PATENT DOCUMENT

Publication Number: US-11269374-B2
Application Number: US-202016882361-A
Country: US
Kind Code: B2

Title: Electronic device with a cover assembly having an adhesion layer

Abstract:
A cover assembly for an electronic device has a cover member including a glass ceramic material. An adhesion layer couples an interior coating to the cover member. The adhesion layer includes an oxide-based layer, such as a silicon oxide-based layer, and a coupling agent.

Claims:
What is claimed is: 
     
       1. An electronic device comprising:
 a display; and 
 an enclosure including a cover assembly, the cover assembly positioned over the display and comprising:
 a cover member formed from a glass ceramic material; 
 a cosmetic masking layer positioned along an interior surface of the cover member and defining an opening positioned over at least a portion of the display; and 
 an adhesion layer including a silicon-based oxide and forming a bond between the glass ceramic material of the cover member and the cosmetic masking layer. 
 
 
     
     
       2. The electronic device of  claim 1 , wherein:
 the cosmetic masking layer includes a pigment dispersed within a polymer matrix; and 
 the polymer matrix is chemically bonded to the adhesion layer. 
 
     
     
       3. The electronic device of  claim 1 , wherein:
 the enclosure further includes a housing member that is coupled to the cover member by a coupling structure; and 
 the coupling structure includes the adhesion layer, the cosmetic masking layer, and an adhesive positioned between the cosmetic masking layer and the housing member. 
 
     
     
       4. The electronic device of  claim 1 , wherein the adhesion layer comprises:
 an oxide layer comprising the silicon-based oxide; and 
 a coupling agent which couples the oxide layer to the cosmetic masking layer. 
 
     
     
       5. The electronic device of  claim 1 , wherein the silicon-based oxide is characterized by the formula SiO x  and x is less than 2. 
     
     
       6. The electronic device of  claim 1 , wherein:
 the glass ceramic material comprises a lithium aluminosilicate glass ceramic; and 
 the silicon-based oxide further comprises aluminum. 
 
     
     
       7. The electronic device of  claim 1 , wherein the glass ceramic material includes at least  50  percent by volume of a crystalline phase. 
     
     
       8. An electronic device comprising:
 an enclosure defining an interior cavity of the electronic device, the enclosure including a cover assembly comprising:
 a cover member comprising a glass ceramic material; 
 an opaque polymer-based layer along a peripheral interior surface of the cover member; 
 an oxide-based layer between the cover member and the opaque polymer-based layer; and 
 a coupling agent between the oxide-based layer and the opaque polymer-based layer, and 
 
 a display, at least a portion of the display positioned under the cover member and within the interior cavity. 
 
     
     
       9. The electronic device of  claim 8 , wherein the coupling agent bonds with each of the oxide-based layer and the opaque polymer-based layer. 
     
     
       10. The electronic device of  claim 9 , wherein the coupling agent forms a chemical bond with at least one of the oxide-based layer and the opaque polymer-based layer. 
     
     
       11. The electronic device of  claim 9 , wherein the coupling agent is silane-based. 
     
     
       12. The electronic device of  claim 9 , wherein:
 the cover assembly defines an interphase region between the oxide-based layer and the opaque polymer-based layer; and 
 the coupling agent forms a distinct layer in the interphase region. 
 
     
     
       13. The electronic device of  claim 8 , wherein the oxide-based layer is a silicon oxide-based layer. 
     
     
       14. The electronic device of  claim 8 , wherein the oxide-based layer has a thickness from 2 nm to 30 nm. 
     
     
       15. An electronic device comprising:
 an enclosure including a cover assembly, the cover assembly defining an exterior surface of the electronic device and comprising:
 a glass ceramic cover member; 
 a polymeric layer positioned along an interior surface of the glass ceramic cover member; and 
 an adhesion layer comprising:
 an oxide-based layer positioned between the glass ceramic cover member and the polymeric layer and directly adhered to the glass ceramic cover member; and 
 a coupling agent directly adhered to each of the oxide-based layer and the polymeric layer. 
 
 
 
     
     
       16. The electronic device of  claim 15 , wherein:
 the electronic device further comprises a display; 
 the polymeric layer defines a central opening positioned over at least a portion of the display; 
 the oxide-based layer spans the central opening defined by the polymeric layer; 
 the adhesion layer is transparent to visible light; and 
 the display is viewable through the central opening. 
 
     
     
       17. The electronic device of  claim 15 , wherein the cover assembly defines a rear surface of the electronic device. 
     
     
       18. The electronic device of  claim 15 , wherein the polymeric layer has a thickness from 10 microns to 100 microns. 
     
     
       19. The electronic device of  claim 15 , wherein the coupling agent chemically bonds to the polymeric layer. 
     
     
       20. The electronic device of  claim 15 , wherein:
 the polymeric layer defines a first mounting surface; and 
 the enclosure further comprises:
 a housing member defining a second mounting surface; and 
 an adhesive coupling the first mounting surface and the second mounting surface.

Description:
CROSS REFERENCE TO RELATED APPLICATION(S) 
     This application is a non-provisional application of and claims the benefit of U.S. Provisional Patent Application No. 62/899,042, filed Sep. 11, 2019, and titled “Electronic Device with a Cover Assembly Having an Adhesion Layer,” and of U.S. Provisional Patent Application No. 62/994,616, filed Mar. 25, 2020, and titled “Electronic Device with a Cover Assembly Having an Adhesion Layer,” the disclosure of each of which is hereby incorporated by reference herein in its entirety. 
    
    
     FIELD 
     The described embodiments relate generally to use of an adhesion layer including one or more oxide materials to improve the adhesion strength between a cover member and a coating. More particularly, embodiments relate to electronic devices including an adhesion layer between an interior coating and a cover member including a glass ceramic material. 
     BACKGROUND 
     An interior surface of a cover glass for an electronic device may be coated to provide a decorative effect. For example, an opaque coating may be used to block one or more internal components of the electronic device from view. The opaque coating may be selectively applied to the cover glass to allow viewing of a display. 
     SUMMARY 
     The following disclosure is generally related to improving the adhesion between a coating and a cover member for an electronic device, thereby improving the durability of the electronic device. In particular, an adhesion layer as described herein may be used to improve the adhesion between a cover member including a glass ceramic material and the coating. The coating may be an interior coating, such as a polymer-based mask or other cosmetic coating. 
     In some embodiments, the adhesion layer comprises an oxide-based layer, such as a silicon oxide layer. The adhesion layer may further include a coupling agent such as a silane-based coupling agent. The adhesion layer is typically thin relative to the coating and may be less than 100 nm thick. 
     The disclosure provides an electronic device comprising a display and an enclosure including a cover assembly. The cover assembly is positioned over the display and comprises a cover member formed from a glass ceramic material, a cosmetic masking layer positioned along an interior surface of the glass ceramic cover member and defining an opening positioned over at least a portion of the display, and an adhesion layer including a silicon-based oxide and forming a bond between the glass ceramic material of the cover member and the cosmetic masking layer. 
     In addition, the disclosure provides an electronic device comprising an enclosure defining an interior cavity of the electronic device. The enclosure includes a cover assembly comprising a cover member comprising a glass ceramic material, an opaque polymer-based layer along a peripheral interior surface of the cover member, an oxide-based layer between the cover member and the opaque polymer-based layer, and a coupling agent between the oxide-based layer and the opaque polymer-based layer. The electronic device also comprises a display, at least a portion of the display positioned under the cover member and within the interior cavity. 
     Further, the disclosure provides an electronic device comprising an enclosure including a cover assembly. The cover assembly defines an exterior surface of the electronic device and comprises a glass ceramic cover member, a polymeric layer positioned along an interior surface of the glass ceramic cover member, and an adhesion layer. The adhesion layer comprises an oxide-based layer positioned between the glass ceramic cover member and the polymeric layer and directly adhered to the glass ceramic cover member and a coupling agent directly adhered to each of the oxide-based layer and the polymeric layer. 
    
