CN110769586A - 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 PDFInfo
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- CN110769586A CN110769586A CN201810847390.4A CN201810847390A CN110769586A CN 110769586 A CN110769586 A CN 110769586A CN 201810847390 A CN201810847390 A CN 201810847390A CN 110769586 A CN110769586 A CN 110769586A
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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
- 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
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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
- H05K9/0007—Casings
- H05K9/002—Casings with localised screening
- H05K9/0022—Casings with localised screening of components mounted on printed circuit boards [PCB]
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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
Abstract
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 resin film layer, a first shielding layer and a glue film layer, a first through hole is formed in the resin film layer, a resin bulge is arranged at the first through hole, and the resin bulge is formed by solidifying resin after the resin flows from one side of the first through hole to the other side; the first shielding layer is arranged on one side, close to the resin bulge, of the resin film layer and covers the resin bulge, so that a bulge part is formed on the outer surface of the first shielding layer at a position corresponding to the resin bulge; the glue film layer is arranged on one side, away from the resin film layer, of the first shielding layer, and the protruding portion extends into the glue film layer, so that the protruding portion can guarantee that the first shielding layer can smoothly pierce through the glue film layer in the pressing process and is in contact with the ground of the circuit board, and then normal derivation of interference charges is guaranteed, and a shielding function is achieved.
Description
Technical Field
The invention relates to the 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 are further miniaturized, light-weighted and highly-densely assembled, and the development of flexible circuit boards is greatly promoted, so that the integration of component devices and wire connection is realized. The flexible circuit board can be widely applied to industries such as mobile phones, liquid crystal display, communication, aerospace and the like.
Under the push of the international market, the functional flexible printed circuit board is dominant in the flexible printed circuit board market, and an important index for evaluating the performance of the functional flexible printed circuit board is Electromagnetic Shielding (EMI Shielding for short), along with the integration of the functions of communication equipment such as mobile phones, the internal components thereof are sharply high-frequency and high-speed, for example: the mobile phone functions become necessary functions in addition to the original audio transmission function, furthermore, WLAN (Wireless Local Area network), GPS (Global Positioning System) and internet function are popular, and the integration of sensing components in the future makes the trend of rapid high-frequency and high-speed components more inevitable.
At present, a shielding film commonly used for an existing circuit board comprises a shielding layer and a conductive adhesive layer, wherein the shielding layer is connected with a circuit board stratum through the conductive adhesive layer, and then interference charges are guided into the circuit board stratum to realize shielding. However, at high temperature, due to the expansion of the conductive adhesive layer, the conductive particles originally in contact with each other in the conductive adhesive layer are pulled apart or the conductive particles originally in contact with the circuit board stratum are pulled apart, which results in grounding failure, and the interference charges cannot be rapidly led out, so that the shielding function cannot be realized.
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 realize the reliable connection of the shielding film and the circuit board stratum and further realize the shielding function with high reliability.
In order to achieve the above object, an embodiment of the present invention provides an electromagnetic shielding film, including a resin film layer, a first shielding layer, and an adhesive film layer, where the resin film layer is provided with a first through hole penetrating through upper and lower surfaces of the resin film layer, the first through hole is provided with a resin protrusion, and the resin protrusion is formed by resin flowing from one side of the first through hole to the other side of the first through hole and then solidifying; the first shielding layer is arranged on one side, close to the resin bulge, of the resin film layer and covers the resin bulge, so that a bulge part is formed on the outer surface of the first shielding layer at a position corresponding to the resin bulge; the glue film layer is arranged on one side, away from the resin film layer, of the first shielding layer, and the protruding portion extends into the glue film layer.
As a modification of the above, the resin projection is formed by solidification of resin at a curing temperature after the resin flows from one side to the other side of the first through hole at normal temperature; or the like, or, alternatively,
the resin protrusion is formed by instantly cooling after resin flows from one side to the other side of the first through hole at a melting temperature.
As an improvement of the above scheme, the surface of the convex part is provided with convex conductor particles; the height of the conductor particles is 0.1-30 μm.
As an improvement of the above scheme, the adhesive film layer includes an adhesive layer containing conductive particles; or the adhesive film layer comprises an adhesion layer without conductive particles.
