PATENT DOCUMENT

Publication Number: US-10108222-B2
Application Number: US-201615177252-A
Country: US
Kind Code: B2

Title: Electronic device displays with holes to accommodate components

Abstract:
An electronic device may have a display. The display may be mounted in a housing and may have a window to accommodate a camera or other electrical component. The display may have multiple substrate layers. A hole may be formed in one of the substrate layers to form additional space within the housing to accommodate the electrical component. The hole may be drilled partway through a substrate layer to form an annular thinned region. The annular thinned region may be cracked to release a disk-shaped portion of the substrate layer and form the hole. A ring of sealant may surround the hole to help cushion the display substrate layers during drilling operations. Column spacer structures may be formed on a portion of a display substrate that is overlapped by the hole.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a housing; 
 a display mounted in the housing, wherein the display comprises:
 a first substrate layer, wherein the first substrate layer includes at least one metal column spacer pad; 
 a second substrate layer, wherein the first substrate layer has a hole that passes through the first substrate layer without penetrating the second substrate layer; and 
 a plurality of column spacers on the second substrate layer that are overlapped by the hole, wherein the plurality of column spacers comprise polymer, wherein at least one of the column spacers corresponds to the at least one metal column spacer pad, and wherein the plurality of column spacers include a first set of column spacers having a first spacing density and a second set of column spacers having a second spacing density that is less than the first spacing density; and 
 
 a light-based component in the housing that has a portion that protrudes into the hole. 
 
     
     
       2. The electronic device defined in  claim 1  wherein the display further comprises sealant adjacent to the hole. 
     
     
       3. The electronic device defined in  claim 2  wherein the sealant forms a ring of sealant that surrounds the hole and the column spacers. 
     
     
       4. The electronic device defined in  claim 1  wherein the column spacers in the first set of column spacers are spaced apart from each other by 25-75 microns and the column spacers in the second set of column spacers are spaced apart from each other by 75-150 microns. 
     
     
       5. The electronic device defined in  claim 4  wherein the display further comprises an opaque masking layer on the second substrate layer with an opening that is aligned with the hole, wherein the second set of column spacers has a ring shape that surrounds the opening in the opaque masking layer. 
     
     
       6. The electronic device defined in  claim 5  wherein the first set of column spacers has a ring shape that surrounds the second set of column spacers. 
     
     
       7. The electronic device defined in  claim 1  wherein the display further comprises a liquid crystal layer interposed between the first and second substrate layers, wherein the column spacers are formed from a polymer layer and wherein at least some additional column spacers that are formed from the polymer layer are located on the second substrate layer and extend into the liquid crystal layer. 
     
     
       8. The electronic device defined in  claim 7  wherein the additional column spacers include main column spacers and subspacers and wherein the column spacers that are overlapped by the hole are subspacers. 
     
     
       9. An electronic device, comprising:
 a display having a thin-film transistor layer, a color filter layer, and a liquid crystal layer interposed between the thin-film transistor layer and the color filter layer, wherein the thin-film transistor layer includes column spacer pads, wherein the display has an active area configured to display images and an inactive area, wherein the thin-film transistor layer has a hole in the inactive area that passes through the thin-film transistor layer without penetrating the color filter layer, wherein the display comprises a plurality of column spacers on the color filter layer that are overlapped by the hole and by the column spacer pads, wherein the display has a ring of sealant that surrounds the hole and that is attached to the thin-film transistor layer and the color filter layer; 
 a housing having a surface with a curved profile in a portion of the housing that is overlapped by the inactive area; and 
 a light-based component in the housing that has a portion that protrudes into the hole. 
 
     
     
       10. The electronic device defined in  claim 9  wherein the light-based component comprises a camera. 
     
     
       11. The electronic device defined in  claim 9  wherein some of the column spacers protrude into the liquid crystal layer and are surrounded by the sealant that surrounds the hole. 
     
     
       12. An electronic device, comprising:
 a housing; 
 a display in the housing, wherein the display has a first substrate layer and a second substrate layer, wherein the display has a hole that passes through the first substrate layer without penetrating the second substrate layer, wherein the display has a ring of sealant that surrounds the hole, wherein the ring of sealant is directly attached to the first substrate layer and a first surface of the second substrate layer, wherein the display comprises a mask on the second substrate layer having an opening, wherein the display comprises first and second groups of column spacers on the second substrate layer, wherein the first group of column spacers has a first spacing density corresponding to a first pitch, wherein the second group of column spacers has a second spacing density corresponding to a second pitch that is different from the first pitch, wherein the first group of column spacers is formed in a ring around the opening, wherein the second group of column spacers is formed in a ring around the first group of column spacers, and wherein each column spacer of the second group of column spacers is further from the opening than the column spacers of the first group of column spacers; and 
 an electrical component in the housing that has a portion that protrudes into the hole. 
 
