Shielding film and circuit board

Abstract

The application discloses a shielding film and a circuit board, wherein the shielding film comprises a first film layer, a contrast structure layer and an electromagnetic shielding layer; the first film layer is arranged on the first side of the electromagnetic shielding layer; the contrast structure layer is arranged on the first side of the electromagnetic shielding layer; and the gray value of the color of the contrast structure layer is greater than the gray value of the color of the first film layer. The application provides a shielding film and a circuit board, so that an identification code is arranged on the shielding film, and the clarity and resolution of the identification code are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electronic technology, and in particular to a shielding film and a circuit board. BACKGROUND

[0002] With the rapid development of electronic industry, electronic products are further developing towards miniaturization, light weight and high-density assembly, which greatly promotes the development of flexible circuit boards and gradually realizes the integration of component devices and wire connections. Flexible circuit boards can be widely used in mobile phones, liquid crystal displays, communications and aerospace industries.

[0003] With the integration of various functions of electronic products such as mobile phones, the internal components are gradually high-frequency and high-speed. For example, among the various functions of mobile phones, in addition to the original audio transmission function, the camera function has become a necessary function, and the wireless local area network (WLAN), global positioning system (GPS) and Internet function have also been popularized, in addition, future sensing components will gradually be integrated, and the trend of dramatic high-frequency and high-speed of mobile phone internal components is inevitable.

[0004] In current electronic products, various components are integrated inside the electronic products. In order to better trace the electronic product or better trace a certain component inside the electronic product, an identification code is often provided in the electronic product. By scanning the identification code, the information of the electronic product or a certain component inside the electronic product can be traced. In the past, the identification code (such as a two-dimensional code) was printed on a steel plate. However, due to the limitation of the size of the steel plate caused by the thinness of the electronic product, it is not easy to print the two-dimensional code on the steel plate. In the prior art, the identification code can also be printed on the soft plate of the electronic product by printing. However, due to the small size of the soft plate, the printed identification code is not clear, the precision does not meet the identification requirements, and the identification code cannot be printed on the soft plate with a small size. SUMMARY

[0005] The embodiments of the present application provide a shielding film and a circuit board to realize the setting of an identification code on the shielding film, thereby improving the clarity and resolution of the identification code.

[0006] In a first aspect, the embodiments of the present application provide a shielding film, comprising: a first film layer, a contrast structure layer and an electromagnetic shielding layer.

[0007] The first film layer is arranged on the first side of the electromagnetic shielding layer.

[0008] The contrast structure layer is arranged on the first side of the electromagnetic shielding layer.

[0009] The gray value of the color of the contrast structure layer is greater than the gray value of the color of the first film layer.

[0010] In a second aspect, the embodiment of the present application provides a shielding film, comprising a first film layer, a contrast structure layer and an electromagnetic shielding layer.

[0011] The first film layer is arranged on the first side of the electromagnetic shielding layer.

[0012] The contrast structure layer is arranged on the first side of the electromagnetic shielding layer.

[0013] The gray value of the color of the contrast structure layer is greater than the gray value of the color of the first film layer; and one of the contrast structure layer and the first film layer, which is farther away from the electromagnetic shielding layer, forms a hollow pattern of an identification code.

[0014] In a third aspect, the embodiment of the present application provides a circuit board, comprising a printed circuit board and the shielding film provided by any of the embodiments of the present application; the side, away from the first film layer, of the electromagnetic shielding layer of the shielding film is provided with a glue film layer.

[0015] The side of the glue film layer of the shielding film is attached to the printed circuit board.

[0016] In the present application, the shielding film comprises an electromagnetic shielding layer for shielding electromagnetic interference, the first side of the electromagnetic shielding layer is provided with a first film layer and a contrast structure layer, the first film layer can be arranged between the electromagnetic shielding layer and the contrast structure layer, or the contrast structure layer can be arranged between the electromagnetic shielding layer and the first film layer, the gray value of the color of the contrast structure layer needs to be greater than the gray value of the color of the first film layer, so that a relatively obvious light-dark contrast can be formed between the contrast structure layer and the first film layer. In the present embodiment, one of the contrast structure layer and the first film layer, which is farther away from the electromagnetic shielding layer, forms a hollow pattern of an identification code, so that a high-definition identification code can be obtained by a user under the strong light-dark or color contrast between the contrast structure layer and the first film layer, the identification precision and accuracy of the identification code are improved, and the components or electronic products identified by the identification code are conveniently traced. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a structural schematic diagram of a shielding film provided by the embodiment of the present application;

[0018] Figure 2 is a structural schematic diagram of another shielding film provided by the embodiment of the present application;

[0019] Figure 3 is a structural schematic diagram of another shielding film provided by the embodiment of the present application;

[0020] Figure 4is a structural schematic diagram of another shielding film provided by an embodiment of the present application;

[0021] Figure 5 is a structural schematic diagram of another shielding film provided by an embodiment of the present application;

[0022] Figure 6 is a structural schematic diagram of another shielding film provided by an embodiment of the present application;

[0023] Figure 7 is a planar structural schematic diagram of an electromagnetic shielding layer provided by an embodiment of the present application;

[0024] Figure 8 is a structural schematic diagram of another shielding film provided by an embodiment of the present application;

[0025] Figure 9 is a structural schematic diagram of another shielding film provided by an embodiment of the present application;

[0026] Figure 10 is a structural schematic diagram of another shielding film provided by an embodiment of the present application;

[0027] Figure 11 is a structural schematic diagram of a circuit board provided by an embodiment of the present application;

[0028] Figure 12 is a structural schematic diagram of an electronic device provided by an embodiment of the present application. DETAILED DESCRIPTION

[0029] The present application will be further described below in conjunction with the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present application, but not to limit the present application. In addition, it should be noted that, for the convenience of description, only the parts related to the present application are shown in the drawings, but not all the structures.

[0030] With the development of flexible circuit boards, an important indicator for evaluating the performance of flexible circuit boards is electromagnetic shielding (EMI Shielding). Under the driving of high frequency and high speed, the electromagnetic interference inside and outside the components, as well as the attenuation, insertion loss and jitter of signals in the transmission process gradually become more serious. Generally, electronic products need to attach shielding films on printed circuit boards to achieve electromagnetic interference shielding. In view of the fact that it is not easy to set the identification code on electronic products due to the size specification, the embodiments of the present application creatively set the identification code on the shielding film to improve the clarity and resolution of the identification code.

