CN211702875U

CN211702875U - Electromagnetic shielding film and circuit board

Info

Publication number: CN211702875U
Application number: CN201922493901.XU
Authority: CN
Inventors: 苏陟; 高强
Original assignee: Guangzhou Fangbang Electronics Co Ltd
Current assignee: Guangzhou Fangbang Electronics Co Ltd
Priority date: 2019-12-30
Filing date: 2019-12-30
Publication date: 2020-10-16
Anticipated expiration: 2029-12-30

Abstract

The utility model relates to a shielding film technical field discloses an electromagnetic shielding film and circuit board, and electromagnetic shielding film includes shielding layer, first electromagnetic wave absorbed layer, first insulating layer and rete, and the shielding layer is located to first electromagnetic wave absorbed layer between shielding layer and the first insulating layer, and the rete is located the one side that first electromagnetic wave absorbed layer was kept away from to first insulating layer. The first electromagnetic wave absorption layer is arranged, so that the electromagnetic shielding film has the function of absorbing electromagnetic waves, and when the electromagnetic shielding film is applied to the circuit board, the electromagnetic shielding film can effectively absorb the electromagnetic waves generated by the circuit board, so that the electromagnetic interference is effectively shielded, and the normal work of the circuit board is ensured; meanwhile, the first heat insulation layer is arranged to absorb or insulate heat generated when the first electromagnetic wave absorption layer absorbs electromagnetic waves and heat generated by external devices, so that the electromagnetic shielding film is ensured to have good electromagnetic shielding efficiency.

Description

Electromagnetic shielding film and circuit board

Technical Field

The utility model relates to a shielding film technical field especially relates to an electromagnetic shielding film and circuit board.

Background

With the development of miniaturization, light weight, multiple functions and high assembly density of modern electronic equipment, the structure of the circuit board tends to be fine and highly integrated, and is required to bear high-speed signal transmission. Therefore, the circuit density on the circuit board is increased, the circuit spacing is closer, and the operating frequency is higher and wider, which leads to more and more serious electromagnetic interference between circuits.

At present, in order to realize electromagnetic shielding, an electromagnetic shielding film is generally provided on a circuit board. However, the existing electromagnetic shielding film has an unsatisfactory shielding effect, and cannot effectively shield electromagnetic interference in the circuit board, so that the circuit board still has a large electromagnetic interference problem in signal transmission.

In view of the above, it is desirable to develop a shielding film capable of effectively absorbing electromagnetic waves and solving the problem of electromagnetic interference.

SUMMERY OF THE UTILITY MODEL

The utility model aims at providing an electromagnetic shielding film can absorb the electromagnetic wave effectively to solve electromagnetic interference's problem.

In order to solve the technical problem, the utility model provides an electromagnetic shielding film, including shielding layer, first electromagnetic wave absorbed layer, first insulating layer and rete, first electromagnetic wave absorbed layer is located the shielding layer with between the first insulating layer, the rete is located first insulating layer is kept away from the one side of first electromagnetic wave absorbed layer.

Preferably, the electromagnetic shielding film further includes a second thermal insulation layer, and the second thermal insulation layer is disposed between the shielding layer and the first electromagnetic wave absorption layer.

Preferably, the electromagnetic shielding film further includes a second electromagnetic wave absorption layer, and the second electromagnetic wave absorption layer is disposed on a surface of the shielding layer away from the first electromagnetic wave absorption layer.

Preferably, the electromagnetic shielding film further includes a third thermal insulation layer, and the third thermal insulation layer is disposed on a surface of the second electromagnetic wave absorption layer away from the shielding layer.

Preferably, the electromagnetic shielding film further includes a fourth thermal insulation layer, and the fourth thermal insulation layer is disposed between the shielding layer and the second electromagnetic wave absorption layer.

Preferably, a conductive protrusion is disposed on a surface of the shielding layer close to the first electromagnetic wave absorption layer, and the conductive protrusion is embedded in the first electromagnetic wave absorption layer.

As a preferable scheme, a conductive bump is arranged on one surface of the shielding layer close to the first electromagnetic wave absorption layer, the conductive bump comprises a plurality of bumps, and the first electromagnetic wave absorption layer is arranged on a first region of the shielding layer and/or a second region of the conductive bump; the first region is a region where the conductive bump is not disposed in one surface of the shielding layer close to the first electromagnetic wave absorption layer, and the second region is a region formed between any two adjacent bumps in the conductive bump.

Preferably, the surface of the conductive bump is provided with conductive particles.

Preferably, the first electromagnetic wave absorption layer has conductivity, and the conductivity of the first electromagnetic wave absorption layer is smaller than the conductivity of the shielding layer; or the like, or, alternatively,

the first electromagnetic wave absorption layer has no conductivity.

Preferably, the second electromagnetic wave absorption layer has conductivity, and the conductivity of the second electromagnetic wave absorption layer is smaller than the conductivity of the shielding layer; or the like, or, alternatively,

the second electromagnetic wave absorption layer has no conductivity.

Preferably, at least one of the first electromagnetic wave absorption layer and the second electromagnetic wave absorption layer is composed of a binder and a wave-absorbing medium.

As a preferred scheme, the wave-absorbing medium is composed of any one of a carbon-series wave-absorbing material, an iron-series wave-absorbing material, a ceramic-series wave-absorbing material and a composite wave-absorbing material.

Preferably, the thickness of the first electromagnetic wave absorption layer is: 0.1-45 μm; the thickness of the second electromagnetic wave absorption layer is as follows: 0.1-45 μm.

Preferably, 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.

Preferably, the electromagnetic shielding film further includes an insulating layer, and the insulating layer is disposed on a surface of the shielding layer away from the first electromagnetic wave absorption layer.

Preferably, the electromagnetic shielding film further includes an insulating layer, and the insulating layer is disposed on a surface of the second electromagnetic wave absorption layer away from the shielding layer.

The utility model aims at providing a circuit board, be equipped with foretell electromagnetic shielding film in the circuit board, can absorb the electromagnetic wave effectively to solve electromagnetic interference's problem.

In order to solve the technical problem, an embodiment of the utility model provides a circuit board, including circuit board body and foretell electromagnetic shielding film, electromagnetic shielding film locates on the circuit board body.

Compared with the prior art, the utility model provides an electromagnetic shielding film and circuit board, through set up the first electromagnetic wave absorbed layer in the electromagnetic shielding film, make the electromagnetic shielding film have the function of absorbing the electromagnetic wave, therefore, when the electromagnetic shielding film is applied to the circuit board, the electromagnetic shielding film can absorb the produced electromagnetic wave of circuit board effectively, has realized the effective shielding to electromagnetic interference, thereby has avoided the circuit board to have great electromagnetic interference problem in signal transmission, has consequently guaranteed the normal work of circuit board; meanwhile, the first heat insulation layer is arranged between the first electromagnetic wave absorption layer and the adhesive film layer to absorb or insulate heat generated when the first electromagnetic wave absorption layer absorbs electromagnetic waves and heat generated by external devices, so that the problem that the electromagnetic shielding film is overheated and cracks due to the heat generated by the electromagnetic shielding film or the heat generated by the external devices is effectively solved, and the electromagnetic shielding film is ensured to have good electromagnetic shielding efficiency.

