PATENT DOCUMENT

Publication Number: US-12114451-B2
Application Number: US-202117538701-A
Country: US
Kind Code: B2

Title: Electronic devices with folding displays having flexible area support structures

Abstract:
A foldable display may have a display cover layer and display panel that bend around a bend axis. The display panel may have an array of pixels configured to display an image through the display cover layer. The display cover layer may be formed from a layer of glass. A recess may be formed in the layer of glass that extends along and overlaps the bend axis. The recess forms a flexible locally thinned portion in the glass that allows the display cover layer to bend. Polymer may be formed in the recess. Stiffening structures such as glass strips and glass beads of one or more diameters may be embedded in the polymer to help resist inward compression of the surface of the display cover layer in the locally thinned region while allowing the display cover layer to bend about the bend axis.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a foldable housing that is configured to bend about a bend axis; 
 a flexible display panel that overlaps the bend axis; and 
 a display cover layer that overlaps the flexible display panel, wherein the display cover layer has an inner surface that faces the flexible display panel and has an opposing outer surface and wherein the display cover layer has a groove extending along the bend axis that forms a locally thinned portion of the display cover layer; 
 polymer in the groove; and 
 stiffening structures comprising particles embedded in the polymer that enhance resistance of the outer surface over the locally thinned portion to inward deformation while allowing the display cover layer to bend about the bend axis. 
 
     
     
       2. The electronic device defined in  claim 1  wherein the particles have a mean diameter that varies as a function of distance through the polymer. 
     
     
       3. The electronic device defined in  claim 2  wherein the particles have a first mean diameter at a first distance into the polymer from the outer surface and wherein the particles have a second mean diameter that is smaller than the first mean diameter at a second distance into the polymer from the outer surface that is larger than the first distance. 
     
     
       4. The electronic device defined in  claim 3  wherein the mean diameter of the particles varies smoothly and continuously as the function of distance through the polymer. 
     
     
       5. The electronic device defined in  claim 3  wherein the mean diameter of the particles is characterized by a stepwise change as the function of distance through the polymer. 
     
     
       6. The electronic device defined in  claim 2  wherein the mean diameter is 0.5 microns to 50 microns. 
     
     
       7. The electronic device defined in  claim 6  wherein the particles comprise glass particles. 
     
     
       8. The electronic device defined in  claim 1  wherein the particles comprise glass beads. 
     
     
       9. The electronic device defined in  claim 8  wherein the glass beads have diameters of 1-50 microns and wherein the polymer contains inorganic nanoparticles of less than 250 nm in diameter. 
     
     
       10. The electronic device defined in  claim 1  wherein the stiffening structures further comprise glass strips. 
     
     
       11. The electronic device defined in  claim 10  wherein the glass strips have rectangular cross-sectional profiles with rounded corners. 
     
     
       12. The electronic device defined in  claim 1  wherein the particles comprise glass beads and the stiffening structures further comprise glass strips. 
     
     
       13. The electronic device defined in  claim 12  wherein the polymer contains nanoparticles with diameters of less than 300 nm at a concentration, wherein the polymer has a first refractive index, wherein the display cover layer has a second refractive index, and wherein the concentration is configured to ensure that the first refractive index and the second refractive index differ by less than 0.05. 
     
     
       14. The electronic device defined in  claim 1  wherein the display cover layer comprises a glass layer and has a non-thinned portion, the electronic device further comprising a polymer coating on the inner surface of the non-thinned portion. 
     
     
       15. The electronic device defined in  claim 14  wherein the polymer coating is an extended portion of the polymer in the groove. 
     
     
       16. The electronic device defined in  claim 14  wherein the polymer coating and the polymer in the groove are different polymer materials. 
     
     
       17. An electronic device, comprising:
 a foldable housing that is configured to bend about a bend axis; 
 a flexible display panel that overlaps the bend axis; 
 a glass display cover layer that overlaps the flexible display panel, wherein the glass display cover layer has an outer surface and has an inner surface facing the flexible display panel and wherein the glass display cover layer has a recess in the inner surface that extends along the bend axis and forms a locally thinned portion of the glass display cover layer; and 
 polymer in the recess that contains glass strips that stiffen the outer surface over the recess while allowing the glass display cover layer to bend about the bend axis, wherein the polymer is interposed between the glass strips and the glass display cover layer. 
 
     
     
       18. The electronic device defined in  claim 17  further comprising glass beads in the polymer. 
     
     
       19. A foldable display, comprising:
 a foldable display panel configured to fold about a bend axis; and 
 a display cover layer that overlaps the foldable display panel, wherein the display cover layer has a recess forming a locally thinned portion of the display cover layer that extends along the bend axis, the display cover layer comprising:
 a first layer of glass that overlaps the foldable display panel; 
 a second layer of glass attached to an inner surface of the first layer of glass by a polymer layer, wherein the second layer of glass has first and second halves separated by a gap that forms the recess; and 
 polymer containing glass stiffening structures in the recess, wherein the polymer is interposed between the glass stiffening structures and the display cover layer. 
 
 
     
     
       20. The foldable display defined in  claim 19  wherein the glass stiffening structures comprise glass beads. 
     
     
       21. The foldable display defined in  claim 20  wherein at least one characteristic of the glass beads varies as a function of distance through the polymer. 
     
     
       22. The foldable display defined in  claim 19  wherein the glass stiffening structures comprise glass strips that extend parallel to the bend axis. 
     