[0031] Specifically, the embodiments of the present application provide a shielding film, comprising: a first film layer, a contrast structure layer and an electromagnetic shielding layer;

[0032] The first film layer is arranged on the first side of the electromagnetic shielding layer;

[0033] The contrast structure layer is arranged on the first side of the electromagnetic shielding layer;

[0034] The gray value of the color of the contrast structure layer is greater than the gray value of the color of the first film layer.

[0035] In the embodiment of the present application, as long as the gray value of the color of the contrast structure layer is greater than the gray value of the color of the first film layer, the device can identify the color of the two and further process to form a clear and distinguishable identification code after the identification code is formed, and there is no limitation on how much the gray value of the color of the contrast structure layer should be greater than the gray value of the color of the first film layer.

[0036] In the embodiment of the present application, the shielding film includes an electromagnetic shielding layer for shielding electromagnetic interference, and the first side of the electromagnetic shielding layer is provided with a first film layer and a contrast structure layer. The first film layer can be arranged between the electromagnetic shielding layer and the contrast structure layer, or the contrast structure layer can be arranged between the electromagnetic shielding layer and the first film layer. The gray value of the color of the contrast structure layer needs to be greater than the gray value of the color of the first film layer, so that a relatively obvious light and shade contrast can be formed between the contrast structure layer and the first film layer. In this embodiment, the layer farther from the electromagnetic shielding layer among the contrast structure layer and the first film layer forms the hollow pattern of the identification code, so that the user can obtain a high-precision identification code under the strong light and shade or color contrast between the contrast structure layer and the first film layer, improve the identification precision and accuracy of the identification code, and facilitate the traceability of the components or electronic products identified by the identification code.

[0037] The above is the core idea of the present application. The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0038] Figure 1 is a structural schematic diagram of a shielding film provided by the embodiment of the present application, as shown in Figure 1 The shielding film includes a first film layer 11, a contrast structure layer 12 and an electromagnetic shielding layer 13. The material of the electromagnetic shielding layer 13 is a conductive material with good shielding performance, which can realize effective electromagnetic interference shielding. Optionally, the material of the electromagnetic shielding layer 13 can be copper, which has the characteristics of good electrical properties, high shielding performance, high transmission quality, high reliability and the like while ensuring low cost. Of course, the material of the electromagnetic shielding layer 13 can also be aluminum, silver and other metal materials, which are not limited in the embodiment. Optionally, as shown in Figure 2 Figure 2 ​Figure 2 is a structural schematic diagram of another shielding film provided by the embodiment of the present application. The shielding film can further include an adhesive film layer 14 arranged on the side of the electromagnetic shielding layer 13 away from the first film layer 11, for realizing the connection of the electromagnetic shielding layer 13 and the circuit board.

[0039] The first film layer 11 is used for insulating and supporting the electromagnetic shielding layer 13, and to some extent, blocks the water and oxygen from invading the electromagnetic shielding layer 13. The first film layer 11 is preferably black or a color with a gray value closer to black, such as dark blue. The embodiment does not limit the specific color of the first film layer 11. Optionally, the first film layer 11 can include at least one of epoxy resin, rubber, modified epoxy resin, polyimide, polyurethane resin, acrylic resin, modified acrylic resin, polyester, polyphenylene sulfide, polyethylene terephthalate, liquid crystal polymer and ink. The embodiment mixes at least one of the above materials with other materials to form a dark color with a lower gray value.

[0040] Optionally, the color of the first film layer 11 can be black. The first film layer 11 can include at least one of black polyimide and black ink. The black polyimide has good water vapor barrier effect, and the black ink has strong flame retardant effect. The first film layer 11 can be arranged as black polyimide material or black ink material. In addition, the first film layer 11 can include black polyimide and black ink at the same time to enhance the protection of the electromagnetic shielding layer 13. Optionally, in order to adapt to the thin trend of electronic products, the thickness of the first film layer 11 ranges from 0.5 μm to 40 μm, so as to reduce the thickness of the first film layer 11 as much as possible. Optionally, the thickness of the first film layer 11 can be 4 μm. Under the premise of good insulation and protection performance, the first film layer 11 is thinned.

[0041] The contrast structure layer 12 is used to form an obvious color or brightness difference with the first film layer 11. The gray value of the color of the contrast structure layer 12 is greater than the gray value of the color of the first film layer 11. The embodiment converts the color color into a high-quality gray gradient color using the gray parameter, so as to detect the contrast of the brightness of the contrast structure layer 12 and the first film layer 11. The gray value uses black tone to represent various colors, that is, using black as the reference color, different colors are displayed with different saturation of black. The black and white are divided into 0-255 kinds of gray. The gray value of white is 255, and the gray value of black is 0. In the embodiment, the gray value of the color of the contrast structure layer 12 is limited to be greater than the gray value of the color of the first film layer 11. Preferably, the gray value of the color of the contrast structure layer 12 is limited to be greatly different from the gray value of the color of the first film layer 11. For example, the color of the contrast structure layer 12 is silver, and the gray value of silver is large. Therefore, the silver of the contrast structure layer 12 forms a sharp contrast with the dark color of the first film layer 11.

[0042] The contrast structure layer 12 and the first film layer 11 are located on the same side of the electromagnetic shielding layer 13, and the arrangement order of the contrast structure layer 12 and the first film layer 11 is variable, for example, as... Figure 2 As shown, the contrast structure layer 12 can be disposed between the first film layer 11 and the electromagnetic shielding layer 13, or, as... Figure 3 As shown, Figure 3 This is a schematic diagram of another shielding film provided in an embodiment of the present invention. The first film layer 11 can be disposed between the contrast structure layer 12 and the electromagnetic shielding layer 13. As long as the contrast structure layer 12 and the first film layer 11 are superimposed to form a clear contrast, it is acceptable. Regardless of whether the contrast structure layer 12 and the first film layer 11 are... Figure 1 The order of settings in the middle, or Figure 3 The arrangement of the elements, with the outermost layer forming the cutout graphic of the identification code, ensures that the color of the layer exposed by this cutout graphic creates a significant brightness difference with the outermost layer, making the identification code clearer and easier for users to accurately identify. Specifically, for example... Figure 2 As shown, when the first film layer 11 is placed on the outermost side, a cutout pattern of the identification code needs to be formed on the first film layer 11. The cutout pattern of the first film layer 11 exposes a lighter-colored (higher brightness) contrast structure layer 12, forming a clearer identification code. For example... Figure 3 As shown, when the contrast structure layer 12 is disposed on the outermost side, a cutout pattern of the identification code needs to be formed on the contrast structure layer 12. The cutout pattern on the contrast structure layer 12 exposes the dark first film layer 11, forming a clear identification code. Optionally, the cutout pattern can be formed by laser ablation; for example, ultraviolet lasers and carbon dioxide lasers can be used for ablation.

