Patent Publication Number: US-2023136768-A1

Title: Electronic Devices With Display and Touch Sensor Structures

Description:
This application is a continuation of U.S. patent application Ser. No. 17/224,999, filed Apr. 7, 2021, which is a continuation of U.S. patent application Ser. No. 15/159,074, filed May 19, 2016, now U.S. Pat. No. 10,983,626, which claims the benefit of U.S. provisional patent application No. 62/171,634, filed Jun. 5, 2015, all of which are hereby incorporated by reference herein in their entireties. 
    
    
     BACKGROUND 
     This relates generally to electronic devices, and, more particularly, to electronic devices with touch sensors and displays. 
     Electronic devices such as cellular telephones, tablet computers, watches, laptop computers, and other devices often contain displays. Touch sensors may be used to provide displays with the ability to capture touch input from a user. 
     It can be challenging to gather touch input from a user and to display images for a user efficiently. For example, when a user supplies touch input to a touch screen display, the user&#39;s hand may block images that are being displayed on the display. Buttons and other input devices may be used to gather input from a user, but this type of input device may not be as convenient and versatile as a touch sensor. Displays are sometimes not visible from certain directions and may be smaller than desired. 
     It would therefore be desirable to be able to provide electronic devices with enhanced touch sensor and display structures. 
     SUMMARY 
     An electronic device may have an enclosure with walls formed from transparent and opaque materials. Display layers may be mounted under transparent portions of the walls. Touch sensor layers may be mounted under opaque and transparent wall portions. 
     The electronic device may have a front wall and opposing rear wall. Sidewalls may extend between the front and rear wall. The sidewalls may be flat or may be curved. The front wall and portions of sidewalls may be formed from a glass layer or other transparent member. A touch sensor layer and display layer may extend under the front and sidewall portions of the glass layer. A touch sensor layer may also extend under the opposing rear wall. 
     A foldable electronic device may have a flexible transparent wall portion that joins planar transparent walls. Components may be interposed between the transparent planar walls and opaque walls. Display and touch layers may be overlapped by the transparent walls and the transparent flexible wall portion. Additional touch layers may be overlapped by the opaque walls. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of an illustrative electronic device in accordance with an embodiment. 
         FIG.  2    is a schematic diagram of an illustrative electronic device in accordance with an embodiment. 
         FIG.  3    is a cross-sectional side view of an electronic device in accordance with an embodiment. 
         FIG.  4    is a cross-sectional side view of an illustrative electronic device having a vertical sidewall portion in accordance with an embodiment. 
         FIG.  5    is a cross-sectional side view of an illustrative electronic device with a sidewall portion that slopes away from a front device surface in accordance with an embodiment. 
         FIG.  6    is a cross-sectional side view of an illustrative electronic device with a sidewall portion that slopes away from a rear device surface in accordance with an embodiment. 
         FIG.  7    is a cross-sectional side view of an illustrative electronic device with a curved sidewall in accordance with an embodiment. 
         FIG.  8    is a top view of an illustrative display in accordance with an embodiment. 
         FIG.  9    is a top view of an illustrative touch sensor in accordance with an embodiment. 
         FIG.  10    is a cross-sectional side view of a portion of an electronic device with a wall such as an opaque wall and a touch sensor that is attached to an inner surface of the wall in accordance with an embodiment. 
         FIG.  11    is a cross-sectional side view of a portion of an electronic device with an opaque wall having an inner surface on which a touch sensor has been formed as a coating in accordance with an embodiment. 
         FIG.  12    is a cross-sectional side view of a portion of an electronic device with a clear wall having an inner surface on which a touch sensor has been formed as a coating and to which a display layer has been attached using adhesive in accordance with an embodiment. 
         FIG.  13    is a cross-sectional side view of a portion of an electronic device with a clear wall having an inner surface to which a touch sensor layer and display have been attached in accordance with an embodiment. 
         FIG.  14    is a perspective view of an illustrative electronic device of the type that may be provided with display and touch sensor structures in accordance with an embodiment. 
         FIGS.  15 ,  16 , and  17    are cross-sectional side views of illustrative electronic devices with touch sensor and display structures in accordance with an embodiment. 
         FIG.  18    is a perspective view of an illustrative folding electronic device of the type that may be provided with display and touch sensor structures in accordance with an embodiment. 
         FIG.  19    is a perspective view of the electronic device of  FIG.  18    in an unfolded configuration in accordance with an embodiment. 
         FIG.  20    is a cross-sectional side view of an illustrative device of the type shown in  FIGS.  18  and  19    in a folded configuration in accordance with an embodiment. 
         FIG.  21    is a diagram of illustrative equipment that may be used in fabricating electronic devices with touch sensors and display structures in accordance with an embodiment. 
         FIG.  22    is a cross-sectional side view of an illustrative electronic device during fabrication operations in which flexible structures for a display and/or touch sensor are being laminated to the planar and curved inner surfaces of an enclosure wall in accordance with an embodiment. 
