Stretchable device and its manufacturing method

Abstract

This application provides a stretchable device and its manufacturing method, relating to the field of display technology, to reduce the risk of fracture of the bending strain layer during stretching. The stretchable device includes: a stretching region and a non-stretching region; a substrate; at least one bending strain layer located on one side of the substrate, covering the stretching region and the non-stretching region in a direction perpendicular to the plane of the substrate; wherein, the surface of the bending strain layer away from the substrate is the upper surface, and the surface closer to the substrate is the lower surface; the portion of the bending strain layer located in the stretching region is the stretching portion, the stretching portion including at least one stretching part, at least a portion of each stretching part having an arc-shaped bending shape, in the portion of the stretching part having an arc-shaped bending shape, the upper surface and the lower surface are concentric arcs, and the central angle corresponding to the arc of the upper surface is the same as the central angle corresponding to the arc of the lower surface.

Description

Technical Field

[0001] This invention relates to the field of display technology, and more specifically to a stretchable device and its manufacturing method. Background Technology

[0002] In display devices such as Organic Light Emitting Diode (OLED) and Quantum Light Emitting Diode (QLED), the light-emitting materials of their light-emitting elements are very sensitive to water and oxygen and are easily degraded under the influence of water and oxygen. Therefore, such display devices usually have an inorganic layer to isolate external water and oxygen in order to prevent water and oxygen from penetrating into the light-emitting elements.

[0003] However, inorganic materials do not have good tensile strength. For stretchable display devices, the inorganic layer is prone to fracture under stress during the stretching process, resulting in low reliability. Summary of the Invention

[0004] In view of this, this application provides a stretchable device and a method for manufacturing the same, which reduces the risk of fracture of the bending strain layer during the stretching process.

[0005] In a first aspect, embodiments of this application provide a stretchable device, comprising:

[0006] Tensioned zone and non-tensioned zone;

[0007] Substrate;

[0008] At least one bending strain layer is located on one side of the substrate, and in a direction perpendicular to the plane of the substrate, the bending strain layer covers the tensile region and the non-tensile region;

[0009] In the bending strain layer, the surface away from the substrate is the upper surface, and the surface closer to the substrate is the lower surface. The portion of the bending strain layer located in the tensile region is the tensile portion, which includes at least one tensile section. At least a portion of each tensile section is in an arc-shaped bending form. In the arc-shaped bending form of the tensile section, the upper surface and the lower surface are concentric circular arcs, and the central angle corresponding to the arc of the upper surface is the same as the central angle corresponding to the arc of the lower surface.

[0010] In this embodiment of the invention, in the stretching zone of the stretchable device, the structure of the stretching portion of the bending strain layer is adjusted so that at least a portion of its upper and lower surfaces are concentric arcs with the same central angle. When the stretchable device is stretched, the change in the central angle Δ between the upper and lower surfaces of this portion of the stretching portion, which is in an arc-shaped bending form, is significant. θ As the tension becomes more uniform, the strain on the upper and lower surfaces of this tensioned portion also tends to be uniform during the stretching process. The two surfaces tend to be stretched proportionally, which enables this tensioned portion to stretch evenly when stretched, thereby effectively improving the tensile properties of the bending strain layer and reducing the risk of the bending strain layer breaking during the stretching process.

[0011] Furthermore, the bending strain layer in this embodiment of the invention still completely covers the tensile and non-tensile regions, and the bending strain layer can effectively isolate water and oxygen in all tensile and non-tensile regions. Moreover, when this bending strain layer is used as an inorganic encapsulation layer in thin-film encapsulation, it is not necessary to encapsulate the light-emitting element separately, thus avoiding the reduction of the effect of stretching on the bending strain layer and avoiding the need to disconnect other film layers in the device, such as the passivation layer.

[0012] In one embodiment, the stretchable device further includes at least one elastic strain layer, wherein the elastic strain layer and the bending strain layer are stacked in a direction perpendicular to the plane of the substrate, and the elastic modulus of the elastic strain layer is smaller than that of the bending strain layer. Because the elastic strain layer has a lower elastic modulus and a larger elastic strain limit, it undergoes greater deformation during stretching, thereby allowing the bending strain layer to extend.

[0013] In one embodiment, the stretchable device further includes a light-emitting element located on one side of the substrate;

[0014] One or more of the bending strain layers are located on the side of the light-emitting element facing away from the substrate, and the bending strain layer on the side of the light-emitting element facing away from the substrate is reused as an inorganic encapsulation layer. In this case, the bending strain layer with an arc-shaped bending form effectively reduces the risk of the encapsulation layer breaking during the stretching process, thereby effectively improving the encapsulation reliability of the stretchable device and avoiding the light-emitting element from being corroded by water and oxygen to a greater extent.

[0015] In one embodiment, the stretchable device further includes a light-emitting element located on one side of the substrate;

[0016] One or more of the aforementioned bending strain layers are located on the side of the light-emitting element facing the substrate, and the bending strain layer on the side of the light-emitting element facing the substrate is reused as an inorganic passivation layer. This portion of the inorganic passivation layer can not only effectively isolate water and oxygen seeping in from the bottom of the display device and prevent molecules of the flexible material of the substrate from seeping into the light-emitting element, but also has good tensile properties to prevent the passivation layer from breaking during stretching. Moreover, in this embodiment of the invention, only the structure of the inorganic passivation layer needs to be adjusted to give it an arc-shaped curved surface, without the need for etching. Compared with the prior art, this avoids repeated etching and patterning of the passivation layer.

[0017] In one embodiment, the entire stretching portion is in an arc-shaped bending form. With this configuration, during the stretching process, the upper and lower surfaces of each stretching portion can be stretched proportionally, and the stretching portion can be stretched more uniformly to a greater extent, further improving the tensile performance of the bending strain layer.

[0018] Furthermore, the stretching portion includes a plurality of stretching sections, and the plurality of stretching sections include alternating first stretching sections and second stretching sections;

[0019] The first stretching portion bends away from the substrate, and the second stretching portion bends towards the substrate. The central angle corresponding to the first stretching portion is the same as the central angle corresponding to the second stretching portion.

[0020] In the above structure, on the one hand, the stretching part includes alternating first stretching parts and second stretching parts, and the stretching part is a continuous bending structure with a larger stretchable length. On the other hand, the central angles corresponding to the first stretching part and the second stretching part are the same. During the stretching process, the multiple stretching parts also undergo proportional stretching deformation, and the deformation of the multiple stretching parts is more uniform, which further optimizes the stretching effect of the bending strain layer.

[0021] Furthermore, in the stretched portion, the radius of the arc corresponding to the lower surface is r1, and the radius of the arc corresponding to the upper surface is r2.

[0022] When the entire stretched section is in an arc-shaped bending form, the radius of the arc corresponding to the lower surface is r1, and the radius of the arc corresponding to the upper surface is r2. The arc length of the lower surface is C1 = θ × r1, and the arc length of the upper surface is C2 = θ × r2. Here, the central angle θ in the formula is in radians, measured in rad. When the stretched section is stretched to its maximum extent, that is, when both the lower and upper surfaces are stretched to a plane, assuming the length of the lower surface remains unchanged after stretching (i.e., the length of the lower surface when stretched to a plane is still equal to C1), then there will be a length change of ΔC2 when the upper surface changes from a curved surface to a plane. This ΔC2 is the difference in arc length between the upper and lower surfaces, which is equal to θ × (r2 - r1). Under the maximum stretching state... When the tensioned section is not stretched to its maximum tension, the change in the central angle is Δθ, which is less than θ.

[0023] It can be seen that the larger θ is, The smaller the value, the smaller the change in length of the upper surface. Since the strain that the bending strain layer can withstand is limited, it can be made... satisfy: This reduces the change in length of the upper surface, thereby further reducing the risk of upper surface fracture.

[0024] Furthermore, 5nm < r2 - r1 < 1μm.

[0025] Setting the minimum value of r2-r1 to be greater than 5 nm avoids an excessively thin bending strain layer, ensuring it has sufficient thickness to isolate water and oxygen. Furthermore, setting the maximum value of r2-r1 to be less than 1 μm prevents r2-r1 from becoming too large. On the one hand, this ensures... The size is relatively small, so that the length change of the upper surface is small, and the radius r2 corresponding to the arc of the upper surface does not need to be set too large. Therefore, the height space required by the bending strain layer in the display device can be reduced, and the overall thickness of the display device can be reduced. On the other hand, it can also avoid the bending strain layer being too thick, making it easier to stretch under the action of the elastic strain layer.

[0026] In one embodiment, the bending radius of the first stretching portion is the same as that of the second stretching portion. The stretching ratio of the stretching portion is related to the central angle but not to the bending radius. Since the first stretching portion and the second stretching portion have the same central angle, they can still undergo proportional stretching and uniform deformation during the stretching process.

[0027] Furthermore, the stretchable device further includes at least one elastic strain layer, which includes a first elastic strain layer and a second elastic strain layer. The first elastic strain layer is located on the side of the bending strain layer facing away from the substrate, and the elastic modulus of the first elastic strain layer is less than that of the bending strain layer. The second elastic strain layer is located on the side of the bending strain layer facing the substrate, and the elastic modulus of the second elastic strain layer is less than that of the bending strain layer. The elastic modulus of the first elastic strain layer is equal to that of the second elastic strain layer.

