CN115775818A - Display substrate, manufacturing method and display device - Google Patents

Abstract

The invention provides a display substrate, a manufacturing method and a display device, wherein the display substrate comprises: the back plate is provided with a driving circuit; a precursor layer disposed on the backplane and comprising a conductor unit, a void, and a precursor, the conductor unit and the void disposed in the precursor; and the display chip is arranged on the precursor layer, and the electrode of the display chip is electrically connected with the corresponding bonding pad on the driving circuit through the plurality of conductor units. The invention can improve the short circuit or open circuit phenomenon of the display chip caused by the warping of the transfer substrate.

Description

Display substrate, manufacturing method, and display device

technical field

The invention relates to the field of display technology manufacturing, in particular to a display substrate, a manufacturing method, and a display device.

Background technique

Micro-LED (Micro Light Emitting Diode, Micro-LED) is a new generation of display technology. Compared with the existing liquid crystal display, Micro-LED has 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 display technology, it is necessary to transfer a large number of LED chips from the transfer substrate to the backplane provided with the driving circuit to realize the electrical connection between the electrodes of the LED chip and the driving circuit. During the process of electrical connection between the electrodes of the LED chip and the drive circuit, the transfer substrate may be warped, and then the chips in the middle of the transfer substrate may be disconnected due to pressure, and the chips on the edge of the transfer substrate may be bonded due to the warping of the transfer substrate. The phenomenon of low degree of cooperation or open circuit.

Contents of the invention

In view of the above-mentioned shortcomings of the prior art, the purpose of the present invention is to provide a display substrate, a manufacturing method, and a display device, which are used to solve the problem of warping of the transfer substrate when the electrodes of the LED chip and the driving circuit are electrically connected in the prior art. The problem.

In order to achieve the above purpose and other related purposes, the present invention provides a display substrate, comprising:

a backplane, the backplane is provided with a driving circuit;

a precursor layer, the precursor layer is disposed on the back plate, and the precursor layer includes a conductor unit, a void and a precursor, the conductor unit and the void are disposed in the precursor;

A display chip, the display chip is arranged 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 the conductor units.

Optionally, a plurality of the conductor units are gathered at the position of the precursor layer corresponding to the electrodes of the display chip, and the voids are dispersed in the precursor.

Optionally, the precursor includes one of polyimide and polyurethane.

Optionally, the conductor unit includes a graphene sheet.

A method of manufacturing a display substrate, comprising:

providing a backplane with a drive circuit disposed on its surface;

A precursor liquid is coated on the side of the backplane on which the driving circuit is arranged, and the precursor liquid includes a conductor unit and a precursor;

bonding the display chip to the precursor body fluid, and docking the electrodes of the display chip with the corresponding pads on the drive circuit on the backplane;

Under the first temperature condition, a first pressure is applied to the display chip, and the electrodes of the display chip are bonded to corresponding pads on the driving circuit.

Optionally, applying a first pressure to the display chip to bond the electrodes of the display chip to the corresponding pads on the drive circuit includes:

controlling the current temperature to reach the first temperature, so that the precursor liquid generates cavities, and the cavities generate degrees of freedom for the conductor unit;

Applying the first pressure to the display chip, so that the electrodes of the display chip restrict the degree of freedom, and a plurality of the conductor units are gathered at positions where the precursor liquid corresponds to the electrodes of the display chip;

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

Optionally, the precursor includes one of polyimide and polyurethane.

Optionally, the conductor unit includes a graphene sheet.

Optionally, the first temperature T satisfies the condition: 180°C≥T≥150°C.

A display device, comprising a backplane and a plurality of display chips, the backplane is provided with a driving circuit, and the electrodes of the plurality of display chips are connected to the corresponding pads on the driving circuit by the method for manufacturing the display substrate. Bond.

