PATENT DOCUMENT

Publication Number: US-8408780-B2
Application Number: US-69171410-A
Country: US
Kind Code: B2

Title: Portable computer housing with integral display

Abstract:
An electronic device such as a portable computer may have a housing with a rectangular recess in which layers of display structures such as a light guide panel layer and other light guide structures are directly mounted without intervening chassis members. Mating alignment features in the housing and display structures may be used to align the display structures relative to the housing. A display may be formed from glass layers such as a color filter glass layer and a thin-film transistor glass layer. Backlight for the display may be generated by an array of light-emitting diodes. The light guide panel may direct light from the light-emitting diodes through the glass layers. A clamp may be used to hold the light-emitting diodes and light guide structures in place in the recess. An undercut in the housing may also hold the light guide structures in place.

Claims:
What is claimed is: 
     
       1. Apparatus, comprising:
 a computer housing having a substantially rectangular recess with four edges; 
 a substantially rectangular light guide panel disposed in the rectangular recess, wherein the light guide panel has four edges that are adjacent to the four edges of the rectangular recess without any intervening chassis structures; 
 an array of light-emitting diodes that emit light into one of the edges of the light guide panel; 
 a flex circuit on which the light-emitting diodes are mounted; 
 reflective tape that covers at least part of the flex circuit; 
 a metal clamp over that light-emitting diode array; and 
 a strip of reflective material disposed between the light-emitting diode array and the metal clamp. 
 
     
     
       2. The apparatus defined in  claim 1  further comprising a clamp structure disposed over an edge of the light guide panel. 
     
     
       3. The apparatus defined in  claim 2  wherein the clamp structure comprises a sheet of metal. 
     
     
       4. The apparatus defined in  claim 2  wherein the clamp structure comprises a strip of stainless steel that is screwed into the computer housing. 
     
     
       5. The apparatus defined in  claim 1  wherein the light guide panel comprises at least one alignment tab and wherein the computer housing has at least one mating tab-shaped recess into which the alignment tab protrudes. 
     
     
       6. The apparatus defined in  claim 5  further comprising a reflective coating in the rectangular recess that reflects light back into the light guide panel. 
     
     
       7. The apparatus defined in  claim 6  wherein the reflective coating comprises white paint in the rectangular recess. 
     
     
       8. The apparatus defined in  claim 6  wherein the reflective coating comprises a layer of metal. 
     
     
       9. The apparatus defined in  claim 1  further comprising a white reflective sheet disposed between the light guide panel and the recess in the computer housing, wherein the white reflective sheet has portions that cover at least one of the edges of the light guide panel. 
     
     
       10. The apparatus defined in  claim 1  wherein the computer housing comprises machined aluminum. 
     
     
       11. The apparatus defined in  claim 1  further comprising:
 a thin-film transistor glass layer; and 
 a color filter glass layer, wherein the thin-film transistor glass layer and the color filter glass layer are positioned above the rectangular recess and wherein light from the light guide panel passes through the thin-film glass layer and the color filter glass layer. 
 
     
     
       12. The apparatus defined in  claim 1  wherein the light guide panel comprises at least one alignment tab, wherein the computer housing has at least one mating tab-shaped recess into which the alignment tab protrudes, wherein the apparatus further comprises layers of optical films including a diffuser layer, and wherein the layers of optical films each include at least one alignment tab that protrudes into the tab-shaped recess in the computer housing. 
     
     
       13. The apparatus defined in  claim 12  further comprising a plastic reflective sheet under the light guide panel, wherein the plastic reflective sheet has bent edges that cover at least two of the edges of the light guide panel. 
     
     
       14. The apparatus defined in  claim 1  further comprising:
 glass layers through which light from the light guide panel passes; and 
 a bezel that covers at least part of the glass layers. 
 
     
     
       15. The apparatus defined in  claim 1  further comprising a sheet of reflective material under the light guide panel, wherein at least a portion of the sheet of reflective material covers the flex circuit. 
     
