Patent Publication Number: US-2023156939-A1

Title: Electronic Devices Having Sliding Expandable Displays

Description:
This application is a continuation of patent application Ser. No. 17/349,050, filed Jun. 16, 2021, which is a continuation of patent application Ser. No. 16/744,564, filed Jan. 16, 2020, now U.S. Pat. No. 11,071,218, which claims the benefit of provisional patent application No. 62/832,217, filed Apr. 10, 2019, which are hereby incorporated by reference herein in their entireties. 
    
    
     FIELD 
     This relates generally to electronic devices, and, more particularly, to electronic devices with displays. 
     BACKGROUND 
     Electronic devices often include displays. A touch screen display may be used in a cellular telephone or other portable device to display information for a user and to gather user input. 
     If care is not taken, a display may not offer sufficient screen real estate to display information of interest to a user. At the same time, it can be difficult to enlarge the size of electronic devices too much to accommodate larger displays, because this can make devices too bulky. 
     SUMMARY 
     An electronic device may have a display mounted in a housing. The housing may have portions that slide relative to each other. When it is desired to place the device in a compact unexpanded state, the housing portions may be slid towards each other. When it is desired to expand the viewable size of the display, the housing portions may be slid away from each other. 
     The display in the device may be a flexible display such as an organic light-emitting diode display. The display may be doubled back on itself once or twice when it is desired to store a portion of the display. A tensioner may be used to provide the display with tension and thereby maintain the display in a desired shape such as a desired planar shape. 
     The housing portions that slide relative to each other may have interdigitated fingers or other slidably engaged housing structures. The display may be supported on a surface of the housing such as on a front face of the housing. The housing and display may be adjusted by a user. For example, the housing portions may slide between an unexpanded state in which the display has an unexpanded viewable area on the front face and an expanded state in which the display has an expanded viewable area on the front face that is greater than the unexpanded viewable area. 
     The electronic device housing may have an interior that contains electrical components. A doubled-back portion of a flexible display may be stored in an interior of the housing when the housing is in the unexpanded state. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is 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 illustrative electronic device in accordance with an embodiment. 
         FIG.  4    is side view of an illustrative electronic device with a foldable display in accordance with an embodiment. 
         FIG.  5    is a side view of an illustrative electronic device with a sliding display in accordance with an embodiment. 
         FIG.  6    is a side view of an illustrative electronic device with a scrolling display in accordance with an embodiment. 
         FIG.  7    is a cross-sectional side view of an illustrative flexible display structure in accordance with an embodiment. 
         FIG.  8    is a cross-sectional side view of an illustrative electronic device with a sliding display in an unexpanded position in accordance with an embodiment. 
         FIG.  9    is a cross-sectional side view of the illustrative electronic device of  FIG.  8    with the sliding display in an expanded position in accordance with an embodiment. 
         FIGS.  10 ,  11 , and  12    are side views of illustrative flexible display storage configurations with one or more display bends for use in electronic devices with sliding displays in accordance with an embodiment. 
         FIG.  13    is a top view of an illustrative flexible display tensioner such as a coil spring in accordance with an embodiment. 
         FIG.  14    is a cross-sectional side view of an illustrative electronic device with a sliding display in accordance with an embodiment. 
         FIGS.  15  and  16    are perspective views of the illustrative electronic device of  FIG.  14    in unexpanded and expanded configurations in accordance with an embodiment. 
         FIG.  17    is a cross-sectional side view of an illustrative electronic device with a sliding display in accordance with an embodiment. 
         FIGS.  18  and  19    are top views of an illustrative expandable electronic device housing structure with sliding interdigitated members in respective unexpanded and expanded configurations in accordance with an embodiment. 
         FIGS.  20 ,  21 ,  22 , and  23    are perspective views of illustrative expandable electronic device housing structures with sliding interdigitated members in accordance with embodiments. 
         FIG.  24    is a top view of an illustrative expandable electronic device housing structure with supporting side members in accordance with an embodiment. 
         FIGS.  25 ,  26 ,  27 , and  28    are cross-sectional views of illustrative sliding structures for expandable electronic device housings in accordance with embodiments. 
         FIG.  29    is a top view of an illustrative expandable electronic device housing structure showing illustrative locations for electrical components in accordance with an embodiment. 
         FIG.  30    is a perspective view of an illustrative expandable electronic device housing structure with flexible sliding interdigitated members in accordance with an embodiment. 
         FIG.  31    is a cross-sectional side view of the illustrative expandable electronic device housing structure of  FIG.  30    showing how a flexible display may wrap around an edge of the housing structure and may be supported by the flexible sliding interdigitated members in accordance with an embodiment. 
         FIG.  32    is a cross-sectional end view of an illustrative sliding device in accordance with an embodiment. 
         FIGS.  33  and  34    are top views of the illustrative sliding device of  FIG.  32    in unexpanded and expanded states in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     An electronic device may have a display. The display may have an array of pixels for displaying images for a user. The display may be an organic light-emitting diode display, a micro-light-emitting diode display formed from an array of crystalline semiconductor light-emitting diode dies, and/or may be any other suitable display. A two-dimensional touch sensor such as a capacitive touch sensor or other touch sensor may be incorporated into the display (e.g., by forming capacitive sensor electrodes from thin-film display circuitry) and/or a touch sensor layer may be laminated to an array of pixels in the display. 
     The display of the electronic device may be operated in unexpanded and expanded configurations. In the unexpanded configuration, portability of the device is enhanced. In the expanded configuration, viewable display area is increased, making it easier to provide touch input and to view images on the display. 
     A perspective view of an illustrative electronic device of the type that may include an expandable display is shown in  FIG.  1   . Device  10  may be a laptop computer, a computer monitor containing an embedded computer, a tablet computer, a desktop computer, a cellular telephone, a media player, or other handheld or portable electronic device, a smaller device such as a wristwatch device, a wristband device, a pendant device, a headphone or earpiece device, a head-mounted device such as glasses, goggles, a helmet, 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 equipment is mounted in a kiosk, in an automobile, airplane, or other vehicle, a removable external case for electronic equipment, an accessory such as a remote control, computer mouse, track pad, wireless or wired keyboard, or other accessory, and/or equipment that implements the functionality of two or more of these devices. In the illustrative configuration of  FIG.  1   , device  10  is a portable electronic device such as a cellular telephone or tablet. This configuration may sometimes be described herein as an example. 
