Flexible circuit board and display device

Abstract

The application discloses a flexible circuit board and a display device. The front surface of the flexible circuit board is provided with a device area. The back surface of the flexible circuit board is provided with a device corresponding area corresponding to the device area. The device corresponding area is provided with a reinforcing pad. The back surface of the flexible circuit board is provided with a back adhesive assembly. The back adhesive assembly comprises: a buffer tape located on the back surface of the flexible circuit board and adjacent to the reinforcing pad; and a back adhesive layer laminated on the back surface of the flexible circuit board and covering or avoiding the buffer tape. The flexible circuit board can buffer the vertical distance between the reinforcing pad and the back surface of the flexible circuit board through the buffer tape. After the back adhesive layer is attached to the back surface of the flexible circuit board, the thickness change of the back adhesive layer is more gentle. The pulling stress generated by the vertical distance between the reinforcing pad and the back surface of the flexible circuit board on the back adhesive layer is reduced. The problems of adhesive peeling, reverse separation and mold printing caused by the pulling of the back adhesive layer are avoided.

Description

Technical Field

[0001] This application belongs to the field of display device technology, and in particular relates to a flexible circuit board and a display device. Background Technology

[0002] Currently, Organic Light Emitting Diode (OLED) displays, due to their advantages such as self-illumination, fast response, low power consumption, flexibility, ultra-thinness, and wide color gamut, have begun to be widely used in terminal products such as mobile phones. Figure 1 As shown, in order to narrow the bottom bezel, a pad bending process is often used to bend the pad under the panel layer (PNL) and the flexible printed circuit (FPC) to the back of the display module, and then connect it to the heat dissipation film layer (Super Clean Foam, SCF) on the back of the display module through the adhesive backing of the flexible printed circuit.

[0003] In related technologies, issues such as peeling, reverse release, or mold residue problems exist with the adhesive backing of circuit boards. It should be noted that the information disclosed in the background section above is only for enhancing the understanding of the background of this disclosure and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] This application aims to at least partially solve the technical problems of reverse release and molding caused by the step differences in different areas of the flexible circuit board adhesive. To this end, this application provides an adhesive assembly, a flexible circuit board, and a display device.

[0005] This application provides a flexible circuit board, wherein the front side of the flexible circuit board has a device area, the back side of the flexible circuit board has a device corresponding area corresponding to the device area, the device corresponding area has a reinforcing pad, and the back side of the flexible circuit board has an adhesive backing assembly, the adhesive backing assembly comprising:

[0006] A buffer strip is located on the back of the flexible circuit board and adjacent to the reinforcing pad;

[0007] An adhesive backing layer is stacked on the back of the flexible circuit board and covers or avoids the buffer strip.

[0008] In some embodiments, the thickness of the buffer strip is less than the thickness of the reinforcing pad relative to the back side of the flexible circuit board.

[0009] In some embodiments, the thickness of the adhesive layer corresponding to the reinforcing pad is different from the thickness of the adhesive layer corresponding to the remaining area on the back of the flexible circuit board.

[0010] In some embodiments, the adhesive backing layer avoids the buffer strip, and the adhesive backing layer is divided into at least a first adhesive backing layer and a second adhesive backing layer with the buffer strip as the boundary.

[0011] In some embodiments, the thickness of the first adhesive layer and the second adhesive layer are different, and the thickness of the buffer strip is less than the thickness difference between the reinforcing pad and the adjacent first adhesive layer or second adhesive layer.

[0012] In some embodiments, the material of the buffer strip is selected from any one or more of polyethylene terephthalate, foam plastic, and graphite.

[0013] In some embodiments, the distance between the buffer strip and the boundaries of each region on the flexible circuit board is 0.1 mm to 1.8 mm.

[0014] In some embodiments, a fingerprint hole is formed on the flexible circuit board, and an electronic shielding film is stacked on the back of the flexible circuit board, wherein the electronic shielding film avoids the fingerprint hole and the corresponding area of ​​the device; wherein, the distance between the buffer strip and the boundary of the corresponding area of ​​the device is 1.5±0.1mm; the distance between the buffer strip and the boundary of the electronic shielding film is 0.5±0.1mm; the distance between the buffer strip and the boundary of the fingerprint hole is 0.2±0.1mm; the distance between the buffer strip and the boundary of the adhesive layer is 0.3±0.1mm; and the distance between the buffer strip and the boundary of the flexible circuit board is 0.3±0.1mm.

