Display device and flexible printed circuit board

Abstract

The invention provides a display device and a flexible printed circuit board. The display device comprises a flexible printed circuit board, the flexible printed circuit board is provided with at least one slit, the slit penetrates through the flexible printed circuit board in the thickness direction of the flexible printed circuit board, the first end of the slit is located in the flexible printed circuit board, and the second end of the slit is located at the edge of the flexible printed circuit board. The flexible printed circuit board is further provided with a through hole communicated with the first end of the slit. The flexible printed circuit board may include a first conductive line layer and a second conductive line layer that are electrically connected through a via hole. The length of the flexible printed circuit board is adaptively adjusted, the assembly yield and reliability of the display device are improved, the assembly process is simplified, and product loss caused by poor assembly is reduced.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to a display device and a flexible printed circuit board. Background Art

[0002] like Figure 1 As shown in the prior art, a liquid crystal display (LCD) device needs to use a backlight unit (BLU) 101 to provide a light source. The flexible printed circuit board (FPC) 103 of the backlight unit 101 needs to be plugged into a connector 1021 of a printed circuit board assembly (PCBA) 102 to achieve electrical connection. However, if the flexible printed circuit board 103 is offset from the assembly and the plugging distance is insufficient, poor contact may occur, such as Figure 2 As shown, a display exception is caused.

[0003] In order to avoid the above problems, the prior art uses the limit mark 1011 to check whether the flexible printed circuit board 103 is assembled in place. However, the limit mark 1011 itself also has the problem of position accuracy. In order to avoid the defect caused by insufficient insertion distance of the flexible printed circuit board 103 after superimposing the position accuracy of the limit mark, the distance between the limit mark and the flexible printed circuit board 103 is set to be small. This puts forward a higher precision requirement for assembly fluctuation, and manual assembly is prone to a certain loss of yield.

[0004] The length of the existing flexible printed circuit board 103 is usually fixed. If the flexible printed circuit board 103 is offset from the assembly and the plugging distance is insufficient, poor contact may occur, thereby causing display abnormality. In addition, the shrinkage of the material of the flexible printed circuit board 103 may also affect the plugging distance between the flexible printed circuit board 103 and the connector 1021, thereby causing display quality problems.

[0005] Therefore, how to design a flexible printed circuit board that can adapt to assembly deviation and material deformation to improve the assembly yield and reliability of liquid crystal display devices has become a technical problem that the industry urgently needs to solve. Summary of the invention

[0006] Embodiments of the present application provide a display device and a flexible printed circuit board, aiming to improve the assembly yield and reliability of the display device.

[0007] An embodiment of the present application provides a flexible printed circuit board, which is provided with at least one slit, wherein the slit penetrates the flexible printed circuit board in the thickness direction of the flexible printed circuit board, wherein a first end of the slit is located inside the flexible printed circuit board, and a second end of the slit is located at an edge of the flexible printed circuit board.

[0008] In the above-mentioned flexible printed circuit board, the flexible printed circuit board is provided with a through hole, and the through hole is communicated with the first end of the slit.

[0009] In the above flexible printed circuit board, a plurality of the slits are arranged in parallel.

[0010] In the above flexible printed circuit board, the second end of one of the two adjacent slits is located at one edge of the flexible printed circuit board, and the second end of the other of the two adjacent slits is located at the other edge of the flexible printed circuit board.

[0011] In the above flexible printed circuit board, at least one of the slits is perpendicular to an edge of the flexible printed circuit board.

[0012] In the above-mentioned flexible printed circuit board, at least one of the slits forms an angle of 30 degrees to 60 degrees with an edge of the flexible printed circuit board.

[0013] In the above-mentioned flexible printed circuit board, the plurality of slits include: at least one group of first slits parallel to one edge of the flexible printed circuit board; and at least one group of second slits parallel to the other edge of the flexible printed circuit board; wherein the straight line where the first slits are located is perpendicular to the straight line where the second slits are located.

