Display device

Abstract

The embodiment of the invention discloses a display device. The display device comprises a display panel and an anti-impact layer, the anti-impact layer comprises at least two sub-layers, every two adjacent sub-layers are bonded through a bonding layer, the at least two sub-layers comprise a first sub-layer and a second sub-layer between the first sub-layer and the display panel, and the ratio of the elastic modulus of the first sub-layer to the elastic modulus of the second sub-layer is 20-300. The material of the first sub-layer is different from that of the second sub-layer; the display panel is provided with the anti-impact layer at least comprising the high elastic modulus layer and the low elastic modulus layer, when the display device is impacted, impact energy is spread in a transverse mode and a longitudinal mode in the form of stress waves, the transverse stress waves are spread in the plane of the first sub-layer rapidly, and the stress waves are spread in the plane of the second sub-layer rapidly. The first sub-layer can rapidly absorb stress waves in the horizontal direction through small strain, the second sub-layer can absorb impact energy more easily through large deformation, and longitudinal stress waves can be reflected back to the first sub-layer more easily.

Description

[0001] This application is a divisional application. The original application has the application number 202310331643.3 and the original application date is March 30, 2023. The entire contents of the original application are incorporated herein by reference. Technical Field

[0002] This application relates to the field of displays, and more specifically to a display device. Background Technology

[0003] The lifespan and durability of a display device are important parameters of product quality. If the outermost protective cover of the display device cannot withstand the impact, especially for outward-folding display devices, the display panel is closer to the outside world and is more susceptible to impacts from foreign objects. Impacts such as bumps and drops test the lifespan of the display device.

[0004] Therefore, there is an urgent need for a display device to solve the above-mentioned technical problems. Summary of the Invention

[0005] This application provides a display device that can improve the impact resistance of current display devices.

[0006] This application provides a display device, including: Display panel; An impact-resistant layer is disposed on the light-emitting side of the display panel; The impact-resistant layer includes at least two sub-layers, which are bonded together by an adhesive layer. The at least two sub-layers include a first sub-layer and a second sub-layer located on the side of the first sub-layer closer to the display panel. The ratio of the elastic modulus of the first sub-layer to the elastic modulus of the second sub-layer is 20 to 300. The material of the first sub-layer is different from that of the second sub-layer.

[0007] In some embodiments, the strain rate of the second sublayer is less than or equal to 100 s⁻¹.

[0008] In some embodiments, the second sublayer comprises any one of polyurethane, toluene diisocyanate, polydimethylsiloxane, cyclomethylsiloxane, aminosiloxane, polymethylphenylsiloxane, and polyether polysiloxane copolymer.

[0009] In some embodiments, the thickness of the second sub-layer is greater than the thickness of the first sub-layer.

[0010] In some embodiments, the display device includes a bending region and planar regions located on both sides of the bending region; the second sub-layer includes a first portion disposed within the bending region and a second portion disposed within the planar regions; wherein the elastic modulus of the first portion is less than the elastic modulus of the second portion.

[0011] In some embodiments, the impact-resistant layer further includes a third sublayer located on the side of the second sublayer away from the first sublayer, and the ratio of the elastic modulus of the third sublayer to the elastic modulus of the second sublayer is 20 to 300.

[0012] In some embodiments, the thickness of the third sublayer is less than or equal to the thickness of the first sublayer.

[0013] In some embodiments, the thickness of the third sublayer is less than the thickness of the second sublayer.

[0014] In some embodiments, the first sublayer or the third sublayer comprises any one of polyimide, polyethylene terephthalate, or acrylic.

[0015] In some embodiments, the impact-resistant layer further includes a fourth sub-layer and a fifth sub-layer, wherein the fourth sub-layer is located on the side of the third sub-layer away from the first sub-layer, and the fifth sub-layer is located on the side of the fourth sub-layer away from the first sub-layer; wherein the elastic modulus of the fifth sub-layer is greater than the elastic modulus of the fourth sub-layer, and the elastic modulus of the third sub-layer is greater than the elastic modulus of the fourth sub-layer.

[0016] In some embodiments, the ratio of the elastic modulus of the fifth sublayer to the elastic modulus of the fourth sublayer is 20 to 300, and the ratio of the elastic modulus of the third sublayer to the elastic modulus of the fourth sublayer is 20 to 300.

[0017] In some embodiments, the elastic modulus of the fifth sublayer is greater than that of the first sublayer, and the elastic modulus of the fifth sublayer is greater than that of the third sublayer.

[0018] In some embodiments, the sum of the thickness of the third sublayer and the thickness of the fifth sublayer is less than or equal to the thickness of the first sublayer.

[0019] In some embodiments, the thickness of the fourth sub-layer is greater than the thickness of the third sub-layer, and the thickness of the fourth sub-layer is greater than the thickness of the fifth sub-layer.

[0020] In some embodiments, the thickness of the fourth sublayer is less than the thickness of the second sublayer.

[0021] In some embodiments, the display device includes a bending region and planar regions located on both sides of the bending region; the fourth sub-layer includes a third portion disposed within the bending region and a fourth portion disposed within the planar regions; wherein the elastic modulus of the third portion is less than the elastic modulus of the fourth portion.

[0022] In some embodiments, the strain rate of the fourth sublayer is less than or equal to 100 s⁻¹.

[0023] The fourth sublayer comprises any one of the following materials: polyurethane, toluene diisocyanate, polydimethylsiloxane, cyclomethylsiloxane, aminosiloxane, polymethylphenylsiloxane, and polyether polysiloxane copolymer; the fifth sublayer comprises any one of the following materials: polyimide, polyethylene terephthalate, and acrylic.

[0024] In some embodiments, the first sub-layer includes a first layer and a second layer, wherein the second layer is located on the side of the first layer closer to the display panel; wherein the hardness of the first layer is greater than the hardness of the second layer.

