PATENT DOCUMENT

Publication Number: US-10840474-B2
Application Number: US-202016814890-A
Country: US
Kind Code: B2

Title: Electronic devices with 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 facilitate bending about the bend axis, the display may have layers such as a display cover layer with grooves or other recesses. The recesses form a flexible portion in the display layer. The display layer may be formed from glass or other materials that are transparent. Elastomeric material, fluids, and other materials may be placed in the recesses in the display layer. The material in the display layer may have an index of refraction that is matched to the index of refraction of the display layer. A hinge may be formed between rigid planar layers that are separated by a gap. Flexible layers that lie flush with opposing surfaces of the rigid planar layers may be used to span the gap.

Claims:
What is claimed is: 
     
       1. A foldable electronic device, comprising:
 a housing that bends about a bend axis; 
 an array of pixels located on a flexible substrate in the housing, wherein the array of pixels extends across the bend axis; and 
 a layer of glass through which the array of pixels displays images, wherein the layer of glass forms an outermost surface of the electronic device and has a groove that extends parallel to the bend axis. 
 
     
     
       2. The foldable electronic device defined in  claim 1  further comprising a flexible polymer material in the groove. 
     
     
       3. The foldable electronic device defined in  claim 2  wherein the flexible polymer material comprises an elastomeric polymer. 
     
     
       4. The foldable electronic device defined in  claim 2  wherein the flexible polymer material and the layer of glass have matching indices of refraction. 
     
     
       5. The foldable electronic device defined in  claim 1  wherein the groove extends only partially through the layer of glass. 
     
     
       6. The foldable electronic device defined in  claim 1  wherein the groove extends entirely through the layer of glass. 
     
     
       7. The foldable electronic device defined in  claim 1  wherein the layer of glass has an interior surface and wherein the groove is one of a series of grooves in the interior surface of the layer of glass. 
     
     
       8. The foldable electronic device defined in  claim 7  wherein the layer of glass has an exterior surface that forms the outermost surface of the electronic device and wherein the exterior surface extends across the series of grooves. 
     
     
       9. The foldable electronic device defined in  claim 7  further comprising a polymer material that is located in the grooves and between the grooves. 
     
     
       10. The foldable electronic device defined in  claim 1  wherein the housing comprises first and second housing portions coupled by a hinge that overlaps the bend axis. 
     
     
       11. An electronic device, comprising:
 a housing having first and second housing portions coupled by a hinge; 
 a pixel array in the housing, wherein the pixel array forms a first display region on the first housing portion and a second display region on the second housing portion and wherein the first display region is configured to rotate relative to the second display region; and 
 a rigid transparent cover layer that forms an exterior surface of the electronic device, wherein the rigid transparent cover layer has a first portion through which the first display region displays images and a second portion through which the second display region displays images, and wherein the first and second portions are separated by a flexible polymer material that overlaps the hinge. 
 
     
     
       12. The electronic device defined in  claim 11  wherein the flexible polymer material comprises an elastomeric polymer. 
     
     
       13. The electronic device defined in  claim 11  wherein the rigid transparent cover layer comprises a groove and wherein the flexible polymer material is located in the groove. 
     
     
       14. The electronic device defined in  claim 13  wherein the groove is one of a series of grooves in the rigid transparent cover layer and wherein the flexible polymer material is located between the grooves. 
     
     
       15. The electronic device defined in  claim 13  wherein the flexible polymer material and the rigid transparent cover layer have matching indices of refraction. 
     
     
       16. An electronic device, comprising:
 a housing having first and second housing portions that rotate relative to one another about a hinge axis; 
 an array of organic light-emitting diode pixels having first and second display regions that rotate relative to one another about the hinge axis; and 
 a transparent display cover layer having opposing exterior and interior surfaces and having a groove in the interior surface, wherein the exterior surface forms an outermost surface of the electronic device and extends across the groove. 
 