[0014] In the above-mentioned flexible printed circuit board, the flexible printed circuit board includes: a first conductor layer; a second conductor layer, the film layer where the second conductor layer is located is located above the film layer where the first conductor layer is located; and a plurality of vias; wherein the conductors in the second conductor layer are electrically connected to part of the conductors in the first conductor layer through the vias.

[0015] In the above-mentioned flexible printed circuit board, the flexible printed circuit board includes a first edge and a second edge opposite to each other, the second end of the slit is located at the second edge, and the distance from the first end of the slit to the first edge is greater than half of the distance between the first edge and the second edge of the flexible printed circuit board; the wires in the second wire layer are located between the first end of the slit and the first edge of the flexible printed circuit board.

[0016] An embodiment of the present application further provides a display device, which includes a printed circuit board assembly and the above-mentioned flexible printed circuit board, wherein the printed circuit board assembly includes a connector, and the flexible printed circuit board is connected to the connector.

[0017] In an embodiment of the present application, by providing a slit on the flexible printed circuit board, adaptive adjustment of the length of the flexible printed circuit board is achieved. This technical solution enables the flexible printed circuit board to adapt to positional deviations during the assembly process, effectively reducing the requirements for assembly accuracy, thereby improving the assembly yield of the display device. The embodiment of the present application can also alleviate the stress caused by factors such as material shrinkage, and improve the stability of the product during reliability testing and normal use. This technical solution enables the flexible printed circuit board to adapt to slight deformations of the material, reduces changes in the plug-in distance caused by material shrinkage, and thus improves the long-term reliability of the display device. The embodiment of the present application reduces display anomalies caused by poor plugging, ensures the stability of the electrical connection, and improves the overall quality and reliability of the liquid crystal display device. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The diagram is a schematic diagram showing a state in which a flexible printed circuit board of a backlight module in a conventional display device is plugged into a connector of a printed circuit board assembly.

[0019] Figure 2 yes Figure 1 The diagram shows a problem that the insertion distance of the flexible printed circuit board is insufficient due to position deviation of the flexible printed circuit board.

[0020] Figure 3 is a schematic diagram of a display device provided in an embodiment of the present application.

[0021] Figure 4 1 is a schematic diagram of a first embodiment of a flexible printed circuit board of a display device provided in an embodiment of the present application.

[0022] Figure 5 1 is a schematic diagram of a second embodiment of a flexible printed circuit board of a display device provided in an embodiment of the present application.

[0023] Figure 6 1 is a schematic diagram of a third embodiment of a flexible printed circuit board of a display device provided in an embodiment of the present application.

[0024] Figure 7 1 is a schematic diagram of a fourth embodiment of a flexible printed circuit board of a display device provided in an embodiment of the present application.

[0025] Figure 8 1 is a schematic diagram of a fifth embodiment of a flexible printed circuit board of a display device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0026] The specific implementation methods of the present application are described in detail below with reference to the accompanying drawings.

[0027] The terms "first", "second" and similar words do not indicate any order, quantity or importance, but are only used to distinguish different technical features. The term "plurality" and similar words mean two or more, unless otherwise clearly defined.

[0028] The embodiments of the present application may be combined with each other.

[0029] like Figure 3 As shown, the display device provided in the embodiment of the present application includes a liquid crystal display panel, a backlight module (not shown in the figure), a timing controller TCON, a source driving circuit DD, and a power management chip (not shown in the figure, the power management chip can be integrated with the timing controller TCON into the same chip). The liquid crystal display panel includes a plurality of pixel units P, a plurality of scan lines (GL1~GLn), a plurality of data lines (DL1~DLm), a gate driving circuit GOA, etc., the plurality of pixel units P are arranged in rows and columns, the gate driving circuit GOA is electrically connected to the plurality of scan lines (GL1~GLn), the source driving circuit DD is electrically connected to the plurality of data lines (DL1~DLm), the scan lines (GL1~GLn) and the data lines (DL1~DLm) are electrically connected to the pixel units P, and the timing controller TCON is electrically connected to the gate driving circuit GOA and the source driving circuit DD.