     As shown in  FIG.  1   , device  10  may have a housing such as housing  12 . Housing  12  may be formed from materials such as polymer, glass, metal, crystalline materials such as sapphire, ceramic, fabric, foam, wood, other materials, and/or combinations of these materials. Device  10  may have any suitable shape. In the example of  FIG.  1   , device  10  has front face F, opposing rear face R, and sidewall portions (sidewalls) W. Portions W may be formed as extensions of the housing structures on front face F, rear face R, and/or may be formed using one or more separate sidewall members (as examples). Sidewall structures may be planar (e.g., to form vertical sidewalls extending between front F and rear R) and/or may have curved cross-sectional profiles. Input-output devices such as one or more buttons may be mounted on housing  12  (e.g., on sidewall portions W). 
     Device  10  may have one or more displays such as display  14 . In the example of  FIG.  1   , display  14  covers front face F. Display  14  may also be mounted on other portions of device  10 . For example, one or more displays such as display  14  may cover all of front face F, part of front face F, some or all of rear face R, and/or some or all of sidewalls W. In some configurations, some or all of display  14  may be covered with flexible or rigid transparent members that serve as protective display cover layers. Such transparent display cover layer structures, which may sometimes be referred to as housing structures, may overlap at least some of display  14  and may serve as a display cover layer. If desired, transparent thin-film structures may serve as protective display layers (e.g., scratch-resistance layers, oleophobic anti-smudge coating layers, etc.). 
     Display  14  may have a planar shape, a shape with a curved cross-sectional profile, or other suitable shape. In the example of  FIG.  1   , front face F has a planar shape and lies in the X-Y plane. Display  14  may have a rectangular footprint (outline when viewed from above) or other suitable footprint. Device  10  is elongated along longitudinal axis  56  (e.g., parallel to the Y axis of  FIG.  1   ). The thickness of device  10  in dimension Z, may be less than the width of device  10  in dimension X and less than the length of device  10  in dimension Y (as an example). 
     To help accommodate a user&#39;s desire for compactness while accommodating a user&#39;s desire for large amounts of display real estate, device  10  can have structures that allow the shape and size of device  10  and display  14  to be adjusted. In particular, device  10  may have a display and associated housing structures that support folding motions, sliding motions, scrolling motions, and/or other behavior that allows device  10  to be adjusted during use. 
     When compact size is desired, device  10  can be adjusted to be compact. Device  10  and display  14  may, as an example, be folded inwardly or outwardly about bend axis  58 . As another example, sliding or scrolling display structures can be retracted so that device size is minimized. 
     When a large screen size is desired, device  10  and display  14  can be unfolded (in a configuration in which device  10  is foldable) or display  14  can be expanded laterally in one or more directions such as direction  52  (parallel to longitudinal axis  56 ) or direction  54  (e.g., a lateral direction that is perpendicular to longitudinal axis  56  and perpendicular to the thickness of device  10 ). Device  10  and display  14  may, for example, be expanded by sliding portions of device  10  (and display  14 ) along axis  56  or axis  58  or by unscrolling a scrolled flexible display in direction  52  or direction  54 . 
     When expanded, display  14  exhibits an expanded viewable area. In particular, the portion of display  14  that is viewable by a user of device  10  when device  10  is expanded (sometimes referred to as the expanded viewable area of display  14 ) is larger than the unexpanded viewable area of display  14  that is presented to a user of device  10  when device  10  is unexpanded. In general, device  10  may use any suitable arrangement that allows display and/or device size and/or shape to be adjusted (e.g., between a first configuration such as an unexpanded viewable area configuration in which a first amount of display  14  is visible to a user viewing the front face of device  10  or other side of device  10  and a second configuration such as an expanded viewable area configuration in which a second amount of display  14  that is greater than the first amount is visible to a user viewing the front face of device  10  or other side of device  10 ). These arrangements may exhibit inward and/or outward folding, scrolling, sliding, and/or other housing and display movements as device  10  and display  14  are transitioned between unexpanded and expanded states. 
     A schematic diagram of an illustrative electronic device is shown in  FIG.  2   . As shown in  FIG.  2   , device  10  may include control circuitry  30 , communications circuitry  32 , and input-output devices  34 . 
     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 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 gather input from sensors and other input devices and may be used to control output devices. The processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, baseband processors and other wireless communications circuits, power management units, audio chips, application specific integrated circuits, etc. 
     To support communications between device  10  and external electronic equipment, control circuitry  30  may communicate using communications circuitry  32 . Communications circuitry  32  may include antennas, radio-frequency transceiver circuitry, and other wireless communications circuitry and/or wired communications circuitry. Circuitry  32 , which may sometimes be referred to as control circuitry and/or control and communications circuitry, may, for example, support wireless communications using wireless local area network links, near-field communications links, cellular telephone links, millimeter wave links, and/or other wireless communications paths. 
     Input-output devices  34  may be used in gathering user input, in gathering information on the environment surrounding the user, and/or in providing a user with output. 
     Display  14  of input-output devices  34  has an array of pixels for displaying images to users. Display  14  may be a light-emitting diode display (e.g., an organic light-emitting diode or a display with a pixel array having light-emitting diodes formed from crystalline semiconductor dies), an electrophoretic display, a liquid crystal display, or other display. Display  14  may include a two-dimensional capacitive touch sensor or other touch sensor for gathering touch input. Display  14  may have a substrate formed from a flexible dielectric (e.g., a sheet of polyimide or other bendable polymer layer) and/or may have rigid substrate structures. Flexible display arrangements may be used to provide display  14  with the ability to alter size and shape by folding, scrolling, sliding, etc. If desired, some or all of display  14  may include rigid (non-flexible) display structures. 
     Devices  34  may include sensors  36 . Sensors  36  may include force sensors (e.g., strain gauges, capacitive force sensors, resistive force sensors, etc.), audio sensors such as microphones, capacitive touch sensors, capacitive proximity sensors, non-capacitive touch sensors, ultrasonic sensors, sensors for detecting position, orientation, and/or motion (e.g., accelerometers, magnetic sensors such as compass sensors, gyroscopes, and/or inertial measurement units that contain some or all of these sensors), muscle activity sensors (EMG), heart rate sensors, electrocardiogram sensors, and other biometric sensors, radio-frequency sensors (e.g., radar and other ranging and positioning sensors), humidity sensors, moisture sensors, and/or other sensors. 