     
       23. The foldable display defined in  claim 22  wherein the glass stiffening structures further comprise glass beads, the foldable display further comprising:
 nanoparticles in the polymer having diameters less than 200 nm; 
 a polymer coating on a surface of the second layer of glass facing the foldable display panel; and 
 an antireflection coating on an outer surface of the first layer of glass facing away from the foldable display panel. 
 
     
     
       24. An electronic device, comprising:
 a foldable housing that is configured to bend about a bend axis; 
 a flexible display panel that overlaps the bend axis; 
 a display cover layer that overlaps the flexible display panel, wherein the display cover layer has an inner surface that faces the flexible display panel and has an opposing outer surface and wherein the display cover layer has a groove extending along the bend axis that forms a locally thinned portion of the display cover layer; 
 polymer in the groove; and 
 dielectric particles embedded in the polymer that enhance resistance of the outer surface over the locally thinned portion to inward deformation while allowing the display cover layer to bend about the bend axis, wherein the dielectric particles have a mean diameter between 0.01 microns and 50 microns and wherein the mean diameter varies as a function of distance through the polymer.

Description:
This application claims the benefit of provisional patent application No. 63/127,690, filed Dec. 18, 2020, and provisional patent application No. 63/166,555, filed Mar. 26, 2021, 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 have displays. Portability may be a concern for some devices, which tends to limit available real estate for displays. 
     SUMMARY 
     An electronic device may be provided with a foldable housing that allows the device to fold and unfold about a bend axis. A flexible display may be mounted in the foldable housing. The flexible display may have an array of pixels forming a display panel. The display panel may be configured to bend along the bend axis as the device is folded. 
     The flexible display may have a display cover layer that overlaps the display panel. The display cover layer may be formed from a layer of glass. A groove-shaped recess may be formed in the layer of glass that runs parallel to the bend axis. The recess forms a flexible locally thinned portion in the glass over the bend axis that allows the display to bend about the bend axis. 
     Polymer may be placed in the recess to help planarize the inner surface of the display cover layer. Stiffening structures such as glass strips and/or glass beads of one or more diameters may be embedded in the polymer to help stiffen the surface of the display cover layer in the locally thinned region so that the outer surface of the display cover layer is not too easily deformed by external pressure from an object such as a stylus. While supporting the outer surface of the display cover layer, the stiffening structures allow the display cover layer to bend satisfactorily about the bend axis. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a schematic diagram of an illustrative electronic device in accordance with an embodiment. 
         FIG.  2    is a perspective view of an illustrative electronic device with a display 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 a cross-sectional side view of an illustrative display having a cover layer with a locally thinned hinge region in accordance with an embodiment. 
         FIG.  5    is a cross-sectional side view of an illustrative locally thinned display cover layer having outer and inner coatings in accordance with an embodiment. 
         FIG.  6    is a cross-sectional side view of an illustrative locally thinned display cover layer with an inner coating that is formed as an integral portion of a recess-filling layer in accordance with an embodiment. 
         FIG.  7    is a cross-sectional side view of an illustrative locally thinned display cover layer with a polymer filler having embedded particles in accordance with an embodiment. 
         FIG.  8    is a graph in which mean particle diameter in an illustrative recess-filling polymer layer has been plotted as a function of distance through the layer in accordance with an embodiment. 
         FIG.  9    is a cross-sectional side view of an illustrative display cover layer with a locally thinned portion in accordance with an embodiment. 
         FIGS.  10  and  11    are cross-sectional side views of illustrative display cover layers with locally thinned areas having polymer with embedded stiffening members in accordance with embodiments. 
         FIG.  12    is a cross-sectional side view of an illustrative stiffening member for adding compression rigidity to a locally thinned portion of a cover layer in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices may be provided with displays. Displays may be used for displaying images for users. Displays may be formed from arrays of light-emitting diode pixels or other pixels. For example, a device may have an organic light-emitting diode display or a display formed from an array of micro-light-emitting diodes (e.g., diodes formed from crystalline semiconductor dies). 
     A schematic diagram of an illustrative electronic device having a display is shown in  FIG.  1   . Device  10  may be a cellular telephone, tablet computer, laptop computer, wristwatch device or other wearable device, a television, a stand-alone computer display or other monitor, a computer display with an embedded computer (e.g., a desktop computer), a system embedded in a vehicle, kiosk, or other embedded electronic device, a media player, or other electronic equipment. Configurations in which device  10  is a cellular telephone, tablet computer, or other portable electronic device may sometimes be described herein as an example. This is illustrative. Device  10  may, in general, be any suitable electronic device with a display. 
     Device  10  may include control circuitry  20 . Control circuitry  20  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  20  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. During operation, control circuitry  20  may use a display and other output devices in providing a user with visual output and other output. 