[0030] The liquid crystal display panel includes a thin film transistor array substrate, an opposing substrate and a liquid crystal material arranged between the thin film transistor array substrate and the opposing substrate. The thin film transistor array substrate includes a substrate, a gate drive circuit GOA, a pixel unit P, a scan line (GL1~GLn), a data line (DL1~DLm), a color resistor, etc. The pixel unit P includes a thin film transistor, a pixel electrode, etc. The thin film transistor is electrically connected to the pixel electrode, the scan line (GL1~GLn) and the data line (DL1~DLm).

[0031] The gate driving circuit GOA includes a plurality of cascaded gate driving units. Each gate driving unit is electrically connected to a row of pixel units P. The gate driving unit is used to provide a scanning signal to the pixel units P.

[0032] The source driving circuit DD is used to provide a data signal to the pixel unit P.

[0033] The timing controller TCON is used to receive externally input image data, and control the gate driving circuit GOA to output a scanning signal, and control the source driving circuit DD to output a data signal.

[0034] The power management chip is used to provide the required operating voltage for each part of the display device.

[0035] like Figures 4 to 8As shown, an embodiment of the present application provides a display device, the display device includes a flexible printed circuit board 303 and a printed circuit board assembly, the printed circuit board assembly includes a connector, the flexible printed circuit board 303 is plugged (connected) to the connector, the flexible printed circuit board 303 is provided with at least one slit 3031, the slit 3031 penetrates the flexible printed circuit board 303 in the thickness direction of the flexible printed circuit board 303, the first end of the slit 3031 is located inside the flexible printed circuit board 303, and the second end of the slit 3031 is located at the edge of the flexible printed circuit board 303.

[0036] In this embodiment, the width of the slit 3031 can gradually increase from the first end to the second end. For example, the width of the slit 3031 at the first end can be set to 0.1 mm, and then gradually increase to 0.4 mm at the second end along the length direction of the slit 3031. This gradually widening technical solution can provide a larger deformation space while ensuring the integrity of the flexible printed circuit board 303. In addition, the edge of the slit 3031 can be set to be serrated or wavy instead of straight. This nonlinear edge can better disperse stress and prevent cracks from extending along the edge of the slit 3031 under stress. The period of the sawtooth or wave can be set to 0.1 mm to 0.5 mm, and the amplitude can be set to 0.02 mm to 0.1 mm.

[0037] like Figures 4 to 8 As shown, the flexible printed circuit board 303 is provided with a through hole 3032, and the through hole 3032 is connected to the first end of the slit 3031. The through hole 3032 can release stress and prevent the flexible printed circuit board 303 from being torn due to stress concentration after receiving external force.

[0038] In this embodiment, the through hole 3032 can be arranged near the first end of the slit 3031, for example, the center of the through hole 3032 can coincide with the first end of the slit 3031, or the edge of the through hole 3032 can be tangent to the first end of the slit 3031. The diameter of the through hole 3032 can be greater than the width of the slit 3031, for example, the diameter of the through hole 3032 can be 1.5 to 3 times the width of the slit 3031. In this way, the stress can be effectively dispersed to prevent the slit 3031 from further extending or tearing when subjected to force. In addition, the through hole 3032 can also serve as the starting point of the slit 3031, which is convenient for accurately controlling the position and length of the slit 3031 during the manufacturing process.

[0039] like Figures 4 to 8As shown, the shape of the through hole 3032 is circular. In this embodiment, the through hole 3032 can be non-circular, such as an ellipse, a rhombus or a polygon. This non-circular design can be optimized according to the stress distribution to better disperse the stress. For example, an elliptical through hole 3032 with a major axis parallel to the direction of the slit 3031 can be used, so that the occupation of the wire wiring space can be reduced while maintaining the stress release effect. The diameter of the minimum circumscribed circle of the through hole 3032 can be set to 2 to 5 times the thickness of the flexible printed circuit board 303.

