CN110691498B - Electromagnetic shielding film, circuit board and preparation method of electromagnetic shielding film - Google Patents

Electromagnetic shielding film, circuit board and preparation method of electromagnetic shielding film Download PDF

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Publication number
CN110691498B
CN110691498B CN201810743106.9A CN201810743106A CN110691498B CN 110691498 B CN110691498 B CN 110691498B CN 201810743106 A CN201810743106 A CN 201810743106A CN 110691498 B CN110691498 B CN 110691498B
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layer
shielding
film
shielding layer
film layer
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CN110691498A (en
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苏陟
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Guangzhou Fangbang Electronics Co Ltd
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Guangzhou Fangbang Electronics Co Ltd
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K9/00—Screening of apparatus or components against electric or magnetic fields
    • H05K9/0073—Shielding materials
    • H05K9/0081—Electromagnetic shielding materials, e.g. EMI, RFI shielding
    • H05K9/0084—Electromagnetic shielding materials, e.g. EMI, RFI shielding comprising a single continuous metallic layer on an electrically insulating supporting structure, e.g. metal foil, film, plating coating, electro-deposition, vapour-deposition
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B3/00—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form; Layered products having particular features of form
    • B32B3/02—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form; Layered products having particular features of form characterised by features of form at particular places, e.g. in edge regions
    • B32B3/08—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form; Layered products having particular features of form characterised by features of form at particular places, e.g. in edge regions characterised by added members at particular parts
    • B32B3/085—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form; Layered products having particular features of form characterised by features of form at particular places, e.g. in edge regions characterised by added members at particular parts spaced apart pieces on the surface of a layer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B3/00—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form; Layered products having particular features of form
    • B32B3/26—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form; Layered products having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer
    • B32B3/266—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form; Layered products having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer characterised by an apertured layer, the apertures going through the whole thickness of the layer, e.g. expanded metal, perforated layer, slit layer regular cells B32B3/12
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B33/00—Layered products characterised by particular properties or particular surface features, e.g. particular surface coatings; Layered products designed for particular purposes not covered by another single class
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/04—Interconnection of layers
    • B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/20—Adhesives in the form of films or foils characterised by their carriers
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J9/00—Adhesives characterised by their physical nature or the effects produced, e.g. glue sticks
    • C09J9/02—Electrically-conducting adhesives
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K1/00—Printed circuits
    • H05K1/02—Details
    • H05K1/0213—Electrical arrangements not otherwise provided for
    • H05K1/0216—Reduction of cross-talk, noise or electromagnetic interference
    • H05K1/0218—Reduction of cross-talk, noise or electromagnetic interference by printed shielding conductors, ground planes or power plane
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/20—Properties of the layers or laminate having particular electrical or magnetic properties, e.g. piezoelectric
    • B32B2307/212—Electromagnetic interference shielding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2457/00—Electrical equipment
    • B32B2457/08—PCBs, i.e. printed circuit boards
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2301/00—Additional features of adhesives in the form of films or foils
    • C09J2301/10—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet
    • C09J2301/12—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet by the arrangement of layers
    • C09J2301/122—Additional features of adhesives in the form of films or foils characterized by the structural features of the adhesive tape or sheet by the arrangement of layers the adhesive layer being present only on one side of the carrier, e.g. single-sided adhesive tape
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
    • H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
    • H05K2201/07—Electric details
    • H05K2201/0707—Shielding
    • H05K2201/0715—Shielding provided by an outer layer of PCB

Abstract

The invention relates to the technical field of electronics, and discloses an electromagnetic shielding film, a circuit board and a preparation method of the electromagnetic shielding film, wherein the electromagnetic shielding film comprises a shielding layer and a film layer, the film layer is arranged on the shielding layer, one surface of the shielding layer, which is close to the film layer, is a non-flat surface, and through holes penetrating through the upper surface and the lower surface of the shielding layer are arranged on the shielding layer, so that the exhaust of volatile matters in the film layer through the through holes at high temperature is facilitated, the difficult exhaust of volatile matters in the film layer at high temperature is avoided, the stripping between the electromagnetic shielding film and the stratum of the circuit board caused by foaming and layering of the electromagnetic shielding film is avoided, and the grounding of the electromagnetic shielding film and the derivation of interference charges are further ensured; in addition, the non-flat surface of the shielding layer pierces the adhesive film layer and is connected with the stratum of the circuit board when the electromagnetic shielding film is pressed with the circuit board, and meanwhile, the adhesive substance is extruded to the concave position of the non-flat surface to increase the adhesive containing amount, so that the board explosion phenomenon is not easy to occur, and the stratum connection of the shielding layer and the circuit board is ensured.

Description

Electromagnetic shielding film, circuit board and preparation method of electromagnetic shielding film
Technical Field
The invention relates to the technical field of electronics, in particular to an electromagnetic shielding film, a circuit board and a preparation method of the electromagnetic shielding film.
Background
With the rapid development of the electronic industry, electronic products further develop toward miniaturization, light weight and high-density assembly, and the development of flexible circuit boards is greatly promoted, so that the integration of element devices and wire connection is realized. The flexible circuit board can be widely applied to industries such as mobile phones, liquid crystal displays, communication, aerospace and the like.