         FIGS.  23  and  24    are cross-sectional side views of an illustrative electronic device during fabrication operations in which structures for a display and/or touch sensor are being deposited and patterned on the planar and curved inner surfaces of an enclosure wall in accordance with an embodiment. 
         FIGS.  25  and  26    are cross-sectional side views of an illustrative electronic device during fabrication operations in which structures for a display and/or touch sensor are being fabricated in a planar configuration and then bent to form a wall with curved end portions in accordance with an embodiment. 
         FIG.  27    is a cross-sectional side view of an illustrative electronic device with two flexible portions to allow the device to fold along two respective bend axes in accordance with an embodiment. 
         FIG.  28    is a cross-sectional side view of an illustrative electronic device with three or more flexible portions to allow the device to fold along three or more respective bend axes in accordance with an embodiment. 
         FIG.  29    is a cross-sectional side view of a flexible electronic device hinge region having flexible layers of material that form a hinge in accordance with an embodiment. 
         FIG.  30    is a cross-sectional side view of a flexible electronic device hinge region having a flexible accordion structure in accordance with an embodiment. 
         FIG.  31    is a cross-sectional side view of a flexible electronic device hinge region having mating structural members that rotate with respect to each other about a pivot structure such as a pin to form a hinge in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     An electronic device may be provided with input-output devices to gather input and to provide output to a user. The input-output devices may include touch sensor structures. The electronic device may have control circuits, batteries, and other components that are enclosed within the walls of an enclosure. The walls may have opaque portions and transparent portions. The opaque portions may include opaque plastic, metal, fiber-composite materials and layers of other materials with fibers, ceramic, and other opaque materials and may include transparent material that is coated with one or more opaque layers (e.g., clear glass, clear plastic, sapphire, or other transparent material coated on an inner surface with an opaque masking layer). The transparent wall portions may be formed from clear glass, clear plastic, sapphire, or other transparent materials. 
     Display structures may be mounted behind the transparent portions and may display images for a user. The images may include video, graphics, text, virtual buttons, and other visual content. The touch sensor structures may be mounted behind the transparent portions and behind the opaque portions. The touch sensor structures may have portions that overlap the display structures, thereby forming a touch screen display region on the device. The touch sensor structures may also have portions that do not overlap the display structures and which therefore serve exclusively as touch sensor inputs. 
     Touch sensor structures and display structures may be formed from thin layers of material and may therefore sometimes be referred to touch sensor layers and display layers. The touch sensor and display layers may be formed on rigid substrates such as glass layers and rigid printed circuit board layers and/or may be formed on flexible substrates (e.g., flexible printed circuit material such as flexible layers of polyimide or sheets of other flexible polymer material). In some configurations, touch sensor structures and display structures may be formed as coating layers on the surface of an enclosure wall. Combinations of these approaches may also be used, if desired. 
     A perspective view of an illustrative electronic device of the type that may be provided with touch sensor structures and display structures is shown in  FIG.  1   . Electronic device  10  may be a computing device such as a laptop computer, a computer monitor containing an embedded computer, a tablet computer, a cellular telephone, a media player, or other handheld or portable electronic device, a smaller device such as a wrist-watch device (e.g., a watch with a wrist strap), a pendant device, a headphone or earpiece device, a device embedded in eyeglasses or other equipment worn on a user&#39;s head, or other wearable or miniature device, a television, a computer display that does not contain an embedded computer, a gaming device, a navigation device, an embedded system such as a system in which electronic equipment with a display is mounted in a kiosk or automobile, equipment that implements the functionality of two or more of these devices, or other electronic equipment. In the illustrative configuration of  FIG.  1   , device  10  is a portable device such as a cellular telephone, media player, tablet computer, wrist device, or other portable computing device. Other configurations may be used for device  10  if desired. The example of  FIG.  1    is merely illustrative. 
     In the example of  FIG.  1   , device  10  includes a display such as display  14 . The components of device  10  may be mounted within enclosure walls  12 . Some of enclosure walls  12  such as illustrative front face wall  12 - 6  may be formed from clear glass, clear plastic (e.g., rigid and/or flexible plastic with a clear hard coating such as an inorganic antiscratch layer formed from silicon nitride, metal nitride, titanium nitride, silicon oxide, metal oxide, diamond-like coating material, or other material with abrasion resistance), sapphire, or other transparent material and can therefore serve as covers for display layers. In this context the walls may sometimes be referred to as display cover layers (i.e., wall  12 - 6  may cover a display layer that displays images and that serves as display  14 ). Other portions of enclosure walls  12  may be formed from opaque plastic (e.g., flexible and/or rigid plastic covered with a hard coating layer), metal, or clear material coated with opaque masking material (e.g., an inner layer of black ink). Opaque wall portions of the enclosure for device  10  may sometimes be referred to as housing structures. 