    
     
       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. 1A  shows a front view of an example electronic device. 
         FIG. 1B  shows a rear view of the electronic device of  FIG. 1A . 
         FIG. 2  shows an example of a cover assembly. 
         FIG. 3  shows an additional example of a cover assembly. 
         FIG. 4  shows a detail view of a cover assembly including an adhesion layer. 
         FIG. 5  shows a detail view of an adhesion layer. 
         FIG. 6A  shows an example of a coupling additive. 
         FIG. 6B  shows an additional detail view of an adhesion layer. 
         FIG. 7  shows a partial cross-section view of a cover assembly coupled to a housing member. 
         FIG. 8  shows a partial cross-section view of a cover assembly coupled to another housing member. 
         FIG. 9  shows a detail view of a coupling structure between a cover member and a housing member. 
         FIG. 10  shows a flow chart of a process for making a cover assembly. 
         FIG. 11  shows a flow chart of an additional process for making a cover assembly. 
         FIG. 12  shows a block diagram of components of an electronic device. 
     
    
    
     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 an adhesion layer for improving the adhesion between a coating and a cover member for an electronic device. In some cases, the cover member comprises a glass ceramic material and the adhesion between the glass ceramic material and the coating in the absence of an adhesion layer may be less than for a conventional glass material. An adhesion layer as described herein may therefore improve the durability of the electronic device. The adhesion layer may also provide improved protection against entry of water or particles into the electronic device. 
     In some cases, the disclosure provides a cover assembly for an electronic device which includes an adhesion layer. By the way of example, the cover assembly comprises a cover member including a glass ceramic material, an interior coating, and an adhesion layer between the cover member and the interior coating. The adhesion layer may comprise an oxide material, which is typically in the form of a layer. The adhesion layer may further comprise a coupling agent. In some cases, the interior coating provides a cosmetic effect and may be referred to as a cosmetic coating. The interior coatings described herein typically comprise a polymer and may also comprise a colorant. 
     In addition, the disclosure provides an electronic device including the cover assembly described herein. The electronic device may include a display and in some cases the cover assembly may be provided over the display. Each of the cover member and the adhesion layer may be transparent to visible light. The coating may be opaque in order to mask at least a portion of an interior device component. In some cases, the coating may define an opening through which the display may be viewed. 
     The cover member and the cover assembly are typically coupled to another component of the enclosure. In some cases, a coupling structure may be formed between the cover member and a housing member of the enclosure, with the coupling structure defined by the adhesion layer, the interior coating layer, and an adhesive positioned between the interior coating layer and the housing member. 
     The disclosure also provides methods for making a cover assembly including an adhesion layer. In some cases, a method includes operations of forming an oxide-based layer on a surface of the cover member and applying a coating mixture including a coupling additive to the oxide-based layer. The coupling additive may serve as a precursor for the coupling agent molecules present in the adhesion layer. 
     These and other embodiments are discussed below with reference to  FIGS. 1A-12 . 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. 1A  shows a front view of an example electronic device  100  including a cover assembly  122  as described herein. The electronic device  100  may be a mobile telephone (also referred to as a mobile phone). In additional embodiments, the electronic device  100  may be a notebook computing device (e.g., a note book), a tablet computing device (e.g., a tablet), a portable media player, a wearable device, or another type of portable electronic device. The electronic device  100  may also be any other type of electronic product or device. 
     As shown in  FIG. 1A , the electronic device  100  comprises an enclosure  110  including the cover assembly  122 . The cover assembly  122  is positioned over a display assembly  160  and may define a transparent portion positioned over the display assembly  160  (indicated by the dashed line in  FIG. 1A ). The cover assembly  122  may at least partially define an external surface of the electronic device  100 , such as a front surface  102  of the electronic device. Typical cover assemblies described herein are thin, typically less than 5 mm in thickness. In some cases, a cover assembly may be less than 3 mm in thickness or less than 1 mm in thickness. 
     The cover assembly  122  may include a cover member  132  which comprises a glass ceramic material (examples of cover members are also shown in  FIGS. 2 and 3 ). In some cases, the cover member  132  may consist essentially of a glass ceramic material or may be formed from a glass ceramic material. Typically, the glass ceramic material includes a crystalline phase and an amorphous (glass) phase. The cover member may be a glass ceramic-based cover member including at least 50%, 60%, 70%, 80%, 90%, or 95% of the glass ceramic material. A cover member including at least 90% or more of the glass ceramic material may also be simply referred to as a glass ceramic cover member. The additional description of glass ceramic materials provided with respect to  FIG. 10  is generally applicable herein and, for brevity, is not repeated here. 
     The cover member may be generally flat or may be formed to have a curved profile (as shown in  FIGS. 2 and 3 ). In some cases, a cover member as described herein may be included in an all glass ceramic enclosure or an enclosure including combinations of glass ceramic and glass cover members. The enclosure may be multi-faceted. In such cases, the cover member may define one or more surfaces of the enclosure, such as a front surface and a side surface, a rear surface and a side surface, or a front surface, a side surface, and a rear surface. In some aspects, a cover member (such as the cover member  132 ) included in a cover assembly can have a thickness from about 0.1 mm to 2 mm, from 0.5 mm to 2 mm, from 0.2 mm to 1 mm, or from 100 microns to 500 microns. 
     The cover assembly  122  typically also includes one or more coatings. For example, an interior coating may be provided along an interior surface of the cover member  132 . In some cases, the interior coating may be used to obscure or mask at least a portion of an internal component of the electronic device. Other portions of the internal component, such as an active portion of a display, may be visible rather than masked. Interior coatings are illustrated and described in further detail with respect to  FIGS. 2-4 . That description is generally applicable herein and for brevity is not repeated here. The cover assembly  122  may also include an exterior coating, such as a smudge-resistant coating provided along an exterior surface of the cover assembly. 
     As previously described, an adhesion layer may be provided between the cover member  132  and at least a portion of a coating to increase the adhesion strength of the coating. The adhesion layer may comprise an oxide material, such as a silicon oxide. In some cases, the adhesion layer includes an oxide-based layer which may be thin relative to the cover member  132  and the coating (e.g., a cosmetic coating). The adhesion layer may further include a coupling agent which interacts with both the oxide material and the material of the coating. For example, the coupling agent may be silane-based. 
     As previously discussed, in some cases the adhesion layer may be provided between an interior surface of the cover member and at least a portion of an interior coating. In additional cases, an adhesion layer may also be provided between an exterior surface of the cover member and an exterior coating, such as a smudge-resistant coating. In some embodiments, the adhesion layer may be transparent to visible light. Adhesion layers are illustrated and described in further detail with respect to  FIGS. 2-5 and 6B-9 . That description is generally applicable herein and for brevity is not repeated here. 
