Flexible Printed Circuit Board, Display Module and Display Device

Abstract

The present disclosure relates to a flexible printed circuit board, which includes a first region extending in a first direction. Along the first direction, the first region includes an adjacent bonding region and a routing region. Along a second direction, at least one side of the bonding region is provided with a conductive functional region, and the conductive functional region is electrically connected to a ground wire in the routing region for grounding, and the second direction is set at an angle to the first direction; the flexible printed circuit board includes a base layer, and the conductive functional region includes two conductive layers located on opposite sides of the base layer, and the two conductive layers are electrically connected through vias. The present disclosure also relates to a display module and a display device.

Description

Technical Field

[0001] The present disclosure relates to the technical field of display product manufacturing, and particularly to a flexible printed circuit board, a display module, and a display device. Background Art

[0002] In On-cell type rigid wearable OLED products, some end customers require that the TP (touch) functional component has a grounded design. The conventional grounding route of the design scheme: TFPC GND trace → TFPC exposed copper → conductive adhesive → SCF / NFC → MFPC (main flexible printed circuit board) → the main board of the whole machine → metal middle frame / metal back cover, or TFPC GND trace → MFPC → the main board of the whole machine → metal middle frame / metal back cover.

[0003] For the former grounding route, the end point of the grounding route is generally the metal middle frame / metal back cover, and the grounding efficiency and the anti-ESD (electrostatic discharge) ability are relatively low; the latter grounding route requires that the GND line needs to be added to the trace at the position of the connector (Connector / ZIF) of TFPC and MFPC, which generally means that a larger connector needs to be used, which is disadvantageous both in terms of cost and space occupation. Summary of the Invention

[0004] In order to solve the above technical problems, the present disclosure provides a flexible printed circuit board, a display module, and a display device, which solve the problem of low grounding efficiency of the flexible printed circuit board.

[0005] To achieve the above object, the technical solution adopted in the embodiment of the present disclosure is: a flexible printed circuit board, including a first region extending along a first direction. Along the first direction, the first region includes an adjacent bonding region and a routing region. Along a second direction, at least one side of the bonding region is provided with a conductive functional region, and the conductive functional region is electrically connected to a ground wire in the routing region for grounding, and the second direction is set at an angle to the first direction;

[0006] The flexible printed circuit board includes a base layer, and the conductive functional region includes two conductive layers located on opposite sides of the base layer, and the two conductive layers are electrically connected through vias.

[0007] Optionally, the bonding region includes signal connection pins and ground pins located on at least one side of the signal connection pins along the first direction, the routing region includes signal traces connected to the signal connection pins and the ground wires located on at least one side of the signal traces along the first direction, and the ground wires and the corresponding conductive functional regions are located on the same side of the first region.

[0008] Optionally, it includes a base layer, a first conductive layer located in the first region, a second conductive layer and a third conductive layer located in the conductive functional region;

[0009] The first conductive layer is located on the first side of the base layer and includes the signal trace, the signal connection pin, the ground wire and the ground pin;

[0010] The second conductive layer is located on the first side of the base layer, and the second conductive layer is electrically connected to the ground pin;

[0011] The third conductive layer is located on the second side of the base layer opposite to the first side, and the third conductive layer is electrically connected to the second conductive layer through a via hole penetrating the base layer.

[0012] Optionally, the orthographic projection of the third conductive layer on the base layer at least partially overlaps with the orthographic projection of the second conductive layer on the base layer.

[0013] Optionally, an insulating protective layer is provided on the side of the base layer away from the first conductive layer.

[0014] Optionally, the first region and the conductive functional region are integrally connected to form a T-shaped structure. Along the first direction, the base layer includes a first side edge away from the trace region. Along the first direction, the conductive functional region includes a second side edge on the same side as the first side edge, and the first side edge and the second side edge are flush.

[0015] Optionally, in the base layer, along the first direction, the bonding region includes a plurality of signal connection pins arranged at intervals, and the ground pin and the adjacent signal connection pin are arranged at intervals.

