PATENT DOCUMENT

Publication Number: US-9164309-B2
Application Number: US-201213481560-A
Country: US
Kind Code: B2

Title: Display with broadband antireflection film

Abstract:
Display layers in an electronic device may be used to generate images. The display layers may include liquid crystal display layers such as upper and lower polarizers and a layer of liquid crystal material. A display cover layer may be mounted in a housing adhesive. A touch sensor layer may be mounted under the display cover layer. An air gap may separate the upper polarizer from the touch sensor layer and display cover layer. Antireflection coatings may be formed on the lower surface of the display cover layer or touch sensor layer and may be formed on the upper surface of the upper polarizer. The antireflection coatings may include coatings formed from a polymer hard coat covered with a polymer layer having a different index of refraction and may include broadband antireflection coating material formed from textured polymer or other structure exhibiting a continuously varying index of refraction.

Claims:
What is claimed is: 
     
       1. Display structures, comprising:
 a touch sensor layer with first and second opposing sides; 
 a first patterned transparent electrode on the first side of the touch sensor layer; 
 a second patterned transparent electrode on the second side of the touch sensor layer; 
 a broadband antireflection layer, wherein the broadband antireflection layer comprises a textured surface that creates a continuously varying refractive index in a direction from the uppermost surface to the lowermost surface; and 
 display layers that generate an image, wherein the display structures comprise an antireflection layer, wherein the antireflection layer comprises first and second layers, and wherein the second layer includes hollow structures that are completely surrounded by the second layer, wherein the first layer comprises a polymer layer having a thickness of 5 to 7 microns, wherein the antireflection layer is in direct contact with the first patterned electrode. 
 
     
     
       2. The display structures defined in  claim 1  wherein the first and second layers have respective first and second indices of refraction. 
     
     
       3. The display structures defined in  claim 2  wherein the second layer comprises a polymer layer with a thickness of 20 to 500 nm. 
     
     
       4. The display structures defined in  claim 1  wherein the display layers include a liquid crystal layer. 
     
     
       5. The display structures defined in  claim 1  further comprising a display cover layer to which the touch sensor layer is attached. 
     
     
       6. An electronic device, comprising:
 a housing; 
 a display cover layer; 
 a touch sensor substrate with a patterned transparent electrode on a lower surface of the touch sensor substrate; 
 display layers configured to generate an image, wherein the display layers include a polarizer; 
 a broadband antireflection layer having upper and lower surfaces and formed from a bulk material having a first index of refraction, wherein the broadband antireflection layer has a refractive index that varies continuously from the first index of refraction at the lower surface to a second index of refraction at the upper surface; 
 an antireflection layer in direct contact with the polarizer, wherein the antireflection layer and the broadband antireflection layer are separated by a gap; and 
 a layer of pressure sensitive adhesive with which the broadband antireflection layer is mounted within the electronic device, wherein the layer of pressure sensitive adhesive is interposed between and in direct contact with the broadband antireflection layer and the patterned transparent electrode. 
 
     
     
       7. The electronic device defined in  claim 6  wherein the antireflection layer on the polarizer comprises at least first and second polymer layers with different respective first and second indices of refraction. 
     
     
       8. The electronic device defined in  claim 6  wherein the broadband antireflection layer comprises a textured surface that creates a continuously varying refractive index. 
     
     
       9. The electronic device defined in  claim 8  further comprising adhesive that attaches the display cover layer to the housing. 
     
     
       10. The electronic device defined in  claim 8  further comprising:
 an additional polarizer; and 
 a liquid crystal layer located between the polarizer and the additional polarizer. 
 
     
     
       11. The electronic device defined in  claim 6  wherein the second index of refraction comprises an index of refraction of air. 
     
     
       12. The display structures defined in  claim 1 , wherein the display structures comprise a polarizer layer and wherein the antireflection layer is mounted on the polarizer layer. 
     
     
       13. The display structures defined in  claim 1 , wherein the display layers and the broadband antireflection layer are separated by an air gap. 
     
