PATENT DOCUMENT

Publication Number: US-9990001-B2
Application Number: US-201514754455-A
Country: US
Kind Code: B2

Title: Electronic device display structures

Abstract:
An electronic device may have a housing in which a display is mounted. A gasket may be mounted in a groove between the display and housing. The gasket may contain an embedded stiffener. Corner brackets may be installed in the corners of the housing. The housing may have inner and outer concentric ribs. Recesses in the housing may be configured to receive the corner brackets. The recesses may be formed between the inner and outer concentric ribs. Gap filling structures such as a foam layer may be interposed between a rear housing wall and a display backlight unit. Display color variations may be corrected by using a backlight unit having an array of light-emitting diodes of different colors. An electrostatic discharge protection layer may be grounded to a housing using conductive tape. Black edge coatings and adhesive-based structures may block stray light. Camera window regions may be supported using adhesive.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a sheet metal corner bracket having opposing upper and lower surfaces surrounded by a peripheral edge; 
 a housing having a corner with a recess that receives the sheet metal corner bracket such that the housing surrounds the peripheral edge of the sheet metal corner bracket, wherein the housing has inner and outer ribs and wherein the recess is formed between at least part of the inner and outer ribs; and 
 a display mounted in the housing, wherein the display overlaps the inner and outer ribs, and wherein the display is fixed relative to the inner rib and free to move relative to the outer rib. 
 
     
     
       2. The electronic device defined in  claim 1  further comprising adhesive that is interposed between the display and the inner rib to attach the display to the housing. 
     
     
       3. The electronic device defined in  claim 2  wherein the outer rib is free of adhesive and wherein the adhesive comprises part of an adhesive-based attachment structure that includes an upper adhesive layer, a lower adhesive layer, and a layer of foam interposed between the upper and lower adhesive layers. 
     
     
       4. The electronic device defined in  claim 1  wherein the housing has a planar wall structure, the electronic device further comprising:
 a display mounted in the housing; 
 a backlight unit mounted between the housing and the display, wherein the backlight unit is separated from the planar wall structure by a gap; and 
 a gap filling structure interposed between the planar wall structure and the backlight unit. 
 
     
     
       5. The electronic device defined in  claim 4  wherein the gap filling structure comprises a plastic structure. 
     
     
       6. The electronic device defined in  claim 4  wherein the gap filling structure comprises a layer of foam. 
     
     
       7. The electronic device defined in  claim 1  wherein the housing is formed from metal that is weaker than the sheet metal corner bracket. 
     
     
       8. The electronic device defined in  claim 1  wherein the housing has a lid portion in which a planar wall structure is formed and has a base portion and wherein the lid portion is attached to the base portion so that the lid portion rotates relative to the base portion. 
     
     
       9. An electronic device, comprising:
 a housing having corners and having an inner raised edge portion and an outer raised edge portion; 
 a metal member located at one of the corners between the inner raised edge portion and the outer raised edge portion, wherein the inner raised edge portion and the outer raised edge portion are formed from a continuous loop of material that extends around an entire periphery of the metal member, and wherein a shape of the continuous loop of material matches a shape of the metal member; 
 a display mounted in the housing; and 
 an attachment structure that attaches a portion of the display to the inner raised portion, wherein the display is allowed to move freely relative to the outer raised edge portion. 
 
     
     
       10. The electronic device defined in  claim 9  wherein the metal member comprises a corner bracket. 
     
     
       11. The electronic device defined in  claim 9  wherein the attachment structure comprises adhesive. 
     
     
       12. The electronic device defined in  claim 11  wherein the attachment structure comprises an opaque layer. 
     
     
       13. The electronic device defined in  claim 11  wherein the display covers the inner raised edge portion and the outer raised edge portion of the housing. 
     
     
       14. An electronic device, comprising:
 a housing having first and second raised portions that together define a recess; 
 a corner bracket in the recess; 
 a display mounted in the housing over the first and second raised portions, wherein the display covers the recess; and 
 an adhesive-based attachment structure that attaches the display to the first raised portion, wherein the display is allowed to move freely relative to the second raised portion. 
 
     
     
       15. The electronic device defined in  claim 14  wherein the adhesive-based attachment structure comprises a rectangular ring of adhesive-based material. 
     
     
       16. The electronic device defined in  claim 14  wherein the second raised portion of the housing is free of adhesive. 
     
     
       17. The electronic device defined in  claim 14  wherein the corner bracket comprises sheet metal. 
     
     
       18. The electronic device defined in  claim 14  wherein the housing comprises first and second housing structures, wherein the first housing structure rotates with respect to the second housing structure, and wherein the display is mounted in the first housing structure. 
     
     
       19. The electronic device defined in  claim 14  further comprising a conductive layer in the display and a conductive tape electrically coupled to the conductive layer.

Description:
This application is a division of U.S. patent application Ser. No. 13/629,503, filed Sep. 27, 2012, which claims the benefit of U.S. provisional patent application No. 61/657,232, filed Jun. 8, 2012. This application claims the benefit of and claims priority to U.S. patent application Ser. No. 13/629,503, filed Sep. 27, 2012, and U.S. provisional patent application No. 61/657,232, filed Jun. 8, 2012, which are hereby incorporated by reference herein in their entireties. 
    
