A driving backplane, a display panel and a display panel preparation method

Abstract

This invention relates to a driving backplane, a display panel, and a method for manufacturing the display panel. During the LED chip bonding process, the deformation of the deformable circuit layer and the elastic layer can buffer the pressure between the chip electrode and the backplane electrode that are in contact first, thus avoiding damage and breakage of the LED chip due to excessive pressure. At the same time, the deformation magnitude at each position of the deformable circuit layer and the elastic layer is positively correlated with the pressure magnitude at the corresponding position. Therefore, the backplane electrode with less pressure will "bulge outward" relative to the backplane electrode with more pressure, which facilitates more complete contact between these backplane electrodes and the corresponding chip electrodes to achieve bonding, improves the bonding effect, and increases the transfer yield of the LED chip.

Description

Technical Field

[0001] This invention relates to the field of display technology, and in particular to a driving backplate, a display panel, and a method for manufacturing the display panel. Background Technology

[0002] In the fabrication of display panels, a massive number of LED chips need to be bonded to a driver backplane, especially in Micro-LED-based display panels, where bonding between the driver backplane and tens of millions of Micro-LED chips is required. To improve transfer efficiency, mass transfer has been proposed, which allows for the transfer of a large number of LED chips to the driver backplane at once, thus increasing transfer efficiency. However, in practical applications, unavoidable warpage exists between the transfer substrate and the driver backplane, and different LED chips may have height differences due to their type and manufacturing process. These factors can lead to chip interference during the transfer of LED chips to the driver backplane, affecting the yield of LED chip transfer.

[0003] Therefore, how to solve the problem of low LED chip transfer yield caused by substrate warping and the height difference of the LED chip itself is a key issue. Summary of the Invention

[0004] In view of the shortcomings of the above-mentioned related technologies, the purpose of this application is to provide a driving backplane, a display panel and a method for manufacturing the display panel, which aims to solve the problem of low LED chip transfer yield caused by substrate warping and height differences of the LED chips themselves.

[0005] This application provides a drive backplane, including:

[0006] Rigid substrate;

[0007] A deformable circuit layer covering one side of a rigid substrate; and

[0008] An elastic layer located between a rigid substrate and a deformable circuit layer;

[0009] The deformable circuit layer includes a driving circuit and multiple backplate electrodes electrically connected to the driving circuit. The backplate electrodes are disposed on the side of the deformable circuit layer that faces away from the rigid substrate.

[0010] In the aforementioned driving backplane, because an elastic layer is provided beneath the deformable circuit layer containing the backplane electrodes, even if there are height differences between different LED chips or substrate warping, resulting in different distances between the chip electrodes of different LED chips being transferred together and their corresponding backplane electrodes, this difference in distance can be compensated for by the deformation generated by the elastic layer under stress. This avoids the problem of some LED chips being damaged due to uneven bonding pressure, maintaining the reliability of the LED chips themselves. It also ensures that the difference in distance between the chip electrodes and their corresponding backplane electrodes does not affect the reliability of LED chip bonding, improving the yield of LED chip transfer bonding. On the other hand, because a rigid substrate is also provided beneath the elastic layer, it not only provides stable support for the elastic layer but also enhances the bonding effect between the chip electrodes and the backplane electrodes by utilizing the force on the rigid substrate, improving the quality of the display panel and reducing the production cost of the display panel.

[0011] Optionally, the elastic layer includes a plurality of independent elastic pads; the elastic pads are fixed on a rigid substrate, and the backplate electrodes are located on the surface of the elastic pads facing the deformable circuit layer.

[0012] In the aforementioned driving backplane, the elastic layer includes multiple independent elastic pads. This ensures that the deformation of one elastic pad will not affect the shape of other areas of the elastic layer, which helps to ensure that different areas of the elastic layer deform according to bonding requirements, further improving the transfer yield of LED chips.

[0013] Optionally, a rigid substrate is provided with multiple positioning grooves facing the same direction, the openings of the positioning grooves facing the deformable circuit, and the elastic pad is fixed in the positioning groove.

[0014] In the aforementioned drive backplate, the elastic pad is set in the positioning groove of the rigid substrate. The positioning groove limits the elastic pad, thereby improving the fixing effect of the elastic pad on the rigid substrate.

[0015] Based on the same inventive concept, this application also provides a display panel, characterized in that it includes:

[0016] Multiple LED chips; and

[0017] The drive backplate of any of the aforementioned items;

[0018] The chip electrodes of the LED chip are electrically connected to the backplate electrodes in the driver backplate.

[0019] In the aforementioned display panel, because an elastic layer is set beneath the deformable circuit layer containing the backplate electrodes in the driving backplane, even if there are height differences between different LED chips or substrate warping, resulting in different distances between the chip electrodes of different LED chips being transferred together and their corresponding backplate electrodes, this difference in distance can be compensated by the deformation generated by the force on the elastic layer. This avoids the problem of some LED chips being damaged due to uneven bonding pressure, thus maintaining the reliability of the LED chips themselves. At the same time, it ensures that the difference in distance between the chip electrodes and their corresponding backplate electrodes does not affect the reliability of LED chip bonding, improving the yield of LED chip transfer bonding. On the other hand, because a rigid substrate is also set under the elastic layer, it not only provides stable support for the elastic layer, but also enhances the bonding effect between the chip electrodes and the backplate electrodes by utilizing the force on the rigid substrate, thereby improving the quality of the display panel and reducing the production cost of the display panel.

[0020] This application also provides a method for manufacturing a drive backplate, including:

[0021] Provide a rigid substrate;

[0022] An elastic layer is fixedly disposed on one side of a rigid substrate; and

[0023] A deformable circuit layer is provided on the side of the elastic layer facing away from the rigid substrate. The deformable circuit layer includes a driving circuit and multiple backplate electrodes electrically connected to the driving circuit. The backplate electrodes are provided on the side of the deformable circuit layer facing away from the rigid substrate.

