Electronic device with curved display

Abstract

An electronic device display can have pixels formed from crystalline semiconductor light emitting diode dies, organic light emitting diodes, or other pixel structures. These pixels can be formed in a display panel having a single substrate or an array of display panel tiles (24). The display panel has inward-facing display panel contacts (56') that mate with corresponding outward-facing interconnect substrate contacts (54) on an interconnect substrate (44). The interconnect substrate can have a region of compound curvature overlapped by the display panel. To enhance the flexibility of the interconnect substrate, the interconnect substrate can have flexibility enhancing openings, and / or can be formed from a material having a low modulus of elasticity, such as silicone or other elastomeric material.

Description

[0001] This application claims priority to U.S. Patent Application No. 17 / 178,556, filed February 18, 2021, and U.S. Provisional Patent Application No. 63 / 007,845, filed April 9, 2020, which are hereby incorporated by reference in their entirety. TECHNICAL FIELD

[0002] The present disclosure relates generally to electronic devices, and more particularly to electronic devices having displays. BACKGROUND

[0003] Electronic devices often have displays. The displays can have active areas with pixels that display images for users, and inactive borders. The displays can have flat surfaces and surfaces with curvature.

[0004] Forming displays for electronic devices can be challenging. When forming displays with surface curvature, if not attended to, display performance can be adversely affected. There can also be a risk that the inactive border area of the display can be too large and unattractive. SUMMARY

[0005] Electronic device displays can have display panels mounted to a separate interconnect substrate. The interconnect substrate can include interconnects that help route signals to the display panel without the need for an undesirably large inactive display border that includes signal routing lines. The display panel can be formed from a single substrate layer, or can include a set of display panel tiles that cover the interconnect substrate. The interconnect substrate can be flexible, and can be curved to a surface such as a surface area that exhibits compound curvature. This allows the display to have a curved surface area.

[0006] The interconnect substrate can have outward facing contacts that are electrically shorted to corresponding inward facing display panel contacts. The interconnect substrate can have interconnects that help route signals for the display panel. Integrated circuits can be mounted to the inward facing interconnect substrate contacts, can be embedded in the interconnect substrate, and / or can be embedded in the display panel, if desired.

[0007] The interconnect substrate can be flexible enough to allow the surface of the interconnect substrate to exhibit compound curvature when mounted on a support structure of compound curvature and / or when mounted against an inner surface of a display cover layer that has compound curvature. To enhance the flexibility of the interconnect substrate, and thereby help avoid wrinkling and / or buckling of the interconnect substrate, the interconnect substrate can have flexibility enhancing openings and / or can be formed from a material with a low modulus of elasticity such as silicone or other elastomeric material. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 is a schematic diagram of an illustrative electronic device according to one embodiment.

[0009] Figure 2 Perspective view of an exemplary electronic device with a display according to an embodiment.

[0010] Figure 3 Cross-sectional side view of exemplary layers of a display according to an embodiment, showing how the layers can have surface curvature.

[0011] Figure 4 Cross-sectional side view of an exemplary display according to an embodiment.

[0012] Figure 5 Cross-sectional side view of an exemplary portion of a display according to an embodiment in which display panel layers are mounted to an interconnect substrate.

[0013] Figure 6 Top view of an exemplary display layer with slit-shaped (slot-shaped) openings according to an embodiment.

[0014] Figure 7 Top view of an exemplary display layer with grid-shaped openings according to an embodiment.

[0015] Figure 8 Top view of an exemplary mesh-shaped display layer with openings forming an array of islands interconnected to a meandering strip according to an embodiment.

[0016] Figure 9 , Figure 10 , Figure 11 , Figure 12 and Figure 13 Exemplary display layer according to an embodiment.

[0017] Figure 14 and Figure 15 Top views of exemplary tiling patterns that can be used for display panels according to embodiments.

[0018] Figure 16 Top view of an exemplary flexible interconnect substrate according to an embodiment, having slots and an array of contacts oriented at a non-zero angle relative to the horizontal plane to compensate for the expected rotation of the contacts when the flexible interconnect substrate is stretched into place in a display.

[0019] Figure 17 Top view of an exemplary flexible interconnect substrate of Figure 16 after stretching according to an embodiment.

[0020] Figure 18 , Figure 19 and Figure 20This is a diagram illustrating how a display layer, according to one embodiment, can have regions with different rigidities.

[0021] Figure 21 and Figure 22 This is a top view of an exemplary display according to one embodiment, showing an area in which the display layer can be flexibly and selectively varied.

[0022] Figure 23 This is a cross-sectional side view of an exemplary display having rigid display panel patches mounted on a flexible interconnect substrate, according to one embodiment.

[0023] Figure 24 This is a side view of an exemplary device for forming a display from layers having surface curvature, according to one embodiment. Detailed Implementation

[0024] Electronic devices may be equipped with a display. The display can be used to show images to a user. The display may be formed from an array of light-emitting diode pixels or other pixels. For example, the device may have an organic light-emitting diode display or a display formed from an array of micro light-emitting diodes (e.g., diodes formed from crystalline semiconductor dies).

[0025] Figure 1 A schematic diagram of an exemplary electronic device with a display is shown. Device 10 may be a cellular phone, tablet computer, laptop computer, wristwatch or other wearable device, television, stand-alone computer monitor or other monitor, computer monitor with an embedded computer (e.g., desktop computer), system embedded in a vehicle, multimedia terminal or other embedded electronic device, media player or other electronic equipment. Configurations where device 10 is a wristwatch, cellular phone or other portable electronic device may sometimes be described herein as examples. This is exemplary. In general, device 10 may be any suitable electronic device with a display.

