LED array apparatus and manufacturing method therefor

Abstract

Provided in the present invention are an LED array apparatus and a manufacturing method therefor. The LED array apparatus comprises a driving base plate, a flexible film and a plurality of vertical structure LEDs, wherein first electrodes are provided on the outer side face of the driving base plate; the flexible film is bonded to the outer side face of the driving base plate, light-transmitting second electrodes are provided on the inner side face of the flexible film, and the second electrodes and the first electrodes are oppositely arranged and there are electrode overlapping areas therebetween; each vertical structure LED is sandwiched between the driving base plate and the flexible film and located in a corresponding electrode overlapping area; a third electrode is provided on the inner side face of each vertical structure LED, and the third electrode and a first electrode form electric conduction; and a fourth electrode is provided on the outer side face of each vertical structure LED, and the fourth electrode and a second electrode form electric conduction. The LED array apparatus not only has good bending resistance and good reliability, preventing failures during production, transportation and usage, but also involves easy processing and manufacturing, allowing for the fabrication of a relatively complex circuit pattern on a top circuit.

Description

LED array device and its manufacturing method Technical Field

[0001] This invention relates to the field of semiconductor display technology, and more specifically to LED array devices and their manufacturing methods. Background Technology

[0002] LED array devices use LEDs as controllable light-emitting array units, which can be used directly as displays or as dynamic backlights for LCD displays to achieve high brightness and high contrast display effects.

[0003] Vertical LEDs are LEDs with two electrodes (P-type and N-type) respectively positioned on opposite sides of the LED. LED array devices typically mount a large number of LEDs on a driver base plate in an array configuration. Using vertical LEDs in an LED array eliminates the need for the LEDs to be positioned at specific angles, thus significantly reducing manufacturing complexity.

[0004] However, one electrode of a vertical LED forms a bottom conductive connection with the circuit (such as a pad) on the driver base plate, while the other electrode is at the top. It is necessary to build a line that extends to the top of the LED (including the transparent electrode) to form a complete driver circuit. However, due to the large thickness of vertical LEDs (2-200μm), and the unevenness of its top caused by welding and bonding, building a line that extends to the top of the LED generally presents significant technological challenges.

[0005] In existing technologies, after setting vertical LEDs on a driving base plate, a planarization layer (such as a planarizing coating) is typically required. Top circuitry is then formed on this planarization layer using techniques like coating and photolithography. Holes also need to be drilled in the planarization layer to facilitate circuit connections between the top circuitry and the driving base plate. This makes the manufacturing process extremely complex. Furthermore, the uneven surface of the top layer results in very low precision in the top circuitry pattern, making it difficult to fabricate complex circuitry patterns. Additionally, the seam between the planarization layer and the vertical LEDs allows stress and strain to concentrate at the seam, potentially leading to breakage of the top circuitry. Therefore, this type of LED array device exhibits very poor bending resistance. Moreover, due to the protrusion of the vertical LEDs, the top circuitry is easily damaged by impacts or friction from external objects. Consequently, this type of LED array device not only has difficult-to-process top circuitry but is also highly prone to failure during production, transportation, and use, resulting in poor reliability. Summary of the Invention

[0006] The technical problem to be solved by this invention is to provide an LED array device and its manufacturing method. This LED array device not only has high reliability but is also easy to process and manufacture, reducing the design difficulty of LED circuits and enabling the creation of relatively complex circuit patterns on the top circuitry. The technical solution adopted is as follows:

[0007] An LED array device includes a driving base plate and a plurality of vertical structure LEDs. A first electrode is provided on the outer side of the driving base plate. The device is characterized in that: the LED array device further includes a flexible film bonded to the outer side of the driving base plate; a light-transmitting second electrode is provided on the inner side of the flexible film; the second electrode is disposed opposite to the first electrode and has an electrode overlap area; each of the vertical structure LEDs is sandwiched between the driving base plate and the flexible film and is located within a corresponding electrode overlap area; a third electrode is provided on the inner side of the vertical structure LED, and the third electrode and the first electrode are conductive; a fourth electrode is provided on the outer side of the vertical structure LED, and the fourth electrode and the second electrode are conductive.

[0008] The aforementioned LED array device utilizes a flexible film with a transparent second electrode on the outer side of the driving base plate. Multiple vertically structured LEDs are sandwiched between the driving base plate and the flexible film, allowing the fourth electrode on the outer side of each vertically structured LED to conduct electricity with its second electrode, thus forming the circuit of the LED array device. The flexible film can overcome the unevenness caused by the vertically structured LEDs through its own deformation and serves as a support for the second electrode, ensuring its smooth lead-out. Furthermore, placing the second electrode and its related circuitry on the flexible film reduces the risk of breakage. Simultaneously, the flexible film seals the driving circuitry internally, providing protection for it. Additionally, the flexible film can also incorporate some driving circuitry, thereby reducing the complexity of the driving circuitry design on the driving base plate.

[0009] The driving base plate can be a printed circuit board, glass plate, or plastic plate (such as polyimide film) with partial display driving lines (first driving lines). The first electrode is the output terminal of the first driving line, and the first electrodes are generally arranged in an array. The first driving line can be a static driving, dynamic driving, or active driving vertical structure LED display driving line. For example, when the driving base plate is a printed circuit board, the first driving line for static or dynamic driving of the vertical structure LED can be set on the circuit board, which is connected to each first electrode, and the first electrode can be a metal pad on the circuit board. When the driving base plate is a glass plate or plastic film, the first driving line can be an active driving circuit. The active driving circuit is a driving circuit based on thin film transistors (TFT, including α-Si, polycrystalline silicon, IGZO, etc. TFTs). The active driving circuit for driving vertical structure LED displays is generally a high-current driving circuit (similar to the active driving of OLED, which allows for a large output current). It can independently control the output current or voltage of each first electrode to control the light emission of its vertical structure LED. When the driving base plate is a glass plate or a plastic film, the first electrode can be an exposed conductor area or conductor block of metal or non-metal.