     
       14. The display structures defined in  claim 1 , wherein the hollow structures comprise silica beads. 
     
     
       15. The display structures defined in  claim 3 , wherein the first index of refraction is about 1.5 and the second index of refraction is between 1.2 and 1.3. 
     
     
       16. The display structures defined in  claim 1 , wherein the broadband antireflection layer is attached to a polarizer with pressure sensitive adhesive. 
     
     
       17. The display structures defined in  claim 1 , wherein the antireflection layer is in direct contact with the first side of the touch sensor layer. 
     
     
       18. The display structures defined in  claim 17 , wherein the first patterned transparent electrode has first and second opposing sides connected by third and fourth opposing sides, wherein the first side of the first patterned transparent electrode is in direct contact with the first side of the touch sensor layer, and wherein the second, third, and fourth sides of the first patterned transparent electrode are in direct contact with the antireflection layer.

Description:
BACKGROUND 
     This relates generally to electronic devices, and, more particularly, to electronic devices with displays. 
     Electronic devices such as computers, cellular telephones, televisions, and other equipment often have displays. For example, an electronic device may have a liquid crystal display that includes upper and lower polarizer layers, a thin-film transistor layer and a color filter layer that are interposed between the upper and lower polarizer layers, and a layer of liquid crystal material interposed between the thin-film transistor layer and color filter layer. 
     To prevent damage to the display, a protective layer of cover glass may be provided. In displays with touch sensors, a touch sensor panel may be attached to the underside of the display cover glass. 
     To reduce unwanted reflections within a display, layers of material in the display such as the lower surface of the touch sensor panel and the upper surface of the upper polarizer are sometime coated with antireflection coatings. These coatings are formed using a wet coating process and are therefore referred to as wet antireflection coatings. During formation of a wet antireflection coating on a substrate, liquid coating materials are deposited on a surface of a substrate. By drying the liquid coating materials, clear antireflection films can be formed. 
     Some displays use a full lamination process in which the touch sensor panel is laminated to underlying layers such as the upper polarizer layer using adhesive. Fully laminated displays may exhibit satisfactory display performance, but can be difficult or impossible to rework in the event that a touch sensor component requires replacement during manufacturing. 
     To allow a display to be reworked, the touch sensor panel in a display may be separated from the upper polarizer by an air gap. During manufacturing, devices that contain defective touch sensor parts can be reworked. Wet antireflection layers may be formed on the lower surface of the touch sensor panel and on the upper surface of the upper polarizer on opposing sides of the air gap. If care is not taken, however, pressure from a user&#39;s finger on the cover glass on the front of a display can lead to undesirable visible artifacts such as Newton&#39;s rings. If, for example, a user presses inwardly on the cover glass on a display, the cover glass may flex inwardly towards the upper polarizer. With sufficient pressure, the inner surface of the cover glass or the inner surface of a touch panel mounted on the cover glass may bridge the air gap and come into contact with the upper surface of the polarizer, leading to the production of unsightly Newton&#39;s rings on the display. 
     It would therefore be desirable to be able to provide improved displays for electronic devices. 
     SUMMARY 
     An electronic device may be provided with a display. The display may have display layers that contain an array of display pixels for displaying images for a user. 
     The display layers may include liquid crystal display layers such as upper and lower polarizers, a thin-film transistor layer containing an array of pixel electrodes and associated thin-film transistor circuitry, a color filter layer, and a layer of liquid crystal material. 
     The electronic device may have a housing. A display cover layer may be mounted in the housing adhesive. A touch sensor layer may be mounted under the display cover layer. 
     An air gap may separate the upper polarizer from the touch sensor layer and display cover layer. Antireflection coatings may be formed on the lower surface of the display cover layer or touch sensor layer and may be formed on the upper surface of the upper polarizer. The surfaces of the antireflection coatings may face one another across the air gap. 
