PATENT DOCUMENT

Publication Number: US-9947882-B2
Application Number: US-201615211714-A
Country: US
Kind Code: B2

Title: Electronic devices with robust flexible displays

Abstract:
An electronic device may have a hinge that allows the device to be flexed about a bend axis. A display may span the bend axis. To protect display elements such as pixel circuitry from excessive mechanical stress, the display may include one or more structural protective layers. A structural layer may be incorporated into the display stack as a supportive backing behind the pixel circuitry and/or as a protective cover over the pixel circuitry. The structural layer may include rigid portions and flexible portions. The flexible portions may contain flexible material that separates and adjoins adjacent rigid structures or that fills grooves between adjacent rigid portions. The rigid portions may be formed from thin sheets of glass or other transparent materials. The flexible material in the structural layer may be an elastomeric material having a refractive index that matches that of the glass sheets in the structural layer.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a housing that bends about a bend axis; and 
 a display in the housing that bends about the bend axis, wherein the display comprises a protective layer having a rigid portion formed from a first material and a flexible portion formed from a second material that is different than the first material. 
 
     
     
       2. The electronic device defined in  claim 1  wherein the first material comprises glass. 
     
     
       3. The electronic device defined in  claim 1  wherein the second material comprises polymer. 
     
     
       4. The electronic device defined in  claim 1  wherein the display comprises an array of pixels that emit light through an upper surface of the display and wherein the protective layer is interposed between the upper surface and the array of pixels. 
     
     
       5. The electronic device defined in  claim 1  wherein the display comprises an array of pixels that emit light through an upper surface of the display and wherein the array of pixels is interposed between the upper surface and the protective layer. 
     
     
       6. The electronic device defined in  claim 5  further comprising an additional protective layer interposed between the upper surface of the display and the array of pixels, wherein the additional protective layer has a rigid portion and a flexible portion. 
     
     
       7. The electronic device defined in  claim 6  wherein the flexible portion of the protective layer and the flexible portion of the additional protective layer are aligned with the bend axis. 
     
     
       8. The electronic device defined in  claim 1  wherein the first material comprises glass having a first index of refraction and the second material comprises polymer having a second index of refraction that matches the first index of refraction. 
     
     
       9. The electronic device defined in  claim 1  wherein the protective layer comprises an additional rigid portion and wherein the flexible portion is interposed between the rigid portion and the additional rigid portion. 
     
     
       10. The electronic device defined in  claim 9  wherein the rigid portion comprises a first glass structure, wherein the additional rigid portion comprises a second glass structure, and wherein the flexible portion comprises a strip of polymer that separates the first glass structure from the second glass structure. 
     
     
       11. The electronic device defined in  claim 1  wherein the protective layer comprises a layer of glass and wherein the flexible portion of the protective layer comprises at least one recess in the layer of glass. 
     
     
       12. A flexible display that bends about a bend axis, comprising:
 a touch-sensitive layer; 
 an array of pixels formed on a polymer substrate; and 
 a support layer comprising a flexible region interposed between first and second rigid regions, wherein the array of pixels is interposed between the touch-sensitive layer and the support layer. 
 
     
     
       13. The flexible display defined in  claim 12  wherein the flexible region comprises polymer. 
     
     
       14. The flexible display defined in  claim 13  wherein the first and second rigid regions comprise glass. 
     
     
       15. The flexible display defined in  claim 14  wherein the glass has a first index of refraction and the polymer has a second index of refraction that matches the first index of refraction. 
     
     
       16. The flexible display defined in  claim 12  wherein the array of pixels overlaps the flexible region of the support layer. 
     
     
       17. A flexible display that bends along a bend axis, comprising:
 a first structural layer having first and second glass sheets joined by a first flexible material; 
 a second structural layer having third and fourth glass sheets joined by a second flexible material; and 
 an array of pixels interposed between the first and second structural layers. 
 
     
     
       18. The flexible display defined in  claim 17  wherein the first and second flexible materials are aligned with the bend axis. 
     
     
       19. The flexible display defined in  claim 17  wherein the first and second glass sheets have a first index of refraction and the first flexible material has a second index of refraction that matches the first index of refraction. 
     
