PATENT DOCUMENT

Publication Number: US-11897809-B2
Application Number: US-202017109887-A
Country: US
Kind Code: B2

Title: Electronic devices with textured glass and glass ceramic components

Abstract:
Electronic devices including a textured component such as a cover member positioned over one or more components of the electronic device. Different surface regions of the textured component may be textured differently in order to provide optical contrast. For example, differently textured surface regions may differ in gloss, translucency, or both. In some cases the cover member defines a protruding feature and a surface region of the protruding feature is textured differently than an adjacent surface region.

Claims:
What is claimed is: 
     
       1. An electronic device comprising:
 a display; 
 an enclosure at least partially surrounding the display and comprising:
 a front cover assembly including a front member positioned over the display; and 
 a rear cover assembly including a chemically strengthened rear member, the chemically strengthened rear member defining:
 a base portion defining a base surface region; and 
 a feature protruding with respect to the base surface region and defining a surface region having a texture comprising:
 a mean pitch from 10 microns to 40 microns, and 
 a root mean square slope from 0.1 to 0.75; and 
 
 
 
 a camera assembly including a camera module positioned at least partially in a hole formed through the feature. 
 
     
     
       2. The electronic device of  claim 1 , wherein:
 the base surface region of the chemically strengthened rear member has a first gloss value greater than or equal to 100 gloss units as measured at an angle of 60 degrees; and 
 the surface region of the chemically strengthened rear member has a second gloss value less than 10 gloss units as measured at an angle of 60 degrees. 
 
     
     
       3. The electronic device of  claim 1 , wherein the mean pitch is greater than 20 microns and less than or equal to 40 microns. 
     
     
       4. The electronic device of  claim 1 , wherein the surface region has a root mean square height from 0.75 microns to 5 microns. 
     
     
       5. The electronic device of  claim 1 , wherein:
 the chemically strengthened rear member comprises at least one of a glass or a glass ceramic; and 
 the texture of the surface region is formed by a grinding operation followed by an etching operation. 
 
     
     
       6. The electronic device of  claim 1 , wherein:
 the hole formed through the feature is a first hole; and 
 the camera assembly further comprises a sensor module positioned at least partially within a second hole formed through the feature. 
 
     
     
       7. The electronic device of  claim 1 , wherein the rear cover assembly further comprises an internal coating that defines a color visible along the base surface region and the surface region. 
     
     
       8. An electronic device comprising:
 an enclosure including a cover assembly comprising:
 a glass member defining:
 a first exterior surface region having a first gloss value greater than 90 gloss units as measured at 60 degrees and defining a first texture having a first root mean square height less than 0.5 microns; and 
 a second exterior surface region having a second gloss value less than 10 gloss units as measured at 60 degrees and defining a second texture having:
 a second root mean square height from 1 micron to 5 microns; and 
 a mean pitch from 10 microns to 40 microns; and 
 
 
 a coating disposed along an interior surface of the glass member. 
 
 
     
     
       9. The electronic device of  claim 8 , wherein:
 the glass member further defines a feature that protrudes with respect to the first exterior surface region and a set of through-holes that extend through the feature; 
 the feature defines the second exterior surface region; and 
 the electronic device further comprises a camera assembly comprising:
 a first camera module extending into a first through-hole of the set of through-holes; 
 a second camera module extending into a second through-hole of the set of through-holes; 
 an illumination module extending into a third through-hole of the set of through-holes; and 
 a sensor module extending into a fourth through-hole of the set of through-holes. 
 
 
     
     
       10. The electronic device of  claim 9 , wherein:
 the second exterior surface region defines a plateau that is parallel to the first exterior surface region; 
 the glass member has a thickness from 1 mm to 3 mm as measured at the second exterior surface region; 
 the glass member has a thickness from 0.5 mm to 1 mm as measured at the first exterior surface region; and 
 the coating is viewable through the first and the second exterior surface regions. 
 
     
     
       11. The electronic device of  claim 10 , wherein a median load bearing capacity of the plateau is from 400 N to 600 N. 
     
     
       12. The electronic device of  claim 8 , wherein a difference between the first gloss value and the second gloss value is from 80 gloss units to 140 gloss units. 
     
     
       13. The electronic device of  claim 8 , wherein a peak sharpness of the second texture is from 0.75 microns −1  to 1.5 microns −1 . 
     
     
       14. The electronic device of  claim 8 , wherein a root mean square slope of the second texture is from 0.2 to 0.65. 
     
     
       15. An electronic device comprising:
 a display; 
 an enclosure at least partially surrounding the display and comprising:
 a front cover assembly including a front member positioned over the display; and 
 a rear cover assembly including a rear member comprising at least one of a glass or a glass ceramic, the rear member defining:
 a base region of an exterior surface of the rear member, the base region defining a first texture having:
 a first root mean square height from 1 micron to 5 microns; and 
 a root mean square slope from 0.1 to 0.75; and 
 
 a feature protruding with respect to the base region, the feature defining a plateau region of the exterior surface of the rear member, the plateau region having optical contrast with the base region and defining a second texture having a second root mean square height less than 0.25 microns; and 
 
 
 a camera assembly including a camera module positioned at least partially within a hole formed in the feature. 
 
     
     
       16. The electronic device of  claim 15 , wherein the base region is defined by a base portion of the rear member and the base portion has a clarity value ranging from about 1% to about 30%. 
     
     
       17. The electronic device of  claim 15 , wherein a gloss value of the base region is less than 10 gloss units as measured at an angle of 60 degrees. 
     
     
       18. The electronic device of  claim 15 , wherein a gloss value of the base region is from 10 gloss units to 20 gloss units as measured at an angle of 60 degrees. 
     
     
       19. The electronic device of  claim 15 , wherein a difference between a gloss value of the plateau region and a gloss value of the base region is from 70 gloss units to 160 gloss units as measured at an angle of 60 degrees. 
     
     
       20. The electronic device of  claim 15 , wherein the rear member is a lithium aluminosilicate glass ceramic member.

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. 63/073,521, filed Sep. 2, 2020 and titled “Electronic Devices with Textured Glass and Glass Ceramic Components,” the disclosure of which is hereby incorporated herein by reference its entirety. 
    
