PATENT DOCUMENT

Publication Number: US-9110320-B2
Application Number: US-201213585666-A
Country: US
Kind Code: B2

Title: Display with bent inactive edge regions

Abstract:
An electronic device may be provided with a display having substrate layers such as a glass color filter layer substrate and a glass thin-film-transistor layer substrate. Display layers such as first and second layers of polymer, a liquid crystal layer interposed between the layers of polymer, color filter elements, and thin-film-transistor circuitry may be formed between the color filter layer substrate and the thin-film-transistor layer substrate. Flexible inactive portions of the display layers may protrude outward from between the color filter layer substrate and the thin-film-transistor substrate. Touch sensor circuitry may be formed from a flexible polymer substrate. The touch sensor circuitry may include conductive touch sensor lines and capacitive electrodes. Each conductive line may be coupled to only a single end of a respective one of the capacitive electrodes.

Claims:
What is claimed is: 
     
       1. A display, comprising:
 first and second glass substrate layers; and 
 display layers interposed between the first and second glass substrate layers, wherein the display layers include a liquid crystal display layer, first and second polymer layers, color filter elements, and thin-film-transistor circuitry, wherein the color filter elements and thin-film-transistor circuitry are interposed between the first and second polymer layers, wherein the display layers have an active area containing display pixels and have an inactive area, wherein the active area is located between the first and second glass substrate layers, and wherein at least one of the polymer layers protrudes outwardly from between the first and second glass substrate layers and has a bend. 
 
     
     
       2. The display defined in  claim 1  wherein the color filter elements are formed on the first polymer layer. 
     
     
       3. The display defined in  claim 1  wherein the first and second polymer layers comprise polyimide. 
     
     
       4. The display defined in  claim 1  further comprising thin-film-transistor gate driver circuitry, wherein the thin-film-transistor gate driver circuitry is formed on a portion of the polymer layer that protrudes outwardly from between the first and second glass substrate layers. 
     
     
       5. The display defined in  claim 1  wherein the color filter elements are formed on the first polymer layer, the display further comprising:
 a black mask border on the first polymer layer; and 
 an array of display pixels each of which contains a thin-film-transistor on the second polymer layer. 
 
     
     
       6. The display defined in  claim 5  wherein the thin-film-transistors include indium gallium zinc oxide transistors. 
     
     
       7. The display defined in  claim 1  further comprising:
 an array of display pixels on the second polymer layer; and 
 conductive lines on the second polymer layer, wherein the conductive lines include gate lines and data lines. 
 
     
     
       8. The display defined in  claim 7  wherein the display layers are bent along at least one horizontal fold line, at least one vertical fold line, and at least one diagonal fold line and wherein the conductive lines include at least one conductive line segment that runs perpendicular to the diagonal fold line. 
     
     
       9. The display defined in  claim 1  further comprising at least one display driver integrated circuit, wherein the display driver integrated circuit is mounted to the second polymer layer within the inactive area. 
     
     
       10. The display defined in  claim 1  further comprising:
 at least one display driver integrated circuit; and 
 a flexible printed circuit substrate on which the display driver integrated circuit is mounted. 
 
     
     
       11. The display defined in  claim 10  wherein the flexible printed circuit is coupled to conductive lines on the second polymer layer. 
     
     
       12. The display defined in  claim 11  wherein the second polymer layer includes an array of display pixels and gate lines and data lines in the conductive lines that distribute signals from the display driver integrated circuit to the display pixels. 
     
     
       13. An electronic device, comprising:
 a housing having a rectangular front face with opposing upper and lower edges and opposing left and right edges; 
 a glass color filter layer substrate; 
 a glass thin-film-transistor layer substrate; and 
 display layers interposed between the glass color filter layer substrate and the glass thin-film-transistor layer substrate, wherein the display layers include color filter elements and thin-film-transistor circuitry interposed between first and second polymer layers, wherein the polymer layers include a flexible left inactive edge portion that extends outwards from between the glass color filter layer substrate and the glass thin-film-transistor layer substrate along the left edge of the housing and include a flexible right inactive edge portion that extends outwards from between the glass color filter layer substrate and the glass thin-film-transistor layer substrate along the right edge of the housing. 
 
     
     
       14. The electronic device defined in  claim 13  wherein the flexible left inactive edge portion has a right-angle bend and wherein the flexible right inactive edge portion has a right-angle bend.

