A transfer substrate and a preparation method of a display panel

Abstract

The application discloses a transfer substrate and a preparation method of a display panel. The transfer substrate comprises a bearing substrate, a bonding adhesive layer and a light emitting element group. The bonding adhesive layer comprises a first bonding adhesive layer and a second bonding adhesive layer arranged on opposite sides of the bearing substrate. The light emitting element group comprises a plurality of first light emitting element groups on the side of the first bonding adhesive layer away from the bearing substrate and a plurality of second light emitting element groups on the side of the second bonding adhesive layer away from the bearing substrate. The first light emitting element group comprises at least one first light emitting element, and the second light emitting element group comprises at least one second light emitting element. By arranging the first bonding adhesive layer and the second bonding adhesive layer on the two sides of the bearing substrate, the light emitting element group is arranged on the two sides of the bonding adhesive layer away from the bearing substrate. Thus, the transfer substrate can be flipped to realize twice bonding during bonding, and the bonding efficiency is high.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of light emitting, in particular to a transfer substrate and a preparation method of a display panel. BACKGROUND

[0002] At present, laser mass bonding is one of the main bonding methods of Micro Light Emitting Diode Display (Micro LED), and the basic process is to align and press the temporary substrate with arranged Micro LED chips to the corresponding position of the substrate, and then heat the bonding layer between the substrate pad and the LED pad through laser irradiation to electrically connect the Micro LED and the substrate.

[0003] At present, in the Micro LED laser bonding process, the chip is pasted on the carrier (Chip On Carrier, COC), that is, the laser bonding glue is arranged on one side of the carrier, and the Micro LED chip is placed on the laser bonding glue. The COC structure can only be bonded once each time, and the utilization rate of the carrier is low and the bonding efficiency is low. SUMMARY

[0004] Embodiments of the present application provide a transfer substrate and a preparation method of a display panel to improve the bonding efficiency.

[0005] In a first aspect, embodiments of the present application provide a transfer substrate, comprising: a carrier substrate, a bonding adhesion layer, and a light emitting element group.

[0006] The bonding adhesion layer comprises a first bonding adhesion layer and a second bonding adhesion layer arranged on opposite sides of the carrier substrate.

[0007] The light emitting element group comprises a plurality of first light emitting element groups on the side of the first bonding adhesion layer away from the carrier substrate and a plurality of second light emitting element groups on the side of the second bonding adhesion layer away from the carrier substrate. The first light emitting element group comprises at least one first light emitting element, and the second light emitting element group comprises at least one second light emitting element.

[0008] In a second aspect, embodiments of the present application also provide a preparation method of a display panel, comprising:

[0009] The application provides a transfer substrate; the transfer substrate comprises a bearing substrate, a bonding adhesive layer and a light emitting element group; the bonding adhesive layer comprises a first bonding adhesive layer and a second bonding adhesive layer which are oppositely arranged on two sides of the bearing substrate; the light emitting element group comprises a plurality of first light emitting element groups which are located on a side of the first bonding adhesive layer away from the bearing substrate and a plurality of second light emitting element groups which are located on a side of the second bonding adhesive layer away from the bearing substrate; the first light emitting element group comprises at least one first light emitting element, and the second light emitting element group comprises at least one second light emitting element.

[0010] The first driving substrate is provided, and the first light emitting element group is transferred to the first driving substrate.

[0011] The second driving substrate is provided, and the transfer substrate is turned over, and the second light emitting element group is transferred to the second driving substrate.

[0012] The technical scheme provided by the embodiment of the application is that the first bonding adhesive layer and the second bonding adhesive layer are arranged on two sides of the bearing substrate, the first light emitting element group is located on a side of the first bonding adhesive layer away from the first bearing substrate, and the second light emitting element group is located on a side of the second bonding adhesive layer away from the second bearing substrate, so that the first light emitting element group can be bonded to the driving substrate first when bonding, and the second light emitting element group can be bonded to the driving substrate through turning over of the transfer substrate, which can improve the utilization rate of the bearing substrate and improve the bonding efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 The structure schematic diagram of the first transfer substrate provided by the embodiment of the application is shown in the figure.

[0014] Figure 2 The top view schematic diagram of the first transfer substrate provided by the embodiment of the application is shown in the figure.

[0015] Figure 3 The top view schematic diagram of the second transfer substrate provided by the embodiment of the application is shown in the figure.

[0016] Figure 4 The structure schematic diagram of the second transfer substrate provided by the embodiment of the application is shown in the figure.

[0017] Figure 5 The structure schematic diagram of the third transfer substrate provided by the embodiment of the application is shown in the figure.

[0018] Figure 6 The structure schematic diagram of the fourth transfer substrate provided by the embodiment of the application is shown in the figure.

[0019] Figure 7 The preparation process flow chart of the first display panel provided by the embodiment of the application is shown in the figure.

[0020] Figure 8 A process flow diagram for the fabrication of a second type of display panel provided in an embodiment of the present invention. Detailed Implementation

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0022] The inventors discovered that in the existing display panel manufacturing process, the light-emitting element is located on one side of the carrier substrate. Each carrier substrate can only be bonded once. The carrier substrate that has been bonded once is scrapped or recycled, which is costly and has low utilization rate.