    
     FIELD 
     The described embodiments relate generally to textured glass and textured glass ceramic components. More particularly, the present embodiments relate to enclosures including the textured components and electronic devices including these enclosures. 
     BACKGROUND 
     Traditional glass covers for electronic devices may present a glossy outward facing surface. Some glass manufacturing processes, such as the down draw process and the fusion draw process, give a fine surface finish which produces a glossy appearance. The techniques and articles described herein are directed to textured glass and textured glass ceramic components which include both matte and glossy surface regions. 
     SUMMARY 
     Textured glass and textured glass ceramic components for electronic devices are disclosed herein. The textured component is typically included in the enclosure of the electronic device. A textured surface region of the component may be configured to provide a desired appearance and/or “feel” to the exterior surface of the enclosure. In some cases, the textured surface region provides a matte appearance to the exterior surface of the enclosure. 
     In some cases, the textured component is a cover member positioned over one or more components of the electronic device. As an example, the cover member may define a feature that protrudes beyond an adjacent region of the exterior surface to form a turret. One or more holes may extend through the protruding feature to facilitate positioning of a component of the electronic device. The textured component is typically chemically strengthened by ion exchange. 
     By the way of example, the electronic device may include a camera assembly positioned at least partially below the textured component. The textured component may define one or more holes extending though the thickness of the textured component. One or more camera modules of the camera assembly may extend into a corresponding hole of the one or more holes. The portion of the textured component including the holes may be thicker than an adjacent portion, so that the thicker portion of the component defines a protruding feature. 
     In some cases, the textured component includes differently textured regions along an external surface of the component. The differently textured surface regions may produce optical contrast between different portions of the component. For example, the differently textured surface regions may produce different gloss levels, different translucency values, or both. In some embodiments, each of the differently textured surface regions may have a sufficiently high light transmissivity that the color of an internal coating can be perceived through the component. 
     The differently textured surface regions may also provide a different “feel” to different portions of the component. In some embodiments, each of the textured surface regions may be configured so that the component has an acceptable strength level and/or ability to be cleaned of trapped debris. 
     In some cases, the enclosure includes a cover assembly and the textured component is part of the cover assembly. For example, the cover assembly may further include an interior coating and/or an exterior coating applied to the textured component. The interior coating may be a cosmetic coating, such as an ink layer. The exterior coating may include one or more of an anti-reflective coating, a smudge-proof coating, such as an oleophobic coating, and the like. 
     The disclosure provides an electronic device comprising a display, an enclosure at least partially surrounding the display, and a camera assembly. The enclosure comprises a front cover assembly including a front member positioned over the display and a rear cover assembly including a chemically strengthened rear member. The chemically strengthened rear member defines a base portion defining a base surface region and a feature protruding with respect to the base surface region. The feature defines a surface region having a texture comprising a mean pitch from 10 microns to 40 microns and a root mean square slope from 0.1 to 0.75. The camera assembly includes a camera module positioned at least partially in a hole formed through the feature. 
     In addition, the disclosure provides an electronic device comprising an enclosure including a cover assembly comprising a glass member. The glass member defines a first exterior surface region having a first gloss value greater than 90 gloss units as measured at 60 degrees and defining a first texture having a root mean square height less than 0.5 microns. The glass member further defines a second exterior surface region having a second gloss value less than 10 gloss units as measured at 60 degrees and defining a second texture having a root mean square height from 1 micron to 5 microns and a mean pitch from 10 microns to 40 microns. The cover assembly further comprises a coating disposed along an interior surface of the glass member and viewable through the first and the second textures. 
     The disclosure further provides an electronic device comprising a display, an enclosure at least partially surrounding the display, and a camera assembly. The enclosure comprises a front cover assembly including a front member positioned over the display and a rear cover assembly including a rear member comprising at least one of a glass or a glass ceramic. The rear member defines a base region of an exterior surface of the rear member, the base region defining a first texture having a root mean square height from 1 micron to 5 microns and a root mean square slope from 0.1 to 0.75. The rear member further defines a feature protruding with respect to the base region, the feature defining a plateau region of the exterior surface of the rear member, the plateau region having optical contrast with the base region and defining a second texture having a root mean square height less than 0.25 microns. The camera assembly includes a camera module positioned at least partially within a hole formed in the 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  shows a front view of an example electronic device including a textured cover member. 
         FIG.  1 B  shows a rear view of the electronic device of  FIG.  1 A . 
         FIG.  2    shows a rear view of another electronic device. 
         FIG.  3    shows a partial cross-section view of an electronic device. 
         FIG.  4    shows a partial cross-section view of an additional electronic device. 
         FIG.  5    shows a partial cross-section view of a textured cover member of an electronic device. 
         FIG.  6    shows an example of a detailed cross-section view of a first textured surface region of the cover member of  FIG.  5   . 
         FIG.  7    shows an example of a detailed cross-section view of a second textured surface region of the cover member of  FIG.  5   . 
         FIG.  8    shows a flow chart of an example process for forming a textured cover component. 
         FIG.  9    schematically shows a textured cover member after chemical strengthening. 
         FIG.  10    shows a block diagram of a sample electronic device that can incorporate a textured 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 electronic devices including a textured component. The textured component is typically included in the enclosure of the electronic device. A textured surface region of the component may be configured to provide a desired appearance and/or “feel” to the exterior surface of the enclosure. In some cases, the textured surface region provides a matte appearance to the exterior surface of the enclosure. In addition, the textured surface region may be configured so that the component has an acceptable strength level and/or ability to be cleaned of trapped debris. 
     In some cases, the textured component is included in a cover assembly positioned over one or more components of the electronic device. As examples, the textured component may be a cover member positioned over one or more elements of a camera assembly, over a display, over an antenna, over a charging assembly, and/or over any other device component. A cover member may also be referred to herein as a front member, a rear member, or in some cases simply as a member. The textured component may define one or more holes extending though the thickness of the textured component to facilitate positioning of the one or more components of the electronic device. For example, one or more optical modules of the camera assembly may extend into a corresponding hole of the textured component. The textured component is typically chemically strengthened by ion exchange. 
     Different surface regions of the textured component may be textured differently to produce optical and/or visual contrast. For example, each of the differently textured surface regions may reflect light differently. In addition, each of the differently textured surface regions may affect transmission of light through the component differently. In some cases, a surface region of a thicker portion of the textured component may be textured differently than a surface region of a thinner portion of the textured component, as described in more detail below. 
     In some cases, the differently textured surface regions have different gloss levels. For example, one textured surface region may have a matte appearance while another textured surface region may have a glossy appearance. A gloss measurement can be used to measure the light reflected from the component when a textured surface region is illuminated. In some embodiments, the visual contrast between differently textured surface regions can be characterized by the difference in gloss values. The description of gloss measurements and gloss values provided with respect to  FIG.  5    is generally applicable herein and, for brevity, is not repeated here. 
     In additional cases, differently textured portions of the component have different amounts of translucency. For example, one textured portion of the component may appear translucent while a differently textured portion of the component may appear transparent. A measurement of the percentage of light transmitted through a component can be used to determine an absolute measure of translucency. Relative measures of translucency, such as a contrast ratio, can also be determined. The additional description of absolute and relative measures of translucency provided with respect to  FIG.  5    is generally applicable herein and, for brevity, is not repeated here. 
     The differently textured surface regions may be configured to meet some common performance standards. For example, the differently textured portions of the component may each have a sufficiently high light transmissivity that the color of an internal coating can be perceived through the component. As an additional example, the differently textured surface regions may each be configured so that they do not provide an overly rough “feel” and so that they are not overly difficult to clean. 
     A textured surface region may be characterized by one or more texture parameters. For example, a textured surface region may be described by one or more of a root mean square (RMS) height of its surface features, a pitch of its surface features, and a root mean square (RMS) slope of its surface features. The description of these and other texture parameters provided with respect to  FIG.  6    is generally applicable herein and, for brevity, will not be repeated here. 
     In some cases, the textured component is a cover member that defines a feature that protrudes beyond an adjacent region of the exterior surface, also referred to herein as a protruding feature or simply as a feature. A surface region of the feature may define a plateau which is substantially parallel to the adjacent region of the exterior surface. One or more holes may extend through the protruding feature to facilitate positioning of one or more device components. A portion of the textured component including one or more through-holes may be thicker than an adjacent portion of the textured component, as described in more detail with respect to  FIGS.  1 B through  5   . The description provided with respect to  FIGS.  1 B through  5    is generally applicable herein and, for brevity, is not repeated here. 
     In some cases, a surface region of the thicker portion is textured to produce a lower gloss level than a surface region of the thinner portion of the cover member. As examples, a gloss measurement of the surface region of this thicker portion may give a gloss value less than about 20 gloss units, less than about 10 gloss units, from 1 gloss unit to less than 10 gloss units, from 2 gloss units from 7 gloss units, or from 10 gloss units to 20 gloss units, as measured at 60 degrees. In some cases, the surface region of this thicker portion may be characterized by one or more of the following roughness parameters. The root mean square height may be from 0.75 to 5 microns or from 1 micron to 5 microns. The mean pitch may be from 10 microns to 40 microns or from greater than 20 microns to less than or equal to 40 microns. The root mean square slope may be from 0.1 to 0.75, from 0.2 to 0.65, or from 0.3 to 0.75. The peak sharpness may be from 0.75 microns −1  to 1.5 microns −1 . 
     A gloss measurement of the surface region of this thinner portion may give a gloss value greater than about 70 gloss units, greater than about 80 gloss units, greater than about 90 gloss units, greater than about 100 gloss units, from 80 gloss units to less than 160 gloss units, from 90 gloss units to 150 gloss units, or from 100 gloss units to 140 gloss units, as measured at 60 degrees. The surface region of this thinner portion may have a root mean square height less than 0.5 microns, less than 250 nm, or from 1 nm to about 250 nm. 
     In additional cases, a surface region of the thicker portion is textured to produce a higher gloss level than a surface region of the thinner portion of the cover member. As an example, a gloss measurement of the surface region of this thicker portion may give a gloss value greater than about 70 gloss units, greater than about 80 gloss units, greater than about 90 gloss units, greater than about 100 gloss units, from 80 gloss units to less than 160 gloss units, from 90 gloss units to 150 gloss units, or from 100 gloss units to 140 gloss units, as measured at 60 degrees. The surface region of this thicker portion may have a root mean square height less than 0.5 microns, less than 250 nm, or from 1 nm to about 250 nm. A gloss measurement of the surface region of this thinner portion may give a gloss value less than about 20 gloss units, less than about 10 gloss units, from 1 gloss unit to less than 10 gloss units, from 2 gloss units to 7 gloss units, or from 10 gloss units to 20 gloss units as measured at 60 degrees. In some cases, the surface region of this thinner portion may be characterized by one or more of the following roughness parameters. The root mean square height may be from 0.75 microns to 5 microns or from 1 micron to 5 microns. The mean pitch may be from 10 microns to 40 microns, from 15 microns to 40 microns, or from greater than 20 microns to less than or equal to 40 microns. The root mean square slope may be from 0.1 to 0.75, from 0.2 to 0.65, or from 0.3 to 0.75. The peak sharpness may be from 0.75 microns −1  to 1.5 microns −1 . In some cases, the cover members of these two sets of cases may be configured so that the difference in the gloss value between the thicker portion and the thinner portion may be greater when the thicker portion has a lower gloss level than the thinner portion. 