[0010] The flexible film may also be provided with a portion of the display driving circuitry, namely a second driving circuitry, and the second electrode is the output terminal of the second driving circuitry. For example, when the first driving circuitry is a row driving circuitry for dynamic driving of vertical LEDs, the second driving circuitry can together form a column driving circuitry for dynamic driving of vertical LEDs; while when the first driving circuitry is an active driving circuit, the second electrodery can be a common electrode shared by all LEDs, and the second driving circuitry can be an auxiliary circuitry or conductive film layer used to enhance the conductivity of the common electrodery.

[0011] The vertical structure LED can be a vertical structure LED wafer (or film) based on semiconductors such as GaAs, GaP, SiC, and GaN, and can be manufactured using existing vertical structure LED manufacturing processes. For example, its light-emitting semiconductor layer (such as a P-type layer, N-type layer, or quantum well layer) is generally epitaxially grown on an epitaxial substrate (such as sapphire), and finally peeled off from the epitaxial substrate using a lift-off process (such as laser lift-off). The P-electrode and N-electrode of the vertical structure LED wafer are located on two opposite sides of the film structure, where one side serving as the light-emitting surface is the fourth electrode (generally the N-electrode), and the other side is the third electrode (generally the P-electrode).

[0012] Generally, the third electrode can be an exposed surface of the semiconductor layer or a thin metal plating suitable for welding, such as a thin plating of gold, silver, copper, zinc, iron, or their alloys with a thickness of 5 nm to 1000 nm. The overall thickness of such a vertical LED structure is generally 1 to 20 μm. Alternatively, the third electrode can also be a thicker conductive substrate bonded to the aforementioned semiconductor layer, such as a metal plate or a conductive silicon substrate, thereby allowing the overall thickness of the vertical LED structure to exceed 100 μm.

[0013] The size of the vertical LED structure can be 5 to 500 μm (selected according to factors such as the array unit spacing), and its shape can be square, round, or other shapes.

[0014] In a preferred embodiment of the present invention, a portion of the flexible film is lifted by the corresponding vertical structure LED, forming a gap region with a gap between the flexible film and the driving base plate in the vicinity of the vertical structure LED. Generally, the gap region is considered to be the area of ​​the flexible film protruding near the vertical structure LED, formed by the flexible film extending laterally from the top of the vertical structure LED according to its own resistance to bending; or, it can be considered to be formed by the flexibility film's deformation having limits and not bending completely along the edge of the vertical structure LED. The vertical structure LED lifts the flexible film, causing it to be stretched taut at the top of each vertical structure LED, which is equivalent to the flexible film applying a certain pressure to one side of the driving base plate, thereby maintaining pressure between the fourth electrode and the second electrode, ensuring reliable conductivity. Based on the lateral extension of the flexible film, the gap region can be formed near the vertical structure LED, automatically preventing short circuits between the first and second electrodes.

[0015] As a further preferred embodiment of the present invention, the electrode overlapping region and the gap region have an overlapping area. The electrode overlapping region is relatively wide, encompassing not only the projected area of ​​the vertical LED structure but also extending beyond it. Within the gap region adjacent to the vertical LED structure, although the first and second electrodes overlap, they will not come into contact and short-circuit. By setting the electrode overlapping region to be relatively wide, the vertical LED structure can be positioned anywhere within the electrode overlapping region during manufacturing without strict alignment, which helps reduce the manufacturing difficulty of the LED array device.

[0016] As a further preferred embodiment of the present invention, the flexible film is bonded to the driving base plate by an adhesive; the first electrode and the second electrode are bonded together by adhesive filling the gap area. Thus, the adhesive maintains tensile stress in the vertical direction to retain the deformation of the flexible film, so that the vertical LED structure is compressed while the second and fourth electrodes maintain good conductivity.

[0017] As a further preferred embodiment of the present invention, the adhesive is also sandwiched between the fourth electrode and the second electrode, and conductive particles are mixed in the adhesive. The conductive particles are clamped by the fourth electrode and the second electrode to form a conductive connection between the fourth electrode and the second electrode.

[0018] Specifically, the conductive particles can be conductive metal particles or carbon particles, and their size is generally no larger than 1 / 2 of the thickness of the vertical LED structure. Preferably, the particle size is more than an order of magnitude smaller than the thickness of the vertical LED structure; for example, the conductive particles can be nanometer-sized particles, an order of magnitude smaller than the thickness of the vertical LED structure (micrometer level). Therefore, they can be clamped between the fourth and second electrodes to ensure conductive connection, while in the gap region they are generally not clamped to avoid short-circuiting the first and second electrodes. These conductive particles can generally be pre-mixed with adhesive and then applied to the drive base plate along with the adhesive.

[0019] As a further preferred embodiment of the invention, the adhesive further includes insulating spacer particles, which are sandwiched in the area outside the vertical LED structure to further maintain a gap between the flexible film and the driving base plate. This addition of insulating spacer particles prevents short circuits between the first and second electrodes due to excessive span.

[0020] Specifically, the insulating spacer particles are preferably microspheres or microrods made of materials such as plastic, glass, or insulating silicon, with a size preferably 0.2 to 0.8 times the thickness of the vertical LED structure. They are located outside the vertical LED structure, particularly embedded between the LED structures, to further maintain a gap between the flexible film and the driving base plate. The insulating particles can also be pre-mixed with adhesive and then applied to the driving base plate along with the adhesive. They are then scraped off from the top of the vertical LED structure using a specific scraping method (to prevent them from being on top of the LED structure).

[0021] As a further preferred embodiment of the invention, the gap region retains a negative pressure cavity. This allows the flexible membrane to be pressed firmly onto the vertical LED structure by atmospheric pressure.

