Selective transfer method of LED chip, light-emitting substrate and display panel

Abstract

The application provides a selective transfer method of an LED chip, a light-emitting substrate and a display panel. The selective transfer method of the LED chip comprises the following steps: arranging a plurality of first electrode layers on a first transparent substrate; arranging a barrier wall on each first electrode layer to form a containing groove; adding liquid crystals with different threshold voltages into each containing groove; arranging a second electrode layer on a second transparent substrate; assembling the first transparent substrate and the second transparent substrate together to form a temporary substrate; coating a photolysis adhesive layer on one side of the temporary substrate; bonding an LED chip on the photolysis adhesive layer and arranging the LED chip to correspond to the first electrode layer; providing a transfer member connected with the LED chip; and using a laser to irradiate the temporary substrate from the side of the temporary substrate away from the photolysis adhesive layer, and transferring the LED chip separated from the photolysis adhesive layer to a driving backplane through the transfer member. The application can be realized by using common laser equipment, the equipment has high maturity, and the purchase cost of the equipment is lower.

Description

Technical Field

[0001] The present invention relates to the field of display technology, and in particular to a selective transfer method of an LED chip, a light-emitting substrate and a display panel. Background Art

[0002] With the advancement of optoelectronic display technology and semiconductor manufacturing, OLED and LCD display technologies have entered mass production, and micro LED display technology is also under development. Micro LED display technology is considered the best display technology of the future due to its high stability, long life, better display quality, and higher resolution. The production of micro LED panels requires transferring millions to tens of millions of micro LED chips from the growth substrate to the driver backplane, a process known as mass transfer. To save costs, the required LED chips are produced as densely as possible on the LED growth substrate, keeping the inter-chip spacing A as small as possible. However, the inter-pixel spacing B on the display driver backplane is determined by the resolution and display size and is often greater than A (to facilitate transfer, B is generally an integer multiple of A). This results in a mismatch between the inter-pixel spacing on the LED growth substrate and the final inter-pixel spacing on the driver backplane. During mass transfer, all chips on the LED growth substrate cannot be transferred to the backplane at once. Instead, LED chips with a matching inter-chip spacing must be selected from the LED growth substrate for transfer. However, at present, the use of lasers for selective transfer requires special laser equipment that can selectively irradiate specific locations. This equipment is immature and very expensive.

[0003] In view of this, it is necessary to provide a new selective transfer method of LED chips, a light-emitting substrate and a display panel to solve or at least alleviate the above technical defects. Summary of the Invention

[0004] The main purpose of the present invention is to provide a selective transfer method of LED chips, a light-emitting substrate and a display panel, aiming to solve the technical problems of low maturity and high cost of selective transfer equipment of LED chips in the prior art.

[0005] To achieve the above object, according to one aspect of the present invention, a method for selectively transferring an LED chip is provided. The method for selectively transferring an LED chip comprises the following steps:

[0006] Providing a first transparent substrate, disposing a plurality of first electrode layers on the first transparent substrate; disposing a retaining wall on each of the first electrode layers, each retaining wall forming a receiving groove with the first transparent substrate;

[0007] Adding liquid crystals with different threshold voltages into each of the holding tanks; wherein each holding tank is filled with liquid crystals with one threshold voltage;

[0008] Providing a second transparent substrate, and disposing a second electrode layer on the second transparent substrate; assembling the first transparent substrate and the second transparent substrate face to face to form a transient substrate; wherein the first electrode layer is disposed facing the second electrode layer;

[0009] Coating a photolytic adhesive layer on one side of the temporary substrate, bonding an LED chip to the photolytic adhesive layer so that the LED chip is disposed corresponding to the first electrode layer;

[0010] Providing a transfer member connected to the LED chip;

[0011] Laser is used to irradiate the transient substrate from the side of the transient substrate away from the photolytic layer; the first electrode layer and the second electrode layer are energized, and the voltage difference between the first electrode layer and the second electrode layer is set to the threshold voltage of the liquid crystal. The LED chip separated from the photolytic layer is transferred to the driving backplane through the transfer member.

[0012] In one embodiment, a plurality of different threshold voltages are arranged in ascending order to form a threshold voltage set, wherein the threshold voltage set includes a minimum threshold voltage having the smallest threshold voltage and a maximum threshold voltage having the largest threshold voltage. The step of setting the voltage difference between the first electrode layer and the second electrode layer to be the threshold voltage of the liquid crystal and transferring the LED chip separated from the photoresist layer to the driver backplane via a transfer member includes:

[0013] The voltage difference between the first electrode layer and the second electrode layer is increased in stages so that the voltage difference traverses the threshold voltages of the threshold voltage set in sequence from the minimum threshold voltage to the maximum threshold voltage, and each threshold voltage corresponds to the decomposition of the photolytic glue layer connected to the LED chip, until all the LED chips are transferred to the driving backplane in batches through the transfer member.

[0014] In one embodiment, the difference between two adjacent threshold voltages in the threshold voltage set is greater than or equal to 1V.