     Some of the examples herein describe textured cover members and their properties. However, the discussion herein with respect to properties of textured cover members also relates more generally to textured components of electronic devices. These and other embodiments are discussed below with reference to  FIGS.  1 A- 10   . 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  shows a front view of an example of an electronic device  100  having an enclosure including a textured glass component. 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 notebook or laptop), 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 a desktop computer system, computer component, input device, appliance, or virtually any other type of electronic product or device component. 
     As shown in  FIG.  1 A , the electronic device  100  has an enclosure  110  including a cover assembly  122 . A cover assembly, such as cover assembly  122  or  124  (shown in  FIG.  1 B ), may simply be referred to herein as a cover. The cover assembly  122  further includes a cover member  132 . The cover member  132  may extend laterally across the cover assembly  122 , such as substantially across the width and the length of the cover assembly  122 . In additional cases, a cover assembly may include multiple cover members that together substantially extend laterally across the cover assembly. The cover assembly  122  may further include one or more coatings. For example, the cover assembly may include an oleophobic coating and/or an anti-reflective coating exterior. The cover assembly may also include an interior masking layer. 
     An exterior surface of the cover assembly  122  may at least partially define a front surface  102  of the electronic device. In the example of  FIG.  1 A , the cover assembly  122  defines a substantial entirety of the front surface  102  and may therefore be referred to as a front cover assembly. The cover assembly is positioned over a display  144  and the enclosure  110  may at least partially surround the display  144 . Typical cover assemblies described herein are thin, and typically include a cover member that is less than 5 mm in thickness, and more typically less than 3 mm in thickness, less than or equal to 2 mm in thickness, or less than or equal to 1 mm in thickness. 
     Although the cover assembly  122  is shown in  FIG.  1 A  as being substantially planar, the principles described herein also relate to cover assemblies and cover members which define a surface protrusion (such as shown in  FIG.  1 B ), a surface recess, and/or one or more curved surfaces. In some embodiments, a cover member may be three-dimensional or define a contoured profile. For example, a cover member may define a peripheral portion that is not coplanar with respect to a central portion. 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). 
     Portions of the cover member  132  positioned over a display  144  may be substantially transparent to visible light. Further, the cover member  132  may include one or more openings or through-holes. In the example of  FIG.  1 A , the cover member  132  includes an opening  123  which defines a speaker port. In some aspects, the cover member  132  can have a thickness from about 0.1 mm to 2 mm or from 0.2 mm to 1 mm. 
     In some cases, the cover member  132  may have a substantially uniform texture along its exterior surface. For example, the cover member  132  may have a smooth texture and may be substantially transparent to visible light. Typically portions of the cover member positioned over the display are substantially transparent to visible light. 
     In some cases, a cover member, such as the cover member  132  and/or the cover member  134 , may be a glass member, a glass ceramic member, or a member comprising one or more glass portions and one or more glass ceramic portions. In some cases, the cover member  132  may include multiple layers, each layer selected from a glass layer, a glass ceramic layer, and a polymer layer. The cover member may be a glass member when the primary structural members of the enclosure are all formed from glass. A cover member, such as the cover member  132  and/or the cover member  134 , is typically chemically strengthened by ion exchange. The discussion of chemical strengthening provided with respect to  FIGS.  8  and  9    is generally applicable herein and, for brevity, is not repeated here. 
     As shown in  FIG.  1 A , the enclosure  110  further includes a housing member  112 , which for simplicity may also be referred to herein as a housing. The cover assembly  122  may be coupled to the housing member  112 . For example, the cover assembly  122  may be coupled to the housing member with an adhesive, a fastener, an engagement feature, or a combination thereof. 
     The housing member  112  may at least partially define a side surface  106  of the electronic device  100  and may include one or more metal members. In the example of  FIG.  1 A , the housing member  112  defines all four sides or a continuous side surface  106  of the electronic device  100 . As shown in  FIG.  1 A , the housing member  112  is formed from a series of metal segments ( 114 ,  116 ) that are separated by dielectric segments  115  that provide electrical isolation between adjacent metal segments. For example, a dielectric segment  115  may be provided between a pair of 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 dielectric segments may be formed from one or more dielectric materials such as a polymer, a glass, or a ceramic material. In additional implementations the housing member may include one or more glass members, one or more glass ceramic members, or one or more ceramic members. The opening  117  may allow (audio) input or output from a device component such as a microphone or speaker or may contain an electrical port or connection. 
       FIG.  1 B  shows a rear view of the electronic device  100 . As shown in  FIG.  1 B , the enclosure  110  includes a cover assembly  124 . The cover assembly  124  further includes a cover member  134 . The cover member  134  may extend laterally across the cover assembly  124 , such as substantially across the width and the length of the cover assembly  124 . In additional cases, a cover assembly may include multiple cover members that together substantially extend laterally across the cover assembly. The cover assembly  124  may further include one or more coatings, such an oleophobic exterior coating and/or a cosmetic interior coating. 
     An exterior surface of the cover assembly  124  may at least partially define a rear surface  104  of the electronic device  100 . In the example of  FIG.  1 B , the exterior surface of the cover assembly  124  defines a substantial entirety of the rear surface  104  and may therefore be referred to as a rear cover assembly. The portion  128 , which extends from exterior to the interior surface of the cover assembly  124 , may define a region  148  of the exterior surface of the cover assembly  124 . The region  148  may also be referred to herein as a surface region, an exterior surface region or as a first or a base surface/exterior surface region. The portion  126 , which also extends from the exterior to the interior surface of the cover assembly  124 , may define a region  146  of the exterior surface of the cover assembly  124 . The region  146  may also be referred to herein as a surface region, an exterior surface region or as a second or raised surface/exterior surface region. 
     In some cases, a texture of the surface region  146  differs from a texture of the surface region  148 . The differently textured surface regions of the cover assembly  124  may produce optical contrast between different portions of the cover assembly  124 . In some cases, the differently textured surface regions may produce different gloss levels, different amounts of translucency, or both. For example, the portion  126  of the cover assembly  124  may have a lower gloss level and a higher amount of translucency (lower amount of light transmitted) than the portion  128  due at least in part to the differences in texture between the surface regions  146  and  148 . This example is not intended to be limiting and in other examples the portion  128  may have a lower gloss and/or a higher amount of translucency than the portion  126 . The description of textured surface regions provided with respect to  FIGS.  5  to  7    is generally applicable herein and, for brevity, is not repeated here. 
     The portion  126  of the cover assembly  124  may be thicker than the portion  128 . As shown in the example of  FIG.  1 B , the portion  126  defines a feature  127  which protrudes with respect to the surface region  148  and may also be referred to herein as a protruding feature. The feature  127  defines the surface region  146 . In the example of  FIG.  1 B , the surface region  146  defines a substantially plateau-shaped top of the feature  127 . The plateau defined by the surface region  146  may be substantially parallel to the surface region  148 . 
     The thickness of the portion  126  of the cover assembly  124  including the feature  127  may be greater than that of the portion  128  and may be at least 10%, 25%, or 50% and up to about 250% thicker than the thickness of the portion  128 . In some cases, the thickness of the thicker portion of the cover assembly (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  128  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. The amount of protrusion or offset between the surface region  146  and the surface region  148  may be from about 0.5 mm to about 1.5 mm or from about 0.75 mm to about 2 mm. The size of the feature  127  may depend at least in part on the size of a camera assembly or other device component underlying the protruding feature. In some embodiments, a lateral dimension (e.g., a width) of the protruding feature may be from about 5 mm to about 30 mm, from about 10 mm to about 20 mm, or from about 15 mm to 30 mm. 
     The cover assembly  124  may define one or more holes extending though its thickness to facilitate positioning of one or more device components. In some cases, the holes are defined by the thicker portion  126  of the cover assembly. In the view of  FIG.  1 B , the openings  155  and  159  of the holes are visible, while the openings to other holes are obscured by windows (e.g., window  187 ) and the retaining components  186  which hold the windows in place. For example, the retaining component  186  may be a ring, such as a metal ring, which contacts the surface region  146 . However, this example is not limiting and in some cases windows may be provided over a fewer number of device components or a greater number of device components than shown in the example of  FIG.  1 B . 
     The shape of the cover member  134  may have a shape similar to that of the cover assembly  124 . For example, the cover member  134  may also include a thicker portion defining a feature that protrudes with respect to a thinner portion, as shown in more detail in the cross-section view of  FIG.  5    (e.g., the feature  537  of  FIG.  5   ). 
     The electronic device  100  includes device components  175 ,  176 ,  177 ,  178 , and  179  extending at least partially into the feature  127 . As an example, the device components  176 ,  177 , and  178  are optical modules such as camera modules or a combination of camera modules and optical sensor modules, the device component  175  is an illumination module, and the device component  179  is a sensor module or a sensor array such as a microphone sensor module. 
     Typically, the electronic device  100  includes a camera assembly which in turn includes one or more optical modules. The example of  FIG.  1 B  shows optical modules  175 ,  176 ,  177 , and  178  of a camera assembly. More generally, the camera assembly may define any number of optical modules such as one, two, three, four, five, or six optical modules. Each of the optical modules  175 ,  176 ,  177 , and  178  may be substantially flush with, proud of, or recessed with respect to the raised region  146 . 
     The optical modules  175 ,  176 ,  177 , and  178  may include, but are not limited to, a camera module, an illumination module, a sensor, and combinations thereof. When the camera assembly includes multiple camera modules, each of the camera modules may have a different field of view or other optical property. In some cases, a camera module includes an optical sensor array and/or an optical component such as a lens, filter, or window. In additional cases, a camera module includes an optical sensor array, an optical component, and a camera module housing surrounding the optical sensor array and the optical components. The camera module may also include a focusing assembly. For example, a focusing assembly may include an actuator for moving a lens of the camera module. In some cases, the optical sensor array may be a complementary metal-oxide semiconductor (CMOS) array or the like. In some cases, a sensor array for a camera assembly may include a depth measuring sensor (e.g., a time of flight sensor), an ambient light sensor, an infrared sensor, an ultraviolet light sensor, a health monitoring sensor, a biometric sensor (e.g., a fingerprint sensor) or the like. 
     The example of  FIG.  1 B  also shows an additional electronic device component  179  positioned within or below the opening  159 . For example, the electronic device component  179  may be a microphone or another type of sensor. A variety of sensors may be positioned within and/or adjacent to the feature  127 . For example, a health monitoring sensor may be positioned at least partially within or adjacent to a protruding feature of a wearable device, such as a watch. As another example, a protruding feature may define a key region, a button region, or a trackpad region of a laptop or a phone. A biometric sensor, a touch sensor, a proximity sensor or the like may be positioned within or adjacent to the protruding feature. The description of sensors provided with respect to  FIG.  10    is generally applicable herein and, for brevity, is not repeated here. 
     In additional examples, the feature  127  need not include an opening for the additional electronic device component  179 . In this case, the sensor assembly for the additional electronic device component  179  may be positioned along an interior surface of the cover assembly below the feature  127 . 
     In addition to a display and a camera assembly, 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., 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.  10    and the description provided with respect to  FIG.  10    is generally applicable herein. 
       FIG.  2    shows a rear view of another electronic device  200 . As shown in  FIG.  2   , the enclosure  210  includes a cover assembly  224 , which defines a rear surface  204  of the electronic device  200 . The cover assembly  224  further includes a cover member  234 . The cover member  234  may be similar to the cover member  124  described with respect to  FIG.  1 B  and, for brevity, those details are not repeated here. 
     In the example of  FIG.  2   , the exterior surface of the cover assembly  224  defines a substantial entirety of the rear surface  204  and may therefore be referred to as a rear cover assembly. The portion  228  of the cover assembly  224  may define a surface region  248  and the portion  226  of the cover assembly  224  may define a surface region  246 . 
