PATENT DOCUMENT

Publication Number: US-11500228-B1
Application Number: US-202117156139-A
Country: US
Kind Code: B1

Title: Electronic devices with sheet-packed coherent fiber bundles

Abstract:
An electronic device may have a display, a display cover layer, and a sheet-packed coherent fiber bundle. The coherent fiber bundle may have an input surface that receives an image from the display and a corresponding output surface to which the image is transported. The coherent fiber bundle may be placed between the display and the display cover layer and mounted to a housing. The coherent fiber bundle may have fiber cores with bends that help conceal the housing from view and make the display appear borderless. The coherent fiber bundle has filaments formed from elongated strands of binder in which multiple fiber cores are embedded. Sheets of filaments are stacked and fused together to form the coherent fiber bundle. By aligning and fusing the sheets with respect to each other the filaments are packed with a desired density and uniformity.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a display configured to produce an image; and 
 a sheet-packed coherent fiber bundle overlapping the display, wherein the sheet-packed coherent fiber bundle is configured to receive the image at an input surface and to transport the received image to an output surface, wherein the sheet-packed coherent fiber bundle comprises fused filaments each of which has multiple fiber cores. 
 
     
     
       2. The electronic device defined in  claim 1  wherein the sheet-packed coherent fiber bundle has fused sheets of filaments. 
     
     
       3. The electronic device defined in  claim 2  wherein each sheet of filaments includes multiple filaments having respective filament centers and wherein the filament centers of alternating sheets in the sheet-packed coherent fiber bundle are laterally offset with respect to each other. 
     
     
       4. The electronic device defined in  claim 3  wherein the filament centers of the filaments of odd sheets are laterally offset by half of a filament-center-to-filament-center spacing of the filaments of even sheets. 
     
     
       5. The electronic device defined in  claim 4  wherein each filament has multiple fiber cores. 
     
     
       6. The electronic device defined in  claim 5  wherein the fiber cores of each filament are embedded directly in binder material without intervening coating material. 
     
     
       7. The electronic device defined in  claim 5  wherein each fiber core is surrounded by at least one coating layer and wherein the fiber cores with the coating layers are embedded in binder material. 
     
     
       8. The electronic device defined in  claim 1  further comprising:
 a housing in which the display is mounted; and 
 electrical components between the housing and the display, wherein the sheet-packed coherent fiber bundle is configured to visually hide the housing so that the display appears borderless. 
 
     
     
       9. The electronic device defined in  claim 1  wherein the fiber cores include fiber cores with multiple bends. 
     
     
       10. An electronic device, comprising:
 a display configured to produce an image; and 
 a stack of fused filament sheets forming a coherent fiber bundle that overlaps the display, wherein the filament sheets comprise filaments and wherein each filament comprises an elongated strand of binder that contains multiple fiber cores. 
 
     
     
       11. The electronic device defined in  claim 10  wherein the fiber cores include fiber cores that have bends. 
     
     
       12. The electronic device defined in  claim 11  wherein the coherent fiber bundle is configured to receive the image at an input surface and to transport the received image to an output surface. 
     
     
       13. The electronic device defined in  claim 10  wherein the filaments of each filament sheet have respective filament centers, wherein first filament sheets alternate with second filament sheets in the stack of filament sheets, and wherein the filament centers of the first filament sheets are offset with respect to the filament centers of the second filament sheets. 
     
     
       14. The electronic device defined in  claim 13  wherein the fiber cores include fiber cores that have bends. 
     
     
       15. The electronic device defined in  claim 14  wherein the filament centers of the first sheets in the coherent fiber bundle are laterally offset with respect to the filament centers of the second sheets in the coherent fiber bundle by a distance equal to half of a filament-center-to-filament-center spacing in the first sheets. 
     
     
       16. The electronic device defined in  claim 15  wherein the filament centers of the first sheets in the coherent fiber bundle are laterally aligned with respect to each other. 
     
     
       17. An electronic device, comprising:
 a display configured to produce an image; 
 a transparent display cover layer; and 
 a sheet-packed coherent fiber bundle between the display and the transparent display cover layer, wherein the sheet-packed coherent fiber bundle is configured to receive the image at an input surface and to transport the received image to an output surface and wherein the sheet-packed coherent fiber bundle has a plurality of fused filament sheets, each filament sheet having multiple fused filaments that include fiber cores. 
 
     
     
       18. The electronic device defined in  claim 17 , wherein each filament comprises a plurality of the fiber cores. 
     
     
       19. The electronic device defined in  claim 18  wherein the fiber cores include fiber cores with bends.

Description:
This application claims the benefit of provisional patent application No. 62/990,375, filed Mar. 16, 2020, which is hereby incorporated by reference herein in its entirety. 
    