Under the push of the international market, functional flexible circuit boards are dominant in the flexible circuit board market, and an important index for evaluating the performance of functional flexible circuit boards is electromagnetic Shielding (Electromagnetic Interference Shielding, abbreviated as EMI Shielding). With the integration of functions of communication devices such as mobile phones, internal components thereof are rapidly increased in frequency and speed. For example: in addition to the original audio transmission function, the camera function has become a necessary function, and the WLAN (Wireless Local Area Networks, wireless local area network), GPS (Global Positioning System ) and internet function have become popular, and the trend of rapid high frequency and high speed of the components is more unavoidable in addition to the integration of the future sensing components. Electromagnetic interference, signal attenuation during transmission, insertion loss and jitter problems inside and outside the component caused by high frequency and high speed driving are becoming serious.
At present, the electromagnetic shielding film commonly used by the existing circuit board comprises a shielding layer and a conductive adhesive layer, and the shielding layer is in contact conduction with the stratum of the circuit board through the conductive adhesive layer. However, in carrying out the present invention, the inventors have found that there are at least the following problems in the prior art: volatile matters exist in the conductive adhesive layer under the high-temperature condition, but the shielding layer is compact, the volatile matters are difficult to discharge, and then the shielding film is foamed and layered to cause stripping between the electromagnetic shielding film and the stratum of the circuit board, so that the grounding failure is caused, and the interference charge cannot be led out.
Disclosure of Invention
The embodiment of the invention aims to provide an electromagnetic shielding film, a circuit board and a preparation method of the electromagnetic shielding film, which can effectively prevent volatile matters in a conductive adhesive layer in the traditional electromagnetic shielding film from being unable to be discharged through a compact shielding layer at high temperature, so that peeling between the electromagnetic shielding film and a stratum of the circuit board caused by bubbling and layering of the electromagnetic shielding film can be avoided, the grounding of the electromagnetic shielding film is ensured, and interference charges are led out.
In order to solve the technical problems, the invention provides an electromagnetic shielding film, which comprises a shielding layer and a film layer, wherein the film layer is arranged on the shielding layer; the shielding layer is provided with a through hole penetrating through the upper surface and the lower surface of the shielding layer.
Preferably, the surface of the shielding layer, which is close to the adhesive film layer, comprises a plurality of protrusions and a plurality of concave portions, and the protrusions and the concave portions are arranged at intervals.
Preferably, the shielding layer is provided with convex conductor particles on one surface close to the adhesive film layer.
Preferably, the height of the conductor particles is 0.1 μm to 30 μm.
Preferably, the thickness of the shielding layer is 0.1 μm-45 μm, and the thickness of the adhesive film layer is 1 μm-80 μm.
Preferably, the adhesive film layer comprises an adhesive layer containing conductive particles; or, the adhesive film layer comprises an adhesive layer without conductive particles.
Preferably, the electromagnetic shielding film further comprises a protective film layer, and the protective film layer is arranged on one surface, far away from the adhesive film layer, of the shielding layer.
Preferably, the area of the through hole is 0.1 μm 2 -1mm 2 。
Preferably, the number of the through holes in the shielding layer is 10-1000 per square centimeter.
In order to solve the same technical problems, the embodiment of the invention also provides a circuit board, which comprises a circuit board body and the electromagnetic shielding film, wherein the electromagnetic shielding film is pressed with the circuit board body through the adhesive film layer, and the shielding layer pierces the adhesive film layer and is electrically connected with the stratum of the circuit board body.
The embodiment of the invention provides an electromagnetic shielding film and a circuit board, wherein the electromagnetic shielding film comprises a shielding layer and a film layer, the film layer is arranged on the shielding layer, one surface of the shielding layer, which is close to the film layer, is a non-flat surface, and through holes penetrating through the upper surface and the lower surface of the shielding layer are arranged on the shielding layer, so that the exhaust of volatile matters in the film layer through the through holes of the shielding layer at high temperature is facilitated, the difficult exhaust of volatile matters in the film layer at high temperature is avoided, the stripping between the electromagnetic shielding film and a stratum of the circuit board caused by foaming and layering of the electromagnetic shielding film is avoided, and the grounding of the electromagnetic shielding film and the derivation of interference charges are further ensured; in addition, the non-flat surface of the shielding layer pierces the adhesive film layer and is connected with the stratum of the circuit board when the electromagnetic shielding film is pressed with the circuit board, so that the stratum connection of the shielding layer and the circuit board is ensured, the grounding of the electromagnetic shielding film is further ensured, and interference charges are led out; in addition, because the shielding layer is the non-flat surface near the one side of glued membrane layer, consequently when electromagnetic shield membrane and circuit board are pressed, constitute glued class material of glued membrane layer and be extruded in this non-flat surface's concave position to increase hold the volume of gluing, thereby be difficult to appear exploding the board phenomenon, avoided current electromagnetic shield membrane because hold the volume of gluing not enough and lead to the problem of high temperature exploding the board, and then guaranteed electromagnetic shield membrane ground connection effectively, thereby derive the interference charge.
In order to solve the same technical problems, the embodiment of the invention also provides a preparation method of the electromagnetic shielding film, which comprises the following steps:
forming a shielding layer; one surface of the shielding layer is a non-flat surface, and a through hole penetrating through the upper surface and the lower surface of the shielding layer is formed in the shielding layer;
and forming a glue film layer on the non-flat surface of the shielding layer.
As a preferred scheme, the preparation method of the electromagnetic shielding film further comprises the following steps:
and forming a protective film layer on one surface of the shielding layer, which is far away from the adhesive film layer.
Preferably, the forming the shielding layer specifically includes:
forming a protective film layer on the carrier film;
forming a shielding layer on the protective film layer; or alternatively, the first and second heat exchangers may be,
forming a shielding layer on the surface of the strippable layer with the carrier;
forming a protective film layer on the shielding layer;
the peelable layer of the tape carrier is peeled off.