     In some embodiments, a coupling structure is formed between the cover member  132  and a housing member  112  and the inclusion of the adhesion layer in the cover assembly increases the strength of the coupling structure and the durability of the electronic device  100 . As illustrated in  FIG. 9 , the coupling structure may include the adhesion layer, the coating, and an adhesive between the coating and the housing member. Additional features, such as a fastener or another type of engagement feature may also be used to couple the cover assembly  122  and the cover member  132  to the housing member  112 . 
     Generally, a housing member  112  of the enclosure  110  may include one or more metal members or one or more glass members. As shown in  FIG. 1A , the housing member  112  is formed from a series of metal segments ( 114 ,  116 ) that are separated by polymer or dielectric segments  115  that provide electrical isolation between adjacent metal segments. One or more of the metal segments ( 114 ,  116 ) may be coupled to internal circuitry of the electronic device  100  and may function as an antenna for sending and receiving wireless communication. The housing member  112  may at least partially define a side surface  106  of the electronic device  100 . The housing member  112  may be formed from a metal, a glass, a ceramic, a plastic, or a combination thereof. 
     The enclosure  110  may at least partially surround the display assembly  160 . The display assembly  160  includes a display and may also include a touch sensor, a force sensor, or a combination thereof. The display may be 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, and the like. A touch sensor may be configured to detect or measure a location of a touch along the exterior surface of the front cover assembly  122  while a force sensor may be configured to detect a force applied along the exterior surface. The touch sensor may be located between the cover assembly  122  and the display. Touch sensors, force sensors, and displays are described in more detail below with respect to  FIG. 12  and that description is generally applicable herein. 
     As shown in  FIG. 1A , the cover member  132  defines an opening  172  (which may also be referred to as a hole). In general, an opening may be provided in the cover member  132  or other transparent component to facilitate input to or output from a device component such as a microphone, a camera component, and the like. In the example of  FIG. 1A , the opening  172  may provide a speaker port for an earpiece of the electronic device  100 . Additional device components are described in more detail below with respect to  FIG. 12  and that description is generally applicable herein. 
       FIG. 1B  shows an example of a rear view of the electronic device  100  of  FIG. 1A . The enclosure  110  further includes a cover assembly  128 . The enclosure  110 , the housing member  112 , the metal segments  114  and  116 , and the polymer or dielectric segments  115  are as previously described for  FIG. 1A . The cover assembly  128  may define a rear surface  104  of the electronic device  100 . 
     The cover assembly  128  may include a cover member  138 . As shown in  FIG. 1B , the cover member  138  includes an opening  174  configured to surround a window  117  and one or more camera assemblies may be placed below the window  117 . The opening  174  is not limited to the shape shown in  FIG. 1B  and may be circular, square, or any other desired shape. In other embodiments, the cover member  138  may not include an opening or may include multiple openings. In some cases, the cover member  138  may be formed of similar materials to the cover member  132 . The cover member  138  may also be formed of glass, a polymeric material, a ceramic material, or combinations thereof. 
       FIG. 2  shows a cross-section view of a cover assembly  222  and a cover member  232 . For example, the cross-section may be taken along A-A of  FIG. 1A . As shown in  FIG. 2 , the cover assembly  222  includes a cover member  232  and a coating  242  disposed over an interior surface  236  of the cover member  232 . A coating disposed over an interior surface of the cover member, such as the coating  242 , may also be referred to herein as an interior coating. An adhesion layer (e.g., adhesion layer  450  of  FIG. 4 ) is provided between the cover member  232  and at least a portion of the coating  242 . The description of the adhesion layer provided with respect to the detail views of  FIGS. 4 and 5  is generally applicable herein and, for brevity, is not repeated here. 
     The coating  242  may have the form of a layer and may be referred to herein as a coating layer. In some cases, the coating  242  may be configured to provide a decorative or cosmetic effect and may be referred to as a cosmetic layer, a cosmetic coating layer, a decorative layer, or a decorative coating layer. For example, the coating  242  may be configured to impart a particular color to the electronic device. When the coating  242  is sufficiently translucent or opaque it may be used to provide a masking effect and may be referred to as a masking layer, a cosmetic masking layer, or a decorative masking layer. For example, a masking layer may have a transmittance less than a specified value (e.g., less than 50%, less than 40%, less than 30%, less than 20%, or less than 10%). In some cases, the transmittance may be integrated over the spectrum of visible light. As another example, a masking layer may have an optical density greater than a specified value. For example, the optical density of a masking layer  242  may be described by OD=log 10  (initial intensity/transmitted intensity) and may be greater than or equal to 1, greater than or equal to 2, or greater than or equal to 3. In some cases, the coating  242  need not provide a decorative effect. For example, the coating  242  may be substantially transparent or clear. 
     As shown in  FIG. 2  the coating  242  has the form of a layer having a thickness T c . The thickness T C  of the coating is not necessarily shown to scale. In some embodiments, the thickness T C  of the coating ranges from 10 microns to 100 microns, 15 microns to 75 microns, 20 microns to 60 microns, or 25 microns to 50 microns. In some embodiments, the thickness Tc of the coating is greater than 10 microns and less than 50 microns. The thickness Tc of the coating may vary from the express examples provided herein. 
     In some cases, the coating  242  may include sublayers. For example, the coating  242  may comprise from 1 to 100, from 1 to 50, from 1 to 25, from 1 to 10, or from 2 to 10 (sub)layers. When the coating comprises a plurality of sublayers, the sublayers typically form a stack. The sublayers may have substantially the same composition or may differ in composition. Each sublayer may have a thickness from about 2 microns to about 10 microns. A coating  242  including multiple sublayers may also be referred to herein as a multilayer assembly. 
     As shown in  FIG. 2 , the coating  242  extends along the interior surface  236  only in a peripheral portion  233  of the cover member. The coating  242  defines a width W 2  which is less than a lateral dimension L 2  of the cover member  232 . The interior surface  236  in the central portion  235  of the cover member  232  is free of the coating. Therefore, the coating  242  defines a central opening (corresponding to the portion of the interior surface  236  which is free of the coating). As illustrated in  FIG. 4 , the central opening may be placed over a portion of a display assembly. In some cases, the adhesion layer or at least a portion of the adhesion layer may be present on the portion of the interior surface  236  which is free of the coating  242 . For example, the oxide-based layer may span the central opening. 
     In some cases, the coating  242  comprises a polymer. The coating  242  may comprise at least 40%, 50%, 60%, or 70% of the polymer and may therefore be referred to as a polymer-based coating or a polymeric coating. When the coating further comprises a colorant, the polymer may act as a binder for the colorant. The colorant (e.g., a pigment) may be substantially dispersed in a matrix of the polymer. As examples, the polymer may be polyester-based, epoxy-based, urethane-based, or based on another suitable type of polymer or copolymer. The coating  242  may further comprise optional additives such as one or more extenders, diluents, polymerization initiators, and/or stabilizers. In some embodiments, the polymer has a cross-linked structure. When the coating includes multiple sublayers, the polymer of each of the sublayers may have a cross-linked structure. 
     The coating  242  may be opaque to visible light due at least in part to incorporation of a colorant. The thickness of the coating  242  and the number of layers/sublayers may be adjusted to obtain a desired level of opacity. In some cases, the coating  242  may serve as an opaque layer or a masking layer. 
