Fixing structure of flexible circuit board

Abstract

The invention discloses a fixing structure of a flexible circuit board, which comprises a backlight rear iron frame and an FPC body, the bending section of the FPC body is provided with silk-screen green oil, the back surface of the FPC body is provided with a pasting assembly, and the pasting assembly comprises a strong-viscosity double-sided adhesive, a conductive double-sided adhesive and a release film; the backlight rear iron frame is provided with a guide column, and a positioning through hole is formed in the position, corresponding to the guide column, of the FPC body. According to the backlight structure, the screen printing green oil is used for replacing a covering film PI layer on the bending section of the FPC body, so that the bending position is softer and not prone to bounce, the better effect of preventing the FPC body from being disengaged is achieved, and the service life of the FPC body is prolonged. And meanwhile, the spliced high-viscosity double-sided adhesive and the conductive double-sided adhesive are additionally adhered to the backlight rear iron frame, so that the adhesion between the FPC body and the backlight rear iron frame is enhanced, finally, the effects of fixing the FPC body and preventing separation are achieved, and the overall reliability is improved.

Description

Technical Field

[0001] The invention relates to the technical field of flexible circuit boards, and in particular to a fixing structure of a flexible circuit board. Background Art

[0002] Flexible printed circuit board (FPC for short) is a highly reliable and extremely flexible printed circuit board made of polyimide or polyester film as the base material.

[0003] As market competition becomes increasingly fierce, customers have higher and higher requirements for the reliability of display modules, especially in the military, automotive and medical industries. This requires better design solutions for the display module structure to ensure the reliability of the module in order to occupy the high-end market.

[0004] The conventional shipment of LCD screens is to bend the FPC and stick it to the backlight rear iron frame. For FPCs with fewer component areas, the corresponding FPCs will be designed to be smaller in order to save costs. When the FPC is bent and pasted to the backlight rear iron frame, the pasting area of ​​the FPC will also be small. The bending section of the FPC often uses a cover film PI layer, and the thickness of the cover film PI layer is generally 12.5um. It is not soft enough when bent and is prone to rebound. At the same time, the bottom layer of the FPC is generally equipped with a GND leakage copper block to guide the electrostatic interference signal into the rear iron frame. It needs to be adhered to the rear iron frame with conductive double-sided tape. The viscosity of the conductive double-sided tape is generally half of that of ordinary double-sided tape, which can easily cause the FPC to come off and warp, thereby affecting the overall reliability of the LCD screen.

[0005] Therefore, in view of some technical defects in the existing technology when bending FPC and pasting FPC, we specifically designed a fixing structure for the flexible circuit board. Summary of the invention

[0006] In order to overcome the above-mentioned shortcomings, the present invention aims to provide a technical solution that can solve the above-mentioned problems.

[0007] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a fixing structure of a flexible circuit board, comprising a backlight rear iron frame and an FPC body, the bending section of the FPC body is provided with silk-screen green oil, the back of the FPC body is provided with an adhesive component, the adhesive component includes a strong adhesive double-sided adhesive, a conductive double-sided adhesive and a release film; the backlight rear iron frame is provided with a guide column, and a positioning through hole is opened on the FPC body and at a position corresponding to the guide column.

[0008] As a further solution of the present invention: the thickness of the silk-screen green oil is between 9um and 11um.

[0009] As a further solution of the present invention: a GND copper leakage block is arranged at a corner of the back side of the FPC body, and the positioning through holes are opened below the GND copper leakage block and away from each other.

[0010] As a further solution of the present invention: one of the adhesive surfaces of the strong adhesive double-sided adhesive and the conductive double-sided adhesive is respectively adhered to the left and right sides of the release film, and the other adhesive surfaces of the strong adhesive double-sided adhesive and the conductive double-sided adhesive are respectively adhered to the backlight rear iron frame.

[0011] As a further solution of the present invention: the sticking position of the strong adhesive double-sided adhesive on the FPC body is located away from the GND copper leakage block, and the sticking position of the conductive double-sided adhesive on the FPC body is on the GND copper leakage block.

[0012] As a further solution of the present invention: the thickness of the strong adhesive double-sided adhesive and the conductive double-sided adhesive is 0.05 mm, and the edges of the strong adhesive double-sided adhesive and the conductive double-sided adhesive are far away from the edge of the FPC body.

[0013] As a further solution of the present invention: a component area is provided on the side of the FPC body away from the adhesive assembly, and the component area is used to install various components, and the height of the components is higher than the height of the guide column.

[0014] As a further solution of the present invention: at least one guide post and at least one positioning through hole are provided, the diameter of the guide post is 1.4 mm, and the height of the guide post is 3.0 mm.