Drawings

Fig. 1 is a schematic structural diagram of an electromagnetic shielding film according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of another electromagnetic shielding film according to an embodiment of the present invention;

fig. 3 is a schematic structural diagram of an electromagnetic shielding film according to a second embodiment of the present invention;

fig. 4 is a schematic structural diagram of an electromagnetic shielding film according to a third embodiment of the present invention;

fig. 5 is a schematic structural diagram of an electromagnetic shielding film according to a fourth embodiment of the present invention;

fig. 6 is a schematic structural diagram of an electromagnetic shielding film according to a fifth embodiment of the present invention;

fig. 7 is a schematic structural diagram of an electromagnetic shielding film according to a sixth embodiment of the present invention;

fig. 8 is a schematic structural diagram of another electromagnetic shielding film according to a sixth embodiment of the present invention;

fig. 9 is a schematic structural diagram of an electromagnetic shielding film according to a seventh embodiment of the present invention;

fig. 10 is a schematic structural diagram of an electromagnetic shielding film according to an eighth embodiment of the present invention;

fig. 11 is a schematic structural diagram of another electromagnetic shielding film according to an eighth embodiment of the present invention;

fig. 12 is a schematic structural diagram of a circuit board according to a ninth embodiment of the present invention;

fig. 13 is a schematic flow chart of a manufacturing method of an electromagnetic shielding film according to an embodiment of the present invention.

Wherein, 1, a shielding layer; 11. a conductive bump; 111. a conductive particle; 12. a first region; 2. a first electromagnetic wave absorption layer; 3. a first insulating layer; 4. a glue film layer; 5. a second thermal insulation layer; 6. a second electromagnetic wave absorption layer; 7. a third thermal insulation layer; 8. a fourth thermal insulation layer; 9. an insulating layer; 10. the circuit board body.

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 some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

Example one

Combine fig. 1 and fig. 2 to show, the utility model discloses an electromagnetic shielding film of embodiment, including shielding layer 1, first electromagnetic wave absorbed layer 2, first insulating layer 3 and rete 4, first electromagnetic wave absorbed layer 2 is located shielding layer 1 with between the first insulating layer 3, rete 4 is located first insulating layer 3 is kept away from the one side of first electromagnetic wave absorbed layer 2.

It should be noted that the first electromagnetic wave absorption layer 2 has a function of absorbing electromagnetic waves, and is capable of absorbing electromagnetic wave energy projected to its surface and converting the electromagnetic wave energy into heat energy or other forms of energy through dielectric loss. The first insulating layer 3 has a function of absorbing heat or insulating heat. In addition, when the electromagnetic shielding film is applied to a circuit board, the electromagnetic shielding film is laminated with the circuit board.

In the embodiment of the present invention, the first electromagnetic wave absorbing layer 2 is disposed in the electromagnetic shielding film, so that the electromagnetic shielding film has a function of absorbing electromagnetic waves, and therefore, when the electromagnetic shielding film is applied to a circuit board, the electromagnetic shielding film can effectively absorb electromagnetic waves generated by the circuit board, thereby realizing effective shielding of electromagnetic interference, and thus avoiding the problem of large electromagnetic interference in signal transmission of the circuit board, and thus ensuring normal operation of the circuit board; meanwhile, the first heat insulation layer 3 is arranged between the first electromagnetic wave absorption layer 2 and the adhesive film layer 4 to absorb or isolate heat generated when the first electromagnetic wave absorption layer 2 absorbs electromagnetic waves and heat generated by external devices, so that the problem that the electromagnetic shielding film is overheated and cracks due to the heat generated by the electromagnetic shielding film or the heat generated by the external devices is effectively avoided, and the electromagnetic shielding film is ensured to have good electromagnetic shielding efficiency.

As can be understood, a plurality of signal lines are commonly disposed in the existing circuit board, and electromagnetic waves generated by the signal lines easily cause interference between the signal lines, thereby affecting signal transmission. This embodiment is through set up in the electromagnetic shielding film shielding layer 1 with first electromagnetic wave absorbed layer 2 makes when the electromagnetic shielding film is applied to when the circuit board, first electromagnetic wave absorbed layer 2 can absorb throw in it the produced electromagnetic wave of signal line in the circuit board, and the electromagnetic wave that is not absorbed completely is in the process shielding layer 1 is close to by reflection when the one side of first electromagnetic wave absorbed layer 2, thereby by first electromagnetic wave absorbed layer 2 secondary absorption has improved greatly the electromagnetic wave absorptivity of electromagnetic shielding film, and then realizes effective shielding to electromagnetic interference, has avoided effectively because the problem that influences signal transmission because produce the interference between the signal line in the circuit board, has consequently guaranteed the normal work of circuit board.

In a preferred embodiment, the first electromagnetic wave absorption layer 2 has conductivity, and the conductivity of the first electromagnetic wave absorption layer 2 is smaller than the conductivity of the shielding layer 1. By providing the first electromagnetic wave absorption layer 2 having conductivity in the electromagnetic shielding film, on the one hand, the first electromagnetic wave absorption layer 2 has a function of absorbing electromagnetic waves, which can absorb electromagnetic waves generated by signal lines in a circuit board to ensure the normal operation of the circuit board; on the other hand, the first electromagnetic wave absorption layer 2 also has a conductive function, and can be matched with the shielding layer 1 to realize electromagnetic shielding effectiveness.

It should be noted that, in the present embodiment, the proportional relationship between the conductivity of the first electromagnetic wave absorption layer 2 and the conductivity of the shielding layer 1 can be set according to the actual use condition; preferably, in the present embodiment, the conductivity of the first electromagnetic wave absorption layer 2 is 10% to 50% of the conductivity of the shielding layer 1.

In another preferred embodiment, the first electromagnetic wave absorption layer 2 has no electrical conductivity. By providing the first electromagnetic wave absorption layer 2 having no conductivity in the electromagnetic shielding film, the insertion loss during use of the wiring board can be reduced.

In the embodiment of the present invention, the first electromagnetic wave absorption layer 2 can be configured according to actual use conditions, and it is only necessary to ensure that it has a function of absorbing electromagnetic waves. Preferably, in this embodiment, the first electromagnetic wave absorption layer 2 is composed of an adhesive and the wave-absorbing medium. The wave-absorbing medium is composed of any one of a carbon-series wave-absorbing material, an iron-series wave-absorbing material, a ceramic-series wave-absorbing material and a composite wave-absorbing material. It should be noted that the carbon-based wave-absorbing material includes, but is not limited to, graphene, graphite, carbon black, carbon fiber, and carbon nanotube; the iron-based wave absorbing material comprises but is not limited to ferrite, a magnetic iron nano material, Fe-based alloy micro powder and an iron-based amorphous material; the ceramic-series wave-absorbing material comprises but is not limited to silicon carbide; the composite wave-absorbing material comprises but is not limited to a composite material formed by blending reduced graphene oxide/tin dioxide nano composite wave-absorbing material, manganese zinc ferrite/polypyrrole composite material, three-dimensional silver-graphene hybrid foam/epoxy resin composite material, rG0/Fe304@ Si02 composite material and soft magnetic powder and high molecular plastic. In addition, the wave absorbing medium can also be a conductive polymer, a chiral material, a plasma material, a porous hollow iron nanosphere, a self-skinning polyurethane lightweight material, a hollow sandwich microsphere metal sulfide and the like.

