CN216600683U - Electromagnetic shielding film and printed circuit board with shielding structure - Google Patents
Electromagnetic shielding film and printed circuit board with shielding structure Download PDFInfo
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- CN216600683U CN216600683U CN202123457348.8U CN202123457348U CN216600683U CN 216600683 U CN216600683 U CN 216600683U CN 202123457348 U CN202123457348 U CN 202123457348U CN 216600683 U CN216600683 U CN 216600683U
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Abstract
The utility model discloses an electromagnetic shield membrane and take shielding structure's printed circuit board belongs to electromagnetic shield technical field, and it is relatively poor to have solved current shielding layer pliability, has defect such as hole, impurity, thickness inequality and shielding layer reflection electromagnetic wave to cause the problem of secondary interference. The electromagnetic shielding film comprises an insulating layer, a wave absorbing layer, a shielding layer and an adhesive layer which are sequentially stacked; the wave-absorbing layer is of a discontinuous structure, and one surface of the insulating layer facing the wave-absorbing layer comprises an uneven structure. The utility model discloses an electromagnetic shielding film can be able to bear or endure 180 fifty percent discount, and shielding effectiveness is about 80% of shielding effectiveness before the fifty percent discount after the fifty percent discount.
Description
Technical Field
The utility model belongs to the technical field of the electromagnetic shield, especially, relate to an electromagnetic shielding film and take shielding structure's printed circuit board.
Background
The flexible circuit board is a product which is printed on a flexible base material to design and manufacture a circuit pattern, and can be widely applied to industries such as mobile phones, liquid crystal display, communication, aerospace and the like. Electromagnetic Shielding (EMI Shielding) is an important indicator of flexible circuit boards.
At present, the structures of electromagnetic shielding films for flexible circuit boards mainly include the following three types: the first electromagnetic shielding film comprises an insulating layer and an omnibearing conductive adhesive layer formed on the surface of the insulating layer; the second electromagnetic shielding film comprises an insulating layer, and a shielding layer and a conductive adhesive layer which are sequentially formed on the surface of the insulating layer; the third electromagnetic film comprises an insulating layer, a shielding layer and an adhesive layer, wherein the shielding layer and the adhesive layer are sequentially formed on the surface of the insulating layer.
The electromagnetic shielding layer has the following problems:
on one hand, the shielding layer is required to be rough in surface, the shielding layer is mostly formed by thickening electroplating or near-scorching electroplating in the prior art, and the single surface of the shielding layer is roughened in an etching and roughening mode, so that the shielding layer prepared by the method is poor in flexibility, easy to fall powder and embrittle in the electroplating process, easy to cause defects of holes, impurities, uneven thickness and the like in etching, and has the phenomenon of electromagnetic wave penetration; on the other hand, the shielding layer may reflect external electromagnetic waves, so that other external areas are interfered by the electromagnetic waves.
SUMMERY OF THE UTILITY MODEL
In view of the above analysis, the utility model aims at providing an electromagnetic shielding film and take shielding structure's printed wiring board has solved among the prior art that the shielding layer pliability is relatively poor, has defect such as hole, impurity, thickness inequality and shielding layer reflection electromagnetic wave to cause the problem of secondary interference.
The purpose of the utility model is mainly realized through the following technical scheme:
on one hand, the utility model provides an electromagnetic shielding film, which comprises an insulating layer, a wave absorbing layer, a shielding layer and an adhesive layer which are sequentially stacked; the wave-absorbing layer is of a discontinuous structure, and one surface of the insulating layer facing the wave-absorbing layer comprises an uneven structure.
Furthermore, one surface of the shielding layer facing the wave absorbing layer and one surface of the shielding layer far away from the wave absorbing layer both comprise rugged structures.
Furthermore, more than 50% of the surface of the insulating layer facing the wave-absorbing layer comprises an uneven structure.
