PATENT DOCUMENT

Publication Number: US-11696397-B2
Application Number: US-201815967383-A
Country: US
Kind Code: B2

Title: Patterned bonded glass layers in electronic devices

Abstract:
An electronic device may include electrical components and other components mounted within an interior of a housing. The device may have a display on a front face of the device and may have a glass layer that forms a housing wall on a rear face of the device. The glass housing wall may be provided with regions having different appearances. The regions may be textured, may have coatings such as thin-film interference filter coatings formed from stacks of dielectric material having alternating indices of refraction, may have metal coating layers, and/or may have ink coating layers. Textured surfaces, cavities, coatings, and other decoration may be embedded in glass structures that are joined with chemical bonds at diffusion-bonding interfaces.

Claims:
What is claimed is: 
     
       1. An electronic device having opposing front and rear faces, comprising:
 a display on the front face; and 
 a glass housing wall on the rear face, wherein the glass housing wall is formed from a first layer of glass and a second layer of glass that are joined with chemical bonds at a diffusion-bonding interface, the glass housing wall has first and second regions of first and second different respective appearances, the glass housing wall comprises a coating layer that is embedded between the first and second layers of glass, the coating layer overlaps the first region and does not overlap the second region, and the first layer of glass has a textured glass surface in the first region and a smooth glass surface in the second region. 
 
     
     
       2. The electronic device defined in  claim 1  wherein the coating layer comprises inorganic dielectric. 
     
     
       3. The electronic device defined in  claim 1  wherein the coating layer comprises a thin-film interference filter formed from a stack of inorganic dielectric layers. 
     
     
       4. The electronic device defined in  claim 1  wherein the coating layer of the first region is configured to form a logo. 
     
     
       5. The electronic device defined in  claim 1  further comprising a polymer layer on the glass housing wall that overlaps the first and second regions. 
     
     
       6. The electronic device defined in  claim 5  wherein the polymer layer is opaque. 
     
     
       7. The electronic device defined in  claim 1  wherein the textured glass surface overlaps the first region and does not overlap the second region. 
     
     
       8. An electronic device having opposing front and rear faces, comprising:
 a display on the front face; and 
 a glass housing wall on the rear face that has an embedded cavity, wherein the glass housing wall is formed from glass portions that are joined with chemical bonds at a diffusion-bonding interface that extends around an entire perimeter of the embedded cavity, the glass portions comprise first and second glass layers, the first glass layer has a textured glass surface formed from protruding surface structures, and the textured glass surface is interposed between the first and second glass layers. 
 
     
     
       9. The electronic device defined in  claim 8  wherein the glass housing wall has first and second regions of first and second different respective appearances and wherein the first region overlaps the embedded cavity. 
     
     
       10. The electronic device defined in  claim 9  wherein the glass portions comprise a third glass layer, wherein the second glass layer is interposed between the first and third glass layers and has an opening that forms the embedded cavity, wherein the first and second glass layers are joined with chemical bonds at a first diffusion-bonding interface, and wherein the second and third glass layers are joined with chemical bonds at a second diffusion-bonding interface. 
     
     
       11. The electronic device defined in  claim 10  further comprising a coating layer in the embedded cavity. 
     
     
       12. The electronic device defined in  claim 11  wherein the coating layer comprises a dielectric stack of inorganic dielectric layers. 
     
     
       13. The electronic device defined in  claim 11  wherein the coating layer comprises metal. 
     
     
       14. The electronic device defined in  claim 11  wherein the coating layer is configured to form a logo. 
     
     
       15. An electronic device, comprising:
 a housing that includes a glass housing wall with embedded decoration, wherein the glass housing wall is formed from glass structures that are joined with chemical bonds at a diffusion-bonding interface, the glass structures comprise first and second glass layers, the first glass layer has a polished surface at the diffusion-bonding interface and a textured glass surface that forms the embedded decoration, and the textured glass surface is formed from protruding surface structures and is interposed between the first and second glass layers; and 
 electrical components surrounded by the housing. 
 
     
     
       16. The electronic device defined in  claim 15  wherein the glass housing wall has first and second regions of first and second different respective appearances and wherein the first region overlaps the embedded decoration. 
     
     
       17. The electronic device defined in  claim 15  wherein the electronic device has opposing front and rear faces, wherein the glass housing wall is on the rear face, and wherein the electronic device further comprises a display on the front face.

