Optical film flat winding process, apparatus, system and computer readable storage medium thereof

Abstract

The application discloses an optical film flattening and winding process, device, system and computer readable storage medium, and continuous winding is performed on the optical film after extrusion molding, stretching, coating and drying; in the winding process, the optical film is expanded through an expansion roller; then the expanded optical film is sent to a swing winding device, so that the thickness of the optical film in the winding direction is dispersed along the horizontal direction; finally, the dispersed optical film is wound by a winding roller, and the tension of the winding roller is controlled in a decreasing mode according to the winding length. The application can make the film be expanded and dispersed horizontally after being wrinkled, and then be wound in a decreasing mode according to the tension of the winding length, so that the film winding wrinkles can be reduced, the uneven places of the film thickness are relatively dispersed, and the bulges are not concentrated in one place, and the overall film winding appearance is more uniform and flat.

Description

Technical Field

[0001] This invention belongs to the field of optical thin film production technology. Specifically, it is an optical thin film flattening and winding process, apparatus, system, and computer-readable storage medium. Background Technology

[0002] As electronic products such as mobile phones, televisions, and laptops become increasingly thinner, the optical compensation films used in their displays are also required to be thinner. The thickness has decreased from 100-300 μm to 5-40 μm. As the film thins, the difficulty of winding it up increases exponentially. Because most optical films are manufactured using extrusion molding, stretching, and coating processes, inconsistencies in thickness are inevitable along the width of the roll. During winding, thicker areas accumulate due to repeated layering, resulting in a "canned" appearance. Thinner areas collapse due to gaps between layers, ultimately leading to defects in the rolled-up appearance or even rendering the film unusable.

[0003] Currently, in film winding processes, the common methods to solve wrinkles during winding are to use extension rollers or change the winding tension. For example, the extension roller described in CN203998315U for lithium battery separators has a straight cylindrical shape with a symmetrical cylindrical surface. A single spiral groove is recessed along the cylindrical surface from the symmetrical plane to each of the two axial ends of the roller. These two single spiral grooves are arranged symmetrically along the aforementioned symmetrical plane. In use, the extension roller has a micro-tension expansion function relative to the lithium battery separator, while also ensuring the surface flatness of the separator during winding. Regarding winding tension adjustment, as described in CN110963334A, the winding tension is adjusted according to the roll diameter during battery separator winding. That is, as the roll diameter increases, the winding tension gradually increases, making the winding mechanism more stable and significantly reducing problems such as tube bottom wrinkles, ridges, creases, and slippage. For example, CN115744436A describes a method that reduces the tension applied to the film before winding based on the length of the wound film, in order to counteract the phenomenon of the outer film "clamping" the inner film caused by the increase in the film roll diameter, so that the tension between the inner and outer layers of the film is consistent, thereby solving the problem of wrinkles or bubble deformation on the outer film surface.

[0004] It can be seen that the existing technologies for solving the wrinkles caused by winding are all based on the adjustment of the tension balance of the film during the winding process. Therefore, it is possible to adjust according to the tension change during the winding process of the film. However, in the winding process of optical films, the uneven thickness of the film in the width direction is often difficult to predict in the subsequent winding process. Moreover, the film thickness gradually decreases, which makes it unsatisfactory to adjust the winding quality of the optical film by only changing the tension during the winding process. Summary of the Invention

[0005] The purpose of this invention is to provide a flattening and winding process for optical thin films. During the winding process, the film undergoes wrinkle expansion and horizontal dispersion, and then is wound up with decreasing tension according to the winding length. This reduces wrinkles during film winding, relatively disperses areas of uneven film thickness, and prevents bulging from concentrating in one place, resulting in a more uniform and flattened overall appearance. To this end, this invention also provides a control device, system, and computer-readable storage medium for implementing the flattening and winding process, enabling automated control of the film winding procedure.