[0028] When the central angle and bending radius corresponding to the first and second stretched portions are the same, the first and second stretched portions have the same bending shape in the unstretched state. Since the elastic modulus of the first and second elastic strain layers are equal, they undergo the same degree of deformation during the stretching process. Their effects on the stretching of the first and second stretched portions are consistent, thus making the stretched shapes of the first and second stretched portions tend to be the same, further optimizing the stretching effect of the bending strain layer.

[0029] In one embodiment, the bending radius of the first stretched portion is different from that of the second stretched portion. The stretching ratio of the stretched portion is related to the central angle but not to the bending radius. Since the first stretched portion and the second stretched portion have the same central angle, the first stretched portion and the second stretched portion undergo uniform deformation during the stretching process, thus optimizing the stretching effect of the bending strain layer.

[0030] Furthermore, the bending radius of the first stretching portion is smaller than that of the second stretching portion; the stretchable device further includes at least one elastic strain layer, the elastic strain layer including a first elastic strain layer and a second elastic strain layer, the first elastic strain layer is located on the side of the bending strain layer away from the substrate, the elastic modulus of the first elastic strain layer is smaller than that of the bending strain layer, the second elastic strain layer is located on the side of the bending strain layer facing the substrate, the elastic modulus of the second elastic strain layer is smaller than that of the bending strain layer, and the elastic modulus of the first elastic strain layer is greater than that of the second elastic strain layer.

[0031] When the bending radius of the first tension part is smaller than that of the second tension part, by adjusting the elastic modulus of the first elastic strain layer and the second elastic strain layer, the elastic modulus of the first elastic strain layer is made smaller, which can reduce the length change during the stretching process, increase the degree of resistance of the first elastic strain layer on the upper side of the first tension part to the stretching of the first tension part, and prevent the first tension part from breaking due to excessive deformation.

[0032] In one embodiment, the stretching portion includes a plurality of stretching sections, the plurality of stretching sections including alternating first stretching sections and second stretching sections, the first stretching sections being bent away from the substrate and the second stretching sections being bent toward the substrate;

[0033] The stretching portion further includes a rigid portion, the two ends of which are connected to the first stretching portion and the second stretching portion, respectively. When the stretchable device is not stretched, the plane of the rigid portion intersects with the plane of the substrate.

[0034] The rigid part refers to the part that is connected between the first tension part and the second tension part and is straight without bending. After the rigid part is set, it acts like a spring. When the stretchable device is stretched, the first tension part and the second tension part deform and the rigid part tilts. The tilted rigid part further increases the stretching length of the stretching part, thereby further increasing the tensile performance of the bending strain layer.

[0035] In one embodiment, the stretching portion includes a plurality of stretching sections, the plurality of stretching sections including alternating first stretching sections and second stretching sections, the first stretching sections being bent away from the substrate and the second stretching sections being bent toward the substrate;

[0036] The tangent where the vertex of the first stretching part is located is the first tangent, and the tangent where the vertex of the second stretching part is located is the second tangent;

[0037] The portion of the bending strain layer located in the non-stretched region is the non-stretched portion, which is situated between the first cross-section and the second cross-section.

[0038] If the non-stretched portion is connected to the top of the first stretching portion or the bottom of the second stretching portion, the thickness difference of the elastic strain layer on both sides of the non-stretched portion is large. During the stretching process, the non-stretched portion is easily deformed by the compression of the elastic strain layer on one side. However, by placing the non-stretched portion between the first and second sectional planes, the thickness difference of the elastic strain layer on both sides of the non-stretched portion is smaller, and the stress applied to the non-stretched portion by the two elastic strain layers tends to be consistent. The non-stretched portion is subjected to force balance, thus preventing the non-stretched portion from breaking under the action of the elastic strain layer.

[0039] In one embodiment, the stretchable device includes a plurality of bending strain layers, the stretchable device having a first cross section perpendicular to the plane of the substrate, wherein the central axes of the first stretch portions of the plurality of bending strain layers coincide on the first cross section, and the central axes of the second stretch portions of the plurality of bending strain layers coincide.

[0040] Furthermore, the bending radius of the first tensile portion in the plurality of bending strain layers is the same, and the bending radius of the second tensile portion in the plurality of bending strain layers is the same.

[0041] In some applications, such as thin-film encapsulation, a single-layer bending strain layer is insufficient to meet encapsulation performance requirements. This invention addresses this by incorporating multiple bending strain layers within a stretchable device, enabling the stacking of multiple layers while maintaining stretchability and improving its water and oxygen barrier properties. Furthermore, in this structure, the multiple bending strain layers share the same vertical morphology, resulting in uniform stretching among them during the stretching process. This leads to more uniform stretching of the overall structure and superior stretching performance of the stretchable device.

[0042] Furthermore, the stretchable device further includes at least one elastic strain layer, the elastic strain layer including a third elastic strain layer, the third elastic strain layer being located between two adjacent bending strain layers, and the elastic modulus of the third elastic strain layer being less than the elastic modulus of the bending strain layer.

[0043] The third elastic strain layer has a smaller modulus and a larger deformation during the stretching process. Thus, the deformation of the third elastic strain layer can be used to drive the stretching of the two adjacent bending strain layers during the stretching process.

[0044] In one embodiment, the stretchable device includes a plurality of bending strain layers, the stretchable device having a first cross section perpendicular to the plane of the substrate, wherein the central axes of the first stretch portions of the plurality of bending strain layers coincide on the first cross section, and the central axes of the second stretch portions of the plurality of bending strain layers coincide.

[0045] The bending strain layer closer to the substrate in two adjacent bending strain layers is the first bending strain layer, and the bending strain layer farther from the substrate is the second bending strain layer. In the first bending strain layer, the bending radius of the first tensile portion is R1, and the bending radius of the second tensile portion is R2, where R1 < R2. In the second bending strain layer, the bending radius of the first tensile portion is R1', and the bending radius of the second tensile portion is R2', where R1' > R2', and R1 = R2', R2 = R1'.

[0046] In this embodiment of the invention, by providing multiple bending strain layers in the stretchable device, the stacking of multiple bending strain layers can be achieved while maintaining stretchability, thereby improving its water and oxygen barrier properties. Furthermore, by ensuring that the bending radius of the tensile portion in two adjacent bending strain layers meets the aforementioned condition, the tensile performance can be improved while allowing adjacent bending strain layers to interlock, reducing the overall thickness required when the first and second bending strain layers are stacked. This reduces the impact of multiple bending strain layers on the overall thickness of the stretchable device, making it easier to achieve a thinner and lighter design for the stretchable device.

[0047] Furthermore, the stretchable device further includes at least one elastic strain layer, the elastic strain layer including a fourth elastic strain layer and / or a fifth elastic strain layer, the fourth elastic strain layer being located on the side of the bending strain layer closest to the substrate facing the substrate, the elastic modulus of the fourth elastic strain layer being less than the elastic modulus of the bending strain layer, and the fifth elastic strain layer being located on the side of the bending strain layer furthest from the substrate facing away from the substrate, the elastic modulus of the fifth elastic strain layer being less than the elastic modulus of the bending strain layer;

[0048] The stretchable device further includes a filler layer located between two adjacent bending strain layers. The elastic modulus of the filler layer is greater than that of the fourth elastic strain layer and the fifth elastic strain layer, but less than that of the bending strain layer.

[0049] By adopting the above configuration, on the one hand, the hardness of the filler layer is higher than that of the elastic strain layer, which can better maintain the morphology of the two adjacent bending strain layers. On the other hand, the elastic modulus of the filler layer is lower than that of the bending strain layer, which avoids excessive hardness. During the stretching process, the filler layer still has a certain deformation, which in turn drives the bending strain layer to stretch.

[0050] In one embodiment, the stretching portion includes a first straight portion, a first corner portion, a second straight portion, a second corner portion, and a third straight portion connected in sequence.

[0051] Wherein, the plane containing the first straight portion intersects with the plane containing the substrate, the plane containing the second straight portion is parallel to the plane containing the substrate, and the plane containing the third straight portion intersects with the plane containing the substrate;

[0052] The first corner and the second corner are curved in an arc shape and the bending direction is the same;

[0053] The bending radius of the first corner is R3, and the bending radius of the second corner is R4; the stretchable device has a first cross section, which is perpendicular to the plane of the substrate. On the first cross section, there is a first connecting line between the first straight part and the third straight part, and the distance between the center point of the first connecting line and the neutral plane of the second straight part is L.

[0054]

[0055] When the bending radius of the first corner is R3 and the bending radius of the second corner is R4, satisfying the above range, the individual stretched portion as a whole is closer to an arc-shaped bending form. That is, the entire upper and lower surfaces of the stretched portion tend to be concentric arcs, thus making the stretched portion more uniformly stretched. Moreover, by designing the stretched portion with the above-mentioned structure having straight and corner portions, in the process of manufacturing the elastic strain layer and the bending strain layer, it is not necessary to make the surface of the elastic strain layer in the stretching area completely continuous in a bending form when processing the elastic strain layer, reducing the processing difficulty of the elastic strain layer and making it easier to achieve in terms of process.

[0056] In one embodiment, the stretchable device further includes a light-emitting element located on one side of the substrate, the light-emitting element being located in the non-stretchable region.

