WO2021050057A1

WO2021050057A1 - Casings for electronic devices

Info

Publication number: WO2021050057A1
Application number: PCT/US2019/050570
Authority: WO
Inventors: Kuan-Ting Wu; Chi Hao Chang; Hsing-Hung Hsieh
Original assignee: Hewlett-Packard Development Company, L.P.
Priority date: 2019-09-11
Filing date: 2019-09-11
Publication date: 2021-03-18

Abstract

Examples of a method for forming a casing for an electronic device are described. In an example, a method includes a passivating at least one chamfered portion of a metal casing with a transparent layer, sealing the transparent layer and depositing a finishing layer on a chamfered portion of the casing.

Description

CASINGS FOR ELECTRONIC DEVICES

BACKGROUND

[0001] Electronic devices, including peripherals, such as keyboards, laptops, tablets, and the like, are increasingly being designed for enhancing aesthetic appeal in addition to functionality. Such devices are housed in metal casings that are designed for both the aesthetic appeal and the ability to withstand chemical and mechanical stress. In some examples, the outer surface of the casing or device cover comprising the casing may be treated to provide patterned or textured finish to the electronic device.

BRIEF DESCRIPTION OF DRAWINGS

[0002] The following detailed description references the drawings, wherein: [0003] Fig. 1 illustrates a method for forming a metal casing, according to an example of the present disclosure.

[0004] Fig. 2 illustrates a method for forming a metal casing comprising insert molding a plastic on at least one surface of a metal casing, according to an example of the present disclosure.

[0005] Fig. 3 illustrates a method for forming a metal casing comprising electrophoretically depositing a finishing layer on a chamfered portion of the casing, according to an example of the present disclosure:

[0006] Fig. 4 illustrates an electronic device with a sectional view of a device cover comprising a metal casing, according to another example of the present disclosure.

DETAILED DESCRIPTION

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[0007] For convenience, before further description of the present disclosure, certain terms employed in the specification, and examples are described here. These definitions should be read in the light of the remainder of the present disclosure. The terms used herein have the meanings recognized and known to those of skilled in the art, however, for convenience and completeness, particular terms and their meanings are set forth below. [0008] The articles "a", "an", and "the” are used to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article.

[0009] The term "about* when referring to a numerical value is intended to encompass the values resulting from variations that can occur during the normal course of performing a method. Such variations are usually within plus or minus 5 to 10 percent of the stated numerical value.

[0010] The term "alloy” refers to the class of material that may be referred to as a mixture or solid solution of metals. The magnesium alloy in the present disclosure is selected from AZ91D, AZ31B, AZ60, AZ61, AZ63, AZ80, AZ81, AZ92, AM50, AM60, AM100, LZ91, LZ141, ALZ691, ALZ991, or combinations thereof.

[0011] The term “plastic-inserted casing", used herein refers to a metal casing comprising at least a section of a surface molded with a plastic by insertion molding. The plastic in the present disclosure is selected from polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), polyamide (nylon), polyacrylic, poiyphthalamide (PPA), acrylonitrile butadiene styrene (ABS), polyetherethe rketone (PEEK), polycarbonate (PC), or combinations thereof. [0012] The term “insertion molding”, and variations, such as "molding", used herein refers to the technique for manufacturing parts by inserting solid plastic part(s) into a mold during the process of molding. Insert molding may be carried out by insert injection molding at a temperature of from about 150 °C to about 400 °C.

[0013] The term "casing", used herein refers to a frame of light metal that is usable to obtain the device cover of the present disclosure. As described hereinbelow, the metal casing may be subjected to various treatments to obtain coatings including transparent layer, sealant layer, finishing layer, among others to obtain the aesthetical!y enhanced device cover. The metal casing may be obtainable by techniques such as thixo-molding or forging. Thixo-molding may be carried out at a temperature of from about 350 °C to about 700 °C Forging may be carried out at a temperature of from about 200 °C to about 500 °C. The light metal may be selected from magnesium, aluminum, lithium, titanium, zinc, stainless steel, or alloys thereof. A section of the casing may comprise insert- molded plastic.

[0014] The term “chemico-mechanically stable”, used herein refers to substrates having high tensile strength and/or high resistance to breakage and/or high corrosion resistance. Chemical stability towards corrosion may be rendered by passivation treatment.

[0015] The term “transparent finish”, used herein refers to a glossy transparent finish present on casing and/or device covers at the chamfered portions. Chamfering of at least a portion of the metal casing reveals shiny/iustrous metallic surface. The luster may be preserved by application of a transparent layer at chamfered portions, followed by a sealant layer.

[0016] The term “multi-colored finish", used herein refers to casing and/or device covers having different colors at different chamfered portions. In an example, the main body may have a first color, whereas, one of the chamfered portion (such as fingerprint scanner region) may have a second color. The multicolored finish is rendered to the casing by application of electrophoretic deposition in the presence of at least one dye at a chamfered portion.

[0017] Electronic device covers or casings are made of metals and are expected to have a combination of strength and visual appeal. While the low density of light metals coupled with ready compatibility with processes, such as spray coating, make them good choices for casings, light metals are not widely employed as they are prone to corrosion.

[0018] Moreover, metal casings, such as those comprising magnesium alloys, generally have a dull finish owing to passivation/oxidation. Therefore, an expensive lustrous over-coat is used on the metal casings for providing an appealing glossy finish to the final electronic device covers. However, machining processes such as chamfering lead to removal of the over-coat in the machined area, thus revealing a pristine layer that is prone to corrosion,

[0019] The present subject matter describes examples of methods for forming casings for electronic devices. In various examples, the methods comprise passivating at least one chamfered portion of a metal casing with a transparent layer, followed by sealing the transparent layer and subsequently depositing a finishing layer on a chamfered portion of the casing. In an example, the application of said layers post-chamfering, may result in an enhancement of corrosion resistance of said chamfered portions. In an example, a metal casing comprising said layers at the chamfered portion of a magnesium alloy casing can last up to a maximum of about 96 hours under salt fog test, whereas, the untreated chamfered portion of the same magnesium alloy can last a maximum of about 12 hours under salt fog test.

