Electromagnetic shielding cover and circuit board

Abstract

The utility model discloses an electromagnetic shielding cover and a circuit board. The electromagnetic shielding cover comprises a shielding layer and an adhesive film layer. The shielding layer and the adhesive film layer are laminated, the shielding layer comprises a flexible layer and a conductive layer, the conductive layer is arranged on the surface of the flexible layer, and the thickness of the conductive layer is 1-8 [mu] m. According to the electromagnetic shielding case and the circuit board provided by the embodiment of the utility model, the structure of the electromagnetic shielding case is improved, so that the electromagnetic shielding case has high toughness while having good shielding performance, and can be attached to the surface of an electronic component on the circuit board, thereby greatly reducing the volume of electronic equipment with the shielding case, and improving the reliability of the electronic equipment. And the development process of miniaturization, lightening and thinning of the electronic equipment is further promoted.

Description

Technical Field

[0001] The utility model relates to the technical field of electronics, in particular to an electromagnetic shielding cover and a circuit board. Background Art

[0002] Electronic components inside an electronic device will continuously emit useless electromagnetic wave signals during operation. These useless electromagnetic wave signals will affect the normal operation of other adjacent electronic components and cause electromagnetic interference. Currently, a metal shielding cover is usually used to cover the electronic device to shield the external electromagnetic wave noise from interfering with the operation of the internal circuit. However, the metal shielding cover occupies a large space, which is not conducive to the integration and miniaturization of the circuit board.

[0003] Now, if the shielding cover is made into a thin film, it is necessary to bond the electromagnetic shielding cover to the printed circuit board during use to achieve the shielding effect. The electromagnetic shielding cover needs to have both electromagnetic shielding properties and flexibility. Nowadays, how to ensure both the shielding performance of the electromagnetic shielding cover during operation and the toughness of the shielding cover is an urgent problem faced by technicians in this industry. Summary of the Utility Model

[0004] The utility model provides an electromagnetic shielding cover and a circuit board. By designing the structure of the electromagnetic shielding cover, while ensuring good shielding performance of the electromagnetic shielding cover, sufficient toughness can be satisfied.

[0005] To solve the above technical problems, an embodiment of the utility model provides an electromagnetic shielding cover, which includes a shielding layer and an adhesive film layer; the shielding layer and the adhesive film layer are stacked, the shielding layer includes a flexible layer and a conductive layer, the conductive layer is on the surface of the flexible layer, and the thickness of the conductive layer is 1μm - 8μm.

[0006] As one of the preferred solutions, the shielding layer is a hollow structure.

[0007] As one of the preferred solutions, the thickness of a single shielding layer is 3μm - 50μm.

[0008] As one of the preferred solutions, the adhesive film layer is composed of an insulating material or conductive adhesive.

[0009] As one of the preferred solutions, the thickness of the adhesive film layer is 2μm - 20μm.

[0010] As one of the preferred solutions, the shielding layer is a single layer or at least two layers of structure.

[0011] As one of the preferred solutions, when the shielding layer is at least two layers of structure, a bonding layer is provided between the shielding layers.

[0012] As one of the preferred solutions, the bonding layer contains conductive particles.

[0013] As one of the preferred solutions, the surface of the shielding layer close to the adhesive film layer has protrusions.

[0014] As one of the preferred solutions, the adhesive layer is made of at least one of thermoplastic polyimide, modified epoxy resin, modified acrylic acid, modified polyurethane, and modified phenolic resin.

[0015] Another embodiment of the present invention provides a circuit board, including a circuit board body and the electromagnetic shielding cover as described above; wherein, the electromagnetic shielding cover is press-fitted with the circuit board body.

