Flexible screen folding structure and folding terminal with same

Abstract

The invention provides a flexible screen folding structure and a folding terminal with the same, the flexible screen folding structure comprises a shell and an electronic component, the flexible screen folding structure is loaded in the flexible screen shell, the flexible screen folding structure comprises a flexible screen, and the flexible screen folding structure further comprises a supporting assembly used for bearing the flexible screen, comprising a first rotating part and a second rotating part which are arranged at an interval and fixedly connected with the flexible screen; the flexible bending part is made of a thermosensitive shape memory material, and the flexible bending part of the flexible screen is connected to the two sides of the thickness between the first rotating part of the flexible screen and the second rotating part of the flexible screen so as to form an accommodating space for accommodating the bending part of the flexible screen in a folded state; and the temperature field generating assembly is used for receiving an external signal so as to transmit heat to the flexible bending part of the flexible screen or stop transmitting heat to the flexible bending part of the flexible screen. Compared with a traditional rigid mechanical folding structure, the structure has the advantages of being high in durability and free of mechanical abrasion.

Description

Technical Field

[0001] This invention relates to the field of electronic product technology, and in particular to a flexible screen folding structure and a folding terminal having the same structure. Background Technology

[0002] Flexible screens are the core of foldable displays for foldable terminals. To accommodate the flexible screen's curved section when folded, existing technologies reserve corresponding space in the inner arc of the curved section. However, when the display is unfolded, the presence of this space causes the flexible screen to suspend in mid-air, failing to connect with other internal components, resulting in a situation where the screen does not shrink tightly.

[0003] To address this issue, Chinese invention patent CN108508970B provides a foldable terminal with a flexible screen, comprising a shell, two main bodies, a flexible screen, a first airbag, and a second airbag. The two main bodies are fixed to the shell. The flexible screen includes two fixed areas and a bending area, with the bending area connecting the two fixed areas. The first airbag is positioned between the bending area and the bending section, and the second airbag is positioned on the main body. The first and second airbags are connected and filled with sealed gas. In the folded state, the sealed gas is located in the second airbag. When unfolded, the sealed gas moves from the second airbag to the first airbag, causing the first airbag to inflate and support the inner side of the bending area. This solves the technical problem of the middle part, i.e., the bending area, being suspended and providing a poor pressing experience when the flexible screen is opened. After folding, under the pressure of the bending area, the first airbag can provide space for the flexible screen to bend, preventing the bending area from being damaged by compression.

[0004] While the aforementioned technical solution provides support for the unfolded flexible screen through the inflated first airbag, the first and second airbags remain connected. When the bending area of ​​the flexible screen is pressed, the external force compresses the first airbag, causing the internal gas to flow back to the second airbag. This causes the first airbag to contract directly, resulting in the pressure point of the flexible screen sinking and failing to provide stable support. Furthermore, because the first airbag is a flexible cavity and remains connected to the second airbag, the gas flow within it is asynchronous and uneven during pressing. The pressure is greatest at the pressed area of ​​the first airbag, causing gas to rapidly flow to the surrounding areas or the second airbag, resulting in sinking at that location. Meanwhile, the unpressed areas of the first airbag remain inflated, and the flexible screen remains stationary. This localized sinking and overall immobility creates stress differences in the bending area of ​​the flexible screen. Since the flexible screen is a multi-layered composite structure, long-term stress differences can lead to interlayer delamination and circuit breakage, significantly reducing the lifespan of the flexible screen. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a flexible screen folding structure and a folding terminal having the structure, so as to solve the problem that the flexible screen has a reduced service life due to stress differences at different positions in the bending area of ​​the flexible screen when it is folded.

[0006] To achieve the above and other related objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides a flexible screen folding structure, including a flexible screen, and further comprising: The support assembly for supporting the flexible screen includes a first rotating part and a second rotating part that are spaced apart and fixedly connected to the flexible screen respectively; A flexible bending section made of thermal shape memory material is connected to both sides of the thickness between the first rotating section and the second rotating section to form an accommodating space for accommodating the bending area of ​​the flexible screen in a folded state; and... A temperature field generating component used to receive external signals to deliver heat to or stop the flexible bending section.

