PATENT DOCUMENT

Publication Number: US-9753317-B2
Application Number: US-201313915024-A
Country: US
Kind Code: B2

Title: Methods for trimming polarizers in displays using edge protection structures

Abstract:
An electronic device is provided with a display such as a liquid crystal display. The display has a layer of liquid crystal material sandwiched between an upper display layer such as a color filter layer and a lower display layer such as a thin-film-transistor layer. An upper polarizer is formed on the upper surface of the color filter layer. A lower polarizer is formed on the lower surface of the thin-film-transistor layer. To protect display layers such as the color filter layer and the thin-film-transistor layer, a coating is deposited on a peripheral edge of the display layer. A laser is used to cut through portions of the polarizer that overhang the display layer while also cutting through the coating on the peripheral edge of the display layer. Following laser trimming operations, the coating is flush with an edge surface of the polarizer.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a display layer having a peripheral edge surface, wherein the display layer includes a color filter substrate and a thin-film transistor substrate and wherein the peripheral edge surface comprises a portion of the color filter substrate and a portion of the thin-film transistor substrate; 
 a polarizer having a peripheral edge surface and having an inner surface attached to and in physical contact with the display layer; and 
 a coating having opposing inner and outer surfaces, wherein the inner surface is on the peripheral edge surface of the display layer, and wherein the polarizer extends beyond the peripheral edge surface of the display layer such that the outer surface of the coating is coplanar with the peripheral edge surface of the polarizer. 
 
     
     
       2. The electronic device defined in  claim 1  wherein the coating comprises light-cured adhesive. 
     
     
       3. The electronic device defined in  claim 1  wherein the coating comprises polymer. 
     
     
       4. The electronic device defined in  claim 1  wherein the coating comprises silicone. 
     
     
       5. The electronic device defined in  claim 1  wherein the peripheral edge surface of the display layer is curved. 
     
     
       6. The electronic device defined in  claim 1  wherein the coating and the peripheral edge surface of the polarizer form an outermost edge surface of the electronic device. 
     
     
       7. The electronic device defined in  claim 1  wherein the display layer comprises at least one layer of glass. 
     
     
       8. The electronic device defined in  claim 1  wherein the display layer comprises:
 liquid crystal material interposed between the color filter substrate and the thin-film-transistor substrate. 
 
     
     
       9. The electronic device defined in  claim 1  further comprising:
 an electronic device housing, wherein the peripheral edge surface of the polarizer and the coating abut an inner surface of the electronic device housing. 
 
     
     
       10. The electronic device defined in  claim 1  wherein the display layer and the coating each have an upper surface, wherein the polarizer is in physical contact with the upper surface of the display layer, and wherein the upper surface of the coating is coplanar with the upper surface of the display layer. 
     
     
       11. The electronic device defined in  claim 1  wherein the coating and the polarizer share a laser-cut edge. 
     
     
       12. A method, comprising:
 attaching an inner surface of a polarizer layer to a display layer such that the inner surface of the polarizer layer is in physical contact with the display layer; 
 coating a peripheral edge surface of the display layer with a coating layer, wherein the display layer comprises a color filter substrate and a thin-film transistor substrate and wherein the peripheral edge surface comprises a portion of the color filter substrate and a portion of the thin-film transistor substrate; and 
 while the peripheral edge surface of the display layer is coated with the coating layer, trimming the polarizer layer and the coating to form a planar edge surface, wherein the coating layer has opposing inner and outer surfaces, wherein the inner surface is on the peripheral edge surface, wherein the planar edge surface is formed from a peripheral edge surface of the polarizer layer and the outer surface of the coating layer, and wherein the polarizer layer extends beyond the peripheral edge surface of the display layer. 
 
     
     
       13. The method defined in  claim 12  wherein forming the display layer comprises machining a display layer that includes the color filter substrate attached to the thin-film-transistor substrate. 
     
     
       14. The method defined in  claim 12  further comprising:
 with surface activation equipment, activating the peripheral edge surface of the display layer prior to coating the peripheral edge surface of the display layer with the coating layer. 
 
     
     
       15. The method defined in  claim 14  wherein the surface activation equipment comprises plasma surface activation equipment. 
     
     
       16. The method defined in  claim 14  wherein activating the peripheral edge surface of the display layer comprises:
 with a computer-controlled positioner, moving a plasma jet around the peripheral edge surface of the display layer; and 
 with the plasma jet, discharging plasma onto the peripheral edge surface of the display layer as the plasma jet is moved by the computer-controlled positioner. 
 
     
     
       17. The method defined in  claim 12  wherein the coating layer comprises a light-curable coating layer, the method further comprising:
 with a light source, curing the light-curable coating layer. 
 