[0006] This invention is achieved through the following technical solution: an optical thin film flattening and winding process, which continuously winds up the optical thin film after extrusion molding, stretching, coating, and drying. The winding process is carried out according to the following steps:

[0007] I. The optical film is expanded using an expanding roller;

[0008] II. The expanded optical film is fed to the oscillating winding device, so that the thickness of the optical film in the winding direction is dispersed in the horizontal direction;

[0009] Ⅲ. The dispersed optical film is wound up by a take-up roller, and the tension F of the take-up roller is controlled to satisfy: F=120-20N, where N is 1, 2, 3, 4 or 5;

[0010] When the winding length L < 200m, N = 1;

[0011] When the winding length is controlled to be 200≤L<400m, N=2;

[0012] When the winding length is controlled to be 400≤L<600m, N=3;

[0013] When the winding length is controlled to be 600≤L<800m, N=4;

[0014] When controlling the winding length to be 800≤L<1000m, N=5.

[0015] The extending roller is a curved roller or a roller with outwardly extending grooves on its surface.

[0016] The curved roller is a curved roller with a curved arc in the middle, or a roller that is thick in the middle and thin at both ends, and the height h of the curved part of the curved roller satisfies: 2mm≤h≤30mm.

[0017] The swing winding device includes a connecting part, a swing roller for transporting the optical film, a rotatable swing shaft, and a hydraulic system. The swing roller is rotatably mounted on the connecting part, the swing shaft is set perpendicular to the optical film and connected to the connecting part, and the hydraulic system acts on the connecting part along the width direction of the optical film.

[0018] The connecting part, in conjunction with the hydraulic system and the rotating shaft, drives the swing roller to swing, and the swing amplitude of the swing roller is less than 5% of the width of the optical film.

[0019] The oscillation frequency of the oscillating roller is n, and its calculation formula is shown in the following equation:

[0020]

[0021] Where L is the winding length, v is the winding speed, and d is the thickness of the optical thin film.

[0022] An optical thin film flattening and winding control device includes an extension roller, a swing winding device, and a winding roller arranged sequentially. The swing winding device includes a connecting part, a swing roller, a rotatable swing shaft, and a hydraulic system. The swing roller is rotatably mounted on the connecting part. The swing shaft is set perpendicular to the optical thin film and connected to the connecting part. The hydraulic system acts on the connecting part along the width direction of the optical thin film. The connecting part, in conjunction with the hydraulic system and the swing shaft, drives the swing roller to swing, so that the thickness of the optical thin film in the winding direction is dispersed in the horizontal direction.

[0023] It also includes a swing control system and a tension control system.

[0024] The oscillation control system is used to control the hydraulic system during the winding of the optical film;

[0025] The tension control system is used to control the tension of the take-up roller based on the take-up length of the optical film.

[0026] An optical thin film flattening and winding system includes a storage device, a processor, and a computer program stored on the processor and running on the processor. When the processor executes the computer program, it implements the flattening and winding process as described above.

[0027] A computer-readable storage medium storing a computer program that, when executed by a processor, implements the flattening and winding process described above.

[0028] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0029] (1) The present invention introduces a swing winding device in the winding process of optical film. The hydraulic system applies a force in the width direction of the film to the connecting part, so that the connecting part swings under the cooperation of the swing shaft. This can disperse the thickness of the optical film in the winding direction along the horizontal direction, so as to improve the can-shaped pattern that occurs when the thickness is inconsistent in the width direction during the manufacturing of optical film.

[0030] (2) In the actual control process, as the winding length increases, the winding diameter gradually increases, and the tension of the winding roller will increase, causing the film to become taut. Therefore, in order to improve the winding quality, the present invention adopts a tension reduction method to wind up the optical film. Specifically, the winding tension of the winding roller is controlled according to the winding length. However, due to the influence of the flatness and thickness uniformity of the optical film itself, it is difficult to determine the winding length and winding tension of the optical film. Therefore, the present invention gives a specific relationship between the winding roller tension F and the winding length based on the characteristics of the optical film, thereby improving the winding quality of the optical film and meeting the appearance requirements after winding.

