PATENT DOCUMENT

Publication Number: US-8638549-B2
Application Number: US-86274810-A
Country: US
Kind Code: B2

Title: Electronic device display module

Abstract:
Electronic devices may have housings. A housing may contain a display on its front face and a rear plate such as a plate formed from glass on its rear face. A peripheral housing member may surround the display and rear plate. An antenna may be formed in the peripheral housing member. The rear plate may be formed from laminated layers including a light guide layer. Device hinges may include hinge structures that are integral to the peripheral housing member. A logo may be formed by coating the rear plate with a patterned masking layer. Display structures for the display and the rear plate may be mounted to opposing sides of a shelf portion of the peripheral housing member. The rear plate may be formed from electrochromic glass and may cover photovoltaic cells and touch sensors. Driver boards may be mounted within a clutch barrel perpendicular to the display.

Claims:
What is claimed is: 
     
       1. A portable computer, comprising:
 upper and lower housings, wherein the upper housing has a front surface and a rear surface; 
 a hinge connecting the upper and lower housings; 
 a display mounted that forms a portion of the front surface of the upper housing, wherein the display has four edges; 
 a peripheral housing member that surrounds the four edges of the display; and 
 a rectangular plate that is mounted within the peripheral housing member, wherein the rectangular plate at least partially forms the rear surface of the upper housing. 
 
     
     
       2. The portable computer defined in  claim 1  wherein the peripheral housing member comprises metal. 
     
     
       3. The portable computer defined in claim  2  wherein the rectangular plate comprises a material selected from the group consisting of: metal, glass, ceramic, fiber composite, and plastic. 
     
     
       4. The portable computer defined in  claim 2  wherein the rectangular plate comprises glass. 
     
     
       5. The portable computer defined in  claim 1  wherein the peripheral housing member comprises fiber composite material. 
     
     
       6. The portable computer defined in  claim 5  wherein the peripheral housing member comprises an opening in which an antenna is formed. 
     
     
       7. The portable computer defined in  claim 1  wherein the peripheral housing member comprises an integral shelf structure, wherein the display comprises at least one planar member that is mounted to a first side of the integral shelf structure, and wherein the rectangular plate is mounted to a second side of the integral shelf structure. 
     
     
       8. The portable computer defined in  claim 7  further comprising:
 a clutch barrel that covers the hinge; and 
 a display driver board mounted within the clutch barrel. 
 
     
     
       9. The portable computer defined in  claim 1  wherein the peripheral housing member comprises an integral shelf structure, the portable computer further comprising at least one light-emitting diode mounted on the integral shelf structure. 
     
     
       10. The portable computer defined in  claim 1  further comprising a shelf structure that is attached to the peripheral housing member, wherein the rectangular plate is mounted to the peripheral housing member. 
     
     
       11. The portable computer defined in  claim 10  further comprising at least one light-emitting diode mounted on the shelf structure. 
     
     
       12. The portable computer defined in  claim 1  wherein the display comprises a touch screen having a touch sensor array. 
     
     
       13. The portable computer defined in claim  1  wherein the display has at least one curved corner. 
     
     
       14. The portable computer defined in  claim 13  wherein the peripheral housing member has at least one curved corner. 
     
     
       15. The portable computer defined in  claim 1  wherein the rectangular plate has at least one curved corner. 
     
     
       16. The portable computer defined in  claim 1  further comprising antenna traces on the rectangular plate. 
     
     
       17. The portable computer defined in  claim 1  further comprising a camera that receives light through the rectangular plate.