Furthermore, in one surface of the shielding layer facing the wave absorbing layer, more than 50% of the surface comprises an uneven structure; and/or more than 50% of one surface of the shielding layer far away from the wave absorbing layer comprises an uneven structure.
Furthermore, the Sku value of the insulating layer is 1.0-2.5, the Sp value is 1-9 μm, and the Sa value is 1-9 μm; and/or the Sku value of the shielding layer is 1.5-6.5, the Sp value is 0.1-9 μm, and the Sa value is 0.1-9 μm.
Further, the surface square resistance of the wave absorbing layer is controlled to be 5-50 omega-□。
Furthermore, the surface square resistance of the shielding layer is controlled to be 1-300 m omega-□。
Furthermore, a carrier layer is further arranged on one side, away from the wave-absorbing layer, of the insulating layer.
Furthermore, the electromagnetic shielding film also comprises a protective layer which is laminated on one surface of the adhesive layer far away from the shielding layer.
On the other hand, the utility model also provides a take shielding structure's printed wiring board, take shielding structure's printed wiring board includes above-mentioned electromagnetic shielding film.
Compared with the prior art, the utility model discloses can realize one of following beneficial effect at least:
a) the utility model provides an electromagnetic shielding film, the one side of insulating layer orientation absorbing layer is unevenness, absorbing layer is discontinuous structure, therefore prepare unevenness's insulating layer earlier during preparation, the discontinuous absorbing layer of refabrication, during the refabrication shielding layer, the shielding layer is close to the one side towards absorbing layer and keeps away from absorbing layer one side all can form unevenness as an organic whole, the thickness of shielding layer is even like this, can avoid the prior art need adopt alligatoring, the etching hole that arouses when improving the surface roughness of shielding layer, impurity, uneven scheduling problem of thickness; the shielding layer is of a galloping strip structure, is uniform in thickness, free of stress concentration points and good in flexibility. The utility model discloses ingenious rugged rough surface that utilizes the insulating layer forms discontinuous absorbing layer, finally obtains the rugged rough surface of metal shielding layer. The roughness of the single shielding layer in the prior art is avoided, the strength reduction and the flexibility reduction of the product are avoided. The utility model discloses an electromagnetic shielding film can be able to bear or endure 180 fifty percent discount, and shielding effectiveness is about 80% of shielding effectiveness before the fifty percent discount after the fifty percent discount.
b) In addition, the electromagnetic shielding film provided by the utility model is additionally provided with the wave-absorbing layer between the insulating layer and the shielding layer, on one hand, the wave-absorbing layer is in close contact with the shielding layer, and the wave-absorbing layer absorbs external electromagnetic waves and weakens the electromagnetic waves; or the electromagnetic wave is reflected by the shielding layer and is secondarily absorbed by the wave absorbing layer, so that the electromagnetic wave is weakened again, and the secondary interference of the electromagnetic wave is reduced or even eliminated.
c) The utility model provides a take shielding structure's printed circuit board satisfies the high-speed high frequency's of electronic product demand.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and drawings.
Drawings
The drawings are only for purposes of illustrating particular embodiments and are not to be construed as limiting the invention, wherein like reference numerals are used to designate like parts throughout the drawings.
Fig. 1 is one of the overall structural schematic diagrams of the electromagnetic shielding film of the present invention;
fig. 2 is a second schematic view of the overall structure of the electromagnetic shielding film of the present invention;
fig. 3 is a schematic diagram of the overall structure of the printed circuit board with the shielding structure according to the present invention.
Reference numerals:
1-a carrier layer; 2-an insulating layer; 3-a wave-absorbing layer; 4-a shielding layer; 5-an adhesive layer; 6-a protective layer; 7-printed wiring board, 8-ground plane.
Detailed Description
The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form a part hereof, and which together with the embodiments of the invention serve to explain the principles of the invention.
