Flexible display panel and flexible display device

Abstract

The application relates to a flexible display panel and a flexible display device. The flexible display panel comprises a substrate, an array film layer arranged on one side of the substrate and located in the first flat area, the second flat area and the bending area, a light emitting device layer arranged on one side of the array film layer and located in the first flat area, the second flat area and the bending area, and a resistance change layer located on one side of the substrate and located in the bending area. The resistance change layer comprises at least one resistance change element, and the extension direction of the resistance change element intersects with the bending axis of the bending area. The resistance value of the resistance change element changes according to the bending state of the bending area. The application can improve the problem of poor display control of the foldable terminal partition.

Description

Technical Field

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

[0002] With the rapid development of the mobile internet, mobile devices such as smartphones and tablets have become deeply integrated into people's daily lives, becoming the most frequently used consumer electronics products. Among these mobile devices, the display screen, as a key component for intuitively presenting information and showcasing the user interface, has always attracted much attention for its technological innovation. Among them, flexible displays have stood out, and their unique bendable characteristics have given rise to the innovative application of foldable displays, opening up new ideas for the design and usage of mobile devices.

[0003] In related technical fields, foldable mobile terminal architectures typically encompass a main screen and a secondary screen. This design aims to balance portability with a large-screen operating experience, meeting diverse user needs in different scenarios. Specifically, when the foldable terminal is folded, the main screen folds down and enters an off-screen state to save power and prevent accidental touches, while the secondary screen is activated. Users can perform various operations through the secondary screen, such as viewing notifications and quickly replying to messages, providing basic interactive functions in the foldable portable mode thanks to the smaller size of the secondary screen. Conversely, when the terminal is unfolded, the advantages of a large screen become apparent, with the main screen providing a wide field of view. At this time, the secondary screen is off, and the user shifts their focus to the main screen. However, foldable terminals suffer from poor partitioned display control. Summary of the Invention

[0004] Therefore, it is necessary to provide a flexible display panel and a flexible display device to address the above-mentioned problems.

[0005] In a first aspect, this application provides a flexible display panel having a first flat area, a second flat area, and a bending area, wherein the bending area connects the first flat area and the second flat area; the flexible display panel has a folded state and an unfolded state; in the folded state, the first flat area and the second flat area are opposite to each other; in the unfolded state, the first flat area, the bending area, and the second flat area are arranged sequentially along a first direction; the flexible display panel includes:

[0006] Base;

[0007] An array film layer is disposed on one side of the substrate and located in the first flat region, the second flat region, and the bending region;

[0008] A light-emitting device layer is disposed on one side of the array film layer and is located in the first flat region, the second flat region and the bending region;

[0009] A resistive switching layer is located on one side of the substrate and in the bending region; the resistive switching layer includes at least one resistive switching element, the extension direction of which intersects the bending axis of the bending region; wherein the resistive switching element is configured such that its resistance value changes according to the bending state of the bending region.

[0010] The flexible display panel provided in this application embodiment features a resistive switching layer in the bending region, comprising at least one resistive switching element whose resistance changes according to the bending state of the bending region. Thus, during the folding or unfolding process, the bending state of the bending region changes, and the resistance of the resistive switching element also changes, allowing the flexible display device to promptly acquire the bending state and control the display and screen-off states of the flexible display panel. Furthermore, by aligning the extension direction of the resistive switching element with the bending axis of the bending region, not only is the resistance change of the resistive switching element more sensitive, but the structural stability of the resistive switching element is also improved.

[0011] In one embodiment, the extension direction of the resistive element is perpendicular to the bending axis of the bending region.

[0012] In one embodiment, the bending region has a first center line parallel to its own extension direction; the first center line passes through the resistive element;

[0013] Optionally, the first center line passes through the center of the resistive element;

[0014] Optionally, the resistive element is symmetrically arranged about the first center line.

[0015] In one embodiment, the resistive switching layer includes a plurality of resistive switching elements, which are arranged at axial intervals along the bending axis.

[0016] In one embodiment, the resistive element includes a first extension, a second extension, and an outward protrusion;

[0017] The first extension and the second extension are arranged at intervals along the first direction, and the outward protrusion is provided on the same side of the first extension and the second extension along the second direction, and the outward protrusion connects the first extension and the second extension; the second direction is perpendicular to the first direction and parallel to the bending axis of the bending area;

[0018] Optionally, the first extension has a second center line parallel to the first direction, and the second extension has a third center line parallel to the first direction, wherein the second center line coincides with the third center line.

[0019] In one embodiment, the array film layer includes an active layer, and the resistive switching layer is disposed in the same layer and with the same material as the active layer.

[0020] In one embodiment, the array film layer includes multiple metal layers, and the resistive switching layer is disposed in the same layer and with the same material as one of the multiple metal layers.

[0021] In one embodiment, the flexible display panel further includes a touch electrode layer, and the resistive switching layer is disposed in the same layer and with the same material as the touch electrode layer.

[0022] Secondly, embodiments of this application also provide a flexible display device, comprising:

[0023] The first and second housings are rotatably connected;

[0024] The flexible display panel according to any embodiment of the first aspect is disposed on the same side of the first housing and the second housing, wherein a first area of ​​the flexible display panel is connected to the first housing and a second area of ​​the flexible display panel is connected to the second housing;

[0025] The first display panel is located on the side of the first housing opposite to the flexible display panel.

[0026] The flexible display device provided in this application embodiment provides a resistive switching layer in the bending region, and this layer includes at least one resistive switching element whose resistance changes according to the bending state of the bending region. Thus, during the folding or unfolding process, the bending state of the bending region changes, and the resistance of the resistive switching element also changes. This allows the flexible display device to promptly acquire the bending state and control the display and screen-off states of the flexible display panel and the first display panel. Furthermore, by making the extension direction of the resistive switching element intersect the bending axis of the bending region, not only is it beneficial to make the resistance change of the resistive switching element more sensitive, but it also helps to improve the structural stability of the resistive switching element.