     
       20. The flexible display defined in  claim 17  wherein the array of pixels comprises organic light-emitting diode pixels formed on a polymer substrate.

Description:
This application claims the benefit of provisional patent application No. 62/232,653, filed on Sep. 25, 2015, which is hereby incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     This relates generally to electronic devices, and, more particularly, to electronic devices with displays. 
     Electronic devices often include displays for presenting image to a user. Displays are typically formed from rigid planar substrates. Although satisfactory in many situations, rigid displays such as these may be difficult to integrate into certain devices, such as devices with bendable housings. 
     It would therefore be desirable to be able to provide improved displays for electronic devices. 
     SUMMARY 
     An electronic device may have a display. The electronic device may have a hinge that allows the device to be flexed about a bend axis. The display may overlap the bend axis. 
     To protect display elements such as pixel circuitry from excessive mechanical stress, the display may include one or more structural protective layers. A structural layer may be incorporated into the display stack as a supportive backing behind the pixel circuitry and/or as a protective cover over the pixel circuitry. 
     The structural layer may include rigid portions and flexible portions. The flexible portions may contain flexible material that separates and adjoins adjacent rigid structures or that fills grooves between adjacent rigid portions. 
     The rigid structures in the structural layer may be formed from thin sheets of glass or other transparent materials. The flexible material in the structural layer may be an elastomeric material having a refractive index that matches that of the rigid structures. 
     The flexible material may form flexible joints between adjacent rigid structures to isolate and absorb impact energy so that it does not travel to adjacent rigid structures or other components in the electronic device. The flexible portions in the structural layer may facilitate bending of the display about the bend axis. The flexible portions of the structural layer may be aligned with the bend axis of the display and/or may be located in regions of the display that do not flex or bend. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative electronic device having a display in accordance with an embodiment. 
         FIG. 2  is a schematic diagram of an illustrative electronic device having a display in accordance with an embodiment. 
         FIGS. 3 and 4  are cross-sectional side views of electronic devices with flexible displays in accordance with an embodiment. 
         FIG. 5  is a cross-sectional side view of an illustrative structural layer having rigid and flexible portions in accordance with an embodiment. 
         FIG. 6  is a cross-sectional side view of an illustrative display having display circuitry interposed between first and second structural layers in accordance with an embodiment. 
         FIG. 7  is a cross-sectional side view of an illustrative display having display circuitry interposed between first and second structural layers and including an additional protective film in accordance with an embodiment. 
         FIG. 8  is a cross-sectional side view of an illustrative display having display circuitry interposed between a first structural layer and a second structural layer having multiple rigid portions and flexible portions in accordance with an embodiment. 
         FIG. 9  is a cross-sectional side view of an illustrative structural layer having rigid portions and flexible portions in which the flexible portions are formed from thinned regions of a rigid layer in accordance with an embodiment. 
         FIGS. 10, 11, 12, 13, 14, 15, 16, and 17  are top views of illustrative patterns for rigid portions and flexible portions of a structural layer for a display in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     An illustrative electronic device of the type that may be provided with a flexible display is shown in  FIG. 1 . Electronic device  10  may be a computing device such as a laptop computer, a computer monitor containing an embedded computer, a tablet computer, a cellular telephone, a media player, or other handheld or portable electronic device, a smaller device such as a wrist-watch device, a pendant device, a wearable or miniature device of other types, a computer display that does not contain an embedded computer, a computer display that includes an embedded computer, a gaming device, a navigation device, an embedded system such as a system in which electronic equipment with a display is mounted in a kiosk or automobile, equipment that implements the functionality of two or more of these devices, or other electronic equipment. In the illustrative configuration of  FIG. 1 , device  10  is a portable device such as a cellular telephone, media player, tablet computer, watch or other wrist device, or other portable computing device. Other configurations may be used for device  10  if desired. The example of  FIG. 1  is merely illustrative. 
