Shielding film and manufacturing method thereof
Technical Field
The invention relates to the technical field of electromagnetic shielding, in particular to a shielding film and a manufacturing method thereof.
Background
With the development of technology, radio frequency devices are widely used. Common radio frequency equipment such as industrial electrical equipment, broadcast television transmitting towers, wireless communication networks, high-voltage transmission lines, household appliances and the like can transmit electromagnetic wave energy outwards during working to generate electromagnetic radiation, the electromagnetic radiation can affect human bodies or machines, the degree of the electromagnetic radiation is directly related to the energy of the electromagnetic radiation, the energy generated by the electromagnetic radiation depends on the frequency of the electromagnetic radiation, the electromagnetic radiation can be arranged into a plurality of levels from low to high according to the frequency, the higher the frequency is, the larger the energy generated by the electromagnetic radiation is, and the overlarge electromagnetic radiation energy can damage physiological tissue molecules of the human bodies. Nowadays, radio frequency devices are equipped in a large number in places where people are moving, the frequency spectrum range is continuously widened, the intensity is multiplied, if electromagnetic radiation exceeds the limit which can be born by human bodies or machines, electromagnetic pollution is formed, the electromagnetic pollution not only can interfere electronic devices, but also can threaten human health, and is a 'stealth killer' with serious harm, and the electromagnetic pollution becomes the fifth pollution following atmospheric pollution, water pollution, solid waste pollution and noise pollution. The most effective solution to the problem of electromagnetic pollution is to use electromagnetic shielding technology, including absorption and reflection electromagnetic shielding, and to use electromagnetic shielding materials to shield the electromagnetic waves. Different application fields have different requirements on electromagnetic shielding materials. In the occasions needing visual observation, transparent electromagnetic shielding materials are needed, and the application fields comprise medical electromagnetic isolation room observation windows, communication equipment transparent electromagnetic shielding elements, aerospace equipment optical windows, advanced optical instrument optical windows, security facility electromagnetic leakage prevention optical windows, liquid crystal display screens, mobile phone touch screens, vehicle-mounted transparent antennas and the like. In the prior art, in order to realize transparent electromagnetic shielding, a transparent electromagnetic shielding film is generally used. The transparent shielding film can reflect electromagnetic radiation back to the space, causing secondary pollution to the space environment, and cannot thoroughly prevent and treat electromagnetic pollution. The transparent metal oxide film mainly made of indium tin oxide is widely applied to visible light transparent occasions, but the transparent wave band is narrow, although the microwave shielding wave band is wide, the shielding capability is weak, the material is hard, the flexibility is poor, and the surface bonding cannot be well carried out.
Disclosure of Invention
In view of the above, the present invention provides a shielding film, which includes a substrate layer, a wave-absorbing conductive layer and a protective layer, wherein a plurality of grooves are formed on one surface of the substrate layer, the grooves are filled with wave-absorbing conductive materials to form the wave-absorbing conductive layer, and the protective layer at least covers the wave-absorbing conductive layer, or at least covers the wave-absorbing conductive layer and one surface of the substrate layer having the grooves.
A shielding film proposed according to an object of the present invention includes:
the substrate layer comprises a first surface and a second surface which are opposite, and the first surface is provided with a plurality of grooves;
and the wave-absorbing conducting layer is formed by filling wave-absorbing conducting materials in the grooves to form communicated grids.
A barrier film, comprising:
the substrate layer comprises a first surface and a second surface which are opposite, and the first surface and the second surface are both provided with a plurality of grooves;
a first wave absorption conductive layer, wherein the grooves on the first surface are filled with wave absorption conductive materials to form communicated grids to form the first wave absorption conductive layer,
and the grooves on the second surface are filled with wave-absorbing conductive materials to form communicated grids to form the second wave-absorbing conductive layer.
Preferably, the grid is periodic, or aperiodic, or random.
Preferably, the height of the grooves ranges from 500nm to 10 μm, the width of the grooves ranges from 500nm to 10 μm, and the separation distance of the grooves ranges from 500nm to 500 μm.
