1106   c  may provide illumination for the display  1112 . As shown, the virtual key region includes multiple segments. These segments may correspond to a single underlying display, or multiple displays (e.g., a separate display for each segment). The display  1112  may represent a single display that spans multiple segments, or one display, of a group of displays, that corresponds to a single segment. 
     Because the display  1112  is positioned above a keyboard, the light source  1106   c  is positioned along the edge of the top case  1102   c  that is above the keyboard (e.g., proximate a display portion of a notebook computer). In some cases, the display  1112  may not require a separate back light, such as where the display  1112  is an OLED display. In such cases, the light source  1106   c  may be positioned elsewhere to illuminate other areas of the top case  1102   c , such as a keyboard region, which may include mechanical keys, virtual keys, or a combination of mechanical and virtual keys. 
       FIG. 11D  depicts an example computing device  1114  with a light source  1106   d  positioned as shown in  FIGS. 11A-11B . The computing device  1114  includes a top case  1102   d  and a keyboard region  1116 . The keyboard region  1116  may include or be associated with a display that displays virtual keys and/or other affordances, or it may include or be associated with a mechanical keyboard (e.g., key mechanisms coupled to the keyboard region  1116  of the top case  1102   d ). Where the keyboard region  1116  includes or is associated with a display, the light source  1106   d  may provide illumination for the display. Where the keyboard region  1116  includes or is associated with a mechanical keyboard, the light source  1106   d  may illuminate keycaps, portions of the top case that frame (or that are visible between) the keycaps, or other portions of the keyboard region  1116 . 
     In some cases, the keyboard region  1116  may include individual key regions that are not associated with traditional mechanical keys. For example, individual key regions may be defined by paint, etching, textures, masked regions, or other indicators disposed or formed on the top case  1102   d . As one specific example, individual key regions in the keyboard region  1116  may be defined by masked (e.g., substantially opaque) regions framed or otherwise visually distinguished by unmasked (e.g., transparent or translucent) regions. When illuminated by the light source  1106   d , light may pass through the unmasked regions (and/or unmasked glyphs or characters within the masked regions), thereby visually defining and distinguishing the keys. 
       FIG. 11E  depicts an example computing device  1118  with a light source  1106   e  positioned along a bottom side of the top case  1102   e . As shown, the top case includes a keyboard  1122 , which may be a mechanical keyboard or a virtual keyboard. Where the keyboard  1122  is a virtual keyboard, the computing device  1118  may include a display below the top case  1102   e  to produce images of the keys. The display may be configured to produce images of keys for a virtual key region  1120 , which may be above a keyboard (e.g., between the keyboard and a display portion of the device) and may be configured to present different keys in the virtual key region depending on an operational state of the device, as described above. The light source  1106   e  may be configured to provide illumination to the display to illuminate the keyboard  1122  and the virtual key region  1120 . Alternatively, in cases where the virtual key region  1120  is associated with its own display and light source (e.g., where the virtual key region  1120  includes an OLED display), the light source  1106   e  may be configured only to illuminate the keyboard  1122  or the display that produces the key images of the keyboard  1122 . 
     In some cases, keys, virtual key regions, trackpad regions, and/or other input regions (or other graphics, glyphs, symbols, or the like) may be shown by backlighting a masked surface with openings that define the keys, regions, and/or other graphics.  FIGS. 11F-11G  depict an example computing device  1130  in which various regions on a top case are defined by openings in an opaque mask, which are made visible by supplying light below the opaque mask. 
       FIGS. 11F-11G  depict an example computing device  1130  that includes a base portion  1131  coupled to a display portion  1133 . The base portion  1131  may include a bottom case  1137  and a top case  1139 . The top case  1139  and the bottom case  1137  may be similar in structure, material, function, etc., to any of the top cases and bottom cases described herein. The top case  1139  may be formed of a light-transmissive material, and may be associated with a patterned mask, as described herein. The computing device  1130  also includes a keyboard  1135 , which may be a mechanical keyboard, a display that produces images of keys, or, as described herein, a keyboard defined by openings in an opaque masking region. 
     The computing device  1130  also includes a first region  1138  above the keyboard  1135  and a second region  1140  below the keyboard  1135 . The first and second regions  1138 ,  1140  may be touch and/or force sensitive input regions, as described herein, and may be associated with a patterned mask that defines input region borders, glyphs, symbols, or the like. As shown in  FIG. 11F , the first and second regions  1138 ,  1140  are substantially featureless, corresponding to a mode in which no illumination is provided below a patterned mask that is associated with the top case  1139 .  FIG. 11G  shows the computing device  1130  with active illumination, revealing virtual input regions  1144  in the first region  1138  and a trackpad region  1142  in the second region  1140 . The virtual input regions  1144  and the trackpad region  1142  may be defined by openings (e.g., perforations or micro-perforations) in an opaque mask material associated with the top case  1139 , which are illuminated from below the mask. Light guides, light extraction features, or other optical components underlying or integrated with the top case  1139  may help couple light to the openings in the patterned mask to facilitate illumination of the patterns. 
     Because the mask and illumination are positioned below the top case  1139 , the virtual input regions  1144  and the trackpad region  1142  may be not visible when the illumination is inactive, thus allowing the first and second regions  1138 ,  1140  to be operative to receive touch and/or force inputs without any borders or boundaries. When the illumination is active, however, the additional input region definitions may correspond to different functionality. For example, when illumination is not present, substantially all of the second region  1140  may act as a touch and/or force sensitive track pad. When illumination is present, the device  1130  may respond differently to touch and/or force inputs applied within the trackpad region  1142  than inputs applied to portions of the second region  1140  outside the trackpad region  1142 . 
       FIG. 11H  is an exploded view of the base portion  1131  of  FIG. 11F . The base portion  1131  includes the top case  1139 , the bottom case  1137 , a mask layer  1152 , and a light guide  1158 . The base portion  1131  also includes a light source  1162  that is configured to direct light, when the base portion  1131  is assembled, into the light guide  1158 . 
     As noted above, the top case  1139  may be formed from a light-transmissive material, such as glass, plastic, ceramic, or the like. The mask layer  1152  may be an opaque or substantially opaque material, such as an ink, dye, polymer layer, or other material. The mask layer  1152  may have patterns  1154 ,  1156  defining the virtual input regions  1144  and the trackpad region  1142 , respectively. The patterns  1154 ,  1156  may be or may include a series of perforations or micro-perforations, or larger gaps in the mask material. The mask layer  1152  may be deposited on a bottom surface of the top case  1139  or a top surface of the light guide  1158 . For example, the mask layer  1152  may be an ink, dye, or adhesive sheet that may be bonded or otherwise applied to the light guide  1158  or the top case  1139 . In other cases, the mask layer is a separate component (e.g., an opaque polymer sheet) that may have at least some surfaces that are not bonded or adhered to the top case  1139  or the light guide  1158 . 
     The light guide  1158  may be a light-transmissive material that receives light from the light source  1162  and directs the light toward the patterns  1154 ,  1156  of the mask layer  1152 . The light guide  1158  is shown having substantially a same area as the mask layer  1152  and top case  1139 . In some cases, the light guide  1158  may be configured and shaped to direct light substantially only to the patterns  1154 ,  1156  of the mask layer  1152 . 
     As shown, the mask layer  1152  includes patterns  1154 ,  1156  that correspond to the virtual input regions  1144  and the trackpad region  1142 . In other cases, it may define additional or other input regions, graphics, keys (e.g., all or some of the keys of the keyboard  1135 ), symbols, or the like. Further, while a single light guide  1158  and a single light source  1162  are shown, multiple light guides and/or light sources may be implemented to allow for selective illumination of the illuminable features. For example, the virtual input regions  1144  may be illuminable separately from the trackpad region  1142  (e.g., one can be on while the other is off). Further, the mask layer  1152  may also include patterns that correspond to the keys of the keyboard, which also may be selectively illuminated. When the keys, trackpad region  1142 , and the virtual input regions  1144  are all unilluminated, the top case  1139  may have a substantially uniform appearance (e.g., it may appear to be a uniform glossy black surface). 
     As described above, key input functionality may be provided by an integrated interface system in various ways. For example, an integrated interface system may include or be configured to detect inputs from a keyboard having mechanical keys. Alternatively or additionally, an integrated interface system may include or be configured to detect inputs from a virtual keyboard displayed on a top case of the integrated interface system. More particularly, the integrated interface system may include a display that produces images of keys or other affordances on an otherwise featureless (e.g., flat) surface, such as the top case of an integrated interface system. A virtual keyboard may also or instead include static key regions (e.g., defined by paint, masks, or other visual indicia) on a featureless surface of a top case. Also, various combinations of these types of keyboards may be used in a single integrated interface system. For example, one portion of a keyboard for an integrated interface system may include mechanical keys, while another portion may include a virtual keyboard (or one or more virtual keys, buttons, or other affordances). 
     Top cases of integrated interface systems as described herein, such as continuous top cases formed of glass or ceramic materials, may be configured to accommodate any one or any combination of these types of keyboards. For example,  FIGS. 12A-15B  relate to example computing devices that include integrated interface systems with both mechanical keys and virtual keys, while  FIGS. 16A-17B  relate to example computing devices that include integrated interface systems with only virtual keys. As another example, an integrated interface system may include only mechanical keys. 
       FIG. 12A  depicts an example computing device  1200  that includes a base portion  1201  coupled to a display portion  1203 . The base portion  1201  may include a bottom case  1204  and a top case  1202 . The top case  1202  and the bottom case  1204  may be similar in structure, material, function, etc., to any of the top cases and bottom cases described herein. The computing device  1200  also includes a mechanical keyboard  1205  and a virtual key region  1208 . (The virtual key region  1208  may be omitted and/or replaced with additional mechanical keys, such as with a row of mechanical “function row” keys.) The computing device  1200  may also include a conventional trackpad  1207 , or it may omit the trackpad  1207 . In the latter case, a trackpad region may encompass larger areas of the base portion  1201  than the trackpad  1207 , including substantially the entire area of the top case  1202  below the keyboard (e.g., the palm rest region), the areas along the lateral sides of the keyboard, and even the keyboard itself. 
     The keys of the mechanical keyboard  1205  (such as a representative key  1206 ) may include suitable mechanisms and components for receiving inputs, providing a tactile response and/or motion in response to the inputs, and for allowing the computing device  1200  to detect key actuations. The keys may be coupled to the top case  1202  in any suitable way, such as with adhesive, mechanical clips, fasteners, or the like. Example key mechanisms and attachment techniques are discussed herein. 
     The virtual key region  1208  (which may include multiple segments) may include or be associated with one or more displays that is positioned under the top case  1202  (e.g., within an interior volume of the base portion  1201 ). The virtual key region  1208  may also include or be associated with touch sensors that detect touch inputs applied to the virtual key region  1208 , as described herein. The virtual key region  1208  may dynamically display different buttons, keys, affordances, images, or the like, based on different operating modes of the device  1200 . For example, the virtual key region  1208  may display a first set of affordances (and optionally other information) when a user of the device  1200  is interacting with a first application, and a second set of affordances (and optionally other information) when the user is interacting with a second application. When an input, such as a touch or force input, is detected at a position on the virtual key region  1208 , the device  1200  will take a particular action based on the affordance that is displayed on that position at the time the input was detected. Thus, if the virtual key region  1208  is displaying function keys (e.g., F1-F12 keys), an input on a particular function key may cause the device  1200  to take actions associated with that particular function key. If the virtual key region  1208  is displaying a slider for controlling a volume of the device  1200 , an input on the slider (e.g., a swipe or gesture input) may result in the device  1200  adjusting its output volume. 
     The top surface of the top case  1202  may be substantially flat (e.g., planar). In particular, the top case  1202  may be substantially featureless, lacking substantial recesses, openings, or areas of high and/or low relief. For example, the top case  1202  may be a substantially smooth, planar sheet of glass or ceramic. In such cases, the keys of the mechanical keyboard  1205  may extend above the top surface of the top case  1202 , which may interfere with the display portion  1203  when the computing device  1200  is in a closed configuration. In such cases, the top case  1202  (e.g., the entire top case) may be recessed relative to a rim or edge of the bottom case  1204 , such that a gap exists between the top case  1202  and the display portion  1203  when the device  1200  is closed. The mechanical keyboard  1205  may have a size or height to fit inside the gap without contacting the display portion  1203 . 
     Where a transparent glass or ceramic (or other material) is used, the top case  1202  may be suited for use with keyboards that have both mechanical keys and virtual keys, as the transparency allows the top case  1202  to act as a cover (and input surface) for a display of a virtual keyboard. 
       FIG. 12B  is an exploded view of the base portion  1201  of  FIG. 12A . The base portion  1201  shows the mechanical keyboard  1205 , the top case  1202 , the bottom case  1204 , and a touch and/or force sensor  1210  below the top case  1202 . The touch and/or force sensor  1210  may be disposed within an interior volume defined by the top case  1202  and the bottom case  1204 . 
     The keyboard  1205  may comprise multiple discrete keys and/or key mechanisms, or it may be a pre-assembled structure that includes the keys held captive to a base plate or otherwise coupled together. The discrete keys or the pre-assembled key structure may be coupled directly to a top surface of the top case  1202 , as described herein. 
     The touch and/or force sensor  1210  may include various touch and/or force sensing components, such as capacitive sensing elements, resistive sensing elements, or the like. The touch and/or force sensor  1210  may be configured to sense inputs applied to the top case  1202 , and may sense selections of keys of the keyboard  1205 , selections of affordances on the virtual key region  1208  ( FIG. 12A ), and/or touch inputs (e.g., clicks, taps, gestures, multi-touch inputs) applied to other areas of the top case  1202 . The touch and/or force sensor  1210  may be configured to detect inputs without regard to a force component, such as detecting only a location of one or more touch inputs. The touch and/or force sensor  1210  may also or instead be configured to detect a force component of one or more touch inputs, such as by determining an amount of deflection of the top case  1202  caused by a touch input. For simplicity, the touch and/or force sensor  1210 , as well as the touch and/or force sensors  1310 ,  1311 ,  1321 ,  1347 ,  1372 ,  1410 , and  1510 , are referred to herein simply as touch sensors. It will be understood that these sensors may provide touch input functionality, force input functionality, or both. 
     With respect to detecting selections of mechanical keys, the top case  1202  may be a continuous sheet of material, and as such may lack openings or holes allowing the keys to mechanically couple to components within the base portion  1201 . As a result, it may not be possible to use traditional key mechanisms for detecting key presses, because there is no direct access to the electronic components of the device  1200  through the top case  1202 . Accordingly, the touch and/or force sensor  1210  may use the same sensing technology (e.g., capacitive sensing) that is used to detect touch inputs in non-keyboard regions (e.g., a trackpad region) to determine when a key has been selected. Where the top case  1202  is glass or ceramic or another dielectric material, the dielectric properties of the top case  1202  may permit the touch and/or force sensor  1210  to detect the presence and/or location of fingers on the keyboard  1205  as well as the non-keyboard regions of the base portion  1201 . 
     The touch sensor  1210  may be substantially planar, or may include a substantially planar assembly, that is adjacent (or otherwise proximate) the top case  1202 . The planar shape of the touch sensor  1210  may complement the planar surface of the top case  1202 . In cases where the top case  1202  has ribs, frames, or other reinforcements on the interior-facing surface of the top case  1202 , the touch sensor  1210  may have openings, discontinuities, recesses, or other features that accommodate the reinforcements while allowing substantially planar portions of the touch sensor  1210  to be adjacent corresponding planar portions of the top case  1202 . 
       FIG. 13A  depicts an example computing device  1300  that includes a base portion  1301  coupled to a display portion  1303 . The base portion  1301  may include a bottom case  1304  and a top case  1302 . The top case  1302  and the bottom case  1304  may be similar in structure, material, function, etc., to any of the top cases and bottom cases described herein. The computing device  1300  also includes a mechanical keyboard  1305  and a virtual key region  1308 , which may be similar in structure, material, function, etc., to the keyboard  1205  and the virtual key region  1208  discussed above. Like the top case  1202 , the top case  1302  may be a continuous member (e.g., lacking any openings or holes in the top surface). 
     The top surface of the top case  1302  may define a recessed region  1307  in which the keyboard  1305  may be positioned. The recessed region  1307  may have any suitable depth. For example, the recessed region  1307  may be between about 0.5 mm and 5.0 mm deep. In some cases, the recessed region  1307  has a depth that results in the tops of the keycaps of the keyboard  1305  being substantially flush with or set slightly below non-recessed or surrounding areas of the keyboard. In such cases, the keycaps may not contact the display portion  1303  when the display portion  1303  is in a closed position relative to the base portion  1301  (e.g., when the device  1300  is closed). 
     The recessed region  1307  may have any suitable dimensions. As shown in  FIGS. 13A-13B , the recessed region  1307  defines an area that is only slightly larger than the keyboard  1305 . However, the recessed region  1307  may be larger. For example, the recessed region  1307  may provide more clearance (e.g., a larger gap) between the keyboard  1305  and the surrounding non-recessed regions of the top case  1302  (e.g., along the outer perimeter of the keyboard  1305 ). Moreover, the recessed region  1307  may be deeper or shallower than is shown. The recessed region  1307  is also shown as defining a substantially planar recessed surface. The surfaces of other recessed regions may not be planar, and may define additional recesses, protrusions, features, or the like. 
       FIG. 13B  is an exploded view of the base portion  1301  of  FIG. 13A . The base portion  1301  shows the keyboard  1305 , the top case  1302 , the bottom case  1304 , and a touch sensor  1310  below the top case  1302  (e.g., disposed within the interior volume defined by the top case  1302  and the bottom case  1304 ). The touch sensor  1310  may be similar in structure, material, function, etc., to the touch sensor  1210  discussed above. The keyboard  1305  may include key mechanisms that are coupled directly to the top case  1302 , or it may be a keyboard assembly such as the keyboard assembly  1314  described with respect to  FIG. 13C . A force sensing system may also be integrated with the base portion to facilitate detection of key presses, clicks, or the like, applied to the keyboard and/or non-keyboard regions of the base portion 
     The top case  1302  may be formed in any suitable manner to produce the recess  1307 . For example, if the top case  1302  is glass, it may be slumped over a mold that has a shape corresponding to the desired shape of the top case  1302 . More particularly, a sheet of glass may be heated and then placed in contact with a mold, and the glass may be conformed to the shape of the mold. Pressure may or may not be applied to the glass sheet during the slumping or molding process. Other forming processes may also be used, such as grinding, lapping, machining, blowing, etching, sintering, or the like. 
     The touch sensor  1310  may define a recessed region  1312  that substantially corresponds to and/or conforms to the recessed region  1307  in the top case  1302 . Accordingly, the touch sensor  1310  may conform to the shape of the top case  1302 , allowing the touch sensor  1310  to be in close proximity with (e.g., in direct contact with) an underside of the top case  1302 . By maintaining the surfaces of the touch sensor  1310  in close proximity with both the keyboard and the non-keyboard regions of the top case  1302 , touch and/or force sensing can be provided across substantially all of the top case  1302 . More particularly, the touch sensor  1310  can detect inputs in the keyboard region (e.g., key presses, gestures on or over the keys, etc.) as well as outside the keyboard region (e.g., clicks, taps, gestures, and other touch inputs applied to a palm rest region or any other touch or force sensitive region). A force sensing system may also be integrated with the base portion  1301  to facilitate detection of key presses, clicks, or the like, applied to the keyboard and/or non-keyboard regions of the base portion. 
       FIG. 13C  is an exploded view of a base portion  1313 , which may be an embodiment of the base portion  1301  of  FIG. 13A , in which a keyboard assembly  1314  is positioned in or accessible through an opening  1315  (e.g., a keyboard opening) in a top case  1316 . The top case  1316  may be similar to the top case  1302 , except that instead of the recess  1307 , the opening  1315  is formed in the top case  1316  to accommodate and allow access to the keyboard assembly  1314 . The base portion  1313  also includes the bottom case  1304  and a touch sensor  1311  below the top case  1316  (e.g., disposed within the interior volume defined by the top case  1316  and the bottom case  1304 ). The touch sensor  1311  may be similar in structure, material, function, etc., to the touch sensor  1310  discussed above. Moreover, the touch sensor  1311  may include a recess  1317  to accommodate the keyboard assembly  1314 . Alternatively, the touch sensor  1311  may omit the recess  1317  (e.g., it may be substantially flat or planar). The touch sensor  1311  may detect touch and/or force inputs applied anywhere to the top case  1316 , including touch inputs applied to the keyboard assembly  1314  and actuations of the keys of the keyboard assembly  1314 . A force sensing system may also be integrated with the base portion to facilitate detection of key presses, clicks, or the like, applied to the keyboard and/or non-keyboard regions of the base portion. 
     The keyboard assembly  1314  may include key mechanisms  1319 , which may include keycap support mechanisms, domes, switches, scissor mechanisms, biasing mechanisms, springs, butterfly hinges, and/or other suitable components. The key mechanisms  1319  may provide electrical and/or mechanical functionality (e.g., a tactile, moving key mechanism) for the keys of the keyboard assembly  1314 . The keyboard assembly  1314  may also include a base plate  1320  to which the key mechanisms  1319  may be coupled and an optional key web  1322  that defines key openings that frame the keys. The key web  1322  may also help prevent debris from entering the base portion  1313  from the keyboard. The keyboard assembly  1314  may also include a cover  1323  positioned over the key mechanisms  1319 . The cover  1323  may be a flexible sheet, layer, or membrane, and may be formed of or include plastic, a fabric, or the like. Where the cover is a fabric cover, the fabric may be organic materials, synthetic materials, woven materials, knit materials, composite materials, coated fabrics, sealed fabrics, watertight fabrics, multi-layer fabrics, or the like. 
     The cover  1323  may be attached to the base plate  1320  and/or the key mechanisms  1319 . The cover  1323  may substantially seal the keyboard assembly  1314  from the ingress of liquids, debris, or other contaminants. The cover  1323  may be sufficiently flexible to allow the key mechanisms  1319  to travel in response to actuation of a corresponding key. For example, the material of the cover  1323  may be sufficiently flexible, or an otherwise substantially inflexible material may include seams, folds, channels, crenellations, or other features or configurations that allow the key mechanisms  1319  to travel in response to an actuation of a key. 
     The keyboard assembly  1314  may further include keycaps  1318  that are positioned in key openings in the key web  1322  and coupled to the cover  1323 . The keycaps  1318  may be adhered to the cover  1323  directly over corresponding key mechanisms  1319 . For example, a key mechanism  1319  may include or define a keycap support that is movably supported relative to the base plate  1320  by a support mechanism (e.g., a butterfly hinge, scissor mechanism). The cover  1323  may overlie the keycap support (and may be adhered or otherwise affixed to the keycap support). A keycap may be affixed to the portion of the cover  1323  that overlies the keycap support. For example, the keycap may be affixed to the cover  1323  using ultrasonic welding, adhesive, mechanical engaging features, or the like. Accordingly, the cover  1323  may be sandwiched between the keycap support and the keycap. By adhering, bonding, or otherwise attaching the cover  1323  to the keycap supports and the keycaps, a substantially continuous, unbroken cover  1323  may be used, thereby maintaining the sealing function of the cover  1323  while still allowing a mechanical coupling between the key mechanisms  1319  and the keycaps  1318 . 
     The cover  1323  may have openings therethrough to allow a mechanical engagement between the keycap supports and the keycaps. In such cases, the openings may be smaller than the keycaps and the keycap supports, such that the keycaps and keycap supports cover and/or seal the openings. Accordingly, the exposed areas of the cover  1323  (e.g., the areas between the keycaps) may be substantially continuous and/or unbroken, thereby sealing the keyboard and preventing or limiting ingress of liquids, debris, or other contaminants into the key mechanisms and/or the base portion  1313 . 
     The base plate  1320  may be a circuit board with electrical interconnects that couple the keyboard assembly  1314  to components of the device such as a processor, memory, input interfaces, and the like. The electrical interconnects may allow electrical signals from the key mechanisms  1319  to be detected by the device to register key inputs. In cases where the touch sensor  1311  detects key presses or actuations, the key mechanisms  1319  may not include switches or other make-sensing components, and the base plate  1320  may not include electrical interconnects. In such cases, the key mechanisms  1319 , the base plate  1320 , and, optionally, the key web  1322  may be formed from or include dielectric or nonconductive materials such that fingers or other objects can be sensed by the touch sensor  1311  through the keyboard assembly  1314 . 
       FIG. 13D  is an exploded view of a base portion  1329 , similar to the base portions  1301 ,  1313 , showing another example arrangement of a keyboard assembly  1333  (which may otherwise be similar to or include similar components to the keyboard assembly  1314 ). In particular, in the embodiment shown in  FIG. 13D , the optional key web  1322  may be positioned below the cover  1323 . Also,  FIG. 13D  shows an embodiment where the cover  1323  defines the interface or user-contact surfaces of the keys (e.g., each key includes an underlying key mechanism but does not include an additional keycap on top of the cover  1323 ). In other cases, additional keycaps (similar to the keycaps  1318  in  FIG. 13C ) may be coupled to the cover  1323  to define the interface or user-contact surfaces of the keys. In other aspects, the embodiment of the base portion  1329  in  FIG. 13D  may be the same as or similar to the base portion  1313  of  FIG. 13C . For example, the base portion  1329  shown in  FIG. 13D  may include the bottom case  1304 , a touch sensor  1321  (which may be the same as or similar to the touch sensors  1310 ,  1311 ), and key mechanisms  1341  (which may be similar to the key mechanisms  1319 , but may include additional keycaps or other upper components due to the lack of separate keycaps in the keyboard assembly  1333 ). 
     In  FIGS. 13C-13D , a portion of the cover  1323  may be captured between two components of the keyboard assemblies  1314 ,  1333  or the device more generally. For example, in some cases, the cover  1323  has a keyboard region  1330  that covers the keys of the keyboard assembly, and an outer region  1332  that frames and/or surrounds the keyboard region  1330 . The outer region  1332  may extend sufficiently beyond the keyboard region  1330  such that at least a portion of the outer region  1332  is positioned and captured between an overlying component and an underlying component. In some cases, the overlying component is the top case  1316 . The underlying component may be any component of the keyboard assembly  1314 ,  1333  or the device with which the keyboard assembly is integrated. For example, the underlying component may be a key web (e.g., the key web  1322 ), a keyboard substrate (e.g., the base plate  1320 ), a circuit board, a support substrate or layer that provides structural and/or other support to the top case  1316 , a portion of the bottom case  1304 , a frame that is coupled to the bottom case  1304 , or the like. As a specific example, with reference to  FIG. 13D , the optional key web  1322  may be omitted and the outer region  1332  of the cover  1323  may be captured between a portion of the top case  1316  and a portion of the base plate  1320 . 
     Capturing the outer region  1332  of the cover  1323  between the top case  1316  and an underlying component may help to secure the cover  1323  to the device, may help seal the keyboard assembly, and may prevent the cover  1323  from shifting or sliding during use. In some cases, the captured outer region  1332  of the cover  1323  may be adhered or otherwise bonded to the top case and/or the underlying component where the cover  1323  is captured. 
       FIG. 13E  is an exploded view of a base portion  1334 , which may be an embodiment of the base portion  1301  of  FIG. 13A , showing an alternative arrangement of the components of a keyboard assembly  1335  (which may otherwise be similar to or include similar components to the keyboard assembly  1314 ). In particular, in the embodiment shown in  FIG. 13E  a cover  1336  (e.g., a fabric cover as described above) is positioned below keycaps  1337 , and a membrane  1338  is positioned below the cover  1336 . In the arrangement shown in  FIG. 13E , there is no rigid key web or other component that has exposed members between adjacent keycaps. Rather, the space between adjacent keycaps is open such that the cover  1336  is visible and/or exposed between the keycaps  1337 . 
     With reference to  FIG. 13E , the illustrated embodiment of the keyboard assembly  1314  includes the top case  1316  that defines the opening  1315 . The keyboard assembly  1314  may be positioned in the opening  1315  when the base portion  1313  is assembled. The keyboard assembly  1314  also includes keycaps  1337  (which may be similar to the keycaps  1318 ) that define exposed input surfaces of the keys. The cover  1336  may be positioned below the keycaps  1337 , and may define openings  1339 . The keycaps  1337  may be configured to mechanically couple to key mechanisms  1340  (which may be the same as or similar to the key mechanisms  1319 ,  1341  described above) that are positioned below the cover  1336  and are coupled to the base plate  1344  (which may be the same as or similar to the base plate  1320 ). For example, the key mechanisms  1340  may include support mechanisms (e.g., springs, butterfly hinges, scissor mechanisms) that mechanically couple to the keycaps  1337  to allow the keycaps  1337  to move and be actuated by a user. The key mechanisms  1340  may also include key-make sensing components, such as dome switches, capacitive or other sensors, or the like. The openings  1339  in the cover  1336  allow the keycaps  1337  to directly contact, mate with, and/or mechanically engage the key mechanisms  1340 . In other examples, the openings  1339  are omitted and the keycaps  1337  may be secured directly to the top of the cover  1336 , and the key mechanisms  1340  (or portions thereof) may be secured to the bottom of the cover  1336  or another component that is below the cover  1336 . 
     The keyboard assembly in  FIG. 13E  also includes a membrane  1338  positioned below cover  1336 . The membrane  1338  may also define openings  1342  through which the keycaps  1337  may engage with the key mechanisms  1340 . The membrane  1338  may be configured to help support the cover  1336  (e.g., to prevent the cover  1336  from sagging or drooping). The membrane  1338  may also help prevent debris from entering sensitive areas of the key mechanisms  1340  or other areas of the device. The membrane  1338  may be formed from any suitable material, such as silicone, polyurethane, polyisoprene, or any other suitable material. 
     The cover  1336  and the membrane  1338  may be secured to the keycaps  1337  (e.g., adhered, fused, etc.), or they may be detached from the keycaps  1337 . Various different example arrangements between the cover  1336 , the membrane  1338 , and the keycaps  1337  are described in greater detail with reference to  FIGS. 13F-13H and 13J-13K . Also, because at least parts of the cover  1336  and the membrane  1338  are below the keycaps  1337 , the cover  1336  and the membrane  1338  may be configured to deform, deflect, stretch, or otherwise allow the keycaps  1337  to move when actuated. 
     A support  1343  may be positioned below the membrane  1338  to maintain the membrane  1338  in a desired location, and may also provide structural support and/or increase the rigidity of the keyboard assembly. The support  1343  may be positioned on the base plate  1344  (which may be the same as or similar to the base plate  1320 ), and may be formed of or include any suitable material, including polymer, metal, metal alloy, composite (e.g., carbon fiber composites, reinforced plastics), or the like. 
