PATENT DOCUMENT

Publication Number: US-9025100-B2
Application Number: US-201213690304-A
Country: US
Kind Code: B2

Title: Display with shielding antireflection layer

Abstract:
An electronic device may be provided with a display such as a liquid crystal display. The liquid crystal display may have a color filter layer, a thin-film-transistor layer, and a layer of liquid crystal material between the color filter layer and the thin-film-transistor layer. A lower polarizer may be formed under the thin-film-transistor layer. An upper polarizer may be formed on the color filter layer. A shielding antireflection layer may be formed on the upper polarizer. The shielding antireflection layer may serve both as a shielding layer that protects against display damage due to electrostatic charge and as an antireflection coating that helps to minimize reflections from the surface of the display. The shielding antireflection layer may include low and high index of refraction layers and a conductive layer such as a transparent conductive oxide layer that provides shielding.

Claims:
What is claimed is: 
     
       1. A display, comprising:
 a display layer; 
 a polarizer layer on the display layer; 
 a shielding antireflection film on the polarizer layer, wherein the shielding antireflection film includes a plurality of dielectric layers and a transparent conductive layer, wherein a first dielectric layer of the plurality of dielectric layers is formed directly on the polarizer, and wherein a second dielectric layer of the plurality of dielectric layers having an index of refraction greater than the first dielectric layer is formed directly on the first dielectric layer of the plurality of dielectric layers, and wherein a third dielectric layer of the plurality of dielectric layers is formed directly on the second dielectric layer of the plurality of dielectric layers; and 
 a conductive structure that shorts the transparent conductive layer to ground. 
 
     
     
       2. The display defined in  claim 1  wherein the shielding antireflection film includes at least one layer of silicon dioxide. 
     
     
       3. The display defined in  claim 2  wherein the shielding antireflection film includes at least one niobium pentoxide layer. 
     
     
       4. The display defined in  claim 3  wherein the transparent conductive layer comprises a conductive oxide. 
     
     
       5. The display defined in  claim 4  wherein the transparent conductive layer comprises indium tin oxide. 
     
     
       6. The display defined in  claim 1  wherein the shielding antireflection layer includes six layers of material including five dielectric layers and an indium tin oxide layer. 
     
     
       7. The display defined in  claim 6  wherein three of the five dielectric layers comprise silicon dioxide. 
     
     
       8. The display defined in  claim 7  wherein two of the five dielectric layers comprise niobium pentoxide. 
     
     
       9. The display defined in  claim 6  wherein three of the five dielectric layers comprise low index of refraction layers and where two of the five dielectric layers have indices of refraction that are greater than the low index of refraction layers. 
     
     
       10. The display defined in  claim 9  wherein the indium tin oxide layer is interposed between one of the three low index of refraction layers and one of the two dielectric layers having indices of refraction greater than the low index of refraction layers. 
     
     
       11. The display defined in  claim 10  wherein the conductive structure shorts the indium tin oxide layer to ground. 
     
     
       12. The display defined in  claim 11  wherein the conductive structure comprises at least one metal pin that penetrates the shielding antireflection layer. 
     
     
       13. A display, comprising:
 a color filter layer; 
 a thin-film-transistor layer; 
 a layer of liquid crystal material between the color filter layer and the thin-film transistor layer; 
 a polarizer on the color filter layer; and 
 a shielding antireflection layer on the polarizer, wherein the shielding antireflection layer includes a conductive oxide layer configured to serve as an electrostatic shielding layer and includes a plurality of dielectric layers, wherein a first dielectric layer of the plurality of dielectric layers having an index of refraction lower than the conductive oxide layer is formed directly on the polarizer, and wherein a second dielectric layer of the plurality of dielectric layers having an index of refraction greater than the conductive oxide layer is formed directly on the first dielectric layer of the plurality of dielectric layers, and wherein a third dielectric layer of the plurality of dielectric layers is formed directly on the second dielectric layer of the plurality of dielectric layers. 
 
     
     
       14. The display defined in  claim 13  wherein the dielectric layers are interposed between the conductive oxide layer and the polarizer. 
     
     
       15. The display defined in  claim 13  further comprising a layer of dielectric on the conductive oxide layer. 
     
     
       16. The display defined in  claim 15  wherein the layer of dielectric on the conductive oxide layer comprises a layer of silicon dioxide. 
     
