CN112867301A

CN112867301A - Shell assembly, preparation method and electronic equipment

Info

Publication number: CN112867301A
Application number: CN201911100411.7A
Authority: CN
Inventors: 李�杰
Original assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Current assignee: Guangdong Oppo Mobile Telecommunications Corp Ltd
Priority date: 2019-11-12
Filing date: 2019-11-12
Publication date: 2021-05-28
Anticipated expiration: 2039-11-12
Also published as: CN112867301B

Abstract

The application provides a shell assembly, a preparation method and an electronic device. The method comprises the following steps: preparing a housing base body, wherein the housing base body is formed by a transparent material and comprises a bottom surface and 4 side walls surrounding the bottom surface; forming a boundary line ink layer on the surface of the bottom surface of the shell substrate facing one side of the accommodating space, wherein the boundary line ink layer is positioned at the boundary between the bottom surface and the side wall; attaching an appearance membrane on the bottom surface, and enabling the boundary of the appearance membrane to coincide with the edge of one side, facing the bottom surface, of the boundary line ink layer; and carrying out ink spraying treatment on the shell substrate attached with the appearance membrane to form an ink layer. Therefore, the shell assembly formed by the method can form a good consistent appearance effect on the bottom surface and the side wall of the inner side of the shell assembly.

Description

Shell assembly, preparation method and electronic equipment

Technical Field

The application relates to the technical field of electronics, in particular to a shell assembly, a preparation method and electronic equipment.

Background

With the continuous progress of electronic technology and the improvement of aesthetic level of people, in order to achieve better holding feeling and visual integrity, the appearance shell of the electronic equipment is also changed in form: more and more electronic devices have abandoned the traditional screen, middle frame and back cover designs, and have instead adopted a body with a single-piece middle frame and back cover. In addition, materials such as optical plastics and glass are gradually replacing metal materials, and are increasingly applied to electronic device housings. However, most of materials such as plastic and glass are transparent and have no color, so that an appearance film layer needs to be additionally arranged on a glass or plastic casing substrate. However, due to the special structure of the integrated housing of the middle frame and the rear cover, even if the housing base body formed of plastic or the like can be integrated, it is difficult to obtain a good appearance effect with good appearance consistency at the side wall and the bottom surface of the integrated housing. In particular, at the corner between the side wall and the bottom surface of the case, defects such as bubbling and wrinkles of the structure such as the appearance film layer are likely to occur.

Therefore, the current housing assembly, particularly the housing assembly with the integrated middle frame and rear cover, the manufacturing method and the electronic device still need to be improved.

Disclosure of Invention

The present application is directed to solving, at least to some extent, one of the technical problems in the related art. Therefore, an object of the present invention is to provide a method for manufacturing a housing assembly, in which the housing assembly obtained by the method is a shell with a back shell and a middle frame integrated together, and the bottom surface of the shell and the side wall serving as the middle frame can have uniform appearance effect, and the method has good product yield, and the R-corner of the housing is not prone to have the undesirable phenomena of bubbles, wrinkles, etc.

In one aspect of the present application, there is provided a method of making a housing assembly, comprising: preparing a housing base body which is formed by a transparent material and comprises a bottom surface and 4 side walls surrounding the bottom surface, wherein the bottom surface and the side walls define a containing space on the inner side of the housing base body; forming a boundary line ink layer on the surface of the bottom surface of the shell substrate facing one side of the accommodating space, wherein the boundary line ink layer is positioned at the boundary between the bottom surface and the side wall; attaching an appearance membrane on the bottom surface, and enabling the boundary of the appearance membrane to coincide with the edge of one side, facing the bottom surface, of the boundary line ink layer; and carrying out ink spraying treatment on the shell substrate attached with the appearance membrane so as to form an ink layer on one side of the side wall facing the accommodating space, the surface of the boundary ink layer and the surface of the appearance membrane far away from the shell substrate. The shell assembly formed by the method can form a good-consistency appearance effect on the bottom surface and the side wall of the inner side of the shell assembly.

In another aspect of the present application, a housing assembly is presented. The housing assembly is prepared by the method described above. Thus, the housing assembly has all the features and advantages of the housing prepared by the method described above, and thus, the description thereof is omitted. Generally, the shell assembly can realize the integration of the rear shell and the middle frame, and has better appearance consistency at the rear shell and the middle frame.

In another aspect of the present application, the present application provides a housing assembly, comprising: the shell body is provided with a bottom surface and 4 side walls surrounding the bottom surface, and an accommodating space is defined between each side wall and the bottom surface; an appearance membrane disposed on a surface of the bottom surface on a side facing the accommodation space; the boundary line ink layer is positioned on the surface of the bottom surface, which is arranged on one side of the appearance membrane, and is positioned at the boundary position between the bottom surface and the side wall, and the edge of the boundary line ink layer, which faces one side of the bottom surface, is superposed with the edge of the appearance membrane; and the ink layer covers the surface of one side of the side wall facing the accommodating space, and the surface of one side of the appearance membrane and the boundary line ink layer away from the shell substrate. Therefore, the shell can realize the integration of the rear shell and the middle frame, and the rear shell and the middle frame can have better appearance consistency. The shell is simple in structure, convenient to prepare, and capable of achieving good product yield and further achieving low production cost.