    
     FIELD 
     This relates generally to electronic devices, and, more particularly, to coherent fiber bundles for electronic devices with displays. 
     BACKGROUND 
     Electronic devices may have displays. Displays have arrays of pixels for displaying images for a user. To protect sensitive display structures from damage, displays may be provided with display cover layers. Display cover layers may be formed from glass, crystalline materials such as sapphire, or polymer. 
     SUMMARY 
     An electronic device may have a display, a display cover layer, and an image transport layer formed from a sheet-packed coherent fiber bundle. The coherent fiber bundle may have an input surface that receives an image from the display and a corresponding output surface to which the image is transported. The coherent fiber bundle may be placed between the display and the display cover layer or the display cover layer may be omitted so that the coherent fiber bundle forms an exterior surface of the electronic device. 
     In an illustrative configuration, the coherent fiber bundle, the display cover layer, and the display are mounted to a housing having a rear housing wall. Electronic components may be mounted in an interior portion of the electronic device underneath the display and between the display and the rear wall. The coherent fiber bundle may have fiber cores with bends that help conceal the housing from view around the edges of the display and thereby make the display appear borderless. 
     The coherent fiber bundle has filaments formed from elongated strands of binder. Each filament may include multiple fiber cores. Sheets of filaments are stacked and fused together to form the coherent fiber bundle. By aligning and fusing the sheets with respect to each other, the filaments become packed with a desired density and uniformity in the coherent fiber bundle. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of an illustrative electronic device with an image transport layer in accordance with an embodiment. 
         FIG. 2  is a cross-sectional view of a portion of an illustrative image transport layer formed using a coherent fiber bundle in accordance with an embodiment. 
         FIG. 3  is a perspective view of a portion of an image transport layer surface with compound curvature in accordance with an embodiment. 
         FIG. 4  is a top view of an illustrative electronic device in accordance with an embodiment. 
         FIG. 5  is a side view of illustrative equipment for forming filaments from elongated strands of binder with embedded fiber cores in accordance with an embodiment. 
         FIG. 6  is a side view of illustrative equipment for forming sheets of fused filaments for an image transport layer in accordance with an embodiment. 
         FIG. 7  is a cross-sectional view of an illustrative alignment wheel for use in equipment that forms filament sheets such as the illustrative equipment of  FIG. 6  in accordance with an embodiment. 
         FIG. 8  is a cross-sectional view of illustrative sheet fusing rollers for use in equipment that forms filament sheets such as the illustrative equipment of  FIG. 6  in accordance with an embodiment. 
         FIG. 9  is a cross-sectional side view of an illustrative bobbin with channels into which sheets of filaments may be placed during sheet packing operations in accordance with an embodiment. 
         FIG. 10  is a cross-sectional view of an illustrative bobbin and associated sheets of filaments in accordance with an embodiment. 
         FIG. 11  is a diagram of an illustrative pair of adjacent sheets of filaments showing how sheet-packed coherent fiber bundle material may be formed in accordance with an embodiment. 
         FIG. 12  is a cross-sectional side view of an illustrative sheet-packed coherent fiber bundle in accordance with an embodiment. 
         FIG. 13  is a flow chart of illustrative operations involved in forming an electronic device with a sheet-packed coherent fiber bundle in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     An electronic device may have a display. The display may have an array of pixels for creating an image. The image may be visible through transparent structures that overlap the array of pixels. These structures may include an image transport layer such as a coherent fiber bundle overlapped by a clear display cover layer. 
     The coherent fiber bundle may be included in the electronic device to help minimize display borders or to otherwise create a desired appearance for the display. The coherent fiber bundle may have an input surface that receives an image from an array of pixels and a corresponding output surface to which the image is transported from the input surface. A layer of glass, polymer, or other clear material may be used to form a display cover layer that protects the output surface. A user viewing the electronic device will view the image from the array of pixels as being located on the output surface. In some arrangements, image transport layers formed from coherent fiber bundles and/or protective cover layers can be formed over components other than displays. 
     In configurations in which the input and output surfaces of an image transport layer such as a coherent fiber bundle have different shapes, the image transport layer may be used to warp the image produced by the array of pixels. For example, the shape of the image can be transformed and the effective size of the image can be changed as the image passes through the image transport layer. In some configurations, edge portions of the image are stretched outwardly to help minimize display borders. 
     Glass and/or polymer may be used in forming image transport layer structures. Display cover layers for protecting underlying display structures such as pixel arrays and image transport layers may be formed from transparent materials such as glass, clear polymer, or crystalline material such as sapphire. 
     A cross-sectional side view of a portion of an illustrative electronic device having a display that includes an image transport layer is shown in  FIG. 1 . In the example of  FIG. 1 , device  10  is a portable device such as a cellular telephone, wristwatch, or tablet computer. In general, any type of electronic device may have an image transport layer such as a desktop computer, a voice-control speaker, a television or other non-portable display, a head-mounted device, an embedded system such as a system built into a vehicle or home, an electronic device accessory, and/or other electronic equipment. 
