Patent Publication Number: US-11050867-B2

Title: Electronic devices with adjustable decoration

Description:
This application is a continuation of U.S. patent application Ser. No. 16/134,846, filed Sep. 18, 2018, which claims the benefit of provisional patent application No. 62/646,677, filed Mar. 22, 2018, which are hereby incorporated by reference herein in their entireties. 
    
    
     FIELD 
     This relates generally to electronic devices, and more particularly, to electronic devices with decoration. 
     BACKGROUND 
     Electronic devices such as cellular telephones include electrical components such as displays, sensors, buttons, and other components. The electrical components in an electronic device allow the device to gather input from a user and the user&#39;s surroundings and allow the device to provide output to the user. 
     Electronic devices such as cellular telephones and other devices also include structures that are primarily decorative, such as ink layers and patterned metal features. These structures, which may sometimes be referred to as decoration, may be used to provide a device with an attractive appearance. In some arrangements, features such as patterned metal or ink layers may be used to form a logo. 
     SUMMARY 
     An electronic device may have a housing in which electrical components such as a display and other components are mounted. In some configurations, the housing may include a transparent member such as a glass layer. The electronic device may be a wearable device having a housing or other support structure that is configured to be worn by a user. 
     Adjustable decoration may be formed on the electronic device. The adjustable decoration may serve as trim for the housing or a component mounted on the housing, may be visible through the transparent member, or may otherwise be incorporated into the electronic device. The adjustable decoration may have an appearance that is electrically adjustable by control circuitry in the electronic device. 
     The control circuitry may measure sensor data using sensors, may gather user input from input-output devices, and may gather other information. When an appropriate event is detected such as an incoming communication, a calendar reminder, user input, activation of an electrical component such as a camera, or other event, the control circuitry can adjust the appearance of the adjustable decoration, thereby helping to notify the user and others of the occurrence of the event. The adjustable decoration can also be adjusted for aesthetic reasons. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative electronic device such as a laptop computer in accordance with an embodiment. 
         FIG. 2  is a perspective view of an illustrative electronic device such as a handheld electronic device in accordance with an embodiment. 
         FIG. 3  is a perspective view of an illustrative electronic device such as a tablet computer, wristwatch, head-mounted device, or other wearable device in accordance with an embodiment. 
         FIG. 4  is a perspective view of an illustrative electronic device such as a computer in accordance with an embodiment. 
         FIG. 5  is a schematic diagram of an illustrative electronic device in accordance with an embodiment. 
         FIG. 6  is a cross-sectional side view of an illustrative electronic device in accordance with an embodiment. 
         FIG. 7  is a cross-sectional side view of layers for adjustable decoration in an electronic device in accordance with an embodiment. 
         FIG. 8  is a cross-sectional side view of a layer of decoration in accordance with an embodiment. 
         FIG. 9  is a cross-sectional side view of a dielectric stack forming a thin-film interference filter structure for a decoration layer in accordance with an embodiment. 
         FIG. 10  is a rear view of an illustrative electronic device with decoration in accordance with an embodiment. 
         FIGS. 11 and 12  are cross-sectional side views of illustrative layers for an electronic device with decoration in accordance with an embodiment. 
         FIG. 13  is a flow chart of illustrative operations involved in operating an electronic device with adjustable decoration in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     An electronic device may include input-output devices such as displays, cameras, sensors, and other components. Decoration may be included in the electronic device such as trim structures around portions of an electronic device housing, trim surrounding a display or camera, or other trim structures, a decorative logo, coatings with desired appearances, or other decorative structures (sometimes referred to as decoration, decorative layers, patterned decorative structures, etc.). For example, a housing wall of a cellular telephone or other device may be provided with decoration. The decoration is not used to display complex content such as still and moving image content displayed on a display, but rather provides the electronic device with a desired appearance and/or brand marking. 
     To enhance the functionality of the electronic device, the decoration in the electronic device may be adjustable. For example, the surface of the electronic device may be provided one or more layers with optical characteristics that are electrically adjustable. By adjusting the electrically adjustable layer(s), the appearance of decoration that is formed from the layers and/or that is overlapped by the layers can be adjusted. 