[0007] To achieve the above solution, a signal for supplying heat is input to the temperature field generating component according to the folding requirements. The flexible bending part receives the heat input from the temperature field generating component and changes its modulus, entering an easily bendable state. Force is applied to the first rotating part / second rotating part, causing it to bend towards the second rotating part / first rotating part. The bending flexible bending part drives the flexible screen to extend into the accommodating space, and the flexible screen separates from the flexible bending part. The deformation of the flexible bending part will not pull or squeeze the flexible screen, avoiding the stress concentration problem caused by the direct transfer of mechanical deformation to the flexible screen in traditional folding structures, thereby reducing physical damage to the flexible screen. At the same time, the design of the accommodating space allows the flexible screen to naturally extend into the accommodating space when folded, avoiding the problem of internal circuit breakage and pixel layer damage caused by forced sharp angle folding; thus improving the service life of the flexible screen. The flexible bending part, made of thermal shape memory material, has a locking function. After the temperature field generating component stops supplying heat, the flexible bending part remains bent; after the same amount of heat is supplied again, the flexible bending part autonomously returns to its initial state, that is, it drives the first rotating part / second rotating part to unfold, and the flexible screen flattens out at the same time. Compared to traditional rigid mechanical folding structures, it has the advantages of high structural durability and no mechanical wear.

[0008] In one embodiment of the present invention, the temperature field generating component includes a controller for receiving external signals, and a heating filament polymer coupled to the controller and disposed within the flexible bending portion.

[0009] To achieve the above solution, the temperature field generating component receives externally input demand signals through a controller. The controller then sends control signals to the heating filament polymer based on the received demand signals. The heating filament polymer then delivers heat to the flexible bending section or stops, thereby changing the modulus of the flexible bending section.

[0010] In one embodiment of the present invention, the flexible bending portion includes a first support layer and a second support layer respectively connected to both sides of the thickness between the first rotating portion and the second rotating portion, and the heating filament polymer is disposed within the first support layer and the second support layer.

[0011] In one embodiment of the present invention, the controller is disposed on the opposite side surface of the first support layer and the second support layer.

[0012] To achieve the above solution, the first support layer and the second support layer are respectively connected to the two sides of the thickness between the first rotating part and the second rotating part, thereby forming an accommodating space between the first support layer and the second support layer to accommodate the bending point of the flexible screen in the folded state, thus avoiding damage to the flexible screen due to forced bending into an acute angle.

[0013] In one embodiment of the present invention, the heating filament polymer is a mixture of single-walled carbon nanotubes and resin-based shape memory polymer.

[0014] In one embodiment of the present invention, the heating filament polymer is a liquid metal and a nano-silver wire.

[0015] In one embodiment of the present invention, the controller is a near-infrared light generator disposed on the opposite side surfaces of the first support layer and the second support layer.

[0016] In one embodiment of the present invention, the controller is a circuit board disposed on the opposite side surfaces of the first support layer and the second support layer.

[0017] In one embodiment of the present invention, the thermosensitive shape memory material used in the flexible bending portion is a resin-based shape memory polymer.

[0018] To achieve the above solution, resin-based shape memory polymers are high-molecular polymers with excellent flexibility and large deformation capacity, exhibiting uniform deformation without hard folds. They also possess excellent shape-locking ability, allowing for precise repositioning after folding / unfolding, and their fatigue resistance meets the requirements of high-frequency folding applications. Furthermore, the thermotropic modulus change characteristics of resin-based shape memory polymers are controllable; they exhibit high modulus and rigidity at room temperature, providing stable support for flexible screens; at mild phase transition temperatures, they soften rapidly, with a sharp drop in modulus, allowing for easy bending; and the trigger temperature can be customized through material formulation, thus avoiding the temperature range commonly used in daily applications and preventing accidental deformation.

[0019] In an embodiment of the present invention, the first support layer includes a horizontal layer provided with a heat-generating filamentous polymer and a U-shaped layer provided on the side of the horizontal layer facing away from the flexible screen; the structure of the second support layer is the same as that of the first support layer.

[0020] In an embodiment of the present invention, the controller is disposed at the bottom of the U-shaped layer.

[0021] Implementing the above solution, the U-shaped layers of the first support layer and the second support layer are disposed opposite to each other to form a "mouth" shape, planning a fixed and non-offset stretching area for the bending part of the flexible screen in the folded state, guiding the bending part of the flexible screen to naturally extend into the accommodating space, avoiding left / right or up / down offset and wrinkle accumulation, and ensuring the uniqueness and accuracy of the folding trajectory of the flexible screen.

[0022] In an embodiment of the present invention, the heat-generating filamentous polymer is arranged in a grid pattern.

[0023] Implementing the above solution, the heat-generating filamentous polymer releases uniform heat throughout the horizontal layer.