The utility model provides an electromagnetic shielding film, see figure 1, including carrier layer 1, insulating layer 2, absorbing layer 3, shielding layer 4 and the gluing layer 5 that stacks gradually, wherein, absorbing layer 3 is discontinuous structure, and insulating layer 2 contains unevenness's structure towards absorbing layer 3's a surface, and shielding layer 4 all contains unevenness's structure towards absorbing layer 3's a surface and keeping away from absorbing layer 3's a surface.
It should be noted that, among the prior art, the one side that the shielding layer is close to the insulating layer is the plane, and the one side that the insulating layer was kept away from to the shielding layer is the cockscomb structure, and the structure on the sawtooth is loose structure, and current process conditions is the alligatoring, modes such as etching, and the alligatoring produces the electroplating of nearly burnt modes such as column crystallization, and the etching is the corruption of liquid medicine, and cleaning process, stoving improper can cause the shielding layer hole to can cause the thickness of shielding layer inhomogeneous, and the pliability is relatively poor, shielding effect relatively poor grade defect.
Compared with the prior art, the utility model provides an electromagnetic shielding film, the one side of insulating layer orientation absorbing layer is unevenness, absorbing layer is discontinuous structure, consequently prepare unevenness's insulating layer earlier during the preparation, the absorbing layer of refabrication discontinuous structure, when the shield layer is refabricated, the shield layer is close to the one side towards absorbing layer and the one side of keeping away from absorbing layer can all form unevenness as an organic whole, the thickness of shield layer is even like this, can avoid prior art need adopt the coarsing like this, the hole that causes when the surface roughness of etch improvement shield layer, impurity, the uneven scheduling problem of thickness; the shielding layer is of a galloping strip structure, is uniform in thickness, free of stress concentration points and good in flexibility. The utility model discloses ingenious rugged rough surface that utilizes the insulating layer forms discontinuous structure's absorbing layer, finally obtains the rugged rough surface of metal shielding layer. The roughness of the single shielding layer is avoided, the strength reduction and the flexibility reduction of the product are avoided.
In addition, the electromagnetic shielding film provided by the utility model is additionally provided with the wave-absorbing layer between the insulating layer and the shielding layer, on one hand, the wave-absorbing layer is in close contact with the shielding layer, and the wave-absorbing layer absorbs external electromagnetic waves and weakens the electromagnetic waves; or the electromagnetic wave is reflected by the shielding layer and is secondarily absorbed by the wave absorbing layer, so that the electromagnetic wave is weakened again, and the secondary interference of the electromagnetic wave is reduced or even eliminated.
Specifically, more than 50% of the surface of the insulating layer 2 facing the wave-absorbing layer 3 comprises an uneven structure.
Specifically, more than 50% of the surface of the shielding layer 4 facing the wave-absorbing layer 3 comprises an uneven structure.
Specifically, in one surface of the shielding layer 4 far away from the wave-absorbing layer 3, more than 50% of the surface comprises an uneven structure.
Considering that the wave-absorbing layer 3 mainly plays a role in reducing or even eliminating electromagnetic waves, in order to ensure the function of the wave-absorbing layer 3, illustratively, the thickness of the wave-absorbing layer 3 is 0.001-1.0 μm, and for the material of the wave-absorbing layer 3, the wave-absorbing layer 3 may be made of at least one of iron, cobalt, nickel, iron-silicon alloy, iron-nickel alloy, iron-silicon-aluminum, and iron-silicon-chromium.
Specifically, the surface square resistance of the wave absorbing layer 3 is controlled to be 5-50 omega-□。
Also, considering that the shielding layer 4 mainly functions as an electric shield, in order to secure an electric shield type of the shielding layer 4, illustratively, the thickness of the above-mentioned shielding layer 4 is 0.05 to 4.5 μm, and as a material of the shielding layer 4, specifically, the shielding layer 4 may be made of one or two or more elements of gold, silver, copper, and aluminum.