     
     
       17. The electronic device defined in  claim 16  wherein the groove is parallel to the hinge axis. 
     
     
       18. The electronic device defined in  claim 16  wherein the transparent display cover layer comprises glass. 
     
     
       19. The electronic device defined in  claim 18  further comprising a flexible polymer material in the groove. 
     
     
       20. The electronic device defined in  claim 16  wherein the groove extends only partially through the transparent display cover layer.

Description:
This application is a continuation of patent application Ser. No. 16/019,431, filed Jun. 26, 2018, which is a continuation of patent application Ser. No. 15/177,025, filed Jun. 8, 2016, which claims the benefit of provisional patent application No. 62/199,187, filed Jul. 30, 2015, all of which are hereby incorporated by reference herein in their entireties. 
    
    
     BACKGROUND 
     This relates generally to electronic devices, and, more particularly, to electronic devices with 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 integrated 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 facilitate bending of the display about the bend axis, the display may have one or more layers such as an outer display cover layer with grooves or other recesses. The display cover layer may be formed from glass or other transparent materials. The recesses may form a flexible portion in a display layer that allows glass or other transparent materials of the display layer to bend about the bend axis. 
     The grooves or other recesses may be filled with polymer or other materials. In some configurations, a display layer may have openings that are filled with liquids. In display layer arrangements with flexible glass or polymer structures, the material that fills the grooves or other openings in the display layer may have an index of refraction value that matches the index of refraction of the glass or polymer structures. 
     A hinge may be formed between rigid planar layers that are separated by a gap. The rigid planar layers may be glass layers or other transparent layers in a display or may be housing walls or other structural portions of an electronic device. Flexible layers that lie flush with opposing surfaces of the rigid planar layers may be used to span the gap and form the hinge. 
    
    
     