[0024] In the aforementioned method for fabricating the driving backplane, because an elastic layer is provided beneath the deformable circuit layer containing the backplane electrodes, even if there are height differences between different LED chips or warping of the substrate, resulting in different distances between the chip electrodes of different LED chips being transferred together and their corresponding backplane electrodes, this difference in distance can be compensated for by the deformation generated by the elastic layer under stress. This avoids the problem of some LED chips being damaged due to uneven bonding pressure, maintaining the reliability of the LED chips themselves. Simultaneously, it ensures that the difference in distance between the chip electrodes and their corresponding backplane electrodes does not affect the reliability of LED chip bonding, thus improving the yield of LED chip transfer bonding. On the other hand, because a rigid substrate is also provided beneath the elastic layer, it not only provides stable support for the elastic layer but also enhances the bonding effect between the chip electrodes and the backplane electrodes by utilizing the force applied to the rigid substrate, thereby improving the quality of the display panel and reducing the production cost of the display panel.

[0025] Optionally, fixing an elastic layer on one side of the rigid substrate includes:

[0026] Multiple independent elastic pads are fixedly installed on one side of a rigid substrate to form an elastic layer.

[0027] In the above-mentioned method for preparing the driving backplane, the elastic layer includes multiple independent elastic pads. This ensures that the deformation of one elastic pad will not affect the shape of other areas of the elastic layer, which is beneficial to ensure that different areas of the elastic layer deform according to the bonding requirements, and further improves the transfer yield of the LED chip.

[0028] This application also provides a method for manufacturing a display panel, including:

[0029] A driving backplane and a donor substrate with multiple LED chips are provided. The driving backplane includes a rigid substrate, an elastic layer, and a deformable circuit layer. The elastic layer is disposed between the rigid substrate and the deformable circuit. The deformable circuit includes a driving circuit and multiple backplane electrodes electrically connected to the driving circuit. The backplane electrodes are disposed on the side of the deformable circuit layer facing away from the rigid substrate.

[0030] Align the donor substrate with the driver backplane, and make the chip electrodes of the LED chip face and be opposite to the backplane electrodes;

[0031] Applying pressure toward each other to at least one of the donor substrate and the driving backplane until the chip electrode and the backplane electrode are bonded; and

[0032] Remove the donor substrate.

[0033] In the aforementioned display panel manufacturing method, because an elastic layer is provided beneath a deformable circuit layer containing backplate electrodes in the driving backplate, even if there are height differences between different LED chips or substrate warping, resulting in different distances between the chip electrodes of different LED chips being transferred together and their corresponding backplate electrodes, this difference in distance can be compensated by the deformation generated by the elastic layer under stress. This avoids the problem of some LED chips being damaged due to uneven bonding pressure, maintaining the reliability of the LED chips themselves. Simultaneously, it ensures that the difference in distance between the chip electrodes and their corresponding backplate electrodes does not affect the reliability of LED chip bonding, thus improving the yield of LED chip transfer bonding. On the other hand, because a rigid substrate is also provided beneath the elastic layer, it not only provides stable support for the elastic layer but also enhances the bonding effect between the chip electrodes and the backplate electrodes by utilizing the force applied to the rigid substrate, thereby improving the quality of the display panel and reducing its production cost.

[0034] Optionally, the multiple LED chips may include at least three different types of LED chips.

[0035] In the above-mentioned display panel manufacturing method, three different types of LED chips are simultaneously disposed on the donor substrate, which can realize the simultaneous transfer of different types of LED chips, i.e., full-color transfer, thereby improving the manufacturing efficiency of the display panel. Attached Figure Description

[0036] Figure 1a This is a schematic diagram of transfer bonding of an LED chip with a height difference, as shown in this invention.

[0037] Figure 1b This is a schematic diagram of LED chip transfer bonding under the condition of transfer substrate warping, as shown in this invention;

[0038] Figure 1c This is a schematic diagram of LED chip transfer bonding under the condition of drive backplane substrate warping, as shown in this invention.

[0039] Figure 2 This is a schematic diagram of the structure of the first drive backplate provided in an optional embodiment of the present invention;

[0040] Figure 3 This is a schematic diagram of the structure of a second drive backplate provided in an optional embodiment of the present invention;

[0041] Figure 4 This is a schematic diagram of the structure of a third driving backplate provided in an optional embodiment of the present invention;

[0042] Figure 5 This is a schematic diagram of the structure of a fourth drive backplate provided in an optional embodiment of the present invention;

[0043] Figure 6 This is a schematic diagram of the structure of the fifth drive backplate provided in an optional embodiment of the present invention;

[0044] Figure 7 This is a schematic diagram of the structure of a sixth driving backplate provided in an optional embodiment of the present invention;

[0045] Figure 8a This is a schematic diagram of a display panel provided in an optional embodiment of the present invention;

[0046] Figure 8b This is a schematic flowchart of a display panel manufacturing method provided in an optional embodiment of the present invention;

[0047] Figure 8c This is a schematic diagram illustrating a process state change of a display panel provided in an optional embodiment of the present invention;

[0048] Figure 9 This is a schematic diagram of a process state change of the drive backplane provided in another optional embodiment of the present invention;

[0049] Figure 10 This is a schematic flowchart of a method for preparing a drive backplate provided in another optional embodiment of the present invention;

[0050] Figure 11 This is a schematic flowchart of a method for preparing a drive backplane provided in another optional embodiment of the present invention;

[0051] Figure 12 This is a schematic diagram of a process state change of the drive backplane provided in another optional embodiment of the present invention.