Description:
This application claims the benefit of provisional patent application No. 62/539,454, filed Jul. 31, 2017, which is hereby incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     This relates generally to electronic devices, and, more particularly, to forming visually distinguishable regions in glass structures in electronic devices. 
     Electronic devices such as cellular telephones, computers, watches, and other devices may contain glass structures. For example, electronic devices may have displays in which an array of pixels is covered with a transparent layer of glass. In some devices, a rear housing wall may be covered with a layer of glass. A decorative layer may be applied to the layer of glass to help improve the appearance of the rear housing wall. 
     SUMMARY 
     An electronic device may include electrical components and other components mounted within an interior of a housing. The device may have a display on a front face of the device and may have a glass housing wall on an opposing rear face of the device. The glass housing wall may be provided with regions having different appearances. The regions may be textured, may have coatings such as thin-film interference filter coatings formed from stacks of dielectric material having alternating indices of refraction, may have metal coating layers, and/or may have ink coating layers. 
     Textured surfaces, cavities, coatings, and other decoration may be embedded in glass structures that are joined with chemical bonds at diffusion-bonding interfaces. The decoration may, for example, be embedded in a glass housing wall having layers that are joined with chemical bonds at diffusion-bonding interfaces. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of an illustrative electronic device in accordance with an embodiment. 
         FIG.  2    is a cross-sectional side view of an illustrative electronic device in accordance with an embodiment. 
         FIG.  3    is a rear view of an illustrative electronic device in accordance with an embodiment. 
         FIG.  4    is a cross-sectional side view of an illustrative glass layer with an embedded coating layer in accordance with an embodiment. 
         FIG.  5    is a cross-sectional side view of an illustrative glass layer with an embedded cavity in accordance with an embodiment. 
         FIG.  6    is a cross-sectional side view of an illustrative glass layer with an embedded textured region in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices and other items may be provided with structures that are formed from transparent materials. For example, an electronic device may include a display. The display may have an array of pixels for displaying images for a user. To protect the pixel array from damage, the display may be covered with a layer of transparent material that serves as a display cover layer. The transparent material may be ceramic, polymer, crystalline material such as sapphire, or other suitable transparent material. Configurations in which such layers are formed from glass are sometimes described herein as an example. Portions of electronic devices such as optical windows, buttons, housing walls (e.g., rear housing walls and/or sidewalls), and other structures other than display cover layers may also be formed from ceramic, polymer, crystalline material such as sapphire, and/or glass and may be clear or may be colored. For example, the rear face of an electronic device may be covered with a layer of glass that forms a rear housing wall. 
     It may be desirable to locally and/or globally modify the appearance of a layer of glass (or other layer of material) in an electronic device. For example, it may be desirable to create attractive trim around a display, around the periphery of a camera window or button, or other suitable location. In some arrangements it may be desirable to selectively modify the appearance of a glass layer or other structure to form text, graphical patterns such as icons, logos, and/or other patterns visible to a user. 
     When creating structures such as these, there is a potential for unattractive features to develop on the glass layer. For example, if care is not taken, undesired shadowing may occur or surfaces may appear to sparkle excessively. 
     These concerns can be addressed by forming visually distinguishable areas on the glass layer (e.g., visually distinguishable regions for forming logos, text, etc.) using textured areas, neutrally colored or non-neutrally colored reflective coatings formed from a stack of alternating high and low index-of-refraction dielectric layers or other thin-film interference filter coatings (sometimes called dichroic layers or decoration layers), ink layers, adhesive layers, and/or other structures that selectively and/or globally impart visible changes to glass layers and other layers in an electronic device. 
     In forming the visually distinguishable areas, glass layers may be bonded together to form a solid glass layer with embedded decoration. For example, two or three layers of glass may be diffusion bonded by pressing polished surfaces of these layers into contact with each other and heating the layers to a temperature close to the glass transition temperature of the glass (e.g., within 10° C., within 50° C., or within another suitable amount). This causes the surfaces of the glass layers that are in contact with each other to chemically bond with each other, thereby fusing these glass layers together to form a single solid glass layer. Coatings, textures, cavities, and/or other structures may be formed on one or both of the mating surfaces of the layers of glass that are being bonded. In this way, patterns of visually distinguished structures (sometimes referred to as decoration) may be embedded within a glass housing wall or other layer of glass in an electronic device. 