Preferably, after forming the shielding layer, the method further includes:
convex conductor particles are formed on the non-planar surface of the shielding layer.
As a preferred scheme, a glue film layer is formed on the non-flat surface of the shielding layer, specifically:
coating a glue film layer on the release film;
pressing and transferring the adhesive film layer onto the non-flat surface of the shielding layer; or alternatively, the first and second heat exchangers may be,
and coating a glue film layer on the non-flat surface of the shielding layer.
The embodiment of the invention provides a preparation method of an electromagnetic shielding film, which comprises the steps of firstly, forming a shielding layer; wherein, one surface of the shielding layer is a non-flat surface, and a through hole penetrating through the upper surface and the lower surface of the shielding layer is formed on the shielding layer; then, forming a glue film layer on the uneven surface of the shielding layer, so that the prepared electromagnetic shielding film comprises the shielding layer and the glue film layer, wherein the glue film layer is arranged on the shielding layer, one surface of the shielding layer, which is close to the glue film layer, is an uneven surface, and through holes penetrating through the upper surface and the lower surface of the shielding layer are formed in the shielding layer, so that volatile matters in the glue film layer can be exhausted through the through holes of the shielding layer at high temperature, the phenomenon that the volatile matters in the glue film layer are difficult to exhaust at high temperature is avoided, the situation that the electromagnetic shielding film is peeled from the stratum of the circuit board due to foaming layering of the electromagnetic shielding film is avoided, and the grounding of the electromagnetic shielding film is ensured, and interference charges are led out; in addition, the non-flat surface of the shielding layer pierces the adhesive film layer and is connected with the stratum of the circuit board when the electromagnetic shielding film is pressed with the circuit board, so that the stratum connection of the shielding layer and the circuit board is ensured, the grounding of the electromagnetic shielding film is further ensured, and interference charges are led out; in addition, because the shielding layer is the non-flat surface near the one side of glued membrane layer, consequently when electromagnetic shield membrane and circuit board are pressed, constitute glued class material of glued membrane layer and be extruded in this non-flat surface's concave position to increase hold the volume of gluing, thereby be difficult to appear exploding the board phenomenon, avoided current electromagnetic shield membrane because hold the volume of gluing not enough and lead to the problem of high temperature exploding the board, and then guaranteed electromagnetic shield membrane ground connection effectively, thereby derive the interference charge.
Drawings
Fig. 1 is a schematic structural view of an electromagnetic shielding film in an embodiment of the present invention;
FIG. 2 is a schematic view of another angle of the electromagnetic shielding film in an embodiment of the present invention;
FIG. 3 is a schematic view of the structure of another implementation of the electromagnetic shielding film in an embodiment of the present invention;
fig. 4 is a schematic structural view of a circuit board according to an embodiment of the present invention;
FIG. 5 is a schematic flow chart of a method for preparing an electromagnetic shielding film according to an embodiment of the invention;
wherein, 1, shielding layer; 11. a through hole; 12. a convex portion; 13. a recessed portion; 2. an adhesive film layer; 3. conductor particles; 4. a protective film layer; 6. a circuit board body.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 1 to 4, an electromagnetic shielding film according to a preferred embodiment of the present invention includes a shielding layer 1 and a film layer 2, wherein the film layer 2 is disposed on the shielding layer 1; one surface of the shielding layer 1, which is close to the adhesive film layer 2, is a non-flat surface, and a through hole 11 penetrating through the upper surface and the lower surface of the shielding layer 1 is formed in the shielding layer 1.
In the embodiment of the invention, the adhesive film layer 2 is arranged on the shielding layer 1, one surface of the shielding layer 1, which is close to the adhesive film layer 2, is a non-flat surface, and the shielding layer 1 is provided with the through holes 11 penetrating through the upper surface and the lower surface of the shielding layer, so that the exhaust of volatile matters in the adhesive film layer 2 through the through holes 11 of the shielding layer 1 at high temperature is facilitated, the difficult exhaust of volatile matters in the adhesive film layer 2 at high temperature is avoided, the stripping between the electromagnetic shielding film and the stratum of the circuit board caused by foaming and layering of the electromagnetic shielding film is avoided, and the grounding of the electromagnetic shielding film and the derivation of interference charges are further ensured; in addition, the non-flat surface of the shielding layer 1 pierces the adhesive film layer 2 and is connected with the stratum of the circuit board when the electromagnetic shielding film is pressed with the circuit board, so that the stratum connection of the shielding layer 1 and the circuit board is ensured, the grounding of the electromagnetic shielding film is further ensured, and interference charges are led out; in addition, because the one side of shielding layer 1 near glued membrane layer 2 is the non-flat surface, consequently when electromagnetic shielding film and circuit board are pressed, constitute glued class material of glued membrane layer 2 and be extruded in this non-flat surface's concave position to increase hold the volume of gluing, thereby be difficult to appear exploding the board phenomenon, avoided current electromagnetic shielding film because hold the volume of gluing not enough and lead to the problem of high temperature exploding the board, and then guaranteed electromagnetic shielding film ground connection effectively, thereby derive the interference charge.
In the embodiment of the present invention, the non-planar surface of the shielding layer 1 is a regular non-planar surface or an irregular non-planar surface. Specifically, when the uneven surface of the shielding layer 1 is a regular uneven surface, the uneven surface is a periodically undulating structure, and the amplitude of the undulation and the interval of the undulation on the uneven surface are the same; when the uneven surface of the shielding layer 1 is an irregular uneven surface, the uneven surface is in a structure with non-periodic fluctuation, and the amplitude of fluctuation and/or the interval of fluctuation on the uneven surface are different.