     The colorant may comprise a dye, a pigment, or a combination thereof. Further, a colorant may comprise an organic material, an inorganic material, an organometallic material, or a hybrid material. Examples of inorganic pigments include, but are not limited to, carbon-based pigments (e.g., carbon black) and metal based pigments such as oxides (e.g., titanium dioxide, chromium oxide, iron oxides), sulfides, phosphates, and silicates (e.g., ultramarine). Examples of organic pigments include, but are not limited to, azo pigments and phtalocyanine pigments. Examples of organic dyes include, but are not limited to, azo dyes, anthraquinone dyes, and phtalocyanine dyes. In embodiments, the weight percentage of the colorant is from about 5 wt % to about 40 wt %. 
     In the example of  FIG. 2 , the exterior surface  234  in the peripheral portion  233  of the cover member  232  defines a curved profile. The interior surface  236  of the cover member  232  defines a substantially planar profile. For example, the interior surface  236  may be planar to within 25 microns, 20 microns, 15 microns, 10 microns, or 5 microns. The thickness of the cover member  232  is greater in the central portion  235  than in the peripheral portion  233 . The shape of the cover member  232  may be achieved by machining, molding, hot forming, or a combination thereof. 
     The example of  FIG. 2  is not limiting and the cover members and cover assemblies described herein may have a shape other than the shape shown in  FIG. 2 .  FIG. 3  shows an example of a cross-sectional view of a three-dimensional cover member  332  and cover assembly  322 . The coating  342  is disposed over an interior surface  326  of the cover member  332 . An adhesion layer is provided between the cover member  332  and at least a portion of the coating  342  (e.g., adhesion layer  450  of  FIG. 4 ). The description of the adhesion layer provided with respect to detail views of  FIGS. 4 and 5  is generally applicable herein and, for brevity, is not repeated here. 
     As shown in  FIG. 3 , the coating  342  extends along the interior surface  326  only in a peripheral portion  333  of the cover member  332 . The interior surface  326  in the central portion  335  of the cover member  332  is free of the coating  342 . In some cases, at least a portion of the adhesion layer may be present on the portion of the interior surface  326  which is free of the coating  342 . 
     In the example of  FIG. 3 , an end  337  of the peripheral portion  333  is not coplanar with a central portion  335  of the cover member  332 . By the way of example, the end  337  may define an angle with respect to a plane defined by the central portion  335 , such as an angle of 90 degrees or an angle from 80 degrees to 100 degrees. Each of the interior surface  326  and the exterior surface  324  define a curved profile and together the interior surface  326  and the exterior surface  324  define a curved side portion  352  of the cover member  332 . In some cases, the curved side portion  352  may function as a flange. 
     The coating  342  defines a width W 3  which is less than a lateral dimension L 3  of the cover member  332 . The central portion  335  is therefore free of the coating  342 . The placement of the coating  342  in  FIG. 3  is not limiting and in some cases the coating may extend onto the curved portion of the interior surface  326 . The thickness of the coating  342  may be as previously described for  FIG. 2  and, for brevity, that description is not repeated here. 
       FIG. 4  shows a detail view of an adhesion layer  450  between a cover member  432  and an interior coating  442  of a cover assembly  422 . For example,  FIG. 4  may be an example of detail  1 - 1  of  FIG. 2 . As illustrated in  FIG. 4 , the adhesion layer  450  comprises an oxide-based layer  452  and a coupling agent  454 . The oxide-based layer  452  and the coupling agent  454  are depicted schematically and are not necessarily drawn to scale. 
     The coupling agent  454  helps bond or couple the interior coating  442  to the oxide-based layer  452  by interacting with both the oxide-based layer  452  and the interior coating  442 . For example, the coupling agent  454  may be bonded to each of the oxide-based layer  452  and the interior coating  442 . The coupling agent  454  may be bonded to the oxide-based layer  452  and/or the interior coating  442  by a chemical bond, such a covalent bond or a hydrogen bond. For example, the interior coating  442  may include a polymer matrix which is chemically bonded to the coupling agent  454 . As another example, the coupling agent  454  may interact with the oxide-based layer  452  and/or the interior coating  442  by various types of intermolecular interactions and/or by mechanical interlocking. The coupling agent may be directly adhered to each of the oxide-based layer and the polymeric layer. 
     The coupling agent  454  may have the form of a plurality of individual molecules, of a network of interconnected molecules (as schematically shown in  FIG. 6B ), or a combination thereof. The coupling agent  454  may be silane-based and derived from a silane-based coupling additive. For example, the coupling agent  454  may include a silicon atom linked to one or more residues of moieties present in the coupling additive. Additional description of coupling additives and coupling agents is provided with respect to  FIGS. 6A and 6B . The description of coupling additives and coupling agents provided with respect to  FIGS. 6A and 6B  is generally applicable here and, for brevity, is not repeated here. 
     As shown in  FIG. 4 , the boundary between the oxide-based layer  452  and the interior coating  442  is not sharp, but defines an interphase region  474 . Typically, at least some of the coupling agent  454  is located in the interphase region  474 . The interphase region  474  may include a combination of molecules of the coupling agent  454  and molecules of the interior coating  442 . When the molecules of the interior coating  442  interpenetrate with the coupling agent  454 , the coupling agent  454  and the adhesion layer  450  may be between the cover member  432  and at least a portion of the interior coating  442 . In some cases, the interphase region  474  may have a thickness from about 0.1 nm to about 10 nm or from about 0.2 nm to about 5 nm. 
     The oxide-based layer  452  of the adhesion layer  450  may contact the cover member  432  at an interface region  472 . In some cases, the cover member  432  may be directly adhered to the oxide-based layer  452 . For example, atoms of the cover member  432  may interact with atoms of the oxide-based layer  452  to produce adhesion of the oxide-based layer  452  to the cover member  432 , such as through chemical bonds. As an additional example, the boundary between the cover member  432  and the oxide-based layer  452  may be less sharp than is shown in  FIG. 4  and may be an interphase region. 
     The oxide-based layer  452  may be thin relative to the cover member  432  and the interior coating  442 . For example, the oxide-based layer  452  may have a thickness from 2 nm to 50 nm, from 5 nm to 20 nm, or from 10 nm to 30 nm. In some cases, the adhesion layer  450  may be transparent to visible light. For example, the adhesion layer  450  may transmit at least 80%, 90%, or 95% of light in the visible spectrum. 
     The strength of the coupling (or adhesion strength) between the cover member  432  and the coating  442  may be measured by various means. For example, the adhesion strength may be measured by a scrape test (e.g., ASTM D2197), a tape test (e.g., ASTM D3359), or a pull-off test (e.g., ASTM D4541). The adhesion strength between the cover member  432  and the coating  442  when the adhesion layer  450  is included may be greater than the adhesion strength between the cover member  432  and the coating  442  when the adhesion layer  450  is omitted. In some cases, the adhesion strength between the cover member  432  and the coating  442  when the adhesion layer  450  is included may be at least 25% greater, at least 50% greater, at least 75% greater, or at least 100% greater than the adhesion strength between the cover member  432  and the coating  442  when the adhesion layer  450  is omitted. 
     The protection provided by the electronic device as a whole against entry of water or particles may be measured by various ingress protection tests. For example, the IEC 60529 IP testing standard can be used to determine various ratings for liquids such as water. Such ratings can be used to characterize the extent to which the electronic device is waterproof. 