     The base portion  1313  shown in  FIG. 13E  also includes ribs  1345  in the bottom case  1346  (which may be an embodiment of the bottom case  1304 ). The ribs  1345  may provide structural support to the bottom case  1346  and may generally increase the strength and/or stiffness of the base portion  1313  relative to a bottom case without the ribs. The ribs  1345  may be separate components that are attached to the bottom case  1346 , or they may be integrally formed with the bottom case  1346  (e.g., the bottom case  1346  may be molded, machined, cast, forged, or otherwise formed to have the ribs  1345  formed from the same piece of material as the rest of the bottom case  1346 . The ribs  1345  may also structurally support the keyboard assembly  1335  by contacting or otherwise being structurally engaged with the base plate  1344 . This arrangement may increase the strength and/or stiffness of the keyboard assembly  1335 . The ribs  1345  may also contact the underside of the top case  1316  (or otherwise support the top case  1316  through interstitial layers or components such as a touch sensor layer) to increase the strength and/or stiffness of the top case  1316 . The keyboard assembly  1335  may also include a touch sensor  1347  (which may be the same as or similar to the touch sensors  1310 ,  1311 , described above). A force sensing system may also be integrated with the base portion  1313  to facilitate detection of key presses, clicks, or the like, applied to the keyboard and/or non-keyboard regions of the base portion. 
       FIGS. 13F-13H and 13J-13K  depict cross-sectional views of keys that may represent keys of the keyboard assembly  1335  in  FIG. 13E , viewed along section L-L in  FIG. 13E . In these figures, some components of keyboard assembly  1335  may be omitted or positioned in a different location, and some other components may be added. It will be understood that such differences are shown and described with relation to each cross-sectional view, and the differences may be understood to be capable of being applied to the keyboard assembly  1335  shown in  FIG. 13E . 
       FIG. 13F  depicts a cross-sectional view of a key that may be used in the keyboard assembly  1335  of  FIG. 13E . The keycap  1350 , which may be one of the keycaps  1337  of  FIG. 13E , is positioned above the cover  1336 . As shown in  FIG. 13F , the keycap  1350  may be larger than the opening in the cover  1336  (e.g., one of the openings  1339 ), such that a portion of the keycap  1350  (e.g., a peripheral portion) overlaps the cover  1336 . The keycap  1350  may be not secured (e.g., adhered) to the cover  1336 , thereby allowing the keycap  1350  and the cover  1336  to move independently of one another. For example, when the keycap  1350  is actuated (e.g., depressed), the portions of the keycap  1350  that overlap the cover  1336  may contact and deflect the cover  1336 . 
     The keycap  1350  may engage a key mechanism (e.g., one of the key mechanisms  1340  in  FIG. 13E ) through an opening in the cover  1336  (e.g., one of the openings  1339 ,  FIG. 13E ). For example, the keycap  1350  may clip to or otherwise engage a support mechanism  1351  of a key mechanism. The support mechanism  1351  may be a scissor mechanism, butterfly hinge, or any other suitable support mechanism, and may movably support the keycap  1350  relative to the base plate  1344 . 
     The membrane  1338  may be positioned below the cover  1336 . The membrane  1338  may provide several functions to the key shown in  FIG. 13F . For example, the membrane  1338  may have a portion that contacts the cover  1336  in a region  1352  proximate (e.g., immediately surrounding or adjacent) the opening. The membrane  1338  may be formed of a material that has sufficient rigidity to impart a force on the cover  1336  in the region  1352  to help prevent or limit sagging of the cover  1336 . More particularly, the membrane  1338  may contact the cover  1336  as shown in  FIG. 13F  at each key of a keyboard (or at least a subset of the keys), thereby forming an array of support areas, across the whole keyboard, for the cover  1336 . In this way the membrane  1338  ultimately provides a dimensional support for the cover  1336 . The membrane  1338  may be secured to the cover  1336  in the region  1352  with an adhesive or other suitable attachment technique, or it may contact the cover  1336  without being securely attached to the cover  1336 . The membrane  1338  may have any suitable shape, profile, contouring, etc. to allow the membrane  1338  to support the cover  1336  while also being able to deform and/or deflect when the keycap  1350  is depressed. 
     The membrane  1338  may also help prevent ingress of contaminants (e.g., dust, liquid, etc.) into the area below the keycaps. For example, as shown in  FIG. 13F , the membrane  1338  may contact or be attached to the keycap  1350  (e.g., with adhesive), thus forming a barrier between the external environment and the internal area of the device. Further, by securing the membrane  1338  to the keycap  1350  (e.g., via adhesive, radio frequency (RF) welding, fusing, or the like), the membrane  1338  will not separate from the keycap  1350  during keycap actuation, thus allowing the membrane  1338  to perform its barrier function during key actuation. 
     The membrane  1338  may be formed of any suitable material. In some cases, the membrane  1338  is formed of a material that has sufficient dimensional stability and/or stiffness to provide physical support to the cover  1336 . Further, the membrane  1338  may be formed of a material that has a tackiness or other material property that tends to cause debris, crumbs, dust, or other particulates to stick to the membrane  1338 . This may further increase the effectiveness of the barrier function of the membrane  1338 , as contaminants that come into contact with the membrane  1338  may stick to the membrane  1338  and therefore be prevented from moving around and becoming lodged in an undesirable location. Example materials for the membrane  1338  include silicone, polyurethane, polyisoprene, or the like. 
     As described above, the support  1343  may be positioned below the membrane  1338  to maintain the membrane  1338  in a desired location. Optionally, an additional support (e.g., the additional support  1353 ,  FIG. 13G ) may be positioned above the support  1343  and the membrane  1338  (and in contact with or otherwise close to the cover  1336 ) to help maintain the shape and/or position of the cover  1336 . The support  1343  and the additional support  1353  may be formed of or include any suitable material, such as metal, polymer, silicone, adhesive, or the like. Also, the membrane  1338  may be adhered or otherwise secured to the support  1343  and the additional support  1353 , or it may be not adhered/secured. 
       FIG. 13G  depicts a cross-sectional view of another key that may be used in the keyboard assembly  1335  of  FIG. 13E . It will be understood that an entire keyboard may be formed using the structure shown in  FIG. 13G  for each key or a subset of keys of the keyboard. The key shown in  FIG. 13G  is substantially similar to that shown in  FIG. 13F . Accordingly, details of the key structure that are described with respect to that key structure apply equally and/or by analogy to the key structure shown in  FIG. 13G , and will not be repeated here (e.g., with reference to the keycap  1350 , the cover  1336 , the support  1343 , the additional support  1353 , the key mechanism  1351 , etc.). In  FIG. 13G , however, the membrane  1354  (which may otherwise be the same as the membrane  1338 ) may terminate before contacting the keycap  1350 . Thus, the membrane  1354  may contact and/or support the cover  1336  as described above, but may not form a barrier that prevents ingress of contaminants to the key mechanism  1351 . 
       FIG. 13H  depicts a cross-sectional view of another key that may be used in the keyboard assembly  1335  of  FIG. 13E . It will be understood that an entire keyboard may be formed using the structure shown in  FIG. 13H  for each key or a subset of keys of the keyboard. The key shown in  FIG. 13H  is substantially similar to that shown in  FIG. 13F . Accordingly, details of the key structure that are described with respect to that key structure apply equally and/or by analogy to the key structure shown in  FIG. 13H , and will not be repeated here (e.g., with reference to the keycap  1350 , the cover  1336 , the support  1343 , the additional support  1353 , the key mechanism  1351 , etc.). In  FIG. 13H , however, the membrane  1355  (which may otherwise be the same as the membrane  1338 ) terminates before contacting the keycap  1350  (similar to the key in  FIG. 13G ), and the support  1343  is positioned above the membrane  1355 . Thus, the support  1343  may apply a force on the membrane  1355  that maintains the membrane  1355  in a particular position and prevents or reduces lateral and vertical movement of the membrane  1355 . Similar to the other key mechanisms shown, an additional support  1353  may be positioned above the support  1343  and may contact the cover  1336 . In other cases, the additional support  1353  may be omitted and the support  1343  may extend fully to the cover  1336 . In yet other cases, the additional support  1353  may be omitted and the support  1343  may be set apart from (e.g., not contact) the cover  1336 , at least while the key is in an unactuated state. 
       FIG. 13J  depicts a cross-sectional view of another key that may be used in the keyboard assembly  1335  of  FIG. 13E . It will be understood that an entire keyboard may be formed using the structure shown in  FIG. 13J  for each key or a subset of keys of the keyboard. The key shown in  FIG. 13J  is substantially similar to that shown in  FIG. 13F . Accordingly, details of the key structure that are described with respect to that key structure apply equally and/or by analogy to the key structure shown in  FIG. 13J , and will not be repeated here (e.g., with reference to the keycap  1350 , the support  1343 , the key mechanism  1351 , etc.). In  FIG. 13J , however, the cover  1356  (which may otherwise be the same as the cover  1336 ) is in contact with and optionally attached to the keycap  1350 , and a membrane may be omitted. The cover  1356  may be adhered or otherwise secured to the keycap  1350 , and may thus form a barrier to debris or other contaminants, performing a similar function to the membrane  1338  of  FIG. 13F . In order to avoid undesirable interference between the cover  1356  and the keycap  1350  (which may make the cover  1356  deform, may increase the actuation force of the keycap, or the like), the cover  1356  may include relief sections  1357  partially or completely surrounding the keycap  1350 . The relief sections  1357  may have any suitable shape and may be formed in any suitable manner (e.g., molding, embossing, etc.). 
       FIG. 13K  depicts a cross-sectional view of another key that may be used in the keyboard assembly  1335  of  FIG. 13E . It will be understood that an entire keyboard may be formed using the structure shown in  FIG. 13K  for each key or a subset of keys of the keyboard. The key shown in  FIG. 13K  is substantially similar to that shown in  FIG. 13F . Accordingly, details of the key structure that are described with respect to that key structure apply equally and/or by analogy to the key structure shown in  FIG. 13K , and will not be repeated here (e.g., with reference to the cover  1336 , the support  1343 , the membrane  1338 , the key mechanism  1351 , etc.). In  FIG. 13K , however, the keycap  1358  may include a recess  1360 . The ends of the cover  1336  and membrane  1338  that are adjacent to or define the openings may be received in the recess  1360 . This may help produce a seamless appearance to the keyboard, as there may be no visible gap around the perimeter of the keycaps and into the interior area of the keyboard. Moreover, the additional interlocking structure may help prevent ingress of contaminants under the keycap  1358 . 
     The keycap  1358  may include a top portion  1359  and a bottom portion  1361 . The top portion  1359  and the bottom portion  1361  may cooperate to define the recess  1360 . Accordingly, the key may be assembled by placing the top portion  1359  above the cover  1336  and membrane  1338  (and aligned with the openings in the cover  1336  and membrane  1338 ), and then attaching the bottom portion  1361  to the top portion  1359  through the openings, thus capturing portions of the cover  1336  and membrane  1338  in the recess  1360 . The top portion  1359  and the bottom portion  1361  may be attached in any suitable manner, including adhesives, mechanical interlocks, fasteners, welding, or the like. In other cases, the keycap  1358  may be a monolithic component that defines the recess  1360  (e.g., it may be a single molded polymer member). 
     Where the keycap  1358  includes a top portion  1359  and a bottom portion  1361 , these may be formed of or include any suitable materials, such as polymer, metal, glass, sapphire, or the like. Moreover, they may be the same material (e.g., the top and bottom portions  1359 ,  1361  may be formed from the same polymer material), or they may be different materials (e.g., the top portion  1359  may be glass and the bottom portion  1361  may be polymer). 
     As noted above, variations on the key shown in  FIG. 13K  are also possible. For example, the membrane  1338  may be omitted. Also, the membrane  1338  and/or the cover  1336  may be adhered or otherwise secured to the keycap  1358  within the recess. Other variations are also possible. 
     As noted above,  FIGS. 13F-13H and 13J-13K  depict cross-sectional views of keys that may represent keys of the keyboard assembly  1335  in  FIG. 13E . It will be understood that components, structures, structural relationships, and/or functions shown or described in one figure may be applied to other figures as well. For example, it will be understood that the extension of the membrane  1338  to the keycap  1350  in  FIG. 13F  may be applied to the key shown in  FIG. 13H  (which shows its membrane  1355  not contacting the keycap  1350 ). Other such modifications, variations, exclusions, and combinations of the disclosed concepts are also contemplated. 
       FIG. 13L  is an exploded view of a base portion  1365 , which may be an embodiment of the base portion  1301  of  FIG. 13A . In the base portion  1365 , a base plate  1368  is shaped to provide segments that extend upwards in the area between key caps of the keyboard, thus forming a key web like appearance. 
     With reference to  FIG. 13L , the base portion  1365  includes the top case  1316  that defines the opening  1315 . A keyboard assembly  1371  may be positioned in the opening  1315  when the base portion  1365  is assembled. The keyboard assembly  1371  also includes key mechanisms  1366  (including, for example, keycaps, support mechanisms, domes (or other components for providing tactile feedback), key make sensors (e.g., electrical switches, domes, capacitive sensing elements, etc.), and the like). 
     The key mechanisms  1366  may be electrically (and optionally mechanically) coupled to circuit substrates  1367 . The circuit substrates  1367  may be electrically coupled, through openings in the shaped base plate  1368  or around a peripheral side of the shaped base plate  1368 , to one or more components within the device to allow the device to detect key actuations. 
     The circuit substrates  1367  may be positioned in recesses  1369  (e.g., elongated troughs) that are defined by the shaped base plate  1368 . The circuit substrates  1367  may be secured to the shaped base plate  1368  (or to another component of the device) in any suitable way, including adhesives, fasteners, mechanical interlocks, heat stakes, or the like. The circuit substrates  1367  may be rigid or flexible circuit boards, or any other suitable component for facilitating detection of key actuations by the device and optionally mechanically supporting the key mechanisms. 
     The shaped base plate  1368  may be formed to define the recesses  1369  in which the keys may be positioned. The recesses  1369  may be at least partially defined by protrusions  1370  that extend upwards and are visible in the gaps between respective keys. As shown in  FIG. 13L , the recesses  1369  may be elongated trough-shaped recesses that receive a row of multiple keys. In other cases, as shown in  FIGS. 13M-130 , the recesses may have other configurations, such as separate recesses for each key. 
     The shaped base plate  1368  may be formed of any suitable material. For example, it may be metal, polymer, composite, metal alloy, glass, or any other suitable material. In some cases, the shaped base plate  1368  is stamped or drawn metal (e.g., a metal sheet that is subjected to stamping, drawing, or other forming operations), machined metal, or the like. 
     The keyboard assembly  1371  may also include a touch sensor  1372  (which may be the same as or similar to the touch sensors  1310 ,  1311 ,  1347  described above). A force sensing system may also be integrated with the base portion  1365  to facilitate detection of key presses, clicks, or the like, applied to the keyboard and/or non-keyboard regions of the base portion  1365 . 
     The base portion  1365  may also include a bottom case  1384 , which may be the same as or similar to other bottom cases described herein, such as the bottom case  1346  in  FIG. 13E . 
       FIG. 13M  depicts a portion of another embodiment of a shaped base plate  1373 . Whereas the shaped base plate  1368  in  FIG. 13L  defines elongated recesses  1369  (e.g., troughs), the shaped base plate in  FIG. 13M  depicts recesses  1374  that are sized and shaped for individual keys (though some groups of keys, such as directional or arrow keys, may share single recess which may be larger than and/or shaped differently than the recesses  1374 ). In such cases, key mechanisms positioned in the recesses  1374  may be electrically coupled to components within the device through openings in the shaped base plate, wirelessly, or the like. In some cases, as described herein, key actuations may be sensed through the shaped base plate (as well as any mechanical key components), such as with capacitive sensing. In other respects, such as the material(s) used and the method(s) of forming the shaped base plate, the shaped base plate  1373  may be the same as or similar to the shaped base plate  1368  of  FIG. 13L . 
       FIG. 13N  depicts a detail view of another embodiment of a base plate  1375 . In  FIG. 13N , additional wall segments  1376  are added to a shaped base  1378  that includes trough-shaped recesses, similar to those shown in  FIG. 13L . The shaped base  1378  may be the same as or similar to the shaped base plate  1368  of  FIG. 13L . 
     The additional wall segments  1376  extend from one protrusion  1377  to an adjacent protrusion  1377  and cooperate with the protrusions  1377  to form recesses defined by four walls. The additional wall segments and the protrusions formed in the shaped base  1378  may thus frame individual keys, providing a key web like appearance and structure around the keys. The additional wall segments  1376  may be configured to have a height that is less than the height of the protrusions  1377 . This may allow circuit substrates (such as the circuit substrates  1367  in  FIG. 13L ) to pass over the additional wall segments  1376  without protruding above the height of the protrusions  1377 . In other cases, the additional wall segments  1376  have substantially the same height as the protrusions  1377 . 
     The additional wall segments  1376  may be formed from any suitable material and may be formed in any suitable way. For example, the additional wall segments  1376  may be formed from metal, polymer, glass, composite materials, or the like. The additional wall segments  1376  may be attached to the shaped base plate  1378  via adhesives, fasteners, interlocking structures, or the like. In some cases, the additional wall segments  1376  may be formed and attached to the shaped base  1378  by a molding operation (e.g., co-molding, insert molding, overmolding, etc.). 
       FIG. 13O  depicts a detail view of another embodiment of a base plate  1379 . In  FIG. 13O , like  FIG. 13N , additional wall segments  1380  are added to a shaped base  1381  that includes trough-shaped recesses. The shaped base  1381  may be the same as or similar to the shaped base plate  1368  of  FIG. 13L . 
     In  FIG. 13O , however, the tops of the additional wall segments  1380  are substantially even with protrusions  1382 , while underpasses  1383  are defined below the additional wall segments  1380  and above the surface of the shaped base  1381 . The underpasses  1383  may allow for the circuit substrates (such as the circuit substrates  1367  in  FIG. 13L ) to pass below the additional wall segments  1380 . The additional wall segments  1380  may otherwise be similar in material and formation process to the additional wall segments  1376  in  FIG. 13N . 
     The key web like structure formed by the shaped base plates and optional additional wall segments, as described above, may be exposed (e.g., uncovered), and may be visible between keys. In other cases, the key web like structure may be covered by a fabric, membrane, or other cover, such as those described above with respect to  FIGS. 13C-13E . Indeed, a shaped base plate as described may be used in other keyboard configurations described herein. Similarly, features of other keyboard configurations may be incorporated into the keyboard configuration shown in  FIG. 13L . 
       FIG. 14A  depicts an example computing device  1400  that includes a base portion  1401  coupled to a display portion  1403 . The base portion  1401  may include a bottom case  1404  and a top case  1402 . The top case  1402  and the bottom case  1404  may be similar in structure, material, function, etc., to any of the top cases and bottom cases described herein. The computing device  1400  also includes a mechanical keyboard  1405  and a virtual key region  1408 , which may be similar in structure, material, function, etc., to the keyboard  1205  and the virtual key region  1208  discussed above. Like the top case  1202 , the top case  1402  may be a continuous member (e.g., lacking any openings or holes). 
     The top surface of the top case  1402  may define a plurality of recessed regions  1407  in which one or more keys of the keyboard  1405  (but less than all of the keys of the keyboard  1405 ) may be positioned. In some cases, the top case  1402  defines a distinct recess for each key of the keyboard  1405 . In other cases, the top case  1402  defines a distinct recess region for each of a subset of keys, and other recessed regions that accommodate more than one key. For example, each of the letter, character, and number keys of a keyboard may be disposed in a distinct recess region, while all of the arrow keys may be disposed in one common recessed region. 
     The recessed regions  1407  may have any suitable depth, as described above with respect to the recessed region  1307 . Moreover, the recessed regions  1407  may have any suitable dimensions. For example, the recessed regions  1407  may be configured to define a uniform gap (e.g., a gap  1414 ) between the walls of the recessed regions  1407  and the outer sides (e.g., the perimeter) of the keys that are positioned in the recessed regions  1407 . The gap  1414  may be any suitable distance, such as between about 0.1 mm and 1.0 mm. 
       FIG. 14B  is an exploded view of the base portion  1401  of  FIG. 14A . The base portion  1401  shows the keyboard  1405 , the top case  1402 , the bottom case  1404 , and a touch sensor  1410  below the top case  1402  (e.g., disposed within the interior volume defined by the top case  1402  and the bottom case  1404 ). 
     The touch sensor  1410  may be similar in structure, material, function, etc., to the touch sensors  1210 ,  1310 ,  1311  discussed above (or other touch sensors described herein). More particularly, the touch sensor  1410  may include a recessed region  1412  that substantially corresponds to and/or conforms to the various recessed regions  1407  in the top case  1402 . For example, the recessed region  1412  may be a single recessed region that accommodates all of the recessed regions  1407  of the top case  1402 . While this may increase the distance between some parts of the top case  1402  and the underlying touch sensor  1410 , such as between the web portions  1416  ( FIG. 14A ) of the top case  1402  and the touch sensor  1410 , these areas may be sufficiently small that the operation or effectiveness of the touch sensor  1410  is not unduly compromised. 
     The top case  1402  may be formed in any suitable manner, such as those described above with respect to the top case  1302 . For example, the top case  1402  may be slumped, molded, machined, etched, or the like, to form the recesses or recessed regions  1407 . 
       FIG. 15A  depicts an example computing device  1500  that includes a base portion  1501  coupled to a display portion  1503 . The base portion  1501  may include a bottom case  1504  and a top case  1502 . The top case  1502  and the bottom case  1504  may be similar in structure, material, function, etc., to any of the top cases and bottom cases described herein. Like the top case  1202 , the top case  1502  may be a continuous member (e.g., without any openings or holes). The computing device  1500  also includes a mechanical keyboard  1505  and a virtual key region  1508 , which may be similar in structure, material, function, etc., to the keyboard  1205  and the virtual key region  1208  discussed above. 
     The top surface of the top case  1502  may define a plurality of recessed regions  1507  in which rows of keys of the keyboard  1505  may be positioned. In some cases, the top case  1502  defines a distinct recess for each key row of the keyboard  1505 . In other cases, the top case  1502  defines a distinct recess region for a subset of keys in a particular key row, and other recessed regions that accommodate other keys in the particular key row. For example, each of the letter, character, and/or number keys of a key row may be disposed in a recessed region, while function keys (e.g., caps lock, return, tab, shift, etc.) may be disposed in another recessed region. 
     The recessed regions  1507  may have any suitable depth, as described above with respect to the recessed region  1307 . Moreover, the recessed regions  1507  may have any suitable dimensions. For example, the recessed regions  1507  may be configured to define a uniform gap (e.g., a gap  1514 ) between the walls of the recessed regions  1507  and the outer sides of the keys that are positioned in the recessed regions  1507 . The gap  1514  may be any suitable distance, such as between about 0.1 mm and 1.0 mm. Because the recessed regions  1507  are row-shaped, keys in the same recessed region  1507  may be separated by a substantially uniform distance, such as between about 1.0 mm and 7.0 mm. 
       FIG. 15B  is an exploded view of the base portion  1501  of  FIG. 15A . The base portion  1501  shows the keyboard  1505 , the top case  1502 , the bottom case  1504 , and a touch sensor  1510  below the top case  1502  (e.g., disposed within the interior volume defined by the top case  1502  and the bottom case  1504 ). 
     The touch sensor  1510  may be similar in structure, material, function, etc., to the touch sensors  1210 ,  1310 ,  1311 , and  1410  discussed above. More particularly, the touch sensor  1510  may include a recessed region  1512  that substantially corresponds to and/or conforms to the various recessed regions  1507  in the top case  1502 . For example, the recessed region  1512  may be a single recessed region that accommodates all of the recessed regions  1507  of the top case  1502 . 
     The top case  1502  may be formed in any suitable manner, such as those described above with respect to the top case  1302 . For example, the top case  1502  may be slumped, molded, machined, etched, or the like, to form the recesses or recessed regions  1507 . 
       FIGS. 12A-15B  illustrate computing devices that include a mechanical keyboard and a virtual keyboard. As noted above, computing devices as described herein, and in particular computing devices with an integrated interface system as described herein, may include one or more displays under the top case to produce images of buttons, icons, affordances, or any other visual output. For example, displays may be used to produce images of buttons or other affordances on the virtual keyboard. Displays may be integrated with the top case, and with touch and/or force sensors, in various ways. 
       FIG. 16A  depicts an example computing device  1600  that includes a base portion  1601  and a display portion  1603  coupled to the base portion  1601  (e.g., via a hinge). The base portion  1601  may include a bottom case  1604  and a top case  1602 , with the top case  1602  defining an input surface of an integrated input system. The top case  1602  and the bottom case  1604  may be similar in structure, material, function, etc., to any of the top cases and bottom cases described herein. 
     The computing device  1600  includes a virtual keyboard  1605  and a virtual key region  1608  on the top case  1602 . The virtual keyboard  1605  and virtual key region  1608  may include one or more displays, described herein, that produce images of buttons, keys, or other affordances that can be selected by the user. Force and/or touch sensors are used in conjunction with the virtual keyboard  1605  and virtual key region  1608  to detect selections of the affordances that are displayed on the virtual keyboard  1605  and virtual key region  1608 . 
     The computing device  1600  also includes a trackpad region  1610 , which may correspond to any location on the top case  1602  other than the virtual keyboard  1605  and virtual key region  1608  (e.g., including a palm rest region below the virtual keyboard  1605  and/or the areas along the lateral sides of the virtual keyboard  1605 ). The virtual keyboard  1605 , the virtual key region  1608 , and the trackpad region  1610  may all be part of or define a touch-input region of the computing device  1600 . For example, touch and/or force inputs may be detected on any of these regions, and inputs that span regions (e.g., gestures starting in the virtual key region  1608  and ending in the trackpad region  1610 ) may be detected. 
     The trackpad region  1610  may optionally include or be associated with a display or an illuminated mask layer as well. A display may be used, for example, to display input areas, buttons, keys, or other affordances. As one example, a display underlying the trackpad region  1610  may produce an image of a border (e.g., representing or replicating an image of a trackpad) that indicates where a user may provide touch inputs. As another example, the display may produce an image of a slider that a user can select and/or move to change a volume setting of the computing device  1600 . These are merely some examples, and numerous other images and objects can be displayed, and inputs to the trackpad region  1610  may affect numerous settings and operations of the computing device  1600 . 
     The different regions of the top case  1602 , including the trackpad region  1610 , the virtual keyboard  1605 , and the virtual key region  1608 , may have the same or different textures, finishes, colors, or other physical properties or appearances. In some cases, substantially the entire surface of the top case  1602  has a uniform texture and appearance. In other cases, different regions have different textures or appearances. For example, the virtual key region  1608  may have a polished, smooth surface, while the virtual key region  1608  and the trackpad region  1610  may have a textured surface (e.g., dimpled, roughened, or the like). 
     The particular textures of these regions may be selected to produce a desired tactile feel during user interactions. For example, the virtual keyboard  1605  may be used for tap or touch inputs (e.g., without sliding or gesture inputs), and as such may have a smooth, polished surface. Smooth surfaces may, for example, prevent unintentional slipping of fingers or other input devices. The trackpad region  1610  and the virtual key region  1608 , on the other hand, may be used for gesture inputs, such as finger or stylus swipes, and may have a roughened, textured, or otherwise less smooth surface. Such surface textures may reduce friction and/or sticking of fingers or other input devices during such inputs. Regions of different textures may be formed on a single, continuous top case  1602  (e.g., a continuous glass sheet) using any suitable techniques, such as abrasive blasting (e.g., sand blasting), chemical or physical etching, laser etching, grinding, polishing, lapping, or the like. In some cases, masks or shields may be used during processing to define areas which are to have different textures. For example, a mask may be applied to the virtual keyboard region  1605  while an etching or grinding operation is applied to the virtual key region  1608  and the trackpad region  1610 . 
     The boundaries between the textures of different regions may indicate the boundaries of the input and/or output functionality provided by those regions. For example, the trackpad region  1610  (or a portion thereof) may be textured only in the area where touch inputs are actually sensed. Thus, the user will be able to differentiate, tactilely and/or visually, between a touch-sensitive trackpad input area and a non-touch-sensitive portion of the top case  1602 . While the textured top case regions are described with respect to  FIG. 16A , it will be understood that the same concepts and processes may apply equally to any of the top cases described herein. 
       FIG. 16A  illustrates the virtual keyboard  1605  in a traditional layout. However, because the images of the keys of the virtual keyboard  1605  are produced by a display below the top case, different keyboards may be displayed instead. For example,  FIG. 16B  depicts the computing device  1600  with a virtual keyboard  1612  in an alternate configuration (e.g., an ergonomic configuration). As another example,  FIG. 16C  depicts the computing device  1600  with a virtual keyboard  1613  in yet another alternate configuration. In this particular example, instead of a character-input layout, the virtual keyboard  1613  defines areas for other types of inputs and/or manipulations. Such an input may be used for controlling a game, where one input area (e.g., on the left side of the computing device  1600 ) controls a direction input, while other input areas (e.g., on the right side of the computing device  1600 ) may control discrete inputs. As shown, the input areas on the left side of the computing device  1600  define regions that may correspond to the fingertips of a user&#39;s hand, but this is merely one example configuration. 
     Other keyboard configurations are also possible, such as positioning a keyboard nearer the front of the computing device  1600  (e.g., the locations of the virtual keyboard  1605  ( FIG. 16A ) and the trackpad region  1610  may be swapped), or displaying keyboards with different alphabets or symbols, or the like. Also, the particular keyboard that is displayed (and/or the location of the keyboard) may be automatically selected by the computing device  1600  based on an operational state of the device, such as the particular program that is being executed, what is being displayed on an associated display screen, or the like. 
     In order to actuate keys of a virtual keyboard as described above, a user may simply tap or press on a portion of the surface of the top case  1602  on which a key is displayed. In some cases, however, a virtual keyboard may be used in conjunction with a keyboard accessory that can be applied to the top case  1602 .  FIG. 16D  illustrates the computing device  1600  with a keyboard accessory  1614  shown above the top case  1602 . The keyboard accessory  1614  may include a base portion  1616  and keys  1618 . The base portion  1616  and the keys  1618  may be a monolithic component, such as a molded silicone accessory. In some cases, the material may deform under a typical typing force to provide a tactile feedback or sensation of typing on a mechanical or movable keycap. Alternatively, the material may not deform under typical typing pressures, and the keys  1618  may simply provide raised, nonmoving key pads for a user to strike during typing. 
