A ceramic composite middle frame and preparation method thereof

Abstract

The present invention discloses a ceramic composite middle frame and a preparation method thereof, comprising a supporting member, an antenna layer and a ceramic frame, wherein the antenna layer is connected to the supporting member through a first plastic member; and the ceramic frame is connected to the antenna layer through a second plastic member. The ceramic composite middle frame of the present invention reserves an interlayer for accommodating an antenna between the first plastic member and the second plastic member, provides an arrangement space for the antenna and the antenna contact, and achieves the purpose of adding antenna contacts in the ceramic middle frame and reasonably arranging the antenna. Compared with the existing antenna layout method for the ceramic middle frame, it is more reasonable, simple, and saves internal space, and will not affect the design of the screen size. In addition, due to the firm bonding surface formed between the first plastic member and the second plastic member, the antenna layer is not easy to fall off, which has achieved significant progress compared with the prior art.

Description

Technical Field

[0001] The invention belongs to the technical field of electronic product parts processing, and in particular relates to a ceramic composite middle frame and a preparation method thereof. Background Art

[0002] The electronic device middle frames on the market are mainly metal middle frames and ceramic middle frames. The color effects that can be achieved on the surface of the metal middle frame are very limited, and the reliability is poor. At the same time, in order to transmit signals to the antenna, the antenna contacts need to be formed on the metal middle frame, which requires processes such as nano injection molding, CNC finishing and anodizing. The overall process is complicated and the durability is poor. Moreover, the antenna layout of the metal middle frame is arranged in a way that the frame is separated by plastic strips, which can be distinguished in appearance, which has a great impact on the appearance effect.

[0003] The appearance of the middle frame made of ceramic has a texture as smooth as jade, hard and wear-resistant; at the same time, ceramic powder can achieve CMF appearance effects such as color, matte, glaze, and dazzling, and has good durability. However, for the ceramic middle frame, due to the material properties of the ceramic itself, it has high strength and is difficult to process. It is difficult to directly carry out a variety of metallization design schemes on the ceramic middle frame. As a result, the antenna layout of existing electronic products with ceramic middle frames is to leave a clearance area for the antenna under the screen, which affects the screen size design, and the antenna contacts are all installed on the back panel of the electronic product or under the screen. At present, there is a design that directly makes the LDS antenna inside the ceramic frame, but there are defects such as poor bonding strength, unclear antenna boundary lines, and failure to meet the subsequent processing performance requirements of the ceramic frame. Therefore, in response to the above problems, there is an urgent need for a new solution for the antenna layout of the ceramic middle frame. Summary of the invention

[0004] Based on this, in order to solve the above technical problems, the present invention aims to provide a ceramic composite middle frame and a preparation method thereof.

[0005] In order to achieve the above-mentioned invention object, the present invention adopts the following solution: a ceramic composite middle frame, comprising:

[0006] A supporting member, wherein the supporting member is a metal plate;

[0007] The antenna layer is connected to the support member through a first plastic member; wherein the first plastic member is in a non-closed ring shape and is arranged around the support member;

[0008] A ceramic frame connected to the antenna layer via a second plastic component; wherein the second plastic component is ring-shaped and arranged around the ceramic frame;

[0009] More preferably, the support member is provided with at least one first connection part, and the first plastic member is provided with a second connection part matching therewith. The first connection part and the second connection part may be mutually matching bite structures or overlap structures. Specifically, when the first connection part is a step / groove, the second connection part is a matching groove / step, and the number of steps and grooves may be multiple. The connection surface size between the first plastic member and the support member is 35 to 200 mm. 2 , the bottom area of ​​the first plastic component is 100-800mm 2 The step depth of the first plastic component is 0.2-3.0 mm, the groove depth is not less than 0.2 mm, and the mass is controlled to be 0.5-3.5 g.