Drawings

FIG. 1 shows a schematic flow diagram of a method of preparing a housing assembly according to one example of the present application;

FIG. 2 shows a partial schematic flow diagram of a method of preparing a housing assembly according to one example of the present application;

FIG. 3 shows a schematic flow diagram of a method of preparing a housing assembly according to one example of the present application;

FIG. 4 shows a schematic structural view of a housing base according to an example of the present application;

FIG. 5 shows a schematic cross-sectional view of the housing base in the direction B-B' of FIG. 4 according to an example of the present application;

FIG. 6 shows a schematic cross-sectional view of the housing base in the direction A-A' of FIG. 4 according to an example of the present application;

FIG. 7 shows a schematic flow diagram of a method of preparing a housing assembly according to one example of the present application;

fig. 8 shows a schematic structural diagram of an electronic device according to an example of the application.

Detailed Description

Embodiments of the present application are described in detail below. The following description of the embodiments is merely exemplary in nature and is in no way intended to limit the present disclosure. The examples, where specific techniques or conditions are not indicated, are to be construed according to the techniques or conditions described in the literature in the art or according to the product specifications.

In one aspect of the present application, a method of making a housing assembly is provided. Generally speaking, the shell assembly obtained by the method is a shell with the integration of the rear shell and the middle frame, the bottom surface of the shell and the side wall serving as the middle frame can have consistent appearance effect, the method has better product yield, and the poor phenomena of bubbles, folds and the like are not easy to occur at the R corner of the shell.

For convenience of understanding, the following first briefly explains the principle that the method can achieve the above beneficial effects:

as mentioned above, the transparent casing substrate made of glass or plastic material needs to additionally form an appearance film layer on the casing substrate. The preparation process of the prior appearance film layer can be roughly divided into three types: firstly, an appearance layer is directly prepared on a shell substrate, for example, a film layer structure with certain texture effect, metallic luster or specific color is formed by utilizing an optical coating process, a spraying process and the like. And secondly, the prepared appearance membrane is formed on the shell through mounting. Alternatively, it may be realized using an IMT decoration process (in-mold mounting process). When the three processes are applied to the preparation of the appearance layer on the shell with the side wall and the bottom surface of the shell with larger included angles, particularly 4 side walls with larger included angles, the production yield is generally low, and defects such as flow marks, impurities, bubbles or folds (particularly the R-angle of the shell) are easy to occur. The inventor finds that this is mainly due to the fact that in the case where the middle frame and the rear shell are integrated, the included angle between the bottom surface and the side wall of the case base body is large, and particularly, the stress is large at the corner between the bottom surface and the two adjacent side walls, i.e., the R corner (for example, as shown by the dashed line box in fig. 4). For example, a process such as optical coating directly performed on the surface of the case base often requires first hardening the case. In the step, when the bending angle between the bottom surface and the side wall is large, defects such as flow marks, impurities, bubbles and the like are easily generated in the hardening treatment step, so that the overall yield of the process is low. In the mounting process, the appearance membrane is well prepared, so that the deformation of the membrane in the mounting process is limited, and poor wrinkles are easily generated at the R corner and the like of a product. Similarly, the mounting yield rate of the IMT decoration process is also greatly reduced when the bending angle between the rear cover and the side wall is large, and the IMT process also easily causes that a separation line is formed at the joint of the rear cover plate and the middle frame, which affects the overall appearance of the housing.

According to the method, firstly, a boundary line ink layer is formed at the junction between the bottom surface and the side wall, and then the prepared appearance membrane is attached to the bottom surface of the relatively flat shell with a large area in a mode similar to a mounting process. And then, an ink layer which covers the whole inner surfaces of the side walls and the bottom surface is formed in a mode of spraying ink and solidifying. Therefore, a better appearance effect can be obtained in most areas (namely the bottom surface) of the shell by depending on the appearance membrane, on one hand, the boundary line ink layer can relieve the difference in appearance between the side wall and the bottom surface to form buffer, on the other hand, the boundary line ink layer can cover a part of areas with larger bending angles between the side wall and the bottom surface, and the boundary line ink layer only covers the boundary between the bottom surface and the side wall, so that the boundary line ink layer does not have larger bending, and the defects caused by larger stress and the like can be relieved. And the finally formed ink layer covers all areas of the side wall and the bottom surface, so that the visual effect that the appearances of the side wall and the bottom surface are consistent can be obtained by controlling the color of the ink layer. In addition, since the portions of the bottom surface and the side wall having a large bending angle are already covered with the boundary ink layer, the thickness of the case is increased, and the ink layer is less likely to have defects such as wrinkles at this position. On the other hand, even if the ink layer has a poor appearance, since the boundary ink layer is in direct contact with the case base, the influence of the wrinkles of the ink layer on the overall appearance of the case can be reduced.