[0020] Further, the presence of a transparent layer on at least one chamfered portion may lead to high gloss finish at the edges. Chamfering may be carried out by a CNC diamond cutting machine or a laser engraving machine. In an example, the chamfering may be carried out with a laser engraving machine having a Nd:YAG laser under a laser power of from about 20 to about 200 W and an engraving speed of from about 300 to about 1200 mm/minute. In another example, the laser etching may be carried out under a laser power of from about 50 to about 150 W and an engraving speed of from about 350 to about 1100 mm/minute. In another example, the laser etching may be carried out at a laser power of about 100 W and an engraving speed of about 500 mm/minute. In another example, the chamfering may be carried out with a CNC diamond cutting machine at speed of from about 5000 to about 90000 rpm for a period of from about 3 to about 8 minutes. In another example, the chamfering may be carried out with a CNC diamond cutting machine at speed of from about 6000 to about 80000 rpm. Chamfering results in an etching that reveals the underlying shiny metallic casing surface.

[0021] Chamfering may be carried out on a portion of the casing. The chamfering may be carried out at portions such as clickpad, fingerprint scanner, edge, or sidewall. In an example, the chamfering is carried out at the edge. In another example, the chamfering may be carried out at the fingerprint scanner. [0022] The aesthetic quality of thus obtained casing and/or device covers may be quantified by measuring a gloss value. In an example, the gloss value of the chamfered casing may be of from about 85 to about 100 units as measured by American Society for Testing and Materials (ASTM) D523 at a viewing angle of about 60 °. This is found to be a clear enhancement from the unchamfered casing that result in a gloss value of from about 50 to about 75 units as measured by American Society for Testing and Materials (ASTM) D523 at a viewing angle of about 60°. In another example, the gloss value of the chamfered casing may be of from about 92 to about 100 units as measured by ASTM D523 at a viewing angle of about 60°.

[0023] Further, passivation of at least one chamfered portion to obtain a transparent layer helps preserve the glossy finish. In an example, the gloss value of the transparent layer formed on at least one chamfered portion of the casing may be of from about 90 to about 98 units as measured by ASTM D523 at a viewing angle of about 60°. In an example, the transparent layer may have a thickness of from about 0.03 mm to about 3.0 mm.

[0024] Further, sealing the transparent layer may provide a durability to the glossy finish. In an example, the sealant layer may have a thickness of from about 0.5 mm to about 3.0 mm. Sealant layer fills the surface pores and provide homogeneous surface profile, which may be particularly beneficial for achieving uniform electrophoretic deposition finishing layer.

[0025] Further, the deposition of finishing layer by an electrophoretic deposition in the presence of at least one dye at the chamfered portions may provide a multi-colored finish to the casing. In an example, the device cover is a keyboard casing having a first color at the finger print scanner area, a second color at the touch pad area, and a third color on remaining areas.

[0026] Overall, the methodology of passivating a metal casing with a transparent layer on at least one chamfered portion, sealing the transparent layer and depositing a finishing layer on a chamfered portion, according to the present subject matter, is simple, less time and resource consuming, and cost advantageous. Further, the device covers thus obtained are aesthetically appealing, while also being chemico-mechanically stable.

[0027] The following detailed description refers to the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the following description to refer to the same or similar parts. While several examples are described in the description, modifications, adaptations, and other implementations are possible. Accordingly, the following detailed description does not limit the disclosed examples. Instead, the proper scope of the disclosed examples may be defined by the appended claims.

[0028] Further, details of the method for forming a casing for an electronic device cover 100, is described with reference to Fig, 1. The transparent layer may be formed by passivating at least one chamfered portion of a metal casing 102. The formation of the transparent layer 102 may be carried out at a temperature of from about 15 °C to about 40 °C by dip coating method. In an example, the formation of the transparent layer 102 may be carried out at a temperature of from about 20 °C to about 35 °C. In another example, the formation of the transparent layer 102 may be carried out at a temperature of from about 22 °C to about 33 °C. In another example, the formation of the transparent layer 102 may be carried out at a temperature of from about 25 °C to about 30 °C.

[0029] The formation of the transparent layer 102 may be carried out on at least one chamfered portion of the metal casing. Chamfering may be carried out on a portion of the casing. The chamfering may be carried out at portions such as clickpad, fingerprint scanner, edge, or sidewall. In an example, the transparent layer may be formed at all the chamfered portions of the metal casing. In another example, the transparent layer may be formed at the clickpad.

[0030] In an example, the formation of the transparent layer 102 is carried out in the presence of at least one chelating agent selected from ethytenediaminetetraacetic acid, ethylenediamine, nitriloacetic acid, diethylenetriaminepenta(methylenephosphonic acid), nitrilotris(methy!enephosphonic acid), 1-hydroxyethane-1,1-diphosphonic acid, phosphoric acid, or salts thereof. In an example, the chelating agent is a salt of at least one metal selected from sodium, potassium, chromium, tin, indium, zinc, or combinations thereof. In another example, the chelating agent is ethytenediaminetetraacetic acid. In an example, the chelating agent may be employed at a concentration of from about 2% to about 10%. In an example, the chelating agent may be employed at a concentration of from about 4% to about 8%. In an example, the chelating agent may be employed at a concentration of about 6%. [0031] The transparent layer thus formed, may have a thickness of from about 0.03 mm to about 3.0 mm. In an example, the transparent layer may have a thickness of from about 0.05 mm to about 2.8 mm. In another example, the transparent layer may have a thickness of from about 0.1 mm to about 2.0 mm, In another example, the transparent layer may have a thickness of from about 0.5 mm to about 1.5 mm.

[0032] The metal casing may be pre-processed, for example, cleaned, dried, washed, polished, degreased, and activated, prior to passivation 102 to form transparent layer. The cleaning and washing may be performed using a buffer solution, which may help in removing foreign particles, if any, present on the surface of the metal casing. Further, the metal casing may be chemically polished using abrasives to remove irregularities that may be present on the surface of the metal casing. The metal casing may also be degreased through ultrasonic degreasing methods to remove impurities, such as fat, grease, or oil from the surface of the metal casing. Further, the metal casing may also be activated through acid treatment for removing the natural oxide layer, if any, present on the surface of the metal casing.

[0033] As shown Fig. 1 , the transparent layer can be sealed with a sealant layer 104. Forming the sealant layer 104 may be carried out at a temperature of from about 25 °C to about 100 °C by dip coating method. In an example, forming the sealant layer may be carried out at a temperature of from about 28 °C to about 98 °C. In another example, forming the sealant layer 104 may be carried out at a temperature of from about 35 °C to about 85 °C. In another example, forming the sealant layer 104 may be carried out at a temperature of about 30 °C.

