An electromagnetic shielding cover and circuit board

Abstract

This invention relates to the field of electronic communication materials technology, and in particular to an electromagnetic shielding cover and circuit board. The invention discloses an electromagnetic shielding cover and circuit board. The electromagnetic shielding cover includes a protective layer, a shielding layer, and an adhesive film layer stacked sequentially. Deformable filler particles are disposed in the protective layer. These particles undergo sublimation, liquefaction, or melting after high-temperature pressing. The shielding layer includes a conductive-coated non-metallic layered material and a conductive adhesive layer. By incorporating deformable filler particles in the protective layer, when the electromagnetic shielding cover is pressed onto the circuit board, the particles undergo sublimation, liquefaction, or melting under high temperature and pressure, causing the shielding cover to soften overall after pressing. This improves the deformation efficiency of the protective layer, allowing it to penetrate into the gaps between components, forming an adherent wrapping. This enhances the overall tensile strength of the electromagnetic shielding cover, preventing breakage and thus isolating components, avoiding electromagnetic interference between adjacent components, and achieving a good shielding effect.

Description

Technical Field

[0001] This invention relates to the field of electronic communication materials technology, and in particular to an electromagnetic shielding cover and circuit board. Background Technology

[0002] An electromagnetic shield is a metal enclosure used for electromagnetic shielding, primarily to reduce the effects of electromagnetic interference (EMI) and electromagnetic radiation (EMR). Its main function is to block or suppress electromagnetic waves within a specific spatial range to achieve the purposes of shielding against interference, protecting electronic equipment, and ensuring secure communications.

[0003] The principle of electromagnetic shielding is mainly based on electromagnetic field theory and the electrical conductivity of metallic materials. Electromagnetic fields are generated by electric charges and currents. Metallic materials contain a large number of free electrons, which can generate current under the influence of electromagnetic fields, thus counteracting the effects of external electromagnetic fields on the internal circuits and components of the equipment. At the same time, the electrical conductivity of metallic materials also gives them good electromagnetic shielding effects, effectively absorbing and reflecting electromagnetic waves.

[0004] Existing electromagnetic shielding covers are metal shell structures that enclose all components mounted on the circuit board to achieve electromagnetic shielding. However, metal shell electromagnetic shielding covers are heavy, bulky, and cannot be bent, thus failing to meet the requirements of the trend towards thinner and lighter mobile terminals or other electronic devices. To address this issue, those skilled in the art have developed flexible electromagnetic shielding covers. However, the circuit boards with mounted electronic components have higher tolerances and smaller gaps between components, making it impossible for the electromagnetic shielding cover to extend between them, resulting in poor shielding effectiveness. Therefore, while thinning the flexible electromagnetic shielding cover allows it to be pressed together to extend between components, it is prone to breakage, further degrading the shielding effect. Summary of the Invention

[0005] To address the aforementioned problems, this invention develops an electromagnetic shielding cover that can extend into the gaps between components, forming a close-fitting enclosure without breakage, thus achieving a good shielding effect.

[0006] The purpose of this invention is to provide an electromagnetic shielding cover and circuit board that can achieve a good shielding effect.

[0007] To achieve the above objectives, a first aspect of the present invention provides an electromagnetic shielding cover, comprising at least a protective layer, a shielding layer, and an adhesive film layer stacked sequentially; the protective layer contains deformable filler particles, which undergo at least one of sublimation or melting after being pressed at high temperature;

[0008] The shielding layer comprises a conductive non-metallic layered material and a conductive adhesive layer.

[0009] In one embodiment, the maximum width of the deformable filler particles is 5~10 μm.

[0010] In one embodiment, the number of deformable filler particles per unit volume is 3 to 40.

[0011] In one embodiment, the proportion of deformable filler particles with a maximum width of 5-8 μm per unit volume is 40%-80%.

[0012] In one embodiment, the thickness of the protective layer is 12~55μm.

[0013] In one embodiment, the vertical height H1 of the position of the deformable filler particle away from the shielding layer from the surface of the protective layer away from the shielding layer satisfies the following condition with respect to the thickness H of the protective layer: 1 / 5 ≤ H1 / H ≤ 3 / 4;

[0014] And / or, the vertical height H2 of the position of the deformable filler particle near the shielding layer from the surface of the protective layer near the shielding layer satisfies the following condition with respect to the thickness H of the protective layer: 1 / 5 ≤ H2 / H.