The bending angle is an included angle between a plane where the bottom surface is located and a tangent of the side wall. For example, as shown in fig. 5, and a greater is indicative of a greater curvature of the sidewall, wherein in some embodiments of the present application, the bending angle α may be greater than 70 degrees, and may be locally, for example, 90 degrees at the R angle shown by the dashed box in fig. 4. From this, sufficient accommodation space can be injectd between the lateral wall of this casing subassembly and the bottom surface for accomodate structures such as electronic equipment's display screen, mainboard, battery, and then realize the integration of back lid and center.

The individual steps of the above-described method are described in detail below with reference to specific examples of the present application. Referring to fig. 1, the method may specifically include:

s100: preparing a housing base body formed of a transparent material

According to some examples of the present application, the housing base may be pre-prepared or may be formed by processes including, but not limited to, injection molding, hot pressing, hot bending, and the like. Specifically, for example, a case base including a bottom surface and 4 side walls surrounding the bottom surface, which define a housing space on the inner side of the case base, may be obtained by processing a transparent material such as plastic, glass, or the like in this step. The housing base formed in this step may have a configuration as shown in fig. 4-6, i.e., housing base 100 may have a bottom surface 110, and four sidewalls (120A-120D as shown).

According to the examples of the present application, the material of the housing base is not particularly limited, and may be, for example, glass, or an optical-grade transparent plastic material. Specifically, at least one of optical-grade polymethyl methacrylate and optical-grade polycarbonate may be included. Specifically, referring to fig. 3, the method may include:

s110: carrying out injection molding treatment on the transparent plastic to obtain a rough blank of the shell substrate

According to an example of the application, the housing base blank is obtained in this step by injection moulding. The injection molding processing equipment can be a 120-ton high-pressure injection molding machine. The transparent plastic can be heated to be molten and injected into an injection mold to form a shell matrix at the injection pressure of 100-150MPa, the injection time is 2-4s, and pressure-maintaining molding is carried out at the pressure of 40-50MPa, and the pressure-maintaining molding time is 30-40 s. More specifically, the melting temperature of the material can be 240 ± 10 ℃, and the injection pressure of the injection filling is 120-. Therefore, the shell substrate which has good product flatness, uniform thickness and no internal stress, rainbow patterns and other defects can be obtained.

S120: the rough blank of the shell substrate is subjected to fine finishing treatment

According to the example of the present application, in order to further improve the effect of preparing the housing base body, an operation of finishing treatment may be further included after the injection molding is performed. Specifically, the rough blank of the housing base body subjected to the injection molding treatment can be subjected to finishing treatment to obtain the housing base body with the contour and the size more meeting the preset requirements. Specifically, the finishing process may be a cutting process including, but not limited to, using a numerical control machine tool, and the machining precision of the finishing process may be ± 8 μm. Namely: the difference between the actual cutting position and the predetermined cutting position may be ± 8 μm. For example, the finishing process may be performed using a CNC computer numerically controlled machine tool, such as a five-axis CNC engraving machine. The finishing process may also include a process of drilling a hole finish and cutting an edge vent on the injection molded housing base. For example, according to some examples of the present application, the spindle speed of the numerically controlled machine tool process may be 45000-. The fine trimming treatment under the condition can improve the product yield and ensure the processing efficiency.

S200: forming a boundary line ink layer on the surface of the bottom surface of the shell substrate facing the accommodating space

According to an example of the present application, the boundary ink layer may be formed on a surface of the bottom surface on a side facing the accommodating space in this step. The boundary line printing ink layer can limit the edge of the appearance membrane which is subsequently attached, and can be used for shielding and decorating the boundary line which is generated by the appearance membrane which is subsequently attached and the ink which is sprayed, so that the difference between the appearance membrane and the subsequently formed printing ink layer is relieved, and the overall appearance consistency of the shell is improved. The specific color of the boundary ink layer is not particularly limited, and may be any of black, white, red, and the like, or may be a color that matches an appearance film to be subsequently attached.

Referring to (a) and (b) of fig. 7, after obtaining the housing substrate 100, a circle of boundary ink layer 200 may be first formed at the boundary position between the bottom surface 110 and the sidewall 120. The boundary of the boundary layer ink layer 200 near the side of the sidewall 120 may cover a part of the inner surface of the sidewall 120 (i.e., the surface facing the side of the accommodating space), and the boundary of the boundary layer ink layer 200 near the bottom surface 110 may cover a part of the inner surface of the bottom surface 110 (i.e., the surface facing the side of the accommodating space). That is, the boundary ink layer 200 may extend a short distance to the bottom side and the sidewall side at the boundary of the bottom 110 and the sidewall 120, respectively. Thus, the boundary ink layer 200 can cover the portion of the inner surface of the case base where the bending angle is largest. Since the boundary ink layer 200 is only a ring of annular ink layer with a smaller width, although the boundary ink layer 200 is located at a position with a larger bending angle, compared with the related art that a whole layer structure is used to cover the bottom surface and the sidewall at the same time, the arrangement method can also alleviate or even avoid the defects of wrinkles, faults and the like caused by the stress problem of the boundary ink layer 200.