[0034] In an example, the sealing of the transparent layer 104 is carried out in the presence of at least one chemical selected from aluminum fluoride, nickel fluoride, cerium fluoride, cerium acetate, aluminum acetate, nickel acetate, or combinations thereof. In an example, the chemical may be aluminum fluoride. In another example, the chemical may be nickel fluoride. In an example, sealing the transparent layer 104 may be carried out in the additional presence of an aqueous solution of a surfactant having a concentration of from about 0.1% to about 2.0 % by weight. In an example, the surfactant may be selected from sodium caseinate, sodium polyacrylate, sodium polyoxyethylene alkyl ether carboxylate, and sodium dodecyl sulfate. In another example, the surfactant may be sodium caseinate. [0035] The sealant layer thus formed, may have a thickness of from about 0.5 mm to about 3.0 mm. In an example, the transparent layer may have a thickness of from about 1.2 mm to about 2.5 mm. Sealant layer thus formed fills the surface pores and provide homogeneous surface profile, which may be particularly beneficial for achieving uniform electrophoretic deposition 106, thereby helping obtain an aesthetically improved finishing layer.

[0036] The deposition process 106, may be carried out by electrophoretic deposition. In an example, an electrophoretic deposition may be carried out subsequent to formation of the passivation layer to introduce colors and to provide multi-colored finish to the casing. In an example, a chamfered portion may have at least one different color as compared to the casing. In an example, the casing is a keyboard having a first color, the sidewall may have a second color and the fingerprint scanner may have a third color.

[0037] In an example, the deposition process 106 may be carried out by electrophoretic deposition in the presence of at least one dye to obtain a finishing layer. In an example, the dye may be selected from alexa fluor 594, texas red, pacific blue, pacific orange, quinoline yellow WS, red 168 MF, yellow 191 , titanium dioxide, mica, or combinations thereof.

[0038] The thickness of the finishing layer achieved may be directly related to the potential applied and time for electrophoretic deposition. In an example, the electrophoretic deposition may be carried out by applying a potential of from about 30 V to about 150 V for a period of from about 30 seconds to about 120 seconds. In another example, the electrophoretic deposition may be carried out by applying a potential of from about 40 V to about 140 V for a period of from about 40 seconds to about 110 seconds. In another example, the electrophoretic deposition may be carried out by applying a potential of about 80 V for a period of about 75 seconds. Further, the finishing layer thus deposited may be cured at an elevated temperature. In an example, the curing may be carried out at a temperature of from about 120 °C to about 180 °C for a period of from about 30 minutes to about 90 minutes. In another example, the curing may be carried out at a temperature of from about 125 °C to about 175 °C for a period of from about 35 minutes to about 85 minutes. In another example, the curing may be carried out at a temperature of from about 130 °C to about 170 °C for a period of from about 40 minutes to about 80 minutes. In another example, the curing may be carried out at a temperature of about 120 °C for about 60 minutes. The finishing layer thus formed, may have a thickness of from about 6.0 mm to about 25.0 mm. In an example, the finishing layer has a thickness of from about 12.0 mm to about 20.0 mm.

[0039] Depositing the finishing layer by electrophoretic deposition may be carried out in the presence of copolymers selected from polyacrylate copolymer, polyacrylic, epoxy, polyacrylamide-acrylic, and combinations thereof. In an example, the finishing layer may comprise copolymers of polyacrylate. In another example, the finishing layer may comprise copolymers of polyacrylamide-acrylic. [0040] The casing may be prepared, for example, cleaned, dried, degreased, washed and polished, prior to carrying out the deposition step 106 to obtain the finishing layer. In an example, the cleaning may be carried out in the presence of at least one aqueous alkaline compound such as sodium hydroxide. In an example, the polishing may be carried out in the presence of at least one acid selected from hydrochloric acid, nitric acid, phosphoric acid, or combinations thereof.

[0041] The device cover thus formed after the transparent passivation 102, sealing 104 and deposition, provides corrosion resistance to the chamfered portion apart from enhancing aesthetic appeal. In an example, a metal casing comprising a treated chamfered portion of a magnesium alloy casing can last up to a maximum of about 96 hours under salt fog test, whereas, the untreated chamfered portion of the same magnesium alloy can last a maximum of about 12 hours under salt fog test.

[0042] As described above, the passivation layer may be formed on at least one chamfered portion of a metal casing. The chamfering may be performed at a plastic-insert molded portion of the metal casing.

[0043] Fig. 2 illustrates a method for forming a plastic-inserted casing for an electronic device, according to an example of the present disclosure. In an example, the metal casing comprises a light metal selected from magnesium, aluminum, lithium, titanium, zinc, stainless steel, or alloys thereof. In another example, the metal casing comprises magnesium alloy selected from AZ91D, AZ31B, AZ60, AZ61 , AZ63, AZ80, AZ81, AZ92, AM50, AM60, AM100, LZ91, LZ141 , ALZ691 , ALZ991 , or combinations thereof. In another example, the metal casing comprises AZ31B. In another example, the metal casing comprises AZ60. [0044] The thickness of the metal casing may depend on the process employed to obtain the same. The metal casing may be obtained by thixo- molding, CNC (computerized numerical control) or forging. In an example, the metal casing may be obtained by thixo-molding at a temperature of from about 350 °C to about 700 °C. in another example, the metal casing may be obtained by forging at a temperature of from about 200 °C to about 500 °C. In an example, the metal casing may have a thickness of from about 0.3 mm to about 2.0 mm. In another example, the metal casing may have a thickness of about 0.6 mm to about 1.2 mm. In another example, the metal casing may have a thickness of about 0.7 mm.

