A flexible electroluminescent device

Abstract

The present application discloses a flexible electroluminescent device, which comprises a substrate, a first electrode layer, a light-functional layer, a second electrode layer and an encapsulation layer in sequence; a protective layer is provided between the substrate and the first electrode layer; the light-functional layer is composed of a plurality of light-emitting pixels; the first electrode layer is provided with a grid electrode corresponding to each light-emitting pixel; the protective layer is provided with a protection zone corresponding to the gap between the grid electrodes, and the tensile strength of the protection zone is less than the tensile strength of the grid electrode. The present application provides a protective layer between the substrate and the first electrode, and provides a protection zone with a tensile strength less than that of the grid electrode on the protective layer, so that when the device is subjected to an external deformation force, the protection zone is deformed preferentially, thereby reducing the occurrence of fractures on the first electrode layer.

Description

Technical Field

[0001] The present disclosure generally relates to the field of stretchable device technology, and more particularly to a flexible electroluminescent device. Background Art

[0002] In flexible OLED products, their functions require the products to be stretchable and curlable. When they are stretched and bent, the anode in the OLED is usually made of a transparent conductive oxide layer, which is very brittle and is easily broken during the stretching process, resulting in a typical connection break, which causes the screen to not light up. In the prior art, in order to solve the above problems, circuits are generally designed to reduce the occurrence of screen failure. Summary of the invention

[0003] In view of the above defects or deficiencies in the prior art, it is desirable to provide a flexible electroluminescent device, comprising a substrate, a first electrode layer, a light functional layer, a second electrode layer and an encapsulation layer in sequence; a protective layer is provided between the substrate and the first electrode layer;

[0004] The optical function layer is composed of a plurality of light-emitting pixels; the first electrode layer is provided with a grid electrode corresponding to each light-emitting pixel;

[0005] The protective layer is provided with a protection zone corresponding to the gap between the grid electrodes, and the tensile strength of the protection zone is smaller than the tensile strength of the grid electrodes.

[0006] According to the technical solution provided in the embodiment of the present application, the protective layer includes a polymer matrix, the polymer matrix in the protection zone is doped with microcapsules and a polymerization reaction catalyst, and the microcapsules are coated with a polymer precursor.

[0007] According to the technical solution provided in the embodiment of the present application, the microcapsules have at least 3 specifications of different sizes.

[0008] According to the technical solution provided in the embodiment of the present application, the microcapsule is made of cyclopentadiene dimer wrapped in urea-formaldehyde resin, and the polymerization reaction catalyst is a metal ruthenium-based catalyst.

[0009] According to the technical solution provided in the embodiment of the present application, the microcapsule is made of epoxy resin wrapped in urea-formaldehyde resin, and the polymerization reaction catalyst is a metal ruthenium-based catalyst.

[0010] According to the technical solution provided in the embodiment of the present application, the microcapsule is made of oligomeric organic siloxane wrapped in resin, and the catalyst is a supported platinum-based catalyst; the catalyst is supported on reinforcing particles or fiber fillers.

[0011] According to the technical solution provided in the embodiment of the present application, the portion of the protection layer corresponding to the grid electrode is a basic area, and the thickness of the protection area is less than 2 / 3 of the thickness of the basic area.

[0012] According to the technical solution provided in the embodiment of the present application, the protective layer is made of a stretchable elastomeric material, and the elastomeric material located in the protection area contains CF3 groups.

[0013] According to the technical solution provided in the embodiment of the present application, the grid electrode is provided with electrode leads, and the electrode leads extend from the gaps between the grid electrodes; the positions of the protective layer corresponding to the electrode leads are doped with conductive microcapsules.

[0014] According to the technical solution provided in the embodiment of the present application, the conductive microcapsule is made of conductive particles wrapped in resin.

[0015] According to the technical solution provided in the embodiment of the present application, the electrode lead has at least one extension direction, and a conductive microcapsule is provided in the protective layer corresponding to each extension direction of the electrode lead.

[0016] According to the technical solution provided in the embodiment of the present application, the grid electrode is provided with an electrode lead, and the electrode lead extends from the gap between the grid electrodes; the lead electrode is curved.

[0017] In the technical solution of the present application, a protective layer is provided between the substrate and the first electrode, and a protection zone with a tensile strength lower than that of the grid electrode is provided on the protective layer, so that when the device is subjected to external deformation force, the protection zone is deformed preferentially, thereby reducing the occurrence of fractures on the first electrode layer.

