CN107396562B

CN107396562B - Surface processing method of shell, shell and mobile terminal

Info

Publication number: CN107396562B
Application number: CN201710647589.8A
Authority: CN
Inventors: 张维; 林四亮
Original assignee: Vivo Mobile Communication Co Ltd
Current assignee: Vivo Mobile Communication Co Ltd
Priority date: 2017-08-01
Filing date: 2017-08-01
Publication date: 2020-07-31
Anticipated expiration: 2037-08-01
Also published as: CN107396562A

Abstract

The embodiment of the invention provides a surface processing method of a shell, the shell and a mobile terminal, wherein the outer surface of the shell comprises a middle part and an edge part, the middle part is a plane, and the surface processing method comprises the following steps: performing physical sand blasting treatment on the outer surface of the shell; and carrying out chemical sand blasting treatment on the outer surface of the shell by using a first corrosion solution. The sand power and the angle that the circular arc department of casing border received change gradually, and the border that is not sprayed by the physics sandblast in the casing forms exquisite sand sense for the sandblast feel of casing is from thick to thin, and the glossiness is from dumb to bright gradual change, and sand sense and glossiness change along with the radian change at the border of casing, and the gradual change effect is excessive natural.

Description

Surface processing method of shell, shell and mobile terminal

Technical Field

The invention relates to the technical field of communication, in particular to a shell surface processing method, a shell and a mobile terminal.

Background

With the rapid development of various technologies of the mobile terminal, the demand of a user on the mobile terminal is higher and higher, and meanwhile, the demand on the experience of the mobile intelligent terminal is higher and higher.

At present, the shell of the mobile terminal mainly comprises a metal material and a plastic material, and for the shell made of the metal material, an anodic oxidation process is usually used during sand blasting, the sand blasting is uniform, and the shell has a single effect.

Disclosure of Invention

The embodiment of the invention provides a shell surface processing method, a shell and a mobile terminal, and aims to solve the problem of single shell effect caused by uniform sand blasting.

In a first aspect, a surface processing method for a shell is provided, where an outer surface of the shell includes a middle portion and an edge portion, the middle portion is a plane, and the surface processing method includes:

performing physical sand blasting treatment on the outer surface of the shell;

and carrying out chemical sand blasting treatment on the outer surface of the shell by using a first corrosion solution.

In a second aspect, a shell is provided, where an outer surface of the shell includes a middle portion and a rim portion, the middle portion is a plane, and the rim portion extends inward from an edge of the middle portion and forms an arc shape; the edge part comprises an upper edge part and a lower edge part, and the upper edge part is connected with the middle part;

the middle part of the outer surface of the shell and the upper part of the edge are provided with a first concave-convex structure;

the outer surface of the shell is provided with a second concave-convex structure;

the distribution density of the first concave-convex structure is gradually reduced from the middle part of the shell to the edge part, and the distribution density of the second concave-convex structure is greater than that of the first concave-convex structure in the middle part of the outer surface of the shell.

In a third aspect, a mobile terminal is provided, which comprises the above-mentioned housing.

Thus, in the embodiment of the invention, the outer surface of the shell is subjected to physical sand blasting, the outer surface of the shell is subjected to chemical sand blasting by using a corrosive solution, the strength and the angle of sand received at the arc of the edge of the shell are gradually changed, and the edge which is not subjected to physical sand blasting in the shell forms fine sand feeling, so that the sand blasting texture of the shell is gradually changed from coarse to fine, the glossiness is gradually changed from matte to bright, in addition, the sand feeling and the glossiness are changed along with the radian change of the edge of the shell, and the gradual change effect is excessively natural.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments of the present invention will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without inventive labor.

Fig. 1 is a flowchart of a method for processing a surface of a housing according to an embodiment of the present invention.

Fig. 2A is a schematic structural view of an unabraded enclosure in accordance with an embodiment of the present invention.

Fig. 2B is a schematic structural diagram of an edge of a housing according to an embodiment of the invention.

Fig. 3 is a schematic illustration of a grit blast in accordance with an embodiment of the present invention.

Fig. 4 is a schematic view of a configuration of a shell after sandblasting in accordance with an embodiment of the present invention.