     The antireflection coatings may include wet antireflection coatings such as coatings formed from a polymer hard coat covered with a polymer layer having a different index of refraction. The antireflection coatings may also include broadband antireflection coating films. A broadband antireflection film may be formed from textured polymer or other structure exhibiting a continuously varying index of refraction as a function of distance through the film. A device may contain a pair of opposing broadband antireflection coatings or may contain an antireflection layer such as a wet antireflection layer and a broadband antireflection layer. 
     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 front perspective view of an illustrative electronic device of the type that may be provided with display structures in accordance with an embodiment of the present invention. 
         FIG. 2  is a cross-sectional side view of an electronic device with display structures in accordance with an embodiment of the present invention. 
         FIG. 3  is a cross-sectional side view of a substrate with a wet antireflection coating that contains hollow silica spheres to adjust the index of refraction of one of the layers in the antireflection coating in accordance with an embodiment of the present invention. 
         FIG. 4  is a cross-sectional side view of a substrate with a wet antireflection coating that contains a lower hard coat layer and an upper fluorinated polymer layer in accordance with an embodiment of the present invention. 
         FIG. 5  is a cross-sectional side view of a substrate with a broadband antireflection film having a surface texture configured to produce a continuously varying index of refraction at different depths into the film in accordance with an embodiment of the present invention. 
         FIG. 6  is a cross-sectional side view of a substrate such as a display cover layer that has been coated with a layer of broadband antireflection film in accordance with an embodiment of the present invention. 
         FIG. 7  is a cross-sectional side view of display structures having two opposing layers of broadband antireflection film in accordance with an embodiment of the present invention. 
         FIG. 8  is a cross-sectional side view of display structures having an upper wet antireflection coating and a lower broadband antireflection coating in accordance with an embodiment of the present invention. 
         FIG. 9  is a cross-sectional side view of display structures having a lower wet antireflection coating and an upper broadband antireflection coating in accordance with an embodiment of the present invention. 
         FIG. 10  is a diagram showing equipment and techniques of the type that may be used in forming display structures with antireflection layers in accordance with the present invention. 
         FIG. 11  is a cross-sectional side view of illustrative display structures showing which portions of the display structures may be autoclaved together in accordance with an embodiment of the present invention. 
         FIG. 12  is a cross-sectional side view of display structures showing how different portions of the display structures may be formed using separate autoclave operations in accordance with an embodiment of the present invention. 
         FIG. 13  is a flow chart of illustrative steps involved in forming display structures in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices may be provided with broadband antireflection films. A broadband film may have a surface texture or other configuration that gives rise to a continuously varying index of refraction as a function of distance perpendicular to the surface of the film. At the outermost surface of the film, the film may exhibit an index of refraction equal to that of air, providing a smooth interface (i.e., minimal index of refraction discontinuity) with an air gap in a display. Broadband antireflection films of this type, which may sometimes be referred to as moth-eye films, may be used to decrease unwanted reflections in a display. The broadband films may also be used to prevent or at least reduce the formation of undesired visual artifacts such as Newton&#39;s rings. Multiple broadband films may be used or a broadband film may be used in conjunction with a wet antireflection layer. 
     An illustrative electronic device in which broadband antireflection film may be used is shown in  FIG. 1 . Device  10  may include one or more layers of antireflection film. For example, device  10  may have one or more layers of broadband antireflection film having an index of refraction that varies as a function of distance perpendicular to the surface of the film. 
     As shown in  FIG. 1 , device  10  may have a display such as display  50 . Display  50  may be mounted on a front (top) surface of device  10  or may be mounted elsewhere in device  10 . Device  10  may have a housing such as housing  12 . Housing  12  may have curved portions that form the edges of device  10  and a relatively planar portion that forms the rear surface of device  10  (as an example). Housing  12  may also have other shapes, if desired. 