[0015] As a further solution of the present invention: the guide column has a conical structure with a small upper end and a large lower end, and the diameter of the guide column is smaller than the diameter of the positioning through hole. When the guide column is inserted into the positioning through hole, there is a gap between the two, and hot melt adhesive is provided at the gap between the guide column and the positioning through hole.

[0016] As a further solution of the present invention: after the FPC body is bound to one side of the backlight rear iron frame, the FPC body is bent to the other side of the backlight rear iron frame through the silk-screen green oil on the bending section, and is fixed to the backlight rear iron frame through an adhesive component.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] In the application, by using silk-screen green oil instead of the covering film PI layer in the bending section of the FPC body, the thickness of the green oil can be controlled at about 10um, making the bending position softer and less likely to rebound, which plays a better role in preventing the FPC body from detaching. At the same time, a spliced ​​strong-viscosity double-sided adhesive and a conductive double-sided adhesive are affixed to the iron frame behind the backlight. The conductive double-sided adhesive is adhered to the GND leakage copper block on the back of the FPC body to export the ESD electromagnetic interference signal, while the strong-viscosity double-sided adhesive is adhered to the non-leakage copper block area of ​​the FPC body to strengthen the adhesion between the FPC body and the iron frame behind the backlight, ultimately fixing the FPC body and preventing detachment, thereby improving overall reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a side view structural diagram of the backlight rear iron frame and the FPC body of the present invention;

[0020] Figure 2 It is a front view structural diagram of the backlight rear iron frame and the FPC body of the present invention;

[0021] Figure 3 It is a front cross-sectional structural schematic diagram of the FPC body of the present invention;

[0022] Figure 4 It is a front view structural schematic diagram of the pasting assembly of the present invention;

[0023] Figure 5 This is a schematic diagram of the front view structure of the silk screen green oil at the bending section of the FPC body of the present invention;

[0024] Figure 6 It is a side view structural schematic diagram of the silk-screen green oil of the present invention.

[0025] The reference numerals and names in the figures are as follows:

[0026] 1. Iron frame behind backlight; 2. FPC body; 201, component area; 3. Silk-screen green oil; 4. Positioning through hole; 5. Guide column; 6. GND leakage copper block; 7. Strong adhesive double-sided adhesive; 8. Conductive double-sided adhesive; 9. Release film. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions 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 of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] See also Figure 1-6A fixing structure of a flexible circuit board comprises a backlight rear iron frame 1 and an FPC body 2, a silk screen green oil 3 is arranged on the bending section of the FPC body 2, the thickness of the silk screen green oil 3 is between 9um and 11um, preferably about 10um, a pasting component is arranged on the back of the FPC body 2, and the pasting component comprises a strong adhesive double-sided adhesive 7, a conductive double-sided adhesive 8 and a release film 9; a guide column 5 is arranged on the backlight rear iron frame 1, and a positioning through hole 4 is opened on the FPC body 2 and at a position corresponding to the guide column 5, after the FPC body 2 is bound to one side of the backlight rear iron frame 1, the FPC body 2 is bent to the other side of the backlight rear iron frame 1 through the silk screen green oil 3 on the bending section, and is fixed to the backlight rear iron frame 1 through the pasting component.

[0029] See also Figure 2-3 In this embodiment, a GND copper leakage block 6 is provided at a corner of the back side of the FPC body 2, and the opening position of the positioning through hole 4 is located below the GND copper leakage block 6 and away from each other.

[0030] Specifically, the positioning through hole 4 is opened far away from the GND leakage copper block 6, which can effectively prevent the positioning through hole 4 from affecting the normal operation of the GND leakage copper block 6.

[0031] See also Figure 2-4 In the present embodiment, one of the adhesive surfaces of the strong adhesive double-sided adhesive 7 and the conductive double-sided adhesive 8 is respectively adhered to the left and right sides of the release film 9, and the other adhesive surfaces of the strong adhesive double-sided adhesive 7 and the conductive double-sided adhesive 8 are respectively adhered to the backlight rear iron frame 1; the adhesive position of the strong adhesive double-sided adhesive 7 on the FPC body 2 is located away from the GND copper leakage block 6, and the adhesive position of the conductive double-sided adhesive 8 on the FPC body 2 is located on the GND copper leakage block 6.

