Method and system for stress release of metal mask

Abstract

The application provides a stress releasing method and system of a metal mask. Before the cutting process starts, a certain degree of tension release is performed on the product to be released, so as to avoid the arch bridge-shaped rebound phenomenon caused by the rebound of the product to the middle due to the instantaneous release of the tension at the moment when the cutting action is completed. The application calculates the recovery deformation of the product to be released, controls the first distance d1≤d of the product to be released in the X direction, calculates the first deformation average, and judges whether the first deformation average is within the preset range. If yes, the current state of the product to be released is maintained, and cutting is performed. The above steps can be used to determine whether the internal stress of the product to be released is released to a suitable range. The stress releasing method can release the stress before cutting, maintain a suitable tensile stress, avoid wrinkles in the product to be released, and greatly improve the yield of the material after the stress is released.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of display panels, in particular to a stress release method and system of a metal mask plate. BACKGROUND

[0002] An organic light emitting diode (OLED) display panel is a panel using OLED as a display pixel. Compared with a traditional liquid crystal display panel, the OLED display panel has more and more market welcome due to its self-luminous, low power consumption, good color effect, flexible display and other advantages.

[0003] The preparation of an OLED light emitting device generally adopts the mode of evaporating organic materials onto a substrate. The evaporation of organic materials usually needs to use a mask. The mask is mainly used as a pattern transfer master plate and has typical customization features. The mask is divided into a photomask (mask) and a metal mask (shadow mask). The photomask is mainly used in a photolithography process and is made of high-purity quartz glass and is used for manufacturing a circuit. A fine metal mask (FMM) is a key component used in the manufacture of an OLED display and is mainly used for accurately depositing organic materials to form a pixel pattern.

[0004] The manufacturing process of the fine metal mask needs to go through multiple processes. It is found that the cutting process is easy to cause the fine metal mask product to form an arch bridge-shaped rebound, resulting in unqualified fine metal mask products.

[0005] The present application inventors have found through repeated experiments that if the product is not subjected to tensile stress release before cutting, the fine metal mask product is easy to form an arch bridge-shaped rebound in the cutting process. Therefore, it is urgent to provide a stress release method of a metal mask plate, which aims to release the stress of the metal mask plate before the cutting process of the metal mask plate starts, so as to realize the flat cutting of the metal mask plate product. SUMMARY

[0006] The present application provides a stress release method and system of a metal mask plate, which fully releases the tensile stress of the metal mask plate before the cutting process of the metal mask plate starts, realizes the flat cutting of the metal mask plate product, and avoids the phenomenon that the product rebounds to the middle to form an arch bridge-shaped rebound when the tensile stress is released instantaneously at the moment when the cutting action is completed.

[0007] The present application aims to provide a stress release method of a metal mask plate, which is applied to the stress release before cutting of the metal mask plate, and includes the following steps:

[0008] S01, obtaining a first image of a standard product;

[0009] S02, acquiring a second image of the product to be released stress arranged on the product support frame, the product to be released stress is a metal mask in a stretched state;

[0010] S03, comparing the first image and the second image, if there is a difference, calculating the recovery deformation variable d of the product to be released stress in the X direction after the stress is completely released;

[0011] S04, controlling the first distance d1 of the product to be released stress moving in the X direction, and d1≤d;

[0012] S05A, acquiring a third image of the product to be released stress after moving the first distance, comparing the second image and the third image, and calculating the first deformation variable mean of the product to be released stress, if the first deformation variable mean is within the preset range, the current state of the product to be released stress is maintained, and cutting is performed.

[0013] In one embodiment, further comprising:

[0014] S05B, if the first deformation variable mean is not within the preset range, further controlling the product to be released stress to move in the X direction by a second distance d2;

[0015] S06, acquiring a fourth image of the product to be released stress after moving the second distance, comparing the second image and the fourth image, and calculating the second deformation variable mean of the product to be released stress, if the sum of the first deformation variable mean and the second deformation variable mean is within the preset range, the current state of the product to be released stress is maintained, and cutting is performed.

[0016] In one embodiment, in S03, the step of comparing the first image and the second image to determine whether there is a difference comprises:

[0017] The first image and the second image are divided into a plurality of pixel regions respectively, each of the pixel regions includes a plurality of holes;

[0018] By comparing whether the pixel regions at the same position in the first image and the second image exist difference, it is determined whether the first image and the second image exist difference;

[0019] Wherein, if there is at least one pixel region at the same position in the first image and the second image exists difference, then the first image and the second image exist difference;

[0020] The pixel regions at the same position are different in the number of holes included in the pixel regions at the same position, or the size of at least one hole included in the pixel regions at the same position is different.

