Display substrate, manufacturing method and display device

Abstract

The application provides a display substrate and a manufacturing method and a display device. The display substrate comprises a back plate, a front body layer, and a display chip. The back plate is provided with a driving circuit. The front body layer is arranged on the back plate and comprises a conductor unit, a void and a front body. The conductor unit and the void are arranged in the front body. The display chip is arranged on the front body layer. Electrodes of the display chip are electrically connected to corresponding pads on the driving circuit through the conductor units. The application can improve the short circuit or open circuit phenomenon of the display chip caused by the warping of the transfer substrate.

Description

Technical Field

[0001] This invention relates to the field of display technology manufacturing, and in particular to a display substrate, a manufacturing method thereof, and a display device. Background Technology

[0002] Micro-LED (Micro Light Emitting Diode) is a next-generation display technology. Compared to existing liquid crystal displays (LCDs), Micro-LEDs offer higher photoelectric efficiency, higher brightness, higher contrast, and lower power consumption, and can also be combined with flexible panels to achieve flexible displays. In the manufacturing process of Micro-LED displays, LED chips need to be transferred in large quantities from a transfer substrate to a backplane containing driving circuitry, establishing electrical connections between the LED chip electrodes and the driving circuitry. During this electrical connection process, the transfer substrate may warp, leading to open circuits in the chips in the center of the transfer substrate due to pressure, and poor bonding or open circuits in the chips at the edges of the transfer substrate due to warping. Summary of the Invention

[0003] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a display substrate, a manufacturing method thereof, and a display device to solve the problem of substrate warping when the electrodes of the LED chip are electrically connected to the driving circuit in the prior art.

[0004] To achieve the above and other related objectives, the present invention provides a display substrate, comprising:

[0005] A backplate, wherein a drive circuit is provided on the backplate;

[0006] A precursor layer is disposed on the back plate, and the precursor layer includes conductor units, cavitation bubbles and a precursor, wherein the conductor units and the cavitation bubbles are disposed in the precursor;

[0007] The display chip is disposed on the precursor layer, and the electrodes of the display chip are electrically connected to corresponding pads on the driving circuit through a plurality of conductor units.

[0008] Optionally, a plurality of the conductor units are clustered in the precursor layer at positions corresponding to the electrodes of the display chip, and the cavitation bubbles are dispersed in the precursor.

[0009] Optionally, the precursor includes one of polyimide and polyurethane.

[0010] Optionally, the conductor unit may comprise a graphene sheet.

[0011] A method for manufacturing a display substrate, comprising:

[0012] A backplane with a drive circuitry disposed on its surface is provided;

[0013] A precursor liquid is coated on the side of the backplate where the drive circuit is located. The precursor liquid includes conductor units and a precursor.

[0014] The display chip is bonded to the precursor liquid, and the electrodes of the display chip are docked with the corresponding pads on the driving circuit on the backplane.

[0015] Under a first temperature condition, a first pressure is applied to the display chip to bond the electrodes of the display chip to the corresponding pads on the driving circuit.

[0016] Optionally, applying a first pressure to the display chip to bond the electrodes of the display chip to corresponding pads on the driving circuit includes:

[0017] The current temperature is controlled to reach the first temperature, so that the precursor fluid generates cavitation bubbles, and the cavitation bubbles give degrees of freedom to the conductor unit;

[0018] The first pressure is applied to the display chip, causing the electrodes of the display chip to restrict the degree of freedom, and the plurality of conductor units are gathered in the precursor fluid at positions corresponding to the electrodes of the display chip;

[0019] The electrodes of the display chip are electrically connected to corresponding pads on the driving circuit through multiple conductor units to complete the bonding.

[0020] Optionally, the precursor includes one of polyimide and polyurethane.

[0021] Optionally, the conductor unit may comprise a graphene sheet.

[0022] Optionally, the first temperature T satisfies the condition: 180℃ ≥ T ≥ 150℃.

[0023] A display device includes a backplane and a plurality of display chips. A driving circuit is disposed on the backplane, and the electrodes of the plurality of display chips are bonded to corresponding pads on the driving circuit using the display substrate manufacturing method described above.