[0025] The beneficial effects of this application are as follows: By setting an impact-resistant layer comprising at least two elastic modulus layers (high and low) on the display panel, when the display device is impacted, the impact energy propagates as stress waves in both lateral and longitudinal directions. The stress waves first contact the high elastic modulus film layer. The lateral stress waves propagate rapidly within the surface of the first sub-layer, which can quickly absorb the horizontal stress waves with relatively small strain. The longitudinal stress waves continue to propagate inward in a direction perpendicular to the display device. When they contact the second sub-layer with the low elastic modulus, the second sub-layer is more likely to absorb the impact energy through larger deformation. At the same time, the stress waves are more likely to propagate in the film layer with the high modulus. Since the elastic modulus difference between the second and first sub-layers is large, the longitudinal stress waves are more likely to be reflected back to the first sub-layer, slowing down the tendency of the longitudinal stress waves to propagate further inward in a direction perpendicular to the display device. This is more conducive to protecting the display panel and extending the service life of the display device. Attached Figure Description

[0026] 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 only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the first structure of the display device provided in the embodiments of this application; Figure 2 This is a schematic diagram of the second structure of the display device provided in the embodiments of this application; Figure 3 This is a schematic diagram of the overall structure of the ball drop test of the display device provided in the embodiments of this application; Figure 4 This is a schematic diagram of the propagation of the impact stress wave in the drop ball test of the display device provided in this application embodiment within two different materials; Figure 5 This is a schematic diagram of the propagation of the impact stress wave of a falling ball during a falling ball test of the display device provided in this application within different stacked designs; Figure 6 This is a schematic diagram of the test point arrangement for the ball drop test of the display device provided in the embodiments of this application; Figure 7 This is a schematic diagram of the impact mechanics simulation of a falling ball during a ball drop test of the display device provided in this application embodiment; Figure 8 This is a schematic diagram showing the propagation of stress waves in two different directions inside the display device during a ball drop test provided in this application embodiment; Figure 9 This is a partial structural diagram of the bending area of ​​the display device provided in the embodiments of this application. Detailed Implementation

[0028] 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 skilled in the art without creative effort are within the scope of protection of this application. In addition, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application. In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0029] The lifespan and durability of a display device are important parameters of product quality. If the outermost protective cover of the display device cannot withstand the impact, especially for outward-folding display devices, the display panel is closer to the outside world and is more susceptible to impacts from foreign objects. Impacts such as bumps and drops test the lifespan of the display device.

[0030] Please see Figures 1 to 9 This invention provides a display device 100, comprising: Display panel 200; An impact-resistant layer 300 is disposed on the light-emitting side of the display panel 200; The impact-resistant layer 300 includes at least two sub-layers, and adjacent sub-layers are bonded together by an adhesive layer 400. The at least two sub-layers include a first sub-layer 310 and a second sub-layer 320 located on the side of the first sub-layer 310 closer to the display panel 200. The ratio of the elastic modulus of the first sub-layer 310 to the elastic modulus of the second sub-layer 320 is 20 to 300. The material of the first sub-layer 310 is different from that of the second sub-layer 320.

[0031] This application provides an impact-resistant layer on the display panel, comprising at least two elastic modulus layers: a high-modulus layer and a low-modulus layer. When the display device is impacted, the impact energy propagates as stress waves in both lateral and longitudinal directions. The stress waves first contact the high elastic modulus film layer. The lateral stress waves propagate rapidly within the surface of the first sub-layer, which can quickly absorb the lateral stress waves with relatively small strain. The longitudinal stress waves continue to propagate inward in a direction perpendicular to the display device. When they contact the second sub-layer, which is a low elastic modulus layer, the second sub-layer is more likely to absorb the impact energy through greater deformation. Simultaneously, the stress waves propagate more easily in the high-modulus film layer. Because the elastic modulus difference between the second and first sub-layers is larger, the longitudinal stress waves are more easily reflected back to the first sub-layer, slowing down the tendency of the longitudinal stress waves to propagate further inward in a direction perpendicular to the display device. This is more beneficial for protecting the display panel and extending the service life of the display device.

[0032] The technical solution of this application will now be described in conjunction with specific embodiments.

[0033] In some embodiments, please refer to Figure 1 The impact-resistant layer 300 further includes an adhesive layer 400 disposed between two adjacent sublayers. For example, see [link to relevant documentation]. Figure 1 The impact-resistant layer 300 further includes a first adhesive layer 410 disposed between the first sub-layer 310 and the second sub-layer 320, and a second adhesive layer 420 disposed between the second sub-layer 320 and the third sub-layer 330. The adhesive layer 400 may be an optical adhesive layer.

[0034] Simply increasing the thickness of the impact-resistant layer 300 can improve the impact resistance, but it will cause the overall neutral layer of the display device 100 to shift. Therefore, in order to make the neutral layer closer to the display panel 200, a thicker film layer needs to be provided on the backlight side of the display panel 200, which will increase the overall thickness of the display device 100. On the one hand, this is not conducive to making the display device 100 thinner and lighter. On the other hand, for a foldable display device 100, a larger thickness of the display device 100 is also not conducive to the bending of the display device 100.

[0035] Please see Figure 1 , 4When the display device 100 is subjected to an external impact load or instantaneous impact, the outermost layer is impacted first. The impact energy propagates within the material layer in the form of stress waves, that is, it propagates along the horizontal transverse (in-plane) and longitudinal (perpendicular to the thickness direction) of the film layer, including transverse stress waves and longitudinal stress waves.

[0036] Please see Figure 3 The first sub-layer 310 at the top has a high modulus, and the transverse stress wave propagates rapidly in the plane. Compared with the thickness direction, the transverse material area of ​​the first sub-layer 310 is larger, and it can quickly absorb the transverse stress wave with a small strain. That is, the transverse impact stress wave releases or diffuses the stress to the far end of the impact area as the layer vibrates and deforms.

[0037] Please see Figure 3 , Figure 5 The longitudinal stress wave continues to propagate along the thickness direction of the display device 100. Since the second sub-layer 320 has a lower modulus, it is easier to absorb the impact energy through larger deformation, thus reducing the tendency of the longitudinal stress wave to propagate further along the thickness direction.

[0038] Please see Figure 4 When a stress wave enters the low-modulus layer (second sublayer 320) from the high-modulus material layer (first sublayer 310), due to the different impedance characteristics of the two materials (similar to the light propagation characteristics of glass and water), reflection and transmission phenomena will occur at the adjacent interface. That is, the difference in stress wave propagation near the two film layers. The greater the difference in impedance between the two materials, the stronger the reflected wave, and the less stress wave is transmitted into the low-modulus layer, while more stress waves return in the opposite direction.

[0039] Please see Figure 5 The wave impedance is proportional to the material density and wave velocity, while the wave velocity is positively correlated with the material's modulus. Stress waves are more likely to propagate in films with high modulus. Since the elastic modulus of the second sublayer 320 is much larger than that of the first sublayer 310, longitudinal stress waves are more likely to be reflected back to the first sublayer 310. In the figure, I represents stress wave, R represents reflected wave, and T represents transmitted wave.