     
       17. The display defined in  claim 16  wherein the dielectric layers that are interposed between the conductive oxide layer and the polarizer include a plurality of low index of refraction layers and a plurality of high index of refraction layers each having an index of refraction greater than the low index of refraction layers. 
     
     
       18. The display defined in  claim 17  wherein the conductive oxide layer is formed on one of the high index of refraction layers. 
     
     
       19. An electronic device, comprising:
 a liquid crystal display having an upper polarizer with an upper surface; 
 a plurality of layers of material on the upper surface configured to form an antireflection coating for the liquid crystal display, wherein the plurality of layers of material include a plurality of dielectric layers including a plurality of low index of refraction layers and a plurality of high index of refraction layers each having an index of refraction greater than the low index of refraction layers and wherein the plurality of layers includes a conductive transparent layer on the plurality of dielectric layers; and 
 an additional low index of refraction layer formed directly on top of the conductive transparent layer, wherein one low index of refraction layer of the plurality of low index of refraction layers is formed directly on the upper surface of the upper polarizer, and wherein the additional low index of refraction layer and the low index of refraction layer formed directly on the upper surface of the upper polarizer have the same index of refraction. 
 
     
     
       20. The electronic device of  claim 19 , wherein the plurality of low index of refraction layers and the plurality of high index of refraction layers on the upper surface are arranged in an alternating pattern.