     
       16. A computer, comprising:
 a housing having a base unit hingedly connected to a display housing wherein the display housing comprises a machined rectangular recess having four recess edges and having alignment notches disposed along at least two of the four recess edges; and a rectangular light guide panel having at least four light guide panel edges and having alignment tabs disposed along at least two of the four light guide panel edges, wherein the alignment taps protrude into and mate with the alignment notches in the display housing; 
 a color filter glass layer through which light from the rectangular light guide panel passes; 
 a white reflective sheet with tabs that mate with the alignment notches; 
 at least one optical film layer on the light guide panel, wherein the at least one optical film layer includes a diffuser layer with tabs that mate with the alignment notches; 
 light-emitting diodes that emit light into a given one of the edges of the light guide panel; and 
 a metal clamp structure that is screwed into the housing along one of the four recess edges and that covers the light-emitting diodes and the given one of the edges of the light guide panel.

Description:
This application claims the benefit of provisional patent application No. 61/257,807, filed Nov. 3, 2009, which is hereby incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     This invention relates to electronic devices and, more particularly, to display structures for electronic devices such as portable computers. 
     Portable computers typically have upper and lower housing portions that are connected by a hinge. The lower housing portion contains components such as printed circuit boards, disk drives, a keyboard, and a battery. The upper housing portion contains a display. When the computer is in an open configuration, the upper housing portion is vertical and the display is visible to the user of the portable computer. When the computer is closed, the upper housing lies flat against the lower housing. This protects the display and keyboard and allows the portable computer to be transported. 
     Portable computer displays typically contain fragile structures such as layers of glass. Displays can therefore be challenging to mount properly within the upper housing. If care is not taken, the display and the surrounding portions of the upper housing will be bulky and unsightly. At the same time, the elimination of certain structures in the display may result in display that is overly fragile. This could lead to damage to the display during normal use. 
     It would therefore be desirable to be able to provide improved display structures in electronic devices such as portable computers. 
     SUMMARY 
     An electronic device such as a portable computer may have a housing. The housing may have upper and lower portions that are connected by a hinge. Display structures for a display may be mounted in a portion of the housing such as the upper housing portion. 
     The display structures may include a color filter glass layer and a thin-film transistor substrate layer. Light-guide structures may be mounted under the thin-film transistor substrate layer. The light guide structures may include a reflective sheet of material such as white polyester (e.g., Mylar®), a layer of light guide material (sometimes referred to as a light guide panel or LGP), and one or more layers of optical film (e.g., diffuser layers, light collimating layers, etc.). The light guide structures may be mounted directly in a rectangular recess in the interior of the housing without using chassis structures. For example, the light guide structures may be provided with tabs that mate directly with corresponding features in the housing. 
     Undercut structures may be formed in the housing to accommodate the display structures. For example, the undercut structures may receive some or all of the light guide structures. 
     An array of light-emitting diodes may provide backlight for the display structures. The light-emitting diodes may emit light into an edge of the light guide panel. A reflective sheet on the rear of the light guide panel may be used to reflect light outwards through the display structures. The edges of the reflective sheet may be wrapped around the edges of the light guide panel to reflect light that would otherwise leak out of the edges of the panel. Light may also be reflected by coating interior housing surfaces with a reflective coating. 
     Clamp structures may be used to hold the light-emitting diode array and light-guide panel in place. 
     Reflective tape and reflective sheets of material may be used to help guide light from the light-emitting diode array into the edge of the light guide panel. Reflective tape may be placed on the lower surface of a clamp member. 
     A cosmetic bezel may be used to cover edges of the display structures. For example, in display structure configurations in which a driver integrated circuit might be visible from the exterior of the device, a bezel may be used to hide the integrated circuit from view. 
