PATENT DOCUMENT

Publication Number: US-9103512-B2
Application Number: US-201313770169-A
Country: US
Kind Code: B2

Title: Electronic device with display backlight alignment structures

Abstract:
Electronic devices may include displays having backlight structures and display layers. The display layers may include alignment features. The backlight structure may include alignment features. The alignment features on the backlight structures may include transparent portions of the backlight structures. The alignment features on the display layers may include alignment marks that are visible through the transparent portions of the backlight structures. The transparent portions of the backlight structures may include openings that extend from a first surface of the backlight structures to an opposing second surface of the backlight structures. The openings may be filled by transparent members formed from plastic or glass. The transparent members may include additional alignment marks. The transparent members may include lensing portions that magnify the alignment marks on the display layers when viewed through the lensing portions.

Claims:
What is claimed is: 
     
       1. A display, comprising:
 backlight structures that generates light for the display; and 
 at least one display layer that controls emission of the light from the display, wherein the backlight structures comprise a transparent portion, wherein the at least one display layer comprises an alignment mark that is visible through the transparent portion of the backlight structures, and wherein the transparent portion comprises a material selected from the group consisting of: plastic and glass. 
 
     
     
       2. The display defined in  claim 1  wherein the transparent portion of the backlight structures comprises an opening in the backlight structures that extends from a first surface of the backlight structures to an opposing second surface of the backlight structures. 
     
     
       3. The display defined in  claim 2 , further comprising a transparent member in the opening. 
     
     
       4. The display defined in  claim 3  wherein the transparent member comprises glass. 
     
     
       5. The display defined in  claim 3  wherein the transparent member comprises plastic. 
     
     
       6. The display defined  3 , further comprising an additional alignment mark on the transparent member that is aligned with the alignment mark on the at least display layer when viewed through the transparent member. 
     
     
       7. The display defined in  claim 6  wherein the additional alignment mark on the transparent member comprises an embedded alignment mark that is formed within the transparent member. 
     
     
       8. The display defined in  claim 1  wherein the at least one display layer comprises a color filter layer and wherein the alignment mark that is visible through the transparent portion of the backlight structures comprises at least one alignment mark on the color filter layer. 
     
     
       9. The display defined in  claim 1  wherein the at least one display layer comprises a thin-film transistor layer and wherein the alignment mark that is visible through the transparent portion of the backlight structures comprises at least one alignment mark on the thin-film transistor layer. 
     
     
       10. The display defined in  claim 1  wherein the alignment mark that is visible through the transparent portion of the backlight structures comprises a linear alignment mark that extends along an edge of the at least one display layer. 
     
     
       11. The display defined in  claim 10  wherein the linear alignment mark is located at a known distance from the edge of the at least one display layer. 
     
     
       12. A display, comprising:
 a backlight unit that generates display light for the display; and 
 display layers that control emission of the display light from the display, wherein the backlight unit comprises at least one lens and wherein the display layers comprise an alignment feature that is magnified by the lens when viewed through the lens. 
 
     
     
       13. The display defined in  claim 12  wherein the backlight unit includes an opening that extends from a first surface of the backlight unit to an opposing second surface of the backlight unit and wherein the at least one lens comprises a lensing portion that is formed within the opening. 
     
     
       14. The display defined in  claim 13  wherein the lens further comprises a conical transparent member in the opening. 
     
     
       15. The display defined in  claim 13  wherein the lens further comprises a cylindrical transparent member in the opening. 
     
     
       16. The display defined in  claim 12  wherein the backlight unit includes an opening that extends from a first surface of the backlight unit to an opposing second surface of the backlight unit and wherein the at least one lens comprises a lensing portion that extends from the opening beyond the first surface of the backlight unit. 
     
     
       17. The display defined in  claim 16  wherein the backlight unit further comprises a light-emitting zone, and wherein the lens is formed outside of the light-emitting zone. 
     
     
       18. The display defined in  claim 16  wherein the backlight unit further comprises at least one additional lens and wherein the display layers comprise at least one additional alignment feature that is magnified by the at least one additional lens when viewed through the at least one additional lens. 
     