[0016] The embodiment of the present disclosure further provides a display module, including a display panel, a cover plate and the above flexible circuit board disposed between the display panel and the cover plate;

[0017] The flexible circuit board is bonded and connected to the display panel, a fourth conductive layer is provided at the edge of the cover plate, and the conductive functional region of the flexible circuit board is electrically connected to the fourth conductive layer.

[0018] Optionally, the cover plate includes a first surface facing the display panel, a second surface away from the display panel, and a first side surface located between the first surface and the second surface. The first side surface is close to the flexible circuit board. The fourth conductive layer includes a first sub-conductive layer provided at the edge of the first surface close to the first side surface, a second sub-conductive layer provided on the first side surface, and a third sub-conductive layer provided at the edge of the second surface close to the first side surface;

[0019] The first sub-conductive layer, the second sub-conductive layer, and the third sub-conductive layer enclose a U-shaped structure.

[0020] Optionally, the cover plate includes a light-transmitting area corresponding to the display area of the display panel and a light-shielding area located outside the light-transmitting area. The orthographic projection of the first sub-conductive layer on the cover plate is located within the light-shielding area, and the orthographic projection of the third sub-conductive layer on the cover plate is located within the light-shielding area.

[0021] Optionally, the flexible printed circuit board and the cover plate are connected by a conductive foam adhesive.

[0022] Optionally, in the direction perpendicular to the cover plate, the height of the conductive foam adhesive is 0.3 - 0.4 mm.

[0023] Optionally, the orthographic projection of the conductive functional area of the flexible printed circuit board on the cover plate is located within the orthographic projection of the conductive foam adhesive on the cover plate.

[0024] Optionally, the display panel includes a display substrate and a touch control substrate located on the light-emitting side of the display substrate, and the flexible printed circuit board is bonded to the touch control substrate.

[0025] An embodiment of the present disclosure further provides a display device, including the above-mentioned display module.

[0026] The beneficial effect of the present disclosure is that through the setting of the conductive functional area, the grounding line is guided to the cover plate, without increasing the volume of the connector between the flexible printed circuit board and the main flexible printed circuit board, shortening the grounding path, and improving the grounding efficiency. Description of the Drawings

[0027] Figure 1 Schematic diagram of the structure of the flexible printed circuit board in the embodiment of the present disclosure Figure 1 ;

[0028] Figure 2 Schematic diagram of the structure of the flexible printed circuit board in the embodiment of the present disclosure Figure 2 ;

[0029] Figure 3 Schematic diagram of the structure of the display module in the embodiment of the present disclosure Figure 1 ;

[0030] Figure 4 Schematic diagram of the structure of the display module in the embodiment of the present disclosure Figure 2 . Detailed Embodiments

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present disclosure. Apparently, the described embodiments are only a part rather than all of the embodiments of the present disclosure. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present disclosure fall within the scope of protection of the present disclosure.

[0032] In the description of the present disclosure, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. These are only for the convenience of describing the present disclosure and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present disclosure. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and should not be construed as indicating or implying relative importance.

[0033] Referring to Figures 1 - 4 , this embodiment provides a flexible printed circuit board 10, including a first area 1 extending in a first direction. Along the first direction (referring to the X direction in Figure 1 ), the first area 1 includes an adjacent bonding area 11 and a routing area. Along a second direction (referring to the Y direction in Figure 1 ), at least one side of the bonding area 11 is provided with a conductive functional area 2. The conductive functional area 2 is electrically connected to a ground wire 16 in the routing area for grounding. The second direction is set at an angle to the first direction; the flexible printed circuit board includes a base layer. The conductive functional area includes two conductive layers located on opposite sides of the base layer, and the two conductive layers are electrically connected through vias.

