PATENT DOCUMENT

Publication Number: US-12195379-B2
Application Number: US-202117553105-A
Country: US
Kind Code: B2

Title: Forming and bonding of glass components for portable electronic devices

Abstract:
Techniques for making glass components for electronic devices are disclosed. The techniques disclosed herein can be used to modify a glass workpiece to form a three-dimensional glass component, such as a glass cover member. The techniques may involve reshaping the glass workpiece, fusing glass layers of the workpiece, or combinations of these. Glass components and electronic devices including these components are also disclosed.

Claims:
What is claimed is: 
     
       1. A method for making a glass component for an electronic device, the method comprising:
 installing a glass workpiece to an open frame comprising an upper frame component and a lower frame component, the glass workpiece defining a sheet and having a second portion positioned between the upper and the lower frame components and retained in the open frame, a first portion of the glass workpiece having an exposed first surface and an exposed second surface opposite to the exposed first surface; 
 transferring the glass workpiece retained within the open frame to a heating station; 
 at the heating station, heating the glass workpiece to a temperature greater than or equal to a softening point and less than or equal to a working point of the glass workpiece; 
 transferring the glass workpiece retained within the open frame to a molding station; 
 at the molding station, thermoforming the first portion of the glass workpiece between a cavity mold contacting the exposed first surface and a core mold contacting the exposed second surface to produce a molded glass workpiece, each of the cavity mold and the core mold heated to a temperature less than the temperature of the glass workpiece; 
 cooling the molded glass workpiece to a temperature less than a glass transition temperature of the glass workpiece; 
 removing the molded glass workpiece from the open frame; and 
 removing a peripheral portion of the molded glass workpiece to form the glass component, the peripheral portion including at least some of the second portion of the glass workpiece. 
 
     
     
       2. The method of  claim 1 , wherein:
 the glass workpiece is a sheet of aluminosilicate glass; and 
 the sheet has a thickness from 300 microns to 2 mm. 
 
     
     
       3. The method of  claim 2 , wherein:
 the cavity mold defines:
 a planar recessed surface; and 
 a wall surface extending from the planar recessed surface, the wall surface and the planar recessed surface together defining a cavity of the cavity mold; 
 
 a first region of the first portion of the glass workpiece contacts the wall surface during the thermoforming; and 
 a second region of the first portion of the glass workpiece contacts the planar recessed surface during the thermoforming. 
 
     
     
       4. The method of  claim 3 , wherein the first region of the glass workpiece is at a higher temperature than the second region of the glass workpiece. 
     
     
       5. The method of  claim 3 , wherein:
 the second portion of the glass workpiece is cooled during at least a portion of a process cycle in which the glass workpiece is thermoformed. 
 
     
     
       6. The method of  claim 2 , wherein the aluminosilicate glass is a lithium aluminosilicate glass. 
     
     
       7. The method of  claim 1 , wherein:
 the glass workpiece is clamped between the upper frame component and the lower frame component. 
 
     
     
       8. The method of  claim 7 , wherein a mechanical element clamps the glass workpiece between the upper frame component and the lower frame component. 
     
     
       9. The method of  claim 1 , wherein the glass component is a glass cover and defines an external surface of the electronic device. 
     
     
       10. The method of  claim 1 , wherein the core mold defines a protruding feature. 
     
     
       11. The method of  claim 1 , wherein the second portion of the glass workpiece moves within the open frame during the operation of producing the molded glass workpiece. 
     
     
       12. The method of  claim 11 , wherein a region of the second portion of the glass workpiece is thermoformed during the operation of producing the molded glass workpiece.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This application is a nonprovisional application of and claims the benefit of U.S. Provisional Patent Application No. 63/154,205, filed Feb. 26, 2021 and titled “Forming and Bonding of Glass Components for Portable Electronic Devices,” and of U.S. Provisional Patent Application No. 63/126,880, filed Dec. 17, 2020 and titled “Forming and Bonding of Glass Components for Portable Electronic Devices,” the disclosures of which are hereby incorporated herein by reference in their entireties. 
    
    
     FIELD 
     The described embodiments relate generally to techniques for forming and bonding glass components for electronic devices. More particularly, the present embodiments relate to techniques which allow glass workpieces to be shaped and/or bonded rapidly. 
     BACKGROUND 
     Traditional electronic devices include glass parts such as cover sheets and the like. Some glasses used for cover sheets are hard and resist scratching. However, these glasses can also have high molding and/or fusing temperatures. Therefore, mechanical techniques such as grinding and polishing have traditionally been used to shape cover sheets formed from these glasses. 
     SUMMARY 
     Techniques for making glass components for electronic devices are disclosed herein. In embodiments, the techniques disclosed herein can be used to modify a glass workpiece to form a three-dimensional glass component, such as a glass cover member. The techniques may involve reshaping the glass workpiece, fusing glass layers of the workpiece, or combinations of these. The disclosure also relates to glass components and enclosures and electronic devices including the glass components. 
     In some cases, the shape of the glass workpiece is modified using a forming technique. By the way of example, a first portion of the glass workpiece, which may be a central portion of the glass workpiece, is heated and then shaped between two mold members. A peripheral portion of the workpiece is supported by a frame which is configured to expose the first portion of the glass workpiece. The frame may also help control movement of the glass workpiece during the molding operation. The mold members may be at a lower temperature than the first portion of the glass workpiece, so that the forming technique is a non-isothermal forming technique. 
     Such a non-isothermal forming technique can produce molded glass components more rapidly than an isothermal forming technique in which the glass workpiece and the mold members are gradually brought to the same temperature. The non-isothermal forming techniques described herein can be especially useful for molding glasses which become soft enough to be molded only at relatively high temperatures. For example, the forming techniques disclosed herein can be useful for aluminosilicate glasses and borosilicate glasses. 
     In additional cases, the glass workpiece is modified using a bonding technique. By the way of example, at least a portion of a workpiece comprising an assembly of glass layers is heated and then pressed between a first tool-piece and a second tool-piece to fuse the glass layers. A peripheral portion of the workpiece is supported by an open frame which is configured to allow the first tool-piece and the second tool-piece to contact the workpiece. The tool-pieces may be at a lower temperature than the heated portion of the glass workpiece, so that the bonding technique is a non-isothermal bonding technique. Such a non-isothermal bonding technique can produce fused glass components more rapidly than an isothermal bonding technique in which the glass workpiece and the mold tool-piece are gradually brought to the same temperature. Therefore, the non-isothermal bonding techniques described herein can be especially useful for bonding glasses which become fusible only at relatively high temperatures. 
     The disclosure provides a method for making a glass component for an electronic device. The method comprises installing a glass workpiece to an open frame, the glass workpiece retained in the open frame by a peripheral portion of the glass workpiece and having an exposed first surface and an exposed second surface opposite to the exposed first surface when the glass workpiece is installed in the open frame. The method further comprises heating the glass workpiece to a temperature greater than or equal to a softening point and less than or equal to a working point of the glass workpiece. The method additionally comprises thermoforming a first portion of the glass workpiece between a cavity mold contacting the exposed first surface and a core mold contacting the exposed second surface to produce a molded glass workpiece, each of the cavity mold and the core mold heated to a temperature less than the temperature of the glass workpiece. The method also comprises cooling the molded glass workpiece to a temperature less than a glass transition temperature of the glass workpiece, removing the molded glass workpiece from the open frame, and at least partially removing a second portion of the molded glass workpiece to form the glass component, the second portion including at least some of the peripheral portion. 
     The disclosure also provides a method for making a glass component for an electronic device, the method comprising placing a workpiece in an open frame, the workpiece comprising an assembly of glass layers. The method further comprises heating at least a portion of the workpiece to a temperature greater than or equal to an annealing point and less than or equal to a softening point of the glass layers of the assembly. The method also comprises fusing the assembly of the glass layers to form the glass component by pressing the workpiece between a first tool-piece and a second tool-piece, each of the first tool-piece and the second tool-piece heated to a temperature less than the temperature of the workpiece. The method additionally comprises cooling the glass component to a temperature less than or equal to a glass transition temperature of the glass component and removing the glass component from the open frame. 
     In addition, the disclosure provides an electronic device comprising an enclosure comprising a rear glass cover member and a sensor assembly coupled to an interior surface of the rear glass cover member and comprising a sensor. The rear glass cover member comprises a first glass layer defining a base region of an exterior surface of the rear glass cover member and a second glass layer fused to the first glass layer and defining at least a portion of a protruding feature, the portion defining a plateau region of the protruding feature. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like elements. 
         FIG.  1 A  depicts an example electronic device including a glass component. 
         FIG.  1 B  depicts another example electronic device. 
         FIG.  2    shows a simplified cross-section view of an example glass component made using a forming technique. 
         FIG.  3 A  shows a simplified partial cross-section view of another example glass component. 
         FIG.  3 B  shows a simplified partial cross-section view of another example glass component. 
         FIG.  4    shows a flowchart of a forming process for making a glass component. 
         FIG.  5    schematically shows a series of stages in a process for forming a glass component. 
         FIG.  6 A  schematically shows an example of an operation of heating a glass workpiece. 
         FIG.  6 B  schematically shows another example of an operation of heating a glass workpiece. 
         FIG.  7 A  schematically shows an example heating pattern for a glass workpiece. 
         FIG.  7 B  schematically shows another example heating pattern for a glass workpiece. 
         FIG.  8    shows an exploded view of a frame supporting a glass workpiece and core and cavity molds. 
         FIG.  9    shows a partial cross-section view of an example glass component made using a bonding technique. 
         FIG.  10    shows a partial cross-section view of another example glass component made using a bonding technique. 
         FIG.  11    shows a flow chart of a bonding process for making a glass component. 
         FIG.  12 A  shows an example of glass layers used to form a workpiece and  FIG.  12 B  shows the glass layers assembled to form the workpiece. 
         FIG.  12 C  shows the workpiece of  FIG.  12 B  placed into an open frame. 
         FIG.  13 A  shows an additional example of glass layers used to form a workpiece and  FIG.  13 B  shows the glass layers assembled to form the workpiece. 
         FIG.  13 C  shows the workpiece of  FIG.  13 B  placed into an open frame. 
         FIGS.  14 A,  14 B, and  14 C  show examples of heating patterns for heating a workpiece including an assembly of glass layers. 
         FIG.  15    shows an example of an operation of fusing a workpiece including an assembly of glass layers. 
         FIG.  16    shows an example heating pattern for a process which combines bonding and forming techniques. 
         FIG.  17    shows a block diagram of a sample electronic device that can incorporate a glass component. 
     