In the embodiment of the present invention, the concentration of the wave-absorbing medium in the first electromagnetic wave absorption layer 2 can be set according to the actual use condition. Preferably, in this embodiment, the concentration of the wave-absorbing medium in the first electromagnetic wave absorption layer 2 increases in the vertical direction. The concentration of the wave-absorbing medium in the first electromagnetic wave absorption layer 2 is increased in the vertical direction, so that the electromagnetic loss efficiency of the first electromagnetic wave absorption layer 2 is improved, the electromagnetic waves projected onto the first electromagnetic wave absorption layer 2 can be absorbed to the maximum extent, and the effective shielding of electromagnetic interference is further ensured.

Further, in this embodiment, the concentration of the wave-absorbing medium in the first electromagnetic wave absorption layer 2 gradually increases along the first direction; wherein the first direction is a direction from the first electromagnetic wave absorption layer 2 to the shielding layer 1 perpendicularly.

It should be noted that, because the concentration of the wave-absorbing medium in the first electromagnetic wave absorption layer 2 gradually increases along the first direction, when the electromagnetic shielding film is applied to a circuit board, the electromagnetic wave generated by the circuit board is located on one side of the first electromagnetic wave absorption layer 2 close to the adhesive film layer 3, that is, the electromagnetic wave generated by the circuit board is incident from the side of the first electromagnetic wave absorption layer 2 with the lower concentration of the wave-absorbing medium, and is thus gradually absorbed by the first electromagnetic wave absorption layer 2; and the electromagnetic wave which is not completely absorbed is reflected when passing through the first electromagnetic wave absorption layer 2 near one surface of the shielding layer 1, so that the electromagnetic wave is secondarily absorbed by the first electromagnetic wave absorption layer 2, and the electromagnetic wave absorption rate of the electromagnetic shielding film is greatly improved.

In another preferred embodiment, the first electromagnetic wave absorption layer 2 includes a plurality of stacked first electromagnetic wave absorption sublayers, and the electromagnetic wave absorption rates of the plurality of first electromagnetic wave absorption sublayers increase in the vertical direction. Wherein the first electromagnetic wave absorption sublayer has a function of absorbing electromagnetic waves.

Further, the electromagnetic wave absorption rates of the plurality of first electromagnetic wave absorption sublayers sequentially increase along the first direction.

In the embodiment of the present invention, since the electromagnetic wave absorption rates of the plurality of first electromagnetic wave absorption sublayers increase gradually along the first direction, when the electromagnetic shielding film is applied to a circuit board, the electromagnetic wave generated by the circuit board is located at a side of the first electromagnetic wave absorption layer 2 close to the adhesive film layer 4, that is, the electromagnetic wave generated by the circuit board is incident from a side of the first electromagnetic wave absorption sublayer with a lower electromagnetic wave absorption rate, and is absorbed by the first electromagnetic wave absorption layer 2 step by step; the electromagnetic wave which is not completely absorbed is reflected when passing through the first electromagnetic wave absorption layer 2 near one surface of the shielding layer 1, so that the electromagnetic wave is secondarily absorbed by the first electromagnetic wave absorption layer 2, and the electromagnetic wave absorption rate of the whole electromagnetic shielding film is greatly improved.

It should be noted that, in the first electromagnetic wave absorption layer 2, the electromagnetic wave absorption rate of each of the first electromagnetic wave absorption sublayers may be set to be different from each other, so for two adjacent first electromagnetic wave absorption sublayers, the electromagnetic wave absorption rate of the first electromagnetic wave absorption sublayer close to the shielding layer 1 is greater than that of the first electromagnetic wave absorption sublayer far from the shielding layer 1. Of course, in the first electromagnetic wave absorption layer 2, the electromagnetic wave absorption rates of some of the first electromagnetic wave absorption sublayers may also be set to be the same, and it is only necessary to ensure that the electromagnetic wave absorption rates of a plurality of the first electromagnetic wave absorption sublayers are in an increasing trend in the vertical direction; for example, two first electromagnetic wave absorption sub-layers having the same electromagnetic wave absorption rate are stacked as a single integrated structure, the first electromagnetic wave absorption layer is formed by stacking a plurality of the integrated structures, and the electromagnetic wave absorption rates of the plurality of the integrated structures increase in the vertical direction.

It can be understood that, here, it is only a specific implementation manner that the electromagnetic wave absorption rate of the plurality of first electromagnetic wave absorption sublayers increases in the vertical direction, and the electromagnetic wave absorption rate of the plurality of first electromagnetic wave absorption sublayers in this embodiment may also be set to be an increasing trend along the first direction, and the embodiment of the present invention does not limit the specific implementation manner that the electromagnetic wave absorption rate of the plurality of first electromagnetic wave absorption sublayers increases in the vertical direction.

In addition, the thickness of the first electromagnetic wave absorption layer 2 may be set according to actual use. In order to ensure that the first electromagnetic wave absorption layer 2 can absorb the electromagnetic wave generated by the circuit board, the thickness of the first electromagnetic wave absorption layer 2 in the embodiment is preferably 0.1 μm to 45 μm. In addition, in this embodiment, the outer surface of the first electromagnetic wave absorption layer 2 may be a flat surface, or may be a non-flat surface, which is not limited in this embodiment.

In the embodiment of the present invention, the shielding layer 1 includes a first surface contacting with the first electromagnetic wave absorption layer 2, and the first surface of the shielding layer 1 may be a surface of any shape, for example, a flat surface as shown in fig. 1, or an uneven surface as shown in fig. 2; in addition, the first surface of the shielding layer 1 may be a regular surface or an irregular surface.

In the embodiment of the present invention, the shielding layer 1 further includes a second surface disposed opposite to the first surface. It should be noted that the second surface of the shielding layer 1 may be a surface of any shape, for example, a flat surface as shown in fig. 1, or a non-flat surface; in addition, the second surface of the shielding layer 1 may be a regular surface or an irregular surface. The drawings of the present invention only illustrate the second surface of the shielding layer 1 as a flat surface, and the second surface of the shielding layer 1 in any other shape is within the protection scope of the present invention.

In the embodiment of the present invention, the thickness of the shielding layer 1 can be set according to the actual use condition; preferably, the thickness of the shielding layer 1 is 0.1 μm to 45 μm. In addition, in order to ensure that the shielding layer 1 has good conductivity, 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; 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 addition, the shielding layer 1 in the drawings of the present embodiment may have a single-layer structure or a multi-layer structure. In addition, the shielding layer 1 of the present embodiment can be arranged in a grid shape, a foaming shape, etc. according to the requirements of actual production and application.

In the embodiment of the present invention, the material of the first thermal insulation layer 3 may be set according to actual use conditions. Preferably, the first thermal insulation layer 3 in this embodiment is made of a heat dissipation material or a thermal insulation material. In addition, it should be noted that the outer surface of the first thermal insulation layer 3 may be a flat surface, or may be a non-flat surface, which is not limited in this embodiment.