     
     
       18. The method defined in  claim 12  wherein the coating layer comprises a thermal-cure coating layer, the method further comprising:
 with a heat source, curing the thermal-cure coating layer. 
 
     
     
       19. A method, comprising:
 laminating an oversized polarizer onto a glass substrate having a peripheral edge so that an overhanging portion of the polarizer overhangs the peripheral edge and so that the oversized polarizer is in physical contact with the glass substrate, wherein the glass substrate comprises a color filter substrate and a thin-film transistor substrate and wherein the peripheral edge of the glass substrate comprises a portion of the color filter substrate and a portion of the thin-film transistor substrate; 
 with coating deposition equipment, dispensing a coating onto the peripheral edge, wherein the coating has an inner surface on the peripheral edge; and 
 with a laser, cutting through the overhanging portion of the polarizer and the coating such that an outer surface of the coating is coplanar with a peripheral edge surface of the polarizer, wherein the polarizer extends beyond the peripheral edge of the glass substrate after cutting through the overhanging portion of the polarizer. 
 
     
     
       20. The method defined in  claim 19  wherein the laser comprises an infrared laser. 
     
     
       21. The method defined in  claim 19  wherein the laser comprises a visible light laser. 
     
     
       22. The method defined in  claim 19  wherein the cutting comprises using a camera to determine relative positions between the peripheral edge of the glass substrate and a laser beam. 
     
     
       23. The method defined in  claim 19  wherein cutting through the overhanging portion of the polarizer and the coating comprises exposing a planar edge surface, wherein the planar edge surface includes the peripheral edge surface of the polarizer and the outer surface of the coating.

Description:
This application claims priority to U.S. provisional patent application No. 61/745,117 filed Dec. 21, 2012, which is hereby incorporated by reference herein in its entirety. 
    