[0043] Optionally, the difference between the grayscale value of the color of the contrast structure layer 12 and the grayscale value of the color of the first film layer 11 is greater than or equal to a first grayscale threshold; if the first grayscale threshold is greater than or equal to 10, then the difference between the grayscale value of the color of the contrast structure layer 12 and the grayscale value of the color of the first film layer 11 is at least 10, so that a more obvious difference in brightness is formed between the contrast structure layer 12 and the first film layer 11, thereby improving the accuracy of the identification code recognition device in recognizing the identification code formed by the contrast structure layer 12 and the first film layer 11.

[0044] To further increase the brightness difference between the contrast structure layer 12 and the first film layer 11, the first grayscale threshold can be set to 50. Then, the difference between the grayscale value of the color of the contrast structure layer 12 and the grayscale value of the color of the first film layer 11 is at least 50. The color brightness of the contrast structure layer 12 is stronger, and the color brightness of the first film layer 11 is weaker. This further increases the contrast between the contrast structure layer 12 and the first film layer 11, thereby improving the recognition accuracy and precision of the identification code.

[0045] On the basis of the above-mentioned embodiment, the first gray scale threshold can be further limited to 100, and the difference between the gray scale value of the color of the contrast structure layer 12 and the gray scale value of the color of the first film layer 11 is at least 100, for example, if the gray scale value of the color of the first film layer 11 is 0, the difference between the gray scale value of the color of the contrast structure layer 12 and the gray scale value of the color of the first film layer 11 is at least 100, or even 255, and then the gray scale value of the contrast structure layer 12 can be greater than or equal to 100. In the case of a difference of 255 in the gray scale value, one of the contrast structure layer 12 and the first film layer 11 is pure black, and the other is pure white, that is, the gray scale values of the two are 255 and 0, respectively, and the difference in brightness or color is large, thereby further enhancing the clarity of the identification code.

[0046] It should be noted that in the present embodiment, the shielding film is attached to the printed circuit board through the side provided with the adhesive film layer 14, and is used to rapidly guide the interference signals generated by the electronic device from the electromagnetic shielding layer 13 to the ground plate or ground wire of the printed circuit board. Figure 4 is another structural diagram of a shielding film provided by the embodiment of the present application. Optionally, the side of the electromagnetic shielding layer 13 close to the adhesive film layer 14 can be roughened to form a plurality of protruding structures 131; the protruding structures 131 are used to pierce the adhesive film layer 14 and connect with the ground end of the printed circuit board, the protruding structures 131 can realize the connection between the electromagnetic shielding layer 13 and the ground end, and the protruding structures 131 make the electromagnetic shielding layer 13 and the adhesive film layer 14 closely attached, thereby avoiding the separation of the electromagnetic shielding layer 13 and the adhesive film layer 14. In addition, when the amount of adhesive of the adhesive film layer 14 is insufficient, the separation between the shielding film and the printed circuit board can occur, and when the amount of adhesive of the adhesive film layer 14 is too much, the edge of the printed circuit board can be prone to overflow. The protruding structures 131 in the present embodiment can extrude the overflowed adhesive to the recessed part of the adhesive film layer 14 when the shielding film and the printed circuit board are pressed together, thereby increasing the adhesive capacity between the electromagnetic shielding layer 13 and the printed circuit board, and avoiding the separation between the shielding film and the printed circuit board.

[0047] It should be noted that in the production process of the above-mentioned shielding film, the above-mentioned first film layer 11, contrast structure layer 12, electromagnetic shielding layer 13 and adhesive film layer 14 are all arranged on the carrier film, and the carrier film supports the above-mentioned film layers. After the first film layer 11, contrast structure layer 12 and electromagnetic shielding layer 13 are formed on the carrier film, the electromagnetic shielding layer 13 is roughened to form the protruding structures 131, and the adhesive film layer 14 is pressed onto the protruding structures 131 of the electromagnetic shielding layer 13 to form the base film material of the shielding film. Thereafter, the base film material of the shielding film needs to be peeled off from the carrier film, and the shielding film is ablated on the side away from the adhesive film layer 14 to form the hollow pattern of the identification code.

[0048] Figure 5is another structural schematic diagram of a shielding film provided by an embodiment of the present application. In this embodiment, the side of the electromagnetic shielding layer 13 close to the adhesive film layer 14 can be roughened, and the adhesive film layer 14 can optionally include a plurality of conductive particles 141. The conductive particles 141 are used to pierce the adhesive film layer 14 to connect the ground of the printed circuit board and the electromagnetic shielding layer 13. Figure 4 , Figure 5 The adhesive film layer 14 includes a plurality of conductive particles 141, which are agglomerated to form larger particles that can pierce the adhesive film layer 14 to connect the ground of the printed circuit board and the electromagnetic shielding layer 13. In this embodiment, roughening of the electromagnetic shielding layer 13 is not required during manufacturing, and the adhesive film layer 14 can be tightly attached to the electromagnetic shielding layer 13 to form the base film material of the shielding film.

[0049] In addition, the side of the electromagnetic shielding layer 13 close to the adhesive film layer 14 can be roughened to form a protruding structure, and then the adhesive film layer 14 with conductive particles 141 can be applied, as shown in Figure 6 , Figure 6 is another structural schematic diagram of a shielding film provided by an embodiment of the present application. In this embodiment, the electromagnetic shielding layer 13 is roughened to form a protruding structure 131, and the adhesive film layer 14 includes a plurality of conductive particles 141. The conductive particles 141 can pierce the adhesive film layer 14 and electrically connect to the protruding structure 131, thereby further enhancing the conductivity between the electromagnetic shielding layer 14 and the ground layer of the circuit board and solving the problem of delamination between the shielding film and the circuit board caused by insufficient adhesive volume.