     In some cases, a texture of the surface region  246  differs from a texture of the surface region  248 . The differently textured surface regions of the cover assembly  224  may produce optical contrast between different portions of the cover assembly  224 . In some cases, the differently textured surface regions may produce different gloss levels, different amounts of translucency, or both. The description of texture surface regions provided with respect to  FIGS.  5  to  7    is generally applicable herein and, for brevity, is not repeated here. 
     The portion  226  of the cover assembly  224  may be thicker than the portion  228 . As shown in the example of  FIG.  2   , the portion  226  defines a feature  227  which protrudes with respect to the region  248 . The feature  227  defines the surface region  246 . In the example of  FIG.  2   , the surface region  246  defines a substantially plateau-shaped top of the feature  227 . 
     The cover assembly  224  may define one or more holes extending though its thickness to facilitate positioning of one or more device components. In some cases, the holes are defined by the thicker portion  226  of the cover assembly. In the example of  FIG.  2   , the holes define openings  256 ,  257 ,  258 , and  259  in the surface region  246 . 
     The example of  FIG.  2    shows optical modules  276 ,  277 , and  278  of a camera assembly. More generally the camera assembly may define any number of optical modules such as one, two, three, four, five, or six optical modules. As an example, each of the optical modules  276 ,  277 , and  278  is a camera module, an optical sensor module, or an illumination module and the device component  279  is a sensor such as a microphone. The description of device components such as optical modules and sensors provided with respect to  FIG.  1 B  is generally applicable here and, for brevity, is not repeated here. 
     An optical module, such as the optical modules  276 ,  277 , and  278  may be positioned at least partially within a hole in the cover assembly  224  (as shown in the partial cross-section view of  FIGS.  3  and  4   ). An optical module, such as the optical module  277 , may also be positioned within an opening to the hole as shown in the partial cross-section view of  FIG.  4   . Each of the optical modules  276 ,  277 , and  278  may be substantially flush with, proud of, or recessed with respect to the raised region  246 . In some cases, one or more of the optical modules  276 ,  277 , and  278  may include a window as part of its optical components, with the window being positioned within its housing. The windows may protect underlying components (e.g., cameras, lenses, other sensors), and may define part of the exterior surface of the cover assembly. In additional examples, a window may be provided over one or more of the optical components and sensors as previously illustrated with respect to  FIG.  1 B . The camera assembly may be coupled to an interior surface of the cover assembly as shown in  FIGS.  3  and  4   . 
     The housing member  212  may at least partially define a side surface  206  of the electronic device  200 . The housing member  212 , the metal segments  214  and  216 , the dielectric segments  215 , and the opening  217  may be similar to the housing member  112 , the metal segments  114  and  116 , the dielectric segments  115 , and the opening  117  and for brevity those details are not repeated here. 
       FIG.  3    shows a partial cross-section view of an electronic device  300  including an example rear cover assembly and a camera assembly. The electronic device  300  may be similar to the electronic device  100  of  FIGS.  1 A and  1 B  and the cross-section may be taken along A-A of  FIG.  1 B . The electronic device  300  includes a cover assembly  322  at the front and a cover assembly  324  at the rear of the electronic device  300 . 
     The cover assembly  322  includes cover member  332  and the cover assembly  324  includes a cover member  334 . Each of the cover member  332  and the cover member  334  may be a glass member, a glass ceramic member, or a member comprising one or more glass portions and one or more glass ceramic portions. Each of the cover member  332  and the cover member  334  may include an external coating, an internal coating, or a combination thereof.  FIG.  3    shows a coating  360  provided along an internal surface  352  of the cover member  334 . In some cases the coating  360  may provide the cover assembly  334  with a desired color. In additional cases, the coating  360  may function as a masking layer. 
     The exterior surface of the cover assembly  324  includes two different surface regions  346  and  348 . In the example of  FIG.  3   , the surface region  346  and the surface region  348  are textured differently. In particular, the surface region  346  has a rougher texture than the surface region  348  and may have a lower gloss value. However, this example is not limiting and in some cases the surface region defined by the thicker portion may have a smoother texture than the surface region defined by the thinner portion of the cover assembly, an example of which is shown in  FIG.  4   . The description of textured surface regions provided with respect to  FIGS.  5  to  7    is generally applicable herein and, for brevity, is not repeated here. 
     In the example of  FIG.  3   , the cover assembly  324  includes a thicker portion  326  and a thinner portion  328 . The thicker portion  326  defines the surface region  346  and the thinner portion  328  defines the surface region  348 . The thicker portion  326  also defines a feature  327  that protrudes with respect to the surface region  348 . A feature which protrudes with respect to another portion of the cover assembly may also be referred to generally herein as a protruding feature. Typically at least part of the surface region  348  and the portion  328  of the cover assembly  324  is substantially adjacent the protruding feature  327 . The portion  328  may also be referred to herein as a base portion and the surface region  348  as a base region. The surface region  346  of the exterior surface protrudes or is raised with respect to the region  348  and may therefore be referred to as a raised region, an offset region, an outer region, or simply as a top surface of the protruding feature  327 . As an example, the raised surface region  346  may substantially define a plateau. 
     As previously described with respect to  FIG.  1 B , the cover assembly  324  defines holes extending through the portion  326  and the protruding feature  327 . The cross-section view of  FIG.  3    shows holes  367  and  368 , which may also be referred to herein as through-holes. The openings to the holes are located in the surface region  346 , which may be a textured region. 
     The cover member  334  may also include a protruding feature as shown in more detail in the cross-section views of  FIG.  5    (e.g., the protruding feature  537  of  FIG.  5   ). As previously described for cover assembly  224 , the protruding feature of the member  334  may be part of a thicker portion of the member as compared to an adjacent portion of the member  334 . As shown in  FIG.  3   , the member  334  also at least partially defines the holes  367  and  368 . 
     The electronic device  300  further includes a camera assembly  370 . The partial cross-section view of  FIG.  3    shows two optical modules ( 377 ,  378 ) of the camera assembly  370 . As shown in  FIG.  3   , the camera assembly  370  is coupled to the coating  360 . In examples where the coating  360  does not extend under the protruding feature, the camera assembly  370  may be coupled more directly to the interior surface of the member  334 . In some cases, the camera assembly  370  may be coupled to the interior surface  342  of the cover assembly  324  with an adhesive bond, as may be provided by an adhesive layer. As an additional example, the camera assembly  370  may be coupled to the interior surface of the cover assembly  324  with a fastener or other form of mechanical attachment. 
     The camera assembly  370  further includes a support structure  371 . The support structure  371  may be configured to hold various elements of the camera assembly  370  in place. For example, each of the optical modules  377  and  378  may be mounted to the support structure  371 . In the example of  FIG.  3   , the support structure  371  includes a bracket  372  that has a non-planar profile. The shape of the bracket  372  is not limited to the example of  FIG.  3    and in other examples may have the form of a flat element. The bracket  372  may be coupled to an interior surface of the cover assembly  324 . In the example of  FIG.  3   , the support structure  371  also includes a frame  373  which nests at least partially within the bracket  372  and supports a circuit assembly  374 , which may be mounted on a printed circuit board. However this example is not limiting and in additional embodiments the frame  373  may be omitted. 
     The support structure  371  and the coupling between the camera assembly  370  and the interior surface of the cover assembly  324  may be configured to limit bending of the cover member  334  in the vicinity of the protruding feature  327 . For example, the support structure  371  may be configured to limit bending that would tend to increase outwards curvature of the surface region  346  (and increase its convexity). Limiting bending of the protruding region can limit bending-induced tensile stress along the surface region  346 . Further, the coupling between the camera assembly  370  and the interior surface of the cover assembly  324  may be sufficiently rigid so that the position of a neutral axis of the combination of the cover assembly  324  and the camera assembly  370  is shifted as compared to the corresponding neutral axis of the cover assembly  324  alone. For example, the neutral axis of the combination of the cover assembly  324  and the camera assembly  370  may be shifted inward, away from the exterior surface  344 , as compared to the corresponding neutral axis of the cover assembly  324  alone. In some cases, the shifting of the neutral axis may be most pronounced in the protruding feature  327  of the cover assembly  324 . 
     The first optical module  377  and the second optical module  378  are respectively aligned with the holes  367  and  368 . As shown in  FIG.  3   , the first optical module  377  extends substantially through the hole  367  and the second optical module  378  extends substantially through the hole  368 . In the example of  FIG.  3   , an end of each of the optical modules  377  and  378  extends beyond (protrudes beyond) the surface region  346 . In additional examples, an end of an optical module may be flush or recessed with respect to the surface region  346 , as shown in  FIG.  4   . In some cases, an electronic device may include at least one optical module that is flush with or extends beyond the surface region  346  and another optical module that is recessed with respect to the surface region  346 . 
     As previously described with respect to  FIGS.  1 B and  2   , an optical module may comprise a camera module, an illumination module, an optical sensor or the like. Typically the camera assembly  370  includes at least one camera module and may include two, three, four or five camera modules. The camera module is electrically connected to the circuit assembly  374 . As shown in  FIG.  3   , separate windows  387  and  388  are provided over the through-holes  367  and  368  and the retaining components  386  hold the windows  387  and  388  in place. For example, the retaining component  386  may be a ring, such as a metal ring, which surrounds the end of the optical module. Alternately, an optical module may include a window as part of its optical components, with the window being positioned within its housing. The windows may protect underlying components (e.g., cameras, lenses, other sensors), and may define part of the exterior surface of the cover assembly. 
     The cover assembly  324  further includes a coating  360  disposed along an interior surface  352  of the cover member  334 . In some cases, the coating may be a cosmetic or decorative coating. The coating  360  may define an interior surface of the cover assembly. When the cover assembly  324  includes a textured region, the appearance of the electronic device may be due to the combined effect of the textured region and the coating  360 . As shown in  FIG.  3   , the coating  360  is positioned underneath both the portions  326  and  328  of the cover assembly  324 . 
     In some cases, the coating  360  may provide one or more portions of the cover assembly  324  with a desired color. For example, the coating  360  may define a color visible along one or more surfaces of the cover assembly  324  or the cover member  334 . In additional cases, the coating  360  may function as a masking layer. In the example of  FIG.  3   , the portion  326  may have a color different from or similar to the portion  328 . In some cases, differently textured portions of the cover assembly  324  may have substantially different L* values. 
     In some cases, the coating  360  comprises a polymer. The coating  360  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  360  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  360  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. 
     In some cases, the coating may include a color layer (e.g., an ink, dye, paint, etc.) and/or a metal layer. As previously described, the coating  360  may include at least one color layer. The color layer may comprise a polymer and a colorant dispersed in the polymer and may be transparent, translucent, or opaque. More generally, any pigment, paint, ink, dye, sheet, film, or other layer may be used as the coating  360  or a portion thereof. In some embodiments, the coating  360  is a multilayer coating that includes a first color layer and a second color layer. Each of the color layers may be transparent, translucent, or opaque. Each of the color layers may include the same colorant or different color layers may include different colorants. The thickness of each of the color layers in the coating  360  may be from about 2 microns to about 10 microns. 
     The color layer(s) and the coating  360  may have a chromatic color or an achromatic color. The color of the coating  360  may be characterized using a color model. For example, in the hue-saturation-value (HSV) color model, the hue relates to the wavelength(s) of visible light observed when the color feature is viewed (e.g., blue or magenta) and the value relates to the lightness or darkness of a color. The saturation relates to the perceived colorfulness as judged in proportion to its brightness. As another example, coordinates in CIEL*a*b* (CIELAB) color space may be used to characterize the color, wherein L* represents brightness, a* the position between red/magenta and green, and b* the position between yellow and blue. 
     In some cases, the coating  360  may include multiple layers. As examples, the coating  360  may include one or more color layers, a metal layer, an optically clear layer, an optically dense layer, and combinations thereof. In additional cases, the coating need not include a color layer, but may include one or more of an optically dense layer and a metal layer. 