Considering that the conductivity of the soft magnetic metal or alloy in the wave-absorbing layer 3 is not as good as that of the metal in the shielding layer 4, the discontinuous soft magnetic metal or alloy particles in the wave-absorbing layer 3 have magnetic resistance and resistance, no eddy current loss is generated in the wave-absorbing layer 3, and the absorption of electromagnetic waves is facilitated. Thus, the wave-absorbing layer is a discontinuous wave-absorbing layer.
Specifically, the side of the insulating layer 2 far away from the wave-absorbing layer 3 is further provided with a carrier layer 1, and the carrier layer 1 is selected to be a smooth film or a matte film. That is, both the upper surface and the lower surface of the carrier layer 1 may be matte films, or both the upper surface and the lower surface of the carrier layer 1 may be smooth films (as shown in fig. 2), or one surface of the carrier layer 1 may be a smooth film and one surface may be a matte film (as shown in fig. 1).
Illustratively, the thickness of the carrier layer 1 is 40-60 μm.
Specifically, the insulating layer 2 may be a black film layer, a white film layer, or a brown film layer.
Specifically, the insulating layer may be one of a PPS film, a PE film, a polyester film, a polyimide film, a film layer formed after curing an epoxy resin ink, a film layer formed after curing a polyurethane ink, a film layer formed after curing a modified acrylic resin, and a film layer formed after curing a polyimide resin.
In view of the black film layer having a characteristic of shielding light and hiding an internal structure, it is preferable that the insulating layer 2 is a black film layer.
Illustratively, too large a thickness of the insulating layer 2 does not satisfy the demand for a thin electronic component, and too small an insulating property is not good. Therefore, the thickness of the insulating layer 2 is controlled to be 3 to 10 μm.
It can be understood that, in order to effectively protect shielding layer 4, above-mentioned electromagnetic shielding film still includes range upon range of in gluing layer 5 one side protective layer 6 (for example, from the type protective layer) far away from shielding layer 4, and like this, protective layer 6 closely laminates with shielding layer 4 through gluing layer 5, and protective layer 6 can effectively protect shielding layer 4, avoids causing damage to it and influences electromagnetic shield effect.
Specifically, the thickness of the adhesive layer 5 is 3 to 15 μm, and the thickness of the adhesive layer 5 is more preferably 5 to 10 μm.
Specifically, the thickness of the protective layer 6 is 70 to 80 μm.
Illustratively, the roughness of the carrier layer 1, the insulating layer 2, the wave-absorbing layer 3 and the shielding layer 4 may be set as shown in table 1 below.
TABLE 1 roughness parameters of layers of electromagnetic shielding films
| Sku | Sp(μm) | Sa(μm) | |
| The carrier layer faces away from the insulating layer | 0～3.0 | 0～25 | 0～25 |
| The carrier layer faces the insulating layer | 0～1.5 | 0～6 | 0～6 |
| Insulating layer facing wave-absorbing layer | 1.0～2.5 | 1～9 | 1～9 |
| Wave absorbing layer | 1.0～2.5 | 1～9 | 1～9 |
| Shielding layer | 1.5～6.5 | 0.1～9 | 0.1～9 |
In table 1, Sku refers to kurtosis (sharpness), Sp refers to maximum peak height, and Sa refers to arithmetic mean height of the surface.
As shown in table 1 above, the adhesive layer 5 is too thick in consideration of the Sku, Sp, Sa values of the shield layer 4 being too large; and if the size is too small, the contact resistance of the circuit board is increased by pressing the shielding layer 4. Therefore, the Sku value of the control shield layer 4 is 1.5 to 6.5, the Sp value is 0.1 to 9 μm, and the Sa value is 0.1 to 9 μm.
Specifically, the surface sheet resistance of the shielding layer 4 is controlled to be 1-300 m Ω -□。
Considering that the Sku value of the insulating layer 2 is too large, the tight connection of the wave-absorbing layer 3 and the shielding layer 4 is influenced; too small, affects the roughness of the other sides of the wave-absorbing layer 3 and the shielding layer 4. Therefore, the Sku value of the control insulating layer 2 is 1.0 to 2.5.
