WO2020055377A1

WO2020055377A1 - Covers for electronic devices

Info

Publication number: WO2020055377A1
Application number: PCT/US2018/050146
Authority: WO
Inventors: Kuan-Ting Wu; Ju-Hung Chen; Cheng-Feng Liao
Original assignee: Hewlett-Packard Development Company, L.P.
Priority date: 2018-09-10
Filing date: 2018-09-10
Publication date: 2020-03-19
Also published as: TWI722393B; TW202011788A

Abstract

The present disclosure is drawn to covers for electronic devices. In one example, a cover for an electronic device can include a metal support having an antenna window opening. The cover can also include an antenna window positioned at the antenna window opening. The antenna window can include multiple fused layers which individually include polymer particles fused together using a fusing agent.

Description

COVERS FOR ELECTRONIC DEVICES

BACKGROUND

[0001] The use of personal electronic devices of all types continues to increase. Cellular phones, including smartphones, have become nearly ubiquitous. Tablet computers have also become more widely used in recent years. Portable laptop computers continue to be used by many for personal, entertainment, and business purposes. Most of these devices have wireless connectivity. Various protocols for wireless connectivity are used, including wireless local area networking (Wi-Fi), Bluetooth®, and cellular networking protocols. These protocols differ in range and the type of data for which the protocols are used. However, these various modes of wireless connection functions by transmitting and receiving radio waves. Accordingly, wireless electronic devices typically have an antenna for transmitting and receiving these radio waves.

BRIEF DESCRIPTION OF THE DRAWING

[0002] FIG. 1 is a top plan view of an example cover for an electronic device in accordance with the present disclosure;

[0003] FIG. 2 is a top plan view of another example cover for an electronic device in accordance with the present disclosure;

[0004] FIG. 3 is a top plan view of yet another example cover for an electronic device in accordance with the present disclosure;

[0005] FIG. 4 is an exploded view of an example electronic device in accordance with the present disclosure; [0006] FIGs. 5-8 illustrate an example method of making an example antenna window in accordance with the present disclosure; and

[0007] FIG. 9 is a flow chart illustrating an example method of making a cover for an electronic device in accordance with the present disclosure.

DETAILED DESCRIPTION

[0008] The present disclosure describes metal supports for electronic devices with plastic antenna windows to allow transmitting of radio waves through the metal supports. In one example, a cover for an electronic device can include a metal support having an antenna window opening and an antenna window positioned in the antenna window opening. The antenna window can include multiple fused layers which individually include polymer particles fused together using a fusing agent. In further examples, the fusing agent can be an infrared radiation absorbing fusing agent, and the multiple fused layers can be fused by application of infrared energy to individual layers during a build of the antenna window. In other examples, the metal support can include aluminum, magnesium, titanium, lithium, niobium, stainless steel, or an alloy thereof. In still further examples, the polymer particles can include nylon 6, nylon 1 1 , nylon 12, polycarbonate, acrylonitrile butadiene styrene, thermoplastic polyurethane, amorphous polyamide, polymethylmethacrylate, ethylene-vinyl acetate, polyarylate, silicone rubber, copolymers of polycarbonate with acrylonitrile butadiene styrene, copolymers of polycarbonate with polyethylene terephthalate, or combinations thereof. In certain examples, the fusing agent can include glass fiber, titanium dioxide, clay, mica, talc, barium sulfate, calcium carbonate, a near-infrared absorbing dye, a near-infrared absorbing pigment, a conjugated polymer, a dispersant, or combinations thereof. In a particular example, the metal support and the antenna window can be coated to conceal the transition between the metal support and the antenna window.

[0009] The present disclosure also extends to electronic devices. In one example, an electronic device can include an antenna connected to a transmitter, receiver, or transceiver. The device can also include a cover including a metal support having an antenna window opening positioned over the antenna. An antenna window can be at the antenna window opening, and the antenna window can include multiple fused layers which individually include polymer particles fused together using a fusing agent. In further examples, the electronic device can be a laptop, a tablet, a smartphone, or a television. In certain examples, the metal support can include aluminum, magnesium, titanium, lithium, niobium, stainless steel, or an alloy thereof. In yet further examples, the polymer particles can include nylon 6, nylon 1 1 , nylon 12, polycarbonate, acrylonitrile butadiene styrene, thermoplastic polyurethane, amorphous polyamide,

polymethylmethacrylate, ethylene-vinyl acetate, polyarylate, silicone rubber, copolymers of polycarbonate with acrylonitrile butadiene styrene, copolymers of polycarbonate with polyethylene terephthalate, or combinations thereof. In other examples, the fusing agent can include glass fiber, titanium dioxide, clay, mica, talc, barium sulfate, calcium carbonate, a near-infrared absorbing dye, a near-infrared absorbing pigment, a conjugated polymer, a dispersant, or combinations thereof.

[0010] The present disclosure also extends to methods of making covers for electronic devices. In one example, a method of making a cover for an electronic device can include forming a metal support having an antenna window opening. An antenna window can be formed to associate with the antenna window opening. The antenna window can be formed by iteratively applying individual build material layers of polymer particles to a powder bed, selectively jetting a fusing agent onto individual build material layers based on a 3D object model, and exposing the powder bed to energy to selectively fuse the polymer particles in contact with the fusing agent at individual build material layers. The antenna window can be associated with the antenna window opening. In a particular example, associating the antenna window with the antenna window opening can include fitting the antenna window into the antenna window opening. In further examples, the method can include jetting a detailing agent on a second area of the individual build material layers. In yet another example, the method can include treating the metal support by micro-arc (MOA) oxidation, passivation, or anodization. [001 1] It is noted that when discussing describing the print media and methods described herein, these discussions can be considered applicable to other examples, whether or not they are explicitly discussed in the context of that example. Thus, for example, in discussing details about the media, such discussion also refers to the methods, and vice versa. It is also understood that terms used herein will take on their ordinary meaning in the relevant technical field unless specified otherwise. In some instances, there are terms defined more specifically throughout or included at the end of the present disclosure, and thus, these terms are supplemented as having a meaning described herein.

