Large-size utg anti-wrinkle support positioning system based on coating jig

Abstract

The application discloses a large-size UTG anti-wrinkle supporting and positioning system based on a coating jig and relates to the field of coating jigs.The system comprises a jig base, a bearing module arranged on a basic bearing surface of the coating jig and used for pre-constraining the overall form of a UTG base material according to a preset three-dimensional profile before coating operation, and an isolation module arranged continuously in the circumferential direction around a base material bearing area of the coating jig and used for forming a constant non-contact gap space between the edge of the UTG base material and the jig body.The application can prevent the base material from deviating and the edge from warping by regularizing the form of the UTG base material and positioning the corners, can adapt the gradual supporting structure to the thickness of the base material, can naturally deform, can effectively inhibit the generation of wrinkles by adjusting the force in real time, can stably separate the base material after coating, can avoid damage caused by pulling, and can effectively improve the coating flatness and production yield.

Description

Technical Field

[0001] This invention relates to the field of coating fixture technology, specifically to a large-size UTG anti-wrinkle support and positioning system based on coating fixtures. Background Technology

[0002] Ultra-thin flexible glass (UTG), with its superior properties of being ultra-thin, highly transparent, and bendable, has become the core cover material for foldable screens and flexible touch terminals. Large-size UTG coating and strengthening processes are key steps in its mass production, and processing precision directly affects the performance and appearance quality of the final product. Currently, the industry generally uses traditional fixed coating fixtures for the processing and production of large-size UTG to support and position the substrate. These fixtures, with their core structure of overall rigid support and fixed limiting, are the mainstream tooling equipment in the UTG processing field.

[0003] The utility model patent with application number 202222136979.8 discloses a support platform suitable for UTG coating operations. The application aims to solve the problem that "existing UTG products are generally coated by inkjet or sputtering on a single sheet, which results in inconsistent film quality and high cost".

[0004] However, existing traditional coating fixtures and the aforementioned patented solutions are not adaptable enough and cannot effectively solve the problems of substrate bending, collapse and edge damage in the reinforcement processing of large-size ultra-thin UTG.

[0005] To address this, we propose a large-size UTG anti-wrinkle support and positioning system based on a coating fixture. Summary of the Invention

[0006] In view of the above-mentioned shortcomings of the prior art, the present invention provides a large-size UTG anti-wrinkle support and positioning system based on a coating fixture, which can effectively solve the problems of the prior art.

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions; This invention discloses a large-size UTG anti-wrinkle support and positioning system based on a coating fixture, including a fixture base, and further comprising: The coating fixture consists of several modules: a support module, mounted on the base support surface, which pre-constrains the UTG substrate according to a preset three-dimensional contour before coating; an isolation module, continuously arranged circumferentially around the substrate support area of ​​the coating fixture, which creates a constant non-contact gap between the edge of the UTG substrate and the fixture body; a support module, arranged in a matrix within the substrate support area of ​​the coating fixture, which provides a continuously varying support height along the plane below the non-coated area of ​​the UTG substrate; an equalization module, integrated with each discrete support unit, which adjusts the supporting force of each support unit on the UTG substrate in real time during coating; a locking module, located at the four corners of the substrate support area of ​​the coating fixture, which forms a mechanical interlock with the non-functional areas of the UTG substrate to restrict its in-plane degrees of freedom; and a protection module, linked to all discrete support units and the pre-formed support structure, which ensures that all support structures separate from the UTG substrate simultaneously and at a uniform speed after coating. The support module consists of several discretely distributed support units; The load-bearing module, isolation module, and locking module are rigidly connected and together form the initial positioning reference of the system, and together perform the morphological pre-constraint and position locking of the substrate before coating. The equalization module is electrically connected to all the support units of the support module in a one-to-one correspondence, forming a closed-loop control circuit. The stress sensing data directly drives the real-time adjustment of the support force. The protection module is mechanically linked to all movable structures of the bearing module and support module, and triggers a global synchronous disengagement action in a unified manner after receiving the coating completion signal.

[0008] Furthermore, the supporting module includes several parallel and equally spaced preformed strips that can be independently raised and lowered. The spacing between the preformed strips is 10-30mm. The top of the preformed strip is a rounded surface structure with a surface roughness of no more than 0.8μm. The tops of all the preformed strips together constitute the preset three-dimensional contour. The preset three-dimensional contour is a cylindrical arc-shaped protrusion that smoothly transitions from the center of the coating area to the surrounding edges. The protrusion direction is perpendicular to the length direction of the preformed strip. The maximum height of the cylindrical arc-shaped protrusion does not exceed 3 times the thickness of the UTG substrate and is not greater than 50μm.

[0009] Furthermore, the isolation module includes an elastic sealing strip continuously arranged circumferentially around the substrate bearing area and a gap adjustment component linked to the elastic sealing strip. The elastic sealing strip has a continuous vacuum adsorption channel inside, the pore size of the vacuum adsorption channel is 0.2-0.5mm, and the spacing between adjacent channels is 5-10mm. The gap adjustment component adjusts the height of the elastic sealing strip according to a constant gap value G calculated by the following formula, so that the non-contact gap space is formed between the edge of the UTG substrate and the fixture body: ; In the formula: It is a dimensionless proportionality coefficient; The static surface tension of the coating liquid used in the coating operation; The nominal thickness of the UTG substrate; This represents the allowable bending stress of the UTG substrate.

[0010] Furthermore, the elastic sealing strip is made of silicone rubber material with a Shore hardness of 30-40 degrees. The cross-section of the elastic sealing strip is an isosceles trapezoidal structure that is narrower at the top and wider at the bottom. The width of the upper base of the trapezoid is 1-2 mm, the width of the lower base is 2-3 mm, and the height is 3-5 mm.