Preferably, the cross section of the groove is square, rectangular or trapezoidal.
Preferably, the side of the mesh away from the second surface is planar, convex or concave.
Preferably, the height of the shielding layer is smaller than the depth of the groove, or equal to the depth of the groove, or larger than the depth of the groove.
Preferably, the shielding film comprises at least one protective layer, and the protective layer at least partially covers the wave-absorbing conductive layer.
Preferably, the first surface of the substrate layer is further provided with a polymer layer, and the polymer layer is a transparent thermosetting adhesive layer or a transparent light-curing adhesive layer.
Preferably, the substrate layer is made of transparent heat-curing adhesive, light-curing adhesive or flexible polymer materials such as PET (polyethylene terephthalate) and PC (polycarbonate), and the wave-absorbing conducting layer is made of metal or graphene or a material doped with titanium carbide in a carbon nano tube.
The invention also discloses a manufacturing method of the shielding film, which comprises the following steps:
(A) manufacturing a graphical grid groove on a substrate by a laser direct writing technology;
(B) placing the substrate in an electroforming tank, and manufacturing a metal template by an electroforming technology;
(C) directly imprinting a flexible substrate or coating a curing adhesive on the substrate by using a nano-imprinting technology with a metal template as a mother matrix, and forming a patterned grid groove after curing;
(D) and filling the wave-absorbing conductive slurry into the patterned grid grooves by adopting a blade coating technology to manufacture the shielding film.
Compared with the prior art, the shielding film disclosed by the invention has the advantages that: the shielding film is used for doping and filling the shielding material and the wave-absorbing material, so that a repeated filling process is simplified, the structure is simplified, the manufacturing process is relatively simple, mass production is facilitated, the transparent characteristic is maintained, the shielding capability is strong, the flexibility is good, the attachment is convenient, and the application range is wide; the shielding film reduces the reflection of electromagnetic radiation back to the space, and is beneficial to preventing and treating electromagnetic radiation pollution.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Fig. 1 is a schematic cross-sectional view of a first preferred embodiment of a shielding film of the present invention.
FIG. 2 is a schematic cross-sectional view of a first variation of a first preferred embodiment of a shielding film of the present invention.
FIG. 3 is a schematic cross-sectional view of a second variation of the first preferred embodiment of a shielding film of the present invention.
FIG. 4 is a schematic cross-sectional view of a third variation of the first preferred embodiment of the shielding film of the present invention.
FIG. 5 is a schematic cross-sectional view of a fourth variation of the first preferred embodiment of the shielding film of the present invention.
FIG. 6 is a schematic cross-sectional view of a second preferred embodiment of a shielding film of the present invention.
FIG. 7 is a schematic cross-sectional view of a shielding film according to a third preferred embodiment of the present invention.
FIG. 8 is a schematic cross-sectional view of a fourth preferred embodiment of a shielding film of the present invention.
Detailed Description
Referring to fig. 1, a shielding film according to a first preferred embodiment of the present invention includes a substrate layer 10, a waveguide absorbing layer 20, and a protective layer 30. The substrate layer 10 has a first surface 11 and a second surface 12 opposite to each other. The first surface 11 has a plurality of grooves 111, and the grooves 111 are uniformly distributed on the first surface 11. The grooves 111 form an interconnected network on the first surface 11, which network may be periodic or aperiodic. The cross-section of the groove 111 is rectangular in fig. 1, but it should be noted that the cross-section of the groove 111 can also be square, or the cross-section of the groove 111 can be trapezoidal as shown in the first variation of the first preferred embodiment in fig. 2.
