Shielding film and method of manufacturing same

A shielding film includes an insulation layer, a conductive shielding layer and an adhesive layer; and is manufactured in a method including the steps of connecting a conductive shielding layer to a substrate material and forming a plurality of cavities on them; forming an insulation layer on the conductive shielding layer to fill up all the cavities; forming a carrier film on a top of the insulation layer; removing the substrate material from the conductive shielding layer, such that a plurality of downward protruded metal grounding electrodes are formed on a lower side of the conductive shielding layer corresponding to the cavities; and providing an adhesive layer on the lower side of the conductive shielding layer, such that the metal grounding electrodes are exposed from the adhesive layer to present a geometric pattern. The produced shielding film shows good grounding effect and bonding strength to ensure enhanced electromagnetic shielding effect.

FIELD OF THE INVENTION

The present invention relates to a shielding film and a manufacturing method thereof, and more particularly, to a shielding film that is manufactured in a specific method to provide good grounding effect and enhanced electromagnetic shielding effect.

BACKGROUND OF THE INVENTION

In response to consumers' demands, the currently designed electronic and communication products all are small in volume, light in weight and powerful in function.

However, to meet the above requirements in design, the currently available electronic and communication products also have densely arranged high-frequency clock electric circuits. This condition inevitably worsens the electromagnetic radiation problem and results in electromagnetic interference (EMI) among different electronic products or even has bad influence on users' health.

In the past, engineers tried to solve the problem of electromagnetic radiation with specially designed and planned circuits. This solution, however, requires relatively long time and high cost to achieve the purpose of EMI prevention. To overcome the above disadvantage, a new way has been developed recently to use a shielding film on the electronic product to shield electromagnetic wave. Since the shielding film has the advantage of being convenient to use and low in cost, and it is not necessary to re-design the products for using with the shielding film, the shielding film has been quickly and widely adopted by the electronic industry for EMI prevention.

According to the principle of the shielding film, shielding layers having good electric conductivity are attached to upper and lower surfaces of electronic working elements in the electronic product and are electrically connected to the grounding circuit of the product. When the electromagnetic radiation reaches the shielding layer, an electromagnetic interaction occurs, and electromagnetic energy is absorbed by the grounding circuit, so that the shielding layer has the effect of shielding electromagnetic radiation.

The electric conduction between the shielding layer and the grounding circuit of the electronic working elements has direct influence on the electromagnetic shielding effect of the shielding layer. When the grounding circuit has a relatively small contact resistance while the electromagnetic interaction is relatively strong, better shielding effect can be obtained.

FIG. 1shows the structure of a conventional shielding film1includes an insulation layer11, a shielding layer12and a conductive adhesive layer13. The insulation layer11stops the conductive shielding layer12from contacting with electronic elements. The conductive adhesive layer13includes an adhesive agent having conductive particles13aadded thereto. The conductive particles13aelectrically connect the shielding layer12to the grounding circuit of the electronic elements, and the conductive adhesive layer13is heat cured. With these arrangements, the shielding film1can be fixedly attached to electronic elements to achieve the purpose of shielding electromagnetic wave.

However, in the conventional shielding film1shown inFIG. 1, while the conductive adhesive layer13having the conductive particles13aadded thereto can provide bonding and electrical conducting functions at the same time, the large contact resistance among the conductive particles13atends to result in lowered electric conduction and accordingly indirectly affects the intended shielding effect. Further, the size uniformity, the degree of dispersion and the settling of the conductive particles13aall have influence on the electric conduction and the adhesion of the shielding film1to thereby lower the shielding effect thereof.

In view of the disadvantages in the conventional shielding film, it is desirable to develop an improved shielding film having excellent electromagnetic shielding function and a method for efficiently manufacturing such shielding film through simplified procedures at reduced cost.

SUMMARY OF THE INVENTION

A primary object of the present invention is to provide a shielding film that includes an adhesive layer to fill up a relatively large area of spaces formed among a plurality of metal grounding electrodes below a conductive shielding layer. Since no conductive particles are added to the adhesive layer, the problem of low electrical conduction due to high contact resistance among the conductive particles is avoided, and the shielding film can provide good grounding effect.

Another object of the present invention is to provide a shielding film, an adhesive layer of which has good bonding strength because no conductive particles are added thereto to adversely affect the adhesion of the adhesive layer.

