PATENT DOCUMENT

Publication Number: US-10556823-B2
Application Number: US-201816000606-A
Country: US
Kind Code: B2

Title: Interior coatings for glass structures in electronic devices

Abstract:
An electronic device may include electrical components and other components mounted within a housing. The device may have a display on a front face of the device and may have a glass layer that forms part of the housing on a rear face of the device. The glass layer and other glass structures in the electronic device may be provided with coatings. An interior coating on a glass layer may include multiple layers of material such as an adhesion promotion layer, thin-film layers of materials such as silicon, niobium oxide and other metal oxides, and metals to help adjust the appearance of the coating. A metal layer may be formed on top of the coating to serve as an environmental protection layer and opacity enhancement layer. In some configurations, the coating may include four layers.

Claims:
What is claimed is: 
     
       1. An electronic device having opposing front and rear faces, comprising:
 a display on the front face; 
 a housing having a glass layer on the rear face; and 
 a coating on the glass layer, wherein the coating includes a first layer on an interior surface of the glass layer, a second layer, and a third layer that is interposed between the first and second layers and that is formed from a material that is different from at least one of the first and second layers, wherein the first layer comprises a metal adhesion promotion layer. 
 
     
     
       2. The electronic device defined in  claim 1  wherein the second layer is configured to environmentally protect the coating from exposure to air. 
     
     
       3. The electronic device defined in  claim 2  wherein the third layer comprises a metal oxide. 
     
     
       4. The electronic device defined in  claim 3  wherein the metal oxide comprises niobium oxide. 
     
     
       5. The electronic device defined in  claim 2  wherein the third layer comprises silicon. 
     
     
       6. The electronic device defined in  claim 5  further comprising a fourth layer interposed between the first and second layers, wherein the fourth layer comprises a metal oxide. 
     
     
       7. The electronic device defined in  claim 6  wherein the fourth layer comprises niobium oxide. 
     
     
       8. The electronic device defined in  claim 2  wherein the third layer comprises a metal. 
     
     
       9. The electronic device defined in  claim 2  wherein the third layer comprises a metal selected from the group consisting of tin, copper, and aluminum. 
     
     
       10. The electronic device defined in  claim 1  wherein the second layer comprises titanium. 
     
     
       11. The electronic device defined in  claim 10  wherein the first layer comprises titanium. 
     
     
       12. The electronic device defined in  claim 1  wherein the first and second layers are formed from a common material. 
     
     
       13. The electronic device defined in  claim 12  wherein the common material is titanium and wherein the first layer has a thickness of less than 20 nm. 
     
     
       14. An electronic device having opposing front and rear faces, comprising:
 a display on the front face; 
 a housing having a glass layer on the rear face; and 
 a coating on the glass layer, wherein the coating includes a first layer on an interior surface of the glass layer, a second layer, and a third layer that is interposed between the first and second layers and that is formed from a material that is different from at least one of the first and second layers, wherein the first layer has a first thickness, the second layer has a second thickness, the third layer has a third thickness, the second layer comprises a metal oxide layer, and the ratio of a sum of the first and third thicknesses to the second thickness is at least one. 
 
     
     
       15. The electronic device defined in  claim 14  wherein the first and third layers are formed from different metals. 
     
     
       16. The electronic device defined in  claim 15  wherein the first layer comprises a titanium layer. 
     
     
       17. The electronic device defined in  claim 16  wherein the third layer comprises a copper layer. 
     
     
       18. The electronic device defined in  claim 17  wherein the second layer comprises a niobium oxide layer. 
     
     
       19. The electronic device defined in  claim 1  wherein the first layer has a first thickness, the second layer has a second thickness, the third layer has a third thickness, and the ratio of the first thickness to a sum of the second and third thicknesses is at least 1.5. 
     