     With one illustrative configuration, an inner surface of a glass housing wall may be provided with one or more decorative elements with a fixed appearance (e.g., a patterned logo, a blanket coating of a desired appearance, etc.) and may be provided with one or more adjustable layers. An electrically adjustable layer such as a layer with adjustable tint, reflectivity, and/or haze, can overlap the fixed decorative elements. During operation of the electronic device, the appearance of the decoration can be adjusted. Adjustments can be made that serve as a visual notification (e.g., to alert a user or others in the vicinity of the electronic device of the occurrence of an event such as receipt of a message, activation of a camera, etc.). Adjustments can also be made based on user input. For example, a user may supply the electronic device with input specifying a desired color or other appearance attribute. 
     Illustrative electronic devices that may be provided with adjustable decoration are shown in  FIGS. 1, 2, 3, and 4 . 
       FIG. 1  shows how electronic device  10  may have the shape of a laptop computer having upper housing  12 A and lower housing  12 B with components such as keyboard  16  and touchpad  18 . Device  10  may have hinge structures  20  that allow upper housing  12 A to rotate in directions  22  about rotational axis  24  relative to lower housing  12 B. Display  14  may be mounted in upper housing  12 A. Upper housing  12 A, which may sometimes referred to as a display housing or lid, may be placed in a closed position by rotating upper housing  12 A towards lower housing  12 B about rotational axis  24 . 
       FIG. 2  shows how electronic device  10  may be a handheld device such as a cellular telephone, music player, gaming device, navigation unit, or other compact device. In this type of configuration for device  10 , housing  12  may have opposing front and rear surfaces. Display  14  may be mounted on a front face of housing  12 . Display  14  may, if desired, have openings for components such as button  26  or button functions can be implemented using touch sensors, force sensors, and/or other sensors under display  14 . Openings may also be formed in display  14  to accommodate a speaker port (see, e.g., speaker port  28  of  FIG. 2 ). 
     Electronic device  10  may be a tablet computer, a wristwatch device, a wearable device (e.g., a head-mounted device), or other device. For example, device  10  of  FIG. 3  may be a small portable device such as a wristwatch or other wearable device. A strap may be attached to device  10  to allow device  10  to be worn on the hand or head of a user. In some configurations, device  10  may be a head-mounted device (e.g., a helmet, goggles, glasses, etc.). As shown in  FIG. 3 , electronic device  10  may, in some configurations, have a housing (e.g., housing  12 ) with opposing planar front and rear surfaces (e.g., in configurations in which device  10  is a tablet computer). Display  14  may be mounted on the front surface of housing  12 . In some configurations, display  14  may have an opening to accommodate a component such as button  26  (as an example). In head-mounted devices and other wearable devices, housing  12  may be configured to be worn by a user on the user&#39;s head (e.g., housing  12  may be configured to form a head-mounted support structure or other support structure enabling device  10  to be worn by a user). 
       FIG. 4  shows how electronic device  10  may be a computer display or a computer that has been integrated into a computer display. With this type of arrangement, housing  12  for device  10  may be mounted on a support structure such as stand  30  or stand  30  may be omitted (e.g., to mount device  10  on a wall). Display  14  may be mounted on a front face of housing  12 . 
     The illustrative configurations for device  10  that are shown in  FIGS. 1, 2, 3, and 4  are merely illustrative. In general, electronic device  10  may be a laptop computer, a computer monitor containing an embedded computer, a tablet computer, a cellular telephone, a media player, or other handheld or portable electronic device, a smaller device such as a wristwatch device, a pendant device, a headphone or earpiece device, or other wearable or miniature device (e.g., glasses, goggles, other head-mounted equipment, etc.), a television, a computer display that does not contain an embedded computer, a gaming device, a navigation device, an embedded system such as a system in which electronic equipment with a display is mounted in a kiosk or automobile, equipment that implements the functionality of two or more of these devices, or other electronic equipment. 
     Housing  12  of device  10 , which is sometimes referred to as a case, may be formed of materials such as plastic, glass, ceramics, carbon-fiber composites and other fiber-based composites, metal (e.g., machined aluminum, stainless steel, or other metals), other materials, or a combination of these materials. Device  10  may be formed using a unibody construction in which most or all of housing  12  is formed from a single structural element (e.g., a piece of machined metal or a piece of molded plastic) or may be formed from multiple housing structures (e.g., outer housing structures that have been mounted to internal frame elements or other internal housing structures). 
     Display  14  may be a touch sensitive display that includes a touch sensor or may be insensitive to touch. Touch sensors for display  14  may be formed from an array of capacitive touch sensor electrodes, a resistive touch array, touch sensor structures based on acoustic touch, optical touch, or force-based touch technologies, or other suitable touch sensor components. 