Description:
BACKGROUND 
     This relates to electronic devices such as computers, and more particularly, to displays and display-based features for computers. 
     Computers such as portable computers are often provided with liquid crystal displays. Portable computers typically have upper and lower housings that are connected by a hinge. The lower housing contains computer keys and a pointing device such as a track pad. The upper housing contains a display. The hinge allows the upper housing to be opened when the computer is in use and to be closed when it is desired to protect the keys and other components of the lower housing. 
     Typical housing materials for computers include plastic and metal. The display is generally a liquid crystal display (LCD). Components that are associated with the display such as a light reflector layer and backlight may be mounted inside the upper housing. The plastic or metal of the upper housing forms an enclosure that protects the rear surface of the display and the other components from damage. An opening in formed in the front of the upper housing to allow the user of the computer to view images on the display. 
     Conventional computers such as these are sometimes bulkier and less aesthetically appealing than desired and may lack desirable user interface features. For example, the housing of the computer may be thicker and less attractive than desired and may be devoid of capabilities that would make the computer more appealing to use. 
     It would therefore be desirable to provide improved computers such as computers with improved housing and display features. 
     SUMMARY 
     Electronic devices such as portable computers may be provided. The electronic devices may have housings such as upper and lower housings that are connected by hinges. The hinges may allow the upper housing to rotate relative to the lower housing. 
     The upper housing may contain a display on its front face. A rear plate may be formed on the rear face of the upper housing. The lower housing may have a front plate on its front surface and a rear plate on its rear surface. 
     A peripheral housing member may surround the display and rear plate in the upper housing. A peripheral housing member may surround the front and rear plates in the lower housing. The peripheral housing members may each be formed from a metal or other materials. An antenna may be formed in an opening in a peripheral housing member or may be mounted adjacent to a peripheral housing member. During operation, antenna signals may pass through dielectric layers associated with a liquid crystal display on the front of the upper housing and may pass in the opposite direction through the rear plate in the upper housing. The hinges that connect the upper and lower housings may include hinge structures that are integral to the peripheral housing member. 
     The front and rear plates may each be formed from a material such as glass, ceramic, metal, fiber composites, or plastic. When formed from a material such as glass, the rear plate may be transparent and may allow light to pass through the rear of the housing. The light may be used to illuminate a logo. A patterned masking layer on the rear plate may be used to define the shape of the illuminated logo. Light for illuminating the logo may be light that passes through a light reflector in a liquid crystal display backlight unit. 
     The backlight unit may have four edges. Light-emitting diodes for launching backlight into the light guide layer may be located along one or more of the edges. Insert molding techniques may be used to mold the light guide layer over the light-emitting diodes. A substrate for mounting the light emitting diodes such as a flex circuit substrate may be provided with openings. The light-emitting diodes may be mounted upside down within the openings to conserve space. 
     The rear plate may be formed from laminated layers including a light guide plate layer for a backlight unit. A two-sided display may be formed in which one display is front facing and the other display is rear facing. The displays may share a common light guide layer. 
     Display structures and the rear plate may be mounted to opposing sides of a shelf portion of the peripheral housing member. The rear plate may be formed from electrochromic glass. Photovoltaic cells may be located under the rear plate and may produce power when activated by an external light source. Touch sensors may be located under the rear plate and may gather touch input. A control unit may be used to process touch commands on the rear plate to perform functions such as unlocking a magnetic latch that holds the upper housing to the lower housing. 
     The display may be controlled using timing and control circuitry on a display driver board. The driver board may be mounted within a clutch barrel that contains the hinges. The driver board may be mounted within the clutch barrel so that it lies perpendicular to the plane of the display or may be oriented at other orientations such as orientations that are within plus or minus 10° or 20° from perpendicular, orientations that are parallel to the plane of the display, or other orientations. 
     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. 1A  is a front perspective view of an illustrative electronic device such as a portable computer in accordance with an embodiment of the present invention. 
         FIG. 1B  is a rear perspective view of an illustrative electronic device such as the device of  FIG. 1A  in accordance with an embodiment of the present invention. 
         FIG. 2  is a schematic diagram of an illustrative electronic device such as the device of  FIGS. 1A and 1B  in accordance with an embodiment of the present invention. 
         FIG. 3  is a perspective view an illustrative display module of the type that may be used to form the upper housing of a portable computer of the type shown in  FIGS. 1A and 1B  in accordance with an embodiment of the present invention. 
         FIG. 4  is a cross-sectional side view of an edge portion of the display module of  FIG. 3  showing how the display module may have a six-sided box configuration in accordance with an embodiment of the present invention. 
         FIG. 5  is an exploded perspective view of a display module in accordance with an embodiment of the present invention. 
         FIG. 6  is a cross-sectional side view of an edge portion of a display module of the type shown in  FIG. 3  showing how display components such as a backlight layer may be interposed between a rear housing layer and display layers in accordance with an embodiment of the present invention. 
         FIG. 7  is a perspective view of an illustrative frame that may be used in forming a display module in accordance with an embodiment of the present invention. 
         FIG. 8A  is a cross-sectional side view of a display module frame before insertion of front and rear rectangular plate structures in accordance with an embodiment of the present invention. 
         FIG. 8B  is a cross-sectional side view of the display module of  FIG. 8A  following insertion of a front or rear plate structure in accordance with an embodiment of the present invention. 
         FIG. 8C  is a cross-sectional side view of the display module of  FIG. 8B  following attachment of both front and rear plate structures in accordance with an embodiment of the present invention. 
         FIG. 9  is a cross-sectional diagram of an edge portion of an illustrative display module showing how light emitting diodes for providing backlight to a display may be mounted on a shelf in the display module frame in accordance with an embodiment of the present invention. 
         FIG. 10  is a top view of a portion of an illustrative display module frame showing how an opening may be formed in the frame to accommodate an antenna in accordance with an embodiment of the present invention. 
         FIG. 11A  is a top view of a display module frame showing illustrative antenna locations in accordance with an embodiment of the present invention. 
         FIG. 11B  is a cross-sectional side view of an illustrative display module showing how radio-frequency antenna signals may pass through portions of front and rear housing plates when an antenna is formed in part of a peripheral housing frame member and when an antenna is formed adjacent to a peripheral housing frame member in accordance with embodiments of the present invention. 
         FIG. 12  is a perspective view of an illustrative discrete clutch mechanism of the type that may be used in a hinge for the portable computer of  FIGS. 1A and 1B  in accordance with an embodiment of the present invention. 
         FIG. 13  is a perspective view of an illustrative integrated clutch mechanism of the type that may be used in a hinge for the portable computer of  FIGS. 1A and 1B  in accordance with an embodiment of the present invention. 
         FIG. 14  is a cross-sectional side view of an edge portion of a display module showing how the display module may use laminated layers in forming the rear plate structure in accordance with an embodiment of the present invention. 
         FIG. 15  is a perspective view of an illustrative display module having an illuminated logo in a rear plate structure in accordance with an embodiment of the present invention. 
         FIG. 16  is a cross-sectional side view of the display module of  FIG. 15  taken through the logo of  FIG. 15  in accordance with an embodiment of the present invention. 
         FIG. 17  is a cross-sectional side view of a display module showing how antenna traces may be formed on the underside of the rear plate structure in accordance with an embodiment of the present invention. 