     
       20. The electronic device defined in  claim 19  wherein the first layer comprises a metal layer. 
     
     
       21. The electronic device defined in  claim 20  wherein the second layer comprises a metal oxide layer. 
     
     
       22. The electronic device defined in  claim 21  wherein the third layer comprises a layer that is not a metal layer. 
     
     
       23. The electronic device defined in  claim 22  wherein the third layer comprises a silicon layer. 
     
     
       24. The electronic device defined in  claim 23  wherein the second layer comprises a niobium oxide layer. 
     
     
       25. The electronic device defined in  claim 24  wherein the first layer comprises a titanium layer. 
     
     
       26. The electronic device defined in claim  20  wherein the third layer comprises a metal oxide layer. 
     
     
       27. The electronic device defined in  claim 26  wherein the second layer comprises a layer that is not a metal layer. 
     
     
       28. The electronic device defined in  claim 27  wherein the second layer comprises a silicon layer. 
     
     
       29. The electronic device defined in  claim 28  wherein the third layer comprises a niobium oxide layer. 
     
     
       30. The electronic device defined in  claim 29  wherein the first layer comprises titanium. 
     
     
       31. An electronic device, comprising:
 a housing wall including at least one glass layer; and 
 a coating on the glass layer that includes:
 a first layer on the glass layer; 
 a second layer on the first layer; 
 a third layer on the second layer; and 
 a fourth layer on the third layer, wherein the second and third layers are formed from different materials than the first and fourth layers. 
 
 
     
     
       32. The electronic device defined in  claim 31  wherein the first layer comprises a metal layer and wherein at least one of the second and third layers is a metal oxide. 
     
     
       33. The electronic device defined in  claim 32  wherein the second and third layers are formed from different materials. 
     
     
       34. The electronic device defined in  claim 33  wherein at least one of the second and third layers comprises a metal. 
     
     
       35. The electronic device defined in  claim 34  wherein at least one of the second and third layers comprises silicon. 
     
     
       36. Apparatus, comprising:
 at least one glass structure; and 
 a coating on the glass structure that includes:
 a first layer on the glass layer, wherein the first layer is a metal layer; 
 a second layer on the first layer; 
 a third layer on the second layer; and 
 a fourth layer on the third layer, wherein the second and third layers are formed from different materials than the first and fourth layers, wherein the fourth layer is a metal layer, and wherein at least one of the second and third layers is a layer of metal oxide.

Description:
This patent application claims the benefit of provisional patent application No. 62/522,561, filed on Jun. 20, 2017, which is hereby incorporated by reference herein in its entirety. 
    