[0023] Based on the above research findings, the inventors further developed the technical solution in the embodiments of the present invention. By providing a first bonding and adhesion layer and a second bonding and adhesion layer on both sides of the carrier substrate, the first light-emitting element group is located on the side of the first bonding and adhesion layer away from the first carrier substrate, and the second light-emitting element group is located on the side of the second bonding and adhesion layer away from the second carrier substrate. In this way, during bonding, the first light-emitting element group can be bonded to the driving substrate first, and the second light-emitting element group can be bonded to the driving substrate by flipping the transfer substrate. This can improve the utilization rate of the carrier substrate and the bonding efficiency.

[0024] The above is the core idea of ​​this invention. The technical solutions in the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0025] Figure 1 This is a schematic diagram of the structure of the first type of transfer substrate provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the transfer substrate includes: a carrier substrate 10, a bonding and adhesion layer 20, and a light-emitting element group 30; the bonding and adhesion layer 20 includes a first bonding and adhesion layer 201 and a second bonding and adhesion layer 202 disposed opposite to each other on both sides of the carrier substrate 10; the light-emitting element group 30 includes a plurality of first light-emitting element groups 301 located on the side of the first bonding and adhesion layer 201 away from the carrier substrate 10 and a plurality of second light-emitting element groups 302 located on the side of the second bonding and adhesion layer 202 away from the carrier substrate 10; the first light-emitting element group 301 includes at least one first light-emitting element 3011, and the second light-emitting element group 302 includes at least one second light-emitting element 3021.

[0026] Specifically, the bonding adhesive layer 20 includes a first bonding adhesive layer 201 and a second bonding adhesive layer 202 arranged on opposite sides of the carrier substrate 10, that is, the bonding adhesive layer 20 includes the first bonding adhesive layer 201 and the second bonding adhesive layer 202, the first bonding adhesive layer 201 is located on one side of the carrier substrate 10, and the second bonding adhesive layer 202 is located on the other side of the carrier substrate 10. The bonding adhesive layer 20 is used to adhere the carrier substrate 10 and the light emitting element group 30, so that the light emitting element group 30 can be arranged on both sides of the same carrier substrate 10, thereby improving the utilization rate of the carrier substrate 10.

[0027] Further, the first light emitting element group 301 is located on the side of the first bonding adhesive layer 201 away from the carrier substrate 10, and the second light emitting element group 302 is located on the side of the second bonding adhesive layer 202 away from the carrier substrate 10. When transporting the light emitting element group, the first light emitting element group 301 on one side of the carrier substrate 10 can be transported to the driving substrate first, and then the carrier substrate 10 is turned over to transport the second light emitting element group 302 on the other side of the carrier substrate 10 to the driving substrate. Thus, the same carrier substrate can realize twice bonding, and the bonding efficiency is high.

[0028] It should be noted that the driving substrate electrically connected to the first light emitting element group 301 and the driving substrate electrically connected to the second light emitting element group 302 can be the same driving substrate or different driving substrates, and the embodiments of the present application do not limit this.

[0029] It can be understood that the first light emitting element group 301 includes at least one first light emitting element 3011, that is, the first light emitting element group 301 can include a single color light emitting element, and can also include a plurality of light emitting elements of different colors. For example, the first light emitting element group 301 can include red light emitting elements, green light emitting elements and blue light emitting elements to realize color light emission of the driving substrate electrically connected to the first light emitting element group 301. The second light emitting element group 302 includes at least one second light emitting element 3021, that is, the second light emitting element group 302 can include a single color light emitting element, and can also include a plurality of light emitting elements of different colors. For example, the second light emitting element group 302 can include red light emitting elements, green light emitting elements and blue light emitting elements to realize color light emission of the driving substrate electrically connected to the second light emitting element group 302.

[0030] The transfer substrate provided by the embodiment of the present application is provided with a first bonding adhesive layer and a second bonding adhesive layer on two sides of the bearing substrate, the first light emitting element group is located on the side of the first bonding adhesive layer away from the first bearing substrate, and the second light emitting element group is located on the side of the second bonding adhesive layer away from the second bearing substrate, so that the first light emitting element group can be bonded to the driving substrate first, and then the second light emitting element group can be bonded to the driving substrate by turning over the transfer substrate, which can improve the utilization rate of the bearing substrate and the bonding efficiency.

[0031] Optionally, continuing to refer to Figure 1 The bonding adhesive layer 20 comprises laser bonding glue, so that the bearing substrate 10 and the light emitting element group 30 can be adhered by the laser bonding glue, and the laser bonding glue has high transmittance to the bonding laser, so that the laser bonding glue does not hinder the laser from being incident on the light emitting element during bonding, thereby ensuring the normal bonding connection between the light emitting element and the driving substrate.

[0032] Optionally, continuing to refer to Figure 1 The transmittance N1 of the first bonding adhesive layer 201 to the bonding laser satisfies N1>=98%, and the transmittance N2 of the second bonding adhesive layer 202 to the bonding laser satisfies N2>=98%.

[0033] Specifically, the wavelength of the bonding laser can be 980nm-1064nm, and the transmittance of the first bonding adhesive layer 201 and the second bonding adhesive layer 202 to the bonding laser is as high as 98% or more, so that the bonding laser can be transmitted through the bonding adhesive layer 20 to heat and bond the electrodes of the light emitting element and the bonding structure in the driving substrate.