     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 portable computer with display structures in accordance with an embodiment of the present invention. 
         FIG. 2  is a cross-sectional side view of a conventional liquid crystal display (LCD) module in a portable computer display housing. 
         FIG. 3  is a cross-sectional side view of an edge portion of a conventional LCD module. 
         FIG. 4  is an exploded view of a conventional computer housing and conventional display structures. 
         FIG. 5  is a cross-sectional side view of a conventional light-emitting-diode array in a conventional display module. 
         FIG. 6  is a perspective view of conventional light-emitting-diodes mounted on a flex circuit. 
         FIG. 7  is a cross-sectional side view of conventional backlight component in a conventional computer housing. 
         FIG. 8  is a cross-sectional side view of illustrative display structures in an electronic device such as a portable computer in accordance with an embodiment of the present invention. 
         FIG. 9  is an exploded view showing how display components may be mounted directly in a recess in a computer housing in accordance with an embodiment of the present invention. 
         FIG. 10  is a top view of a computer housing in which a ledge has been formed to ensure that a light guide panel does not damage an associated array of light-emitting diodes in accordance with an embodiment of the present invention. 
         FIG. 11  is a cross-sectional side view of illustrative display structures in an electronic device such as a computer in which a device housing has been provided with an undercut groove portion to accommodate an edge of a light guide panel and other light guide components in accordance with an embodiment of the present invention. 
         FIG. 12  is a perspective view showing how light guide components may have alignment features such as tabs that mate with corresponding housing alignment features such as tab-shaped recesses in accordance with an embodiment of the present invention. 
         FIG. 13  is a perspective view showing how a reflective layer may be wrapped around the back and edges of a light guide panel to ensure that light is reflected back into the panel in accordance with an embodiment of the present invention. 
         FIG. 14  is a perspective view of a portion of an electronic device housing showing how a clamp structure may be used to help retain an array of light emitting diodes while reflecting and guiding light that is produced by the light emitting diodes in accordance with an embodiment of the present invention. 
         FIG. 15  is a cross-sectional side view of an illustrative electronic device showing how a planar clamp structure may be used to help retain an array of light emitting diodes in accordance with an embodiment of the present invention. 
         FIG. 16  is a cross-sectional side view of a light-emitting diode array showing how a reflective sheet may be placed over the edge of the light-emitting diode flex circuit in accordance with an embodiment of the present invention. 
         FIG. 17  is a cross-sectional side view of a light-emitting diode array showing how reflective tape may be placed over the edge of the light-emitting diode flex circuit and under the edge of a reflective sheet in accordance with an embodiment of the present invention. 
         FIG. 18  is a cross-sectional side view of a light-emitting diode array showing how a reflective coating such as reflective paint may be used to reflect light in accordance with an embodiment of the present invention. 
         FIG. 19  is a cross-sectional side view of a light-emitting diode array showing how exposed interior surfaces of a computer housing may be coated with reflective coating such as reflective paint in accordance with an embodiment of the present invention. 
         FIG. 20  is a cross-sectional side view of an illustrative electronic device such as a computer in which a bezel is used in covering display structures in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     An illustrative electronic device such as a portable computer in which display structures may be provided is shown in  FIG. 1 . As shown in  FIG. 1 , portable computer  10  may have housing  12 . Housing  12 , which is sometimes referred to as a case, may be formed from one or more individual structures. For example, housing  12  may have a main structural support member that is formed from a solid block of machined aluminum or other suitable metal. One or more additional structures may be connected to the housing  12 . These structures may include, for example, internal frame members, external coverings such as sheets of metal, etc. Housing  12  and its associated components may, in general, be formed from any suitable materials such as such as plastic, ceramics, metal, glass, composites, etc. An advantage of forming housing  12  at least partly from metal is that metal is durable and attractive in appearance. Metals such as aluminum may be anodized to form an insulating oxide coating. 
