Metal housing and preparation method therefor, and electronic terminal product

Abstract

A metal housing and a preparation method therefor, and an electronic terminal product. The metal housing comprises a base plate, a frame and a retaining strip, wherein the base plate, the frame and the retaining strip are each at least partially covered with a pattern layer. The pattern layers comprise nanopores, wherein the nanopores are filled with a dye; the dye on the base plate, the dye on the frame and the dye on the retaining strip form continuous patterns; and any two of the pattern on the frame, the pattern on the retaining strip and the pattern on the base plate are substantially the same color.

Description

Metal shell, preparation method thereof, and electronic terminal product

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on March 29, 2024, with application number 202410385478.4 and application name “A metal shell, its preparation method and electronic terminal product”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of terminal shell processing, and more specifically, to a metal shell and a preparation method thereof and an electronic terminal product. Background Art

[0003] As electronic products gradually adopt metal as their casings, consumers have higher and higher requirements for the appearance and texture of metal casings. Therefore, in addition to meeting the requirements of wear resistance and corrosion resistance, metal casings also need to have a rich and diverse metal appearance or be able to present patterns of different levels.

[0004] If the front, side and back end faces of the metal shell need to be decorated at the same time, the metal substrate needs to be sprayed, masked and exposed, and the upper side needs to be decorated multiple times. This will result in a longer metal shell processing process, a lower yield rate of the metal shell, and increased costs. Summary of the Invention

[0005] An object of one embodiment of the present disclosure is to provide a metal housing, a preparation method thereof, and an electronic terminal product, so as to solve the technical problems of the surface processing technology of the metal housing in the related art.

[0006] In a first aspect, the present disclosure provides a metal housing, comprising:

[0007] A base plate, a frame and a baffle; the base plate, the frame and the baffle are at least partially covered with a pattern layer, the pattern layer comprising nanopores; the nanopores are filled with dyes; the dyes on the base plate, the frame and the baffle form a continuous pattern; the colors of any two of the patterns on the frame, the baffle and the base plate are substantially the same.

[0008] In a second aspect, the present disclosure further provides an electronic terminal product, comprising the above-mentioned connected metal shell.

[0009] In combination with the above technical solution, the base plate, frame and baffle of the metal shell provided by the present invention are at least partially covered with a pattern layer having nanopores, and the nanopores are filled with dyes, so that the dyes on the base plate, frame and baffles form a continuous pattern, thereby realizing continuous decorative patterns in multiple areas of the metal shell, and the colors of the baffles and frames of the same color are roughly the same, and the colors of any two of the baffles, frames and base plate remain consistent, and the continuous pattern presents a uniform color. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG1 is a schematic structural diagram of a metal shell provided in some embodiments of the present disclosure.

[0011] FIG2 is a schematic structural diagram of the metal housing shown in FIG1 from another direction.

[0012] FIG. 3 is a schematic diagram of a partial structure of a pattern on the metal shell shown in FIG. 1 .

[0013] FIG. 4 is a schematic diagram of a partial structure of a pattern on the metal shell shown in FIG. 1 .

[0014] FIG5 is a partial structural diagram of a pattern on a metal shell provided by the related art.

[0015] FIG6 is a schematic structural diagram of the cooperation between the metal shell and the contoured jig provided in some embodiments of the present disclosure.

[0016] FIG. 7 is a schematic structural diagram of the metal shell and the profiling fixture shown in FIG. 6 in another direction of cooperation.

[0017] FIG8 is a schematic structural diagram of a base and a frame provided in some embodiments of the present disclosure. DETAILED DESCRIPTION

[0018] The following describes the specific embodiments of the present disclosure in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure and are not intended to limit the present disclosure.

[0019] In the present disclosure, unless otherwise stated, the directional words used, such as "above", "below", etc., are generally defined in terms of the drawing direction of the corresponding drawings, and are only for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, and a specific orientation structure and operation, and therefore cannot be understood as a limitation on the present disclosure. "Inside" and "outside" refer to the inside and outside of the outline of the corresponding component. The use of terms such as "first" and "second" is intended to distinguish different components and does not have sequentiality and importance. Among them, the X direction shown in Figure 1 can be the first direction, the Y direction can be the second direction, and the Z direction can be the plug-in direction of the first connecting structure 2 and the second connecting structure 3. In addition, in the following description, when referring to the drawings, unless otherwise explained, the same figure marks in different drawings represent the same or similar elements.

[0020] It should also be noted that, in the description of this disclosure, unless otherwise expressly specified or limited, the terms "disposed," "connected," "connected," and "installed" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections; and they may refer to direct connections or indirect connections via an intermediary. Those skilled in the art will understand the specific meanings of these terms in this disclosure based on specific circumstances.

[0021] As electronic products gradually adopt metal as their casings, consumers have higher and higher requirements for the appearance and texture of metal casings. Therefore, in addition to meeting the requirements of wear resistance and corrosion resistance, metal casings also need to have a rich and diverse metal appearance or be able to present patterns of different levels.

[0022] If the front, side, and back ends of a metal shell are to be decorated simultaneously, the current process includes the following steps: ① spraying a photosensitive coating on the surface of the metal substrate; ② partially masking and exposing the front, side, and back ends of the shell; ③ using a developer to remove the photosensitive coating in the masked area to achieve partial masking; ④ decorating and coloring the unmasked area using anodizing; ⑤ stripping the partially masked coating; ⑥ performing a secondary anodizing decoration on the masked area. When using the above technology to decorate metal shells with complex structures, on the one hand, the process is long, resulting in a yield rate as low as less than 10%, increasing costs; on the other hand, the process requires a large amount of photosensitive ink and stripping chemicals, which may cause environmental pollution. Moreover, if three or more color effects are to be presented on the metal, repeated masking, exposure, and stripping are required, making large-scale processing difficult.