     Display  14  for device  10  includes display pixels formed from liquid crystal display (LCD) components, light-emitting diodes (e.g., organic light-emitting diodes or light-emitting diodes formed from individual crystalline semiconductor dies), electrophoretic display components, or other suitable image pixel structures. 
     A display cover layer may cover the surface of display  14  or a display layer such as a color filter layer or other portion of a display may be used as the outermost (or nearly outermost) layer in display  14 . The outermost display layer may be formed from a transparent glass sheet, a clear plastic layer, or other transparent member. 
     A schematic diagram of device  10  showing illustrative components that may be used in device  10  is shown in  FIG. 5 . As shown in  FIG. 5 , electronic device  10  may have control circuitry  32 . Control circuitry  32  may include storage and processing circuitry for supporting the operation of device  10 . The storage and processing circuitry may include storage such as hard disk drive storage, nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory configured to form a solid state drive), volatile memory (e.g., static or dynamic random-access-memory), etc. Processing circuitry in control circuitry  32  may be used to control the operation of device  10 . The processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, baseband processors, power management units, audio chips, application specific integrated circuits, etc. Control circuitry  32  may include radio-frequency transceiver circuitry, antennas, and/or other communications circuitry for forming communications links between device  10  and external equipment (e.g., wired links, wireless links such as cellular telephone lines, wireless local area network links, Bluetooth® links, etc.). Satellite navigation system receiver circuitry in control circuitry  32  may be used to gather information on the geographic location of device  10 . Location information can also be gathered using information on wireless local area network connections, cellular telephone information (e.g., information on the identify of cell towers communicating with device  10 ), etc. 
     Input-output circuitry in device  10  such as input-output devices  34  may be used to allow data to be supplied to device  10  and to allow data to be provided from device  10  to external devices. Input-output devices  34  may include buttons, joysticks, scrolling wheels, touch pads, key pads, keyboards, microphones, speakers, tone generators, haptic output devices (e.g., vibrators), cameras, light-emitting diodes and other status indicators, data ports, etc. A user can control the operation of device  10  by supplying commands through input-output devices  34  and may receive status information and other output from device  10  using the output resources of input-output devices  34 . 
     Input-output devices  34  may include one or more displays such as display  14 . Display  14  may be a touch screen display that includes a touch sensor for gathering touch input from a user or display  14  may be insensitive to touch. A touch sensor for display  14  may be based on an array of capacitive touch sensor electrodes, acoustic touch sensor structures, resistive touch components, force-based touch sensor structures, a light-based touch sensor, or other suitable touch sensor arrangements. 
     Input-output devices  34  may also include sensors  38 . Sensors  38  may include a capacitive sensor, a light-based proximity sensor, a magnetic sensor, an accelerometer, a force sensor, a touch sensor, a temperature sensor, a pressure sensor, a compass, a microphone, a color ambient light sensor, depth sensors, and other sensors. Image sensors such as camera  36  may be used to capture images. For example, cameras such as camera  36  may be mounted on a front face of a tablet computer, cellular telephone, or watch, may be mounted above display  14  in a laptop or desktop computer, or may otherwise be mounted in housing  12 . If desired, cameras such as camera  36  may be mounted on a rear housing wall (e.g., on the rear face of a cellular telephone, tablet, etc.). In head-mounted devices, cameras such as camera  36  may be mounted in outwardly facing locations on a housing (e.g., to capture real-world images of a user&#39;s surroundings including people in the vicinity of the user). 
     Adjustable decoration  40  may include one or more adjustable components such as one or more electrically adjustable layers that are each configured to modify one or more optical characteristics of decoration  40 . These optical characteristics may include, for example, tint (e.g., opacity and/or color), reflectivity, transmission, absorption, and haze. In some arrangements, adjustable decoration  40  may include fixed decorative elements (e.g., patterned layer(s) of metal or other materials that form trim, logos, text, and/or other patterns). Configurations in which adjustable layer(s) and layer(s) of fixed appearance are combined to form adjustable decoration  40  may also be used. 
     In some arrangements, adjustable decoration  40  is formed on a front face of device  10  (e.g., on the side of device  10  containing display  14 ). In other arrangements, adjustable decoration  40  is formed on other device locations. For example, adjustable decoration  40  may be formed on curved or planar sidewalls in device  10  (e.g., housing walls that extend between a rear housing wall and the front of device  10 ). Adjustable decoration  40  may also be formed on some or all of a rear housing wall in device  10 . Device  10  may, as an example, have a rear housing wall that is formed from a glass layer or other transparent member. Adjustable decoration  40  may be formed on the inner (interior) surface of the glass layer so as to be visible from the exterior of device  10 . Arrangements may also be used in which adjustable decoration is mounted under a display cover layer on a front face of device  10  (e.g., in a peripheral portion of the display cover layer adjacent to display  14 ). Illustrative scenarios in which adjustable decoration  40  is formed under a transparent member such as a rear housing glass layer may sometimes be described herein as an example. Other arrangements for incorporating adjustable decoration  40  into device  10  may be used, if desired. 