     The display layers of device  10  need not be confined to front wall  12 - 6  of device  10 . In the illustrative configuration of  FIG.  1   , device  10  has six sides: right sidewall  12 - 1 , left sidewall  12 - 2 , top sidewall  12 - 3 , bottom sidewall  12 - 2 , rear wall  12 - 5 , and front wall  12 - 6 . Display layers and touch sensor layers in device  10  can cover some or all of these surfaces. As one example, touch sensor layers may cover all surfaces of device  10  and the display structures of device  10  may be confined to central (“active area”) portion AA of front wall  12 - 6 . As another example, the display for device  10  may cover portion AA on front wall  12 - 6  and the touch sensors for device  10  may cover front wall  12 - 6  including portion AA and may cover opaque (“inactive area”) portions IA at the upper and lower ends of front face  12 - 6 . Yet another example involves wrapping a display around some or all of device  10  (e.g., to cover a strip in the center of device  10  including active area AA, corresponding portions of sidewalls  12 - 1  and  12 - 2 , and some or all of the center of rear face  12 - 5 ). In this type of arrangement, touch sensors may be formed in at least the areas covered with the display structures and may optionally cover other portions of device  10  (e.g., ends  12 - 2  and  12 - 1 , inactive areas IA on front face  12 - 6 , etc.). 
     Openings may be formed in the walls of enclosure  12 . For example, openings such as opening  16  may be formed to accommodate a button, openings such as opening  18  may be formed to accommodate a speaker port, openings such as opening  22  in bottom sidewall  12 - 2  may be formed to accommodate a connector port, and adjacent openings such as openings  20  and  24  may be used to form speaker and microphone ports, respectively (as examples). 
       FIG.  2    is a schematic diagram of device  10 . As shown in  FIG.  2   , electronic device  10  may have control circuitry  30 . Control circuitry  30  may include storage and processing circuitry for supporting the operation of device  10 . The storage and processing circuitry may include storage such as hard disk drive storage, nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory configured to form a solid state drive), volatile memory (e.g., static or dynamic random-access-memory), etc. Processing circuitry in control circuitry  30  may be used to control the operation of device  10 . The processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, baseband processors, power management units, audio chips, application specific integrated circuits, etc. 
     Input-output circuitry in device  10  such as input-output devices  34  may be used to allow data to be supplied to device  10  and to allow data to be provided from device  10  to external devices. Input-output devices  34  may include buttons, joysticks, scrolling wheels, touch pads, key pads, keyboards, microphones, speakers, tone generators, vibrators, cameras, sensors (e.g., ambient light sensors, proximity sensors, magnetic sensors, force sensors, touch sensors such as touch sensors  32 , accelerometers, and other sensors), light-emitting diodes and other status indicators, data ports, displays such as display  14 , etc. A user can control the operation of device  10  by supplying commands through input-output devices  34  and may receive status information and other output from device  10  using the output resources of input-output devices  34 . 
     Touch sensors  32  may be formed using any suitable touch technology. As an example, touch sensors  32  may be formed from one or more patterned layers of capacitive touch sensor electrodes. Other types of touch sensor may be used in device  10  if desired (e.g., touch sensors having touch sensor components such as resistive touch sensor components, acoustic touch sensor components, force-based touch sensor components, light-based touch sensor components, etc.). Touch sensor structures may be transparent and/or may be opaque. For example, touch sensors that are transparent may have transparent touch sensor structures such as capacitive touch screen electrodes that are formed from an array of indium tin oxide electrodes or other transparent conductive electrode structures. If desired, transparent touch sensor structures may have thin metal lines (e.g., nanostructures) that are sufficiently small to be invisible to the eye. Opaque capacitive touch sensors may be formed from opaque capacitive touch sensor electrodes such as metal capacitive touch sensor electrodes. 
     Each display layer for the display(s)  14  in device  10  may include an array of pixels formed from liquid crystal display (LCD) components, an array of electrophoretic pixels, an array of plasma pixels, an array of organic light-emitting diode pixels, an array of discrete light-emitting diodes, an array of electrowetting pixels, or pixels based on other display technologies. 
     Control circuitry  30  may be used to run software on device  10  such as operating system code and applications. During operation of device  10 , the software running on control circuitry  30  may use touch sensors  32  in devices  34  to gather touch sensor input from a user. A user may, for example, supply touch input using one or more fingers and/or other external objects (e.g., a stylus, etc.). The touch input may be supplied to any of the surfaces of device  10  that include touch sensor structures  32  (e.g., walls  12 - 1 ,  12 - 2 ,  12 - 3 ,  12 - 4 ,  12 - 5 , and/or  12 - 6 .). Touch input may include multi-touch gestures and other gestures (e.g., swipes, finger pinches, taps, etc.). In gaming applications and other applications, it may be desirable to use a touch sensor on the rear surface of device  10  to gather touch input while displaying associated visual information on a display on the opposing front surface of device  10 . Configurations in which a user supplies touch input to the upper and lower ends of device  10  (e.g., in inactive areas IA) while holding device  10  in a landscape configuration to view images in active area AA of  FIG.  1    may also be used. Touch input on sidewalls in device  10  may be used as a control for a camera (e.g., a virtual shutter button input), may be used as input in other virtual button scenarios, may be used in implementing a volume slider button or a slider button for controlling other device operations (e.g., screen brightness, color settings, contrast settings, etc.). 
