Shielding film and method for making the same

Abstract

The present invention discloses a shielding film, including a shielding area including a plurality of metal wires formed by micro-electroforming, and a buffer area formed by micro-electroforming, connected to at least one side of the shielding area, and used to reduce the overall thickness difference of the shielding area. The present invention also discloses a method for making a shielding film, the method comprising: providing a curing adhesive layer having a shielding area graphic groove and a buffer area graphic groove connected to the shielding area graphic groove; preparing a shielding area and a buffer area connected to the shielding area by micro-electroforming in the shielding area graphic groove and the buffer area graphic groove; separating the connected shielding area and the buffer area from the curing adhesive layer to obtain a shielding film. By preparing the shielding area by micro-electroforming and preparing the buffer area on at least one side of the shielding area, the overall thickness difference of the shielding area is small, so that the thickness of the shielding area is relatively uniform, thereby enhancing the electromagnetic shielding effect of the shielding film.

Description

Technical Field

[0001] The present invention relates to the technical field of shielding films, and in particular to a shielding film and a manufacturing method thereof. Background Art

[0002] With the development of LCD, CRT, PDP, EL and other display devices, they are widely used in personal computers, mobile phones, public information displays, and for information display and interaction. These electronic display devices also bring more and more electromagnetic interference problems.

[0003] In recent years, metal mesh films have been widely used in electromagnetic signal shielding. Commonly used production methods include sputtering, etching and silver complex salt diffusion. These methods are complex, have low production efficiency, and generally have low transmittance.

[0004] At present, UV embossing and micro-electroforming methods are used to make metal mesh films. The production process is simple, mature, and efficient. The metal mesh film is hollowed out and has high transmittance. However, due to the edge effect of the existing micro-electroforming technology, the different growth rates of the metal lead to large differences in thickness, resulting in uneven electromagnetic shielding capabilities.

[0005] The preceding description is intended to provide general background information and does not necessarily constitute prior art. Summary of the invention

[0006] The object of the present invention is to provide a shielding film and a manufacturing method thereof for reducing the thickness difference of the shielding area.

[0007] The present invention provides a shielding film, comprising a shielding area formed by micro-electroforming and comprising a plurality of metal wires, and a buffer zone formed by micro-electroforming and connected to at least one side of the shielding area for reducing the overall thickness difference of the shielding area.

[0008] In one embodiment, the width of the buffer area is greater than the width of the metal line in the shielding area.

[0009] In one embodiment, the width of the metal line in the shielding area is 3-10 μm, and the width of the buffer area is 0.5-2 cm.

[0010] In one embodiment, the thickness of the shielding area is smaller than that of the buffer area, and the difference in thickness between the shielding area and the buffer area is less than or equal to 3 μm. The thickness of the buffer area is 5-20 μm, and the thickness of the shielding area is 2-17 μm.

[0011] In one embodiment, the shielding area is provided with a first conductive layer and a second conductive layer arranged on the first conductive layer, the buffer area is provided with a first metal layer and a second metal layer arranged on the first metal layer, the first conductive layer is connected to the first metal layer, and the second conductive layer is connected to the second metal layer.

[0012] In one embodiment, the thickness of the second conductive layer is greater than that of the first conductive layer, and the thickness of the second metal layer is greater than that of the first metal layer.

[0013] In one embodiment, the first conductive layer and the first metal layer are made of the same material, the second conductive layer and the second metal layer are made of the same material, the first conductive layer and the first metal layer are made of a paste of silver, copper, gold, graphene, or other conductive materials, and the second conductive layer and the second metal layer are made of silver, copper, gold, nickel, iron-nickel alloy, or other metal materials.

[0014] In one embodiment, a contact surface between the first conductive layer and the second conductive layer is a plane or a non-plane, and a contact surface between the first metal layer and the second metal layer is a plane or a non-plane.

[0015] In one embodiment, the buffer zone is disposed around the shielding zone.

[0016] The present invention also provides a method for manufacturing a shielding film, the method comprising:

[0017] Providing a cured adhesive layer having a shielding area pattern groove and a buffer area pattern groove connected to the shielding area pattern groove;

[0018] A shielding area and a buffer area connected to the shielding area are prepared by micro-electroforming in the shielding area pattern groove and the buffer area pattern groove;

[0019] The shielding area and the buffer area connected together are separated from the cured adhesive layer to obtain a shielding film.