[0040] like Figures 4 to 8 As shown, a plurality of slits 3031 are arranged in parallel. The slits 3031 may be parallel to the width direction X or the length direction Y of the flexible printed circuit board 303 .

[0041] In this embodiment, a plurality of parallel slits 3031 may be evenly distributed on the flexible printed circuit board 303. For example, the distance between two adjacent slits 3031 may be equal, and this distance may be determined according to the overall size of the flexible printed circuit board 303 and the required degree of flexibility. Generally, this distance may be set to 1 / 10 to 1 / 5 of the width of the flexible printed circuit board 303. In addition, the parallel slits 3031 may have the same length or different lengths to achieve differentiated flexibility in different areas.

[0042] In this embodiment, the lengths of the plurality of parallel slits 3031 are different. For example, the length of the slits 3031 gradually increases or decreases from one end to the other end of the flexible printed circuit board 303. In this way, the flexible printed circuit board 303 can have different flexibility characteristics in different areas. A small portion of uncut material is retained between two adjacent parallel slits 3031.

[0043] like Figures 4 to 8 As shown, the second end of one of the two adjacent slits 3031 is located at one edge of the flexible printed circuit board 303, and the second end of the other of the two adjacent slits 3031 is located at the other edge of the flexible printed circuit board 303. In this way, the deformability of the flexible printed circuit board 303 can be further enhanced.

[0044] This staggered arrangement can further enhance the deformability of the flexible printed circuit board 303. Specifically, the slits 3031 can be divided into two groups, with the second end of one group located at one edge of the flexible printed circuit board 303, and the second end of the other group located at the other edge of the flexible printed circuit board 303. The two groups of slits 3031 can be arranged alternately to form a "comb-tooth" structure. This structure can make the flexible printed circuit board 303 deform more evenly when subjected to force, avoiding stress concentration.

[0045] The staggered slits 3031 can be further optimized into a "herringbone" or "V-shaped" arrangement. Specifically, the first ends of two adjacent slits 3031 can be arranged close to each other, while the second ends extend to two opposite edges of the flexible printed circuit board 303. This technical solution can enhance the overall structural strength of the flexible printed circuit board 303 while maintaining flexibility. In addition, stress concentration structures such as micro-through holes 3032 or local thickened areas can be arranged at the vertices of the "herringbone" or "V-shaped" structures to further optimize stress distribution.

[0046] At least one of the plurality of slits 3031 is perpendicular to an edge of the flexible printed circuit board 303. Figure 4 and Figure 6 shown.

[0047] Alternatively, at least one of the plurality of slits 3031 forms an angle of 30 to 60 degrees with an edge of the flexible printed circuit board 303. Figure 5 , Figure 7 and Figure 8 The inclined slits 3031 can achieve adaptive variable length of the flexible printed circuit board 303 in both the length direction Y and the width direction X.

[0048] The slits 3031 are set to form an angle of 30 to 60 degrees with the edge of the flexible printed circuit board 303, so that the flexible printed circuit board 303 can be adaptively adjusted in both the length direction Y and the width direction X. Among them, an angle of 45 degrees may be the best choice because it can provide equal flexibility in both directions. In addition, multiple groups of slits 3031 with different angles can be set, for example, one group of 30 degrees, one group of 45 degrees, and one group of 60 degrees, to achieve more complex deformation requirements.

[0049] When the slits 3031 form an angle of 30 degrees with the edge, the flexible printed circuit board 303 is suitable for scenarios that require a larger deformation capability in the length direction Y, for example, scenarios where the flexible printed circuit board 303 in a bendable display needs to bend more significantly along the bending axis. In this case, the flexible printed circuit board 303 includes 3-5 slits 3031 at an angle of 30 degrees, and the spacing between the slits 3031 is 2-3 mm. In this way, the flexible printed circuit board 303 can have a telescopic range of 10%-15% of the original length in the length direction Y, and a telescopic range of about 5%-8% of the original width in the width direction X.