Specifically, the boundary line ink layer 200 may be formed by pad printing using a soft head at the boundary of the side walls on the bottom surface, and the forming of the boundary line ink layer may include performing the pad printing a plurality of times, and the thickness of the ink formed by each pad printing may be 5 to 14 μm. The width of the boundary ink layer can be 0.6-1 mm. Accordingly, on the one hand, the boundary region between the bottom surface and the side wall can be sufficiently covered, and on the other hand, the production yield of the formed boundary ink layer 200 can be ensured, and defects such as dropping and ink wrinkles due to an excessively large width or thickness of the boundary ink layer 200 do not occur.

According to some specific examples of the present application, after the pad printing, the pad printing ink may be further subjected to a curing process, wherein the curing process is performed at a temperature of 65-85 ℃ for 20-45 minutes. The boundary ink layer 200 can be obtained by repeating the operations of pad printing ink and curing treatment twice.

Specifically, the shell body obtained in the foregoing can be placed on a pad printing tool, and a circle of ink lines can be pad printed on the junction of the bottom of the inner concave surface and the side wall of the shell body, wherein the inner concave surface faces upwards (the accommodating space faces upwards for preventing the ink lines from flowing upwards). The pad printing adopts a rubber head, the precision of a pad printing steel plate is 100 lines, the pad printing is carried out twice, and the thickness of each layer of printing ink is 10 +/-2 mu m. And (5) curing and baking the product subjected to pad printing for 30min at the temperature of 80 ℃. Thus, a boundary ink layer can be obtained.

S300: attaching an appearance film to the bottom surface

According to an example of the application, in the step, the appearance membrane is attached to the bottom surface, and the boundary of the appearance membrane is overlapped with the edge of the boundary line ink layer facing to the bottom surface.

For example, the housing base with the previously obtained transfer-printed boundary ink layer can be attached to the appearance film such that the edge of the appearance film is positioned on the previously obtained transfer-printed boundary ink layer. Specifically, a vacuum laminating machine can be adopted for laminating, and the deformation of the silica gel in the jig is 1.8-2.2mm during laminating. The appearance membrane can be heated in the attaching process, the temperature can be 25-40 ℃, and the attaching time is 20-40 s. In order to ensure that the bonded product has no bad appearance such as bubble wrinkle, the bonding process can be further performed with a defoaming treatment, the defoaming pressure of the defoaming treatment can be 4-6.5kgf, for example 6kgf, the defoaming temperature can be 45-55 ℃, for example 50 ℃, and the defoaming time can be 15-25min, for example 20 min.

The appearance film attached in the step can be a film with certain texture, metal luster or color. For example, the appearance film may include a transparent film substrate, and at least one layer having an appearance effect formed thereon. The appearance film may be pre-prepared. Alternatively, referring to fig. 2, it may also be obtained by at least one of the following steps:

s10: UV transfer printing on transparent film substrate to form optical texture layer

According to an example of the present application, a UV transfer is first performed on the transparent film substrate in this step to form an optical texture layer. In particular, the transparent film substrate may be composed of a transparent polymer, such as may be formed from materials including, but not limited to, PET, TPU, and the like.

The optical texture layer may be formed by an ultraviolet light curing adhesive, for example, an adhesive layer having a certain concave-convex texture structure may be formed on the transparent film substrate by a transfer printing technique, wherein the concave-convex structure is disposed at a side away from the transparent substrate. The ultraviolet light curing glue can comprise polyurethane acrylate, and the thickness of the ultraviolet light curing glue can be 7-9 μm, such as 7.5 μm, 8 μm, 8.5 μm and the like. Therefore, the operation and the curing are convenient, the cured texture layer has enough thickness to show the appearance of the texture, and the combination with the transparent film substrate can be firmer. According to some examples of the present application, the uv irradiation energy for curing the uv curable adhesive may be 1000 and 1200MJ, for example, 1050, 1100, 1150MJ, etc. Specifically, a UV transfer printing machine can be used for uniformly coating a layer of curing glue on the PET membrane, and the curing glue is cured after being irradiated by ultraviolet light to form the optical texture of the micro-nano structure.

S20: forming an optical coating film on a transparent film substrate

According to an example of the present application, an optical coating layer is formed on a transparent film substrate in this step. The optical coating layer can be a film layer with certain transmittance and metal luster, and can provide metal-like texture for the appearance film. Specifically, the optical coating layer may be formed by evaporation or sputtering. The optical coating (OPVD) may be a brightness enhancing film.

Specifically, the optical coating layer may be a single-layer metal film formed of In or an alloy of In and Sn, for example, and may have a thickness of 20 to 30nm, or the optical coating layer may include a plurality of sequentially laminated sub-layers, and the total thickness of the optical coating layer may be 100-500nm, for example, specifically, may include a plurality of sequentially laminated TiO layers₂Sublayer and SiO₂Sub-layer, or a plurality of successively stacked Nb₂O₅Sublayer and SiO₂And (3) sub-layers. The optical coating layer with the structure can provide a good metal luster effect and has a certain increment reflection increasing effect. And the thickness of the coating layer is moderate, so that the defects of falling, peeling or cracks and the like are not easy to occur.

S30: forming a bottom ink layer by silk screen printing

According to an embodiment of the present invention, in the step, a hiding ink layer is formed by screen printing on the transparent film substrate on which at least one of the optical texture layer and the optical coating layer is formed. The bottom-covering ink layer can be formed on the surface of the optical texture layer or the optical coating layer on the side far away from the transparent film substrate. Because the sublayer structures formed in the front have certain permeability, the covering bottom ink layer is formed maliciously, the integral transmittance of the appearance membrane is reduced, and the appearance effect of the appearance membrane is improved.