[0022] In a preferred embodiment of the present invention, the surface of the second electrode is further provided with a soft conductive coating. Specifically, the soft conductive coating may be a conductive polymer coating (such as PEDOT:PSS) or other conductive adhesive layer (such as conductive acrylic) disposed on the second electrode. Thus, when the flexible film is pressed onto the vertical LED structure, the second electrode and the fourth electrode can form better conductivity.

[0023] In another preferred embodiment of the present invention, the fourth electrode of the vertical LED structure is provided with a conductive protrusion. Specifically, the conductive protrusion can be a metal bump, such as a gold bump or a tin alloy bump, disposed on the fourth electrode. The conductive protrusion ensures good contact between the fourth electrode and the second electrode.

[0024] As a preferred embodiment of the present invention, the flexible film has a deformation structure, which includes protrusions corresponding to the respective plurality of vertical structure LEDs. Thus, the flexible film can easily adapt to the protrusions at different positions of the plurality of vertical structure LEDs through its own deformation, ensuring good contact between the fourth electrode of the plurality of vertical structure LEDs and the second electrode of the flexible film.

[0025] In a preferred embodiment of the present invention, the flexible film is a plastic film with a thickness of no more than 0.4 mm. Specifically, the flexible film can be a plastic film such as PET (polyethylene terephthalate), PI (polyimide), CPI (transparent polyimide), or PC (polycarbonate) with a thickness of no more than 0.4 mm. Specifically, in order to improve flexibility to better accommodate multiple vertical LED protrusions, the thickness of the plastic film is preferably no more than 0.3 mm, especially no more than 0.2 mm; for example, a plastic film with a thickness of 0.05 to 0.2 mm can be selected. Generally, the plastic film is preferably a colorless and transparent plastic film, or it can also be a white transparent plastic film with optical diffusion properties.

[0026] In another preferred embodiment of the present invention, the flexible film is a transparent glass film with a thickness of no more than 0.2 mm. Generally, transparent glass films with a thickness of no more than 0.2 mm, especially no more than 0.1 mm, also have a certain degree of flexibility, thereby accommodating multiple vertical LED protrusions. Since the flexible film is a glass film, it has better heat resistance, making it easier to process with high-temperature processes to form a second electrode with better performance and the required driving circuitry.

[0027] In a preferred embodiment of the present invention, the second electrode is a transparent electrode formed of a transparent conductive oxide thin film. Specifically, the transparent conductive oxide thin film may be a film layer with conductivity and high transparency, such as indium tin oxide (ITO), aluminum zinc oxide (AZO), or indium zinc gallium oxide (IGZO), thereby giving the second electrode the advantages of good conductivity and high transparency.

[0028] As a preferred embodiment of the present invention, the second electrode is a transparent electrode made of a silver nanowire coating, which can prevent the second electrode from breaking when the flexible film is pressed by the vertical structure LED, thus making the yield of this vertical structure LED display higher.

[0029] As a preferred embodiment of the invention, each array unit is provided with a fixed number of vertical structure LEDs, particularly one vertical structure LED per array unit. Generally, each electrode overlap region corresponds to one array unit, thereby each electrode overlap region is provided with a fixed number of vertical structure LEDs, particularly one vertical structure LED.

[0030] In a preferred embodiment of the present invention, each array unit is provided with multiple vertical structure LEDs, which are randomly distributed in different array units. That is, the number of vertical structure LEDs in different array units or electrode overlap areas is not necessarily the same (but can have statistical characteristics, such as conforming to a Poisson distribution), and their positional distribution is also not necessarily the same. Therefore, the random distribution of vertical structure LEDs makes it easier to set the vertical structure LEDs onto the electrode overlap area through self-adhesion, self-assembly, or other methods, which is expected to achieve higher manufacturing efficiency.

[0031] As a further preferred embodiment of the present invention, the multiple vertical LEDs are loosely distributed within their electrode overlap area. Loose distribution means that there are gaps between the vertical LEDs within the electrode overlap area, rather than a close arrangement; for example, the projected area of ​​the vertical LEDs can be 30% to 70% of the area of ​​the electrode overlap area. This avoids the vertical LEDs clustering together, which would cause the flexible film to arch and fail to compress the central vertical LEDs.

[0032] As a preferred embodiment of the present invention, the driving base plate is provided with a first driving circuit, and the first electrode is the output terminal of the first driving circuit.

[0033] As a preferred embodiment of the present invention, the flexible membrane is provided with a second driving circuit, and the second electrode is the output terminal of the second driving circuit.

[0034] As a further preferred embodiment of the present invention, the second driving circuit is composed of a conductor layer with higher ductility than the second electrode. Specifically, the conductor layer can be a highly ductile metal film, especially a copper film (preferably with a thickness of not less than 1 μm), which is generally formed by techniques such as magnetron sputtering and electroplating, and the desired circuit pattern is formed by techniques such as photolithography. Alternatively, the conductor layer can also be a circuit layer printed from a low-resistance conductive adhesive, such as silver paste. By adding low-resistance circuitry, the probability of circuit breakage during bending and deformation of the flexible film can be reduced or eliminated, ensuring its conductivity.

[0035] In a preferred embodiment of the present invention, the first electrode is a solder pad, and the third electrode of the vertical LED is soldered onto the first electrode via a solder metal layer (such as a tin alloy). This results in a more robust connection between the vertical LED and the driving base plate, and improved conductivity. Displacement is less likely to occur during subsequent processing steps, ensuring high manufacturing yield.

[0036] As another preferred embodiment of the present invention, the third electrode of the vertical structure LED is electrically connected to the first electrode by pressing.