     
     
       13. The electronic device defined in  claim 12  wherein the mask is an opaque masking layer and wherein the opening is aligned with the electrical component. 
     
     
       14. The electronic device defined in  claim 13  wherein the electrical component comprises a light-based component. 
     
     
       15. The electronic device defined in  claim 14  wherein the display further comprises:
 a liquid crystal layer between the first and second substrate layers, wherein some of the column spacers protrude into the liquid crystal layer and wherein some of the column spacers are overlapped by the hole and are surrounded by the sealant that surrounds the hole. 
 
     
     
       16. The electronic device defined in  claim 15  further comprising an overcoat layer that covers the opaque masking layer and the opening, wherein the overcoat layer is interposed between the column spacers that are overlapped by the hole and the opaque masking layer. 
     
     
       17. The electronic device defined in  claim 16  wherein the electrical component comprises a camera. 
     
     
       18. A method for forming a display, comprising:
 attaching a first substrate layer to a second substrate layer with adhesive, wherein the first substrate layer includes at least one metal column spacer pad and wherein the second substrate layer includes an opaque masking layer having an opening and wherein a ring of the adhesive surrounds the opening; 
 with a drilling tool, drilling an annular groove in the first substrate layer without penetrating entirely through the first substrate layer so that an annular thinned region of the first substrate layer is formed within the annular groove; 
 cracking the annular thinned region to remove a disk-shaped portion of the first substrate layer and form a hole in the first substrate layer; and 
 forming a polymer layer on the second substrate layer substrate that includes a plurality of column spacers between the first and second substrate layers in an active area of the display and that has at least one portion that is surrounded by the ring of adhesive, wherein at least one of the plurality of column spacers corresponds to the at least one metal column spacer pad, wherein the ring of adhesive overlaps the opaque masking layer, wherein the plurality of column spacers is overlapped by the hole, and wherein the plurality of column spacers include a first set of column spacers having a first spacing density and a second set of column spacers having a second spacing density that is less than the first spacing density.

Description:
This application claims the benefit of provisional patent application No. 62/263,111, filed Dec. 4, 2015, which is hereby incorporated by reference herein in its entirety. 
    