Description:
BACKGROUND 
     This relates generally to electronic devices, and more particularly, to electronic devices with displays. 
     Electronic devices often include displays. For example, cellular telephones and portable computers often include displays for presenting information to a user. An electronic device may have a housing such as a housing formed from plastic or metal. Components for the electronic device such as display components may be mounted in the housing. 
     It can be challenging to incorporate a display into the housing of an electronic device. Size and weight are often important considerations in designing electronic devices. If care is not taken, displays may be bulky or may be surrounded by overly large borders. 
     It would therefore be desirable to be able to provide improved displays for electronic devices. 
     SUMMARY 
     An electronic device may be provided with a display having a substrate layers such as a glass color filter layer substrate and a glass thin-film-transistor layer substrate. Display layers such as layers of polymer, a liquid crystal layer interposed between the layers of polymer, color filter elements, and thin-film-transistor circuitry may be formed between the color filter layer substrate and the thin-film-transistor layer substrate. 
     The display layers may include an active region that contains an array of display pixels formed from thin-film-transistors. Conductive lines such as gate lines and data lines may couple display driver circuitry to the display pixels. The display driver circuitry may include one or more display driver integrated circuits. 
     Flexible inactive portions of the display layers may protrude laterally outward from between the color filter layer substrate and the thin-film-transistor substrate. The flexible inactive portions of the display layers may be bent to form bent edge portions of the display layers. The display driver circuitry may be mounted in the inactive portions of the display layers or on a flexible printed circuit that is coupled to the inactive portions of the display layers. Gate driver thin-film-transistor circuitry may be formed on one or more inactive bent edges of the display layer. 
     The flexible inactive portions of the display layers may be bent along horizontal fold lines, vertical fold lines, and diagonal fold lines. The conductive lines that are used in routing signals on the display layers may include diagonal conductive line segments that run perpendicular to diagonal bends in the flexible display layers. 
     Touch sensor circuitry may be formed on a flexible polymer substrate. The touch sensor circuitry may overlap the display pixels in the active area of the display. Conductive capacitive touch sensor electrodes such as elongated indium tin oxide electrodes that extend from edge to edge in the touch sensor may be formed on the flexible polymer substrate. Conductive lines may be coupled to the elongated electrodes. Each conductive line may be coupled to only a single end of a respective one of the capacitive touch senor electrodes. The flexible touch sensor substrate may be folded along only a single edge of the touch sensor or on two or more edges. 
     Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative electronic device such as a laptop computer with a display in accordance with an embodiment of the present invention. 
         FIG. 2  is a perspective view of an illustrative electronic device such as a handheld electronic device with a display in accordance with an embodiment of the present invention. 
         FIG. 3  is a perspective view of an illustrative electronic device such as a tablet computer with a display in accordance with an embodiment of the present invention. 
         FIG. 4  is a schematic diagram of an illustrative electronic device with a display in accordance with an embodiment of the present invention. 
         FIG. 5  is a cross-sectional side view of an illustrative display in accordance with an embodiment of the present invention. 
         FIG. 6  is a cross-sectional side view of a pair of display layer substrates such as a color filter layer substrate and a thin-film-transistor layer substrate for a display in accordance with an embodiment of the present invention. 
         FIG. 7  is a cross-sectional side view of the illustrative pair of display layer substrates of  FIG. 6  following formation of color filter elements and a layer of thin-film transistor circuitry in accordance with an embodiment of the present invention. 
         FIG. 8  is a cross-sectional side view of an illustrative display structure in which a color filter layer and thin-film-transistor layer have been attached to each other to form a liquid crystal display in accordance with an embodiment of the present invention. 
         FIG. 9  is a cross-sectional side view of a liquid crystal display having a rigid active area and flexible edges formed by removing some of the substrate materials of  FIG. 8  in accordance with an embodiment of the present invention. 
         FIG. 10  is a top view of an illustrative display with a rigid active area and flexible edges showing how display traces may traverse both the rigid active area and the flexible edges in accordance with an embodiment of the present invention. 
         FIG. 11  is top view of a display with a rigid active area and flexible edges having gate driver circuitry mounted on the flexible edges in accordance with an embodiment of the present invention. 
         FIG. 12  is a top view of an illustrative touch sensor array with bent edge structure of the type that may be incorporated into a display with bent edges in accordance with an embodiment of the present invention. 
         FIG. 13  is a perspective view of an illustrative touch sensor with a bent edge in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices may include displays. The displays may be used to display images to a user. Illustrative electronic devices that may be provided with displays are shown in  FIGS. 1 ,  2 , and  3 . 