    
     BACKGROUND 
     This relates generally to coatings, and, more particularly, to coatings for 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. 
     If care is not taken, glass structures may be susceptible to cracking when subjected to elevated stress such as during an unintended drop event. The appearance of a glass structure in an electronic device can be improved by forming a thin-film coating on the glass structure. However, the presence of thin-film coatings on an inner glass surface has the potential to create stress concentrations that make the glass structure susceptible to breakage. 
     SUMMARY 
     An electronic device may include electrical components and other components mounted within a housing. The device may include glass structures. As an example, the device may have a display on a front face of the device and may have a glass layer that forms part of the housing on a rear face of the device. The glass layer and other glass structures in the electronic device may be provided with coatings. An interior coating on a glass layer may include multiple layers of material such as an adhesion promotion layer, thin-film layers of materials such as silicon, niobium oxide and other metal oxides, and metals to help adjust the appearance of the coating and therefore the appearance of the electronic device. A metal layer may be formed on top of the coating to serve as an environmental protection layer and opacity enhancement layer. 
     In some configurations, the coating may include four layers of material. These layers may include a layer on an inner surface of the glass layer. This layer may be formed from a material such as titanium that serves as an adhesion promotion layer. The thickness of high-modulus materials such as titanium on the inner surface of the glass layer may be limited to a relatively small value to prevent these materials from imparting stress to the glass. The titanium layer and/or additional layers in the coating may serve as a buffer layer that prevents stress from brittle materials such as metal oxides and other materials in the coating from adversely affecting the strength of the glass layer. Soft metals such as copper may be used in the buffer layer and/or elsewhere in the coating to adjust color and help block stress. A titanium capping layer or other capping layer may be used as in the coating to prevent degradation to the coating from air exposure and to ensure that the coating has a desired opacity. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an illustrative electronic device of the type that may include a glass structure with a coating in accordance with an embodiment. 
         FIG. 2  is a cross-sectional side view of an illustrative electronic device with a coating in accordance with an embodiment. 
         FIGS. 3, 4, and 5  are illustrative glass layers with coatings in accordance with embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices and other items may be provided with structures that are formed from glass. 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 glass that serves as a display cover layer. Other portions of electronic devices may also include glass structures. For example, the rear face of an electronic device may be covered with a layer of glass. In this type of arrangement, the glass forms a housing surface that is pleasing to the touch. Glass structures may also be used as optical windows, buttons, and/or other structures in an electronic device. 
     It may be desirable to form a coating layer on a glass structure to change the appearance of the glass structure. As an example, a blanket coating layer or a patterned coating layer in the shape of a logo, decorative trim, text, or other shape may be formed on the interior surface of a glass layer in an electronic device. The coating may be reflective, may exhibit an appearance with a desired color, may help block internal device components from view, and/or may have other desired optical properties. By forming the coating on the interior of the glass layer, damage to the coating from scratches may be reduced. Configurations in which glass coatings are formed on exterior surfaces of a glass structure may also be used. 
     An illustrative electronic device of the type that may include glass 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 . In the illustrative configuration for device  10  of  FIG. 2 , housing  12  of device  10  has portions that define 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 such as glass layer  24 . 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 . 
     To hide internal components such as components  22  from view, 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. In some arrangements, a coating may be used primarily to block light (e.g., to hide internal device structures from view). In other arrangements, a patterned coating may be used to form text, logos, trim, and/or other decorative patterns. Coatings for glass structures in device  10  may be black or may have non-black colors (e.g., blue, red, yellow, gold, rose gold, red-violet, pink, etc.). If desired, coatings for glass structures in device  10  may be shiny. Coatings on glass layer  24  and/or other glass structures in device  10  may be formed from metals, semiconductors, and/or dielectrics. 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. 
     If care is not taken, the presence of a coating layer on a glass structure such as layer  24  can predispose the glass structure to damage. For example, the likelihood that a glass structure in device  10  will become damaged when exposed to a large amount of stress during a drop event or other event that creates stress on the glass structure can be increased by the presence of a brittle coating layer. Cracks may form in the brittle coating layer and these cracks may create stress concentrations at the interface between the coating layer and the glass that can propagate into the glass during a drop event. 