[0031] (3) The present invention uses an extension roller, a swing winding device, a winding roller, a swing control system and a tension control system to form a winding control device for optical films. It can improve the existing winding process by adding only the required components and control system. The interval between the extension roller and the swing winding device is not particularly required and can be used on site. The tension control system adjusts the tension of the winding roller according to the obtained winding length and obtains the winding tension through the pressure sensor in contact with the winding roller. The equipment modification cost is low and it is easy to automate.

[0032] In summary, this invention is specifically designed for the winding of optical films, solving the problem of inconsistent thickness of optical films in the width direction affecting winding. During the winding process of optical films, after continuous processing by the spreading roller and the swing roller, the film is wound in a tension-reducing manner according to the winding length, which makes the surface of the wound film flat without obvious protrusions or collapses. The difference between concave and convex peaks along the width direction of the whole roll of film is less than 2mm, and the difference between the thickness of the upper and lower parts of the core is less than 5mm. Attached Figure Description

[0033] Figure 1 This is a process flow diagram of the present invention.

[0034] Figure 2 This is a schematic diagram of the extension roller structure.

[0035] Figure 3 This is a schematic diagram of the oscillating winding device.

[0036] Figure 4 This is a picture of the rolled film after it was rewound in Example 5.

[0037] Figure 5 This is a picture of the film after it has been wound up, as shown in Comparative Example 1.

[0038] Figure 6 This is a picture of the film after it has been wound up, as shown in Comparative Example 2.

[0039] Figure 7 This is a picture of the film after it has been wound up, as shown in Comparative Example 3.

[0040] Among them, 1—extension roller, 2—oscillating winding device, 3—winding roller, 4—connecting part, 5—oscillating roller, 6—oscillating shaft, 7—hydraulic system, 8—bonding roller, 9—protective film, 10—support roller. Detailed Implementation

[0041] The invention's objective, technical solution, and beneficial effects will be further explained in detail below.

[0042] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the claimed invention. Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0043] This invention is a process for achieving flat winding of optical films using an extension roller 1, a swing winding device 2, and a winding roller 3. It aims to solve the problem of canned wrinkles that occur during winding of optical films due to inconsistent thickness in the width direction of the entire roll of film during the manufacturing process. At the same time, it can also reduce winding wrinkles, making the winding of optical films more uniform and flat, and avoiding appearance defects.

[0044] In existing technologies, using the extension roller 1 or adjusting the tension of the winding roller 3 are conventional methods to improve the quality of film winding, such as CN203998315U and CN115744436A. However, in practical implementation, since the flatness and thickness uniformity of the film itself are not considered, even with the use of the extension roller or adjustment of the winding tension, only the wrinkles generated during winding can be overcome, and canning patterns may still occur. In particular, in CN115744436A, the functional relationship f(x) between the film tension and the length of the wound film is determined based on a smooth curve of the tension value and the length of the wound film. Although this can solve the problem of wrinkles or bubble deformation on the outer film surface, the film tension value corresponding to the wound length changes curvilinearly. To achieve the ideal effect, in actual operation, the entire control must be adjusted using the obtained length of the wound film in real time and continuously. This requires a high degree of automation, and any problems will inevitably cause defects in the winding of the entire roll of film.

[0045] Based on the automation requirements of on-site film winding, this invention adds a swing control system and a tension control system to the swing winding device 2 and winding roller 3 in the winding process. During winding, only the swing control system needs to be activated to enable the hydraulic system 7 to work continuously and swing the swing roller 5. As the optical film passes through the swing roller 5 during winding, its thickness in the winding direction is dispersed horizontally. There are no restrictions on the number and spacing of the swing rollers 5, and they can be set up at any position as long as the on-site layout is met. The tension control system is used to control the tension of the winding roller 3 according to the winding length of the optical film. For example, the winding length of the optical film can be obtained from a length meter located at the winding machine, and the tension of the winding roller 3 at the corresponding length can be calculated. The tension is adjusted by controlling the rotation speed of the winding roller 3. Finally, the pressure sensor in contact with the winding roller 3 feeds back the tension of the winding roller 3 to the tension control system, thereby determining whether the tension adjustment has reached the preset data. This control method is simple, and the tension of the winding roller 3 does not change in different length ranges. Therefore, there is no need for continuous adjustment of the tension of the winding roller 3, making it easy to operate and achieve automated control.