[0020] In one embodiment, the specific steps of preparing the shielding area and the buffer area connected to the shielding area include:

[0021] Filling the first metal material into the shielding area pattern groove and the buffer area pattern groove;

[0022] After solidification, a first conductive layer and the first metal layer are formed;

[0023] In the shielding area pattern groove and the buffer area pattern groove, a second metal material is grown on the first conductive layer and the first metal layer by micro-electroforming to form a second conductive layer and a second metal layer.

[0024] In one embodiment, the method for preparing the cured adhesive layer having the shielding area pattern groove and the buffer area pattern groove connected to the shielding area pattern groove comprises:

[0025] providing a substrate;

[0026] Applying a layer of curing glue on the surface of the substrate to form a curing glue layer;

[0027] A shielding area pattern groove and a buffer area pattern groove connected to the shielding area pattern groove are prepared on the cured adhesive layer.

[0028] In one embodiment, the specific steps of preparing the shielding area pattern groove and the buffer area pattern groove connected to the shielding area pattern groove on the cured adhesive layer include:

[0029] Providing a mold having a grid pattern and a buffer pattern, wherein the grid pattern is connected to the buffer pattern;

[0030] Imprinting the mold on the cured adhesive layer;

[0031] After curing, the shielding area pattern groove and the buffer area pattern groove are formed.

[0032] In one embodiment, the width of the metal line in the shielding area is 3-10 μm, and the width of the buffer area is 0.5-2 cm.

[0033] In one embodiment, the buffer zone is disposed around the shielding zone.

[0034] The shielding film provided by the present invention prepares the shielding area by micro-electroforming and prepares the buffer zone on at least one side of the shielding area, so that the overall thickness difference of the shielding area is small, so that the thickness of the shielding area is relatively uniform, thereby enhancing the electromagnetic shielding effect of the shielding film. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the structure of a shielding film according to an embodiment of the present invention;

[0036] Figure 2 for Figure 1 A schematic diagram of the structure from another perspective;

[0037] Figure 3 A flowchart of the steps of a method for manufacturing a shielding film according to an embodiment of the present invention;

[0038] Figure 4 for Figure 3 Specific step flow chart of step S1;

[0039] Figure 5 for Figure 4Specific step flow chart of step S13;

[0040] Figure 6a to Figure 6g This is a process flow chart of a method for manufacturing a shielding film according to an embodiment of the present invention. DETAILED DESCRIPTION

[0041] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0042] Please refer to Figure 1 and Figure 2 The shielding film provided in the embodiment of the present invention includes a shielding area 3 including a plurality of metal wires formed by micro-electroforming, and a buffer zone 4 formed by micro-electroforming and connected to at least one side of the shielding area 3 for reducing the overall thickness difference of the shielding area 3.

[0043] In this embodiment, buffer zones 4 are arranged around the shielding zone 3 .

[0044] The shielding area 3 is provided with a first conductive layer 31 and a second conductive layer 32 disposed on the first conductive layer 31; the buffer area 4 is provided with a first metal layer 41 and a second metal layer 42 disposed on the first metal layer 41. The first conductive layer 31 is connected to the first metal layer 41, and the second conductive layer 32 is connected to the second metal layer 42. The second metal layer 42 is used to reduce the thickness difference between the edge area and the center area of ​​the second conductive layer 32 when preparing the second conductive layer 32.

[0045] The grid shape of the shielding area 3 is a rectangle, a hexagon, a trapezoid, a random polygon or other arbitrary shapes.

[0046] The width of the buffer zone 4 is greater than the width of the metal line 35 in the shielding zone 3; the thickness of the buffer zone 4 is greater than the thickness of the metal line 35 in the shielding zone 3. Specifically, the width of the buffer zone 4 is 0.5-2 cm, the width of the metal line 35 is 3-10 μm; the thickness of the buffer zone 4 is 5-20 μm, and the thickness of the shielding zone 3 is 2-17 μm.

[0047] The first conductive layer 31 and the second conductive layer 32 both include a plurality of metal grid lines 351, and the first conductive layer 31 and the second conductive layer 32 both form a hollow grid structure composed of a plurality of metal grid lines 351. Specifically, the thickness of the first conductive layer 31 is 1-2 μm, and the thickness of the second conductive layer 32 is 1-15 μm.