[0050] Optionally, as shown in Figure 7 , Figure 7 is a planar structural schematic diagram of an electromagnetic shielding layer provided by an embodiment of the present application. The electromagnetic shielding layer 13 includes a plurality of through holes 132, which are beneficial for the volatiles of the adhesive film to be exhausted through the through holes 132 of the electromagnetic shielding layer 13 at high temperatures, thereby preventing the volatiles of the adhesive film from being difficult to exhaust at high temperatures and avoiding the electromagnetic shielding layer 13 from bubbling and delaminating to cause the electromagnetic shielding film and the ground layer of the circuit board to peel off, and further ensuring that the electromagnetic shielding film is grounded and the interference charge is discharged.

[0051] Optionally, the through holes 132 can be regularly or irregularly distributed on the electromagnetic shielding layer 13. As shown in Figure 7 , the through holes 132 are regularly distributed on the electromagnetic shielding layer 13, which means that each through hole 132 has the same shape and is uniformly distributed on the electromagnetic shielding layer 13. The through holes 132 are irregularly distributed on the electromagnetic shielding layer 13, which means that each through hole 132 has a different shape and is disorderly distributed on the electromagnetic shielding layer 13. Preferably, as shown in Figure 7As shown, all through holes 132 have the same shape and are evenly distributed on the electromagnetic shielding layer 13. Furthermore, the through holes 132 can be circular or any other arbitrary shape. Figure 7 The example only illustrates that the through hole 132 is a circular through hole, but any other shape of through hole 132 is within the protection scope of the embodiments of the present invention.

[0052] The shielding film will be described in detail below according to the arrangement order of the first film layer 11 and the contrast structure layer 12, divided into two types:

[0053] The first option is to continue referring to... Figure 3 Optionally, in this embodiment, the contrast structure layer 12 can be disposed on the side of the first film layer 11 away from the electromagnetic shielding layer 13; the contrast structure layer 12 forms a hollowed-out pattern of the identification code. For example... Figure 3 As shown, in this embodiment, the material of the comparison structure layer 12 can be a metal, and the grayscale value of the metal is greater than the grayscale value of the first film layer 11, and the difference is preferably greater than or equal to 10. It should be noted that the metal layer can include at least one of elemental metal and metal alloy; this embodiment does not limit this. When the comparison structure layer 12 is a metal layer, after the user forms a perforated pattern on the metal layer, optionally, an insulating film is provided on the side of the metal layer away from the electromagnetic shielding layer 13, and an opening is formed on the insulating film at the position corresponding to the perforated pattern of the identification code to expose the identification code for user identification, thereby preventing short circuits caused by contact between the metal layer and external electronic components. Furthermore, if the insulating film is a colorless and transparent insulating film, the opening may not be provided, and the identification code can still be exposed for user identification.

[0054] Alternatively, the contrast layer 12 can be an adhesive layer or an ink layer with a grayscale value greater than that of the first film layer 11. While protecting the electromagnetic shielding layer 13, the contrast layer 12 and the exposed first film layer 11 with the cutout pattern form a clear identification code. In this embodiment, the adhesive layer can be a thermosetting adhesive.

[0055] Optionally, the contrast structure layer 12 can be a white adhesive layer or a white ink layer. In this embodiment, the contrast structure layer 12 is a white adhesive layer or a white ink layer, so the grayscale value of the contrast structure layer 12 is 255, while the color of the first film layer 11 is preferably black, and the grayscale value of the first film layer 11 is 0. The contrast between black and white is relatively strong, making it easier to form a clearer identification code. In addition, the adhesive layer or ink layer can also be gray, yellow, or other colors with high grayscale values, and this embodiment does not limit this.

[0056] The second option is to continue referring to... Figure 2Optionally, the first film layer 11 can be arranged on the side of the contrast structure layer 12 away from the electromagnetic shielding layer 13; the first film layer 11 forms the hollow pattern of the identification code. Optionally, the contrast structure layer 12 can be a glue layer or an ink layer, and the gray value of the color of the glue layer or the ink layer is greater than the gray value of the color of the first film layer 11, and the gray value of the color of the glue layer or the ink layer is preferably greater than or equal to 160.

[0057] Optionally, the contrast structure layer 12 can be a white or colorless glue layer; or the contrast structure layer 12 is a white ink layer. The material of the contrast structure layer 12 can be selected from at least one of modified epoxy resin, modified acrylic, modified rubber, modified thermoplastic polyimide, modified polyester, thermoplastic resin, thermosetting resin, and melamine glue. In this embodiment, the contrast structure layer 12 is a white glue layer or a white ink layer, so the gray value of the color of the contrast structure layer 12 is 255, and the gray value of the color of the first film layer 11 is preferably 0. The contrast between black and white is strong, and a clearer identification code is easily formed. In addition, the glue layer or the ink layer can also be gray, yellow, and other colors with high gray values, which are not limited in this embodiment. It should be noted that when the contrast structure layer 12 is arranged between the first film layer 11 and the electromagnetic shielding layer 13, the colorless glue layer can be selected for the contrast structure layer 12, which effectively protects the electromagnetic shielding layer 13 and prevents the electromagnetic shielding layer 13 from being exposed in the hollow pattern. And the contrast structure layer 12 is colorless, so the electromagnetic shielding layer 13 is exposed through the hollow pattern, and the black color of the first film layer 11 also contrasts with the color of the electromagnetic shielding layer 13, forming a clearer identification code. For example, if the material of the electromagnetic shielding layer 13 is copper, the color of the electromagnetic shielding layer 13 is red copper, and the red copper color is easily distinguished from the black color. The colorless contrast structure layer 12 effectively protects the copper from being oxidized in the air and makes it difficult to distinguish the color between the first film layer 11 and the electromagnetic shielding layer 13.

[0058] Optionally, the contrast structure layer 12 can also be a metal layer. The gray value of the color of the metal is greater than the gray value of the color of the first film layer 11, and the gray value of the color of the metal is preferably greater than or equal to 10.