As shown in fig. 1 to 4, in order to make the shielding layer 1 easier to pierce through the adhesive film layer 2 during the lamination process, a surface of the shielding layer 1 near the adhesive film layer 2 in this embodiment includes a plurality of protrusions 12 and a plurality of recesses 13, and the plurality of protrusions 12 and the plurality of recesses 13 are disposed at intervals. The shielding layer 1 is provided with the plurality of convex parts 12 and the plurality of concave parts 13 on one surface close to the adhesive film layer 2, and the plurality of convex parts 12 and the plurality of concave parts 13 are arranged at intervals, so that the shielding layer 1 is easier to pierce the adhesive film layer 2 in the lamination process, and the reliability of connection between the shielding layer 1 and the stratum of the circuit board is ensured; in addition, when the electromagnetic shielding film is pressed with the circuit board, the glue substance forming the glue film layer 2 is extruded into the concave part 13 to increase the glue containing amount, so that the board explosion phenomenon is not easy to occur, the problem that the existing electromagnetic shielding film explodes the board at high temperature due to insufficient glue containing amount is avoided, and the grounding of the electromagnetic shielding film is effectively ensured, so that the interference charge is led out. In addition, the plurality of protruding portions 12 may be spaced apart from the outer surface of the adhesive film layer 2, or may contact with the outer surface of the adhesive film layer 2 or extend out of the outer surface of the adhesive film layer 2.
In the embodiment of the present invention, in order to further secure the reliability of the grounding while improving the conduction efficiency, the pitch between each of the convex portions 12 and the adjacent concave portion 13 in the present embodiment is the same. By setting the interval between each of the convex portions 12 and the adjacent concave portion 13 to be the same, the conductor particles 3 on the convex portion 12 can uniformly pierce the adhesive film layer 2, thereby further ensuring the reliability of connection between the shielding layer 1 and the ground layer of the circuit board, while improving the conduction efficiency. Preferably, each of the projections 12 has the same shape; the shape of each concave part 13 is the same; wherein each convex part 12 has an axisymmetric structure; each concave part 13 has an axisymmetric structure; of course, each of the convex portions 12 may be a non-axisymmetric structure, and each of the concave portions 13 may be a non-axisymmetric structure. Because the distance between each convex part 12 and the adjacent concave part 13 is the same, and the shape of each convex part 12 is the same, the shape of each concave part 13 is the same, so that the glue containing amount on the surface of the shielding layer 1 is uniform, the explosion plate is further avoided, the grounding of the electromagnetic shielding film is further ensured, and the interference charge is led out.
As shown in fig. 3 and 4, in order to further ensure the electrical connection between the electromagnetic shielding film and the ground layer of the circuit board, the shielding layer 1 in this embodiment is provided with convex conductor particles 3 on a surface close to the adhesive film layer 2. Convex conductor particles 3 are arranged on one surface of the shielding layer 1, which is close to the adhesive film layer 2, so that the adhesive film layer 2 is conveniently penetrated, and the electromagnetic shielding film is further ensured to be electrically connected with the stratum of the circuit board. Preferably, the conductor particles 3 are intensively distributed on the convex portions 11, so that the shielding layer 1 is easier to pierce through the adhesive film layer 2 in the pressing process, thereby realizing grounding and improving the quality of electromagnetic shielding.
In the embodiment of the present invention, the conductor particles 3 may include a plurality of conductor particles 3, and the plurality of conductor particles 3 may be regularly or irregularly distributed on one surface of the shielding layer 1 near the adhesive film layer 2; wherein, the regular distribution of the plurality of conductor particles 3 on the surface of the shielding layer 1 near the adhesive film layer 2 means that the plurality of conductor particles 3 have the same shape and are uniformly distributed on the surface of the shielding layer 1 near the adhesive film layer 2; the plurality of conductor particles 3 being irregularly distributed on the surface of the shielding layer 1 near the adhesive film layer 2 means that the plurality of conductor particles 3 are irregularly and randomly distributed on the surface of the shielding layer 1 near the adhesive film layer 2. Preferably, the shapes of the plurality of conductor particles 3 are the same, and the plurality of conductor particles 3 are uniformly distributed on one surface of the shielding layer 1 close to the adhesive film layer 2.
In an implementation, the shielding layer 1 may be formed first, and then the conductor particles 3 may be formed on the shielding layer 1 through other processes. Of course, the shielding layer 1 and the conductor particles 3 may also be of a unitary structure formed by a one-shot molding process.
Preferably, the height of the conductor particles 3 is 0.1 μm to 30 μm; the conductor particles 3 may be spaced from the outer surface of the adhesive film layer 2, or may contact the outer surface of the adhesive film layer 2 or extend out of the outer surface of the adhesive film layer 2. In addition, the outer surface of the adhesive film layer 2 may be a flat surface without undulation, or may be an uneven surface with gentle undulation. In addition, the surface of the shielding layer 1 away from the adhesive film layer 2 may be any shape, for example, a flat surface, a non-flat surface with a wavy shape, or other rough surface. The drawings only illustrate the case where the side of the shielding layer 1 away from the adhesive film layer 2 is a flat surface, but any other shape is within the scope of the present invention.
It should be noted that the shapes of the conductor particles 3 in fig. 3 and 4 are merely exemplary, and the conductor particles 3 may be in other shapes such as clusters, ice-hanging shapes, stalactites, dendrites, etc. due to differences in process means and parameters. In addition, the conductor particles 3 in the embodiment of the present invention are not limited to the shape shown in the drawings and described above, and any conductor particles 3 having piercing and conducting functions are within the scope of the present invention.