[0024] As described above, the present invention provides a display substrate, a manufacturing method thereof, and a display device. In the present invention, the warping of the transfer substrate during the bonding process is eliminated by an elastic precursor layer, thereby avoiding short circuits or open circuits in the display chip caused by the warping of the transfer substrate.

[0025] By setting multiple conductor units in the precursor layer, the multiple conductor units in the connected state can form an effective path to realize the electrical connection between the electrodes of the display chip and the driving circuit of the backplane.

[0026] The cavitation within the precursor layer can isolate the conductor units between different precursor layer regions, preventing electrical connections between conductor units in different precursor layer regions and avoiding short circuits in display chips in different precursor layer regions. Attached Figure Description

[0027] Figure 1 The diagram shown is a schematic representation of the structure of the display substrate in an embodiment of the present invention.

[0028] Figure 2 The diagram shown is a flowchart illustrating the display substrate manufacturing method in an embodiment of the present invention.

[0029] Figure 3 The diagram shown is a structural schematic of the backplate in an embodiment of the present invention.

[0030] Figure 4 The diagram shown is a schematic diagram of coating the precursor fluid in an embodiment of the present invention.

[0031] Figure 5 The diagram shown is a schematic of the display chip being bonded to the backplane in an embodiment of the present invention.

[0032] Figure 6 The diagram shown is a schematic of the bonding between the display chip and the driving circuit in an embodiment of the present invention.

[0033] Figure 7 The diagram shown is a schematic representation of the bonding process between the display chip and the driving circuit in an embodiment of the present invention.

[0034] Figure 8 The diagram shown is a schematic representation of backplate warping in an embodiment of the present invention.

[0035] Figure 9 The diagram shown is a schematic representation of the display device in an embodiment of the present invention.

[0036] Part Number Explanation

[0037] 1-Backplate, 2-Precursor layer, 20-Precursor fluid, 21-Precursor, 22-Conductor unit, 23-Cavity, 3-Transfer substrate, 4-Display chip, 5-Direction of first pressure, 6-Direction of electrical connection, 7-Display device, 71-Display unit, 711-Red display chip, 712-Green display chip, 713-Blue display chip. Detailed Implementation

[0038] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid obscuring the invention.

[0039] It should be understood that the invention can be embodied in various forms and should not be construed as being limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, for clarity, the dimensions and relative dimensions of layers and regions may be exaggerated. The same reference numerals denote the same elements throughout.

[0040] 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 elements, components, areas, layers, and / or portions, these elements, components, areas, layers, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or portion from another element, component, area, layer, or portion. Therefore, without departing from the teachings of this invention, the first element, component, area, layer, or portion discussed below may be referred to as the second element, component, area, layer, or portion.

[0041] During the bonding process of LED chips / display chips to the backplane driving circuit, factors such as welding materials, welding processes, or the size of the transfer substrate may cause the transfer substrate to warp, resulting in chip bonding defects on the transfer substrate. For example, due to stress concentration at the center of the transfer substrate, the electrical connection between the display chip at the center of the transfer substrate and the backplane is subjected to pressure, leading to a short circuit between the electrodes of the display chip at the center. Alternatively, due to stress dispersion at the edges of the transfer substrate, the electrical connection between the display chip at the edge of the transfer substrate and the backplane is subjected to tension, leading to the display chip at the edge being just bonded or having an open circuit. Therefore, the present invention provides a display substrate to improve the warping problem of the transfer substrate during the bonding process.

[0042] Please see Figure 1 The present invention provides a display substrate, including a backplate 1, a precursor layer 2 and a display chip 4.

[0043] like Figure 1 As shown, a driving circuit may be provided on the back plate 1. For example, the driving circuit may include, for example, a thin film transistor (TFT) and signal lines. The driving circuit connects to and drives each display chip 4, so that each display chip 4 performs the display function as a display pixel of the display device.