[0052] Explanation of reference numerals in the attached figures:

[0053] 1000 - LED chip; 1001 - Transfer substrate; 1002 - Driver backplane; 1003 - Chip electrode; 1004 - Backplane electrode; 20 - Driver backplane; 21 - Rigid substrate; 22 - Elastic layer; 220 - Elastic pad; 221 - Elastic sublayer; 23 - Deformable circuit layer; 230 - Backplane electrode; 30 - Driver backplane; 40 - Driver backplane; 50 - Driver backplane; 60 - Driver backplane; 70 - Driver backplane; 80 - Display panel; 81 - LED chip; 82 - Driver backplane; 83 - Donor substrate; 91 - Rigid substrate; 920 - Elastic pad; 93 - Deformable circuit layer; 930 - Backplane electrode; 121 - Quartz substrate; 1210 - Positioning groove; 1220 - Elastic pad; 123 - FPC; 1230 - Backplane electrode. Detailed Implementation

[0054] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0055] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0056] It should be understood that when the transfer substrate 1001 simultaneously transfers two different LED chips 1000 (e.g., at least two of red, green, and blue LED chips) to the driving backplane 1002, the chip electrodes 1003 of each LED chip 1000 on the transfer substrate 1001 will not be on the same plane because the heights of the different types of LED chips 1000 are different. For example, please refer to [link to relevant documentation]. Figure 1aAs shown, in this case, if the transfer substrate 1001 is aligned with the driving backplate 1002 and held at a certain distance above the driving backplate 1002, then even without considering the warpage of the transfer substrate 1001 and the driving backplate 1002, the distance between the chip electrode 1003 of each LED chip 1000 on the transfer substrate 1001 and the corresponding backplate electrode 1004 on the driving backplate 1002 (for ease of explanation, this distance is referred to as the "bonding distance") will be different. This inevitably leads to a situation where some chip electrodes 1003 on the transfer substrate 1001 contact their corresponding backplate electrodes 1004 before other chip electrodes 1003 contact their corresponding backplate electrodes 1004. Once some chip electrodes 1003 contact their corresponding backplate electrodes 1004, it will be difficult for other chip electrodes 1003 to contact their corresponding backplate electrodes 1004, which will naturally affect the bonding effect of the LED chips 1000 that contact later. Furthermore, under normal circumstances, in order to ensure that the chip electrode 1003 that is contacted later can also bond with the corresponding backplane electrode 1004, the pressure applied to the transfer substrate 1001 is increased. This causes the LED chip 1000 that is contacted earlier to be subjected to enormous pressure. Excessive pressure can damage or even break these LED chips 1000, affecting the transfer yield of the LED chips 1000 and increasing the production cost of the display panel. For the cases of warping of the transfer substrate 1001 and the drive backplane 1002, please refer to [the relevant documentation]. Figure 1b and Figure 1c It is understandable that warping of the transfer substrate 1001 and the driving backplate 1002 can also cause differences in the bonding distance between the chip electrode 1003 and the corresponding backplate electrode 1004, which in turn causes chip interference, affects the bonding effect, and damages the reliability of the LED chip 1000.

[0057] Therefore, this application aims to provide a solution that can solve the above-mentioned technical problems, the details of which will be described in subsequent embodiments.

[0058] An optional embodiment of this application:

[0059] Firstly, this embodiment provides a driving backplane; please refer to [link / reference needed]. Figure 2 The schematic diagram of the drive backplate shown is as follows:

[0060] The drive backplane 20 includes a rigid substrate 21, an elastic layer 22, and a deformable circuit layer 23, wherein the elastic layer 22 is sandwiched between the rigid substrate 21 and the deformable circuit layer 23 in a "sandwich" manner.

[0061] The rigid substrate 21 is formed of a substrate that does not deform under external force. For example, it may include at least one of silicon substrate, quartz substrate, sapphire substrate, glass substrate, metal substrate, and plastic substrate. In some examples of this embodiment, the rigid substrate 21 may be a composite layer structure, which includes two or more layer structures. The material of each layer structure may be any one of silicon, quartz, sapphire, glass, metal, plastic, etc.

[0062] The elastic layer 22 can deform under the action of external force. In this embodiment, the elastic layer 22 mainly undergoes compressive deformation under pressure and returns to its original shape after the pressure is removed. According to Hooke's Law F = k·x, when the magnitude of the external force F is constant, the smaller the elastic modulus k of the elastic material, the larger the deformation x. In other words, the smaller the elastic modulus k of the elastic material, the easier it is for the elastic material to deform. In this embodiment, an elastic material with a small elastic modulus is usually selected to form the elastic layer 22. For example, the elastic modulus of the elastic layer 22 can be between 1 and 800 MPa. In some examples of this embodiment, the elastic modulus of the elastic layer 22 can be 35 MPa, 450 MPa, 543 MPa, or 800 MPa. Optionally, the elastic layer 22 may include at least one of photoresist, natural rubber, and PDMS (polydimethylsiloxane).

[0063] Deformable circuit layer 23 includes drive circuitry ( Figure 2 (Not shown) and backplate electrode 230. Backplate electrode 230 is electrically connected to the driving circuit on one hand, and on the other hand, it is also used for bonding to the chip electrode of the LED chip, thereby realizing the electrical connection between the LED chip and the driving circuit. Deformable circuit layer 23 covers the side of elastic layer 22 away from rigid substrate 21. It can deform with the deformation of elastic layer 22, which can avoid the problem of circuit layer cracking and circuit breakage during LED chip bonding caused by using brittle circuit layer. In this embodiment, deformable circuit layer 23 may include at least one of FPC (Flexible Printed Circuit) and liquid metal circuit board. Taking FPC as an example, deformable circuit layer 23 includes polymer substrate, such as polyimide or polyester film, in which bendable driving circuit is disposed.