     In some cases, the keyboard accessory  1614  may include mechanical key mechanisms for the keys  1618 , including, for example, keycaps, mechanisms, domes (or other components for providing tactile feedback), key make sensors (e.g., electrical switches, domes, capacitive sensing elements, etc.), and the like. The keyboard accessory  1614 , and in particular the keys  1618 , may also include components that facilitate key make sensing by a sensor underlying the top case  1602 , such as metal or conductive elements that can be sensed by a capacitive sensor inside the computing device  1600 . 
     The keyboard accessory  1614  may be light-transmissive (e.g., transparent) such that glyphs, symbols, characters, or other images may be displayed on the top case  1602  by a display within the base portion  1601  and visible through the keys  1618 . Accordingly, while the keyboard accessory  1614  may provide fixed, physical keys on which users may type, the function of those keys (e.g., what character will appear when a particular key is struck) may be changed dynamically. For example,  FIG. 16D  shows a standard QWERTY keyboard  1617  displayed on the top case  1602 , which may be visible through the keyboard accessory  1614 , as shown in  FIG. 16F .  FIG. 16E  shows the computing device  1600  displaying an alternative keyboard  1620  (e.g., alternative glyphs or characters), which may be visible through the keyboard accessory  1614  when the keyboard accessory  1614  is applied to the top case  1602 . In order to allow images on the display to be visible through the keyboard accessory  1614 , the keyboard accessory  1614  may be made from materials that have a same or similar refractive index as the top case  1602 . Moreover, where the keyboard accessory  1614  includes multiple components (e.g., keycaps, keyboard substrates or base portions, elastomeric biasing members, etc.), the multiple components may have the same or similar refractive indices. In this way, bending, diffraction, distortion, magnification (or other optical phenomena) of the images displayed through the top case  1602  and the keyboard accessory  1614  may be reduced or eliminated. 
     The keyboard accessory  1614  may be configured to be positioned in one location on the top case  1602 . In such cases, the keyboard accessory  1614  and/or the top case  1602  (and/or any other portion or area of the computing device  1600 ) may include optical and/or physical guides to help a user position the keyboard accessory  1614  on the top case  1602 . For example, the top case  1602  and the keyboard accessory  1614  may have complementary protrusions and recesses (or any other suitable alignment features) that engage with each other to properly locate the keyboard accessory  1614 . As another example, the top case  1602  and/or the keyboard accessory  1614  may have registration marks, lines, arrows, or other visual indicators that indicate where and/or how the keyboard accessory  1614  is to be positioned. Of course, the computing device  1600  may be configured to be used with or without the keyboard accessory  1614 . For example, if a keyboard without physical keys is desired, a user may simply forgo use of the keyboard accessory  1614  and instead type directly on the top case  1602 . 
     In some cases, the keyboard accessory  1614  may be applied anywhere on the top case  1602 . For example,  FIG. 16F  shows the computing device  1600  with the keyboard accessory  1614  applied to the top case  1602  above the trackpad region  1610 , and nearer to the display portion  1603  than the front edge of the computing device  1600 .  FIG. 16G , on the other hand, shows the keyboard accessory  1614  applied to the top case  1602  below a trackpad region  1622 , and further from the display portion  1603 . 
     The computing device  1600  may detect a particular location and/or positioning of the keyboard accessory  1614  and display glyphs, symbols, or other images in suitable positions below the keyboard accessory  1614  to coincide with the keys  1618  of the keyboard accessory  1614 . For example, the keyboard accessory  1614  may include components  1624 , such as magnets, metal or conductive pieces, radio-frequency tags, or the like, that can be sensed or otherwise detected by the computing device  1600 . When the keyboard accessory  1614  is applied to the computing device  1600 , the computing device  1600  may determine information from the components  1624 , such as the location of the keyboard accessory  1614  on the top case  1602  and the key layout of the keyboard accessory  1614  (e.g., by consulting a lookup table to correlate information detected from the keyboard accessory  1614  with a particular model, keyboard layout, or other information about the keyboard accessory  1614 ). Once the computing device  1600  has determined the key layout and the location of the keyboard accessory  1614 , it can display images on the top case  1602  at locations that coincide with the keys  1618  and that are visible through the keys  1618 . 
       FIG. 17A  depicts an exploded view of an example base portion  1701   a , which may generally correspond to the base portion  1601  of  FIG. 16A . The base portion  1701   a  includes a top case  1702   a  (corresponding to the top case  1602 ), a bottom case  1704   a  (corresponding to the bottom case  1604 ), and a touch sensor  1706   a  below the top case  1702   a  (e.g., disposed within the interior volume defined by the top case  1702   a  and the bottom case  1704   a ). The base portion  1701   a  also includes a display  1708  below the touch sensor  1706   a.    
     Portions of the touch sensor  1706   a  and the top case  1702   a  may be transparent to allow the display  1708  to be viewed through the top case  1702   a  and the touch sensor  1706   a . Some portions of the top case  1702   a  and/or the touch sensor  1706   a  may be substantially opaque, for example to define and visually distinguish regions that are not touch sensitive, or to cover or occlude internal components. 
     The display  1708  has a first display component  1710 , a second display component  1712 , and a third display component  1714 . The first display component  1710  is positioned under the virtual key region  1608  ( FIG. 16A ) and displays images for the virtual key region  1608 . The second display component  1712  is positioned under the virtual keyboard region  1605  ( FIG. 16A ), and displays images for the virtual keyboard region  1605 , such as images or representations of keys. The third display component  1714  may be used in implementations where the trackpad region  1610  ( FIG. 16A ) is transparent and/or is configured to display images. Where a trackpad region  1610  is not associated with a display, the third display component  1714  may be omitted. The first, second, and third display components may include or be associated with any suitable display components, such as LCDs, LEDs, OLEDs, backlights, side lights, filter layers, light diffuser layers, light guides, or the like. 
     The first, second, and third display components may be separated physically and operationally, each including its own unique hardware and software components, such as its own LCD array and light source, or its own OLED array. Alternatively, they may share one or more components, such as a processor, a backlight, or the like. Providing discrete display components for the different display regions may increase the space available for other components, as regions that do not require a display can be free of display components, leaving more space for other components. Also, when one of the discrete displays is not being used it can be turned off or blacked out independent of the other displays. 
       FIG. 17B  depicts an exploded view of another example base portion  1701   b , which may generally correspond to the base portion  1601  of  FIG. 16A . The base portion  1701   b  includes a top case  1702   b  (corresponding to the top case  1602 ), a bottom case  1704   b  (corresponding to the bottom case  1604 ), and a touch sensor  1706   b  below the top case  1702   b  (e.g., disposed within the interior volume defined by the top case  1702   b  and the bottom case  1704   b ). As noted above, portions of the touch sensor  1706   b  and the top case  1702   b  may be transparent, while some portions of the top case  1702   b  and/or the touch sensor  1706   b  may be substantially opaque, for example to define and visually distinguish regions that are not touch sensitive, or to cover or occlude internal components. 
     The base portion  1701   b  also includes a display  1716  below the touch sensor  1706   b . Whereas the display  1708  in  FIG. 17A  had three distinct displays (each corresponding to a different input/output region), the base portion  1701   b  includes only a single display  1716  that spans all of the input/output regions. For example, the display  1716  may be substantially coextensive with the top case  1702   b . Different regions of the display  1716  can be used to produce images or other graphical objects on different regions of the top case  1702   b , such as a keyboard region (e.g., the virtual keyboard region  1605 ,  FIG. 16A ), a virtual key region (e.g., the virtual key region  1608 ,  FIG. 16A ), and a trackpad region (e.g., the trackpad region  1610 ,  FIG. 16A ). 
     In conventional computing devices with keyboards, key mechanisms, which are exposed on the outside of the device, mechanically couple to components within the device. For example, a keycap may physically connect to a dome switch (or other component) that is attached to a circuit board within the device. A top case of such a device may have openings or holes through which the keycap physically engages the component(s). As noted above, however, an integrated interface system as described herein may include a continuous top case, such as a glass top case, that does not include any openings or holes in the input surface. Such continuous top cases, however, do not permit a physical connection between keys and interior circuit boards. Such top cases thus prevent the use of traditional physical couplings between keys and interior circuit boards to detect key presses. As noted above, one technique for detecting key presses, as well as other touch inputs applied to the top case of an integrated interface system, is to include a touch sensor below portions of the top case that are configured to receive touch inputs. This may include, for example, a keyboard region, a non-keyboard region, a virtual key region, or other regions of the top case. 
       FIG. 18A  depicts an exploded view of part of a base portion of a computing device. More particularly,  FIG. 18A  depicts an example top case  1802  and a touch sensor  1804 . The top case  1802  may be formed from glass, ceramic, or any other suitable material, and may not have any openings or holes. The top case  1802  may include mechanical or virtual keys, or a combination of mechanical and virtual keys. 
     Below the top case  1802  is a touch sensor  1804 . The touch sensor  1804  may be any suitable type of touch sensor, and may use any suitable touch-sensing technology. For example, the touch sensor  1804  may be a capacitive touch sensor that detects touch inputs by detecting a change in capacitance caused by the presence of a finger (or other implement) on or near the top case  1802 . In such cases, the touch sensor  1804  may include one or more layers with conductive traces  1806  disposed thereon. The conductive traces  1806  may act as plates of capacitors, between which capacitance is measured. The conductive traces  1806  may be conductive material, such as indium tin oxide (ITO), indium gallium oxide, gallium zinc oxide, indium gallium zinc oxide, metal nanowire, nanotube, carbon nanotube, graphene, conductive polymers, a semiconductor material, a metal oxide material, copper, gold, constantan, or any other suitable material, and may be disposed on a substrate such as a circuit material (e.g., a flex circuit). In cases where the top case  1802  is transparent and the conductive traces  1806  are in a display path (e.g., between a display and the top case  1802 , the conductive traces  1806  may be substantially transparent (e.g., using ITO). In cases and/or regions where the top case  1802  is not transparent, is painted, or where transparency of the conductive traces  1806  is otherwise not necessary, the conductive traces  1806  may be formed from a non-transparent material, such as solid metal traces (e.g., copper, gold, silver, etc.). The touch sensor  1804  may include other layers or components, including dielectric materials, substrates, connectors, electrodes, and the like. 
     The touch sensor  1804  may be substantially transparent, such as where a display (e.g., the display  1708  or  1716 ,  FIGS. 17A-17B ) is positioned under the touch sensor  1804  and displays images through the touch sensor  1804 . Where no display is used or where light or images do not need to pass through the touch sensor  1804 , it may be non-transparent. The touch sensor  1804  may be in contact with the top case  1802 , attached to the top case  1802 , or it may be set apart from the top case  1802  by a gap (which may be a layer of material or an empty space). 
     The touch sensor  1804  may be sized to provide touch sensing to substantially the entire top surface of the top case  1802  (e.g., the touch sensor  1804  may extend over substantially an entire area of the top case  1802 , or at least an entire area of the top case  1802  that defines a top surface of a base portion). Accordingly, the touch sensor  1804  may be used to detect touch inputs applied to anywhere on the top case  1802 . More particularly, the touch sensor  1804  can detect touch inputs that are similar to those typically detected by a trackpad, such as taps, swipes, gestures, and multi-touch inputs. By disposing the touch sensor  1804  below a keyboard, similar inputs may be detected when applied to the keys of a keyboard (whether it is a virtual or a mechanical keyboard). For example, in addition to detecting key presses of a keyboard, the touch sensor  1804  may detect swipes, gestures, and multi-touch inputs that are applied to the keys of a keyboard. Also, because the touch sensor  1804  spans both key and non-key regions, swipes, gestures, and multi-touch inputs can begin on the keys (or even the keycaps of a mechanical key) and end outside the keyboard region (or vice versa). Accordingly, the entire top case of a computing device effectively acts as a trackpad, even the surfaces of the keys (e.g., the keycaps) themselves. Techniques for detecting inputs applied to keys, including both key presses and touch inputs (e.g., gestures), are discussed herein. Touch sensors as described herein may also be used to detect the location of fingers or other implements that are not in physical contact with the top case  1802 . For example, touch sensors may detect the presence or location of a finger that is hovering above the top case  1802 . As described herein, this information may be used for various purposes, such as to determine intended key targets for the purposes of spelling suggestions, automatic spelling/grammar corrections, or any other suitable purpose. 
     The top case  1802  in  FIG. 18A  is substantially flat or planar (e.g., it defines a planar top exterior surface of the top case  1802  and thus of a base portion of a computing device). Accordingly, the touch sensor  1804  is also substantially planar, allowing a close coupling between the top case  1802  and the touch sensor  1804 . As noted above, however, a top case may have one or more recesses, such as a recessed region in which a keyboard may be positioned.  FIG. 18B  illustrates a top case  1808   b  having a recessed region  1810   b , and a touch sensor  1812  having a recessed region  1814 . The top case  1808   b  and touch sensor  1812  are similar to the top case  1302  and touch sensor  1310  described with respect to  FIG. 13B . Conductive traces  1816 , similar to the conductive traces  1806  described above, may be disposed on the touch sensor  1812 . The conductive traces  1816  may extend continuously across the recessed region  1814  and surrounding non-recessed regions, thus forming a single, integrated touch sensor over the whole top case. 
     The recessed region  1814  of the touch sensor  1812  may be formed by folding a flat substrate (e.g., flexible circuit material, Mylar, etc.) that has been cut or shaped to produce the desired three-dimensional shape. For example,  FIG. 18C  shows a portion of a substrate  1832  having a shape that, when folded along fold lines  1833  (according to the arrows  1834 ), produces the touch sensor  1812  shown in  FIG. 18B .  FIG. 18C  shows the same portion of the substrate  1832  after it has been folded. The substrate  1832  may be folded after being partially coupled to the top case  1808   b . For example, the substrate  1832  may be attached to the bottom of the recessed region  1810   b , and then the remainder of the substrate  1832  may be folded to conform to the other regions of the top case  1808   b.    
       FIG. 18E  depicts another example top case  1808   e , similar to the top case  1808   b , having a recess or recessed region  1810   e . Instead of a single, continuous touch sensor, however,  FIG. 18E  depicts a touch-sensing system  1818  having several discrete touch sensors that, together, provide touch input capabilities to substantially the entire top case  1808   e . In particular, the touch-sensing system  1818  includes a first touch sensor  1820  positioned below the recess  1810   e , and provides touch sensing (including key press sensing, gesture sensing, and multi-touch sensing) to a keyboard that is positioned in the recess  1810   e . The touch-sensing system  1818  also includes a second touch sensor  1822  positioned below and provides touch sensing to a region where a virtual key region (e.g., the virtual key region  1208 ,  FIG. 12A ) may be located. The touch-sensing system  1818  also includes a third touch sensor  1824  positioned below a palm rest or trackpad region  1817 , and fourth touch sensors  1826  positioned along the sides of the recessed region  1810   e . Any of the forgoing touch sensors may be omitted if no touch sensing functionality is to be provided for a particular region. 
       FIG. 18F  depicts an example top case  1828  that has conductive traces  1830  disposed directly thereon. For example, the top case  1828  may be formed from a glass, ceramic, or other light-transmissive dielectric material. Instead of applying conductive traces to a separate substrate and positioning the substrate on or near the top case  1828 , conductive traces  1830  may be disposed directly on the bottom surface of the top case  1828 . The conductive traces  1830  may be formed from or include any suitable material, such as ITO, indium gallium oxide, gallium zinc oxide, indium gallium zinc oxide, metal nanowire, nanotube, carbon nanotube, graphene, conductive polymers, a semiconductor material, a metal oxide material, copper, gold, constantan, or the like. Where the top case  1828  is transparent, such as when it is used in conjunction with one or more displays to produce virtual keys or other images on the top case  1828 , the conductive traces  1830  may be transparent or substantially transparent. Where the top case  1828  is not transparent, the conductive traces  1830  may be transparent or not transparent. The conductive traces  1830  may be disposed on the top case  1828  in any appropriate manner, such as lithography, chemical or physical vapor deposition, nozzle deposition (e.g., printing), or the like. 
     While the foregoing examples show touch sensors positioned under a top member of a top case, and thus configured to detect touch inputs on the top surface of the top case, touch sensors may also be positioned and configured to detect touch inputs on side surfaces of a top case. For example, in cases where a top case defines sidewalls, touch sensors and/or touch sensing components (e.g., electrode layers) may be positioned against or otherwise near the interior surfaces of the sidewalls. Touch inputs applied to the sidewalls, such as taps, swipes, etc., may be detected by the touch sensors to cause the device to perform one or more operations. 
     As noted above, top cases, such as single-sheet glass top cases, may be reinforced to increase the structural integrity (e.g., stiffness, strength, etc.) of the top case and the computing device overall. Additionally, top cases may include reinforcing and/or stiffening features that help define distinct touch and/or force input regions. For example, reinforcements, ribs, or other features may help prevent a touch or force input that is applied to one region of the top case from causing deflection or deformation in another region of the top case. 
       FIG. 19A  depicts an example top case  1900  that includes reinforcements  1902  on the bottom surface of the top case  1900 . The reinforcements are shown as integral to the top case  1900 , though they may be separate components that are attached to the top case, as described above with respect to  FIGS. 8A-9B . 
     The reinforcements  1902  define several distinct regions. A first region  1910  may correspond to a portion of the top case  1900  on which a keyboard is disposed (either a virtual or mechanical keyboard). A second region  1904  may correspond to a trackpad region. Third and fourth regions  1906 ,  1908  may be additional touch-input regions, and may correspond to a palm rest area where users may rest their hands during typing. These regions are merely examples, and other configurations of the reinforcements  1902  are also contemplated. 
     The regions defined by the reinforcements  1902  may be configured to isolate the effects of touch and/or force inputs to particular regions. For example, the reinforcements  1902  may help prevent forces applied within the first region  1910 , such as selections of mechanical keys, from causing deflections in the second or trackpad region  1904  that could be incorrectly identified as clicks or touch inputs to the second region  1904 . Similarly, the reinforcements  1902  may reduce the deflection caused in the first or second regions  1910 ,  1904  from a user&#39;s palms resting on the third and fourth regions  1906 ,  1908 . 
       FIG. 19B  depicts a partial cross-sectional view of the top case  1900  viewed along section F-F in  FIG. 19A . As shown, the reinforcement  1902  forms a rib that extends from a bottom surface of the top case  1900 . The reinforcement  1902  may be formed by any suitable process, including machining, etching, ablating, or the like. 
     The reinforcements  1902  may contact or engage structures positioned below the top case  1900  (e.g., within the interior volume of the device) to provide additional support to the top case and further isolate the various regions.  FIG. 19C , for example, depicts a partial cross-sectional view of the top case  1900  viewed along section F-F in  FIG. 19A , showing a component  1912  below the top case  1900  and in contact with the reinforcement  1902 . The component  1912  may be any component, such as a bottom case (e.g., the bottom case  110 ,  FIG. 1A ), or any other component within a base portion of a computing device. As another example,  FIG. 19D  depicts a partial cross-sectional view of the top case  1900  viewed along section F-F in  FIG. 19A , showing a shim  1914  below the top case  1900  and in contact with the reinforcement  1902 . The shim  1914  may be any material, such as plastic, metal, foam, etc., and it may rest on another component  1916  (e.g., the bottom case  110 ,  FIG. 1A ), or any other component within a base portion of a computing device. 
     The reinforcement  1902  may be secured (e.g., via an adhesive, fastener, or the like) to the component  1916  or the shim  1914 , or it may be unsecured (e.g., it may simply rest on or contact the component  1916  or the shim  1914 ). The reinforcement  1902  may be unsecured to the component  1916  or shim  1914  to allow some side-to-side or lateral movement of the reinforcement  1902  with respect to the component  1916  or shim  1914 . Where the shim  1914  is used ( FIG. 19D ), the bottom surface of the shim may be secured (e.g., via an adhesive, fastener, or the like) to the component  1916 , or it may be unsecured. 
       FIGS. 20A-20C  depict another example of a top case  2000  having reinforcements. In particular, the top case  2000 , which may be similar to the other top cases described herein, may include reinforcements  2006 , such as ribs that are attached to the bottom surface of the top case  2000 . The reinforcements  2006  may be similar in structure, material, function, etc., to the reinforcements  1902  discussed above. 
     The top case  2000  may also include reinforcement plates  2004 ,  2008  attached to the bottom surface of the top case  2000 . For example, a first reinforcement plate  2004  may be positioned under a keyboard region  2001 , and a second reinforcement plate  2008  may be positioned under a trackpad region  2003 . 
     The reinforcement plates  2004 ,  2008  may provide more uniform deflections in response to force inputs applied at different locations on the top case  2000 . This may help improve force sensing, as a force applied to a corner of the trackpad region  2003  (e.g., at or near a corner of the second reinforcement plate  2008 ) may cause the entire trackpad region  2003  to move, rather than just a localized portion under the applied force. This may allow for more flexibility in the placement of force sensors, and may result in more consistent and/or accurate detections of force inputs.  FIG. 20B  depicts a partial cross-sectional view of the top case  2000  viewed along section G-G in  FIG. 20A , showing the reinforcements  2006  and the second reinforcement plate  2008 .  FIG. 20C  depicts the same view as  FIG. 20B , but shows the top case  2000  when a force is applied to a central portion of the trackpad region  2003 . As shown, the local force due to a user&#39;s finger in the center of the trackpad region  2003  causes a substantially uniform deflection of the trackpad region  2003 , rather than a localized deformation. Moreover, the deflection is substantially isolated to the trackpad region  2003 , thus preventing or reducing cross-talk between regions of the top case  2000 . 
       FIGS. 21A-21D  depict schematic views of an input surface having an integrated force sensor or force-sensing capabilities. Generally, the input surface may be configured to detect a magnitude or degree of force applied to the surface of a device by measuring a small level of deflection or displacement of the input surface. A force sensor may be configured to measure the deflection or displacement and produce an electrical response or signal that corresponds to the degree or amount of force applied to the surface of the device. 
     Force sensors and associated processors and circuitry may be configured to register inputs when a determined force satisfies (e.g., meets and/or exceeds) a force threshold (and when the location of the determined force is at a particular location). For example, if a force below a force threshold is determined or detected on a key region, the force sensor may ignore that input or otherwise not cause the device to take a particular action (e.g., the device will not register a key input). If the force on the key region exceeds the threshold, the device may register the input as a key input and take an appropriate action, such as displaying a letter or character corresponding to that key on a display. The particular threshold that must be satisfied in order for a force sensor or device to register an input in response to a particular input may be any suitable threshold, and the threshold may be changed based on various factors. For example, the threshold may be dynamically set to a first value if it is determined (e.g., based on an average force value detected by the force sensor) that a user has a light typing style. That same device may set the threshold to a second value, higher than the first value, if it is determined that a user has a heavier typing style. Dynamically adjusting the threshold for force inputs may help improve the accuracy of key press detection in some circumstances, as it may easier to ignore inadvertent touches, taps, bumps, or other contacts on an input surface when the force associated with the user&#39;s typical typing/key input is known to a greater degree. Further, different thresholds may be established for different locations on an input surface. For example, if it is determined that a user applies more force with an index finger than a pinky finger, a device may establish a lower force threshold for keys or input regions that are typically associated with the pinky finger than for those that are typically associated with an index finger. These and other techniques may be implemented using any suitable force sensor or combination of force (and/or other) sensors. 
       FIGS. 21A-21D  depict two example force-sensing configurations that may be used in a computing device as described herein: a global-deflection sensing configuration  2100 , as illustrated in  FIGS. 21A-21B , and a local-deflection sensing configuration  2150 , as illustrated in  FIGS. 21C-21D . Either or both of the sensing configurations  2100  and  2150  may be incorporated into the computing device  100  of  FIG. 1A . The force-sensing configurations may be used alone or in conjunction with the capacitive touch sensing configurations described herein with respect to other embodiments. 
       FIGS. 21A-21B  depict a sensing configuration  2100  in which a global deflection  2106  of an input surface  2102  of a top case  2104  is measured using an appropriate force sensor positioned below or integrated with the top case  2104 .  FIG. 21A  depicts the configuration  2100  in an un-deflected state and  FIG. 21B  depicts the configuration  2100  in a deflected state (having a displacement or deflection  2106 ) occurring in response to a force applied by an object  2110  (e.g., a user&#39;s finger). By measuring a global deflection  2106  or displacement of the top case  2104 , both a location and a magnitude of an applied force may be measured. Furthermore, by measuring a global deflection  2106  of the top case  2104  an average or overall force, that may be generally location independent, may be sensed. Example force sensors that are configured to measure a global deflection  2106  are described below with respect to  FIG. 47 . 
       FIGS. 21C-21D  depict a sensing configuration  2150  in which a localized deflection  2156  of an input surface  2152  of a top case  2154  is measured using an appropriate force sensor positioned below or integrated with the top case  2154 .  FIG. 21C  depicts the configuration  2150  in an un-deflected state and  FIG. 21D  depicts the configuration  2150  in a deflected state (having deflection  2156 ) occurring in response to a force applied by an object  2160  (e.g., a user&#39;s finger). By measuring a localized deflection  2156  or displacement of the top case  2154 , both a location and a magnitude of an applied force may be measured. Furthermore, by measuring a localized deflection  2156  of the top case  2154 , multiple forces due to multiple touches along the input surface  2152  may be individually sensed. Example force sensors that are configured to measure a localized deflection  2156  are described below with respect to  FIG. 47 . 
     In some instances, the input surface or top case of a device may employ both a global-deflection force-sensing configuration (e.g.,  2100  of  FIGS. 21A-21B ) and a local-deflection force-sensing configuration (e.g.,  2150  of  FIGS. 21C-21D ). In some implementations, the two force-sensing configurations may be used to detect different types of user input. For example, a local force-sensing configuration  2150  may be used to invoke a first type of command. The first type of command may correspond to a location-dependent or cursor-driven action associated with a graphical user interface. Within the same device, a global force-sensing configuration  2100  may be used to trigger a second, different type of command, which may be a location independent action that does not depend on the location of a cursor within a graphical user interface. 
     Additionally or alternatively, using both force sensing configurations in conjunction may enable the device to determine the type of input or force that is being applied to the input surface, which may be beneficial in distinguishing non-intentional input or inadvertent contact or force from intentional force input. For example, a general or large-area deflection  2106  measured using configuration  2100  may be used to establish a baseline force caused by a portion of the hand (e.g., a palm) resting on the input surface while a localized or small area deflection  2156  measured using configuration  2150  may be used to distinguish a force applied by an input object  2110  (e.g., a user&#39;s finger), which may correspond to an intentional force input. 
       FIGS. 22A-22D  depict example force sensors that can be used to implement a force sensing scheme similar to the force sensing configurations  2100  and  2150  described above with respect to  FIGS. 21A-21D . As described in more detail below, some of the force sensors are better adapted for sensing a localized deflection while others may be better adapted for sensing a global deflection or displacement. 
       FIG. 22A  depicts a first force sensor  2200   a  that is configured to detect a global or large-area deflection of a top case  2204   a  having an input surface  2202   a . The first force sensor  2200   a  may operate on a self-capacitive sensing scheme in which one or more electrodes  2220   a  of an electrode array may be used to detect a change in capacitance  2215   a  between a respective electrode  2220   a  and an object  2210   a  (e.g., a user&#39;s finger) applying a force to the input surface  2202   a . In an example embodiment, the top case  2204   a  is separated from the electrodes  2220   a  by a compressible layer  2206   a , which may include a compressible medium or material. Example compressible media include a foam, gel, elastomeric material, air, or other compliant material and combinations thereof. 
     In the first force sensor  2200   a , the capacitance  2215   a  may change as a force applied by object  2210   a  depresses or displaces the top case  2204   a  toward the electrodes  2220   a  thereby compressing the compressible layer  2206   a . The change in capacitance  2215   a  may correspond to a degree or amount of force applied, which may correspond to a predicable compressibility response or spring force of the compressible layer  2206   a . Force-sensing circuitry operably coupled to the first force sensor  2200   a  may be used to measure the change in capacitance  2215   a  and produce a signal that corresponds to the amount or degree of force applied by the object  2210   a.    
     In some implementations, the top case  2204   a  may be substantially rigid or non-compliant over the localized region corresponding to the touch of the object  2210   a . Example materials that may be used to form the top case  2204   a  may include glass, sapphire, polymer, ceramic, metal, and/or composite materials that are configured to produce the corresponding non-deforming structural response to an applied force. In some cases, the top case  2204   a  is formed from a laminate of materials that is specially configured to reduce or eliminate localized deformation in response to the touch of a finger. Accordingly, the first force sensor  2200   a  may be used to detect a global or large-area deflection similar to the sensing configuration  2150  described above with respect to  FIGS. 21C-21D . 
       FIG. 22B  depicts a second force sensor  2200   b  that is configured to detect a local or small-area deflection of a top case  2204   b  having an input surface  2202   b . Similar to the previous example, the second force sensor  2200   b  may operate on a self-capacitive sensing scheme in which one or more electrodes  2220   b  of an electrode array may be used to detect a change in capacitance  2215   b  between a respective electrode  2220   b  and an object  2210   b  (e.g., a user&#39;s finger) applying a force to the input surface  2202   b . In an example embodiment, the top case  2204   b  is separated from the electrode  2220   b  by a compressible layer  2206   b , which may include a compressible medium or material similar to the example provided above with respect to  FIG. 22A . 
     As shown in  FIG. 22B , the top case  2204   b  may be formed from a material or materials that allow for localized deflection or deformation in response to a force applied by an object  2210   b , such as a user&#39;s finger. Example materials that may be used to form the top case  2204   b  may include glass, sapphire, polymer, metal, and/or composite materials that are configured to produce the corresponding locally deforming or deflecting structural response to an applied force. In some cases, the top case  2204   b  is formed from a laminate of materials in which each layer is allowed to slip or shear to provide a localized deformation in response to the touch of a finger. Accordingly, the second force sensor  2200   b  may be used to detect a localized or small-area deflection similar to the sensing configuration  2100  described above with respect to  FIGS. 21A-21B . 
       FIG. 22C  depicts a third force sensor  2200   c  that is configured to detect a global or large-area deflection of a top case  2204   c  having an input surface  2202   c . The third force sensor  2200   c  may operate on a mutual-capacitive sensing scheme in which one or more pairs of electrodes ( 2220   c ,  2222   c ) are used to detect a change in capacitance  2215   c  due to the presence of an object  2210   c  (e.g., a user&#39;s finger) applying a force to the input surface  2202   c . In an example embodiment, the top case  2204   c  is separated from the electrode pairs ( 2220   c ,  2222   c ) by a compressible layer  2206   c , which may include a compressible medium or material similar to the embodiments described above with respect to  FIGS. 22A-22B . 