[0010] More preferably, the supporting member is a metal middle plate, which mainly supports the electronic components inside the electronic product and can also serve as a part of the antenna design, such as serving as an antenna grounding point.

[0011] There is a sandwich between the first plastic component and the second plastic component, and the sandwich provides a space for the antenna and is designed to match the antenna layer. More preferably, the sandwich space between the first plastic component and the second plastic component is 2.4mm 3 -32mm 3 The interlayer is 40-100 mm long, 0.3-0.8 mm wide and 0.2-0.4 mm deep.

[0012] Preferably, the antenna layer is a metal layer with a thickness of 0.05-0.3mm. If the thickness of the antenna layer is higher than 0.3mm, it will occupy too much space, increase the difficulty of electronic product design, and increase the weight of the ceramic middle frame, which is not conducive to the requirements of lightweight mobile terminals; if the thickness of the antenna layer is lower than 0.05mm, the processing performance is poor, and it is easy to cause the antenna layer to be weak in strength, or even cause the antenna layer to fall off.

[0013] More preferably, the main material of the antenna layer is aluminum metal.

[0014] More preferably, when the thickness of the antenna layer is 0.05 mm, the designed volume of the antenna layer is 8-25 mm 3 , the antenna layer weighs 0.02 to 0.07 g.

[0015] More preferably, when the thickness of the antenna layer is 0.1 mm, the designed volume of the antenna layer is 16-50 mm 3 , the antenna layer weighs 0.04 to 0.14 g.

[0016] More preferably, when the thickness of the antenna layer is 0.15 mm, the designed volume of the antenna layer is 25-75 mm 3, the antenna layer weighs 0.07 to 0.21 g.

[0017] More preferably, when the thickness of the antenna layer is 0.2 mm, the designed volume of the antenna layer is 30-100 mm 3 , the antenna layer weighs 0.08 to 0.28 g.

[0018] More preferably, when the thickness of the antenna layer is 0.3 mm, the designed volume of the antenna layer is 50 to 150 mm 3 , the antenna layer weighs 0.14 to 0.42 g.

[0019] Preferably, the antenna layer has a boss, which serves as a connection point (antenna contact) between the antenna layer and the antenna circuit design, and has a height of 0.2-0.4 mm. If the boss height is higher than 0.4 mm, it will occupy too much space and increase the difficulty of electronic product design; if it is lower than 0.2 mm, its protruding height is not obvious, which may easily cause poor contact of the antenna connection line.

[0020] Preferably, the side area of ​​the antenna layer is 50-300mm 2 The antenna layer is 45-50 mm long, 1-6 mm wide, and has 5-30 antenna contacts (protrusions). The side surface of the antenna layer can be understood as the side surface of the antenna layer that is perpendicular to the bottom surface of the mobile phone back panel.

[0021] Preferably, the constituent material of the first plastic component and the constituent material of the second plastic component have the same main body, so that a secure bonding surface can be formed between the first plastic component and the second plastic component.

[0022] Preferably, the melting point temperature of the material constituting the second plastic member is higher than or equal to the melting point temperature of the material constituting the first plastic member.

[0023] More preferably, the difference between the melting point temperature of the material constituting the second plastic component and the melting point temperature of the material constituting the first plastic component is ≤30°C;

[0024] More preferably, the difference between the melting point temperature of the material constituting the second plastic component and the melting point temperature of the material constituting the first plastic component is 10°C-30°C.

[0025] Preferably, the first plastic component and the second plastic component are made of at least one of PA, PARA, PBT and PC.

[0026] More preferably, the first plastic component is made of PBT, and the second plastic component is made of PA, and the difference in melting points is 15-25°C.

[0027] More preferably, the first plastic component is made of PARA1#, and the second plastic component is made of PC, and the melting point difference is 0-20°C.

[0028] More preferably, the first plastic component is made of PBT, and the second plastic component is made of PARA1#, and the melting point difference is 15-25°C;

[0029] More preferably, the first plastic component is made of PARA1#, and the second plastic component is made of PARA2#, and the difference in melting points is 10-30°C.

