PATENT DOCUMENT

Publication Number: US-12030818-B2
Application Number: US-202117401194-A
Country: US
Kind Code: B2

Title: Electronic devices including glass ceramic components

Abstract:
Glass ceramic components for electronic devices are disclosed, as are components including a glass ceramic material. A cover member including a glass ceramic material may be positioned over one or more device components such as an optical module or a component of a wireless communication or charging system. The cover member may have optical properties, electrical properties, magnetic properties, and/or mechanical properties compatible with the requirements of the one or more device components.

Claims:
What is claimed is: 
     
       1. An electronic device comprising:
 an enclosure comprising:
 an enclosure component defining a side surface of the enclosure; 
 a front cover assembly coupled to the enclosure component and comprising a front cover member formed from a first glass ceramic material, the front cover member having:
 an average transmission greater than or equal to 80% for visible light; 
 a haze value less than 1%; and 
 an average transmission greater than or equal to 85% for infrared light in a wavelength range from 900 nm to 1.6 micrometers; and 
 
 a rear cover assembly coupled to the enclosure component and comprising a rear cover member formed from a second glass ceramic material, the second glass ceramic material having a dielectric constant less than 30; 
 
 a display positioned below the front cover member; 
 a front-facing biometric sensor assembly positioned below the front cover member, the front-facing biometric sensor assembly including:
 an infrared emitter module configured to operate through the front cover member; and 
 an infrared image sensor configured to operate through the front cover member; and 
 
 a transceiver component of a wireless communication system positioned below the rear cover assembly. 
 
     
     
       2. The electronic device of  claim 1 , wherein:
 the transceiver component is a directional antenna configured to transmit wireless signals at a frequency band between about 25 GHz and 39 GHz; and 
 the dielectric constant of the second glass ceramic material ranges from 4 to 8 over a frequency range from 5 GHz to 40 GHz. 
 
     
     
       3. The electronic device of  claim 2 , wherein:
 the directional antenna is a first directional antenna; 
 the frequency band is a first frequency band; 
 the electronic device further comprises a second directional antenna positioned below the front cover assembly and configured to transmit wireless signals at a second frequency band between about 25 GHz and 39 GHz; and 
 the first glass ceramic material has a dielectric constant ranging from 4 to 8 over the frequency range from 5 GHz to 40 GHz. 
 
     
     
       4. The electronic device of  claim 1 , wherein:
 the rear cover member defines a protruding region having a raised plateau surface and an array of openings extending into the raised plateau surface; and 
 the electronic device further comprises a rear sensing array including an array of camera modules, each camera module of the array of camera modules positioned in a respective opening of the array of openings. 
 
     
     
       5. The electronic device of  claim 4 , wherein the rear sensing array further comprises an infrared sensor module configured to estimate a distance between the electronic device and an object. 
     
     
       6. The electronic device of  claim 1 , wherein:
 the front cover member has a color characterized by an a* value having a magnitude less than 1 and by a b* value having a magnitude less than 2; and 
 the haze value is less than or equal to 0.2%. 
 
     
     
       7. The electronic device of  claim 1 , wherein:
 the front cover member defines an opening over a speaker; 
 the infrared emitter module projects a spatial pattern of the infrared light; and 
 the infrared image sensor is configured to produce an image from a reflection of the infrared light. 
 
     
     
       8. An electronic device comprising:
 a display; 
 a front-facing biometric sensor assembly comprising:
 an emitter module configured to emit an optical signal in an infrared range from 900 nm to 1.6 microns; and 
 a receiver module configured to detect a reflection of the optical signal and comprising an image sensor; and 
 
 an enclosure comprising:
 an enclosure component; 
 a front cover assembly coupled to the enclosure component and comprising a glass ceramic cover member positioned over the display and the front-facing biometric sensor assembly, the glass ceramic cover member having:
 a haze value less than 0.5%; and 
 greater than or equal to 85% average transmission over the infrared range; and 
 
 a rear cover assembly coupled to the enclosure component and including a cover member comprising a translucent portion. 
 
 
     
     
       9. The electronic device of  claim 8 , wherein:
 the electronic device further comprises a rear-facing camera array comprising an array of camera modules; 
 the rear cover assembly defines an array of through-holes; and 
 each camera module of the array of camera modules extends into a respective through-hole of the array of through-holes. 
 
     
     
       10. The electronic device of  claim 9 , wherein the rear cover assembly further comprises at least one transparent window member coupled to the cover member and positioned over at least one through-hole of the array of through-holes. 
     
     
       11. The electronic device of  claim 8 , wherein:
 the glass ceramic cover member of the front cover assembly is formed of a first glass ceramic material; and 
 the cover member of the rear cover assembly is formed of a second glass ceramic material different from the first glass ceramic material. 
 
     
     
       12. The electronic device of  claim 11 , wherein the translucent portion of the cover member of the rear cover assembly includes a first crystal size at an exterior surface region and a second crystal size, larger than the first crystal size, in an interior region. 
     
     
       13. The electronic device of  claim 8 , wherein the glass ceramic cover member has a thickness from 250 microns to 1.5 mm. 
     
     
       14. The electronic device of  claim 8 , wherein a portion of the glass ceramic cover member positioned over the display has a greater than or equal to 85% transmission for visible light. 
     
     
       15. An electronic device comprising:
 a display; 
 a sensing array including a biometric sensor assembly, the biometric sensor assembly comprising at least one infrared light-emitting module and at least one infrared image sensor; and 
 an enclosure comprising:
 an enclosure component defining a side surface of the electronic device; and 
 a cover assembly defining a front surface of the electronic device, the cover assembly comprising a cover member positioned over the display and the sensing array, formed from a glass ceramic material, and having:
 an average transmission that is greater than or equal to 85% for visible light over a range from 400 nm to 700 nm; 
 an average transmission that is greater than or equal to 85% for light over a range from 900 nm to 1.6 microns; 
 a haze value less than 0.5%; and 
 a color described by an L* value of 90 or more, an a* value having a magnitude less than 0.5, and a b* value having a magnitude less than 1. 
 
 
 
     
     
       16. The electronic device of  claim 15 , wherein:
 the cover assembly is a first cover assembly, the cover member is a first cover member, and the glass ceramic material is a first glass ceramic material; 
 the enclosure component defines an opening along the side surface; 
 the electronic device further comprises a second cover assembly including a second cover member formed from a second glass ceramic material and positioned within the opening; and 
 the electronic device comprises a directional antenna assembly positioned below the second cover assembly and configured to transmit wireless signals at a frequency band between about 25 GHz and 39 GHz. 
 
     
     
       17. The electronic device of  claim 16 , wherein:
 the enclosure further comprises a third cover assembly defining a rear surface of the electronic device; 
 the third cover assembly comprises a third cover member formed from a third glass ceramic material; and 
 the electronic device further comprises a wireless charging component positioned below the third cover member. 
 
     
     
       18. The electronic device of  claim 17 , wherein each of the first glass ceramic material, the second glass ceramic material, and the third glass ceramic material has a dielectric constant from 2 to 20 in an RF frequency band. 
     
     
       19. The electronic device of  claim 17 , wherein each of the first glass ceramic material, the second glass ceramic material, and the third glass ceramic material comprises at least 10% by weight of one or more crystalline phases. 
     
     
       20. The electronic device of  claim 15 , wherein the cover member is chemically strengthened to form a compressive stress layer along a front surface of the cover 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. 63/090,375, filed Oct. 12, 2020 and titled “Electronic Devices Including Glass Ceramic Components,” the disclosure of which is hereby incorporated herein by reference its entirety. 
    
    
     FIELD 
     The described embodiments relate generally to components for electronic devices that include a glass ceramic material. More particularly, the present embodiments relate to glass ceramic enclosure components. 
     BACKGROUND 
     Many modern day portable electronic devices include a display, one or more cameras, and various optical sensors that are integrated into the device. Typically, the display and at least some of the cameras and optical sensors are positioned below a glass or plastic cover sheet. Embodiments described herein are directed to electronic device enclosures that include glass ceramic components and that may have advantages as compared to some traditional electronic device enclosures. 
     SUMMARY 
     Embodiments described herein relate generally to components for electronic devices that include a glass ceramic material. A component including the glass ceramic material may be an enclosure component of the electronic device, such as a cover member. In some embodiments, the component is a glass ceramic component. 
     The glass ceramic material may be configured to have mechanical properties which provide resistance to both breakage and scratches. For example, the glass ceramic material may be strong and tough enough so that it does not break when the electronic device is dropped. In some cases, the glass ceramic material is tougher than typical glass materials used for electronic device enclosures. The mechanical properties may include one or more of hardness, elastic modulus, fracture toughness, or impact toughness. 
     In some cases, a cover member including a glass ceramic material may be configured to have optical properties suitable for use over one or more components of the electronic device. For example, a glass ceramic cover member may have optical properties suitable for use over a sensing array of the electronic device. The sensing array may include multiple optical modules, such as a combination of sensor modules and camera modules. At least some of the optical modules may be configured to operate over different wavelength ranges, such as a visible wavelength range and an infrared (IR) wavelength range. The glass ceramic material of the cover member may have optical properties suitable for use with these different wavelength ranges. The glass ceramic material may also have optical properties suitable for use over a display. The optical properties may include one or more of a transmission value, a haze value, or a color value. 
     Alternately or additionally, a cover member including a glass ceramic material may be configured to have electrical and/or magnetic properties suitable for use over other components of the electronic device. For example, a glass ceramic cover member may be configured to have dielectric properties suitable for use over a component of a wireless communication system. In addition, a glass ceramic cover member may be configured to have magnetic properties suitable for use over a component of a wireless charging system. For example, the glass ceramic cover member may be substantially non-magnetic. 
     The disclosure provides an electronic device comprising an enclosure. The enclosure comprises an enclosure component defining a side surface of the enclosure and a front cover assembly coupled to the enclosure component and comprising a front cover member formed from a first glass ceramic material, the front cover member having greater than or equal to 80% transmission for visible light and a haze value less than 1%. The enclosure further comprises a rear cover assembly coupled to the enclosure component and comprising a rear cover member formed from a second glass ceramic material, the second glass ceramic material having a dielectric constant less than 30. The electronic device further comprises a display positioned below the front cover assembly, a front-facing camera array positioned below the front cover assembly and along a side of the display, and a transceiver component of a wireless communication system positioned below the rear cover assembly. 
     The disclosure further provides an electronic device comprising a display, a front-facing sensor assembly, and an enclosure. The front-facing sensor assembly comprises an emitter module configured to emit an optical signal over an infrared range and a receiver module configured to detect a reflection of the optical signal. The enclosure comprises an enclosure component and a front cover assembly coupled to the enclosure component and comprising a glass ceramic cover member positioned over the display and the sensor assembly, the glass ceramic cover member having a haze value less than 0.5% and a greater than or equal to 85% transmission over the infrared range. The enclosure also comprises a rear cover assembly including a cover member comprising a translucent portion. In some cases, the translucent portion may extend substantially over an entirety of the cover member of the rear cover assembly. 
     In addition, the disclosure provides an electronic device comprising a display and an enclosure comprising an enclosure component defining a side surface of the electronic device and a cover assembly defining a front surface of the electronic device. The cover assembly comprising a cover member positioned over the display, formed from a glass ceramic material, and having greater than or equal to 85% transmission for visible light, a haze value less than 0.5%, and a color described by an L* value of 90 or more, an a* value having a magnitude less than 0.5, and a b* value having a magnitude less than 1. 
    
    
     