[0057] Because the bending strain layer in the stretching region has a certain morphology and is non-flat, if this non-flat bending strain layer is located on the side of the light-emitting element facing away from the substrate, it will affect the uniformity of the brightness of the light emitted by the light-emitting element, thus causing poor display problems such as moiré patterns. However, in this embodiment of the invention, by placing the light-emitting element in the non-stretching region, regardless of whether the bending strain layer is located on the side of the light-emitting element facing or facing away from the substrate, this portion of the film with its arc-shaped bending will not affect the light emitted by the light-emitting element, thereby effectively improving the moiré pattern phenomenon.

[0058] Based on the same inventive concept, embodiments of the present invention also provide a method for manufacturing a stretchable device, for manufacturing the above-mentioned stretchable device, comprising:

[0059] At least one bending strain layer is formed on the substrate, and the bending strain layer covers the tensile region and the non-tensile region in a direction perpendicular to the plane of the substrate;

[0060] In the bending strain layer, the surface away from the substrate is the upper surface, and the surface closer to the substrate is the lower surface. The portion of the bending strain layer located in the stretching region is the stretching portion. The stretching portion includes at least one stretching section. At least a portion of the stretching section is in an arc-shaped bending form. In the stretching section in the arc-shaped bending form, the upper surface and the lower surface are concentric circular arcs, and the central angle corresponding to the arc of the upper surface is the same as the central angle corresponding to the arc of the lower surface.

[0061] In the bending strain layer formed using the above-described manufacturing method, the bending strain layer has a tensile portion, and at least a portion of the tensile portion is in an arc-shaped bending form. For this arc-shaped bending portion, its upper and lower surfaces are concentric circular arcs, and the corresponding central angles of the two are the same. When the stretchable device is stretched, the change range of the corresponding central angles of the upper and lower surfaces of the arc-shaped bending portion tends to be consistent, and the upper and lower surfaces of the arc-shaped bending portion tend to be stretched proportionally. This uniform stretching of the tensile portion improves the tensile performance of the bending strain layer, reduces the risk of breakage during the stretching process, and thus improves the reliability of the bending strain layer in isolating external water and oxygen.

[0062] In one embodiment, the manufacturing method further includes:

[0063] An elastic strain layer to be processed is formed on the substrate. The elastic modulus of the elastic strain layer to be processed is less than that of the bending strain layer. Specifically, the elastic strain layer to be processed can be formed on the substrate by spin coating, coating or inkjet printing. Since the forming material of the elastic strain layer to be processed has self-leveling properties, the surface of the elastic strain layer facing away from the substrate is a smooth horizontal surface.

[0064] The elastic strain layer to be processed is processed to form an undulating surface in the tensile region; specifically, laser direct writing, nanoimprinting and other processes can be used to process the elastic strain layer.

[0065] The process of forming the bending strain layer includes:

[0066] The bending strain layer is formed on the processed elastic strain layer, and the undulating surface of the elastic strain layer is used to give the bending strain layer an arc-shaped bending shape. Attached Figure Description

[0067] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0068] Figure 1 This is a schematic diagram of a stretchable display device in the prior art;

[0069] Figure 2 This is a schematic diagram of the manufacturing process of a barrier membrane composite layer in the prior art;

[0070] Figure 3This is a comparative schematic diagram of the stretching of a stretching unit in the prior art;

[0071] Figure 4 This is a schematic diagram of another structure of a stretchable display device in the prior art;

[0072] Figure 5 for Figure 4 The diagram shows the film structure of the stretchable display device.

[0073] Figure 6 This is a schematic diagram of the encapsulation layer structure in the prior art;

[0074] Figure 7 This is a schematic diagram of the structure of the stretchable device provided in an embodiment of the present invention;

[0075] Figure 8 This is a comparative diagram of the stretching of the stretching portion provided in an embodiment of the present invention;

[0076] Figure 9 A process flow diagram of the elastic strain layer and bending strain layer provided in an embodiment of the present invention;

[0077] Figure 10 This is another structural schematic diagram of the stretchable device provided in an embodiment of the present invention;

[0078] Figure 11 This is a schematic diagram of another structure of the stretchable device provided in an embodiment of the present invention;

[0079] Figure 12 This is another comparative tensile diagram of the tensile portion provided in an embodiment of the present invention;

[0080] Figure 13 This is a schematic diagram of a bending strain layer provided in an embodiment of the present invention;

[0081] Figure 14 This is a schematic diagram of another structure of the bending strain layer provided in an embodiment of the present invention;

[0082] Figure 15 This is a schematic diagram of another structure of the bending strain layer provided in an embodiment of the present invention;

[0083] Figure 16 This is another structural schematic diagram of the bending strain layer provided in an embodiment of the present invention;

[0084] Figure 17 This is another structural schematic diagram of the bending strain layer provided in an embodiment of the present invention;

[0085] Figure 18 This is another structural schematic diagram of the bending strain layer provided in an embodiment of the present invention;

[0086] Figure 19 This is another structural schematic diagram of the bending strain layer provided in an embodiment of the present invention;

[0087] Figure 20 This is another structural schematic diagram of the bending strain layer provided in an embodiment of the present invention;

[0088] Figure 21 This is another process flow diagram of the elastic strain layer and bending strain layer provided in the embodiments of the present invention;

[0089] Figure 22 This is a schematic diagram of a light-emitting element provided in an embodiment of the present invention;

[0090] Figure 23 This is a schematic diagram of another structure of the light-emitting element provided in an embodiment of the present invention. Detailed Implementation

[0091] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0092] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0093] As described in the background section, to prevent water and oxygen from seeping into the light-emitting element, display devices incorporate an inorganic layer to isolate them from external water and oxygen. Taking the inorganic layer in the encapsulation structure of an OLED display device as an example, traditional display devices initially used glass covers for encapsulation. However, the high rigidity of glass covers resulted in a rigid display device, making bending or stretching impossible. Therefore, current display devices mostly utilize thin-film encapsulation. Thin-film encapsulation typically consists of alternating layers of organic and inorganic layers. Compared to cover encapsulation, thin-film encapsulation not only reduces the encapsulation thickness but also ensures the encapsulated film adheres tightly to the light-emitting element, resulting in superior encapsulation performance.

[0094] However, as described in the background section, inorganic materials do not possess good tensile strength. Ideally, the light-emitting element and thin-film encapsulation can be designed on the neutral surface of the display device to avoid stress during bending or stretching. But in practical applications, the stress on the inorganic layer in the thin-film encapsulation is unavoidable, thus posing a significant risk of fracture to the inorganic layer.

[0095] Therefore, two implementation methods have been proposed in the prior art:

[0096] In the first embodiment, Figure 1 This is a schematic diagram of a structure of a stretchable display device in the prior art, such as... Figure 1 As shown, the stretchable display device includes a substrate 101, a light-emitting element 102, a barrier film composite layer 103, and a stretchable layer 122 stacked together. The barrier film composite layer 103 is an encapsulation layer and includes alternating layers of decoupling layers 104 and inorganic barrier layers 105. The decoupling layers 104 and inorganic barrier layers 105 have a very soft and elastic wavy structure, thus the inorganic barrier layer 105 is considered to have stretchability. Specifically, the inorganic barrier layer 105 can be... Figure 2 It is formed on the mold 107 with a wavy surface shown, and the mold 107 can be removed later.

[0097] However, the inventors discovered through research that relying solely on a wave-shaped design is insufficient to effectively improve the tensile properties of the packaging structure: In the aforementioned wave-shaped structure, the inorganic barrier layer 105 has a uniform thickness in the direction perpendicular to the plane of the substrate 101, and the upper surface (the surface facing away from the substrate 101) and lower surface (the surface facing the substrate 101) of the inorganic barrier layer 105 are identical, with the upper surface considered to be obtained by translating the lower surface. Therefore, combining... Figure 3 The diagram showing the stretching comparison of the stretching unit illustrates that, for a single stretching unit 106 in the inorganic barrier layer 105, the central angle θ1 corresponding to the upper surface 108 and the central angle θ2 corresponding to the lower surface 109 in the stretching unit 106 are different, and therefore the change range of the central angles of the upper and lower surfaces is different during the stretching process.

[0098] According to the strain formula As can be seen, ε represents strain, θ represents the central angle, and Δθ represents the change in the central angle. The strains generated on the upper surface 108 and the lower surface 109 are different, and they have different stretching ratios. This causes the inorganic barrier layer 105 to not stretch uniformly during the stretching process, thus still having a significant risk of breakage. For example, when the inorganic barrier layer 105 is a 60nm alumina film, the barrier film composite layer 103 will break when the tensile strain is greater than 0.75%.

[0099] In the second implementation, Figure 4This is a schematic diagram of another structure of a stretchable display device in the prior art. Figure 5 for Figure 4 The schematic diagram of the film structure of the stretchable display device shown is as follows: Figure 4 and Figure 5 As shown, the stretchable display device includes a substrate 110, a first passivation layer 111, a second passivation layer 112, a display unit 113, and an encapsulation layer 114 stacked together.

[0100] The substrate 110 has a cutout portion 115, which divides the substrate 110 into an island-shaped portion 116 and a connecting portion 117. The display unit 113 is located on the island-shaped portion 116. When a tensile force is applied to the stretchable display device, the connecting portion 117 is more easily stretched than the island-shaped portion 116 because the connecting portion 117 is narrower. This makes the island-shaped portion 116 less prone to deformation during the stretching process.

