WO2020187093A1

WO2020187093A1 - Circuit substrate, manufacturing method therefor, and micro light-emitting diode display substrate

Info

Publication number: WO2020187093A1
Application number: PCT/CN2020/078623
Authority: WO
Inventors: 赵承潭
Original assignee: 京东方科技集团股份有限公司
Priority date: 2019-03-20
Filing date: 2020-03-10
Publication date: 2020-09-24
Also published as: CN109920815A; CN109920815B

Abstract

Provided are a circuit substrate, a manufacturing method therefor, and a micro light-emitting diode display substrate. The circuit substrate comprises: a substrate, wherein the substrate comprises a plurality of transfer printing areas: a plurality of collimation structures located in the plurality of transfer printing areas, wherein the collimation structure is used for supporting micro light-emitting diodes on the transfer printing areas, so that the micro light-emitting diodes are in a collimated state during transfer printing; and a plurality of fixing structures located in the plurality of transfer printing areas, wherein each fixing structure is used for fixing the corresponding micro light-emitting diode in the transfer printing area corresponding to the fixing structure.

Description

Circuit substrate and manufacturing method thereof and micro-light emitting diode display substrate

Cross references to related applications

This application claims the priority of Chinese Patent Application No. 201910212495.7 filed in China on March 20, 2019, the entire content of which is incorporated herein by reference.

Technical field

The present disclosure relates to the field of display technology, and in particular to a circuit substrate and a manufacturing method thereof, and a micro-light emitting diode display substrate.

Background technique

During the formation process of the micro-light-emitting diode display substrate, it is necessary to mass transfer the micro-light-emitting diode (Micro LED) to the circuit substrate. At present, the light-emitting uniformity of a large number of Micro LEDs is poor and needs to be improved.

Summary of the invention

In a first aspect, embodiments of the present disclosure provide a circuit substrate, the circuit substrate including:

A base substrate, which includes a plurality of transfer regions:

A plurality of collimating structures located in the plurality of transfer areas, wherein the collimating structure is used to support the micro light emitting diodes on the transfer area, so that the micro light emitting diodes are in collimation during the transfer process status;

A plurality of fixing structures located in the plurality of transfer areas, wherein each fixing structure is configured to fix a corresponding micro light emitting diode in a corresponding transfer area of the fixing structure.

Optionally, the collimating structure includes at least two retaining walls, and the end surfaces of the at least two retaining walls away from the base substrate are located on the same plane.

Optionally, the collimating structure includes multiple retaining walls, and the multiple retaining walls surround a ring structure.

Optionally, the collimating structure includes a retaining wall of a closed ring structure.

Optionally, in each transfer area, the end surface of the retaining wall away from the base substrate is parallel to the plane where the base substrate is located.

Optionally, the collimating structure is an elastic structure, and the elastic deformation of the collimating structure when subjected to a force is greater than the plastic deformation.

Optionally, the fixed structure is an elastic structure, and the plastic deformation of the fixed structure when subjected to a force is greater than the elastic deformation.

Optionally, the fixing structure is a light curing glue or a heat curing glue.

Optionally, each fixing structure is located in a space defined by the collimating structure on the transfer area, and the height of the fixing structure before curing from the plane where the base substrate is located is greater than the distance of the collimating structure. The height of the plane where the base substrate is located.

Optionally, the fixing structure of each transfer area is located in the middle of the ring structure formed by a plurality of retaining walls in the transfer area; or the fixing structure of each transfer area is located in the closed area of the transfer area The middle of the retaining wall of the ring structure.

In a second aspect, the embodiments of the present disclosure provide a micro-light-emitting diode display substrate, including a plurality of micro-light-emitting diodes, and the circuit substrate as described in the first aspect, the plurality of micro-light-emitting diodes and the plurality of The printed areas have a one-to-one correspondence, and each micro-light-emitting diode is attached to the fixing structure on the corresponding transfer area of the circuit substrate.