[0048] The first conductive layer 31 is integrally formed with the first metal layer 41, and the second conductive layer 32 is integrally formed with the second metal layer 42. The first metal layer 41 and the second metal layer 42 are in strip shape.

[0049] Please refer to Figures 3 to 5 , Figure 6a to Figure 6g The embodiment of the present invention further provides a method for manufacturing a shielding film, the method comprising:

[0050] S1: providing a curing adhesive layer 2 having a shielding area pattern groove 21 and a buffer area pattern groove 22 connected to the shielding area pattern groove 21;

[0051] S2: preparing a shielding area 3 and a buffer area 4 connected to the shielding area 3 by micro-electroforming in the shielding area pattern groove 21 and the buffer area pattern groove 22;

[0052] S3: separating the shielding area 3 and the buffer area 4 connected together from the cured adhesive layer 2 to obtain a shielding film.

[0053] In actual operation, during the micro-electroforming process, due to the edge effect of the current, the electric lines tend to concentrate at the edge, and the current density is correspondingly larger; while the electric lines in the middle are relatively sparse, and the current density is relatively small, so the thickness of the electroformed layer there is greater than the thickness of the central area. Therefore, adding the buffer zone 4 is equivalent to increasing the width of the edge area, which is equivalent to increasing the width of the area with relatively large current density, so that the current in this area is dispersed, that is, the current is equivalent to gathering in an area farther away from the previous central area. As a result, the overall thickness of the shielding area 3 tends to be consistent, thereby reducing the overall thickness difference of the shielding area. Furthermore, the width of the buffer zone 4 is correspondingly increased, so that the overall thickness difference of the shielding area 3 is further reduced.

[0054] In this embodiment, the shielding area 3 is surrounded by the buffer area 4. The width of the metal wire 35 in the shielding area 3 is 3-10 μm, and the width of the buffer area 4 is 0.5-2 cm.

[0055] In step S1, the specific steps of preparing the cured adhesive layer 4 having the shielding area pattern groove 21 and the buffer area pattern groove 22 include:

[0056] S11: providing a substrate 1;

[0057] S12: coating a layer of curing adhesive on the surface of the substrate 1 to form a curing adhesive layer 2;

[0058] S13 : preparing a shielding area pattern groove 21 and a buffer area pattern groove 22 connected to the shielding area pattern groove 21 on the cured adhesive layer 2 .

[0059] In step S11 , in order to facilitate the subsequent curing of the curing adhesive, the higher the transparency of the substrate 1 , the better.

[0060] In step S13, the specific steps of preparing the shielding area pattern groove and the buffer area pattern groove include:

[0061] S131: providing a mold 7 having a grid pattern and a buffer pattern, wherein the grid pattern is connected to the buffer pattern;

[0062] S132: Imprinting the mold 7 on the cured adhesive layer 2;

[0063] S133: After curing, shielding area pattern grooves 21 and buffer area pattern grooves 22 are formed.

[0064] In other embodiments, in step S13, the shielding region pattern groove 21 and the buffer region pattern groove 22 may be prepared by developing and etching.

[0065] In step S2, the same first metal material is first filled into the shielding area pattern groove 21 and the buffer area pattern groove 22; after solidification, the first conductive layer 31 and the first metal layer 41 are formed. In the shielding area pattern groove 21 and the buffer area 4 pattern groove, the same second metal material is directly grown on the first conductive layer 31 and the first metal layer 41 by micro-electroforming to form the second conductive layer 32 and the second metal layer 42, and the second conductive layer 32 and the second metal layer 42 are connected together and formed as one piece. Among them, the first conductive layer 31, the second conductive layer 32, the first metal layer 41 and the second metal layer 42 form an integral structure. The thickness of the second conductive layer 32 is greater than the thickness of the first conductive layer 31, and the thickness of the second metal layer 42 is greater than the thickness of the first metal layer 41. Since the thickness of the first conductive layer 31 and the first metal layer 41 is relatively small, the shielding area is prone to grid deformation, breakage and other problems when they are peeled off from the cured adhesive layer 2; and after a layer of metal material is electroformed on the first conductive layer 31 and the first metal layer 41 to form the second conductive layer 32 and the second metal layer 42, it is equivalent to increasing the thickness of the buffer zone and the shielding area, thereby reducing the occurrence of grid deformation, breakage and other problems in the shielding area when they are peeled off from the cured adhesive layer 2, thereby improving product yield and enhancing electromagnetic shielding effectiveness.