     In general, the components of portable computer  10  can be formed from any suitable materials. As examples, the components of portable computer  10  may be formed from materials such as metals (e.g., aluminum, stainless steel, alloys of metals, electroplated metals, plated and other coated metals, etc.), plastics (e.g., polycarbonate (PC) plastics, acrylonitrile butadiene styrene (ABS) plastics, thermoplastics, PC/ABS plastic blends, etc.), composite materials (e.g., carbon fibers or other fibers bound by a binder such as a polymer resin), plastics that have been injection molded around metal structures, laminated plastic layers, ceramics, metal, glass, composites, metal-filled epoxy, other suitable materials, and combinations of these and other materials. Components of portable computer  10  which are described herein as being formed from one or more specific materials (e.g., housing  12  which is sometimes described herein as being formed from machined aluminum as an example) can be formed from any of the above-mentioned materials, other suitable materials, or combinations of such materials. 
     Housing  12  may have an upper portion  26  and a lower portion  28 . Lower portion  28  may be referred to as the base or main unit of computer  10  and may contain components such as a hard disk drive, battery, and main logic board. Upper portion  26 , which is sometimes referred to as a cover, lid, or display housing, may rotate relative to lower portion  28  about rotational axis  16 . Portion  18  of computer  10  may contain a hinge and associated clutch structures and is sometimes referred to as a clutch barrel. 
     Lower housing portion  28  may have a slot such as slot  22  through which optical disks may be loaded into an optical disk drive. Lower housing portion may also have a touchpad such as touchpad  24  and may have keys  20 . If desired, additional components may be mounted to upper and lower housing portions  26  and  28 . For example, upper and lower housing portions  26  and  28  may have ports to which cables can be connected (e.g., universal serial bus ports, an Ethernet port, a Firewire port, audio jacks, card slots, etc.). Buttons and other controls may also be mounted to housing  12 . Speaker openings such as speaker openings  30  may be formed in lower housing portion  28  by creating an array of small openings (perforations) in the surface of housing  12 . 
     A display such as display  14  may be mounted within upper housing portion  26 . Display  14  may be, for example, a liquid crystal display (LCD), organic light emitting diode (OLED) display, or plasma display (as examples). Display  14  may contain a number of layers of material. These display structures may include, for example, layers of optically transparent materials such as plastic and glass. Layers of plastic and optical adhesive may also be incorporated into display  14 . In a liquid crystal display, layers of polarizer, light diffusing elements and light guides for backlight structures, a liquid crystal layer, and a thin-film transistor array that drives the image pixels in the display may be incorporated into the display. 
     Computer  10  may have input-output components such as touch pad  24 . Touch pad  24  may include a touch sensitive surface that allows a user of computer  10  to control computer  10  using touch-based commands (gestures). A portion of touchpad  24  may be depressed by the user when the user desires to “click” on a displayed item on screen  14 . 
     A cross-sectional side view of a conventional liquid crystal display (LCD) display module mounted in a computer housing is shown in  FIG. 2 . As shown in  FIG. 2 , display module  32  may have display structures  46  such as an upper polarizer layer, a color filter, a thin-film transistor glass layer, a lower polarizer, and a layer of light-guide structures. The light guide structures may include a reflective bottom sheet, a light guide panel that guides light from an array of edge-mounted light-emitting diodes over the full surface area of the display, and layers of optical films such as diffuser layers. Display module  32  may also have a plastic chassis member such as plastic chassis member  44  and a metal chassis member such as metal chassis member  42  into which the layers of glass and other display module structures may be mounted. Cover glass  36  may be placed on top of structures  46 . 
     Metal chassis member  42  may have a tab with a hole through which screw  40  passes. Screw  40  may be screwed into a threaded hole in housing  34 . In the arrangement of  FIG. 2 , housing  34  is formed of aluminum. The presence of the extending tab portion of chassis  42  allows module  32  to be firmly secured in housing  34 , but adds undesirable width to the perimeter of display module  32 . 