[0015] In one embodiment, the conductive coated non-metallic layered material includes a non-metallic support layer and a metallic encapsulation layer, wherein the metallic encapsulation layer is wrapped around the non-metallic support layer.

[0016] In one embodiment, the non-metallic support layer is provided with pores, the porosity of which is 30% to 60%.

[0017] In one embodiment, the deformable filler particles include at least one of high-melting-point paraffin wax, polyethylene wax, silicone wax, glyceryl stearate, p-dichlorobenzene, and anthracene.

[0018] In one embodiment, the shielding layer comprises the conductive coated non-metallic layered material, the conductive adhesive, and the conductive coated non-metallic layered material stacked sequentially.

[0019] In one embodiment, the shielding layer includes the conductive-coated non-metallic layered material and the solid shielding layer, with a conductive adhesive layer disposed between the conductive-coated non-metallic layered material and the solid shielding layer.

[0020] To achieve the above objectives, in a second aspect, the present invention also provides a circuit board, the circuit board including the electromagnetic shielding cover described in any of the above embodiments.

[0021] Compared with the prior art, the beneficial effects of the embodiments of the present invention are as follows: The electromagnetic shielding cover includes a protective layer, a shielding layer and an adhesive film layer stacked in sequence. Deformable filler particles are provided in the protective layer. When the electromagnetic shielding cover is pressed onto the circuit board, the deformable filler particles sublimate or melt under high temperature and high pressure conditions, making the shielding cover soften as a whole after pressing, improving the deformation efficiency of the protective layer, and enabling it to penetrate into the gaps between components to form an attached wrap, thereby improving the overall breaking resistance of the electromagnetic shielding cover, preventing breakage, thus isolating components, avoiding electromagnetic interference between adjacent components, and achieving a good shielding effect.

[0022] On the other hand, by limiting the distribution of deformable filler particles in the protective layer, the volatile substances can be smoothly discharged from the protective layer after the deformable filler particles are compressed, without causing defects on the surface or inside of the protective layer, thereby improving the quality of the electromagnetic shield.

[0023] Furthermore, the shielding layer adopts at least two of the following: a solid shielding layer, a conductive adhesive layer, and a conductive-coated non-metallic layered material. This is beneficial for improving the shielding performance and mechanical properties of the electromagnetic shielding cover, facilitating subsequent processing and use, and ensuring the reliability of the electromagnetic shielding quality. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the first electromagnetic shielding cover provided in the embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of the structure of the second electromagnetic shielding cover provided in the embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of the structure of the third type of electromagnetic shielding cover provided in the embodiments of the present invention;

[0027] Figure 4 This is a schematic diagram of the structure of the fourth electromagnetic shielding cover provided in the embodiments of the present invention;

[0028] Figure 5 This is a schematic diagram of the structure of the fifth electromagnetic shielding cover provided in the embodiments of the present invention.

[0029] Among them, 1. Protective layer; 2. Shielding layer; 3. Adhesive film layer; 4. Deformation filler particles; 21. Solid shielding layer; 22. Conductive adhesive layer; 23. Conductive coated non-metallic layered material. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] In the description of the specification and claims, it should be understood that the terms "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the present invention, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the embodiments of the present invention.

[0032] Furthermore, the terms "first," "second," etc., used in the specification and claims are used only to distinguish the description of the same technical features and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated, nor necessarily the order of description or chronological sequence. Where appropriate, the terms are interchangeable. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature.

[0033] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of an electromagnetic shielding cover according to an embodiment of the present invention. The present invention provides an electromagnetic shielding cover comprising at least a protective layer 1, a shielding layer 2, and a film layer 3 stacked sequentially; the protective layer 1 contains deformable filler particles 4, which undergo at least one of sublimation or melting after high-temperature pressing;

[0034] The shielding layer 2 includes a conductive non-metallic layered material 23 and a conductive adhesive layer 22.

[0035] It is worth noting that in practical applications, such as in the field of circuit boards, the adhesive film layer 3 of the electromagnetic shielding cover is bonded to the substrate of the circuit board at high temperature.