[0050] When the slits 3031 are at an angle of 45 degrees to the edge, the flexible printed circuit board 303 is suitable for scenarios where moderate deformation capability is required in both the length and width directions, for example, the flexible printed circuit board 303 in a flexible wearable device needs to adapt to the multi-directional bending of the human body surface. In this case, the flexible printed circuit board 303 includes 4-6 slits 3031 at an angle of 45 degrees, and the spacing between the slits 3031 is 1.5-2.5 mm. In this way, the flexible printed circuit board 303 can achieve a telescopic range of 8%-12% of the original size in both the length direction Y and the width direction X.

[0051] When the slits 3031 form an angle of 60 degrees with the edge, the flexible printed circuit board 303 is suitable for scenarios that require a large deformation capability in the width direction X, for example, the flexible printed circuit board 303 in the roll-up display needs to bend or stretch to a large extent in the width direction. In this case, the flexible printed circuit board 303 includes 2-4 slits 3031 with an angle of 60 degrees, and the spacing between the slits 3031 is 3-4 mm. In this way, the flexible printed circuit board 303 can achieve a stretch range of 12%-18% of the original width in the width direction X, and a stretch range of about 6%-9% of the original length in the length direction Y.

[0052] In order to achieve more complex deformation requirements, multiple groups of slits 3031 with different angles can be set on the same flexible printed circuit board 303. For example, 2-3 slits 3031 with a 30-degree angle are set at the end close to the connector, with a spacing of 2mm; 3-4 slits 3031 with a 45-degree angle are set in the middle, with a spacing of 2mm; 2-3 slits 3031 with a 60-degree angle are set at the far end, with a spacing of 3mm. In this way, the flexible printed circuit board 303 can present different deformation characteristics in different areas to adapt to complex usage scenarios. For another example, slits 3031 with angles of 30 degrees, 45 degrees and 60 degrees are alternately set, with 2-3 slits at each angle and a spacing of 2.5mm. In this way, uniform multi-directional deformation capability can be achieved on the entire flexible printed circuit board 303. For another example, from one end to the other, the angle of the slit 3031 gradually transitions from 30 degrees to 60 degrees, and a total of 6-8 slits 3031 are provided, the angle difference between adjacent slits 3031 is 5 degrees, and the spacing gradually increases from 2 mm to 3 mm. In this way, a flexible gradient can be created, so that the flexible printed circuit board 303 has different deformation characteristics at different positions.

[0053] By combining the slits 3031 of different angles and numbers, the flexible printed circuit board 303 can be adaptively adjusted in multiple directions at the same time, and the stress can be dispersed more evenly, the stress concentration points can be reduced, and the service life of the flexible printed circuit board 303 can be increased.

[0054] In this embodiment, a gradient angle design can be adopted. That is, from one end to the other end of the flexible printed circuit board 303, the angle between the slit 3031 and the edge can gradually increase from 30 degrees to 60 degrees. This technical solution can create more complex and sophisticated deformation characteristics to meet the stress requirements of different regions. In addition, multiple groups of slits 3031 with different angles can be set on the same flexible printed circuit board 303, and each group of slits 3031 is responsible for stress release in a specific direction, thereby achieving all-round flexibility control.

[0055] like Figure 4 and Figure 5 As shown, the plurality of slits 3031 include: at least one group of first slits 3031 parallel to one edge of the flexible printed circuit board 303; and at least one group of second slits 3031 parallel to the other edge of the flexible printed circuit board 303; wherein the straight line where the first slits 3031 are located is perpendicular to the straight line where the second slits 3031 are located. In this way, the deformability of the flexible printed circuit board 303 in two perpendicular directions can be enhanced.