[0032] Specifically, when the strong adhesive double-sided adhesive 7 and the conductive double-sided adhesive 8 are not pasted, one side has a release film 9, and the other side has a carrier film, which is used to simultaneously support the strong adhesive double-sided adhesive 7 and the conductive double-sided adhesive 8, so as to facilitate the subsequent pasting together. At the same time, the strong adhesive double-sided adhesive 7 can effectively improve the bonding strength and the firmness of the FPC body 2, while the conductive double-sided adhesive 8 can export the ESD electromagnetic interference signal.

[0033] See also Figure 3-4 In this embodiment, the thickness of the strong adhesive double-sided adhesive 7 and the conductive double-sided adhesive 8 are both 0.05 mm, and the edges of the strong adhesive double-sided adhesive 7 and the conductive double-sided adhesive 8 are both far away from the edge of the FPC body 2.

[0034] Specifically, by controlling the thickness of the strong adhesive double-sided adhesive 7 and the conductive double-sided adhesive 8, it is possible to prevent the FPC body 2 from being too protruding after pasting, which can facilitate the installation of the FPC body 2 and the subsequent installation of components. At the same time, the edges of the strong adhesive double-sided adhesive 7 and the conductive double-sided adhesive 8 are away from the edges of the FPC body 2, leaving sufficient pasting area for the strong adhesive double-sided adhesive 7 and the conductive double-sided adhesive 8 to avoid the possibility of glue overflowing from the edge of the FPC body 2 after pasting.

[0035] See also Figure 2-3 In this embodiment, a component area 201 is provided on the side of the FPC body 2 away from the pasting component, and each component is installed on the component area 201, and the height of the component is higher than the height of the guide column 5; at least one guide column 5 and one positioning through hole 4 are provided, the diameter of the guide column 5 is 1.4 mm, and the height of the guide column 5 is 3.0 mm; the guide column 5 is a conical structure with a small upper end and a large lower end, and the diameter of the guide column 5 is smaller than the diameter of the positioning through hole 4. When the guide column 5 is inserted into the positioning through hole 4, there is a gap between the two, and hot melt adhesive is provided at the gap between the guide column 5 and the positioning through hole 4.

[0036] Specifically, the height of the guide column 5 is lower than the height of the component in the component area 201 to prevent the guide column 5 from being too high and affecting the installation of the component. When the FPC body 2 is bent, it can be inserted into the guide column 5 through the positioning hole 4, which can also achieve a good positioning effect. Applying hot melt glue at the gap between the guide column 5 and the positioning hole 4 of the FPC body 2 can reinforce the FPC body 2 and prevent the FPC body 2 from detaching.

[0037] When pasting the FPC body 2, the strong adhesive double-sided adhesive 7 and the conductive double-sided adhesive 8 are pasted on the alignment line on the backlight rear iron frame 1, the release film 9 is torn off, the FPC body 2 is bent from the silk-screen green oil 3, and the FPC body 2 is bent to the back of the backlight rear iron frame 1, and the guide column 5 enters the positioning through hole 4. The FPC body 2 is pasted with the strong adhesive double-sided adhesive 7 and the conductive double-sided adhesive 8, and the conductive double-sided adhesive 8 is pasted on the GND leakage copper block 6 on the back of the FPC body 2, and the strong adhesive double-sided adhesive 7 is pasted on the non-leakage copper block area of ​​the FPC body 2.

[0038] It should be noted that:

[0039] The bending section of the FPC body 2 uses silk screen green oil 3 to replace the cover film PI layer. The thickness of the cover film PI layer is generally 12.5um, while the thickness of the green oil can be controlled at about 10um, making the bending position softer and less likely to rebound, which plays a certain role in preventing the FPC body 2 from being detached. In order to prevent the silk screen green oil 3 from being unevenly printed on the metal fingertips and easily entering the binding position of the FPC body 2, resulting in hidden dangers such as uneven binding pressure of the FPC body 2, a PI (preferably 1.0mm in width) can be added to the binding position and the bending green oil area. The silk screen green oil 3 covers the PI layer by 0.3mm, and the lower end also covers the PI layer by 0.3mm to avoid the line being exposed and short circuits. Figure 5 and Figure 6 As shown;

[0040] A spliced ​​strong-viscosity double-sided adhesive 7 and a conductive double-sided adhesive 8 are attached to the back iron frame 1 of the back light. The conductive double-sided adhesive 8 is attached to the GND leakage copper block 6 on the back of the FPC body 2 to export the ESD electromagnetic interference signal. The strong-viscosity double-sided adhesive 7 is attached to the non-leakage copper block area of ​​the FPC body 2 to strengthen the adhesion between the FPC body 2 and the back iron frame 1 of the back light. The viscosity of the general conductive double-sided adhesive is only half of that of the strong-viscosity double-sided adhesive 7. The strong-viscosity double-sided adhesive 7 can play a role in fixing the FPC body 2 to prevent it from being disengaged, thereby improving the overall reliability.

