Light shielding film

Abstract

The utility model relates to a shading film which adopts a layered structure and comprises a base material layer, an anti-precipitation layer, a plurality of ink layers and a matte layer, and tight combination and performance synergy among the layers are realized through an optimized coating process. The multi-layer ink layer is formed by superposing two or more ink sub-layers, each layer is prepared from shading ink with high shading performance, and the thickness is controlled within the range of 2-4 microns. The matte layer serves as the outermost layer and endows the shading film with the characteristics of low gloss and reflection resistance. The anti-precipitation layer, the ink layer and the matte layer are symmetrically arranged on the base material layer and are formed in the same coating mode, so that tight combination between layers is ensured, and the overall structural stability and optical performance of the shading film are improved. According to the design scheme of the shading film, preparation of the high-performance shading film is achieved through a layered structure and an optimized coating process, the shading film is suitable for camera lenses, optical instruments and various precise optical assemblies, interference of external stray light is effectively prevented, and imaging definition and contrast are improved.

Description

Technical Field

[0001] The present application relates to the technical field of optical functional films, and in particular to a light-shielding film. Background Art

[0002] As a component of camera lenses, light-shielding films effectively block excess light, preventing stray light interference and improving image quality. Currently, the core technology in this field utilizes a single-sided, single-pass coating process to apply a matte black coating to the production of light-shielding films. While this single-pass coating process is mature, the resulting light-shielding films often suffer from insufficient optical density and numerous light-transmitting spots, which directly impacts lens image quality.

[0003] Furthermore, light-shielding films have stringent durability requirements. Currently, thin substrates on the market are generally single-sided with corona coating, making it difficult to meet performance requirements when double-sidedly coated. Furthermore, small molecules precipitate from the substrates under harsh conditions such as high temperature and high humidity, affecting product durability. Therefore, how to maintain the thin and lightweight nature of light-shielding films while resolving the conflict between optical density and gloss, and broadening the range of substrate options to meet the needs of a wider range of higher-standard applications, have become key challenges that need to be overcome in the current development of light-shielding film technology. There is an urgent need to explore new coating processes, optimize structures, and develop a more diverse range of substrate materials to meet the growing market and technical challenges. Utility Model Content

[0004] The purpose of the present application is to provide a light-shielding film that can achieve functional superposition by arranging different layers, reducing the difficulty of formulation, having higher optical density and fewer light-transmitting points, and having the functions of resisting precipitation and promoting adhesion, thereby improving the durability of the finished product. The light-shielding film of the present application includes a substrate layer, an anti-precipitation layer, an ink layer, and a matte layer;

[0005] The anti-precipitation layer is formed on both sides of the substrate layer;

[0006] The ink layer is formed on the anti-sedimentation layer on one side or both sides of the substrate layer;

[0007] The matte layer is located on the outermost side of the light-shielding film and is formed on the substrate layer and / or the ink layer;

[0008] The ink layer includes two or more ink sub-layers, and each of the ink sub-layers is formed of light-shielding ink.

[0009] In one embodiment, the thickness of the substrate layer is in the range of 4.5-23 μm, and the thickness of the matte layer is in the range of 2-4 μm.

[0010] In one embodiment, the thickness of the anti-sedimentation layer is in the range of 0.05-0.5 μm.

[0011] In one embodiment, the thickness of the ink layer is in the range of 2-4 μm.

[0012] In one embodiment, the ink layer includes at least an ink sublayer connected to the matte layer, which is a conductive ink layer.

[0013] In one embodiment, the ink sub-layers in the ink layer are formed by the same coating method.

[0014] In one embodiment, the anti-sedimentation layer, the ink layer and the matte layer are symmetrically arranged on the substrate layer.

[0015] In one embodiment, the anti-sedimentation layer, the ink layer, and the matte layer on both sides of the substrate layer are formed by the same coating method.

[0016] In one embodiment, the ink sub-layer includes carbon black particles.