[0012] Covers for Electronic Devices

[0013] Metal is a popular material for making many electronic device covers. For example, metal supports can be used in laptops, smartphones, tablets, and others. Metallic covers on these devices are often a selling point because of the high strength and premium appearance of the metallic covers. Unfortunately, metal supports can also interfere with the transmission and receipt of radio waves used by these devices for wireless connectivity. Most laptops include an internal antenna to send and receive Wi-Fi signals. Smartphones often connect via Wi-Fi as well as cellular networks. Many of these devices also send and receive Bluetooth® signals to a variety of accessories such as keyboards, mice, headphones, and so on. Accordingly, the metal supports for these electronic devices can be modified to allow radio signals to reach the internal antenna of the devices.

[0014] In some examples, metal supports for electronic devices can include an antenna window opening positioned to allow radio waves to pass to and from an antenna of the electronic device. The antenna window opening can be covered by an antenna window, which can be a thin piece designed to fit over or in the antenna window opening. The antenna window can be made of a non-conductive material that permits radio waves. In some examples, the antenna window can be made of a plastic material.

[0015] In certain examples, metal supports for electronic devices can be treated with various surface treatments to enhance the appearance of the metal support, increase the durability of the metal support, or provide the metal support with corrosion resistance. These surface treatments can include anodization, passivation, and micro-arc oxidation. In some cases, plastic antenna windows can give rise to issues during these surface treatments. For example, applying an anodization treatment to an aluminum cover with a plastic antenna window can result in discoloring at the interface between the plastic antenna window and the aluminum. In another example, applying a micro-arc oxidation treatment to a metal support with a plastic window can result in ablation at the interface between the plastic part and the metal part due to the high temperature of the micro-arc oxidation process.

[0016] The present disclosure involves forming antenna windows through a three dimensional (3D) printing process. The process can involve fusing together polymer particles using a fusing agent. The antenna windows made in this way can be used with metal supports for electronic devices. Additionally, the antenna windows made in this way may not have the same issues with anodization and micro-arc oxidation treatments as other plastic antenna windows. In particular, in previous methods the antenna windows have been made by insert molding the antenna window with the metal support. The insert molding is performed before the anodizing or micro-arc oxidation treatment. If the anodizing process is performed before insert molding, then the anodized coating can be damaged by the insert molding process. Additionally, in the process of making magnesium alloy metal supports, it is more efficient to perform insert molding after molding the metal support and before the micro-arc oxidation process. The anodization and micro-arc oxidation processes also make the metal supports stiffer, which can cause defects during insert molding. However, when the antenna window is insert molded in this way then the issues mentioned above can occur during the anodization or micro-arc oxidation processes.

[0017] Metal supports can be used on a variety of electronic devices. For example, laptop computers, smartphones, tablet computers, and other electronic devices can include a metal support or chassis. In various examples, these metal supports can be formed by molding, casting, machining, bending, working, or another process. In one example, a metal support can be milled from a single block of metal. In other examples, the metal support can be made from multiple panels. For example, laptop covers sometimes include four separate pieces forming the cover of the laptop. The four separate pieces of the laptop cover are often designated as cover A (back cover of the monitor portion of the laptop), cover B (front cover of the monitor portion), cover C (top cover of the keyboard portion) and cover D (bottom cover of the keyboard portion). Covers can also be made for smartphones and tablet computers with a single metal piece or multiple metal panels.

[0018] As used herein,“cover” refers to the exterior shell of an electronic device. In other words, the cover contains the internal electronic components of the electronic device. The cover is an integral part of the electronic device. The term“cover” is not meant to refer to the type of removable protective cases that are often purchased separately from an electronic device (especially

smartphones and tablets) and placed around the exterior of the electronic device.

[0019] FIG. 1 shows an example cover 100 for an electronic device in accordance with the present disclosure. This cover includes a metal support 1 10 having an antenna window opening 120. An antenna window 130 is positioned at the antenna window opening. The antenna window is a plastic piece made from multiple fused layers of polymer particles fused together using a fusing agent. The antenna window in this example can be sized to fit into the antenna window opening. The metal support in this example is a cover panel for the back of the laptop monitor, sometimes referred to as“cover A.” This example can be used with an electronic device having an antenna located on the back of the monitor.

[0020] FIG. 2 shows another example of a cover 200 for an electronic device. This cover is a“cover C,” or the top cover for the keyboard portion of a laptop. The cover includes a metal support 210 made of a single piece of machined metal such as aluminum or magnesium alloy. The cover includes antenna window openings 220, 222 and plastic antenna windows 230, 232. As in the previous example, the antenna windows can be made from multiple fused layers of polymer particles fused together using a fusing agent. The metal support in this example also includes a number of other features, including hinge cut-outs 240, keyboard depression 250, key openings 252, speaker gratings 260, and track pad depression 270. This example cover can be used on an electronic device that has internal antennas located on the left and right side of the trackpad, where the antenna windows of the cover are located.

[0021] Yet another example cover 300 is shown in FIG. 3. This cover is a “cover D,” or the bottom cover of the keyboard portion of the laptop. This example cover can be used with laptops that have antennas on the bottom of the laptop. The cover in this example includes a metal support 310, antenna window openings 320, 322, and plastic antenna windows 330, 332. The antenna windows include multiple fused layers of polymer particles fused together using a fusing agent. The metal support also includes several screw holes 380 and hinge cut-outs 340.