     For example, the coating  360  may include an optically dense layer. The optically dense layer may substantially reduce or prevent transmission of visible light, thereby “blocking” the view through the cover assembly  324  of components positioned behind the optically dense layer. In addition, the optical properties of the optically dense layer may be configured to adjust the lightness and/or the chroma of the coating  360 . 
     For example, the optical density of the optically dense layer 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. Generally, the optically dense layer comprises a polymer. The optically dense layer may further comprise one or more pigments, dyes, or a combination thereof. As an example, the optically dense layer has a substantially wavelength independent (neutral) reflectance and/or absorption spectrum over the visible range. In addition, the optically dense layer may have an achromatic characteristic color. The thickness of the optically dense layer may be from about 2 microns to about 10 microns. 
     In further embodiments, the coating  360  may comprise a metal layer in addition to one or more color layers. Such a metal layer may give a metallic effect to the coating as seen through the cover assembly  324 . When used to form a metallic marking, the metal layer may be a partial layer (e.g., having a smaller lateral dimension than a color layer). For example, the metal of the layer may be selected from aluminum, copper, nickel, silver, gold, platinum, and alloys thereof. In some cases, the metal layer may be configured to at least partially transmit visible light. For example, the metal layer may have a thickness greater than about 0.5 nm and less than 10 nm, less than 5 nm, less than 3 nm, less than 2 nm, or less than 1 nm. Thicker metal layers may be used for forming an indicium or another marking under the member. The marking may be in the form of an image, a pattern, text, a glyph, a symbol, indicia, a geometric shape, or a combination thereof. 
     The metal layer may be disposed along an interior surface  352  of the member  334 . In some cases the metal layer may be used in combination with an optically clear layer. The optically clear layer may have one or more mechanical properties (e.g., modulus, hardness and/or toughness) that limit or prevent propagation of cracks from the metal layer into the member  334 . The optically clear layer may be a polymeric layer and may have a thickness from about 1 micron to about 5 microns. The optically clear layer may be disposed along the interior surface  352  of the member  334 , the metal layer may be positioned between the optically clear layer and the optically dense layer, a first color layer may be positioned between the metal layer and the optically dense layer, and a second color layer may be positioned between the first color layer and the optically dense layer. 
     In addition, the coating may comprise additional polymeric layers behind and disposed along the optically dense layer. If components of the electronic device are glued to the coating, these additional layers may include a protective layer that protects the color layers of the multilayer coating from damage due to the glue. The additional layers may further include a layer inwards of the protective layer that facilitates adhesion of the coating to the glue. 
     The electronic device  300  further includes a display  384  and a touch sensor  382  provided below the front cover assembly  322 . The display  384  and the touch sensor  382  may be coupled to the front cover assembly  322 . The display  384  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. The touch sensor  382  may be configured to detect or measure a location of a touch along the exterior surface of the front cover assembly  322 . 
     Each of the cover assembly  322  and the cover assembly  324  is coupled to a housing component  314 , such as with an adhesive, a fastener, or a combination thereof. The housing component  314  may be similar to the housing component  114  of  FIG.  1 A . The housing component  314  at least partially defines an interior cavity  305  of the electronic device  300 . 
       FIG.  4    shows a partial cross-section view of an electronic device  400  including an example rear cover assembly and a camera assembly. The electronic device  400  may be similar to the electronic device  200  of  FIG.  2    and the cross-section may be taken along B-B. The electronic device  400  includes a cover assembly  422  at the front and a cover assembly  424  at the rear of the electronic device  400 . 
     The cover assembly  422  includes cover member  432  and the cover assembly  424  includes a cover member  434 . Each of the cover member  432  and the cover member  434  may be a glass member, a glass ceramic member, or a member comprising one or more glass portions and one or more glass ceramic portions. 
     Each of the cover members  432  and the cover member  434  may include an external coating, an internal coating, or a combination thereof.  FIG.  4    shows a coating  460  provided along an internal surface  452  of the cover member  434 . In some cases, the coating  460  may provide a desired color by defining a color visible along one or more surfaces of the cover member  434  and the cover assembly  424 . In additional cases, the coating  460  may function as a masking layer. 
     The exterior surface of the cover assembly  424  includes two different surface regions  446  and  448 . In the example of  FIG.  4   , the surface region  446  and the surface region  448  are textured differently. In particular, the surface region  446  has a smoother texture than the surface region  448  and may have a higher gloss value. However, this example is not limiting and in some cases the surface region defined by the thicker portion may have a rougher texture than the surface region defined by the thinner portion of the cover assembly, an example of which is shown in  FIG.  3   . The description of textured surface regions provided with respect to  FIGS.  5  to  7    is generally applicable herein and, for brevity, is not repeated here. 
     In the example of  FIG.  4   , the cover assembly  424  includes a thicker portion  426  and a thinner portion  428 . The thicker portion  426  defines the surface region  446  and the thinner portion  428  defines the surface region  448 . The thicker portion  426  also defines a feature  427  that protrudes with respect to the surface region  448 . Typically at least part of the surface region  448  and the portion  428  of the cover assembly  434  is substantially adjacent the protruding feature  427 . The portion  428  may also be referred to herein as a base portion and the surface region  448  as a base region. The surface region  446  of the exterior surface protrudes or is raised with respect to the region  448  and may therefore be referred to as a raised region, an offset region, an outer region, or simply as a top surface of the protruding feature  427 . As an example, the raised surface region  446  may substantially define a plateau. 
     As previously described with respect to  FIGS.  1 B,  2 , and  3   , the cover assembly  424  defines holes extending through the portion  426  and the protruding feature  427 . The cross-section view of  FIG.  4    shows holes  467  and  468 , which may also be referred to herein as through-holes. The cover assembly  424  further defines openings  457  and  458  to the holes  467  and  468 . The openings  457  and  458  are located in the region  446 . 
     The cover member  434  may also include a protruding feature as shown in more detail in the cross-section views of  FIG.  5    (e.g., the protruding feature  537  of  FIG.  5   ). Similarly to the cover assembly  224 , the protruding feature of the cover member  434  may be part of a thicker portion of the cover member as compared to an adjacent portion of the cover member  434 . As shown in  FIG.  4   , the member  434  also at least partially defines the holes  467  and  468 . 
     The electronic device  400  further includes a camera assembly  470 . The partial cross-section view of  FIG.  4    shows two optical modules ( 477 ,  478 ) of the camera assembly  470 . As shown in  FIG.  4   , the camera assembly  470  is coupled to the coating  460 . The description provided with respect to  FIG.  3    of coatings and of additional ways of coupling the camera assembly to the cover assembly is generally applicable herein and, for brevity, are not repeated here. 
     The optical module  477  and the optical module  478  are respectively aligned with the holes  467  and  468 . As shown in  FIG.  4   , the optical module  477  extends substantially through the hole  467  and the optical module  478  extends substantially through the hole  468 . In the example of  FIG.  4   , an end of each of the optical modules  477  and  478  are flush with the surface region  446 . In additional examples, an end of an optical module may protrude with respect to the surface region  446 , as shown in  FIG.  3    or may be recessed with respect to the surface region  446 . 
     As previously described with respect to  FIGS.  1 B,  2 , and  3   , an optical module may comprise a camera module, an illumination module, an optical sensor or the like. The optical module  477  and/or  478  may include a window as part of its optical components, with the window being positioned within its housing. The windows may protect underlying components (e.g., cameras, lenses, other sensors), and may define part of the exterior surface of the cover assembly. The description of device components such as optical modules and sensors provided with respect to  FIGS.  1 B and  2    is generally applicable here and, for brevity, is not repeated here. 
     The camera assembly  470  further includes a support structure  471 . The support structure  471 , the bracket  472 , the frame  473 , and the circuit assembly  474  may be similar to the support structure  371 , the bracket  372 , the frame  373 , and the circuit assembly  374  and, for brevity, those details are not repeated here. 
     The electronic device  400  further includes a display  484  and a touch sensor  482  provided below the front cover assembly  422 . The display  484  and the touch sensor  482  may be similar to the display  384  and the touch sensor  382  and, for brevity, those details are not repeated here. In addition, each of the cover assembly  422  and the cover assembly  424  is coupled to a housing component  414 , such as with an adhesive, a fastener, or a combination thereof. The housing component  414  may be similar to the housing component  114  of  FIG.  1 A . The housing component  414  at least partially defines an interior cavity  405  of the electronic device  400 . 
       FIG.  5    shows a partial cross-section view of an example cover member  534  of an electronic device. The cover member  534  includes differently textured surface regions  556  and  558 . The cover member  534  may be an example of the cover member  134  of  FIG.  1 B  or any other cover member described herein. 
     A portion  538  of the cover member  534 , which extends from exterior surface  554  to the interior surface  552 , may define a region  558  of the exterior surface  554 . The region  558  may also be referred to herein as the surface region  558 , as the exterior surface region  558  or as a first or a base surface region. A portion  536  of the cover member  534 , which also extends from the exterior surface  554  to the interior surface  552 , may define a region  556  of the exterior surface  554 . The region  556  may also be referred to herein as the surface region  556 , as the exterior surface region  556 , or as a second or a raised surface region. The surface region  559  may join the surface region  556  and the surface region  558 . 
     The portion  536  of the cover member  534  may be thicker than the portion  538 . As shown in the example of  FIG.  5   , the portion  536  defines a feature  537  which protrudes with respect to the surface region  558 . The feature  537  defines the surface region  556 . In the example of  FIG.  5   , the surface region  556  defines a substantially plateau-shaped top of the feature  537 . The surface region  559  may define a side surface of the protruding feature  537 . Through-holes  567  and  568  extend through the thicker portion  536  and the protruding feature  537 . 
     The combined thickness of the portion  536  of the cover member  534  including the feature  537  may be greater than that of the portion  538  and may be at least 10%, 25%, or 50% and up to about 250% thicker than the thickness of the portion  538 . In some cases, the thickness of the thicker portion of the cover member (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  538  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. The amount of protrusion or offset between the surface region  556  and the surface region  558  may be from about 0.5 mm to about 1.5 mm or from about 0.75 mm to about 2 mm. The size of the feature  537  may depend at least in part on the size of a camera assembly or other device component underlying the protruding feature. In some embodiments, a lateral dimension (e.g., a width) of the protruding feature may be 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.  5   , a texture of the surface region  556  differs from a texture of the surface region  558 . The differently textured surface regions of the cover member  534  may be configured to produce significant optical contrast between different portions of the cover member  534 . For example, the differently textured surface regions may produce differences in gloss, translucency, or both which are readily perceptible to the eye. In addition, the differently textured surface regions may be configured to produce perceptibly different “feels”. The differently textured surface regions may also be configured to meet some common performance standards. For example, the differently textured surface regions may each be configured so that they do not provide an overly rough “feel” and so that they are not overly difficult to clean. The differently textured surface regions may also be configured so that the corresponding portions of the cover member meet common performance standards. For example, the differently textured portions of the component may each have a sufficiently high light transmissivity that the color of an internal coating can be perceived through the component. In addition, the differently textured portions of the component may each have a minimum strength as measured, for example, using a ring on ring test. 
     In some cases, the differently textured surface regions may produce different gloss levels, different translucency values, or both. For example, the portion  536  of the cover member  534  may have a lower gloss and a higher translucency than the portion  538  due at least in part to the differences in texture between the surface regions  556  and  558 . This example is not intended to be limiting and in other examples the portion  538  may have a lower gloss and/or a higher translucency than the portion  536 . 