[0040] If the difference between the elastic modulus of the second sub-layer 320 and the elastic modulus of the first sub-layer 310 is too small, it will not be conducive to the reflection of longitudinal stress waves back to the first sub-layer 310 to protect the display panel 200, and will cause more longitudinal stress waves to penetrate into the display device 100. If the difference between the elastic modulus of the second sub-layer 320 and the elastic modulus of the first sub-layer 310 is too large, that is, the elastic modulus of the second sub-layer 320 is too small, such as some adhesive layer OCA glue, the elastic modulus is in the Kpa level, and its own unique viscous flow characteristics make it difficult to disperse and absorb impact energy through in-plane vibration when subjected to impact.

[0041] By providing an impact-resistant layer 300 comprising at least two elastic modulus layers (high and low) on the display panel 200, two main lines of defense against impact are formed, extending the service life of the display device 100. At the same time, for the foldable display device 100, the elastic modulus of the second sub-layer 320 is relatively small, which is beneficial for the bending of the display device 100.

[0042] Among them, the elastic modulus is independent of humidity, and the elastic modulus of the material does not change significantly at room temperature (20℃ to 35℃). Therefore, the elastic modulus limits in this paper are all limited to the room temperature (20℃ to 35℃).

[0043] In some embodiments, please refer to Figure 3 The display panel 200 includes a panel body 210, an encapsulation layer 220, and a touch layer 230.

[0044] Please see Figure 2 , Figure 6 , Figure 7 , Figure 9 Taking the foldable display device 100 as an example, a drop ball test was conducted. The test of the impact height of the drop ball 110 was carried out in accordance with the GB15763.2-2005 standard. The drop ball 110 was a steel ball with a diameter of 20mm and a weight of 32g. Nine measurement points were selected at the same interval between the bending area 101 and the flat area 102 of the screen body. Through simulation and referring to the actual drop ball 110 impact test, the finite element simulation method was used. Combined with the stress behavior of the display device 100 under impact load, the encapsulation layer 220 in the display panel 200 was used as the failure judgment point. According to the failure mechanism of the encapsulation layer 220, the finite element analysis method was used, with the maximum tensile strain of the encapsulation layer 220 as the reference basis, to verify and compare the differences and advantages and disadvantages of the stacked design of the impact-resistant display device 100.

[0045] Please see Figure 8 Based on the aforementioned principle of impact stress wave propagation and through simulation experiments, it can be seen that when the impact-resistant layer 300 is subjected to the impact of a falling ball 110 or a foreign object, the stress wave first enters the first sub-layer 310 and decomposes into stress waves in two directions: horizontal (in-plane) and longitudinal (perpendicular to the thickness direction). Figure 8 In Figure (a), the transverse (X direction) stress is tensile stress, where Figure 8 In Figure (b), the longitudinal (Y direction) is the compressive wave stress, and the transverse stress wave is gradually dissipated through the vibration and deformation of the high elastic modulus material; the longitudinal stress wave is gradually dissipated through the absorption and blocking effect of the deformation of the low elastic modulus material, thus avoiding excessive stress wave transmission to the display panel 200.

[0046] Simulation experiments were conducted for the control group and experimental groups 1-10. The elastic modulus of CPI (transparent polyimide) was 3500 MPa, that of PET (polyethylene terephthalate) was 3500 MPa, that of UTG (ultra-thin glass) was 70000 MPa, that of TPU (thermoplastic polyurethane elastomer rubber) was 200 MPa, and that of PDMS (polydimethylsiloxane) was 20 MPa. Specific simulation conditions and results are shown in Table 1.

[0047] Table 1

[0048] The simulation results show that, comparing the high-high elastic modulus double-layer impact-resistant layer 300 in the control group with the high-high elastic modulus double-layer impact-resistant layer 300 in experimental groups 1-4, if the second sub-layer 320 still maintains a high elastic modulus, the reduction effect on the tensile strain (TFE Tensile strain) of the encapsulation layer 220 of the display panel 200 is not significant. Moreover, the tensile strain results of all five groups of experiments are above 0.8%, which exceeds the failure limit value of the inorganic layer in the encapsulation layer 220. That is, the high-high elastic modulus double-layer structure cannot effectively reduce the intensity of longitudinally transmitted stress waves.

[0049] For the high-low elastic modulus double-layer impact-resistant layer 300 in experimental groups 5 and 6, the elastic modulus of the first sub-layer is greater than that of the second sub-layer. Reducing the elastic modulus of the second sub-layer 320 has a significant effect on reducing the tensile strain of the encapsulation layer of the display panel 200. This indicates that using the high-low elastic modulus double-layer impact-resistant layer 300 is beneficial for reducing impact stress.

[0050] Comparing experimental groups 5, 6, and 7, increasing the thickness of low-modulus materials does not significantly contribute to reducing stress wave intensity; therefore, thickness is not the main influencing factor on reducing stress wave intensity. Furthermore, excessive thickness affects bending characteristics.

[0051] In some embodiments, the elastic modulus of the first sublayer is greater than that of the second sublayer, and the ratio of the elastic modulus of the first sublayer to the elastic modulus of the second sublayer is 20 to 300.

[0052] If the difference between the elastic modulus of the second sub-layer 320 and the elastic modulus of the first sub-layer 310 is too small, the elastic modulus of the second sub-layer will be too large. This will not be conducive to the reflection of longitudinal stress waves back to the first sub-layer 310 to protect the display panel 200, and will cause more longitudinal stress waves to penetrate deeper into the display device 100. If the difference between the elastic modulus of the second sub-layer 320 and the elastic modulus of the first sub-layer 310 is too large, that is, the elastic modulus of the second sub-layer 320 is too small, such as some adhesive layers like OCA adhesive, which has an elastic modulus in the Kpa range, its own unique adhesive properties will be too small. The fluidity characteristics make it difficult to disperse and absorb impact energy through in-plane vibration when subjected to impact; the ratio of the elastic modulus of the first sub-layer 310 to the elastic modulus of the second sub-layer 320 is 20 to 300, for example, the ratio of the static elastic modulus of the first sub-layer 310 to the static elastic modulus of the second sub-layer 320 is 20 to 300, for example, any one of the ratios of 20, 50, 80, 100, 150, 200, 240, 250, 280, and 300.

[0053] In some embodiments, the strain rate of the second sublayer 320 is less than or equal to 100 s⁻¹. -1 .

