PATENT DOCUMENT

Publication Number: US-9804639-B2
Application Number: US-201313968254-A
Country: US
Kind Code: B2

Title: Hinged portable electronic device with display circuitry located in base

Abstract:
An electronic device may have a housing with a lid that rotates relative to a base. A display in the lid may have a thin-film transistor layer. Display driver circuitry may be mounted to the thin-film transistor layer. A display timing controller integrated circuit may be mounted in the base. A rigid flex printed circuit may have a rigid portion in the base to which the display timing controller integrated circuit is mounted and may have a rigid portion in the lid. A flexible printed circuit portion of the rigid flex printed circuit may be used to couple the rigid printed circuit portion in the lid to the thin-film transistor layer. A flexible printed circuit portion of the rigid flex printed circuit that extends between the lid and the base may be formed from a double-shield-layer single-signal-line-layer flexible printed circuit.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a housing having a base and having a lid that rotates relative to the base; and 
 a rigid flex printed circuit having a first rigid printed circuit board portion in the lid, a second rigid printed circuit board portion in the base, a flexible printed circuit portion that extends between the first rigid printed circuit board portion and the second rigid printed circuit board portion, and a metal signal line layer that forms part of the first rigid printed circuit board portion, the second rigid printed circuit board portion, and the flexible printed circuit portion. 
 
     
     
       2. The electronic device defined in  claim 1  further comprising a display in the lid. 
     
     
       3. The electronic device defined in  claim 2  wherein the display comprises:
 liquid crystal display layers; and 
 a backlight unit, wherein the rigid flex printed circuit has a flexible printed circuit portion that extends between the first rigid printed circuit board portion and the liquid crystal display layers. 
 
     
     
       4. The electronic device defined in  claim 3  wherein the liquid crystal display layers include a thin-film transistor layer, wherein the display further comprises at least one column driver integrated circuit mounted on the thin-film transistor layer, and wherein the flexible printed circuit board portion that extends between the first rigid printed circuit board portion and the liquid crystal display layers is attached to the thin-film transistor layer. 
     
     
       5. The electronic device defined in  claim 4  further comprising a display timing controller integrated circuit mounted on the second rigid printed circuit board portion in the base. 
     
     
       6. The electronic device defined in  claim 5  wherein the flexible printed circuit portion that extends between the first rigid printed circuit board portion and the second rigid printed circuit portion comprises a single-signal-line-layer flexible printed circuit. 
     
     
       7. The electronic device defined in  claim 6  wherein the flexible printed circuit portion that extends between the first rigid printed circuit board portion and the second rigid printed circuit board portion has opposing outer layers of shielding metal that provide electromagnetic shielding. 
     
     
       8. The electronic device defined in  claim 7  wherein the flexible printed circuit portion that extends between the first rigid printed circuit board portion and the second rigid printed circuit board portion has a single layer of metal signal lines and has a neutral stress plane aligned with the single layer of metal signal lines. 
     
     
       9. A portable computer, comprising:
 a housing having a first housing portion and having a second housing portion that rotates relative to the first housing portion about a hinge axis; 
 a display in the first housing portion; 
 a printed circuit that is coupled to the display in the first housing portion, wherein the printed circuit comprises a first rigid printed circuit board portion in the first housing portion, a second rigid printed circuit board portion in the second housing portion, a flexible printed circuit portion that traverses the hinge axis and extends between the first rigid printed circuit board portion and the second rigid printed circuit board portion, and a metal signal line layer that forms part of the first rigid printed circuit board portion, the second rigid printed circuit board portion, and the flexible printed circuit portion; and 
 a display timing controller integrated circuit mounted on the second rigid printed circuit board portion in the second housing portion. 
 
     
     
       10. The portable computer defined in  claim 9  wherein the flexible printed circuit portion comprises a single-signal-line-layer flexible printed circuit. 
     
     
       11. The portable computer defined in  claim 9  wherein the flexible printed circuit portion comprises a double-shield-layer single-signal-line-layer flexible printed circuit. 
     