[0015] In some embodiments, the buffer strip has an adhesive layer on the side adjacent to the flexible circuit board.

[0016] This application also provides a display device, which includes the flexible circuit board described above.

[0017] The embodiments of this application have at least the following beneficial effects:

[0018] The aforementioned flexible circuit board, by setting a buffer strip on the back of the flexible circuit board and placing the buffer strip adjacent to the reinforcing pad, can buffer the vertical distance between the reinforcing pad and the back of the flexible circuit board. This allows the thickness change of the adhesive layer after it is pasted on the back of the flexible circuit board to be more gradual, reducing the tensile stress on the adhesive layer caused by the vertical distance between the reinforcing pad and the back of the flexible circuit board. This avoids problems such as adhesive peeling, reverse release, and mold printing caused by the adhesive layer being stretched. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 A schematic diagram showing the positional relationship between the flexible circuit board and the display module is shown.

[0021] Figure 2 A top view is shown when the adhesive backing on the flexible circuit board is stretched and flush.

[0022] Figure 3 It shows Figure 2 Cross-sectional view of a flexible circuit board;

[0023] Figure 4 This shows a cross-sectional view of the device-corresponding area on the back of the flexible circuit board with reinforcing pads.

[0024] Figure 5 A schematic diagram of the flexible circuit board structure in an embodiment of this application is shown.

[0025] Figure 6 It shows Figure 5 A sectional view of the flexible circuit board along the AA direction;

[0026] Figure 7 It shows Figure 5 A BB-direction cross-sectional view of the flexible circuit board in the middle;

[0027] Figure 8 A schematic diagram of the flexible circuit board structure is shown in another embodiment of this application;

[0028] Figure 9 It shows Figure 8 A cross-sectional view of the flexible circuit board in the CC direction;

[0029] Figure 10 It shows Figure 8 A DD-direction cross-sectional view of the flexible circuit board.

[0030] Figure label:

[0031] 1000 Display device; 11 Release film; 12 Adhesive backing; 100 Adhesive backing assembly; 110 Adhesive backing release film; 111 Release film handle; 120 Adhesive backing layer; 121 First adhesive backing layer; 122 Second adhesive backing layer; 130 Buffer strip; 131 First buffer strip; 132 Second buffer strip; 200 Flexible circuit board; 210 Flexible circuit board body; 220 Reinforcing pad; 221 Double-sided adhesive; 230 Device area; 231 Boundary of corresponding device area; 240 Electronic shielding film; 241 Boundary of electronic shielding film; 250 Fingerprint hole; 300 Display module; 310 Glass cover layer; 320 Transparent adhesive layer; 330 Polarizing layer; 340 Panel layer; 350 Protective film layer; 360 Heat dissipation film layer; 370 Driver chip; 380 Pad. Detailed Implementation

[0032] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0033] Furthermore, reference numerals and / or reference letters may be repeated in different examples in this application. Such repetition is for simplification and clarity purposes and does not in itself indicate a relationship between the various embodiments and / or settings discussed. In addition, this application provides examples of various specific processes and materials; however, those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0034] This application is described below with reference to the accompanying drawings and specific embodiments:

[0035] The first major aspect of this application provides a flexible circuit board 200, such as Figure 4 and Figure 5 As shown, the flexible circuit board 200 of this embodiment has a device area 230 on the front side and a device corresponding area corresponding to the device area 230 on the back side. The device corresponding area is provided with a reinforcing pad 220. The flexible circuit board 200 has an adhesive backing assembly 100 on the back side. The adhesive backing assembly 100 includes: a buffer strip 130 located on the back side of the flexible circuit board 200 and adjacent to the reinforcing pad 220; and an adhesive backing layer 120 stacked on the back side of the flexible circuit board 200 and covering or avoiding the buffer strip 130.