[0027] In one embodiment, the flexible display device further includes a distance sensor;

[0028] The distance sensor is located at the end of the first housing away from the bending area, or the distance sensor is located at the end of the second housing away from the bending area; the distance sensor is used to detect the distance between the end of the first housing away from the bending area and the end of the second housing away from the bending area. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of a flexible display panel in a folded state, as provided in an embodiment of this application.

[0030] Figure 2 for Figure 1 The diagram shows a flexible display panel in its unfolded state.

[0031] Figure 3 for Figure 1 Another schematic diagram of the flexible display panel in its unfolded state.

[0032] Figure 4 for Figure 1 The diagram shows the structure of the resistive switching element in the flexible display panel.

[0033] Figure 5 for Figure 1 The diagram shows the working principle of the resistive switching component in the flexible display panel.

[0034] Figure 6 for Figure 1 The diagram shows a cross-sectional structure of a flexible display panel.

[0035] Figure 7 for Figure 1 This is a schematic diagram of another cross-sectional structure of the flexible display panel shown.

[0036] Figure 8 This is a schematic diagram of a flexible display device in a folded state, according to an embodiment of this application.

[0037] Figure 9 This is a schematic diagram of another flexible display device in a folded state, provided as an embodiment of this application.

[0038] Figure 10 for Figure 8 The diagram shows a partial cross-sectional structure of the flexible display device.

[0039] Explanation of reference numerals in the attached figures:

[0040] 100. Flexible display device; 10. Flexible display panel; 10a. First flat area; 10b. Bending area; 10c. Second flat area; 11. Screen body; 111. Substrate; 112. Array film layer; 113. Light-emitting device layer; 12. Resistive switching layer; 121. Resistive switching element; 1211. First extension; 1212. Second extension; 1213. Outward protrusion; 13. Touch electrode layer; 141. First support layer; 142. Second support layer; 15. Polarizing layer; 16. First adhesive layer; 17. First cover plate; 18. Second adhesive layer; 19. Second cover plate; 20. First housing; 30. Second housing; 40. Distance sensor; 50. First display panel; O1. First center line; O2. Second center line; O3. Third center line; C. Bending axis; X. First direction; Y. Second direction. Detailed Implementation

[0041] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0042] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0043] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0044] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0045] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0046] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0047] With the rapid development of the mobile internet, mobile devices such as smartphones and tablets have become deeply integrated into people's daily lives, becoming the most frequently used consumer electronics products. Among these mobile devices, the display screen, as a key component for presenting information and showcasing the user interface, has always attracted much attention for its technological innovation. Flexible display technology has emerged as a standout, with its unique bendable characteristics giving rise to the innovative application of foldable displays, opening up entirely new avenues for the design and use of mobile devices.

[0048] In current technological fields, foldable mobile terminal architectures typically encompass a main screen and a secondary screen. This design aims to balance portability with a large-screen operating experience, meeting diverse user needs in different scenarios. Specifically, when the foldable terminal is folded, the main screen folds down and enters an off-screen state to save power and prevent accidental touches, while the secondary screen is activated. Users can perform various operations through the secondary screen, such as viewing notifications and quickly replying to messages, providing basic interactive functions in the foldable portable mode thanks to the smaller size of the secondary screen. Conversely, when the terminal is unfolded, the advantages of a large screen become apparent. The unfolded main screen provides a wide field of view, and the secondary screen is off. Users can then shift their focus to the main screen and enjoy an immersive large-screen experience, such as watching videos and multitasking.

[0049] However, in practical applications, foldable terminals have revealed a significant problem: poor partitioned display control. On the one hand, display delays often occur when switching between the main screen and the secondary screen. For example, when switching from a folded state to an unfolded state, the main screen should light up quickly and smoothly take over the operation logic and display content from the secondary screen. However, in reality, the main screen lights up slowly, or there are brief screen freezes or flickering, which disrupts the continuity of operation. Users have to wait for the system to respond, greatly affecting the efficiency and smoothness of use.

[0050] In view of this, embodiments of this application provide a flexible display panel and a flexible display device. By providing a resistive layer in the bending region, and making the resistive layer include at least one resistive element, the resistance value of which changes according to the bending state of the bending region. Thus, during the folding or unfolding process of the flexible display device, the bending state of the bending region changes, and the resistance value of the resistive element also changes. This allows the flexible display device to promptly obtain the bending state, thereby controlling the display and screen-off states of the flexible display panel and the first display panel in a timely manner, improving the problem of poor partitioned display control in foldable terminals. Furthermore, by making the extension direction of the resistive element intersect the bending axis of the bending region, not only is it beneficial to make the resistance value change of the resistive element more sensitive, but it is also beneficial to improve the structural stability of the resistive element.

[0051] Firstly, such as Figures 1-7 As shown, this application embodiment provides a flexible display panel 10, which can be an organic light-emitting diode (OLED) display panel, a quantum dot light-emitting diode (QLED) display panel, a liquid crystal display (LCD), a mini light-emitting diode (Mini LED) display panel, or a micro light-emitting diode (Micro LED) display panel.

[0052] Specifically, the flexible display panel 10 has a first flat area 10a, a second flat area 10c, and a bending area 10b, with the bending area 10b connecting the first flat area 10a and the second flat area 10c. The flexible display panel 10 has a folded state and an unfolded state; in the folded state, the first flat area 10a and the second flat area 10c are opposite to each other, and the bending area 10b is in a bent state. In the unfolded state, the first flat area 10a, the bending area 10b, and the second flat area 10c are arranged sequentially along a first direction X, with the bending area 10b in a flat state (or a similarly flat state).