     Sensors  36  and other input-output devices  34  may include optical components such as light-emitting diodes (e.g., for camera flash or other blanket illumination, etc.), lasers such as vertical cavity surface emitting lasers and other laser diodes, laser components that emit multiple parallel laser beams (e.g., for three-dimensional sensing), lamps, and light sensing components such as photodetectors and digital image sensors. For example, sensors  36  in devices  34  may include optical sensors such as depth sensors (e.g., structured light sensors and/or depth sensors based on stereo imaging devices that can optically sense three-dimensional shapes), optical sensors such as self-mixing sensors and light detection and ranging (lidar) sensors that gather time-of-flight measurements and/or other measurements to determine distance between the sensor and an external object and/or that can determine relative velocity, monochromatic and/or color ambient light sensors that can measure ambient light levels, proximity sensors based on light (e.g., optical proximity sensors that include light sources such as infrared light-emitting diodes and/or lasers and corresponding light detectors such as infrared photodetectors that can detect when external objects are within a predetermined distance), optical sensors such as visual odometry sensors that gather position and/or orientation information using images gathered with digital image sensors in cameras, gaze tracking sensors, visible light and/or infrared cameras having digital image sensors configured to gather image data, optical sensors for measuring ultraviolet light, and/or other optical sensor components (e.g., light sensitive devices and, if desired, light sources), photodetectors coupled to light guides, associated light emitters, and/or other optical components (one or more light-emitting devices, one or more light-detecting devices, etc.). 
     Input-output devices  34  may also include audio components. The audio components may include one or more microphones to sense sound (e.g., an audio sensor in sensors  36  to sense audio signals) and may include sound-emitting components such as tone generators and one or more speakers. As shown in  FIG.  2   , for example, input-output devices  34  may include speaker  38 . Speakers may be used to support speaker-phone operations and/or may be used as ear speakers when device  10  is being held to a user&#39;s ear to make a telephone call, to listen to a voicemail message, or to listen to other audio output. 
     In addition to sensors  36 , display  14 , and speaker  38 , input-output devices  34  may include user input devices such as buttons and other devices  40 . Devices  40  may include, for example, optical components such as light-based output devices other than display  14  that are used to provide visual output to a user. The light-based output devices may include one or more light-emitting diodes, one or more lasers, lamps, electroluminescent devices, and/or other light emitting components. The light-based output devices may form status indicator lights. If desired, the light-based output devices may include illuminated icons (e.g., backlight symbols associated with power indicators, battery charge indicators, wireless signal strength indicators, notification icons, etc.). 
     Devices  40  may include electromagnets, permanent magnets, structures formed from magnetic material (e.g., iron bars or other ferromagnetic members that are attracted to magnets such as electromagnets and/or permanent magnets), batteries, etc. Devices  40  may also include power transmitting and/or receiving circuits configured to transmit and/or receive wired and/or wireless power signals and output components such as haptic output devices and other output components (e.g., electromagnetic actuators or other actuators that can vibrate to provide a user with a haptic alert and/or haptic feedback associated with operation of a touch sensor or other input devices). 
     A cross-sectional side view of device  10  of  FIG.  1    is shown in  FIG.  3   . As shown in  FIG.  3   , housing  12  may have one or more portions such as sidewall portions  12 W, front portion  12 F on front face F of device  10 , and rear portion  12 R on rear face R of device  10 . These portions may be formed from metal (e.g., aluminum, stainless steel, or other metals) or may be formed from polymer, glass, ceramic, and/or other materials. 
     Display  14  may be visible on front face F of device  10  and/or other portions of device  10 . For example, a viewer who is viewing device  10  in the −Z direction of  FIG.  3    (e.g., a user viewing device  10  from the front) may view the pixels of display  14  on front face F that face the user in the +Z direction). Display  14  may be overlapped by transparent portions of housing  12 , may have portions that are supported on the outermost surface of housing  12 , and/or may have portions that protrude from housing  12 . In some configurations, rigid protective transparent materials may form a display cover layer that protects display  14 . Display  14  may also be protected by attaching protective thin films to the outermost surface of display  14  and/or by incorporating protective thin films into display  14 . As an example, a clear polymer film may overlap the pixels of display  14  to help protect the circuitry of the pixels from damage and/or thin-film organic and/or inorganic layers may be incorporated into display  14  to help protect display  14 . In some arrangements, display  14  may include flexible protective material (e.g., a bendable polymer thin film, bendable inorganic thin-film layers, etc.). Transparent materials that may overlap display  14  (e.g., to protect display  14 ) may be formed from sapphire or other crystalline material, glass, polymer, transparent ceramic, inorganic dielectric materials such as transparent metal oxide thin films and/or other inorganic materials, and/or other transparent material and/or other flexible and/or rigid transparent materials. 
     The walls of housing  12  may separate interior region  44  of device  10  from exterior region  50  surrounding device  10 . Interior region  44  may include components such as components  46 . Components  46  may include integrated circuits, discrete components, a battery, wireless circuit components such as a wireless power coil, and/or other components (see, e.g., control circuitry  30 , communications circuitry  32 , and input-output devices  34  of  FIG.  2   ). Components  46  may be interconnected using signal paths such as paths formed from traces on printed circuits (see, e.g., printed circuit  48 ). 
     To accommodate the sometimes competing desires for compact device size and large screen size, device  10  can be adjusted between a first state in which display  14  is unexpanded and a second state in which display  14  is expanded and therefore larger than when unexpanded. 
     With one illustrative arrangement, device  10  accommodates display bending. Display  14  may, for example, be folded inwardly so that left and right halves of display  14  face each other (e.g., when display  14  is formed on surface  62  of housing  12  of  FIG.  4   ). Display  14  may also be folded outwardly so that left and right halves of display  14  face away from each other (e.g., when display  14  is formed on surface  60  of housing  12  of  FIG.  4   ). If desired, device  10  may support both inward and outward folding. 
     Arrangements in which device  10  allows display  14  to be changed in size using sliding motions may also be used. As shown in  FIG.  5   , for example, device  10  may be adjusted so that structures in device  10  and display  14  slide (in direction  52  or other suitable direction) between a first (unexpanded) configuration in which only display area  14 ′ is visible and a second (expanded) configuration in which both display area  14 ′ and display area  14 ″ are visible. 
       FIG.  6    is a side view of device  10  in an illustrative configuration in which display  14  is sufficiently flexible to be scrolled. This allows display  14  to move in and out of housing  12 . In an unexpanded configuration, display  14  is rolled up and stored in housing  12  of  FIG.  6   . In an expanded configuration, display  14  is enlarged by unscrolling display  14  in direction  52  and causing display  14  to extend out of housing  12 . Other arrangements that allow display  14  to be changed in size and/or shape may also be used and/or combinations of these arrangements and/or the arrangements of  FIGS.  4 ,  5 , and  6    may be used. 
