Method for manufacturing flexible substrate, flexible substrate, and display device

Abstract

The application relates to a flexible substrate preparation method, a flexible substrate and a display device, and is applied to the display field.The method comprises the following steps: providing a rigid substrate; forming a flexible substrate on the surface of the rigid substrate; adopting a pattern design on the side of the flexible substrate in contact with the rigid substrate; and stripping the rigid substrate and the flexible substrate to form a flexible substrate.The method helps to control the energy concentration position of laser, improves the stripping precision, and reduces unnecessary thermal damage.

Description

Technical Field

[0001] This application relates to the field of display technology, and in particular to a method for preparing a flexible substrate, the flexible substrate, and a display device. Background Technology

[0002] Flexible organic light-emitting diode (OLED) displays typically use high-temperature resistant polyimide (PI) material as a flexible substrate to achieve good bending performance. In the fabrication process of a flexible OLED display, a rigid glass substrate is used as a support. The flexible OLED display's film layers are then fabricated on the glass substrate. After fabrication, laser lift-off (LLO) technology is used to peel the glass substrate off the flexible substrate, forming the flexible OLED display.

[0003] However, if the laser energy cannot be precisely controlled, the laser will damage the OLED display device; and the laser energy received on the surface of the PI layer is uneven, and the areas on its surface that receive less laser energy are difficult to peel off. During the peeling process, the pulling may cause the film layer in the OLED display device to break, resulting in a reduction in the peeling yield. Summary of the Invention

[0004] Therefore, it is necessary to provide a method for preparing a flexible substrate, a flexible substrate, and a display device to address the technical problem that the flexible substrate may be stretched during the peeling process, causing the film layer in the OLED display device to break and reducing the yield of the peeling process.

[0005] In a first aspect, this application provides a method for fabricating a flexible substrate. The method includes:

[0006] Provide a rigid substrate;

[0007] A flexible substrate is formed on the surface of the rigid substrate, and the side of the flexible substrate in contact with the rigid substrate is patterned.

[0008] The rigid substrate is peeled off from the flexible substrate to form a flexible substrate.

[0009] In one embodiment, peeling the rigid substrate from the flexible substrate to form a flexible substrate includes:

[0010] Laser ablation is performed on the contact points between the rigid substrate and the flexible substrate on the pattern;

[0011] If the contact point becomes loose, the contact line between the rigid substrate and the flexible substrate on the pattern is first laser-ablated.

[0012] The contact surfaces of the rigid substrate and the flexible substrate on the pattern are then laser-ablated to peel the rigid substrate from the flexible substrate, forming the flexible substrate.

[0013] In one embodiment, the method further includes:

[0014] The contact point is laser-ablated using a first laser emission method;

[0015] The contact line is laser-ablated using a second laser emission method;

[0016] The contact surface is laser-ablated using a third laser emission method.

[0017] In one embodiment, the first laser emission method is a point emission method, the second laser emission method is a line scan emission method, and the third laser emission method is an area scan emission method;

[0018] The laser energy emitted by the first laser emission mode, the second laser emission mode, and the third laser emission mode decreases in that order.

[0019] In one embodiment, the thickness of the pattern on the flexible substrate decreases sequentially at the contact point, at the contact line, and at other locations besides the contact point and the contact line.

[0020] In one embodiment, the pattern on the flexible substrate is a grid shape.

[0021] In the above-mentioned method for preparing flexible substrates, when using laser lift-off technology to separate the rigid substrate from the flexible substrate, the side of the flexible substrate that contacts the rigid substrate is patterned. This patterned design helps to control the energy concentration position of the laser, improves the lift-off accuracy, and reduces unnecessary thermal damage.

[0022] Secondly, this application also provides a method for preparing a flexible substrate, the method comprising:

[0023] Provide a rigid substrate;

[0024] A patterned release layer is formed on the surface of the rigid substrate;

[0025] A flexible substrate is formed on the surface of the patterned release layer;

[0026] The rigid substrate is peeled off from the patterned release layer to form a flexible substrate.

[0027] In one embodiment, peeling the rigid substrate from the patterned release layer to form a flexible substrate includes:

[0028] Laser ablation is performed on the contact points between the rigid substrate and the release layer on the pattern;

[0029] If the contact point becomes loose, the contact line between the rigid substrate and the release layer on the pattern is first laser-ablated.

[0030] The contact surfaces of the rigid substrate and the release layer on the pattern are then laser-ablated to peel the rigid substrate from the release layer, forming the flexible substrate.