[0017] In one embodiment, both sides of the substrate layer include at least two different ink sub-layers.

[0018] Compared with the prior art, this application has the following beneficial effects:

[0019] The light-shielding film of this application utilizes a multi-layer ink design, where the ink layer comprises two or more ink sub-layers, each composed of light-shielding ink, and these ink layers are superimposed on a substrate layer. Compared to the traditional single-sided coating method, this multiple-layer coating method can improve the optical density of the light-shielding film at the same thickness and effectively reduce the number of light-transmitting points (ensuring a high standard of no more than four light-transmitting points per square meter of film), thereby greatly improving the imaging quality of the lens.

[0020] To address the current problem of thin substrates being limited in specifications and difficult to meet specific needs, this application introduces an anti-sedimentation layer. Formed on both sides of the substrate layer, this layer not only effectively prevents the migration of small molecules in the substrate layer to the bonding interface, but also enhances the adhesion between the substrate layer and other layers, improving the durability and environmental adaptability of the finished product and extending its service life. The matte layer, as the outermost layer, ensures a low gloss effect without affecting the optical density contribution of the inner ink layer, reducing the difficulty of formula design and improving production efficiency.

[0021] In the light-shielding film design of the present application, the ink layer can be flexibly configured as the same or different ink sub-layers, and effective covering can be formed between the layers to further reduce the light transmission points. In addition, the anti-precipitation layer, ink layer and matte layer can be symmetrically arranged on the substrate layer and formed by the same coating method, which not only simplifies the production process, shortens the manufacturing process, but also ensures the consistency and stability of the product. By precisely controlling the thickness of each coating layer, such as the substrate layer thickness within the specific range of 4.5-23μm, the anti-precipitation layer thickness within the specific range of 0.05-0.5μm, and the ink layer thickness within the specific range of 2-4μm, and by using the same coating method, the thickness deviation of the coating on both sides of the substrate layer can be effectively reduced, and the flatness and dimensional accuracy of the light-shielding film can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic structural diagram of a light-shielding film in one embodiment of the present application;

[0023] Figure 2 It is a schematic structural diagram of a light-shielding film in another embodiment of the present application.

[0024] Explanation of reference numerals: 100, substrate layer; 200, anti-precipitation layer; 300, ink layer; 310, ink sub-layer; 400, matte layer. DETAILED DESCRIPTION

[0025] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. It will be understood that the specific embodiments described herein are only used to explain the present application, rather than to limit the present application. It should also be noted that, for ease of description, only some, rather than all, structures related to the present application are shown in the accompanying drawings. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0026] As used herein, the terms "comprise," "comprising," and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or elements is not limited to the listed steps or elements but may optionally include steps or elements not listed, or may optionally include other steps or elements inherent to the process, method, product, or apparatus.

[0027] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0028] Light-shielding films are widely used in camera lenses, optical instruments and various precision optical components. With their unique light-shielding properties, they can effectively prevent interference from external stray light, thereby improving imaging quality. With the increasing diversification of demands, the performance requirements for light-shielding films are becoming more and more stringent. Not only do they pursue higher optical concentrations and reduced light transmission points, but they also need to have good anti-precipitation capabilities to enhance product durability. At the same time, the trend of lightweight and high flatness also poses new challenges to the material selection and manufacturing process of light-shielding films. In this context, the traditional single-sided one-time coating process has gradually exposed its limitations, such as insufficient optical concentration, difficulty in controlling light transmission points, and difficulty in balancing glossiness and light-shielding performance. In order to meet the market's urgent demand for high-performance light-shielding films, this application proposes a new light-shielding film design scheme, which solves the problems existing in the existing technology through a layered structure and an optimized coating process, providing optical equipment with more reliable light-shielding performance. Next, the specific structure, technical features and beneficial effects of this innovative light-shielding film will be introduced in detail. Please refer to Figures 1 to 2 As shown, the light-shielding film in a preferred embodiment of the present application specifically includes a substrate layer 100, an anti-precipitation layer 200, an ink layer 300 and a matte layer 400, the anti-precipitation layer 200 is formed on both sides of the substrate layer 100, the ink layer 300 is formed on the anti-precipitation layer 200 on one side or both sides of the substrate layer 100, and the matte layer 400 is located on the outermost side of the light-shielding film, formed on the substrate layer 100 and / or the ink layer 300, wherein the ink layer 300 includes two or more ink sub-layers 310, and each of the ink sub-layers 310 is composed of light-shielding ink.