     To support communications between device  10  and external equipment, control circuitry  20  may communicate using communications circuitry  22 . Circuitry  22  may include antennas, radio-frequency transceiver circuitry (wireless transceiver circuitry), and other wireless communications circuitry and/or wired communications circuitry. Circuitry  22 , which may sometimes be referred to as control circuitry and/or control and communications circuitry, may support bidirectional wireless communications between device  10  and external equipment over a wireless link (e.g., circuitry  22  may include radio-frequency transceiver circuitry such as wireless local area network transceiver circuitry configured to support communications over a wireless local area network link, near-field communications transceiver circuitry configured to support communications over a near-field communications link, cellular telephone transceiver circuitry configured to support communications over a cellular telephone link, or transceiver circuitry configured to support communications over any other suitable wired or wireless communications link). Wireless communications may, for example, be supported over a Bluetooth® link, a WiFi® link, a wireless link operating at a frequency between 6 GHz and 300 GHz, a 60 GHz link, or other millimeter wave link, cellular telephone link, wireless local area network link, personal area network communications link, or other wireless communications link. Device  10  may, if desired, include power circuits for transmitting and/or receiving wired and/or wireless power and may include batteries or other energy storage devices. For example, device  10  may include a coil and rectifier to receive wireless power that is provided to circuitry in device  10 . 
     Device  10  may include input-output devices such as devices  24 . Input-output devices  24  may be used in gathering user input, in gathering information on the environment surrounding the user, and/or in providing a user with output. Devices  24  may include one or more displays such as display  14 . Display  14  may be an organic light-emitting diode display, a liquid crystal display, an electrophoretic display, an electrowetting display, a plasma display, a microelectromechanical systems display, a display having a pixel array formed from crystalline semiconductor light-emitting diode dies (sometimes referred to as microLEDs), and/or other display. Configurations in which display  14  is an organic light-emitting diode display or microLED display are sometimes described herein as an example. 
     Display  14  may have an array of pixels configured to display images for a user. The pixels may be formed as part of a display panel that is bendable. This allows device  10  to be folded and unfolded about a bend axis. For example, a flexible (bendable) display in device  10  may be folded so that device  10  may be placed in a compact shape for storage and may be unfolded when it is desired to view images on the display. 
     Sensors  16  in input-output devices  24  may include force sensors (e.g., strain gauges, capacitive force sensors, resistive force sensors, etc.), audio sensors such as microphones, touch and/or proximity sensors such as capacitive sensors (e.g., a two-dimensional capacitive touch sensor integrated into display  14 , a two-dimensional capacitive touch sensor overlapping display  14 , and/or a touch sensor that forms a button, trackpad, or other input device not associated with a display), and other sensors. If desired, sensors  16  may include optical sensors such as optical sensors that emit and detect light, ultrasonic sensors, optical touch sensors, optical proximity sensors, and/or other touch sensors and/or proximity sensors, monochromatic and color ambient light sensors, image sensors, fingerprint sensors, temperature sensors, sensors for measuring three-dimensional non-contact gestures (“air gestures”), pressure 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), health sensors, radio-frequency sensors, depth sensors (e.g., structured light sensors and/or depth sensors based on stereo imaging devices that capture three-dimensional images), optical sensors such as self-mixing sensors and light detection and ranging (lidar) sensors that gather time-of-flight measurements, humidity sensors, moisture sensors, gaze tracking sensors, and/or other sensors. In some arrangements, device  10  may use sensors  16  and/or other input-output devices to gather user input. For example, buttons may be used to gather button press input, touch sensors overlapping displays can be used for gathering user touch screen input, touch pads may be used in gathering touch input, microphones may be used for gathering audio input, accelerometers may be used in monitoring when a finger contacts an input surface and may therefore be used to gather finger press input, etc. 
     If desired, electronic device  10  may include additional components (see, e.g., other devices  18  in input-output devices  24 ). The additional components may include haptic output devices, audio output devices such as speakers, light-emitting diodes for status indicators, light sources such as light-emitting diodes that illuminate portions of a housing and/or display structure, other optical output devices, and/or other circuitry for gathering input and/or providing output. Device  10  may also include a battery or other energy storage device, connector ports for supporting wired communication with ancillary equipment and for receiving wired power, and other circuitry. 
       FIG.  2    is a perspective view of electronic device  10  in an illustrative configuration in which device  10  is a portable electronic device such as a cellular telephone or tablet computer. As shown in  FIG.  2   , device  10  may have a display such as display  14 . Display  14  may cover some or all of the front face of device  10 . Touch sensor circuitry such as two-dimensional capacitive touch sensor circuitry may be incorporated into display  14 . 
     Display  14  may be mounted in housing  12 . Housing  12  may form front and rear housing walls, sidewall structures, and/or internal supporting structures (e.g., a frame, an optional midplate member, etc.) for device  10 . Glass structures, transparent polymer structures, and/or other transparent structures that cover display  14  and other portions of device  10  may provide structural support for device  10  and may sometimes be referred to as housing structures. For example, a transparent housing portion such as a glass or polymer housing structure that covers and protects a pixel array in display  14  may serve as a display cover layer for the pixel array while also serving as a housing wall on the front face of device  10 . In configurations in which a display cover layer is formed from glass, the display cover layer may sometime be referred to as a display cover glass or display cover glass layer. The portions of housing  12  on the sidewalls and rear wall of device  10  may be formed from glass or other transparent structures and/or opaque structures. Sidewalls and rear wall structures may be formed as extensions to the front portion of housing  12  (e.g., as integral portions of the display cover layer) and/or may include separate housing wall structures. 
