Quantum dot display panel and preparation method thereof

Abstract

The application discloses a quantum dot display panel and a preparation method thereof. The preparation method of the quantum dot display panel comprises the following steps: providing a transfer assembly plate, wherein the transfer assembly plate comprises a transfer substrate and a limiting mesh plate, a plurality of limiting holes are arranged on the limiting mesh plate, a plurality of accommodating grooves are arranged on the transfer substrate, and the limiting holes are located opposite to at least part of the accommodating grooves; forming a light-emitting material on the transfer assembly plate, wherein the light-emitting material is formed in the accommodating grooves, and the light-emitting material comprises quantum dot material; and aligning the transfer substrate carrying the light-emitting material with a receiving substrate, and transferring the light-emitting material to the receiving substrate. Through the above method, the quantum dot display can be mass-produced in a large area and at a low cost.

Description

Technical Field

[0001] This invention relates to the field of optoelectronic display technology, and in particular to a quantum dot display panel and its fabrication method. Background Technology

[0002] Quantum dots are nanoscale semiconductors. By applying a specific electric field or light pressure to these nanoscale semiconductor materials, they emit light at a specific frequency, and the frequency of the emitted light changes with the size of the semiconductor. Compared to organic light-emitting materials, quantum dots can emit light with a near-continuous spectrum, resulting in more delicate colors, a wider color gamut, longer lifespan, and greater energy efficiency. Unlike organic light-emitting materials which are deposited into films, the fabrication of electroluminescent quantum dot display panels currently mainly uses inkjet printing. However, challenges remain in the selection of quantum dot inks and the deposition of materials, meaning that a solution for large-area AM-QLED device fabrication is still lacking. Summary of the Invention

[0003] The main technical problem solved by this invention is to provide a quantum dot display panel and its preparation method, which can realize the large-area, low-cost mass production of quantum dot displays.

[0004] To solve the above-mentioned technical problems, one technical solution adopted by the present invention is: providing a method for preparing a quantum dot display panel, the method comprising: providing a transfer assembly plate, the transfer assembly plate including a transfer substrate and a positioning mesh plate, the positioning mesh plate being provided with a plurality of positioning holes, the transfer substrate being provided with a plurality of receiving grooves, the positioning holes being aligned with at least a portion of the receiving grooves; forming a light-emitting material on the transfer assembly plate, the light-emitting material being formed in the receiving grooves, the light-emitting material including quantum dot material; aligning the transfer substrate carrying the light-emitting material with a receiving substrate, and transferring the light-emitting material onto the receiving substrate.

[0005] In one embodiment, aligning the transfer substrate carrying the luminescent material with the receiving substrate and transferring the luminescent material onto the receiving substrate includes: rolling the back side of the transfer substrate to extrude the luminescent material from the receiving groove and transfer it onto the receiving substrate, wherein the back side of the transfer substrate is the side away from the opening of the receiving groove.

[0006] In one embodiment, the transfer substrate is a flexible substrate.

[0007] In one embodiment, the luminescent material further includes a colloidal material. After aligning the transfer substrate carrying the luminescent material with the receiving substrate and transferring the luminescent material onto the receiving substrate, the process includes: subjecting the receiving substrate carrying the luminescent material to light irradiation and / or heat treatment to remove the colloidal material.

[0008] In one embodiment, forming a luminescent material on a transfer plate includes: providing a printing screen; placing the transfer plate below the printing screen with the screen facing the printing screen; coating the luminescent material onto the printing screen; and then extruding the luminescent material into a receiving groove.

[0009] In one embodiment, a plurality of black limiting blocks are provided on the receiving substrate, and the plurality of black limiting blocks define a plurality of pixel openings; when the transfer substrate carrying the light-emitting material is aligned with the receiving substrate, the opening of the receiving groove is aligned with the pixel opening.

[0010] In one embodiment, the size of the pixel opening is larger than the size of the receiving slot opening.

[0011] In one embodiment, providing a transfer assembly includes: providing a transfer substrate and a positioning mesh plate respectively; aligning the positioning mesh plate with the transfer substrate such that the positioning hole is aligned with at least a portion of the receiving groove.

[0012] In one embodiment, the size of the limiting hole is smaller than the opening size of the receiving groove.

[0013] In one embodiment, the rigidity of the limiting mesh plate is greater than the rigidity of the transfer substrate.