     In some cases, the texture of the surface region  556  has at least one roughness parameter, such as a root mean square surface height, a root mean square slope, a pitch, and/or a mean peak curvature, which is greater than that of the surface region  558 . In some cases, the surface region  558  may have a smooth texture that is tactilely and/or visually distinct from that of the surface region  556 . For example, the surface region  558  may have a relatively smooth texture resulting from a polishing process. In some cases, the surface region  556  may be configured to produce a gloss level that is lower than that of a window or lens of an optical module in the through-hole  567  or  568  (e.g., the window  187  of  FIG.  1 B ). The window or lens may have a highly polished surface, with a gloss level greater than about 40 gloss units or greater than about 50 gloss units. The additional description of roughness parameters provided with respect to  FIGS.  6  and  7    is generally applicable herein and, for brevity, is not repeated here. 
     In some cases, the textured surface region  556  may be characterized by one or more of the following roughness parameters. The root mean square height may be from 0.75 microns to 5 microns or from 1 micron to 5 microns. The mean pitch may be from 10 microns to 40 microns, from 15 microns to 40 microns, or from greater than 20 microns to less than or equal to 40 microns. The root mean square slope may be from 0.1 to 0.75, from 0.2 to 0.65, or from 0.3 to 0.75. The peak sharpness may be from 0.75 microns −1  to 1.5 microns −1 . The textured surface region  558  may have a root mean square height less than 0.5 microns, less than 250 nm, or from 1 nm to about 250 nm. 
     A textured surface region of the cover member, such as the textured surface region  556 , may be configured to provide a specified gloss level to the portion of the cover member defining the textured surface region. For simplicity, the gloss level measured by illuminating a textured surface region may be reference herein to the textured surface. However, when the portion of the cover member is translucent or transparent, some of the light illuminating the textured surface region will be transmitted through the cover member and may be reflected from an opposing surface of the cover member. The gloss value may depend in part on the index of refraction of the glass or glass ceramic portion of the cover. In some cases, the index of refraction may range from about 1.47 to about 1.57. In some cases, the endpoints of this range may vary by +/−10% or +/−5%. In some embodiments, measuring the gloss level by illuminating the textured region  556  may result in a gloss value of less than about 50 gloss units, less than about 40 gloss units, less than about 30 gloss units, less than about 20 gloss units, less than about 10 gloss units, from 1 gloss unit to less than 10 gloss units, from 2 gloss units to 7 gloss units, from 2 gloss units to 20 gloss units, from 10 gloss units from 20 gloss units, from 5 gloss units to 50 gloss units, from 10 gloss units to 50 gloss units, from 10 gloss units to 45 gloss units, or from 15 gloss units to 45 gloss units as measured at 60 degrees. The gloss level may be measured in the absence of a coating. 
     The gloss level of another surface region of the cover member, such as the textured region  558 , may be different from that of the textured region  556 . For example, the other surface region may have a higher gloss than the textured region  556 , such as when the other region has a smoother surface. For example, measuring the gloss level by illuminating the other surface region may result in a gloss value of greater than about 70 gloss units, greater than about 80 gloss units, greater than about 90 gloss units, greater than about 100 gloss units, from 80 gloss units to less than 160 gloss units, from 90 gloss units to 150 gloss units, or from 100 gloss units to 140 gloss units, as measured at 60 degrees. 
     The difference between the gloss level of the surface regions may be at least 10% and less than 100% or at least 10% and less than 50%. In some cases, the difference in the gloss value may be at least 10 gloss units, at least 20 gloss units, at least 50 gloss units, from 70 gloss units to 160 gloss units, from 80 gloss units to 140 gloss units, or from 90 gloss units to 150 gloss units as measured at 60 degrees. In some cases, the gloss of the textured region may be measured using commercially available equipment and according to ASTM or ISO standard test methods. The angle measurement may refer to the angle between the incident light and the perpendicular to the textured region of the surface. 
     A textured surface region of a cover member, such as the textured region  556 , may be configured to produce a translucent or hazy effect. A translucence level of the portion of the cover member defining the textured surface region can be assessed in several ways. For example, a translucence value can be measured by measuring the percentage of light incident on the textured surface region which is transmitted through the cover member. More specifically, the transmissive haze and/or the clarity can be measured to determine relative amounts of wide angle and narrow angle scattering. In addition, a relative translucence value can be determined as described below. A relative translucence value can be useful when a relatively small surface region is to be measured, such as a surface region in the range of 3 mm to 7 mm in diameter. 
     Relative translucence values include contrast ratio and translucency parameters. The contrast value is determined by measuring the reflected light using a white background and the reflected light using a black background. For example, the contrast ratio may be calculated as the luminance flux of a material on a black background divided by the luminance flux of a material on a white background. This contrast value is 1 for opaque materials and 0 for transparent materials and is more sensitive for materials having about 50% or greater light transmission. The translucency parameter is determined by measuring coordinates in CIEL*a*b* (CIELAB) color space when the material is on a black background and on a white background. For example, the translucency parameter may be calculated as the square root of ((L white −L black ) 2 +(a white −a black ) 2 +(b white −b black ) 2 ). In some cases, a higher translucency value indicates that a lesser amount of light is being transmitted through the material. 
     A textured surface region of the cover member may be configured to provide a specified level of cleanability. For example, the texture of the surface region may be configured so that a root mean square (RMS) height of the features is not overly large. The texture may also be configured so that a size of any recessed surface features and a spacing between surface features is sufficiently large to facilitate cleaning. In addition, the texture may be configured so that the root mean square (RMS) slope and/or the mean peak curvature of the surface features is small enough to provide the desired tactile properties in addition to the desired level of cleanability. 
     The strength or load bearing capacity of the cover member  534  may be tested by applying a load to the protruding feature. For example, a load may be applied to the rear surface of the protruding feature to introduce a tensile stress at the front (top) surface of the protruding feature. In some cases, the median load bearing capacity of the top of the protruding feature is from 400 N to 600 N or from 450 N to 550 N. In additional cases, 90% or more of the load bearing capacity values range between 300 N and 700 N. In some cases the strength is measured prior to chemical strengthening while in other cases the strength may be measured following chemical strengthening. 
     The cover member  534  may be a glass member, a glass ceramic member, or a member comprising one or more glass portions and one or more glass ceramic portions. A glass member or glass portion of a member typically includes a silica-based glass material. The glass material may have a network structure, such as a silicate-based network structure. 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+ . As previously discussed with respect to  FIG.  1 B , the cover member  534  may be chemically strengthened through ion exchange. For example, the ions within the glass or glass ceramic may be exchanged for larger ions to create a compressive stress region along one or more surfaces of the cover member. The description of chemical strengthening provided with respect to  FIGS.  8  and  9    is generally applicable herein and, for brevity, is not repeated here. 
     A glass ceramic member or a glass ceramic portion of a member includes a glass ceramic material. As referred to herein, a glass ceramic material comprises one or more crystalline phases formed by crystallization of a (precursor) glass material. Therefore, the glass ceramic material is at least partially crystallized. For example, a glass ceramic material may include from 50% to 90%, from 60% to 90%, from 70% to 90%, from 75% to 95%, or greater than 80% of a crystalline phase by volume. The glass ceramic material may further comprise an amorphous (glass) phase. The glass ceramic material 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 a glass ceramic material from another glass ceramic composition system. In some embodiments, the glass ceramic portion comprises an aluminosilicate glass ceramic or a boroaluminosilicate glass ceramic. In some embodiments, the glass ceramic material is formed by crystallization of an aluminosilicate glass material. For example, a lithium aluminosilicate glass ceramic member can be formed by crystallization of a lithium aluminosilicate (LAS) glass material. 
       FIG.  6    shows a detail view of a surface region  656  of a cover member  634 . The surface region  656  may be an example of the surface region  556  of  FIG.  5    in detail area  1 - 1  or similarly textured surface regions as described herein. The cover member  634  may be an example of the cover member  534  or of any of a variety of cover members described herein. Details of these cover members are applicable to the cover member  634  and, for brevity, will not be repeated here. The surface region  656  may also be similar to the surface region of the cover member  334  which corresponds to the surface region  346  of the cover assembly  324  and the surface region of the cover member  424  which corresponds to the surface region  448  of the cover assembly  424 . 
     The surface region  656  comprises a plurality of surface features  680 . As shown schematically in  FIG.  6   , the surface features  680  may define one or more recesses, such as the surface feature  684 . The surface features  680  may also define one or more protrusions, such as the surface feature  682 . In some embodiments, an average magnitude of the radius of curvature of the recesses is greater than an average magnitude of the radius of curvature of the protrusions. The shapes of the protrusions and recesses schematically shown in  FIG.  6    are exemplary and not intended to be limiting. 
     In some embodiments, the surface features  680  define a set of hills and valleys. The hills and valleys may be defined using areal texture analysis techniques as described below. The surface feature  682  may generally correspond to a hill feature and the surface feature  684  may generally correspond to a valley feature. As shown in  FIG.  6   , the set of hills and valleys may have a non-uniform or an irregular spacing between hill features and/or valley features. In additional embodiments, a set of hills and valleys has a substantially uniform spacing between hill features, valley features, or a combination thereof. 
     The heights of the surface features  680  may be measured with respect to a reference surface  681 . For example, the heights of the hills may be determined from the maximum points (e.g., point  683 ) and the heights of the valleys may be determined from the minimum points (e.g., point  685 ). 
     The example of the surface features provided in  FIG.  6    is not limiting and in general the surface features  680  of a surface region of the cover member  634  may define any of a range of shapes or configurations. The surface features  680  may have a variety of shapes, such as rounded or angular features. As examples, the surface features  680  may define a circular, oval, polygonal, rectangular, or irregular surface contour. Furthermore, the surface features  680  may define protrusions, recesses, or a combination thereof and may have any suitable shape and may be pyramidal, conical, or cylindrical. 
     The surface features  680  may be configured to provide particular optical properties to the surface region  656 , as well as to a cover assembly and an electronic device including the cover member  634 . However, the surface features  680  defining the texture of the surface region may not be individually visually perceptible. In some cases, the texture of the surface region may cause the cover member  634  to appear translucent, rather than transparent. In some cases, the texture may be configured to provide particular levels of such optical properties as gloss, translucence, color, and combinations thereof. The following discussion of optical properties and texture parameters is generally applicable to the textured surface regions described herein, including the surface regions  556 ,  558 ,  656 , and  758 . 
     A textured surface region of the cover member may be configured to provide a specified level of transmissive haze to the corresponding portion of the cover member. In some cases, the transmissive haze of the surface region may be measured using commercially available equipment and according to ASTM or ISO standard test methods. The transmissive haze may relate to the amount of light subject to wide angle scattering (e.g., greater than 2.5 degrees). 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 scattering may be measured for the cover assembly or cover member as removed from the electronic device. In some cases, 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%. For example, the transmissive haze may be from about 60% to about 90% or from about 70% to about 80%. In other cases, the transmissive haze of the surface region may have a lower amount of transmissive haze such as less than 50%, less than 40%, less than 30%, or less than 25%. 
     A textured surface region of the cover member may be configured to provide a specified level of clarity to the corresponding portion of the cover member. The clarity or the transmissive narrow angle scattering of the textured region may be measured using commercially available equipment and according to ASTM or ISO standard test methods. The transmissive narrow angle scattering may be measured using a haze-gard i device available from BYK or a GC 5000L variable photometer available from Nippon Denshoku. A clarity value may be determined from measurements of the intensity in a central region (I central ) and an intensity in a ring around the central region (I ring ). For example, the clarity value may be equal to 100%*(I central −I ring )/(I central +I ring ). The clarity or the transmissive narrow angle scattering may be measured for the cover assembly or cover member as removed from the electronic device. In some cases, the clarity may be less than about 50%, less than about 40%, less than about 30%, less than about 20%, less than about 15%, or less than about 10%. For example, the clarity may be from about 5% to about 30%, from about 5% to about 20%, from about 5% to about 15%, or from about 5% to about 15%. 