     
       12. The portable computer defined in  claim 9  wherein the display comprises display layers and a display driver integrated circuit mounted to one of the display layers. 
     
     
       13. A portable computer, comprising:
 a housing having a lid that rotates relative to a base; 
 a display in the lid; 
 display driver circuitry coupled to the display in the lid; 
 display control circuitry in the base; and 
 a printed circuit to which the display control circuitry is mounted, wherein the printed circuit is coupled between the display control circuitry in the base and the display driver circuitry, and wherein the printed circuit comprises a first rigid printed circuit board portion in the base, a first flexible printed circuit portion that extends between the first rigid printed circuit board portion and the display driver circuitry, and a metal signal line layer that forms part of both the first rigid printed circuit board portion and the first flexible printed circuit portion. 
 
     
     
       14. The portable computer defined in  claim 13  wherein the display comprises a substrate layer and wherein the display driver circuitry comprises a column driver integrated circuit mounted to the substrate layer. 
     
     
       15. The portable computer defined in  claim 14  wherein the printed circuit comprises a rigid flex printed circuit. 
     
     
       16. The portable computer defined in  claim 15  wherein the display control circuitry comprises a display timing controller integrated circuit mounted on the printed circuit. 
     
     
       17. The portable computer defined in  claim 16  wherein the printed circuit further comprises:
 a second rigid printed circuit board portion in the lid, wherein the display timing controller integrated circuit is mounted to the first rigid printed circuit board portion in the base. 
 
     
     
       18. The portable computer defined in  claim 17  wherein the printed circuit further comprises:
 a second flexible printed circuit portion that extends between the first rigid printed circuit board portion and the substrate layer, wherein the first flexible printed circuit portion extends between the first and second rigid printed circuit board portions. 
 
     
     
       19. The portable computer defined in  claim 18  wherein the first flexible printed circuit portion has opposing outer metal shielding layers.

