Flexible display screen

Abstract

The invention discloses a flexible display screen which comprises a display area and a wiring area, the wiring area comprises a bending area and a binding area, and the binding area is located on the side, away from the display area, of the bending area and can be placed on the back face of the display area through bending of the bending area; the wiring area comprises a flexible substrate, a compressible insulating layer arranged on the front surface of the flexible substrate and a plurality of metal wires arranged on the front surface of the compressible insulating layer, and when the bending area is in a bending state, the compressible insulating layer can be compressed and deformed in the bending area along the thickness direction; therefore, the bending angle of each metal wire is smaller than the bending angle of the flexible substrate. According to the flexible display screen, the risk that wires are bent and broken can be reduced without changing an existing wiring structure.

Description

Technical Field

[0001] This invention relates to the field of flexible displays, and more particularly to a flexible display screen. Background Technology

[0002] In order to increase the screen-to-body ratio and achieve a full-screen display effect, existing flexible displays typically bend their wiring area to the back of the display area to reduce the bezel formed by the wiring area.

[0003] Due to bending stress, the trace area may break when bent. To reduce the risk of trace breakage, existing technologies generally reduce bending stress or block the transmission of bending stress by creating through-holes in the trace, using segmented and layered structures for the trace, or designing the trace as a wavy structure.

[0004] However, all of the above methods require changing the structure of the traces, which not only increases the number of steps and complexity of the trace etching process, but also increases the resistance of the traces to some extent, thereby affecting the conductivity of the traces. Summary of the Invention

[0005] To address the shortcomings of the prior art, this invention provides a flexible display screen that reduces the risk of bending and breakage of the wiring without altering the existing wiring structure.

[0006] The technical problem to be solved by the present invention is achieved through the following technical solution: A flexible display screen includes a display area and a wiring area. The wiring area includes a bending area and a bonding area. The bonding area is located on the side of the bending area away from the display area and can be placed on the back of the display area through bending in the bending area. The wiring area includes a flexible substrate, a compressible insulating layer disposed on the front side of the flexible substrate, and multiple metal traces disposed on the front side of the compressible insulating layer. When the bending area is in a bent state, the compressible insulating layer can be compressed and deformed along the thickness direction within the bending area, so that the bending angle of each metal trace is smaller than the bending angle of the flexible substrate.

[0007] Furthermore, the Young's modulus of the compressible insulating layer is less than that of the flexible substrate, and the Young's modulus of the flexible substrate is less than that of the metal trace.

[0008] Furthermore, the Young's modulus ratio between the compressible insulating layer and the flexible substrate is approximately between 1:10 and 1:50, and the Young's modulus ratio between the flexible substrate and the metal trace is approximately between 1:50 and 1:100.

[0009] Furthermore, the compressible insulation layer is preferably made of flexible polyurethane, silicone rubber, porous polyimide, or nanoporous elastomer.

[0010] Furthermore, when the bending radius of the flexible substrate is between 0.5 and 1.0 mm, the thickness of the compressible insulating layer is preferably between 0.5 and 1.5 μm; when the bending radius of the flexible substrate is between 1.0 and 2.0 mm, the thickness of the compressible insulating layer is preferably between 1.5 and 3.0 μm; and when the bending radius of the flexible substrate is between 2.0 and 5.0 mm, the thickness of the compressible insulating layer is preferably between 3.0 and 8.0 μm.

[0011] Furthermore, the display area also includes the flexible substrate, a pixel array layer disposed on the front side of the flexible substrate, and an encapsulation substrate disposed on the front side of the pixel array layer.

[0012] Furthermore, the compressible insulating layer is also disposed within the display area and is located between the flexible substrate and the pixel array layer.

[0013] Furthermore, the compressible insulating layer has a micropore array in the gap region between adjacent metal traces.

[0014] Furthermore, the porosity of the micropore array in the gap region between adjacent metal traces is between 20% and 40%, and the spacing between the micropore array and the metal traces on both sides is not less than 1 μm.

[0015] Furthermore, the micropores of the micropore array are arranged in an array lung-like manner along the tangential and axial directions of the bending region, and adjacent rows of micropores along the axial direction are staggered relative to each other along the tangential direction.