     To ensure that a glass structure in device  10  such as layer  24  has a satisfactorily large strength to withstand the stresses encountered during use of device  10 , coatings on layer  24  may be formed using configurations that reduce coating-induced stress. 
     In one illustrative arrangement, some or all of the layers of material in a coating on glass layer  24  may be formed from material that have a Young&#39;s modulus of elasticity that matches that of glass layer  24 . Glass layer  24  may, as an example, have an elastic modulus (Young&#39;s modulus) of 70 GPa. Coating-induced stress may be reduced by forming coatings on glass layer  24  from a material having a Young&#39;s modulus that is within 20%, within 10%, within 5%, or other suitable amount of 70 GPa. As an example, a reflective coating on glass layer  24  may be formed from an aluminum layer (Young&#39;s modulus 69-70 GPa). Other examples of materials having modulus values that are close to that of glass layer  24  include tin and copper. 
     Layers with mismatched elastic modulus values (e.g., material with an elastic modulus of 200 GPa) will tend to generate undesirable stress on layer  24  unless the thickness of these layers has a suitably low value. If, as an example, a layer of titanium (which has a high modulus) is used as a coating on layer  24 , the layer of titanium may be formed to a thickness of 5-10 nm, less than 20 nm, less than 50 nm, at least 1 nm, or other value that is suitably low to ensure that excessive stress is not imparted to glass layer  24 . Titanium layers of 100 nm and above that are formed directly on the surface of a glass layer may impart more stress to the glass layer than desired. 
     In another illustrative configuration, potentially brittle materials such as metal oxides may be used in a coating on glass layer  24  provided that a buffer layer of a ductile material such as metal is formed between the brittle material and glass layer  24 . If, as an example, niobium oxide layer is being used in a coating to generate thin-film interference effects and thereby help a coating produce a desired appearance (e.g., a desired color) when observed through glass layer  24 , a softer material such as copper may be interposed between the niobium oxide layer and glass layer  24  to help reduce the amount of stress imparted by the niobium layer to glass layer  24 . Soft materials such as copper or other soft metals (Al, Sn, etc.) may also be interposed between brittle coating materials (e.g., brittle inorganic layers) in a coating and glass  24  to help protect glass layer  24 . In some configurations, thin layers of metals such as titanium may be used as buffer layers for brittle layers such as niobium oxide layers. 
     Using stress mitigation techniques such as these may allow coatings to be formed on the interior surface of glass layer  24  and/or on other glass structures in device  10  without unduly increasing risks of damage when device  10  is dropped or otherwise subjected to high stress events. 
     An illustrative coating configuration for glass layer  24  that includes a brittle inorganic material such as a metal oxide is shown in  FIG. 3 . As shown in the example of  FIG. 3 , coating  30  may be formed on the inner surface of glass layer  24 . Glass layer  24  (e.g., a housing wall structure such as glass layer  24  of  FIG. 2 ) may have a thickness in the Z dimension of 800 microns, at least 300 microns, at least 500 microns, at least 600 microns, less than 2000 microns, less than 1200 microns, less than 1000 microns, or other suitable thickness. Layer  30  may have a thickness of at least 10 nm, at least 50 nm, at least 250 nm, less than 500 nm, less than 100 nm, or other suitable thickness. 
     In the example of  FIG. 3 , layer  30  includes four layers. Configurations for layer  30  that include at least two layers, at least three layers, at least four layers, at least five layers, or fewer six layers may be used, if desired. Layer  30  may be deposited by physical vapor deposition techniques or other suitable fabrication techniques. Shadow masking, photolithography, and/or other patterning techniques may optionally be used to form coatings on glass layer  24 , if desired (e.g., these patterning techniques may be used to pattern layer  30  of  FIG. 3 ). 
     The materials and the thicknesses of the materials that make up layers  30  may be configured to reduce stress on glass layer  24  while producing a coating on the interior surface of glass layer  24  that presents a desired appearance as layer  30  is viewed through layer  24  by a user of device  10 . In some situations, layer  30  may be configured to exhibit a rose gold appearance or a red-violet (blush) appearance. Other colors can be produced by adjusting the thicknesses and materials of the layers that make up layer  30 . The use of coating layer  30  to produce a rose gold or red-violet appearance for the rear housing wall of device  10  is merely illustrative. 
     In the illustrative configuration of  FIG. 3 , layer  32  is a layer of a metal such as titanium. Layer  32  may have a thickness of 5-7 nm, at least 2 nm, at least 3 nm, less than 15 nm, less than 10 nm, or other suitable thickness. Layer  32  may serve as an adhesion promotion layer for coating  30 . Titanium for layer  32  can be deposited by sputtering (as an example) to form a stable base layer for coating layer  30 . The thickness of layer  32  of  FIG. 3  is not large enough to render layer  32  completely opaque, so additional layers in layer  30  can be configured to adjust the appearance of layer  30 . 