     A cross-sectional side view of an illustrative device with touch sensor and display structures is shown in  FIG.  3   . As shown in  FIG.  3   , device  10  may have walls such as opposing front wall  12 - 6  and rear wall  12 - 5  and walls such as left sidewall  12 - 4  and right sidewall  12 - 1 . Batteries, integrated circuits, and other electrical components  50  (see, e.g., control circuitry  30  and input-output devices  34 ) may be enclosed within the device enclosure formed from walls  12 . As shown in  FIG.  3   , components  50  may be mounted on one or more substrates such as substrate  48 . Substrates such as substrate  48  may include printed circuits (e.g., rigid printed circuit boards formed from rigid printed circuit board material such as fiberglass-filled epoxy and flexible printed circuits formed from flexible layers of polymer such as polyimide or other flexible sheets of polymer), molded plastic, glass, ceramic, and other dielectric substrate materials. 
     Portions of walls  12  of device  10  may be transparent. In the illustrative configuration of  FIG.  3   , for example, front wall  12 - 6  has been formed from a transparent material such as glass (i.e., wall  12 - 6  in the  FIG.  3    example may form a planar display cover layer). Display layer  46  (e.g., a liquid crystal display layer, an organic light-emitting diode display layer, or any other display layer for display  14 ) may form images (i.e., display layer  46  may contain an array of pixels to form display  14 ). Edge portions IA may have an inner surface coated with black masking layer BM, thereby rendering these portions of wall  12 - 6  opaque. Touch sensor circuitry  32  may be formed in active area AA and in inactive areas IA. This allows a user to supply touch input in areas IA (e.g., using the user&#39;s thumbs, other fingers such as finger  52  of  FIG.  3   , and/or other external objects) without blocking display layer  46 . Other portions of the enclosure of device  10  may be opaque. For example, the sidewalls of device  10  such as walls  12 - 4  and  12 - 1  and upper and lower walls  12 - 2  and  12 - 3  ( FIG.  1   ) may be formed form opaque material and rear wall  12 - 5  may be formed form opaque material. As shown in  FIG.  3   , touch sensor layer  32  may be formed on the inner surfaces of some or all of these opaque walls to provide the exterior surfaces of these portions of device  10  with touch input capabilities. 
     In the illustrative example of  FIG.  3   , the enclosure sidewalls for device  10  are flat and are oriented vertically. Cross-sectional side views of an edge portion of device  10  in scenarios in which device  10  has different illustrative sidewall profiles are shown in  FIGS.  4 ,  5 ,  6 , and  7   . In  FIG.  4   , sidewall  12 - 4  has a vertical shape and runs perpendicular to the planes of upper wall  12 - 6  and rear wall  12 - 5 . Upper wall  12 - 6  and rear wall  12 - 5  may be planar or may have convex and/or concave shapes. The example of  FIG.  5    shows how sidewall  12 - 4  may slope away from front wall  12 - 6 . The example of  FIG.  6    show how sidewall  12 - 4  may slope away from rear wall  12 - 5 . Another illustrative configuration is shown in  FIG.  7   . With the arrangement of  FIG.  7   , sidewall  12 - 4  has a curved shape. The profile of a curved wall in device  10  may be semicircular, may have one or more flat sections joined by one or more curved portions, may have a half-oval shape, or may have any other curved and/or straight wall profile. The arrangement of  FIG.  7    is shown as an example. Sidewall profiles of the types shown in  FIGS.  4 ,  5 ,  6 , and  7   , may be used on one, two, or three or more peripheral edges of device  10 . 
     An illustrative display layer for displays in device  10  such as display  14  is shown in  FIG.  8   . As shown in  FIG.  8   , display layer  46  may include an array of pixels  66  such as pixel array  44 . Pixel array  44  may be controlled using control signals produced by display driver circuitry. Display driver circuitry may be implemented using one or more integrated circuits (ICs) and/or thin-film transistors or other circuitry. The display driver circuitry may include, for example, display driver circuitry  60  that receives image data from control circuitry  30  via path  62  and gate driver circuitry  64 . The display driver circuitry may convert the image data into signals for controlling pixels  66  of pixel array  44 . 
     Pixel array  44  may contain rows and columns of pixels  66 . The circuitry of pixel array  44  (i.e., the rows and columns of pixel circuits for pixels  66 ) may be controlled using signals such as data line signals on data lines D and gate line signals on gate lines G. Data lines D and gate lines G are orthogonal. For example, data lines D may extend vertically and gate lines G may extend horizontally (i.e., perpendicular to data lines D). 
     Pixels  66  in pixel array  44  may contain thin-film transistor circuitry (e.g., polysilicon transistor circuitry, amorphous silicon transistor circuitry, semiconducting-oxide transistor circuitry such as indium gallium zinc oxide transistor circuitry, other silicon or semiconducting-oxide transistor circuitry, etc.) and associated structures for producing electric fields across a liquid crystal layer (in a liquid crystal display), for applying control signals to light-emitting diodes (in an organic light-emitting diode display or other display with pixels formed from light-emitting diodes), or for producing other pixel control signals (e.g., control signals for pixels in other types of displays). The thin-film transistor structures that are used in forming pixels  66  may be located on a thin-film transistor substrate such as a flexible polymer layer, a layer of glass, or other substrate(s)  68 . 