[0011] Furthermore, each support unit in the support module corresponds to an independent uncoated area of ​​the UTG substrate, and the projection of the support unit is completely located within the corresponding uncoated area. The matrix spacing L of the support units is adjusted according to the thickness of the UTG substrate. When the thickness of the UTG substrate is 20-30μm, L is 5-8mm; When the thickness is 30-50μm, L is 8-12mm; When the thickness is 50-100μm, L is 12-15mm; The support height of each discrete support unit follows a continuous parabolic distribution along the plane. The support height of the (i,j)th support unit is... ; In the formula: This serves as the reference support height for all support units; This is the height adjustment factor; is the straight-line distance from the geometric center of the (i,j)th support unit to the geometric center of the coating area; The equivalent radius of the coating area; The density of the coating liquid; It is the acceleration due to gravity; The nominal thickness of the coating layer; Density of the UTG substrate; The nominal thickness of the UTG substrate; The bending stiffness of the UTG substrate.

[0012] Furthermore, the support unit includes a piezoelectric ceramic actuator and a flexible support head fixed to the top of the piezoelectric ceramic actuator. A miniature thin-film pressure sensor is integrated between the bottom of the flexible support head and the top of the piezoelectric ceramic actuator. The miniature thin-film pressure sensor has a measurement range of 0-1N and an accuracy of not less than 0.01N, and is used to detect the contact pressure between the support unit and the UTG substrate in real time. The top of the flexible support head has a spherical structure with a radius of curvature of 5-10mm. The contact area of ​​the flexible support head is not greater than 0.25mm². The flexible support head is made of polytetrafluoroethylene material.

[0013] Furthermore, the equalization module includes a laser displacement sensor and a piezoelectric ceramic actuator integrated one-to-one with each discrete support unit. The laser displacement sensor is integrated on the side of the corresponding support unit, and the detection point is located on the lower surface of the UTG substrate directly above the support unit. The sampling frequency of the laser displacement sensor is not less than 1000Hz, the measurement accuracy is not less than 1μm, and the response time of the piezoelectric ceramic actuator is not greater than 1ms. During the coating process, the laser displacement sensor detects the deformation of the UTG substrate above the corresponding support unit in real time and calculates the difference between the real-time deformation and the preset reference deformation. The piezoelectric ceramic actuator adjusts the supporting force based on this difference using a closed-loop feedback method: when When the value is positive, increase the supporting force. When the value is negative, the supporting force is reduced, and the adjustment period is no more than 1ms. No. The required adjustment of the support force increment for each support unit ; In the formula: This is a dimensionless force adjustment coefficient; The bending stiffness of the UTG substrate; For the first The difference between the real-time deformation of the UTG substrate above each support unit and the preset reference deformation; It is the horizontal distance between the geometric centers of two adjacent support units.

[0014] Furthermore, the locking module includes flexible grippers and positioning pins respectively disposed at the four corners of the substrate bearing area. The positioning pins extend upward perpendicular to the base bearing surface and are used to insert into the pre-set non-functional positioning holes at the corners of the UTG substrate. The fit gap between the positioning pin and the positioning hole is 5-10μm, forming a gap fit mechanical interlock, which restricts the UTG substrate to three degrees of freedom in the plane: translation along the X-axis, translation along the Y-axis, and rotation around the Z-axis. The clamping surface of the flexible grippers is covered with a silicone buffer layer with a thickness of 0.1-0.3mm, and the clamping length is 3-5mm. It is used to clamp the non-functional edge area of ​​the corners of the UTG substrate, and the clamping force is set to 0.1-0.5N.

[0015] Furthermore, the protection module includes a synchronous drive motor, a main drive shaft, and multiple sets of parallel linkage mechanisms. The linkage mechanisms adopt an equal-length parallelogram structure. All discrete support units and the preformed strips of the load-bearing module are connected to the main drive shaft through corresponding linkage mechanisms. The synchronous drive motor is a stepper motor with a step angle of no more than 0.9°. The synchronous drive motor drives the main drive shaft to rotate, causing all support units and preformed strips to rise and fall at the same linear speed. The linear speed during the separation process is set to 0.1-0.5 mm / s, and the motion synchronization error of all support units and preformed strips is no more than 1 μm.

[0016] Compared with the known prior art, the technical solution provided by this invention has the following beneficial effects: This invention pre-constrains the overall shape of large-size UTG substrates before coating, thus regulating the overall contour of the substrate in advance and avoiding wrinkles induced by substrate deformation from the source. Simultaneously, it maintains a stable and constant non-contact gap between the substrate edge and the fixture, effectively preventing edge lifting and positional shift during coating. The staggered and gradually varying support layout conforms to the natural downward curve formed by the weight of the substrate and coating liquid, adapting to the actual stress state of the substrate. It can also sense subtle substrate deformations in real time and dynamically adjust the support strength to balance stress differences across the entire surface. Corner limiting methods constrain the substrate's planar displacement and rotation, ensuring positioning accuracy throughout the process. After coating, the support structure and substrate can be separated synchronously and uniformly, avoiding stress damage and secondary wrinkles caused by separation and pulling. It is suitable for multi-specification large-size UTG coating production, steadily improving the flatness of the coated substrate surface and reducing the defect rate during production. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0018] Figure 1 This is a schematic diagram of a large-size UTG anti-wrinkle support and positioning system based on a coating fixture. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] The present invention will be further described below with reference to embodiments.