     Housing  12  may have flexible structures (e.g., bendable housing wall structures) and/or hinge structures such as hinge  30 . Hinge  30  may have a hinge axis aligned with device bend axis  28 . Hinge  30  and/or flexible housing structures that overlap bend axis  28  may allow housing  12  to bend about bend axis  28 . For example, housing  12  may have a first portion on one side of bend axis  28  and a second portion on an opposing side of bend axis  28  and these two housing portions may be coupled by hinge  30  for rotational motion about axis  28 . 
     As housing  12  is bent about bend axis  28 , the flexibility of display  14  allows display  14  to bend about axis  28 . In an illustrative configuration, housing  12  and display  14  may bend by 180°. This allows display  14  to be folded back on itself (with first and second outwardly-facing portions of display  14  facing each other). The ability to place device  10  in a folded configuration in this way may help make device  10  compact so that device  10  can be stored efficiently. When it is desired to view images on display  14 , device  10  may be unfolded about axis  28  to place device  10  in the unfolded configuration of  FIG.  2   . This allows display  14  to lie flat and allows a user to view flat images on display  14 . The ability to fold display  14  onto itself allows device  10  to exhibit an inwardly folding behavior. Display  14  may be sufficiently flexible to allow device  10  to be folded outwardly and/or inwardly. 
     Device  10  of  FIG.  2    has a rectangular outline (rectangular periphery) with four corners. As shown in  FIG.  2   , a first pair of parallel edges (e.g., the left and right edges of device  10  in the example of  FIG.  2   ) may be longer than a second pair of parallel edges (e.g., the upper and lower edges of device  10  of  FIG.  2   ) that are oriented at right angles to the first pair of parallel edges. In this type of configuration, housing  12  is elongated along a longitudinal axis that is perpendicular to bend axis  28 . Housing  12  may have other shapes, if desired (e.g., shapes in which housing  12  has a longitudinal axis that extends parallel to bend axis  28 ). With an arrangement of the type shown in  FIG.  2   , the length of device  10  along its longitudinal axis may be reduced by folding device  10  about axis  28 . 
       FIG.  3    is a cross-sectional side view of an illustrative foldable electronic device. Device  10  of  FIG.  3    may bend about bend axis  28 . Bend axis  28  may be aligned with display cover layer  14 CG or other structures in device  10 . For example, bend axis  28  may pass through a portion of display cover layer  14 CG or may be located above or below layer  14 CG. 
     As shown in  FIG.  3   , display  14  includes an array of pixels P forming display panel  14 P under an inwardly facing surface of display cover layer  14 CG. Display panel  14 P may be, for example, a flexible organic light-emitting diode display or a microLED display in which light-emitting pixels are formed on a flexible substrate layer (e.g., a flexible layer of polyimide or a sheet of other flexible polymer). Flexible support layer(s) for display  14  may also be formed from flexible glass, flexible metal, and/or other flexible structures. 
     Display cover layer  14 CG may be formed from polymer, glass, crystalline materials such as sapphire, other materials, and/or combinations of these materials. To enhance flexibility, a portion of layer  14 CG that overlaps and extends along bend axis  28  may be locally thinned (e.g., this portion may be thinned relative to portions of layer  14 CG that do not overlap bend axis  28 ). The thickness of layer  14 CG (e.g., the non-thinned portions of layer  14 CG) may be 50-200 microns, 70-150 microns, 100-200 microns, 100-600 microns, at least 100 microns, at least 200 microns, less than 600 microns, less than 400 microns, less than 250 microns, less than 150 microns, less than 100 microns, at least 50 microns, or other suitable thickness. 
     In the example of  FIG.  3   , housing  12  has a portion on rear face R that forms a rear housing wall and has side portions forming sidewalls  12 W. The rear housing wall of housing  12  may form a support layer for components in device  10 . Housing  12  may also have one or more interior supporting layers (e.g., frame structures such as an optional midplate, etc.). These interior supporting layers and the rear housing wall may have first and second portions that are coupled to opposing sides of a hinge that is aligned with bend axis  28  (see, e.g., hinge  30  of  FIG.  2   ) or may be sufficiently flexible to bend around bend axis  28 . 
     Electrical components  32  may be mounted in the interior of device  10  (e.g., between display  14  and the rear of housing  12 . Components  32  may include circuitry of the type shown in  FIG.  1    (e.g., control circuitry  20 , communications circuitry  22 , input-output devices  24 , batteries, etc.). Display  14  may be mounted on front face F of device  10 . When device  10  is folded about axis  28 , display cover layer  14 CG, display panel  14 P, and the other structures of device  10  that overlap bend axis  28  may flex and bend to accommodate folding. 
     The outer and/or inner surfaces of display cover layer  14 GC may be provided with coatings. These coatings may include, for example, antireflection coatings, anti-scratch coatings, anti-smudge coatings, and/or other coating layers. Consider, as an example, the cross-sectional side view of display cover layer  14 CG of  FIG.  4   . As shown in  FIG.  4   , display cover layer may have an outer surface (outwardly facing surface) such as surface  40  and an opposing inner surface (inwardly facing surface) such as surface  42 . A strip-shaped region of display cover layer  14 CG that overlaps and runs parallel to bend axis  28  may be locally thinned (e.g., a groove or other recess that runs parallel to bend axis  28  may be formed in layer  14 CG to form locally thinned portion  44  of layer  14 CG). Locally thinned portion  44  of layer  14 CG may be thinner than other portions of layer  14 CG such as non-thinned portions  46  (which may be, for example, planar glass layer portions of layer  14 CG). The presence of portion  44  in display cover layer  14 CG may facilitate bending of display cover layer  14 CG about bend axis  28 . 