         FIG. 18  is a cross-sectional side view of an illustrative display module having an integrated touch sensor formed under a rear plate structure in accordance with an embodiment of the present invention. 
         FIG. 19  is a cross-sectional side view of an illustrative display module having front and rear plate structures in which the rear plate structure includes a light guide layer in accordance with an embodiment of the present invention. 
         FIG. 20  is a cross-sectional end view of an illustrative clutch barrel structure in which a display driver board is mounted in accordance with an embodiment of the present invention. 
         FIG. 21  is a cross-sectional side view of a portion of a display module showing how light source components such as light-emitting diodes may be mounted on a driver board substrate that is interposed between front-side display structures such as liquid crystal display structures and a rear plate structure in accordance with an embodiment of the present invention. 
         FIG. 22  is a side view of an illustrative display module having an electrochromic glass structure, a front display structure, a rear display structure, and a shared backlight in accordance with an embodiment of the present invention. 
         FIG. 23  is a side view of an illustrative display module having an electrochromic glass layer, a reflector, a backlight, and a front-side liquid crystal display structure in accordance with an embodiment of the present invention. 
         FIG. 24  is a cross-sectional side view of an illustrative display module with photovoltaic cell structures that receive light through a rear plate in accordance with an embodiment of the present invention. 
         FIG. 25  is a top view of an illustrative light-emitting diode layout that may include opposing rows of light-emitting diodes for illuminating a display such as a liquid crystal display in accordance with an embodiment of the present invention. 
         FIG. 26  is a cross-sectional side view of a conventional configuration for mounting light-emitting diodes on a printed circuit board substrate. 
         FIG. 27  is a cross-sectional side view of an illustrative configuration for mounting light-emitting diodes to a printed circuit board substrate in accordance with an embodiment of the present invention. 
         FIG. 28  is a top view of an illustrative set of light-emitting diodes mounted to a printed circuit board substrate using an upside down orientation of the type shown in  FIG. 27  in accordance with an embodiment of the present invention. 
         FIG. 29  is a side view of an illustrative substrate on which a light-emitting diode or other light source for illuminating a display has been mounted in accordance with an embodiment of the present invention. 
         FIG. 30  is a cross-sectional side view of a substrate of the type shown in  FIG. 29  that has been placed into an insert-molding tool cavity in accordance with an embodiment of the present invention. 
         FIG. 31  is a cross-sectional side view of an illustrative substrate of the type shown in  FIG. 29  following the insert molding of an encompassing layer of light-guide panel material over the light-emitting diode in accordance with an embodiment of the present invention. 
         FIG. 32  is an exploded perspective view of a portion of an electronic device having rounded display and housing corners in accordance with an embodiment of the present invention. 
         FIG. 33  is a cross-sectional side view of a portion of a housing for an electronic device showing how display structures may be surrounded by a trim member and showing how the display frame may be thinner than the overall thickness of the device housing and mounted components in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     This relates to electronic devices such as electronic devices with displays. The electronic devices may be tablet computers, cellular telephones and other handheld electronic devices, portable computers, other portable electronic devices, computer monitors, computer monitors with embedded computers, televisions, and other electronic equipment. In a typical configuration, the electronic device is a portable computer, so examples that are based on portable computers are sometimes described herein as examples. This is, however, merely illustrative. Any suitable electronic device may be provided with a display and other structures of the types described herein if desired. 
     An illustrative electronic device (e.g., a portable computer) is shown in  FIG. 1A . As shown in  FIG. 1A , electronic device  10  may have a housing such as housing  12 . Housing  12  may be formed from materials such as metal (e.g., aluminum), ceramic, glass, plastic, carbon fiber and other fiber composites, other materials, and combinations of these materials. 
     Housing  12  may include upper housing portion  12 A and lower housing portion  12 B. Housing portions  12 A and  12 B may be connected using hinge structures in region  20  (sometimes referred to as a clutch barrel or clutch barrel structures). The hinges in clutch barrel  20  may allow upper housing  12 A to rotate relative to lower housing  12 B about rotational axis  22  in directions  24 . Camera  13  may be formed along one of the edges of upper housing  12 A (as an example). 
     Lower housing  12 B, which may sometimes be referred to as a base or base unit, may include components such as keyboard  16  and pointing device  14 . Pointing device  14  may be a track pad and may have associated buttons. Input-output ports may be provided in the housing for main unit  12 B. The interior of main unit  12 B may include components such as a main logic board, peripheral cards, a battery, communications circuits and busses, wireless transceiver circuitry, etc. 
     Upper housing  12 A, which may sometimes be referred to as a display housing, may include display  18 . Upper housing  12 A may also include other electrical components. These components may be mounted within clutch barrel  20 , behind display  18 , or in the peripheral region surrounding the outer periphery of display  18 . 
     A rear perspective view of electronic device  10  of  FIG. 1A  is shown in  FIG. 1B . As shown in  FIG. 1B , device  10  may include outer (exterior) planar surfaces such as surfaces  26  and  28 . Planar surface  26 , which may sometimes be referred to as a rear surface, is on the opposite (opposing) side of housing  12 A from display  18  (i.e., display  18  is typically referred to as being on the front side of display housing  12 A, whereas surface  26  is typically referred to as being on the back side or rear of display housing  12 A). Similarly, surface  28  may sometimes be referred to as forming a rear surface for base unit housing  12 B. When the lid (structure  12 A) of device  10  is open, the front and rear surfaces of structure  12 A are both exposed. 
     In general, surfaces such as surfaces  26  and  28  may be formed from materials such as plastic, ceramic, glass, metal, composites, other materials, and combinations of these materials. With one suitable arrangement, which is sometimes described herein as an example, planar surface  26  (and optionally planar surface  28  and front surface  29  of  FIG. 1A ) may be formed from a rectangular plate of dielectric material such as glass, ceramic, or composite materials. The housing structures that form front surface  29 , rear surface  26 , and rear surface  28  are therefore sometimes referred to as being implemented using glass plates, glass-like planar structures, planar members, glass layers, housing plates, etc. Plate  26  (and the other plates used in device  10 ) may be less than 5 mm thick, less than 3 mm thick, less than 2 mm thick, less than 1 mm thick, 0.3 to 1.3 mm thick, about 0.8 mm thick, etc. 
     If desired, housing plate  26  may include a logo such as logo  30 . Logo  30  may be formed from a different material than the rest of plate  26  or may be formed by patterning an interior layer of opaque ink in a way that allows a logo-shaped pattern of light to be emitted through plate  26 . The light for illuminating logo  30  may be light that escapes from a liquid crystal display backlight through a reflector layer (e.g., a reflector layer formed from a sheet of translucent material such as white polyester). 
     A schematic diagram of electronic device  10  of  FIGS. 1A and 1B  is shown in  FIG. 2 . As shown in  FIG. 2 , device  10  may include a power source such as battery  34 . Power circuits  32  may be used to deliver power from battery  34  or an alternating current (AC) line source to circuitry in device  10 . 
     Control circuitry  36  may include microprocessors, digital signal processors, microcontrollers, and control circuitry in application-specific integrated circuits. Control circuitry  36  may also include memory circuitry such as hard drive devices, solid state storage, volatile and non-volatile memory chips, memory circuits that are part of processors and other integrated circuits, and other storage devices. During operation of device  10 , control circuitry  36  may be used to supply control signals to adjustable components in device  10 . Control circuitry  36  may also be used to transmit and receive data from external equipment. 
     Input-output devices  38  may be used to assist control circuitry  36  in interfacing with a user of device  10  and external equipment. For example, input-output devices  38  may include user input interfaces such as mice, trackballs, track pads, buttons, touch sensors, touch screen displays, cameras, microphones, speakers, etc. Input-output devices  38  may also include data ports, audio ports, and other input-output ports. Wireless circuitry in devices  38  and associated antennas (e.g., radio-frequency transceiver circuitry) may be used in transmitting and receiving radio-frequency antenna signals (e.g., cellular telephone signals, wireless local area network signals, etc.). Among other components, input-output devices  38  may include a display such as display  18  (see, e.g.,  FIG. 1A ) and touch sensors  40 . 