[0044] like Figure 1 As shown, the precursor layer 2 is disposed on the backplate 1. The precursor layer 2 includes conductor units 22, cavitation bubbles 23 and precursor 21. The conductor units 22 and the cavitation bubbles 23 are disposed in the precursor 21. The precursor 21 is made of an elastic material, which can effectively eliminate the warping of the transfer substrate during the bonding process and avoid short circuits or open circuits in the display chip caused by the warping of the transfer substrate.

[0045] like Figure 1 As shown, the display chip 4 is disposed on the precursor layer 2, and the electrodes of the display chip 4 are electrically connected to the driving circuit through multiple conductor units 22. In order to effectively realize the electrical connection between the electrodes of the display chip 4 and the backplane 1, multiple conductor units 22 are provided in the precursor layer 2. The multiple conductor units 22 in the connected state can form an effective path to realize the electrical connection between the electrodes of the display chip 4 and the corresponding pads on the driving circuit of the backplane 1. The cavitation bubbles 23 in the precursor 21 can isolate the conductor units 22 between different regions of the precursor layer 2, avoid electrical connection between the conductor units 22 in different regions of the precursor layer 2, and avoid short circuits between the display chips in different regions of the precursor layer 2. Specifically, each display chip 4 may include at least one micro-light-emitting diode (Mini / Micro-LED).

[0046] like Figure 1 In order to improve the power-conducting efficiency and stability between the display chip 4 and the driving circuit of the backplane 1, multiple conductor units 22 can be gathered below the electrodes of the display chip 4. The multiple conductor units 22 can be gathered along the electrical connection direction 6, so that the gathered multiple conductor units 22 can form electrical signal conduction and electrical connection along the electrical connection direction 6. The cavitation bubbles 23 are dispersed in the precursor 21. For example, the cavitation bubbles 23 can be dispersed along the extension direction of the plane of the precursor layer 2 to avoid electrical connection between conductor units 22 in different regions in the extension direction of the plane of the precursor layer 2.

[0047] like Figure 1As shown, in some embodiments, the warpage of the transfer substrate is absorbed by an elastic precursor 21. The precursor 21 includes one of polyimide and polyurethane. For example, the precursor 21 can be set as polyimide (PI), a type of polymer containing an imide ring (-CO-N-CO-) on its main chain. It is an elastic organic polymer material that can effectively absorb the warpage of the transfer substrate. At the same time, polyimide has good insulating properties, preventing warpage between conductor units 22 in different regions along the extension direction of the precursor layer 2 plane. Electrical connections, for example, the precursor 21 can be set as polyurethane (PU), a polymer whose main chain contains repeating -HNCOO- structural units. It is generally formed by addition polymerization of polyisocyanates and polyol polymers. The ratio of NCO to OH in the polymer can also be changed to obtain polyurethane with certain elasticity, thermosetting, thermoplasticity and good insulation. It can not only effectively absorb the warping of the transfer substrate, but also avoid electrical connections between conductor units 22 in different regions in the extension direction of the precursor layer 2 plane.

[0048] like Figure 1 As shown, in order to absorb the warpage of the transfer substrate and support the display chip 4, and to prevent the precursor layer 2 from being too thin and unable to effectively absorb the warpage caused by the transfer substrate, and also to prevent the precursor layer 2 from being too thick and hindering the electrical connection between the electrodes of the display chip 4 and the driving circuit of the backplate 1, the thickness of the precursor layer 2 is 2×10. -5 5×10 meters -5 For example, the thickness of precursor layer 2 is selected as 3×10⁻⁶ meters. -5 Meters, or 30 micrometers; for example, the thickness of precursor layer 2 is selected as 4 × 10⁻⁶. -5 The thickness of the precursor layer 2 can be adjusted according to the size or diameter of the conductor unit 22. For example, when the diameter of the selected conductor unit 22 is large, the thickness of the precursor layer 2 can be set to 5 × 10⁻⁶. -5 For example, when the diameter of the selected conductor unit 22 is small, the thickness of the precursor layer 2 can be set to 2 × 10⁻⁶ meters. -5 rice.