     To help planarize inner surface  42  and thereby facilitate mounting of display panel  14 P against inner surface  42  (e.g., with a layer of adhesive), the elongated recess (groove) in the inner surface of layer  14 CG that forms thinned portion  44  may be filled with polymer  50 . Polymer  50  may be sufficiently flexible to bend about bend axis  28  when device  10  is opened and closed. The refractive index of polymer  50  may be matched to that of display cover layer  14 CG to help minimize light reflections (e.g., by incorporating inorganic nanoparticles in polymer  50 ). For example, at a wavelength of 500 nm, the refractive index of polymer  50  may differ from that of layer  14 CG by less than 0.15, less than 0.1, or less than 0.05 (as examples). 
     Coating layers  52  may be formed on outer surface  40 . Coating layers  52  may include, for example, anti-scratch layers (sometimes referred to as hard coats), protective polymer layers, anti-smudge layers, anti-fog layers, antireflection layers, anti-static layers, adhesion layers, and/or other coatings. In some configurations, each of these functions may be implemented using a separate respective coating layer. In other configurations, a single layer may serve multiple functions. In general, coatings such as coatings  52  may be formed on outer surface  40  and/or inner surface  42 . In the illustrative configuration of  FIG.  4   , coatings  52  are formed on outer surface  40 . 
     Coatings  52  may be provided in any suitable order. As one example, the lowermost coating of coatings  52  (e.g., a coating layer formed directly on surface  40  of  FIG.  4   ) may be a hard coat or other anti-scratch layer that helps prevent scratches that could damage layer  14 CG. An antireflection coating may be formed on top of the anti-scratch layer. The antireflection layer may be a thin-film interference filter antireflection coating containing a stack of thin-film layers such as dielectric sublayers of alternating refractive index. One of the thin-film layers may be a conductive layer such as a transparent semiconductor layer (e.g., an indium tin oxide layer) that serves as an antistatic layer. An anti-smudge coating or anti-fog coating may be formed on top of the antireflection layer. Anti-smudge coatings (e.g., hydrophobic polymer coatings) may help reduce fingerprints and other undesired marks on the surfaces of display  14 . An example of an anti-smudge coating is a fluoropolymer coating (e.g., a fluoropolymer formed from evaporated perfluoropolyether) that serves as an oleophobic layer. Fluoropolymers can be adhered to underlying coating layers using an intervening adhesion layer. 
     As shown in  FIG.  5   , the recess in display cover layer  14 CG that forms locally thinned portion  44  may have a tapered cross-sectional shape. As shown in  FIG.  5   , for example, the top portion of the recess may be characterized by a width W 1  that is narrower than the width W 2  of the lower portion of the recess. This type of arrangement may help avoid abrupt transitions in cover glass thickness and may therefore help reduce stress concentrations while visually obscuring the presence of the recess. To help protect display cover layer  14 CG (e.g., to avoid handling-induced defects), one or more coating layers may be formed on inner surface  42 . As shown in  FIG.  5   , for example, protective coating layer  54  (e.g., a polymer layer) may be formed on inner surface  42 . Layer  54  may have any suitable thickness (e.g., at least 0.05 microns, at least 0.1 microns, at least 0.4 microns, at least 2 microns, at least 5 microns, less than 50 microns, less than 20 microns, less than 7 microns, less than 3 microns, or other suitable thickness). If desired, a protective polymer layer such as layer  54  may be formed on outer surface  40  (e.g., one of layers  52  of  FIG.  4    may be a protective polymer layer such as layer  54 ). 
     Protective layer  54  may be formed on inner surface  42  by depositing polymer  50  and layer  54  separately (using the same polymer material for both polymer  50  and layer  54  or using different polymers for polymer  50  and layer  54 ). As an example, polymer  50  may be deposited in the recess forming thinned portion  44  and cured before depositing and curing a protective polymer layer over polymer  50  and non-thinned areas of inner surface  42 . 
     In another illustrative arrangement, the protective layer on inner surface  42  may be formed as an integral portion of the polymer filling the recess in layer  14 CG. As shown in  FIG.  6   , for example, the same polymer may be used in filling the recess under thinned portion  44  (polymer  50 ) and in forming the protective coating on surface  42  (polymer  50 ′). Polymer  50  and  50 ′ in this type of arrangement may be deposited by coating a liquid polymer material onto inner surface  42  followed by application of heat, light (e.g., ultraviolet light), and/or catalyst to promote polymer curing. 
     During use of device  10 , a computer stylus, fingertip, or other external object may press against outer surface  40  of display cover layer  14 CG (e.g., to supply touch input to a touch sensor that lies between display panel  14 P and the opposing inner surface of display cover layer  14 CG or to supply touch input to a touch sensor that is formed as part of display panel  14 P). Thinned portion  44  of display cover layer  14 CG is preferably sufficiently flexible to allow display cover layer  14 CG to be bent about bend axis  28 . At the same time, it may be desirable to prevent the region of surface  40  that overlaps bend axis  28  from being too easily depressed inwardly, as this may create an undesirable detectable difference in the stiffness of outer surface  40  as an external object moves across bend axis  28 . To help prevent excessive inward compression of surface  40  in the area of display cover layer  14 CG that overlaps thinned portion  44 , stiffening structures that are separate from display cover layer  14 CG may be incorporated into polymer  50  in the recess under thinned portion  44 . These stiffening structures may be particles or may be elongated members (e.g., elongated strips of material, rods, etc.). The material that forms the stiffening structures may be glass, polymer, ceramic, crystalline material such as sapphire, and/or other rigid material (e.g., one or more materials that are have a higher modulus of elasticity (and are therefore stiffer) than polymer  50 . By incorporating structures that are more rigid than polymer  50  into polymer  50 , the stiffness of the thinned portion of layer  14 CG (e.g., resistance to localized inward compression) may be locally enhanced, while continuing to allow display  14  to bend freely about axis  28 . 