Fig. 5 is a flowchart of a method for finishing a surface of a housing according to an embodiment of the present invention.

Fig. 6 is a schematic structural diagram of a housing according to an embodiment of the present invention.

Fig. 7 is a schematic structural diagram of a mobile terminal according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

First embodiment

Referring to fig. 1, a flow chart of a method for surface processing of a housing according to an embodiment of the present invention is shown.

In the embodiment of the invention, the shell can be made of metal material; alternatively, only the outer surface of the shell may be made of metal. The metal material may be aluminum alloy or the like. In practical application, the shell can be used as a shell of a mobile terminal such as a mobile phone, a tablet personal computer and intelligent wearable equipment (such as a bracelet and a watch), such as a rear cover.

As shown in fig. 2A, the outer surface of the housing 200 includes a middle portion 201 and a rim portion 202, wherein the middle portion 201 is a plane, and the rim portion 202 (a portion in a dotted circle) extends inward from an edge of the middle portion 201 and forms a circular arc shape so as to extend to the inner surface of the housing 200.

For example, if the middle portion 201 is oriented upward, the rim portion 202 is curved downward; the middle portion and the edge are relative positions, that is, positions on two sides of the middle portion are edges, and a person skilled in the art can determine the middle portion and the edges of the shell according to actual situations.

The above-mentioned case with a flat middle part does not necessarily mean a flat surface, and the case with a flat middle part can be adjusted according to the characteristics of the product in different products. For example, if the housing is a rear cover of a mobile terminal, since the rear cover needs to be hollowed to expose components such as a camera, a fingerprint sensor, a color temperature sensor, etc., the edges of the through holes formed in the rear cover may be slightly raised.

Further, as shown in fig. 2A, the rim portion 202 of the outer surface of the casing 200 may include an upper rim portion 2021 and a lower rim portion 2022, and the upper rim portion 2021 is directly connected to the middle portion 201.

As shown in FIG. 2B, the included angle between the tangent of the arc at the upper portion of the edge and the horizontal line of the middle portion 201 is α, and α is not more than 90 degrees, and the included angle between the tangent of the arc at the lower portion of the edge and the horizontal line of the middle portion 201 is β, and β is more than 90 degrees.

The surface processing method of the shell specifically comprises the following steps:

step 101, performing physical sand blasting on the outer surface of the shell.

The physical sand blasting treatment is to form a high-speed jet beam by using compressed air as power, and to spray abrasive (such as copper ore, quartz sand, carborundum, iron sand, Hainan sand and other sand grains) to the surface of a shell needing physical treatment at a high speed so as to change the appearance or shape of the outer surface of the shell.

Due to the impact and cutting action of the abrasive on the surface of the shell, the outer surface of the shell can obtain certain cleanliness and different roughness, the mechanical property is improved, the fatigue resistance of the shell is improved, the adhesive force between the shell and a coating is increased, the durability of a coating film on the surface of the shell is prolonged, and the leveling and decoration of the coating are facilitated.

In one example of the embodiment of the present invention, the above-mentioned physical blasting is preferably performed on zircon sand having a particle size range of 170# -205#, and the pressure of the blasting gun is 0.6KG/cm²-1.6KG/cm²And the sand blasting time is 30-60 s. Preferably, the physical sand blasting adopts 205# zircon sand and the pressure of a spray gunThe force is 1.2KG/cm²The blasting time was 30 s.

In a specific implementation, as shown in fig. 3, the outer surface of the housing 300 is polished, and then the spray gun 310 is disposed above the middle portion 301 of the outer surface of the housing, that is, the polished housing 300 is disposed below the spray gun 310.

The spray gun 310 sprays an abrasive (e.g., sand) to the middle portion 301 of the outer surface of the housing, the abrasive (e.g., sand) impacts and cuts the outer surface of the housing, and the middle portion 301 and the upper edge portion 3021 of the outer surface of the housing form the first concavo-convex structure 303, and the plurality of first concavo-convex structures 303 exhibit a uniform and fine first frosting feeling. The first concave-convex structure 303 is formed by impact cutting of zircon sand in the above-described preferred particle size range, and the formed first concave-convex structure 303 is relatively fine.