[0037] In another preferred embodiment of the present invention, the third electrode of the vertical structure LED is bonded to the first electrode by a conductive adhesive layer. Therefore, the vertical structure LED can be directly bonded to the first electrode by an adhesive method, avoiding the soldering process, and the first electrode does not need to be designed as a solder pad, making its manufacturing more convenient.

[0038] As a preferred embodiment of the present invention, the driving base plate is made of a flexible film. Therefore, the LED array device can be made into a flexible device. When the vertically structured LEDs are pressed together, both the driving base plate and the flexible film deform, rather than the deformation occurring entirely on the flexible film. This results in a more uniform stress distribution and improves the durability of the LED array device.

[0039] The present invention also provides a method for manufacturing the above-mentioned LED array device, characterized by comprising the following steps:

[0040] (1) Multiple first electrodes are set on the outer side of the driving base plate, and multiple vertical structure LEDs are set on the outer side of the driving base plate, and the third electrodes on the inner side of each vertical structure LED are respectively connected to the corresponding first electrodes to form a conductive path.

[0041] (2) First, apply adhesive to the outer side of the driving base plate and align the flexible film with the driving base plate so that the second electrode on the flexible film and the first electrode on the driving base plate form an electrode overlap area. Then, press the flexible film onto the driving base plate so that the flexible film is bonded to the driving base plate through adhesive and apply pressure so that the flexible film is pressed by the vertical structure LED so that the second electrode on the flexible film and the fourth electrode of the vertical structure LED form a conductive connection.

[0042] (3) Curing the adhesive;

[0043] (4) The flexible film is held in place by the vertical structure LED under the adhesive force of the adhesive.

[0044] The driving base plate may be pre-designed with overflow holes (such as through holes) or overflow channels, so that excess adhesive applied to the driving base plate in steps (2) and (3) (assuming sufficient adhesive was applied in step (2)) flows away from the overflow holes or overflow channels, ensuring that the final adhesive layer thickness is sufficient for the flexible film to effectively press against the vertical structure LED. For example, the average thickness of the final adhesive layer is less than the thickness of the vertical structure LED. Alternatively, the driving base plate may not need to be pre-designed with overflow holes or overflow channels. In step (2), by controlling the amount of adhesive applied, the average thickness of the adhesive on the plate surface after curing is less than the thickness of the vertical structure LED, so as to ensure that the final flexible film can effectively press against the vertical structure LED.

[0045] As a preferred embodiment of the present invention, the adhesive is a two-component adhesive, which is cured by natural reaction at room temperature in step (3).

[0046] As another preferred embodiment of the present invention, the adhesive is a thermosetting adhesive, which is cured by heating in step (3).

[0047] As another preferred embodiment of the present invention, the adhesive is a hot melt adhesive, which is first heated and melted into a liquid state in step (2) so as to press the flexible film onto the driving base plate so that the second electrode on the flexible film and the fourth electrode of the vertical structure LED are conductive; it is cured by cooling in step (3).

[0048] As a preferred embodiment of the present invention, in step (2), a flexible pressure plate (such as a silicone or foam pressure plate) is used to press the flexible film to achieve the pressure. When the flexible pressure plate applies pressure to the flexible film, it can adapt to the protrusions of the vertical LED structures at various locations, so that the flexible film is pressed tightly onto each vertical LED structure.

[0049] As a preferred embodiment of the present invention, in step (3), the adhesive is cured while the pressure is maintained; in step (4), the pressure is removed, and the flexible film is kept in a state where it is pressed against the vertical structure LED by the adhesive force of the adhesive.

[0050] As another preferred embodiment of the present invention, in step (2), the adhesive is left empty in the electrode overlap area; the flexible film is pressed onto the driving base plate under negative pressure and it forms an adhesive, and the area where the adhesive is left empty forms a negative pressure cavity, so that the flexible film is pressed by the atmosphere onto the vertical structure LED; in step (4), the negative pressure environment is removed, and the negative pressure cavity is pressed by the external atmosphere, so that the flexible film is generated and kept in a concave state in the electrode overlap area, which makes the second electrode pressed on the fourth electrode to form conductivity.

[0051] The above steps do not require curing the adhesive under pressure, thus increasing manufacturing efficiency. Generally, the adhesive can be a curable material, such as a two-component adhesive, hot melt adhesive, UV-curable adhesive, or thermosetting adhesive, which can be cured after step (3). Alternatively, the adhesive can also be a self-adhesive, which does not require curing after step (3).

[0052] Compared with the prior art, the present invention has the following advantages:

[0053] (1) This LED array device sets a flexible film with a light-transmitting second electrode on the outside of the driving base plate and sandwiches multiple vertical structure LEDs between the driving base plate and the flexible film, so that the fourth electrode on the outside of each vertical structure LED forms a conductivity with the second electrode, thus forming the circuit of the LED array device; the flexible film can overcome the uneven morphology caused by the vertical structure LED by its own deformation and serve as a support for the second electrode, ensuring that the second electrode can be smoothly led out, and the second electrode and its related circuits are set on the flexible film, making it less prone to breakage.

[0054] (2) This LED array device is based on the lateral extension of the flexible film, which can at least form a gap area near the vertical structure LED, automatically avoiding short circuits between the first electrode and the second electrode;

[0055] (3) The flexible membrane can also carry a certain driving circuit, thereby reducing the complexity of the driving circuit design on the driving base plate; the flexible membrane seals the driving circuit inside and can also form protection for the driving circuit. Attached Figure Description

[0056] Figure 1 is a schematic diagram of the structure of the LED array device provided in the preferred embodiment of the present invention.

[0057] Figure 2 is a partial enlarged view of the LED array device shown in Figure 1.

[0058] Figure 3 is a full sectional view of Figure 2.

[0059] Figure 4 is a schematic diagram of the manufacturing process of the LED array device provided in the preferred embodiment of the present invention, Example 1.