     In the third force sensor  2200   c , the capacitance  2215   c  may change as a force applied by object  2210   c  depresses or displaces the top case  2204   c  toward the electrode pair ( 2220   c ,  2222   c ) thereby compressing the compressible layer  2206   c . The capacitance  2215   c  or charge coupling may be affected by the presence of the object  2210   c , which may steal or draw charge away from the electrode pair ( 2220   c ,  2222   c ). The change in the capacitance  2215   c  may correspond to a degree or amount of force applied, which may correspond to a predicable compressibility response or spring force of the compressible layer  2206   c . Force-sensing circuitry operably coupled to the third force sensor  2200   c  may be used to measure the change in capacitance  2215   c  (or accumulated charge or any other suitable phenomena) and produce a signal that corresponds to the amount or degree of force applied by the object  2210   c.    
     In some implementations, the top case  2204   c  may be substantially rigid or non-compliant over the localized region corresponding to the touch of the object  2210   c , similar to the example provided above with respect to  FIG. 22A . Accordingly, the third force sensor  2200   c  may be used to detect a global or large-area deflection similar to the force-sensing configuration  2150  described above with respect to  FIGS. 21C-21D . 
       FIG. 22D  depicts a fourth force sensor  2200   d  that is configured to detect a local or small-area deflection of a top case  2204   d  having an input surface  2202   d . Similar to the example of  FIG. 22C , the fourth force sensor  2200   d  may operate on a mutual-capacitive sensing scheme in which one or more pairs of electrodes  2220   d ,  2222   d  may be used to detect a change in capacitance  2215   d  due to the presence of the object  2210   d  (e.g., a user&#39;s finger) applying a force to the input surface  2202   d . In an example embodiment, the top case  2204   d  is separated from the electrode pairs ( 2220   d ,  2222   d ) by a compressible layer  2206   d , which may include a compressible medium or material similar to the embodiments described above with respect to  FIGS. 22A-22B . 
     As shown in  FIG. 22D , the top case  2204   d  may be formed from a material or materials that allow for localized deflection or deformation in response to a force applied by an object  2210   d , such as a user&#39;s finger, similar to the example provided above with respect to  FIG. 22B . Accordingly, the fourth force sensor  2200   d  may be used to detect a localized or small-area deflection similar to the sensing configuration  2100  described above with respect to  FIGS. 21A-21B . 
       FIGS. 22E-22F  depict example force sensors  2200   e  and  2200   f , respectively. Similar to the force sensors  2200   c  and  2200   d  of  FIGS. 22C and 22D , the force sensors  2200   e  and  2200   f  operate using a mutual-capacitive sensing scheme. In particular, the force sensor  2200   e  depicts a top case  2204   e  having an input surface  2202   e  that deflects globally or over a large area in response to a force applied by the object  2210   e . The applied force causes relative movement between a respective pair of electrodes  2220   e ,  2222   e , which are separated by compressible layer  2206   e . The relative movement between the pair of electrodes  2220   e ,  2222   e  or compression of the compressible layer  2206   e  results in a change in capacitance, which may be sensed using force-sensing circuitry operatively coupled to the pair of electrodes  2220   e ,  2222   e . Similar to the examples provided above with respect to  FIGS. 22A and 22C , the top case  2204   c  may be configured to resist or prevent localized deflection in response to the applied force. 
     The sixth force sensor  2200   f  of  FIG. 22F  operates in a similar fashion except that the top case  2204   f  having an input surface  2202   f  is configured to deflect locally in response to a force applied by the object  2210   f . A pair of electrodes  2220   f ,  2222   f  separated by a compressible layer  2206   f  deflect in response to the applied force resulting in a change in capacitance  2215   f , which may be sensed using force-sensing circuitry. Similar to the examples provided above with respect to  FIGS. 22B and 22D , the top case  2204   f  may be configured to deflect locally in response to the applied force. 
       FIG. 22G  depicts a seventh force sensor  2200   g  configured to detect an applied force using a strain-based sensing scheme. Specifically, the seventh force sensor  2200   g  is configured to detect the magnitude of an applied force using an array of strain-sensor elements  2230   g  operably coupled to the top case  2204   g  having an input surface  2202   g . As shown in  FIG. 22G , the top case  2204   g  may experience a localized deformation or deflection in response to a force applied by the object  2210   g  (e.g., a user&#39;s finger). The localized deformation or deflection may cause one or more of the strain-sensor elements  2230   g  to be placed into a strained condition, which may produce an electrical response (e.g., a change in resistance or impedance or any other suitable electrical phenomena) that can be measured using force-sensing circuitry. 
     In one example, the strain-sensor elements  2230   g  are formed from a strain-sensitive material that exhibits a change in resistance in response to a change in strain condition. Example strain-sensitive materials include, but are not limited to, indium tin oxide, indium gallium oxide, gallium zinc oxide, indium gallium zinc oxide, metal nanowire, nanotube, carbon nanotube, graphene, conductive polymers, a semiconductor material, a metal oxide material, copper, gold, constantan, karma, isoelastic, or any combination thereof. Depending on the specific composition and thickness of the strain-sensitive material, the strain-sensor elements  2230   g  may be either light-transmissive or opaque. 
     In some implementations, the strain-sensor elements  2230   g  are formed into a two-dimensional array across the area of the input surface  2202   g . Each strain-sensor element  2230   g  may form a pixel or element of the two-dimensional array and may include a strain gauge or similarly shaped strain-sensitive element. The strain gauge may include multiple traces or fingers that are configured to detect strain along a particular direction or multiple directions. If the strain-sensor elements  2230   g  are arranged in a two-dimensional array, the strain-sensor elements  2230   g  may be used to determine both the location and the magnitude of multiple forces applied to the input surface  2202   g . Some configurations may provide multi-touch, multi-force capability in which the magnitude of each applied force may be calculated or estimated. 
     With regard to the force sensor  2200   g  of  FIG. 22G , the strain-sensor elements  2230   g  may also include a temperature-compensating configuration or temperature-compensating elements to reduce the effect of changes in temperature on the force-measurements performed by the force sensor  2200   g . For example, the strain-sensor elements  2230   g  may include additional reference elements that are configured to provide an electrical response due to a change in temperature that can be used to calibrate or compensate for temperature effects on the force measurement. In some cases, the force sensor  2200   g  includes one or more strain break elements or strain relief features that can be used to isolate the strain-sensor elements  2230   g  from a temperature or reference element used to compensate for changes in temperature. 
       FIGS. 22H and 22J  depict example force sensors  2200   h  and  2200   j , respectively. The force sensors  2200   h  and  2200   j  depict example configurations in which the force sensors  2200   h  and  2200   j  are integrated with a mutual-capacitance sensor. In the eighth force sensor  2200   h  configuration of  FIG. 22H , an array of force-sense electrodes  2222   h  share a drive electrode layer  2220   h  with an array of touch-sense electrodes  2224   h . The drive electrode layer  2220   h  may include an array of drive electrodes that are arranged transverse to each of the force-sense electrodes  2222   h  and the touch-sense electrodes  2224   h . The drive electrode layer  2220   h  may be operatively coupled to force- and/or touch-sensing circuitry that is configured to detect changes in a first touch-sensitive capacitance  2216   h  and/or a second force-sensitive capacitance  2215   h . In some implementations, drive signals transmitted using the drive electrode layer  2220   h  may be time or frequency multiplexed to facilitate signal differentiation between changes in the touch-sensitive capacitance  2216   h  and the force-sensitive capacitance. In some implementations, the drive electrode layer  2220   h  forms an electrical shield or isolation layer between the force-sense electrodes  2222   h  and the touch-sense electrodes  2224   h  and/or other electrical components in the device. 
     Similar to the force sensors  2200   e  and  2200   f  of  FIGS. 22E and 22F , the force sensors  2200   h  and  2200   j  operate using a mutual-capacitive sensing scheme. In particular, the force sensor  2200   h  depicts a top case  2204   h  having an input surface  2202   h  that deflects globally or over a large area in response to a force applied by the object  2210   h . In some cases, the touch-sense electrodes  2224   h  and the drive electrode layer  2220   h  are separated by a substantially non-compressible layer or substrate that allows the applied force to be transferred and to compress a compressible layer  2206   h  positioned between the force-sense electrodes  2222   h  and the drive electrode layer  2220   h . The applied force causes relative movement between the drive electrode layer  2220   h  and the force-sense electrodes  2222   h . Similar to other mutual capacitance force sensors described above, the relative movement between the drive electrode layer  2220   h  and the force-sense electrodes  2222   h  or compression of the compressible layer  2206   h  results in a change in the force-sensitive capacitance  2215   h , which may be sensed using force-sensing circuitry operatively coupled to the force-sense electrodes  2222   h . Similar to the examples provided above with respect to  FIGS. 22A, 22C, and 22E , the top case  2204   h  may be configured to resist or prevent localized deflection in response to the applied force. 
     The ninth force sensor  2200   j  of  FIG. 22J  operates in a similar fashion except that the top case  2204   j  having an input surface  2202   j  is configured to deflect locally in response to a force applied by the object  2210   j . In this example, the touch-sense electrodes  2224   j  and the drive electrode layer  2220   j  may also deflect in response to the applied force. Here, the touch sense electrodes  2224   j  and the drive electrode layer  2220   j  are separated by a substantially non-compressible layer that is able to deflect when a force is applied by the object  2210   j . In general, the substantially non-compressible layer may maintain the distance between the touch sense electrodes  2224   j  and the drive electrode layer  2220   j  but also locally deform to allow for compression of a compressible layer  2206   j  positioned below the drive electrode layer  2220   j . The force-sense electrodes  2222   j  may be separated from the drive electrode layer  2220   j  by the compressible layer  2206   j , which is configured to deflect in response to the applied force resulting in a change in capacitance  2215   j , which may be sensed using force-sensing circuitry. Similar to the examples provided above with respect to  FIGS. 22B, 22D, and 22F , the top case  2204   j  may be configured to deflect locally in response to the applied force. 
     In the example of  FIG. 22J , the compressible layer  2206   j  includes an array of compressible column structures  2230   j  arranged over the area of the force sensor  2200   j . The compressible column structures  2230   j  may be formed from a compressible material, including elastomers, foams, or other similar material. In some implementations, the compressible column structures  2230   j  are formed from a silicone material. The compressible column structures  2230   j  may be surrounded by air, a gel, or a liquid material. In some cases, the gel or liquid material is optically index-matched to the material that forms the compressible column structures  2230   j . Thus, in some implementations, the compressible column structures  2230   j  are not visually perceptible. 
       FIG. 22K  depicts a tenth force sensor  2200   k  configured to detect an applied force using an optical sensing scheme. In particular, the force sensor  2200   k  depicts a top case  2204   k  having an input surface  2202   k  that deflects globally or over a large area in response to a force applied by the object  2210   k . The applied force causes relative movement between the top case  2204   k  and one or more optical sensors  2238   k . Similar to the examples provided above with respect to  FIGS. 22A, 22C, and 22E , the top case  2204   k  may be configured to resist or prevent localized deflection in response to the applied force. 
     The optical sensors  2238   k  may use any suitable optical distance sensing technology, such as time-of-flight sensing, interferometric sensing, intensity-based sensing, confocal sensing, or the like. Multiple optical sensors  2238   k  may be used, and they may be strategically located below the top case  2204   k  to facilitate force sensing due to deflection or displacement of the top case  2204   k . Also, while other force sensors may include a compressible layer between a top case and a force sensing layer (e.g., an electrode layer), the force sensor  2200   k  may have an optically transparent gap between the optical sensors  2238  and the top case  2204   k . For example, the space between the optical sensors  2238   k  and the top case  2204   k  may be an air gap. In some cases, an air gap may exist directly above an optical sensor  2238   k  and extending to an underside of the top case  2204   k , while other areas of the top case  2204   k  are in contact with a compressible layer. For example, a compressible layer may be positioned under substantially the entire area of the top case  2204   k , except holes or air columns that coincide with the optical sensors  2238   k  may be formed in the compressible layer to allow a direct optical path to the top case  2204   k.    
       FIGS. 22L and 22M  depict an eleventh force sensor  2200   m  that is configured to detect an applied force using sensing elements located in a foot or support of the device. In particular, the force sensor  2200   m  includes a force-sensing structure  2230   m  located in each of the feet or supports of the device. In the present example, the force-sensing structure  2230   m  is a capacitive sensor having a first capacitive element  2232   m  and a second capacitive element  2234   m  separated by a compressible element  2236   m . Similar to the capacitive force sensors described above with respect to other embodiments, an applied force causes the compressible element  2236   m  to compress or deflect, resulting in a reduction in the gap between the first capacitive element  2232   m  and the second capacitive element  2234   m . The relative movement between the first capacitive element  2232   m  and second capacitive element  2234   m  may be measured as a change in capacitance using force-sensing circuitry coupled to force-sensing structure  2230   m.    
       FIG. 22L  depicts the force sensor  2200   m  in an un-deflected state and  FIG. 22M  depicts the force sensor  2200   m  in a deflected or actuated state. As shown in  FIG. 22M , a force applied by object  2210   m  on the input surface  2202   m  causes compression of one or more of the force-sensing structures  2230   m , which may be detected by measuring a change in capacitance. Alternatively, the force-sensing structures  2230   m  may include one or more strain-sensitive elements that are configured to detect a small amount of compression caused by an applied force. The strain-sensitive elements may include a strain gauge, resistive sensor, or other similar element that exhibits a change in electrical response due to a deflection or strain. 
     As shown in  FIG. 22M , the force applied by the object  2210   m  may cause a non-uniform or unbalanced deflection or compression between each of the force-sensing structures  2230   m . For example, the force-sensing structures  2230   m  that are closest to an applied force may experience the greatest deflection or compression. As shown in  FIG. 22M , because the object  2210   m  is closest to the force-sensing structure  2230   m  on the right-hand side of the device, the compressible element  2236   m  of that force-sensing structure  2230   m  will experience a greater compression as compared to a force-sensing structure  2230   m  located on the left-hand side of the device. 
     The non-uniform or unbalanced compression of the force-sensing structures  2230   m  may be used to approximate the location of the object  2210   m  along the input surface  2202   m . By way of example, the displacement or compression of the force-sensing structures  2230   m  may be compared using a ratio of the amount of compression, which may be used to estimate the location of the object  2210   m  as a percentage or fraction of the distance between the force-sensing structures  2230   m . In some cases, a centroid may be computed using the relative output of two or more force-sensing structures  2230   m , which may be used to estimate the location of the object  2210   m  applying the force to the input surface  2202   m . Generally, three or more force-sensing structures  2230   m  would be necessary in order to provide an estimate of the two-dimensional location of the object  2210   m  along an input surface  2202   m  of the top case. 
     In some embodiments, an average or composite of the outputs of all of the force-sensing structures  2230   m  is used to compute a general or overall force applied to the input surface  2202   m . The average or composite of the outputs of the force-sensing structures may be used as a user input (e.g., an item selection). Additionally or alternatively, the general or overall applied force may be used to establish a baseline, calibration, or static input and used to cancel the effects of a user&#39;s wrist or other object that is resting or otherwise applying a force on the input surface  2202   m  or other portion of the device. Examples of palm rejection or other similar non-input user contact are described in more detail below with respect to  FIGS. 31A-31B . 
     With regard to the embodiments of  FIGS. 22A-22H and 22J -M discussed above, any of the electrodes or electrically conductive elements may be formed from a variety of conductive materials including, without limitation, indium tin oxide, indium gallium oxide, gallium zinc oxide, indium gallium zinc oxide, metal nanowire, nanotube, carbon nanotube, graphene, conductive polymers, a semiconductor material, a metal oxide material, copper, gold, constantan, karma, isoelastic, or any combination thereof. The conductive materials may be applied to the various layers or substrates of the force sensors using any one of a variety of manufacturing techniques including, for example, chemical vapor deposition (CVD), sputter deposition, printing, or other deposition technique. In some cases, the conductive materials are formed as a separate or distinct layer and applied or attached to a substrate or layer using an adhesive or other bonding technique. 
     The force sensors of  FIGS. 22A-22H and 22J-22M  are provided by way of example and are not intended to be limiting in nature. Actual implementations of the examples provided above may vary depending on the structural aspects and components of the device. Additionally, many of the force sensor embodiments described above with respect to  FIGS. 22A-22H and 22J-22M  may be combined to produce a composite or combination force sensor. For example, one or more of the capacitive-based force sensors described with respect to  FIGS. 22A-22F, 22H , and  22 J may be combined with one or more strain-based force sensors as described with respect to  FIG. 22G . 
       FIG. 23  depicts an example top case having an example force sensor positioned around a perimeter of the top case. More specifically,  FIG. 23  depicts a base portion  2300  having a top case  2310  coupled a bottom case  2320  to form an enclosed volume. The base portion  2300  of  FIG. 23  may correspond to any one of the base portions described herein. In particular, while not shown in this figure, the base portion  2300  may include a keyboard, one or more touch-input surfaces, and other components or elements described herein with respect to other embodiments. 
     As shown in  FIG. 23 , the base portion  2300  includes a force sensor  2330  positioned along the perimeter of the top case  2310 . The force sensor  2330  may be positioned between the top case  2310  and the bottom case  2320  and may be configured to measure an applied force by detecting a compression or relative displacement between the two components. As described below with respect to  FIGS. 24A-24B , the force sensor  2330  may include a compressible element or compressible layer that deflects in response to an applied force. The amount of deflection may be measured using one of more of the force-sensing schemes described above with respect to  FIGS. 24A-24B  and may be used to estimate the amount of force applied to a region or regions of the top case  2310 . 
     In some implementations, the top case  2310  is substantially rigid to facilitate force sensing using the perimeter force sensor  2330 . For example, the top case  2310  may be stiffened using a laminate or composite construction to facilitate transfer of a force along an input surface of the top case  2310  to the force sensor  2330  without allowing the top case  2310  to bend or deflect enough to contact an internal component that may interfere with the measurement performed by the force sensor  2330 . The top case may include one or more ribs, stiffeners or other structural features to provide the stiffness required for operation of the perimeter force sensor  2330 . Example stiffening techniques are described in more detail with respect to  FIGS. 8A-10 and 19A-20C . 
     In some implementations, the force sensor  2330  forms a seal between the top case  2310  and the bottom case  2320 . For example, the force sensor  2330  may be formed from a compliant material that is both compressible in response to an applied force and also compliant enough to form a barrier or seal to prevent the ingress of foreign matter into the internal volume defined by the top case  2310  and bottom case  2320 . In some cases, the force sensor  2330  is attached to the top case  2310  and bottom case  2320  using an adhesive and forms a waterproof or water-resistant seal between the two components. 
       FIGS. 24A and 24B  depict cross-sectional views of the top case and force sensor of  FIG. 23 . Specifically,  FIG. 24A  depicts an unactuated state of the top case  2310  in which the force sensor  2330  is uncompressed and  FIG. 24B  depicts an actuated state of the top case  2310  in which the force sensor  2330  is at least partially compressed in response to an applied force. The force may be applied by an object  2410  (e.g., a user&#39;s finger). The force sensor  2330  may either deform locally or globally (e.g., substantially uniformly) in response to the applied force. 
     Similar to the examples provided above with respect to  FIGS. 22A-22H and 22J , the force sensor  2330  may include a compressible layer or compressible element  2436  that compresses in response to the applied force. The amount of deflection of the compressible element  2436  may be measured by electrodes  2432 ,  2434  positioned on opposite sides of the compressible element  2436 . The force sensor  2330  may be operatively coupled to force-sensing circuitry that is configured to measure a change in an electrical response due to the deflection. In one example, the force-sensing circuitry is configured to measure a change in capacitance between the electrodes  2432  and  2434  caused by the deflection or compression of the compressible element  2436 . In another example, the force-sensing circuitry is configured to measure a change in charge or resistance between the electrodes  2432  and  2434  due to a compression of the compressible element  2436 , which may be formed from a piezoelectric or piezoresistive material. 
     In some implementations, the force sensor  2330  may be formed from a series or array of electrode pairs that are configured to detect the amount of deformation over a respective region or area. Similar to the description above with respect to  FIG. 22J , the location of the force applied by the object  2410  may result in a non-uniform or unbalanced deflection between electrode pairs of the force sensor  2330 , which may be used to estimate a location of an applied force and/or the magnitude of multiple forces on the top case  2310 . In particular, a relative measurement (e.g., a ratio) of the compression of two or more electrode pairs of the force sensor  2330  may be used to estimate the location of the object  2410  as a percentage or fraction of the distance between the respective two or more electrode pairs. In some cases, a centroid may be computed using the relative output of two or more electrode pairs, which may be used to estimate the location of the object  2410  applying the force. 
     In some embodiments, an average or composite of multiple electrode pairs of the force sensor  2330  may be used to compute a general or overall force applied to the input surface  2202   h  ( FIG. 22H ). The average or composite of the outputs of the force-sensing structures may be used as a user input (e.g., an item selection). Additionally or alternatively, the general or overall applied force may be used to establish a baseline, calibration, or static input and used to cancel the effects of a user&#39;s wrist or other object that is resting or otherwise applying a force to the top case  2310 . Examples of palm rejection or other similar non-input user contact are described in more detail below with respect to  FIGS. 31A-31B . 
       FIG. 25  depicts an exploded view of a top case having an example two-layer force sensor. In particular,  FIG. 25  depicts an example base portion  2500  having a top case  2510  coupled to a bottom case  2520  to form an enclosed volume. The base portion  2500  of  FIG. 25  may correspond to any one of the base portions described herein. In particular, while not shown in this figure, the base portion  2500  may include a keyboard, one or more touch-input surfaces, and other components or elements described herein with respect to other embodiments. In accordance with some embodiments, the top case  2510  may include one or more recesses or a well  2512  formed into the top surface, which may receive components of a keyboard or other elements of the device. 
     As shown in  FIG. 25 , a force sensor  2530 , having a first sensing layer  2532 , a compressible layer  2536 , and a second sensing layer  2534 , may be coupled or attached to the top case  2510 . In some cases, the force sensor  2530  is a flexible laminate and attached to a lower surface of the top case  2510 . The flexibility of the force sensor  2530  may allow the force sensor  2530  to comply or conform to the geometry of the top case  2510 . In some instances, the force sensor  2530  is formed having a geometry that corresponds to the geometry of the top case  2510 . Thus, in the current example, the force sensor  2530  may have a pocket or well that corresponds to the well  2512  of the top case  2510 . 
     Each or both of the layers  2532  and  2534  may include an array of electrodes that are arranged over the area of the force sensor  2530 . The layers  2532  and  2534  are positioned on opposite sides of the compressible layer  2536 , which may be formed from a single sheet or, alternatively, multiple compressible elements arranged over the area of the force sensor  2530 . The compressible layer  2536  may include, without limitation, elastomers, gels, foams, air, compressible columns, or a combination thereof. 
     Similar to the examples described above with respect to  FIGS. 22A-22H and 22J , a force applied to the top case  2510  may be measured by measuring the relative compression between the electrodes of layers  2532  and  2534 . The force sensor  2530  may operate in accordance with a self-capacitance scheme, a mutual-capacitance scheme, a strain-based (e.g., piezo) sensing scheme, or any other force sensing schemes described herein. The force sensor  2530  may also be configured to detect a localized or global deflection between the layers  2532  and  2534 , depending on the flexibility or compliance of the top case  2510  and/or the elements of the force sensor  2530 . In some cases, the force sensor  2530  may be configured to deform locally or over a small area for certain predefined regions and configured to deform globally or over a large area for other predefined regions. 
       FIGS. 26A-26B  depict an example device having a haptic actuator. In particular,  FIGS. 26A-26B  depict a device  2600  having a haptic device  2610  coupled to the top case  2620  of a base portion  2622 . The haptic device  2610  is configured to produce a haptic output that may include movement (e.g., vibration or displacement) of the top case  2620 . The movement caused by the haptic device  2610  may be perceptible as tactile feedback to the user when the user is in contact with the top case  2620  or other portion of the device  2600 . In some instances, the haptic device  2610  may create a vibration or sound that is perceptible, even when the user is not in contact with the top case  2620 . 
       FIG. 26B  depicts a cross-sectional view of the device  2600  of  FIG. 26A  along section K-K in  FIG. 26A . In particular,  FIG. 26B  depicts a simplified schematic of the haptic device  2610  coupled to the top case  2620 . The haptic device  2610  may be configured to produce one or more types of motion. As shown in  FIG. 26B , the haptic device  2610  may be configured to produce lateral or side-to-side motion, as indicated by the horizontal arrows. Additionally or alternatively, the haptic device  2610  may be configured to produce a normal or planar movement, as indicated by the vertical arrows. Example hardware implementations of the haptic device  2610  are described below with respect to  FIGS. 29A-29H and 29J-29K . 
     The haptic device  2610  is configured to provide a general and/or local haptic output to the user for a variety of use cases. For example, the haptic device  2610  may provide a general haptic output in the form of a vibration to the exterior surface of the device (via the top case  2620 ) to notify the user of an event or action. The alert may correspond to any one of a variety of notifications including, for example, a notification that a message has been received, a phone call is incoming, a calendar reminder has been triggered, or that an event has been initiated/completed. The alert may also correspond to a system level event generated by the operating system or a hardware component integrated within the device. For example, the alert may correspond to a signal indicating that the device has been plugged in (outlet power has been coupled to a port of the device), the device has been coupled to an internet connection, the device is in a low-power state, the device is fully charged, and so on. Global haptics may also be used to indicate that an input has been received or triggered. For example, a global haptic output may be used to indicate that a touch force of a virtual button or key has exceeded a threshold resulting in an actuation of the virtual button or key, or that a touch force within a trackpad region has exceeded a threshold resulting in a “click” event. 
     The haptic device  2610  may also provide a local haptic output in the form of a localized deflection or movement to provide tactile feedback to a user. In some implementations, a local haptic output may be produced in response to user-touch input to indicate that an input has been received or triggered. For example, a local haptic output may be used to indicate that a touch input has been detected or registered on a first key (e.g., by a touch sensing system) or to indicate that a touch force of a virtual button or key has exceeded a threshold resulting in an actuation of the virtual button or key (e.g., as detected by a force sensing system). Similarly, a local haptic output may be used to indicate that a touch force within a trackpad region has exceeded a threshold resulting in a “click” event. A local haptic output may also be used to guide a user&#39;s touch along an input surface of the top case  2620  to indicate a tactile fiducial. For example, a local haptic output may be used to indicate the location of a virtual key (e.g., the “F” or “J” on a QWERTY keyboard). 
       FIGS. 27A-27D and 28A-28B  depict example haptic outputs that can be generated using a haptic device (e.g., haptic device  2610  of  FIGS. 26A-26B ).  FIGS. 27A-27D  depict a type of haptic output generated by moving or translating an exterior surface of the device. The movement may be performed globally or over a large area or region of the exterior surface. In contrast,  FIGS. 28A-28B  depict a type of haptic output generated using a localized deflection or deformation of the exterior surface of the device. The haptic outputs may be produced using the example haptic device  2610  discussed above with respect to  FIGS. 26A-26B  or with one or more of the other example haptic devices described below with respect to  FIGS. 29A-29H and 29J-29K and 30A-30B . 
       FIGS. 27A-27D  depict example global or large-area movements that may be produced using a haptic device. More specifically,  FIGS. 27A-27B  depict a contact surface  2702   a  that is configured to produce side-to-side or lateral movement ( 2720   a ,  2720   b ), as indicated by the horizontal arrows. The contact surface  2702   a  may correspond to the input surface or input region of a top case discussed with respect to other embodiments described herein. The lateral movement ( 2720   a ,  2720   b ) of the contact surface  2702   a  may produce a tactile or perceptible feedback when a body of a user  2710   a  is in contact with the contact surface  2702   a.    
     With regard to the embodiments of  FIGS. 27A-27B , friction between contact surface  2702   a  and the user  2710   a  may slightly pull or drag against the skin of the user, which is perceived as a tactile input by the user  2710   a . In some implementations, the amount of movement and/or the surface finish of the contact surface  2702   a  may be configured to produce a particular type of tactile feedback. For example, the surface finish of a glass or composite layer forming the contact surface  2702   a  may have a roughness or texture that is configured to produce a particular tactile feedback when the haptic output is actuated. 
       FIGS. 27C-27D  depict a contact surface  2702   c  that is configured to produce perpendicular or normal movement ( 2720   c ,  2720   d ), as indicated by the vertical arrows. Similar to the previous example, the contact surface  2702   c  may correspond to the input surface or input region of a top case discussed with respect to other embodiments described herein. The normal movement ( 2720   c ,  2720   d ) of the contact surface  2702   c  may produce a tactile or perceptible feedback when a body of a user  2710   c  is in contact with the contact surface  2702   c.    
     With regard to the embodiments of  FIGS. 27C-27D , relative movement between contact surface  2702   c  and the user  2710   c  may create small changes in surface pressure, which is perceived as a tactile input by the user  2710   c . In some implementations, the amount of movement (e.g., outward displacement  2706  and/or inward displacement  2708 ), the speed of the movement, and/or the frequency of the movement (if periodic) of the contact surface  2702   c  may be configured to produce a particular type of tactile feedback. For example, characteristics of the haptic device and/or the structural constraints on the contact surface  2702   c  may be configured to produce a particular tactile feedback when the haptic output is actuated. The structural constraints may include, for example, the boundary conditions on the contact surface  2702   c , the flexibility or stiffness of the layer or layers forming the contact surface  2702   c , and/or the presence of any stiffening components coupled to the contact surface  2702   c.    
       FIGS. 28A-28B  depict other example haptic outputs that can be generated using a haptic device (e.g., haptic device  2610  of  FIGS. 26A-26B ). More specifically,  FIGS. 28A-28B  depict a haptic output generated by moving, deforming, or translating a localized region or area of an exterior surface of the device. The haptic outputs may be produced using the example haptic device  2610  discussed above with respect to  FIGS. 26A-26B  or with one or more of the other example haptic devices described below with respect to  FIGS. 29A-28H, 29J-29K, and 30A-30B . 