[0029] The light-shielding film of the present application is composed of the following core layers: a substrate layer 100, an anti-precipitation layer 200, a multi-layer ink layer 300 and a matte layer 400. The substrate layer 100 serves as the skeleton of the light-shielding film. The substrate layer 100 is made of a material with good mechanical properties and high dimensional stability, which provides strength support for the entire light-shielding film and ensures the firm adhesion of subsequent layers. The anti-precipitation layer 200 is arranged on both sides of the substrate layer 100, which can effectively prevent small molecules in the substrate from migrating to the surface, affecting the bonding strength of the interface, thereby enhancing the durability of the light-shielding film and avoiding performance degradation due to component migration. The multi-layer ink layer 300 is the key to achieving efficient light-shielding of the light-shielding film. The ink layer 300 is composed of two or more layers of ink sub-layers 310 stacked together. By precisely controlling the formula and thickness of each layer of ink, it can effectively reduce light transmission points, increase optical concentration, and improve imaging quality. The matte layer 400, as the outermost layer of the light-shielding film, imparts low gloss and anti-reflective properties to the light-shielding film, further reducing interference from external light while enhancing the wear resistance and scratch resistance of the light-shielding film. The specific material of the substrate layer 100 can be PET film or PI film.

[0030] Specifically, the thickness of the substrate layer 100 is in the range of 4.5-23 μm. A moderate thickness can meet the requirements of the application scenario. The thickness of the matte layer 400 is in the range of 2-4 μm, which can achieve a good diffuse reflection effect and ensure that the light-shielding film has a suitable glossiness.

[0031] Specifically, the thickness of the anti-precipitation layer 200 is in the range of 0.05-0.5μm. The main function of the anti-precipitation layer 200 is to prevent small molecules in the substrate layer 100 from migrating to other layers, thereby avoiding the resulting performance degradation. The thickness range of 0.05-0.5μm can not only form an effective barrier layer, but also ensure the stability of the interlayer bonding force, thereby maximizing the role of the anti-precipitation layer 200. An anti-precipitation layer 200 that is too thick may increase the cost, while reducing the thickness of other layers and affecting the optical properties of the light-shielding film. The thickness range of 0.05-0.5μm ensures the anti-precipitation effect while keeping the product at a suitable cost. The anti-precipitation layer 200 needs to be tightly combined with the substrate layer 100 and the ink layer 300 to ensure the structural stability of the light-shielding film. The appropriate thickness helps to form a good interlayer interface, enhance the adhesion between the layers, and improve the durability and reliability of the light-shielding film.

[0032] Specifically, the thickness of the ink layer 300 is in the range of 2-4 μm. The main function of the ink layer 300 is to absorb or block light to achieve the purpose of light shielding. The above thickness range ensures that the ink layer can fully exert its light shielding properties, effectively reduce light transmission points, and improve the optical density of the light shielding film.

[0033] Specifically, the ink layer 300 includes at least an ink sublayer 310 connected to the matte layer, and is made of conductive ink. With the increasing popularity of electronic devices, static electricity has become a significant factor affecting device performance and stability. During use, especially in mobile devices or moving parts, static electricity is easily generated due to friction or contact with charged objects. The conductive layer can quickly conduct away the generated static electricity, preventing damage to the device caused by static electricity accumulation.