[0021] In one embodiment, the step of calculating the recovery deformation amount d of the product to be released in the X direction after stress release in S03 includes:

[0022] S10, converting the metal mask product with a high-density micro-porous structure into an equivalent homogeneous structure, wherein the conversion process includes calculating the porosity of the metal mask and correcting the equivalent material parameters of the metal mask in combination with the porosity;

[0023] S20, creating a plane shell model, obtaining the equivalent material parameters, and performing mesh division according to linear quadrilateral shell elements;

[0024] S30, determining the boundary condition type, obtaining the displacement field of each pixel point as the initial displacement input by comparing the first image and the second image, and setting all degrees of freedom of the X=0 end of the constrained metal mask to be 0;

[0025] S40, setting a solver and performing solving calculation, and outputting the calculation result as the full-field X-direction normal stress; the analysis type of the solver is static linear analysis, and the convergence control is default residual tolerance; the default residual tolerance is less than 10 −6 ;

[0026] S50, combining the full-field X-direction normal stress calculated in S40 to calculate the X-direction recovery deformation amount d.

[0027] In one embodiment, in S10, the porosity of the metal mask is , and the porosity is calculated by the following formula (1)-(5) :

[0028] Formula (1);

[0029] Formula (2);

[0030] Formula (3);

[0031] Formula (4);

[0032] Formula (5);

[0033] ​Wherein, D is the diameter of the equivalent hole in the metal mask, m is the diameter of the first hole, n is the diameter of the second hole, m1 is the depth of the first hole, n1 is the depth of the second hole, L is the length of the metal mask, W is the width of the metal mask, TH is the thickness of the metal mask, V1 is the single hole volume of the equivalent hole, N u is the number of equivalent holes on the metal mask, V2 is the total hole volume of the metal mask, and V is the total volume of the material of the metal mask.

[0034] The equivalent material parameter of the metal mask is , and the equivalent material parameter is calculated by the following formula (6) :

[0035] Formula (6).

[0036] Wherein, is the elastic modulus of the metal mask.

[0037] In one embodiment, the full-field X-direction normal stress calculated in S40 is , the full-field X-direction strain size is , and the following formula (7) is satisfied:

[0038] Formula (7).

[0039] In S50, the following formula (8) is used to calculate the X-direction recovery deformation d:

[0040] Formula (8).

[0041] is the sum of the full-field X-direction normal stress, is the maximum strain in the X-direction.

[0042] In one embodiment, the recovery deformation of the product to be released in the X-direction is 3.5mm-5.5mm.

[0043] The sum of the movement distance of the product to be released in the X-direction is in the numerical range of 1.5mm-3.5mm.

[0044] The application also provides a stress release system of a metal mask, which is applied to stress release before cutting of the metal mask, and the product to be released is fixed to a product support frame, and the product to be released is a metal mask in a stretched state.

[0045] The stress release system of the metal mask plate comprises at least a controller, an image shooting assembly, a motor driving assembly and a monitoring device, the controller is signal connected with the image shooting assembly, the motor driving assembly and the monitoring device respectively; the stress release system of the metal mask plate is applicable to the stress release method of any one of the metal mask plates;

[0046] The image shooting assembly is configured to shoot image information of a standard product and the product to be released stress.

[0047] The motor driving assembly is configured to drive the product to be released stress to move in the X direction on the product support frame.

[0048] The monitoring device is configured to monitor the moving distance of the product to be released stress in the X direction.

[0049] The controller is configured to compare the shot image information of the standard product and the product to be released stress, and determine whether there is a difference.

[0050] The controller is configured to calculate the recovery deformation amount of the product to be released stress in the X direction after stress release. ;

[0051] The controller is configured to calculate the average deformation amount of the product to be released stress.

[0052] The controller is configured to determine whether the average deformation amount is within a preset range, if the average deformation amount is within the preset range, the current state of the product to be released stress is maintained, and cutting is performed.

[0053] In one embodiment, the product support frame comprises a support frame, a guide rail, a movable carrier and an adjustable fixing member.

[0054] The support frame is parallel to the product to be released stress and is arranged to extend in the X direction.

[0055] The guide rail is arranged on the support frame.

[0056] The movable carrier is used to carry the product to be released stress and can slide on the guide rail.

[0057] The adjustable fixing member is used to fix the movable carrier on the guide rail to limit the movement of the product to be released stress in the X direction.

[0058] In one embodiment, the product support frame further comprises a limiting member used to limit the recovery distance of the product to be released stress in the X direction and can slide on the guide rail.