[0023] In addition, when the substrate has a complex shape, unnatural transitions such as color discontinuity may occur at locations where the shape changes.

[0024] In order to solve the problem that related technologies cannot simultaneously form continuous patterns on the bottom plate, frame and baffle of a metal shell, the present disclosure provides a metal shell, as shown in Figure 1, the metal shell 100 includes a bottom plate 110, a frame 120 and a baffle 130; wherein the frame 120 is arranged around the bottom plate 110, specifically, the frame 120 extends in the same direction around the bottom plate 110, and the baffle 130 is the end face of the frame 120.

[0025] In the present disclosure, the base plate 110, the frame 120, and the side bars 130 are all covered with a pattern layer; the pattern layer has nanopores, and the nanopores are filled with dye. As shown in Figures 1 and 2, the dye on the base plate, the frame, and the side bars forms a continuous pattern. The colors of any two of the patterns on the frame, the side bars, and the base plate are substantially the same; specifically, the color difference between them is approximately 2 or less.

[0026] The base plate, frame and baffle of the metal shell provided by the present invention are at least partially covered with a pattern layer having nanopores, and the nanopores are filled with dyes, so that the dyes on the base plate, frame and baffles form a continuous pattern, thereby realizing continuous decorative patterns in multiple areas of the metal shell, and the color difference value △E between any two of the baffles, frame and base plate is approximately less than 2, the colors between any two of the baffles, frame and base plate remain consistent, and the continuous pattern presents a uniform color.

[0027] In some embodiments of the present disclosure, a continuous pattern may include a single color block or multiple color blocks, and these color blocks may be distributed across the crossbar, border, and base. A "color block" refers to blocks of different colors formed by segmenting pixels or regions in an image or video according to certain rules. In this disclosure, a single color block refers to a block of the same color within a continuous pattern, while multiple color blocks refer to blocks of two or more colors within a continuous pattern. Specifically, the continuous pattern includes a first three-dimensional continuous monochrome color block, which includes a first region 131 located on the crossbar and a second region 121 located on the border. The dyes in the first region 131 and the second region 121 are identical, and the color difference ΔE between the first region 131 and the second region 121 is approximately 2 or less. This ensures that the pattern on the border and the pattern on the crossbar exhibit consistent color effects. "Approximately identical dyes" means that the type and content of the dyes are approximately the same. Of course, the dyes can also be completely identical, meaning that the type and content of the dyes are identical.

[0028] Color difference is a quantitative measure of the difference between two or more colors. The CIE Lab color space is often used as a standard for color difference calculations. In the CIE Lab color space, L represents the brightness of the color, a represents the axis from green to red, and b represents the axis from blue to yellow. Color difference is represented by ΔE, and its calculation formula is as follows:

[0029] Among them, △L, △a, and △b represent the difference between two colors on the L, a, and b axes respectively.

[0030] ΔE represents the color difference value in the Lab color space. The smaller the value, the smaller the color difference and the higher the color consistency. It is understood that the color difference ΔE in this disclosure refers to the color difference of the pattern with the same color on the gear bar, frame and bottom plate.

[0031] In some embodiments of the present disclosure, a third region 111 having the same dye as the first three-dimensional continuous color block is provided on the bottom plate, and the color difference value ΔE between any two of the first region 131, the second region 121, and the third region 111 is approximately less than 2. The nanopores on the bottom plate, the frame, and the bars of the metal housing provided by the present disclosure are filled with dye, so that the dye on the bottom plate, the frame, and the bars forms a continuous pattern, achieving a continuous decorative pattern in multiple areas of the metal housing. The color difference value ΔE between the bars and the frame having the same dye is less than 2, the colors of the bars and the frame remain consistent, and the continuous pattern presents a uniform color.

[0032] In some embodiments of the present disclosure, as shown in Figure 2, the continuous pattern on the base plate, frame, and stop bar may further include a continuous monochromatic color block different from the first three-dimensional continuous monochromatic color block. For example, the continuous pattern also includes a second three-dimensional continuous monochromatic color block adjacent to the first three-dimensional continuous monochromatic color block; the first three-dimensional continuous monochromatic color block and the second three-dimensional continuous monochromatic color block contain different dyes. Different dyes refer to different colors of the dyes. The base plate, frame, and stop bar each have a first three-dimensional continuous monochromatic color block and a second three-dimensional continuous monochromatic color block, enriching the diversity of decorative patterns on the metal shell surface.

[0033] In some embodiments of the present disclosure, the pattern on the frame is continuous with the pattern on the bar, and the pattern extending from the frame to the bar is free of breaks, omissions, or overlaps, resulting in high resolution. As shown in FIG3 , the second three-dimensional continuous color block includes a fourth region 132 on the bar and a fifth region 122 on the frame; the dyes in the fourth region 132 and the fifth region 122 are identical.

[0034] In some embodiments of the present disclosure, the intersection point of the boundary line 135 between the first area 131 and the fourth area 132 and the intersection point 134 between the block bar and the frame serves as the first intersection point; the intersection point 136 between the second area 121 and the fifth area 122 and the intersection point 134 between the block bar and the frame serves as the second intersection point, and the distance between the first intersection point and the second intersection point is less than 20 μm.