     Elastomeric gasket  38  is used to form a cushioned interface between cover glass layer  36  and housing  34 . This helps to prevent damage to cover glass layer  36 . Cover glass  36  is formed from clear glass and helps to protect layers  46  of LCD module  32  from damage, but adds undesirable thickness. 
     Another cross-sectional view of a conventional liquid crystal display module is shown in  FIG. 3 . As shown in  FIG. 3 , display module  32  may have polarizers such as upper polarizer layer  50  and lower polarizer  62 . Light guide structure  64  may provide backlight for module  32 . The light from structure  64  passes through the display pixels of module  32  and exits display module  32  in direction  31 . 
     Color filter glass layer  52 , liquid crystal layer  54 , and thin-film transistor (TFT) glass layer  58  are interposed between polarizer layers  50  and  62 . 
     The polarization of individual pixels of liquid crystal material in liquid crystal layer  54  interacts with the polarizing effects of layers  50  and  62  to determine which display pixels block light and which pixels allow light to pass. Color filter glass layer  52  contains an array of colored filters that provide display  32  with the ability to represent different colors. The polarization of liquid crystal material in liquid crystal layer  54  is controlled electrically by thin-film transistor array  56 . Thin-film transistors in array  56  are formed on the upper surface of thin-film transistor (TFT) glass layer  58 . 
     Thin-film transistors  56  are controlled by drivers contained in driver circuit  60 . Color filter layer  52  is horizontally (laterally) recessed with respect to TFT layer  58  to form a ledge on which driver circuit  60  is mounted. In a typical display module, there may be a number of driver chips such as circuit  60  that are mounted around the periphery of the display. Conductive traces on the upper surface of TFT layer  58  interconnect driver circuit  60  with thin-film transistors  56 . 
     In conventional arrangements of the type shown in  FIG. 3 , black ink  48  is placed on the underside of cover glass  36  around the periphery of the display. This creates an opaque region that blocks inactive peripheral portions of display module  32  from view. Black ink  48  can also hide mounting structures such as screw  40  of  FIG. 2  from view. Display glass  36  may help provide structural support to the display housing of the portable computer in which display module  32  is mounted, but the presence of glass  36  can add a non-negligible amount of extra thickness and weight to a display. 
     An exploded view of a conventional display and computer housing is shown in  FIG. 4 . As shown in  FIG. 4 , light guide structures  64  may have tabs  68  that mate with recesses in plastic chassis  44 . Light-emitting diode array  66  is covered with plastic chassis parts in regions  72 . In region  74 , part of metal chassis  42  (shown as metal chassis portion  42 ′) is bent up and over the light-emitting diode array to hold the array in place. Chassis  42  and chassis  44  may be mounted in housing  34 . 
     A cross-sectional side view of the conventional structures of  FIG. 4  taken along line  76 - 76  of  FIG. 4  is shown in  FIG. 5 . As shown in  FIG. 5 , light guide structures  64  include reflective polyester sheet  80  (e.g., white polyester), light-guide panel  82 , and optical films  84 . Metal chassis portion  42 ′ covers light-emitting diode array  66 . Light-emitting diode array  66  contains light-emitting diodes that provide backlight for the display. The light-emitting diode chips are mounted on flexible printed circuit (“flex circuit”)  78 . The edge of reflective sheet  80  covers the edge of flex circuit  78 . 
       FIG. 6  shows a perspective view of a conventional light-emitting diode array containing light-emitting diodes  66  and flex circuit substrate  78 . 
     Conventional light guide structures  64  may be provided with a peripheral strip of double-sided tape, as shown by tape  86  in  FIG. 7 . 
       FIG. 8  shows a cross-sectional side view of a portion of upper housing  26  of device  10  ( FIG. 1 ) in which display structures  106  have been mounted. Upper housing  26  may, for example, be formed from machined aluminum. Elastomeric gasket  104  may be used to provide a soft interface between potentially fragile glass layers in structures  106  and housing  26 . 
     Display structures  106  may produce an image using any suitable display technology (e.g., light-emitting diodes such as an array of organic light-emitting diodes, liquid crystal display pixels, plasma-based pixels, etc.). In general, display structures  106  may be formed from any suitable materials (e.g., plastic, glass, other optically suitable materials, etc.). An arrangement in which display structures  106  are based on liquid crystal display (LCD) technology is sometimes described herein as an example. The use of LCD structures in display structures  106  is, however, merely illustrative. Display structures  106  may, in general, be formed from any suitable type of display structures. 