In the embodiment of the present invention, one of the structures of the adhesive film layer 4 is specifically represented as: the adhesive layer 4 includes an adhesive layer containing conductive particles. The adhesive film layer 4 has an adhesive effect by making the adhesive film layer 4 include an adhesive layer containing conductive particles, so that the circuit board and the electromagnetic shielding film are tightly adhered, and the adhesive film layer 4 also has a conductive function, so that when the shielding layer 1 has the conductive protrusions 11, the shielding layer 1 can be matched with the shielding layer 1, and interference electrons can be rapidly introduced into the ground layer of the circuit 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, the other structure of the adhesive film layer 4 is specifically represented as: the adhesive layer 4 includes an adhesive layer containing no conductive particles. The adhesive film layer 4 has an adhesive effect by enabling the adhesive film layer 4 to include an adhesive layer without containing conductive particles, so that the circuit board and the electromagnetic shielding film are tightly adhered, and meanwhile, because the adhesive film layer 4 includes an adhesive layer without containing conductive particles, the insertion loss of the circuit board in the using process is reduced, the shielding efficiency is improved, and meanwhile, the bending property of the circuit board is improved.

In addition, the thickness of the adhesive film layer 4 in this embodiment is 1 μm to 80 μm. The material used for the glue film layer 4 is selected from the following materials: modified epoxy resins, acrylic resins, modified rubbers, and modified thermoplastic polyimides. In addition, it should be noted that the outer surface of the adhesive film layer 4 may be a flat surface or a non-flat surface, which is not limited in this embodiment.

Example two

As shown in fig. 3, the electromagnetic shielding film in this embodiment is different from the first embodiment in that the electromagnetic shielding film further includes a second thermal insulation layer 5, and the second thermal insulation layer 5 is disposed between the shielding layer 1 and the first electromagnetic wave absorption layer 2.

The second insulating layer 5 has a function of absorbing heat or insulating heat. This embodiment is through shielding layer 1 with set up between the first electromagnetic wave absorbing layer 2 second insulating layer 5 to absorb or completely cut off first electromagnetic wave absorbing layer 2 is produced heat when absorbing the electromagnetic wave, thereby avoids electromagnetic shielding film self produced heat influences electromagnetic shielding film, and then has further guaranteed electromagnetic shielding film's electromagnetic shielding effectiveness.

In the embodiment of the present invention, the material of the second thermal insulation layer 5 may be set according to actual use conditions. Preferably, the second thermal insulation layer 5 in this embodiment is made of a heat dissipation material or a thermal insulation material. In addition, it should be noted that the outer surface of the second thermal insulation layer 5 may be a flat surface, or may be a non-flat surface, which is not limited in this embodiment.

In addition, when the electromagnetic shielding film includes the first thermal insulation layer 3 and the second thermal insulation layer 5, the first electromagnetic wave absorption layer 2 is disposed between the first thermal insulation layer 3 and the second thermal insulation layer 5, and the first thermal insulation layer 3 and the second thermal insulation layer 5 are matched with each other, so that the electromagnetic shielding film has an effect of well absorbing or isolating heat generated when the first electromagnetic wave absorption layer 2 absorbs electromagnetic waves, so as to prevent the heat generated by the first electromagnetic wave absorption layer 2 from affecting the electromagnetic shielding film.

In the embodiment of the present invention, other structures and working principles of the electromagnetic shielding film of the present embodiment are the same as those of the first embodiment, and are not described herein.

EXAMPLE III

As shown in fig. 4, the electromagnetic shielding film in this embodiment is different from the first and second embodiments in that the electromagnetic shielding film further includes a second electromagnetic wave absorption layer 6, and the second electromagnetic wave absorption layer 6 is disposed on a side of the shielding layer 1 away from the first electromagnetic wave absorption layer 2.

It should be noted that the second electromagnetic wave absorption layer 6 has a function of absorbing electromagnetic waves, and is capable of absorbing electromagnetic wave energy projected to its surface and converting the electromagnetic wave energy into heat energy or other forms of energy through dielectric loss.

The embodiment of the utility model provides an in, through keep away from shielding layer 1 set up in the one side of first electromagnetic wave absorbed layer 2 second electromagnetic wave absorbed layer 6 makes and works as when the electromagnetic shielding film is applied to the circuit board, the electromagnetic shielding film can pass through second electromagnetic wave absorbed layer 6 absorbs and comes from the outside electromagnetic wave of circuit board to further realized effectively shielding electromagnetic interference, guaranteed the normal work of circuit board.

It can be understood that, the circuit board is applied to electronic devices such as smart phones and tablet computers, and these electronic devices are usually provided with an antenna, and electromagnetic waves generated by the antenna also affect signal transmission in the circuit board. Therefore, by arranging the second electromagnetic wave absorption layer 6 on the side of the shielding layer 1 away from the first electromagnetic wave absorption layer 2, when the electromagnetic shielding film is applied to the circuit board, the second electromagnetic wave absorption layer 6 can absorb the electromagnetic waves generated by the antenna and other devices outside the circuit board, and the electromagnetic waves which are not completely absorbed are reflected when passing through the side of the shielding layer 1 close to the second electromagnetic wave absorption layer 6, so that the electromagnetic waves are secondarily absorbed by the second electromagnetic wave absorption layer 6, the electromagnetic wave absorption rate of the electromagnetic shielding film is greatly improved, the interference of the electromagnetic waves generated by the external devices on the circuit board is effectively avoided, and the normal signal transmission of the circuit board is further ensured.

In the embodiment of the present invention, the second electromagnetic wave absorption layer 6 can be configured according to actual use conditions, and it is only necessary to ensure that it has a function of absorbing electromagnetic waves. Preferably, in this embodiment, the second electromagnetic wave absorption layer 6 is composed of an adhesive and a wave-absorbing medium. The wave-absorbing medium is composed of any one of a carbon-series wave-absorbing material, an iron-series wave-absorbing material, a ceramic-series wave-absorbing material and a composite wave-absorbing material. It should be noted that the carbon-based wave-absorbing material includes, but is not limited to, graphene, graphite, carbon black, carbon fiber, and carbon nanotube; the iron-based wave absorbing material comprises but is not limited to ferrite, a magnetic iron nano material, Fe-based alloy micro powder and an iron-based amorphous material; the ceramic-series wave-absorbing material comprises but is not limited to silicon carbide; the composite wave-absorbing material comprises but is not limited to a composite material formed by blending reduced graphene oxide/tin dioxide nano composite wave-absorbing material, manganese zinc ferrite/polypyrrole composite material, three-dimensional silver-graphene hybrid foam/epoxy resin composite material, rG0/Fe304@ Si02 composite material and soft magnetic powder and high molecular plastic. In addition, the wave absorbing medium can also be a conductive polymer, a chiral material, a plasma material, a porous hollow iron nanosphere, a self-skinning polyurethane lightweight material, a hollow sandwich microsphere metal sulfide and the like.

In the embodiment of the present invention, the concentration of the wave absorbing medium in the second electromagnetic wave absorbing layer 6 can be set according to the actual use condition. Preferably, in this embodiment, the concentration of the wave-absorbing medium in the second electromagnetic wave absorption layer 6 increases in the vertical direction. The concentration of the wave-absorbing medium in the second electromagnetic wave absorption layer 6 is increased in the vertical direction, so that the electromagnetic loss efficiency of the second electromagnetic wave absorption layer 6 is improved, the electromagnetic waves projected onto the second electromagnetic wave absorption layer 6 can be absorbed to the maximum extent, and the effective shielding of electromagnetic interference is further ensured.

Further, in this embodiment, the concentration of the wave-absorbing medium in the second electromagnetic wave absorption layer 6 gradually increases along a second direction; wherein the second direction is a direction perpendicularly directed to the shielding layer 1 by the second electromagnetic wave absorption layer 6.