As mentioned above, the present invention provides a display substrate, a manufacturing method, and a display device. In the present invention, the warpage of the transfer substrate during the bonding process is eliminated through an elastic precursor layer, and the display caused by the warpage of the transfer substrate is avoided. Chip short circuit or open circuit occurs;

By providing a plurality of conductor units in the precursor layer, the plurality of 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;

The conductor units in different precursor layer regions can be isolated by the voids in the precursor, avoiding the electrical connection between conductor units in different precursor layer regions, and avoiding the display in different precursor layer regions The chip is shorted.

Description of drawings

FIG. 1 is a schematic structural diagram of a display substrate in an embodiment of the present invention.

FIG. 2 is a schematic flow chart showing a substrate manufacturing method in an embodiment of the present invention.

FIG. 3 is a schematic structural diagram of a backplane in an embodiment of the present invention.

FIG. 4 is a schematic diagram of coating precursor liquid in an embodiment of the present invention.

FIG. 5 is a schematic diagram showing bonding of a chip to a backplane in an embodiment of the present invention.

FIG. 6 is a schematic diagram showing the bonding of a display chip and a driving circuit in an embodiment of the present invention.

FIG. 7 is a schematic flow chart of bonding a display chip and a driving circuit in an embodiment of the present invention.

FIG. 8 is a schematic diagram of backplane warping in an embodiment of the present invention.

FIG. 9 is a schematic structural diagram of a display device in an embodiment of the present invention.

Part number description

1-backplane, 2-precursor layer, 20-precursor liquid, 21-precursor, 22-conductor unit, 23-cavitation, 3-transfer substrate, 4-display chip, 5-direction of the 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 ways

In the following description, numerous specific details are given in order to provide a more thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without one or more of these details. In other examples, some technical features known in the art are not described in order to avoid confusion with the present invention.

It should be understood that the invention can be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity. Like reference numerals refer to like elements throughout.

It will be understood that when an element or layer is referred to as being "on," "adjacent," "connected to" or "coupled to" another element or layer, it can be directly on the other element or layer. A layer may be on, adjacent to, connected to, or coupled to other elements or layers, or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" another element or layer, there are no intervening elements or layers present. layer. It will be understood that, although the terms first, second, third etc. may be used to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present invention.

During the bonding process of the LED chip/display chip and the driving circuit of the backplane, the welding material, welding process, or the size of the transfer substrate may cause the warping of the transfer substrate, which in turn will cause chip bonds on the transfer substrate. For example, due to the 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 under pressure, which in turn leads to a short circuit between the electrodes of the display chip at the center, and for example , due to the stress dispersion at the edge of the transfer substrate, the electrical connection between the display chip at the edge of the transfer substrate and the backplane is subject to stretching, which leads to the phenomenon that the display chip at the edge is just bonded or disconnected. Therefore, the present invention provides a Display substrates to improve warping of transfer substrates during bonding.

Referring to FIG. 1 , the present invention provides a display substrate, including a backplane 1 , a precursor layer 2 and a display chip 4 .

As shown in FIG. 1, a drive circuit may be provided on the backplane 1, for example, the drive circuit may include thin film transistors (Thin Film Transistor, TFT) and signal lines, and the drive circuit connects and drives each display chip 4. Make each display chip 4 realize a display function as a display pixel of a display device.

As shown in Figure 1, the precursor layer 2 is arranged on the back plate 1, the precursor layer 2 includes a conductor unit 22, a cavity 23 and a precursor 21, the conductor unit 22 and the cavity 23 is set in the precursor 21, and the precursor 21 is made of elastic material, which can effectively eliminate the warping of the transfer substrate during the bonding process, and avoid the short circuit or disconnection of the display chip caused by the warping of the transfer substrate. .