     A cross-sectional side view of a portion of electronic device  10  is shown in  FIG. 6 . In the illustrative configuration of  FIG. 6 , device  10  has a front side (front face) on which display  14  is formed. A user such as viewer  60  who is viewing device  10  in direction  62  may view images displayed on pixels  44  of display  14 . Pixels  44  may be arranged in an array under display cover layer  42  (e.g., a layer of clear glass or polymer). Device  10  also has an opposing rear side (rear face) on which adjustable decoration  40  is formed. Electrical components  50  (see, e.g., control circuitry  32  and/or input-output devices  34  of  FIG. 1 ) may be mounted on one or more substrates such as printed circuit  48  in interior  46  of device  10 . 
     Decoration  40  may have an adjustable appearance to a user such as viewer  64  who is viewing the rear of device  10  in direction  66 . In the example of  FIG. 6 , a rear-facing camera such as camera  36  has been mounted in the housing of device  10 . In some configurations, adjustable decoration  40  and camera  36  may both be visible to viewer  64 . For example, camera  36  and decoration  40  may both face outwardly from device interior  46  (e.g., in a rearward direction in the illustrative configuration of  FIG. 6 ). 
     In some configurations, adjustable decoration  40  has a uniform appearance. In other configurations, different portions of adjustable decoration  40  have different respective appearances. As shown in  FIG. 6 , one or more layers of material that make up adjustable decoration  40  may be patterned to from respective portions such as first portion  58 , second portion  54 , and third portion  56 , which can each have the same visual appearance and/or which can each have a different respective visual appearance to a user. 
     In some configurations, adjustable decoration  40  has a three-dimensional shape (e.g., the shape of a ridge or other protrusion, the shape of a groove or other recess, a pyramidal shape, a conical shape, a shape with a box-shaped protrusion or recess, and/or other three-dimensional shape). Illustrative arrangements in which adjustable decoration  40  has the form of a thin layer (e.g., a coating, etc.) are sometimes described herein as an example. 
     As shown in  FIG. 7 , adjustable decoration  40  may have one or more layers  40 ′ (sometimes referred to as sublayers). Layers  40 ′ may include fixed layers such as fixed patterned metal layers, fixed patterned thin-film interference filters formed from dielectric stacks, fixed patterned polymer layers (e.g., polymer with diffusing embedded particles, a polymer coating and/or other polymer with or without colorant such as dye and/or pigment, laminated polymer films, etc.), fixed layers of fabric, textured films, frosted glass, etc. Layers  40 ′ may also include one or more adjustable optical layers. The adjustable layer(s) may be used in adjusting optical characteristics for adjustable decoration  40  and may include components such as an adjustable tint layer, an adjustable mirror layer, an adjustable haze layer, etc. 
     An adjustable tint layer (sometimes referred to as a light modulator layer or adjustable color layer) may be formed form a light modulator component such as an electrochromic device, guest-host liquid crystal device, a suspended particle device, or other suitable electrically adjustable tint layer. Light absorption and/or color (in transmission and/or in reflection) can be adjusted using the adjustable tint layer. 
     An electrochromic device may have a pair of transparent electrodes. An electrolyte such as LiNiOP (e.g., a gel electrolyte) may be interposed between electrochromic coatings on the electrodes. The electrochromic coatings may be, for example, a Li x NiO coating on a first of the electrodes and a WO 3  coating on a second of the electrodes. The electrodes may be used to apply a current to the electrochromic coatings to either darken (color) or lighten (discolor) electrochromic layer. Electrochromic devices may exhibit low haze (e.g., less than 5%) and may maintain their current state in the event of a failure. If desired, a tint layer for adjustable decoration  40  may be implemented using a solid state electrochromic device in which solid organic or inorganic material is used to form the electrochromic electrolyte. 