[0045] Metal casing, in general, are impervious to radiofrequency (RF) signals. In an example, insertion molding of plastic may allow the metal casing to have regions that allow the RF signals to pass, thereby facilitating communication, such as 5G communication. In an example, the metal casing may be insert molded with a plastic selected from polybutyiene terephthatate (PBT), polyphenylene sulfide (PPS), polyamide (nylon), polyacrylic, polyphthalamide (PPA), acrylonitrile butadiene styrene (ABS), polyetheretherketone (PEEK), polycarbonate (PC), or combinations thereof. In an example, the plastic may be a combination of ABS and PC with glass fiber having a weight of from about 15 % to about 50 %. In another example, the plastic may be PBT. In another example, the plastic may be PPS. Metal fillers may interfere with radio signal transportation efficiency. In an example, the plastic is not reinforced with any metal filler. In an example, the insert molding 202 may be carried out at a temperature of from about 150 °C to about 400 °C. In another example, the insert molding 202 may be carried out at a temperature of from about 170 °C to about 380 °C, In another example, the insert molding 202 may be carried out at a temperature of from about 150 °C to about 350 °C. In an example, the plastic insert may have a thickness of from about 0.3 mm to about 2.0 mm. In another example, the plastic insert may have a thickness of about 1.2 mm. Subsequently, the plastic-inserted metal casing may be chamfered 204 at selected portions such as clickpad, fingerprint scanner, edge, or sidewall. In an example, the metal casing may be chamfered at the clickpad portion. In another example, the metal casing may be chamfered at the edge portion, Furthermore, the chamfered portion may be subjected to transparent passivation process 102, sealing process 104 and deposition process 106, as described hereinabove.

[0046] Fig. 3 illustrates a method for forming a plastic-inserted casing for an electronic device, according to an example of the present disclosure. As shown in Fig. 3, at least one surface of the metal casing may be deposited with a treatment layer prior to chamfering 302. In an example, the deposition of the treatment layer 302 may be carried out by oxidation, dip coating, spray coating, electrophoretic deposition, or combinations thereof. In another example, the deposition of the treatment layer 302 may be carried out by a combination of oxidation and spray coating. In another example, the deposition of the treatment layer 302 may be carried out by a combination of dip coating and electrophoretic deposition. Subsequently, the treated metal casing may be subjected to chamfering 204, transparent passivation 102, sealing process 104 and deposition process 106, as described hereinabove.

[0047] In an example, the deposition of the treatment layer 302 may be carried out by micro arc oxidation at a voltage of from about 150 V to about 550 V at a temperature of from about 10 °C to about 45T for a period of from about 2 minutes to about 25 minutes, In another example, the deposition of the treatment layer 302 may be carried out by micro arc oxidation at a voltage of from about 180 V to about 520 V at a temperature of from about 12 °C to about 42°C for a period of from about 5 minutes to about 22 minutes. In another example, the deposition of the treatment layer 302 may be carried out by micro arc oxidation at a voltage of from about 250 V to about 450 V at a temperature of about 35 °C for a period of about 15 minutes. The thickness of thus deposited layer, may be dependent on the voltage and time period of deposition. In an example, the deposition of the treatment layer 302 carried out by micro arc oxidation may form a treatment layer having a thickness of from about 3.0 mm to about 15.0 mm. In another example, the deposition of the treatment layer 302 carried out by micro arc oxidation may form a treatment layer having a thickness of from about 3.0 mm to about 7.0 mm.

[0048] In an example, the deposition of the treatment layer 302 may be carried out by micro arc oxidation in the presence of at least one additive selected from sodium silicate, metal phosphates, potassium fluoride, potassium hydroxide, sodium hydroxide, fluorozirconates, sodium hexametaphosphate, sodium fluoride, ferric ammonium oxalate, phosphoric acid salt, graphite powder, silicon dioxide powder, aluminum oxide powder, and combinations thereof. In an example, the additive may be employed at a dosage of from about 0.05% to about 15% in the presence of water at a pH of from about 9.0 to about 13.0. In another example, the additive may be employed at a dosage of from about 0.1% to about 12% in the presence of water at a pH of from about 9.0 to about 12.5.

[0049] In an example, the deposition of the treatment layer 302 may be carried out by a process of coating. The coating may be carried out by a process of dip coating. In an example, the deposition of treatment layer 302 may be carried out by dip coating for a period of from about 20 seconds to about 120 seconds. In an example, deposition of treatment layer 302 may be carried out by a process of dip coating for a period of from about 60 seconds to about 120 seconds. [0050] In an example, the deposition of the treatment layer 302 carried out by dip coating may be carried out in the presence of at least one salt of manganese, phosphates, molybdates, vanadates, chromates, stannate, and combinations thereof. In an example, the salt may be manganese. In another example, the salt may be phosphate. In an example, the salt may be dispersed in the form of an aqueous solution having a concentration of from about 3% to about 15% based on total weight. In an example, the salt may be dispersed in the form of an aqueous solution having a concentration of from about 3% to about 7% based on total weight. In an example, treatment layer thus formed may have a thickness of from about 1 mm to about 5 mm. In another example, the treatment layer may have a thickness of from about 1.5 mm to about 3.0 mm. [0051] In an example, the deposition of the treatment layer 302 may be carried out by spray coating. The obtained treatment layer may have a thickness of from about 15.0 mm to about 65.0 mm. In another example, depositing process 302 may result in a treatment layer having a thickness of from about 30.0 mm to about 60.0 mm. In another example, depositing process 302 may result in a treatment layer having a thickness of from about 35.0 mm to about 55.0 mm. In another example, depositing process 302 may result in a treatment layer having a thickness of about 44.0 mm. In an example, the treatment layer thus formed may comprise multiple layers, such as primer, base coat and top coat.

[0052] In an example, the primer may be deposited on the metal casing by spray coating polyurethanes followed by heat treatment at a temperature of from about 60 °C to about 80 °C for a period of from about 15 to about 40 minutes. In another example, the primer may be deposited by spray coating polyurethane followed by heat treatment at a temperature of from about 62 °C to about 78 °C for a period of from about 18 to about 38 minutes. In another example, the primer may be deposited by spray coating thermoplastics, such as polyurethanes followed by heat treatment at a temperature of about 60 °C for a period of about 40 minutes.

[0053] In an example, the base coat may comprise polyurethane containing pigments selected from carbon black, titanium dioxide, clay, mica, talc, barium sulfate, calcium carbonate, aluminum oxide, plastic bead, dyes, and combinations thereof. In an example, the spray coated base coat comprises polyurethane containing carbon black. In another example, the spray coated base coat comprises polyurethane containing titanium dioxide. In another example, the spray coated base coat comprises polyurethane containing clay.

[0054] In an example, the base coat deposited by spray coating may be followed by heat treatment at a temperature of from about 60 °C to about 80 °C for a period of from about 15 to about 40 minutes. In another example, the base coat deposited by spray coating may be followed by heat treatment at a temperature of from about 62 °C to about 78 °C for a period of from about 18 to about 38 minutes. In another example, the base coat deposited by spray coating may be followed by heat treatment at a temperature of about 70 °C for a period of about 25 minutes.