       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. 
         FIGS.  1 A and  1 B  show views of an example electronic device. 
         FIG.  2    shows an enlarged view of a sensing array of an electronic device. 
         FIG.  3    shows a partial cross-sectional view of a sensing array. 
         FIG.  4    shows another partial cross-sectional view of a sensing array. 
         FIG.  5    shows an additional partial cross-sectional view of a sensing array. 
         FIG.  6    shows an example cross-sectional view of a rear-facing sensing array of an electronic device. 
         FIG.  7    shows an example cross-sectional view of another rear-facing sensing array of an electronic device. 
         FIG.  8    shows an example cross-sectional view of another rear-facing sensing array of an electronic device. 
         FIGS.  9 A and  9 B  show partial cross-sectional views of an electronic device. 
         FIG.  10    shows another example electronic device including a sensing array. 
         FIGS.  11 A and  11 B  show views of an additional example electronic device including a sensing array. 
         FIG.  12    shows a block diagram of a sample electronic device incorporating a glass ceramic 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 generally to components for electronic devices that include a glass ceramic material. A component including the glass ceramic material may be a component of the enclosure of the electronic device, such as a cover member. In some embodiments, the component is formed from the glass ceramic material and may be referred to as a glass ceramic component. The disclosure also relates to enclosures including these components and electronic devices including these enclosures. 
     The glass ceramic material may be configured to have mechanical properties which provide scratch and impact resistance to the enclosure. For example, the glass ceramic material may be both strong and tough. In some cases, the glass ceramic material is tougher than typical glass materials used for electronic device enclosures. In addition, the glass ceramic material may be hard enough to resist scratching. The mechanical properties may include one or more of hardness, elastic modulus, fracture toughness, or impact toughness. As referred to herein, a glass ceramic material comprises one or more crystalline phases (e.g., crystals) formed by crystallization of a (precursor) glass material. These crystalline phases can contribute to the favorable mechanical properties of the glass ceramic material. 
     In some cases, a cover member including or formed from a glass ceramic material may be configured to have optical properties compatible with the requirements of one or more components of the electronic device. For example, the cover member may have optical properties suitable for use over a sensing array of the electronic device. The sensing array may include multiple optical modules including, for example, a combination of sensor modules and/or camera modules. At least some of the optical modules may be configured to operate over different wavelength ranges, such as a visible wavelength range and an infrared (IR) wavelength range. For example, the optical modules may include a visible (light) camera, a visible (light) sensor module, an IR camera module, and/or an IR sensor module. The glass ceramic material of the cover member may have optical properties suitable for use with these different wavelength ranges. The glass ceramic material may also have optical properties suitable for use over a display. The optical properties may include one or more of a transmission value, a haze value, or a color value. In some embodiments, the cover member may be substantially transparent, translucent, opaque, or combinations thereof. 
     Alternately or additionally, a cover member including or formed from glass ceramic material may be configured to have electrical and/or magnetic properties suitable for use over other components of the electronic device. For example, the cover member may be configured to have dielectric properties suitable for use over a component of a wireless communication system. In addition, the cover member may be configured to have magnetic properties suitable for use over a component of a wireless charging system. For example, the cover member may be substantially non-magnetic. 
     In some embodiments, the electronic device enclosure includes a cover member comprising a glass ceramic material. In some cases, the cover member may be formed from the glass ceramic material and may be a glass ceramic cover member. The cover member may be positioned along a front, a rear, or a side of the electronic device. As previously discussed, the cover member may be configured to have optical properties, electrical properties, and/or magnetic properties compatible with one or more components of the electronic device. 
     In additional embodiments, the electronic device enclosure includes two cover members and at least one of the cover members comprises a glass ceramic material. The other cover member comprises a glass material, a glass ceramic material, or a combination thereof. The cover member comprising the glass ceramic material may be a front cover member, a rear cover member, or both. In some examples, one cover member is formed from a glass ceramic material and the other cover member is formed from a glass material. 
     In additional examples, the electronic device enclosure comprises a front cover member formed from a first glass ceramic material and a rear cover member formed from a second glass ceramic material. In some cases, the front cover member may be substantially transparent or may include one or more transparent portions positioned over a display or other device component configured to operate over a visible wavelength range. In additional cases, the front cover member may define one or more openings and one or more substantially transparent window members may be placed over or in the one or more openings. In some cases, the rear cover member may be substantially transparent or may include one or more transparent portions positioned over a device component configured to operate over a visible wavelength range. In additional cases, the rear cover member may define one or more openings and one or more substantially transparent window members may be positioned over or in the one or more openings (as shown in  FIGS.  6 - 8   ). The first glass ceramic material may be substantially the same as the second glass ceramic material or may differ in composition or in the amount and/or size of crystals in the material. 
     These and other embodiments are discussed below with reference to  FIGS.  1 A through  12   . However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these figures is for explanatory purposes only and should not be construed as limiting. 
       FIGS.  1 A and  1 B  show an example of an electronic device or simply “device”  100 . For purposes of this disclosure, the device  100  may be a portable electronic device including, for example, a mobile phone, a tablet computer, a portable computer, a wearable electronic device, a portable music player, a health monitor device, a portable terminal, a wireless charging device, device accessory, or other portable or mobile device. In the example of  FIGS.  1 A and  1 B , the dimensions and form factor, including the ratio of the length of its long sides to the length of its short sides, correspond to those of a mobile phone. However, this example is not limiting, and examples of other device form factors are shown in  FIGS.  10 ,  11 A, and  11 B . 
     As shown in  FIGS.  1 A and  1 B , the electronic device  100  includes an enclosure  105 . The enclosure  105  includes a front cover assembly  122 , a rear cover assembly  124 , and an enclosure component  110 . Internal components of the device may be at least partially enclosed by the front and rear cover assemblies  122 ,  124  and the enclosure component  110  and, in some cases, may be positioned within an internal cavity defined by the enclosure (e.g.,  601  of  FIG.  6   ). The example of  FIGS.  1 A and  1 B  is not limiting and in other examples internal components of the device may be enclosed by an enclosure component in combination with a single cover or any other suitable configuration. 
     The enclosure  105  includes one or more components including a glass ceramic material. In some cases, these components are formed from the glass ceramic material and may be referred to as glass ceramic components. In some cases, the component including the glass ceramic material (e.g., the glass ceramic component) is in the form of a cover member included in the front cover assembly  122  and/or the rear cover assembly  124 . In additional cases, the component including the glass ceramic material (e.g., the glass ceramic component) may be included in the enclosure component  110 . The component including the glass ceramic material may be positioned over one or more internal components of the electronic device  100  such as a display  142 , a camera assembly  144  (which may be part of a camera array), a sensor assembly  146  (which may be part of a sensor array), a radio-frequency (RF) antenna assembly (which may be a directional antenna assembly), a component for an inductive coupling wireless charging system, or the like. 
     The glass ceramic material may be configured to have sufficient hardness, strength, and toughness to provide scratch and impact resistance to the component and to the enclosure  105 . As referred to herein, a glass ceramic material comprises one or more crystalline phases (e.g., crystals) formed by crystallization of a (precursor) glass material. These crystalline phases can contribute to the favorable mechanical properties of the glass ceramic material. The glass ceramic material may further comprise an amorphous (glass) phase and the crystals may be dispersed in the glass phase. In some examples, the amount of the crystalline phase(s) is greater than 10%, from 20% to 90%, from 30% to 90%, from 40% to 90%, from 50% to 90%, from 60% to 90%, from 70% to 90%, from 20% to 40%, from 20% to 60%, from 20% to 80%, from 30% to 60%, or from 30% to 80% of the glass ceramic material by weight. In some cases, these values may correspond to an average amount or a local amount of crystalline phase(s) in the glass ceramic component. The residual glass phase may form the balance of the material. The description of glass ceramic materials provided with respect to  FIGS.  1 A and  1 B , including, but not limited to, the description of glass ceramic compositions, crystalline phase amounts, types, and sizes, and mechanical, optical, electrical, and magnetic properties, is not limited to the example of  FIGS.  1 A and  1 B  but is generally applicable herein. 
     A component including a glass ceramic material (e.g., a glass ceramic component) may be positioned over an internal component of the electronic device  100  and may also be configured to allow transmission of electromagnetic signals to and/or from the internal component. For example, a cover member including a glass ceramic material (e.g., a glass ceramic cover member) may have a haze value, a transmission value over a specified wavelength or frequency range, a color, or other optical properties suitable for use over a camera and/or a display. As another example, the glass ceramic material of the component may be configured to be RF-transmissive and may have a dielectric constant suitable for use over a radio-frequency antenna or wireless charging system. As a further example, the glass ceramic material of the component may have a magnetic permeability sufficiently low that it does not interfere with transmission of magnetic fields generated by the inductive coupling wireless charging system. 
     The component including a glass ceramic material (e.g., the glass ceramic component) may be substantially transparent, translucent, opaque, or include transparent, translucent, or opaque portions. For example, a transparent glass ceramic component may be formed from a glass ceramic material having crystals whose size is smaller than wavelengths of visible light (e.g., smaller than about 100 nm). In addition, the difference in refractive index between crystals and the glass phase may be relatively small. As referred to herein, an enclosure component formed from a particular material, such as a glass ceramic component, may also include a small amount of another material, such as a relatively thin coating of a different material along one or more surfaces. 
     In some cases, glass ceramic components or portions may be formed from glass ceramic materials having crystals which produce scattering of visible light. Such glass ceramic components or portions may be configured to affect transmission of light to and/or from an optical component of the electronic device and/or may produce a translucent and/or opaque effect. The scattering may be due to a difference between the index of refraction of the crystals and another phase present in the material and/or the size of the crystals. For example, crystals having a size (e.g., diameter) about the same size as a wavelength of light may produce scattering of that light. In some examples, even smaller crystals can produce scattering, such as crystals having a size equal to the wavelength multiplied by 0.06, 0.1, or 0.3. Larger crystals may produce more forward scattering of light so in some cases it may be desirable to limit the size of the crystals, such as to a size equal to the wavelength multiplied by 0.3, 0.7, or 1.0. 
     In some embodiments, at least some of the crystals may have a size which scatters light over all or part of the visible spectrum, but scatters light of longer wavelengths to a lesser extent. For example, near-infrared wavelengths of light, such from about 800 nm to about 2.5 microns, from 900 nm to about 1.6 microns, or from about 800 nm to about 1000 nm, may be scattered to a lesser extent than visible light wavelengths. 
     In some cases, a glass ceramic portion or component may be configured to have smaller crystals near an exterior surface of the portion or component than crystals in an interior and/or near an interior surface of the portion or component. A difference in crystal size through the thickness of the portion or component may be configured to affect transmission of light to and/or from an optical component of the electronic device, to produce an optical effect, or both. For example, the smaller crystals may produce less scattering of visible light near the exterior surface than in an interior and/or near the interior surface of the portion or component, creating a depth effect. The difference in crystal sizes may be achieved through a gradient of crystal sizes through at least a portion of the thickness, through creating regions of different crystal sizes through the thickness, or both. The crystal size gradient may be uniform or may be stepped. For example, the translucent glass ceramic portion or component may have a first crystal size in an exterior surface region and a second crystal size, larger than the first crystal size, in an interior region. In some cases, the translucent glass ceramic portion or component may include a gradient region between this exterior surface region and this interior region, with the gradient region having a crystal size gradient. In some cases, the thickness of the exterior surface region, the interior region, and/or the gradient region is at least 2 microns, at least 5 microns, at least 10 microns, or at least 20 microns. 
     As an example, crystals at the exterior surface of the component (e.g., in an exterior surface region) may have a size greater than zero and less than about 200 nm or about 100 nm. In addition, crystals in the interior and/or at the interior surface of the component (e.g., in an interior surface region) may have a size greater than about 200 nm and less than about 1.5 microns, greater than about 200 nm and less than about 1 micron, greater than about 200 nm and less than about 800 nm, greater than about 400 nm and less than 1 micron, or greater than about 600 nm and less than about 1.5 microns. These crystal sizes may be average crystal sizes in a given region of the glass ceramic component. In some cases, the variation in crystal size through the thickness of the portion or component produces a haze value from 10% to 50%, from 10% to 75%, from 20% to 50%, from 20% to 75%, or from 50% to 80%. In embodiments, the difference in crystal sizes may be produced in a thicker portion of a glass ceramic component (e.g., the thicker portion  127 ), by localized heating of the thicker portion. 
     By the way of example, 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 addition to the principal elements of the glass ceramic material (e.g., aluminum, silicon, and oxygen for an aluminosilicate), the glass ceramic material may also include other elements. For example, the glass ceramic material (and the precursor glass) may include elements from nucleating agents for the glass ceramic material, such as a metal oxide (Ti, Zr) or other suitable oxide material. Aluminosilicate and boroaluminosilicate glass ceramics may further include monovalent or divalent ions, some of which may compensate charges due to introduction of aluminum ions in the material. For example, an aluminosilicate glass ceramic may include alkali metal ions such as Li +  or Na + . 
     Glass ceramic materials can form a variety of crystalline phases and glass ceramic materials useful for the components described herein which include one or more crystalline phases. For example, aluminosilicate glasses can form several types of crystalline phases, including β quartz solid solution crystals, keatite solid solution crystals (β spodumene solid solution crystals), petalite crystals, lithium disilicate crystals, and various other silicates. Other silicates include, but are not limited to, silicates including aluminum and optionally other elements such as lithium, sodium, potassium, and the like. Examples of such silicates include lithium orthoclase, lithium orthosilicate, (Li, Al, Na) orthosilicates (e.g., a or β eucryptite), and lithium metasilicate. Some of these crystalline phases can be transformed into other crystalline phases. For example, β quartz solid solution crystals can transform into keatite/β spodumene crystals. Similarly, mixtures of crystal phases can be transformed into different mixtures. 