     Device  10  includes a housing such as housing  12 . Housing  12  may be formed from polymer, metal, glass, crystalline material such as sapphire, ceramic, fabric, fibers, fiber composite material, natural materials such as wood and cotton, other materials, and/or combinations of such materials. Housing  12  may be configured to form housing walls. The housing walls may enclose one or more interior regions such as interior region  24  and may separate interior region  24  from exterior region  22 . For example, housing  12  may have a rear housing wall on rear face R and this rear housing wall may separate interior region  24  from the exterior region. In some configurations, an opening may be formed in housing  12  for a data port, a power port, to accommodate audio components, or to accommodate other devices. Clear housing regions may be used to form optical component windows. Dielectric housing structures may be used to form radio-transparent areas for antennas and wireless power components. 
     Electrical components  18  may be mounted in interior region  24 . Electrical components  18  may include integrated circuits, discrete components, light-emitting components, sensors, and/or other circuits and may, if desired, be interconnected using signal paths in one or more printed circuits such as printed circuit  20 . If desired, one or more portions of the housing walls may be transparent (e.g., so that light associated with an image on a display or other light-emitting or light-detecting component can pass between interior region  24  and exterior region  22 ). 
     Electrical components  18  may include control circuitry. The control circuitry 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 the control circuitry may be used to control the operation of device  10 . For example, the processing circuitry may use sensors and other input-output circuitry to gather input and to provide output and/or to transmit signals to external equipment. 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. The control circuitry may include wired and/or wireless communications circuitry (e.g., antennas and associated radio-frequency transceiver circuitry such as cellular telephone communications circuitry, wireless local area network communications circuitry, etc.). The communications circuitry of the control circuitry may allow device  10  to communicate with other electronic devices. For example, the control circuitry (e.g., communications circuitry in the control circuitry) may be used to allow wired and/or wireless control commands and other communications to be conveyed between devices such as cellular telephones, tablet computers, laptop computers, desktop computers, head-mounted devices, handheld controllers, wristwatch devices, other wearable devices, keyboards, computer mice, remote controls, speakers, accessory displays, accessory cameras, and/or other electronic devices. Wireless communications circuitry may, for example, wirelessly transmit control signals and other information to external equipment in response to receiving user input or other input from sensors or other devices in components  18 . 
     Input-output circuitry in components  18  of device  10  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. The input-output circuitry may include input devices that gather user input and other input and may include output devices that supply visual output, audible output, or other output. 
     Output may be provided using light-emitting diodes (e.g., crystalline semiconductor light-emitting diodes for status indicators and/or displays, organic light-emitting diodes in displays and other components), lasers, and other light-emitting devices, audio output devices (e.g., tone generators and/or speakers), haptic output devices (e.g., vibrators, electromagnetic actuators, piezoelectric actuators, and/or other equipment that supplies a user with haptic output), and other output devices. 
     The input-output circuitry of device  10  (e.g., the input-output circuitry of components  18 ) may include sensors. Sensors for device  10  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 a display, a two-dimensional capacitive touch sensor and/or a two-dimensional force sensor overlapping a display, and/or a touch sensor or force sensor that forms a button, trackpad, or other input device not associated with a display), and other sensors. Touch sensors for a display or for other touch components may be based on an array of capacitive touch sensor electrodes, acoustic touch sensor structures, resistive touch components, force-based touch sensor structures, a light-based touch sensor, or other suitable touch sensor arrangements. If desired, a display may have a force sensor for gathering force input (e.g., a two-dimensional force sensor may be used in gathering force input on a display). 
     If desired, the sensors may include optical sensors such as optical sensors that emit and detect light, 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, ultrasonic 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 (e.g., sensors that gather position information, three-dimensional radio-frequency images, and/or other information using radar principals or other radio-frequency sensing), depth sensors (e.g., structured light sensors and/or depth sensors based on stereo imaging devices), 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, three-dimensional sensors (e.g., time-of-flight image sensors, pairs of two-dimensional image sensors that gather three-dimensional images using binocular vision, three-dimensional structured light sensors that emit an array of infrared light beams or other structured light using arrays of lasers or other light emitters and associated optical components and that capture images of the spots created as the beams illuminate target objects, and/or other three-dimensional image sensors), facial recognition sensors based on three-dimensional image sensors, and/or other sensors. 
     In some configurations, components  18  may include mechanical devices for gathering input (e.g., buttons, joysticks, scrolling wheels, key pads with movable keys, keyboards with movable keys, and other devices for gathering user input). During operation, device  10  may use sensors and/or other input-output devices in components  18  to gather user input (e.g., buttons may be used to gather button press input, touch and/or force sensors overlapping displays can be used for gathering user touch screen input and/or force input, touch pads and/or force sensors may be used in gathering touch and/or force input, microphones may be used for gathering audio input, etc.). The control circuitry of device  10  can then take action based on this gathered information (e.g., by transmitting the information over a wired or wireless path to external equipment, by supplying a user with output using a haptic output device, visual output device, an audio component, or other input-output device in housing  12 , etc.). 