[0059] The stress release method and system of the metal mask plate have the following beneficial effects:

[0060] In the present application, before the cutting process starts, a certain degree of tension release is performed on the product to be released stress (when releasing tension, part of the tension is not released, so as to ensure that the product is in a flat state and the length of the product after cutting will not change too much). The stress release method provided in the present application can maximize the avoidance of the phenomenon of arch-shaped rebound of the product caused by the instantaneous release of tension at the moment when the cutting action is completed. In addition, the stress release method provided in the present application calculates the recovery deformation of the product to be released stress, controls the first distance d1≤d of the product to be released stress in the X direction, calculates the first deformation average, and judges whether the first deformation average is within the preset range. If yes, the current state of the product to be released stress is maintained, and cutting is performed. The steps of calculating the first deformation average and judging whether the first deformation average is within the preset range can be used to determine whether the internal stress of the product to be released stress is released to a suitable range. Further, after using the stress release method provided in the present embodiment, whether it is a thin Invar alloy material or a high-precision fine metal mask plate product, the stress can be released before cutting, and the appropriate tensile stress can be maintained to avoid wrinkles in the product to be released stress (Invar alloy thin material, FMM). After the stress is released, the yield rate (cutting effect) of the material is greatly improved. BRIEF DESCRIPTION OF DRAWINGS

[0061] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0062] Figure 1a The schematic diagram of the product with internal stress in the prior art;

[0063] Figure 1b The schematic diagram of the product after releasing the internal stress in the prior art;

[0064] Figure 2 The step flowchart of the stress release method of the metal mask plate provided in the present embodiment;

[0065] Figure 3 The schematic diagram of the detailed structure of the product to be released stress provided in the present embodiment;

[0066] Figure 4 The schematic diagram of the structure of the product to be released stress placed in the product support frame provided in the present embodiment;

[0067] Figure 5a A schematic view of a product after cutting of a metal mask in the prior art;

[0068] Figure 5b A schematic view of a product after cutting after stress release by the stress release method of the metal mask provided by the embodiments of the present application.

[0069] Icon:

[0070] Product support frame 10: support frame 11, guide rail 111, movable carrier 12, adjustable fixing piece 13, limiting piece 14;

[0071] Product to be released stress 20: first surface 21, second surface 22, first hole 211, second hole 221. DETAILED DESCRIPTION

[0072] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0073] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative labor are within the scope of protection of the present application.

[0074] It should be noted that: similar reference numbers and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0075] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product of the present application is usually placed, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, therefore, it cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" and the like are only used for differentiation in description, and cannot be understood as indicating or implying relative importance.

[0076] Moreover, the terms "horizontal", "vertical", and the like are used as terms of convenience to describe the general orientation of components, and do not require absolute horizontal or vertical orientations. For example, "horizontal" merely refers to a direction more horizontal than "vertical", and does not require that the structure be perfectly horizontal, but can be slightly tilted.

[0077] In the description of the present application, it also needs to be explained that, unless otherwise explicitly specified and limited, the terms "set", "install", "connect", "connect" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0078] Figure 1a A schematic diagram of the existing technology of the internal stress of the nickel-iron alloy product. Figure 1b A schematic diagram of the existing technology of the nickel-iron alloy product after releasing the internal stress. It can be seen that Figure 1b The product targeted in the present application is a high-precision fine metal mask product prepared from a nickel-iron alloy material, and there are multiple processes in the preparation process. The inventors have found through repeated experiments that if the product is not subjected to tensile stress release before cutting, the fine metal mask product is prone to form an arch-shaped rebound during cutting. Therefore, it is urgent to provide a stress release method and system for a metal mask, which aims to release the stress of the metal mask before the cutting process of the metal mask begins, so as to realize the flat cutting of the metal mask product.

[0079] Please refer to Figure 2 , a stress release method for a metal mask is provided, which is applied to the stress release before cutting of a metal mask product. The metal mask product before cutting is placed on the product support frame 10 as shown in Figure 4 , and the metal mask is in a stretched state. Specifically, the stress release method for the metal mask product comprises the following steps:

[0080] S01, obtaining a first image of a standard product. In this step, the measurement size of the standard product can be obtained according to the first image. The measurement size includes specific length, width, thickness, hole size and spacing, etc. The standard product is selected from a product that has released internal stress, or a metal mask that has been punched and made (without moving and other processes, it is considered as a product that has released internal stress). The first image can be a mean integration of multiple images of multiple standard products that have released internal stress.

[0081] S02, acquire a second image of the product 20 to be stress-relieving, which is a metal mask in a stretched state, mounted on the product support frame 10. The second image and the first image can be captured by a high-definition camera, and the image information is transmitted to the controller for analysis and calculation.