[0014] In one embodiment, a plurality of protrusions are provided on the back side of the transfer substrate, and the back side of the transfer substrate is the side away from the opening of the receiving groove.

[0015] In one embodiment, the protrusion and the receiving groove are aligned one-to-one.

[0016] In one embodiment, the thickness of the transfer substrate is 10 to 200 micrometers.

[0017] In one embodiment, the surface of the limiting mesh plate is coated with a non-polar polymer material.

[0018] In one embodiment, the nonpolar polymeric material includes polytetrafluoroethylene (PTFE).

[0019] To solve the above-mentioned technical problems, another technical solution adopted by the present invention is to provide a transfer substrate, which includes a first surface and a second surface opposite to each other. The first surface is provided with a plurality of receiving grooves, and the second surface is provided with a plurality of protrusions corresponding to one of the receiving grooves respectively. The transfer substrate is a flexible substrate.

[0020] To solve the above-mentioned technical problems, another technical solution adopted by the present invention is to provide a quantum dot display panel, which is prepared by the quantum dot display panel preparation method of any of the above-mentioned methods.

[0021] In one embodiment, the quantum dot display panel has a PPI greater than 1000.

[0022] The beneficial effects of the present invention are as follows: Unlike the prior art, the present invention utilizes a transfer assembly plate to first form a light-emitting material containing quantum dot material on the transfer assembly plate, and then transfers it to the receiving substrate through the transfer assembly plate. By using transfer or transfer printing to form a quantum dot light-emitting structure on the receiving substrate, a large-area, high PPI display panel can be produced. Attached Figure Description

[0023] Figure 1 This is a schematic flowchart of the quantum dot display panel fabrication method in the embodiments of this application;

[0024] Figure 2 This is a schematic diagram of the transfer assembly plate in the embodiment of this application;

[0025] Figure 3 This is a schematic diagram of the planar structure of the limiting mesh plate in the embodiment of this application;

[0026] Figure 4 This is a cross-sectional structural schematic diagram of a transfer substrate in an embodiment of this application;

[0027] Figure 5 This is a cross-sectional structural schematic diagram of another transfer substrate in the embodiments of this application;

[0028] Figure 6 This is a schematic flowchart of the display panel manufacturing method in the embodiments of this application. Detailed Implementation

[0029] To make the purpose, technical solution and effects of this application clearer and more explicit, the following describes this application in further detail with reference to the accompanying drawings and embodiments.

[0030] Please refer to the following: Figure 1 , Figure 1 This is a schematic flowchart of a quantum dot display panel fabrication method according to an embodiment of this application. In this embodiment, the quantum dot display panel fabrication method includes:

[0031] S110: Provides transfer board.

[0032] The transfer assembly includes a transfer substrate and a limiting mesh plate. The limiting mesh plate is provided with multiple limiting holes, and the transfer substrate is provided with multiple receiving grooves. The limiting holes correspond to at least a portion of the receiving grooves.

[0033] S120: A light-emitting material is formed on the transfer assembly plate, and the light-emitting material is formed in the receiving groove.

[0034] Among them, luminescent materials include quantum dot materials.

[0035] S130: Align the transfer substrate carrying the luminescent material with the receiving substrate, and transfer the luminescent material onto the receiving substrate.

[0036] In this embodiment, by using a transfer assembly, a light-emitting material containing quantum dot material is first formed on the transfer assembly, and then the light-emitting material is transferred to the receiving substrate through the transfer assembly. By using a transfer or transfer printing method, a quantum dot light-emitting structure is formed on the receiving substrate, which can produce a large-area, high PPI (Pixels Per Inch) display panel.

[0037] Please refer to the following: Figure 2-4 , Figure 2 This is a schematic diagram of the transfer assembly plate in the embodiment of this application. Figure 3 This is a schematic diagram of the planar structure of the limiting mesh plate in the embodiment of this application. Figure 4 This is a cross-sectional structural diagram of a transfer substrate according to an embodiment of this application. In this embodiment, a transfer assembly plate is provided, which can be used to transfer luminescent materials. The transfer assembly plate 10 includes a transfer substrate 11 and a limiting mesh plate 12.