It should be noted that the range of the spray gun 310 may directly cover the upper rim portion 3021, but not the lower rim portion 3022. Therefore, the distribution range of the first concave-convex structure 303 is included in the middle portion 301 and the edge upper portion 3021. Of course, the lower rim portion 3022 may also have a small amount of the first concave-convex structure 303 distributed thereon due to air flow reflection and the like.

In practical application, the pressure of the spray is maximum at the position right below the spray gun, and the pressure of the spray is gradually reduced from the position to the edge, so that the distribution density of the first concave-convex structure 303 on the outer surface of the shell is gradually reduced from the middle part of the shell to the edge part.

Because the spray gun is arranged right above the middle part of the shell, the spray pressure of the spray gun to the middle part 301 of the shell is basically consistent, and therefore, the density of the first concave-convex structure 303 distributed in the middle part 301 of the shell is basically consistent, namely, the density of the concave-convex structure 303 is in a uniform density range. The pressure of the spray gun on the rim portion 302 gradually decreases, and the impact force of sand particles on the rim upper portion 3021 of the casing starts to decrease, so that the density of the first concave-convex structure 303 distributed on the rim upper portion 3021 starts to decrease, and the second frosting feeling presented on the rim upper portion 3021 is relatively weak. The lower part 3022 of the edge of the shell is positioned where the spray gun can not spray, so that the effect of the smooth surface can be maintained. Thus, the outer surface of the whole shell can have the effect of gradually changing the sand surface to the smooth surface from the middle part to the edge part, and particularly, the performance of the edge part 302 is obvious.

After the step of physically blasting sand is completed, closing the spray gun and removing the batch of shells; the next batch of shells are arranged to be placed under the spray gun, and the next batch of physical sand blasting is started, so that batch production can be realized, and the production efficiency is improved.

And 102, performing chemical sand blasting treatment on the outer surface of the shell by using a first etching solution.

The chemical sand blasting is to etch a fine second concave-convex structure on the surface of the shell by using an etching solution.

In a specific implementation, the shell is soaked in the first corrosion solution, and the outer surface of the shell forms a second concave-convex structure.

In one example of an embodiment of the present invention, the first etching solution is sodium nitrate (NaNO)₃) Mixed with sodium hydroxide (NaOH), sodium nitrate (NaNO)₃) The volume ratio of the chemical sand blasting agent to sodium hydroxide (NaOH) is 4:1-6:1, the temperature of the chemical sand blasting is 70-85 ℃, and the time of the chemical sand blasting is 30-50 s.

In a specific implementation, the second relief structure is distributed with a density greater than the density of the first relief structure in the middle of the outer surface of the shell, i.e. the second relief structure formed by chemical blasting is smaller than the first relief structure formed by physical blasting, typically about one tenth of the first particles.

For example, the diameter of the first concavo-convex structure formed under physical blasting is 20 μm to 50 μm, and the diameter of the second concavo-convex structure formed under chemical blasting is 2 μm to 5 μm.

Further, as shown in fig. 4, since the second concave-convex structure is smaller than the first concave-convex structure, the first concave-convex structure 403 with higher density is gathered at the middle part 401 and the connected edge part 402 (such as the edge upper part 4021) of the shell 400 after the physical blasting treatment, and therefore, the influence of the second concave-convex structure 404 is smaller after the middle part 401 of the shell 400 is subjected to the chemical blasting treatment, and the user feels that the first concave-convex structure 403 is still present.

In contrast, in the edge portion 402 (for example, the edge lower portion 4022) to which no physical blasting is applied, the effect of the light surface is large, and the user feels the second uneven structure 404 and can see a fine granular feeling.

After the physical blasting treatment and the chemical blasting treatment, a first glossiness of the middle part and the connected edge part of the shell belongs to a first glossiness range, and the value of the first glossiness is gradually reduced from the middle part to the edge part of the shell.

The second gloss level of the remaining edge portion of the case belongs to a second gloss range, and the value of the first gloss range is greater than the value of the second gloss range.

Second embodiment

Referring to fig. 5, a flow chart of another method for processing a surface of a housing according to an embodiment of the present invention is shown, which may specifically include the following steps:

step 501, performing physical sand blasting on the outer surface of the shell.