[0030] The main materials of PARA1# and PARA2# are both PARR, the difference is that the glass fiber content is different, which is 30% and 50% respectively.

[0031] In this article, the present invention can strengthen the adhesion of the connection surface by setting a certain melting point difference between the constituent material of the first plastic component and the constituent material of the second plastic component. Because when the melting point temperature of the constituent material of the second plastic component is too low, it cannot melt the surface of the first plastic component, and the effect of chemical bonding cannot be achieved, and the bonding between the two is not strong; if the melting point temperature of the constituent material of the second plastic component is too high, the first plastic component will soften and deform, and in severe cases, the second plastic component will penetrate the first plastic component, resulting in processing failure. The inventor has found through a large number of experimental explorations that when the melting point difference between the constituent material of the first plastic component and the constituent material of the second plastic component is ≤30°C, a reliable bonding surface can be formed between the plastic components, and the appearance is better. This effect is optimal when the melting point difference between the constituent material of the first plastic component and the constituent material of the second plastic component is 10°C-30°C. At this time, the bonding force between the two is greater than 25Mpa, and the weld line is smooth after processing, and the structure of the first plastic component does not change.

[0032] Another object of the present invention is to provide a method for preparing the above-mentioned ceramic composite middle frame, comprising the following steps:

[0033] A) processing the ceramic middle frame to obtain a secondary injection molding bonding surface structure of the ceramic middle frame;

[0034] The processing of the ceramic middle frame includes surface treatment of the joint surface of the ceramic middle frame, so that the ceramic middle frame and the second plastic component formed by injection molding are firmly connected, stably and reliably.

[0035] B) processing the support member, including performing a pre-injection molding combined structure processing on the support member to form a first connecting portion; performing a partial hollowing process on the support member to reserve a space for the antenna layer structure;

[0036] The support member is processed to form the first connection part, that is, a groove, a step, etc. are formed on the support member. The processing of the support member includes surface treatment of the joint surface between the support member and the preformed first plastic member, including at least one of surface gluing and T treatment.

[0037] C) performing a one-time injection molding process on the support member to obtain a first plastic member; performing CNC finishing processing on the combined first plastic member and the support member to obtain an antenna layer structure;

[0038] The antenna layer structure includes a metal extension layer and a boss.

[0039] D) placing the first plastic component and the ceramic frame into a mold for overlap preparation, and then performing secondary in-mold injection molding between the ceramic frame and the first plastic component to form a second plastic component;

[0040] E) fine-processing the ceramic frame to obtain the ceramic composite middle frame.

[0041] The finishing includes shape finishing, position finishing and appearance polishing.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] The ceramic composite middle frame of the present invention reserves an interlayer for accommodating the antenna layer between the first plastic component and the second plastic component, thereby providing a layout space for the antenna and the antenna contact, achieving the purpose of adding antenna contacts and reasonably arranging the antenna in the ceramic middle frame. This design does not affect the design of the screen size, and is more reasonable and simple than the existing antenna layout method for the ceramic middle frame, and saves internal space. In addition, due to the firm bonding surface formed between the first plastic component and the second plastic component, the antenna layer is not easy to fall off, which has achieved significant progress compared with the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a schematic diagram of the planar structure of the composite middle frame of the present invention;

[0045] Figure 2 A cross-sectional view of the composite middle frame of the present invention;

[0046] Figure 3 It is an exploded view of the local structure of the composite middle frame of the present invention;

[0047] Figure 4 This is a partial three-dimensional diagram of the composite middle frame of the present invention.

[0048] In the figure, there are a ceramic frame 1 , a metal middle plate 2 , an antenna layer 3 , an antenna contact 301 , a first plastic component 4 , and a second plastic component 5 . DETAILED DESCRIPTION

[0049] The above contents of the present invention are further described in detail below through specific implementation methods in the form of embodiments, but this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments.