[0036] In this embodiment, the flexible circuit board 200 has a buffer strip 130 on its back side, which is adjacent to the reinforcing pad 220. This buffer strip 130 can buffer the vertical distance between the reinforcing pad 220 and the back side of the flexible circuit board 200, making the thickness change of the adhesive layer 120 after it is pasted on the back side of the flexible circuit board 200 more gradual. This reduces the tensile stress on the adhesive layer 120 caused by the vertical distance between the reinforcing pad 220 and the back side of the flexible circuit board, and avoids problems such as adhesive detachment, reverse release, and mold printing caused by the adhesive layer 120 being stretched.

[0037] Based on the same inventive concept, a second aspect of this application also provides a display device 1000, which includes the aforementioned flexible circuit board 200.

[0038] Since the display device 1000 provided by the present invention includes the adhesive backing assembly 100 or the flexible circuit board 200 of the above-mentioned technical solutions, the display device 1000 provided by the present invention has all the beneficial effects of the adhesive backing assembly 100 or the flexible circuit board 200 of the above-mentioned technical solutions, which will not be elaborated here.

[0039] In the display device 1000, such as Figure 1 As shown, in order to narrow the bottom bezel, the display device 1000 often adopts a pad bending process to bend the panel layer 340 under the pad 380 and the flexible circuit board 200 to the back of the display module 300, and connects them to the heat dissipation film layer 360 on the back of the display module 300 through the adhesive 12 on the back of the flexible circuit board 200. The display module 300 has a glass cover layer 310 (CG), a transparent adhesive layer 320 (Optically Clear Adhesive, TOCA), a polarizing layer 330 (POL), a panel layer 340 (PNL), a protective film layer 350 (Back Film, BF), and a heat dissipation film layer 360 (Super Clean Foam, SCF) stacked sequentially in the thickness direction. The panel layer 340 is bent to the back of the display module 300 and connected to the flexible circuit board 200. The portion of the panel layer 340 bent to the back of the display module 300 has a protective film layer 350, a pad 380, and a driver chip 370. The protective film layer 350 is located on the side of the panel layer 340 adjacent to the back of the display module 300, the pad 380 (PET) is located on the side of the protective film layer 350 adjacent to the back of the display module 300, and the driver chip 370 (Integrated Circuit, IC) is located on the side of the panel layer 340 away from the display module 300.

[0040] The flexible circuit board 200 includes a flexible circuit board body 210, reinforcing pads 220, and a device area 230, wherein the flexible circuit board body 210 has a multi-layer structure. Figure 2and Figure 3 In the flexible circuit board 200 shown, the back of the flexible circuit board 200 does not employ a reinforcement design in the corresponding area of ​​the device. The adhesive 12 is typically designed as a single, continuous layer, laid flat on the back of the flexible circuit board 200. The adhesive layer 120 is stacked on the release film 11, and the release film 11 has handles protruding from the adhesive 12. By holding the handles on the release film 11, the adhesive 12 can be pulled out and adhered to the back of the flexible circuit board 200. However, in cases such as Figure 4 In the flexible circuit board 200 shown, due to the reduced number of structural layers in the flexible circuit board body 210, reinforcing pads 220 need to be placed in the corresponding areas of the components on the back side of the flexible circuit board 200. The reinforcing pads 220 are attached to the back side of the flexible circuit board 200 with double-sided adhesive 221 to reinforce the component area 230 of the flexible circuit board 200. A certain thickness difference will be formed on the back side of the flexible circuit board 200 between the reinforcing pads 220 and the other areas. If the adhesive 12 is designed to be flush with the reinforcing pad 220, the thickness of the adhesive 12 will increase significantly, taking up too much space in the terminal device. If the thickness of the adhesive 12 is reduced, there will be a thickness difference between the adhesive 12 and the back area of ​​the reinforcing pad 220 and the adjacent flexible circuit board 200. After bonding, the device area 230 will be stretched. When the thickness difference between the reinforcing pad 220 and the back area of ​​the adjacent flexible circuit board 200 is too large, firstly, the adhesive 12 is easily torn apart, causing it to fall off; secondly, it is easy to cause molding around the device area 230; in addition, it will also cause the release film 11 to lift the adhesive 12 at the thickness change point, causing reverse release problem.