    
     FIELD 
     This relates generally to electronic devices and, more particularly, to electronic devices with displays. 
     BACKGROUND 
     Electronic devices often contain displays. For example, laptop computers, cellular telephones, tablet computers, and desktop computers may contain displays. Devices such as these may also include components such as cameras. 
     It can be challenging to design an electronic device that includes a display and a component such as a camera. If care is not taken, display bezels may be larger than desired to accommodate camera windows, cameras may be required to receive light through transparent layers of material that are thicker than desired, the thickness of a display may limit space available for mounting a camera within a device, or other undesired compromises may be made that detract from device aesthetics and device performance. 
     SUMMARY 
     An electronic device may have a display. The display may be mounted in a housing and may have a window to accommodate a camera or other electrical component. The display may have multiple substrate layers such as a thin-film transistor layer and a color filter layer. A layer of liquid crystal material may be interposed between substrate layers. 
     A hole may be formed in a first of the substrate layers to form additional space within the housing to accommodate a camera or other electrical component. An opaque masking layer on a second of the substrate layers may have an opening that forms a window in the display. The window in the display may be aligned with the camera or other electrical component. 
     The hole may be formed using drilling and breaking operations. A drilling tool may be used to drill an annular groove in the first substrate layer. A thinned annular region may be formed within the groove. The annular thinned region may be cracked to release a disk-shaped portion of the first substrate layer and thereby form the hole. A ring of sealant may surround the hole to help cushion the display substrate layers during drilling operations. Column spacer structures may be formed on a portion of a display substrate that is overlapped by the hole. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative electronic device in accordance with an embodiment. 
         FIG. 2A  is a cross-sectional side view of a portion of an illustrative electronic device with a window and an aligned light-based component such as a camera in accordance with an embodiment. 
         FIG. 2B  is a cross-sectional side view of a portion of an electronic device with a housing wall that has a curved profile, a window, and an aligned light-based component that is accommodated by an opening in a portion of a display in the device in accordance with an embodiment. 
         FIG. 3  is a cross-sectional side view of a portion of a display in accordance with an embodiment. 
         FIG. 4  is a cross-sectional side view of a display containing a partially formed hole in accordance with an embodiment. 
         FIG. 5  is a cross-sectional side view of a portion of an annular drill bit and a portion of a drilled display in accordance with an embodiment. 
         FIG. 6  is a cross-sectional side view of a display with a partially drilled hole in which a tool is being used to crack and remove a disk-shaped portion of a display layer in accordance with embodiment. 
         FIG. 7  is a cross-sectional side view of an illustrative annular drill bit with slots to facilitate coolant flow and debris removal during drilling in accordance with an embodiment. 
         FIG. 8  is a perspective view of an illustrative annular drill bit of the type shown in  FIG. 7  in accordance with an embodiment. 
         FIG. 9  is a top view of an edge portion of a display showing an illustrative sealant pattern having a ring-shaped portion that is used to surround a hole in accordance with an embodiment. 
         FIG. 10  is a cross-sectional side view of an illustrative display with features to facilitate hole formation through a subset of the layers of the display in accordance with an embodiment. 
         FIG. 11  is a flow chart of illustrative steps involved in forming holes in displays in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices may be provided with displays. A display may have an active area containing an array of pixels that is used to display images and an inactive area that is free of pixels. Circuitry and internal device components may be mounted under the inactive area. The display may have layers of material such as thin-film transistor layers, color filter layers, and optional cover glass layers. 
     A window for a light-based component may be formed in the display. For example, a window may be formed in the inactive area of the display or within the active area of the display. A light-based component may be aligned with the window. During operation, light may pass through the window. For example, a camera that is aligned with the window may receive light through the window. 
     To help accommodate a camera, other light-based components, other electrical components (sensors, buttons, integrated circuits, etc.), or other components within an electronic device, a hole may be formed in a display. For example, a hole may be formed that passes partway through the display. The hole may provide additional space within an electronic device for mounting a component. For example, a hole may be formed in alignment with a window for a camera or other light-based component and may help accommodate the component within the housing of an electronic device. 