Preferably, the thickness of the shielding layer 1 is 0.1 μm-45 μm, and the thickness of the adhesive film layer 2 is 1 μm-80 μm. The adhesive film layer 2 is made of the following materials: modified epoxy resins, acrylic, modified rubbers, and modified thermoplastic polyimides. It will be appreciated that, in order to ensure good electrical conductivity of the shielding layer 1, the shielding layer 1 includes one or more of a metal shielding layer, a carbon nanotube shielding layer, a ferrite shielding layer, and a graphene shielding layer. Wherein the metal shielding layer comprises a single metal shielding layer and/or an alloy shielding layer; wherein the single metal shielding layer is made of any one material of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver and gold, and the alloy shielding layer 1 is made of any two or more materials of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver and gold.
It should be noted that, the shielding layer 1 in this embodiment may have a single-layer structure or a multi-layer structure; when the shielding layers 1 are multiple layers, each shielding layer 1 may be provided with protruding conductor particles 3 or no protruding conductor particles 3 on a surface close to the adhesive film layer 2. The adhesive film layer 2 can be of a single-layer structure or a multi-layer structure; the shielding layer 1 and the adhesive film layer 2 may be provided in plurality. Preferably, when the number of the shielding layer 1 and the adhesive film layer 2 is plural, the shielding layer 1 and the adhesive film layer 2 are sequentially arranged at intervals, for example, when the number of the shielding layer 1 and the adhesive film layer 2 is plural, the arrangement sequence may be that: one of the shielding layers 1, one of the adhesive film layers 2, the other of the shielding layers 1, the other of the adhesive film layers 2, and the like, and no further description is given here; in addition, the shielding layer 1 of the present embodiment may be configured to be foamed, etc., according to the actual production and application requirements, and will not be described in detail herein.
Preferably, the waviness of the surface of the shielding layer 1 near the adhesive film layer 2 (i.e. the distance between the highest point and the lowest point of the surface of the shielding layer 1 near the adhesive film layer 2) is 0.1 μm-30 μm, and the waviness of the surface of the shielding layer 1 near the adhesive film layer 2 is set within the above range, so as to enhance the penetrating function of the shielding layer 1, thereby ensuring that the interference charges in the shielding layer 1 are smoothly introduced into the ground, and further avoiding the accumulation of the interference charges to form an interference source.
Preferably, the sum of the thickness of the adhesive film layer 2 and the height of the conductor particles 3 and the waviness of the surface of the shielding layer 1 close to the adhesive film layer 2 satisfy the proportional relationship of 0.5-2 so as to ensure sufficient penetration strength and adhesive capacity, which is specifically expressed as follows: on the one hand, the phenomenon that the sum of the fluctuation of the thickness of the adhesive film layer 2 relative to the surface of the shielding layer 1 close to the adhesive film layer 2 and the height of the conductor particles 3 is too small to cause the explosion of the board due to insufficient adhesive holding capacity is prevented, and on the other hand, the phenomenon that the sum of the fluctuation of the thickness of the shielding layer 1 close to the surface of the adhesive film layer 2 and the height of the conductor particles 3 relative to the thickness of the adhesive film layer 2 is too small to cause the grounding failure due to insufficient puncture strength is prevented.
In the embodiment of the present invention, the conductor particles 3 include one or more of metal particles, carbon nanotube particles, and ferrite particles. Further, the metal particles include single metal particles and/or alloy particles; wherein the single metal particles are made of any one material of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver and gold, and the alloy particles are made of any two or more materials of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver and gold. The conductor particles 3 may be the same as or different from the material of the shielding layer 1.
In the embodiment of the present invention, in order to further secure the connection of the electromagnetic shielding film to the ground, the adhesive film layer 2 in the embodiment includes an adhesive layer containing conductive particles. The adhesive layer 2 comprises an adhesive layer containing conductive particles so as to improve the conductivity of the adhesive layer 2, thereby further ensuring the connection of the electromagnetic shielding film with the ground. Of course, the adhesive film layer 2 may include an adhesive layer without conductive particles to reduce eddy current loss of the circuit board with the electromagnetic shielding film, thereby ensuring the integrity of transmission and improving the bending property of the circuit board while improving shielding effectiveness.
The conductive particles may be conductive particles separated from each other or large-particle conductive particles agglomerated; when the conductive particles are mutually separated conductive particles, the ground conductivity of the adhesive film layer 2 can be further improved; and when the conductive particles are large-particle conductive particles formed by agglomeration, the piercing strength can be increased.
As shown in fig. 3 and 4, the electromagnetic shielding film of the present embodiment further includes a protective film layer 4, where the protective film layer 4 is disposed on a surface of the shielding layer 1 away from the adhesive film layer 2. Since the protective film layer 4 has an insulating effect, the shielding effectiveness of the shielding layer 1 is ensured; in addition, the protective film layer 4 also has a protective function to ensure that the shielding layer 1 is not scratched and damaged in the use process, so that the high shielding effectiveness of the shielding layer 1 is maintained. The protective film layer 4 comprises a PPS film layer, a PEN film layer, a polyester film layer, a polyimide film layer, a film layer formed by curing epoxy resin ink, a film layer formed by curing polyurethane ink, a film layer formed by curing modified acrylic resin or a film layer formed by curing polyimide resin. The surface of the protective film layer 4, which is far away from the shielding layer 1, can be further provided with a carrier film, and the carrier film plays a supporting role on the protective film layer 4, so that the subsequent processing is facilitated. In addition, the protective film layer 4 and the adhesive film layer 2 can be closely contacted through the through holes 11 after being pressed or printed, so that the peeling strength between the protective film layer 4 and the shielding layer 1 can be effectively improved, namely, peeling is not easy to occur between the protective film layer 4 and the shielding layer 1.