In a third aspect, the embodiments of the present disclosure also provide a method for manufacturing a circuit substrate for manufacturing the circuit substrate according to any one of the first aspects, the method including:

A collimating structure is formed on each transfer area on the base substrate, and the collimating structure is used to support the micro light emitting diode on the transfer area, so that the micro light emitting diode is in alignment during the transfer process. Straight state.

Optionally, the step of forming a collimation structure on each transfer area on the base substrate includes:

Spin-coating a polymer solution on the base substrate and drying to form a polymer film;

A mask is used to expose the polymer film, and the collimation structure is obtained after development.

Description of the drawings

In order to explain the technical solutions of the embodiments of the present disclosure more clearly, the following will briefly introduce the accompanying drawings used in the description of the embodiments of the present disclosure. Obviously, the drawings in the following description are only some embodiments of the present disclosure. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative labor.

FIG. 1 is a schematic structural diagram of a circuit substrate provided by an embodiment of the disclosure;

2 is a schematic structural diagram of another circuit substrate provided by an embodiment of the disclosure;

3 is a schematic diagram of an assembly structure of a circuit substrate provided by an embodiment of the disclosure;

4 is a schematic structural diagram of another circuit substrate provided by an embodiment of the disclosure;

5 is a schematic structural diagram of another circuit substrate provided by an embodiment of the disclosure;

6 is a schematic structural diagram of another circuit substrate provided by an embodiment of the disclosure;

7 is a schematic diagram of another assembly structure of a circuit substrate provided by an embodiment of the disclosure;

FIG. 8 is a schematic flowchart of a method for manufacturing a circuit substrate provided by an embodiment of the disclosure.

detailed description

The technical solutions in the embodiments of the present disclosure will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present disclosure.

During the mass transfer of Micro LEDs, due to the uneven orientation during the transfer operation, the alignment of the Micro LEDs fixed on the circuit substrate is poor, resulting in poor light-emitting uniformity of multiple Micro LEDs, resulting in a micro LED display substrate The overall display effect is poor.

The structure of the micro-light-emitting diode display substrate is a Micro LED array. After the Micro LED structure design is thinned, miniaturized, and arrayed, a large amount is transferred to the circuit substrate, and then a protective layer is generated by physical deposition technology to form a small pitch. Micro LED. While minimizing the size of the display to a great extent, it can also achieve the purpose of individual addressing and individual driving of light for each pixel. Micro LED has the characteristics of not requiring a backlight source and self-luminous. Compared with OLED, Micro LED color is easier and more accurate to debug, and has a simple structure, almost no light consumption, very long service life, high brightness, low power consumption, super Advantages of high resolution and color saturation. The above advantages mainly depend on the biggest feature of Micro LED, that is, the micron-level pitch. Each pixel can be controlled by addressing and driven by a single point to emit light. The main technical difficulty of Micro LED is that after the base crystal is finished, the lighted Micro LED crystal film needs to be transported directly to the drive backplane without packaging, that is, mass transfer technology.

During the massive transfer of Micro LEDs, only the illuminated LED crystal epitaxial layer is transferred, and the original substrate is not transferred. The handling thickness is only 3%. At the same time, the size of Micro LEDs is extremely small, requiring more refined operation technology. . During the transfer and curing process of the Micro LED, due to the uneven direction of the transfer operation during the transfer process of the Micro LED, the collimation of the Micro LED is poor, and the uniformity of the Micro LED's luminescence cannot be guaranteed, that is, it can be guaranteed in one circuit. All the Micro LEDs in the substrate have the same luminous intensity and uniform luminous brightness, which affects the display effect of the micro LED display substrate.

Therefore, the present disclosure provides the following embodiments to effectively solve the technical problem of poor collimation during the mass transfer process of Micro LEDs.