[0016] The present invention has the following beneficial effects: The flexible display screen of the present invention adds a compressible insulating layer between the flexible substrate in the wiring area and each metal trace. The compressible insulating layer has a small Young's modulus, and it can undergo compressive deformation when subjected to external force. When the bending area is in a bent state, each metal trace, when bent along with the bending area, has a springback tendency to return to its original shape, thereby forming a springback force applied to the compressible insulating layer along the thickness direction. Under the action of the springback force of each metal trace, the compressible insulating layer undergoes compressive deformation along the thickness direction. In the tangential direction of the fold, the resilience of each metal trace exhibits a distribution characteristic of being larger in the middle and smaller at both ends. Therefore, the thickness of the compressible insulating layer exhibits a structural characteristic of being smaller in the middle and larger at both ends. This results in the spacing between each metal trace and the flexible substrate also exhibiting a structural characteristic of being smaller in the middle and larger at both ends. Consequently, compared to the flexible substrate, each metal trace has a smaller bending angle, a gentler bending degree, and lower bending stress, thereby reducing the risk of bending and breakage of each metal trace. At the same time, there is no need to change the structure of each metal trace, thus ensuring the conductivity of each metal trace and simplifying the etching process. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the stacked structure of the flexible display screen provided by the present invention before bending.

[0018] Figure 2 This is a schematic diagram of the stacked structure of the flexible display screen provided by the present invention after bending.

[0019] Figure 3 This is a schematic diagram showing the distribution of various metal traces in the flexible display screen provided by the present invention.

[0020] Figure 4 This is a schematic diagram showing the distribution of the micro-hole array between the metal traces in the flexible display screen provided by the present invention.

[0021] Figure 5 This is a schematic diagram illustrating the shape, structure, and stress transmission of the micro-hole array in the flexible display screen provided by the present invention. Detailed Implementation

[0022] The present invention will now be described in detail with reference to the accompanying drawings and embodiments, examples of which are shown in the drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0023] In the description of this invention, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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 invention.

[0024] Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of that feature. In the description of this invention, "multiple" means two or more, unless otherwise explicitly specified.

[0025] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," and "setting," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0026] Example 1 like Figure 1-3 As shown, a flexible display screen includes a display area 10 and a wiring area 20. The wiring area 20 includes a bending area 201 and a bonding area 202. The bonding area 202 is located on the side of the bending area 201 away from the display area 10 and can be placed on the back of the display area 10 through the bending of the bending area 201. The wiring area 20 includes a flexible substrate 1, a compressible insulating layer 2 disposed on the front side of the flexible substrate 1, and multiple metal wirings 5 ​​disposed on the front side of the compressible insulating layer 2. When the bending area 201 is in a bent state, the compressible insulating layer 2 can be compressed and deformed along the thickness direction within the bending area 201, so that the bending angle Q of each metal wiring 5 is smaller than the bending angle P of the flexible substrate 1.

[0027] The flexible display screen of the present invention adds a compressible insulating layer 2 between the flexible substrate 1 and each metal trace 5 in the wiring area 20. The compressible insulating layer 2 has a small Young's modulus and can undergo compressive deformation when subjected to external force. When the bending area 201 is in a bent state, each metal trace 5 has a springback tendency to return to its original shape when bending together with the bending area 201, thereby forming a springback force applied to the compressible insulating layer 2 along the thickness direction. Under the action of the springback force of each metal trace 5, the compressible insulating layer 2 undergoes compressive deformation along the thickness direction. In the tangential direction Y, the resilience of each metal trace 5 exhibits a distribution characteristic of being larger in the middle and smaller at both ends. Therefore, the thickness of the compressible insulating layer 2 exhibits a structural characteristic of being smaller in the middle and larger at both ends. This results in the spacing between each metal trace 5 and the flexible substrate 1 also exhibiting a structural characteristic of being smaller in the middle and larger at both ends. Thus, compared to the flexible substrate 1, each metal trace 5 has a smaller bending angle, a gentler bending degree, and lower bending stress, thereby reducing the risk of bending and breakage of each metal trace 5. At the same time, there is no need to change the structure of each metal trace 5, so as to ensure the conductivity of each metal trace 5 and simplify the etching process.

[0028] In this embodiment, each metal trace 5 extends along the tangential direction Y of the bending area 201 and is arranged sequentially at intervals along the axial direction X of the bending area 201.

[0029] In some examples, the wiring area 20 also includes a non-bending area, which connects the display area 10 and the bending area 201. The non-bending area is also used to lay the various metal wirings 5. However, the non-bending area is not mandatory and can be omitted depending on the wiring requirements, bezel requirements, and assembly structure of the flexible display screen.

[0030] The Young's modulus of the compressible insulating layer 2 is less than that of the flexible substrate 1, and the Young's modulus of the flexible substrate 1 is less than that of the metal trace 5.

[0031] In this invention, the Young's modulus of the metal traces 5 is designed to be larger than that of the flexible substrate 1, in order to maximize the resilience of each metal trace 5 and the compression of the compressible insulating layer 2. The resilience force exerted by each metal trace 5 on the compressible insulating layer 2 can be transmitted and transformed into pressure exerted by the compressible insulating layer 2 on the flexible substrate 1. By designing the Young's modulus of the flexible substrate 1 to be larger than that of the compressible insulating layer 2, it is ensured that the flexible substrate 1 will not collapse under the pressure of the compressible insulating layer 2, thereby supporting the arc-shaped structure of the bending region 201.