[0064] In this embodiment, the drive circuitry required for the display panel can be largely disposed on the rigid substrate 21 by setting the deformable circuit layer 23. In some examples, the rigid substrate 21 may not even need to contain any wiring. However, in other examples, some of the wiring of the drive circuitry can be disposed on the rigid substrate 21 (including the surface of the rigid substrate 21 and the interior of the rigid substrate 21). The wiring in the deformable circuit layer 23 can be electrically connected to the wiring on the rigid substrate 21 through wires, vias, etc.

[0065] In some examples of this embodiment, the elastic layer 22 can be a complete layer structure, that is, the elastic layer 22 is integrally formed, such as... Figure 2 As shown. However, in some other examples of this embodiment, the elastic layer 22 may also be composed of two or more parts. For example, in one example of this embodiment, the elastic layer 22 includes two elastic sub-layers 221 located on the same plane. Please refer to [link to relevant documentation]. Figure 3 The drive backplate 30 shown has two independent elastic sublayers 221 that do not significantly affect each other; that is, when one elastic sublayer 221 is compressed, it will not cause the other to deform. In some other examples, the elastic layer 22 includes multiple sections, for example, in... Figure 4 In the schematic diagram of the drive backplane 40 shown, the elastic layer 22 includes multiple elastic pads 220, each of which is independent of the others. When the elastic layer 22 includes multiple elastic pads 220, it is necessary to ensure that the backplane electrode 230 in the deformable circuit layer 23 faces the side of the elastic pad 220 away from the rigid substrate 21; that is, the backplane electrode 230 is located on the side of the elastic pad 220 away from the rigid substrate 21. Please refer to [link to previous section]. Figure 4 As shown. It is worth noting that, although in Figure 4 The free end of the backplate electrode 230 protrudes outward from the upper surface of the deformable circuit layer 23. However, in some other examples of this embodiment, the free end of the backplate electrode 230 may also be flush with the upper surface of the deformable circuit layer 23.

[0066] In some examples of this embodiment, only one backplate electrode 230 may be provided on an elastic pad 220, that is, the backplate electrode 230 corresponds one-to-one with the elastic pad 220, such as... Figure 4As shown. Because the number of chip electrodes is usually the same as the number of backplane electrodes 230, and an LED chip includes two chip electrodes (except for array-type LED chips), there will also be two elastic pads 220 on the driving backplane 40 corresponding to one LED chip. These two elastic pads 220 are adjacent, and the distance between them is equal to the distance between the two chip electrodes in the LED chip. Therefore, in this case, one LED chip is disposed on two adjacent elastic pads 220. It is understandable that because each chip electrode is uniquely bound to the elastic pad 220 in this case, if a portion of the driving circuit is provided in the rigid substrate 21, then when the elastic pad 220 is conductive, the electrical connection between the lines in the deformable circuit layer 23 and the lines in the rigid substrate 21 can be directly achieved through the elastic pad 220.

[0067] In other examples of this embodiment, two backplate electrodes 230 may be disposed on a single elastic pad 220; see [link to relevant documentation]. Figure 5 The driving backplate 50 shown has two backplate electrodes 230 corresponding to the two chip electrodes of the same LED chip. The distance between the two backplate electrodes 230 is equal to the distance between the two chip electrodes of the LED chip. Therefore, in the driving backplate 50, an LED chip can be disposed on an elastic pad 220. In the driving backplate 50, two backplate electrodes 230 with opposite polarities are disposed on an elastic pad 220. However, in some examples, the polarities of the backplate electrodes 230 disposed on the same elastic pad 220 can also be the same. For example, in one example, two backplate electrodes are disposed on an elastic pad, but these two backplate electrodes correspond to the positive electrodes of the LED chips. In this case, the positive electrodes of two LED chips are disposed on the elastic pad. Of course, in other examples, a larger number of backplate electrodes 230 can be disposed on an elastic pad 220. The polarities of these backplate electrodes 230 can all be the same or different.

[0068] The elastic pad 220 can be fixedly disposed on the rigid substrate 21. For example, in some examples of this embodiment, it can be disposed on the rigid substrate 21 by means of adhesive bonding or snap-fit. In some examples of this embodiment, an adhesive layer can be directly disposed between the interface between the elastic pad 220 and the rigid substrate 21, and the elastic pad 220 and the rigid substrate 21 can be fixed together by the adhesive layer. Of course, considering that the deformable circuit layer 23 covering the elastic pad 220 also needs to be relatively fixed to the elastic pad 220, in some examples of this embodiment, an adhesive layer can also be disposed on the side of the elastic pad 220 away from the rigid substrate 21, and the deformable circuit 23 can be bonded together by the adhesive layer.

[0069] In other examples of this embodiment, the elastic pad 220 can be fixed on the rigid substrate 21 by means of a snap-fit ​​mechanism. For example, see [link to example]. Figure 6 The drive backplate 60 shown has multiple positioning grooves 210 corresponding to the elastic pads 220 on a rigid substrate 21. The openings of the positioning grooves 210 all face the deformable circuit layer 23. The elastic pads 220 are disposed in the positioning grooves 210, and the side of the elastic pads 220 facing the deformable circuit layer 230 is exposed in the positioning grooves 210. Undoubtedly, the size of the opening of the positioning groove 210 should be larger than the cross-sectional size of the elastic pad 220. In some examples of this embodiment, the cross-sectional size of the positioning groove 210 is consistent at all positions, that is, the positioning groove 210 is uniform in thickness from the opening to the bottom. In this case, the elastic pads 220 can be fixedly disposed on the bottom of the groove, and the depth of the positioning groove 210 is less than the height of the elastic pads 220. Of course, if the cross-section of the positioning groove 210 gradually decreases from the groove opening to the groove bottom, for example, if the longitudinal section of the positioning groove 220 is an inverted trapezoid, then the elastic pad 220 may not be able to be directly fixed to the groove bottom, but may be stuck in the middle area of ​​the positioning groove 210. In some other examples, the elastic pad 220 can be fixed to the groove wall of the positioning groove 220 by an adhesive layer while being stuck in the positioning groove 210.

