A shielding film and a circuit board

Abstract

The present invention discloses a shielding film and a circuit board. The shielding film includes: a first film layer, a contrast structure layer, and an electromagnetic shielding layer; the first film layer is disposed on a first side of the electromagnetic shielding layer; the contrast structure layer is disposed on the first side of the electromagnetic shielding layer; wherein, the gray value of the color of the first film layer is greater than the gray value of the color of the contrast structure layer. The present invention provides a shielding film and a circuit board to implement setting an identification code on the screen film, thereby improving the clarity and resolution of the identification code.

Description

Technical Field

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

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

[0003] With the integration of various functions of electronic products such as mobile phones, their internal components are gradually becoming 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 an essential function, and wireless local area networks (WLAN), global positioning systems (GPS), and Internet access functions have also become popular. In addition, future sensing components will be gradually integrated, and the trend of high-frequency and high-speed internal components of mobile phones is inevitable.

[0004] In current electronic products, various components are integrated inside the electronic products. In order to better trace the electronic products or a certain component inside the electronic products, identification codes are often set inside the electronic products. By scanning the identification codes, the information of the electronic products or a certain component inside them can be traced. The prior art is to print the identification code (such as a two-dimensional code) on a steel plate. However, due to the thinness and lightness of the electronic products, the size of the steel plate is limited, resulting in difficulty in printing the two-dimensional code on the steel plate. In the prior art, printing can also be used to print the identification code on the flexible board of the electronic product. However, due to the small size of the flexible board, the printed identification code is not clear, and the accuracy cannot meet the recognition requirements. In addition, there is also a situation where the identification code cannot be printed on the flexible board with a small size. Summary of the Invention

[0005] Embodiments of the present invention provide a shielding film and a circuit board to set an identification code on the shielding film, thereby improving the clarity and resolution of the identification code.

[0006] In a first aspect, embodiments of the present invention provide a shielding film, including: a first film layer, a contrast structure layer, and an electromagnetic shielding layer;

[0007] The first film layer is disposed on a first side of the electromagnetic shielding layer;

[0008] The contrast structure layer is disposed on the first side of the electromagnetic shielding layer;

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

[0010] In a second aspect, an embodiment of the present invention provides a shielding film, including: a first film layer, a contrast structure layer, and an electromagnetic shielding layer;

[0011] The first film layer is disposed on a first side of the electromagnetic shielding layer;

[0012] The contrast structure layer is disposed on the first side of the electromagnetic shielding layer;

[0013] Among them, the gray value of the color of the first film layer is greater than the gray value of the color of the contrast structure layer; in the contrast structure layer and the first film layer, the layer farther from the electromagnetic shielding layer forms a hollowed-out pattern of an identification code.

[0014] In a third aspect, an embodiment of the present invention provides a circuit board, the circuit board includes a printed circuit board and the shielding film provided in any embodiment of the present invention; a glue film layer is provided on a side of the electromagnetic shielding layer of the shielding film away from the first film layer;

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

[0016] In the present invention, the shielding film includes an electromagnetic shielding layer for shielding electromagnetic interference. A first film layer and a contrast structure layer are provided on a first side of the electromagnetic shielding layer. The first film layer can be disposed between the electromagnetic shielding layer and the contrast structure layer, or the contrast structure layer can be disposed between the electromagnetic shielding layer and the first film layer. The gray value of the color of the first film layer needs to be greater than the gray value of the color of the contrast structure layer, so that a relatively obvious contrast in light and dark brightness can be formed between the contrast structure layer and the first film layer. In this embodiment, the layer farther from the electromagnetic shielding layer in the contrast structure layer and the first film layer forms a hollowed-out pattern of an identification code, so that under the strong contrast in light and dark or color between the contrast structure layer and the first film layer, the user can obtain an identification code with higher clarity, improving the recognition accuracy and accuracy of the identification code, and facilitating the traceability of the components or electronic products identified by the identification code. Description of the Drawings

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

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

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

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

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

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

[0023] Figure 7 It is a schematic plan view of an electromagnetic shielding layer provided by an embodiment of the present invention;

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

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

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

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

[0028] Figure 12 It is a schematic structural diagram of an electronic device provided by an embodiment of the present invention. Detailed implementation manners

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. In addition, it should be noted that for the sake of description, only parts related to the present invention rather than all structures are shown in the accompanying drawings.

[0030] With the development of flexible circuit boards, an important index for evaluating the performance of flexible circuit boards is electromagnetic shielding (Electromagnetic Interference Shielding, EMI Shielding). The electromagnetic interference inside and outside components caused by high-frequency and high-speed driving, as well as the attenuation, insertion loss, and jitter of signals during transmission, are gradually becoming serious. Generally, electronic products need to attach a shielding film to the printed circuit board to achieve electromagnetic interference shielding. Considering the current situation that it is not easy to set the identification code due to the size specifications of electronic products, the embodiments of the present invention 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 invention provide a shielding film, including: a first film layer, a contrast structure layer, and an electromagnetic shielding layer;

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

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

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

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

[0036] In the embodiment of the present invention, the shielding film includes an electromagnetic shielding layer for shielding electromagnetic interference. On the first side of the electromagnetic shielding layer, there are a first film layer and a contrast structure layer. The first film layer can be disposed between the electromagnetic shielding layer and the contrast structure layer, or the contrast structure layer can be disposed between the electromagnetic shielding layer and the first film layer. The gray value of the color of the first film layer needs to be greater than the gray value of the color of the contrast structure layer, so that a relatively obvious contrast in brightness 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 can form a hollowed-out pattern of the identification code, so that under the strong contrast in brightness or color between the contrast structure layer and the first film layer, the user can obtain a higher-clarity identification code, improving the recognition accuracy and accuracy of the identification code and facilitating the traceability of the components or electronic products identified by the identification code.

[0037] The above is the core idea of the present invention. Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention.