In particular, the under-ink layer may comprise a plurality of ink sub-layers, each ink sub-layer having a thickness of 6-8 μm. Specifically, the screen printing ink may be two layers of white ink, one layer of gray ink, or three layers of black ink.

The step of forming the cover and bottom ink layers by silk-screen printing can further comprise the step of baking the transparent film substrate printed with the cover and bottom ink at the temperature of 65-90 ℃ for 20-45 min. Specifically, for example, the baking temperature may be 80 ℃ for 30 min.

As can be understood by those skilled in the art, the laminated structure included in the appearance membrane is designed according to the appearance requirement of the appearance membrane. For example, in some examples of the present application, the appearance film may further include a color layer, and the color layer may be formed of ink having a specific color. The appearance membrane can contain any one, two, three or all of the texture layer, the optical coating layer, the color layer and the bottom covering ink layer.

S40: laser cutting the transparent film substrate

According to an example of the present application, the transparent film base material is laser-cut in this step to obtain an appearance film having a shape matching the bottom surface. Therefore, the formed appearance membrane can be correspondingly attached to the bottom surface of the shell base body in the subsequent step.

The cutting drawing with the drawing drawn can be guided into a laser cutting machine, and laser cutting is carried out on a single large decorative membrane. Utilize the vacuum to breathe in the cutting process and make the diaphragm place levelly and smoothly, adjust cutting energy to suitable level, guarantee to cut out that diaphragm surface printing ink does not have the condition of scorching, and the diaphragm edge is neat without the sawtooth. Specifically, the size of the cut appearance film sheet may be determined according to the size defined by the boundary ink formed previously.

In order to reduce the requirement on alignment precision in the subsequent attaching step, the size of the cut appearance membrane can be enlarged by 0.2mm relative to the inner frame of the boundary line ink layer. That is, when the transparent film substrate is subjected to laser cutting, the side length of the formed appearance film is 0.25-0.15mm larger than that of the bottom surface. Thus, the area of the appearance membrane is slightly larger than the area of the area defined by the border ink layer. Therefore, even if a small amount of deviation occurs in alignment, the whole area defined by the boundary line ink layer can be covered by the appearance membrane, the condition that part of the bottom surface is not covered by the appearance membrane or the boundary line ink layer due to the deviation in alignment cannot occur, and the defect that the obtained shell assembly is locally exposed to white can be prevented.

A sectional view of the case base to which the appearance film is attached may be as shown in (c) of fig. 7.

S400: ink spraying treatment is carried out on the shell matrix attached with the appearance membrane

In this step, the entire surface of the concave surface of the case base to which the exterior film is attached is subjected to ink spraying. That is, a whole layer of ink is formed on the inner surface of the side wall of the housing base, the surface of the boundary ink layer and the surface of the appearance color layer. The ink sprayed in the step can be any one of polyurethane or polyacrylic ink, and the ink has good adhesive force with the appearance membrane and the plastic base material. A sectional view of the case base after ink is ejected may be as shown in (d) of fig. 7.

Specifically, the color of the ink sprayed in this step may or may not be consistent with the appearance of the film. When the color of the ink sprayed on the shell is consistent with that of the appearance membrane, better appearance consistency can be obtained, and when the color of the ink sprayed on the shell is inconsistent with that of the appearance membrane, a shell assembly with inconsistent color of the side wall frame of the shell and the back cover of the shell can be formed. But because the casing base body is a whole, the casing assembly can also have better uniformity, and is different from the casing which is formed by splicing the rear casing and the side wall in the related art into a whole.

According to some specific examples of the present application, the ink after spraying may be baked. For example, the inner surface of the shell substrate after the appearance membrane is attached can be subjected to twice ink spraying and twice baking, the thickness of each layer of ink can be 10-15 μm, the ink baking temperature can be 80 ℃, and the time can be 30 min. Thus, a firmly bonded ink layer can be formed. In addition, because the bottom surface is covered by the appearance membrane, and the position with a larger bending angle is covered by the boundary line ink layer, the ink layer formed in the step can have better production yield even if the inner surface of the whole shell base body is covered, and the defects of folds, cracks after use and the like at the bending angle where the side wall is contacted with the bottom surface are relieved and even solved.

In some examples of the present application, the housing substrate after forming the ink layer may have a grade of 4B or more as a result of the one-hundred-grid test, and a grade of 3B or more as a result of the one-hundred-grid test after being boiled in water at 100 ℃ for 30min (determined according to astm D3002D 3359).

According to some examples of the present application, in order to further improve the quality of the housing assembly prepared using the method, referring to fig. 3, the method may further include:

s500: performing surface hardening treatment on the shell substrate with the ink layer

According to an example of the present application, the surface hardening treatment may be performed in this step by specifically using a process of spraying a UV hardening liquid. Specifically, the main component of the hardening liquid can be urethane acrylate and an initiator, and the mass ratio of the urethane acrylate to the initiator can be 100 (3-8). The hardening liquid can be sprayed and cured in two times, and the total spraying thickness of the hardening liquid is 5-30 μm, for example, 20-30 μm. The UV curing energy is 600-900mJ, and the time is 10-20 seconds. Thereby, the hardness of the surface of the base body of the case can be further enhanced, while the defects caused by the hardening treatment at the initial stage of the production like in the related art can be avoided.