     As shown in  FIG. 8 , display structures  106  may have an upper polarizer layer  102  and a lower polarizer layer  96 . Light guide structures  88  may provide backlight for structures  106 . Light-guide structures  88  may include reflective structures such as reflective sheet  90  (e.g., white polyester), light-guide panel  92 , and optical films  94 . Optical films  94  may include a diffuser layer and light collimating layers (as an example). If desired, light reflection functions may be provided by housing  26 . Housing  26  may be formed from a reflective material such as metal and/or the interior surfaces of housing  26  may be coated with a reflective coating such white paint or ink, silver paint or ink, a reflective material such as chromium, etc. In arrangements in which housing  26  is highly reflective, some or all of reflective sheet  90  may be omitted. 
     Clearances D 2  and D 1  help prevent damage to display structure  106  during use of device  110 . In a typical arrangement, clearance D 2  may be about 1.2 to 1.8 mm and clearance D 1  may be about 0.11 mm. End clearance D 3  may be about 0.3 mm. 
     Light from a light-emitting diode array or other backlight source is provided to an edge of light guide panel  92 . Panel  92  and the other structures in light guide structures  88  direct this light upwards in direction  108  through thin film transistor layer  98  and color filter layer  100 . 
     Thin-film transistor substrate glass layer  98  may contain thin-film transistors in array  110 . Color filter glass layer  100  may contain an array of optical filters of different colors to provide display structures  106  with the ability to display color images. Color filter layer  100  may be formed from glass into which dye of different colors has been impregnated, from a glass layer coated with a pattern of colored dye, from a glass or plastic layer that is covered with a pattern of thin colored filter structures (e.g., filters formed from polymer or glass containing dye), or any other suitable color filter structures. Liquid crystal layer  112  may be controlled by the electric fields produced by the thin-film transistors of array  110 . 
     As shown in  FIG. 8 , the layer of cover glass that is present in conventional display modules need not be present in display structures  106  and device  10 . Rather, color filter layer  100  may serve as the uppermost glass layer in structures  106  and device  10 . To ensure that structures  106  are sufficiently robust, color filter layer  100  may be thickened or may be stiffened using support structures within display structures  106 . Color filter layer  100  may be formed of a durable clear layer (e.g., a strong glass or plastic) that resists damage from contact. Anti-scratch coatings may also be provided on the surface of color filter layer  100  (e.g., as part of polarizer layer  102  or above polarizer layer  102 ). 
     To hide the peripheral portions of display structures  106  that lie along the outer edges of display housing  26  from view, an opaque material such as ink layer  114  may be incorporated around the periphery of display structures  106  to form a border. Opaque layer  114  may be formed on the underside of color filter layer  100  or on the upper surface of thin-film transistor glass layer  98  (as examples). The opaque material may have any suitable color (e.g., black, grey, silver, white, blue, red, etc.). 
     With the arrangement of  FIG. 8 , color filter layer  100  and thin-film transistor layer  98  extend outwardly (in the leftward direction in the orientation of  FIG. 8 ) so as to form an overhanging portion  116  that is supported by the matching ledge in housing  26 . If desired, only color filter layer  100  may extend in this way (e.g., so that the overhanging portion of layer  100  rests on the ledge formed by housing  26 ). In this type of arrangement, the thin-film transistor layer may extend only as far as light-guide structures  88  of  FIG. 8 . If desired, portions of gasket  104  may be interposed between display structures  106  and housing  26  in region  116 , as illustrated by protruding lower lip portion  105  of gasket  104  in the example of  FIG. 8 . Display driver circuitry  118  may, if desired, be formed in region  116  (e.g., as part of thin film transistor layer  98  or in a chip mounted on thin film transistor layer or color filter layer  100 ). 
     To ensure that light guide structures  88  are properly aligned within housing  26  even in the absence of conventional structures such as plastic chassis  44  and metal chassis  42  ( FIG. 2 ), housing  26  may be provided with alignment features such as rectangular recesses  122  of  FIG. 9  that mate with corresponding alignment features on light guide structures  88  such as protruding tabs  120  of  FIG. 9 . When housing  26  is formed by a molding process (e.g., plastic injection molding), alignment features can be molded into housing  26  as part of the housing fabrication process. When housing  26  is formed by a machining process (e.g., a process in which an aluminum block or other block of material is machined using a computer-controlled machining tool), alignment features can be machined directly into the aluminum housing. In the example of  FIG. 9 , there are four alignment tabs  120  and four corresponding housing pockets  122 . This is merely illustrative. There may be one tab and one recess, two or more tabs and recesses, etc. 