     In some cases, a textured surface region of the cover member may be configured to provide a specified level of visual uniformity to the corresponding portion of the cover member. The graininess of a textured region may be measured under diffused illumination using commercially available equipment. The graininess may be measured similarly for a textured region of a cover assembly. In some cases, an image of the textured surface region of the cover member may be obtained using a digital camera and the lightness of each pixel of the image may be determined, thereby allowing determination of the lightness variation across the textured surface. For example, the BYK-mac device available from BYK may produce a graininess value determined from a histogram of the lightness levels. In some cases, the graininess of the textured surface region may be less than about 1.5 or less than about 1.0. In addition, the graininess may be from about 0.1 to about 1.5, from about 0.1 to about 1.0, from about 0.25 to about 1.5, from about 0.25 to about 1.0, from about 0.5 to about 1.5, or from about 0.5 to about 1.0. These graininess values may be measured prior to application of any coating to the cover member. 
     Surface texture parameters include areal surface texture parameters such as amplitude parameters, spatial parameters, and hybrid parameters. Surface filtering may be used to exclude surface noise and/or surface waviness before determining the surface texture parameters. In addition, a segmentation technique may be used to determine feature parameters such as the maximum diameter, the minimum diameter, the area, and the perimeter. These parameters may be calculated on the basis of the feature shape as projected onto the reference surface (e.g., a reference plane). Mean values may be determined for a given class of surface features (e.g., hills or valleys). Surface texture parameters and methods for determining these parameters (including filtering and segmentation) are described in more detail in International Organization for Standardization (ISO) standard 25178 (Geometric Product Specifications (GPS)—Surface texture: Areal). These surface texture parameters may be measured using commercially available equipment, such as a Keyence roughness measurement microscope (e.g., a laser scanning confocal microscope) or a Zygo surface measuring device (e.g., a laser interferometer). 
     For example, the surface features (e.g.,  680 ) of one or more surface regions of the cover member  634  may be characterized, in part, by the heights of the surface features. The height may be measured with respect to a reference surface, such as the arithmetical mean of the surface (schematically shown by line  681  in  FIG.  6   ). The heights of the surface features may not be uniform, so that the surface features have a distribution of heights. In some cases, the magnitude of the heights of the surface features of one surface region may fall in the range from zero to about 5 microns, from zero to about 2.5 microns, from zero to about 2 microns, from zero to about 1.5 microns, or from zero to about 1 micron. The surface features may be characterized by the root mean square height Sq or the arithmetic mean height Sa of the surface. The root mean square (RMS) height of the surface features may be from about 0.75 microns to about 5 microns, from about 1 micron to about 5 microns, from greater than zero and less than about 2.5 microns, greater than zero and less than about 2 microns, greater than zero and less than about 1.5 microns, greater than zero and less than about 1 micron, from about 0.1 microns to about 2.5 microns, from about 0.1 microns to about 2 microns, from about 0.1 microns to about 1.5 microns, from about 0.1 microns to about 1.25 microns, from about 0.1 microns to about 1.0 micron, from about 0.2 microns to about 2.5 microns, from about 0.2 microns to about 2 microns, from about 0.2 microns to about 1.5 microns, from about 0.2 microns to about 1.25 microns, from about 0.2 microns to about 1.0 micron, from about 0.25 microns to about 2.5 microns, from about 0.25 microns to about 2 microns, from about 0.25 microns to about 1.5 microns, from about 0.25 microns to about 1.25 microns, from about 0.25 microns to about 1.0 micron, from about 0.5 microns to about 2.5 microns, from about 0.5 microns to about 2 microns, from about 0.5 microns to about 1.5 microns, from about 0.5 microns to about 1.25 microns, or from about 0.5 microns to about 1.0 micron. In some cases, one textured region may be referred to as being rougher than another textured region when it has a greater RMS height. 
     The RMS height of another region of the exterior surface of the cover member, such as the base region, may be similar to or different from that of a textured region such as  556  or  656 . For example, the RMS height of the raised region may be greater than that of the base region. For example, the RMS height of the raised region may be at least 10% and less than 150%, at least 10% and less than 100%, or at least 10% and less than 50% greater than that of the base region. In some cases, the RMS height of the base region may be less than 0.5 microns, less than 250 nm, or from 1 nm to about 250 nm. In additional cases, the RMS height of the base region may be similar to that of a highly polished surface, such as from about 1 nm to about 150 nm, from about 1 nm to about 125 nm, from about 1 nm to about 100 nm, from about 1 nm to about 75 nm, from about 1 nm to about 50 nm, from about 1 nm to about 25 nm, or from 1 nm to about 10 nm. 
     In addition, the surface features of one or more surface regions may be characterized by lateral parameters, such as the distance between peaks. The spacing between peaks may not be uniform, so that there is a distribution of spacings between peaks. The average (mean) distance or spacing between peaks may be referred to as the average pitch or mean pitch. The average pitch may be from about 1 micron to about 20 microns, from about 1 micron to about 15 microns, from about 1 micron to about 10 microns, from about 2.5 microns to about 20 microns, from about 2.5 microns to about 15 microns, from about 2.5 microns to about 10 microns, from about 5 microns to about 40 microns, from about 5 microns to about 20 microns, from about 5 microns to about 15 microns, from about 10 microns to about 40 microns, from about 15 microns to about 40 microns, greater than 20 microns to 40 microns, or from about 5 microns to about 10 microns. 
     In some embodiments, the surface features of one or more surface regions may be configured so to have a particular ratio of the average height of the peaks to the average spacing of the peaks. For example, the ratio of the RMS height to the mean pitch may be from about 0.01 to about 0.6, from about 0.01 to about 0.3, from about 0.02 to about 0.6, from about 0.02 to about 0.3, from about 0.03 to about 0.6, from about 0.03 to about 0.3, from about 0.04 to about 0.6, or from about 0.04 to about 0.3. 
     The surface features of one or more surface regions may also be characterized by a lateral size. For example, the surface features may be characterized by a maximum lateral (or linear) size and a minimum lateral (or linear size). The surface features may have a maximum lateral size small enough that they are not visually perceptible as individual features. In addition, the lateral size and spacing of the surface features may be configured so that the cover member has a sufficiently low level of graininess. 
     The surface features of one or more surface regions may be characterized by the root mean square slope (Sdq), also referred to as the root mean square gradient. In some embodiments, the root mean square slope may be greater than zero and less than about 1.25, greater than zero and less than about 1, from 0.1 to less than about 1.25, from about 0.1 to less than about 1, from about 0.1 to about 0.75, from about 0.1 to about 0.5, from about 0.2 to about 0.65, from about 0.25 to less than about 1, from about 0.25 to about 0.75, or from about 0.1 to about 0.5, or from about 0.3 to about 0.75. In some cases, the root mean square slope of the raised region is greater than that of the base region. For example, the root mean square slope of the raised region may be at least 10% and less than 60% greater than that of the base region. 
     The surface features of one or more surface regions may also be characterized by the curvature of the peaks (also referred to as summits), such as by the arithmetic mean summit curvature S sc , also referred to herein as the mean peak curvature. In some embodiments, the arithmetic mean summit curvature is greater than zero and less than about 2.0 microns, greater than zero and less than or equal to about 1.5 microns −1 , from about 0.1 microns −1  to about 2.0 microns −1 , from about 0.1 microns −1  to about 1.5 microns −1 , from about 0.25 microns −1  to about 2.0 microns −1 , from about 0.25 microns −1  to about 1.5 microns −1 , from about 0.5 microns −1  to about 2.0 microns −1 , from about 0.5 microns −1  to about 1.5 microns −1 , from about 0.75 microns −1  to about 2.0 microns −1 , from about 0.75 microns −1  to about 1.5 microns −1 , or from about 0.9 microns −1  to about 1.35 microns −1 . In some cases, the mean peak curvature of the raised region is greater than that of the base region. For example, the mean peak curvature of the raised region may be at least 10% and less than 50% greater than that of the base region. 
     The surface features of one or more surface regions may also be characterized by an autocorrelation length. In some embodiments, the autocorrelation length is from about 1 micron to about 50 microns, from about 2 microns to about 30 microns, or from about 3 microns to about 25 microns. 
     As previously described with respect to  FIG.  3   , a coating may be disposed along an interior surface of the cover member. In some cases, the surface features of the cover member may be configured to minimize less desirable visual effects when the coating is viewed through a textured region, such as the textured region  656  or  758 . For example, it may be preferred that the texture does not produce an undesirable amount of visual contrast variation and/or a visual texture. 
       FIG.  7    shows a detail view of a surface region  758  of a cover member  734 . The surface region may be an example of the surface region  558  of  FIG.  5    in detail area  2 - 2  or similarly textured surface regions as described herein. The cover member  734  may be an example of the cover member  534  or of any of a variety of cover members described herein. Details of these cover members are applicable to the cover member  734  and, for brevity, will not be repeated here. The surface region  758  may also be similar to the surface region of the cover member  334  which corresponds to the surface region  348  of the cover assembly  324  and the surface region of the cover member  434  which corresponds to the surface region  446  of the cover assembly  424 . 
     The surface region  758  comprises a plurality of surface features  780 . As shown in  FIG.  7   , the surface features  780  may define one or more recesses, such as the surface feature  784 . The surface features  780  may also define one or more protrusions, such as the surface feature  782 . The heights of the surface features  780  with respect to the reference surface  781  are generally smaller than those of the surface features  680  with respect to the reference surface  681 , although the scale of  FIG.  7    may be somewhat exaggerated in order to better illustrate details of the textured surface region. In some cases, the surface region  758  may be obtained by polishing a textured surface region similar to the surface region  656  of  FIG.  6   . 
     In some cases, the root mean square height of the surface region  758  may be less than 0.5 microns, less than 250 nm, from 1 nm to about 250 nm, from about 1 nm to about 125 nm, from about 1 nm to about 100 nm, from about 1 nm to about 75 nm, from about 1 nm to about 50 nm, from about 1 nm to about 25 nm, or from about 1 nm to about 10 nm. 
       FIG.  8    shows a flow chart of an example process  800  for forming a textured cover component, such as a glass cover member, a glass ceramic cover member, or a cover member comprising one or more glass portions and one or more glass ceramic portions. The description of suitable glass materials and glass ceramic materials provided with respect to  FIG.  6    is generally applicable to the components and cover members described herein and, for brevity, is not repeated here. 
     The process  800  includes an operation  802  of mechanically texturing the component, an operation  804  of chemically etching the component, an operation  806  of selectively polishing the component, and an operation  808  of chemically strengthening the component. In some cases, the component includes a thicker portion and a thinner portion. The thicker portion may define a protruding feature and a raised surface region and the thinner portion may define a base surface region as shown, for example, in  FIG.  5   . 
     As shown in  FIG.  8   , the process  800  includes an operation  802  of mechanically texturing the component to form a textured surface region. Typically the operation  802  involves removing material from the external surface of the component using particles of an abrasive material, such cubic boron nitride, diamond, or silicon carbide. When the operation  802  involves multiple mechanical treatment steps, the earlier steps typically use a coarser abrasive than the later steps. The operation  802  may include a grinding operation, such as a CNC grinding step using a fixed abrasive material (e.g., metal or resin bonded to the grinding tool). The textured surface region is formed along the external surface of the component. The textured surface region may be formed on a raised surface region defined by a protruding feature of the component, on a base surface region, or both. In additional examples the raised surface region and the base surface region may be differently textured during the operation  802 . For example, the raised surface region may be given a rougher or a smoother texture than the base surface region. By the way of example, a textured surface region of the component may have a root mean square height of from about 0.5 microns to about 2 microns, a pitch from about 2.5 microns to about 20 microns, and a root mean square slope from about 0.5 to about 1.75 following operation  802 . Optionally, the component may be washed following the operation  802 . 
     The process  800  further includes an operation  804  of chemically etching the textured surface region of the component produced by the operation  802 . The operation  804  may also be referred to herein as an etching operation. Chemical etching techniques for glass and glass ceramic components may involve using a suitable acid or base (e.g., a hydrofluoric acid-based etchant) to remove portions of the component. The chemical etching may occur in the liquid phase or in a gas phase. Etching techniques also include reactive ion etching, which may use a mixture of a fluorine containing compound such as CH 4 , CHF 3 , SF 6  and the like in a gas such as argon or xenon. The etch treatment may etch the component to a sufficient depth to remove at least some of the small fissures or other such features formed during the operation  802  of mechanically texturing the component. In addition, the etch treatment may remove or reduce small fissures or other such features resulting from prior machining operations, such as machining operations to form the protruding feature and through-holes in the component. In some cases, the etching time is longer for a glass ceramic component than for a glass component of similar overall composition. In some cases, the pitch may generally increase and the root mean square slope may generally decrease after the operation  804 . In additional cases, the root mean square height may also increase after the operation  804 . By the way of example, the textured surface region of the component may have a root mean square height of from about 0.75 microns to 5 microns, a pitch from about 10 microns to 40 microns, and a root mean square slope from 0.1 to 0.75 following operation  804 . Optionally, the component may be washed following the etch treatment  804 . 