     A guest-host liquid crystal device may include a light-absorbing dye “guest” in a liquid crystal “host” layer. These materials may form a layer that is sandwiched between a pair of transparent electrodes. When an electric field is applied to the guest-host layer, the liquid crystals rotate, thereby rotating the guest dye into an orientation that enhances light absorption. When the electric field is removed, the guest dye molecules are no longer held in the high-absorption orientation so that layer becomes transparent. The guest-host layer may vary between transparent and opaque. Partially transparent states may also be exhibited (e.g., at intermediate electric field values). In some states (e.g., non-transparent states), the guest-host layer may exhibit a color cast (e.g., a color associated with the guest dye). 
     Layers  40 ′ may also include an adjustable tint layer implemented using a suspended particle device. A suspended particle device contains a layer of nanoparticles suspended in a liquid that is sandwiched between substrate layers with transparent conductive electrodes. In the absence of an applied electric field, the nanoparticles are randomly oriented and absorb light (i.e., the tint of the adjustable tint layer is dark). When an electric field is applied, the nanoparticles align and allow light to pass (i.e., the tint of the layer is clear). In addition to allowing an adjustable tint to be obtained, suspended particle devices are characterized by an associated adjustable haze (e.g., a 6% haze when the suspended particle device is off and is exhibiting a low amount of light absorption and a 50% haze when the suspended particle device is on and is exhibiting a high amount of light absorption). In this way, a suspended particle device may serve both as an adjustable tint layer and as an adjustable haze layer. 
     In some arrangements, layers  40 ′ may include an adjustable reflectivity layer. An adjustable reflectivity layer for adjustable decoration  40  may be formed from an adjustable reflectivity component such as a cholesteric liquid crystal layer. A cholesteric liquid crystal device may exhibit a mirror reflectivity that is adjustable. When used in adjustable decoration  40 , the cholesteric liquid crystal device may be characterized by an “on” state and an “off” state. In the “on” state (e.g., when control circuitry  32  applies a voltage to the cholesteric liquid crystal device), the cholesteric liquid crystal device may be transparent. The transmission of the cholesteric liquid crystal device may be adjusted by adjusting the applied voltage (i.e., a cholesteric liquid crystal layer may serve both as an adjustable reflectivity layer and as an adjustable tint layer). In the “off” state, the cholesteric liquid crystal device may act as a partial mirror and may reflect more than 50% of incident light, more than 70% of incident light, less than 99% of incident light, or other suitable amount of incident light. 
     Cholesteric liquid crystal layers may exhibit relatively fast switching speeds, low haze (e.g., haze values of less than 5%), and good reflectivity (e.g., when “off”). If desired, adjustable reflectivity layers may be implemented using other types of adjustable mirror components. For example, an adjustable reflectivity component for adjustable decoration  40  may be formed from a solid-state switching mirror component based on a switchable metal hydride film (e.g., adjustable decoration  40  may include an adjustable magnesium hydride mirror layer). 
     If desired, haze may be adjusted using an adjustable haze layer in layers  40 ′. An adjustable haze layer may be implemented using a polymer-dispersed liquid crystal device. In this type of device, a polymer layer having voids filled with liquid crystal material may be sandwiched between conductive transparent electrodes on respective first and second transparent substrates. When no electric field is applied to the electrodes, the liquid crystals in the voids are randomly oriented and exhibit an index-of-refraction difference with the surrounding polymer layer. This causes the liquid crystal material of the voids to produce a relatively large amount of haze that scatters light that is passing through the polymer layer. When electric field is applied to the electrodes by control circuitry  32 , the liquid crystals of the liquid crystal material in the voids becomes aligned so that the liquid crystal material in the voids exhibits an index of refraction that matches the surrounding polymer. In this configuration, the adjustable haze layer exhibits low haze and high transparency. Intermediate haze levels may be achieved by applying an electric field at an intermediate level. 
     In addition to incorporating one or more of these adjustable optical layers in layers  40 ′ of adjustable decoration  40 , one or more fixed optical layers  40 ′ may be incorporated in adjustable decoration  40 . Layers  40 ′ may, for example, be implemented using fixed reflectivity layers (e.g., thin reflective metal coatings, thin reflective dielectric stack coatings, etc.), fixed tint (e.g., glass or polymer that has been darkened by incorporation of light-absorbing particles, dye, metal coating material, etc.), and/or fixed haze (e.g., by incorporating a textured polymer or glass layer, a hazy layer formed from microbubbles or light-scattering particles in a glass or plastic material, etc.). In general, any type of adjustable layer that exhibits an adjustable appearance can be incorporated into decoration  40 . The use of adjustable layers in providing adjustable decoration with adjustable optical characteristics (e.g., adjustable appearance characteristics) using layer(s) with adjustable tint, haze, and/or reflectivity is illustrative. 