[0054] The greater the strain rate, the greater the increase in the elastic modulus of the film when it is subjected to impact. If the elastic modulus of the film increases significantly when it is subjected to impact, such as the OCA adhesive layer, the material itself is a high molecular weight adhesive material, which is prone to modulus enhancement under different impact intensities. That is, the greater the impact intensity, the stronger its viscoelastic effect, which is macroscopically manifested as an increase in instantaneous modulus, leading to insufficient resistance to longitudinal stress waves.

[0055] The material of the second sub-layer 320 can be a stress rate (strain rate) independent layer material or a low stress (strain rate) material, that is, under the action of impact load, the modulus of this layer material does not increase or the strength increases with the change of impact intensity; the material of this layer can maintain the stability and uniformity of modulus under impact load; or, the modulus of this layer material decreases with the increase of impact intensity under impact load, thereby ensuring that the elastic modulus of the second sub-layer 320 does not increase significantly when the display device 100 is subjected to strong impact, avoiding a significant weakening of the ability of the second sub-layer 320 to absorb longitudinal stress waves, ensuring the absorption of longitudinal stress waves, and helping to hinder the propagation of stress waves.

[0056] Methods for measuring strain rate in a series of experiments studying the dynamic mechanical properties of materials include: pendulum test (e.g., strain rate 10E0~10E2 / s), Hopkinson test (e.g., strain rate 10E2~10E4 / s), and air gun test (e.g., strain rate 10E4~10E6 / s). These are just examples and not specific limitations.

[0057] Comparing experimental groups 5 and 8, for laminated materials of the same thickness, the strain of the encapsulation layer decreased to about 0.5% when using strain rate-independent material PDMS (polydimethylsiloxane) compared to strain rate-increasing material TPU (thermoplastic polyurethane elastomer rubber). This indicates that using stress rate-independent or low stress rate material as the second sublayer 320 is more beneficial for reducing impact stress.

[0058] In some embodiments, optionally, the strain rate of the second sublayer 320 is 10 s. -1 ~100s -1 .

[0059] In some embodiments, the material of the second sublayer 320 may be selected from any one of polyurethane, toluene diisocyanate, polydimethylsiloxane, cyclomethylsiloxane, aminosiloxane, polymethylphenylsiloxane, polyether polysiloxane copolymer, etc.; such materials are stress rate (strain rate) independent layer materials or low stress (strain rate) rate materials, that is, under impact load, the modulus of this layer material does not increase or the strength increases with the change of impact strength; such materials can also be modified to have better chemical stability, electrical insulation, weather resistance and hydrophobicity, and have high shear resistance, and can be used for a long time at -50℃ to 200℃; at the same time, they have excellent physical properties, such as moisture-proof insulation, damping and shock absorption performance.

[0060] For example, an optically transparent elastomer material produced by coupling the active groups of macromolecular polydimethylsiloxane with a curing agent has a light transmittance of more than 93%, a refractive index of more than 1.4%, high dielectric properties, good elasticity, and an elongation of more than 500%.

[0061] In some embodiments, the first sublayer 310 may include any one of the following materials: polyimide, CPI (transparent polyimide), PET (polyethylene terephthalate), and acrylic polymers with high elastic modulus. Such materials have a high elastic modulus, which is beneficial for forming a high-low elastic modulus film layer with the second sublayer 320. Vibration wave reflection and transmission occur at the interface. Due to the difference in stress wave propagation near the two film layers, the greater the impedance difference between the two materials, the stronger the reflected wave, resulting in less stress wave transmission into the low-modulus layer and more stress wave returning in the opposite direction.

[0062] In some embodiments, please refer to Figure 2 The first sub-layer 310 includes a first layer 311 and a second layer 312, with the second layer 312 located on the side of the first layer 311 closer to the display panel 200; wherein the hardness of the first layer 311 is greater than that of the second layer 312.

[0063] The first sub-layer 310, as the outermost layer of the display device 100, needs to have better wear and scratch resistance. Therefore, a polymer hardening layer can be provided on the second layer 312. The thickness of the first layer 311 is 2μm to 5μm. The first layer 311 can be a coating material, such as polyurethane, so that the first sub-layer 310 has high modulus characteristics to resist impact stress, while also having anti-scratch and wear characteristics, further extending the service life of the display device 100.

[0064] In some embodiments, the first layer 311 has a Mohs hardness of 6 to 7.

[0065] In some embodiments, please refer to Figure 1 The thickness of the second sub-layer 320 is greater than that of the first sub-layer 310. The second sub-layer 320 has a lower elastic modulus, which is more conducive to absorbing longitudinal stress waves. Setting the thickness of the second sub-layer 320 to be thicker can more fully absorb longitudinal stress waves, reduce the energy of longitudinal stress waves passing through the second sub-layer 320, ensure the absorption of longitudinal stress waves, and help to hinder the propagation of stress waves, thus extending the service life of the display device 100.

[0066] In some embodiments, the thickness of the first sublayer 310 is 50 μm to 80 μm, and the thickness of the second sublayer 320 is 100 μm to 200 μm. The elastic modulus of the first sublayer 310 is 2000 MPa to 6000 MPa, and the elastic modulus of the second sublayer 320 is 20 MPa to 100 MPa. The thickness can be adaptively adjusted according to the actual situation, such as when the display device 100 has a foldable structure, based on the radius of the folding angle of the display device 100.

[0067] In some embodiments, please refer to Figure 2 The display device 100 includes a bending region 101 and a planar region 102 located on both sides of the bending region 101; the second sub-layer 320 includes a first portion 321 disposed in the bending region 101 and a second portion 322 disposed in the planar region 102; wherein the elastic modulus of the first portion 321 is less than the elastic modulus of the second portion 322.

[0068] The display device 100 has a bendable structure, and the bending area 101 needs to have better bending performance. The second sub-layer 320 is a low elastic modulus film layer. While ensuring the impact resistance of the bending area 101, it can optimize the bending performance of the bending area 101 by further reducing the elastic modulus of the first part 321 in the bending area 101, thereby improving the bending performance of the bending area 101, reducing the risk of damage to the display panel 200 in the bending area 101 by bending stress, and extending the service life of the display device 100.

[0069] In some embodiments, the first portion 321 and the second portion 322 may be integrally formed or separate components. If the first portion 321 and the second portion 322 are integrally formed, the elastic modulus can be adjusted by modifying the process conditions during the formation of the first portion 321 and the second portion 322, such as curing temperature and curing rate, so that the elastic modulus of the first portion 321 is smaller than that of the second portion 322.

[0070] In some embodiments, please refer to Figure 1 , Figure 2 The impact-resistant layer 300 further includes a third sub-layer 330, which is located on the side of the second sub-layer 320 away from the first sub-layer 310, and the elastic modulus of the third sub-layer 330 is greater than that of the second sub-layer 320.