     In the example of  FIG. 1 , device  10  includes a display such as display  14  mounted in housing  12 . Housing  12 , which may sometimes be referred to as an enclosure or case, may be formed of plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or a combination of any two or more of these materials. Housing  12  may be formed using a unibody configuration in which some or all of housing  12  is machined or molded as a single structure or may be formed using multiple structures (e.g., an internal frame structure, one or more structures that form exterior housing surfaces, etc.). Housing  12  may have hinge structures such as hinge  20  to allow device  10  to bend about bend axis  22 . 
     Display  14  may be a touch screen display that incorporates a layer of conductive capacitive touch sensor electrodes or other touch sensor components (e.g., resistive touch sensor components, acoustic touch sensor components, force-based touch sensor components, light-based touch sensor components, etc.) or may be a display that is not touch-sensitive. Capacitive touch screen electrodes may be formed from an array of indium tin oxide pads or other transparent conductive structures. A touch sensor may be formed using electrodes or other structures on a display layer that contains a pixel array or on a separate touch panel layer that is attached to the pixel array (e.g., using adhesive). 
     Display  14  may include pixels formed from liquid crystal display (LCD) components, electrophoretic pixels, microelectromechanical (MEMS) shutter pixels, electrowetting pixels, micro-light-emitting diodes (small crystalline semiconductor die), organic light-emitting diodes (e.g., a thin-film organic light-emitting diode display), quantum dot light-emitting diodes, or pixels based on other display technologies. Configurations in which display  14  is a light-emitting diode display such as an organic light-emitting diode display may sometimes be described herein as an example. 
     Display  14  may include multiple layers. The layers of display  14  may include one or more layers such as an outer protective layer with a polarizer, a touch panel layer, a thin-film transistor layer containing thin-film transistor circuitry and associated organic light-emitting diodes or other pixels on a polymer substrate, and a supporting backing layer. More display layers or fewer display layers and/or different types of layers may be included in display  14 , if desired. A display cover layer or other layer may form the outermost surface of the display. Display layers such these (e.g., display cover layers) may be formed from glass, plastic, and/or other transparent display cover layer structures and may have a flexible center portion aligned with the bend axis of device  10 . 
     Display layers may be formed from plastic (polymer), glass, metal, or other suitable materials. When constructed from sufficiently thin layers of material (e.g., 20 microns or less, 30 microns or less, 50 microns or less, 1-40 microns, or other suitable thicknesses), the display layers may be bent without experiencing potentially damaging plastic deformation or cracking. In a display configuration with multiple thin layers such as these, display  14  may therefore be bent back and forth about bend axis  22  without damaging display  14 . 
     Display  14  may include flexible regions such as region  14 B that allow display  14  to be bent, curved, or folded and structural regions such as regions  14 A that provide structure and impact protection for display  14 . In the example of  FIG. 1 , the center portion of display  14  (and, if desired, some or all of the remaining portions of display  14 ) may be flexible to allow display  14  to be bent along bend axis  22  of device  10 . 
     The center of the display panel may be formed using flexible structures. In areas  14 A, display  14  may be flexible or may be rigid (e.g., the display panel structures in these areas may be rigid and/or the display cover layer structures in these areas may be rigid). In the example of  FIG. 1 , flexible area  14 B forms a strip that lies between structural areas  14 A. To ensure that flexible area  14 B is sufficiently flexible to allow device  10  to bend about axis  22 , display layers such as a display cover layer for display  14  may be provided with flexible structures in area  14 B. Underlying display layers in a display panel (e.g., an internal structural layer, a polymer substrate, metal traces, and other conducting and dielectric layers in an organic light-emitting diode panel) may also be provided with structures that are flexible and can be bent without damage in regions  14 B. 