    
     BACKGROUND 
     This invention relates to electronic devices and, more particularly, to structures for electronic devices such as display structures. 
     Electronic devices such as portable computers and cellular telephones typically have displays. It can be challenging to incorporate display structures into an electronic device. If care is not taken, electronic device display structures will be undesirably bulky or may have performance problems associated with display robustness, color uniformity, electrostatic discharge protection, and component integration. 
     It would therefore be desirable to be able to provide improved display structures in electronic devices. 
     SUMMARY 
     An electronic device may have a housing such as a metal housing. A display such as a liquid crystal display may be mounted within the housing. A groove may separate the housing from the display. A gasket may be mounted within the groove. The gasket may be formed from an elastomeric material. A recess in the gasket may be configured to receive an edge of the display. The gasket may have protrusions such as a lower protrusion that is attached to the housing of the electronic device with adhesive and an upper protrusion that covers an edge portion of the surface of the display. A portion of the gasket may contain an embedded stiffener such as a metal stiffening structure. 
     Corner brackets formed from sheet metal members may be installed in the corners of the housing. The housing may have inner and outer concentric ribs. Recesses in the housing may be configured to receive the corner brackets. The recesses may be formed between the inner and outer concentric ribs. 
     Gap filling structures may be interposed between a rear housing wall in an electronic device housing and a display backlight unit associated with a display. A gap filling structure may be formed from plastic member or a layer of foam. 
     Variations in the color of display pixels in a display such as temperature-induced color cast variations may be corrected by using a backlight unit having an array of light-emitting diodes of different colors. The array of light-emitting diodes may contain groups of diodes that are yellower or are otherwise colored differently than adjacent diodes. 
     An electrostatic discharge protection layer such as a layer of indium tin oxide on a color filter layer may be grounded to a housing using conductive tape. A radio-frequency shielding can may be shorted to the conductive tape using a layer of conductive foam. 
     Black display edge coatings and adhesive-based structures for mounting a display to a housing may be used to block stray light within a device such as stray light produced by a backlight unit for a display. 
     A camera module or other optical component may be aligned with a camera window region in a display. The camera window may be formed from a circular hole or other opening in an opaque masking layer that is formed in an inactive area of a display. The camera window may lie between inner and outer concentric rings of sealant. The sealant may be used to laterally confine liquid crystal material within the display. An outer ring of sealant may surround the inner ring of sealant. 
     The display may have a color filter layer and a thin-film transistor layer. The liquid crystal material may be formed in a layer between the color filter layer and the thin-film transistor layer. To prevent display layers such as the color filter layer and thin-film transistor layer from bowing in the region of the display between the inner and outer rings of sealant, support structures may be formed that connect the color filter layer and thin-film transistor layer between the inner and outer rings of sealant. The support structures may include a layer of clear adhesive in the vicinity of the camera window region. 
     Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative electronic device in accordance with an embodiment of the present invention. 
         FIG. 2  is a cross-sectional side view of a portion of a display mounted in an electronic device housing using an elastomeric gasket in accordance with an embodiment of the present invention. 
         FIG. 3  is a perspective view of an illustrative elastomeric gasket with an embedded stiffener in accordance with an embodiment of the present invention. 
         FIG. 4  is a perspective view of an illustrative portion of an elastomeric gasket in accordance with an embodiment of the present invention. 
         FIG. 5  is a cross-sectional side view of an illustrative elastomeric gasket and associated assembly tool showing how the gasket may be installed within a groove between a display and electronic device housing in accordance with an embodiment of the present invention. 
         FIG. 6  is a perspective view of an illustrative roller for installing an elastomeric gasket in an electronic device in accordance with an embodiment of the present invention. 
         FIG. 7  is a top view of a portion of an electronic device showing how an elastomeric gasket with an embedded stiffener may be installed within an electronic device housing around the periphery of the display in accordance with an embodiment of the present invention. 
         FIG. 8  is a cross-sectional side view of display structures and an associated polymer molding tool showing how an elastomeric gasket may be molded to the peripheral edges of the display structures in accordance with an embodiment of the present invention. 
         FIG. 9  is a perspective view of an electronic device housing with a recess that receives and surrounds a corner bracket in accordance with an embodiment of the present invention. 
         FIG. 10  is a cross-sectional side view of an electronic device having a housing that is in an unflexed condition in accordance with an embodiment of the present invention. 
         FIG. 11  is a cross-sectional side view of the electronic device of  FIG. 10  in a configuration in which the housing has been flexed in accordance with an embodiment of the present invention. 
         FIG. 12  is a cross-sectional side view of an illustrative electronic device having a gap-filling structure interposed between display backlight structures and housing structures in accordance with an embodiment of the present invention. 
         FIG. 13  is a cross-sectional side view of an adhesive and foam structure that may be used in attaching a display to a housing in accordance with an embodiment of the present invention. 
         FIG. 14  is a cross-sectional side view of a portion of an electronic device in which an adhesive-based structure such as the adhesive and foam structure of  FIG. 13  has been used in attaching a display to the electronic device in accordance with an embodiment of the present invention. 