       FIG. 1  is a perspective view of an illustrative electronic device of the type that may include a display with a hole. Electronic device  10  may be a computing device such as 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, a device embedded in eyeglasses or other equipment worn on a user&#39;s head, 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, an accessory (e.g., earbuds, a remote control, a wireless trackpad, etc.), or other electronic equipment. In the illustrative configuration of  FIG. 1 , device  10  is a portable device such as a cellular telephone, media player, tablet computer, or other portable computing device. Other configurations may be used for device  10  if desired. The example of  FIG. 1  is merely illustrative. 
     In the example of  FIG. 1 , device  10  includes display  14 . Display  14  has been mounted in housing  12 . In the  FIG. 1  arrangement, housing  12  has a planar shape. In a laptop computer or other structure with a hinge, housing  12  may have upper and lower portions that rotate with respect to each other about the hinge. In this type of arrangement, display  14  may be mounted in the upper housing and a keyboard, trackpad, and other components may be mounted in the lower housing (as an example). 
     Housing  12 , which may sometimes be referred to as an enclosure or case, may be formed of plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, etc.), other suitable materials, or a combination of any two or more of these materials. Housing  12  may be formed using a unibody configuration in which some or all of housing  12  is machined or molded as a single structure or may be formed using multiple structures (e.g., an internal frame structure, one or more structures that form exterior housing surfaces, etc.). Openings may be formed in housing  12  to form communications ports, holes for buttons, and other structures. 
     Display  14  may be a touch screen display that incorporates a layer of conductive capacitive touch sensor electrodes or other touch sensor components (e.g., resistive touch sensor components, acoustic touch sensor components, force-based touch sensor components, light-based touch sensor components, etc.) or may be a display that is not touch-sensitive. Capacitive touch sensor electrodes may be formed from an array of indium tin oxide pads or other transparent conductive structures. 
     Display  14  may have an active area AA that includes an array of pixels. The array of pixels may be formed from liquid crystal display (LCD) components, an array of electrophoretic pixels, an array of plasma display pixels, an array of organic light-emitting diode pixels or other light-emitting diode pixels, an array of electrowetting pixels, or pixels based on other display technologies. Illustrative configurations for display  14  in which display  14  is a liquid crystal display may sometimes be described herein as an example. This is merely an example. Display  14  may be any suitable type of display. 
     Display  14  may be protected using a display cover layer such as a layer of transparent glass, clear plastic, transparent ceramic, sapphire or other transparent crystalline material, or other transparent layer(s). The display cover layer may have a planar shape, a convex curved profile, a concave curved profile, a shape with planar and curved portions, a layout that includes a planar main area surrounded on one or more edges with a portion that is bent out of the plane of the planar main area, or other suitable shape. Openings may be formed in the display cover layer to accommodate button  16 , speaker ports, and other structures. If desired, the display cover layer may be omitted. For example, in a liquid crystal display with a substrate layers such as a color filter layer, thin-film transistor layer, or combined color filter and thin-film transistor layers, one or more of the substrate layers may be used as the outermost layer of display  14  in place of a display cover layer. 
     Display  14  may have an inactive border region that runs along one or more of the edges of active area AA. Inactive area IA may be free of pixels for displaying images and may overlap circuitry and other internal device structures in housing  12 . To block these structures from view by a user of device  10 , the underside of the display cover layer or other layer in display  14  that overlaps inactive area IA may be coated with an opaque masking layer in inactive area IA. The opaque masking layer may have any suitable color. 
     Openings may be formed in the opaque masking layer in inactive area IA. These openings may form windows for light-based components in device  10 . In the example of  FIG. 1 , window  20  has been formed in inactive area IA along an upper edge of display  14 . In general, windows such as window  20  may be formed in any suitable portion of display  14  (i.e., in other portions of inactive area IA) or other transparent structures in device  10 . In a laptop computer, for example, a window such as window  20  of  FIG. 1  may be located in the center of the uppermost edge of display  14  (e.g., in a configuration in which display  14  is mounted in an upper laptop housing). The configuration of  FIG. 1  is merely illustrative. 
     Window  20  may be circular, rectangular, or may have other suitable shapes. Window  20  may be aligned with a light-based component such an ambient light sensor, proximity sensor, a status indicator light, or a camera. Illustrative configurations in which a camera is aligned with window  20  may sometimes be described herein as an example. In general, however, device  10  may have any suitable number of windows  20 , windows  20  may be located in inactive area IA or in active area AA, and any suitable component may be aligned with windows such as window  20 . The use of window  20  to allow light to reach a light-based component such as a camera is merely illustrative. 
