Flexible circuit board for touch screen

Abstract

The embodiment of the utility model provides a flexible circuit board for a touch screen, which comprises a flexible circuit board main body, and at least one side edge of the flexible circuit board main body is sequentially provided with a pressing position and a bending area from the outer edge to the inside; the grid copper laying layers cover the outer surfaces of the front surface and the back surface of the flexible circuit board main body; the insulating layer covers the outer side surface of the grid copper laying layer; the EMI shielding film covers the outer side surface of the insulating layer; the edges of the sides, close to the press-fit position, of the grid copper laying layer and the EMI shielding film retreat by a first distance and a second distance relative to the inner edge of the press-fit position, the first distance is larger than the second distance, the grid copper laying layer avoids the bending area, and the EMI shielding film partially covers the bending area. According to the embodiment of the utility model, the edge of the grid copper laying layer and the edge of the EMI shielding film are respectively retreated by the first distance and the second distance relative to the inner edge of the pressing position, the grid copper laying layer is enabled to avoid the bending area, and the EMI shielding film partially covers the bending area, so that the thickness of the bending area can be reduced, and the flexibility of the bending area is improved.

Description

TECHNICAL FIELD

[0001] The embodiment of the utility model relates to flexible circuit board technical field, especially touch screen's flexible circuit board. BACKGROUND

[0002] In touch display screen, flexible circuit board (Flexible Printed Circuit, FPC for short) bears the bridge function of transmitting information between touch display module and control mainboard. FPC and control mainboard are generally designed in the shell, so it is necessary to consider the bending performance of flexible circuit board.

[0003] The existing FPC mainly includes flexible insulating film substrate, circuit layer formed on the surface of the substrate layer, grid copper layer covered on the outer side of the circuit layer, insulating layer covered on the outer side of the grid copper layer and EMI shielding film covered on the outer side of the insulating layer.

[0004] However, the inventor found in the specific implementation that the bending area close to the pressing position of the above-mentioned existing FPC has a multilayer structure of EMI shielding film, grid copper layer and insulating layer, which leads to a large thickness of the bending area and poor bending performance, and the pressing position is prone to tearing and malfunction. UTILITY MODEL CONTENT

[0005] The technical problem to be solved by the embodiment of the utility model is to provide a flexible circuit board for touch screen, which can effectively improve the folding performance.

[0006] In order to solve the above technical problems, the embodiment of the utility model provides the following technical scheme: a flexible circuit board for touch screen, comprising:

[0007] A flexible circuit board body, at least one side of the flexible circuit board body is provided with a pressing position and a bending area from the outer edge to the inside in turn;

[0008] A grid copper layer covered on the outer surface of the front and back of the flexible circuit board body;

[0009] An insulating layer covered on the outer side of the grid copper layer; and

[0010] An EMI shielding film covered on the outer side of the insulating layer;

[0011] Wherein, the EMI shielding film and the grid copper layer are respectively retreated by a first distance and a second distance from the side edge adjacent to the pressing position relative to the inner edge of the pressing position, the second distance is greater than the first distance, and the grid copper layer avoids the bending area and the EMI shielding film partially covers the bending area.

[0012] Furthermore, the copper plating layer is a diagonal plating layer, the insulating layer completely covers the copper plating layer, and the edge of the insulating layer near the bonding position is connected to the inner edge of the bonding position.

[0013] Furthermore, the ratio of the line width to the line spacing of the grid lines in the copper plating layer is 1:15.

[0014] Furthermore, the insulating layer is also provided with windows, and the windows respectively opened on the front and back of the insulating layer are staggered with each other.

[0015] Furthermore, the opening is a circular hole with a diameter of 2mm.

[0016] Furthermore, the flexible circuit board body includes a flexible insulating film and circuit layers formed on the front and back surfaces of the flexible insulating film. The flexible circuit board body has a plurality of vias connected to the circuit layers on both sides at a predetermined position away from the pressing position, and the vias are staggered with each other.

[0017] Furthermore, the distance between the bending area and the inner edge of the pressing position is 3mm, the first distance is 12.6mm, and the second distance is 5.8mm.