[0016] Compared with the prior art, the beneficial effects of the embodiments of the present invention are at least one of the following:

[0017] (1) The electromagnetic shielding cover is closely attached to the surface of the electronic component, greatly reducing the volume of the electronic device with the shielding cover, and thus promoting the development process of miniaturization and lightness and thinness of the electronic device;

[0018] (2) The structure of the electromagnetic shielding cover is improved, so that while the electromagnetic shielding cover has good shielding performance, it also has strong toughness and can be attached to the surface of the electronic components on the circuit board. Description of the Drawings

[0019] Figure 1 is a schematic cross-sectional structure diagram of the electromagnetic shielding cover in one of the embodiments of the present invention;

[0020] Figure 2 is a scanning electron microscope image of the cross-sectional structure of the shielding layer in the embodiment of the present invention;

[0021] Figure 3 is a schematic diagram of the hollow structure on the surface of the conductive layer in the embodiment of the present invention;

[0022] Figure 4 is a schematic structural diagram of the electromagnetic shielding cover in another embodiment of the present invention;

[0023] Figure 5 is a schematic structural diagram of the electromagnetic shielding cover in yet another embodiment of the present invention;

[0024] Reference Signs:

[0025] Among them, 1. shielding layer; 11. conductive layer; 12. flexible layer; 2. adhesive film layer; 3. hollow structure; 4. bonding layer; 5. conductive particles; 6. protrusion; h. height of the protrusion. Detailed Embodiments

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present utility model in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. The purpose of providing these embodiments is to make the disclosure of the present utility model more thorough and comprehensive. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0027] In the description of this application, the terms "first", "second", "third", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", "third", etc. may explicitly or implicitly include one or more of such features. In the description of this application, unless otherwise stated, the meaning of "a plurality" is two or more.

[0028] In the description of this application, it should be noted that unless otherwise clearly specified and defined, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two components. The terms "vertical", "horizontal", "left", "right", "up", "down" and similar expressions used herein are only for the purpose of illustration, rather than indicating or implying that the device or component referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation to the present utility model. The term "and / or" used herein includes any and all combinations of one or more of the related listed items. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0029] In the description of this application, it should be noted that unless otherwise defined, all the technical and scientific terms used in the present utility model have the same meanings as those commonly understood by those skilled in the technical field to which this belongs. The terms used in the description of the present utility model in this specification are only for the purpose of describing specific embodiments, and are not intended to limit the present utility model. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0030] An embodiment of the present utility model provides an electromagnetic shielding cover. Specifically, please refer to Figure 1 , Figure 1 which shows a schematic structural diagram of the electromagnetic shielding cover in one of the embodiments of the present utility model. The electromagnetic shielding cover in this embodiment includes a shielding layer 1 and an adhesive film layer 2 stacked from top to bottom, asFigure 2 As shown, the shielding layer 1 includes a flexible layer 12 and a conductive layer 11. The conductive layer 11 is on the surface of the flexible layer 12, and the thickness of the conductive layer 11 is 1 μm - 8 μm.

[0031] In some embodiments, as Figure 3 shown, the shielding layer 1 is a hollow structure 3. The hollow structure 3 can be a rhombus, polygon, circle, square, rectangle or irregular shape. The hollow structure 3 can be formed by physical or chemical processing methods, or can be a hollow structure 3 formed by laminating multiple shielding layers 1. Exemplarily, the hollow structure 3 can be a hollow structure 3 formed by stacking non-woven fabrics with each other. In addition, the hollow structure 3 can be a blind hole structure or a through hole structure, and this embodiment does not make specific limitations here.

[0032] In some embodiments, the thickness of a single-layer shielding layer 1 is 3 μm - 50 μm. Exemplarily, the thickness of the single-layer shielding layer 1 can be 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 20 μm, 30 μm, 40 μm, 50 μm or an interval composed of any two values. The thickness of the single-layer shielding layer 1 is limited in this embodiment because it will affect the thickness of the entire electromagnetic shielding cover. If the thickness of the single-layer shielding layer 1 is too thick, the overall thickness of the electromagnetic shielding cover will be too thick, which is not conducive to integrated setting; if the thickness of the single-layer shielding layer 1 is too thin, the shielding performance of the electromagnetic shielding cover will be severely reduced, and even shielding failure may occur.