     Display  18  may be a plasma display, an organic light-emitting diode (OLED) display, a liquid crystal display (LCD), or other suitable display. Display  18  may be rectangular and may have four peripheral edges (e.g., right, left, top, and bottom edges that run around the outer periphery of display  18 ). Touch sensors  40  may be implemented using capacitive touch sensors, acoustic touch sensors, piezoelectric touch sensors or other force-sensing components, optical touch sensors, resistive touch sensors, or other touch sensitive components. Touch sensors  40  may be implemented in an array of rows and columns (as an example). In a typical scenario, touch sensors  40  may be implemented as an array of capacitive sensor electrodes formed from a conductor such as indium tin oxide and may be integrated into one of the layers of display  18  to form a touch screen display. Other types of configurations may be used if desired (e.g., to implement touch sensitive buttons, to implement one-dimensional sliders based on touch technology, etc.). Touch sensors may, if desired, be placed under rear plate  26 , so that touch input can be gathered from the rear surface of housing  12 A. 
     The structures such as the housing structures in display housing  12 A that surround and encase the internal components of display  18  are sometimes said to form a module. Display housing  12 A and the display structures that are used in forming display housing  12 A are therefore sometimes referred to as forming a display module. 
     A perspective view of an illustrative display module (module  12 A) is shown in  FIG. 3 . As shown in  FIG. 3 , display module  12 A may include a central planar display region for display  18  surrounded by peripheral housing structures. Display  18  may, for example, be surrounded by a peripheral housing member such as band-shaped peripheral member  56  of the type that is sometimes referred to as a frame. Peripheral housing member  56  may run along each of the four edges of display  18 , thereby surrounding display  18 . An optional rectangular bezel such as bezel  42  may be used to provide a cosmetic trim around the four edges of display  18  if desired. Hinges such as hinges  58  may be associated with clutch barrel  20 . Each hinge may include holes such as holes  60  through which screws may pass to screw hinges  58  to lower housing  12 B. Hinges  58  of  FIG. 3  may be attached to mating hinge structures in the hidden portion of clutch barrel  20  of  FIG. 3 . Hinge friction may be used to allow a user to place display housing  12 A at a desired orientation with respect to base housing  12 B. 
     A cable such as a coaxial cable or flex circuit cable  62  may be used to route electrical signals to and from display  18  and other components in display module  12 A. When display module  12 A is mounted to lower housing  12 B, the end of cable  62  may be plugged into a mating connector (e.g., a connector associated with another cable or a printed circuit board). Cable  62  may be used to carry image data that is to be displayed on display  18 . Cable  62  or other cables may also be used to carry antenna signals, control signals, data signals, and other signals that are to be conveyed between housings  12 A and  12 B. Cable  62  may be located at a corner of the display, at a point that is midway along one of the edges of the display, at other locations, etc. 
     Display module  12 A may have four edges such as upper and lower edges  50  and left and right edges  54 . A cross-sectional view of a display module edge (e.g., a cross-sectional view of an edge of a display module such as a view of edge  50  of  FIG. 3  taken along line  44  and viewed in directions  46  or of edge  54  of  FIG. 3  taken along line  48  and viewed in directions  52 ) is shown in  FIG. 4 . As shown in the example of  FIG. 4 , display module  12 A may have a rear planar member such rear plate  26 . Rear plate  26  may be formed from one or more layers of material such as one or more layers of glass, ceramic, metal, plastic, composites, conductive materials, dielectrics, etc. For example, rear plate  26  may include at least an exterior portion that is formed from a layer of glass. 
     Peripheral housing member  56  may have a T-shaped cross-section, as shown in  FIG. 4 . The stem of the T may form shelf structure  64 . The top of the T may form a peripheral outer housing wall including outer peripheral surface  74 , rear surface  76 , and front surface  78 . Front surface  78  may, if desired, be covered with a cosmetic bezel (see, e.g., bezel  42  of  FIG. 3 ). Peripheral housing member  56  may be formed from metal (e.g., aluminum, stainless steel, titanium, etc.), composites (e.g., carbon fiber), or other suitable materials. 
     Shelf structure  64  may have a rear surface such as surface  66  and a front surface such as front surface  67 . Rear planar member  26  may be supported by rear shelf surface  66 . Display structures  72  may be supported on front shelf surface  67 . Elastomeric gaskets  68  and  70  may be used to help prevent damage to the edges of plate  26  and display structures  72 . In this configuration, peripheral housing member  56  may surround the four edges of rectangular display structures  72  and the four edges of rectangular rear plate  26 . 
     Display structures  72  may include an outermost planar member such as a layer of coverglass (i.e., a plastic or glass covering plate on the front of display module  12 A) and inner layers such as a color filter layer, a thin-film transistor layer, an optional touch sensor array, polarizers and other optical films, etc. If desired, the layer of coverglass may be omitted from display  18  and the outermost layer of display structures  72  (e.g., a polarizer, a color filter layer, or other such layer) may serve as the outermost layer of display  18 . Because structures  72  typically include at least one outer planar layer, structures  72  are sometimes referred to as forming a front plate or front-side planar structures. Internal structures  74  may be interposed between rear plate  26  and front plate  72 . Internal structures  74  may include components such as display components (e.g., backlight structures, polarizers and other optical films, a light reflector, etc. 
     The structures of display module  12 A of  FIG. 4  form a type of six-sided box. Four of the sides of the box are formed by the upper, lower, left, and right edges of peripheral housing member  56 . The other two sides of the box may be formed by rear plate  26  and front plate  72 , respectively. A box construction of this type may be strong and stiff, allowing the thickness of layers  72 ,  74 , and  26  to be minimized without compromising the structural integrity of display module  12 A. This box construction may also facilitate greater freedom of assembly and rework over display module constructions that permit assembly from only one direction. Display module  12 A permits assembly from two opposing directions (front and rear). During manufacturing operations, front plate  72  may be attached to housing member  56  before rear plate  26  or rear plate  26  may be attached to housing member  56  before front plate  72 . If a repair is needed, one of the plates can be removed and the interior of display module  12 A can be accessed from the side of module  12 A that has been opened. 
     An exploded perspective view of an illustrative display module is shown in  FIG. 5 . As shown in  FIG. 5 , display module  12 A may include rear plate  26 . The inner surface of rear plate  26  may be coated with an opaque layer such as ink layer  80 . Ink layer  80  may be patterned. For example, an opening such as opening  82  may be formed in ink layer  80 . Opening  82  may have the shape of a logo and may be used in forming logo  30  of  FIG. 1B . 
     Ink layer  80  may have any suitable color or colors such as blue, green, red, magenta, grey, etc. Multiple colors of ink may be formed on a single plate. For example, a pattern of strips, dots, or other designs may be formed using inks of different colors and shades. Screen printing, shadow masking, pad printing, ink-jet printing, spraying, and other fabrication techniques may be used informing patters of ink in layer  80 . If desired, the ink pattern for layer  80  may be customized. For example, a user may select from a predetermined list of patterns or may upload a photograph or other image to be used as a template for forming the ink pattern. Custom ink layers  80  that are formed in this way may have one color, two colors, three colors, four colors, or more than four colors. The resolution of the ink layer pattern may be limited (e.g., to facilitate high manufacturing throughput) or may be near photographic in quality (e.g., 30-300 dots per inch). Combinations of predetermined ink patterns (e.g., standard border templates) and custom patterns (e.g., customized regions of ink layer  80 ) may be formed if desired. 