       FIGS. 28A-28B  depict example localized or small-area movements that may be produced using a haptic device. More specifically,  FIGS. 28A-28B  depict example haptic output that results in a localized displacement or deformation of the contact surface  2802 . Localized haptic outputs may be configured to be primarily noticed by a user in a single area of a contact surface, and not significantly noticeable at other areas of the contact surface. In particular, the magnitude of a localized haptic output may be greater at one location than at another adjacent location. Thus, if a localized haptic output is produced on a contact surface in a region that corresponds to a key of a keyboard, the magnitude of the haptic output may be greater within the key region than at an adjacent key region. The magnitude of a haptic output may refer to the deformation or deflection of a contact surface (e.g., the physical distance that a portion of the contact surface moves), or it may refer to the perceived strength of the haptic output by a user. Such localized haptic actuators and haptic outputs may be used to provide a sensation that is similar to or otherwise evokes the feeling of using a mechanical keyboard. For example, when a key input is registered, instead of the entire input surface being subjected to a substantially uniform haptic output, only a localized region associated with the key (which may be as small as a single key) may be subjected to a haptic output. Thus, other fingers that may be resting on or touching the input surface may not detect any haptic output (or as significant of a haptic output) as the finger that selected the key. This may also provide a positive feedback to the user as to which key was selected. 
     As shown in  FIG. 28A , a region or localized area of the contact surface  2802  may be displaced or deformed outwardly to produce a momentarily raised region  2806 . Similarly, as shown in  FIG. 28B , a region or localized area of the contact surface  2802  may be displaced or deformed inwardly to produce a momentarily depressed or recessed region  2808 . Depending on the implementation, the haptic output may include an outward displacement, an inward displacement, or both an inward and an outward displacement. The displacement may extend over any suitable area of an input surface. For example, in some cases a haptic actuator is configured to produce displacements that are aligned with and have substantially the same size as the key regions of a keyboard. Thus, distinct localized displacements, such as those shown in  FIGS. 28A-28B  may be produced for each key of a keyboard (e.g., the virtual keys of a virtual keyboard). In some cases, the displacements are slightly larger than an individual key, and in some cases a haptic actuator is configured to produce displacements that provide haptic outputs to multiple key regions of a keyboard. Any of the haptic actuators described herein may be configured to produce localized haptic outputs and/or displacements at any particular localized region of an input surface or top case. For example, piezoelectric actuators may be positioned below or near individual key regions of a keyboard to act as the haptic actuator for that particular key region. In some cases, a single piezoelectric actuator may provide haptic outputs to two, three, four, five, six, or more keys (but less than all of the keys of a keyboard). 
     With regard to the embodiments of  FIGS. 28A-28B , relative movement between contact surface  2802  and the body of the user  2810  (e.g., the user&#39;s finger) may create small changes in surface pressure, which may be perceived as a tactile input by the user  2810 . In some implementations, the amount of movement (e.g. outward displacement  2806  and/or inward displacement  2808 ), the speed of the movement, and/or the frequency of the movement (if periodic) of the contact surface  2802  may be configured to produce a particular type of tactile feedback. For example, characteristics of the haptic device and/or the flexibility the contact surface  2802  may be configured to produce a particular tactile feedback when the haptic output is actuated. The flexibility of the contact surface  2802  may be driven by the structural configuration and/or constraints of the layer or layers forming the contact surface  2802 . 
       FIGS. 29A-29H and 29J-29K  depict example haptic devices that can be used to produce one or more of the haptic outputs described above with respect to  FIGS. 27A-27D and 28A-28B . The following haptic devices are provided by way of illustrative example and are not intended to be limiting. In some implementations, a portable computing device (also referred to as a portable computer) may include more than one haptic device and possibly more than one type of haptic device. Each haptic device may be configured to produce a certain type of haptic output over different regions or overlapping regions of an exterior surface of a portable computer or other portable electronic device. 
       FIG. 29A  depicts an example haptic device  2900   a  that may be used to impart an in-plane force (relative to a plane defined by the contact surface) to the contact surface  2902   a , thereby displacing or moving the contact surface  2902   a  in a lateral or side-to-side (e.g., in-plane) motion, as indicated by the arrows. In the present implementation, the haptic device  2900   a  includes an electromagnetic actuator having an electromagnetic element  2910   a  that is magnetically coupled to a magnet or attractor plate  2912   a . The electromagnetic element  2910   a  may be driven by an electrical current or electrical signal, which may generate a magnetic field that attracts or repels the attractor plate  2912   a . The magnetic coupling between the electromagnetic element  2910   a  and the attractor plate  2912   a  results in the lateral or side-to-side motion of the contact surface  2902   a . The electrical current or electrical signal may be periodic or alternating, which results in periodic or oscillatory movement of the contact surface  2902   a . The haptic device  2900   a  may be driven to produce an impulse movement, series of impulse movements, and/or a vibration of the contact surface  2902   a.    
       FIG. 29B  depicts another example haptic device  2900   b  that may be used to displace or move the contact surface  2902   b . Similar to the previous example, the haptic device  2900   b  includes an electromagnetic actuator having an electromagnetic element  2910   b  that is magnetically coupled to a magnet or attractor plate  2912   b . The electromagnetic element  2910   b  may be driven by an electrical current or electrical signal resulting in a magnetic field that attracts or repels the attractor plate  2912   b . The magnetic coupling between the electromagnetic element  2910   b  and the attractor plate  2912   b  may be configured to impart an out-of-plane force (relative to a plane defined by the contact surface) to the contact surface  2902   b , thereby producing a normal or perpendicular (or out-of-plane) movement of the contact surface  2902   b . The electrical current or electrical signal may be periodic or alternating, which results in periodic or oscillatory movement of the contact surface  2902   b . Thus, similar to the example described above, the haptic device  2900   b  may be driven to produce an impulse movement, series of impulse movements, and/or a vibration of the contact surface  2902   b.    
     The haptic devices  2900   a  and  2900   b  of  FIGS. 29A and 29B , respectively, may be used to generate either a global (e.g., large-area) or local (e.g., small-area) haptic output along a contact surface. For example, the haptic device  2900   a  may be used to induce lateral motion over an entire contact surface or a large area of the contact surface  2902   a  if the haptic device  2900   a  is coupled to a substantially rigid or stiff layer that forms the contact surface  2902   a . The haptic device  2900   a  may also be configured to induce lateral motion over a localized or small area of the contact surface  2902   a  if the layer or layers that form the contact surface  2902   a  are allowed to deflect or displace with respect to the larger surface. The localized deflection may be provided by a strain relief or flexible feature integrally formed within or coupled to the layer or layers that define the contact surface  2902   a . Similarly, the haptic device  2900   b  may be configured to produce a global or localized haptic output depending on the structural constraints of the system that may allow or prevent localized displacement or movement of the contact surface  2902   b.    
       FIGS. 29C and 29D  depict other example haptic devices  2900   c  and  2900   d . The haptic devices  2900   c  and  2900   d  may be configured to produce a localized deflection or displacement of the contact surfaces ( 2902   c ,  2902   d ) using an actuator strip ( 2910   c ,  2910   d ), which may be formed from a piezoelectric material. Force spreading layers  2909   c ,  2909   d  may be disposed between the actuator strips  2910   c ,  2910   d  and the contact surfaces  2902   c ,  2902   d . The force spreading layers  2909   c ,  2909   d  may increase the area of influence of the actuator strips  2910   c ,  2910   d . More particularly, the force spreading layers  2909   c ,  2909   d  may increase the area of the contact surfaces  2902   c ,  2902   d  on which the motions, deflections, or vibrations produced by the actuator strips  2910   c ,  2910   d  is detectable by a user (e.g., a user&#39;s finger). The force spreading layers  2909   c ,  2909   d  may be formed from or include any suitable material, such as silicone, metal, glass, elastomeric materials, polymers, or the like. 
     In the implementation depicted in  FIG. 29C , a voltage may be applied across the piezoelectric material of the actuator strip  2910   c  causing the actuator strip  2910   c  to shrink or reduce in length. If the actuator strip  2910   c  is not allowed to shear with respect to the layer forming the contact surface  2902   c , the change in length may produce a momentarily raised or protruding region  2908   c . The localized deformation may also be characterized as convex or proud of the contact surface  2902   c.    
     In the implementation depicted in  FIG. 29D , a voltage may be applied across the piezoelectric material of the actuator strip  2910   d  causing the actuator strip  2910   d  to grow or increase in length. Similar to the previous example, if the actuator strip  2910   d  is not allowed to shear with respect to the layer forming the contact surface  2902   d , the change in length may produce a momentarily depressed or recessed region  2908   d . The localized deformation may also be characterized as concave or recessed with respect to the contact surface  2902   d . As described above with respect to  FIGS. 28A-28B , above, a localized deflection or deformation of a contact surface may be tactically perceived by a user in contact with a corresponding region of the contact surface. 
     In the examples depicted in  FIGS. 29C-29D , the haptic devices  2900   c  and  2900   d  may be configured to cause local deflections and/or deformations that are substantially isolated to or contained within an area of a key region. For example, in the case of a device with a glass surface that defines non-mechanical keys (e.g., virtual keys or key regions that are displayed by an underlying display, or that are defined by a mask, paint, ink, or dye on the glass surface), each key may be associated with a haptic device similar to the haptic devices  2900   c ,  2900   d . In such cases, each key, or at least a subset of the keys, may be associated with a distinct haptic actuator that produces a haptic output designed to be felt by a user only within that key region. Moreover, the key-specific haptic actuators may be configured to produce a haptic output for its associated key in response to a touch and/or force sensor detecting a key input applied to the corresponding key. Accordingly, distinct haptic outputs may be produced for each key region, which may mimic or suggest the sensation of typing on a mechanical keyboard, in which a key strike on one key produces a tactile feel that is primarily and/or substantially felt only at the key being struck. 
       FIG. 29E  depicts another example haptic device  2900   e  that may be used to displace or move the contact surface  2902   e  or otherwise produce a tactile output via the contact surface  2902   e . The haptic device  2900   e  may include a mass  2916   e  coupled to a housing  2914   e  (or other structure) via spring members  2918   e . The spring members  2918   e  are shown as coil springs, but other spring types and/or resilient members may be used (e.g., foams, disc springs, torsion springs, elastomer bumpers, etc.). The haptic device  2900   e  also includes an electromagnetic actuator configured to oscillate or otherwise move the mass  2916   e  relative to the housing  2914   e , thereby imparting an impulse movement, a series of impulse movements, and/or a vibration to the contact surface  2902   e . The electromagnetic actuator may move the mass  2916   e  in a direction that is substantially parallel to a plane defined by the contact surface  2902   e . The electromagnetic actuator may be incorporated with the haptic device  2900   e  in any suitable manner, and may include magnets, ferromagnetic materials, electromagnetic coils, and the like. For example, the mass  2916   e  may be or may include a magnet, and a coil may be wrapped around the mass  2916   e  or positioned next to the mass  2916   e , thus allowing the coil and the magnet to influence one another to produce motion and thus haptic output. While  FIG. 29E  shows the housing  2914   e  attached to the contact surface  2902   e , it may be attached to another component within a device, and the impulse(s) and/or vibrations may be detectable by a user via the contact surface  2902   e  via the physical path between the mounting location and the contact surface  2902   e.    
       FIG. 29F  depicts another example haptic device  2900   f  that may be used to displace or move the contact surface  2902   f  or otherwise produce a tactile output via the contact surface  2902   f . The haptic device  2900   f  may include a housing  2920   f , a mass  2924   f , and an electromagnetic actuator  2926   f  (e.g., a voice coil motor or any other suitable actuator) that is configured to move the mass  2924   f  relative to the housing  2920   f  (or other structure) and/or the contact surface  2902   f . The electromagnetic actuator  2926   f  may be configured to move the mass  2924   f  in a direction substantially perpendicular to a plane defined by the contact surface  2902   f.    
     The haptic device  2900   f  also includes a spring member  2922   f  contacting the mass  2924   f  and the contact surface  2902   f . The spring member  2922   f  is shown as a coil spring, but other spring types and/or resilient members may be used (e.g., foams, disc springs, torsion springs, elastomer bumpers, etc.). The spring member  2922   f  may impart an impulse movement, a series of impulse movements, and/or a vibration to the contact surface  2902   f , thereby producing a tactile output. The tactile output from a single haptic device  2900   f  may be detectable by a user at substantially any location along the contact surface (e.g., anywhere on a top case of a device), or it may be detectable substantially only locally. In the latter case, multiple haptic devices  2900   f  may be incorporated with a device to provide local haptic outputs via the contact surface  2902   f.    
       FIG. 29G  depicts another example haptic device  2900   g  that may be used to displace or move the contact surface  2902   g  or otherwise produce a tactile output via the contact surface  2902   g . The haptic device  2900   g  may be configured to produce a localized deflection or displacement of the contact surface, similar to the haptic devices  2900   c ,  2900   d , using an actuator strip  2934   g , which may be formed from a piezoelectric material. The actuator strip  2934   g  may be attached to a beam  2930   g  that is in turn coupled to the contact surface  2902   g  via a force spreading layer  2932   g . The beam  2930   g  may amplify the displacement of the actuator strip  2934   g , and/or convert the deflection of the actuator strip  2934   g  to a directional motion that produces a more detectable haptic output than would the actuator strip  2934   g  alone. The haptic device  2900   g  may also include a force spreading layer  2932   g  between the beam  2930   g  and the contact surface  2902   g , which may increase the area of influence of the beam  2930   g . More particularly, the force spreading layer  2932   g  may increase the area of the contact surface  2902   g  on which the motions, deflections, or vibrations produced by the actuator strip  2934   g  and/or beam  2930   g  are detectable by a user (e.g., a user&#39;s finger). The force spreading layer  2932   g  may be formed from or include any suitable material, such as silicone, metal, glass, elastomeric materials, polymers, or the like. 
       FIG. 29H  depicts another example haptic device  2900   h  that may be used to displace or move the contact surface  2902   h  or otherwise produce a tactile output via the contact surface  2902   h . The haptic device  2900   h  may be substantially similar to the haptic device  2900   g , but instead of the beam  2930   g  being having a free end (e.g., having a cantilevered configuration), the beam  2930   h  may be attached to the top case at multiple locations (e.g., at two opposite ends). In some cases, the beam  2930   h  may resemble a plate with a recess that is defined by walls around the entire periphery of the recess. In other respects, the haptic device  2900   h  may be the same as or similar to the haptic device  2900   g , and may include an actuator strip  2934   h  and a force spreading layer  2932   h  which may be the same as or similar to the corresponding components in  FIG. 29G . 
       FIGS. 29J and 29K  illustrate another example haptic device  2900   j  that may be used to displace or move a contact surface or otherwise produce a tactile output via the contact surface.  FIG. 29J  shows a partial top view of a contact surface  2940 , which may correspond to a top case of a computing device, as described herein.  FIG. 29K  shows a partial cross-sectional view of the haptic device  2900   j , viewed along section H-H in  FIG. 29J . An opening or slit  2944  may be formed in the contact surface  2940  to define a beam  2942  (or other cantilevered or flexible member). As shown in  FIG. 29K , an actuator strip  2950  (which may be similar to the actuator strips  2909   c ,  2909   d , above, and may be formed from or include a piezoelectric material) may be coupled to the contact surface  2940  via a force spreading layer  2948  (which may be the same as or similar to the force spreading layers  2909   c ,  2909   d , above). When the actuator strip  2950  is actuated, it may cause the beam  2942  to deflect upwards (as shown) or downwards to produce a localized deformation that can be detected by a user (e.g., by a user&#39;s finger).  FIG. 29K  also shows an optional cover  2946  which may overlie at least the beam  2942  (and optionally an entire top case or keyboard region) to prevent dust, liquid, and/or other debris or contaminants from entering the device through the slit  2944 . The cover  2946  may be any suitable material, such as a polymer film, and may be adhered to or otherwise secured to the contact surface  2940 . In some cases, such as where no cover  2946  is used, the slit  2944  is sufficiently small to substantially prevent contaminants from entering the device absent additional external forces, pressures, or the like (e.g., outside of normal operating conditions for a typical computing device such as a notebook computer). 
     In a given implementation, one or more of the haptic devices of  FIGS. 29A-29H and 29J-29K  may be arranged with respect to a top case of a portable computer or other electronic device. The arrangement of the haptic devices may enable different haptic feedback over different portions of the top case. For example, haptic devices that are configured to produce small, localized deformations and/or haptic outputs may be used to produce haptic outputs that are detectable on individual key regions of a keyboard. This may include positioning one haptic actuator at or below each of at least a subset of key regions of a keyboard, and/or assigning a single haptic actuator to a small group of keys or key regions (e.g., one haptic actuator for a group of two, three, four, five, six, or seven keys). In addition, haptic devices that are configured to produce larger scale deformations and/or deflections of an input surface may be used to provide other types of feedback other than or in addition to key press feedback.  FIG. 30A  depicts an example arrangement of different haptic devices over a contact surface of an example top case of a device, including devices that produce localized haptic outputs and devices that produce more global haptic outputs. The contact surface of the top case shown and described with respect to  FIG. 30A  may correspond to the input surface described above with respect to other embodiments. 
     As shown in  FIG. 30A , the device  3000   a  may include multiple electromagnetic actuators  3022 ,  3024 ,  3026 ,  3028  arranged along regions of the top case that are adjacent a keyboard region  3030   a . The electromagnetic actuators  3022 ,  3024 ,  3026 ,  3028  may include more than one type of actuator, each type configured to produce a different type of haptic feedback in response to a different event or action. 
     The electromagnetic actuators  3022 ,  3024  may be a first type of haptic device configured to produce a first type of haptic output. For example, the electromagnetic actuators  3022 ,  3024 , positioned within a trackpad region (shown in front of the keyboard region  3030   a  as shown in  FIG. 30A , but which also may include areas on the sides and along the back of the keyboard region  3030   a ), may be lateral-actuating haptic devices that are configured to produce a lateral or side-to-side (e.g., in-plane) movement of the top case  3004   a . The haptic output produced by the electromagnetic actuators  3022 ,  3024  may be detectable at any location in the trackpad region. 
     The electromagnetic actuators  3022 ,  3024  may be similar to the haptic devices described above with respect to  FIG. 29A  and/or  FIG. 29E . The electromagnetic actuators  3022 ,  3024  may be configured to produce a haptic output that simulates the mechanical actuation of a traditional trackpad. The haptic output may include an impulse or multiple impulses that simulate the actuation of a physical metal dome used in some traditional button devices. The haptic output of the electromagnetic actuators  3022 ,  3024  may be isolated from regions outside of the trackpad region  3020   a  using strain relief or flex regions  3034  that allow relative movement within the regions of the top case  3004   a.    
     The electromagnetic actuators  3026 ,  3028  may be a second type of haptic device configured to produce a second type of haptic output. For example, the electromagnetic actuators  3026 ,  3028 , positioned within auxiliary input regions (along the sides the keyboard region  3030   a ), may be surface-normal-actuating haptic devices that are configured to produce a perpendicular or surface-normal (e.g., out-of-plane) movement of the top case  3004   a . The electromagnetic actuators  3026 ,  3028  may be similar to the haptic devices described above with respect to  FIG. 29B  and/or  FIG. 29F . The electromagnetic actuators  3026 ,  3028  may be configured to produce a haptic output that provides a global or large-area vibration across the surface of the top case  3004   a.    
     As shown in  FIG. 30A  the device  3000   a  may also include multiple piezoelectric actuators  3032  arranged throughout the keyboard region  3030   a  of the top case  3004   a  to form a set of virtual keys. The multiple piezoelectric actuators  3032  may correspond to the haptic devices  2900   c ,  2900   d ,  2900   g ,  2900   h , and  2900   j  described above with respect to  FIGS. 29C, 29D, 29G, 29H, and 29J , respectively. The piezoelectric actuators  3032  may be arranged in locations that correspond to the position of keys of a traditional QWERTY keyboard and configured to produce a localized haptic feedback in response to the detection of a key-press on the surface of the top case  3004   a  within a virtual key within the keyboard region  3030   a . To help isolate or localize the haptic feedback to the area of the virtual key, the top case  3004   a  may include reliefs or flex regions  3034  between the virtual keys to provide some relative motion between the surface of each virtual key. In some cases, the flex regions  3034  are arranged along a direction that is substantially aligned with the length of piezoelectric actuator  3032  in order to facilitate local buckling of the virtual key. 
     While  FIG. 30A  shows an example device  3000   a  that includes multiple haptic actuators,  FIG. 30B  shows an example device  3000   b  that includes a single haptic actuator  3027 . The single haptic actuator  3027  may be configured to produce haptic outputs (e.g., in-plane and/or out-of-plane motions or impulses) to the top case  3004   b . In other respects, the device  3000   b  may include components similar to the device  3000   a , including for example the top case  3004   b  (which may exclude the flex regions  3034   a  shown in  FIG. 30A ), a keyboard region  3030   b , and a trackpad region  3020   b  on the top case  3004   b.    
       FIG. 30C  depicts an exploded view of part of a base portion  3000   c , showing a bottom case  3029  (which may be the same as or similar to any other bottom case described herein) and a top case  3004   c  that may be used in implementations where haptic actuators, such as any of the foregoing actuators, are included. The top case  3004   c  may be attached to the bottom case  3029  using multiple adhesives having different properties. For example, while some adhesives may provide a strong bond between the top case  3004   c  and the bottom case  3029 , they may not allow the top case  3004   c  to move relative to the bottom case  3029  a sufficient amount for haptic outputs to be sufficiently uniform across the entire top case. Thus, as shown in  FIG. 30C , different regions of an interface between the top case  3004   c  and the bottom case  3029  may use different adhesives. More particularly, a first adhesive  3036  may be applied to some portions of the interface, and a second, different adhesive  3038  may be applied to other portions of the interface. The different adhesives  3036 ,  3038  may have different properties, such as bond strength, rigidity, compliance, or the like. In some cases, the second adhesive  3038  is more compliant than the first adhesive. The locations and sizes of the regions having the first and second adhesives may be selected to produce a desired combination of bond strength and compliance between the top case  3004   c  and the bottom case  3029 , and may be different from the particular arrangement shown in  FIG. 30C . The use of multiple adhesives having different properties to facilitate a desired haptic response described with respect to  FIG. 30C  may also be applied to any of the techniques for joining a top case and a bottom case (and/or a display housing and a display component) described above with respect to  FIGS. 4A-6J . 
     The foregoing haptic devices and/or actuators are described as producing deformations, deflections, impulses, or other phenomena that are tactilely detectable by a user. In addition to such haptic and/or tactile outputs, haptic devices and actuators are also capable of producing audible outputs. For example, when a haptic device produces a haptic output, it may necessarily produce an audible output (e.g., corresponding to a fundamental frequency associated with the actuation of the haptic device and/or harmonic oscillations of the overall device). Additionally, haptic devices may be configured to produce audible outputs regardless of their haptic or tactile content. Such audible outputs may be produced at any time for any suitable reason or function. For example, haptic devices may be configured to produce audible outputs in conjunction with speakers or other audio output devices of an electronic device. The audio outputs that are produced by haptic devices may be triggered by, correspond to, or otherwise coordinate with the audio output produced by speakers. As a particular example, a haptic device may produce oscillations that substantially match at least a portion of a frequency spectrum that is being produced by a speaker. 
     Audio outputs and haptic outputs may be produced by a haptic device substantially simultaneously. For example, when a haptic output is generated by a haptic device (e.g., by oscillating the haptic device at a first frequency), an audible output may also be generated by the haptic device (e.g., by overlaying a second frequency on the signal being applied to the haptic device). The audible output may be functionally related or unrelated to the haptic output. For example, in some cases the audible output is designed to accompany the haptic output (e.g., so that a key press on a virtual key both feels and sounds like a key press of a conventional mechanical key). In other cases, the audible output may be unrelated, such as when a haptic output is being generated while the haptic device is producing audio that corresponds to active music playback. Moreover, as noted above, audible outputs from haptic devices may be produced independently of any haptic outputs (e.g., the haptic device may be used to produce audible outputs even when no haptic outputs are being produced). 
     Touch sensors of an integrated interface system as described herein may detect whether a user is touching a surface, such as a key or a trackpad region, but may not be capable of differentiating between light touches and more forceful touches. Force sensors enable a device to differentiate between such inputs. For example, force sensors, such as those described above with respect to  FIGS. 21A-22J , may be used to determine whether a touch input applied to a touch-input region is a gesture input (e.g., a swipe) or a “click” type of input (which may correspond to a key input or a trackpad input). 
     Where force sensors are used in regions of a computing device where only fingers are typically applied, such as a small trackpad adjacent a keyboard on a notebook computer, the maximum amount of force that is typically applied to the trackpad during normal use may be at or near the amount of force applied by a finger during a click event. For example, the highest force experienced by a trackpad is typically near the force applied by a finger during a selection (e.g., a click) applied to the trackpad. On the other hand, where a larger force sensitive region is used, such as the non-keyboard region of an integrated interface system as described herein, the maximum force applied to the force sensitive region may be higher than a finger press, making individual finger presses less identifiable. For example,  FIG. 31A  illustrates an example computing device  3100  that includes an integrated interface system with a trackpad region  3102  that extends along substantially an entire width of a top case  3101  of the device  3100 , as well as along sides of the keyboard  3104 . The whole top surface of the top case  3101  (or substantially all of the top surface) of the computing device  3100  may be force sensitive, thus facilitating detection of force inputs both on a keyboard  3104  (which may be a mechanical keyboard or a virtual keyboard) as well as the trackpad region  3102 . 
     As described herein, the integrated interface system may be configured to distinguish between different types of inputs, such as inputs applied to the keyboard  3104  and the trackpad region  3102  using touch and/or force sensing systems. For example, if the force and/or touch sensing system determines an input that satisfies a particular force threshold being applied to the trackpad region  3102 , a trackpad input (e.g., a “click”) may be registered. If the force and/or touch sensing system determines an input that satisfies a particular force threshold being applied to the keyboard region  3104 , a key input may be registered. Accordingly, the touch and force sensing systems may be used to distinguish between several different types of inputs that may be applied to the top case  3101  and to cause the device to react differently based on the location of the input. For example, a key input may cause a letter or character to be displayed on a display, and a trackpad input may correspond to a mouse click or otherwise cause a selection event in a user interface of a device. As used herein, inputs applied to functionally different regions of an integrated interface system (e.g., a keyboard region, a trackpad region, a virtual key region, etc.) may be referred to as different types of inputs, and inputs having different forces (e.g., taps versus presses) may be referred to as different types of inputs. This may largely mirror the expectation of a user that providing inputs to different regions (and/or providing different amounts of force) will cause the device to perform different types of functions. Further, as described herein, different types of haptic outputs may be associated with or produced in response to the detection of different types of inputs. 
     Because of the size and locations of the force sensitive input regions of the device  3100 , the force from a user&#39;s hands  3106 ,  3108  resting on the top case  3101  (and in particular on the trackpad region  3102 ) during typing may make it more difficult to differentiate or detect the relatively smaller forces applied by each finger during typing. More particularly, force sensors may not be able to determine with sufficient accuracy where a particular force is being applied, and thus cannot determine whether a force is due to typing or a tap input, or due to the weight of a user&#39;s palms. This may occur, for example, where a single force sensor or global force sensing system is used, instead of having different force sensors for different regions of the top case  3101 . Accordingly, techniques are used to ignore or reduce the effects of forces that do not correspond to actual inputs (e.g., palm forces) in order to better identify forces that do correspond to actual inputs (e.g., actuations of keys or taps on virtual keys). 
     For example, the influence of palm weight may be cancelled or ignored by using touch and/or force sensors to determine whether a user&#39;s palms are resting on the trackpad region  3102  at a given time, and then changing a threshold force that causes an input to be registered. The presence of a user&#39;s palms can be determined in a variety of ways. For example, a touch sensor associated with the trackpad region  3102  may identify a touch input that is indicative of a large object (such as a palm, as compared to a finger) being in contact with the trackpad region  3102 . As another example, a keyboard contact sensor may determine that a user&#39;s fingers are in contact with one or more keys of the keyboard  3104 , which can indicate that a user&#39;s palms are most likely resting on the trackpad region  3102 . Other techniques for determining whether a user&#39;s hands are resting on the top case  3101  may be used, including proximity sensors, force sensors, operational heuristics (e.g., whether typing input is being detected), or the like. Moreover, any combination of these (or other) techniques may be used together. 
     Once it is determined that a user&#39;s hands are resting on the top case  3101  or the trackpad region  3102 , the device  3100  may operate in a palm-reject mode in which a different algorithm or technique is used to detect typing or other touch inputs. For example, when operating in the palm-reject mode, a force threshold that causes a device to register a touch or typing input may be raised by a certain amount. For example, if a single tap for a typing input typically results in a 100 gram force (not including any contribution from a user&#39;s hands on the top case  3101 ), and the weight of a user&#39;s hands typically results in a 3000 gram force on the top case, the force threshold may be raised to 3100 grams. That is, only forces that are at or above 3100 grams will be registered as inputs. When the palm-reject mode is not active, the force threshold for determining or detecting a typing input may be different than when the palm-reject mode is active. Thus, continuing the example above, if the user&#39;s palms are not detected, the threshold force for registering an input from a touch event may be 100 grams. 
     In some cases, the forces associated with typing inputs and a user&#39;s palms resting on the top case  3101  are determined in real time, for individual users, by one or more force sensors or sensing systems. Accordingly, force thresholds for detecting typing inputs may also be based on the characteristics of a particular user. For example, a force sensor may determine that when a user is resting his or her hands on the top case, there is a 2000 gram force associated with just the user&#39;s hands, and when the user types, individual typing inputs correspond to an 80 gram force. Accordingly, the device may set a threshold at 2080 grams for that particular user. The forces associated with a user&#39;s hands and/or typing input may be determined dynamically and without the user&#39;s knowledge, or there may be a calibration routine in which a user rests his or her hands on the top case and/or provides typing inputs. The device may then determine appropriate force thresholds for typing inputs when the user&#39;s hands are or are not resting on the top case. 
     As another example, the force of a particular user&#39;s hands may be measured by determining that the user&#39;s hands are in a typing position but no input is being provided (e.g., by determining that the detected force is not changing), and then storing the detected force as a personalized baseline value. When the device  3100  is in the palm-reject mode, the force threshold may be increased by the baseline value. Thus, the force threshold can be changed by a customized amount to accommodate users that apply different weights with their hands during typing. 
     Another technique for differentiating typing or other touch inputs (e.g., clicks) from palm forces or other continuous, non-input related forces is to use accelerometers to differentiate between different types of forces. For example, a typing or click input may impart an impulse to the top case  3101  that may cause the top case  3101  and/or the device  3100  to move, even a very small amount, over a short time period. On the other hand, the weight of a user&#39;s palms during typing or other use of the device  3100  may not produce such impulses, or may produce impulses that are distinguishable from those produced by typing or clicking inputs. Accordingly, the device  3100  may include accelerometers that detect impulses. When the device  3100  detects an impulse, it may register or detect a force input in response to detecting the impulse. Where it is desired to know the location of the force input, the device  3100  may use location information from a touch sensor in conjunction with the accelerometer information to determine where the force input was applied. Accelerometers may be coupled to the top case  3101 , or any other suitable location within the device  3100 . 