[0026] Device 10 may include control circuitry 20. Control circuitry 20 may include storage and processing circuitry for supporting the operation of device 10. This storage and processing circuitry may include storage devices such as non-volatile 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. The processing circuitry in control circuitry 20 may be used to acquire input from sensors and other input devices, and may be used to control output devices. The processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, baseband processors and other wireless communication circuits, power management units, audio chips, application-specific integrated circuits, etc. During operation, control circuitry 20 may use displays and other output devices to provide visual output and other outputs to the user.

[0027] To support communication between device 10 and external equipment, control circuitry 20 can use communication circuitry 22 to communicate. Circuitry 22 can include antennas, radio-frequency transceiver circuitry (wireless transceiver circuitry), and other wireless communication circuitry and / or wired communication circuitry. Circuitry 22, which can sometimes be referred to as control circuitry and / or control and communication circuitry, can support bidirectional wireless communication between device 10 and external devices via wireless links (e.g., circuitry 22 can include radio-frequency transceiver circuitry such as wireless local area network transceiver circuitry configured to support communication via a wireless local area network link, near-field communication transceiver circuitry configured to support communication via a near-field communication link, cellular telephone transceiver circuitry configured to support communication via a cellular telephone link, or transceiver circuitry configured to support communication via any other appropriate wired or wireless communication link). For example, wireless communication can be supported via a Bluetooth® link, a Wi-Fi® link, a wireless link operating at frequencies between 10 GHz and 400 GHz, a 60 GHz link or other millimeter wave link, a cellular telephone link, or other wireless communication link. Device 10, if desired, can include power supply circuitry for transmitting and / or receiving wired and / or wireless power, and can include a battery or other energy storage device. For example, device 10 can include a coil and a rectifier to receive wireless power provided to circuitry in device 10.

[0028] Device 10 can include input-output devices such as device 24. Input-output device 24 can be used to gather user input, to gather information about a user’s surroundings, and / or to provide output to a user. Device 24 can include one or more displays such as display 14. Display 14 can be an organic light-emitting diode display, a liquid crystal display, an electrophoretic display, an electro wetting display, a plasma display, a microelectromechanical systems display, a display having an array of pixels formed from crystalline semiconductor light-emitting diode dies (sometimes referred to as micro-LEDs), and / or other displays. Configurations in which display 14 is an organic light-emitting diode display or a micro-LED display are sometimes described herein by way of example.

[0029] Display 14 can have an array of pixels configured to display images to a user. Pixels can be formed on a display panel formed from a rigid and / or flexible display panel substrate. One or more additional substrates, which can sometimes be referred to as interconnect substrates, can include interconnects (signal paths) for distributing power signals and other signals to the display panel. In an illustrative configuration, one or more display panels can be mounted to a flexible interconnect substrate such that display panel contacts mate with corresponding interconnect substrate contacts, thereby electrically connecting the interconnects of the display panel to the interconnects of the interconnect substrate. The flexibility of the interconnect substrate allows the interconnect substrate to accommodate a curved display surface.​

[0030] The sensors 16 in the input-output devices 24 can 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., two-dimensional capacitive touch sensors integrated into the display 14, two-dimensional capacitive touch sensors that overlap the display 14, and / or touch sensors that form buttons, trackpads, or other input devices that are not associated with the display), and other sensors. If desired, the sensors 16 can include optical sensors such as optical sensors that emit and detect light, ultrasonic sensors, optical touch sensors, optical proximity sensors, and / or other touch and / or proximity sensors, monochrome and color ambient light sensors, image sensors, fingerprint sensors, temperature sensors, sensors for measuring three-dimensional contactless gestures ("air gestures"), pressure sensors, sensors for detecting position, orientation, and / or motion (e.g., accelerometers, magnetic sensors such as compass sensors, gyroscopes, and / or inertial measurement units that contain some or all of these sensors), health sensors, radio frequency sensors, depth sensors (e.g., structured light sensors and / or depth sensors based on stereoscopic imaging devices that capture three-dimensional images), optical sensors such as self-mixing sensors and light detection and ranging (lidar) sensors that collect time-of-flight measurements, humidity sensors, moisture sensors, line-of-sight tracking sensors, and / or other sensors. In some arrangements, the device 10 can use the sensors 16 and / or other input-output devices to gather user input. For example, buttons can be used to gather button press input, touch sensors that overlap the display can be used to gather user touch screen input, touchpads can be used to gather touch input, microphones can be used to gather audio input, accelerometers can be used to monitor when a finger contacts an input surface and thus can be used to gather finger press input, and so on.

[0031] If desired, the electronic device 10 can include additional components (see, e.g., other devices 18 in the input-output devices 24). The additional components can include haptic output devices, audio output devices such as speakers, light-emitting diodes for status indicators, light sources such as light-emitting diodes that illuminate portions of the housing and / or display structure, other optical output devices, and / or other circuitry for gathering input and / or providing output. The device 10 can also include a battery or other energy storage device, connector ports for supporting wired communication with auxiliary equipment and for receiving wired power, and other circuitry.

[0032] Figure 2 is a perspective view of the electronic device 10 in an illustrative configuration in which the device 10 is a wearable device such as a wrist watch. As Figure 2As shown, device 10 can have a band such as band 26 and a main unit such as main unit 28 coupled to band 26. Display 14 can cover part or all of the front face of main unit 28. Touch sensor circuitry such as two-dimensional capacitive touch sensor circuitry can be incorporated into display 14. Band 26 (which can sometimes be referred to as a strap, wristband, watchband, wrist strap, or watch strap) can be used to secure main unit 28 to a user's wrist.