     The example of  FIG. 1  in which display  14  bends about a bend axis at the center of the display that extends across the width of the display is merely illustrative. If desired, display  14  may bend about an axis that is perpendicular to axis  22  of  FIG. 1  (i.e., an axis that extends along the length of display  14 ) and/or an axis that is not at the center of the display. Configurations in which display  14  bends about multiple axes (e.g., multiple parallel or non-parallel axes) may also be used. Arrangements in which display  14  bends about axis  22  are sometimes described herein as an illustrative example. 
     A schematic diagram of an illustrative electronic device such as device  10  of  FIG. 1  is shown in  FIG. 2 . As shown in  FIG. 2 , electronic device  10  may have control circuitry  16 . Control circuitry  16  may include storage and processing circuitry for supporting the operation of device  10 . The storage and processing circuitry may include storage such as hard disk drive storage, nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory configured to form a solid state drive), volatile memory (e.g., static or dynamic random-access-memory), etc. Processing circuitry in control circuitry  16  may be used to control the operation of device  10 . The processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, baseband processors, power management units, audio chips, application specific integrated circuits, etc. 
     Input-output circuitry in device  10  such as input-output devices  18  may be used to allow data to be supplied to device  10  and to allow data to be provided from device  10  to external devices. Input-output devices  18  may include buttons, joysticks, scrolling wheels, touch pads, key pads, keyboards, microphones, speakers, tone generators, vibrators, cameras, sensors, light-emitting diodes and other status indicators, data ports, etc. A user can control the operation of device  10  by supplying commands through input-output devices  18  and may receive status information and other output from device  10  using the output resources of input-output devices  18 . Input-output devices  18  may include a display such as display  14  of  FIG. 1 . 
     Control circuitry  16  may be used to run software on device  10  such as operating system code and applications. During operation of device  10 , the software running on control circuitry  16  may display images on display  14  (e.g., video, still images such as text, alphanumeric labels, photographs, icons, other graphics, etc.) using an array of pixels in display  14 . 
     As shown in  FIG. 3 , device  10  may be folded (bent by 180° or other suitable amount) about bend axis  22  so that display  14  is visible from the outside of device  10  in its folded state.  FIG. 4  shows how device  10  may be folded about bend axis  22  so that display  14  is protected within the interior of device  10 . Device  10  may have hinges that allow outward bending of the type shown in  FIG. 3 , that allow inward bending of the type shown in  FIG. 4 , or that allow bending of both the type shown in  FIG. 3  and the type shown in  FIG. 4 . Configurations in which device  10  is flexed by different amounts (e.g., more than 180° or less than 180°) may also be used. 
     Display  14  may have an outermost layer formed from clear glass, transparent plastic, sapphire, or other transparent materials that serve as a protective layer for thin-film transistor circuitry and other display structures. The outer display layer may sometimes be referred to as a display cover layer. In some configurations for display  14 , the outermost layer of the display may serve both as a protective layer (display cover layer) and as a substrate for display structures (touch sensors electrodes, color filter elements, thin-film transistors, etc.). In other configurations, the display cover layer is free of circuitry and serves solely as a protective layer for underlying display structures (e.g., one or more underlying display panels). 
     To provide display  14  with increased robustness, one or more structural protective layers may be incorporated into the layers that form display  14 . The protective layer may have one or more rigid portions and one or more flexible portions. The rigid portions of the protective layer may increase the stiffness of display  14  in those regions while isolating impact energy, while the flexible portions of the protective layer may allow display  14  to remain flexible and bendable. 
     As shown in  FIG. 5 , a protective layer for display  14  (i.e., protective layer  24 ) may have rigid portions such as rigid portions  24 A and flexible portions such as flexible portion  24 B. Rigid portions  24 A may, for example, be rigid planar layers. Configurations in which portions  24 A have non-planar shapes and/or are formed from flexible structures may also be used. Between rigid planar portions  24 A of protective layer  24 , protective layer  24  may have flexible portion  24 B. Portion  24 B may bend about bend axis  22  to allow display  14  to bend as housing  12  is bent about hinge  20 . 