       FIG. 2A  is a cross-sectional side view of a portion of device  10  of  FIG. 1  in the vicinity of window  20  taken along line  22  of  FIG. 1  and viewed in direction  24 . As shown in  FIG. 2A , display  14  may have multiple layers such as layers  14 - 1 ,  14 - 2 , and  14 - 3 . With one illustrative configuration, layer  14 - 1  may be a thin-film transistor layer having a layer of thin-film transistor circuitry on a glass layer that forms pixel electrodes and associated pixel control circuits for a liquid crystal display, layer  14 - 2  may be a color filter layer having an array of color filter elements on a transparent layer such as a glass layer to provide display  14  with the ability to display color images, and layer  14 - 3  may be an optional protective display cover layer. If desired, layer  14 - 1  may be a color filter layer and layer  14 - 2  may be a thin-film transistor layer. Configurations in which color filter layer structures and thin-film transistor circuitry are formed on a common substrate may also be used in forming display  14 . If desired, display cover layer  14 - 3  may be omitted (e.g., in configurations in which the thickness of layers  14 - 1  and  14 - 2  is sufficient to structurally support display  14 ). Other layers may be used in forming a display such as display  14  if desired (e.g., clear substrate layers, substrate layers in organic light-emitting diode displays and other displays with light-emitting diodes, etc.). The arrangement of  FIG. 2A  is shown as an example. 
     An opening such as hole  26  may pass completely through or partly through display  14 . The presence of hole  26  may help provide additional space within the interior of housing  12  to accommodate protruding portions  28  of components such as component  30 . This allows the thickness T of device  10  to be minimized. If desired, opening  26  may be aligned with window  20 . In this type of arrangement, component  30  may be a light-based component that receives light from the exterior of device  10  through window  20  and/or that emits light that passes from the interior of device  10  to the exterior of device  10  through window  20 . Component  30  may be, for example, a camera with a digital image sensor such as sensor  32  that captures images focused receives light focused onto sensor  32  by lens  34 . 
     If desired, device  10  may have one or more non-planar surfaces. Consider, as an example, the arrangement of  FIG. 2B . As shown in  FIG. 2B , device  10  may have a planar front face  10 F on which a planar component such as display  14  is mounted. Device  10  may also have a rear face  10 R that includes non-planar rear housing wall surface  12 R of housing  12 . The rear housing wall of housing  12  may have a gradually eased curved profile or other non-planar profile near the periphery of housing  12  (e.g., in a peripheral portion of housing  12  that is overlapped by inactive area IA of display  14  and, if desired, a peripheral portion of active area AA) and may have a planar shape near the center of housing  12  (e.g., in the portion of housing  12  that is overlapped by active area AA). Opening  26  may be formed in display  14  in alignment with window  20  to help accommodate protruding portion  28  of component  30  (e.g., a camera, other light-based component, or other electrical component). The presence of opening  26  helps allow the thickness of housing  12  and therefore device  10  to be reduced near the periphery of housing  12  (e.g., to better accommodate a desired curved profile for rear housing wall surface  12 R than would otherwise be possible). In the absence of opening  26 , rear surface  12 R would be more planar and less curved at locations near peripheral edge  12 P of housing  12 . 
     Optional display cover layer  14 - 3  and display layers  14 - 1  and  14 - 2  may each be formed from a transparent material such as glass, plastic, sapphire or other crystalline material, transparent ceramic, etc. In active area AA, display  14  may contain an array of pixels for displaying images. In inactive area IA, display  14  may have an opaque masking layer that blocks internal device components from view. The opaque masking layer may be formed on one or more of the surfaces of layers such as layers  14 - 1 ,  14 - 2 , and  14 - 3 , or other display layers (e.g., polarizer layers, etc.). If desired, black polymer or opaque inorganic structures or other masking material (e.g. a part of the opaque masking layer or one or more additional layers) may be patterned to form a grid with openings that form respective pixels in display  14 . These masking structures may be formed on layer  14 - 1  and/or  14 - 2 . 
     Opening  26  may be formed by drilling entirely through display  14  (e.g., to form a through-hole), may be formed by drilling partway through display  14  in a configuration in which hole  26  ends in the middle of one of the layers of display  14 , or may be formed by forming a through-hole through one or more of the sublayers of display  14 . In the example of  FIG. 2A , hole  26 , which passes only partway through display  14 , has been formed by creating a through-hole through a single layer (layer  14 - 1 ) without forming any through-holes or partial holes through the other layers of display  14  (i.e., layers  14 - 2  and  14 - 3 ). 
     If desired, hole  26  may be formed by creating through-holes through multiple layers of display  14  while leaving one or more layers of display  14  intact. For example, hole  26  may be formed by creating through-holes through layers  14 - 1  and  14 - 2  without creating any holes in layer  14 - 3 . Configurations of the type shown in  FIG. 2A  in which hole  26  passes through layer  14 - 1  without passing through other layers such as layers  14 - 2  and  14 - 3  are sometimes described herein as an example. 
     An advantage of forming hole  26  by creating a through-hole that passes through layer  14 - 1  without forming any holes in layers  14 - 2  and  14 - 3  is that this allows layers  14 - 2  and  14 - 3  to remain optically clear and free of scratches that might otherwise impair the transmission of light through the remaining layers of display  14  in window  20 . 
