Anisotropic conductive film, backplane structure and display device

Abstract

The application relates to an anisotropic conductive film, a back plate structure and a display device. The anisotropic conductive film comprises a plurality of target conductive regions; the plurality of target conductive regions are arranged one by one in correspondence with a plurality of pads on the driving back plate; wherein the conductive particle density of the target conductive region is greater than the conductive particle density of the remaining region outside the target conductive region. By arranging the target conductive region corresponding to the pad in a high conductive particle density mode, more contact points are formed between the chip electrode and the pad when pressure is applied, the problem of a small number of conductive particles between the pad and the chip electrode is avoided, the increased number of conductive particles leads to an increase in current density, the chip electrode of the Micro LED chip and the pad of the driving back plate form a more stable and efficient conductive path through the conductive particles of the target conductive region, thereby realizing reliable electrical connection.

Description

Technical Field

[0001] This application relates to the field of display technology, and in particular to an anisotropic conductive film, a backplane structure, and a display device. Background Technology

[0002] The fabrication process of Micro LED (Micro Light Emitting Diode) display devices mainly involves transferring mass-produced Micro LED chips onto a driver backplane and achieving electrical connection between the Micro LED chips and the driver backplane. Among these steps, the bonding technology between the electrodes of the Micro LED chips and the electrode pads on the driver backplane is crucial for achieving a reliable electrical connection between the Micro LED chips and the display backplane, directly affecting the electrical performance, optical performance, and product reliability of the Micro LED display device.

[0003] Currently, various techniques can be used to bond the electrodes of Micro LED chips to the electrode pads on the driver backplane, including eutectic bonding, flip-chip bonding, solid-state metal diffusion bonding, conductive adhesive bonding, and laser welding. Among these, anisotropic conductive film (ACF) bonding technology has become an important solution for bonding Micro LED chips to the driver backplane due to its low-temperature processing characteristics, suitability for flexible displays, and compatibility with large-scale transfer processes. However, in practical applications, traditional anisotropic conductive films are difficult to meet the precise conductivity requirements of the fine pixel structure of Micro LEDs, easily leading to poor electrode contact between the Micro LED electrodes and the substrate pads, thus causing dark spot defects in the display. Summary of the Invention

[0004] Therefore, it is necessary to address the aforementioned technical problems by providing an anisotropic conductive film, backplane structure, and display device that can improve the conductivity reliability of the electrodes of the Micro-LED chip and the electrode pads of the driving backplane.

[0005] In a first aspect, this application provides an anisotropic conductive film. This anisotropic conductive film is used to achieve electrical connection between the chip electrodes of a Micro-LED chip and the pads of a driving backplane. The anisotropic conductive film includes:

[0006] Multiple target conductive regions; each of the multiple target conductive regions is configured to correspond one-to-one with a plurality of pads on the drive backplane;

[0007] The conductive particle density in the target conductive region is greater than the conductive particle density in the remaining regions outside the target conductive region.

[0008] In one embodiment, a plurality of conductive particles are distributed along the outer edge of the target conductive region, with adjacent conductive particles abutting against each other.

[0009] In one embodiment, a plurality of conductive particles are distributed at the non-outer boundary of the target conductive region, adjacent conductive particles abutting each other, and conductive particles near the outer boundary of the target conductive region abutting each other with conductive particles at the outer boundary of the target conductive region.

[0010] In one embodiment, the remaining region outside the target conductive region is not configured with conductive particles.

[0011] In one embodiment, the projection of the target conductive region on the drive backplane completely covers the projection of the pad corresponding to the target conductive region on the drive backplane.

[0012] Secondly, this application also provides a drive backplane, which includes:

[0013] substrate;

[0014] The pads are disposed on the substrate; the surface of the pads facing away from the substrate is a non-smooth surface.

[0015] Thirdly, this application also provides a backplate structure, which includes:

[0016] Drive backplane;

[0017] As provided in the first aspect of this application, the anisotropic conductive film is attached to the surface of the drive backplate on the side where the pads are provided.

[0018] In one embodiment, the drive backplane includes:

[0019] substrate;

[0020] The pads are disposed on the substrate; the surface of the pads facing away from the substrate is a non-smooth surface.