     If desired, electronic device  10  may include a battery or other energy storage device, connector ports for supporting wired communications with ancillary equipment and for receiving wired power, and other circuitry. In some configurations, device  10  may serve as an accessory and/or may include a wired and/or wireless accessory (e.g., a keyboard, computer mouse, remote control, trackpad, etc.). 
     Device  10  may include one or more displays such as display  14 . The displays may, for example, include an organic light-emitting diode display, a liquid crystal display, a display having an array of pixels formed from respective light-emitting diodes (e.g., a pixel array having pixels with light-emitting diodes formed from respective crystalline light-emitting diode dies such as micro-light-emitting diode dies), and/or other displays. The displays may include rigid display structures and/or may be flexible displays. For example, a light-emitting diode display may have a polymer substrate that is sufficiently flexible to be bent. Display  14  may have a rectangular pixel array or a pixel array of another shape for displaying images for a user and may therefore sometimes be referred to as a pixel array. Display  14  may also sometimes be referred to as a display panel, display layer, or pixel layer. Each pixel array in device  10  may be mounted under a transparent housing structure (sometimes referred to as a transparent display cover layer, protective cover layer structures, etc.). 
     In the example of  FIG. 1 , display (pixel array)  14  is mounted under protective layer(s)  32 . Layer  32  (which may be considered to form a portion of the housing of device  10 ), covers front face F of device  10 . Configurations in which opposing rear face R of device  10  and/or sidewall portions of device  10  have transparent structures covering displays and other optical components may also be used. 
     As shown in  FIG. 1 , layer  32  may include image transport layer  16  and display cover layer  30 . Display cover layer  30  serves as a protective outer layer for device  10  and display  14 . Display cover layer  30  may be formed from a layer of glass, clear polymer, crystalline material such as sapphire or other crystalline material, and/or other transparent material. The presence of layer  30  may help protect the outer surface of layer  16  from scratches. If desired, layer  30  may be omitted and layer  16  may serve as a protective display cover layer (e.g., in configurations in which a thin-film protective coating is present on the outer surface of layer  16 , in configurations in which layer  16  is formed from hard material such as glass, and/or in other configurations in which layer  16  is resistant to scratching). A layer of adhesive and/or other structures may be formed between layer  30  and image transport layer  16  and/or may be included elsewhere in the stack of layers on display  14 . 
     During operation, the pixels of display  14  produce image light that passes through image transport layer  16 . In configurations in which image transport layer  16  is formed from a coherent fiber bundle, image transport layer  16  has optical fibers  16 F. The fibers or other optical structures of image transport layer structures such as image transport layer  16  transport light (e.g., image light and/or other light) from one surface (e.g., an input surface of layer  16  that faces display  14 ) to another (e.g., an output surface of layer  16  that faces viewer  28 , who is viewing device  10  in direction  26 ). As the image presented to the input surface of layer  16  is transported to the output surface of layer  16 , the integrity of the image light is preserved. This allows an image produced by an array of pixels to be transferred from an input surface of a first shape at a first location to an output surface with a different shape (e.g., a shape with a footprint that differs from that of the input surface, a shape with a curved cross-sectional profile, a shape with a region of compound curvature, and/or a shape with other desired features). 
     Image transport layer  16  may therefore move the location of an image and may optionally change the shape of the surface on which the image is presented. In effect, viewer  28  will view the image from display  14  as if the image were generated on the output surface of image transport layer  16 . In arrangements in which the image from display  14  is warped (geometrically distorted) by image transport layer  16 , digital pre-distortion techniques or other compensation techniques may be used to ensure that the final image viewed on the output surface of image transport layer  16  has a desired appearance. For example, the image on display  14  may be prewarped so that this prewarped image is warped by an equal and opposite amount upon passing through layer  16 . In this way, the prewarped image is effectively unwarped by passage through layer  16  will not appear distorted on the output surface. 
     In configurations of the type shown in  FIG. 1 , device  10  may have four peripheral edges and a rectangular footprint when viewed in direction  26  or may have other suitable shapes. To help minimize the size of inactive display borders as a user is viewing front face F of device  10  as shown in  FIG. 1 , the shapes of fibers  16 F along the periphery of layer  16  may be deformed outwardly as shown in  FIG. 1 . These fibers  16 F each have an outwardly bent segment that bends away from surface normal n of the center of layer  30  (e.g., away from an axis parallel to the Z axis of  FIG. 1 ) and each have an inwardly bent segment that bends back towards surface normal n to help direct output light towards viewer  28 . 
     The deformed shapes of fibers  16 F (e.g., the bends in fibers  16 F along their lengths and/or the corresponding deformations made to optical filaments in Anderson localization material in layer  16 ) may help distribute image light laterally outwards in the X-Y plane so that the effective size of display  14  is enlarged and the image produced by display  14  covers some or all of the sidewalls of housing  12  or other peripheral portions of device  10  when the image on front face F is being viewed by viewer  28 . For example, the bent shapes of fibers  16 F of  FIG. 1  may help shift portion of the displayed image laterally outward in the X-Y plane along the edges and corners of device  10  to block the edges of device  10  (e.g., the periphery of housing  12 ) from view. This helps make the display of device  10  appear borderless to viewer  28 . In some arrangements, the portions of fibers  16 F at the outermost surface of layer  16  are oriented parallel or nearly parallel with viewing direction  26  and the Z axis of  FIG. 1 , which helps ensure that some or all of the light that has passed through layer  16  will travel in the Z direction and be viewable by viewer  28 . 
