CN115483243A

CN115483243A - Display backplane assembly, LED display module and apparatus, and related methods

Info

Publication number: CN115483243A
Application number: CN202110646462.0A
Authority: CN
Inventors: 翟峰
Original assignee: Chongqing Kangjia Photoelectric Technology Research Institute Co Ltd
Current assignee: Chongqing Kangjia Photoelectric Technology Research Institute Co Ltd
Priority date: 2021-05-31
Filing date: 2021-05-31
Publication date: 2022-12-16

Abstract

The present application relates to a display backplane assembly, an LED display module and apparatus, and related methods, the display backplane assembly including a display backplane and a planarization layer, the display backplane having a first surface with an electrode connection tab thereon. The planarization layer is stacked on the first surface; the planarization layer is provided with a plurality of accommodating holes extending along the thickness direction, and the accommodating holes correspond to the electrode connecting sheets; the plurality of accommodating holes comprise a first hole and a second hole, welding materials are filled in the first hole, and the welding materials are in contact with the electrode connecting sheet; the second hole is filled with adhesive glue. The LED chip is pre-fixed by using the adhesive glue, the welding materials are only contacted but not fixed, and at the moment, the electric connection stability test is carried out. Because the welding material is only contacted with the electrode of the LED chip but not fixed, the welding material can be prevented from being influenced by the LED chip with a dead point, and the subsequent repair of another LED chip is easier.

Description

Display backplane assembly, LED display module and apparatus, and related methods

Technical Field

The present application relates to the field of displays, and in particular, to a display backplane assembly, an LED display module and apparatus, and a related method.

Background

At present, a micro light-emitting diode (micro LED) display panel has the advantages of higher brightness, better light-emitting efficiency, lower power consumption and the like as a new generation display technology, so that the micro LED is widely used.

The Micro-LED display panel generally includes a plurality of pixel regions thereon, each pixel region including a red LED chip, a blue LED chip, and a green LED chip. In the process of preparing the display panel, three chips need to be transferred from the respective growth substrates to the display back panel. The currently adopted transfer mode is as follows: bonding the red LED chip to a temporary substrate by using the temporary substrate; then the growth substrate of the red light LED chip is stripped by laser, and the red light LED chip is transferred to a temporary substrate; and then transferring the red LED chips to the display back plate on the temporary substrate by using the transfer substrate. Blue LED chips and green LED chips were transferred separately in the same manner. The process of transferring the LED chips to the display backplane is also a process of mass soldering.

However, in the current soldering method, the electrical connection stability is detected after the soldering is completed, and the connection strength between the LED chip and the display back plate is high. If the defective pixel is detected, when the LED chip is removed, the defective pixel LED chip can be removed only by applying a large external force, the operation difficulty is high, and the solder is easily removed, so that the subsequent repair (trimming) of another LED chip to the defective pixel position is difficult.

Disclosure of Invention

In view of the above deficiencies of the prior art, an object of the present application is to provide a display backplane assembly, an LED display module apparatus, and a related method, which are used to solve the problems of difficult removal of a defective LED chip and difficult subsequent repair of another LED chip.

A first aspect of the present application provides a display backplane assembly comprising: the display back plate is provided with a first surface, and the first surface is provided with an electrode connecting sheet; a planarization layer stacked on the first surface; the planarization layer is provided with a plurality of accommodating holes extending along the thickness direction of the planarization layer, and the accommodating holes correspond to the electrode connecting sheets; the plurality of accommodating holes comprise a first hole and a second hole, and the first hole penetrates through the planarization layer along the thickness direction so that at least part of the electrode connecting sheet is exposed relative to the planarization layer; the second hole at least penetrates through one side of the planarization layer, which is far away from the display back plate; filling a welding material in the first hole so that the welding material is in contact with the electrode connecting sheet; adhesive glue is filled in the second hole; the welding material is used for electrically connecting the electrode of the LED chip and the electrode connecting sheet, and the adhesive glue is used for fixing the LED chip on the planarization layer.

The welding material is contacted with the electrode of the LED chip and is not fixed, and the electrode of the LED chip is adhered to the planarization layer through the adhesive glue, so that the LED chip is pre-fixed on the display back plate. At this time, the LED chip is already electrically connected with the display back plate, and the LED chip can be subjected to an electrical connection stability test. If the LED chip is tested to have a dead spot, the LED chip is pre-fixed by using the adhesive, so that the dead LED chip can be removed by slightly applying external force, and the operation is simpler. And because the welding material is only contacted with the electrode of the LED chip and is not fixed, the welding material can be prevented from being influenced by the LED chip with a bad point, and the follow-up repair of another LED chip is easier.

Optionally, the first holes and the second holes are alternately spaced in a direction perpendicular to a thickness direction of the planarization layer. Therefore, the contact points of the adhesive and the electrodes of the LED chip are uniform, and the pre-fixing stability of the LED chip is improved; the contact points of the welding material and the electrodes of the LED chip can be more uniform, so that the stability of electric connection can be improved, and the connection strength after subsequent welding can be improved.

Optionally, in a direction perpendicular to the thickness direction of the planarization layer, any two adjacent receiving holes have a space therebetween, and a dimension of the space in a radial direction of the receiving holes is larger than an aperture of the receiving holes. Therefore, the processing difficulty of the accommodating hole can be reduced, and the cost is reduced.

Alternatively, the following condition is satisfied between the dimension a of the space and the aperture b of the accommodation hole: a is greater than or equal to 2 times b and less than or equal to 2.5 times b. Therefore, the welding material and the LED chip can be ensured to have enough contact area, and the cost can be reduced.