[0060] Figure 5 is a partial cross-sectional view of the LED array device provided in the preferred embodiment of the present invention, Example 2.

[0061] Figure 6 is a partial cross-sectional view of the LED array device provided in the preferred embodiment of the present invention, Example 3.

[0062] Figure 7 is a partial cross-sectional view of the LED array device provided in the preferred embodiment of the present invention, Example 4.

[0063] Figure 8 is a partial cross-sectional view of the LED array device provided in the preferred embodiment of the present invention, Example 5.

[0064] Figure 9 is a partial enlarged view of the LED array device provided in the preferred embodiment of the present invention, Example 6.

[0065] Figure 10 is a full sectional view of Figure 9.

[0066] Figure 11 is a partial enlarged view of the LED array device provided in the preferred embodiment of the present invention, Example 7.

[0067] Figure 12 is a full sectional view of Figure 11.

[0068] Figure 13 is a partial enlarged view of the LED array device provided in the preferred embodiment of the present invention, Example 8.

[0069] Figure 14 is a full sectional view of Figure 12.

[0070] Figure 15 is a schematic diagram of the manufacturing process of the LED array device provided in the preferred embodiment of the present invention, Example 8.

[0071] Figure 16 is a partial cross-sectional view of the LED array device provided in the preferred embodiment of the present invention, Example 9. Detailed Implementation

[0072] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0073] Example 1

[0074] As shown in Figures 1-3, this LED array device includes a driving base plate 1, a flexible film 2, and multiple vertical structure LEDs 3. A first electrode 10 is provided on the outer surface of the driving base plate 1. The flexible film 2 is bonded to the outer surface of the driving base plate 1, and a light-transmitting second electrode 20 is provided on the inner surface of the flexible film 2. The second electrode 20 is arranged opposite to the first electrode 10 and has multiple electrode overlap areas 100. The LED array device has multiple array units 50 constituting an array. The electrode overlap areas 100 correspond to the array units 50. Each electrode overlap area 100 is provided with a vertical structure LED 3. The vertical structure LED 3 is sandwiched between the driving base plate 1 and the flexible film 2. A third electrode 30 is provided on the inner surface of the vertical structure LED 3, and the third electrode 30 and the first electrode 10 are conductive. A fourth electrode 31 is provided on the outer surface of the vertical structure LED 3, and the fourth electrode 31 and the second electrode 20 are conductive.

[0075] In this embodiment, the driving base plate 1 is provided with a first driving line 11, and the first electrode 10 is the output terminal of the first driving line 11; the flexible film 2 is provided with a second driving line 21, which is composed of a conductor layer with higher ductility than the second electrode 20, and the second electrode 20 is the output terminal of the second driving line 21. The conductor layer can be a metal film with good ductility, especially a copper film (preferably with a thickness of not less than 1 μm), which is generally formed by magnetron sputtering, electroplating, or other techniques, and the required circuit pattern is formed by photolithography or other techniques. In addition, the conductor layer can also be a circuit layer printed from a low-resistance conductive adhesive, such as silver paste. By adding low-resistance circuits, the probability of circuit breakage when the flexible film 2 is bent and deformed can be reduced or eliminated, ensuring its conductivity.

[0076] The driving base plate 1 can be a printed circuit board, glass plate, or plastic plate (such as polyimide film) with partial display driving lines (first driving lines 11). The first electrode 10 is the output terminal of the first driving line 11, and the first electrodes 10 are generally arranged according to the array unit 50. The first driving line 11 can be a static driving, dynamic driving, or active driving vertical structure LED3 display driving line. For example, when the driving base plate 1 is a printed circuit board, the first driving line 11 for static or dynamic driving of the vertical structure LED3 can be set on the circuit board, which is connected to each first electrode 10, and the first electrode 10 can be a metal pad on the circuit board. When the driving base plate 1 is a glass plate or plastic film, the first driving line 11 can be an active driving circuit. The active driving circuit is a driving circuit based on thin film transistors (TFT, including α-Si, polysilicon, IGZO, etc. TFTs). The active driving circuit used for driving the vertical structure LED3 display is generally a current driving circuit (similar to the active driving of OLED), which can independently control the output current of each first electrode 10 to control the light emission of its vertical structure LED3 to form a display image. When the driving base plate 1 is a glass plate or a plastic film, the first electrode 10 can be an exposed conductor area or conductor block of metal or non-metal.

[0077] The flexible film 2 may also be provided with a portion of the display driving circuitry, namely the second driving circuitry 21, and the second electrode 20 is the output terminal of the second driving circuitry 21. For example, when the first driving circuitry 11 is a row driving circuitry for dynamically driving the vertical structure LED3, the second driving circuitry 21 may together constitute a column driving circuitry for dynamically driving the vertical structure LED3; while when the first driving circuitry 11 is an active driving circuit, the second electrode 20 may be a common electrode shared by each array unit 50, and the second driving circuitry 21 may be an auxiliary circuitry or conductive film layer used to enhance the conductivity of the common electrode.

[0078] Vertical structure LED3 can be based on semiconductors such as GaAs, GaP, SiC, and GaN, and can be manufactured using existing vertical structure LED3 manufacturing processes. For example, its light-emitting semiconductor layers (such as P-type layers, N-type layers, and quantum well layers) are generally epitaxially grown on an epitaxial substrate (such as sapphire), and finally peeled off from the epitaxial substrate using a lift-off process (such as laser lift-off). The P-electrode and N-electrode of the vertical structure LED3 chip are located on two opposite sides of the film structure. One side, which serves as the light-emitting surface, is the fourth electrode 31 (generally the N-electrode), and the other side is the third electrode 30 (generally the P-electrode).