     Consider, as an example, the arrangement of  FIG.  7   . As shown in  FIG.  7   , stiffening structures such as stiffening particles  60  may be incorporated into polymer  50  within the recess under thinned portion  44  of display cover layer  14 CG. Particles  60  may be spheres or particles of other shapes and may be formed from a material such as glass with a modulus of elasticity that is greater than that of polymer  50  (e.g., particles  60  may be glass beads). This stiffens polymer  50  and help prevent the portion of surface  40  that lies above thinned portion  44  from being too easily depressed (e.g., too easily locally deformed inward) due to pressure on surface  40  from the tip of a stylus or other external object. At the same time, because particles  60  are not directly connected to each other by any rigid structures (e.g., because there is a portion of polymer  50  between adjacent particles), particles  60  are free to move relative to each other while polymer  50  is flexed. As a result, layer  14 CG and polymer  50  may still bend freely about bend axis  28 . 
     Particles  60  may be any suitable size. Particles may, as an example, have diameters (e.g., a mean diameter) of at least 0.1 microns, at least 0.2 microns, at least 0.3 microns, at least 0.5 microns, at least 1 microns, at least 2 microns, at least 5 microns, at least 25 microns, 0.2-10 microns, 1-20 microns, 1-50 microns, 0.5-50 microns, less than 100 microns, less than 50 microns, less than 25 microns, less than 12 microns, less than 6 microns, or less than 2.5 microns (as examples). 
     To help match the refractive index of polymer  50  to that of display cover layer  14 CG, it may be desirable to include index-matching particles  62  in polymer  50  in addition to including optional stiffening structures such as stiffening particles  60  or other stiffening structures. Index-matching particles  62  may, as example, be formed from particles of inorganic dielectric (e.g., silica, metal oxides such as zirconia particles, alumina particles, titanic particles, etc.). Such index-matching particles may have nanometer-scale sizes and may sometimes be referred to as index-matching nanoparticles. Index-matching particles  62  may, as an example, have subwavelength sizes (e.g., diameters of about 10 nm, 1-100 nm, at least 2 nm, less than 300 nm, less than 250 nm, less than 200 nm, less than 150 nm, less than 100 nm, less than 50 nm, less than 40 nm, 1-50 nm, 2-40 nm etc.). The concentration of index-matching particles  62  may be increased to increase the effective refractive index of polymer  50  and may be decreased to decrease the effective refractive index of polymer  50 . In this way, the refractive index of polymer  50  may be matched to that of display cover layer  14 CG and to that of particles  60  or other stiffening structures (e.g., to reduce reflections at the interfaces between polymer  50  and these structures). 
     The diameter of particles  60  may be uniform or particles  60  may include spheres or other particles of different sizes. If desired, the diameter (e.g., mean diameter) of particles  60  may be constant throughout polymer  50 . In arrangements in which the size of particles  60  varies, the diameters of particles  60  may vary as a function of position in polymer  50 . As an example, the diameter (e.g., the mean diameter) of particles  60  may decrease or otherwise vary as a function of distance d from surface  40 . In general, any one or more characteristics of particles  60  may vary as a function of distance d. As shown in the graph of  FIG.  8   , one or more characteristics of particles  60  such as characteristic M may vary continuously (see, e.g., smoothly and continuously decreasing curve  64  of  FIG.  8   ) and/or may vary in a stepwise fashion (see, e.g., stepwise decreasing curve  66  of  FIG.  8   ). Characteristic M may be any suitable particle characteristic(s) such as particle diameter, particle material, particle refractive index, particle shape, the concentration of particles in polymer  50  (e.g., the number of particles per unit volume), and/or other particle characteristic(s). 
     In arrangements in which the diameter of particles  60  decreases as a function of increasing distance through polymer  50  away from surface  42  at the top of the recess in cover layer  14 CG (and therefore as a function of increasing distance from outer surface  40 ), there will be larger particles near the top of the recess (e.g., nearer to outer surface  40 ) that help to stiffen surface  40  and smaller particles near the bottom of the recess (e.g., nearer to the rear of layer  14 CG). The presence of the smaller particles near the bottom of the recess may help make the lower portion of polymer  50  more flexible than the upper portion of polymer  50 . Because the bottom portion of polymer  50  tends to stretch more than the upper portion of polymer  50  as display cover layer  14 CG is bent about bend axis  28  (e.g., when the two halves of display  14  are being folded toward themselves), the use of a graded particle size (e.g., a stiffening scheme in which the mean diameter of particles  60  decreases as a function of increasing distance d) may help provide a desired amount of surface stiffening to the region of surface  40  that overlaps polymer  50  while retaining a desired flexibility in display cover layer  14 CG so that device  10  and display  14  can be folded. Any suitable technique may be used for forming polymer  50  with embedded stiffening structures such as particles  60  having a gradient in size. With an illustrative configuration, a mixture of liquid polymer material containing particles  60  of varying sizes is used to cover thinned region  44  while display cover layer  14 CG is resting with its inner surface facing upwards. In this type of configuration, the force of gravity will tend to separate particles by size, after which the polymer material can be cured. 