[0021] In one embodiment, the non-smooth surface is provided with a plurality of grooves.

[0022] In one embodiment, the width of the groove is greater than the diameter of the conductive particle, and the depth of the groove is less than the diameter of the conductive particle.

[0023] Fourthly, this application also provides a display device that includes a back panel structure as provided in the third aspect of this application.

[0024] The aforementioned anisotropic conductive film, backplane structure, and display device configure the anisotropic conductive film into multiple target conductive regions and remaining regions outside the target conductive regions. Each target conductive region corresponds one-to-one with multiple pads on the driving backplane, and the conductive particle density in the target conductive regions is greater than the conductive particle density in the remaining regions outside the target conductive regions. The anisotropic conductive film of this application, by setting the target conductive regions corresponding to the pads to a high-density conductive particle arrangement, provides more contact points between the chip electrodes and the pads when pressure is applied, avoiding the problem of insufficient conductive particles between the pads and the chip electrodes. The increased number of conductive particles leads to an increase in current density, enabling the chip electrodes of the Micro LED chip and the pads of the driving backplane to form a more stable and efficient conductive path through the conductive particles in the target conductive regions, thereby achieving a reliable electrical connection. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments or conventional technologies of this disclosure, the accompanying drawings used in the description of the embodiments or conventional technologies will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a diagram illustrating the application environment of anisotropic conductive film in one embodiment.

[0027] Figure 2 This is a schematic diagram of the structure of an anisotropic conductive film in one embodiment;

[0028] Figure 3 This is a schematic diagram of the drive backplane in one embodiment;

[0029] Figure 4 This is a side view of a display panel in the related technology;

[0030] Figure 5 This is a top view of a display panel in the related technology;

[0031] Figure 6 In one embodiment Figure 2 The front view of the enlarged partial view of area A shown;

[0032] Figure 7 In one embodiment Figure 2 A side view of a magnified partial view of area A shown;

[0033] Figure 8 In one embodiment Figure 3 The front view of the enlarged partial view of area B shown;

[0034] Figure 9 In one embodiment Figure 3 The side view of the enlarged partial view of part B shown;

[0035] Figure 10 This is a schematic diagram of the backplane structure and the bonding of the Micro LED chip in one embodiment;

[0036] Figure 11 In one embodiment Figure 10 The image shows a magnified view of part E.

[0037] Explanation of reference numerals in the attached figures:

[0038] 100, Driver backplane; 101, Pad; 102, Groove; 200, Anisotropic conductive film; 201, Target conductive area; 202, Conductive particles; 300, Micro LED chip; 301, Chip electrode. Detailed Implementation

[0039] To facilitate understanding of this disclosure, a more complete description will now be given with reference to the accompanying drawings, which illustrate embodiments of the present disclosure. However, this disclosure can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure.

[0041] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various regions, layers, and / or portions, these regions, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one region, layer, or portion from another region, layer, or portion. Therefore, without departing from the teachings of this invention, the first region, layer, or portion discussed below may be referred to as the second region, layer, or portion.

[0042] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, the element or feature described as “below,” “under,” or “below” will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein will be interpreted accordingly.

[0043] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising / including” or “having,” etc., specify the presence of the stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. Meanwhile, in this specification, the term “and / or” includes any and all combinations of the associated listed items.

[0044] Embodiments of the invention are described herein with reference to cross-sectional views that serve as schematic diagrams of preferred embodiments (and intermediate structures) of this application, thus allowing for the anticipation of variations in the illustrated shapes due to, for example, manufacturing techniques and / or tolerances. Therefore, embodiments of the invention should not be limited to the specific shapes of the regions shown herein, but rather include shape deviations due to, for example, manufacturing techniques. The regions shown in the figures are substantially schematic, and their shapes do not represent the actual shapes of regions of the device, nor do they limit the scope of the invention.