[0035] Specifically, as shown in Figure 2, the second three-dimensional continuous color block includes a sixth area 112 located on the base plate 110. The dyes in the sixth area 112, the fourth area 132, and the fifth area 122 are the same. In some embodiments of the present disclosure, the boundary line between the first area and the fourth area and the boundary line between the second area and the fifth area are all wavy lines. In the embodiments of the present disclosure, the boundary line between the first three-dimensional continuous monochrome color block and the second three-dimensional continuous monochrome color block is formed with regular raised wavy lines, making the transition between areas with different dyes more natural. Taking the stop bar as an example, as shown in Figure 4, the boundary line between the first area 131 and the third area 132 has continuous protrusions, and the shape is roughly a wavy line. Moreover, the orientation of the protruding parts of these continuous protrusions is related to the process of printing to form the pattern. Specifically, as shown in Figure 4, in some embodiments of the present disclosure, the width (d1) of the protrusions perpendicular to the direction in which the wavy lines extend is approximately 20-50 μm, and the width (d2) of the protrusions parallel to the direction in which the wavy lines extend is approximately 20-120 μm. Because the protrusions of the wavy lines are uniform in size, the continuous pattern presents a better visual effect.

[0036] Specifically, the width (d2) of the protrusions in the extending direction substantially parallel to the corrugation lines is about 30-50 μm.

[0037] In the present disclosure, the corrugated line includes a plurality of continuous protrusions; the coefficient of variation of the width (d1) of the protrusion perpendicular to the extension direction of the corrugated line is approximately less than 15%, and the coefficient of variation of the width (d2) of the protrusion parallel to the extension direction of the corrugated line is approximately less than 15%, that is, the corrugated line has uniform and continuous protrusions. The term "coefficient of variation" refers to the standard deviation divided by the mean value, and is used to describe the difference in the sizes of the plurality of continuous protrusions on the corrugated line. For example, the coefficient of variation of the width (d1) of the protrusion perpendicular to the extension direction of the corrugated line refers to the ratio of the standard deviation of the width (d1) of the protrusion perpendicular to the extension direction of the corrugated line to the mean value, and the coefficient of variation of the width (d2) of the protrusion parallel to the extension direction of the corrugated line refers to the ratio of the standard deviation of the width (d2) of the protrusion parallel to the extension direction of the corrugated line to the mean value.

[0038] Figure 5 is a partial structural diagram of the pattern on the metal shell provided by the related technology. As shown in Figure 5, the boundary edge between the first three-dimensional continuous monochrome color block and the second three-dimensional continuous monochrome color block is smooth, but due to technical problems in the exposure and development itself, ghosting will appear at the junction (as shown in the box), and the transition is unnatural.

[0039] The continuous pattern on the metal housing provided by the present disclosure is clear and has high resolution. For example, in some embodiments of the present disclosure, the resolution of the continuous pattern is approximately 300 dpi or higher, which can ensure the clarity of the printed pattern and obtain fine graphics on the metal housing, thereby enhancing the texture of the metal housing. In some embodiments, the resolution of the continuous pattern is approximately 400 dpi or higher.

[0040] In some embodiments, while ensuring the metallic texture of the metal shell, two-color and two-color gradient (inclusive) or more graphics can be realized within the range of 1mm×1mm. For example, the continuous pattern can be a color painting.

[0041] A second aspect of the present disclosure provides a method for preparing a metal casing, the method comprising the following steps:

[0042] S1. Anodizing a metal shell substrate to obtain a substrate having an anodized layer; the metal shell substrate includes a bottom plate, a frame, and a stop bar; and the anodized layer has nanopores;

[0043] S2, placing an elastic transfer film printed with a pattern on the substrate having the anodized layer so that the elastic transfer film covers the bottom plate, the frame and the stop bar, to obtain a film-attached substrate;

[0044] S3, assembling the film-laminated substrate in a mold and performing vacuuming, so that the elastic transfer film printed with the pattern is closely laminated to the substrate having the anodized layer, to obtain a pattern-laminated substrate;

[0045] S4, performing thermal transfer on the substrate with the pattern attached to obtain a transferred substrate;

[0046] S5, peeling off the film and sealing the pores of the transferred substrate.

[0047] The method provided by the present disclosure can simultaneously transfer and print a continuous pattern on the bottom plate, frame and baffle of the metal shell substrate, and the continuous pattern can extend from the frame to the baffle and from the frame to the bottom plate. The color difference value △E of the pattern with the same color is less than 2, the pattern has no broken lines, missing or interlaced lines, and the pattern has high resolution.

[0048] In some embodiments of the present disclosure, an anodic oxide layer is formed on the surface of the metal shell substrate by anodizing treatment. Specifically, the metal shell substrate can be one of aluminum alloy, magnesium alloy, steel matrix and titanium alloy.

[0049] Optionally, the conditions for the anodizing treatment include: using the metal shell substrate as the anode and performing anodizing treatment in a sulfuric acid solution; the conditions for the anodizing treatment include: a voltage of approximately 8-15V; a sulfuric acid concentration of approximately 100-200g / L; a time of approximately 30-60min; and a temperature of approximately 20-30°C.

[0050] In some embodiments, the D50 of the nanopores is approximately 1-1000 nm. The nanopores can accommodate and adsorb dye molecules that are thermally sublimated during the thermal transfer process, thereby forming a pattern on the surface of the metal shell substrate.

[0051] In some embodiments of the present disclosure, the substrate having the anodized layer is further subjected to a drying treatment to enhance the adsorption performance of the nanopores to dye molecules; specifically, the drying treatment conditions include: a drying temperature of approximately 80-100°C and a drying time of approximately 20-60 minutes.