    
     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. 
     Displays such as liquid crystal display have polarizers. The polarizers are formed from polymer layers that are laminated to glass display layers. It may be desirable to ensure that a polarizer layer has the same size as an associated glass display layer. If the polarizer is too large, the edge of the polarizer will overhang the edge of the glass display layer, which in turn can lead to polarizer peeling. If the polarizer is too small, the edge of the display will have an unsightly visible polarizer edge. Although the polarizer edge may be covered with a plastic bezel, the use of a bezel reduces the visible area of a display and can make the display unattractive. 
     It would therefore be desirable to be able to provide improved displays with polarizers for electronic devices. 
     SUMMARY 
     An electronic device is provided with a display such as a liquid crystal display mounted in an electronic device housing. The display has a layer of liquid crystal material sandwiched between an upper display layer such as a color filter layer and a lower display layer such as a thin-film-transistor layer. 
     An upper polarizer is formed on the upper surface of the color filter layer. A lower polarizer is formed on the lower surface of the thin-film-transistor layer. Additional display structures provide backlight for the display. 
     To protect display layers such as the color filter layer and the thin-film-transistor layer, a coating is deposited on a peripheral edge of the display layer. A laser is used to cut through portions of the polarizer that overhang the display layer while also cutting through the coating on the peripheral edge of the display layer. Following laser trimming operations, the coating is flush with an edge surface of the polarizer. The coating provides protection to the display layers while also providing support to the edge portions of the polarizer. 
     Further features, their 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 display structures in accordance with an embodiment. 
         FIG. 2  is a perspective view of an illustrative electronic device such as a handheld electronic device with display structures in accordance with an embodiment. 
         FIG. 3  is a perspective view of an illustrative electronic device such as a tablet computer with display structures in accordance with an embodiment. 
         FIG. 4  is a perspective view of an illustrative electronic device such as a computer display with display structures in accordance with an embodiment. 
         FIG. 5  a cross-sectional side view of an illustrative display of the type that may be used in devices of the types shown in  FIGS. 1, 2, 3, and 4  in accordance with an embodiment. 
         FIG. 6  is a cross-sectional side view of an illustrative polarizer layer in accordance with an embodiment. 
         FIG. 7  is a perspective view of an illustrative panel of display layers that includes display structures for forming multiple individual displays in accordance with an embodiment. 
         FIG. 8  is a diagram of an illustrative system being used to form individual display layers from a panel of display layers in accordance with an embodiment. 
         FIG. 9  is a diagram of an illustrative system being used to laminate a polarizer to a display layer in accordance with an embodiment. 
         FIG. 10  is a diagram of an illustrative system being used to activate one or more surfaces of a display layer in accordance with an embodiment. 
         FIG. 11  is a diagram of an illustrative system that is forming an edge coating on a display layer of the type shown in  FIG. 8  in accordance with an embodiment. 
         FIG. 12  is a top view of an illustrative display layer with an edge coating in accordance with an embodiment. 
         FIG. 13  is a diagram of an illustrative system being used to laminate a polarizer to a display layer with a protective edge coating in accordance with an embodiment. 
         FIG. 14  is diagram of an illustrative system in which laser-based equipment is being used to trim a polarizer and an edge coating on a display layer in accordance with an embodiment. 
         FIG. 15  is side view of an illustrative focusing lens and focused laser beam of the type used in laser trimming a polarizer and an edge coating on a display layer with the equipment of  FIG. 14  in accordance with an embodiment. 
         FIG. 16  is a cross-sectional side view of illustrative edge portions of a polarizer and an edge coating being trimmed from display structures to form a flush edge in accordance with an embodiment. 
         FIG. 17  is a cross-sectional side view of a portion of an illustrative electronic device in which display structures are partially enclosed in a C-shaped trim structure and mounted in an electronic device housing in accordance with an embodiment. 
         FIG. 18  is a cross-sectional side view of a portion of an illustrative electronic device in which display structures are partially enclosed in an L-shaped trim structure and mounted in an electronic device housing in accordance with an embodiment. 
         FIG. 19  is a cross-sectional side view of a portion of an illustrative electronic device in which display structures are mounted in an electronic device housing in accordance with an embodiment. 
         FIG. 20  is a cross-sectional side view of illustrative display structures in which the edge surface of a polarizer and the edge surface of a protective coating on a display layer together form an outermost edge surface of an electronic device in accordance with an embodiment. 
         FIG. 21  is a flow chart of illustrative steps involved in forming electronic devices and displays by trimming polarizers on displays in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Displays in electronic devices such as liquid crystal displays may be provided with polarizers. Illustrative electronic devices that have displays with polarizers are shown in  FIGS. 1, 2, 3, and 4 . 