Description:
BACKGROUND 
     This relates generally to electronic devices, and more particularly, to electronic devices with displays. 
     Electronic devices such as portable computers have displays for displaying images for a user. In a typical configuration, a portable computer housing includes a lid and a base that are attached to each other by a hinge. A keyboard is mounted in the base. The display of the portable computer is mounted in the lid. 
     There can be challenges involved in conveying signals between circuitry in the base of a portable computer and the display in the lid. Some computers use a bulky wiring harness that includes a coaxial cable. Other computers use a flexible printed circuit cable that is wrapped in a spiral shape. Configurations such as these may allow rotation of the lid relative to the base, but can require bulky hinge structures to provide sufficient space to accommodate the wiring harness or spiral flexible printed circuit. If care is not taken, undesired stresses may sometimes be imposed on cables that extend between the base and lid through a hinge that is subject to periodic movement. 
     It would therefore be desirable to provide improved ways in which to couple circuitry in the base of an electronic device to a device such as a display in the lid of the electronic device. 
     SUMMARY 
     An electronic device may have a housing with a lid that rotates relative to a base about a hinge axis. A display such as a liquid crystal display with a backlight unit may be provided in the lid. The liquid crystal display may have a layer of liquid crystal material interposed between a color filter layer and a thin-film transistor layer. 
     Some display circuitry such as column driver integrated circuits and other display driver circuitry may be mounted to the thin-film transistor layer. Other display circuitry such as a display timing controller integrated circuit may be mounted in the base. Printed circuit structures may be used in coupling circuitry in the base such as a timing controller or other display circuitry to circuitry in the lid such as display driver circuitry. 
     The printed circuit structures that are used in coupling circuitry in the base to circuitry in the lid may include a rigid flex printed circuit. The rigid flex printed circuit may have a rigid printed circuit board portion in the base to which the display timing controller integrated circuit is mounted and may have a rigid printed circuit board portion in the lid that helps to distribute signals within the lid. A flexible printed circuit portion of the rigid flex printed circuit may be used to couple the rigid printed circuit board portion in the lid to the thin-film transistor layer. Another flexible printed circuit portion of the rigid flex printed circuit may traverse the hinge axis and may extend between the rigid printed circuit board in the lid and the rigid printed circuit board in the base. 
     Flexible printed circuit board portions of the rigid flex may have a neutral stress plane that is aligned with a single layer of metal signal lines. Opposing outer metal shielding layers may be provided on the upper and lower surfaces of the flexible printed circuit portion that traverses the hinge axis to help prevent interference between display signals and antenna signals. 
     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 of the type that may be provided with a conductive path to couple circuitry in a housing base to circuitry in a housing lid in accordance with an embodiment. 
         FIG. 2  is a schematic diagram of an illustrative electronic device in accordance with an embodiment. 
         FIG. 3  is a cross-sectional side view of illustrative display components associated with a display in an electronic device such as a portable computer in accordance with an embodiment. 
         FIG. 4  is a top view of illustrative rigid flex printed circuit structures of the type that may be used to couple circuitry in a portable computer base to circuitry in a portable computer lid in accordance with an embodiment. 
         FIG. 5  is a cross-sectional side view of a portion of an illustrative rigid flex printed circuit cable structure of the type that may be used to minimize stress effects when the flexible portion of the cable structure is bent during opening and closing of a portable computer in accordance with an embodiment. 
         FIG. 6  is a cross-sectional end view of a hinge portion of a portable computer in a closed position showing how a rigid flex printed circuit can be used to route signals between a timing controller integrated circuit in a base of the portable computer to display driver circuits such as column drivers mounted on a thin-film transistor layer in a display in a lid of the portable computer in accordance with an embodiment. 
         FIG. 7  is a cross-sectional end view of the hinge portion of the portable computer of  FIG. 6  in an open position showing how a flexible length of the rigid flex printed circuit can bend to accommodate opening of the lid of the portable computer in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     An electronic device of the type that may be provided with a display is shown in  FIG. 1 . As shown in  FIG. 1 , electronic device  10  may have portions that move relative to each other such as upper housing  12 A and lower housing  12 B. Lower housing  12 B may sometimes be referred to as a main housing, base housing, or base. Upper housing  12 A may sometimes be referred to as a lid or display housing. 