       FIG. 1  shows how electronic device  10  may have the shape of a laptop computer having upper housing  12 A and lower housing  12 B with components such as keyboard  16  and touchpad  18 . Device  10  may have hinge structures  20  that allow upper housing  12 A to rotate in directions  22  about rotational axis  24  relative to lower housing  12 B. Display  14  may be mounted in upper housing  12 A. Upper housing  12 A, which may sometimes referred to as a display housing or lid, may be placed in a closed position by rotating upper housing  12 A towards lower housing  12 B about rotational axis  24 . 
       FIG. 2  shows how electronic device  10  may be a handheld device such as a cellular telephone, music player, gaming device, navigation unit, or other compact device. In this type of configuration for device  10 , housing  12  may have opposing front and rear surfaces. Display  14  may be mounted on a front face of housing  12 . Display  14  may, if desired, have a display cover layer or other exterior layer that includes openings for components such as button  26 . Openings may also be formed in a display cover layer or other display layer to accommodate a speaker port (see, e.g., speaker port  28  of  FIG. 2 ). 
       FIG. 3  shows how electronic device  10  may be a tablet computer. In electronic device  10  of  FIG. 3 , housing  12  may have opposing planar front and rear surfaces. Display  14  may be mounted on the front surface of housing  12 . As shown in  FIG. 3 , display  14  may have a cover layer or other external layer (e.g., a color filter layer or thin-film-transistor layer) with an opening to accommodate button  26  (as an example). 
     The illustrative configurations for device  10  that are shown in  FIGS. 1 ,  2 , and  3  are merely illustrative. In general, electronic device  10  may be 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 headphone or earpiece device, or other wearable or miniature device, a television, a computer display that does not contain 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. 
     Housing  12  of device  10 , which is sometimes referred to as a case, may be formed of materials such as plastic, glass, ceramics, carbon-fiber composites and other fiber-based composites, metal (e.g., machined aluminum, stainless steel, or other metals), other materials, or a combination of these materials. Device  10  may be formed using a unibody construction in which most or all of housing  12  is formed from a single structural element (e.g., a piece of machined metal or a piece of molded plastic) or may be formed from multiple housing structures (e.g., outer housing structures that have been mounted to internal frame elements or other internal housing structures). 
     Display  14  may be a touch sensitive display that includes a touch sensor or may be insensitive to touch. Touch sensors for display  14  may be formed from an array of capacitive touch sensor electrodes, a resistive touch array, touch sensor structures based on acoustic touch, optical touch, or force-based touch technologies, or other suitable touch sensor components. Display  14  may have a rectangular shape or other suitable shapes. For example, display  14  may have a shape with upper and lower edges and right and left edges that is mounted within the front face of a housing structure for device  10  that has a rectangular front face or other housing structures with corresponding upper and lower sidewall edges and corresponding left and right sidewall edges. 
     Displays for device  10  may, in general, include image pixels formed from light-emitting diodes (LEDs), organic LEDs (OLEDs), plasma cells, electrowetting pixels, electrophoretic pixels, liquid crystal display (LCD) components, or other suitable image pixel structures. In some situations, it may be desirable to use LCD components to form display  14 , so configurations for display  14  in which display  14  is a liquid crystal display are sometimes described herein as an example. It may also be desirable to provide displays such as display  14  with backlight structures, so configurations for display  14  that include a backlight unit may sometimes be described herein as an example. Other types of display technology may be used in device  10  if desired. The use of liquid crystal display structures and backlight structures in device  10  is merely illustrative. 
     A display cover layer may cover the surface of display  14  or a display layer such as a color filter layer, thin-film transistor layer or other portion of a display may be used as the outermost (or nearly outermost) layer in display  14 . For example, a color filter layer or thin-film transistor layer that is covered by a polarizer layer may form the outermost layer for device  10 . A display cover layer or other outer display layer may be formed from a transparent glass sheet, a clear plastic layer, or other transparent member. 
     Touch sensor components such as an array of capacitive touch sensor electrodes formed from transparent materials such as indium tin oxide may be formed on the underside of a display cover layer, may be formed on a separate display layer such as a glass or polymer touch sensor substrate, or may be integrated into other display layers (e.g., substrate layers such as a thin-film transistor layer). 
     A schematic diagram of an illustrative configuration that may be used for electronic device  10  is shown in  FIG. 4 . As shown in  FIG. 4 , electronic device  10  may include control circuitry  29 . Control circuitry  29  may include storage and processing circuitry for controlling the operation of device  10 . Control circuitry  29  may, for example, 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. Control circuitry  29  may include processing circuitry based on one or more microprocessors, microcontrollers, digital signal processors, baseband processors, power management units, audio codec chips, application specific integrated circuits, etc. 
     Control circuitry  29  may be used to run software on device  10 , such as operating system software and application software. Using this software, control circuitry  29  may present information to a user of electronic device  10  on display  14 . When presenting information to a user on display  14 , sensor signals and other information may be used by control circuitry  29  in making adjustments to the strength of backlight illumination that is used for display  14 . 