[0071] The elastic modulus of the third sub-layer 330 is greater than that of the second sub-layer 320. The first sub-layer 310, the second sub-layer 320, and the third sub-layer 330 form a high-low-high elastic modulus structure. As a film layer with a high elastic modulus, the third sub-layer 330 is more conducive to absorbing stress waves passing through the second sub-layer 320. As the third main line of defense against impact, it is more conducive to extending the service life of the display device 100.

[0072] In some embodiments, the ratio of the elastic modulus of the third sublayer to the elastic modulus of the second sublayer is 20 to 300.

[0073] If the elastic modulus of the third sub-layer is too small, it will not be conducive to the absorption of longitudinal stress waves. If the difference between the elastic modulus of the second sub-layer and the elastic modulus of the third sub-layer is too large, that is, the elastic modulus of the third sub-layer is too large, it will not be conducive to the bending performance of the display device. If the elastic modulus of the second sub-layer 320 is too small, for example, some adhesive layers OCA glue has an elastic modulus in the kPa range. Its unique viscous flow characteristics make it difficult to disperse and absorb impact energy through in-plane vibration when subjected to impact. The ratio of the elastic modulus of the third sub-layer to the elastic modulus of the second sub-layer is 20 to 300, for example, any one of the ratios of 20, 50, 80, 100, 150, 200, 240, 250, 280, and 300.

[0074] In some embodiments, the elastic modulus of the third sublayer 330 is between 2000 MPa and 6000 MPa. A larger elastic modulus of the third sublayer is beneficial for the third sublayer to absorb longitudinal stress waves.

[0075] Comparing experimental groups 8 and 9, the combination design of high modulus + low modulus + high modulus reduced the strain of the encapsulation layer to about 0.42%, indicating that this design combination is beneficial to effectively reduce the size of the impact stress wave.

[0076] In some embodiments, the elastic modulus of the third sub-layer 330 is greater than that of the first sub-layer 310. As the third main line of defense against impact, the third sub-layer 330 provides better impact resistance. For the foldable display device 100, a higher elastic modulus of the third sub-layer 330 is more conducive to reducing creases and improving the visual appearance of the display device 100. The display panel 200 has a lower elastic modulus, making it prone to warping during bonding. The higher elastic modulus of the third sub-layer 330 strengthens the bonding to the display panel 200, ensuring the flatness of the film layer of the display device 100.

[0077] In some embodiments, please refer to Figure 1 , Figure 2 The thickness of the third sub-layer 330 is less than or equal to the thickness of the first sub-layer 310. If the thickness of the third sub-layer 330 is too large, the neutral layer of the display device 100 will shift away from the display panel 200. To keep the neutral layer close to the display panel 200, a thicker film layer needs to be provided on the backlight side of the display panel 200, increasing the overall thickness of the display device 100. This is detrimental to the thinning and lightening of the display device 100, and for a foldable display device 100, a larger thickness also hinders its bending. Therefore, the thickness of the third sub-layer 330 is less than or equal to the thickness of the first sub-layer 310. This ensures the impact resistance of the third sub-layer 330 while minimizing the impact on the neutral layer of the display device 100, thus guaranteeing the quality of the display device 100.

[0078] In some embodiments, please refer to Figure 1 , Figure 2 The thickness of the third sub-layer 330 is less than the thickness of the second sub-layer 320. The second sub-layer 320 has a lower elastic modulus, which is more conducive to absorbing longitudinal stress waves. Setting the thickness of the second sub-layer 320 to be thicker can more fully absorb longitudinal stress waves, reduce the energy of longitudinal stress waves passing through the second sub-layer 320, ensure the absorption of longitudinal stress waves, and help to hinder the propagation of stress waves, thus extending the service life of the display device 100.

[0079] In some embodiments, the third sublayer 330 may include any one of the following materials: polyimide, CPI (transparent polyimide), PET (polyethylene terephthalate), and acrylic polymers with high elastic modulus. Such materials have a high elastic modulus, allowing transverse stress waves to propagate rapidly within the surface. The large transverse material area facilitates the release or diffusion of stress from the transverse impact stress wave to the distal end of the impact region as the layer vibrates and deforms within the layer.

[0080] In some embodiments, the thickness of the third sublayer 330 is 23 μm to 50 μm.

[0081] In some embodiments, please refer to Figure 2 The impact-resistant layer 300 further includes a fourth sub-layer 340 and a fifth sub-layer 350. The fourth sub-layer 340 is located on the side of the third sub-layer 330 away from the first sub-layer 310, and the fifth sub-layer 350 is located on the side of the fourth sub-layer 340 away from the first sub-layer 310. The elastic modulus of the fifth sub-layer 350 is greater than that of the fourth sub-layer 340, and the elastic modulus of the third sub-layer 330 is greater than that of the fourth sub-layer 340.

[0082] The more layers of high and low elastic modulus membranes are stacked, the better the effect of blocking stress waves in the vertical direction. By using a multi-layered high-low-high-low-high elastic modulus impact-resistant layer 300, the impact resistance of the impact-resistant layer 300 is further improved. The working principle of the high-low-high-low-high elastic modulus impact-resistant layer 300 is similar to that of the high-low-high elastic modulus impact-resistant layer 300.

[0083] Comparing experimental groups 9 and 10, without significantly changing the thickness of the entire impact-resistant layer 300, the encapsulation layer strain decreased to about 0.41% when designed as a high-modulus + low-modulus + high-modulus + low-modulus + high-modulus stack. This indicates that the multi-layer composite design has some improvement, but it is not significant. This shows that when the drop ball 110 test height is constant, the three-layer stack design is sufficient to absorb impact stress. However, if a product with better impact resistance is considered, a multi-layer stack design can be adopted while taking into account bending performance.

[0084] In some embodiments, the number of sub-layers of the impact-resistant layer 300 can be more, such as six or seven layers, etc. This application will not list them all, but it is still necessary to consider the balance between film thickness and bending performance and set them in combination with actual parameter requirements.

[0085] In some embodiments, the ratio of the elastic modulus of the third sublayer to the elastic modulus of the fourth sublayer is 20 to 300.