     The adhesion layer typically comprises an oxide material, such as a silicon oxide, a metal oxide, an alkaline earth oxide, or the like. As shown in  FIG. 4 , the adhesion layer includes an oxide-based layer. An oxide-based layer may comprise a relatively large amount of one or more oxide materials, such as at least 50%, 60%, 70%, 80%, 90%, or 95% by weight of the oxide material(s). An oxide-based layer including a relatively high amount of the one or more oxide materials, such as at least 90%, 95%, or 98% by weight of the oxide material(s) may be simply referred to herein as an oxide layer. Relatively small amounts of other elements, such as carbon, hydrogen, nitrogen, and the like may be present in the oxide-based layer as residue(s) from the process for forming the oxide-based layer. For example, in some cases the amount of these residual elements is less than 10%, 5%, or 2%. The oxide-based layer may have an amorphous structure, a crystalline structure, or a combination thereof. 
     In some cases, the oxide-based layer may predominantly comprise a silicon oxide, such as at least 50%, 60%, 70%, 80%, 90%, 95%, or 98% of the silicon oxide. An oxide-based layer including a relatively high amount of silicon oxide, such as at least 90%, 95%, or 98% by weight of silicon oxide may be simply referred to herein as a silicon oxide-based layer or as a silicon oxide layer. The silicon oxide may be characterized by the formula SiO x , where x may range from about 0.6 to about 2.0, from 1.0 to about 2.0, or 1.5 to 2.0. In some cases, x may be about 2.0. When x is less than 2, the silicon oxide may be referred to as being silicon rich. 
     In some cases, the oxide-based layer  452  comprises a mixed oxide and may be referred to as a mixed oxide-based layer. For example, the oxide-based layer  452  may comprise a mixed oxide which includes silicon and one or more metals in combination with oxygen. For example, the mixed oxide may comprise aluminum and/or lithium as well as silicon when the glass ceramic material is a lithium aluminosilicate material. When the amount of silicon exceeds the amount of the other metal(s) present in the oxide and the amount of residual elements in the oxide-based layer is relatively small, the mixed oxide may be referred to as a silicon-based oxide and the oxide-based layer may be referred to as a silicon-based oxide layer. As an additional example, the mixed oxide may also comprise zirconium. In some cases, the composition of the oxide layer may be described for convenience in terms of relative ratios of the oxide constituents even though the oxide may be substantially uniform in composition. 
     In some cases, the oxide-based layer  452  may be substantially uniform in composition. In other cases, the oxide-based layer  452  may vary in composition from the interface region  472  to the interphase region  474 . For example, the composition of the oxide-based layer  452  near the interphase region  474  may be selected to have a relatively high amount of silicon and may approach, or substantially match the composition of a silicon oxide. A combination of a relatively high amount of silicon with oxygen near the interphase region  474  may facilitate adhesion between the coupling agent  454  and the oxide-based layer  452 . The composition of the oxide-based layer  452  near the interface region  472  may be selected to more closely match the composition, the thermal expansion and/or another property of the glass ceramic material. In some cases, the composition of the oxide-based layer may substantially match the composition of the glass ceramic material. For example, a mixed oxide-based layer may include a greater amount of the metal (e.g., aluminum) near the interface region  472  than near the interphase region  474 . 
     In some embodiments, an oxide-based layer  452  may include a substantially continuous variation in composition between the region  472  and the region  474 . For example, the oxide-based layer  452  may be a graded coating (or gradient coating). In additional embodiments, an oxide-based layer may include sublayers which differ in composition.  FIG. 5  depicts an example of a cover assembly  522  where the oxide-based layer  552  includes two sub-layers  552   a  and  552   b.  The sublayers  552   a  and  552   b  may differ in composition and define an interface region  553  between the sublayers. For example, the sublayer  552   a,  which is adjacent the interface region  572  between the oxide-based layer  552  and the cover member  532 , may have a lower silicon content and a higher metal content than the sublayer  552   b.    
     The composition and/or the structure of the oxide-based layer  452  or  552  may depend at least in part on the process by which it is made. The description of processes for making oxide-based layers provided with respect to  FIG. 10  is generally applicable herein and, for brevity, will not be repeated here. 
       FIG. 6A  shows an example of a coupling additive  690  and  FIG. 6B  shows a detail view of an example of a coupling agent  654 . For example,  FIG. 6B  may be an example of detail  2 - 2  of  FIG. 4  and is greatly enlarged to show the coupling agent  654 . As described in more detail with respect to  FIG. 10 , the coupling agent  654  may be formed by applying a coating mixture including a coupling additive to the oxide-based layer and then forming the coating (e.g., a decorative coating). 
     In some cases, the coupling additive  690  is a silane-based coupling additive that includes four moieties chemically bonded to a silicon atom, as schematically shown in  FIG. 6A . In general, the coupling additive  690  may include one or more functional groups  692  which interact with the oxide-based layer  652  or hydroxyl groups formed on the oxide-based layer. The functional groups  692  may be hydrolyzable. In the example of  FIG. 6A , the coupling additive  690  includes three functional groups  692  which are shown as —O—R, where R is an alkyl group (e.g., methyl or ethyl). The coupling additive  690  as shown in  FIG. 6A  is therefore an alkoxy silane coupling additive. 
     In general, the coupling additive  690  also includes one or more functional groups  694  which interact with the polymer-based coating (e.g., the polymer-based coating  642  of  FIG. 6B ). In the example of  FIG. 6A , the coupling additive  690  includes a functional group  694  which is shown as an organofunctional group X. The organofunctional group X may include a reactive group that forms a bond with a monomer or resin in a coating mixture used to form the coating. Suitable reactive groups include, but are not limited to, vinyl groups, epoxy groups, amino groups, methacryloxy groups, and the like. The functional group  694  may be chemically bonded to the silicon atom by a spacer  696 , which may include from 3 to 10 carbon atoms (e.g., the spacer  696  may include a hydrocarbon chain). 
       FIG. 6B  shows an example of a coupling agent  654  in an interphase region  674  between the oxide layer  652  and the coating  642 . For example, the coupling agent  654  may be derived from the coupling additive  690  of  FIG. 6A . For simplicity, the oxide-based layer  652  and the coating  642  are shown generically without the details of their connection to the coupling agent. Because the coupling agent  654  is derived from the coupling additive, the chemical structure of the coupling agent  654  is typically not identical to that of the coupling additive  690 . In some cases, the mechanism of the interaction between the functional groups  692  and the oxide material(s) of the oxide-based layer  652  and/or the mechanism of the interaction between the functional groups  694  and the material of the coating  642  may chemically modify the coupling additive  690 . For example, the coupling agent  654  may comprise a residue of the functional groups  692  and/or  694 . 
     As one example, the chemical structure of coupling agent  654  may be produced in part by hydrolyzation of the alkoxy groups  692 . The resulting silanol groups can coordinate with hydroxyl groups on the surface of the oxide-based layer an elimination of water can form a chemical bond between the coupling agent  654  and the oxide-based layer  652 . In addition, a coupling agent  654  having a network structure can be formed by condensation between adjacent coupling additive molecules. The network may form a distinct layer in the interphase region. Interpenetration of the molecules of the coating into such a network can also contribute to the interaction between the coupling agent  654  and the coating  642 . Further, reaction of the functional group  694  with a monomer or resin of the coating mixture can form a chemical bond between the coupling agent  654  and the polymer of the coating. The example of  FIG. 6B  is not limited to the type of coupling additive and interactions shown. 