[0038] Figure 1 is a schematic structural diagram of a shielding film provided by an embodiment of the present invention. As Figure 1 shown, the shielding film includes a first film layer 11, a contrast structure layer 12, and an electromagnetic shielding layer 13. Among them, the material of the electromagnetic shielding layer 13 is a conductive material with good shielding performance, which can achieve effective electromagnetic interference shielding. Optionally, the material of the electromagnetic shielding layer 13 can be copper, which has good electrical characteristics, high shielding performance, high transmission quality, and good reliability while ensuring a relatively low cost. Of course, the material of the electromagnetic shielding layer 13 can also be metal materials such as aluminum and silver. This embodiment does not limit this. Optionally, as Figure 2 shown, Figure 2It is a schematic structural diagram of another shielding film provided by an embodiment of the present invention. The shielding film may further include an adhesive film layer 14, and the adhesive film layer 14 is disposed on the side of the electromagnetic shielding layer 13 away from the first film layer 11 for connecting the electromagnetic shielding layer 13 to the circuit board.

[0039] The first film layer 11 is used for insulating and supporting the electromagnetic shielding layer 13, and to a certain extent, blocking the intrusion of water and oxygen into the electromagnetic shielding layer 13. In this embodiment, the material of the first film layer 11 may be an adhesive layer or an ink layer. Optionally, the first film layer 11 may include at least one of modified epoxy resins, modified acrylics, modified rubbers, modified thermoplastic polyimides, modified polyesters, thermoplastic resins, thermosetting resins, and pressure-sensitive adhesives. In this implementation, at least one of the above materials is mixed with other materials to form a light color with a higher gray value. The first film layer 11 is preferably a color with a higher gray value. For example, white, or a color with a gray value closer to white such as light gray. The specific color of the first film layer 11 is not limited in this embodiment.

[0040] Optionally, the color of the first film layer 11 may be white; the first film layer 11 may be a white adhesive layer or a white ink layer. For example, the white adhesive layer may be white polyimide, and polyimide has a good water vapor barrier effect. The white ink has a strong flame retardant effect. The first film layer 11 may be set as a white polyimide material or a white ink material. In addition, the first film layer 11 may simultaneously include white polyimide and white ink to enhance the protection effect on the electromagnetic shielding layer 13. Optionally, in order to adapt to the trend of thinning of electronic products, the thickness range of the first film layer 11 is 0.5 μm to 40 μm, so as to minimize the thickness of the first film layer 11. Optionally, the thickness of the first film layer 11 may be selected as 4 μm to achieve the thinning of the first film layer 11 on the premise of having good insulation and protection performance.

[0041] The contrast structure layer 12 is used to form an obvious color or brightness difference with the first film layer 11, and the gray value of the color of the first film layer 11 is greater than the gray value of the color of the contrast structure layer 12. In this embodiment, gray parameters are used to convert the color into a high-quality gray gradient color to detect the contrast ratio of the brightness between the contrast structure layer 12 and the first film layer 11. Gray uses black tones to represent various colors, that is, black is used as the reference color, and different colors are displayed with black of different saturations. The range between black and white is divided into 0 to 255 gray levels. The gray value of white is 255, and the gray value of black is 0. In this embodiment, it is defined that the gray value of the color of the first film layer 11 is greater than the gray value of the color of the contrast structure layer 12. Preferably, the difference between the gray value of the color of the contrast structure layer 12 and the gray value of the color of the first film layer 11 can be defined to be relatively large. For example, if the color of the first film layer 11 is light yellow and the gray value of light yellow is relatively large, then the light yellow of the first film layer 11 forms a sharp contrast with the dark color of the contrast structure layer 12.

[0042] Optionally, the difference between the gray value of the color of the first film layer 11 and the gray value of the color of the contrast structure layer 12 is greater than or equal to the first gray threshold; the first gray threshold is greater than or equal to 10. In order to further increase the brightness difference between the contrast structure layer 12 and the first film layer 11, it can be defined that the difference between the gray value of the color of the first film layer 11 and the gray value of the color of the contrast structure layer 12 is greater than or equal to 10 and less than or equal to 255. Then, the difference between the gray value of the color of the first film layer 11 and the gray value of the color of the contrast structure layer 12 is at least 10, so as to form a relatively obvious light and dark difference between the contrast structure layer 12 and the first film layer 11, and improve the recognition accuracy of the identification code formed by the contrast structure layer 12 and the first film layer 11 by the identification code recognition device.

[0043] In order to further increase the brightness difference between the contrast structure layer 12 and the first film layer 11, the above-mentioned first gray threshold can be defined as 50. Then, the difference between the gray value of the color of the first film layer 11 and the gray value of the color of the contrast structure layer 12 is at least 50. The color brightness of the first film layer 11 is stronger, and the color brightness of the contrast structure layer 12 is smaller, further increasing the light and dark contrast between the contrast structure layer 12 and the first film layer 11, and improving the recognition accuracy and accuracy of the identification code.

[0044] Based on the above embodiments, in this embodiment, the first gray threshold can be further defined as 100. Then, the difference between the gray value of the color of the first film layer 11 and the gray value of the color of the contrast structure layer 12 is at least 100. For example, if the gray value of the color of the first film layer 11 is 255, the difference between the gray value of the color of the first film layer 11 and the gray value of the color of the contrast structure layer 12 is at least 100, and even 255. Then, the gray value of the contrast structure layer 12 can be selected to be less than or equal to 155. When the gray values differ by 255, one of the contrast structure layer 12 and the first film layer 11 is pure black and the other is pure white, that is, one of their gray values is 255 and the other is 0, and the brightness or color difference is large, further enhancing the clarity of the identification code.