As shown in FIG. 1, 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 a plurality of conductor units 22, in order to effectively realize For the electrical connection between the electrodes of the display chip 4 and the backplane 1, a plurality of conductor units 22 are arranged in the precursor layer 2, and the plurality of conductor units 22 in the connected state can form an effective path to realize the connection between the electrodes of the display chip 4 and the backplane 1. The electrical connection between the corresponding pads on the driving circuit of the backplane 1, and the voids 23 in the precursor 21 can isolate the conductor units 22 between different precursor layer 2 regions, avoiding different precursors Conductor units 22 in the region of the layer 2 are electrically connected to avoid short circuits in 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).

As shown in Figure 1, in order to improve the power supply efficiency and stability between the display chip 4 and the driving circuit of the backplane 1, a plurality of conductor units 22 can be gathered under the electrodes of the display chip 4, and a plurality of The conductor units 22 are gathered along the direction 6 of electrical connection, and then the multiple conductor units 22 gathered can form electrical signal conduction and electrical connection along the direction 6 of electrical connection. Bubbles 23 are dispersedly arranged in the precursor 21, for example, the empty bubbles 23 can be dispersedly arranged along the extending direction of the plane of the precursor layer 2, so as to avoid the gap between the conductor units 22 in different regions on the extending direction of the plane of the precursor layer 2. electrical connection between them.

As shown in FIG. 1 , in some embodiments, the warpage of the transfer substrate is absorbed by an elastic precursor 21, and the precursor 21 includes one of polyimide and polyurethane. For example, the precursor 21 can be set as Polyimide (Polyimide, PI), a class of polymers containing imide rings (-CO-N-CO-) on the main chain of polyimide, an elastic organic polymer material that can effectively absorb and transfer The warping of the substrate, while polyimide has good insulating properties, avoids the electrical connection between the conductor units 22 in different regions in the direction of the extension of the precursor layer 2 plane, and for example, the precursor 21 can be set to polyurethane ( Polyurethane, PU), the polymer containing repeated -HNCOO-structural units in its main chain, is generally formed by addition polymerization of polyisocyanate and polyol polymer, etc., and can also change the NCO and OH in the polymer Ratio, to obtain a polyurethane with certain elasticity, thermosetting, thermoplasticity and good insulation, which can not only effectively absorb the warping of the transfer substrate, but also avoid the generation of electrical resistance between the conductor units 22 in different regions in the direction of the extension of the precursor layer 2 plane. connect.

As shown in Figure 1, in order to absorb the warpage of the transfer substrate and carry the display chip 4, it is necessary to prevent the too thin precursor layer 2 from being able to effectively absorb the warpage of the transfer substrate, and to avoid the fact that the too thick precursor layer 2 is not conducive to display. The electrodes of the chip 4 are electrically connected to the driving circuit of the backplane 1, and the thickness of the precursor layer 2 is 2×10 ⁻⁵ meters to 5×10 ⁻⁵ meters. For example, the thickness of the precursor layer 2 is selected 3×10 ^-5 meters, that is, 30 microns, and for example, the thickness of the precursor layer 2 is 4×10 ^-5 meters, that is, 40 microns, and the thickness of the precursor layer 2 can also be adjusted depending on the size or diameter of the conductor unit 22 For example, when the diameter of the selected conductor unit 22 is relatively large, correspondingly, the thickness of the precursor layer 2 can be set to 5×10 ^-5 meters, and for example, when the diameter of the selected conductor unit 22 is relatively small, correspondingly , the thickness of the precursor layer 2 can be set to 2×10 ⁻⁵ meters.

As shown in FIG. 1, the conductor unit 22 can be selected from a material with light weight and good electrical conductivity, and the shape of the conductor unit 22 can be set as one of flakes or particles. In some embodiments, The conductor unit 22 includes a graphene sheet, and graphene (Graphene) is a new material that carbon atoms connected by ^sp2 hybridization are tightly packed into a single-layer two-dimensional honeycomb lattice structure, which has excellent electrical conductivity and can Through the tunneling effect (TunnelingEffect, TE), the precursor 21 forms an aggregation along the direction 6 of electrical connection, that is, a thin insulating layer is sandwiched between two conductor units 22, which are subject to quantum or electronic forces In the case of the insulation layer, the potential barrier of the insulating layer is broken to form the migration of electrons, and then the conduction and electrical connection of the electrical connection are realized.