[0021] Example:

[0022] This embodiment features a large-size UTG anti-wrinkle support and positioning system based on a coating fixture, such as... Figure 1 As shown, it includes a jig base and also includes: The support module is set on the base support surface of the coating fixture and is used to pre-constrain the overall shape of the UTG substrate according to the preset three-dimensional contour before the coating operation. The support module includes several parallel and equally spaced preformed strips that can be independently raised and lowered. The spacing between the preformed strips is 10-30mm. The top of the preformed strip is a rounded surface structure with a surface roughness of no more than 0.8μm. The tops of all the preformed strips together form a preset three-dimensional contour. The preset three-dimensional contour is a cylindrical arc-shaped protrusion that smoothly transitions from the center of the coating area to the surrounding edges. The protrusion direction is perpendicular to the length direction of the preformed strip. The maximum height of the cylindrical arc-shaped protrusion does not exceed 3 times the thickness of the UTG substrate and is not greater than 50μm. The radius of curvature of the cylindrical arc protrusion profile is linearly matched with the long side dimension of the UTG substrate. For every 100mm increase in the long side of the substrate, the radius of curvature increases by 800mm. At the same time, for every 10μm increase in the thickness of the substrate, the radius of curvature is slightly increased by 200mm. This is to match the deformation law of the large-size UTG under its own weight and ensure that the preformed profile is completely in line with the natural deformation of the substrate. An isolation module is continuously arranged circumferentially around the substrate bearing area of ​​the coating fixture to create a constant non-contact gap space between the edge of the UTG substrate and the fixture body. The isolation module includes an elastic sealing strip continuously arranged around the substrate bearing area and a gap adjustment component linked to the elastic sealing strip. The elastic sealing strip has a continuous vacuum adsorption channel inside. The pore size of the vacuum adsorption channel is 0.2-0.5mm and the spacing between adjacent channels is 5-10mm. It is used to adsorb the edge of the UTG substrate during the coating process to prevent the edge from lifting. The gap adjustment component adjusts the height of the elastic sealing strip according to the constant gap value G calculated by the following formula, so that a non-contact gap space is formed between the edge of the UTG substrate and the fixture body: ; In the formula: It is a dimensionless proportionality coefficient; The static surface tension of the coating liquid used in the coating operation, expressed in N / m; The nominal thickness of the UTG substrate, in meters (m). The allowable bending stress of the UTG substrate is expressed in Pa. The above formula incorporates the allowable bending stress of the UTG substrate, the substrate thickness, and the static surface tension of the coating liquid as core influencing factors into the gap calculation logic. By adapting the differences in working conditions such as substrate contact angle, edge support stiffness, and coating liquid viscosity through a dimensionless proportional coefficient, it quantifies multiple types of actual operating variables into the gap value. It abandons the rough mode of traditional manual gap estimation and can accurately calculate a constant gap that is suitable for the current working conditions, so that the substrate edge and the fixture always maintain a stable non-contact state, thus suppressing edge warping and wrinkle generation from the source. in, The range of values ​​is The value is larger when the contact angle between UTG and coating liquid is larger, the edge support stiffness is higher, and the kinematic viscosity of coating liquid is higher, and the value is smaller when these conditions are met. In actual working conditions, the contact angle between UTG and the coating liquid is measured using a contact angle measuring instrument at a standard temperature of 25℃, sampling multiple points on the non-functional area of ​​the substrate edge; the edge support stiffness is measured using a static pressure deformation testing device to determine the flexural modulus of the fixture edge support structure; the kinematic viscosity of the coating liquid is measured using a capillary viscometer according to the national standard for coating liquids in the industry. By substituting the quantified values ​​of these three tests into a preset working condition matching table, the corresponding working condition can be uniquely determined. The precise value can be obtained without the need for human experience to estimate; The elastic sealing strip is made of silicone rubber with a Shore hardness of 30-40 degrees. The cross-section of the elastic sealing strip is an isosceles trapezoidal structure that is narrower at the top and wider at the bottom. The width of the upper base of the trapezoid is 1-2mm, the width of the lower base is 2-3mm, and the height is 3-5mm. The support modules are arranged in a matrix discrete manner within the substrate bearing area of ​​the coating fixture, and are used to provide a support height that varies continuously along the planar direction below the uncoated area of ​​the UTG substrate. Each support unit in the support module corresponds to an independent uncoated area of ​​the UTG substrate. The projection of the support unit is completely located within the corresponding uncoated area. The matrix spacing L of the support units is adjusted according to the thickness of the UTG substrate. When the thickness of the UTG substrate is 20-30μm, L is 5-8mm; When the thickness is 30-50μm, L is 8-12mm; When the thickness is 50-100μm, L is 12-15mm; The support height of each discrete support unit follows a continuous parabolic distribution along the plane. The support height of the (i,j)th support unit is... ; In the formula: This is the reference support height for all support units, in meters (m). This is the height adjustment factor, with a value range of 0.5-1.0; is the straight-line distance from the geometric center of the (i,j)th support unit to the geometric center of the coating area, in meters; The equivalent radius of the coated area is in meters. The density of the coating liquid is expressed in kg / m³. This is the acceleration due to gravity, expressed in m / s². The nominal design thickness of the coating layer, in meters (m). Density of UTG substrate, in kg / m³; The nominal thickness of the UTG substrate, in meters (m). Let N be the bending stiffness of the UTG substrate, in N·m. ; The room temperature elastic modulus of the UTG substrate is expressed in Pa. Poisson's ratio for UTG substrate, dimensionless; Among them, the room temperature elastic modulus E and Poisson's ratio v of UTG substrate were measured according to GB / T39814-2021 standard for testing mechanical properties of ultra-thin flexible glass. The test environment was a constant environment of room temperature 25℃ and humidity 50%. The test sample was a standard sample of 50mm×50mm cut from the same batch of UTG substrate. The average value of multiple test sets was taken as the parameter value to be used in the final calculation to ensure the uniformity of parameters and the accuracy of calculation. The above formula takes the reference support height as the basis, combines the distance of the support unit relative to the coating center and the equivalent radius of the coating area, comprehensively considers the coating liquid and the gravity load of the substrate itself, and introduces the bending stiffness of the substrate to characterize its own deformation characteristics. Based on the parabolic distribution law, the support height of each point is arranged, and the height adjustment coefficient can also adapt to the degree of substrate sagging deformation, which conforms to the natural deformation law of large-size UTG substrate and smoothly disperses the internal stress of the board surface. Among them, the height adjustment coefficient The value approaches 1 as the substrate sags and deforms, and approaches 0.5 as the deformation is smaller. The support unit includes a piezoelectric ceramic actuator and a flexible support head fixed to the top of the piezoelectric ceramic actuator. A miniature thin-film pressure sensor is integrated between the bottom of the flexible support head and the top of the