[0056] The orthogonally arranged slits 3031 can provide a more comprehensive flexibility adjustment capability. The first slits 3031 and the second slits 3031 can be arranged alternately to form a grid-like structure. The number and length of each group of slits 3031 can be adjusted according to actual needs. For example, if the flexible printed circuit board 303 needs a greater deformation capability in one direction, the number or length of the slits 3031 in that direction can be increased. In addition, additional stress release structures, such as small through holes 3032 or micro slits 3031, can be provided near the intersection of the two groups of slits 3031.

[0057] On the basis of this orthogonal slit 3031, multiple slits 3031 are arranged in a "staircase shape". Specifically, the first slit 3031 and the second slit 3031 are arranged alternately, and the length of each group of slits 3031 changes gradually to form a step-like pattern. This technical solution can provide differentiated deformation capabilities for different areas while providing comprehensive flexibility. In addition, a stress dispersion structure, such as a diamond or cross-shaped tiny incision, can be set at the intersection of the first slit 3031 and the second slit 3031 to optimize stress distribution and prevent crack propagation.

[0058] In order to solve the problem of reduced wiring space caused by the provision of the slits 3031 and the through holes 3032, the flexible printed circuit board 303 provided in the embodiment of the present application adopts a double-layer wiring design. The flexible printed circuit board 303 includes: a first wire layer; a second wire layer, the film layer where the second wire layer is located is located above the film layer where the first wire layer is located; and a plurality of vias; wherein the wires in the second wire layer are electrically connected to part of the wires in the first wire layer through the vias.

[0059] The flexible printed circuit board 303 includes a first edge and a second edge opposite to each other, the second end of the slit 3031 is located at the second edge, and the distance from the first end of the slit 3031 to the first edge is greater than half of the distance between the first edge and the second edge of the flexible printed circuit board 303; the wires in the second wire layer are located between the first end of the slit 3031 and the first edge of the flexible printed circuit board 303. In this way, it can be ensured that the space occupied by the slit 3031 in the width direction X of the flexible printed circuit board 303 is less than or equal to half of the space of the flexible printed circuit board 303 in the width direction X, so that the setting of all metal traces can be completed by setting two layers of metal traces.

[0060] In this embodiment, the wires in the second wire layer are arranged between the first end of the slit 3031 and the first edge of the flexible printed circuit board 303, and may be a comb-shaped structure. Specifically, the wires in the second wire layer may present a plurality of parallel "tooth"-shaped structures, and these "tooth"-shaped structures extend perpendicular to the direction of the slit 3031. This comb-shaped structure can improve the overall flexibility of the flexible printed circuit board 303 while ensuring electrical connection, so that it can better adapt to bending and twisting.

[0061] In this embodiment, the density of the wires may be low in the area near the first end of the slit 3031, and the density of the wires may gradually increase in the area away from the slit 3031. For example, the density of the wires may be gradually increased from 10 per millimeter to 30 per millimeter. This technical solution can provide a larger deformation space for the slit 3031 while ensuring electrical performance, thereby improving the overall flexibility of the flexible printed circuit board 303. At the same time, a serpentine or zigzag stress release structure may be provided between the wires to further enhance flexibility.

[0062] In order to further improve the reliability of the flexible printed circuit board 303, a shielding layer can be added between the first wire layer and the second wire layer. This shielding layer can be made of a metal material (such as copper) and the thickness can be between 5μm and 20μm. The shielding layer can be connected to the ground wire in the first wire layer or the second wire layer through additional vias to form a complete electromagnetic shielding structure. This technical solution can effectively reduce electromagnetic interference and improve the quality and stability of signal transmission, and is particularly suitable for high-frequency signal transmission scenarios.

[0063] In order to enhance the durability of the flexible printed circuit board 303, an elastic buffer layer may be added between the first conductor layer and the second conductor layer. This buffer layer may be made of an elastic polymer material (such as polyurethane or silicone rubber) and may have a thickness between 20 μm and 100 μm. The buffer layer may be connected to the first conductor layer and the second conductor layer through elastic vias, which may provide additional deformation space when the flexible printed circuit board 303 is bent. This technical solution may effectively reduce stress concentration and extend the service life of the flexible printed circuit board 303, and is particularly suitable for application scenarios that require frequent bending.

