Fabrication method of flexible display device

Abstract

This invention relates to a method for fabricating a flexible display device, comprising the following steps: placing the flexible display device to be peeled onto a peeling platform with the device facing the platform; performing laser scanning processing on the interface between the flexible display device and the carrier substrate, wherein the central region is subjected to at least two laser scanning processes with different incident directions, and the peripheral region is subjected to one or fewer laser scanning processes. This fabrication method avoids the influence of foreign particles and defects on the carrier substrate surface on the absorption of laser energy by the flexible substrate, and ensures no detachment or displacement during handling, thereby effectively improving the reliability and yield of the laser peeling process.

Description

Technical Field

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

[0002] In recent years, flexible display and foldable display technologies have developed rapidly, becoming a key focus for universities and research institutes both domestically and internationally, and a crucial technology that display companies and terminal manufacturers are vying to develop. With continuous advancements in manufacturing processes and technologies, flexible displays are becoming increasingly diverse in form, with screen sizes constantly increasing while display quality continues to improve. Terminal manufacturers are also launching flexible and foldable terminal products one after another. Flexible displays use flexible substrate materials as the carrier substrate for the devices, requiring the electrode layer, TFT matrix, display device, and encapsulation layer to all have a certain bending radius to achieve flexibility. Examples include electronic paper, flexible liquid crystal displays, and flexible organic electroluminescent displays. Compared to ordinary displays, flexible displays have many advantages: lightweight, small size, thinness, and portability; stronger resistance to high and low temperatures, impact, and shock, adapting to a wider range of working environments; rollable design, resulting in a more aesthetically pleasing appearance; lower cost due to the use of roll-to-roll production processes; lower power consumption and energy efficiency; and more environmentally friendly organic materials.

[0003] Currently, flexible display products are mainly manufactured using the S2S (sheet-to-sheet) process, using a glass substrate as a carrier and combining methods such as flexible substrate attachment and removal. Attachment and removal involves first attaching the flexible substrate to a rigid carrier substrate to fabricate the display device, and then peeling off the rigid substrate to remove the flexible display device. This method does not affect the manufacturing precision of the display device, and the manufacturing equipment and processes are similar to those used in traditional TFT-LCD manufacturing, requiring no major adjustments. Therefore, it is closer to mass production applications in the short term. The attachment and removal process is broadly divided into two categories: one is laser lift-off (LLO), which uses a laser to directly act on the interface between the plastic substrate and the carrier, breaking the bonding force between the plastic substrate and the carrier through high-energy laser to achieve separation; the other is mechanical lift-off (MLO), which utilizes the different bonding forces between a special release layer and the substrate and carrier substrate, separating them by cutting away the strongly bonded edges. Laser lift-off technology has been applied to the fabrication of flexible displays and has been mass-produced in flexible OLED mobile phones. However, problems still exist, such as low lift-off yield, easy detachment of flexible display devices during handling, and easy slippage of the carrier substrate. Summary of the Invention

[0004] Therefore, it is necessary to provide a method for fabricating flexible display devices with high peeling yield and good handling reliability.

[0005] A method for fabricating a flexible display device includes the following steps:

[0006] A flexible display device to be peeled off is fabricated on a carrier substrate, the flexible display device to be peeled off having a central region and a peripheral region;

[0007] The flexible display device to be peeled off, formed on the carrier substrate, is placed on the peeling platform and the flexible display device to be peeled off is oriented toward the peeling platform.

[0008] The interface between the flexible display device to be peeled off and the carrier substrate is subjected to laser scanning processing, so that the middle area is subjected to at least two laser scanning processes with different incident directions, and the peripheral area is subjected to one or fewer laser scanning processes.