[0079] In this embodiment, a portion of the flexible film 2 is lifted by the corresponding vertical structure LED 3. A gap region 200 with a gap is formed between the flexible film 2 and the driving base plate 1 in the vicinity of the vertical structure LED 3. The electrode overlapping region 100 and the gap region 200 overlap. The gap region 200 is the area of ​​the flexible film 2 protruding near the vertical structure LED 3. The gap near the vertical structure LED 3 is formed by the flexible film 2 extending laterally from the top of the vertical structure LED 3 according to its own resistance to bending; or, it can be considered that the gap near the vertical structure LED 3 is formed because the deformation of the flexible film 2 is limited and does not bend completely according to the edge of the vertical structure LED 3. The vertical LED structure 3 lifts the flexible film 2, causing the flexible film 2 to be stretched taut on top of each vertical LED structure 3. This is equivalent to the flexible film 2 applying a certain pressure to one side of the driving base plate 1, thereby maintaining pressure between the fourth electrode 31 and the second electrode 20, ensuring conductivity. The lateral extension of the flexible film 2 forms a gap region 200 near the vertical LED structure 3, which automatically prevents short circuits between the first electrode 10 and the second electrode 20. The electrode overlap region 100 overlaps with the gap region 200, meaning the electrode overlap region 100 is relatively wide, encompassing not only the area occupied by the vertical LED structure 3 but also extending to the adjacent area. Within the gap region 200 adjacent to the vertical LED structure 3, although the first electrode 10 and the second electrode 20 overlap, they will not short circuit each other. By making the electrode overlap region 100 wider, the vertical LED structure 3 can be positioned anywhere within the electrode overlap region 100 during manufacturing without strict alignment, which helps reduce the manufacturing difficulty of the LED array device.

[0080] In this embodiment, the flexible film 2 is bonded to the driving base plate 1 by adhesive 300; the first electrode 10 and the second electrode 20 are bonded together by adhesive 300 filled in the gap area 200. Thus, the adhesive 300 maintains tensile stress in the vertical direction to retain the deformation of the flexible film 2, so that the vertical structure LED 3 is pressed and the second and fourth electrodes maintain good conductivity.

[0081] In this embodiment, the third electrode 30 can be an exposed surface of the semiconductor layer or a thin metal plating layer, such as a thin plating layer of gold, silver, copper, zinc, iron, or their alloys with a thickness of 5 nm to 1000 nm. The overall thickness of this vertical structure LED3 is generally 1 to 20 μm. Alternatively, the third electrode 30 can also be a thicker conductive substrate bonded to the aforementioned semiconductor layer, such as a metal plate or a conductive silicon substrate, thereby allowing the overall thickness of the vertical structure LED3 to exceed 100 μm.

[0082] In this embodiment, the size of the vertical structure LED3 can be 5 to 500 μm (selected according to factors such as the array unit spacing), and its shape can be square, round, or other shapes.

[0083] In this embodiment, the flexible film 2 is a plastic film with a thickness of no more than 0.4 mm. Specifically, the flexible film 2 can be a plastic film such as PET (polyethylene terephthalate), PI (polyimide), CPI (transparent polyimide), or PC (polycarbonate) with a thickness of no more than 0.4 mm. Specifically, in order to improve flexibility to better adapt to multiple vertically structured LED protrusions 3, the thickness of the plastic film is preferably no more than 0.3 mm, especially no more than 0.2 mm. For example, a plastic film with a thickness of 0.05 to 0.2 mm can be selected. Generally, the plastic film is preferably a colorless and transparent plastic film, or it can also be a white transparent plastic film with optical diffusion properties. The flexible film 2 is a transparent glass film with a thickness of no more than 0.2 mm. Generally, a transparent glass film with a thickness of no more than 0.2 mm, especially no more than 0.1 mm, also has a certain degree of flexibility, thereby adapting to multiple vertically structured LED protrusions 3. The flexible film 2 is a glass film, which has better heat resistance, and therefore it is easier to process the flexible film 2 into a second electrode 20 with better performance and the required driving circuit through high temperature process.

[0084] In this embodiment, the first electrode 10 is a solder pad, and the third electrode 30 of the vertical structure LED3 is soldered to the first electrode 10 through a solder metal layer 13. Therefore, the connection between the vertical structure LED3 and the driving base plate 1 is more robust and has better conductivity. Displacement is less likely to occur in subsequent processing steps, ensuring high manufacturing yield.

[0085] In this embodiment, the second electrode 20 is a transparent electrode made of a silver nanowire coating, which can prevent the second electrode 20 from breaking when the flexible film 2 is pressed by the vertical structure LED 3, thus making the yield of this vertical structure LED 3 display higher.

[0086] Referring to Figure 4, the manufacturing method of the LED array device provided in this embodiment includes the following steps:

[0087] (1) Multiple first electrodes 10 are provided on the outer side of the driving base plate 1, and multiple vertical structure LEDs 3 are provided on the outer side of the driving base plate 1, and the third electrodes 30 on the inner side of each vertical structure LED 3 are respectively connected to the corresponding first electrodes 10 to form a conductive path.

[0088] (2) First, adhesive 300 is applied to the outer side of the driving base plate 1, and the flexible film 2 is aligned with the driving base plate 1 so that the second electrode 20 on the flexible film 2 and the first electrode 10 on the driving base plate 1 form an electrode overlap area 100. Then, the flexible film 2 is pressed onto the driving base plate 1 so that the flexible film 2 is bonded to the driving base plate 1 by adhesive 300, and pressure is applied so that the flexible film 2 is pressed by the vertical structure LED 3 so that the second electrode 20 and the fourth electrode 31 of the vertical structure LED 3 form a conductive connection.

[0089] (3) Allow the adhesive to cure at 300°C while maintaining pressure;

[0090] (4) Remove the pressure, and the flexible membrane 2 maintains its pressing state against the vertical structure LED 3 under the adhesion of the adhesive 300.