         FIG. 15  is a diagram showing how a light-blocking layer may be formed on the ground edge of a display in accordance with an embodiment of the present invention. 
         FIG. 16  is a perspective view of an illustrative electronic device having a display that may be characterized by different operating temperatures in different regions in accordance with an embodiment of the present invention. 
         FIG. 17  is a cross-sectional side view of an illustrative display with backlight structures in accordance with an embodiment of the present invention. 
         FIG. 18  is a top view of display structures including a light guide plate with light scattering structures configured to help compensate for spatially varying color characteristics in the display structures in accordance with an embodiment of the present invention. 
         FIG. 19  is a cross-sectional side view of an illustrative display having a conductive tape structure for grounding an electrostatic discharge protection layer to a housing in accordance with an embodiment of the present invention. 
         FIG. 20  is a top view of an edge portion of a display that is being shorted to a housing structure using a conductive tape structure in accordance with an embodiment of the present invention. 
         FIG. 21  is a diagram showing how a display may have multiple concentric beads of sealant and may have a camera window in accordance with an embodiment of the present invention. 
         FIG. 22  is a cross-sectional side view of the display of  FIG. 21  showing how adhesive may be incorporated into the display in the vicinity of the camera window to provide structural support for layers in the display in accordance with an embodiment of the present invention. 
         FIG. 23  is a perspective view of an edge portion of a display showing how a printed circuit may have integral flexible printed circuit tails for attaching display driver circuitry to a thin-film-transistor layer in the display in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices such as notebook computers, tablet computers, cellular telephones, media players, televisions, and other electronic equipment may be provided with displays. 
     An illustrative electronic device such as a portable computer or other electronic equipment that has a display is shown in  FIG. 1 . As shown in  FIG. 1 , display  14  of device  10  may be mounted in housing  12 . Housing  12  may be formed from a single housing structure or may, as shown in  FIG. 1 , have multiple attached structures such as upper housing portion  12 A and lower housing portion  12 B. In this type of configuration, display  14  may be mounted in upper housing portion  12 A (as an example). 
     Housing  12  may be formed from a unibody construction in which some or all of housing  12  is formed form a unitary piece of material (e.g., metal, plastic, or fiber composite materials) or may be formed from multiple structures that have been mounted together using adhesive, fasteners, and other attachment mechanisms. For example, housing  12  may be formed from frame members and other internal supports to which external plates, housing sidewalls, bezel structures, and other structures are mounted. Hinge structures  18  may be used in attaching housings formed from multiple housing portions such as upper housing portion  12 A and lower housing portion  12 B. 
     Housing portion  12 A may be used to house display  14  and may sometimes be referred to as a display housing or lid. Display housing  12 A may be attached to housing portion  12 B (sometimes referred to as a main unit or base housing) using hinge structures  18 , so that display housing  12 A may rotate relative to main housing  12 B around hinge axis  16 . Device  10  may include ports for removable media, data ports, keys such as keyboard  20 , input devices such as track pad  24 , microphones, speakers, sensors, status indicators lights, and other components. If desired, device  10  may have a camera such as camera  26 . 
     Display  14  may have an active portion such as active central rectangular portion  28  and an inactive portion such as inactive portion  30 . Active portion  28  of display  14  may have a shape such as a rectangular shape bounded by line  32  of  FIG. 1 . Inactive portion  30  of display  14  may have a rectangular ring shape or other suitable shape and may form a border that runs along the periphery of display  14 . Display pixel array elements such as liquid crystal diode display pixels or other active display pixel structures may be used in portion  28  to present images to a user of device  10 . Inactive portion  30  is generally devoid of display pixels and does not participate in forming images for a user. To hide unsightly internal components from view, internal components in inactive portion  30  may be blocked from view by incorporating a black masking layer or other opaque masking layer into the peripheral portion of display  14 . 
     Display  14  may be a liquid crystal display, an electrophoretic display, an electrowetting display, a plasma display, an organic light-emitting diode display, or a display formed using other display technologies. Illustrative configurations for device  10  in which display  14  has been formed using liquid crystal display technologies are sometimes described herein as an example. This is, however, merely illustrative. Display  14  may, in general, be formed using any suitable type of display structures. 
     Device  10  may have components that are formed in inactive display region  30  such as camera  26 . Camera  26  may be mounted within display housing  12 A and may operate through a window (sometimes referred to as a camera window) in display  14 . The camera window may be created by forming a circular opening or an opening with another suitable shape in the layer of opaque masking material in region  30 . 
     Housings  12 A and  12 B may be formed from materials such as metal (as an example). To prevent undesired contact between the exposed inner faces of housings  12 A and  12 B when housing  12  has been placed in a closed-lid position, an elastomeric material (sometimes referred to as an elastomeric gasket) may be formed on a portion of housing  12  such as housing  12 A. An elastomeric gasket may, as an example, have a rectangular ring shape so that the gasket runs along line  32  of  FIG. 1  around the periphery of display  14 . The elastomeric gasket may protrude from housing  12 A so the elastomeric gasket forms a soft bumper structure that prevents housings  12 A and  12 B from directly rubbing against each other when housing  12 A has been placed in a closed position. 