A further object of the present invention is to provide a method of manufacturing shielding film, so that the shielding film manufactured in the method has high electric conduction property and good bonding strength to provide good shielding effect. Further, the shielding film manufacturing method of the present invention has simplified procedures to enable reduced manufacturing cost and increased industrial applicability.

To achieve the above and other objects, the shielding film according to the present invention includes:

an insulation layer; at least one conductive shielding layer located on a lower side of the insulation layer; and an adhesive layer located on a lower side of the conductive shielding layer. A part area of the conductive shielding layer is downward protruded to form a plurality of metal grounding electrodes, which are distributed over the lower side of the conductive shielding layer and together present a geometric pattern to define a plurality of relatively large filling spaces among them. The adhesive layer fills up the filling spaces.

The insulation layer can be a simple structure formed of a first insulation material, or a composite structure formed of a first insulation material and a bonding material.

In a first embodiment of the present invention, the conductive shielding layer includes at least one metal shielding material located below and connected to the insulation layer, and the metal grounding electrodes are provided on a lower side of the metal shielding material.

In a second embodiment of the present invention, the conductive shielding layer includes at least one metal shielding material located below and connected to the insulation layer, and the metal shielding material is partially downward protruded to form the metal grounding electrodes.

In a third embodiment of the present invention, the insulation layer includes a plurality of first protruded portions formed on a lower side thereof, and the conductive shielding layer includes at least one metal shielding material located below and connected to the insulation layer; and portions of the metal shielding layer corresponding to the first protruded portions of the insulation layer form the metal grounding electrodes.

In an operable embodiment, the conductive shielding layer further includes a weatherproof layer.

In a preferred embodiment, the conductive shielding layer further includes at least one second insulation material, which is located between and connected to two adjacent layers of the metal shielding material.

According to the present invention, the bonding material can be nickel (Ni), tin (Sn), zinc (Zn), silver (Ag), copper (Cu), aluminum (Al), titanium (Ti), chromium (Cr), molybdenum (Mo), tungsten (W), iron (Fe), vanadium (V), cobalt (Co), niobium (Nb), a polymeric material, any combination of the aforesaid materials, or any oxide of the aforesaid materials.

According to the present invention, the metal shielding material has a thickness ranged between 0.1 μm and 15 μm; and the metal shielding material can be copper (Cu), silver (Ag), aluminum (Al), nickel (Ni), zinc (Zn), tin (Sn), iron (Fe), carbon (C), graphite, graphene, an electrically conductive polymeric material, or any combination thereof.

According to the present invention, the metal grounding electrodes have a height ranged between 3 μm and 30 μm; and the metal grounding electrodes can be formed of copper (Cu), silver (Ag), aluminum (Al), nickel (Ni), zinc (Zn), tin (Sn), iron (Fe), carbon (C), graphite, graphene, or any combination thereof.

In a fourth embodiment of the present invention, the shielding film includes an insulation layer containing particles of at least one type of electrically insulating, heat conductive material; a conductive shielding layer located below the insulation layer and having a part area downward protruded to form a plurality of metal grounding electrodes, which together present a geometric pattern to define a plurality of relatively large filling spaces among the metal grounding electrodes; and an adhesive layer filled in the filling spaces and containing metal particles.

In a fifth embodiment of the present invention, the shielding film includes a conductive shielding layer, a part area of which is downward protruded to form a plurality of metal grounding electrodes, which together present a geometric pattern to define a plurality of relatively large filling spaces among the metal grounding electrodes; and an adhesive layer filled in the filling spaces.

To achieve the above and other objects, a preferred embodiment of the method of manufacturing shielding film according to the present invention include the steps of (A) connecting a conductive shielding layer to a top of a substrate material, and forming a plurality of cavities on the substrate material and the conductive shielding layer; (B) forming an insulation layer on a top of the conductive shielding layer, such that the insulation layer fills up all the cavities; (C) forming a carrier film on a top of the insulation layer; (D) removing the substrate material from the conductive shielding layer, such that a plurality of downward protruded metal grounding electrodes are formed on a lower side of the conductive shielding layer corresponding to the cavities; and (E) providing an adhesive layer on the lower side of the conductive shielding layer, such that the metal grounding electrodes distributed over the lower side of the conductive shielding layer are exposed from the adhesive layer to present a geometric pattern.

According to a first operable embodiment of the method of the present invention, in the step (A), the cavities are formed on the substrate material through hot stamping; and the conductive shielding layer is then formed on a top of the substrate material and in the cavities.

