Film coating structure and preparation method thereof

Abstract

The invention discloses a coating structure and a preparation method thereof. The film coating structure comprises a base material and a film layer structure, the film layer structure is located on one side of the base material and comprises a loose layer, the loose layer comprises a plurality of columnar microstructures, the multiple microstructures are distributed in the direction perpendicular to the thickness of the base material, and an air gap is formed between every two adjacent microstructures. The preparation method comprises the following steps: providing a substrate; and forming a film layer structure on one side of the base material, wherein the film layer structure comprises a loose layer; wherein the loose layer comprises a plurality of columnar microstructures, the multiple microstructures are distributed in the direction perpendicular to the thickness of the base material, and an air gap is formed between every two adjacent microstructures.

Description

Technical Field

[0001] The embodiments of this application relate to the field of optical technology, and in particular to coating structures and their preparation methods. Background Technology

[0002] Anti-reflection (AR) films primarily function to reduce or eliminate reflected light from the surfaces of elements such as lenses, prisms, and plane mirrors, thereby increasing the amount of light transmitted through these elements. AR films are widely used in daily life, industry, astronomy, electronics, and other fields.

[0003] Currently, antireflective films are usually made of low-refractive-index materials. However, the refractive index of these materials is fixed, which limits the types of low-refractive-index materials available and the limitations of current processing technology, making it difficult to further reduce the reflectivity of antireflective films. Summary of the Invention

[0004] This application provides a coating structure and a method for preparing the same.

[0005] The first aspect of this application provides a coating structure, which includes a substrate and a film structure. The film structure is located on one side of the substrate and includes a porous layer. The porous layer includes a plurality of columnar microstructures distributed in a direction perpendicular to the thickness of the substrate, and there are air gaps between adjacent microstructures.

[0006] According to one embodiment of this application, the microstructure has a size of 10 nm to 500 nm in the direction perpendicular to the thickness of the substrate.

[0007] According to one embodiment of this application, the minimum size of the air gap in the direction perpendicular to the thickness of the substrate is 3 nm to 50 nm.

[0008] According to one embodiment of this application, the inherent refractive index n of the porous layer is... s L 2 The number of microstructures x in a porous layer with a square area, and the average size of x microstructures in the direction perpendicular to the thickness of the substrate. And the refractive index n0 of air satisfies:

[0009]

[0010] Where L is L 2 The side length of the projection of the loose layer with a square area onto a plane perpendicular to the thickness direction of the substrate, where x is an integer.

[0011] According to one embodiment of this application, the number x of microstructures, the average value... And the side length L satisfies:

[0012]

[0013] According to one embodiment of this application, the inherent refractive index n of the porous layer is... s satisfy:

[0014] 1.3≤n s ≤1.65.

[0015] According to one embodiment of this application, the film structure is an anti-reflective film.

[0016] According to one embodiment of this application, the maximum reflectivity of the coating structure is no greater than 0.3% in the 400nm to 720nm wavelength range.

[0017] According to one embodiment of this application, the material of the porous layer includes at least one of SiO2, Al2O3, TiO2 and MgF2.

[0018] According to one embodiment of this application, the porous layer is formed by a vapor deposition process.

[0019] According to one embodiment of this application, the film structure further includes a connecting layer located between the substrate and the porous layer.

[0020] According to one embodiment of this application, multiple interconnecting layers are stacked sequentially along the thickness direction of the substrate, and adjacent interconnecting layers are made of different materials.

[0021] According to one embodiment of this application, the material of the bonding layer includes at least one of Nb2O5, SiO2 and TiO2.

[0022] The method for preparing a coating structure according to the second aspect of this application includes: providing a substrate; and forming a film structure on one side of the substrate, the film structure including a porous layer; wherein the porous layer includes a plurality of columnar microstructures, the plurality of microstructures being distributed in a direction perpendicular to the thickness of the substrate, and air gaps being present between adjacent microstructures.

[0023] According to one embodiment of this application, forming a film structure on one side of a substrate includes: placing the substrate into a reaction chamber; and processing the film material in the reaction chamber using a vapor deposition process, and introducing a collision gas into the reaction chamber to deposit the film material on one side of the substrate to form a loose layer.

[0024] According to one embodiment of this application, the minimum size of the air gap in the direction perpendicular to the thickness of the substrate is negatively correlated with the deposition temperature of the vapor deposition process and the vacuum degree of the reaction chamber, respectively, and positively correlated with the amount of collision gas introduced.

[0025] According to one embodiment of this application, the deposition temperature T, the vacuum degree P of the reaction chamber, and the injection rate F of the collision gas in the vapor deposition process satisfy the following:

[0026]

[0027] According to one embodiment of this application, T is 20℃~400℃, P is 0.0001Pa~0.1Pa, and F is 1sccm~1000sccm.