     In some cases, the glass ceramic component is chemically strengthened by ion exchange of the glass ceramic material. For example, an ion-exchangeable glass ceramic material 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+ ) that may be exchanged for other alkali metal or alkaline earth ions. If the glass ceramic material comprises sodium ions, the sodium ions may be exchanged for potassium ions. Similarly, if the glass ceramic material comprises lithium ions, the lithium ions may be exchanged for sodium ions and/or potassium ions. The ion exchange may occur in the glass phase, in a crystalline phase, or both. Exchange of smaller ions in the glass ceramic material for larger ions can form a compressive stress layer along a surface of the glass ceramic material. Formation of such a compressive stress layer can increase the hardness and impact resistance of the glass ceramic material. In some cases, the chemically strengthened glass ceramic component is configured to have a composition stable under typical use conditions of the electronic device and under processing conditions experienced subsequent to chemical strengthening (e.g., during a subsequent coating operation). When the ion exchange introduces sodium and/or potassium ions, the concentration of sodium and/or potassium ions at or near the surface of the glass ceramic material may be limited to ensure that the ion concentration is stable under typical use conditions. For example, in some cases the sodium concentration in a surface region (e.g., about 2 microns deep) may be limited to limit or prevent corrosion through reaction with moisture in the environment. The concentration of sodium (expressed as molar percent of sodium oxide) may be less than 10% or less than 5%. 
     In embodiments, the front cover assembly  122  is substantially transparent or includes one or more substantially transparent portions over the display  142  and/or an optical component configured to operate over a visible wavelength range (e.g., an optical component of the camera assembly  144 ). As referred to herein, a component or material is substantially transparent when light is transmitted through the material and the extent of scattering is low. For example, the transmission may be at least 80%, 85%, 90%, or 95% over a visible wavelength range (e.g., the visible spectrum) and the haze may be less than about 5% or 1%. 
     The front cover assembly  122  may also include one or more translucent and/or opaque portions in combination with the one or more substantially transparent portions. For example, the front cover assembly  122  may include a translucent or opaque portion around a periphery of the front cover assembly (e.g., extending inward from a side surface of the front cover assembly). As another example, the front cover assembly  122  may include a translucent or opaque portion around a periphery of an opening (e.g., the opening  135 ) in the front cover assembly  122 . Further the front cover assembly  122  may include a translucent or opaque portion over a device component which is configured to operate over a range other than a visible wavelength or frequency range (e.g., an infrared (IR) wavelength range or a radio-frequency (RF) range). The translucent or opaque portions of the front cover assembly  122  may correspond to translucent or opaque portions of the cover member  132  and/or may correspond to portions where a translucent or opaque coating has been applied to the cover member  132 . 
     In the example of  FIG.  1 A , the front cover assembly  122  includes a cover member  132  (also referred to herein as a front cover member). In some cases, the cover member  132  may be formed from a glass ceramic material. In additional cases, the cover member  132  may include one or more glass portions and one or more glass ceramic portions or may be formed from a glass ceramic layer in combination with one or more of a glass layer, a ceramic layer, or a polymer layer. In some cases, the ceramic layer may be substantially transparent, such as a sapphire layer. Typically, the cover member  132  is substantially transparent or includes one or more substantially transparent portions over a display and/or an optical component configured to operate over a visible wavelength range. The cover member  132  may also include one or more translucent and/or opaque portions in combination with the one or more substantially transparent portions. As previously described for the front cover assembly  122 , the cover member  132  may include a translucent or opaque portion around a periphery of the cover member or around a periphery of an opening in the cover member. Further, the cover member  132  may include a translucent or opaque portion over a device component which is configured to operate over a range other than a visible wavelength or frequency range or over a device component of an inductive coupling wireless charging system. 
     The front cover assembly  122  may also include an exterior coating such as an oleophobic coating and/or an anti-reflective coating. Alternately or additionally, the front cover assembly  122  may include an interior coating such as a masking layer which provides an opaque portion of the front cover assembly  122 . In addition, the front cover assembly may include a mounting frame which is coupled to an interior surface of the cover member  132  and to the enclosure component  110 . 
     The front cover assembly  122  may at least partially define a front surface  102  of the electronic device. In the example of  FIG.  1 A , the front cover assembly may define a substantial entirety of the front surface  102  of the electronic device. In some embodiments, the cover member  132  has a thickness less than 3 mm, less than or equal to 2 mm, less than or equal to 1 mm, from about 250 microns to about 1 mm, or from about 500 microns to about 1 mm. 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. 
     In some cases, each of the front cover assembly  122  and the cover member  132  is positioned over the display  142 , the camera assembly  144 , and the sensor assembly  146 . In other cases, the front cover assembly  122  may be positioned over the display  142 , the camera assembly  144 , and the sensor assembly  146 , while the cover member  132  defines an opening over one or more of the camera assembly  144 , and the sensor assembly  146  (as shown in  FIG.  4   ). An opening  135  is provided in the front cover  122  and the cover member  132  and in some cases may provide a speaker port. The front cover assembly  122  and the cover member  132  may also be positioned over a component  181 , which may be part of a wireless communication system. 
     The cover member  132  may be configured to provide optical properties suitable for use over the display  142 , the camera assembly  144 , and the sensor assembly  146 . For example, these optical properties may include one or more of a haze value, a color value, or a transmission value. For example, the cover member  132  may be configured to have a haze value sufficiently low that the optical input to an optical module of the camera assembly  144  and/or the optical output provided by the display  142  is not significantly degraded. Similarly, the cover member  132  may be configured to have a sufficiently neutral color that the optical input to an optical module of the camera assembly  144  and/or the optical output provided by the display  142  is not significantly degraded. Further, the cover member  132  may be configured to have a sufficiently high transmission value over the wavelength range of operation of the camera assembly, display, and/or sensor assembly. In some cases, different portions of the cover member  132  may have different optical property ranges, as discussed in more detail below. The description of optical property ranges provided with respect to  FIG.  2    is generally applicable herein and, for brevity, is not repeated here. 
     The cover member  132  may also be configured to provide electrical properties suitable for use over a component of a wireless communication device, such as the component  181 . For example, the cover member  132  may be a dielectric cover member and may be formed from a material having a dielectric constant and a dissipation factor sufficiently low to allow transmission of RF or IR (e.g., near-IR) signals through the cover member. 
     The electronic device  100  includes a display  142 . The front cover assembly  122  is positioned over the display  142 . As previously discussed, the front cover assembly  122  may be substantially transparent or include one or more substantially transparent portions over the display and/or an optical component configured to operate over a visible wavelength range. The enclosure  105  may at least partially surround the display  142  and may enclose the display  142 . The display  142  may produce graphical output which is transmitted through a substantially transparent portion of the front cover assembly. In some cases, the display  142  is a touch sensitive display. The display  142  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. In some embodiments, the display  142  may be attached to (or may abut) the front cover assembly  122 . 
     The electronic device  100  further includes multiple sensing arrays. As referred to herein, a sensing array may include one or more camera assemblies (e.g., a camera array), one or more sensor assemblies (e.g., a sensor array), an illumination assembly, or combinations of these. The front sensing array  118  includes a front-facing camera assembly  144  and a front-facing sensor assembly  146 . The front sensing array may also include another sensor assembly  145 , which in some cases may be an ambient light sensor. The rear sensing array  170  includes an array of rear-facing camera assemblies and at least one sensor assembly as described in more detail below. An illumination assembly typically includes a light source such as a flood light source or other emitter which enables various sensing modes like face recognition and digital photography. For example, one or more emitters may emit an array of beams that are reflected off various parts of the face. The reflected beams can be used to create a point or depth map of the face and used to authenticate a user. 
     The sensing array may include one or more optical modules. An optical module may include a photodetector and/or image sensor, associated electronics, one or more optical lenses, optical covers, barrels, or shrouds and associated optical elements. For example, the optical module may be a camera module, an illumination module, or a sensor module. The sensing array may define any number of optical modules such as one, two, three, four, five, or six optical modules. 
     As shown in  FIGS.  1 A and  1 B , the electronic device  100  includes multiple camera assemblies. For example, the electronic device  100  may include a front-facing camera assembly  144  and a rear-facing camera array. Each camera assembly may include a camera module (e.g., the optical module  177  shown in  FIG.  1 B ). An array of camera assemblies (also referred to herein as a camera array) typically includes multiple camera modules and one or more illumination modules. When the camera array includes multiple camera modules, each of the camera modules may have a different field of view or other optical property. For example, a camera module may be configured to produce an image from visible light or infrared light. The multiple camera modules may be also referred to as a set of camera modules and in some cases may form an array of camera modules. 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. 
     The electronic device  100  further includes one or more sensor assemblies. As shown in  FIG.  1 A , the electronic device  100  includes one or more front-facing sensor assemblies  146 . The device  100  also includes one or more rear-facing sensor assemblies as described in more detail with respect to  FIG.  1 B . A sensor assembly may also be referred to herein simply as a sensor. Examples of sensor (assemblies) include, but are not limited to, a proximity sensor, a light sensor (e.g., an ambient light sensor), a biometric sensor (e.g., a face or fingerprint recognition sensor or a health monitoring sensor), a depth sensor, or an imaging sensor. Other examples of sensors include a microphone or a similar type of audio sensing device, a radio-frequency identification chip, a touch sensor, a force sensor, an accelerometer, a gyroscope, a magnetometer, such as a Hall-effect sensor or other magnetic sensor, or similar types of position/orientation sensing devices. When the sensor is an optical sensor, the sensor may operate over a particular wavelength range such as a visible, an infrared, or an ultraviolet wavelength range. In some cases, the optical sensor is a reflectance sensor. The electronic device may further include a processing unit (also, processor) that computes a value based on a signal from the sensor. 
     In some cases, one or more sensors may be grouped with one or more camera assemblies. As examples, the one or more sensors may be a depth measuring sensor (e.g., a time of flight sensor), an ambient light sensor, a facial recognition sensor, an infrared sensor, an ultraviolet light sensor, a health monitoring sensor, a biometric sensor (e.g., a fingerprint sensor), or the like. These sensors may be provided proximate to one or more optical modules of a camera array, as shown in  FIG.  1 B . The additional description of sensor assemblies, camera assemblies, and processors provided with respect to  FIGS.  2  through  4    is generally applicable herein and, for brevity, is not repeated here. 
     In addition, the electronic device  100  may include one or more device components that may be part of a wireless communication system, such as the device components  181 ,  183 , and  185 . As examples, the wireless communication system may be a RF or an IR communication system. In some cases, the device components  181 ,  183 , and  185  are antenna assemblies, also referred to herein simply as antennas. An RF communication system may operate at one or more of a “low band” frequency range (e.g., 600 MHz to 700 MHz), a “mid-band” frequency range (e.g., a frequency below 6 GHz (sub-6 GHz), 2.5 GHz to 3.5 GHz, or a “high-band” frequency range (e.g., 24 GHz to 39 GHz, 57 to 64 GHz, or 64 to 71 GHz). As previously discussed, a component of an RF communication system may include an RF antenna configured to radiate a radio-frequency (RF) signal. The RF antenna may be configured to operate at one or more desired RF frequency ranges or RF frequency bands. 
     In some cases, the electronic device  100  may include one or more groups of antennas that include elements that are configured to communicate via a 5G wireless protocol (including millimeter wave and/or 6 GHz communication signals). 5G communications may be achieved using various different communications protocols. For example, 5G communications may use a communications protocol that uses a frequency band below 6 GHz (also referred to as the sub-6 GHz spectrum). As another example, 5G communications may use a communications protocol that uses a frequency band above 24 GHz (also referred to as the millimeter-wave spectrum). Further the particular frequency band of any given 5G implementation may differ from others. For example, different wireless communications providers may use different frequency bands in the millimeter-wave spectrum (e.g., one provider may implement a 5G communications network using frequencies around 28 GHz, while another may use frequencies around 39 GHz). The antenna group(s) may be configured to allow communications via one or multiple of the frequency bands that implement 5G communications. 
     In some cases, the electronic device  100  includes one or more directional antennas (or high gain antennas). Accordingly, the antenna gains of the directional antennas may be highest along particular directions. A directional antenna may include an array of transceiver elements that are used to form the shapes and orientations of the radiation patterns (or lobes) of the antenna, which may be a millimeter wave antenna. The electronic device  100  may include multiple directional antennas which have different primary transmission directions, as explained further with respect to  FIGS.  9 A and  9 B . 
     The enclosure component  110  may at least partially define a side surface  106  of the electronic device  100  and may also be referred to herein as a housing. An enclosure component used in combination with front and rear cover assemblies as shown in  FIGS.  1 A and  1 B  may also be referred to as a band. The enclosure component  110  may include one or more members. In the example of  FIGS.  1 A and  1 B , the enclosure component includes multiple members formed from a metal material (e.g., one or more metal segments). In particular, the enclosure component  110  is formed from a series of metal segments ( 112   a ,  112   b ,  112   c , and  112   d ) that are separated by dielectric segments ( 114   a ,  114   b ,  114   c , and  114   d ) that provide some extent of electrical isolation between adjacent metal segments (e.g., by preventing electrical conduction through the dielectric segments). For example, a polymer segment ( 114   b ) may be provided between a pair of adjacent metal segments ( 112   a ,  112   c ). One or more of the metal segments may be coupled to internal circuitry of the electronic device  100  and may function as an antenna for sending and receiving wireless communication. In alternate embodiments, the enclosure component  110  may include one or more members formed from a glass material, one or more members formed from a ceramic material, one or more members formed from a glass ceramic material, combinations of these or combinations of these with one or more members formed from a metal material. The example of  FIGS.  1 A and  1 B  is not limited, and in other examples the enclosure component  110  may have a different number of members or may be of unitary construction (e.g., a unibody). As referred to herein, an enclosure component or member formed from a particular material, such as a metal material, may also include a relatively thin coating of a different material along one or more surfaces, such as an anodization layer, a physical vapor deposited coating, a paint coating, a primer coating (which may include a coupling agent), or the like. 
     The enclosure component  110  may define one or more openings or ports. In the example of  FIGS.  1 A and  1 B , the metal segment  112   c  of the enclosure component  110  defines the openings  116  and  117 . The opening  116  may allow (audio) input or output from a device component such as a microphone or speaker. The opening  117  may contain an electrical port or connection. In addition, the electronic device  100  may include one or more input devices. In the example of  FIGS.  1 A and  1 B , the input devices  152  and  154  have the form of a button and may extend through additional openings in the enclosure component  110 . In some cases, the electronic device  100  also includes a support plate and/or other internal structural components that are used to support internal electronic circuitry or electronic components. 