[0034] Specifically, the ink sublayer 310 in the ink layer 300 is formed by the same coating method. The unified coating method simplifies the manufacturing process and reduces the additional steps and equipment introduced by changing the coating method. This not only reduces production costs, but also improves production efficiency and yield, which helps to improve the market competitiveness of the light-shielding film. The same coating method makes it easier to control the quality of the light-shielding film during the production process, because the coating process can be uniformly optimized and monitored, which helps to ensure that the performance and quality of each batch of light-shielding film remain highly consistent. The coating method is specifically carried out using a multi-color machine, which can coat the anti-precipitation layer 200, the ink layer 300 and the matte layer 400 on one side of the substrate layer 100 at one time. In order to meet the coating requirements of this application, the multi-color machine is selected to include at least four coating heads.

[0035] Specifically, the anti-precipitation layer 200, the ink layer 300 and the matte layer 400 are symmetrically arranged on both sides of the substrate layer 100. This design can reduce the bending, deformation or interlayer separation of the membrane caused by uneven interlayer stress, and improve the overall flatness and structural stability of the shading film.

[0036] Specifically, the anti-precipitation layer 200, the ink layer 300, and the matte layer 400 on both sides of the substrate layer 100 are formed using the same coating method. This unified coating method allows for precise control of the thickness and uniformity of each layer, ensuring the light-shielding film achieves optimal optical and mechanical properties, as well as adaptability to environmental conditions. For the ink layer 300, in particular, uniform thickness and distribution are crucial for ensuring both light-shielding effectiveness and image quality. Using the same coating method simplifies the manufacturing process, reduces the need for additional steps and equipment associated with changing coating methods, lowers production costs, and improves production efficiency and yield.

[0037] Specifically, the ink sublayer 310 includes carbon black particles. Carbon black particles can efficiently absorb visible light, thereby improving the light-shielding effect of the ink sublayer 310. This is crucial for optical devices that require high light-shielding performance, ensuring that the device can maintain clear imaging even in strong light environments. The carbon black particles in the conductive ink layer have a certain degree of conductivity. When evenly dispersed in the ink sublayer 310, they can form a conductive network, improving the conductivity of the ink layer 300. This is particularly important for optical devices that require electrostatic protection, as it can effectively prevent damage to the device caused by static electricity accumulation. In addition, the carbon black particles have excellent thermal stability and can maintain stable performance in high-temperature environments.

[0038] Specifically, the substrate layer 100 includes at least two different ink sub-layers 310 on either side. These different ink sub-layers 310 can utilize different light-shielding materials or formulations to achieve a superposition of different ink layer functions. For example, one layer can contain a high-light-shielding ink, while the other layer contains a conductive light-shielding ink, thereby achieving a higher optical density. The design of at least two different ink sub-layers 310 provides greater flexibility in the manufacturing process. Based on the functional requirements of each layer, the appropriate coating method, curing conditions, and post-processing process can be selected without adding additional structures, thereby achieving optimal integration and performance between the layers.

[0039] The technical solution of this application is further explained below in conjunction with specific implementation methods.

[0040] Example 1

[0041] Anti-precipitation coating: self-developed

[0042] Ink sublayer: APET-SH:SXN=100:4 (both produced by Dainichi Seika Chemical Co., Ltd.)

[0043] Matte layer: HF matte oil-4: HF varnish-1 = 4:1 (both produced by Dainichi Seika Chemical Co., Ltd.)

[0044] A 0.2 μm anti-exfoliation coating, three 1 μm ink sublayers, and a 3 μm matte layer were sequentially coated on one side of a 4.5 μm PET film (model: FT, Foshan DuPont Hongji Film Co., Ltd.). The same process was then performed on the other side of the PET film. After winding, the film was placed in an aging room for 24 hours.

[0045] Example 2

[0046] Anti-precipitation coating: self-developed

[0047] Ink sublayer: APET-SH:SXN=100:4 (both produced by Dainichi Seika Chemical Co., Ltd.)