     Housing  12  may be formed from conductive materials such as metal (e.g., aluminum, stainless steel, etc.), carbon-fiber composite material or other fiber-based composites, glass, ceramic, plastic, other materials, or combinations of two or more of these materials. 
     Device  10  may have user input-output devices such as button  59 . Display  50  may be a touch screen display that is used in gathering user touch input or may be a display that is insensitive to touch. The surface of display  50  may be covered using a dielectric display cover layer such as a planar cover glass member or a clear layer of plastic. The central portion of display  50  (shown as region  56  in  FIG. 1 ) may be an active region containing display pixels to display images for a user. The active region may also contain touch sensor components that are sensitive to touch input. The peripheral portion of display  50  such as region  54  may be an inactive region that is free from touch sensor components and that does not display images. If desired, a borderless or nearly borderless design may be used for device  10 . The example of  FIG. 1  is merely illustrative. 
     A cross-sectional side view of device  10  taken along line  14  of  FIG. 1  and viewed in direction  16  is shown in  FIG. 2  (not to scale). As shown in  FIG. 2 , device  10  may include a display cover layer such as display cover layer  60 . Display cover layer  60  may be attached to ledge portion  62  of housing wall  12  using adhesive  64 . To decouple display cover layer from potentially heavy display components in housing  12  and thereby improve the reliability of adhesive  64  in holding display cover layer  60  in place during a drop event or other unexpected impact to device  10 , it may be desirable to form an air gap such as air gap  66  among the layers of material that make up display  50 . The thickness D of air gap  66  may be, for example, 0.2 mm, less than 0.3 mm, in the range of 0.1 to 0.3 mm, etc. By incorporating air gap  66  into device  10 , display cover layer  60  need not carry the weight associated with display components such as a color filter layer, thin-film transistor layer, and other such display layers. 
     Backlight for display  50  may be provided by a backlight unit such as backlight unit  68 . Backlight unit  68  may include a light source such as an array of light-emitting diodes or a lamp. Light from the light source may be launched into a light guide plate formed from a planar rectangular sheet of plastic. The light that is launched into the light guide plate may travel laterally (in the X-Y plane of  FIG. 2 ) due to total internal reflection. To improve backlight efficiency, a reflector such as a white sheet of plastic may be located below the light guide plate. Light that leaks vertically upwards in direction Z from the light guide plate may serve as backlight for display  14 . 
     Display  50  may include display layers  70 . In general, display  50  may be a liquid crystal display, a plasma display, an electrowetting display, an electrophoretic display, a light-emitting diode display such as an organic light-emitting diode display, or other suitable display. Configurations in which display  50  has been formed using liquid crystal display technology are sometimes described as an example. This is, however, merely illustrative. Any suitable type of display technology may be used in forming display  50 , if desired. 
     Display layers  70  may be, for example, liquid crystal display layers. Layers  70  may include a lower polarizer such as polarizer layer  72  and an upper polarizer such as upper polarizer layer  74 . Liquid crystal display layers may be sandwiched between lower polarizer layer  72  and upper polarizer layer  74 . Liquid crystal display layers  70  may include thin-film transistor layer  76  and color filter layer  82 . Thin-film transistor layer  76  may be formed from a transparent substrate material such as a layer of glass or plastic. Thin-film transistor circuitry  78  may be used to form an array of display pixels having electrodes. During operation of display  50 , signals from a display driver circuit may be used to control the operation of the display pixels in the array by modulating the electric field that is imposed on liquid crystal layer  80  by the electrodes. In this way, the display driver circuit may display images on display  50  for a user of device  10 . Color filter layer  82  may include an array of color filter elements (e.g., red, green, and blue elements) for providing display  50  with the ability to display color images. 