     In some cases, the enclosure component  110  may include one or more members  115  positioned within a metal member (e.g.,  112   a ). In some cases, the member  115  may provide a window for the device component  185 , may define a portion of a waveguide, and/or allow for beam-forming or beam-directing functionality. For example, the member  115  may define an antenna window for transmitting and receiving wireless signals. The member  115  may be configured to transmit wireless signals at one or more of the frequencies previously discussed with respect to the device components  181 ,  183 , and  185 . For example, the member  115  may be configured to transmit wireless signals at a frequency band between about 25 GHz and 39 GHz. 
     The member  115  may include a cover member  136 . The cover member  136  may be formed from a dielectric material. In some cases, the cover member  136  may be formed from a glass ceramic material, may include one or more glass ceramic portions or may be formed from a glass ceramic layer in combination with one or more of a glass layer, a ceramic layer, or a polymer layer. In additional cases, the cover member  136  may be formed from a glass material, a ceramic material, a polymeric material, or combinations thereof. The cover member  136  may be substantially transparent, translucent, opaque or include transparent, translucent and/or opaque portions. Further the member  115  may also include one or more coatings along the interior and/or exterior of the cover member  136 . These coatings may be similar to those described for the cover members  132  and  134 . 
     The rear cover assembly  124  may at least partially define a rear surface  104  of the electronic device. In the example of  FIG.  1 B , the rear cover assembly  124  may define a substantial entirety of the rear surface  104  of the electronic device. The rear cover assembly  124  includes a cover member  134 . In some cases, the rear cover assembly  124  also includes at least one (optically) transparent window member. In the example of  FIG.  1 B , the rear cover assembly  124  is positioned over the device component  182 , which may be a wireless charging component, and the device component  183 , which may be a wireless communication component. 
     The rear cover assembly  124  may be substantially transparent or may include one or more substantially transparent portions (e.g., over an optical component  177  configured to operate over a visible wavelength range). The rear cover assembly  124  may also include one or more translucent and/or opaque portions in combination with the one or more substantially transparent portions. For example, the rear cover assembly  124  may include a translucent portion over a device component which is configured to operate over a range other than a visible wavelength or frequency range (e.g., an infrared (IR) wavelength range or a radio-frequency (RF) range). Similarly, the rear cover assembly  124  may include a translucent or opaque portion over a device component  182  of an inductive coupling wireless charging system. In addition, the rear cover assembly  124  may include a translucent or opaque portion around a periphery of the cover member, around a periphery of an opening in the rear cover assembly, in the vicinity of the sensing array  170 , and/or surrounding the sensing array  170 . The translucent or opaque portions of the rear cover assembly  124  may correspond to translucent or opaque portions of the cover member  134  and/or may correspond to portions where a translucent or opaque coating has been applied to the cover member  134 . 
     As previously discussed, the rear cover assembly  124  includes a cover member  134  (also referred to herein as a rear cover member). In some cases, the cover member  134  may be formed from a glass ceramic material. In additional cases, the cover member  134  may be formed from a glass material, may include one or more glass portions and one or more glass ceramic portions, or may be formed from a glass ceramic layer in combination with one or more of a glass layer, a ceramic layer, or a polymer layer. In some cases, the ceramic layer may be substantially transparent, such as a sapphire layer. The cover member  134  may be substantially transparent or may include one or more substantially transparent portions (e.g., over an optical component configured to operate over a visible wavelength range). The cover member  134  may also include a translucent or opaque portion in a similar fashion as previously described for the rear cover assembly  124 . In some cases, 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. In other cases, the cover member  134  may define an opening and the rear cover assembly  124  may include an additional cover member positioned over or within the opening, as described further below and with respect to  FIG.  7   . 
     The rear cover assembly  124  may also include one or more coatings. For example, the rear cover assembly  124  may include an exterior coating such as an oleophobic coating. Alternately or additionally, the rear cover assembly  124  may include an interior coating which provides a decorative effect, such as an ink layer or metal layer. In addition, the rear cover assembly  124  may include a mounting frame which is coupled to an interior surface of the cover member  134  and to the enclosure component  110 . 
     In the example of  FIG.  1 B , the rear cover assembly  124  defines a thinner portion  125  and a thicker portion  127 . As shown in  FIG.  1 B , the thicker portion  127  of the cover assembly  124  protrudes or is offset with respect to a thinner portion  125  of the cover assembly  124 . The portion of the thicker portion  127  which protrudes with respect to the thinner portion  125  may also be referred to as a protruding region (as noted in the cross-sectional view of  FIGS.  6  and  7   ). The thicker portion  127  may define a raised surface  128  (also referred to as a top surface) and a side surface  129  while the thinner portion  125  may define a surface  126 . 
     In some cases, the cover assembly  124  is configured to produce optical contrast between the raised surface  128  and the surface  126 . For example, the raised surface  128  may appear more transparent than the surface  126  (or vice versa). As an additional example, the raised surface  128  may have a different texture than the surface  126  and the texture difference may produce an optical effect. For example, a smooth (polished) texture on the raised surface  128  may reflect more light than a rougher texture on the surface  126  (or vice versa). In some cases, the raised surface  128  may have a root mean square height less than that of the surface  126 , as explained in more detail with respect to  FIG.  6    and this description is generally applicable herein. In additional cases, similar textures may be provided on the surfaces  126  and  128 . 
     In some cases, the cover member  134  may define a corresponding thicker portion and thinner portion, with the thicker portion being integrally formed with the thinner portion. In additional cases, the thinner portion  125  may be provided by the cover member  134  while the thicker portion  127  may be provided at least in part by an additional cover member which is coupled to the thinner portion. For example, the cover member  134  may define an opening and the rear cover assembly  124  may include an additional cover member positioned within the opening as described with respect to  FIG.  8    or additional cover members positioned over and within the opening as described with respect to  FIG.  7   . 
     In some cases, the thicker portion  127  may have a thickness greater than about 1 mm and less than or equal to about 2.5 mm or greater than about 1 mm and less than or equal to about 2 mm and the thinner portion  125  may have a thickness from about 250 microns to about 1 mm, or from about 500 microns to about 1 mm. The amount of protrusion or offset between the raised surface  128  and the surface  126  may be from about 0.5 mm to about 1.5 mm. The size of the thicker portion  127  may depend at least in part on the size of the sensing array  170 . In some embodiments, a lateral dimension (e.g., a width) of the thicker portion  127  may be from about 5 mm to about 30 mm or from about 10 mm to about 20 mm. 
     The thicker portion  127  may accommodate one or more components of a sensing array  170 . For example, the sensing array  170  may include multiple camera assemblies. Each of the camera assemblies may include an optical component such as the optical component  177  or the optical component  178 . The optical component  177  may be positioned at least partially within an opening in the thicker portion  127 , as shown for optical component  677  in  FIG.  6   . The optical component  177  may be a camera module while the optical component  178  may be an illumination module. 
     In addition, the sensing array  170  may include one or more sensor assemblies, such as the sensor assembly  179 . In some cases, the sensor assembly  179  may measure a distance to a target, such as a Lidar sensor assembly which is configured to illuminate an object with light and then detect the reflected light to determine or estimate the distance between the electronic device and the object (e.g., a time of flight (TOF) sensor). In some examples the sensor assembly  179  may be positioned below the cover member  134  (and the cover member  134  may act as a window for the sensor assembly  179 ). In these examples, the optical properties of the cover member  134  may be suitable for use over one or more optical components of the sensor assembly. For example, the one or more optical components may operate over one or more specified wavelength ranges and the cover member  134  may be configured to have a suitable transmission/transmittance over these wavelength ranges. In other examples, the cover member  134  may define an opening over the sensor assembly and an additional cover member may be placed in or over the opening (and act as a window for the sensor assembly). 
     In some cases, a sensor assembly may include one or more optical modules. For example, the sensor assembly may include an emitter module, a receiver module, or both. The thicker portion  127  may also include a sensor assembly  180  which is other than an optical component. For example, the sensor assembly  180  may be a microphone which may be positioned at least partially within or below an opening in the thicker portion  127 . In implementations in which the thicker portion  127  is used to protect one or more sensor modules or components, the thicker portion  127  and/or the protruding region of the thicker portion  127  may be referred to as a sensor feature, a camera feature, a sensing array, a camera panel, and/or a camera bump. 
     The cover member  134  may be configured to provide electrical properties suitable for use over a component of a wireless communication, such as the component  183 . For example, the cover member  134  may be a dielectric cover member and may be formed from a material having a dielectric constant and a dissipation factor sufficiently low to allow transmission of RF or IR (e.g., near-IR) signals through the cover member. 
     Alternately or additionally, the cover member  134  may be formed from a material having magnetic properties suitable for use over a component of an inductive coupling wireless charging system. In particular, the cover member  134  may be formed from a material having a magnetic permeability sufficiently low that it does not interfere with transmission of electromagnetic fields generated by the inductive coupling wireless charging system. In some cases, the cover member  134  may be substantially non-magnetic. For example, the component of an inductive coupling wireless charging system may include a wireless receiver component such as a wireless receiver coil or other feature of the wireless charging system. The description of magnetic property ranges provided with respect to  FIG.  2    is generally applicable herein and, for brevity, is not repeated here. In alternate embodiments, the wireless charging system may be a radio frequency wireless charging system rather than an inductive coupling wireless charging system. The cover member  134  may thus be configured to have dielectric properties suitable for use with a radio frequency wireless charging system, which in some cases may be similar to those suitable for use with a radio frequency wireless communication system. In some cases, a radio frequency wireless charging system may operate at a frequency range from about 80 kHz to about 300 kHz or from about 110 kHz to about 205 kHz. The description of electrical property ranges provided with respect to  FIG.  2    is generally applicable herein and, for brevity, is not repeated here. 
       FIG.  2    shows an enlarged view of a sensing array of an electronic device. The electronic device  200  may be an example of the electronic device  100  of  FIGS.  1 A and  1 B . The electronic device  200  includes a sensing array  218 . The sensing array  218  includes a proximity sensor  246 , a microphone  247 , an ambient light sensor  245 , and a camera assembly  244 . In the example of  FIG.  2   , the proximity sensor  246 , the ambient light sensor  245 , and the camera assembly  244  are positioned below the cover assembly  222 , as schematically indicated by the dashed lines. The microphone  247  may be positioned below the opening  235 . The sensing array  218  may be located on any suitable surface  202  of the electronic device, such as a front surface or a rear surface. In the example of  FIG.  2   , the electronic device includes a display  242 , but in other examples a display need not be included proximate the sensing array  218 . 
     The cover assembly  222  includes a cover member  232 . In some cases, the cover member  232  may be formed from a glass ceramic material. In additional cases, the cover member  232  may include one or more glass portions and one or more glass ceramic portions or may be formed from a glass ceramic layer in combination with one or more of a glass layer, a ceramic layer, or a polymer layer. The cover assembly  222  is part of the enclosure  205 , which also includes an enclosure component  210 . The cover assembly  222 , the cover member  232 , the enclosure  205 , and the enclosure component  210  may be similar to the cover assembly  122 , the cover member  132 , the enclosure  105 , and the enclosure component  110  described with respect to  FIG.  1 A , and for brevity, those details are not repeated here. 
     The camera assembly  244  typically includes a camera module (e.g., the camera modules  377  and  477  in the cross-section view of  FIGS.  3  and  4   ). The camera module of the camera assembly  244  may produce images from visible light. However, the electronic device  200  may also include an optical module that is configured to operate over an IR range, such as a near-IR camera module. In such a case, the optical properties of the cover member  232  may be suitable for optical components configured to operate over both a visible wavelength range and a near-IR range. The camera assembly  244  may be positioned along a side of the display  242 . 
     In some cases, a camera module includes an optical sensing array and/or an optical component such as a lens, filter, or window. In additional cases, a camera module includes an optical sensing array, an optical component, and a camera module housing surrounding the optical sensing array and the optical components. The camera module may also include a lens assembly, which may include moving elements and/or moving lenses. For example, a focusing assembly may include an actuator for moving a lens of the camera module. In some cases, the optical sensing array may be a complementary metal-oxide semiconductor (CMOS) array or the like. 
     In some cases, a cover member  232  is suitable for use over a camera module of a camera assembly  244  configured to produce images from visible light. Such a cover member  232  may have a haze value less than 1%, less than 0.8%, from 0.05% to less than 0.8%, from 0.1% to less than 0.8%, from 0.2% to less than 0.8%, from 0.3% to less than 0.8%, from 0.4% to less than 0.8%, from 0.5% to less than 0.8%, from 0.05% to 0.6%, from 0.1% to 0.6%, from 0.2% to 0.6%, from 0.3% to 0.6%, from 0.05% to 0.5%, from 0.1% to 0.5%, from 0.2% to 0.5%, from 0.05% to 0.4%, from 0.1% to 0.4%, or from 0.2% to 0.4%. The haze value may be a transmissive haze value and typically depends on the thickness of the cover member. The thickness of the cover member  232  may be any of the thicknesses previously described with respect to the cover members  132  or  134 . The transmissive haze of the cover member  232  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 member as removed from the electronic device. In other example, the transmissive haze scattering may be measured for the cover assembly  222 . 
     In addition, a cover member  232  suitable for use over a camera module of a camera assembly  244  (which produces images from visible light) may have a transmission or transmittance over a visible wavelength range (e.g., from 400 nm to 700 nm) greater than 80%, greater than 82%, greater than 84%, greater than 85%, greater than 86%, greater than 87%, greater than 88%, greater than 89%, greater than 90%, greater than 91%, greater than 92%, greater than 93%, greater than 94%, or greater than 95%. These transmission values may be average values over the visible wavelength range. The transmission may depend upon the thickness of the cover member and the thickness of the cover member  232  may be any of the thicknesses previously described with respect to the cover members  132  or  134 . The transmission (or transmittance) over of the cover member  232  may be measured using commercially available equipment and according to ASTM or ISO standard test methods. As a non-limiting example, the efficiency of light transmission (e.g., total transmission) may be measured using a haze-gard i device available from BYK. The transmission or transmittance may be measured for the cover member as removed from the electronic device. Alternately, the transmission may be measured for the cover assembly  222 . The transmission value may depend upon the extent of absorption of the electromagnetic signal by the material of the cover member (or other component). For some measurement techniques, the transmission value may also depend upon scattering of the electromagnetic signal by the material of the cover member (or other component). 