[0009] In the fabrication method of the flexible display device of the present invention, the interface between the flexible display device to be peeled off and the carrier substrate is subjected to at least two laser scanning processes with different incident directions. This ensures that the central region is subjected to at least two laser scanning processes, while the peripheral region is subjected to only one or fewer laser scanning processes. In this way, on the one hand, the laser beam is not repeatedly incident perpendicularly, but rather scanned separately from the side at a certain angle. Points affected by foreign particles and defects in the previous laser scan are treated by the laser in the subsequent scan, and vice versa. Thus, the two laser scanning processes with different incident directions complement each other, preventing foreign particles and defects on the carrier substrate surface from affecting the absorption of laser energy by the flexible substrate. On the other hand, the peripheral region of the flexible substrate is subjected to only one or fewer laser scanning processes, resulting in a stronger adhesion between the flexible substrate and the carrier substrate, ensuring no detachment or displacement during transport. The central region of the flexible substrate undergoes two scans, absorbing stronger laser energy, which is more conducive to the separation of the flexible substrate from the carrier substrate. Therefore, through this preparation method, the adhesion between the flexible substrate in the middle region and the carrier substrate is greatly reduced when the substrate is scanned more than twice. Furthermore, the points corresponding to foreign particles and defects are also scanned once by the laser. Compared with laser vertical incident scanning, this method is more conducive to the separation of the flexible substrate in the middle region from the carrier substrate. Meanwhile, the adhesion between the flexible substrate in the peripheral region and the carrier substrate is greater when the substrate is scanned less than once. This ensures that there is no detachment or displacement during the handling process, thus improving the handling reliability and effectively improving the reliability and yield of the laser peeling process.

[0010] In one embodiment, the interface between the flexible display device to be peeled off and the carrier substrate is laser-scanned to make the adhesion between the flexible display device to be peeled off and the carrier substrate in the middle area less than the adhesion between the flexible display device to be peeled off and the carrier substrate in the peripheral area.

[0011] In one embodiment, after the step of performing laser scanning processing on the interface between the flexible display device to be peeled off and the carrier substrate, the step further includes: separating the flexible display device to be peeled off from the carrier substrate in the peripheral area;

[0012] The flexible display device to be peeled off in the middle area is separated from the carrier substrate.

[0013] In one embodiment, the peripheral area includes a first peripheral area and a second peripheral area located on both sides of the central area; the first peripheral area is subjected to one of the at least two laser scanning processes with different incident directions, and the second peripheral area is subjected to the other of the at least two laser scanning processes with different incident directions.

[0014] In one embodiment, the widths of the first peripheral area and the second peripheral area are 8mm to 17.5mm, respectively.

[0015] In one embodiment, the incident directions of the at least two laser scanning processes with different incident directions are axially symmetric with respect to the normal direction of the carrier substrate.

[0016] In one embodiment, the angle between the incident direction of the laser scanning process and the direction pointing from the first side of the carrier substrate to the opposite second side is defined as the incident angle, and the incident angle of one of the at least two laser scanning processes with different incident directions is an acute angle, and the incident angle of the other laser scanning process is an obtuse angle.

[0017] In one embodiment, one of the at least two laser scanning processes with different incident directions has an incident angle of 60° to 75°, and the other has an incident angle of 105° to 120°.

[0018] In one embodiment, the peripheral region includes a first peripheral region and a second peripheral region located on both sides of the central region, and the step of performing laser scanning processing on the interface between the flexible display device to be peeled off and the carrier substrate includes:

[0019] The first peripheral area and the middle area are subjected to a first laser scanning process using a laser stripping device with a first incident direction, and the second peripheral area and the middle area are subjected to a second laser scanning process with a second incident direction.

[0020] In one embodiment, the output lens group of the laser ablation device is rotated by a drive member, thereby making the first incident direction and the second incident direction different.

[0021] In one embodiment, before the step of separating the flexible display device to be peeled off from the carrier substrate in the peripheral region, the following step is further included:

[0022] The flexible display device to be peeled off and the carrier substrate, after laser scanning, are placed on the separation platform, with the flexible display device to be peeled off positioned between the carrier substrate and the separation platform;

[0023] The separation platform includes a main body and a beveled part. The main body is used to carry the flexible display device to be peeled off and the carrier substrate in the middle area. The beveled part is connected to the main body and is inclined to the side away from the bearing surface of the main body.

[0024] In one embodiment, during the process of separating the flexible display device to be peeled off from the carrier substrate in the peripheral area, the main body of the separation platform vacuum adsorbs the flexible display device to be peeled off in the middle area.

[0025] After separating the flexible display device to be peeled off from the carrier substrate in the peripheral area, the inclined surface of the separation platform vacuum adsorbs the flexible display device to be peeled off in the peripheral area.

[0026] In one embodiment, the step of separating the flexible display device to be peeled off from the carrier substrate in the peripheral area includes:

[0027] A blade is inserted between the flexible display device to be peeled off and the carrier substrate in the peripheral area.