[0034] Optionally, continuing to refer to Figure 1 The first light emitting element 3011 comprises a first electrode 31 and a first epitaxial structure 32, and the first electrode 31 is located on the side of the first epitaxial structure 32 away from the first bonding adhesive layer 201. The second light emitting element 3021 comprises a second electrode 33 and a second epitaxial structure 34, and the second electrode 33 is located on the side of the second epitaxial structure 34 away from the second bonding adhesive layer 202.

[0035] Specifically, the first light emitting element 3011 comprises a first electrode 31 and a first epitaxial structure 32 connected by wires, the first electrode 31 can comprise a first anode and a first cathode, and the first epitaxial structure 32 can comprise a first P-type semiconductor layer, a first quantum well layer and a first N-type semiconductor layer. The first electrode 31 is located on the side of the first epitaxial structure 32 away from the first bonding adhesive layer 201, so that the first electrode 31 can be placed on the bonding structure in the direction towards the driving substrate during bonding, so as to bond the first light emitting element 3011 with the bonding structure on the driving substrate.

[0036] Specifically, the second light emitting element 3021 includes the second electrode 33 and the second epitaxial structure 34 electrically connected, the second electrode 33 can include a second anode and a second cathode, and the second epitaxial structure 34 can include a second P-type semiconductor layer, a second quantum well layer and a second N-type semiconductor layer. The second electrode 33 is located on the side of the second epitaxial structure 34 away from the second bonding adhesive layer 202. When bonding, the second electrode 33 can fall on the bonding structure in the direction towards the driving substrate, so that the second light emitting element 3021 is bonded with the bonding structure on the driving substrate.

[0037] Optionally, continuing to refer to Figure 1 , along the thickness direction (such as the Z direction shown in the figure) of the transfer substrate, the gap between the first light emitting element group 301 and the two adjacent second light emitting element groups 302 overlaps.

[0038] Specifically, since the light emitting elements and the bonding structure on the driving substrate are one-to-one corresponding, the area outside the bonding structure is a line and a transparent area, and cannot be bonded. Therefore, there is a gap between the two adjacent light emitting element groups on the same side of the carrier substrate 10. The gap between the first light emitting element group 301 and the two adjacent second light emitting element groups 302 overlaps, that is, the orthographic projection of the first light emitting element group 301 on the carrier substrate 10 and the orthographic projection of the second light emitting element group 302 on the carrier substrate 10 do not overlap. Therefore, when the first light emitting element group 301 is bonded, it can be ensured that the bonding laser is transmitted to the electrode and the bonding structure of the first light emitting element group 302 through the gap between the two adjacent second light emitting element groups 302, and then the electrode and the bonding structure are heated and bonded.

[0039] Optionally, Figure 2 The first transfer substrate provided by the embodiment of the present application is shown in the top view as Figure 2 , along the first direction (such as the X direction shown in the figure), the distance p1 between the two adjacent first light emitting element groups 301 is equal to the distance p2 between the two adjacent second light emitting element groups 302; the first direction X is parallel to the plane in which the carrier substrate 10 is located and intersects the thickness direction of the transfer substrate.

[0040] Specifically, along the first direction X, the distance p1 between the two adjacent first light emitting element groups 301 can be understood as the distance between the same side edges of any two light emitting elements of the same color in the two adjacent first light emitting element groups 301, and the distance p2 between the two adjacent second light emitting element groups 302 can be understood as the distance between the same side edges of any two light emitting elements of the same color in the two adjacent second light emitting element groups 302. p1 = p2, so that the first light emitting element group 301 and the second light emitting element group 302 can be bonded to the same type of driving substrate, that is, the first light emitting element group 301 and the second light emitting element group 302 can be respectively bonded to the same type of driving substrate, thereby improving the bonding efficiency.

[0041] Optionally, Figure 3 A second top view schematic diagram of the transfer substrate provided by the embodiment of the present application is shown in FIG. 4. Figure 3 As shown in FIG. 4, along the first direction X, the distance between the two adjacent first light emitting element groups 301 is different from the distance between the two adjacent second light emitting element groups 302; the first direction X is parallel to the plane where the carrier substrate 10 is located and intersects the thickness direction of the transfer substrate.

[0042] Specifically, along the first direction X, the distance p1 between the two adjacent first light emitting element groups 301 is different from the distance p2 between the two adjacent second light emitting element groups 302, so that the first light emitting element group 301 can be bonded to the first type of driving substrate, and the second light emitting element group 302 can be bonded to the second type of driving substrate, that is, the light emitting elements can be bonded to two different types of driving substrates to adapt to different specifications of the driving substrates.

[0043] Optionally, Figure 4 A second structure schematic diagram of the transfer substrate provided by the embodiment of the present application is shown in FIG. 5. Figure 4 As shown in FIG. 5, the first bonding and adhering layer 201 includes a plurality of first bonding and adhering subparts 2011 and a plurality of second bonding and adhering subparts 2012; along the thickness direction Z of the transfer substrate, the first bonding and adhering subparts 2011 cover the first light emitting element groups 301; the second bonding and adhering subparts 2012 cover the second light emitting element groups 302; in a unit volume, the volume of the bonding and adhering material in the second bonding and adhering subparts 2012 is less than the volume of the bonding and adhering material in the first bonding and adhering subparts 2011; the second bonding and adhering layer 202 includes a plurality of third bonding and adhering subparts 2021 and a plurality of fourth bonding and adhering subparts 2022; along the thickness direction Z of the transfer substrate, the third bonding and adhering subparts 2021 cover the second light emitting element groups 302, and the fourth bonding and adhering subparts 2022 cover the first light emitting element groups 301; in a unit volume, the volume of the bonding and adhering material in the fourth bonding and adhering subparts 2022 is less than the volume of the bonding and adhering material in the third bonding and adhering subparts 2021.