Optionally, the aperture of the receiving hole on the side close to the display back plate is larger than the aperture on the side far from the display back plate. The welding material and the adhesive can be better printed by a spray printing mode, and the operation convenience is improved.

Or the aperture of the accommodating hole close to one side of the display back plate is smaller than the aperture of the accommodating hole far away from one side of the display back plate. Therefore, the contact area of the welding material and the electrode of the LED chip is large, and the electric connection strength can be increased. The contact area between the adhesive and the electrode of the LED chip is larger, so that the pre-fixing stability of the LED chip can be improved.

Optionally, the aperture of the first hole at the side close to the display back plate is larger than the aperture at the side far from the display back plate; the aperture of one side of the second hole close to the display back plate is smaller than that of one side far away from the display back plate. Therefore, the contact area between the adhesive and the electrode of the LED chip can be increased, and the stability of the LED chip in pre-fixing is enhanced; and facilitating spray printing of the solder material in the first hole.

Or the aperture of one side of the first hole close to the display back plate is smaller than that of one side far away from the display back plate; the aperture of one side of the second hole close to the display back plate is larger than that of one side far away from the display back plate. Therefore, the contact area of the welding material and the electrode of the LED chip can be increased, and the stability of the electrical connection of the LED chip is improved; and facilitating the preparation of the glue material in the second hole.

Optionally, the soldering material is flush with a surface of the planarization layer facing away from the display backplane; alternatively, the solder material protrudes with respect to the surface of the planarization layer facing away from the display backplane. Thereby, the reliability of the contact of the solder material with the electrode of the LED chip can be increased.

Optionally, the second hole also penetrates through a side of the planarization layer facing the display backplane. Therefore, the processing difficulty can be reduced, and the cost is saved.

Alternatively, the material of the planarization layer includes at least one of polymethyl methacrylate, polystyrene, a polymer derivative having a phenol group, a propylene-based polymer, an imide-based polymer, an aryl ether-based polymer, an amide-based polymer, a fluorine-based polymer, a p-xylene-based polymer, and a vinyl alcohol-based polymer.

A second aspect of the present application provides an LED display module comprising an LED chip and a display backplane assembly according to any of the first aspects of the present application; the LED chip is arranged on one side of the planarization layer, which is far away from the display backboard; the LED chip is provided with electrodes, the electrodes correspond to at least part of the first hole and at least part of the second hole, the electrodes are electrically connected with the electrode connecting sheets through welding materials, and the electrodes are connected with the planarization layer through adhesive glue.

The third aspect of the application provides an LED display device, comprising the display module of any one of the second aspects of the application.

A fourth aspect of the present application provides a method for manufacturing a display backplane assembly, comprising: preparing a planarization layer on the first surface of the display back plate; the first surface is provided with an electrode connecting sheet; forming a plurality of accommodating holes in the planarization layer along the thickness direction; the plurality of accommodating holes correspond to the electrode connecting sheets, and at least parts of the electrode connecting sheets are exposed relative to the planarization layer; the plurality of receiving holes include a first hole and a second hole; the first hole penetrates through the planarization layer along the thickness direction so that at least part of the electrode connecting sheet is exposed relative to the planarization layer; the second hole penetrates through one side, away from the display back plate, of the planarization layer along the thickness direction; filling welding materials in the first hole, wherein the welding materials are in contact with the electrode connecting sheet; and adhesive glue is filled in the second hole.

In the LED display back plate prepared by the method, the first hole is filled with the welding material, and the second hole is filled with the adhesive glue. When the LED chip is fabricated on the LED display back plate, the welding material may electrically connect the LED chip and the electrode connecting sheet but not fix the LED chip, and the adhesive may adhere the electrode of the LED chip to the planarization layer, thereby pre-fixing the LED chip on the display back plate. Because the LED chip is electrically connected with the display back plate when the LED chip is pre-fixed, the LED chip can be subjected to an electrical connection stability test after the pre-fixing is finished. If a defective pixel is detected, the defective LED chip can be removed, and another LED chip is mounted. When the broken LED chips are removed, the broken LED chips can be removed by slightly applying external force because the LED chips are pre-fixed by using the adhesive, and the operation is simpler. And because the welding material is only contacted with the electrode of the LED chip and is not fixed, the welding material can be prevented from being influenced by the LED chip with a bad point, and the follow-up repair of another LED chip is easier.

The fifth aspect of the present application provides a method for manufacturing an LED display module, including: preparing a planarization layer on a first surface of a display backplane; the first surface is provided with an electrode connecting sheet; forming a plurality of accommodating holes in the planarization layer along the thickness direction; the plurality of accommodating holes correspond to the electrode connecting sheets, and at least parts of the electrode connecting sheets are exposed relative to the planarization layer; the plurality of receiving holes include a first hole and a second hole; the first hole penetrates through the planarization layer along the thickness direction so that at least part of the electrode connecting sheet is exposed relative to the planarization layer; the second hole at least penetrates through one side of the planarization layer, which is far away from the display back plate; filling welding materials in the first hole, wherein the welding materials are in contact with the electrode connecting sheet; filling adhesive glue in the second hole; transferring the LED chip to the side of the planarization layer, which is far away from the display backboard; the LED chip is provided with electrodes, the electrodes correspond to at least part of the first hole and at least part of the second hole, the electrodes are electrically connected with the electrode connecting sheets through welding materials, and the electrodes are connected with the planarization layer through adhesive glue.