       FIG. 2  is a cross-sectional view of a portion of image transport layer  16  in an illustrative configuration in which image transport layer  16  is formed from a coherent fiber bundle. Fibers  16 F for layer  16  may have any suitable configuration. As shown in the example of  FIG. 2 , fibers  16 F may each have a core such as core  16 F- 1 . Cores  16 F- 1  and the other structures of image transport layer (e.g., cladding structures, binder, etc.)  16  may be formed from materials such as polymer, glass, crystalline material such as sapphire, and/or other materials. Some or all of these materials may be transparent. Arrangements in which some of the materials absorb light and/or have non-neutral colors or other light filtering properties may also be used. 
     Fiber cores  16 F- 1  may be formed from transparent material of a first refractive index and may be surrounded by cladding of a second, lower refractive index to promote light guiding in accordance with the principal of total internal reflection. In some arrangements, a single coating layer on cores  16 F- 1  may be used to form the cladding. In other arrangements, two or more coating layers on cores  16 F- 1  may be used to form the cladding. Clad fibers may be held together using binder  16 FB, which serves to fill the interstitial spaces between the clad fibers and join fibers  16 F together. In some configurations, stray light absorbing material may be incorporated into layer  16  (e.g., into some of the cores, cladding, and/or binder). The stray light absorbing material may be, for example, polymer, glass, or other material into which light-absorbing material such as dye and/or pigment has been incorporated. 
     In an illustrative configuration, layer  16  may have inner coating layers  16 F- 2  that are formed directly on the outer surfaces of cores  16 F- 1  and outer coating layers  16 F- 3  that are formed directly on the outer surfaces of layers  16 F- 2 . Additional coating layers (e.g., three or more coating layers) or fewer coating layers (e.g., a single coating layer) may be formed on fiber cores  16 F- 1 , if desired. Stray light-absorbing material may be used in layers  16 F- 2  and/or  16 F- 3  or other coating layer(s) on cores  16 F- 1 . In an illustrative arrangement, layers  16 F- 2  and  16 F- 3 , which may sometimes be referred to as forming first and second cladding portions (or first and second claddings) of the claddings for fiber cores  16 F- 1 , may respectively be formed from transparent material and stray light-absorbing material. Other arrangements may be used, if desired (e.g., arrangements in which stray light absorbing material is incorporated into some or all of binder  16 FB, arrangements in which cores  16 F- 1  are formed directly in binder  16 FB without any intervening cladding, arrangements in which cores  16 F- 1  are coated with inner and outer transparent claddings and an interposed intermediate stray-light-absorbing cladding, arrangements in which cores  16 F- 1  are covered with a single stray-light-absorbing cladding, arrangements in which some or all of fibers  16 F are provided with longitudinally extending filaments  16 F- 4  of stray light absorbing material located, for example, on or in any of the cladding layers, etc.). 
     In configuration in which fibers  16 F have claddings formed from two or more separate cladding layers, the cladding layers may have the same index of refraction or the outermost layers may have lower refractive index values (as examples). Binder  16 FB may have a refractive index equal to the refractive index of the cladding material, lower than the refractive index of the cladding material to promote total internal reflection, or higher than the refractive index of the cladding material (as examples). For example, each fiber core  16 F- 1  may have a first index of refraction and the cladding material surrounding that core may have a second index of refraction that is lower than the first index of refraction by an index difference of at least 0.05, at least 0.1, at least 0.15, at least 10%, at least 20%, less than 50%, less than 30%, or other suitable amount. The binder refractive index may be the same as that of some or all of the cladding material or may be lower (or higher) than the lowest refractive index of the cladding by an index difference of at least 0.05, at least 0.1, at least 0.15, at least 10%, at least 20%, less than 50%, less than 30%, or other suitable amount. 
     The diameters of cores  16 F- 1  may be, for example, at least 5 microns, at least 7 microns, at least 8 microns, at least 9 microns, less than 40 microns, less than 17 microns, less than 14 microns, less than 11 microns, or other suitable diameter. Fibers  16 F (including cores and claddings) may have diameters of at least 6 microns, at least 7 microns, at least 8 microns, at least 9 microns, less than 50 microns, less than 17 microns, less than 14 microns, less than 11 microns, or other suitable diameter. 
     Fibers  16 F may generally extend parallel to each other in image transport layer  16  (e.g., the fibers may run next to each other along the direction of light propagation through the fiber bundle). This allows image light or other light that is presented at the input surface to layer  16  to be conveyed to the output surface of layer  16 . 
     Image transport layers can be used to transport an image from a first (input) surface (e.g., the surface of a pixel array) to a second (output) surface (e.g., a surface in device  10  with compound curvature or other curved and/or planar surface shape) while preserving the integrity of the image. A perspective view of an illustrative corner portion of image transport layer  16  is shown in  FIG. 3 . In the example of  FIG. 3 , layer  16  has edge portions  40  and  42  with surfaces that curve about axes  44  and  46 , respectively. These portions of layer  16  may extend parallel to the straight sides of device  10  (as an example) and are characterized by curved surfaces that can be flattened into a plane without distortion (sometimes referred to as developable surfaces). At the corner of image transport layer  16  of  FIG. 3 , image transport layer  16  has curved surface portions CP with compound curvature (e.g., a surface that can only be flattened into a plane with distortion, sometimes referred to as a surface with Gaussian curvature). In a rectangular layout with curved corners, image transport layer  16  may have four corners with compound curvature. Image transport layers of other shapes (e.g., circular outlines, etc.) may also have surfaces with compound curvature (e.g., dome-shaped surfaces, an edge surface of compound curvature that runs along the circular periphery of a central circular planar region, etc.). When overlapped by layer  30 , the overlapping portions of layer  30  may have corresponding surfaces with compound curvature. When selecting the size and shape of the output surface of layer  16  and therefore the size and shape of the image presented on the output surface, the use of an image transport layer material with compound curvature can provide design flexibility. In general, layer  30  and layer  16  may have planar surfaces and/or surfaces with curved cross-sectional profiles. 