It is worth noting that under the condition that the spacing distance of the grooves 111 is the same, when the width of the groove 111 is 500nm, the light transmittance of the shielding film is good, the shielding performance is poor, when the width is 10um, the light transmittance is poor, the shielding performance is good, and preferably, the width of the groove 111 is 5 μm, so as to realize the balance between the light transmittance and the shielding performance. When the widths of the grooves 111 are the same, the larger the interval of the grooves 111 is, the better the light transmittance is, and the worse the shielding performance is, the smaller the interval of the grooves 111 is, the worse the light transmittance is, and the better the shielding performance is, and the interval distance of the grooves 111 is set to be 500nm to 500 μm, preferably 250 μm.
The wave-absorbing conductive layer 20 is formed by a wave-absorbing conductive material filled in the groove 111, specifically, the wave-absorbing conductive layer 20 includes a plurality of wave-absorbing conductive strips 21, the wave-absorbing conductive strips 21 are the same as the groove 111 in number, the wave-absorbing conductive strips 21 are respectively disposed inside the groove 111, and the height of the wave-absorbing conductive strips 21 is smaller than the depth of the groove 111. As shown in fig. 1, the surface of the wave-absorbing conductive strip 21 away from the second surface 12 is a plane, but the surface is not limited to be a plane, and may be a convex surface or a concave surface. The protective layer 30 comprises a plurality of protective strips 31, the number of the protective strips 31 is the same as that of the wave-absorbing conductive strips 21, the protective strips 31 respectively cover the wave-absorbing conductive strips 21, and the protective strips 31 respectively protect the wave-absorbing conductive strips 21. The shielding film is not required to be prepared with a shielding layer and a wave-absorbing layer respectively in the preparation process, the preparation process is simplified, the production cost is reduced, the production efficiency is improved, and the large-scale batch production of the shielding film is facilitated.
Preferably, the substrate layer 10 is made of transparent heat-curable adhesive, light-curable adhesive or transparent flexible polymer materials such as PET and PC, and has good light transmittance and strong flexibility. The wave-absorbing conductive layer 20 is made of a conductive material and a wave-absorbing material, for example, a metal, graphene, or carbon nanotube is doped with titanium carbide.
As shown in fig. 3, a second variation of the first preferred embodiment of the shielding film is different from the first preferred embodiment in that a protective layer 30A covers the first surface 11, and a surface of the protective layer 30A contacting the substrate layer 10 has a plurality of protrusions 31A, the number of the protrusions 31A is the same as that of the grooves 111, and the protrusions 31A and the grooves 111 are respectively disposed correspondingly to fill the remaining space in the grooves 111, and the protrusions 31A are respectively connected to the wave-absorbing conductive strips 21 in a contacting manner.
As shown in fig. 4, a third variation of the first preferred embodiment of the shielding film is different from the first preferred embodiment in that the wave-absorbing conductive layer and the protective layer, a wave-absorbing conductive layer 20B in the variation includes a plurality of wave-absorbing conductive strips 21B, the number of the wave-absorbing conductive strips 21B is the same as that of the grooves 111, the wave-absorbing conductive strips 21B are respectively disposed inside the grooves 111, and the height of the wave-absorbing conductive strips 21B is equal to the depth of the grooves 111. The protective layer 30B is disposed on the first surface 11, and the protective layer 30B is connected to the substrate layer 10 and the wave-absorbing conductive layer 20B.
As shown in fig. 5, a fourth variant of the first preferred embodiment of the shielding film is different from the first preferred embodiment in that the wave-absorbing conductive layer and the protective layer, a wave-absorbing conductive layer 20C in this variant includes a plurality of wave-absorbing conductive strips 21C, the number of the wave-absorbing conductive strips 21C is the same as that of the grooves 111, the wave-absorbing conductive strips 21C are respectively disposed inside the grooves 111, the height of the wave-absorbing conductive strips 21C is greater than the depth of the grooves 111, and a portion of the wave-absorbing conductive strips 21C extending out of the grooves 111 is a protrusion 211C. The protective layer 30C covers the first surface 11, a plurality of recesses 301C are formed in one surface of the protective layer 30C, which is in contact with the substrate layer 10C, the number of the recesses 301C is the same as that of the protruding portions 211C, and the recesses 301C and the protruding portions 211C are respectively and correspondingly and tightly combined.