     An illustrative electronic device of the type that may include diffusion-bonded glass structures with embedded patterned structures is shown in  FIG.  1   . Electronic device  10  may be a computing device such as 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 (e.g., a watch with a wrist strap), a pendant device, a headphone or earpiece device, a device embedded in eyeglasses or other equipment worn on a user&#39;s head, or other wearable or miniature device, 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. In the illustrative configuration of  FIG.  1   , device  10  is a portable device such as a cellular telephone, media player, tablet computer, wrist device, or other portable computing device. Other configurations may be used for device  10  if desired. The example of  FIG.  1    is merely illustrative. 
     In the example of  FIG.  1   , device  10  includes a display such as display  14  mounted in housing  12 . Housing  12 , which may sometimes be referred to as an enclosure or case, may be formed of plastic, glass, ceramics, fiber composites, metal (e.g., stainless steel, aluminum, titanium, gold, etc.), other suitable materials, or a combination of any two or more of these materials. Housing  12  may be formed using a unibody configuration in which some or all of housing  12  is machined or molded as a single structure or may be formed using multiple structures (e.g., an internal frame structure, one or more structures that form exterior housing surfaces, etc.). 
     Display  14  may be a touch screen display that incorporates a layer of conductive capacitive touch sensor electrodes or other touch sensor components (e.g., resistive touch sensor components, acoustic touch sensor components, force-based touch sensor components, light-based touch sensor components, etc.) or may be a display that is not touch-sensitive. Capacitive touch screen electrodes may be formed from an array of indium tin oxide pads or other transparent conductive structures. 
     Display  14  may include an array of pixels formed from liquid crystal display (LCD) components, an array of electrophoretic pixels, an array of plasma pixels, an array of organic light-emitting diode pixels or other light-emitting diodes, an array of electrowetting pixels, or pixels based on other display technologies. 
     Display  14  may include one or more layers of glass. For example, the outermost layer of display  14 , which may sometimes be referred to as a display cover layer, may be formed from a hard transparent material such as glass to help protect display  14  from damage. Other portions of device  10  such as portions of housing  12  and/or other structures may also be formed from glass. For example, walls in housing  12  such as a rear housing wall may be formed from glass. 
       FIG.  2    is a cross-sectional side view of an illustrative device that contains glass structures such as device  10  of  FIG.  1   . As shown in  FIG.  2   , device  10  may have opposing front and rear faces. Display  14  may be formed on the front face of device  10 . Housing  12  may have a rear housing wall formed from layer  24  on the opposing rear face of device  10 . Portions of housing  12  may also form sidewalls for device  10 . These sidewall portions of housing  12  may be formed from a material such metal (as an example). 
     Display  14  may include display cover layer  16  (e.g., a layer of glass) and display module  18  (e.g., display layers that form an array of pixels that present images for a user on the front face of device  10 ). Display module  18  may be a liquid crystal display structure, an organic light-emitting diode display structure, or other suitable display. During operation, module  18  may present images that are viewable through display cover layer  16 . The rear of the housing for device  10  may be formed from a glass structure (e.g., layer  24  may be a glass layer, sometimes referred to as a glass housing wall or glass housing layer). The thickness of layer  24  may be 0.2-5 mm, at least 0.05 mm, at least 0.1 mm, at least 0.2 mm, at least 0.5 mm, at least 0.75 mm, less than 1 mm, less than 2 mm, or other suitable thickness. 
     Layer  24  may be formed from multiple layers (e.g., multiple glass layers) that are bonded together. In this type of arrangement, layer  24  may have an outer layer and an inner layer. The outer layer may have a thickness of 0.2-5 mm, at least 0.05 mm, at least 0.1 mm, at least 0.2 mm, at least 0.5 mm, at least 0.75 mm, less than 1 mm, less than 2 mm, or other suitable thickness and the inner layer may have a thickness of 0.2-5 mm, at least 0.05 mm, at least 0.1 mm, at least 0.2 mm, at least 0.5 mm, at least 0.75 mm, less than 1 mm, less than 2 mm. The inner layer may be thicker than the outer layer in some configurations (e.g., the inner layer may be at least twice as thick as the outer layer, may be at least 5 times as thick as the outer layer, etc.). In other arrangements, the outer layer may be thicker than the inner layer. Arrangements in which layer  24  is formed from an outer layer, an inner layer, and an interposed intermediate layer may also be used. In these configurations, the intermediate layer may have a thickness 0.2-5 mm, at least 0.05 mm, at least 0.1 mm, at least 0.2 mm, at least 0.5 mm, at least 0.75 mm, less than 1 mm, less than 2 mm, or other suitable thickness. 