[0028] In one embodiment, separating the flexible display device to be peeled off from the carrier substrate in the intermediate region includes the following steps:

[0029] The carrier substrate is held by a robotic arm, which then moves away from the flexible display device to be peeled off until the carrier substrate is separated from the flexible display device. Attached Figure Description

[0030] Figure 1This is a schematic diagram illustrating the influence of foreign particles and defects on the carrier substrate on laser ablation in the prior art.

[0031] Figure 2 This is a schematic diagram illustrating the problem of flexible display devices detaching during handling in existing technologies.

[0032] Figure 3 This is a schematic diagram of a robotic arm mechanism according to an embodiment of the present invention, where A is a top view and B is a side view;

[0033] Figure 4 This is a schematic diagram illustrating the fabrication of a flexible display device according to an embodiment of the present invention;

[0034] Figure 5 This is a schematic diagram of a single laser scanning process during laser ablation according to an embodiment of the present invention;

[0035] Figure 6 This is a schematic diagram of another laser scanning process during laser stripping according to an embodiment of the present invention;

[0036] Figure 7 This is a schematic diagram of laser scanning processing with two different incident directions according to an embodiment of the present invention;

[0037] Figure 8 This is a schematic diagram of a carrier substrate removal process according to an embodiment of the present invention.

[0038] Explanation of reference numerals in the attached drawings: Main body 21, inclined surface 22, vacuum adsorption hole 23, robotic arm mechanism 30, frame 31, adsorption component 32, PCB adsorption area 33, substrate adsorption area 34, middle area 201, peripheral area 202, carrier substrate 300, flexible substrate 211, water and oxygen barrier layer 212, TFT array 213, device functional layer 214, thin film encapsulation 215, polarizer 216, blade 400. Detailed Implementation

[0039] To facilitate understanding of the present invention, a more comprehensive description is provided below, along with preferred embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to the methods of this invention.

[0041] A method for fabricating a flexible display device according to an embodiment of the present invention includes the following steps S1 to S3:

[0042] S1. A flexible display device to be peeled off is fabricated on a carrier substrate. The flexible display device to be peeled off has a central region and a peripheral region.

[0043] S2. Place the flexible display device to be peeled, which is formed on the carrier substrate, on the peeling platform and make the flexible display device to be peeled face the peeling platform.

[0044] S3. Perform laser scanning processing on the interface between the flexible display device to be peeled off and the carrier substrate, so that the middle area is subjected to at least two laser scanning processes with different incident directions, and the peripheral area is subjected to one or fewer laser scanning processes.

[0045] When current laser lift-off technology is applied to the fabrication of flexible OLED displays, the presence of foreign particles and defects on the carrier glass can severely impact the yield rate of the lift-off process. For example... Figure 1 As shown, because the laser beam is blocked, reflected, or refracted by foreign particles and defects on the carrier glass, the absorption of laser energy by the flexible substrate is affected. This causes the flexible substrate to fail to separate from the carrier substrate at the positions corresponding to the foreign particles and defects, ultimately resulting in damage to the flexible substrate and defects. For example, in the production of small-sized flexible OLED panels, since there are many small panels on a single G6 glass, the impact of foreign particles and defects on the yield may not be significant. However, in the production of large-sized flexible OLED panels, only two 31-inch panels can be arranged on a single G4.5 glass. If one of the panels is affected by foreign particles and defects, then a 50% loss in yield will occur, which is a very serious impact. Furthermore, as... Figure 2 As shown, after laser stripping and scanning the entire surface, the flexible substrate is prone to detachment and slippage during handling, resulting in low handling reliability and affecting process yield.