[0064] The flexible printed circuit board 303 provided in the embodiment of the present application can be applied to flat and curved display devices. For a flat display device, the flexible printed circuit board 303 can be arranged in an L shape, such as Figure 4 and Figure 5 For a curved display device, the flexible printed circuit board 303 can be arranged in a long straight strip shape, such as Figure 6 , Figure 7 and Figure 8 shown.

[0065] In the embodiment of the present application, by providing a slit 3031 on the flexible printed circuit board 303, adaptive adjustment of the length of the flexible printed circuit board 303 is achieved. This technical solution enables the flexible printed circuit board 303 to adapt to positional deviations during the assembly process, effectively reducing the requirements for assembly accuracy, thereby improving the assembly yield of the display device and avoiding the problem of poor display caused by poor plug-in contact due to pulling after assembly or reliability testing. The embodiment of the present application can also alleviate the stress caused by factors such as material shrinkage, and improve the stability of the product during reliability testing and normal use. This technical solution enables the flexible printed circuit board 303 to adapt to slight deformations of the material, reduces changes in the plug-in distance caused by material shrinkage, and thus improves the long-term reliability of the display device. The embodiment of the present application reduces display anomalies caused by poor plug-in, ensures the stability of the electrical connection, and improves the overall quality and reliability of the liquid crystal display device.

[0066] The embodiment of the present application provides a display device and a flexible printed circuit board 303, which realizes adaptive adjustment of the length of the flexible printed circuit board 303. This technical solution has a high tolerance for the assembly fluctuation of the flexible printed circuit board 303, and can avoid poor electrical contact when the flexible printed circuit board 303 is plugged in, thereby avoiding poor display of the display device. At the same time, this technical solution can also avoid pulling on the flexible printed circuit board 303 due to characteristics such as material shrinkage during the reliability test, and avoid poor display after the reliability test.

[0067] In one embodiment, the flexible printed circuit board 303 provided in the embodiment of the present application is applied to a flat display device. In this case, the flexible printed circuit board 303 is L-shaped, such as Figure 4 and Figure 5 As shown. In the embodiment of the present application, a slit 3031 is provided on the L-shaped flexible printed circuit board 303 to realize the adaptive variable length of the flexible printed circuit board 303 in two directions. Specifically, a first slit 3031 parallel to one edge of the flexible printed circuit board 303 is provided to realize the adaptive variable length of the flexible printed circuit board 303 in one direction; and a second slit 3031 parallel to the other edge of the flexible printed circuit board 303 is provided to realize the adaptive variable length of the flexible printed circuit board 303 in another direction.

[0068] In another embodiment, the slit 3031 may be arranged at a certain angle (eg, 30 to 60 degrees) to the edge of the flexible printed circuit board 303, and the adaptive variable length of the flexible printed circuit board 303 in two directions may be achieved.

[0069] In another embodiment, the flexible printed circuit board 303 provided in the embodiment of the present application is applied to a curved display device. In this case, the flexible printed circuit board 303 is a long straight strip, such as Figure 6 , Figure 7 and Figure 8 As shown. A slit 3031 parallel to the length direction Y of the flexible printed circuit board 303 can be provided to achieve an adaptive variable length of the flexible printed circuit board 303 in the width direction X. A slit 3031 can also be provided at a certain angle (e.g., 30 to 60 degrees) to the length direction Y of the flexible printed circuit board 303 to achieve an adaptive variable length of the flexible printed circuit board 303 in both the length direction Y and the width direction X.

[0070] like Figures 4 to 8 As shown, in all embodiments, a through hole 3032 is provided on the flexible printed circuit board 303, and the through hole 3032 is connected to one end of the slit 3031. This technical solution can release stress and avoid tearing the flexible printed circuit board 303 due to stress concentration after receiving external force.