As shown in fig. 6, the second preferred embodiment of the shielding film is different from the first preferred embodiment in the base material layer. The substrate layer 10A in this embodiment includes a first substrate layer 101A and a first polymer layer 102A, the first substrate layer 101A and the first polymer layer 102A are tightly bonded to form a bonding surface, one side of the first polymer layer 102A away from the bonding surface is a first surface 11A, one side of the first substrate layer 101A away from the bonding surface is a second surface 12A, the first surface 11A has a plurality of first grooves 111A, and the wave-absorbing conductive layer 20 and the protective layer 30 are bonded to the first polymer layer 102A. It is noted that the second preferred embodiment can adopt the variations of the first preferred embodiment, resulting in variations of the second preferred embodiment.
As shown in fig. 7, a third preferred embodiment of the shielding film, which is a double-sided structure, includes a substrate layer 10D, a first wave-absorbing conductive layer 21D, and a second wave-absorbing conductive layer 22D. The substrate layer 10D has a first surface 11D and a second surface 12D opposite to each other. The first surface 11D has a plurality of first grooves 111D, and the first grooves 111D are uniformly distributed on the first surface 11D; the second surface 12D has a plurality of second grooves 121D thereon, and the second grooves 121D are uniformly distributed on the second surface 12D. The first waveguide absorption layer 21D is formed by a wave-absorbing conductive material filled in the first groove 111D, specifically, the first waveguide absorption layer 21D includes a plurality of first waveguide absorption strips 211D, the number of the first waveguide absorption strips 211D is the same as that of the first groove 111D, the first waveguide absorption strips 211D are respectively disposed inside the first groove 111D, and the height of the first waveguide absorption strips 211D is smaller than the depth of the first groove 111D. The shielding film further comprises a first protection layer 31D, the first protection layer 31D comprises a plurality of first protection strips 311D, the number of the first protection strips 311D is the same as that of the first waveguide absorption strips 211D, the first protection strips 311D respectively cover the first waveguide absorption strips 211D, and the first protection strips 311D respectively protect the first waveguide absorption strips 211D. The second wave-absorbing conductive layer 22D is formed by a wave-absorbing conductive material filled in the second groove 121D, specifically, the second wave-absorbing conductive layer 22D includes a plurality of second wave-absorbing conductive strips 221D, the second wave-absorbing conductive strips 221D are the same as the second groove 121D in number, the second wave-absorbing conductive strips 221D are respectively disposed inside the second groove 121D, and the height of the second wave-absorbing conductive strips 221D is smaller than the depth of the second groove 121D. The shielding film further comprises a second protective layer 32D, the second protective layer 32D comprises a plurality of second protective strips 321D, the second protective strips 321D are the same as the second wave-absorbing conductive strips 221D in number, the second protective strips 321D respectively cover the second wave-absorbing conductive strips 221D, and the second protective strips 321D respectively protect the second wave-absorbing conductive strips 221D.
Fig. 8 shows a fourth preferred embodiment of the shielding film, which is different from the third preferred embodiment in the base material layer. The substrate layer 10E in this embodiment includes a first substrate layer 101E and two first polymer layers 102E, the first substrate layer 101E and the two first polymer layers 102E are tightly bonded to form a bonding surface, and a first surface 11E and a second surface 12E are respectively on a side of the two first polymer layers 102E away from the bonding surface.
The invention also discloses a manufacturing method of the shielding film, which comprises the following steps:
(A) manufacturing a graphical grid groove on a substrate by a laser direct writing technology;
(B) placing the substrate in an electroforming tank, and manufacturing a metal template by an electroforming technology;
(C) directly imprinting a flexible substrate or coating a curing adhesive on the substrate by using a nano-imprinting technology with a metal template as a mother matrix, and forming a patterned grid groove after curing;
(D) and filling the wave-absorbing conductive slurry into the patterned grid grooves by adopting a blade coating technology to manufacture the shielding film.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.