[0024] On the other hand, the present invention provides a folding terminal, including a housing and electronic components, and further including the flexible screen folding structure as described in any one of the above.

[0025] Implementing the above solution, the folding terminal having the above flexible screen folding structure has the advantages of high structural durability, no mechanical wear, and being able to adapt to the high-frequency folding requirements of the folding terminal.

[0026] In an embodiment of the present invention, the electronic components are loaded in the support assembly.

[0027] Implementing the above technical solution, the flexible screen folding structure can be well integrated with other necessary components of the folding terminal, avoiding increasing the structural complexity of the folding terminal.

[0028] As described above, a flexible screen folding structure and a folding terminal having the structure provided by the present invention have the following beneficial effects: This invention provides a flexible screen folding structure and a folding terminal having the structure, including a shell and electronic components, and a flexible screen folding structure mounted within the shell. The flexible screen folding structure includes a flexible screen and further includes: a support component for supporting the flexible screen, comprising a first rotating part and a second rotating part arranged at intervals and fixedly connected to the flexible screen; a flexible bending part made of a thermosensitive shape memory material, the flexible bending part being connected to both sides of the thickness between the first rotating part and the second rotating part to form an accommodating space for accommodating the bending portion of the flexible screen in a folded state; and a temperature field generating component for receiving external signals to supply heat to the flexible bending part or to stop the heat supply. The flexible bending part made of thermosensitive shape memory material has the advantages of precise and controllable thermal modulus change, high modulus and strong rigidity at room temperature, providing stable support for the flexible screen; it can quickly soften at the mild phase change temperature supplied by the temperature field generating component, with a sharp drop in modulus, making it easy to bend; and it has a locking function, after the same amount of heat is supplied again, the flexible bending part can autonomously return to its initial state, i.e., it drives the first rotating part / second rotating part to unfold, and the flexible screen flattens out simultaneously. The design of the separable and stackable flexible bending section and the flexible screen, along with the accommodating space, allows the flexible screen to naturally extend into the accommodating space under the guidance of the flexible bending section during folding. This avoids physical damage to the flexible screen caused by stress concentration and forced folding into sharp angles. Compared to traditional rigid mechanical folding structures, it has the advantages of high structural durability and no mechanical wear. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the overall structure of an exemplary folding terminal in a specific embodiment of the present invention; Figure 2 This is an exploded view of an exemplary folding terminal in a specific embodiment of the present invention; Figure 3 This is a schematic diagram of an exemplary flexible screen folding structure in a specific embodiment of the present invention; Figure 4 This is a specific embodiment of the present invention. Figure 3 A schematic diagram of the support structure of an exemplary flexible screen folding structure; Figure 5 This is a schematic diagram of another exemplary flexible screen folding structure in a specific embodiment of the present invention; Figure 6 This is a schematic diagram of the folded state of the folding terminal in a specific embodiment of the present invention; Figure 7 This is an image of a dispersion suspension of a heating filamentous polymer material; Figure 8 This is a graph showing the change of energy storage modulus with temperature and the change of the ratio of viscous to elastic components with temperature. Figure 9This is a graph showing the variation of storage modulus of SMP+CNT at different concentrations with shear force and shear rate. Figure 10 This is a graph showing the photothermal properties of a heat-generating filamentous polymer. Figure 11 It is a flowchart of how a physical object is folded and restored to its initial state; Figure 12 It is a thermal image of the actual object under NIR illumination; Figure 13 This is a picture of a product with a flexible screen. Figure 14 This is a picture of the flexible screen in operation. Figure 15 This is a picture of the actual object folded at 90 degrees; Figure 16 This is a picture of the actual object folded at 120 degrees; Figure 17 This is a diagram showing the state of the flexible bending section when the actual object is folded 120 degrees. Figure 18 This is a picture of the actual object fully folded; Figure 19 This is a diagram of the hinge when the object is fully folded. Figure 20 It is a flowchart of the physical object going from folded to restored.