According to a second operable embodiment of the method of the present invention, in the step (A), the conductive shielding layer is formed on a top of the substrate material; and then, the substrate material and the conductive shielding layer are hot stamped at the same time to form the cavities.

According to a third operable embodiment of the method of the present invention, in the step (A), the cavities are formed on the substrate material through hot stamping; a layer of electrically conductive material is then formed on a top of the substrate material and the electrically conductive material is subjected to a surface passivation treatment; and the conductive shielding layer is formed on a top of the electrically conductive material.

The present invention is characterized in that, by forming the conductive shielding layer and the metal grounding electrodes and by filling the adhesive layer in the large area of filling spaces among the metal grounding electrodes, the shielding film of the present invention has good electrical conduction property and accordingly, provides enhanced electromagnetic shielding effect. And, with the above arrangements, it is not necessary to add conductive particles to the adhesive layer, enabling the adhesive layer in the present invention to have increased bonding strength. Further, the shielding film manufacturing method of the present invention has simplified procedures to enable reduced manufacturing cost and increased industrial applicability.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described with some preferred embodiments thereof and by referring to the accompanying drawings. For the purpose of easy to understand, elements that are the same in the preferred embodiments are denoted by the same reference numerals.

Please refer toFIG. 2Athat is a vertical sectional view showing the structure of a shielding film2according to a first embodiment of the present invention includes an insulation layer21, at least one electrically conductive shielding layer22, and an adhesive layer24.

As can be seen inFIG. 2A, the insulation layer21is a simple structure formed of a first insulation material21a, which has a thickness ranged between 5 μm and 25 μm and can be at least one of polyimide (PI), polyethylene terephthalate (PET), polycarbonate (PC), and polyphenylsulfone (PPSU). Preferably, the first insulation material21ahas a black color for the shielding film2of the present invention to provide even better electromagnetic shielding effect.

The conductive shielding layer22is connected at an upper side to a lower side of the insulation layer21and is formed of a metal shielding material221. The metal shielding material221has a thickness ranged between 0.1 μm and 15 μm, and can be at least one of copper (Cu), silver (Ag), aluminum (Al), nickel (Ni), zinc (Zn), tin (Sn), iron (Fe), carbon (C), graphite, graphene, and an electrically conductive polymeric material.

As shown inFIG. 2A, a plurality of metal grounding electrodes222is provided on a lower side of the metal shielding material221to protrude in a direction opposite to the first insulation material21a. The metal grounding electrodes222respectively have a height ranged between 3 μm and 30 μm, and can be formed of at least one of copper (Cu), silver (Ag), aluminum (Al), nickel (Ni), zinc (Zn), tin (Sn), iron (Fe), carbon (C), graphite and graphene.

The metal grounding electrodes222distributed over the lower side of the metal shielding material221together present a geometric pattern on the lower side of the conductive shielding layer22. The patterned metal grounding electrodes222define a plurality of relatively large filling spaces23among them, and the filling spaces23account for about 65% to 99% of a total area of the conductive shielding layer22. The adhesive layer24is filled in the filling spaces23.

The adhesive layer24can be at least one of a thermosetting epoxy resin, acrylic acid, polyurethane, and polyimide.

Please refer toFIG. 2B. According to the first embodiment of the shielding film2, the insulation layer21can be a composite material formed of the first insulation material21aand a bonding material21blocated between the first insulation material21aand the metal shielding material221. The bonding material21bhas a thickness ranged between 0.01 μm and 10 μm, and can be formed of at least one of nickel (Ni), tin (Sn), zinc (Zn), silver (Ag), copper (Cu), aluminum (Al), titanium (Ti), chromium (Cr), molybdenum (Mo), tungsten (W), iron (Fe), vanadium (V), cobalt (Co), niobium (Nb) and a polymeric material, or can be an oxide of at least one of the aforesaid materials. Further, the conductive shielding layer22further includes a weatherproof layer223covering surfaces of the metal grounding electrodes222. The weatherproof layer223has a thickness ranged between 0.005 μm and 1 μm, and can be at least one of nickel (Ni), tin (Sn), zinc (Zn), silver (Ag), copper (Cu), aluminum (Al), titanium (Ti), chromium (Cr), molybdenum (Mo), tungsten (W), iron (Fe) and vanadium (V), or can be an oxide of at least one of the aforesaid metal materials.