     If desired, display  14  may have an array of light-emitting pixels P. This type of arrangement is shown in  FIG.  7   . In the example of  FIG.  7   , display  14  includes substrate  71 A, pixel array  71 B, and covering layer  71 C. Substrate  71 A may be formed from a sheet of polyimide, other flexible polymer layer, or other dielectric. Substrate  71 A may be covered by thin-film layers forming pixels P and other thin-film circuitry. Pixels P may include thin-film transistors  78 , thin-film capacitors, thin-film light-emitting diodes  76  such as organic light-emitting diodes, and/or other thin-film circuitry. If desired, an array of pixels P for display  14  may be formed from micro-light-emitting diodes (sometimes referred to as microLEDs) formed from crystalline semiconductor dies. These dies may be mounted on a flexible substrate. One or more encapsulation layers such a layer  71 C may be used to protect and environmentally seal pixels P. Layer(s)  71 C may include organic and/or inorganic dielectric layers (e.g., thin-film layers). Additional layers such as one or more support layers on the rear of display  14  (see, e.g., backing layer  70 ) and/or one or more outwardly facing layers on the outwardly facing side of display  14  (see, e.g., layer  72 ) may be attached to display  14 , if desired (e.g., using layers of adhesive, by forming thin-film layers directly on display  14  and/or by incorporating other layers overlapped by the pixels P into display  14 ). Backing layers such a layer  70  may be formed from metal (e.g., thin flexible metal that can withstand repeated bending and unbending), may be formed from polymer, may be formed from other materials, and/or may be formed from combinations of these materials. During bending, layers such as layer  70  may help protect display  14  from wrinkling or other potentially damaging deformation. Additional layer(s)  72  may include polarizer layers, wave plates, filters, protective cover layers, privacy films, and/or other display layers. 
       FIG.  8    is a cross-sectional side view of an illustrative electronic device with a display that is expandable using a sliding motion. Housing  12  of device  10  of  FIG.  8    has portions such as first portion  12 - 1  and second portion  12 - 2 . Portions  12 - 1  and  12 - 2  may slide towards and away from each other. In the arrangement of  FIG.  8   , portions  12 - 1  and  12 - 2  have been placed adjacent to each other so that device  10  and display  14  are in an unexpanded state. Display  14  is a flexible display and may be deployed from interior  44  to exterior  50  through opening  86  (e.g., a slot) in housing  12  using roller  80  or other suitable deployment mechanism. Roller  80  may be coupled to housing  12  by an axle (as an example) and may rotate relative to housing  12 . In the unexpanded state of  FIG.  8   , display has a first portion  14 - 1  that is viewable from exterior  50  of device  10  and has a second portion  14 - 2  that is housed within interior  44  and is not viewable from exterior  50 . Display  14  may, for example, have one or more bends (folds) that allow display  14  to double back on itself so that portion  14 - 2  may be stored in interior  44 . Housing portions  12 - 1  and  12 - 2  (e.g., the upper surfaces of these structures) may be used to help support display  14  and maintain display  14  in a desired shape such as a planar shape. A stretchable elastomeric member, spring, or other tensioner such as tensioner  82  may be coupled between a portion of housing portion  12 - 1  (see, e.g., attachment structure  84 ) and an end of display portion  14 - 2  to help tension display  14  and thereby maintain display  14  in a desired shape (e.g., a planar shape on the surface of housing  12 ). 
     When it is desired to extend the area of display  14 , housing portion  12 - 2  may be moved away (e.g., slid away) from housing portion  12 - 1  in direction  52 , as shown in  FIG.  9   . Supporting portions  12 - 3  of housing  12  (e.g., rails or other structures associated with housing portion  12 - 1 , associated with housing portion  12 - 2 , and/or other portions of housing  12 ) may be used to help maintain portion  12 - 2  in a desired orientation relative to portion  12 - 1  (e.g., supporting portions  12 - 3  may be used to maintain angular alignment between portions  12 - 1  and  12 - 2 ). By sliding housing portions  12 - 1  and  12 - 2  apart, display  14  may be placed in its expanded state. As shown in  FIG.  9   , portion  14 - 2  of display  14  may be removed from interior  44  through opening  86  during expansion, so that the visible area of display  14  in an expanded viewing area configuration includes both portion  14 - 1  and portion  14 - 2 . Tensioner  82  (e.g., a spring) may expand (e.g., by stretching, etc.) to accommodate movement of portion  14 - 2  out of interior  44  while providing tension to help flatten display  14  on the outer surface of housing  12 . 
       FIGS.  10 ,  11 , and  12    are cross-sectional side views of display  14  showing shapes in which display  14  (e.g., display portion  14 - 2 ) may be stored (e.g., in interior  44 ). Display  14  may be placed in these unexpanded configurations when it is desired to reduce the size of device  10 . In the example, of  FIG.  10   , display  14  has been doubled back on itself using a single bend. This doubled-back display configuration, which is used in the example of  FIGS.  8  and  9   , allows one half of display  14  to be viewed when display  14  is unexpanded and allows both halves of display  14  to be viewed when display  14  is expanded. In the example of  FIG.  11   , display has two bends and is doubled back on itself twice when placed in its unexpanded (folded) configuration. A third of display  14  or other suitable portion of display  14  may be viewable when display  14  is unexpanded in this arrangement. When fully expanded, the folded back portions of display  14  of  FIG.  11    may be drawn out of the interior of housing  12  through opening  86  and thereby expanded for viewing by a user. A pair of rollers such as roller  80  of  FIG.  8    may be used to retract and deploy display  14  in two-bend (twice doubled-back) storage arrangements. Another illustrative storage configuration for display  14  is shown in  FIG.  12   . In the example of  FIG.  12   , display  14  is also bent back twice (as with the arrangement of  FIG.  11   ), but both bends are inward bends (inward folds), whereas in the arrangement of  FIG.  11   , display  14  is first bent inwardly and is then bent in the opposite direction. A pair of rollers at opposing ends of the interior portion of a device housing structure may be used to help store and deploy display  14  in arrangements of the type shown in  FIG.  12   . Tensioners may be used (e.g., by coupling springs or other tensioners  82  to the interior ends of display  14  of  FIG.  11    and/or  FIG.  12   ) to help tension display  14  when display  14  is in the unexpanded and expanded states. 
