Cover film structure capable of preventing static damage

Abstract

The utility model discloses a cover film structure capable of preventing static damage, which comprises a cover film structure arranged on a flexible printed circuit (FPC), a copper layer is arranged on the FPC, and a copper exposing area is arranged on the copper layer. The cover film structure comprises a first PI layer, an ITO layer, a second PI layer, an ACF layer and an AD adhesive layer, wherein the first PI layer, the ITO layer and the second PI layer are sequentially arranged from top to bottom; the AD adhesive layer is arranged on the copper layer, and the copper exposed area penetrates through the AD adhesive layer; an ACF layer is arranged in the second PI layer, one end of the ACF layer is in lap joint with the ITO layer, and the other end of the ACF layer sequentially penetrates through the second PI layer and the AD adhesive layer to be in lap joint with the copper exposing area. The ACF layer is used for guiding static electricity accumulated on the ITO layer into the copper exposure area and then connecting the static electricity with GND. According to the utility model, the ITO layer is additionally arranged between the first PI layer and the second PI layer, so that static electricity of the front cover film is accumulated on the ITO layer, the static electricity is prevented from being accumulated to the front circuit, then the static electricity accumulated on the ITO layer is guided into a copper exposed area of the front circuit FPC through the ACF layer and then is connected with GND through the copper layer, the static electricity generated by the front circuit is dissipated, the improvement cost is low, and the use effect is good.

Description

Technical Field

[0001] The utility model relates to a covering film structure, in particular to a covering film structure for preventing electrostatic damage. Background Art

[0002] The common FPC structure is composed of front cover film, front circuit, PI substrate, back circuit, back cover film, and stainless steel sheet, such as Figure 1 As shown, the conventional cover film structure consists of a 12.5um PI substrate 11 and a 15um double-sided tape 12, and has no anti-static capabilities. According to V = 3.9t / d, t = 3.9*ε / CoX, where t is the gate oxide thickness, ε is the dielectric constant of the material, CoX is the gate oxide specific capacitance, and D is the cover film thickness, the above calculation shows that the cover film's electrostatic breakdown voltage is theoretically 1kV, and its anti-static capabilities are very weak. The backside circuit has a stainless steel sheet. When static electricity reaches the surface of the stainless steel sheet, the stainless steel sheet will conduct the static electricity away and prevent it from reaching the surface of the backside circuit. Therefore, even if the backside cover film has weak anti-static capabilities, it will not affect the backside circuit.

[0003] The front circuit is only protected by the front cover film. When static electricity reaches the surface of the front cover film, it will continue to accumulate. When the accumulated static electricity exceeds 1kV, reaching the anti-static voltage of the cover film, the static electricity will break through the cover film and reach the surface of the front circuit, where static electricity will continue to accumulate. Currently, although the anti-static capability can be improved through routing and the inherent performance of the IC, the accumulated static electricity will gradually exceed the tolerance range of the FPC product until the front circuit is broken by static electricity, causing the circuit to break. Therefore, the front circuit is only protected by the front cover film, which makes it prone to the risk of electrostatic damage. Therefore, the existing structure cannot meet the anti-static requirements. Utility Model Content

[0004] The purpose of the utility model is to overcome the deficiencies of the prior art and provide a covering film structure that is anti-static and can effectively prevent static electricity accumulation from causing static electricity damage to the front circuit of the FPC, and the FPC has a strong anti-static ability.

[0005] To achieve the above object, the technical solution adopted by the present invention is: a covering film structure for preventing electrostatic damage, comprising a covering film structure provided on an FPC, the FPC having a copper layer, the copper layer having an exposed copper area;

[0006] The cover film structure includes a first PI layer, an ITO layer, a second PI layer, an ACF layer and an AD adhesive layer; the first PI layer, the ITO layer (and the second PI layer) are arranged in sequence from top to bottom; the AD adhesive layer is arranged on the copper layer, and the copper-exposed area passes through the AD adhesive layer; an ACF layer is provided in the second PI layer, and one end of the ACF layer overlaps the ITO layer, and the other end passes through the second PI layer and the AD adhesive layer in sequence and overlaps the copper-exposed area;

[0007] The ACF layer is used to guide the static electricity accumulated in the ITO layer into the copper exposed area and then connect it to GND to dissipate the static electricity.

[0008] Furthermore, the ACF layer is vertically arranged to the ITO layer and the copper exposed area.

[0009] Furthermore, the ACF layer is anisotropic conductive adhesive.

[0010] Furthermore, the position and size of the ACF layer are adapted to the copper exposed area of ​​the FPC copper layer.