     
       19. A method for assembling a display for an electronic device using an assembly system having a camera, wherein the display comprises backlight structures having transparent portions and display layers having alignment features, the method comprising:
 determining locations of the alignment features on the display layers by viewing the alignment features through the transparent portions of the backlight structures using the camera, wherein the transparent portions comprise polymer material; and 
 with the assembly system, aligning the backlight structures with the display layers using the determined locations of the alignment features. 
 
     
     
       20. The method defined in  claim 19  wherein the backlight structures further comprise alignment marks on the transparent portions and wherein aligning the backlight structures with the display layers using the determined locations of the alignment features comprises:
 determining locations of the alignment marks on the transparent portions of the backlight structures; and 
 optically tracking the locations of the alignment marks and the locations of the alignment features while moving the backlight structures. 
 
     
     
       21. The method defined in  claim 19  wherein aligning the backlight structures with the display layers using the determined locations of the alignment features comprises:
 determining locations of the transparent portion of the backlight structures. 
 
     
     
       22. The method defined in  claim 21  wherein aligning the backlight structures with the display layers using the determined locations of the alignment features further comprises:
 determining a location of a center point of the backlight structures using the determined locations of the transparent portions; and 
 determining a location of a center point of the display layers using the determined locations of the alignment features. 
 
     
     
       23. The method defined in  claim 22  wherein aligning the backlight structures with the display layers using the determined locations of the alignment features further comprises:
 aligning the center point of the backlight structures with the center point of the display layers by moving the backlight structures.

Description:
This application claims priority to U.S. provisional patent application No. 61/707,775 filed Sep. 28, 2012, which is hereby incorporated by reference herein in its entirety. 
    