In the embodiment of the present invention, the area of the through hole 11 is preferably 0.1 μm 2 -1mm 2 . By making the area of the through hole 11 preferably 0.1 μm 2 -1mm 2 To ensure that the volatile substances of the adhesive film layer 2 can pass through the adhesive film layer with enough size at high temperatureThe through holes 11 are used for exhausting, so that the phenomenon that volatile matters in the adhesive film layer 2 are difficult to exhaust at high temperature is avoided, and further, the electromagnetic shielding film is prevented from being peeled off from the stratum of the circuit board due to foaming and layering of the electromagnetic shielding film, so that the electromagnetic shielding film is grounded, and interference charges are led out. Preferably, the number of the through holes 11 in the shielding layer 1 is 10-1000 per square centimeter. The number of the through holes 11 in the shielding layer 1 is 10-1000 per square centimeter, so that the fact that the volatile matters in the adhesive film layer 2 can be exhausted through enough through holes 11 at high temperature is ensured, the phenomenon that the electromagnetic shielding film is peeled off from the stratum of the circuit board due to foaming and layering of the electromagnetic shielding film caused by difficult exhaust of the volatile matters in the adhesive film layer 2 at high temperature is avoided, and the fact that the electromagnetic shielding film is grounded and interference charges are led out is ensured.
In the embodiment of the present invention, the through holes 11 may be regularly or irregularly distributed on the shielding layer 1; wherein, the through holes 11 are regularly distributed on the shielding layer 1, which means that the through holes 11 are uniformly distributed on the shielding layer 1 and have the same shape; the irregularly distributed through holes 11 on the shielding layer 1 means that the through holes 11 are irregularly and randomly distributed on the shielding layer 1. Preferably, the shape of each through hole 11 is the same, and each through hole 11 is uniformly distributed on the shielding layer 1. In addition, the through hole 11 may be a circular through hole, or may be any other through hole, and the drawings only illustrate that the through hole 11 is a circular through hole, but any other through hole 11 is within the scope of the present invention.
Referring to fig. 4, in order to solve the same technical problems, the embodiment of the invention further provides a circuit board, which comprises a circuit board body 6 and the electromagnetic shielding film, wherein the electromagnetic shielding film is pressed with the circuit board body 6 through the adhesive film layer 2, and the shielding layer 1 pierces through the adhesive film layer 2 and is electrically connected with the stratum of the circuit board body 6.
In the embodiment of the invention, the shielding layer 1 can pierce the adhesive film layer 2 and be connected with the stratum of the circuit board body 6 when the electromagnetic shielding film is pressed with the circuit board body 6, so that the stratum connection of the shielding layer 1 and the circuit board body 6 is ensured, the interference charge in the shielding layer 1 is led into the ground, and the influence of an interference source formed by the accumulation of the interference charge on the normal operation of the circuit board is avoided.
Preferably, the circuit board body 6 is one of flexible single-sided, flexible double-sided, flexible multi-layer board and rigid-flex board.
Referring to fig. 5, in order to solve the same technical problem, an embodiment of the present invention further provides a method for preparing an electromagnetic shielding film, including the following steps:
s11, forming a shielding layer 1; wherein, one surface of the shielding layer 1 is a non-flat surface, and a through hole 11 penetrating through the upper surface and the lower surface of the shielding layer 1 is formed on the shielding layer 1;
s12, forming a glue film layer 2 on the non-flat surface of the shielding layer 1.
In the embodiment of the present invention, the area of the through hole 11 is preferably 0.1 μm 2 -1mm 2 . By making the area of the through hole 11 preferably 0.1 μm 2 -1mm 2 The volatile matters in the adhesive film layer 2 can be exhausted through the through holes 11 which are large enough at high temperature, so that the problem that the volatile matters in the adhesive film layer 2 are difficult to exhaust at high temperature is avoided, and further, the stripping between the electromagnetic shielding film and the stratum of the circuit board caused by foaming and layering of the electromagnetic shielding film is avoided, so that the grounding of the electromagnetic shielding film is ensured, and the interference charges are led out. Preferably, the number of the through holes 11 in the shielding layer 1 is 10-1000 per square centimeter. The number of the through holes 11 in the shielding layer 1 is 10-1000 per square centimeter, so that the fact that the volatile matters in the adhesive film layer 2 can be exhausted through enough through holes 11 at high temperature is ensured, the phenomenon that the electromagnetic shielding film is peeled off from the stratum of the circuit board due to foaming and layering of the electromagnetic shielding film caused by difficult exhaust of the volatile matters in the adhesive film layer 2 at high temperature is avoided, and the fact that the electromagnetic shielding film is grounded and interference charges are led out is ensured.
In the embodiment of the present invention, the through holes 11 may be regularly or irregularly distributed on the shielding layer 1; wherein, the through holes 11 are regularly distributed on the shielding layer 1, which means that the through holes 11 are uniformly distributed on the shielding layer 1 and have the same shape; the irregularly distributed through holes 11 on the shielding layer 1 means that the through holes 11 are irregularly and randomly distributed on the shielding layer 1. Preferably, the shape of each through hole 11 is the same, and each through hole 11 is uniformly distributed on the shielding layer 1. In addition, the through hole 11 may be a circular through hole, or may be another irregularly shaped through hole.