Considering that the Sp and Sa values of the insulating layer 2 are too large, the tight connection of the shielding layer 4 is influenced; too small, affects the roughness of the other side of the shield layer 4. Therefore, the Sp value of the control insulating layer 2 is 1 to 9 μm, and the Sa value is 1 to 9 μm.
Considering that the Sku, Sp and Sa values of the wave-absorbing layer 3 are too large to influence the tight connection of the shielding layer 4; too small, affects the roughness of the other side of the shield. Therefore, the Sku value of the wave-absorbing layer 3 is controlled to be 1.0-2.5, the Sp value is controlled to be 1-9 μm, and the Sa value is controlled to be 1-9 μm.
Specifically, the adhesive layer 5 may be made of at least one of a modified epoxy resin adhesive, an acrylic adhesive, a modified rubber adhesive, and a modified thermoplastic polyimide adhesive.
Specifically, consider that protective layer 6 needs to peel off easily, avoid silicon migration to lead to gluing layer 5 to bond out the problem simultaneously, protective layer 6 can adopt from the PET that the type power is 75 ~ 300g/inch from type membrane, PE from type membrane, OPP from type membrane, PC from type membrane, PS barrier film, PMMA from type membrane and BOPP from type one of the membrane.
The electromagnetic shielding film of the utility model can be prepared by adopting the following preparation method:
step 1, providing a carrier layer 1;
step 2, sequentially forming an insulating layer 2 with a surface comprising a rugged structure, a wave-absorbing layer 3 with a discontinuous structure and a shielding layer 4 with the rugged structure on one surface of a carrier layer 1;
step 3, forming an adhesive layer 5 on the surface of the shielding layer 4 in a coating mode;
and 4, adhering a protective layer 6 to the surface of the adhesive layer 5.
Specifically, the above-described formation of the insulating layer 2 having a rugged structure on the surface may include various methods, for example: reverse coating or sequential coating of an anilox roller is adopted, and a wave crest and trough rudiment is created through holes of the anilox roller;
or a 3D printer is adopted to form an uneven structure;
or screen printing paste which is not leveled is adopted to form the screen printing, and the uneven insulating layer 2 is formed;
or other prior art techniques may be used to form the insulating layer 2 comprising a rugged structure.
Specifically, the wave-absorbing layer 3 forming the discontinuous structure includes various methods, for example:
adopting a vapor deposition method, and adopting interfering atoms, such as the same cavity, and soft magnetic atoms or molecules in the vertical direction of a copper atom horizontal direction interfering part to form a discontinuous wave absorbing layer 3 in the deposition process;
or a vapor deposition method is adopted, and a reticular structure is added in the deposition process, so that shielding can be realized, and a discontinuous wave absorbing layer 3 is formed;
or other prior art is adopted to form the wave-absorbing layer 3 with a discontinuous structure.
Specifically, the forming of the shielding layer 4 including the rugged structure includes the steps of:
s1, forming a shielding layer with a rugged structure on the surface by adopting a sputtering mode on the wave absorbing layer 3 or the insulating layer 2;
s2, adopt the electroplating mode to thicken on unevenness ' S surface on foretell shielding layer, form and keep away from shielding layer 4 that the one side of absorbing the wave layer contains unevenness ' S structure, shielding layer 4 ' S surperficial side is hindered at 1 ~ 300m omega-□。
Specifically, the manner of forming the shielding layer 4 may include: PVD, CVD, evaporation plating, sputter plating, electroless plating, electroplating, or a combination thereof.
The utility model also provides a take shielding structure's printed wiring board, including the electromagnetic shielding film that the aforesaid provided.
Specifically, as shown in fig. 3, the printed wiring board with the shielding structure includes a printed wiring board 7 and the electromagnetic shielding film with the carrier layer 1 and the protective layer 6 removed; the printed wiring board 7 and the adhesive layer 5 of the electromagnetic shielding film are combined into one body in the thickness direction.