In the embodiment of the invention, the middle part of the shell is a plane, and the edge part extends from the edge of the middle part to form a circular arc.

Step 502, performing a first cleaning process on the housing.

In a specific implementation, the first cleaning treatment comprises oil removal treatment and water washing treatment.

The degreasing treatment is to soak the shell in a degreasing agent to remove oil stains formed on the surface of the shell during physical blasting or during a previous process.

Wherein the main component of the oil removing agent is sodium carbonate (Na)₂CO₃) After sodium carbonate is dissolved in water, hydrolysis reaction is carried out, and the generated sodium hydroxide (NaOH) and grease are subjected to saponification reaction to remove oil stains.

The water washing treatment is to soak the shell in water to remove dirt and residual solution on the surface of the shell.

Step 503, soaking the housing in a second etching solution to perform a first chemical polishing process.

The first chemical polishing process is a preliminary chemical polishing process, and the shell is soaked in a second etching solution to mask the defects of the polished surface (i.e., the dirt on the surface of the shell) and make the whole surface uniform.

In one example of an embodiment of the present invention, the second etching solution is sulfuric acid (H)₂SO₄) And phosphoric acid (H)₃PO₄) The mixed solution of (1), wherein sulfuric acid (H)₂SO₄) Can accelerate corrosion, phosphoric acid (H)₃PO₄) Can increase luster, sulfuric acid (H)₂SO₄) And phosphoric acid (H)₃PO₄) The ratio of the first chemical polishing time to the second chemical polishing time is 5:1-7:1, the temperature of the first chemical polishing is 80-90 ℃, and the time of the first chemical polishing is 20-60 s.

And 504, performing chemical sand blasting treatment on the outer surface of the shell by using a first etching solution.

And 505, soaking the shell in a third corrosion solution to perform a second chemical polishing treatment.

And the second chemical polishing is the second chemical polishing, and the shell is soaked in a third corrosive solution to increase the fine gloss of the surface.

In one example of an embodiment of the present invention, sulfuric acid (H)₂SO₄) And phosphoric acid (H)₃PO₄) Sulfuric acid (H)₂SO₄) And phosphoric acid (H)₃PO₄) In a ratio of 6:1, wherein sulfuric acid (H)₂SO₄) Can accelerate corrosion, phosphoric acid (H)₃PO₄) Can increase luster, sulfuric acid (H)₂SO₄) And phosphoric acid (H)₃PO₄) In a ratio of 5:1 to 7:1, the temperature of the first chemical polishing is 80 ℃ to 90 ℃, and the first chemical polishing is carried outThe time of (a) is 20-60 s.

Step 506, performing a second cleaning process on the shell.

In a specific implementation, the second cleaning treatment comprises water washing treatment and ash removal treatment.

The ash removal treatment is to soak the shell in an acid solution to remove impurities such as iron (Fe), silicon (Si) and the like on the surface of the shell.

Wherein the acidic solution is nitric acid (HNO)₃) The concentration is 5-8%, and the ash removal time is 5-8 s.

And 507, carrying out anodic oxidation treatment on the outer surface of the shell to generate an oxide film.

In specific implementation, the shell is soaked in the oxidizing liquid, and current is applied to generate an oxide film, so that the corrosion of the shell can be prevented, the wear resistance can be improved, and the like.

Wherein the oxidizing solution is sulfuric acid (H)₂SO₄) And aluminum sulfate (Al)₂(SO₄)₃) The oxidation time is 20s-38s, the temperature is 18-20 ℃, the voltage is 12V-15V, and the thickness of the oxide film is about 11 mu m.

And step 508, performing third cleaning treatment on the shell.

In a specific implementation, the third cleaning treatment comprises a water washing treatment.

In step 509, the outer surface of the case is dyed, and the oxide film is colored.

For most shells requiring surface finishing, an oxide film with high transparency can be obtained by performing anodic oxidation after chemical polishing.

The oxide film can adsorb a wide variety of organic dyes and inorganic dyes, thereby having various vivid colors. The color film is an anti-corrosion layer and a decorative layer.

