A shielding film and a circuit board

Abstract

The present invention discloses a shielding film and a circuit board. The shielding film includes an insulating layer and an electromagnetic shielding layer. The insulating layer is disposed on one side of the electromagnetic shielding layer. Among them, the gray value of the color of the insulating layer is less than the gray value of the color of the electromagnetic shielding layer. The present invention provides a shielding film and a circuit board to realize the setting of identification codes on the screen film, thereby improving the clarity and resolution of the identification codes.

Description

Technical Field

[0001] The present invention relates to the field of electronic technology, and particularly 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 the internal components of mobile phones becoming rapidly high-frequency and high-speed 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 previous technology was to print the identification code (such as a two-dimensional code) on a steel plate, but due to the thinness and lightness of electronic products, the size of the steel plate was 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, but due to the small size of the flexible board, the printed identification code is not clear, the accuracy cannot meet the identification requirements, and 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: an insulating layer and an electromagnetic shielding layer;

[0007] The insulating layer is disposed on one side of the electromagnetic shielding layer;

[0008] Wherein, the gray value of the color of the insulating layer is less than the gray value of the color of the electromagnetic shielding layer.

[0009] Second aspect, an embodiment of the present invention provides a shielding film, including: an insulating layer and an electromagnetic shielding layer;

[0010] The insulating layer is disposed on one side of the electromagnetic shielding layer;

[0011] Wherein, the gray value of the color of the insulating layer is less than the gray value of the color of the electromagnetic shielding layer; the insulating layer forms a hollowed-out pattern of an identification code.

[0012] Third aspect, an embodiment of the present invention further provides a circuit board, which includes a printed circuit board and the shielding film provided in any embodiment of the present invention; a glue film layer is disposed on the side of the electromagnetic shielding layer of the shielding film away from the insulating layer;

[0013] One side of the glue film layer of the shielding film is attached to the printed circuit board.

[0014] In the present invention, the shielding film includes an electromagnetic shielding layer for shielding electromagnetic interference. An insulating layer is disposed on one side of the electromagnetic shielding layer. The gray value of the color of the electromagnetic shielding layer needs to be greater than the gray value of the color of the insulating layer, so that a relatively obvious contrast in brightness and darkness can be formed between the electromagnetic shielding layer and the insulating layer. In this embodiment, a hollowed-out pattern of an identification code can be formed in the insulating layer, so that under the strong contrast in brightness or color between the electromagnetic shielding layer and the insulating layer, the user can obtain an identification code with higher clarity, improving the recognition accuracy and precision of the identification code, and facilitating the traceability of the components or electronic products identified by the identification code. Description of the Drawings

[0015] Figure 1 is a schematic structural diagram of a shielding film provided by an embodiment of the present invention;

[0016] Figure 2 is a schematic structural diagram of another shielding film provided by an embodiment of the present invention;

[0017] Figure 3 is a schematic structural diagram of another shielding film provided by an embodiment of the present invention;

[0018] Figure 4 is a schematic structural diagram of another shielding film provided by an embodiment of the present invention;

[0019] Figure 5 is a schematic structural diagram of another shielding film provided by an embodiment of the present invention;

[0020] Figure 6 is a schematic plan view of an electromagnetic shielding layer provided by an embodiment of the present invention;

[0021] Figure 7 is a schematic structural diagram of a circuit board provided by an embodiment of the present invention;

[0022] Figure 8 It is a schematic structural diagram of an electronic device provided by an embodiment of the present invention. Specific embodiments

[0023] 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 convenience of description, only the parts related to the present invention rather than all the structures are shown in the drawings.

[0024] With the development of flexible printed circuit boards, an important index for evaluating the performance of flexible printed 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, have become increasingly 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 identification codes due to the size specifications of electronic products, the embodiments of the present invention creatively set the identification codes on the shielding film to improve the clarity and resolution of the identification codes.