In yet another aspect of the present application, a housing assembly is provided. The housing assembly is prepared by the method described above. Thus, the housing assembly has all the features and advantages of the housing prepared by the method described above, and thus, the description thereof is omitted. Generally, the shell assembly can realize the integration of the rear shell and the middle frame, and has better appearance consistency at the rear shell and the middle frame. As shown with reference to fig. 4 to 6 and (d) of fig. 7, the housing assembly may specifically include: the housing body 100 has a bottom surface 110, and 4 sidewalls (120A-120D) surrounding the bottom surface 110, and a receiving space is defined between the sidewalls 120 and the bottom surface 110. The appearance film 300 is disposed on the surface of the bottom surface 110 facing the accommodating space, and the boundary ink layer 200 is disposed on the surface of the bottom surface on the side of the appearance film and at the boundary between the bottom surface and the sidewall. The edge of the boundary ink layer 200 facing the bottom coincides with the edge of the appearance film 300. The ink layer 400 covers the surface of the side wall facing the accommodating space and the surface of the appearance membrane 300 and the boundary ink layer 200 facing away from the housing base. Therefore, the shell can realize the integration of the rear shell and the middle frame, and the rear shell and the middle frame can have better appearance consistency. The shell is simple in structure, convenient to prepare, and capable of achieving good product yield and further achieving low production cost.

It should be noted that, in the present application, the phrase "the edge of the boundary line ink layer facing the bottom surface coincides with the edge of the appearance film" should be understood in a broad sense, and may be an area where the edge of the boundary line ink layer 200 facing the bottom surface coincides with the edge of the appearance film 300, and there is no coverage area between the boundary line ink layer and the appearance film, and the surface of the housing base 100 is not covered by the boundary line ink layer or the appearance film at the boundary between the bottom surface and the side wall. Alternatively, the boundary ink layer 200 and the edge of the appearance film may have a small overlapping area, and the appearance film is stacked on the boundary ink layer.

Specifically, the boundary line ink layer and the edge of the appearance membrane have an overlapping area, and the extending length of the overlapping area along the direction extending from the edge perpendicular to the bottom surface is not more than 0.25 mm. The design film in the overlap region is located on the side of the boundary ink layer facing away from the housing base.

According to some examples of the present application, at a corner between two adjacent side walls, a bending angle between the bottom surface and the side wall is not less than 70 degrees;

optionally, the color of the ink layer may correspond to the color of the appearance film. The ink layer may include any one of polyurethane ink and polyacrylic ink, and specifically, the ink layer may include two sublayers subjected to a curing treatment.

In yet another aspect of the present application, an electronic device is provided. According to an embodiment of the present application, referring to fig. 7, an electronic device 2000 includes: the housing assembly 1000 described above, as well as a display and a motherboard (not shown). Display screen and mainboard link to each other, and the display screen all accomodates in casing assembly's accommodation space with the mainboard. From this, this electronic equipment's casing subassembly's outward appearance effect is preferred, and outward appearance expressive force is good, can further promote electronic equipment's whole outward appearance effect.

In particular, the housing assembly may be unitary, with the functions of a rear cover and a center frame. Specifically, referring to fig. 7, the housing assembly may have 4 side walls and 1 bottom surface, the side walls may have structures including, but not limited to, a volume key through hole 10, a charging socket 30, etc., and the bottom surface may further have a camera hole 20. The camera hole 20 may be a through hole penetrating the entire housing assembly, or an appearance membrane of the housing assembly may be hollowed out at the camera hole 20.

The specific type of the electronic device is not limited, for example, the electronic device includes, but is not limited to, a mobile phone, a notebook, an iPad, a kindle, and the like. In some embodiments of the present application, the electronic device 2000 is a mobile phone.

It will be understood by those skilled in the art that the electronic device includes, in addition to the housing assembly, the structures or components necessary for the conventional electronic device, and in addition to the housing assembly, the mobile phone includes, for example, the structures or components necessary for the conventional mobile phone, such as a glass cover, a display panel, an audio processing module, a camera module, and a touch screen.

The present application is described below by way of specific examples, and those skilled in the art will appreciate that the following specific examples are for illustrative purposes only and do not limit the scope of the present application in any way. In addition, in the following examples, materials and equipment used are commercially available unless otherwise specified. If in the examples that follow, specific processing conditions and processing methods are not explicitly described, processing may be performed using conditions and methods known in the art.

Example 1

And performing injection molding by adopting optical-grade polymethyl methacrylate to form a shell matrix with a bending angle between the side wall and the bottom surface of 80 degrees. By two times of pad printing, a boundary line ink layer with the width of 0.8mm is formed, and the thickness of the boundary line ink layer is 10 microns. After each pad printing of the ink, the curing baking is carried out for 30min at 80 ℃.