According to the first embodiment of the shielding film2shown inFIG. 2B, the conductive shielding layer22can include multiple layers of the metal shielding material221, as shown inFIG. 2C.

According to the first embodiment of the shielding film2shown inFIG. 2B, the weatherproof layer223can be further formed on one or both of the upper and the lower side of the metal shielding material221, as shown inFIG. 2D.

According to the first embodiment of the shielding film2shown inFIG. 2C, at least one second insulation material224can be further provided in the conductive shielding layer22to locate between two adjacent metal shielding layers221, as shown inFIG. 2E.

FIG. 3Ais a vertical sectional view showing the structure of a shielding film2according to a second embodiment of the present invention includes an insulation layer21, at least one electrically conductive shielding layer22, and an adhesive layer24. The conductive shielding layer22includes a metal shielding material221connected at an upper side to a lower side of the insulation layer21. A part area of the metal shielding material221is downward protruded to form a plurality of metal grounding electrodes222, which together present a geometric pattern to define a plurality of filling spaces23among them, and the adhesive layer24is filled in the filling spaces23.

Please refer toFIG. 3B. According to the second embodiment of the shielding film2, the insulation layer21can further include a bonding material21b, and the conductive shielding layer22can further include a weatherproof layer223to cover a lower side of the metal shielding material221. Then, the adhesive layer24is formed in the filling spaces23defined among the metal grounding electrodes222.

According to the second embodiment of the shielding film2shown inFIG. 3B, the conductive shielding layer22can include multiple layers of the metal shielding material221, as shown inFIG. 3C.

According to the second embodiment of the shielding film2shown inFIG. 3B, the weatherproof layer223can be further formed on one or both of the upper and the lower side of the metal shielding material221, as shown inFIG. 3D.

According to the second embodiment of the shielding film2shown inFIG. 3C, at least one second insulation material224can be further provided in the conductive shielding layer22to locate between two adjacent metal shielding layers221, as shown inFIG. 3E.

FIG. 4Ais a vertical sectional view showing the structure of a shielding film2according to a third embodiment of the present invention includes an insulation layer21, at least one electrically conductive shielding layer22, and an adhesive layer24. A part area of the insulation layer21is downward extended from a lower side thereof to form a plurality of first protruded portions21c; and the conductive shielding layer22includes a metal shielding material221connected to the lower side of the insulation layer21. Portions of the metal shielding material221corresponding to the downward first protruded portions21crespectively form a metal grounding electrode222. The metal grounding electrodes222together present a geometric pattern to define a plurality of filling spaces23among them, and the adhesive layer24is filled in the filling spaces23.

Please refer toFIG. 4B. According to the third embodiment of the shielding film2, the insulation layer21can further include a bonding material21b, and the conductive shielding layer22can further include a weatherproof layer223to cover a lower side of the metal shielding material221. Then, the adhesive layer24is formed in the filling spaces23defined among the metal grounding electrodes222.

According to the third embodiment of the shielding film2shown inFIG. 4B, the conductive shielding layer22can include multiple layers of the metal shielding material221, as shown inFIG. 4C.

According to the third embodiment of the shielding film2shown inFIG. 4B, the weatherproof layer223can be further formed on one or both of the upper and the lower side of the metal shielding material221, as shown inFIG. 4D.

According to the third embodiment of the shielding film2shown inFIG. 4C, at least one second insulation material224can be further provided in the conductive shielding layer22to locate between two adjacent metal shielding layers221, as shown inFIG. 4E.

FIGS. 5A to 5Care vertical sectional views showing the structure of a shielding film2according to a fourth embodiment of the present invention includes an insulation layer21, an electrically conductive shielding layer22, and an adhesive layer24. A part area of the conductive shielding layer22is downward protruded to form a plurality of metal grounding electrodes222, which together present a geometric pattern on the lower side of the conductive shielding layer22. The patterned metal grounding electrodes222define a plurality of relatively large filling spaces23among them, and the adhesive layer24is filled in the filling spaces23. In the insulation layer21, particles21eof at least one type of electrically insulating, heat conductive material are added. The electrically insulating, heat conductive material can be aluminum oxide (Al2O3), aluminum nitride (AlN), boron nitride (BN), silicon carbide (SiC), magnesium oxide (MgO), zinc oxide (ZnO), nickel oxide (NiO), Silicon dioxide (SiO2), silicon nitride (Si3N4), powder carbon (C), or a polymer-based insulating heat-conductive material. And, in the adhesive layer24, metal particles24aare contained.