[0015] In one embodiment, the step of assembling the first transparent substrate and the second transparent substrate facing each other to form a transient substrate includes:

[0016] A first polarizer is disposed on a side of the first transparent substrate facing away from the first electrode layer, and a second polarizer is disposed on a side of the second transparent substrate facing away from the second electrode layer, and the first transparent substrate and the second transparent substrate are assembled together facing each other to form a transient substrate; wherein the polarization direction of the first polarizer is orthogonal to the polarization direction of the second polarizer; or

[0017] Assembling the first transparent substrate and the second transparent substrate together with the first polarizer arranged on the side of the first transparent substrate away from the first electrode layer and the second polarizer arranged on the side of the second transparent substrate away from the second electrode layer to form a temporary substrate; wherein the polarization direction of the first polarizer is orthogonal to the polarization direction of the second polarizer.

[0018] In an embodiment, the step of coating a photodegradable adhesive layer on one side of the temporary substrate comprises:

[0019] coating a photodegradable adhesive layer on the side of the first polarizer away from the first transparent substrate;

[0020] the step of coating a photodegradable adhesive layer on one side of the temporary substrate comprises:

[0021] the step of irradiating the temporary substrate with laser from the side of the temporary substrate away from the photodegradable adhesive layer comprises:

[0022] irradiating the second polarizer with laser from the side of the second polarizer away from the second transparent substrate.

[0023] In an embodiment, the step of coating a photodegradable adhesive layer on one side of the temporary substrate comprises:

[0024] coating a photodegradable adhesive layer on the side of the second polarizer away from the second transparent substrate;

[0025] the step of coating a photodegradable adhesive layer on one side of the temporary substrate comprises:

[0026] the step of irradiating the temporary substrate with laser from the side of the temporary substrate away from the photodegradable adhesive layer comprises:

[0027] irradiating the first polarizer with laser from the side of the first polarizer away from the first transparent substrate.

[0028] In an embodiment, the step of adding liquid crystal with different threshold voltages into each of the accommodating grooves further comprises the step of:

[0029] providing an alignment film in the accommodating grooves.

[0030] In an embodiment, the step of providing a transfer member connected with the LED chip comprises:

[0031] providing a transfer substrate, providing an adhesive layer on one side of the transfer substrate to form a transfer member, and bonding the adhesive layer with the LED chip; wherein the adhesion between the adhesive layer and the LED chip is less than the adhesion between the photodegradable adhesive layer and the LED chip.

[0032] According to another aspect of the present application, the present application further provides a light-emitting substrate, which comprises a driving backboard and a plurality of LED chips arranged on one side of the driving backboard, and the LED chips are transferred by the selective transfer method of the LED chips as described above.

[0033] According to another aspect of the present application, the present application further provides a display panel, which comprises a housing and the light-emitting substrate as described above.

[0034] In the above solution, the selective transfer method of the LED chips of the present application comprises the following steps: providing a first transparent substrate, arranging a plurality of first electrode layers on the first transparent substrate; arranging a barrier wall on each first electrode layer, and each barrier wall forms a containing groove with the first transparent substrate; adding liquid crystals with different threshold voltages into each containing groove; wherein, one kind of liquid crystal with a threshold voltage is added into each containing groove; providing a second transparent substrate, arranging a second electrode layer on the second transparent substrate; assembling the first transparent substrate and the second transparent substrate together to form a temporary substrate, wherein the first electrode layer is arranged to face the second electrode layer; coating a photolysis adhesive layer on one side of the temporary substrate, bonding an LED chip on the photolysis adhesive layer and arranging the LED chip to correspond to the first electrode layer; providing a transfer member connected with the LED chip; using a laser to irradiate the temporary substrate from the side of the temporary substrate away from the photolysis adhesive layer; and applying power to the first electrode layer and the second electrode layer, and setting the pressure difference of the first electrode layer and the second electrode layer as the threshold voltage of the liquid crystal, and transferring the LED chip separated from the photolysis adhesive layer to a driving backboard through the transfer member. The state of the liquid crystal with a threshold voltage less than the pressure difference can be changed to a light-transmitting state by setting the size of the pressure difference, and the photolysis adhesive layer at the corresponding position is decomposed to release the corresponding LED chip, so as to realize batch transfer or selective transfer of the LED chips. The present application uses ordinary laser equipment, without the need to use special laser equipment, and the equipment maturity is higher and the equipment purchase cost is lower. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained according to the structures shown in the drawings without creative labor for those skilled in the art.