     A cross-sectional side view of device  10  in the vicinity of a portion of an elastomeric gasket is shown in  FIG. 2 . As shown in  FIG. 2 , display  14  may include multiple display layers such as lower polarizer layer  34 , thin-film transistor layer  36 , color filter layer  40 , and upper polarizer layer  42 . A layer of liquid crystal material such as liquid crystal layer  38  may be interposed between thin-film transistor layer  36  and color filter layer  40 . Thin-film transistor layer  36  may have an array of electrodes and associated thin-film transistors. The electrodes and thin-film transistors may be used in controlling the application of electric fields to liquid crystal layer  38  to adjust the orientation of liquid crystals in layer  38 . In conjunction with upper and lower polarizers  34  and  42 , control of the electric fields in layer  38  may be used to adjust the transmission of the display pixels in display  14  and thereby present images on display  14  for a user of device  10 . Color filter layer  40  may include an array of color filter elements that provide display  14  with the ability to display color images. 
     Gasket  44  may be formed from a pliable (flexible) material such as an elastomeric polymer (e.g., silicone). Gasket  44  may have a recess such as recess  56  that is configured to receive edge  50  of display  14 . Recess  56  may be formed between protrusion  52  on the upper portion of gasket  44  and protruding portion  54  on the lower portion of gasket  44 . Protruding portions  52  and  54  and recess  56  may be configured so that gasket  44  has a C-shaped cross section for receiving edge  50 , as shown in  FIG. 2 . 
     The layers of display  14  may not all be aligned in the vicinity of edge  50 . For example, upper polarizer  42  may be recessed from edge  50 , so that an exposed strip of color filter layer  40  is formed such as exposed strip  48 . The presence of upper protruding portion  52  of gasket  44  may hide region  46  of display  14  from view, thereby blocking unsightly features such as exposed color filter strip  48  from view by a user of device  10 . 
     Housing  12 A may have a groove such as groove  58  that is configured to receive gasket  44 . Groove  58  may have an outer edge such as edge  60  and an inner edge such as edge  62 . As shown in the exploded perspective view of housing  12 A of  FIG. 3 , groove  58  may have a rectangular ring shape and may lie between inner groove edge  60  and outer edge  64  of display  14 . Along edge  68  of display  14 , gasket  44  may have an associated stiffener such as stiffener  66 . Stiffener  66  may, for example, be embedded within the elastomeric material that forms gasket  44 . Stiffener  66  may be formed from metal, fiber-based composites, or other stiff materials. As an example, stiffener  66  may be formed from a patterned sheet metal layer such as a layer of stainless steel or aluminum or other metal member configured to add stiffness to gasket  44  along edge  68  of display  14  and thereby facilitate assembly operations. Stiffener  66  may be attached to gasket  44  using adhesive or stiffener  66  (e.g., a patterned sheet metal member) may be incorporated into gasket  44  by molding elastomeric material for gasket  44  over stiffener  66  (e.g., using compression molding equipment or injection molding equipment). 
       FIG. 4  is a perspective view of a portion of a corner portion of gasket  44 . As shown in  FIG. 4 , gasket  44  may include notches such as notches  70  (e.g., in protruding lower edge portion  54 ). The presence of notches  70  in gasket  44  may help provide gasket  44  with flexibility during installation of gasket  44  in groove  58  and/or may help align gasket  44  with housing  12 A. 
       FIG. 5  is a cross-sectional side view of groove  58  showing how adhesive  72  may be placed on lower surface  74  of groove  58 . Adhesive  72  may be a pressure sensitive adhesive or other adhesive for attaching gasket  44  within groove  58 . During installation of gasket  44 , a user or computer-controlled equipment may press tool  78  against portion  82  of gasket  44  in directions such as direction  80 , thereby causing gasket  44  to rotate so that portion  54  of gasket  44  moves into groove  58  in direction  840  and so that edge  50  of display  14  is received within gasket recess  56  and so that surface  76  of gasket  44  lies on adhesive  72 . 
     A tool such as roller  84  of  FIG. 6  may also be used in installing gasket  44  within groove  58  between housing  12 A and display  14 . 
       FIG. 7  is a top view of housing  12 A showing how gasket  44  may be taped to housing  12 A along edge  68  using tape  86 . Following attachment of gasket  44  to housing  12 A using tape, assembly personnel or computer-controlled equipment may tuck gasket  44  into grove  58  (e.g., first tucking gasket  44  into corners  88 , second tucking gasket  44  into corner  90 , third tucking gasket  44  into corner  92 , and fourth tucking gasket  44  into groove  58  along edge  94 ). Following these gasket tucking operations, a roller such as roller  84  of  FIG. 6  may be used to roll the remainder of gasket  44  into groove  58  by rolling along edge  96  in direction  98 , along edge  94  in direction  100 , and along edge  102  in direction  104  (as an example). Other types of assembly operations may be used to install gasket  44  in groove  58  of housing  12 A, if desired. The use of corner and edge tucking operations (e.g., using a tool such as tool  78 ) followed by use of roller  84  is merely illustrative. 
     If desired, elastomeric gasket material may be attached to display  14  using molding equipment (e.g., compression molding tools, injection molding tools, etc.). As shown by display  14  in the upper portion of  FIG. 8 , for example, display  14  may initially be formed without any gasket material on edges  50 . Integral peripheral gasket  108  may then be formed by molding an elastomeric polymer over edges  50  using compression molding tool  106  or other plastic molding equipment, as shown in the lower portion of  FIG. 8 . Following attachment of gasket  108  to display  14 , display  14  may be installed in housing  12 A. 