     Yet another technique for determining when a force input is being applied to the device  3100  includes using microphones to detect when a force input is being applied. In particular, whereas a user&#39;s palms resting on the top case  3101  may be relatively silent, force inputs from a user&#39;s fingers striking keys (mechanical or virtual) or tapping on a trackpad or other touch or force sensitive region may produce more distinct and/or detectable sounds. Accordingly, the device  3100  may include one or more microphones that detect the sounds associated with typing events. Force inputs that are not coincident with sounds (e.g., from hands resting on the top case  3101 ) are ignored, while force inputs that are coincident with sounds (e.g., from typing or clicking) are registered as an input. 
       FIG. 31A  illustrates a scenario where a user is typing while the user&#39;s hands  3106 ,  3108  are resting on the trackpad region  3102 . In this case, palm-rejection techniques are used to ignore the force of the user&#39;s hands on the trackpad region  3102  while detecting force inputs applied to the keyboard  3104 .  FIG. 31B  illustrates another scenario, where one hand  3106  is resting on the trackpad region  3102  and the other hand  3108  is providing a force input to the trackpad region  3102 . Similar palm-rejection techniques may be used in this scenario to detect the input to the trackpad region  3102  while ignoring the force from the resting hand  3106 . Indeed, palm-rejection techniques may be used to ignore the force from resting hands while detecting inputs at other locations, such as on a virtual key region, regions of the top case that are on a side of the keyboard, or the like. 
     In order to effectively detect the varied types of touch and force inputs that may be applied to a computing device as described herein, it may be advantageous to know when a user is in a typing position, such as when the user&#39;s fingers are on the keyboard. This information may be used, for example, to determine whether or not the device should be operating in a palm-reject mode, or any other appropriate operating mode (e.g., a “typing” mode). 
       FIG. 32A  depicts an example computing device  3200  that includes a sensor system for determining when a user&#39;s hands are in a typing position. The computing device  3200  includes a top case  3202  and a bottom case  3204 , which are similar to other top and bottom cases described herein. The computing device  3200  also includes a keyboard  3206  (which may be a mechanical keyboard, a virtual keyboard, or a hybrid of these types) and a sensor system that detects the presence of a user&#39;s fingers on the keyboard  3206 . The sensor system may include a light curtain sensor that includes a light emitter  3208  and a detector  3210 . As shown, the light emitter  3208  is positioned along one side (e.g., a bottom side) of the keyboard  3206 , and the detector  3210  is positioned along an opposite side (e.g., a top side) of the keyboard  3206 , though other configurations and placements are also contemplated. 
       FIGS. 32B-32C  depict partial cross-sectional views of the device  3200 , viewed along section I-I in  FIG. 32A . The light emitter  3208  and the detector  3210  may be coupled to the top case  3202  on opposite sides of a recessed region  3211  in which the keyboard  3206  ( FIG. 32A ) is positioned. In particular, the light emitter  3208  may be positioned such that light  3214  is emitted through the top case  3202  (which may be glass, ceramic, or another light-transmissive material) above the keys of the keyboard. When a user places a finger on or near a key, the finger may interrupt the light  3214  so that the light  3214  is no longer detected by the detector  3210 , as shown in  FIG. 32C . When the detector  3210  no longer detects the light  3214 , the computing device  3200  may determine that a user&#39;s hands are in a typing position, with his or her fingers on (or very close to) the keycaps. When the computing device  3200  determines that the user&#39;s hands are in a typing position, it may enter a palm rejection mode, or launch an application or a text input box (e.g., a search input field), or perform any other desired action. 
     The light emitter  3208  and detector  3210  may be configured to emit and detect multiple light beams, so that even a single finger on a single key can be detected. For example, the light emitter  3208  may produce a series of parallel light beams that are separated by a distance that is less than the average (or the smallest) human finger. For example, the light beams may be separated by between about 1.0 and 10.0 mm. 
       FIG. 32D  depicts a partial cross-sectional view of the device  3200 , viewed along section I-I in  FIG. 32A , showing an example in which a light emitter  3216  emits light  3218  substantially vertically (or otherwise non-horizontally) through the top case  3202 . A detector  3220  (which may be part of a single sensor that includes both the emitter  3216  and the detector  3220 ) may determine whether an object has interrupted the light  3218  in an area above the keyboard (e.g., within about 6 inches above the keyboard, or any other suitable distance), and as such, can be used to determine whether a user&#39;s hands have been placed on the keyboard. As noted above, the top case  3202  may be glass, ceramic, or another light-transmissive material, thus allowing the emitter  3216  and the detector  3220  to emit and detect light through the top case  3202 .  FIG. 32D  shows the emitter  3216  and detector  3220  positioned next to a sidewall that defines the recessed region  3211 . In other examples, the emitter  3216  and detector  3220  may be positioned elsewhere, such as along a bottom surface of the recessed region  3211 , or any other suitable location. Where the emitter  3216  and detector  3220  are positioned on the bottom surface of the recessed region  3211 , the light  3218  may be projected through a gap between the sidewall of the recessed region  3211  and a side of the keycap  3212 . 
       FIG. 32E  depicts a partial cross-sectional view of the device  3200 , viewed along section I-I in  FIG. 32A , showing an example in which a proximity sensor  3222  is used to detect the presence or absence of a user&#39;s fingers near the keyboard. The proximity sensor  3222  may use any suitable sensing technology to detect the user&#39;s hands, including ultrasonic sensing, capacitive sensing, optical sensing, infrared sensing, thermal sensing, cameras or other imaging sensors, radar, light detection and ranging (LIDAR), or the like. While the proximity sensor  3222  is shown as sensing through the top case  3202 , in other examples the top case  3202  may have one or more openings to allow the proximity sensor  3222  to sense the presence or absence of a user&#39;s fingers. Further, while  FIG. 32E  shows the proximity sensor  3222  directed upwards, a proximity sensor may be directed in another direction. The proximity sensor  3222  may also be positioned elsewhere in a device, and may determine whether a user is interacting with a keyboard by detecting other areas of a user&#39;s hands, arms, fingers, and/or wrists. 
     As noted above, keyboards for computing devices described herein may include virtual or mechanical keys (or both). Mechanical keys provide several functionalities, as illustrated in  FIGS. 33A-33B , which are schematic illustrations of a mechanical input key  3300 . The key  3300  includes an interface member  3302  that a user contacts or presses in order to register an input. In some cases, the interface member  3302  is a keycap. The interface member  3302  is mechanically coupled to a computing device (represented by the base  3304 ) with a mechanism  3306 . The mechanism  3306  produces a tactile response when the interface member  3302  is depressed, as shown in  FIG. 33B , and also imparts a returning force on the interface member  3302  to return the interface member  3302  to an unactuated state. The tactile response may be represented or defined by a particular force response curve. For example, the force response curve for a key  3300  may be substantially flat, such that the force imparted by the mechanism  3306  in opposition to an actuation force (indicated by arrow  3308 ) does not change throughout the travel of the interface member  3302 . Alternatively, the force response of the key  3300  may cause the opposing force to increase as the interface member  3302  is pressed, until a release point is reached at which point the opposing force may decrease (e.g., similar to a “buckling” response). This type of force response curve may produce an audible and/or physical click that is characteristic of some mechanical keys. Any suitable mechanism or combination of mechanisms may be used for the mechanism  3306 , including scissor mechanisms, hinge mechanisms, rubber domes, coil springs, collapsible metal domes, elastomer members, magnets, and so on. 
     The key  3300  also includes a key make sensor  3310  that is used to determine when the key  3300  is pressed sufficiently for a device to register an input. In  FIGS. 33A-33B , the key make sensor  3310  is shown in schematic form. The key make sensor  3310  may include any suitable combination of electrical, mechanical, and/or electromechanical components, some examples of which are described herein. 
       FIG. 33A  depicts the key  3300  in an unactuated state with the key make sensor  3310  shown in an open state.  FIG. 33B  depicts the key  3300  in an actuated state (e.g., pressed downward) with the key make sensor  3310  in a closed state. The key make sensor  3310  may be closed when the interface member  3302  reaches the end of its travel (e.g., when it bottoms out), or at another point along its travel (e.g., coincident with or immediately after an audible or physical click is produced). 
     Computing devices described herein may have top cases formed from glass (or other material) that have no openings or holes in the top surface to allow keys to mechanically access the interior of the computing device. For these computing devices, the mechanism  3306  and the key make sensor  3310  are selected to provide functionality described above without mechanically coupling to the inside of the computing device through an opening in the top case. 
       FIGS. 34A-34B  depict partial cross-sectional views of an example computing device  3400 , showing an example system for detecting key makes through a top case. The cross-sectional views may correspond to a view of a computing device viewed along section J-J in  FIG. 13A . The computing device  3400  includes a keycap  3402  (an interface member), a top case  3406 , and a support mechanism  3404  movably coupling the keycap  3402  to the top case  3406 . The computing device  3400  further includes a sensor  3410 , or a portion of a sensor such as an electrode layer, positioned below the top case  3406 . 
     The top case  3406  may correspond to top cases described above, and may be formed from glass, ceramic, plastic, or any other suitable material. As shown, the top case  3406  does not include an opening through which the keycap  3402 , or any other component above the top case  3406 , can pass through. 
     The support mechanism  3404  may be any suitable mechanism, such as a scissor mechanism, a butterfly hinge, or the like. The support mechanism  3404  may be configured to produce tactile or audible clicks or other feedback when the keycap  3402  is depressed. The support mechanism  3404  may also include a resilient member that opposes forces applied to the keycap  3402 , thereby producing a suitable force response by producing a force that opposes an actuation force and/or returns the keycap  3402  to an unactuated position when the actuation force is removed. The resilient member may be a coil spring, an elastomer member, a rubber dome, or the like. 
     The sensor  3410  may detect the presence or proximity of objects above the top case  3406 , and may use any suitable mechanism or rely on any suitable phenomena to do so. For example, the sensor  3410  may be or may be part of a capacitive sensing system that can detect changes in electrical fields above the top case  3406  caused by nearby objects such as fingers, styli, etc. The sensor  3410  may use self-capacitance, mutual capacitance, or any other technique for capacitively coupling to a finger or object. 
     To allow the sensor  3410  to capacitively couple to a user&#39;s finger  3408  (or otherwise use capacitive sensing principles to detect the user&#39;s finger  3408 ), the top case  3406 , the keycap  3402 , and the support mechanism  3404  may be substantially nonconductive (e.g., they may be formed from dielectric materials). More particularly, by using substantially nonconductive materials, such as glass, plastic, ceramic, sapphire, or the like, the top case  3406 , keycap  3402 , and support mechanism  3404  may not interfere with a capacitive coupling between the finger  3408  and the sensor  3410 , thus allowing the sensor  3410  to capacitively couple directly to the finger  3408  through the intervening components. 
     As shown in  FIG. 34A , when the finger  3408  is on the keycap  3402  and the keycap  3402  is unactuated (e.g., not depressed), the sensor  3410  capacitively couples to the finger  3408 . Nevertheless, the sensor  3410  (or circuitry of the sensor  3410 ) may determine that the capacitive influence of the finger  3408  is not indicative of an actuated key. When the keycap  3402  is sufficiently depressed, as shown in  FIG. 34B , the sensor  3410  may determine that the capacitive influence of the finger  3408  has satisfied a threshold value, and the sensor or sensor circuitry may register an actuation of the key. 
     The sensor  3410  and the support mechanism  3404  may be configured so that a key make, or actuation of the key, is sensed at a particular point along the travel of the keycap  3402 . For example, the sensor  3410  may be configured to register an actuation of the key when the keycap  3402  reaches an end of its travel (e.g., when the finger  3408  is at its closest possible point to the sensor  3410 ). In some cases, the point at which a key actuation is registered may be variable, and need not be at the end of the key travel. For example, the keycap travel at which the key actuation is registered may be established at a lower value (e.g., less keycap travel) for users who type with lower force than for users who type with higher force. The particular travel target for registering a key actuation may be determined dynamically by determining an average key travel of a user during typing and setting the travel target to the average travel (or some other value based on the user&#39;s typing style). 
     As another example, where the support mechanism  3404  produces a click or other audible or tactile feedback at an intermediate travel of the keycap  3402 , the sensor  3410  may register actuation of the key when the finger  3408  is at or immediately past the point where the click is produced. In some cases, the sensor  3410  (and/or associated circuitry of the sensor  3410 ) can also detect the presence of a user&#39;s finger on or above the keycap  3402  without the keycap  3402  being moved. Such sensing may be used to determine whether or not a user&#39;s hands are in a typing position, to detect gesture inputs applied to or above the keycap  3402 , and/or to determine an intended key target based on the actual location of the user&#39;s contact with the keycap  3402  (e.g., when two adjacent keys are pressed at substantially the same time, a key that is pressed only at its edge may have been struck by mistake; by detecting the location of the contact such key actuations can be ignored). 
     The sensor  3410  may also be able to determine the particular location of a particular input. In this way, the sensor  3410  can determine what key is being selected. More particularly, when the sensor  3410  detects an actuation event, it may compare the location of the actuation event with a key map that correlates each key of a keyboard to a particular location or position on the top case  3406 , and determine what key was actuated. 
       FIGS. 35A-35B  depict partial cross-sectional views of an example computing device  3500 , showing another example system for detecting key makes through a top case. The cross-sectional views may correspond to a view of a computing device along section J-J in  FIG. 13A . The computing device  3500  is similar to the computing device  3400  described with respect to  FIGS. 34A-34B , but instead of the sensor capacitively coupling to a user&#39;s finger or other object that is placed on a keycap, the sensor capacitively couples to a conductive or other capacitively detectable portion of the keycap. 
     More particularly, the computing device  3500  includes a keycap  3502  (an interface member), a top case  3506 , and a support mechanism  3504  movably coupling the keycap  3502  to the top case  3506 . The computing device  3500  further includes a sensor  3510 , or a portion of a sensor such as an electrode layer, positioned below the top case  3506 . These components are the same as or similar to the analogous components described above with respect to  FIGS. 34A-34B . 
     The computing device  3500  also includes an electrode  3512  coupled to a movable part of a key, such as the keycap  3502 . The sensor  3510  capacitively couples to or otherwise detects the proximity of the electrode  3512 , and can determine a distance, or a value indicative of the distance, between the electrode  3512  and the sensor  3510 . Thus, the sensor  3510  can determine when the key is unactuated, as shown in  FIG. 35A , and when the key is actuated, as shown in  FIG. 35B . 
     The electrode  3512  may be formed from or include any suitable material or materials, including ITO, indium gallium oxide, gallium zinc oxide, indium gallium zinc oxide, metal nanowire, nanotube, carbon nanotube, graphene, conductive polymers, a semiconductor material, a metal oxide material, copper, gold, constantan, or the like. The electrode  3512  may use light-transmissive materials or opaque materials, depending on the application (such as whether a display is positioned below the electrode). Also, the electrode  3512  may be any suitable size or have any suitable dimensions. In some cases, the electrode  3512  is smaller than the keycap  3502 , as shown in  FIGS. 35A-35B . In other cases, the electrode  3512  covers substantially the entire bottom or top surface of the keycap  3502 . Furthermore, the electrode  3512  is shown attached to the keycap  3502 , but it may be positioned in any movable part of a key mechanism, including the top surface of the keycap  3502 , an arm of the support mechanism  3504 , or the like. The electrode  3512  may be a glyph on the keycap  3502 , where the glyph is formed from or includes a conductive material, such as a conductive paint or a conductive dopant applied to a material that forms the glyph. 
       FIGS. 36A-36B  depict partial cross-sectional views of an example computing device  3600 , showing another example system for detecting key makes through a top case. The cross-sectional view may correspond to a view of a computing device along section J-J in  FIG. 13A . The computing device  3600  is similar to the computing devices  3400  and  3500  described with respect to  FIGS. 34A-35B , but instead of a capacitive sensor, an optical sensor is used to detect a key make. 
     The computing device  3600  includes a keycap  3602  (an interface member), a top case  3606 , and a support mechanism  3604  movably coupling the keycap  3602  to the top case  3606 . These components are the same as or similar to the analogous components described above with respect to  FIGS. 34A-35B . 
     The computing device  3600  further includes an optical emitter  3614  and an optical detector  3616  positioned below the top case  3606  (and positioned on a circuit board or other substrate  3610 ). The optical emitter  3614  is configured to emit light through the top case  3606  and towards the keycap  3602 , while the optical detector  3616  is configured to detect light passing through the top case  3606 . Because light must pass through the top case  3606  in order for the depicted optical sensing system to operate, the top case  3606  must be at least partially light-transmissive or transparent. Accordingly, the top case  3606  may be formed from glass, plastic, ceramic, or any other suitable light-transmissive material. While some portions of the top case  3606  may not be light-transmissive (e.g., they may be painted or coated), at least the portions above the emitter  3614  and the detector  3616  are light-transmissive (e.g., at least partially transparent). 
     The optical sensor operates by causing the emitter  3614  to emit light towards the keycap  3602 , and monitoring the detector  3616  to determine whether a threshold amount or intensity of light has been detected. The amount or intensity of light detected by the detector  3616  may depend on how far the keycap  3602  is from the emitter  3614  and detector  3616 . For example, when the keycap  3602  is in an unactuated state, as shown in  FIG. 36A , light emitted by the emitter  3614  may be reflected from a surface  3612  of the keycap  3602  such that a threshold amount or intensity of light does not reach the detector  3616 .  FIG. 36A  depicts a light path  3618  where the light does not reach the detector  3616  at all. Where the emitter  3614  emits a focused or directed light beam, the path  3618  may be representative of an actual light path. However, the light emitted from the emitter  3614  may not be a single focused or directed beam, but rather may have a more diffuse or unfocused shape. In such cases, the light path  3618  represents a state in which the detector  3616  does not detect a threshold value of light, and does not necessarily correspond to a particular beam path. 
     When the keycap  3602  is moved downwards (e.g., when it is pressed downwards by a finger or other object), the surface  3612  reflects more light into the detector  3616 , as illustrated by the light path  3620  in  FIG. 36B . Once a threshold amount or intensity of light is detected, the detector  3616  may register a key press. 
     The surface  3612  may be part of (e.g., integral with) the keycap  3602 . For example, the surface  3612  may be a bottom surface of the keycap  3602 . Alternatively, the surface  3612  may be attached or coupled to the keycap  3602 , such as with an adhesive film, a tape, a paint or coating, an additional member, or the like. The surface  3612  may be selected to have a particular optical property, such as a particular reflectance, a particular focusing or defocusing (e.g., diffusing) effect, or the like. For example, the surface  3612  may be a reflective coating or film that is applied to the bottom surface of the keycap  3602 . 
     Other types of optical or other sensors may be used instead of or in addition to the emitter/detector arrangement described with respect to  FIGS. 36A-36B . Such sensors may include ultrasonic sensors, infrared sensors, thermal sensors, cameras or other imaging sensors, radar sensors, or the like. 
       FIGS. 37A-37B  depict partial cross-sectional views of an example computing device  3700 , showing another example system for detecting key makes through a top case. The cross-sectional views may correspond to a view of a computing device along section J-J in  FIG. 13A . The computing device  3700  is similar to the computing devices  3400 ,  3500 , and  3600  described with respect to  FIGS. 34A-36B , but the key make sensor is disposed on or coupled to the key mechanism rather than within a base portion of the computing device  3700  (e.g., under the top case of the computing device  3700 ).  FIG. 37A  shows the key mechanism in an undepressed or unactuated state, and  FIG. 37B  shows the key mechanism in a depressed or actuated state. 
     The computing device  3700  includes a keycap  3702  (an interface member), a top case  3706 , and a support mechanism  3704  movably coupling the keycap  3702  to the top case  3706 . These components are the same as or similar to the analogous components described above with respect to  FIGS. 34A-36B . 
     The computing device  3700  includes a key make sensor  3712  coupled to or integrated with the keycap  3702  (or any other suitable portion of the key mechanism). The key make sensor  3712  may be any suitable sensor or mechanism that can detect when the keycap  3702  has been actuated, and produce a signal that can be transmitted (or can cause transmission of a signal) to a receiver within the computing device  3700 . For example, the key make sensor  3712  may be an optical sensor, such as the optical sensor described above with respect to  FIGS. 36A-36B . In such cases, the key make sensor  3712  may include both an optical emitter and an optical detector, and the computing device  3700  may include a reflective material or surface to reflect light from the optical emitter into the optical detector when the keycap  3702  is depressed. Alternatively, the key make sensor  3712  may be a switch, dome, capacitive sensor, inductive sensor, acoustic sensor (e.g., a microphone, ultrasonic transducer), piezoelectric sensor, accelerometer, or any other suitable sensor. 
     The computing device  3700  includes a transmitter  3718  coupled to or integrated with the keycap  3702  (or any other suitable portion of the key mechanism). The transmitter  3718  communicates with or otherwise receives information or signals from the key make sensor  3712 , and sends signals, data, or other information to a receiver  3720  that is within the computing device  3700  (on a circuit board or other substrate  3710 ). The signals, data, or other information (indicated by arrow  3722 ) may indicate when and/or whether a key make has been detected by the key make sensor  3712 . The computing device  3700  may take various actions in response to detecting a key make via the receiver  3720 , such as displaying a letter or other character in a graphical user interface, manipulating a graphical user interface, or performing any other operation or action. 
     The receiver  3720  may be positioned below the top case  3706 . Because the top case  3706  may be continuous (e.g., having no openings beneath the keycap  3702 ), there may be no physical or wired connection between the receiver  3720  and the transmitter  3718 . Accordingly, the transmitter  3718  and receiver  3720  may communicate wirelessly through the material of the top case  3706 . Example wireless communication techniques that may permit trans-top-case communications include electromagnetic communications (e.g., radio, optical, inductive, or any other suitable electromagnetic communication type.), ultrasonic communication, and the like. For example, the transmitter  3718  may be a radio transmitter and the receiver  3720  may be a radio receiver. As another example, the transmitter  3718  may be an optical emitter and the receiver  3720  may be an optical detector. Also, the transmitter  3718  and the receiver  3720  may be transmitter/receivers, providing bi-directional communications between the keycap  3702  and components within the base portion of the computing device  3700  (e.g., a processor). 
     The computing device  3700  may also include a power receiver  3714  that electromagnetically couples to a power transmitter  3716  that is positioned below the top case  3706  (on a circuit board or other substrate  3710 ). The power transmitter  3716  transfers power to the power receiver  3714 , which in turn powers the key make sensor  3712  and the transmitter  3718 . (The power receiver  3714  may also charge an energy storage device, such as a battery or capacitor, that powers the key make sensor  3712  and the transmitter  3718 .) More particularly, the power transmitter  3716  transfers power wirelessly, through the top case  3706 , to the power receiver  3714 . 
     Power may be transferred between these components by using any suitable wireless power transfer techniques, including inductive coupling, capacitive coupling, or the like. In the case of inductive and capacitive coupling, the power transmitter  3716  and the power receiver  3714  may include complementary coils or other electrical components that inductively and/or capacitively couple to another through the top case  3706 . In such cases, the top case  3706  may be formed from or include a dielectric (e.g., glass, plastic, ceramic, sapphire, plastic, etc.), thereby facilitating the inductive and/or capacitive coupling between the power transmitter  3716  and power receiver  3714  (as well as the wireless communications between transmitter and receiver  3718 ,  3720  discussed above). 
     The components shown on the keycap  3702 , including the power receiver  3714 , the transmitter  3718  (e.g., for transmitting indications of a key make), and the key make sensor  3712 , may be coupled to or integrated with the keycap  3702  in any suitable manner. For example, they may be attached to the keycap  3702  using adhesives, fasteners, or the like. As another example, they may be at least partially encapsulated in the material of the keycap  3702 . This may be accomplished with insert molding techniques. Alternatively, they may be coupled to or integrated with any other suitable component or part of the key mechanism instead of the keycap  3702 . For example, the power receiver  3714  may be coupled to a top surface of the top case  3706  and may be electrically coupled to the transmitter  3718  and/or the key make sensor  3712  via a flexible circuit board, wire, or the like. 
       FIGS. 37A-37B  show an example where each individual key mechanism of a keyboard may independently communicate key makes to components within the computing device  3700  (e.g., receivers, such as the receiver  3720 ). In some cases, multiple keys or key mechanisms (such as the entire keyboard) may be communicatively coupled together, and a single communication link may be used to communicate key make information for multiple keys. For example, a key assembly may include multiple keys coupled to a base layer or structure. The key assembly may include all of the mechanical keys of a particular computing device, such as an entire notebook computer keyboard, or a subset of keys (e.g., a row of keys or any other grouping of keys). The keys of the key assembly may include key make sensors including optical sensors, dome switches, capacitive or inductive sensors, or any other suitable sensor or combinations of sensors. A single transmitter coupled to the key assembly may receive or detect key make indications from the key make sensors, and transmit data or other information indicative of the key makes to components within the computing device  3700 . The receiver and transmitter of such a keyboard may use any suitable wireless communication technique that can communicate through the material of the top case  3706 , such as optical communications, radio communications, or the like. Key assemblies such as the foregoing may reduce the number of wireless receivers and transmitters that are used to communicate key makes, and may simplify assembly and manufacturing processes. For example, instead of coupling multiple individual key mechanisms to a device, the keys can be pre-assembled on a base structure that can more easily or quickly be coupled to a top case of the device. 
     Computing devices may be configured to illuminate portions of a keyboard. For example, in order to improve the readability of the keys or otherwise produce a particular visual appearance, keycap glyphs and the spaces or gaps between keycaps (e.g., a keyboard web) may be illuminated. In cases where a computing device includes a continuous top case, it may not be possible to mount electrical light emitting components on the top surface of the top case and power them via mechanical connections to the interior of the computing device. Accordingly, computing devices with continuous top cases as described herein may include lighting systems that transfer light, or power for light emitters, through the top case and without mechanical couplings. 
       FIG. 38  depicts a partial cross-sectional view of an example computing device  3800 , showing an example lighting system for a keyboard. The cross-sectional view shown in  FIG. 38  may correspond to a view of a computing device along section J-J in  FIG. 13A . 
     The computing device  3800  may include a keycap  3802 , a top case  3806 , and a support mechanism  3803  movably coupling the keycap  3802  to the top case  3806 . The computing device  3800  further includes a sensor  3808  (e.g., a portion of a sensor such as an electrode layer), positioned below the top case  3806 . These components are the same or similar to the analogous components described above with respect to  FIGS. 34A-35B . The computing device  3800  further includes a lighting layer  3810  below the sensor  3808  (or anywhere below the top case  3806 ) that includes a light source  3804 . The lighting layer  3810  may include multiple light sources  3804 , such as at least one light source  3804  for each key of a keyboard. 
     The light source  3804  may be a light emitting element, such as an LED, OLED, incandescent or fluorescent element, or the like. Alternatively, the light source  3804  may be an end of a light guide or light pipe that guides light from a light emitting element located at a different location within the computing device  3800 . In some cases, the light source  3804  is an LED (or other light source) mounted to a substrate such as a circuit board (e.g., a flex circuit). 
     As noted above, the top case  3806  and the sensor  3808  may be light-transmissive (e.g. transparent or translucent), thus allowing light from the light source  3804  to pass therethrough and towards the keycap  3802 . A first portion of the light, represented by light paths  3814  and  3816 , may pass through the keycap  3802 , such as through a transparent or translucent glyph portion of the keycap  3802 , to illuminate the glyph. A second portion of the light, represented by light paths  3812 , may be configured to reflect off of the bottom surface of the keycap  3802  and illuminate the top case  3806  and/or otherwise illuminate the gaps between adjacent keycaps of the keyboard (e.g., the keyboard web). The light paths  3812  may produce a halo or frame of light around the keycap  3802 . The bottom surface of the keycap  3802  and/or portions of the top case  3806  may include reflective materials, coatings, or the like to improve the efficiency of light transfer and/or to direct light in desired directions. 
       FIG. 38  depicts light paths that illuminate both a keycap glyph and the gaps between keycaps (or the top case more generally). However, a computing device may use either of these light paths exclusively. For example, the keycaps may be opaque such that light only illuminates the keyboard web (e.g., producing halos or frames of light around each keycap). As another example, the light sources may direct light in a focused beam or path towards a keycap glyph, and may not illuminate the keyboard web (or may only illuminate the keyboard web or other keyboard components only an insignificant amount). 
       FIG. 39A  depicts a cross-sectional view of an example keycap  3900 , showing an example masking configuration that may define a glyph that can be illuminated by a light source. The keycap  3900  may correspond to the keycap  3802  shown in  FIG. 38 . 
     The keycap  3900  includes a light-transmissive (e.g., transparent or translucent) body portion  3902  and a mask  3904 . The body portion  3902  may act as a light guide or light pipe to transmit or otherwise allow light to pass therethrough. Accordingly, the body portion  3902  may be formed from or include a light-transmissive material, such as glass, plastic, polycarbonate, ceramic (e.g., a transparent or translucent ceramic), or the like. 
     The mask  3904  may be formed from or include any suitable opaque or substantially opaque material, such as a paint, ink, dye, film, or other material. As noted above, the body portion  3902  may act as a light guide or light pipe. In order to improve light transmission (and/or prevent light absorption by the mask  3904 ), the surface of the mask  3904  that faces the body portion  3902  may be reflective or otherwise configured to reduce light absorption. For example, the mask  3904  may include a film, coating, paint, dye, or any other suitable material or treatment on the inner surface of the mask  3904 . 
     A top opening  3906  in the mask  3904  may be in the shape of a glyph, such as a letter, number, character, function, icon, or any other symbol or shape. The glyph may indicate or suggest what operation the key performs when actuated. The mask  3904  may also form a bottom opening  3908  that allows light to enter the keycap  3900  and pass through the top opening  3906 , thereby illuminating the glyph, as illustrated by the light path  3910 . 
     In some cases, a bottom portion  3914  of the mask  3904  is configured to reflect light towards the top case or otherwise away from the keycap  3900 , for example to illuminate the gaps between adjacent keycaps, as illustrated by the light path  3912 . In such cases, the bottom portion  3914  of the mask  3904  may be formed from or include a reflective material. Alternatively, the bottom portion  3914  of the mask  3904  may be configured to absorb light to prevent or limit light from reflecting off of the bottom portion  3914 . In some cases, there is no mask on the bottom surface of the keycap  3900 . 