[0018] When the protective layer of the present application is formed by a self-healing material, the self-healing material includes microcapsules containing polymer precursors and polymerization reaction catalysts. Due to the doping of the self-healing material between the grid electrodes, the doped area has poor mechanical strength and will first break when stretched. This can reduce the stress in the normally luminous grid area and protect the first electrode layer from breaking. After the protection area is broken, the polymer precursor microcapsules are broken, causing the polymer precursor and the polymerization reaction catalyst to react and repair at the broken part, thereby greatly reducing the occurrence of screen anode breakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

[0020] Figure 1 This is a schematic cross-sectional view of the embodiment 1 of the present application;

[0021] Figure 2 This is a schematic diagram of the top view of the protective layer in Example 1 of the present application;

[0022] Figure 3This is a schematic diagram of the structure of Example 2 of the present application;

[0023] Figure 4 This is a schematic diagram of the structure of Example 3 of the present application;

[0024] Figure 5 and Figure 6 This is a structural diagram of Example 4 of the present application.

[0025] Numbers in the figure:

[0026] 10. Substrate; 20. First electrode layer; 30. Photofunctional layer; 40. Second electrode layer; 50. Encapsulation layer; 60. Protective layer; 21. Grid electrode; 62. Self-healing material; 22. Electrode lead; 63. Conductive microcapsule. DETAILED DESCRIPTION

[0027] The present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It is also necessary to explain that, for ease of description, only the parts related to the invention are shown in the accompanying drawings.

[0028] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0029] Example 1

[0030] Please refer to Figure 1 , this embodiment provides a flexible electroluminescent device, which includes a substrate 10, a first electrode layer 20, a light functional layer 30, a second electrode layer 40 and an encapsulation layer 50 in sequence; a protective layer 60 is provided between the substrate 10 and the first electrode layer 20;

[0031] The optical function layer 30 is composed of a plurality of light-emitting pixels; the first electrode layer 20 is provided with a grid electrode 21 corresponding to each light-emitting pixel;

[0032] Optionally, a protective layer 60 is provided on a side of the encapsulation layer 50 away from the second electrode layer 40 .

[0033] like Figure 2 As shown, the protective layer 60 is provided with a protection zone 61 corresponding to the gaps between the grid electrodes 21 , and the tensile strength of the protection zone is smaller than the tensile strength of the grid electrodes 21 .

[0034] Among them, the optical functional layer 30 includes a hole transport functional layer, a light-emitting layer and an electron transport functional layer; the substrate 10 and the encapsulation layer 50 are both made of flexible and stretchable materials, so that the electroluminescent device provided in this embodiment can be stretched and bent; among them, in this embodiment, the first electrode layer 20 is an anode and the second electrode layer is a cathode; in other embodiments, the first electrode layer 20 can also be a cathode and the second electrode layer can be an anode.

[0035] In this embodiment, the anode is made of a transparent conductive oxide material (such as ITO), which is brittle and consists of several grid electrodes. Therefore, in the prior art, when the device is bent or stretched, the grid electrode often breaks, thereby disconnecting the power supply of the pixel corresponding to the grid electrode of the optical functional layer, thereby causing the pixel to fail. In this embodiment, since the tensile strength of the protection zone is less than that of the grid electrode, when subjected to external force, the protection zone is deformed first, thereby reducing the occurrence of grid electrode breakage.

[0036] In this embodiment, the protection layer is implemented in the following manner:

[0037] like Figure 2 As shown, the protective layer includes a polymer matrix, and the polymer matrix in the protection zone is doped with microcapsules and a polymerization reaction catalyst, wherein the microcapsules contain a polymer precursor.

[0038] The polymer matrix may be, for example, a resin matrix, which is formed on the substrate 10 by coating. Specifically, the non-protected area of ​​the protective layer is defined as a base area, and the coating is combined by the following two steps:

[0039] Step 1: preparing a polymer matrix without doping microcapsules and polymerization catalysts, and coating it on a position corresponding to the base area on the substrate;

[0040] Step 2: Prepare a polymer matrix doped with microcapsules and polymerization catalysts, and apply it to the corresponding protected area on the substrate;

[0041] In other embodiments, the microcapsules and polymerization catalysts may also be subsequently coated separately on the surface of the polymer matrix and located at the required position of the protective layer, and the polymer matrix coated separately on the surface of the protective layer may penetrate into the polymer matrix material of the protective layer.