    
     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, weight, electrical grounding, robustness, ease of assembly, and light-tightness are often important considerations in designing electronic devices. If care is not taken, displays may be bulky, may exhibit undesired light reflections, or may be prone to damage during a drop event. The housing of an electronic device can be adjusted to accommodate a bulky display with large borders, but this can lead to undesirable enlargement of the size and weight of the housing and unappealing device aesthetics. 
     It would therefore be desirable to be able to provide improved ways to provide displays for electronic devices. 
     SUMMARY 
     An electronic device may be provided with a display. The display may have display layers for displaying images. Backlight structures may be included in the display. The backlight structures may generate light that illuminates the display layers in the display that are displaying an image for a user. 
     The backlight structures and the display layers may include alignment features that are used to align the backlight structures to the display layers during assembly of the electronic device. During assembly, the display layers may be attached to a transparent cover layer for the device. The backlight structures may be aligned with the display layers using the alignment features on the backlight structures and the alignment features on the display layers. 
     The alignment features on the display layers may include alignment marks that are screen printed, etched, carved, embedded or otherwise formed on a transparent substrate layer such as a color filter glass layer or a thin-film transistor glass layer of the display. The alignment features on the backlight structures may include an opening in a peripheral plastic support structure of the backlight structures. 
     The opening may extend from a surface of the plastic support structure to an opposing surface of the support structure so that the alignment features on the display layers can be viewed through the openings by a camera in a display assembly system. 
     The opening may be empty or may be filled with a transparent filler material such as plastic or glass. In one suitable example, the plastic support structure may be formed in a two-shot molding process in which a first shot of plastic is used to form the support structure and a second shot of transparent plastic is used to form a transparent member. 
     The transparent member may include alignment marks on a surface of the transparent member or embedded within the transparent member. 
     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 illustrative display layers and backlight structures in accordance with an embodiment of the present invention. 
         FIG. 7  is a cross-sectional side view of an illustrative display during assembly showing how an assembly system may use alignment structures on backlight structures and on display layers to align the backlight structures to the display layers in accordance with an embodiment of the present invention. 
         FIG. 8  is a top view of illustrative display layers with alignment structures located in an inactive area of the display in accordance with an embodiment of the present invention. 
         FIG. 9  is a perspective view of illustrative display layers with alignment structures on a top surface of a color filter layer in accordance with an embodiment of the present invention. 
         FIG. 10  is a perspective view of illustrative display layers with alignment structures on a bottom surface of a color filter layer in accordance with an embodiment of the present invention. 
         FIG. 11  is a perspective view of illustrative display layers with alignment structures on a top surface of a thin-film transistor layer in accordance with an embodiment of the present invention. 
         FIG. 12  is a perspective view of illustrative display layers with alignment structures on a bottom surface of a thin-film transistor layer in accordance with an embodiment of the present invention. 
         FIG. 13  is a top view of illustrative display layers showing how alignment structures on the display layers may include cross-hairs formed on the display layers in accordance with an embodiment of the present invention. 
         FIG. 14  is a top view of illustrative display layers showing how alignment structures on the display layers may include encircled cross-hairs formed on the display layers in accordance with an embodiment of the present invention. 
         FIG. 15  is a top view of illustrative display layers showing how alignment structures on the display layers may include more than two crossed lines formed on the display layers in accordance with an embodiment of the present invention. 
         FIG. 16  is a top view of illustrative display layers showing how alignment structures on the display layers may include alignment rings with various radii formed on the display layers in accordance with an embodiment of the present invention. 
         FIG. 17  is a top view of illustrative display layers showing how alignment structures on the display layers may include cross-hatched linear distance indicators formed on the display layers in accordance with an embodiment of the present invention. 
         FIG. 18  is a perspective view of illustrative backlight structures with alignment structures located outside of the light-emitting zone of the backlight structures in accordance with an embodiment of the present invention. 
         FIG. 19  is a perspective view of illustrative backlight structure alignment features formed from an opening in the backlight structures in accordance with an embodiment of the present invention. 