As an improvement of the above scheme, the first shielding layer respectively comprises one or more of a metal shielding layer, a carbon nanotube shielding layer, a ferrite shielding layer and a graphene shielding layer.
As a modification of the above, the metal shielding layer includes a single metal shielding layer and/or an alloy shielding layer; the single metal shielding layer is made of any one of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver and gold, and the alloy shielding layer is made of any two or more of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver and gold.
As an improvement of the above scheme, the electromagnetic shielding film further comprises a protective film layer, and the protective film layer is arranged on one side of the resin film layer, which is far away from the first shielding layer.
Compared with the prior art, the embodiment of the invention discloses an electromagnetic shielding film, by arranging the first through hole on the resin film layer, and the resin projection formed by solidification of resin after flowing from one side to the other side of the first through hole is provided at the first through hole, meanwhile, the first shielding layer is arranged on one side of the resin film layer close to the resin bulge and covers the resin bulge, thereby forming a convex portion at a position of the outer surface of the first shield layer corresponding to the resin protrusion, the adhesive film layer is arranged on one side of the first shielding layer far away from the resin film layer, so that the first shielding layer can be ensured to smoothly pierce the adhesive film layer by the bulge part in the pressing process, the grounding is reliable, interference charges are guaranteed to be led out normally, and the shielding function is achieved.
The embodiment of the invention also correspondingly provides a circuit board, which comprises a printed circuit board and the electromagnetic shielding film, wherein the electromagnetic shielding film is laminated with the printed circuit board through the adhesive film layer; the protruding part pierces the adhesive film layer and extends to the ground layer of the printed circuit board.
Compared with the prior art, the embodiment of the invention discloses a circuit board which comprises a printed circuit board and any one of the electromagnetic shielding films, wherein the electromagnetic shielding film is pressed with the printed circuit board through a film adhesive layer, and the bulge part pierces the film adhesive layer and is connected with a ground layer of the printed circuit board, so that interference charges are smoothly led out, and the shielding function is further realized.
The embodiment of the invention also correspondingly provides a preparation method of the electromagnetic shielding film, which is suitable for preparing any one of the electromagnetic shielding films, and comprises the following steps:
s1, forming a resin film layer; wherein the resin film layer has a first through hole penetrating through upper and lower surfaces thereof;
s2, forming a resin bulge at the first through hole; wherein the resin projection protrudes out of the first through hole;
s3, forming a first shielding layer on the side of the resin film layer where the resin bump is formed, and forming a bump on the outer surface of the first shielding layer at a position corresponding to the resin bump by covering the resin bump with the first shielding layer;
and S4, forming a film adhesive layer on one side of the first shielding layer far away from the resin film layer.
As a modification of the above, in step S2, the forming a resin protrusion at the first through hole includes:
and arranging resin at the first through hole, and solidifying the resin after the resin flows from one side to the other side of the first through hole, so that a resin bulge is formed at the first through hole.
As an improvement of the above scheme, before forming the glue film layer on the side of the first shielding layer away from the resin film layer, the method further comprises the following steps:
forming conductor particles on the outer surface of the protrusion part by one or more processes of physical roughening, chemical plating, physical vapor deposition, chemical vapor deposition, evaporation plating, sputtering plating, electroplating and hybrid plating.
As a modification of the above scheme, in step S4, the forming a glue film layer on the side of the first shielding layer away from the resin film layer specifically includes:
coating an adhesive film layer on a release film, and then transferring the adhesive film layer to one side of a first shielding layer far away from a resin film layer in a pressing manner, so that the adhesive film layer is formed on one side of the first shielding layer far away from the resin film layer; or
And directly coating an adhesive film layer on one side of the first shielding layer where the bulge is formed, so that the adhesive film layer is formed on one side of the first shielding layer far away from the resin film layer.
Compared with the prior art, according to the preparation method of the electromagnetic shielding film provided by the embodiment of the invention, the first shielding layer is formed on one side of the resin film layer on which the resin protrusion is formed, and the first shielding layer covers the resin protrusion, so that the protrusion part is formed on the outer surface of the first shielding layer at the position corresponding to the resin protrusion, and the adhesive film layer is formed on one side of the first shielding layer, so that the formed protrusion part can ensure that the first shielding layer smoothly pierces through the adhesive film layer in the pressing process, reliable grounding is realized, and the practicability is strong.