The UV transfer printing layer (thickness is 8 microns) and the optical coating layer (TiO) are added₂-SiO₂-TiO₂Film system, thickness 400nm), appearance film (base material is PET) of cover bottom ink layer and boundary line oilAnd adhering the shell substrate of the ink layer. Wherein the edge of the appearance membrane is reserved with an amplification allowance of 0.2mm relative to the boundary line ink layer. The bonding conditions were: the attaching temperature is 30 ℃, the attaching time is 30s, and the deformation of the attached silica gel is 2 mm. After the bonding is finished, defoaming treatment is carried out, wherein the defoaming pressure is 6kgf, the defoaming temperature is 50 ℃, and the defoaming time is 20 min.

And spraying ink on the shell substrate attached with the appearance membrane to form an ink layer, wherein the color of the ink layer is consistent with that of the appearance membrane. Spraying twice and baking twice, wherein the thickness of each layer of printing ink is 12 mu m, the temperature for baking the printing ink is 80 ℃, and the time is 30 min.

And finally, hardening to obtain the shell assembly.

Example 2

The rest steps are the same as the embodiment 1, except that the color of the ink layer formed by spraying is not consistent with that of the appearance membrane, but is consistent with that of the boundary ink layer.

Example 3

The rest of the steps are the same as the embodiment 1, except that no allowance is reserved for the cut appearance membrane.

Comparative example 1

The other steps are the same as example 1, except that the preparation of the boundary ink layer is not performed, and the ink is directly sprayed to form the ink layer covering the whole inner surface of the shell substrate after the appearance membrane is attached.

Comparative example 2

The other steps are the same as example 1, except that the boundary ink layer is prepared after the appearance film is attached. The appearance membrane and the boundary line ink layer have an overlapping area, but the appearance membrane is positioned between the boundary line ink layer and the shell substrate.

Comparative example 3

The rest of the procedure was the same as in example 1, except that the ink layer was not sprayed on the entire inner surface, but only on the sidewalls.

100 pieces of housing assemblies were prepared according to the protocols described in examples 1 to 3 and comparative examples 1 and 2, respectively, and the production yield was counted for each protocol. Examples 1 and 2 have the highest production yield, and the housing assembly has the least number of cracks and blisters at the side walls and the R-corners. Example 3 yield was slightly lower than examples 1 and 2, and mainly the case components appeared white due to inaccurate fitting, but the number of case components with cracks and blisters appearing on the side walls and at the corners R was still less than the solutions described in comparative examples 1 and 2.

Although the number of the case assembly in which cracks and blisters occurred at the side wall and the R corner of the case assembly prepared in comparative example 1 was less than that of comparative example 2, the obtained case assembly had a distinct boundary between the side wall and the bottom surface and a poor visual effect. In comparative example 2, the number of poor casing substrates was the largest, and the boundary ink layer was wrinkled, broken, and the like, which resulted in a large influence on the side wall and the R-corner appearance of the casing.

In the description of the present application, the terms "upper", "lower", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of describing the present application but do not require that the present application must be constructed and operated in a specific orientation, and thus, cannot be construed as limiting the present application.

In the description herein, references to the description of "one embodiment," "another embodiment," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment is included in at least one embodiment of the application. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Although embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present application, and that variations, modifications, substitutions and alterations may be made to the above embodiments by those of ordinary skill in the art within the scope of the present application.

Claims

1. A method of making a housing assembly, comprising:

preparing a housing base body which is formed by a transparent material and comprises a bottom surface and 4 side walls surrounding the bottom surface, wherein the bottom surface and the side walls define a containing space on the inner side of the housing base body;

forming a boundary line ink layer on the surface of the bottom surface of the shell substrate facing one side of the accommodating space, wherein the boundary line ink layer is positioned at the boundary between the bottom surface and the side wall;

attaching an appearance membrane on the bottom surface, and enabling the boundary of the appearance membrane to coincide with the edge of one side, facing the bottom surface, of the boundary line ink layer;

and carrying out ink spraying treatment on the shell substrate attached with the appearance membrane so as to form an ink layer on one side of the side wall facing the accommodating space, the surface of the boundary ink layer and the surface of the appearance membrane far away from the shell substrate.

2. The method of claim 1, wherein the preparing the housing base comprises:

performing injection molding treatment on the transparent plastic to obtain a rough blank of the shell substrate;

carrying out finishing treatment on the rough blank of the shell substrate to form the shell substrate,

optionally, the transparent plastic comprises at least one of optical grade polymethylmethacrylate and optical grade polycarbonate;

optionally, the finishing treatment is performed by using a numerically controlled machine tool, and the machining precision of the finishing treatment is ± 8 μm.

3. The method of claim 2, wherein the injection molding process comprises:

heating the transparent plastic to be molten, injecting the molten transparent plastic into an injection mold at an injection pressure of 100-150MPa, wherein the injection time is 2-4s, and carrying out pressure-maintaining molding at a pressure-maintaining molding pressure of 40-50MPa, and the pressure-maintaining molding time is 30-40 s.