[0071] In order to solve the problem of reduced wiring space caused by the provision of the slit 3031 and the through hole 3032, the flexible printed circuit board 303 provided in the embodiment of the present application adopts a double-layer wiring design. Specifically, the flexible printed circuit board 303 includes a first wire layer and a second wire layer, and the film layer where the second wire layer is located is located above the film layer where the first wire layer is located. The two wire layers are electrically connected through a plurality of vias, and these vias are arranged on the side of the slit 3031 away from the edge of the flexible printed circuit board 303.

[0072] In a specific embodiment, the distance from one end of the slit 3031 (i.e., the end connected to the through hole 3032) to the nearest edge of the flexible printed circuit board 303 is greater than half the width of the flexible printed circuit board 303. This technical solution can ensure that the space occupied by the slit 3031 in the width direction X of the flexible printed circuit board 303 does not exceed half the width of the flexible printed circuit board 303, so that the arrangement of all metal traces can be completed by setting two layers of metal traces. If the space occupied by the slit 3031 exceeds half the width of the flexible printed circuit board 303, three or more layers of metal traces may need to be set.

[0073] Through the above technical solution, the embodiment of the present application realizes the adaptive length of the flexible printed circuit board 303 of the light bar of the backlight module, avoiding the problem of poor display caused by poor plugging contact due to pulling after assembly or reliability testing. This technical solution reduces the assembly defect rate, improves the reliability test pass rate, simplifies the assembly process, and improves production efficiency.

[0074] The embodiments of the present application are described in detail above, and the contents of this specification should not be construed as limiting the scope of protection of the present application.

Claims

1. A flexible printed circuit board, characterized in that: The flexible printed circuit board is provided with at least one slit, which penetrates the flexible printed circuit board in the thickness direction of the flexible printed circuit board, wherein a first end of the slit is located inside the flexible printed circuit board, and a second end of the slit is located at an edge of the flexible printed circuit board.

2. The flexible printed circuit board according to claim 1, wherein: The flexible printed circuit board is provided with a through hole communicating with the first end of the slit.

3. The flexible printed circuit board according to claim 1, wherein: A plurality of the slits are arranged in parallel.

4. The flexible printed circuit board according to claim 3, characterized in that: The second end of one of the two adjacent slits is located at one edge of the flexible printed circuit board, and the second end of the other of the two adjacent slits is located at the other edge of the flexible printed circuit board.

5. The flexible printed circuit board according to claim 1, wherein: At least one of the slits is perpendicular to an edge of the flexible printed circuit board.

6. The flexible printed circuit board according to claim 1, wherein: At least one of the slits forms an angle of 30 degrees to 60 degrees with an edge of the flexible printed circuit board.

7. The flexible printed circuit board according to claim 1, wherein: The plurality of slits include: at least one set of first slits parallel to an edge of the flexible printed circuit board; and at least one set of second slits parallel to another edge of the flexible printed circuit board; Wherein, the straight line where the first slit is located is perpendicular to the straight line where the second slit is located.

8. The flexible printed circuit board according to claim 1, wherein: The flexible printed circuit board comprises: a first conductor layer; a second conductive line layer, wherein the film layer where the second conductive line layer is located is located above the film layer where the first conductive line layer is located; and Multiple vias; The wires in the second wire layer are electrically connected to part of the wires in the first wire layer through the vias.

9. The flexible printed circuit board according to claim 8, characterized in that: The flexible printed circuit board comprises a first edge and a second edge opposite to each other, the second end of the slit is located at the second edge, and the distance from the first end of the slit to the first edge is greater than half of the distance between the first edge and the second edge of the flexible printed circuit board; The conductive lines in the second conductive line layer are located between the first end of the slit and the first edge of the flexible printed circuit board.

10. A display device, characterized in that: The display device comprises a printed circuit board assembly and the flexible printed circuit board according to any one of claims 1 to 9, the printed circuit board assembly comprises a connector, and the flexible printed circuit board is connected to the connector.

Images