In the embodiment of the present invention, since the concentration of the wave-absorbing medium in the second electromagnetic wave absorbing layer 6 gradually increases along the second direction, when the electromagnetic shielding film is applied to a circuit board, the electromagnetic wave from the outside of the circuit board is located on the side of the second electromagnetic wave absorbing layer 6 away from the shielding layer 1, that is, the electromagnetic wave from the outside of the circuit board is incident from the side of the second electromagnetic wave absorbing layer 6 with lower concentration of the wave-absorbing medium, and is gradually absorbed by the second electromagnetic wave absorbing layer 6; and the electromagnetic wave which is not completely absorbed is reflected when passing through the side of the second electromagnetic wave absorption layer 6 close to the shielding layer 1, so that the electromagnetic wave is secondarily absorbed by the second electromagnetic wave absorption layer 6, and the electromagnetic wave absorption rate of the electromagnetic shielding film is greatly improved.

In another preferred embodiment, the second electromagnetic wave absorption layer 6 includes a plurality of stacked second electromagnetic wave absorption sublayers, and the electromagnetic wave absorption rates of the plurality of second electromagnetic wave absorption sublayers increase in the vertical direction. Wherein the second electromagnetic wave absorption sublayer has a function of absorbing electromagnetic waves.

Further, the electromagnetic wave absorption rates of the plurality of second electromagnetic wave absorption sublayers sequentially increase along the second direction.

In the embodiment of the present invention, since the electromagnetic wave absorption rates of the plurality of second electromagnetic wave absorption sublayers sequentially increase along the second direction, when the electromagnetic shielding film is applied to a circuit board, electromagnetic waves from outside the circuit board are located on a side of the second electromagnetic wave absorption layer 6 away from the shielding layer 1, that is, electromagnetic waves from outside the circuit board are incident from a side of the second electromagnetic wave absorption sublayer having a lower electromagnetic wave absorption rate, and are absorbed by the second electromagnetic wave absorption layer 6 step by step; and the electromagnetic wave which is not completely absorbed is reflected when passing through the side of the second electromagnetic wave absorption layer 6 close to the shielding layer 1, so that the electromagnetic wave is secondarily absorbed by the second electromagnetic wave absorption layer 6, and the electromagnetic wave absorption rate of the electromagnetic shielding film is greatly improved.

It can be understood that, here, only one specific implementation manner that the electromagnetic wave absorption rates of the plurality of second electromagnetic wave absorption sublayers increase in the vertical direction is adopted, in this embodiment, the electromagnetic wave absorption rates of the plurality of second electromagnetic wave absorption sublayers may also be set to be in an increasing trend along the second direction, and the embodiment of the present invention does not limit the specific implementation manner that the electromagnetic wave absorption rates of the plurality of second electromagnetic wave absorption sublayers increase in the vertical direction.

In a preferred embodiment, the second electromagnetic wave absorption layer 6 has conductivity, and the conductivity of the second electromagnetic wave absorption layer 6 is smaller than the conductivity of the shielding layer 1. By providing the second electromagnetic wave absorption layer 6 having conductivity in the electromagnetic shielding film, on the one hand, the second electromagnetic wave absorption layer 6 has a function of absorbing electromagnetic waves, which can absorb electromagnetic waves from the outside of the circuit board, to further ensure the normal operation of the circuit board; on the other hand, the second electromagnetic wave absorption layer 6 also has a conductive function, and can be matched with the shielding layer 1 to realize shielding effectiveness.

It should be noted that, in the present embodiment, the proportional relationship between the conductivity of the second electromagnetic wave absorption layer 6 and the conductivity of the shielding layer 1 can be set according to the actual use condition; preferably, in the present embodiment, the conductivity of the second electromagnetic wave absorption layer 6 is 10% to 50% of the conductivity of the shielding layer 1.

In another preferred embodiment, the second electromagnetic wave absorption layer 6 has no electrical conductivity. By providing the second electromagnetic wave absorption layer 6 having no conductivity in the electromagnetic shielding film, the insertion loss during use of the wiring board can be reduced.

In addition, the thickness of the second electromagnetic wave absorption layer 6 may be set according to actual use. In order to ensure that the second electromagnetic wave absorption layer 6 can absorb electromagnetic waves from the outside of the wiring board, the thickness of the second electromagnetic wave absorption layer 6 in this embodiment is preferably 0.1 μm to 45 μm. In addition, in this embodiment, the outer surface of the second electromagnetic wave absorption layer 6 may be a flat surface, or may be a non-flat surface, which is not limited in this embodiment.

In the embodiment of the present invention, other structures and working principles of the electromagnetic shielding film of the present embodiment are the same as those of the first embodiment and the second embodiment, and are not further described herein.

Example four

As shown in fig. 5, the electromagnetic shielding film in this embodiment is different from the third embodiment in that the electromagnetic shielding film further includes a third thermal insulation layer 7, and the third thermal insulation layer 7 is disposed on a side of the second electromagnetic wave absorption layer 6 away from the shielding layer 1.

The third insulating layer 7 has a function of absorbing heat or insulating heat. In this embodiment, the third thermal insulation layer 7 is disposed on a side of the second electromagnetic wave absorption layer 6 away from the shielding layer 1, so as to absorb or isolate heat generated when the second electromagnetic wave absorption layer 6 absorbs electromagnetic waves and heat generated by an external device, thereby avoiding the problem that the electromagnetic shielding film is overheated and cracked due to the heat generated by the electromagnetic shielding film itself or the heat generated by the external device, and further ensuring that the electromagnetic shielding film has good electromagnetic shielding performance.

In the embodiment of the present invention, the material of the third thermal insulation layer 7 may be set according to actual use conditions. Preferably, the third thermal insulation layer 7 in this embodiment is made of a heat dissipation material or a thermal insulation material. In addition, it should be noted that the outer surface of the third thermal insulation layer 7 may be a flat surface, or may be a non-flat surface, which is not limited in this embodiment.

In the embodiment of the present invention, other structures and working principles of the electromagnetic shielding film of the present embodiment are the same as those of the embodiment, and are not further described herein.

EXAMPLE five

As shown in fig. 6, the electromagnetic shielding film in the present embodiment is different from the third and fourth embodiments in that the electromagnetic shielding film further includes a fourth thermal insulation layer 8, and the fourth thermal insulation layer 8 is disposed between the shielding layer 1 and the second electromagnetic wave absorption layer 6.

Note that the fourth insulating layer 8 has a function of absorbing heat or insulating heat. This embodiment is through shielding layer 1 with set up between second electromagnetic wave absorbing layer 6 fourth insulating layer 8 to absorb or completely cut off the produced heat when second electromagnetic wave absorbing layer 6 absorbs the electromagnetic wave, thereby avoid the produced heat of electromagnetic shielding film self influences the electromagnetic shielding film, and then further guaranteed the electromagnetic shielding film has good electromagnetic shielding effectiveness.

In the embodiment of the present invention, the material of the fourth thermal insulation layer 8 may be set according to actual use conditions. Preferably, the fourth thermal insulation layer 8 in this embodiment is made of a heat dissipation material or a thermal insulation material. In addition, it should be noted that the outer surface of the fourth thermal insulation layer 8 may be a flat surface, or may be a non-flat surface, which is not limited in this embodiment.