[0052] In some embodiments, the drying temperature is about 90° C., and the drying time is about 40 minutes.

[0053] In some embodiments of the present disclosure, the elastic transfer film includes an elastic base film, a carrier film supported on the elastic base film, and a pattern printed on the carrier film using dye.

[0054] In some specific embodiments of the present disclosure, the elastic base film has a high elongation, can cover the bottom plate, frame and guard bar at the same time, and can maintain stable performance at the temperature of thermal transfer. Specifically, the elongation of the elastic base film is about 100-900%. Among them, the elastic base film can be a PET film, a PC film or a PE film. Since the elastic base film needs to have a high elongation, and the PET film also has small adhesion changes over time and stable performance, clear patterns can be printed on it. Specifically, the elastic base film is a PET film, for example, the elastic base film is a PET film with a molecular weight of 10,000-100,000.

[0055] In some embodiments, the stretchability of the elastic basement membrane is approximately 200-300%.

[0056] In some embodiments of the present disclosure, the carrier film is used to load the dye and prevent the dye from lateral diffusion during thermal transfer, thereby ensuring high resolution of the transferred pattern. Optionally, the carrier film is a PVA film layer, and the thermal sublimation dye is printed on the PVA film layer using a digital printer. During the thermal transfer process, the dye stored on the PVA film layer is adsorbed by the nanopores on the surface of the metal shell substrate, forming a clear and continuous pattern on the bottom plate, frame and bar of the metal shell. Specifically, the thickness of the carrier film is approximately 5-100 μm, which is conducive to storing the dye and facilitating the close adhesion of the elastic transfer film to the substrate. The PVA film layer and the elastic base film cooperate to ensure that the pattern transferred to the metal shell substrate has the above-mentioned high resolution.

[0057] In some embodiments, the carrier film has a thickness of approximately 20-40 μm.

[0058] In some embodiments of the present disclosure, the dye has thermal sublimation properties and can be adsorbed by nanopores on the surface of the metal housing substrate. Specifically, the molecular diameter of the dye is no greater than 5 nm, and the sublimation temperature of the dye is approximately 100° C. to 200° C. In some embodiments of the present disclosure, the dye is an azo dye.

[0059] In some embodiments, the dye has a sublimation temperature of about 120-160°C.

[0060] In the present disclosure, the transfer printing is performed by assembling the film-laminated substrate in a mold capable of forming a sealed structure, wherein the mold includes a base, a frame, and a contoured jig.

[0061] The profiling jig 200 is used to profile the metal shell. As shown in FIG6 , the profiling jig 200 includes a first plane for contacting the metal shell and a second plane 210 opposite the first plane. As shown in FIG7 , when the metal shell 100 and the profiling jig 200 are mated, the second plane of the profiling jig 200 protrudes above the metal shell. A spacing B1 (see FIG6 ) exists between the outer contour of the profiling jig and the inner surface of the metal shell. B1 is approximately 0.5-40 mm. Specifically, the vertical distance A1 between the second plane and the stop bar is approximately 1-100 mm. Due to the gap between the second plane and the stop bar, when the mold is vacuumed, the outer contours of the metal shell's base, frame, stop bar, and profiling jig are covered and tightly fitted by the patterned elastic transfer film. Thus, after thermal transfer, the dye in the pattern is adsorbed into the nanopores formed on the base, frame, and stop bar of the metal shell.

[0062] In some embodiments, B1 is approximately 0.5-10 mm. A1 is approximately 5-20 mm. When the vertical distance A1 is too small, the elastic transfer film cannot effectively cover the metal shell during vacuuming, which may result in the inability to form a pattern on the frame and the bar of the metal shell. When the vertical distance A1 is too large, the elastic transfer film's covering effect on the metal shell is reduced, and the elastic transfer film may shift, resulting in reduced transfer quality. Specifically, the vertical distance A1 can be 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 12 mm, 14 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm, or any value within the aforementioned range.

[0063] In some embodiments of the present disclosure, the spacing B1 between the outer contour of the profiling jig 200 and the inner surface of the metal shell is approximately 0.5-40 mm (see Figure 6). Since the frame and the base form a closed structure when they are buckled together and between the base and the elastic transfer film, there is a gap between the metal shell and the outer contour of the profiling jig, and the elastic base film has a high elongation rate, which facilitates the elastic transfer film to better cover the block bar as a whole when vacuuming, thereby achieving the simultaneous formation of continuous patterns on multiple surfaces of the metal shell. If the spacing B1 is too small, the elastic transfer film cannot cover the block bar, resulting in the inability to form a pattern on the block bar. If the spacing B1 is too large, the accuracy of the transfer may decrease. Specifically, the spacing B1 can be 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm, 25mm, 30mm, 35mm, 40mm or any value within the above range.

[0064] As shown in Figure 8, the base 300 includes a storage space for the substrate and the profiling jig, and the frame 400 cooperates with the base 300 to form a sealed structure. Specifically, the base 300 and the frame 400 are detachably connected, specifically, a snap-fit ​​connection. In a specific embodiment, the base includes a base and a side frame that can be combined with the base to form a storage space. The side frame has a groove on the end surface that can engage with the frame. The base and frame can be engaged by placing the base and frame opposite each other and applying pressure to the frame or the base.