     Further, a cover member  232  suitable for use over a camera module of a camera assembly  244  (which produces images from visible light) may have a neutral color. In some cases, coordinates in CIEL*a*b* (CIELAB) color space may be used to characterize a color of the cover member  232 . In CIEL*a*b*(CIELAB) color space, L* represents brightness, a* the position between red/magenta and green, and b* the position between yellow and blue. A broadband or semi-broadband illuminant may be used to determine the color of a portion of the cover member or cover assembly. For example, a CIE illuminant or other reference illuminant may be used. The color of the cover member  232  may be determined from transmitted light and/or reflected light when the cover member  232  is transparent or translucent. In some embodiments, the CIELAB coordinates for a given illuminant can be calculated from measurements of transmission through the cover member  232 . For example, the color may be characterized by an a* value having a magnitude less than 1, less than or equal to 0.5, less than or equal to 0.25, less than or equal to 0.1, or less than or equal to 0.05. In addition, the color may be characterized by a b* value having a magnitude less than 2, less than or equal to 1.5, less than or equal to 1, less than or equal to 0.75 or less than or equal to 0.5. The L* value may be greater than 85, greater than or equal to 90, or greater than or equal to 95. In some embodiments, haze, transmission, and/or color values suitable for use over a camera module of a camera assembly  244  configured to produce images from visible light are also suitable for use over the display  242 . 
     The proximity sensor  246  may comprise a light-emitting module and a light-receiving module, as shown in the cross-section view of  FIG.  5   . The light-emitting module of a proximity sensor may produce infrared light. In some embodiments, the light-emitting module produces near-infrared (near-IR) light such as light having a wavelength from about 800 nm to about 2.5 microns, from 900 nm to about 1.6 microns, or from about 800 nm to about 1000 nm. In some cases, the proximity sensor may be a time of flight sensor. 
     In additional cases, the cover member  232  is also suitable for use over an optical component configured to produce images from infrared light (e.g., near-IR light). As examples, the camera assembly  244  may include an IR camera module or the sensing array  218  may further include a sensor assembly comprising an IR light-emitting module which projects a spatial pattern (e.g., a pattern of dots), or a flood IR light-emitting (illuminating) module in addition to an IR camera. Such a sensor assembly may be used for biometric identification. In these cases, the cover member  232  may have a transmission over an infrared wavelength range (e.g., from 770 nm to 1000 nm) greater than 85%, greater than 86%, greater than 87%, greater than 88%, greater than 89%, greater than 90%, greater than 91%, greater than 92%, greater than 93%, greater than 94%, or greater than 95%. These transmission values may be average values over the infrared wavelength range. The transmission may depend upon the thickness of the cover member and the thickness of the cover member  232  may be any of the thicknesses previously described with respect to the cover members  132  or  134 . 
     The ambient light sensor  245  may comprise a light sensing module which can provide measurements of ambient light intensity. In some cases, the ambient light sensor can include color sensing. Although the example of  FIG.  2    shows an ambient light sensor  245  as separated from the proximity sensor  246  in other examples the ambient light sensor  245  may be packaged with the proximity sensor  246 . 
     In some cases, additional sensors may be located in the vicinity of the sensing array  218 . For example, the sensing array  218  may further include a sensor assembly comprising an IR light-emitting module which projects a spatial pattern (e.g., a pattern of dots), a flood IR light-emitting (illuminating) module, and an IR camera. Such a sensor assembly may be used for biometric identification. As an additional example, the sensing array  218  may include a sensor assembly that measures distance to a target, such as a Lidar sensor assembly which is configured to illuminate an object with light and then determine the distance to the object from the reflected light (e.g., a time of flight (TOF) sensor). Such a sensor assembly may include a light emitting module (e.g., a laser) and a receiver module and may be used in combination with a camera module. A Lidar sensor can provide a digital three-dimensional representation of the object, which can be used for multiple applications, including augmented reality (AR) and virtual reality (VR). In addition, other device components, such as a speaker, may be located in and/or below the sensing array  218 . 
       FIG.  3    schematically shows a partial cross-sectional view of a sensing array of an electrical device  300 . The sensing array  318  includes a camera assembly  344 , which may be part of a camera array. For example,  FIG.  3    may be an example partial cross-sectional view along D-D of  FIG.  2   . As shown in  FIG.  3   , the camera assembly  344  includes an optical module  377  positioned below a cover member  332  of a cover assembly  322 . In the example of  FIG.  3   , the cover member  332  is substantially uniform in thickness and composition both over the optical module  377  and surrounding the optical module. However, this example is not limiting as shown in the examples of  FIGS.  4  and  6  through  8   . In some examples, the cover member  332  may be a front cover member or a rear cover member. 
     In some cases, the cover member  332  may be formed from a glass ceramic material. In additional cases, the cover member  332  may include one or more glass portions and one or more glass ceramic portions or may be formed from a glass ceramic layer in combination with one or more of a glass layer, a ceramic layer, or a polymer layer. The cover member  332  may be similar in composition, dimensions, and other properties to the cover members  132  and  232  and, for brevity, those details are not repeated here. 
     The camera assembly  344  of  FIG.  3    also includes a support structure  386  which may be configured to hold various elements of the camera assembly  344  in place. For example, the optical module  377  may be mounted to the support structure  386 . The camera assembly  344  may also include a circuit assembly  388 , which may be mounted on a printed circuit board. The support structure  386  may also support the circuit assembly  388 . 
     In some cases, the optical module  377  is configured to produce images from visible light. In these cases, the cover member  332  may have optical properties (e.g., haze, transmission, color) similar to those previously described with respect to the cover member  232  for camera assemblies configured to produce images from visible light. For brevity, this description is not repeated here. In some embodiments, the cover member  332  may have similar optical properties both over the optical module  377  (configured to produce images from visible light) and over the display. 
     In additional cases, the optical module  377  is configured to produce images from infrared light (e.g., near-IR light). The cover member  332  may have a transmission over an infrared wavelength range (e.g., from 770 nm to 1000 nm) greater than 85%, greater than 86%, greater than 87%, greater than 88%, greater than 89%, greater than 90%, greater than 91%, greater than 92%, greater than 93%, greater than 94%, or greater than 95%. In some cases, the cover member  332  may have a haze value less than 1%, from 0.05% to less than 1%, from 0.1% to less than 1%, from 0.2% to less than 1%, from 0.3% to less than 1%, from 0.4% to less than 1%, from 0.5% to less than 1%, from 0.6% to less than 1%, from 0.05% to 0.8%, from 0.1% to 0.8%, from 0.2% to 0.8%, from 0.3% to 0.8%, from 0.4 to 0.8%, from 0.05% to 0.6%, from 0.1% to 0.6%, from 0.2% to 0.6%, from 0.3% to 0.6%, from 0.05% to 0.5%, from 0.1% to 0.5%, from 0.2% to 0.5%, from 0.05% to 0.4%, from 0.1% to 0.4%, or from 0.2% to 0.4%. In some embodiments, the cover member  332  may have similar optical properties over the optical module  377  configured to produce images from infrared light as over the display. However, in other embodiments, the cover member  332  may have different optical properties over such an optical module  377  than over the display. For example, the cover member  332  may have a higher haze value and/or a lower transmission value for visible light over the optical module  377  than over the display (e.g., when the optical module  377  is configured to produce images from IR light). In some examples, a glass ceramic portion of the cover member positioned over the optical module  377  may have crystals which produce a greater amount of scattering than those of a glass ceramic portion of the cover member positioned over the display. 
       FIG.  4    schematically shows a partial cross-sectional view of a sensing array of an electrical device  400 . The sensing array  418  includes a camera assembly  444 , which may be part of a camera array.  FIG.  4    may be an example partial cross-sectional view along D-D of  FIG.  2   . As shown in  FIG.  4   , the camera assembly  444  includes an optical module  477  positioned below a cover assembly  422 . In the example of  FIG.  4   , the cover assembly  422  includes a cover member  432  which defines an opening  452  over the optical module  477 . The cover assembly further includes a cover member  436  which defines a window over the optical module  477 . In some cases, the cover member  436  has a lower haze and/or a higher transmission over a visible range than the cover member  432 . In some examples, the cover member  432  may be a front cover member or a rear cover member. 
     In some cases, the cover member  432  may be formed from a glass ceramic material. In additional cases, the cover member  432  may include one or more glass portions and one or more glass ceramic portions or may be formed from a glass ceramic layer in combination with one or more of a glass layer, a ceramic layer, or a polymer layer. The cover member  432  may be similar in composition, dimensions, and one or more other properties to the cover members  132  and  232  and, for brevity, those details are not repeated here. 
     In some cases, the cover member  432  may have a relatively high transmission or transmittance over a visible wavelength range (e.g., from 400 nm to 700 nm) such as a transmission or transmittance greater than 80% and less than 90%, greater than 82% and less than 90%, greater than 84% and less than 90%, or greater than 85% and less than 90%. Similarly, the cover member  432  may have a relatively low haze value, such as a haze value from 0.2% to less than 1%, from 0.3% to less than 1%, from 0.4% to less than 1%, from 0.5% to less than 1%, from 0.6% to less than 1%, from 0.2% to 0.8%, from 0.3% to 0.8%, from 0.4% to 0.8%, from 0.05% to 0.6%, from 0.2% to 0.6%, from 0.3% to 0.6%, from 0.2% to 0.5%, or from 0.2% to 0.4%. 
     In other cases, at least a portion of the cover member  432  surrounding the cover member  436  may be configured to produce light scattering in the visible range. For example, this portion of the cover member  432  may be configured to have a variation in crystal size through the thickness in a similar fashion as previously described with respect to  FIGS.  1 A and  1 B . This portion of the cover member  432  may appear translucent or may appear to have a depth effect. In some cases, this portion of the cover member  432  may have a transmission over the visible wavelength range which is less than 80% or from 20% to 75%. Alternately or additionally, the cover member  432  may have a haze value greater than about 1%, greater than about 2%, from 5% to 50%, from 5% to 75%, from 5% to 90%, from 20% to 50%, from 20% to 75%, from 20% to 90%, from 50% to 80%, or from 50% to 90%. 
     In some cases, the cover member  436  may be formed from one or more materials having a lower haze and/or a higher transmission over a specified wavelength range than the cover member  432 . For example, the cover member  436  may be formed from a substantially transparent glass material, a substantially transparent glass ceramic material, or a substantially transparent ceramic material such as sapphire. In addition, the cover member  436  may be formed from one or more of a glass layer, a glass ceramic layer, a ceramic layer, or a polymer layer. 
     In cases where the optical module  477  is configured to produce images from visible light, the cover member  436  may have optical properties (e.g., haze, transmission, color) similar to those previously described with respect to the cover member  232  (for camera assemblies configured to produce images from visible light). In cases where the optical module  477  is configured to produce images from infrared light, the cover member  436  may have optical properties (e.g., haze and transmission) similar to those previously described with respect to the cover member  332  (for optical components configured to produce images from infrared light). For brevity, this description is not repeated here. The cover member  436  may be coupled to the cover member  432  using an adhesive, a mechanical coupling device, or a combination thereof. 
     The camera assembly  444  of  FIG.  4    also includes a support structure  486  which may be configured to hold various elements of the camera assembly  444  in place. For example, the optical module  477  may be mounted to the support structure  486 . The camera assembly  444  may also include a circuit assembly  488 , which may be mounted on a printed circuit board. The support structure  486  may also support the circuit assembly  488 . 
       FIG.  5    schematically shows a partial cross-sectional view of a sensing array of an electrical device  500 . The sensing array  518  includes a reflectance sensor assembly  546 . For example,  FIG.  5    may be an example partial cross-sectional view along E-E of  FIG.  2   . 
     The electronic device  500  includes a sensor assembly  546  positioned below a cover assembly  522  and comprising an emitter module  582  and a receiver module  584 . In some cases, the sensor assembly  546  may be configured to operate in a reflective sensing mode and the sensor assembly  546  is therefore a reflectance sensor assembly. 
     As an example, the reflectance sensor assembly may be a proximity sensor. The light-emitting module of a proximity sensor may produce infrared light. In some embodiments, the emitter module  582  produces near-infrared light such as light having a wavelength from about 800 nm to about 2.5 microns, from about 900 nm to about 1.6 microns, or from about 800 nm to about 1000 nm. In some cases, the proximity sensor may be a time of flight sensor. 
     As another example, the reflectance sensor assembly may be a Lidar sensor assembly which is configured to illuminate an object with light and then determine the distance to the object from the reflected light (e.g., a time of flight (TOF) sensor). In some cases, the emitter module  582  is a laser, which may be an infrared laser. A Lidar sensor can provide a digital three-dimensional representation of the object, which can be used for multiple applications, including augmented reality (AR) and virtual reality (VR). In addition, the reflectance sensor assembly may be a biometric identification sensor. For example, the reflectance sensor assembly may include an IR light-emitting module which projects a spatial pattern (e.g., a pattern of dots), a flood IR light-emitting (illuminating) module, and an IR camera. 
       FIG.  5    also schematically shows operation of the emitter module and the receiver module. For example, light  592  from the emitter module  582  (e.g., an optical signal) may be transmitted through the cover assembly  522  to an object  515  and light reflected from the object  515  (e.g., the optical signal reflected from the object) may be detected by the receiver module  584 . In some cases, the receiver module  584  may receive only a portion of the light produced by the emitter module  582  (e.g., a first portion of the light). 
     The cover assembly  522  includes a cover member  532  which extends over the sensor assembly  546 . In some cases, the cover member  532  may be formed from a glass ceramic material. In additional cases, the cover member  532  may include one or more glass portions and one or more glass ceramic portions or may be formed from a glass ceramic layer in combination with one or more of a glass layer, a ceramic layer, or a polymer layer. When the reflectance sensor is configured to emit and detect infrared light (e.g., near-IR light), the cover member  532  may have optical properties similar to those of the cover member  332  (when provided over an optical module configured to produce images from infrared light). The cover member  532  may be similar in composition, dimensions, and other properties to the cover members  132 ,  232 , and  332  and, for brevity, those details are not repeated here. 
     As shown in  FIG.  5   , the emitter module  582  and the receiver module  584  may be spaced apart from the cover assembly  522  by a gap  561 . The size of the gap  561  has been exaggerated in  FIG.  5    to more conveniently illustrate the light path. The emitter module may include a light emitting element  581 , which may be a light-emitting diode (LED) or a laser such as a vertical-cavity surface-emitting laser (VCSEL). The receiver module  584  may include a light receiving element  585 , which may be a photodetector, which may include one or more photodiodes, phototransistors, or other optically sensitive elements. In addition, the emitter module  582  and the receiver module  584  may be supported by a support  587 , which may include a circuit assembly or other supporting structure. It should be understood that the form of the support  587  is not limiting and that the sensor assembly  546  may include additional elements not shown in  FIG.  5   , such as circuitry and additional packaging for the emitter and receiver modules. 
       FIG.  6    shows an example cross-sectional view of a sensing array of an electronic device.  FIG.  6    shows a sensing array  670  which may be located at the rear of the electronic device  600  and may be an example cross-sectional view along B-B of  FIG.  1 B . The sensing array  670 , which may also be described as a rear-facing sensing array, includes a rear-facing camera array  675 . At least one of the optical modules of the camera array  675  is configured to operate over a visible wavelength range. The electronic device  600  includes an enclosure  605  which comprises a rear cover assembly  624 . The electronic device also includes an enclosure component  610  which defines a side surface of the electronic device. The enclosure component may include a member  612 . 
     The rear cover assembly  624  includes a cover member  634 . The sensing array  670  includes rear-facing optical modules  677  and  678 . In the example of  FIG.  6   , the rear cover member  634  does not extend over the optical modules  667  and  668 . Instead, the cover member  634  defines through-holes  667  and  668  and the optical modules  677  and  678  extend at least partially into these through-holes. Windows  687  and  688  extend over the optical modules  677  and  678  (and over the through-holes  667  and  668 ). The windows  687  and  688  may be formed of a transparent glass ceramic, a transparent ceramic such as sapphire, or glass. The rear cover member  634  may extend over a component of a wireless communication and/or charging system, as illustrated in  FIG.  9 A . The cover member  634  may include an external coating, an internal coating, or a combination thereof as described in more detail below. 