     Housings  12 A and  12 B may be formed from a metal such as aluminum. To structurally reinforce the corners of housing  12  (e.g., housing  12 A), housing  12 A may be provided with corner brackets such as corner bracket  110  of  FIG. 9 . Corner brackets such as corner bracket  110  may be provided at each of the four corners of housing  12 A (as an example). Corner brackets such as corner bracket  110  may be formed from a material such as a stainless steel that is stronger than aluminum and which therefore adds structural strength to housing  12 A. The additional strength provided by corner brackets  110  may help device  10  avoid damage (e.g., to display  14 ) when a corner of device  10  strikes an external object during an unintentional drop event. Each corner bracket may be formed from a planar sheet metal member and may have opposing surfaces such as upper surface  111  and lower surface  113 , surrounded by peripheral edge  115 . 
     As shown in  FIG. 9 , housing  12 A may have a rear surface such as rear surface  121 . Raised edge portions such as inner rib  118  and outer rib  116  may surround a rectangular center portion of rear housing wall  121 . When fully assembled, display  14  may be cover inner rib  118  and outer rib  116 . Portions of inner rib  118  and outer rib  116  may be configured to form corner recesses such as corner recess  112 . Corner recess  112  may have a shape that is configured to receive corner bracket  110 . Adhesive-based attachment structures  120  or other suitable fastening mechanisms may be used to help retain corner bracket  110  within corner recess  112 , if desired. 
     Corner recess  112  may have a planar surface that is configured to mate with lower surface  113  of corner bracket  110 . Adhesive  120  may be interposed between surface  113  and the surface of recess  112 . The surface of recess  112  may be surrounded by inner recess edge  117 . The shape of edge  117  may be configured to match the shape of edge  115 , so that edge  117  may receive edge  115  and corner bracket  110 . When bracket  110  is mounted within housing  12 A, housing  12 A may surround bracket  110  on all sides (e.g., peripheral edge  115  of bracket  110  may be surrounded by portions of housing  12 A along edge  117 ). 
       FIG. 10  is a side view of device  10  showing how display  14  may be attached to display housing  12 A using an adhesive-based structure on inner rib  118  (e.g., a rectangular ring of adhesive-based materials). In the configuration of  FIG. 10 , device housing  12 A has not been subjected to a drop event and is therefore unflexed and planar. If dropped, device housing  12 A may flex, so that edge portions  122  of housing  12 A move in directions  124  away from display  14 . By locating adhesive-based attachment structures on inner ribs  118  but not on outer ribs  116  (i.e., so that outer ribs  116  are free of adhesive), downward force from ribs  116  pulling on display  14  can be eliminated, thereby reducing stress on display  14  and helping to avoid damage to display  14  in a drop event. 
       FIG. 12  is a cross-sectional side view of device  10  showing how display  14  may be provided with backlight illumination using backlight unit  126 . Backlight unit  126  may include light guide plate  148 , optical films  150 , and reflector  152 . When backlight unit  126  is operating, backlight  136  may travel in direction Z through display  14  so that user  138  may view backlit images on display  14 . Backlight unit  126  may be mounted on a ledge such as ledge  128  of housing  12 A. In region  140 , the shape of housing  12 A may be configured so that there is a gap G between lower (innermost) surface  132  of backlight unit  126  (i.e., the lower surface of reflector  152 ) and upper (innermost) surface  130  of the rear housing wall in housing  12 A. The size of gap G may be, for example, 1-10 mm, 1-5 mm, less than 4 mm, less than 2 mm, 0.5 to 3 mm, or other suitable size. 
     During use of device  10 , housing  12 A and display  14  may be subjected to drop events and other forces that may cause display  14  to bow downward in direction  142 . To prevent lower surface  132  of backlight unit  126  (i.e., the lower surface of reflector  152 ) from incurring damage by contacting inner surface  130  of display housing  12 A, a gap filling structure such as gap filing structure  134  may be interposed between backlight unit  126  and the rear housing wall formed by the portion of housing  12 A in region  140 . Gap filling structure  134  may have the shape of a rectangle (when viewed in direction  142 ) and may have a footprint that approximately matches that of backlight unit  126 . Examples of materials that may be used for forming gap filling structure  134  (sometimes referred to as a dome filler) are plastic, foam, structures that includes one or more layers of plastic and/or foam, plastic structures with cavities separated by ribs, etc. Gap filling structure  134  may have a lip such as lip  144  that rests on ledge  146  in housing  12 A or may be formed from a rectangular structure (e.g., a rectangular sheet of foam). 
       FIG. 13  is a cross-sectional side view of display  14  in device  10  in the vicinity of adhesive-based attachment structure  120 . As shown in  FIG. 13 , adhesive-based structure  120  may include multiple layers of material such as black adhesive layer  155 , black foam layer  156 , and black adhesive layer  158 . Due to the presence of foam layer  156 , structures  120  may become compressed during an impact event or other stress-producing event, thereby relieving stress from display  14 . By using opaque materials in forming adhesive-based attachment structures  120 , light from display (e.g., stray backlight from display backlight unit  126 ) may be blocked, thereby reducing light leakage in device  10 . 
     As shown in  FIG. 14 , for example, backlight unit  126  may emit stray light  160 . Adhesive-based attachment structure  120  may be formed from black layers of material or other opaque materials that block light  160  and thereby help reduce stray light in display  14  and device  10 . Some stray light may reach the edges of display  14  by traveling through display layers such as color filter layer  40  and thin-film transistor layer  36 . When this stray light reaches edge  50  of display  14 , there is a potential that surface roughness on edge  50  will cause the stray light to be scattered out of display edge  50  into locations that might be visible to a user of device  10 . To reduce the emission of stray light from edge  50 , edge  50  may be coated with an opaque material such as material  162 . Material  162  may coat edge  50  without coating adjacent exposed upper and lower surfaces of display (as shown in  FIG. 14 ) or may, if desired, cover parts of the nearby upper and lower surface of display  14 . Light-blocking coating  162  may be formed from ink (e.g., black ink) or other opaque materials. 