As shown in Figure 1, in some embodiments, the diameter of the graphene sheet is 0.5×10 ^-6 m to 2×10 ^-6 m, for example, the thickness of the precursor layer 2 is relatively thin, which can be set to 2× 10 ^-5 meters, the diameter of the graphene sheet is set to 0.5×10 ^-6 meters, that is, the thickness of the precursor layer is 20 micrometers, the thickness of the graphene sheet is 5 micrometers, along the electrically connected Gather at least 4 graphene sheets in the direction 6. The electrodes of the display chip 4 are electrically connected to the backplane 1 through the graphene sheets, so as to avoid the increase in the probability of short circuit caused by the aggregation of more graphene sheets. For example, The thickness of the precursor layer 2 is relatively thick, which can be set to 5×10 ^-5 meters, and the diameter of the graphene sheet is set to 2×10 ^-6 meters, that is, the thickness of the precursor layer is 50 microns, and the graphene The thickness of the sheet is 20 microns, and at least 3 graphene sheets are gathered in the direction 6 along the electrical connection. The electrodes of the display chip 4 are electrically connected to the backplane 1 through the graphene sheet. The relatively thick precursor Layer 2 can absorb the warping of the transfer substrate with a larger size, and at the same time absorb the stress of the transfer substrate caused by the warping, so as to achieve the purpose of dispersing the internal stress of the transfer substrate.

Referring to FIG. 2 to FIG. 6 , in some embodiments, a display substrate manufacturing method is provided, including:

S1: providing a backplane 1, the backplane 1 is provided with a drive circuit;

S2: Coating a precursor liquid 20 on the backplane 1, the precursor liquid 20 includes a conductor unit 22 and a precursor 21;

S3: bonding the display chip 4 to the precursor liquid 20, and connecting the electrodes of the display chip 4 to the corresponding pads on the driving circuit;

S4: Under the first temperature condition, apply a first pressure to the display chip 4 to bond the electrodes of the display chip 4 to corresponding pads on the driving circuit.

In step S1, it is exemplarily explained below that the driving circuit includes a thin film transistor (Thin Film Transistor, TFT), and the driving circuit connects and drives each display chip 4, for example, the type of the display chip 4 includes R (red) color /red display chip, G (green) color/green display chip and B (blue) color/blue display chip, driven by the drive circuit, control the display chip to turn on or off, increase or decrease brightness, The increase or decrease of saturation and other signals enable each display chip 4 to function as a display pixel of a display device. Please refer to FIG. 3 for a schematic structural diagram of the backplane 1 .

In step S2, the following exemplifies that in the precursor liquid 20, the conductor unit 22 and the precursor 21 are in a mixed state, the shape of the conductor unit 22 includes one of flake shape and granular shape, and the precursor liquid Please refer to FIG. 4 for a schematic diagram of the shape and structure of 20 .

In step S3, for example, the transfer substrate 3 carrying a plurality of display chips 4 can be placed on the corresponding positions of the precursor liquid 20 and the back plate 1, and then bonded and aligned, and for example, by point-to-point (pick&place ) transfer technology to bond the display chip 4 with the precursor fluid 20. When the display chip 4 is bonded, the electrodes of the display chip 4 and the drive circuit on the backplane 1 are aligned. The electrodes of the display chip 4 Docking with the driving circuit on the backplane 1, so as to facilitate subsequent bonding between the display chip 4 and the driving circuit, bonding of the display chip 4 and the precursor fluid 20, and display chip 4 and the backplane 1 See Figure 5 for a schematic diagram of the driver circuit interface.