     The examples of  FIGS.  10 ,  11 , and  12    are illustrative. If desired, display  14  may be stored using other arrangements. For example, display  14  may be wrapped multiple times around a single roller, may slide into in interior portion of housing  12  without bending, and/or may otherwise be stowed when it is desired to place display  14  in its unexpanded state. When display  14  is doubled back on itself so that display  14  has one or two bends and associated doubled-back planar sections, display  14  may avoid some of the stress that might otherwise be experienced by wrapping display  14  repeatedly about a roller. 
     Tensioner  82  may be a flat spring, a clock spring, a leaf spring, an extension spring, a compression spring, a coil spring, a stretchable elastomeric member, and/or other suitable tensioning device. A top view of an illustrative tensioner formed from a coil spring is shown in  FIG.  13   . As shown in  FIG.  13   , the coil spring forming tensioner  82 , which may sometimes be referred to as a torsion spring, may have a helical spring member such as member  89  attached to an interior support in device  10  such as support  84  at attachment point  92 . Helical spring member  89 , which may be formed from a material such as spring metal, may have an opposing end that is attached to roller  90  at point  104 . Roller  90  may have an axle coupled to housing  12  and may rotate about rotational axis  106 . Coupling member  108  (e.g., a flexible band) may wrap around roller  90  and may be attached to the edge of flexible display  14 . When spring  82  is relaxed, coupling member  108  will be retracted towards spring  82  and wrapped around roller  90 . In this state, display portion  14 - 2  will be retracted into housing interior  44 , as shown in  FIG.  8   . When display  14  is pulled out of interior  44  in response to sliding apart housing portions  12 - 1  and  12 - 2 , coupling member  108  will unwrap from roller  90  while tightening helical spring member  89 . Other types of tensioning mechanisms may be used to tension the edges of display  14 , if desired. The coil spring example of  FIG.  13    is illustrative. 
     Housing portions  12 - 1  and  12 - 2  may be the same size, housing portion  12 - 1  may be larger than housing portion  12 - 2 , or housing portion  12 - 2  may be larger than housing portion  12 - 1 . Housing portions  12 - 1  and  12 - 2  may have the same shape (or nearly the same shape) or may have different shapes that engage with each other. In the illustrative example of  FIG.  14   , housing portion  12 - 2  has a thin protruding portion  12 - 2 P (formed from one or more strip-shaped members) that extends over a box-shaped structure forming main housing portion  12 - 1 . Electrical components may be mounted in the interior of portion  12 - 1  and/or portion  12 - 2 . For example, a battery, control circuitry, and other components may be mounted in the interior of main housing portion  12 - 1  in the example of  FIG.  14   . 
     As described in connection with  FIGS.  8  and  9   , display  14  of  FIG.  14    may be a flexible display that extends around internal roller  80  during storage of display  14  in housing  12  when display  14  is in its unexpanded state. When display  14  is in its unexpanded state, a first portion of display  14  is visible, as shown in  FIG.  15   . When portion  12 - 2  is slid away from portion  12 - 1 , protruding portion  12 - 2 P slides off of the upper surface of portion  12 - 1  and display  14  is drawn out of the interior of portion  12 - 1  through opening  86 . The places display  14  in its expanded state, as shown in  FIG.  16   . 
     If desired, a protruding structure in one portion of housing  12  may be received within a recess of another portion of housing  12 . Consider, as an example, the arrangement of  FIG.  17   . In the example of  FIG.  17   , housing portion  12 - 1  has a recess formed between lower structure  12 - 1 P′ and upper structure  12 - 1 P. When display  14  is in its unexpanded configuration, protruding structure  12 - 2 P of housing portion  12 - 2  protrudes into and is received within the recess in structure  12 - 1 . Because upper structure  12 - 2 P may remain in place even when protruding structure  12 - 2 P has been withdrawn from the recess, the presence of upper structure  12 - 1 P may help support display  14  on the outer surface of device  10  when display  14  is expanded. Structures of the type show in  FIG.  17    may be formed across the entire width of device  10  and/or interdigitated structures may be formed. The interdigitated protrusions of housing  12  may sometimes be referred to as interlocking (interdigitated) rails, protrusions, strip-shaped protrusions, strip-shaped members, fingers, prongs, etc. 
     Device  10  may, in general, use trailing edge or leading edge configurations for deploying display  14 . In the arrangement of  FIG.  17   , for example, the roller and supplemental storage area used for deploying additional portions of display  14  are located in housing  12 - 1 , which is sometimes referred to as the trailing side of housing  12 , because housing  12 - 2  is pulled out of housing  12 - 1  and extends outwardly in a leading fashion away from housing  12 - 1 . If desired, roller  80  may be located in housing  12 - 2  and/or portions of display  14  may be stored within housing  12 - 2  when device  10  is in its unexpanded configuration. 
     A top view (front face view) of an illustrative pair of interlocking housing structures with interdigitated members (e.g., interdigitated members that extend across front face F) is shown in  FIG.  18   . As shown in  FIG.  18   , device  10  may have interlocking housing portions  12 - 1  and  12 - 2  that are configured to allow housing portions  12 - 1  and  12 - 2  to slide towards and away from each other. This may allow the size of display  14  to be adjusted. For example, display  14  may be a flexible display having a first portion stored inside housing portion  12 - 1  when display  14  is in its unexpanded state and a second portion attached to housing portion  12 - 2 . When housing portion  12 - 2  is moved away from housing portion  12 - 1 , display  14  may be pulled out of housing portion  12 - 1  to increase the viewable size of display  14 . 
     Housing portion  12 - 1  of  FIG.  18    has a series of elongated members (sometimes referred to as fingers) such as members  12 M 1  and housing portion  12 - 2  may have a series of interlocking offset elongated members (fingers) such as members  12 M 2 . The recesses formed between adjacent members on one portion (e.g., the elongated recesses between respective pairs of adjacent members  12 M 1 ) are configured to receive the elongated members of the other portion (e.g., members  12 M 2 ) and vice versa. The interlocking structures of  FIG.  18    (e.g., the members of portion  12 - 1  and the corresponding members of portion  12 - 1 ) are configured to slidably engage so that housing portion  12 - 1  and  12 - 2  slide with respect to each other while serving as a robust support for display  14 . The illustrative housing of  FIG.  18    is shown in an expanded configuration (following sliding movement to move portions  12 - 1  and  12 - 2  away from each other) in  FIG.  19   . 
     The sizes of members  12 M 1  and  12 M 2  may be equal or members  12 M 1  may be larger or smaller than members  12 M 2 . There are four of members  12 M 1  and three of members  12 M 2  in the example of  FIG.  18   , but in general each housing portion may have any suitable number of protruding members (e.g., at least one, at least two, at least five, at least 10, 10-40, fewer than 100, fewer than 75, fewer than 30, fewer than 12, fewer than 3, or other suitable number. Members  12 M 1  and/or  12 M 2  may extend at least 10% of the length of device housing  12 , at least 30%, at least 75%, less than 100%, less than 60%, or other suitable amount. 