     If desired, a metal plate or other strengthening structures may be laminated to the inner surface of layer  24  to enhance strength. In some configurations, inner coating layers such as a layer of colored ink or other material may be formed on the inner surface of layer  24  (e.g., to adjust the outward appearance of layer  24 , to hide internal components from view, etc.). Internal components in device  10  such as components  22  (e.g., electrical components such as integrated circuits, sensors, etc.) may be mounted on one or more substrates such as printed circuit  20 . 
     Inactive border areas in layer  16  and portions of other glass structures in device  10  such as some or all of glass layer  24  may be covered with coatings and other structures. In some arrangements, a coating may be used primarily to block light (e.g., to hide internal device structures from view). For example, a coating may be formed on the inner surface of layer  24  to hide internal components from view from a user such as viewer  26  who is viewing device  10  in direction  28 . In other arrangements, a patterned coating may be used to form text, logos, trim, and/or other visible patterns. Coatings that are unpatterned and that coat all of glass layer  24  may also be used to block internal structures from view and/or to provide device  10  with a desired appearance. Patterned coatings may create visible elements and may also block internal structures from view. 
     Coatings for glass structures in device  10  may be black or other neutral colors or may have non-black (non-neutral) colors (e.g., blue, red, yellow, gold, rose gold, red-violet, pink, etc.). In some configurations, some or all of the coatings for glass structures in device  10  may be shiny (e.g., exhibiting a mirror-like reflective surface with a reflectance of at least 50%, at less 80%, at least 95%, less than 99.99%, or other suitable reflectance). 
     If desired, textured decoration may be formed for device  10  by texturing external glass surfaces of layer  24  and/or by texturing the surfaces of layers that are subsequently joined by diffusion bonding, thereby embedding the texture within the interior of layer  24 . In some configurations, layer  24  is provided with coatings on the exterior surfaces of layer  24 . Coatings can also be embedded in glass layer  24  (e.g., by depositing a coating on a glass layer surface of a glass layer and diffusion bonding that glass layer surface to a mating glass layer surface of another glass layer). 
     Coatings on glass layer  24  and/or other glass structures in device  10  may be formed from metals, semiconductors, and/or dielectrics. Dielectric materials for the coatings may include organic materials such as polymer layers and/or inorganic materials such as oxide layers, nitride layers, and/or other inorganic dielectric materials. In arrangements in which a shiny surface is desired, a metal coating with a high reflectivity or a thin-film interference filter with dielectric layers (e.g., a stack of dielectric layers of alternating higher and lower refractive index values) may be configured to serve as a mirror coating (reflective coating). Ink coatings may also be incorporated. 
       FIG.  3    is a top view of an illustrative configuration for the rear face of device  10  in which one region (region  24 - 1 ) has a first appearance (textured, shiny, a particular color, etc.) and has a first shape (e.g., text, a logo, a trim pattern, or other patterned shape) and in which another region (background region  24 - 2  in this example) has a second appearance (e.g., textured, shiny, a particular color, etc.). In order to ensure that region  24 - 1  is visible to a user of device  10 , the appearances of regions  24 - 1  and  24 - 2  may contrast with each other. For example, in a scenario in which region  24 - 1  is reflective (e.g., a scenario in which region  24 - 1  is a shiny silver or gold region associated with a logo, text, etc.), region  24 - 2  may have a matte finish. 
     Glass layer  24  may have any suitable number of separately patterned regions such as regions  24 - 1  and  24 - 2 , each of which may potentially have a different separate appearance. Configurations in which glass layer  24  has one or more patterned textured and shiny regions may sometimes be described herein as an example. The regions of device  10  that have different appearances may be formed by selectively patterning glass layer  24 , glass sublayers that are used in forming glass layer  24 , and associated coatings, films, and other structures for glass layer  24 . For example, these regions may be selectively formed by depositing coatings using physical vapor deposition, chemical vapor deposition, or other deposition techniques followed by photolithography and etching, using shadow-masking or other selective deposition techniques such as printing techniques, by using selective surface treatment such as selective laser treatment, selective roughening or polishing using mechanical or chemical-mechanical polishing equipment, selective treatment with machining equipment, sand-blasting equipment or blasting equipment using other particles, by roughening or otherwise processing the surfaces of polymer films using embossing tools, presses, and/or by using other equipment for selectively processing particular areas of coatings, films, and/or surfaces (e.g., glass layer surfaces). 