In the fourth embodiment, the conductive shielding layer22includes a metal shielding material221connected at an upper side to a lower side of the insulation layer21, and the downward protruded metal grounding electrodes222are provided on a lower side of the metal shielding material221, as shown inFIG. 5A. According to the fourth embodiment, the conductive shielding layer22can include multiple layers of the metal shielding material221, similar to that shown inFIG. 2C; or one or more weatherproof layers223can be further formed on one or both of the upper and the lower side of the metal shielding material221, similar to that shown inFIG. 2D; or at least one second insulation material224can be further provided in the conductive shielding layer22to locate between two adjacent metal shielding layers221, similar to that shown inFIG. 2E.

Please refer toFIG. 5B. According to a first variant of the fourth embodiment, the conductive shielding layer22includes a metal shielding material221connected at an upper side to a lower side of the insulation layer21, and a part area of the metal shielding material221is downward protruded to form a plurality of metal grounding electrodes222. According to this first variant, the conductive shielding layer22can include multiple layers of the metal shielding material221, similar to that shown inFIG. 3C; or one or more weatherproof layers223can be further formed on one or both of the upper and the lower side of the metal shielding material221, similar to that shown inFIG. 3D; or at least one second insulation material224can be further provided in the conductive shielding layer22to locate between two adjacent metal shielding layers221, similar to that shown inFIG. 3E.

Please refer toFIG. 5C. According to a second variant of the fourth embodiment, a part area of the insulation layer21is downward extended from a lower side thereof to form a plurality of first protruded portions21c; and the conductive shielding layer22includes a metal shielding material221connected to the lower side of the insulation layer21. Portions of the metal shielding material221corresponding to the downward first protruded portions respectively form a metal grounding electrode222. According to this second variant, the conductive shielding layer22can include multiple layers of the metal shielding material221, similar to that shown inFIG. 4C; or one or more weatherproof layers223can be further formed on one or both of the upper and the lower side of the metal shielding material221, similar to that shown inFIG. 4D; or at least one second insulation material224can be further provided in the conductive shielding layer22to locate between two adjacent metal shielding layers221, similar to that shown inFIG. 4E.

In the fourth embodiment and the variants thereof, with the metal grounding electrodes222, the insulation layer21containing particles21eof at least one electrically insulating, heat conductive material, and the adhesive layer24containing metal particles24a, the shielding film2of the present invention provides not only good grounding effect, but also good heat dissipation effect.

FIGS. 6A to 6Care vertical sectional views showing the structure of a shielding film2according to a fifth embodiment of the present invention includes an electrically conductive shielding layer22, and an adhesive layer24. A part area of the conductive shielding layer22is downward protruded to form a plurality of metal grounding electrodes222, which together present a geometric pattern on the lower side of the conductive shielding layer22. The patterned metal grounding electrodes222define a plurality of relatively large filling spaces23among them, and the adhesive layer24is filled in the filling spaces23.

In the fifth embodiment, as shown inFIG. 6A, the conductive shielding layer22includes a metal shielding material221, and the downward protruded metal grounding electrodes222are located on a lower side of the metal shielding material221, According to the fifth embodiment, the conductive shielding layer22can include multiple layers of the metal shielding material221, similar to that shown inFIG. 2C; or one or more weatherproof layers223can be further formed on one or both of the upper and the lower side of the metal shielding material221, similar to that shown inFIG. 2D; or at least one second insulation material224can be further provided in the conductive shielding layer22to locate between two adjacent metal shielding layers221, similar to that shown inFIG. 2E.

Please refer toFIG. 6B. According to a first variant of the fifth embodiment, the conductive shielding layer22includes a metal shielding material221, and a part area of the metal shielding material221is downward protruded to form a plurality of metal grounding electrodes222. According to this first variant, the conductive shielding layer22can include multiple layers of the metal shielding material221, similar to that shown inFIG. 3C; or one or more weatherproof layers223can be further formed on one or both of the upper and the lower side of the metal shielding material221, similar to that shown inFIG. 3D; or at least one second insulation material224can be further provided in the conductive shielding layer22to locate between two adjacent metal shielding layers221, similar to that shown inFIG. 3E.