       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 display cover layer with a flexible portion in accordance with an embodiment. 
         FIG. 6  is a cross-sectional side view of an illustrative display having display layers that extend between planar display cover layer portions and that span a flexible display cover layer portion that lies between the planar display cover layer portions in accordance with an embodiment. 
         FIG. 7  is a cross-sectional side view of an illustrative display having display layers that extend under first and second planar display layer portions and that do not overlap a flexible display cover layer portion that lies between the planar display layer portions in accordance with an embodiment. 
         FIG. 8  is a perspective view of the inner surface of an illustrative display cover layer having a series of parallel grooves that run parallel to a bend axis for the display cover layer in accordance with an embodiment. 
         FIGS. 9, 10, 11, 12, and 13  are cross-sectional side views of flexible display cover layer regions having grooves with different configurations in accordance with an embodiment. 
         FIG. 14  is a cross-sectional side view of a portion of a display cover layer with a locally thinned region to enhance flexibility in accordance with an embodiment. 
         FIG. 15  is a cross-sectional side view of the structure of  FIG. 15  in a bent configuration in accordance with an embodiment. 
         FIG. 16  is a cross-sectional side view of an illustrative display cover layer with a flexible portion covered with a hard coating layer in accordance with an embodiment. 
         FIG. 17  is a cross-sectional side view of a display cover layer of the type shown in  FIG. 16  in a configuration in which the hard coating layer extends across planar rigid portions of the display cover layer in addition to an interposed flexible portion in accordance with an embodiment. 
         FIG. 18  is a cross-sectional side view of a display cover layer with grooves to form a flexible region and with a hard coating layer that covers the outer surface of the display cover layer in accordance with an embodiment. 
         FIGS. 19, 20, and 21  are top views of illustrative display cover layer groove patterns to enhance flexibility in accordance with an embodiment. 
         FIG. 22  is a top view of an illustrative display cover layer with radially symmetric grooves such as concentric circular grooves to provide the display cover layer with the ability to flex into a dome shape in accordance with an embodiment. 
         FIG. 23  is a top view of an illustrative display cover layer with hexagonal grooves in accordance with an embodiment. 
         FIGS. 24, 25, and 26  are top views of additional display cover layer recess patterns in accordance with an embodiment. 
         FIG. 27  is a cross-sectional side view of an illustrative display cover layer having a sliding support structure for a thinned region of the display cover layer in accordance with an embodiment. 
         FIG. 28  is a cross-sectional side view of an illustrative multilayer display layer such as a display cover layer in a configuration in which a flexible portion of the display layer has layers that are not attached to each other to facilitate bending in accordance with an embodiment. 
         FIG. 29  is a cross-sectional side view of an illustrative display cover layer with multiple layers and fluid-filled regions in accordance with an embodiment. 
         FIG. 30  is a cross-sectional side view of illustrative flexible structures for a hinge or other flexible portion of an electronic device in accordance with an invention. 
         FIG. 31  is a cross-sectional side view of the flexible structures of  FIG. 30  in a bent configuration in accordance with an embodiment. 
         FIG. 32  is a cross-sectional side view of an illustrative display having a thinned region in a bent configuration in accordance with an embodiment. 
         FIG. 33  is a cross-sectional side view of an illustrative display having a thinned region that is adjacent to support structures with eased edges in accordance with an embodiment. 
         FIG. 34  is a cross-sectional side view of an illustrative hinge structure or other flexible structure formed from multiple layers of flexible structures in accordance with an embodiment. 
         FIG. 35  is a cross-sectional side view of an illustrative flexible structure for an electronic device 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), or pixels based on other display technologies. Display  14  may be formed from a single display panel (e.g., a single organic light-emitting diode layer) or may be formed form two panels (e.g., two organic light-emitting diode layers, two liquid crystal display modules, etc.). 