     Display  14  may contain one or more rigid substrate layers such as one or more layers of glass, sapphire or other crystalline transparent material, ceramic, etc. Display  14  may also contain polarizer layers, thin-film coatings, and other layers of material. Backlight structures may be used to provide display  14  with backlight illumination. Hole  26  may be formed through one or more layers such as one or more polarizer layers, one or more rigid substrate layers, coating layer(s), and/or other layers of material in display  14 . 
     A cross-sectional side view of an illustrative display is shown in  FIG. 3 . In the example of  FIG. 3 , display  14  has first and second substrates such as respective layers  14 - 1  and  14 - 2 . Layer  14 - 1  may be, for example, a thin-film transistor layer having a layer of thin-film transistor circuitry  50  on a glass layer such as layer  48 . Layer  50  may form electrodes and pixel circuits for forming an array of pixels in active area AA of display  14 . Layer  14 - 2  may be a color filter layer. Liquid crystal layer  44  may be interposed between layers  14 - 1  and  14 - 2 . Layers  14 - 1  and  14 - 2  may be sandwiched between upper polarizer  42  and lower polarizer  40  (e.g., thin polymer polarizer films). 
     Column spacers  52  may be formed on layer  14 - 2  and/or  14 - 1  to help maintain a desired separation between display layers  14 - 1  and  14 - 2 . Column spacer structures in display  14  may be formed from metal, polymer, and/or other materials. With the illustrative configuration of  FIG. 3 , display  14  has column spacer structures formed from column spacers  52  (e.g., polymer spacers) and corresponding column spacer pads  54  (e.g., metal spacer pads). Polymer column spacers may be formed from a layer of photolithographically patterned photosensitive polymer. Column spacers  52  may have multiple heights. For example, column spacers  52  may include main column spacers of larger height H 1  and subspacer column spacers (subspacers) of smaller height H 2 . Configurations with more than two different column spacer sizes may be used, if desired. 
     Backlight unit  38  may produce backlight illumination  46  for display  14 . During operation, the pixels of display  14  create images that are viewed by users such as user  56  who are viewing display  14  in direction  58 . 
     Hole  26  may be formed by laser drilling, mechanical drilling (e.g., drilling with a drill bit), water jet drilling, scribing and breaking techniques, other techniques in which thin regions of glass or other material are broken by applying sufficient mechanical force to create stress that cracks the glass, or other suitable hole formation techniques. With one suitable arrangement, which is described herein as an example, hole  26  is formed partly using mechanical drilling and partly using mechanical stress-induced cracking techniques. 
     An illustrative system for drilling during the formation of hole  26  in display  14  is shown in  FIG. 4 . As shown in  FIG. 4 , drilling equipment such as drilling tool  60  may include a drill bit such as drill bit  64  and a drill bit rotating and positioning system such as positioner  62 . Tool  60  may use positioner  62  to position drill bit  64  in dimensions X, Y, and Z and to rotate drill bit  64  in direction  68  about rotational axis  66 . 
     Drill bit  64  may be formed from metal, ceramic, or other materials and may have particles and/or coatings to enhance drilling performance (e.g., diamond structures). Drill bit  64  may have any suitable shape. As shown in  FIG. 4 , for example, drill bit  64  may have an annular shape (e.g., the leading edge of drill bit  64  may form a ring-shaped protrusion such as annular protrusion  70 ). When drill bit  64  is lowered in direction −Z, annular protruding portion  70  of drill bit  64  will grind into layer  14 - 1  and will form a ring-shaped recess such as annular groove  72 . 
     To prevent damage to underlying layers of display  14 , drilling system  60  may drill only partway into layer  14 - 1 , thereby leaving thin undrilled annular region  74  at the bottom of groove  72 . Sealant  76  may be interposed between layers  14 - 1  and  14 - 2  and may be used to support the portions of display  14  surrounding groove  72 . Region  74  may be sufficiently thin to allow region  74  to be cracked to remove disk-shaped portion  78  of layer  14 - 1 . As an example, the thickness of region  74  may be about 5-10 microns, more than 3 microns, less than 20 microns, or other suitable thickness. 
     If desired, protrusion  70  on drill bit  64  may have a pointed shape of the type shown in  FIG. 5  to help form a sharply tapered profile for groove  72 . This helps to concentrate stress in thin region  74  at the bottom of groove  72 . 
       FIG. 6  shows how a glass breaking tool such as glass cracking system  82  may be used to crack thinned region  74 . System  82  may include a positioner such as positioner  84  that moves movable head  86 . Head  86  may be pressed in direction −Z when it is desired to induce stress in thinned annular region  74 . This forms annular crack  80 . Crack  80  may extend around the periphery of disk-shaped portion  78  and, when formed, may liberate disk  78  from the remainder of layer  14 - 1 . Head  86  may contain a vacuum suction mechanism, suction cup, or other mechanism for gripping disk  78 . After applying downward force to disk-shaped portion  78  of display layer  14 - 1  with system  82  to crack region  74  and thereby separate disk-shaped region  78  of layer  14 - 1  from the rest of layer  14 - 1 , head  86  may apply suction to disk-shaped portion  78  and may be moved in upward direction Z to remove disk-shaped portion  78  from display  14 . This leaves a circular through-hole (hole  26 ) in layer  14 - 1  without forming any holes in layer  14 - 2 . A deburring tool (e.g., a rotating bit) may be used to smooth the inner surfaces of hole  26  following removal of disk  78 . 