[0053] The flexible display panel 10 includes a screen body 11 and a resistive switching layer 12. The screen body includes a substrate 111, an array film layer 112, and a light-emitting device layer 113. The array film layer 112 is disposed on one side of the substrate 111 and is located in a first flat region 10a, a second flat region 10c, and a bending region 10b. The light-emitting device layer 113 is disposed on one side of the array film layer 112 and is located in the first flat region 10a, the second flat region 10c, and the bending region 10b. The resistive switching layer 12 is located on one side of the substrate 111 and is located in the bending region 10b. The resistive switching layer 12 includes at least one resistive element 121, the extension direction of which intersects the bending axis C of the bending region 10b. The resistive element 121 is configured such that its resistance changes according to the bending state of the bending region 10b.

[0054] It should be noted here that the extension direction of the resistive inverter 121 refers to the length direction of the resistive inverter 121. The bending region 10b extends along the second direction Y, and the extension direction (i.e., the length direction) of the bending region 10b is parallel to the second direction Y. When the bending region 10b bends, it bends around the bending axis C, and the bending axis C is parallel to the extension direction of the bending region 10b.

[0055] Understandably, when the bending region 10b is bent, the stress in the bending region 10b will change, and the resistance of the resistive element 121 will change according to the stress. For example, the material of the resistive element 121 can be a piezoresistive material, a piezoelectric material, a conductive elastomer, a liquid metal, graphene and its derivatives, carbon nanotubes, metal nanowires, etc. Piezoresistive materials deform their internal structure due to mechanical stress, thereby changing the electron transport path and altering the impedance (resistance value). Piezoresistive materials include monocrystalline silicon, polycrystalline silicon, copper-nickel alloys, nickel-chromium alloys, and conductive polymer composites, such as carbon nanotubes / polymers and graphene / PDMS (polydimethylsiloxane). Piezoelectric materials polarize under mechanical stress, accumulating surface charge and forming a potential difference, causing the impedance (resistance value) to change with stress. Piezoelectric materials include quartz, lead zirconate titanate, and polyvinylidene fluoride. Conductive elastomers are elastic polymers (such as silicone rubber and polyurethane) filled with conductive particles (such as silver, carbon black, and graphene). Deformation causes changes in the spacing between the fillers, leading to the connection or disconnection of conductive pathways, resulting in a step-like or continuous change in impedance (resistance). Typical materials for conductive elastomers include carbon black / silicone rubber composites and silver nanowire / PDMS (polydimethylsiloxane) composites. Liquid metals change shape during deformation, causing changes in the length or cross-sectional area of ​​conductive pathways, thus altering impedance (resistance); or the contact area changes when flowing in microchannels. Typical materials for liquid metals include gallium indium tin alloys. The resistivity switching principle of graphene derivatives: When single-layer or multi-layer graphene is stretched or bent, the carbon atom lattice distortion leads to changes in the electronic band structure, resulting in a change in resistivity; or when a graphene film deforms on a substrate, cracks form, changing the contact resistance. The resistivity switching principle of carbon nanotubes: Single-walled or multi-walled carbon nanotubes undergo changes in electron orbital hybridization under stress, or the carbon nanotube network breaks / connects during stretching, leading to changes in impedance (resistance). Typical materials using carbon nanotubes include: carbon nanotube / polymethyl methacrylate composites and carbon nanotube films. The resistive switching principle of metal nanowires: When a metal nanowire deforms, the nanowire junctions break or re-connect, leading to a non-linear change in impedance (resistance value).

[0056] The flexible display panel 10 provided in this application embodiment has a resistive switching layer 12 provided in the bending region 10b, and the resistive switching layer 12 includes at least one resistive switching element 121. The resistance value of the resistive switching element 121 changes according to the bending state of the bending region 10b. In this way, when the flexible display panel 10 is folded or unfolded, the bending state of the bending region 10b changes, and the resistance value of the resistive switching element 121 also changes, which facilitates the flexible display device 100 to obtain the bending state in a timely manner, thereby controlling the display and screen-off of the flexible display panel 10 in a timely manner. Furthermore, by making the extension direction of the resistive switching element 121 intersect the bending axis C of the bending region 10b, it is not only beneficial to make the resistance value change of the resistive switching element 121 more sensitive, but also beneficial to improve the structural stability of the resistive switching element 121.

[0057] In one embodiment, the extension direction of the resistive variable 121 is perpendicular to the bending axis C of the bending region 10b. In other words, the extension direction of the resistive variable 121 is parallel to the first direction X.

[0058] It should be noted that, through experiments, the inventors discovered that when the extension direction of the resistive variable element 121 is parallel to the bending axis C of the bending region 10b, the strain value of the resistive variable element 121 is 0.2562%, and the detected voltage change is 0.05V; when the extension direction of the resistive variable element 121 is perpendicular to the bending axis C of the bending region 10b, the strain value of the resistive variable element 121 is 0.2843%, and the detected voltage change is 0.35V. It is evident that when the extension direction of the resistive variable element 121 is perpendicular to the bending axis C of the bending region 10b, the stress change and resistance change of the resistive variable element 121 are larger, facilitating a better acquisition of the bending state. Furthermore, the stress change causes less damage to the resistive variable element 121, and its characteristics do not undergo significant shifts, which is beneficial for improving the structural stability of the resistive variable element 121.

[0059] In one embodiment, the circuit principle for obtaining the bending state (or bending angle) through the resistance change of the resistive element 121 is as follows: Figure 5 As shown, R4 represents the impedance of resistor 121, offset represents the compensator, and Amplifier represents the amplifier. A preset voltage is applied across resistor 121, and the voltage change across resistor 121 and R3 is detected. After processing by the amplifier, the data is transmitted to the chip.

[0060] In one embodiment, such as Figure 2 and Figure 3 As shown, the bending region 10b has a first center line O1 parallel to its own extension direction; the first center line O1 passes through the resistive inverter 121. Here, it can also be understood that the orthogonal projection of the bending region 10b on the substrate 111 has a first center line O1 parallel to the second direction Y, and the first center line O1 passes through the orthogonal projection of the resistive inverter 121 on the substrate 111.

[0061] This not only makes the resistance value of the resistive variable 121 more sensitive to changes, but also helps to improve the structural stability of the resistive variable 121.