[0033] Main unit 28 can have a housing such as housing 12. Housing 12 can form front and rear housing walls, sidewall structures, and / or internal support structures (e.g., a frame, an interposer member, etc.) of main unit 28. Glass structures, transparent polymer structures, image transmission layer structures (e.g., coherent fiber bundles forming a fiber optic plate that can act as a display cover layer and / or part of a display cover layer), and / or other transparent structures covering display 14 and other parts of device 10 can provide structural support for device 10 and can sometimes be referred to as a housing structure or a display cover layer structure. For example, a transparent housing portion such as a glass or polymer housing structure covering and protecting a pixel array in display 14 can act as a display cover layer for the pixel array while also acting as a housing wall on the front face of device 10. Portions of housing 12 on the sidewalls and rear wall of device 10 can be formed from transparent structures and / or non-transparent structures.

[0034] Figure 2 Device 10 of FIG. 1 has a rectangular profile (rectangular perimeter) with four rounded corners (e.g., the front face of device 10 can be square). If desired, device 10 can have other shapes (e.g., a circular shape, a rectangular shape with edges of unequal lengths, and / or other shapes). Figure 2 The configuration of FIG. 1 is illustrative.

[0035] If desired, openings can be formed in the surfaces of device 10. For example, openings can be formed to accommodate speakers, cable connectors, microphones, buttons, and / or other components. Openings such as connector openings can be omitted when wireless reception of power is used or when data is transmitted and received wirelessly using wireless communication circuitry in circuitry 22 or through contacts flush with the outer surfaces of device 10.

[0036] It can be desirable to minimize the borders of display 14. This can be accomplished by using through-holes to attach the pixel array to one or more underlying interconnect substrates, and / or by bending a flexible display panel substrate out of the plane of the pixel array.

[0037] Device 10 can have surfaces that are flat and / or have curved cross-sectional profiles. For example, display 14 can include one or more layers that have flat and / or curved portions. These display layers can include cover layers, display panel layers that contain pixels, interconnect substrate layers, adhesive layers, touch sensor layers, etc. Figure 3 Exemplary display layers are shown in FIGS. 1A-1C. As shown in FIG. 1A, display layer 30 can include a flat surface 34 and a curved surface 32. As shown in FIG. IB, display layer 30 can include a flat surface 34 and a curved surface 32 that has a curved cross-sectional profile. As shown in FIG. 1C, display layer 30 can include a flat surface 34 and a curved surface 32 that has a curved cross-sectional profile. Figure 3 As shown in the perspective view of FIG. 2, display layers in display 14, such as exemplary display layer 30, can have flat surfaces such as flat surface 34 and curved surfaces such as curved surface 32. Curved surfaces have curved cross-sectional profiles.

[0038] Display layers can feature curved surfaces that can be made planar without distortion (sometimes referred to as malleable surfaces). For example, the center of a straight edge of a display layer that has a rectangular outline and rounded corners can feature a malleable surface. Display layers can also have regions of complex curvature surfaces (e.g., surfaces that can only be made planar with distortion, sometimes referred to as surfaces with Gaussian curvature). As one example, the rounded surface region in a rounded corner of a rectangular display that has straight edges and rounded corners can have complex curvature (see, e.g., surface 32 of FIG. 3). As another example, a circular display layer can have a flat circular central region, and this central region can be surrounded by a circular ring-shaped region that has complex curvature (e.g., the edge portions of the circular display layer can slope downward from the flat central region). Figure 3

[0039] Challenges arise in forming display layers for displays that have curved surfaces such as regions of complex curvature. If not attended to, the display layers will exhibit undesirable levels of stress or will wrinkle.

[0040] ​To avoid these problems, the display 14 can be provided with thin base layers that have grooves and / or through-hole openings to facilitate bending, and / or that are formed of an elastomeric material such as silicone or other polymer that has a relatively low modulus of elasticity. To ensure that a desired density of pixels is visible on the front side of the display 14, different approaches can be taken to form different display layers. As one example, a first display layer at the top of the display, such as a display panel base on which the pixels of the display are formed, can be formed of a first type of structure (e.g., rigid tiles), while a second display layer at the bottom of the display, such as an interconnect base on which the display panel tiles are mounted, can be formed of an elastic mesh. The display panel tiles can have any suitable lateral dimensions XI and Yl (e.g., XI and / or Yl can have a value of at least 10 microns, at least 20 microns, 10 to 60 microns, at least 100 microns, less than 1000 microns, less than 500 microns, less than 200 microns, less than 100 microns, etc.). Each tile can include an array of pixels. Other configurations in which different types of structures are used to form the upper and lower bases in the display 14 can be used if desired.

[0041] Figure 4 is a cross-sectional side view of a portion of an illustrative display that includes a display layer having a curved cross-sectional profile (e.g., a display having a compound curvature region and / or other curved surface region). In Figure 4 In the example of FIG. 4A, the display 14 includes a display panel 14P on an inward-facing surface of a display cover layer 40, an optional adhesive layer 42, and an interconnect base 44. The display cover layer 40 (e.g., a layer of optically transmissive polymer, glass, sapphire, etc.) can overlap the panel 14P, adhesive layer 42, and base 44. The outer and inner surfaces of the layer 40 can have a compound curvature region (as one example).

[0042] To mitigate shear stresses that can otherwise tend to build up as the layers of the display 14 are bent to form a curved surface, the adhesive layer 42 (if desired) can be formed of an elastomeric polymer that is able to deform (e.g., shear) as portions of the layers 14P and 44 slide past one another. Stress can also be reduced by forming the base 44 from a silicone or other elastomeric material that has a low modulus of elasticity (e.g., an elasticity of less than 10 Gpa, less than 2 Gpa, less than 0.4 Gpa, less than 0.1 GPa, less than 0.01, at least 0.001, etc.). The base 44 can include grooves and / or through-holes that help to enhance flexibility.