[0034] In the related art, the grounding circuits of the flexible printed circuit board 10 generally include the following two types: TFPC GND trace → TFPC exposed copper → conductive adhesive → SCF / NFC → MFPC → main board of the whole machine → metal middle frame / metal back cover, or TFPC GND trace → MFPC → main board of the whole machine → metal middle frame / metal back cover. In either case, the grounding path is relatively long. And in the latter grounding circuit, it is required to add a GND line to the routing of the connectors (Connector / ZIF) of the TFPC and the MFPC, which generally means using larger connectors. In this embodiment, through the setting of the conductive functional area 2, the grounding circuit is directly guided to the cover plate 4, shortening the grounding path, improving the grounding efficiency, and without increasing the volume of the connector between the flexible printed circuit board 10 and the main flexible printed circuit board, thus reducing the cost.

[0035] In an exemplary embodiment, the bonding region 11 includes signal connection pins 13 and ground pins 14 located on at least one side of the signal connection pins 13 along the first direction. The trace region includes signal traces 15 connected to the signal connection pins 13 and the ground lines 16 located on at least one side of the signal traces 15 along the first direction. The ground lines 16 and the corresponding conductive functional regions 2 are on the same side of the first region 1.

[0036] The extending direction of the signal traces 15 is parallel to the first direction, and the extending direction of the ground lines 16 is parallel to the first direction. In the second direction, the conductive functional regions 2 are located on at least one side of the bonding region 11, and the ground pins 14 are located on one side of the signal connection pins 13, that is, the ground pins 14 can be directly connected to the conductive functional regions 2, which is convenient for the distribution of circuits and simplifies the structural arrangement.

[0037] In an exemplary embodiment, the bonding region 11 includes a plurality of the signal connection pins 13, and the plurality of signal connection pins 13 are arranged at intervals along the second direction. And in one embodiment, the plurality of signal connection pins 13 are arranged at equal intervals, but this is not limiting.

[0038] In an exemplary embodiment, the distance between the ground pin 14 and the adjacent signal connection pin 13 is equal to the distance between any two adjacent signal connection pins 13, but this is not limiting.

[0039] In an exemplary embodiment, it includes a base layer 12, a first conductive layer 101 located in the first region 1, a second conductive layer 201 and a third conductive layer 202 located in the conductive functional region 2;

[0040] The first conductive layer 101 of the base layer is located on the first side of the base layer 12 and includes the signal traces 15, the signal connection pins 13, the ground lines 16 and the ground pins 14;

[0041] The second conductive layer 201 of the base layer 12 is located on the first side of the base layer 12. The second conductive layer 201 is arranged on the same layer as the first conductive layer 101, and the second conductive layer 201 is electrically connected to the ground pins 14;

[0042] The third conductive layer 202 is located on the second side of the base layer 12 opposite to the first side. The third conductive layer 202 is electrically connected to the second conductive layer 201 through vias 3 penetrating through the base layer 12.

[0043] The base layer 12 can be made of PI (polyimide) material, but this is not limiting.

[0044] The first conductive layer 101 is made of copper material, but is not limited thereto.

[0045] The conductive functional area 2 is provided with a double-layer conductive layer. The second conductive layer 201 and the first conductive layer 101 can be formed by a synchronous process. The third conductive layer 202 and the second conductive layer 201 are connected through a via 3 to realize the connection with the ground wire 16.

[0046] Copper plating is provided on the inner wall of the via 3 to form a connecting conductive layer to realize the electrical connection between the second conductive layer 201 and the third conductive layer 202.

[0047] Both the second conductive layer 201 and the third conductive layer 202 can be made of copper material, but are not limited thereto.

[0048] In an exemplary embodiment, the orthographic projection of the third conductive layer 202 on the base layer 12 at least partially overlaps with the orthographic projection of the second conductive layer 201 on the base layer 12. The via 3 is provided in the overlapping area to realize the electrical connection between the second conductive layer 201 and the third conductive layer 202.

[0049] In an exemplary embodiment, the orthographic projection of the third conductive layer 202 on the base layer 12 is greater than or equal to the orthographic projection of the second conductive layer 201 on the base layer 12.

[0050] In application, the third conductive layer 202 is used to be electrically connected to the fourth conductive layer 5 on the cover plate 4 to realize grounding. Therefore, it is necessary to ensure the conductive area of the third conductive layer 202 to improve the grounding efficiency.