[0044] Specifically, the volume of the bonding adhesive material in the second bonding adhesive sub-section 2012 is less than the volume of the bonding adhesive material in the first bonding adhesive sub-section 2011 in a unit volume, which means that the content of the bonding adhesive material in the second bonding adhesive sub-section 2012 is less than the content of the bonding adhesive material in the first bonding adhesive sub-section 2011. The volume of the bonding adhesive material in the fourth bonding adhesive sub-section 2022 is less than the volume of the bonding adhesive material in the third bonding adhesive sub-section 2021 in a unit volume, which means that the content of the bonding adhesive material in the fourth bonding adhesive sub-section 2022 is less than the content of the bonding adhesive material in the third bonding adhesive sub-section 2021. The content of the bonding adhesive material in the second bonding adhesive sub-section 2012 and the fourth bonding adhesive sub-section 2022 is less, which can ensure a higher transmittance of the bonding laser. The content of the bonding adhesive material in the first bonding adhesive sub-section 2011 and the third bonding adhesive sub-section 2021 is more, which can ensure a better adhesion effect on the light emitting element and a better buffering effect during bonding, so as not to crush the driving substrate. During the bonding of the first light emitting element group 301, the bonding laser transmits through the fourth bonding adhesive sub-section 2022 to heat and bond the electrode 31 and the bonding structure of the first light emitting element group 301. Since the content of the bonding adhesive material in the fourth bonding adhesive sub-section 2022 is less, the transmittance of the bonding laser is higher, which ensures a good bonding effect between the first light emitting element group 301 and the driving substrate. During the bonding of the second light emitting element group 302, the bonding laser transmits through the second bonding adhesive sub-section 2012 to heat and bond the electrode 33 and the bonding structure of the second light emitting element group 302. Since the content of the bonding adhesive material in the second bonding adhesive sub-section 2012 is less, the transmittance of the bonding laser is higher, which ensures a good bonding effect between the second light emitting element group 302 and the driving substrate.

[0045] Optionally, with reference to Figure 4 , the thickness of the second bonding adhesive sub-section 2012 is less than the thickness of the first bonding adhesive sub-section 2011; and the thickness of the fourth bonding adhesive sub-section 2022 is less than the thickness of the third bonding adhesive sub-section 2021.

[0046] Specifically, the thickness of the second bonding adhesive sub-section 2012 is less than the thickness of the first bonding adhesive sub-section 2011, that is, in the first bonding adhesive layer 201, the thickness of the second bonding adhesive sub-section 2012 corresponding to the gap position between the two adjacent first light emitting element groups 301 is less than the thickness of the first bonding adhesive sub-section 2011 corresponding to the first light emitting element group 301. This can ensure the adhesion effect of the first bonding adhesive sub-section 2011 on the first light emitting element group 301 and the buffering effect during bonding, and can also improve the transmittance of the second bonding adhesive sub-section 2012 to the bonding laser, thereby ensuring the bonding effect between the second light emitting element group 302 and the driving substrate.

[0047] Specifically, the thickness of the fourth bonding and adhering part 2022 is less than the thickness of the third bonding and adhering part 2021, that is, in the second bonding and adhering layer 202, the thickness of the fourth bonding and adhering part 2022 corresponding to the gap position between the two adjacent second light emitting element groups 302 is less than the thickness of the third bonding and adhering part 2021 corresponding to the second light emitting element group 302. In this way, on the one hand, the adhesion effect of the third bonding and adhering part 2021 on the second light emitting element group 302 and the buffering effect during bonding can be ensured, and on the other hand, the transmittance of the fourth bonding and adhering part 2022 to the bonding laser can be improved, thereby ensuring the bonding effect between the first light emitting element group 301 and the driving substrate.

[0048] Optionally, Figure 5 A third structure diagram of a transfer substrate provided by an embodiment of the present application is shown in FIG. 4. Figure 5 As shown in FIG. 4, at least one first groove aa is arranged in the second bonding and adhering part 2012, and the first groove aa penetrates at least part of the second bonding and adhering part 2012; at least one second groove bb is arranged in the fourth bonding and adhering part 2022, and the second groove bb penetrates at least part of the fourth bonding and adhering part 2022.

[0049] Specifically, the second bonding and adhering part 2012 is patterned to form the first groove aa, and the first groove aa penetrates at least part of the second bonding and adhering part 2012. In this way, the transmittance of the bonding laser can be further improved, which is beneficial to further ensure the bonding effect between the second light emitting element group 302 and the driving substrate.

[0050] Specifically, the fourth bonding and adhering part 2022 is patterned to form the second groove bb, and the second groove bb penetrates at least part of the fourth bonding and adhering part 2022. In this way, the transmittance of the bonding laser can be further improved, which is beneficial to further ensure the bonding effect between the first light emitting element group 301 and the driving substrate.