[0091] The driving base plate 1 can be pre-designed with overflow holes (such as through holes) or overflow channels, so that the excess adhesive 300 applied to the driving base plate 1 in steps (2) and (3) (assuming sufficient adhesive was applied in step (2)) flows away from the overflow holes or overflow channels, ensuring that the final adhesive layer thickness is sufficient to allow the flexible film 2 to effectively press against the vertical structure LED 3. For example, the average thickness of the final adhesive layer is less than the thickness of the vertical structure LED 3. Alternatively, the driving base plate 1 may not need to be pre-designed with overflow holes or overflow channels. In step (2), by controlling the amount of adhesive applied, the average thickness of the adhesive 300 on the board surface after curing is less than the thickness of the vertical structure LED 3, so as to ensure that the final flexible film 2 can effectively press against the vertical structure LED 3.

[0092] In this embodiment, in step (2), a flexible pressure plate 60 (such as a silicone or foam pressure plate) is used to press the flexible membrane 2 to achieve the pressure. When the flexible pressure plate 60 applies pressure to the flexible membrane 2, it can adapt to the protrusions of the vertical LED structures 3 at various locations, so that the flexible membrane 2 is pressed tightly onto each vertical LED structure 3.

[0093] In this embodiment, the adhesive 300 is a two-component adhesive, which is cured by natural reaction at room temperature in step (3); or, the adhesive 300 is a thermosetting adhesive, which is cured by heating in step (3); or, the adhesive 300 is a hot melt adhesive, which is first heated and melted into a liquid state in step (2) so as to press the flexible film 2 onto the driving base plate 1 so that the second electrode 20 on the flexible film 2 and the fourth electrode 31 of the vertical structure LED 3 are conductive; and it is cured by cooling in step (3).

[0094] Example 2

[0095] Referring to Figure 5, while all other parts are the same as in Embodiment 1, the difference lies in that: in this embodiment, the fourth electrode 31 of the vertical structure LED 3 is provided with a conductive protrusion 311. The conductive protrusion 311 can be a metal bump, such as a tin alloy bump, provided on the fourth electrode 31. The conductive protrusion 311 ensures good contact between the fourth electrode 31 and the second electrode 20.

[0096] Example 3

[0097] Referring to Figure 6, while all other parts are the same as in Embodiment 1, the difference lies in that: in this embodiment, the surface of the second electrode 20 is further provided with a soft conductive coating 202. Specifically, the soft conductive coating 202 can be a conductive polymer coating (such as PEDOT:PSS) or other conductive adhesive layer 32 (such as conductive acrylic) disposed on the second electrode 20. Thus, when the flexible film 2 is pressed onto the vertical structure LED 3, the second electrode 20 and the fourth electrode 31 can form better conductivity.

[0098] Example 4

[0099] Referring to Figure 7, while all other parts are the same as in Embodiment 1, the difference is that in this embodiment, the adhesive 300 is also sandwiched between the fourth electrode 31 and the second electrode 20, and the adhesive 300 contains conductive particles 301. The conductive particles 301 are sandwiched between the fourth electrode 31 and the second electrode 20 to form a conductive connection between the fourth electrode 31 and the second electrode 20.

[0100] The conductive particles 301 can be conductive metal particles or carbon particles, and their size is generally no larger than 1 / 2 of the thickness of the vertical structure LED3. Preferably, their particle size is more than an order of magnitude smaller than the thickness of the vertical structure LED3. For example, the conductive particles 301 can be nanometer-sized, an order of magnitude smaller than the thickness of the vertical structure LED3 (micrometer level). Therefore, they can be clamped by the fourth electrode 31 and the second electrode 20 to ensure their conductive connection, while they are generally not clamped in the gap region 200 to avoid short circuit between the first electrode 10 and the second electrode 20. The aforementioned conductive particles 301 can generally be pre-mixed with adhesive 300 and then applied to the drive base plate 1 along with the adhesive 300.

[0101] Example 5

[0102] Referring to Figure 8, while all other parts are the same as in Embodiment 4, the difference lies in that: in this embodiment, the driving base plate 1 is made of a flexible film. Therefore, the LED array device can not only be made into a flexible device, but when the vertical structure LED 3 is pressed, both the driving base plate 1 and the flexible film 2 deform, rather than the deformation occurring entirely on the flexible film 2. This results in a more uniform stress distribution and improves the durability of the LED array device.

[0103] Example 6

[0104] Referring to Figures 9-10, while all other parts are the same as in Embodiment 1, the difference lies in the following: In this embodiment, each electrode overlap region 100 is provided with multiple vertical structure LEDs 3, and these multiple vertical structure LEDs 3 are randomly distributed within their respective electrode overlap regions 100. Therefore, it is easier to set the vertical structure LEDs 3 onto the electrode overlap regions 100 through self-adhesion, self-assembly, or other methods, resulting in higher manufacturing efficiency. Random distribution means that the number of vertical structure LEDs 3 in different electrode overlap regions 100 (array units 50) varies (but can have statistical characteristics, such as conforming to a Gaussian distribution), and their positional distribution also differs. The random distribution of the vertical structure LEDs 3 makes it easier to set them onto the electrode overlap regions 100 through self-adhesion, self-assembly, or other methods, resulting in higher manufacturing efficiency.

[0105] In this embodiment, the flexible film 2 has a deformable structure, which includes protrusions corresponding to the plurality of vertical LED structures 3. Therefore, the flexible film 2 can easily adapt to the protrusions of the plurality of vertical LED structures 3 at different positions through its own deformation, ensuring that the fourth electrode 31 of the plurality of vertical LED structures 3 maintains good contact with the second electrode 20 of the flexible film 2.