    
    
     The use of cross-hatching or shading in the accompanying figures is generally provided to clarify the boundaries between adjacent elements and also to facilitate legibility of the figures. Accordingly, neither the presence nor the absence of cross-hatching or shading conveys or indicates any preference or requirement for particular materials, material properties, element proportions, element dimensions, commonalities of similarly illustrated elements, or any other characteristic, attribute, or property for any element illustrated in the accompanying figures. 
     Additionally, it should be understood that the proportions and dimensions (either relative or absolute) of the various features and elements (and collections and groupings thereof) and the boundaries, separations, and positional relationships presented therebetween, are provided in the accompanying figures merely to facilitate an understanding of the various embodiments described herein and, accordingly, may not necessarily be presented or illustrated to scale, and are not intended to indicate any preference or requirement for an illustrated embodiment to the exclusion of embodiments described with reference thereto. 
     DETAILED DESCRIPTION 
     Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred implementation. To the contrary, the described embodiments are intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the disclosure and as defined by the appended claims. 
     The following disclosure relates to techniques for making glass components for electronic devices. In embodiments, the techniques disclosed herein can be used to modify a glass workpiece to form a three-dimensional glass component, such as a glass cover member. The techniques may involve reshaping the glass workpiece, fusing glass layers of the workpiece, or combinations of these. 
     In some cases, the shape of the glass workpiece is modified using a forming technique, which may also be referred to herein as a thermoforming technique, a molding technique, a reforming technique, a hot stamping technique, or a (re)shaping technique. By the way of example, a first portion of the glass workpiece, which may be a central portion of the glass workpiece, is heated and then shaped between two mold members. A second portion of the glass workpiece (e.g., a peripheral portion) is supported by a frame which is configured to expose the first portion of the glass workpiece. The frame may also help control movement of the glass workpiece during the forming operation. The mold members may be at a lower temperature than the first portion of the glass workpiece, so that the forming technique is a non-isothermal forming technique. 
     In additional cases, the glass workpiece is modified using a bonding technique. By the way of example, at least a portion of a workpiece comprising an assembly of glass layers is heated and then pressed between a first tool-piece and a second tool-piece to bond the glass layers. A peripheral portion of the workpiece is supported by an open frame which is configured to allow the first tool-piece and the second tool-piece to contact the workpiece. The tool-pieces may be at a lower temperature than the heated portion of the glass workpiece, so that the bonding technique is a non-isothermal bonding technique. 
     The non-isothermal forming and/or bonding techniques described herein can produce glass components more rapidly than isothermal forming and bonding techniques in which the glass workpiece and the mold members and/or tool pieces are gradually brought to the same temperature. The non-isothermal forming techniques and/or bonding techniques described herein can be especially useful for forming glasses which become soft enough to be molded only at relatively high temperatures. For example, the techniques disclosed herein can be useful for aluminosilicate glasses and borosilicate glasses. 
     The disclosure also relates to glass components and enclosures and electronic devices including the glass components. Although the following description provides examples of glass components which can be used as cover members for electronic devices, in additional examples the techniques described herein can be used to produce other types of glass components, such as other types of glass enclosure components. 
     These and other embodiments are discussed below with reference to  FIGS.  1 A- 17   . However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these figures is for explanatory purposes only and should not be construed as limiting. 
       FIG.  1 A  depicts an example electronic device  100 . In embodiments, the electronic device  100  has an enclosure  110  that includes a glass cover member or other glass component produced by a technique as described herein. In some embodiments, the electronic device  100  may be a digital media player, a portable media player, and/or a home control device. In additional embodiments, the electronic device  100  may be a computing device (e.g., a desktop, notebook, laptop, or tablet computing device), a mobile telephone (also referred to as a mobile phone), an input device, or another type of portable electronic device. As shown in  FIG.  1 A , the electronic device  100  has a form factor in which the height of the device is greater than both the width and the length of the top face. In addition, the width and the length of the top face of the electronic device  100  are depicted as similar in size. The form factor shown in the example of  FIG.  1 A  is exemplary rather than limiting and in additional examples the height may be less than the width and/or the length, the width and the length of the top face may differ, or both. 
     As shown in  FIG.  1 A , the electronic device  100  comprises an enclosure  110  including an enclosure component  112  and a cover  122 . The cover  122  may define at least a portion of a front surface  102  of the electronic device and may be referred to as a front cover. In some examples, the enclosure further includes another cover which defines at least a portion of a rear surface  104  of the electronic device and which may be referred to as a rear cover. In embodiments, the cover  122  includes a glass component produced by a technique as described herein. In additional examples, a cover may define another external surface of the electronic device, such as a rear surface, a side surface, or two or more of front, rear, and side surfaces of the electronic device. 
     In some embodiments, a cover of the electronic device  100 , such as the cover  122 , is three-dimensional (e.g., non-planar) or defines a contoured profile. For example, the cover  122  may define a peripheral portion that is not coplanar with respect to a central portion. An example of a three-dimensional shape defining a generally planar central portion and a peripheral portion extending out of the plane defined by the central portion is shown in  FIG.  2   . The peripheral portion may, for example, define a side wall of an electronic device enclosure, while the central portion defines a front surface (which may define a transparent window that overlies a display). As an additional example, a cover may define a surface protrusion (an example of which is shown in  FIG.  1 B ), a surface recess, and/or one or more curved surfaces. A glass component such as a glass cover member  132  may be shaped similarly to its respective cover. 
     In the example of  FIG.  1 A , the cover  122  is positioned over a display  144  that is at least partially enclosed or surrounded by the enclosure component  112  of the enclosure  110 . The cover  122  may define a transparent region for viewing the display. Alternately or additionally, the cover  122  may be integrated with or coupled to a touch sensor that is configured to detect or estimate a location of a touch along the exterior surface of the cover  122 . The touch sensor may include an array of capacitive electrodes that are positioned below the cover  122  and, in some instances, may be integrated with the display. In additional examples, the cover  122  may be integrated with or coupled to an electronic device component which provides an alternate or an additional functional characteristic. Capacitive and/or other functional characteristics may be associated with planar and/or non-planar regions of the cover  122 . The additional description of displays and sensors provided with respect to  FIG.  17    is generally applicable herein and is not repeated here. 
     The cover  122  includes a cover member  132 , which may be referred to as a front cover member. The cover member  132  may extend laterally across the cover  122 , such as substantially across the width and the length of the cover  122 . The cover member  132  may have a thickness from about 0.3 mm to about 0.75 mm or from about 0.5 mm to about 1 mm. In some embodiments the cover member  132  is a glass component (a glass cover member), which may be produced by a technique as described herein. The additional description of glass components provided herein, including the description provided with respect to  FIGS.  2 ,  3 A,  3 B,  9 , and  10   , is generally applicable herein. In additional embodiments, the cover member  132  may be formed of one or more materials other than glass, and in some cases may be a glass ceramic cover member. In some embodiments, the cover  122  may define one or more holes extending though its thickness, with the hole positioned over another device component such as a microphone, speaker, an optical camera or sensor component, or the like. 
     The cover  122  may include one or more coatings applied to the cover member. For example, an anti-reflection and/or smudge-resistant coating may be applied to an exterior surface of the cover member. As an additional example, a coating designed to produce a visual effect, such as an opaque mask coating, may be applied to an interior surface of the cover member. In a further example, the cover  122  may include a laminate material (e.g., in sheet form) applied along an interior surface of the cover  122  to provide structural support/reinforcement, an electrical function, a thermal function, and/or a visual effect. The laminate material may conform to a three-dimensional portion of the cover. 
     As shown in  FIG.  1 A , the enclosure  110  further includes an enclosure member  112 , which for simplicity may also be referred to herein as a housing. The cover  122  may be coupled to the enclosure member  112 . For example, the cover  122  may be coupled to the enclosure member with an adhesive, a fastener, an engagement feature, or a combination thereof. 
     In embodiments, the enclosure member  112  at least partially defines a side surface  106  of the electronic device  100 . In the example of  FIG.  1 A , the enclosure member  112  defines all four sides of the electronic device  100 . The enclosure member  112  of  FIG.  1 A  also defines corner regions  108 .  FIG.  1 A  includes vertical lines to indicate approximate boundaries of the corner regions  108 . One or more of the corner regions may define a compound curvature. In additional embodiments, an enclosure member  112  may be positioned internal to the electronic device  100  and one or more of a front cover  122  or a rear cover may define all or most of the side surfaces of the electronic device. In the example of  FIG.  1 A , the electronic device  100  includes an input device  152 , which may be a button or any other input device described with respect to  FIG.  17   . The enclosure component  112  may define an opening to accommodate the input device. In additional examples, an enclosure component may define one or more openings in a side surface to allow (audio) input or output from a device component such as a microphone or speaker, to provide a window for transmission and/or receipt of a wireless signal, and/or to accommodate an electrical port or connection. 
     In some embodiments, the enclosure component  112  may be formed from a single material, and may be a monolithic component. For example, the enclosure component  112  may be formed from a glass material, a metal material, a ceramic material, a glass ceramic material, or a polymer material. In some cases, the enclosure component is a glass component as described herein. In additional embodiments, an enclosure component may include multiple members. For example, the enclosure component may include one or more metal members, one or more glass members, or one or more glass ceramic members. In some cases, one or more of the glass members may be a glass component as described herein. In some cases, an enclosure member is formed from a series of metal segments that are separated by dielectric segments that provide electrical isolation between adjacent metal segments. For example, a dielectric segment may be provided between a pair of adjacent metal segments. One or more of the metal segments may be coupled to internal circuitry of the electronic device  100  and may function as an antenna for sending and receiving wireless communication. The dielectric segments may be formed from one or more dielectric materials such as a polymer, a glass, or a ceramic material. As referred to herein, a component or member formed from a particular material, such as a glass or a metal material, may also include a relatively thin coating of a different material along one or more surfaces, such as an anodization layer, a physical vapor deposited coating, a paint coating, a primer coating (which may include a coupling agent), or the like. 
     In addition to a display and/or a touch screen, the electronic device  100  may include additional components. These additional components may comprise one or more of a processing unit, control circuitry, memory, an input/output device, a power source (e.g., a battery), a charging assembly (e.g., a wireless charging assembly), a network communication interface, an accessory, a sensor, or another component that is part of a wireless communication system (e.g., an antenna, a transmitter, receiver, transceiver, or the like). Components of a sample electronic device are discussed in more detail below with respect to  FIG.  17    and the description provided with respect to  FIG.  17    is generally applicable herein. 
       FIG.  1 B  shows another example of an electronic device  101 . In embodiments, the electronic device  101  has an enclosure  111  that includes a glass cover member or other glass component produced by a technique as described herein. The electronic device  101  may be any of the electronic devices previously described with respect to the electronic device  100  and may have any of the form factors previously described with respect to that device. 
     As shown in  FIG.  1 B , the enclosure  111  includes a cover  123 . The cover  123  includes a cover member  133 . The cover member  133  may define at least a portion of a front surface  103  of the electronic device and may be referred to as a front cover member. The cover member  133  may extend laterally across the cover  123 , such as substantially across the width and the length of the cover  123 . In some embodiments the cover member  133  is a glass component (a glass cover member), which may be produced by a technique as described herein. In additional embodiments, the cover member  133  may be formed of one or more materials other than glass, and in some cases may be a glass ceramic cover member. The glass cover member  133  may be shaped similarly to the cover  123 . 