[0101] In one structure, please see again Figure 5 The encapsulation layer 114 encapsulates each display unit 113 individually, and the second passivation layer 112 is broken at the junction between the island portion 116 and the connecting portion 117. In this structure, the encapsulation layer 114 does not extend to the connecting portion 117 to prevent the encapsulation layer 114 from being damaged when the connecting portion 117 is stretched.

[0102] Or, in another structure, Figure 6 This is a schematic diagram of the encapsulation layer structure in the prior art, such as... Figure 6 As shown, the encapsulation layer includes a first inorganic encapsulation layer 118, an organic encapsulation layer 119, and a second inorganic encapsulation layer 120 stacked together. The second inorganic encapsulation layer 120 extends from the island portion 116 to the connecting portion 117. Furthermore, the portion of the second inorganic encapsulation layer 120 located in the connecting portion 117 forms a bend 121, which prevents a break from extending from the connecting portion 117 to the island portion 116.

[0103] However, the inventors discovered that, for Figure 5 In the structure shown, the second passivation layer 112 itself has high hardness. By breaking the second passivation layer 112 at the junction of the island portion 116 and the connecting portion 117 to allow the encapsulation layer 114 to encapsulate the display unit 113 separately, the second passivation layer 112 on the connecting portion 117 will still break and penetrate into the display unit 113 during the stretching process, causing damage to the display unit 113 device. Moreover, for thin film deposition processes with good conformality, relying on the method of dividing the second passivation layer 112 to block the encapsulation film will limit the further application of advanced thin film encapsulation technology and is not conducive to the further development of thin film encapsulation technology.

[0104] And for Figure 6 The structure shown relies on the bending portion 121 to reduce the risk of damage to the encapsulation film, which has a high degree of uncertainty. Moreover, for display devices with high-density pixel arrays, it is highly likely to cause pixel failure.

[0105] Based on this, embodiments of the present invention provide a stretchable device, which may specifically be a stretchable display device. Figure 7 This is a schematic diagram of the structure of the stretchable device provided in an embodiment of the present invention, as shown below. Figure 7 As shown, the stretchable device includes: a stretchable area 1 and a non-stretchable area 2, wherein the non-stretchable area 2 is a region that does not have the ability to stretch, such as a pixel island, and the stretchable area 1 is a region that has the ability to stretch, such as a stretchable bridge.

[0106] The stretchable device also includes a substrate 3 and at least one bending strain layer 4, which is located on one side of the substrate 3 and covers the stretched region 1 and the non-stretched region 2 in a direction perpendicular to the plane of the substrate 3. The substrate 3 can be formed of materials such as polydimethylsiloxane (PDMS), polyethylene terephthalate (PET), or polyimide (PI). The bending strain layer 4 is an inorganic layer, specifically made of Al2O3 with an elastic modulus of 100–300 GPa or SiN with an elastic modulus of 100–300 GPa. x Material: SiO₂ with an elastic modulus of 40–100 GPa x Materials, and those composites or doped with ZnO and TiO x Al2O3, SiN x and SiO x The formation of inorganic materials.

[0107] In the bending strain layer 4, the surface furthest from the substrate 3 is the upper surface 5, and the surface closest to the substrate 3 is the lower surface 6. The portion of the bending strain layer 4 located in the tensile region 1 is the tensile portion 7, which includes at least one tensile section 8. At least a portion of each tensile section 8 is in an arc-shaped bending form. In the arc-shaped bending portion of the tensile section 8, the upper surface 5 and the lower surface 6 are concentric circular arcs, and the central angle corresponding to the arc of the upper surface 5 is the same as the central angle corresponding to the arc of the lower surface 6. Figure 7 Let θ represent the central angles of the arcs corresponding to the upper surface 5 and the lower surface 6, let r1 represent the radius of the arcs corresponding to the lower surface 6, and let r2 represent the radius of the arcs corresponding to the upper surface 5.

[0108] In this embodiment of the invention, in the stretching zone 1 of the stretchable device, the structure of the stretching portion 8 of the bending strain layer 4 is adjusted so that at least a portion of its upper and lower surfaces are concentric arcs with the same central angle, combined with... Figure 8 The diagram shows a comparison of the stretching of the stretchable part. When the stretchable device is stretched, the change in the central angle Δθ of the upper surface 5 and the lower surface 6 of the stretchable part 8, which is in an arc-shaped bending form, tends to be consistent. Correspondingly, the strain experienced by the upper surface 5 and the lower surface 6 of this stretchable part 8 during the stretching process also tends to be consistent. The two surfaces tend to be stretched proportionally, thus enabling this stretchable part 8 to stretch evenly when stretched, thereby effectively improving the tensile performance of the bending strain layer 4 and reducing the risk of the bending strain layer 4 breaking during the stretching process.

[0109] Furthermore, in this embodiment of the invention, the bending strain layer 4 still completely covers the tensile region 1 and the non-tensile region 2, and the bending strain layer 4 can effectively isolate water and oxygen in all tensile regions 1 and non-tensile regions 2. Moreover, when the bending strain layer 4 is used as an inorganic encapsulation layer in thin-film encapsulation, it is not necessary to separately encapsulate the light-emitting element, thus avoiding the reduction of the effect of stretching on the bending strain layer 4 and avoiding the disconnection of other film layers in the device, such as the passivation layer.

[0110] In one implementation, please refer again. Figure 7 The stretchable device further includes at least one elastic strain layer 9. The elastic strain layer 9 and the bending strain layer 4 are stacked in a direction perpendicular to the plane of the substrate 3. The elastic modulus of the elastic strain layer 9 is less than the elastic modulus of the bending strain layer 4. Specifically, please refer again... Figure 7 An elastic strain layer 9 can be provided on both the side of the bending strain layer 4 facing the substrate 3 and the side facing away from the substrate 3. Since the elastic strain layer 9 has a low elastic modulus and a large elastic strain limit, the elastic strain layer 9 will generate a large deformation during the stretching process, thereby allowing the bending strain layer 4 to stretch.

[0111] It should be noted that the elastic strain layer 9 can be formed from materials with slightly higher elastic moduli, such as PET (2-4 GPa), PI (2-4 GPa), polymethyl methacrylate (PMMA) (2-4 GPa), and parylene (2-4 GPa). Alternatively, it can be formed from materials with lower elastic moduli, such as PDMS (0.8-4 MPa), agarose (0.2-0.5 MPa), polyurethane (PU) (5-100 MPa), and polybutylene adipate (PBAT) (20-60 MPa).

[0112] Furthermore, it should be noted that in the process of manufacturing the elastic strain layer 9 and the bending strain layer 4, the elastic strain layer 9 can be processed to form an undulating surface, thereby giving the bending strain layer 4 deposited on top an arc-shaped bending shape.

[0113] Specifically, Figure 9 The process flow diagram of the elastic strain layer 9 and the bending strain layer 4 provided in the embodiments of the present invention is as follows: Figure 9 As shown, the process of forming the elastic strain layer 9 and the bending strain layer 4 includes:

[0114] Step S1: The elastic strain layer 9 to be processed is formed on the substrate 3 by spin coating, coating or inkjet printing. Since the material forming the elastic strain layer 9 has self-leveling properties, the surface of the elastic strain layer 9 facing away from the substrate 3 is flat.

[0115] Step S2: The elastic strain layer 9 is processed using laser direct writing, nanoimprinting and other processes to form an undulating surface in the tensile region 1.

[0116] Step S3: A bending strain layer 4 is prepared on the elastic strain layer 9 with an undulating surface by processes such as vapor phase chemical deposition and atomic layer deposition, so that the tensile part 8 of the bending strain layer 4 is in an arc-shaped bending form.

[0117] Step S4: Form another elastic strain layer 9 on the substrate 3 by spin coating, coating or inkjet printing on the bending strain layer 4. If it is necessary to form another bending strain layer 4 on top of the elastic strain layer 9, then repeat steps S2 and S3. If no more bending strain layer 4 is to be set on top of the elastic strain layer 9, the self-leveling flat surface of the elastic strain layer 9 can be retained to achieve film planarization.

[0118] In one implementation, Figure 10 This is another structural schematic diagram of the stretchable device provided in the embodiment of the present invention, as shown below. Figure 10 As shown, the stretchable device also includes a light-emitting element 10 located on one side of the substrate 3. The light-emitting element 10 can be an organic light-emitting diode or a quantum dot light-emitting diode. One or more bending strain layers 4 are located on the side of the light-emitting element 10 facing away from the substrate 3, and the bending strain layer 4 on the side of the light-emitting element 10 facing away from the substrate 3 is reused as an inorganic encapsulation layer 11. In this case, the bending strain layer 4, which has an arc-shaped bending form, effectively reduces the risk of the encapsulation layer breaking during the stretching process, thereby effectively improving the encapsulation reliability of the stretchable device and further avoiding the light-emitting element 10 from being corroded by water and oxygen.

[0119] It should be noted that when the stretchable device also includes an elastic strain layer 9, the bending strain layer 4 acts as the inorganic encapsulation layer in the encapsulation layer, and the elastic strain layer 9 can act as the organic encapsulation layer in the encapsulation layer, thus forming a composite encapsulation structure including an inorganic encapsulation layer and an organic encapsulation layer.