[0030] Explanation of the technical feature labels in the attached drawings: 6. Fold lines; 100. Folding terminal; 101. Housing; 200. Flexible screen; 300. Flexible screen folding structure; 301. Support component; 3011. First rotating part; 3012. Second rotating part; 302. Flexible bending part; 3021. First support layer; 3022. Second support layer; 3023. Horizontal layer; 3024. U-shaped layer; 303. Accommodation space; 304. Temperature field generating component; 3041. Near-infrared light generator; 3042. Circuit board; 3043. Heating filament polymer; 305. First support body; 306. Second support body; 307. First end cap; 308. Second end cap. Detailed Implementation

[0031] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0032] Please see Figures 1 to 20It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings are merely for illustrative purposes to aid those skilled in the art and to facilitate understanding and reading. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, the terms such as "upper," "lower," "left," "right," "middle," and "one" used in this specification are merely for clarity and not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0033] The foldable terminal 100 provided by this invention can be a handheld portable electronic device such as a mobile phone, tablet computer, or media player, or it can be another small wearable electronic device such as a wristband or headband. It can also be applied to leisure and entertainment devices such as games and navigation. That is, it is not limited to a certain type of device or instrument, nor is it limited to a certain specific shape. It can be applied to any scenario with display requirements.

[0034] See Figure 1 and Figure 2 The present invention provides a folding terminal 100, including a housing 101, electronic components and a flexible screen folding structure 300 mounted in the housing 101.

[0035] For ease of explanation and illustration, Figure 1 Taking the rectangular folding terminal 100 shown as an example, the folding terminal 100 has a front F, a back R and a side W, and can be folded along the folding line 6.

[0036] See Figures 2 to 4 The flexible screen folding structure 300 includes a flexible screen 200, a support assembly 301 for supporting the flexible screen 200, a flexible bending portion 302, and a temperature field generating assembly 304. Specifically, the support assembly 301 includes a first rotating portion 3011 and a second rotating portion 3012 arranged at intervals and respectively fixedly connected to the flexible screen 200. In a specific embodiment, portions of the flexible screen 200 corresponding to the first rotating portion 3011 and the second rotating portion 3012 are fixedly connected to the first rotating portion 3011 and the second rotating portion 3012 respectively by adhesive bonding. The first rotating portion 3011 and the second rotating portion 3012 are frame-shaped structures with a certain thickness, and electronic components are loaded inside the support assembly 301, specifically inside the first rotating portion 3011 and the second rotating portion 3012. The electronic components include control circuits, communication circuits, input / output components, sensors, and speakers necessary for realizing the folding terminal 100.

[0037] The flexible bending part 302 is connected to the two thickness sides between the first rotating part 3011 and the second rotating part 3012. Specifically, the flexible bending part 302 includes a first support layer 3021 and a second support layer 3022 respectively corresponding to and connected to the two thickness sides between the first rotating part 3011 and the second rotating part 3012. An accommodation space 303 is formed between the first support layer 3021 and the second support layer 3022. The first rotating part 3011, the first support layer 3021 / second support layer 3022, and the second rotating part 3012 form a plane for carrying the flexible screen 200. For the convenience of description, taking the flexible screen 200 carried on the plane formed by the first rotating part 3011, the first support layer 3021, and the second rotating part 3012 as an example, the flexible screen 200 can be detachably laminated with the first support layer 3021. When folded, the flexible screen 200 is separated from the first support layer 3021 and the bent part is accommodated in the accommodation space 303. Specifically, Figure 6 The folding state of the folding structure of the flexible screen 200 is shown. The first support layer 3021 buckles towards the accommodation space 303 until it abuts against the second support layer 3022, and drives the second support layer 3022 to extend. The buckled first support layer 3021 forms a "water droplet-shaped" bending space in the accommodation space 303. The flexible screen 200 is separated from the buckled first support layer 3021 and folded into an arc shape and stored in the bending space. The arc-shaped flexible screen 200 can avoid stress concentration and improve the service life of the flexible screen 200.

[0038] Refer to Figure 2 and Figure 5 In a preferred embodiment, the first support layer 3021 includes a horizontal layer 3023 that is laminated and in contact with the flexible screen 200 and a U-shaped layer 3024 provided on the side of the horizontal layer 3023 facing away from the flexible screen 200. The structure of the second support layer 3022 is the same as that of the first support layer 3021. The U-shaped layers 3024 of the first support layer 3021 and the second support layer 3022 are arranged oppositely to form a "mouth" shape. The accommodation space 303 in the "mouth" shape plans a fixed and non-offset stretching area for the bent part of the flexible screen 200 in the folded state, guides the bent part of the flexible screen 200 to naturally extend into the accommodation space 303, avoids left / right or up / down offset and wrinkle accumulation, and ensures the uniqueness and accuracy of the folding trajectory of the flexible screen 200.