[0036] In this embodiment of the invention, the protective layer 1 serves to protect the shielding layer 2. The thickness of the protective layer 1 is 12-55 μm. The protective layer 1 comprises at least one of polyurethane, polyester, alkyd resin, epoxy resin, acrylic resin, polyimide, polystyrene, polyvinyl acetate, polyethylene, polypropylene, polyamide, rubber, phenolic resin, urethane resin, and alkyd resin, which makes the protective layer 1 more flexible. Preferably, the thickness of the protective layer 1 is 15-25 μm.

[0037] It should be noted that when the electromagnetic shielding cover is relatively thin, a carrier layer can be set on the surface of the protective layer 1 away from the shielding layer 2. This makes the electromagnetic shielding cover less prone to wrinkling or breakage during processing and application. After the electromagnetic shielding cover is pressed against the circuit board substrate, the carrier layer is removed. Therefore, a release agent is provided on the side of the carrier layer closest to the protective layer 1. The thickness of the carrier layer is 38~50μm. By limiting the thickness of the carrier layer to 38~100μm, the thickness of the carrier layer is within a suitable range. It is not too thin to provide support, nor too thick to make it difficult to press the electromagnetic shielding cover into the gaps between components, thus affecting the shielding effect.

[0038] In this embodiment of the invention, deformable filler particles 4 are provided in the protective layer 1. When the electromagnetic shielding cover is pressed onto the circuit board, the deformable filler particles 4 sublimate or melt under high temperature and high pressure conditions, which reduces the elasticity of the shielding cover after pressing and makes it softer overall. This is beneficial to improve the deformation efficiency of the protective layer, allowing it to extend into the gaps between components and form an attached wrapping, thereby improving the overall breaking resistance of the electromagnetic shielding cover. It does not break at the points where components protrude from the circuit board and extends into the spaces between adjacent components to form a shield, thereby isolating the components and avoiding electromagnetic interference between adjacent components, achieving a good shielding effect.

[0039] Preferably, the deformable filler particles 4 include at least one of high-melting-point paraffin wax, polyethylene wax, silicone wax, glyceryl stearate, p-dichlorobenzene, and anthracene.

[0040] Furthermore, in this embodiment of the invention, the vertical height H1 of the position of the deformable filler particle 4 away from the surface of the protective layer 1 away from the shielding layer 2 is satisfied by the thickness H of the protective layer 1: 1 / 5 ≤ H1 / H ≤ 3 / 4. By limiting the distribution of the deformable filler particle 4 in the protective layer 1, the deformation rate will not be too fast due to the deformable filler particle 4 being too close to the surface of the protective layer 1 away from the shielding layer 2, thus causing a large number of pits and damage defects on the surface of the protective layer 1, affecting the appearance quality of the electromagnetic shielding cover; nor will the volatile substances not be easily discharged from the protective layer 1 during deformation due to the deformable filler particle 4 being too far away from the surface of the protective layer 1 away from the shielding layer 2, thus causing bubbles and delamination defects inside the protective layer 1, affecting the quality of the electromagnetic shielding cover. Therefore, the vertical height H1 of the position of the deformable filler particle 4 away from the shielding layer 2 and the thickness H of the protective layer 1 is limited to the range of 1 / 5 ≤ H1 / H ≤ 3 / 4. This ensures that when the deformable filler particle 4 deforms, volatile substances can be smoothly discharged from the protective layer 1 without causing defects on the surface or inside of the protective layer 1, thereby improving the quality of the electromagnetic shield. Optionally, the ratio of H1 / H can be any value or a range of any two values ​​among 1 / 5, 2 / 5, 3 / 5, 1 / 4, 2 / 4 and 3 / 4.

[0041] Furthermore, in this embodiment of the invention, the vertical height H2 of the deformable filler particle 4 near the shielding layer 2 from the surface of the protective layer 1 near the shielding layer 2 satisfies the following condition with respect to the thickness H of the protective layer 1: 1 / 5 ≤ H2 / H. By limiting the distribution of the deformable filler particle 4 in the protective layer 1, the shielding layer 2 will not be damaged during deformation due to the deformable filler particle 4 being too close to the shielding layer 1, thus affecting the shielding effect of the electromagnetic shielding cover. Preferably, the H2 / H ratio is 2 / 5, 3 / 5, 1 / 4, or 2 / 4.