[0033] The adhesive film layer 2 plays a bonding role in the electromagnetic shielding cover, enabling the shielding cover to be firmly bonded to the surfaces of the circuit board and electronic components. The adhesive film layer 2 can be insulating or conductive. The adhesive film layer 2 includes, but is not limited to, polystyrene-based thermoplastic resins, vinyl acetate-based thermoplastic resins, polyester-based thermoplastic resins, polyethylene-based thermoplastic resins, polyamide-based thermoplastic resins, rubber-based thermoplastic resins, acrylate-based thermoplastic resins, phenolic thermosetting resins, epoxy thermosetting resins, thermoplastic polyimide thermosetting resins, urethane thermosetting resins, melamine thermosetting resins, alkyd thermosetting resins, ABF resins. Any adhesive film layer 2 that can meet the bonding requirements is within the scope required by the embodiments of the present invention, and will not be elaborated here. Exemplarily, the adhesive film layer 2 is selected from at least one of modified epoxy resin, modified acrylic resin, polyethylene terephthalate, polybutylene terephthalate, polyethylene, polyethylene naphthalate, polystyrene, polyvinyl chloride, polysulfone, polyphenylene sulfide, polyether ether ketone, polyphenylene ether, polytetrafluoroethylene, liquid crystal polymer, polyoxalylurea, BT resin. Any other bonding layer 4 that can meet the performance requirements is within the scope required by the embodiments of the present invention, and will not be elaborated here. Among them, the thickness of the adhesive film layer 2 is 2μm - 20μm. Exemplarily, the thickness of the adhesive film layer 2 can be 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 16μm, 18μm or 20μm, or any interval composed of two values. The thickness of the adhesive film layer 2 is limited in this embodiment because it will affect the thickness of the entire electromagnetic shielding cover. If the thickness of the adhesive film layer 2 is too thick, the overall thickness of the electromagnetic shielding cover will be too thick, which is not conducive to integrated setting; if the thickness of the adhesive film layer 2 is too thin, the electromagnetic shielding cover will not be firmly bonded and the electromagnetic shielding cover will fall off. In addition, according to actual needs, an insulating layer can be provided on the surface of the shielding layer 1 away from the adhesive film layer 2 to play the role of insulation and protection.

[0034] The shielding layer 1 is a single-layer structure or a multi-layer structure, that is, the electromagnetic shielding cover includes one or more shielding layers 1. Among them, the shielding layer 1 includes a flexible layer 12 and a conductive layer 11. The flexible layer 12 can be a non-metal structure or a metal structure, as long as it can meet sufficient flexibility. Exemplarily, the conductive layer 11 can be laminated on the surface of the flexible layer 12 by physical deposition or chemical deposition methods. Specific methods can be at least one of sputtering, evaporation plating, electroless plating, electroplating, coating, etc. The thickness of the conductive layer 11 is 1 μm - 8 μm. Exemplarily, the thickness of the conductive layer 11 can be 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm or 8 μm, or an interval composed of any two values. Exemplarily, the flexible layer 12 can be one or more of carbon nanotubes, flexible ferrites, graphene, non-woven fabrics, fibers, elastomers, flexible resins. Among them, the materials used for the shielding layers 1 between the multi-layer shielding layers 1 can be the same or a stack of different materials. It should be noted that as Figure 4 shown, a bonding layer 4 is provided between the multi-layer shielding layers 1 to ensure the stable bonding between the shielding layers 1, and conductive particles 5 are provided between the bonding layers 4 to ensure the conduction between the shielding layers 1.