     Structures  102  may form a backlight unit for display  18 . Structures  102  may include a light reflector such as reflector  84 . Reflector  84  may be formed from a translucent layer of material such as white polyester. Reflector  84  may reflect diffuse light towards display structures  72 . Some light may pass through reflector  84  and may escape through opening  82  in plate  26  to serve as illumination for logo  30 . Structures  102  may include a light guide (sometimes referred to as a light guide plate). Light guide plate  86  be about 0.55 mm to 0.7 mm thick and may be formed from a layer of clear plastic such as polymethylmethacrylate (as an example). Light-emitting diodes on light-emitting diode flex circuit  92  may launch light into one or more edges of light guide plate  86 . This light may be spread over the surface area of display structures  72  by total internal reflection within plate  86 . Some of the light escapes plate  86  in the direction of display structures  72  and serves as backlight for display  18 . When the light escapes plate  86  in the direction of reflector  84 , reflector  84  will reflect most of the escaped light back through the light guide plate and towards display structures  72 . 
     Light guide plate  86  may be coated with one or more optical films  88  (e.g., birefringent films, polarizing films, and other films that form part of a liquid crystal display or other suitable display). 
     Adhesive ring  90  may be formed from a pressure sensitive adhesive and may be used to attach rear plate  26  to peripheral housing member  56  (e.g., by bonding the plate to shelf surface  66 ). 
     Hinges  58  may be screwed to lower housing  12 B ( FIG. 1A ) and may each have a shaft or other structure that mates with a portion of a respective one of mating hinge structures  104 . Mating hinge structures  104  on member  56  may be formed as an integral portion of member  56  or may be a separate structure that is attached to member  56 . 
     A light-blocking seal structure such as shelf foam  94  may be used in preventing light leakage in the display. A timing controller integrated circuit (sometimes referred to as an LCD driver chip) for display  18  may be mounted on substrate  100  (sometimes referred to as an LCD driver board). The timing controller integrated circuit may serve as an interface between the graphics circuitry (integrated or discrete) in device  10  and the row and column drivers in the pixel array of display  18 . 
     Clutch barrel cover  20  may cover LCD driver board  100 , hinge structures  104 , and other structures mounted along the lower edge of member  56 . Display structures  72  may include an optional cover layer (e.g., a cover glass layer), a color filter layer (which may serve as a cover glass layer in the absence of a separate cover glass layer), a thin-film transistor layer (i.e., a layer that contains an array of thin-film transistor drivers that create electric fields for controlling associated liquid crystal material that is interposed between the color filter layer and thin-film transistor layer), an optional touch sensor array layer, a polarizer layer or layers, birefringent films, other optical films, etc. 
     As shown in  FIG. 6 , display structures  72  (i.e., the front plate of display module  12 A) may be attached to surface  67  of shelf structure  64  using adhesive  98  and rear plate  26  may be attached to surface  66  of shelf structure  64  using adhesive  90 . The components of backlight unit  102  may be mounted inside frame  56  and, once assembled, may be captured between liquid crystal display structures  72  and rear plate  26 . As shown in  FIG. 6 , the resulting assembly may form a solid stack that is interrupted only by minimal air gap  110  (e.g., an air gap in the range of 0.05 to 2 mm) between back light unit  102  and lower polarizer layer  106  on display structures  72  to prevent wetting in optical films  88 . Some or all of the layers of material in backlight unit  102  may be attached to each other using adhesive or some or all of the layers of material in backlight unit  102  may be unattached (floating). Floating arrangements may help prevent damage to backlight unit  102  as device  10  is flexed during use. 
     The configuration of  FIG. 6  allows the lateral (X and Y) dimensions of display structures  72  (and therefore display  18 ) to be maximized. Gasket  68  (sometimes referred to as a trim bead) may be interposed between portion  56 ′ of member  56  and the outermost edge of display structures  72 . Protruding portion  112  of gasket  68  may help maintain a gap between the exposed surface of display structures  72  and main unit (top case)  12 B when upper portion (lid)  12 A is in a closed position. As described in connection with  FIG. 4 , arrangements of the type shown in  FIG. 6  form a six-sided box construction that may enhance the rigidity of the assembly and thereby help prevent undesired bending or twisting of display module  12 A. 
       FIG. 7  is a perspective view showing an illustrative arrangement that may be used for peripheral housing member  56 . As shown in  FIG. 7 , housing member  56  may have integral hinge structures  104 , each of which mates with a corresponding one of hinges  58  of  FIG. 5 . An opening such as rectangular hole  114  may be used to accommodate a flexible printed circuit (“flex circuit”) cable for connecting LED flex circuitry to driver board  100 , or for connecting circuitry in display housing  12 A to circuitry in base housing  12 B. 
       FIGS. 8A ,  8 B, and  8 C are simplified cross-sectional side views of display module  12 A showing how display module  12 A may be assembled. Initially, peripheral housing member  56  may appear as shown in  FIG. 8A . In this configuration, no additional components have been attached to housing member  56 . 
     Additional components such as a front plate or rear plate and interior components may then be attached to housing member  56 . In the  FIG. 8B  example, display structures  72  have been attached to shelf  64  and interior components  74  have been mounted within the interior of housing member  56 . 
     As shown in  FIG. 8C , assembly may be completed by adding the remaining plate structure (i.e., rear plate  26  in the  FIG. 8C  example). Screws and other fasteners, adhesives, and other attachment mechanisms may be used when mounting components within housing  12 A. Because components can be mounted to both the front and rear sides of housing member  56 , assembly and rework operations are generally more flexible than arrangements such as conventional “bucket” display enclosure arrangements in which components can be mounted in only a single direction. 
       FIG. 9  is a cross-sectional side view of a portion of display module  12 A along its lower (clutch barrel) edge. As shown in  FIG. 9 , shelf portion  64  of housing member  56  may serve as a support for light sources such as light-emitting diodes  92 L. Diodes  92 L may be mounted on flex circuit  92  and may emit light  116  into light guide plate  86 . Reflector  84  may ensure that most of light  116  is scattered in direction  118  through display structures  72 . Foam strip  94  may be interposed between light guide plate  86  and shelf portion  64  of housing member  56  and may form a light-tight seal that blocks stray rays of light  116  from the array of diodes  92 L on flex circuit  92  and thereby ensures that the image quality of display structures  72  is not adversely affected by light leakage. 
     Driver board  100  may include a timing controller integrated circuit (IC) for the thin-film transistors and other display circuitry of display  18 . The timing controller integrated circuit may be mounted on any suitable substrate. For example, driver board  100  may be based on a substrate such as a rigid printed circuit board substrate such as FR-4, a flexible polymer sheet such as a polyimide flex circuit substrate, a ceramic plate, other dielectric substrate materials, etc. To improve mounting efficiency, driver board  100  may be arranged so that the plane of driver board  100  lies parallel to the “Z” axis of display module  12 A (i.e., so that driver board  100  is perpendicular to display  18  and lateral axis “Y,” which runs parallel to the left and right edges of display module  12 A). Driver board  100  may also be mounted at other orientations with respect to display  18  (e.g., parallel to display  18 , within plus or minus 10° or 20° of a plane that is perpendicular to the plane of display  18 , etc.). 
     Antennas may be located within housing member  56 . For example, recesses may be formed within member  56  that accommodate antenna structures. The recess may, for example, be formed by milling, casting, or otherwise removing part of the conductive material in a conductive (e.g., metal) housing member such as member  56 . A recess of this type may form a conductive cavity. The conductive cavity may be used in forming a cavity backed antenna. Printed circuit boards and other substrates that contain metal traces may be placed within a conductive cavity in member  56 . 
     If desired, openings may be formed in housing member  56  that pass completely through housing  56 . An opening may, for example extend from the front surface to the rear surface of housing member  56  (running along dimension Z), as shown by opening  120  in  FIG. 10 . Within this opening, printed circuit boards with traces, metal structures formed from parts of a housing, wire, metal foil, metal members, or other conductive structures may be formed. These conductive structures may form some or all of an antenna (see, e.g., antenna structure  122  of  FIG. 10 , which is separated from the inner walls of opening  120  in housing member  56  by dielectric insulating member  124 ). Slot antennas may be formed in housing member  56  by forming openings of the type shown in  FIG. 10 . These openings may form closed slots that are completely surrounded by metal or other conductive material in housing member  56  or open slots that have a closed end and an open end). 