     In a configuration with a single display panel, the center of the display panel may be formed using flexible structures. 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 . As shown in  FIG. 1 , for example, display  14  may have three areas such as areas  14 A,  14 B, and  14 C. In areas  14 A and  14 C, 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). Flexible area  14 B forms a strip that lies between areas  14 A and  14 C. 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., 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 a configuration with two display panels, a first of the two panels may form a rigid display in area  14 A and a second of the two display panels may form a rigid display in area  14 C. In flexible area  14 B, the display structures that form the two display panels may be omitted and the overlapping display cover layer for display  14  may be provided with grooves or other structures to facilitate bending. 
     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). 
     As shown in  FIG. 5 , the display cover layer for display  14  (i.e., display cover layer  24 ) may have outer portions  24 A and  24 C that are formed on opposing sides of center portion  24 B. Outer portions  24 A and  24 C may, for example, be rigid planar layers. Configurations in which portions  24 A and  24 C have non-planar shapes and/or are formed from flexible structures may also be used. Between rigid planar portions  24 A and  24 C of display cover layer  24 , display cover layer  24  may have a flexible portion such as 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 . 
       FIG. 6  is a cross-sectional side view of display  14  is an illustrative configuration in which display  14  has a single panel (display panel  26 ) that is overlapped by rigid areas  14 A and  14 C and that spans central flexible area  14 B (i.e., the rectangular strip running parallel to axis  22  between areas  14 A and  14 C).  FIG. 7  is a cross-sectional side view of display  14  in an illustrative configuration in which display  14  has display structures  26  that are formed from two separate display panels. Display panel  26 A is located under rigid display cover layer portion  24 A and display panel  26 C is located under rigid display cover layer portion  24 C. Flexible display cover layer portion  24 B lies between rigid display cover layer portions  24 A and  24 C. Optional flexible structures  28  may be used to support display cover layer portion  24 B. Structures  28  may include opaque masking layer structures. For example, structures  28  may include a layer of black ink on the underside of display cover layer portion  24 B to hide internal components from view. 
     Materials such as glass, hard plastic, and other hard transparent materials may be used in forming rigid portions  24 A and  24 C of display cover layer  24 . To ensure that portion  24 B of display cover layer  24  in region  14 B of display  14  is sufficiently flexible to accommodate bending about bend axis  22 , portions of display cover layer  24  may be selectively removed from portion  24 B to form recessed areas. By creating one or more recesses in portion  24 B (relative to portions  24 A and  24 C), the flexibility of display cover layer  24  in region  14 B of display  14  may be enhanced. In the illustrative configuration of  FIG. 8 , display cover layer  24  has been provided with grooves  30  in area  14 B. Grooves  30  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  30  may have widths X 1  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). The width W of display  14  may be 0.5-1000 cm, may be 1-300 cm, 1-100 cm, 1-20 cm, or other suitable width. Grooves  30  may span all of width W or may span a subset of width W. The width GW of flexible portion  24 B of display cover layer  24  may be 10-1000 microns, may be more than 50 microns, may be more than 0.5 mm, may be more than 5 mm, may be 0.01-1 cm, may be less than 5 cm, may be less than 5 mm, may be less than 1 mm, may be 0.1-20 mm, or may be any other suitable width. The thickness T of display cover layer  24  may be 100 microns, 50-150 microns, more than 20 microns, less than 1000 microns, 20-500 microns, or other suitable thickness. The thickness T′ of the portion of display cover layer  24  between the bottoms of grooves  30  and outer surface  31  of display cover layer  24  may be 50 microns, may be 100 microns, 50-150 microns, more than 20 microns, less than 1000 microns, less than 200 microns, less than 70 microns, less than 60 microns, 20-500 microns, or other suitable thickness. Relatively small thicknesses (e.g., 40-60 microns or less) may help enhance the flexibility of portion  24 B of display cover layer  24 . There may be 1-10,000 grooves  30  in portion  24 B, more than 100 grooves  30  in portion  24 B, fewer than 5000 grooves  30  in portion  24 B, 50-3000 grooves  30  in portion  24 B, more than 500 grooves  30  in portion  24 B, more than 1000 grooves  30  in portion  24 B, fewer than 8000 grooves  30  in portion  24 B, or any other suitable number of grooves  30  in portion  24 B. In general, any suitable dimensions may be used for the structures of display cover layer  24 . The use of parallel grooves with rectangular cross-sectional shapes that run across the width of display  14  is merely illustrative. 