[0045] The anisotropic conductive film of this application embodiment can be used to realize the electrical connection between the chip electrodes of a Micro-LED chip and the pads on the driving backplane, and improve the conductivity reliability between the Micro-LED chip electrodes and the pads. For example, please refer to... Figure 1The Micro LED display panel may include a driving backplane 100, an anisotropic conductive film 200, and a plurality of Micro LED chips 300 arranged in an array. The driving backplane 100 includes a substrate and pads 101 disposed on the substrate, and the anisotropic conductive film 200 is attached to the surface of the driving backplane 100 on the side where the pads 101 are disposed. The Micro LED chip 300 may be in the form of a flip chip, having a chip body and chip electrodes 301. The chip electrodes 301 include a chip anode and a chip cathode, both of which are disposed on the surface opposite to the light-emitting surface.

[0046] In practical applications, circuit wiring is completed on the substrate of the driving backplate 100, and metal pads 101 are formed on its uppermost layer. Subsequently, the Micro LED chip 300 is transferred to the driving backplate 100 through a transfer process, so that the chip anode and chip cathode of the Micro LED chip 300 correspond to the corresponding polarities of the pads 101. The electrical connection between the chip electrode 301 of the Micro LED chip 300 and the pads 101 depends on the anisotropic conductive film 200. After the anisotropic conductive film 200 is attached to the substrate of the driving backplate 100, by applying appropriate pressure towards the driving backplate 100 on the Micro LED chip 300, the pads 101, the conductive particles 202 in the anisotropic conductive film 200, and the chip electrode 301 of the Micro LED chip 300 are connected to form a conductive path.

[0047] In one embodiment, please refer to the reference. Figure 2 and Figure 3 This application provides an anisotropic conductive film 200, which is configured with a plurality of target conductive regions 201, and the plurality of target conductive regions 201 are configured to correspond one-to-one with the plurality of pads 101 of the drive backplane 100.

[0048] In this case, the conductive particle density of the target conductive region 201 in the anisotropic conductive film 200 is greater than the conductive particle density of the remaining regions outside the target conductive region 201.

[0049] The anisotropic conductive film 200 of this application embodiment may include an adhesive matrix and a plurality of conductive particles distributed within the adhesive matrix, wherein the adhesive matrix can provide electrical insulation and mechanical connection, and the conductive particles can provide electrical connection.

[0050] As an example, the adhesive matrix can be a thermosetting material, such as at least one of epoxy resin, polyurethane resin or acrylic resin.

[0051] As an example, the conductive particles can be spherical structures with a diameter of about 2 μm. The conductive particles can also be multilayer structures, which include polymer particles and a conductive film coated on the outer peripheral surface of the polymer particles with a predetermined thickness. For example, a two-layer structure with resin as the central layer and Ag as the conductive layer, or a three-layer structure with resin as the central layer, Ni as the first conductive layer and Au as the second conductive layer, or a three-layer structure with resin as the central layer, Ni as the conductive layer and an insulating layer as the outermost layer, etc.

[0052] The anisotropic conductive film 200 of this application embodiment can be divided in the film surface direction into a plurality of target conductive regions 201 corresponding one-to-one with the pads 101, and the remaining regions outside the target conductive regions 201. The plurality of target conductive regions 201 are independently and spaced apart in the anisotropic conductive film 200, and the conductive particle density of the target conductive regions 201 is greater than the conductive particle density of the remaining regions.

[0053] As an example, the multiple pads 101 in the driving backplate 100 can be arranged in a layout corresponding to the pixel arrangement of the screen, such as being arranged in pairs at intervals on one side surface of the substrate. Each pair of pads 101 can be electrically connected to the chip anode and chip cathode of the same Micro LED chip 300, respectively. One pad 101 corresponds to a target conductive region 201 in the anisotropic conductive film 200. In practical applications, the anisotropic conductive film 200 of this embodiment can be attached to the surface of the driving backplate 100 on the side where the pads 101 are provided according to the alignment mark, so that multiple target conductive regions 201 correspond one-to-one with the corresponding pads 101.

[0054] For example, in an RGB three-color Micro LED display panel, each pixel unit typically consists of three independent Micro LED chips 300 (R, G, and B) arranged at a fixed interval on the driving backplane 100. In this case, the pads 101 on the driving backplane 100 can be arranged in a matrix, with each pixel unit containing six pads 101 (each Micro LED chip 300 has two electrodes 301). The target conductive regions 201 of the anisotropic conductive film 200 in this embodiment are correspondingly arranged in a matrix, ensuring that each target conductive region 201 corresponds one-to-one with a pad 101, and that each target conductive region 201 is independently spaced.