[0036] Figure 1 The flowchart of the selective transfer method of the LED chips of the first embodiment of the present application;

[0037] Figure 2 The top view structural schematic diagram of the first transparent substrate and the first electrode layer of the embodiment of the present application;

[0038] Figure 3 Schematic diagram of the cross-sectional structure of the first transparent substrate and the first electrode layer according to an embodiment of the present invention;

[0039] Figure 4 This is a schematic top view of the structure of the first transparent substrate, the retaining wall and the first electrode layer according to an embodiment of the present invention;

[0040] Figure 5 Schematic diagram of the cross-sectional structure of the first transparent substrate, the retaining wall and the first electrode layer according to an embodiment of the present invention;

[0041] Figure 6 For Figure 5 A schematic diagram of a structure in which liquid crystal is added into a holding tank;

[0042] Figure 7 A schematic diagram of the structure of assembling a first substrate and a second substrate to form a transient substrate;

[0043] Figure 8 Schematic diagram of the structure of setting a photolytic adhesive layer and LED chip on a transient substrate;

[0044] Figure 9 A schematic diagram of the structure for connecting the transfer piece to the LED chip;

[0045] Figure 10 for Figure 9 Schematic diagram of the structure in which part of the liquid crystal changes to a light-transmitting state after being irradiated by laser;

[0046] Figure 11 Schematic diagram of the structure for transferring the released LED chip to the driver backplane;

[0047] Figure 12 Schematic diagram of the process of selectively transferring LED chips according to the second embodiment of the present invention;

[0048] Figure 13 1 is a schematic flow chart of a method for selectively transferring LED chips according to a third embodiment of the present invention;

[0049] Figure 14 1 is a schematic flow chart of a method for selectively transferring LED chips according to a fourth embodiment of the present invention;

[0050] Figure 15 FIG. 4 is a flow chart of a selective transfer method for LED chips according to a fifth embodiment of the present invention.

[0051] Description of Figure Numbers:

[0052] 1. First transparent substrate; 2. Second transparent substrate; 3. First electrode layer; 31. ITO electrode; 3. ITO trace; 4. Second electrode layer; 5. Retaining wall; 6. Liquid crystal; 7. Photolytic adhesive layer; 8. Transfer part; 81. Transfer substrate; 82. Adhesive layer; 9. Driver backplane; 91. Solid crystal; 10. First polarizer; 11. LED chip; 12. Second polarizer; 13. Connector; 14. Receiving groove.

[0053] The realization of the objectives, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0054] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0055] It should be noted that all directional indications (such as up, down, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0056] In addition, the terms "first," "second," and so on, used in this disclosure are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, features specified as "first" or "second" may explicitly or implicitly include at least one of these features.

[0057] Moreover, the technical solutions between the various embodiments of the present invention may be combined with each other, but this must be based on the fact that ordinary technicians in this field can implement them. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0058] According to one aspect of the present invention, the present invention provides a method for selectively transferring an LED chip, referring to Figure 1 , Figure 1 FIG. 1 is a flow chart of a method for selectively transferring LED chips according to a first embodiment of the present invention. The method for selectively transferring LED chips includes the following steps:

[0059] S100 , providing a first transparent substrate 1 , disposing a plurality of first electrode layers 3 on the first transparent substrate 1 ; disposing a retaining wall 5 on each first electrode layer 3 , each retaining wall 5 forming a receiving groove 14 with the first transparent substrate 1 ;

[0060] Combined with reference Figures 2 to 5 The first transparent substrate 1 is transparent and can transmit laser light. It can be made of sapphire, quartz, or glass. A first electrode layer 3 is formed on one side of the first transparent substrate 1 by film formation or photolithography. The first electrode layer 3 can be an ITO layer (indium tin oxide layer, full name in English: Indium Tin Oxide). The ITO layer is a transparent conductive layer. The first electrode layer 3 can include an ITO electrode 31 and an ITO trace 32. The size and shape of the pattern are roughly the same as the size and shape of the LED chip 11, and the position corresponds to the LED chip 11 that is subsequently transferred to the transient substrate. The ITO trace 3 is used to transmit electrical signals and is connected to the ITO electrode 31. The number of first electrode layers 3 here is multiple, and the multiple first electrode layers 3 can be arranged vertically or horizontally, or in a combination of a horizontal and vertical arrangement. The retaining wall 5 can be formed by coating an organic material and then photolithography. The organic material can be PI (full name in English: Polyimide) or PMMA (full name in English: polymethylmethacrylate). A retaining wall 5 is formed on each first electrode layer 3. The retaining wall 5 can be in the shape of a side frame, such as a side frame similar to a cube or a cylinder. The number of retaining walls 5 is equal to the number of first electrode layers 3 and is arranged in a one-to-one correspondence. Specifically, a retaining wall 5 can be formed on the periphery of the ITO electrode 31 to surround the ITO electrode 31. Each retaining wall 5 forms a receiving groove 14 with the first transparent substrate 1, and an ITO electrode 31 is provided at the bottom of the receiving groove 14.

[0061] S200 , adding liquid crystals 6 with different threshold voltages into each containing groove 14 ; wherein, liquid crystals 6 with one threshold voltage are added into each containing groove 14 .

[0062] Combined with reference Figure 6 There are multiple receiving slots 14, and liquid crystals 6 with different threshold voltages can be added to each receiving slot 14 as needed. However, only liquid crystals 6 with one threshold voltage can be added to each receiving slot 14. The specific number of transfers depends on the number of transfers. For example, if four transfers are required, liquid crystals 6 with four different threshold voltages can be added to the receiving slots 14. The multiple receiving slots 14 can be divided into four sections, each section also containing multiple receiving slots 14. Each receiving slot 14 in each section can be filled with liquid crystals 6 with the same threshold voltage, while the receiving slots 14 in different sections can be filled with liquid crystals 6 with different threshold voltages. This design facilitates the subsequent batch transfer of LED chips by adjusting the threshold voltage.