Drawings
Fig. 1 is a schematic view of an angle structure of an electromagnetic shielding film in embodiment 1 of the present invention;
fig. 2 is a schematic view of another angle structure of the electromagnetic shielding film in embodiment 1 of the present invention;
fig. 3 is a schematic structural view of an electromagnetic shielding film in embodiment 2 of the present invention;
fig. 4 is a schematic structural view of a wiring board in embodiment 3 of the present invention;
fig. 5 is a schematic flow chart of a method for manufacturing an electromagnetic shielding film in embodiment 4 of the present invention.
Wherein, 1, resin film layer; 11. a first through hole; 12. resin bumps; 2. a first shielding layer; 21. a boss portion; 22. a conductive particle; 3. a glue film layer; 4. a protective film layer; 5. a printed wiring board.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Fig. 1 is a schematic view of an angle structure of the electromagnetic shielding film according to embodiment 1 of the present invention;
fig. 2 is a schematic structural view of another angle of the electromagnetic shielding film provided in embodiment 1 of the present invention;
referring to fig. 1 and 2, the electromagnetic shielding film includes a resin film layer 1, a first shielding layer 2 and a glue film layer 3, wherein a first through hole 11 penetrating through the upper and lower surfaces of the resin film layer 1 is formed in the resin film layer 1, a resin protrusion 12 is formed at the first through hole 11, and the resin protrusion 12 is formed by resin flowing from one side of the first through hole 11 to the other side and then solidifying; the first shielding layer 2 is arranged on one side of the resin film layer close to the resin bulge 12 and covers the resin bulge 12, so that a bulge part 21 is formed on the outer surface of the first shielding layer 2 at a position corresponding to the resin bulge 12; the adhesive film layer is arranged on one side, away from the resin film layer, of the first shielding layer, and the protruding portion 21 extends into the adhesive film layer 3.
In the embodiment of the present invention, the first through hole 11 is formed on the resin film layer 1, the resin protrusion 12 formed by solidifying the resin flowing from one side of the first through hole 11 to the other side is formed at the first through hole 11, and the first shielding layer 2 is arranged on one side of the resin film layer 1 close to the resin protrusion 12 and covers the resin protrusion 12, so that the protrusion 21 is formed at the position of the outer surface of the first shielding layer 2 corresponding to the resin protrusion 12, and the glue film layer 3 is arranged on one side of the first shielding layer 2 far from the resin film layer 1, so that the protrusion 21 ensures that the first shielding layer 2 can smoothly penetrate through the glue film layer 3 during the pressing process, so as to achieve reliable grounding, and further ensure that the interference charges are normally led out under the matching of the resin film layer 1 and the first shielding layer 2, the shielding function is realized. The electromagnetic shielding film of this embodiment need not to set up the conductive adhesive layer, has consequently avoided effectively when high temperature, because the conductive adhesive layer inflation leads to the problem of ground connection inefficacy.
In the embodiment of the present invention, the process of forming the resin projection 12 is specifically represented as follows: in one preferred embodiment, the resin protrusion 12 is formed by instant cooling after the resin flows from one side to the other side of the first through hole 11 at the melting temperature. In another preferred embodiment, the resin is a cured adhesive, and the forming process of the resin protrusion 12 is embodied as follows: at normal temperature, after the liquefied resin flows from one side to the other side of the first through-hole 11, it is solidified at a curing temperature, thereby forming the resin protrusion 12.
In the embodiment of the present invention, it should be noted that the structure of the resin protrusion 12 shown in the drawings is merely exemplary. Since the resin projection 12 is formed by solidification after the resin flows from one side to the other side of the first through hole 11, in either case, the resin flows out almost completely from the first through hole 11 without remaining in the first through hole 11, and thus the resin projection 12 can be formed as shown in the drawing, the resin projection 12 being formed at the boundary of the first through hole 11 and the first shield layer 2; in another case, resin remains in the first through hole 11, and the first through hole 11 is even filled with resin, so that one end of the resin projection 12 formed is located in the first through hole 11 and the other end of the resin projection 12 protrudes out of the first through hole 11; in still another case, resin remains on the surface of the resin film layer 1 on the side away from the first shielding layer 2, and therefore, the resin protrusion 12 may be formed to penetrate through the first through hole 11. The resin protrusion 12 of the present invention is not limited to the shape shown in the drawings, and any resin protrusion having a piercing ability is within the scope of the present invention.