     In the example of  FIG.  1 B , the cover  123  defines a protruding portion  127  which protrudes with respect to another portion  126  of the cover. The protruding portion  127  may also be referred to herein as a protruding feature or simply as a feature. More generally, a glass component such as the cover member  133  may define one or more features which vary in elevation with respect to a neighboring portion or region of the glass component. A feature which is formed to a different elevation than a neighboring portion of the glass component may define a protrusion or a recess in some embodiments. In some cases, a device component such as a sensor assembly, a camera assembly, and the like may be provided under a protruding feature. The size of the protruding portion  127  may depend at least in part on the size of a device component underlying the protruding feature. In some embodiments, a lateral dimension (e.g., a width) of the protruding feature may be from about 2 mm to about 10 mm, from about 5 mm to about 30 mm, from about 10 mm to about 20 mm, or from about 15 mm to 30 mm. 
     In the example of  FIG.  1 B , the protruding feature  127  is shown as generally curved or rounded in shape. However, this example is not limiting and in other examples (e.g.,  FIG.  3 B ), a protruding feature may define a substantially plateau-shaped top. The plateau-shaped top may be substantially parallel to an exterior surface defined by an adjacent portion of the cover. The amount of protrusion or offset between the top of the protruding portion  127  and the exterior surface of the adjacent portion of the cover may be from about 0.5 mm to about 1.5 mm or from about 0.75 mm to about 2 mm. 
     When the glass cover member  133  is shaped similarly to the cover  123 , the glass cover member  133  may also define a protruding feature. Non-limiting examples of glass cover members defining protruding features are shown in the cross-section views of  FIGS.  3 A,  3 B,  9   , and  10 . 
     In some examples, a cover member  133  that defines a protruding feature has substantially the same thickness as a neighboring portion of the cover member. In some cases, the cover member  133  is produced by reshaping a glass workpiece of substantially uniform thickness to form a protruding feature. As shown in the cross-sectional view of  FIGS.  3 A and  3 B , the resulting protruding feature may be convex on the exterior and concave on the interior of the cover member. In examples, the thickness of the cover member may be greater than about 0.3 mm and less than about 0.75 mm or greater than about 0.5 mm and less than about 1 mm in both portion  127  and portion  126  of the cover  123 . 
     In additional examples, the cover member  133  varies in thickness. The cover member  133  may have a greater thickness in a protruding portion than in an adjacent portion as shown in the cross-sectional views of  FIGS.  9  and  10   . In some cases, the cover member  133  is at least partly produced by bonding multiple glass layers, and differences in the number of glass layers produce differences in the thickness of the cover member  133 , as shown in the example of  FIGS.  12 A through  12 C . In embodiments, the cover member  133  may have a thickness in the protruding portion  127  that is at least 10%, 25%, or 50% and up to about 250% greater than a thickness of the cover member in the portion  126  of the cover  123 . In some cases, the thickness of the thicker portion of the cover  123  (including the protruding feature) is greater than about 1 mm and less than or equal to about 2 mm or about 2.5 mm. The thickness of the portion  126  of the cover  123  may be greater than about 0.3 mm and less than about 0.75 mm or greater than about 0.5 mm and less than about 1 mm. 
     In some embodiments, the cover  123  may define one or more holes extending though its thickness, also referred to herein as through-holes. The one or more holes may facilitate positioning of one or more device components, such as a speaker or an optical module of a camera assembly or sensor assembly. In some cases, a hole may be formed into the protruding feature  127  and a device component may extend at least partially into the hole in the protruding feature. By the way of example, the electronic device may include one or more optical modules selected from a camera modules, an optical sensor module, an illumination module, and a (non-optical) sensor. In some examples, a window may be provided over the hole to protect the underlying device component. When the glass cover member  133  is shaped similarly to the cover  123 , the glass cover member may also define one or more through-holes, non-limiting examples of which are shown in the examples of  FIGS.  3 B,  9 , and  10   . 
     In some cases, the cover  123  may be integrated with or coupled to a touch sensor or another electronic device component which provides a functional characteristic to the cover. The cover  123  may include one or more coatings applied to the cover member and these coatings may be similar to the coatings previously described with respect to the cover  122 . In some examples, the cover  123  may include a laminate material applied along an interior surface of the cover  123  in a similar fashion as described with respect to  FIG.  1 A . 
     The enclosure  111  of the electronic device  101  also includes an enclosure member  113 . The enclosure member  113  at least partially defines a side surface  107  of the electronic device  100 . In the example of  FIG.  1 B , the enclosure member  113  defines all four sides of the electronic device  101 . The enclosure member  113  of  FIG.  1 B  also defines corner regions  109 . The enclosure member may be similar in construction and materials to the enclosure member  112  and those details are not repeated here. 
     In addition to a display and a camera assembly, the electronic device  101  may include additional components. For example, the electronic device may include one or more sensor assemblies and/or camera assemblies. As additional examples, the electronic device may comprise one or more of a processing unit, control circuitry, memory, an input/output device, a power source (e.g., a battery), a charging assembly (e.g., a wireless charging assembly), a network communication interface, an accessory, and a sensor. Components of a sample electronic device are discussed in more detail below with respect to  FIG.  17    and the description provided with respect to  FIG.  17    is generally applicable herein. 
       FIG.  2    shows a simplified cross-section view of an example glass component  232 . The glass component  232  defines a three-dimensional shape and may be an example of the cover member  132  of  FIG.  1 A . The cross-section view may be along A-A in  FIG.  1 A . The three-dimensional shape of the glass component  232  may be referred to as a “dish” shape. 
     The glass component  232  may be described as defining a generally planar central portion and a peripheral portion extending from the generally planar central portion. As shown in  FIG.  2   , the glass component  232  includes a central portion  292  and a peripheral portion  294  which extends out of the plane defined by the central portion  292 . The central portion  292  and the peripheral portion  294  are contiguous. The peripheral portion  294  shown in  FIG.  2    defines an angle with respect to the generally planar central portion  292  (as seen in the cross-section view). The peripheral portion  294  may therefore be referred to herein as an angled portion. In the example of  FIG.  2   , the peripheral portion  294  defines an obtuse angle with respect to the generally planar central portion, but this example is not limiting, and, in some embodiments, a peripheral portion may define a ninety-degree angle or an acute angle with respect to a central portion. The three-dimensional shape shown in  FIG.  2    is exemplary rather than limiting and the techniques described herein can be used to produce a variety of three-dimensional shapes, including shapes where the central portion is curved rather than planar. 
     In the example of  FIG.  2   , the glass component  232  defines interior and exterior surfaces ( 242 ,  244 ) which are generally planar in the central portion  292  of the cover and curved in the peripheral portion  294  of the cover. As shown, the interior and exterior surfaces in the peripheral portion generally curve towards the interior of the electronic device. In other words, the curve defined by the interior and exterior surfaces in the peripheral portion is concave with respect to an interior of the electronic device. As shown in  FIG.  2   , the central portion  292  includes the central exterior surface  244   a  and the central interior surface  242   a . The peripheral portion  294  includes the peripheral exterior surface  244   b , the transitional interior surface  242   b , and the peripheral interior surface  242   c . The peripheral interior surface  242   c  is offset from the central interior surface  242   a ; the transitional interior surface  242   b  provides a transition between the peripheral interior surface  242   c  and the central interior surface  242   a . The curvature and/or the curve length of the peripheral exterior surface  244   b  and of the transitional interior surface  242   b  is not limited to the example of  FIG.  2    and the curvature and/or the curve length may be larger or smaller than that shown. 
     In some cases, the glass component has a smooth surface. When the roughness of the glass component is measured by an arithmetical mean height (e.g., R a  or S a ), one or more surfaces of the glass component may have a surface roughness greater than zero and less than about 250 nm, 150 nm, 100 nm, 50 nm, 25 nm, or 10 nm. The glass component may also have a transmittance and clarity sufficiently high enough that a high resolution graphic produced by a display is not distorted. 
     Typically, the glass component is formed from a silica-based glass material. The glass material may have a network structure, such as a silicate-based network structure. As referred to herein, a “glass cover member,” a “glass component,” a “glass workpiece,” a “glass sheet,” a “glass layer,” and/or a “glass piece” may include some relatively small amount of impurities or crystalline material, such as 1% or less, 2% or less, or 5% or less by weight of the member. 
     In some embodiments, the glass material includes an aluminosilicate glass. As used herein, an aluminosilicate glass includes the elements aluminum, silicon, and oxygen, but may further include other elements. Typically, the glass material includes an ion-exchangeable glass material, such as an alkali metal aluminosilicate glass (e.g., a lithium aluminosilicate glass). An ion-exchangeable aluminosilicate glass may include monovalent or divalent ions that compensate for charges due to replacement of silicon ions by aluminum ions. Suitable monovalent ions include, but are not limited to, alkali metal ions such as Li + , Na + , or K + . Suitable divalent ions include alkaline earth ions such as Ca 2+  or Mg 2+ . In some embodiments, the glass material includes a crystallizable glass. 
       FIG.  3 A  shows a simplified partial cross-section view of an example glass component  333 . The glass component  333  defines a three-dimensional shape which includes a protruding feature  327 . The glass component  333  may be an example of the glass cover member  133  described with respect to  FIG.  1 B  and the cross-section view may be along B-B in  FIG.  1 B . The shape of the protruding feature shown in  FIG.  3 A  is exemplary rather than limiting and the techniques described herein can be used to produce a variety of three-dimensional shapes. 
     The protruding portion  327  protrudes with respect to an adjacent portion  326  of the glass component  333 . As shown in  FIG.  3 A , the protruding portion  327  defines a top  346 . Each of an exterior surface  344  and an interior surface  342  of the glass component  333  defines a curved contour at the protruding portion  327 . The exterior surface  344  is convexly curved and the interior surface  342  is concavely curved at the protruding portion  327 . 
     In the example of  FIG.  3 A , the protruding portion  327  has about the same thickness as an adjacent portion  326  of the glass component. The example of  FIG.  3 A  is not limiting, and in additional examples, a protruding portion may be thicker or thinner than an adjacent portion of the glass component.  FIGS.  9  and  10    show examples of glass components having thicker protruding portions. 
       FIG.  3 B  shows a simplified partial cross-section view of another example glass component  334 . The glass component  334  defines a three-dimensional shape which includes a protruding feature  336 . The glass component  334  may be an example of the cover member  133  of  FIG.  1 B  and the cross-section view may be along B-B in  FIG.  1 B . For simplicity, only one through-hole  362  is shown in  FIG.  3 B , but the protruding feature may include additional through-holes as previously described with respect to  FIG.  1 B . The shape of the protruding feature shown in  FIG.  3 B  is exemplary rather than limiting and the techniques described herein can be used to produce a variety of three-dimensional shapes. 
     The glass component  334  defines an exterior surface  344  and an interior surface  342 . The glass component also includes a base portion  339  which defines a base region  349  of the exterior surface  344 . The glass component  334  also defines a protruding feature  336  which protrudes with respect to the base region  349  and defines a top region  347  and a side region  348  of the protruding feature  336 . As shown in cross-section view of  FIG.  3 B , the protruding feature  336  defines a convex exterior surface and a concave interior surface. The thickness of the base portion  339  of the glass component  334  is about the same as the thickness of the protruding feature  336 . In embodiments, the cover member  334  is produced by reshaping a glass workpiece of substantially uniform thickness to form the protruding feature  336 . 
     As previously discussed, the present disclosure provides forming techniques, which may be non-isothermal forming techniques.  FIG.  4    shows a flow chart of an example process  400  for making a glass component by forming a glass workpiece. The process  400  may be performed at several stations, as schematically shown in  FIG.  5   . The time spent at each station may be limited to more rapidly produce the glass component. For example, the time spent at each station may be 30 seconds or less, 20 seconds or less, from 2 seconds to 30 seconds, or from 5 seconds to 20 seconds. 