     Input-output circuitry  30  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 circuitry  30  may include communications circuitry  32 . Communications circuitry  32  may include wired communications circuitry for supporting communications using data ports in device  10 . Communications circuitry  32  may also include wireless communications circuits (e.g., circuitry for transmitting and receiving wireless radio-frequency signals using antennas). 
     Input-output circuitry  30  may also include input-output devices  34 . A user can control the operation of device  10  by supplying commands through input-output devices  34  and may receive status information and other output from device  10  using the output resources of input-output devices  34 . 
     Input-output devices  34  may include sensors and status indicators  36  such as an ambient light sensor, a proximity sensor, a temperature sensor, a pressure sensor, a magnetic sensor, an accelerometer, and light-emitting diodes and other components for gathering information about the environment in which device  10  is operating and providing information to a user of device  10  about the status of device  10 . 
     Audio components  38  may include speakers and tone generators for presenting sound to a user of device  10  and microphones for gathering user audio input. 
     Display  14  may be used to present images for a user such as text, video, and still images. Sensors  36  may include a touch sensor array that is formed as one of the layers in display  14 . 
     User input may be gathered using buttons and other input-output components  40  such as touch pad sensors, buttons, joysticks, click wheels, scrolling wheels, touch sensors such as sensors  36  in display  14 , key pads, keyboards, vibrators, cameras, and other input-output components. 
     A cross-sectional side view of an illustrative configuration that may be used for display  14  of device  10  (e.g., for display  14  of the devices of  FIG. 1 ,  FIG. 2 , or  FIG. 3  or other suitable electronic devices) is shown in  FIG. 5 . As shown in  FIG. 5 , display  14  may include backlight structures such as backlight unit  42  for producing backlight  44 . During operation, backlight  44  travels outwards (vertically upwards in the orientation of  FIG. 5 ) and passes through display pixel structures in display layers  46 . This illuminates any images that are being produced by the display pixels for viewing by a user. For example, backlight  44  may illuminate images on display layers  46  that are being viewed by viewer  48  in direction  50 . 
     Display layers  46  may be mounted in chassis structures such as a plastic chassis structure and/or a metal chassis structure to form a display module for mounting in housing  12  or display layers  46  may be mounted directly in housing  12  (e.g., by stacking display layers  46  into a recessed portion in housing  12 ). Display layers  46  may form a liquid crystal display or may be used in forming displays of other types. 
     In a configuration in which display layers  46  are used in forming a liquid crystal display, display layers  46  may include a liquid crystal layer such a liquid crystal layer  52 . Liquid crystal layer  52  may be sandwiched between display layers such as display layers  58  and  56 . Layers  56  and  58  may be interposed between lower polarizer layer  60  and upper polarizer layer  54 . 
     Layers  58  and  56  may be formed from transparent substrate layers such as clear layers of glass or plastic. Layers  56  and  58  may be layers such as a thin-film transistor layer and/or a color filter layer. Conductive traces, color filter elements, transistors, and other circuits and structures may be formed on the substrates of layers  58  and  56  (e.g., to form a thin-film transistor layer and/or a color filter layer). Touch sensor electrodes may also be incorporated into layers such as layers  58  and  56  and/or touch sensor electrodes may be formed on other substrates. 
     With one illustrative configuration, layer  58  may be a thin-film transistor layer that includes an array of thin-film transistors and associated electrodes (display pixel electrodes) for applying electric fields to liquid crystal layer  52  and thereby displaying images on display  14 . Layer  56  may be a color filter layer that includes an array of color filter elements for providing display  14  with the ability to display color images. If desired, the positions of color filter layer  56  and thin-film-transistor layer  58  may be inverted so that the thin-film-transistor layer is located above the color filter layer. 
     During operation of display  14  in device  10 , control circuitry  29  (e.g., one or more integrated circuits such as components  68  on printed circuit  66  of  FIG. 5 ) may be used to generate information to be displayed on display (e.g., display data). The information to be displayed may be conveyed from circuitry  68  to display driver integrated circuit  62  using a signal path such as a signal path formed from conductive metal traces in flexible printed circuit  64  (as an example). 
     Display driver integrated circuit  62  may be mounted on thin-film-transistor layer driver ledge  82  or elsewhere in device  10 . A flexible printed circuit cable such as flexible printed circuit  64  may be used in routing signals between printed circuit  66  and thin-film-transistor layer  60 . If desired, display driver integrated circuit  62  may be mounted on printed circuit  66  or flexible printed circuit  64 . Printed circuit  66  may be formed from a rigid printed circuit board (e.g., a layer of fiberglass-filled epoxy) or a flexible printed circuit (e.g., a flexible sheet of polyimide or other flexible polymer layer). 
     Backlight structures  42  may include a light guide plate such as light guide plate  78 . Light guide plate  78  may be formed from a transparent material such as clear glass or plastic. During operation of backlight structures  42 , a light source such as light source  72  may generate light  74 . Light source  72  may be, for example, an array of light-emitting diodes. 
     Light  74  from light source  72  may be coupled into edge surface  76  of light guide plate  78  and may be distributed laterally throughout light guide plate  78  due to the principal of total internal reflection. Light guide plate  78  may include light-scattering features such as pits or bumps. The light-scattering features may be located on an upper surface and/or on an opposing lower surface of light guide plate  78 . 