[0018] After adopting the above technical solution, the present utility model embodiment has at least the following beneficial effects: The present utility model embodiment, by moving the edges of the mesh copper layer and the EMI shielding film back by a first distance D1 and a second distance D2 respectively relative to the inner edge of the lamination position, and the first distance D1 is greater than the second distance D2, also makes the mesh copper layer avoid the bending area while the EMI shielding film partially covers the bending area, thereby effectively reducing the thickness of the bending area, which is beneficial to improving the bending performance of the bending area and ensuring good EMI performance. Attached Figure Description

[0019] Figure 1 This is a top view of an optional embodiment of the flexible circuit board for touch screens according to the present invention.

[0020] Figure 2 This is a side view of an optional embodiment of the flexible circuit board for touch screens according to the present invention.

[0021] Figure 3 for Figure 1 A magnified schematic diagram of a portion of the structure in section A.

[0022] Figure 4 for Figure 1 A magnified schematic diagram of a portion of the structure in section B. Detailed Implementation

[0023] The application will be described in further detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following illustrative embodiments and descriptions are only intended to explain the application and are not intended to limit the application, and the embodiments in the application and the features in the embodiments can be combined with each other without conflict.

[0024] As shown in Figures 1-2 An optional embodiment of the application provides a flexible circuit board for a touch screen, comprising:

[0025] A flexible circuit board body 1, at least one side edge of the flexible circuit board body 1 is provided with a press-fit position 10 and a bending area 12 in sequence from outside to inside;

[0026] A grid copper layer 3 covering the front and back outer surfaces of the flexible circuit board body 1;

[0027] An insulating layer 5 covering the outer side of the grid copper layer 3; and

[0028] An EMI shielding film 7 covering the outer side of the insulating layer 5;

[0029] Wherein, the grid copper layer 3 and the EMI shielding film 5 are both retreated from the inner edge of the press-fit position 10 by a first distance D1 and a second distance D2 respectively, the first distance D1 is greater than the second distance D2, and the grid copper layer 3 avoids the bending area 12 while the EMI shielding film 7 partially covers the bending area 12.

[0030] The embodiment retreats the edges of the grid copper layer 3 and the EMI shielding film 7 from the inner edge of the press-fit position 10 by a first distance D1 and a second distance D2 respectively, the first distance D1 is greater than the second distance D2, and the grid copper layer 3 avoids the bending area 12 while the EMI shielding film 7 partially covers the bending area 12, so that the thickness of the bending area 12 can be effectively reduced, the bending performance of the bending area 12 is improved, and the EMI performance is ensured to be good.

[0031] In an optional embodiment of the application, as shown in Figures 1 to 4 The grid copper layer 3 is a diagonal grid, the insulating layer 5 completely covers the grid copper layer 3, and the edge of the insulating layer 5 close to the press-fit position 10 is connected with the inner edge of the press-fit position 10. The embodiment designs the grid copper layer 3 as a diagonal grid to improve the bending performance, and the insulating layer 5 completely covers the grid copper layer 3, and the edge of the insulating layer 5 close to the press-fit position 10 is connected with the inner edge of the press-fit position 10, so that the grid copper layer 3 and the flexible circuit board body 1 on the inner side can be better protected.

[0032] In an optional embodiment of the utility model, the ratio of the line width and the line distance of the grid line in the grid copper layer 3 is 1:15. This embodiment defines a relatively preferred ratio of the line width and the line distance of the grid line, which can greatly improve the softness of the FPC while ensuring the shielding effect of the grid copper layer. Preferably, the line width can be designed as 0.1mm, and the line distance is designed as 1.5mm.

[0033] In an optional embodiment of the utility model, as shown in Figure 1 and Figure 3 , the insulating layer 5 is further provided with a window 50, and the windows 50 on the front and back surfaces of the insulating layer 5 are arranged in a staggered manner. In a preferred embodiment of the utility model, the window 50 is a circular hole with a diameter of 2mm. This embodiment sets the window 50, and the windows 50 on the front and back surfaces are arranged in a staggered manner, and the number is evenly distributed according to the actual wiring. The upper and lower layers are arranged in a staggered manner, which can ensure that the EMI shielding film 7 around and in the center can be grounded and shielded. It not only meets the EMI shielding grounding performance, but also optimizes the softness of the FPC. By preferably setting the window 50 as a circular hole and limiting its diameter, the FPC production process capacity can be met, and the bending stress is small.