[0043] Panel 14P can also be formed of an elastomeric structure and / or a structure with grooves or other openings, or, if desired, can be formed using spliced ​​rigid substrates (e.g., patches formed of a substrate material having an elastic modulus of 0.1-10 GPa, at least 1 GPa, at least 10 GPa, at least 100 GPa, etc.). In this case, the interconnecting substrate 44 may be provided with large openings or other potentially unsightly structures to facilitate bending without making these structures visible to the user of device 10 (because the pixels of the overlapping display panel patches in panel 14P cover these potentially unsightly structures and block them from view). If desired, the materials used to form panel 14P, adhesive layer 42, and substrate 44 can be different from each other. For example, panel 14P can be formed of a substrate material such as polyimide or fiberglass-filled epoxy resin, substrate 44 can be formed of a soft elastomeric material such as silicone resin, and adhesive layer 42 can be formed of one of these materials (e.g., silicone resin to adapt to shearing), or of a different material (e.g., acrylic resin).

[0044] Figure 5 The image shows a cross-sectional side view of a display with stacked display layers (such as these layers). Figure 5 As shown, the display 14 may include a display panel 14P and an interconnect substrate 44. The display panel 14P may be formed on an outward-facing surface of the substrate 44 (e.g., a surface facing away from the interior of the housing 12). The display panel 14P may have an array of pixels P. Pixels P may be thin-film organic light-emitting diodes, light-emitting diodes formed from crystalline semiconductor dies, and / or other pixels. Panel 14P may be a single non-fractured layer, or may be divided into separate smaller panels (display panel patches). When divided into display panel patches, each patch may contain an N×N pixel P array. The value of M may be at least 1, at least 5, at least 10, at least 16, at least 32, at least 100, less than 250, less than 75, less than 25, or less than 17 (as an example). The display panel 14P may have a substrate formed of one or more dielectric layers, such as substrate 46. The layers forming substrate 46 may be flexible printed circuit layers, such as polyimide layers, rigid printed circuit board material layers (such as fiberglass-filled epoxy resin (e.g., FR4)), and / or other polymer (or other dielectric) layers.

[0045] Signal lines can be formed in the substrate 46. These lines (sometimes referred to as interconnects) can be formed by metal-filled through-holes and other metal traces 48. Some of the metal traces 48 can form contacts of the panel 14P (see, for example, inward-facing display panel contacts 48C). Electronic components, such as... Figure 5Electronic components 50, such as component 50, can optionally be embedded in the substrate 46. Interconnects formed from the metal traces 48 can route signals between the pixels P, components such as component 50, and / or other circuitry embedded in the substrate 46, and / or the contacts 48C. Components such as component 50 can include integrated circuits (e.g., display integrated circuits that receive image data from the interconnects of the interconnect substrate 44 and route the image data to a corresponding set of nearby pixels (e.g., an NxN array of pixels P), such as pixel control circuitry or other display integrated circuits). If desired, sensors 16 can be included in the display panel 14P and / or the substrate 44. For example, component 50 (or a set of components 50) can form one of the sensors 16, such as a touch sensor, a fingerprint sensor, a force sensor, or other sensor, and / or the sensors 16 can be formed from thin film circuitry in the substrate 46, such as the metal traces 48, and other thin film structures in the substrate 46 (e.g., thin film transistors, etc.).

[0046] The contacts 48C of the display panel 14P can mate with corresponding outward-facing interconnect substrate contacts 52C in the interconnect substrate 44. The interconnect substrate 44 can have one or more dielectric layers of substrate material 54 formed. These dielectric layers can be formed from silicone, other elastomeric materials, or other flexible polymers. Metal traces 52 can form signal paths (interconnects) in the substrate 44 that carry signals between the contacts and internal circuitry such as components 56 of the substrate 44. These interconnects can include the contacts 52C and signal lines for routing power signals, data signals, and / or other signals to and / or from the display panel 14P. As with the optional components 50 of the display panel 14P, the interconnect substrate 44 can optionally include one or more embedded electronic components such as components 56 (e.g., integrated circuits, sensors 16, etc.).

[0047] Outward-facing interconnect substrate contacts such as contacts 52C on the lower (inward-facing) surface of the substrate 44 can receive external components such as external component 60. Components such as component 60 can include board-to-board connectors or other electrical connectors (e.g., to mate with corresponding logic board connectors), and / or can include integrated circuits (e.g., display driver integrated circuits, sensors 16, etc.). As shown, the component 60 can include contacts 62 that mate with corresponding contacts 52C of the substrate 44. Conductive material 58 can be used to help form electrical connections between the connectors 48C and the respective connectors 52C, and between the connectors 62 and the corresponding connectors 52C. The conductive material 58 can include solder, anisotropic conductive adhesive, or other conductive material. If desired, other techniques such as thermal compression bonding or surface activation bonding can be used to form electrical connections between mating contacts. Figure 5

[0048] Using Figure 5 ​With the type of arrangement shown, image data can be supplied to the substrate 44 from a display driver integrated circuit or other integrated circuit mounted to the lower surface of the substrate 44 (e.g., component 60), and / or can be supplied to the substrate 44 using a flexible printed circuit bus coupled to the connectors on the contacts 52C (e.g., in a configuration in which the component 60 is a connector). The image data can then be routed to the contacts 48C of the display panel 14P via the interconnects 52 and the outward-facing contacts 52C. The image data can be routed from the contacts 48C to the pixels P using the interconnects 48 and optional embedded circuitry such as the component 50.

[0049] In an illustrative configuration in which the panel 14P has a tiled arrangement, each tile can have a respective optional embedded component 50 (e.g., circuitry to supply image data to a group of associated pixels P). If desired, some of the pixels P can be replaced by sensor electrodes (e.g., capacitive sensor electrodes for a capacitive touch sensor), light detectors such as photodiodes, and / or other sensors 16 (e.g., the display 14 can be a touch-sensitive display, and / or can include other sensor circuitry such as fingerprint sensing circuitry, force sensors, etc.). Sensor data from sensors on the surface of the panel 14P, sensors embedded in the panel 14P, and / or sensors mounted on or embedded in the substrate 44 can be routed through the interconnects of the panel 14P and / or the substrate 44 to control circuitry in the device 10.