     Light  74  that scatters upwards from light guide plate  78  may serve as backlight  44  for display  14 . Light  74  that scatters downwards may be reflected back in the upwards direction by reflector  80 . Reflector  80  may be formed from a reflective material such as a layer of white plastic or other shiny materials. 
     To enhance backlight performance for backlight structures  42 , backlight structures  42  may include optical films  70 . Optical films  70  may include diffuser layers for helping to homogenize backlight  44  and thereby reduce hotspots, compensation films for enhancing off-axis viewing, and brightness enhancement films (also sometimes referred to as turning films) for collimating backlight  44 . Optical films  70  may overlap the other structures in backlight unit  42  such as light guide plate  78  and reflector  80 . For example, if light guide plate  78  has a rectangular footprint when viewed in direction  50  of  FIG. 5  (i.e., when viewed as a top view), optical films  70  and reflector  80  may have a matching rectangular footprint. 
     Display  14  may be characterized by a central rectangular active area (sometimes referred to as active area AA) and may be characterized by an inactive border region (sometimes referred to as inactive area IA) that surrounds the periphery of the active area. In the active region, thin-film transistor layer  58  may contain an array of display pixels. Each display pixel may include electrode structures. Each display pixel may also include a thin-film transistor for controlling the amount of electric field that is applied to liquid crystal layer  52  by the electrode structures. Display  14  may include signal lines such as gate lines and data lines. During operation, gate line signals on the gate lines and data lines signals on the data lines may be provided to the array of display pixels. The gate line and data line signals may be used to control the display pixels and thereby display images on display  14  for viewer  48 . 
     To accommodate display  14  within housing  12  of device  10  without creating excessively large inactive borders, it may be desirable to form one or more edges of display  14  (and, if desired, a touch sensor in display  14 ) using flexible layers of material. As an example, display  14  may be provided with one or more layers of flexible polymer sheets such as polyimide sheets or other polymer layers. These layers may be bent along the edges of display  14  so that some or all of the inactive surface area of display  14  is folded away from the exposed active area of the display. 
     For example, one or more strips of flexible inactive edge material in display  14  may be bent downwards at a right angle (or other suitable angle), thereby removing the flexible strips of material from the planar front face of the display. With the edges of the display folded out of the way, display  14  may have a borderless or nearly borderless appearance along one or more of its edges when viewed from the front by a user of device  10 . 
     The central active area of the display may be formed from flexible display layers or may be formed from rigid structures. The use of rigid display structures such as structures that include one or more layers of glass substrate, may help improve display performance (e.g., by ensuring that the vertical separation between a thin-film-transistor layer and a color filter layer is accurately maintained at a desired value). To allow the edges of the display to bend, display  14  may be formed from a rigid substrate with flexible edges that extend laterally outwards from the rigid central display region. A display of this type may be formed by attaching rigid substrate structures to the central active portion of a flexible display or by otherwise rigidly supporting the central portion of a display while allowing edge portions of the display to remain flexible. 
     With one suitable arrangement, which is illustrated in connection with  FIGS. 6 ,  7 ,  8 , and  9 , a rigid display with flexible edges may be formed by removing rigid edge portions of rigid display substrate layers so that underlying flexible edge portions of the display protrude outwards from central rigid display region. 
     As shown in  FIG. 6 , display layers  90  for forming display  14  may initially include a pair of rigid substrate layers such as substrate layers  560  and  580 . Polymer layers such as polymer layers  92  and  94  may be formed on the surfaces of substrate layers  560  and  580  using deposition techniques such as spraying, spinning, dripping, pad printing, screen printing, roller-based liquid resin dispensing, lamination, or other suitable polymer deposition techniques. The polymer materials that are used in forming polymer layers  92  and  94  may be materials that can be formed into thin flexible sheets such as polyimide or other flexible polymers. 
     Substrate layers  560  and  580  may be formed from sheets of glass or other rigid transparent substrate materials. The hardness of the material used in forming layers  560  and  580  (e.g., the hardness of the glass or other material used in forming layers  560  and  580 ) may be greater than the hardness used in forming polymer layers  92  and  94  (e.g., the hardness of the polyimide or other polymer used in forming layers  92  and  94 ). For a given thickness, layers  560  and  580  may also be more rigid than display layers such as polymer layers  92  and  94 . 
     Substrate layer  560  may be used in forming a color filter layer and may therefore sometimes be referred to as a color filter layer substrate. Substrate  580  may be used in forming a thin-film-transistor layer and may therefore sometimes be referred to as a thin-film-transistor layer substrate. Layers  560  and  580  and layers  92  and  94  may have thicknesses in the range of 0.05 to 3 mm (as examples). 