[0063] S300 , providing a second transparent substrate 2 , and disposing a second electrode layer 4 on the second transparent substrate 2 ; assembling the first transparent substrate 1 and the second transparent substrate 2 facing each other to form a transient substrate; wherein the first electrode layer 3 is disposed facing the second electrode layer 4 .

[0064] Combined with reference Figure 7 Similar to the first transparent substrate 1, the second transparent substrate 2 is also transparent and can transmit laser light. It can be made of sapphire, quartz or glass. A second electrode layer 4 is formed on one side of the second transparent substrate 2 by film formation. The second electrode layer 4 here can cover the second transparent substrate 2 as a whole layer, or can be designed into a required pattern. The design of the first electrode layer 3 and the second electrode layer 4 is mainly to facilitate the subsequent introduction of electrical signals to form a voltage difference. The first transparent substrate 1 and the second transparent substrate 2 are assembled together face to face, and can be connected by connectors 13 on all sides, and then sealed with frame glue on all sides to form a component, which is named a transient substrate. Specifically, the second electrode layer 4 is in contact with the retaining wall 5 and can cover the opening of the retaining wall 5 to enclose the liquid crystal 6 in the receiving groove 14.

[0065] S400 , coating a photolytic adhesive layer 7 on one side of the transient substrate, and bonding the LED chip 11 to the photolytic adhesive layer 7 so that the LED chip 11 is disposed corresponding to the first electrode layer 3 ;

[0066] Combined with reference Figure 8 The photosol can be decomposed under the irradiation of laser. The LED chip 11 is bonded to the photosol layer 7 so that after the photosol is decomposed, the LED chip 11 at the corresponding position of the decomposed photosol can be removed, thereby realizing the selective transfer of the LED chips 11 in batches. Because the first electrode layer 3 is located on the bottom surface of the receiving groove 14, the receiving groove 14 is provided with liquid crystal 6. By arranging the LED chip 11 corresponding to the first electrode layer 3, the LED chip 11 can actually be arranged corresponding to the liquid crystal 6. Specifically, there are multiple LED chips 11, generally tens of thousands, and each LED chip 11 corresponds to a liquid crystal 6 in the receiving groove 14. In this way, when the liquid crystal 6 is deflected to a light-transmitting state, the portion of the photosol layer 7 corresponding to the liquid crystal 6 can be decomposed to release the corresponding LED chip 11, thereby facilitating the subsequent transfer of the LED chip 11 through the transfer member 8.

[0067] S500 , providing a transfer member 8 to connect with the LED chip 11 .

[0068] Combined with reference Figure 9 A transfer member 8 is connected to the side of the LED chip 11 facing away from the photolytic adhesive layer 7 so that the corresponding LED chip 11 can be transferred after the photolytic adhesive layer 7 decomposes.

[0069] In step S600, a laser is used to irradiate the transient substrate from the side of the transient substrate away from the photolytic layer 7. The first electrode layer 3 and the second electrode layer 4 are energized, and the voltage difference between the first electrode layer 3 and the second electrode layer 4 is set to the threshold voltage of the liquid crystal 6. The LED chip 11 separated from the photolytic layer 7 is transferred to the driving backplane 9 through the transfer member 8.

[0070] Combined with reference Figure 10 and Figure 11 , the laser is directed toward the transient substrate from the side away from the photoresist layer 7. Figure 9 or Figure 10 As shown by the middle arrow A, in this way, the laser needs to at least pass through the first transparent substrate 1, the liquid crystal 6, and the second transparent substrate 2 before it can be incident on the photolytic glue layer 7. Since the first electrode layer 3, the second electrode layer 4, the first transparent substrate 1 and the second transparent substrate 2 are all transparent and will not block the propagation of the laser, the main thing that blocks the laser is the liquid crystal 6. In the initial non-powered state, the liquid crystal 6 is in an opaque state, so the laser cannot be incident on the photolytic glue layer 7, and the corresponding LED chip 11 cannot be transferred. Therefore, an electrical signal can be passed through the first electrode layer 3 and the second electrode layer 4, so that a voltage difference is formed between the first electrode layer 3 and the second electrode layer 4. When the voltage difference is greater than or equal to the threshold voltage of a certain type of liquid crystal 6, the corresponding type of liquid crystal 6 will be biased into a transparent state, such as Figure 10 The left part of the liquid crystal 6, and because there are multiple threshold voltages of the liquid crystal 6, when the pressure difference is less than the threshold voltage of the liquid crystal 6, the corresponding liquid crystal 6 will not deflect, such as Figure 10 The right-side portion of the liquid crystal 6 is in an opaque state. When the liquid crystal 6 changes to a translucent state, the laser light can decompose the photolytic layer 7 corresponding to the portion of the liquid crystal 6, releasing the LED chip 11 in the decomposed portion of the photolytic layer 7. The released LED chip 11 can then be transferred using the transfer member 8. The photolytic layer 7 corresponding to the opaque liquid crystal 6 will not decompose, so the LED chip 11 in the position where the photolytic layer 7 has not decomposed remains on the photolytic layer 7. Therefore, this method can be used to transfer the LED chip 11 in the position corresponding to the liquid crystal 6 with a lower threshold voltage. The driver backplane 9 is provided with a die-bonding point 91, which is connected to the pins of the LED chip 11.