       FIG. 11A  shows how multiple antenna openings may be formed through housing member  56  (e.g., openings  120 A,  120 B,  120 C,  120 D,  120 E, and  120 F). 
       FIG. 11B  is a cross-sectional side view of an illustrative display module showing how radio-frequency antenna signals  127  may pass through portions of front plate  72  and rear plate  26  in display module  12 A when an antenna is formed in opening  120  in a portion of housing member  56  such as shelf portion  64 .  FIG. 11B  also shows how radio-frequency antenna signals  121  may pass through portions of front plate  72  and rear plate  26  when an antenna such as antenna  123  is formed from a structure that is mounted at a suitable location within the interior of display module  30  (e.g., adjacent to shelf  64 ). In configurations in which radio-frequency signals can propagate through both the front and rear surfaces of display module  12 A, potential reductions in antenna efficiency upon closure of the lid of device  10  can be minimized. 
     Antennas such as antennas in openings  120  and antenna  123  of  FIG. 11B  may cover communications bands such as cellular telephone bands, satellite navigation bands, wireless local area network bands, or other communications bands of interest. 
     A perspective view of an illustrative configuration that may be used for hinge  58  and mating hinge structure  104  is shown in  FIG. 12 . As shown in  FIG. 12 , hinge  58 , which may sometimes be referred to as a clutch band, may have a cylindrical opening that receives shaft  104 A of mating hinge structure  104 . Hinge structure  104 , which may sometimes be referred to as a clutch pillar, may have a base portion  104 B that is separate from housing member  56 . Adhesive, welds, screws, and other attachment mechanisms may be used in attaching hinge structure  104  to housing member  56 . As shown in  FIG. 12 , for example, hinge structure  104 B may have screw holes  126  that may receive screws to screw structure  104 B to housing member  56 . If desired, hinge structure (clutch pillar)  104  may be formed from metal or other material that is an integral portion of housing member  56  (see, e.g., the illustrative integral hinge structure arrangement of  FIG. 13  in which surface  128  of hinge structure base  104 B is devoid of screw holes). 
     Rear plate  26  of display module  12 A may contain multiple layers of material. These layers may be attached to one another using adhesive or other suitable lamination techniques (e.g., by bonding layers to each other through the application of heat and pressure). The layers of rear plate  26  may include metal layers, plastic layers, glass layers, ceramic layers, layers of carbon fiber and other composites, other materials, and layers that include combinations of these materials. A metal layer or other durable layer may be bonded to a layer of a material such as glass or ceramic to contain shards of broken glass or ceramic material in the event that rear plate  26  is damaged. Coatings may also be applied to rear plate  26  to enhance environmental resistance, etc. (e.g., an oleophobic coating can be applied to resist oily fingerprints). In the example of  FIG. 14 , rear plate  26  has an outer layer  130  (e.g., glass, etc.) and an inner layer  132  (e.g., metal). Other laminated stacks may be formed if desired (e.g., stacks in which layer  130  is formed from one type of glass and layer  132  is formed from another type of glass, etc.). 
       FIG. 15  is a perspective view of display module  12 A showing how logo  30  may be formed in the middle of plate  26 . A cross-sectional side view of display module  12 A of  FIG. 15  taken along line  134  and viewed in direction  136  is shown in  FIG. 16 . As shown in  FIG. 16 , display module  12 A may have a light source that emits light  116  into light guide plate  86 . Light  116  is scattered through the front of display module  12 A (e.g., through liquid crystal display structures  72 ) as rays  136  and serves as backlight for display  18 . Reflector  84  (e.g., a sheet of white polyester or other suitable translucent material) helps reflect light  116  in the direction of rays  136 . However, some of light  116  escapes to the rear of display module  12 A as light rays  142 . 
     Rear plate  26  may be formed from a transparent substance such as clear glass, tinted glass, clear or tinted plastic, etc. Opaque masking layer  138  (e.g., a layer such as layer  80  of  FIG. 5 ) may be formed as a patterned coating on the inner surface of rear plate  26 . For example, ink layer  138  may be a layer of black ink that is coated over the entirety of rear plate  26  with the exception of logo-shaped opening  140  (e.g., an opening having the shape of logo  30  of  FIG. 15  and opening  82  of  FIG. 5 ). Light  142  can be blocked by ink layer  138 , but can escape through opening  140  (e.g., as white light) and can pass through rear plate  26  to serve as internal illumination for logo  30 . Ink layer  138  may have one or more colors (e.g., black, grey, blue, green, red, shades of these colors, etc.) and may be solid or patterned. 
     Masking layer  138  may be formed from a material that is radio transparent. This allows radio-frequency signals such as antenna signals to pass through layer  138  when plate  26  overlaps antennas formed in housing member  56  (e.g., when plate  26  and masking layer  138  cover antennas such as the antennas in openings  120  of  FIGS. 10 and 11B , antennas in locations  120 A,  120 B,  120 C,  120 D,  120 E, and  120 F of  FIG. 11A , and antennas such as antenna  123  of  FIG. 11B ). 
     As shown in  FIG. 17 , an antenna such as antenna  152  may be formed under masking layer  138 . Antenna  152  may be formed from conductive traces  154 , metal wires, portions of housing member  56 , or other antenna structures. Radio-frequency transceiver  146  may be mounted on a substrate such as printed circuit board  144 . A transmission line such as a flex circuit cable or coaxial cable  148  may be used to couple transceiver  146  to antenna  152 . Cable  148  may be coupled to antenna feed terminals  146  and  148 . During operation, radio-frequency antenna signals  164  may be transmitted and received through masking layer  138  and rear plate  26  (and through the foam of display housing  12 A). Rear plate  26  may be formed from a low-loss dielectric such as glass, ceramic, plastic, radio-transparent composites such as fiberglass composites, or other materials that do not significantly attenuate antenna signals. 
     If desired, display module  12 A may include a camera such as camera  156 . Camera  156  may have a lens such as lens  160  that is aligned with a corresponding opening such as opening  158  in masking layer  138 . Opening  158  may allow light from an image such as light  162  to be received by lens  160 . Cameras such as camera  156  may also be mounted in a front-facing configuration within housing  12 A (see, e.g., camera  13  of  FIG. 1A ). 
     Rear plate  26  or display structures  72  may be provided with touch sensors (see, e.g., touch sensor  40  of  FIG. 2 ). A touch sensor array having one or more touch sensor electrodes  166  may be formed under masking layer  138 , as shown in  FIG. 18 . Touch sensor processor  168  may be used to convert capacitance data or other touch data from sensors (electrodes)  166  to position and motion information. The touch sensor array may be actuated by contact on (or in the immediate vicinity of) surface  172 . Using processor  168 , the touch sensor array may, for example, gather information on the location of a user&#39;s finger or other external object such as object  170  on or in the vicinity of surface  172  of rear plate  26  as the finger is used to input touch gestures. Touch signals from processor  168  may be provided to a microprocessor or other processing circuitry in control circuitry  36  ( FIG. 2 ) for processing. In response, control circuitry  36  may take appropriate actions in device  10 . In general, any display within device  10  (e.g., front-facing display  18  of  FIG. 1A , rear facing displays, etc.) may be provided with touch sensors such as touch sensor  40  of  FIG. 2  to implement a touch screen display. 
     For example, touch signals from a touch sensor under plate  26  may be used to lock or unlock lid  12 A (e.g., using a magnetic catch or other latching structure), may be used to gather a password or other code, may be used to control audio playback or other media playback operations in device  10 , or may be used for controlling other device functions. A touch sensor under rear plate  26  may, for example, be located under logo  130  (e.g., to implement an on-off switch for device  10  or a switch that toggles device  10  between a sleep state and an awake state). A touch sensor array of this type may be used to detect touch gestures such as swipe gestures. When a swipe is detected using electrodes  166  and circuit  168 , an appropriate action may be taken (e.g., device  10  may be awoken from a sleep state, may be locked or unlocked, may open or close a mechanical or magnetic latch, may change a volume in a media playback application, etc.). Magnetic latches may be implemented using permanent magnets, magnetic materials (e.g., magnetic stainless steel such as 410 or 430 stainless in all or part of housing member  56  or a separate structure), electromagnets, and other suitable arrangements. 