     Following formation of polymer layers  92  and  94  on the inner surfaces of substrate layers  560  and  580 , layer  560  may be processed to form a color filter layer and layer  580  may be processed to form a thin-film transistor layer. As shown in  FIG. 7 , for example, color filter elements  100  and opaque masking material structures  98  may be formed on the inner surface of polymer layer  92 . Color filter elements  100  may be formed from colored polymer elements (e.g., red, blue, and green dyed polymeric elements arranged in a rectangular array). Color filter elements may be used in providing the active area (AA) of display  14  with the ability to display color images. 
     Opaque masking structures  98  may be formed from an opaque material such as black ink (e.g., a polymer that includes a material such as carbon black or a dye that is opaque to visible light) and may therefore sometimes be referred to as black masking material or black mask. Black mask  98  may be formed in strip that surrounds the rectangular periphery of the active area of display  14 . The use of black mask  98  may help hide internal structures in device  10  from view from the exterior of device  10 . Black mask material (sometimes referred to as black matrix material) may also be interspersed among color filter elements  100  (e.g., in the form of a grid). 
     Structures for thin-film transistor circuitry  102  may be formed on polymer layer  94  on the upper surface of thin-film-transistor layer substrate. Thin-film transistor circuitry  102  may include display pixel electrodes, thin-film transistors, gate lines, data lines, and other circuitry for forming an array of display pixels such as display pixels  104 . Display pixels  104  may be aligned with corresponding color filter elements  100  on color filter layer  56 . Gate driver circuitry may also be formed in thin-film transistor circuitry  102 . 
     If desired, configurations for display  14  in which thin-film-transistor layer  58  is formed above color filter layer  56  and/or in which color filter elements and thin-film-transistor display pixel structures are formed on a common substrate may be used. Arrangements in which color filter layer  56  is formed above thin-film-transistor layer  58  and in which color filter elements  100  and thin-film-transistor display pixels  104  are formed on separate substrates are sometimes described herein as an example. 
     Following formation of color filter layer  56  by depositing and patterning color filter elements  100  and black masking border  98  on polymer layer  92  on substrate layer  560  and following formation of thin-film-transistor layer  58  by depositing and patterning thin-film-transistor circuitry  102  (e.g., thin-film-transistor display pixels  104  and other display structures) on polymer layer  94  on substrate  580 , display structures  90  of  FIG. 8  may be formed. In particular, sealant  110  may be used to surround and enclose liquid crystal material  52  between color filter layer  56  and thin-film-transistor layer  58 . Sealant  110  may be formed from a bead of polymer resin that runs around the rectangular periphery of the display layers of  FIG. 8 . Sealant  110  may laterally confine liquid crystal  52  and may help define and maintain a desired vertical spacing between the opposing inner surfaces of color filter layer  56  and thin-film-transistor layer  58 . 
     As shown in  FIG. 8 , sealant  110  and some or all of black mask border region  98  may be formed in inactive edge portions of display structures  90  outside of active area AA. Because structures  90  of  FIG. 8  includes rigid substrates  560  and  580 , flexible display structures such as polymer layers  92  and  94 , color filter elements  100 , black mask  98 , and thin-film-transistor circuitry  102  (collectively flexible display layers  112 ) will be supported by rigid material and will not bend significantly in the configuration of  FIG. 8 . 
     To allow flexible display layers  112  to bend (e.g., to reduce the portion of the inactive border of display  14  that extends laterally outwards from rigid active area AA), edge portions of the rigid substrate layers may be removed (e.g., using wet etching, dry etching, scribing and breaking, or other suitable material removal schemes). For example, edge portions  560 E may be removed from color filter layer substrate  560  and edge portions  580 E may be removed from substrate  580 . 
     As shown in  FIG. 9 , the rigid glass portions of substrates  560  and  580  that are removed from flexible display layers  112  may be discarded to form a display having protruding flexible edge portions  112 E. Upper polarizer  54  may be formed on the upper surface of substrate  560  and lower polarizer  60  may be formed on the lower surface of substrate  580 . Flexible edge portions  112 E may be formed along one or more of the four peripheral edges of rectangular display  14 , may be formed along two or more peripheral edges (e.g., left and right edges or upper and lower edges), or may be formed on three or more or four or more edges of display  14 . To minimize the size of border width BW of the inactive portions of display  14  and device  10  outside of active area AA, flexible portions  112 E of flexible display layers  112  may be bent downwards out of the plane of the display that contains rigid substrates  560  and  580 . As shown in  FIG. 9 , for example, flexible edge portions  112 E of flexible display layers  112  may be bent downwards at a right angle with respect to the plane of substrates  560  and  580 . A minimum bend radius of 0.1 mm, greater than 0.1 mm, 0.1 mm to 1 mm, or less than 1 mm may be used to ensure that flexible display layers  112  are not damaged by the bend. 
     Driver circuitry  62  may be mounted on a bent edge portion of display  14  such as the right-hand bent edge portion  112 E of  FIG. 9  or may be mounted on a separate substrate such as a substrate associated with a flexible circuit cable (as examples). 
     Even when display portions such as display edge portions  112 E of display  12  are bent at an angle of 30° or more, 70° or more, or 90° or more with respect to the plane of display  14 , signals may be routed from external control circuitry such as display driver integrated circuit  62  ( FIG. 5 ) to display pixels  104  using conductive lines such as gate lines and data lines that traverse the bent portion of flexible edges  112 E. 