[0038] The limiting mesh plate 12 is provided with multiple limiting holes 121. For example... Figure 2 As shown, multiple limiting holes 121 can be arranged in an array, and the spacing between the multiple limiting holes 121 can be the same or different. The arrangement density of the limiting holes 121 in different regions of the limiting mesh plate 12 can be different, so that display panels with different PPIs in different regions can be prepared using the same limiting mesh plate 12. In this application, the specific shape of the limiting holes 121 is not limited, such as circular limiting holes, rectangular limiting holes, elliptical limiting holes, etc.; at the same time, the size of the limiting holes 121 is not limited, and can be adapted to the PPI of the target display panel. The limiting mesh plate 12 can be made of materials such as glass, metal, and polymer, so that the limiting mesh plate 12 has a certain rigidity and can play a supporting and buffering role. The limiting mesh plate 12 has a similar function to a mask plate, which can achieve selective coating of light-emitting materials.

[0039] The transfer substrate 11 has multiple receiving grooves 111 for accommodating luminescent materials. Figure 4 As shown, the receiving groove 111 is a groove with an open top and a closed bottom, forming a receiving space. The thickness of the transfer substrate 11 can be 10 to 200 μm, and the depth of the receiving groove 111 can be one-third to two-thirds of the thickness of the transfer substrate 11.

[0040] In one embodiment, the transfer substrate 11 is a flexible substrate capable of being deformed by compression. When used for transferring luminescent material, the luminescent material can be first formed in the receiving groove 111, and then, when it is necessary to transfer the luminescent material out, the transfer substrate 11 is rolled / compressed to squeeze the luminescent material out of the receiving groove 111, thereby transferring it onto the receiving substrate.

[0041] Please see Figure 5 , Figure 5 This is a cross-sectional structural diagram of another transfer substrate according to an embodiment of this application. In this embodiment, the transfer substrate 11 includes a first surface A and a second surface B opposite to each other. A receiving groove 111 is provided on the first surface A, and a protrusion 112 corresponding to a receiving groove 111 is provided on the second surface B. By providing the protrusion 112, the protrusion 112 portion can be rolled to cause a large deformation of the transfer substrate 11, extruding the light-emitting material.

[0042] In one embodiment, the protrusions 112 are aligned one-to-one with the receiving grooves 111. In this case, when the protrusions 112 are squeezed, they indent, exerting a force on the bottom of the receiving grooves 111, thereby squeezing the bottom of the receiving grooves 111 and extruding the luminescent material. In other embodiments, the shape, size, and number of the protrusions may not be the same as those of the receiving grooves.

[0043] In one embodiment, the limiting mesh plate 12 and the transfer substrate 11 are aligned and combined to form the transfer assembly plate 10, the specific structure of which is as follows: Figure 2 As shown. During assembly, the limiting hole 121 of the limiting mesh plate 12 is aligned with at least a portion of the receiving groove 111 of the transfer substrate 11. For example... Figure 2 As shown, the limiting hole 121 and the receiving groove 111 are aligned one-to-one. In this case, when the luminescent material is coated on the limiting mesh plate 12, the luminescent material can enter each receiving groove 111. In other embodiments, only some receiving grooves 111 may be aligned with the limiting hole 121, that is, some receiving grooves 111 may be blocked. In this way, selective transfer of luminescent material can be achieved. For example, for luminescent materials of different colors such as R, G, and B, they can be transferred in batches using different receiving grooves 111.

[0044] In the above embodiments, the provided transfer assembly can be used for the transfer of luminescent materials; please refer to [link / reference needed]. Figure 6 , Figure 6 This is a schematic flowchart of a display panel fabrication method according to an embodiment of this application. In this embodiment, the display panel fabrication method includes:

[0045] A transfer board 10 is provided. The transfer board 10 can be any of the transfer boards described in the above embodiments. Please refer to the above description for details, which will not be repeated here.

[0046] A luminescent material 20 is formed on the transfer plate 10.

[0047] The preparation method provided in this application can be used to prepare a quantum dot display panel, wherein the luminescent material 20 includes quantum dot material, and luminescence is achieved by using quantum dot material. The quantum dot (QD) can be CdSe / Zns quantum dot, CdSe / CdS / ZnS quantum dot, Cu-In-Se quantum dot, or PbS quantum dot, etc., and is not limited to these.