In the embodiment of the present invention, the shape of the protrusion 21 may be the same as the shape of the resin protrusion 12, or may be different from the shape of the resin protrusion 12, and the shape of the protrusion 21 shown in the drawings is merely exemplary.
In the embodiment of the present invention, in order to further ensure that the resin projection 12 can be formed at the first through hole 11, it is preferable that the cross-sectional area of the first through hole 11 in the embodiment is 0.1 μm2-1mm2。
In addition, in this example, each 1cm2The number of the first through holes 11 in the resin film layer 1 is 10-1000. Correspondingly, every 1cm2The number of the resin protrusions 12 in the resin film layer 1 is 10-1000; it should be noted that, since the first shielding layer 2 covers the resin protrusion 12, so that the protrusion 21 is formed at the position of the outer surface of the first shielding layer 2 corresponding to the resin protrusion 12, the number of the protrusions 21 corresponds to the number of the resin protrusions 12, thereby ensuring that the first shielding layer 2 can smoothly pierce the adhesive film layer 3.
In the embodiment of the present invention, the first through holes 11 may be regularly or irregularly distributed on the resin film layer 1; wherein, the first through holes 11 are regularly distributed on the resin film layer 1, which means that the shapes of the first through holes 11 are the same and are uniformly distributed on the resin film layer 1; the first through holes 11 are irregularly distributed on the resin film layer 1, which means that the shapes of the first through holes 11 are different and the first through holes are irregularly distributed on the resin film layer 1. Preferably, the shape of each first through hole 11 is the same, and each first through hole 11 is uniformly distributed on the resin film layer 1. In addition, the first through hole 11 may be a circular through hole, and may also be a through hole of any other shape, and the drawings of the present invention only illustrate that the first through hole 11 is a circular through hole, but the first through hole 11 of any other shape is within the scope of the present invention.
In the embodiment of the present invention, the resin film layer 1 includes a first surface and a second surface which are oppositely arranged, and the first surface is in contact with the first shielding layer 2; the second surface is in contact with the protective film layer 4. The first surface and the second surface may be surfaces of any shape, for example, flat surfaces as shown in fig. 1, uneven surfaces with undulations, or other rough surfaces; in addition, the first surface and the second surface may be regular surfaces or irregular surfaces. The drawings of the present invention are only for illustrating that the first surface and the second surface are flat surfaces, and any other shapes of the first surface and the second surface are within the protection scope of the present invention. In addition, the resin film layer 1 shown in the drawings of the present embodiment may have a single-layer structure or a multi-layer structure.
In the embodiment of the present invention, the thickness of the first shielding layer 2 is 0.1 μm to 45 μm. In order to ensure that the first shielding layer 2 has good conductivity, the first shielding layer 2 comprises one or more of a metal shielding layer, a carbon nanotube shielding layer, a ferrite shielding layer and a graphene shielding layer; the single metal shielding layer is made of any one of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver and gold, and the alloy shielding layer is made of any two or more of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver and gold.
In the embodiment of the present invention, it should be noted that the first shielding layer 2 in the drawings of the present embodiment may have a single-layer structure or a multi-layer structure. In addition, the first shielding layer 2 of the present embodiment can be provided in a grid shape, a foam shape, etc. according to the requirements of actual production and application.
In the embodiment of the present invention, one of the structures of the adhesive film layer 3 is specifically represented as follows: the glue film layer 3 comprises an adhesion layer containing conductive particles. By making the adhesive film layer 3 include an adhesive layer containing conductive particles, the adhesive film layer 3 not only has an adhesive function to tightly adhere the wiring board and the electromagnetic shielding film, but also has a conductive function, which is matched with the first shielding layer 2 to rapidly introduce interfering electrons into the ground layer of the wiring board. The conductive particles can be mutually separated conductive particles or aggregated large-particle conductive particles; when the conductive particles are mutually separated, the area of electrical contact can be further increased, and the uniformity of the electrical contact is improved; and when the conductive particles are large agglomerated conductive particles, the piercing strength can be increased.