     In the example of  FIG. 5 , flexible portion  24 B of protective layer  24  aligns with flexible region  14 B of display  14  (e.g., the region of display  14  that bends about bend axis  22 ). This is, however, merely illustrative. If desired, protective layer  24  may include flexible regions  24 B in rigid areas  14 A of display  14  (e.g., in areas of display  14  that do not bend, that are prevented from being bent, or that are otherwise less flexible than regions  14 B). 
       FIG. 6  is a cross-sectional side view of display  14  in an illustrative configuration in which protective layers of the type shown in  FIG. 5  are incorporated into display  14 . As shown in  FIG. 6 , display  14  may include display layers  30  and additional layers  32 . Display layers  30  may include substrate layer  30 - 1 , thin-film transistor layer  30 - 2 , pixel structures  30 - 3 , and moisture barrier layer  30 - 4 . Substrate  30 - 1  may be a flexible polymer substrate formed from a flexible sheet of polyimide or other suitable flexible material. Thin-film transistors  30 - 2  may be used to control display pixels  30 - 3 . Pixel structures  30 - 3  may include organic light-emitting diode display pixels or other suitable display pixels. Moisture barrier layer  30 - 4  may be a thin-film encapsulation layer formed from silicon nitride or other inorganic material. Display layers  30  may have a total thickness T 5  of about 20 microns, 15-30 microns, 20-50 microns, more than 50 microns, or less than 50 microns. 
     Top layers  32  may include layers such as touch-sensitive layer  32 - 1 , polarizer layer  32 - 2 , and functional layers  32 - 3 . Touch-sensitive layer  32 - 1  may include touch sensor circuitry such as capacitive touch sensor electrodes (e.g., formed from indium tin oxide, thin metal, or other transparent conductive material) or other suitable touch-sensitive circuitry. Polarizer layer  32 - 2  may, for example, be a circular polarizer that reduces reflections from display  14 . Functional layers  32 - 3  may include a hard outer layer (e.g., formed from one or more inorganic layers such as silicon nitride, silicon oxide, etc.) that provides a scratch resistant surface of the type that is sometimes referred to as a hardcoat. Other layers that may be included in functional layers  32 - 3  include an anti-smudge layer, an antireflection layer, an antistatic layer, layers that perform the functions of two or more of these layers, etc. Top layers  32  may have a total thickness T 1  of about 100 microns, 70-100 microns, 80-90 microns, 90-120 microns, greater than 100 microns, or less than 100 microns. 
     The layers shown in  FIG. 6  are merely illustrative. If desired, display  14  may have a fewer number of layers, a greater number of layers, a different order of layers, or other suitable configuration. 
     Display layers  30  and additional layers  32  may be formed using flexible materials to allow display  14  to be bent, curved, or folded (e.g., folded about bend axis  22 ). For example, polymer materials such as polyimide may be used to form at least some of display layers  30  and additional layers  32 . Other elements in display  14  such as thin-film encapsulation layer  30 - 4  and thin-film transistor circuitry  30 - 2  may be formed from inorganic brittle layers. The use of polymer materials enables bending of display  14 , but care must be taken to ensure that deformation of display  14  does not damage any of the layers within display  14 . For example, if care is not taken, excessive deformation of polymer layers can lead to an undesired waviness in the display or can lead to cracking in the thin-film transistor layer, which may in turn lead to “dead” pixels. 
     To increase the robustness of flexible display  14 , protective layers of the type shown in  FIG. 5  may be incorporated into display  14 . In the example of  FIG. 6 , first protective layer  24 - 1  is formed on one side of display layers  30  and second protective layer  24 - 2  is formed on an opposing side of display layers  30 . Protective layers  24 - 1  and  24 - 2  may provide the other layers in display  14  with structural support, may help protect display  14  from damage (e.g., damage from impact from a hard object, damage from inadvertent twisting, etc.), may help isolate impact energy, may help ensure that display  14  is planar, and may otherwise help strengthen and support display  14 . Lower protective layer  24 - 1  may have a thickness T 7  of about 100 microns, 70-100 microns, 80-90 microns, 90-120 microns, 50-80 microns, greater than 100 microns, or less than 100 microns. Upper protective layer  24 - 2  may have a thickness T 3  of about 50-100 microns, 50-60 microns, 40-80 microns, 80-120 microns, more than 80 microns, or less than 80 microns. 