[0022] Metal Supports

[0023] Various metals can be used to form the supports described herein. As used herein,“metal support” refers to a portion of the cover made from a metallic element or an alloy of multiple metallic elements. Non-limiting examples of the metal or metals used to make the cover can include aluminum, magnesium, titanium, lithium, niobium, stainless steel, and alloys thereof. In some examples, alloys of these metals can include additional metals, such as bismuth, copper, cadmium, iron, thorium, strontium, zirconium, manganese, nickel, lead, silver, chromium, silicon, tin, gadolinium, yttrium, calcium, antimony, zinc, cerium, lanthanum, or others. In a particular example, the substrate can be pure magnesium or an alloy including 99% magnesium or greater. In another particular example, the substrate can be made of an alloy including magnesium and aluminum. Examples of magnesium-aluminum alloys can include alloys made up of from 91 % to 99% magnesium by weight and from 1 % to 9% aluminum by weight, and alloys made up of 0.5% to 13% magnesium by weight and 87% to 99.5% aluminum by weight. Specific examples of magnesium-aluminum alloys can include AZ63, AZ81 , AZ91 , AM50, AM60, AZ31 , AZ31 B, AZ61 , AZ80, AE44, AJ62A, ALZ391 , AMCa602, LZ91 , and Magnox. Specific examples of aluminum-magnesium alloys can include 1050, 1060, 1 199, 2014, 2024, 2219, 3004, 4041 , 5005, 5010, 5019, 5024, 5026, 5050, 5052, 5056, 5059, 5083, 5086, 5154, 5182, 5252, 5254, 5356, 5454, 5456, 5457, 5557, 5652, 5657, 5754, 6005, 6005A, 6060, 6061 , 6063, 6066, 6070, 6082, 6105, 6162, 6262 ,6351 , 6463, 7005, 7022, 7068, 7072, 7075 ,7079, 7116, 7129, and/or7178. In a particular example, the substrate can be made from AZ31 or AZ91.

[0024] The antenna window openings can be made by machining, cutting through the metal support, or by molding or casting the metal support to include the antenna window openings. The placement of the antenna window openings can be selected based on the location of internal antennas in the electronic device for which the cover is designed. The antenna window openings can also be placed away from other design features, such as keyboards, trackpads, speakers, input/output ports, hinges, and so on. In certain examples, the internal antenna can be placed near other opening points in the metal support, such as openings for ports, optical drives, hinges, batteries, and so on. In these examples, antenna window openings may also be located near these other features to enhance the ability of the internal antenna to send and receive signals.

[0025] The size and shape of the antenna window opening can be based on the size and shape of the internal antenna in some examples. In certain examples, the antenna window opening can have roughly the same size as the internal antenna for which the window opening is designed. In other examples, the antenna window opening can be larger or smaller than the antenna. In specific examples, the antenna window opening can have a length or width that is from about 50% the length or width to about 200% the length or width, respectively, of the internal antenna. In further examples, the length or width of the antenna window opening can be from about 75% the length or width to about 150% the length or width of the internal antenna.

[0026] The plastic antenna window can be positioned at the antenna window opening. As used herein,“at the antenna window opening” can encompass being positioned over the antenna widow opening, under the antenna window opening, or fit into the antenna window opening. In certain examples, the antenna window can close the antenna window opening by covering the antenna window opening or by plugging the antenna window opening. Thus, the antenna window can eliminate the opening in the cover. In some examples, the antenna window can be designed to have a top surface that is flush with the top surface of the metal support. This can make the antenna window less noticeable to a user, and provide a cover with a flat continuous surface.

[0027] In further examples, the metal support and antenna window can be coated to conceal the transition between the metal support and the antenna window. Even if the antenna window is designed to fit tightly in the antenna window opening, a transition line may still be visible unless a coating is added to conceal this transition. In some examples, the coating can be a paint coating. In other examples, an overmolded decoration layer can be added to the cover to conceal the antenna window. Overmolded decoration layers can include a layer of plastic, such as acrylonitrile butadiene styrene (ABS), polycarbonate (PC), polyamide (PA), polymethyl methacrylate (PMMA), styrene ethylene butadiene styrene (SEBS), polyphenylene sulfide (PPS), polybutylene terephthalate (PBT), polyphenylene ether (PPE), polyphenylene oxide (PPO), or combinations thereof. In addition to the plastic material, the overmolded decoration layer can include ink patterns and/or non-conductive vacuum metallized (NCVM) patterns.

[0028] The antenna window can be designed to attach to the metal support in a variety of ways. In some examples, the antenna window or the metal support can include clips for holding the antenna window in place at the antenna window opening. In other examples, the antenna window can be pressure-fit into the antenna window opening. In still further examples, the antenna window can be bonded to the metal support using thermal bonding or an adhesive. Non-limiting examples of adhesives for attaching the antenna window can include epoxies, cyanoacrylates, ultraviolet curing adhesives, ethylene vinyl acetate copolymers, ethylene ethyl acrylate copolymers, ionomers, poly(ethyl acrylate), phenoxy resins, polyamides, polyesters, polyvinyl acetate, polyvinyl butyral, polyvinyl ethers, and others.

[0029] Electronic Devices

[0030] As mentioned above, electronic devices incorporating the covers described herein can include a variety of devices that have internal antennas for sending and/or receiving radio signals. Examples of these electronic devices can include laptops, tablet computers, smartphones, televisions, and others. FIG. 4 shows one example electronic device 400 that is a laptop. The laptop is shown in an exploded view, with a top cover (cover C) 410 and bottom cover (cover D) 412. The top and bottom covers are designed to contain internal electronics 490 including internal antennas 492, 494. The top cover includes two antenna window openings 420, 422 that are positioned to be over the internal antennas when the laptop is assembled. Two antenna windows 430, 432 can fit into the antenna window openings. [0031 ] Antenna Windows

[0032] As mentioned above, the antenna windows can include multiple fused layers that individually include polymer particles fused together using a fusing agent. This structure can be produced by a 3D printing process. In an example of the 3D printing process, a thin layer of polymer powder can be spread on a bed to form a powder bed. A printing head, such as an inkjet print head, can then be used to print a fusing fluid including a fusing agent over portions of the powder bed corresponding to a thin layer of the three dimensional object to be formed. Then the bed can be exposed to a light source, e.g., typically the entire bed. The fusing agent can absorb more energy from the light than the unprinted powder. The absorbed light energy is converted to thermal energy, causing the printed portions of the powder to melt and coalesce. This forms a solid layer. After the first layer is formed, a new thin layer of polymer powder is spread over the powder bed and the process is repeated to form additional layers until a complete 3D part is printed.

