A quantum dot light conversion film and its manufacturing process, and a microdisplay

Abstract

This invention discloses a quantum dot light conversion film, its manufacturing process, and a microdisplay. The manufacturing process involves etching a transparent substrate to produce a high-density quantum dot light conversion film. Then, using a substrate, quantum dot luminescent material is added to the large holes (connected to small holes) through printing or other means. The material is then transferred to recesses in the transparent substrate via the small holes. The manufacturing process of this invention is not limited by the precision of quantum dot printing, but rather depends on the precision achievable by the etching process of the transparent substrate. Therefore, this invention can significantly reduce the size of quantum dot materials, improve the precision of quantum dot patterning, increase display resolution, and manufacture extremely fine and complex patterns.

Description

Technical Field

[0001] This invention relates to the field of semiconductor device manufacturing technology, and in particular to a quantum dot light conversion film for a microdisplay. Background Technology

[0002] Micro-LED displays typically use a bonding process to connect the display element (light-emitting element) to the driving element. Because the pixels of Micro-LED silicon-based microdisplays are relatively small—RBG subpixels are approximately 10µm in size, or even smaller—this places high demands on the colorization of Micro-LED silicon-based microdisplays. Currently, there are generally three approaches to colorization in Micro-LED silicon-based microdisplays:

[0003] 1. Achieving colorization through 3D nanorod technology, which can simultaneously fabricate RGB three-color LEDs on the same substrate, is still in the research stage;

[0004] 2. The RGB chips are bonded layer by layer to the silicon backplane using either flip-chip or wafer bonding. After bonding, the LED pattern is then created. This technology is quite complex and is still under research.

[0005] 3. Colorization can be achieved through quantum dot conversion. However, because the pixels of Micro-LED silicon-based microdisplays are very small, the size of a single sub-pixel is generally below 15um or even smaller. However, the current commonly used printing technology has a limit of about 30um. There are still many problems to be solved in order to achieve the size requirement of microdisplays below 10um. Therefore, it is a huge challenge to use printing technology to make quantum dot films. Summary of the Invention

[0006] To address the aforementioned technical problems, the first objective of this invention is to provide a high-precision quantum dot light conversion film.

[0007] To achieve the first objective of the invention, the present invention adopts the following technical solution: a quantum dot light conversion film, comprising a transparent substrate, wherein the transparent substrate is provided with a plurality of pits filled with quantum dot luminescent material, the plurality of pits being repeated along at least two directions, and when the pits are repeated along at least one of the directions, the distance between two adjacent pits is 0.5 to 50 μm, preferably 0.5 to 20 μm. Currently, in order to adapt to the size of mainstream Micro-LEDs, the pits of the quantum dot light conversion film are preferably 10 to 15 μm.

[0008] The second objective of this invention is to provide a novel manufacturing process for quantum dot light conversion films, which differs from previous methods in that its precision is not limited by the precision of quantum printing processes.

[0009] To achieve the second objective of the invention, the present invention adopts the following technical solution: a manufacturing process for a quantum dot light conversion film, comprising:

[0010] Step 1: Provide a substrate, form a plurality of patterned small holes on one side surface of the substrate, and open a large hole with a certain depth on the other side of the substrate. The opening area S2 of the large hole is greater than the opening area S1 of the small hole, so that the large hole is fluidly connected to N of the small holes, where N is a natural number greater than or equal to 1.

[0011] Step 2: Provide a transparent substrate, wherein the transparent substrate has a plurality of patterned recesses, and the opening area of ​​the recesses is S3;

[0012] Step 3: Align and bond the substrate with the transparent substrate so that each of the small holes corresponds to the pits;

[0013] Step 4: Add quantum dot luminescent material into the large hole, so that the quantum dot luminescent material is transferred into the pit through the small hole;

[0014] Step 7: Move the substrate and repeat steps 3 to 4 above until all the predetermined pits are filled.

[0015] The manufacturing process also includes a step of curing the quantum dot luminescent material in the pit.

[0016] In the above technical solution, preferably, there is a step 5 between step 4 and step 7, which is a step of curing the quantum dot light-emitting material; and step 6, which is to debond the substrate and the transparent substrate.

[0017] Preferably, step 3 further includes an adhesion-enhancing process between the substrate and the transparent substrate.