     The cover member  634  may be formed from a glass material, may be formed from a glass ceramic material, may include one or more glass portions and one or more glass ceramic portions, or may be formed from a glass ceramic layer in combination with one or more of a glass layer, a ceramic layer, or a polymer layer. In some cases, the cover member  634  includes a glass ceramic material. 
     The cover member  634  may be positioned over one or more internal components of the electronic device  600  and may also be configured to allow transmission of electromagnetic signals to and/or from the internal component. As an example, a glass ceramic material of the cover member  634  may be configured to be RF-transmissive and may have a dielectric constant suitable for use over a radio-frequency antenna or wireless charging system. In some cases, the material or combination of materials of the cover member  634  may have a dielectric constant (also referred to as the relative permittivity) having a value greater than or equal to 1 and less than 30, less than 20, less than 10, less than 7, or less than 5. In some cases, the dielectric constant may be from 3 to 7 or 4 to 8. In some cases, the loss tangent may range from about 0.002 to about 0.05, or from about 0.002 to about 0.025. In some cases, these values are maximum values while in other cases these values are measured at the frequency range(s) of interest. As an example, the frequency range of interest may be from about 5 GHz to about 40 GHz. These values may be measured at room temperature. As a further example, the glass ceramic material of the cover member  634  may have a magnetic permeability sufficiently low that it does not interfere with transmission of magnetic fields generated by the inductive coupling wireless charging system. In some cases, the cover member  634  may be substantially non-magnetic. 
     The cover member  634  may be substantially transparent, translucent, opaque or include transparent, translucent, and/or opaque portions. In some cases, the cover member  634  may have a haze greater than the cover member  632 , such as greater than about 1%, greater than about 2%, from 5% to 50%, from 5% to 75%, from 5% to 90%, from 20% to 50%, from 20% to 75%, from 20% to 90%, from 50% to 80%, or from 50% to 90%. In addition, the cover member  634  may have optical properties (e.g., transmission/transmissivity) configured to allow transmission of an optical signal through the cover member  634 . For example, when the sensing array  670  includes a sensor module that transmits an optical signal over a specified wavelength range through the cover member  634 , the cover member  634  may have a transmission similar to that of the cover members  232 ,  332 ,  432 , and  532  (for similar wavelength ranges). 
     In some cases, a glass ceramic portion or component may be configured to have smaller crystals near an exterior surface of the component than crystals in an interior and/or near an interior surface of the portion or component. For example, a glass ceramic portion or component may have a first crystal size in an exterior surface region (along the exterior surface) and a second crystal size, larger than the first crystal size, in an interior region of the glass ceramic portion or component. As examples, the interior region may be located along an interior surface of the portion or component or may be located away from the exterior and interior surfaces, such as an interior region location including a midpoint of the thickness of the portion or component. The smaller crystals may produce less scattering of visible light in the exterior surface region than in the interior region, creating a depth effect. In some cases, the difference in crystal size in the glass ceramic portion or component produces a haze value from 10% to 50%, from 10% to 75%, from 20% to 50%, from 20% to 75%, or from 50% to 80%. 
     The difference in crystal sizes may be achieved through creating regions of different crystal sizes through the thickness, through a gradient of crystal sizes from the exterior surface to the interior surface, or both. For example, the glass ceramic portion or component may include a gradient region between an exterior surface region and an interior region, with the gradient region having a crystal size gradient. The crystal size gradient may be uniform or may be stepped. As an example, crystals in an exterior surface region may have a size greater than zero and less than about 200 nm or about 100 nm. In addition, crystals in an interior surface region may have a size greater than about 200 nm and less than about 1.5 microns, greater than about 200 nm and less than about 1 micron, greater than about 200 nm and less than about 800 nm, greater than about 400 nm and less than 1 micron, or greater than about 600 nm and less than about 1.5 microns. These crystal sizes may be average crystal sizes in a given region of the glass ceramic component. In some cases, the thickness of the exterior surface region, the interior region, and/or the gradient region is at least 2 microns, at least 5 microns, at least 10 microns, or at least 20 microns. In embodiments, the difference in crystal sizes may be produced in a thicker portion of the glass ceramic component, such as in the thicker portion  627  of  FIG.  6   . 
     In the example of  FIG.  6   , the cover assembly  624  includes a thicker portion  627  and a thinner portion  625  and the sensing array  670  is generally located in the vicinity of the thicker portion  627 . The thicker portion  627  is at least partially defined by a thicker portion of the cover member  634  and the thinner portion  625  is at least partially defined by a thinner portion of the cover member  634 . The thicker portion  627  also defines a feature  657  that protrudes with respect to the thinner portion  625 . The feature  657  is also referred to generally herein as a protruding region, as a protruding feature, or as a bump. The thicker portion of the cover member  634  at least partially defines the protruding feature  657 . 
     The thinner portion  625  defines an exterior surface  626  (also referred to herein as a base surface). The thicker portion  627  defines an exterior surface  628  (also referred to herein as a raised surface or top surface). As an example, the exterior surface  628  may substantially define a plateau. Such an exterior surface may also be referred to herein as a (raised) plateau surface. The feature  657  protrudes with respect to the exterior surface portion  626 . 
     In the example of  FIG.  6   , the through-holes  667  and  668  extend through the thicker portion  627  of the cover assembly  624 . The size of through-holes  667  and  668  is exaggerated for convenience of illustration. Openings to the holes are located in the exterior surface  628 . In some cases, the exterior surface  628  may have a texture configured to give an optical contrast with the texture of the exterior surface  626 , as previously discussed with respect to  FIG.  1 B . In some cases, the raised surface  628  may have a root mean square height less than that of the surface  626 , and in some cases may be a polished surface. The root mean square height of a polished surface in some cases may be 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. In some cases, the root mean square height of a surface configured to have a texture rougher than a polished surface may be 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 0.25 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 microns. The examples of root mean square heights for different surface textures provided with respect to  FIG.  6    are generally applicable herein. However, in other cases, the exterior surface  628  may have a texture substantially the same as the texture of the surface  626 . The through-holes may be referred to as a set of through-holes and in some cases may define an array of through-holes. Similarly, the openings may be referred to as a set of openings and in some cases may define an array of openings. A module such as a camera module, a sensor module, or an illumination module may be positioned below or within each opening of the set of openings. In addition, at least some of the modules may extend into respective through-holes of the set of through-holes. 
     The electronic device  600  further includes a camera array  675 . The cross-section view of  FIG.  6    shows two optical modules ( 677 ,  678 ) of the camera array  675 . The camera array  675  further includes a support structure  671 . The support structure  671  may be configured to hold various elements of the camera array  675  in place. For example, each of the optical modules  677  and  678  may be mounted to the support structure  671 . In the example of  FIG.  6   , the support structure  671  includes a bracket  672  that has a non-planar profile. The shape of the bracket  672  is not limited to the example of  FIG.  6    and in other examples may have the form of a flat element. The bracket  672  may be coupled to an interior surface of the cover assembly  624 . In the example of  FIG.  6   , the support structure  671  also includes a frame  673  which nests at least partially within the bracket  672  and supports a circuit assembly  674 , which may be mounted on a printed circuit board. However, this example is not limiting and in additional embodiments the frame  673  may be omitted. The support structure  671  and the coupling between the camera array  675  and the interior surface  642  of the cover assembly  624  may be configured to limit bending of the cover member  634  in the vicinity of the protruding feature  657 . 
     The first optical module  677  and the second optical module  678  are respectively aligned with the through-holes  667  and  668 . As shown in  FIG.  6   , the first optical module  677  extends substantially through the through-hole  667  and the second optical module  678  extends substantially through the through-hole  668 . In the example of  FIG.  6   , an end of each of the optical modules  677  and  678  extends beyond (protrudes beyond) the surface  628 . In additional examples, an end of an optical module may be flush or recessed with respect to the surface portion  628 . In some cases, an electronic device may include at least one optical module that is flush with or extends beyond the surface portion  628  and another optical module that is recessed with respect to the surface portion  628 . 
     As previously described with respect to  FIGS.  1 A through  4   , an optical module may comprise a camera module, an illumination module, an optical sensor or the like. Typically, the camera array  675  includes at least one camera module and may include two, three, four, or five camera modules. The camera modules are electrically connected to the circuit assembly  674 . As shown in  FIG.  6   , separate windows  687  and  688  are provided over the through-holes  667  and  668  and the retaining components  686  hold the windows  687  and  688  in place. For example, the retaining component  686  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  644  of the cover assembly  624 . 
       FIG.  6    shows a coating  660  provided along an interior surface  652  of the cover member  634 . In some cases, the coating  660  may provide the cover assembly  624  with a desired color. In additional cases, the coating  660  may function as a masking layer. 
     As shown in  FIG.  6   , the camera array  675  is coupled to the coating  660 . In examples where the coating  660  does not extend under the protruding feature  657 , the camera array  675  may be coupled more directly to the interior surface  652  of the cover member  634 . In some cases, the camera array  675  may be coupled to the interior surface  642  of the cover assembly  624  with an adhesive bond, as may be provided by an adhesive layer. As an additional example, the camera array  675  may be coupled to the interior surface  642  of the cover assembly  624  with a fastener or other form of mechanical attachment. 
     In some cases, the coating  660  comprises a polymer. The coating  660  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  660  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  660  may further comprise optional additives such as one or more extenders, diluents, polymerization initiators, and/or stabilizers. In some embodiments, the polymer has a crosslinked structure. 
     In some cases, the coating  660  may include a color layer (e.g., an ink, dye, paint, etc.) and/or a metal layer. As previously described, the coating  660  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  660  or a portion thereof. In some embodiments, the coating  660  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  660  may be from about 2 microns to about 10 microns. In further embodiments, the coating  660  may comprise a metal layer in addition to one or more color layers. 
     The electronic device further includes a front cover assembly  622  and a cover member  632  which may have similar properties to the cover assemblies and cover members previously discussed with respect to  FIGS.  1 A through  5   , and, for brevity, those details are not repeated here. The electronic device  600  further includes a display  664  and a touch sensor  662  provided below the front cover assembly  622 . The display  664  and the touch sensor  662  may be coupled to the front cover assembly  622 . The display  664  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  662  may be configured to detect or measure a location of a touch along the exterior surface of the front cover assembly  622 . The electronic device may further include a front-facing camera as shown in  FIG.  1 A . 
     Each of the cover assembly  622  and the cover assembly  624  is coupled to an enclosure component  610 , such as with an adhesive, a fastener, or a combination thereof (schematically indicated by coupling elements  692  and  694 ). The enclosure component  610  may be similar to the enclosure component  110  of  FIG.  1 A . The enclosure component  610  at least partially defines an interior cavity  601  of the electronic device  600 . 
       FIG.  7    shows an example cross-sectional view of another sensing array of an electronic device.  FIG.  7    shows a sensing array  770  which may be located at the rear of the electronic device  700  and may be an example cross-sectional view along B-B of  FIG.  1 B . The sensing array  770  includes a camera array  775 . The electronic device  700  includes an enclosure  705  which comprises a front cover assembly  722  and a rear cover assembly  724 . The electronic device also includes an enclosure component  710 . 
     The rear cover assembly  724  includes a first cover member  734  which may extend over a component of a wireless communication system and/or a wireless charging system. The rear cover assembly  724  also includes a second cover member  736  which extends over multiple optical modules of the sensing array. The second cover member  736  defines a window over the optical modules  777  and  778  and may also define a window over additional optical modules of the sensing array  770 . The portion of the rear cover assembly  724  including the second cover member  736  is thicker than the portion including the first cover member  734 . As a result, the second cover member  736  is offset with respect to the first cover member  734 . A coupling ring  785  may couple the cover member  736  to the cover member  734 . The coupling ring  785  may be formed of a metal material or another suitable material. 
     The first cover member  734  may define an opening  765  and an insert  738  may be positioned in this opening. The insert  738  defines through-holes  767  and  768  and the optical modules  777  and  778  extend at least partially into these through-holes. The protruding feature  757  is defined by the insert  738 , the second cover member  736 , and coupling ring  785 . The size of through-holes  767  and  768  is exaggerated for convenience of illustration. The insert  738  may also be coupled to the coupling ring, to the first cover member  734 , or both such as with an adhesive. 
     Similarly to the cover member  634 , the first cover member  734  may be formed from a glass material, may be formed from a glass ceramic material, may include one or more glass portions and one or more glass ceramic portions, or may be formed from a glass ceramic layer in combination with one or more of a glass layer, a ceramic layer, or a polymer layer. In some cases, the cover member  734  includes a glass ceramic material. The optical, electrical, and magnetic properties of the first cover member  734  may be similar to those previously described for the cover member  634 . In addition, the first cover member  734  may have a texture similar to that previously described for the cover member  634 . 
     In some cases, the cover member  736  is substantially transparent and has a lower haze and/or a higher transmission over a visible range than the cover member  734 . In additional cases, the cover member  736  may include translucent or opaque portions. When the cover member  736  defines a window over one or more optical components, the optical properties of the cover member  736  may be determined in part by the wavelength range(s) over which the optical component(s) are configured to operate. For example, the optical component (s) may be configured to operate over a visible wavelength range, a near-IR range, or both. For example, the cover member  736  may have one or more optical properties similar to those described for the cover members  232  and  436 . 
     In some embodiments, the cover member  736  may be formed from a glass material or one or more glass layers in combination with one or more of a glass ceramic layer, a ceramic layer, or a polymer layer. In additional embodiments, the cover member  736  is formed from a glass ceramic material or one or more glass ceramic layers in combination with one or more of a glass layer, a ceramic layer, or a polymer layer. In further embodiments, the cover member  736  is formed from a ceramic material such as sapphire. 
     In some cases, the insert  738  is substantially transparent, translucent, or opaque. In some embodiments, the insert  738  may be formed from a glass material or one or more glass layers in combination with one or more of a glass ceramic layer, a ceramic layer, or a polymer layer. In additional embodiments, the insert  738  is formed from a glass ceramic material or one or more glass ceramic layers in combination with one or more of a glass layer, a ceramic layer, or a polymer layer. In further embodiments, the insert  738  is formed from a ceramic material. 