[0120] Furthermore, it should be noted that when the bending strain layer 4 is reused as the inorganic encapsulation layer 11, the bending strain layer can be used not only in stretchable display devices but also in photovoltaic devices.

[0121] In existing display devices, before forming transistors and light-emitting elements 10, multiple passivation layers are typically formed on the substrate 3, for example... Figure 5 The multilayer first passivation layer 111 shown also includes an inorganic passivation layer formed of inorganic materials. In the prior art, to improve the tensile properties of this inorganic passivation layer, it is necessary to pattern each inorganic passivation layer in the stretching region. This results in a large number of etching and other patterning steps being added to the display device manufacturing process, increasing the difficulty of the process.

[0122] Based on this, in one implementation, Figure 11 This is another structural schematic diagram of the stretchable device provided in the embodiments of the present invention, as shown below. Figure 11 As shown, the stretchable device also includes a light-emitting element 10 located on one side of the substrate 3; one or more bending strain layers 4 are located on the side of the light-emitting element 10 facing the substrate 3, and the bending strain layer 4 on the side of the light-emitting element 10 facing the substrate 3 is reused as an inorganic passivation layer 12. This inorganic passivation layer 12 can not only effectively isolate water and oxygen seeping in from the bottom of the display device and prevent molecules of the flexible material of the substrate 3 from seeping into the light-emitting element 10, but also has good tensile properties to prevent the passivation layer from breaking during the stretching process. Moreover, in this embodiment of the invention, only the structure of the inorganic passivation layer 12 needs to be adjusted to make it have an arc-shaped curved surface, without the need for etching. Compared with the prior art, this avoids repeated etching and patterning of the passivation layer.

[0123] Furthermore, it should be noted that in this embodiment of the invention, when the stretchable device includes multiple bending strain layers 4, please refer again to... Figure 10 A portion of the bending strain layer 4 can be disposed on the side of the light-emitting element 10 facing away from the substrate 3, so that this portion of the bending strain layer 4 can be reused as an inorganic encapsulation layer 11, while the remaining portion of the bending strain layer 4 can be disposed on the side of the light-emitting element 10 facing the substrate 3, so that this portion of the bending strain layer 4 can be reused as an inorganic passivation layer 12.

[0124] In one implementation, please refer again. Figure 7 In the bending strain layer 4, the entire tensile part 8 is in an arc-shaped bending form, that is, the entire upper surface 5 and the entire lower surface 6 of the tensile part 8 are concentric circular arcs. With this setting, during the stretching process, the upper surface 5 and the lower surface 6 of each tensile part 8 can be stretched proportionally, and the tensile part 8 stretches more evenly, further improving the tensile performance of the bending strain layer 4.

[0125] It should be noted that, in combination Figure 12 The diagram shows another comparative stretching diagram of the stretching section 8. For a single stretching section 8, if the difference in arc length between the upper surface 5 and the lower surface 6 of the stretching section 8 is not considered, the bending radius of the stretching section 8 is equivalent to the radius r1 corresponding to the arc of the lower surface 6. Before stretching, the length of the stretching section 8 is equivalent to d. After stretching, the maximum stretch length that the stretching section 8 can achieve is equivalent to the arc length C1 of the lower surface 6, C1 = θ × r1, where the central angle θ in the formula is in radians, with the unit being rad. The maximum stretch ratio of the stretching section 8... It can be seen that the maximum stretch ratio of the stretching part 8 is only related to the central angle θ and is independent of the radius r1, that is, it is independent of the bending radius of the stretching part 8.

[0126] Based on this, in one implementation, Figure 13 This is a schematic diagram of a bending strain layer 4 provided in an embodiment of the present invention, as shown below. Figure 13 As shown, the stretching portion 7 includes multiple stretching portions 8, each comprising an alternately arranged first stretching portion 13 and second stretching portion 14. The first stretching portion 13 bends away from the substrate 3, while the second stretching portion 14 bends towards the substrate 3. The central angle corresponding to the first stretching portion 13 is the same as the central angle corresponding to the second stretching portion 14. Specifically, the central angle corresponding to the first stretching portion 13 refers to the central angle corresponding to the arc of the upper surface 5 and the arc of the lower surface 6 of the first stretching portion 13, and the central angle corresponding to the second stretching portion 14 refers to the central angle corresponding to the arc of the upper surface 5 and the arc of the lower surface 6 of the second stretching portion 14. Figure 13 The central angles corresponding to the first stretching part 13 and the second stretching part 14 are both represented by θ.

[0127] In the above structure, on the one hand, the stretching part 7 includes alternating first stretching part 13 and second stretching part 14. The stretching part 7 is a continuous bending structure and can be stretched to a greater length. On the other hand, the central angles corresponding to the first stretching part 13 and the second stretching part 14 are the same. During the stretching process, the multiple stretching parts 8 also undergo proportional stretching deformation. The deformation of the multiple stretching parts 8 is more uniform, which further optimizes the stretching effect of the bending strain layer 4.

[0128] In one embodiment, when the entire stretching portion 8 is in an arc-shaped bending form, the radius of the arc corresponding to the lower surface 6 in the stretching portion 8 is r1, the radius of the arc corresponding to the upper surface 5 is r2, the arc length of the lower surface 6 is C1 = θ × r1, and the arc length of the upper surface 5 is C2 = θ × r2, where the central angle θ in the formula is in radians and the unit is rad. When the stretching portion 8 is stretched to the maximum extent, that is, when both the lower surface 6 and the upper surface 5 are stretched to the plane, assuming that the length of the lower surface 6 remains unchanged after stretching, that is, the length of the lower surface 6 when stretched to the plane is still equal to C1, then there will be a length change of ΔC2 when the upper surface 5 changes from a curved surface to a plane. This ΔC2 is the difference in arc length between the upper and lower surfaces, which is equal to θ × (r2 - r1). Under the maximum stretching state... When the stretching section 8 is not stretched to its maximum stretch state, the change in the central angle is Δθ, which is less than θ.

[0129] It can be seen that the larger θ is, The smaller the value, the smaller the change in length of the upper surface 5. Since the strain that the bending strain layer 4 can withstand is limited, it can be made... satisfy: This reduces the change in length of the upper surface 5, thereby further reducing the risk of breakage of the upper surface 5.

[0130] Furthermore, r2-r1 can be set to satisfy: 5nm < r2-r1 < 1μm. Setting the minimum value of r2-r1 to be greater than 5nm can prevent the bending strain layer 4 from being too thin, ensuring that it has sufficient thickness to isolate water and oxygen. Furthermore, setting the maximum value of r2-r1 to be less than 1μm can prevent r2-r1 from being too large. On the one hand, while ensuring… The size is relatively small, so that the length change of the upper surface 5 is small, and the radius r2 corresponding to the arc of the upper surface 5 does not need to be set too large. Therefore, the height space required for the bending strain layer 4 in the display device can be reduced, and the overall thickness of the display device can be reduced. On the other hand, the bending strain layer 4 can also be prevented from being too thick, making it easier to stretch under the action of the elastic strain layer 9.

[0131] In one implementation, Figure 14This is another structural schematic diagram of the bending strain layer 4 provided in an embodiment of the present invention, as shown below. Figure 14 As shown, the bending radius of the first stretching portion 13 is the same as the bending radius of the second stretching portion 14. The bending radius of the stretching portion 8 refers to the distance from the center of the circle to the neutral surface of the stretching portion 8. Figure 14 In the figure, the bending radius of the first stretching part 13 and the bending radius of the second stretching part 14 are both represented by R.

[0132] It should be noted that when the central angle and bending radius corresponding to the first stretching part 13 and the second stretching part 14 are the same, the radius corresponding to the arc of the lower surface 6 of the first stretching part 13 and the radius corresponding to the arc of the lower surface 6 of the second stretching part 14 are equal. Figure 14 In the figure, r1 is used to represent the radius of the arc corresponding to the upper surface 5 of the first stretching part 13 and the upper surface 5 of the second stretching part 14. Figure 14 In this case, r2 is used as the denoting unit.

[0133] Based on the above description, the stretching ratio of the stretching part is related to the central angle but not to the bending radius. Since the first stretching part 13 and the second stretching part 14 have the same central angle, the first stretching part 13 and the second stretching part 14 can still be stretched proportionally and undergo uniform deformation during the stretching process.

[0134] Furthermore, please see again Figure 14 The stretchable device further includes at least one elastic strain layer 9, which includes a first elastic strain layer 19 and a second elastic strain layer 20. The first elastic strain layer 19 is located on the side of the bending strain layer 4 facing away from the substrate 3, and the elastic modulus of the first elastic strain layer 19 is less than the elastic modulus of the bending strain layer 4. The second elastic strain layer 20 is located on the side of the bending strain layer 4 facing the substrate 3, and the elastic modulus of the second elastic strain layer 20 is less than the elastic modulus of the bending strain layer 4. The elastic moduli of the first elastic strain layer 19 and the second elastic strain layer 20 are equal.