Referring to FIG. 1, FIG. 1 is a schematic structural diagram of a circuit substrate provided by an embodiment of the disclosure. As shown in FIGS. 1 and 2, the circuit substrate 100 includes:

A base substrate 110, which includes a plurality of transfer regions 111:

A plurality of collimating structures 120 formed on the plurality of transfer areas 111, each of the collimating structures 120 is used to support the micro light emitting diode on the transfer area 111, so that the micro light emitting diode is in the transfer process In a collimated state.

In the embodiments of the present disclosure, the circuit substrate 100 mainly includes a base substrate 110, and the base substrate 110 is used to carry Micro LEDs, where the base substrate 110 may be a glass substrate. The base substrate 110 includes a plurality of transfer areas 111. When a large amount of Micro LED is transferred to the base substrate 110, each transfer area 111 is correspondingly provided with a Micro LED.

Specifically, as shown in FIG. 2, each transfer area 111 is provided with a collimating structure 120, and the collimating structure 120 is in a collimated state, that is, perpendicular to the surface of the base substrate 110. As shown in Figure 3, when the Micro LED 200 is placed in the transfer area 111, the collimating structure 120 on the transfer area 111 can support the Micro LED 200, so that the Micro LED 200 is in a collimated state, that is, the lower surface of the Micro LED 200 It is parallel to the upper surface of the base substrate 110.

When disposing the collimating structure 120 on the base substrate 110, the upper and lower surfaces of the collimating structure 120 need to be arranged parallel to the upper surface of the base substrate 110, and the sides of the collimating structure 120 are perpendicular to the base substrate. The upper surface of 110 is arranged so that the collimating structure 120 is in a collimated state. In this way, when the Micro LED 200 is fixed to the base substrate 110 through the collimating structure 120, the collimating structure 120 can support the Micro LED 200 to be in a collimated state. Each transfer area 111 on the base substrate 110 forms a collimation structure 120, thereby ensuring the collimation of the Micro LED 200 arranged on the multiple transfer areas 111, which can ensure the mass transfer of the Micro LED 200 The overall collimation and uniformity.

In the circuit substrate provided by the above-mentioned embodiments of the present disclosure, a plurality of transfer areas for fixing Micro LEDs are formed on the base substrate, and a collimation structure is formed in each transfer area. In this way, a large number of Micro LEDs When transferred to the circuit substrate, the collimation structure of each transfer area can make the Micro LED on the transfer area in a collimated state, thereby ensuring that the multiple Micro LEDs on the circuit substrate have better collimation and optimization The uniformity of light emission of multiple Micro LEDs and the overall display effect of the micro LED display substrate are improved.

In some optional embodiments, the collimating structure 120 includes at least two retaining walls, and the end surfaces of the at least two retaining walls away from the base substrate are located on the same plane. As shown in FIG. 4, the two retaining walls in each transfer area 111 are parallel. As shown in FIG. 6, two retaining walls in each transfer area 111 cross.

In this embodiment, the collimating structure 120 includes at least two retaining walls 121, and the top ends of the at least two retaining walls 121 are at the same height. In this way, the top ends of at least two retaining walls 121 form two supporting points, and the two supporting points are located in a horizontal plane, the horizontal plane is parallel to the upper surface of the base substrate 110, and is used to support the transfer Micro LED 200. The Micro LED 200 is arranged on the top of the at least two retaining walls 121, and the at least two retaining walls 121 support the Micro LED 200 in a collimated state.

In some optional embodiments, as shown in FIG. 5, the collimating structure may include a retaining wall with a closed ring structure.

In this embodiment, the collimating structure is a retaining wall with a closed ring structure, and the tops of the retaining walls forming the closed ring structure have the same height. In this way, the supporting surface formed by the top of the closed ring structure is more stable, and the supported MicroLED A collimation of 200 is even better. In some optional embodiments, the collimating structure 120 may also be a fully enclosed or semi-closed ring structure enclosed by a plurality of retaining walls 121 with the same height. The collimating structure 120 is located parallel to the base substrate 110. The cross-section on the horizontal plane of may be round, square, cross or other shapes, which is not limited in the present disclosure.