     Layers of adhesive may be used to attached the layers of display  14  together. For example, adhesive layer  34  may attach additional layers  32  to upper protective layer  24 - 2 , adhesive layer  36  may attach upper protective layer  24 - 2  to display layers  30 , and adhesive layer  48  may attach display layers  30  to lower protective layer  24 - 1 . Adhesive layers  34  and  36  may be optically clear adhesive to allow light from display layers  30  to exit upper surface  14 U of display  14 , while adhesive layer  48  need not be transparent (e.g., a pressure sensitive adhesive or other suitable adhesive may be used to form adhesive layer  48 ). The respective thicknesses T 2 , T 4 , and T 6  of adhesive layers  34 ,  36 , and  48  may each be about 15-20 microns, 10-30 microns, 30-60 microns, 60-100 microns, 80-120 microns, 100-150 microns, greater than 150 microns, or less than 150 microns. 
     Sandwiching display layers  30  between protective layers  24 - 1  and  24 - 2  may protect display layers  30  from damage when a hard object impacts display  14 . Protective layer  24 - 1  protect display layers  30  from impacts on lower surface  14 L of display  14 , while protective layer  24 - 2  protects display layers  30  from impacts on upper surface  14 U of display  14  (e.g., the surface of display  14  through which light from display layers  30  exits display  14 ). 
     Protective layers  24 - 1  and  24 - 2  may have rigid portions  24 A and flexible portions  24 B. Rigid portions  24 A of protective layers  24 - 1  and  24 - 2  may be formed from rigid structures  40 . Rigid structures  40  may be a material such as glass, metal, plastic, or other suitable material. In one illustrative arrangement, rigid structures  40 - 2  in upper protective layer  24 - 2  may be transparent to allow light from display layers  30  to exit upper surface  14 L of display  14  and rigid structures  40 - 1  in protective layer  24 - 1  may be opaque. In another illustrative arrangement, both rigid structures  40 - 1  and  40 - 2  may be transparent. For example, rigid structures  40 - 1  and  40 - 2  may be formed from sheets of strengthened glass. If desired, rigid structures  40  may optionally be used as substrates for additional circuitry  80  such as touch sensor circuitry, force sensor circuitry, or other suitable circuitry in display  14 . 
     Rigid structures  40  in protective layers  24 - 1  and  24 - 2  may be connected by flexible material  38 . Flexible material  38  may be a polymer or other flexible substance. Flexible material  38  may be, for example, a clear elastomeric polymer such as silicone or optically clear adhesive to permit viewing of display layers  30  or may be formed from an opaque polymer. Other filler materials may be used, if desired. In configurations in which material  38  is transparent, material  38  may have an index of refraction that matches the index of refraction of rigid structures  40 . For example, rigid structures  40 - 2  of upper protective layer  24 - 2  may have an index of refraction of 1.5 and flexible material  38 - 2  may be formed from a polymer with a matched index of refraction of 1.5 (or 1.4-1.6 or other suitable value close to 1.5). 
     Material  38  (sometimes referred to as flexible joints  38 ) may be used to adjoin neighboring rigid structures  40  and to isolate one rigid structure  40  from surrounding rigid structures  40 . The presence of flexible material  38  between rigid structures  40  may help isolate and absorb impact energy that may result from an external object striking display  14 . The flexible material  38  may also enable folding flexibility in regions  24 B of protective layer  24 . Thus, protective layers  24  may not only be used to protect underlying display layers  30 , but protective layers  24  may also be used to prevent impact energy from transferring from rigid structures  40  to other structures in housing  12  of device  10 . 
     Protective layer  24 - 1  may have the same construction and design as protective layer  24 - 2  or the two protective layers may have different features. For example, the thickness T 7  of lower protective layer  24 - 1  may be different than the thickness T 3  of upper protective layer  24 - 2  to adjust the neutral plane position in display  14  such that it intersects with display layers  30  (e.g., such that thin-film transistor layer  30 - 2  and pixel structures  30 - 3  are located in the neutral plane of display  14 ). The properties of flexible joints  38  may also be adjusted to achieve a desired bending ability. For example, flexible joint  38 - 1  of lower protective layer  24 - 1  may be larger or smaller than flexible joint  38 - 2 , may be more or less flexible than flexible joint  38 - 2 , may relax more quickly or more slowly than flexible joint  38 - 2  (e.g., may have a different restoring force than that of material  38 - 2 ), etc. Flexible joints  38  may be patterned with holes or may have three-dimensional structuring. Functional components such as sensors, optical structures, mechanical elements, or other components may be embedded into material  38 . 