[0032] Preferably, the Young's modulus ratio between the compressible insulating layer 2 and the flexible substrate 1 is approximately between 1:10 and 1:50, and the Young's modulus ratio between the flexible substrate 1 and the metal trace 5 is approximately between 1:50 and 1:100.

[0033] The flexible substrate 1 may be, but is not limited to, a polyimide film or a polyester film, with a thickness between 10 and 50 μm; the metal trace 5 may be, but is not limited to, a copper trace, a silver trace, a molybdenum trace, a gold trace, or a composite trace containing the aforementioned metal trace 5, with a thickness between - and 35 μm.

[0034] The compressible insulating layer 2 should preferably be made of a material with a low Young's modulus, and may include, but is not limited to, flexible polyurethane, silicone rubber, porous polyimide, or nanoporous elastomers. Depending on the bending radius of the flexible substrate 1, the compressible insulating layer 2 may have different thicknesses to match it. When the bending radius of the flexible substrate 1 is between 0.5 and 1.0 mm, the thickness of the compressible insulating layer 2 is preferably between 0.5 and 1.5 μm; when the bending radius of the flexible substrate 1 is between 1.0 and 2.0 mm, the thickness of the compressible insulating layer 2 is preferably between 1.5 and 3.0 μm; and when the bending radius of the flexible substrate 1 is between 2.0 and 5.0 mm, the thickness of the compressible insulating layer 2 is preferably between 3.0 and 8.0 μm.

[0035] The display area 10 also includes the flexible substrate 1, a pixel array layer 3 disposed on the front side of the flexible substrate 1, and an encapsulation substrate 4 disposed on the front side of the pixel array layer 3. Preferably, the compressible insulating layer 2 is also disposed within the display area 10 and located between the flexible substrate 1 and the pixel array layer 3 to avoid a height difference between the pixel array layer 3 and each metal trace 5.

[0036] The encapsulation substrate 4 can be a rigid substrate, such as a glass substrate, or another flexible substrate 1, depending on whether the display area 10 needs to be bent.

[0037] Example 2 When the compressible insulating layer 2 is compressed and deformed, the internal materials will squeeze against each other, resulting in stress. This stress causes interlaminar shear force between the compressible insulating layer 2 and each metal trace 5. Since the length of the metal trace 5 is relatively large and the length of the bending region 201 is relatively small, the longitudinal shear force generated by the compressible insulating layer 2 along the tangential direction Y of the bending region 201 (i.e., the extension direction of the metal trace 5) is small and can be evenly distributed along the extension direction of the metal trace 5, having little impact on the metal trace 5. However, the width of the metal trace 5 is small, and the width of the bending region 201 is relatively large. The transverse shear force generated by the compressible insulating layer 2 along the axial direction X of the bending region 201 (i.e., the width direction of the metal trace 5) is large and too concentrated in the width direction of the metal trace 5, easily leading to breakage of the metal trace 5.

[0038] As an optimization of Embodiment 1, in this embodiment, such as Figure 2 As shown, the compressible insulating layer 2 has a micropore array 21 in the gap area between adjacent metal traces 5.

[0039] The flexible display of the present invention has a micro-hole array 21 formed in the compressible insulating layer 2, so as to use a series of tiny micro-holes 211 in the micro-hole array 21 to accommodate the internal materials of the compressible insulating layer 2 that are squeezed against each other during compression deformation, thereby reducing the stress generated by the compressible insulating layer 2. Furthermore, by placing the micro-hole array 21 between adjacent metal traces 5, the lateral stress transmission of the compressible insulating layer 2 between adjacent metal traces 5 can be partially blocked, so that each metal trace 5 is not affected by the stress of the compressible insulating layer 2 below other metal traces 5, thereby reducing the risk of breakage of each metal trace 5.

[0040] The micro-hole array 21 does not completely disconnect the compressible insulating layer 2 below the adjacent metal traces 5. Instead, it retains a partial connection between the compressible insulating layer 2 below the adjacent metal traces 5 through the hole walls between each micro-hole 211, so as to play a certain lateral limiting role and avoid excessive lateral displacement of the compressible insulating layer 2 below the adjacent metal traces 5 during compression deformation, thereby causing short circuit problems of the adjacent metal traces 5.

[0041] Preferably, the porosity of the micropore array 21 in the gap region between adjacent metal traces 5 is between 20% and 40%, and the spacing between it and the metal traces 5 on both sides is not less than 1 μm.

[0042] like Figure 5As shown, the tiny micropores 211 in the micropore array 21 can be, but are not limited to, circular pores, triangular pores, prismatic pores or hexagonal pores, etc., with a diameter or side length between 1-3 μm, a center-to-center spacing between 1.5-3 μm, and a depth between 0.5-8 μm.