     In some cases, the glass workpiece (which may also be referred to herein as a blank or a preform) may be a sheet of glass which is substantially flat and of substantially uniform thickness. In some examples the glass workpiece may have a thickness from about 300 microns to about 2 mm, from about 300 microns to about 1 mm, from about 0.3 mm to about 0.75 mm, from about 0.5 mm and to about 1 mm, or from about 0.5 mm to about 1.5 mm. In additional cases, the glass workpiece may have a non-uniform thickness and/or may have a shape other than a flat shape. For example, the shape of the glass workpiece may be engineered to facilitate the forming process. The glass workpiece may have lateral dimensions larger than those of the glass component to facilitate its placement in a frame, as described in more detail below. The glass workpiece may be formed from any of the glass materials previously described with respect to  FIG.  2   . In some examples the glass workpiece may be cleaned and/or may be treated with one or more surface treatments such as etching and plasma treatment prior to placement in the frame. The glass workpiece may have a smooth surface finish in order to provide good contact between the glass workpiece and the mold surfaces and/or to minimize polishing in the finishing operation(s)  412 . As examples, the glass workpiece may have a surface roughness (e.g., R a  or S a ) greater than zero and less than about 250 nm, 150 nm, 100 nm, 50 nm, 25 nm, or 10 nm. 
     The process  400  includes an operation  402  of placing the glass workpiece in a frame. The frame typically forms an outline around a peripheral portion of the glass workpiece and is open over a central portion of the glass workpiece as shown in  FIG.  8   . The frame may be open over both faces of the central portion of the glass workpiece and may therefore be referred to herein as an open frame. The open frame may expose a portion of the glass workpiece to be molded, which may also be referred to herein as a central portion of the glass workpiece. The frame typically supports the peripheral portion of the glass workpiece. The frame carries the glass workpiece through multiple operations of the process  400 , as schematically shown in  FIG.  5   . 
     In some cases, the frame includes two components, and the glass workpiece is placed between these two components as shown in the examples of  FIGS.  6 A,  6 B, and  8   . This type of frame may also be referred to herein as a sandwich frame. In additional cases, the frame may be formed of a single member which forms a tray which supports the glass workpiece. Portions of a frame or frame component which face the glass workpiece may also be referred to herein as a face of the frame or frame component. 
     When the glass workpiece is held horizontally, the frame may include an upper frame component and a lower frame component. In some embodiments, the sandwich frame constrains movement of the peripheral portion of the glass workpiece. The movement (e.g., float) may be in directions parallel to faces of the frame (referred to as the x and y directions) and/or in directions perpendicular to the faces of the frame (referred to as the z direction). In some cases where the glass workpiece moves within the frame during the forming process, some of the peripheral portion positioned within the frame prior to the forming process may be drawn into contact with the cavity mold and the core mold during the forming process. Therefore, the size of the exposed central portion and the size of the peripheral portion within the frame may change during the forming process. As examples, the frame may control movement of the glass workpiece due to the weight of an upper frame component sitting on the glass and/or due to application of pressure to compress the two frame components against the glass workpiece. Pressure may be applied by mechanical elements such as springs, cam-locks, clamp bolts at a prescribed torque, or the like. Additional compression forces may be generated by expansion of the frame and/or the glass materials during heating. 
     The frame is typically configured to withstand elevated temperatures. In cases where the frame experiences significant heating during the process  400 , the members of the frame may be formed from one or more materials such as high purity chromium (e.g., a purity of a least 99.95%), noble metals (e.g., Pt, Rd, Ir, or alloys thereof such as Pt—Ir), or ceramic materials such as tungsten carbide, alumina, zirconia, and the like. For example, members of the frame may be formed from bulk chromium or ceramic materials. In some cases, noble metal or ceramic coatings may be applied to these bulk chromium or ceramic members or to members made from less temperature sensitive metals or alloys. In other cases where the frame is somewhat shielded from heating during the process  400 , the members of the frame can be formed from other materials such as nickel-based superalloys such as INCONEL® or STELLITE® alloys. 
     The process  400  also includes an operation  404  of heating the glass workpiece. The operation  404  may include one or more heating stages. The number of heating stages may depend on the composition and/or shape of the glass component.  FIG.  5    schematically illustrates a process which includes multiple heating stages ( 504 ,  506 , and  508 ) prior to a forming operation. In some embodiments, at least a portion of the glass workpiece is heated to a temperature high enough to soften it for the forming operation  406 . The operation  404  may take place in an air atmosphere or in a vacuum or inert gas atmosphere (e.g., nitrogen, argon, and mixtures of these). 
     The glass workpiece may be heated by a variety of methods. In some cases, the glass workpiece may be heated by radiation and/or conduction of heat. In some examples a horizontal glass workpiece may be heated from above and below with a pair of heaters, as schematically illustrated in  FIGS.  6 A and  6 B . The heaters may be infrared heaters. In some cases, the heaters may include a susceptor that is inductively heated. In additional examples, the glass workpiece may be heated using a laser, a direct flame, or by combinations of one or more heating methods. 
     The operation  404  may heat an entirety of the glass workpiece or may locally heat the glass workpiece. In some cases, an entire central portion of the glass workpiece may be heated, as shown schematically in  FIG.  6 A . In additional cases, the heating may be concentrated in portions of the glass workpiece where the most deformation and/or reshaping is to occur.  FIG.  6 B  shows an example of a heated region localized to a perimeter of the central region. 
     For silicate glasses, plots of viscosity versus temperature can be used to identify temperatures relevant to deformation of the glass. For example, the strain point (viscosity of about 10 14.5  Poise) is the temperature at which internal stress in the glass is relieved in hours. The annealing point (viscosity of about 10 13.2  to 10 13.4  Poise) is the temperature at which internal stress in the glass is relieved in minutes. The glass transition temperature (viscosity of about 10 12  to 10 13  Poise) is the temperature at which glass transitions from a super-cooled liquid to a glassy state. The dilatometric softening point is defined by a viscosity of about 10 9  to 10 11  Poise while the Littleton softening point is defined by a viscosity of about 10 7.6  Poise; a “softening point” as referred to herein may refer to either of these temperatures. The working point is defined by a viscosity of about 10 4  Poise. The melting range may be defined by a viscosity of about 10 1.5  Poise to about 10 2.5  Poise. 
     In some cases, at least a portion of the glass workpiece may be heated to a temperature range from a softening point to a working point of the glass workpiece in the operation  404 . In additional cases, at least a portion of the glass workpiece may be heated to a temperature range from a working point to a melting point of the glass workpiece in the operation  404 . In some cases, the glass workpiece may be heated to a temperature from about 800° C. to about 1000° C. The temperature may be controlled so that the glass workpiece does not sag excessively before reaching the molds of the forming process. As an example, the strain point of an aluminosilicate glass such as an alkali aluminosilicate glass may be from about 525° C. to about 575° C.; the annealing point of the aluminosilicate glass may be from about 600° C. to about 650° C., and the working point may be greater than 1000° C., such as from about 1100° C. to about 1300° C. The glass transition temperature may be from about 575° C. to about 625° C. As an additional example, the aluminosilicate glass may be configured to have a lower working temperature and glass transition temperature, such as a working temperature from about 900° C. to about 1100° C. and a glass transition temperature from about 500° C. to about 550° C. In some cases, the (maximum) temperature to which the glass workpiece is heated before forming may be referred to as a first temperature. 
     The process  400  further includes an operation  406  of forming a portion of the glass workpiece to form a molded glass workpiece. The operation  406  may also be referred to herein as a thermoforming operation, a molding operation, a reforming operation, a hot stamping operation, or a shaping operation and the molded glass workpiece may also be referred to herein as a reformed or a reshaped glass workpiece or simply as a molded, reformed, or reshaped glass workpiece. In some embodiments, at least a portion of the glass workpiece is deformed between multiple mold members to produce a molded glass workpiece. For example, the portion of the glass workpiece may be deformed between a cavity mold and a core mold, examples of which are shown in  FIG.  8   . The glass workpiece may be deformed by bending, by stretching, by flow, or in some cases by combinations of these. The portion of the glass workpiece that is formed may also be referred to as a first portion of the glass workpiece and the formed portion of the molded glass workpiece may also be referred to as a first portion of the molded glass workpiece. 
     Pressure may be applied between the mold members, such as the cavity mold and the core mold. For example, the pressure may be applied in a press or other forming apparatus. In some embodiments, additional energy may be supplied to the glass workpiece during the forming operation to facilitate glass flow and/or formability. For example, in some cases the operation  406  may be assisted by use of ultrasonic vibration. The forming process may be completed in 10 seconds or less, such as from about 2 seconds to about 7 seconds or from about 3 seconds to about 5 seconds. The operation  406  may take place in an air atmosphere or in a vacuum or inert gas atmosphere. 
     As the glass workpiece begins the forming operation  406 , at least a portion of the glass workpiece is at a temperature at which the glass can be deformed. In some cases, this portion of the glass workpiece may be at a temperature from a softening point to a working point of the glass workpiece. A temperature about equal to a softening point of the glass workpiece may be useful when the change in shape during forming of the glass workpiece is achieved largely by bending. A temperature about equal to a working point of the glass workpiece may be useful when the change in shape during forming of the glass workpiece is achieved largely by stretching but the glass workpiece retains substantially uniform thickness. Temperatures in a range from a working point to a melting point of the glass workpiece may be useful when the change in shape during forming of the glass workpiece is achieved largely at least in part by flow of the glass material of the glass workpiece. In cases where high shear rates cause shear thinning, adequate viscous flow may occur at lower temperatures than are otherwise possible. 
     Each of the mold members may be heated to a temperature less than the temperature of the glass workpiece. For example, each of the cavity mold and the core mold may be heated to a temperature within about 75° C., 50° C., or 25° C. of the glass transition temperature for the glass workpiece. In some cases, the cavity and the core molds may be heated to a temperature from 500° C. to 600° C. In some embodiments, the mold temperature may not be uniform, such as when one or more mold temperatures are configured to locally control the viscosity to encourage and/or restrict deformation of the glass workpiece. Contact between the glass workpiece and the cooler cavity mold and core mold during the forming operation can therefore begin to cool the glass workpiece to help retain the shape change from the forming operation. The cooling of the glass workpiece within the mold may be rapid compared to the cooling rates in later cooling operations. The molded glass workpiece may be cooled to a temperature within about 50° C. or 25° C. of the glass transition temperature for the glass workpiece before the molded glass workpiece (in the frame) is removed from the mold. In some cases, the (maximum) temperature to which the mold member(s) is/are heated before forming may be referred to as a second temperature. 
     In some cases, the peripheral portion of the glass workpiece may tend to move within the frame during the forming operation. In embodiments, movement of the peripheral portion of the glass workpiece within the frame is controlled by the weight of a frame component sitting on the glass and/or due to application of pressure to compress the two frame components against the glass workpiece. Pressure may be applied to compress the two frame components against the glass workpiece as previously discussed with respect to operation  402 . The peripheral portion of the glass workpiece may define a peripheral portion of the molded glass workpiece, also referred to herein as a flange of the molded glass workpiece. 
     In some cases, the cavity of the cavity mold defines surfaces having different orientations. In some examples, the cavity of the cavity mold may be defined by a substantially planar recessed surface and a wall surface extending from the planar recessed surface. An example of this shape is shown in  FIG.  8   . A first region of the glass workpiece may be molded against the planar recessed surface and a second region of the glass workpiece may be molded against the wall surface. The first region and the second region may be located within the central portion of the glass workpiece. 
     The first region of the glass workpiece may make up a first portion of the glass component, such as the central portion  292  of the glass component  232  or the plateau of the protruding portion  336  of the glass component  334 . The second region of the glass workpiece may make up a second portion of the glass component extending from the first portion, such as the peripheral portion  294  of the glass component  232  in  FIG.  2    or the side of the protruding feature  336  in  FIG.  3 B . 
     The cavity mold and the core mold are typically configured to withstand elevated temperatures. In some cases, these molds may be formed from one or more materials such as high purity chromium (e.g., a purity of at least 99.95%), noble metals (e.g., Pt, Rd, Ir, or alloys thereof such as Pt—Ir), or ceramic materials such as tungsten carbide, alumina, zirconia, and the like. The ceramic materials may have fine grains. For example, these molds may be formed from bulk chromium or ceramic materials with noble metal coating, noble metal alloy coating, or ceramic coating on the core and the cavity surfaces. Examples of suitable coatings include, but are not limited to, coatings of one or more of noble metals and noble metal alloys such as Pt—Ir, oxides such as aluminum oxide, nitrides such as titanium nitride or titanium aluminum nitride, carbonitrides such as titanium carbonitride, and the like. 