[0033] In some examples, a detailing fluid can be used together with the fusing fluid. The detailing fluid can be a fluid that reduces the temperature of the polymer powder on which the detailing fluid is printed. In certain examples, the detailing fluid can include a solvent that evaporates from the polymer powder to evaporatively cool the polymer powder. The detailing fluid can be printed in areas of the powder bed where fusing is not desired. In particular examples, the detailing fluid can be printed along the edges of areas where the fusing fluid is printed. This can give the fused layer a clean, defined edge where the fused polymer particles end and the adjacent polymer particles remain unfused.

[0034] One example illustrating the use of a material set according to the present technology is shown in FIGS. 5-8. FIG. 5 shows a layer 500 of polymer powder particles 510. A fusing fluid 520 including a viscosity reducing agent is dispensed onto a first portion 530 of the layer. A second portion 540 of the layer is not printed with the fusing fluid.

[0035] FIG. 6 shows the layer 500 of polymer powder particles 510 after the fusing fluid 520 has been printed onto the first portion 530 of the layer. A detailing fluid 560 is printed onto the second portion 540 of the layer.

[0036] FIG. 7 shows the layer 500 of polymer powder particles 510 after the fusing fluid 520 has been printed onto the first portion 530 and detailing fluid 560 has been printed onto the second portion 540.

[0037] FIG. 8 shows the layer 500 of polymer powder particles 510 after being fused by exposure to a light source. The polymer powder particles in the first portion 530 have fused together to form a matrix 570 of fused polymer particles. The polymer particles in the second portion 540 which were printed with the detailing fluid 560 remain as separate particles. This process can be repeated with additional layers of powder to form a 3D printed antenna window.

[0038] In other examples, the layer can be exposed to the light after the fusing fluid is printed as shown in FIG. 5, but without printing a detailing fluid on the layer. This can also result in a fused portion where the fusing fluid is printed and unfused particles in a portion where the fusing fluid was not printed.

However, using the detailing fluid in conjunction with the fusing fluid can in some examples increase the sharpness of the transition between the fused portion and the unfused particles.

[0039] Antenna windows made using this process can have a unique structure that is different from antenna windows produced by other methods. In some previous methods, antenna windows have been made by insert molding the antenna window with the metal support. However, the antenna windows produced using the 3D printing methods described herein can be made up of multiple fused layers that individually include polymer particles fused together using a fusing agent. When the layer of polymer particles printed with a fusing agent are fused together, the particles can melt together and form a substantially solid layer. However, the fusing agent remains in the material. Accordingly, the final structure of the antenna window includes the fusing agent located at interfaces where the polymer particles contacted one another during fusing. In some cases the fusing agent may mix somewhat with the polymer during fusing, but the fusing agent can be more concentrated at the interfaces between the polymer particles. Thus, the antenna windows produced using the methods described herein can have a unique structure with the fusing agent distributed throughout the material, concentrated at interfaces between fused particles.

[0040] Methods of Making Covers for Electronic Devices

[0041] The present disclosure also extends to methods of making covers for electronic devices, which can incorporate the 3D printing methods described above. FIG. 9 is a flowchart illustrating one example method 900 of making a cover for an electronic device. The method includes forming 910 a metal support having an antenna window opening, forming 920 an antenna window to associate with the antenna window opening, and associating 930 the antenna window with the antenna window opening. Forming the antenna window can include iteratively applying individual build material layers of polymer particles to a powder bed; and based on a 3D object model, selectively jetting a fusing agent onto individual build material layers. Additionally, forming the antenna window can include exposing the powder bed to energy to selectively fuse the polymer particles in contact with the fusing agent at individual build material layers; and

[0042] Forming the metal support can be done using any of the techniques mentioned above, such as machining, milling, bending, casting, molding, and so on. Forming the antenna windows can be done using the 3D printing methods described above.

[0043] The 3D printing process can use a powder bed. For layers of the printed antenna window, the process can include spreading a layer of loose polymer particles onto the powder bed and then printing the fusing fluid, followed by fusing the particles printed with the fusing fluid. At the beginning of the process, the powder bed can be empty because no polymer particles have been spread at that point. For the first layer, the polymer particles can be spread onto an empty build platform. The build platform can be a flat surface made of a material sufficient to withstand the heating conditions of the 3D printing process, such as a metal. Thus,“applying individual build material layers of polymer particles to a powder bed” includes spreading polymer particles onto the empty build platform for the first layer. A portion of the polymer particles are then printed with the fusing agent and fused to form the first layer of the antenna window. The unfused polymer particles remain in their place as loose particles. For the second layer, a new layer of loose polymer particles is spread over the top of the first layer. The second layer of particles is spread over both the fused particles making up the first layer of the antenna window, and the unfused particles in the remainder of the powder bed. Thus,“applying individual build material layers of polymer particles to a powder bed” includes spreading subsequent layers of particles over the loose, unfused particles below and the fused particles making up the lower layer of the antenna window. In some examples, the build platform can be configured to lower itself by a distance equivalent to the thickness of a single layer to make room for the next layer of loose polymer particles. [0044] Polymer Powders

[0045] In certain examples, the polymer particles can have a variety of shapes, such as substantially spherical particles or irregularly-shaped particles. In some examples, the polymer powder can be capable of being formed into 3D printed parts with a resolution of about 20 pm to about 100 pm, about 30 pm to about 90 pm, or about 40 pm to about 80 pm. As used herein,“resolution” refers to the size of the smallest feature that can be formed on a 3D printed part. The polymer powder can form layers from about 20 pm to about 100 pm thick, allowing the fused layers of the printed part to have roughly the same thickness. This can provide a resolution in the z-axis direction of about 20 pm to about 100 pm. The polymer powder can also have a sufficiently small particle size and sufficiently regular particle shape to provide about 20 pm to about 100 pm resolution along the x-axis and y-axis. Other resolutions along these axes can be from about 30 miti to about 90 miti, or from 40 miti to about 80 miti.