[0025] Specifically, an embodiment of the present invention provides a shielding film, including: an insulating layer and an electromagnetic shielding layer;

[0026] The insulating layer is provided on one side of the electromagnetic shielding layer;

[0027] Wherein, the gray value of the color of the insulating layer is less than the gray value of the color of the electromagnetic shielding layer.

[0028] In the embodiments of the present invention, for the gray value of the color of the electromagnetic shielding layer to be greater than the gray value of the color of the insulating layer, as long as the device can recognize the colors of the two and further process them to form a clear and distinguishable identification code after forming the identification code, there is no limitation on how much greater the gray value of the color of the electromagnetic shielding layer should be than the gray value of the color of the insulating layer.

[0029] In the embodiments of the present invention, the shielding film includes an electromagnetic shielding layer for shielding electromagnetic interference. An insulating layer is provided on one side of the electromagnetic shielding layer. The gray value of the color of the electromagnetic shielding layer needs to be greater than the gray value of the color of the insulating layer, so that a relatively obvious contrast in brightness between light and dark can be formed between the electromagnetic shielding layer and the insulating layer. In this embodiment, a hollowed-out pattern of the identification code can be formed in the insulating layer, so that under the strong contrast in light and dark or color between the electromagnetic shielding layer and the insulating layer, users can obtain an identification code with higher clarity, improving the recognition accuracy and precision of the identification code, and facilitating the traceability of the components or electronic products identified by the identification code.

[0030] 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 of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0031] 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 an insulating layer 11 and an electromagnetic shielding layer 12. Among them, the material of the electromagnetic shielding layer 12 is a conductive material with good shielding performance, which is electrically connected to the grounding end on the circuit board, and can effectively achieve electromagnetic interference shielding of electronic devices on the circuit board. The insulating layer 11 is arranged away from the circuit board, which can avoid the contact between the electromagnetic shielding layer 12 and external electronic components, effectively prevent the occurrence of short circuits, and protect the electromagnetic shielding layer 12.

[0032] In this embodiment, the gray value of the color of the electromagnetic shielding layer 12 is greater than the gray value of the color of the insulating layer 11. The electromagnetic shielding layer 12 is used to form an obvious color or brightness difference with the insulating layer 11, and the gray value of the color of the electromagnetic shielding layer 12 is greater than the gray value of the color of the insulating layer 11. In this embodiment, gray parameters are used to convert a color into a high-quality gray gradient color to detect the contrast of the brightness between the insulating layer 11 and the electromagnetic shielding layer 12. 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 electromagnetic shielding layer 12 is greater than the gray value of the color of the insulating layer 11. Then, if a hollowed-out pattern of an identification code is formed on the insulating layer 11, the light and dark contrast between the electromagnetic shielding layer 12 and the insulating layer 11 can form a clear and easily recognizable identification code, improving the recognition accuracy and accuracy of the user for the identification code. Optionally, the above-mentioned hollowed-out pattern of the identification code can be formed by laser ablation. For example, ultraviolet laser and carbon dioxide laser can be used for laser ablation of the hollowed-out pattern.

[0033] Figure 2It is a schematic structural diagram of another shielding film provided by an embodiment of the present invention. Optionally, the film of this embodiment may further include: an adhesive film layer 13; the adhesive film layer 13 is disposed on the side of the electromagnetic shielding layer 12 away from the insulating layer 11 for connecting the electromagnetic shielding layer 12 to the circuit board. The insulating layer 11 of the above shielding film is used to form a hollowed-out pattern of an identification code for users to identify. In this embodiment, the adhesive film layer 13 can be disposed on the side of the electromagnetic shielding layer 12 away from the insulating layer 11 to fix the position of the above shielding film without affecting the exposure of the identification code. Optionally, the adhesive film layer 13 in this embodiment may include at least one of a thermosetting adhesive and a thermoplastic adhesive. A thermosetting adhesive is a type of adhesive that forms chemical bonds under the sole action or combined action of a thermal catalyst. After curing, the thermosetting adhesive does not melt or dissolve. Specifically, the thermosetting adhesive in this embodiment may include at least one of phenol formaldehyde, urea formaldehyde, melamine, epoxy, polyurethane, acrylate, unsaturated polyester, and silicone. Optionally, the adhesive film layer 13 can be white or colorless, etc. The specific color of the adhesive film layer 13 is not limited in this embodiment. This embodiment can achieve the pasting and fixing of the shielding film to the circuit board or other structures through the adhesive film layer 13.