[0031] In one embodiment, the method further includes:

[0032] The contact point is laser-ablated using a first laser emission method;

[0033] The contact line is laser-ablated using a second laser emission method;

[0034] The contact surface is laser-ablated using a third laser emission method.

[0035] In one embodiment, the first laser emission method is a point emission method, the second laser emission method is a line scan emission method, and the third laser emission method is an area scan emission method;

[0036] The laser energy emitted by the first laser emission mode, the second laser emission mode, and the third laser emission mode decreases in that order.

[0037] In one embodiment, the thickness of the pattern on the release layer decreases sequentially at the contact point, at the contact line, and at other locations besides the contact point and the contact line.

[0038] In one embodiment, the pattern on the peeling layer is a grid shape.

[0039] The above-mentioned method for preparing flexible substrates, by setting a separate release layer with a patterned design, helps to control the energy concentration position of the laser during the separation of the rigid substrate from the release layer, thereby improving the separation accuracy and reducing unnecessary thermal damage.

[0040] Thirdly, this application also provides a flexible substrate, wherein the side of the flexible substrate that contacts the rigid substrate is patterned.

[0041] Fourthly, this application also provides a flexible substrate, including a flexible substrate, which is obtained by peeling a patterned release layer from a rigid substrate.

[0042] Fifthly, this application also provides a display device, the display device comprising the flexible substrate described in the third or fourth aspect. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0044] Figure 1 This is a schematic flowchart of a method for fabricating a flexible substrate in one embodiment;

[0045] Figure 2 This is a schematic diagram of the pattern shape on the flexible substrate side in one embodiment;

[0046] Figure 3 This is a schematic flowchart of a method for fabricating a flexible substrate in another embodiment. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0048] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0049] In related technologies, to avoid damage to the flexible substrate when peeling it from the rigid substrate, a common method is to design a CCD (Charge Coupled Device) laser receiver next to the laser emitter of the laser lift-off (LLO) equipment. By receiving the refracted lines of the laser on the warped surface, the displacement after the laser refraction is detected, the warping height of the substrate is calculated, and finally the laser focusing position is modified so that the laser is always focused on the contact surface between the PI film and the glass substrate, avoiding incomplete carbonization of the PI film and abnormal tearing of the flexible device.

[0050] However, due to fluctuations in laser energy, changes in focusing position, and uneven laser energy received by the PI surface, problems such as black spots on the device, uneven brightness, difficulty in peeling, and device damage are still likely to occur during the peeling process.

[0051] Based on this, this application provides a method for preparing a flexible substrate, wherein the side of the flexible substrate PI that contacts the rigid substrate is patterned. When peeling the rigid substrate from the flexible substrate, the peeling can be performed in the order of dots, lines, and surfaces of the pattern, thereby improving peeling efficiency and reducing damage to the display device.

[0052] refer to Figure 1 This is a schematic flowchart of a method for fabricating a flexible substrate according to an embodiment of this application. Figure 1 As shown, the method includes:

[0053] Step S110: Provide a rigid substrate.

[0054] Step S120: A flexible substrate is formed on the surface of a rigid substrate, and the side of the flexible substrate in contact with the rigid substrate is patterned.

[0055] Step S130: The rigid substrate is peeled off from the flexible substrate to form a flexible substrate.

[0056] The rigid substrate can be a glass substrate.

[0057] Specifically, the flexible substrate may include a first substrate layer, a first barrier layer, and a second substrate layer. The first substrate layer can be made of a flexible or elastic material that can be deformed by extrusion. For example, the first substrate layer can be made of high-temperature resistant polyimide (PI). The first barrier layer is disposed on the surface of the first substrate layer and is made of an inorganic material. The function of the first barrier layer is to absorb energy generated during the laser irradiation process when the flexible substrate is used in an OLED device, thereby reducing the adverse effects of irradiation on the semiconductor layer of the thin-film transistors in the flexible OLED. The second substrate layer is disposed on the first barrier layer, and the material of the second substrate layer is the same as that of the first substrate layer.

[0058] The first substrate layer is disposed on a rigid substrate (such as a glass substrate). Separating the rigid substrate from the flexible substrate specifically involves separating the rigid substrate from the first substrate layer. Laser lift-off (LLO) technology is used for this separation. LLO is a technique that uses laser energy to decompose composite film layers. Laser lift-off can separate the upper deposited layer from the lower substrate layer, reducing the need for etching, grinding, and dicing. More importantly, the separated substrate can be reused.