[0046] The thermoplastic polymer powder can have a melting or softening point from about 70°C to about 350°C. In further examples, the polymer can have a melting or softening point from about 150°C to about 200°C. A variety of thermoplastic polymers with melting points or softening points in these ranges can be used. For example, the polymer powder can be selected from the group consisting of nylon 6 powder, nylon 9 powder, nylon 1 1 powder, nylon 12 powder, nylon 66 powder, nylon 612 powder, polyethylene powder, thermoplastic polyurethane powder, acrylonitrile butadiene styrene powder, amorphous polyamide powder, polymethylmethacrylate powder, ethylene-vinyl acetate powder, polyarylate powder, silicone rubber, polypropylene powder, polyester powder, polycarbonate powder, copolymers of polycarbonate with acrylonitrile butadiene styrene, copolymers of polycarbonate with polyethylene terephthalate polyether ketone powder, polyacrylate powder, polystyrene powder, and mixtures thereof. In a specific example, the polymer powder can be nylon 12, which can have a melting point from about 175°C to about 200°C. In another specific example, the polymer powder can be thermoplastic polyurethane.

[0047] The thermoplastic polymer particles can also in some cases be blended with a filler. The filler can include inorganic particles such as alumina, silica, or combinations thereof. When the thermoplastic polymer particles fuse together, the filler particles can become embedded in the polymer, forming a composite material. In some examples, the filler can include a free-flow agent, anti-caking agent, or the like. Such agents can prevent packing of the powder particles, coat the powder particles and smooth edges to reduce inter-particle friction, and/or absorb moisture. In some examples, a weight ratio of

thermoplastic polymer particles to filler particles can be from 10:1 to 1 :2 or from 5:1 to 1 :1. [0048] Fusing Fluids

[0049] In further examples, the fusing fluid can include a fusing agent that is capable of absorbing electromagnetic radiation to produce heat. The fusing agent can be colored or colorless. In various examples, the fusing agent can be glass fiber, titanium dioxide, clay, mica, talc, barium sulfate, calcium carbonate, a near-infrared absorbing dye, a near-infrared absorbing pigment, a dispersant, a conjugated polymer, a dispersant, or combinations thereof. Examples of near-infrared absorbing dyes include aminium dyes, tetraaryldiamine dyes, cyanine dyes, pthalocyanine dyes, dithiolene dyes, and others. In further examples, the fusing agent can be a near-infrared absorbing conjugated polymer such as poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS), a polythiophene, poly(p-phenylene sulfide), a polyaniline, a poly(pyrrole), a poly(acetylene), poly(p-phenylene vinylene), polyparaphenylene, or

combinations thereof. As used herein,“conjugated” refers to alternating double and single bonds between atoms in a molecule. Thus,“conjugated polymer” refers to a polymer that has a backbone with alternating double and single bonds. In many cases, the fusing agent can have a peak absorption wavelength in the range of 800 nm to 1400 nm.

[0050] A variety of near-infrared pigments can also be used. Non-limiting examples can include phosphates having a variety of counterions such as copper, zinc, iron, magnesium, calcium, strontium, the like, and combinations thereof. Non-limiting specific examples of phosphates can include M2P2O7, M₄P₂0₉, M5P2O10, M₃(P0₄)₂, M(P0₃)₂, M₂P₄0i2, and combinations thereof, where

M represents a counterion having an oxidation state of +2, such as those listed above or a combination thereof. For example, M2P2O7 can include compounds such as CU2P2O7, Cu/MgP₂0₇, Cu/ZnP₂0₇, or any other suitable combination of counterions. It is noted that the phosphates described herein are not limited to counterions having a +2 oxidation state. Other phosphate counterions can also be used to prepare other suitable near-infrared pigments.

[0051] Additional near-infrared pigments can include silicates. Silicates can have the same or similar counterions as phosphates. One non-limiting example can include M₂Si0₄, M₂Si₂0₆, and other silicates where M is a counterion having an oxidation state of +2. For example, the silicate M₂Si₂0₆ can include Mg₂Si₂0₆, Mg/CaSi₂0₆, MgCuSi₂0₆, Cu₂Si₂0₆, Cu/ZnSi₂0₆, or other suitable combination of counterions. It is noted that the silicates described herein are not limited to counterions having a +2 oxidation state. Other silicate counterions can also be used to prepare other suitable near-infrared pigments.

[0052] A dispersant can be included in some examples. Dispersants can help disperse the radiation absorbing pigments described above. In some examples, the dispersant itself can also absorb radiation and act as a fusing agent. Non-limiting examples of dispersants that can be included as a fusing agent, either alone or together with a pigment, can include polyoxyethylene glycol octylphenol ethers, ethoxylated aliphatic alcohols, carboxylic esters, polyethylene glycol ester, anhydrosorbitol ester, carboxylic amide, polyoxyethylene fatty acid amide, poly (ethylene glycol) p-isooctyl-phenyl ether, sodium polyacrylate, and combinations thereof.

[0053] The amount of fusing agent in the second fusing fluid can vary depending on the type of fusing agent. In some examples, the concentration of fusing agent in the fusing fluid can be from about 0.1 wt% to about 20 wt%. In one example, the concentration of fusing agent in the fusing fluid can be from about 0.1 wt% to about 15 wt%. In another example, the concentration can be from about 0.1 wt% to about 8 wt%. In yet another example, the concentration can be from about 0.5 wt% to about 2 wt%. In a particular example, the concentration can be from about 0.5 wt% to about 1.2 wt%. In one example, the fusing agent can have a concentration in the fusing fluid such that after the fusing fluid is printed onto the polymer powder, the amount of fusing agent in the polymer powder can be from about 0.0003 wt% to about 10 wt%, or from about 0.005 wt% to about 5 wt%, with respect to the weight of the polymer powder. [0054] Detailing Fluids

[0055] The detailing fluid can include a detailing agent capable of cooling the polymer powder in portions of the powder bed onto which the detailing fluid is printed. In some examples, the detailing fluid can be printed around the edges of the portion of the powder that is printed with the fusing fluid. The detailing fluid can increase selectivity between the fused and unfused portions of the powder bed by reducing the temperature of the powder around the edges of the portion to be fused. [0056] In some examples, the detailing agent can be a solvent that evaporates at the temperature of the powder bed. In some cases the powder bed can be preheated to a preheat temperature within about 10 °C to about 70 °C of the fusing temperature of the polymer powder. Depending on the type of polymer powder used, the preheat temperature can be in the range of about 90 °C to about 200 °C or more. Thus, the detailing agent can be a solvent that evaporates when it comes into contact with the powder bed at the preheat temperature, thereby cooling the printed portion of the powder bed through evaporative cooling. In certain examples, the detailing agent can include water, co-solvents, or combinations thereof. Non-limiting examples of co-solvents for use in the detailing fluid can include xylene, methyl isobutyl ketone,