     Electronic device  10  of  FIG. 1  may be a portable computer or other electronic device that has a folding lid or may be other electronic equipment. 
     Components such as keyboard  16  and touchpad  18  may be mounted on lower housing (base)  12 B. Base  12 B may also be used to house components such as a disk drive, audio components such as speakers, digital and analog signal ports, removable media slots, and other components. Device  10  may have hinge structures in region  20  that allow upper housing (lid)  12 A to rotate in directions  22  about rotational axis  24  relative to base  12 B. Display  14  may be mounted in lid  12 A. Lid  12 A may be placed in a closed position by rotating upper housing  12 A towards lower housing  12 B about rotational axis  24 . 
     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  for device  10  includes display pixels formed from liquid crystal display (LCD) components, organic light-emitting diode display components, electrophoretic display components, plasma display components, or other suitable display pixel structures. For example, display  14  may be a color liquid crystal display. 
     A display cover layer may cover the surface of display  14  or a display layer such as a color filter layer or other portion of a display may be used as the outermost (or nearly outermost) layer in display  14 . The outermost display layer may be formed from a transparent glass sheet, a clear plastic layer, or other transparent member. 
     A schematic diagram of an illustrative configuration that may be used for electronic device  10  is shown in  FIG. 2 . As shown in  FIG. 2 , electronic device  10  may include storage and processing circuitry  28  such as control circuitry  28 . Control circuitry  28  may include storage  32  such as hard disk drive storage, nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory configured to form a solid state drive), volatile memory (e.g., static or dynamic random-access-memory), etc. Processing circuitry  30  in control circuitry  28  may be used to control the operation of device  10 . The processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, baseband processors, power management units, audio codec chips, application specific integrated circuits, etc. 
     Control circuitry  28  may be used to run software on device  10 , such as internet browsing applications, voice-over-internet-protocol (VOIP) telephone call applications, email applications, media playback applications (e.g., applications that display moving and still images on display  14 ), operating system functions, etc. To support interactions with external equipment, control circuitry  28  may be used in implementing communications protocols. Communications protocols that may be implemented using control circuitry  28  include internet protocols, wireless local area network protocols (e.g., IEEE 802.11 protocols—sometimes referred to as WiFi®), protocols for other short-range wireless communications links such as the Bluetooth® protocol, cellular telephone protocols, etc. 
     Display  14  may include an array of display pixels such as display pixels  40 . Display pixels  40  may be, for example, liquid crystal display pixels formed on one or more display layers  46 . Display layers  46  may include polarizers, a color filter layer, a thin-film transistor layer, and a layer of liquid crystal material interposed between the color filter layer and the thin-film transistor layer. 
     Display circuitry such as timing controller integrated circuit  34 , gate driver circuitry  38 , and column driver integrated circuits  62  may be used in controlling the array of display pixels  40  in display  14  to present images on display  14  for a user of device  10 . Column driver circuitry  62  may provide data signals to data lines  45 . Gate driver circuitry  38  may be used to assert a scan signal on gate lines  43  (e.g., gate driver circuitry  38  may take each gate line high in sequence to load data on lines  45  into the pixels of the row associated with that gate line). Gate driver circuitry  38  and/or column driver circuitry  62  may be formed from thin-film circuits on a thin-film transistor layer or other substrate in display layers  46  and/or may be formed from integrated circuits mounted the thin-film transistor layer or other substrate in display layers  46  (e.g., on a glass substrate in a thin-film transistor layer that contains thin-film transistors associated with display pixels  40 ). Integrated circuits such as column driver integrated circuits may be attached to the thin-film transistor layer in display layers  46  using anisotropic conductive film (ACF) or solder joints (i.e., using a chip-on-glass arrangement). 