In the embodiment of the present invention, another structure of the adhesive film layer 3 is specifically represented as follows: the adhesive film layer 3 includes an adhesive layer containing no conductive particles. The adhesive film layer 3 has an adhesive effect by making the adhesive film layer 3 include an adhesive layer containing no conductive particles, so that the wiring board and the electromagnetic shielding film are tightly adhered, and meanwhile, since the adhesive film layer 3 contains no conductive particles, the insertion loss of the wiring board in the use process is reduced, the shielding effect is improved, and the bending property of the wiring board is improved.
In the embodiment of the present invention, the thickness of the adhesive film layer 3 is 1 μm to 80 μm. The glue film layer 3 is made of the following materials: modified epoxy resins, acrylic resins, modified rubbers, and modified thermoplastic polyimides. In addition, the outer surface of the adhesive film layer 3 may be a flat surface without undulation, or may be a non-flat surface with gentle undulation.
As shown in fig. 1, in order to protect the resin film layer 1, the electromagnetic shielding film of the present embodiment further includes a protection film layer 4, and the protection film layer 4 is disposed on a side of the resin film layer 1 away from the first shielding layer 2. The protective film layer 4 plays a role in protection, so that the resin film layer 1 is not scratched or damaged in the using process, and the high shielding effectiveness of the resin film 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 after epoxy resin ink is cured, a film layer formed after polyurethane ink is cured, a film layer formed after modified acrylic resin is cured or a film layer formed after polyimide resin is cured.
In the embodiment of the present invention, it should be noted that the electromagnetic shielding film may have a repeating multilayer structure. Specifically, the electromagnetic shielding film may include a plurality of resin film layers 1 stacked in sequence, and the first shielding layer 2 and the adhesive film layer 3 are sequentially disposed on one side of an integral formed by the plurality of resin film layers 1, and the protective film layer 4 is disposed on the other side; with first shielding layer 2 contacts first through-hole 11 department on the resin rete 1 is equipped with resin arch 12, first shielding layer 2 covers resin arch 12, thereby the surface of first shielding layer 2 with the position that resin arch 12 corresponds forms bellying 21, just bellying 21 stretches into glue film layer 2.
Fig. 3 is a schematic structural view of the electromagnetic shielding film according to embodiment 2 of the present invention;
as shown in fig. 3, the electromagnetic shielding film in the present embodiment is different from embodiment 1 in that the surface of the protruding portion 21 is provided with convex conductor particles 22. By arranging the conductor particles 22 on the surface of the protruding portion 21, it is further ensured that the protruding portion 21 can ensure that the first shielding layer 2 smoothly pierces the adhesive film layer 3 in the pressing process, and further ensure that the interference charges are normally led out.
Preferably, the conductive particles 22 are distributed in a concentrated manner on the outwardly protruding positions of the surface of the protruding portion 21, so that the adhesive film layer 3 is easier to pierce. Of course, the non-convex portions of the surface of the convex portion 21 may have the conductive particles 22 distributed. In addition, the conductive particles 22 may also be distributed on other positions of the first shielding layer 2 near the surface of the adhesive film layer 3, not only on the surface of the protruding portion 21, as shown in fig. 3. Of course, the conductor particles 22 may also be distributed only on the projections 21.
In a specific implementation, as shown in fig. 3, the first shielding layer 2 may be formed first, and then the conductor particles 22 may be formed on the side of the first shielding layer 2 away from the resin film layer 1 by other processes. Of course, the first shielding layer 2 and the conductive particles 22 may be an integral structure formed by a one-step molding process. It should be noted that the conductor particles 22 are intensively distributed on the protruding portion 21.
In the embodiment of the present invention, the conductor particles 22 may be spaced from the outer surface of the adhesive film layer 3, and may also contact with the outer surface of the adhesive film layer 3 or extend out of the outer surface of the adhesive film layer 3.
In the embodiment of the present invention, in order to ensure that the protruding portion 21 can smoothly penetrate through the adhesive film layer 3, the height of the conductor particles 22 is preferably 0.1 μm to 30 μm.
In an embodiment of the present invention, the conductor particles 22 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; the single metal particles are made of any one of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver and gold, and the alloy particles are made of any two or more of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver and gold. The conductive particles 22 may be the same as or different from the material of the first shielding layer 2.