[0042] It should be noted that the maximum width of the deformable filler particles 4 in the protective layer 1 of the electromagnetic shielding cover is 5~10μm. By limiting the size of the deformable filler particles 4, it is possible to prevent the particles from being too large, which would cause defects inside the protective layer 1, or too small, which would prevent them from failing to soften during deformation and thus affecting the shielding cover's ability to encapsulate the device, resulting in a negligible improvement in shielding effectiveness. Therefore, limiting the maximum width of the deformable filler particles 4 to the range of 5~10μm is beneficial for achieving compression softening, allowing the electromagnetic shielding cover to be pressed into the gaps between the devices, resulting in excellent encapsulation, thereby isolating the components, avoiding electromagnetic interference between adjacent components, and achieving a good shielding effect. Optionally, the size of the deformable filler particles 4 can be any value or a range of any two values ​​from 5, 6, 6.6, 7, 8, and 10μm.

[0043] Furthermore, the number of deformable filler particles 4 per unit volume is 3 to 40. By limiting the distribution of the deformable filler particles 4, the number of deformable filler particles 4 per unit volume is kept within a suitable range. Too few particles would result in insufficient softening during deformation, thus affecting the electromagnetic shielding cover's encapsulation of the device and leading to a negligible improvement in shielding effectiveness. Conversely, too many particles would cause defects within the protective layer 1. Therefore, limiting the number of deformable filler particles 4 per unit volume to 3 to 40 facilitates softening after pressing, allowing the electromagnetic shielding cover to be pressed into the gaps of the device, resulting in excellent encapsulation and isolation of the components, preventing electromagnetic interference between adjacent components, and ultimately achieving a good shielding effect. Preferably, the number of deformable filler particles 4 per unit volume is 15 to 30.

[0044] Preferably, the proportion of deformable filler particles 4 with a maximum width of 5~8μm per unit volume is 40%~80%. In this way, while further ensuring protection and support, the overall elasticity of the shielding cover is reduced after compression.

[0045] In this embodiment of the invention, a shielding layer 2 is disposed between the protective layer 1 and the adhesive film layer 3. The shielding layer 2 serves as the core material for shielding. Through mechanisms such as reflection, absorption, and guidance, the physical properties of the shielding body are used to limit the propagation of electromagnetic waves, thereby reducing electromagnetic interference. It can prevent external interference sources from affecting the device signals, and it can also prevent interference signals generated by the device from affecting the normal operation of other components.

[0046] It is worth noting that the shielding layer 2 includes a conductive-coated non-metallic layered material 23 and a conductive adhesive 22, with the conductive adhesive 22 close to the protective layer 1 (e.g., Figure 1 ), or a conductive, non-metallic layered material 23 near the protective layer 1 (such as Figure 2 ).

[0047] It should be noted that the conductive coated non-metallic layered material 23 includes a non-metallic support layer and a metallic encapsulation layer, with the metallic encapsulation layer covering the non-metallic support layer. Preferably, the non-metallic support layer is made of cloth, fiber, or film, making the shielding layer 2 relatively soft, with high mechanical strength and not easily broken. During press-fitting, the electromagnetic shielding cover can smoothly fill the gaps between components. Meanwhile, the metallic encapsulation layer is made of at least one material selected from aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver, gold, graphene, and conductive polymers, which can meet the requirements of ultra-high shielding efficiency, thereby effectively isolating components, avoiding electromagnetic interference between adjacent components, and achieving excellent shielding effect.

[0048] It should be noted that the conductive adhesive layer 22 is made by adding appropriate conductive particles to the adhesive film layer, which makes the electromagnetic shielding cover more flexible and easy to fill into the gaps between components during pressing, thus achieving a good shielding effect.

[0049] In this embodiment of the invention, the shielding layer 2 includes a conductive adhesive layer 22 and a conductive coated non-metallic layered material 23. This structure, being a two-layer composite structure, provides excellent shielding performance. Furthermore, the use of the conductive coated non-metallic layered material 23 as the shielding material, with its support layer being cloth, fiber, or film, and the conductive adhesive layer being relatively soft, makes the shielding layer 2 relatively flexible, with high mechanical strength and resistance to breakage. During press-fitting, the electromagnetic shielding cover can smoothly fill the gaps between components, thereby effectively isolating the components and preventing electromagnetic interference between adjacent components, achieving excellent shielding performance.