[0055] As an example, the conductive particles in the remaining area of ​​the anisotropic conductive film 200 can be randomly and uniformly distributed in the adhesive matrix with a low conductive particle density. The conductivity of the anisotropic conductive film 200 can be determined by the number of conductive particles per unit area. Understandably, the low concentration of conductive particles in the remaining area prevents it from forming a conductive network in the film surface direction, resulting in insulating properties. However, the high conductive particle density arrangement in the target conductive area 201 increases the current density due to the increased number of conductive particles when pressure is applied. This provides more contact points between the chip electrode 301 and the pad 101 through the anisotropic conductive film 200 of this embodiment, thereby forming a more reliable conductive channel in the film thickness direction.

[0056] For example, the conductive particle density ρ1 of the target conductive region 201 and the conductive particle density ρ2 of the remaining region in the anisotropic conductive film 200 satisfy the following relationship: ρ1 > 0.04 ea / um², ρ2 < 0.04 ea / um².

[0057] For example, the conductive particle density ρ1 of the target conductive region 201 and the conductive particle density ρ2 of the remaining region in the anisotropic conductive film 200 satisfy the following relationship: ρ1 > 0.04 ea / um², and ρ2 is between 0.01 ea / um² and 0.02 ea / um². In this embodiment, the conductive particle density of the remaining region can be controlled between 0.01 ea / um² and 0.02 ea / um² to ensure that a continuous conductive network is not formed in the film surface direction, while maintaining certain mechanical properties and preventing inhomogeneity of the film structure. Preferably, the material of the conductive particles in the remaining region can be a metal or semiconductor material with high resistivity, such as high-resistivity silver-coated glass microspheres, indium tin oxide (ITO) particles, or doped polymer conductive particles, to further reduce its overall conductivity.

[0058] The aforementioned anisotropic conductive film 200 is configured with multiple target conductive regions and remaining regions outside the target conductive regions. Each target conductive region corresponds to a pad on the driving backplane, and the conductive particle density in the target conductive regions is greater than that in the remaining regions. In this embodiment, the anisotropic conductive film 200 sets the target conductive regions 201 corresponding to the pads 101 in a high-density conductive particle arrangement. This results in more contact points between the chip electrode 301 and the pads 101 when pressure is applied, avoiding the problem of insufficient conductive particles between the pads and the chip electrode 301. The increased number of conductive particles leads to increased current density, effectively reducing contact resistance. This allows the chip electrode 301 of the Micro LED chip 300 and the pads 101 of the driving backplane 100 to form a more stable and efficient conductive path through the conductive particles 202 of the target conductive regions 201, thereby achieving a reliable electrical connection.

[0059] In one embodiment, a number of conductive particles are distributed along the outer edge of the target conductive region, with adjacent conductive particles contacting each other.

[0060] The outer boundary of the target conductive region 201 refers to the boundary within the target conductive region 201 that is adjacent to the remaining region.

[0061] Please refer to Figure 4 and Figure 5 In related technologies, the Micro LED chip 300 is transferred onto a substrate pad 101 with a conventional anisotropic conductive film 400 attached. The conductive particles 401 in the conventional anisotropic conductive film 400 are randomly spaced within the adhesive matrix, and these particles (approximately 2 μm) are much smaller than the pads 101 (approximately 50 * 20 μm). When the Micro LED chip 300 is transferred onto the driving backplane 100, the chip electrode 301 and the pad 101 may experience a certain degree of offset, such as a slight offset in the horizontal (left-right) or vertical (up-down) direction. This reduces the overlap area between the chip electrode 301 and the pad 101, potentially leading to a smaller number of conductive particles between them.

[0062] Furthermore, because the conductive particles 401 inside the traditional anisotropic conductive film 400 have certain gaps during arrangement, some conductive particles 401 in the overlapping area of ​​the chip electrode 301 and the pad 101 may be squeezed out of the overlapping area due to pressure during the LED pressing process, resulting in insufficient or even missing conductive particles between the pad 101 and the chip electrode 301 (e.g. Figure 4 Central C area Figure 5 This uneven pixel illumination (in the D region) results in dark spots on the display screen.