[0049] like Figure 1 As shown, the conductor unit 22 can be selected from materials that are lightweight and have good electrical conductivity. The shape of the conductor unit 22 can be either sheet-like or granular. In some embodiments, the conductor unit 22 includes a graphene sheet. Graphene is a material composed of sp... 2A novel material with hybridized carbon atoms tightly packed into a single-layer two-dimensional honeycomb lattice structure exhibits excellent electrical conductivity. It can form an aggregation along the electrical connection direction 6 in the precursor 21 through the tunneling effect (TE). That is, a thin insulating layer is sandwiched between two conductor units 22. Under the influence of quantum or electronic forces, the potential barrier of the insulating layer is broken, and electron migration is formed, thereby realizing the conduction and electrical connection.

[0050] like Figure 1 As shown, in some embodiments, the graphene sheet has a diameter of 0.5 × 10⁻⁶. -6 2×10 meters -6 For example, the thickness of precursor layer 2 is relatively thin, and can be set to 2×10. -5 The diameter of the graphene sheet is set to 0.5 × 10⁻⁶ meters. -6 The precursor layer is 20 micrometers thick, and the graphene sheet is 5 micrometers thick. At least four graphene sheets are aggregated along the electrical connection direction 6. The electrodes of the display chip 4 are electrically connected to the backplate 1 through the graphene sheets, avoiding an increased probability of short circuits due to the aggregation of too many graphene sheets. For example, the precursor layer 2 has a relatively thick layer, which can be set to 5 × 10⁻⁶. -5 The diameter of the graphene sheet is set to 2 × 10⁻⁶ meters. -6 The precursor layer is 50 micrometers thick, and the graphene sheet is 20 micrometers thick. At least three graphene sheets are aggregated along the electrical connection direction 6. The electrodes of the display chip 4 are electrically connected to the backplate 1 through the graphene sheets. The relatively thick precursor layer 2 can absorb the warping of the larger transfer substrate and the stress of the transfer substrate caused by the warping, thereby achieving the purpose of stress dispersion inside the transfer substrate.

[0051] Please see Figures 2 to 6 In some embodiments, a method for manufacturing a display substrate is provided, comprising:

[0052] S1: A backplane 1 is provided, and a driving circuit is provided on the backplane 1;

[0053] S2: A precursor liquid 20 is coated on the back plate 1. The precursor liquid 20 includes a conductor unit 22 and a precursor 21.

[0054] S3: Attach the display chip 4 to the precursor liquid 20, and connect the electrodes of the display chip 4 to the corresponding pads on the driving circuit;

[0055] S4: Under the first temperature condition, a first pressure is applied to the display chip 4 to bond the electrodes of the display chip 4 to the corresponding pads on the driving circuit.

[0056] In step S1, as exemplarily described below, the driving circuit includes a thin-film transistor (TFT). The driving circuit connects to and drives each display chip 4. For example, the display chips 4 may be of various types, including R (red) color display chips, G (green) color display chips, and B (blue) color display chips. Under the drive of the driving circuit, the circuit controls the display chips to turn on or off, increase or decrease brightness, increase or decrease saturation, and other signals, so that each display chip 4 functions as a display pixel in the display device to perform the display function. Please refer to the schematic diagram of the backplate 1. Figure 3 .

[0057] In step S2, as exemplarily described below, in the precursor fluid 20, the conductor unit 22 and the precursor 21 are in a mixed state. The shape of the conductor unit 22 includes either a sheet-like or granular form. For a schematic diagram of the morphology and structure of the precursor fluid 20, please refer to [link to schematic diagram]. Figure 4 .

[0058] In step S3, for example, the transfer substrate 3 carrying multiple display chips 4 can be placed at the corresponding positions of the precursor liquid 20 and the backplate 1 for bonding and alignment. Alternatively, a pick-and-place transfer technique can be used to bond the display chips 4 to the precursor liquid 20. When the display chips 4 are bonded, the electrodes of the display chips 4 are aligned with the driving circuit on the backplate 1, and the electrodes of the display chips 4 are docked with the driving circuit on the backplate 1 to facilitate subsequent bonding of the display chips 4 to the driving circuit. Please refer to the schematic diagrams for the bonding of the display chips 4 to the precursor liquid 20 and the docking of the display chips 4 with the driving circuit on the backplate 1. Figure 5 .