[0065] As shown in Figure 8, the base's thickness, Y1, is roughly greater than the sum of the thickness of the profiling fixture and the thickness of the metal shell (i.e., Y1 > A1 + metal shell thickness). This facilitates placement of the frame within the base and its subsequent engagement with the base during subsequent processing. The thickness of the metal shell refers to the thickness of the base plate.

[0066] In a specific embodiment, the thickness X1 of the frame is approximately 5-50 mm.

[0067] Specifically, in some embodiments of the present disclosure, an exhaust air duct is provided in the base, which can be used to connect a vacuum pumping device. When the elastic transfer film printed with a pattern is tightly fitted to the substrate having an anodized layer, the vacuum degree in the mold is less than or equal to -0.1 MPa (gauge pressure), and the bottom plate, frame and baffle of the metal shell are all covered, so that the elastic transfer film printed with a pattern is tightly fitted to the substrate having an anodized layer.

[0068] In some embodiments of the present disclosure, the conditions for the thermal transfer include: a heating temperature of approximately 80-240° C., and a heating time of approximately 2-360 minutes.

[0069] Specifically, when using the jig of the embodiment of the present invention to perform thermal transfer on the metal shell substrate, the metal shell substrate is placed on the contoured jig, and then the elastic transfer film printed with a pattern is covered on the surface of the metal shell with the anodized layer, and the elastic transfer film is covered on all sides of the base substrate, the frame and the base are relative to each other and pressure is applied to the frame or the base to make the frame and the base engage, the frame is sealed together with the base and the elastic transfer film to form a sealing structure, the mold is vacuumed through the exhaust air duct provided on the base, and the mold is heated at the same time, the dye on the elastic transfer film is sublimated by the heat and adsorbed by the nanopores in the anodized layer of the metal shell, and the dye is sealed in the nanopores through sealing treatment.

[0070] In some embodiments of the present disclosure, the sealing can be achieved by the following method: the substrate after the film is removed is transferred into a sealing agent for immersion sealing; the sealing conditions include: the sealing agent is about 5-10wt% nickel acetate solution, the immersion temperature is about 80-100°C, and the immersion time is about 10-30min.

[0071] The present disclosure also provides an electronic terminal product, which includes the aforementioned metal housing. The electronic terminal product may be a smart phone or a tablet computer.

[0072] The present disclosure is further described in detail below through examples, but the present disclosure is not limited to the following examples.

[0073] Example 1

[0074] The method for preparing the metal shell in this embodiment includes the following steps:

[0075] (1) Use degreasing agent, rust remover and water to clean the surface of the aluminum alloy metal shell substrate to expose the bright metal surface of the metal shell substrate, and then bake it at 90 degrees for 30 minutes;

[0076] (2) performing an anodizing treatment on the metal shell substrate to obtain a metal shell substrate having an anodized layer; the anodizing treatment conditions are: a voltage of approximately 8-15V; a sulfuric acid concentration of approximately 100-200g / L; a time of approximately 30-60min; a temperature of approximately 20-30°C; and a diameter of nanopores in the anodized layer of approximately 20nm;

[0077] (3) The metal shell substrate with an anodized layer is placed in a base with a profiling jig, and the vertical distance A1 between the second plane and the stop bar is approximately 15 mm. The spacing B1 between the outer contour of the profiling jig 200 and the inner surface of the metal shell is approximately 6 mm. Then, an elastic transfer film printed with a pattern is placed on the metal shell substrate with an anodized layer, and the resolution of the pattern printed on the elastic transfer film is approximately 400 dpi. The frame and the base are combined and fastened, and the air is evacuated to approximately -0.1 MPa through the air duct of the base. The elastic transfer film is covered with the bottom plate, the frame and the stop bar to obtain a film-attached substrate. The elastic transfer film includes an elastic base film, a carrier film loaded on the elastic base film, and a pattern printed on the carrier film using a dye. The elastic base film is a PET film with a stretch ratio of approximately 200%, the carrier film is a PVA coating with a thickness of approximately 50 μm, and the dye is an azo dye with a thermal sublimation temperature of approximately 90°C and a dye molecule diameter of approximately 5 nm. The dye can be selected according to actual needs.

[0078] (4) heating the jig to approximately 140° C. for approximately 800 s to obtain the transferred substrate;

[0079] (5) After the transferred substrate is naturally cooled to room temperature, the metal shell substrate is taken out, the elastic transfer film on the surface of the metal shell substrate is removed, and the substrate is immersed in an approximately 6wt% nickel acetate solution for sealing. The immersion temperature is approximately 80°C and the immersion time is approximately 20 minutes. The substrate is then taken out and cleaned to obtain a metal shell decorated with a three-dimensional pattern, which is marked as S1.

[0080] Example 2

[0081] The method for preparing the metal shell in this embodiment is the same as that in Example 1, except that the thickness of the PVA coating is approximately 2 μm. The obtained metal shell is marked as S2.

[0082] Example 3

[0083] The method for preparing the metal shell in this embodiment is the same as that in Example 1, except that the thickness of the PVA coating is approximately 100 μm. The obtained metal shell is marked as S3.

[0084] Example 4

[0085] The method for preparing the metal shell in this embodiment is the same as that in Example 1, except that the thickness of the PVA coating is approximately 120 μm. The obtained metal shell is marked as S4.

[0086] Example 5

[0087] The method for preparing the metal shell in this embodiment is the same as that in embodiment 1, except that the elastic base film is a PET film with a stretchability of approximately 100%, and the obtained metal shell is marked as S5.

[0088] Example 6

[0089] The method for preparing the metal shell in this embodiment is the same as that in embodiment 1, except that the elastic base film is a PET film with a stretching rate of approximately 500%. The obtained metal shell is marked as S6.