[0041] To avoid the problems of adhesive backing 12 peeling and molding caused by the thickness difference between the reinforcing pad 220 and the back area of ​​the adjacent flexible circuit board 200, this application proposes to provide a buffer strip 130 on the back of the flexible circuit board 200, and to place the buffer strip 130 adjacent to the reinforcing pad 220. In this way, the buffer strip 130 balances the thickness difference between the reinforcing pad 220 and the back area of ​​the adjacent flexible circuit board 200, making the thickness change between the reinforcing pad 220 and the back area of ​​the adjacent flexible circuit board 200 more gradual. This reduces the bending degree of the adhesive backing layer 120 in the thickness change area between the reinforcing pad 220 and the back of the flexible circuit board 200. Through verification, the buffer strip 130 can effectively solve the problems of peeling, peeling, or molding caused by the adhesive backing layer 120 being stretched.

[0042] Optionally, the adhesive assembly 100 in this embodiment further includes an adhesive release film 110. The adhesive release film 110 is stacked on the side of the adhesive layer 120 away from the flexible circuit board 200. The adhesive release film 110 provides strength and rigidity support for the adhesive assembly 100, thereby facilitating the adhesion of the adhesive layer 120 to the back of the flexible circuit board 200. After the adhesive layer 120 is adhered to the back of the flexible circuit board 200, the adhesive release film 110 can be removed from the adhesive layer 120. More preferably, the size of the adhesive layer 120 corresponds to the back of the flexible circuit board 200, and the adhesive release film 110 may be provided with a release film handle 111 protruding from the flexible circuit board 200 and the adhesive layer 120.

[0043] In this embodiment, as Figures 5 to 7 As shown, the adhesive layer 120 can avoid the buffer strip 130, which can be attached to the back of the flexible circuit board 200 to compensate for the thickness variation area on the back of the flexible circuit board 200 and provide a thickness buffering effect.

[0044] In other embodiments, such as Figures 8 to 10 As shown, the adhesive layer 120 can cover the buffer strip 130, that is, the buffer strip 130 can be disposed between the adhesive layer 120 and the flexible circuit board 200. One side of the buffer strip 130 can be attached to the back of the flexible circuit board 200 to compensate for the thickness variation area on the back of the flexible circuit board 200 and provide a thickness buffering effect. The other side of the buffer strip 130 is attached to the adhesive layer 120, and can then be attached to the heat dissipation film layer 360 through the adhesive layer 120. In addition, since the other side of the buffer strip 130 is attached to the adhesive layer 120, it can be disposed together with the adhesive layer 120 on the back of the flexible circuit board 200, which can reduce the number of operation steps and improve work efficiency.

[0045] As an alternative implementation, the thickness of the buffer strip 130 is less than the thickness of the reinforcing pad 220 relative to the back of the flexible circuit board.

[0046] In this embodiment, as Figures 5 to 7As shown, a reinforcing pad 220 is provided in the corresponding area of ​​the device on the back side of the flexible circuit board 200. Therefore, the thickness of the reinforcing pad 220 on the back side of the flexible circuit board 200 is relatively large, while the thickness of the other areas of the flexible circuit board 200 is relatively small. Because the reinforcing pad 220 is located on the back side of the flexible circuit board 200, there is an overall thickness difference on the back side of the flexible circuit board 200. Therefore, a design scheme where the adhesive layer 120 is flush with the back side cannot be adopted. A buffer strip 130 is needed to compensate and thicken the remaining areas on the back side of the flexible circuit board 200, excluding the reinforcing pad 220. Therefore, the preferred thickness range for compensation and thickening is the thickness of the reinforcing pad 220 relative to the back side of the flexible circuit board 200. At the same time, to avoid the thickness of the remaining areas of the flexible circuit board 200 exceeding the thickness of the reinforcing pad 220 due to the thickness compensation of the buffer strip 130, the thickness of the buffer strip 130 needs to be less than the thickness of the reinforcing pad 220 relative to the back side of the flexible circuit board 200.