     The elongated fingers of housing  12  of  FIG.  18    facilitate sliding of portions  12 - 1  and  12 - 2  relative to each other along the longitudinal axis of the elongated fingers (e.g., along axis  88 , which may run parallel to longitudinal axis  56  of  FIG.  1   ). Display  14  may be supported by members  12 M 1  and  12 M 2  in both unexpanded and expanded configurations. When portions  12 - 1  and  12 - 2  are moved towards each other (e.g., by sliding portions  12 - 1  and  12 - 2  towards each other along axis  88 ), housing  12  may have an unexpanded configuration of the type shown in  FIG.  18   . When it is desired to expand display  14 , portions  12 - 1  and  12 - 2  may be moved away from each other (e.g., portions  12 - 1  and  12 - 2  may be slid apart along axis  88 ). This places housing  12  (and overlapping display  14  of device  10 ) in an expanded configuration, as shown by expanded housing  12  of  FIG.  19   . 
       FIG.  20    shows how portions of housing  12  (e.g., portion  12 - 1 ) may have slots or other openings (see, e.g., illustrative housing opening  86 ) to accommodate display  14 . When device  10  is in its unexpanded state, display  14  may be doubled back on itself one or more times or otherwise stowed in the interior of housing portion  12 - 1  to reduce the exposed length of display  2 . When device  10  is expanded, display  14  may be pulled out of the interior of portion  12 - 1  through opening  86  and may be supported on the outer surfaces of members  12 M 1  and  12 M 2 . Recesses  12 R 1  for receiving members  12 M 2  may be open to the interior of portion  12 - 1  or may be formed in the surface of a housing wall that covers the upper surface of portion  12 - 1 . 
     In arrangements of the type shown in  FIG.  20   , housing portions  12 - 1  and  12 - 2  may be unequal in size (e.g., the interior volume of portion  12 - 2  may be less than the interior volume of portion  12 - 1  as shown in  FIG.  20   ). In the illustrative configuration of  FIG.  21   , housing portions  12 - 1  and  12 - 2  have sizes that are equal or nearly equal (e.g., the interior volume and/or exterior volume occupied by portions  12 - 1  and  12 - 2  may differ by less than 25%, less than 15%, or less than 8%). In this type of arrangement, portion  12 - 1  may be used for display storage when display  14  is unexpanded and portion  12 - 2  may be used to housing a battery, control circuitry, and other electronic components and/or other sets of components may be stored in housing portion  12 - 1  and/or housing portion  12 - 2 . 
     In the arrangement of  FIG.  21   , members  12 M 2  are thin strip-shaped protrusions that are received within shallow mating recesses  12 R 1 . If desired, members  12 M 2  may occupy some or all of the thickness of housing  12 .  FIG.  22    is a perspective view of housing  12  in a configuration in which interdigitated members  12 M 1  and  12 M 2  extend through the entire thickness of housing  12 . Housing portion  12 - 1  includes through-housing recesses such as recesses  12 R 1  to receive members  12 M 2  and housing portion  12 - 2  includes through-housing recesses such as recesses  12 R 2  to receive members  12 M 1 . 
     Another interlocking sliding arrangement for housing  12  is shown in  FIG.  23   . As shown in  FIG.  23   , housing portion  12 - 1  may be substantially larger than housing portion  12 - 2 , which allows a portion of display  14  and other electrical components to be stored in housing portion  12 - 1  when display  14  is in its unexpanded state (e.g., display  14  may have a portion that is stored with two or three layers that are doubled back on each other using one or more rollers or other structures, as described in connection with  FIGS.  10 ,  11 , and  12   ). Components may also be stored in housing portion  12 - 2  or housing portion  12 - 2  may serve primarily as a supporting and connecting member that helps secure the ends of elongated members  12 M 2 . 
       FIG.  24    is a top view of housing  12  in an illustrative configuration in which telescoping supporting members (e.g., supporting housing portions  12 - 3  of  FIG.  9   , which may be fully or partially formed from structures in portion  12 - 1  and/or  12 - 2 ) have been formed from tubular members  12 A (coupled to portion  12 - 1 ) and nesting tubular members  12 B (coupled to portion  12 - 2 ). Members  12 A and  12 B may be relatively strong supporting members and may have a different shape than members  12 M 1  and  12 M 2 . For example, members  12 M 1  and  12 M 2  may be formed from thin strip-shaped protrusions that have relatively large surface areas for supporting display  14  in a planar shape, whereas the telescoping support structures formed from members  12 A and  12 B may have tubular shapes or other suitable shapes. Members  12 A and  12 B in this type of arrangement may not be used in directly supporting display  14 , but may be sufficiently strong to help maintain portions  12 - 1  and  12 - 2  in a desired angular relationship with respect to each other while allowing members  12 - 1  and  12 - 2  to be slid towards and away from each other to adjust the size of display  14  (e.g., to adjust the size of the portion of display  14  that is visible to a user on front face F of device  10 ). 
     The interlocked structures of portions  12 - 1  and  12 - 2  may have shapes of the types shown in  FIGS.  25 ,  26 ,  27 , and  28    and/or other suitable shapes. 
     In the example of  FIG.  25   , members  12 M 2  are elongated (extending into the page parallel to the Y axis) and have thin strip-shaped configurations. The thickness of members  12 M 2  in the Z dimension may be less than the width of members  12 M 2  in the X dimension. Members  12 M 2  may be received for sliding movement within shallow recesses in the surface of portion  12 - 1 . Portions of housing portion  12 - 1  that lie between the shallow recesses may form members  12 M 1 . The shapes of the sidewalls of members  12 M 2  and the corresponding shapes of the sidewalls of the recesses that receive members  12 M 2  may have triangular ross-sectional shapes or other shapes that help retain members  12 M 2  within portion  12 - 1  and prevent members  12 M 2  from being pulled out of the recesses upwards along the Z dimension while allowing members  12 M 2  and the rest of portion  12 - 2  to slide with respect to portion  12 - 1  (e.g., along the Y dimension). Lubricious coatings and/or lubricant that is separate from members  12 M 1  and  12 M 2  may be provided to reduce sliding friction (if desired). Display  14  may be coupled directly to the exposed surfaces of members  12 M 2  or a support layer (e.g., a thin flexible sheet) that forms a rear backing layer for display  14  may be coupled to the exposed surfaces of members  12 M 2 . Solid and/or segmented or grid-shaped sheets may be used as support layers. 