In the LED display back plate prepared by the method, the first hole is filled with the welding material, and the second hole is filled with the adhesive glue. The welding material electrically connects the LED chip and the electrode connecting sheet but is not fixed, and the adhesive glue bonds the electrode of the LED chip on the planarization layer, so that the LED chip is pre-fixed on the display back plate. Because the LED chip is electrically connected with the display back plate when the LED chip is pre-fixed, the LED chip can be subjected to an electrical connection stability test after the pre-fixing is finished. If a defective pixel is detected, the defective LED chip can be removed, and another LED chip is mounted. When the broken LED chips are removed, the broken LED chips can be removed by slightly applying external force because the LED chips are pre-fixed by using the adhesive, and the operation is simpler. And because the welding material is only contacted with the electrode of the LED chip and is not fixed, the welding material can be prevented from being influenced by the LED chip with a bad point, and the follow-up repair of another LED chip is easier.

A sixth aspect of the present application provides a repairing method, which is applied to the LED display module in the second aspect of the present application, or applied to the LED display device in the third aspect of the present application, and includes: detecting the electrical connection stability of the LED chip; under the condition that the electrical connection stability of the LED chip is detected to be abnormal, the LED chip is removed from the display back plate assembly; supplementing another LED chip to the display backboard assembly; the other LED chip is provided with an electrode, the electrode corresponds to at least part of the first hole and at least part of the second hole, the electrode is electrically connected with the electrode connecting sheet through welding materials, and the electrode is connected with the planarization layer through adhesive glue.

In this application, when rejecting the LED chip that falls, because of the LED chip utilizes the adhesive to glue and fixes in advance, consequently exert external force a little and can reject the LED chip that falls, the operation is fairly simple. And because the welding material is only contacted with the electrode of the LED chip and is not fixed, the welding material can be prevented from being influenced by the LED chip with a broken point, and the other LED chip can be easily repaired.

Drawings

Fig. 1 is a schematic structural diagram of a growth substrate provided in an embodiment of the present application.

Fig. 2 is a schematic structural view of another direction of the growth substrate according to the embodiment of the present application.

Fig. 3 is a schematic structural diagram of a temporary substrate bonded to a growth substrate according to an embodiment of the present application.

Fig. 4 is a schematic structural diagram of a process of transferring an LED chip on a growth substrate by a temporary substrate according to an embodiment of the present application.

Fig. 5 is a schematic structural diagram of the temporary substrate with the LED chip transferred thereon according to an embodiment of the present application.

Fig. 6 is a schematic structural diagram of another direction in which the temporary substrate is transferred with the LED chip according to the embodiment of the present application.

Fig. 7 is a schematic structural diagram of a transfer substrate transferring an LED chip to a display backplane according to an embodiment of the present disclosure.

Fig. 8 is a schematic structural diagram of a display backplane provided in an embodiment of the present application with LED chips transferred thereto.

FIG. 9 is a schematic structural diagram of a display backplane assembly according to an embodiment of the present application.

Fig. 10 is a schematic structural diagram of a display backplane assembly according to another embodiment of the present application.

FIG. 11 is a schematic structural diagram of a display backplane assembly according to yet another embodiment of the present application.

Fig. 12 is a schematic structural diagram of a display backplane assembly according to yet another embodiment of the present application.

Fig. 13 is a schematic structural diagram of a display backplane assembly according to yet another embodiment of the present application.

Fig. 14 is a schematic structural diagram of an LED display module according to an embodiment of the present application.

Fig. 15 is a flowchart of a process for manufacturing a display backplane assembly according to an embodiment of the present disclosure.

Fig. 16 is a schematic view of a method for manufacturing a display backplane assembly according to an embodiment of the present disclosure.

Fig. 17 is a schematic view of a manufacturing process of the LED display module according to the embodiment of the present application.

Fig. 18 is a flowchart of a manufacturing method of an LED display module according to an embodiment of the present application.

Fig. 19 is a schematic diagram illustrating a repairing process of the LED display module according to an embodiment of the present disclosure.

Fig. 20 is a flowchart of a repairing method of an LED display module according to an embodiment of the present disclosure.

Description of reference numerals: 10-growth substrate, 20-LED chip, 30-temporary substrate, 40-transfer substrate; 100-display backplane, 110-electrode connection pad 200-planarization layer, 210-accommodation hole, 211-first hole, 212-second hole, 300-solder material, 400-adhesive glue, X-thickness direction, Y-horizontal direction.

Detailed Description

To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present application are given in the accompanying drawings. This application may, however, be embodied in many 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.

Unless defined otherwise, 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 description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

Referring to fig. 1 to 6 in particular, it can be seen that fig. 1 is a schematic structural diagram of a growth substrate provided in an embodiment of the present application; FIG. 2 is a schematic structural view of another direction of a growth substrate according to an embodiment of the present disclosure;

FIG. 3 is a schematic structural diagram of a temporary substrate bonded to a growth substrate according to an embodiment of the present disclosure; FIG. 4 is a schematic structural diagram of a process of transferring an LED chip on a growth substrate by a temporary substrate according to an embodiment of the present application; fig. 5 is a schematic structural diagram of a temporary substrate with LED chips transferred thereon according to an embodiment of the present disclosure;

fig. 6 is a schematic structural diagram of the temporary substrate with LED chips transferred in another direction according to the embodiment of the present application.

In general, when the LED chips 20 are transferred to the display back panel 100, the red LED chips, the blue LED chips and the green LED chips are transferred, and the following description will be given by taking one LED chip 20 as an example, and the rest two LED chips have the same reason, which is not described in detail in this application.