[0045] Figure 3 is a schematic structural diagram of another shielding film provided by an embodiment of the present invention. Refer to Figure 2 and Figure 3 , optionally, the contrast structure layer 12 is disposed on a side of the first film layer 11 away from the electromagnetic shielding layer 13; or, the first film layer is disposed on a side of the contrast structure layer away from the electromagnetic shielding layer. The contrast structure layer 12 and the first film layer 11 are on the same side of the electromagnetic shielding layer 13, and the setting order of the contrast structure layer 12 and the first film layer 11 can be changed. For example, as Figure 2 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 shown, 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 superposed to form a distinct contrast. Whether the setting order of the contrast structure layer 12 and the first film layer 11 is Figure 1 or Figure 3 , the outermost layer is used to form the hollowed-out pattern of the identification code, and the color of the other layer exposed by the hollowed-out pattern can form a large brightness difference with the outermost layer, making the identification code clearer and facilitating accurate identification by the user. Specifically, as Figure 2 shown, when the first film layer 11 is disposed on the outermost side, a hollowed-out pattern of the identification code needs to be formed on the first film layer 11. Then, the hollowed-out pattern of the first film layer 11 exposes the contrast structure layer 12 with a darker color (lower brightness), forming a relatively clear identification code. As Figure 3 shown, when the contrast structure layer 12 is disposed on the outermost side, a hollowed-out pattern of the identification code needs to be formed on the contrast structure layer 12. Then, the hollowed-out pattern on the contrast structure layer 12 exposes the lighter first film layer 11, forming a clear identification code. Optionally, the above hollowed-out pattern can be formed by laser ablation. For example, ultraviolet laser and carbon dioxide laser can be used for ablation of the hollowed-out pattern.

[0046] It should be noted that in this embodiment, the shielding film is adhered to the printed circuit board through the side provided with the adhesive film layer 14, and is used to quickly conduct the interference signals generated by the electronic device from the electromagnetic shielding layer 13 to the ground plane or ground wire of the printed circuit board. Figure 4 It is a schematic structural diagram of another shielding film provided by an embodiment of the present invention. Optionally, the side of the electromagnetic shielding layer 13 close to the adhesive film layer 14 can be roughened to form a plurality of raised structures 131; the raised structures 131 are used to pierce through the adhesive film layer 14 to connect with the ground end of the printed circuit board. The raised structures 131 can realize the connection between the electromagnetic shielding layer 13 and the ground end, and the raised structures 131 make the electromagnetic shielding layer 13 and the adhesive film layer 14 fit tightly, avoiding the separation between the electromagnetic shielding layer 13 and the adhesive film layer 14. In addition, when the amount of glue in the adhesive film layer 14 is insufficient, separation between the shielding film and the printed circuit board will occur. When the amount of glue in the adhesive film layer 14 is too much, it is easy to cause glue overflow at the edge of the printed circuit board. The setting of the raised structures 131 in this embodiment enables the glue overflow lifted by the raised structures 131 to be extruded to the recessed part of the adhesive film layer 14 when the shielding film and the printed circuit board are pressed together, increasing the glue capacity between the electromagnetic shielding layer 13 and the printed circuit board and avoiding the peeling between the shielding film and the printed circuit board.

[0047] It should be noted that in the production process of the above shielding film, the above first film layer 11, contrast structure layer 12, electromagnetic shielding layer 13 and adhesive film layer 14 are all provided on the carrier film. The carrier film supports the above various 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 raised structures 131, and the adhesive film layer 14 is pressed onto the raised structures 131 of the electromagnetic shielding layer 13 to form the basic film material of the shielding film. Thereafter, the basic film material of the shielding film needs to be peeled off from the carrier film, and a hollowed-out pattern of the identification code is ablated on the side of the shielding film away from the adhesive film layer 14.

[0048] Figure 5 It is a schematic structural diagram of another shielding film provided by an embodiment of the present invention. In this embodiment, it is not necessary to roughen the side of the electromagnetic shielding layer 13 close to the adhesive film layer 14. Optionally, a plurality of conductive particles 141 can be provided in the adhesive film layer 14; the conductive particles 141 are used to pierce through the adhesive film layer 14 to connect the ground end of the printed circuit board and the electromagnetic shielding layer 13. Comparison Figure 4 , Figure 5 shows that the adhesive film layer 14 includes a plurality of conductive particles 141, and the conductive particles 141 agglomerate to form larger particles. The larger particles can pierce through the adhesive film layer 14 to establish a connection between the ground end of the printed circuit board and the electromagnetic shielding layer 13. Then, in the manufacturing process of this embodiment, it is not necessary to roughen the electromagnetic shielding layer 13, and the adhesive film layer 14 can be tightly adhered to the electromagnetic shielding layer 13 to form the basic film material of the shielding film.

[0049] In addition, the side of the electromagnetic shielding layer 13 close to the adhesive film layer 14 may be roughened to form a convex structure and then coated with the adhesive film layer 14 having the conductive particles 141. Figure 6 As shown, Figure 6 It is a structural schematic diagram of another shielding film provided by an embodiment of the present invention. In this embodiment, the electromagnetic shielding layer 13 can be roughened to form a protruding structure 131, and a plurality of conductive particles 141 are arranged in the adhesive film layer 14. The conductive particles 141 can pierce the adhesive film layer 14 and electrically connect with the protruding structure 131, thereby further enhancing the conductivity between the electromagnetic shielding layer 14 and the circuit board stratum, and solving the existing problem of delamination between the shielding film and the circuit board due to insufficient adhesive capacity.

[0050] Optional, such as Figure 7 As shown, Figure 7 It is a schematic diagram of the planar structure of an electromagnetic shielding layer provided by an embodiment of the present invention. The electromagnetic shielding layer 13 is provided with a plurality of through holes 132, which is conducive to the exhaust of volatiles from the film layer at high temperature through the through holes 132 of the electromagnetic shielding layer 13, so as to avoid the difficulty in exhausting volatiles from the film layer at high temperature, thereby avoiding bubbling and stratification of the electromagnetic shielding layer 13 causing peeling between the electromagnetic shielding film and the ground layer of the circuit board, thereby ensuring that the electromagnetic shielding film is grounded and the interference charge is discharged.

[0051] Optionally, the through holes 132 may be regularly or irregularly distributed on the electromagnetic shielding layer 13; Figure 7 As shown, the through holes 132 are regularly distributed on the electromagnetic shielding layer 13, which means that the through holes 132 have the same shape and are evenly distributed on the electromagnetic shielding layer 13; the through holes 132 are irregularly distributed on the electromagnetic shielding layer 13, which means that the through holes 132 have different shapes and are randomly distributed on the electromagnetic shielding layer 13. Preferably, as Figure 7 As shown, the shapes of the through holes 132 are the same, and the through holes 132 are evenly distributed on the electromagnetic shielding layer 13. In addition, the through holes 132 can be circular through holes or through holes of any other shape. Figure 7 The through hole 132 is only described as a circular through hole for example, but through holes 132 of any other shapes are within the protection scope of the embodiment of the present invention.