piezoelectric ceramic actuator. The measurement range of the miniature thin-film pressure sensor is 0-1N, and the accuracy is not less than 0.01N. It is used to detect the contact pressure between the support unit and the UTG substrate in real time. The top of the flexible support head is a spherical structure with a radius of curvature of 5-10mm. The contact area of ​​the flexible support head is not greater than 0.25mm². The flexible support head is made of polytetrafluoroethylene material. In practical selection, a UTG substrate thickness of 20~30μm is suitable for the contact area. 30~50μm fit 50~100μm fit Within the limit range, the contact area is matched by increasing the thickness of the substrate, which not only ensures uniform support force, but also prevents local indentation damage to ultra-thin substrates. The equalization module is integrated with each discrete support unit and is used to adjust the magnitude of the support force of each support unit on the UTG substrate in real time during the coating process. The equalization module includes laser displacement sensors and piezoelectric ceramic actuators integrated one-to-one with each discrete support unit. The laser displacement sensor is integrated on the side of the corresponding support unit, and the detection point is located on the lower surface of the UTG substrate directly above the support unit. The sampling frequency of the laser displacement sensor is not less than 1000Hz, the measurement accuracy is not less than 1μm, and the response time of the piezoelectric ceramic actuator is not greater than 1ms. During the coating process, the laser displacement sensor detects the deformation of the UTG substrate above the corresponding support unit in real time and calculates the difference between the real-time deformation and the preset reference deformation. The piezoelectric ceramic actuator adjusts the supporting force based on this difference using a closed-loop feedback method: when When the value is positive, the supporting force is increased. When the value is negative, the supporting force is reduced, and the adjustment period is no more than 1ms. No. The required adjustment of the support force increment for each support unit ; In the formula: This is a dimensionless force adjustment coefficient, with a value range of 0.9-1.1; The bending stiffness of the UTG substrate; For the first The difference between the real-time deformation of the UTG substrate above each support unit and the preset reference deformation, in meters; This is the horizontal distance between the geometric centers of two adjacent support units, in meters. The constant 192 in the formula is derived from the small deflection bending mechanics model of a simply supported thin plate. In this embodiment, the matrix discrete support unit is equivalent to the uniformly distributed simply supported support constraint of the thin plate. This constant has unique applicability within the small deformation and elastic deformation range of the UTG substrate. When the small deflection elastic deformation range is exceeded, this formula is no longer applicable and the mechanical modeling and calculation of the support force compensation amount need to be redone. The above formula uses the bending stiffness of the substrate, the real-time deformation difference, and the spacing of the support unit matrix to construct a mechanical conversion relationship. Combined with a dimensionless adjustment coefficient that can be flexibly adjusted according to the substrate thickness and coating liquid load, it accurately calculates the required support force compensation for each support unit. This adapts to the dynamic deformation characteristics of the substrate during the coating process, overcomes the shortcoming that fixed support force cannot be adaptively adjusted, and achieves millisecond-level force fine adjustment with closed-loop feedback, thereby ensuring a smooth and wrinkle-free board surface throughout the coating process. Among them, the smaller the UTG substrate thickness and the larger the coating liquid load, the larger the substrate thickness and the smaller the coating liquid load, the smaller the β value. The laser displacement sensor detects the deformation of the UTG substrate above the corresponding support unit in real time. With the unloaded, calibrated flat reference position corresponding to a preset reference deformation of 0, the sensor's actual reading is the real-time deformation. The algebraic difference between the two is... ; The locking module is located at the four corners of the substrate bearing area of ​​the coating fixture, and is used to form a mechanical interlocking relationship with the non-functional area of ​​the UTG substrate to restrict its in-plane degrees of freedom. The locking module includes flexible grippers and positioning pins respectively set at the four corners of the substrate bearing area. The positioning pins extend upward perpendicular to the base bearing surface and are used to insert into the pre-set non-functional positioning holes at the corners of the UTG substrate. The fit gap between the positioning pin and the positioning hole is 5-10μm, forming a gap fit mechanical interlock, which restricts the UTG substrate to three degrees of freedom in the plane: translation along the X-axis, translation along the Y-axis, and rotation around the Z-axis. The clamping surface of the flexible grippers is covered with a silicone buffer layer with a thickness of 0.1-0.3mm and a clamping length of 3-5mm. It is used to clamp the non-functional edge area of ​​the corners of the UTG substrate, and the clamping force is set to 0.1-0.5N. The clamping force increases linearly with the size and thickness of the UTG substrate. For small UTGs of 300mm and below, the clamping force is 0.1~0.25N, and for large UTGs of 300mm and above, the clamping force is 0.25~0.5N. The mating clearance is set according to the thickness of the substrate. For substrates of 20~50μm, the clearance is 5~7μm, and for substrates of 50~100μm, the clearance is 7~10μm. This satisfies the requirements for planar positioning and locking, and avoids substrate extrusion deformation caused by thermal expansion and contraction. The protection module is linked to all discrete support units and preformed load-bearing structures to ensure that all support structures separate from the UTG substrate simultaneously and at a uniform speed after coating is completed. The protection module includes a synchronous drive motor, a main drive shaft, and multiple sets of parallel linkage mechanisms. The linkage mechanisms adopt an equal-length parallelogram structure. All discrete support units and the preformed strips of the load-bearing module are connected to the main drive shaft through the corresponding linkage mechanisms. The synchronous drive motor is a stepper motor with a step angle of no more than 0.9°. The synchronous drive motor drives the main drive shaft to rotate, causing all support units and preformed strips to rise and fall at the same linear speed. The linear speed during the separation process is set to 0.1-0.5 mm / s, and the motion synchronization error of all support units and preformed strips is no more than 1 μm. The synchronization error is calculated using the two ends of all preformed strips and the center point of each support unit as a unified detection benchmark. The synchronization deviation is calculated by using a laser interferometer to collect motion displacement data at multiple points in real time. The separation line speed is matched positively according to the substrate thickness. For substrate thicknesses of 20~30μm, 0.1~0.2mm / s is selected; for 30~50μm, 0.2~0.35mm / s is selected; and for 50~100μm, 0.35~0.5mm / s is selected. For every 5μm increase in coating thickness, the separation speed is increased by 0.05mm / s. The support module consists of several discretely distributed support units; The load-bearing module, isolation module, and locking module are rigidly connected and together form the initial positioning reference of the system. They jointly perform morphological pre-constraint and position locking of the substrate before coating. The equalization module and all support units of the support module are electrically connected one-to-one to form a closed-loop control circuit, and the stress sensing data directly drives the real-time adjustment of the support force. The protection module, load-bearing module, and support module are all mechanically linked, and upon receiving the coating completion signal, they trigger a unified global synchronous disengagement action.