         FIG. 20  is a perspective view of illustrative backlight structure alignment features formed from an opening in the backlight structures that is filled with a transparent member in accordance with an embodiment of the present invention. 
         FIG. 21  is a perspective view of an illustrative transparent member of the type shown in  FIG. 20  showing how the transparent member may be provided with alignment marks on a top surface in accordance with an embodiment of the present invention. 
         FIG. 22  is a perspective view of an illustrative transparent member of the type shown in  FIG. 20  showing how the transparent member may be provided with alignment marks on a bottom surface in accordance with an embodiment of the present invention. 
         FIG. 23  is a perspective view of an illustrative transparent member of the type shown in  FIG. 20  showing how the transparent member may be provided with alignment marks that are embedded within the transparent member in accordance with an embodiment of the present invention. 
         FIG. 24  is a perspective view of an illustrative transparent member of the type shown in  FIG. 20  showing how the transparent member may be provided with circular alignment marks having various radii in accordance with an embodiment of the present invention. 
         FIG. 25  is a perspective view of an illustrative transparent member of the type shown in  FIG. 20  showing how the transparent member may include a lens in accordance with an embodiment of the present invention. 
         FIG. 26  is a perspective view of an illustrative lens of the type shown in  FIG. 25  showing how the lens may include a conical portion and a lensing portion that is formed below an inner surface of the display backlight structures in accordance with an embodiment of the present invention. 
         FIG. 27  is a perspective view of an illustrative lens of the type shown in  FIG. 25  showing how the lens may include a lensing portion that is formed in a cylindrical opening and below an inner surface of the display backlight structures in accordance with an embodiment of the present invention. 
         FIG. 28  is a perspective view of an illustrative lens of the type shown in  FIG. 25  showing how the lens may include a conical portion and a lensing portion that extends above an inner surface of the display backlight structures in accordance with an embodiment of the present invention. 
         FIG. 29  is a perspective view of an illustrative lens of the type shown in  FIG. 25  showing how the lens may include a cylindrical portion and a lensing portion that extends above an inner surface of the display backlight structures in accordance with an embodiment of the present invention. 
         FIG. 30  is a top view of illustrative display layers having alignment marks showing how the alignment marks may be used to determine a center point of the display layers in accordance with an embodiment of the present invention. 
         FIG. 31  is a top view of illustrative display layers and backlight structures during alignment operations showing how alignment marks on the display layers may be visible to an assembly system through transparent portions of the backlight structures in accordance with an embodiment of the present invention. 
         FIG. 32  is a flow chart of illustrative steps involved in assembling a display for an electronic device using alignment features on display layers and alignment features on backlight structures in accordance with an embodiment of the present invention. 
         FIG. 33  is a flow chart of illustrative steps involved in aligning display layers and backlight structures as described in  FIG. 32  in accordance with an embodiment of the present invention. 
         FIG. 34  is a flow chart of illustrative steps involved in aligning center points of display layers and backlight structures as described in  FIG. 32  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 with an opening to accommodate button  26  (as an example). 
     Peripheral portions of display  14  may be provided with an opaque masking layer. As shown in  FIGS. 1 ,  2 , and  3 , display  14  may be characterized by a central active region such as active region AA in which an array of display pixels is used in displaying information for a user. Active region AA may be surrounded by an inactive region such as inactive border region IA. Active region AA may have a rectangular shape bordered by rectangular line  21 . Inactive region IA may have a rectangular ring shape that surrounds active region AA (as an example). The underside of the display cover layer in inactive region IA may be covered with an opaque masking layer such as a layer of black ink (e.g., a polymer filled with carbon black). The opaque masking layer may help hide components in the interior of device  10  in inactive region IA from view by a user. 
     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 or cast 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. 
     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 or other portion of a display may be used as the outermost (or nearly outermost) layer in display  14 . 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 one or more layers of touch-sensitive components such as touch-sensitive layers  47  that are attached to a cover layer such as cover layer  49 . Cover layer  49  may be formed from a sheet of rigid or flexible transparent material such as glass or plastic. 
     Touch-sensitive layers  47  may be attached to cover layer  49  using an adhesive material such as optically clear adhesive (OCA)  43 . Adhesive  43  may be a liquid adhesive, light-cured adhesive, pressure-sensitive adhesive or other suitable adhesive. Touch-sensitive layers  47  may include touch-sensor components such as an array of capacitive touch-sensor electrodes formed from transparent materials such as indium tin oxide. 