The LED chip 20 is transferred to the display backplane 100 by the following steps:

step S10: a growth substrate 10 (wafer) is provided, on which growth substrate 10 LED chips 20 are grown. The LED chip 20 is then bonded to the temporary substrate 30 with the adhesive layer on the temporary substrate 30. The growth substrate 10 on the LED chip 20 is then peeled off. The LED chip 20 can thereby be transferred onto the temporary substrate 30.

Step S11: selectively adhering the LED chip 20 to the transfer substrate 40 using an adhesive layer on the transfer substrate 40; referring to fig. 7, the transfer substrate 40 is shown in fig. 7 selectively adhering the LED chips 20 on the temporary substrate 30.

Step S12: the LED chips 20 on the transfer substrate 40 are transferred onto the display backplane 100. Referring to fig. 8, a schematic diagram showing the successful transfer of the LED chips 20 on the backplane 100 is shown in fig. 8. The transfer substrate 40 is a process of transferring the LED chip 20 to the display backplane 100, and is also a process of mass soldering. Thus, after the transfer is completed, the LED chip 20 has completed the gold-indium eutectic bonding.

After the transfer is completed, that is, after the gold-indium eutectic bonding is completed, the electrical connection stability of the LED chip 20 is detected, and if a defective pixel is detected, the defective pixel LED chip 20 is removed, and then another LED chip 20 is supplemented to the defective pixel. However, in the current soldering method, the electrical connection stability is tested after the gold-indium eutectic bonding is completed, and the connection strength between the LED chip 20 and the display backplate 100 is high. If the defective pixel is detected, when the LED chip 20 is removed, the defective pixel LED chip 20 can be removed only by applying a large external force, which is difficult to operate, and the solder is easily removed, which makes it difficult to subsequently repair (trim) another LED chip 20 to the defective pixel position.

Accordingly, the present application is directed to a display backplane assembly, an LED display module and apparatus, and related methods, which are capable of solving the above-mentioned problems, and the details of which will be described in the following embodiments.

Referring to fig. 9, fig. 9 is a schematic structural diagram of a display backplane assembly according to an embodiment of the present disclosure. The display backplate subassembly that this application embodiment provided includes: a backplane 100 and a planarization layer 200 are shown. The planarization layer 200 is made of a non-conductive material.

The display back plate 100 has a first surface and a second surface opposite to each other, and with reference to the direction in fig. 9, the upper surface of the display back plate 100 is the first surface, and the lower surface is the second surface. An electrode connecting pad (pad) 110 is provided on the first surface. The planarization layer 200 is stacked on the first surface; the planarization layer 200 is provided with a plurality of receiving holes 210 extending in the thickness direction X thereof, the plurality of receiving holes 210 corresponding to the electrode connection pads 110; the plurality of receiving holes 210 include first holes 211 and second holes 212, the first holes 211 penetrating the planarization layer 200 in the thickness direction X to expose at least a portion of the electrode connecting tab 110 with respect to the planarization layer 200; the second hole 212 penetrates at least one side of the planarization layer 200 facing away from the display backplane 100 along the thickness direction X; the first hole 211 is filled with a welding material 300, and the welding material 300 is in contact with the electrode connection pad 110; the second hole 212 is filled with an adhesive 400.

The solder material 300 is used to electrically connect the electrodes of the LED chip 20 and the electrode connecting pad 110, and the adhesive 400 is used to fix the LED chip 20 on the planarization layer 200. Specifically, the LED chip 20 is disposed on a side of the planarization layer 200 away from the display backplane 100; the LED chip 20 has electrodes corresponding to at least a portion of the first hole 211 and at least a portion of the second hole 212, the electrodes being electrically connected to the electrode connection pad 110 by the solder material 300, and the electrodes being connected to the planarization layer 200 by the adhesive paste 400.

The display backplane 100 may be a Thin Film Transistor (TFT) circuit board, and the solder material 300 may be indium metal. The welding material 300 has high reliability after welding. The adhesive 400 may be NCF adhesive, which has a low cost and a suitable adhesion, and the adhesive 400 is made of non-conductive material.

The material of the planarization layer 200 includes at least one of organic materials such as polymethyl methacrylate, polystyrene, a polymer derivative having a phenol group, a propylene-based polymer, an imide-based polymer, an aryl ether-based polymer, an amide-based polymer, a fluorine-based polymer, a p-xylene-based polymer, and a vinyl alcohol-based polymer. That is, the planarization layer 200 may be made of any one of the above materials, or may be made of a mixture of two or more materials. The materials are selected, so that the materials are easy to obtain, the cost is low, and the processing is convenient.

In this embodiment, the planarization layer 200 is stacked on the display back plate 100, and the planarization layer 200 can eliminate step differences caused by differences in processing precision on the circuit back plate and facilitate connection between the display back plate 100 and the LED chips 20. Specifically, the planarization layer 200 is provided with a receiving hole 210 at a position corresponding to the electrode connection pad 110, a first hole 211 of the receiving hole 210 is filled with the welding material 300, and a second hole 212 is filled with the adhesive 400. Then, the electrodes of the LED chip 20 are aligned with the receiving holes 210, and at this time, the upper and lower sides of the welding material 300 respectively contact the electrodes of the LED chip 20 and the electrode connection pads 110, thereby achieving electrical connection of the LED chip 20 and the electrode connection pads 110. The adhesive 400 adheres the electrodes of the LED chip 20 to the planarization layer 200, thereby pre-fixing the LED chip 20 on the display backplane 100.