     Gate driver circuitry  64  may be used to generate gate signals on gate lines G. The gate driver circuitry may be formed from thin-film transistors on the thin-film transistor layer or may be implemented in separate integrated circuits. The data line signals on data lines D in pixel array  44  carry analog image data (e.g., voltages with magnitudes representing pixel brightness levels). During the process of displaying images on display layer  46 , a display driver integrated circuit or other circuitry  60  may receive digital data from control circuitry  30  via path  62  and may produce corresponding analog data signals. The analog data signals may be demultiplexed and provided to data lines D. If desired, other types of control schemes may be used for pixels  66  in array  44  of display layer  46 . The arrangement of  FIG.  8    is merely illustrative. 
       FIG.  9    is a diagram of an illustrative touch sensor for device  10 . Touch sensor layers for device  10  may be formed using any suitable touch technology. With the example of  FIG.  9   , touch sensor layer  32  is a capacitive touch sensor layer having capacitive touch sensor electrodes  70  and  72 . Touch sensor controller  74  may supply drive signals to the touch sensor electrodes while gathering corresponding sense signals from the electrodes, thereby determining the location of a user&#39;s touch within the electrodes. Electrodes  70  and  72  may be formed from a transparent conductive material such as indium tin oxide or invisibly thin conductive lines (e.g., in configurations in which it is desired for layer  32  to be transparent) or from opaque materials such as metal (e.g., in configurations in which layer  32  need not be transparent). Electrodes  70  and  72  may be formed on opposing sides of a flexible printed circuit, may be formed as multiple layers in a touch sensor coating formed on walls  12  or other portions of device  10 , may be formed using single-sided electrode patterns, may be formed using double-sided electrode patterns, may be formed on the same substrate as pixels  66  (e.g., in an arrangement in which some of the display structures and some of the touch sensor structures are shared and form a unitary touch and display layer), may be formed using patterns of squares, diamonds, or other capacitive electrode shapes, or may be formed using any other suitable touch sensor configuration. The configuration of  FIG.  9    in which sets of perpendicular touch sensor capacitive electrode strips are arranged in a grid is merely illustrative. 
       FIGS.  10 ,  11 ,  12 , and  13    are cross-sectional side views of a portion of enclosure wall  12  for device  10  that have been covered with display layers and/or touch sensor layers using different illustrative configurations. 
     In the arrangement of  FIG.  10   , wall  12  is opaque and touch sensor layer  32  has been attached to wall  12  using adhesive layer  80 . Layer  32  may be, for example, a flexible touch sensor panel formed on a flexible printed circuit substrate using metal capacitive touch sensor electrodes (e.g., wires, metal strips, metal pads, etc.). 
     In the arrangement of  FIG.  11   , wall  12  is opaque. Touch sensor layer  32  has been fabricated as a coating on the inner surface of wall  12  by depositing and patterning touch sensor structures. As an example, electrodes  70  may be deposited as a coating layer on the inner surface of wall  12  and patterned using photolithography, laser etching, etc. Shadow mask patterning may also be used, if desired. Dielectric layer  82  (e.g., a polymer or an inorganic dielectric layer) may then be deposited over electrodes  70 . Electrodes  72  may be deposited and patterned on dielectric layer  82  to form touch sensor layer  32 . 
     In portions of device  10  in which display output is desired, wall  12  may be transparent. An illustrative portion of wall  12  that is transparent is shown in  FIG.  12   . In the arrangement of  FIG.  12   , touch sensor layer  32  has been formed as a coating on the inner surface of transparent wall  12  (e.g., by depositing electrodes  70 , dielectric coating  82 , and electrodes  72 ). Display layer  46  (e.g., a display formed form a rigid substrate or a flexible polymer substrate) may be attached to the inner surface of transparent wall  12  over touch sensor layer  32  using a layer of clear adhesive such as adhesive  86 . If desired, a display layer may be deposited and patterned as a coating on touch sensor layer  32  and/or display layer structures and touch sensor structures may be formed as a unitary layer and deposited on wall  12  as a coating or attached to wall  12  with adhesive. 
     If desired, both the touch sensor layer and the display layer may be provided on flexible substrates or other suitable substrates that are attached to the inside of a transparent portion of wall  12  using adhesive layers. This type of arrangement is shown in  FIG.  13   . As shown in  FIG.  13   , adhesive layer  80  may be used to attach touch sensor layer  32  (e.g., a flexible printed circuit touch sensor formed from capacitive touch sensor electrodes on a flexible polymer substrate) to transparent wall  12  and adhesive layer  86  may be used to attach display layer  46  (e.g., a flexible display such as an organic light-emitting diode display, an electrophoretic display, or other suitable display with an array of pixels  66 ) to touch sensor layer  32 . Adhesive layers  80  and  86  may be transparent to allow pixels  66  to produce images that are visible from outside of device  10  through transparent wall  12 . 