[0062] In one embodiment, the first center line O1 passes through the center of the resistive inverter 121. Thus, on the one hand, the stress change of the resistive inverter 121 is relatively large, resulting in a large change in resistance, which facilitates better acquisition of the bending state; on the other hand, the stress change causes less damage to the resistive inverter 121, and the characteristics of the resistive inverter 121 do not undergo significant shifts, which is beneficial to improving the structural stability of the resistive inverter 121.

[0063] In one embodiment, the resistive inverter 121 is symmetrically arranged about the first center line O1. This results in two advantages: firstly, the resistive inverter 121 experiences greater stress and resistance variations, facilitating better acquisition of the bending state; secondly, stress variations cause less damage to the resistive inverter 121, preventing significant shifts in its characteristics and improving its structural stability.

[0064] In one embodiment, such as Figure 3 As shown, the resistive switching layer 12 includes multiple resistive switching elements 121, which are arranged at intervals along the axial direction of the bending axis C. This allows for more sensitive changes in resistance during bending, enabling better acquisition of the bending (or folding) state.

[0065] In one embodiment, such as Figure 4 As shown, the resistive variable element 121 includes a first extension 1211, a second extension 1212, and an outward protrusion 1213. The first extension 1211 and the second extension 1212 are arranged at intervals along a first direction X. The outward protrusion 1213 is provided on the same side of the first extension 1211 and the second extension 1212 along a second direction Y, and the outward protrusion 1213 connects the first extension 1211 and the second extension 1212. The second direction Y is perpendicular to the first direction X, and the second direction Y is parallel to the bending axis C of the bending region 10b.

[0066] Thus, on the one hand, the stress change of the resistive variable 121 is large, and the resistance value changes significantly, making it easier to obtain the bending state; on the other hand, the stress change causes less damage to the resistive variable 121, and the characteristics of the resistive variable 121 will not deviate significantly, which is beneficial to improving the structural stability of the resistive variable 121.

[0067] In one embodiment, the first extension 1211 has a second center line O2 parallel to the first direction X, and the second extension 1212 has a third center line O3 parallel to the first direction X, with the second center line O2 coinciding with the third center line O3. Thus, on the one hand, the stress change of the resistive inverter 121 is large, resulting in a large change in resistance, which facilitates better acquisition of the bending state; on the other hand, the stress change causes less damage to the resistive inverter 121, and the characteristics of the resistive inverter 121 do not undergo significant shift, which is beneficial to improving the structural stability of the resistive inverter 121.

[0068] In one embodiment, the first extension 1211 is symmetrically arranged about the second center line O2.

[0069] Thus, on the one hand, the stress change of the resistive variable 121 is large, and the resistance value changes significantly, making it easier to obtain the bending state; on the other hand, the stress change causes less damage to the resistive variable 121, and the characteristics of the resistive variable 121 will not deviate significantly, which is beneficial to improving the structural stability of the resistive variable 121.

[0070] In one embodiment, the second extension 1212 is symmetrically arranged about the third center line O3.

[0071] Thus, on the one hand, the stress change of the resistive variable 121 is large, and the resistance value changes significantly, making it easier to obtain the bending state; on the other hand, the stress change causes less damage to the resistive variable 121, and the characteristics of the resistive variable 121 will not deviate significantly, which is beneficial to improving the structural stability of the resistive variable 121.

[0072] In one embodiment, the orthographic projection of the protrusion 1213 onto the substrate 111 is symmetrical about the first centerline O1.

[0073] Thus, on the one hand, the stress change of the resistive variable 121 is large, and the resistance value changes significantly, making it easier to obtain the bending state; on the other hand, the stress change causes less damage to the resistive variable 121, and the characteristics of the resistive variable 121 will not deviate significantly, which is beneficial to improving the structural stability of the resistive variable 121.

[0074] In one embodiment, the orthographic projection of the first extension 1211 on the substrate 111 and the orthographic projection of the second extension 1212 on the substrate 111 are symmetrically arranged about the first centerline O1.

[0075] Thus, on the one hand, the stress change of the resistive variable 121 is large, and the resistance value changes significantly, making it easier to obtain the bending state; on the other hand, the stress change causes less damage to the resistive variable 121, and the characteristics of the resistive variable 121 will not deviate significantly, which is beneficial to improving the structural stability of the resistive variable 121.

[0076] In one embodiment, the array film layer 112 includes an active layer, and the resistive switching layer 12 is disposed in the same layer and with the same material as the active layer. In other words, as... Figure 6 As shown, the resistive switching layer 12 is located within the array film layer 112. Thus, the resistive switching layer 12 can be fabricated simultaneously with the active layer, which helps reduce fabrication costs.

[0077] In one embodiment, the array film layer 112 includes multiple metal layers, and the resistive switching layer 12 is disposed in the same layer and with the same material as one of the metal layers. In other words, as... Figure 6 As shown, the resistive switching layer 12 is located within the array film layer 112. Thus, the resistive switching layer 12 can be fabricated simultaneously with the metal layer, which helps reduce fabrication costs.

[0078] In one embodiment, such as Figure 7 As shown, the flexible display panel 10 also includes a touch electrode layer 13, and the resistive switching layer 12 is disposed in the same layer and with the same material as the touch electrode layer 13. In this way, the resistive switching layer 12 can be fabricated simultaneously when the touch electrode layer 13 is fabricated, which helps to reduce the fabrication cost.

[0079] In one embodiment, the resistive switching layer 12 is made of materials such as Mo, Ti, and Al. In one example, the resistive switching layer 12 is a Ti / Al / Ti stacked structure.