[0028] According to one embodiment of this application, the collision gas includes at least one of an inert gas, an oxidizing gas, and an inactive gas.

[0029] According to one embodiment of this application, the material of the film includes at least one of SiO2, Al2O3, TiO2 and MgF2.

[0030] According to one embodiment of this application, before depositing to form a porous layer, forming a film structure further includes forming a bonding layer on one side of the substrate.

[0031] According to one embodiment of this application, the microstructure has a size of 10 nm to 500 nm in the direction perpendicular to the thickness of the substrate.

[0032] According to one embodiment of this application, the minimum size of the air gap in the direction perpendicular to the thickness of the substrate is 3 nm to 50 nm.

[0033] According to one embodiment of this application, the inherent refractive index n of the porous layer is... s L 2 The number of microstructures x in a porous layer with a square area, and the average size of x microstructures in the direction perpendicular to the thickness of the substrate. And the refractive index n0 of air satisfies:

[0034]

[0035] Where L is L 2 The side length of the projection of the loose layer with a square area onto a plane perpendicular to the thickness direction of the substrate, where x is an integer.

[0036] According to one embodiment of this application, the number x of microstructures, the average value... And the side length L satisfies:

[0037]

[0038] According to one embodiment of this application, the inherent refractive index n of the porous layer is... s satisfy:

[0039] 1.3≤ns ≤1.65.

[0040] According to one embodiment of this application, the film structure is an anti-reflective film.

[0041] According to one embodiment of this application, the maximum reflectivity of the coating structure is no greater than 0.3% in the 400nm to 720nm wavelength range.

[0042] The coating structure provided in this application provides a porous layer with air gaps. When light is reflected at the interface between the microstructure of the porous layer and the air gaps, destructive interference can occur between the reflected light rays. At the same time, the scattering of light within the air gaps increases, which can significantly reduce the refractive index of the porous layer, thereby further reducing the reflectivity of the entire film structure.

[0043] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this application, nor is it intended to limit the scope of this application. Other features of this application will become readily apparent from the following description. Attached Figure Description

[0044] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings. The drawings are provided for a better understanding of the invention and are not intended to limit the scope of the application. In the drawings:

[0045] Figure 1 This is a cross-sectional schematic diagram of the coating structure according to one embodiment of this application;

[0046] Figure 2 This is a cross-sectional schematic diagram of the coating structure according to another embodiment of this application;

[0047] Figure 3 This is a cross-sectional schematic diagram of the coating structure according to another embodiment of this application;

[0048] Figure 4 This is an enlarged schematic diagram of the microstructure according to one embodiment of this application;

[0049] Figure 5 These are top views of the microstructures according to different embodiments of this application;

[0050] Figure 6 This is a schematic diagram illustrating the principle of a method for preparing a coating structure according to one embodiment of this application;

[0051] Figure 7 This is a scanning electron microscope (SEM) top view image of the porous layer according to the embodiments of this application;

[0052] Figure 8 yes Figure 7 A magnified view of a portion of the image;

[0053] Figure 9 It is a scanning electron microscope (SEM) cross-sectional image of the porous layer according to the embodiments of this application;

[0054] Figure 10 yes Figure 9 A magnified view of a portion of the image;

[0055] Figure 11 This is a graph showing the variation of reflectivity of the coating structure in different optical bands according to Embodiment 1 of this application;

[0056] Figure 12 This is a graph showing the variation of reflectivity of the coating structure in different optical bands according to Embodiment 2 of this application; and

[0057] Figure 13 This is a graph showing the variation of reflectivity of the coating structure in different optical bands according to Embodiment 3 of this application.

[0058] Figure label:

[0059] 100. Substrate; 200. Film structure; 210. Porous layer; 211. Microstructure;

[0060] 212. Air gap; 220. Connecting layer; 221. First connecting layer;

[0061] 222. Second connecting layer; 223. Third connecting layer; 224. Fourth connecting layer;

[0062] 225. Fifth connecting layer; 300. Ion source generator; 400. Membrane material. Detailed Implementation

[0063] To better understand this application, various aspects of this application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are merely illustrative of exemplary embodiments of this application and are not intended to limit the scope of this application in any way. Throughout the specification, the same reference numerals refer to the same elements. The expression "and / or" includes any and all combinations of one or more of the associated listed items.

[0064] It should be noted that in this specification, the terms "first," "second," "third," etc., are used only to distinguish one feature from another and do not imply any limitation on the features, especially not any order of precedence.