[0052] The shielding films are divided into two types and described in detail below based on the arrangement order of the first film layer 11 and the comparison structure layer 12:

[0053] The first one, continue to refer to Figure 3Optionally, in this embodiment, the contrast structure layer 12 can be provided on the side of the first film layer 11 away from the electromagnetic shielding layer 13; the contrast structure layer 12 forms a hollow pattern of the identification code. 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. Figure 3 As shown, in this embodiment, the material of the contrast structure layer 12 can be a metal, the grayscale value of the color of the metal is less than the grayscale value of the color of the first film layer 11, and the difference is preferably greater than or equal to 10. It should be noted that the above-mentioned metal layer may include at least one of a metal element and a metal alloy, and this embodiment does not limit this. When the contrast structure layer 12 is a metal layer, after the user forms a hollow 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 at a position corresponding to the hollow pattern of the identification code on the insulating film to expose the identification code for user identification, thereby preventing the metal layer from contacting external electronic components and causing a short circuit. In addition, if the above-mentioned insulating film is a colorless and transparent insulating film, the insulating film may not be provided with the above-mentioned opening, and the identification code can also be exposed for user identification.

[0054] Optionally, the contrasting structural layer 12 formed by the metal layer can be a ferrous metal, such as a single metal element such as iron, chromium, or manganese, or an alloy thereof. Exemplary ferrous metals include iron and its alloys, such as steel, pig iron, iron alloys, and cast iron. The grayscale value of the metal layer's color should be sufficiently small to create a clear brightness difference between the metal layer and the first film layer 11. Furthermore, the contrasting structural layer 12 can optionally be an adhesive layer or ink layer having a grayscale value smaller than that of the first film layer 11. Optionally, the contrasting structural layer 12 can be an adhesive layer or ink layer; the contrasting structural layer 12 includes at least one of epoxy resin, rubber, modified epoxy resin, polyimide, polyurethane resin, acrylic resin, modified acrylic resin, polyester, polyphenylene sulfide, polyethylene terephthalate, and liquid crystal polymer. While protecting the electromagnetic shielding layer 13, the contrasting structural layer 12 and the first film layer 11 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 one or a combination of two of a black glue layer, a black ink layer, and a black metal layer. In this embodiment, the contrast structure layer 12 is black glue. In addition to being black metal, it can also be formed by mixing at least one of the above-mentioned epoxy resins, rubbers, modified epoxy resins, polyimides, polyurethane resins, acrylic resins, modified acrylic resins, polyesters, polyphenylene sulfides, polyethylene terephthalates, liquid crystal polymers, and inks with other materials to form black. Then, the gray value of the color of the contrast structure layer 12 is 0, while the color of the first film layer 11 is preferably white, and the gray value of the color of the first film layer 11 is 255. The contrast between black and white is relatively strong, and it is easy to form a clearer identification code. In addition, the contrast structure layer 12 can also be other colors with relatively low gray values, such as dark blue, and this embodiment does not limit this. It should be noted that the contrast structure layer 12 can be a combination material of any two or more of the black glue layer, the black ink layer, and the black metal layer, and this embodiment does not limit this. It should be noted that when the contrast structure layer 12 is provided on the side of the first film layer 11 away from the electromagnetic shielding layer 13, the first film layer 11 can be selected as a colorless glue layer, and the colorless glue layer effectively protects the electromagnetic shielding layer 13 and prevents the electromagnetic shielding layer 13 from being exposed in the hollowed-out pattern. And since the contrast structure layer 12 is black, the electromagnetic shielding layer 13 is exposed through the hollowed-out pattern, and the black of the contrast structure layer 12 also forms a contrast with the color of the electromagnetic shielding layer 13, forming a relatively clear identification code. For example, if the material selected for the electromagnetic shielding layer 13 is copper, the color of the electromagnetic shielding layer 13 is red copper color, and it is easy to distinguish between the red copper color and black. The colorless contrast structure layer 12 effectively protects the copper and prevents it from being oxidized when exposed in the air, so that the color between it and the contrast structure layer 12 is not easily distinguishable later.

[0056] Second, continue to refer to Figure 2 , optionally, the first film layer 11 can be provided on the side of the contrast structure layer 12 away from the electromagnetic shielding layer 13; the first film layer 11 forms a hollowed-out pattern of the identification code. 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, and the gray value of its color is less than the gray value of the color of the first film layer 11. Optionally, the difference in the gray value of its color is greater than or equal to 10.

[0057] Optionally, the contrast structure layer 12 can be an adhesive layer or an ink layer; the contrast structure layer 12 includes at least one of epoxy resin, rubber, modified epoxy resin, polyimide, polyurethane resin, acrylic resin, modified acrylic resin, polyester, polyphenylene sulfide, polyethylene terephthalate, and liquid crystal polymer. In this embodiment, the contrast structure layer 12 can be a black adhesive layer or a black ink layer, so the gray value of the color of the contrast structure layer 12 is 0, while the gray value of the color of the first film layer 11 is preferably 255. The contrast between black and white is relatively strong, and it is easy to form a clearer identification code. In addition, the adhesive layer or the ink layer can also be other colors with relatively low gray values, such as dark blue, dark gray, etc. This embodiment does not limit this.

[0058] Figure 8 It is a schematic structural diagram of another shielding film provided by an embodiment of the present invention. Optionally, when the contrast structure layer 12 is a metal layer, 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 one side of the first film layer 11 close to the electromagnetic shielding layer 13 through a sputtering process; the second metal layer 122 is formed on one side of the first metal layer 121 away from the first film layer 11 through an electroplating process.