[0080] In one embodiment, the flexible display panel 10 further includes a pixel defining layer (not shown), which is disposed on the side of the array film layer 112 away from the substrate 111, and has a plurality of pixel openings. The light-emitting device layer 113 includes a plurality of light-emitting devices (not shown), each including a first electrode, a light-emitting structure, and a second electrode stacked along a direction away from the substrate 111. The plurality of light-emitting devices are correspondingly disposed at the plurality of pixel openings. The first electrode can be an anode, the second electrode can be a cathode, and the light-emitting structure includes at least an emission layer (EML), and may also include one or more of a hole injection layer (HIL), a hole transport layer (HTL), an electron injection layer (EIL), an electron transport layer (ETL), a hole block layer (HBL), and an electron block layer (EBL). Alternatively, the light-emitting structure can also be a stacked light-emitting structure, that is, it includes at least two light-emitting layers and a charge generation layer (CGL) located between each adjacent light-emitting layer.

[0081] Secondly, embodiments of this application also provide a flexible display device 100. The flexible display device 100 can be a laptop computer, mobile phone, wireless device, personal data assistant (PDA), handheld or portable computer, GPS receiver / navigator, camera, MP4 video player, camcorder, game console, watch, clock, calculator, television monitor, flat panel display, computer monitor, automotive display (e.g., odometer display), navigator, cockpit controller and / or display, camera view display (e.g., display of a rearview camera in a vehicle), electronic photograph, electronic billboard or sign, projector, packaging, etc. (See also...) Figures 8-10As shown, the flexible display device 100 provided in this application embodiment takes a foldable screen mobile phone as an example.

[0082] For example, the foldable phone described in this application embodiment is a foldable phone including an inner screen and an outer screen. The inner screen can also be called a foldable screen, a foldable inner screen, or a large inner screen, and its screen size is generally similar to that of mainstream tablet devices. The outer screen's screen size is generally consistent with that of a candybar phone. Generally, the inner screen's screen size is much larger than the outer screen's screen size; for example, the inner screen's screen size is twice the size of the outer screen's screen size.

[0083] In other words, in this article, both the outer screen and the inner screen are complete screens. The inner screen refers to a foldable screen, in which the two folding surfaces can be bent so that they overlap. The outer screen refers to the screen in a foldable phone that can still be used and receive touch operations when the foldable screen is in a folded state and cannot receive touch operations.

[0084] Generally, foldable phones can be either large-screen inward-folding phones or large-screen outward-folding phones. A large-screen inward-folding phone refers to a phone that folds horizontally in the same direction as the inner screen when unfolded. The inner screen of a large-screen inward-folding phone can be folded along the folding axis in the same direction as the inner screen's orientation, thus placing the inner screen in a folded state. The inner screen of a large-screen inward-folding phone can be divided into two screens along the folding axis; these two screens are generally symmetrical.

[0085] A large-screen outward-folding phone refers to a phone that folds horizontally in the opposite direction to the orientation of the inner screen when it is unfolded. This type of phone can be folded along the folding axis in the opposite direction to the orientation of the inner screen, so that the inner screen is in a folded state. If the inner screen of a large-screen outward-folding phone is divided into screen four and screen five along the folding axis, these screens are generally asymmetrical. For example, the outer screen of a large-screen outward-folding phone shares the same display screen as screen four (screen four with a camera assembly on the back). That is, the outer screen and screen four are the same screen. Screen four has a camera assembly on its back, and when the inner screen is folded, the back of screen five can be embedded into the back of screen four.

[0086] Specifically, the flexible display device 100 includes a first housing 20, a second housing 30, a flexible display panel 10, and a first display panel 50. The first housing 20 and the second housing 30 are rotatably connected; exemplarily, the first housing 20 and the second housing 30 are rotatably connected via a hinge mechanism. The flexible display panel 10 is disposed on the same side of the first housing 20 and the second housing 30. The flexible display panel 10 has a first flat area 10a, a second flat area 10c, and a bending area 10b, with the bending area 10b connecting the first flat area 10a and the second flat area 10c. The flexible display panel 10 has a folded state and an unfolded state; in the folded state, the first flat area 10a and the second flat area 10c are opposite each other, and the bending area 10b is in a bent state. In the unfolded state, the first flat area 10a, the bending area 10b, and the second flat area 10c are arranged sequentially along a first direction X, with the bending area 10b in a flat state (or a similarly flat state). The flexible display panel 10 includes a substrate 111, an array film layer 112, a light-emitting device layer 113, and a resistive switching layer 12. The array film layer 112 is disposed on one side of the substrate 111 and is located in a first flat region 10a, a second flat region 10c, and a bending region 10b. The light-emitting device layer 113 is disposed on one side of the array film layer 112 and is located in the first flat region 10a, the second flat region 10c, and the bending region 10b. The resistive switching layer 12 is located on one side of the substrate 111 and is located in the bending region 10b; the resistive switching layer 12 includes at least one resistive element 121, the extension direction of which intersects the bending axis C of the bending region 10b; wherein the resistive element 121 is configured such that its resistance changes according to the bending state of the bending region 10b. The first region of the flexible display panel 10 is connected to a first housing 20, and the second region of the flexible display panel 10 is connected to a second housing 30. The first display panel 50 is located on the side of the first housing 20 opposite to the flexible display panel 10.

[0087] The flexible display device 100 provided in this application embodiment provides a resistive switching layer 12 in the bending region 10b, and the resistive switching layer 12 includes at least one resistive switching element 121. The resistance value of the resistive switching element 121 changes according to the bending state of the bending region 10b. Thus, during the folding or unfolding process of the flexible display device 100, the bending state of the bending region 10b changes, and the resistance value of the resistive switching element 121 also changes. This allows the flexible display device 100 to promptly obtain the bending state, thereby timely controlling the display and screen-off states of the flexible display panel 10 and the first display panel 50, improving the problem of poor zone display control in the flexible display device 100. Furthermore, by making the extension direction of the resistive switching element 121 intersect the bending axis C of the bending region 10b, it not only facilitates more sensitive changes in the resistance value of the resistive switching element 121 but also improves the structural stability of the resistive switching element 121. It can be understood that the flexible display panel 10 is equivalent to the foldable inner screen mentioned above, and the first display panel 50 is equivalent to the outer screen mentioned above.