In step S4, for example, under the first temperature condition, the precursor 21 in the precursor liquid reacts, and then produces a foaming effect, forming a cavity 23. Under the first temperature condition, the precursor liquid also undergoes a volatilization effect, and then Under the action of the foaming effect and the volatilization effect, the cavity 23 is subject to the composite action of expansion and contraction, and the conductor unit 22 in the precursor fluid generates a degree of freedom, and then the shape of the conductor unit 22 in the precursor fluid is rearranged. Applying the first pressure, wherein the direction 5 of the first pressure is towards the back plate 1, under the action of the first pressure, the electrodes of the display chip 4 generate pressure on the precursor liquid, therefore, the precursor liquid corresponding to the electrodes of the display chip 4 Under the action of stress concentration, the degree of freedom of the conductor unit 22 in the precursor fluid is limited, while the freedom of movement of the conductor unit 22 in other positions in the precursor fluid is not restricted, and then the conductor unit 22 in the display chip 4 The positions of the electrode pairs are aggregated, and the aggregated conductor units 22 generate electrical connection conduction under the action of the tunneling effect, and the aggregated conductor units 22 form a stable electrical conduction structure, wherein the aggregated conductor units 22 conduct The direction of connection is the direction 6 of electrical connection, and the bonding of the display chip 4 and the driving circuit is completed. Please refer to FIG. 6 for a schematic diagram of the bonding of the display chip 4 and the driving circuit. It is the precursor layer 2, the precursor layer 2 can absorb the warpage generated by the transfer substrate 3, avoid the warpage of the transfer substrate caused by differences in the bonding process, uneven solder thickness, or uneven stress on the transfer substrate, and also avoid the warping of the transfer substrate 3 The display chip 4 at the center is short-circuited and the display chip 4 at the edge is disconnected due to the warping. Please refer to FIG. 8 for a structural diagram of the warped transfer substrate.

As shown in Figure 7, in step S4 in some embodiments, it also includes:

S41: Control the current temperature to reach the first temperature, so that the precursor body fluid generates cavities, and the cavities generate degrees of freedom for the conductor unit;

S42: Applying the first pressure to the display chip, so that the electrodes of the display chip limit the degree of freedom, and a plurality of the conductor units are gathered at positions where the precursor liquid corresponds to the electrodes of the display chip ;

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

As shown in Figure 6, in S41, it is exemplarily explained that the precursor 21 in the precursor layer 2 has a foaming effect, and then the cavity 23 will expand, and because of the volatilization effect of the precursor liquid, the cavity 23 Shrinkage occurs. Under the action of expansion and contraction of the air bubble 23, the air bubble 23 will generate a degree of freedom for the conductor unit 22. The degree of freedom includes a degree of freedom of rotation and a degree of freedom of movement. Under the action of the degree of freedom, the conductor unit 22 rearrangement in precursor layer 2;

In S42, it is exemplarily explained that by applying a first pressure to the display chip 4, wherein the direction 5 of the first pressure is toward the back plate 1, under the action of the first pressure, the electrodes of the display chip 4 are connected to the precursor liquid. Pressure is generated. Therefore, the position of the precursor liquid corresponding to the electrode of the display chip 4 is concentrated in stress. Under the effect of stress concentration, the conductor unit 22 in the precursor liquid is limited by the degree of freedom, while the movement of the conductor unit 22 in other positions in the precursor liquid is free. The degree is not limited, and the conductor units 22 are gathered at the positions of the electrode pairs of the display chip 4, and the gathered conductor units 22 are electrically connected under the effect of the tunneling effect, and the gathered conductor units 22 form a stable electrical connection. A conductive structure, wherein the conduction direction of the assembled conductor units 22 is the direction 6 of electrical connection;

In S43, for example, the drive circuit includes a plurality of pads, and the pads are bonded to the electrodes on the display chip 4 to complete the electrical connection between the display chip and the drive circuit, and an electrical signal is applied through the drive circuit to reach the display chip for display. the goal of.