     In some cases, a surface of a mold and/or a glass workpiece may be modified to help control the movement of the glass workpiece against the mold. The modifications may include one or more of a temporary or permanent coating, a texture, a gaseous cushion/slip plane, or the like. For example, a coating may be applied to all or part of a glass workpiece surface to lower the friction between the glass workpiece surface and the mold surface. Suitable coatings include, but are not limited to, graphite or boron nitride powder coatings or vaporizable coatings that produce a gaseous cushion between the glass workpiece surface and the mold surface. As an additional example, the mold surface may be coated to lower the friction or textured to increase the friction between the mold surface and the glass workpiece. 
     The process  400  includes an operation  408  of cooling the molded glass workpiece following the operation  406  and prior to the operation  410  of removing the molded glass workpiece from the frame. The operation  408  may cool the molded glass workpiece to an ambient temperature (e.g., room temperature, about 25° C.), an ambient temperature range, or a temperature range sufficiently below a transition temperature of the glass component (e.g., a strain point or a glass transition point). The operation  408  may include multiple stages as shown schematically in  FIG.  5   . 
     The process  400  may include additional operations which produce the glass component from the molded glass workpiece. For example, the process  400  may include one or more finishing operations  412 . In some cases, the one or more finishing operations include a trimming operation. In the trimming operation, a portion of the molded glass workpiece (e.g., a second portion) may be at least partially removed or trimmed from another portion of the molded glass workpiece (e.g., a first portion). For example, at least some of the peripheral portion of the molded glass workpiece may be removed to obtain the desired shape of the glass component. As a particular example, the peripheral portion (e.g., flange) of a molded glass workpiece formed using a mold similar to that shown in  FIG.  8    can be removed to produce a glass component having a shape similar to that shown in  FIG.  2   . The first portion of the molded glass workpiece (with respect to a trimming operation) may define the central portion of the glass component (e.g., the central portion  292  of the glass component  232 ) and the peripheral portion of the glass component (e.g., the peripheral portion  294  of the glass component  232  in  FIG.  2   ). Any suitable separation technique may be used during the trimming operation, such as a laser separation process, a mechanical separation process, or a combination thereof. 
     The one or more finishing operations  412  may optionally include an operation of creating one or more through-holes through the glass component (e.g., the through-hole  362  in  FIG.  3 B ). The operation of creating the through-hole can employ any suitable process, such as a mechanical process, a laser-based process, or a combination thereof. In additional examples, the one or more finishing operations  412  may include one or more cleaning, polishing, and/or texturing operations. 
     In some embodiments, the process  400  may further include an annealing operation to relieve residual thermal stresses from the heating and forming operations. The annealing operation may take place while the molded glass workpiece is in the frame or following its removal from the frame. 
     In additional examples, the process  400  may include a chemical strengthening operation. The glass component may be chemically strengthened by one or more ion exchange operations. During the ion exchange operation, ions present in the glass component can be exchanged for larger ions in a region extending from a surface of the glass component. The ion exchange may form a compressive stress layer (or region) extending from a surface of the glass component. In some embodiments, a compressive stress layer is formed at each of the exterior surface and the interior surface of the glass component. A tensile stress layer may be formed between these compressive stress layers. 
       FIG.  5    schematically shows a series of stages in a process  500  for forming a glass component. The process  500  shown in  FIG.  5    may be an example of the process  400  described with respect to  FIG.  4   . The glass workpiece  552  and the frame  572  may be transferred from one stage to another by equipment automated to reduce the overall time of the process  500 . 
     As shown in  FIG.  5   , the glass workpiece  552  is placed into a frame  572  in the stage  502 . The stage  502  may correspond to the operation  402  of  FIG.  4   . The glass workpiece  552  and the frame  572  may be any of the glass workpieces and frames described with respect to  FIG.  4   . By the way of example, the glass workpiece may be larger than shown in  FIG.  5    to allow the glass workpiece to extend between two faces of a sandwich frame (as shown in  FIGS.  6 A and  6 B ). In some cases, the glass workpiece  552  and the frame  572  may be placed into a cell prior to the next stage in the process  500 . 
     While the glass workpiece  552  is in the frame  572 , the glass workpiece  552  is heated in the stages  504 ,  506 , and  508 . The stages  504 ,  506 , and  508  may correspond to the operation  404  of  FIG.  4   . As previously discussed with respect to  FIG.  4   , the number of heating stages may depend on the composition and/or shape of the glass component and is not limited to the number of stages shown in  FIG.  5   . Typically, at least a portion of the glass workpiece  552  is heated to a higher temperature in the stage  506  than in the stage  504  and to a higher temperature in the stage  508  than in the stage  506 . The glass workpiece may be heated as described with respect to  FIG.  4    and that description is not repeated here. 
     While the glass workpiece  552  is in the frame  572 , the glass workpiece  552  is formed during the stage  510 . The stage  510  may correspond to the operation  406  of  FIG.  4   . As previously described with respect to  FIG.  4   , the glass workpiece  552  may be formed between a cavity mold and a core mold and the forming operation may take place in a press. The mold(s) in which the glass workpiece  552  is formed may be cooler than the heated glass workpiece, allowing forming and cooling of the glass workpiece to take place simultaneously within the mold. The cooling of the glass workpiece within the mold may be rapid compared to the later cooling stages  512 . 
     Following the stage  510 , the molded glass workpiece is cooled during the stages  512  and  514 . The stages  512  and  514  may correspond to the operation  408  of  FIG.  4   . The number of cooling stages is not limited to the number of stages shown in  FIG.  5    and in additional examples more or fewer cooling stages may be used. The molded glass workpiece may be cooled as described with respect to  FIG.  4    and that description is not repeated here. 
     Following the stage  514 , the molded glass workpiece  562  is removed from the frame  572  in the stage  516 . The stage  516  may correspond to the operation  410  of  FIG.  4   . As previously described with respect to example 4, the molded glass workpiece  562  may be subjected to one or more of a finishing operation, an annealing operation, and a chemical strengthening operation. 
       FIG.  6 A  schematically illustrates a cross-sectional view of an operation of heating the glass workpiece. The glass workpiece  652  of  FIG.  6 A  is held horizontally in a frame  672  which exposes a first surface  654  and a second surface  655  of the glass workpiece. In particular, the frame  672  holds a peripheral portion  694  and exposes a central portion  692  of the glass workpiece  652 . 
     In the example of  FIG.  6 A , the glass workpiece  652  is heated from above and below with a pair of heaters  682 . The heaters  682  and the frame  672  are sized so that a surface of each of the heaters facing the glass workpiece fits within an opening defined by the frame  672  (see the opening  875  of  FIG.  8   ). The heaters  682  may be configured to produce a heated region which includes the entire central portion of the glass workpiece, as schematically illustrated in  FIG.  7 A . In the example of  FIG.  6 A , each of the heaters  682  includes internal heating elements  683 . 
       FIG.  6 B  schematically illustrates a cross-sectional view of another operation of heating the glass workpiece. The glass workpiece  652  of  FIG.  6 B  is held horizontally in a frame  672  which exposes a first surface  654  and a second surface  655  of the glass workpiece. As previously described with respect to  FIG.  6 A , the frame  672  holds a peripheral portion  694  and exposes a central portion  692  of the glass workpiece  652 . In the example of  FIG.  6 B , the glass workpiece  652  is heated from above and below with a pair of heaters  684 . The heaters  684  and the frame  672  are sized so that a surface of each of the heaters facing the glass workpiece fits within an opening defined by the frame  672 . The heaters  684  may be configured to produce a heated region which is localized around a perimeter of the central portion of the glass workpiece, as schematically illustrated in  FIG.  7 B . In the example of  FIG.  6 B , each of the heaters  684  includes internal heating elements  685 . 
       FIG.  7 A  schematically shows local heating of an entire central portion of a glass workpiece  752 . The shading indicates the heated region  762  of the glass workpiece. As shown in  FIG.  7 A , the heated region  762  extends over the entire central portion  756  of the glass component.  FIG.  7 A  may be an example of local heating during the operation  404  of the process  400 . The heated region  762  may define a heating pattern for the glass workpiece. In some examples, the most deformation and/or reshaping occurs in the vicinity of the dashed line  742 . In some cases, the dashed line may also indicate a periphery of the glass component. The peripheral portion  754  of the glass workpiece may be actively cooled or may be heated to a lesser extent than the central portion during at least a portion of a process cycle in which the glass workpiece is thermoformed. 
       FIG.  7 B  schematically illustrates local heating of less than the entire central portion of a glass workpiece  752 . The shading indicates the heated region  764  of the glass workpiece. In the example of  FIG.  7 B , the heated region  764  is localized around a perimeter of the central portion  756  of the glass workpiece and around the dashed line  742 . The heated region  764  may generally correspond to a region of localized deformation of the glass workpiece. When the glass component has a shape similar to that of the glass component  232  of  FIG.  2   , the heated region  764  may correspond to the peripheral region  294 . The heated region  764  may define a heating pattern for the glass workpiece. 
       FIG.  8    shows an exploded view of a frame  870  supporting a glass workpiece  852  and a core mold  892  and a cavity mold  896 . The core mold  892  and the cavity mold  896  may be used during a forming operation such as the operation  406  of  FIG.  4   . 
     As shown in  FIG.  8    the glass workpiece  852  is horizontally oriented and is positioned between two frame components  872   a  and  872   b  of the frame  870 . The frame component  872   b  supports the glass workpiece  852 . The frame components  872   a  and  872   b  define a central opening  875  which exposes a central portion  882  of the glass workpiece. An exposed first surface on an underside of the glass workpiece  852  contacts the cavity mold  892  during the forming operation. An exposed second surface  855  of the glass workpiece  852  contacts the core mold  896  during the forming operation. The frame  870  and the cavity and core molds ( 892 ,  896 ) are sized so that a surface of each of the cavity and core molds fits within the central opening  875 . The glass workpiece  852  and the frame  870  may be similar to the glass workpieces and the frames described with respect to  FIG.  4    and those details are not repeated here. 
     The cavity mold  892  defines a cavity  893  and the core mold  896  defines a protruding feature  897 . Typically, the protruding feature  897  is complementary in shape to at least a portion of the cavity  893 . In the example of  FIG.  8   , the cavity  893  of the cavity mold  892  defines a substantially planar recessed surface  894  and a wall surface  895  extending from the planar recessed surface. A first region of the glass workpiece  852  may be molded against the substantially planar recessed surface  894  to produce a substantially planar region of the molded glass workpiece. A second region of the glass workpiece may be molded against the wall surface  895  to produce an angled region of the molded glass workpiece. The first and the second regions may be regions of the central portion  882  of the glass workpiece. The cavity mold  892  and the core mold  896  may be similar to the molds described with respect to  FIG.  4    and those details are not repeated here. The mold shape shown in  FIG.  8    is not intended to be limiting and in additional examples the recessed surface need not be planar but may be curved instead. In further examples, the shape and orientation of the surface extending from this recessed surface may be curved and/or at a different angle than shown in  FIG.  8    as was previously described with respect to  FIG.  2   . 
     As previously discussed, the present disclosure also provides bonding techniques, which may be non-isothermal bonding techniques.  FIG.  9    shows a partial cross-section view of an example glass component  934  produced using a bonding technique. The component  934  may be an example of the cover member  133  of  FIG.  1 B  and the cross-section view may be along B-B in  FIG.  1 B . For simplicity, only one through-hole  962  is shown in  FIG.  9   . More generally, the glass component  934  may define additional through-holes as previously described with respect to  FIG.  1 B . 
     As shown in  FIG.  9   , the glass component  934  includes a first constituent  999  and a second constituent  996 . The first constituent  999  is bonded to the second constituent  996  in the example of  FIG.  9   . The first constituent  999  underlies the second constituent  996 , and the second constituent  996  typically has at least one lateral dimension (e.g., W 1 ) that is smaller than that of the first constituent  999 . 
     The glass component  934  may be a glass cover member, the first constituent  999  may be a first glass constituent, and the second constituent  996  may be a second glass constituent. In additional cases, the glass component  934  is a composite member. As one example, the first constituent  999  is a first glass constituent and the second constituent  996  is a glass ceramic or ceramic component. A first constituent, such as the first constituent  999 , may also be referred to herein as a first portion or in some cases as a first layer or piece. A second constituent, such as the second constituent  996 , may also be referred to herein as a second portion or in some cases as a second layer or piece. 