     Light-emitting diode array  122  may be received within recess  124  in housing  26 . Rectangular recess  134  in housing  26  may be sized to receive the rectangular outline of light guide structures  88 . The depth of these recesses in housing  26  may be about 0.2 mm to 5 mm (as an example). The diagonal distance across the rectangular light guide structures  88  may be, for example, 5 to 20 inches. 
     With an arrangement of the type shown in  FIG. 9 , recesses  122  and tabs  120  may help align light guide in recess  134 . For example, tabs may hold at least one of the edges of light guide structures  88  at a slight distance (clearance) from housing  26  to avoid creating pressure that might otherwise buckle light guide structures  88 . Along edge  136  structures  88  may, if desired, protrude under a lip in housing  26  (i.e., a lip that forms a capturing groove). This optional lip (groove) may help retain light guide structures  88  in housing  26  (e.g., by receiving and retaining the edge of light guide structures  88 ). Along edge  138  of housing  26 , clamp structure  130  may be used to help retain light guide structures  88  and light-emitting diode array  122  in housing  26 . Clamp structure  130  may be secured to housing  26  using adhesive, fasteners such as screws  132 , or other suitable attachment mechanisms. Screws  132  may pass through holes  128  in clamp  130  and may be received in threaded holes  126  in housing  26  (as an example). Clamp structure  130  may be formed in a single piece (as shown in  FIG. 9 ) or one or more separate members may be used in forming clamp structure  130 . 
     Clamp structure  130  may be formed from metal, plastic, composites, or other materials. For example, clamp structure  130  may be formed from a material such as stainless steel. Stainless steel can be formed in thin sheets that are relatively stiff, allowing the thickness of clamp structure  130  to be minimized. Housing  26  may be formed from aluminum or one or more other materials that are molded or machined into a desired shape (e.g., to form the alignment tab recesses of  FIG. 9  and the rectangular recess that receives rectangular light guide structures  88 ). 
     To help ensure that light guide structures  88  do not bear against light-emitting diode array  122  with excessive force, recess  134  may have lips such as lip  140 . As shown in more detail in  FIG. 10 , lip  140  of housing  26  may help prevent edge  142  of light guide structures  88  from directly contacting light-emitting diode array  122 . The nominal clearance D 4  between edge  142  and light-emitting diodes  122  may be, for example, 0 mm to 1 mm. 
     As shown in  FIG. 11 , a portion of housing  26  (e.g., the portion along edge  134 ) may be provided with an undercut. In region  148 , for example, lip  144  may extend outwards over undercut opening  146  to form a groove. Groove opening  146  may receive the edge of light guide structures  88 , allowing the edge of housing  26  that surrounds display structure  106  to be narrowed. 
     A perspective view of one of recesses  122  (i.e., an alignment notch) and one of matching tabs  120  on light guide structures  88  is shown in  FIG. 12 . A strip of tape  150  with a layer of adhesive  152  may be placed over tabs  120 . The tape may stick to housing  26  in regions  154  to hold tabs  120  in place in recess  122 . Tape  150  may be removed to permit rework. If desired, recesses  122  may be provided with integral housing lips (i.e., recesses  122  may be implemented as covered notches rather than as exposed notches). This may help avoid the need for tape strips  150 , but may require that light guide structures  88  be flexed slightly as part of the assembly process (i.e., to tuck tabs  120  into the covered notches and any grooves in the housing). 
     Light-emitting diodes  122  ( FIG. 9 ) emit light into the edge of light-guide panel  92 . Light guide panel  92  directs the emitted light upwards through layers such as layers  98  and  100 . To increase backlight efficiency, light leakage at the edges of light guide panel  92  should be minimized. With one suitable arrangement, the side walls of housing recess  134  that surround the edges of light guide panel  92  and the other light guide structures  88  may be machined to form a reflective surface or may be coated with white paint, chromium, or other reflective coatings. With another suitable arrangement, which is shown in  FIG. 13 , the edges of reflective sheet  90  (i.e., edges  156  and  158 ) may be wrapped upwards so as to surround the edges of light guide panel  92  and optical films  94 . By reflecting light back into the edges of light guide panel  92 , backlight that would otherwise be wasted is properly directed through the display. 