     If desired, tool  60  may include cooling structures. As shown in the cross-sectional side view of  FIG. 7 , for example, tool  60  may include fluid passageways  88  that allow water or other cooling liquid to flow into hole  26  and around drill bit  64  during drilling to help cool drill bit  64  and the regions of display  14  surrounding hole  26 . To facilitate fluid flow through and around drill bit  64  as drill bit  64  is rotated in direction  68  about rotational axis  66 , drill bit  64  may have fluid passageways such as slots  64 ′. Slots  64 ′ may be arranged around the periphery of protrusion  70  and may spiral outwardly from the center of drill bit  64  as shown in  FIG. 8 . Fluid flow promotion structures of other shapes may be formed in drill bit  64  if desired. The shape used for slots  64 ′ in  FIG. 8  is merely illustrative. 
     Sealant  76  may be formed from epoxy or other adhesive (e.g., ultraviolet light cured epoxy, etc.). A bead of sealant  76  may run around the periphery of display  14  between layers  14 - 1  and  14 - 2  to confine liquid crystal layer  44  within active area AA of display  14  and to hold layers  14 - 1  and  14 - 2  together. As shown in the top view of display  14  of  FIG. 9 , strips of sealant  76  may form a ring that surrounds hole  26 . The ring may have straight sides, curved sides, combinations of curved and straight edges, may have multiple concentric strips of material, may have a circular shape, hexagonal shape, rectangular shape, or other suitable shape. Sealant  76  may be located close to hole  26  (e.g., sealant  76  may be 100-300 microns from hole  26 , may be 200-600 microns from hole  26 , may be within 300 microns of hole  26 , or may be 5-300 microns from hole  26 ). This creates structural support for layers  14 - 1  and  14 - 2  in the vicinity of hole  26  that cushions and protects these layers during drilling operations by absorbing vibrations and stress. The sealant that surrounds hole  26  also helps prevent liquid crystal material  44  or other material from intruding into hole  26 . If desired, the sealant adjacent to hole  26  may partially surround hole  26  (e.g., the sealant may have a half-hexagon shape that runs around half of hole  26 , may have a segmented circular, hexagonal, or rectangular shape with gaps, etc.). Configurations in which the sealant forms a hexagonal ring or a ring of other suitable shapes (circular, rectangular, etc.) that surround hole  26  may help ensure satisfactory vibration absorption. 
     A cross-sectional side view of display  14  taken along line  94  and viewed in direction  96  of  FIG. 9  prior to formation of hole  26  is shown in  FIG. 10 . Hole  26  may be drilled through layer  14 - 1  in region  26 ′. A ring of structures or structures with other shapes may be formed from the metal layer of pad structures  54  (e.g., a ring having an opening such as opening  100  that can serve as an alignment mark for hole  26 ). When drilled, hole  26  may have a diameter D. The outer edge of region  26 ′ may be separated from sealant  76  by a gap of 200-600 microns or other suitable distance. Column spacers  52  may be formed within region  26 ′ (i.e., in a region that is overlapped by hole  26  when hole  26  is drilled) to help support waste material produced during hole drilling and hole deburring operations while protecting underlying structures on the surface of layer  14 - 2 . 
     As shown in  FIG. 10 , layer  14 - 2  may be coated with an opaque masking layer such as opaque masking layer  102 . Transparent overcoat layer  104  (e.g., a clear polymer layer) may cover masking layer  102 . In active area AA, masking layer  102  may form a black matrix with openings that are filled with color filter elements for the pixels of display  14 . In inactive area IA, black masking layer  102  may cover display  14  and may help hide internal components and sealant  76  from view by a viewer  56  when display  14  is used in device  10 . Opening  98  in layer  102  may form a light passageway for window  20 . Opening  98  may have a diameter of 2 mm, 1-3 mm, more than 0.5 mm, less than 4 mm, or other suitable size. 
     During hole formation, disk-shaped portion  78  of layer  14 - 1  may be removed from layer  14 - 1 . At least part of a camera or other component may then occupy space previously occupied by portion  78  in alignment with window  20 . For example, camera  30  may be mounted in alignment with window  20  so that some of camera  30  protrudes out of hole  26  and so that some of camera  30  is mounted within hole  26 . 
     Column spacers  52  in region  26 ′ may be subspacer column spacers or other suitable column spacers. Column spacers  52  in region  26 ′ may be formed from the same layer of photoimageable polymer that is used in forming column spacers that protrude into liquid crystal layer  44  from layer  14 - 2  in active area AA. The use of subspacers for forming the column spacer structures of  FIG. 10  may help accommodate glass bending during drilling operations. 
     The density of column spacers  52  (i.e., the pitch of column spacers  52 , which determines the spacing between adjacent spacers) may vary as a function of position within region  26 ′. In the example of  FIG. 10 , column spacers  52  include a first set of column spacers  52 - 1  and a second set of column spacers  52 - 2 . Column spacers  52 - 2  may be formed in a ring surrounding opening  98  and may have a relatively low density and high spacing (e.g., a spacer-to-spacer spacing of about 75-150 microns, more than 50 microns, less than 200 microns, etc.). The innermost of spacers  52 - 2  may be separated from the edge of opening  98  by a distance of about 175-225 microns, more than 150 microns, less than 250 microns, or other suitable distance. The ring of column spacers  52 - 2  that surrounds opening  98  may have a width (outer radius minus inner radius) of about 600-800 microns, more than 500 microns, less than 1000 microns, or other suitable width. Column spacers  52 - 1  may be formed in a ring that surrounds the ring formed from spacers  52 - 2 . Spacers  52 - 1  may be spaced 50 microns apart from each other, may be spaced 25-75 microns apart, may be spaced more than 30 microns apart, or may be spaced fewer than 60 microns apart (as examples). The width of the ring formed from spacers  52 - 1  may be about 800-1000 microns, more than 700 microns, less than 1100 microns, or other suitable width. 