[0023] In this embodiment, during system operation, the system first powers on and inputs key parameters of the UTG substrate and coating liquid, completing the parameter configuration of each module and the overall machine linkage self-test; then, it adjusts the pre-forming strip of the bearing module to construct an arc-shaped protrusion contour that smoothly transitions from the center to the edge, completing the pre-constraint of the UTG substrate shape; the elastic sealing strip of the isolation module is adjusted by formula calculation to form a constant non-contact gap between the substrate edge and the fixture, and vacuum adsorption is activated to prevent edge lifting; the support module units are arranged in a matrix according to the substrate thickness, the bending stiffness and support height are calculated, a parabolic continuous support height field is formed, and the performance of the sensing and support components is verified; the UTG substrate is then placed... The substrate is aligned and placed, and the locking module's positioning pins and flexible grippers form a mechanical interlock, restricting the substrate's planar freedom and securing it firmly. The balancing module is calibrated under no-load conditions, establishing a closed-loop control circuit and entering standby mode. During the coating process, the laser displacement sensor collects the substrate's deformation in real time, dynamically adjusting the force of each support unit in a closed loop. Combined with real-time feedback from the pressure sensor, it adaptively balances the force and prevents wrinkles. After coating, the protection module synchronously drives all support units to separate from the pre-formed strip at a uniform speed, ensuring no pulling damage to the substrate. Finally, the locking and adsorption are released, the finished substrate is removed, and the equipment is reset, cleaned, and put into standby mode.

[0024] In the above embodiments, the system pre-regulates the shape and positions the edges of large-size UTG substrates, precisely constrains the displacement and rotation deviation of the substrates, and maintains uniform gaps at the edges to effectively prevent edge curling during coating. It can match and adapt the support spacing and gradient height according to the substrate thickness, conforming to the natural deformation caused by the weight of the substrate and coating liquid. During operation, it can sense the slight deformation of the board surface in real time and dynamically adjust the support force to balance the overall force and suppress wrinkles from the source. After coating, the overall structure is synchronously and smoothly detached from the substrate to avoid pulling damage. It is suitable for multi-specification ultra-thin UTG coating production, effectively improving board surface flatness and production yield.

[0025] See the application examples of the system in the above embodiments: This system is applied to the mass production coating of optical functional coatings on large-size ultra-thin UTG glass substrates for foldable screen electronic products. This practical demonstration uses a commercially available UTG substrate with dimensions of 300mm × 400mm and a nominal thickness of 40μm. The substrate's room-temperature elastic modulus, Poisson's ratio, and allowable flexural stress all meet industry-standard mass production parameters. It is paired with a conventional optical coating liquid, whose static surface tension, density, and kinematic viscosity are all standard parameters for the production line. The nominal coating thickness is designed to be 25μm. The entire system uses a fixture base as its basic support carrier, integrating six functional modules: a support module, an isolation module, a support module, a balancing module, a locking module, and a protection module. It sequentially completes the entire process flow, including pre-constraining and locking the UTG substrate's shape and position before coating, dynamic anti-wrinkle support and stress balancing adjustment during coating, and synchronous, non-destructive separation of the substrate and support structure after coating.

[0026] The support module is equipped with multiple parallel and equally spaced independently liftable pre-forming strips. In this application, the spacing between the pre-forming strips is set to 20mm, which is within the reasonable range of 10mm to 30mm as defined by the technical solution. The top of the pre-forming strip is machined into an arc surface structure with a surface roughness controlled at 0.7μm, meeting the accuracy requirement of no more than 0.8μm. The tops of all the pre-forming strips together form a preset three-dimensional contour. This contour presents a cylindrical arc-shaped protrusion that smoothly transitions from the center of the coating area to the surrounding edges. The protrusion direction is perpendicular to the length direction of the pre-forming strip. After process matching calculation, the maximum height of the cylindrical arc-shaped protrusion is determined to be 45μm, which does not exceed the limit of three times the thickness of the UTG substrate and is also controlled within the upper limit of 50μm. Relying on this shaped contour, the overall shape of the large-size UTG substrate is pre-constrained before the formal coating operation, correcting the inherent warping and micro-deformation of the substrate in advance, and avoiding the basic causes of wrinkles during the coating process from the source of the process.