[0041] The strong adhesive double-sided adhesive 7 and the conductive double-sided adhesive 8 are spliced ​​on a carrier film, and share a release film 9. A tearing handle is provided on the release film 9. When pasting, the carrier film is torn off and the alignment line on the backlight rear iron frame 1 is pasted. The splicing method can effectively save raw materials and manual operation time. The release film 9 can be torn off through the tearing handle on the release film 9, and the FPC body 2 is pasted on the backlight rear iron frame 1;

[0042] At least one guide post 5 with a diameter of 1.4 mm is provided on the backlight rear iron frame 1. The guide post 5 is arranged near the conductive double-sided adhesive 8. The height of the guide post 5 is generally 3.0 mm, and it is optimal not to exceed the height of the highest component. The guide post 5 is designed to be conical, with a small upper end and a large lower end. A positioning through hole 4 is provided on the FPC body 2 corresponding to the guide post 5. When the FPC body 2 is bent, it is inserted into the guide post 5 through the positioning through hole 4. Hot melt adhesive is applied to the gap between the guide post 5 and the positioning through hole 4 of the FPC body 2 to further fix the FPC body 2 and prevent the FPC body 2 from detaching.

[0043] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A fixing structure of a flexible circuit board, characterized in that: It includes a backlight rear iron frame (1) and an FPC body (2). A silk-screen green ink (3) is provided on the bending section of the FPC body (2), and an adhesive component is provided on the back of the FPC body (2), wherein the adhesive component comprises a strong adhesive double-sided adhesive (7), a conductive double-sided adhesive (8) and a release film (9); The backlight rear iron frame (1) is provided with a guide column (5), and a positioning through hole (4) is provided on the FPC body (2) at a position corresponding to the guide column (5).

2. A fixing structure for a flexible circuit board according to claim 1, characterized in that: The thickness of the silk-screen green ink (3) is between 9um and 11um.

3. The fixing structure of a flexible circuit board according to claim 1, characterized in that: A GND copper leakage block (6) is provided at a corner of the back side of the FPC body (2), and the opening positions of the positioning through holes (4) are located below the GND copper leakage block (6) and are far away from each other.

4. The fixing structure of a flexible circuit board according to claim 1, characterized in that: One of the adhesive surfaces of the strong adhesive double-sided adhesive (7) and the conductive double-sided adhesive (8) is respectively adhered to the left and right sides of the release film (9), and the other adhesive surfaces of the strong adhesive double-sided adhesive (7) and the conductive double-sided adhesive (8) is respectively adhered to the backlight rear iron frame (1).

5. A fixing structure for a flexible circuit board according to claim 4, characterized in that: The strong adhesive double-sided adhesive (7) is located at a position away from the GND copper leakage block (6) at the adhesive position of the FPC body (2), and the conductive double-sided adhesive (8) is located on the GND copper leakage block (6) at the adhesive position of the FPC body (2).

6. The fixing structure of a flexible circuit board according to claim 1, characterized in that: The thickness of the strong adhesive double-sided adhesive (7) and the conductive double-sided adhesive (8) are both 0.05 mm, and the edges of the strong adhesive double-sided adhesive (7) and the conductive double-sided adhesive (8) are both far away from the edge of the FPC body (2).

7. The fixing structure of a flexible printed circuit board according to claim 1, characterized in that: A component area (201) is provided on the side of the FPC body (2) away from the adhesive component. The component area (201) is used to install various components, and the height of the components is higher than the height of the guide column (5).

8. The fixing structure of a flexible circuit board according to claim 1, characterized in that: The guide column (5) and the positioning through hole (4) are each provided with at least one, the diameter of the guide column (5) is 1.4 mm, and the height of the guide column (5) is 3.0 mm.

9. A fixing structure for a flexible printed circuit board according to claim 8, characterized in that: The guide column (5) is in a conical structure with a small upper end and a large lower end. The diameter of the guide column (5) is smaller than the diameter of the positioning through hole (4). When the guide column (5) is inserted into the positioning through hole (4), a gap exists between the two. Hot melt adhesive is provided at the gap between the guide column (5) and the positioning through hole (4).

10. The fixing structure of a flexible circuit board according to claim 1, characterized in that: After the FPC body (2) is bound to one side of the backlight rear iron frame (1), the FPC body (2) is bent to the other side of the backlight rear iron frame (1) by means of the silk-screen green oil (3) on the bending section, and is fixed to the backlight rear iron frame (1) by means of an adhesive assembly.

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