       FIG. 39B  depicts a cross-sectional view of another example keycap  3916 , showing an example masking configuration that may define a glyph that can be illuminated by a light source, as well as an unmasked side region that may allow light to escape from the sides of the keycap  3916 , thus illuminating the area surrounding the keycap  3916  (e.g., the keyboard web). 
     The keycap  3916  includes a light-transmissive body portion  3918  and a mask  3920 . The body portion  3918  may act as a light guide or light pipe to transmit or otherwise allow light to pass therethrough. Accordingly, the body portion  3918  may be formed from or include a light-transmissive material, such as glass, plastic, polycarbonate, ceramic (e.g., a transparent or translucent ceramic), or the like. 
     The mask  3920  may be formed from or include any suitable opaque or substantially opaque material, such as a paint, ink, dye, film, or other material. As noted above, the body portion  3918  may act as a light guide or light pipe. In order to improve light transmission (and/or prevent light absorption by the mask  3920 ), the surface of the mask  3920  that faces the body portion  3918  may be reflective or otherwise configured to reduce light absorption. For example, the mask  3920  may include a film, coating, paint, dye, or any other suitable material or treatment on the inner surface of the mask  3920 . Further, the mask  3920  may be configured to direct light out of openings in the mask  3920 , such as glyph openings and side openings, as described herein. 
     A top opening  3926  in the mask  3920  may be in the shape of a glyph, such as a letter, number, character, function, icon, or any other symbol or shape. The glyph may indicate or suggest what operation the key performs when actuated. The mask  3920  may also form a bottom opening  3922  that allows light to enter the keycap  3916  and pass through the top opening  3926 , thereby illuminating the glyph, as illustrated by the light path  3930 . 
     In some cases, the mask  3920  may define side openings  3924  along one or more sides of the body portion  3918 . The side openings  3924  allow light that enters the body portion  3918  through the bottom opening  3922  to pass through the body portion  3918  and exit the body portion  3918  around the sides, as illustrated by the light path  3928 . The light exiting the side of the body portion  3918  may illuminate the spaces between the keys (e.g., the keyboard web), and may produce a halo or frame of light around each key. The side openings  3924  may extend around an entire outer periphery of the body portion  3918  (e.g., such that the entire periphery or substantially the entire periphery allows light to pass therethrough), or only a portion of the periphery. For example, in cases where the body portion  3918  has a substantially square or rounded square shape with four sides, the mask may have side openings  3924  on one, two, three, or all four sides. 
     Whereas in the keycap  3900  ( FIG. 39A ) light is reflected off of the bottom portion of the mask, in  FIG. 39B  light is not shown reflecting off of the bottom portion of the mask  3920 . In particular, the light guide effect of the body portion  3918  and the side openings  3924  may illuminate the areas surrounding and/or between keycaps without reflecting light underneath the keycap. In such cases, a light source may direct light substantially only into the bottom opening  3922 . 
     The keycaps  3900  and  3916  may be used in any key mechanism or keyboard described herein. For example, the computing device shown in  FIG. 38  may include the keycap  3900  or the keycap  3916 . Also, a keyboard may include both types of keycaps in a single keyboard, or may include only one type of keycap for all of the keys of the keyboard. 
       FIG. 40A  depicts a partial cross-sectional view of an example computing device  4000 , showing another example system for illuminating a keycap and/or parts of a top case. The cross-sectional view may correspond to a view of a computing device along section J-J in  FIG. 13A . 
     The computing device  4000  includes a keycap  4002  (an interface member), a top case  4006 , and a support mechanism  4004  movably coupling the keycap  4002  to the top case  4006 . These components are the same or similar to the analogous components described above with respect to  FIGS. 34A-35B . 
     The top case  4006  may be transparent (such as a transparent glass, ceramic, plastic, etc.), translucent, or may otherwise be configured to act as a light guide to guide light from a light source, through the top case (e.g., along a planar direction), to light extraction features such as lens features  4008 ,  4010 . The lens features  4008 ,  4010  may be configured to direct from within the top case  4006  outwards. For example, the first lens feature  4008  may direct light towards a gap between two adjacent keycaps (or between a keycap and another adjacent component), and the second lens feature  4010  may direct light towards the underside of the keycap  4002 . Other types of light extraction features such as surface texturing, etching, doped regions, coatings, or the like may be used instead of or in addition the lens features shown in the figures. 
     The lens features  4008 ,  4010  may have any suitable shape or configuration to direct light along a desired path or direction. For example, the lens features  4008 ,  4010  may have a saw tooth profile, or may include one or more bumps, grooves, spikes, peaks, channels, or any other suitable shape or configuration. 
       FIG. 40B  is a top view of the top case  4006  shown in  FIG. 40A , showing an example arrangement of the first lens feature  4008  and the second lens feature  4010 . The first lens feature  4008  may substantially surround the keycap  4002  (shown in phantom lines) to illuminate the area surrounding the keycap (e.g., the keyboard web). The first lens feature  4008  may form a grid pattern, with each cell surrounding a different keycap (such as an additional keycap  4016  partially shown in  FIG. 40B ). The grid-patterned first lens feature  4008  may thus illuminate the gaps between multiple (or all) of the keys of a keyboard. The second lens feature  4010  may be positioned under the keycap  4002  to illuminate the keycap glyph, as described above. 
       FIG. 41A  depicts a cross-sectional view of an example computing device  4100 , showing another example system for illuminating a keycap and/or parts of a top case. The cross-sectional view may correspond to a view of a computing device along section J-J in  FIG. 13A . 
     The computing device  4100  includes a keycap  4102  (an interface member), a top case  4106 , and a support mechanism  4104  movably coupling the keycap  4102  to the top case  4106 . The keycap  4102  may be the same as or similar to the keycap  3900  described above with respect to  FIG. 39A , and the top case and support mechanism may be the same as or similar to the analogous components described above with respect to  FIGS. 34A-35B . 
     The computing device  4100  also includes a light source  4108  positioned above the top case  4106 . The light source may be an LED, OLED, incandescent or fluorescent element, or the like. The light source may be associated with a power receiver  4110  that electromagnetically couples to a power transmitter  4112  that is positioned below the top case  4106 . The power transmitter  4112  transfers power to the power receiver  4110 , which in turn powers the light source  4108 . (The power receiver  4110  may also charge an energy storage device, such as a battery or capacitor, that powers the light source  4108 .) More particularly, the power transmitter  4112  transfers power wirelessly, through the top case  4106 , to the power receiver  4110 . 
     Power may be transferred between these components by using any suitable wireless power transfer techniques, including inductive coupling, capacitive coupling, or the like. In the case of inductive and capacitive coupling, the power transmitter  4112  and the power receiver  4110  may include complementary coils or other electrical components that inductively and/or capacitively couple to another through the top case  4106 . In such cases, the top case  4106  may be formed from or include a dielectric (e.g., glass, plastic, ceramic, sapphire, plastic, etc.), thereby facilitating the inductive and/or capacitive coupling between the power transmitter  4112  and the power receiver  4110 . 
     In any of the illumination systems described above, components between the top case and the keycap, such as a support mechanism, dome housings, compliant members (e.g., rubber domes), or the like, may be transparent or translucent to allow light to pass therethrough to reach the keycap. Any such components may also act as light guides and may include lens features to direct light through or out of the components and in desired directions. 
       FIG. 41B  depicts a cross-sectional view of another example computing device  4120 , showing another example system for illuminating a keycap and/or parts of a top case. The computing device  4120  is similar to the computing device  4100  in  FIG. 41A  in that it uses a wireless power transfer system to provide power, through the material of a top case, to a light source. However, as described below, the light source is coupled to the keycap rather than to the top case. The cross-sectional view may correspond to a view of a computing device along section J-J in  FIG. 13A . 
     The computing device  4120  includes a keycap  4122  (an interface member), a top case  4125 , and a support mechanism  4124  movably coupling the keycap  4122  to the top case  4125 . The keycap  4122  may be the same as or similar to the keycap  3916  described above with respect to  FIG. 39B , and the top case and support mechanism may be the same as or similar to the analogous components described above with respect to  FIGS. 34A-35B . 
     The computing device  4120  also includes a light source  4132  above the top case  4125 . The light source may be coupled to or otherwise integrated with the keycap  4122 . The light source may be an LED, OLED, incandescent or fluorescent element, or the like. The light source  4132  may be associated with a power receiver  4130  that electromagnetically couples to a power transmitter  4134  that is positioned below the top case  4125 . The power transmitter  4134  transfers power to the power receiver  4130 , which in turn powers the light source  4132 , as described above. The power receiver  4130  may also charge an energy storage device, such as a battery or capacitor, that powers the light source  4132 . More particularly, the power transmitter  4134  transfers power wirelessly through the top case  4125  to the power receiver  4130 . Power may be transferred between these components by using any suitable wireless power transfer techniques as described above with respect to the power transmitter  4112  and the power receiver  4110 . Further, the top case  4125  may be formed from or include a dielectric (e.g., glass, plastic, ceramic, sapphire, plastic, etc.), thereby facilitating the wireless coupling between the power transmitter  4112  and the power receiver  4110 . 
     The light source  4132  may direct light into a body portion  4123  of the keycap  4122 . The body portion  4123  may be formed from or include a light-transmissive material that acts as a light guide or light pipe, as described above with respect to  FIG. 39B . The material may be glass, plastic, polycarbonate, ceramic (e.g., a light-transmissive ceramic), or the like. The keycap  4122  may also include an opaque or light shielding mask  4126  that defines a top opening  4128  (e.g., in the shape of a glyph or other symbol indicative of a character or key function) and one or more side openings  4140 . The body portion  4123 , the mask  4126 , and the top and side openings  4128 ,  4140  may function similar to the analogous components of the keycap  3916  in  FIG. 39B . For example, the body portion  4123  and the mask  4126  may direct light from the light source  4132  out of the top opening  4128  (illustrated by the light path  4136 ) and out of the side openings  4140  (illustrated by the light path  4138 ). 
     The power receiver  4130  and the light source  4132  may be incorporated in the keycap  4122  in any suitable way. For example, they may be attached to the body portion  4123  using adhesive, fasteners, interlocking structures (e.g., clips, latches, posts, heat stake joints), rivets, or the like. The power receiver  4130  and the light source  4132  may also be at least partially encapsulated in the body portion  4123 , such as by insert molding. More particularly, the power receiver  4130  and the light source  4132  may be placed into a mold, and the material for the body portion  4123  may subsequently be introduced into the mold. The material may form at least partially around the power receiver  4130  and the light source  4132 , thereby at least partially encapsulating the power receiver  4130  and the light source  4132  and retaining these components to the body portion  4123 . 
     In any of the illumination systems described above, components between the top case and the keycap, such as a support mechanism, dome housings, compliant members (e.g., rubber domes), or the like, may be light-transmissive to allow light to pass therethrough to reach the keycap. Any such components may also act as light guides and may include lens features to direct light through or out of the components and in desired directions. 
     While  FIG. 41B  shows an example in which a keycap-mounted light source  4132  is powered wirelessly (e.g., using trans-top-case power transfer), keycap-mounted light sources may also be powered using physical conductors.  FIG. 41C  depicts a cross-sectional view of another example computing device showing another example system for illuminating a keycap and/or parts of a top case. In particular, a keycap  4148  (which may be similar to the keycap  4122  in  FIG. 41B ) may include a light source  4150  (which may be similar to the light source  4132  in  FIG. 41B ). The light source  4150  may be electrically connected to a circuit board  4146  through an opening in a top case  4144  via a flexible conductor  4142 . The flexible conductor  4142  may be any suitable material, such as a flexible circuit board material with a conductive trace. The flexible conductor  4142  may be configured to tolerate repeated flexing due to actuation of the keycap  4148  during normal typing use. In some cases, the flexible conductor  4142  may be configured to sustain up to 20 million keypresses (or more) without failing or breaking. 
       FIGS. 42A-42B  depict partial cross-sectional views of another example computing device with an illuminated keyboard, viewed along section J-J in  FIG. 13A . In particular,  FIGS. 42A-42B  depict a computing device in which a portion of a top case acts as a light guide or light pipe to direct light into a body of a keycap of a key mechanism.  FIG. 42A  shows the key mechanism in an undepressed or unactuated state, and  FIG. 42B  shows the key mechanism in a depressed or actuated state. 
     The computing device  4200  includes a keycap  4202  (an interface member), a top case  4206 , and a support mechanism  4204  movably coupling the keycap  4202  to the top case  4206 . The top case  4206  and support mechanism  4204  may be the same as or similar to the analogous components described above with respect to  FIGS. 34A-35B . 
     The computing device  4200  also includes a light source  4212  positioned below the top case  4206 . The light source  4212  may be an LED, OLED, incandescent or fluorescent element, or the like. In some cases, the light source  4212  is an LED (or other light source) mounted to a substrate such as a circuit board  4210  (e.g., a flex circuit). 
     The light source  4212  directs light into a light guide feature  4214  formed into or coupled to the top case  4206 . The light guide feature  4214  may be a protrusion having a square or cylindrical shape, or any other suitable shape or configuration. The light guide feature  4214  may be a lens or may include lens elements (e.g., Fresnel lens elements), or it may be a rounded bump (e.g., a convex semicircular protrusion). The light guide feature  4214  may be configured to direct light into the keycap  4202 . 
     The keycap  4202  may include a body portion  4205  formed from or including a light-transmissive material that acts as a light guide or light pipe. The body portion  4205  may define a recess  4216  that receives the light guide feature  4214  therein. The computing device  4200  may be configured so that the light guide feature  4214  is at least partially received in the recess  4216  when the key mechanism is unactuated or undepressed, as shown in  FIG. 42A . Accordingly, light may exit the light guide feature  4214  through surfaces that overlap or face surfaces of the recess  4216 , and enter the body portion  4205  via the overlapping or facing surfaces, as illustrated by the light paths  4220 ,  4218 . (In other configurations, the light guide feature  4214  is not received in the recess  4216  when the key is undepressed.) 
     The keycap  4202  may also include a mask  4208  defining a top opening  4215  and side openings  4217 . The body portion  4205  may direct light through the body portion  4205  and out of the top and side openings  4215 ,  4217 , as described herein. For example, the mask  4208  may include reflective materials to assist in the reflection and/or direction of light through the body portion  4205 , as described herein (e.g., with respect to  FIGS. 39B and 41B ). The light paths  4218 ,  4220  indicate example light paths through the body portion  4205  and out of the top and side openings  4215 ,  4217 . These light paths may illuminate a glyph in the keycap  4202  and the space between keys of a keyboard, for example. 
       FIG. 42B  shows the computing device  4200  when the keycap  4202  is in a depressed or actuated state. The light guide feature  4214  is received further in the recess  4216  as compared to the undepressed or unactuated state. The light guide feature  4214  and the recess  4216  may be configured so that the intensity and/or amount of light emitted through the top and side openings  4215 ,  4217  does not change substantially when the key is actuated. In other cases, they may be configured so that the intensity and/or amount of light does change between actuated and unactuated states. For example, when the key is actuated, the intensity and/or amount of light exiting the side openings  4217  may increase, providing a visual indication that the key has been actuated. 
       FIG. 42C  depicts a partial cross-sectional view of another example computing device with an illuminated keyboard, viewed along section J-J in  FIG. 13A . In particular,  FIG. 42C  depicts a computing device  4229  in which a portion of a top case acts as a light guide or light pipe to direct light into a body of a keycap of a key mechanism, and includes a guide and/or support for the keycap.  FIG. 42C  shows the key mechanism in an undepressed or unactuated state. 
     The computing device  4229  includes a keycap  4222  (an interface member), a top case  4224 , a light guide support  4226 , and a spring member  4228 . The top case  4224  may be the same as, or similar to, the analogous components described above with respect to  FIGS. 34A-35B . The computing device  4229  also includes a light source  4212  positioned below the top case  4224 . The light source  4212  may be mounted to a substrate such as a circuit board  4210  (e.g., a flex circuit). The light source  4212  and the circuit board  4210  are described above with respect to  FIGS. 42A-42B . 
     The light source  4212  directs light into a light guide support  4226  formed into or coupled to the top case  4224 . The light guide support  4226  may be a protrusion having a square or cylindrical shape, or any other suitable shape or configuration. The light guide support  4226  may be a lens or may include lens elements (e.g., Fresnel lens elements). The light guide support  4226  may be configured to direct light into the keycap  4222 . 
     The keycap  4222  may include or be formed from a light-transmissive material that acts as a light guide or light pipe, and may include masked and unmasked regions (e.g., defining glyph openings, side openings, etc.), reflective regions, and the like, as described above with respect to the keycap  4202 . The keycap  4222  may define a recess  4234  that receives the light guide support  4226  therein. Accordingly, light may exit the light guide support  4226  through surfaces that overlap or face surfaces of the recess  4234 , and enter the keycap  4222  via the overlapping or facing surfaces, as illustrated by the light paths  4230 ,  4232 . 
     The light guide support  4226  may engage the recess  4234  of the keycap  4222  to support and guide the keycap  4222  relative to the top case  4224 . For example, surfaces of the recess  4234  may contact surfaces of the light guide support  4226  to help maintain a lateral position of the keycap  4222  relative to the top case  4224  (e.g., in plane with an interface surface of the keycap  4222 ), and may slide against the surfaces of the light guide support  4226  when the key is actuated, thus providing a substantially linear actuation travel of the keycap  4222 . 
     The spring member  4228  is positioned on the light guide support  4226  and in the recess  4234 . The spring member  4228  biases the keycap  4222  towards an unactuated or undepressed state. The spring member  4228  may also provide a tactile and optionally audible feedback when the keycap  4222  is actuated. In particular, the spring member  4228  may produce a tactile response when the keycap  4222  is depressed. The tactile response may be represented or defined by a particular force response curve, as described above with respect to  FIGS. 33A-33B . The spring member  4228  may be any suitable spring member, such as a coil spring, a rubber dome, a collapsible metal dome, an elastomer member, magnets (e.g., magnets configured to repel one another), or the like. 
       FIGS. 42A-42C  show a light source  4212  positioned below the top case directly below a light guide feature. In other example computing devices, however, it may be positioned elsewhere. For example, the light source  4212  may be offset from the light guide feature. As another example, one light source may illuminate multiple keys. In such cases, the planar portion of the top case may itself act as a light guide to direct light through the top case and into light guide features of multiple key mechanisms. 
     Support mechanisms (e.g., for movably supporting a keycap relative to a base plate) in some conventional keyboards and/or computing devices may be positioned in or below an opening in a top case to couple to an interior component of the computing device. Where a continuous top case is used, as described herein, there are no openings that allow access to the interior of the computing device from the top of the top case. Accordingly, support mechanisms may be mounted directly to the top case, as described below with respect to  FIGS. 43A-44D . 
       FIGS. 43A-43C  depict cross-sectional views of an example key  4300  at various stages of assembly to a top case of a computing device. The cross-sectional views may correspond to a view of a computing device along section J-J in  FIG. 13A . 
     In particular,  FIG. 43A  depicts an exploded view of a key  4300  above a top case  4302 . The top case  4302  may define a continuous top surface (e.g., lacking openings for keyboards, keys, trackpads, buttons, etc.), and may be formed from glass, ceramic, plastic, or any other suitable material, as described herein. While the unassembled, exploded key  4300  is shown above the top case  4302 , this is merely to show the components and relative positioning of the components, and may not correspond to any actual positioning during an assembly process. 
     The key  4300  includes a keycap  4304  (which may be similar in structure, material, function, etc., to any of the keycaps described herein), a base structure  4314 , a hinge mechanism  4308 , and a spring member  4307 . The keycap  4304  includes first retention features  4306  that couple to second retention features  4310  (e.g., pins) on the hinge mechanism  4308 . The first retention features  4306  may have any shape or configuration that retains the keycap  4304  to the hinge mechanism  4308  while allowing the second retention features  4310  to rotate and/or slide during actuation of the key (if necessary or desirable). 
     The hinge mechanism  4308  may also include third retention features  4312  (e.g., pins) that couple to fourth retention features  4316  formed in the base structure  4314 . The fourth retention features  4316  may be channels, recesses, openings, grooves, or other features that receive the third retention features or pins  4312  therein. Where the fourth retention features  4316  are recesses, as shown, they may include an opening along one edge to allow the third retention features  4312  to slide into the recesses. The third retention features  4312  may be retained in the recesses by walls or ridges that surround and/or define the recesses and hold the third retention features  4312  captive against the top case  4302  when the base structure  4314  is attached to the top case  4302 . 
     The spring member  4307  may be attached to the base structure  4314  and may be configured to contact the keycap (or any other part of the key  4300 ) to bias the keycap towards an unactuated or undepressed state. The spring member  4307  may have any shape or configuration, such as a dome, a coil spring, a leaf spring, a layer of compliant material, and may be formed from or include any suitable material, such as metal, rubber, foam, plastic, or the like. 
     The base structure  4314  may include first alignment features  4318  that mechanically engage with second alignment features  4320  on the top case  4302 . For example, the first alignment features  4318  may be pins and the second alignment features  4320  may be recesses (e.g., blind holes) formed in the top case  4302 . In some cases, the first alignment features  4318  may be recesses and the second alignment features  4320  may be pins or protrusions. Other types of alignment features may also be used. The first and second alignment features  4318 ,  4320  may aid in positioning and securing the keys of a keyboard (e.g., the key  4300 ) on the top case  4302 . For example, the second alignment features  4320  may be located with a high dimensional accuracy and/or tolerance such that the operation of applying a base structure  4314  to the top case  4302  does not need to be as accurate. More particularly, the second alignment features  4320  act as a physical and optionally an optical guide to correctly position the base structure  4314  on the top case  4302 . As such, some degree of error in the application of the key  4300  will be corrected for or eliminated once the first and second alignment features  4318 ,  4320  are engaged with one another. 
     The first and second alignment features  4318 ,  4320  may also act as retention features. For example, the first and second alignment features  4318 ,  4320  may have complementary shapes (e.g., protrusions and recesses or undercuts) that physically retain the features together. As another example, the first and second alignment features  4318 ,  4320  may be bonded together with an adhesive, such as an epoxy, cyanoacrylate, or any other suitable bonding agent. Staking (e.g., heat staking) may be used to mechanically engage the first alignment features  4318  with the second alignment features  4320 . In such cases the second alignment features  4320  may be through holes or blind holes. 
     As shown in  FIG. 43B , the key  4300  may be assembled prior to being attached to the top case  4302 . The components of the key  4300  may be configured so that, in an assembled state, the components are held captive as a single structure. This may allow the entire key  4300  to be applied to the top case  4302  in an assembled state, which may reduce assembly and manufacturing time, expense, complexity, or the like. 
       FIG. 43C  depicts the key  4300  attached to the top case  4302 . The first alignment features  4318  are engaged with the second alignment features  4320 , thereby aligning and optionally securing the key  4300  to the top case  4302 . The base structure  4314  may also be secured to the top case  4302  using an adhesive or other bonding agent between a top surface of the top case  4302  and a bottom surface of the base structure  4314 . Suitable bonding agents may include HSA, PSA, cyanoacrylate, epoxy, or the like. 
       FIGS. 44A-44D  depict cross-sectional views of an example key  4400  at various stages of assembly to a top case of a computing device. The cross-sectional views may correspond to a view of a computing device along section J-J in  FIG. 13A . 
     The key  4400  in  FIGS. 44A-44D  is similar to the key  4300  except that it includes a different base portion. In particular, the key  4400  includes the keycap  4304 , the hinge mechanism  4308 , and the spring member  4307 . The keycap  4304  includes the first retention features  4306 , and the hinge mechanism  4308  includes the second and third retention features  4310 ,  4312 . The hinge mechanism  4308  movably couples the keycap  4304  to a base structure  4404 . 
     The base structure  4404  includes fourth retention features  4406  that receive and engage the third retention features  4312 , and retain the hinge mechanism  4308  to the base structure  4404 . The fourth retention features  4406  may lack the opening that is included in the fourth retention features  4316  (e.g., to allow pins to slide freely into the fourth retention features  4316 ), as the key  4400  may be assembled in a way that renders the openings superfluous. 
     The base structure  4404  may have a substantially planar or featureless bottom surface, and the top case  4402  may have a substantially planar or featureless top surface. For example, the base structure  4404  may lack the first alignment features that are on the bottom surface of the base structure  4314  in  FIGS. 43A-43C , and the top case  4402  may lack the second alignment features that are on the top case  4302  in  FIGS. 43A-43C . Like the base structure  4314  and top case  4302 , however, the base structure  4404  and the top case  4402  may be attached to one another with a suitable bonding agent, such as HSA, PSA, cyanoacrylate, epoxy, or the like. 
     Where there are no physical alignment features to aid in the alignment of the key on the top case, the key may be assembled as shown through  FIGS. 44A-44D . In particular, the base structure  4404  may be attached to the top case  4402  before the base structure  4404  is assembled with the other components of the key  4400 , as shown in  FIG. 44B . Once the base structure  4404  is attached to the top case  4402 , the spring member  4307  may be positioned on the base structure  4404  and the hinge mechanism  4308  may be coupled to the keycap  4304 , as shown in  FIG. 44C . The hinge mechanism  4308  may then be coupled to the base structure  4404  to complete the key  4400 , as shown in  FIG. 44D . 
       FIGS. 43A-44D  depict states of assembly for several example keys. However, the keys shown in these figures may be assembled in manners and using operations different than those shown. Also, different keys may be assembled according to the operations shown in these figures. 
       FIGS. 45A-46  depict cross-sectional views of additional example keys that may be coupled to a top case or a keyboard accessory, as described herein. The keys depicted in  FIGS. 45-46  may incorporate any of the concepts, components, or techniques described herein. For example, any of the keycaps, keycap masking structures, illumination techniques, key make sensing techniques, etc., may be used in conjunction with the keys depicted in  FIGS. 45-46 . 
     With reference to  FIG. 45A , a key  4500  may include a keycap  4504 , a scissor mechanism  4506 , and a base  4508 . The scissor mechanism  4506  may include multiple members pivotally coupled to one another and coupled to the base  4508  and the keycap  4504  to movably couple the keycap  4504  to the base  4508 , and thus the top case  4502  (which may be a light-transmissive top case, as described herein). The base  4508  may be coupled to the top case  4502  in any suitable way, such as via adhesive, ultrasonic welding/bonding, heat staking, etc. The base  4508  and the top case  4502  may include alignment features, such as the alignment features  4318 ,  4320 , described with respect to  FIGS. 43A-43C . 
     The key  4500  may also include a spring member  4510  attached to the base  4508  and configured to bias the keycap  4504  towards an unactuated or undepressed state. The spring member  4510  may have any shape or configuration, such as a dome, a coil spring, a leaf spring, or a layer of compliant material, and may be formed from or include any suitable material, such as metal, rubber, foam, plastic, or the like. 
     The key  4500  may be completely assembled prior to being coupled to the top case  4502 . For example, the keycap  4504 , scissor mechanism  4506 , spring member  4510 , and base  4508  may be assembled together, and thereafter coupled to the top case  4502 . In other cases, the base  4508  may be attached to the top case  4502  before the key  4500  is completely assembled (e.g., the keycap  4504 , scissor mechanism  4506 , and/or spring member  4510  may be coupled to the base  4508  after the base  4508  is coupled to the top case  4502 ). 
     With reference to  FIG. 45B , a key  4520  may include a keycap  4524 , a hinge mechanism  4526 , and a base structure  4528 . The hinge mechanism  4526  may include a first wing  4530  that is pivotally coupled to both the base structure  4528  and the keycap  4524 , and includes a slot  4532  in the end of the first wing that is proximate the base structure  4528  and a complementary end of a second wing  4534 . The second wing  4534  may also be pivotally coupled to both the base structure  4528  and the keycap  4524 , and includes a protrusion  4536  at the end of the second wing  4534  that is proximate the base structure  4528  and the complementary end of a first wing  4530 . The protrusion  4536  may be positioned in the slot  4532  to mechanically engage the first and second wings  4530 ,  4534 . The slot and protrusion  4532 ,  4536  may be configured to substantially synchronize the motions of the first and second wings  4530 ,  4534  when the key is actuated, and may generally help maintain the keycap  4524  in a substantially flat configuration when it is being pressed, even if the force applied to the keycap  4524  is not centered over the middle of the keycap  4524 . 
     The slot and protrusion  4532 ,  4536  may also be shaped so that the protrusion  4536  can slide within the slot  4532  during key actuation to prevent binding or other physical interference that may increase the actuation force or otherwise interfere with the action of the key. For example, as shown in  FIG. 45B , both the first and second wings  4530 ,  4534  are attached to the keycap  4524  via clips  4538  and pins  4540  that allow rotation of the pins  4540  within the clips  4538 , but generally does not allow lateral movement (e.g., left-to-right, as shown in  FIG. 45B ) of the pins  4540  within the clips  4538 . Accordingly, the slot and the protrusion  4532 ,  4536  (as well as a sliding connection between the second wing  4534  and the base structure  4528 ) provide sufficient freedom of motion to allow the hinge mechanism  4526  to move without binding (e.g., the hinge mechanism  4526  is not over constrained), while the first wing  4530  and the second wing  4534  are mechanically engaged such that they move in a synchronized manner when the key is actuated. Moreover, because the clips  4538  have downward-facing openings, the keycap  4524  may be attached to the hinge mechanism  4526  with a direct downward motion, which may be a simpler and more efficient assembly technique than is possible with keycaps that have a clip and slot configuration (such as that shown in  FIG. 45A ). 
     The key  4520  may also include a spring member  4529  configured to bias the keycap  4504  towards an unactuated or undepressed state. The spring member  4529  may have any shape or configuration, such as a dome, a coil spring, a leaf spring, or a layer of compliant material, and may be formed from or include any suitable material, such as metal, rubber, foam, plastic, or the like. The spring member  4529  may be a dome switch for facilitating electrical detection of key presses. 
       FIG. 46  depicts a key  4600  that includes a keycap  4604 , key web  4608 , and spring member  4610 . The spring member  4610  biases the keycap  4604  towards an unactuated or undepressed state. The spring member  4610  may have any shape or configuration, such as a dome, a coil spring, a leaf spring, or a layer of compliant material, and may be formed from or include any suitable material, such as metal, rubber, foam, plastic, or the like. 