       FIG. 7  shows a partial cross-section view of an electronic device  700 . As shown in  FIG. 7 , the cover assembly  722  includes a cover member  732  and a coating  742  along a portion of an interior surface  736  of the cover member  732 . The coating  742  defines a width W 4  which is less than a lateral dimension of the cover member  732 . In some cases, the width W 4  may be from about 0.5 mm to about 5 mm, or from 1 mm to about 3 mm. An adhesion layer is provided between the cover member  732  and at least a portion of the coating  742 . The description of the adhesion layer provided with respect to detail views of  FIGS. 4-6B  is generally applicable herein and, for brevity, is not repeated here. The cover member  732  further defines an exterior surface  734 . 
     The electronic device  700  further includes a display assembly  760  within an interior cavity  705  of the electronic device. The display assembly  760  includes a display and may also include a touch sensor, a force sensor, or a combination thereof. The display assembly  760  may be similar to the display assembly  160  of  FIG. 1A  and, for brevity, that description is not repeated here. 
     As shown in  FIG. 7 , the display assembly  760  is positioned below the cover member  732 . In addition, the display assembly  760  is positioned so that at least a portion of the coating  742  is between the cover member  732  and the display assembly  760 . In other words, at least a portion of the display assembly  760  is underneath the coating  742  (along the Z direction). When the coating  742  is opaque, the coating  742  may thus obscure or mask this portion of the display assembly  760  from view from above (through the cover member  732 ). The display assembly  760  may be coupled to the cover assembly  722  with an adhesive  772 . In particular, the display assembly  760  may be coupled to a portion of the interior surface  736  of the cover member  732  which is free of the coating  742  (although this portion of the interior surface  736  may include at least a portion of the adhesion layer, such as an oxide-based layer). The adhesive  772  may be a polymer-based adhesive, such as a pressure sensitive adhesive, and may be optically clear. 
     As shown in  FIG. 7 , the cover assembly  722  may be coupled to a housing member  712  of the enclosure  710 . In some embodiments, a coupling structure  711  (which may also be referred to as a joint) is formed between the cover member  732  and the housing member  712 . The coupling structure  711  may include the adhesion layer (e.g., the adhesion layer  950  shown in the detail view of  FIG. 9 ), the coating  742 , and an adhesive  774  between the coating  742  and the housing member  712 . In the example of  FIG. 7 , the adhesive  774  contacts the coating  742  and a ledge  713  formed in the housing member  712 . In some cases, the coating  742  may be described as defining a first mounting surface; and the housing member  712  (and the ledge  713 ) may be described as defining a second mounting surface, with the adhesive  774  coupling the first mounting surface and the second mounting surface. In some cases, the adhesive  774  may include a dye or pigment. 
     As previously described, an adhesion layer as described herein can provide improved adhesion strength between a cover member comprising a glass ceramic material and a coating. In addition, a coupling structure including an adhesion layer as described herein can provide a higher resistance to entry of water or other fluids than when an adhesion layer is omitted. Methods for measuring adhesion strength and resistance to entry of fluids or particles were previously described with respect to  FIG. 4  and, for brevity, that description is not repeated here. 
       FIG. 8  shows a partial cross-section view of an electronic device  800 . As shown in  FIG. 8 , the cover assembly  822  includes a cover member  832  and a coating  842  along an interior surface  836  of the cover member  832 . The cover member  832  further defines an exterior surface  834 . 
     In the example of  FIG. 8 , the enclosure  810  includes a first housing member  812  and a second housing member  817 . The first housing member  812  may be similar to housing members  112  and  712  of  FIGS. 1 and 7  and, for brevity, that description is not repeated here. In some cases, the second housing member  817  may be configured to function as a holder or tray for the cover assembly  822 . The second housing member  817  may have a dimension in each of the X and the Z directions that is less than that of the first housing member  812 . The enclosure  810  defines an interior cavity  805  of the electronic device  800 . The display assembly  860  is positioned within the interior cavity and coupled to the cover member  832  by an adhesive  872 . 
     As shown in  FIG. 8 , the cover assembly  822  may be coupled to the second housing member  817 . In some embodiments, a coupling structure  811  is formed between the cover member  832  and the second housing member  817 . The coupling structure  811  may include the adhesion layer (e.g., the adhesion layer  950  shown in the detail view of  FIG. 9 ), the coating  842 , and an adhesive  874  between the coating  842  and the second housing member  817 . The second housing member  817  may define a ledge  818  configured to receive the cover assembly  822 . As shown in  FIG. 8 , the adhesive  874  contacts the coating  842  and the ledge  818 . In some cases, the adhesive  874  may include a dye or pigment. 
     As shown in  FIG. 8 , the second housing member  817  is coupled to the first housing member with an adhesive  876 . The second housing member  817  may be coupled to a ledge  813  defined by the first housing member  812 . In some cases, the second housing member  817  may comprise a polymer or may be polymer-based. In the example of  FIG. 8 , the second housing member  817  defines a recess  819  and a portion of the display assembly  860  extends into the recess  819 . The positioning of the display assembly  860  with respect to the cover member  832  and the coating  842  in  FIG. 8  is similar to that shown in  FIG. 7  and, for brevity, those details are not repeated here. 
       FIG. 9  shows a detail view of a coupling structure  911  between a cover member  932  and a housing member  912  of an electronic device  900 . The coupling structure is defined by an adhesion layer  950 , a coating  942 , and an adhesive  974 . The coupling structure  911  comprises at least a portion of the adhesion layer  950  and the coating  942 , as well as the adhesive  974 . The cover member  932 , the housing member  912 , the adhesion layer  950 , the coating  942 , and the adhesive  974  may be similar to the housing members, adhesion layers, coatings, and adhesives previously described with respect to  FIGS. 1A-8  and, for brevity, that description is not repeated here. 
       FIG. 10  shows a flow chart of a process  1000  for making a cover assembly. The cover assembly includes a cover member that comprises a glass ceramic material. As referred to herein, a glass ceramic material comprises one or more crystalline phases. Therefore, the glass ceramic is at least partially crystallized. The glass ceramic may further comprise an amorphous (glass) phase. In some cases, an entirely of the cover member comprises the glass ceramic material. In other cases, the glass ceramic material may be allocated to selected regions of the cover member. 
     As examples, the crystalline phase in the at least partially crystallized glass ceramic comprises from 20% to 90% , from 30% to 90%, from 40% to 90%, from 50% to 90%, from 60% to 90%, from 70% to 90%, from 75% to 95%, or greater than 80% of the at least partially crystallized glass ceramic by volume. The amorphous phase and the crystalline phase together may comprise 90% to 100% of the volume of the glass ceramic cover member. In some cases, the cover member includes a sufficiently high volume percentage of the crystalline phase to be described as a glass ceramic cover member. For example, a glass ceramic cover member may include from 50% to 90%, from 60% to 90%, from 70% to 90%, from 75% to 95%, or greater than 80% of the crystalline phase by volume. Typically, at least some of the crystalline phase (crystals) is located at one or more surfaces of the cover member. 
     By the way of example, the glass ceramic may be an alkaline silicate, an alkaline earth silicate, an aluminosilicate, a boroaluminosilicate, a perovskite-type glass ceramic, a silicophosphate, an iron silicate, a fluorosilicate, a phosphate, or another glass ceramic composition system. In some embodiments, the glass ceramic portion comprises an aluminosilicate glass ceramic or a boroaluminosilicate glass ceramic. As used herein, an aluminosilicate glass ceramic includes the elements aluminum, silicon, and oxygen, but may further include other elements. Similarly, a boroaluminosilicate glass ceramic includes the elements boron, aluminum, silicon, and oxygen, but may further include other elements. Aluminosilicate and boroaluminosilicate glass ceramics may further include monovalent or divalent ions which compensate charges due to introduction of aluminum ions in the glass ceramic. For example, an alkali aluminosilicate may include alkali metal ions which compensate for the inclusion of aluminum ions in the glass ceramic. 