[0059] In addition to the limitation of the gray 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 and duller 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. Therefore, in this embodiment, the contrast structure layer 12 can be divided into two layers. That is, first, a first metal layer 121 is formed on the first film layer 11 through a sputtering process. The sputtering process forms a dense and flat metal surface, which is convenient for forming a contrast with the first film layer 11. After that, a second metal layer 122 is formed on the flat first metal layer 121 through an electroplating process. Optionally, the thickness range of the first metal layer 121 can be The thickness range of the second metal layer 122 can be 0.1 μm to 10 μm. Optionally, if the thickness range of the second metal layer 122 is 0.2 μm to 0.4 μm, the resistance value of the second metal layer 122 within a unit area (1 cm x 1 cm) can be set within a range of 15 mΩ to 200 mΩ, and preferably can be set to 30 mΩ.

[0060] In addition, in addition to the sputtering process, the first metal layer 121 can also be formed through other processes, such as one or more of electroless plating, physical vapor deposition, chemical vapor deposition, evaporation plating, sputter plating, electroplating, and mixed plating. This embodiment does not limit the manufacturing process of the first metal layer 121. Optionally, the first metal layer 121 preferably adopts the sputtering process.

[0061] In Figure 8In the illustrated embodiment, when forming the identification code 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. Therefore, the gray value corresponding to the color of the first metal layer 121 is preferably less than the gray value corresponding to the color of the second metal layer 122.

[0062] Figure 9 FIG. is a schematic structural diagram of another shielding film provided by an embodiment of the present invention. Optionally, the first metal layer may 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 less than the gray value of the color of the second sputtered metal layer 1212.

[0063] In this embodiment, two layers of sputtered metal layers can be provided. Because when actually forming the hollow pattern of the identification code by ablating the first film layer 11, the laser energy may penetrate the first sputtered metal layer 1211, the second sputtered metal layer 1212 can be used to increase the guarantee and keep the exposed hollow pattern as a sputtered metal layer with a higher flatness. In addition, the gray value of the color of the first sputtered metal layer 1211 can be set to be less than the gray value of the color of the second sputtered metal layer 1212, and the metal surface of the first sputtered metal layer 1211 can form a distinct color contrast with the light-colored first film layer 11 to improve the clarity of the identification code.

[0064] Figure 10It is a schematic structural diagram of another shielding film provided by an embodiment of the present invention. Optionally, the comparison structure layer 12 may further include a second film layer 15; the second film layer 15 is disposed between the first film layer 11 and the first metal layer 121; the difference between the gray value of the color of the first film layer 11 and the gray value of the color of the second film layer 15 is greater than or equal to a first gray threshold; the first gray threshold is greater than or equal to 10. The second film layer 15 is disposed between the first film layer 11 and the first metal layer 121. When the first metal layer 121 includes a first sputtered metal layer and a second sputtered metal layer, the second film layer 15 is disposed between the first film layer 11 and the first sputtered metal layer, thereby further enhancing the protection of the first metal layer 121. Exemplarily, due to the setting of the second film layer 15, the situation that the laser energy may penetrate the first sputtered metal layer is completely avoided, and the first sputtered metal layer is protected. Then, the gray value of the color of the first film layer 11 also needs to be greater than the gray value of the second film layer 15, and the difference between the gray value of the first film layer 11 and the gray value of the color of the second film layer 15 is preferably greater than or equal to the first gray threshold; the first gray threshold is greater than or equal to 10. Then, the difference between the gray value of the color of the first film layer 11 and the gray value of the color of the second film layer 15 is at least 10, so that a relatively obvious light and 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 for recognizing the identification code formed by the second film layer 15 and the first film layer 11 is improved. Preferably, the above-mentioned first gray threshold may be 50 or 100, which can further increase the light and dark contrast between the second film layer 15 and the first film layer 11, and improve the recognition accuracy and accuracy of the identification code. Optionally, the second film layer 15 may be black; the thickness range of the second film layer 15 may be 0.5 μm to 30 μm. The black second film layer 15 has a strong contrast with the light-colored first film layer 11, and it is easy to form a clearer identification code.

[0065] Based on the above embodiments, an embodiment of the present invention further provides a shielding film. Continuing to refer to Figure 1 , including: a first film layer 11, a comparison structure layer 12, and an electromagnetic shielding layer 13;

[0066] The first film layer 11 is disposed on the first side of the electromagnetic shielding layer 13;

[0067] The comparison structure layer 12 is disposed on the first side of the electromagnetic shielding layer 13;

[0068] Wherein, the gray value of the color of the first film layer 11 is greater than the gray value of the color of the comparison structure layer 12; among the comparison structure layer 12 and the first film layer 11, the layer farther from the electromagnetic shielding layer 13 forms a hollowed-out pattern of the identification code.

[0069] In an embodiment of the present invention, the shielding film includes an electromagnetic shielding layer for shielding electromagnetic interference. A first film layer and a contrast structure layer are provided on a first side of the electromagnetic shielding layer. The first film layer can be disposed between the electromagnetic shielding layer and the contrast structure layer, or the contrast structure layer can be disposed between the electromagnetic shielding layer and the first film layer. The gray value of the color of the first film layer needs to be greater than the gray value of the color of the contrast structure layer, so that a relatively obvious contrast in brightness can be formed between the contrast structure layer and the first film layer. In this embodiment, a hollowed-out pattern of the identification code is formed on the layer of the contrast structure layer and the first film layer that is farther away from the electromagnetic shielding layer. Under the strong contrast in brightness or color between the contrast structure layer and the first film layer, a user can obtain a relatively clear identification code, improving the recognition accuracy and precision of the identification code and facilitating the tracing of the components or electronic products identified by the identification code.

[0070] 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 corresponding identification mark for identifying components or electronic products. The identification code can include character patterns such as numbers and letters, or can be a bar code or a two-dimensional code. The shielding film of this embodiment can include at least one of the above bar code, two-dimensional code, and characters to identify the corresponding components or electronic products. Exemplarily, if the shielding film needs to be attached to a printed circuit board of an electronic device, the identification code of the component can be set at the position corresponding to the component on the shielding film. Multiple identification codes can be provided on the shielding film and are set in one-to-one correspondence with multiple components, thus solving the problem that the printed identification code is not clear due to the lack of a steel plate with sufficient size for setting the identification code in an electronic product, and effectively improving the resolution and recognition accuracy of the identification code. Optionally, the hollowed-out pattern is formed by laser ablation. For example, ultraviolet laser and carbon dioxide laser can be used for laser ablation of the hollowed-out pattern.