[0135] When the central angle and bending radius of the first tensioned portion 13 and the second tensioned portion 14 are the same, the first tensioned portion 13 and the second tensioned portion 14 have the same bending shape in the unstretched state. Since the elastic modulus of the first elastic strain layer 19 and the second elastic strain layer 20 are equal, during the stretching process, the first elastic strain layer 19 and the second elastic strain layer 20 undergo the same degree of deformation. The two have the same degree of stretching effect on the first tensioned portion 13 and the second tensioned portion 14, so that the stretched shapes of the first tensioned portion 13 and the second tensioned portion 14 tend to be the same, further optimizing the stretching effect of the bending strain layer 4.

[0136] Based on the above description, since the stretch ratio of each stretching part 8 is determined only by its central angle, in another embodiment, Figure 15 This is another structural schematic diagram of the bending strain layer 4 provided in an embodiment of the present invention, as shown below. Figure 15 As shown, the bending radius of the first stretching part 13 and the bending radius of the second stretching part 14 can also be set differently. Figure 15 In the figure, the bending radius of the first stretching part 13 is represented by R1, and the bending radius of the second stretching part 14 is represented by R2, where R1≠R2.

[0137] It should be noted that when the central angles of the first stretching portion 13 and the second stretching portion 14 are the same but the bending radii are different, the radius r1 corresponding to the arc of the lower surface 6 of the first stretching portion 13 and the radius r1' corresponding to the arc of the lower surface 6 of the second stretching portion 14 are not equal, and the radius r2 corresponding to the arc of the upper surface 5 of the first stretching portion 13 and the radius r2' corresponding to the arc of the upper surface 5 of the second stretching portion 14 are also not equal. During the stretching process, the first stretching portion 13 and the second stretching portion 14 with the same central angle can also undergo uniform deformation, reducing the risk of fracture of the bending strain layer 4.

[0138] Furthermore, please see again Figure 15 The bending radius of the first stretching portion 13 is smaller than that of the second stretching portion 14. The stretchable device further includes at least one elastic strain layer 9, which includes a first elastic strain layer 19 and a second elastic strain layer 20. The first elastic strain layer 19 is located on the side of the bending strain layer 4 facing away from the substrate 3, and the elastic modulus of the first elastic strain layer 19 is smaller than that of the bending strain layer 4. The second elastic strain layer 20 is located on the side of the bending strain layer 4 facing the substrate 3, and the elastic modulus of the second elastic strain layer 20 is smaller than that of the bending strain layer 4. The elastic modulus of the first elastic strain layer 19 is greater than that of the second elastic strain layer 20.

[0139] When the bending radius of the first tension part 13 is smaller than the bending radius of the second tension part 14, the elastic modulus of the first elastic strain layer 19 and the second elastic strain layer 20 are adjusted so that the elastic modulus of the first elastic strain layer 19 is smaller. This reduces the amount of length change during the stretching process and increases the degree of resistance of the first elastic strain layer 19 on the upper side of the first tension part 13 to the stretching of the first tension part 13, thus preventing the first tension part 13 from breaking due to excessive deformation.

[0140] Furthermore, it should be noted that the effect of the first elastic strain layer 19 and the second elastic strain layer 20 on the bending strain layer can also be adjusted by adjusting the thickness of the first elastic strain layer 19 and the second elastic strain layer 20.

[0141] In one implementation, Figure 16 This is another structural schematic diagram of the bending strain layer 4 provided in an embodiment of the present invention, as shown below. Figure 12 As shown, the stretching portion 7 includes multiple stretching portions 8, which include alternating first stretching portions 13 and second stretching portions 14. The first stretching portion 13 bends away from the substrate 3, and the second stretching portion 14 bends towards the substrate 3. The stretching portion 7 also includes a rigid portion 15, the two ends of which are connected to the first stretching portion 13 and the second stretching portion 14 respectively. When the stretchable device is not stretched, the plane of the rigid portion 15 intersects with the plane of the substrate 3.

[0142] It should be noted that the rigid part 15 refers to the straight section connected between the first tension part 13 and the second tension part 14, which is not bent. With the rigid part 15 provided, it acts like a spring. When the stretchable device is stretched, the first tension part 13 and the second tension part 14 deform, and the rigid part 15 tilts. The tilted rigid part 15 further increases the stretching length of the tension part 7, thereby further increasing the tensile properties of the bending strain layer 4. Furthermore, it should be noted that adding the rigid part 15 increases the overall height of the bending strain layer structure and further increases the magnitude of the strain in the elastic strain layer 9 during stretching. This allows the elastic strain layer 9 to exert a greater force on the tension part, preventing the tension part from breaking due to excessive deformation.

[0143] In one implementation, Figure 17 This is another structural schematic diagram of the bending strain layer 4 provided in an embodiment of the present invention, as shown below. Figure 17 As shown, the stretching portion 7 includes multiple stretching portions 8, which include alternating first stretching portions 13 and second stretching portions 14. The first stretching portion 13 bends away from the substrate 3, and the second stretching portion 14 bends towards the substrate 3. The cross-section where the vertex K1 of the first stretching portion 13 is located is the first cross-section 16, and the cross-section where the vertex K2 of the second stretching portion 14 is located is the second cross-section 17. The portion of the bending strain layer 4 located in the non-stretching region 2 is the non-stretching portion 18, which is located between the first cross-section 16 and the second cross-section 17. For example, the non-stretching portion 18 is connected to the end of the first stretching portion 13.

[0144] If the non-stretched portion 18 is connected to the top of the first stretching portion 13 or the bottom of the second stretching portion 14, the thickness difference of the elastic strain layer 9 on both sides of the non-stretched portion 18 is large. During the stretching process, the non-stretched portion 18 is easily deformed by the compression of the elastic strain layer 9 on one side. However, by placing the non-stretched portion 18 between the first cut surface 16 and the second cut surface 17, the thickness difference of the elastic strain layer 9 on both sides of the non-stretched portion 18 is smaller, and the stress applied to the non-stretched portion 18 by the two elastic strain layers 9 tends to be consistent. The non-stretched portion 18 is under force balance, thus preventing the non-stretched portion 18 from breaking under the action of the elastic strain layer 9.

[0145] In one implementation, Figure 18 This is another structural schematic diagram of the bending strain layer 4 provided in an embodiment of the present invention, as shown below. Figure 18 As shown, the stretchable device includes multiple bending strain layers 4. The stretchable device has a first cross-section, which is perpendicular to the plane of the substrate 3. Viewed from above, the stretching portion 8 is a strip-shaped structure, and the first cross-section is also perpendicular to the extension direction of the stretching portion 8. On the first cross-section, the central axes Q1 of the first stretching portions 13 in the multiple bending strain layers 4 coincide, and the central axes Q2 of the second stretching portions 14 in the multiple bending strain layers 4 coincide. Furthermore, the bending radii of the first stretching portions 13 in the multiple bending strain layers 4 are the same, and the bending radii of the second stretching portions 14 in the multiple bending strain layers 4 are the same. Figure 18 In the multiple bending strain layers 4, the bending radius of the first tensile portion 13 and the bending radius of the second tensile portion 14 are both represented by R. The central axis of the first tensile portion 13 passes through the center of the circle corresponding to the first tensile portion 13, and the central axis of the second tensile portion 14 passes through the center of the circle of the second tensile portion 14.

[0146] In some applications, such as when the bending strain layer 4 is used in thin-film encapsulation, a single bending strain layer 4 is insufficient to meet the encapsulation performance requirements. This embodiment of the invention, by incorporating multiple bending strain layers 4 within a stretchable device, achieves the stacking of multiple bending strain layers 4 while maintaining stretchability, thereby improving its water and oxygen barrier properties. Furthermore, in the aforementioned structure, the multiple bending strain layers 4 have the same vertical morphology, and during the stretching process, they are uniformly stretched. The overall structure composed of multiple bending strain layers 4 exhibits more uniform stretching, resulting in superior stretching performance of the stretchable device.

[0147] Furthermore, please see again Figure 18The stretchable device also includes at least one elastic strain layer 9, which includes a third elastic strain layer 21. The third elastic strain layer 21 is located between two adjacent bending strain layers 4. The elastic modulus of the third elastic strain layer 21 is less than that of the bending strain layer 4, so that the deformation of the third elastic strain layer 21 can further drive the stretching of the two adjacent bending strain layers 4 during the stretching process.

[0148] It should be noted that, in order to make multiple bending strain layers 4 have the same vertical morphology, the cross-sectional height of the third elastic strain layer 21 between two adjacent bending strain layers 4 is different at different positions. For example, the third elastic strain layer 21 has a smaller cross-sectional height h1 between the first tensile portion 13 and the second tensile portion 14 of two adjacent bending strain layers 4, while it has a larger cross-sectional height h2 between the two second tensile portions 14 of two adjacent bending strain layers 4.

[0149] Furthermore, it should be noted that, in conjunction with the above description of the process of elastic strain layer 9 and bending strain layer 4, in the process of the third elastic strain layer 21, laser direct writing, nanoimprinting and other processes can also be used to process the self-leveling surface of the third elastic strain layer 21, so that the third elastic strain layer 21 forms an undulating surface in the tensile region 1, and then another bending strain layer 4 is deposited on the third elastic strain layer 21.