[0050] Furthermore, the non-metallic support layer is provided with pores, and the porosity of the pores is between 30% and 60%. By providing pores in the non-metallic support layer, the flexibility of the electromagnetic shielding cover can be improved. Limiting the porosity of the pores to a suitable range prevents the following: on the one hand, too many pores would result in a low amount of metal layer wrapped on the non-metallic support layer, which, while improving the flexibility of the electromagnetic shielding cover, would not achieve the desired shielding effect due to low shielding material content; on the other hand, too few pores would prevent the improvement in flexibility of the electromagnetic shielding cover from being insignificant, failing to achieve the desired softening effect, and thus affecting the shielding cover's encapsulation of the device, resulting in a negligible improvement in shielding effect. Therefore, limiting the porosity of the pores to 30% to 60% improves the flexibility of the electromagnetic shielding cover while ensuring a sufficient amount of metal layer encapsulation in the non-metallic support layer. This allows the electromagnetic shielding cover to be pressed into the gaps between the devices, resulting in excellent encapsulation, thereby isolating the components, preventing electromagnetic interference between adjacent components, and ultimately achieving a good shielding effect.

[0051] See Figure 3 , Figure 3 This is another electromagnetic shielding cover provided in the embodiment of the present invention. The shielding layer 2 includes the conductive coated non-metallic layered material 23, the conductive adhesive layer 22 and the conductive coated non-metallic layered material 23 stacked in sequence.

[0052] In this embodiment of the invention, the shielding layer 2 is composed of two layers of conductive-coated non-metallic layered material 23 connected in the middle by a conductive adhesive layer 21. This structure, being a three-layer composite structure, provides superior shielding performance. Furthermore, the use of conductive-coated non-metallic layered material 23 as the shielding material, with its support layer being cloth, fiber, or film, and the conductive adhesive layer being relatively soft, makes the shielding layer 2 flexible, with high mechanical strength and resistance to breakage. During press-fitting, the electromagnetic shielding cover can smoothly fill the gaps between components, effectively isolating them and preventing electromagnetic interference between adjacent components, achieving excellent shielding performance. Moreover, the three layers of shielding material exhibit excellent conductivity, better meeting the application requirements for shielding.

[0053] See Figure 4 , Figure 4 This is another electromagnetic shielding cover provided in the embodiment of the present invention. The shielding layer 2 includes the conductive coated non-metallic layered material 23 and the solid shielding layer 21. A conductive adhesive layer 22 is disposed between the conductive coated non-metallic layered material 23 and the solid shielding layer 21.

[0054] In this embodiment of the invention, the shielding layer 2 uses a solid shielding layer 21, a conductive adhesive layer 22, and a conductive coated non-metallic layered material 23 as shielding materials. Since the supporting layer of the conductive coated non-metallic layered material 23 is cloth, fiber, or film, and the conductive adhesive layer is relatively soft, the shielding layer 2 is relatively soft and has high mechanical strength, making it not easy to break. When pressed and used, the electromagnetic shielding cover can smoothly fill the gaps between components, achieving excellent shielding effect. At the same time, combined with the solid shielding layer 21, the shielding effect is even better, and the three shielding materials have excellent conductivity, better meeting the shielding application requirements.

[0055] Preferably, the solid shielding layer 21 is made of at least one material selected from aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver, gold, graphene, and conductive polymer, which can meet the requirements of ultra-high shielding effectiveness.

[0056] It should be noted that the shielding layer 2 can be a conductive, non-metallic layered material 23, a conductive adhesive layer 22, and the solid shielding layer 21 stacked sequentially, with the conductive, non-metallic layered material 23 close to the protective layer 1 (e.g., Figure 4 The shielding layer 2 can also be a solid shielding layer 21, a conductive adhesive layer 22, and a conductive coated non-metallic layered material 23 stacked sequentially, wherein the conductive coated non-metallic layered material 23 is located away from the protective layer 1 (e.g., Figure 5 ).

[0057] Preferably, the adhesive in the conductive adhesive layer 22 is made of at least one material selected from pressure-sensitive adhesive and thermosetting adhesive.