[0050] In the examples, the experimental methods used are conventional methods unless otherwise specified, and the materials, reagents, etc. used are all commercially available unless otherwise specified.

[0051] Embodiment 1: A ceramic composite middle frame

[0052] like Figures 1 to 4 As shown, Figure 1 It shows a schematic diagram of the planar structure of the middle frame described in the first embodiment of the present invention; Figure 2 A cross-sectional view of a composite middle frame of an embodiment of the present invention is shown. The composite middle frame of the present invention includes a metal middle plate 2, an antenna layer 3 and a ceramic frame 1. The antenna layer is connected to the metal middle plate through a first plastic component 4; wherein the first plastic component is in a non-closed ring shape and is arranged around the metal middle plate; the ceramic frame is connected to the antenna layer through a second plastic component 5; wherein the second plastic component can be in a non-closed or closed ring shape and is arranged around the ceramic frame.

[0053] The metal middle plate generally includes a mounting plate for accommodating electronic devices. At the same time, in order to connect with the first plastic component, at least one first connecting portion is usually provided on the metal middle plate, and the first plastic component is provided with a second connecting portion matching therewith (not shown in the figure of the present invention). In this embodiment, the first connecting portion can be a step or a groove, and the second connecting portion is a matching groove or a step. The number of steps and grooves can be multiple. In this embodiment, the number of steps is 8. The size of the connection surface between the first plastic component and the metal middle plate is 110mm 2 .

[0054] The antenna layer is a metal layer in this embodiment with a thickness of 0.2 mm. The antenna layer has a boss, which serves as a connection point between the antenna layer and the antenna circuit design, namely, the antenna contact 301, with a height of 0.25 mm. The side area of ​​the antenna layer is 210 mm 2 The antenna layer is about 50 mm long and 4.2 mm wide, and has 12 antenna contacts (bosses).

[0055] The first plastic component mainly serves to connect the metal middle plate and the antenna layer. There is a sandwich between the first plastic component and the second plastic component. The sandwich provides a space for the antenna layer and is designed to match the antenna layer. The sandwich is 72mm long, 0.45mm wide, and 0.25mm deep. The bottom area of ​​the first plastic component is 500mm 2 .

[0056] The second plastic component is mainly used to connect the antenna layer and the ceramic frame. In this embodiment, the material of the first plastic component is PBT, whose melting point is 235°C, and the material of the second plastic component is PA, whose melting point is 245°C. The difference in melting points is 10°C, and the bonding force formed by the two is 31.34Mpa.

[0057] The preparation method of the ceramic composite middle frame of the present invention:

[0058] Step 1): The ceramic frame is ground to obtain the outer injection molding reference size of the ceramic frame, and the ceramic frame secondary injection molding bonding surface (glue drawing) structure is obtained through CNC finishing;

[0059] Step 2): Activate the surface of the ceramic frame joint surface, and apply a layer of organic glue layer on the ceramic frame. The organic glue layer is epoxy resin, which serves as a binder between the ceramic and the second plastic component, and plays a role in connecting the injection-molded ceramic and the second plastic component;

[0060] Step 3): The metal middle plate is combined with structural processing before the first injection molding to obtain the surface structure of the middle plate, including grooves, steps, etc. At the same time, a local hollowing process is performed at the fixed position of the metal middle plate to reserve the antenna layer structure, and a T treatment is performed on the first injection molding bonding surface of the metal middle plate;

[0061] Step 4): The metal middle plate is subjected to a first injection molding to obtain an injection-molded middle plate; the injection-molded middle plate is subjected to CNC finishing to obtain an antenna layer structure and an antenna contact structure on the inner side of the plastic middle plate;

[0062] Step 5): connecting the injection-molded middle plate to the ceramic frame after surface activation treatment; performing secondary in-mold injection molding on the ceramic frame and the injection-molded middle plate;

[0063] Step 6): The ceramic frame is subjected to shape finishing, position finishing and appearance polishing to obtain the ceramic composite middle frame.