[0082] S03, compare the first image and the second image. If there is a difference, calculate the recovery deformation of the product 20 to be stressed after the stress is fully released in the X direction. The recovery deformation in this step is the cumulative deformation of the product 20 to be stress-relieving. For example... Figure 4 As shown, the X direction is the length direction of the product 20 to be stressed.

[0083] S04, Controlling the first distance the product 20 to be stressed to be released moves in the X direction. ,and ≤ In this step, a certain amount of stress is released from the product 20 to be stress-relieving, but not completely. Some tensile stress must be retained to ensure that the product 20 remains flat and that its length after cutting does not change significantly. The first distance d1 that the product 20 moves in the X direction in this step can be set as one end moving d1 distance towards the center of the product, or it can be set as both ends moving towards the center simultaneously, each moving d1 / 2. Specifically, moving one end of the product 20 towards the center is easier to control in practical applications.

[0084] S05A: Acquire a third image of the product 20 to be stress-relieving after moving a first distance. Compare the second and third images and calculate the average first deformation value of the product 20. If the average first deformation value is within a preset range, maintain the current state of the product 20 and proceed with cutting. In this step, the average first deformation value is the sum of the calculated deformation values ​​of different pixel regions, divided by the number of pixel regions. The preset range is the average range of deformation values ​​of different pixel regions, typically set to 20nm-100nm.

[0085] In the embodiment, before the cutting process starts, a certain degree of tension release is performed on the product 20 to be released stress (when releasing the tension, the tension cannot be completely released, and part of the tension is retained to ensure that the product is in a flattened state and the length of the product after cutting does not change too much), which maximizes the avoidance of the phenomenon of arch-shaped rebound of the product to the middle due to the instantaneous release of tension at the moment when the cutting action is completed. In addition, the stress release method provided in the embodiment calculates the recovery deformation of the product 20 to be released stress, controls the first distance d1≤d of the product 20 to be released stress in the X direction, calculates the first deformation average, and judges whether the first deformation average is within the preset range. If yes, the current state of the product 20 to be released stress is maintained, and cutting is performed. The steps of calculating the first deformation average and judging whether the first deformation average is within the preset range can be used to determine whether the internal stress of the product 20 to be released stress is released to an appropriate range. Further, after using the stress release method provided in the embodiment, whether it is a thin Invar alloy material or a high-precision fine metal mask product, the stress is released before cutting, and the appropriate tensile stress can be maintained to avoid wrinkles in the product 20 to be released stress (thin Invar alloy material, FMM). After the stress is released, the yield of the material (cutting effect) is greatly improved.

[0086] In one embodiment, further comprising:

[0087] S05B, if the first deformation average is not within the preset range, further control the product 20 to be released stress to move a second distance d2 in the X direction ;

[0088] S06, acquire a fourth image of the product 20 to be released stress after moving the second distance, compare the second image and the fourth image, and calculate the second deformation average of the product 20 to be released stress. If the sum of the first deformation average and the second deformation average is within the preset range, the current state of the product 20 to be released stress is maintained, and cutting is performed.

[0089] In the embodiment, if the sum of the first deformation average and the second deformation average is not within the preset range, the product 20 to be released stress is further controlled to move an nth distance d n in the X direction until the internal stress of the product 20 to be released stress is released to an appropriate range, and then the current state of the product 20 to be released stress is maintained, and cutting is performed.

[0090] In one embodiment, if > the product 20 to be released stress needs to be detected whether it has been damaged, if not, the product 20 to be released stress is stretched to a tensile stress state, and the tensile stress of the metal mask product is further released according to the steps S01-S05A and S05B described above, so that the metal mask product does not produce arch-shaped rebound after cutting.

[0091] In one embodiment, in S03, the step of determining whether there is a difference between the first image and the second image comprises:

[0092] The first image and the second image are respectively divided into a plurality of pixel regions, and each pixel region includes a plurality of holes.

[0093] By comparing whether there is a difference between the pixel regions at the same position in the first image and the second image, it is determined whether there is a difference between the first image and the second image. If there is a difference between the pixel regions at the same position in the first image and the second image, there is a difference between the first image and the second image.

[0094] If the number of holes included in the pixel regions at the same position is different, or if the size of at least one hole included in the pixel regions at the same position is different, the pixel regions at the same position are different.

[0095] In this embodiment, a specific determination method for determining whether there is a difference between the first image and the second image by comparing the first image and the second image is provided. The determination method is simple and effective, can quickly identify whether there is a difference, and is conducive to improving the efficiency in the determination process.

[0096] In one embodiment, in S03, the step of calculating the recovery strain d of the stress-released product 20 in the X direction after stress release comprises:

[0097] S10, converting the metal mask plate product with a high-density micro-hole structure into an equivalent homogeneous structure, wherein the conversion process includes calculating the porosity of the metal mask plate, and correcting the equivalent material parameters of the metal mask plate in combination with the porosity.