In addition, when the electromagnetic shielding film includes the third thermal insulation layer 7 and the fourth thermal insulation layer 8, the second electromagnetic wave absorption layer 6 is disposed between the third thermal insulation layer 7 and the fourth thermal insulation layer 8, and the third thermal insulation layer 7 and the fourth thermal insulation layer 8 are matched with each other, so that the electromagnetic shielding film has an effect of well absorbing or isolating heat generated when the second electromagnetic wave absorption layer 6 absorbs electromagnetic waves, so as to prevent the heat generated by the second electromagnetic wave absorption layer 6 from affecting the electromagnetic shielding film.

In the embodiment of the present invention, other structures and working principles of the electromagnetic shielding film of this embodiment are the same as those of the third or fourth embodiment, and are not described herein.

EXAMPLE six

Referring to fig. 7 and 8, the electromagnetic shielding film in the present embodiment is different from the first embodiment in that a conductive protrusion 11 is disposed on a surface of the shielding layer 1 close to the first electromagnetic wave absorption layer 2, and the conductive protrusion 11 is embedded in the first electromagnetic wave absorption layer 2.

It can be understood that the embedding of the conductive bump 11 into the first electromagnetic wave absorption layer 2 includes two cases: (1) the conductive bump 11 is located at a certain distance from one surface of the first electromagnetic wave absorption layer 2 close to the first thermal insulation layer 3, that is, the conductive bump 11 is completely located inside the first electromagnetic wave absorption layer 2; (2) the conductive bump 11 penetrates the first electromagnetic wave absorption layer 2. Under the condition that the conductive bump 11 is completely positioned inside the first electromagnetic wave absorption layer 2, the first electromagnetic wave absorption layer 2 has fluidity at a certain pressing temperature, so that when the electromagnetic shielding film is pressed with the circuit board, the conductive bump 11 can sequentially pierce through the first electromagnetic wave absorption layer 2, the first heat insulation layer 3 and the glue film layer 4 so as to be connected with the ground layer of the circuit board, and then the interference charges accumulated in the electromagnetic shielding film are led out, thereby further improving the shielding effectiveness of the electromagnetic shielding film; and under the condition that the conductive bump 11 penetrates through the first electromagnetic wave absorption layer 2, the first electromagnetic wave absorption layer 2 may have no fluidity or fluidity at a certain pressing temperature, so that when the electromagnetic shielding film is pressed against the circuit board, the conductive bump 11 penetrates through the first thermal insulation layer 3 and the glue film layer 4 so as to be connected with the ground layer of the circuit board.

It should be noted that, the conductive bump 11 may also sequentially pass through the first electromagnetic wave absorption layer 2 and the first thermal insulation layer 3 and be embedded in the adhesive film layer 4, which is not limited by the present invention.

In a preferred embodiment, as shown in fig. 8, in order to improve the piercing strength of the conductive bump 11, the surface of the conductive bump 11 is provided with conductive particles 111. Through the surface of the conductive protrusion 11 is provided with the conductor particles 111, the piercing force of the conductive protrusion 11 is increased, so that the electromagnetic shielding film and the circuit board are further ensured to be pressed together, the conductive protrusion 11 can smoothly pierce the first electromagnetic wave absorption layer 2, the first thermal insulation layer 3 and the glue film layer 4 and is connected with the ground layer of the circuit, and the normal conduction of interference charges is further ensured.

In the embodiment of the present invention, the height of the conductor particles 111 can be set according to actual use conditions; in order to ensure that the piercing strength of the conductive bump 11 can be increased, the height of the conductive particles in this embodiment is preferably 0.1 μm to 30 μm.

In an embodiment of the present invention, the conductive particles 111 include one or more of metal particles, carbon nanotube particles, and ferrite particles. Wherein the metal particles comprise 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.

In the embodiment of the present invention, the shape of the conductor particles 111 is illustrated only for an example, and due to differences in process means and parameters, the conductor particles 111 may also have other shapes such as cluster, ice, stalactite, and dendritic shapes. The conductor particles 111 in the present invention are not limited by the shapes and the drawings, and any conductor particles having piercing and conductive functions are within the protection scope of the present invention.

In the embodiment of the present invention, it should be noted that the conductive particles 111 may be the same as or different from the conductive bumps 11. Therefore, in a specific implementation, the conductive bump 11 may be formed first, and then the conductive particles 111 may be formed on the outer surface of the conductive bump 11 through another process. Of course, the conductive bumps 11 and the conductive particles 111 may be formed as a single structure by a single molding process.

Further, it should be noted that the structure of the conductive bump 11 shown in the drawings is merely exemplary. The present invention provides a conductive protrusion 11 is not limited by the shape of the figure and the above shape, and is provided with a conductive protrusion that pierces through and has a conductive function, which is within the protection scope of the present invention.

In the embodiment of the present invention, the shielding layer 1 may be formed first, and then the conductive protrusion 11 is formed on the first surface of the shielding layer 1 by other processes, as shown in fig. 7. Of course, the shielding layer 1 and the conductive bump 11 may be an integral structure formed by a one-step molding process.

EXAMPLE seven

As shown in fig. 9, the electromagnetic shielding film in this embodiment is different from the sixth embodiment in that a conductive protrusion 11 is disposed on a surface of the shielding layer 1 close to the first electromagnetic wave absorption layer 2, the conductive protrusion 11 includes a plurality of protrusions, and the first electromagnetic wave absorption layer 2 is disposed on a first region 12 of the shielding layer 1 and/or a second region of the conductive protrusion 11; the first region 12 is a region where the conductive bump 11 is not disposed on one surface of the shielding layer 1 close to the first electromagnetic wave absorption layer 2, and the second region is a region formed between any two adjacent bumps in the conductive bump 11.

It can be understood that the first electromagnetic wave absorption layer 2 is disposed on the first region 12 of the shielding layer 1 and/or the second region of the conductive bump 11, and at this time, the first electromagnetic wave absorption layer 2 does not cover the conductive bump 11, so that when the electromagnetic shielding film is laminated with the circuit board, the conductive bump 11 can be connected with the ground layer of the circuit board only by piercing the first thermal insulation layer 3 and the adhesive film layer 4. Specifically, the arrangement of the conductive bump 11 specifically includes two cases: (1) the height of the conductive bump 11 is less than or equal to the thickness of the first electromagnetic wave absorption layer 2; (2) the height of the conductive bump 11 is greater than the thickness of the first electromagnetic wave absorption layer 2. Under the condition that the height of the conductive bump 11 is less than or equal to the thickness of the first electromagnetic wave absorption layer 2, the first electromagnetic wave absorption layer 2 has fluidity at a certain pressing temperature, so that when the electromagnetic shielding film is pressed with the circuit board, the conductive bump 11 can pierce the first thermal insulation layer 3 and the adhesive film layer 4 to be connected with the ground layer of the circuit board; and under the condition that the height of the conductive bump 11 is greater than the thickness of the first electromagnetic wave absorption layer 2, the first electromagnetic wave absorption layer 2 may have no fluidity or fluidity at a certain pressing temperature, so that when the electromagnetic shielding film is pressed against the circuit board, the conductive bump 11 can directly pierce the first thermal insulation layer 3 and the adhesive film layer 4, thereby being connected with the ground layer of the circuit board.