[0034] Optionally, the difference between the gray value of the color of the electromagnetic shielding layer 12 and the gray value of the color of the insulating layer 11 is greater than or equal to a 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 electromagnetic shielding layer 12 and the gray value of the color of the insulating layer 11 is at least 10, so that a relatively obvious light and dark difference is formed between the electromagnetic shielding layer 12 and the insulating layer 11, improving the accuracy of the identification of the identification code formed by the electromagnetic shielding layer 12 and the insulating layer 11 by the identification device.

[0035] In order to further increase the brightness difference between the electromagnetic shielding layer 12 and the insulating layer 11, the first gray threshold can be defined as 50, then the difference between the gray value of the color of the electromagnetic shielding layer 12 and the gray value of the color of the insulating layer 11 is at least 50. The color brightness of the electromagnetic shielding layer 12 is stronger, and the color brightness of the insulating layer 11 is smaller, further increasing the light and dark contrast between the electromagnetic shielding layer 12 and the insulating layer 11 and improving the identification accuracy and precision of the identification code.

[0036] Based on the above embodiments, in this embodiment, the first gray threshold may be further defined as 100. Then, the difference between the gray value of the color of the electromagnetic shielding layer 12 and the gray value of the color of the insulating layer 11 is at least 100. For example, if the gray value of the color of the insulating layer 11 is 0, the difference between the gray value of the color of the electromagnetic shielding layer 12 and the gray value of the color of the insulating layer 11 is at least 100, and even 255. Then, the gray value of the electromagnetic shielding layer 12 can be selected to be greater than or equal to 100. When the gray value difference is 255, one of the electromagnetic shielding layer 12 and the insulating 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.

[0037] In this embodiment, relative to the electromagnetic shielding layer 12, the insulating layer 11 is a film layer with a darker color. For example, it can be black, or a color closer to black in gray value such as dark blue. The specific color of the insulating layer 11 is not limited in this embodiment. Optionally, the insulating layer 11 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, at least one of the above materials is mixed with other materials to form a dark color with a lower gray value. Optionally, the color of the insulating layer 11 can be black; the insulating layer 11 can be at least one of a black adhesive layer and black ink. The black adhesive layer has a good water vapor barrier effect, and the black ink has a strong flame retardant effect. The insulating layer 11 can be set as a black adhesive layer or a black ink layer. In addition, the insulating layer 11 can include both black adhesive material and black ink.

[0038] Optionally, the material of the electromagnetic shielding layer 12 can include at least one of copper, aluminum, nickel, titanium, chromium, and silver. That is, the electromagnetic shielding layer 12 can be one of copper, aluminum, nickel, titanium, chromium, and silver, or an alloy formed by at least two of copper, aluminum, nickel, titanium, chromium, and silver. This embodiment does not limit this. For example, the material of the electromagnetic shielding layer 12 can be copper, which has good electrical properties, high shielding performance, high transmission quality, and good reliability while ensuring a low cost. And the copper of the electromagnetic shielding layer 12 is red (with a higher brightness), and its brightness is greater than that of the insulating layer 11, so a relatively obvious light and dark difference is formed between the electromagnetic shielding layer 12 and the insulating layer 11, enhancing the clarity of the identification code.