3-methoxy-3-methyl-1 -butyl acetate, ethyl acetate, butyl acetate, propylene glycol monomethyl ether, ethylene glycol mono tert-butyl Ether, dipropylene glycol methyl ether, diethylene glycol butyl ether, ethylene glycol monobutyl ether, 3-Methoxy-3-Methyl-1 -butanol, isobutyl alcohol, 1 ,4-butanediol,

N,N-dimethyl acetamide, and combinations thereof. In further examples, the detailing agent can be substantially devoid of thermal fusing agents. That is, in some examples, the detailing agent can be substantially devoid of ingredients that absorb enough energy from the light source to cause the powder to fuse. In certain examples, the detailing fluid can include colorants such as dyes or pigments, but in small enough amounts that the colorants do not cause the powder printed with the detailing fluid to fuse when exposed to the light source.

[0057] The components of the above described fluids, e.g., fusing fluids and detailing fluids, can be selected to give the respective fluids good fluid jetting performance and the ability to fuse the polymer bed material. Thus, these fluids can include a liquid vehicle. In some examples, the liquid vehicle formulation can include a co-solvent or co-solvents present in total at from about 1 wt% to about 50 wt%, depending on the jetting architecture. Further, a non-ionic, cationic, and/or anionic surfactant can be present, ranging from about 0.01 wt% to about 5 wt%. In one example, the surfactant can be present in an amount from about 1 wt% to about 5 wt%. The liquid vehicle can include dispersants in an amount from about 0.5 wt% to about 3 wt%. The balance of the formulation can be purified water, and/or other vehicle components such as biocides, viscosity modifiers, materials for pH adjustment, sequestering agents, preservatives, and the like. In one example, the liquid vehicle can be predominantly water.

[0058] In some examples, a water-dispersible or water-soluble fusing agent can be used with an aqueous vehicle. Because the fusing agent is dispersible or soluble in water, an organic co-solvent may not be present, as it may not be included to solubilize the fusing agent. Therefore, in some examples the fluids can be substantially free of organic solvent, e.g., predominantly water. However, in other examples a co-solvent can be used to help disperse other dyes or pigments, or enhance the jetting properties of the respective fluids. In still further examples, a non-aqueous vehicle can be used with an organic-soluble or organic-dispersible fusing agent.

[0059] In certain examples, a high boiling point co-solvent can be included in the various fluids. The high boiling point co-solvent can be an organic co-solvent that boils at a temperature higher than the temperature of the powder bed during printing. In some examples, the high boiling point co-solvent can have a boiling point above about 250 °C. In still further examples, the high boiling point co-solvent can be present in the various fluids at a concentration from about 1 wt% to about 4 wt%.

[0060] Classes of co-solvents that can be used can include organic co-solvents including aliphatic alcohols, aromatic alcohols, diols, glycol ethers, polyglycol ethers, caprolactams, formamides, acetamides, and long chain alcohols. Examples of such compounds include 1 -aliphatic alcohols, secondary aliphatic alcohols, 1 ,2-alcohols, 1 ,3-alcohols, 1 ,5-alcohols, ethylene glycol alkyl ethers, propylene glycol alkyl ethers, higher homologs (C₆-Ci₂) of polyethylene glycol alkyl ethers, N-alkyl caprolactams, unsubstituted caprolactams, both substituted and unsubstituted formamides, both substituted and unsubstituted acetamides, and the like. Specific examples of solvents that can be used include, but are not limited to, 2-pyrrolidinone, N-methylpyrrolidone,

2-hydroxyethyl-2-pyrrolidone, 2-methyl-1 ,3-propanediol, tetraethylene glycol, 1 ,6-hexanediol, 1 ,5-hexanediol and 1 ,5-pentanediol. [0061] Regarding the surfactant that may be present, a surfactant or surfactants can be used, such as alkyl polyethylene oxides, alkyl phenyl polyethylene oxides, polyethylene oxide block copolymers, acetylenic

polyethylene oxides, polyethylene oxide (di)esters, polyethylene oxide amines, protonated polyethylene oxide amines, protonated polyethylene oxide amides, dimethicone copolyols, substituted amine oxides, and the like. The amount of surfactant added to the formulation of this disclosure may range from 0.01 wt% to 20 wt%. Suitable surfactants can include, but are not limited to, liponic esters such as Tergitol™ 15-S-12, Tergitol™ 15-S-7 available from Dow Chemical Company, LEG-1 and LEG-7; Triton™ X-100; Triton™ X-405 available from Dow Chemical Company ; and sodium dodecylsulfate.

[0062] Consistent with the formulations of this disclosure, as mentioned, various other additives can be employed to enhance certain properties of the fluid compositions for specific applications. Examples of these additives are those added to inhibit the growth of harmful microorganisms. These additives may be biocides, fungicides, and other microbial agents, which can be used in ink various formulations. Examples of suitable microbial agents include, but are not limited to, NUOSEPT® (Nudex, Inc.), UCARCIDE™ (Union carbide Corp.), VANCIDE® (R.T. Vanderbilt Co.), PROXEL® (ICI America), and combinations thereof.

[0063] Sequestering agents, such as EDTA (ethylene diamine tetra acetic acid), may be included to eliminate the deleterious effects of heavy metal impurities, and buffer solutions may be used to control the pH of the fluid. From 0.01 wt% to 2 wt%, for example, can be used. Viscosity modifiers and buffers may also be present, as well as other additives to modify properties of the fluid as desired. Such additives can be present at from 0.01 wt% to 20 wt%.