     The configurations for incorporating touch and display layers into device  10  under opaque and transparent portions of wall  12  that are described in connection with  FIGS.  10 ,  11 ,  12 , and  13    are merely illustrative. Other types of display and touch layer configuration may be used, if desired (e.g., arrangements in which a single substrate is used to support both touch and display circuitry, etc.). Moreover, in some situations display layer  46  may overlap only a portion of touch sensor layer  32  (e.g., layer  32  may have portions that extend out from under display layer  46  and are therefore uncovered by display layer  46 ). Display layer  46  may also have potions that do not overlap any portion of touch sensor layer  32 . 
     In configurations for device  10  in which some of the walls of device  10  are curved, flexible touch and/or display layers may be provided with corresponding curved shapes (e.g., by bending flexible display and/or touch sensor layers, etc.). Consider, as an example, the arrangement of device  10  that is shown in  FIG.  14   . As shown in the example of  FIG.  14   , device  10  may have six enclosure walls: opposing left and right sidewalls  12 - 4  and  12 - 1 , opposing top and bottom sidewalls  12 - 3  and  12 - 2 , and opposing front and rear sidewalls  12 - 6  and  12 - 5 . Inactive areas IA may extend as strips around some or all of the top and bottom ends of enclosure  12 . Display  14  may be formed in an active area AA that extends over at least the center portion of front wall  12 - 6 . Display layer(s)  46  for display  14  may optionally cover some or all of walls  12 - 4  and  12 - 6  and/or may cover some or all of rear wall  12 - 5 . Touch sensor layer(s)  32  may cover front wall  12 - 6  in active area AA and optionally in inactive areas IA, may cover some or all of sidewalls  12 - 4  and  12 - 6 , may cover some or all of rear wall  12 - 5 , and may cover some or all of upper and lower sidewalls  12 - 2  and  12 - 3 . If desired, display layers  46  may also cover portions of device  10  such as upper and lower sidewalls  12 - 2 ,  12 - 3 , rear wall  12 - 5 , etc. 
     In the illustrative configuration of  FIG.  14   , display and/or touch layers may have curved shapes that match the curved profiles of curved sidewalls  12 - 4  and  12 - 1 .  FIGS.  15 ,  16 , and  17    are cross-sectional side views of a device such as device  10  of  FIG.  14    taken along line  400  and viewed in direction  402 . 
     Illustrative device  10  of  FIG.  15    has a downward facing planar touch sensor such as touch sensor layer  32 - 2  and has an upwards facing touch sensor layer with curved sidewall portions such as touch sensor layer  32 - 1 . Front wall  12 - 6  and sidewalls  12 - 4  and  12 - 1  may be transparent and may, if desired, be formed from an integral member (e.g., a unitary glass layer, etc.) with a planar center portion (forming wall  12 - 6 ) and curved edge portions (forming curved sidewalls  12 - 4  and  12 - 1 ). Display layer  46  may have a planar portion that extends under transparent front planar wall  12 - 6  and integral curved edge portions that extend under transparent curved sidewalls  12 - 4  and  12 - 1 . Touch sensor layer  32 - 1  is transparent to allow images from display layer  46  to be viewed through walls  12 - 1 ,  12 - 4 , and  12 - 6 . Touch sensor  32 - 2  may be overlapped by rear wall  12 - 5  and may gather touch input through rear wall  12 - 5 . Rear wall  12 - 5  may be opaque and touch sensor  32 - 2  may be transparent or opaque. Electrical components  404  may be housed in the interior cavity of device  10  that is enclosed by the enclosure walls. 
     Illustrative device  10  of  FIG.  16    has an upwards facing planar touch sensor such as touch sensor layer  32 - 1  and has a downwards facing touch sensor layer with curved sidewall portions such as touch sensor layer  32 - 2 . Rear wall  12 - 5  and sidewalls  12 - 4  and  12 - 1  may be opaque and may, if desired, be formed from an integral member with a planar center portion (forming wall  12 - 5 ) and curved edge portions (forming curved sidewalls  12 - 4  and  12 - 1 ). Touch sensor layer  32 - 2  may be transparent or opaque. Display layer  46  and touch sensor layer  32 - 1  lie under planar front wall  12 - 6 . Front wall  12 - 6  and touch sensor layer  32 - 1  may be transparent to allow display  46  to produce visible images. Electrical components  404  may be housed in the interior cavity of device  10  that is enclosed by the enclosure walls. 
     Illustrative device  10  of  FIG.  17    has an upper wall portion formed from upper left sidewall portion  12 - 4 - 1 , front wall  12 - 6 , and upper right sidewall portion  12 - 1 - 1 . The upper wall portion may be transparent and may overlap transparent touch sensor layer  32 - 1  and display layer  46 , each of which may have curved edges that conform to the curved edge shape of the upper wall portion. Device  10  may also have a lower wall portion formed from lower left sidewall portion  12 - 4 - 2 , rear wall  12 - 5 , and lower right sidewall portion  12 - 1 - 2 . The lower wall portion may be opaque and may overlap a transparent or opaque touch sensor layer such as touch sensor layer  32 - 1 . Electrical components  404  may be housed in the interior cavity of device  10  that is enclosed by the enclosure walls. 