     In additional embodiments, a unitary cover member formed from a single piece of material (rather than the separate cover members  734  and  736  and insert  738  shown in  FIG.  7   ) may extend over one or more optical modules of the sensing array and over other components of the electronic device. Such a unitary cover member may also be referred to as a monolithic cover member. In some cases, such a cover member may include a first portion having a shape similar to that of the first cover member  734 . For example, the first portion may define a substantially planar region surrounding the sensing array. In addition, such a cover member may include a second portion having a shape similar to that of the second cover member  736 . For example, the second portion may define a substantially planar region extending over the optical module(s) of the sensing array and offset with respect to the first portion. This cover member may also include a third portion extending between the first portion and the second portion. Such a unitary cover member may be formed of a glass ceramic material or may include one or more glass ceramic layers in combination with one or more of a glass layer, a ceramic layer, or a polymer layer as previously described with respect to  FIGS.  1 A and  1 B . 
     In some cases, such a unitary cover member may have optical properties similar to those of the cover member  736  and electrical and magnetic properties similar to those of the cover member  734  across all three portions. In additional cases, this cover member may include different optical properties in the different portions. For example, this cover member may include substantially transparent portions extending over one or more optical modules of the sensing array and may also include one or more translucent or opaque portions, which may be similar to the translucent or opaque portions previously described with respect to  FIGS.  1 A and  1 B . 
     The camera module  775  and the optical modules  777  and  778  may be similar to the camera module  675  and the optical modules  677  and  678 . In addition, the support structure  771 , the bracket  772 , the frame  773 , and the circuit assembly  774  may be similar to the support structure  671 , the bracket  672 , the frame  673 , and the circuit assembly  674 . The front cover assembly  722 , the cover member  732 , the display  764 , the touch sensor  762 , the enclosure component  710 , the coupling elements  792  and  794 , and the interior cavity  701  may be similar to the front cover assembly  622 , the cover member  632 , the display  664 , the touch sensor  662 , the enclosure component  610 , the coupling elements  692  and  694 , and the interior cavity  601 . The portions  725  and  727 , the surfaces  726  and  728 , the protruding feature  757 , the through-holes  767  and  768 , the external surface  744 , and the internal surface  742  of the rear cover member  724  may be similar to the portions  625  and  627 , the surfaces  626  and  628 , the protruding feature  657 , the through-holes  667  and  668 , the external surface  644 , and the internal surface  642  of the rear cover member  624 . The internal surface  752  of the rear cover member  734  and the coating  760  may be similar to the internal surface  652  of the rear cover member  634  and the coating  660 . For brevity, these details are not repeated here. 
       FIG.  8    shows an example cross-sectional view of another sensing array of an electronic device.  FIG.  8    shows a sensing array  870  which may be located at the rear of the electronic device  800  and may be an example cross-sectional view along B-B of  FIG.  1 B . The sensing array  870  includes a camera array  875 . The electronic device  800  includes an enclosure  805  which comprises a front cover assembly  822  and a rear cover assembly  824 . The electronic device also includes an enclosure component  810 . 
     The rear cover assembly  824  includes a first cover member  834  which may extend over a component of a wireless communication system and/or a wireless charging system. The rear cover assembly  824  also includes a second cover member in the form of an insert  838 . A coupling ring  885  couples the first cover member  834  to the insert  838 . In some cases, an adhesive may also be used to couple the first cover member  834  to the insert  838 . The first cover member  834  may define an opening  865  and the insert  838  may be positioned in this opening. The portion of the rear cover assembly  824  including the insert  838  is thicker than the portion including the first cover member  834 . Further, the protruding feature  857  is defined by the insert  838  and the coupling ring  885 . 
     The camera array  875  includes two optical modules ( 877 ,  878 ). The insert  838  defines through-holes  867  and  868  and the optical modules  877  and  878  extend at least partially into these through-holes. The coupling ring  885  may be similar to the coupling ring  785 . The size of through-holes  867  and  868  is exaggerated for convenience of illustration. 
     Similar to the cover members  634  and  734 , the cover member  834  may be formed from a glass material, may be formed from a glass ceramic material, may include one or more glass portions and one or more glass ceramic portions, or may be formed from a glass ceramic layer in combination with one or more of a glass layer, a ceramic layer, or a polymer layer. In some cases, the cover member  834  includes a glass ceramic material. The optical, electrical, and magnetic properties of the cover member  834  may be similar to those previously described for the cover member  634 . 
     In some embodiments, the insert  838  may be formed from a glass material or one or more glass layers in combination with one or more of a glass ceramic layer, a ceramic layer, or a polymer layer. In additional embodiments, the insert  838  is formed from a glass ceramic material or one or more glass ceramic layers in combination with one or more of a glass layer, a ceramic layer, or a polymer layer. The insert  838  may also include one or more other durable materials such metals, ceramics, and the like. 
     In some cases, the insert  838  may be substantially transparent, translucent, or opaque. The insert  838  may have one or more optical properties similar to those of the insert  738  and, for brevity, those details are not repeated here. In a similar fashion as previously described with respect to  FIGS.  1 B and  6   , in some cases, the surface  828  (defined by the insert  838 ) may have a different texture than the surface  826  (defined by the cover member  834 ) while in other cases, the surface  828  may have a texture substantially the same as the texture of the surface  826 . For example, the surface  828  may have a root mean square height less than that of the surface  826  and in some cases may be a polished surface. The examples of root mean square heights for different surface textures provided with respect to  FIG.  6    are applicable to the surfaces  828  and  826  and are not repeated here for brevity. 
     The camera module  875 , the optical modules  877  and  878 , the windows  887  and  888 , and the retaining components  886  may be similar to the camera module  675 , the optical modules  677  and  678 , the windows  687  and  688 , and the retaining components  686 . In addition, the support structure  871 , the bracket  872 , the frame  873 , and the circuit assembly  874  may be similar to the support structure  671 , the bracket  672 , the frame  673 , and the circuit assembly  674 . The front cover assembly  822 , the cover member  832 , the display  864 , the touch sensor  862 , the enclosure component  810 , the coupling elements  892  and  894 , and the interior cavity  801  may be similar to the front cover assembly  622 , the cover member  632 , the display  664 , the touch sensor  662 , the enclosure component  610 , the coupling elements  692  and  694 , and the interior cavity  601 . The portions  825  and  827 , the surfaces  826  and  828 , the protruding feature  857 , the through-holes  867  and  868 , the external surface  844 , and the internal surface  842  of the rear cover assembly  824  may be similar to the portions  625  and  627 , the surfaces  626  and  628 , the protruding feature  657 , the through-holes  667  and  668 , the external surface  644 , and the internal surface  642  of the rear cover member  624 . The internal surface  852  of the rear cover member  834  and the coating  860  may be similar to the internal surface  652  of the rear cover member  634  and the coating  660 . For brevity, these details are not repeated here. 
       FIGS.  9 A and  9 B  show partial cross-sectional views of an electronic device.  FIG.  9 A  may be an example of a partial cross-sectional view along C-C of  FIG.  1 B  and  FIG.  9 B  may be an example of a partial cross-sectional view along A-A of  FIG.  1 A . As shown in  FIGS.  9 A and  9 B , the electronic device  900  includes internal device components  981 ,  982 ,  983 , and  985  positioned within the enclosure  905 . As an example, the device components  981 ,  983 , and  985  may be part of a wireless communication system and the device component  982  may be part of a wireless charging system. Additional device components  999  are indicated schematically with a dashed line and may include one or more of the components described with respect to  FIG.  12   . 
     The cover assembly  922  includes a cover member  932  which extends over the internal device component  981 . In some cases, the cover member  932  may be formed from a glass ceramic material. In additional cases, the cover member  934  may include one or more glass portions and one or more glass ceramic portions or may be formed from a glass ceramic layer in combination with one or more of a glass layer, a ceramic layer, or a polymer layer. The cover member  932  may be substantially transparent, or include transparent, translucent, and/or opaque portions. The cover member  932  may have similar optical properties to the cover member  632  and, for brevity that description is not repeated here. 
     The device component  981  may be part of a wireless communication system and in some cases may be a directional antenna (assembly). By the way of example, the device component  981  may have a primary transmission direction which is substantially perpendicular to the front surface of the electronic device. The device component  981 , as well as the device components  983 , and  985  may be similar to the device components  181 ,  183 , and  185  and may be operated at similar frequency ranges. For example, the device components  981 ,  983 , and  985  may be compatible with a 5G wireless protocol (including millimeter wave and/or 6 GHz communication signals). In some cases, the device components  981 ,  983 , and  985  may be configured to transmit wireless signals at a frequency band between about 25 GHz and 39 GHz. 
     The cover assembly  924  includes a cover member  934  which extends over the internal device components  982  and  983 . In some cases, the cover member  934  may be formed from a glass or a glass ceramic material. In additional cases, the cover member  934  may include one or more glass portions and one or more glass ceramic portions or may be formed from a glass ceramic layer in combination with one or more of a glass layer, a ceramic layer, or a polymer layer. The rear cover member  934  may be substantially transparent, translucent, opaque or include transparent, translucent, and/or opaque portions. The cover member  934  may have similar optical properties to the cover member  634  and, for brevity, that description is not repeated here. 
     When the device component  982  is part of an inductive coupling wireless charging system, the cover member  934  may be formed from a material (or combination of materials) having a magnetic permeability sufficiently low that it does not interfere with transmission of magnetic fields generated by the inductive coupling wireless charging system. For example, the component of an inductive coupling wireless charging system may include a wireless receiver component such as a wireless receiver coil or other feature of the wireless charging system. The cover member  934  may have similar magnetic properties to the cover member  634 . 
     The device component  983  may be part of a wireless communication system and in some cases may be a directional antenna (assembly). By the way of example, the device component  983  may have a primary transmission direction which is substantially perpendicular to the rear surface of the electronic device. The cover member  934  may therefore be configured to provide electrical properties suitable for use over the component of a wireless communication system. For example, the cover member  934  may be a dielectric cover member and may be formed from a material having a dielectric constant and a dissipation factor sufficiently low to allow transmission of RF or IR (e.g., near-IR) signals through the cover member. The cover member  934  may have similar dielectric properties to the cover member  634  and the wireless communication system may be as previously described with respect to  FIGS.  1 A and  1 B . For brevity, these details are not repeated here. 
     As shown in  FIG.  9 B , the enclosure  905  also includes a cover assembly  915 . In some cases, the cover assembly  915  may provide a window for a device component  985 . For example, the cover assembly  915  may define an antenna window for transmitting and receiving wireless signals. For example, the cover assembly  915  may be configured to transmit wireless signals at one or more of the frequencies previously discussed with respect to the device components  181 ,  183 , and  185 . For example, the cover assembly  915  may be configured to transmit wireless signals at a frequency band between about 25 GHz and 39 GHz. 
     The cover assembly  915  may include a cover member  936 . The cover member  936  may be formed from a dielectric material. In some cases, the cover member  936  may be formed from a glass ceramic material, may include one or more glass ceramic portions, or may be formed from a glass ceramic layer in combination with one or more of a glass layer, a ceramic layer, or a polymer layer. In additional cases, the cover member  936  may be formed from a glass material, a ceramic material, a polymeric material, or combinations thereof. The cover member  936  may include one or more glass ceramic portions or may be formed from a glass ceramic layer in combination with one or more of a glass layer, a ceramic layer, or a polymer layer. The cover member  936  may be substantially transparent, translucent, opaque, or include transparent, translucent and/or opaque portions. The cover member  936  may have similar optical properties to the cover member  634  and, for brevity that description is not repeated here. 
     The device component  985  may be part of a wireless communication system and in some cases may be a directional antenna (assembly). By the way of example, the device component  985  may have a primary transmission direction which is substantially perpendicular to the side surface of the electronic device. 
     The enclosure  905  of the electronic device  900  also includes an enclosure component  910 . The enclosure component  910  includes members  912   a  and  912   b . The members  912   a  and  912   b  may be formed of metal or another electrically conductive material. Alternately, the members  912   a  and  912   b  may be formed from any of the materials described for the members  112   a ,  112   b ,  112   c , and  112   d  of  FIGS.  1 A and  1 B . 
       FIG.  10    shows another example electronic device including a sensing array, which is also referred to as a sensing panel. The electronic device  1000  may be a wearable electronic device such as watch and the sensing panel  1070  may be located at the rear of the electronic device. 
     The electronic device  1000  includes a rear cover assembly  1024 . In the example of  FIG.  10   , the rear cover assembly  1024  comprises a cover member  1036  positioned over at least a portion of the sensing panel  1070 . The rear cover assembly also comprises a cover member  1034 . The rear cover assembly  1024  may at least partially define a rear surface  1004  of the wearable electronic device  1000 . For example, the rear surface  1004  of the wearable electronic device may contact the skin of a user when the device is worn. An electrode  1054  may be positioned along the rear surface  1004  and contact the skin of a user wearing the device. The electronic device  1000  further includes an enclosure component  1010  and input devices  1003  and  1007 . The electronic device also typically includes a front cover assembly and a display, as discussed in further detail below. 
     As shown in  FIG.  10   , the electronic device comprises a sensing panel  1070 . The sensing panel  1070  may include one or more sensor assemblies. For example, the one or more sensor assemblies may be one or more health monitoring sensor assemblies or biosensor assemblies, such an electrocardiogram (ECG) sensor, a photoplethysmogram (PPG) sensor, a heart rate sensor, a pulse oximeter or other oxygen sensor, or other bio-sensor. In some cases, a sensor assembly is configured to illuminate the tissue of the user wearing the device and then measure light that is transmitted back to the device. 
     In the example of  FIG.  10   , the sensing panel  1070  includes four optical modules  1082  and four optical modules  1083 . In some examples, the optical modules  1082  are configured to emit a first optical signal and the optical modules  1083  are configured to detect a second optical signal transmitted back to the device. For example, the second optical signal may include light from the first optical signal that is reflected back to the device  1000 , also referred to as a reflection of the first optical signal. The example of  FIG.  10    is not limiting, and the electronic device may include a greater or a lesser number of optical modules. Further, the arrangement of emitter modules and receiver modules is not limited to that shown in  FIG.  10   . 
     The electronic device may include one or more optical modules which emit light, also referred to herein as an emitter module. An emitter module may emit light over at least a portion of the visible spectrum (e.g., green light and/or red light), in which case the optical signal may be a visible (light) signal. Alternately or additionally, the emitter module may emit light over a near-IR wavelength range, in which case the optical signal may be a near-IR (light) signal. 