[0063] In this embodiment of the anisotropic conductive film 200, a plurality of conductive particles 202 are distributed around the outer edge boundary of each target conductive region 201. The conductive particles 202 at the outer edge boundary are configured in a closely packed structure, in which adjacent conductive particles 202 are arranged in close contact, so that there is no obvious gap between adjacent conductive particles 202, thereby achieving physical contact between the conductive particles 202 at the outer edge boundary. In other embodiments, other internal regions of each target conductive region 201 that are not at the outer edge boundary can be randomly arranged at a predetermined density or arranged at regular intervals.

[0064] In this embodiment, by setting the conductive particles at the outer edge of the target conductive region to abut against each other, it is ensured to a certain extent that even if the chip electrode 301 and the pad 101 are misaligned, the overlapping area can cover at least part of the outer edge of the target conductive region 201, so that the chip electrode 301 can still form a reliable electrical connection with the pad 101. At the same time, this tightly packed structure helps to suppress excessive displacement of the conductive particles 202 when pressure is applied, further improving the stability of the conductive channel, thereby improving the overall connection reliability and electrical performance of the Micro LED device.

[0065] In one embodiment, a plurality of conductive particles are distributed at the non-outer boundary of the target conductive region, adjacent conductive particles abut against each other, and conductive particles near the outer boundary of the target conductive region abut against each other.

[0066] As an example, the conductive particles 202 within the target conductive region 201 can be arranged in an array, such as a regular rectangular array. Please refer to [reference needed]. Figure 6 In the direction of the film surface, each conductive particle 202 is in contact with multiple conductive particles around it. In this rectangular array arrangement, each conductive particle 202 at the non-outer boundary is in contact with four adjacent conductive particles 202 on the top, bottom, left and right.

[0067] In other embodiments, the conductive particles 202 within the target conductive region 201 can also be arranged in a honeycomb hexagonal array. In the hexagonal honeycomb array arrangement, each conductive particle 202 in the film surface direction is in contact with six surrounding conductive particles 202, which can further improve the diversity and uniformity of the conductive path.

[0068] For example, please refer to Figure 7 The conductive particles 202 are arranged in a single layer along the film thickness direction, meaning that the conductive particles 202 are distributed only in a single plane along the thickness direction and do not form a multi-layer stacked structure. This single-layer arrangement enables the conductive particles 202 to effectively establish a stable conductive path when under pressure, while avoiding the risk of uneven particle distribution or local short circuits that may be caused by multi-layer stacking.

[0069] In this embodiment, by setting the conductive particles in the target conductive area to abut against each other, it can be ensured that even if the chip electrode 301 and the pad 101 are offset, as long as there is an overlapping area between the chip electrode 301 and the pad 101, conductive particles 202 can be guaranteed, thereby further improving the stability of the electrical connection.

[0070] In one embodiment, the remaining area outside the target conductive area is not configured with conductive particles.

[0071] In this embodiment, the remaining area between the independently spaced target conductive regions 201 can be configured as an insulating area without conductive particles. That is, the conductive particles 202 inside the anisotropic conductive film 200 are only present at the pads 101 corresponding to the pixels, and are absent in other areas. Since increasing the number of conductive particles in the target conductive region 201 may increase the likelihood of the anisotropic conductive film 200 conducting in at least one horizontal direction, such horizontal conduction can easily lead to short circuits between pads. By omitting conductive particles in the remaining area, not only can the problem of short circuits between pads 101 caused by the tight arrangement of conductive particles 202 in the target conductive region 201 after compression be avoided, but the amount of conductive particles 202 used is also reduced, saving material costs.

[0072] In one embodiment, the projection of the target conductive region onto the driver backplane completely covers the projection of the pad corresponding to the target conductive region onto the driver backplane.

[0073] The area of ​​the target conductive region 201 is greater than or equal to the area of ​​the pad 101 corresponding to the target conductive region 201.