     The first constituent  999  includes or defines the portion  939  of the glass component  934 , also referred to herein as a base portion  939 . The base portion  939  defines a base region  949  of the exterior surface  944 . The first constituent  999  also includes the portion  935  underlying the protruding feature  936 . The protruding feature  936  protrudes from or is at least partially offset with respect to the base portion  939 . A protruding feature of a component, such as the protruding feature  936 , may also be referred to generally herein as a feature. 
     The second constituent  996  of the glass component may at least partially define the protruding feature  936  of the glass component  934 . In the example of  FIG.  9   , the second constituent  996  wholly defines the protruding feature  936 . However, in other examples the second constituent  996  may partially define the protruding feature. For example, a finishing operation which removes part of the base region  949  of the exterior surface of the bonded workpiece may cause the first constituent to define a portion of the protruding feature. 
     The protruding feature  936  defines a raised region  947  of the exterior surface  944 . The raised region  947  also defines a top surface of the protruding feature. The raised region  947  may define a plateau (a substantially planar surface region). In the example of  FIG.  9   , the raised region  947  of the exterior surface is offset by a distance H 1  from the base region  949  of the exterior surface. The protruding feature  936  also defines a side region  948  that extends between the raised region  947  and the base region  949  of the exterior surface  944  and a width W 1 . 
     The dashed line  995  schematically indicates the boundary region between the first constituent  999  and the second constituent  996 . The boundary region may join the first constituent to the second constituent. In some cases, the first constituent  999  may be fused to the second constituent  996 , such as when the first constituent  999  is a first glass constituent and the second constituent  996  is a second glass constituent. When the first constituent  999  is fused to the second constituent  996  the boundary region may also be referred to herein as a fusion zone. In some embodiments, the fusion between the first constituent  999  and the second constituent  996  is substantially complete. For example, the boundary or fusion zone between the first constituent  999  and the second constituent  996  may include few, if any, voids, and any voids present may be small relative to the thickness of the first and the second constituent. 
     The first constituent  999  of the glass component  934  may be formed from a first layer or piece of glass and the second constituent  996  of the glass component may be formed from a second layer or piece of glass. The dashed line  995  may correspond to the boundary between the first layer or piece of glass and the second layer or piece of glass. In some cases, a distinct boundary region may be observed between the first constituent  999  and the second constituent  996 . In other cases, a distinct boundary region between the first constituent  999  and the second constituent  996  may not be detected by the unaided eye. 
     For example, a distinct fusion zone may not be detected by the unaided eye when the first layer of glass has a composition that is substantially similar to that of the second layer of glass and fusion between the first glass constituent and the second glass constituent is substantially complete. In some cases, one or more fusion artifacts may be detected in the fusion zone such as an area of incomplete fusion, a void, a graphite, or other impurity particle arising from the bonding process, and the like. The size of any fusion artifacts may be sufficiently small that the glass component has the desired strength. In some cases, the boundary region and/or a fusion artifact may be observed by sectioning the glass component  934  and/or using non-destructive techniques. Suitable techniques for observing the boundary region and/or a fusion artifact include, but are not limited to, microscopy, elemental analysis, optical interference detection, ultrasonic detection, and the like. 
     As shown in  FIG.  9   , the glass component  934  further defines a through-hole, such as the through-hole  962 . The through-hole  962  extends through the protruding feature  936  and the underlying portion  935  of the glass component  934 . The first constituent  999  of the glass component  934  may define a lower or first portion of the through-hole  962  and the second constituent  996  of the glass component may define an upper or second portion of the through-hole  962 . 
     The through-hole  962  may allow input to, output from, and/or placement of a device component such as an optical module as previously described with respect to  FIG.  1 B . The protruding feature  936  may further define an opening  967  to the through-hole, with the opening  967  being located in the raised region  947 . In some cases, the glass component  934  may define an arrangement, array, or set of through-holes and openings extending through the protruding portion  936 . For example, the glass component  934  may define any number of through-holes and openings, such as one, two, three, four, or five through-holes and openings. 
     In the example of  FIG.  9   , the raised region  947  of the exterior surface is offset by a distance H 1  from the base region  949  of the exterior surface. The thickness T 2  (the distance between the interior surface  942  and the raised region  947 ) is greater than the thickness T 1  (the distance between the interior surface  942  and the base region  949  of the exterior surface). As examples, the ratio T 2 /T 1  may be from about 1.25 to about 3 or from about 1.5 to about 2. In some cases, the protruding feature  936  has a thickness greater than about 1 mm and less than or equal to about 2.5 mm and the base portion  939  has a thickness greater than about 0.5 mm and less than about 1 mm. The amount of protrusion or offset between the raised region  947  and the base region  949  may be from about 0.5 mm to about 1.5 mm or from about 0.75 mm to about 2 mm. 
     In some cases, the base region  949  and the raised region  947  may both define respective textured regions of the exterior surface  944  (also referred to herein as textured surface regions). For example, the raised region  947  may define a first texture and the base region  949  may define a second texture different than the first texture. The different textures may be created by one or more finishing processes. 
       FIG.  10    shows a partial cross-section view of another example glass component  1034  produced using a bonding technique. The component  1034  may be an example of the cover member  133  of  FIG.  1 B  and the cross-section view may be along B-B in  FIG.  1 B . For simplicity, only one through-hole  1062  is shown in  FIG.  10   . More generally, the glass component  1034  may define additional through-holes as previously described with respect to  FIG.  1 B . The greater width of a first portion  1063   a  of the through-hole  1062  may be sized to accommodate one or more internal components of the electronic device. 
     As shown in  FIG.  10   , the glass component  1034  includes a first constituent  1099  and a second constituent  1096 . The first constituent  1099  is bonded to the second constituent  1096  along a boundary region schematically indicated by the dashed line  1095 . The first constituent  1099  underlies the second constituent  1096 , and the second constituent  1096  typically has at least one lateral dimension (e.g., W 2 ) that is smaller than that of the first constituent  1099 . As previously described with respect to  FIG.  9   , the first constituent  1099  may be formed from a first layer or piece of glass and the second constituent  1096  may be formed from a second layer or piece of glass. The dashed line  1095  may correspond to the boundary between the first layer or piece of glass and the second layer or piece of glass. In the example of  FIG.  10   , the boundary region  1095  extends around a perimeter of the second constituent  1096 . The width of the boundary region  1095  is limited by the overlap between the first and the second constituents, which in turn is limited by the through-hole  1062  (and hole portions  1063   a  and  1063   b ). Therefore, the boundary region  1095  may be referred to herein as a perimeter boundary region or perimeter fusion zone. 
     The first constituent  1099  includes or defines the portion  1039  of the glass component  1034 , also referred to herein as a base portion  1039 . The base portion  1039  defines a base region  1049  of the exterior surface  1044 . The first constituent  1099  also includes the portion  1035  underlying the protruding feature  1036 . The protruding feature  1036  protrudes from or is at least partially offset with respect to the base portion  1039 . A protruding feature of a component, such as the protruding feature  1036 , may also be referred to generally herein as a feature. 
     The second constituent  1096  of the glass component may at least partially define the protruding feature  1036  of the glass component  1034 . In the example of  FIG.  10   , the second constituent  1096  wholly defines the protruding feature  1036 . However, in other examples the second constituent  1096  may partially define the protruding feature. For example, a finishing operation which removes part of the base region  1049  of the exterior surface of the bonded workpiece may cause the first constituent to define a portion of the protruding feature. 
     As shown in  FIG.  10   , the glass component  1034  further defines a through-hole  1062 . The through-hole  1062  extends through the protruding feature  1036  and the underlying portion  1035  of the glass component  1034 . The first constituent  1099  of the glass component  1034  may define a lower or first portion  1063   a  of the through-hole  1062  and the second constituent  1096  of the glass component may define an upper or second portion  1063   b  of the through-hole  1062 . As shown in  FIG.  10   , a lateral dimension W 3  of the first portion  1063   a  is greater than a lateral dimension W 4  of the second portion  1063   b  of the through-hole  1062 . In some cases, the shape of the through-hole  1062  may be achieved by forming a through-hole through the layer of glass which is to become the first constituent of the glass component  1034 , as shown in the example of  FIG.  13 A . 
     The through-hole  1062  may allow input to, output from, or placement of one or more device components. For example, the second portion  1063   b  of the through-hole  1062  may allow placement of an optical module as previously described with respect to  FIGS.  1 B and  9   . The first portion  1063   a  may accommodate the optical module and also accommodate one or more additional components of the electronic device. 
     The protruding feature  1036  defines a raised region  1047  of the exterior surface  1044 . The raised region  1047  also defines a top surface of the protruding feature. The raised region  1047  may define a plateau (a substantially planar surface region). In the example of  FIG.  10   , the raised region  1047  of the exterior surface is offset by a distance H 2  from the base region  1049  of the exterior surface. The protruding feature  1036  also defines a side region  1048  that extends between the raised region  1047  and the base region  1049  of the exterior surface  1044  and a width W 2 . The raised region  1047  of the exterior surface is offset by a distance T 4  from the interior surface  1042  and the base region  1049  of the exterior surface is offset by a distance T 3  from the interior surface  1042 . The raised region  1047  also defines an opening  1067  to the through-hole  1062 . The values for the distances H 2 , T 3 , and T 4  may be similar to the values described with respect to  FIG.  9    for H 1 , T 1 , and T 2 . 
       FIG.  11    shows a flow chart of an example process  1100  for making a glass component by bonding together glass layers of a workpiece. The description provided below with respect to bonding of glass layers also applies more generally to bonding of glass pieces. The process  1100  may be performed at several stations, as was previously described for the process  400 . The time spent at each station may be limited to more rapidly produce the glass component. For example, the time spent at each station may be 20 seconds or less, from about 2 seconds to about 20 seconds, or from about 5 seconds to about 20 seconds. 
     As shown in  FIG.  11   , the process  1100  includes an operation  1102  of placing a workpiece comprising an assembly of glass layers into a frame. The layers of the assembly may be precisely aligned with each other. In some cases, the layers may be assembled simply by placing them in contact with one another. In additional cases, the glass layers of the assembly may be at least partially bonded to maintain the position of the layers during the fusing operation. For example, laser bonding, static adhesion, optical bonding, or the like may be used to at least partially bond the layers. A separate fixture or station may be used to assemble the layers.  FIGS.  12 B and  13 B  show examples of an upper glass layer tack welded to a lower glass layer. The assembly may be performed under clean conditions to limit introduction of foreign matter between the glass layers.  FIGS.  12 A through  12 C and  13 A through  13 C  schematically show assembly of a workpiece and placement of the workpiece into the frame. The frame may be any of the frames previously described with respect to  FIG.  4    and, for brevity, that description is not repeated here. 
     The glass layers used to form the workpiece may be shaped prior to assembling the glass layers. For example, the glass layers may be shaped to a desired shape and size by machining. In some embodiments, a through-hole may be formed in one or more of the glass layers prior to assembly of the layers as shown in  FIG.  13 A . In additional examples, the surfaces of the glass layers may be finished so that adjacent layers can closely contact each other. In some cases, the surfaces of adjacent glass layers are substantially flat and smooth. In some examples one or more of the glass layers may be cleaned and/or may be treated with one or more surface treatments such as etching and plasma treatment prior to assembly. The glass layers may be in direct contact with one another or in some embodiments an intermediate layer may be provided to enhance bonding between the glass layers. The glass layers need not have the same lateral dimensions, as shown in the examples of  FIGS.  12 A through  12 C and  13 A through  13 C . 
     In some cases, each of the glass layers has a substantially similar composition. In additional cases, the glass layers may differ in composition. In some examples, the thickness of the first glass layer forming the first or lower portion of the glass component is from 0.5 mm to 1.0 mm, or from 0.75 mm to 1.5 mm, and the thickness of the glass layer(s) forming the upper portion(s) of the glass component is from 0.75 to 1.5 mm or from 1.0 mm to 2 mm. The composition of each of the glass layers may be as previously described with respect to  FIG.  2    and that description is not repeated here. 