     Layer  34  may be deposited on layer  32 . In the illustrative configuration of  FIG. 3 , layer  34  is an inorganic dielectric layer that is used in adjusting the appearance of layer  30  (e.g., the color of layer  30 ). Layer  34  may be, for example, a metal oxide such as niobium oxide. The thickness of layer  34  may 3-6 nm, at least 1 nm, at least 2 nm, at least 3 nm, less than 20 nm, less than 7 nm, or other suitable thickness. When layer  34  is formed from a material such as niobium oxide, layer  34  will be relatively brittle. Titanium layer  32 , which is sufficiently thin to avoid imposing undesired stress on layer  24 , serves as a ductile buffer layer that helps reduce stress on layer  24  from layer  34 . In configurations of this type in which a buffer layer in coating  30  is formed from a material such as titanium or other metal with a relatively higher elastic modulus (e.g., over 75 GPa or over 100 GPa), it may be desirable for the ratio of the thickness Ta of the buffer layer material (e.g., the thickness of layer  32  of  FIG. 3 ) to the thickness Tb of the brittle material (e.g., the thickness of layer  34 ) to be greater than 1.5. When this minimum ratio of Ta to Tb is observed, coating layer  30  will not excessively weaken glass layer  24 . 
     Layer  36  of coating layer  30  of  FIG. 3  may be formed from a metal such as copper that helps impart a desired color to layer  30  and that may block stress from subsequently deposited layers such as layer  38 . The thickness of layer  36  may be 24-35 nm, at least 10 nm, at least 15 nm, less than 70 nm, less than 40 nm, or other suitable thickness. 
     Layer  38  may be formed on layer  36 . Layer  38  may be formed from a material such as titanium and may have a thickness of 50 nm, at least 10 nm, at least 20 nm, at least 30 nm, at least 40 nm, less than 100 nm, less than 75 nm, or less than 60 nm. The innermost surface of coating  30  (the surface of coating  30  facing interior components such as components  22  of device  10  of  FIG. 2 ) may be exposed to air in the interior of device  10 . Exposed copper can react with air and is therefore not highly stable. By forming layer  38  on top of layer  36 , coating  30  is protected from environmental degradation. The opacity of layer  30  and therefore the ability of layer  30  to prevent external viewing of internal device components through layer  24  and layer  30  can also be enhanced by the presence of layer  38 . T 
     The protective metal of layer  38  (e.g., titanium) may have a high modulus, so the presence of a soft underlying layer such as copper layer  36  may help reduce any stress imparted to layer  24  by layer  38 . To adjust the color of coating layer  30 , the relative thicknesses and types of materials used for layers  32 ,  34 ,  36 , and  38  may be adjusted (e.g., to adjust thin-film interference effects and/or bulk spectral effects associated with these layer). In some configurations, additional layers and/or fewer layers may be used in forming coating layer  30 . The arrangement of  FIG. 3  is illustrative. 
     If desired, soft metals (e.g., copper, tin, silver, etc.) may be placed between a brittle layer such as a niobium oxide layer and glass  24 . For example, in coating layer  30 , layer  34  may be a copper layer (e.g., e.g., a copper layer of at least 5 nm in thickness, of less than 50 nm of thickness, or other suitable thickness) and layer  36  may be a niobium oxide layer (e.g., a layer of at least 5 nm in thickness, of less than 10 nm in thickness, or other suitable thickness). In this type of arrangement, the titanium and copper layers at the bottom of layer  30  serve as a buffer layer of collective thickness Ta that blocks stress from the overlying niobium oxide layer of thickness Tb. In situations such as these in which the buffer layer in coating layer  30  contains soft metals, the ratio of Ta to Tb should generally be at least 1.0 to block stress effectively. 
     Another illustrative coating configuration for glass layer  24  is shown in  FIG. 4 . In this example, coating layer (coating)  40  has layers such as layers  42 ,  44 ,  46 , and  48 . There may be at least two layers of material in layer  40 , at least three layers, at least four layers, at least five layers, fewer than six layers, or other suitable number of layers in layer  40  to achieve a desired appearance for layer  40  when viewed by a user through glass layer  24 . With one illustrative configuration, the layers of layer  40  are configured so that layer  40  imparts a dark gray appearance to device  10  when viewed through glass layer  24 . Other colors may be produced by layer  40 , if desired (e.g., black, bluish black, silver, etc.). 
     Layer  42  may be a metal layer such as a titanium layer that serves as an adhesion promotion layer for layer  40 . The thickness of layer  42  may be 15-20 nm, at least 5 nm, at least 10 nm, less than 20 nm, less than 30 nm, less than 25 nm, or other suitable thickness. 
     Layers  44  and  46  may be formed from inorganic materials. For example, layer  44  may be formed from a material such as silicon or a material such as niobium oxide or other inorganic dielectric material (e.g., metal oxides, etc.). Layer  46  may be formed from a material that allows layers  44  and  46  and the other thin-film layers of coating layer  40  to produce a desired color for device  10  (e.g., through thin-film interference effects and other optical effects). For example, if layer  44  is a silicon layer, layer  46  may be a niobium oxide layer and if layer  44  is a niobium oxide layer, layer  46  may be a silicon layer. The thickness of layer  44  may be 5-8 nm, at least 2 nm, at least 4 nm, less than 20 nm, less than 10 nm, or other suitable thickness. The thickness of layer  46  may be 7-8 nm, at least 3 nm, at least 5 nm, less than 20 nm, less than 10 nm, or other suitable thickness. 
     Layer  48  may be formed on layer  46  to provide layer  40  with environmental protection and a desired opacity. Layer  48  may be, for example, a layer of titanium having a thickness of 50 nm, at least 10 nm, at least 30 nm, at least 40 nm, less than 75 nm, or other suitable thickness. 
     In a configuration of the type shown in  FIG. 4 , layer  42  may serve as a metal buffer layer that helps block excess stress from brittle layers such as layers  44  and  46 . To help ensure that layer  42  adequately buffers stress from layers  44  and  46 , the ratio of the thickness Ta of titanium layer  42  to the collective thickness Tb of brittle material in coating  40  (e.g., the collective thickness of layers  44  and  46 ) may be greater than 1.5. 