Specifically, the printed wiring board 7 is provided with a ground layer 8; the shield layer 4 is electrically connected to the ground layer 8. The printed circuit board with the shielding structure comprises an insulating layer 2, a wave absorbing layer 3, a shielding layer 4, an adhesive layer 5, a grounding layer and a printed circuit board 7 which are sequentially stacked; the shield layer 4 is electrically connected to the ground layer 8.
Specifically, the printed wiring board may be one of a flexible single-sided board, a double-sided board, a multilayer board, and a rigid-flex printed board.
Compared with the prior art, the utility model provides a take shielding structure's printed circuit board satisfies the high-speed high frequency's of electronic product demand.
Examples 1 to 1
The embodiment provides an electromagnetic shielding film, which comprises a carrier layer 1, an insulating layer 2, a wave absorbing layer 3, a shielding layer 4, an adhesive layer 5 and a protective layer 6 which are sequentially compounded from top to bottom; the wave-absorbing layer 3 is of a discontinuous structure, more than 90% of the surface of the insulating layer 2 facing the wave-absorbing layer 3 comprises an uneven structure, and more than 90% of the surface of the shielding layer 4 facing the wave-absorbing layer 3 comprises an uneven structure; in one surface of the shielding layer 4 far away from the wave-absorbing layer 3, more than 90% of the surface comprises an uneven structure.
The carrier layer 1 is a matte film, and the thickness of the carrier layer 1 is 50 μm;
the thickness of the insulating layer 2 is 5 μm; the insulating layer 2 adopts a black film;
the thickness of the wave-absorbing layer 3 is 0.01 μm; the surface square resistance of the wave absorbing layer 3 is 20-30 omega□；
The thickness of the shielding layer 4 is 0.2 μm; the surface square resistance of the shielding layer 4 is 20-30 m omega□；
The thickness of the adhesive layer 5 is 7 μm;
the thickness of the protective layer 6 was 75 μm.
The surface roughness parameter table of the above electromagnetic shielding film is shown in the following table 2:
TABLE 2 surface roughness parameters of electromagnetic shielding films
| Sku | Sp(μm) | Sa(μm) | |
| The carrier layer faces away from the insulating layer | 3.0 | 20 | 25 |
| The carrier layer faces the insulating layer | 1.5 | 5 | 6 |
| Insulating layer facing wave-absorbing layer | 2.5 | 8 | 9 |
| Wave absorbing layer | 2.5 | 8 | 9 |
| Shielding layer | 6.5 | 8 | 9 |
The performance parameters of the electromagnetic shielding film of the present embodiment are shown in table 3 below, and it can be seen that the electromagnetic shielding film of the present embodiment resists 180 ° double folding, and the shielding effectiveness after double folding is about 80% of the shielding effectiveness before double folding.
TABLE 3 Performance parameters of the electro-magnetic shielding film of example 1-1
Examples 1 to 2
This embodiment provides a printed wiring board with a shield structure, comprising the electromagnetic shield film provided in embodiment 1-1 above with the carrier layer 1 and the protective layer 6 removed. The printed circuit board with the shielding structure comprises an insulating layer 2, a wave absorbing layer 3, a shielding layer 4, an adhesive layer 5, a grounding layer and a printed circuit board 7 which are sequentially stacked; the shield layer 4 is electrically connected to the ground layer 8.
Specifically, the printed wiring board 7 and the adhesive layer 5 of the electromagnetic shielding film are combined into one in the thickness direction.
The printed wiring board with a shielding structure of the present embodiment satisfies the demand for high-speed and high-frequency electronic products.