     If desired, device  10  may have an enclosure that allows device  10  to be folded one or more times along one or more fold axes. In the example of  FIG.  18   , the enclosure of device  10  is flexible along fold axis (bend axis)  100 . This allows device  10  to be folded and unfolded like a book. As shown in  FIG.  18   , end  104 A of a first half of device  10  is located adjacent to sidewall  12 - 1 A (e.g., a curved sidewall) and end  104 B of a second half of device  10  is located adjacent to sidewall  12 - 1 B (e.g., a curved sidewall). Opposing curved sidewall  12 - 4  runs parallel to fold axis  100  and may be formed from a flexible material. In the folded (closed) configuration of  FIG.  18   , ends  104 A and  104 B are adjacent to each other. When it is desired to open device  10 , ends  104 A and  104 B may be moved away from each other in directions  102 , causing device  10  and flexible wall portion  12 - 4  to flex along bend axis  100 . 
     Display layer  46  for device  10  may be located on rear wall portions  12 - 5 A and  12 - 5 B and/or may be located on front wall portions  12 - 6 A and  12 - 6 B. Touch sensor layer  32  may likewise be located on rear wall portions  12 - 5 A and  12 - 5 B and/or may be located on front wall portions  12 - 6 A and  12 - 6 B. 
     Portions of touch sensor layer  32  and/or display layer  46  may cover some or all of the sidewalls of device  10 . For example, a continuous display may be formed from display layers on walls  12 - 6 A and  12 - 6 B by ensuring that display layer  46  lies under curved wall  12 - 4  (which lies between walls  12 - 6 A and  12 - 6 B when device  10  is in its unfolded state). When a device of this configuration is opened, walls portions  12 - 6 A,  12 - 4 , and  12 - 6 B form a unitary display for device  10 , as shown in  FIG.  19   . Sidewall portions  12 - 1 A and  12 - 1 B and, if desired, some or all of wall portions  12 - 5 B and  12 - 5 A may optionally also be covered with display layer  46  and/or touch layer  32 . Display layer  46  may extend along all of device  10  parallel to bend axis  100  or may be restricted to a central strip (shown as area AA) that lies between respective strips of inactive areas IA on the upper and lower edges of device  10 . Touch sensor layer  32  may extend under area AA and may, if desired, extend under some or all of areas IA. 
     A cross-sectional side view of device  10  of  FIG.  18    taken along line  412  of  FIG.  18    and viewed in direction  414  in an illustrative configuration in which touch sensor layers are provided on surfaces  12 - 5 A,  12 - 5 B,  12 - 6 A,  12 - 6 B,  12 - 4 ,  12 - 1 A, and  12 - 1 B is shown in  FIG.  20   . Support structures  410  may be formed form an elastomeric material and/or other bendable materials to allow device  10  to be opened and closed by bending the enclosure for device  10  along bend axis  100 . Transparent touch sensor layer  32 - 1  and display layer  46  are overlapped by transparent walls  12 - 1 A,  12 - 6 A,  12 - 4 ,  12 - 6 B, and  12 - 1 B. Touch sensor layer  32 - 2  (e.g., a transparent or opaque touch sensor layer) may be overlapped by walls  12 - 5 A and  12 - 5 B (which may be opaque). Electrical components  404  may be housed in the interior of device  10  that is enclosed by the enclosure walls (i.e., components  404  may be interposed between wall  12 - 6 A and  12 - 5 A and between wall  12 - 6 B and  12 - 5 B. The walls of device  10  of  FIG.  20    (e.g., wall portion  12 - 4  and optionally other walls) may be flexible to accommodate opening and closing of device  10 . 
     Illustrative equipment of the type that may be used in fabricating device  10  is shown in  FIG.  21   . The equipment of  FIG.  21    may be used in processing display layers  46 , touch sensor layers  32 , walls  12 , and other structures for device  10  (shown collectively as structures  208 ). 
     Molding equipment  200  may be used to mold transparent glass, transparent sapphire, transparent plastic, or other transparent materials (e.g., under heat and pressure). Equipment  200  may be used to form walls with integral curved edges and other structures  208 . 
     Equipment  202  may include physical vapor deposition equipment, equipment for applying conductive ink, equipment for depositing and patterning semiconductor thin films, equipment for depositing and patterning metal and dielectric layers, printing equipment, equipment for deposing materials by spraying, dipping, screen printing, pad printing, needle dispensing, or other coating techniques, photolithographic patterning equipment, laser and mechanical patterning equipment, and other equipment for depositing and patterning layers of material for structures such as touch sensor layers  32  and display layers  46  (e.g., structures  208 ). Equipment  202  may be used to apply hard coatings to opaque and/or transparent plastic layers (flexible and/or rigid plastic) or other layers. A hard coating may, for example, form an antiscratch layer. The hard coating may be formed from silicon nitride, metal nitride, titanium nitride, silicon oxide, metal oxide, diamond-like coating material, or other material with abrasion resistance). 