Description:
BACKGROUND 
     This relates generally to electronic devices, and more particularly, to electronic devices with displays. 
     Electronic devices often include displays. For example, cellular telephones and portable computers often include displays for presenting information to a user. 
     When touched by a user, a display may be exposed to electrostatic charge. Displays are often provided with electrostatic discharge shielding layers. An electrostatic shielding layer prevents electrostatic charge from imposing damaging electric fields on underlying display structures and thereby prevents damage to a display. Electrostatic shielding layers are formed from conductive materials to provide a low-resistance path through which electrostatic charge can be removed from display surfaces. Electrostatic shielding layers are also transparent to allow content on a display to be viewed by a user. 
     A commonly used material that is both transparent and conductive and that can therefore be used in forming an electrostatic discharge shielding layer is indium tin oxide. With one conventional arrangement, a layer of indium tin oxide is formed between the upper surface of a display color filter glass layer and the lower surface of an upper polarizer. Indium tin oxide electrostatic shielding layers with this type of conventional configuration may be satisfactory for providing adequate shielding and display transparency, but can give rise to undesirable light reflections from a display. In the presence of excessive reflections, content on a display may appear washed out and difficult to view by a user. 
     It would therefore be desirable to be able to provide improved displays having low reflectivity surfaces with electrostatic discharge shielding. 
     SUMMARY 
     An electronic device may be provided with a display such as a liquid crystal display. The liquid crystal display may have a color filter layer, a thin-film-transistor layer, and a layer of liquid crystal material between the color filter layer and the thin-film-transistor layer. A lower polarizer may be formed under the thin-film-transistor layer. An upper polarizer may be formed on the color filter layer. 
     A shielding antireflection layer may be formed on the upper polarizer. The shielding antireflection layer may serve both as a shielding layer that protects against display damage due to electrostatic charge and as an antireflection coating that helps to minimize reflections from the surface of the display. 
     The shielding antireflection layer may include low and high index of refraction layers that are formed in an alternating pattern on the surface of the color filter layer. The shielding antireflection layer may also include a conductive layer such as a layer of transparent conductive oxide that provides shielding. By forming shielding structures as part of an antireflection layer stack, shielding functions can be provided without creating undesired reflections. 
     The low index of refraction layers may be formed from a dielectric such as silicon dioxide. The high index of refraction layers may be formed from a dielectric such as niobium pentoxide. The transparent conductive oxide may be indium tin oxide. 
     The transparent conductive oxide may be located between one of the low index of refraction layers and one of the high index of refraction layers in the shielding 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 perspective view of an illustrative electronic device such as a laptop computer with a display having a shielding antireflection layer in accordance with an embodiment of the present invention. 
         FIG. 2  is a perspective view of an illustrative electronic device such as a handheld electronic device with a display having a shielding antireflection layer in accordance with an embodiment of the present invention. 
         FIG. 3  is a perspective view of an illustrative electronic device such as a tablet computer with a display having a shielding antireflection layer in accordance with an embodiment of the present invention. 
         FIG. 4  is a perspective view of an illustrative electronic device such as a computer display having a shielding antireflection layer in accordance with an embodiment of the present invention. 
         FIG. 5  is a cross-sectional side view of an illustrative display in accordance with an embodiment of the present invention. 
         FIG. 6  is cross-sectional side view of a shielding antireflection layer on a polarizer in a display in accordance with an embodiment of the present invention. 
         FIG. 7  is a cross-sectional side view of a system for forming multilayer display coatings such as a shielding antireflection layer in accordance with an embodiment of the present invention. 
         FIG. 8  is a cross-sectional side view of an illustrative display having a shielding antireflection coating in which a conductive shield layer has been shorted to ground by a conductive structure that makes contact with an exposed portion of the conductive shield layer in accordance with an embodiment of the present invention. 
         FIG. 9  is a cross-sectional side view of an illustrative display having a shielding antireflection coating in which a conductive shield layer has been shorted to ground by a conductive protrusion that makes contact with the conductive shield layer by penetrating a stack of thin-film layers in accordance with an embodiment of the present invention. 
         FIG. 10  is a flow chart of illustrative steps involved in forming a display with a shielding antireflection coating in accordance with an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices may include displays. The displays may be used to display images to a user. Illustrative electronic devices that may be provided with displays are shown in  FIGS. 1 ,  2 ,  3 , and  4 . 