[0018] Preferably, in step 3, a photoresist adhesive is used to bond the substrate and the transparent substrate together.

[0019] Preferably, in step 7, when the substrate is moved, the residue on the surface of the substrate and the transparent substrate is cleaned.

[0020] Preferably, the residue is removed by pressurized gas or ultrasonic means.

[0021] In the above technical solution, optionally, in step 7, the substrate moves in any direction, first filling the substrate with quantum dot luminescent material of the same color, and then filling it with quantum dot luminescent material of different colors.

[0022] Alternatively, in step 7, the quantum dot luminescent material is moved along the direction of the same color quantum dot luminescent material. After all the same color quantum dot luminescent materials are printed, the quantum dot luminescent material is cured in one go.

[0023] Preferably, in step 4, pressure is required when the quantum dot luminescent material enters the pit through the small hole.

[0024] In the above technical solution, the substrate is further selected from silicon-based substrate, germanium substrate, sapphire substrate, and glass.

[0025] Preferably, the spacing between two adjacent holes is 0.5~100μm.

[0026] Preferably, a plurality of large holes are formed on the other side of the substrate, and each of the large holes corresponds to a set of small holes.

[0027] Preferably, the pits are formed by an etching process, and the interval between two adjacent pits is 0.5 to 100 μm.

[0028] Preferably, the number of pits on the transparent substrate is 2M or 3M times the number of holes on the substrate, where M is a natural number greater than 1.

[0029] Preferably, in step 6, the transparent substrate and the substrate are debonded by a sliding process.

[0030] Preferably, the opening shape of the recess is circular, square, hexagonal, or triangular.

[0031] Preferably, the bottom of the pit is a flat surface or an arc surface.

[0032] Preferably, S3 is greater than or equal to S1.

[0033] Preferably, in step 4, the quantum dot printing material is transferred into the macropores via a printing process or a coating process.

[0034] Preferably, the pits on the transparent substrate are divided into several groups, and each group of pits includes three pits corresponding to three different colors of quantum dot luminescent materials.

[0035] A third objective of this invention is to provide the aforementioned high-precision microdisplay.

[0036] A microdisplay includes the aforementioned quantum dot light conversion film and LED array, wherein the quantum dot light conversion film is bonded to the LED array.

[0037] Preferably, the LED array is a blue LED array or a UV-LED array.

[0038] The advantages of this invention are: the manufacturing process of the quantum dot light conversion film of this invention is not limited by the printing precision, but depends on the precision that the etching process of the transparent substrate can achieve. Therefore, this invention can greatly reduce the size of quantum dot materials, improve the quantum dot patterning precision, improve display resolution, and manufacture extremely fine and complex patterns. Attached Figure Description

[0039] Figure 1 A top view of the substrate is shown;

[0040] Figure 2 A schematic diagram of the substrate formation process is shown (along...) Figure 1 (AA section in the middle)

[0041] Figure 3 Top view of the quantum dot film to be processed;

[0042] Figure 4 Demonstrates etching pits (along) on ​​a transparent substrate Figure 3 (section along the BB direction in the middle).

[0043] Figure 5 A schematic diagram showing the alignment and bonding of the substrate and the transparent substrate is shown;

[0044] Figure 6 The experiment demonstrated how quantum dot luminescent material is filled into large holes and then enters the recesses through small holes (printing the first color of quantum dot luminescent material).

[0045] Figure 7 A top view of a substrate filled with quantum dot luminescent material is shown;

[0046] Figure 8 The paper demonstrates the ability to print a second color using quantum dot luminescent materials.

[0047] Figure 9 A schematic diagram showing the combination of quantum dot film and blue LED is presented;

[0048] Figure 10 A schematic diagram showing the combination of quantum dot films with UV-LEDs is presented;

[0049] Figure 11 A schematic diagram showing the substrate moving in any direction is presented;

[0050] Figure 12A schematic diagram showing the substrate moving along the direction of the same-color quantum dot luminescent material is shown.

[0051] Among them: 10. Substrate; 11. Small hole; 12. Large hole; 20. Quantum dot film; 21. Transparent substrate; 22. Pits; 23. Quantum dot luminescent material; 231. QDR; 232. QDG; 233. QDB; 31. Blue LED; 32. UV LED. Detailed Implementation

[0052] To explain in detail the technical content, structural features, objectives, and effects of the invention, the following will provide a detailed description in conjunction with the embodiments and accompanying drawings.