     Device  10  may be provided with an optional touch sensor array such as touch sensor array  88 . Touch sensor array  88  may be mounted on the lower (innermost) surface of display cover layer  60  using adhesive  96  (e.g., optically clear adhesive). Touch sensor array  88  may include a touch sensor substrate such as substrate  90 . Substrate  90  may be formed from a layer of clear glass, clear plastic, or other transparent dielectric. Patterned transparent electrodes such as electrodes  94  and  92  may be formed on the upper and lower surfaces of substrate  90 , respectively. Any suitable pattern may be used for electrodes  94  and  92  (e.g., diagonally interconnected checkerboard patterns, patterns with vertical and horizontal strips of electrode material, etc.). With one illustrative configuration, electrodes  94  may be formed from strips of conductive material that run parallel to the Y axis of  FIG. 2  and electrodes  92  may be formed from strips of conductive material that run parallel to the X axis of  FIG. 2 . Electrodes  92  and  94  may be formed from a transparent conductive material such as indium tin oxide and may be used in forming capacitive touch sensor electrodes for a capacitive touch sensor array. 
     Antireflection layers such as layers  98  and  100  may be formed on the display layer surfaces that face gap  66 . For example, antireflection layer  98  may be formed on the lower surface of touch sensor array  88 . A layer of pressure sensitive adhesive may be used to attach antireflection coating  98  to touch sensor array  88 . In configurations in which touch sensor array  88  is not present in device  10  (e.g., because display  50  is being implemented using a touch insensitive design), antireflection coating  98  may be formed on the innermost surface of display cover layer  60  instead of the innermost surface of touch sensor array  88 . 
     Antireflection layer  100  may be formed on the upper (outermost) surface of display layers  70 . For example, in a liquid crystal display arrangement, antireflection coating  100  may be formed on the outermost surface of upper polarizer layer  74  (e.g., using a layer of pressure sensitive adhesive). 
       FIG. 3  shows an illustrative antireflection coating arrangement that may be used for forming antireflection coatings such as coating  98  and/or coating  100 . As shown in  FIG. 3 , antireflection coating  102  may be formed on a substrate such as substrate  108 . Coating  102  may be, for example, coating  98  or coating  100  of  FIG. 2 . Substrate  108  may be upper polarizer  74  in display layers  70  or may be touch sensor array  88  or display cover layer  60 . 
     Antireflection coating  102  may include a first layer such as layer  106  and a second layer such as layer  104 . Layer  106  may be formed form a transparent material having an index of refraction of about 1.5 (e.g., a photoacrylic polymer) and may have a thickness T 2  of about 5-7 microns, a thickness of less than 15 microns, a thickness of 1-15 microns, or a thickness of more than 3 microns (as examples). Layer  106  may sometimes be referred to as a hard coat. 
     Layer  104  may be formed from a polymer that contains hollow silica beads  110  (e.g., hollow spheres having a diameter of about 30 nm, 10-40 nm, less than 100 nm, or other suitable size). The presence of hollow silica beads in polymer layer  104  may configure layer  104  so that layer  104  exhibits an index of refraction of about 1.2 to 1.3 (i.e., an index that is different from the index of layer  106 ). The thickness T 1  of layer  104  may be, for example, about 100 nm (e.g., a thickness of 20-500 nm or other suitable thickness value). By proper selection of the indices of refraction and thicknesses of layers  104  and  106 , coating  102  may be configured to serve as an antireflection coating at frequencies of interest (e.g., at visible light wavelengths). Coating  102  of  FIG. 3  may sometimes be referred to as a wet antireflection coating or wet antireflection layer. 
     Another illustrative configuration for a wet antireflection coating for display  50  is shown in  FIG. 5 . In the configuration of  FIG. 5 , coating  106  may be, for example, a polymer layer such as a hard coat layer with a thickness of about 5-7 microns, 1-15 microns, or other suitable thickness values (as examples) and an index of refraction of about 1.5. Coating  104 ′ may be formed from a layer of fluorinated polymer. Coating  104 ′ may exhibit an index of refraction of about 1.3. The thickness T 1  of coating layer  104 ′ may be about 100 nm, 20-500 nm, or other values (as examples). By selecting appropriate indices of refraction and thicknesses for layers  106  and  104 ′ in coating  102 , coating  102  may be configured to serve as an antireflection coating. 
     An antireflection layer with a gradually changing index of refraction as a function of vertical dimension Z may be used as an antireflection coating in display  50 . This type of antireflection layer may exhibit a relatively broadband antireflection characteristic and may therefore sometimes be referred to as a broadband antireflection layer. 