[0071] In the above-described embodiment of the present invention, the magnitude of the pressure difference can be set to convert the liquid crystal 6 state below the threshold voltage of the pressure difference into a light-transmitting state, thereby decomposing the photolytic layer 7 at the corresponding position to release the corresponding LED chip 11, thereby achieving batch transfer or selective transfer of the LED chips 11. This application can use ordinary laser equipment, and does not require special laser equipment. The equipment is more mature and the equipment purchase cost is also lower.

[0072] In one embodiment, a plurality of different threshold voltages are arranged in order from small to large to form a threshold voltage set, wherein the threshold voltage set includes a minimum threshold voltage with the smallest threshold voltage and a maximum threshold voltage with the largest threshold voltage. Figure 12 , Figure 12 FIG. 5 is a flow chart of a method for selectively transferring LED chips according to a second embodiment of the present invention. Step S600 includes:

[0073] S601, increase the voltage difference between the first electrode layer 3 and the second electrode layer 4 in stages, so that the voltage difference traverses the threshold voltages of the threshold voltage set from the minimum threshold voltage to the maximum threshold voltage, and each threshold voltage corresponds to the decomposition of the photolytic glue layer 7 connected to the LED chip 11, until all the LED chips 11 are transferred to the driving backplane 9 in batches through the transfer member 8.

[0074] When the voltage differential applied across the liquid crystal 6 reaches a certain value, the liquid crystal 6 will transition from an opaque state to a translucent state. This value is the threshold voltage of the liquid crystal 6. The liquid crystals 6 with different threshold voltages added in step S200 are arranged sequentially from the smallest threshold voltage to form a threshold voltage set. Within the threshold voltage set are a number of discrete threshold voltages. The voltage differential between the first electrode layer 3 and the second electrode layer 4 is first controlled to a minimum threshold voltage. This will cause the liquid crystal 6 corresponding to the minimum threshold voltage to transition to a translucent state. Laser light passes through the position of the liquid crystal 6 at the minimum threshold voltage, causing the corresponding photolytic layer 7 to decompose, releasing the LED chips 11 corresponding to this portion of the photolytic layer 7. The transfer member 8 is then removed, allowing a portion of the LED chips 11 to be transferred to the driver backplane 9. The voltage difference between the first electrode layer 3 and the second electrode layer 4 is then increased until the voltage difference reaches the second smallest threshold voltage. The liquid crystal 6 corresponding to the second smallest threshold voltage will transition to a light-transmitting state, and the photolytic layer 7 corresponding to the position of the liquid crystal 6 at the second smallest threshold voltage will decompose, releasing the LED chips 11 corresponding to this portion of the photolytic layer 7. The transfer member 8 is then removed to transfer a portion of the LED chips 11 to the driver backplane 9. This cycle continues until the voltage difference between the first electrode layer 3 and the second electrode layer 4 reaches the maximum threshold voltage, at which point the last batch of LED chips 11 is transferred to the driver backplane 9. This cycle repeats to achieve the selective transfer of the LED chips 11. It should be noted that each transferred LED chip 11 does not move to the same driver backplane 9.

[0075] To more clearly illustrate the embodiments of the present invention, a specific example is now provided. Assume that four liquid crystals 6 with threshold voltages of 1V, 2V, 3V, and 4V are added. The voltage difference between the first electrode layer 3 and the second electrode layer 4 is first controlled to 1V. This causes the liquid crystal 6 corresponding to the 1V threshold voltage to transition to a light-transmitting state. The photolytic layer 7 corresponding to the position of the liquid crystal 6 with the 1V threshold voltage decomposes, releasing the LED chips 11 corresponding to the portion of the photolytic layer 7. Subsequently, by removing the transfer member 8, a portion of the LED chips 11 can be transferred to the driver backplane 9.

[0076] The voltage difference between the first electrode layer 3 and the second electrode layer 4 is then set to 2V. This causes the liquid crystal 6 corresponding to the threshold voltage of 2V to transition to a light-transmitting state, and the photolytic layer 7 corresponding to the position of the liquid crystal 6 with a threshold voltage of 2V decomposes, releasing the LED chips 11 corresponding to this portion of the photolytic layer 7. The transfer member 8 is then removed, allowing a portion of the LED chips 11 to be transferred to the driver backplane 9. It should be noted that although the 2V voltage at this point exceeds the threshold voltage of the liquid crystal 6 with a threshold voltage of 1V, this has no effect because the photolytic layer 7 corresponding to the liquid crystal 6 with a threshold voltage of 1V has already decomposed and the corresponding LED chips 11 have already been transferred. This continues until the voltage difference between the first electrode layer 3 and the second electrode layer 4 is set to 4V. This causes the liquid crystal 6 corresponding to the threshold voltage of 4V to transition to a light-transmitting state, and the photolytic layer 7 corresponding to the position of the liquid crystal 6 with a threshold voltage of 4V decomposes, releasing the LED chips 11 corresponding to this portion of the photolytic layer 7. The transfer member 8 is then removed, allowing the final portion of the LED chips 11 to be transferred to the driver backplane 9, completing the selective transfer of the LED chips 11.