     In some configurations, coatings on layer  24  may include organic materials such as colored ink. As shown in  FIG. 5 , for example, coating  50  may include ink layer  58  on top of one or more other layers such as layers  52 ,  54 , and  56 . Layer  58  may be coated with a titanium layer or other environmental capping layer or may be left uncovered. 
     Layer  52  of  FIG. 5  may be an adhesion promotion layer formed from a metal such as titanium (e.g., a titanium layer of at least 5 nm in thickness, of less than 10 nm in thickness, less than 20 nm in thickness, or other suitable thickness). Layer  54  may be a copper layer or other soft metal layer (e.g., a layer of at least 5 nm in thickness, less than 50 nm in thickness, or other suitable thickness) and layer  56  may be a niobium oxide layer, other metal oxide layer, or other layer of material (e.g., a layer having a thickness of at least 5 nm, of less than 10 nm, or other suitable thickness) for helping to produce thin-film interference effects to adjust color. If desired, layer  56  may be a copper layer or other soft metal layer (e.g., a layer of at least 5 nm in thickness, less than 50 nm in thickness, or other suitable thickness) and layer  54  may be a niobium oxide layer, other metal oxide layer, or other layer of material (e.g., a layer having a thickness of at least 5 nm, of less than 10 nm, or other suitable thickness) for helping to produce thin-film interference effects to adjust color. Layer  58  may be formed from a polymer binder that contains dye and/or pigment of desired colors to help adjust the appearance of layer  50 . 
     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: 20180605
Publication Date: 20200211
Grant Date: 20200211
Priority Date: 20170620
Inventors: ROGERS, MATTHEW S.
NGUYEN, Que Anh S.
Assignee: APPLE INC
CPC Classifications: [{"code": "C03C2217/72", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C17/3615", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C2218/36", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C17/3652", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C17/3684", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C17/3649", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C2217/445", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C2217/485", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C17/36", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C17/38", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C17/3668", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C17/3649", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C17/3639", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C17/3636", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C17/3615", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C17/36", "inventive": true, "first": true, "tree": "[]"}, {"code": "C03C2217/478", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C2217/258", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C2217/253", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C2217/28", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C2217/78", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C2218/36", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C17/3684", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C17/3639", "inventive": true, "first": true, "tree": "[]"}, {"code": "C03C2217/485", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C2217/218", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C17/3652", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C17/3649", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C2217/445", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C2217/212", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C2217/72", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C17/3615", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C17/38", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C2217/90", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C17/3636", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C17/3639", "inventive": true, "first": true, "tree": "[]"}, {"code": "C03C2217/258", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C2217/90", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C2217/212", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C2217/218", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C2217/28", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C2217/253", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C2217/478", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C17/3636", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C2217/78", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C2218/36", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C2217/90", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C2217/78", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C2217/72", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C2217/485", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C2217/478", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C2217/445", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C2217/28", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C2217/258", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C2217/253", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C2217/218", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C2217/212", "inventive": false, "first": false, "tree": "[]"}, {"code": "C03C17/38", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C17/3684", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C17/3649", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C17/3615", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C17/36", "inventive": true, "first": true, "tree": "[]"}, {"code": "B32B17/06", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C17/3652", "inventive": true, "first": false, "tree": "[]"}, {"code": "C03C17/36", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 62715874