       FIG. 10  is a top view of display  14  showing an illustrative configuration that may be used for display  14  when flexible edges  112 E are to be bent. As shown in  FIG. 10 , display pixels  104  may be arranged in a rectangular array of rows and columns in active area AA of display  14 . 
     Each display pixel  104  may include electrode structures and thin-film transistor structures such as thin-film transistors  122 . Thin-film transistors in display  14  such as transistors  122  may be formed from polycrystalline or amorphous semiconductors such as polysilicon, amorphous silicon, indium gallium zinc oxide other oxide semiconductors, or other semiconductor materials. 
     Display pixels  104  may be supplied with data signals over data lines  118 . The gates of the transistors in display pixels  104  may be controlled by gate line control signals that are provided to display pixels  104  over gate lines  116 . 
     Conductive lines  114  may be used to route signals to conductive lines such as data lines  118  and gate lines  116  from control circuitry such as display driver integrated circuit  62  or other display driver circuitry. Lines  114  may be formed from metal traces (e.g., aluminum lines, copper lines, traces formed from two or more metals, etc.), traces of indium tin oxide, or other conductive materials. 
     Display driver integrated circuit  62  may be mounted on edge region  112 E of flexible display layers  112  or may be mounted on a separate substrate such as substrate  64 . Substrate  64  may be a rigid printed circuit board or a flexible printed circuit such as a flexible printed circuit formed from a sheet of polyimide or other flexible layer of dielectric material. Substrate  64  may contain conductive lines that mate with conductive lines  114  at connection  124 . Connection  124  may be formed using anisotropic conductive film that is interposed between lines  114  and the mating lines on substrate  64  or may be formed from other conductive structures (welds, board-to-board connectors, etc.). 
     Flexible edge portions  112 E of flexible display layers  112  may be bent along the dashed lines of  FIG. 10  such as horizontal fold lines FH, vertical fold lines FV, and diagonal fold lines FD. To help prevent lines  114  from becoming damaged during the bending process, it may be desirable to orient lines  114  so that each line  114  crosses the fold lines perpendicular to the fold lines, as shown in  FIG. 10 . Lines  114  may, for example, include diagonal portions such as diagonal segments  114 D that run perpendicular to diagonal fold lines FD. Horizontal line segments may be used to cross vertical fold lines FV and vertical line segments may be used to cross horizontal fold lines FH. 
       FIG. 11  is a top view of display  14  in a configuration in which multiple integrated circuits  62  are being used to implement display driver circuitry for display  14 . Display  14  of  FIG. 11  includes thin-film transistor circuitry on flexible display layer edges  112 E such as gate driver circuitry  126 . Gate driver circuitry  126  may include a column of gate driver circuits. Each gate driver circuit may be used in asserting a gate line control signal for a respective row of display pixels  104 . Each gate driver circuit may, for example, include a respective gate driver having an output coupled to a respective one of gate lines  116 . Gate driver circuitry  126  may be formed along one or more edges of display  14 . For example, gate driver circuitry  126  may be formed along left flexible edge strip  112 E of flexible display layers  112  or may, if desired, be formed on opposing display edges such as opposing right and left (or upper and lower) display edges. 
     Signals for controlling display  14  may be routed to display driver integrated circuits  62  using a bus structure such as cable  64 . Cable  64  may be a flexible printed circuit with metal traces coupled to conductive lines  114  on flexible display layers  112 . If desired, one or more display driver integrated circuits may be formed on cable  64 . 
     If desired, display  14  may be provided with touch sensor capabilities. As an example, a substrate layer such as layer  560 , layer  580 , one of the other layers in flexible display layers  112 , or an additional layer or layers of display  14  may form a transparent dielectric substrate on which an array of capacitive touch sensor electrodes is formed. 
       FIG. 12  is a top view of an illustrative touch sensor of the type that may be incorporated into layer  560 , layer  580 , one of the other layers in flexible display layers  112 , or an additional layer or layers in display  14 . As shown in  FIG. 12 , touch sensor  128  may be formed from an array of patterned transparent capacitor electrodes such as electrodes  142  and  144 . Electrodes  142  and  144  may form an active portion of touch sensor  128  and may be configured to overlap active area AA of display  14  (e.g., by incorporating the structures of  FIG. 12  in layers  112  of display  14  and/or by overlapping touch sensor  128  with the thin-film-transistor layer and color filter layer. 
     Electrodes  142  and  144  may be formed from a transparent conductive material such as indium tin oxide and may be formed on one or both sides of a flexible clear polymer substrate such as flexible substrate  130 . Each electrode (in a configuration of the type shown in  FIG. 12 ) may have an elongated rectangular shape that runs across substrate  130 . In the  FIG. 12  example, electrodes  142  run vertically between the upper and lower edges of substrate  130  and electrodes  144  run horizontally between the right and left edges of substrate  130 . Other types of electrode patterns may be used if desired (e.g., linked pads having square or diamond shapes). A layer of dielectric (e.g., layer  130  or other dielectric material) may be interposed between electrodes  142  and electrodes  144 . 
     During operation, electrodes  142  may serve as drive electrodes and electrodes  144  may serve as sense electrodes. A signal such as an alternating current drive signal may be imposed on each drive electrode  142  using one of conductive lines  152 . Conductive lines  152  may each have one end that is connected to a terminal in driver line connector  154  and may have an opposing end that is connected to one of terminals  148  on the end of a respective one of drive electrodes  144 . With this arrangement, each driver line  152  may be connected to only one single end of a respective capacitive electrode. Sense lines  150  may likewise each have one end that is connected to a terminal in sense line connection  156  and may each have an opposing end that is connected to only a single end of a respective sense electrode. 