[0050] To facilitate the ability of the display 14 to conform to compound curvature surfaces and other curved surfaces, one or more layers of the display 14 can be provided with recesses and / or through-hole openings to enhance flexibility. Such openings can include slotted openings such as the illustrative slotted opening 64 in a display layer DL of Figure 6 , grid-shaped openings such as the opening 64 in Figure 7 , and / or openings such as the opening 64 that create a mesh shape for the display layer DL of Figure 8 . The openings 64 can be configured (by selecting the opening size, shape, layer penetration, density, and / or other attributes) to ensure that the layer DL exhibits enhanced flexibility (e.g., the layer DL with the flexibility-enhancing openings 64 will be at least 10%, at least 50%, or other suitable amount more flexible than the layer DL without any openings 64, and the ability of the layer DL to exhibit compound surface curvature regions will likewise be enhanced).

[0051] In the example of Figure 8 , the flexibility of the display layer DL is enhanced by forming an array of openings 64 to create serpentine segments (display layer portions DL-2) that extend between an array of display layer islands (display layer portions DL-1). In Figure 8In the display layer DL, portion DL-2 is an elongated strip structure with a tortuous path, enhancing flexibility. Interconnects (e.g., metal traces) can extend between portions DL-2 using intervening portions DL-1. The type of mesh shape, other mesh patterns that can be used in the substrate 44, and / or other patterns of the openings 64 in the substrate 44 can provide the substrate 44 with the ability to conform to surfaces with composite curvatures and / or other surfaces with curved cross-sectional profiles without adversely affecting the density of visible pixels on the surface of the display 14.

[0052] Figure 9 This illustrates a configuration where opening 64 can extend entirely through a portion of the display panel 14P (e.g., opening 64 can form a through-hole opening) while the interconnect substrate 44 does not contain an opening. Opening 64 can be formed in a manner such as... Figure 8 An array of openings 64 may have a slot shape (slit shape) such as Figure 6 The opening 64 may form a grid (see example). Figure 7 (Opening 64) or to generate a grid pattern (see, for example) Figure 8 (Opening 64). If desired, opening 64 may have other shapes (e.g., circular, triangular, serrated, hexagonal, etc.).

[0053] Figure 10 The diagram shows a way in which the opening 64 can extend completely through the base 44 (e.g., such that the base 44 has an array of slots, a grid-like opening, a grid pattern with meandering segments of connecting islands, etc.). Figure 10 The display panel 14P in the example does not have an opening.

[0054] Figure 11 The diagram illustrates a manner in which openings, such as opening 64, can be formed in both the substrate 44 and the display panel 14P. When both the substrate 44 and the display panel 14P contain openings, the openings in the substrate 44 and the display panel 14P can be aligned with each other and / or may include non-overlapping openings.

[0055] exist Figure 12 In the example, opening 64 only partially penetrates the display panel DL (which may be the display panel, interconnect substrate, adhesive layer, touch sensor layer, and / or other display layers). In this arrangement, opening 64 forms a recess rather than a through-hole opening. Recesses are such as Figure 12 The recesses may be formed in the upper and / or lower surfaces of the display panel 14P and / or the upper and / or lower surfaces of the interconnecting substrate 44 (as an example). The recesses and / or other openings in the panel 14P may or may not be aligned with the recesses and / or other openings in the substrate 44.

[0056] In some configurations, the display layer, such as Figure 13The display layer DL may have a thickness T that is thin enough to accommodate bending (e.g., to conform to a stretchable surface or a surface with complex curvature). The value of T may be less than 1 mm, less than 100 μm, less than 10 μm, less than 1 μm, less than 0.5 μm, at least 0.01 μm, or other suitable thickness.

[0057] Regular and / or irregular tile patterns can be used for one or more display layers (DLs). In a tiled arrangement, through-hole grid openings (gap) exist between adjacent tiles, allowing the tiles to be oriented independently (e.g., to conform to display areas with complex curvatures). Tiles can be rectangular, square, triangular, hexagonal, circular, or have other shapes with straight and / or curved edges. Figure 14 The example shows a corner portion of a display 14 containing a display layer DL divided into patches. The central portion of the display layer has an array of square display layer patches (e.g., rows and columns of patches). In the corners, the patches are formed with crescent shapes and / or other shapes with curved edges. Figure 15 This demonstrates a method of adapting to a circular display shape using patches that form annular segments around a central circular patch. Other patch shapes can be used if desired. Furthermore, if needed, Figure 14 The opening 64 of 15 may include a groove and a through hole or alternative to a through hole. Figure 14 The display layer DL of 14 may be a display panel such as display panel 14P, may be an interconnect substrate such as interconnect substrate 44, and / or may be any other suitable display layer structure for display 14 and may have curved surface areas.

[0058] It is desirable to pre-rotate the contacts formed on the display layer by an amount that will counteract the expected rotational movement of the display layer as it is stretched into place in the display 14 (e.g., to form a display layer with a composite curvature surface). As an example, consider... Figure 16 The base 44. For example... Figure 16 As shown, the substrate 44 has contacts 52C. As an example, contacts 52C may be formed as an array having rows and columns. It is anticipated that the clockwise rotation of the portion of the substrate 44 on which contacts 52C are formed will initially deliver contacts 52C counterclockwise, such that contacts 52C are oriented relative to the horizontal plane at a non-zero angle A (e.g., an angle of 1-45° or other suitable angle), such that axis 66 (which is parallel to the row extension of contacts 52C) is relative to horizontal axis 68 (which is parallel to...). Figure 16 The orientation of the X-axis is shown.