     Grooves  30  may have any suitable shapes. As shown in the cross-sectional side view of grooves  30  of  FIG. 9 , grooves  30  may have a semicircular shape or other shape with curved sidewall surfaces. Grooves  30  of  FIG. 10  have trapezoidal shapes. If desired, grooves  30  may have rectangular shapes with curved corners as shown in  FIG. 11 . Other cross-sectional shapes may be used for grooves  30  if desired. The illustrative groove profiles of  FIGS. 8, 9, 10, and 11  are merely illustrative. 
       FIG. 12  shows how grooves  30  may be filled with a polymer or other flexible substance. Filler  32  may be, for example, a clear elastomeric polymer such as silicone to permit viewing of overlapped display structures or may be formed from an opaque polymer. Other filler materials may be used, if desired. In configurations in which filler  32  is transparent, filler  32  may have an index of refraction that matches the index of refraction of the display cover layer. For example, display cover layer portion  24 B may have an index of refraction of 1.5 and filler  32  may be formed form a polymer with a matched index of refraction of 1.5 (or 1.4-1.6 or other suitable value close to 1.5). Filler  32  may help support portion  24 B to prevent cracking. If desired, filler  32  may cover surfaces  34  of portion  24 B, as shown in  FIG. 13 . 
       FIG. 14  is a cross-sectional side view of portion  24 B of display cover layer  24  in an illustrative configuration in which portion  24 B has been thinned relative to portions  24 A and  24 B (effectively forming a single wide recess such as recess  30 W). Recess  30 W may be filled with filler  32  to help support portion  24 B.  FIG. 15  shows how portion  24 B may bend about bend axis  22 . 
     The outer surface of display cover layer  24  may be covered with antireflection layers, antismudge layers, scratch resistance coatings, and other layers. As shown in  FIG. 16 , for example, flexible portion  24 B of display cover layer  24  may have a flexible portion such as portion  24 B- 1  that is covered with a harder and more scratch resistant layer such as hard coating layer  24 B- 2 . Layer  24 B- 2  may be formed form one or more inorganic layers such as silicon nitride, silicon oxide, etc. The thickness of layer  24 B- 2  and other coating layers in device  10  may be about 0.1-0.5 microns, less than 1 micron, more than 0.15 microns, or other suitable thickness. 
     As shown in the illustrative configuration of display cover layer  24  in  FIG. 17 , a hard coating layer (or other surface coating) may extend over portions  24 A,  24 B, and  24 C of display cover layer  24 . For example, portion  24 A may have rigid layer  24 A- 1  that is covered with hard coating layer  24 A- 2 . Portion  24 C may have rigid layer  24 C- 1  that is covered with hard coating layer  24 C- 2 . Flexible portion  24 B of layer  24  may have flexible layer  24 B- 1  (e.g., flexible polymer, glass with grooves or other recesses, etc.) that is covered with hard coating layer  24 B- 2 .  FIG. 18  shows how a portion of display cover layer  24  such as flexible display cover layer  24 B (having grooves  30  or other recesses) may be covered with hard coating layer  24 B- 2 . This hard coating may be separate from the coatings on portions  24 A and  24 C or coating layer  24 B- 2  of  FIG. 18  may extend over the entire surface of display cover layer  24 . 
     As shown in  FIG. 19 , grooves  30  need not be straight. In the  FIG. 19  example, most of grooves  30  extend parallel to bend axis  22 , but portions of grooves  30  of  FIG. 19  meander away from axis  22 .  FIG. 20  shows how grooves  30  or other recesses in display cover layer  24 B may have pseudorandom patterns to help prevent optical interference effects from creating visible artifacts on display  14 . In the example of  FIG. 21 , grooves  30  have an elongated shape that extends along 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. 22  is a diagram of display cover layer portion  24 B in an illustrative configuration in which grooves  30  accommodate deformation along multiple axes. In particular, grooves  30  form concentric rings that allow portion  24 B to deform into the shape of a dome.  FIG. 23  shows how grooves  30  may be formed in a hexagonal matrix separating hexagonal islands formed by unrecessed areas of portion  24 B. In the example of  FIG. 24 , grooves  30  are formed between rectangular strip-shaped islands in portion  24 B and run parallel to bend axis  22 .  FIG. 25  shows how grooves  30  may be formed between circular dots or dots of other shapes that are not recessed.  FIG. 26  shows how circular recessed portions (recesses  30 ) may be formed in portion  24 B. Other patterns of recesses  30  may be provided in display layers such as display cover layer  24 B or other layers of material in display  14  and/or housing  12  to enhance flexibility about bend axis  22 , if desired. 