Please refer toFIG. 6C. According to a second variant of the fifth embodiment, the conductive shielding layer22includes a metal shielding material221, which is formed into a plurality of metal grounding electrodes222. According to this second variant, the conductive shielding layer22can include multiple layers of the metal shielding material221, similar to that shown inFIG. 4C; or one or more weatherproof layers223can be further formed on one or both of the upper and the lower side of the metal shielding material221, similar to that shown inFIG. 4D; or at least one second insulation material224can be further provided in the conductive shielding layer22to locate between two adjacent metal shielding layers221, similar to that shown inFIG. 4E.

According to the fifth embodiment, the shielding film2of the present invention does not necessarily include an insulation layer21and can be directly attached to an enclosure of an electronic product. In this manner, the electromagnetic wave generated by the electronic product can be shielded by the metal shielding layer221and grounded via the metal grounding electrodes222of the shielding film2to achieve good grounding effect.

In the fifth embodiment, the bonding material21band the weatherproof layer23can be provided according to the requirements of the manufacturing process of the shielding film2. That is, the bonding material21band the weatherproof layer23can be omitted at the same time, or only the bonding material21bis provided, or only the weatherproof layer223is provided, or the bonding material21band the weatherproof layer223can be provided at the same time.

FIGS. 7A to 7Care vertical sectional views showing some possible geometric shapes for the configurations of the metal grounding electrodes222of the conductive shielding layer22according to the present invention. InFIG. 7A, the metal grounding electrodes222have a rectangular cross section. InFIG. 7B, the metal grounding electrodes222have a trapezoidal cross section. InFIG. 7C, the metal grounding electrodes222have an inverted pyramid cross section.

FIGS. 8A to 8Dare top views showing some different geometric patterns that can be presented by the metal grounding electrodes222on the conductive shielding layer22for the shield film2of the present invention. In any one of these geometric patterns, the filling spaces23defined among the metal grounding electrodes222are always filled up by the adhesive layer24. InFIG. 8A, the metal grounding electrodes222are arranged in a plurality of straight rows. InFIG. 8B, the metal grounding electrodes222are arranged in a plurality of round posts. InFIG. 8C, the metal grounding electrodes222are arranged in a diamond-shaped grid. InFIG. 8D, the metal grounding electrodes222are arranged in a hexagon-shaped grid.

The present invention also provides a method of manufacturing a shielding film2. Please refer toFIG. 9that is a flowchart showing the steps included in a first embodiment of the shielding film manufacturing method of the present invention, and toFIG. 10that is a pictorial description of the steps in the flowchart ofFIG. 9. The following is a detailed description of these steps, which are numbered from (A) to (E) herein for ease of reference.

Step (A): Form a plurality of cavities on a substrate material25through hot stamping on an embossing machine, and then form an electrically conductive shielding layer22on a top of the substrate material25and the cavities through sputtering deposition on a sputtering machine, or through vapor deposition or chemical deposition on a vapor deposition machine, such that the substrate material25and the conductive shielding layer22are connected to each other and correspondingly form a cavity-showing pattern having a plurality of cavities. Wherein, the hot stamping is performed on the embossing machine at a temperature from about 100 to about 200° C.

Step (B): Form an insulation layer21on a top of the conductive shielding layer22using a coating machine, such that the insulation layer21fills up the cavities. The insulation layer21can be a simple structure formed of a first insulation material21aor a composite structure formed of a first insulation material21aand a bonding material21blocated below the first insulation material21a.

Step (C): Form a carrier film26on a top of the insulation layer21. The carrier film26can be polyethylene terephthalate (PET), which will be removed when the shielding film2is ready for use.

Step (D): Remove the substrate material25from a lower side of the conductive shielding layer22, so as to expose the cavity-showing pattern formed in the step (A) through hot stamping on the embossing machine. The cavity-showing pattern is downward protruded from the lower side of the conductive shielding layer22to form a plurality of metal grounding electrodes222, among which a plurality of filling spaces23is defined.

Step (E): Fill an adhesive layer24in the filling spaces23, such that the metal grounding electrode222is exposed from the lower side of the conductive shielding layer22to present a geometric pattern.

Please refer toFIG. 11. According to an operable embodiment, a step can be further included after the steps (A) to (E) of the first embodiment: Provide a release material3on the adhesive layer24and the exposed surfaces of the metal grounding electrodes222to protect and beautify an appearance of a finished product of the shielding film2.