[0039] It should be noted that in this embodiment, the shielding film is attached to the printed circuit board through the side provided with the adhesive film layer 13, which is used to quickly conduct the interference signals generated by the electronic device from the electromagnetic shielding layer 12 to the ground plane or ground wire of the printed circuit board. Figure 3FIG. 0 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 12 close to the adhesive film layer 13 can be roughened to form a plurality of protruding structures 121; the protruding structures 121 are used to pierce the adhesive film layer 13 and connect to the grounding end of the printed circuit board. The protruding structures 121 can realize the connection between the electromagnetic shielding layer 12 and the grounding end, and the protruding structures 121 make the electromagnetic shielding layer 12 and the adhesive film layer 13 fit tightly, avoiding the separation between the electromagnetic shielding layer 12 and the adhesive film layer 13. In addition, when the amount of glue in the adhesive film layer 13 is insufficient, separation between the shielding film and the printed circuit board will occur. When the amount of glue in the adhesive film layer 13 is too much, it is easy to cause glue overflow at the edge of the printed circuit board. The arrangement of the protruding structures 121 in this embodiment enables the overflow glue lifted by the protruding structures 121 to be extruded into the concave part of the adhesive film layer 13 when the shielding film and the printed circuit board are pressed together, increasing the glue capacity between the electromagnetic shielding layer 12 and the printed circuit board and avoiding the peeling between the shielding film and the printed circuit board.

[0040] It should be noted that in the production process of the above shielding film, the above insulating layer 11, electromagnetic shielding layer 12, and adhesive film layer 13 are all provided on the carrier film. The carrier film supports the above-mentioned various film layers. After the insulating layer 11 and the electromagnetic shielding layer 12 are formed on the carrier film, the electromagnetic shielding layer 12 is roughened to form the protruding structures 121, and the adhesive film layer 13 is pressed onto the protruding structures 121 of the electromagnetic shielding layer 12 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 13.

[0041] Figure 4 FIG. 7 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 12 close to the adhesive film layer 13. Optionally, a plurality of conductive particles 131 can be provided in the adhesive film layer 13; the conductive particles 131 are used to pierce the adhesive film layer 13 to connect the grounding end of the printed circuit board and the electromagnetic shielding layer 12. Compare Figure 3 , Figure 4 shows that the adhesive film layer 13 includes a plurality of conductive particles 131, and the conductive particles 131 agglomerate to form larger particles. The larger particles can pierce the adhesive film layer 13 to establish a connection between the grounding end of the printed circuit board and the electromagnetic shielding layer 12. Then, in the manufacturing process of this embodiment, it is not necessary to roughen the electromagnetic shielding layer 12, and the adhesive film layer 13 can be tightly attached to the electromagnetic shielding layer 12 to form the basic film material of the shielding film.

[0042] In addition, it is also possible to roughen the side of the electromagnetic shielding layer 12 close to the adhesive film layer 13 to form protruding structures first and then coat the adhesive film layer 13 with conductive particles 131, as Figure 5 shown, Figure 5FIG. 0 is a schematic structural view of another shielding film provided by an embodiment of the present invention. In this embodiment, while roughening the electromagnetic shielding layer 12 to form a convex structure 121, a plurality of conductive particles 131 are provided in the adhesive film layer 13. The conductive particles 131 can pierce through the adhesive film layer 13 to be electrically connected to the convex structure 121, thereby further enhancing the electrical conductivity between the electromagnetic shielding layer 14 and the circuit board ground layer, and solving the problem of delamination between the shielding film and the circuit board caused by insufficient adhesive volume in the prior art.

[0043] Optionally, as Figure 6 shown, Figure 6 FIG. 7 is a schematic plan view of an electromagnetic shielding layer provided by an embodiment of the present invention. The electromagnetic shielding layer 12 is provided with a plurality of through holes 122, which is beneficial for the volatiles in the adhesive film layer to exhaust through the through holes 122 of the electromagnetic shielding layer 12 at high temperature, so as to avoid the difficulty of exhausting the volatiles in the adhesive film layer at high temperature, thereby avoiding the peeling between the electromagnetic shielding layer 12 and the circuit board ground layer caused by blistering and delamination of the electromagnetic shielding layer 12, and further ensuring that the electromagnetic shielding film is grounded and the interference charges are conducted out.