[0042] The microcapsules can be prepared by any of the following methods:

[0043] Mode 1: The microcapsule is made of cyclopentadiene dimer wrapped in urea-formaldehyde resin, and the polymerization catalyst is a metal ruthenium-based catalyst. In some embodiments, the metal ruthenium-based catalyst can also be wrapped in urea-formaldehyde resin to make capsules, and cyclopentadiene dimer is doped in the matrix.

[0044] Mode 2: The microcapsules are made of epoxy resin wrapped in urea-formaldehyde resin, and the polymerization catalyst is a metal ruthenium-based catalyst. In some embodiments, the metal ruthenium-based catalyst can also be wrapped in urea-formaldehyde resin to make capsules, and the epoxy resin is doped in the matrix, or the epoxy resin is directly used as the polymer matrix.

[0045] Mode 3: The microcapsule is made of oligomeric organic siloxane wrapped in resin, and the catalyst is a supported platinum-based catalyst supported on reinforcing particles or fiber fillers.

[0046] Due to the design of the microcapsule, the tensile strength of the protected area is concentrated. When subjected to external force, the microcapsule first ruptures, allowing the polymer precursor to flow out and react with the catalyst to self-repair the broken part.

[0047] In certain embodiments of the present application, the microcapsules have at least 3 different sizes.

[0048] When the light-emitting device is deformed under stress, large microcapsules will rupture first. When the tensile strength is not reached, resulting in the rupture of relatively small microcapsules, the relatively small microcapsules can be protected. During the next tensile stress, the relatively small microcapsules will rupture and be broken and repaired first when the device is stretched. The multi-level size setting of microcapsules increases the protection time of the protection area and improves the protection efficacy.

[0049] Example 2

[0050] like Figure 4 As shown, in the technical solution provided in this embodiment, based on Example 1, the tensile strength design of the protection zone is changed to the following manner:

[0051] The protective layer is formed by coating a resin matrix, and the portion of the protective layer corresponding to the grid electrode is a base region, such as Figure 4 As shown, the thickness of the protection zone in this embodiment is less than 2 / 3 of the thickness of the basic zone.

[0052] In this embodiment, a protective layer is formed by setting a protection area and a base area with significantly different thicknesses, so that under the action of external force, the relatively thin protection area is deformed first, thereby protecting the grid electrode corresponding to the base area and reducing the occurrence of fractures at the grid electrode.

[0053] In certain embodiments of the present application, the protective layer is made of a stretchable elastomeric material, and the elastomeric material located in the protected area contains CF3 groups; wherein, in this embodiment, the elastomeric material is a perfluoroelastomer synthesized using a copolymer of TFEMA and HFBA. Fluorinated polymers generally have high transparency due to their low refractive index. In addition, they are hydrophobic and chemically stable under aqueous conditions. The highly polar CF3 groups can also interact with each other to promote the self-healing process. In this polymer system, all monomers contain CF3 groups. Elastomers with ultra-high density CF3 groups to maximize dipole-dipole and ion-dipole interactions to achieve self-healing of the material.

[0054] Therefore, in this embodiment, when the relatively thin protection layer is deformed by preferential force, the protection layer can achieve self-repair due to the action of the CF3 groups in the protection layer.

[0055] Example 3

[0056] Based on Example 1, this embodiment further includes a conductive microcapsule. Figure 3 As shown, the grid electrode 21 is provided with an electrode lead 22, and the electrode lead 22 extends from the gap between the grid electrodes 21; the position corresponding to the electrode lead in the protective layer is doped with a conductive microcapsule 63, and the conductive microcapsule 63 is made of conductive particles wrapped in resin. The conductive particles can be, for example, graphene, and the resin that wraps the graphene can be, for example, urea-formaldehyde resin, epoxy resin, etc.

[0057] When the protection zone between the grid electrodes breaks, causing the electrode lead 22 to break, the conductive particles in the conductive microcapsule flow out after the break, and the electrode leads on both sides of the break are repaired, thereby repairing the power supply circuit of the anode and protecting the electrical connection of the screen.