[0059] Figure 17The way in which the openings 64 stretch open (e.g., into diamond-like shapes) as the substrate 44 stretches into place (e.g., to conform to a desired shape having compound curvature or other curvature) is shown. The openings 64 provide enhanced flexibility to the substrate 44 to accommodate the desired curved shape, but the openings also tend to rotate the contacts 52C as the openings 64 deform during stretching. By orienting the contacts 52C at a non-zero angle prior to stretching the substrate 44, proper horizontal alignment of the display panel 14P and the contacts 52C is ensured (e.g., where the row axes 66 of the array of contacts 52C are oriented parallel to the X-axis and where the edges of the display panel tile extend horizontally and vertically or in other desired directions). In the case of this type of arrangement, the contacts 52C on opposite sides of a given opening 64 can be pre-rotated in opposite directions. For example, a set of contacts 52C on the upper left of a vertical slot-shaped opening can be pre-rotated counterclockwise to counteract the expected clockwise rotation as the substrate 44 stretches the opening open, while a corresponding set of contacts 52C on the upper right of the vertical slot-shaped opening can be pre-rotated clockwise to counteract the expected counterclockwise rotation as the substrate 44 stretches the opening open.

[0060] If desired, different portions of a display layer (e.g., the display panel 14P and / or the substrate 44) can be provided with different elasticity. For example, a rectangular region or other region of a display layer that includes contacts for mating with contacts in another display layer can be configured to be stiffer than surrounding regions. As one example, Figure 18 The display layer DL can have portions that are stiffer and thus have a greater modulus of elasticity than surrounding portions of the layer DL, such as the portion 70. The locally stiffened region such as the portion 70 can be formed by embedding a stiffening member (e.g., a stiffening plate) in the display layer DL, by attaching a stiffening member to the display layer DL using an adhesive, or using other stiffening arrangements. In the example shown in FIG. 7, the portion 70 is formed by embedding a stiffening plate 72 in the display layer DL. The portion 70 can be formed by embedding the stiffening plate 72 in the display layer DL using a two-shot injection molding process, for example. Figure 18 The region 70 can overlap a region in which an array of contacts is formed (e.g., to help support the contacts, and to prevent the contact locations from moving relative to one another, which would impose undesirable stresses on the contacts).

[0061] The local stiffening can be achieved by embedding a stiffening member (e.g., a stiffening plate) in the display layer DL, by attaching a stiffening member to the display layer DL using an adhesive, or using other stiffening arrangements. In the example shown in FIG. 7, the portion 70 is formed by embedding a stiffening plate 72 in the display layer DL. The portion 70 can be formed by embedding the stiffening plate 72 in the display layer DL using a two-shot injection molding process, for example. Figure 19 In the example shown in FIG. 7, the region 70 includes a first material 72 that is stiffer than a second surrounding material 74. The material 74 can be, for example, a flexible elastomeric material such as a flexible silicone, and the material 72 can be a silicone or other material that has been treated to enhance stiffness. The material 72 can be formed by locally treating the layer 74 and / or by embedding the material 72 in the material 74 using a two-shot injection molding process, for example. If desired, the material 72 can extend completely through the layer of material 74 in the display layer DL (see, e.g., FIG. 8). When using a two-shot injection molding process, the material 72 can be formed in the material 74 by using a mold that includes a recessed portion that is filled with the material 72 during the first shot of the two-shot injection molding process. Figure 20 Figure 18 , Figure 19 and Figure 20 ​When the display 14 is formed with an arrangement of the type shown in FIG. 8, the interconnect substrate contacts can be limited to the area 70, and can cooperate with corresponding display panel contacts on the display panel tile that respectively overlap corresponding areas in the area 70.

[0062] In addition to or instead of introducing locally stiffened areas to the display layer to support contacts such as the contacts 52C, if desired, the display 14 can include one or more display layers DL that have different amounts of flexibility in different areas to accommodate different amounts of surface curvature. As one example, consider a display 14 of the type shown in FIG. 9. Figure 21 In this example, the display 14 includes a central area with a circular outer shape, such as the area 82 surrounded by the circular ring area 80. The display 14 can be flat, or can have a slight domed shape in the area 82. In the area 80, the display 14 can have a significant compound curvature. The portion of the display layer DL that overlaps the area 82 can have less flexibility than the portion of the display layer DL that overlaps the area 80. This allows the display layer DL to bend and conform to the compound surface curvature of the area 80. As one example, in the display layer DL, there can be a denser pattern of openings 64 in the area 80 than in the area 82, a substrate material with a lower modulus of elasticity can be used in the area 80 than in the area 82, a thinner material and / or larger openings 64 can be used in the area 80 than in the area 82, etc. This approach can be used regardless of the shape of the display 14. For example, in a configuration of the type shown in FIG. 10, where the display 14 has a rectangular outer shape with rounded corners characterized by a compound curvature, the display layer DL can be configured to be more flexible in the corner areas 80 than in the central and edge areas 82. Figure 22