[0071] Optionally, in the contrast structure layer and the first film layer, the layer closer to the electromagnetic shielding layer forms a groove pattern; the perpendicular projection of the hollowed-out pattern on the plane where the electromagnetic shielding layer is located completely coincides with the groove pattern. It should be noted that when ablating the above hollowed-out pattern, there may be two situations:

[0072] First, only the layer of the contrast structure layer 12 and the first film layer 11 that is farther away from the electromagnetic shielding layer 13 is burned through to form the hollowed-out pattern of the identification code, and the layer closer to the electromagnetic shielding layer 13 is not ablated. That is, the ablation depth of the hollowed-out pattern is: the thickness of the layer of the contrast structure layer 12 and the first film layer 11 that is farther away from the electromagnetic shielding layer 13. Then the hollowed-out pattern just exposes the structure of the layer closer to the electromagnetic shielding layer 13 that is not etched, and the contrast structure layer 12 and the first film layer 11 form the identification code.

[0073] Second, when forming the hollowed-out pattern of the identification code by burning through one of the contrast structure layer 12 and the first film layer 11 that is farther from the electromagnetic shielding layer 13, partial ablation may be performed on the layer that is closer to the electromagnetic shielding layer 13. In this embodiment, partial ablation is performed on the layer that is closer to the electromagnetic shielding layer 13, rather than complete ablation. After the identification code is ablated, the hollowed-out pattern can also expose the layer of the contrast structure layer 12 and the first film layer 11 that is closer to the electromagnetic shielding layer 13, so that the contrast structure layer 12 and the first film layer 11 form an identification code. Specifically, in the contrast structure layer 12 and the first film layer 11, a groove pattern is formed on the layer that is closer to the electromagnetic shielding layer 13; the vertical projection of the hollowed-out pattern on the plane where the electromagnetic shielding layer 13 is located completely coincides with the groove pattern. The layer of the contrast structure layer 12 and the first film layer 11 that is closer to the electromagnetic shielding layer 13 is partially ablated to form a groove pattern, and because the above groove pattern and the hollowed-out pattern are formed by the same process, the vertical projection of the hollowed-out pattern on the plane where the electromagnetic shielding layer 13 is located completely coincides with the groove pattern.

[0074] Optionally, continue to refer to Figure 3 , 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. In this embodiment, when ablating the contrast structure layer 12 to form the hollowed-out pattern of the identification code, only the contrast structure layer 12 can be ablated, without ablating the first film layer 11; or, when ablating the contrast structure layer 12 to form the hollowed-out 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 hollowed-out pattern on the plane where the electromagnetic shielding layer 13 is located completely coincides with the groove pattern.

[0075] The contrast structure layer 12 is used to form an obvious color or brightness difference with the first film layer 11, and the gray value of the color of the first film layer 11 is greater than the gray value of the color of the contrast structure layer 12. In this embodiment, gray parameters are used to convert the color into a high-quality gray gradient color to detect the contrast of the brightness between the contrast structure layer 12 and the first film layer 11. Gray uses black tones to represent various colors, that is, black is used as the reference color, and different colors are displayed with black of different saturations. The range between black and white is divided into 0 to 255 gray levels. The gray value of white is 255, and the gray value of black is 0. In this embodiment, it is defined that the gray value of the color of the first film layer 11 is greater than the gray value of the color of the contrast structure layer 12. Preferably, the difference between the gray value of the color of the contrast structure layer 12 and the gray value of the color of the first film layer 11 can be defined as relatively large. For example, the color of the first film layer 11 is light yellow, and the gray value of light yellow is relatively large, so the light yellow of the first film layer 11 forms a sharp contrast with the dark color of the contrast structure layer 12.

[0076] Optionally, the difference between the gray value of the color of the first film layer 11 and the gray value of the color of the contrast structure layer 12 is greater than or equal to a first gray threshold; the first gray threshold is greater than or equal to 10. In order to further increase the brightness difference between the contrast structure layer 12 and the first film layer 11, it can be specified that the difference between the gray value of the color of the first film layer 11 and the gray value of the color of the contrast structure layer 12 is greater than or equal to 10 and less than or equal to 255. Then, the difference between the gray value of the color of the first film layer 11 and the gray value of the color of the contrast structure layer 12 is at least 10, so as to form a relatively obvious light and dark difference between the contrast structure layer 12 and the first film layer 11, and improve the recognition accuracy of the identification code formed by the contrast structure layer 12 and the first film layer 11 by the identification code recognition device.

[0077] In order to further increase the brightness difference between the contrast structure layer 12 and the first film layer 11, the above-mentioned first gray threshold can be specified as 50. Then, the difference between the gray value of the color of the first film layer 11 and the gray value of the color of the contrast structure layer 12 is at least 50. The color brightness of the first film layer 11 is stronger, and the color brightness of the contrast structure layer 12 is smaller, further increasing the light and dark contrast between the contrast structure layer 12 and the first film layer 11, and improving the recognition accuracy and accuracy of the identification code. On the basis of the above-mentioned embodiment, in this embodiment, the first gray threshold can be further specified as 100. Then, the difference between the gray value of the color of the first film layer 11 and the gray value of the color of the contrast structure layer 12 is at least 100.

[0078] In this embodiment, the material of the first film layer 11 can be an adhesive layer or an ink layer. Optionally, the first film layer 11 can include at least one of modified epoxy resins, modified acrylics, modified rubbers, modified thermoplastic polyimides, modified polyesters, thermoplastic resins, thermosetting resins, and pressure-sensitive adhesives. In this implementation, at least one of the above materials is mixed with other materials to form a light color with a relatively high gray value. The first film layer 11 is preferably a color with a relatively high gray value. For example, white, or a color with a gray value closer to white such as light gray. The specific color of the first film layer 11 is not limited in this embodiment. Preferably, the first film layer 11 can be a white adhesive layer or a white ink layer.