[0048] In one embodiment, the light-emitting material 20 can be formed on the transfer assembly 10 using a printing method. For details, please refer to [link to previous document]. Figure 6 The transfer assembly 10 is aligned with the printing screen 30, and the transfer assembly 10 is placed below the printing screen 30 with the limiting screen 12 facing the printing screen 30. The light-emitting material 20 is placed on the printing screen 30, and using a squeegee 40 or similar tool, the light-emitting material 20 is squeezed into the receiving groove 111 of the transfer substrate 11. Because of the presence of the limiting screen 12, the light-emitting material 20 can be squeezed into the corresponding receiving groove 111, meaning the light-emitting material 20 can be selectively coated into different receiving grooves 111, thereby selectively transferring the light-emitting material 20 to a designated pixel area.

[0049] Furthermore, the size of the limiting hole 121 is smaller than the opening size of the receiving groove 111, so that the luminescent material 20 can accurately enter the receiving groove 111 without overflowing.

[0050] Furthermore, the luminescent material 20 provided in this application includes not only quantum dot materials but also colloidal materials; that is, the luminescent material 20 is a mixture of quantum dot materials and colloidal materials. By adding colloidal materials to the luminescent material 20, it is ensured that the luminescent material 20 can adhere to the receiving groove 111 of the transfer substrate 11 by its own surface tension. Moreover, by adding colloidal materials, the mixture can be made to have a certain viscosity, facilitating coating, printing, etc.

[0051] Please continue reading. Figure 6 After the light-emitting material 20 is formed on the transfer assembly plate 10, the limiting mesh plate 12 is separated from the transfer substrate 11. The limiting mesh plate 12 can be directly removed from the transfer substrate 11 by applying external force. Care should be taken when removing it to avoid damaging the flexible transfer substrate 11.

[0052] Furthermore, a non-polar polymer material can be sprayed onto all surfaces of the limiting mesh plate 12 to prevent the colloidal material of the luminescent material from adhering. The non-polar polymer material can be polytetrafluoroethylene (also known as Teflon). Additionally, the thickness of the limiting mesh plate 12 should be as thin as possible to reduce material adhesion. After removing the limiting mesh plate 12, the transfer substrate 11 with the luminescent material 20 is aligned with the receiving substrate 50, and the luminescent material on the transfer substrate is transferred to the receiving substrate.

[0053] Please continue reading. Figure 6 A receiving substrate 50 is provided. The receiving substrate 50 can be an array substrate, such as a wearable substrate, a flexible substrate, a stretchable substrate, or a plastic substrate.

[0054] like Figure 6 As shown, the receiving substrate 50 and the transfer substrate 11 are aligned. The receiving substrate 50 has a black limiting block 51 to restrict the pixel area, i.e., the pixel opening. By setting the black limiting block 51, on the one hand, during the transfer of the light-emitting material 20, the transfer area can be restricted, ensuring that the opening of the receiving groove 111 aligns with the pixel opening. Specifically, the pixel opening size can be set larger than the receiving groove 111 opening size to ensure that the light-emitting material 20 can smoothly enter the pixel opening of the receiving substrate 50. On the other hand, by setting the black limiting block 51, large-viewing-angle color deviation can be avoided when R, G, B, and other pixels emit light.

[0055] After the receiving substrate 50 and the transfer substrate 11 are joined together, they are flipped over so that the receiving groove 111 of the transfer substrate 11 containing the light-emitting material 20 faces downwards, transferring the light-emitting material 20 onto the receiving substrate 50. Since the light-emitting material 20 has a certain viscosity, it will not flow completely and automatically onto the receiving substrate 50. A roller made of silicone rubber can be used to press the back side of the transfer substrate 11. Due to its elasticity, the transfer substrate 11 deforms, thus squeezing and transferring the light-emitting material 20 from the opposite receiving groove 111 onto the receiving substrate 50.

[0056] Furthermore, such as Figure 6 As shown, a protrusion 112 can be provided on the back side of the transfer substrate 11. By rolling the protrusion 112, the transfer substrate 11 can undergo elastic deformation, extruding the light-emitting material 20. Preferably, the protrusion 112 is correspondingly provided with the receiving groove 111 and they are matched, that is, their shape, size, and setting position are matched. In other embodiments, the protrusion 112 may not match the receiving groove 111, that is, their shapes and sizes may be different.

[0057] Please continue reading. Figure 6 After the luminescent material 20 is transferred, the transfer substrate 11 is removed, and the receiving substrate 50 is processed to remove the colloidal material contained in the luminescent material 20. The colloidal material can be a photosensitive material or a thermosensitive material. Correspondingly, the receiving substrate 50 is subjected to light irradiation or heating treatment to remove the colloidal material. The receiving substrate 50 can be irradiated with a lamp of a predetermined wavelength, such as ultraviolet or infrared lamp.