[0077] In the above embodiment of the present invention, the voltage difference between the first electrode layer 3 and the second electrode layer 4 is increased in stages so that the voltage difference traverses the threshold voltages of the threshold voltage set in sequence from the minimum threshold voltage to the maximum threshold voltage. Each threshold voltage corresponds to the decomposition of the photoresist layer 7 connected to the LED chip 11, until all the LED chips 11 are transferred to the driving backplane 9 in batches through the transfer member 8. The threshold voltage of the liquid crystal 6 at the corresponding position can be set according to the position of the LED chip 11 to be transferred, thereby effectively completing the selective transfer of the LED chip 11 in batches.

[0078] In one embodiment, the difference between two adjacent threshold voltages in the threshold voltage set is greater than or equal to 1V.

[0079] Because the principle of this application is to make the liquid crystals 6 with different threshold voltages deflect successively under different voltage differences, thereby completing the selective batch transfer of all LED chips 11, in order to avoid the voltage difference being too close, which will lead to erroneous transfer, the threshold voltages of different liquid crystals 6 are kept as large as possible to ensure that the voltage division size is above 1V (including 1V). The phase difference here refers to the absolute value of the difference between two adjacent threshold voltages.

[0080] Referring to Figure 13 , Figure 13 is a flowchart of the selective transfer method of the third embodiment of the LED chip, the steps of S300 include S301, a first polarizer 10 is arranged on the side of the first transparent substrate 1 away from the first electrode layer 3, a second polarizer 12 is arranged on the side of the second transparent substrate 2 away from the second electrode layer 4, and the first transparent substrate 1 and the second transparent substrate 2 are assembled together to form a temporary substrate; wherein the polarization direction of the first polarizer 10 and the polarization direction of the second polarizer 12 are orthogonal; or,

[0081] Referring to Figure 14 , Figure 14 is a flowchart of the selective transfer method of the fourth embodiment of the LED chip, the steps of S300 include S302, the first transparent substrate 1 and the second transparent substrate 2 are assembled together, a first polarizer 10 is arranged on the side of the first transparent substrate 1 away from the first electrode layer 3, and a second polarizer 12 is arranged on the side of the second transparent substrate 2 away from the second electrode layer 4 to form a temporary substrate; wherein the polarization direction of the first polarizer 10 and the polarization direction of the second polarizer 12 are orthogonal.

[0082] The first polarizer 10 and the second polarizer 12 can be arranged on the first transparent substrate 1 and the second transparent substrate 2 respectively before the first transparent substrate 1 and the second transparent substrate 2 are assembled together, or the first polarizer 10 and the second polarizer 12 can be arranged after the first transparent substrate 1 and the second transparent substrate 2 are assembled together. The first polarizer 10 and the second polarizer 12 are used for allowing light of a specific polarization direction to pass through, and the polarization direction of the first polarized light is opposite to the polarization direction of the second polarized light. In the absence of the liquid crystal 6, as shown in FIG. 6, there is a gap H between the liquid crystals 6, and if the laser passes through the gap of the temporary substrate, it may cause the decomposition of the photodegradable adhesive layer 7. By arranging the first polarizer 10 and the second polarizer 12, the laser passing through the first polarizer 10 cannot pass through the second polarizer 12. In this way, the laser can be prevented from directly emitting to the photodegradable adhesive layer 7 from the gap of the liquid crystal 6, so that the decomposition of the photodegradable adhesive layer 7 caused by the transfer deviation is avoided. Figure 10

[0083] At the same time, when the pressure difference on both sides of the liquid crystal does not reach the threshold voltage, the polarization state of the light passing through the first polarizer 10 will not change after passing through the liquid crystal 6, and the light cannot pass through the second polarizer 12, so that the laser light cannot be emitted onto the photodegradable adhesive layer 7.

[0084] ​In addition, for the laser light irradiated on the liquid crystal 6, the liquid crystal 6 that reaches the threshold voltage and changes to the transparent state will cause the polarization state of the light passing through the liquid crystal 6 to change, for example, the linearly polarized light passing through the first polarizer 10 can be converted into elliptically polarized light or circularly polarized light, so that at least a part of the laser light after the conversion through the liquid crystal 6 can pass through the second polarizer 12 and be incident on the photolytic layer 7.

[0085] In the above embodiment of the present invention, by providing the first polarizer 10 and the second polarizer 12, it is possible to prevent the laser light that has not passed through the liquid crystal 6 from directly passing through the transient substrate and incident on the photolytic layer 7 to decompose the photolytic layer 7 and release the corresponding LED chip 11, thereby ensuring the orderly selective transfer of the LED chip 11.