     An illustrative broadband antireflection layer is shown in  FIG. 5 . As shown in  FIG. 5 , broadband antireflection layer  112  may include protrusions such as protrusions  114  that are separated from each other by interposed valleys  116 . Protrusions  114  may have a tapered shape. Due to the tapered shape, protrusions  114  are wider in the X-Y plane near the surface of substrate  108  than at the tips of protrusions  114 . This causes the index of refraction of layer  112  to gradually change as a function of dimension Z, as shown by curve  118  in the graph on the right-hand side of  FIG. 5 . At the tips of protrusions  114  in layer  112 , the index of refraction of layer  112  matches the index of refraction of ambient air in the air gap that lies adjacent to layer  112 . At decreasing Z values (distance into the film), the widening lateral dimension of protrusions  114  causes the index of refraction n of layer  112  to gradually (continuously) rise (e.g., to n p , which is the index of refraction for bulk material of the type used to construct layer  112 ). The value of n p  may be equal to the index of refraction of substrate layer  108  or may have other suitable values. Layer  112  may be formed from a polymer or other suitable clear material. The textured surface of layer  112  may be formed using an embossing roller or other suitable equipment. If desired, broadband antireflection coatings (e.g., coatings with continuously varying indices of refraction such as layer  112  of  FIG. 5  may be formed using a film with nanoparticles or other structures. The use of a textured surface for layer  112  is merely illustrative. 
     By incorporating at least one layer of broadband antireflection coating material such as broadband antireflection layer  112  of  FIG. 5  into display  50  adjacent to air gap  66 , display  50  may be prevented from generating undesirable visible artifacts such as Newton&#39;s rings when a user presses against display cover layer  60  and flexes display layer  60  inwardly to bridge gap  66 . Because display  50  is therefore immune (or nearly immune) to producing undesired visible artifacts such as Newton&#39;s rings, component flatness variations may be tolerated that lead to occasional contact between the opposing surfaces that are adjacent to air gap  66 . This allows the size of air gap  66  to be minimized. 
       FIG. 6  is a cross-sectional diagram showing how substrate  108  (e.g., display cover layer  60 ) may be provided with an antireflection coating such as broadband antireflection layer  112  of  FIG. 5 . As shown in  FIG. 6 , layer  112  may be attached to the innermost (lower) surface of display cover layer  60  using a layer of adhesive such as pressure sensitive adhesive layer  120 . If desired, adhesive layer  120  may be omitted (e.g., by forming antireflection layer  112  directly on a substrate by depositing a polymer liquid and embossing and curing the liquid). 
     If desired, broadband antireflection coating layers may be formed on the upper and lower sides of gap  66 . As shown in  FIG. 7 , for example, broadband coating layers  112  may be formed on the innermost surface of substrate  108 A (e.g., touch sensor array layer  88  or display cover layer  60 ) and on the outermost surface of substrate  108 B (e.g., upper polarizer layer  74 ). Layers of adhesive such as pressure sensitive adhesive  120  may be used in attaching broadband antireflection coating layers  112 A and  112 B to substrates  108 A and  108 B, respectively. 
     As shown in  FIG. 8 , broadband antireflection coating  112  may be formed on lower substrate  108 B (e.g., upper polarizer  74  or other suitable display layer adjacent to air gap  66 ) and antireflection coating  122  (e.g., a coating such as antireflection coating  102  of  FIG. 3  or  102 ′ of  FIG. 4  or other suitable antireflection coating) may be formed on upper substrate layer  108 A. Upper substrate layer  108 A may be display cover layer  60  or touch sensor array  88  (as examples). Even though only a single layer of broadband antireflection coating is used in the arrangement of  FIG. 8 , the creation of Newton&#39;s rings may be satisfactorily suppressed. 
     In the illustrative configuration of  FIG. 9 , broadband antireflection coating  112  has been formed on upper substrate  108 A (e.g., display cover layer  60  or touch sensor array  88 ) and antireflection coating  122  (e.g., an antireflection coating such as coating  102  of  FIG. 3  or  102 ′ of  FIG. 4  or other suitable antireflection coating) may be formed on lower substrate layer  108 B. Upper substrate layer  108 A may be display cover layer  60  or touch sensor array  88  (as examples). Lower substrate layer  108 B may be, for example, upper polarizer layer  74 . As with the illustrative configuration of  FIG. 8 , the single layer of broadband antireflection coating that is used in the arrangement of  FIG. 9  may help suppress the creation of undesirable visual artifacts such as Newton&#39;s rings during the use of device  10 . 