     Display  14  may include display layers such as layers  46  for generating images to be displayed on display  14 . Display layers  46  may include polarizer layers, color filter layers, transistor layers, adhesive layers, layers of liquid crystal material, or other layers for generating display images. Display layers  46  may be attached to touch-sensitive layers  47  using adhesive such as optically clear adhesive  45 . Adhesive  45  may be a liquid adhesive, light-cured adhesive, pressure-sensitive adhesive or other suitable adhesive. 
     Display layers  46  may use light generated by light-generating structures such as backlight structures  42  to form images to be viewed by a user of device  10 . Backlight structures  42  may include light-generating components such as light-emitting diodes, light guiding structures, reflective structures, optical films, etc. Backlight structures  42  may be attached to display layers  46  or may be mounted adjacent to layers  46  by attaching backlight structures  42  to one or more structural members. 
     A cross-sectional side view of an illustrative configuration that may be used for display layers  46  and backlight structures  42  of display  14  (e.g., for display layers  46  and backlight structures  42  of the display of  FIG. 5 , or other suitable display) is shown in  FIG. 6 . As shown in  FIG. 6 , display  14  may include backlight structures such as backlight unit  42  for producing backlight  44 . During operation, backlight  44  travels outwards (vertically upwards in dimension Z in the orientation of  FIG. 6 ) 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 ) to laminated to a cover layer such as cover  49  of  FIG. 5 . 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 . If desired, upper polarizer layer  54  may be attached to an outer cover layer such as cover layer  49  ( FIG. 5 ). 
     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, layer  58  may be a color filter layer and layer  56  may be a thin-film transistor 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. 6 ) may be used to generate information to be displayed on display  14  (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  58 . 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). However, these examples are merely illustrative. If desired printed circuits  64  and  66  may be formed from a combination of rigid and flexible printed circuit layers (e.g., printed circuit  66  may be formed from a rigid printed circuit board with a layer of flexible printed circuitry that extends from an edge of printed circuit  66  to form flexible printed circuitry  64  that attaches to thin-film-transistor layer  58 ). 
     Backlight structures  42  may include a backlight 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 in dimensions X and Y 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 or other light-scattering structures. 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 in direction Z 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 in the X-Y plane of  FIG. 6 , optical films  70  and reflector  80  may have a matching rectangular footprint. 
     During assembly of display  14 , backlight structures  42  may be aligned with display layers  46  as shown in  FIG. 7 . A system such as assembly system  100  for assembling display  14  and, if desired, other portions of device  10 , may include one or more cameras  104 , actuating members  106 , and computing equipment  102  for controlling cameras  104  and actuating members  106 . 
     Actuating member  106  may be used to hold and move backlight structures  42  based on alignment data obtained using cameras  104 . Cameras  104  may view alignment features such as alignment marks  108  on display layers  46  through alignment features such as transparent portions  120  of backlight structures  42  along directions  111 . Actuating members  106  may move backlight structures  42  in a direction parallel to the x-y plane of  FIG. 4  until alignment marks  108  on display layers  46  are in a suitable (aligned) position with respect to transparent portions  120  of backlight structures  42 . 
     Actuating members  106  may also move backlight structures along direction  116  (i.e., parallel to the z-direction of  FIG. 4 ) into position adjacent to display layers  46 . Following alignment and placement of backlight structures  42 , backlight structures  42  may be secured in housing  12  by attaching backlight structures  42  to display layers  46  using an optically clear adhesive or by attaching backlight structures  42  mechanically to cover layer  49  and/or housing  12  (see, e.g.,  FIG. 1 ) using screws, adhesive, clips, or other attachment members (as examples). 
     Alignment system  100  may use alignment marks  108  and transparent portions  120  of backlight structures  42  to alight a light-emitting zone (LEZ) of the backlight structures with the active area (AA) of the display layers. Alignment system  100  may use alignment marks  108  and transparent portions  120  of backlight structures  42  to prevent edges  112  of extended portions  42 E of backlight structures  42  from colliding with edge portions  110  of display layers  46  during display assembly operations (as edges  112  move in direction  116  along paths  114 ). 
     Display  14  may include an opaque masking layer such as layer  118  that at least partially covers inactive edge portions of the display surrounding active area AA. The underside of the display cover layer  49  in inactive region IA may be covered with opaque masking layer  118 . Layer  118  may be formed from an opaque material such as a layer of black ink (e.g., a polymer filled with carbon black). The opaque masking layer may help hide components in the interior of device  10  in inactive region IA from view by a user such as viewer  48  viewing display  14  in a direction such as direction  50 . However, layer  118  may also make it difficult to view alignment marks  108  on display layers  118  through cover layer  49 . For this reason, transparent portions  120  of backlight structures  42  may be used to align backlight structures  42  to display layer  46  during assembly operations. 