[0051] In an exemplary embodiment, the orthographic projection of the third conductive layer 202 on the base layer 12 coincides with the orthographic projection of the second conductive layer 201 on the base layer 12. Ensuring the overlapping area of the second conductive layer 201 and the third conductive layer 202 in the direction perpendicular to the base layer 12 is beneficial to the setting of the via 3, and thus beneficial to the connection between the second conductive layer 201 and the third conductive layer 202.

[0052] Exemplarily, the aperture of the via 3 and the number of the vias 3 can be set according to actual needs. One or more vias 3 can be provided on the base layer 12 to realize the electrical connection between the second conductive layer 201 and the third conductive layer 202.

[0053] In an exemplary embodiment, an insulating protective layer 8 is provided on the side of the base layer 12 away from the first conductive layer 101.

[0054] The insulating protective layer 8 is connected to the base layer 12 through the AD adhesive layer 7. The material of the AD adhesive layer can be PSA (pressure-sensitive adhesive), but is not limited thereto.

[0055] In an exemplary embodiment, the first region 1 and the conductive functional region 2 are integrally connected to form a T-shaped structure. Along the first direction, the base layer 12 includes a first side away from the wiring region. Along the first direction, the conductive functional region 2 includes a second side on the same side as the first side, and the first side and the second side are flush.

[0056] In the second direction, the conductive functional region 2 is provided on at least one side of the first region 1. Then, the first region 1 and the conductive functional region 2 are integrally connected to form a T-shaped structure. In the first direction, the conductive functional region 2 is located at one end of the first region 1 where the bonding region 11 is provided. The first side and the second side being flush facilitates the overall aesthetics and spatial distribution of the flexible printed circuit board 10.

[0057] In an exemplary embodiment, the base layer 12 and the base layer 12 are connected to form a T-shaped base layer. The T-shaped base layer includes a central region for setting the first conductive layer 101 or the second conductive layer 201, and a peripheral region located outside the central region.

[0058] In the second direction, the conductive functional region 2 is provided on at least one side of the first region 1. Then, the first region 1 and the conductive functional region 2 are integrally connected to form a T-shaped structure.

[0059] The first region 1 and the conductive functional region 2 can adopt an integral structure to simplify the process setting. During the manufacturing process, the base layer 12 and the base layer 12 are integrally formed. The first conductive layer 101 and the second conductive layer 201 are formed on the first side of the base layer 12 by a synchronous process. The third conductive layer 202 is formed on the second side of the base layer 12 opposite to the first side. Then, cutting is required to obtain the required shape, size, etc. To avoid the risk of short circuit of the conductive layer caused by particles formed by carbonization of the base layer 12 during cutting, the base layer 12 needs to be expanded. That is, the T-shaped base layer includes a central region for setting the first conductive layer 101 or the second conductive layer 201, and a peripheral region located outside the central region. The width of the peripheral region can be 0.2 - 0.3 mm, but is not limited thereto.

[0060] Exemplarily, the material of the base layer 12 is PI (polyimide), but is not limited thereto.

[0061] In an exemplary embodiment, along the first direction, the bonding area 11 includes a plurality of signal connection pins 13 arranged at intervals, and the ground pin 14 and the adjacent signal connection pin 13 are arranged at intervals.

[0062] An embodiment of the present disclosure further provides a display module, including a display panel, a cover plate 4, and the flexible printed circuit board 10 as described above disposed between the display panel and the cover plate 4;

[0063] The flexible printed circuit board 10 is bonded and connected to the display panel. A fourth conductive layer 5 is provided at the edge of the cover plate 4, and the conductive functional area 2 of the flexible printed circuit board 10 is electrically connected to the fourth conductive layer 5.

[0064] The conductive functional area 2 is connected to the fourth conductive layer 5 to achieve grounding. It is connected to the cover plate 4. When the user uses it, it directly touches the cover plate 4, which can prevent the generation of static electricity while grounding.

[0065] To further improve the grounding efficiency, the display module further includes a frame surrounding the cover plate 4. The frame can be a metal frame, and the metal frame is in contact with the fourth conductive layer 5.