     In the example of  FIG.  26   , members  12 M 1  have recesses that receive lateral protrusions  12 M 2 ′ of members  12 M 2 . Protrusions  12 M 2 ′ may have shapes that help retain members  12 M 2  within the recesses formed in portion  12 - 1  while allowing members  12 M 2  to slide relative to portion  12 - 1 . 
     Another illustrative arrangement is shown in  FIG.  27   . In the configuration of  FIG.  27   , members  12 M 2  have downwardly extending protrusions  12 M 2 ″ that are received within corresponding recesses in portion  12 - 1 . As with the illustrative arrangements of  FIGS.  25  and  26   , members  12 M 2  and other structures in portion  12 - 2  and the structures of portion  12 - 1  may be configured to retain members  12 M 2  in desired positions in the X and Z dimensions while allowing members  12 M 2  to slide with respect to portion  12 - 1  along the Y dimension (e.g., parallel to the longitudinal axis of device  10  and/or other suitable direction). Display  14  may be coupled directly to the exposed surfaces of members  12 M 2  (e.g., using adhesive, etc.) and/or a supporting layer that is attached to the rear surface of display  14  may be coupled to members  12 M 2 . 
     In the arrangement of  FIG.  28   , portion  12 - 2  includes a housing layer that is coupled to a series of protrusions  12 F. Protrusions  12 F and the other protrusions associated with housing portion  12 - 2  such as protrusions  12 M 2 ″ of  FIG.  27   , protrusions  12 M 2 ′ of  FIG.  26   , and/or the protrusions on the opposing edges of each of members  12 M 2  of  FIG.  25   , may extend in a continuous strip along the entire length (or nearly the entire length) of elongated members  12 M or, if desired, protrusions  12 F and other elongated member protrusions (see, e.g.,  FIGS.  25 ,  26   , and  27 ) may be formed at a series of discrete locations along the lengths of members  12 M 2 . 
     In the examples of  FIGS.  25 ,  26 ,  27 , and  28   , members  12 M 2  of portion  12 - 2  have been provided with protruding portions that interlock with corresponding recesses in portion  12 - 1 . These arrangements, in which the elongated members of one housing portion slidably engage with recesses and/or elongated members of another housing portion, allow housing  12  to be slidably moved between expanded and unexpanded states. If desired, portions  12 - 1  and  12 - 2  may be configured to interlock while permitting sliding motion between portions  12 - 1  and  12 - 2  using other engagement structures. For example, members  12 M 2  may contain recesses that receive corresponding protrusions from portion  12 - 1 . 
     Input-output devices  34  (e.g., electrical components) such as optical sensors and other optical components (e.g., light-emitting devices), may be mounted on elongated housing members  12 M 1  and/or  12 M 2 , may be embedded within elongated housing members  12 M 1  and/or  12 M 2 , may be mounted behind members  12 M 1  and/or  12 M 2 , may be mounted in interior portions of housing  12 , and/or may be coupled to other portions of device  10 . Illustrative locations for devices  34  are shown by illustrative locations  34 ′,  34 ″,  34 ″, and  34 ′ of  FIG.  29   . In each of these positions, one or more input-output devices  34  may emit light, may detect light, and/or may otherwise receive environmental measurements, gather user input, and/or or provide output to a user. In arrangements in which input-output devices  34  are mounted behind a housing wall (e.g., behind a portion of an elongated housing member or other housing structure), one or more windows may be formed in the housing wall. Windows may be configured to pass light (e.g., transparent window structures in a housing may be formed to allow light to be emitted and/or detected by an optical component), may be configured to pass radio-frequency signals (e.g., to accommodate an antenna), and/or may otherwise be formed from an opening and/or an optically transparent structure, radio-transparent structure, and/or other window structure in housing  12 . If desired, light and/or other signals associated with operation of input-output devices  34  may pass through openings or other window structures (e.g., transparent window regions) in display  14 . 
       FIG.  30    is a perspective view of an illustrative expandable electronic device housing structure. In the example of  FIG.  30   , elongated members  12 M 2  have been formed from thin flexible strips that accommodate bending of the tips of members  12 M 2  around curved sidewall W at the curved end of housing portion  12 - 1  (e.g., the edge of housing portion  12 - 1  facing away from housing portion  12 - 2 ). The curved end of housing portion  12 - 1  may have recesses that receive members  12 M 2  and that guide members  12 M 2  around bend axis  94 . Members  12 M 2  of  FIG.  30    and the other FIGS. may be solid pieces of polymer, metal, other materials, and/or combinations of these materials, and/or may each have optional linked segments such as illustrative segments  12 G of  FIG.  30    to enhance flexibility. Members  12 M 2  and portion  12 - 1  may, if desired, have engagement structures (see, e.g.,  FIGS.  25 ,  26 ,  27 , and  28   ) that help retain members  12 M 2  in desired positions relative to portion  12 - 1  and that help align portions  12 - 1  and  12 - 2  at a desired orientation as portions  12 - 1  and  12 - 2  are slid towards and away from each other. Flexible display  14  may be coupled to the exposed surfaces of members  12 M 2 . 
     When device  10  is in an unexpanded configuration, display  14  may have a first portion that lies flat on the upper surface of portion  12 - 2  including the upper surfaces of members  12 M 2  on front face F of device  10 . Display  14  may also have a second portion that wraps around curved sidewall W and a third portion that extends along some or all of rear face R. When expanded, members  12 M 2  slide out of the tracks formed from the recesses in portion  12 - 1  and portion  12 - 2  slides away from portion  12 - 1 . In its fully expanded state, the second and third portions of display  14  move around to front face F from sidewall W and rear face R by following sliding members  12 M 2 . 
     In the perspective view of  FIG.  30   , display  14  of device  10  is not present.  FIG.  31    is a cross-sectional side view of device  10  of  FIG.  31    taken along line  91  of  FIG.  30    and viewed in direction  93  in an arrangement in which display  14  has been attached to members  12 M 2 . This allows display  14  to flex as display  14  travels from rear face R to front face F of device  10  while sliding of portion  12 - 2  away from portion  12 - 1  for display expansion. Display  14  (in this example) covers all of front face F and curved sidewall W and part of rear face R of device  10  when display  14 , device  10 , and housing  12  are unexpanded as shown in  FIG.  31   . When expanded, display  14  slides to the front of device  10  in direction  96  in response to movement of portion  12 - 2  in direction  52 , allowing the size of display  14  to be enlarged for viewing by a user such as user  98  who is viewing device  10  in direction  100  (e.g., display  14  is placed in an expanded viewable area configuration). If desired, larger portions of display  14  may overlap rear face R when display  14  is unexpanded or smaller portions of display  14  may be present on front face F and curved sidewall W without being present on rear face R when display  14  is unexpanded. 