[0011] Furthermore, the thickness of the first PI layer and the second PI layer is 10-12.5 μm.

[0012] Furthermore, the first PI layer and the second PI layer are made of a polyimide flexible substrate.

[0013] Furthermore, the ITO layer is an indium tin oxide coating.

[0014] Furthermore, the thickness of the ITO layer is between 10 nm and 30 nm.

[0015] Furthermore, a window area is provided in the second PI layer, and the position and size of the window area are adapted to the copper exposed area.

[0016] Furthermore, the AD adhesive layer is made of acrylic acid or acrylic.

[0017] Due to the application of the above technical solution, the utility model has the following advantages compared with the prior art:

[0018] The anti-static covering film structure of the utility model adds an ITO layer between the first PI layer and the second PI layer, so that the static electricity on the front covering film accumulates in the ITO layer, preventing the static electricity from accumulating on the front circuit, and the static electricity accumulated on the ITO layer is introduced into the exposed copper area in the front circuit FPC through the ACF layer and then connected to the GND through the copper layer, thereby dissipating the static electricity generated on the front. The utility model has a simple structure, low cost, good use effect, and better meets actual use needs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The technical solution of the utility model is further described below with reference to the accompanying drawings:

[0020] Figure 1 It is a structural schematic diagram of a covering membrane structure in the prior art;

[0021] Figure 2 This is a schematic structural diagram of an embodiment of the present utility model;

[0022] Among them: 1. FPC; 2. Copper layer; 3. First PI layer; 4. ITO layer; 5. Second PI layer; 6. ACF layer; 7. AD adhesive layer; 11. PI substrate; 12. Double-sided tape; 20. Exposed copper area; 50. Window area. DETAILED DESCRIPTION

[0023] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0024] The utility model provides a covering film structure for preventing electrostatic damage, so as to solve the problem in the prior art that the static electricity accumulated in the front circuit will gradually exceed the range that the FPC product can withstand, until the front circuit is broken by static electricity, causing the circuit to be disconnected, which easily leads to the risk of electrostatic damage.

[0025] For ease of understanding, the specific process in the embodiment of this application is described below. Figure 2 In an embodiment of the present application, a covering film structure for preventing electrostatic damage includes a covering film structure provided on an FPC 1, wherein the FPC has a copper layer 2, and the copper layer has an exposed copper area 20; the covering film structure includes a first PI layer 3, an ITO layer 4, a second PI layer 5, an ACF layer 6 and an AD adhesive layer 7; the first PI layer 3, the ITO layer 4 and the second PI layer 5 are arranged in sequence up and down; the AD adhesive layer 7 is arranged on the copper layer 2, and the exposed copper area 20 passes through the AD adhesive layer 7; an ACF layer 6 is provided in the second PI layer 5, and one end of the ACF layer 6 overlaps with the ITO layer 4, and the other end passes through the second PI layer 5 and the AD adhesive layer 7 in sequence and overlaps with the exposed copper area 20; wherein the ACF layer 6 is used to introduce the static electricity accumulated on the ITO layer 4 into the exposed copper area 20 and then dissipate the static electricity by connecting it to GND through the copper layer 2.

[0026] The anti-static covering film structure of the present invention adds an ITO layer 4 on the surface of the covering film for shielding, and at the same time uses the ACF layer 6 to conduct the static electricity accumulated in the ITO layer 4 through the exposed copper area 20 to the GND of the copper layer 2 of the front circuit, and then conducts it to the ground through the GND, thereby achieving the effect of static dissipation, thereby avoiding static electricity from damaging the front circuit and ensuring the normal use of the FPC.

[0027] Furthermore, in this embodiment, the ACF layer 6 is vertically arranged to the ITO layer 4 and the copper exposed area 20 , so that static electricity can be effectively conducted downward and then dissipated.

[0028] Furthermore, the ACF layer 6 is a layer of 25um thick anisotropic conductive adhesive, which can make the ITO layer 4 and the exposed copper area 20 conductive with each other in the vertical direction, so that the excess static electricity accumulated on the surface of the ITO layer 4 can migrate to the exposed copper area 20 of the copper layer 2. The copper thickness of the exposed copper area 20 is 5um. The position and size of the ACF layer 6 depend on the position and size of the exposed copper area 20, that is, depend on the position and size of the FPC window. The two are consistent, so that the ACF layer 6 can conduct static electricity downward to the exposed copper area 20.