[0027] The isolation module is continuously arranged around the substrate bearing area of ​​the coating fixture, and is composed of an elastic sealing strip and a gap adjustment component. The elastic sealing strip is made of silicone rubber with a Shore hardness of 35, which meets the design standard of 30 to 40 degrees hardness. The cross-section of the sealing strip is processed into an isosceles trapezoidal structure with a narrow top and a wide bottom. The upper base width is 1.5 mm, the lower base width is 2.5 mm, and the overall height is 4 mm. All structural dimensions conform to the technical specifications. The sealing strip has a continuous vacuum adsorption channel inside, with a channel diameter of 0.35 mm and a spacing of 7 mm between adjacent channels. During operation, the vacuum adsorption channel continuously adsorbs the edge of the UTG substrate, effectively preventing the substrate edge from lifting or turning up. The gap adjustment component, taking into account parameters such as the allowable bending stress of the UTG substrate, substrate thickness, and static surface tension of the coating liquid, calculates a constant non-contact gap of 28 μm between the substrate edge and the fixture body. This allows for precise adjustment of the installation height of the elastic sealing strip, stably maintaining the preset gap space. In this application, the dimensionless proportionality coefficient is set to 3.5 × 10⁻⁶. -5 It adapts to the actual working conditions of the UTG-coating liquid contact angle, edge support stiffness, and kinematic viscosity of the coating liquid in this scenario.

[0028] The support module arranges several support units in a matrix discrete manner within the substrate bearing area of ​​the coating fixture. Since the thickness of the UTG substrate used in this case is 40μm, which falls within the thickness range of 30μm to 50μm, the spacing between the support unit matrix is ​​set to 10mm. Each support unit corresponds to an independent uncoated area of ​​the UTG substrate. The projection range of the support unit falls entirely within the corresponding uncoated area, and will not cause contact interference to the substrate coating functional area. The support height of all discretely arranged support units exhibits a continuous parabolic distribution along the plane. Based on calculations of the on-site working conditions, the reference support height of all support units is determined to be 120μm, with a height adjustment coefficient of 0.75 to accommodate the slight sagging deformation of the UTG substrate. Simultaneously, by combining the physical and structural parameters of the UTG substrate, such as its elastic modulus, Poisson's ratio, density, coating liquid density, and equivalent radius of the coating area, the support height at each point within the matrix is ​​precisely set. This provides a continuously and gently varying support height in the plane below the uncoated area of ​​the UTG substrate, evenly distributing the deformation stress caused by the substrate's self-weight and the coating liquid load. Each support unit consists of a piezoelectric ceramic actuator and a flexible support head fixed at its top. The flexible support head is made of polytetrafluoroethylene (PTFE) and has a spherical structure at its top with a radius of curvature of 7 mm. The contact area of ​​the support head is controlled at 0.22 mm², which does not exceed the limit requirement of 0.25 mm². A miniature thin-film pressure sensor is integrated between the bottom of the flexible support head and the top of the piezoelectric ceramic actuator. The sensor's measurement range covers 0 to 1 N, and the actual measurement accuracy can reach 0.005 N, which is better than the design standard of no less than 0.01 N. It can accurately detect the contact pressure between the support unit and the UTG substrate in real time.

[0029] The equalization module is integrated with each discrete support unit, consisting of a laser displacement sensor and a piezoelectric ceramic actuator. The laser displacement sensor is fixed to the side of the corresponding support unit, with the detection point directly above the lower surface of the UTG substrate above the support unit. The actual sampling frequency of the sensor is set to 1200Hz, meeting the sampling requirement of no less than 1000Hz, and the measurement accuracy can reach 0.5μm, exceeding the accuracy specification of no less than 1μm. The response time of the matching piezoelectric ceramic actuator is controlled at 0.8ms, meeting the response speed requirement of no more than 1ms. During the coating operation, the laser displacement sensor uses the flat position of the UTG substrate calibrated under no-load conditions as a reference, sets the reference deformation to zero, and collects the actual deformation of the substrate above each support unit in real time. The difference in deformation is obtained by comparing it with the reference value. The system adjusts the support force in real time through the piezoelectric ceramic actuator using a closed-loop feedback method with an adjustment cycle of no more than 1ms. In this application scenario, the dimensionless force adjustment coefficient is selected as 1.0 to match the working conditions of the current UTG substrate thickness and coating liquid load. The specific value of the support force increment of each support unit is obtained through process calculation. When the deformation difference is detected to be positive, the system automatically increases the support force of the support unit. When the deformation difference is negative, the support force is reduced accordingly. The internal stress of the UTG substrate is dynamically balanced throughout the process, and the substrate tension, dents and wrinkles caused by local stress concentration are completely eliminated.

[0030] The locking module is installed at the four corners of the substrate bearing area of ​​the coating fixture, and consists of flexible grippers and positioning pins. The positioning pins extend upwards perpendicular to the bearing surface of the fixture base and are precisely inserted into the pre-drilled non-functional positioning holes at the corners of the UTG substrate. The fit clearance between the positioning pin and the positioning hole is set to 7μm, which is within a reasonable range of 5μm to 10μm, forming a clearance-fit mechanical interlocking structure. This effectively restricts the UTG substrate's three degrees of freedom in the plane: translation along the X-axis, translation along the Y-axis, and rotation around the Z-axis, preventing slight displacement or misalignment of the substrate during the coating process. The gripping surface of the flexible grippers is covered with a 0.2mm thick silicone buffer layer, with an effective gripping length of 4mm. During operation, the grippers fit against the non-functional edge area of ​​the UTG substrate corners, and the gripping force is stably set at 0.3N, which is within a safe gripping range of 0.1N to 0.5N. This ensures the reliability of substrate positioning and locking while avoiding compression damage to the ultra-thin UTG substrate caused by rigid clamping.