     Electronic device  10  of  FIG. 1  has the shape of a laptop computer and has upper housing  12 A and lower housing  12 B with components such as keyboard  16  and touchpad  18 . Device  10  has hinge structures  20  to allow upper housing  12 A to rotate in directions  22  about rotational axis  24  relative to lower housing  12 B. Display  14  is mounted in upper housing  12 A. Upper housing  12 A, which may sometimes referred to as a display housing or lid, is placed in a closed position by rotating upper housing  12 A towards lower housing  12 B about rotational axis  24 . 
       FIG. 2  shows an illustrative configuration for electronic device  10  based on 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  has opposing front and rear surfaces. Display  14  is mounted on a front face of housing  12 . Display  14  may have an exterior layer that includes openings for components such as button  26  and speaker port  28 . 
     In the example of  FIG. 3 , electronic device  10  is a tablet computer. In electronic device  10  of  FIG. 3 , housing  12  has opposing planar front and rear surfaces. Display  14  is mounted on the front surface of housing  12 . As shown in  FIG. 3 , display  14  has an external layer with an opening to accommodate button  26 . 
       FIG. 4  shows an illustrative configuration for electronic device  10  in which device  10  is a computer display or a computer that has been integrated into a computer display. With this type of arrangement, housing  12  for device  10  is mounted on a support structure such as stand  27 . Display  14  is 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, is 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  includes 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  illuminates 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  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  include a liquid crystal layer such a liquid crystal layer  52 . Liquid crystal layer  52  is sandwiched between display layers such as display layers  58  and  56 . Layers  56  and  58  are interposed between lower polarizer layer  60  and upper polarizer layer  54 . 
     Layers  58  and  56  are formed from transparent substrate layers such as clear layers of glass or plastic. Layers  56  and  58  are layers such as a thin-film transistor layer (e.g., a thin-film-transistor substrate such as a glass layer coated with a layer of thin-film transistor circuitry) and/or a color filter layer (e.g., a color filter layer substrate such as a layer of glass having a layer of color filter elements such as red, blue, and green color filter elements arranged in an array). Conductive traces, color filter elements, transistors, and other circuits and structures are 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  is 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  is 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  and/or other circuitry) is used to generate information to be displayed on display  14  (e.g., display data). The information to be displayed is 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 circuitry such as display driver integrated circuit  62  of  FIG. 5  is 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  is 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  is 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  include a light guide plate such as light guide plate  78 . Light guide plate  78  is 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  generates light  74 . Light source  72  may be, for example, an array of light-emitting diodes. 
     Light  74  from one or more light sources such as light source  72  is coupled into one or more corresponding edge surfaces such as edge surface  76  of light guide plate  78  and is distributed in dimensions X and Y throughout light guide plate  78  due to the principal of total internal reflection. Light guide plate  78  includes light-scattering features such as pits or bumps. The light-scattering features are 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  serves as backlight  44  for display  14 . Light  74  that scatters downwards is reflected back in the upwards direction by reflector  80 . Reflector  80  is 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  include optical films  70 . Optical films  70  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  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  preferably have a matching rectangular footprint. 
     The outermost layer of display  14  may be a protective display layer such as a layer of glass that covers layers  46  or a display layer such as color filter layer  56  (e.g., a glass substrate layer in layer  56 ) may serve as the outermost structural layer in display  14 . When display layer  56  is used as the outermost substrate layer in display  14 , visible border structures in display  14  can be minimized by accurately trimming polarizer  54  along the edge of layer  56 . Polarizing trimming operations can be performed using lasers, cutting blades (knife edges), or other trimming equipment. Care should be taken during trimming operations not to damage display layer  56 . As an example, care should be taken not to induce thermal damage to a glass substrate in layer  56  during laser trimming operations or mechanical damage to a glass substrate in layer  56  during cutting blade trimming operations. 
     A cross-sectional side view of an illustrative polarizer layer in display  14  is shown in  FIG. 6 . Polarizer layer  54  of  FIG. 6  is an upper polarizer such as upper polarizer  54  of  FIG. 5 . Lower polarizer layers such as lower polarizer  60  may be constructed similarly. 
     In the example of  FIG. 6 , polarizer  54  is formed from multiple layers of material that are attached together. Polarizer film  94  is 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  94  is sandwiched between layers  92  and  96 . Layers  92  and  96  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  94  if desired. 