     An illustrative process for forming light-blocking structure  162  on edge  50  of display  14  is shown in  FIG. 15 . As shown in  FIG. 15 , an opaque masking layer such as masking layer  164  (e.g., a black masking layer) may be interposed between color filter layer  40  and thin-film transistor layer  36  near the edge of display  14  (e.g., in inactive region  30 ). As initially formed as part of the process of attaching layers  40  and  36  to each other, the outer edge of opaque masking layer  164  may not be aligned with the edges of color filter layer  40  and thin-film transistor layer  36 . Display layers such as layers  40  and  36  may be formed from transparent substrate materials such as plastic or glass. Using grinding equipment such as grinding tool  166 , the exposed edges of display  14  may be ground until exposed color filter edge  174 , exposed opaque masking layer edge  170 , and thin-film transistor edge  172  are aligned relative to lateral dimension  176  (which lies in the plane of display  14 ). Coating tool  176  may then be used to deposit an opaque coating on the edge of display  14  to form light-blocking structure  162 . In a rectangular display with four edges, light-blocking coatings such as light-blocking structure  162  of  FIG. 15  may be formed on all four edges of display  14  or on a subset of the four edges of display  14 . 
     Housing  12 B may contain components that generate heat such as a microprocessor, video chips, communications circuits, memory, application-specific integrated circuits, power supply components, and other circuitry. This circuitry may be cooled using circulated air. As an example, housing  12 B may contain fan-based cooling structures such as structures  182  that draw cool air  178  into housing  12 B from the surrounding environment and that expel corresponding heated air  184 . As shown in  FIG. 16 , heated air  184  may tend to heat regions  186  of display  14  more than other regions of display  14 . This may tend to affect the color performance of display  14 . In particular, in the absence of corrective action, the display pixels and therefore the image content on display  14  in heated areas such as heated areas  186  may have a bluish color cast relative other areas of display  14 . 
     To compensate for the excessively blue color of the display pixels in regions such as regions  186  that are experiencing elevated temperatures during operation of device  10 , display  14  may be backlit using an array of light-emitting diodes of different colors such as yellowish light-emitting diodes and white light-emitting diodes. The backlight unit in display  14  may also be provided with a light guide plate scattering pattern that helps scatter backlight out of display  14  in a pattern that directs an enhanced amount of yellowish light through regions  186  and thereby compensates for the bluish color in regions  186 . 
     A cross-sectional side view of a backlight arrangement of the type that may be used in display  14  is shown in  FIG. 17 . As shown in  FIG. 17 , light  188  may be generated by a light source such as light source  190 . Light  188  may be launched into edge  192  of light guide plate  148 . Light guide plate  148  may be formed from transparent plastic (as an example). Light  188  may be distributed throughout light guide plate  148  in the X-Y plane due to the principal of total internal reflection. Light that scatters from features such as light-scattering features  154  may propagate upwards in direction Z as backlight  136 . Backlight  136  may pass through display  14  and may help user  194  view images on display  14 . A reflective layer such as reflector  152  may reflect light that has scattered downwards back in upwards direction Z, thereby enhancing backlight efficiency. Optical films  150 , which may be interposed between light guide plate  148  and display  14  may include a diffusing layer and light-collimating layer (as examples). 
     Light source  190  may be formed from an array of light-emitting diodes mounted on a flexible printed circuit or other substrate. The array of light-emitting diodes may extend along edge  192  of light guide plate  148  in dimension X. To help compensate display  14  for temperature-induced color variations or other location-based color variations, the color of the light-emitting diodes may be varied as a function of dimension X. The light scattering efficiency of light-scattering structures  154  may also be varied as a function of location in display  14  (i.e., dimensions X and Y). Light-scattering structures  154  may, as an example, be formed from pits in the surface of light guide plate  148  (e.g., laser-etched pits having a diameter of about 10-16 microns). To adjust the light scattering efficiency of light-scattering structures  154 , the density of light-scattering structures  154  (i.e., the number of structures  154  per unit area), the size of light-scattering structures  154 , and/or the shape of light-scattering structures  154  may be varied. 
       FIG. 18  is a top view of display  14  showing how light-emitting diodes  190  may be organized in a line parallel to edge  192  of light guide plate  148 . Light-emitting diodes  190  may be mounted on a substrate such as flexible printed circuit  196  (e.g., a sheet of polyimide or a layer of other flexible polymer). Light-emitting diodes  190  may emit light  188  that is coupled into edge  192  of light guide plate  148 . When traveling through light guide plate  148 , light  188  will be scattered in dimension Z by light-scattering structures  154  to serve as backlight for display  14 . 
     As shown in  FIG. 18 , different light-emitting diodes  190  may be provided with different colors. In particular the light-emitting diodes labeled “W” may emit light that is white, whereas the groups of light-emitting diodes labeled “Y” may emit light that is more yellow than the light-emitting diodes labeled “W”. The white emitting diodes labeled “W” (i.e., the light-emitting diodes that are adjacent to the groups of yellow light-emitting diodes) may be aligned (in dimension X) with portions (i.e., vertically extending regions) of display  14  that are not elevated in temperature and that therefore operate satisfactorily with normal (e.g., white-light) illumination. 
     In regions  186 , the operating temperature of display  14  is elevated, which causes the display pixels to tend to exhibit light with a bluish color. To compensate for the overly-blue tendencies of the display pixels in regions  186 , light-emitting diodes  190  that are aligned (in dimension X) with elevated temperature regions  186  (i.e., the “Y” light emitting diodes of  FIG. 18 ) may emit light that is yellowish relative to the light emitted by the white light-emitting diodes. The presence of yellowish light  188  in regions  186  will tend to counteract the inherent bluish cast of the display pixels in regions  186  due to the elevated temperature in regions  186 . 
