Electromagnetic shield film

Abstract

The utility model discloses an electromagnetic shielding film, including metal foil layer, the opposite two sides of metal foil layer are equipped with first protective layer and second protective layer respectively, first protective layer is any one in nickel chromium alloy layer, nickel zinc alloy layer, chromium zinc alloy layer, second protective layer is any one in nickel chromium alloy layer, nickel zinc alloy layer, chromium zinc alloy layer, one side of second protective layer is equipped with insulating heat conducting layer away from metal foil layer. The electromagnetic shielding film of the utility model can reduce the thickness of electromagnetic shielding film and reduce the complexity of film structure, and has excellent thermal conductivity.

Description

Technical Field

[0001] This utility model belongs to the field of electromagnetic shielding film technology, and specifically relates to an electromagnetic shielding film. Background Technology

[0002] With the continuous iteration and upgrading of the electronic information industry, and the deepening evolution of cutting-edge technologies such as 5G / 6G communication and the Internet of Things, smart terminals are accelerating their development towards higher frequency, miniaturization, and higher integration. In the daily use scenarios of portable electronic devices such as mobile phones and tablets, their internal key components, such as CPUs and signal communication modules, not only radiate high-frequency electromagnetic waves, but also generate a lot of heat during the high-intensity processing and computation of the CPU and the high-power transmission of 5G signals.

[0003] Currently, the industry generally uses electromagnetic shielding films made of PET and other materials with added metal coatings to effectively address electromagnetic radiation issues. However, the complex structure of these films leads to complex manufacturing processes and high costs. Furthermore, the use of PET as the substrate results in poor thermal conductivity and a relatively thick overall thickness.

[0004] The information disclosed in this background section is intended only to enhance the understanding of the overall background of this utility model and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art. Utility Model Content

[0005] The purpose of this invention is to provide an electromagnetic shielding film that can reduce the thickness and complexity of the film structure, and has excellent thermal conductivity.

[0006] To achieve the above objectives, a specific embodiment of this utility model provides the following technical solution: an electromagnetic shielding film, comprising a metal foil layer, wherein a first protective layer and a second protective layer are respectively provided on the two opposite sides of the metal foil layer, wherein the first protective layer is any one of a nickel-chromium alloy layer, a nickel-zinc alloy layer, and a chromium-zinc alloy layer, and the second protective layer is any one of a nickel-chromium alloy layer, a nickel-zinc alloy layer, and a chromium-zinc alloy layer, wherein an insulating and heat-conducting layer is provided on the side of the second protective layer facing away from the metal foil layer.

[0007] In one or more embodiments of this utility model, the metal foil layer is any one of gold foil, silver foil, copper foil, and aluminum foil.

[0008] In one or more embodiments of this utility model, the thickness of the metal foil layer is 4 to 50 μm.

[0009] In one or more embodiments of this utility model, the thickness of the first protective layer is 5 to 200 nm.

[0010] In one or more embodiments of this utility model, the thickness of the second protective layer is 5 to 200 nm.

[0011] In one or more embodiments of this utility model, the insulating and thermally conductive layer includes an insulating layer and thermally conductive particles dispersed within the layer body.

[0012] In one or more embodiments of this utility model, the insulating layer is an acrylic resin layer.

[0013] In one or more embodiments of this utility model, the heat-conducting particles are at least one of aluminum oxide, aluminum nitride, boron nitride, and magnesium oxide.

[0014] In one or more embodiments of this utility model, the particle size of the thermally conductive particles is 1 to 3 μm.

[0015] In one or more embodiments of this utility model, the thickness of the insulating layer is 3 to 20 μm.

[0016] Compared with the prior art, the electromagnetic shielding film of this invention reduces the overall thickness of the electromagnetic shielding film by replacing the substrate and metal layer in the prior art with a metal foil layer. Combined with the first and second protective layers, it simplifies the overall structure of the electromagnetic shielding film. The insulating and thermally conductive layer provides insulation and heat conduction, avoiding short circuits caused by direct contact between the second protective layer and electronic equipment. Due to the low overall thickness of the film structure and the good thermal conductivity of each layer, the entire electromagnetic shielding film has excellent thermal conductivity. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of an electromagnetic shielding film in one example of this utility model.

[0019] Explanation of key figure labels: 1. Metal foil layer; 2. First protective layer; 3. Second protective layer; 4. Insulating and thermally conductive layer; 41. Insulating layer; 42. Thermally conductive particles. Detailed Implementation

[0020] To enable those skilled in the art to better understand the technical solutions in this disclosure, the technical solutions in the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this disclosure.