[0047] As an alternative implementation, the thickness of the adhesive layer 120 corresponding to the reinforcing pad 220 is different from the thickness of the adhesive layer 120 corresponding to the remaining area on the back of the flexible circuit board 200.

[0048] In this embodiment, the reinforcing pad 220 and the remaining areas of the flexible circuit board 200 need to be bonded and fixed to the heat dissipation film layer 360 on the back of the display module 300 by the adhesive layer 120. In order to avoid or reduce the bending degree of the adhesive layer 120 due to the thickness variation, the thickness of the adhesive layer 120 can be different from the thickness of the reinforcing pad 220 and the remaining areas of the flexible circuit board 200, respectively. That is, the adhesive layer 120 area can be divided according to the relative thickness of each area on the back of the flexible circuit board 200, and different adhesive layer 120 thicknesses can be set for different areas, so that some thickness difference can be compensated by the adhesive layer 120.

[0049] As a further optional implementation, the adhesive layer 120 avoids the buffer strip 130, and the adhesive layer 120 is divided into at least a first adhesive layer 121 and a second adhesive layer 122 with the buffer strip 130 as the boundary.

[0050] In this embodiment, as Figures 5 to 7As shown, the adhesive backing layer 120 is segmented with the buffer strip 130 as the boundary. Therefore, the first adhesive backing layer 121 and the second adhesive backing layer 122 can have different structures depending on the placement of the buffer strip 130, so as to match the structure of the buffer strip 130 and the flexible circuit board 200. Furthermore, there are thickness differences on different sides of the reinforcing pad 220. If the adhesive backing layer 120 adopts a one-piece design, then when there are thickness differences on adjacent sides of the reinforcing pad 220, the adhesive backing layer 120 is prone to wrinkles and unevenness at these locations. Therefore, dividing the adhesive backing layer 120 into different areas with the buffer strip 130 as the boundary can avoid the problem of wrinkles in the adhesive backing layer 120.

[0051] As an alternative implementation, the first adhesive layer 121 and the second adhesive layer 122 have different thicknesses, and the thickness of the buffer strip 130 is less than the thickness difference between the reinforcing pad 220 and the adjacent first adhesive layer 121 or second adhesive layer 122.

[0052] In this embodiment, because the device area 230 is positioned differently on the front side of the flexible circuit board 200, the corresponding device area is positioned differently on the back side of the flexible circuit board 200. Simultaneously, the position of the reinforcing pad 220 positioned on the corresponding device area on the flexible circuit board 200 also changes accordingly. For example... Figures 5 to 7 As shown, the reinforcing pad 220 is located in the upper left corner of the back of the flexible circuit board 200. Therefore, the significant thickness at the right and lower edges of the reinforcing pad 220 has a considerable impact on the adhesive layer 120. Therefore, buffer strips 130 can be provided on the right and lower sides of the reinforcing pad 220 respectively to compensate for the thickness difference between the right and lower edges of the buffer reinforcing pad 220.