[0088] In one embodiment, the flexible display device 100 includes a chip, and a resistive switching element 121, a flexible display panel 10, and a first display panel 50 are all electrically connected to the chip. The chip controls the display or screen-off state of the flexible display panel 10 and the first display panel 50 based on the resistance value of the resistive switching element 121.

[0089] In one embodiment, such as Figure 9 As shown, the flexible display device 100 also includes a distance sensor 40. The distance sensor 40 is located at the end of the first housing 20 away from the bending region 10b, or at the end of the second housing 30 away from the bending region 10b. The distance sensor 40 is used to detect the distance between the end of the first housing 20 away from the bending region 10b and the end of the second housing 30 away from the bending region 10b. Thus, by detecting the distance between the end of the first housing 20 and the end of the second housing 30 away from the bending region 10b, it is possible to determine whether the flexible display panel 10 is in a folded state and whether the degree of folding meets preset conditions. Furthermore, superimposing the resistive switching element 121 with the distance sensor 40 helps the chip to more accurately obtain the folding state (bending state).

[0090] In one embodiment, a distance sensor 40 is provided at the end of the first housing 20 away from the bending region 10b, and a distance sensor 40 is also provided at the end of the second housing 30 away from the bending region 10b. This improves detection accuracy.

[0091] In one example, the distance sensor 40 can be an infrared light distance sensor 40, which includes an infrared signal emitting tube and a photosensitive receiving tube. The emitting tube emits infrared signals of a specific frequency, and the receiving tube receives these characteristic frequency infrared signals. When the infrared detection direction encounters an obstacle, the infrared signal is reflected back and received by the receiving tube. After processing, the signal is returned to the host computer via a digital sensor interface. The host computer can then use the returned infrared signal to identify changes in the surrounding environment.

[0092] 1) The distance can be calculated based on the fact that infrared light emitted from the infrared emitter is reflected by a reflective object and then received by a photosensitive receiver. The distance can then be calculated using the time from emission to reception and the speed of infrared light propagation. For example, the time difference Δt between the emission and reception times of the infrared beam can be calculated using the phase shift generated by the high-frequency modulated infrared light traveling back and forth at the distance to be measured. The distance D can then be obtained using the formula D (distance) = C (infrared beam propagation speed) * Δt / 2.

[0093] 2) The ranging principle of the infrared distance sensor 40 is that the light-emitting tube emits infrared light, and the photosensitive receiving tube receives the light reflected from the object in front, thereby determining whether there is an obstacle in front. Among them, the light intensity received by the photosensitive receiving tube changes with the distance of the reflecting object. The closer the object is, the stronger the reflected light is, and the farther the object is, the weaker the reflected light is. Thus, the distance of the object can be determined based on the intensity of the emitted light.

[0094] In another example, distance sensor 40 is an ultrasonic distance sensor 40, which includes an ultrasonic transmitter and an ultrasonic receiver. The ultrasonic transmitter emits ultrasonic waves in a certain direction, and a timer starts simultaneously with the emission. The ultrasonic waves propagate through the air, and upon encountering an obstacle, they immediately return. The ultrasonic receiver stops the timer immediately upon receiving the reflected wave. Based on the speed of sound in the air (e.g., 340 m / s) and the time t (seconds) recorded by the timer, the distance (s) from the emission point to the obstacle can be calculated, i.e., s = 340 * t / 2.

[0095] In one embodiment, the chip determines whether the distance detected by the distance sensor 40 is less than or equal to a first threshold in order to obtain the folded state of the flexible display panel 10.

[0096] In one embodiment, such as Figure 10 As shown, the flexible display device 100 further includes a first support layer 141, a second support layer 142, a polarizing layer 15, a first adhesive layer 16, a first cover plate 17, a second adhesive layer 18, and a second cover plate 19. The first support layer 141 and the second support layer 142 are stacked on the back side of the substrate 11. The polarizing layer 15, the first adhesive layer 16, the first cover plate 17, the second adhesive layer 18, and the second cover plate 19 are stacked on the light-emitting side of the screen 11.

[0097] Understandably, when the bending region 10b is bent, the stress in the bending region 10b will change, and the resistance of the resistive switching element 121 will change according to the stress. For example, the material of the resistive switching element 121 can be a piezoresistive material, a piezoelectric material, a conductive elastomer, a liquid metal, graphene and its derivatives, carbon nanotubes, metal nanowires, etc. Piezoresistive materials deform their internal structure due to mechanical stress, thereby changing the electron transport path and altering the impedance (resistance value). Piezoresistive materials include monocrystalline silicon, polycrystalline silicon, copper-nickel alloys, nickel-chromium alloys, and conductive polymer composites, such as carbon nanotubes / polymers and graphene / PDMS (polydimethylsiloxane). Piezoelectric materials polarize under mechanical stress, accumulating surface charge and forming a potential difference, causing the impedance to change with stress. Piezoelectric materials include quartz, lead zirconate titanate, and polyvinylidene fluoride. Conductive elastomers are elastic polymers (such as silicone rubber and polyurethane) filled with conductive particles (such as silver, carbon black, and graphene). Deformation causes changes in the spacing between the fillers, leading to the connection or disconnection of conductive pathways and a step-like or continuous change in impedance. Typical materials for conductive elastomers include carbon black / silicone rubber composites and silver nanowire / PDMS (polydimethylsiloxane) composites. Liquid metals change shape during deformation, resulting in changes in the length or cross-sectional area of ​​conductive pathways, thus altering impedance; or they flow in microchannels, causing changes in contact area. Typical liquid metal materials include gallium indium tin alloys. The resistivity switching principle of graphene derivatives: When single-layer or multi-layer graphene is stretched or bent, the carbon atom lattice distortion leads to changes in the electronic band structure, resulting in a change in resistivity; or when a graphene film deforms on a substrate, cracks are generated, changing the contact resistance. The resistivity switching principle of carbon nanotubes: Single-walled or multi-walled carbon nanotubes undergo changes in electron orbital hybridization under stress, or the carbon nanotube network breaks / connects during stretching, leading to changes in impedance. Typical materials using carbon nanotubes include: carbon nanotube / polymethyl methacrylate composites and carbon nanotube films. The resistive switching principle of metal nanowires: When metal nanowires deform, the nanowire junctions break or re-connect, leading to a nonlinear change in impedance.