[0031] The protection module consists of a synchronous drive motor, a main drive shaft, and multiple sets of parallel linkage mechanisms. The linkage mechanisms employ an equal-length parallelogram structure design. All discrete support units and the preformed strips of the load-bearing module are mechanically connected to the main drive shaft via corresponding linkage mechanisms. The synchronous drive motor is a stepper motor with an actual step angle of 0.75°, less than the design limit of 0.9°. When the coating process is completed and an end trigger signal is received, the synchronous drive motor starts operating, driving the linkage mechanisms through the main drive shaft. This causes all support units and the preformed strips of the load-bearing module to move synchronously and uniformly. The separation linear velocity between the substrate and the support structure is set to 0.3 mm / s, within the specified range of 0.1 mm / s to 0.5 mm / s. The motion synchronization error of the entire movable structure is controlled within 0.6 μm, not exceeding the allowable error value of 1 μm. This ensures synchronous, smooth, and uniform separation of all support structures from the UTG substrate, preventing pulling, impact, and deformation during separation, effectively protecting the integrity of the formed coating layer and the structure of the UTG substrate itself from damage.

[0032] In terms of overall system coordination, the load-bearing module, isolation module, and locking module are rigidly connected to form the initial positioning reference for the entire system. Before coating, they collaboratively pre-constrain the UTG substrate's shape and precisely lock its spatial position. The balancing module and all support units of the support module are electrically connected one-to-one, forming a closed-loop control circuit. Based on substrate deformation and stress sensing data, it directly drives real-time dynamic fine-tuning of the support force. The protection module, load-bearing module, and all movable structures of the support module form a mechanical linkage, triggering a unified global synchronous disengagement action upon receiving the coating completion signal. In this mass production application of a 40μm thick large-size UTG substrate, the system exhibited no defects such as substrate wrinkles, edge warping, positional misalignment, or separation damage throughout the process. The consistency of the coated product's appearance and dimensional accuracy were effectively improved compared to previous methods, and the yield rate was also improved compared to traditional simple fixture production methods.

[0033] In summary, this system pre-constrains the overall shape of large-size UTG substrates before coating, thus regulating the overall contour of the substrate in advance and avoiding wrinkles induced by substrate deformation from the source. Simultaneously, it maintains a stable and constant non-contact gap between the substrate edge and the fixture, effectively preventing edge lifting and positional shift during coating. The staggered and gradually changing support layout conforms to the natural downward curve formed by the weight of the substrate and coating liquid, adapting to the actual stress state of the substrate. It can also sense subtle substrate deformations in real time and dynamically adjust the support strength to balance the stress differences across the entire surface. Corner limiting methods constrain the planar displacement and rotation of the substrate, ensuring positioning accuracy throughout the process. After coating, the support structure and substrate can be separated synchronously and uniformly, avoiding stress damage and secondary wrinkles caused by separation and pulling. It is suitable for multi-specification large-size UTG coating production, steadily improving the flatness of the coated substrate surface and reducing the defect rate during production.

[0034] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A large-size UTG anti-wrinkle support and positioning system based on a coating fixture, comprising a fixture base, characterized in that, Also includes: The support module is set on the base support surface of the coating fixture and is used to pre-constrain the overall shape of the UTG substrate according to the preset three-dimensional contour before the coating operation. An isolation module is continuously arranged circumferentially around the substrate bearing area of ​​the coating fixture to create a constant non-contact gap space between the edge of the UTG substrate and the fixture body. The support modules are arranged in a matrix discretely within the substrate bearing area of ​​the coating fixture to provide a continuously varying support height along the planar direction below the uncoated area of ​​the UTG substrate. The equalization module is integrated with each discrete support unit and is used to adjust the magnitude of the support force of each support unit on the UTG substrate in real time during the coating process. The locking module is located at the four corners of the substrate bearing area of ​​the coating fixture, and is used to form a mechanical interlocking relationship with the non-functional area of ​​the UTG substrate to restrict its in-plane degrees of freedom. The protection module is linked to all discrete support units and preformed load-bearing structures to ensure that all support structures separate from the UTG substrate simultaneously and at a uniform speed after coating is completed. The support module consists of several discretely distributed support units.

2. The large-size UTG anti-wrinkle support and positioning system based on a coating fixture according to claim 1, characterized in that, The supporting module includes several parallel and equally spaced preformed strips that can be independently raised and lowered. The spacing between the preformed strips is 10-30mm. The top of the preformed strip is an arc-shaped structure with a surface roughness of no more than 0.8μm. The tops of all the preformed strips together form the preset three-dimensional contour. The preset three-dimensional contour is a cylindrical arc-shaped protrusion that smoothly transitions from the center of the coating area to the surrounding edges. The protrusion direction is perpendicular to the length direction of the preformed strip. The maximum height of the cylindrical arc-shaped protrusion does not exceed 3 times the thickness of the UTG substrate and is not greater than 50μm.

3. The large-size UTG anti-wrinkle support and positioning system based on a coating fixture according to claim 1, characterized in that, The isolation module includes an elastic sealing strip continuously arranged around the substrate bearing area and a gap adjustment component linked to the elastic sealing strip. The elastic sealing strip has a continuous vacuum adsorption channel inside, the pore size of the vacuum adsorption channel is 0.2-0.5mm, and the spacing between adjacent channels is 5-10mm. The gap adjustment component adjusts the height of the elastic sealing strip according to a constant gap value G calculated by the following formula, so that the non-contact gap space is formed between the edge of the UTG substrate and the fixture body: ； In the formula: It is a dimensionless proportionality coefficient; The static surface tension of the coating liquid used in the coating operation; The nominal thickness of the UTG substrate; This represents the allowable bending stress of the UTG substrate.

