PATENT DOCUMENT

Publication Number: US-10482305-B1
Application Number: US-201615170818-A
Country: US
Kind Code: B1

Title: Electronic devices with thin-film masking layers

Abstract:
An electronic device may have transparent structures. The transparent structures may include a transparent member such as a transparent button member. The transparent member may have an inner surface that is covered with an opaque masking layer. The opaque masking layer may be white and may include a white porous inorganic layer covered with an opaque layer that increases the optical density of the opaque masking layer. The white porous inorganic layer may be formed by depositing a metal or other material using physical vapor deposition followed by an annealing process in the presence of oxygen. The opaque layer may be an optically dense inorganic layer such as a metal oxide layer. The button member may be located within an opening in a display cover layer. A fingerprint sensor may be attached to the opaque layer on the button member.

Claims:
What is claimed is: 
     
       1. An electronic device, comprising:
 a transparent member; and 
 opaque masking structures on the transparent member that contain a porous inorganic layer, wherein the porous inorganic layer is in direct contact with the transparent member. 
 
     
     
       2. The electronic device defined in  claim 1  wherein the porous inorganic layer comprises a white layer. 
     
     
       3. The electronic device defined in  claim 1  wherein the porous inorganic layer comprises a white layer deposited by physical vapor deposition and annealed to oxidize the porous inorganic layer. 
     
     
       4. The electronic device defined in  claim 3  wherein the opaque masking structures include an opaque layer directly on the porous inorganic layer. 
     
     
       5. The electronic device defined in  claim 4  wherein the porous inorganic layer comprises a layer of porous titanium oxide. 
     
     
       6. The electronic device defined in  claim 5  wherein the opaque layer comprises a layer of zirconium oxide. 
     
     
       7. The electronic device defined in  claim 4  wherein the opaque layer comprises an inorganic opaque layer. 
     
     
       8. The electronic device defined in  claim 7  wherein the transparent member comprises a button member. 
     
     
       9. The electronic device defined in  claim 8  further comprising:
 a display, wherein the display has a display cover layer with an opening and wherein the button member is located in the opening. 
 
     
     
       10. The electronic device defined in claim  9  further comprising a sensor that is attached to the opaque layer. 
     
     
       11. The electronic device defined in  claim 10  wherein the sensor is a fingerprint sensor. 
     
     
       12. Apparatus, comprising:
 a transparent member; 
 an inorganic white opaque masking layer on the transparent member, wherein the inorganic white opaque masking layer includes a porous oxidized metal layer directly on the transparent member and a metal oxide layer directly on the oxidized metal layer; and 
 a sensor coupled to the inorganic white opaque masking layer. 
 
     
     
       13. The apparatus defined in  claim 12  wherein the porous oxidized metal layer is a porous white layer and the metal oxide layer is an opaque layer. 
     
     
       14. The apparatus defined in  claim 13  further comprising a display cover layer with an opening, wherein the transparent member comprises a button member in the opening.

Description:
This application claims the benefit of provisional patent application No. 62/275,564 filed on Jan. 6, 2016, which is hereby incorporated by reference herein in its entirety. 
    
    
     FIELD 
     This relates generally to electronic devices and, more particularly, to masking layers for coating transparent structures in electronic devices. 
     BACKGROUND 
     Electronic devices sometimes contain transparent structures. For example, the display in a cellular telephone may be covered with a layer of glass. Cosmetic coatings such as masking layers of black and white ink are sometimes formed on the inner surfaces of the glass layer. In some devices, transparent button members may be coated with ink layers. 
     If care is not taken, the masking material that is used to coat a transparent structure in an electronic device may be prone to discoloration. For example, white ink layers that contain titanium oxide particles may acquire a bluish tint upon exposure to ultraviolet light. 
     SUMMARY 
     An electronic device may have transparent structures. The transparent structures may include a transparent member such as a transparent button member. The electronic device may have a display with a display cover layer. The transparent button member may be located in an opening in the display cover layer. 
     The transparent member may have an inner surface that is covered with an opaque masking layer. The opaque masking layer may be white. The opaque masking layer may be formed from inorganic layers. The inorganic layers may be deposited using physical vapor deposition and other fabrication techniques. 
     The opaque masking layer may include a white porous inorganic layer. The opaque masking layer may also have an opaque layer that covers the white porous inorganic layer to increase the optical density of the opaque masking layer. 
     The white porous inorganic layer may be formed by depositing a solid layer of metal or other material using physical vapor deposition followed by an annealing process in the presence of oxygen to form a porous layer that scatters light. The opaque layer may be an optically dense inorganic layer such as a metal oxide layer. 
     A sensor may be coupled to the transparent member. For example, a fingerprint sensor may be attached to the opaque layer on a transparent button member using a layer of adhesive. 
    