It should be noted that the first electromagnetic wave absorption layer 2 is disposed in the first region of the shielding layer 1 and/or the second region of the conductive bump 11 specifically includes three cases: (1) the first electromagnetic wave absorption layer 2 is only provided in the first region 12; (2) the first electromagnetic wave absorption layer 2 is only arranged in the second region; (3) the first electromagnetic wave absorption layer 2 is provided in the first region 12 and the second region. One specific implementation manner of the first electromagnetic wave absorption layer 2 disposed on the first region 12 of the shielding layer 1 is as follows: a through hole penetrating through the upper and lower surfaces of the first electromagnetic wave absorption layer 2 is provided, and the conductive bump 11 penetrates through the through hole, so that the first electromagnetic wave absorption layer 2 is only provided in a region where the conductive bump 11 is not provided in one surface of the shielding layer 1 close to the first electromagnetic wave absorption layer 2. In addition, another specific implementation manner of the first electromagnetic wave absorption layer 2 disposed on the first region 12 of the shielding layer 1 is as follows: the first electromagnetic wave absorption layer 2 is composed of a plurality of absorption sublayers, and each absorption sublayer is respectively arranged on the first electromagnetic wave absorption layer 2 arranged on the first region 12 of the shielding layer 1.

In the embodiment of the present invention, by disposing the first electromagnetic wave absorption layer 2 on the first region 12 of the shielding layer 1 and/or the second region of the conductive bump 11, it is ensured that the electromagnetic shielding film can absorb the electromagnetic wave generated by the circuit board through the first electromagnetic wave absorption layer 2, so as to achieve effective shielding of electromagnetic interference; on the other hand, when the electromagnetic screen film is laminated with the circuit board, the conductive bump 11 can be connected with the ground layer of the circuit board only by penetrating the first heat-insulating layer 3 and the adhesive film layer 4 without penetrating the first electromagnetic wave absorption layer 2, so that the requirement on the penetrating strength of the conductive bump 11 is reduced, and the structure of the conductive bump 11 is simplified.

In addition, in this embodiment, the first electromagnetic wave absorption layer 2 and the first heat insulation layer 3 which are laminated may be formed as an integral structure, and the integral structure may be provided in the first region 12; at this time, the first electromagnetic wave absorption layer 2 and the first thermal insulation layer 3 do not cover the conductive protrusion 11, so that when the electromagnetic screen film is laminated with the circuit board, the conductive protrusion 11 can be connected with the ground layer of the circuit board only by piercing the adhesive film layer 4. In addition, when electromagnetic shielding film still includes second insulating layer 5, also can adopt above-mentioned mode to set up in first region 12, the utility model discloses no longer describe herein.

In a preferred embodiment, in order to improve the piercing strength of the conductive bump 11, the surface of the conductive bump 11 is provided with conductive particles 111. Through the surface of electrically conductive protruding 11 sets up conductor granule 111 has increased electrically conductive protruding 11 impales the dynamics to further guaranteed electromagnetic shielding membrane with during the circuit board pressfitting, electrically conductive protruding 11 can pierce smoothly glue film layer 4 and with the stratum of circuit is connected, and then guarantees the normal derivation of disturbing charge. The shape and structure of the conductive particles 111 can be specifically described with reference to the description of the second embodiment, and the description of this embodiment is not repeated herein.

In the embodiment of the present invention, other structures and working principles of the electromagnetic shielding film of the present embodiment are the same as those of the sixth embodiment, and are not described herein.

Example eight

As shown in fig. 10, this embodiment provides an electromagnetic shielding film, which is different from the first and second embodiments in that the electromagnetic shielding film further includes an insulating layer 9, and the insulating layer 9 is disposed on a side of the shielding layer 1 away from the first electromagnetic wave absorption layer 2.

As shown in fig. 11, this embodiment further provides another electromagnetic shielding film, which is different from the third and fifth embodiments in that the electromagnetic shielding film further includes an insulating layer 9, and the insulating layer 9 is disposed on a side of the second electromagnetic wave absorption layer 6 away from the shielding layer 1.

The present embodiment further provides another electromagnetic shielding film, which is different from the fourth embodiment in that the electromagnetic shielding film further includes an insulating layer 9, and the insulating layer 9 is disposed on a surface of the third thermal insulating layer 7 away from the second electromagnetic wave absorption layer 6.

In the embodiment of the present invention, the insulating layer 9 is disposed in the electromagnetic shielding film, so that the electromagnetic shielding film is insulated from the surrounding environment or the adjacent conductors, thereby ensuring the shielding effectiveness of the electromagnetic shielding film.

In the embodiment of the present invention, other structures and working principles of the electromagnetic shielding film of the present embodiment are the same as those of the first to fifth embodiments, and are not further described herein.

Example nine

As shown in fig. 12, the embodiment of the present invention further provides a circuit board, including a circuit board body 6 and any one of the first to eighth embodiments of the electromagnetic shielding film, where the electromagnetic shielding film is disposed on the circuit board body 6.

It should be noted that, when the conductive bumps 11 are disposed in the electromagnetic shielding film, the conductive bumps 11 of the electromagnetic shielding film pierce the adhesive film layer 4 and are connected to the ground layer in the circuit board body 6.

In the embodiment of the present invention, the conductive bumps 11 in the electromagnetic shielding film may all contact with the ground layer of the circuit board body 6, or may partially contact with the ground layer of the circuit board body 6, which is not limited in this embodiment.

In addition, for the implementation of the electromagnetic shielding film, reference may be made to the descriptions of the first to eighth embodiments, which are not repeated herein.

In the embodiment of the present invention, the type of the circuit board body 6 can be set according to the actual use condition; preferably, the circuit board body 6 in this embodiment is one of a flexible single-sided circuit board, a flexible double-sided circuit board, a flexible multilayer board, and a rigid-flex printed circuit board.

In addition, in the specific implementation, when the circuit board is applied to an electronic device, a free grounding film may be further disposed, so that one surface of the free grounding film is electrically connected to a housing of the electronic device, and the other surface of the free grounding film is electrically connected to the electromagnetic shielding film, thereby conducting out interference charges accumulated in the electromagnetic shielding film.

In the embodiment of the present invention, the circuit board is composed of the circuit board body 6 and the electromagnetic shielding film, so that the electromagnetic wave generated by the circuit board can be absorbed by the first electromagnetic wave absorption layer 2 arranged between the shielding layer 1 and the adhesive film layer 3, thereby realizing effective shielding of electromagnetic interference, and effectively avoiding the problem of large electromagnetic interference in signal transmission of the circuit board, thereby ensuring normal operation of the circuit board; meanwhile, the first heat insulation layer 3 is arranged between the first electromagnetic wave absorption layer 2 and the adhesive film layer 4, so that heat generated when the first electromagnetic wave absorption layer 2 absorbs electromagnetic waves and heat generated by external devices can be absorbed or isolated, the problem that the electromagnetic shielding film is overheated and cracks due to the heat generated by the electromagnetic shielding film or the heat generated by the external devices is solved, and the electromagnetic shielding film has good electromagnetic shielding efficiency.

Example ten

The embodiment of the utility model provides an electromagnetic shielding film' S preparation method, this method is applicable to the electromagnetic shielding film of preparation embodiment one, the method includes following step S11-S14:

and S11, manufacturing and forming a shielding layer.