[0046] The present invention will be further described in detail below with reference to embodiments, but the embodiments of the present invention are not limited thereto. In the present invention, "film" and "thin film" both refer to "optical thin film".

[0047] Example 1:

[0048] This embodiment is an optical thin film flattening and winding control device.

[0049] Adopting such Figure 1 The winding control device shown includes an extension roller 1, a swing winding device 2, and a winding roller 3 arranged in sequence.

[0050] The spreading roller 1 is used to spread out film wrinkles, reducing wrinkles during the film winding process. It can be a curved roller with a certain curvature in the middle, or a roller that is thicker in the middle and thinner at both ends, such as... Figure 2 The curved rollers shown in (a) and (c) have a better effect on expanding wrinkles when the height h of the curved portion of the roller satisfies 2mm ≤ h ≤ 30mm; alternatively, rollers with outwardly expanding textures can also be used, such as... Figure 2 The rollers shown in (b) and (d) are shown in the middle.

[0051] The oscillating winding device 2 provides a certain amplitude of oscillation, which allows the thickness of the transported optical film in the winding direction to be dispersed horizontally, avoiding the "canned roller" phenomenon. For example... Figure 3As shown, the oscillating winding device 2 includes a connecting part 4, an oscillating roller 5, a rotatable oscillating shaft 6, and a hydraulic system 7. There are two connecting parts 4, with an axially rotatable oscillating roller 5 horizontally positioned between them. The oscillating shaft 6 is perpendicular to the oscillating roller 5 and connected to the connecting part 4, and the oscillating shaft 6 is axially rotatable. The hydraulic system 7 acts on the connecting part 4 along the width direction of the optical film, and the connecting part 4, in conjunction with the hydraulic system 7 and the oscillating shaft 6, drives the oscillating roller 5 to oscillate. In use, the extension rod of the hydraulic system 7 applies a force to the connecting part 4 along the width direction of the optical film, and the connecting part 4, in conjunction with the oscillating shaft 6, drives the oscillating roller 5 to oscillate.

[0052] To facilitate automated control, this embodiment also includes a swing control system and a tension control system. The swing control system is connected to the hydraulic system 7. At the start of winding, the swing amplitude and frequency of the swing roller 5 are preset, and the swing control system is activated, causing the hydraulic system 7 to start. The swing roller 5 continues to swing according to preset conditions during the winding process. The tension control system is connected to a length measuring instrument, the winding roller 3, and a pressure sensor, etc. During winding, the tension of the winding roller 3 is controlled according to the winding length of the optical film.

[0053] Example 2:

[0054] This embodiment describes an optical thin film flattening and winding process.

[0055] This method is mainly for the continuous winding of optical films after extrusion molding, stretching, coating, and drying. It employs the control device described in Example 1. The film winding process is described in [reference needed]. Figure 1 .

[0056] First, the optical film is passed through the expansion roller 1. Because the expansion roller 1 has a bulge in the middle or has outward-expanding lines, the wrinkles on the surface of the film will be expanded to both sides until the surface is wrinkle-free.

[0057] Then, the expanded optical film passes through the bonding roller 8, and the protective film 9 is bonded to the surface of the optical film. After that, it passes through the support roller 10 and reaches the swing roller 5. The swing roller 5 rotates clockwise due to the friction of the film. At the same time, the telescopic rod of the hydraulic system 7 reciprocates to generate pressure. The entire device will rotate back and forth around the swing axis 6 at a small angle. This will cause the swing roller 5 to rotate back and forth around the swing axis 6 while rotating on its own axis, so that the wound film will have a certain amount of offset in the width direction.