[0059] Optionally, the material of the contrast structure layer 12 is at least one of nickel, silver, platinum, titanium, aluminum, cobalt and chromium; or the material of the contrast structure layer is an alloy formed by at least two of nickel, silver, platinum, titanium, aluminum, cobalt and chromium; or the material of the contrast structure layer is a combination between alloys formed by at least two of nickel, silver, platinum, titanium, aluminum, cobalt and chromium. It is easy to understand that the more black and white the identification code is, the better, and therefore the color of the metal material of the contrast structure layer 12 needs to be light enough, preferably a silver-colored or silver-white metal material. In the embodiment, at least one of nickel, silver, platinum, titanium, aluminum, cobalt and chromium, or an alloy formed by at least two of nickel, silver, platinum, titanium, aluminum, cobalt and chromium, or a combination between alloys formed by at least two of nickel, silver, platinum, titanium, aluminum, cobalt and chromium is selected as the material of the contrast structure layer 12. The above-mentioned materials are all white, silver or close to silver in color, and for example, nickel or a nickel-chromium alloy can be selected as the material of the contrast structure layer 12. In addition, the contrast structure layer 12 can also be other light-colored metals with low gray value, which are not limited in the embodiment.

[0060] Figure 8 is another structural diagram of a shielding film provided by the embodiment of the present application. Optionally, the contrast structure layer 12 can include a first metal layer 121 and a second metal layer 122; the first metal layer 121 is formed on the side of the first film layer 11 close to the electromagnetic shielding layer 13 by a sputtering process; and the second metal layer 122 is formed on the side of the first metal layer 121 away from the first film layer 11 by an electroplating process.

[0061] In addition to the limitation of the gray value, the embodiment also has certain requirements for the flatness of the contrast structure layer 12. Because the rougher the surface of the contrast structure layer 12 is, the darker the light on the surface of the contrast structure layer 12 is, and the resolution between the contrast structure layer 12 and the first film layer 11 is reduced, the embodiment can divide the contrast structure layer 12 into two layers, that is, a first metal layer 121 is first formed on the first film layer 11 by a sputtering process, the sputtering process forms a dense and flat metal surface, which is convenient for contrast with the first film layer 11, and then a second metal layer 122 is formed on the flat first metal layer 121 by an electroplating process. Optionally, the thickness of the first metal layer 121 can be in the range of 0.1 μm to 10 μm. The thickness of the second metal layer 122 can be in the range of 0.1 μm to 10 μm. Optionally, if the thickness of the second metal layer 122 is in the range of 0.2 μm to 0.4 μm, the resistance of the second metal layer 122 in a unit area (1 cm x 1 cm) can be set in the range of 15 mΩ to 200 mΩ, and preferably can be set to 30 mΩ.

[0062] In addition, the first metal layer 121 can be formed by other processes besides sputtering process, for example, one or more of chemical plating, physical vapor deposition, chemical vapor deposition, evaporation plating, sputtering plating, electroplating and hybrid plating, and the present embodiment is not limited to the process of forming the first metal layer 121. Optionally, the first metal layer 121 is preferably formed by sputtering process.

[0063] In Figure 8 In the embodiment shown, when the identification code is to be formed by ablation, the laser energy forms a hollow pattern on the first film layer, so that the color of the first metal layer 121 is exposed, and therefore the gray value corresponding to the color of the first metal layer 121 is preferably lower than the gray value corresponding to the color of the second metal layer 122. For example, the first metal layer 121 can be Ag, and the second metal layer 122 can be Ni.

[0064] Figure 9 is another structure of a shielding film provided by the present embodiment, and the first metal layer can include a first sputtered metal layer 1211 and a second sputtered metal layer 1212. The first sputtered metal layer 1211 is disposed between the first film layer 11 and the second sputtered metal layer 1212. The gray value of the color of the first sputtered metal layer 1211 is greater than the gray value of the color of the second sputtered metal layer 1212.

[0065] The present embodiment can be provided with two sputtered metal layers, because the laser energy may, in fact, penetrate the first sputtered metal layer 1211 when forming the hollow pattern of the identification code by ablating the first film layer 11, and the second sputtered metal layer 1212 can be provided to increase the protection and maintain the high flatness of the sputtered metal layer exposed by the hollow pattern. In addition, the gray value of the color of the first sputtered metal layer 1211 can be greater than the gray value of the color of the second sputtered metal layer 1212. For example, the first sputtered metal layer 1211 can be silver, and the second sputtered metal layer 1212 can be nickel, so that the metal surface of silver can form a sharp color contrast with the dark first film layer 11, thereby improving the clarity of the identification code.

[0066] Figure 10is another structural schematic diagram of a shielding film provided by the embodiment of the present application. Optionally, the contrast structure layer 12 can further include a second film layer 15; the second film layer 15 is arranged between the first film layer 11 and the first metal layer 121; the difference between the gray value of the color of the second film layer 15 and the gray value of the color of the first film layer 11 is greater than or equal to a first gray threshold value; the first gray threshold value is greater than or equal to 10. The second film layer 15 is arranged between the first film layer 11 and the first metal layer 121. When the first metal layer 121 includes a first sputtering metal layer and a second sputtering metal layer, the second film layer 15 is arranged between the first film layer 11 and the first sputtering metal layer, thereby further enhancing the protection of the first metal layer 121. For example, because of the arrangement of the second film layer 15, the situation that the first sputtering metal layer is possibly penetrated by laser energy is completely avoided, and the first sputtering metal layer is protected. Therefore, the gray value of the color of the second film layer 15 also needs to be greater than the gray value of the first film layer 11, and the difference between the gray value of the color of the second film layer 15 and the gray value of the color of the first film layer 11 is preferably greater than or equal to the first gray threshold value; the first gray threshold value is greater than or equal to 10. The difference between the gray value of the color of the second film layer 15 and the gray value of the color of the first film layer 11 is at least 10, so that a relatively obvious light-dark difference is formed between the second film layer 15 and the first film layer 11, and the accuracy of the identification code recognition device in identifying the identification code formed by the second film layer 15 and the first film layer 11 is improved. Preferably, the first gray threshold value can be 50 or 100, which can further increase the light-dark contrast between the second film layer 15 and the first film layer 11, and improve the identification precision and accuracy of the identification code. Optionally, the second film layer 15 can be white or colorless; the thickness of the second film layer 15 can range from 0.5 μm to 30 μm. The white second film layer 15 is relatively strong compared with the dark first film layer 11, and is easy to form a clearer identification code. In addition, the second film layer 15 can be colorless, so that the color of the first metal layer 121 can be exposed by the hollow pattern through the second film layer 15.

[0067] On the basis of the above-mentioned embodiment, the embodiment of the present application further provides a shielding film, which continues to refer to FIG. 1 and includes a first film layer 11, a contrast structure layer 12 and an electromagnetic shielding layer 13.