As shown in fig. 1 to 4, in order to make the shielding layer 1 easier to pierce through the adhesive film layer 2 during the lamination process, the surface of the shielding layer 1 near the adhesive film layer 2 in this embodiment includes a plurality of protrusions 12 and a plurality of recesses 13, where a plurality of the protrusions 12 and a plurality of the recesses 13 are spaced apart, and the conductor particles 3 are intensively distributed on the protrusions 12. The shielding layer 1 is provided with the plurality of convex parts 12 and the plurality of concave parts 13 on one surface close to the adhesive film layer 2, and the plurality of convex parts 12 and the plurality of concave parts 13 are arranged at intervals, so that the conductor particles 3 are intensively distributed on the convex parts 12, and the shielding layer 1 is easier to pierce through the adhesive film layer 2 in the lamination process, thereby ensuring the reliability of connection between the shielding layer 1 and the stratum of the circuit board; in addition, when the electromagnetic shielding film is pressed with the circuit board, the glue substance forming the glue film layer 2 is extruded into the concave part 13 to increase the glue containing amount, so that the board explosion phenomenon is not easy to occur, the problem that the existing electromagnetic shielding film explodes the board at high temperature due to insufficient glue containing amount is avoided, and the grounding of the electromagnetic shielding film is effectively ensured, so that the interference charge is led out.
In the embodiment of the present invention, in order to further secure the reliability of the grounding while improving the conduction efficiency, the pitch between each of the convex portions 12 and the adjacent concave portion 13 in the present embodiment is the same. By setting the interval between each of the convex portions 12 and the adjacent concave portion 13 to be the same, the conductor particles 3 on the convex portion 12 can uniformly pierce the adhesive film layer 2, thereby further ensuring the reliability of connection between the shielding layer 1 and the ground layer of the circuit board, while improving the conduction efficiency. Preferably, each of the projections 12 has the same shape; the shape of each concave part 13 is the same; wherein each convex part 12 has an axisymmetric structure; each concave part 13 has an axisymmetric structure; of course, each of the convex portions 12 may be a non-axisymmetric structure, and each of the concave portions 13 may be a non-axisymmetric structure. Because the distance between each convex part 12 and the adjacent concave part 13 is the same, and the shape of each convex part 12 is the same, the shape of each concave part 13 is the same, so that the glue containing amount on the surface of the shielding layer 1 is uniform, the explosion plate is further avoided, the grounding of the electromagnetic shielding film is further ensured, and the interference charge is led out.
In an embodiment of the present invention, the method for preparing the electromagnetic shielding film further includes: a protective film layer 4 is formed on a side of the shielding layer 1 away from the adhesive film layer 2.
In step S11, the forming the shielding layer 1 specifically includes:
s21, forming a protective film layer 4 on the carrier film;
s22, forming a shielding layer 1 on the protective film layer 4; wherein the shielding layer 1 may be formed on the protective film layer 4 by one or more processes of physical roughening, chemical plating, physical vapor deposition, chemical vapor deposition, evaporation plating, sputtering plating, electroplating, and mixed plating; or alternatively, the first and second heat exchangers may be,
s31, forming a shielding layer 1 on the surface of the strippable layer with the carrier; wherein the shielding layer 1 may be formed on the peelable layer surface of the tape carrier by one or more processes of physical roughening, electroless plating, physical vapor deposition, chemical vapor deposition, evaporation plating, sputter plating, electroplating, and mixed plating;
s32, forming a protective film layer 4 on the shielding layer 1;
s33, peeling the peelable layer with the carrier.
In the embodiment of the present invention, forming the shielding layer 1 on the protective film layer 4/the peelable layer with carrier specifically includes:
s41, forming a shielding layer 1 on the flat surface or the non-flat surface of the peelable layer of the protective film layer 4/the carrier;
s42, performing surface treatment on the shielding layer 1 through one or more processes of physical roughening, chemical plating, physical vapor deposition, chemical vapor deposition, evaporation plating, sputtering plating, electroplating and mixed plating; or alternatively, the first and second heat exchangers may be,
s51, the shielding layer 1 is formed on the non-planar surface of the protective film layer 4/carrier-carrying peelable layer.
In this embodiment of the present invention, after forming the shielding layer 1, the method further includes: convex conductor particles 3 are formed on the non-planar surface of the shielding layer 1. Specifically, the conductor particles 3 may be formed on the non-planar surface of the shielding layer 1 by one or more processes of physical roughening, electroless plating, physical vapor deposition, chemical vapor deposition, evaporation plating, sputter plating, electroplating, and hybrid plating.
In the embodiment of the present invention, the protective film layer 4 and the adhesive film layer 2 can closely contact through the through hole 11, so that the peel strength between the protective film layer 4 and the shielding layer 1 can be effectively improved, that is, the protective film layer 4 and the shielding layer 1 are not easy to peel.
In step S12, a film layer 2 is formed on the non-flat surface of the shielding layer 1, specifically:
s61, coating a glue film layer 2 on the release film;
s62, pressing and transferring the adhesive film layer 2 onto the non-flat surface of the shielding layer 1; or alternatively, the first and second heat exchangers may be,
and S71, coating a glue film layer 2 on the non-flat surface of the shielding layer 1.