     There is generally a decrease in light intensity for light  188  as a function of distance Y into light guide plate  148 . To counteract this light intensity drop-off, light-scattering structures  154  may be provided with a light-scattering efficiency that increases with increases in dimension Y. This increase in light-scattering efficiency as a function of increasing Y value is illustrated by the enhanced density of light-scattering structures  154  with increases in dimension Y in  FIG. 18 . Within regions  186 , extra yellow light may be scattered towards the viewer to compensate for the bluish color cast of the display pixels in regions  186  by providing light-scattering structures  154 ′ in regions  186  with more light scattering efficiency than comparable light-scattering structures  154  (i.e., light-scattering structures  154  in laterally adjacent portions of display  14 ). With this configuration, more efficiency is provided to light-scattering structures  154 ′ in regions  186  than structures  154  that are located at the same location in dimension Y but that are offset in dimension X so as to fall outside of regions  186 . As a result of using a pattern of light-scattering structures that exhibit localized increases in light-scattering efficiency, luminance (light intensity) may not be completely uniform on display  14 . Nevertheless, because the human eye is more sensitive to color variations than luminance variations, the use of compensating light-emitting diode colors and light-scattering structures  154 ′ with locally enhanced light-scattering efficiencies tends to improve perceived display performance. 
     Display  14  may include a conductive layer such as a layer of indium tin oxide (ITO) for providing protection from damage due to electrostatic discharge events. When a finger of a user or other external object comes into contact with the outer surface of display  14  such as outer surface  198  of display  14  of  FIG. 19 , there is a risk for undesired static charge accumulation that could disrupt the electric fields within liquid crystal layer  38 . Conductive layer  200  (e.g., an indium tin oxide layer or other transparent conductive electrostatic discharge protection layer) may be used to prevent events of this type from disrupting display operation. As shown in  FIG. 19 , conductive layer  200  may be interposed between upper polarizer layer  198  and color filter layer  40 . 
     In edge region  222 , a strip of conductive layer  200  may be exposed (i.e., not covered with polarizer layer  198 ). This allows a conductive path to be formed between conductive layer  200  and a source of ground such as metal housing structure  12 A. Conductive layer  204  may be, for example, a layer of metal tape. Conductive adhesive  202  may be used to attach conductive tape  204  to conductive layer  200  in region  222 . Conductive adhesive  206  may be used to attach portion  220  of conductive tape structure  204  to housing  12 A. Housing  12 A may, if desired, be formed from a metal that has an insulating coating such as aluminum covered with an insulating coating of aluminum oxide. As shown in  FIG. 19 , laser etching or machining operations may be used to create uncoated region  224  on housing  12 A to ensure that oxide or other insulating materials do not degrade the quality of the electrical connection formed between portion  220  of structure  204  and housing  12 A. If desired, fasteners, welds, connectors, or other electrical attachment mechanisms may be used in forming electrical connections between the ends of conductive tape structure  204  and conductive structure  200  and housing  12 A. The use of conductive adhesive in forming these connections in the configuration of  FIG. 19  is merely illustrative. 
     Thin-film transistor layer  36  may have a portion such as thin-film transistor ledge  210  that is uncovered by color filter layer  40 . Display driver integrated circuits such as circuit  208  may be mounted on ledge  210 . Ancillary display circuits such as display circuit  214  may be mounted on other substrates such as printed circuit  212 . Printed circuit  212  may be a rigid printed circuit board (e.g., a layer of fiberglass-filled epoxy) or may be a flexible printed circuit (e.g., a printed circuit formed from a flexible sheet of polyimide or other flexible polymer). Radio-frequency electromagnetic signal shielding structures such as metal shielding can  216  may be grounded to ground traces on printed circuit  212  and may be used to cover and shield circuitry  214 . Conductive foam  218  may be interposed between shield can  216  and conductive tape structure  204 . As shown in  FIG. 19 , can  216  may be shorted to portion  220  of structure  205  using conductive foam  218 . 
     A top view of conductive tape structure  204  of  FIG. 19  is shown in  FIG. 20 . 
       FIG. 21  is a front view of display  14  showing how rings of sealant may be used in sealing liquid crystal material  38  within display  14 . As shown in  FIG. 21 , a bead of sealant such as sealant bead  226  may run around the periphery of display  14  between color filter layer  40  and thin-film transistor layer  36 . The bead of sealant may have a cross-over region such as region  240 , so that a single line of sealant may form inner and outer concentric rings of sealant such as outer ring  228  and inner ring  230 . By using sealant  226 , liquid crystal material  38  may be laterally sealed within the cavity formed between color filter layer  40  and thin-film transistor layer  36 . The layer of liquid crystal material that is interposed between color filter layer  40  and thin-film transistor layer  36  may have a thickness of about 3-5 microns, about 1-10 microns, more than 3 microns, less than 5 microns, or other suitable thickness. 
     Liquid crystal material  38  may be confined within the rectangular region defined by sealant structures  226  (i.e., inner sealant ring  230  may run along the periphery of rectangular liquid crystal material layer  38  in active display region  28 ). A gap such as gap GP may be formed between outer ring  228  and inner ring  230 . Gap GP may be free of active display pixels (i.e., gap GP may lie in inactive display region  30 ) and may or may not contain liquid crystal material. 
     To prevent display layers such as color filter layer  40  and thin-film transistor layer  36  bowing in gap region GP and thereby forming undesired Newton&#39;s rings that may be visible to a user, a support structure such as a structure formed from a supportive layer of material may be formed in regions such as region  234  (and if desired, in other portions of gap GP running around the periphery of display  14 ). The supportive layer of material in region  234  (and, if desired, other portions of gap GP between rings  228  and  230 ) may be formed from a layer of adhesive. 