[0039] Specifically, the flexible bending part 302 uses a thermosensitive shape memory material. Under specific stimuli, the flexible bending part 302 can adjust its modulus, changing from a glassy state to a rubbery state. In the rubbery state, the flexible bending part 302 is easy to bend and has a locking function. After the external stimulus is removed, the flexible bending part 302 can maintain its bent state. At the same time, the thermosensitive shape memory material used in the flexible bending part 302 also has a shape memory function. After the specific stimulus conditions are reapplied, the flexible bending part 302 can autonomously recover its initial state.

[0040] Specifically, the flexible bending portion 302 is made of a resin-based shape memory polymer, such as polyurethane-based shape memory polymer (SMPU). See also... Figure 2 In one specific embodiment, the first support body 305 and the second support body 306 are integrally formed by additive manufacturing. The flexible bending portion 302 corresponds to the portion of the first support body 305 and the second support body 306 connecting the first rotating portion 3011 and the second rotating portion 3012. Specifically, the first support layer 3021 corresponds to the portion of the first support body 305 located between the first rotating portion 3011 and the second rotating portion 3012, and similarly, the second support layer 3022 corresponds to the portion of the second support body 306 located between the first rotating portion 3011 and the second rotating portion 3012. The first rotating portion 3011 and the second rotating portion 3012 are frame-shaped structures with openings on both the upper and lower sides. The first support body 305 is connected to the upper opening of the first rotating portion 3011 and the second rotating portion 3012 by a snap-fit ​​mechanism. Similarly, the second support body 306 is connected to the lower opening of the first rotating portion 3011 and the second rotating portion 3012 by a snap-fit ​​mechanism. The upper surface of the first support body 305 forms a plane that supports the flexible screen 200. In a preferred embodiment, a U-shaped layer 3024 is integrally formed on the opposing surfaces of the first support 305 and the second support 306, and the U-shaped layer 3024 is located on the opposing surfaces of the first support layer 3021 and the second support layer 3022.

[0041] See Figure 3In another specific embodiment, the flexible bending portion 302 is integrally formed between the first rotating portion 3011 and the second rotating portion 3012. The first rotating portion 3011 and the second rotating portion 3012 are frame-shaped structures with openings on one side. The openings of the first rotating portion 3011 and the second rotating portion 3012 are respectively connected to the first end cap 307 and the second end cap 308 through slots. The upper surface of the first end cap 307, the upper surface of the first support layer 3021 of the flexible bending portion 302, and the upper surface of the second end cap 308 form a plane that supports the flexible screen 200. The flexible screen 200 is fixedly connected to the upper surfaces of the first end cap 307 and the second end cap 308 by adhesive bonding. The flexible screen 200 and the upper surface of the first support layer 3021 can be separated and stacked. The materials of the first end cap 307 and the second end cap 308 are the same as those of the first rotating portion 3011 and the second rotating portion 3012, and all of them can be made of shape memory polymer.

[0042] This invention uses a temperature field generating component 304 to stimulate a flexible bending portion 302 to bend as needed or return to its initial state. Specifically, the temperature field generating component 304 receives external signals and supplies heat to or stops the flexible bending portion 302, including a controller for receiving external signals and a heating filament polymer 3043 coupled to the controller and disposed within the flexible bending portion 302. Specifically, the heating filament polymer 3043 is disposed within a first support layer 3021 and a second support layer 3022, the controller is disposed on the opposite side surfaces of the first support layer 3021 and the second support layer 3022, and the controller is coupled to an input / output component to receive a demand signal input through the input / output component. In a preferred embodiment, the heating filament polymer 3043 is disposed in a horizontal layer 3023 and arranged in a grid pattern; the controller is disposed at the bottom of a U-shaped layer 3024.

[0043] See Figure 5 In one specific embodiment, the heating filament polymer 3043 is a mixture of single-walled carbon nanotubes (SWCNTs) and resin-based shape memory polymers (SMPs). The corresponding controller is a near-infrared light generator 3041 disposed on the opposite side surfaces of the first support layer 3021 and the second support layer 3022. In a preferred embodiment, the near-infrared light generator 3041 is disposed at the bottom of the U-shaped layer 3024. Figure 7Images of redispersed suspensions at different concentrations of single-walled carbon nanotubes (SWCNTs) are shown. Heated filamentous polymer 3043 is embedded in the first support layer 3021 and the second support layer 3022 via 3D printing. The printing performance varies with different SWCNT mass fractions (wt%). 1wt.%SWCNT, 2wt.%SWCNT, and 3wt.%SWCNT are in a liquid state and are not suitable for printing. 4wt.%SWCNT and 5wt.%SWCNT have good printing performance, while 6wt.%SWCNT is difficult to extrude.