[0059] In this embodiment, when using laser lift-off technology to separate the rigid substrate from the flexible substrate, the side of the flexible substrate that contacts the rigid substrate is patterned. This patterned design helps to control the energy concentration position of the laser, improves the lift-off accuracy, and reduces unnecessary thermal damage.

[0060] It is understood that the side of the flexible substrate that contacts the rigid substrate employs a patterned design, resulting in various contact forms between the flexible substrate and the rigid substrate, including points, lines, and surfaces. Therefore, during peeling, different laser emission methods can be used for points, lines, and surfaces, making it easier to peel the flexible substrate from the rigid substrate, improving peeling efficiency, and reducing damage to the flexible substrate. Specifically, in an exemplary embodiment, step S130, which peels the rigid substrate from the flexible substrate to form a flexible substrate, includes: laser ablation of the contact points between the rigid substrate and the flexible substrate on the pattern; if the contact points are loose, laser ablation of the contact lines between the rigid substrate and the flexible substrate on the pattern; and laser ablation of the contact surfaces between the rigid substrate and the flexible substrate on the pattern, to peel the rigid substrate from the flexible substrate and form a flexible substrate.

[0061] Specifically, during the separation of the rigid substrate from the flexible substrate, the contact points between the two substrates in the patterned area are first identified. These contact points are then subjected to laser ablation to effectively break the initial bond strength between the flexible substrate and the rigid substrate, causing them to loosen. After the contact points loosen, the laser ablation gradually extends to the contact lines and contact surfaces. Specifically, the contact lines are first ablated along the patterned lines to gradually release the bond at the linear contact points. Then, the entire contact surface is uniformly ablated to ensure that the flexible substrate is completely separated from the rigid substrate.

[0062] In this embodiment, the contact points between the rigid substrate and the flexible substrate on the pattern are first laser-ablated, and then the contact lines and contact surfaces are laser-peeled to achieve complete separation of the rigid substrate and the flexible substrate. This staged separation method, which follows the separation sequence of points, lines, and surfaces, can precisely control the separation process, avoid damage to the flexible substrate, maintain its integrity and functionality, and make the separation process more efficient.

[0063] In an exemplary embodiment, the method further includes: laser ablation of the contact point using a first laser emission method; laser ablation of the contact line using a second laser emission method; and laser ablation of the contact surface using a third laser emission method.

[0064] In this embodiment, by employing different laser emission methods to perform laser ablation on the contact points, contact lines, and contact surfaces of the rigid substrate and the flexible substrate on the pattern, the peeling accuracy and efficiency of the flexible substrate can be greatly improved, ensuring the quality and performance of the final product.

[0065] In one exemplary embodiment, the first laser emission method is a point emission method, the second laser emission method is a line scan emission method, and the third laser emission method is an area scan emission method.

[0066] The laser energy emitted by the first, second, and third laser emission methods decreases in that order.

[0067] In practice, laser ablation is performed on the contact points using a first laser emission method. Specifically, a high-energy, short-pulse laser is applied to the contact points using a point laser emission method to generate high temperatures and rapidly ablate the contact points. Because the light waves are concentrated, the heat can be concentrated in a small area, which can quickly release the bonding force at the contact points.

[0068] Laser ablation of the contact line is performed using a second laser emission method, specifically employing a medium-energy, long-pulse laser to ensure uniform ablation. After the contact point loosens, the thermal energy at the contact line location is further enhanced, thereby gradually detaching the flexible substrate from the rigid substrate, preparing for the final peeling.

[0069] Laser ablation of the contact surface is achieved by using a third laser emission method. Specifically, a low-energy, uniformly distributed laser is used to process the entire contact surface, ensuring that the final slope of the contact area is smooth to release the bonding force between the flexible substrate and the rigid substrate, so as to avoid damage to the flexible substrate and expand the range of laser action.

[0070] In some embodiments, laser emission parameters (such as wavelength) can be determined based on the material of the side of the flexible substrate that contacts the rigid substrate, so that the laser can be adapted to the absorption characteristics of different materials to ensure the highest efficiency.

[0071] In this embodiment, different laser emission methods are used to process different locations, making the peeling process more targeted and flexible, and significantly improving the accuracy of peeling; and the energy settings of each different emission method ensure that the thermally affected area of ​​the material is reduced, thereby minimizing the potential thermal damage to the flexible substrate.