Wherein the shielding layer is formed in step S11 by:

forming a protective film layer on a carrier film, the shielding layer being formed on the protective film layer; or

The method comprises the steps of forming a peelable layer on a carrier film, forming the shielding layer on a surface of the peelable layer, and peeling the carrier film after forming a protective film layer on a side of the shielding layer remote from the peelable layer.

The shielding layer can be formed by adopting an electroless plating mode, PVD, CVD, evaporation plating, sputtering plating, electroplating or a composite process thereof.

And S12, forming a first electromagnetic wave absorption layer on one surface of the shielding layer.

And S13, forming a first heat insulation layer on one surface of the first electromagnetic wave absorption layer far away from the shielding layer.

And S14, forming an adhesive film layer on one surface of the first heat insulation layer far away from the first electromagnetic wave absorption layer.

In step S14, the forming a glue film layer on a surface of the first thermal insulation layer away from the first electromagnetic wave absorption layer specifically includes:

coating an adhesive film layer on a release film, and then transferring the adhesive film layer to one surface, away from the first electromagnetic wave absorption layer, of the first heat insulation layer in a pressing manner, so that the adhesive film layer is formed on one surface, away from the first electromagnetic wave absorption layer, of the first heat insulation layer; or

And directly coating an adhesive film layer on one surface of the first heat insulation layer, which is far away from the first electromagnetic wave absorption layer, so that the adhesive film layer is formed on one surface of the first heat insulation layer, which is far away from the first electromagnetic wave absorption layer.

In addition, it should be noted that the method for manufacturing the electromagnetic shielding film provided in this embodiment is only one example for manufacturing the electromagnetic shielding film described in the first embodiment, and the electromagnetic shielding film described in the first embodiment may also be manufactured by other manufacturing methods. In addition, the preparation method of the electromagnetic shielding film according to the second to eighth embodiments may specifically refer to the preparation method of the electromagnetic shielding film provided in this embodiment, and will not be further described herein.

To sum up, the utility model provides an electromagnetic shielding film and circuit board, electromagnetic shielding film includes shielding layer 1, first electromagnetic wave absorbed layer 2, first insulating layer 3 and rete 4, first electromagnetic wave absorbed layer 2 is located shielding layer 1 with between the first insulating layer 3, rete 4 is located first insulating layer 3 is kept away from the one side of first electromagnetic wave absorbed layer 2. The first electromagnetic wave absorption layer 2 is arranged in the electromagnetic shielding film, so that the electromagnetic shielding film has the function of absorbing electromagnetic waves, and when the electromagnetic shielding film is applied to a circuit board, the electromagnetic shielding film can effectively absorb the electromagnetic waves generated by the circuit board, so that the electromagnetic interference is effectively shielded, the problem of larger electromagnetic interference of the circuit board in signal transmission is avoided, and the normal work of the circuit board is ensured; meanwhile, the first heat insulation layer 3 is arranged between the first electromagnetic wave absorption layer 2 and the adhesive film layer 4 to absorb or isolate heat generated when the first electromagnetic wave absorption layer 2 absorbs electromagnetic waves and heat generated by external devices, so that the problem that the electromagnetic shielding film is overheated and cracks due to the heat generated by the electromagnetic shielding film or the heat generated by the external devices is effectively avoided, and the electromagnetic shielding film is ensured to have good electromagnetic shielding efficiency.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, a plurality of modifications and replacements can be made without departing from the technical principle of the present invention, and these modifications and replacements should also be regarded as the protection scope of the present invention.

Claims

1. The electromagnetic shielding film is characterized by comprising a shielding layer, a first electromagnetic wave absorption layer, a first heat insulation layer and a glue film layer, wherein the first electromagnetic wave absorption layer is arranged between the shielding layer and the first heat insulation layer, and the glue film layer is arranged on one surface, far away from the first electromagnetic wave absorption layer, of the first heat insulation layer.

2. The electromagnetic shielding film of claim 1, further comprising a second thermal insulation layer disposed between the shielding layer and the first electromagnetic wave absorption layer.

3. The electro-magnetic shielding film of claim 1, further comprising a second electro-magnetic wave absorption layer disposed on a side of the shielding layer away from the first electro-magnetic wave absorption layer.

4. The electromagnetic shielding film of claim 3, further comprising a third thermal insulation layer disposed on a side of the second electromagnetic wave absorption layer away from the shielding layer.

5. The electro-magnetic shielding film of claim 3, further comprising a fourth thermal insulation layer disposed between the shielding layer and the second electro-magnetic wave absorption layer.

6. The electro-magnetic shielding film of claim 1, wherein a surface of the shielding layer adjacent to the first electro-magnetic wave absorption layer is provided with a conductive bump, and the conductive bump is embedded in the first electro-magnetic wave absorption layer.

7. The electro-magnetic shielding film according to claim 1, wherein a conductive bump is disposed on a surface of the shielding layer adjacent to the first electromagnetic wave absorption layer, the conductive bump includes a plurality of bumps, and the first electromagnetic wave absorption layer is disposed on a first region of the shielding layer and/or a second region of the conductive bump; the first region is a region where the conductive bump is not disposed in one surface of the shielding layer close to the first electromagnetic wave absorption layer, and the second region is a region formed between any two adjacent bumps in the conductive bump.

8. The electro-magnetic shielding film of claim 6 or 7, wherein the conductive protrusions are provided at their surfaces with conductive particles.

9. The electromagnetic shielding film according to any one of claims 1 to 7, wherein the first electromagnetic wave absorption layer has electrical conductivity, and the electrical conductivity of the first electromagnetic wave absorption layer is smaller than the electrical conductivity of the shielding layer; or the like, or, alternatively,

the first electromagnetic wave absorption layer has no conductivity.

10. The electromagnetic shielding film according to claim 3, wherein the second electromagnetic wave absorption layer has conductivity, and the conductivity of the second electromagnetic wave absorption layer is smaller than the conductivity of the shielding layer; or the like, or, alternatively,

the second electromagnetic wave absorption layer has no conductivity.

11. The electro-magnetic shielding film of claim 3, wherein at least one of the first electro-magnetic wave absorption layer and the second electro-magnetic wave absorption layer is composed of an adhesive and a wave-absorbing medium.

12. The electromagnetic shielding film according to claim 11, wherein the wave-absorbing medium is made of any one of a carbon-based wave-absorbing material, an iron-based wave-absorbing material, a ceramic-based wave-absorbing material, and a composite wave-absorbing material.

13. The electro-magnetic shielding film of claim 3, wherein the first electro-magnetic wave absorption layer has a thickness of: 0.1-45 μm; the thickness of the second electromagnetic wave absorption layer is as follows: 0.1-45 μm.

14. The electromagnetic shielding film according to any one of claims 1 to 7, wherein the adhesive layer comprises an adhesive layer containing conductive particles; or the like, or, alternatively,

15. The electro-magnetic shielding film of claim 1 or 2, further comprising an insulating layer disposed on a side of the shielding layer away from the first electro-magnetic wave absorption layer.

16. The electro-magnetic shielding film of claim 3 or 5, further comprising an insulating layer disposed on a side of the second electro-magnetic wave absorption layer away from the shielding layer.

17. A wiring board comprising a wiring board body and the electromagnetic shielding film according to any one of claims 1 to 16, provided on the wiring board body.