       FIG. 19  shows how light guide plate  86  may be laminated to reflector  84  and rear plate layer  174  to form rear plate  26 . Rear plate layer  174  may be formed from glass, glass coated with a pattered opaque inner masking layer, ceramic, metal, composites, plastic, or other materials. Reflector  84  may be formed from white plastic, white polyester, or other reflective materials that create diffuse reflected light. Light guide plate  86  may be formed from plastic, glass, or other materials into which light  116  is launched from a light source such as light-emitting diodes. Light that is reflected from reflector  84  and that is scattered from within light guide  86  serves as backlight  136  that passes through internal display structures  74  and display structures  72 . Layers such as layers  86 ,  84 , and  174  may be laminated using layers of adhesive, application of heat and pressure, or other lamination techniques. 
       FIG. 20  shows how display timing and control chip  180  may be mounted on driver board  100  (e.g., a printed circuit board) within clutch barrel  20 . Clutch barrel  20  may be formed from metal, plastic, or other materials and may be used to enclose hinges  58 , mating hinge structures  104 , driver board  100 , and other components. A screw such as screw  178  may be used to mount driver board  100  to housing member  56 . A bus such as a bus formed from a flex circuit such as flex circuit  176  may be used to route signals between circuit  180  and thin-film transistors on thin-film transistor layer  186  or other image pixel array in display structures  72 . Flex circuit  176  may be routed between board  100  and layer  186  through an opening in housing member  56  such as opening  184 . Flex circuit  176  may be attached to thin-film transistor layer  186  at attachment location  188  and to traces on board  100  at location  190  using conductive adhesive, solder joints, connectors, or other conductive attachment mechanisms. 
     Light-emitting diodes such as diode  92 L may be used to launch light into light guide  86  that provides backlight for display structures  72 . A cosmetic trim or gasket structure such as structure  182  (e.g., bezel  42  of  FIG. 3 ) may surround the edge of display  18  ( FIG. 1A ). Trim  182  may be formed from metal, glass, plastic, fiber composite material, etc. 
       FIG. 21  is a cross-sectional side view of display module  12 A showing how display timing controller integrated circuit  180  may be mounted on a substrate such as substrate  194  that is separate from housing member  56 . Substrate  194  may be a ceramic substrate, a printed circuit board substrate such as a rigid printed circuit board substrate, a substrate formed from another dielectric layer, etc. Substrate  194  may form a housing shelf that is secured to housing member  56  using adhesive or a fastening mechanism such as screw  192 . Light-emitting diodes such as diode  92 L may be mounted on substrate  194  and may be used to launch backlight  116  into light guide  86  along one or more edges of display  18 . Timing and control chip  180  and other driver board circuitry may also be attached to substrate  194 . 
     Electrochromic glass may be used to form rear plate  26 , as shown in the cross-sectional view of display module  12 A of  FIG. 22 . Electrochromic glass, which is sometimes referred to as electrically switchable glass, may receive control signals (e.g., voltage control signals) from control circuitry  36  ( FIG. 2 ). The control signals can be used to place electrochromic glass  26  in either a transparent (light-passing) state or a translucent (light-blocking) state. In the light-blocking state, the interior of display module  12 A will be substantially hidden from view and the exterior surface of rear plate  26  will appear opaque or translucent. In the light-passing state, layer  26  may be sufficiently clear to allow a user to view an image or other light output from status light-emitting diodes or other light sources. 
     As shown in the example of  FIG. 22 , a rear-facing display such as a display formed from liquid-crystal display structures  196  may be formed under electrochromic glass layer  26  or in place of electrochromic glass layer  26 . Shared backlight  198  may serve as a backlight for both rear display structures  196  and front display structures  72 . For example, backlight  198  may include a light guide layer (see, e.g., plate  86  of  FIG. 5 ) and associated optical films (e.g., a rear polarizer, diffuser, etc.), but no reflectors. In this type of arrangement, light that is launched into the light guide layer will be scattered in the rear direction to serve as backlight for rear-facing display  196  and will be scattered in the front direction to serve as backlight for front-facing display  72  (i.e., display  18 ). Display structures  72  and  196  may include optional cover glass layers (e.g., on the front-facing display only, on the rear-facing display only, or on both the front-facing display structures and the rear-facing display structures), color filter layers, thin-film transistor layers, polarizer layers and other optical films, etc. If desired, electrochromic glass  26  may be omitted (e.g., to form a two-sided display without electrochromic properties). In arrangements such as these, optical films will be interposed between shared backlight  198  and the front and rear surfaces of housing  12 A. For example, optical film layers (e.g., polarizer layers, diffuser layers, and other optical films associated with display structures  196 ) will be interposed between the backlight layer of backlight unit  198  and the color filter layer and thin-film transistor layer of display structures  196 . Optical films such as these will also be interposed between the backlight layer of backlight  198  and the color filter layer and thin-film transistor layer of display structures  72 . 
     In configuration in which electrochromic glass is used, a user can view images that are presented on rear display  196  when the electrochromic glass is in its clear state. Control circuitry  36  can use paths  200  to provide signals such as control and data signals to glass  26  (e.g., to change the state of glass  26 ), to displays  196  and  72  (e.g., to direct displays  196  and  72  to display particular images), and to shared backlight  198  (to adjust the brightness of the light-emitting diodes associated with the backlight). Two-display housing configurations of the type shown in  FIG. 22  may, if desired, have individual backlight units. The use of a single common backlight for illuminating both front and rear displays may, however, help reduce display thickness and reduce device complexity. Displays  196  and  72  may, if desired, be touch screen displays (e.g., by incorporating arrays of touch screen electrodes such as transparent indium tin oxide capacitive electrodes for a capacitive touch screen). 
       FIG. 23  is a cross-sectional diagram of an illustrative configuration for display module  12 A in which display module  12 A has a single display (i.e., liquid crystal display structures  72 , which may or may not be touch sensitive). In this type of configuration, backlight for display structures  72  may be provided by backlight unit  102 . Back light may be delivered using light guide  86 . Reflector  84  may direct light that is emitted from the rear surface of light guide  86  back through display  72 . Some light may pass through reflector  84 . When electrochromic glass layer  26  is in its light-blocking state, the rear of display module  26  may appear dark. When electrochromic glass layer  26  is in its light-transmitting state, the light that passes through reflector  84  towards the rear of display module  12 A may pass unimpeded through electrochromic layer  26 . By adjusting the state of electrochromic glass  26 , device  10  can adjust the appearance of the rear surface of display housing  12 A (and, if desired, the rear surface of housing  12 B, which may also be provided with single-display and dual-display configurations of the types shown in  FIGS. 22 and 23 ). 
     Electrochromic layers such as layers  26  of  FIGS. 22 and 23  may extend over the entirety of the rear surfaces of housings  12 A and  12 B or, if desired, may be controlled in a more granular fashion. For example, device  10  may be provided with an electrochromic layer that is divided into multiple sections (e.g., halves, quarters, eighths, or other subsections of a full rear surface). This type of arrangement may be used when it is desired to control different areas of housing  12 A (or  12 B) individually (e.g., when it is desired to adjust illumination levels individually or when it is desired to make localized adjustments to form patterns such as logo  82 ). Patterned masking layers may be used to coat the inner surface of electrochromic glass layer  26  if desired. 
     As shown in  FIG. 24 , photovoltaic structures (sometimes referred to as solar cells or photovoltaic cells) may be placed under a glass layer or other rear plate  26 . For example, photovoltaic cells  202  may be interposed between a glass layer (rear plate)  26  and liquid crystal display structures  72  for display  18  ( FIG. 1A ). When device  10  is near a source of external illumination, such as light rays  200 , light rays  200  may pass through the glass or other transparent layer that forms rear plate  26 . Photovoltaic cells  202  may receive the light rays that pass through layer  26  and may convert this light into electrical power (e.g., 10 mW or more, 100 mW, 1 W or more, etc.) on path  204 . Path  204  may supply power from cells  202  to power circuits  32  ( FIG. 2 ) to power device  10  and/or to charge battery  34 . By charging battery  34  with battery charging power from path  204 , battery charge can be extended. 