[0064] Embodiment 2: A ceramic composite middle frame

[0065] The difference between the second embodiment of the present invention and the first embodiment is that the constituent material of the first plastic component is PARA1#, the constituent material of the second plastic component is PC, the melting point difference is 5° C., and the other parameters are the same as those of the first embodiment.

[0066] Embodiment 3: A ceramic composite middle frame

[0067] The difference between the third embodiment of the present invention and the first embodiment is that the constituent material of the first plastic component is PBT, the constituent material of the second plastic component is PARA1#, the melting point difference is 20° C., and the other parameters are the same as those of the first embodiment.

[0068] Embodiment 4: A ceramic composite middle frame

[0069] The difference between the fourth embodiment of the present invention and the first embodiment is that the constituent material of the first plastic component is PARA1#, the constituent material of the second plastic component is PARA2#, the melting point difference is 20° C., and the other parameters are the same as those of the first embodiment.

[0070] Comparative Example 1: A Ceramic Composite Middle Frame

[0071] The difference between Comparative Example 1 of the present invention and Example 1 is that the constituent material of the first plastic component is PP, the constituent material of the second plastic component is PC, the melting point difference is 90° C., and the other parameters are the same as those of Example 1.

[0072] Comparative Example 2: A Ceramic Composite Middle Frame

[0073] The difference between the comparative example 2 of the present invention and the embodiment 1 is that the constituent material of the first plastic component is PP, the constituent material of the second plastic component is PARA1#, the melting point difference is 85° C., and the other parameters are the same as those of the embodiment 1.

[0074] Note: The difference between PARA1# and PARA2# in the above embodiments is that the glass fiber content is different, which is 30% and 50% respectively.

[0075] Test Example 1: Effect of different melting point differences on product appearance and bonding strength between components

[0076] The composite middle frame prepared in the above-mentioned embodiments 1 to 4 and comparative examples 1 to 2, the materials and melting point ranges of the first plastic component and the second plastic component involved in the embodiments 1 to 4 and comparative examples 1 to 2 are shown in Table 1, and the appearance and the bonding strength between the first plastic component and the second plastic component are tested. The test results are shown in Table 2 below.

[0077] Table 1 Materials and melting points of the first plastic component and the second plastic component involved in Examples 1 to 4 and Comparative Examples 1 to 2

[0078]

[0079] Table 2 Test results

[0080]

[0081]

[0082] Note: The appearance test method is naked eye observation and CCD projection observation; the bonding strength test method is pull-out force test.

[0083] It can be seen from Table 2 above that when the melting point temperature difference between the constituent material of the first plastic component and the constituent material of the second plastic component is between 10-30°C, it is found that the weld line between the two components is smooth and the structure of the first plastic component does not change; at the same time, it can be seen from Comparative Examples 1 and 2 that when the melting point difference is higher than 30°C, the second plastic component is overcharged, the weld line becomes wavy, and the structure of the first plastic component is damaged.

[0084] Test Example 2: Antenna Layer Thickness Test

[0085] The present invention provides embodiments five to nine and comparative examples three to four, wherein the structures and preparation methods of embodiments five to nine and comparative examples three to four can be seen in embodiment one, the difference is that the antenna layer structure has the same shape, but different thickness parameters, resulting in different antenna layer volumes and antenna layer weights, and the RF signal performance is evaluated, and the specific situation is shown in Table 3.

[0086] The bonding conditions between the antenna layer and the first plastic component in Examples 5 to 9 and Comparative Examples 3 to 4 were measured respectively. The specific test method was to perform a pull-out force test. When the stress reached 25 MPa, if the antenna layer and the first plastic component were not separated, it indicated that the bonding between the two was good; otherwise, the bonding was poor. The specific test results are shown in Table 3.