     The process  800  further includes an operation  806  of selectively polishing the textured region produced by the operation  804 . For example, the operation  808  may be a mechanical polishing operation. The polishing operation may use a loose abrasive material, which may be supplied in a slurry to a polishing pad. In some cases, a polishing operation may have a polishing depth (the depth of the glass material removed) which is less than the full height of the surface features resulting from the operation  804 . In some cases, the operation  806  may polish an external surface of the base portion and a side portion of the protruding feature, but not the top surface of the protruding feature. Alternately, the operation  806  may polish the top surface of the protruding feature, but not the base region of the component. For example, a surface of the component, such as the top surface of the protruding feature, may be masked to prevent polishing of the texture on this surface. The polished surface region may have a root mean square height less than 0.5 microns or less than 0.25 microns. Optionally, the component may be washed following the operation  808 . 
     The process  800  further includes an operation  808  of chemically strengthening the component. In some cases, the operation  808  may take place after the operation  806  has been completed. The operation  808  may include an ion exchange operation which chemically strengthens the component. During the ion exchange operation, ions present in the glass or glass ceramic material can be exchanged for larger ions in a region extending from a surface of the component. The ion exchange may form a compressive stress layer (or region) extending from a surface of the component, as schematically illustrated in  FIG.  9   . In some cases, the operation  808  includes multiple ion exchange operations, which may occur sequentially or simultaneously. In some embodiments, a compressive stress layer is formed at each of the textured exterior surface and the interior surface of the component. A tensile stress layer may be formed between these compressive stress layers. 
     For example, an ion-exchangeable material of the component may include monovalent or divalent ions such as alkali metal ions (e.g., Li + , Na + , or K + ) or alkaline earth ions (e.g., Ca 2+  or Mg 2+ ) which may be exchanged for other alkali metal or alkaline earth ions. If the component comprises sodium ions, the sodium ions may be exchanged for potassium ions. Similarly, if the component comprises lithium ions, the lithium ions may be exchanged for sodium ions and/or potassium ions. In some embodiments, the compressive stress layer extends to a depth (or thickness) in the component which is greater than a lowest depth of the surface texture. 
     In an example, the chemical strengthening process involves exposing the component to a medium containing the larger ion, such as by immersing the component in a bath containing the larger ion or by spraying or coating the cover member with a source of the ions. For example, a salt bath comprising the ion of interest (e.g., a potassium nitrate bath) may be used for ion exchange. Suitable temperatures for ion exchange are above room temperature and are selected depending on process requirements. The ion exchange process may be conducted at a temperature below the strain point of the glass. The component may be cooled following the ion exchange operation. Depending on the factors already discussed above, a compression layer as deep as about 10-250 microns can be formed in a glass component. The surface compressive stress (CS) may be from about 300 MPa to about 1100 MPa. A mask can be used to shield portions of the component from ion exchange as desired. Optionally, the component is washed after the ion exchange operation  808 . In some cases, the component is selectively polished again after the ion exchange operation  808 . 
     In some embodiments, the process  800  may include additional operations. For example, the process  800  may include an operation of machining a workpiece or blank to a desired shape prior to operation  802 . The operation of machining the workpiece or blank may include removing material around the portion of the workpiece that is to become the protruding feature. The operation of machining the workpiece or blank may further include drilling one or more holes in the component, such as a through-hole extending through a portion of the component. The operation of machining a workpiece or blank may involve one or more of a computer numerical control (CNC) machining process such as a CNC milling process, a CNC grinding process, and/or a CNC drilling process. The process  800  may alternately or additionally include one or more of a washing operation, a polishing operation, and/or a coating operation. 
       FIG.  9    schematically shows a cover member  934  after a chemical strengthening operation. The cover member  934  includes a protruding portion  937 , a surface region  956  defining a top of the protruding portion, a base portion  938 , and a surface region  958 . Through-holes  967  and  968  extend through the cover member  934  and its protruding portion  937 . 
     As shown in  FIG.  9   , a compressive stress layer  994  extends from the exterior surface  954  and a compressive stress layer  992  extends from the interior surface  952  of the cover member  934  (not shown to scale). The compressive stress layer  994  may therefore be referred to as an exterior compressive stress layer and the compressive stress layer  992  may therefore be referred to as an interior compressive stress layer. A tensile stress layer  993  is positioned between the compressive stress layers  992  and  994 . In the example of  FIG.  9   , the compressive stress layer  994  has substantially the same depth as the compressive stress layer  992 . However, this example is not limiting and in some cases the depth of the compressive stress layer  994  may be different from that of the compressive stress layer  992 . For example, the depth of the compressive stress layer  994  may be substantially greater than that of the compressive stress layer  992 . 
     As shown in  FIG.  9   , the cover member  934  also includes a compressive stress layer  996  extending from a wall surface defining a through-hole, such as the wall surface  955  defining the through-hole  967 . For example, the compressive stress layer  996  may be created when the through-hole  967  is formed prior to a chemical strengthening operation. The compressive stress layer  996  may have a depth substantially the same as that of the compressive stress layer  992  or  994 , or may have some other depth. The cover member  934  may be an embodiment of the cover member  534  of  FIG.  5    or any other cover member described herein. 
     As examples, the depth of the compressive stress layer  994  for a glass cover member may be from 75 microns to 250 microns, from 100 microns to 250 microns, or from 125 microns to 250 microns. In some cases, a compressive stress layer (e.g.,  992 ,  796 , or  798 ) may have a depth greater than the depth of any subsurface features remaining from the texturing process. The depth of the compressive stress layer  992  may be the same as that of the compressive stress layer  994  or may be from about 5 microns to about 100 microns or from about 5 microns to about 50 microns. 
       FIG.  10    shows a block diagram of a sample electronic device that can incorporate a textured component as described herein, such as a textured cover member. The schematic representation depicted in  FIG.  10    may correspond to components of the devices depicted in  FIGS.  1 A to  9    as described above. However,  FIG.  10    may also more generally represent other types of electronic devices with cover assemblies as described herein. 
     In embodiments, an electronic device  1000  may include sensors  1020  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  1008  may be turned off, disabled, or put in a low energy state when all or part of the viewable area of the display  1008  is blocked or substantially obscured. As another example, the display  1008  may be adapted to rotate the display of graphical output based on changes in orientation of the device  1000  (e.g., 90 degrees or 180 degrees) in response to the device  1000  being rotated. 
     The electronic device  1000  also includes a processor  1006  operably connected with a computer-readable memory  1002 . The processor  1006  may be operatively connected to the memory  1002  component via an electronic bus or bridge. The processor  1006  may be implemented as one or more computer processors or microcontrollers configured to perform operations in response to computer-readable instructions. The processor  1006  may include a central processing unit (CPU) of the device  1000 . Additionally, and/or alternatively, the processor  1006  may include other electronic circuitry within the device  1000  including application specific integrated chips (ASIC) and other microcontroller devices. The processor  1006  may be configured to perform functionality described in the examples above. 
     The memory  1002  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  1002  is configured to store computer-readable instructions, sensor values, and other persistent software elements. 
     The electronic device  1000  may include control circuitry  1010 . The control circuitry  1010  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  1010  may receive signals from the processor  1006  or from other elements of the electronic device  1000 . 
     As shown in  FIG.  10   , the electronic device  1000  includes a battery  1014  that is configured to provide electrical power to the components of the electronic device  1000 . The battery  1014  may include one or more power storage cells that are linked together to provide an internal supply of electrical power. The battery  1014  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  1000 . The battery  1014 , via power management circuitry, may be configured to receive power from an external source, such as an alternating current power outlet. The battery  1014  may store received power so that the electronic device  1000  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  1000  includes one or more input devices  1018 . The input device  1018  is a device that is configured to receive input from a user or the environment. The input device  1018  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  1018  may provide a dedicated or primary function, including, for example, a power button, volume buttons, home buttons, scroll wheels, and camera buttons. 
     The device  1000  may also include one or more sensors or sensor modules  1020 , 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  1000  includes a sensor array (also referred to as a sensing array) which includes multiple sensors  1020 . 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  1020  may be operably coupled to processing circuitry. In some embodiments, the sensors  1020  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  1020  is used to reconfigure the display output to correspond to an orientation or folded/unfolded configuration or state of the device. Example sensors  1020  for this purpose include accelerometers, gyroscopes, magnetometers, and other similar types of position/orientation sensing devices. In addition, the sensors  1020  may include a microphone, an acoustic sensor, a light sensor (including ambient light, infrared (IR) light, and 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, or a pulse oximeter), a biometric sensor (e.g., a fingerprint sensor), or other types of sensing device. 
     In some embodiments, the electronic device  1000  includes one or more output devices  1004  configured to provide output to a user. The output device  1004  may include a display  1008  that renders visual information generated by the processor  1006 . The output device  1004  may also include one or more speakers to provide audio output. The output device  1004  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  1000 . 
     The display  1008  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  1008  is a liquid-crystal display or an electrophoretic ink display, the display  1008  may also include a backlight component that can be controlled to provide variable levels of display brightness. If the display  1008  is an organic light-emitting diode or an organic electroluminescent-type display, the brightness of the display  1008  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  1018 . 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  1000 . 
     The electronic device  1000  may also include a communication port  1012  that is configured to transmit and/or receive signals or electrical communication from an external or separate device. The communication port  1012  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  1012  may be used to couple the electronic device  1000  to a host computer. 
     The electronic device  1000  may also include at least one accessory  1016 , 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  1000  such as the control circuitry  1010 . 
     As used herein, the terms “about,” “approximately,” “substantially,” “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 “at least one 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 “at least one 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 “at least one of A, B, and C” or “at least one 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: 20201202
Publication Date: 20240213
Grant Date: 20240213
Priority Date: 20200902
Inventors: LIMARGA, Andi M.
AGRAWAL, Akanksha
TOBENA, ALBERT OCHAGAVIA
SHANNON, JASON P.
Assignee: APPLE INC
CPC Classifications: [{"code": "C03C15/00", "inventive": true, "first": true, "tree": "[]"}, {"code": "C03C17/002", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C21/002", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/3827", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C2217/72", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04M1/185", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04B1/3827", "inventive": true, "first": true, "tree": "[]"}, {"code": "C03C15/00", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04M1/0264", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/0283", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C21/002", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C21/006", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C15/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "B24B1/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C21/002", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C15/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C21/002", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C2217/72", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C17/002", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04B1/3827", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 80357828