[0079] 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 setting order of the contrast structure layer 12 and the first film layer 11 can be changed. For example, as Figure 2 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 shown, 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 on each other to form a distinct contrast. Regardless of whether the contrast structure layer 12 and the first film layer 11 are Figure 1 in the setting order of Figure 3The setting order in the figure is that the outermost layer is used to form a hollow pattern of the identification code, and the color of the other layer exposed by the hollow pattern can form a large brightness difference with the outermost layer, making the identification code clearer and easier for users to accurately identify. Figure 2 As shown, when the first film layer 11 is arranged at the outermost side, a hollow pattern of the identification code needs to be formed on the first film layer 11. The hollow pattern of the first film layer 11 exposes the darker (lower brightness) contrast structure layer 12, forming a clearer identification code. Figure 3 As shown, when contrasting structural layer 12 is disposed on the outermost side, a hollow pattern of an identification code is formed on contrasting structural layer 12. The hollow pattern on contrasting structural layer 12 exposes the lighter-colored first film layer 11, forming a clear identification code. Alternatively, the hollow pattern can be formed by laser ablation, for example, using an ultraviolet laser or a carbon dioxide laser.

[0080] The shielding films are divided into two types and described in detail below based on the arrangement order of the first film layer 11 and the comparison structure layer 12:

[0081] The first one, continue to refer to Figure 3 Optionally, in this embodiment, the contrast structure layer 12 can be provided on the side of the first film layer 11 away from the electromagnetic shielding layer 13; the contrast structure layer 12 forms a hollow pattern of the identification code. 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. Figure 3 As shown, in this embodiment, the material of the contrast structure layer 12 can be a metal, the grayscale value of the color of the metal is less than the grayscale value of the color of the first film layer 11, and the difference is preferably greater than or equal to 10. It should be noted that the above-mentioned metal layer may include at least one of a metal element and a metal alloy, and this embodiment does not limit this. When the contrast structure layer 12 is a metal layer, after the user forms a hollow 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 at a position corresponding to the hollow pattern of the identification code on the insulating film to expose the identification code for user identification, thereby preventing the metal layer from contacting external electronic components and causing a short circuit. In addition, if the above-mentioned insulating film is a colorless and transparent insulating film, the insulating film may not be provided with the above-mentioned opening, and the identification code can also be exposed for user identification.

[0082] Optionally, the contrast structure layer 12 formed by the metal layer can be a ferrous metal, for example, elemental metals such as iron, chromium or manganese, or their alloys. Exemplarily, ferrous metals such as iron and its alloys like steel, pig iron, ferroalloys, cast iron, etc. The gray value of the color of the metal layer needs to be small enough so that there is an obvious brightness difference between the metal layer and the first film layer 11. In addition, optionally, the contrast structure layer 12 can be an adhesive layer or an ink layer with a gray value smaller than that of the first film layer 11. Optionally, the contrast structure layer 12 can be an adhesive layer or an ink layer; the contrast structure layer 12 includes at least one of epoxy resin, rubber, modified epoxy resin, polyimide, polyurethane resin, acrylic resin, modified acrylic resin, polyester, polyphenylene sulfide, polyethylene terephthalate glycolic acid, and liquid crystal polymer. While protecting the electromagnetic shielding layer 13, the contrast structure layer 12 and the first film layer 11 form a clear identification code. In this embodiment, the above-mentioned adhesive layer can be a thermosetting adhesive.

[0083] Optionally, the contrast structure layer 12 can be a combination of one or two of a black adhesive layer, a black ink layer, and a black metal layer. In this embodiment, the contrast structure layer 12 is a black adhesive. In addition to being a ferrous metal, it can also be formed by mixing at least one of the above-mentioned epoxy resin, rubber, modified epoxy resin, polyimide, polyurethane resin, acrylic resin, modified acrylic resin, polyester, polyphenylene sulfide, polyethylene terephthalate glycolic acid, liquid crystal polymer, and ink with other materials to form black. Then the gray value of the color of the contrast structure layer 12 is 0, while the color of the first film layer 11 is preferably white, and the gray value of the color of the first film layer 11 is 255. The contrast between black and white is relatively strong, and it is easy to form a clearer identification code. In addition, the contrast structure layer 12 can also be other colors with a relatively low gray value, such as dark blue. This embodiment does not limit this. It should be noted that the contrast structure layer 12 can be a combination of any two or more of a black adhesive layer, a black ink layer, and a black metal layer. This embodiment does not limit this. It should be noted that when the contrast structure layer 12 is disposed on the side of the first film layer 11 away from the electromagnetic shielding layer 13, the first film layer 11 can be selected as a colorless adhesive layer. The colorless adhesive layer effectively protects the electromagnetic shielding layer 13 and prevents the electromagnetic shielding layer 13 from being exposed in the hollow pattern. And since the contrast structure layer 12 is black, the electromagnetic shielding layer 13 is exposed through the hollow pattern. The black of the contrast structure layer 12 also forms a contrast with the color of the electromagnetic shielding layer 13, forming a relatively clear identification code. For example, if the material selected for the electromagnetic shielding layer 13 is copper, the color of the electromagnetic shielding layer 13 is red copper color, which is easy to distinguish from black. The colorless contrast structure layer 12 effectively protects the copper and prevents it from being oxidized when exposed in the air, making it difficult to distinguish the color between the subsequent contrast structure layer 12.

[0084] Second, continue to refer to Figure 2, Optionally, the first film layer 11 can be disposed on the side of the contrast structure layer 12 away from the electromagnetic shielding layer 13; the first film layer 11 forms a hollowed-out pattern of the identification code. Optionally, the contrast structure layer 12 can be one or a combination of two or more of an adhesive layer, an ink layer, and a metal layer, and the grayscale value of its color is less than the grayscale value of the color of the first film layer 11. Optionally, the difference in the grayscale values of its colors is greater than or equal to 10.