[0098] S20, creating a plane shell model, obtaining equivalent material parameters, and performing mesh division according to linear quadrilateral shell elements.

[0099] S30, determining the type of boundary condition, obtaining the displacement field of each pixel point as the initial displacement input by comparing the first image and the second image, and setting all degrees of freedom of the X=0 end of the constrained metal mask plate to be 0.

[0100] S40, setting a solver and performing solving calculation, and outputting the calculation result as the full-field X-direction normal stress. The analysis type of the solver is static linear analysis, and the convergence control is the default residual tolerance. The default residual tolerance is less than 10 −6 .

[0101] S50, combining the full-field X-direction normal stress calculated in S40 to calculate the X-direction recovery strain d.

[0102] In this embodiment, the specific method steps of calculating the recovery deformation variable d in the X direction by the finite element model are refined, and the microscopic stress change is quantified and extracted as the intuitive size change. In this embodiment, through strict theoretical derivation combined with experimental feedback, high-precision stress balance control can be realized without changing the hole structure of the stress-released product 20 (metal mask plate), and the application error can be controlled within ±2%. If the application error is >5%, the equivalent material parameters need to be recalibrated.

[0103] In one embodiment, please refer to Figure 3 The detailed structure diagram of the provided stress-released product 20 is shown in S10. The porosity of the metal mask plate is , and the porosity is calculated by the following formula (1) to formula (5) .

[0104] Formula (1);

[0105] Formula (2);

[0106] Formula (3);

[0107] Formula (4);

[0108] Formula (5);

[0109] Wherein, D is the diameter of the equivalent hole in the metal mask plate, m is the diameter of the first hole, n is the diameter of the second hole, m1 is the depth of the first hole, n1 is the depth of the second hole, L is the length of the metal mask plate, W is the width of the metal mask plate, TH is the thickness of the metal mask plate, V1 is the single hole volume of the equivalent hole, N u is the number of equivalent holes on the metal mask plate, V2 is the total hole volume of the metal mask plate, and V is the total volume of the material of the metal mask plate.

[0110] The equivalent material parameters of the metal mask plate are , and the equivalent material parameters are calculated by the following formula (6) .

[0111] Formula (6);

[0112] Wherein, is the elastic modulus of the metal mask plate.

[0113] As Figure 3As shown, the product 20 to be released stress (metal mask) includes a first surface 21 and a second surface 22. The first surface 21 has a first hole 211 (small hole), and the second surface 22 has a second hole 221 (large hole). The metal mask has a high-density micro-hole structure. The high-density micro-hole structure in the metal mask can be converted into an equivalent homogeneous material to simplify the finite element calculation process. In one specific embodiment, the length L of the metal mask is 1226 mm, the width W is 75 mm, the thickness TH is 0.025 mm, the diameter of the first hole is m = 48 μm, the diameter of the second hole is n = 52 μm, the depth of the first hole is m1 = 3 μm, the depth of the second hole is n1 = 22 μm, and the equivalent hole number is about 40 million. It is calculated that the diameter of the equivalent hole in the metal mask is D = 51.52 μm, and the porosity of the metal mask is 9.23%. The base material of the metal mask is nickel-iron alloy, and the elastic modulus , .

[0114] In one embodiment, the full-field X-direction normal stress calculated in S40 is , the full-field X-direction strain size is , and the following formula (7) is satisfied:

[0115] Formula (7);

[0116] In S50, the X-direction recovery deformation amount d is calculated using the following formula (8):

[0117] Formula (8);

[0118] is the sum of the full-field X-direction normal stresses, is the sum of the full-field X-direction strain distances.

[0119] In the above specific embodiment, it is calculated that = 5.89 mm.

[0120] In this embodiment, it is assumed that the maximum strain region is continuous (such as uniform stretching, continuous stretching). The recovery deformation amount d of the product 20 to be released stress in the X direction is the cumulative deformation amount of the entire product 20 to be released stress. In other embodiments, the metal mask can also be divided into multiple intermediate regions and multiple peripheral regions.

[0121] The embodiments provided in the application can identify the stress of each metal mask in the cutting station, determine the recovery deformation according to the stress, confirm the preset range of the average deformation value in combination with the recovery deformation, and when the stress is adjusted, if the average deformation value is in the preset range, it is considered that the internal stress of the metal mask to be released has been properly released, and the cutting work can be performed, avoiding the phenomenon of arch bridge caused by the rebound of the product to the middle due to the instantaneous release of tension at the moment when the cutting action is completed.