     Signal lines in communications path  64  may be used to couple display circuitry such as display timing controller integrated circuit  34  to display driver circuitry in display  14  such as column drivers  62  and/or gate drivers  38 . Path  64  may be formed from metal traces on one or more layers of a flexible printed circuit cable or other signal paths. Timing controller integrated circuit  34  may be coupled to control circuitry  28  via signal lines in communications path  84  (e.g., printed circuit traces, etc.). 
     Circuitry  28  may be coupled to input-output circuitry  86 . Input-output circuitry  86  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  86  may include input-output devices such as touch screens, buttons, joysticks, click wheels, scrolling wheels, touch pads, key pads, keyboards, light-emitting diodes and other status indicators, data ports, and audio components such as microphones and speakers. Input-output circuitry  86  may also include sensors. For example, input-output circuitry  86  may include an ambient light sensor, a proximity sensor, an accelerometer, and other sensor structures. Wireless communications circuitry and other communications circuitry in input-output circuitry  86  may allow device  10  to communicate with external equipment. 
     A cross-sectional side view of an illustrative configuration for display  14  of device  10  is shown in  FIG. 3 . As shown in  FIG. 3 , 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. 3 ) and passes through display pixel structures (display pixels  40  of  FIG. 2 ) in liquid crystal display layers  46  (sometimes referred to as a liquid crystal display module or liquid crystal display structures). This illuminates any images that are being produced by display pixels  40  of display  14  for viewing by a user. For example, backlight  44  illuminates images on display layers  46  that are being viewed by viewer  48  in direction  50 . The images that are displayed may include moving image content (e.g., video clips, etc.) and/or static image content (text, graphics, photographs, etc.). Control circuitry  28  may use display circuitry such as timing controller  34  and driver circuitry  62  and  38  to display content on display pixels  40  of display  14 . 
     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 structure 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 A). 
     Display layers  46  may form a liquid crystal display or may be used in forming displays of other types. In a liquid crystal display configuration, display layers  46  include a liquid crystal layer such a liquid crystal layer  52 . Liquid crystal layer  52  is sandwiched between display layers such as display layers  58  and  56 . Layers  56  and  58  are interposed between lower polarizer layer  60  and upper polarizer layer  54 . 
     Layers  58  and  56  are formed from transparent substrate layers such as clear layers of glass or plastic. Layers  56  and  58  are layers such as a thin-film transistor layer (e.g., a thin-film-transistor substrate such as a glass layer coated with a layer of thin-film transistor circuitry) and/or a color filter layer (e.g., a color filter layer substrate such as a layer of glass having a layer of color filter elements such as red, blue, and green color filter elements arranged in an array). Conductive traces, color filter elements, transistors, and other circuits and structures are 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  is 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  is 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, layer  58  may be a color filter layer and layer  56  may be a thin-film transistor layer. Layer  56  may, if desired, be a clear substrate or a substrate with a single color of color filter material (e.g., in configurations for display  14  in which display  14  is a monochrome display that displays monochrome images). 
     During operation of display  14  in device  10 , control circuitry  28  and timing controller  34  (e.g., one or more integrated circuits such as components  68  on printed circuit  66  of  FIG. 3  and/or other circuitry) is used to generate information to be displayed on display  14  (e.g., display data). The information to be displayed is conveyed from circuitry  68  to display driver circuitry such as one or more column driver integrated circuits  62  and gate driver circuitry on layer  58  using a signal path such as a signal path formed from conductive metal traces in printed circuit structures (shown as path  64  in  FIG. 3 ). 
     Display driver circuitry such as display driver integrated circuit(s)  62  of  FIG. 3  may be mounted on thin-film-transistor layer driver ledge  82  of thin-film transistor layer  58  or elsewhere in device  10 . 
     The printed circuit structures that are used in forming path  64  may include rigid printed circuit board material (e.g., fiberglass-filled epoxy material such as FR4 rigid printed circuit board material) and flexible printed circuit material (e.g., printed circuits formed from layers of polyimide or sheets of other flexible polymers). With one suitable arrangement, which is sometimes described herein as an example, path  64  may be formed from integrally connected flexible printed circuit material and rigid printed circuit board material. In this type of printed circuit, which is sometimes referred to as a rigid flex printed circuit board or “rigid flex,” one or more rigid printed circuit board regions have extending flexible tails. The rigid printed circuit board regions have multiple layers. The extending flexible tails are formed from a flexible subset of the layers in the rigid printed circuit board region. A rigid flex printed circuit may have one or more rigid printed circuit board areas and one or more sections of flexible printed circuit that are formed by extending a flexible subset of the layers of the rigid printed circuit board areas outwards from the rigid printed circuit board areas. 