     To ensure that display  18  is evenly illuminated, the back light unit that provides backlight for display  18  of  FIG. 1A  may be provided with light-emitting diodes that are arranged along more than one of the edges of the light guide layer in the back light unit. A top view of an illustrative layout that may be used for light-emitting diodes  92 L in backlight unit  102  of display  18  is shown in  FIG. 25 . Display  18  is rectangular and has left, right, top, and bottom edges. Arrays of light-emitting diodes for backlight unit  102  may be provided along one edge of display  18 , along two edges of display  18 , along three edges of display  18 , or along four edges of display  18 . 
     In the example of  FIG. 25 , backlight unit  102  of display  18  includes two rows of light-emitting diodes  92 L. Light-emitting diodes  92 L along the upper edge of display  18  launch backlight  116 A into light guide  86 . Light-emitting diodes  92 L along the lower edge of display  18  launch backlight  116 B into light guide  86 . In the  FIG. 25  example, only three light-emitting diodes are shown in each row to avoid over-complicating the drawing. In a typical display, there may be numerous light-emitting diodes (e.g., five or more, ten or more, twenty or more, etc.). The use of light-emitting diodes that are arranged along more than one of the edges of display  18  may help create more backlight and/or more evenly distributed backlight than arrangements in which only one edge of light guide  86  is provided with light-emitting diodes. Dividing light production between multiple sets of LEDs allows each LED set to be driven less aggressively, reducing deterioration (from heat, etc.) thereby improving LED life. This also permits smaller and thinner LEDs to be used, while maintaining performance of a single, larger set of LEDs. 
     In conventional backlight units, light-emitting diodes are soldered to the top of a flex circuit. This type of arrangement is shown in  FIG. 26 . As shown in  FIG. 26 , light-emitting diode  206  has terminals  208  that are soldered to traces  212  on flex circuit  214  using solder  210 . Light-emitting diode  206  rests on the upper surface of flex circuit  214 , so the total thickness of the  FIG. 26  assembly is equal to the sum of the flex circuit, light-emitting diode, solder pad, and terminal thicknesses. The thickness of conventional arrangements of the type shown in  FIG. 26  may not be acceptable in devices where space is at a premium. 
     To help minimize size in device  10 , light-emitting diodes  92 L may, if desired, be mounted upside down as shown in  FIG. 27 . With this type of configuration, substrate  92  may have openings such as opening  222  each of which receives a respective light-emitting diode  92 L. As shown in  FIG. 27 , conductive traces such as traces  220  may be formed on the surface of substrate  92 . Substrate  92  may be, for example, a ceramic substrate, a rigid printed circuit board substrate, or a flex circuit substrate. When light-emitting diode  92 L is inserted upside down so that the top of light-emitting diode  92 L rests within opening  222  of substrate  92 , terminals  216  of light-emitting diode  92 L may be connected to traces  220  using solder  218 , conductive adhesive, or other suitable electrically conducting materials. The total height of a light-emitting diode backlight assembly constructed in accordance with the arrangement of  FIG. 27  may be thinner than conventional arrangements of the type shown in  FIG. 26 , even if the thickness of substrate  92  is somewhat larger than conventional flex circuit substrates. 
     Openings  222  may have any suitable shape. An illustrative arrangement in which openings  222  are formed from open-sided rectangles (notches) formed along one edge of substrate  92  is shown in the top view of  FIG. 28 . Two light-emitting diodes  92 L are shown in the  FIG. 28  example, but in a typical light-emitting diode array for edge illuminating a back light unit, there may be five or more, ten or more, or twenty or more light-emitting diodes. The cross-sectional side view of  FIG. 27  corresponds to a cross-section taken along line  224  of  FIG. 28  viewed in direction  226 . 
     To minimize light scattering and thereby enhance the efficiency with which light enters light guide  86  from light-emitting diodes  92 L in backlight unit  102 , light guide  86  may be formed using an insert molding process. An illustrative insert molding process that may be used to construct backlight unit  102  in device  10  is shown in  FIGS. 29 ,  30 , and  31 . Initially, light-emitting diodes such as light-emitting diode  92 L may be mounted to a flex circuit or other substrate such as substrate  92  of  FIG. 29 . Traces on substrate  92  such as traces  220  of  FIG. 27  may be used to electrically connect the terminals of light-emitting diode  92 L to terminals  228  (e.g., metal pads or a circuit board connector). Light-emitting diodes  92 L may be soldered to substrate  92  or may be mounted to substrate  92  using conductive adhesive. 
     After light-emitting diodes  92 L have been mounted to substrate  92 , portion  242  of substrate  92  and light-emitting diodes  92 L may be inserted into the cavity of an insert molding tool, as shown in  FIG. 30 . Insert molding tool  246  may include mold portions such as upper mold portion  230  and lower mold portion  232 . Portion  242  may extend into cavity  240 , so that portion  242  and light-emitting diode  92 L may be covered with insert-molded material during insert molding operations. Insert molding material  236  may be formed from plastic or other suitable materials and may be inserted into cavity  240  through opening  234  in mold  232  from reservoir  238 . During molding operations, tool  246  may apply heat and pressure that molds material  236  over light-emitting diode  92 L and the exposed end of substrate  92  in cavity  240 . 
     Following the insert molding process and removal of the substrate  92  from tool  246 , light-emitting diodes  92 L are covered with material  236 . Cavity  240  can be configured so that the resulting shape of material  236  forms light guide  86 , as shown in  FIG. 31 . In light guide  86  of  FIG. 31 , light-emitting edge  244  of light-emitting diode  92 L is covered with a conformal layer of clear plastic (or other light guide material), so there are minimal coupling losses as light  116  exits light-emitting diode  92 L and enters planar light guide member  86 . 
     As shown in the exploded perspective view of housing  12 A in  FIG. 32 , display  18  and housing  12 A may have rounded corners. In particular, display structures  72  (e.g., an upper layer formed from a polarizer, color filter array layer, etc. and a lower layer formed from a thin-film transistor layer, or other suitable layers) may have one, two, three, or four curved corners such as curved corner  71 . Member  56  may have one, two, three, or four curved corners such as curved corner  55 . Shelf  64  of member  56  may have a one, two, three, or four curved corners such as curved corner  67  (e.g., that mate with curved corner  71  and that have a radius of curvature that is proportional to the radius of curvature of corner  71 ). Other structures within display  12 A may, if desired, be curved to accommodate the curved interior shape of member  56 . Rear plate  26  may likewise have one, two, three, or four curved corners such as corner  261  (e.g., that mate with the curved interior surface of member  56 ). 
       FIG. 33  is a cross-sectional side view of a portion of a housing for an electronic device (e.g., upper housing  12 A) showing how the peripheral edge of display structures  72  may be surrounded by a peripheral trim member such as trim member  150 . Trim member  150  may be formed from plastic, glass, ceramic, fiber composite materials, metal, or other materials. Display structures  72  may include color filter layer  72 A (or a polarizer on a color filter layer) and thin-film transistor layer  72 B. A cover glass layer and other display layers may also be incorporated into display structures  72  if desired. Display structures  72  may be mounted on the front of peripheral housing member  56  and rear plate  26  may be mounted on the rear of peripheral housing member  56  (as an example). With a configuration of the type shown in  FIG. 33 , the exterior surface of display structures  72  extends beyond surface S 1  of member  56  and the exterior surface of rear plate  26  extends beyond surface S 2  of member  56 , so that apparent thickness TH 1  of housing  12 A is thinner than actual thickness TH 2  of housing  12 A. 
     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: 20100824
Publication Date: 20140128
Grant Date: 20140128
Priority Date: 20100824
Inventors: GARELLI ADAM T.
MATHEW DINESH C.
WILSON, JR. THOMAS W.
HENDREN KEITH J.
AUGENBERGS PETERIS K.
DEGNER BRETT W.
HAMEL BRADLEY J.
DAMLANAKIS MICHAEL A.
KESSLER PATRICK
Assignee: APPLE INC
CPC Classifications: [{"code": "H04M1/0214", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01Q1/38", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/181", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/181", "inventive": true, "first": true, "tree": "[]"}, {"code": "H01Q1/38", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01Q1/42", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1626", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1615", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1626", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1615", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/0214", "inventive": false, "first": false, "tree": "[]"}, {"code": "H01Q1/42", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 45697006