[0090] Example 7

[0091] The method for preparing the metal shell in this embodiment is the same as that in embodiment 1, except that the elastic base film is a PET film with an elongation of approximately 800%, and the obtained metal shell is marked as S7.

[0092] Example 8

[0093] The method for preparing the metal shell in this embodiment is the same as that in embodiment 1, except that the elastic base film is a PET film with an elongation of approximately 950%, and the obtained metal shell is marked as S8.

[0094] Example 9

[0095] The method for preparing the metal shell in this embodiment is the same as that in embodiment 1, except that the vertical distance A1 between the second plane and the stop bar is approximately 0.5 mm. The obtained metal shell is marked as S9.

[0096] Example 10

[0097] The method for preparing the metal shell in this embodiment is the same as that in embodiment 1, except that the vertical distance A1 between the second plane and the stop bar is approximately 50 mm. The obtained metal shell is marked as S10.

[0098] Example 11

[0099] The method for preparing the metal shell in this embodiment is the same as that in embodiment 1, except that the vertical distance A1 between the second plane and the stop bar is approximately 100 mm. The obtained metal shell is marked as S11.

[0100] Example 12

[0101] The method for preparing the metal shell in this embodiment is the same as that in embodiment 1, except that the vertical distance A1 between the second plane and the stop bar is approximately 110 mm. The obtained metal shell is marked as S12.

[0102] Example 13

[0103] The method for preparing the metal shell in this embodiment is the same as that in embodiment 1, except that the distance B1 between the outer contour of the profiling jig 200 and the inner surface of the metal shell is approximately 0.1 mm. The obtained metal shell is marked as S13.

[0104] Example 14

[0105] The method for preparing the metal shell in this embodiment is the same as that in embodiment 1, except that the distance B1 between the outer contour of the profiling jig 200 and the inner surface of the metal shell is approximately 20 mm. The obtained metal shell is marked as S14.

[0106] Example 15

[0107] The method for preparing the metal shell in this embodiment is the same as that in embodiment 1, except that the distance B1 between the outer contour of the profiling jig 200 and the inner surface of the metal shell is approximately 40 mm. The obtained metal shell is marked as S15.

[0108] Example 16

[0109] The method for preparing the metal shell in this embodiment is the same as that in embodiment 1, except that the distance B1 between the outer contour of the profiling jig 200 and the inner surface of the metal shell is approximately 45 mm. The obtained metal shell is marked as S16.

[0110] Example 17

[0111] The method for preparing the metal housing in this embodiment is the same as that in embodiment 1, except that the resolution of the printed pattern is approximately 200 dpi. The obtained metal housing is marked as S17.

[0112] Example 18

[0113] The method for preparing the metal housing in this embodiment is the same as that in embodiment 1, except that the resolution of the printed pattern is approximately 1000 dpi. The obtained metal housing is marked as S18.

[0114] Example 19

[0115] The method for preparing the metal housing in this embodiment is the same as that in embodiment 1, except that the resolution of the printed pattern is approximately 5000 dpi. The obtained metal housing is marked as S19.

[0116] Comparative Example 1

[0117] The method for preparing the metal shell in this comparative example includes the following steps:

[0118] (1) spraying a layer of photosensitive coating on the surface of the metal shell substrate;

[0119] (2) exposing the metal shell substrate three times through partial shielding, the first exposure being the bottom plate, the second exposure being the frame, and the third exposure being the stop bar;

[0120] (3) Remove the photosensitive coating at the shielding position by using a developing solution to achieve partial shielding;

[0121] (4) performing a first anodizing treatment on the unmasked area to provide decorative coloring;

[0122] (5) Stripping the coating of the local shielding area;

[0123] (6) A second anodizing treatment is performed on the partially shielded area for decorative coloring, and the resulting metal shell is marked as D1.

[0124] Performance testing:

[0125] (1) Appearance evaluation criteria are as follows:

[0126] a. The base plate, frame and bar are evenly colored, and the color difference standard of the same dye is △E1≤2;

[0127] Among them, the calculation formula of △E1 is: The specific values ​​of △L, △a, and △b in the formula can be obtained by testing with an X-Rite colorimeter.

[0128] b. The continuous three-dimensional single color block extending from the bottom plate to the side edge of the frame and the stop bar maintains continuity without any breakage, missing lines, or intersections. That is, the intersection point 135 between the first area 131 and the fourth area 132 and the intersection point 134 between the stop bar and the frame serves as the first intersection point; the intersection point 136 between the second area 121 and the fifth area 122 and the intersection point 134 between the stop bar and the frame serves as the second intersection point. The maximum distance d between the first intersection point and the second intersection point is approximately ≤20 μm under a microscope.

[0129] c. There is no ghosting on the boundary line between different color blocks of the bottom plate, frame and barrier strip, no obvious and discontinuous protrusions, and there are uniform and continuous protrusions, wherein the width (d1) of the protrusion perpendicular to the extension direction of the corrugated line is approximately 20-50μm, and the coefficient of variation of the width (d1) of the protrusion perpendicular to the extension direction of the corrugated line is approximately less than 15%; the width (d2) of the protrusion parallel to the extension direction of the corrugated line is approximately 20-120μm, and the coefficient of variation of the width (d2) of the protrusion parallel to the extension direction of the corrugated line is approximately less than 15%.

[0130] Specifically, the width (d2) of the protrusion in the extension direction parallel to the corrugation line is about 30-50 μm.