[0098] The flexible display panel 10 provided in this application embodiment has a resistive switching layer 12 provided in the bending region 10b, and the resistive switching layer 12 includes at least one resistive switching element 121. The resistance value of the resistive switching element 121 changes according to the bending state of the bending region 10b. In this way, when the flexible display panel 10 is folded or unfolded, the bending state of the bending region 10b changes, and the resistance value of the resistive switching element 121 also changes, which facilitates the flexible display device 100 to obtain the bending state in a timely manner, thereby controlling the display and screen-off of the flexible display panel 10 in a timely manner. Furthermore, by making the extension direction of the resistive switching element 121 intersect the bending axis C of the bending region 10b, it is not only beneficial to make the resistance value change of the resistive switching element 121 more sensitive, but also beneficial to improve the structural stability of the resistive switching element 121.

[0099] In one embodiment, the extension direction of the resistive variable 121 is perpendicular to the bending axis C of the bending region 10b. In other words, the extension direction of the resistive variable 121 is parallel to the first direction X.

[0100] It should be noted that, through experiments, the inventors discovered that when the extension direction of the resistive variable element 121 is parallel to the bending axis C of the bending region 10b, the strain value of the resistive variable element 121 is 0.2562%, and the detected voltage change is 0.05V; when the extension direction of the resistive variable element 121 is perpendicular to the bending axis C of the bending region 10b, the strain value of the resistive variable element 121 is 0.2843%, and the detected voltage change is 0.35V. It is evident that when the extension direction of the resistive variable element 121 is perpendicular to the bending axis C of the bending region 10b, the stress change and resistance change of the resistive variable element 121 are larger, facilitating a better acquisition of the bending state. Furthermore, the stress change causes less damage to the resistive variable element 121, and its characteristics do not undergo significant shifts, which is beneficial for improving the structural stability of the resistive variable element 121.

[0101] In one embodiment, the circuit principle for obtaining the bending state (or bending angle) through the resistance change of the resistive element 121 is as follows: Figure 5 As shown, R4 represents the impedance of resistor 121, offset represents the compensator, and Amplifier represents the amplifier. A preset voltage is applied across resistor 121, and the voltage change across resistor 121 and R3 is detected. After processing by the amplifier, the data is transmitted to the chip.

[0102] In one embodiment, such as Figure 2 and Figure 3 As shown, the bending region 10b has a first center line O1 parallel to its own extension direction; the first center line O1 passes through the resistive inverter 121. Here, it can also be understood that the orthogonal projection of the bending region 10b on the substrate 111 has a first center line O1 parallel to the second direction Y, and the first center line O1 passes through the orthogonal projection of the resistive inverter 121 on the substrate 111.

[0103] This not only makes the resistance value of the resistive variable 121 more sensitive, but also helps to improve the structural stability of the resistive variable 121.

[0104] In one embodiment, the first center line O1 passes through the center of the resistive inverter 121. Thus, on the one hand, the stress change of the resistive inverter 121 is relatively large, resulting in a large change in resistance, which facilitates better acquisition of the bending state; on the other hand, the stress change causes less damage to the resistive inverter 121, and the characteristics of the resistive inverter 121 do not undergo significant shifts, which is beneficial to improving the structural stability of the resistive inverter 121.

[0105] In one embodiment, the resistive inverter 121 is symmetrically arranged about the first center line O1. This results in two advantages: firstly, the resistive inverter 121 experiences greater stress and resistance variations, facilitating better acquisition of the bending state; secondly, stress variations cause less damage to the resistive inverter 121, preventing significant shifts in its characteristics and improving its structural stability.

[0106] In one embodiment, such as Figure 3 As shown, the resistive switching layer 12 includes multiple resistive switching elements 121, which are arranged at intervals along the axial direction of the bending axis C. This allows for more sensitive changes in resistance during bending, enabling better acquisition of the bending (or folding) state.

[0107] In one embodiment, such as Figure 4 As shown, the resistive variable element 121 includes a first extension 1211, a second extension 1212, and an outward protrusion 1213. The first extension 1211 and the second extension 1212 are arranged at intervals along a first direction X. The outward protrusion 1213 is provided on the same side of the first extension 1211 and the second extension 1212 along a second direction Y, and the outward protrusion 1213 connects the first extension 1211 and the second extension 1212. The second direction Y is perpendicular to the first direction X, and the second direction Y is parallel to the bending axis C of the bending region 10b.

[0108] Thus, on the one hand, the stress change of the resistive variable 121 is large, and the resistance value changes significantly, making it easier to obtain the bending state; on the other hand, the stress change causes less damage to the resistive variable 121, and the characteristics of the resistive variable 121 will not deviate significantly, which is beneficial to improving the structural stability of the resistive variable 121.

[0109] In one embodiment, the first extension 1211 has a second center line O2 parallel to the first direction X, and the second extension 1212 has a third center line O3 parallel to the first direction X, with the second center line O2 coinciding with the third center line O3. Thus, on the one hand, the stress change of the resistive inverter 121 is large, resulting in a large change in resistance, which facilitates better acquisition of the bending state; on the other hand, the stress change causes less damage to the resistive inverter 121, and the characteristics of the resistive inverter 121 do not undergo significant shift, which is beneficial to improving the structural stability of the resistive inverter 121.

[0110] In one embodiment, the first extension 1211 is symmetrically arranged about the second center line O2.

[0111] Thus, on the one hand, the stress change of the resistive variable 121 is large, and the resistance value changes significantly, making it easier to obtain the bending state; on the other hand, the stress change causes less damage to the resistive variable 121, and the characteristics of the resistive variable 121 will not deviate significantly, which is beneficial to improving the structural stability of the resistive variable 121.