       FIG. 8  is a top view of display layers  46  showing how alignment structures such as alignment marks  108  may be located in inactive area IA. As shown in  FIG. 8 , alignment marks  108  may include alignment marks located near corners of display layers  46  and/or alignment marks located along edges of display layers  46 . Alignment marks  108  may include alignment marks that indicate points on display layers  46  (e.g., cross hairs, etc.) or alignment marks that indicate lines on display layers  46  (e.g., elongated lines that represent distances from edges of display layers or from edges of active area AA). 
       FIGS. 9 ,  10 ,  11 , and  12  show various locations within display layers  46  of display  14  at which alignment marks  108  may be formed. As shown in  FIG. 9  alignment marks  108  may be formed on top surface  130  of color filter layer  56 . As shown in  FIG. 10  alignment marks  108  may be formed on bottom surface  132  of color filter layer  56 . As shown in  FIG. 11  alignment marks  108  may be formed on top surface  134  of thin-film transistor layer  58 . As shown in  FIG. 12  alignment marks  108  may be formed on bottom surface  136  of thin-film transistor layer  58 . 
       FIGS. 13 ,  14 ,  15 , and  16 , show various examples of alignment marks that may be used to indicate a point on display layers  46 . As shown in  FIG. 13 , alignment marks  108  may be cross hairs that indicate the location of point  140  on display layers  46 . Point  140  may be located at a specific, known distance from other alignment marks  108  or from a center point on display layers  46 . 
     As shown in  FIG. 14 , alignment marks  108  may be encircled cross hairs that indicate the location of point  140 . As shown in  FIG. 15 , alignment marks  108  may be encircled cross hairs having more than two crossing lines that indicate the location of point  140 . As shown in  FIG. 16 , alignment marks  108  may be a series of circular marks that indicate the location of point  140 . In the example of  FIG. 16 , circular alignment marks may have known radii such as radii R1, R2, and R3. Radii R1, R2, and R3 may indicate distances from point  140  and may be used by system  100  to determine the accuracy of the alignment of backlight structures  42  with display layers  46  during display assembly operations. The alignment marks of  FIGS. 13 ,  14 ,  15 , and  16  are merely illustrative. Alignment marks may be used that have any suitable shape or pattern such as one or more combinations of the alignment marks of  FIGS. 13 ,  14 ,  15 , and  16 . 
       FIG. 17  is a top view of display layers  46  showing how alignment structures  108  may be formed from elongated linear distance indicators. In the example of  FIG. 17 , alignment marks  108  include three lines along each edge of display layers  46  that extend in a direction parallel to that edge. Each linear extended alignment mark may include one or more cross hatches  146  that help identify a particular alignment mark. 
     Alignment marks  108  that are formed along top edge  142  may be used to indicate distances such as distances DET1, DET2, and DET3 from top edge  142 . However, this is merely illustrative. Alignment marks  108  along top edge  142  may be used to indicate distances such as distances DAT1, DAT2, and DAT3 from active area AA. Alignment marks  108  that are formed along side edge  144  may be used to indicate distances such as distances DEE1, DEE2, and DEE3 from side edge  144 . However, this is merely illustrative. Alignment marks  108  along side edge  144  may be used to indicate distances such as distances DAE1, DAE2, and DAE3 from active area AA. 
     Actuating members  106  of system  100  (see  FIG. 7 ) may be used to move backlight structures  42  until one or more features and/or alignment structures on backlight structures  42  are aligned with one of the linear alignment marks  108  on display layers  46 . If desired, display layers  46  may include linear extended alignment marks of the type shown in  FIG. 17  and point-indicating alignment marks of the types shown in  FIGS. 13-16  that may be used in combination during display assembly operations. 
       FIG. 18  is a perspective view of backlight structures  42  showing how alignment structures  120  may be formed from transparent portions of backlight structures  42  that are located outside of the light-emitting zone of the backlight structures. As shown in  FIG. 18 , transparent portions  120  may extend from inner surface  150  to outer surface  152  of backlight structures  42 . Transparent portions  120  may be openings in backlight structures  42 . Openings in backlight structures  42  may be formed by mechanical or laser drilling (as examples) holes in a peripheral plastic portion of structures  42 . 
     Transparent portions  120  may be openings that are substantially empty or openings that are filled with a transparent member such as plastic or glass. Transparent portions  120  that are formed from openings that are filled with transparent members may include alignment marks on the transparent members. 
       FIG. 19  is a perspective view of backlight structures  42  showing how transparent portions  120  may be formed from an opening such as hole  156  in the backlight structures. 
       FIG. 20  is a perspective view of backlight structures  42  showing how transparent portions  120  may be filled by transparent member  158 . Transparent member  158  may be formed from plastic, glass or other transparent material. 