[0046] In the fabrication method of the flexible display device of the present invention, the interface between the flexible display device to be peeled off and the carrier substrate is subjected to at least two laser scanning processes with different incident directions. This ensures that the central region is subjected to at least two laser scanning processes, while the peripheral region is subjected to only one or fewer laser scanning processes. In this way, on the one hand, the laser beam is not repeatedly incident perpendicularly, but rather scanned separately from the side at a certain angle. Points affected by foreign particles and defects in the previous laser scan are treated by the laser in the subsequent scan, and vice versa. Thus, the two laser scanning processes with different incident directions complement each other, preventing foreign particles and defects on the carrier substrate surface from affecting the absorption of laser energy by the flexible substrate. On the other hand, the peripheral region of the flexible substrate is subjected to only one or fewer laser scanning processes, resulting in a stronger adhesion between the flexible substrate and the carrier substrate, ensuring no detachment or displacement during transport. The central region of the flexible substrate undergoes two scans, absorbing stronger laser energy, which is more conducive to the separation of the flexible substrate from the carrier substrate. Therefore, through this preparation method, the adhesion between the flexible substrate in the middle region and the carrier substrate is greatly reduced when the substrate is scanned more than twice. Furthermore, the points corresponding to foreign particles and defects are also scanned once by the laser. Compared with laser vertical incident scanning, this method is more conducive to the separation of the flexible substrate in the middle region from the carrier substrate. Meanwhile, the adhesion between the flexible substrate in the peripheral region and the carrier substrate is greater when the substrate is scanned less than once. This ensures that there is no detachment or displacement during the handling process, thus improving the handling reliability and effectively improving the reliability and yield of the laser peeling process.

[0047] It is understood that the aforementioned middle area can be a functional area, while the aforementioned peripheral area can be a non-functional area. For example, the middle area can be a display area and the peripheral area can be a non-display area; or the middle area can be a display panel area and the peripheral area can be a cutting area, etc. It is not limited to these, as long as the area actually used for display is completely subjected to at least two laser scanning processes with different incident directions.

[0048] It is understood that the total number of laser scanning processes is not limited to two; for example, three, four, or five processes can be performed, as long as two of the incident directions are different, and the central area receives at least two laser scanning processes with different incident directions, while the peripheral area receives one or fewer laser scanning processes. This ensures that the adhesion between the flexible display device to be peeled off in the central area and the carrier substrate is less than that between the flexible display device to be peeled off in the peripheral area and the carrier substrate. For example, when performing three or more laser scanning processes, one process scans both the peripheral and central areas with a certain incident direction, another process scans the central area with a different incident direction, and the remaining laser scanning processes are all performed on the central area. It is understood that the peripheral area may not be subjected to any laser scanning process, or it may receive one laser scanning process. When subjected to one laser scanning process, the laser energy absorbed in this area is lower, and a weak adhesion remains between the flexible substrate and the carrier substrate. This ensures that there is no detachment or displacement during handling and reduces the difficulty of subsequent separation.

[0049] In a specific example, after the step of laser scanning the interface between the flexible display device to be peeled off and the carrier substrate, the following steps are also included: separating the flexible display device to be peeled off from the carrier substrate in the peripheral area; and separating the flexible display device to be peeled off from the carrier substrate in the middle area.

[0050] In a specific example, the peripheral area includes a first peripheral area and a second peripheral area located on either side of the central area; the first peripheral area is subjected to one of at least two laser scanning processes with different incident directions, and the second peripheral area is subjected to the other of at least two laser scanning processes with different incident directions. Optionally, both the first and second peripheral areas are rectangular. It is understood that the specific irradiation method is not limited to this, and the shapes of the first and second peripheral areas can be adjusted as needed.

[0051] In a specific example, the widths of the first peripheral area and the second peripheral area (i.e., the distance from the end of the first peripheral area or the second peripheral area closest to the middle area to the end furthest from the middle area) are 8mm to 17.5mm, respectively. If the width is less than 8mm, the adhesive force is small, and the risk of the flexible display device falling off during the transfer process is large. If the width is greater than 17.5mm, the adhesive force is large, the separation of the flexible display device from the carrier substrate becomes more difficult, and the utilization rate of the flexible substrate decreases.

[0052] Optionally, the substrate of the flexible display device is polyimide (PI). In a specific example, the substrate of the flexible display device is brown polyimide, and the laser energy for laser scanning is 130 mJ / cm². 2 ~150mj / cm 2 The preferred value is 145 mj / cm. 2In one specific example, the substrate of the flexible display device is transparent polyimide, and the laser energy for laser scanning is 180 mJ / cm². 2 ~220mj / cm 2 Optionally, the width of the laser beam for laser scanning is 700-760 mm, the starting and ending coordinates of the first laser scan are (0,0) and (455,0) respectively, and the starting and ending coordinates of the second laser scan are (460,0) and (5,0) respectively.