[0074] In practical applications, the anisotropic conductive film 200 of this application embodiment is attached to the surface of the drive backplate 100 on the side where the pads 101 are provided, according to the alignment mark. The projection of the target conductive area 201 on the drive backplate 100 completely covers the projection of the pad 101 corresponding to the target conductive area 201 on the drive backplate 100.

[0075] As an example, the area of ​​the target conductive region 201 is slightly larger than the area of ​​the pad 101 corresponding to the target conductive region 201. Setting the area of ​​the conductive particles 202 in the target conductive region 201 to be slightly larger than the pad 101 can compensate for the possible offset error when the anisotropic conductive film 200 is attached.

[0076] In other embodiments, the area of ​​the target conductive region 201 may also be equal to the area of ​​the pad 101 corresponding to the target conductive region 201.

[0077] In this embodiment, by reasonably controlling the range of the target conductive area 201, the positional deviation that may exist during the attachment process can be compensated, so that even if the Micro LED chip 300 is offset, the conductive path between its electrode and the pad 101 can still be guaranteed, which further improves the assembly accuracy and yield of the Micro LED display panel.

[0078] A second aspect of this application also provides a driving backplane, which includes a substrate and pads disposed on the substrate. As an example, a thin-film transistor (TFT) layer of TFT circuitry may be disposed on one side surface of the substrate. The substrate on which the TFT layer is disposed may be a glass substrate, a flexible synthetic resin-based substrate (e.g., polyimide (PI), polyethylene terephthalate (PET), polyethersulfone (PES), polyethylene naphthalate (PEN), or polycarbonate (PC)) or a ceramic substrate.

[0079] In one embodiment, the surface of the pad 101 facing away from the substrate can be a non-smooth surface.

[0080] Please refer to this again. Figure 4 and Figure 5 During the LED pressing process, some conductive particles 401 in the overlapping area of ​​the chip electrode 301 and the pad 101 may be squeezed out of the overlapping area due to pressure, resulting in insufficient or even missing conductive particles between the pad 101 and the chip electrode 301. In this embodiment, the surface of the pad 101 facing away from the substrate is set as a non-smooth surface to improve the retention ability of conductive particles 202.

[0081] As an example, the non-smooth surface of the pad 101 can be formed through roughening processes, such as chemical etching, laser texturing, sandblasting, or electroplating, to create micron- or nano-scale uneven structures on the pad surface. This roughened surface can provide better trapping capability for conductive particles 202 when the chip electrode 301 is pressed down, reduce the lateral overflow of conductive particles 202, improve the contact stability between the pad 101 and the chip electrode 301, and thus reduce the dark spot problem caused by the lack of conductive particles.

[0082] In one embodiment, the surface of the pad 101 facing away from the substrate may be formed by surface energy adjustment or electrostatic coating. For example, the surface energy of the pad 101 may be changed by treating the surface with plasma or coating it with self-assembled monolayers (SAMs) containing functional groups, or by coating the surface of the pad 101 with a conductive or semi-conductive coating to give it a weak electrostatic effect, thereby enhancing the adsorption capacity of the surface of the pad 101 for conductive particles 202.

[0083] In one embodiment, such as Figure 8 and Figure 9As shown, the surface of the pad 101 facing away from the substrate is a non-smooth surface, and a number of grooves 102 are provided on the non-smooth surface.

[0084] As an example, the size of the groove 102 is set such that the conductive particle 202 is partially embedded in the groove 102. Specifically, the width of the groove 102 is greater than the diameter of the conductive particle 202, and the depth of the groove 102 is less than the diameter of the conductive particle 202. For example, the conductive particle 202 can be a sphere with a diameter of about 2 μm. The opening diameter of the groove 102 is about 3 μm, and the depth is about 1 μm, so that the groove 102 can partially accommodate one conductive particle, but will not completely cover it. The conductive particle can still protrude from the groove 102 to ensure that the electrode can contact it.

[0085] As an example, the grooves 102 can be arranged in an array on the surface of the pads 101 facing away from the substrate, such as a rectangular array or a honeycomb array with a predetermined spacing.