[0035] In some embodiments, as Figure 5 shown, a number of protrusions 6 are distributed on the surface of the shielding layer 1 close to the adhesive film layer 2; the function of the protrusions 6 is to contact the circuit board to achieve the subsequent grounding function. The density of the protrusions 6 is closely related to the conductivity of the electromagnetic shielding cover. A higher density of the protrusions 6 can improve the grounding effect and thus improve the conductivity. However, too high a density will cause a decrease in the amount of sol, which will lead to unstable bonding between the adhesive film layer 2 and the circuit board, and the electromagnetic shielding cover will become loose, affecting the shielding effect. It has been found that in the sectional view, the distribution density of the protrusions 6 is 5×10 2 -1.0×10 4When it is [specific number] per cm, it has an important impact on both conductivity and adhesiveness. It should be noted that the size of the convex portion 6 needs to ensure that it can pass through the adhesive film layer 2 and be connected to the circuit board. Its height h needs to be selected according to the actual product design requirements. In this embodiment, the height h of the convex portion 6 is 2μm - 9μm. Exemplarily, the height h of the convex portion 6 can be 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm or 9μm, or any interval composed of two values. The height h of the convex portion 6 refers to the vertical height h from the lowest bottom corresponding to the contour of a single convex portion 6 to the top of the convex portion 6. The distance between the tops of two adjacent convex portions 6 is 8μm - 50μm. Exemplarily, this distance can be 8μm, 10μm, 12μm, 14μm, 16μm, 18μm, 20μm, 22μm, 24μm, 27μm, 29μm, 31μm, 33μm, 35μm, 37μm, 39μm, 41μm, 43μm, 45μm, 47μm, 49μm or 50μm, or any interval composed of two values.

[0036] It should be noted that the adhesive film layer 2 may or may not contain conductive particles 5. When there are no convex portions 6 in the shielding layer 1, the presence of conductive particles 5 in the adhesive film layer 2 will promote the export of the shielding cover charge, thereby enabling the shielding cover to have higher shielding performance. If there are convex portions 6 in the shielding layer 1, the conductive particles 5 in the adhesive film layer 2 can cooperate with the convex portions 6 in the shielding layer 1 to further improve the grounding performance of the shielding cover.

[0037] Next, some embodiments and comparative examples are listed to elaborate on different embodiments of the present invention in detail, and these specific embodiments and comparative examples are tested.

[0038] Embodiment 1

[0039] An electromagnetic shielding cover includes a shielding layer and an adhesive film layer arranged in a stacked manner. The shielding layer includes an insulating layer, a flexible layer, and a conductive layer. The conductive layer is on the surface of the flexible layer. The thickness of the conductive layer is 1.5μm, and the overall thickness of the shielding layer is about 30μm. The shielding layer is a hollow structure. The adhesive film layer is made of a polyamide thermoplastic resin, and the thickness of the adhesive film layer is 2μm.

[0040] When the electromagnetic shielding cover is pressed onto the circuit board by a conventional process and tested by relevant resistance detection equipment, when the grounding area is 5 square millimeters, the grounding resistance of the electromagnetic shielding cover is less than 500 milliohms, having good shielding performance and strong toughness at the same time, and being able to fit well on the surface of electronic components on the circuit board.

[0041] Embodiment 2

[0042] An electromagnetic shielding cover includes two shielding layers stacked and a glue film layer. The shielding layer includes an insulating layer, a flexible layer, and a conductive layer. The conductive layer is on the surface of the flexible layer. The thickness of the conductive layer is 2.5 μm, and the overall thickness of the shielding layer is about 55 μm. The shielding layer is a hollow structure. A bonding layer is provided between the two shielding layers, and the bonding layer contains conductive particles. The glue film layer is made of acrylic resin, and the thickness of the glue film layer is 2.5 μm.

[0043] When the electromagnetic shielding cover is laminated on the circuit board by conventional processes and tested by relevant resistance detection equipment, when the grounding area is 5 square millimeters, the grounding resistance of the electromagnetic shielding cover is less than 500 milliohms, having good shielding performance. At the same time, it has strong toughness and can fit well on the surface of electronic components on the circuit board.