[0072] In one exemplary embodiment, the thickness of the pattern on the flexible substrate decreases sequentially at the contact point, the contact line, and other locations besides the contact point and the contact line.

[0073] Specifically, the pattern thickness is maximized at the contact points to ensure sufficient material support and minimum bonding strength, thereby improving the speed and effectiveness of laser ablation. At the contact lines, the thickness gradually decreases; this transition can be designed to significantly reduce the mechanical strength of the contact lines, facilitating effective subsequent laser ablation. Maintaining a thinner thickness at locations other than the contact points and contact lines reduces material consumption, optimizes the overall performance of the flexible substrate, and further enhances its flexibility.

[0074] In this embodiment, the greater thickness of the contact point ensures short-term connection strength, allowing for effective peeling when the thermal effect is better concentrated on the contact line and contact surface. Reducing the thickness at the contact line position will decrease its bonding strength, making the peeling process smoother. By designing different thicknesses for the pattern, the strength and control during the peeling process can be effectively optimized, which helps to achieve differentiated laser absorption and enhance the peeling effect.

[0075] In one exemplary embodiment, the pattern on the flexible substrate adopts a grid shape.

[0076] Specifically, the pattern on the flexible substrate can be designed as a grid to effectively guide the laser beam and improve the effective absorption of light energy. For example, see reference... Figure 2 The diagram is a schematic representation of a pattern in one embodiment. Each grid may be a triangle or other shapes, and this application does not specifically limit the shape of the grid.

[0077] It is understandable that, in addition to the grid shape, other patterns can also be used in practical applications, as long as they have hollow features and can achieve phased peeling characteristics. This embodiment is only used for illustration and does not limit the shape of the pattern.

[0078] In this embodiment, the pattern on the side of the flexible substrate that contacts the rigid substrate is designed as a grid shape, which can provide better heat conduction and laser focusing while maintaining support strength, improving positioning accuracy, and helping to uniformly disperse laser energy.

[0079] refer to Figure 3 This is a schematic flowchart of a method for fabricating a flexible substrate according to another embodiment of this application, as shown below. Figure 3 As shown, the method includes:

[0080] Step S310: Provide a rigid substrate.

[0081] Step S320: A patterned release layer is formed on the surface of the rigid substrate.

[0082] Step S330: A flexible substrate is formed on the surface of the patterned release layer.

[0083] In step S340, the rigid substrate is peeled off from the patterned release layer to form a flexible substrate.

[0084] The rigid substrate can be a glass substrate.

[0085] Specifically, before fabricating a flexible substrate on a rigid substrate, a patterned release layer can be formed on the surface of the rigid substrate, and then the flexible substrate can be formed on the surface of the patterned release layer. The flexible substrate is formed by peeling the rigid substrate from the patterned release layer. Specifically, the rigid substrate and the patterned release layer are peeled off.

[0086] The material of the patterned release layer can be the same as or different from the material of the substrate layer in the flexible substrate.

[0087] In some embodiments, laser emission parameters (such as wavelength) can be determined based on the material of the release layer, so that the laser can be adapted to the absorption characteristics of different materials to ensure maximum efficiency.

[0088] In this embodiment, by setting a separate release layer with a patterned design, it is possible to control the energy concentration of the laser when separating the rigid substrate from the release layer, thereby improving the separation accuracy and reducing unnecessary thermal damage.

[0089] Similar to step S130, when performing step S340 to peel the rigid substrate from the patterned release layer to form a flexible substrate, the process includes: laser ablation of the contact points between the rigid substrate and the release layer on the pattern; if the contact points are loose, laser ablation of the contact lines between the rigid substrate and the release layer on the pattern; and laser ablation of the contact surfaces between the rigid substrate and the release layer on the pattern to peel the rigid substrate from the release layer and form a flexible substrate.

[0090] In this embodiment, the contact points between the rigid substrate and the release layer on the pattern are first laser-ablated, and then the contact lines and contact surfaces are laser-peeled to achieve complete separation of the rigid substrate and the release layer. This staged separation method, which follows the separation sequence of points, lines, and surfaces, can precisely control the separation process, avoid damage to the flexible substrate, maintain its integrity and functionality, and make the separation process more efficient.

[0091] In an exemplary embodiment, the method further includes: laser ablation of the contact point using a first laser emission method; laser ablation of the contact line using a second laser emission method; and laser ablation of the contact surface using a third laser emission method.