In summary, the embodiment of the invention provides an electromagnetic shielding film, a circuit board and a preparation method of the electromagnetic shielding film, wherein the electromagnetic shielding film comprises a shielding layer 1 and a film layer 2, the film layer 2 is arranged on the shielding layer 1, one surface of the shielding layer 1 close to the film layer 2 is a non-flat surface, and through holes 11 penetrating through the upper surface and the lower surface of the shielding layer 1 are arranged on the shielding layer 1, so that volatile matters in the film layer 2 are exhausted through the through holes 11 of the shielding layer 1 at high temperature, the problem that the volatile matters in the film layer 2 are difficult to exhaust at high temperature is avoided, peeling between the electromagnetic shielding film and a stratum of the circuit board due to foaming and layering of the electromagnetic shielding film is avoided, and the grounding of the electromagnetic shielding film and the derivation of interference charges are further ensured; in addition, the non-flat surface of the shielding layer 1 pierces the adhesive film layer 2 and is connected with the stratum of the circuit board when the electromagnetic shielding film is pressed with the circuit board, so that the stratum connection of the shielding layer 1 and the circuit board is ensured, the grounding of the electromagnetic shielding film is further ensured, and interference charges are led out; in addition, because the one side of shielding layer 1 near glued membrane layer 2 is the non-flat surface, consequently when electromagnetic shielding film and circuit board are pressed, constitute glued class material of glued membrane layer 2 and be extruded in this non-flat surface's concave position to increase hold the volume of gluing, thereby be difficult to appear exploding the board phenomenon, avoided current electromagnetic shielding film because hold the volume of gluing not enough and lead to the problem of high temperature exploding the board, and then guaranteed electromagnetic shielding film ground connection effectively, thereby derive the interference charge.
The foregoing is merely a preferred embodiment of the present invention, and it should be noted that modifications and substitutions can be made by those skilled in the art without departing from the technical principles of the present invention, and these modifications and substitutions should also be considered as being within the scope of the present invention.

Claims (14)

1. The electromagnetic shielding film is characterized by comprising a shielding layer and a film layer, wherein the film layer is arranged on the shielding layer; one surface of the shielding layer, which is close to the adhesive film layer, is a non-flat surface, and a through hole penetrating through the upper surface and the lower surface of the shielding layer is formed in the shielding layer;
wherein the area of the through hole is 0.1 mu m 2 -1mm 2 。
2. The electromagnetic shielding film of claim 1, wherein a side of the shielding layer adjacent to the adhesive film layer comprises a plurality of protrusions and a plurality of recesses, the plurality of protrusions and the plurality of recesses being spaced apart.
3. The electromagnetic shielding film according to claim 1, wherein the shielding layer is provided with convex conductor particles on a side thereof adjacent to the adhesive film layer.
4. An electromagnetic shielding film according to claim 3, wherein the conductor particles have a height of 0.1 μm to 30 μm.
5. The electromagnetic shielding film according to any one of claims 1 to 4, wherein the thickness of the shielding layer is 0.1 μm to 45 μm and the thickness of the adhesive film layer is 1 μm to 80 μm.
6. The electromagnetic shielding film according to any one of claims 1 to 4, wherein the adhesive film layer includes an adhesive layer containing conductive particles; or, the adhesive film layer comprises an adhesive layer without conductive particles.
7. The electromagnetic shielding film of any one of claims 1-4, further comprising a protective film layer disposed on a side of the shielding layer remote from the adhesive film layer.
8. The electromagnetic shielding film according to any one of claims 1-4, wherein the number of the through holes in the shielding layer is 10-1000 per square centimeter.
9. A circuit board, characterized by comprising a circuit board body and the electromagnetic shielding film according to any one of claims 1-8, wherein the electromagnetic shielding film is pressed with the circuit board body through the adhesive film layer, and the shielding layer pierces the adhesive film layer and is electrically connected with a stratum of the circuit board body.
10. The preparation method of the electromagnetic shielding film is characterized by comprising the following steps of:
forming a shielding layer; one surface of the shielding layer is a non-flat surface, and a through hole penetrating through the upper surface and the lower surface of the shielding layer is formed in the shielding layer; wherein the area of the through hole is 0.1 mu m 2 -1mm 2 ；
And forming a glue film layer on the non-flat surface of the shielding layer.
11. The method of manufacturing an electromagnetic shielding film according to claim 10, further comprising:
and forming a protective film layer on one surface of the shielding layer, which is far away from the adhesive film layer.
12. The method for preparing an electromagnetic shielding film according to claim 10, wherein the forming the shielding layer specifically includes:
forming a protective film layer on the carrier film;
forming a shielding layer on the protective film layer; or alternatively, the first and second heat exchangers may be,
forming a shielding layer on the surface of the strippable layer with the carrier;
forming a protective film layer on the shielding layer;
the peelable layer of the tape carrier is peeled off.
13. The method for preparing an electromagnetic shielding film according to claim 10, wherein the forming of the shielding layer further comprises:
convex conductor particles are formed on the non-planar surface of the shielding layer.
14. The method for producing an electromagnetic shielding film according to any one of claims 10 to 13, wherein,
forming a glue film layer on the non-flat surface of the shielding layer, wherein the glue film layer comprises the following specific steps:
coating a glue film layer on the release film;
pressing and transferring the adhesive film layer onto the non-flat surface of the shielding layer; or, coating a glue film layer on the non-flat surface of the shielding layer.
CN201810743106.9A 2018-07-06 2018-07-06 Electromagnetic shielding film, circuit board and preparation method of electromagnetic shielding film Active CN110691498B (en)

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CN203722915U (en) * 2014-01-14 2014-07-16 广州方邦电子有限公司 Electromagnetic wave shielding film used for printed circuit board and printed circuit board containing shielding film
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CN103763893A (en) * 2014-01-14 2014-04-30 广州方邦电子有限公司 Electromagnetic wave shielding film and method for manufacturing circuit board with same
CN203722915U (en) * 2014-01-14 2014-07-16 广州方邦电子有限公司 Electromagnetic wave shielding film used for printed circuit board and printed circuit board containing shielding film
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