[0131] The appearance evaluation results of the metal shells S1-S19 and the metal shell D1 are shown in Table 1.

[0132] Table 1

[0133] According to Table 1, the continuous pattern on the surface of the metal shell provided by the present disclosure can present a uniform color, and the continuous three-dimensional single color block extending from the bottom plate to the side of the frame and the guard bar maintains continuity without breakage, missing or interlacing.

[0134] During the processing, it was also discovered that controlling the vertical distance A1 between the second plane of the profiling jig and the stop bars further improved the uniformity of the coloring of the frame and stop bars; and controlling the distance B1 between the outer contour of the profiling jig and the inner surface of the metal shell further improved the uniformity of the coloring of the frame and stop bars. However, in Comparative Example 1, due to the use of exposure and development methods to form the pattern, there was a ghosting at the pattern boundary, resulting in an unnatural pattern transition.

[0135] (2) Salt spray test: In a closed environment at a temperature of approximately 35°C and a relative humidity of approximately 90%, the surface of the aluminum alloy metal shell was continuously sprayed with salt water using a NaCl solution with a pH of approximately 6.5-7.2 and a weight percentage of approximately 5% for approximately 2 hours. The air pressure was approximately 10-25 psi and the spray rate was approximately 0.75-3 cc / 80 cm2 / hr. After the spraying, the metal shell was transferred to a storage box at a temperature of approximately 40°C and a relative humidity of approximately 80% for approximately 96 hours. The metal shell was removed and allowed to recover at room temperature for approximately 2 hours before inspection. After approximately 96 hours, the pattern on the surface of the aluminum alloy metal shell was intact, indicating that the pattern was completely adsorbed into the nanopores.

[0136] (3) Solar radiation test: Use tinfoil to cover half of the area to be tested of the metal shell to be tested, and place the metal shell to be tested in a xenon lamp test chamber. The test chamber temperature is set to about 40°C, the lamp is about 340nm, the band irradiance is about 0.55W / M2, and the wavelength range is about 300-800nm. Keep it for about 20 hours, and then turn off the solar radiation source for about 4 hours. The above is one cycle, and 3 cycles are performed for a total of about 72 hours of testing; then take out the metal shell, wait for the metal shell to return to room temperature, check the appearance of the paint coating of the metal shell, and use a colorimeter to perform a color difference test on the irradiated aging area and the tinfoil-shielded area of ​​the test metal shell.

[0137] Judgment requirements: No abnormality in appearance, no falling off, no cracks, no visual color difference, color difference value △E2≤5.0; adhesion meets 4B requirements.

[0138] Adhesion judgment criteria:

[0139] 5B: None fell off;

[0140] 4B: A small amount of coating peels off, with an area not exceeding 5%;

[0141] 3B: The coating is peeling off, the area is greater than 5% but not more than 15%;

[0142] 2B: Large fragments have fallen off, covering an area greater than 15% but not greater than 35%;

[0143] 1B: Large fragments have peeled off, with an area greater than 35% but not greater than 65%;

[0144] 0B: The degree of peeling exceeds 1B.

[0145] The results of the salt spray test and solar radiation test of metal shells S1-S19 and metal shell D1 are shown in Table 2.

[0146] Table 2

[0147] As shown in Table 2, it can be seen from the examples and comparative examples that the metal shell provided by the present disclosure has the same excellent wear resistance and corrosion resistance as the conventional process.

[0148] The embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the scope of protection of the present disclosure.

[0149] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0150] In addition, the various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A metal housing (100), wherein: The metal shell (100) comprises a bottom plate (110), a frame (120) and a stop bar (130); the bottom plate (110), the frame (120) and the stop bar (130) are at least partially covered with a pattern layer, the pattern layer comprising nanopores; the nanopores are filled with dyes; the dyes on the bottom plate (110), the frame (120) and the stop bar (130) form a continuous pattern; the colors of any two of the patterns on the frame (120), the pattern on the stop bar (130) and the pattern on the bottom plate (110) are substantially the same.

2. The metal housing (100) according to claim 1, wherein: The color difference value ΔE between any two of the pattern on the frame (120), the pattern on the stop bar (130), and the pattern on the bottom plate (110) is less than approximately 2.

3. The metal housing (100) according to claim 1 or 2, wherein: The pattern layer comprises an anodic oxide film provided on the bottom plate (110), the frame (120) and the stop bar (130); the anodic oxide film has the nanopores, and the anodic oxide film is covered with a sealing film.

4. The metal housing (100) according to any one of claims 1 to 3, wherein: The continuous pattern comprises a first three-dimensional continuous monochrome color block, wherein the first three-dimensional continuous monochrome color block comprises a first area (131) located on the stop bar (130) and a second area (121) located on the frame (120); the dyes in the first area (131) and the second area (121) are the same, and the color difference value ΔE between the first area (131) and the second area (121) is less than 2.

5. The metal housing (100) according to claim 4, wherein: The first three-dimensional continuous monochrome color block includes a third area (111) located on the base plate (110), and a color difference value ΔE between any two of the first area (131), the second area (121) and the third area (111) is less than approximately 2.

6. The metal housing (100) according to claim 4 or 5, wherein: The continuous pattern also includes a second three-dimensional continuous monochrome color block adjacent to the first three-dimensional continuous monochrome color block; the dyes in the first three-dimensional continuous monochrome color block and the second three-dimensional continuous monochrome color block are different from each other; the second three-dimensional continuous color block includes a fourth area (132) located on the stop bar (130) and a fifth area (122) located on the frame (120); the dyes in the fourth area (132) and the fifth area (122) are substantially the same.