       FIG. 4  is a diagram showing how display circuitry may be coupled to display layers such as thin-film transistor layer  58  using rigid flex communications paths. As shown in  FIG. 4 , rigid flex  90  may have one or more rigid printed circuit board portions such as rigid printed circuit board portions  90 - 2  and  90 - 4  and one or more flexible printed circuit portions that extend outwards from the rigid printed circuit board material such as flexible printed circuit portions  90 - 1  and  90 - 3 . Structures such as flexible portion  90 - 3  may help form path  64  (e.g., a path that crosses hinge axis  24 . 
     Integrated circuits for providing display control functions such as display timing controller integrated circuit  34  and/or other display control integrated circuits may be mounted on rigid printed circuit board portion  90 - 4  of rigid flex  90 . Integrated circuit  34  may be mounted on rigid printed circuit board portion  90 - 4  using anisotropic conductive film, solder joints, or other conductive structures. If desired, rigid printed circuit board portion  90 - 4  may be used as a substrate for other control circuits in device  10  besides display control circuits such as timing controller  34 . For example, rigid printed circuit board portion  90 - 4  may be used as a substrate for portions of control circuitry  28  of  FIG. 2  and input-output circuitry  86 . 
     Circuitry on rigid printed circuit board portion  90 - 4  may be directly coupled to a substrate such as a main logic board in base  12 B or other printed circuit on which control circuitry  28  and input-output circuitry  86  have been mounted. A board-to-board connector or other coupling mechanism may be used in coupling rigid printed circuit board portion  90 - 4  or a flexible printed circuit portion of rigid flex  90  to the substrate in base  12 B. Alternatively, or in addition to using direct coupling schemes, a flexible printed circuit jumper or other cable may be used to couple integrated circuits and other components on rigid printed circuit board portion  90 - 4  to a substrate such as a main logic board or other printed circuit. 
     Rigid printed circuit board portions of rigid flex  90  such as rigid printed circuit board portions  90 - 2  and  90 - 4  may have one or more layers of signal lines formed from patterned metal traces. For example, rigid printed circuit board portions  90 - 2  and  90 - 4  may contain two or more signal trace layers, three or more signal traces layers, may be four layer boards, 8 layer boards, or 10 layer boards, etc. Layers of dielectric printed circuit board material may separate the layers of signal traces. Particularly in scenarios in which flexible printed circuit portions  90 - 1  and  90 - 3  of rigid flex  90  contain a relatively small number of signal layers (e.g., when portions  90 - 1  and  90 - 3  are single-signal-line-layer flexible printed circuits), the use of multilayer printed circuit board material for forming rigid printed circuit board portions  90 - 2  and  90 - 4  can help enhance signal line density in the rigid printed circuit board portions  90 - 2  and  90 - 4  relative to the flexible printed circuit board portions. The use of relatively dense multilayer structures for forming rigid portions  90 - 2  and  90 - 4  can reduce the widths and lengths of board portions  90 - 2  and  90 - 4  and can therefore help minimize the amount of space that is consumed by rigid flex  90  within housing  12 . 
     As shown in  FIG. 4 , flexible printed circuit portions  90 - 1  may form a series of four tails (or more tails or fewer tails) that extend from rigid printed circuit board portion  90 - 2 . Tips  90 - 1 T of flexible printed circuit portions  90 - 1  may be attached to metal traces within liquid crystal display layers  46 . For example, tips  90 - 1 T may each contain metal signal lines that are coupled to mating metal signal lines in thin-film transistor layer  58 . Anisotropic conductive film, solder connections, or other suitable electrical connections may be used in coupling the signal lines in tips  90 - 1 T to corresponding signal lines on layer  58 . 
     Rigid printed circuit board portion  90 - 2  may have the shape of an elongated strip that runs along the edge of display layers such as thin-film transistor layer  58 . Rigid printed circuit board portion  90 - 2  of rigid flex  90  and flexible printed circuit portions  90 - 1 T of rigid flex  90  may be mounted within lid  12 A of housing  12 . 