In the embodiment of the present invention, the dyeing process is to soak the shell in an organic dye to color the oxide film.

Wherein, the organic dye comprises acid dye (such as C.I. acid Orange 20), metal salt type acid dye (such as C.I. acid Violet 58), acid mordant dye (such as C.I. mordant Red 3), etc., the dyeing time is 1min-5min, and the temperature is normal temperature.

Step 510, performing a fourth cleaning process on the shell.

In a specific implementation, the fourth cleaning treatment comprises a water washing treatment.

And 511, sealing the outer surface of the shell to seal the pores in the oxide film.

In order to improve the quality of the shell and ensure firm dyeing, the micro pores of the oxide film layer are sealed after dyeing, and the surface of the shell becomes uniform and nonporous after sealing treatment to form a compact oxide film.

The dye is deposited in the oxidation film and cannot be wiped off, and the oxidation film after being sealed has no adsorbability any more, so that the pollution or early corrosion caused by the adsorption of harmful substances can be avoided, and the performances of pollution prevention, corrosion resistance and the like of the anodic oxidation film are improved.

In the embodiment of the invention, the shell can be soaked in the hole sealing liquid for hole sealing treatment.

Wherein the hole sealing liquid is nickel acetate (C)₄H₆NiO₄) The solution, the hole sealing temperature is 95-98 ℃, and the hole sealing time is 5-10 min.

And step 512, performing fifth cleaning treatment on the shell.

In a specific implementation, the fifth cleaning treatment includes a water washing treatment and a drying treatment.

The drying treatment is to place the shell at a higher temperature to dry the liquid on the surface, mainly water.

Wherein the drying temperature is 75-85 ℃, and the drying time is 8-15 min.

Third embodiment

Referring to fig. 6, a schematic structural diagram of a housing according to an embodiment of the present invention is shown.

As shown in fig. 6, the outer surface of the casing 600 includes a middle portion 601 and a rim portion 602, the middle portion 601 is a plane, and the rim portion 602 extends inward from the edge of the middle portion 601 and forms an arc shape; wherein rim portion 602 comprises a rim upper portion 6021 and a rim lower portion 6022, rim upper portion 6021 being connected to middle portion 601;

the middle portion 601 and rim upper portion 6021 of the outer surface of the case 600 have a first relief structure 603;

the outer surface of the housing 600 has a second relief structure 604;

the density of the first concave-convex structure 603 decreases gradually from the middle 601 of the casing 600 to the edge 602, and the density of the second concave-convex structure 604 is greater than the density of the first concave-convex structure 603 in the middle of the outer surface of the casing 600.

Preferably, the first glossiness of the middle portion 601 and the rim upper portion 6021 of the outer surface of the case 600 belongs to the first glossiness range, and the first glossiness gradually decreases from the middle portion 601 of the case 600 toward the rim part 602;

the second gloss level of the rim lower portion 6022 belongs to the second gloss range, and the value of the first gloss range is larger than that of the second gloss range.

In this way, in the embodiment of the present invention, the middle part and the upper part of the edge of the outer surface of the shell have the first concave-convex structure, the outer surface of the shell has the second concave-convex structure, the distribution density of the first concave-convex structure is gradually reduced from the middle part of the shell to the edge part, the distribution density of the second concave-convex structure is greater than the distribution density of the first concave-convex structure in the middle part of the outer surface of the shell, the sand blasting texture of the shell is gradually reduced from coarse to fine, and the sand blasting texture changes along with the change of the radian of the edge of the shell.

Further, a first glossiness of the middle portion of the outer surface of the shell and the upper portion of the edge belongs to a first glossiness range, a second glossiness of the lower portion of the edge belongs to a second glossiness range, a value of the first glossiness range is larger than a value of the second glossiness range, the glossiness of the shell changes from dull to bright gradually, the glossiness changes along with radian changes of the edge of the shell, and the gradual change effect is excessively natural.

Fourth embodiment

Fig. 7 is a schematic structural diagram of a mobile terminal according to another embodiment of the present invention. Specifically, the mobile terminal 700 in fig. 7 may be a mobile phone, a tablet computer, a Personal Digital Assistant (PDA), or a vehicle-mounted computer.