Since the LED chip 20 is already electrically connected to the display back plate 100 when the LED chip 20 is pre-fixed, the electrical connection stability test can be performed on the LED chip 20 after the pre-fixing is completed. If a defective pixel is detected, the defective LED chip 20 can be removed, and another LED chip 20 is mounted. When the broken LED chip 20 is removed, the LED chip 20 is pre-fixed by the adhesive 400, so that the broken LED chip 20 can be removed by applying a slight external force, and the operation is relatively simple. And because the welding material 300 is only contacted with the electrode of the LED chip 20 and is not fixed, the welding material 300 can be prevented from being influenced by the LED chip 20, and the subsequent repair of another LED chip 20 is easier.

After the repair is completed, the LED chip 20 may be covered with a soft pressing plate, and then heated and pressurized, so that the LED chip 20 completes a large amount of soldering, that is, the gold-indium eutectic bonding is completed, and at this time, the LED chip 20 and the soldering material 300 are also fixedly connected, and the electrical connection stability is ensured. The soft pressing plate is formed by arranging a layer of transfer substrate or polyurethane glue on a hard quartz substrate, so that the LED chip 20 is prevented from being crushed by soft pressing while the LED chip 20 is heated and pressurized.

It will be understood by those skilled in the art that the LED chip 20 generally has two electrodes, a positive electrode and a negative electrode, and thus each LED chip 20 needs two electrode connecting pads 110, one positive electrode connecting pad 110 and one negative electrode connecting pad 110. As shown in the drawing, two electrodes of the LED chip 20 correspond to the two electrode connection pads 110 one to one.

In some embodiments, the first holes 211 and the second holes 212 are alternately spaced in a direction perpendicular to the thickness direction X of the planarization layer 200. Referring to the direction of the figure, the X direction is the thickness direction X, and the Y direction is the horizontal direction Y, i.e. the direction perpendicular to the thickness direction X of the planarization layer 200. Because the first hole 211 is filled with the welding material 300 and the second hole 212 is filled with the adhesive 400, the first hole 211 and the second hole 212 are alternately distributed, that is, the welding material 300 and the adhesive 400 are alternately distributed at intervals, so that the contact points of the adhesive 400 and the electrodes of the LED chip 20 are more uniform, and the stability of the LED chip 20 in pre-fixing is increased; the contact points of the soldering material 300 with the electrodes of the LED chip 20 can be made more uniform, so that the stability of electrical connection can be increased, and the connection strength after subsequent soldering can be increased.

In some embodiments, in a direction perpendicular to the thickness direction X of the planarization layer 200, any two adjacent receiving holes 210 have a space therebetween, and the size of the space in the radial direction of the receiving holes 210 is larger than the aperture of the receiving holes 210. Thereby, it is possible to prevent the clearance from being excessively small, thereby causing the two adjacent accommodation holes 210 to communicate under the influence of the machining accuracy. The size of the space is larger than the diameter of the accommodating hole 210, so that the processing difficulty of the accommodating hole 210 can be reduced, and the cost is reduced.

Illustratively, the following condition is satisfied between the dimension a of the space and the aperture b of the receiving hole 210: a is greater than or equal to 2 times b and less than or equal to 2.5 times b. If the distance is too large, the number of the accommodating holes 210 that can be formed in the position of the planarization layer 200 corresponding to the electrode connecting sheet 110 is small, the amount of the filled soldering material 300 and the adhesive 400 is small, the contact area between the soldering material 300 and the electrode of the LED chip 20 is reduced, the resistance is increased, and the soldering connection strength and the adhesion stability are affected. If the interval is too small, the machining accuracy is required to be very high, and the cost is increased. The dimension a of the space is set to be between 2 and 2.5 times the aperture b of the receiving hole 210, which can ensure a sufficient contact area between the solder material 300 and the LED chip 20 and reduce the cost.

In some embodiments, as shown in fig. 9, the aperture of the receiving hole 210 on the side close to the display back plate 100 is equal to the aperture on the side far from the display back plate 100. That is, the aperture of the receiving hole 210 is uniform from top to bottom, thereby facilitating the process.

Referring to fig. 10, fig. 10 is a schematic structural diagram of a display backplane assembly according to another embodiment of the present application. In some embodiments, the aperture of the receiving hole 210 on the side close to the display back plate 100 is larger than the aperture on the side far from the display back plate 100. With reference to the direction in the drawing, the aperture of the accommodating hole 210 gradually increases from top to bottom, and has a shape with a small top and a large bottom. Therefore, when the welding material 300 is filled in the first hole 211, the nano silver can be adopted as the welding material 300, the nano silver is sprayed and printed on the planarization layer 200 through the electrofluid spraying and printing technology, after the sprayed nano silver layer is solidified, the nano silver layer is continuously sprayed and printed on the solidified nano silver layer until the whole first hole 211 is filled with the nano silver, and the structure with the small top and the big bottom is more suitable for spraying and printing the nano silver. The NCF glue material is printed in the second hole 212, and the second hole 212 is configured to have a structure with a small top and a large bottom, so that the NCF glue material is convenient to print.

Referring to fig. 11, fig. 11 is a schematic structural diagram of a display backplane assembly according to another embodiment of the present application. In other embodiments, the aperture of the receiving hole 210 near the display back-plate 100 is smaller than the aperture of the receiving hole at the side far from the display back-plate 100. That is, the hole diameter of the receiving hole 210 gradually decreases from top to bottom, and has a shape that is large in the top and small in the bottom, so that the electrode contact area between the solder material 300 and the LED chip 20 is large, and the strength of electrical connection can be increased. The contact area between the adhesive 400 and the LED chip 20 is also large, which can increase the stability of the LED chip 20.