In the embodiment of the present invention, it should be noted that the shape of the conductor particles 22 shown in fig. 3 is only an example, and the conductor particles 22 may also be in other shapes such as clusters, ice-hanging shapes, stalactites, and dendrites due to differences in process means and parameters. The conductive particles 22 in the present invention are not limited to the shapes shown in the drawings and described above, and any conductive particles having piercing and conductive functions are within the scope of the present invention.
In the embodiment of the present invention, it should be noted that the electromagnetic shielding film may be a repeating multilayer structure; specifically, the electromagnetic shielding film may include a plurality of resin film layers 1 stacked in sequence, and the first shielding layer 2 and the adhesive film layer 3 are sequentially disposed on one side of an integral formed by the plurality of resin film layers 1, and the protective film layer 4 is disposed on the other side; with first shielding layer 2 contacts first through-hole 11 department on the resin film layer 1 is equipped with resin arch 12, first shielding layer 2 covers resin arch 12, thereby first shielding layer 2's surface with the position that resin arch 12 corresponds forms bellying 21, bellying 21 stretches into glue film layer 3, just the surface of bellying 21 sets up conductor granule 22. In addition, other structures and working principles of the electromagnetic shielding film of this embodiment are the same as those of embodiment 1, and are not further described herein.
Fig. 4 is a schematic structural diagram of a circuit board provided in embodiment 3 of the present invention;
as shown in fig. 4, an embodiment of the present invention further provides a circuit board, including a printed circuit board 5 and the electromagnetic shielding film described in embodiment 1, wherein the electromagnetic shielding film is pressed with the printed circuit board 5 through an adhesive film layer 3 of the electromagnetic shielding film; the boss 21 pierces the adhesive film layer 3 and extends to the ground layer of the printed wiring board 5.
In this embodiment, reference may be made to the description of embodiment 1 above for implementation of the electromagnetic shielding film, and details are not repeated here.
Preferably, the printed circuit board 5 is one of a flexible single-sided board, a flexible double-sided board, a flexible multilayer board, and a rigid-flex board.
In the embodiment of the present invention, with the above structure, in the pressing process, the protruding portion 21 on the first shielding layer 2 pierces through the glue film layer 3, so that at least a portion of the outer surface of the first shielding layer 2 is connected to the ground layer of the printed circuit board 5, and thus the interference charges are smoothly led out. In addition, it should be noted that, in the circuit board of this embodiment, the electromagnetic shielding film of embodiment 1 adopted in the structure of the circuit board may be replaced by the electromagnetic shielding film of embodiment 2, which is not described in detail herein.
Referring to fig. 5, a schematic flow chart of a method for preparing an electromagnetic shielding film according to embodiment 4 of the present invention is shown;
as shown in fig. 5, the method is suitable for preparing the electromagnetic shielding film according to embodiment 1, and includes the steps of:
s1, forming a resin film layer; wherein the resin film layer has a first through hole penetrating through upper and lower surfaces thereof;
specifically, the resin film layer is formed by: forming a protective film layer on a carrier film, and forming a resin film layer on the protective film layer; or
Forming a resin film layer on the surface of the strippable layer with the carrier, forming a protective film layer on the resin film layer, and stripping the strippable layer with the carrier;
wherein the resin film layer has a first through hole penetrating upper and lower surfaces thereof. The cross-sectional area of the first through-hole is 0.1 μm2-1mm2(ii) a Every 1cm2The number of the first through holes in the resin film layer is 10-1000.
S2, forming a resin bulge at the first through hole; wherein the resin projection protrudes out of the first through hole;
wherein, form the resin arch in first through-hole department, specifically be: and arranging resin at the first through hole, and solidifying the resin after the resin flows from one side to the other side of the first through hole, so that a resin bulge is formed at the first through hole. Specifically, in one of preferred modes, after a resin is provided at the first through hole and is caused to flow from one side to the other side of the first through hole at normal temperature, the resin is solidified at a curing temperature, thereby forming a resin protrusion at the first through hole. In yet another preferred embodiment, a resin is provided at the first through hole and instantaneously cooled after flowing from one side to the other side of the first through hole at a melting temperature, thereby forming a resin protrusion at the first through hole.