[0058] Furthermore, in this embodiment of the invention, the adhesive film layer 3 serves both as an adhesive and a conductor. In practical applications, such as in the field of circuit boards, the electromagnetic shielding cover's adhesive film layer 3 is bonded to the circuit board substrate under high temperature pressure. Simultaneously, interference signals generated by devices are guided to the circuit board's ground plane through the shielding layer and the adhesive film layer, achieving shielding. The adhesive film layer 3 may contain conductive particles for grounding; when the shielding layer 2 has a protrusion near the adhesive film layer 3, it can pierce the adhesive film layer 3 to achieve grounding. Alternatively, the adhesive film layer 3 may not contain conductive particles.

[0059] It is worth noting that the adhesive film layer 3 is made of at least one material selected from pressure-sensitive adhesive and thermosetting adhesive. Preferably, pressure-sensitive adhesive is selected so that when the electromagnetic shielding cover fails, it can be removed and replaced, enabling easy rework and meeting maintenance needs.

[0060] Embodiments of the present invention also provide a circuit board, which includes an electromagnetic shielding cover according to any embodiment of the present invention.

[0061] The electromagnetic shielding cover and circuit board provided in this embodiment of the invention have the following advantages:

[0062] On one hand, the electromagnetic shielding cover includes a protective layer, a shielding layer, and an adhesive film layer stacked in sequence. Deformable filler particles are placed in the protective layer. When the electromagnetic shielding cover is pressed onto the circuit board, the deformable filler particles sublimate or melt under high temperature and high pressure conditions, making the shielding cover soften as a whole after pressing. This improves the deformation efficiency of the protective layer, allowing it to penetrate into the gaps between components and form an adhered wrapping. This improves the overall breaking resistance of the electromagnetic shielding cover, preventing breakage and thus isolating components and avoiding electromagnetic interference between adjacent components, achieving a good shielding effect.

[0063] On the other hand, by limiting the distribution of deformable filler particles in the protective layer, the volatile substances can be smoothly discharged from the protective layer after the deformable filler particles are compressed, without causing defects on the surface or inside of the protective layer, thereby improving the quality of the electromagnetic shield.

[0064] Furthermore, the shielding layer adopts at least two of the following: a solid shielding layer, a conductive adhesive layer, and a conductive-coated non-metallic layered material. This is beneficial for improving the shielding performance and mechanical properties of the electromagnetic shielding cover, facilitating subsequent processing and use, and ensuring the reliability of the electromagnetic shielding quality.

[0065] To demonstrate the beneficial effects of the electromagnetic shielding cover and circuit board provided in the embodiments of the present invention, the following description is provided in conjunction with several embodiments and comparative examples.

[0066] Example 1:

[0067] An electromagnetic shielding cover includes a protective layer 1, a shielding layer 2, and an adhesive film layer 3 stacked sequentially. Deformable filler particles 4 are disposed in the protective layer 1. The maximum width of the deformable filler particles 4 is 5~6μm, and the number of deformable filler particles 4 per unit volume is 30~40. The thickness of the protective layer 1 is 20μm. The shielding layer 2 is a conductive non-metallic layered material 23 and a conductive adhesive 22 stacked sequentially, with the conductive non-metallic layered material 23 close to the protective layer 1.

[0068] Example 2:

[0069] The electromagnetic shielding cover in this embodiment is the same as that in embodiment 1, except that the maximum width of the deformable filler particles 4 is 7~8μm.

[0070] Example 3:

[0071] The electromagnetic shielding cover in this embodiment is the same as that in Embodiment 1, except that the maximum width of the deformable filler particles 4 is 9~10μm.

[0072] Example 4:

[0073] The electromagnetic shielding cover in this embodiment is the same as that in embodiment 1, except that the number of deformable filler particles 4 per unit volume is 10 to 20.

[0074] Example 5:

[0075] The electromagnetic shielding cover in this embodiment is the same as that in embodiment 1, except that the number of deformable filler particles 4 per unit volume is 3 to 10.

[0076] Example 6:

[0077] The electromagnetic shielding cover in this embodiment is the same as that in embodiment 1, except that the shielding layer 2 includes the conductive coated non-metallic layered material 23, the conductive adhesive layer 22 and the conductive coated non-metallic layered material 23 stacked in sequence.