In some optional embodiments, the collimating structure 120 may be an elastic structure, and the elastic deformation of the collimating structure 120 when subjected to a force is greater than the plastic deformation.

In this embodiment, the collimating structure 120 selects an elastic structure, and when the collimating structure 120 is subjected to a force, its elastic deformation is greater than the plastic deformation, that is, its recoverable deformation is greater than the unrecoverable deformation, which can ensure the collimating structure After 120 is stressed, it basically returns to its original state, and when there are some special circumstances, such as poor assembly alignment of the collimating structure 120 or uneven bottom surface of the Micro LED 200, the alignment structure 120 can be plastically adjusted to ensure the overall The collimation of the structure.

In this way, during the transfer operation of the Micro LED 200, the Micro LED 200 is transferred and pressed onto the collimation structure 120 of the transfer area 111, and the collimation structure 120 is deformed under the force to buffer the pressing force during the transfer process and avoid the micro LED 200 is damaged. As the elastic potential energy is completely released, the collimation structure 120 basically restores the original collimation state, supporting the Micro LED 200 in the collimation state.

In some optional embodiments, the material for forming the collimating structure 120 may include acrylic and polymer Ploymer materials. When the collimating structure 120 is subjected to an external pressing force, 80% to 90% of the Elastic deformation, and 10% to 20% elastic deformation, stable structure, better collimation support effect.

In some optional embodiments, as shown in FIG. 6, the circuit substrate 100 may further include:

The fixing structure 130 is arranged on the transfer area 111, and the fixing structure 130 is used to fix the Micro LED 200 in the collimated state on the transfer area 111.

In this embodiment, a fixing structure 130 is added to the transfer area 111 of the circuit substrate 100. As shown in FIG. 7, after the micro LED 200 is supported by the collimating structure 120 in a collimated state, the fixing structure 130 can be aligned The Micro LED 200 is fixed on the transfer area 111 to increase the stability of the Micro LED 200.

In some optional embodiments, the fixing structure 130 is an elastic structure, and the plastic deformation of the fixing structure 130 when subjected to a force is greater than the elastic deformation.

The fixing structure 130 is selected as an elastic structure. In this way, in addition to the fixing function, the fixing structure 130 can also provide a certain buffering effect to buffer the force of the Micro LED 200 transferred to the transfer area 111 and protect the Micro LED 200 from damage . The plastic deformation of the fixed structure 130 when subjected to a force is greater than the elastic deformation, and the fixed structure 130 will deform and fix with the fixed state of the Micro LED 200, and the recovery force is small, and the fixed Micro LED 200 is in a collimated state in conjunction with the fixed Micro LED 200. Optionally, the thickness of the fixing structure is greater than the thickness of the collimating structure, so that the Micro LED device is closely adhered to the base substrate.

In some optional embodiments, the fixing structure 130 is a light-curing glue or a heat-curing glue.

In some optional embodiments, in each transfer area, the height of the photocurable glue before curing from the plane where the base substrate is located is greater than the distance between the collimating structure and the plane where the base substrate is located. height. When the Micro LED 200 is attached to the transfer area due to force, the height of the cured photo-curing adhesive can be basically the same as the height of the collimating structure, so that the compacted photo-curing adhesive can fully contact the Micro LED 200 , Making the Micro LED 200 fit closely to the transfer area.

Light curing adhesives, including visible light curing adhesives and ultraviolet (UV) curing adhesives, are one-component and solvent-free. The curing adhesive can be fixed after receiving visible light or ultraviolet radiation. Thermal curing adhesive is a curing adhesive that can be fixed after being heated.