[0086] If the elastic modulus of the fourth sub-layer is too large, it will not be conducive to the reflection of longitudinal stress waves back to the third sub-layer to protect the display panel 200, and will cause more longitudinal stress waves to penetrate into the display device 100. If the difference between the elastic modulus of the fourth sub-layer and the elastic modulus of the third sub-layer is too large, that is, the elastic modulus of the fourth sub-layer is too small, for example, some adhesive layers OCA adhesives have an elastic modulus of Kpa. Their unique viscous flow characteristics make it difficult to disperse and absorb impact energy through in-plane vibration when subjected to impact. The ratio of the elastic modulus of the third sub-layer to the elastic modulus of the fourth sub-layer is 20 to 300, for example, any one of the ratios of 20, 50, 80, 100, 150, 200, 240, 250, 280, and 300.

[0087] In some embodiments, the elastic modulus of the fourth sublayer 340 is between 20 MPa and 100 MPa.

[0088] If the elastic modulus of the fourth sub-layer is too large, it will not be conducive to the reflection of longitudinal stress waves back to the third sub-layer to protect the display panel 200, and will cause more longitudinal stress waves to penetrate into the display device 100. If the difference between the elastic modulus of the fourth sub-layer and the elastic modulus of the third sub-layer is too large, that is, the elastic modulus of the fourth sub-layer is too small, such as some adhesive layers OCA adhesive, which has an elastic modulus of Kpa. Its unique viscous flow characteristics make it difficult to disperse and absorb impact energy through in-plane vibration when subjected to impact.

[0089] In some embodiments, the ratio of the elastic modulus of the fifth sublayer to the elastic modulus of the fourth sublayer is 20 to 300.

[0090] If the elastic modulus of the fifth sublayer is too small, it will not be conducive to the absorption of longitudinal stress waves; if the elastic modulus of the fifth sublayer is too large, it will not be conducive to the bending performance of the display device. If the elastic modulus of the fourth sublayer is too small, for example, some adhesive layers such as OCA adhesive have an elastic modulus in the kPa range. Their unique viscous flow characteristics make it difficult to disperse and absorb impact energy through in-plane vibration when subjected to impact. The ratio of the elastic modulus of the fifth sublayer to the elastic modulus of the fourth sublayer is 20 to 300, for example, any one of the ratios of 20, 50, 80, 100, 150, 200, 240, 250, 280, and 300.

[0091] In some embodiments, the elastic modulus of the fifth sublayer is between 2000 MPa and 6000 MPa. A higher elastic modulus of the fifth sublayer is beneficial for its absorption of longitudinal stress waves.

[0092] In some embodiments, the elastic modulus of the fifth sub-layer 350 is greater than that of the first sub-layer 310, and the elastic modulus of the fifth sub-layer 350 is greater than that of the third sub-layer 330. The fifth sub-layer 350 has better impact resistance. For the foldable display device 100, the higher elastic modulus of the fifth sub-layer 350 is more conducive to reducing creases and improving the visual effect of the display device 100. The display panel 200 has a lower elastic modulus, which makes it prone to warping during bonding. The higher elastic modulus of the fifth sub-layer 350 can strengthen the bonding of the display panel 200 and ensure the flatness of the film layer of the display device 100.

[0093] In some embodiments, please refer to Figure 2 The sum of the thickness of the third sub-layer 330 and the thickness of the fifth sub-layer 350 is less than or equal to the thickness of the first sub-layer 310.

[0094] Specifically, the sum of the thickness of the third sub-layer 330 and the thickness of the fifth sub-layer 350 is less than or equal to the thickness of the second layer 312 of the first sub-layer 310. If the thickness of the third sub-layer 330 and the fifth sub-layer 350 is too large, it will cause the neutral layer of the display device 100 to move away from the display panel 200. Therefore, the thickness of the third sub-layer 330 and the fifth sub-layer 350 is less than or equal to the thickness of the first sub-layer 310. While ensuring the impact resistance of the third sub-layer 330 and the fifth sub-layer 350, the impact on the neutral layer of the display device 100 is reduced, thus ensuring the quality of the display device 100.

[0095] In some embodiments, please refer to Figure 2 The thickness of the fourth sub-layer 340 is greater than the thickness of the third sub-layer 330, and the thickness of the fourth sub-layer 340 is greater than the thickness of the fifth sub-layer 350.

[0096] The fourth sub-layer 340 has a lower elastic modulus, which is more conducive to absorbing longitudinal stress waves. Setting the thickness of the fourth sub-layer 340 to be thicker can more fully absorb longitudinal stress waves, reduce the energy of longitudinal stress waves passing through the fourth sub-layer 340, ensure the absorption of longitudinal stress waves, and help to hinder the propagation of stress waves, thus extending the service life of the display device 100.

[0097] In some embodiments, please refer to Figure 2 The thickness of the fourth sub-layer 340 is less than the thickness of the second sub-layer 320.

[0098] If the thickness of the fourth sub-layer 340 is too large, it will cause the neutral layer of the display device 100 to move away from the display panel 200. If the neutral layer is to be kept close to the display panel 200, a thicker film layer needs to be set on the backlight side of the display panel 200, which will increase the overall thickness of the display device 100. On the one hand, this is not conducive to the thinning of the display device 100. On the other hand, for a foldable display device 100, a larger thickness is not conducive to the bending of the display device 100. Therefore, the thickness of the fourth sub-layer 340 is less than the thickness of the second sub-layer 320. While ensuring the impact resistance of the fourth sub-layer 340, the impact on the neutral layer of the display device 100 is reduced, thus ensuring the quality of the display device 100.

[0099] In some embodiments, the thickness of the fourth sublayer 340 is 50 μm to 150 μm. The thickness of the fifth sublayer 350 is 15 μm to 25 μm.

[0100] In some embodiments, the strain rate of the fourth sublayer is less than or equal to 100 s⁻¹. -1 .

[0101] The greater the strain rate, the greater the increase in the elastic modulus of the film layer when subjected to impact. If the elastic modulus of the film layer increases significantly when subjected to impact, such as with the OCA adhesive layer, which is a high-molecular-weight adhesive material, it is prone to modulus enhancement under different impact intensities. That is, the greater the impact intensity, the stronger its viscoelastic effect, which macroscopically manifests as an increase in instantaneous modulus, leading to insufficient resistance to longitudinal stress waves. The material of the fourth sub-layer can be a stress rate (strain rate) independent layer material or a low stress (strain rate) rate material. That is, under impact load, the modulus of this layer material does not increase or the strength increases with the impact intensity; the material of this layer material can maintain the stability and uniformity of the modulus under impact load; or, the modulus of this layer material decreases with the increase of impact intensity under impact load, thereby ensuring that the elastic modulus of the fourth sub-layer of the display device 100 does not increase significantly under strong impact, avoiding a significant weakening of the fourth sub-layer's ability to absorb longitudinal stress waves, ensuring the absorption of longitudinal stress waves, and facilitating the obstruction of stress wave propagation.