[0058] In practice, limiting the swing amplitude and frequency of the swing roller 5 can better improve the canning effect on the film winding. Therefore, the swing amplitude of the swing roller 5 needs to be controlled to be less than 5% of the width of the optical film. When the swing frequency of the swing roller 5 is set to n, its calculation formula is as follows:

[0059]

[0060] Where L is the winding length, v is the winding speed, and d is the thickness of the optical thin film.

[0061] Finally, based on the length of the winding film, the winding is carried out by decreasing tension, and the tension F of the winding roller 3 is controlled to satisfy: F=120-20N, where N is 1, 2, 3, 4 or 5;

[0062] When the winding length L < 200m, N = 1;

[0063] When the winding length is controlled to be 200≤L<400m, N=2;

[0064] When the winding length is controlled to be 400≤L<600m, N=3;

[0065] When the winding length is controlled to be 600≤L<800m, N=4;

[0066] When controlling the winding length to be 800≤L<1000m, N=5.

[0067] As the winding length increases, the winding tension is gradually reduced to ensure relatively uniform tension when the roll radius increases. This results in a smooth film surface after winding, without obvious bumps or collapses, and without canning marks.

[0068] Example 3:

[0069] This embodiment is an optical thin film flattening and winding system. The system mainly consists of a storage device, a processor, and a computer program stored on the processor and running on the processor. When the processor executes the computer program, it implements the flattening and winding process as in Embodiment 1.

[0070] Example 4:

[0071] This embodiment is a computer-readable storage medium storing a computer program that, when executed by a processor, implements the flattening and winding process as described in Embodiment 1.

[0072] Examples 5 to 10 are specific implementations of the optical film flattening and winding process described in Example 2. In these specific implementations and operations, different extension rollers 1 from Example 1 and different oscillation control process conditions from Example 2 were used to wind up optical films (optical film width 1330 mm) obtained through the same manufacturing process, and the winding effect was evaluated. The results are shown in Table 1 below. Figure 4 This is an image of the roll film shown in Example 5.

[0073] Table 1

[0074]

[0075] Comparative Example 1:

[0076] This comparative example is a comparative experiment of Example 5, using the same structure as Example 5 for the extension roller 1, bonding roller 8, support roller 10 and take-up roller 3, and the tension control method of the take-up roller 3 is the same, but the use of the swing take-up device 2 is cancelled.

[0077] After winding up an optical thin film (1330 μm wide) obtained using the same manufacturing process, such as Figure 5 As shown, protrusions appear on the surface of the film roll. After measurement, the difference between the concave peaks and convex peaks along the width direction of the film roll is 6mm, and the difference between the thickness of the upper part and the lower part of the core is 11.5mm.

[0078] Comparative Example 2:

[0079] This comparative example is a comparative experiment of Example 7, using the same winding control device as Example 7, but the control conditions for swing amplitude and swing frequency are different.

[0080] Specifically, when winding up an optical film (1330 mm wide) obtained through the same manufacturing process, the oscillation amplitude is controlled at 32 mm, and the oscillation frequency is 55 times / min. For example... Figure 6 As shown, wrinkles appeared on the surface of the film after winding. According to the measurement, the difference between the concave peak and the convex peak of the film along the width direction is 3.5mm, and the difference between the thickness of the upper part and the lower part of the core is 5.5mm.

[0081] Comparative Example 3:

[0082] This comparative example is a comparative experiment of Example 9, using the same winding control device as Example 9, but with different tension control of the tension roller. Also, the protective film 9 was not applied during the winding process.