[0051] Optionally, Figure 6 A fourth structure diagram of a transfer substrate provided by an embodiment of the present application is shown in FIG. 5. Figure 6 As shown in FIG. 5, the thickness of the second bonding and adhering layer 202 is less than the thickness of the first bonding and adhering layer 201.

[0052] Specifically, when the first light emitting element group 301 is bonded, the bonding laser is sequentially transmitted through the second bonding adhesive layer 202, the carrier substrate 10 and the first bonding adhesive layer 201 to the electrode and the bonding structure of the first light emitting element group 301. By setting the thickness of the second bonding adhesive layer 202 to be less than the thickness of the first bonding adhesive layer 201, the thickness of the second bonding adhesive layer 202 is thinner when the first light emitting element group 301 is bonded, which can ensure that the second bonding adhesive layer 202 has a higher transmittance to the bonding laser, thereby ensuring the bonding effect.

[0053] Optionally, with reference back to Figure 1 , the thickness d1 of the first bonding adhesive layer 201 satisfies 5 μm≤d1≤30 μm; and the thickness d2 of the second bonding adhesive layer 202 satisfies 5 μm≤d2≤30 μm.

[0054] Specifically, d1 satisfies 5 μm≤d1≤30 μm, and d2 satisfies 5 μm≤d2≤30 μm, that is, the thicknesses of the first bonding adhesive layer 201 and the second bonding adhesive layer 202 are moderate, which can ensure better adhesion effect on the one hand, and better buffering effect when bonding on the other hand, thereby preventing damage to the driving substrate. In addition, it can also prevent the driving substrate and the carrier substrate from warping.

[0055] For example, when d1<5 μm and d2<5 μm, it indicates that the thicknesses of the first bonding adhesive layer 201 and the second bonding adhesive layer 202 are too thin, which can easily crush the driving substrate when bonding, and the buffering effect is not good, which can easily cause damage to the light emitting element group.

[0056] For example, when d1>30 μm and d2>30 μm, it indicates that the thicknesses of the first bonding adhesive layer 201 and the second bonding adhesive layer 202 are too thick, which has a lower transmittance to the bonding laser, thereby affecting the bonding effect.

[0057] It should be noted that, as a feasible implementation, the first bonding adhesive layer 201 and the second bonding adhesive layer 202 can both be liquid adhesive materials, such as silicone and the like. For example, the liquid adhesive material can be prepared on both sides of the carrier substrate 10 by spin coating, and the thickness of the spin coating can be controlled to about 5 μm.

[0058] As another feasible implementation, the first bonding adhesive layer 201 and the second bonding adhesive layer 202 can both be film materials. For example, the thickness of the film material is generally 20 μm.

[0059] As still another feasible implementation, the first bonding adhesive layer 201 and the second bonding adhesive layer 202 can have different forms, such as one being a liquid adhesive material and the other being a film material.

[0060] Optionally, with reference back toFigure 1 The carrying substrate 10 comprises a clamping area 101 and a laser bonding area 102; the clamping area 101 surrounds the laser bonding area 102; the bonding adhesive layer 20 covers the laser bonding area 102.

[0061] Specifically, the clamping area 101 surrounds the laser bonding area 102, and the clamping mechanism can clamp the clamping area 101 so as to fix the transfer substrate during bonding or rotate the transfer substrate after bonding, and bond the light emitting element groups to the bonding structure of the driving substrate. The bonding adhesive layer 20 covers the laser bonding area 102 and does not cover the clamping area 101, that is, the clamping area 101 is not provided with the bonding adhesive layer 20 on both sides of the carrying substrate 10. In this way, on the one hand, it can avoid leaving glue on the clamping mechanism to pollute the machine, and on the other hand, it can avoid affecting the balance of the transfer substrate due to long clamping time.

[0062] In summary, the transfer substrate provided by the embodiment of the present application is provided with a first bonding adhesive layer and a second bonding adhesive layer on both sides of the carrying substrate, the first light emitting element group is located on the side of the first bonding adhesive layer away from the first carrying substrate, and the second light emitting element group is located on the side of the second bonding adhesive layer away from the second carrying substrate. In this way, during bonding, the first light emitting element group can be bonded to the driving substrate first, and by turning over the transfer substrate, the second light emitting element group can be bonded to the driving substrate. On the one hand, it can improve the utilization rate of the carrying substrate, and on the other hand, it can improve the bonding efficiency. In addition, by patterning the bonding adhesive layer, the transmittance of the bonding laser can be improved, thereby improving the bonding efficiency.

[0063] Based on the same inventive concept, the embodiment of the present application also provides a preparation method of a display panel, Figure 7 The preparation process flow chart of the first display panel provided by the embodiment of the present application is shown in Figure 7 The preparation method of the display panel comprises the following steps:

[0064] S101, providing a transfer substrate.

[0065] The transfer substrate comprises a carrying substrate 10, a bonding adhesive layer 20 and a light emitting element group 30; the bonding adhesive layer 20 comprises a first bonding adhesive layer 201 and a second bonding adhesive layer 202 arranged opposite to each other on both sides of the carrying substrate 10; the light emitting element group 30 comprises a plurality of first light emitting element groups 301 located on the side of the first bonding adhesive layer 201 away from the carrying substrate 10 and a plurality of second light emitting element groups 302 located on the side of the second bonding adhesive layer 202 away from the carrying substrate 10; the first light emitting element group 301 comprises at least one first light emitting element 3011, and the second light emitting element group 302 comprises at least one second light emitting element 3021.