       FIG. 1  shows how electronic device  10  may have the shape of a laptop computer having upper housing  12 A and lower housing  12 B with components such as keyboard  16  and touchpad  18 . Device  10  may have hinge structures  20  that allow upper housing  12 A to rotate in directions  22  about rotational axis  24  relative to lower housing  12 B. Display  14  may be mounted in upper housing  12 A. Upper housing  12 A, which may sometimes referred to as a display housing or lid, may be placed in a closed position by rotating upper housing  12 A towards lower housing  12 B about rotational axis  24 . 
       FIG. 2  shows how electronic device  10  may be a handheld device such as a cellular telephone, music player, gaming device, navigation unit, or other compact device. In this type of configuration for device  10 , housing  12  may have opposing front and rear surfaces. Display  14  may be mounted on a front face of housing  12 . Display  14  may, if desired, have openings for components such as button  26 . Openings may also be formed in display  14  to accommodate a speaker port (see, e.g., speaker port  28  of  FIG. 2 ). 
       FIG. 3  shows how electronic device  10  may be a tablet computer. In electronic device  10  of  FIG. 3 , housing  12  may have opposing planar front and rear surfaces. Display  14  may be mounted on the front surface of housing  12 . As shown in  FIG. 3 , display  14  may have an opening to accommodate button  26  (as an example). 
       FIG. 4  shows how electronic device  10  may be a computer display or a computer that has been integrated into a computer display. With this type of arrangement, housing  12  for device  10  may be mounted on a support structure such as stand  27 . Display  14  may be mounted on a front face of housing  12 . 
     The illustrative configurations for device  10  that are shown in  FIGS. 1 ,  2 ,  3 , and  4  are merely illustrative. In general, electronic device  10  may be a laptop computer, a computer monitor containing an embedded computer, a tablet computer, a cellular telephone, a media player, or other handheld or portable electronic device, a smaller device such as a wrist-watch device, a pendant device, a headphone or earpiece device, or other wearable or miniature device, a television, a computer display that does not contain an embedded computer, a gaming device, a navigation device, an embedded system such as a system in which electronic equipment with a display is mounted in a kiosk or automobile, equipment that implements the functionality of two or more of these devices, or other electronic equipment. 
     Housing  12  of device  10 , which is sometimes referred to as a case, may be formed of materials such as plastic, glass, ceramics, carbon-fiber composites and other fiber-based composites, metal (e.g., machined aluminum, stainless steel, or other metals), other materials, or a combination of these materials. Device  10  may be formed using a unibody construction in which most or all of housing  12  is formed from a single structural element (e.g., a piece of machined metal or a piece of molded plastic) or may be formed from multiple housing structures (e.g., outer housing structures that have been mounted to internal frame elements or other internal housing structures). 
     Display  14  may be a touch sensitive display that includes a touch sensor or may be insensitive to touch. Touch sensors for display  14  may be formed from an array of capacitive touch sensor electrodes, a resistive touch array, touch sensor structures based on acoustic touch, optical touch, or force-based touch technologies, or other suitable touch sensor components. 
     Display  14  for device  10  includes display pixels formed from liquid crystal display (LCD) components or other suitable image pixel structures. 
     A display cover layer may cover the surface of display  14  or a display layer such as a color filter layer or other portion of a display may be used as the outermost (or nearly outermost) layer in display  14 . The outermost display layer may be formed from a transparent glass sheet, a clear plastic layer, or other transparent member. 
     A cross-sectional side view of an illustrative configuration for display  14  of device  10  (e.g., for display  14  of the devices of  FIG. 1 ,  FIG. 2 ,  FIG. 3 ,  FIG. 4  or other suitable electronic devices) is shown in  FIG. 5 . As shown in  FIG. 5 , display  14  may include backlight structures such as backlight unit  42  for producing backlight  44 . During operation, backlight  44  travels outwards (vertically upwards in dimension Z in the orientation of  FIG. 5 ) and passes through display pixel structures in display layers  46 . This illuminates any images that are being produced by the display pixels for viewing by a user. For example, backlight  44  may illuminate images on display layers  46  that are being viewed by viewer  48  in direction  50 . 
     Display layers  46  may be mounted in chassis structures such as a plastic chassis structure and/or a metal chassis structure to form a display module for mounting in housing  12  or display layers  46  may be mounted directly in housing  12  (e.g., by stacking display layers  46  into a recessed portion in housing  12 ). Display layers  46  may form a liquid crystal display or may be used in forming displays of other types. 
     In a configuration in which display layers  46  are used in forming a liquid crystal display, display layers  46  may include a liquid crystal layer such a liquid crystal layer  52 . Liquid crystal layer  52  may be sandwiched between display layers such as display layers  58  and  56 . Layers  56  and  58  may be interposed between lower polarizer layer  60  and upper polarizer layer  54 . 
     Layers  58  and  56  may be formed from transparent substrate layers such as clear layers of glass or plastic. Layers  56  and  58  may be layers such as a thin-film transistor layer and/or a color filter layer. Conductive traces, color filter elements, transistors, and other circuits and structures may be formed on the substrates of layers  58  and  56  (e.g., to form a thin-film transistor layer and/or a color filter layer). Touch sensor electrodes may also be incorporated into layers such as layers  58  and  56  and/or touch sensor electrodes may be formed on other substrates. 