[0106] Example 7

[0107] Referring to Figures 11-12, while all other parts are the same as in Embodiment Six, the difference lies in that: in this embodiment, the adhesive 300 further includes insulating spacer particles 302, which are sandwiched in the area outside the vertical structure LED 3 to further maintain a gap between the flexible film 2 and the driving base plate 1. This addition of insulating spacer particles 302 prevents short circuits between the first electrode 10 and the second electrode 20 due to excessive span.

[0108] The insulating spacer particles 302 are preferably microspheres or microrods made of materials such as plastic, glass, or insulating silicon, with a size preferably 0.2 to 0.8 times the thickness of the vertical structure LED 3. They are located outside the vertical structure LED 3, especially in the area embedded between the vertical structure LED 3, to further maintain the gap between the flexible film 2 and the driving base plate 1. The insulating spacer particles 302 can also be premixed with adhesive 300 and then applied to the driving base plate 1 along with the adhesive 300. They are then scraped off from the top of the vertical structure LED 3 using a certain scraping method (to avoid them being on top of the vertical structure LED 3).

[0109] Example 8

[0110] Referring to Figures 13-15, while all other parts are the same as in Embodiment 6, the difference lies in that: in this embodiment, the gap region 200 retains a negative pressure cavity 201. This allows the flexible film 2 to be pressed tightly onto the vertical LED structure 3 by atmospheric pressure.

[0111] In the manufacturing method of the LED array device provided in this embodiment, in step (2), the adhesive 300 leaves a gap in the electrode overlap area 100; under negative pressure, the flexible film 2 is pressed onto the driving base plate 1 and bonded together, and the area where the adhesive 300 is left open forms a negative pressure cavity 201, so that the flexible film 2 is pressed onto the vertical structure LED 3 by the atmosphere; in step (4), the negative pressure environment is removed, and the negative pressure cavity 201 is pressed by the atmosphere outside, so that the flexible film 2 is generated and kept in a concave state at the part of the electrode overlap area 100, which makes the second electrode 20 pressed onto the fourth electrode 31 to form conductivity.

[0112] The above steps do not require the adhesive 300 to cure under pressure, thus increasing manufacturing efficiency. Generally, adhesive 300 can be a curable adhesive, such as a two-component adhesive, hot melt adhesive, UV-curable adhesive, or thermosetting adhesive, which can be cured after step (3). Alternatively, adhesive 300 can also be a self-adhesive, which does not require curing after step (3).

[0113] Example 9

[0114] Referring to Figure 16, while all other parts are the same as in Embodiment 7, the difference lies in that: in this embodiment, the third electrode 30 of the vertical structure LED3 is bonded to the first electrode 10 through a conductive adhesive layer 32, and the third electrode 30 of the vertical structure LED3 forms a conductive connection with the first electrode 10 by atmospheric pressure. Therefore, the vertical structure LED3 can be directly bonded to the first electrode 10 by an adhesive method, avoiding the soldering process, and the first electrode 10 does not need to be designed as a solder pad, making its manufacturing more convenient.

[0115] In this embodiment, the driving base plate 1 is made of a flexible film. Therefore, the LED array device can be made flexible, and when the vertical LED 3 is pressed, both the driving base plate 1 and the flexible film 2 deform, rather than the deformation occurring entirely on the flexible film 2. This results in a more uniform stress distribution and improves the durability of the LED array device.

Claims

1. An LED array device, comprising a driving base plate and a plurality of vertically structured LEDs, wherein a first electrode is provided on the outer surface of the driving base plate; characterized in that: The LED array device further includes a flexible film, which is bonded to the outer surface of the driving base plate. The inner surface of the flexible film is provided with a light-transmitting second electrode, which is disposed opposite to the first electrode and has an electrode overlap area. Each of the vertical structure LEDs is sandwiched between the driving base plate and the flexible film and is located within the corresponding electrode overlap area. The inner surface of the vertical structure LED is provided with a third electrode, which is conductive with the first electrode. The outer surface of the vertical structure LED is provided with a fourth electrode, which is conductive with the second electrode.

2. The LED array device as described in claim 1, characterized in that: A portion of the flexible film is lifted by the corresponding vertical structure LED, and a gap region with a gap is formed between the flexible film and the driving base plate in the vicinity of the vertical structure LED.

3. The LED array device as described in claim 2, characterized in that: The electrode overlapping area and the gap area have an overlapping region.

4. The LED array device as described in claim 2, characterized in that: The first electrode and the second electrode are bonded together by adhesive filling the gap area.

5. The LED array device as described in claim 2, characterized in that: The gap area retains a negative pressure cavity.

6. The LED array device according to any one of claims 1-5, characterized in that: The flexible membrane has a deformation structure, which includes protrusions corresponding to the respective plurality of vertical structure LEDs.

7. The LED array device according to any one of claims 1-5, characterized in that: Each array unit has a vertically structured LED.

8. The LED array device according to any one of claims 1-5, characterized in that: Each array unit has multiple vertical structure LEDs, which are randomly distributed within their electrode overlap area.

9. The LED array device according to any one of claims 1-5, characterized in that: The drive base plate is made of a flexible membrane.

10. A method for manufacturing an LED display device, characterized in that... Includes the following steps: (1) Multiple first electrodes are set on the outer side of the driving base plate, and multiple vertical structure LEDs are set on the outer side of the driving base plate, and the third electrodes on the inner side of each vertical structure LED are respectively connected to the corresponding first electrodes to form a conductive path. (2) First, apply adhesive to the outer side of the driving base plate and align the flexible film with the driving base plate so that the second electrode on the flexible film and the first electrode on the driving base plate form an electrode overlap area. Then, press the flexible film onto the driving base plate so that the flexible film is bonded to the driving base plate through adhesive and apply pressure so that the flexible film is pressed by the vertical structure LED so that the second electrode on the flexible film and the fourth electrode of the vertical structure LED form a conductive connection. (3) Curing the adhesive; (4) The flexible film is held in place by the vertical structure LED under the adhesive force of the adhesive.

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