S3, forming a first shielding layer on the side of the resin film layer where the resin bump is formed, and forming a bump on the outer surface of the first shielding layer at a position corresponding to the resin bump by covering the resin bump with the first shielding layer;
and S4, forming a film adhesive layer on one side of the first shielding layer far away from the resin film layer.
Specifically, a glue film layer is coated on a release film, and then the glue film layer is transferred to one side, away from the resin film layer, of a first shielding layer in a pressing mode, so that the glue film layer is formed on one side, away from the resin film layer, of the first shielding layer; or
And directly coating an adhesive film layer on one side of the first shielding layer where the bulge is formed, so that the adhesive film layer is formed on one side of the first shielding layer far away from the resin film layer.
In another preferred embodiment suitable for preparing the electro-magnetic shielding film of embodiment 2, before step S4, the method further comprises the steps of:
forming conductor particles on the outer surface of the protrusion part by one or more processes of physical roughening, chemical plating, physical vapor deposition, chemical vapor deposition, evaporation plating, sputtering plating, electroplating and hybrid plating.
In the embodiment of the invention, the first shielding layer is formed on one side of the resin film layer where the resin protrusion is formed, and the first shielding layer covers the resin protrusion, so that the protrusion is formed on the outer surface of the first shielding layer at a position corresponding to the resin protrusion, and the adhesive film layer is formed on one side of the first shielding layer away from the resin film layer, so that the formed protrusion can ensure that the first shielding layer smoothly pierces through the adhesive film layer in the pressing process, reliable grounding is realized, and the practicability is strong.
To sum up, 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 resin film layer 1, a first shielding layer 2 and a glue film layer 3, wherein the resin film layer 1 is provided with a first through hole 11 penetrating through the upper surface and the lower surface of the resin film layer, a resin bulge 12 is arranged at the first through hole 11, and the resin bulge 12 is formed by solidifying resin after the resin flows from one side of the first through hole 11 to the other side; the first shielding layer 2 is arranged on one side of the first shielding film 1 close to the resin protrusion 12 and covers the resin protrusion 12, so that a protrusion part 21 is formed on the outer surface of the first shielding layer 2 corresponding to the resin protrusion 12; the glue film layer is arranged on one side, away from the resin film layer, of the first shielding layer, and the protruding portion 21 extends into the glue film layer 3. The first through hole 11 is formed in the resin film layer 1, the resin protrusion 12 formed by resin which is solidified after flowing from one side of the first through hole 11 to the other side is arranged at the first through hole 11, the first shielding layer 2 is arranged on one side of the first shielding film 1 close to the resin protrusion 12 and covers the resin protrusion 12, so that a protruding portion 21 is formed on the outer surface of the first shielding layer 2 at a position corresponding to the resin protrusion 12, and the adhesive film layer 3 is arranged on one side of the first shielding layer 2 far away from the resin film layer 1, so that the protruding portion 21 ensures that the first shielding layer 2 can smoothly pierce the adhesive film layer 3 in the pressing process, reliable grounding is achieved, normal leading-out of interference charges is guaranteed, and a shielding function is achieved.
The foregoing is directed to the preferred embodiment of the present invention, and it is understood that various changes and modifications may be made by one skilled in the art without departing from the spirit of the invention, and it is intended that such changes and modifications be considered as within the scope of the invention.
Claims (12)
1. An electromagnetic shielding film is characterized by comprising a resin film layer, a first shielding layer and a glue film layer, wherein a first through hole penetrating through the upper surface and the lower surface of the resin film layer is formed in the resin film layer, a resin bulge is arranged at the first through hole, and the resin bulge is formed by solidifying resin after the resin flows from one side of the first through hole to the other side; the first shielding layer is arranged on one side, close to the resin bulge, of the resin film layer and covers the resin bulge, so that a bulge part is formed on the outer surface of the first shielding layer at a position corresponding to the resin bulge; the glue film layer is arranged on one side, away from the resin film layer, of the first shielding layer, and the protruding portion extends into the glue film layer.
2. The electro-magnetic shielding film according to claim 1, wherein the resin protrusion is formed by solidifying at a curing temperature after a resin flows from one side to the other side of the first through hole at a normal temperature; or the like, or, alternatively,
the resin protrusion is formed by instantly cooling after resin flows from one side to the other side of the first through hole at a melting temperature.