[0044] Optionally, the through holes 122 can be distributed regularly or irregularly on the electromagnetic shielding layer 12; among them, as Figure 6 shown, the through holes 122 are regularly distributed on the electromagnetic shielding layer 12, which means that each through hole 122 has the same shape and is evenly distributed on the electromagnetic shielding layer 12; the through holes 122 are irregularly distributed on the electromagnetic shielding layer 12, which means that the shapes of each through hole 122 are different and are disorderly distributed on the electromagnetic shielding layer 12. Preferably, as Figure 6 shown, each through hole 122 has the same shape, and each through hole 122 is evenly distributed on the electromagnetic shielding layer 12. In addition, the through hole 122 can be a circular through hole, or any other shape of through hole. Figure 6 Only taking the through hole 122 as a circular through hole as an example for illustration, but any other shape of through hole 122 is within the protection scope of the embodiment of the present invention.

[0045] Continuing to refer to Figure 1 , an embodiment of the present invention further provides a shielding film, including: an insulating layer 11 and an electromagnetic shielding layer 12;

[0046] The insulating layer 11 is disposed on one side of the electromagnetic shielding layer 12;

[0047] Wherein, the gray value of the color of the insulating layer 11 is less than the gray value of the color of the electromagnetic shielding layer 12; the insulating layer 11 forms a hollowed-out graphic of an identification code.

[0048] In an embodiment of the present invention, the shielding film includes an electromagnetic shielding layer for shielding electromagnetic interference. An insulating layer is provided on one side of the electromagnetic shielding layer. The gray value of the color of the electromagnetic shielding layer needs to be greater than the gray value of the color of the insulating layer, so that a relatively obvious contrast in brightness can be formed between the electromagnetic shielding layer and the insulating layer. In this embodiment, a hollowed-out pattern of the identification code can be formed in the insulating layer, so that under the strong contrast in brightness or color between the electromagnetic shielding layer and the insulating layer, the 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.

[0049] Optionally, the identification code may 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 may include character graphics such as numbers and letters, or may be a bar code or a two-dimensional code. The film in this embodiment may include at least one of the above bar code, two-dimensional code, and characters to identify the corresponding components or electronic products. Exemplarily, the film may be attached to the printed circuit board of an electronic device, and then the identification code of the component may be set at the position corresponding to the component on the film. Multiple identification codes may be set on the film and correspond to multiple 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 in the 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.

[0050] It should be noted that there may be two situations when ablating the above hollowed-out pattern:

[0051] First, only the insulating layer 11 is burned through to form the hollowed-out pattern of the identification code, and the electromagnetic shielding layer 12 is not ablated. That is, the ablation depth of the hollowed-out pattern is: the thickness of the insulating layer 11. Then the hollowed-out pattern just exposes the unablated electromagnetic shielding layer 12, and the insulating layer 11 and the electromagnetic shielding layer 12 form the identification code.

[0052] Second, when forming the hollowed-out pattern of the identification code by burning through the insulating layer 11, the electromagnetic shielding layer 12 may be partially ablated. In this embodiment, the electromagnetic shielding layer 12 is partially ablated instead of being completely ablated. After the ablation of the identification code is completed, the hollowed-out pattern can also expose the structure of the electromagnetic shielding layer 12, so that the electromagnetic shielding layer 12 and the insulating layer 11 form an identification code. Specifically, a groove pattern is formed on the side of the electromagnetic shielding layer 12 close to the insulating layer 11; the vertical projection of the hollowed-out pattern of the insulating layer 11 on the plane where the electromagnetic shielding layer 12 is located completely coincides with the groove pattern. A part of the electromagnetic shielding layer 12 is 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 12 is located completely coincides with the groove pattern.