[0068] The first film layer 11 is arranged on the first side of the electromagnetic shielding layer 13.

[0069] The contrast structure layer 12 is arranged on the first side of the electromagnetic shielding layer 13.

[0070] Among the contrast structure layer 12 and the first film layer 11, the layer farther from the electromagnetic shielding layer 13 forms a hollow pattern of an identification code.

[0071] In the embodiment of the present application, the shielding film comprises an electromagnetic shielding layer for shielding electromagnetic interference, a first film layer and a contrast structure layer are arranged on a first side of the electromagnetic shielding layer. The first film layer can be arranged between the electromagnetic shielding layer and the contrast structure layer, or the contrast structure layer can be arranged between the electromagnetic shielding layer and the first film layer. The gray value of the color of the contrast structure layer needs to be greater than the gray value of the color of the first film layer, so that a relatively obvious light and shade contrast can be formed between the contrast structure layer and the first film layer. In the embodiment, the layer of the contrast structure layer and the first film layer which is far away from the electromagnetic shielding layer forms the hollow pattern of the identification code, so that under the strong light and shade or color contrast of the contrast structure layer and the first film layer, the user can obtain the identification code with high clarity, improve the identification precision and accuracy of the identification code, and facilitate the traceability of the components or electronic products identified by the identification code.

[0072] Optionally, the identification code can include at least one of a bar code, a two-dimensional code and characters. The identification code is a unique identification mark for identifying components or electronic products. The identification code can include digital, alphabetical and other character patterns, or can be a bar code or a two-dimensional code. The shielding film of the embodiment can include at least one of the above bar code, two-dimensional code and characters to identify the corresponding components or electronic products. For example, the shielding film needs to be attached to the printed circuit board of the electronic device, and the identification code of the component can be arranged at the position corresponding to the component on the shielding film. A plurality of identification codes can be arranged on the shielding film to correspond to a plurality of components one by one, thereby solving the problem that the printed identification code is not clear due to the lack of a steel plate with sufficient size to set the identification code, and effectively improving the resolution and identification accuracy of the identification code. Optionally, the hollow pattern is formed by laser ablation. For example, ultraviolet laser and carbon dioxide laser can be used for ablation of the hollow pattern.

[0073] It should be noted that when ablation of the above hollow pattern is performed, there can be two cases:

[0074] First, only one layer of the contrast structure layer 12 and the first film layer 11 far away from the electromagnetic shielding layer 13 is ablated to form the hollow pattern of the identification code, and the other layer close to the electromagnetic shielding layer 13 is not ablated, that is, the ablation depth of the hollow pattern is the thickness of the layer of the contrast structure layer 12 and the first film layer 11 far away from the electromagnetic shielding layer 13. The hollow pattern exposes the layer of the contrast structure layer 12 and the first film layer 11 close to the electromagnetic shielding layer 13 which is not etched, and the contrast structure layer 12 and the first film layer 11 form the identification code.

[0075] Secondly, while the hollow pattern of the identification code is formed by burning through one layer of the contrast structure layer 12 and the first film layer 11 far from the electromagnetic shielding layer 13, the other layer close to the electromagnetic shielding layer 13 can be partially ablated. In this embodiment, the layer close to the electromagnetic shielding layer 13 is partially ablated but not completely ablated, and after the ablation of the identification code is completed, the hollow pattern can also expose the layer of the contrast structure layer 12 and the first film layer 11 close to the electromagnetic shielding layer 13, so that the contrast structure layer 12 and the first film layer 11 form the identification code. Specifically, the layer of the contrast structure layer 12 and the first film layer 11 close to the electromagnetic shielding layer 13 forms a groove pattern; the vertical projection of the hollow pattern on the plane where the electromagnetic shielding layer is located completely coincides with the groove pattern. The layer of the contrast structure layer 12 and the first film layer 11 close to the electromagnetic shielding layer 13 is partially ablated to form the groove pattern, and because the groove pattern and the hollow pattern are formed by the same process, the vertical projection of the hollow pattern on the plane where the electromagnetic shielding layer is located completely coincides with the groove pattern.

[0076] Optionally, continuing to refer to Figure 3 The contrast structure layer 12 can be arranged on the side of the first film layer 11 away from the electromagnetic shielding layer 13; the contrast structure layer 12 forms the hollow pattern of the identification code. In this embodiment, when the contrast structure layer 12 is ablated to form the hollow pattern of the identification code, only the contrast structure layer 12 can be ablated, and the first film layer 11 is not ablated; or when the contrast structure layer 12 is ablated to form the hollow pattern of the identification code, the first film layer 11 can be partially ablated to form a groove pattern at the same time, and the vertical projection of the hollow pattern on the plane where the electromagnetic shielding layer is located completely coincides with the groove pattern.

[0077] As shown in Figure 3 In this embodiment, the material of the contrast structure layer 12 can be metal, the gray value of the color of the metal is greater than the gray value of the color of the first film layer 11, and the difference between the gray value of the color of the metal and the gray value of the color of the first film layer 11 is preferably greater than or equal to 10.

[0078] Optionally, the contrast structure layer 12 can be a glue layer or an ink layer. The contrast structure layer 12 can be a glue layer or an ink layer with a gray value greater than the first film layer 11. While the electromagnetic shielding layer 13 is protected, the contrast structure layer 12 and the first film layer 11 exposed by the hollow pattern form a clear identification code. In this embodiment, the above-mentioned glue layer can be a thermosetting glue.

[0079] Optionally, the contrast structure layer 12 can be a white glue layer or a white ink layer. In the embodiment, the contrast structure layer 12 is a white glue layer or a white ink layer, the gray value of the color of the contrast structure layer 12 is 255, and the color of the first film layer 11 is preferably black, the gray value of the color of the first film layer 11 is 0, the contrast between black and white is strong, and a clearer identification code is easy to form. In addition, the glue layer or the ink layer can also be gray, yellow or other colors with a higher gray value, which is not limited in the embodiment.

[0080] Optionally, continuing to refer to Figure 1 , the first film layer 11 can also be arranged on the side of the contrast structure layer 12 away from the electromagnetic shielding layer 13; and the first film layer 11 forms a hollow pattern of the identification code. In the embodiment, when the first film layer 11 is ablated to form the hollow pattern of the identification code, only the first film layer 11 is ablated, and the contrast structure layer 12 is not ablated; or when the first film layer 11 is ablated to form the hollow pattern of the identification code, the contrast structure layer 12 is also partially ablated to form a groove pattern, and the vertical projection of the hollow pattern on the plane of the electromagnetic shielding layer completely overlaps the groove pattern. Optionally, the contrast structure layer 12 can be one or a combination of two or more of a glue layer, an ink layer and a metal layer.