     In arrangements of the type shown in  FIG. 13 , reflective sheet  90  and wrapped reflective sheet edges  156  and  158  are formed from a unitary piece of material. If desired, separate layers of reflective material may be used for the main rear reflective sheet layer and for the reflective edges (as an example). 
     A perspective view of an illustrative clamping arrangement in which reflective tape is used to help ensure satisfactory backlight performance is shown in  FIG. 14 . Clamp  130  has bends  162  that allow clamp  130  to pass over housing structures such as wall  166 . Screws  132  may pass through holes  128  and into threaded holes  126  in housing  26  to hold clamp  130  in place over light-emitting diodes  122 . A strip of reflective material such as reflective tape  160  may be attached along edge  164  of clamp  130 . Tape  160  may help to reflect light from diodes  122  into the edge of light guide panel  92 . 
     A cross-sectional side view of an illustrative mounting arrangement that uses a planar clamp is shown in  FIG. 15 . As shown in  FIG. 15 , driver circuitry  118  may be implemented using separate integrated circuits (as an example). Planar clamp structure  130  may be attached to housing  26  using screws such as screw  132 . Reflective tape  160  may be placed above light-emitting diodes  122  to help guide light  172  into the edge of light guide panel  92 . Reflective sheet  90  may be placed below the lower surface of light guide panel  92  to reflect escaping light back into light guide panel  92 . Additional reflective structures such as reflective tape  170  may provide further light reflection. Light-emitting diodes  122  may be mounted on a substrate such as flex circuit  168 . Tape  170  can be placed over the edge of flex circuit  168  as shown in  FIG. 15 . 
     If desired, the edge of reflective sheet  90  may overlap the edge of flex circuit  168 . This type of arrangement is shown in  FIG. 16 . 
       FIG. 17  shows how tape  170  may have one edge that is placed over flex circuit  168  and one edge that is placed under reflective sheet  90  (as shown in the example of  FIG. 15 ). 
     Light may also be reflected using reflective coatings. For example, tape  170  may be omitted and flex circuit  168  may be coated with reflective coating  174 , as shown in  FIG. 18 . Coating  174  may be formed from reflective coating such as white paint or white ink, from a shiny substance such as a metallic paint or a metal coating, or other reflective materials. 
     In the illustrative configuration of  FIG. 19 , housing  26  has been provided with reflective coating  174 . Some of reflective coating  174  has also been formed over exposed edge  176  of flex circuit  168 . Reflective coating  174  may be formed by physical vapor deposition (e.g., sputtering), by silk screen printing, pad printing, spray coating, electrochemical deposition, electroplating, manual application with a paint brush or foam pad, ink jet printing, etc. 
     If desired, a bezel may be used in covering display components. This type of arrangement is shown in  FIG. 20 . As shown in  FIG. 20 , bezel  178  may cover edge portions of display structures  106 . Bezel  178  may be formed from plastic, glass, metal, composites, other suitable materials, or combinations of these materials. Driver circuitry  188  may be provided in the form of integrated circuits mounted on layer  98  or mounted on layer  100  or driver circuitry  188  may be provided in the form of circuitry integrated on layer  98  or on layer  100  (as examples). By using bezel  178 , internal device structures such as circuitry  188  may be hidden from view from the exterior of device  10 . Adhesive such as adhesive  180  may be used to attach bezel  178  to housing  26 . Adhesive  182  may be used to attach display structures  106  to housing  26 . 
     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: 20100121
Publication Date: 20130402
Grant Date: 20130402
Priority Date: 20091103
Inventors: MATHEW DINESH C.
WILSON, JR. THOMAS W.
YIN VICTOR H.
POSNER BRYAN W.
LIGTENBERG CHRIS
DEGNER BRETT W.
AUGENBERGS PETERIS K.
GARELLI ADAM
Assignee: APPLE INC
CPC Classifications: [{"code": "G06F1/1616", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B6/0033", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1616", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B6/0031", "inventive": true, "first": false, "tree": "[]"}, {"code": "Y10T29/49002", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1637", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1637", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B6/0073", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B6/0011", "inventive": true, "first": true, "tree": "[]"}, {"code": "Y10T29/49002", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 43925248