     Coating layer  90  includes one or more films of material that provide polarizer  54  with desired surface properties. For example, layer  90  may be formed from materials that provide polarizer  54  with antiglare (light diffusing) properties, antireflection properties, scratch resistance, fingerprint resistance, and other desired properties. Layer  90  preferably is formed from one or more layers of material such as antireflection (AR) layers (e.g., films formed from a stack of alternating high-index-of-refraction and low-index-of-refraction layers), antiglare layers, antireflection-antiglare layers, oleophobic layers, antiscratch coatings, and other coating layers. The functions of these layers need not be mutually exclusive. For example, an antiglare film in coating  90  may help provide polarizer  54  with scratch resistance. 
     Polarizer  54  can be provided with a layer of adhesive such as adhesive layer  98  to help attach polarizer  54  to the upper surface of display layers  46  (i.e., color filter  56  of  FIG. 5 ). The thickness of polarizer  54  may be about 50-200 microns or 90-180 microns (as examples). During manufacturing operations, adhesive  98  attaches polarizer  54  to the upper surface of color filter layer  56 . 
     Trimming operations are preferably used to trim the edge of polarizer  54  to match the edge of a coating on color filter layer  56 . 
     Display layers can be formed from larger sheets of material. For example, as shown in  FIG. 7 , a first oversized glass layer such as layer  560  can include color filter structures for forming multiple color filter layers for multiple displays. A second oversized glass layer such as layer  580  can include thin-film-transistor circuitry for forming multiple thin-film-transistor layers for multiple displays. Liquid crystal material  520  is sandwiched between oversized glass layer  560  and oversized glass layer  580 , thus forming oversized display layer  100  (e.g., a panel of display layers). Oversized display layer  100  therefore includes display structures (e.g., color filter structures, thin-film transistor circuitry, liquid crystal material, and other suitable display structures) for forming multiple individual displays. Layer  100  may include one or more layers of glass, ceramic, polymer, or other suitable substrate materials. 
     Following formation of oversized display layer  100 , layer  100  is divided into smaller pieces. As shown in  FIG. 8 , equipment such as equipment  122  is used to divide layer  100  into smaller pieces such as substrate  108 . Equipment  122  may be substrate cutting equipment such as water-jet cutting equipment, laser cutting equipment, sawing equipment, machining equipment, or other equipment for dividing layer  100  into smaller pieces. In the illustrative configuration of  FIG. 8 , equipment  122  includes a computer-controlled positioner such as positioner  104  and a scribing tool such as scribing tool  102 . Positioner  104  moves scribing tool  102  in a desired pattern over the surface of layer  100  to form scribe lines. Manual and/or automated equipment may then be used to break layer  100  along the scribe lines to form separate pieces of layer  100  such as pieces  106  and  108 . Pieces  106  and  108  each have the size and shape of display  14  (e.g., rectangular display-sized pieces of glass). 
     Following the use of scribing operations or other operations to separate out individual display structures such as display-sized display layer  108  from oversized layer  100  using equipment  122 , machining equipment  124  or other edge treatment equipment is used to modify edge surface  100  of the peripheral edge of layer  108 . In the illustrative configuration of  FIG. 8 , equipment  124  includes computer-controlled positioner  112  and machining tool head  114 . Head  114  has a surface profile that is configured to ease the sharp corners in layer  108  (e.g., by rounding the upper and lower edges of layer  108 , by beveling the upper and lower edges of layer  108 , etc.). 
     During operation, positioner  112  rotates machining tool head  114  about rotational axis  116  in direction  118  while moving head  114  along the edge of layer  108 , thereby machining edge surface  110  of layer  108  into a desired shape. As shown at the bottom of  FIG. 8 , equipment  124  can provide layer  108  with a machined profile for surface  110  such as rounded profile  120  (e.g., edge  110  can be formed from a curved surface). 
     Machined glass layer  108  is used as a display layer for display  14 . In the illustrative example of  FIG. 8 , glass layer  108  includes multiple display layers such as color filter layer  56  and thin-film-transistor layer  58 . Liquid crystal material  52  is interposed between color filter layer  56  and thin-film-transistor layer  58 . This is, however, merely illustrative. If desired, layer  108  may be a color filter layer that has not yet been attached to a thin-film-transistor layer or layer  108  may include additional display structures. 
     Display layer  108  is sometimes referred to herein as glass layer  108 . However, it should be understood that layer  108  can include one or more plastic layers, one or more ceramic layers, or one or more layers of other transparent materials. The use of one or more glass layers to form display layer  108  is merely illustrative. 
       FIG. 9  is a system diagram showing how polarizer  54  may be attached to substrate layer  108 . In the illustrative configuration of  FIG. 9 , lamination equipment  138  is being used to laminate polarizer  54  to substrate layer  108 . Lamination equipment  138  may include a roller laminator, vacuum lamination equipment, or other equipment for attaching polarizer  54  to substrate  108 . When attached using roller-based lamination equipment or other lamination equipment, adhesive layer  98  ( FIG. 6 ) attaches the lower surface of polarizer  54  to the upper surface of display layer  108  to form display structures  140 , as shown in the bottom of  FIG. 9 . 
     In display structures  140 , polarizer  54  has larger lateral dimensions than the corresponding lateral dimensions of layer  108 . As a result, portions of polarizer layer  54  extend laterally beyond edge  110  of substrate  108  to form overhanging (overlapping) edge portions  142  of layer  54 . Excess portion of polarizer  54  such as overhanging edge portions  142  can be removed following attachment of polarizer layer  54  to glass layer  108 . For example, laser-based trimming equipment or other suitable trimming equipment can be used to remove some or all of overhanging edge portions  142  of polarizer layer  54 . 