[0053] In a specific example, at least two laser scanning processes with different incident directions are each axially symmetrical with respect to the normal direction of the carrier substrate. In this way, the focal length deviation of the laser in the two laser scanning processes is small, the focusing depth of the laser in the two scans is more consistent, the laser energy absorbed by the flexible substrate is also more consistent, and the separation effect is better.

[0054] In a specific example, the angle between the incident direction of the laser scanning process and the direction pointing from the first side of the carrier substrate to the opposite second side is defined as the incident angle. In at least two laser scanning processes with different incident directions, one incident angle is an acute angle, and the other incident angle is an obtuse angle. Optionally, in at least two laser scanning processes with different incident directions, one incident angle is 60°–75°, and the other incident angle is an obtuse angle of 105°–120°. If the laser incident angle is too small, the light reflected from the surface of the carrier substrate may affect the incident light and easily damage the laser beam lens and related components. If the angle is too large, it will increase the area subjected to only one laser scanning process, thus increasing the difficulty of separating the flexible display device from the carrier substrate and reducing the utilization rate of the flexible substrate.

[0055] In a specific example, the peripheral area includes a first peripheral area and a second peripheral area located on either side of the central area. The step of laser scanning the interface between the flexible display device to be peeled off and the carrier substrate includes: performing a first laser scan on the first peripheral area and the central area in a first incident direction using a laser peeling device, and performing a second laser scan on the second peripheral area and the central area in a second incident direction. It can be understood that the laser scanning process can be a linear scan, for example, first performing the first laser scan on the first peripheral area and the central area sequentially, and then performing the second laser scan on the second peripheral area and the central area sequentially. Alternatively, the central area can be scanned multiple times first, and then the peripheral area can be scanned.

[0056] Optionally, the first incident direction and the second incident direction are axially symmetrical with respect to the normal direction of the carrier substrate. Optionally, the angles between the first incident direction and the second incident direction and the direction pointing from the first side of the carrier substrate to the opposite second side are acute and obtuse, respectively. Optionally, the angle between the first incident direction and the direction pointing from the first side of the carrier substrate to the opposite second side is 60° to 75°, and the angle between the second incident direction and the direction pointing from the first side of the carrier substrate to the opposite second side is 105° to 120°.

[0057] In a specific example, the output lens group of the laser lift-off device is rotated by a driving component, thereby differentiating the first incident direction and the second incident direction. The optical path system of the laser lift-off device generally includes an attenuator, a telescope, a homogenizer, and an output lens group. The output lens group is rotated by a driving component such as an electric motor, allowing the corresponding laser beam incident angle on the carrier substrate to be arbitrarily adjusted, thus avoiding foreign particles and defects on the carrier substrate surface from acting on the interface between the flexible substrate and the carrier substrate. Optionally, the laser lift-off mechanism includes one or more of a 308nm excimer laser and a 405nm semiconductor laser, preferably a 308nm excimer laser.

[0058] In a specific example, before the step of separating the flexible display device to be peeled from the carrier substrate in the peripheral area, the following step is also included: placing the flexible display device to be peeled and the carrier substrate after laser scanning processing on the separation platform, and placing the flexible display device to be peeled between the carrier substrate and the separation platform.

[0059] like Figure 8 As shown, the separation platform includes a main body 21 and an inclined surface 22. The main body 21 is used to carry the flexible display device to be peeled off and the carrier substrate in the middle area. The inclined surface 22 is connected to the main body 21 and is inclined to the side away from the bearing surface of the main body 21. Placing the device on the separation platform makes it easier to perform the separation operation.

[0060] In a specific example, during the process of separating the flexible display device to be peeled off from the carrier substrate in the peripheral area, the main body 21 of the separation platform vacuum adsorbs the flexible display device to be peeled off in the middle area; after the flexible display device to be peeled off from the carrier substrate in the peripheral area is separated, the inclined surface 22 of the separation platform vacuum adsorbs the flexible display device to be peeled off in the peripheral area.

[0061] In a specific example, the step of separating the flexible display device to be peeled from the carrier substrate in the peripheral area includes: inserting a blade between the flexible display device to be peeled from the carrier substrate in the peripheral area. After the peripheral area is separated, the middle area, which has undergone more than two laser scanning processes, is very easy to separate. It is understood that the method of separating the peripheral area is not limited to this and can be selected as needed. After the blade is inserted between the flexible display device to be peeled from the carrier substrate in the peripheral area, the inclined surface 22 of the separation platform vacuum-adsorbs the flexible display device to be peeled from the peripheral area. In this way, the flexible display device to be peeled from the carrier substrate can be separated more easily and remain stable during the separation process.