[0081] Optionally, the contrast structure layer 12 can be a glue layer or an ink layer, and the gray value of the color of the glue layer or the ink layer is greater than the gray value of the color of the first film layer 11, and the difference between the gray value of the color of the glue layer or the ink layer and the gray value of the color of the first film layer 11 is preferably greater than or equal to 10. Optionally, the contrast structure layer 12 can be a white or colorless glue layer; or the contrast structure layer 12 is a white ink layer. The material of the contrast structure layer 12 can be selected from at least one of modified epoxy resin, modified acrylic, modified rubber, modified thermoplastic polyimide, modified polyester, thermoplastic resin, thermosetting resin, and melamine glue. In the embodiment, the contrast structure layer 12 is a white glue layer or a white ink layer, and the gray value of the color of the contrast structure layer 12 is 255, and the gray value of the color of the first film layer 11 is preferably 0, and the contrast between black and white is strong, and a more clear identification code is easily formed. In addition, the glue layer or the ink layer can also be gray, yellow and other colors with low gray value, which is not limited in the embodiment. It should be noted that when the contrast structure layer 12 is arranged between the first film layer 11 and the electromagnetic shielding layer 13, the contrast structure layer 12 can be a colorless glue layer, which effectively protects the electromagnetic shielding layer 13 from being exposed in the hollowed-out pattern. And the contrast structure layer 12 is colorless, so the electromagnetic shielding layer 13 is exposed through the hollowed-out pattern, and the black of the first film layer 11 also contrasts with the color of the electromagnetic shielding layer 13, forming a relatively clear identification code. For example, the material of the electromagnetic shielding layer 13 is copper, and the color of the electromagnetic shielding layer 13 is red copper. The red copper and black are easily distinguished, and the colorless contrast structure layer 12 effectively protects the copper from being oxidized in the air and makes it difficult to distinguish between the first film layer 11 and the copper.

[0082] Optionally, the contrast structure layer 12 can also be a metal layer. The gray scale value of the color of the metal is greater than the gray scale value of the color of the first film layer 11, and the difference is preferably greater than or equal to 10. Optionally, the material of the contrast structure layer 12 is at least one of nickel, silver, platinum, titanium, aluminum, cobalt and chromium; or the material of the contrast structure layer is an alloy formed by at least two of nickel, silver, platinum, titanium, aluminum, cobalt and chromium; or the material of the contrast structure layer is a combination between alloys formed by at least two of nickel, silver, platinum, titanium, aluminum, cobalt and chromium. It is easy to understand that the more black and white the identification code is, the better, so the color of the metal material of the contrast structure layer 12 needs to be light enough, preferably silver or silver-white metal material. In this embodiment, at least one of nickel, silver, platinum, titanium, aluminum, cobalt and chromium, or an alloy formed by at least two of nickel, silver, platinum, titanium, aluminum, cobalt and chromium, or a combination between alloys formed by at least two of nickel, silver, platinum, titanium, aluminum, cobalt and chromium is selected as the material of the contrast structure layer 12. The above-mentioned materials are all white, silver or silver-like color, and for example, nickel or nickel-chromium alloy can be selected as the material of the contrast structure layer 12. In addition, the contrast structure layer 12 can also be other light-colored metals with low gray scale value, which are not limited in this embodiment.

[0083] Optionally, the contrast structure layer 12 can include a first metal layer 121 and a second metal layer 122; the first metal layer 121 is formed on the side of the first film layer 11 close to the electromagnetic shielding layer 13 by a sputtering process; and the second metal layer 122 is formed on the side of the first metal layer 121 away from the first film layer 11 by an electroplating process.

[0084] In addition to the limitation of the gray scale value, this embodiment also has certain requirements for the flatness of the contrast structure layer 12. Because the rougher the surface of the contrast structure layer 12 is, the darker the light on the surface of the contrast structure layer 12 is, and the resolution between the first film layer 11 is reduced, so this embodiment can divide the contrast structure layer 12 into two layers, that is, first form a first metal layer 121 on the first film layer 11 by a sputtering process, the sputtering process forms a dense and flat metal surface, which is convenient for contrast with the first film layer 11, and then form a second metal layer 122 on the flat first metal layer 121 by an electroplating process. Optionally, the thickness of the first metal layer 121 can be 0.1 μm to 10 μm. The thickness of the second metal layer 122 can be 0.1 μm to 10 μm. Optionally, if the thickness of the second metal layer 122 is 0.2 μm to 0.4 μm, the resistance of the second metal layer 122 in a unit area (1 cm x 1 cm) can be set to 15 mΩ to 200 mΩ, and preferably to 30 mΩ.

[0085] In Figure 7In the shown embodiment, when the identification code is to be formed by ablation, the laser energy forms a hollow pattern on the first film layer, so that the color of the first metal layer is exposed, and thus the gray value corresponding to the color of the first metal layer is preferably lower than the gray value corresponding to the color of the second metal layer. For example, the first metal layer can be Ag, and the second metal layer can be Ni.

[0086] As shown in Figure 9 Optionally, the first metal layer can include a first sputtered metal layer 1211 and a second sputtered metal layer 1212, and the first sputtered metal layer 1211 is arranged between the first film layer 11 and the second sputtered metal layer 1212. The gray value of the color of the first sputtered metal layer 1211 is greater than the gray value of the color of the second sputtered metal layer 1212.

[0087] The embodiment can be provided with two sputtered metal layers, because the laser energy may, in fact, penetrate the first sputtered metal layer 1211 when forming the hollow pattern of the identification code by ablating the first film layer 11, and thus the second sputtered metal layer 1212 can be provided to increase the protection and keep the sputtered metal layer with higher flatness exposed in the hollow pattern. In addition, the gray value of the color of the first sputtered metal layer 1211 can be greater than the gray value of the color of the second sputtered metal layer 1212. For example, the first sputtered metal layer 1211 can be silver, and the second sputtered metal layer 1212 can be nickel. In this way, the metal surface of silver can form a sharp color contrast with the dark first film layer 11, and the clarity of the identification code is improved.