     To protect glass layer  108  from damage while supporting the edge of polarizer  54  during polarizer trimming operations, it may be desirable to provide glass layer  108  with edge protection. Edge protection structures can also provide a flush edge at the periphery of layer  108  that would otherwise be difficult to achieve due to curved edge surface  110  of layer  108 . With one suitable arrangement, peripheral edge  110  of layer  108  is covered with edge protection structures such as a protective coating. The edge protection structures may be formed from resin, epoxy, adhesive, sealant, other polymer-based materials (e.g., silicone or other elastomeric polymer materials, hard plastic materials, etc.), ceramic, metal, or other coatings or structures. As examples, peripheral edge  110  can be covered with light-cured resin, light-cured adhesive, or silicone such as black, clear, or white silicone. 
     Edge  110  can optionally be treated prior to applying the protective coating in order to promote bonding at edge surfaces  110  with the protective coating.  FIG. 10  is a diagram showing how edge  110  of layer  108  can be treated with bonding promotion equipment prior to application of protective coatings. In the example of  FIG. 10 , equipment such as surface activation equipment  200  is being used to activate edge surface  110  of layer  108 . Equipment  200  includes computer-controlled positioner  206 , dispensing head  202 , and nozzle  204 . Equipment  200  may, for example, be a plasma jet configured to discharge a stream of plasma such as plasma  208  onto edge surface  110  of substrate  108 . During operation, plasma  208  is discharged from dispensing head  202  via nozzle  204  while positioner  206  runs head  202  around the periphery of layer  108 , thereby forcing plasma  208  onto edge surfaces  110  of layer  108 . Plasma  208  alters the surface properties of edge surfaces  110  of layer  108  such that surfaces  110  are better suited for coating and/or adhesive bonding (e.g., by removing organic materials from surfaces  110 , by altering the surface tension of surfaces  110 , by increasing the wettability of surfaces  110 , etc.). 
     If desired, other types of equipment may be used to treat edge surfaces  110  of layer  108  with plasma  208 . For example, layer  108  (and polarizer  54 , if desired), can be placed in a chamber which is subsequently filled with ionized gas to which edge surfaces  110  of layer  108  are exposed. With this type of arrangement, protective coatings or removable protective structures can be placed over layers or portions of layers that are not to be exposed to the plasma. 
     Other suitable types of surface activation equipment that can be used to treat edge surfaces  110  of layer  108  prior to coating with protective coatings or structures include corona treatment equipment, flame treatment equipment, chemical treatment equipment, surface abrading equipment, etc. The example of  FIG. 10  in which edge surfaces  110  are activated using plasma  208  is merely illustrative. Other edge treatment operations such as cleaning and degreasing operations can be performed on edge surfaces  110  prior to surface activation. If desired, edge surfaces  110  can be coated with protective materials without performing surface activation. The step of using equipment  200  to activate surfaces  110  prior to coating with edge protection structures is optional. 
       FIG. 11  is a diagram showing how edge  110  of layer  108  can be covered with a protective coating. In the example of  FIG. 11 , coating deposition equipment  126  is being used to dispense coating material  132  onto edge  110  of glass layer  108 . Equipment  126  includes computer-controlled positioner  128 , dispensing head  130 , and nozzle  132 . During operation, coating material  134  is dispensed onto edge surface  110  via nozzle  132  while positioner  128  runs head  130  around the periphery of glass layer  108 , thereby forming edge coating  136 . Equipment for dispensing material  134  may include dipping equipment, spraying equipment, ink-jet printing equipment, pad printing equipment, screen printing equipment, painting equipment, physical vapor deposition equipment, electrochemical deposition equipment, etc. 
     Edge coating  136  may be a resin, sealant, or adhesive such as a light-curable adhesive (e.g., an ultraviolet (UV) light-curable adhesive or a visible light-curable adhesive), a thermal-cure adhesive, an adhesive that is cured via environment-based curing, humidity-based curing, or low-temperature curing (e.g., curing below 50 degrees Fahrenheit), an acrylic-based coating, urethane-based adhesive, or other suitable material. As shown in  FIG. 11 , equipment  210  is used to cure material  143  and to thereby form edge protection structures  136  on edge surfaces  110  of layer  108 . Equipment  210  can include a light source (e.g., a UV light source or visible light source), a heat source (e.g., a hot air gun, a heat lamp, or other heat source), or other suitable curing equipment that can be used to cure material  134  to form coating  136 . Coating structures  136  are configured to support at least some of the portion of polarizer  54  that extends laterally beyond edges  110  of substrate layer  108 , as shown in  FIG. 11 . 
     Edge coating  136  can have any suitable color. In one suitable arrangement, edge coating  136  is an opaque color such as black. Using an black edge coating can help prevent light leakage from display layer  108  to the exterior of device  10 . This is, however, merely illustrative. If desired, material  108  may be white, may be optically clear, or may be any other suitable color. 
       FIG. 12  is a top view of layer  108  following coating of peripheral edge  110  with coating structures  136 . In the illustrative configuration of  FIG. 12 , substrate layer  108  has a rectangular footprint so that edge coating  136  has a rectangular ring shape. The rectangular shape of substrate  108  in  FIG. 12  allows substrate  108  to be used in forming rectangular displays. Displays of other shapes may be formed if desired. 