     Each protective layer  24  may include any suitable number of rigid structures  40  and any suitable number of flexible joints  38 . Rigid structures  40  may be completely or partially isolated from one another by flexible joints  38 . Rigid structures  40  may be islands of any suitable shape (e.g., rectangular, circular, oval, etc.). Rigid structures  40  may have grooves, curved surfaces, or other surface features to facilitate bending. Rigid structures  40  and flexible joints  38  may have engagement features that help bind structures  40  to joints  38 . For example, rigid structures  40  may have protrusions that extend into openings in flexible joints  38  and/or rigid structures  40  may have openings that receive corresponding portions of material  38 . 
     The example of  FIG. 6  in which two protective layers  24  are incorporated into display  14  is merely illustrative. If desired, only one protective layer may be incorporated into display  14  or display  14  may have more than two protective layers. Protective layers  24  may be formed in any suitable location in the stack of layers that form display  14 . The configuration of  FIG. 6  is merely illustrative. 
     If desired, an additional protective layer may be formed under lower protective layer  24 - 1  to provide additional protection to display  14 . As shown in  FIG. 7 , for example, protective film  42  may be formed on lower surface  14 L of display  14  to protect layer  24 - 1  from impacts on surface  14 L. Film  42  may be an elastomeric polymer such as silicone or other suitable polymer. 
     In configurations where structures  40  in protective layers  24  are formed from thin glass sheets and/or where structures  40  include circuitry  80  (e.g., glass-based sensors or other sensitive structures), elastomeric film  42  may help absorb impacts on lower surface  14 L and avoid damage to structures  40 . 
       FIG. 8  shows an illustrative example in which lower protective layer  24 - 1  has multiple strips or islands of rigid structures  40 - 1  separated from and adjoined to one another by flexible joints  38 - 1 . Protective layer  24 - 1  may, for example, include two, three, four, ten, less than ten, or more than ten individual rigid structures  40  joined together by flexible joints  38 . The use of multiple smaller rigid structures  40 - 1  separated by flexible material  38 - 1  isolates mechanical stresses to smaller areas of display  14  while also allowing for increased flexibility in protective layer  24 - 1 . 
     In the example of  FIG. 8 , lower protective layer  24 - 1  has more rigid portions  40 - 1  and flexible joints  38 - 1  than upper protective layer  24 - 2 . This is merely illustrative. If desired, upper protective layer  24 - 2  may have more rigid portions  40 - 2  and flexible joints  38 - 2  than layer  24 - 1  or may have the same number of rigid portions  40 - 2  and flexible joints  38 - 2 . 
     The examples of  FIGS. 6, 7, and 8  in which flexible regions  24 B of protective layer  24  are formed using flexible material that separates adjacent rigid structures is merely illustrative. If desired, flexible regions  24 B of protective layer  24  may be formed by selectively removing portions of a rigid layer to form recessed areas in flexible regions  24 B. By creating one or more recesses in region  24 B (relative to portions  24 A), the flexibility of protective layer  24  in region  24 B may be increased. 
     In the illustrative configuration of  FIG. 9 , protective layer  24  has been provided with grooves  44  in regions  24 B. Grooves  44  may have depths D of about 50 microns (or more than 10 microns, more than 20 microns, 30-80 microns, 5-200 microns, less than 250 microns, less than 100 microns, less than 75 microns, less than 50 microns, or other suitable value). Grooves  44  may have widths W of 1-200 microns, more than 5 microns, more than 40 microns, more than 200 microns, more than 500 microns, less than 400 microns, less than 1 mm, less than 100 microns, 0.5-5 mm, or other suitable widths). 
     In general, any suitable dimensions may be used for the structures of protective layer  24 . The use of parallel grooves with semicircular cross-sectional shapes that run across the width of display  14  (e.g., parallel to bend axis  22  of  FIG. 1 ) is merely illustrative. 
     Grooves  44  may have any suitable shape. As shown in the cross-sectional side view of grooves  44  of  FIG. 9 , grooves  44  may have a semicircular shape or other shape with curved sidewall surfaces. In other arrangements, grooves  44  may have trapezoidal shapes, rectangular shapes, rectangular shapes with curved corners, or other cross-sectional shapes. The illustrative groove profile of  FIG. 9  is merely illustrative. 
     Flexible material  38  may fill grooves  44  or, if desired, grooves  44  may be filled with air and flexible material  38  may be excluded. The thinned regions of rigid structure  40  in regions  24 B may allow increased flexibility in those regions while rigid structure  40  maintains the ability to protect underlying display layers  30  from impact stresses. Flexible material  38  may help support portion  24 B of protective layer  24  to prevent cracking. 