[0058] In certain embodiments of the present application, the electrode lead has at least one extension direction, and a conductive microcapsule is provided in the protective layer corresponding to each extension direction of the electrode lead.

[0059] The conductive microcapsules can be formed in step 2 of forming the protective layer in Example 1, i.e., they are doped in the matrix together with the self-healing material for coating; preferably, they are formed in a separate step 3:

[0060] Step 3: Dope the conductive microcapsules into the matrix and coat them on the area corresponding to the electrode leads.

[0061] In other embodiments, the conductive microcapsules may also be subsequently coated separately at the required positions of the protective layer, and the conductive microcapsules coated separately on the surface of the protective layer may penetrate into the matrix material of the protective layer.

[0062] like Figure 3The electrode lead of each grid electrode shown in the figure has been bent once, so it has two extension directions, namely Figure 3 In the direction of arrow a and arrow b, conductive microcapsules are provided under the electrode leads in both directions. The electrode leads are easily broken in the direction perpendicular to their extension direction. Therefore, conductive microcapsules are provided in each extension direction to play a protective role in each direction that is prone to breakage.

[0063] Example 4

[0064] In this embodiment, based on the first embodiment, the electrode lead of the grid electrode 21 is designed to be curved, such as Figure 5 and Figure 6 As shown, the electrode lead can be in an S-shaped continuous bend or in a continuous alternating concave and convex shape.

[0065] The curved electrode lead design enhances the tensile strength of the electrode lead itself, thereby reducing the occurrence of electrode lead breakage.

[0066] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. A flexible electroluminescent device, characterized in that: It comprises a substrate, a first electrode layer, a light functional layer, a second electrode layer and a packaging layer in sequence; a protective layer is provided between the substrate and the first electrode layer; The optical function layer is composed of a plurality of light-emitting pixels; the first electrode layer is provided with a grid electrode corresponding to each light-emitting pixel; The protective layer is provided with a protection zone corresponding to the gap between the grid electrodes, and the tensile strength of the protection zone is smaller than the tensile strength of the grid electrodes; The protective layer comprises a polymer matrix, the polymer matrix in the protective area is doped with microcapsules and a polymerization catalyst, and the microcapsules are coated with a polymer precursor; The microcapsules have at least three different sizes. When the light-emitting device is deformed under stress, the large microcapsules rupture first. When the tensile strength is not reached to cause the relatively small microcapsules to rupture, the relatively small microcapsules can be protected. When the next tensile stress causes the relatively small microcapsules to rupture, the device stretches so that the protection area is broken and repaired first compared to the grid electrode.

2. The flexible electroluminescent device according to claim 1, characterized in that: The microcapsule is made of cyclopentadiene dimer wrapped in urea-formaldehyde resin, and the polymerization catalyst is a metal ruthenium-based catalyst; Alternatively, the microcapsules are made of epoxy resin wrapped in urea-formaldehyde resin, and the polymerization catalyst is a metal ruthenium-based catalyst; Alternatively, the microcapsule is made of oligomeric organic siloxane wrapped in resin, and the catalyst is a supported platinum-based catalyst; the catalyst is supported on reinforcing particles or fiber fillers.

3. The flexible electroluminescent device according to claim 1, characterized in that: The portion of the protection layer corresponding to the grid electrode is a basic region, and the thickness of the protection region is less than 2 / 3 of the thickness of the basic region.

4. The flexible electroluminescent device according to claim 1, characterized in that: The protective layer is made of a stretchable elastomeric material, and the elastomeric material in the protection area contains CF3 groups.

5. The flexible electroluminescent device according to any one of claims 1 to 4, characterized in that: The grid electrodes are provided with electrode leads, and the electrode leads extend from the gaps between the grid electrodes; the positions of the protective layer corresponding to the electrode leads are doped with conductive microcapsules.

6. The flexible electroluminescent device according to claim 5, characterized in that: The conductive microcapsule is made of conductive particles wrapped in resin.

7. The flexible electroluminescent device according to claim 6, characterized in that: The electrode lead has at least one extending direction, and a conductive microcapsule is provided in the protective layer corresponding to each extending direction of the electrode lead.

8. The flexible electroluminescent device according to claim 7, characterized in that: The grid electrodes are provided with electrode leads, and the electrode leads extend from the gaps between the grid electrodes; the electrode leads are bent.

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