[0053] This invention discloses a quantum dot light conversion film for color displays and a method for manufacturing the quantum dot light conversion film. The quantum dot light conversion film can be used in displays such as Micro-LED, Mini-LED and OLED, and has high resolution. It can be used in high-resolution micro-displays such as AR and VR. However, this invention is not limited to the specific applications mentioned in this embodiment.

[0054] The manufacturing process of a quantum dot light conversion film according to the present invention will be described below with reference to the accompanying drawings.

[0055] The process includes:

[0056] Step 1, see Figure 1 , 2 As shown, a substrate 10 is provided, selected from silicon-based substrates, germanium substrates, sapphire substrates, glass, etc. A plurality of patterned small holes 11 are formed on one side surface of the substrate using a patterning process. Large holes 12 with a certain depth are formed on the other side of the substrate 10. The depth of the large hole is preferably sufficient to accommodate a portion of the quantum dot luminescent material. The opening area S2 of the large hole is larger than the opening area S1 of the small holes, allowing fluid communication between the large hole 12 and N of the small holes 11, where N is a natural number greater than or equal to 1. In subsequent processes, this allows quantum luminescent material to be filled into the large hole using quantum printing technology, enabling the quantum dot luminescent material within the large hole to be transferred to a quantum well through the small holes. Figure 1 This is a top view of substrate 10, showing that the large hole 12 and the small hole 11 overlap, and one large hole is connected to three small holes. Thus, the small holes in substrate 10 can be fabricated using a patterning method. Due to the mature fabrication technology, high fabrication precision can be achieved. The quantum dot luminescent material in the large holes can be fabricated using quantum printing or coating processes, reducing the difficulty of achieving high fabrication precision. When N is greater than 1, one large hole corresponds to multiple small holes, allowing multiple quantum dots to be filled in a single printing operation, resulting in higher efficiency.

[0057] Step 2, see Figure 4As shown, a transparent substrate 21 is provided, on which a plurality of patterned pits 22 are etched. Figure 3 This is a schematic diagram of the final quantum dot conversion film 20. Figure 4 yes Figure 3 Along the cross-section of BB, multiple pits 22 are closely arranged. Figure 3 shows that the pits on the transparent substrate 10 are divided into several groups, each group containing three pits corresponding to three different colors of quantum dot luminescent material. Each group of pits corresponds to one pixel of the display, and each pit corresponds to one sub-pixel of the display. The opening shape of the pit 22 can be any shape, such as circular, square, hexagonal, or triangular, while the bottom surface of the pit can be flat or curved. The depth of the three pits in each group can also be different to accommodate different volumes of quantum dot luminescent material.

[0058] Step 3, see Figure 5 As shown, the substrate 10 and the transparent substrate 21 are aligned and bonded together, so that each of the small holes 11 corresponds to the pit 22. This can be achieved using a jig, a mold, or by using a photoresist adhesive HMDS to bond the substrate and the transparent substrate. The opening area of ​​the pit 22 is S3, where S3 is greater than or equal to S1. In a preferred embodiment, to prevent the quantum dot luminescent material from being printed elsewhere, S3 is equal to S1.

[0059] Step 4, see Figure 6 Quantum dot luminescent material is added to the large aperture 12, allowing it to transfer through the small aperture 11 into the recess 22. To ensure smooth material transfer and complete filling of the recess, preferably, the quantum dot luminescent material is introduced into the recess through the small aperture under pressure, such as by using air pressure or the fluid pressure of the quantum dot luminescent material itself. Preferably, the quantum dot printing material is transferred into the large aperture via a printing or coating process.

[0060] In a typical embodiment of the present invention, the substrate and the base plate are aligned and bonded by a non-fixed method such as clamping. After step 4 is completed, step 7 is performed, in which the substrate is moved (the substrate moves along the direction of the quantum dot luminescent material of the same color), and steps 3 to 4 are repeated until all the pits that need to be filled with quantum dot luminescent material are filled. See Appendix Figure 12 After all the same-color quantum dot luminescent materials are printed, they are cured in one go. After the quantum dot luminescent material is filled, relative sliding between the substrate and the transparent substrate can be easily achieved.