     In one suitable configuration that is sometimes discussed herein as an example, transparent member  120  and surrounding portions  159  of backlight structures  42  may be formed in a multi-shot molding process. For example, portion  159  may be formed from a shot of opaque plastic and transparent member  158  may be formed from a shot of transparent plastic. However, this is merely illustrative. If desired, transparent members  158  may be formed separately from backlight structures  42  and placed into openings such as openings  156  formed in backlight structures  42 . 
       FIGS. 21 ,  22 ,  23 , and  24  are perspective views of transparent members  158  showing how alignment marks of various types may be formed at various locations on transparent members  158 . 
     As shown in  FIG. 21 , alignment marks  160  may be formed on a top surface of transparent member  158  (i.e., a surface that is formed at or near surface  150  of backlight structures  42 ). As shown in  FIG. 22 , alignment marks  160  may be formed on a bottom surface of transparent member  158  (i.e., a surface that is formed at or near surface  152  of backlight structures  42 ). As shown in  FIG. 23 , alignment marks  160  may be embedded within transparent member  158 . 
     In the examples of  FIGS. 21 ,  22 , and  23 , alignment marks are formed from cross hairs. However, this is merely illustrative. Any suitable alignment marks may be formed on transparent members  158 . In the example of  FIG. 24 , alignment marks  160  are formed from concentric circular marks having known radii such as radii RA, RB, and RC. Alignment marks  160  on transparent members  158  may be aligned with alignment marks  108  on display layers  46  during display assembly operations. Radii RA, RB, and RC may be equal to, or proportional to radii R1, R2, and R3 of  FIG. 16 . 
     Alignment marks  160  that are formed on a surface of transparent member  158  may be screen printed, etched, carved, embedded or otherwise formed on a surface of member  158 . Alignment marks that are embedded within transparent member  158  may be formed from a material such as metal that is embedded with a transparent material such as plastic or glass when the transparent material is in a liquid form (e.g., during a multi-shot molding process). 
       FIG. 25  is a perspective view of a portion of backlight structures  42  showing how transparent member  158  may be formed in the shape of a lens. Providing backlight structures with alignment features formed from transparent members in the shape of a lens may help magnify alignment marks such as marks  108  on display layers  46  during display assembly operations, thereby helping facilitate the alignment of backlight structures  42  with display layers  46 . 
     As shown in  FIGS. 26 and 27 , transparent member  158  may include a lensing portion  170  having an innermost surface that is formed at or below inner surface  150  of backlight structures  42 . In the example of  FIG. 26 , transparent portion  158  includes lensing portion  170  formed over a transparent conical portion  172 . However, this is merely illustrative. As shown in  FIG. 27 , lensing portion  170  may be formed over a cylindrical transparent portion  174 . If desired, cylindrical transparent portion  174  may be an empty opening in backlight structures  42 . However, if desired, cylindrical transparent portion  174  may be formed form transparent material such as plastic or glass. 
     As shown in  FIGS. 28 and 29 , transparent member  158  may include a lensing portion  170  having an innermost surface that extends above inner surface  150  of backlight structures  42 . In the example of  FIG. 28 , transparent portion  158  includes lensing portion  170  formed over a transparent conical portion  172 . However, this is merely illustrative. As shown in  FIG. 29 , lensing portion  170  may be formed over a cylindrical transparent portion  174 . If desired, cylindrical transparent portion  174  may be an empty opening in backlight structures  42 . However, if desired, cylindrical transparent portion  174  may be formed form transparent material such as plastic or glass. 
     During assembly of device  10  and/or display  14 , system  100  ( FIG. 7 ) may be used to align backlight structures  42  to display layers  46 . System  100  may use cameras  104  to determine the locations of alignment features on backlight structures  42  and alignment features on display layers  46 . System  100  may align the alignment features on backlight structures  42  with the alignment features on display layers  46 . However, this is merely illustrative. System  100  may determine a center point on backlight structures  42  using transparent portions  12  and a center point on display layers  46  using marks  108  and align the backlight structures with the display layers by aligning the determined center point of the display layers with the determined center point of the backlight structures. 
       FIG. 30  is a top view of display layers  46  showing how alignment marks  108  may be arranged at various know distances center point  180  of display layers  46 . System  100  may use cameras  104  to determine the location of marks  108  by viewing marks  108  through transparent portions of structures  42  and use the determined locations of alignment marks  108  and the known distances to point  180  to determine the location of center point  180 . 
     As shown in  FIG. 31  transparent portions  120  of backlight structures  42  may be arranged at various known distances from center point  182  of backlight structures  42 . During display assembly operations, system  100  may view alignment marks  108  through transparent portions  120  as shown in  FIG. 31  and determine the location of center point  180  using alignment features  108  and determine center point  182  using the determined locations and known distances from point  182  of portions  120 . System  100  may then use actuating members  106  to move backlight structures  42  until center point  182  is aligned with center point  180 . 