[0044] Example 3

[0045] An electromagnetic shielding cover includes three shielding layers stacked and a glue film layer. The shielding layer includes an insulating layer, a flexible layer, and a conductive layer. The conductive layer is on the surface of the flexible layer. The thickness of the conductive layer is 4.5 μm, and the overall thickness of the shielding layer is about 82 μm. The shielding layer is a hollow structure. A bonding layer is provided between each shielding layer, and the bonding layer contains conductive particles. The glue film layer is made of polyester resin, and the thickness of the glue film layer is 3 μm.

[0046] When the electromagnetic shielding cover is laminated on the circuit board by conventional processes and tested by relevant resistance detection equipment, when the grounding area is 5 square millimeters, the grounding resistance of the electromagnetic shielding cover is less than 500 milliohms, having good shielding performance. At the same time, it has strong toughness and can fit well on the surface of electronic components on the circuit board.

[0047] Comparative Example 1

[0048] An electromagnetic shielding cover includes a shielding layer and a glue film layer stacked. The shielding layer only includes a conductive layer and does not have a flexible layer. The thickness of the conductive layer is 1.5 μm, the overall thickness of the shielding layer is 1.5 μm, and the thickness of the glue film layer is 3.5 μm.

[0049] When the electromagnetic shielding cover is laminated on the circuit board by conventional processes and tested by relevant resistance detection equipment, when the grounding area is 5 square millimeters, the grounding resistance of the electromagnetic shielding cover is close to 1000 milliohms. The electromagnetic shielding cover has weak toughness, the shielding layer breaks, and it cannot fit tightly on the surface of electronic components on the circuit board.

[0050] Another embodiment of the present utility model provides a circuit board, including a circuit board body and the electromagnetic shielding cover as described above; wherein, the electromagnetic shielding cover is laminated with the circuit board body.

[0051] Compared with the prior art, the beneficial effects of the embodiments of the present utility model are at least one of the following:

[0052] (1) The electromagnetic shielding cover is closely attached to the surface of the electronic component, greatly reducing the volume of the electronic device with the shielding cover, and thus promoting the development process of miniaturization and thinness of the electronic device;

[0053] (2) The structure of the electromagnetic shielding cover is improved, so that while the electromagnetic shielding cover has good shielding performance, it also has strong toughness and can be attached to the surface of the electronic component on the circuit board.

[0054] The above embodiments only represent several implementation manners of the present utility model, and the description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present utility model. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present utility model, several deformations and improvements can still be made, and these all belong to the protection scope of the present utility model. Therefore, the protection scope of the patent of the present utility model shall be subject to the appended claims.

Claims

1. An electromagnetic shielding cover, characterized in that: It comprises a shielding layer and a film layer; the shielding layer and the film layer are stacked, the shielding layer comprises a flexible layer and a conductive layer, the conductive layer is on the surface of the flexible layer, and the thickness of the conductive layer is 1 μm-8 μm.

2. The electromagnetic shielding cover according to claim 1, characterized in that: The shielding layer is a hollow structure.

3. The electromagnetic shielding cover according to claim 1, characterized in that: The thickness of a single shielding layer is 3 μm-50 μm.

4. The electromagnetic shielding cover according to claim 1, characterized in that: The adhesive film layer is made of insulating material or conductive adhesive.

5. The electromagnetic shielding cover according to claim 1, characterized in that: The thickness of the adhesive film layer is 2 μm-20 μm.

6. The electromagnetic shielding cover according to claim 1, characterized in that: The shielding layer is a one-layer or at least two-layer structure.

7. The electromagnetic shielding cover according to claim 6, characterized in that: When the shielding layer has at least two layers, a bonding layer is arranged between the shielding layers.

8. The electromagnetic shielding cover according to claim 7, characterized in that: The adhesive layer contains conductive particles.

9. The electromagnetic shielding cover according to claim 1, characterized in that: The surface of the shielding layer close to the adhesive film layer comprises a convex portion.

10. A circuit board, characterized in that: It comprises a circuit board body and an electromagnetic shielding cover as described in any one of claims 1 to 9; wherein the electromagnetic shielding cover is pressed together with the circuit board body.

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