     Textured surfaces in layer  24  and/or in coatings, films, and/or other layers coupled to layer  24  may provide a matte finish. These textured surfaces may have protruding surface structures that are 100 s of nm to 1 micron in height (e.g., at least 100 nm, at least 500 nm, less than 5 microns, less than 1 micron). Such textured surfaces may have an RMS surface roughness of 100 nm to 2 microns or other suitable value that provides a desired appearance (e.g., a matte appearance). Smooth surfaces (e.g., polished surfaces or other smooth surfaces) may have protruding surface features that are less than 1 nm in height, less than 2 nm in height, less than 5 nm in height, less than 50 nm in height, etc.). Such smooth surfaces may have an RMS surface roughness of less the RMS surface roughness of the textured surfaces (e.g., an RMS surface roughness of less than 25 nm or other suitable value that provides a desired appearance such as a smooth potentially reflective appearance). To form satisfactory glass-glass chemical bonds during diffusion bonding, glass bonding surfaces may be polished to a smooth finish (e.g., to an RMS surface roughness of less than 2 nm, less than 1 nm, or other suitable roughness value associated with a smooth polished finish). If desired, regions of the rear housing wall of device  10  or other glass-layer structures may have other roughness values (e.g., values intermediate to those associated with strongly textured matte finishes and smooth reflective finishes). The use of textured and smooth surfaces to form visually distinct regions of glass layer  24  is merely illustrative. 
       FIGS.  4 ,  5  and  6    set forth various examples of patterned regions for a structure in device  10  such as a rear housing wall (e.g., glass layer  24 ) that have potentially different visual appearances. These regions may be used in forming logos, text, trim, and/or other patterns (sometimes referred to as decoration). There may be any suitable number of patterned regions on layer  24  and these layers may include textured backgrounds and smooth backgrounds, textured foregrounds and smooth backgrounds, background and foreground elements of different colors, reflectivity values, etc. Coatings may be provided on the outer surface of these illustrative patterned regions (e.g., antismudge coatings, antiscratch coatings, etc.) or, if desired, these external coating layers may be omitted and/or incorporated into the coatings, films, and surfaces forming layer  24 . The examples of  FIGS.  4 ,  5 , and  6    are merely illustrative. 
       FIG.  4    is a cross-sectional side view of glass layer  24  in an illustrative configuration in which glass layer  24  is formed by bonding together a pair of glass layers. In particular, glass layer  24 A and glass layer  24 B may have polished bonding surfaces that are joined and chemically bonded at diffusion-bonding interface  50  using glass diffusion bonding (e.g., chemical bonds may be formed between layers  24 A and  24 B at interface  50  by heating layers  24 A and  24  to a temperature close to the glass transition temperature of the glass material that forms layers  24 A and  24 B so that layers  24 A and  24 B join together to form a single glass housing wall such as layer  24 ). In addition to optionally patterning one or more of the exterior surfaces of glass layer  24 , internal patterned structures may be formed in layer  24 . These structures may be embedded within layer  24  by forming coatings, textures, recesses, and/or other features on one or both of the bonding surfaces associated with interface  50  (e.g., the lower surface of layer  24 A and/or the mating upper surface of layer  24 C) before these surfaces are bonded together. 
     In the illustrative example of  FIG.  4   , layer  24  has been patterned to form regions with different appearances. Region  38  may, for example, have a shiny appearance and optional textured region  42  may have a matte appearance due to the formation of a texture on the outer surface of layer  24 A. Region  40  may have an appearance that differs from that of region  38  and that of region  42  because coating layer  52  is embedded within layer  24  in region  40 . 
     Coating layer  52  may be formed on the lower (inwardly facing) surface of layer  24 A and/or on the outer (outwardly facing) surface of layer  24 C. Coating layer  52  may be deposited after surface polishing of layers  24 A and  24 C or, if desired, may be deposited in a recessed portion of layer  24 A and/or  24 C followed by surface polishing (e.g., to create a polished surface in which the outermost portion of coating layer  52  is flush with the surface of the glass layer (layer  24 A and/or  24 C) on which coating layer  52  has been deposited. 
     To ensure that coating layer  52  is not damaged during glass bonding operations associated with joining layers  24 A and  24 C, coating layer  52  may be formed from materials such as inorganic dielectric materials that can withstand elevated processing temperatures (e.g., silicon oxide, silicon nitride, titanium oxide, tantalum oxide, zirconium oxide, aluminum oxide, niobium oxide, and/or other inorganic dielectrics). Other materials (e.g., metals) can also be used in coating layer  52 , if desired. 