     In the example of  FIG. 27 , flexible portion  24 B has been provided with a thinned portion such as wide groove  30  with a curved inner surface such as surface  38 . Support member  35  may be used to support portion  24 B. Member  35  may be formed from a sheet of metal, plastic, fiber composites, glass, other materials, or combinations of these materials. Foam  41  or other elastomeric material, mechanical biasing structures, or additional support structures in device  10  may be used to help hold member  35  in place against surface  38 . Support member  35  may slide along inner surface  38  in directions  36  as display cover layer  24  is flexed about bend axis  22 . 
       FIG. 28  is a cross-sectional side view of display cover layer  24  in an illustrative configuration in which display cover layer portion  24 B includes multiple layers of material. In the  FIG. 28  example, display cover layer  24  has outer layer  24 BT and inner layer  24 BB. The outer layer may be attached to the inner layer using adhesive  42  in rigid display cover layer portions  24 A and  24 B. In flexible display cover layer portion  24 B, adhesive  42  may be omitted. This allows outer layer  24 BT and inner layer  24 BB to move relative to each other during bending about bend axis  22  (e.g., to form gap  40 , to slide relative to each other, etc.). Adhesive  42  may be formed from an elastomeric material that permits lateral movement between the different layers making up display cover layer  24  during bending. The illustrative configuration of  FIG. 28  includes two separate display cover layer, but three or more layers may be used in forming display cover layer  24 , if desired. 
     As shown in  FIG. 29 , there may be gaps between the layers of a multi-layer display cover layer or other display layer. Display cover layer  24  of  FIG. 29  has multiple layers such as layers  24 L (e.g., layers of glass, plastic, sapphire, fiber-composite material, other materials, and/or combinations of these materials). Each of layers  24 L may be sufficiently thin to facilitate bending (e.g., the thickness of each of layers  24 L may be less than 100 microns, less than 75 microns, less than 50 microns, more than 10 microns, or other suitable thickness. In rigid display cover layer portions  24 A and  24 C, layers  24 L may be attached to each other using intervening layers of adhesive (as an example). In flexible display cover layer portion  24 B, layers  24 L may include solid layers such as layers  24 B′ that are integral portions of layers  24 L (e.g., glass, plastic, etc.) and intervening layers that have openings filled with material  24 B″ to facilitate bending. Material  24 B″ may be a compressible fluid such as air, nitrogen, or other gas, may be a polymer (e.g., an elastomeric polymer having an index of refraction that matches the index of refraction of layers  24 L), may be an incompressible fluid such as water, oil, or other liquid (e.g., oil having an index of refraction matching the index of refraction of layers  24 L), or may be any other suitable material that facilitates bending of portion  24 B of layer  24 . In configurations in which material  24 B″ is a liquid or gas, layer  24  may be provided with an excess fluid (liquid or gas) reservoir. The reservoir may have an elastomeric wall such as wall  48  forming a cavity  50  that expands to receive excess gas or liquid  24 B″ through passageways  46  through layers  24 L when layer  24  is bent about bend axis  22  (which thins the gaps between layers  24 L in flexible area  14 B and thereby forces liquid  24 B″ into cavity  50 ). 
       FIG. 30  is a cross-sectional side view of an illustrative flexible structure of the type that may be used in forming hinge  20  of  FIG. 1  and/or flexible display cover layer portion  24 B or other flexible portions of device  10  to permit bending of device  10  about axis  22 . Structures  52  of  FIG. 30  may be rigid structures of metal, glass, plastic, fiber-composite material, sapphire, or other material (e.g., structures  52  may form display layers  24 A and  24 B in a display cover layer, housing walls, internal hinge structure layers, or other rigid layers for areas  14 A and  14 C). In area  14 B of device  10 , an opening (opening  56 ) may be formed in layers  52  to facilitate bending. Thin sheets of plastic or metal or other hinging members such as flexible layers  54 T and  54 B may be formed above and below opening  56  (e.g., flush with the outer and inner surfaces of structures  52 . Layers  54 T and  54 B may be formed from polymer, metal, glass that is sufficiently thin to bend (e.g., glass with grooves), or other suitable materials. Opening  56  may be filled with air, oil, elastomeric polymer (solid or foam), etc. 
     One or more additional layers such as layer  58  may be attached under the surface of the structures of  FIG. 30 . Layer  58  may be, for example, a flexible display panel in configurations in which the structures of  FIG. 30  such as layers  52  and  54 T and  54 B are transparent or may be any other suitable component for device  10  (e.g., a touch sensor layer, a structural support layer, etc.).  FIG. 31  shows how inner layer  54 B may bow outward and may contact (or nearly contact) the inner surface of outer layer  54 T when the structures of  FIG. 30  are bend about axis  22 . In configurations in which layers  54 T and  54 B are formed from a springy material (e.g., metal or springy plastic), the hinge formed from layers  54 T and  54 B may exhibit a toggle effect when device  10  opens and closes. 