[0055] In an example, the top coat may be made of polyacrylic, polyurethane, urethane acrylates, acrylic acrylates, epoxy acrylates, or combinations thereof. In an example, the top coat may be made of polyacrylic. In another example, the top coat may be made of polyurethane. In another example, the top coat may be made of urethane acrylates.

[0056] In an example, the top coat deposited by spray coating may be followed by UV treatment having an intensity of from about 700 mJ/cm² to about 1200 mJ/cm² for a period of from about 10 seconds to about 30 seconds. In another example, the top coat deposited by spray coating may be followed by UV treatment having an intensity of from about 800 mJ/cm² to about 1100 mJ/cm² for a period of from about 15 seconds to about 25 seconds. In another example, the top coat deposited by spray coating may be followed by UV treatment of about 950 mJ/cm² for a period of about 20 seconds.

[0057] In another example, the top coat deposited by spray coating a polyurethane may be followed by heat treatment at a temperature of from about 60 °C to about 80 °C for a period of from about 15 to about 40 minutes. In another example, the top coat deposited by spray coating may be followed by heat treatment at a temperature of from about 62 °C to about 78 °C for a period of from about 18 to about 38 minutes. In another example, the top coat deposited by spray coating may be followed by heat treatment at a temperature of about 70 °C for a period of about 25 minutes.

[0058] The deposition of the treatment layer 302, may be carried out by electrophoretic deposition. In an example, an electrophoretic deposition may be carried out subsequent to formation of the passivation layer to introduce colors and to provide aesthetically improved finish prior to chamfering. The thickness of the finishing layer achieved may be directly related to the potential applied and time for electrophoretic deposition. In an example, the electrophoretic deposition may be carried out by applying a potential of from about 30 V to about 150 V for a period of from about 30 seconds to about 120 seconds. In another example, the electrophoretic deposition may be carried out by applying a potential of from about 60 V to about 130 V for a period of from about 60 seconds to about 100 seconds. In another example, the electrophoretic deposition may be carried out by applying a potential of about 110 V for a period of about 80 seconds.

[0059] In an example, the treatment layer deposited by electrophoretic deposition may comprise at least one chemical selected from polyacrylic polymer, polyacrylamide-acrylic copolymer and epoxy-containing polymer. In another example, the chemical is polyacrylic polymer. In an example, the electrophoretic deposition may be carried out in the presence of at least one dye selected from alexa fluor 594, texas red, pacific blue, pacific orange, quinoline yellow WS, pignment red 168 MF, pigment yellow 191 , or combinations thereof.

[0060] Further, details of the electronic device cover 400, is described with reference to Fig. 4. The method as described hereinabove, may be applied conveniently for forming device covers for a range of electronic devices such as keyboards, laptops, tablets, mobile phones, among others. As shown in the Fig. 4, in an example, the electronic device 402 is a laptop comprising a specific chamfered portion 404 and the unchamfered portions 406. In an example, the chamfered portion 404 may be the fingerprint scanner region. The electronic device primarily comprises the metal casing 408.

[0061] In an example, the metal casing 408 comprises a light metal selected from magnesium, aluminum, lithium, titanium, zinc, stainless steel, or alloys thereof. In another example, the metal casing comprises magnesium alloy selected from AZ91D, AZ31B, AZ60, AZ61, AZ63, AZ80, AZ81, AZ92, AM50, AM60, AM100, LZ91 , LZ141, ALZ691 , ALZ991, or combinations thereof. In another example, the metal casing comprises AZ31B. In another example, the metal casing comprises AZ60.

[0062] The thickness of the metal casing 408 may be reliant on the process employed to obtain the same. The metal casing may be obtained by thixo- molding, CNC or forging. In an example, the metal casing may be obtained by thixo-molding. In another example, the metal casing may be obtained by forging. In an example, the metal casing may have a thickness of from about 0.3 mm to about 2.0 mm. In another example, the metal casing may have a thickness of about 0.5 mm to about 1.2 mm. In another example, the metal casing may have a thickness of about 0.7 mm. In an example, the metal casing 408 may be insertion molded with plastic selected from polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), polyamide (nylon), polyacrylic, polyphthalamide (PPA), acrylonitrile butadiene styrene (ABS), polyetheretherketone (PEEK), polycarbonate (PC), or combinations thereof. In another example, the metal casing 408 may be insertion molded with PBT. In another example, the metal casing 408 may be insertion molded with PPS.

[0063] In an example, a treatment layer 410 may be deposited on at least one surface of the metal casing 408. The treatment layer 410 may be deposited by a process 302 selected from oxidation, coating, spray coating, electrophoretic deposition, or combinations thereof .

[0064] The treatment layer 410 may be deposited by micro arc oxidation. In an example, the treatment layer 410 deposited by micro arc oxidation may have a thickness of from about 3.0 mm to about 15.0 mm. In another example, the treatment layer 410 deposited by micro arc oxidation may have a thickness of from about 4.0 mm to about 12.0 mm.

[0065] In an example, the treatment layer 410 may be deposited by micro arc oxidation may comprise at least one additive selected from sodium silicate, metal phosphates, potassium fluoride, potassium hydroxide, sodium hydroxide, fluorozirconates, sodium hexametaphosphate, sodium fluoride, ferric ammonium oxalate, phosphoric acid salt, graphite powder, silicon dioxide powder, aluminum oxide powder, and combinations thereof. In an example, the additive may be employed at a dosage of from about 0.05% to about 15% in the presence of water at a pH of from about 9.0 to about 13.0. In another example, the additive may be employed at a dosage of from about 0.1% to about 12% in the presence of water at a pH of from about 9.0 to about 12.5.

[0066] In an example, the treatment layer 410 may be deposited by dip coating. In an example, the deposition of the treatment layer 410 deposited by dip coating may comprise at least one salt of manganese, phosphates, molybdates, vanadates, chromates, stannate, and combinations thereof. In an example, the salt may be manganese. In another example, the salt may be phosphate. In an example, the salt may be dispersed in the form of an aqueous solution having a concentration of from about 3% to about 15% based on total weight. In an example, the salt may be dispersed in the form of an aqueous solution having a concentration of from about 3% to about 7% based on total weight. In an example, treatment layer 410 thus formed may have a thickness of from about 1 mm to about 5 mm. In another example, the treatment layer may have a thickness of from about 1.5 mm to about 3.0 mm.

