WO2016003421A1

WO2016003421A1 - Computer device casing

Info

Publication number: WO2016003421A1
Application number: PCT/US2014/044906
Authority: WO
Inventors: Chi-Hao Chang; Chung-Hung Huang; Kuan-Ting Wu
Original assignee: Hewlett-Packard Development Company, L.P.
Priority date: 2014-06-30
Filing date: 2014-06-30
Publication date: 2016-01-07

Abstract

A computer device casing in accordance with one example includes a substrate, an electrically conductive coating on the substrate and an Electrophoretic Deposition (ED) layer or Anodized layer on the electrically conductive coating.

Description

COMPUTER DEVICE CASING BACKGROUND

[0001] Electronic devices, such as mobile phones, smart phones, tablet computers, laptop computers may have a casing. A surface of the casing may be treated by a process such as Electrophoretic Deposition (ED) or Anodizing.

[0002] Electrophoretic Deposition (ED) is a process in which a substrate is placed in a fluid and a potential difference is applied which causes charged polymer-based particles suspended in the fluid to be deposited on the substrate. ED is different to electroplating in that in ED the charged particles are solid polymer-based particles suspended in a fluid, whereas in electroplating the particles are ions. In ED the particles may for example be 10 nm to 2 μπΊ in size. The deposition of charged polymeric species of ED may be much quicker than electroplating deposition. Cationic or anionic polymeric species can be selected as ED chemicals.

[0003] Anodizing is a process used to generate an oxide layer on a metal part, or to increase the thickness of a natural oxide layer on a metal part. Anodizing typically involves applying an electric potential difference while the metal part is placed in an acidic or alkaline electrolyte. The electric potential causes an oxidized later to be built up to a greater thickness than would be achieved by simple exposure of the metal part to the environment.

BRIEF DESCRIPTION OF THE DRAWINGS

[0004] Examples will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which:

Figure 1 is a cross section of an example computer device casing according to the present disclosure;

Figure 2 is a cross section of another example computer device casing according to the present disclosure;

Figure 3 is a cross section of another example computer device casing according to the present disclosure;

Figure 4 is a cross section of another example computer device casing according to the present disclosure;

Figure 5 is a cross section of another example computer device casing according to the present disclosure and

Figure 6 is a flow diagram for an example method according to the present disclosure.

DETAILED DESCRIPTION

[0005] In the following description the terms "a" and "an" are used to denote the presence of one or more of a particular element. The phrase "a material selected from the group comprising" following by a list of materials means the material comprises one or more materials selected from the list.

[0006] One example of the present disclosure discusses a computer device casing including a substrate, an electrically conductive coating on the substrate and either applying an electrophoretic deposition (ED) layer including a polymer on the electrically conductive coating or forming an anodized layer on the electrically conductive coating. The ED or anodized layer may impart certain desired properties, such as hardness or toughness, or a desired appearance or texture to the substrate. [0007] Examples will now be described in more detail with reference to the accompanying drawings.

[0008] Figure 1 shows a cross-sectional view of an example computer device casing 1 . The computer device may be any device such as a smart phone, tablet computer, laptop computer or desktop computer etc. The casing is a part of the exterior of the device and may for example shield internal components such as memory, processor, display circuitry etc. from the environment. In some examples, the casing may also provide support for a display, keyboard or other part of the device.

[0009] The computer device casing has a structure which includes a substrate 10, an electrically conductive layer 20 on the substrate and an ED layer 30 on the electrically conductive coating.

[0010] The substrate 10 has a first side 10A and a second side 10B opposite the first side. The sides 10A and 10B may for example be opposite faces of the substrate. The substrate 10 may include any appropriate material. For instance the substrate may comprise metal, carbon fibers, ceramics, composite material and/or plastics. The substrate may include a single layer, or may include a plurality of layers of the same or different materials. Depending upon the material or materials used, the substrate may be electrically conductive or electrically non-conductive.

[0011] The electrically conductive coating 20 may include any suitable electrically conductive material. For example the electrically conductive coating may include a metal, semiconductor material, conductive polymer, graphene, carbon fiber, synthetic graphite or carbon nanotubes etc. In one example the electrically conductive coating may include a light metal such as Aluminum, Magnesium, Lithium, Niobium, Titanium, Zinc or one of their alloys.