[0066] In an exemplary embodiment, the cover plate 4 includes a first surface facing the display panel, a second surface away from the display panel, and a first side surface located between the first surface and the second surface. The first side surface is close to the flexible printed circuit board 10. The fourth conductive layer 5 includes a first sub-conductive layer 51 provided at the edge of the first surface close to the first side surface, a second sub-conductive layer 52 provided on the first side surface, and a third sub-conductive layer 53 provided at the edge of the second surface close to the first side surface;

[0067] The first sub-conductive layer 51, the second sub-conductive layer 52, and the third sub-conductive layer 53 enclose a U-shaped structure.

[0068] The second surface is the touch surface of the user. The fourth conductive layer 5 is divided into the first sub-conductive layer 51, the second sub-conductive layer 52, and the third sub-conductive layer 53, which can effectively achieve grounding.

[0069] In an exemplary embodiment, the cover plate 4 includes a light-transmitting area corresponding to the display area of the display panel, and a light-shielding area located outside the light-transmitting area. The orthographic projection of the first sub-conductive layer 51 on the cover plate 4 is located in the light-shielding area, and the orthographic projection of the third sub-conductive layer 53 on the cover plate 4 is located in the light-shielding area.

[0070] The positive projection of the third sub-conductive layer 53 on the cover plate 4 is located within the light-shielding area and does not exceed the light-shielding area, so as to avoid affecting the normal display of the display module.

[0071] Exemplarily, an ink layer is provided on the first surface and / or the second surface of the cover plate 4, and the ink layer covers the light-shielding area to effectively achieve light shielding and prevent light leakage.

[0072] In an exemplary embodiment, the flexible printed circuit board 10 and the cover plate 4 are connected by a conductive foam adhesive 6.

[0073] In an exemplary embodiment, in the direction perpendicular to the cover plate 4, the height of the conductive foam adhesive 6 is 0.3 - 0.4 mm, and this is not limited thereto. As long as the connection between the third conductive layer 202 and the fourth conductive layer 5 can be ensured and the connection stability between the cover plate 4 and the display panel is not affected, it is acceptable.

[0074] Exemplarily, a polarizer 200 is provided on the light-emitting layer of the display panel, and the side of the polarizer 200 away from the display panel is connected to the cover plate 4 through an optical adhesive layer 300.

[0075] In an exemplary embodiment, the positive projection of the conductive functional area 2 of the flexible printed circuit board 10 on the cover plate 4 is located within the positive projection of the conductive foam adhesive 6 on the cover plate 4.

[0076] Adopting the above solution ensures the connection area between the conductive foam adhesive 6 layer and the conductive functional area 2. The larger the contact area, the smaller the impedance. In one embodiment, each side of the conductive foam adhesive 6 layer extends outward by 0.3 - 0.5 mm relative to the corresponding side of the conductive functional area 2, but this is not limited thereto.

[0077] Exemplarily, the conductive functional area 2 is generally rectangular, and the area of the conductive functional area 2 is 2.8 - 4 mm 2 and this is not limited thereto.

[0078] In an exemplary embodiment, the display panel includes a display substrate 100 and a touch control substrate 200 located on the light-emitting side of the display substrate 100, and the flexible printed circuit board 10 is bonded and connected to the touch control substrate 200.

[0079] The flexible printed circuit board further includes a conductive adhesive 400. The flexible printed circuit board is connected to the touch control substrate 200 through the conductive adhesive 400. The conductive adhesive 400 is provided on the side of the first conductive layer 101 away from the base layer and the side of the second conductive layer 201 away from the base layer.

[0080] An embodiment of the present disclosure further provides a display device, including the above-mentioned display module.

[0081] It can be understood that the above embodiments are merely exemplary embodiments adopted to illustrate the principles of the present disclosure. However, the present disclosure is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present disclosure, and these modifications and improvements are also regarded as the protection scope of the present disclosure.