[0150] In one implementation, Figure 19 This is another structural schematic diagram of the bending strain layer 4 provided in an embodiment of the present invention, as shown below. Figure 19 As shown, the stretchable device includes multiple bending strain layers 4. The stretchable device has a first cross section, which is perpendicular to the plane of the substrate 3. On the first cross section, the central axis P1 of the first stretching portion 13 in the multiple bending strain layers 4 coincides, and the central axis P2 of the second stretching portion 14 in the multiple bending strain layers 4 coincides.

[0151] The bending strain layer 4 on the side closer to the substrate 3 is the first bending strain layer 22, and the bending strain layer 4 on the side farther from the substrate 3 is the second bending strain layer 23. In the first bending strain layer 22, the bending radius of the first tensile portion 13 is R1, and the bending radius of the second tensile portion 14 is R2, where R1 < R2. In the second bending strain layer 23, the bending radius of the first tensile portion 13 is R1', and the bending radius of the second tensile portion 14 is R2', where R1' > R2', and R1 = R2', R2 = R1'.

[0152] In this embodiment of the invention, by providing multiple bending strain layers 4 in the stretchable device, the stacking of multiple bending strain layers 4 can be achieved while maintaining stretchability, thereby improving its water and oxygen barrier properties. On the other hand, by ensuring that the bending radius of the tensile portion 8 in two adjacent bending strain layers 4 meets the above conditions, the tensile performance can be improved while allowing two adjacent bending strain layers 4 to interlock, reducing the overall thickness required when the first bending strain layer 22 and the second bending strain layer 23 are stacked. This reduces the impact of multiple bending strain layers 4 on the overall thickness of the stretchable device, making it easier to achieve a thinner and lighter design for the stretchable device.

[0153] Furthermore, please see again Figure 19 The stretchable device further includes at least one elastic strain layer 9, which includes a fourth elastic strain layer 24 and / or a fifth elastic strain layer 25. The fourth elastic strain layer 24 is located on the side of the bending strain layer 4 closest to the substrate 3 facing the substrate 3, and the elastic modulus of the fourth elastic strain layer 24 is less than the elastic modulus of the bending strain layer 4. The fifth elastic strain layer 25 is located on the side of the bending strain layer 4 furthest from the substrate 3 facing away from the substrate 3, and the elastic modulus of the fifth elastic strain layer 25 is less than the elastic modulus of the bending strain layer 4.

[0154] The stretchable device also includes a filler layer 26 located between two adjacent bending strain layers 4. The elastic modulus of the filler layer 26 is greater than that of the fourth elastic strain layer 24 and the fifth elastic strain layer 25, but less than that of the bending strain layer 4. Specifically, the filler layer 26 can be formed using atomic layer deposition (ALD) growth materials, molecular layer deposition (MLD) growth materials, or some polymer materials with high modulus.

[0155] With the above configuration, on the one hand, the hardness of the filler layer 26 is higher than that of the elastic strain layer 9, so as to better maintain the morphology of the two adjacent bending strain layers 4. On the other hand, the elastic modulus of the filler layer 26 is lower than that of the bending strain layer 4, so as to avoid its hardness being too large. During the stretching process, the filler layer 26 still has a certain deformation, which in turn drives the bending strain layer 4 to stretch.

[0156] It should be noted that when the stretchable device includes two or more bending strain layers 4, it is only necessary to make the bending radius of the first stretching part 13 and the second stretching part 14 in a single bending strain layer 4 vary with the number of layers.

[0157] In one implementation, Figure 20 This is another structural schematic diagram of the bending strain layer 4 provided in an embodiment of the present invention, as shown below. Figure 20As shown, the stretching part 8 includes a first straight part 27, a first corner part 28, a second straight part 29, a second corner part 30 and a third straight part 31 connected in sequence.

[0158] Among them, the plane where the first straight part 27 is located intersects with the plane where the substrate 3 is located, the plane where the second straight part 29 is located is parallel to the plane where the substrate 3 is located, and the plane where the third straight part 31 is located intersects with the plane where the substrate 3 is located.

[0159] The first corner portion 28 and the second corner portion 30 are curved in an arc shape, and the curvature is in the same direction. That is, the upper surface 5 and the lower surface 6 of the first corner portion 28 are concentric arcs, and the central angle corresponding to the arc of the upper surface 5 is the same as the central angle corresponding to the arc of the lower surface 6. Similarly, the upper surface 5 and the lower surface 6 of the second corner portion 30 are concentric arcs, and the central angle corresponding to the arc of the upper surface 5 is the same as the central angle corresponding to the arc of the lower surface 6.

[0160] The bending radius of the first corner portion 28 is R3, and the bending radius of the second corner portion 30 is R4; the stretchable device has a first cross section, which is perpendicular to the plane of the substrate 3. On the first cross section, there is a first connecting line 32 between the first straight portion 27 and the third straight portion 31. The distance between the center point Y of the first connecting line 32 and the neutral plane of the second straight portion 29 is L.

[0161] R3, R4, and L satisfy:

[0162] When the bending radius of the first corner 28 is R3 and the bending radius of the second corner 30 is R4, which meets the above range, the individual stretching part 8 is closer to the arc-shaped bending shape as a whole. That is, the entire upper surface 5 and lower surface 6 of the stretching part 8 tend to be concentric arcs, so that the stretching part 8 tends to be stretched more evenly and smoothly.

[0163] In addition, it should be noted that, combined with Figure 21 The process flow diagrams for the elastic strain layer 9 and the bending strain layer 4 shown are consistent with... Figure 9 The process flow shown is similar. The above structure still uses the method of processing the elastic strain layer 9 to form an undulating surface, and then uses processes such as chemical vapor deposition and atomic layer deposition to prepare the bending strain layer 4 with straight parts and corner parts. By designing the tension part 8 to have the above-mentioned straight parts and corner parts, during the process of processing the elastic strain layer 9, it is not necessary to make the elastic strain layer 9 have a completely continuous bending shape on the surface of the tension region 1, which reduces the processing difficulty of the elastic strain layer 9 and makes the process easier to implement.

[0164] In one implementation, Figure 22 This is a schematic diagram of a structure of the light-emitting element 10 provided in an embodiment of the present invention. Figure 23 This is another structural schematic diagram of the light-emitting element 10 provided in an embodiment of the present invention, as shown below. Figure 22 and Figure 23 As shown, the stretchable device also includes a light-emitting element 10 located on one side of the substrate 3, and the light-emitting element 10 is located in the non-stretchable region 2.

[0165] Because the bending strain layer 4 in the stretching region 1 has a certain morphology and is non-flat, if the non-flat bending strain layer 4 is located on the side of the light-emitting element 10 facing away from the substrate, the bending strain layer 4 will affect the brightness uniformity of the light emitted by the light-emitting element 10, thus causing poor display problems such as moiré patterns. However, in this embodiment of the invention, by placing the light-emitting element 10 in the non-stretching region 2, regardless of whether the bending strain layer 4 is located on the side of the light-emitting element 10 facing the substrate 3 or the side facing away from the substrate 3, this part of the film layer with an arc-shaped bending shape will not affect the light emitted by the light-emitting element 10, thereby effectively improving the moiré pattern phenomenon.

[0166] Furthermore, the light-emitting element 10 can be made into a rigid light-emitting element, thereby further improving the overall elastic modulus of the non-stretched region 2, so that the non-stretched region 2 does not deform during the stretching process.

[0167] Based on the same inventive concept, embodiments of the present invention also provide a method for manufacturing a stretchable device, which is used to manufacture the aforementioned stretchable device, in conjunction with... Figure 7 The fabrication method includes: forming at least one bending strain layer 4 on a substrate 3, wherein the bending strain layer 4 covers the tensile region 1 and the non-tensile region 2 in a direction perpendicular to the plane of the substrate 3. The bending strain layer 4 can be specifically prepared by processes such as chemical vapor deposition or atomic layer deposition.

[0168] In the bending strain layer 4, the surface away from the substrate 3 is the upper surface 5, and the surface close to the substrate 3 is the lower surface 6. The portion of the bending strain layer 4 located in the tensile region 1 is the tensile portion 7. The tensile portion 7 includes at least one tensile part 8. At least a portion of the tensile part 8 is in an arc-shaped bending form. In the tensile part 8 in the arc-shaped bending form, the upper surface 5 and the lower surface 6 are concentric arcs, and the central angle corresponding to the arc of the upper surface 5 is the same as the central angle corresponding to the arc of the lower surface 6.

[0169] When the stretchable device is stretched, the change in the central angle Δθ of the upper surface 5 and the lower surface 6 of the stretchable part 8, which is in an arc-shaped bending form, tends to be consistent when the stretchable device is stretched. Correspondingly, the strain experienced by the upper surface 5 and the lower surface 6 of the stretchable part 8 during the stretching process also tends to be consistent. The two surfaces tend to be stretched proportionally, so the stretchable part 8 can be stretched evenly, thereby effectively improving the tensile performance of the bending strain layer 4 and reducing the risk of the bending strain layer 4 breaking during the stretching process.

[0170] Furthermore, combined Figure 9 and Figure 21 When the stretchable device includes an elastic strain layer 9, the manufacturing method further includes:

[0171] An elastic strain layer 9 to be processed is formed on the substrate 3. The elastic modulus of the elastic strain layer 9 to be processed is less than that of the bending strain layer 4. The elastic strain layer 9 to be processed is processed so that the processed elastic strain layer 9 forms an undulating surface in the tensile region 1.