[0062] In one specific example, separating the flexible display device to be peeled off from the carrier substrate in the middle area includes the following steps: the carrier substrate is gripped by a robotic arm, and then the robotic arm moves away from the flexible display device to be peeled off until the carrier substrate and the flexible display device to be peeled off are completely separated. In one specific example, such as... Figure 3 As shown, the stripping device also includes a robotic arm mechanism 30, which includes a frame 31 and multiple adsorption components 32 disposed on the frame 31. The height of the multiple adsorption components 32 is independently adjustable, thereby enabling more flexible and convenient movement of the flexible display device and / or carrier substrate, resulting in more stable and efficient handling. Optionally, the areas at opposite ends of the robotic arm mechanism 30 are PCB adsorption areas 33, where the adsorption components 32 are used to adsorb PCBs. The area between the PCB adsorption areas 33 is a substrate adsorption area 34, where the adsorption components 32 are used to adsorb carrier substrates.

[0063] In a specific example, the fabrication of the flexible display device to be peeled off on the carrier substrate includes the following steps: coating the carrier substrate with a flexible substrate solution, then drying it under high vacuum and heating it at high temperature to form a flexible substrate with uniform thickness; fabricating a water and oxygen barrier layer and a TFT array (such as Oxide-TFT, LTPS TFT) on the flexible substrate; then fabricating the device functional layer and performing thin film encapsulation to complete the fabrication of the flexible display device to be peeled off; and then attaching materials such as polarizers and color filters and bonding the driver IC and PCB.

[0064] Example 1

[0065] This embodiment takes a flexible AMOLED display device as an example and adopts a process scheme of first bonding the IC and then laser peeling off.

[0066] Step 1: Fabrication of Flexible AMOLED Devices

[0067] like Figure 4As shown, a PI solution is coated onto the entire carrier substrate 300 using a slit coating process, followed by high-vacuum drying and high-temperature heating to form a flexible substrate 211 with uniform thickness. A water and oxygen barrier layer 212 and a TFT array 213 (such as Oxide-TFT or LTPS TFT) are then fabricated on the flexible substrate 211. Flexible substrate materials with different temperature resistance properties can be selected according to the different TFT process temperatures.

[0068] Next, the device functional layer 214 is prepared using printing or vapor deposition processes, and a thin film encapsulation 215 is formed to complete the preparation of the AMOLED display device. Then, polarizers 216, color filters and other film materials are attached, and the driver circuit board (PCB) is bonded.

[0069] Step 2: Handling of flexible AMOLED devices

[0070] The flexible display device and the carrier substrate 300 are placed on a peeling platform with the carrier substrate 300 facing upwards, using methods such as... Figure 3 The robotic arm mechanism 30 shown transfers the flexible display device and the carrier substrate 300 into the laser lift-off mechanism. The height of the suction members 32 of the robotic arm mechanism 30 is adjusted to be the same, thus holding the flexible display device and the driving circuit board in place. The flexible display device and the driving circuit board are at the same height, with no relative displacement during transport, preventing the flexible chip-on-film (COF) film from detaching from the bonding points of the carrier substrate 300 and the driving circuit board, which could result in poor bonding.

[0071] The robotic arm mechanism 30 slowly descends, placing the flexible display device face down on the working platform of the laser peeling mechanism. Then, the platform vacuum is activated, firmly holding the flexible display device in place. The robotic arm mechanism 30 then closes the vacuum and exits the equipment.

[0072] Step 3: Laser ablation

[0073] In this embodiment, a 31-inch flexible sample (730mm×460mm×0.5mm in size) is used as an example for illustration. The flexible substrate 211 is a brown PI film.