     If desired, separate display panels may be used to form display  14  in a device with a sliding housing. A cross-sectional view of device  10  viewed along longitudinal axis  56  in an arrangement in which display  14  has overlapping and engaging sliding display portions is shown in  FIG.  32   . As shown in  FIG.  32   , device housing  12  may have first portion  12 - 1  and second portion  12 - 2 . First portion  12 - 1  and/or second portion  12 - 2  may have interior portions that contain control circuitry, input-output devices, batteries, and other electrical components. Portions  12 - 1  and  12 - 2  may have slidable engagement structures. The engagement structures may be formed from overlapping and gripping sidewall structures in portion  12 - 2  that overlap the sidewalls of portion  12 - 1  and that hold portions  12 - 1  and  12 - 2  together while allowing portions  12 - 1  and  12 - 2  to slide with respect to each other along longitudinal axis  56 . Portions  12 - 1  and  12 - 2  may be electrically connected using flexible circuits, wires, sliding electrical contacts, wireless communications, and/or other communications path arrangements that allow circuitry in portions  12 - 1  and  12 - 2  to interact while permitting sliding motion between portions  12 - 1  and  12 - 2 . In some configurations, circuitry in portions  12 - 1  and  12 - 2  may operate without communicating with each other. 
     Display  14  may have a lower portion such as portion  14 B (e.g., a first display portion or first display) that is coupled to the front face of housing portion  12 - 1  and may have an upper portion such as portion  14 T that is coupled to the front face of housing portion  12 - 2 . When in the unexpanded state of  FIG.  33   , display portion  14 T is viewable to a user and display portion  14 B is not visible due to the overlap of portion  14 B by portion  14 T. When in the expanded state of  FIG.  34    (e.g., after portion  12 - 2  has been slid away from portion  12 - 1  in direction  52 ), both display portion  14 T and display portion  14 B of display  14  are viewable by the user on the front face of device  10 . This offers the user of device  10  an enlarged viewing area. If desired, the presentation of content on portions  14 B and  14 T can be coordinated so that display portions  14 B and  14 T operate as a seamless unitary display surface. Configurations in which display portions  14 B and  14 T display separate images that do not mate with each other along the seam between portions  14 B and  14 T may also be used. 
     As described above, one aspect of the present technology is the gathering and use of information such as sensor information (e.g., optical sensor information). The present disclosure contemplates that in some instances, this gathered data may include personal information data that uniquely identifies or can be used to contact or locate a specific person. Such personal information data can include demographic data, location-based data, telephone numbers, email addresses, twitter ID&#39;s, home addresses, data or records relating to a user&#39;s health or level of fitness (e.g., vital signs measurements, medication information, exercise information), date of birth, eyeglasses prescription, username, password, biometric information, or any other identifying or personal information. 
     The present disclosure recognizes that the use of such personal information, in the present technology, can be used to the benefit of users. For example, the personal information data can be used to deliver targeted content that is of greater interest to the user. Accordingly, use of such personal information data enables users to calculated control of the delivered content. Further, other uses for personal information data that benefit the user are also contemplated by the present disclosure. For instance, health and fitness data may be used to provide insights into a user&#39;s general wellness, or may be used as positive feedback to individuals using technology to pursue wellness goals. 
     The present disclosure contemplates that the entities responsible for the collection, analysis, disclosure, transfer, storage, or other use of such personal information data will comply with well-established privacy policies and/or privacy practices. In particular, such entities should implement and consistently use privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining personal information data private and secure. Such policies should be easily accessible by users, and should be updated as the collection and/or use of data changes. Personal information from users should be collected for legitimate and reasonable uses of the entity and not shared or sold outside of those legitimate uses. Further, such collection/sharing should occur after receiving the informed consent of the users. Additionally, such entities should consider taking any needed steps for safeguarding and securing access to such personal information data and ensuring that others with access to the personal information data adhere to their privacy policies and procedures. Further, such entities can subject themselves to evaluation by third parties to certify their adherence to widely accepted privacy policies and practices. In addition, policies and practices should be adapted for the particular types of personal information data being collected and/or accessed and adapted to applicable laws and standards, including jurisdiction-specific considerations. For instance, in the United States, collection of or access to certain health data may be governed by federal and/or state laws, such as the Health Insurance Portability and Accountability Act (HIPAA), whereas health data in other countries may be subject to other regulations and policies and should be handled accordingly. Hence different privacy practices should be maintained for different personal data types in each country. 
     Despite the foregoing, the present disclosure also contemplates embodiments in which users selectively block the use of, or access to, personal information data. That is, the present disclosure contemplates that hardware and/or software elements can be provided to prevent or block access to such personal information data. For example, the present technology can be configured to allow users to select to “opt in” or “opt out” of participation in the collection of personal information data during registration for services or anytime thereafter. In another example, users can select not to provide certain types of user data. In yet another example, users can select to limit the length of time user-specific data is maintained. In addition to providing “opt in” and “opt out” options, the present disclosure contemplates providing notifications relating to the access or use of personal information. For instance, a user may be notified upon downloading an application (“app”) that their personal information data will be accessed and then reminded again just before personal information data is accessed by the app. 
     Moreover, it is the intent of the present disclosure that personal information data should be managed and handled in a way to minimize risks of unintentional or unauthorized access or use. Risk can be minimized by limiting the collection of data and deleting data once it is no longer needed. In addition, and when applicable, including in certain health related applications, data de-identification can be used to protect a user&#39;s privacy. De-identification may be facilitated, when appropriate, by removing specific identifiers (e.g., date of birth, etc.), controlling the amount or specificity of data stored (e.g., collecting location data at a city level rather than at an address level), controlling how data is stored (e.g., aggregating data across users), and/or other methods. 
     Therefore, although the present disclosure broadly covers use of personal information data to implement one or more various disclosed embodiments, the present disclosure also contemplates that the various embodiments can also be implemented without the need for accessing such personal information data. That is, the various embodiments of the present technology are not rendered inoperable due to the lack of all or a portion of such personal information data. 
     The foregoing is illustrative and various modifications can be made to the described embodiments. The foregoing embodiments may be implemented individually or in any combination.