4. The large-size UTG anti-wrinkle support and positioning system based on a coating fixture according to claim 3, characterized in that, The elastic sealing strip is made of silicone rubber with a Shore hardness of 30-40 degrees. The cross-section of the elastic sealing strip is an isosceles trapezoidal structure that is narrower at the top and wider at the bottom. The width of the upper base of the trapezoid is 1-2 mm, the width of the lower base is 2-3 mm, and the height is 3-5 mm.

5. The large-size UTG anti-wrinkle support and positioning system based on a coating fixture according to claim 1, characterized in that, Each support unit in the support module corresponds to an independent uncoated area of ​​the UTG substrate. The projection of the support unit is completely located within the corresponding uncoated area. The matrix spacing L of the support units is adjusted according to the thickness of the UTG substrate. When the thickness of the UTG substrate is 20-30μm, L is 5-8mm; When the thickness is 30-50μm, L is 8-12mm; When the thickness is 50-100μm, L is 12-15mm; The support height of each discrete support unit follows a continuous parabolic distribution along the plane. The support height of the (i,j)th support unit is... ; In the formula: This serves as the reference support height for all support units; This is the height adjustment factor; is the straight-line distance from the geometric center of the (i,j)th support unit to the geometric center of the coating area; The equivalent radius of the coating area; The density of the coating liquid; It is the acceleration due to gravity; The nominal thickness of the coating layer; Density of the UTG substrate; The nominal thickness of the UTG substrate; The bending stiffness of the UTG substrate.

6. The large-size UTG anti-wrinkle support and positioning system based on a coating fixture according to claim 1, characterized in that, The support unit includes a piezoelectric ceramic actuator and a flexible support head fixed to the top of the piezoelectric ceramic actuator. A miniature thin-film pressure sensor is integrated between the bottom of the flexible support head and the top of the piezoelectric ceramic actuator. The miniature thin-film pressure sensor has a measurement range of 0-1N and an accuracy of not less than 0.01N, and is used to detect the contact pressure between the support unit and the UTG substrate in real time. The top of the flexible support head has a spherical structure with a radius of curvature of 5-10mm. The contact area of ​​the flexible support head is not greater than 0.25mm². The flexible support head is made of polytetrafluoroethylene material.

7. The large-size UTG anti-wrinkle support and positioning system based on a coating fixture according to claim 1, characterized in that, The equalization module includes a laser displacement sensor and a piezoelectric ceramic actuator integrated one-to-one with each discrete support unit. The laser displacement sensor is integrated on the side of the corresponding support unit, and the detection point is located on the lower surface of the UTG substrate directly above the support unit. The sampling frequency of the laser displacement sensor is not less than 1000Hz, the measurement accuracy is not less than 1μm, and the response time of the piezoelectric ceramic actuator is not greater than 1ms. During the coating process, the laser displacement sensor detects the deformation of the UTG substrate above the corresponding support unit in real time and calculates the difference between the real-time deformation and the preset reference deformation. The piezoelectric ceramic actuator adjusts the supporting force based on this difference using a closed-loop feedback method: when When the value is positive, increase the supporting force. When the value is negative, the supporting force is reduced, and the adjustment period is no more than 1ms. No. The required adjustment of the support force increment for each support unit ; In the formula: This is a dimensionless force adjustment coefficient; The bending stiffness of the UTG substrate; For the first The difference between the real-time deformation of the UTG substrate above each support unit and the preset reference deformation; It is the horizontal distance between the geometric centers of two adjacent support units.

8. The large-size UTG anti-wrinkle support and positioning system based on a coating fixture according to claim 1, characterized in that, The locking module includes flexible grippers and positioning pins respectively disposed at the four corners of the substrate bearing area. The positioning pins extend upward perpendicular to the base bearing surface and are used to insert into the pre-set non-functional positioning holes at the corners of the UTG substrate. The fit gap between the positioning pin and the positioning hole is 5-10μm, forming a gap fit mechanical interlock, which restricts the UTG substrate to three degrees of freedom in the plane: translation along the X-axis, translation along the Y-axis, and rotation around the Z-axis. The clamping surface of the flexible grippers is covered with a silicone buffer layer with a thickness of 0.1-0.3mm, and the clamping length is 3-5mm. It is used to clamp the non-functional edge area of ​​the corners of the UTG substrate, and the clamping force is set to 0.1-0.5N.

9. The large-size UTG anti-wrinkle support and positioning system based on a coating fixture according to claim 1, characterized in that, The protection module includes a synchronous drive motor, a main drive shaft, and multiple sets of parallel linkage mechanisms. The linkage mechanisms adopt an equal-length parallelogram structure. All discrete support units and preformed strips of the load-bearing module are connected to the main drive shaft through corresponding linkage mechanisms. The synchronous drive motor is a stepper motor with a step angle of no more than 0.9°. The synchronous drive motor drives the main drive shaft to rotate, causing all support units and preformed strips to rise and fall at the same linear speed. The linear speed during the separation process is set to 0.1-0.5 mm / s, and the motion synchronization error of all support units and preformed strips is no more than 1 μm.

10. The large-size UTG anti-wrinkle support and positioning system based on a coating fixture according to claim 1, characterized in that, The load-bearing module, isolation module, and locking module are rigidly connected and together form the initial positioning reference of the system, and together perform the morphological pre-constraint and position locking of the substrate before coating. The equalization module is electrically connected to all the support units of the support module in a one-to-one correspondence, forming a closed-loop control circuit. The stress sensing data directly drives the real-time adjustment of the support force. The protection module is mechanically linked to all movable structures of the bearing module and support module, and triggers a global synchronous disengagement action in a unified manner after receiving the coating completion signal.

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