     With one illustrative configuration, layer  58  may be a thin-film transistor layer that includes an array of thin-film transistors and associated electrodes (display pixel electrodes) for applying electric fields to liquid crystal layer  52  and thereby displaying images on display  14 . Layer  56  may be a color filter layer that includes an array of color filter elements for providing display  14  with the ability to display color images. If desired, layer  58  may be a color filter layer and layer  56  may be a thin-film transistor layer. 
     During operation of display  14  in device  10 , control circuitry (e.g., one or more integrated circuits such as components  68  on printed circuit  66  of  FIG. 5 ) may be used to generate information to be displayed on display (e.g., display data). The information to be displayed may be conveyed from circuitry  68  to display driver integrated circuit  62  using a signal path such as a signal path formed from conductive metal traces in flexible printed circuit  64  (as an example). 
     Display driver integrated circuit  62  may be mounted on thin-film-transistor layer driver ledge  82  or elsewhere in device  10 . A flexible printed circuit cable such as flexible printed circuit  64  may be used in routing signals between printed circuit  66  and thin-film-transistor layer  58 . If desired, display driver integrated circuit  62  may be mounted on printed circuit  66  or flexible printed circuit  64 . Printed circuit  66  may be formed from a rigid printed circuit board (e.g., a layer of fiberglass-filled epoxy) or a flexible printed circuit (e.g., a flexible sheet of polyimide or other flexible polymer layer). 
     Backlight structures  42  may include a light guide plate such as light guide plate  78 . Light guide plate  78  may be formed from a transparent material such as clear glass or plastic. During operation of backlight structures  42 , a light source such as light source  72  may generate light  74 . Light source  72  may be, for example, an array of light-emitting diodes. 
     Light  74  from light source  72  may be coupled into edge surface  76  of light guide plate  78  and may be distributed in dimensions X and Y throughout light guide plate  78  due to the principal of total internal reflection. Light guide plate  78  may include light-scattering features such as pits or bumps. The light-scattering features may be located on an upper surface and/or on an opposing lower surface of light guide plate  78 . 
     Light  74  that scatters upwards in direction Z from light guide plate  78  may serve as backlight  44  for display  14 . Light  74  that scatters downwards may be reflected back in the upwards direction by reflector  80 . Reflector  80  may be formed from a reflective material such as a layer of white plastic or other shiny materials. 
     To enhance backlight performance for backlight structures  42 , backlight structures  42  may include optical films  70 . Optical films  70  may include diffuser layers for helping to homogenize backlight  44  and thereby reduce hotspots, compensation films for enhancing off-axis viewing, and brightness enhancement films (also sometimes referred to as turning films) for collimating backlight  44 . Optical films  70  may overlap the other structures in backlight unit  42  such as light guide plate  78  and reflector  80 . For example, if light guide plate  78  has a rectangular footprint in the X-Y plane of  FIG. 5 , optical films  70  and reflector  80  may have a matching rectangular footprint. 
     To provide display  14  with the ability to withstand damage from electrostatic charge when display  14  is contacted by external objects such as a user&#39;s finger or other body part, display  14  may be provided with an electrostatic discharge shielding layer such as electrostatic discharge shielding layer  112 . Layer  112  may be formed as part of antireflection layer  108 . 
     Conventional liquid crystal displays in which an electrostatic discharge shielding layer of indium tin oxide is formed on the upper surface of a color filter glass under an upper polarizer suffer from large reflections due to index of refraction mismatch between the indium tin oxide (with an index of 1.9) and adjacent layers such as the color filter glass (with an index of 1.5). In contrast, a shielding configuration of the type shown in  FIG. 6  in which layer  112  is integrated into antireflection layer  108  may simultaneously exhibit both low reflectivity and satisfactory electrostatic shielding. 
     As shown in  FIG. 6 , antireflection layer  108  may be formed on polarizer  54 . Adhesive layer  100  may be used to attach polarizer layer  54  to the upper surface of color filter layer  56  (e.g., a glass color filter layer substrate). 
     Antireflection layer  108  includes a stack of multiple layers of material with different indices of refraction. The number of layers of material, the thicknesses of the layers of material, and the indices of refractions of these layers of material are preferably selected so as to minimize the amount of reflected light  122  that is generated when ambient light  124  in the visible spectrum strikes display  14 . In this way, the stack of layers in layer  108  minimizes reflections and increases the visible contrast of display  14 . The presence of a conductive layer of material such as layer  112  in the antireflection stack allows layer  108  to serve as a shielding electrostatic discharge protection layer to prevent damage to the components of display  14  in the presence of electric charge. 
     In the configuration of  FIG. 6 , antireflection layer  108  includes a stack of six layers—conductive layer  112  and dielectric layers  110 ,  114 ,  116 ,  118 , and  120 . Other numbers of layers may be used in forming an antireflection stack for display  14 . The example of  FIG. 6  is merely illustrative. 