     Illustrative steps involved in performing display assembly operations using a system of the type shown in  FIG. 7  are shown in  FIG. 32 . 
     At step  200 , the positions of backlight structure alignment features such as transparent portions  120  on backlight structures  42  may be determined. Determining the positions of the backlight structure alignment features may include locating the backlight structure alignment features using cameras  104  and computing equipment  102 . 
     At step  202 , the positions of display layer alignment features such as alignment marks  108  on display layers  46  may be determined. Determining the positions of the display layer alignment features may include locating the display layer alignment features using cameras  104  and computing equipment  102 . 
     At step  204 , system  100  may align light-emitting zone (LEZ) of backlight structures  42  with active area AA of display layers  46  using the determined positions of the backlight structure alignment features and the display layer alignment features. Aligning the light-emitting zone (LEZ) of backlight structures  42  with active area AA of display layers  46  using the determined positions of the backlight structure alignment features and the display layer alignment features may include aligning the respective alignment features or may include aligning center positions of the display layers and the backlight structures. 
     Illustrative steps involved in aligning light-emitting zone (LEZ) of backlight structures  42  with active area AA of display layers  46  using the determined positions of the backlight structure alignment features and the display layer alignment features as described in connection with step  204  of  FIG. 31  by aligning the respective alignment features are shown in  FIG. 32 . 
     At step  210 , the backlight structure alignment features may be aligned with the display layer alignment features by, for example, optically tracking the relative positions of the respective alignment features (e.g., using cameras  104 ) while moving backlight structures  42  (e.g., using actuating member  106 ). 
     Illustrative steps involved in aligning light-emitting zone (LEZ) of backlight structures  42  with active area AA of display layers  46  using the determined positions of the backlight structure alignment features and the display layer alignment features as described in connection with step  204  of  FIG. 31  by aligning center positions of the display layers and the backlight structures are shown in  FIG. 32 . 
     At step  220 , system  100  may determine the location of a center point such as center point  182  of backlight structures  42  (e.g., by determining relative locations of alignment features such as transparent portions  120  of the backlight structures). 
     At step  222 , system  100  may determine the location of a center point such as center point  180  of display layers  46  (e.g., by determining relative locations of alignment features such as alignment marks  108  of the backlight structures). 
     At step  224 , system  100  may align the determined center point of the display layers with the determined center point of the backlight structures (e.g., by moving the backlight structures using actuating members  106  until center point  182  is aligned with center point  180 ). 
     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: 20130219
Publication Date: 20150811
Grant Date: 20150811
Priority Date: 20120928
Inventors: FRANKLIN JEREMY C.
GIBBS KEVIN D.
QIAN AMY
RAFF JOHN
AI JIANG
Assignee: APPLE INC
CPC Classifications: [{"code": "G02F1/1333", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133608", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1637", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133308", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1626", "inventive": true, "first": false, "tree": "[]"}, {"code": "Y10T29/49769", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/1333", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1643", "inventive": true, "first": false, "tree": "[]"}, {"code": "Y10T29/49769", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1637", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1643", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133308", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1626", "inventive": true, "first": true, "tree": "[]"}, {"code": "F21V17/10", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02F2001/133325", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F2001/133354", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133308", "inventive": true, "first": false, "tree": "[]"}, {"code": "Y10T29/49769", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133608", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1626", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1643", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1637", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/1333", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F2001/133322", "inventive": false, "first": false, "tree": "[]"}, {"code": "F21V17/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "F21S2/00", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02F1/133354", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133354", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133322", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133325", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133322", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133325", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 50384997