Referring to fig. 12, fig. 12 is a schematic structural diagram of a display backplane assembly according to still another embodiment of the present application. In other embodiments, the aperture of the first hole 211 near the display back plate 100 is larger than the aperture of the first hole far from the display back plate 100; the diameter of the second hole 212 near the display back plate 100 is smaller than that of the second hole far from the display back plate 100. That is, the first holes 211 have a diameter that gradually increases from top to bottom, and the second holes 212 have a diameter that gradually decreases from top to bottom. Therefore, the contact area between the adhesive 400 and the electrode of the LED chip 20 can be increased, thereby enhancing the stability of the LED chip 20 in pre-fixing; and facilitates inkjet printing of nano silver in the first hole 211.

Referring to fig. 13, fig. 13 is a schematic structural diagram of a display backplane assembly according to still another embodiment of the present application. In other embodiments, the aperture of the first hole 211 near the display backplane 100 is smaller than the aperture of the first hole far from the display backplane 100; the aperture of the second hole 212 near the display back plate 100 is larger than that of the second hole far from the display back plate 100. That is, the first holes 211 have a diameter gradually decreasing from top to bottom, and the second holes 212 have a diameter gradually increasing from top to bottom. Thereby, the contact area of the solder material 300 with the electrode of the LED chip 20 can be increased, thereby increasing the stability of the electrical connection of the LED chip 20; and facilitates preparation of glue in the second hole 212.

In order to make the soldering material 300 reliably contact with the electrodes of the LED chip 20, the soldering material 300 is disposed flush with the surface of the planarization layer 200 facing away from the display backplane 100.

In other embodiments, in order to increase the reliability of the solder material 300 in contact with the electrodes of the LED chip 20, the solder material 300 is protruded with respect to the surface of the planarization layer 200 facing away from the display backplane 100. Illustratively, the solder material 300 may be higher than the planarization layer 2001 μm, thereby improving electrical connection reliability.

It has already been mentioned above that the second hole 212 must extend through the side of the planarization layer 200 facing away from the display backplane 100 in order to facilitate filling of the adhesive 400 and contacting of the adhesive 400 with the electrodes of the LED chip 20 to pre-fix the LED chip 20. In some embodiments, the second hole 212 may not penetrate through the side of the planarization layer 200 facing the display backplane 100, i.e., the second hole 212 may be a blind hole. In other embodiments, the second hole 212 further penetrates through a side of the planarization layer 200 facing the display backplane 100; that is, the first hole 211 and the second hole 212 are the same and penetrate through the planarization layer 200, so that the processing difficulty can be reduced and the cost can be saved.

Referring to fig. 14, fig. 14 is a schematic structural diagram of an LED display module according to an embodiment of the present disclosure. Based on the display back plate assembly provided by any of the above embodiments, the embodiment of the application further provides an LED display module, which includes an LED chip 20 and the display back plate assembly of any of the above embodiments. The LED chip 20 is disposed on a side of the planarization layer 200 away from the display backplane 100; the LED chip 20 has electrodes corresponding to at least a portion of the first hole 211 and at least a portion of the second hole 212, the electrodes being electrically connected to the electrode connection pad 110 by the solder material 300, and the electrodes being connected to the planarization layer 200 by the adhesive paste 400.

In this embodiment, the planarization layer 200 is stacked on the display back plate 100, the accommodating hole 210 is disposed on the planarization layer 200 at a position corresponding to the electrode connection pad 110, the first hole 211 of the accommodating hole 210 is filled with the solder material 300, and the second hole 212 is filled with the adhesive 400. The electrodes of the LED chip 20 are then aligned with the receiving holes 210 while the upper and lower sides of the soldering material 300 contact the electrodes of the LED chip 20 and the electrode connecting pads 110, respectively, thereby achieving electrical connection of the LED chip 20 and the electrode connecting pads 110. The adhesive 400 adheres the electrodes of the LED chip 20 to the planarization layer 200, thereby pre-fixing the LED chip 20 on the display backplane 100.

After the repair is completed, the LED chip 20 may be covered with a soft pressing plate, and then heated and pressurized, so that the LED chip 20 completes a large amount of soldering, that is, the gold-indium eutectic bonding is completed, and at this time, the LED chip 20 and the soldering material 300 are also fixedly connected, and the electrical connection stability is ensured. The soft pressing plate is formed by arranging a layer of transfer substrate 40 or polyurethane glue on a hard quartz substrate, so that the LED chip 20 is prevented from being crushed by soft pressing while the LED chip 20 is heated and pressurized.

The embodiment of the application also provides an LED display device, which comprises the display back plate assembly in any embodiment of the application. The LED display device can be an LED display screen, and a television, a computer, an industrial computer and other equipment using the LED display screen.

Referring to fig. 15 and 16, fig. 15 is a flowchart of a method for manufacturing a display backplane assembly according to an embodiment of the present disclosure; fig. 16 is a schematic view of a process for preparing a display backplane assembly according to an embodiment of the present disclosure. The following details the preparation method of the backplane assembly shown in the above example, including:

s20: preparing a planarization layer 200 on a first surface of the display backplane 100; the first surface is provided with an electrode connection pad 110. The planarization layer 200 may be prepared by a jet printing method, or the planarization layer 200 may be prepared in advance, and the planarization layer 200 may be laminated and fixed on the display back panel 100.