     The use of different densities for column spacers  52 - 1  and  52 - 2  allows column spacers to be selectively configured either to enhance protection for layer  14 - 2  (e.g., by closely spacing column spacers  52 - 1  to help protect the coating layers on layer  14 - 2 ) or to facilitate debris removal during drilling (e.g., by spacing column spacers  52 - 2  farther apart than spacers  52 - 1  to help allow debris to be removed by vacuum suction). Configurations with smoothly varying column spacer density gradients or three or more regions of column spacers of different spacing densities (or two or more spacing densities, four or more spacing densities, etc.) may also be used. 
     Illustrative steps involved in forming a device having a display with a hole are shown in  FIG. 11 . 
     Display layers  14 - 1  and  14 - 2  and the other layers of display  14  may be fabricated and laminated together in the form of large mother glass panels. Sealant  76  may be dispensed in strips and other patterns between the mother glass panels using a needle dispensing tool or other adhesive patterning equipment. When cured, sealant  76  attaches display layers  14 - 1  and  14 - 2  together. Following singulation to form individual display panels  14 , a display panel may be loaded into a workpiece holder (step  120 ). 
     While in the workpiece holder, a thickness measurement tool such as an optical triangulation sensor that takes light readings from the top and bottom surfaces of transparent layers may be used to measure the thickness of layer  14 - 1  (step  122 ). 
     A position sensor (e.g., a position sensor with a movable pin) may then be used to locate the Z-axis position of the exposed outer surface of layer  14 - 1  (step  124 ). 
     At step  126 , drilling tool  60  may be used to drill partway through layer  14 - 1 , leaving thinned region  74  in place at the bottom of drilled annular groove  72 . The thickness and position information gathered during steps  122  and  124  may be used to accurately locate drill bit  64 . 
     At step  128 , glass breaking tool  82  may be used to crack layer  14 - 1  along thinned region  74  and may be used to remove the resulting disk-shaped portion of layer  14 - 1  (disk  78 ) from layer  14 - 1 . This forms hole  26  in layer  14 - 1  without creating any partially or fully drilled holes in layer  14 - 2 . 
     At step  130 , a vacuum suction tool or other equipment may be used to remove waste from hole  26 . Hole deburring operations may be performed at step  132  to remove any residual portions of thinned region  74  from hole  26 . Panel cleaning operations may be performed at step  134 . Display  14  may then be measured, inspected, and unloaded from the workpiece holder (step  136 ) before being assembled into device  10  (step  138 ). During the assembly operations of step  138 , a component such as component  30  may be mounted fully or partly within opening  26  in alignment with window  20  and may be interposed between housing  12  and layer  14 - 2 , as shown in  FIG. 2 . 
     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: 20160608
Publication Date: 20181023
Grant Date: 20181023
Priority Date: 20151204
Inventors: GUPTA, NATHAN K.
JINASUNDERA, SUDIRUKKUGE T.
LEE, MYUNGHUN
Assignee: APPLE INC
CPC Classifications: [{"code": "H04N23/57", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/1333", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04N23/57", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/1339", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N5/2257", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/13394", "inventive": true, "first": false, "tree": "[]"}, {"code": "H01L27/1214", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1686", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/1368", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133308", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1605", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02F1/133514", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10D86/60", "inventive": true, "first": false, "tree": "[]"}, {"code": "H10D86/40", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1686", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133308", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1637", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/1333", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133302", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1605", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06F1/1637", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1686", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F2201/56", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/133302", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/1339", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/13394", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F2201/56", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/1368", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/133514", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02F1/13396", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/13396", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02F1/13394", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 58798954