    
     
       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 a portion of an illustrative electronic device with a button member in accordance with an embodiment. 
         FIG. 3  is a diagram showing equipment and operations involved in forming an opaque masking layer on the underside of a transparent structure such as a button member in accordance with an embodiment. 
         FIG. 4  is a flow chart of illustrative operations involved in forming electronic devices with opaque masking layers on transparent members in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Electronic devices may be provided with opaque layers of material. The opaque layers of material, which may sometimes be referred to as opaque masking layers, masking layers, or masking structures may be white, black, gray, or may have other suitable colors. Configurations in which the opaque layers are white may sometimes be described herein as an example. This is, however, merely illustrative. Coatings for electronic devices may have any suitable appearance. 
       FIG. 1  is a perspective view of an illustrative electronic device of the type that may include an opaque masking layer. 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 wrist-watch device, 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, an accessory (e.g., earbuds, a remote control, a wireless trackpad, etc.), 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, 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 display  14 . Display  14  has been 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, 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.). Openings may be formed in housing  12  to form communications ports, holes for buttons, and other structures. 
     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 sensor 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 display pixels, an array of organic light-emitting diode pixels or other light-emitting diode pixels, an array of electrowetting pixels, or pixels based on other display technologies. 
     Display  14  may be protected using a display cover layer such as a layer of transparent glass, clear plastic, transparent ceramic, sapphire or other transparent crystalline material, or other transparent layer(s). The display cover layer may have a planar shape, a convex curved profile, a concave curved profile, a shape with planar and curved portions, a layout that includes a planar main area surrounded on one or more edges with a portion that is bent out of the plane of the planar main area, or other suitable shape. An opening may be formed in the display cover layer to accommodate ports such as speaker port  18 . 
     One or more additional openings may also be formed in the display cover layer. For example, an opening may be formed in the display cover layer to accommodate a button such as button  16 . Button  16  may be formed from a transparent button member that moves within the opening in the display cover layer. The button member may be circular, may be square, or may have other suitable shapes and may be formed from the same material as the display cover layer or other suitable materials. With one illustrative arrangement, which may sometimes be described herein as an example, button  16  may have a button member formed from a transparent layer such as a layer of sapphire. An opaque masking layer may be formed on the underside of the button member and on portions of the display cover layer for display  14  (e.g., on the inner surface of the display cover layer in inactive area IA of display  14 ). Other configurations may be used for display  14 , if desired (e.g., button  16  may be formed from an integral region of the display cover layer, etc.). 
       FIG. 2  is a cross-sectional side view of a portion of device  10  of  FIG. 1  in the vicinity of button  16  taken along line  20  of  FIG. 1  and viewed in direction  22 . As shown in  FIG. 2 , opaque masking structures such as opaque masking layer  24  may be formed on the underside of button member  26  in button  16  and on the underside of display cover layer  36  (e.g., in the portions of display cover layer  36  shown by opaque masking structures  24 ′ of  FIG. 2  and inactive area IA of  FIG. 1 ). The opaque masking structures on button member  26  may be the same as the opaque masking structures in regions  24 ′ on the underside of display cover layer  36  or the masking structures in region  24 ′ may be formed from using a first configuration (e.g., an opaque ink layer) and the structures under button member  26  may be formed using a second configuration (e.g., inorganic layers formed using techniques such as physical vapor deposition layer). 