     Flexible printed circuit portion  90 - 3  may extend between rigid printed circuit board portion  90 - 2  in lid  12 A and rigid printed circuit board portion  90 - 4  in base  12 B of housing  12 . Flexible printed circuit portion  90 - 3  may have the shape of a thin strip that lies within the center of device  10  (laterally midway between the left and right edges of device  10  as flexible printed circuit portion  90 - 3  passes through the hinge at the intersection between lid  12 A and base  12 B) or may have another shape and be located elsewhere in device  10 . In configurations of the type shown in  FIG. 4  in which flexible printed circuit portion  90 - 3  is located midway between the left and right edges of device  10 , antennas may be formed to the right and left of flexible printed circuit portion  90 - 3 . As an example, a first antenna such as antenna  92  may be located to the left of flexible printed circuit portion  90 - 3  and a second antenna such as antenna  94  may be formed to the right of flexible printed circuit portion  90 - 3 . 
     Flexible printed circuit portion  90 - 3  may be used in forming signal path  64  between integrated circuit  34  and the driver circuitry on thin-film transistor layer  58 . Flexible printed circuit portion  90 - 3  (e.g., the section of portion  90 - 3  that traverses hinge axis  24 ) may be flexed back and forth as lid  12 A is opened and closed relative to base  12 B. To prevent signal line cracking and other undesired damage to the metal traces of flexible printed circuit portion  90 - 3 , it may be desirable to form flexible printed circuit portion  90 - 3  using a single layer of patterned metal signal line traces. As shown in  FIG. 5 , for example, flexible printed circuit portion  90 - 3  (and, if desired, flexible printed circuit portions  90 - 1 ) may be formed from a single patterned layer of metal traces such as metal signal line layer  100 . Layer  100  may include differential pairs for carrying display data, power lines, and lines for carrying other control, data, and power signals. 
     Metal signal line layer  100  of flexible printed circuit portion  90 - 3  of rigid flex  90  may have dielectric layers such as layers  102 . Metal signal line layer  100  may be sandwiched between respective upper and lower layers  102 . Layers  102  may be formed from a dielectric such as polyimide or other flexible polymer. Electromagnetic shielding may be provided by incorporating upper and lower metal layers  104  onto the respective upper and lower surfaces of polymer layers  102 . For example, layers  104  may be silver layers or other metal layers that serve as electromagnetic interference shielding for metal signal line layer  100 . When a single-signal-line-layer flexible printed circuit is provided with opposing outer layers of shielding metal, the flexible printed circuit may sometimes be referred to as a double-shield-layer single-signal-line-layer flexible printed circuit. By providing shielding on the upper and lower surfaces of the flexible printed circuit portion of the rigid flex that traverses the area occupied by the antennas in device  10 , interference between signals generated by display  14  and signals associated with the operation of the antennas can be minimized. 
     The amount of stress that is induced in the traces of metal signal line layer  100  when portion  90 - 3  is bent may be minimized by aligning metal signal line layer  100  with neutral stress plane  106 . This may be accomplished by configuring the upper and lower layers on metal signal line layer  100  so that the amount of compressive stress in layer  100  that is produced by one set of layers is balanced by an equal amount of tensile stress in layer  100  being produced by the other set of layers. As an example, if portion  90 - 3  is bent downwards, tensile stress will be produced in the layers above layer  100  and compressive stress will be produced in the layers below layer  100 . By locating metal signal line layer  100  in neutral stress plane  106 , metal signal line layer  100  will be placed under neither tensile stress nor compressive stress as a result of the bending. 
     With one illustrative configuration, neutral stress plane  106  can be aligned with metal signal line layer  100  by forming layers  102  above and below metal signal line layer  100  from polyimide or other polymer layers of equal thickness and by forming layers  104  above and below layers  102  using silver or other metal coating layers of equal thickness. 
       FIG. 5  shows how the flexible layers of flexible printed circuit portion  90 - 3  extend outwardly (to the left in the orientation of  FIG. 5 ) from the larger number of layers used in forming rigid printed circuit board portion  90 - 4 . Additional printed circuit board layers such as additional layers of signal lines and additional rigid printed circuit board dielectric can be provided above and below the flexible printed circuit layers. These additional layers in rigid printed circuit portion  90 - 4  are shown as layers  107  in the example of  FIG. 5 . 
     As shown in  FIG. 4 , flexile printed circuit portion  90 - 3  can extend as a flexible tail from both rigid portion  90 - 2  and from rigid portion  90 - 2 . Similarly, flexible printed circuit portions  90 - 1 T may extend in an integral fashion from rigid printed circuit portion  90 - 2 . 