     The keycap  4604  may include flanges  4612  that engage upstops  4614  of the key web  4608  (e.g., portions of the key web  4608  that are adjacent or proximate the opening that receives the keycap  4604 ) to define an upper travel limit of the keycap  4604  and to retain the keycap  4604  to the keyboard. The key web  4608  may be coupled to the top case  4602  in any suitable way, such as via adhesive, ultrasonic welding/bonding, heat staking, etc. The key web  4608  and/or the keycap  4604  may be formed from or include dielectric or nonconductive materials, which may facilitate sensing or detection of key presses, gestures, and other touch-based inputs through the keycap  4604 , key web  4608 , and top case  4602 . 
       FIGS. 47A-47B  depict side views of example keycaps that may be used with any of the keys described herein.  FIG. 47A  depicts a keycap  4700   a  that includes a body portion  4702   a  and retention features  4704 . The body portion  4702   a  may be formed from a first material, and the retention features  4704  may be formed from a second material and attached to the body portion  4702   a . Alternatively, the body portion  4702   a  and the retention features  4704  may be formed from the same material and then attached together. 
     Both the body portion  4702   a  and the retention features  4704  may be formed from dielectric or nonconductive materials. Accordingly, when the keycap  4700   a  is used in a keyboard that uses capacitive touch sensing to sense key makes, or otherwise relies on electromagnetic sensing through the keycap  4700   a , the keycap  4700   a  will not shield objects above the keycap  4700   a  or otherwise prevent the electromagnetic sensing. For example, the body portion  4702   a  and the retention features  4704  may be formed from or include any of glass, ceramic, plastic, sapphire, or any other suitable dielectric material. More particularly, the body portion  4702   a  may be glass and the retention features  4704  may be plastic. As another example, either or both the body portion  4702   a  and the retention features  4704  (or any portion thereof) may be formed from a metal or other conductive material that capacitively or electrically couples to a sensor below a top case to facilitate detection of key makes. 
     The retention features  4704  may be coupled to the body portion  4702   a  in any suitable way. For example, they may be retained mechanically, with clips, screws, complementary mating or engaging features, threads, fasteners, or the like. Alternatively or additionally, they may be bonded together, for example, with an adhesive such as HSA, PSA, cyanoacrylate, epoxy, or the like. 
     The retention features  4704  are shown as clips and channels that are configured to engage pins of a support mechanism (e.g., the hinge mechanism  4308 ,  FIGS. 43A-44D , the scissor mechanism  4506 ,  FIG. 45A , the hinge mechanism  4526 ,  FIG. 45B ) to retain the keycap  4700   a  to the hinge mechanism and allow the hinge mechanism to articulate during a key actuation (e.g., when the key is depressed). While particular configurations of retention features are shown, other types of retention features may also be used. 
       FIG. 47B  depicts a keycap  4700   b  that includes a body portion  4702   b  and an attachment portion  4708  attached to the body portion  4702   b . The attachment portion  4708  includes retention features  4706  extending from a base portion. As described with respect to  FIG. 47A , the attachment portion  4708  and the body portion  4702   b  may be formed from or include any suitable dielectric material that will not shield objects above the keycap  4700   b  from sensors below the keycap  4700   b , such as glass, ceramic, plastic, sapphire, or the like. More particularly, the body portion  4702   b  may be formed from glass and the attachment portion  4708  may be plastic. As another example, either or both the body portion  4702   b  and the attachment portion  4708  (or any portion thereof) may be formed from or include a metal or other conductive material (e.g., conductive coatings, paints, components, etc.) that capacitively or electrically couples to a sensor below a top case to facilitate detection of key makes. 
     The attachment portion  4708  may be monolithic, as shown, such as a single, injection molded component. Alternatively, the retention features  4706  may be formed separately from the base portion and then attached to the base portion to form the attachment portion  4708 . 
     The foregoing description describes computing devices, such as notebook computers, some of which may detect touch inputs anywhere above the top case, including on a keyboard (even a mechanical keyboard) as well as any non-keyboard regions of the top case. Such computing devices may enable new and different ways of interacting with a computing device.  FIGS. 48A-48F  illustrate various techniques for providing inputs to a computing device, as well as example actions that the computing device may perform in response to the inputs. 
       FIG. 48A  depicts a computing device  4800   a  that includes a base portion  4803   a  flexibly coupled (e.g., with a hinge) to a display portion  4801   a . The display portion  4801   a  includes a display  4805   a . The base portion  4803   a  includes a keyboard  4802   a  (which may be a mechanical keyboard or a virtual keyboard, as described above) and a trackpad region  4804   a . Where the keyboard  4802   a  is a mechanical keyboard, it may be positioned at least partially in a rectangular opening in the top case of the base portion  4803   a.    
     The trackpad region  4804   a  may correspond to the non-keyboard region of the top surface of the top case (e.g., all or substantially all of the top surface of the case except for the keyboard  4802   a  and/or a virtual key region). In some cases, the trackpad region  4804   a  also encompasses a virtual key region  4809  that is positioned above the keyboard  4802   a , or the trackpad region  4804   a  may otherwise extend along a top side of the keyboard  4802   a  (e.g., between the keyboard  4802   a  and the display portion  4801   a ) to define a continuous four-sided frame that surrounds or otherwise frames the keyboard  4802   a .  FIG. 48A  shows the trackpad region  4804   a  extending along the top side of the keyboard  4802   a  and encompassing a virtual key region, while  FIGS. 48B-48E  show trackpad regions that do not extend along the top side of the keyboard, and thus extend along three sides of a keyboard (e.g., a left, right, and bottom side of the respective keyboards). Where the trackpad region  4804   a  (or any other trackpad region) encompasses the virtual key region, the trackpad may be used to detect inputs applied to the virtual keys, including selections of virtual keys and/or gesture inputs that are applied to the virtual key region but are not intended as selections of particular virtual keys. In some cases, force and/or touch sensors are positioned under the top case and are configured to detect touch and/or force inputs applied to any portion of the trackpad region  4804   a.    
       FIG. 48A  depicts a finger  4806   a  swiping across the keyboard  4802   a  along a path  4808 . For example, the finger  4806   a  may be swiped along physical keycaps of the keyboard  4802   a  without actuating the keys themselves (e.g., without pressing on the keys sufficiently for the keycap to move or a key input to be registered). Touch sensors within the base portion, such as the touch sensors described above with respect to  FIGS. 18A-18D , detect the user&#39;s finger through the top case and the keycaps (and any other components of a keyboard, such as a fabric or other flexible cover), and may detect properties of the input gesture, such as a starting location, an ending location, and the path between them. 
     The computing device  4800   a  may receive the properties of the input gesture and perform an operation in accordance with the input. For example, the computing device  4800   a  may manipulate or change what is displayed on the display  4805   a  in response to the input.  FIG. 48A , for example, shows a cursor  4812  having been moved along a path  4811  from an initial position  4810  to a second position. The path  4811  may correspond to the path  4808 . For example, the path  4811  may have a direction and length that is the same as or is a scaled representation of the path  4808 . The cursor path  4811  shown in  FIG. 48A  is merely an example of an operation that the computing device  4800   a  may perform in response to the depicted input, and other user interface manipulations or functional operations are also possible. 
       FIG. 48B  depicts a computing device  4800   b , similar to the computing device  4800   a , that includes a base portion  4803   b  with a keyboard  4802   b  and a trackpad region  4804   b , and a display portion  4801   b  with a display  4805   b . In  FIG. 48B , a finger  4806   b  has swiped on the base portion  4803   b  along a path  4814  that begins on the keyboard  4802   b  and extends into the trackpad region  4804   b.    
     As noted above, the computing device  4800   b  may include one or more touch sensors below both the keyboard  4802   b  and the trackpad region  4804   b . These touch sensors may be programmatically or physically integrated such that gestures and other inputs can span these regions without interruption and cause the computing device to produce a single, uninterrupted output. For example, as shown in  FIG. 48B , a cursor  4818  displayed on the display  4805   b  may move from an initial position  4816  along a path  4817  to a second position. The path  4817  may correspond to (e.g., it may be the same as or a scaled representation of) the path  4814 , despite the path  4814  having portions in two physically different input regions of the top case. The cursor path  4817  shown in  FIG. 48B  is merely an example of an operation that the computing device  4800   b  may perform in response to the depicted input, and other user interface manipulations or functional operations are also possible. 
       FIG. 48C  depicts a computing device  4800   c , similar to the computing device  4800   a , that includes a base portion  4803   c  with a keyboard  4802   c  and a trackpad region  4804   c , and a display portion  4801   c  with a display  4805   c .  FIG. 48C  illustrates an example multi-touch gesture that includes inputs applied to both the keyboard  4802   c  and the trackpad region  4804   c . For example, a first finger  4806   c  may be placed on a key of the keyboard  4802   c , while a second finger  4807   c  is swiped away from the first finger  4806   c , across part of the keyboard  4802   c , and into the trackpad region  4804   c . This type of input embodies both multi-touch input detection (e.g., detecting two simultaneous touch inputs) as well as multi-region input detection (e.g., detecting simultaneous touch inputs in different input regions on a top case). 
     The first finger  4806   c  may be actuating a key or it may simply be resting on a key without actuating the key. For example, if the key is a mechanical key, the key may be depressed or undepressed. Also, while the first finger  4806   c  is described above as stationary, it may also be moved across the keyboard  4802   c  at the same time as the second finger  4807   c.    
     The computing device  4800   c  may take any action in response to detecting the input shown in  FIG. 48C . One example, as shown in  FIG. 48C , is changing the size of a user interface element on the display  4805   c . For example, a user interface element  4824  may be resized from an initial size  4822  to a second size, expanding along the path  4823 . The amount and direction of the resizing of the interface element  4824  may correspond to the path  4820  of the input gesture. As noted above, the element resizing shown in  FIG. 48C  is merely an example of an operation that the computing device  4800   c  may perform in response to the depicted input, and other user interface manipulations or functional operations are also possible. 
       FIG. 48D  depicts a computing device  4800   d , similar to the computing device  4800   a , that includes a base portion  4803   d  with a keyboard  4802   d  and a trackpad region  4804   d , and a display portion  4801   d  with a display  4805   d .  FIG. 48D  illustrates an example input gesture that is applied to a portion of the top case that is along a side of the keyboard. For example, a finger  4807   d  is swiped downward along the side of the top case, along input path  4826 . 
     The computing device  4800   d  may take any action in response to detecting the input shown in  FIG. 48D . One example, as shown in  FIG. 48D , is scrolling or moving a user interface element on the display  4805   d . For example, a user interface element  4830 , such as a graphical object (e.g., an image), a document, a web page, or the like, may be moved from an initial position  4828  to a second position along the path  4829 . 
       FIG. 48E  depicts a computing device  4800   e , similar to the computing device  4800   a , that includes a base portion  4803   e  with a keyboard  4802   e  and a trackpad region  4804   e , and a display portion  4801   e  with a display  4805   e .  FIG. 48E  illustrates an example input gesture that is applied to a touch sensitive key of the keyboard  4802   e . The key  4844   e  may be a mechanical key that is associated with a touch sensor, as described in various embodiments herein, or it may be a virtual key region (e.g., an input region on a top case and associated with touch and/or force sensors and haptic output devices). 
     The key  4844   e  (shown as a space bar, though any other key may be used for this or similar input gestures) may be capable of receiving traditional key inputs as well as gesture inputs. More particularly, when a user strikes the key  4844   e  in a conventional typing manner, the computing device  4800   e  may respond in a conventional way (e.g., taking an action that results from selection of the space bar, such as inserting a space in a text input, selecting an on-screen affordance, etc.). When the user applies a touch gesture to the key  4844   e , however, the computing device  4800   e  may perform a different action. For example, as shown in  FIG. 48E , a gesture input such as a user sliding a finger or thumb along a path  4846   e  may result in a user accepting a suggested spelling  4842   e  of a misspelled word  4840   e  in a word processing application or other text input field. 
     Gestures other than the sliding gesture shown may also be used. For example, a user may also be able to slide a finger or thumb along the path  4846   e  in an opposite direction to perform a function (e.g., to decline a proposed spelling correction, to delete a character or word, highlight the previous word, or the like). As another example, a user may be able to slide two fingers or thumbs towards each other (e.g., a pinch gesture), or away from each other (e.g., an unpinch gesture) along the key  4844   e , which may cause a displayed graphical output to be increased or decreased in size (e.g., zoomed out or in). These or other gestures may be used to perform other functions instead of or in addition to those described. For example, a swipe up gesture applied to a letter input key may cause the corresponding capital letter to be input rather than the lower case letter. Similarly, a swipe gesture applied to a shift key may cause the computing device to switch between a foreground and a background application interface (e.g., switching between active applications). Other gestures and functions are also possible. 
       FIG. 48E  describes how gesture inputs, which may be enabled by touch and/or force sensors associated with an electronic device, may be used to improve the speed and ease with which words and text may be inputted into a device. The integrated interface system described herein may also facilitate other techniques for improving text input to a computing device. For example, in some cases, a force sensor may detect or determine an input at a location that is proximate to multiple neighboring key regions. In such cases, a touch sensor may be used to determine a more accurate location for the centroid of the touch input, which may be used to determine which of the neighboring key regions was the likely target of the user. For example, if a user touches an area that is close to the border between the “f” and “d” keys of a keyboard, it may be ambiguous which key was the user&#39;s target based on force sensor data alone. The touch sensor may be used to break the tie between the “f” and “d” keys based on the centroid of the touch input. If the centroid is closer to the “f” key, then the computing device may register the input as a selection of the “f” key and ignore the “d” key (and vice versa). This tie-break process may be used without reference to any prior inputs, and as such may allow for more accurate typing inputs without regard to spelling and/or grammar analysis to determine a user&#39;s intended target key. This may improve on existing methods whereby mistyped words are essentially only correctable by the computing device based on spelling and/or grammar of the inputs, and not based on the actual physical inputs. More particularly, a device with only a conventional mechanical keyboard may detect the string “cvomputer” and recommend that it be replaced with “computer,” while the tie-break functionality enabled by the touch and force sensing system can determine, before the word is even completed, that the user intended to select only the “c” key. This may provide more accurate typing, as certain words might otherwise not be identifiable by a spelling or grammar based system. For example, if a user inputs a string such as “cvomnputrer,” the word may not be similar enough to “computer” for a device to suggest the correct spelling. Because the tie-break system described above can determine which keys were actually intended to be selected, the incorrect string may be avoided in the first place (e.g., the incorrect letters would have been ignored from the outset). 
     Of course, a computing device may use prior inputs to help break ties and/or determine likely intended inputs. For example, if a user has typed the letters “keyboar”, a force input that may be interpreted as a selection of either an “f” or a “d” key may be determined to be the “d” based on the fact that it correctly spells a word (and optionally because the centroid of the input was detected closer to the “d” than the “f” key). 
       FIG. 48F  depicts a computing device  4800   f , similar to the computing device  4800   a , that includes a base portion  4803   f  and a display portion  4801   f  with a display  4805   f . The base portion  4803   f  may include a display in the base portion  4803   f  that is visible through a top case (e.g., a transparent glass or plastic top case) of the base portion  4803   f . The display in the base portion  4803   f  may display affordances on the base portion  4803   f  with which a user can interact. As shown, the affordances include a button array  4834   f  and a rotatable dial  4836   f . A user can interact with both of the affordances either individually or simultaneously to provide varying types of inputs and cause the computing device  4800   f  to perform varying functions. For example,  FIG. 48F  illustrates the display  4805   f  showing a three dimensional model of an object, and the affordances may be used to manipulate the view of the object. For example, a user selection of a button in the button array  4834   f , as shown in  FIG. 48F , may cause the computing device  4800   f  to interpret an input to the rotatable dial  4836   f  in one of various possible ways. More particularly, the buttons of the button array  4834   f  may determine whether inputs to the rotatable dial  4836   f  cause the three dimensional model to rotate horizontally, rotate vertically, be zoomed in or out, or the like. As shown in  FIG. 48F , the selection of the particular button and the rotation of the rotatable dial  4836   f  results in a displayed object being rotated or otherwise manipulated from an initial orientation  4831   f  to a final orientation  4832   f . Other types of affordances may also be displayed, and other functions may be performed in response to user manipulations of the affordances (e.g., touch and/or force inputs applied to the displayed affordances). 
     In  FIGS. 48A-48F , fingers are shown as providing the touch inputs. It will be understood that other objects or implements may be used instead of or in addition to a finger, such as a stylus or any other suitable object that is detectable by the touch sensors within the computing devices. Moreover, the computing devices may take other actions or perform other functions in response to the inputs shown in  FIGS. 48A-48F , such as changing a volume of an audio output, changing the brightness or any other output property of the display, moving a different user interface element (e.g., a slider bar for a media playback application) across the display, or the like. 
     As described herein, a top case for an computing device may be formed of or include a dielectric material, such as glass, plastic, ceramic, or the like. The dielectric and/or nonconductive properties of such material may allow various types of components that are below the top case to effectively communicate through the top case. For example, electromagnetic signals and/or fields may be able to pass through the top case to facilitate communication between devices, wireless power transfer (e.g., inductive charging), optical and/or capacitive sensing, and the like. 
       FIG. 49A  depicts an example computing device  4900   a  that interfaces with external objects through a top case. The computing device  4900   a  includes a base portion  4903   a  flexibly coupled (e.g., with a hinge) to a display portion  4901   a . The display portion  4901   a  includes a display  4905   a . The base portion  4903   a  includes a keyboard  4902   a  (which may be a mechanical keyboard or a virtual keyboard, as described above) and a trackpad region  4904   a . The trackpad region  4904   a  may correspond to the non-keyboard region of the top surface of the top case (e.g., all or substantially all of the top surface of the case except for the keyboard  4902   a  and/or a virtual key region). 
     The device  4900   a  may include various components within the base portion  4903   a  that are configured to interact with external objects through the top case of the base portion  4903   a . For example, the device  4900   a  includes biometric sensors  4912   a , a fingerprint sensor  4910   a , and a wireless charger  4914   a . The biometric sensors  4912   a  may be positioned where a user typically rests his or her palms or wrists when typing on the keyboard  4902   a . The biometric sensors  4912   a  may be configured to detect biometric information about the user through the top case. For example, the biometric sensors  4912   a  may detect palm- or wrist-prints, detect a user&#39;s heart rate, blood oxygenation levels, temperature, and the like. Such information may be used for authentication purposes, to determine the user&#39;s hand position relative to the device, and/or to record health data for the user to track. As noted, the biometric sensors  4912   a  may use any suitable sensing techniques, such as optical sensors (e.g., photoplethysmographs, cameras, etc.), capacitive sensors, or the like. The biometric sensors  4912   a  may also include facial-recognition sensors, which may include cameras, lenses, projectors (e.g., microdot projectors), infrared sensors, and the like, which may also communicate through the top case to provide facial recognition functionality. In some cases, the regions associated with the biometric sensors  4912   a  may remain touch and/or force sensitive, as described herein. 
     The computing device  4900   a  may also include a fingerprint sensor  4910   a . The fingerprint sensor  4910   a  may detect a user&#39;s fingerprint to authenticate the user to the device  4900   a . The fingerprint sensor  4910   a  may use any suitable sensing technology, including optical, capacitive, inductive, ultrasonic and/or acoustic, or the like. 
     The computing device  4900   a  may also include a wireless charger  4914   a  within the base portion  4903   a . The wireless charger  4914   a  may be configured to transfer power to an external device  4916   a  (e.g., a smartphone, a music player, or the like), or receive power from an external source (e.g., a charger that is coupled to a power source, a portable battery, etc.). The wireless charger  4914   a  may use inductive coils to transmit and/or receive power between two devices. As noted above, the dielectric properties of the top case may allow electromagnetic fields to pass therethrough with sufficiently little attenuation to allow inductive coupling between two coils. 
     The biometric sensors  4912   a , fingerprint sensor  4910   a , and wireless charger  4914   a  may be at any suitable position in the base portion  4903   a  or the display portion  4901   a . Moreover, the biometric sensors  4912   a , fingerprint sensor  4910   a , and wireless charger  4914   a  may be associated with a graphic, border, or other visual indicator of its location, allowing users to easily and quickly locate the components. The visual indicators may be defined by microperforations in a mask layer, which may be lit from below to define an illuminated visual indicator, as described above. 
       FIG. 49B  depicts an example computing device  4900   b  that is configured to communicate through the top case to a removable peripheral input device. The computing device  4900   b  includes a base portion  4903   b  flexibly coupled (e.g., with a hinge) to a display portion  4901   b . The display portion  4901   b  includes a display  4905   b . The base portion  4903   b  includes a keyboard  4902   b  (which may be a mechanical keyboard or a virtual keyboard, as described above) and a trackpad region  4904   b . The trackpad region  4904   b  may correspond to the non-keyboard region of the top surface of the top case (e.g., all or substantially all of the top surface of the case except for the keyboard  4902   b  and/or a virtual key region). 
     The computing device  4900   b  may include in the base portion  4903   b  a connection region  4919   b , which may be configured to receive thereon a peripheral input unit  4924   b  (or any other suitable electronic device). As shown, the peripheral input unit  4924   b  is a joystick that may be used, for example, to manipulate displays of three dimensional objects, provide input for gaming applications, navigate user interfaces, or the like. 
     The computing device  4900   b  may further include alignment components  4920   b  within the base portion  4903   b . The alignment components  4920   b , which may be magnets or magnetic materials, may be attracted to corresponding magnets or magnetic materials in the peripheral input unit  4924   b  to properly align the peripheral input unit  4924   b  relative to the base portion  4903   b  and otherwise retain the peripheral input unit  4924   b  to the base portion  4903   b . The computing device  4900   b  may also include a wireless communication module  4922   b , which may include an antenna for transmitting and receiving wireless signals as well as associated processors and circuitry to facilitate communications. As shown, the wireless communication module  4922   b  is positioned under the peripheral input unit  4924   b , but it may be positioned elsewhere. When the peripheral input unit  4924   b  is attached to the base portion  4903   b , it may communicate with the computing device  4900   b  via the wireless communication module  4922   b  to provide input signals to the computing device  4900   b . The computing device  4900   b  may also include sensors that detect when the peripheral input unit  4924   b  is attached to the top case at the connection region  4919   b . The computing device  4900   b  may automatically initiate communications with and/or begin accepting inputs from the peripheral input unit  4924   b  once its presence is detected on the connection region  4919   b.    
       FIG. 50  depicts an example schematic diagram of an electronic device  5000 . By way of example, device  5000  of  FIG. 50  may correspond to the computing device  100  shown in  FIG. 1A . To the extent that multiple functionalities, operations, and structures are disclosed as being part of, incorporated into, or performed by the device  5000 , it should be understood that various embodiments may omit any or all such described functionalities, operations, and structures. Thus, different embodiments of the device  5000  may have some, none, or all of the various capabilities, apparatuses, physical features, modes, and operating parameters discussed herein. 
     As shown in  FIG. 50 , the device  5000  includes one or more processing units  5002  that are configured to access a memory  5004  having instructions stored thereon. The instructions or computer programs may be configured to perform one or more of the operations or functions described with respect to the device  5000 . For example, the instructions may be configured to control or coordinate the operation of one or more displays  5020 , one or more touch sensors  5006 , one or more force sensors  5008 , one or more communication channels  5010 , and/or one or more haptic feedback devices  5012 . 
     The processing units  5002  of  FIG. 50  may be implemented as any electronic device capable of processing, receiving, or transmitting data or instructions. For example, the processing units  5002  may include one or more of: a microprocessor, a central processing unit (CPU), an application-specific integrated circuit (ASIC), a digital signal processor (DSP), or combinations of such devices. As described herein, the term “processor” is meant to encompass a single processor or processing unit, multiple processors, multiple processing units, or any other suitably configured computing element or elements. 
     The memory  5004  can store electronic data that can be used by the device  5000 . For example, a memory can store electrical data or content such as, for example, audio and video files, documents and applications, device settings and user preferences, timing and control signals or data for the various modules, data structures or databases, and so on. The memory  5004  can be configured as any type of memory. By way of example only, the memory can be implemented as random access memory, read-only memory, Flash memory, removable memory, or other types of storage elements, or combinations of such devices. 
     The touch sensors  5006  may detect various types of touch-based inputs and generate signals or data that are able to be accessed using processor instructions. The touch sensors  5006  may use any suitable components and may rely on any suitable phenomena to detect physical inputs. For example, the touch sensors  5006  may be capacitive touch sensors, resistive touch sensors, acoustic wave sensors, or the like. The touch sensors  5006  may include any suitable components for detecting touch-based inputs and generating signals or data that are able to be accessed using processor instructions, including electrodes (e.g., electrode layers), physical components (e.g., substrates, spacing layers, structural supports, compressible elements, etc.), processors, circuitry, firmware, and the like. The touch sensors  5006  may be used in conjunction with various input mechanisms to detect various types of inputs. For example, the touch sensors  5006  may be used to detect touch inputs (e.g., gestures, multi-touch inputs, taps, etc.), keyboard inputs (e.g., actuations of mechanical or virtual keys), and the like. The touch sensors  5006  may be integrated with or otherwise configured to detect touch inputs applied to a top case of a computing device (e.g., the top case  112  discussed above). The touch sensors  5006  may operate in conjunction with the force sensors  5008  to generate signals or data in response to touch inputs. 
     The force sensors  5008  may detect various types of force-based inputs and generate signals or data that are able to be accessed using processor instructions. The force sensors  5008  may use any suitable components and may rely on any suitable phenomena to detect physical inputs. For example, the force sensors  5008  may be strain-based sensors, piezoelectric-based sensors, piezoresistive-based sensors, capacitive sensors, resistive sensors, or the like. The force sensors  5008  may include any suitable components for detecting force-based inputs and generating signals or data that are able to be accessed using processor instructions, including electrodes (e.g., electrode layers), physical components (e.g., substrates, spacing layers, structural supports, compressible elements, etc.), processors, circuitry, firmware, and the like. The force sensors  5008  may be used in conjunction with various input mechanisms to detect various types of inputs. For example, the force sensors  5008  may be used to detect clicks, presses, or other force inputs applied to a trackpad, a keyboard, a virtual key region, a touch- or force-sensitive input region, or the like, any or all of which may be located on or integrated with a top case of a computing device (e.g., the top case  112  discussed above). The force sensors  5008  may be configured to determine a magnitude of a force input (e.g., representing an amount of force along a graduated scale, rather than a mere binary “force/no-force” determination). The force sensors  5008  and/or associated circuitry may compare the determined force magnitude against a threshold value to determine what, if any, action to take in response to the input. As described herein, force thresholds may be selected dynamically or otherwise changed based on the location of the input, whether a user&#39;s palms are detected resting on the top case, or any other suitable factor(s). The force sensors  5008  may operate in conjunction with the touch sensors  5006  to generate signals or data in response to touch- and/or force-based inputs. 
     The touch sensors  5006  and the force sensors  5008  (which may also be referred to as touch and force sensing systems) may be considered part of a sensing system  5009 . The sensing system  5009  may include touch sensors alone, force sensors alone, or both touch and force sensors. Moreover, the sensing system  5009  may provide touch sensing functions and/or force sensing functions using any configuration or combination of hardware and/or software components, systems, subsystems, and the like. For example, some force sensing components and associated circuitry may be capable of determining both a location of an input as well as a magnitude of force (e.g., a non-binary measurement) of the input. In such cases, a distinct physical touch-sensing mechanism may be omitted. In some examples, physical mechanisms and/or components may be shared by the touch sensors  5006  and the force sensors  5008 . For example, an electrode layer that is used to provide a drive signal for a capacitive force sensor may also be used to provide the drive signal of a capacitive touch sensor. In some examples, a device includes functionally and/or physically distinct touch sensors and force sensors to provide the desired sensing functionality. 
     The device  5000  may also include one or more haptic devices  5012 . The haptic device  5012  may include one or more of a variety of haptic technologies such as, but not necessarily limited to, rotational haptic devices, linear actuators, piezoelectric devices, vibration elements, and so on. In general, the haptic device  5012  may be configured to provide punctuated and distinct feedback to a user of the device. More particularly, the haptic device  5012  may be adapted to produce a knock or tap sensation and/or a vibration sensation. Such haptic outputs may be provided in response to detection of touch- and/or force-based inputs, such as detection of key actuations on a virtual or mechanical keyboard, detection of force inputs on a trackpad region, or the like. Haptic outputs may be local or global, as described herein, and may be imparted to a user through various physical components, such as a top case of a notebook computer, as described herein. 
     The one or more communication channels  5010  may include one or more wireless interface(s) that are adapted to provide communication between the processing unit(s)  5002  and an external device. In general, the one or more communication channels  5010  may be configured to transmit and receive data and/or signals that may be interpreted by instructions executed on the processing units  5002 . In some cases, the external device is part of an external communication network that is configured to exchange data with wireless devices. Generally, the wireless interface may include, without limitation, radio frequency, optical, acoustic, and/or magnetic signals and may be configured to operate over a wireless interface or protocol. Example wireless interfaces include radio frequency cellular interfaces, fiber optic interfaces, acoustic interfaces, Bluetooth interfaces, infrared interfaces, USB interfaces, Wi-Fi interfaces, TCP/IP interfaces, network communications interfaces, or any other conventional communication interfaces. 
     As shown in  FIG. 50 , the device  5000  may include a battery  5014  that is used to store and provide power to the other components of the device  5000 . The battery  5014  may be a rechargeable power supply that is configured to provide power to the device  5000  while it is being used by the user. 
     The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of the specific embodiments described herein are presented for purposes of illustration and description. They are not targeted to be exhaustive or to limit the embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings. Also, when used herein to refer to positions of components, the terms above and below, or their synonyms, do not necessarily refer to an absolute position relative to an external reference, but instead refer to the relative position of components with reference to the figures. 
     Moreover, the foregoing figures and descriptions include numerous concepts and features, which may be combined in numerous ways to achieve numerous benefits and advantages. Thus, features, components, elements, and/or concepts from various different figures may be combined to produce embodiments or implementations that are not necessarily shown or described together in the present description. Further, not all features, components, elements, and/or concepts shown in a particular figure or description are necessarily required in any particular embodiment and/or implementation. It will be understood that such embodiments and/or implementations fall within the scope of this description.

Metadata:
Filing Date: 20180328
Publication Date: 20201222
Grant Date: 20201222
Priority Date: 20170329
Inventors: LIGTENBERG, CHRISTIAAN A.
DEGNER, BRETT W.
HOPKINSON, Ron A.
HUSSAIN, ASIF
MATHEW, DINESH C.
SILVANTO, MIKAEL M.
ZHANG, CHANG
GAO, ZHENG
CAO, ROBERT Y.
HENDREN, KEITH J.
LANCASTER-LAROCQUE, SIMON R.
Assignee: APPLE INC
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Family ID: 62063172