     Spacers  232  may have a defined height in dimension Z (e.g., 3-5 microns or other suitable height). When color filter layer  40  and thin-film transistor layer  36  are attached to each other, spacers  232  (which may also be formed in the array of display pixels for display  14  within liquid crystal material  38 ) may ensure that the spacing between layer  40  and layer  36  has a well-defined thickness during the introduction of the layer of adhesive in liquid form. Spacers  232  may be formed from columns of polymer (e.g., columns of polyimide patterned using photolithography). 
     The adhesive may be a clear ultraviolet-light-curable liquid adhesive that flows between layers  40  and  36  around spacers  232 . The liquid adhesive may be cured by applying ultraviolet light through thin-film transistor layer  36 . Once cured, the clear liquid adhesive may become rigid and may fill the space between layers  40  and  36  with a solid support structure that prevents layers  40  and  36  from bowing relative to each other. Use of a clear material for the adhesive in region  234  may allow light for camera  26  or other optical components to pass through the adhesive. 
     A cross-sectional side view of display  14  in the vicinity of camera  26  is shown in  FIG. 22 . The cross-sectional side view of  FIG. 22  is taken along line  236  and is viewed in direction  238  of  FIG. 21 . As shown in  FIG. 22 , color filter layer  40  and thin-film transistor layer  36  may be separated by a thickness T (e.g., a thickness of 3-5 microns, 1-10 microns, more than 3 microns, less than 5 microns, or other suitable thickness). Liquid crystal material  38  may be interposed between color filter layer  40  and thin-film transistor layer  36  in active area  28 . Sealant may prevent liquid crystal material  38  from escaping from the edges of display  14  in dimensions X and Y. 
     An opaque masking layer such as opaque masking layer  164  may be formed on the underside of color filter layer  40  in inactive region  30 . Opaque masking layer  164  may block internal display structures from view by a user. For example, opaque masking layer  164  may block sealant rings  228  and  230  from view. 
     Camera  26  may include a camera module such as camera module  241  (sometimes referred to as a camera). Camera module  241  may have a digital image sensor such as image sensor  244  and lens structures  242 . Lens structures  242  and image sensor  244  may be aligned with opening  248  in opaque masking layer  164 , so that image light  246  for digital images may be captured by camera module  241 . Opening  248  may sometimes be referred to as a camera window. The shape of opening  248  may be, for example, a circle that is aligned with a circular lens in lens structures  242 . 
     Sealant rings  228  and  230  may be separated by a gap such as gap GP. To support color filter layer  40  and thin-film transistor layer  36  within gap GP, adhesive  250  may be interposed between color filter layer  40  and thin-film transistor layer  36  within gap GP. Adhesive  250  may be a clear adhesive that allows light  246  associated with an image to pass through gap GP to camera module  241 . If desired, a keep-out zone (e.g., a circular region overlapping lens  242 ) may be used to prevent adhesive  250  from filling the portion of gap GP that lies directly above lens  242 . In configurations of the type shown in  FIG. 22  in which adhesive  250  fills substantially all of gap GP in the vicinity of camera module  241  (e.g., when adhesive  250  fills gap GP at least within region  234  of  FIG. 21 ), adhesive  250  may serve as an index-matching structure that helps to reduce reflections from the surface of layers  40  and  36  and thereby improve camera performance. 
     As shown in the perspective view of display  14  of  FIG. 23 , display  14  may be controlled using display driver integrated circuits such as integrated circuits  254  on thin-film transistor ledge  210  and integrated circuits  256  (e.g., timing circuits) on printed circuit structure  252 . Printed circuit structure  252  may be formed from a rigid printed circuit substrate (e.g., a fiberglass-filled epoxy substrate or other rigid dielectric substrate). Integral flexible printed circuit tail  258  may protrude from rigid printed circuit substrate  252 . With this type of “rigid flex” board, components  256  may be mounted on a rigid printed circuit substrate structure, whereas conductive traces on flexible printed circuit portion  258  such as traces  260  may be used in forming electrical connections between integrated circuits  256  and integrated circuits  254  on thin-film transistor ledge  210 . Conductive adhesive or other suitable conductive attachment structures may be used to form electrical connections between the traces on flexible printed circuit tail  258  and corresponding traces on the surface of thin-film transistor layer  36 . Traces on the surface of thin-film transistor layer  36  may be used to interconnect traces  260  and circuitry  256 . 
     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: 20150629
Publication Date: 20180605
Grant Date: 20180605
Priority Date: 20120608
Inventors: MATHEW, DINESH C.
POSNER, BRYAN W.
HENDREN, KEITH J.
GARELLI, ADAM T.
GIDDINGS, JOSS NATHAN
WILSON, JR., THOMAS W.
YIN, VICTOR H.
QI, JUN
JIAO, MEIZI
WANG, PAUL XIAOPENG
Assignee: APPLE INC
CPC Classifications: [{"code": "H05K5/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F2200/1612", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1616", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/0266", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04M1/185", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1601", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1637", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/1601", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K5/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/185", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04M1/0266", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F2200/1612", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1601", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1616", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1637", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F2200/1612", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04M1/185", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04M1/0266", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 49715188