[0053] In this embodiment, as Figure 5As shown, the back surface of the flexible circuit board 200 can be divided into multiple regions. Specifically, the back surface of the flexible circuit board 200 can be divided into an upper half and a lower half, with the reinforcing pad 220 as a reference. The thickness of the reinforcing pad 220 in the upper half of the flexible circuit board 200 differs from the position of the remaining areas in the upper half of the back surface of the flexible circuit board 200 and the height of the lower half of the back surface of the flexible circuit board 200. Therefore, based on the regional division of the back surface of the flexible circuit board 200, a first adhesive layer 121 can be provided in the upper half of the flexible circuit board 200. The first adhesive layer 121 is divided into two parts by the reinforcing pad 220. While ensuring sufficient bonding strength, the first adhesive layer 121 is positioned as far away from the reinforcing pad 220 as possible. This allows for the placement of a first buffer strip 131 in the area between the reinforcing pad 220 and the first adhesive layer 121. The first buffer strip 131 compensates for the thickness difference between the reinforcing pad 220 and the first adhesive layer 121. The thickness of the first buffer strip 131 is determined based on the thickness difference between the reinforcing pad 220 and the first adhesive layer 121. Let the thickness of the first buffer strip 131 be denoted as E1, the thickness of the first adhesive layer 121 as H1, and the thickness of the area around the reinforcing pad 220 as F. The thickness E1 of the first buffer strip 131 satisfies E1 ≤ F - H1. Flexible circuit board 200 Figure 5 A second adhesive layer 122 can be provided in the lower half. A second buffer strip 132 can be provided in the area between the second adhesive layer 122 and the first adhesive layer 121, and in the area between the second adhesive layer 122 and the reinforcing pad 220. The second buffer strip 132 compensates for the thickness difference between the second adhesive layer 122 and the reinforcing pad 220, and the thickness of the second buffer strip 132 is determined according to the thickness of the reinforcing pad 220. The thickness difference between the first adhesive layer 121 and the second adhesive layer 122 is jointly determined. The thickness of the second buffer strip 132 is denoted as E2, and the thickness of the second adhesive layer 122 is denoted as H2. Therefore, the thickness E2 of the second buffer strip 132 is between (F-H2) and (|H2-H1|), meaning that the thickness E2 of the second buffer strip 132 is between the thickness difference between the reinforcing pad 220 and the second adhesive layer 122, and the thickness difference between the first adhesive layer 121 and the second adhesive layer 122. Alternatively, the second adhesive layer 122 can be further divided into left and right parts. The thickness of the left second adhesive layer 122 is determined by the thickness difference between the reinforcing pad 220 and the back of the flexible circuit board 200, and the thickness of the right second adhesive layer 122 is determined by the thickness difference between the first adhesive layer 121 and the back of the flexible circuit board 200.

[0054] As an alternative implementation, the material of the buffer strip 130 is selected from any one or more of polyethylene terephthalate (PET), foam plastic (FOAM), and graphite.

[0055] In the flexible circuit board 200 of this application, the material of the buffer strip 130 can be selected from materials with a supporting function, including but not limited to polyethylene terephthalate (PET), foam plastic (FOAM), and graphite. When graphite is used as one or more materials of the buffer strip 130, the buffer strip 130 can not only buffer the vertical distance between relatively thick and relatively thin areas, but also has a heat dissipation function.

[0056] As an optional implementation, the spacing between the buffer strip 130 and the boundaries of each area on the flexible circuit board 200 is 0.1 mm to 1.8 mm.

[0057] In the flexible circuit board 200 of this application, the shape of the buffer strip 130 is not limited. The shape of the buffer strip 130 can be set according to the supplier's technical capabilities, or it can be adaptively adjusted according to the contour of the reinforcing pad 220 or other structures of the flexible circuit board 200. Optionally, the distance between the buffer strip 130 and the boundaries of each area on the flexible circuit board 200 is 0.1mm to 1.8mm. On the one hand, this facilitates the positioning of the buffer strip 130 and avoids the buffer strip 130 from crossing the boundaries of each area, which would cause thickness compensation errors. For example, if the buffer strip 130 crosses the boundary of the reinforcing pad 220, the thickness of the reinforcing pad 220 will be higher, which would cause the adhesive 12 to bend more and be stretched. On the other hand, it avoids the buffer strip 130 from crossing the boundaries of each area and interfering with each area. For example, if the buffer strip 130 crosses the boundary of the fingerprint hole 250, it would interfere with the fingerprint hole 250 area. In addition, it can also help to offset the positioning error of the buffer strip 130 and ensure that the buffer strip 130 does not cross the boundaries of each area within the positioning error range.