[0067] In an example, the treatment layer 410 may be deposited by spray coating. The thus obtained treatment layer 410 may have a thickness of from about 15.0 mm to about 65.0 mm. In another example, the treatment layer 410 may have a thickness of from about 30.0 mm to about 60.0 mm. In another example, the treatment layer 410 may have a thickness of from about 35.0 mm to about 55.0 mm. In another example, the treatment layer 410 may have a thickness of about 44.0 mm. In an example, the treatment layer 410 deposited by spray coating may comprise multiple layers, such as primer, base coat and top coat. [0068] In an example, the spray coated treatment layer 410 comprises sequentially deposited coats of primer having a thickness of from about 5.0 mm to about 20.0 mm, followed by base coat having a thickness of from about 10.0 mm to about 20.0 mm, followed by top coat having a thickness of from about 10.0 mm to about 25.0 mm.

[0069] The metal casing 408 may be cleaned, dried, degreased and washed prior to deposition of the treatment layer 410. The treatment layer 410 may comprise primer, either alone or in combination with one or more other layers. The primer may also be applied as single or multiple coats to achieve desired thickness and finish. In an example, the primer may have a thickness of from about 5.0 mm to about 20.0 mm. In another example, the primer may have a thickness of from about 8.0 mm to about 18.0 mm. In another example, the primer may have a thickness of about 12.0 mm.

[0070] The treatment layer 410 may comprise base coat, in combination with one or more other layers. The base coat may also be applied as single or multiple coats to achieve desired thickness and finish, in an example, the base coat may have a thickness of from about 10.0 mm to about 20.0 mm. In another example, the base coat may have a thickness of from about 12.0 mm to about 18.0 mm. In another example, the base coat may have a thickness of about 15.0 mm. In an example, the base coat may be a polyurethane containing pigments selected from carbon black, titanium dioxide, clay, mica, talc, barium sulfate, calcium carbonate, aluminum oxide, plastic bead, dyes, and combinations thereof. In an example, the spray coated base coat comprises polyurethane containing carbon black. In another example, the spray coated base coat comprises polyurethane containing titanium dioxide. In another example, the spray coated base coat comprises polyurethane containing clay.

[0071] The treatment layer 410 may comprise top coat, in combination with one or more other layers. The top coat may also be applied as single or multiple coats to achieve desired thickness and finish. In an example, the top coat may have a thickness of from about 10.0 mm to about 25.0 mm. In another example, the top coat may have a thickness of from about 12.0 mm to about 22.0 mm. In another example, the top coat may have a thickness of about 17.0 mm. In an example, the top coat may be made of polyacrylic, polyurethane, urethane acrylates, acrylic acrylates, epoxy acrylates, or combinations thereof. In an example, the top coat is made of polyacrylic. In another example, the top coat may be made of polyurethane. In another example, the top coat may be made of urethane acrylates.

[0072] The treatment layer 410, may be deposited by electrophoretic deposition. In an example, the electrophoretic deposition may result in deposition of a treatment layer 410 having a thickness of from about 15.0 mm to about 40.0 mm. In another example, the electrophoretically deposited treatment layer 410 may have a thickness of from about 17.0 mm to about 38.0 mm. In another example, the electrophoreticaliy deposited treatment layer 410 may have a thickness of from about 20.0 mm to about 35.0 mm. In another example, the electrophoretically deposited treatment layer 410 may have a thickness of about 20 mm.

[0073] The treatment layer 410 deposited by electrophoretic deposition may comprise electrophoretic deposition may comprise at least one chemical selected from polyacrylic polymer, polyacrylamide-acrylic copolymer and epoxy-containing polymer. In another example, the chemical is polyacrylic polymer. In an example, the electrophoretic deposition may be carried out in the presence of at least one dye selected from alexa fluor 594, texas red, pacific blue, pacific orange, quinoline yellow WS, pignment red 168 MF, pigment yellow 191, or combinations thereof.

[0074] Chamfering may be carried out on a portion of the casing. The chamfering may be carried out at portions such as clickpad, fingerprint scanner, edge, or sidewall. In an example, the transparent layer may be formed at all the chamfered portions of the metal casing. In another example, the transparent layer may be formed at the fingerprint scanner 404. At the chamfered portion 404, metal casing 408 may be passivated with a transparent layer 412.

[0075] In an example, the transparent layer 412 comprises at least one chelating agent selected from ethyienediaminetetraacetic acid, ethyienediamine, nitriloacetic acid, diethylenetriaminepenta(methylenephosphonic acid), nitrilotris(methylenephosphonic acid), 1-hydroxyethane-1,1-diphosphonic acid, phosphoric acid, or salts thereof. In an example, the chelating agent may be a salt of at least one metal selected from sodium, potassium, chromium, tin, indium, zinc, or combinations thereof. In another example, the chelating agent may be ethyienediaminetetraacetic acid. In an example, the chelating agent may be employed at a concentration of from about 2% to about 10%. In an example, the chelating agent may be employed at a concentration of from about 4% to about 8%. In an example, the chelating agent may be employed at a concentration of about 6%

[0076] The transparent layer 412, may have a thickness of from about 0.03 mm to about 3.0 mm. In an example, the transparent layer 412 may have a thickness of from about 0.05 mm to about 2.8 mm. In an example, the transparent layer may have a thickness of from about 0.05 mm to about 2.8 mm. In another example, the transparent layer may have a thickness of from about 0.1 mm to about 2.0 mm. In another example, the transparent layer may have a thickness of from about 0.5 mm to about 1.5 mm.

[0077] A sealant layer 414, may be deposited on the transparent layer 412. In an example, the sealant layer 414 comprises at least one chemical selected from aluminum fluoride, nickel fluoride, cerium fluoride, cerium acetate, aluminum acetate, nickel acetate, or combinations thereof. In an example, the chemical may be aluminum fluoride. In another example, the chemical may be nickel fluoride. The sealant layer 414, may have a thickness of from about 0.5 mm to about 3.0 mm. In an example, the sealant layer 414 has a thickness of from about 1.0 mm to about 2.5 mm.