       FIG. 6  is a cross-sectional side view of a portion of device  10  in the vicinity of hinge axis  24  when device  10  is in a closed lid configuration. As shown in  FIG. 6 , display control integrated circuits such as timing controller integrated circuit  34  may be mounted on the lower surface of rigid printed circuit board portion  90 - 4  of rigid flex  90  (in the orientation of  FIG. 6 ). Flexible printed circuit portion  90 - 3  of rigid flex  90  may bridge hinge axis  24  between base  12 B and lid  12 A. For example, a single flexible printed circuit segment such as portion  90 - 3  may traverse the hinge axis a single time. Flexible printed circuit portion  90 - 3  may be formed from a thin flexible structure of the type described in connection with  FIG. 5  to allow flexible printed circuit portion  90 - 3  to bend without damage, thereby accommodating relative movement between lid  12 A and base  12 B. 
     Display driver circuitry such as column driver integrated circuit(s)  62  may be mounted on ledge portion  82  of thin-film transistor layer  58  (e.g., column driver integrated circuit(s)  62  may be mounted so as to face downward in the orientation of  FIG. 6 ). Flexible printed circuit portion  90 - 1  of rigid flex  90  may extend between rigid printed circuit board portion  90 - 2  of rigid flex  90  and metal traces on ledge  82  of thin-film transistor layer  58 . Flexible printed circuit portion  90 - 1  may be sufficiently flexible to form a 180° bend, as shown in  FIG. 6 . Conductive bonding material  96  such as anisotropic conductive film or other conductive structures may be used in coupling the metal traces of flexible printed circuit portion  90 - 1  of rigid flex  90  to the traces on thin-film transistor substrate  58 . 
     Rigid printed circuit board portion  90 - 2  of rigid flex  90  may contain multiple layers of metal signal lines (e.g., two or more, four or more, eight or more, or ten or more). By incorporating a sufficient number of metal signal line layers in rigid printed circuit board portion  90 - 2 , a relatively large number of interconnect paths can be formed in rigid printed circuit board portion  90 - 2  while minimizing board width W. By minimizing board width W, more room may be made available within lid  12 A to accommodate backlight unit  42  in display  14 . 
       FIG. 7  is a cross-sectional side view of the hinge portion of device  10  where lid  12 A has been placed in an open configuration. As shown in  FIG. 7 , flexible printed circuit portion  90 - 3  of rigid flex  90  may move in direction  202  from a first position such as position  200 A to a second position such as position  200 B to accommodate the relative movement between lid  12 A and base  12 B. By using a single-signal-line-layer flexible printed circuit (sometimes referred to as “single flex”) and by using a configuration in which the neutral stress plane of the flexible printed circuit is aligned with the single layer of signal lines, stress in the signal lines of flexible printed circuit portion  90 - 3  may be minimized during lid movement relative to base  12 B. This can help avoid damage to the signal lines in flexible printed circuit portion  90 - 3  due to stress-induced cracks, thereby preventing failure of rigid flex  90 . 
     If desired, rigid flex  90  may have a different number of flexible printed circuit portions, may have one or more flexible printed circuit portions that traverse the hinge between lid  12 A and base  12 B in one or more different locations from the center location of flexible printed circuit portion  90 - 3  in  FIG. 4 , or may have a different number of rigid printed circuit board portions. Flexible printed circuits (i.e., printed circuits without any rigid printed circuit board regions) may also be used for distributing signals between control and display circuitry in base  12 B and display driver circuitry for display  14  in lid  12 A, if desired. 
     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: 20130815
Publication Date: 20171031
Grant Date: 20171031
Priority Date: 20130815
Inventors: POSNER BRYAN W.
MATHEW DINESH C.
BENSON ERIC L.
GOMEZ JASON N.
QI JUN
CAO ROBERT Y.
YIN VICTOR H.
LIGTENBERG CHRISTIAAN A.
LIN WEY-JIUN
Assignee: APPLE INC
CPC Classifications: [{"code": "G02F1/13306", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/1368", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K1/148", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1683", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/1681", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1637", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K1/148", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1681", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1683", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K2201/10136", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K2201/10136", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/13306", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K2201/10136", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/1368", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K1/148", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1637", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1683", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/1681", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 51301356