[0086] In one embodiment, the step of coating the photoresist layer 7 on one side of the temporary substrate includes:

[0087] A photolytic adhesive layer 7 is coated on the side of the first polarizer 10 facing away from the first transparent substrate 1;

[0088] The step of coating a photoresist layer 7 on one side of the transient substrate comprises:

[0089] The step of using laser to irradiate the temporary substrate from the side of the temporary substrate facing away from the photoresist layer 7 includes:

[0090] The laser is emitted toward the second polarizer 12 from the side of the second polarizer 12 facing away from the second transparent substrate 2 .

[0091] In another embodiment, the step of coating the photoresist layer 7 on one side of the temporary substrate includes:

[0092] A photolytic adhesive layer 7 is coated on the side of the second polarizer 12 facing away from the second transparent substrate 2;

[0093] The step of coating a photoresist layer 7 on one side of the transient substrate comprises:

[0094] The step of using laser to irradiate the temporary substrate from the side of the temporary substrate facing away from the photoresist layer 7 includes:

[0095] The laser is emitted toward the first polarizer 10 from the side of the first polarizer 10 facing away from the first transparent substrate 1 .

[0096] The photosolvent layer 7 can be coated on the first polarizer 10 or the second polarizer 12. If coated on the first polarizer 10, the laser light is emitted from the side of the second polarizer 12 facing away from the second transparent substrate 2 toward the second polarizer 12, then passes through the second transparent substrate 2 toward the liquid crystal 6. If the liquid crystal 6 is in a light-transmitting state, the laser light passes through the liquid crystal 6 and then through the first transparent substrate 1 and the first polarizer 10 toward the photosolvent layer 7. If coated on the second polarizer 12, the laser light is emitted from the side of the first polarizer 10 facing away from the first transparent substrate 1 toward the first polarizer 10, then passes through the first transparent substrate 1 toward the liquid crystal 6. If the liquid crystal 6 is in a light-transmitting state, the laser light passes through the liquid crystal 6 and then through the second transparent substrate 2 and the second polarizer 12 toward the photosolvent layer 7.

[0097] In the above embodiment of the present invention, the laser is incident from the side of the polarizer without the photolytic layer 7, so that the laser can only be incident on the photolytic layer 7 through the transparent liquid crystal 6, which is conducive to the batch transfer of LED chips 11.

[0098] In one embodiment, before the step of adding liquid crystals 6 with different threshold voltages into each receiving groove 14, the following steps are further included:

[0099] An alignment film is disposed in the receiving groove 14 .

[0100] The alignment film mainly plays an alignment role, giving the liquid crystal 6 an initial deflection state, so that the liquid crystal 6 is in an opaque state in the initial state. Only when the applied voltage difference is greater than the threshold voltage of the liquid crystal 6 will the liquid crystal 6 change to a transparent state.

[0101] Reference Figure 15 , Figure 15 FIG5 is a flow chart of a method for selectively transferring LED chips according to a fifth embodiment of the present invention. Step S500 includes:

[0102] S501, provide a transfer substrate 81, set an adhesive layer 82 on one side of the transfer substrate 81 to form a transfer part 8, and bond the adhesive layer 82 to the LED chip 11; wherein, the adhesion between the adhesive layer 82 and the LED chip 11 is smaller than the adhesion between the photolytic adhesive layer 7 and the LED chip 11.

[0103] Combined with reference Figure 10 and Figure 11The adhesive layer 82 adheres the LED chip 11 by the adhesive effect of the adhesive, but since the adhesive force between the adhesive layer 82 and the LED chip 11 is less than the adhesive force between the photodegradable adhesive layer 7 and the LED chip 11, the LED chip 11 remains on the photodegradable adhesive layer 7 when the photodegradable adhesive layer 7 is not decomposed, and the transfer substrate 81 can only transfer the LED chip 11 corresponding to the position where the photodegradable adhesive layer 7 has been decomposed, that is, the transfer substrate 81 can only transfer the LED chip 11 that has been released. In this way, the LED chip 11 at the position corresponding to the liquid crystal 6 that has not been converted to a light-transmitting state will not be transferred, so that the selective transfer of the LED chip 11 is realized by gradually increasing the pressure difference between the first electrode layer 3 and the second electrode layer 4. The adhesive layer 82 can be made of a weakly adhesive material such as PDMS (Polydimethylsil, polydimethylsiloxane).

[0104] In the above embodiment of the present application, the adhesive layer 82 is arranged on one side of the transfer substrate 81 to adhere the LED chip 11, and the adhesive force between the adhesive layer 82 and the LED chip 11 is less than the adhesive force between the photodegradable adhesive layer 7 and the LED chip 11, so that the selective transfer of the LED chip 11 is realized by gradually increasing the pressure difference between the first electrode layer 3 and the second electrode layer 4.

[0105] According to another aspect of the present application, the present application also provides a light-emitting substrate, which comprises a driving backplate 9 and a plurality of LED chips 11 arranged on one side of the driving backplate 9, and the LED chips 11 are transferred by the above-mentioned selective transfer method of LED chips. Since the light-emitting substrate is made by the above-mentioned selective transfer method of LED chips, it at least has all the beneficial effects of the above-mentioned selective transfer method of LED chips, which will not be repeated here.