[0070] In this embodiment, the specific shape of the elastic pad 220 is not limited. The cross-section of the elastic pad 220 can be circular, elliptical, polygonal including triangles and rectangles, or even irregular shapes. Its longitudinal section can be rectangular or trapezoidal. Therefore, the elastic pad 220 can be any of the following: prism (including cuboids, cubes, triangular prisms, pentagonal prisms, etc.), cylinder, or frustum or trapezoid.

[0071] Understandably, during the bonding process of the LED chip to the driver backplane, pressure is conducted from the chip electrode of the LED chip to the backplane electrode, and then sequentially to the deformable circuit layer 23, the elastic layer 22, and the rigid substrate 21. Both the deformable circuit layer 23 and the elastic layer 22 need to deform, which requires ensuring that the deformable circuit layer 23 has sufficient length in all directions to meet the deformation requirements, i.e., providing deformation space.

[0072] In some examples, in order to give the deformable circuit layer 23 a deformable space, a material with good ductility is selected when fabricating the deformable circuit layer 23.

[0073] In some other examples, although the deformable circuit layer 23 is bendable, its ductility is generally limited. In such cases, to ensure that the deformable circuit layer 23 has sufficient deformation space, its area should have a certain redundancy. For example, please refer to... Figure 7 The drive backplate 70 shown has a deformable circuit layer 23 disposed on the elastic layer 22, which naturally has slight wrinkles and undulations. When the deformable circuit layer 23 needs to be deformed, these wrinkles or undulations can be straightened to provide deformation space.

[0074] In some examples, the elastic layer 22 includes multiple elastic pads 220, and the deformable circuit layer 23 can be arranged along the surface contour of the component formed by the bonding of the elastic pads 220 and the rigid substrate 21. Please see [link to relevant documentation]. Figure 4 , Figure 5 as well as Figure 6 As shown: Part of the deformable circuit layer 23 covers the surface of the elastic pad 220 exposed on the rigid substrate 21, while the other part is attached to the rigid substrate between adjacent elastic pads.

[0075] This embodiment also provides a display panel and a method for manufacturing the display panel. Please refer to [link to documentation]. Figure 8a As shown, the display panel 80 includes multiple LED chips 81 and a driving backplane 82. The driving backplane 82 can be any of the driving backplanes provided in the aforementioned examples. The chip electrodes of the LED chips 81 are bonded to the backplane electrodes 230 on the driving backplane 82. The LED chips 81 can emit light through the current provided by the driving circuit in the driving backplane 82. The fabrication process of this display panel 80 can be found in [reference needed]. Figure 8b and Figure 8c As shown:

[0076] S802: Provides a driver backplane and a donor substrate with multiple LED chips.

[0077] In this embodiment, the donor substrate 83 can refer to a transfer substrate, temporary substrate, transient substrate, etc., or it can be a transfer head, such as a PDMS transfer head. Please refer to [link to relevant documentation]. Figure 8c (a) In this example, taking a flip-chip LED 81, the chip electrodes of the LED chip 81 on the donor substrate 83 face away from the donor substrate 83. In some examples of this embodiment, the donor substrate 83 can simultaneously provide at least two different types of LED chips 81 to the driving backplane 82, which can improve the transfer efficiency of the LED chips 81. In some even examples, the multiple LED chips 81 on the donor substrate 83 include three different types of LED chips, such as red, green and blue chips, which can achieve full-color transfer.

[0078] For the process of providing the drive backplane 82, please refer to the description in the previous example, which will not be repeated here.

[0079] S804: Align the donor substrate with the driver backplane, with the chip electrodes of the LED chip facing each other and opposite to the backplane electrodes.

[0080] Please see Figure 8c In Figure 8(b), after obtaining the donor substrate 83 with LED chips 82, the donor substrate 83 can be aligned with the driving backplate 82. It is understood that the alignment of the donor substrate 83 and the driving backplate 82 is not an alignment of their centers or a specific vertex, but rather an alignment of the LED chips 81 on the donor substrate 83 with the chip receiving area in the driving backplate 82. Taking a flip-chip structure for the LED chips 81 as an example, the alignment of the donor substrate 83 and the driving backplate 82 is the alignment of the chip electrodes of the LED chips 81 with the backplate electrodes in the driving backplate 82. In Figure 8(b), the elastic layer 22 includes multiple elastic pads 220, and each elastic pad 220 has two electrically isolated backplate electrodes. Each LED chip 81 is opposite to one elastic pad 220, and the two chip electrodes of one LED chip 81 are aligned with the two backplate electrodes on one elastic pad 220. It is understood that in some other examples, one LED chip 81 may also correspond to two elastic pads 220. In addition, when the LED chip 81 has a vertical structure, one chip electrode of the LED chip 81 facing the driving backplate 82 is aligned with the corresponding backplate electrode on the driving backplate 82.

[0081] S806: Apply pressure toward each other to at least one of the donor substrate and the driving backplane until the chip electrode and the backplane electrode are bonded.

[0082] exist Figure 8c In step (c), pressure can be applied to the donor substrate 83, causing the donor substrate 83 to move towards the driving backplate 82 until the chip electrode of the LED chip 81 is bonded to the backplate electrode of the driving backplate 82. Figure 8c (d) In other examples, pressure may be applied to the driver backplane 82 toward the donor substrate 83 until the LED chip 81 is bonded; or pressure may be applied to both the donor substrate 83 and the driver backplane 82 toward each other to complete the bonding of the LED chip 81. Furthermore, the LED chip 81 can be either a flip-chip or a vertical chip.

[0083] S808: Remove donor substrate.