     The use of single-ended connections for forming the connection between each conductive line in touch sensor  128  and its associated capacitive electrode may help reduce the number of conductive lines  152  and  150  on touch sensor  128 . For example, a single-ended connection arrangement may make it possible to run conductive lines along only one side of the display rather than along opposing sides of the display to contact opposing ends of the electrodes. As a result, there need only be a single fold in touch sensor substrate  130  along the inactive side of the touch sensor that contains the conductive lines. The portion of the sensor that includes the drive line and sense line connectors (e.g. to attach external flexible printed circuit cables or other signal paths) may be formed in an inactive portion of display  14  that is not bent. This portion of the display may be located, for example, at the upper or lower end of an elongated display in configuration in which it is desired to minimize the inactive borders on the left and right edges of the display that extend between the upper and lower ends. 
     By minimizing the number of bends in the touch sensor, touch sensor reliability may be enhanced. If desired, double-ended connections may be made (e.g., connections in which each end of each capacitive electrode is coupled to a respective conductive line). Lines  152  and  150  may be formed on the same side of substrate  130  (using vias to connect one of these sets of lines to rear-surface capacitive electrodes) or lines  152  and  150  may be formed on opposing surfaces of substrate  130  (using vias to route one of these sets of lines from the front to the rear surface of substrate  130 ). 
     Connections  154  and  156  may be formed by attaching mating signal lines to lines  152  and  150  using anisotropic conductive film, using welds, using solder connections, or using connectors such as board-to-board connectors. 
     To minimize the inactive border region of display  14 , it may be desirable to bend flexible substrate  130  of touch sensor  128  along one or more edges of substrate  130 , along two or more edges of substrate  130 , or one three or more or four or more edges of substrate  130 . As an example, substrate  130  may be bent along fold line  138  so that edge portion  132  of substrate  130  is folded down and out of the plane of touch sensor electrodes  142  and  144  (e.g., out of the plane of planar central portion  134  of touch sensor  128  and/or optional fold line  140  (e.g., in a double-ended connection scheme) so that edge portion  136  is folded down and out of the plane of touch sensor electrodes  142  and  144  (e.g., out of the plane of touch sensor  128 ). 
     In the illustrative configuration for touch sensor  128  that is shown in the perspective view of touch sensor  128  of  FIG. 13 , single edge portion  132  of substrate  130  and touch sensor  128  has been bent downward at a right angle with respect to planar portion  134  along bend axis  138 . The process of folding edge portion  132  downwards and out of the plane of the touch sensor array may help reduce the lateral size of touch sensor  128 , thereby helping to minimize the inactive border region of display  14 . Planar portion  134  of touch sensor  128  contains capacitive touch sensor electrodes  142  and  144  and therefore preferably overlaps active area AA of display  14 . Inactive touch sensor edges such as edge  132  need not contain capacitive touch sensor electrodes  142  and  144  and may therefore not be placed on top of active area AA of display  14 . If desired, display  14  may contain touch sensor electrodes that run along one or more of the sides of device  10  (e.g., to form virtual buttons on one or more sidewalls of device  10 ). The illustrative configurations of touch sensor  128  that are shown in  FIGS. 12 and 13  are merely illustrative. 
     The foregoing is merely illustrative of the principles of this invention and various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention.

Metadata:
Filing Date: 20120814
Publication Date: 20150818
Grant Date: 20150818
Priority Date: 20120814
Inventors: CHEN CHENG
CHANG SHIH-CHANG
ZHONG JOHN Z.
CHEN WEI
ZHANG HAO
KANG SUNGGU
Assignee: APPLE INC
CPC Classifications: [{"code": "G02F2001/133388", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133514", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F2001/133302", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0412", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/13452", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/1333", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/044", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04102", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133305", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/1368", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133388", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133388", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133302", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133302", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0445", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02F1/1333", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133514", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/13452", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133305", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/13452", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F3/0445", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F3/0412", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/1368", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F3/0412", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2203/04102", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F2203/04102", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133305", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 48793543