[0064] 3D Printing Systems

[0065] Systems for performing the 3D printing process described above can include a powder bed, inkjet print heads to print fusing fluid and detailing fluid onto the powder bed, and an energy source to fuse the polymer particles printed with the fusing fluid. To achieve good selectivity between the fused and unfused portions of the powder bed, the fusing agent can absorb enough energy to boost the temperature of the printed portion above the fusing temperature of the polymer particles. Thus, the portions of the powder bed printed with the fusing agent can be fused by the energy source. In some cases, the energy source can be a lamp such as an infrared lamp. The detailing fluid can be printed around the edges of the portion to be fused, cooling the powder around the edges and further increasing the temperature difference between the portion to be fused and the surrounding portions of the powder bed. In some examples, the 3-dimensional printing system can include preheaters for preheating the polymer powder to a temperature near the fusing temperature. In one example, the system can include a print bed heater to heat the print bed during printing. The preheat temperature used can depend on the type of polymer used. In some examples, the print bed heater can heat the print bed to a temperature from 50 °C to 250 °C. The system can also include a supply bed, where polymer particles can be stored before being spread in a layer onto the print bed. The supply bed can have a supply bed heater. In some examples, the supply bed heater can heat the supply bed to a temperature from 80 °C to 140 °C.

[0066] Suitable fusing lamps for use in the 3-dimensional printing system can include commercially available infrared lamps and halogen lamps. The fusing lamp can be a stationary lamp or a moving lamp. For example, the lamp can be mounted on a track to move horizontally across the powder bed. Such a fusing lamp can make multiple passes over the bed depending on the amount of exposure needed to fuse the various printed layer. The fusing lamp can be configured to irradiate the entire powder bed with a substantially uniform amount of energy. This can selectively fuse the portions printed with the fusing agent while leaving the unprinted portions of the polymer powder below the fusing temperature.

[0067] In one example, the fusing lamp can be matched with the fusing agents so that the source emits wavelengths of light that match the peak absorption wavelengths of the fusing agents. A fusing agent with a narrow peak at a particular near-infrared wavelength can be used with an electromagnetic radiation fusing source that emits a narrow range of wavelengths at

approximately the peak wavelength of the fusing agent. Similarly, a fusing agent that absorbs a broad range of near-infrared wavelengths can be used with an electromagnetic radiation fusing source that emits a broad range of wavelengths. Matching the fusing agent and the electromagnetic radiation fusing source in this way can increase the efficiency of fusing the polymer particles with the fusing agent printed thereon, while the unprinted polymer particles do not absorb as much light and remain at a lower temperature.

[0068] Depending on the amount of fusing agent present in the polymer powder, the absorbance of the fusing agent, the preheat temperature, and the fusing temperature of the polymer, an appropriate amount of irradiation can be supplied from the electromagnetic radiation fusing source or fusing lamp. In some examples, the fusing lamp can irradiate the various layer from about 0.1 to about 10 seconds per pass. In further examples, the fusing lamp can move across the powder bed at a rate of 1 inch per second to 60 inches per second to fuse the various layers. In still further examples, the fusing lamp can move across the powder bed at a rate of 5 inches per second to 20 inches per second.

[0069] Surface Treatments

[0070] In certain examples, the method of making a cover for an electronic device can also include treating the metal support by micro-arc oxidation, passivation, or anodization. Micro-arc oxidation is also known as plasma electrolytic oxidation. This process involves immersing the metal support in an electrolyte and creating small electric discharges on the surface of the substrate. In one example, a high-voltage alternating current can be applied to the metal support to create plasma on the surface of the metal support. In this process, the metal support can act as one electrode immersed in the electrolyte solution, and the counter electrode can be any other electrode that is also in contact with the electrolyte. In some examples, the counter electrode can be an inert metal such as stainless steel. In certain examples, the bath holding the electrolyte solution can be conductive and the bath itself can be used as the counter electrode. A high direct current or alternating voltage can be applied to the substrate and the counter electrode. In some examples, the voltage can be 200 V or higher, such as about 200 V to about 500 V, or about 200 V to about 300 V. This oxidizes the surface to form an oxide layer from the metal. The oxidation can extend below the surface to form thick layers, as thick as 25 micrometers or more. In some examples the oxide layer can have a thickness from about 1 micrometer to about 25 micrometers, from about 1 micrometer to about 20 micrometers, or from about 2 micrometers to about 15 micrometers. The oxide layer can enhance the mechanical, wear, thermal, dielectric, and corrosion properties of the metal support. The electrolyte solution can include a variety of electrolytes, such as a solution of potassium hydroxide.

[0071] In some examples, the metal support can be treated with micro-arc oxidation before the 3D printed antenna window is associated with the antenna window opening. The micro-arc oxidation process can involve immersing the metal support in an alkaline chemical bath and running an electrical current through the metal support. This can form electrical arcs that oxidize the metal support surface. The arcs can also create very high local temperatures, up to 8, 000 °C. Thus, the 3D printed antenna window can be associated with the antenna window opening after the micro-arc oxidation treatment to avoid these extreme conditions.

[0072] In further examples, the metal support can be treated with a passivation treatment. In some examples, the passivation treatment can include dissolving a passivating compound in a solution and immersing the metal support in the solution to form a layer of the passivating compound on the metal support. Examples of passivation treatments can include chromate conversion coating, phosphate conversion coating, molybdate conversion coating, vanadate conversion coating, stannate conversion coating, and others.

[0073] In still further examples, the metal support can be treated by anodization. Anodization is a particular type of passivation process. When anodizing aluminum, for example, the aluminum metal is used as an anode submerged in an electrolyte solution and an electric current is passed through the solution. Oxygen is released at the anode surface, forming a buildup of aluminum oxide. Dyes can also be added during this process, which can penetrate beneath the surface of the aluminum oxide to make a durable colored surface. In some examples, the 3D printed antenna window can be associated with the antenna window opening after the anodization treatment to avoid unwanted reaction with the electrolyte solution.

[0074] Definitions

[0075] It is noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the content clearly dictates otherwise.