     As described in connection with curve  66  of  FIG.  8   , characteristic M of particles  60  may exhibit stepwise variation as a function of distance d. This type of arrangement is shown in the cross-sectional side view of display cover layer  14 CG of  FIG.  9   . In the example of  FIG.  9   , polymer  50  has been formed using a first layer of polymer  50 - 1  containing particles  60  of a first diameter followed by a second layer of polymer  50 - 2  (at greater distance d from surface  40 ) containing particles  60  of a second diameter that is smaller than the first diameter. In this example, polymer  50  was deposited in two layers (e.g., a first layer that was deposited as a liquid and cured and a second layer that was deposited as a liquid on the cured first layer and subsequently cured). Configurations with three or more discrete layers each having a different size of particle  60  may also be used. 
     If desired, elongated members formed from glass or other stiffening material may be incorporated into polymer  50  in locally thinned region  44 . As shown in  FIG.  10   , for example, a series of parallel elongated members such as glass strips  70  or other members that extend parallel to bend axis  28  may serve as stiffening structures. Strips  70  may be incorporated into polymer  50  to help vertically stiffen surface  40  in locally thinned portion  44  of display cover layer  14 CG (e.g., to help prevent surface  40  from being too easily deformed inwardly when the portion of surface  40  that overlaps thinned portion  44  is contacted by a computer stylus or other external object that presses inwardly on surface  40 ). Although strips  70  provide enhanced vertical rigidity to surface  40  over portion  44 , the presence of strips  70  will not reduce the flexibility of display  14  with respect to bending about bend axis  28 , because strips  70  are free to move with respect to each other and with respect to thinned portion  44  of display cover layer  14 CG as display  14  is folded. 
     Polymer  50 , which fills the recess of thinned portion  44  of display cover layer  14 CG, may extend laterally to cover regions of inner surface  42  on non-thinned portions of display cover layer  14 CG (see, e.g., portion  50 ′, as described in connection with  FIG.  6   ). If desired, a separate polymer protective coating may be formed on inner surface  42  (see, e.g., coating layer  54  of  FIG.  5   ). As described in connection with layers  52  of  FIG.  4   , one or more optional layers may be provided on outer surface  40  such as layer  52  of  FIG.  10   . There may be any suitable number of parallel strips  70  in the recess of thinned portion  44 . There are three strips  70  in the example of  FIG.  10   . There may be fewer than three strips  70  or more than three strips  70 , if desired. Strips  70  may be formed from glass or other rigid transparent material (clear ceramic, sapphire or other crystalline material, etc.). Configurations in which strips  70  are glass strips and lie parallel to surfaces  40  and  42  when display  14  is in an unfolded planar state are sometimes described herein as an example. The presence of strips  70  helps ensure that surface  40  will not be too easily deformed inwardly when contacted by a stylus or other external object. The presence of elongated polymer-filled gaps between adjacent strips  70  (e.g., gaps that extend parallel to bend axis  28 ) helps to ensure that display  14  can exhibit sufficient flexibility to bend about axis  28  when device  10  is folded and unfolded. 
     In the example of  FIG.  11   , a display cover layer similar to that of  FIG.  10    has been constructed using a pair of laminated layers. In locally thinned portion  44 , display cover layer  14 CG exhibits enhanced local flexibility, because only a single thickness of display cover layer material (e.g., a single glass layer) is present (e.g., display cover layer  14 CG- 1  is present and display cover layer  14 CG- 2  is not present in portion  44 ). In portions  46 , display cover layer  14 CG includes both upper display cover layer  14 CG- 1  and lower display cover layer  14 CG- 2  (e.g., an additional glass layer). Lower display cover layer  14 CG- 2  is attached to upper display cover layer  14 CG- 1  by a layer of polymer such as polymer adhesive  72  (e.g., part of polymer  50  or a separate polymer layer). Polymer  50  may have portions  50 ′ that extend to form a protective inner surface cover layer on surface  42  or a separate protective polymer layer may be formed on surface  42 , as shown in  FIG.  5   . Layer  14 CG- 2  of  FIG.  11    has two halves (e.g., left and right halves separated by a gap that forms a recess in display cover layer  14 CG under thinned portion  44 ). The gap in layer  14 CG- 2  helps enhance the flexibility of layer  14 CG so that layer  14 CG can bend about bend axis  28 . Strips  70  and/or other stiffening structures may be embedded in polymer  50  in the gap formed between the left and right halves of layer  14 CG. 
     To help reduce cracks that might weaken strips  70 , strips  70  may be etched in a glass etchant (e.g., HF) and/or mechanically polished. This process and/or other processing techniques may be used to form glass strips such as strip  70  of  FIG.  12   , which has a cross-sectional profile with a rectangular shape having rounded corners  70 R. The presence of rounded corners  70 R or other curved surface profiles may help prevent chips and other damage in the event that adjacent strips  70  contact each other and may help to remove cracks that could lead to fracturing. 
     The thickness of display cover layer  14 CG in region  44  may be 30-200 microns, at least 10 microns, at least 20 microns, less than 500 microns, less than 300 microns, less than 200 microns, less than 100 microns, or other suitable thickness that is less than the thickness of display cover layer  14 CG in non-thinned regions. The thickness of glass strips  70  (which may be the same as the thickness of layer  14 CG- 2  in the configuration of  FIG.  11   ) may be 30-200 microns, at least 10 microns, at least 20 microns, less than 500 microns, less than 300 microns, less than 200 microns, less than 100 microns, or other suitable thickness. The thickness of display cover layer  14 CG in regions  46  may be 30-600 microns, 100-600 microns, 100-400 microns, at least 30 microns, at least 100 microns, at least 200 microns, less than 3000 microns, less than 1000 microns, less than 600 microns, less than 400 microns, or other suitable thickness. 