[0063] In a configuration of the type shown in FIG. 11, where the display 14 has a rectangular outer shape with rounded corners characterized by a compound curvature, the display layer DL can be configured to be more flexible in the corner areas 80 than in the central and edge areas 82. Figure 23 ​In an illustrative configuration of the display 14 shown in cross-sectional side view, the display panel 14P has rigid display panel tiles that each include an array of multiple pixels (e.g., an N x N array of pixels P). The display panel tiles can be formed, for example, from a substrate material such as rigid printed circuit material (e.g., FR4) or other hard polymer. This approach helps prevent tile flexure that can create stress on the contact-to-contact joints. To cover the large area of the display 14 that includes regions with curved surfaces (e.g., regions of compound curvature), the display panel tiles can form a tiled array arrangement of the display panel 14P that extends across the surface of the display 14. Each display panel tile can have contacts that mate with corresponding contacts in the flexible substrate layer 44. A rigid polymer adhesive 84 (e.g., an underfill formed from a rigid polymer having a first modulus) can be used to help attach the display module 14P to the substrate 44. A flexible polymer adhesive 86 (e.g., a polymer adhesive having a second modulus that is less than the first modulus) can be formed on portions of the surface of the substrate 44 that are not covered by the rigid polymer adhesive 84. Because the polymer of the adhesive 86 is flexible, it allows the substrate 44 to flex and conform to the desired curved surface shape. The substrate 44 can optionally be locally stiffened under each set of contacts 48C. If desired, an encapsulant layer 88 (e.g., a layer of light-transmissive polymer encapsulant and / or inorganic encapsulant) can be formed over the surface of the display 14 to help protect the display 14 (e.g., to help protect the pixels in the display panel 14P).

[0064] The display 14 can be formed by laminating together the layers of interest, including the display panel 14P, the interconnect substrate 44, and / or additional layers such as additional polymer layers for adhesion and / or encapsulation, touch sensor layers and / or other layers including sensor circuitry, support structures (e.g., a thermoplastic substrate or other polymer support structure for the display 14 having a convex surface for supporting the underside of the substrate 44, a display cover layer, etc.). As shown, layers such as these layers (e.g., the layers 90) can be bonded together using a mold 92 under heat and / or pressure, the mold having flat and / or curved (convex and / or concave) opposing surfaces that are pressed together in a direction 94. Figure 24 Figure 24 The display 14 can be formed by laminating together the layers of interest, including the display panel 14P, the interconnect substrate 44, and / or additional layers such as additional polymer layers for adhesion and / or encapsulation, touch sensor layers and / or other layers including sensor circuitry, support structures (e.g., a thermoplastic substrate or other polymer support structure for the display 14 having a convex surface for supporting the underside of the substrate 44, a display cover layer, etc.). As shown, layers such as these layers (e.g., the layers 90) can be bonded together using a mold 92 under heat and / or pressure, the mold having flat and / or curved (convex and / or concave) opposing surfaces that are pressed together in a direction 94.

[0065] ​When attaching the layers 90 together, any suitable assembly sequence can be used. For example, the display panel 14P can be bonded to the substrate 44 (with or without an intervening polymer layer, such as a polymer layer used as an adhesive) before components (e.g., display driver integrated circuits, board-to-board connectors, etc.) are mounted to the underside of the substrate 44 or after these components have been mounted. All of the layers 90 can be attached together at one time using assembly tools (e.g., using a mold 92), or the layers 90 can be assembled in multiple steps if desired. As one example, the layers 90 forming the display 14, such as the display panel 14P and the substrate 44, can be laminated together in a first step, after which the assembled display panel and substrate 44 are attached to the inner surface of the cover layer 40 Figure 4 ) during a second step. Other assembly techniques can be used if desired.

[0066] According to one embodiment, an electronic device is provided that includes a housing and a display in the housing, the display configured to display an image, the display including a set of display panel tiles, each display panel tile in the set of display panel tiles having pixels and each display panel tile in the set of display panel tiles having display panel contacts, the set of display panel tiles configured to display the image, and a flexible interconnect substrate including a composite curvature region, the set of display panel tiles mounted to the flexible interconnect substrate and overlapping the composite curvature region, and the flexible interconnect substrate having interconnect substrate contacts that mate with the display panel contacts.

[0067] According to another embodiment, the flexible interconnect substrate includes an array of flexible reinforcement openings.

[0068] According to another embodiment, the flexible reinforcement openings include through-hole openings.

[0069] According to another embodiment, the through-hole openings are arranged in an array forming a grid pattern in the flexible interconnect substrate.

[0070] According to another embodiment, the flexible reinforcement openings include slot-shaped openings.

[0071] According to another embodiment, the display panel tiles have a polymer substrate formed of a first polymer having a first elastic modulus, and the flexible interconnect substrate is formed of a second polymer having a second elastic modulus that is less than the first elastic modulus.

[0072] According to another embodiment, the flexible interconnect substrate includes silicone.

[0073] According to another embodiment, the flexible interconnect substrate has a locally stiffened region.

[0074] According to another embodiment, the display panel contact pads are bonded to the interconnect substrate contact pads in the locally hardened regions.

[0075] According to another embodiment, the electronic device includes integrated circuits, each embedded in a respective one of the display panel tiles.

[0076] According to another embodiment, the electronic device includes integrated circuits, each embedded in a respective one of the display panel tiles.

[0077] According to another embodiment, the electronic device includes a board-to-board connector electrically coupled to the metal traces in the flexible substrate.

[0078] According to another embodiment, the electronic device includes an encapsulant layer covering the set of display panel tiles.

[0079] According to another embodiment, the display includes a transparent display cover layer overlapping the set of display panel tiles.

[0080] According to another embodiment, the interconnect substrate contact pads of the flexible interconnect substrate are oriented to compensate for rotation of the interconnect substrate contact pads and corresponding rotation of the display panel tiles when the flexible interconnect substrate is stretched to conform to the compound curvature region.

[0081] According to another embodiment, the electronic device includes wireless transceiver circuitry and a wristband coupled to the housing.

[0082] According to one embodiment, an electronic device is provided, comprising: a housing; and a display coupled to the housing, the display including at least one display panel having an array of pixels configured to display images, and including a separate flexible elastomeric interconnect substrate coupled to the display panel with an adhesive, the display panel having inward-facing contact pads that mate with corresponding outward-facing contact pads on the flexible elastomeric interconnect substrate, and the flexible elastomeric interconnect substrate including metal traces that form interconnects coupled to the outward-facing contact pads.