     Lamination equipment  204  may be used to press layers of material together for structures  208  under heat and pressure and may be used to attach layers of material together using adhesive. Roller-based lamination equipment may be used to attach layers of material to curved walls. 
     Equipment  206  may be used to assemble structures  208  to form device  10  (e.g., using computer-controlled positioners, machine vision equipment, etc.). 
       FIG.  22    shows how layers such as illustrative flexible layer  304  (e.g., display layer  46  and/or touch sensor layer  32 ) may be laminated to the inside of housing wall  12 . Roller  306  may be used to press layer  304  against the planar and curved inner surfaces  312  of wall  12  in directions such as direction  310 , thereby causing adhesive layer  302  to attach layer  304  to wall  12 . Wall  12  may have a planar portion and curved sidewall portions and may be supported by support structure  320  (e.g., a support structure that uses a vacuum to hold wall  12  in place during processing). 
     If desired, display layer  46  and/or touch sensor layer  32  may be deposited and patterned as coating layers on the inner surface of wall  12 , as shown in  FIG.  23    (in which deposition and patterning equipment  314  is depositing and patterning layer  316 ) and  FIG.  24    in which patterning of layer  316  is complete and patterned layer  316 ′ (e.g., a touch and/or display layer) is present on the planar and curved inner surfaces of wall  12 . 
     In the illustrative arrangement of  FIGS.  25  and  26   , touch sensor and/or display layer structures such as structures  316 ′ are deposited and patterned on the surface of wall  12  ( FIG.  25   ) before wall  12  is molded or otherwise formed into its final shape by bending the ends of wall  12 . Following bending of the ends of wall  12  in directions  350 , wall  12  may have curved sidewall portions as shown in  FIG.  26   . 
     As shown in  FIG.  27   , electronic device  10  may have two flexible portions  550  to allow device  10  to fold along two respective bend axes  100 A and  100 B (e.g., to allow device  10  to be placed in an open position, a closed position, and one or more intermediate positions). As shown in  FIG.  28   , electronic device  10  may have three or more flexible portions  550  that allow device  10  to fold along three or more respective bend axes  100 A,  100 B,  100 C . . . (e.g., to allow device  10  to be placed in an open position, a closed position, and one or more intermediate positions). In general, device  10  may have any suitable number of hinge regions that allow device  10  to flex. Some or all of the exposed external layers of display  14  in devices such as these may be provided with layers for displays  14  and/or touch sensors  32  (e.g., a device with opposing front and rear surfaces covered with display and/or touch layers may have no hinges, one hinge, two hinges, three hinges, four or more hinges, etc.). 
     The flexible regions in device  10  may be provided with hinges based on flexible layers of material (e.g., flexible plastic, flexible metal, etc.), accordion (bellows) structures, pivoting hinge structures, and/or other suitable flexible structures. 
     In the illustrative configuration of  FIG.  29   , hinge  500  has been formed from flexible layer  502  (e.g., a flexible core layer of an elastomeric material, a flexible foam, a flexible polymer layer, a flexible metal layer, and/or other flexible layers) that has been covered with one or more layers of material  504  for forming displays  14  and/or touch sensors  32 . Layers  504  may be formed one or both sides of device  10 . Hinges such as hinge  500  may allow device  10  to bend around bend axis  100 . 
       FIG.  30    shows how hinge  600  may be formed from flexible accordion (bellows) structures  602 . One or more flexible layers  604  for displays  14  and/or touch sensors  32  may be formed on the upper and/or lower surfaces of hinge  600 . Accordion structures  602  may be formed from metal, plastic, or other materials that are sufficiently thin and flexible to allow the accordion structure to bend. Hinges such as hinge  600  may allow device  10  to bend around bend axis  100 . 
     In the example of  FIG.  31   , hinge  700  has been formed from a first structural member (member  702 ) that is coupled to a second structural member (member  704 ) by a pivot structure such as a pin and mating opening into which the pin protrudes. This allows hinge  700  to flex about bend axis  100 . 
     Other structures that flex with respect to each other may be used to form hinges for device  10 . The examples of  FIGS.  29 ,  30 , and  31    are merely illustrative. 
     To help prevent display and touch sensor structures in the flexible layers of device  10  from cracking or otherwise developing faults due to stresses induced by bending device  10 , these structures may be provided with stress tolerant features such as locally thinned substrate layers, serpentine metal traces that resist cracking when bent, neutral stress plane adjustments layers such as layers of polymer that can be applied as coatings in bending regions to help move the neutral stress plane of bent material into alignment with metal traces in the bending regions and thereby reduce bend-induced stresses and faults, redundant lines (e.g., stacked metal layers coupled by vias, side-by-side redundant lines, etc.), conductive paths formed from carbon nanotubes, metal paint, and/or other materials that resist cracking when bent, and/or other structures that help the flexible layers of device  10  resist damage during bending. 
     The foregoing is merely illustrative and various modifications can be made by those skilled in the art without departing from the scope and spirit of the described embodiments. The foregoing embodiments may be implemented individually or in any combination.