[0012] The ED layer 30 comprises a polymer. The polymer may be an anionic or cationic polymer. The ED layer may give a particular texture or desired appearance to the casing and/or may act as a protective layer. In some examples the ED layer may also include other particles in a polymer matrix. For instance the ED may include any or all of carbon black, titanium dioxide, clay, mica, talc, barium sulfate, calcium carbonate, synthetic pigment, metallic powder, aluminum oxide, graphene, graphite, organic or inorganic powders, silicon dioxide, dye, etc. Such additives may give particular desired appearances or properties. For example metal particles in the ED layer may give a metallic appearance to the casing.

[0013] In some examples the substrate 10 is electrically non-conductive. The substrate 10 is considered to be electrically non-conductive if it is formed of a single layer of electrically non-conductive material, or if it is formed of a plurality of layers and an outermost layer of the substrate such as side 10A and/or 10B is not electrically conductive. Where the substrate is electrically non-conductive, the application of an electrically conductive coating 20 provides an electrically conductive surface on at least one side which enables an ED to be applied. Without the electrically conductive coating 20 it may be difficult to apply an ED to an electrically non-conductive substrate.

[0014] In other examples the substrate 10 may be electrically conductive. The substrate 10 is considered to be electrically conductive if it is formed of a single layer of electrically conductive material, or if it is formed of a plurality of layers and the outermost layers of the substrate including sides 10A and 10B are electrically conductive. Where the substrate 10 is electrically conductive, it would be possible to apply an ED directly to the substrate 10. However, having the intermediate conductive layer may provide a particular desired appearance or other desired properties.

[0015] For example, the combination of the ED layer 30 and the conductive coating 20 beneath may provide a deep three dimensional layer texture and/or a superior appearance compared to an ED layer alone. Further, an ED layer in combination with the electrically conductive coating may be better able to pass certain environmental tests or regulations compared to an ED layer by itself with no intermediate electrically conductive coating.

[0016] Figure 2 shows an example similar to Figure 1 , but in which the ED layer is present on both sides of the substrate 10. This may for example occur if the substrate 10 is electrically conductive, as in that case an ED may also form on side 10B of the substrate even if there is no electrically conductive coating on that side. Thus in Figure 2 there is an ED layer 30 on one side of the substrate and the ED layer 30A on the other side of the substrate.

[0017] It is to be understood that while illustrated as separate layers 30A, 30B in Figure 2, these may in fact be the same ED layer and may be joined together at the edges. The ED is generally formed by immersing the substrate in a solution and applying an electric potential, so it is possible for the ED to form on all exposed electrically conductive surfaces.

[0018] Figure 3 shows another example which is similar to Figure 1 , except that the substrate has an electrically conductive coating 20 on both sides thereof 10A and 10B. This may be done for example if the substrate is not electrically conductive. In that case, if it is desired to have an ED on both sides then an electrically conductive coating may be applied to both sides of the substrate. In other cases the substrate may be electrically conductive, but the conductive coating may still be applied to both surfaces in order to meet environmental regulations or provide a particular desired appearance or texture on both sides of the casing for instance. In other examples, as shown in Figures 1 and 2 it may only be desired to add a conductive coating to one side of the substrate.

[0019] Figure 4 shows another example of a computer device casing, which is similar to Figure 1 , but instead of an ED layer 30 there is an anodized layer 40 on top of the conductive coating 20. As the conductive coating is to be anodized, the conductive coating 20 in this example is formed of a metal or metal alloy or includes metal particles. The anodized layer 40 comprises a metal oxide of the metal found in the electrically conductive coating 20. The anodized layer 40 may have a thickness greater than the thickness that an oxide layer formed naturally due to exposure to the environment would have.

[0020] The electrically conductive coating 20 may help to provide a metallic appearance to the casing, while the anodized layer 40 is a protective oxide layer and may provide improved toughness and wear resistance. For instance, if the electrically conductive coating is a light or soft metal then the anodized layer may help to reduce or prevent unseemly scratches or other damage to the surface that might otherwise easily occur. Further, if a lighter material such as plastic is used for the substrate, then the casing may be lighter compared to a casing made entirely of metal.