     Strips  70  may each have the same width or the widths of strips  70  may differ from each other. The width of each of strips  70  may be at least 10 microns, at least 100 microns, at least 500 microns, at least 1.5 mm, at least 3 mm, at least 6 mm, 1-10 mm, 1-3 mm, 0.5-2 mm, less than 10 mm, less than 7 mm, less than 4 mm, less than 2.5 mm, less than 1.5 mm, or other suitable width. The length of each strip  70  may span the entire width of device  10  (e.g., each strip  70  may have a length equal to the distance that bend axis  28  traverses across device  10  and display  14 ) or each of strips  70  may be divided into two or more segments along its length (e.g., a strip may have two halves or more segments arranged end-to-end that collectively span the width of display  14 ). Strips  70  may be formed from the same material (e.g., the same glass) as display cover layer  14 CG or may be formed from a material with an identical or similar refractive index. This may help match the refractive index values of strips  70  to the refractive index of display cover layer  14 CG (e.g., so that index of strips  70  differs from the index of layer  14 CG and from the index of polymer  50  by less than 0.15, by less than 0.1, or by less than 0.05, as examples). 
     To help enhance the rigidity of surface  40  over thinned portion  44 , polymer  50  of  FIGS.  10  and  11    may include glass beads or other stiffening particles in addition to stiffening structures such as strips  70  (e.g., the polymer-filled groove under portion  44  may contain both stiffening structures such as glass beads and stiffening structures such as glass strips). The stiffening particles may be particles such as particles  60  of  FIG.  7   . Such particles may have a single diameter or may have varying diameters (e.g., diameters that vary as shown by curves  64  and  66  of  FIG.  8    or that otherwise decrease as a function of increasing distance into polymer  50  away from outer surface  40 ). If desired, index-matching nanoparticles  62  may also be incorporated into polymer  50  to help match the refractive index of polymer  50  to that of strips  70  and display cover layer  14 CG (e.g., thinned portion  44 ). 
     Polymer  50  may be stiffened and/or index-matched to display cover layer  14 CG using an inhomogeneous mixture of embedded particles (particles of different sizes, shapes, and/or materials) or a homogenous mixture of embedded particles. Embedded particles (e.g., particles  60  and/or  62  and/or other particles in polymer  50 ) may be formed from materials having a refractive index that differs from that of polymer  50  (e.g., particles for index matching polymer  50  to cover layer  14 CG and optionally stiffening polymer  50 ) and/or from materials having a matched refractive index (e.g., particles used for stiffening polymer  50  but not used to change the refractive index of polymer  50 ). The embedded particles may be nanoparticles and/or larger particles having fixed characteristics throughout polymer  50  and/or having one or more characteristics that vary as a function of distance through the thickness of polymer  50 . 
     The embedded particles may, for example, have a mean size or other attribute (e.g., composition, shape, etc.) that varies as a function of position within polymer  50  (e.g., as a function of distance d) in a smooth and continuous (non-stepwise) fashion and/or in a stepwise fashion). Embedded particles may be formed from glass beads, other glass particles, and/or other dielectric (e.g., beads or other particles formed from silica, metal oxides such as zirconia particles, alumina particles, titania particles, etc.). The embedded particles may be spherical, plate-shaped (e.g., flakes), rod-shaped, and/or may have other suitable shapes. 
     In an illustrative configuration, the embedded particles are particles characterized by a mean diameter. The mean diameter of the particles may be 0.01 microns to 50 microns, 0.05 microns to 25 microns, 0.01 microns to 25 microns, 0.03 microns to 50 microns, at least 0.01 microns, at least 0.1 microns, at least 1 micron, less than 50 microns, less than 5 microns, less than 0.5 microns, etc. The mean diameter may be fixed throughout a homogenous mixture in polymer  50  and/or may have a value within these ranges or other suitable ranges that varies as a function of position within polymer  50  (e.g., as a function of distance d), etc. As an example, embedded dielectric particles in polymer  50  may be characterized by a mean diameter of 0.01 microns to 50 microns (or other suitable range) that is fixed through polymer  50  or that varies as a function of distance (e.g., distance d) through polymer  50  while serving to enhance resistance of the outer surface of display cover layer  14 CG over the locally thinned portion of the display cover layer to inward deformation and while allowing the display cover layer to bend about bend axis  28 . 
     As described above, one aspect of the present technology is the gathering and use of information such as information from input-output devices. The present disclosure contemplates that in some instances, data may be gathered that includes 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, 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 information that may include 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 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 merely illustrative and various modifications can be made to the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20211130
Publication Date: 20241008
Grant Date: 20241008
Priority Date: 20201218
Inventors: NGUYEN, Que Anh S.
ROGERS, MATTHEW S.
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F1/1652", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K5/0017", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10K77/111", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1652", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1641", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1637", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/0268", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K5/03", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04M1/0216", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K5/0017", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1652", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K5/03", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 82021935