     A lithium aluminosilicate (LAS) glass ceramic may be formed from a lithium aluminosilicate glass. For example, the lithium aluminosilicate glass may comprise from 60 wt % to 90 wt % SiO 2 , from 5 wt % to 30 wt % Al 2 O 3 , and from 2 wt % to 15 wt % Li 2 O. The lithium aluminosilicate glass may also comprise a relatively small amount (e.g., a few percent by weight) of a nucleating agent such as TiO 2 , ZrO 2 , and/or SnO 2 . The lithium aluminosilicate glass may also comprise a relatively small amount of one or more alkaline earth oxides or one or more alkali metal oxides other than lithium oxide. Lithium aluminosilicate glasses can form several types of crystals, including β quartz solid solution crystals, β spodumene solid solution crystals, and keatite solid solution crystals. The resulting crystals may have a coefficient of thermal expansion which is close to zero or even less than zero. The crystals may be small enough so that the cover member is substantially transparent to visible radiation. For example, the cover member may have a transmittance of at least 75%, 80%, 90%, or 95% for light in the visible spectrum. In addition, the cover member may have a limited amount of transmissive haze. The transmissive haze may relate to the amount of light subject to wide angle scattering (e.g., greater than 2.5 degrees) and may be measured according to ASTM or ISO standards. As non-limiting examples, the transmissive haze may be measured using a haze-gard i device available from BYK or a GC 5000L variable photometer available from Nippon Denshoku. The transmissive haze may be measured for the cover assembly or glass cover member as removed from the electronic device. In some cases, the transmissive haze may be less than or equal to about 40%, less than or equal to about 30%, less than or equal to 20%, less than or equal to 10%, less than or equal to 5%, such as less than 2%, less than or equal to 1.5%, or less than or equal to 1%. When a hazy effect is desired, the transmissive haze may be greater than or equal to about 50%, greater than or equal to about 60%, or greater than or equal to about 70%. 
     In some embodiments, the glass ceramic material is ion-exchangeable and the cover member comprising the glass ceramic material is chemically strengthened through an ion-exchange operation. The ion-exchange operation may comprise an operation of exchanging first ions in a surface region of the cover member with second ions. The first ions have a first size and the second ions have a second size larger than the first size. The first ions may be exchanged for the second ions by immersing the member in a bath comprising the second ions. For example, the exchange of ions may form an ion exchange layer which extends to an exchange depth less than a thickness of the glass portion of the member. Each of the first ions and the second ions may be alkali metal ions. In embodiments, lithium ions may be exchanged with sodium or potassium ions and/or sodium ions may be exchanged with potassium ions. 
     After an ion-exchange operation, the glass ceramic material typically includes an ion exchanged region and a region which has not been substantially ion exchanged. For example, the ion-exchanged region may be depleted with respect to first alkali metal ions and enriched with respect to second alkali metal ions. The ion exchanged region may extend to depth D from a surface of the cover member. The ion exchange may occur in the glass phase or in some cases may occur in the ceramic phase or a combination of the glass phase and the ceramic phase. In some examples, an ion-exchanged region may be formed along front and rear surfaces of the cover member, as well as side surfaces of the cover member. 
     The exchange of larger alkali metal ions for smaller alkali metal ions can create a compressive stress region in the ion-exchanged region. The compressive stress region can extend to a depth of layer (DoL) from the surface of the cover member. When ion-exchanged regions are formed from opposing surfaces of the cover member, a tensile stress region is typically formed between the compressive stress regions. 
     As shown in  FIG. 10 , the process  1000  includes an operation  1002  of forming an oxide-based layer on the cover member. For example, the oxide-based layer is formed on an interior surface of the cover member (facing the interior cavity of the enclosure). In some cases, a substantial entirety of the interior surface of the cover member may be covered by the oxide-based layer. As previously discussed, the oxide-based layer may have a thickness from 2 nm to 50 nm, from 5 nm to 20 nm, or from 10 nm to 30 nm. 
     The oxide-based layer may be formed using a chemical deposition technique or a physical vapor deposition technique. Chemical deposition techniques include, but are not limited to, chemical vapor deposition techniques and sol-gel techniques. Physical deposition techniques include, but are not limited to, evaporation techniques and sputtering techniques. In some embodiments, the temperatures used in the operation  1002  are kept sufficiently low that ion-exchanged region(s) previously formed within the cover member are not significantly affected (e.g., by diffusion of ions). For example, plasma-enhanced chemical vapor deposition (PECVD), sputter deposition, or sol-gel techniques may be used at temperatures less than about 300° C. 
     In some cases, the technique used to form the oxide-based layer may influence the composition and/or the structure of the oxide-based layer. For example, oxide-based layers formed using a sol-gel process may include residual carbon from the precursors used in the oxide material. In some cases, an oxide-based layer formed using a sol-gel process may also have a lower density (greater porosity) than an oxide-based layer formed using a physical vapor deposition process. The description of oxide-based layer compositions provided with respect to  FIG. 4  is generally applicable herein, and, for brevity, is not repeated here. 
     In some cases, the cover member may be treated before the oxide-based layer is formed. For example, the cover member may be cleaned and/or plasma treated before the oxide-based layer is deposited. In addition, the cover member may be polished or otherwise textured to produce a desired level of roughness before the oxide-based layer is deposited. For example, the amplitude (e.g., root mean square height Sq) of the roughness may be from 2 nm to 2 microns, from 2 nm to 100 nm, from 5 nm to 200 nm, or from 10 nm to 300 nm. 
     As shown in  FIG. 10 , the process  1000  includes an operation  1004  of applying a coating mixture to the oxide-based layer. The coating mixture may include a polymerizable component such as a monomer, an oligomer, a prepolymer, or combinations thereof. The polymerizable component may include an ester group, an epoxy group, a urethane-group, or the like. The coating mixture also includes a coupling additive. Suitable coupling additives include, but are not limited to, silane-based coupling additives. In some cases, the silane-based coupling additive is an alkoxy silane such as a dialkoxy or trialkoxy silane. An example of a trialkoxy silane coupling additive is shown in  FIG. 6A . The alkoxy silane may be a methoxy or ethoxy silane. The coating mixture may also include one or more additional additives such as a colorant, an extender, a diluent, a polymerization initiator, or a stabilizer. 
     The process  1000  further includes an operation  1006  of forming a coating layer on the oxide-based layer with the coupling agent in the interphase region. During operation  1006  at least a portion of the coupling additive may segregate to the surface of the oxide-based layer and interact with the oxide-based layer. The coupling additive may also interact with the polymerizable components of the coating mixture as described in further detail with respect to  FIGS. 6A and 6B . As previously described, the coupling additive may be modified by these interactions, thereby forming a coupling agent which differs in chemical structure from the coupling additive. 
     The operation  1006  also typically includes polymerizing one or more polymerizable components of the coating mixture to form the polymer of the coating layer. For example, the polymerizable component(s) may include a monomer, an oligomer, or combinations thereof. The polymerization of the polymerizable components may be assisted by heat, light, or the like. 
     In some cases, the process  1000  may also include an operation of forming an additional coating, such as an anti-reflective coating and/or a smudge-resistant coating on an exterior surface of the cover member. For example, the smudge-resistant coating may include a hydrophobic or oleophobic coating such as a fluoropolymer coating. The coating(s) on the exterior surface may be formed after the coating(s) on the interior surface. 