     An example of structure that may be used as a fixed decoration layer is shown in  FIG. 8 . Layer  68  of  FIG. 8  may be a solid layer of metal, polymer (e.g., polymer with pigment, dye, and/or other colorant and/or clear polymer), ceramic, glass, textured material or other hazy material (e.g., a polymer layer with embedded inorganic particles of differing refractive index, embedded gas bubbles, and/or other light-scattering particles), and/or other solid layer. 
     As another example, consider the dielectric stack of layer  70  of  FIG. 9 . Layer  70  may be formed from multiple dielectric layers  72 . Layers  72  may be, for example, thin-film layers each having a thickness of less than 3 microns, less than 1.5 microns, less than 0.5 microns, or other small thickness. The refractive index values of layers  72  may alternate or have other suitable arrangements. The thicknesses, materials, and refractive indices of layers  72  may be selected to form a thin-film interference filter from layer  70  with desired optical attributes (desired reflectivity, light absorption, and light transmission as a function of wavelength). Using this type of thin-film interference filter structure, layer  70  can be provided with a desired appearance. 
     Layers such as layer  68  and/or layer  70  may be deposited as blanket films (e.g., globally throughout adjustable decoration  40 ) and/or may be patterned (e.g., localized so that these layers appear only in selected areas within adjustable decoration  40 ). Patterns of layers may form logos, decorative symbols, text, trim, and/or other decoration. In forming adjustable decoration  40 , one or more patterned layers and/or blanket layers such as layers  68  and/or layer  70  may be used in combination with one or more adjustable optical layers. 
     A top view of illustrative adjustable decoration for device  10  is shown in  FIG. 10 . In the example of  FIG. 10 , portion  40 G of adjustable decoration  40  has a first appearance (e.g., a first reflectivity, color, and/or haze), trim portions  40 T have a second appearance (e.g., a second reflectivity, color, and/or haze), and logo  40 L has a third appearance (e.g., a third reflectivity, color, and/or haze). The relative appearances of each of these portions of adjustable decoration  40  can be individually varied with respect to each other and/or global appearance adjustments can be made to two or three of these portions using adjustable layer(s) that overlap (above and/or below) the fixed appearance layers. 
     Illustrative configurations for adjustable decoration  40  in device  10  are shown in  FIGS. 11 and 12 . In the examples of  FIGS. 11 and 12 , viewer (user)  64  is viewing device  10  in direction  66  through layer  74 . Layer  74  may be, for example, a clear rear housing wall, a transparent housing wall on another portion of device  10 , or other transparent structure in device  10  (e.g., a clear layer of polymer, glass, ceramic, a clear crystalline material such as sapphire, etc.). If desired, adjustable decoration  40  of  FIGS. 11 and 12  may be formed in other portions of device  10 . The configurations of  FIG. 11  and  FIG. 12  are presented as examples. 
     In the illustrative arrangement of  FIG. 11 , adjustable decoration  40  includes an adjustable layer such as adjustable layer  76  interposed between decoration layer  78  and the interior surface of transparent layer  74 . Layers such as layers  76  and  78  may be laminated onto the inner surface of layer  74  using heat and/or pressure and/or may be attached with intervening layers of adhesive. 
     Layer  78  may be a layer of fixed decoration. For example, layer  78  may have one or more layers of patterned structures such as patterned portions of layer  68  of  FIG. 8  and/or patterned portions of layer  70  of  FIG. 9  in a pattern that forms a logo, trim, text, and/or other decorative elements. As an example, a metal logo or a thin-film interference filter mirror in the shape of a logo may be formed in layer  78 . The interior portion of layer  78  (e.g., the portion facing the interior of device  10 ) may be formed from a polymer layer (e.g., an ink or paint containing colorant in a polymer) that overlaps the logo and serves as a solid background. The logo may, as an example, have a shinny reflective appearance and the polymer layer may have a dark appearance that allows the polymer layer to serve as a global background layer behind the shiny logo (e.g., the logo may be interposed between layer  76  and the dark polymer layer of layer  78 ). In other configurations, patterned metal, patterned polymer (e.g., polymer with colorant), textured layers of metal, polymer, glass, or other material, and/or thin-film interference filters forming reflective mirrors, colored reflective layers (e.g., layers tinted blue or red by virtue of a non-uniform visible light reflection spectrum), and/or other structures in layer  78  may be used to form non-adjustable decoration patterns in layer  78 . 