[0059] In step S4, for example, under a first temperature condition, the precursor 21 in the precursor fluid reacts, thereby generating a foaming effect and producing cavitation bubbles 23. Under the first temperature condition, the precursor fluid also undergoes a volatilization effect. Under the combined effects of foaming and volatilization, the cavitation bubbles 23 are subjected to a combination of expansion and contraction, giving the conductor units 22 in the precursor fluid degrees of freedom, and thus rearranging their morphology. By applying a first pressure to the display chip 4, wherein the direction 5 of the first pressure is towards the backplate 1, the electrodes of the display chip 4 exert pressure on the precursor fluid under the action of the first pressure. Therefore, the display chip... Stress concentration occurs at the position of the precursor fluid corresponding to electrode 4. Under the action of stress concentration, the conductor unit 22 in the precursor fluid is restricted in its degree of freedom, while the degree of freedom of movement of conductor units 22 at other positions in the precursor fluid is not restricted. Consequently, the conductor units 22 aggregate at the electrode pair positions of the display chip 4. Under the action of tunneling effect, the aggregated conductor units 22 generate electrical connection and form a stable electrical conduction structure. The conduction direction of the aggregated conductor units 22 is the direction 6 of the electrical connection, thus completing the bonding between the display chip 4 and the driving circuit. For a schematic diagram of the bonding between the display chip 4 and the driving circuit, please refer to [link to schematic diagram]. Figure 6 On the other hand, under the foaming effect, the precursor liquid 20 changes into the precursor layer 2. The precursor layer 2 can absorb the warpage generated by the transfer substrate 3, avoiding warpage of the transfer substrate caused by differences in bonding processes, uneven solder thickness, or uneven stress on the transfer substrate. It also avoids short circuits in the display chip 4 at the center position and open circuits in the display chip 4 at the edge position caused by the warpage of the transfer substrate 3. Please refer to the structural schematic diagram of the warpage of the transfer substrate. Figure 8 .

[0060] like Figure 7 As shown, in some embodiments, step S4 further includes:

[0061] S41: Control the current temperature to reach the first temperature, so that the precursor fluid generates cavitation bubbles, and the cavitation bubbles give degrees of freedom to the conductor unit;

[0062] S42: Apply the first pressure to the display chip, causing the electrodes of the display chip to restrict the degree of freedom, and the plurality of conductor units to gather at the positions of the precursor fluid and the electrodes of the display chip;

[0063] S43: The electrodes of the display chip are electrically connected to the corresponding pads on the driving circuit through multiple conductor units to complete the bonding.

[0064] like Figure 6In S41, it is exemplarily explained that the precursor 21 in the precursor layer 2 undergoes a foaming effect, which causes the cavitation 23 to expand. Due to the evaporation effect of the precursor liquid, the cavitation 23 contracts. Under the expansion and contraction of the cavitation 23, the cavitation 23 generates a degree of freedom for the conductor unit 22, including rotational and translational degrees of freedom. Under the action of these degrees of freedom, the conductor unit 22 is rearranged in the precursor layer 2.

[0065] In S42, by way of example, by applying a first pressure to the display chip 4, wherein the direction 5 of the first pressure is toward the back plate 1, the electrodes of the display chip 4 exert pressure on the precursor fluid under the action of the first pressure. Therefore, the position of the precursor fluid corresponding to the electrodes of the display chip 4 is stress concentrated. Under the action of stress concentration, the conductor unit 22 in the precursor fluid is restricted in its degree of freedom, while the degree of freedom of movement of the conductor unit 22 at other positions in the precursor fluid is not restricted. As a result, the conductor unit 22 gathers at the position of the electrode pair of the display chip 4. Under the action of the tunneling effect, the gathered conductor unit 22 generates an electrical connection. The gathered conductor unit 22 forms a stable electrical conduction structure, wherein the conduction direction of the gathered conductor unit 22 is the direction 6 of the electrical connection.