     The process  1100  also includes an operation  1104  of heating the workpiece. As examples, at least a portion of the workpiece may be heated to a temperature between the glass transition temperature and a softening point of each of the glass layers, to a temperature between an annealing point and a softening point of each of the glass layers, or to a temperature between a strain point and a softening point of each of the glass layers. The operation  1104  may take place in an air atmosphere or in a vacuum or inert gas atmosphere. 
     In some embodiments, the operation  1104  may locally heat the workpiece as schematically shown in  FIGS.  14 A,  14 B, and  14 C . In some cases, an upper layer of the workpiece may be heated over its entire upper surface while the lower layer is heated to a lesser extent, as shown schematically in  FIG.  14 A . In additional cases, the heating may be localized around a periphery of the upper layer as shown schematically in  FIGS.  14 B and  14 C . The localized heating may form one or more temperature gradients, as schematically shown in  FIG.  14 C . For example, the temperature gradient may be configured to “feather” a heat affected zone in the workpiece. Alternately, the workpiece may be globally, rather than locally, heated. 
     The process  1100  further includes an operation  1106  of bonding the glass layers to form a bonded assembly (which may also be referred to herein as a bonded workpiece). The operation  1106  may comprise fusing the glass layers to bond them together and the bonded assembly may be a fused assembly. In embodiments, the fusing operation comprises applying pressure to at least the upper layer of the assembly. The pressure may be applied between two tool-pieces and a press or similar apparatus may be used to apply the pressure. In some cases, each of a first tool-piece and a second tool-piece defines a planar region. In some cases, one tool piece supports the assembly of the glass layers while another tool-piece, such as plunger, piston, or the like contacts the upper layer of the assembly, as schematically illustrated in  FIG.  15   . In some embodiments, the tool-pieces may be press heads. The operation  1106  may take place in an air atmosphere or in a vacuum or inert gas atmosphere. 
     As previously discussed, the assembly of the glass layers may be preheated to a temperature between the glass transition temperature and a softening point of each of the glass layers, to a temperature between an annealing point and a softening point of each of the glass layers, or to a temperature between a strain point and a softening point of each of the glass layers. In some cases, additional energy may be supplied to the glass workpiece during the bonding operation to facilitate fusion of the glass layers. For example, the operation  1106  may be ultrasonic-assisted and/or additional heating may be provided by the tool-pieces. As a specific example, the tool-pieces may include susceptors. In additional examples the tool-pieces may be at a lower temperature than the assembly of the glass layers. For example, the tool-pieces may be at temperatures previously described with respect to the molds of process  400 . 
     The operation  1106  creates an integrally bonded assembly, which may be a fused assembly. In some cases, one or more portions of the bonded assembly are produced from a greater number of layers than other portions of the bonded assembly. The one or more portions of the bonded assembly produced by bonding a greater number of layers may be thicker than the other portions of the bonded assembly. For example, a portion of the bonded assembly produced by bonding multiple layers of glass can have a greater thickness than a portion of the bonded assembly which is produced from a single layer of glass, as shown in the examples of  FIGS.  12 A through  12 C and  13 A through  13 C . In some cases, at least a portion of a boundary region between the glass layers may be detected by the unaided eye or using other techniques after the operation of fusing the glass layers as previously discussed with respect to  FIG.  9   . 
     The one or more portions of the bonded assembly produced by bonding a greater number of layers of glass may protrude with respect to other portions of the bonded assembly. For example, a portion of the bonded assembly produced by bonding multiple layers of glass may protrude with respect to an adjacent portion produced from a single layer of glass. In particular, the thicker portion of the bonded assembly may protrude from an adjacent thinner portion of the bonded assembly. As shown in the examples of  FIGS.  9  and  10   , a protruding feature of the glass component may be located within the thicker portion, while the base portion of the glass component may be located within an adjacent thinner portion. 
     In some embodiments, the operation  1106  of bonding the glass layers may be combined with an operation of forming one or more glass layers. For example, a heating pattern as shown in  FIG.  16    may be used to locally heat the glass workpiece for a combined forming and bonding operation. 
     The process  1100  includes an operation  1108  of cooling the bonded assembly, which follows the operation  1106 . The operation  1108  may cool the bonded assembly to an ambient temperature (e.g., room temperature), an ambient temperature range, or a temperature range sufficiently below a transition temperature of the glass component (e.g., a strain point or a glass transition point). The operation  1108  may include multiple stages. Following the operation  1108 , the process  1100  includes an operation  1110  of removing the bonded assembly from the frame. As previously discussed, the bonded assembly may be a fused assembly. 
     In some embodiments, the bonded assembly may be ready for use as the glass component after the operation  1108 . In additional embodiments, the process  1100  includes additional operations which produce the glass component from the bonded assembly. For example, the process  1100  may include one or more finishing operations. In some cases, a peripheral portion of the bonded assembly is trimmed to achieve the desired shape of the glass component and or one or more through-holes may be formed and/or enlarged (e.g., by machining). In further examples, the bonded assembly may be cleaned, textured, and/or polished. As an additional example, the process may include an annealing operation to relieve residual thermal stresses from the heating and bonding operations. The annealing operation may take place while the bonded assembly is in the frame or following its removal from the frame. In additional examples, the glass component may be chemically strengthened by one or more ion exchange operations. These operations may be similar to those described with respect to the process  400  of  FIG.  4    and, for brevity, that description is not repeated here. 
       FIGS.  12 A,  12 B, and  12 C  schematically show an example of assembly of a workpiece and placement of the workpiece into a frame.  FIG.  12 A  shows a first glass layer  1249  and a second glass layer  1246 . The second glass layer has lateral dimensions (e.g., a width) smaller than that of the first glass layer  1249 . The first glass layer  1249  and the second glass layer  1246  may have a thickness, a composition, and/or other properties as previously described for the glass layers of  FIG.  11    and that description is not repeated here. The dashed line  1242  may schematically illustrate the periphery of the glass component. The position of the dashed line  1242  shown in  FIG.  12 A  is not limiting and in some embodiments, the periphery of the glass component may correspond more closely to the periphery of the glass workpiece  1252 . 
     As shown in  FIG.  12 B , the first glass layer  1249  and a second glass layer  1246  have been assembled to form a workpiece  1252 . The features  1292  schematically illustrate localized adhesion of the first glass layer  1249  and a second glass layer  1246 . For example, the features  1292  may be formed by laser tack welding. The positioning of the second glass layer  1246  with respect to the first glass layer  1249  depicted in  FIG.  12 B  is exemplary rather than limiting and in additional examples the second glass layer  1246  may be placed in a central portion of the first glass layer  1249  or any other suitable location, such as over a particular electronic component of the electronic device. Any of the other methods described with respect to  FIG.  11    may be used to at least partially bond the first glass layer  1249  and a second glass layer  1246 . 
       FIG.  12 C  shows the workpiece  1252  after placement in a frame  1270 . In the example of  FIG.  12 C , the layer  1249  is placed in and secured to the frame  1270  while the layer  1246  is positioned in an opening  1275  defined by the frame. The frame may be any of the frames previously described with respect to  FIG.  4    and that description is not repeated here. In additional embodiments, the first glass layer may be placed in the frame prior to its assembly with the second glass layer. 
       FIGS.  13 A,  13 B, and  13 C  schematically show an additional example of assembly of a workpiece and placement of the workpiece into a frame.  FIG.  13 A  shows a first glass layer  1349  and a second glass layer  1346 . The second glass layer has lateral dimensions (e.g., a width) smaller than that of the first glass layer  1349 . In addition, the first glass layer  1349  includes a through-hole  1361  that has lateral dimensions smaller than those of the second glass layer. Therefore, the second glass layer  1346  overlaps the first glass layer  1349  around a periphery of the through-hole  1361  and the overlap allows bonding of the first glass layer  1349  to the second glass layer  1346  (as shown in  FIG.  13 B ). The lateral dimensions of the through-hole  1361  and the second glass layer  1346  are exemplary and not limited to those shown in  FIG.  13 A . The first glass layer  1349  and the second glass layer  1346  may have a thickness, a composition, and/or other properties as previously described for the glass layers of  FIG.  11    and that description is not repeated here. The dashed line  1342  may schematically illustrate the periphery of the glass component. The position of the dashed line  1342  shown in  FIG.  13 A  is not limiting and in some embodiments, the periphery of the glass component may correspond more closely to the periphery of the glass workpiece  1352 . 
     As shown in  FIG.  13 B , the first glass layer  1349  and a second glass layer  1346  have been assembled to form a workpiece  1352 . As previously described with respect to  FIG.  13 A , the first glass layer  1349  includes a through-hole  1361  that has lateral dimensions smaller than those of the second glass layer  1346 . Therefore, the second glass layer  1346  can overlap the first glass layer  1349  so that the second glass layer  1346  covers the through-hole  1361  shown in  FIG.  13 A . The features  1392  schematically illustrate localized adhesion of the first glass layer  1349  and a second glass layer  1346 . For example, the features  1392  may be formed by laser tack welding. The positioning of the second glass layer  1346  with respect to the first glass layer  1349  depicted in  FIG.  13 B  is exemplary rather than limiting and in additional examples the second glass layer  1346  may be placed in a central portion of the first glass layer  1349  or any other suitable location, such as over a particular electronic component of the electronic device. Any of the other methods described with respect to  FIG.  11    may be used to at least partially bond the first glass layer  1349  and a second glass layer  1346 . 
       FIG.  13 C  shows the workpiece  1352  after placement in a frame  1370 . In the example of  FIG.  13 C , the layer  1349  is placed in and secured to the frame  1370  while the layer  1346  is positioned in an opening  1375  defined by the frame. The frame may be any of the frames previously described with respect to  FIG.  4    and that description is not repeated here. In additional embodiments, the first glass layer may be placed in the frame prior to its assembly with the second glass layer. 
       FIGS.  14 A,  14 B, and  14 C  schematically show examples of local heating of a workpiece for a bonding operation. The examples of  FIGS.  14 A,  14 B, and  14 C  may be used in the operation  1104  of the process  1100 . The workpiece  1452  includes an upper layer  1446  and a lower layer  1449 . The workpiece is placed in a frame  1470 . The frame  1470  may be any of the frames previously described with respect to  FIG.  4    and that description is not repeated here. As previously described with respect to  FIGS.  12 B and  13 B , the relative positioning of the layers  1446  and  1449  depicted in  FIGS.  14 A to  14 C  is exemplary rather than limiting. 
     In the example of  FIG.  14 A , the upper layer  1446  of the workpiece  1452  is heated over its entire upper surface while the lower layer  1449  is heated to a lesser extent. The heated region  1462  extends over the upper layer  1446  and over a portion of the lower layer  1449 . Another portion of the lower layer  1449  that surrounds the upper layer  1446  and surrounds the underlying portion of the lower layer  1449  is not included in the heated region. In some cases, the upper layer  1446  and the underlying portion of the lower layer  1449  are heated to a higher temperature than this surrounding portion. The heated region  1462  may be uniformly heated or may include one or more temperature gradients to manage a heat affected zone of the workpiece  1452 . For example, a temperature at a periphery of the heated region  1462  may be less than a temperature at a periphery of the upper layer  1446 . The heated region  1462  may define a heating pattern for the workpiece. 
     In additional cases, the heating may be localized around a periphery of the upper layer  1446  as shown schematically in  FIGS.  14 B and  14 C . In the example of  FIG.  14 B , the heated region  1464  is localized around a periphery of the upper layer  1446  and is substantially uniform. In the example of  FIG.  14 C , the heated region  1466  is localized around a periphery of the upper layer  1446  and forms one or more temperature gradients. For example, a temperature at a periphery of the heated region  1466  may be less than a temperature inward of this periphery. As another example, the temperature may vary around the periphery of the heated region  1466 . The heated regions  1464  and  1466  may define alternate heating patterns for the workpiece. The heated regions  1464  and  1446  extend over a portion of the lower layer  1449  in the examples of  FIGS.  14 B and  14 C . Another portion of the lower layer  1449  that surrounds the upper layer  1446  and surrounds the underlying portion of the lower layer  1449  is not included in the heated regions  1464  and  1446 . In some cases, the upper layer  1446  and the underlying portion of the lower layer  1449  are heated to a higher temperature than this surrounding portion. 