[0172] Specifically, the elastic strain layer 9 to be processed can be formed on the substrate 3 by spin coating, coating, or inkjet printing. Since the material forming the elastic strain layer 9 has self-leveling properties, the surface of the elastic strain layer 9 facing away from the substrate 3 is flat. Subsequent processing of the elastic strain layer 9 can be performed using laser direct writing, nanoimprinting, or other processes. It should be noted that if nanoimprinting is used to process the elastic strain layer 9, curing is not required after its formation on the substrate 3.

[0173] Based on this, the process of forming the bending strain layer 4 includes: forming the bending strain layer 4 on the processed elastic strain layer 9, and using the undulating surface of the elastic strain layer 9 to make the bending strain layer 4 have an arc-shaped bending shape.

[0174] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0175] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A stretchable device, characterized by, include: Tensioned zone and non-tensioned zone; Substrate; At least one bending strain layer is located on one side of the substrate, and in a direction perpendicular to the plane of the substrate, the bending strain layer covers the tensile region and the non-tensile region; In the bending strain layer, the surface away from the substrate is the upper surface, and the surface closer to the substrate is the lower surface; the portion of the bending strain layer located in the stretching region is the stretching portion, and the stretching portion includes at least one stretching part. At least a portion of each stretching part is in an arc-shaped bending form. In the portion of the stretching part that is in an arc-shaped bending form, the upper surface and the lower surface are concentric circular arcs, and the central angle corresponding to the arc of the upper surface is the same as the central angle corresponding to the arc of the lower surface. The stretchable device further includes at least one elastic strain layer, wherein the elastic strain layer and the bending strain layer are stacked in a direction perpendicular to the plane of the substrate, and the elastic modulus of the elastic strain layer is less than that of the bending strain layer.

2. The stretchable device according to claim 1, characterized in that, The stretchable device also includes a light-emitting element located on one side of the substrate; One or more of the bending strain layers are located on the side of the light-emitting element facing away from the substrate, and the bending strain layers located on the side of the light-emitting element facing away from the substrate are reused as inorganic encapsulation layers.

3. The stretchable device according to claim 1, characterized in that, The stretchable device also includes a light-emitting element located on one side of the substrate; One or more of the bending strain layers are located on the side of the light-emitting element facing the substrate, and the bending strain layers on the side of the light-emitting element facing the substrate are reused as inorganic passivation layers.

4. The stretchable device according to claim 1, characterized in that, The entire stretching section has an arc-shaped bending shape.

5. The stretchable device according to claim 4, characterized in that, The stretching portion includes a plurality of stretching sections, and the plurality of stretching sections include alternating first stretching sections and second stretching sections. The first stretching portion bends away from the substrate, and the second stretching portion bends towards the substrate. The central angle corresponding to the first stretching portion is the same as the central angle corresponding to the second stretching portion.

6. The stretchable device according to claim 4, characterized in that, In the stretched section, the radius of the arc corresponding to the lower surface is r1, and the radius of the arc corresponding to the upper surface is r2. 0.002 < <0.

5.

7. The stretchable device according to claim 6, characterized in that, 5nm < r2 - r1 < 1μm.

8. The stretchable device according to claim 5, characterized in that, The bending radius of the first stretching part is the same as that of the second stretching part.

9. The stretchable device according to claim 8, characterized in that, The elastic strain layer includes a first elastic strain layer and a second elastic strain layer. The first elastic strain layer is located on the side of the bending strain layer away from the substrate, and the second elastic strain layer is located on the side of the bending strain layer facing the substrate. The elastic modulus of the first elastic strain layer is equal to that of the second elastic strain layer.

10. The stretchable device according to claim 5, characterized in that, The bending radius of the first stretching part is different from that of the second stretching part.

11. The stretchable device according to claim 10, characterized in that, The bending radius of the first stretching part is smaller than the bending radius of the second stretching part; The elastic strain layer includes a first elastic strain layer and a second elastic strain layer. The first elastic strain layer is located on the side of the bending strain layer away from the substrate, and the second elastic strain layer is located on the side of the bending strain layer facing the substrate. The elastic modulus of the first elastic strain layer is greater than that of the second elastic strain layer.

12. The stretchable device according to claim 1, characterized in that, The stretching portion includes a plurality of stretching sections, the plurality of stretching sections including alternating first stretching sections and second stretching sections, the first stretching sections being bent away from the substrate, and the second stretching sections being bent toward the substrate. The stretching portion further includes a rigid portion, the two ends of which are connected to the first stretching portion and the second stretching portion, respectively. When the stretchable device is not stretched, the plane of the rigid portion intersects with the plane of the substrate.

13. The stretchable device according to claim 1, characterized in that, The stretching portion includes a plurality of stretching sections, the plurality of stretching sections including alternating first stretching sections and second stretching sections, the first stretching sections being bent away from the substrate, and the second stretching sections being bent toward the substrate. The tangent where the vertex of the first stretching part is located is the first tangent, and the tangent where the vertex of the second stretching part is located is the second tangent; The portion of the bending strain layer located in the non-stretched region is the non-stretched portion, which is situated between the first cross-section and the second cross-section.

14. The stretchable device according to claim 5, characterized in that, The stretchable device includes a plurality of bending strain layers. The stretchable device has a first cross section, which is perpendicular to the plane of the substrate. On the first cross section, the central axes of the first stretch portions in the plurality of bending strain layers coincide, and the central axes of the second stretch portions in the plurality of bending strain layers coincide. Furthermore, the bending radius of the first tensile portion in the plurality of bending strain layers is the same, and the bending radius of the second tensile portion in the plurality of bending strain layers is the same.

15. The stretchable device according to claim 14, characterized in that, The elastic strain layer includes a third elastic strain layer, which is located between two adjacent bending strain layers.

16. The stretchable device according to claim 5, characterized in that, The stretchable device includes a plurality of bending strain layers. The stretchable device has a first cross section, which is perpendicular to the plane of the substrate. On the first cross section, the central axes of the first stretch portions in the plurality of bending strain layers coincide, and the central axes of the second stretch portions in the plurality of bending strain layers coincide. The bending strain layer closer to the substrate in two adjacent bending strain layers is the first bending strain layer, and the bending strain layer farther from the substrate is the second bending strain layer. In the first bending strain layer, the bending radius of the first tensile portion is R1, and the bending radius of the second tensile portion is R2, where R1 < R2. In the second bending strain layer, the bending radius of the first tensile portion is R1', and the bending radius of the second tensile portion is R2', where R1' > R2', and R1 = R2', R2 = R1'.

17. The stretchable device according to claim 16, characterized in that, The elastic strain layer includes a fourth elastic strain layer and / or a fifth elastic strain layer, wherein the fourth elastic strain layer is located on the side of the bending strain layer closest to the substrate facing the substrate, and the fifth elastic strain layer is located on the side of the bending strain layer furthest from the substrate facing away from the substrate. The stretchable device further includes a filler layer located between two adjacent bending strain layers. The elastic modulus of the filler layer is greater than that of the fourth elastic strain layer and the fifth elastic strain layer, but less than that of the bending strain layer.

18. The stretchable device according to claim 1, characterized in that, The stretching section includes a first straight section, a first corner section, a second straight section, a second corner section, and a third straight section connected in sequence; Wherein, the plane containing the first straight portion intersects with the plane containing the substrate, the plane containing the second straight portion is parallel to the plane containing the substrate, and the plane containing the third straight portion intersects with the plane containing the substrate; The first corner and the second corner are curved in an arc shape and the bending direction is the same; The bending radius of the first corner is R3, and the bending radius of the second corner is R4; the stretchable device has a first cross section, which is perpendicular to the plane of the substrate. On the first cross section, there is a first connecting line between the first straight part and the third straight part, and the distance between the center point of the first connecting line and the neutral plane of the second straight part is L. 0.3≤ ＜1，0.3≤ ＜1。 19. The stretchable device according to claim 1, characterized in that, The stretchable device further includes a light-emitting element located on one side of the substrate, wherein the light-emitting element is located in the non-stretchable region.

20. A method for manufacturing a stretchable device, characterized in that, For manufacturing a stretchable device as described in any one of claims 1 to 19, comprising: At least one bending strain layer is formed on the substrate, and the bending strain layer covers the tensile region and the non-tensile region in a direction perpendicular to the plane of the substrate; In the bending strain layer, the surface away from the substrate is the upper surface, and the surface closer to the substrate is the lower surface. The portion of the bending strain layer located in the tensile region is the tensile portion. The tensile portion includes at least one tensile section. At least a portion of the tensile section is in an arc-shaped bending form. In the tensile section in the arc-shaped bending form, the upper surface and the lower surface are concentric circular arcs, and the central angle corresponding to the arc of the upper surface is the same as the central angle corresponding to the arc of the lower surface. The manufacturing method further includes: An elastic strain layer to be processed is formed on the substrate, wherein the elastic modulus of the elastic strain layer to be processed is less than the elastic modulus of the bending strain layer; The elastic strain layer to be processed is processed so that the processed elastic strain layer forms an undulating surface in the tensile region; The process of forming the bending strain layer includes: The bending strain layer is formed on the processed elastic strain layer, and the undulating surface of the elastic strain layer is used to give the bending strain layer an arc-shaped bending shape.

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