[0112] In one embodiment, the second extension 1212 is symmetrically arranged about the third center line O3.

[0113] Thus, on the one hand, the stress change of the resistive variable 121 is large, and the resistance value changes significantly, making it easier to obtain the bending state; on the other hand, the stress change causes less damage to the resistive variable 121, and the characteristics of the resistive variable 121 will not deviate significantly, which is beneficial to improving the structural stability of the resistive variable 121.

[0114] In one embodiment, the orthographic projection of the protrusion 1213 onto the substrate 111 is symmetrical about the first centerline O1.

[0115] Thus, on the one hand, the stress change of the resistive variable 121 is large, and the resistance value changes significantly, making it easier to obtain the bending state; on the other hand, the stress change causes less damage to the resistive variable 121, and the characteristics of the resistive variable 121 will not deviate significantly, which is beneficial to improving the structural stability of the resistive variable 121.

[0116] In one embodiment, the orthographic projection of the first extension 1211 on the substrate 111 and the orthographic projection of the second extension 1212 on the substrate 111 are symmetrically arranged about the first centerline O1.

[0117] Thus, on the one hand, the stress change of the resistive variable 121 is large, and the resistance value changes significantly, making it easier to obtain the bending state; on the other hand, the stress change causes less damage to the resistive variable 121, and the characteristics of the resistive variable 121 will not deviate significantly, which is beneficial to improving the structural stability of the resistive variable 121.

[0118] In one embodiment, the array film layer 112 includes an active layer, and the resistive switching layer 12 is disposed in the same layer and with the same material as the active layer. In other words, as... Figure 6 As shown, the resistive switching layer 12 is located within the array film layer 112. Thus, the resistive switching layer 12 can be fabricated simultaneously with the active layer, which helps reduce fabrication costs.

[0119] In one embodiment, the array film layer 112 includes multiple metal layers, and the resistive switching layer 12 is disposed in the same layer and with the same material as one of the metal layers. In other words, as... Figure 6 As shown, the resistive switching layer 12 is located within the array film layer 112. Thus, the resistive switching layer 12 can be fabricated simultaneously with the metal layer, which helps reduce fabrication costs.

[0120] In one embodiment, such as Figure 7 As shown, the flexible display panel 10 also includes a touch electrode layer 13, and the resistive switching layer 12 is disposed in the same layer and with the same material as the touch electrode layer 13. In this way, the resistive switching layer 12 can be fabricated simultaneously when the touch electrode layer 13 is fabricated, which helps to reduce the fabrication cost.

[0121] In one embodiment, the resistive switching layer 12 is made of materials such as Mo, Ti, and Al. In one example, the resistive switching layer 12 is a Ti / Al / Ti stacked structure.

[0122] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0123] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A flexible display panel having a first flat area, a second flat area, and a bending area, the bending area connecting the first flat area and the second flat area; the flexible display panel having a folded state and an unfolded state; in the folded state, the first flat area and the second flat area are opposite to each other; In the unfolded state, the first straight region, the bent region, and the second straight region are arranged sequentially along a first direction; characterized in that, The flexible display panel includes: Base; An array film layer is disposed on one side of the substrate and located in the first flat region, the second flat region, and the bending region; A light-emitting device layer is disposed on one side of the array film layer and is located in the first flat region, the second flat region and the bending region; A resistive switching layer is located on one side of the substrate and in the bending region; the resistive switching layer includes at least one resistive switching element, the extension direction of which intersects the bending axis of the bending region; wherein the resistive switching element is configured such that its resistance value changes according to the bending state of the bending region.

2. The flexible display panel according to claim 1, characterized in that, The extension direction of the resistive element is perpendicular to the bending axis of the bending region.

3. The flexible display panel according to claim 1, characterized in that, The bending area has a first center line parallel to its own extension direction; the first center line passes through the resistive variable element; Optionally, the first center line passes through the center of the resistive element; Optionally, the resistive element is symmetrically arranged about the first center line.

4. The flexible display panel according to claim 1, characterized in that, The resistive switching layer includes multiple resistive switching elements, which are arranged at intervals along the axial direction of the bending axis.

5. The flexible display panel according to claim 1, characterized in that, The resistive element includes a first extension, a second extension, and an outward protrusion; The first extension and the second extension are arranged at intervals along the first direction, and the outward protrusion is provided on the same side of the first extension and the second extension along the second direction, and the outward protrusion connects the first extension and the second extension; the second direction is perpendicular to the first direction and parallel to the bending axis of the bending area; Optionally, the first extension has a second center line parallel to the first direction, and the second extension has a third center line parallel to the first direction, wherein the second center line coincides with the third center line.

6. The flexible display panel according to any one of claims 1-5, characterized in that, The array film layer includes an active layer, and the resistive switching layer is disposed in the same layer and made of the same material as the active layer.

7. The flexible display panel according to any one of claims 1-5, characterized in that, The array film layer includes multiple metal layers, and the resistive switching layer is disposed in the same layer and with the same material as one of the multiple metal layers.

8. The flexible display panel according to any one of claims 1-5, characterized in that, The flexible display panel also includes a touch electrode layer, and the resistive switching layer is disposed in the same layer and with the same material as the touch electrode layer.

9. A flexible display device, characterized in that, include: The first and second housings are rotatably connected; The flexible display panel as described in any one of claims 1-8 is disposed on the same side of the first housing and the second housing, wherein a first area of ​​the flexible display panel is connected to the first housing, and a second area of ​​the flexible display panel is connected to the second housing; The first display panel is located on the side of the first housing opposite to the flexible display panel.

10. The flexible display device according to claim 9, characterized in that, The flexible display device also includes a distance sensor; The distance sensor is located at the end of the first housing away from the bending area, or the distance sensor is located at the end of the second housing away from the bending area; the distance sensor is used to detect the distance between the end of the first housing away from the bending area and the end of the second housing away from the bending area.

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