[0076] As used herein, the term“about” is used to provide flexibility to a numerical range endpoint by providing that a given value may be“a little above” or“a little below” the endpoint. The degree of flexibility of this term can be dictated by the particular variable and can be determined based on experience and the associated description herein.

[0077] As used herein, a plurality of items, structural elements, compositional elements, and/or materials may be presented in a common list for convenience. However, these lists should be construed as though the various members of the list is individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary.

[0078] Concentrations, dimensions, amounts, and other numerical data may be presented herein in a range format. It is to be understood that such range format is used merely for convenience and brevity and should be interpreted flexibly to include the numerical values explicitly recited as the limits of the range, and also to include all the individual numerical values or sub-ranges

encompassed within that range as if the various numerical value and sub-range is explicitly recited. For example, a weight ratio range of about 1 wt% to about 20 wt% should be interpreted to include the explicitly recited limits of 1 wt% and about 20 wt%, and also to include individual weights such as 2 wt%, 1 1 wt%, 14 wt%, and sub-ranges such as 10 wt% to 20 wt%, 5 wt% to 15 wt%, etc.

[0079] The following illustrates an example of the present disclosure. However, it is to be understood that the following is illustrative of the application of the principles of the present disclosure. Numerous modifications and alternative compositions, methods, and systems may be devised without departing from the spirit and scope of the present disclosure. The appended claims are intended to cover such modifications and arrangements.

EXAMPLE

[0080] An example metal laptop cover with a window is formed from alloy AZ31 , which is 3 wt% aluminum, 1 wt% zinc, and 96 wt% magnesium. The metal support is formed with an antenna window opening through the metal support. The metal support is treated with micro-arc oxidation to form a protective oxide layer on the surface of the metal panel.

[0081] An antenna window is formed using the following 3D printing process. An HP JET FUSION® 3D printer (HP Hewlett Packard Group LLC, Texas) is loaded with nylon 6 polymer powder. The 3D printer spreads layers of the polymer powder on a powder bed and then jets a fusing fluid and detailing fluid onto the layers using inkjet print heads. The 3D printer includes a halogen fusing lamp mounted to move across the powder bed to fuse the various layers after the fusing fluid and detailing fluid are jetted.

[0082] The 3D printed antenna window is then placed in the antenna window opening of the metal support. The metal support can then be attached to an electronic device with the antenna window near an internal antenna in the electronic device.

[0083] What has been described and illustrated herein is an example of the disclosure along with some of its variations. The terms, descriptions, and figures used herein are set forth by way of illustration and are not meant as limitations. Many variations are possible within the spirit and scope of the disclosure, which is intended to be defined by the following claims - and their equivalents - in which all terms are meant in their broadest reasonable sense unless otherwise indicated.

Claims

What is claimed is: 1. A cover for an electronic device comprising:

a metal support having an antenna window opening; and

an antenna window positioned at the antenna window opening, wherein the antenna window comprises multiple fused layers which individually include polymer particles fused together using a fusing agent.

2. The cover of claim 1 , wherein the fusing agent is an infrared radiation absorbing fusing agent, and the multiple fused layers are fused by application of infrared energy to individual layers during a build of the antenna window.

3. The cover of claim 1 , wherein the metal support comprises aluminum, magnesium, titanium, lithium, niobium, stainless steel, or an alloy thereof.

4. The cover of claim 1 , wherein the polymer particles comprise nylon 6, nylon 1 1 , nylon 12, polycarbonate, acrylonitrile butadiene styrene, thermoplastic polyurethane, amorphous polyamide, polymethylmethacrylate, ethylene-vinyl acetate, polyarylate, silicone rubber, copolymers of polycarbonate with acrylonitrile butadiene styrene, copolymers of polycarbonate with polyethylene terephthalate, or combinations thereof.

5. The cover of claim 1 , wherein the fusing agent comprises glass fiber, titanium dioxide, clay, mica, talc, barium sulfate, calcium carbonate, a near-infrared absorbing dye, a near-infrared absorbing pigment, a conjugated polymer, a dispersant, or combinations thereof.

6. The cover of claim 1 , wherein the metal support and the antenna window are coated to conceal the transition between the metal support and the antenna window.

7. An electronic device comprising:

an antenna connected to a transmitter, receiver, or transceiver;

a cover including a metal support having an antenna window opening positioned over the antenna; and

an antenna window at the antenna window opening, wherein the antenna window comprises multiple fused layers which individually include polymer particles fused together using a fusing agent.

8. The electronic device of claim 7, wherein the electronic device is a laptop, a tablet, a smartphone, or a television.

9. The electronic device of claim 7, wherein the metal support comprises aluminum, magnesium, titanium, lithium, niobium, stainless steel, or an alloy thereof.

10. The electronic device of claim 7, wherein the polymer particles comprise nylon 6, nylon 1 1 , nylon 12, polycarbonate, acrylonitrile butadiene styrene, thermoplastic polyurethane, amorphous polyamide,

polymethylmethacrylate, ethylene-vinyl acetate, polyarylate, silicone rubber, copolymers of polycarbonate with acrylonitrile butadiene styrene, copolymers of polycarbonate with polyethylene terephthalate, or combinations thereof.

1 1. The electronic device of claim 7, wherein the fusing agent comprises glass fiber, titanium dioxide, clay, mica, talc, barium sulfate, calcium carbonate, a near-infrared absorbing dye, a near-infrared absorbing pigment, a conjugated polymer, a dispersant, or combinations thereof.

12. A method of making a cover for an electronic device comprising: forming a metal support having an antenna window opening;

forming an antenna window to associate with the antenna window opening by: iteratively applying individual build material layers of polymer particles to a powder bed;

based on a 3D object model, selectively jetting a fusing agent onto individual build material layers, and

exposing the powder bed to energy to selectively fuse the polymer particles in contact with the fusing agent at individual build material layers,

associating the antenna window with the antenna window opening.

13. The method of claim 12, wherein associating includes fitting the antenna window into the antenna window opening.

14. The method of claim 12, further comprising jetting a detailing agent on a second area of the individual build material layers.

15. The method of claim 12, further comprising treating the metal support by micro-arc oxidation, passivation, or anodization.