[0084] After the LED chip 81 is bonded to the driver backplane 82, the donor substrate 83 can be removed, such as... Figure 8c(e) The removal method needs to be selected according to the bonding method between the LED chip 81 and the donor substrate 83. For example, in some examples, the donor substrate 83 can be removed by laser; in other examples, the donor substrate 83 and the LED chip 81 are bonded by thermal release adhesive, so the donor substrate 83 can be removed by heating; in still other examples, the donor substrate 83 and the LED chip 81 are bonded by van der Waals forces, so the donor substrate 83 can be removed directly.

[0085] Understandably, because the backplate electrode 82 of the driving backplate 82 is disposed on the elastic layer 22, when the LED chip 81 is transferred and bonded to the driving backplate 82, the pressure applied to the LED chip 81 can be transferred to the elastic layer 22 through the backplate electrode 230, causing the elastic layer 22 to deform. The deformation of the elastic layer 22 can then compensate for the difference in bonding distance between each chip electrode and the corresponding backplate electrode 230, avoiding chip interference that would prevent some LED chip electrodes from contacting the corresponding backplate electrode 230. It also avoids the problem of some LED chips 81 being damaged and broken due to excessive pressure, thus improving the transfer and bonding yield of the LED chip 81, enhancing the quality of the display panel 80, and reducing the production cost of the display panel.

[0086] Although the LED chip 81 in Figure 8 is a flip-chip structure, this embodiment does not specifically limit the structure and type of the LED chip 81. For example, the LED chip 81 can be a vertically structured LED chip or a horizontally structured LED chip; it can be a Micro-LED chip, a Mini-LED chip, or an OLED (Organic Light-Emitting Diode) chip. Typically, the display panel 80 is a full-color display panel, so the LED chips 81 in the display panel 80 generally include chips of at least three colors: red, green, and blue. However, in some examples, in addition to these three colors, it may also include chips of other colors such as white and yellow.

[0087] The driving backplane and display panel provided in this embodiment can buffer the pressure between the chip electrode and the backplane electrode during the LED chip bonding process by setting a deformable circuit layer and an elastic layer, thus avoiding damage and breakage of the LED chip due to excessive pressure. At the same time, the deformation at each position of the deformable circuit layer and the elastic layer is related to the pressure between the chip electrode and the corresponding backplane electrode at the corresponding position. The greater the pressure, the greater the deformation, and the lower the pressure, the smaller the deformation. Therefore, the backplane electrode with less pressure will be higher and more prominent than the backplane electrode with more pressure. This facilitates more complete contact between these backplane electrodes and the corresponding chip electrodes to achieve bonding, improves the bonding effect, and increases the transfer yield of the LED chip.

[0088] Another optional embodiment of this application:

[0089] This embodiment also provides a method for manufacturing a drive backplate. Please refer to [link / reference]. Figure 9 The diagram shows the process state changes of the drive backplane fabrication method, and Figure 10 The flowchart of the method for fabricating the drive backplate is shown below:

[0090] S1002: Provides a rigid substrate.

[0091] Please see Figure 9 In (a) of this embodiment, the rigid substrate 91 may include at least one of silicon substrate, quartz substrate, sapphire substrate, glass substrate, metal substrate, and plastic substrate.

[0092] S1004: An elastic layer is fixedly installed on one side of a rigid substrate.

[0093] Please combine Figure 9 In embodiment (b), the elastic layer includes multiple elastic pads 920, and each elastic pad 920 is used to support an LED chip. Therefore, the elastic pads 920 are arranged in an array on the surface of the rigid substrate 91, and the arrangement of the elastic pads 920 determines the arrangement of the LED chips on the driving backplate 90. It is understood that in other examples of this embodiment, the elastic layer may have other structures. For example, in one example, in addition to including multiple spaced-apart elastic pads 920, the elastic layer 920 may also include an elastic sublayer disposed below each elastic pad 920 to support each elastic pad 920. The elastic pads 920 and the elastic sublayer may be integrally formed, or they may be independent of each other but fixed together by adhesives or the like. In some other examples, the elastic layer may include only a single elastic layer structure.

[0094] In this embodiment, the elastic pad 920 can be bonded to the surface of the rigid substrate 91 using adhesive. In other examples, the elastic pad 920 can be fixed to the rigid substrate 91 by snap-fitting. For example, multiple positioning grooves with the same orientation can be formed on the rigid substrate 91 by patterning, and then the elastic pad 920 can be placed into the positioning grooves to limit and fix the elastic pad 920. In some other examples, the elastic pad 920 can be fixed to the rigid substrate by snap-fitting and bonding. For example, multiple positioning grooves can be formed on the rigid substrate 91 by etching, and then the elastic pad 920 can be bonded and fixed to the positioning grooves by an adhesive layer.

[0095] S1006: A deformable circuit layer is provided on the side of the elastic layer facing away from the rigid substrate. The deformable circuit layer includes a driving circuit and multiple backplate electrodes electrically connected to the driving circuit.