     Button member  26  may be transparent. Opaque masking layer  24  may block visible light. For example, opaque masking layer  24  may be a white layer that blocks internal components under member  26  from view. Layer  24  may be opaque or transparent at infrared wavelengths. Configurations for device  10  in which layer  24  is formed under a transparent member such as button member  26  may sometimes be described herein as an example. In general, masking layer  24  may be formed on the surface of any suitable structure in device  10 . 
     Button member  26  may be formed from a transparent structure such as a layer of sapphire, glass, or plastic (as examples). During operation, a user may press against button member  26 , causing button member  26  to move in the −Z direction (e.g., to actuate a tactile switch or other device under button member  26 ). To provide button  16  with the ability to gather user fingerprints, button  16  may have a sensor such as fingerprint sensor  34 . Fingerprint sensor  34  may, for example, be a capacitive sensor (i.e., a capacitive touch sensor) that has an array of capacitive touch sensor electrodes. Sensor  34  may be formed from a semiconductor die (e.g., a silicon integrated circuit) and may be coupled to control circuitry within device  10  using a flexible printed circuit cable or other signal path. 
     Sensor  34  may be mounted to the inner surface of opaque masking structures  24  using adhesive  32 . Adhesive  32  may be a rigid adhesive such as a cured liquid adhesive (e.g., epoxy, a silicone-epoxy hybrid with a high cross-link density, etc.), may be a layer of pressure sensitive adhesive, or may be other suitable adhesive. If desired, button  16  may be formed from an integral portion of the display cover layer for display  14  and/or may have a strain gauge or other sensor for detecting when a user has pressed on button  16 . The use of a configuration for button  16  with a movable button member and an associated tactile switch is merely illustrative. 
     Opaque masking structures  24  may include layers such as layers  28  and  30 . Layers  28  and  30  may be formed as coating layers on the inner surface of button member  26  (and the inner surface of display cover layer  36  and/or other transparent structures in device  10 ). Layer  28  may be a light-scattering layer such as a white layer. The white layer may be formed by depositing a layer of metal, metal oxide, or other solid material using physical vapor deposition or other suitable deposition techniques and creating a translucent porous light-scattering layer from the deposited solid layer by annealing the deposited layer. Layer  30  may be an opaque layer such as a grayish or whitish layer of zinc oxide or other material with a thickness of 0.5 to 5 microns, 1-3 microns, or other suitable that ensures that a desired optical density (opacity) for layer  30  and therefore structures  24  is achieved. 
       FIG. 3  is a diagram showing how opaque masking structures  24  may be formed on the underside of a transparent structure such as button member  26 . 
     As shown in  FIG. 3 , deposition tool  40  may deposit a layer of material (layer  28 ′) on the underside of button member  26 . Deposition tool  40  may be a physical vapor deposition tool such as a sputtering tool or evaporation system. Layer  28 ′ may be a metal such as titanium, zirconium, zinc, or other metal, may be a metal oxide such as zirconium oxide or other metal oxide, or may be any other suitable layer of material that can be processed to form layer  28  of structures  24 . Layer  28 ′ may have a thickness of 2-5 microns, 1-10 microns, more than 0.5 microns, more than 2 microns, less than 20 microns, less than 10 microns, less than 6 microns, less than 4 microns, or other suitable thickness. 
     Following deposition of layer  28 ′, layer  28 ′ can be annealed using annealing tool  42 . Annealing tool  42  may have a heated chamber or other equipment for raising the temperature of member  26  and layer  28 ′ to an elevated temperature in the presence of a desired gaseous environment. As an example, annealing tool  42  may be used to anneal layer  28 ′ at a temperature of 800-1200° C., 900-1000° C., less than 1250° C., more than 700° C., or other suitable temperature for 1-60 minutes, fewer than 10 minutes, or more than 5 minutes, or other suitable duration. Annealing may be performed in air (which contains oxygen), oxygen, or other gaseous environments containing oxygen or other suitable reactant for reacting with layer  28 ′. 