[0066] Specifically, the bonding adhesive layer 20 includes a first bonding adhesive layer 201 and a second bonding adhesive layer 202 arranged on opposite sides of the carrier substrate 10, that is, the bonding adhesive layer 20 includes the first bonding adhesive layer 201 and the second bonding adhesive layer 202, the first bonding adhesive layer 201 is located on one side of the carrier substrate 10, and the second bonding adhesive layer 202 is located on the other side of the carrier substrate 10. The bonding adhesive layer 20 is used to adhere the carrier substrate 10 and the light emitting element group 30, so that the light emitting element group 30 can be arranged on both sides of the same carrier substrate 10, thereby improving the utilization rate of the carrier substrate 10.

[0067] S102, providing a first driving substrate 40, and transferring the first light emitting element group 301 to the first driving substrate 40.

[0068] The first driving substrate 40 includes a substrate and a driving structure between the substrate and the light emitting element on one side of the substrate. The driving structure can include a plurality of pixel circuits 400 arranged in an array. The pixel circuit 400 is used to receive a scan signal and turn on or off under the action of the scan signal to provide a light emitting signal provided by a light emitting signal line to the light emitting element or stop providing the light emitting signal to the light emitting element. The light emitting signal line can include a data signal line and a positive power signal line, and the corresponding light emitting signal can include a data signal and a positive power signal. The pixel circuit 400 can include one or more thin film transistors. Taking the case where the pixel circuit 400 includes one thin film transistor as an example, the pixel circuit 400 can include at least two thin film transistors and at least one storage capacitor. For example, the pixel circuit 400 can be a “2T1C” structure pixel circuit or a “7T1C” structure pixel circuit. Here, “T” represents a thin film transistor, and “C” represents a storage capacitor. The specific composition of the pixel circuit 400 is not limited in the embodiment of the present application and can be limited according to the needs and the type of the display panel. Further, the thin film transistor can include a source electrode 401, a drain electrode 402, a gate electrode 403, and an active layer 404. The gate electrode 403 is arranged corresponding to the channel region of the active layer 404, the source electrode 401 is arranged corresponding to the source region of the active layer 404, and the drain electrode 402 is arranged corresponding to the drain region of the active layer 404. Under the action of the gate signal, the channel region is turned on and changes from a non-conductor state to a conductor state, and a path is formed between the corresponding source electrode 401 and the drain electrode 402. The data signal can be written into the drain electrode 402 through the source electrode 401 and the channel region in sequence.

[0069] Further, the electrode 31 of the first light emitting element 3011 and the bonding structure 405 can be irradiated by a bonding laser to bond the first light emitting element 3011 and the bonding structure 405, thereby transferring the first light emitting element group 301 to the first driving substrate 40.

[0070] S103, provide the second driving substrate 50 and turn over the transfer substrate, and transfer the second light emitting element group 302 to the second driving substrate 50.

[0071] Specifically, the second driving substrate 50 includes a substrate and a driving structure between the substrate and the light emitting element on one side of the substrate, the driving structure can include a plurality of arrayed pixel circuits 500, the pixel circuit 500 can include one or more thin film transistors, and the pixel circuit 500 is taken as an example for description. Taking an organic light emitting display panel as an example, the pixel circuit 500 can include at least two thin film transistors and at least one storage capacitor, further, the thin film transistor can include a source electrode 501, a drain electrode 502, a gate electrode 503 and an active layer 504, the gate electrode 503 is arranged corresponding to the channel region of the active layer 504, the source electrode 501 is arranged corresponding to the source region of the active layer 504, and the drain electrode 502 is arranged corresponding to the drain region of the active layer 504, under the action of the gate signal, the channel region is turned on and changes from a non-conductor state to a conductor state, a path is formed between the corresponding source electrode 501 and the drain electrode 502, and a data signal can be written into the drain electrode 502 through the source electrode 501 and the channel region in sequence.

[0072] Further, the transfer substrate is turned over, so that the second light emitting element 3021 faces the bonding structure 505 of the second driving substrate 50, the electrode 33 of the second light emitting element 3021 and the bonding structure 505 can be irradiated by bonding laser, so as to bond the second light emitting element 3021 and the bonding structure 505, and then transfer the second light emitting element group 302 to the second driving substrate 50.

[0073] It should be noted that, continuing to refer to Figure 2 When the distance p1 between the two adjacent first light emitting element groups 301 is equal to the distance p2 between the two adjacent second light emitting element groups 302, the first driving substrate 40 and the second driving substrate 50 can be the same type of driving substrate.

[0074] The preparation method of the display panel provided by the embodiment of the application can improve the utilization rate of the carrier substrate and the bonding efficiency.

[0075] Optionally, Figure 8 The second display panel preparation process flow provided by the embodiment of the application is shown in the following figure, Figure 8On the basis of the above-mentioned embodiments, the operation of transferring the first light emitting element group to the first driving substrate and flipping the transfer substrate, and the operation of transferring the second light emitting element group to the second driving substrate are described in detail, as shown in Figure 8 The preparation method of the display panel comprises the following steps:

[0076] S201, providing a transfer substrate.