[0074] First, the output lens group of the laser lifter is rotated by an electric motor to adjust the incident direction of the laser beam, so that the angle α between the incident direction of the laser beam and the direction of the second side opposite to the first side of the carrier substrate 300 is 60°. The laser energy density is set to 130-150 mJ / cm² according to the process conditions. 2Adjust the Z-axis of the platform to 13.5mm, positioning the laser focal plane at the interface between the flexible substrate 211 and the carrier substrate 300. Set the line beam width to 730mm based on the size of the flexible display device, and set the starting coordinates (0,0) and ending coordinates (455,0) for the laser scan. The laser lift-off equipment stage moves forward, and the laser beam is incident at an angle α = 60°, penetrating the carrier substrate 300 and acting at the interface between the flexible substrate 211 and the carrier substrate 300. Foreign particles and defects on the carrier substrate 300 affect the absorption of laser energy by the flexible substrate 211. Figure 5 As shown, the flexible substrate 211 at the corresponding point remains firmly bonded to the carrier substrate 300. Parameters can be adjusted according to product type, equipment model, and specific process.

[0075] Then, the incident direction of the laser beam is adjusted again so that the angle β between the incident direction of the laser beam and the direction from the first side of the carrier substrate 300 to the opposite second side is 120°. The laser energy density, Z-value, and laser beam width are kept constant. The starting coordinates of the laser scan are set to (460,0), and the ending coordinates are set to (5,0). The working platform of the laser stripping device moves in the reverse direction, and the laser beam is incident at an angle β = 120°, penetrating the carrier substrate 300 and acting on the interface between the flexible substrate 211 and the carrier substrate 300. Foreign particles and defects on the carrier substrate 300 still affect the absorption of laser energy by the flexible substrate 211. Figure 6 As shown. However, the points affected by foreign particles and defects during the first laser scan were all treated by the laser in the second scan, while the points affected by foreign particles and defects during the second laser scan had already been treated by the laser in the first scan.

[0076] Overall effect as Figure 7 As shown, the intermediate region 201 formed by the first α-angle = 60° directional scan and the second β-angle = 120° directional scan corresponds to the effective display area (functional area) of the flexible display device. Having undergone two laser scans, it is very easy to peel off. Meanwhile, the starting and ending sides of the scan, due to the incident angle of the laser beam, only undergo a single scan, forming the peripheral region 202, which still retains a weak adhesive force, ensuring that the flexible display device does not detach or shift during handling. Simultaneously, the points corresponding to foreign particles and defects are all subjected to one laser scan. Compared to vertical laser incidence scanning, the adhesive force between the flexible substrate 211 and the carrier substrate 300 is greatly reduced, effectively improving the reliability and yield of the laser peeling process.

[0077] Step 4: Separation of flexible device from carrier glass

[0078] After the laser lift-off process is completed, the robotic arm mechanism 30 descends, the suction unit 32 activates a vacuum, firmly holding the carrier substrate 300 and the drive circuit board. The robotic arm mechanism 30 then lifts up, transferring the flexible display device and the carrier substrate 300 to the separation platform. Figure 8 As shown, the main body 21 and the inclined part 22 of the separation platform correspond to the middle area 201 and the peripheral area 202, respectively. The inclined part 22 is made of wedge-shaped stainless steel with an inclined angle of 3° to 5°. The main body 21 and the inclined part 22 are covered with vacuum adsorption holes 23. The vacuum level of the main body 21 and the inclined part 22 can be controlled independently.

[0079] like Figure 8 As shown, after CCD alignment, the main body 21 undergoes vacuum adsorption. An ultra-thin blade 400 is inserted into the gap between the flexible substrate 211 and the carrier substrate 300 to completely separate the flexible substrate 211 in the peripheral area 202 from the carrier substrate 300. Then, the inclined surface 22 undergoes vacuum adsorption, and the robotic arm mechanism 30 descends again to hold the carrier substrate 300. The relative height of the adsorption members 32 is adjusted so that the adsorption members 32 at both ends of the robotic arm mechanism 30 are curved upwards, slowly raising the edge of the carrier substrate 300 by 2°–3°, waiting 1–2 seconds, then raising it by 3°–5°, waiting 1–2 seconds, and then the robotic arm mechanism 30 is vertically raised at a speed of 3 mm / s–5 mm / s until the carrier substrate 300 is completely separated from the flexible display device.

[0080] 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.