[0066] Specifically, the same first metal material is filled into the shielding area pattern groove 21 and the buffer area pattern groove 22 by scraping, and the first metal material is solidified by sintering, so that the first conductive layer 31 and the first metal layer 41 are connected together and formed as one piece. Among them, the width of the first metal layer 41 is greater than the width of the first metal grid line 351 of the first conductive layer 31. Since the shielding area pattern groove 21 and the buffer area pattern groove 22 are connected, the metal materials in the grooves are flush when the same first metal material is scraped into the shielding area pattern groove 21 and the buffer area pattern groove 22 as a whole. The first metal material is a slurry of silver, copper, gold, graphene or other conductive materials, that is, silver, copper, gold or graphene is mixed with organic matter. The second metal material is silver, copper, gold, nickel, iron-nickel alloy or other metal material. Since the purity of the second metal material is higher than that of the first metal material, the surface resistance of the second conductive layer 32 is less than the surface resistance of the first conductive layer 31, that is, the conductivity of the second conductive layer 32 is greater than the conductivity of the first conductive layer 31. Therefore, the conductivity and shielding effect of the shielding film can be greatly improved.

[0067] In other embodiments, when the first metal material is integrally scraped into the shielding area pattern groove 21 and the buffer area pattern groove 22, due to technical differences and other issues in the scraping process, the surfaces of the first conductive layer 31 and the first metal layer 41 may be non-planar, for example, beveled or curved, so that the contact surface between the first conductive layer 31 and the second conductive layer 32 is a plane, beveled or curved, and the contact surface between the first metal layer 41 and the second metal layer 42 is a plane, beveled or curved. Even if the surfaces of the first conductive layer 31 and the first metal layer 41 are non-planar, it will not affect the metal growth on the first conductive layer 31 and the first metal layer 41.

[0068] In this embodiment, the width of the metal line 35 in the shielding area 3 is 3-10 μm, and the width of the buffer area 4 is 0.5-2 cm. The first metal grid lines 351 in the first conductive layer 31 and the second metal grid lines 352 in the second conductive layer 32 form the metal line 35 .

[0069] Therefore, the width of the first metal layer 41 is greater than the width of the first metal grid lines 351 of the first conductive layer 31 , and the width of the second metal layer 42 is also greater than the width of the second metal grid lines 352 of the second conductive layer 32 .

[0070] In this embodiment, the overall thickness difference of the second conductive layer 32 is less than 2 μm.

[0071] That is, the thickness of the second metal layer 42 will be greater than the thickness of the second conductive layer 32, so that the thickness of the buffer zone 4 is greater than the thickness of the shielding zone 3, and thus when the shielding zone 3 and the buffer zone 4 are separated from the cured adhesive layer 2, the grid lines 35 of the shielding zone 3 will not be deformed, and the separation is easier.

[0072] In this embodiment, the thickness of the second metal layer 42 is about 3 μm greater than the thickness of the second conductive layer 32 .

[0073] In step S3, the whole structure is manually separated from the cured adhesive layer 2. By separating the whole structure from the cured adhesive layer 2, the obtained shielding film is a hollow mesh structure, which enhances the light transmittance compared to the shielding film that has not been separated.

[0074] In the accompanying drawings, the sizes and relative sizes of layers and regions are exaggerated for clarity. It should be understood that when an element, such as a layer, region, or substrate, is referred to as being "formed on," "disposed on," or "located on" another element, the element may be disposed directly on the other element, or there may be intervening elements. Conversely, when an element is referred to as being "formed directly on" or "disposed directly on" another element, there are no intervening elements.

[0075] In this document, unless otherwise specified or limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0076] In this document, the directions or positional relationships indicated by terms such as "up", "down", "front", "back", "left", "right", "top", "bottom", "inside", "outside", "vertical", and "horizontal" are based on the directions or positional relationships shown in the accompanying drawings and are only for the clarity of expressing the technical solutions and the convenience of description, and therefore should not be understood as limitations of the present invention.