In step S4, after the electrodes of the display chip are bonded to the corresponding pads on the driving circuit, the display chip can also be peeled off the transfer substrate. For example, the transfer substrate can be irradiated with laser light to produce heating effect, and then the display chip and the transfer substrate are peeled off to form a display substrate. Please refer to FIG. 1 for the structural schematic diagram of the display substrate. Together, the bonding of the display chip 4 and the drive circuit on the backplane 1 is achieved, and the purpose of electrical connection is achieved. The voids 23 in the precursor 21 can isolate the conductor units 22 between different regions of the precursor layer 2. To avoid electrical connection between the conductor units 22 in different regions of the precursor layer 2 and avoid short circuit of the display chips in different regions of the precursor layer 2 .

As shown in Figures 5 and 6, in some embodiments, the precursor 21 includes one of polyimide and polyurethane, for example, the precursor 21 can be set to polyimide (Polyimide, PI), poly A class of polymers containing imide rings (-CO-N-CO-) on the main chain of imide, an elastic organic polymer material that can effectively absorb the warping of the transfer substrate, and polyimide has Good insulation performance. Under the action of the first temperature, the precursor liquid 20 undergoes an imide reaction to release carbon dioxide, and the carbon dioxide generates voids 23 in the precursor liquid. At the same time, at the first temperature, the precursor liquid 20 also has a solvent volatilization effect Therefore, under the combined action of expansion and contraction, the cavitation drives the conductor unit 22 in the precursor fluid 20 to generate a degree of freedom of movement, and gathers at the electrodes of the display chip 4, resulting in a gap between the display chip and the driving circuit of the backplane. The electrical connection of the precursor layer 2 dispersedly arranged in the direction of the precursor layer 2 can also prevent electrical connection between conductor units in different regions in the direction of the extension of the precursor layer 2 plane. For example, the precursor 21 can be It is set to polyurethane (polyurethane, PU), a polymer containing repeated -HNCOO-structural units in its main chain, which is generally formed by addition polymerization of polyisocyanate and polyol polymers, etc., and can also change the polymer The ratio of NCO to OH can obtain polyurethane with certain elasticity, thermosetting property, thermoplasticity and good insulation. Under the action of the first temperature, the precursor body liquid 20 undergoes a polymerization reaction to release carbon dioxide, and the carbon dioxide generates vacuoles in the precursor body liquid. At the first temperature, the volatilization effect of the solvent also occurs in the precursor liquid 20, therefore, the cavitation will drive the conductor unit 22 in the precursor liquid 20 to generate a degree of freedom of movement under the compound action of expansion and contraction, and at the electrode of the display chip 4 Agglomeration is generated to generate an electrical connection between the display chip 4 and the driving circuit of the backplane 1, and the scattered air bubbles arranged in the direction of the extension of the precursor layer 2 can also avoid the formation of different regions in the direction of the extension of the plane of the precursor layer 2. Electrical connections are generated between the conductor units, and the elastic polyurethane in the precursor layer 2 can effectively absorb the warping of the transfer substrate.

As shown in FIG. 6 , in some embodiments, the conductor unit 22 includes, for example, a graphene sheet, which can be aggregated along the direction 6 of electrical connection in the precursor 21 through the tunneling effect, that is, between two conductors A thin insulating layer is sandwiched between the units 22 . Under the condition of quantum or electronic force, the potential barrier of the insulating layer is broken to form the migration of electrons, thereby realizing the conduction of electrical connection.