[0096] After setting the elastic layer, a deformable circuit layer 93 can be further set. First, a deformable circuit layer 93 is provided. In this embodiment, an FPC or liquid metal circuit board is selected as the deformable circuit layer 93. Multiple backplane electrodes 930 are arranged in an array on one surface of the FPC or liquid metal circuit board. These backplane electrodes 930 are electrically connected to the driving circuit in the FPC or liquid metal circuit board. When setting the deformable circuit layer 93, the provided deformable circuit layer 93 can be stacked parallel to the rigid substrate 91. For example, in... Figure 9 In (c), the rigid substrate 91 is below, and the deformable circuit layer 93 is above, facing each other. The side of the rigid substrate 91 with the elastic pad 920 faces the deformable circuit layer 93, while the side of the deformable circuit layer 93 with the backplate electrode 930 faces away from the rigid substrate 91. In other words, both the side of the rigid substrate 91 with the elastic pad 920 and the side of the deformable circuit layer 93 with the backplate electrode 930 face upwards. Then, the rigid substrate 91 and the deformable circuit layer 93 are moved to move towards each other until they are joined together. Figure 9(d) In some examples of this embodiment, when setting the deformable circuit layer 93, it is only necessary to ensure that the deformable circuit layer 93 is in contact with the upper surface of the elastic layer. In other examples, when the elastic layer includes multiple elastic pads 920, after the deformable circuit layer 93 contacts the elastic layer, it is also necessary to apply pressure toward each other to at least one of the deformable circuit layer 93 and the rigid substrate 91 until the deformable circuit 93 deforms. Because the rigid substrate 91 has multiple elastic pads 920 protruding from its upper surface, the upper surface of the component formed by the rigid substrate 91 and the elastic pads 920 is not flush, but rather undulating. When the deformable circuit layer 93 is pressed, it bends along the contour of the upper surface of the component formed by the rigid substrate 91 and the elastic pads 920. Ultimately, a portion of the deformable circuit layer 93 covers the elastic pads 920 and is exposed on the surface of the rigid substrate 91, while another portion is attached to the rigid substrate 91 between adjacent elastic pads 920. Simultaneously, to ensure that the bonding pressure can be transmitted to the elastic pads 920 during the LED chip bonding process, this embodiment requires that after the deformable circuit layer 93 is set, the backplate electrode 930 is located on the surface of the elastic pads 920 facing the deformable circuit layer 93, i.e., the backplate electrode 930 is located on the elastic pads 920. Figure 9 As shown in (d) in the figure.

[0097] It is understandable that the deformable circuit layer 93 needs to deform along with the elastic layer. If the deformable circuit layer 93 itself has good ductility, then when the elastic layer deforms, the deformable circuit layer 93 can achieve a certain amount of deformation space through its own extension. However, if the deformable circuit layer 93 itself can only bend and does not have good ductility, then the deformable circuit layer 93 needs to utilize redundant area to provide deformation space. Therefore, in some examples of this embodiment, the area of ​​the deformable circuit layer 93 will be larger than the surface area of ​​the upper surface of the rigid substrate 91. For example, in Figure 9 In this context, the deformable circuit layer 93, disposed on the rigid substrate 91, undulates along the outward protrusion of the elastic pad 920. For example, in... Figure 7 In the middle, the deformable circuit layer 23 disposed on the elastic layer 22 has many folds, so after the deformable circuit layer 23 is stretched flat, its area must be larger than the upper surface area of ​​the corresponding rigid substrate 21.

[0098] The driving backplane fabrication method provided in this embodiment, by setting an elastic layer and a deformable circuit layer on a rigid substrate, allows the pressure borne by the LED chip during LED chip bonding to be transmitted to the elastic layer, achieving pressure buffering and avoiding damage to the LED chip by bonding pressure. At the same time, the compression deformation of the deformable circuit layer and elastic layer at the first LED chip bonding position also makes the backplane electrode at the subsequent LED chip bonding position relatively "protruding", thereby allowing the chip electrode of the subsequent LED chip to make full contact with the corresponding backplane electrode, avoiding chip interference problems, and improving the bonding effect and transfer yield of the LED chip.

[0099] Another optional embodiment of this application:

[0100] To make the advantages and details of the aforementioned driving backplane, display panel, and driving backplane fabrication method clearer to those skilled in the art, this embodiment will further illustrate these solutions with examples. Please refer to [link to relevant documentation]. Figure 11 The flowchart of the drive backplate fabrication shown is as follows: Figure 12 The diagram shown illustrates the process state changes of the drive backplane:

[0101] S1102: Provides a quartz substrate.

[0102] Please see Figure 12 In (a) of this embodiment, a quartz substrate 121 is used as a rigid substrate, but in other embodiments, a silicon substrate, a glass substrate, or the like can also be selected as a rigid substrate.

[0103] S1104: The quartz substrate is etched to form multiple positioning grooves.

[0104] After obtaining the quartz substrate 121, the surface of the quartz substrate can be patterned to form multiple positioning grooves 1210 with the same orientation, such as... Figure 12 As shown in (b) of this embodiment, the accommodating space inside each positioning groove 1210 is a cuboid, and the specifications of each positioning groove 1210 are the same. However, in some other examples of this embodiment, the shape of each positioning groove 1210 may be inconsistent. For example, the accommodating space inside some positioning grooves 1210 is a cube, the accommodating space inside some positioning grooves 1210 is a cylinder, and the accommodating space inside some positioning grooves 1210 is a triangular prism; or, although the shape of some positioning grooves 1210 is the same as that of other positioning grooves 1210, their size specifications are inconsistent.

[0105] For reference, when patterning the quartz substrate 121, a photoresist layer can first be coated on the upper surface of the quartz substrate 121. Then, the photoresist layer is exposed and developed according to the arrangement of the positioning grooves 1210 on the quartz substrate 121 to form a mask. The mask includes multiple cutout areas. Undoubtedly, the positions of the quartz substrate 121 corresponding to the cutout areas are the positions where the quartz substrate 121 will be etched, that is, the positions where the positioning grooves 1210 are formed. Subsequently, the quartz substrate 121 is etched through the mask to form multiple positioning grooves 1210. After the positioning grooves 1210 are formed, the mask can be removed.

[0106] S1106: An elastic pad is bonded and fixed to the bottom of the positioning groove.

[0107] After obtaining the quartz substrate 121 with the positioning groove 1210, an elastic pad 1220 can be set in the positioning groove 1210. The shape and size of the cross-section of the elastic pad 1220 match the shape and size of the cross-section of the positioning groove 1210. Simultaneously, the height of the elastic pad 1220 is greater than the depth of the positioning groove 1210. Therefore, the upper part of the elastic pad 1220 protrudes outward from the positioning groove 1210. Figure 12 (c) in the middle.