Example 2
The embodiment provides an electromagnetic shielding film, which comprises a carrier layer 1, an insulating layer 2, a wave-absorbing layer 3, a shielding layer 4, an adhesive layer 5 and a protective layer 6 which are sequentially compounded from top to bottom; the wave-absorbing layer 3 is of a discontinuous structure, more than 50% of the surface of the insulating layer 2 facing the wave-absorbing layer 3 comprises an uneven structure, and more than 50% of the surface of the shielding layer 4 facing the wave-absorbing layer 3 comprises an uneven structure; in one surface of the shielding layer 4 far away from the wave-absorbing layer 3, more than 50% of the surface comprises an uneven structure.
The support layer 1 is a smooth film, and the thickness of the support layer 1 is 40 μm;
the thickness of the insulating layer 2 is 3 μm; the insulating layer 2 adopts a white film layer;
the thickness of the wave-absorbing layer 3 is 0.005 mu m; the surface square resistance of the wave absorbing layer 3 is 30-50 omega□；
The thickness of the shielding layer 4 is 0.1 μm; the surface square resistance of the shielding layer 4 is 100-150 m omega□；
The thickness of the adhesive layer 5 is 3 μm;
the thickness of the protective layer 6 was 70 μm.
The surface roughness parameter table of the above electromagnetic shielding film is shown in the following table 4:
table 4 surface roughness parameters of the electro-magnetic shielding film of example 2
The performance parameters of the electro-magnetic shielding film obtained in this example are shown in table 5 below.
TABLE 5 Properties of the electro-magnetic shielding film of example 2
Example 3
The embodiment provides an electromagnetic shielding film, which comprises a carrier layer 1, an insulating layer 2, a wave-absorbing layer 3, a shielding layer 4, an adhesive layer 5 and a protective layer 6 which are sequentially compounded from top to bottom; the wave-absorbing layer 3 is of a discontinuous structure, more than 80% of the surface of the insulating layer 2 facing the wave-absorbing layer 3 comprises an uneven structure, and more than 80% of the surface of the shielding layer 4 facing the wave-absorbing layer 3 comprises an uneven structure; in one surface of the shielding layer 4 far away from the wave-absorbing layer 3, more than 80% of the surface comprises an uneven structure.
The carrier layer 1 is a matte film, and the thickness of the carrier layer 1 is 60 mu m;
the thickness of the insulating layer 2 is 9 μm; the insulating layer 2 adopts a brown film layer;
the thickness of the wave-absorbing layer 3 is 0.8 μm; the surface square resistance of the wave absorbing layer 3 is 10-20 omega□；
The thickness of the shielding layer 4 is 4.0 μm; the surface square resistance of the shielding layer 4 is 10-20 m omega□；
The thickness of the adhesive layer 5 is 12 μm;
the thickness of the protective layer 6 was 80 μm.
The surface roughness parameter table of the above electro-magnetic shielding film is shown in the following table 6:
TABLE 6 surface roughness parameters of electromagnetic shielding films
| Sku | Sp(μm) | Sa(μm) | |
| The carrier layer faces away from the insulating layer | 2.0 | 10 | 15 |
| The carrier layer faces the insulating layer | 0.0 | 0 | 0 |
| Insulating layer facing wave-absorbing layer | 1.0 | 5 | 6 |
| Wave absorbing layer | 1.0 | 5 | 6 |
| Shielding layer | 1.5 | 5 | 6 |
The performance parameters of the electro-magnetic shielding film obtained in this example are shown in table 7 below.
TABLE 7 Properties of the electro-magnetic shielding film of example 3
The printed wiring board with a shielding structure including the electromagnetic shielding films of embodiments 2 and 3 satisfies the demand for high-speed and high-frequency electronic products.
Comparative example 1
The present comparative example provides a printed wiring board with a shielding structure, including an electromagnetic shielding film. The electromagnetic shielding film comprises a carrier film, an insulating layer, an electromagnetic shielding layer, an adhesive layer and a release film.