[0066] In S43, for example, the driving circuit includes multiple pads, which are bonded to the electrodes on the display chip 4 to complete the electrical connection between the display chip and the driving circuit. The driving circuit applies an electrical signal to achieve the purpose of displaying the chip.

[0067] In step S4, after bonding the electrodes of the display chip to the corresponding pads on the driving circuit, the display chip can be peeled off from the transfer substrate. For example, the transfer substrate can be heated by laser irradiation, thereby peeling the display chip off from the transfer substrate to form the display substrate. A schematic diagram of the display substrate structure can be found in [reference needed]. Figure 1 The display chip 4 achieves bonding with the driving circuit on the backplate 1 through the conduction of the aggregated conductor units 22, thus achieving electrical connection. The cavitation bubbles 23 in the precursor 21 can isolate the conductor units 22 between different regions of the precursor layer 2, avoiding electrical connection between the conductor units 22 in different regions of the precursor layer 2, and preventing short circuits in the display chips in different regions of the precursor layer 2.

[0068] like Figure 5 and 6As shown, in some embodiments, the precursor 21 includes one of polyimide and polyurethane. For example, the precursor 21 can be set as polyimide (PI), a type of polymer containing an imide ring (-CO-N-CO-) on its main chain. It is an elastic organic polymer material that can effectively absorb the warpage of the transfer substrate. At the same time, polyimide has good insulating properties. Under the action of the first temperature, the precursor liquid 20 undergoes an imide reaction, releasing carbon dioxide. The carbon dioxide generates cavitation bubbles 23 in the precursor liquid. At the same time, the precursor liquid 20 also exhibits solvent evaporation at the first temperature. Therefore, the cavitation bubbles, under the combined action of expansion and contraction, drive the conductor units 22 in the precursor liquid 20 to generate degrees of freedom of movement and accumulate at the electrodes of the display chip 4, generating an electrical connection between the display chip and the driving circuit of the backplane. The cavitation bubbles dispersed in the extension direction of the precursor layer 2 can also prevent electrical connections between conductor units in different regions in the extension direction of the plane of the precursor layer 2. For example, the precursor 21 can be Polyurethane (PU) is a polymer whose main chain contains repeating -HNCOO- structural units. It is generally formed by addition polymerization of polyisocyanates and polyol polymers. The ratio of NCO to OH in the polymer can also be changed to obtain polyurethane with certain elasticity, thermosetting, thermoplasticity and good insulation. Under the action of the first temperature, the precursor liquid 20 undergoes a polymerization reaction and releases carbon dioxide. The carbon dioxide generates cavitation in the precursor liquid. At the same time, the precursor liquid 20 also exhibits solvent volatilization effect under the first temperature. Therefore, the cavitation generated, under the combined action of expansion and contraction, drives the conductor unit 22 in the precursor liquid 20 to generate degrees of freedom of movement and accumulates at the electrode of the display chip 4, generating an electrical connection between the display chip 4 and the driving circuit of the back plate 1. The cavitation dispersed in the extension direction of the precursor layer 2 can also avoid the generation of electrical connections between conductor units in different regions in the extension direction of the plane of the precursor layer 2. Moreover, the elastic polyurethane in the precursor layer 2 can effectively absorb the warping of the transfer substrate.

[0069] like Figure 6 As shown, in some embodiments, the conductor unit 22 includes, for example, a graphene sheet, which can be aggregated in the precursor 21 along the direction 6 of the electrical connection through the tunneling effect. That is, a thin insulating layer is sandwiched between two conductor units 22. Under the influence of quantum or electronic forces, the potential barrier of the insulating layer is broken, and electron migration is formed, thereby realizing the conduction of the electrical connection.