As shown in Figure 6, in some embodiments, the diameter of the graphene sheet is 0.5×10 ^-6 m to 2×10 ^-6 m, for example, the thickness of the precursor layer 2 is relatively thin, which can be set to 2× 10 ^-5 meters, the diameter of the graphene sheet is set to 0.5×10 ^-6 meters, that is, the thickness of the precursor layer 2 is 20 microns, the thickness of the graphene sheet is 5 microns, and the electrical connection along the Gather at least 4 graphene sheets in the direction 6, and the electrodes of the display chip 4 are electrically connected to the backplane 1 through the graphene sheets, so as to avoid the increase in the probability of short circuit caused by the aggregation of more graphene sheets, and for example , the thickness of the precursor layer 2 is relatively thick, which can be set to 5×10 ^-5 meters, and the diameter of the graphene sheet is set to 2×10 ^-6 meters, that is, the thickness of the precursor layer is 50 microns, and the graphite The thickness of the graphene sheet is 20 microns, and at least 3 graphene sheets are gathered along the direction 6 of the electrical connection. The electrodes of the display chip 4 are electrically connected to the backplane 1 through the graphene sheet, and the relatively thick precursor The bulk layer 2 can absorb the warping of the transfer substrate with a larger size, and avoid the stress concentration of the transfer substrate caused by the warping.

In some embodiments, the first temperature T satisfies the condition: 180°C ≥ T ≥ 150°C, for example, in the application scenario of a transfer substrate with a larger size, to avoid a large warpage caused by a small deformation of the transfer substrate, A relatively thick precursor layer can be set to absorb warpage and conduct electrical connections with larger-sized conductor units. In order to drive the larger-sized conductor units to move under the action of foaming, the first temperature T can be set to 180°C, that is, 180 degrees Celsius, at this time, the degree of foaming is relatively severe, which can meet the huge transfer of large-sized transfer substrates. For the electrical connection of the drive circuit on the board, a relatively thin precursor layer and a smaller-sized conductor unit can be provided. In order to drive the smaller-sized conductor unit to move under the action of foaming, the first temperature T can be set to 150°C , that is, 150 degrees Celsius. At this time, the degree of foaming is relatively mild, and it can also meet the large transfer of small-sized transfer substrates. For example, in the application scenario of a specific-sized transfer substrate, an ideal precursor can be set. Based on the thickness of the body layer and the size of the conductor unit, an appropriate first temperature T is selected, for example, T=160°C, T=165°C, T=170°C, T=175°C.

In some embodiments, the first pressure F satisfies the condition: 5Kg≥F≥3Kg, the size of the first pressure F is related to the stress of the display chip in the precursor liquid, and when the stress is large, the larger size can be limited The degree of freedom of movement of the conductor unit can avoid the pressure of the display chip on the backplane, and the aggregation of multiple conductor units at the electrodes of the display chip can also limit the freedom of movement of smaller-sized conductor units when the stress is small. Avoid free movement of conductor units to produce scattered distribution. For example, in the application scenario of larger-sized transfer substrates, in order to limit the larger-sized conductor units, the first pressure F can be set to 5Kg to gather larger-sized conductor units. At the electrodes of the display chip, an electrical connection is formed. For example, in the application scenario of a smaller-sized transfer substrate, in order to limit the smaller-sized conductor unit, the first pressure F can be set to 3Kg, and the smaller-sized The conductor units are gathered at the electrodes of the display chip to form an electrical connection. For example, in the application scenario of a transfer substrate with a specific size, the ideal thickness of the precursor layer and the size of the conductor unit can be set, and based on this, select Suitable first pressure F, for example, F=3.5Kg, T=4Kg, T=4.5Kg.

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 liquid can be adjusted to ensure the stability of the electrical connection. The mass ratio P of the conductor unit to the precursor satisfies the condition: 5:95≥P≥1:99, for example, when the thickness of the precursor layer is thicker or the size of the conductor unit is small, the conductor unit and the precursor The mass ratio of the body is selected as P=5:95. At this time, the number of conductor units mixed in the precursor liquid is large. For example, when the thickness of the precursor is relatively thin or the size of the conductor unit is large, the conductor unit and the precursor The mass ratio of the body is selected as P=1:99. At this time, the number of conductor units mixed in the precursor liquid is small, and for example, under the condition of a specific precursor layer thickness or conductor unit size, the conductor unit and the The mass ratio of the precursor is selected as P=2:98, P=3:97, and P=4:96.