[0102] Optionally, the strain rate of the fourth sublayer is 10s. -1 ~100s -1 .

[0103] In some embodiments, the material of the fourth sublayer may be selected from any one of polyurethane, toluene diisocyanate, polydimethylsiloxane, cyclomethylsiloxane, aminosiloxane, polymethylphenylsiloxane, and polyether polysiloxane copolymer. This type of material is a stress rate (strain rate) independent layer material or a low stress (strain rate) material, that is, under impact load, the modulus of this layer material does not increase or the strength increases with the change of impact strength. This type of material can also be modified to have better chemical stability, electrical insulation, weather resistance, and hydrophobicity, and has high shear resistance, and can be used for a long time at -50℃ to 200℃. At the same time, it has excellent physical properties, such as moisture resistance, insulation, damping, and shock absorption performance.

[0104] In some embodiments, the fifth sublayer may include any one of the following materials: polyimide, CPI (transparent polyimide), PET (polyethylene terephthalate), and acrylic-based polymers with high elastic modulus. Such materials have a high elastic modulus, allowing transverse stress waves to propagate rapidly within the plane. The large transverse material area facilitates the release or diffusion of stress from the transverse impact stress wave to the distal end of the impact region as the layer vibrates and deforms.

[0105] In some embodiments, please refer to Figure 2 The display device 100 includes a bending region 101 and a planar region 102 located on both sides of the bending region 101; the fourth sub-layer 340 includes a third part 341 disposed in the bending region 101 and a fourth part 342 disposed in the planar region 102; wherein the elastic modulus of the third part 341 is less than the elastic modulus of the fourth part 342.

[0106] The display device 100 has a bendable structure. The bending area 101 needs to have better bending performance. The fourth sub-layer 340 is a low elastic modulus film layer. While ensuring the impact resistance of the bending area 101, it can optimize the bending performance of the bending area 101 by further reducing the elastic modulus of the third part 341 in the bending area 101, thereby improving the bending performance of the bending area 101. This reduces the risk of damage to the display panel 200 in the bending area 101 by bending stress and extends the service life of the display device 100.

[0107] In some embodiments, please refer to Figure 1 , Figure 2 The impact-resistant layer 300 further includes an adhesive layer 400 disposed between any two adjacent film layers among the first sub-layer 310, the second sub-layer 320, the third sub-layer 330, the fourth sub-layer 340 and the fifth sub-layer 350.

[0108] For example, please see Figure 2The impact-resistant layer 300 further includes a first adhesive layer 410 disposed between the first sub-layer 310 and the second sub-layer 320, a second adhesive layer 420 disposed between the second sub-layer 320 and the third sub-layer 330, a third adhesive layer 430 disposed between the third sub-layer 330 and the fourth sub-layer 340, and a fourth adhesive layer 440 disposed between the fourth sub-layer 340 and the fifth sub-layer 350. The adhesive layer 400 may be an optical adhesive layer.

[0109] The optical adhesive material of the adhesive layer 400 can effectively absorb the bending strain of each film layer under bending conditions, and divide the entire display device into multiple neutral layers. Figure 9 In the middle, the neutral layer is represented by a dashed line, which makes each layer of material in a state of low stress and strain, thereby ensuring bending performance.

[0110] In some embodiments, the elastic modulus of any one of the first sub-layer 310, the second sub-layer 320, the third sub-layer 330, the fourth sub-layer 340, and the fifth sub-layer 350 is greater than the elastic modulus of any one of the first adhesive layer 410, the second adhesive layer 420, the third adhesive layer 430, and the fourth adhesive layer 440.

[0111] In some embodiments, the elastic modulus of the adhesive layer closer to the display panel 200 is higher. For example, the elastic modulus of the second adhesive layer 420 is greater than that of the first sub-layer 310. This provides better impact resistance. Since the display panel 200 has a lower elastic modulus, it is prone to warping during bonding. Placing the adhesive layer with a higher elastic modulus closer to the display panel 200 strengthens the bonding to the display panel 200 and ensures the flatness of the film layers in the display device 100.

[0112] In some embodiments, the display panel 200 may be a liquid crystal display panel 200 or a self-emissive display panel 200.

[0113] In some embodiments, the display panel 200 may be a liquid crystal display panel 200, which further includes a liquid crystal layer, a color filter layer, and upper and lower polarizing layers. The display module also includes a backlight unit corresponding to the display panel 200.

[0114] In some embodiments, the display panel 200 is a self-emissive display panel 200. The display panel 200 further includes a light-emitting device layer.

[0115] In some embodiments, please refer to Figure 1The display panel 200 is a self-emissive display panel 200. The display device 100 also includes a polarizing layer 360 disposed on the light-emitting side of the display panel 200. The polarizing layer 360 can also serve as a film layer in the impact-resistant layer 300.

[0116] In some embodiments, the display device 100 further includes a support layer 500 located on the side of the display panel 200 away from the light-emitting side. The support layer 500 includes a first support sublayer 510, a second support sublayer 520, and a third support sublayer 530. The first support sublayer 510 can be a back panel material, such as aluminum composite panel; the second support sublayer 520 can be a polymer material, such as PET; and the third support sublayer 530 can be a high elastic modulus material, such as stainless steel.

[0117] In some embodiments, the first support sublayer 510, the second support sublayer 520 and the third support sublayer 530 may be connected by an adhesive layer.

[0118] In some embodiments, please refer to Figure 1 , Figure 2 The third support sub-layer 530 may include a plurality of stress relief holes 531. The stress relief holes 531 are disposed within the bending area 101. The stress relief holes 531 may penetrate the third support sub-layer 530 or may not penetrate the third support sub-layer 530. The depth, density and other parameters may be set according to the actual situation, and no specific limitation is made here.

[0119] In some embodiments, please refer to Figure 1 , Figure 2 The display device 100 further includes a dustproof reinforcement layer 540, which is disposed on the side of the third support sub-layer 530 away from the display panel 200, and is disposed corresponding to the bending area 101.