[0081] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for fabricating a flexible display device, characterized in that, Includes the following steps: A flexible display device to be peeled off is fabricated on a carrier substrate, the flexible display device to be peeled off having a central region and a peripheral region; The flexible display device to be peeled off, formed on the carrier substrate, is placed on the peeling platform, and the flexible display device to be peeled off is oriented toward the peeling platform. The interface between the flexible display device to be peeled off and the carrier substrate is subjected to laser scanning processing, so that the middle area is subjected to at least two laser scanning processes with different incident directions, and the peripheral area is subjected to one or fewer laser scanning processes. The peripheral area includes a first peripheral area and a second peripheral area located on both sides of the central area; the first peripheral area is subjected to one of the at least two laser scanning processes with different incident directions, and the second peripheral area is subjected to the other of the at least two laser scanning processes with different incident directions; the angle between the incident direction of the laser scanning process and the direction pointing from the first side of the carrier substrate to the opposite second side is defined as the incident angle, and the incident angle of one of the at least two laser scanning processes with different incident directions is 60° to 75°, and the incident angle of the other laser scanning process is 105° to 120°; After performing laser scanning processing on the interface between the flexible display device to be peeled off and the carrier substrate, the following steps are also included in sequence: Separate the flexible display device to be peeled from the carrier substrate in the peripheral area; Separate the flexible display device to be peeled off from the carrier substrate in the intermediate region; The central area is a functional area, and the surrounding area is a non-functional area.

2. The preparation method according to claim 1, characterized in that, By performing laser scanning on the interface between the flexible display device to be peeled off and the carrier substrate, the adhesion force between the flexible display device to be peeled off and the carrier substrate in the middle area is made less than the adhesion force between the flexible display device to be peeled off and the carrier substrate in the peripheral area.

3. The preparation method according to claim 1, characterized in that, The width of the laser beam used in the laser scanning process is 700mm to 760mm.

4. The preparation method according to claim 1, characterized in that, The widths of the first peripheral area and the second peripheral area are 8mm to 17.5mm, respectively.

5. The preparation method according to claim 1, characterized in that, The incident directions of the at least two laser scanning processes with different incident directions are each axially symmetric with respect to the normal direction of the carrier substrate.

6. The preparation method according to claim 1, characterized in that, The substrate of the flexible display device is brown polyimide, and the laser energy of the laser scanning process is 130 mJ / cm². 2 ~150mj / cm 2 .

7. The preparation method according to claim 1, characterized in that, The substrate of the flexible display device is transparent polyimide, and the laser energy of the laser scanning process is 180 mJ / cm². 2 ~220mj / cm 2 .

8. The preparation method according to any one of claims 1 to 7, characterized in that, The peripheral region includes a first peripheral region and a second peripheral region located on both sides of the central region. The step of performing laser scanning processing on the interface between the flexible display device to be peeled off and the carrier substrate includes: The first peripheral area and the middle area are subjected to a first laser scanning process using a laser stripping device with a first incident direction, and the second peripheral area and the middle area are subjected to a second laser scanning process with a second incident direction.

9. The preparation method according to claim 8, characterized in that, The laser ablation device is driven to rotate the output lens group by a driving component, thereby making the first incident direction and the second incident direction different.

10. The preparation method according to claim 1, characterized in that, Before the step of separating the flexible display device to be peeled off from the carrier substrate in the peripheral area, the following step is also included: The flexible display device to be peeled off and the carrier substrate, after laser scanning, are placed on the separation platform, with the flexible display device to be peeled off positioned between the carrier substrate and the separation platform; The separation platform includes a main body and a beveled part. The main body is used to carry the flexible display device to be peeled off and the carrier substrate in the middle area. The beveled part is connected to the main body and is inclined to the side away from the bearing surface of the main body.

11. The preparation method according to claim 10, characterized in that, During the process of separating the flexible display device to be peeled off from the carrier substrate in the peripheral area, the main body of the separation platform vacuum adsorbs the flexible display device to be peeled off in the middle area. After separating the flexible display device to be peeled off from the carrier substrate in the peripheral area, the inclined surface of the separation platform vacuum adsorbs the flexible display device to be peeled off in the peripheral area.

12. The preparation method according to claim 1, characterized in that, The step of separating the flexible display device to be peeled off from the carrier substrate in the peripheral area includes: A blade is inserted between the flexible display device to be peeled off and the carrier substrate in the peripheral area.

13. The preparation method according to claim 1, characterized in that, Separating the flexible display device to be peeled off from the carrier substrate in the intermediate region includes the following steps: The carrier substrate is held by a robotic arm, which then moves away from the flexible display device to be peeled off until the carrier substrate is separated from the flexible display device.

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