In some embodiments, the present invention provides a display device, including a backplane and a plurality of display chips, the backplane is provided with a driving circuit, and the plurality of display chips adopt the display substrate manufacturing method and the driving circuit. The corresponding pads on the circuit are bonded to control the display of the display chip through the driving circuit, so that the display chip acts as a display pixel of the display device.

As shown in FIG. 9, 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 conductor units gathered in the precursor layer 2, and the display device It includes a plurality of display units 71 arranged horizontally, vertically or in an array, and 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 performs signal control to realize signal control such as turning on or off of each display chip in the display unit 71, increasing brightness or decreasing brightness, increasing saturation or decreasing saturation, and further realizing display unit 71’s specific color, specific For the display of brightness or specific saturation, the elastic precursor layer 2 absorbs the warping of the transfer substrate during the mass transfer process, which can avoid the short circuit or disconnection of the display chip of the display unit 71, and avoid the resulting dead pixels of the display unit. Alternatively, avoid color, brightness, or saturation shifts.

In order to thoroughly understand the present invention, detailed steps and detailed structures will be provided in the following description, so as to explain the technical solution proposed by the present invention. Preferred embodiments of the present invention are described in detail below, however, the present invention may have other embodiments besides these detailed descriptions.

The above-mentioned embodiments only illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical ideas disclosed in the present invention should still be covered by the claims of the present invention.

Claims (10)

1. A display substrate, comprising:

the back plate is provided with a driving circuit;

a precursor layer disposed on the backplane and comprising a conductor unit, a void, and a precursor, the conductor unit and the void disposed in the precursor;

and the display chip is arranged on the precursor layer, and the electrode of the display chip is electrically connected with the corresponding bonding pad on the driving circuit through the plurality of conductor units.

2. The display substrate according to claim 1, wherein the plurality of conductor units are gathered at positions of the precursor layer corresponding to the electrodes of the display chip, and the voids are dispersed in the precursor.

3. The display substrate of claim 1, wherein the precursor comprises one of polyimide and polyurethane.

4. The display substrate of claim 1, wherein the conductor unit comprises a graphene sheet.

5. A method for manufacturing a display substrate includes:

providing a back plate, wherein a driving circuit is arranged on the back plate;

coating a precursor liquid on the back plate, wherein the precursor liquid comprises a conductor unit and a precursor;

attaching a display chip to the precursor liquid, and butting an electrode of the display chip with a corresponding bonding pad on the driving circuit;

and under the condition of a first temperature, applying a first pressure to the display chip, and bonding the electrode of the display chip with the corresponding bonding pad on the driving circuit.

6. The method for manufacturing a display substrate according to claim 5, wherein applying a first pressure to the display chip under a first temperature condition to bond the electrodes of the display chip to corresponding pads on the driving circuit comprises:

controlling the current temperature to reach the first temperature, so that the precursor liquid generates vacuoles, and the vacuoles generate degrees of freedom for the conductor unit;

applying the first pressure to the display chip so that the electrodes of the display chip limit the degree of freedom, and the plurality of conductor units are gathered at positions where the precursor liquid corresponds to the electrodes of the display chip;

and the electrodes of the display chip are electrically connected with the corresponding bonding pads on the driving circuit through the plurality of conductor units to complete bonding.

7. The method of manufacturing a display substrate according to claim 5, wherein the precursor comprises one of polyimide and polyurethane.

8. The display substrate manufacturing method according to claim 5, wherein the conductor unit includes a graphene sheet.

9. The method for manufacturing a display substrate according to claim 5, wherein the first temperature T satisfies a condition: t is more than or equal to 150 ℃ at the temperature of 180 ℃.

10. A display device, comprising a back plate and a plurality of display chips, wherein the back plate is provided with a driving circuit, and electrodes of the plurality of display chips are bonded with corresponding bonding pads on the driving circuit by using the display substrate manufacturing method according to any one of claims 5 to 9.

Images