[0070] like Figure 6 As shown, in some embodiments, the graphene sheet has a diameter of 0.5 × 10⁻⁶. -6 2×10 meters -6For example, the thickness of precursor layer 2 is relatively thin, and can be set to 2×10. -5 The diameter of the graphene sheet is set to 0.5 × 10⁻⁶ meters. -6 The precursor layer 2 has a thickness of 20 micrometers, and the graphene sheets have a thickness of 5 micrometers. At least four graphene sheets are aggregated along the electrical connection direction 6. The electrodes of the display chip 4 are electrically connected to the backplate 1 through the graphene sheets, avoiding an increased probability of short circuits due to the aggregation of too many graphene sheets. For example, if the precursor layer 2 is relatively thick, it can be set to 5 × 10⁻⁶. -5 The diameter of the graphene sheet is set to 2 × 10⁻⁶ meters. -6 The precursor layer is 50 micrometers thick, and the graphene sheet is 20 micrometers thick. At least three graphene sheets are aggregated along the electrical connection direction 6. The electrodes of the display chip 4 are electrically connected to the backplate 1 through the graphene sheets. The relatively thick precursor layer 2 can absorb the warping of the larger transfer substrate and avoid stress concentration of the transfer substrate caused by warping.

[0071] In some embodiments, the first temperature T satisfies the condition: 180℃ ≥ T ≥ 150℃. For example, in applications involving larger transfer substrates, to prevent small deformations of the transfer substrate from causing large warping, a thicker precursor layer can be used to absorb warping, and larger conductor units can be used to achieve electrical connections. To allow the larger conductor units to move under the foaming effect, the first temperature T can be set to 180℃, i.e., 180 degrees Celsius. At this temperature, the degree of foaming is relatively intense, which can meet the requirements of mass transfer on larger transfer substrates. For example, in applications involving smaller transfer substrates, this ensures the display on the transfer substrate... The electrical connection between the chip and the driving circuit on the backplane can be achieved by setting a relatively thin precursor layer and a small conductor unit. In order to move the small conductor unit under the foaming effect, the first temperature T can be set to 150°C. At this temperature, the degree of foaming is relatively mild and can also meet the requirements of mass transfer of small-sized transfer substrates. For example, in the application scenario of transfer substrate of a specific size, the ideal precursor layer thickness and conductor unit size can be set, and a suitable first temperature T can be selected based on this, such as T = 160°C, T = 165°C, T = 170°C, T = 175°C.

[0072] In some embodiments, the first pressure F satisfies the condition: 5Kg ≥ F ≥ 3Kg. The magnitude of the first pressure F is related to the stress of the display chip in the precursor fluid. When the stress is high, it can restrict the movement freedom of larger conductor units, preventing the display chip from pressing on the backplane and causing multiple conductor units to aggregate at the electrodes of the display chip. When the stress is low, it can also restrict the movement freedom of smaller conductor units, preventing the conductor units from moving freely and dispersing. For example, in applications with larger transfer substrates, in order to restrict the larger conductor units, the first pressure F can be... The pressure F is set to 5Kg to gather larger conductor units at the electrodes of the display chip to form an electrical connection. For example, in the application scenario of a smaller transfer substrate, in order to limit the smaller conductor units, the first pressure F can be set to 3Kg to gather the smaller conductor units at the electrodes of the display chip to form an electrical connection. For another example, in the application scenario of a transfer substrate of a specific size, the ideal precursor layer thickness and conductor unit size can be set, and an appropriate first pressure F can be selected based on this, such as F=3.5Kg, T=4Kg, or T=4.5Kg.

[0073] The thickness of the precursor layer and the size of the conductor units affect the number of conductor units required for the electrical connection between the display chip and the backplane. The number of conductor units in the precursor solution can be adjusted to ensure the stability of the electrical connection. The mass ratio P of the conductor units to the precursor satisfies the condition: 5:95 ≥ P ≥ 1:99. For example, when the precursor layer is thicker or the conductor units are smaller, the mass ratio of the conductor units to the precursor is selected as P = 5:95. In this case, the number of conductor units mixed in the precursor solution is larger. For example, when the precursor layer is thinner or the conductor units are larger, the mass ratio of the conductor units to the precursor is selected as P = 1:99. In this case, the number of conductor units mixed in the precursor solution is smaller. For example, under specific precursor layer thickness or conductor unit size conditions, the mass ratio of the conductor units to the precursor is selected as P = 2:98, P = 3:97, or P = 4:96.