     In some arrangements, device  10  may include support structures such as wearable support structures. This allows device  10  to be worn on a body part of a user (e.g., the user&#39;s wrist, arm, head, leg, or other portion of the user&#39;s body). As an example, device  10  may include a wearable band, such as band  50  of  FIG. 4 . Band  50 , which may sometimes be referred to as a wristband, wrist strap, or wristwatch band, may be formed from polymer, metal, fabric, leather or other natural materials, and/or other material, may have links, may stretch, may be attached to housing  12  in a fixed arrangement, may be detachably coupled to housing  12 , may have a single segment or multiple segments joined by a clasp, and/or may have other features that facilitate the wearing of device  10  on a user&#39;s wrist. 
     If desired, image transport layer material may be formed from filaments of material each of which include multiple fiber cores. Filaments may, as an example, be formed using an extrusion process. An illustrative extrusion tool for forming filaments of image transport layer material is shown in  FIG. 5 . As shown in  FIG. 5 , extruder  60  may include hoppers  62  that contain different types of material to be extruded (e.g., different polymers such as binder polymer and fiber core polymer). The material from hoppers  62  may be provided to coextrusion die set  64 . During coextrusion, the material from hoppers  62  is coextruded through extrusion die set  64  and forms one or more elongated extruded members such as extruded filament  66 , which exits extrusion die set  64  in direction  68 . In the example of  FIG. 5 , filament  66  includes multiple fiber cores  16 FC (see, e.g., cores  16 - 1  of  FIG. 2 ) embedded in an elongated strand of binder  16 FB (see, e.g., binder  16 FB of  FIG. 2 ). A single filament  66  is being extruded from extrusion die set  64  in  FIG. 5 . If desired, multiple filaments  66  may be extruded in parallel from die set  64  (e.g., to form bundles of filaments  66  at the output of die set  64 ). In such configurations, filaments  66  may be debundled prior to subsequent operations (e.g., before fusing a layer of filaments  66  together to form a sheet of image transport layer material). 
     As shown in  FIG. 5 , extrusion die set  64  may include one or more layers with channels configured to distribute fiber core material into multiple cores  16 FC embedded in binder  16 FB during extrusion. Filaments such as filament  66  may have circular cross-sectional shapes and may contain any suitable number of fiber cores  16 FC (e.g., at least 3 fiber cores  16 FC, at least 10 fiber cores  16 FC, at least 30 fiber cores  16 FC, at least 100 fiber cores  16 FC, at least 500 fiber cores  16 FC, at least 2500 fiber cores  16 FC, less than 20,000 fiber cores  16 FC, less than 4000 fiber cores  16 FC, less than 500 fiber cores  16 FC, less than 100 fiber cores  16 FC, and/or other suitable number of fiber cores  16 FC). 
     When it is desired to join the filaments produced by extruder  60  (e.g., extruded strands such as multi-core filament  66  of  FIG. 5  or other elongated polymer members), the filaments may be placed in fusion equipment, which fuses the filaments by applying heat and pressure (e.g., heat and pressure that helps fuse the binder material of the filaments together). In-line fusion tools (e.g., fusers with rollers), laser-fusion equipment, fusion equipment that involves wrapping filaments into channels using computer-controlled equipment that maintains desired angular orientations and tensions computer-controlled, and/or other illustrative fusing tools may be used to fuse filaments together to form image transport layer material. 
     To help ensure satisfactory alignment of filaments  66  with respect to each other during fusion (and therefore ensure satisfactory alignment of fiber cores  16 FC in image transport layer  16  and a desired low level of visual artifacts in the coherent fiber bundle), it may be desirable to fuse a single layer of filaments  66  together to form a filament sheet (sometimes referred to as a coherent fiber bundle sheet, a sheet of filaments, a sheet of image transport layer material, etc.). Multiple sheets can then be stacked and fused to form a coherent fiber bundle in which filaments are packed together with a desired filament alignment and density. Such coherent fiber bundle material, which may sometimes be referred to as sheet-packed coherent fiber bundle material, sheet-packed image transport layer material, sheet-stacked image transport layer material, a sheet-packed coherent fiber bundle, etc., may exhibit satisfactory image transport qualities (e.g., low amounts of visual artifacts). 
     Sheets of image transport layer material (e.g., sheets of fused filaments) can be formed using equipment of the type shown in  FIG. 6  (as an example).  FIG. 6  is a cross-sectional view of an illustrative fusion tool for producing fused filament sheets. As shown in  FIG. 6 , tool  70  may include filament source  72 . Filament source  72  may include multiple single-filament spools  74 , each of which may dispense a respective multi-core filament  66  (see, e.g., filament  66  of  FIG. 5 ). Each spool  74  may be mounted on a tension controlling dancer arm and may have a respective separate computer-controlled motor. In configurations in which extruder  60  produces bundles of filaments  66 , debundling equipment may be used to separate bundles of filaments  66  into individual filaments  66  each of which may be stored on a respective one of spools  74 . 
     Guide bars  76  may be used to distribute a layer of multiple parallel filaments  66  to one or more aligning wheels  78 . Guide bars  76  may have smooth guide rollers to help reduce friction. Aligning wheels  78  may include springs and/or other tensioning mechanisms and may have a tunable wheel gap to receive and align filaments  66 . As filaments  66  pass through wheels  78 , filaments  66  are aligned so as to form a sheet  66 ′ of aligned unfused filaments of width W. Unfused filament sheet  66 ′ may be passed through a series of interleaved vertically oriented tensioning rods  80  that can be adjusted to increase or decrease friction and therefore control sheet tension. 