[0048] Matte layer: HF matte oil-4: HF varnish-1 = 4:1 (both produced by Dainichi Seika Chemical Co., Ltd.)

[0049] A 0.2 μm anti-exfoliation coating, two 1.5 μm ink sub-layers, and a 3 μm matte layer were sequentially coated on one side of a 10 μm PET film (model: LBD, Foshan DuPont Hongji Film Co., Ltd.). The same process was then performed on the other side of the PET film. After winding, the film was placed in an aging room for 24 hours.

[0050] Example 3

[0051] Anti-precipitation coating: self-developed

[0052] Ink layer: APET-SH:SXN=100:4 (both produced by Dainichi Seika Chemical Co., Ltd.)

[0053] Matte layer: HF matte oil-4: HF varnish-1 = 4:1 (both produced by Dainichi Seika Chemical Co., Ltd.)

[0054] A 0.2μm anti-exfoliation coating, a 3μm ink layer, and a 3μm matte layer were sequentially applied to one side of a 23μm PET film (model: BH216, Nan Ya Plastics Co., Ltd.). The same process was then repeated on the other side of the PET film. The film was then rolled up and placed in a curing room for 24 hours.

[0055] Example 4

[0056] Anti-precipitation layer: self-developed

[0057] Ink sublayer 1: FFC covering black: SXN=100:4 (both produced by Dainichi Seika Chemical Co., Ltd.)

[0058] Ink sublayer 2: APET-SH:SXN=100:4 (both produced by Dainichi Seika Chemical Co., Ltd.)

[0059] Matte layer: HF matte oil-4: HF varnish-1 = 4:1 (both produced by Dainichi Seika Chemical Co., Ltd.)

[0060] A 0.2 μm anti-exfoliation coating, 1.5 μm ink sublayer 1 and 2, and a 3 μm matte layer were sequentially coated on one side of a 10 μm PET film (model: LBD, Foshan DuPont Hongji Film Co., Ltd.). The same process was then performed on the other side of the PET film. After winding, the film was placed in an aging room for 24 hours.

[0061] Comparative Example 1

[0062] No anti-precipitation coating is provided, and other conditions are the same as those in Example 3.

[0063] Test methods and evaluation

[0064] 1. Coating thickness

[0065] The thickness of the anti-precipitation coating was tested using a Smart SE ellipsometer from HORIBA, Japan; the ink layer and matte layer were tested using a digital micrometer (model: 293-100-10) from Mitutoyo, Japan.

[0066] 2. Optical density

[0067] The optical density is a value measured using an optical densitometer (TD-904: Gretag Macbeth Co., Ltd.) and a UV filter in accordance with JIS-K7651:1988.

[0068] 3. Durability

[0069] The sample was placed in a KSON constant temperature and humidity testing machine (model: THS-C4T-100) at a temperature of 85°C and a humidity of 85%. After 500 hours, the sample was taken out and tested with 3M600. If 5B was found in the test grid, it was marked as ○, and if it fell off, it was marked as △.

[0070] The relevant test results are shown in Table 1.

[0071] Table 1 Summary of test results of various embodiments

[0072]

[0073] It can be seen from the above test results that the shading film in the technical solution of the present application not only has higher shading performance, but also has better durability.