     With one illustrative configuration, coating layer  52  may be formed from a thin-film interference filter structure having a stack of dielectric layers. The layers in the dielectric stack may have alternating refractive index values and may be configured to form a thin-film interference filter (sometimes referred to as a dichroic filter) with a desired reflection and transmission spectrum. Coatings  52  may, in general, include one or more layers of material (e.g., one or more dielectric layers) and/or one or more different types of material (dielectric, conductive material, semiconductor, etc.). 
     As shown in  FIG.  4   , an optional coating layer such as coating layer  54  may be formed on the inner surface of layer  24 C. Coating layer  54  may be a global layer that covers all of the inner surface of layer  24  (as an example). Embedded coating layer  52  may be formed only in region  40  (as an example). Region  38 , which may surround region  40  may have an appearance that differs from that of regions  40  and  42 . Coating layer  54  may, if desired, be an ink layer (e.g., a polymer coating layer that includes colorant such as embedded pigment and/or dye), may be a dielectric stack that forms a thin-film interference filter, may be a metal layer, may be other coating layer(s), and/or may be formed from a combination of such layers. 
     Embedded coating  52  and rear coating  54  may be shiny. For example, a stack of multiple dielectric layers in coating  52  and/or  54  may have alternating index of refraction values to form a thin-film interference filter or coating  52  and/or coating  54  may include a reflective material such as metal. The texture of the outer surface of layer  24  in region  42  may provide glass layer  24  with a pleasing feeling to the touch. If desired, the texture of region  42  may overlap coating  52  and/or other portions of layer  24  or the texture of region  42  may be omitted. Coating  52  in region  40 , which may be a physical vapor deposition coating deposited through a shadow mask or other patterned layer, may be shaped to form text, a logo, or other visual element (decoration) and may provide layer  24  with a different appearance in region  40  that in regions  38  and  42 . Coating  54  (and, if desired, coating  52 ) may help hide internal components from view by blocking light transmission into the interior of device  10 . If desired, coating  54  may be formed from an opaque material such as neutrally colored (white, black, or gray) or non-neutrally colored (red, blue, yellow, etc.) ink. 
     In the illustrative configuration of  FIG.  5   , three separate glass layers  24 A,  24 B, and  24 C have been bonded together using diffusion bonding to form a single unified glass layer (glass layer  24 ) with an embedded cavity (cavity  62 ). Layer  24  may have regions with different appearances. For example, region  58 , which overlaps cavity  62 , may have a different appearance of than region  56 , which surrounds region  58 . 
     During glass bonding, the outer surface of glass layer  24 B may be diffusion bonded to the opposing inner surface of glass layer  24 A at interface  50 - 1  and the outer surface of glass layer  24 C may be bonded to the inner surface of layer  24 B at interface  50 - 2 . Following diffusion bonding, chemical bonds are formed at interfaces  50 - 1  and  50 - 2  so that layers  24 A,  24 B, and  24 C join to form a single piece of glass (layer  24 ). 
     As shown in  FIG.  5   , glass layer  24 B has an opening in region  58  (e.g., an opening in the shape of a logo, trim, and/or other decoration pattern). When glass layers  24 A,  24 B, and  24 C are bonded together, opening  62  becomes embedded within layer  24 . Cavity  62  may be filled with air or other gas. Optional coatings such as coatings  64  may be formed on the inner surface of layer  24 A in region  58  and/or on the outer surface of layer  24 C in region  58  (e.g., on an upper and/or lower cavity surface or other cavity surface such as a cavity sidewall surface). Coating(s)  64  may be a thin-film interference coating formed from a dielectric stack (e.g., inorganic materials that can withstand the elevated temperatures involved in diffusing bonding). Coating(s)  64  and cavity  62  may have a shape (an outline when viewed in direction  44 ) of a logo or other suitable shape. Optional rear coating  54  may be applied to the inner surface of layer  24  after high temperature processing is complete. 