[0021] Figure 5 shows another example similar to Figure 4, except that there is an electrically conductive coating on both sides of the substrate. Thus an electrically conductive coating 20 is on the first side of the substrate and an electrically conductive coating 20A is on a second side of the substrate. In some examples the electrically conductive coating may be applied as a single coating to all surfaces of the substrate.

[0022] Figure 6 shows a flow diagram of an example method of forming an electronic device casing in accordance with the present disclosure.

[0023] At block 100 an electrically conductive coating is applied to a substrate. The electrically conductive coating may be applied to one or both sides of the substrate and may include any of the electrically conductive materials discussed above.

[0024] The electrically conductive coating may be applied to the substrate by any appropriate method, for instance physical vapor deposition, dipping, film transfer, screen printing or spray painting.

[0025] At block 1 10 an ED layer is applied to the electrically conductive coating or the electrically conductive coating is anodized.

[0026] The ED may for example be applied by partly or wholly immersing the substrate in a solution in which charged polymer particles are suspended. In one example the solution and charged polymer particles may be a colloid for instance, but this is not necessarily the case. The polymer particles may for example be 10 nm to 2 μπΊ in diameter. A potential difference is applied so that the electrically conductive coating has an opposite charge to that of the charged particles in the solution. The charged particles are then deposited onto electrically conductive coating. The polymer may for example be a polyacrylic polymer, epoxy polymer, elastomer or any other suitable polymers. In some examples metal, inorganic or other organic particles such as carbon black, titanium dioxide, clay, mica, talc, barium sulfate, calcium carbonate, synthetic pigment, metallic powder, aluminum oxide, graphene, graphite, organic or inorganic powders, silicon dioxide and dye may be present in the polymer matrix.

[0027] Anodizing may, for example, be carried out by partly or wholly immersing the coated substrate in an alkaline or acidic electrolyte and applying a potential difference. The electrically conductive coating may be cleaned or polished before subjecting it to the anodizing treatment. The anodizing treatment results in a protective layer which may have improved toughness and wear resistance.

Claims

WHAT IS CLAIMED IS:

1 . A computer device casing comprising:

a substrate;

an electrically conductive coating on the substrate;

an Electrophoretic Deposition (ED) layer on the conductive coating; the ED layer comprising a polymer.

2. The computer device of claim 1 wherein the substrate comprises a material selected from the group comprising metals, ceramics, composite materials and plastics.

3. The computing device of claim 1 wherein the substrate is electrically non- conductive.

4. The computer device of claim 1 wherein the electrically conductive coating includes a material selected from the group comprising: metals, conductive polymers, carbon fibers, graphene, synthetic graphite and carbon nanotubes.

5. The computer device of claim 1 wherein the substrate has a first side, a second side which is opposite the first side and an electrically conductive coating on both the first side and second side of the substrate.

6. The computer device of claim 1 wherein the ED layer comprises a polymer and an additive to the polymer, the additive selected from the group comprising: carbon black, titanium dioxide, clay, mica, talc, barium sulfate, calcium carbonate, synthetic pigment, metallic powder, aluminum oxide, graphene, graphite, organic or inorganic powders, silicon dioxide and dye.

7. A computer device casing comprising:

a substrate; an electrically conductive coating on the substrate; and an anodized layer on the electrically conductive coating.

8. The computer device casing of claim 7 wherein the substrate comprises a material selected from the group comprising metals, plastics, ceramics and composite materials.

9. The computer device casing of claim 7 wherein the substrate is electrically non-conductive.

10. The computer device casing of claim 7 wherein the electrically conductive coating comprises a metal.

1 1 . A method of treating a computer device casing comprising:- applying an electrically conductive coating to a substrate; and

applying an electrophoretic deposition (ED) including a charged polymer to the electrically conductive coating, or anodizing the electrically conductive coating.

12. The method of claim 1 1 wherein the substrate is electrically non-conductive.

13. The method of claim 1 1 wherein applying the electrically conductive coating comprises physical vapor deposition, dipping, film transfer, spray painting or screen printing the electrically conductive coating onto the substrate material.

14. The method of claim 1 1 further comprising applying an electrically conductive coating to two opposite sides of the substrate.

15. The method of claim 14 further comprising anodizing the electrically conductive coating on the two opposite sides of the substrate or applying an ED layer to the electrically conductive coating on the two opposite sides of the substrate.