[0044] Figure 8 The graphs show the viscoelastic modulus of the exothermic filamentary polymer (SWCNT+SMP) and the shape memory polymer (SMP) as a function of temperature. Figure 8 The graph (a) shows the changes in storage modulus, loss modulus, and the ratio of storage modulus to storage modulus (tanδ) of SWCNT+SMP printing ink with temperature. Its storage modulus is 1.4 GPa at 20℃, gradually decreasing with increasing temperature. It reaches a minimum of 0.1 GPa at 55℃, after which the storage modulus hardly changes with temperature. The viscoelastic characterization parameter (tanδ) of SWCNT+SMP increases from 0.4 to a maximum of 0.68 as the temperature rises to 67℃, then decreases with further temperature increases, stabilizing at 0.06 at 120℃. Figure 8 Figure (b) shows the change of viscoelastic properties of SMP with temperature. The storage modulus of SMP is 1.5 GPa at 20℃. Initially, the storage modulus hardly changes with increasing temperature. When the temperature reaches 50℃, the storage modulus begins to decrease rapidly with increasing temperature, reaching a minimum of 0.1 GPa at 60℃, and then hardly changes with temperature. The viscoelastic ratio of SMP initially hardly changes with increasing temperature. When the temperature reaches 50℃, the ratio begins to increase rapidly with increasing temperature, reaching a maximum of 1.24 at 67℃. After the temperature exceeds 67℃, the ratio decreases with increasing temperature, and tends to stabilize after 100℃, with the ratio dropping to 0.1.

[0045] Figure 9 In Figure (a), the apparent viscosity of photothermal shape memory polymer printing inks with different SWCNT doping concentrations changes with shear rate. The apparent viscosity of SWCNTs with different concentrations decreases with increasing shear rate. The higher the SWCNT concentration, the less the apparent viscosity decreases. Figure 9Figure (b) shows the change in apparent viscosity of the photothermal shape memory polymer with the SWCNT doping ratio. The apparent viscosity of the photothermal shape memory polymer increases with the increase of the SWCNT doping ratio. When the SWCNT doping ratio is less than 3.4 wt.%, the apparent viscosity of the printing ink is low, and the ink is liquid, which is not suitable for 3D printing. When the concentration is 3.4% to 5.7%, the apparent viscosity is moderate, and it has good plasticity, which can be used for 3D printing. When the concentration exceeds 5.7%, the apparent viscosity is too high, and the ink cannot be extruded. Figure 9 Figure (c) shows the variation of shear storage modulus of photothermal shape memory polymers with different SWCNT concentrations as a function of shear stress. The doping ratio of SWCNT has a significant impact on the storage modulus of the printing ink; the higher the doping amount, the higher the initial storage modulus of the printing ink. The initial storage modulus of the printing ink containing 1 wt.% SWCNT is 1.5 Pa. When the doping amount is increased to 5.5 wt.% SWCNT, the initial storage modulus of the printing ink increases by 330,000 times, reaching 500,000 Pa. Figure 9 (d) shows the variation of shear yield stress of photothermal shape memory polymer printing ink with SWCNT concentration. The shear yield stress of SWCNT+SMP ink increases with the increase of SWCNT doping amount, and the ink has the best printing performance when the doping amount is between 3.3wt.% and 4.8wt.%.

[0046] Figure 10 (a) shows a shape memory polymer cube with embedded vertically heating polymer filaments. The cube measures 15×15×8mm. The curve depicts the trend of the highest temperature at the center of the heating polymer filaments as a function of infrared laser power: the highest temperature of the SWCNT+SMP polymer increases linearly with increasing near-infrared irradiation power. The lowest irradiation power (2mW / cm²) is also shown. 2 Near-infrared light can raise the core temperature of polymers to 36.9℃, while at 14mW / cm 2 Under near-infrared light, the printing filament can reach a maximum temperature of 148.6℃. Figure 10 Figure (b) shows the curves of the core temperature of the heating filamentous polymer as a function of irradiation time under near-infrared irradiation of different powers. The time for the polymer core temperature to reach its maximum value increases with increasing irradiation power. The initial temperature of the sample starts from 20℃, and the irradiation time is 2mW / cm². 2 Near-infrared light can heat the polymer to a steady-state temperature of 36.9°C in just 10 seconds, while 14 mW / cm 2 Near-infrared light takes 80 seconds to heat the polymer to a steady-state temperature of 148.6°C. Figure 10 The temperature field distribution of SMP cubic samples under different irradiation temperatures was analyzed using finite element simulation. Figure 10In the middle (c), the temperature field distribution in the plane (XY plane) is shown. The highest temperature is at the center of the filamentous polymer, at a distance of 7.8 mm. The temperature decreases as the distance increases. The radius of influence of the temperature field generated by infrared irradiation is 4.8 mm. Figure 10 In Figure (d), the out-of-plane (along the Z-axis) temperature field distribution is shown, i.e., the distribution along the length of the filamentous polymer. At Z=0, the SWCNT+SMP polymer irradiated surface temperature is the highest, and the temperature decreases continuously with increasing depth. The maximum influence range of the temperature field generated by surface irradiation is 6 mm.