     Another illustrative arrangement for layer  24  is shown in  FIG.  6   . In the example of  FIG.  6   , two glass layers  24 A and  24 C are diffusion bonded at interface  50  to form layer  24 . As shown in  FIG.  6   , a textured surface  76  is formed in region  72 , so that region  72  has a different appearance than region  70 . Textured surface  76  may be formed on the inner surface of layer  24 A and/or the outer surface of layer  24 C. In region  70 , the contacting (bonding) surfaces of layers  24 A and  24 C are polished to allow layers  24 A and  24 C to be joined together using diffusion bonding. After joining, textured surface  76  will form an internal texture that appears different than the bonded interface formed by joining the two polished surfaces of layers  24 A and  24 C. This is because textured surface  76  does not receive a good planar diffusion bond following diffusion bonding operations due to the lack of polish in textured surface  76 . As a result, textured surface  76  will effectively include small air gaps or pores after diffusion bonding operations are complete and theses air gaps provide surface  76  with a different appearance than the bonded interface in region  70 . Optional coating  78  may be formed on the polished and/or textured lower surface of layer  24 A in region  72  and/or may be formed on the polished and/or textured upper surface of layer  24 C in region  72 . Coating  78  may be a thin-film interference filter coating formed from a dielectric stack (e.g., a stack of inorganic dielectric materials of alternating index of refraction) and/or may include other materials such as metals. Coating  78  and other embedded coatings in layer  24  may be formed from materials that withstand damage at elevated temperatures (e.g., temperatures at or near the glass transition temperature of the glass material used to form layer  24 ). 
     As described in connection with  FIG.  5   , optional rear coating layer  54  may be formed over some or all of the rear surface of layer  24 C. As described in connection with  FIG.  4   , some or all of the upper surface of layer  24 A may be textured, as shown by the textured surface of region  42 . If desired, some or all of the rear surface of layer  24 C may be textured, selected areas of the upper surface of layer  24 A may be provided with coatings such as coating  54 , and/or other decoration structures may be formed for layer  24 . 
     The foregoing is merely illustrative and various modifications can be made to the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20180430
Publication Date: 20230704
Grant Date: 20230704
Priority Date: 20170731
Inventors: WILSON, JAMES R.
ROGERS, MATTHEW S.
Assignee: APPLE INC
CPC Classifications: [{"code": "G09F2003/0276", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K1/0306", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K5/03", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C27/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/0283", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B5/285", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09F3/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C17/22", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/0266", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K5/0243", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K5/0017", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K2201/0195", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09F9/30", "inventive": true, "first": true, "tree": "[]"}, {"code": "C03C17/22", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K1/0306", "inventive": true, "first": true, "tree": "[]"}, {"code": "H05K5/0243", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B17/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B17/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B7/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B3/30", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B2457/20", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2457/208", "inventive": false, "first": false, "tree": "[]"}, {"code": "B32B2457/202", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C27/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/0266", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04M1/0283", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B5/285", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C27/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K1/0306", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/0283", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B5/285", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K5/0243", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K5/03", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09F2003/0276", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K2201/0195", "inventive": false, "first": false, "tree": "[]"}, {"code": "H05K5/0017", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09F2003/0276", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09F3/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K2201/0195", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B5/285", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C17/22", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C27/10", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04M1/0266", "inventive": false, "first": false, "tree": "[]"}, {"code": "H04M1/0283", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K5/0243", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K5/03", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B7/12", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04M1/0266", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B7/023", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B3/30", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B17/1022", "inventive": true, "first": false, "tree": "[]"}, {"code": "B32B17/10238", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C17/22", "inventive": true, "first": false, "tree": "[]"}, {"code": "H05K5/0018", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09F9/30", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 65038444