     If desired, polarizer  54  may be attached to glass substrate  108  after equipment  126  is used to apply coating material  132 . This type of configuration is shown in  FIG. 13 . With a configuration of the type shown in  FIG. 13 , lamination equipment  138  receives polarizer material  54  and glass substrate  108  after coating material  136  has been applied to edge surfaces  110  of layer  108 . Lamination equipment  138  laminates layer  54  to layer  108  to form structures  140 . 
     Edge portions of polarizer  54  and coating layer  136  may be trimmed to form a planar edge surface around the periphery of display layer  108 . A system such as system  150  of  FIG. 14  or other trimming equipment is used to trim the edges of polarizer  54  and coating  136  following attachment of polarizer  54  to substrate layer  108 . In a configuration of the type shown in  FIG. 14 , system  150  includes a camera such as camera  154  for capturing images of layers  54  and  108 . Camera  154  includes a digital image sensor that captures digital image data for processing by control unit  152 . Camera  154  preferably has sufficient resolution for capturing images of edge  110 . Layers  108  and  54  are supported by support structures  164  during digital imaging operations. Light source  165  in support structures  164  generates polarized and/or unpolarized backlight  167  for illuminating layers  108  and  54 . The use of polarized light in illuminating layers  108  and  54  can help delineate the location of edge  110  for camera  154 . 
     Data from camera  154  is analyzed by control unit  152  to determine the position of edge  110  relative to laser  160  and laser beam  162 . Laser  160  may be an infrared laser such as a carbon dioxide laser operating at a wavelength of 9.6 microns or may be a visible light laser such as a laser operating at a wavelength of approximately 532 nanometers (as examples). Control unit  152  may be one or more computers, embedded processors, networked computing equipment, online computing equipment, and/or other computing equipment for processing digital image data from camera  154  or other sensors to determine the location of edges  110  and for issuing corresponding control signals on outputs  170 ,  172 , and  174 . 
     The control signals on outputs  170 ,  172 , and  174  control the operation of computer-controlled positioners  156 ,  166 , and  158 , respectively. For example, control commands on path  170  control the operation of positioner  156 , which is used in adjusting the position of camera  154 . Control signals on path  172  are used in controlling the operation of positioner  166 , which is used in adjusting the position of support  164  (and therefore layers  108  and  54 ) relative to laser beam  162 . Control signals on line  174  are used to control positioner  158  and thereby adjust the position of laser  160  and laser beam  162  relative to edge  110 . If desired, different arrangements of positioners may be used. As an example, the position of machine vision equipment such as camera  154  may be fixed and/or positioner  158  and/or positioner  166  may be omitted. Additional positioners (e.g. to control mirrors or other optical structures that direct beam  162  onto layer  54 ) may also be used. The configuration of  FIG. 14  is shown as an example. 
     Optical structures such as lens  176  of  FIG. 15  are used to focus laser beam  162 . In the configuration of  FIG. 15 , the position of lens  176  is controlled by positioner  178 . Positioner  178  is a computer-controlled positioner that receives control signals from control unit  152  via input  180 . In response, positioner  178  positions lens  176  and therefore laser beam  162  relative to layer  54  and edge  110  ( FIG. 14 ). As shown in  FIG. 15 , lens  176  focuses laser beam  162  to produce a spot of diameter D over a length L. Outside of length L, laser beam  162  becomes unfocused and is characterized by an enlarged spot size and reduced power density. The length of L may be determined by the configuration of lens  176  (e.g., L may be 50 to 2000 microns or less than 100 microns or more than 100 microns). The diameter D may be about 60-100 microns (as an example). 
     Using polarizer trimming system  150  of  FIG. 14 , focused laser beam  162  of  FIG. 15  is applied to polarizer  54  and edge protection structure  136  to trim away excess portions of polarizer  54  and edge protection structures  136 . As shown in  FIG. 16 , edge portion  54 ′ of polarizer  54  and edge portion  136 ′ of edge protection structure  136  are removed from display layer  108  to expose a planar edge surface such as surface  214 . This ensures that that the lateral dimensions of polarizer  54  in dimensions X and Y match the respective lateral dimensions of edge structures  136 . 
     Laser beam  162  is preferably focused on the portion of polarizer  54  that lies just outside of edge  110  of glass layer  108 . As shown in  FIG. 16 , this type of configuration ensures that laser beam  162  cuts through polarizer layer  54  and edge coating  136 , rather than being focused on portions  184  of glass layer  108  inside of peripheral edge  110  and on the surface of peripheral edge  110 . Glass layer  108  can be damaged by excessive exposure to laser light resulting heating of layer  108 , so using system  150  of  FIG. 14  to ensure that laser beam  162  is focused on portions of polarizer  54  that overlap coating layer  136  rather than layer  108  avoids degrading the strength and reliability of layer  108  from exposure to laser beam  162 . 
     Following removal of excess edge portions of polarizer  54  and edge coating  136 , any portion of polarizer  54  that still overhangs edge  110  of layer  108  is supported by edge coating  136 . Edge coating  136  not only provides protection to edges  110  of layer  108  but also provides support and protection to polarizer  54 . For example, edge protection structures  136  can minimize the risk of polarizer peeling. 