     In the example of  FIG. 32 , structures  52  have been sandwiched between outer and inner layers  60  in rigid areas  14 A and  14 C. In region  14 B, layers  60  may merge to form a single layer of material or may be separate (e.g., separate layers such as layers  54 T and  54 B of  FIGS. 30 and 31 ). Layers  60  are sufficiently thin to be flexible in region  14 B. Layers  60  may be formed from glass, plastic, metal, or other suitable materials. Layers  60  may be transparent when layers  60  overlap pixels in a display and may be opaque when layers  60  form a hinge that does not lie on top of any pixels. If desired, edge  62  of structures  52  may be eased (e.g., progressively thinned at increasing distances towards the edges of structures  52 ) as shown in  FIG. 33  to help reduce stresses in layers  60  when bent about bend axis  22 . 
       FIG. 34  is a cross-sectional side view of an illustrative multilayer flexible structure for device  10 . The flexible structure of  FIG. 34  may form part of a display cover layer such as flexible portion  24 B, a hinge such as hinge  20  of  FIG. 1 , a flexible housing wall or internal housing structure, or other flexible layer in device  10 . Layers  64 T and  64 B may be rigid planar layers of material (glass, plastic, metal, etc.). Layers  62 T,  62 M, and  62 B may be formed from thin flexible glass layers, polymer layers, metal layers, or layers of other material. Layer  64 T may be sandwiched between outer layer  62 T and middle layer  62 M. Layer  64 B may be sandwiched between middle layer  62 M and inner layer  62 B. Layers such as layers  62 M and  62 B may bow outwards towards layer  62 T when the structures of  FIG. 34  are bent. There may be additional layers in the structures of  FIG. 34  if desired. The configuration of  FIG. 34  is merely illustrative. 
     Layer  64 T may have an opening such as opening  66 T to enhance flexibility in flexible area  14 B. Layer  64 B may have an opening such as opening  66 B to enhance flexibility in flexible area  14 B. Openings  66 T and  66 B may be filled with flexible materials such as air, other gasses, liquids (e.g., index-matched oil), flexible polymer (foam, solid materials such as solid silicone layers), etc. 
       FIG. 35  is a cross-sectional side view of an illustrative multilayer flexible structure for device  10  having a layer that can slide within a rigid support structure. The flexible structure of  FIG. 35  may be a display cover layer such as flexible portion  24 B, a hinge such as hinge  20  of  FIG. 1 , a flexible housing wall or internal housing structure, or other flexible layer in device  10 . Layer  68  may be a rigid planar layer of material (glass, plastic, metal, etc.). Flexible layers  70 T and  70 B may span opening  76  in layer  68  in flexible area  14 B and may be formed on opposing sides of opening  76 . Layers  70 T and  70 B may be mounted so as to be flush with the opposing inner and outer surfaces of layer  68 . Layers  70 T and  70 B may each be formed from a single layer of material or may, as shown in  FIG. 35 , each include multiple sublayers  72  (e.g., thin layers of glass, plastic, metal, or other flexible layers of material). Adhesive  74  may attach layers  74  to each other and to layer  68 . If desired, some portions of layers  74  (e.g., the left edge of lower layer  70 B in the example of  FIG. 35 ) may be left unattached to layer  68  (and if desired, unattached to each other). These unattached portions of layer  70 B may permit stress-relieving sliding motions to take place between layer  70 B and layer  68  (and between sublayers  72 ) when bending the structures of  FIG. 35  in directions  84  about bend axis  22 . Opening  76  may be filled with air, liquid or polymer (e.g., index matching liquid or polymer in scenarios in which layers  70 T and  70 B are transparent), or other suitable materials. 
     Layer  68  may have a slot such as slot  78 . Left edge  80 A of layer  70 B (in the example of  FIG. 35 ) is not attached to layer  68  with adhesive  74 , so edge  80 A may move into slot  78  in direction  82  to position  80 B when the structures of  FIG. 35  are bent about bend axis  22  in directions  84 . 
     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: 20200310
Publication Date: 20201117
Grant Date: 20201117
Priority Date: 20150730
Inventors: AI, JIANG
UTTERMANN, ERIK A.
KIM, SOYOUNG
Assignee: APPLE INC
CPC Classifications: [{"code": "H01L2251/5338", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01L51/524", "inventive": true, "first": true, "tree": "[]"}, {"code": "H10K50/841", "inventive": true, "first": true, "tree": "[]"}, {"code": "H10K2102/311", "inventive": false, "first": false, "tree": "[]"}, {"code": "H10K2102/311", "inventive": false, "first": false, "tree": "[]"}, {"code": "H10K59/871", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 62749632