     Layer  76  of  FIG. 11  is interposed between layer  78  and layer  74  and therefore adjusts the appearance of layer  78  to viewer  64  as viewer  64  is viewing device  10  in direction  66 . Layer  76  may be any suitable adjustable optical layer (e.g., an adjustable tint layer, adjustable mirror layer, adjustable haze layer, and/or a layer that adjusts other optical attributes and/or combinations of any two or more of these attributes). As an example, consider a scenario in which adjustable layer  76  is an adjustable tint layer that exhibits an electrical adjustable opacity ranging from black to clear. When placed in its clear state, layer  76  allows viewer  64  to view the pattern formed by layer  78  (e.g., a shiny logo). When placed in its non-transparent state(s), layer  76  partially or completely obscures layer  78  from view (e.g., the logo may be partially or completely blocked). The color of a logo or other pattern can also be adjusted in this way. As another example, consider a scenario in which layer  76  is an adjustable haze layer. In its low haze state, layer  76  may be sufficiently clear to allow viewer  64  to view layer  78 . In a higher haze state, layer  76  may be sufficiently hazy to partly or completely obscure layer  78 . In a scenario in which layer  76  is an adjustable mirror, layer  76  can be placed in a low reflectivity state or a high reflectivity state, thereby altering how much (if any) of layer  78  is visible and how much ambient light is reflected to viewer  64 . 
     If desired, adjustable layer  76  may be interposed between fixed decoration layers  78 - 1  and  78 - 2 , as shown in  FIG. 12 . Layers  78 - 1  and  78 - 2  may be, for example, layers with metal, polymer (e.g., colored polymer), dielectric stacks forming thin-film interference filter structures (mirrors, colored filters, antireflection coatings, etc.), and/or textured layers (e.g., layers with fixed haze). As with layer  78  of  FIG. 11 , different regions of layers  78 - 1  and/or  78 - 2  may be patterned differently to form logos, text, trim, and/or other patterns of decoration. As shown in  FIG. 12 , for example, layer  78 - 1  may have an optional opening in region  82  with a desired pattern. If, as an example, layer  78 - 2  is a white background layer and layer  78 - 1  is a black foreground layer, opening  82  may have the shape of a logo, so that viewer  64  views a white logo on a black background. Layer  78 - 2  may also include patterned regions such as region  80 . For example, layer  78 - 1  may be a partially transparent red layer and layer  78 - 2  may be a black layer with a metal logo shape in region  80 . In this scenario, a reflective red logo will appear in region  80  surrounded by a reddish dark background. 
     When it is desired to adjust the appearance of adjustable decoration  40  of  FIG. 12 , control circuitry  32  may electrically adjust the optical characteristics of layer  76 , which is interposed between layer  78 - 1  and  78 - 2 , As an example, consider a scenario in which layer  78 - 1  has a color gradient (e.g., a laterally varying color cast) and in which layer  78 - 2  has a black polymer backing layer with a foreground metal logo (e.g., a metal logo formed between the black polymer layer and layer  76 . In a first illustrative embodiment, layer  76  is an adjustable tint layer that varies between an opaque white color (in which case the logo is blocked and the rear of device  10  has a color gradient determined by the appearance of layer  78 - 1  and a transparent state (in which case the logo is visible and has a color gradient determined by the appearance of layer  78 - 1 ), In a second illustrative embodiment, layer  76  is an adjustable haze layer. In its low haze state, layer  76  may be sufficiently clear to allow viewer  64  to view layer  78 - 2 . When viewing layer  78 - 2 , layer  78 - 2  is viewed through layer  74  (e.g., a transparent housing layer) and through layer  78 - 1  (which may impart a tint, gradient, haze pattern, and/or other characteristics to the appearance of layer  78 - 2 ). In its higher haze state, layer  76  may be sufficiently hazy to partly or completely obscure layer  78 - 2  while allowing the hazy surface of layer  76  to be viewed through layer  78 - 1 . In a third illustrative embodiment, layer  76  is a layer with an adjustable mirror reflectivity. When layer  76  is an adjustable mirror, layer  76  can be placed in a low reflectivity state or a high reflectivity state, thereby altering how much (if any) of layer  78 - 2  is visible through layer  78 - 1  and layer  76  and adjusting the appearance of decoration  40 . 