[0078] The finishing layer 416, may be deposited by electrophoretic deposition. In an example, an electrophoretic deposition may be carried out subsequent to formation of the transparent layer 412 to introduce colors and to provide multi-colored finish to the casing. In an example, a chamfered portion may have at least one different color as compared to the casing. In an example, the casing is a keyboard having a first color, the sidewall has a second color and the fingerprint scanner has a third color.

[0079] In an example, the finishing layer 416 may be deposited by electrophoretic deposition in the presence of at least one dye to obtain a finishing layer. In an example, the dye may be selected from alexa fluor 594, texas red, pacific blue, pacific orange, quinoline yellow WS, red 168 MF, yellow 191 , titanium dioxide, mica, or combinations thereof. The finishing layer 416 thus formed, may have a thickness of from about 6.0 mm to about 25.0 mm. In an example, the finishing layer has a thickness of from about 10.0 mm to about 15.0 pm.

[0080] Depositing the finishing layer 416 by electrophoretic deposition may be carried out in the presence of copolymers selected from polyacrylate copolymer, polyacrylic, epoxy, polyacrylamide-acrylic, and combinations thereof. In an example, the finishing layer 416 may comprise copolymers of polyacrylate. In another example, the finishing layer 416 may comprise copolymers of polyacrylamide-acrylic. In an example, the treatment layer 410 in combination with finishing layer 416 provides a patterned finish to the device cover.

EXAMPLES

[0081 ] The description hereinafter describes prophetic examples, which are intended to illustrate examples of the present disclosure and not intended to be taken restrictively to imply any limitations on the scope of the present disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure belongs. It is to be understood that this disclosure is not limited to the particular methods and experimental conditions described, as such methods and conditions may vary depending on the process and inputs used as will be easily understood by a person skilled in the art.

[0082] A magnesium alloy (AZ91 D) casing having a thickness of 0.7 mm is obtained by thixo-molding carried out at a temperature of about 640 °C.

[0083] Subsequently, the metal casing is subjected to chamfering using a CNC diamond cutting machine. The chamfering is done by using a speed of about 22000 rpm and an engraving speed of about 900 mm/minute.

[0084] The chamfered portion (fingerprint scanner region) is passivated with a transparent layer comprising ethylenediaminetetracetic acid. The transparent layer is formed by dip coating at a temperature in the range of 15-40 °C.

[0085] The transparent layer is subsequently sealed with aluminum fluoride to obtain a sealant layer having a thickness of 2 mm. The sealant layer is deposited at a temperature of 30 °c in the additional presence aqueous solution of sodium polyacrylate having about 0.3 % by weight. The sealant layer is formed by dip coating method having a thickness of about 1.5 mm.

[0086] Subsequently, a finishing layer is electrophoretically deposited at chamfered portion. The chamfered portion may be the same as the one where the sealant layer was deposited or may be a different chamfered portion. The finishing layer is deposited in presence of polyacrylic polymer under a voltage of 80 V for 75 seconds followed by curing at 120 °C for 60 minutes to obtain a finishing layer having a thickness of about 15.5 mm.

Prophetic Example 2

[0087] A magnesium alloy (AZ91D) is insertion molded with a plastic (polybutylene terephthalate or PBT) to obtain the metal casing. Said magnesium alloy has a thickness of 0.7 mm, whereas the plastic insert has a thickness of 0.7 mm. The magnesium alloy is obtained by thixo-molding carried out at a temperature of about 640 °C.

[0088] Subsequently, the metal casing is subjected to chamfering using a CNC diamond cutting machine. The chamfering is done by using a speed of about 22000 rpm and an engraving speed of about 500 mm/minute. [0089] The chamfered portion (fingerprint scanner region) is passivated with a transparent layer comprising ethylenediaminetetracetic acid. The transparent layer is formed by dip coating method.

[0090] The transparent layer is subsequently sealed with aluminum fluoride to obtain a sealant layer having a thickness of 2 mm. The sealant layer is deposited at a temperature of 30 °C in the additional presence of an aqueous solution of a surfactant having a concentration of from about 0.1% to about 2.0 % by weight. The sealant layer is formed by dip coating method.

[0091] Subsequently, a finishing layer is electrophoretically deposited at chamfered portion. The chamfered portion may be the same as the one where the sealant layer was deposited or may be a different chamfered portion. The finishing layer is deposited in presence of polyacrylic polymer under a voltage of 80 V for 75 seconds followed by curing at 120 °C for 60 minutes to obtain a finishing layer having a thickness of about 13.0 mm.

Prophetic Example 3

[0092] A magnesium alioy (AZ91D) is insertion molded with a plastic (polybutylene terephthalate or PBT) to obtain the metal casing. The magnesium alloy has a thickness of 0.7 mm, whereas the plastic insert has a thickness of 0.7 mm. The magnesium alloy is obtained by thixo-molding carried out at a temperature of about 640 °C.

[0093] Subsequently, the metal casing is subjected to passivation by microarc oxidation at a voltage of 430 V to obtain a thickness of about 12 mm. Further, a finishing layer having a thickness of about 55 mm is deposited by spray coating. [0094] The spray coating is carried out in a step-wise manner. Herein, the polyurethane primer is first deposited by spray coating followed by heat treatment at 70 °C for a period of 25 minutes. Said primer has a thickness of about 12 mm. This is followed by the deposition of a base coat made of carbon-black containing polyurethane. The deposition is carried out by spray coating followed by heat treatment at 70 °C for a period of 25 minutes. The base coat has a thickness of 15 mm. Finally, a top coat made of urethane acrylate is applied by spray coating followed by UV treatment at 950 mJ/cm² for a period of 20 seconds. The top coat has a thickness of 17 mm. [0095] After deposition, the metal casing is subjected to chamfering using a CNC diamond cutting machine. The chamfering is done by using a speed of about 18000 rpm and an engraving speed of about 500 mm/minute.

[0096] The chamfered portion (fingerprint scanner region) is passivated with a transparent layer comprising ethylenediaminetetracetic acid. The transparent layer is formed by dip coating method.

[0097] The transparent layer is subsequently sealed with aluminum fluoride to obtain a sealant layer having a thickness of 2 mm. The sealant layer is deposited at a temperature of 30 °C, in the additional presence of an aqueous solution of a surfactant having a concentration of from about 0.1% to about 2.0 % by weight. The sealant layer is formed by dip coating method.