     Additionally, the presence of planar edge surface  214  can minimize the border around a display that is used for trim structures, frame structures, or bezels. As shown in  FIG. 17 , a trim or frame structure such as C-shaped trim structure  216  can wrap around edge  214  (e.g., to form a clamp-like structure that wraps around edge  214  from the upper surface of polarizer layer  54  to the lower surface of layer  108 ). Trim structure  216  is interposed between the display structures of display  14  and housing  12  of device  10 . If edge coating  136  were not present, trim structure  216  would need to cover width W2 of the edge of the upper surface of polarizer  54  in order to sufficiently hide edge  110  of layer  108  from view. With the presence of edge coating  136 , however, edge  110  is sufficiently hidden from view and the width of upper portion  216 T of trim  216  can be reduced to width W1. 
     In another suitable arrangement, trim structure  216  can have an L-shaped structure that does not have an upper portion that hooks over the upper surface of polarizer  54 . This type of configuration is shown in  FIG. 18 . As shown in  FIG. 18 , upper surface  216 P of trim structure  216  is flush with the upper surface of polarizer layer  54 . If desired, upper surface  216 P of trim structure  216  can be fall below the upper surface of polarizer  54 . The arrangement of  FIG. 18  is merely illustrative. This type of arrangement minimizes the border area around a display that is used for trim or frame structures. 
     In another suitable arrangement, trim structure  216  can be omitted. This type of arrangement is shown in  FIG. 19 . As shown in  FIG. 19 , edge surface  214  formed by the edges of polarizer  54  and coating  136  abuts inner surface  12 S of housing  12  of device  10 . This type of arrangement not only minimizes the border area around a display used for trim or frame structures but also allows the components of device  10  such as display  14  to be mounted in device housing  12  more compactly. 
     If desired, edge surface  214  formed from the edges of polarizer  54  and coating structure  136  can form the outermost peripheral edge of device  10 . This type of configuration is shown in  FIG. 20 . As shown in  FIG. 20 , flush edge  214  forms an outermost peripheral edge surface of device  10 . If desired, additional layers, coatings, and/or components can be mounted to polarizer  54  (e.g., a cover layer such as a cover glass) and/or to layer  108 . Edge protection structures  136  provide sufficient protection for both display layer  108  as well as polarizer  54  such that an additional housing sidewall may not be required. 
       FIG. 21  is a flow chart of illustrative steps involved in forming display  14  and electronic device  10 . As shown in  FIG. 21 , display layers such as display layer  108  (e.g., a display layer that includes a layer of liquid crystal material sandwiched between color filter layer  56  and thin-film-transistor layer  58 ) may be formed at step  300 . The formation of display layer  108  may involve scribing and breaking glass layers such as layer  100  to form glass layers such as glass layer  108 . Edge surfaces  110  of glass layer  108  may be machined using equipment  124 . 
     Following formation of glass layer  108  at step  300 , polarizer layer  54  is attached to the upper surface of glass layer  108  using lamination equipment  138  at step  302 . Edge surfaces  110  are then treated with plasma at step  310  using equipment  200 . Following surface activation of edge surfaces  110  of layer  108 , edge surfaces  110  are coated with coating  136  at step  314 . 
     If desired, edge surfaces  110  of layer  108  can be activated with plasma  208  and subsequently coated with coating  136  prior to laminating polarizer  54  to layer  108 , as shown by steps  304 ,  312 , and  316 . Prior to laminating polarizer  54  to layer  108 , edge surfaces  110  may be coated with coating  136  without plasma surface activation, as shown by steps  306  and  316 . 
     At step  318 , laser-based or cutting-blade-based trimming techniques are used to trim the peripheral edges of polarizer  54  and coating  136  from the edges of glass layer  108 . By trimming excess polarizer and coating away, the lateral dimensions of polarizer  54  are trimmed to match the lateral dimensions of coating  136 , thereby forming flush edge  214 . 
     Substrate  108  may form a liquid crystal display cell that includes liquid crystal  52  interposed between color filter layer  56  and thin-film-transistor layer  58  of display  14  of  FIG. 5 . At step  320 , the layers of display  14  may be assembled to form display  14  of  FIG. 5  and display  14  may optionally be installed in device housing  12  of electronic device  10  with other device components. 
     The foregoing is merely illustrative and various modifications can be made by those skilled in the art without departing from the scope and spirit of the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20130611
Publication Date: 20170905
Grant Date: 20170905
Priority Date: 20121221
Inventors: GUPTA NATHAN K.
HASSAN MOHD FADZLI A.
LIN KUAN-YING
CHEN YU-CHENG
Assignee: APPLE INC
CPC Classifications: [{"code": "C03B33/074", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133351", "inventive": true, "first": true, "tree": "[]"}, {"code": "B32B2255/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "B23K26/361", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03B33/07", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03B33/0222", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03B33/076", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133528", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133351", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02F1/133528", "inventive": false, "first": false, "tree": "[]"}, {"code": "B23K26/361", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03B33/076", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03B33/0222", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B2255/00", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03B33/07", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03B33/074", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 50974247