       FIGS. 10-17  show illustrative top views of protective layer  24  with different patterns of rigid regions  24 A and flexible regions  24 B. In these examples, rigid regions  24 A may be formed from one or more rigid structures  40 . Flexible regions  24 B may be formed using flexible material  38  that separates and adjoins adjacent rigid structures  40  (as shown in the examples of  FIGS. 6, 7, and 8 ) or may be formed using recesses, grooves, or cut-out portions of rigid structure  40  which may or may not be filled with flexible material  38  (e.g., as shown in the example of  FIG. 9 ). 
     In the example of  FIG. 10 , protective layer  24  comprises one flexible region  24 B interposed between first and second rigid regions  24 A. Flexible region  24 B may be a strip that extends across the width of display  14  parallel to and aligned with bend axis  22 . Aligning flexible region  24 B with bend axis  22  may facilitate bending of display  14  about axis  22 . However, if desired, flexible region  24 B of protective layer  24  may be offset relative to bend axis  22  and/or may be perpendicular to bend axis  22 . 
     In the example of  FIG. 11 , protective layer  24  includes multiple flexible regions  24 B alternating with multiple rigid regions  24 A. Flexible regions  24 B and rigid regions  24 A are strips that extend across the width of display  14  parallel to bend axis  22 . One or more of flexible regions  24 B may align with (e.g., overlap) bend axis  22  to facilitate bending of display  14  about axis  22 . 
     In the example of  FIG. 12 , protective layer  24  includes flexible regions  24 B that extend both across the width of display  14  (e.g., parallel to bend axis  22 ) and across the length of display  14  (e.g., perpendicular to bend axis  22 ). This causes some of rigid regions  24 A to be completely surrounded by flexible regions  24 B. The rectangular shape that the islands of rigid structures  40  have in  FIG. 12  is merely illustrative. Rigid structures  40  may have round shapes or other suitable shapes.  FIG. 13  shows how flexible regions  24 B may be formed in a hexagonal matrix separating hexagonal islands formed by rigid regions  24 A. 
     As shown in  FIG. 14 , flexible regions  24 B need not be straight. In the  FIG. 14  example, rigid regions  24 A and flexible regions  24 B each follow a meandering path that extends across the width of display  14 .  FIG. 15  shows how flexible regions  24 B of protective layer  24  may have pseudorandom patterns to help prevent optical interference effects from creating visible artifacts on display  14 . In the example of  FIG. 16 , flexible regions  24 B have an elongated shape that extends parallel axis  22  and have interlocking features such as protrusions and recesses that extend perpendicular to axis  22 . 
     It may be desirable for display  14  to deform along more than one dimension. For example, it may be desirable for display  14  to flex into a shape with compound curves, a dome shape, etc.  FIG. 17  is a diagram of protective layer  24  in an illustrative configuration in which flexible regions  24 B accommodate deformation along multiple axes. In particular, rigid regions  24 A and flexible regions  24 B form concentric rings that allow protective layer  24  to deform into the shape of a dome. Other patterns of rigid regions  24 A and flexible regions  24 B may be provided in display layers such as protective layer  24  or other layers of material in display  14  and/or housing  12  to enhance flexibility about bend axis  22 , if desired. 
     The foregoing is merely illustrative and various modifications can be made by those skilled in the art without departing from the scope and spirit of the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20160715
Publication Date: 20180417
Grant Date: 20180417
Priority Date: 20150925
Inventors: ZHANG, ZHEN
ZHANG, YIFAN
DRZAIC, PAUL S.
KELLEY, PAUL C.
LANDRY, JAMES P.
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F1/1652", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L51/5253", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L51/5275", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0412", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1616", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04102", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L51/0097", "inventive": true, "first": true, "tree": "[]"}, {"code": "H10K77/111", "inventive": true, "first": true, "tree": "[]"}, {"code": "H10K50/858", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10K50/844", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04102", "inventive": false, "first": false, "tree": "[]"}, {"code": "Y02E10/549", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1652", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1652", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1616", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1616", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0412", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10K59/873", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10K59/879", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 56550426