S21: a plurality of receiving holes 210 are opened in the planarization layer 200 in the thickness direction X. The plurality of receiving holes 210 correspond to the electrode connection pads 110, at least a portion of the electrode connection pads 110 being exposed with respect to the planarization layer 200; the plurality of receiving holes 210 includes a first hole 211 and a second hole 212; the first hole 211 penetrates the planarization layer 200 in the thickness direction X to expose at least a portion of the electrode connection pad 110 with respect to the planarization layer 200; the second hole 212 penetrates through a side of the planarization layer 200 facing away from the display backplane 100 in the thickness direction X. Specifically, the micro structure may be prepared by using a nanoimprint technology, and the micro structure is the receiving hole 210.

S22: the first hole 211 is filled with a welding material 300, and the welding material 300 is in contact with the electrode connection tab 110. Specifically, a high-precision metal mask may be used to prepare the metal indium in the first hole 211. Alternatively, nano silver may be inkjet printed in the first hole 211 as the soldering material 300.

S23: the second hole 212 is filled with an adhesive 400. Specifically, a high-precision metal mask may be used to prepare the adhesive 400 in the second hole 212.

In the LED display back panel 100 prepared by the above method, the first hole 211 is filled with the soldering material 300, and the second hole 212 is filled with the adhesive 400. When the LED chip 20 is prepared on the LED display back sheet 100, the soldering material 300 may electrically connect the LED chip 20 with the electrode connecting pad 110 but is not fixed, and the adhesive 400 may adhere the electrode of the LED chip 20 on the planarization layer 200, thereby pre-fixing the LED chip 20 on the display back sheet 100. Since the LED chip 20 is already electrically connected to the display back plate 100 when the LED chip 20 is pre-fixed, the electrical connection stability test can be performed on the LED chip 20 after the pre-fixing is completed. If a defective pixel is detected, the defective LED chip 20 can be removed, and another LED chip 20 is mounted. When the broken LED chip 20 is removed, the LED chip 20 is pre-fixed by the adhesive 400, so that the broken LED chip 20 can be removed by applying a slight external force, and the operation is relatively simple. And because the welding material 300 is only contacted with the electrode of the LED chip 20 and is not fixed, the welding material 300 can be prevented from being influenced by the LED chip 20, and the subsequent repair of another LED chip 20 is easier.

Referring to fig. 17 and 18, fig. 17 is a schematic view illustrating a manufacturing process of an LED display module according to an embodiment of the present disclosure; fig. 18 is a flowchart of a method for manufacturing an LED display module according to an embodiment of the present application. The following details the preparation method of the LED display module, including:

s30: preparing a planarization layer 200 on a first surface of the display backplane 100; the first surface is provided with an electrode connection pad 110. The planarization layer 200 may be prepared by a spray printing method, or the planarization layer 200 may be prepared in advance, and the planarization layer 200 may be laminated and fixed on the display back panel 100.

S31: forming a plurality of receiving holes 210 in the planarization layer 200 along the thickness direction X; the plurality of receiving holes 210 correspond to the electrode connection pads 110, at least a portion of the electrode connection pads 110 being exposed with respect to the planarization layer 200; the plurality of receiving holes 210 includes a first hole 211 and a second hole 212; the first hole 211 penetrates the planarization layer 200 in the thickness direction X to expose at least a portion of the electrode connecting tab 110 with respect to the planarization layer 200; the second hole 212 penetrates through a side of the planarization layer 200 facing away from the display backplane 100 in the thickness direction X. Specifically, the micro structure may be prepared by using a nanoimprint technology, and the micro structure is the receiving hole 210.

S32: the first hole 211 is filled with a welding material 300, and the welding material 300 is in contact with the electrode connection tab 110. Specifically, a high-precision metal mask may be used to prepare the metal indium in the first hole 211. Alternatively, nano silver may be inkjet printed in the first hole 211 as the soldering material 300.

S33: the second hole 212 is filled with an adhesive 400. Specifically, a high-precision metal mask may be used to prepare the adhesive 400 in the second hole 212.

S34: the LED chip 20 is transferred to the side of the planarization layer 200 facing away from the display backplane 100. The LED chip 20 has electrodes corresponding to at least a part of the first hole 211 and at least a part of the second hole 212, the electrodes being electrically connected to the electrode connecting pad 110 by the solder material 300, and the electrodes being connected to the planarization layer 200 by the adhesive paste 400.

In the LED display back panel 100 prepared by the above method, the first hole 211 is filled with the soldering material 300, and the second hole 212 is filled with the adhesive 400. The soldering material 300 electrically connects the LED chip 20 with the electrode connecting pad 110 but is not fixed, and the adhesive 400 adheres the electrode of the LED chip 20 to the planarization layer 200, thereby pre-fixing the LED chip 20 on the display back sheet 100. Since the LED chip 20 is already electrically connected to the display back plate 100 when the LED chip 20 is pre-fixed, the electrical connection stability test can be performed on the LED chip 20 after the pre-fixing is completed. If a defective pixel is detected, the defective LED chip 20 can be removed, and another LED chip 20 is mounted. When the broken LED chip 20 is removed, the LED chip 20 is pre-fixed by the adhesive 400, so that the broken LED chip 20 can be removed by applying a slight external force, and the operation is relatively simple. And because the welding material 300 is only contacted with the electrode of the LED chip 20 and is not fixed, the welding material 300 can be prevented from being influenced by the LED chip 20, and the subsequent repair of another LED chip 20 is easier.