[0053] In this embodiment, the gray value of the color of the electromagnetic shielding layer 12 is greater than the gray value of the color of the insulating layer 11. The electromagnetic shielding layer 12 is used to form an obvious color or brightness difference with the insulating layer 11, and the gray value of the color of the electromagnetic shielding layer 12 is greater than the gray value of the color of the insulating layer 11. This embodiment uses gray parameters to convert a color into a high-quality gray gradient color to detect the contrast of the brightness between the insulating layer 11 and the electromagnetic shielding layer 12. 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 electromagnetic shielding layer 12 is greater than the gray value of the color of the insulating layer 11. Then, if a hollowed-out pattern of the identification code is formed on the insulating layer 11, the light and dark contrast between the electromagnetic shielding layer 12 and the insulating layer 11 can form a clear and easily recognizable identification code, improving the recognition accuracy and accuracy of the user for the identification code. Optionally, the hollowed-out pattern of the above identification code can be formed by laser ablation. For example, ultraviolet laser and carbon dioxide laser can be used for ablation of the hollowed-out pattern.

[0054] Optionally, the difference between the gray value of the color of the electromagnetic shielding layer 12 and the gray value of the color of the insulating layer 11 is greater than or equal to a first gray threshold; the first gray threshold is greater than or equal to 10, so the difference between the gray value of the color of the electromagnetic shielding layer 12 and the gray value of the color of the insulating layer 11 is at least 10, making a relatively obvious light and dark difference between the electromagnetic shielding layer 12 and the insulating layer 11, and improving the recognition accuracy of the identification code formed by the electromagnetic shielding layer 12 and the insulating layer 11 by the identification code recognition device.

[0055] In order to further increase the brightness difference between the electromagnetic shielding layer 12 and the insulating layer 11, the first gray threshold can be defined as 50. Then, the difference between the gray value of the color of the electromagnetic shielding layer 12 and the gray value of the color of the insulating layer 11 is at least 50. The color of the electromagnetic shielding layer 12 has a stronger brightness, and the color of the insulating layer 11 has a smaller brightness, further increasing the contrast between light and dark between the electromagnetic shielding layer 12 and the insulating layer 11, and improving the recognition accuracy and precision of the identification code.

[0056] 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 electromagnetic shielding layer 12 and the gray value of the color of the insulating layer 11 is at least 100. For example, if the gray value of the color of the insulating layer 11 is 0, the gray value of the color of the electromagnetic shielding layer 12 and the gray value of the color of the insulating layer 11 differ by at least 100, and even differ by 255. Then, the gray value of the electromagnetic shielding layer 12 can be selected to be greater than or equal to 100. The case where the gray values differ by 255 is that one of the electromagnetic shielding layer 12 and the insulating layer 11 is pure black and the other is pure white, that is, one of the gray values is 255 and the other is 0, and the difference in brightness or color is large, further enhancing the clarity of the identification code.

[0057] In this embodiment, relative to the electromagnetic shielding layer 12, the insulating layer 11 is a film layer with a darker color. For example, it can be black, or a color closer to black such as dark blue. The specific color of the insulating layer 11 is not limited in this embodiment. Optionally, the insulating layer 11 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. In this embodiment, at least one of the above materials is mixed with other materials to form a darker color with a lower gray value. Optionally, the color of the insulating layer 11 can be black; the insulating layer 11 can be at least one of a black glue layer and black ink. The black glue layer has a good water vapor barrier effect, and the black ink has a strong flame retardant effect. The insulating layer 11 can be set as a black glue layer or a black ink layer. In addition, the insulating layer 11 can include both black glue and black ink at the same time.