     The description of glass ceramic materials, oxide-based layers, coupling additives, and coatings provided herein with respect to  FIG. 10  applies more generally to the cover assemblies described herein, including at least the cover assemblies of  FIGS. 1A-9 . 
       FIG. 11  is a flow chart of a process  1100  for making a cover assembly. The process  1100  includes an operation  1102  of forming an oxide-based layer on the cover member. The process  1100  also includes an operation  1104  of applying a first coating mixture to the oxide-based layer. The process  1100  further includes an operation  1106  of forming a first coating layer on the oxide-based layer. Operations  1102 ,  1104 , and  1106  may be similar to operations  1002 ,  1004 , and  1006  of process  1000  and for brevity that description is not repeated here. 
     The process  1100  further includes an operation  1108  of applying a second coating mixture to the first coating layer. In some cases the second coating mixture need not include the coupling additive and therefore may be different than the first coating mixture. In addition, the process  1100  includes an operation  1110  of forming a second coating layer. The operation  1110  typically includes polymerizing the polymerizable components of the second coating mixture to form the polymer of the second coating layer. The polymerizable component, additives, and polymerization conditions may be similar to those described with respect to  FIG. 9  and for brevity that description is not repeated here. Operations  1108  and  1110  may be repeated to form additional coating layers as desired. 
       FIG. 12  shows a block diagram of a sample electronic device that can incorporate a cover assembly as described herein. The schematic representation depicted in  FIG. 12  may correspond to components of the devices depicted in  FIG. 1A-11  as described above. However,  FIG. 12  may also more generally represent other types of electronic devices with cover assemblies as described herein. 
     In embodiments, an electronic device  1200  may include sensors  1220  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  1208  may be turned off, disabled, or put in a low energy state when all or part of the viewable area of the display  1208  is blocked or substantially obscured. As another example, the display  1208  may be adapted to rotate the display of graphical output based on changes in orientation of the device  1200  (e.g., 90 degrees or 180 degrees) in response to the device  1200  being rotated. 
     The electronic device  1200  also includes a processor  1206  operably connected with a computer-readable memory  1202 . The processor  1206  may be operatively connected to the memory  1202  component via an electronic bus or bridge. The processor  1206  may be implemented as one or more computer processors or microcontrollers configured to perform operations in response to computer-readable instructions. The processor  1206  may include a central processing unit (CPU) of the device  1200 . Additionally, and/or alternatively, the processor  1206  may include other electronic circuitry within the device  1200  including application specific integrated chips (ASIC) and other microcontroller devices. The processor  1206  may be configured to perform functionality described in the examples above. 
     The memory  1202  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  1202  is configured to store computer-readable instructions, sensor values, and other persistent software elements. 
     The electronic device  1200  may include control circuitry  1210 . The control circuitry  1210  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  1210  may receive signals from the processor  1206  or from other elements of the electronic device  1200 . 
     As shown in  FIG. 12 , the electronic device  1200  includes a battery  1214  that is configured to provide electrical power to the components of the electronic device  1200 . The battery  1214  may include one or more power storage cells that are linked together to provide an internal supply of electrical power. The battery  1214  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  1200 . The battery  1214 , via power management circuitry, may be configured to receive power from an external source, such as an alternating current power outlet. The battery  1214  may store received power so that the electronic device  1200  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  1200  includes one or more input devices  1218 . The input device  1218  is a device that is configured to receive input from a user or the environment. The input device  1218  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  1218  may provide a dedicated or primary function, including, for example, a power button, volume buttons, home buttons, scroll wheels, and camera buttons. 
     The device  1200  may also include one or more sensors  1220 , such as a force sensor, a capacitive sensor, an accelerometer, a barometer, a gyroscope, a proximity sensor, a light sensor, or the like. The sensors  1220  may be operably coupled to processing circuitry. In some embodiments, the sensors  1220  may detect deformation and/or changes in configuration of the electronic device and be operably coupled to processing circuitry which controls the display based on the sensor signals. In some implementations, output from the sensors  1220  is used to reconfigure the display output to correspond to an orientation or folded/unfolded configuration or state of the device. Example sensors  1220  for this purpose include accelerometers, gyroscopes, magnetometers, and other similar types of position/orientation sensing devices. In addition, the sensors  1220  may include a microphone, an acoustic sensor, a light sensor, an optical facial recognition sensor, or other types of sensing device. 
     In some embodiments, the electronic device  1200  includes one or more output devices  1204  configured to provide output to a user. The output device  1204  may include a display  1208  that renders visual information generated by the processor  1206 . The output device  1204  may also include one or more speakers to provide audio output. The output device  1204  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  1200 . 
     The display  1208  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  1208  is a liquid-crystal display or an electrophoretic ink display, the display  1208  may also include a backlight component that can be controlled to provide variable levels of display brightness. If the display  1208  is an organic light-emitting diode or organic electroluminescent-type display, the brightness of the display  1208  may be controlled by modifying the electrical signals that are provided to display elements. In addition, 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  1218 . 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  1200 . 
     The electronic device  1200  may also include a communication port  1212  that is configured to transmit and/or receive signals or electrical communication from an external or separate device. The communication port  1212  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  1212  may be used to couple the electronic device to a host computer. 
     The electronic device  1200  may also include at least one accessory  1216 , such as a camera, a flash for the camera, or other such device. The camera may be included in a camera assembly. The camera may be connected to other parts of the electronic device  1200  such as the control circuitry  1210 . 
     As used herein, the terms “about,” “approximately,” “substantially,” “substantially match,” “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. 
     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: 20200522
Publication Date: 20220308
Grant Date: 20220308
Priority Date: 20190911
Inventors: ROGERS, MATTHEW S.
MITTAL, MANISH
GIACHINO, MARTA M.
KAMEI, SAWAKO
Assignee: APPLE INC
CPC Classifications: [{"code": "H04M1/026", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1637", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1609", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B1/14", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04M1/0202", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/0283", "inventive": false, "first": false, "tree": "[]"}, {"code": "G06F1/1656", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04M1/0283", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B1/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C10/0027", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1609", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B1/14", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 74850426