[0058] As a further optional implementation, such as Figure 5 As shown, a fingerprint hole 250 is formed on the flexible circuit board 200, and an electronic shielding film 240 is stacked on the back of the flexible circuit board 200, and the electronic shielding film 240 avoids the fingerprint hole 250 and the corresponding area of ​​the device; wherein, the distance Q1 between the buffer strip 130 and the boundary 231 of the corresponding area of ​​the device is 1.5±0.1mm; the distance Q2 between the boundary of the buffer strip 130 and the electronic shielding film 240 is 0.5±0.1mm; the distance Q3 between the boundary of the buffer strip 130 and the fingerprint hole 250 is 0.2±0.1mm; the distances Q4, Q5, and Q6 between the boundary of the buffer strip 130 and the adhesive layer 120 are 0.3±0.1mm; and the distance Q7 between the buffer strip 130 and the boundary of the flexible circuit board 200 is 0.3±0.1mm.

[0059] As an alternative implementation, the buffer strip 130 has an adhesive layer on the side adjacent to the flexible circuit board 200.

[0060] In this embodiment, an adhesive layer is provided on the side of the buffer strip 130 adjacent to the flexible circuit board 200, that is, the buffer strip 130 is adhesive on one side, with the adhesive side facing the flexible circuit board 200 and the non-adhesive side facing the heat dissipation film layer 360. This allows the buffer strip 130 to be adhered and fixed to the flexible circuit board 200 by the adhesive layer, so that the area where the buffer strip 130 is provided will not be subjected to pulling force after bonding.

[0061] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0062] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", and "counterclockwise" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0063] It should be noted that all directional indications in the embodiments of this application are only used to explain the relative positional relationship and movement of each component in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0064] In this application, unless otherwise expressly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0065] Furthermore, the use of terms such as "first" and "second" in this application is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0066] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0067] Furthermore, the technical solutions of the various embodiments can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0068] Although embodiments of this application have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A flexible circuit board, characterized in that, The flexible circuit board has a device area on its front side and a device corresponding area on its back side. The device corresponding area has a reinforcing pad. The back side of the flexible circuit board also has an adhesive backing assembly, which includes: A buffer strip is located on the back of the flexible circuit board and adjacent to the reinforcing pad; An adhesive backing layer is laminated on the back side of the flexible circuit board, the adhesive backing layer avoiding the buffer strip, the adhesive backing layer being at least divided into a first adhesive backing layer and a second adhesive backing layer with the buffer strip as the boundary, the first adhesive backing layer and the second adhesive backing layer having different thicknesses, and the thickness of the buffer strip being less than the thickness difference between the reinforcing pad and the adjacent first adhesive backing layer or second adhesive backing layer; and, An adhesive release film is laminated on the side of the adhesive layer away from the flexible circuit board.

2. The flexible circuit board as described in claim 1, characterized in that, The thickness of the buffer strip is less than the thickness of the reinforcing pad relative to the back side of the flexible circuit board.

3. The flexible circuit board as described in claim 1, characterized in that, The thickness of the adhesive layer corresponding to the reinforcing pad is different from the thickness of the adhesive layer corresponding to the remaining area on the back of the flexible circuit board.

4. The flexible circuit board as described in claim 1, characterized in that, The material of the buffer strip is selected from any one or more of polyethylene terephthalate, foam plastic, and graphite.

5. The flexible circuit board as described in claim 1, characterized in that, The distance between the buffer strip and the boundaries of each region on the flexible circuit board is 0.1 mm to 1.8 mm.

6. The flexible circuit board as described in claim 5, characterized in that, The flexible circuit board has a fingerprint hole, and an electronic shielding film is stacked on the back of the flexible circuit board, with the electronic shielding film avoiding the fingerprint hole and the corresponding area of ​​the device; wherein, the distance between the buffer strip and the boundary of the corresponding area of ​​the device is 1.5±0.1 mm; the distance between the buffer strip and the boundary of the electronic shielding film is 0.5±0.1 mm; the distance between the buffer strip and the boundary of the fingerprint hole is 0.2±0.1 mm; the distance between the buffer strip and the boundary of the adhesive layer is 0.3±0.1 mm; and the distance between the buffer strip and the boundary of the flexible circuit board is 0.3±0.1 mm.

7. The flexible circuit board as described in any one of claims 1 to 6, characterized in that, The buffer strip has an adhesive layer on the side adjacent to the flexible circuit board.

8. A display device, characterized in that, The display device includes a flexible circuit board as described in any one of claims 1 to 7.

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