Please refer toFIG. 12that is a flowchart showing the steps included in a second embodiment of the shielding film manufacturing method of the present invention, and toFIG. 13that is a pictorial description of the steps in the flowchart ofFIG. 12. Since the second embodiment of the method of the present invention is different from the first embodiment only in the step (A) while all other steps thereof from (B) to (E) are the same as those in the first embodiment, only the step (A) is described in detail herein. Step (A): Provide a substrate material25, and form a conductive shielding layer22on a top of the substrate material25through vapor deposition, sputtering deposition or chemical deposition, so that the substrate material and the conductive shielding layer22are connected to each other. Then, form a plurality of cavities on the connected substrate material25and conductive shielding layer22through hot stamping on an embossing machine, such that the substrate material25and the conductive shielding layer22correspondingly form a cavity-showing pattern having a plurality of cavities.

Please refer toFIG. 14that is a flowchart showing the steps included in a third embodiment of the shielding film manufacturing method of the present invention, and toFIG. 15that is a pictorial description of the steps in the flowchart ofFIG. 14. Since the third embodiment of the method of the present invention is different from the second embodiment only in the step (A), only the step (A) is described in detail herein. Step (A): Form a cavity-showing pattern directly on a substrate material25through hot stamping on an embossing machine, wherein the substrate material is a repeatedly usable master template; and then, form a layer of electrically conductive material27on a top of the substrate material25through vapor deposition, sputtering deposition or chemical deposition. The electrically conductive material27is a metal material. Thereafter, subject the electrically conductive material27to a surface passivation treatment for changing the surface state of the metal material to a corrosion-resistant passive state. At this point, a thin film, i.e. a passivation film, is formed on the surface of the metal material. In industrial applications, a passivating agent, mainly an oxidizing agent, is usually used in the metal passivation treatment to form a layer of protection film on the metal surface. For instance, cold concentrated sulfuric acid and cold concentrated nitric acid can be used in the passivation treatment for iron and aluminum. According to the present invention, through the passivation treatment, the electrically conductive material27can be easily separated from the layer with which the electrically conductive material27is in contact and the substrate material25can have increased durability.

Finally, also in the step (A), form a conductive shielding layer22on a top of the electrically conductive material27through sputtering deposition, chemical deposition or electroplating. Among others, electroplating process is a high-efficiency and high-precision forming technique. By utilizing the principle of electroplating deposition and externally supplied electric energy, a mixed solution containing metal ions and other additives is caused to react with a cathode or an anode, so that electrochemical oxidation and reduction reactions take place at the anode and the cathode, respectively, to deposit desired metal on the surface of a given object. Since all other steps (B) to (E) of the third embodiment are the same as those in the first and second embodiments, they are not repeatedly described herein.

FIG. 16is a flowchart showing the steps included in a fourth embodiment of the shielding film manufacturing method of the present invention, andFIG. 17is a pictorial description of the steps in the flowchart ofFIG. 16. The following is a detailed description of these steps, which are numbered from (A) to (D) herein for ease of reference. Step (A): provide an insulation layer21; step (B): form a conductive shielding layer22on a lower side of the insulation layer21through vapor deposition, sputtering deposition or chemical deposition; step (C): subject the insulation layer21and the conductive shielding layer22to a hot stamping process on an embossing machine at the same time, so that they together form a plurality of downward protruded metal grounding electrodes222; and step (D): fill an adhesive layer24in filling spaces23formed on a lower side of the conductive shielding layer22among the metal grounding electrodes222, such that the metal grounding electrodes222are exposed from the adhesive layer24to present a geometric pattern.

FIG. 18is a flowchart showing the steps included in a fifth embodiment of the shielding film manufacturing method of the present invention, andFIG. 19is a pictorial description of the steps in the flowchart ofFIG. 18. The following is a detailed description of these steps, which are numbered from (A) to (C) herein for ease of reference.

Step (A): Provide a first insulation material21a; coat a polymeric material21don a lower side of the first insulation layer21ausing a coating machine and pre-cure the polymeric material21d; form a pattern on a lower side of the polymeric material21dthrough hot stamping, so that the first insulation material21aand the patterned polymeric material21dtogether constitute an insulation layer21; form a plurality of downward protruded portions on the insulation layer21corresponding to the pattern formed on the polymeric material21d; and irradiate ultraviolet (UV) light to the polymeric material21dor heat-dry the polymeric material21din an oven for the polymeric material21dto fully cure and be shaped.

Step (B): Form a conductive shielding layer22on a lower side of the insulation layer21, such that portions of the conductive shielding layer22corresponding to the downward protruded portions of the insulation layer21form a plurality of metal grounding electrodes222.