The mobile terminal 700 in fig. 7 includes a Radio Frequency (RF) circuit 710, a memory 720, an input unit 730, a display unit 740, a housing 750, a processor 760, an audio circuit 770, a wifi (wireless fidelity) module 780, and a power supply 790.

The input unit 730 may be used, among other things, to receive numeric or character information input by a user and to generate signal inputs related to user settings and function control of the mobile terminal 700. Specifically, in the embodiment of the present invention, the input unit 730 may include a touch panel 731. The touch panel 731, also referred to as a touch screen, can collect touch operations of a user (e.g. operations of the user on the touch panel 731 by using a finger, a stylus pen, or any other suitable object or accessory) thereon or nearby, and drive the corresponding connection device according to a preset program. Alternatively, the touch panel 731 may include two portions of a touch detection device and a touch controller. The touch detection device detects the touch direction of a user, detects a signal brought by touch operation and transmits the signal to the touch controller; the touch controller receives touch information from the touch sensing device, converts the touch information into touch point coordinates, sends the touch point coordinates to the processor 760, and can receive and execute commands sent from the processor 760. In addition, the touch panel 731 may be implemented by various types, such as a resistive type, a capacitive type, an infrared ray, and a surface acoustic wave. In addition to the touch panel 731, the input unit 730 may include other input devices 732, and the other input devices 732 may include, but are not limited to, one or more of a physical keyboard, function keys (such as volume control keys, switch keys, etc.), a trackball, a mouse, a joystick, and the like.

The display unit 740 may include a display panel 741, and optionally, the display panel 741 may be configured in the form of L CD or Organic light emitting diode (Organic L light-emitting diode, O L ED).

It should be noted that the touch panel 731 can cover the display panel 741 to form a touch display screen, and when the touch display screen detects a touch operation on or near the touch display screen, the touch display screen is transmitted to the processor 760 to determine the type of the touch event, and then the processor 760 provides a corresponding visual output on the touch display screen according to the type of the touch event.

The touch display screen comprises an application program interface display area and a common control display area. The arrangement modes of the application program interface display area and the common control display area are not limited, and can be an arrangement mode which can distinguish two display areas, such as vertical arrangement, left-right arrangement and the like. The application interface display area may be used to display an interface of an application. Each interface may contain at least one interface element such as an icon and/or widget desktop control for an application. The application interface display area may also be an empty interface that does not contain any content. The common control display area is used for displaying controls with high utilization rate, such as application icons like setting buttons, interface numbers, scroll bars, phone book icons and the like.

The processor 760 is a control center of the mobile terminal 700, connects various parts of the entire handset using various interfaces and lines, and performs various functions of the mobile terminal 700 and processes data by operating or executing software programs and/or modules stored in the first memory 721 and calling data stored in the second memory 722, thereby integrally monitoring the mobile terminal 700. Alternatively, processor 760 may include one or more processing units.

In the embodiment of the present invention, the outer surface of the casing 750 includes a middle portion and an edge portion, the middle portion is a plane, and the edge portion extends inward from an edge of the middle portion and forms an arc shape; the edge part comprises an upper edge part and a lower edge part, and the upper edge part is connected with the middle part;

the middle part of the outer surface of the shell 750 and the upper part of the edge are provided with a first concave-convex structure;

the outer surface of the housing 750 has a second concave-convex structure;

the distribution density of the first concave-convex structure is gradually reduced from the middle of the shell 750 to the edge, and the distribution density of the second concave-convex structure is greater than that of the first concave-convex structure in the middle of the outer surface of the shell 750.

Optionally, a first gloss level of the middle portion of the outer surface of the case 750 and the upper portion of the rim falls within a first gloss range, the first gloss level gradually decreasing from the middle portion of the case to the rim portion;

the second gloss level of the lower portion of the rim belongs to a second gloss range, the value of the first gloss range being greater than the value of the second gloss range.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A method of finishing a surface of a case, wherein an outer surface of the case includes a middle portion and a rim portion, the middle portion being a flat surface, the rim portion extending inward from an edge of the middle portion and forming an arc shape, the rim portion including a rim upper portion and a rim lower portion, the rim upper portion being connected to the middle portion, the method comprising:

carrying out physical sand blasting treatment on the outer surface of the shell, wherein a first concave-convex structure is formed in the middle of the outer surface of the shell and on the upper part of the edge of the outer surface of the shell; the distribution density of the first concave-convex structure is gradually reduced from the middle part of the shell to the edge part;

carrying out chemical sand blasting treatment on the outer surface of the shell by using a first corrosion solution so as to enable the outer surface of the shell to have a second concave-convex structure; the second concave-convex structure is smaller than the first concave-convex structure, and the distribution density of the second concave-convex structure is greater than that of the first concave-convex structure in the middle of the outer surface of the shell;

a first glossiness of the middle part of the outer surface of the shell and the upper part of the edge belongs to a first glossiness range, and the first glossiness is gradually reduced from the middle part of the shell to the edge part;

2. The method of claim 1, wherein the step of physically blasting the exterior surface of the shell comprises:

a spray gun is arranged above the middle part of the outer surface of the shell;

the spray gun sprays abrasive to the outer surface of the shell.

3. The method of claim 2, wherein the step of chemically blasting the exterior surface of the shell with the first etching solution comprises:

soaking the shell in the first etching solution;

the outer surface of the shell forms a second concave-convex structure.

4. The method of claim 1, wherein prior to the step of chemically blasting the exterior surface of the shell with the first etching solution, the method further comprises:

and soaking the shell in a second corrosion solution to carry out first chemical polishing treatment.

5. The method of claim 1, wherein after the step of chemically blasting the exterior surface of the shell with the first etching solution, the method comprises:

and soaking the shell in a third corrosion solution to perform a second chemical polishing treatment.

6. The method of claim 1 or 2 or 3 or 4 or 5, wherein after the step of chemically blasting the exterior surface of the shell with the first etching solution, the method further comprises:

carrying out anodic oxidation treatment on the outer surface of the shell and generating an oxide film;

dyeing the outer surface of the shell, wherein the oxide film is colored;

and sealing the outer surface of the shell to seal the pores in the oxide film.

7. The method of claim 6,

prior to the step of chemically blasting the exterior surface of the housing with the first etching solution, the method further comprises:

carrying out first cleaning treatment on the shell;

wherein the first cleaning treatment comprises oil removal treatment and water washing treatment;

before the step of anodizing the outer surface of the case and generating an oxide film, the method includes:

carrying out secondary cleaning treatment on the shell;

wherein the second cleaning treatment comprises water washing treatment and ash removal treatment;

prior to the step of dyeing the outer surface of the shell, the method comprises:

carrying out third cleaning treatment on the shell;

wherein the third cleaning treatment comprises water washing treatment;

before the step of sealing the outer surface of the casing, the method includes:

cleaning the outer surface of the shell for the fourth time;

wherein the fourth cleaning treatment comprises water washing treatment;

after the step of sealing the outer surface of the casing, the method includes:

performing fifth cleaning treatment on the shell;

and the fifth cleaning treatment comprises water washing treatment and drying treatment.

8. The method according to claim 1, 2, 3, 4 or 5, wherein the grit of the physical blasting is 170-205 zircon sand, and the pressure of the physical blasting is 0.6KG/cm²-1.6KG/cm²And the physical sand blasting time is 30-60 s.

9. The method according to claim 1, 2, 3, 4 or 5, characterized in that the first etching solution is a mixed solution of sodium nitrate and sodium hydroxide, the volume ratio of the sodium nitrate to the sodium hydroxide is 4:1-6:1, the temperature of the chemical blasting is 70-85 ℃, and the time of the chemical blasting is 30-50 s.

10. A shell is characterized in that the outer surface of the shell comprises a middle part and an edge part, wherein the middle part is a plane, and the edge part extends inwards from the edge of the middle part and forms an arc shape; the edge part comprises an upper edge part and a lower edge part, and the upper edge part is connected with the middle part;

the distribution density of the first concave-convex structure is gradually reduced from the middle part of the shell to the edge part, and the distribution density of the second concave-convex structure is greater than that of the first concave-convex structure in the middle part of the outer surface of the shell;

11. A mobile terminal characterized by comprising a housing according to claim 10.