[0058] Subsequently, the display panel undergoes further packaging, cutting, and testing to be processed into a finished product.

[0059] The above embodiments utilize a transfer assembly to first form a light-emitting material containing quantum dot material on the transfer assembly, and then transfer it to a receiving substrate via the transfer assembly. By using a transfer or transfer printing method, a quantum dot light-emitting structure is formed on the receiving substrate, which can produce a large-area, high PPI (Pixels Per Inch) display panel.

[0060] Based on this, this application also provides a quantum dot display panel, which includes a quantum dot light-emitting layer, which is prepared using the preparation method of any of the above embodiments. Compared with inkjet printing, the transfer method provided in this application can achieve large-area, low-cost transfer and improve preparation accuracy, thereby increasing the PPI of the obtained quantum dot display panel.

[0061] In one embodiment, the quantum dot display panel has a PPI greater than 500, and preferably a PPI greater than 1000.

[0062] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this invention.

Claims

1. A method for fabricating a quantum dot display panel, characterized in that, The method comprises the following steps: providing a transfer assembly plate, the transfer assembly plate comprising a transfer substrate and a limiting mesh plate, the limiting mesh plate being provided with a plurality of limiting holes, the transfer substrate being provided with a plurality of accommodation grooves, the limiting holes being located opposite to at least part of the accommodation grooves, the transfer substrate being a flexible substrate, the size of the limiting holes being smaller than the opening size of the accommodation grooves, the back surface of the transfer substrate being provided with a plurality of protrusions, the back surface of the transfer substrate being the surface away from the opening of the accommodation grooves; forming a light-emitting material on the transfer assembly plate, the light-emitting material being formed in the accommodation grooves, the light-emitting material comprising quantum dot material; aligning the transfer substrate carrying the light-emitting material with a receiving substrate, and rolling the back surface of the transfer substrate to extrude the light-emitting material out of the accommodation grooves and transfer the light-emitting material to the receiving substrate.

2. The method according to claim 1, wherein the back surface of the transfer substrate is the surface away from the opening of the accommodation grooves.

3. The method according to claim 1, wherein the light-emitting material further comprises colloidal material, and after the step of aligning the transfer substrate carrying the light-emitting material with the receiving substrate and transferring the light-emitting material to the receiving substrate, the method further comprises: illuminating and / or heating the receiving substrate carrying the light-emitting material to remove the colloidal material.

4. The method according to claim 1, wherein the step of forming a light-emitting material on the transfer assembly plate comprises: providing a printing mesh plate; placing the transfer assembly plate below the printing mesh plate, and the limiting mesh plate facing the printing mesh plate; applying the light-emitting material on the printing mesh plate, and then extruding the light-emitting material into the accommodation grooves.

5. The method according to any one of claims 1-4, wherein the receiving substrate is provided with a plurality of black limiting blocks, and the black limiting blocks define a plurality of pixel openings. When aligning the transfer substrate carrying the light-emitting material with the receiving substrate, the opening of the accommodation grooves is aligned with the pixel openings.

6. The method according to claim 5, wherein the size of the pixel openings is greater than the size of the opening of the accommodation grooves. The method of providing the transfer assembly plate comprises: respectively providing the transfer substrate and the limiting mesh plate; aligning the limiting mesh plate with the transfer substrate, so that the limiting holes are located opposite to at least part of the accommodation grooves. The rigidity of the limiting mesh plate is greater than the rigidity of the transfer substrate. The protrusions are one-to-one aligned with the accommodation grooves.

7. The method of claim 1-4, wherein the method further comprises: The thickness of the transfer substrate is 10-200 microns. The surface of the limiting mesh plate is coated with a non-polar polymer material. The non-polar polymer material comprises polytetrafluoroethylene. 8.The method of claim 1, wherein the quantum dot display panel is prepared by a process comprising: forming a quantum dot layer on a substrate; and forming a color filter layer on the quantum dot layer. ​ 9. The method of claim 1-4, wherein the method further comprises: ​ 10. The method for preparing a quantum dot display panel according to any one of claims 1-4, characterized in that, ​ 11. The method of claim 1-4, wherein the method further comprises: ​ 12. The method of claim 11, wherein the method further comprises: ​

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