[0106] According to another aspect of the present application, the present application also provides a display panel, which comprises a housing and the above-mentioned light-emitting substrate. Since the display panel comprises all the technical solutions of the above-mentioned light-emitting substrate, it at least has all the beneficial effects of the above-mentioned technical solutions, which will not be repeated here.

[0107] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and do not limit the patent scope of the present invention. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that under the technical concept of the present invention, the technical solutions described in the aforementioned embodiments can still be modified, or some or all of the technical features therein can be replaced by equivalents; or directly / indirectly applied to other related technical fields, and these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and description of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A method for selectively transferring LED chips, characterized in that: The selective transfer method of the LED chip comprises the following steps: Providing a first transparent substrate, disposing a plurality of first electrode layers on the first transparent substrate; disposing a retaining wall on each of the first electrode layers, each retaining wall forming a receiving groove with the first transparent substrate; Adding liquid crystals with different threshold voltages into each of the holding tanks; wherein each holding tank is filled with liquid crystals with one threshold voltage; Providing a second transparent substrate, and disposing a second electrode layer on the second transparent substrate; assembling the first transparent substrate and the second transparent substrate face to face to form a transient substrate; wherein the first electrode layer is disposed facing the second electrode layer; Coating a photolytic adhesive layer on one side of the temporary substrate, bonding an LED chip to the photolytic adhesive layer so that the LED chip is disposed corresponding to the first electrode layer; Providing a transfer member connected to the LED chip; A laser is used to irradiate the transient substrate from the side of the transient substrate away from the photolytic glue layer; and the first electrode layer and the second electrode layer are energized; a plurality of different threshold voltages are arranged in sequence from small to large to form a threshold voltage set, and the threshold voltage set includes a minimum threshold voltage with the smallest threshold voltage and a maximum threshold voltage with the largest threshold voltage; the voltage difference between the first electrode layer and the second electrode layer is increased in stages, so that the voltage difference traverses the threshold voltages of the threshold voltage set in sequence from the minimum threshold voltage to the maximum threshold voltage, and each threshold voltage corresponds to the decomposition of the photolytic glue layer connected to the LED chip, until all the LED chips are transferred to the driving backplane in batches through the transfer member.

2. The selective transfer method of LED chips according to claim 1, characterized in that: The difference between two adjacent threshold voltages in the threshold voltage set is greater than or equal to 1V.

3. The selective transfer method of LED chips according to claim 1 or 2, characterized in that: The step of assembling the first transparent substrate and the second transparent substrate facing each other to form a transient substrate comprises: A first polarizer is disposed on a side of the first transparent substrate facing away from the first electrode layer, and a second polarizer is disposed on a side of the second transparent substrate facing away from the second electrode layer, and the first transparent substrate and the second transparent substrate are assembled together facing each other to form a transient substrate; wherein the polarization direction of the first polarizer is orthogonal to the polarization direction of the second polarizer; or The first transparent substrate and the second transparent substrate are assembled together facing each other, a first polarizer is arranged on the side of the first transparent substrate facing away from the first electrode layer, and a second polarizer is arranged on the side of the second transparent substrate facing away from the second electrode layer to form a transient substrate; wherein the polarization direction of the first polarizer is orthogonal to the polarization direction of the second polarizer.

4. The method for selectively transferring LED chips according to claim 3, wherein: The step of coating a photolytic adhesive layer on one side of the transient substrate comprises: Coating a photolytic adhesive layer on a side of the first polarizer facing away from the first transparent substrate; The step of using laser light to irradiate the transient substrate from the side of the transient substrate facing away from the photolytic adhesive layer comprises: Laser is used to irradiate the second polarizer from a side of the second polarizer away from the second transparent substrate.

5. The selective transfer method of LED chips according to claim 3, characterized in that: The step of coating a photolytic adhesive layer on one side of the transient substrate comprises: Coating a photolytic adhesive layer on a side of the second polarizer facing away from the second transparent substrate; The step of using laser light to irradiate the transient substrate from the side of the transient substrate facing away from the photolytic adhesive layer comprises: Laser is used to irradiate the first polarizer from a side of the first polarizer away from the first transparent substrate.

6. The selective transfer method of LED chips according to claim 1 or 2, characterized in that: Before the step of adding liquid crystals with different threshold voltages into each of the receiving grooves, the method further includes the following steps: An alignment film is disposed in the receiving groove.

7. The method for selectively transferring LED chips according to claim 1 or 2, wherein: The step of providing a transfer member connected to the LED chip includes: A transfer substrate is provided, and an adhesive layer is set on one side of the transfer substrate to form a transfer piece, and the adhesive layer is bonded to the LED chip; wherein the adhesion between the adhesive layer and the LED chip is smaller than the adhesion between the photolytic adhesive layer and the LED chip.

8. A light-emitting substrate, characterized in that: The light-emitting substrate includes a driving backplane and a plurality of LED chips arranged on one side of the driving backplane, and the LED chips are transferred by the selective transfer method of LED chips according to any one of claims 1 to 7.

9. A display panel, characterized in that: The display panel includes a housing and the light-emitting substrate according to claim 8 .

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