[0086] In this embodiment, by providing several grooves 102 on the surface of the pad 101 away from the substrate, after the MicroLED chip 300 is transferred to the driving backplate 100, when pressure is applied to the MicroLED chip 300, the conductive particles 202 inside the anisotropic conductive film 200 are fixed in the grooves 102 of the pad and are not completely squeezed out of the overlapping area of ​​the pad 101 and the LED anode and cathode, which can improve the abnormality of dark spots to a certain extent.

[0087] Based on the same inventive concept, a third aspect of the present application also provides a backplate structure. The solution provided by this backplate structure is similar to the solution described in the above-described anisotropic conductive film or driving backplate. Therefore, the specific limitations of one or more backplate structure embodiments provided below can be found in the above-described limitations of the anisotropic conductive film or driving backplate, and will not be repeated here.

[0088] In one embodiment, a backplane structure is provided, which includes an anisotropic conductive film and a driving backplane as provided in the first aspect of the present application, wherein the anisotropic conductive film is attached to the surface of the driving backplane on the side where the pads are provided.

[0089] In one embodiment, a backplane structure is provided, the backplane structure including a driving backplane as provided in the second aspect of the present application embodiments above and an anisotropic conductive film, the anisotropic conductive film being attached to the surface of the driving backplane on the side where the pads are provided.

[0090] In one embodiment, a backplane structure is provided, such as Figure 10 and Figure 11As shown, the backplate structure includes an anisotropic conductive film 200 and a driving backplate 100 as provided in the first aspect of the embodiments of this application. The anisotropic conductive film 200 is attached to the surface of the driving backplate 100 on the side where the pads 101 are provided. The driving backplate 100 includes a substrate and pads 101 disposed on the substrate. The surface of the pads 101 facing away from the substrate is a non-smooth surface. A plurality of grooves 102 are provided on the non-smooth surface. The width of each groove 102 is greater than the diameter of the conductive particles 202, and the depth of each groove 102 is less than the diameter of the conductive particles 202.

[0091] In this embodiment, the conductive particles 202 of the target conductive region 201 corresponding to the pad 101 in the anisotropic conductive film 200 are closely arranged and are fixed in the groove 102 of the pad 101 under pressure.

[0092] A fourth aspect of this application also provides a display device, which includes a backplane structure as provided in the third aspect of this application, and further includes a Micro LED chip disposed on the backplane structure.

[0093] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0094] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. An anisotropic conductive film for realizing the electrical connection between the chip electrodes of a Micro-LED chip and the pads of a driving backplane, characterized in that, include: Multiple target conductive regions; The multiple target conductive areas are configured to correspond one-to-one with the multiple pads on the drive backplane; The conductive particle density in the target conductive region is greater than the conductive particle density in the remaining regions outside the target conductive region.

2. The anisotropic conductive film according to claim 1, characterized in that, The outer edge of the target conductive region is provided with a number of conductive particles, and adjacent conductive particles are in contact with each other.

3. The anisotropic conductive film according to claim 2, characterized in that, A number of conductive particles are distributed at the non-outer boundary of the target conductive region, with adjacent conductive particles abutting against each other, and conductive particles near the outer boundary of the target conductive region abutting against each other.

4. The anisotropic conductive film according to claim 1, characterized in that, The remaining region outside the target conductive region is not configured with conductive particles.

5. The anisotropic conductive film according to claim 1, characterized in that, The projection of the target conductive region onto the drive backplane completely covers the projection of the corresponding pad onto the drive backplane.

6. A backplate structure, characterized in that, include: Drive backplane; The anisotropic conductive film as described in any one of claims 1 to 5; the anisotropic conductive film is attached to the surface of the drive backplate on the side where the pads are provided.

7. The backplate structure according to claim 6, characterized in that, The drive backplate includes: substrate; The pads are disposed on the substrate; the surface of the pads facing away from the substrate is a non-smooth surface.

8. The backplate structure according to claim 7, characterized in that, The non-smooth surface has several grooves.

9. The backplate structure according to claim 8, characterized in that, The width of the groove is greater than the diameter of the conductive particle, and the depth of the groove is less than the diameter of the conductive particle.

10. A display device, characterized in that, Includes the backplate structure as described in any one of claims 6 to 9.

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