[0098] Subsequently, a finishing layer is electrophoretically deposited at chamfered portion. The chamfered portion may be the same as the one where the sealant layer was deposited or may be a different chamfered portion. The finishing layer is deposited in presence of polyacrylic polymer under a voltage of 110 V for 60 seconds followed by curing at 120 °C for 60 minutes to obtain a finishing layer having a thickness of about 17.0 mm.

Prophetic Example 4

[0099] A magnesium alloy (AZ91D) is insertion molded with a plastic (polybutylene terephthalate or PBT) to obtain the metal casing. Said magnesium alloy has a thickness of 0.7 mm, whereas the plastic insert has a thickness of 0.7 mm. The magnesium alloy is obtained by thixo-molding carried out at a temperature of about 640 *c.

[00100] Subsequently, the metal casing is subjected to passivation by microarc oxidation at a voltage of 350 V to obtain a thickness of about 10.0 mm. Further, a finishing layer having a thickness of about 20.0 mm is deposited by electrophoretic deposition.

[00101] The electrophoretic deposition is carried out at a potential of 120 V for 80 seconds.

[00102] After deposition, the metal casing is subjected to chamfering using a CNC diamond cutting machine. The chamfering is done by using speed of about 18000 rpm and an engraving speed of about 900 mm/minute. [00103] The chamfered portion (fingerprint scanner region) is passivated with a transparent layer comprising ethylenediaminetetracetic acid. The transparent layer is formed by dip coating method.

[00104] The transparent layer is subsequently sealed with aluminum fluoride to obtain a sealant layer having a thickness of 2 mm. The sealant layer is deposited at a temperature of 30 °c. in the additional presence of an aqueous solution of a surfactant having a concentration of from about 0.1% to about 2.0 %. The sealant layer is formed by dip coating method.

[00105] Subsequently, a finishing layer is electrophoretically deposited at chamfered portion. The chamfered portion may be the same as the one where the sealant layer was deposited or may be a different chamfered portion. The finishing layer is deposited in presence of polyacrylic polymer under a voltage of 80 V for 75 seconds followed by curing at 120 °c for 60 minutes by weight to obtain a finishing layer having a thickness of about 17.0 mm.

[00106] Although examples for the present disclosure have been described in a language specific to structural features and/or methods, it is to be understood that the appended claims are not limited to the specific features or methods described herein. Rather, the specific features and methods are disclosed and explained as examples of the present disclosure.

Claims

We Claim:

1. A method for forming a casing for an electronic device, the method comprising:

(a) passivating at least one chamfered portion of a metal casing to obtain a transparent layer;

(b) sealing the transparent layer to obtain a sealant layer; and

(c) depositing a finishing layer on a chamfered portion of the casing.

2. The method as claimed in claim 1, wherein passivating at least one chamfered portion of a metal casing is carried out in the presence of at least one chelating agent selected from ethylenediaminetetraacetic acid, ethylenediamine, nitriloacetic acid, diethylenetriaminepenta(methylenephosphonic acid), nitrilotris(methylenephosphonic acid), 1-hydroxyethane-1,1-diphosphonic acid, phosphoric acid, or salts thereof to obtain a transparent layer having a thickness of from about 0.03 mm to about 3.0 mm.

3. The method as claims in claim 1 , wherein sealing the transparent layer is carried out in the presence of at least one chemical selected from aluminum fluoride, nickel fluoride, cerium fluoride, cerium acetate, aluminum acetate, nickel acetate, or combinations thereof to obtain a sealant layer having a thickness of from about 0.5 mm to about 3.0 mm.

4. The method as claimed in claim 1 , wherein depositing the finishing layer is carried out by electrophoretic deposition in the presence of at least one dye to obtain a finishing layer having a thickness of from about 6.0 mm to about 25.0 mm.

5. The method as claimed in claim 1 , wherein depositing the finishing layer provides a multi-colored finish to the casing.

6. A method for forming a plastic-inserted casing for an electronic device, the method comprising:

(a) insert molding a plastic on at least one surface of a metal casing;

(b) chamfering at least a portion of the metal casing;

(c) passivating at least one chamfered portion of the casing to obtain a transparent layer;

(d) sealing the transparent layer to obtain a sealant layer; and

(e) depositing a finishing layer on a chamfered portion of the casing.

7. The method as claimed in claim 6, wherein the metal casing comprises a light metal selected from magnesium, aluminum, lithium, titanium, zinc, stainless steel, or alloys thereof and the plastic is selected from polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), polyamide (nylon), polyacrylic, polyphthalamide (PPA), acrylonitrile butadiene styrene (ABS), polyetheretherketone (PEEK), polycarbonate (PC), or combinations thereof.

8. The method as claimed in claim 6, insert molding a plastic is carried out at a temperature of from about 150 °C to about 400 °C,

9. An electronic device cover, the electronic device cover comprising:

(a) a metal casing;

(b) a transparent layer disposed on at least one chamfered portion of the casing;

(c) a sealant layer deposited on the transparent layer; and

(d) a finishing layer on a chamfered portion of the casing.

10. The electronic device cover as claimed in claim 9, the device cover comprising: the metal casing having a thickness of from about 0.3 mm to about 2.0 mm; the transparent layer having a thickness of from about 0.03 mm to about 3.0 mm; the sealant layer having a thickness of from about 0.5 mm to about 3.0 mm; and the finishing layer having a thickness of from about 6.0 mm to about 25.0 mm.

11. The electronic device cover as claimed in claim 9, the device cover comprising: a treatment layer deposited on the metal casing prior to chamfering by a process selected from oxidation, coating, spray coating, electrophoretic deposition, or combinations thereof.

12. The electronic device cover as claimed in claim 11, wherein the treatment layer is deposited by oxidation and has a thickness of from about 3.0 mm to about 15.0 mm.

13. The electronic device cover as claimed in 11 , wherein the treatment layer is deposited by coating in the presence of at least one salt of manganese, phosphates, molybdates, vanadates, chromates, stannate, manganese, or combinations thereof and having a thickness of from about 1.0 mm to about 5.0 mm.

14. The electronic device cover as claimed in claim 11, wherein the treatment layer deposited by spray coating comprises: a primer having a thickness of from about 5.0 mm to about 20.0 mm; a base coat having a thickness of from about 10.0 mm to about 20.0 mm; and a top coat having a thickness of from about 10.0 mm to about 25.0 mm.

15. The electronic device cover as claimed in claim 11 , wherein the treatment layer in combination with finishing layer provides a patterned finish to the device cover.