[0021] As described in the background section, existing electromagnetic shielding films generally use PET substrates, and then a metal layer is deposited on the PET substrate using a magnetron sputtering process. This metal layer can be a silver layer, a copper layer, an aluminum layer, a gold layer, etc. Considering both manufacturing costs and shielding effects, the metal layer is generally a silver layer. However, silver will oxidize after long-term use, leading to a deterioration in the shielding effect. Therefore, a protective layer (such as a metal oxide layer), such as a niobium pentoxide layer, needs to be magnetron sputtered on the silver layer. Oxygen needs to be introduced during the magnetron sputtering of the protective layer, which will cause the silver layer to oxidize directly. Therefore, a transition layer (to isolate oxygen) needs to be prepared on the silver layer before preparing the protective layer. In addition, the silver layer cannot be directly magnetron sputtered on the PET substrate. As a result, the existing electromagnetic shielding films have complex layer structures, cumbersome manufacturing processes, and high costs.

[0022] In addition, due to inherent defects in the magnetron sputtering process, the thickness of the metal layer is not uniform during its formation, and pits may appear in some areas of the metal layer, which affects the shielding effect.

[0023] Furthermore, technology is advancing rapidly, and consumers are pursuing smaller electronic devices. The existing electromagnetic shielding film uses a general PET substrate, which is about 100μm or more. In addition, the complex layer structure of the electromagnetic shielding film results in the existing electromagnetic shielding film being relatively thick and difficult to reduce.

[0024] Because existing technologies use PET as the substrate, which has poor thermal conductivity, the overall thermal conductivity of the electromagnetic shielding film is affected.

[0025] like Figure 1 As shown, the electromagnetic shielding film in one example of this utility model includes a metal foil layer 1. The two opposite sides of the metal foil layer 1 are respectively provided with a first protective layer 2 and a second protective layer 3. The first protective layer 2 is any one of a nickel-chromium alloy layer, a nickel-zinc alloy layer, and a chromium-zinc alloy layer. The second protective layer 3 is any one of a nickel-chromium alloy layer, a nickel-zinc alloy layer, and a chromium-zinc alloy layer. An insulating and thermally conductive layer 4 is provided on the side of the second protective layer 3 that is away from the metal foil layer 1.

[0026] It is understandable that the metal foil layer 1 not only serves to shield electromagnetic waves, but also acts as the substrate of the entire electromagnetic shielding film. Eliminating the PET substrate found in existing electromagnetic shielding films significantly reduces the overall thickness of the film, facilitating thinning. Furthermore, the electromagnetic shielding film in this example has only a three-layer structure, simplifying its structure and reducing the manufacturing steps, thus lowering its cost. The insulating and thermally conductive layer 4 provides both insulation and heat conduction. Since the metal foil layer 1, the first protective layer 2, and the second protective layer 3 can all be considered conductors, and the insulating and thermally conductive layer 4 itself is not conductive, it allows the insulating and thermally conductive layer 4 to contact other conductors or circuit surfaces within the electronic device. This prevents the second protective layer 3 from directly contacting other conductors or circuits inside the electronic device, thus avoiding short circuits and ensuring the safe operation of the equipment circuitry.

[0027] In addition, since the PET substrate has poor thermal conductivity, this example removes the PET substrate from the existing electromagnetic shielding film. The electromagnetic shielding film in this example has a lower thickness, and each layer in the electromagnetic shielding film has good thermal conductivity. Therefore, the entire electromagnetic shielding film has excellent thermal conductivity.

[0028] Furthermore, this example uses a metal foil layer 1 instead of the existing metal layer, which can fundamentally avoid the impact of metal layer defects caused by the electroplating process on the shielding effect.

[0029] The first protective layer 2 and the second protective layer 3 mainly serve to prevent water and oxygen from corroding the metal foil layer 1 and extend the service life of the metal foil layer 1.

[0030] Specifically, the metal foil layer 1 is any one of gold foil, silver foil, copper foil, and aluminum foil.

[0031] Specifically, the thickness of the metal foil layer 1 is 4–50 μm. It can be seen that the thickness of the metal foil layer 1 is much smaller than that of the PET substrate. To avoid over-design and increased material costs, the thickness of the metal foil layer 1 can be selected according to the shielding effect requirements. Electromagnetic waves have a deeper skin depth in the low-frequency band and a shallower skin depth in the high-frequency band. Once the thickness of the metal foil layer 1 reaches a multiple of its skin depth, further increasing the thickness has no significant effect on improving the shielding effect.

[0032] Specifically, the thickness of the first protective layer 2 is 5–200 nm. The thickness of the second protective layer 3 is 5–200 nm.

[0033] Specifically, the insulating and thermally conductive layer 4 includes an insulating layer 41 and thermally conductive particles 42 dispersed within the main body of the layer. The insulating layer 41 can be formed by coating with a coating liquid, which can be a commercially available acrylic resin coating liquid, such as Arakawa Chemical CHT-X1-NS. Its main function is insulation.