[0083] Specifically, when winding up an optical film (1330 μm wide) obtained through the same manufacturing process, the tension F of the winding roller 3 is controlled to satisfy:

[0084] When the winding length L < 200m, N = 80;

[0085] When the winding length is controlled to be 200≤L<400m, N=65;

[0086] When the winding length is controlled to be 400≤L<600m, N=55;

[0087] When the winding length is controlled to be 600≤L<800m, N=40;

[0088] When controlling the winding length to be 800≤L<1000m, N=30.

[0089] like Figure 7 As shown, after winding, the surface of the film is uneven and warped. Measurements show that the difference between the concave and convex peaks along the width direction of the film is 2.6 mm, and the difference between the thickness of the upper and lower parts of the core is 4.8 mm.

[0090] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. An optical thin film flattening and winding process, characterized in that: The optical film, after extrusion molding, stretching, coating, and drying, is continuously wound up. During the winding process, the following steps are performed: Ⅰ. The optical film is extended using an extension roller (1); II. The expanded optical film is fed to the oscillating winding device (2) so that the thickness of the optical film in the winding direction is dispersed in the horizontal direction. The swing winding device (2) includes a connecting part (4), a swing roller (5) for transporting the optical film, a rotatable swing shaft (6), and a hydraulic system (7). The swing roller (5) is rotatably mounted on the connecting part (4), the swing shaft (6) is set perpendicular to the optical film and connected to the connecting part (4), and the hydraulic system (7) acts on the connecting part (4) along the width direction of the optical film. The connecting part (4) works with the hydraulic system (7) and the rotating shaft to drive the swing roller (5) to swing. The swing amplitude of the swing roller (5) is less than 5% of the width of the optical film. The swing frequency of the swing roller (5) is n, and its calculation formula is as follows: Where L is the winding length, v is the winding speed, and d is the thickness of the optical thin film; Ⅲ. The dispersed optical film is wound up by the take-up roller (3), and the tension F of the take-up roller (3) is controlled to satisfy: F=120-20N, where N is 1, 2, 3, 4 or 5; When the winding length L < 200m, N = 1; When the winding length is controlled to be 200≤L<400m, N=2; When the winding length is controlled to be 400≤L<600m, N=3; When the winding length is controlled to be 600≤L<800m, N=4; When controlling the winding length to be 800≤L<1000m, N=5.

2. The process according to claim 1, characterized in that: The extended roller (1) is a curved roller or a roller with outwardly extending textures on its surface.

3. The process according to claim 2, characterized in that: The curved roller is a curved roller with a curved arc in the middle, or a roller that is thick in the middle and thin at both ends, and the height h of the curved part of the curved roller satisfies: 2mm≤h≤30mm.

4. An optical thin film flattening and winding control device, characterized in that: The device is used to perform the flattening and winding process as described in claim 1, and includes an extension roller (1), a swing winding device (2) and a winding roller (3) arranged in sequence. The swing winding device (2) includes a connecting part (4), a swing roller (5), a rotatable swing shaft (6) and a hydraulic system (7). The swing roller (5) is rotatably disposed on the connecting part (4). The swing shaft (6) is disposed perpendicular to the optical film and connected to the connecting part (4). The hydraulic system (7) acts on the connecting part (4) along the width direction of the optical film. The connecting part (4) cooperates with the hydraulic system (7) and the swing shaft (6) to drive the swing roller (5) to swing, so that the thickness of the optical film in the winding direction is dispersed in the horizontal direction.

5. The apparatus according to claim 4, characterized in that: It also includes a swing control system and a tension control system. The swing control system is used to control the hydraulic system (7) during the winding of the optical film; The tension control system is used to control the tension of the take-up roller (3) according to the take-up length of the optical film.

6. An optical thin film flattening and winding system, characterized in that: It includes a storage device, a processor, and a computer program stored on the processor and running thereon, wherein the processor executes the computer program to implement the flattening and winding process as described in any one of claims 1 to 3.

7. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program that, when executed by a processor, implements the flattening and winding process as described in any one of claims 1 to 3.

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