[0077] In this document, the ordinal adjectives “first”, “second”, etc. used to describe elements are only used to distinguish elements with similar attributes, and do not mean that the elements described in this way must follow a given order, or time, space, level or other limitations.

[0078] As used herein, unless otherwise specified, “plurality” or “several” means two or more.

[0079] In this document, the terms "comprises," "comprising," or any other variations thereof, are intended to cover a non-exclusive inclusion of elements other than those listed and may also include additional elements not expressly listed.

[0080] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A shielding film, characterized in that: It includes a shielding area formed by micro-electroforming and including a plurality of metal wires, and a buffer area formed by micro-electroforming and connected to at least one side of the shielding area to reduce the thickness difference of the shielding area as a whole, wherein the buffer area is arranged around the shielding area; The width of the buffer area is greater than the width of the metal line in the shielding area; The shielding area is provided with a first conductive layer and a second conductive layer arranged on the first conductive layer, the buffer area is provided with a first metal layer and a second metal layer arranged on the first metal layer, the first conductive layer is connected to the first metal layer, and the second conductive layer is connected to the second metal layer; The thickness of the second conductive layer is greater than that of the first conductive layer, and the thickness of the second metal layer is greater than that of the first metal layer.

2. The shielding film according to claim 1, wherein: The width of the metal line in the shielding area is 3-10 μm, and the width of the buffer area is 0.5-2 cm.

3. The shielding film according to claim 1, wherein: The thickness of the shielding area is smaller than that of the buffer area, and the difference in thickness between the shielding area and the buffer area is less than or equal to 3 μm. The thickness of the buffer area is 5-20 μm, and the thickness of the shielding area is 2-17 μm.

4. The shielding film according to claim 1, wherein: The first conductive layer is made of the same material as the first metal layer, the second conductive layer is made of the same material as the second metal layer, the first conductive layer and the first metal layer are made of silver, copper, gold or graphene paste, and the second conductive layer and the second metal layer are made of silver, copper, gold, nickel or iron-nickel alloy.

5. The shielding film according to claim 1, wherein: The contact surface between the first conductive layer and the second conductive layer is a plane or a non-plane, and the contact surface between the first metal layer and the second metal layer is a plane or a non-plane.

6. A method for manufacturing a shielding film, used for manufacturing the shielding film as claimed in claim 1, characterized in that: The method includes: Providing a cured adhesive layer having a shielding area pattern groove and a buffer area pattern groove connected to the shielding area pattern groove; A shielding area and a buffer area connected to the shielding area are prepared by micro-electroforming in the shielding area pattern groove and the buffer area pattern groove; Separating the shielding area and the buffer area connected together from the cured adhesive layer to obtain a shielding film; The buffer zone is arranged around the shielding zone.

7. The method for manufacturing a shielding film according to claim 6, wherein: The specific steps of preparing the shielding area and the buffer area connected to the shielding area include: Filling the first metal material into the shielding area pattern groove and the buffer area pattern groove; After solidification, a first conductive layer and the first metal layer are formed; In the shielding area pattern groove and the buffer area pattern groove, a second metal material is grown on the first conductive layer and the first metal layer by micro-electroforming to form a second conductive layer and a second metal layer.

8. The method for manufacturing a shielding film according to claim 6, wherein: The method for preparing the cured adhesive layer having the shielding area pattern groove and the buffer area pattern groove connected to the shielding area pattern groove comprises: providing a substrate; Applying a layer of curing glue on the surface of the substrate to form a curing glue layer; A shielding area pattern groove and a buffer area pattern groove connected to the shielding area pattern groove are prepared on the cured adhesive layer.

9. The method for manufacturing a shielding film according to claim 8, characterized in that: The specific steps of preparing the shielding area pattern groove and the buffer area pattern groove connected to the shielding area pattern groove on the cured adhesive layer include: Providing a mold having a grid pattern and a buffer pattern, wherein the grid pattern is connected to the buffer pattern; Imprinting the mold on the cured adhesive layer; After curing, the shielding area pattern groove and the buffer area pattern groove are formed.

10. The method for manufacturing a shielding film according to claim 6, wherein: The width of the metal line in the shielding area is 3-10 μm, and the width of the buffer area is 0.5-2 cm.

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