[0092] In this embodiment, by employing different laser emission methods to laser ablate the contact points, contact lines, and contact surfaces of the rigid substrate and the release layer on the pattern, the release accuracy and efficiency of the flexible substrate can be greatly improved, ensuring the quality and performance of the final product.

[0093] In one exemplary embodiment, the first laser emission method is a point emission method, the second laser emission method is a line scan emission method, and the third laser emission method is an area scan emission method.

[0094] The laser energy emitted by the first, second, and third laser emission methods decreases in that order.

[0095] In this embodiment, different laser emission methods are used to process different locations, making the peeling process more targeted and flexible, and significantly improving the accuracy of peeling; and the energy settings of each different emission method ensure that the thermally affected area of ​​the material is reduced, thereby minimizing the potential thermal damage to the flexible substrate.

[0096] In an exemplary embodiment, the thickness of the pattern on the release layer decreases sequentially at the contact point, the contact line, and other locations besides the contact point and the contact line.

[0097] In this embodiment, the greater thickness of the contact point ensures short-term connection strength, allowing for effective peeling when the thermal effect is better concentrated on the contact line and contact surface. Reducing the thickness at the contact line position will decrease its bonding strength, making the peeling process smoother. By designing different thicknesses for the pattern, the strength and control during the peeling process can be effectively optimized, which helps to achieve differentiated laser absorption and enhance the peeling effect.

[0098] In one exemplary embodiment, the pattern on the peel layer is a grid shape.

[0099] In this embodiment, a mesh-shaped membrane design is adopted, which can provide better heat conduction and laser focusing while maintaining support strength, improving positioning accuracy, and helping to uniformly disperse laser energy.

[0100] In one embodiment, this application provides a flexible substrate, including: a flexible substrate, wherein the side of the flexible substrate in contact with a rigid substrate is patterned.

[0101] In another embodiment, this application also provides a flexible substrate, including a flexible substrate obtained by peeling a patterned release layer from a rigid substrate.

[0102] In one embodiment, this application provides a display device including a flexible substrate as described in any of the preceding claims. The flexible substrate can be used to fabricate display devices for smartphones, tablets, automotive audio systems, or other application display panels. For example, the flexible substrate can also be used to manufacture smart billboards.

[0103] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0104] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for preparing a flexible substrate, characterized in that, The method includes: Provide a rigid substrate; A flexible substrate is formed on the surface of the rigid substrate, and the side of the flexible substrate in contact with the rigid substrate is patterned. The rigid substrate is peeled off from the flexible substrate to form a flexible substrate.

2. The method according to claim 1, characterized in that, The step of peeling the rigid substrate from the flexible substrate to form a flexible substrate includes: Laser ablation is performed on the contact points between the rigid substrate and the flexible substrate on the pattern; If the contact point becomes loose, the contact line between the rigid substrate and the flexible substrate on the pattern is first laser-ablated. The contact surfaces of the rigid substrate and the flexible substrate on the pattern are then laser-ablated to peel the rigid substrate from the flexible substrate, forming the flexible substrate.

3. The method according to claim 2, characterized in that, The method further includes: The contact point is laser-ablated using a first laser emission method; The contact line is laser-ablated using a second laser emission method; The contact surface is laser-ablated using a third laser emission method.

4. The method according to claim 3, characterized in that, The first laser emission method is a point emission method, the second laser emission method is a line scan emission method, and the third laser emission method is an area scan emission method; The laser energy emitted by the first laser emission mode, the second laser emission mode, and the third laser emission mode decreases in that order.

5. The method according to any one of claims 2-4, characterized in that, The thickness of the pattern on the flexible substrate decreases sequentially at the contact point, the contact line, and other locations besides the contact point and the contact line.

6. The method according to any one of claims 1-4, characterized in that, The pattern on the flexible substrate is in the form of a grid.

7. A method for preparing a flexible substrate, characterized in that, The method includes: Provide a rigid substrate; A patterned release layer is formed on the surface of the rigid substrate; A flexible substrate is formed on the surface of the patterned release layer; The rigid substrate is peeled off from the patterned release layer to form a flexible substrate.

8. A flexible substrate, characterized in that, The side of the flexible substrate that contacts the rigid substrate is patterned.

9. A flexible substrate, characterized in that, It includes a flexible substrate, which is obtained by peeling a patterned release layer from a rigid substrate.

10. A display device, characterized in that, Includes the flexible substrate as described in claim 8 or 9.

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