[0047] Figure 11 The photograph shows a physical embodiment of this patent folded back to its initial state. The physical sample has overall dimensions of 150mm (length), 72mm (width), and 8mm (thickness). A heating filament polymer 3043 is embedded in the flexible bending section 302 using 3D printing technology. The first rotating section 3011 and the second rotating section 3012 have spaces for placing electronic components. The accommodating space 303 is a through-hole 72mm long and 18mm wide. During folding, the flexible screen 200 separates from the first support layer 3021, and the bent portion is accommodated within the accommodating space 303. Irradiation by an infrared light generator (3041) brings the flexible bending section 302 to the glass-rubber phase transition temperature of the shape memory polymer. An external force is applied as needed to flip the first rotating section 3011 towards the second rotating section 3012, causing them to overlap face-to-face. Near-infrared irradiation stops, and the flexible bending section 302 maintains its folded state after cooling. If near-infrared light irradiation is triggered again as needed, the first and second rotating parts can be flipped into an unfolded state as the shape of the flexible bending part is restored, utilizing the shape memory characteristics of the flexible bending part. After the near-infrared light irradiation is stopped, the flexible rotating part is cooled to room temperature and restores its high modulus state to support the flexible display screen.

[0048] Figure 12 This is a thermal image of an embodiment of this patent under irradiation by a near-infrared light generator 3041. The power is 11 mW / cm². 2 The near-infrared irradiated heating filament polymer 3043 can reach a temperature of 102.3°C in the flexible bending part 302, while the first rotating part 3011 and the second rotating part 3012 remain at room temperature.

[0049] Figure 13 This is a photograph of a preferred embodiment of the present invention. A flexible screen 200 is installed on the flexible bending part 302, the first rotating part 3011, and the second rotating part 3012. Figures 14 to 20 This is the process of folding and restoring the physical object of this invention patent. Figure 14In the middle, the flexible screen 200 is in working state. The near-infrared light generator 3041 excites the heating filament polymer 3043 to generate a thermal field, causing the flexible bending part 302 to change its modulus. In this way, external force can be applied to fold it to different angles, and the bending angle can be locked after the near-infrared light is removed: 90°. Figure 15 ), 60° Figure 16 ), 45° Figure 17 ) and 0° ( Figure 18 , Figure 19 ). Figure 17 and Figure 19 These are detailed images of the flexible bending section 302 folded to 60° and 90° respectively. After the first support layer 3021 buckles and deforms, it is stored in the accommodating space 303, which at the same time forms a space to accommodate the flexible screen 200 when it is bent. Figure 18 Even when fully folded, the flexible screen 200 functions normally and is undamaged. Figure 20 The photos show the actual folding and restoration process of the flexible screen 200, from its initial state to its folded and fixed state, and finally back to its initial state. The illustrations demonstrate the good working condition of the flexible screen 200, proving that the present invention has the advantages of high structural durability and no mechanical wear.

[0050] See Figure 4 In another specific embodiment, the heating filament polymer 3043 is composed of liquid metal and nano-silver wires. The corresponding controller is a circuit board 3042 disposed on the opposite side surfaces of the first support layer 3021 and the second support layer 3022. In a preferred embodiment, the circuit board 3042 is disposed at the bottom of the U-shaped layer 3024 and electrically connected to a switch in the input / output assembly. After the switch of the circuit board 3042 is turned on, the liquid metal and nano-silver wires are connected, and the first support layer 3021 and the second support layer 3022 are heated by the Joule effect, changing the modulus of the first support layer 3021 and the second support layer 3022 and reducing the bending stiffness. Specifically, the liquid metal and nano-silver wires generate heat through electricity, inducing the flexible bending part 302 to change its material phase: from a glassy state to a rubbery state. The flexible bending part 302 in the rubbery state is easy to bend. The user flips the first rotating part 3011 toward the second rotating part 3012 as needed, so that the two overlap face to face.