[0122] In one embodiment, the recovery deformation of the product 20 to be released in the X direction is 3.5mm-6.0mm. The sum of the movement distance of the product 20 to be released in the X direction is in the numerical range of 1.5mm-4.5mm.

[0123] In other embodiments, the length L of the metal mask can also be 850mm, 1080mm, 1200mm, 1226mm, 1290mm, etc. The width W can also be 70mm, 75mm, 85mm, 150mm, 220mm, 310mm, etc. The thickness TH can be set to 0.020mm, 0.025mm, 0.030mm, etc.

[0124] Please refer to Figure 4 The application also provides a stress release system for a metal mask, which is applied to the stress release of the metal mask before cutting. In one embodiment, the product 20 to be released is fixed to the product support frame 10, and the product 20 to be released is a metal mask in a stretched state.

[0125] The stress release system for the metal mask at least includes a controller, an image shooting assembly, a motor driving assembly, and a monitoring device, and the controller is signal connected with the image shooting assembly, the motor driving assembly, and the monitoring device. The stress release system for the metal mask is suitable for the stress release method of the metal mask in any of the above embodiments.

[0126] The image shooting assembly is configured to shoot the image information of the standard product and the product 20 to be released. The image shooting assembly is used to shoot the first image of the standard product and the second image, the third image, the fourth image, or more images of the product 20 to be released. The image shooting assembly can be set as a high-definition camera.

[0127] The motor driving assembly is configured to drive the product 20 to be released to move along the X direction on the product support frame 10. For example, the loosening of the movable carrier 12 (Ti strip) can be realized through the adjustable fixing part 13, the fixing screw or other structural parts, so that the movable carrier 12 (Ti strip) can be gathered to the middle of the product along the X direction to release part of the tensile stress (tensile stress).

[0128] ​The monitoring device is configured to monitor the moving distance of the stress-released product 20 in the X direction. In some embodiments, the stress-released product 20 is moved once in the X direction to release part of the tensile stress; in other embodiments, the stress-released product 20 is moved multiple times in the X direction to release part of the tensile stress.

[0129] The controller is configured to compare the image information of the standard product and the stress-released product 20, and determine whether there is a difference. In this step, the step of comparing whether there is a difference can not be operated, and the next step of calculation is performed after comparing the difference.

[0130] The controller is configured to calculate the recovery deformation amount of the stress-released product 20 in the X direction after stress release The specific calculation method has been specified in the above embodiments, and will not be repeated here. The controller is configured to calculate the average deformation amount of the stress-released product 20. The controller is configured to determine whether the average deformation amount is within a predetermined range, and if the average deformation amount is within the predetermined range, the current state of the stress-released product 20 is maintained, and cutting is performed.

[0131] In this embodiment, before the cutting process starts, the stress-released product 20 is released to a certain extent, which can maximize the avoidance of the phenomenon of arch-shaped rebound of the product to the middle due to the instantaneous release of the tension at the moment when the cutting action is completed. The recovery deformation amount of the stress-released product 20 is calculated, and the stress-released product 20 is moved in the X direction by a first distance d1≤d, the first average deformation amount is calculated, and it is determined whether the first average deformation amount is within a predetermined range, and if so, the current state of the stress-released product 20 is maintained, and cutting is performed. The above steps can be used to determine whether the internal stress of the stress-released product 20 is released to a suitable range. The above stress release method releases the stress before cutting, can maintain a suitable tensile stress, avoid wrinkles in the stress-released product 20, and greatly improve the yield of the material after the stress is released.

[0132] In one embodiment, the product support frame 10 includes a support frame 11, a guide rail 111, a movable carrier 12, and an adjustable fixing member 13.

[0133] The support frame 11 is parallel to the stress-released product 20 and is arranged to extend in the X direction. The support frame 11 includes at least two support bars arranged at intervals, and the support bars have guide rails 111.

[0134] The guide rail 111 is arranged on the support frame 11. The guide rail 111 can be arranged on part of the support frame 11. The specific area where the guide rail 111 is arranged can be set in combination with the size of the recovery deformation amount.

[0135] The movable carrier 12 is used to carry the product 20 to be released stress and can slide on the guide rail 111. The movable carrier 12 is movably arranged on the support strip and can move along the X direction on the guide rail 111. The metal mask product can be adhered to the movable carrier 12 by glue. The material of the movable carrier 12 can be Ti. The long side of the metal mask is arranged in parallel with the long side of the support strip. The wide side of the metal mask is parallel to the extension direction of the length of the movable carrier 12.