[0074] As can be seen from the above, the present application proposes a new light-shielding film design solution to solve the problems of insufficient optical concentration, difficulty in controlling the light transmission point, and difficulty in balancing the glossiness and light-shielding performance in the traditional single-sided one-time coating process. The light-shielding film is composed of a substrate layer, an anti-precipitation layer, a multi-layer ink layer and a matte layer. The substrate layer serves as the skeleton of the light-shielding film and is made of a material with high dimensional stability and good mechanical properties, such as a PET film or a PI film. The thickness is precisely controlled within the range of 4.5-23μm, giving the light-shielding film good mechanical properties. The anti-precipitation layer is symmetrically arranged on both sides of the substrate layer, with a thickness within the range of 0.05-0.5μm, which effectively prevents small molecules in the substrate layer from migrating to the surface, affecting the bonding strength of the interface and enhancing the durability of the light-shielding film. At the same time, the anti-precipitation layer is tightly combined with the substrate layer and the ink layer to ensure the structural stability of the light-shielding film. The multi-layer ink layer is key to achieving efficient light-shielding in light-shielding films. Composed of two or more superimposed ink sub-layers, each composed of light-shielding ink, the ink layer thickness is controlled within the 2-4μm range. By precisely controlling the formulation and thickness of each ink layer, light transmission points are effectively reduced and optical density is improved. The matte layer, the outermost layer of the light-shielding film, imparts low gloss and anti-reflective properties, further reducing interference from external light and improving image quality. It also effectively protects the internal layer structure, enhancing the film's abrasion and scratch resistance.

[0075] The light-shielding film of this application utilizes the same coating method to form the anti-precipitation layer, ink layer, and matte layer, ensuring uniform distribution of each layer on the substrate, tight interface bonding, and enhanced interlayer bonding. This symmetrical arrangement combined with the same coating method not only enhances the overall structural stability and optical performance of the light-shielding film, but also simplifies the manufacturing process, reduces production costs, and improves production efficiency and yield. The design of including at least two different ink sub-layers on both sides of the substrate layer further achieves the functional superposition of the different ink layers, enhancing the optical performance of the light-shielding film.

[0076] In summary, the light-shielding film design proposed in this application, through its layered structure and optimized coating process, addresses existing issues in the prior art, providing more reliable light-shielding performance for optical devices. This light-shielding film boasts high optical density, a low light transmittance, and excellent durability, making it suitable for use in camera lenses, optical instruments, and various precision optical components, effectively preventing interference from external stray light and improving image quality.

[0077] The above is only a specific implementation of the present application. Any other improvements made based on the concept of the present application are considered to be within the scope of protection of the present application.

Claims

1. A light-shielding film, characterized in that: It comprises a substrate layer (100), an anti-sedimentation layer (200), an ink layer (300) and a matte layer (400); The anti-sedimentation layer (200) is formed on both sides of the substrate layer (100); The ink layer (300) is formed on the anti-sedimentation layer (200) on one side or both sides of the substrate layer (100); The matte layer (400) is located on the outermost side of the light-shielding film and is formed on the substrate layer (100) and / or the ink layer (300); The ink layer (300) includes two or more ink sub-layers (310), and each of the ink sub-layers (310) is formed of light-shielding ink.

2. The light-shielding film according to claim 1, wherein The thickness of the substrate layer (100) is within the range of 4.5-23 μm, and the thickness of the matte layer (400) is within the range of 2-4 μm.

3. The light-shielding film according to claim 1, wherein The thickness of the anti-sedimentation layer (200) is in the range of 0.05-0.5 μm.

4. The light-shielding film according to claim 1, wherein The thickness of the ink layer (300) is in the range of 2-4 μm.

5. The light-shielding film according to claim 1, wherein The ink layer (300) includes at least one ink sublayer (310) which is a conductive ink layer, and the conductive ink layer is connected to the matte layer (400).

6. The light-shielding film according to claim 1, wherein The ink sublayers (310) in the ink layer (300) are formed by the same coating method.

7. The light-shielding film according to claim 1, wherein The anti-sedimentation layer (200), the ink layer (300) and the matte layer (400) are symmetrically arranged on the substrate layer (100).

8. The light-shielding film according to claim 7, wherein The anti-sedimentation layer (200), the ink layer (300) and the matte layer (400) on both sides of the substrate layer (100) are formed by the same coating method.

9. The light-shielding film according to claim 1, wherein The ink sublayer (310) includes carbon black particles.

10. The light-shielding film according to claim 1, wherein Both sides of the substrate layer (100) include at least two different ink sub-layers (310).

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