     The dashed line  1442  in  FIGS.  14 A,  14 B, and  14 C  may schematically illustrate the periphery of the glass component. The position of the dashed line  1442  shown in  FIGS.  14 A,  14 B, and  14 C  is not limiting and, in some embodiments, the periphery of the glass component may correspond more closely to the periphery of the glass workpiece  1452 .  FIG.  15    schematically illustrates application of a pressure P to a workpiece  1552  in order to fuse the assembled glass layers  1546  and  1549 . In the example of  FIG.  15   , the assembly  1552  includes an upper layer  1546  and a lower layer  1549 . The upper layer  1546  contacts an upper surface  1519  of the lower layer  1549  and the boundary between these layers defines an interface  1515 . The vertical dashed lines in  FIG.  15    schematically indicate a lateral dimension of the upper layer  1546 . The glass layers  1546  and  1549  may be positioned in a frame, examples of which were previously shown in  FIGS.  12 C,  13 C, and  14 A- 14 C . 
     As shown in  FIG.  15   , a side surface  1518  of the upper layer  1546  defines a rounded shape. The example of  FIG.  15    is not limiting and the side surface  1518  may define any of a number of shapes, including a substantially planar shape or a substantially planar shape with chamfered or rounded corners. 
     A tool-piece  1525  is used to apply pressure to the upper surface  1517  of the upper layer  1546  during the fusing operation. In additional embodiments, pressure is applied by both the tool-piece  1525  and the tool-piece  1510 . As shown in  FIG.  15   , the tool-piece  1525  may have the form of a plunger with a flat bottom. The shapes of the tool-pieces shown in  FIG.  15    are not limiting and, in additional examples, the tool-piece  1525  may define a planar region and in some cases may include one or more non-planar regions. In additional examples, the tool-piece  1510  may define a planar region or in some cases may include one or more non-planar regions. For example, one of the tool-pieces may define a planar region and the other tool-piece may define a cavity. Typically, the upper layer  1546 , the lower layer  1549 , the tool-piece  1525 , and the tool-piece  1510  are at an elevated temperature during the fusing operation. The tool-pieces may be made of similar materials as previously described with respect to the cavity mold and the core mold of  FIG.  8   . The pressure and the temperature during the fusing operation may be as previously described with respect to the operation  1106  of the process  1100  and, for brevity, those details are not repeated here. 
       FIG.  16    shows an example of local heating of a workpiece  1656  for a process which combines bonding and forming techniques. The workpiece  1656  may include a lower glass layer  1649  and an upper glass layer  1646 . In the example of  FIG.  16   , the heated region  1662  is localized around the dashed line  1642  and may generally correspond to a region of localized deformation of the workpiece during the forming technique. The heated region  1664  is localized around a periphery of the layer  1646  and applies heat for the bonding technique. The workpiece  1656  includes a peripheral portion  1649  which may be supported by a frame as previously described with respect to  FIGS.  4  and  11   . As previously described with respect to  FIGS.  12 B and  13 B , the relative positioning of the layers  1646  and  1649  depicted in  FIG.  16    is exemplary rather than limiting. 
       FIG.  17    shows a block diagram of a sample electronic device that can incorporate a glass component as described herein, such as a three-dimensional glass cover member. The schematic representation depicted in  FIG.  17    may correspond to components of the devices depicted in  FIGS.  1 A to  16    as described above. However,  FIG.  17    may also more generally represent other types of electronic devices with cover assemblies as described herein. 
     In embodiments, an electronic device  1700  may include sensors  1720  to provide information regarding configuration and/or orientation of the electronic device in order to control the output of the display. For example, a portion of the display  1708  may be turned off, disabled, or put in a low energy state when all or part of the viewable area of the display  1708  is blocked or substantially obscured. As another example, the display  1708  may be adapted to rotate the display of graphical output based on changes in orientation of the device  1700  (e.g., 90 degrees or 180 degrees) in response to the device  1700  being rotated. 
     The electronic device  1700  also includes a processor  1706  operably connected with a computer-readable memory  1702 . The processor  1706  may be operatively connected to the memory  1702  component via an electronic bus or bridge. The processor  1706  may be implemented as one or more computer processors or microcontrollers configured to perform operations in response to computer-readable instructions. The processor  1706  may include a central processing unit (CPU) of the device  1700 . Additionally, and/or alternatively, the processor  1706  may include other electronic circuitry within the device  1700  including application specific integrated chips (ASIC) and other microcontroller devices. The processor  1706  may be configured to perform functionality described in the examples above. 
     The memory  1702  may include a variety of types of non-transitory computer-readable storage media, including, for example, read access memory (RAM), read-only memory (ROM), erasable programmable memory (e.g., EPROM and EEPROM), or flash memory. The memory  1702  is configured to store computer-readable instructions, sensor values, and other persistent software elements. 
     The electronic device  1700  may include control circuitry  1710 . The control circuitry  1710  may be implemented in a single control unit and not necessarily as distinct electrical circuit elements. As used herein, “control unit” will be used synonymously with “control circuitry.” The control circuitry  1710  may receive signals from the processor  1706  or from other elements of the electronic device  1700 . 
     As shown in  FIG.  17   , the electronic device  1700  includes a battery  1714  that is configured to provide electrical power to the components of the electronic device  1700 . The battery  1714  may include one or more power storage cells that are linked together to provide an internal supply of electrical power. The battery  1714  may be operatively coupled to power management circuitry that is configured to provide appropriate voltage and power levels for individual components or groups of components within the electronic device  1700 . The battery  1714 , via power management circuitry, may be configured to receive power from an external source, such as an alternating current power outlet. The battery  1714  may store received power so that the electronic device  1700  may operate without connection to an external power source for an extended period of time, which may range from several hours to several days. 
     In some embodiments, the electronic device  1700  includes one or more input devices  1718 . The input device  1718  is a device that is configured to receive input from a user or the environment. The input device  1718  may include, for example, a push button, a touch-activated button, a capacitive touch sensor, a touch screen (e.g., a touch-sensitive display or a force-sensitive display), a capacitive touch button, a dial, a crown, or the like. In some embodiments, the input device  1718  may provide a dedicated or primary function, including, for example, a power button, volume buttons, home buttons, scroll wheels, and camera buttons. 
     The device  1700  may also include one or more sensors or sensor modules  1720 , such as a force sensor, a capacitive sensor, an accelerometer, a barometer, a gyroscope, a proximity sensor, a light sensor, or the like. In some cases, the device  1700  includes a sensor array (also referred to as a sensing array) which includes multiple sensors  1720 . For example, a sensor array associated with a protruding feature of a cover member may include an ambient light sensor, a Lidar sensor, and a microphone. As previously discussed with respect to  FIG.  1 B , one or more camera modules may also be associated with the protruding feature. The sensors  1720  may be operably coupled to processing circuitry. In some embodiments, the sensors  1720  may detect deformation and/or changes in configuration of the electronic device and be operably coupled to processing circuitry that controls the display based on the sensor signals. In some implementations, output from the sensors  1720  is used to reconfigure the display output to correspond to an orientation or folded/unfolded configuration or state of the device. Example sensors  1720  for this purpose include accelerometers, gyroscopes, magnetometers, and other similar types of position/orientation sensing devices. In additional examples, the sensors  1720  may include a microphone, an acoustic sensor, a light sensor (including ambient light, infrared (IR) light, and/or ultraviolet (UV) light), an optical facial recognition sensor, a depth measuring sensor (e.g., a time of flight sensor), a health monitoring sensor (e.g., an electrocardiogram (ERG) sensor, a heart rate sensor, a photoplethysmogram (PPG) sensor, and/or a pulse oximeter), a biometric sensor (e.g., a fingerprint sensor), or other types of sensing device. 
     In some embodiments, the electronic device  1700  includes one or more output devices  1704  configured to provide output to a user. The output device  1704  may include a display  1708  that renders visual information generated by the processor  1706 . The output device  1704  may also include one or more speakers to provide audio output. The output device  1704  may also include one or more haptic devices that are configured to produce a haptic or tactile output along an exterior surface of the device  1700 . 
     The display  1708  may include a liquid-crystal display (LCD), a light-emitting diode (LED) display, an LED-backlit LCD display, an organic light-emitting diode (OLED) display, an active layer organic light-emitting diode (AMOLED) display, an organic electroluminescent (EL) display, an electrophoretic ink display, or the like. If the display  1708  is a liquid-crystal display or an electrophoretic ink display, the display  1708  may also include a backlight component that can be controlled to provide variable levels of display brightness. If the display  1708  is an organic light-emitting diode or an organic electroluminescent-type display, the brightness of the display  1708  may be controlled by modifying the electrical signals that are provided to display elements. In additional examples, information regarding configuration and/or orientation of the electronic device may be used to control the output of the display as described with respect to input devices  1718 . In some cases, the display is integrated with a touch and/or force sensor in order to detect touches and/or forces applied along an exterior surface of the device  1700 . 
     The electronic device  1700  may also include a communication port  1712  that is configured to transmit and/or receive signals or electrical communication from an external or separate device. The communication port  1712  may be configured to couple to an external device via a cable, adaptor, or other type of electrical connector. In some embodiments, the communication port  1712  may be used to couple the electronic device  1700  to a host computer. 
     The electronic device  1700  may also include at least one accessory  1716 , such as a camera, a flash for the camera, or other such device. The camera may be part of a camera assembly that may be connected to other parts of the electronic device  1700  such as the control circuitry  1710 . 
     As used herein, the terms “about,” “approximately,” “substantially,” “generally,” “similar,” and the like are used to account for relatively small variations, such as a variation of +/−10%, +/−5%, +/−2%, or +/−1%. In addition, use of the term “about” in reference to the endpoint of a range may signify a variation of +/−10%, +/−5%, +/−2%, or +/−1% of the endpoint value. In addition, disclosure of a range in which at least one endpoint is described as being “about” a specified value includes disclosure of the range in which the endpoint is equal to the specified value. 
     As used herein, the phrase “one or more of” preceding a series of items, with the term “and” or “or” to separate any of the items, modifies the list as a whole, rather than each member of the list. The phrase “one or more of” does not require selection of at least one of each item listed; rather, the phrase allows a meaning that includes at a minimum one of any of the items, and/or at a minimum one of any combination of the items, and/or at a minimum one of each of the items. By way of example, the phrases “one or more of A, B, and C” or “one or more of A, B, or C” each refer to only A, only B, or only C; any combination of A, B, and C; and/or one or more of each of A, B, and C. In addition, as used herein the phrase “one or more of” preceding a series of items, with the term “and” or “or” separating the items, does not require selection of one of each item listed; rather, the phrase allows a meaning that includes at a minimum one of any of the items, and/or at a minimum one of any combination of the items, and/or at a minimum one of each of the items. Similarly, it may be appreciated that an order of elements presented for a conjunctive or disjunctive list provided herein should not be construed as limiting the disclosure to only that order provided. 
     The following discussion applies to the electronic devices described herein to the extent that these devices may be used to obtain personally identifiable information data. It is well understood that the use of personally identifiable information should follow privacy policies and practices that are generally recognized as meeting or exceeding industry or governmental requirements for maintaining the privacy of users. In particular, personally identifiable information data should be managed and handled so as to minimize risks of unintentional or unauthorized access or use, and the nature of authorized use should be clearly indicated to users. 
     The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of the specific embodiments described herein are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings.

Metadata:
Filing Date: 20211216
Publication Date: 20250114
Grant Date: 20250114
Priority Date: 20201217
Inventors: MESCHKE, ANDREW J.
JOHANNESSEN, THOMAS
COUNTS, WILLIAM A.
Assignee: APPLE INC
CPC Classifications: [{"code": "C03B2215/406", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03B2201/32", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03B23/0307", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03B23/006", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03B23/03", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03B23/0307", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03B23/0302", "inventive": true, "first": true, "tree": "[]"}, {"code": "C03B23/0305", "inventive": true, "first": true, "tree": "[]"}, {"code": "C03B2215/406", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03B2201/32", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03B23/0307", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03B23/006", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03B23/0302", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 80112275