Forming an insulating layer on the carrier film: selecting a PET release film with the width of 1090mm and the thickness of 50 micrometers, coating ink on one side of a release surface of the PET release film, and forming an insulating layer after complete curing, wherein the ink is epoxy resin ink or polyurethane ink and is 3-10 micrometers in thickness;
forming a shielding layer on the insulating layer in a chemical plating mode, wherein the shielding layer is made of copper;
roughening the surface of the electromagnetic shielding layer: the method of roughening the copper foil of the circuit board is adopted, one surface of the electromagnetic shielding layer is roughened firstly, then solidified and passivated;
coating one of the following substances on the electromagnetic shielding layer: drying the modified epoxy resin, the modified acrylic resin, the modified rubber and the modified thermoplastic polyimide to volatilize the solvent, and forming an adhesive layer; wherein after roughening, the thickness of the electromagnetic shielding layer is 0.1-6 μm, and the roughness is 0.3-5 μm; the thickness of the insulating layer is 1 to 25 μm, and the thickness of the adhesive layer is 1 to 8 μm.
The performance parameters of the electro-magnetic shielding film obtained in the present comparative example are shown in table 8 below.
TABLE 8 Performance parameters of the electro-magnetic shielding film of comparative example 1
It can be seen from comparing examples 1-1, 2, 3 and 1 that the electromagnetic shielding film of the present invention has good flexibility and shielding effectiveness. For example, the electromagnetic shielding film of the utility model can resist 180 degrees of folding, and the shielding effectiveness after the folding is about 80 percent of the shielding effectiveness before the folding.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention should be covered by the present invention.
Claims (10)
1. The electromagnetic shielding film is characterized by comprising an insulating layer (2), a wave absorbing layer (3), a shielding layer (4) and an adhesive layer (5) which are sequentially laminated; the wave-absorbing layer (3) is of a discontinuous structure, and one surface of the insulating layer (2) facing the wave-absorbing layer (3) comprises an uneven structure.
2. Electromagnetic shielding film according to claim 1, characterized in that one surface of the shielding layer (4) facing towards the wave-absorbing layer (3) and one surface facing away from the wave-absorbing layer (3) comprise an uneven structure.
3. Electromagnetic shielding film according to claim 1, characterized in that more than 50% of the surface of the insulating layer (2) facing the wave-absorbing layer (3) comprises an uneven structure.
4. The electromagnetic shielding film according to claim 2, wherein more than 50% of the surface of the shielding layer (4) facing the wave-absorbing layer (3) comprises an uneven structure; and/or more than 50% of one surface of the shielding layer (4) far away from the wave absorbing layer (3) comprises an uneven structure.
5. The electromagnetic shielding film according to claim 1, wherein the insulating layer (2) has a Sku value of 1.0 to 2.5, an Sp value of 1 to 9 μm, and a Sa value of 1 to 9 μm; and/or the presence of a gas in the gas,
the Sku value of the shielding layer (4) is 1.5-6.5, the Sp value is 0.1-9 μm, and the Sa value is 0.1-9 μm.
6. The electromagnetic shielding film according to claim 1, wherein the surface sheet resistance of the wave-absorbing layer (3) is controlled to be 5-50 Ω/□.
7. The EMI shielding film as claimed in claim 1, wherein the surface sheet resistance of said shielding layer (4) is controlled to be 1-300 m Ω/□.
8. Electromagnetic shielding film according to claim 1, characterized in that a carrier layer (1) is further provided on the side of the insulating layer (2) remote from the wave-absorbing layer (3).
9. The electromagnetic shielding film according to claim 1, further comprising a protective layer (6) laminated on a side of the adhesive layer (5) remote from the shielding layer (4).
10. A printed wiring board with a shielding structure, characterized in that it comprises the electromagnetic shielding film of claim 1.
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| CN202123457348.8U CN216600683U (en) | 2021-12-31 | 2021-12-31 | Electromagnetic shielding film and printed circuit board with shielding structure |
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| CN202123457348.8U CN216600683U (en) | 2021-12-31 | 2021-12-31 | Electromagnetic shielding film and printed circuit board with shielding structure |
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