In some optional embodiments, the fixing structure 130 may be doped with a UV curable resin with polyester compounds, such as phthalates, or phthalates/phthalates, = for example, ortho Dioctyl phthalate (Dioctyl Phthalate, DOP for short), Phthalate Esters (PAEs for short), etc. When under pressure, the fixing structure 130 can undergo 60%-80% plastic deformation with external force, and can be fixed after receiving ultraviolet radiation.

In some optional embodiments, the fixing structure of each transfer area is located in the middle of the ring structure formed by a plurality of retaining walls in the transfer area; or the fixing structure of each transfer area is located in the transfer area. The middle of the retaining wall of the closed ring structure in the printed area. As shown in FIGS. 6 and 7, the fixing structure 130 in each transfer area is located in the middle of the area enclosed by the retaining wall 120. In this way, the supporting force received by the Micro LED 200 is uniform, so that a large number of Micro LEDs emit uniform light.

During the process of transferring and attaching the Micro LED 200 to the circuit substrate 100 provided in this embodiment, the source substrate with the Micro LED 200 is in contact with the base substrate 110 under a specific pressure and pressed. In this process, the fixed structure 130 mainly undergoes plastic deformation to fully contact the Micro LED 200, while the collimating structure 120 mainly undergoes elastic deformation to maintain the alignment of the Micro LED 200. Then, the pressure on the upper substrate is released, and the fixing glue is cured under UV or heating high temperature, which is to complete the process of transferring and fixing the Micro LED 200 to the circuit substrate 100.

Referring to FIG. 3, FIG. 3 provides a micro-light-emitting diode display substrate according to an embodiment of the present disclosure, including a plurality of Micro LED 200 and a circuit substrate, and the plurality of micro-light-emitting diodes correspond to the plurality of transfer regions in a one-to-one correspondence. . The circuit substrate may be the circuit substrate 100 provided by any one of the embodiments shown in FIGS. 1 and 2 and FIGS. 4 to 6, and each transfer area 111 of the circuit substrate 100 is fixedly attached with a Micro LED 200.

In the micro-light-emitting diode display substrate provided by the embodiments of the present disclosure, a plurality of transfer areas for fixing the Micro LED are formed on the base substrate of the circuit substrate, and a collimating structure is formed in each transfer area, so that When a huge amount of Micro LED is transferred to the circuit substrate, the collimation structure of each transfer area can make the Micro LED on the transfer area in a collimated state, thereby ensuring the alignment of the multiple Micro LEDs on the circuit substrate It optimizes the luminous uniformity of multiple Micro LEDs and the overall display effect of the micro LED display substrate. For the specific implementation process of the micro-light-emitting diode display substrate provided by the embodiments of the present disclosure, please refer to the above-mentioned FIGS. 1 and 2, and the specific implementation process of the circuit substrate provided by any of the embodiments shown in FIGS. 4 to 6, which will not be described here. Let me repeat them one by one.

Referring to FIG. 8, FIG. 8 is a schematic flowchart of a manufacturing method of a circuit substrate according to an embodiment of the disclosure. The manufacturing method of the circuit substrate is used for manufacturing the circuit substrate as mentioned in the above-mentioned FIGS. 1 to 7. As shown in Figure 8, the method includes:

Step 801: A collimating structure is formed on each transfer area on the base substrate, and the collimating structure is used to support the micro light emitting diode on the transfer area, so that the micro light emitting diode is in the transfer process. In the collimated state.

Optionally, in step 801, the step of forming a collimation structure on each transfer area on the base substrate may include:

In this embodiment, when the circuit substrate is formed, relevant preparation operations are first applied on the base substrate, such as forming a buffer layer, a waterproof layer, and wiring. Then, a spin coating process is used to spin-coat the polymer solution on the base substrate and dry, remove the solvent, and perform a polymerization reaction to form a polymer film. The polymerization reaction used can be curing at 230 degrees Celsius for 30 minutes . Then, a mask is used to expose the polymer film to form a predetermined pattern, and then a development process is used to retain the exposed area and etch away the non-exposed area to form a collimating structure.