[0085] , Optionally, the contrast structure layer 12 can be an adhesive layer or an ink layer; the contrast structure layer 12 includes at least one of epoxy resin, rubber, modified epoxy resin, polyimide, polyurethane resin, acrylic resin, modified acrylic resin, polyester, polyphenylene sulfide, polyethylene terephthalate, and liquid crystal polymer. In this embodiment, the contrast structure layer 12 can be a black adhesive layer or a black ink layer, then the grayscale value of the color of the contrast structure layer 12 is 0, while the grayscale value of the color of the first film layer 11 is preferably 255, and the contrast between black and white is relatively strong, which is easy to form a clearer identification code. In addition, the adhesive layer or the ink layer can also be other colors with relatively low grayscale values such as dark blue and dark gray, and this embodiment does not limit this.

[0086] Based on the same concept, an embodiment of the present invention further provides a circuit board, as Figure 11 shown, Figure 11 is a schematic structural diagram of a circuit board provided by an embodiment of the present invention. The circuit board includes a printed circuit board 2 and the shielding film 1 provided by any embodiment of the present invention; a glue film layer is disposed on the side of the electromagnetic shielding layer of the shielding film 1 away from the first film layer; the glue film layer side of the shielding film 1 is attached to the printed circuit board 2. The circuit board in this embodiment includes the technical features of the shielding film provided by any embodiment of the present invention and has the beneficial effects of the shielding film provided by any embodiment of the present invention.

[0087] A large number of components with different functions are integrated on the printed circuit board 2. In this embodiment, the identification code of the component can be set at the position corresponding to the component on the shielding film 1. The shielding film 1 can entirely cover the above-mentioned printed circuit board to achieve overall electromagnetic shielding. The shielding film 1 can also include multiple smaller sub-shielding films, and each sub-shielding film is used to cover the corresponding area of the printed circuit board, and this embodiment does not limit this. In addition, the identification code of the electronic device where the circuit board is located can also be set on the shielding film 1. Exemplarily, the identification code of the electronic device can be set in the edge area of the shielding film 1.

[0088] An embodiment of the present invention further provides an electronic device. Figure 12 is a schematic structural diagram of an electronic device provided by an embodiment of the present invention, as Figure 12 shown. The electronic device provided by an embodiment of the present invention includes the circuit board 3 of any embodiment of the present invention. The electronic device can be such as Figure 12The mobile phone shown in the figure may also be a computer, a television, a smart wearable device, etc., and this embodiment does not make special limitations thereto.

[0089] Note that the above is only a preferred embodiment of the present invention and the technical principles applied. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein. Various obvious changes, re-adjustments, and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the concept of the present invention, more other equivalent embodiments can be included, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A shielding film, characterized in that: include: a first film layer, a contrasting structural layer, and an electromagnetic shielding layer; The first film layer is arranged on a first side of the electromagnetic shielding layer; The contrast structure layer is arranged on the first side of the electromagnetic shielding layer; The grayscale value of the color of the first film layer is greater than the grayscale value of the color of the contrast structure layer; and the layer of the contrast structure layer and the first film layer that is farther from the electromagnetic shielding layer forms a hollow pattern of the identification code; The first film layer is arranged on a side of the contrast structure layer away from the electromagnetic shielding layer; The contrast structure layer includes 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 away from the first film layer; the grayscale value of the color of the first metal layer is smaller than the grayscale value of the color of the second metal layer.

2. The shielding film according to claim 1, wherein Also includes: Adhesive film layer; The adhesive film layer is arranged on a side of the electromagnetic shielding layer away from the first film layer.

3. The shielding film according to claim 1, wherein A difference between a grayscale value of the color of the first film layer and a grayscale value of the color of the contrast structure layer is greater than or equal to a first grayscale threshold; and the first grayscale threshold is greater than or equal to 10.

4. The shielding film according to claim 3, wherein The first grayscale threshold is 50.

5. The shielding film according to claim 3, wherein The first grayscale threshold is 100. The shielding film according to claim 1 , wherein: The first film layer is a glue layer or an ink layer; The material of the first film layer includes at least one of modified epoxy resins, modified acrylic resins, modified rubber resins, modified thermoplastic polyimides, modified polyesters, thermoplastic resins, thermosetting resins, and pressure-sensitive adhesives.

7. The shielding film according to claim 1, 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.

8. The shielding film according to claim 7, wherein The contrast structure layer is a glue layer or an ink layer; The contrast structural layer includes at least one of epoxy resin, rubber, modified epoxy resin, polyimide, polyurethane resin, acrylic resin, modified acrylic resin, polyester, polyphenylene sulfide, polyethylene terephthalate and liquid crystal polymer.

9. The shielding film according to claim 1, wherein The first film layer is arranged on a side of the contrast structure layer away from the electromagnetic shielding layer; The contrast structure layer is a metal layer, and the first film layer is a colorless adhesive layer.

10. The shielding film according to claim 1, wherein The electromagnetic shielding layer is provided with a plurality of through holes.

11. The shielding film according to claim 2, wherein The electromagnetic shielding layer is roughened on one side close to the adhesive film layer to form a plurality of protrusions; the protrusions are used to pierce the adhesive film layer and connect to the ground terminal of the printed circuit board; or, A plurality of conductive particles are provided in the adhesive film layer; the conductive particles are used to pierce the adhesive film layer to connect the ground terminal of the printed circuit board and the electromagnetic shielding layer; or, The side of the electromagnetic shielding layer close to the film layer is roughened to form a plurality of protruding structures. The film layer is provided with a plurality of conductive particles. The protruding structures and the conductive particles together pierce the film layer and are connected to the ground terminal of the printed circuit board.

12. The shielding film according to claim 1, wherein Among the contrast structure layer and the first film layer, the layer closer 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 completely overlaps with the groove pattern.

13. A circuit board, characterized in that: include: A printed circuit board and a shielding film according to any one of claims 1 to 12; wherein a glue film layer is provided on a side of the electromagnetic shielding layer of the shielding film away from the first film layer; One side of the adhesive film layer of the shielding film is attached to the printed circuit board.

Images