[0083] According to another embodiment, the flexible elastomeric interconnect substrate is stretched to form a surface having compound curvature overlapped by the display panel.

[0084] According to another embodiment, the electronic includes inward-facing interconnect substrate contact pads on an inward-facing surface of the flexible elastomeric interconnect substrate, and display driver integrated circuits coupled to the inward-facing interconnect substrate contact pads.

[0085] According to an embodiment, a display is provided, comprising: display panel tiles, each of the display panel tiles having pixels and embedded integrated circuits electrically coupled to the pixels of the display panel tile; and a flexible interconnect substrate containing metal traces forming interconnects, the flexible interconnect substrate having a compound curvature region overlapped by at least some of the display panel tiles, the display panel tiles each having display panel tile contacts that mate with corresponding flexible interconnect substrate contacts on the flexible interconnect substrate, and the interconnects, the flexible interconnect substrate contacts, the display panel tile contacts, and signal lines in the display panel tiles are configured to route signals to the embedded integrated circuits.

[0086] According to another embodiment, the display panel tiles comprise rigid printed circuit board material, and the flexible interconnect substrate comprises an elastomeric polymer layer having an array of flexible reinforcement openings.

[0087] The foregoing is merely illustrative and various modifications can be made to the described embodiments. The foregoing embodiments can be implemented independently or in any combination.

Claims

1. An electronic device, comprising: shell; and The display within the housing, configured to display images, wherein the display includes: A set of display panel tiles, each of the set of display panel tiles having pixels and each of the set of display panel tiles having display panel contacts, wherein the set of display panel tiles is configured to display the image; and A flexible interconnect substrate includes a composite curvature region, wherein a set of display panel patches are mounted to the flexible interconnect substrate and overlap the composite curvature region, wherein the flexible interconnect substrate has interconnect substrate contacts that mate with display panel contacts, wherein the flexible interconnect substrate includes an array of flexible reinforcing openings, wherein the flexible interconnect substrate includes a first region and a second region surrounding the first region, the first region having a first elastic modulus and each first region overlapping a corresponding display panel patch in the set of display panel patches, the second region having a second elastic modulus less than the first elastic modulus, and wherein the display panel contacts engage with the interconnect substrate contacts in the first region, the interconnect substrate contacts being oriented to compensate for rotation of the interconnect substrate contacts and corresponding rotation of the display panel patches when the flexible interconnect substrate is stretched to conform to the composite curvature region.

2. The electronic device according to claim 1, wherein the flexible reinforced opening includes a through-hole opening.

3. The electronic device of claim 2, wherein the via openings are arranged in an array to form a grid pattern in the flexible interconnect substrate.

4. The electronic device of claim 2, wherein the flexible reinforced opening comprises a slot-shaped opening.

5. The electronic device of claim 1, wherein the display panel patch has a polymer substrate formed of a polymer.

6. The electronic device of claim 1, wherein the flexible interconnect substrate comprises silicone resin.

7. The electronic device of claim 1 further comprises an integrated circuit, wherein each integrated circuit is embedded in a corresponding display panel patch in the display panel patch.

8. The electronic device of claim 1 further includes an integrated circuit electrically coupled to a metal trace in the flexible interconnect substrate.

9. The electronic device of claim 1, further comprising a board-to-board connector electrically coupled to a metal trace in the flexible interconnect substrate.

10. The electronic device of claim 1, further comprising an encapsulating layer covering the set of display panel patches.

11. The electronic device of claim 1, wherein the display further comprises a transparent display overlay layer overlapping the set of display panel patches.

12. The electronic device according to claim 1, further comprising: Wireless transceiver circuit; and A wristband, which is coupled to the housing.

13. An electronic device, comprising: shell; and A display coupled to the housing, wherein the display includes at least one display panel having a pixel array configured to display an image, and includes a separate flexible elastomeric interconnect substrate coupled to the display panel with an adhesive, wherein the display panel has inwardly facing contacts that contact corresponding outwardly facing contacts on the flexible elastomeric interconnect substrate using a conductive material, wherein the adhesive surrounds the conductive material and includes an elastomer configured to deform when portions of the flexible elastomeric interconnect substrate and the display panel move relative to each other, and wherein the flexible elastomeric interconnect substrate includes metal traces that form interconnects coupled to the outwardly facing contacts.

14. The electronic device of claim 13, wherein the flexible elastomer interconnect substrate is stretched to form a surface with a composite curvature overlapping the display panel.

15. The electronic device of claim 14, further comprising: Inward-facing interconnect base contacts on the inward-facing surface of the flexible elastomer interconnect base; and The display driver integrated circuit is coupled to the inward-facing interconnect substrate contacts.

16. A display comprising: Display panel patches, each of the display panel patches having a pixel and an embedded integrated circuit electrically coupled to the pixel of the display panel patch; and A flexible interconnect substrate includes an array of slot-shaped openings and metal traces forming interconnects. The flexible interconnect substrate has a composite curvature region overlapping at least some of the display panel patches. The flexible interconnect substrate is in a stretched state to conform to the composite curvature region. Each display panel patch has a display panel patch contact that engages with a corresponding flexible interconnect substrate contact on the flexible interconnect substrate. At least some of the flexible interconnect substrate contacts are configured to be in a rotationally offset position when the flexible interconnect substrate is in a non-stretched state, and wherein the at least some of the flexible interconnect substrate contacts are configured to move from the rotationally offset position to a rotationally aligned position in response to stretching the array of slot-shaped openings when the flexible interconnect substrate is in a stretched state.

17. The display of claim 16, wherein the display panel patch comprises a rigid printed circuit board material, and wherein the flexible interconnect substrate comprises an elastomeric polymer layer having an array of said slot-shaped openings.

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