     Rollers  82 , which may sometimes be referred to as fusion rollers or pre-fusion rollers, apply heat and/or pressure to the filaments of sheet  66 ′ to form a sheet of joined (e.g., fused) filaments  66 . This fused sheet of filaments (fused filament sheet  66 ″) may be received by a take-up system such as bobbin  84 . Subsequent fusing operations on bobbin  84  or in separate fusing equipment may be used to form a block of sheet-packed coherent fiber bundle material from multiple stacked filament sheets. 
       FIG. 7  is a cross-sectional side view of an illustrative alignment wheel for tool  70 . As shown in  FIG. 7 , alignment wheel  78  may have a pair of parallel disc-shaped wheel members  94  mounted on a common shaft such as shaft  92 . During operation, wheel  78  rotates about axis  90 , which is aligned with shaft  92 . Wheel members  94  may be separated by a gap  96  that is configured to accept only a single layer of filaments  66 . This ensures that filaments  66  will be aligned in a planar array (in a row) to form a planar filament sheet when passing through wheel  78 . 
     Fusion rollers  82  may include mating rollers such as roller  82 M and roller  82 F of  FIG. 8 . Roller  82 F may rotate about axis  102  as roller  82 M rotates in the opposite direction about axis  106 . Roller  82 M protrudes into gap  108  between roller side walls  114  of roller  82 F, so that filaments  66  are compressed between surface  110  of roller  82 F and opposing surface  112  of roller  82 M. By applying heat and/or pressure while filaments  66  pass through rollers  82 F and  82 M, filaments  66  of unfused sheet  66 ′ are joined to form joined (fused) filaments  66  of fused sheet  66 ″. 
       FIG. 9  is a cross-sectional side view of bobbin  84  of  FIG. 6 . As shown in  FIG. 9 , bobbin  84  may have non-circular take-up wheel  120  that rotates on shaft  126  about rotational axis  128  in direction  130 . Wheel  120  may, for example, have a hexagonal or octagonal shape (as examples). Flat surfaces  122  of wheel  120  allow sheets  66 ″ to be stacked to form blocks of filaments  66 , where filaments  66  are straight and run parallel to each other. For example, a hexagonal shape for wheel  120  may allow six sections of coherent fiber bundle material to be formed each of which contains a respective set of parallel filaments  66 . Bobbin  84  may have guide walls  124  that help laterally align (into and out of the page in the orientation of  FIG. 9 ) the sheets of fused filaments  66  being wound onto wheel  120 . 
     One or more sheets of filaments  66  may be wound onto wheel  120 . In the example of  FIG. 9 , a first fused filament sheet (sheet  66 A) is being fed in direction  134  onto bobbin  84  while a second fused filament sheet (sheet  66 B, which may be laterally offset along dimension X by half of a filament diameter with respect to sheet  66 A) is being fed in direction  136  onto bobbin  84 . Pinch rollers  140  and  142 , which may be mounted on movable spring-loaded dancer arms, rotate about respective axes  144  and  146  while pressing inwardly on filaments  66  toward surfaces  122 . In this way, pinch rollers  140  and  142  hold previously wound sheets of filaments  66  flat to prevent buckling and thereby ensure satisfactory winding and alignment of subsequently stacked layers of filaments. 
       FIG. 10  is a cross-sectional side view of bobbin  84  showing how multiple sub-sheets may be wound around wheel  120  into the channels formed between guide walls  124 . In the example of  FIG. 10 , a sheet of filaments on surface  122  of wheel  120  has been formed by winding a first sheet portion  66 P- 1  onto one half of wheel  120  and a second sheet portion  66 P- 2  onto an adjacent second half of wheel  120 . There may be three or more laterally adjacent sheet portions that are wound onto wheel  120  in this way, if desired. Multiple sheet portions may be wound onto wheel  120  simultaneously (to deposit three laterally adjacent sheet portions at the same time), laterally adjacent stack portions may be deposited in series, multiple laterally adjacent sheet portion stacks may be formed one after the next, or other patterns of sheet winding may be used to when stacking sheets of filaments  66  onto wheel  120 . 
     After filaments  66  have been stacked to a desired thickness H (e.g., a height equal to the total sheet width or other suitable size), filaments  66  may be fused under vacuum to form a block of image transport layer material. If desired, the channels of bobbin  84  may receive respective heated dies such as die  150 . Dies such as die  150  may press inwardly in direction  152  against the stacked sheets of filaments  66  so that filaments  66  are compressed between inwardly facing planar surface  154  of die  150  and outwardly facing planar surface  122  of wheel  120 , while being laterally constrained (along dimension X) by the inner surfaces of guide walls  124 . In this type of configuration, bobbin  84  serves as a fusion tool. If desired, sheets  66 ″ may be divided into individual planar sheets (e.g., using a sheet slicing tool that cuts rectangular fused sheets from a continuous strip of fused sheet material at the exit to fusion rollers  84  of  FIG. 6 ). When individual planar sheets of fused fibers are formed in this way, a die with a rectangular cavity (or other suitable cavity shape) may receive a set of stacked planar sheets and may pack and fuse these sheets using heat and pressure to form a block of sheet-packed coherent fiber bundle material. 
     By forming image transport layer material from alternating layers of laterally offset filament sheets, filaments  66  may be packed with a desired density and alignment to ensure satisfactory image quality. An illustrative arrangement for aligning sheets of filaments while forming sheet-packed coherent fiber bundle material is shown in  FIGS. 11 and 12 . 
       FIG. 11  is a cross-sectional side view of two laterally shifted sheets of filaments  66 . The first sheet (e.g., odd sheet  66 A) has a planar layer of fused filaments  66 , each of which contains multiple fiber cores  16 FC. The surface of sheet  66 A may be planar and/or may have residual protrusions associated with the individual filaments  66  that were joined together to form sheet  66 A. Similarly, the second sheet of  FIG. 11  (even sheet  66 B) has a planar layer of fused filaments  66 , each of which contains multiple fiber cores  16 FC. 