[0078] Example 7:

[0079] The electromagnetic shielding cover in this embodiment is the same as that in embodiment 1, except that: the shielding layer 2 includes the conductive coated non-metallic layered material 23 and the solid shielding layer 21, and a conductive adhesive layer 22 is disposed between the conductive coated non-metallic layered material 23 and the solid shielding layer 21.

[0080] Comparative Example 1:

[0081] The electromagnetic shielding cover of this embodiment includes a protective layer 1, a shielding layer 2 and an adhesive film layer 3 stacked sequentially. The protective layer 1 contains no deformable filler particles. The thickness of the protective layer 1 is 20 μm. The shielding layer 2 consists of a conductive non-metallic layered material 23 and a conductive adhesive 22 stacked sequentially. The conductive non-metallic layered material 23 is close to the protective layer 1.

[0082] Comparative Example 2:

[0083] The electromagnetic shielding cover in this embodiment is the same as that in Embodiment 1, except that the maximum width of the deformable filler particles 4 is 2~3μm.

[0084] Comparative Example 3:

[0085] The electromagnetic shielding cover in this embodiment is the same as that in Embodiment 1, except that the maximum width of the deformable filler particles 4 is 20~30μm.

[0086] Comparative Example 4:

[0087] The electromagnetic shielding cover in this embodiment is the same as that in embodiment 1, except that the number of deformable filler particles 4 per unit volume is 1 to 2.

[0088] Comparative Example 5:

[0089] The electromagnetic shielding cover in this embodiment is the same as that in embodiment 1, except that the number of deformable filler particles 4 per unit volume is 60 to 80.

[0090] Performance testing:

[0091] Electromagnetic shielding cover shielding effect test

[0092] The shielding effectiveness of the electromagnetic shielding covers in Examples 1-7 and Comparative Examples 1-5 was tested.

[0093] S1: Place the interference source device and the interfered device in the test environment according to the actual use scenario, keeping a certain distance, such as 2~4mm. Turn on the interference source and the interfered device, and use a spectrum analyzer to measure the strength of the interference signal received by the interfered device, which is recorded as P1.

[0094] S2: Cover the interference source device with the electromagnetic shielding cover of the present invention, and measure the strength of the interference signal received by the disturbed device again, which is recorded as P2.

[0095] S3: Calculate and evaluate the shielding effectiveness. The test results are shown in Table 1.

[0096] Table 1. Shielding effectiveness test of electromagnetic shielding covers in Examples 1-7 and Comparative Examples 1-5

[0097] condition Maximum width of deformable filler particles / μm Number of deformable filler particles / individual Shielding effect / dB Example 1 5~6 30~40 68 Example 2 7~8 30~40 70 Example 3 9~10 30~40 75 Example 4 5~6 10~20 66 Example 5 5~6 3~10 63 Example 6 5~6 30~40 85 Example 7 5~6 30~40 83 Comparative Example 1 / / 44 Comparative Example 2 2~3 30~40 47 Comparative Example 3 20~30 30~40 53 Comparative Example 4 5~6 1~2 45 Comparative Example 5 5~6 60~80 52

[0098] As shown in Table 1, by applying the electromagnetic shielding cover described in this embodiment, when the electromagnetic shielding cover is pressed onto the circuit board, the deformation filler particles deform under high temperature and high pressure conditions, and volatile substances are discharged from the protective layer, making the shielding cover softer overall after pressing, improving the deformation efficiency of the protective layer, and enabling it to extend into the gaps between components to form an attached wrap, thereby improving the overall breaking resistance of the electromagnetic shielding cover, preventing breakage, thus isolating components, avoiding electromagnetic interference between adjacent components, and achieving a good shielding effect.

[0099] Examples 1-3 are basically the same, the main difference being the difference in the maximum width of the deformable filler particles 4. As shown in the test results in Table 1, as the maximum width of the deformable filler particles 4 gradually increases, the shielding effectiveness becomes higher and higher. This indicates that after the deformable filler particles 4 are compressed and deformed, the electromagnetic shielding cover becomes more flexible, which can attach and wrap the device, thereby improving the overall breaking resistance of the electromagnetic shielding cover, preventing breakage, thus isolating the components, avoiding electromagnetic interference between adjacent components, and achieving a good shielding effect.