7. The metal housing (100) according to claim 6, wherein: The metal shell (100) has a first intersection and a second intersection, the first intersection being the intersection of a boundary line between the first region (131) and the fourth region (132) and a boundary line between the stop bar (130) and the frame (120); The second intersection point is the intersection point of the boundary line between the second area (121) and the fifth area (122) and the boundary line between the stop bar (130) and the frame (120); The distance between the first intersection and the second intersection is approximately less than 20 μm.

8. The metal housing (100) according to claim 7, wherein: The distance between the first intersection point and the second intersection point is approximately 10-15 μm.

9. The metal housing (100) according to any one of claims 6 to 8, wherein: The boundary line between the first region (131) and the fourth region (132) and the boundary line between the second region (121) and the fifth region (122) are both roughly corrugated lines.

10. The metal housing (100) according to claim 9, wherein: The corrugated line includes a plurality of continuous protrusions; the coefficient of variation of the width (d1) of the protrusions roughly perpendicular to the extension direction of the corrugated line is approximately less than 15%, and the coefficient of variation of the width (d2) of the protrusions roughly parallel to the extension direction of the corrugated line is approximately less than 15%.

11. The metal housing (100) according to claim 10, wherein: The width (d1) of the protrusion perpendicular to the extension direction of the corrugated line is about 20-50 μm; the width (d2) of the protrusion roughly parallel to the extension direction of the corrugated line is about 20-120 μm.

12. The metal housing (100) according to claim 11, wherein: The protrusions are substantially parallel to the extending direction of the corrugated lines and have a width (d2) of about 30-50 μm.

13. The metal housing (100) according to any one of claims 1 to 12, wherein: The resolution of the continuous pattern is approximately above 300 dpi.

14. The metal housing (100) according to claim 13, wherein: The resolution of the continuous pattern is approximately above 400 dpi.

15. A method for preparing a metal shell, wherein: The method comprises the following steps: Anodizing the metal shell substrate to obtain a substrate having an anodized layer; the metal shell substrate includes a bottom plate (110), a frame (120) and a stop bar (130); the anodized layer has nanopores; Placing an elastic transfer film printed with a pattern on the substrate having the anodized layer so that the elastic transfer film covers the bottom plate (110), the frame (120) and the stop bar (130), thereby obtaining a film-attached substrate; Assembling the film-laminated substrate in a mold and performing vacuuming to ensure that the elastic transfer film printed with the pattern is closely laminated to the substrate having the anodized layer, thereby obtaining a pattern-laminated substrate; Thermally transferring the pattern-attached substrate to obtain a transferred substrate; The transferred substrate is peeled off and the holes are sealed.

16. The method according to claim 15, wherein The elastic transfer film includes an elastic base film, a carrier film supported on the elastic base film, and a pattern printed on the carrier film using dye.

17. The method according to claim 16, wherein The stretching rate of the elastic base film is about 100-900%; the elastic base film is a PET film.

18. The method according to claim 17, wherein The stretchability of the elastic base film is approximately 200-300%.

19. The method according to any one of claims 16 to 18, wherein: The carrier film is a PVA film layer; The thickness of the carrier film is approximately 5-100 μm.

20. The method according to claim 19, wherein The thickness of the carrier film is approximately 20-40 μm.

21. The method according to any one of claims 16 to 20, wherein: The molecular diameter of the dye is approximately no greater than 5 nm; The sublimation temperature of the dye is approximately 100-200°C.

22. The method according to claim 21, wherein The molecular diameter of the dye is approximately no greater than 3 nm; The sublimation temperature of the dye is approximately 120-160°C.

23. The method according to any one of claims 16 to 22, wherein: The dye is an azo dye.

24. The method according to any one of claims 15 to 23, wherein: The mold comprises a contoured jig (200), wherein the contoured jig (200) comprises a first plane for contacting a substrate and a second plane (210) opposite to the first plane; When the film-laminated substrate is assembled in the mold, the spacing (B1) between the stop bar (130) and the outer contour of the contoured jig (200) is approximately 0.5-40 mm, and the vertical distance (A1) between the second plane (210) and the stop bar (130) is approximately 1-100 mm.

25. The method according to claim 24, wherein The spacing (B1) between the stop bar (130) and the outer contour of the contoured jig (200) is approximately 0.5-10 mm, and the vertical distance (A1) between the second plane (210) and the stop bar (130) is approximately 5-20 mm.

26. The method according to claim 25, wherein A vertical distance (A1) between the second plane (210) and the stop bar (130) is approximately 8 mm.

27. The method according to any one of claims 15 to 26, wherein: When the elastic transfer film printed with a pattern is tightly attached to the substrate having the anodized layer, the vacuum degree in the mold is less than or equal to -0.1 MPa.

28. The method according to any one of claims 15 to 76, wherein The conditions for the thermal transfer include: a heating temperature of approximately 80-240° C., and a heating time of approximately 2-360 minutes.

29. The method according to claim 28, wherein The heating temperature is about 120-180°C, and the heating time is about 5-15 minutes.

30. The method according to any one of claims 15 to 29, wherein The method further comprises drying the substrate having the anodized layer; The drying conditions include: a drying temperature of approximately 80-100° C., and a drying time of approximately 20-60 minutes.

31. The method according to claim 30, wherein The drying temperature is about 90°C and the drying time is about 40 minutes.

32. An electronic terminal product, wherein: The electronic terminal product comprises the metal housing (100) according to any one of claims 1 to 14.

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