[0077] The transfer substrate comprises a bearing substrate 10, a bonding adhesive layer 20, and a light emitting element group 30; the bonding adhesive layer 20 comprises a first bonding adhesive layer 201 and a second bonding adhesive layer 202 arranged on opposite sides of the bearing substrate 10; the light emitting element group 30 comprises a plurality of first light emitting element groups 301 on the side of the first bonding adhesive layer 201 away from the bearing substrate 10 and a plurality of second light emitting element groups 302 on the side of the second bonding adhesive layer 202 away from the bearing substrate 10; the first light emitting element group 301 comprises at least one first light emitting element 3011, and the second light emitting element group 302 comprises at least one second light emitting element 3021.

[0078] S202, placing a light shielding pattern layer 60 on the side of the second bonding adhesive layer 202 away from the bearing substrate 10; the light shielding pattern layer 60 comprises a plurality of light shielding structures 601 and a plurality of hollow structures 602; along the thickness direction of the transfer substrate 10, the light shielding structure 601 covers the second light emitting element group 302; and the hollow structure 602 covers the first light emitting element group 301.

[0079] Specifically, the light shielding pattern layer 60 comprises a plurality of light shielding structures 601 and a plurality of hollow structures 602, the light shielding structure 601 covers the second light emitting element group 302, and the hollow structure 602 covers the first light emitting element group 301, that is, in the bonding process, the bonding laser can be irradiated to the first light emitting element 3011 through the hollow structure 602 to bond the first light emitting element 3011 and the 405 bonding structure, and the light shielding structure 601 is used to shield the bonding laser to prevent the bonding laser from being irradiated to the second light emitting element 3021 to affect the second bonding.

[0080] S203, irradiating the transfer substrate through the hollow structure 602 by using the bonding laser 70 to transfer the first light emitting element group 301 to the first driving substrate 40.

[0081] Specifically, the bonding laser 70 can be an infrared laser. Illustratively, the wavelength of the bonding laser can be 980nm-1064nm. The bonding laser 70 irradiates the transfer substrate through the hollow structure 602 to heat and bond the electrode 31 of the first light emitting element 3011 and the bonding structure 405, thereby being able to transfer the first light emitting element group 301 to the first driving substrate 40.

[0082] S204, flip and translate the transfer substrate to make the light shielding structure 601 cover the gap between the two adjacent second light emitting element groups 302 and the hollow structure 602 cover the second light emitting element group 302 along the thickness direction of the transfer substrate.

[0083] Specifically, the transfer substrate is flipped to make one side of the first bonding adhesive layer 201 close to the light shielding pattern layer 60, and the transfer substrate is translated to make the light shielding structure 601 cover the gap between the two adjacent second light emitting element groups 302 and the hollow structure 602 cover the second light emitting element group 302, so that the second light emitting element 3021 is bonded by the laser through the hollow structure 602 during the second bonding.

[0084] S205, the bonding laser 70 irradiates the transfer substrate through the hollow structure 602 to transfer the second light emitting element group 302 to the second driving substrate 50.

[0085] Specifically, the bonding laser 70 irradiates the transfer substrate through the hollow structure 602 to heat bond the electrode 33 and the bonding structure 505 of the second light emitting element 3021, and then the second light emitting element group 302 is transferred to the second driving substrate 50.

[0086] The preparation method of the display panel provided by the embodiment of the present application can realize twice bonding through one carrier substrate by setting the light shielding pattern layer, and the light shielding pattern layer includes the light shielding structure and the hollow structure. During the first bonding, the bonding laser heats and bonds the electrode and the bonding structure of the first light emitting element group through the hollow structure to bond the first light emitting element group to the first driving substrate. The transfer substrate is flipped and translated, and during the second bonding, the bonding laser heats and bonds the electrode and the bonding structure of the second light emitting element group through the hollow structure to bond the second light emitting element group to the second driving substrate. Therefore, the bonding efficiency is high.

[0087] Note that the above only describes the preferred embodiments of the present application and the technical principles applied. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and those skilled in the art can make various obvious changes, re-adjustments, mutual combinations and substitutions without departing from the protection scope of the present application. Therefore, although the present application has been described in more detail through the above embodiments, the present application is not limited to the above embodiments, and can include more other equivalent embodiments without departing from the concept of the present application, and the scope of the present application is determined by the scope of the appended claims.

Claims

1. A transfer substrate, characterized by, The application relates to a light-emitting device, which comprises a carrier substrate, a bonding adhesive layer and a light-emitting element group. The bonding adhesive layer comprises a first bonding adhesive layer and a second bonding adhesive layer arranged on opposite sides of the carrier substrate. The light-emitting element group comprises a plurality of first light-emitting element groups on the side of the first bonding adhesive layer away from the carrier substrate and a plurality of second light-emitting element groups on the side of the second bonding adhesive layer away from the carrier substrate; the first light-emitting element group comprises at least one first light-emitting element, and the second light-emitting element group comprises at least one second light-emitting element. In the thickness direction of the transfer substrate, the first light-emitting element group overlaps with the gap between two adjacent second light-emitting element groups. In the first direction, the distance between two adjacent first light-emitting element groups is equal to the distance between two adjacent second light-emitting element groups; the first direction is parallel to the plane of the carrier substrate and intersects the thickness direction of the transfer substrate.