Claims

1. A flexible printed circuit board, wherein, It includes a first region extending along a first direction. Along the first direction, the first region includes an adjacent bonding region and a routing region. Along a second direction, a conductive functional region is provided on at least one side of the bonding region. The conductive functional region is electrically connected to a ground wire in the routing region for grounding. The second direction is set at an angle to the first direction. The flexible printed circuit board includes a base layer. The conductive functional region includes two conductive layers located on at least one side of the base layer. The two conductive layers are electrically connected through vias. The first region and the conductive functional region are integrally connected to form a T-shaped structure. Along the first direction, the base layer includes a first side away from the routing region. Along the first direction, the conductive functional region includes a second side on the same side as the first side. The first side and the second side are flush.

2. The flexible printed circuit board according to claim 1, wherein, The bonding region includes signal connection pins and ground pins located on at least one side of the signal connection pins along the first direction. The routing region includes signal traces connected to the signal connection pins and the ground wire located on at least one side of the signal traces along the first direction. The ground wire and the corresponding conductive functional region are on the same side of the first region.

3. The flexible printed circuit board according to claim 2, wherein, It includes a base layer, a first conductive layer located in the first region, a second conductive layer and a third conductive layer located in the conductive functional region. The first conductive layer is located on the first side of the base layer and includes the signal traces, the signal connection pins, the ground wire and the ground pins. The second conductive layer is located on the first side of the base layer, and the second conductive layer is electrically connected to the ground pins. The third conductive layer is located on the second side of the base layer opposite to the first side. The third conductive layer is electrically connected to the second conductive layer through vias penetrating the base layer.

4. The flexible printed circuit board according to claim 3, wherein, The orthographic projection of the third conductive layer on the base layer at least partially overlaps with the orthographic projection of the second conductive layer on the base layer.

5. The flexible printed circuit board according to claim 3, wherein, An insulating protective layer is provided on the side of the base layer away from the first conductive layer.

6. The flexible printed circuit board according to claim 2, wherein, Along the first direction, the bonding region includes a plurality of signal connection pins arranged at intervals. The ground pins and the adjacent signal connection pins are arranged at intervals.

7. A display module, wherein, It includes a display panel, a cover plate and the flexible printed circuit board according to any one of claims 1-6 provided between the display panel and the cover plate. The flexible printed circuit board is bonded to the display panel. A fourth conductive layer is provided at the edge of the cover plate. The conductive functional region of the flexible printed circuit board is electrically connected to the fourth conductive layer.

8. The display module according to claim 7, wherein, The cover plate includes a first surface facing the display panel, a second surface away from the display panel, and a first side surface located between the first surface and the second surface. The first side surface is close to the flexible printed circuit board. The fourth conductive layer includes a first sub-conductive layer provided at the edge of the first surface close to the first side surface, a second sub-conductive layer provided on the first side surface, and a third sub-conductive layer provided at the edge of the second surface close to the first side surface. The first sub-conductive layer, the second sub-conductive layer and the third sub-conductive layer enclose a U-shaped structure.

9. The display module according to claim 8, wherein, The cover plate includes a light-transmitting area corresponding to the display area of the display panel and a light-shielding area located outside the light-transmitting area. The orthographic projection of the first sub-conductive layer on the cover plate is located within the light-shielding area, and the orthographic projection of the third sub-conductive layer on the cover plate is located within the light-shielding area.

10. The display module according to claim 8, wherein, The flexible printed circuit board and the cover plate are connected by a conductive foam adhesive.

11. The display module according to claim 10, wherein, In the direction perpendicular to the cover plate, the height of the conductive foam adhesive is 0.3 - 0.4 mm.

12. The display module according to claim 10, wherein, The orthographic projection of the conductive functional area of the flexible printed circuit board on the cover plate is located within the orthographic projection of the conductive foam adhesive on the cover plate.

13. The display module according to claim 7, wherein, The display panel includes a display substrate and a touch control substrate located on the light-emitting side of the display substrate, and the flexible printed circuit board is bonded and connected to the touch control substrate.

14. A display device, wherein, It includes the display module according to any one of claims 7 - 13.

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