     The indices of refraction in an antireflection stack alternate between high and low indices of refraction. Layers such as layers  110 ,  116 , and  120  may, for example, be considered to be “low index” layers. Layers  112  and  114  can collectively be considered to form an upper “high index” layer. Layer  118  forms a lower “high index” layer. 
     In the configuration of  FIG. 6 , low index layers  110 ,  116 , and  120  have been formed from silicon dioxide (SiO 2 ) and exhibit an index of refraction of 1.45. Lower high index layer  118  has been formed from niobium pentoxide (Nb 2 O 5 ) and exhibits an index of refraction of 2.1. Layers  112  and  114 , which collectively form the upper high index layer, have been formed from indium tin oxide (having an index of refraction of 1.9) and niobium pentoxide (having an index of refraction of 2.1). Other materials may be used for these layers if desired. For example, layer  112  may be formed from a transparent conductive layer other than indium tin oxide (e.g., another conducting oxide such as aluminum zinc oxide). Layers  110 ,  114 ,  116 , and  118  may be formed oxides other than silicon dioxide and niobium pentoxide, may be formed from nitrides, etc.). The materials used in the example of  FIG. 6  are merely illustrative. 
     The thickness of layer  110  may be greater than 1000 angstroms and the thicknesses of layers  116 ,  118 , and  120  may be less than 2000 angstroms (as examples). The thickness of layer  112  is preferably configured so that layer  112  exhibits a satisfactorily low sheet resistance for serving as a shielding layer (e.g., 500-1000 ohms per square or other suitable value such as less than 1000 ohms per square, less than 2000 ohms per square, etc.). When the sheet resistance for layer  112  is sufficiently low, layer  112  will be sufficiently conductive to discharge electrostatic charge to ground. 
     To ensure that layers  112  and  114  can collectively serve as the upper high index layer in the thin-film stack of layer  108 , the thicknesses of layers  112  and  114  can be chosen to exhibit a total optical thickness that is equal to the optical thickness of a single uniform high index layer such as a single niobium oxide layer of the type that might otherwise be used in forming an antireflection stack that does not include a conducting oxide layer. Consider, as an example, a five layer antireflection stack with alternating silicon dioxide and niobium oxide layers. This type of antireflection stack might use an upper niobium oxide layer with a thickness of 1000 angstroms. Because niobium oxide has an index of refraction of 2.1, the optical thickness of this layer (and therefore the target optical thickness for layers  112  and  114  in the  FIG. 6  arrangement) would be 2.1* 1000=2100. Layers  112  and  114  in an arrangement of the type shown in  FIG. 6  can be configured to have a collective optical thickness of 2100, so that stack  108  will perform as an antireflection layer. 
     Although transparent, indium tin oxide tends to absorb more visible light than dielectric oxides such as silicon dioxide and niobium oxide for a given thickness. To minimize light absorption, the thickness of indium tin oxide layer  112  may therefore be maintained at a relatively small value. For example, it may be desirable to limit the thickness of indium tin oxide layer  112  to a value in the range of 200-300 angstroms or other value that provides satisfactory sheet resistance (as examples). 
     The thickness of niobium pentoxide layer  114  can be adjusted to ensure that the total optical thickness of layers  112  and  114  has its desired value (2100 in this example). In a scenario in which the thickness of indium tin oxide layer  112  is 250 angstroms, as an example, the optical thickness contribution of layer  112  will be 1.9*250=475 and the desired thickness T for niobium pentoxide layer  114  will be T=(2100−475)/2.1=774 angstroms. Layer  114  may be thicker in scenarios in which layer  112  is thinner and layer  114  may be thinner in scenarios in which layer  112  is thicker. If desired, different thicknesses may be used (e.g., in an antireflection stack having different oxides with correspondingly different indices of refraction and/or a different conductive material for layer  112 ). The position of layer  112  (and layer  114 ) may, if desired, be swapped with that of layer  118 . In general, however, positions for conductive layer  112  that are closer to the exposed outer surface of antireflection stack  108  are preferred as more outwardly positioned conductive layers will be closer to sources of electrostatic charge and will tend to provide superior shielding. 
     If desired, an anti-smudge coating layer such as a layer of fluorinated material that is a few nanometers thick may be formed on the upper surface of layer  108 . This type of coating is not optically significant and is therefore not shown in  FIG. 6 . 
     Antireflection layer  108  may be formed on the upper surface of upper polarizer  54 . Polarizer  54  may be formed from multiple layers of material that are attached together. Polarizer film  104  may be formed from a stretched polymer such as stretched polyvinyl alcohol (PVA) and may therefore sometimes be referred to as a PVA layer. Iodine may be placed on the stretched PVA film so that iodine molecules align with the stretched film and form the polarizer. Other types of polarizer films may be used if desired. 
     Polarizer film  104  may be sandwiched between layers  106  and  102 . Layers  106  and  102  may be formed from a material such as tri-acetyl cellulose (TAC) and may sometimes be referred to as TAC films or may be formed from other polymers. The TAC films may help hold the PVA film in its stretched configuration and may protect the PVA film. Other films may be attached to polarizer film  104  if desired. 