[0043] The micropores 211 of the micropore array 21 are arranged in an array lung-like manner along the tangential direction Y and the axial direction X of the bending region 201, and the two adjacent rows of micropores 211 along the axial direction X are staggered relative to each other along the tangential direction Y.

[0044] The micropores 211 in the micropore array 21 are staggered along the tangent direction Y of the bending region 201, so that four adjacent micropores 211 in the upper, lower, left and right directions can form a micropore 211 unit. There is a meeting point between the walls of the four micropores 211 in the same micropore 211 unit. When the lateral stress generated by the compressible insulating layer 2 passes through this meeting point, it first converges and then disperses, and is partially offset and gradually reduced, so as to further reduce the lateral stress transmission of the compressible insulating layer 2 between adjacent metal traces 5.

[0045] Assuming the lateral stress is transmitted from left to right within the micropore array 21, the first lateral stress f1 entering from the hole wall between the left micropore 211 and the upper micropore 211 can be decomposed into component stresses along the tangential direction Y and the axial direction X. Similarly, the second lateral stress f2 entering from the hole wall between the left micropore 211 and the lower micropore 211 can also be decomposed into component stresses along the tangential direction Y and the axial direction X. The component stress of the first lateral stress f1 along the tangential direction Y and the component stress of the second lateral stress f2 along the tangential direction Y are opposite in direction and can cancel each other out. Therefore, the first lateral stress f1 and the second lateral stress f2 will decrease when they converge at the intersection point, and then decompose into the third lateral stress f3 and the fourth lateral stress f4, which exit from the hole walls between the right micropore 211 and the upper micropore 211, and between the right micropore 211 and the lower micropore 211, respectively, and become the first lateral stress f1 and the second lateral stress f2 of the next level micropore 211 unit, ultimately achieving a step-by-step reduction and cancellation.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention and not to limit them. Although the embodiments of the present invention have been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the embodiments of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A flexible display screen, comprising a display area and a wiring area, the wiring area including a bending area and a bonding area, the bonding area being located on the side of the bending area away from the display area, and being able to be placed on the back of the display area through bending in the bending area; characterized in that, The routing area includes a flexible substrate, a compressible insulating layer disposed on the front side of the flexible substrate, and multiple metal traces disposed on the front side of the compressible insulating layer. When the bending area is in a bent state, the compressible insulating layer can be compressed and deformed along the thickness direction within the bending area, so that the bending angle of each metal trace is smaller than the bending angle of the flexible substrate.

2. The flexible display screen according to claim 1, characterized in that, The Young's modulus of the compressible insulating layer is less than that of the flexible substrate, and the Young's modulus of the flexible substrate is less than that of the metal trace.

3. The flexible display screen according to claim 1 or 2, characterized in that, The Young's modulus ratio between the compressible insulating layer and the flexible substrate is approximately between 1:10 and 1:50, and the Young's modulus ratio between the flexible substrate and the metal trace is approximately between 1:50 and 1:

100.

4. The flexible display screen according to claim 1, characterized in that, The compressible insulation layer should preferably be made of flexible polyurethane, silicone rubber, porous polyimide, or nanoporous elastomer.

5. The flexible display screen according to claim 1 or 4, characterized in that, When the bending radius of the flexible substrate is between 0.5 and 1.0 mm, the thickness of the compressible insulating layer is preferably between 0.5 and 1.5 μm; when the bending radius of the flexible substrate is between 1.0 and 2.0 mm, the thickness of the compressible insulating layer is preferably between 1.5 and 3.0 μm; and when the bending radius of the flexible substrate is between 2.0 and 5.0 mm, the thickness of the compressible insulating layer is preferably between 3.0 and 8.0 μm.

6. The flexible display screen according to claim 1, characterized in that, The display area also includes the flexible substrate, a pixel array layer disposed on the front side of the flexible substrate, and an encapsulation substrate disposed on the front side of the pixel array layer.

7. The flexible display screen according to claim 6, characterized in that, The compressible insulating layer is also disposed within the display area and is located between the flexible substrate and the pixel array layer.

8. The flexible display screen according to claim 1, characterized in that, The compressible insulating layer has a micropore array in the gap region between adjacent metal traces.

9. The flexible display screen according to claim 8, characterized in that, The porosity of the micropore array in the gap region between adjacent metal traces is between 20% and 40%, and the spacing between the micropore array and the metal traces on both sides is not less than 1 μm.

10. The flexible display screen according to claim 8, characterized in that, The micropores in the micropore array are arranged in an array lung-like manner along the tangential and axial directions of the bending region, and adjacent rows of micropores along the axial direction are staggered relative to each other along the tangential direction.

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