[0029] Furthermore, the thickness of the first PI layer 3 and the second PI layer 5 is 10-12.5 μm. Both the first PI layer 3 and the second PI layer 5 are polyimide flexible substrates. The first PI layer 3 primarily serves to support the ITO and protect the cover film. The second PI layer 5 has a window area 50 within it, and the position and size of the window area 50 are adapted to and consistent with the exposed copper area 20. The main function of the window area 50 is to protect the ITO layer 4 and provide a channel for static electricity transmission.

[0030] Furthermore, the ITO layer 4 is an indium tin oxide coating formed on the back of the PIN layer by magnetron sputtering, with a thickness of 10 nm to 30 nm and a square resistance of 100 Ω / □ to 150 Ω / □, and mainly plays an antistatic role.

[0031] Furthermore, the AD adhesive layer 7 is a double-sided adhesive with a thickness of 15um and acrylic acid or acrylic as the main component. Its main function is to stick the second PI layer 5 and the copper layer 2 in the FPC1 together. Its position and size depend on the non-exposed copper area of ​​the copper layer 2 of the FPC1, that is, the position and size of the non-window of the FPC.

[0032] The working process of the present invention is as follows: when static electricity generated by the outside world reaches the surface of the front covering film, static electricity will continue to accumulate on the surface of the front covering film. When the accumulated static electricity exceeds 1KV and reaches the antistatic voltage that the covering film can withstand, the static electricity will break through the covering film and reach the ITO layer 4. Since the ITO layer 4 is overlapped with the ACF layer 6 at the window position 50 of the second PI layer 5, the static electricity accumulated in the ITO layer 4 will continue to migrate to the ACF layer 6, and will not continue to accumulate in the ITO layer 4.

[0033] At the same time, since the ACF layer 6 and the exposed copper area 20 in the copper layer 2 overlap with each other, the static electricity that migrates to the ACF layer 6 will continue to migrate to the exposed copper area 20 in the copper layer 2 of the FPC1. The accumulated static electricity generated in the exposed copper area 20 will be introduced into the ground through the GND of the front line. In this way, a complete static electricity migration route can be formed, and the static electricity accumulated on the front cover film from the outside will be introduced into the ground through the ITO layer 4, ACF layer 6, exposed copper area 20, copper layer 2 and GND layer in sequence, so that the static electricity is completely dissipated, preventing static electricity from accumulating in the front line and causing static electricity damage and disconnection of the line, thereby achieving anti-static protection for the FPC.

[0034] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A covering film structure for preventing electrostatic damage, characterized in that: The invention comprises a covering film structure provided on an FPC (1), wherein the FPC (1) has a copper layer (2), and the copper layer (2) has a copper exposed area (20); The covering film structure comprises a first PI layer (3), an ITO layer (4), a second PI layer (5), an ACF layer (6) and an AD adhesive layer (7); the first PI layer (3), the ITO layer (4) and the second PI layer (5) are arranged in sequence from top to bottom; the AD adhesive layer (7) is arranged on the copper layer (2), and the copper-exposed area (20) passes through the AD adhesive layer (7); an ACF layer (6) is arranged in the second PI layer (5), and one end of the ACF layer (6) overlaps the ITO layer (4), and the other end passes through the second PI layer (5) and the AD adhesive layer (7) in sequence and overlaps the copper-exposed area (20); The ACF layer (6) is used to guide the static electricity accumulated in the ITO layer (4) into the copper exposed area (20) and then dissipate the static electricity by connecting it to GND through the copper layer (2).

2. The anti-static covering film structure according to claim 1, wherein: The ACF layer (6), the ITO layer (4) and the copper-exposed area (20) are arranged vertically.

3. The anti-static covering film structure according to claim 1, wherein: The ACF layer (6) is anisotropic conductive adhesive.

4. The anti-static covering film structure according to claim 1, wherein: The position and size of the ACF layer (6) are adapted to the copper-exposed area (20) of the copper layer (2) in the FPC (1).

5. The anti-static covering film structure according to claim 1, wherein: The thickness of the first PI layer (3) and the second PI layer (5) is 10 to 12.5 μm.

6. The anti-static covering film structure according to claim 1, wherein: The first PI layer (3) and the second PI layer (5) are made of a polyimide flexible substrate.

7. The anti-static covering film structure according to claim 1, wherein: The ITO layer (4) is an indium tin oxide coating.

8. The anti-static covering film structure according to claim 1, wherein: The thickness of the ITO layer (4) is between 10 nm and 30 nm.

9. The anti-static covering film structure according to claim 1, wherein: The second PI layer (5) has a window area (50), and the position and size of the window area (50) are adapted to the copper-exposed area (20).

10. The anti-static covering film structure according to claim 1, wherein: The AD adhesive layer (7) is made of acrylic acid or acrylic.

Images