[0034] Specifically, the thermally conductive particles 42 are at least one of aluminum oxide, aluminum nitride, boron nitride, and magnesium oxide. It is understood that the more thermally conductive particles 42 there are, the better the thermal conductivity of the insulating thermally conductive layer 4. The optimal amount of thermally conductive particles 42 is generally around 40 wt% of the coating liquid. This balances thermal conductivity with the insulation and stability of the entire insulating thermally conductive layer 4.

[0035] Specifically, the particle size of the thermally conductive particles 42 is 1–3 μm. Specifically, the thickness of the insulating layer 41 is 3–20 μm.

[0036] The electromagnetic shielding film of this utility model will be described in detail below with reference to specific embodiments.

[0037] Example 1 The metal foil layer is a copper foil prepared by a rolling process, with a thickness of approximately 10 μm. The first protective layer is a nickel-chromium alloy plated on the surface of the copper foil using a magnetron sputtering process, with a thickness of approximately 50 nm. The second protective layer is also a nickel-chromium alloy plated on the surface of the copper foil using a magnetron sputtering process, with a thickness of approximately 50 nm. The insulating and thermally conductive layer is formed by adding boron nitride particles with a particle size of approximately 1–3 μm at a mass fraction of 40 wt% to an acrylic resin coating (Arakawa Chemical CHT-X1-NS), and applying it to the second protective layer using a doctor blade coating process, with a thickness of approximately 5 μm. After baking and curing at 80℃ / 60S and UV curing at 300 mJ / cm2, an insulating and thermally conductive layer with thermally conductive particle channels is formed, resulting in an electromagnetic shielding film.

[0038] Comparative Example 1 Except for the insulating and thermally conductive layer, which uses pure acrylate-based resin (Arakawa Chemical CHT-X1-NS) without adding particles, the materials and methods for the other layers are the same as in Example 1.

[0039] The electromagnetic shielding films of Example 1 and Comparative Example 1 were tested for thermal conductivity and average shielding effectiveness in the 0.1MHz-1000MHz frequency band. The specific test standards are as follows, and the data are shown in the table below.

[0040] Thermal conductivity: Measured in accordance with the national standard GB / T 3651-2008 "Method for Measurement of Thermal Conductivity of Metals at High Temperature".

[0041] Electromagnetic wave shielding effectiveness: Measured in accordance with the national standard GB / T30142-2013 "Measurement Method for Shielding Effectiveness of Planar Electromagnetic Shielding Materials".

[0042] As can be seen from the shielding effectiveness test data in Example 1, the electromagnetic shielding film of this invention has a good shielding effect.

[0043] The thermal conductivity data from Example 1 and Comparative Example 1 show that the electromagnetic shielding film of this invention has good thermal conductivity.

[0044] In summary, the electromagnetic shielding film of this invention has the advantages of good thermal conductivity, good shielding effect, simple film structure, low manufacturing cost, and thin thickness.

[0045] It will be apparent to those skilled in the art that this disclosure is not limited to the details of the exemplary embodiments described above, and that this disclosure can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of this disclosure is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this disclosure. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0046] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An electromagnetic shielding film, characterized in that, The device includes a metal foil layer, and a first protective layer and a second protective layer are respectively provided on the two opposite sides of the metal foil layer. The first protective layer is any one of a nickel-chromium alloy layer, a nickel-zinc alloy layer, and a chromium-zinc alloy layer. The second protective layer is any one of a nickel-chromium alloy layer, a nickel-zinc alloy layer, and a chromium-zinc alloy layer. An insulating and heat-conducting layer is provided on the side of the second protective layer that is away from the metal foil layer.

2. The electromagnetic shielding film according to claim 1, characterized in that, The metal foil layer can be any one of gold foil, silver foil, copper foil, or aluminum foil.

3. The electromagnetic shielding film according to claim 1, characterized in that, The thickness of the metal foil layer is 4~50μm.

4. The electromagnetic shielding film according to claim 1, characterized in that, The thickness of the first protective layer is 5~200nm.

5. The electromagnetic shielding film according to claim 1, characterized in that, The thickness of the second protective layer is 5~200nm.

6. The electromagnetic shielding film according to claim 1, characterized in that, The insulating and thermally conductive layer includes an insulating layer and thermally conductive particles dispersed within the main body of the layer.

7. The electromagnetic shielding film according to claim 6, characterized in that, The insulating layer is an acrylic resin layer.

8. The electromagnetic shielding film according to claim 6, characterized in that, The heat-conducting particles are at least one of aluminum oxide, aluminum nitride, boron nitride, and magnesium oxide.

9. The electromagnetic shielding film according to claim 6, characterized in that, The particle size of the thermally conductive particles is 1~3μm.

10. The electromagnetic shielding film according to claim 6, characterized in that, The thickness of the insulating layer is 3~20μm.

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