     Adjustable decoration  40  can be adjusted slowly (e.g., with smooth variations over time periods of 1-10 s, at least 2 s, less than 100 s, or other suitable adjustment time periods) and/or may be adjusted rapidly (e.g., flashing on and/off or otherwise abruptly changing appearance over a time period of 0.1-0.3 s, at least 0.01 s, less than 0.2 s, or other suitable time period). The appearance of decoration  40  may be changed intermittently (e.g., once per day or week as a user desires to alter the appearance of device  10 ) and/or can be adjusted more frequently, continuously, in response to satisfaction of suitable adjustment criteria, etc. For example, control circuitry  32  can monitor for incoming cellular telephone calls, text messages, email messages, or other communications and can adjust the appearance of adjustable decoration  40  in response (e.g., a logo, the background of a logo, and/or a global layer covering a logo can be changed in appearance and/or can flash repeatedly between first and second appearance states to indicate that an incoming telephone call or message has been received). As another example, control circuitry  32  can adjust the appearance of adjustable decoration  40  in response to detection of an event such as a reminder associated with a calendar entry, expiration of a timer, or other time-based and/or date-based appearance adjustment criteria. For example, when a calendar reminder occurs or when a timer expires, adjustable decoration  40  can flash, change color, change haze, change opacity, and/or otherwise be adjusted in appearance. 
     A flow chart of illustrative operations involved in using a device such as device  10  with adjustable decoration  40  is shown in  FIG. 13 . During the operations of block  90 , control circuitry  32  may use input-output devices  34  to monitor for the occurrence of user input from the user of device  10 , for the occurrence of particular sensor readings (e.g., measurements of light, temperature, magnetism, sound, etc. to monitor for the occurrence of a particular geographic location (e.g., a location determined by satellite navigation system receiver circuitry in control circuitry  32 ), to monitor for the occurrence of other events (particular times and/or dates, etc.), to monitor for the receipt of a telephone call, message, or other communications, to monitor for the proximity of a peer device or accessory (as indicated, for example, by the formation of a wireless link that pairs device  10  to external equipment), to monitor for the presence of particular users, to monitor for the activation of particular functions within device  10  (e.g., to monitor for activation of a camera application that allows camera  36  to capture still and/or moving images), to monitor for the activation of operation system features (e.g., voice recognition, facial scanning, etc.), and/or to monitor for the occurrence of other events. 
     Events that may warrant adjustment of decoration  40  can include events measured using sensors  38  and/or other circuitry in device  10  (e.g., input-output devices  34 ), user input, communications, events measured by detecting the operating state of components in device  10  and/or the operating state of a camera application, voice recognition application, sound recording application, or other application and/or operating system software component, and/or other events. If no events warranting adjustment of adjustable decoration  40  are detected, processing can continue during the operations of block  90  (e.g., the circuitry of device  10  can continue to monitor for event occurrence). In response to detection of an event warranting adjustment of adjustable decoration  40 , device  10  (e.g., control circuitry  32 ) may adjust the appearance of adjustable decoration  40  during the operations of block  92 . 
     As an example, in response to detection that camera  36  (e.g., a camera facing people in the vicinity of the user) is active, the appearance of adjustable decoration  40  can be adjusted to alert these people that the camera is active (e.g., that the camera is capturing image data including images of the people). As another example, if an incoming call or message is detected or if a calendar reminder is triggered or a timer expires, the appearance of adjustable decoration  40  can be adjusted (e.g., by flashing, changing once or twice, etc.) to alert the user of the presence of incoming communications or other event. The appearance of decoration  40  can also be adjusted by a user for aesthetic reasons (e.g., to coordinate the appearance of decoration  40  with a user&#39;s clothing, the appearance of a removable case on device  10 , the housing of device  10 , etc.). In some configurations, power consumption can be reduced by using adjustable decoration  40  to provide a user with alerts and other information in place of more power intensive adjustable components in device  10  (e.g., in place of display  14 ). For example, the color of the rear of device  10  can be changed relatively infrequently and/or can remain changed persistently (e.g., until cleared by a user) to remind a user that a message has been received. This appearance adjustment process may consume significantly less power than if device  10  were to power display  14  continuously to display the same type of reminder (as an example). Providing a user with notifications and other information via changes to the appearance of decoration  40  may also be less obtrusive than other forms of notification. A backlight can be provided behind some or all of decoration  40  and used in adjusting the appearance of decoration  40  and/or backlight components can be omitted (e.g., to help conserve power). 
     The foregoing is merely illustrative and various modifications can be made by those skilled in the art without departing from the scope and spirit of the described embodiments. The foregoing embodiments may be implemented individually or in any combination.