2. The transfer substrate of claim 1, wherein, In the first direction, the distance between two adjacent first light-emitting element groups is different from the distance between two adjacent second light-emitting element groups; the first direction is parallel to the plane of the carrier substrate and intersects the thickness direction of the transfer substrate.

3. The transfer substrate of claim 1, wherein, The first bonding adhesive layer comprises a plurality of first bonding adhesive subparts and a plurality of second bonding adhesive subparts; in the thickness direction of the transfer substrate, the first bonding adhesive subparts cover the first light-emitting element groups, and the second bonding adhesive subparts cover the second light-emitting element groups; in unit volume, the volume of the bonding adhesive material in the second bonding adhesive subparts is smaller than the volume of the bonding adhesive material in the first bonding adhesive subparts.

4. The transfer substrate of claim 1, wherein, The second bonding adhesive layer comprises a plurality of third bonding adhesive subparts and a plurality of fourth bonding adhesive subparts; in the thickness direction of the transfer substrate, the third bonding adhesive subparts cover the second light-emitting element groups, and the fourth bonding adhesive subparts cover the first light-emitting element groups; in unit volume, the volume of the bonding adhesive material in the fourth bonding adhesive subparts is smaller than the volume of the bonding adhesive material in the third bonding adhesive subparts. The thickness of the second bonding adhesive subpart is smaller than the thickness of the first bonding adhesive subpart.

5. The transfer substrate of claim 4, wherein, The thickness of the fourth bonding adhesive subpart is smaller than the thickness of the third bonding adhesive subpart. At least one first groove is arranged in the second bonding adhesive subpart, and the first groove penetrates at least part of the second bonding adhesive subpart.

6. The transfer substrate of claim 4, wherein, At least one second groove is arranged in the fourth bonding adhesive subpart, and the second groove penetrates at least part of the fourth bonding adhesive subpart. The thickness of the second bonding adhesive layer is smaller than the thickness of the first bonding adhesive layer.

7. The transfer substrate of claim 1, wherein, The bonding adhesive layer comprises laser bonding glue.

8. The transfer substrate of claim 1, wherein, The thickness d1 of the first bonding adhesive layer satisfies 5 mu m <= d1 <= 30 mu m, and the thickness d2 of the second bonding adhesive layer satisfies 5 mu m <= d2 <= 30 mu m.

9. The transfer substrate of claim 1, wherein, The transmittance N1 of the first bonding adhesive layer to bonding laser satisfies N1 >= 98%, and the transmittance N2 of the second bonding adhesive layer to bonding laser satisfies N2 >= 98%.

10. The transfer substrate of claim 1, wherein, The carrier substrate comprises a clamping area and a laser bonding area.

11. The transfer substrate of claim 1, wherein, ​ The clamping region surrounds the laser bonding region; the bonding adhesive layer covers the laser bonding region.

12. The transfer substrate of claim 1, wherein, The first light emitting element comprises a first electrode and a first epitaxial structure; the first electrode is located on a side of the first epitaxial structure away from the first bonding adhesive layer; The second light emitting element comprises a second electrode and a second epitaxial structure; the second electrode is located on a side of the second epitaxial structure away from the second bonding adhesive layer.

13. A method for manufacturing a display panel, characterized by, Comprise: A transfer substrate is provided; the transfer substrate comprises a carrier substrate, a bonding adhesive layer, and a light emitting element group; the bonding adhesive layer comprises a first bonding adhesive layer and a second bonding adhesive layer arranged on opposite sides of the carrier substrate; the light emitting element group comprises a plurality of first light emitting element groups located on a side of the first bonding adhesive layer away from the carrier substrate and a plurality of second light emitting element groups located on a side of the second bonding adhesive layer away from the carrier substrate; the first light emitting element group comprises at least one first light emitting element, and the second light emitting element group comprises at least one second light emitting element; A first driving substrate is provided, and the first light emitting element group is transferred to the first driving substrate; A second driving substrate is provided, and the transfer substrate is flipped, and the second light emitting element group is transferred to the second driving substrate; Wherein, along the thickness direction of the transfer substrate, the gap between the first light emitting element group and the adjacent two groups of the second light emitting element group is overlapped.

14. The method of manufacturing a display panel according to claim 13, wherein, Transferring the first light emitting element group to the first driving substrate comprises: Placing a light shielding pattern layer on a side of the second bonding adhesive layer away from the carrier substrate; the light shielding pattern layer comprises a plurality of light shielding structures and a plurality of hollow structures; along the thickness direction of the transfer substrate, the light shielding structure covers the second light emitting element group; the hollow structure covers the first light emitting element group; Using a bonding laser to irradiate the transfer substrate through the hollow structure so that the first light emitting element group is transferred to the first driving substrate; Flipping the transfer substrate to transfer the second light emitting element group to the second driving substrate comprises: Flip and translate the transfer substrate so that along the thickness direction of the transfer substrate, the light shielding structure covers the gap between the adjacent two groups of the second light emitting element group, and the hollow structure covers the second light emitting element group; Using the bonding laser to irradiate the transfer substrate through the hollow structure so that the second light emitting element group is transferred to the second driving substrate.

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