[0061] In a preferred embodiment of the present invention, the substrate and the base plate undergo an adhesion enhancement process during alignment and bonding, and steps 5 and 6 are inserted between steps 4 and 7. Step 5 is to cure the quantum dot luminescent material in the pit 22, and step 6 is to debond the substrate and the transparent base plate by using a wafer sliding process to allow relative movement between the substrate 10 and the transparent base plate 21.

[0062] In this embodiment, since curing occurs after each filling of the quantum dot luminescent material, the substrate can be moved in any direction, and steps 3-6 above can be repeated until all predetermined pits are filled. See Appendix Figure 11 The substrate is moved following the principle of first filling the substrate with quantum dot luminescent material of the same color, and then filling it with quantum dot luminescent material of different colors. Before moving the substrate, any residue on the surface of the substrate and the transparent substrate is cleaned, which can be done by pressurizing gas or using ultrasound.

[0063] Since both the pinholes and pits are formed through etching, higher precision is relatively easy to achieve, and the process is relatively simple. The spacing between two adjacent pinholes can be 0.5–100 μm, and the spacing between two adjacent pits can be 0.5–100 μm. In a preferred embodiment of the invention, the minimum spacing between two adjacent pits on the transparent substrate is between 0.5 and 50 μm, particularly between 0.5 and 20 μm, depending on the photolithography precision. Currently, to accommodate the size of mainstream Micro-LEDs, the pits in the quantum dot light conversion film are preferably 10–15 μm. The number of pits on the transparent substrate is 2M or 3M times the number of pinholes on the substrate, where M is a natural number greater than 1. The number of pits in each group is related to the number of quantum dot luminescent materials in the pixels of the display. When each pixel of the display contains 3 quantum dot luminescent materials, the number of pits is 3 times the number of pinholes or an integer multiple of 3; if each pixel contains 2 quantum dot luminescent materials, the number of pits is 2 times the number of pinholes or an integer multiple of 2.

[0064] In a preferred embodiment of the present invention, a plurality of large holes are formed on the substrate 10, each large hole corresponding to a group of small holes. In other embodiments, a large hole may be formed on the substrate 10, and this large hole corresponds to all the small holes.

[0065] The microdisplay quantum dot light conversion film manufactured by the above process includes a transparent substrate 21. The transparent substrate 21 has a plurality of pits 22 filled with quantum dot luminescent material. The plurality of pits 22 are repeated along at least two directions. When the pits 22 are repeated along at least one of these directions, the distance between two adjacent pits 22 is 0.5–50 μm, preferably 0.5–20 μm. The repetition direction of the multiple pits can be along two mutually perpendicular directions to form a rectangular matrix, or it can be repeated intersecting along two directions, or three pits can be arranged in a honeycomb structure and repeated along a honeycomb arrangement.

[0066] These pits 22 are divided into multiple groups, each group of pits corresponds to one pixel of the display, and each group contains three pits corresponding to different colors of quantum dot luminescent materials.

[0067] See appendix Figure 9 , 10 As shown, a microdisplay includes an LED array and a quantum dot light conversion film 20 bonded to the LED array. The quantum dot light conversion film is fabricated using the manufacturing process of this invention. The LED array is a blue LED array or a UV-LED array. The LED light-emitting structure can be any one of a III-V nitride epitaxial structure, a III-V arsenide epitaxial structure, a III-V phosphide epitaxial structure, and a III-V antimonide epitaxial structure. Figure 9 In this process, blue LEDs are selected, and the corresponding quantum dot light conversion film 20 is configured to have red quantum dot luminescent material QDR231, green quantum dot luminescent material QDG232, and blanking pits. Figure 10 In the embodiment shown, a UV-LED is selected, and the quantum dot light conversion film 20 is configured to have QDR231, QDG232, and QDB233.

[0068] This invention provides a manufacturing process for quantum dot light conversion films, which can overcome the limitations of quantum printing process precision and produce quantum dot light conversion films that are suitable for higher resolutions.