[0108] In this embodiment, before placing the elastic pad 1220 into the positioning groove 1210, an adhesive layer can be first applied to the bottom of the positioning groove 1210 using methods such as dispensing glue. Then, the elastic pad 1220 is placed into the positioning groove 1210. The adhesion of the adhesive layer further enhances the reliability of the bond between the elastic pad 1220 and the quartz substrate 121. In other examples, an adhesive layer can be first applied to the surface of the elastic pad 1220 facing the positioning groove 1210, and then the elastic pad 1220 is placed into the positioning groove 1210. In still other examples, adhesive layers can be applied to both the positioning groove 1210 and the elastic pad 1220 simultaneously, and the elastic pad 1220 is then fixed to the quartz substrate by the mutual adhesion between the two adhesive layers.

[0109] S1108: Stack the FPC with backplate electrode in parallel with the quartz substrate.

[0110] After the elastic pads 1220 are installed, an FPC 123 with multiple backplate electrodes 1230 can be provided. The FPC 123 is laid flat on top of the quartz substrate 121 with the elastic pads 1220, with the side of the quartz substrate 121 with the elastic pads 1220 and the side of the FPC with the backplate electrodes 1230 both facing upwards. Please refer to [link to relevant documentation]. Figure 12 (d) in the middle.

[0111] S1110: Apply pressure to the FPC toward the quartz substrate until the FPC deforms and adheres to the surface of the elastic pad and the quartz substrate.

[0112] Please see Figure 12 In step (e), pressure can be applied to the FPC 123, causing the FPC 123 to move toward the quartz substrate 121. After the FPC 123 comes into contact with the elastic pad 1220, the pressure continues to be applied, and the FPC 123 will deform and bend with the ups and downs of the elastic pad 1220, thereby covering the surface of the elastic pad 1220 exposed in the positioning groove 1210. At the same time, the area of ​​the FPC 123 between adjacent elastic pads 1220 is attached to the upper surface of the quartz substrate 121 in that area.

[0113] The driving backplane provided in this embodiment can improve the problems of transfer yield and LED chip reliability loss caused by substrate warping and chip height difference. When transferring LED chips to the driving backplane through transfer substrate or transfer head, the bonding of LED chips of different types and heights on the transfer equipment will not be affected by chip height difference or substrate warping. The pressure borne by each LED chip during the bonding process is basically balanced, and there will be no problem of some LED chips being crushed due to uneven pressure, while some LED chips cannot be bonded. This ensures the yield of display panel manufacturing and the reliability of display panel.

[0114] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A drive backplane, characterized by, include: Rigid substrate; A deformable circuit layer covering one side of the rigid substrate; as well as An elastic layer located between the rigid substrate and the deformable circuit layer; The deformable circuit layer includes a driving circuit and a plurality of backplate electrodes electrically connected to the driving circuit. The backplate electrodes are disposed on the side of the deformable circuit layer facing away from the rigid substrate. The elastic modulus of the elastic layer is between 1 and 800 MPa. The deformable circuit layer is either a flexible circuit board or a liquid metal circuit board.

2. The drive backplane of claim 1, wherein, The elastic layer includes a plurality of independent elastic pads; the elastic pads are fixed on the rigid substrate, and the backplate electrode is located on the side of the elastic pads away from the rigid substrate.

3. The drive backplane of claim 2, wherein, The rigid substrate has multiple positioning grooves facing the same direction, the openings of the positioning grooves face the deformable circuit, and the elastic pad is fixed in the positioning grooves.

4. The drive backplane as described in claim 2, characterized in that, A backplate electrode is disposed on one of the elastic pads, and the distance between two adjacent elastic pads is equal to the distance between two chip electrodes in the LED chip; Alternatively, one of the elastic pads may have two backplate electrodes that are electrically isolated from each other, and the distance between the two backplate electrodes is equal to the distance between the two chip electrodes in the LED chip.

5. The drive backplane as described in claim 2, characterized in that, A portion of the deformable circuit layer covers the elastic pads and is exposed on the surface of the rigid substrate, while another portion is attached to the rigid substrate between adjacent elastic pads.

6. A display panel, characterized in that, include: Multiple LED chips; as well as The drive backplate as described in any one of claims 1-5; The chip electrode of the LED chip is electrically connected to the backplate electrode in the driving backplate.

7. A method for manufacturing a display panel, characterized in that, include: A driving backplane and a donor substrate with multiple LED chips are provided. The driving backplane includes a rigid substrate, an elastic layer, and a deformable circuit layer. The elastic layer is disposed between the rigid substrate and the deformable circuit. The deformable circuit includes a driving circuit and multiple backplane electrodes electrically connected to the driving circuit. The backplane electrodes are disposed on the side of the deformable circuit layer facing away from the rigid substrate. The elastic modulus of the elastic layer is between 1 and 800 MPa. The deformable circuit layer is any one of a flexible circuit board or a liquid metal circuit board. The donor substrate is aligned with the driving backplate, and the chip electrodes of the LED chip are opposite to and facing each other with the backplate electrodes; Apply pressure toward each other to at least one of the donor substrate and the driving backplane until the chip electrode is bonded to the backplane electrode; as well as Remove the donor substrate.

8. The method for manufacturing a display panel as described in claim 7, characterized in that, The multiple LED chips include at least three different types of LED chips.

9. The method for manufacturing a display panel as described in claim 7 or 8, characterized in that, The elastic layer includes a plurality of independent elastic pads, and each elastic pad is provided with two backplate electrodes that are electrically isolated from each other; Aligning the donor substrate with the driving backplate includes aligning the two chip electrodes of the LED chip on the donor substrate with the two backplate electrodes on the same elastic pad.

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