[0136] The adjustable fixing member 13 is used to fix the movable carrier 12 on the guide rail 111 to limit the movement of the product 20 to be released stress in the X direction. The adjustable fixing member 13 (fixing screw) can move up and down along the Z direction and is used to release the internal stress of the metal mask sample. The adjustable fixing member 13 can be a fixing screw and can be manually or mechanically loosened.

[0137] In the embodiment, the metal mask product to be released stress is placed on the product support frame 10 and flows from the previous station. Before the cutting process starts, the metal mask product to be released stress placed on the product support frame 10 is released stress.

[0138] In one embodiment, the product support frame 10 further comprises a limiting member 14 used to limit the recovery distance of the product 20 to be released stress in the X direction and can slide on the guide rail 111. The limiting member 14 can be a movable stop piece arranged on the guide rail 111 to limit the recovery distance of the movable carrier 12. The recovery distance of the movable carrier 12 is limited to avoid that the recovery distance of the movable carrier 12 is too large, which causes the product 20 to be released stress to recover too much and needs to be flattened again, thereby prolonging the processing time.

[0139] In the prior art, the product is not tension released before the cutting process starts, which causes the product to shrink to the middle and form an arch bridge-shaped rebound during the cutting process. In the above-mentioned embodiments of the present application, the tightness of the adjustable fixing member 13 is adjusted before the cutting process starts. The movable carrier 12 can move the product 20 to be released stress to the center position of the product by a certain distance under the tension of the tension of the product 20 to be released stress, so as to release the tension and avoid the product to rebound to the middle and form an arch bridge-shaped rebound phenomenon when the cutting action is completed.

[0140] Please refer to Figure 5aFig. 1 is a schematic diagram of a product after cutting of a metal mask in the prior art, in which a serious arch bridge-like springback and two slight arch bridge-like springbacks can be seen. In actual work, there are more serious arch bridge-like springback phenomena. In one specific embodiment of the present application, a stress release system for a metal mask uses the stress release method for a metal mask before cutting provided in any one of the above embodiments to release the stress of the product 20 before the cutting process. The stress release system for the metal mask includes a controller, an image capturing assembly, a motor driving assembly, a monitoring device, and a product support frame 10. The product support frame 10 includes a wooden support frame 11, guide rails 111 provided on part of the support frame 11, a Ti strip with a length longer than the width of the metal mask as a movable carrier 12, a fixed screw as an adjustable fixing member 13, and a movable stop piece as a limiting member 14. When it is monitored (the specific monitoring / computing method is calculated by the stress release method in the above embodiments) that the metal mask in the stretched state needs to release stress, the adjustable fixing member 13 is loosened by manual or machine operation, the movable carrier 12 can move from both sides to the middle along the X direction, and the limiting member 14 is limited and blocked at the preset position, so that the movable carrier 12 (Ti strip) moves about 3 mm to the center position of the product, releases a certain degree of tension (when releasing tension, part of the tension should be retained to ensure that the product is in a flat state and the length of the product after cutting does not change too much), and avoids the arch bridge-like springback phenomenon caused by the instantaneous release of tension when the cutting action is completed. As shown in Fig. 2, the product after releasing stress is cut, and the cut product does not have the arch bridge-like springback phenomenon. Figure 5b

[0141] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.​

Claims

1. A stress release method of a metal mask, applied to stress release before cutting of a metal mask, characterized by, The method comprises the following steps: S01, obtaining a first image of a standard product; S02, obtaining a second image of a stress-released product arranged on a product support frame, the stress-released product being a metal mask in a stretched state; S03, comparing the first image and the second image, and if there is a difference, calculating a recovery deformation variable d of the stress-released product in the X direction after the stress is completely released, the step of calculating the recovery deformation variable d comprising: S10, converting the metal mask product with a high-density micro-porous structure into an equivalent homogeneous structure, wherein the conversion process comprises calculating the porosity of the metal mask, and correcting the equivalent material parameters of the metal mask in combination with the porosity; S20, creating a plane shell model, obtaining the equivalent material parameters, and performing mesh division according to linear quadrilateral shell elements; S30, determining the boundary condition type, obtaining the displacement field of each pixel point as the initial displacement input by comparing the first image and the second image, and setting all degrees of freedom of the X=0 end of the constrained metal mask as 0; S40, setting a solver, and performing a solving calculation, and outputting a calculation result as a full-field X-direction normal stress; an analysis type of the solver is static linear analysis, and a convergence control is a default residual tolerance; the default residual tolerance is less than 10 -6 ; S50, calculating the X-direction recovery deformation variable d in combination with the full-field X-direction normal stress calculated in S40; S04, controlling the first distance d1 of the stress-released product moving in the X direction, and d1≤d; S05A, obtaining a third image of the stress-released product after moving the first distance, comparing the second image and the third image, and calculating a first deformation variable average of the stress-released product, if the first deformation variable average is within a preset range, maintaining the current state of the stress-released product, and cutting.