     A layer of adhesive such as adhesive layer  100  may be used to help attach polarizer  54  to the upper surface of display layers  46  (i.e., color filter  56 ). The thickness of polarizer  54  may be about 50-200 microns or 90-180 microns (as examples). 
     Polarizer  54  and/or an individual TAC film such as film  106  may be coated with layers  108  using physical vapor deposition equipment or other deposition tools. Illustrative physical vapor deposition equipment of the type that may be used to form the layers of material in antireflection layer  108  is shown in  FIG. 7 . As shown in  FIG. 7 , equipment  126  may include rollers such as rollers  140  and a drum such as drum  134 . During operation, film  128  may move in direction  130  while being guided along rollers  140  and around drum  134 . Drum  134  may rotate in direction  136  about rotational axis  132 . The components of equipment  126  may be enclosed within a vacuum chamber. Physical vapor deposition equipment such as sputtering or evaporation equipment or other deposition equipment may be used to deposit materials from targets  138  onto outer surface  141  of film  128 . Film  128  may be a flexible polymer film such as TAC layer  106  or polarizer layer  54 . Targets  138  may be used to deposit materials such as indium tin oxide for layer  112 , silicon dioxide for layers  110 ,  116 , and  120 , and niobium pentoxide for layers  114  and  118 , thereby forming stack  108  on film  128 . After forming thin film coatings for stack  108  using deposition equipment  126  of  FIG. 7 , film  128  may be combined with the other structures of display  14  to form a display  14 . 
     When installing display  14  within device  10 , a grounding path may be formed between conductive shielding layer  112  and a source of ground potential such as a grounded metal housing (e.g., housing  12 ). A cross-sectional side view of a portion of display  14  mounted in housing  12  of device  10  is shown in  FIG. 8 . With the illustrative grounding configuration of  FIG. 8 , a portion of the surface of layer  112  such as region  142  of  FIG. 8  may be exposed by etching or otherwise removing overlapping portions of silicon dioxide layer  110 . This allows conductive structures  114  to electrically couple layer  112  to metal housing  12  or other grounded structures. When layer  112  is shorted to ground in this way, electrostatic charge that is placed on the surface of layer  112  may be discharged to protect the structures in display  14  from damage. Conductive structures  114  may include conductive tape such as metal tape, a silver nanowire ring, strips of metal, conductive paint (e.g., silver paint), conductive adhesive such as conductive epoxy or anisotropic conductive film, or other conductive structures. If desired, grounding may be provided using metal structures other than metal housing  12  (e.g., when forming an electrostatic charge discharge path in a device without a metal housing or when it is desired to use an internal cable or other signal path to ground layer  114 ). 
     If desired, a pin or other protrusion such as metal grounding pin  146  of  FIG. 9  may penetrate layer  108  and thereby form an electrical connection between layer  112  and metal housing  12  or other ground structures. It is not necessary to separately remove a portion of layer  110  with this type of configuration, because pin  146  breaks through layer  110  and shorts layer  112  to ground. 
     Illustrative steps involved in forming device  10  and display  14  with a shielding antireflection layer such as shielding antireflection layer  108  are shown in  FIG. 10 . 
     At step  150 , multilayer stack  108  may be formed on a substrate such as film  128  of  FIG. 7 . Multilayer stack  108  may include dielectric layers such as layers of high and low index of refraction oxides and may include a conductive layer such as a layer of indium tin oxide or other conductive oxide. The layers of stack  108  may be configured to form an antireflection coating (e.g., the thicknesses and dielectric constants of the layers of stack  108  may be configured to minimize surface reflections at visible wavelengths). The presence of the conductive layer (e.g., conductive layer  112 ) in layer  108  allows layer  108  to serve as an electrostatic shield in addition to serving as an antireflection layer. Film  128  may be a portion so of a polarizer layer such as TAC film layer  106  or may be a flexible sheet of polarizer material  54 . In configurations in which TAC layer  106  is coated with layer  108 , subsequent processing steps may be used to form polarizer  54 . 
     Following formation of polarizer  54 , polarizer  54  and shielding antireflection layer  108  on top of polarizer  54  may be laminated to the upper surface of color filter layer  56  using adhesive  100  (step  152 ). 
     At step  154 , display  14  may be installed within device  10 . When installing display  14  within device  10 , conductive structures such as conductive structures  144  of  FIG. 8  or conductive structures such as conductive pin  146  of  FIG. 9  may be used to short conductive shielding layer  112  in shielding antireflection layer  108  to ground (e.g., to housing  12  or other metal structures in device  10 ). 
     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: 20121130
Publication Date: 20150505
Grant Date: 20150505
Priority Date: 20121130
Inventors: DORJGOTOV ENKHAMGALAN
KUWABARA MASATO
CHEN CHENG
CHEN WEI
ZHONG JOHN Z.
Assignee: APPLE INC
CPC Classifications: [{"code": "G02F1/133502", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05B33/22", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02F2202/22", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F2202/22", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133502", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05B33/22", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 50825137