     Sheets  66 A and  66 B (and subsequent odd and even filament sheets formed on top of these sheets in alternation) may be oriented with respect to each other during stacking to help pack filaments  66  densely and in accurate alignment. In particular, each sheet that is wound onto surface  122  of bobbin  84  may have filaments that are laterally offset (filament centers that are laterally offset) with respect to each other along dimension X (parallel to rotational axis  128  of bobbin  84  and wheel  120 ). It may also be desirable for sheets  66 A and  66 B to have different numbers of filaments. For example, if sheet  66 A has N filaments  66 , sheet  66 B may have N−1 filaments to help align filaments  66  of sheet  66 B appropriately with respect to the edges of sheet  66 A (e.g., avoiding overhang along the sheet edge). 
     As shown in the example of  FIG. 11 , sheet  66 A is formed from fused filaments  66  that are joined (e.g., fused) along boundaries FB 1 , whereas sheet  66 B is formed from fused filaments  66  that are joined (e.g., fused) along boundaries FB 2 . To help reduce voids and ensure satisfactorily alignment, sheet  66 B is laterally offset (along dimension X across the width of sheet  66 A) with respect to sheet  66 A by half of the distance DF between a pair of adjacent filament boundaries FB 1 . This distance DF/2 is approximately equal to the radius of filaments  66  and is equal to half of the distance between adjacent filament boundaries FB 2  in sheet  66 B. In a coherent fiber bundle in which even and odd sheets of filaments alternate, the filament centers of the filaments of the even sheets and the filament centers of the filaments of the odd sheets are laterally offset in this way (e.g., the filament centers of alternating odd and even sheets are offset by DF/2 with respect to each other, which is equal to half of the filament-center-to-filament-center distance of the filaments in both types of sheets). At the same time, the filament centers of the even sheets are laterally aligned with respect to each other and the filament centers of the odd sheets are laterally aligned with respect to each other. 
     As shown in  FIG. 12 , a coherent fiber bundle (e.g., image transport layer  16 ) may be formed by fusing together filaments  66  that are packed together in a stack where sheets  66 A alternate with laterally offset sheets  66 B. With this sheet packing arrangements, one of even sheets  66 B is formed between each pair of odd sheets  66 A. The filaments of each sheet are laterally offset by DF/2 with respect to the filaments of the proceeding sheet in the stack. By laterally offsetting the filament centers of odd filament sheets by half of a filament diameter with respect to the filament centers of even filament sheets in this way, filaments  66  may be densely packed and accurately fused together with a desirably small amount of misalignment (waviness) along their lengths. Sheet-packed coherent fiber bundle material may then be thermally deformed (e.g., to form fiber bends of the type shown in  FIG. 1 ) and machined and polished to form image transport layer  16 . 
     Illustrative operations in forming sheet-packed coherent fiber bundle material for device  10  are shown in  FIG. 13 . During the operations of block  160 , a tool such as extrusion tool  60  may be used to extrude multi-core filaments such as filament  66 . Each filament may include multiple fiber cores  16 FC embedded in an elongated strand of binder  16 FB. The diameter of each filament  66  may be, for example, 100 microns, at least 20 microns, at least 60 microns, less than 150 microns, less than 500 microns, or other suitable size. Filaments  66  may be gathered on single-filament spools or may be gathered on spools in multi-filament bundles that are subsequently debundled into individual filaments  66  for source  72  of tool  70  ( FIG. 6 ). 
     During the operations of block  162 , filaments  66  are fused or otherwise joined into sheets such as fused sheet  66 ″ (e.g., using fusion rollers  82  of  FIG. 6 ). Alternating laterally offset sheets of filaments  66 A and  66 B are wound onto bobbin  84  and heat and pressure is applied (e.g., using die  150  of  FIG. 10 ) to form a sheet-packed coherent fiber bundle. 
     During the operations of block  164 , the sheet-packed coherent fiber bundle may be optionally deformed (thermally formed) by applying heat and pressure (e.g., in a heated mold). For example, the coherent fiber bundle (e.g., the block of image transport layer material formed from filaments  66 ) can be squeezed together so as to deform fiber cores  16 FC and cause fiber cores  16 FC to exhibit one or more bends along their lengths as shown in  FIG. 1 . 
     During the operations of block  166 , a saw or other equipment may be used to slice a layer of image transport layer material from the deformed image transport layer block. 
     This layer may, during the operations of block  168 , be shaped using grinding tools, polishing tools, and/or other equipment to form a finished version of image transport layer  16  (see, e.g., layer  16  of  FIG. 1 ). 
     During the operations of block  170 , display cover layer  30 , the polished sheet-packed coherent fiber bundle (image transport layer  16 ), display  14 , and other structures may be assembled into housing  12  to form electronic device  10 . For example, layers such as layers  30  and  16  and display  14  may be joined using layers of adhesive. Display  14 , layer  30 , layer  16 , and associated support structures and internal components can be coupled to housing  12  using adhesive, fasteners (e.g., screws), welds, press-fit joints, flexible engagement structures (e.g., springs, clips, etc.), and/or may be mounted to housing  12  using other mounting structures. 
     As described above, one aspect of the present technology is the gathering and use of information such as sensor information. 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: 20210122
Publication Date: 20221115
Grant Date: 20221115
Priority Date: 20200316
Inventors: LIN, WEI
CHANG, CHIH-YAO
GUPTA, NATHAN K.
Assignee: APPLE INC
CPC Classifications: [{"code": "G02F1/0115", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02F1/0115", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B6/0078", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B6/3604", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B6/02004", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/0115", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B6/0078", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B6/3604", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B6/02004", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B6/448", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B6/08", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 84000773