4. The method of claim 1, wherein the boundary ink layer is formed by pad printing using a soft head at the boundary between the bottom surface and the sidewall,

optionally, forming the boundary ink layer comprises performing the pad printing a plurality of times, wherein the thickness of the ink formed by each pad printing is 5-14 μm,

optionally, the width of the boundary ink layer is 0.6-1 mm;

optionally, the pad printing further comprises: and carrying out solid baking treatment on the pad printing ink, wherein the temperature of the solid baking treatment is 65-85 ℃, and the time is 20-45 minutes.

5. The method of claim 1, wherein forming the appearance film sheet comprises at least one of:

carrying out UV transfer printing on the transparent film substrate to form an optical texture layer;

forming an optical coating layer on the transparent film substrate;

printing a bottom ink layer on the transparent film substrate on which at least one of the optical texture layer and the optical coating layer is formed by silk-screen printing, wherein the bottom ink layer is formed on the surface of one side of the optical texture layer or the optical coating layer away from the transparent film substrate;

and carrying out laser cutting on the transparent film base material to obtain the appearance film with the shape matched with the bottom surface.

6. The method as claimed in claim 5, wherein the optical texture layer is formed by UV-curable adhesive, the UV-curable adhesive comprises urethane acrylate, the thickness of the UV-curable adhesive is 7-9 μm, and the UV-curable adhesive is cured at a UV irradiation energy of 1000-.

7. The method according to claim 5, wherein the optical coating is formed by evaporation or sputtering,

optionally, the optical coating layer comprises a single-layer metal film, the single-layer metal film is formed by In or alloy of In and Sn, the thickness of the single-layer metal film is 20-30nm,

or the optical coating layer comprises a plurality of sub-layers which are sequentially laminated, the total thickness of the optical coating layer is 100-500nm, and the sub-layers comprise TiO₂And SiO₂Or said sublayer comprises Nb₂O₅And SiO₂。

8. The method according to claim 5, wherein the hiding ink layer comprises a plurality of ink sub-layers, each of the ink sub-layers having a thickness of 6-8 μm;

the silk screen printing forms the end of lid printing ink layer and further includes: and baking the transparent film substrate printed with the cover bottom ink at the baking temperature of 65-90 ℃ for 20-45 min.

9. The method according to claim 5, wherein the transparent film substrate is laser cut so that the side length of the appearance film is 0.25 to 0.15mm larger than the side length of the bottom surface.

10. The method of claim 1, wherein the application of the design film to the first surface of the bottom surface is performed by vacuum application, and the design film is subjected to a heat treatment during the application;

optionally, the temperature for heating the appearance membrane is 25-40 ℃, and the attaching time is 20-40 s;

optionally, after the attaching, the method further comprises: and (4) defoaming, wherein the defoaming pressure of the defoaming treatment is 4-6.5kgf, the defoaming temperature is 45-55 ℃, and the defoaming time is 15-25 min.

11. The method of claim 1, wherein the ink layer has a color that corresponds to the color of the appearance film;

optionally, the ink layer includes any one of a polyurethane-based ink and a polyacrylic-based ink;

optionally, forming the ink layer comprises: and spraying ink on the shell substrate attached with the appearance membrane, wherein the thickness of the sprayed ink is 10-15 mu m, curing and baking the sprayed ink at the temperature of 70-90 ℃ for 20-45min, and repeating the operations of spraying the ink and curing and baking the sprayed ink again.

12. The method of any one of claims 1-11, further comprising:

carrying out surface hardening treatment on the shell substrate on which the ink layer is formed,

optionally, the surface hardening treatment is achieved by spraying a hardening liquid, and the thickness of the hardening liquid coating is 5-20 μm.

13. A housing component, characterized in that it is produced by a method according to any one of claims 1-12.

14. A housing assembly, comprising:

the shell body is provided with a bottom surface and 4 side walls surrounding the bottom surface, and an accommodating space is defined between each side wall and the bottom surface;

an appearance membrane disposed on a surface of the bottom surface on a side facing the accommodation space;

the boundary line ink layer is positioned on the surface of the bottom surface, which is arranged on one side of the appearance membrane, and is positioned at the boundary position between the bottom surface and the side wall, and the edge of the boundary line ink layer, which faces one side of the bottom surface, is superposed with the edge of the appearance membrane; and

the ink layer covers the surface of one side, facing the accommodating space, of the side wall, and the surface of one side, away from the shell base, of the appearance membrane and the boundary line ink layer.

15. The housing assembly of claim 14, wherein a bending angle between the bottom surface and the side wall at a corner between two adjacent side walls is not less than 70 degrees;

optionally, the color of the ink layer is consistent with that of the appearance membrane, the ink layer comprises any one of polyurethane ink and polyacrylic acid ink, and the ink layer comprises two sublayers subjected to curing treatment;

optionally, the boundary ink layer and the edge of the appearance membrane have an overlapping region therebetween, the overlapping region extends along a direction perpendicular to the edge of the bottom surface by a length of not more than 0.25mm, and the appearance membrane at the overlapping region is located on a side of the boundary ink layer away from the housing base.

16. An electronic device, comprising:

the housing assembly of any one of claims 13-15;

display screen and mainboard, the display screen with the mainboard links to each other, just the display screen with the mainboard all accomodate in casing subassembly's accommodation space.