[0069] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A manufacturing process for a quantum dot light conversion film, characterized in that, include: Step 1: Provide a substrate, form a plurality of patterned small holes on one side surface of the substrate, and open a large hole with a certain depth on the other side of the substrate. The opening area S2 of the large hole is greater than the opening area S1 of the small hole, so that the large hole is fluidly connected to N of the small holes, where N is a natural number greater than or equal to 1. Step 2: Provide a transparent substrate, wherein the transparent substrate has a plurality of patterned recesses, and the opening area of ​​the recesses is S3; Step 3: Align and bond the substrate with the transparent substrate so that each of the small holes corresponds to the pits; Step 4: Add quantum dot luminescent material into the large hole, so that the quantum dot luminescent material is transferred into the pit through the small hole; Step 7: Move the substrate and repeat steps 3 to 4 above until all the predetermined pits are filled. The manufacturing process also includes a step of curing the quantum dot luminescent material in the pit.

2. The manufacturing process of a quantum dot light conversion film according to claim 1, characterized in that: Step 3 also includes an adhesion enhancement process between the substrate and the transparent substrate.

3. The manufacturing process of a quantum dot light conversion film according to claim 2, characterized in that: Steps 5 and 6 are inserted between steps 4 and 7. Step 5 is to solidify the quantum dot light-emitting material, and step 6 is to debond the substrate and the transparent substrate.

4. The manufacturing process of a quantum dot light conversion film according to claim 2, characterized in that: In step 3, a photoresist adhesive is used to bond the substrate and the transparent substrate together.

5. The manufacturing process of a quantum dot light conversion film according to claim 3, characterized in that: In step 7, when the substrate is moved, the residue on the surface of the substrate and the transparent substrate is cleaned.

6. The manufacturing process of a quantum dot light conversion film according to claim 5, characterized in that: The residue is removed by pressurized gas or ultrasonic methods.

7. The manufacturing process of a quantum dot light conversion film according to claim 3, characterized in that: In step 7, the substrate moves in any direction, first filling it with quantum dot luminescent material of the same color, and then filling it with quantum dot luminescent material of different colors.

8. The manufacturing process of a quantum dot light conversion film according to claim 1, characterized in that: In step 7, the process moves along the direction of the quantum dot luminescent material of the same color. After all the quantum dot luminescent materials of the same color are printed, the quantum dot luminescent material is cured in one step.

9. The manufacturing process of a quantum dot light conversion film according to claim 1, characterized in that: In step 4, pressure is required when the quantum dot luminescent material enters the pit through the small hole.

10. The manufacturing process of a quantum dot light conversion film according to claim 1, characterized in that: The substrate is selected from silicon-based substrates, germanium substrates, sapphire substrates, and glass.

11. The manufacturing process of a quantum dot light conversion film according to claim 1, characterized in that: The spacing between two adjacent holes is 0.5~100μm.

12. The manufacturing process of a quantum dot light conversion film according to claim 1, characterized in that: The substrate has a plurality of large holes on the other side, and each of the large holes corresponds to a set of small holes.

13. The manufacturing process of a quantum dot light conversion film according to claim 1, characterized in that: The pits are formed by an etching process, and the interval between two adjacent pits is 0.5 to 100 μm.

14. The manufacturing process of a quantum dot light conversion film according to claim 1, characterized in that: The number of pits on the transparent substrate is 2M or 3M times the number of holes on the substrate, where M is a natural number greater than 1.

15. The manufacturing process of a quantum dot light conversion film according to claim 3, characterized in that: In step 6, the transparent substrate and the substrate are debonded by a sliding process.

16. The manufacturing process of a quantum dot light conversion film according to claim 1, characterized in that: The opening shape of the recess is circular, square, hexagonal, or triangular.

17. The manufacturing process of a quantum dot light conversion film according to claim 1, characterized in that: The bottom of the pit is either flat or curved.

18. The manufacturing process of a quantum dot light conversion film according to claim 1, characterized in that: S3 is greater than or equal to S1.

19. The manufacturing process of a quantum dot light conversion film according to claim 1, characterized in that: In step 4, the quantum dot luminescent material is transferred into the macropores by a printing process or a coating process.

20. The manufacturing process of a quantum dot light conversion film according to claim 1, characterized in that: The pits on the transparent substrate are divided into several groups, and each group includes three pits corresponding to three different colors of quantum dot luminescent materials.

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