Referring to fig. 19 and 20, fig. 19 is a schematic diagram illustrating a repairing process of an LED display module according to an embodiment of the present disclosure; fig. 20 is a flowchart of a repairing method of an LED display module according to an embodiment of the present disclosure. Based on the LED display module in the foregoing embodiment, an embodiment of the present application further provides a repairing method, including:

s40: the electrical connection stability of the LED chip 20 is checked.

S41: in the case where the electrical connection stability of the LED chip 20 is detected to be abnormal, the LED chip 20 is removed from the display backplane assembly.

S42: and supplementing another LED chip 20 to the display backplane assembly. The other LED chip 20 has electrodes corresponding to at least a part of the first hole 211 and at least a part of the second hole 212, the electrodes being electrically connected to the electrode connecting pad 110 by the solder material 300, and the electrodes being connected to the planarization layer 200 by the adhesive paste 400.

When the broken LED chip 20 is removed, the LED chip 20 is pre-fixed by the adhesive 400, and thus the broken LED chip 20 can be removed by applying a slight external force, which makes the operation relatively simple. And since the solder material 300 is not fixed but only in contact with the electrodes of the LED chip 20, the solder material 300 can be prevented from being affected by the LED chip 20, and it is easy to repair another LED chip 20.

It should be understood that the application of the present application is not limited to the above examples, and that modifications or changes may be made by those skilled in the art based on the above description, and all such modifications and changes are intended to fall within the scope of the appended claims.

Claims

1. A display backplane assembly, comprising:

the display back plate is provided with a first surface, and the first surface is provided with an electrode connecting sheet;

a planarization layer stacked on the first surface; the planarization layer is provided with a plurality of accommodating holes extending in the thickness direction thereof, and the plurality of accommodating holes correspond to the electrode connecting sheets; the plurality of accommodating holes include a first hole and a second hole, the first hole penetrating the planarization layer in a thickness direction to expose at least a portion of the electrode connecting tab with respect to the planarization layer; the second hole at least penetrates through one side of the planarization layer, which faces away from the display back plate; filling a welding material in the first hole so that the welding material is in contact with the electrode connecting sheet; adhesive glue is filled in the second hole;

the welding material is used for electrically connecting the electrode of the LED chip and the electrode connecting sheet, and the adhesive is used for fixing the LED chip on the planarization layer.

2. The display backplane assembly of claim 1, wherein the first holes and the second holes are alternately spaced apart in a direction perpendicular to a thickness direction of the planarization layer.

3. The display backplane assembly of claim 1, wherein any two adjacent receiving holes have a space therebetween in a direction perpendicular to a thickness direction of the planarization layer, the space having a size along a radial direction of the receiving holes larger than an aperture of the receiving holes.

4. The display backplane assembly of claim 1, wherein the receiving hole has a larger aperture on a side of the receiving hole proximate to the display backplane than on a side of the receiving hole distal to the display backplane;

or the aperture of one side of the accommodating hole close to the display back plate is smaller than the aperture of one side far away from the display back plate;

or the aperture of one side of the first hole close to the display back plate is larger than that of one side far away from the display back plate; the aperture of one side, close to the display back plate, of the second hole is smaller than that of one side, far away from the display back plate, of the second hole;

or the aperture of one side of the first hole close to the display back plate is smaller than the aperture of one side far away from the display back plate; the aperture of one side, close to the display back plate, of the second hole is larger than that of one side, far away from the display back plate, of the second hole.

5. The display backplane assembly of claim 1, wherein the solder material is flush with a surface of the planarization layer facing away from the display backplane;

alternatively, the solder material protrudes with respect to a surface of the planarization layer facing away from the display backplane.

6. The display backplane assembly of claim 1, wherein the second aperture further extends through a side of the planarization layer facing the display backplane.

7. An LED display module comprising an LED chip and the display backplane assembly of any one of claims 1 to 6;

the LED chip is arranged on one side of the planarization layer, which is far away from the display back plate; the LED chip is provided with an electrode, the electrode corresponds to at least part of the first hole and at least part of the second hole, the electrode is electrically connected with the electrode connecting sheet through the welding material, and the electrode is connected with the planarization layer through the adhesive glue.

8. An LED display device, comprising the display module set according to claim 7.

9. A method for preparing a display backplane assembly, comprising:

preparing a planarization layer on the first surface of the display back plate; the first surface is provided with an electrode connecting sheet;

forming a plurality of accommodating holes in the planarization layer along the thickness direction of the planarization layer; the plurality of accommodating holes correspond to the electrode connecting sheets, and at least parts of the electrode connecting sheets are exposed relative to the planarization layer; the plurality of receiving holes includes a first hole and a second hole; the first hole penetrates through the planarization layer in the thickness direction so that at least part of the electrode connecting sheet is exposed relative to the planarization layer; the second hole at least penetrates through one side, facing away from the display back plate, of the planarization layer;

filling a welding material in the first hole, wherein the welding material is in contact with the electrode connecting sheet;

and filling adhesive glue in the second hole.

10. A repairing method applied to the LED display module set in claim 7 or the LED display device set in claim 8, wherein the repairing method comprises:

detecting the electrical connection stability of the LED chip;

under the condition that the electrical connection stability of the LED chip is detected to be abnormal, the LED chip is removed from the display back plate assembly;

supplementing another LED chip to the display back plate assembly; the other LED chip is provided with an electrode, the electrode corresponds to at least part of the first hole and at least part of the second hole, the electrode is electrically connected with the electrode connecting sheet through the welding material, and the electrode is connected with the planarization layer through the adhesive glue.