[0088] Based on the same concept, the embodiment of the present application also provides a circuit board, as shown in Figure 11 , and Figure 11 is a structural schematic diagram of a circuit board provided by the embodiment of the present application. The circuit board includes a printed circuit board 2 and the shielding film 1 provided by any embodiment of the present application. The electromagnetic shielding layer of the shielding film 1 is provided with a film layer away from the first film layer. The film layer of the shielding film 1 is attached to the printed circuit board 2. The circuit board of the embodiment includes the technical features of the shielding film provided by any embodiment of the present application, and has the beneficial effects of the shielding film provided by any embodiment of the present application.

[0089] The printed circuit board 2 is integrated with a large number of different functional components. In the embodiment, the shielding film 1 can be provided with the identification code of the components at positions corresponding to the components. The shielding film 1 can cover the printed circuit board as a whole to achieve electromagnetic shielding as a whole. The shielding film 1 can also include a plurality of small sub-shielding films, and each sub-shielding film is used to cover a corresponding area of the printed circuit board. The embodiment does not limit this. In addition, the identification code of the electronic device in which the circuit board is located can also be provided on the shielding film 1. For example, the identification code of the electronic device can be provided in the edge area of the shielding film 1.

[0090] The embodiment of the present application further provides an electronic device. Figure 12 is a structural schematic diagram of an electronic device provided by the embodiment of the present application, as shown in Figure 12 The electronic device provided by the embodiment of the present application comprises the circuit board 3 of any embodiment of the present application. The electronic device can be a mobile phone as shown in Figure 12 , a computer, a television, a smart wearable device, etc., and the embodiment is not specially limited to this.

[0091] Note that the above are only the preferred embodiments of the present application and the technical principles applied. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and those skilled in the art can make various obvious changes, re-adjustments and substitutions without departing from the protection scope of the present application. Therefore, although the present application has been described in more detail through the above embodiments, the present application is not limited to the above embodiments, and can further include more other equivalent embodiments without departing from the concept of the present application, and the scope of the present application is determined by the scope of the appended claims.

Claims

1. A shielding film, characterized by, The application relates to an electromagnetic shielding structure, which comprises the following parts: a first film layer, a contrast structure layer and an electromagnetic shielding layer; the first film layer is arranged on the first side of the electromagnetic shielding layer; the contrast structure layer is arranged on the first side of the electromagnetic shielding layer; the gray value of the color of the contrast structure layer is greater than the gray value of the color of the first film layer; the layer far from the electromagnetic shielding layer in the contrast structure layer and the first film layer forms a hollow pattern of an identification code; the difference between the gray value of the color of the contrast structure layer and the gray value of the color of the first film layer is greater than or equal to a first gray threshold value, and the first gray threshold value is greater than or equal to 10; the first film layer is arranged on the side of the contrast structure layer far from the electromagnetic shielding layer; the contrast structure layer is a metal layer; the contrast structure layer comprises a first metal layer and a second metal layer; the first metal layer is formed on the side of the first film layer close to the electromagnetic shielding layer; the second metal layer is formed on the side of the first metal layer far from the first film layer; the gray value of the color of the first metal layer is smaller than the gray value of the color of the second metal layer.

2. The shield film according to claim 1, characterized by The application further relates to an electromagnetic shielding structure, which comprises the following parts: a glue film layer; the glue film layer is arranged on the side of the electromagnetic shielding layer far from the first film layer.

3. The shield film according to claim 1, characterized by, The first film layer comprises at least one of the following materials: epoxy resin, rubber, modified epoxy resin, polyimide, polyurethane resin, acrylic resin, modified acrylic resin, polyester, polyphenylene sulfide, polyethylene terephthalate, liquid crystal polymer and ink; the thickness of the first film layer ranges from 0.5 to 40 microns.

4. The shield film according to claim 1, characterized by, The first gray threshold value is 50.

5. The shield film according to claim 1, characterized by, The first gray threshold value is 100.

6. The shielded film of claim 1, wherein, The material of the contrast structure layer is at least one of the following single elements: nickel, silver, platinum, titanium, aluminum, cobalt and chromium; or the material of the contrast structure layer is an alloy formed by at least two of the following elements: nickel, silver, platinum, titanium, aluminum, cobalt and chromium; or the material of the contrast structure layer is a combination of the alloys formed by at least two of the following elements: nickel, silver, platinum, titanium, aluminum, cobalt and chromium.

7. The shielded film of claim 1, wherein, The contrast structure layer comprises at least two metal layers.

8. The shielded film of claim 1, wherein, The contrast structure layer further comprises a second film layer; the second film layer is arranged between the first film layer and the metal layer; the difference between the gray value of the color of the second film layer and the gray value of the color of the first film layer is greater than or equal to the first gray threshold value; the first gray threshold value is greater than or equal to 10.

9. The shielded film of claim 8, wherein, The second film layer is white or colorless; the thickness of the second film layer ranges from 0.5 to 30 microns.

10. The shielded film of claim 2, wherein, The side of the electromagnetic shielding layer close to the glue film layer is roughened to form a plurality of convex structures; the convex structures are used for piercing the glue film layer and connecting the ground end of a printed circuit board; 11. The shield film according to claim 2 or 10, characterized by, a plurality of conductive particles are arranged in the glue film layer; the conductive particles are used for piercing the glue film layer to connect the ground end of a printed circuit board and the electromagnetic shielding layer.

12. The shielded film of claim 1, wherein, The electromagnetic shielding layer is provided with a plurality of through holes.

13. The shield film according to claim 1, characterized by, In the contrast structure layer and the first film layer, the layer close to the electromagnetic shielding layer forms a groove pattern; the vertical projection of the hollow pattern on the plane where the electromagnetic shielding layer is located is completely coincident with the groove pattern.

14. The shield film according to claim 1 or 13, characterized by, The first film layer is arranged on the side of the contrast structure layer away from the electromagnetic shielding layer; the first film layer forms the hollow pattern of the identification code.

15. The shielded film of claim 14, wherein, The contrast structure layer is one or a combination of two or more of a glue layer, an ink layer and a metal layer.

16. A wiring board, characterized by comprising: Comprise: A printed circuit board and the shielding film according to any one of claims 1-15; the electromagnetic shielding layer of the shielding film is arranged with a glue film layer on the side away from the first film layer; The side of the glue film layer of the shielding film is attached to the printed circuit board.

Images