Step (C): Provide an adhesive layer24on a lower side of the conductive shielding layer22with the metal grounding electrodes222exposed from the adhesive layer24to present a geometric pattern.

FIG. 20is a flowchart showing the steps included in a sixth embodiment of the shielding film manufacturing method of the present invention, andFIG. 21is a pictorial description of the steps in the flowchart ofFIG. 20. These steps are numbered from (A) to (C) herein for ease of reference. Step (A): Provide a first insulation material21a; form a pattern on a polymeric material21dthrough transfer printing or screen printing and provide the patterned polymeric material21don a lower side of the first insulation material21a, so that the first insulation material21aand the patterned polymeric material21dtogether constitute an insulation layer21; form a plurality of downward protruded portions on a lower side of the insulation layer21; and irradiate ultraviolet (UV) light to the polymeric material21dor heat-dry the polymeric material21din an oven for the polymeric material21dto fully cure and be shaped.

Since the steps (B) and (C) in the sixth embodiment are similar to those in the fifth embodiment, they are not repeatedly described herein.

FIG. 22is a flowchart showing the steps included in a seventh embodiment of the shielding film manufacturing method of the present invention, andFIGS. 23 and 24are a pictorial description of the steps in the flowchart ofFIG. 21. The following is a detailed description of these steps, which are numbered from (A) to (C) herein for ease of reference.

Step (A): Form a conductive shielding layer22through calendering or electroplating, and form a plurality of downward protruded portions on the conductive shielding layer22, so that the downward protruded portions respectively form a metal grounding electrode222.

Step (B): Form an insulation layer21on a top of the conductive shielding layer22.

Step (C): Provide an adhesive layer24on a lower side of the conductive shielding layer22opposite to the insulation layer21, while the metal grounding electrodes222are exposed from the adhesive layer24to present a geometric pattern.

In the seventh embodiment, the conductive shielding layer22provided in the step (A) can be subjected to a hot stamping process on an embossing machine to form the plurality of downward protruded portions, as shown inFIG. 23.

According to a variant of the seventh embodiment, the conductive shielding layer22provided in the step (A) can be shaped in a mold having a plurality of cavities, so as to form a plurality of downward protruded portions on a lower side thereof, as shown inFIG. 24.

Since the above variant is different from the seventh embodiment only in the step (A) for forming the conductive shielding layer22, the steps (B) and (C) for the variant similar to those in the seventh embodiment are not repeatedly described herein. Further, in the variant of the seventh embodiment shown inFIG. 24, there is not any weatherproof layer223formed on the conductive shielding layer22. However, according to another operable embodiment, although not shown in the drawings, a weatherproof layer223can be formed on outer surfaces of the metal grounding electrodes222through electroplating.

In all the first to the seventh embodiment of the method of the present invention, the insulation layer21can be a simple structure formed of a first insulation material21aor a composite structure formed of the first insulation material21aand a bonding material21blocated on a lower side of the first insulation material21a; and the weatherproof layer223of the conductive shielding layer22can be formed according to actual requirement in use. In an operable embodiment, only a single weatherproof layer223is formed on the surfaces of the metal grounding electrodes222, as shown inFIGS. 2C, 3C and 4C. In another operable embodiment, additional weatherproof layers223can be further formed on the upper side and the lower side of the metal shielding material221of the conductive shielding layer22through sputtering deposition, electroplating or chemical deposition, as shown inFIGS. 2D, 3D and 4D. And, in the method of manufacturing the shielding film2, a further step can be included after other steps to provide a release material3on the surfaces of the adhesive layer24and the metal grounding electrodes222(seeFIG. 11), so as to protect and beautify the appearance of a finished product of the shielding film2.

The following table compares the structure of the shielding film2manufactured in the method of the present invention (Exp 1-6) with the structure of the conventional shielding film1shown inFIG. 1(Comp 1-2). And, as can be seen from the table, the shielding film2of the present invention is superior to the conventional shielding film1in terms of grounding effect and bonding strength.

In summary, by forming the conductive shielding layer and the metal grounding electrodes and by filling the adhesive layer in the large area of filling spaces defined among the metal grounding electrodes, the shielding film of the present invention avoids the problems of the conventional shielding film as having high contact resistance among the conductive particles added to the conductive adhesive layer. Therefore, the shielding film of the present invention has good electrical conduction property and accordingly, provides enhanced electromagnetic shielding effect.