     In some embodiments, the sensing array includes a biosensor assembly which includes one or more emitter modules and one or more receiver modules. For example, a heart rate biosensor may include an emitter module which produces a visible light signal (e.g., green light) and which produces an infrared light signal. As another example, a pulse oximetry biosensor (e.g., an SpO 2  sensor) may include an emitter module which produces an optical signal over a wavelength range at which the absorption of oxygenated hemoglobin and deoxygenated hemoglobin is different (e.g., red light) and which produces an optical signal over a wavelength range at which the absorption of oxygenated hemoglobin and deoxygenated hemoglobin is similar (e.g., green light or infrared light). The biosensor assembly may include a chassis positioned below the cover assembly  1024  and the emitter module(s) and receiver module(s) may be attached to the chassis. 
     In some examples the cover member  1036  may be positioned over the optical modules  1082  and  1083  (and the cover member  1036  may act as a window for the optical modules  1082  and  1083 ). In other examples, the cover member  1036  may define openings which are positioned over the optical modules  1082  and  1083  and additional cover members may be placed in or over the openings (and act as windows for the for the optical modules  1082  and  1083 ). 
     In some cases, the cover member  1036  may be formed of a glass ceramic material. The glass ceramic cover member may be substantially transparent or may include transparent portions and translucent portions. The cover member  1036  may have optical properties suitable for use over optical components configured to operate over a visible wavelength range and a near-IR wavelength range. These optical properties may be similar to those described for the cover member  734  or for other cover members described herein. In some cases, the cover member  1034  may be translucent or opaque or include translucent or opaque portions. The cover member  1036  may be formed of a glass ceramic material, a ceramic material, a glass material, or combinations thereof as previously described with respect to  FIGS.  1 A and  1 B . 
     As shown in  FIG.  10   , the enclosure  1005  includes an enclosure member  1010  that defines a curved side surface  1006  that extends from the bottom surface to a top surface of the electronic device. In some cases, the rear surface  1004  of the electronic device  1000  may be substantially flat while in other cases the cover member  1036  may define a convex outer contour. A band  1050  may be attached to the housing and configured to secure the wearable electronic device to a user (in  FIG.  10   , the band  1050  is curved to show the rear surface  1004 ). The enclosure  1005  may define a cavity and the enclosure member  1010  may define an opening to the cavity. 
     A display, such as a touch-sensitive display, may be at least partially disposed within the cavity and may have a viewable area. The device may also include a front cover member disposed above the display and including a flat middle portion larger than the viewable area of the display, and a curved edge portion surrounding the flat middle portion and coinciding with the curved side portion along a perimeter of the cavity to form a continuous contoured surface. In some cases, the front cover member may be formed from a glass ceramic material. The front cover member may have similar optical properties to the cover members  132  and  232  (as suitable for use over an optical component configured operate over a visible wavelength range). For brevity, that description is not repeated here. 
     The electronic device  1000  may further include a crown module that is positioned at least partially within an aperture formed within the curved side portion of the housing. The crown module may include an input member  1003  (e.g., a dial) having an outer surface configured to receive a rotary user input. The crown module may be offset with respect to a centerline of the housing between the top portion and the flat bottom portion. The offset may be toward the top portion of the housing. The crown module may include a dial having a portion that is higher than an interface between the cover and the housing. 
       FIGS.  11 A and  11 B  show views of an additional example electronic device including a sensing array.  FIG.  11 B  shows a sensing array  1170  which may be located at the rear of the electronic device  1100 . The sensor array  1170  is associated with a protruding feature  1157  of the enclosure  1105 . 
     The electronic device  1100  includes an enclosure  1105  which comprises a front cover assembly  1122  and a rear cover assembly  1124 . The enclosure  1105  also includes an enclosure component  1110 . In a similar fashion as described for  FIG.  1 B , a thicker portion of the rear cover assembly  1124  defines a protruding feature  1157 . The sensing array  1170  is located at this thicker portion of the rear cover assembly  1124 . The enclosure  1105  defines a front surface  1102 , a rear surface  1104 , and a side surface  1106  of the electronic device  1100 . 
     The sensing array  1170  includes a sensor module  1154  and camera module  1152 . The sensor module  1154  may be an ambient light sensor, a Lidar sensor, or any of the optical sensor modules previously described with respect to  FIG.  1 B . Each of the camera modules  1152  may be configured to operate over a visible wavelength range. The description of camera modules previously provided with respect to  FIGS.  1 A and  1 B  is generally applicable herein, and, for brevity, is not repeated here. The sensing array  1170  also includes another sensor component  1153  such as a microphone, a smaller optical component (e.g., a flash), and the like. 
     The rear cover assembly  1124  comprises a cover member  1134  and a cover member  1136 . The cover member  1134  extends over an internal component  1182  of the electronic device. The cover member  1134  may be configured to allow transmission of electromagnetic signals to and/or from the internal component  1182 . In some cases, the internal component  1182  is part of a wireless communication system. For example, the internal component  1182  may be an antenna configured to radiate an RF signal. The antenna and the wireless communication system may be any of antennas and wireless communication systems previously described with respect to  FIGS.  1 A and  1 B . 
     In some cases, the cover member  1134  may be formed from a glass material, may be formed from a glass ceramic material, may include one or more glass portions and one or more glass ceramic portions, or may be formed from a glass ceramic layer in combination with one or more of a glass layer, a ceramic layer, or a polymer layer. In some cases, the cover member  1134  includes a glass ceramic material. The optical, electrical, and magnetic properties of the cover member  1134  may be similar to those previously described for the cover members  634 ,  734 , or  834  or other cover members described herein. In additional cases, the cover member  1134  may be formed from a metal material and integrated with the enclosure member  1110 . In such cases, an additional RF-transmissive cover member may be provided over the internal component  1182  if desired. 
     In some cases, the second cover member  1136  extends over the sensor module  1154  and camera module  1152  of the sensing array in a similar fashion as previously shown in  FIG.  7   . In other cases, the second cover member  1136  may define through-holes and the sensor module  1154  and camera module  1152  may extend into the through-holes as previously shown in  FIG.  8   . The cover member  1136  at least partially defines the protruding feature  1157 , as previously described with respect to  FIG.  7   . A coupling ring  1185  may couple the cover member  1136  to the cover member  1134 . The cover member  1136  may have a similar composition and optical and electrical/magnetic properties to the cover member  736 . For brevity, these details are not repeated here. In additional embodiments, a monolithic cover member  1134  may define the protruding feature  1157  in a similar fashion as described for  FIG.  6   . 
     The front cover assembly  1122  is positioned over a display  1142  and may provide a substantially transparent window through which the display may be viewed. The front cover assembly  1122  comprises a cover member  1132  which may be formed from or which may include a glass ceramic material. In some cases, the cover member  1132  may have a similar composition and optical properties as described for the cover members  122  and  222  and, for brevity, this description is not repeated here. 
     The enclosure component  1110  comprises multiple members. The members  1112   a ,  1112   b ,  1112   c , and  1112   d  may be formed of metal or another electrically conductive material. Alternately, the members  1112   a ,  1112   b ,  1112   c , and  1112   d  may be formed from any of the materials described for the members  112   a ,  112   b ,  112   c , and  112   d  of  FIGS.  1 A and  1 B . The members  1114  and  1115  may be formed of a polymer or another dielectric material, as previously described for the members  114   a ,  114   b ,  114   c , and  114   d  of  FIGS.  1 A and  1 B . The electronic device further comprises input devices  1137  and  1138 , which may be similar to the input devices  152  and  154  described with respect to  FIGS.  1 A and  1 B . For brevity, that description is not repeated here. 
       FIG.  12    shows a block diagram of a sample electronic device that can incorporate a component comprising a glass ceramic material as described herein. The schematic representation depicted in  FIG.  12    may correspond to components of the devices depicted in  FIGS.  1 A to  11 B  as described above. However,  FIG.  12    may also more generally represent other types of electronic devices including a component comprising a glass ceramic material as described herein. 
     In embodiments, an electronic device  1200  may include sensors  1220  to provide information regarding configuration and/or orientation of the electronic device in order to control the output of the display. For example, a portion of the display  1208  may be turned off, disabled, or put in a low energy state when all or part of the viewable area of the display  1208  is blocked or substantially obscured. As another example, the display  1208  may be adapted to rotate the display of graphical output based on changes in orientation of the device  1200  (e.g., 90 degrees or 180 degrees) in response to the device  1200  being rotated. 
     The electronic device  1200  also includes a processor  1206  operably connected with a computer-readable memory  1202 . The processor  1206  may be operatively connected to the memory  1202  component via an electronic bus or bridge. The processor  1206  may be implemented as one or more computer processors or microcontrollers configured to perform operations in response to computer-readable instructions. The processor  1206  may include a central processing unit (CPU) of the device  1200 . Additionally, and/or alternatively, the processor  1206  may include other electronic circuitry within the device  1200  including application specific integrated chips (ASIC) and other microcontroller devices. The processor  1206  may be configured to perform functionality described in the examples above. 
     The memory  1202  may include a variety of types of non-transitory computer-readable storage media, including, for example, read access memory (RAM), read-only memory (ROM), erasable programmable memory (e.g., EPROM and EEPROM), or flash memory. The memory  1202  is configured to store computer-readable instructions, sensor values, and other persistent software elements. 
     The electronic device  1200  may include control circuitry  1210 . The control circuitry  1210  may be implemented in a single control unit and not necessarily as distinct electrical circuit elements. As used herein, “control unit” will be used synonymously with “control circuitry.” The control circuitry  1210  may receive signals from the processor  1206  or from other elements of the electronic device  1200 . 
     As shown in  FIG.  12   , the electronic device  1200  includes a battery  1214  that is configured to provide electrical power to the components of the electronic device  1200 . The battery  1214  may include one or more power storage cells that are linked together to provide an internal supply of electrical power. The battery  1214  may be operatively coupled to power management circuitry that is configured to provide appropriate voltage and power levels for individual components or groups of components within the electronic device  1200 . The battery  1214 , via power management circuitry, may be configured to receive power from an external source, such as an alternating current power outlet. The battery  1214  may store received power so that the electronic device  1200  may operate without connection to an external power source for an extended period of time, which may range from several hours to several days. 
     In some embodiments, the electronic device  1200  includes one or more input devices  1218 . The input device  1218  is a device that is configured to receive input from a user or the environment. The input device  1218  may include, for example, a push button, a touch-activated button, a capacitive touch sensor, a touch screen (e.g., a touch-sensitive display or a force-sensitive display), a capacitive touch button, dial, crown, or the like. In some embodiments, the input device  1218  may provide a dedicated or primary function, including, for example, a power button, volume buttons, home buttons, scroll wheels, and camera buttons. 
     The device  1200  may also include one or more sensors or sensor modules  1220 , 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  1200  includes a sensor array (also referred to as a sensing array) which includes multiple sensors  1220 . 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 cameras modules may also be associated with the protruding feature. The sensors  1220  may be operably coupled to processing circuitry. In some embodiments, the sensors  1220  may detect deformation and/or changes in configuration of the electronic device and be operably coupled to processing circuitry that controls the display based on the sensor signals. In some implementations, output from the sensors  1220  is used to reconfigure the display output to correspond to an orientation or folded/unfolded configuration or state of the device. Example sensors  1220  for this purpose include accelerometers, gyroscopes, magnetometers, and other similar types of position/orientation sensing devices. In addition, the sensors  1220  may include a microphone, acoustic sensor, light sensor (including ambient light, infrared (IR) light, ultraviolet (UV) light, 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, a pulse oximeter, a biometric sensor (e.g., a fingerprint sensor), or other types of sensing device. 
     In some embodiments, the electronic device  1200  includes one or more output devices  1204  configured to provide output to a user. The output device  1204  may include display  1208  that renders visual information generated by the processor  1206 . The output device  1204  may also include one or more speakers to provide audio output. The output device  1204  may also include one or more haptic devices that are configured to produce a haptic or tactile output along an exterior surface of the device  1200 . 
     The display  1208  may include a liquid-crystal display (LCD), a light-emitting diode (LED) display, an LED-backlit LCD display, an organic light-emitting diode (OLED) display, an active layer organic light-emitting diode (AMOLED) display, an organic electroluminescent (EL) display, an electrophoretic ink display, or the like. If the display  1208  is a liquid-crystal display or an electrophoretic ink display, the display  1208  may also include a backlight component that can be controlled to provide variable levels of display brightness. If the display  1208  is an organic light-emitting diode or an organic electroluminescent-type display, the brightness of the display  1208  may be controlled by modifying the electrical signals that are provided to display elements. In addition, information regarding configuration and/or orientation of the electronic device may be used to control the output of the display as described with respect to input devices  1218 . In some cases, the display is integrated with a touch and/or force sensor in order to detect touches and/or forces applied along an exterior surface of the device  1200 . 
     The electronic device  1200  may also include a communication port  1212  that is configured to transmit and/or receive signals or electrical communication from an external or separate device. The communication port  1212  may be configured to couple to an external device via a cable, adaptor, or other type of electrical connector. In some embodiments, the communication port  1212  may be used to couple the electronic device  1200  to a host computer. 
     The electronic device  1200  may also include at least one accessory  1216 , such as a camera, a flash for the camera, or other such device. The camera may be part of a camera array or sensing array that may be connected to other parts of the electronic device  1200  such as the control circuitry  1210 . 
     As used herein, the terms “about,” “approximately,” “substantially,” “similar,” and the like are used to account for relatively small variations, such as a variation of +/−10%, +/−5%, +/−2%, or +/−1%. In addition, use of the term “about” in reference to the endpoint of a range may signify a variation of +/−10%, +/−5%, +/−2%, or +/−1% of the endpoint value. In addition, disclosure of a range in which at least one endpoint is described as being “about” a specified value includes disclosure of the range in which the endpoint is equal to the specified value. 
     As used herein, the phrase “one or more of” or “at least one of” or” preceding a series of items, with the term “and” or “or” to separate any of the items, modifies the list as a whole, rather than each member of the list. The phrase “one or more of” or “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 “one or more of A, B, and C” or “one or more of A, B, or C” each refer to only A, only B, or only C; any combination of A, B, and C; and/or one or more of each of A, B, and C. 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: 20210812
Publication Date: 20240709
Grant Date: 20240709
Priority Date: 20201012
Inventors: PREST, CHRISTOPHER D.
ROGERS, MATTHEW S.
NGUYEN, Que Anh S.
Assignee: APPLE INC
CPC Classifications: [{"code": "C04B35/119", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1684", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06F1/1686", "inventive": true, "first": false, "tree": "[]"}, {"code": "C04B35/46", "inventive": true, "first": true, "tree": "[]"}, {"code": "C03C10/00", "inventive": true, "first": true, "tree": "[]"}, {"code": "C04B35/119", "inventive": true, "first": false, "tree": "[]"}, {"code": "C04B35/46", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 78086256