[0087] Table 3 Test results

[0088]

[0089]

[0090] It can be seen from Table 3 above that in Comparative Example 4, the thickness of the antenna layer is 0.5mm, and its volume is 11-75 times that of Examples 7-9, and its weight is significantly higher than that of other examples. It can be seen that a slight change in the thickness of the antenna layer will directly and significantly affect the weight of the antenna layer and even the weight of the entire mobile terminal. Moreover, if the antenna layer is too thin, on the one hand, the space in which the antenna can be designed is limited, which seriously affects the performance of the antenna in the mobile terminal; on the other hand, the bonding strength of the antenna layer is significantly reduced, which can easily cause signal interference or loss. If the antenna layer is too thick, it will obviously compress the available space inside the mobile phone. Moreover, the thickness of the antenna layer of the present invention is set to between 0.05-0.3mm, and its performance can meet the transmission requirements of mobile phone signals, and the antenna layer and the first plastic component are well bonded to meet actual use requirements.

[0091] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the technology may modify or change the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by a person with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A ceramic composite middle frame, characterized in that: include: A supporting member, wherein the supporting member is a metal plate; The antenna layer is connected to the support member through a first plastic member; wherein the first plastic member is in a non-closed ring shape and is arranged around the support member; A ceramic frame connected to the antenna layer via a second plastic component; wherein the second plastic component is ring-shaped and arranged around the ceramic frame; There is an interlayer between the first plastic component and the second plastic component, and the interlayer provides a storage space for the antenna and is designed to match the antenna layer; The melting point of the material of the second plastic component is higher than that of the first plastic component; The antenna layer has a boss, and the boss serves as a connection point between the antenna layer and the antenna circuit design. The antenna layer is a metal layer, and its thickness is 0.05-0.3 mm.

2. The ceramic composite middle frame according to claim 1, characterized in that: The height of the boss is 0.2-0.4 mm.

3. The ceramic composite middle frame according to claim 1, characterized in that: The interlayer space between the first plastic component and the second plastic component is 2.4 mm 3 -32mm 3 .

4. The ceramic composite middle frame according to claim 1, characterized in that: The supporting component is provided with at least one first connecting portion, and the first plastic component is provided with a second connecting portion matching therewith.

5. The ceramic composite middle frame according to claim 1, characterized in that: The first plastic member and the second plastic member are mainly composed of the same material.

6. The ceramic composite middle frame according to claim 1, characterized in that: The difference between the melting point temperature of the material constituting the second plastic component and the melting point temperature of the first plastic component is ≤30°C.

7. The ceramic composite middle frame according to claim 6, characterized in that: The difference between the melting point temperature of the material constituting the second plastic component and the melting point temperature of the material constituting the first plastic component is 10° C.-30° C.

8. The ceramic composite middle frame according to claim 1, characterized in that: The first plastic component and the second plastic component are made of at least one of PA, PARA, PBT and PC.

9. The ceramic composite middle frame according to claim 8, characterized in that: The first plastic member is made of PBT, and the second plastic member is made of PA.

10. A method for preparing the ceramic composite middle frame according to any one of claims 1 to 9, characterized in that: The following steps are involved: A) processing the ceramic middle frame to obtain a secondary injection molding bonding surface structure of the ceramic middle frame; B) processing the support member, including performing a pre-injection molding combined structure processing on the support member to form a first connecting portion; performing a partial hollowing process on the support member to reserve a space for the antenna layer structure; C) performing a primary injection molding process on the support component to obtain a first plastic component; performing CNC finishing on the first plastic component to obtain an antenna layer structure; D) placing the first plastic component and the ceramic frame into a mold, and then performing secondary in-mold injection molding between the ceramic frame and the first plastic component to form a second plastic component; E) fine-processing the ceramic frame to obtain the ceramic composite middle frame.

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