3. The electromagnetic shielding film according to claim 1, wherein the surface of the convex portion is provided with convex conductor particles; the height of the conductor particles is 0.1-30 μm.
4. The electromagnetic shielding film of claim 1, wherein the adhesive layer comprises an adhesive layer containing conductive particles; or the like, or, alternatively,
the adhesive film layer comprises an adhesion layer without conductive particles.
5. The electromagnetic shielding film of any of claims 1-4, wherein the first shielding layer comprises one or more of a metal shielding layer, a carbon nanotube shielding layer, a ferrite shielding layer, and a graphene shielding layer.
6. The electromagnetic shielding film according to claim 5, wherein the metallic shielding layer comprises a single metallic shielding layer and/or an alloy shielding layer; the single metal shielding layer is made of any one of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver and gold, and the alloy shielding layer is made of any two or more of aluminum, titanium, zinc, iron, nickel, chromium, cobalt, copper, silver and gold.
7. The electro-magnetic shielding film of any one of claims 1-4, further comprising a protective film layer disposed on a side of the resin film layer remote from the first shielding layer.
8. A circuit board comprising a printed wiring board and the electromagnetic shielding film of any one of claims 1 to 7, wherein the electromagnetic shielding film is laminated with the printed wiring board through an adhesive film layer thereof; the protruding part pierces the adhesive film layer and extends to the ground layer of the printed circuit board.
9. A method for preparing an electro-magnetic shielding film, which is suitable for preparing the electro-magnetic shielding film of any one of claims 1 to 7, comprising the steps of:
s1, forming a resin film layer; wherein the resin film layer has a first through hole penetrating through upper and lower surfaces thereof;
s2, forming a resin bulge at the first through hole; wherein the resin projection protrudes out of the first through hole;
s3, forming a first shielding layer on the side of the resin film layer where the resin bump is formed, and forming a bump on the outer surface of the first shielding layer at a position corresponding to the resin bump by covering the resin bump with the first shielding layer;
and S4, forming a film adhesive layer on one side of the first shielding layer far away from the resin film layer.
10. The method for preparing an electro-magnetic shielding film according to claim 9, wherein in step S2, the forming of the resin protrusion at the first through hole includes:
and arranging resin at the first through hole, and solidifying the resin after the resin flows from one side to the other side of the first through hole, so that a resin bulge is formed at the first through hole.
11. The method for preparing an electro-magnetic shielding film according to claim 9, further comprising the steps of, before forming an adhesive film layer on a side of the first shielding layer away from the resin film layer:
forming conductor particles on the outer surface of the protrusion part by one or more processes of physical roughening, chemical plating, physical vapor deposition, chemical vapor deposition, evaporation plating, sputtering plating, electroplating and hybrid plating.
12. The method for preparing an electromagnetic shielding film according to claim 9, wherein in step S4, the step of forming an adhesive film layer on the side of the first shielding layer away from the resin film layer includes:
coating an adhesive film layer on a release film, and then transferring the adhesive film layer to one side of the first shielding layer far away from the resin film layer in a pressing manner, so that the adhesive film layer is formed on one side of the first shielding layer far away from the resin film layer; or
And directly coating an adhesive film layer on one side of the first shielding layer, which is far away from the resin film layer, so that the adhesive film layer is formed on one side of the first shielding layer, which is far away from the resin film layer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201810847390.4A CN110769586A (en) | 2018-07-27 | 2018-07-27 | Electromagnetic shielding film, circuit board and preparation method of electromagnetic shielding film |
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| CN201810847390.4A CN110769586A (en) | 2018-07-27 | 2018-07-27 | Electromagnetic shielding film, circuit board and preparation method of electromagnetic shielding film |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116782620A (en) * | 2023-07-03 | 2023-09-19 | 广州方邦电子股份有限公司 | Electromagnetic shield cover and circuit board |
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- 2018-07-27 CN CN201810847390.4A patent/CN110769586A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116782620A (en) * | 2023-07-03 | 2023-09-19 | 广州方邦电子股份有限公司 | Electromagnetic shield cover and circuit board |
| CN116782620B (en) * | 2023-07-03 | 2024-03-08 | 广州方邦电子股份有限公司 | Electromagnetic shield cover and circuit board |
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