The manufacturing method of the circuit substrate provided by the embodiment of the present disclosure is to form a plurality of transfer areas for fixing the Micro LED on the base substrate of the circuit substrate, and to form a collimation structure in each transfer area. When a huge amount of Micro LED is transferred to the circuit substrate, the collimation structure of each transfer area can make the Micro LED on the transfer area in a collimated state, thereby ensuring the alignment of the multiple Micro LEDs on the circuit substrate It optimizes the luminous uniformity of multiple Micro LEDs and the overall display effect of the micro LED display substrate. For the specific implementation process of the manufacturing method of the circuit substrate provided by the embodiments of the present disclosure, please refer to the above-mentioned FIGS. 1 and 2, and the specific implementation process of the circuit substrate provided by any of the embodiments shown in FIGS. 4 to 6, which will not be described here. Let me repeat them one by one.

The above are only specific implementations of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed in the present disclosure. It should be covered within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.

Claims

A circuit substrate, including:

The base substrate, wherein the base substrate includes a plurality of transfer regions:

A plurality of collimation structures located in the plurality of transfer areas, wherein the collimation structure is configured to support the micro light emitting diodes on the transfer area, and make the micro light emitting diodes in the transfer process Collimation state

A plurality of fixing structures located in the plurality of transfer areas, wherein each fixing structure is configured to fix a corresponding micro light emitting diode in a corresponding transfer area of the fixing structure.
The circuit substrate according to claim 1, wherein the collimating structure comprises at least two retaining walls, and the end surfaces of the at least two retaining walls away from the base substrate are located on the same plane.
The circuit substrate according to claim 1, wherein the collimating structure comprises a plurality of retaining walls, and the plurality of retaining walls form a ring structure.
The circuit substrate according to claim 1, wherein the collimating structure comprises a retaining wall of a closed ring structure.
4. The circuit substrate according to any one of claims 2 to 4, wherein, in each transfer area, the end surface of the barrier wall away from the base substrate is parallel to the plane where the base substrate is located.
4. The circuit substrate of claim 1, wherein the collimating structure is an elastic structure, and the elastic deformation of the collimating structure is greater than the plastic deformation when subjected to a force.
3. The circuit substrate according to claim 1, wherein the fixing structure is an elastic structure, and the plastic deformation of the fixing structure when subjected to a force is greater than the elastic deformation.
8. The circuit substrate according to claim 7, wherein the fixing structure is a photocurable adhesive or a thermal curing adhesive.
The circuit substrate according to claim 8, wherein each fixing structure is located in a space defined by the collimating structure on the corresponding transfer area, and in each transfer area, the fixed structure before curing is at a distance from the The height of the plane where the base substrate is located is greater than the height of the collimating structure from the plane where the base substrate is located.
The circuit substrate according to claim 3 or 4, wherein the fixing structure of each transfer area is located in the middle of a ring structure formed by a plurality of retaining walls in the transfer area; or

The fixing structure of each transfer area is located in the middle of the retaining wall of the closed ring structure in the transfer area.
A micro light emitting diode display substrate, comprising a plurality of micro light emitting diodes, and the circuit substrate according to any one of claims 1 to 10,

Wherein, the plurality of micro light-emitting diodes correspond to the plurality of transfer areas one-to-one, and each micro light-emitting diode is attached to a fixing structure on the corresponding transfer area of the circuit substrate.
A method for manufacturing a circuit substrate for manufacturing the circuit substrate according to any one of claims 1 to 10, wherein the method comprises:

A collimating structure is formed on each transfer area on the base substrate, and the collimating structure is used to support the micro light emitting diode on the transfer area, so that the micro light emitting diode is in the transfer process In a collimated state.
The method according to claim 12, wherein the step of forming a collimating structure on each transfer area on the base substrate comprises:

Spin-coating a polymer solution on the base substrate and drying to form a polymer film;

A mask is used to expose the polymer film, and the collimation structure is obtained after development.