2. The method of stress release of a metal mask according to claim 1, wherein, Further comprising: S05B, if the first deformation variable average is not within the preset range, further controlling the second distance d2 of the stress-released product moving in the X direction; S06, obtaining a fourth image of the stress-released product after moving the second distance, comparing the second image and the fourth image, and calculating a second deformation variable average of the stress-released product, if the sum of the first deformation variable average and the second deformation variable average is within the preset range, maintaining the current state of the stress-released product, and cutting.

3. The method of stress release of a metal mask according to claim 2, wherein, In S03, the step of comparing the first image and the second image to determine whether there is a difference comprises: dividing the first image and the second image into a plurality of pixel regions respectively, each of the pixel regions comprising a plurality of holes; determining whether there is a difference between the first image and the second image by comparing whether there is a difference between the pixel regions at the same position in the first image and the second image; wherein if there is a difference between the pixel regions at the same position in the first image and the second image, there is a difference between the first image and the second image; if there is a difference in the number of holes included in the pixel regions at the same position, or if there is a difference in the size of at least one hole included in the pixel regions at the same position, there is a difference between the pixel regions at the same position.

4. The method of stress release of a metal mask according to claim 2, wherein In S10, the porosity of the metal mask is calculated by the following equations (1) - (5) : Equation (1); Formula (2); Formula (3); Equation (4); Formula (5); Wherein, D is the diameter of the equivalent hole in the metal mask, m is the diameter of the first hole, n is the diameter of the second hole, m1 is the depth of the first hole, n1 is the depth of the second hole, L is the length of the metal mask, W is the width of the metal mask, TH is the thickness of the metal mask, V1 is the single hole volume of the equivalent hole, N u is the number of equivalent holes on the metal mask, V2 is the total hole volume of the metal mask, and V is the total volume of the material of the metal mask. The equivalent material parameters of the metal mask are The equivalent material parameters are calculated by the following equation (6) : Formula (6): wherein E is the modulus of elasticity of the metal mask.

5. The method of stress release of a metal mask according to claim 4, wherein, The full-field X-direction normal stress calculated in S40 is The full-field X-direction strain size is and satisfies the following formula (7): Formula (7): In S50, the X-direction recovery deformation variable d is calculated by using the following formula (8): Formula (8): is the sum of the normal stresses in the X direction over the entire field, is the maximum strain in the X direction over the entire field.

6. The stress release method of a metal mask according to any one of claims 2 to 5, characterized in that, the recovery deformation amount in the x direction of the stress-released product is 3.5 mm - 5.5 mm; The sum of the moving distances of the stress-releasing product in the X direction is in the range of 1.5mm-3.5mm.

7. A stress release system for a metal mask, applied to stress release before cutting of the metal mask, characterized in that, The stress-releasing product is fixed on the product support frame, and the stress-releasing product is a metal mask in a stretched state. The stress-releasing system of the metal mask comprises a controller, an image shooting assembly, a motor driving assembly, and a monitoring device, the controller is signal connected with the image shooting assembly, the motor driving assembly, and the monitoring device respectively, and the stress-releasing system of the metal mask is applicable to the stress-releasing method of the metal mask in any one of claims 1-6. The image shooting assembly is configured to shoot image information of the standard product and the stress-releasing product. The motor driving assembly is configured to drive the stress-releasing product to move in the X direction on the product support frame. The monitoring device is configured to monitor the moving distance of the stress-releasing product in the X direction. The controller is configured to compare the shot image information of the standard product and the stress-releasing product, and determine whether there is a difference. The controller is configured to calculate the recovery deformation of the product to be released in the X direction after stress release ; The controller is configured to calculate the average deformation value of the stress-releasing product. The controller is configured to determine whether the average deformation value is in a preset range, and if the average deformation value is in the preset range, the current state of the stress-releasing product is maintained, and cutting is performed.

8. The stress release system for a metal mask according to claim 7, wherein, The product support frame comprises a support frame, a guide rail, a movable carrier, and an adjustable fixing member. The support frame is parallel to the stress-releasing product and extends in the X direction. The guide rail is arranged on the support frame. The movable carrier is used to carry the stress-releasing product and can slide on the guide rail. The adjustable fixing member is used to fix the movable carrier on the guide rail to limit the movement of the stress-releasing product in the X direction.

9. The stress release system for a metal mask according to claim 8, wherein, The product support frame further comprises a limiting member used to limit the recovery distance of the stress-releasing product in the X direction and can slide on the guide rail.

Images