[0120] This application provides an impact-resistant layer on the display panel, comprising at least two elastic modulus layers: a high-modulus layer and a low-modulus layer. When the display device is impacted, the impact energy propagates as stress waves in both lateral and longitudinal directions. The stress waves first contact the high elastic modulus film layer. The lateral stress waves propagate rapidly within the surface of the first sub-layer, which can quickly absorb the lateral stress waves with relatively small strain. The longitudinal stress waves continue to propagate inward in a direction perpendicular to the display device. When they contact the second sub-layer, which is a low elastic modulus layer, the second sub-layer is more likely to absorb the impact energy through greater deformation. Simultaneously, the stress waves propagate more easily in the high-modulus film layer. Because the elastic modulus difference between the second and first sub-layers is larger, the longitudinal stress waves are more easily reflected back to the first sub-layer, slowing down the tendency of the longitudinal stress waves to propagate further inward in a direction perpendicular to the display device. This is more beneficial for protecting the display panel and extending the service life of the display device.

[0121] This application discloses a display device; the display device includes a display panel and an impact-resistant layer. The impact-resistant layer includes at least two sub-layers, and adjacent sub-layers are bonded together by an adhesive layer. The at least two sub-layers include a first sub-layer and a second sub-layer between the first sub-layer and the display panel. The ratio of the elastic modulus of the first sub-layer to the elastic modulus of the second sub-layer is 20 to 300. The materials of the first sub-layer and the second sub-layer are different. By providing an impact-resistant layer with at least two elastic modulus layers (high and low) on the display panel, when the display device is impacted, the impact energy propagates as stress waves in both lateral and longitudinal directions. The lateral stress waves propagate rapidly within the surface of the first sub-layer, and the first sub-layer can quickly absorb the lateral stress waves with relatively small strain. The second sub-layer is more likely to absorb the impact energy through larger deformation, and the longitudinal stress waves are more easily reflected back to the first sub-layer.

[0122] The above provides a detailed description of a display device provided in the embodiments of this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A display device, characterized in that, include: Display panel; An impact-resistant layer is disposed on the light-emitting side of the display panel; The impact-resistant layer comprises at least two sub-layers, which are bonded together by an adhesive layer. The at least two sub-layers include a first sub-layer, a second sub-layer located on the side of the first sub-layer closer to the display panel, and a third sub-layer located on the side of the second sub-layer away from the first sub-layer. The ratio of the elastic modulus of the first sub-layer to the elastic modulus of the second sub-layer is 20 to 300. The material of the first sub-layer is different from that of the second sub-layer. The ratio of the elastic modulus of the third sub-layer to the elastic modulus of the second sub-layer is 20 to 300.

2. The display device according to claim 1, characterized in that, The first sublayer and / or the third sublayer each comprise any one of the following materials: polyimide, polyethylene terephthalate, and acrylic.

3. The display device according to claim 1, characterized in that, The strain rate of the second sublayer is less than or equal to 100 s⁻¹ -1 .

4. The display device according to claim 3, characterized in that, The second sublayer comprises any one of the following materials: polyurethane, toluene diisocyanate, polydimethylsiloxane, cyclomethylsiloxane, aminosiloxane, polymethylphenylsiloxane, and polyether polysiloxane copolymer.

5. The display device according to claim 1, characterized in that, The thickness of the second sublayer is greater than the thickness of the first sublayer.

6. The display device according to claim 1, characterized in that, The display device includes a bending area and planar areas located on both sides of the bending area; The second sub-layer includes a first portion disposed within the bending area and a second portion disposed within the planar area; The elastic modulus of the first part is smaller than that of the second part.

7. The display device according to any one of claims 1-6, characterized in that, The elastic modulus of the third sublayer is greater than that of the first sublayer.

8. The display device according to any one of claims 1-6, characterized in that, The thickness of the third sublayer is less than or equal to the thickness of the first sublayer.

9. The display device according to any one of claims 1-6, characterized in that, The material of the third sublayer is different from that of the second sublayer, and the thickness of the third sublayer is less than that of the second sublayer.

10. The display device according to any one of claims 1-6, characterized in that, The adhesive layer has a higher elastic modulus the closer it is to the display panel.

11. The display device according to claim 6, characterized in that, The impact-resistant layer further includes a fourth sub-layer and a fifth sub-layer, wherein the fourth sub-layer is located on the side of the third sub-layer away from the first sub-layer, and the fifth sub-layer is located on the side of the fourth sub-layer away from the first sub-layer; The elastic modulus of the fifth sub-layer is greater than that of the fourth sub-layer, and the elastic modulus of the third sub-layer is greater than that of the fourth sub-layer.

12. The display device according to claim 11, characterized in that, The ratio of the elastic modulus of the fifth sublayer to that of the fourth sublayer is 20 to 300, and the ratio of the elastic modulus of the third sublayer to that of the fourth sublayer is 20 to 300.

13. The display device according to claim 11, characterized in that, The elastic modulus of the fifth sublayer is greater than that of the first sublayer, and the elastic modulus of the fifth sublayer is greater than that of the third sublayer.

14. The display device according to claim 11, characterized in that, The sum of the thickness of the third sublayer and the thickness of the fifth sublayer is less than or equal to the thickness of the first sublayer.

15. The display device according to claim 11, characterized in that, The thickness of the fourth sub-layer is greater than the thickness of the third sub-layer, and the thickness of the fourth sub-layer is greater than the thickness of the fifth sub-layer.

16. The display device according to claim 11, characterized in that, The thickness of the fourth sublayer is less than the thickness of the second sublayer.

17. The display device according to claim 11, characterized in that, The impact-resistant layer further includes a first adhesive layer disposed between the first sub-layer and the second sub-layer, a second adhesive layer disposed between the second sub-layer and the third sub-layer, a third adhesive layer disposed between the third sub-layer and the fourth sub-layer, and a fourth adhesive layer disposed between the fourth sub-layer and the fifth sub-layer, wherein the elastic modulus of any one of the first sub-layer, the second sub-layer, the third sub-layer, the fourth sub-layer, and the fifth sub-layer is greater than the elastic modulus of any one of the first adhesive layer, the second adhesive layer, the third adhesive layer, and the fourth adhesive layer.

18. The display device according to claim 11, characterized in that, The strain rate of the fourth sublayer is less than or equal to 100 s⁻¹ -1 .

19. The display device according to claim 18, characterized in that, The fourth sublayer comprises any one of the following materials: polyurethane, toluene diisocyanate, polydimethylsiloxane, cyclomethylsiloxane, aminosiloxane, polymethylphenylsiloxane, and polyether polysiloxane copolymer. The fifth sublayer includes any one of the following materials: polyimide, polyethylene terephthalate, and acrylic.

20. The display device according to claim 1, characterized in that, The first sub-layer includes a first layer and a second layer, wherein the second layer is located on the side of the first layer closer to the display panel; The hardness of the first layer is greater than that of the second layer.

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