[0074] In some embodiments, the present invention provides a display device, including a backplane and a plurality of display chips. A driving circuit is disposed on the backplane, and the plurality of display chips are bonded to corresponding pads on the driving circuit using the display substrate manufacturing method described above. The driving circuit controls the display of the display chips, so that the display chips serve as display pixels of the display device.

[0075] like Figure 9As shown, in some embodiments, the display chip is bonded to the backplane, and the electrodes of the display chip are electrically connected to the driving circuit on the backplane through the aggregated conductor units in the precursor layer 2. The display device includes multiple display units 71 arranged horizontally, vertically, or in an array. Each display unit 71 includes at least one red display chip 711, at least one green display chip 712, and at least one blue display chip 713. The driving circuit on the backplane controls the signals to turn on or off, increase or decrease the brightness, increase or decrease the saturation of each display chip in the display unit 71, thereby enabling the display unit 71 to display a specific color, specific brightness, or specific saturation. The elastic precursor layer 2 absorbs the warping of the transfer substrate during the mass transfer process, which can prevent short circuits or open circuits of the display chips in the display unit 71, avoid bad pixels caused by the display unit, or avoid color, brightness, or saturation deviations.

[0076] To fully understand this invention, detailed steps and structures will be presented in the following description to illustrate the technical solution proposed by this invention. Preferred embodiments of the invention are described in detail below; however, in addition to these detailed descriptions, the invention may have other embodiments.

[0077] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A display substrate, characterized in that, include: A backplate, wherein a drive circuit is provided on the backplate; A precursor layer is disposed on the backplane, and the precursor layer includes conductor units, cavitation bubbles and a precursor. The conductor units and the cavitation bubbles are disposed in the precursor. The precursor is made of an elastic material. The conductor units are clustered along the electrical connection direction at positions in the precursor layer corresponding to the display chip electrodes. The cavitation bubbles are dispersed in the precursor along the extension direction of the precursor layer plane, and the cavitation bubbles isolate the conductor units between different precursor regions to prevent short circuits. The display chip is disposed on the precursor layer, and the electrodes of the display chip are electrically connected to corresponding pads on the driving circuit through a plurality of conductor units.

2. The display substrate according to claim 1, characterized in that, The precursor includes one of polyimide and polyurethane.

3. The display substrate according to claim 1, characterized in that, The conductor unit includes a graphene sheet.

4. A method for manufacturing a display substrate, characterized in that, include: A backplane is provided, on which a drive circuit is disposed; A precursor liquid is coated on the back plate. The precursor liquid includes conductor units and a precursor, which is made of an elastic material. The display chip is bonded to the precursor liquid, and the electrodes of the display chip are docked with the corresponding pads on the driving circuit. Under a first temperature condition, a first pressure is applied to the display chip to bond the electrodes of the display chip to the corresponding pads on the driving circuit; wherein, the current temperature is controlled to reach the first temperature, so that the precursor fluid generates cavitation bubbles, and the cavitation bubbles give degrees of freedom to the conductor unit; The first pressure is applied to the display chip, causing the electrodes of the display chip to restrict the degree of freedom. Multiple conductor units are gathered at positions in the precursor fluid corresponding to the electrodes of the display chip. The electrodes of the display chip are electrically connected to corresponding pads on the driving circuit through the multiple conductor units to complete the bonding.

5. The method for manufacturing a display substrate according to claim 4, characterized in that, The precursor includes one of polyimide and polyurethane.

6. The method for manufacturing a display substrate according to claim 4, characterized in that, The conductor unit includes a graphene sheet.

7. The method for manufacturing a display substrate according to claim 4, characterized in that, The first temperature T satisfies the condition: 180℃≥T≥150℃.

8. A display device, characterized in that, The device includes a backplane and multiple display chips. A driving circuit is disposed on the backplane, and the electrodes of the multiple display chips are bonded to corresponding pads on the driving circuit using the display substrate manufacturing method as described in any one of claims 4 to 7.

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