[0058] Optionally, the material of the electromagnetic shielding layer 12 may include at least one of copper, aluminum, nickel, titanium, chromium, and silver. That is, the electromagnetic shielding layer 12 may be one of copper, aluminum, nickel, titanium, chromium, and silver, or may be an alloy formed by at least two of copper, aluminum, nickel, titanium, chromium, and silver. This embodiment does not limit this. For example, the material of the electromagnetic shielding layer 12 may be copper, which has good electrical characteristics, high shielding performance, high transmission quality, and good reliability while ensuring a low cost. And the copper of the electromagnetic shielding layer 12 is red (with a higher brightness), and its brightness is greater than that of the insulating layer 11, so a relatively obvious light and dark difference is formed between the electromagnetic shielding layer 12 and the insulating layer 11, enhancing the clarity of the identification code.

[0059] Based on the same concept, an embodiment of the present invention further provides a circuit board, as Figure 7 shown, Figure 7 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 a shielding film 1 provided by any embodiment of the present invention; a glue film layer is provided on the side of the electromagnetic shielding layer of the shielding film 1 away from the first film layer; one side of the glue film layer 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.

[0060] A large number of components with different functions are integrated on the printed circuit board 2. In this embodiment, identification codes of the components may be provided at positions corresponding to the components on the shielding film 1. The shielding film 1 may entirely cover the above-mentioned printed circuit board to achieve overall electromagnetic shielding. The shielding film 1 may also include multiple smaller sub-shielding films, and each sub-shielding film is used to cover the corresponding area of the printed circuit board. This embodiment does not limit this. In addition, the identification code of the electronic device where the circuit board is located may also be provided on the shielding film 1. Exemplarily, the identification code of the electronic device may be provided in the edge area of the shielding film 1.

[0061] An embodiment of the present invention further provides an electronic device. Figure 8 is a schematic structural diagram of an electronic device provided by an embodiment of the present invention, as Figure 8 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 may be a mobile phone as shown in Figure 8 , or may be a computer, a television, a smart wearable device, etc. This embodiment does not make special limitations on this.

[0062] 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, and 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, Comprising: An insulating layer and an electromagnetic shielding layer; The insulating layer is disposed on one side of the electromagnetic shielding layer; Wherein, the gray value of the color of the insulating layer is less than the gray value of the color of the electromagnetic shielding layer; the insulating layer forms a hollowed-out graphic of an identification code; The difference between the gray value of the color of the electromagnetic shielding layer and the gray value of the color of the insulating layer is greater than or equal to a first gray threshold, and the first gray threshold is greater than or equal to 10.

2. The shielding film according to claim 1, wherein Further comprising: An adhesive film layer; The adhesive film layer is disposed on the side of the electromagnetic shielding layer away from the insulating layer.

3. The shielding film according to claim 1, wherein, The first gray threshold is 50.

4. The shielding film according to claim 1, characterized in that, The first gray threshold is 100.

5. The shielding film according to claim 1, characterized in that, The insulating layer comprises 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.

6. The shielding film according to claim 5, characterized in that, The insulating layer is at least one of a black ink layer and a black adhesive layer.

7. The shielding film according to claim 1, wherein The material of the electromagnetic shielding layer comprises at least one of copper, aluminum, nickel, titanium, chromium, and silver.

8. The shielding film according to claim 2, characterized in that, The side of the electromagnetic shielding layer close to the adhesive film layer is roughened to form a plurality of convex structures; The convex structures are used to pierce the adhesive film layer and connect to the ground terminal of the printed circuit board.

9. The shielding film according to claim 2 or 8, characterized in that, A plurality of conductive particles are disposed 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.

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 1, wherein The side of the electromagnetic shielding layer close to the insulating layer forms a groove graphic, and the vertical projection of the hollowed-out graphic of the insulating layer on the plane where the electromagnetic shielding layer is located completely coincides with the groove graphic.

12. A circuit board, characterized in that, Comprising: A printed circuit board and a shielding film as described in any one of claims 1-11; a adhesive film layer is disposed on the side of the electromagnetic shielding layer of the shielding film away from the insulating layer; The side of the adhesive film layer of the shielding film is attached to the printed circuit board.

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