     As shown in  FIGS. 8 and 9 , a layer of adhesive such as pressure sensitive adhesive  120  may be used in attaching broadband antireflection layer  112  to a substrate. If desired, pressure sensitive adhesive  120  may be omitted. For example, pressure sensitive adhesive  120  need not be used in a configuration in which layer  112  is formed by depositing a polymer on a substrate prior to use of an embossing tool to texture the surface of layer  112  to form protrusions  114  and valleys  116  of the type shown in  FIG. 5 . 
       FIG. 10  is a diagram showing how broadband antireflection coatings  112  may be formed on layers of display  50 . Initially, roller-based embossing equipment or other equipment may be used to form broadband antireflection layer  112  on a layer of pressure sensitive adhesive, backed by a release liner such as release liner  124 . 
     A cutting tool such as a cutting die, laser, or other equipment  126  may be used to cut out a portion of broadband antireflection coating  112 . 
     Equipment such as roller-based lamination equipment or other equipment may then be used to remove release liner  124  from adhesive layer  120  and attach broadband antireflection layer  112  to desired portions of display  50  (e.g., touch panel  88 , display cover layer  60 , upper polarizer  74  in display layers  70 , etc.). 
       FIG. 11  shows how separate autoclave operations may be used to laminate display layers such as layers  60 ,  88 , and  112  together in the portion of display structures that lie above air gap  66  and may be used to laminate display layers  70  together in the portion of display structures that lie below air gap  66 . During autoclave operations, pressure sensitive adhesive layers  120  may be cured. 
       FIG. 12  shows how autoclave operations may be used to laminate display layers such as layers  60  and  88  together (along with antireflection coating  122 ) in the portion of display structures that lie above air gap  66 .  FIG. 12  also shows how first and second autoclave operations may be used in forming display layers  70 . In a first autoclave operation, layers  124  and the pressure sensitive adhesive layer  120  in layers  124  may be attached to each other. In a second autoclave operation, layers  126  may be autoclaved and attached to layers  124 . 
     The configuration of  FIG. 11  may avoid the use of double autoclave operations in forming the lower portion of the display layers in display  50  (i.e., the layers below air gap  66 ) and may avoid the use of multiple broadband antireflection layers  112  to minimize costs. 
       FIG. 13  is a flow chart of illustrative steps involved in forming display  50 . At step  128 , antireflection films such as broadband antireflection film  112  may be formed. Broadband antireflection film  112  may be formed by running a sheet of polymer that lies on a release liner through an embossing tool to create a textured surface with protrusions  114  and valleys  116 . Broadband antireflection film  112  may also be formed by depositing a polymer material directly on a desired display surface and by performing embossing operations on the deposited polymer material. If desired, broadband antireflection film  112  may be formed using other types of material (e.g., material with embedded nanoparticles, etc.). The use of an embossing tool to form broadband antireflection film  112  is merely illustrative. 
     At step  130 , broadband antireflection film  112  and, if desired, antireflection coating  122  (e.g., wet antireflection coating  102  of  FIG. 3 , wet antireflection coating  102 ′ of  FIG. 4 , or other antireflection coatings) may be formed on the surfaces of display  50  adjacent to air gap  66 . Broadband antireflection film  112  may be attached using adhesive  120  or by depositing and processing the material for film  112  directly on a desired substrate. Antireflection coating  122  may be formed by depositing a hard coat layer followed by a relatively thin cover layer, as described in connection with  FIGS. 3 and 4 , by forming other types of wet antireflection films, or by forming antireflection coatings using other techniques. 
     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: 20120525
Publication Date: 20151020
Grant Date: 20151020
Priority Date: 20120525
Inventors: RAPPOPORT BENJAMIN M.
CHEN CHENG
DORJGOTOV ENKHAMGALAN
ZHONG JOHN Z.
CHEN WEI
Assignee: APPLE INC
CPC Classifications: [{"code": "G02F1/13338", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B1/11", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133502", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B1/118", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B1/118", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B1/118", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02F1/1333", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/13338", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B1/11", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B1/118", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02F1/133502", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02F1/1335", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B1/11", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 48577868