[0051] The present invention provides a flexible screen folding structure 300 and a folding terminal 100 having the structure. The flexible bending part 302, made of thermally sensitive shape memory material, has the advantage of controllable thermal modulus change characteristics. It has high modulus and sufficient rigidity at room temperature, which can provide stable support for the flexible screen 200. Under the mild trigger temperature provided by the temperature field generating component 304, it can soften rapidly, the modulus drops sharply, and it can be easily bent. The first rotating part 3011 / second rotating part 3012 bends towards the first rotating part 3011 / second rotating part 3012 to form a folded state. The thermally sensitive shape memory material used in the flexible bending part 302 has a shape-locking function. After the same heat is supplied again, the flexible bending part 302 can autonomously return to its initial state, that is, drive the first rotating part 3011 / second rotating part 3012 to unfold, and the flexible screen 200 flattens out at the same time. The design of the separable stacking of the flexible bending portion 302 and the flexible screen 200, along with the accommodating space 303, allows the flexible screen 200 to naturally extend into the accommodating space 303 under the guidance of the flexible bending portion 302 during folding. This avoids physical damage to the flexible screen 200 caused by stress concentration or forced folding into a sharp angle. Compared to traditional rigid mechanical folding structures, this invention has the advantages of high structural durability, no mechanical wear, and adaptability to the high-frequency folding requirements of the folding terminal 100.

[0052] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A flexible screen folding structure, comprising a flexible screen (200), characterized in that, Also includes: The support assembly (301) for supporting the flexible screen (200) includes a first rotating part (3011) and a second rotating part (3012) arranged at intervals and respectively fixedly connected to the flexible screen (200); A flexible bending portion (302) made of thermal shape memory material is connected to both sides of the thickness between the first rotating portion (3011) and the second rotating portion (3012) to form an accommodating space (303) for accommodating the bending point of the flexible screen (200) in a folded state; and, A temperature field generating component for receiving external signals to deliver heat to or stop the flexible bending section (302).

2. The flexible screen folding structure according to claim 1, characterized in that, The temperature field generating component includes a controller for receiving external signals and a heating filament polymer (3043) coupled to the controller and disposed within the flexible bending portion (302).

3. The flexible screen folding structure according to claim 2, characterized in that, The flexible bending portion (302) includes a first support layer (3021) and a second support layer (3022) respectively connected to the thickness sides of the first rotating portion (3011) and the second rotating portion (3012), and the heating filament polymer (3043) is disposed in the first support layer (3021) and the second support layer (3022).

4. The flexible screen folding structure according to claim 3, characterized in that, The controller is disposed on the opposite side surface of the first support layer (3021) and the second support layer (3022).

5. The flexible screen folding structure according to claim 4, characterized in that, The heating filament polymer (3043) is a mixture of single-walled carbon nanotubes and resin-based shape memory polymer.

6. The flexible screen folding structure according to claim 4, characterized in that, The heating filament polymer (3043) is a liquid metal and nano-silver wire.

7. A flexible screen folding structure according to claim 5, characterized in that, The controller is a near-infrared light generator (3041) disposed on the opposite side surfaces of the first support layer (3021) and the second support layer (3022).

8. A flexible screen folding structure according to claim 6, characterized in that, The controller is a circuit board (3042) disposed on the opposite side surfaces of the first support layer (3021) and the second support layer (3022).

9. A flexible screen folding structure according to claim 3, characterized in that, The flexible bending part (302) uses a thermosensitive shape memory material, which is a resin-based shape memory polymer.

10. A flexible screen folding structure according to claim 3, characterized in that, The first support layer (3021) includes a horizontal layer (3023) on which heating filament polymer (3043) is arranged and a U-shaped layer (3024) on the side of the horizontal layer (3023) facing away from the flexible screen (200); the structure of the second support layer (3022) is the same as that of the first support layer (3021).

11. A flexible screen folding structure according to claim 10, characterized in that, The controller is located at the bottom of the U-shaped layer (3024).

12. A flexible screen folding structure according to claim 10, characterized in that, The heating filament polymer (3043) is arranged in a mesh pattern.

13. A folding terminal, comprising a housing (101) and electronic components, characterized in that, It also includes a flexible screen folding structure (300) as described in any one of claims 1-11, mounted within the housing (101).

14. A folding terminal according to claim 13, characterized in that, The electronic components are mounted inside the support assembly (301).

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