[0100] Examples 1 and 4-5 are basically the same, the main difference being the difference in the number of deformable filler particles 4 per unit volume. As shown in the test results in Table 1, as the number of deformable filler particles 4 decreases, the shielding effect deteriorates, indicating that if there are too few deformable filler particles 4, the softening effect of the electromagnetic shielding cover is not significant, and thus the contribution to the shielding effect is not significant.

[0101] Examples 1 and 6-7 are basically the same, the main difference being the structure of shielding layer 2. As shown in Table 1, the combined use of three shielding layers significantly improves the shielding effect.

[0102] In summary, the electromagnetic shielding cover comprises a protective layer, a shielding layer, and an adhesive film layer stacked sequentially. By incorporating deformable filler particles in the protective layer, these particles deform under high temperature and pressure conditions when the electromagnetic shielding cover is pressed onto the circuit board. This causes the shielding cover to soften as a whole after pressing, improving the deformation efficiency of the protective layer. The filler particles can then penetrate into the gaps between components, forming an adherent wrapping, thereby enhancing the overall tensile strength of the electromagnetic shielding cover, preventing breakage, and achieving a good shielding effect.

[0103] On the other hand, by limiting the distribution of deformable filler particles in the protective layer, the volatile substances can be smoothly discharged from the protective layer after the deformable filler particles are deformed, without causing defects on the surface or inside of the protective layer, thereby improving the quality of the electromagnetic shield.

[0104] Furthermore, the shielding layer adopts at least two of the following: a solid shielding layer, a conductive adhesive layer, and a conductive-coated non-metallic layered material. This is beneficial for improving the shielding performance and mechanical properties of the electromagnetic shielding cover, facilitating subsequent processing and use, and ensuring the reliability of the electromagnetic shielding quality.

[0105] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0106] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. An electromagnetic shielding cover, characterized in that, It includes at least a protective layer, a shielding layer, and an adhesive film layer stacked sequentially; the protective layer contains deformable filler particles, which undergo at least one of sublimation or melting after high-temperature pressing; The shielding layer comprises a conductive non-metallic layered material and a conductive adhesive layer.

2. The electromagnetic shielding cover as described in claim 1, characterized in that, The maximum width of the deformable filler particles is 5~10μm.

3. The electromagnetic shielding cover as described in claim 1, characterized in that, The thickness of the protective layer is 12~55μm.

4. The electromagnetic shielding cover as described in claim 1, characterized in that, The vertical height H1 of the position of the deformable filler particle away from the shielding layer from the surface of the protective layer away from the shielding layer satisfies the following condition with respect to the thickness H of the protective layer: 1 / 5 ≤ H1 / H ≤ 3 / 4; And / or, the vertical height H2 of the position of the deformable filler particle near the shielding layer from the surface of the protective layer near the shielding layer satisfies the following condition with respect to the thickness H of the protective layer: 1 / 5 ≤ H2 / H.

5. The electromagnetic shielding cover as described in claim 1, characterized in that, The conductive coated non-metallic layered material includes a non-metallic support layer and a metallic encapsulation layer, with the metallic encapsulation layer covering the non-metallic support layer.

6. The electromagnetic shielding cover as described in claim 5, characterized in that, The non-metallic support layer is provided with pores, and the porosity of the pores is 30% to 60%.

7. The electromagnetic shielding cover as described in claim 1, characterized in that, The deformable filler particles include at least one of high-melting-point paraffin wax, polyethylene wax, silicone wax, glyceryl stearate, p-dichlorobenzene, and anthracene.

8. The electromagnetic shielding cover as described in any one of claims 1-7, characterized in that, The shielding layer comprises, in sequence, the conductive coated non-metallic layered material, the conductive adhesive, and the conductive coated non-metallic layered material.

9. The electromagnetic shielding cover as described in any one of claims 1-7, characterized in that, The shielding layer includes the conductive-coated non-metallic layered material and the solid shielding layer, with a conductive adhesive layer disposed between the conductive-coated non-metallic layered material and the solid shielding layer.

10. A circuit board, characterized in that, The circuit board includes the electromagnetic shielding cover as described in any one of claims 1-9.

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