[0034] In an optional embodiment of the utility model, as shown in Figure 1 , Figure 2 and Figure 4 , the flexible circuit board body 1 includes a flexible insulating film 14 and a circuit layer 16 formed on the front and back surfaces of the flexible insulating film 14. A plurality of through holes 18 are provided in the predetermined position away from the pressing position 10 to communicate the circuit layers 16 on the two surfaces, and the through holes 18 are arranged in a staggered manner. This embodiment communicates the circuit layers 16 on the two surfaces by arranging the through holes 18 in a staggered manner at the predetermined position away from the pressing position 10, which can avoid the pressing and bending of the through hole, and form a functional defect.

[0035] In an optional embodiment of the utility model, as shown in Figure 2 , the distance between the bending area 12 and the inner edge of the pressing position 10 is 3mm, the first distance D1 is 12.6mm, and the second distance D2 is 5.8mm. This embodiment can well control the position of each structure layer by setting specific distance values, so as to well balance the bending performance and EMI shielding effect of the bending area 12. It should be noted that, in order to clearly show the mutual position relationship of each layer structure, Figure 2 the related dimensions are enlarged in a non-proportional manner, Figure 2 the dashed line in the figure is only used to distinguish the pressing area 10 and the bending area 12, and is not an actual structure line.

[0036] The embodiments of the present application are described above with reference to the drawings; however, the present application is not limited to the specific embodiments described above, but the specific embodiments described above are merely illustrative rather than restrictive, and a person of ordinary skill in the art can make many forms under the inspiration of the present application without departing from the purpose of the present application and the scope protected by the claims, and these all belong to the protection scope of the present application.

Claims

1. A flexible circuit board for a touch screen, comprising: a flexible circuit board body, at least one side edge of the flexible circuit board body being provided with a press-fit site and a bending area in sequence inwardly from an outer edge; a grid copper layer covering outer surfaces of front and back surfaces of the flexible circuit board body; an insulating layer covering outer surfaces of the grid copper layer; an EMI shielding film covering outer surfaces of the insulating layer; characterized in that the grid copper layer and the EMI shielding film are respectively retreated by a first distance and a second distance from an inner edge of the press-fit site relative to a side edge of the press-fit site, the first distance being greater than the second distance, and the grid copper layer avoids the bending area while the EMI shielding film partially covers the bending area. The grid copper layer is a diagonal grid, the insulating layer completely covers the grid copper layer, and the insulating layer is connected to the inner edge of the press-fit site relative to a side edge of the press-fit site.

2. The flexible circuit board for a touch screen according to claim 1, wherein, A ratio of line width to line spacing of the grid lines in the grid copper layer is 1:

15.

3. The flexible circuit board for a touch screen according to claim 1 or 2, wherein The insulating layer is further provided with windows, and the windows on the front and back surfaces of the insulating layer are arranged in a staggered manner.

4. The flexible circuit board for a touch screen according to claim 1, wherein, The windows are circular holes with a diameter of 2mm.

5. The flexible circuit board for a touch screen according to claim 4, wherein, The flexible circuit board body comprises a flexible insulating film and a circuit layer formed on both side surfaces of the flexible insulating film, and a plurality of through holes are provided in the flexible circuit board body at predetermined positions away from the press-fit site to connect the circuit layers on both side surfaces, and the through holes are arranged in a staggered manner.

6. The flexible circuit board for a touch screen according to claim 1, 2, 4 or 5, wherein, The distance between the bending area and the inner edge of the press-fit site is 3mm, the first distance is 12.6mm, and the second distance is 5.8mm.

7. The flexible circuit board for a touch screen according to claim 1, wherein, The flexible circuit board body comprises a flexible insulating film and a circuit layer formed on both side surfaces of the flexible insulating film, and a plurality of through holes are provided in the flexible circuit board body at predetermined positions away from the press-fit site to connect the circuit layers on both side surfaces, and the through holes are arranged in a staggered manner.

8. The flexible circuit board for a touch screen according to claim 3, wherein, ​

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