     The annealing process transforms layer  28 ′ (e.g., a solid layer) to light-scattering layer  28  (e.g., a porous layer created by oxidizing layer  28 ′). During annealing of titanium, for example, titanium dioxide crystallization may create a porous titanium oxide layer in which pores within the layer serve as light scattering centers. The scattering of light in light-scattering layer  28  creates a desired color for structures  24  (e.g., white). The porous nature of the titanium dioxide in layer  28  may also allow atmospheric oxygen to penetrate into layer  28  when structures  24  are being used in a completed device. In the absence of atmospheric oxygen, the titanium dioxide in layer  28  might turn bluish upon exposure to ultraviolet light (e.g., due to the formation of Ti 3+  ions). When oxygen is able to penetrate into layer  28  through the pores of layer  28 , layer  28  will remain white. 
     Layer  28  may have a thickness of 25 microns, 10-30 microns, less than 25 microns, less than 15 microns, less than 10 microns, 2-5 microns, 1-10 microns, more than 0.5 microns, more than 2 microns, less than 20 microns, less than 6 microns, less than 4 microns, or other suitable thickness. Physical vapor deposition layers (before and after annealing) may be smoother than layers of printed ink and other opaque masking layers. By using a relatively thin and smooth layers in forming structures  24  (e.g., physical vapor deposition layers), operation of capacitive fingerprint sensor  34  ( FIG. 2 ) may be enhanced (e.g., noise may be reduced). Adhesion (e.g., adhesion by adhesive  32 ) may also be enhanced by forming structures  24  using physical vapor deposition. 
     Although layer  28  may have a desired appearance (e.g., white), layer  28  may be less opaque than desired. For example, layer  28  may have a translucent milky white appearance. To ensure that opaque masking structures  24  have a desired optical density, one or more additional layers of material may be used to coat layer  28 . For example, an additional layer of material such as layer  30  may be deposited on layer  28  using deposition tool  44  (e.g., a physical vapor deposition tool such as a sputtering tool or evaporation system). Layer  30 , may have a thickness of 1-3 microns, 2-5 microns, 1-10 microns, more than 0.5 microns, more than 1 micron, more than 2 microns, less than 3 microns, less than 5 microns, less than 10 microns, less than 6 microns, less than 4 microns, or other suitable thickness. Examples of materials that may be used for layer  30  include inorganic materials such as zirconium oxide (e.g., sputtered zirconium oxide) and other metal oxides. 
       FIG. 4  is a flow chart of illustrative steps involved in forming an electronic device with opaque masking structures  24 . 
     At step  50 , layer  28 ′ may be deposited on a structure such as button member  26 . For example, a layer of titanium, zirconium, zirconium oxide, zinc, other metals or metal oxides, or other materials may be deposited in a thin-film layer using deposition tool  40  (e.g., a physical vapor deposition tool). Layer  28 ′ may be a solid layer of inorganic material. 
     At step  52 , annealing tool  42  may be used to transform layer  28 ′ into a porous layer. Tool  42  may, for example, anneal layer  28 ′ in an environment containing oxygen, thereby oxidizing layer  28 ′ to create a layer (layer  28 ) that is porous. Porous layer  28  has light scattering centers (e.g., pores) that help scatter light and make layer  28  appear white (or other suitable color). 
     At step  54 , optical density can be enhanced by depositing a second layer of material such as layer  30  on layer  28 . Layer  30  may have a whitish or grayish appearance (as an example) and may be able to effectively block visible light even when layer  30  is thin (e.g., less than 25 microns, less than 5 microns, etc.). Layer  30  may be an inorganic layer or an organic layer. The use of a thin inorganic layer for layer  30  may help enhance fingerprint sensor performance. 
     Adhesive  32  may be used to attach fingerprint sensor  34  or other devices to opaque masking structures  24  (e.g., layer  28  and layer  30 ) at step  56 . Button member  26  and other structures may then be assembled to form device  10  (step  58 ). 
     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.

Metadata:
Filing Date: 20160601
Publication Date: 20191119
Grant Date: 20191119
Priority Date: 20160106
Inventors: MATSUYUKI, NAOTO
ROGERS, MATTHEW S.
Assignee: APPLE INC
CPC Classifications: [{"code": "G06K9/0002", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06V40/1329", "inventive": true, "first": true, "tree": "[]"}, {"code": "G06V40/1306", "inventive": true, "first": false, "tree": "[]"}, {"code": "G06V40/1306", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 68536413