[0065] In the accompanying drawings, the thickness, dimensions, and shapes of the parts have been slightly adjusted for ease of illustration. The drawings are for illustrative purposes only and are not drawn to scale. As used herein, the terms “approximately,” “about,” and similar terms are used as expressions of approximation, not as expressions of degree, and are intended to illustrate inherent deviations in measured or calculated values ​​that will be recognized by one of ordinary skill in the art.

[0066] It should also be understood that expressions such as "comprising," "including," "having," "containing," and / or "comprising" are open-ended rather than closed-ended expressions in this specification, indicating the presence of the stated features, elements, and / or components, but not excluding the presence of one or more other features, elements, components, and / or combinations thereof. Furthermore, when expressions such as "at least one of..." appear after a list of listed features, they modify the entire list of features, not just individual elements in the list. Additionally, when describing embodiments of this application, the word "may" is used to mean "one or more embodiments of this application." And the term "exemplary" is intended to refer to examples or illustrations.

[0067] Unless otherwise specified, all terms used herein (including engineering and technical terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. It should also be understood that, unless expressly stated herein, terms defined in common dictionaries shall be interpreted as having the meaning consistent with their meaning in the context of the relevant art, and not as having an idealized or overly formalized meaning.

[0068] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. Furthermore, unless explicitly limited or contradicted by the context, the specific steps included in the methods described in this application are not limited to the order in which they are described, but can be performed in any order or in parallel. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0069] Furthermore, in this application, the term "layer" refers to a portion of material comprising a region having thickness. A layer may extend over the entirety of a structure below or above, or may have a range smaller than that of the structure below or above. Additionally, a layer may be a region of a homogeneous or heterogeneous continuous structure with a thickness less than the thickness of the continuous structure. A layer may extend horizontally, vertically, and / or along an inclined surface. A layer may include multiple sublayers. Furthermore, in this application, the use of "connection" or "joint" may indicate direct or indirect contact between corresponding components, unless otherwise expressly defined or inferred from the context.

[0070] like Figures 1 to 4As shown, one embodiment of this application provides a coating structure, which includes a substrate 100 and a film structure 200. The film structure 200 is located on one side of the substrate 100 and includes a loose layer 210. The loose layer 210 includes a plurality of columnar microstructures 211. The plurality of microstructures 211 are distributed in a direction perpendicular to the thickness of the substrate 100, and there are air gaps 212 between adjacent microstructures 211.

[0071] Since the porous layer 210 in this embodiment includes multiple columnar microstructures 211, and there are air gaps 212 between adjacent microstructures 211, the presence of air gaps 212 makes the porous layer 210 more porous. This allows destructive interference to occur between reflected light rays when reflected at the interface between the microstructures 211 and the air gaps 212. Simultaneously, the scattering of light within the air gaps 212 increases, thereby significantly reducing the refractive index of the porous layer 210. For example, the refractive index of the porous layer 210 can be reduced to 1.1–1.45. Therefore, a further reduction in the reflectivity of the entire film structure 200 can be achieved.

[0072] It should be noted that the microstructure 211 in the embodiments of this application can be a nanoscale structure, and the microstructure 211 may not be a regular cylinder. For example Figure 5 As shown, the projected shape of the microstructure 211 on a plane perpendicular to the thickness direction of the substrate 100 can be, but is not limited to, a regular shape such as a circle, ellipse, rectangle, or pentagon, or other irregular shapes; this application does not limit this. Figures 7 to 10 As shown, when observing the porous layer 210 using a scanning electron microscope (SEM), the microstructure 211 can be observed to be roughly columnar at magnifications of 10,000 to 50,000 times. The top view of the microstructure 211 is similar to that of a circle, and the sidewalls of the microstructure 211 are not smooth curved surfaces but are uneven. Furthermore, as an example, the dimension of the microstructure 211 in the first direction is greater than or equal to the dimension of the microstructure 211 in the second direction. The first direction is perpendicular to the thickness direction of the substrate 100, and the second direction is parallel to the thickness direction of the substrate 100.

[0073] Furthermore, in this embodiment, the microstructure 211 can be formed by a vapor deposition process. During the vapor deposition process, a collision gas can be introduced into the reaction chamber to promote columnar growth of the film material on the surface of the substrate 100 to form the microstructure 211. The vapor deposition process can be, but is not limited to, electron beam evaporation (EBE), magnetron sputtering (MB), plasma-enhanced chemical vapor deposition (PECVD), physical vapor deposition (PVD), and atomic layer deposition (ALD). Taking electron beam evaporation as an example... Figure 6 As shown, a substrate 100 and a film 400 are placed in a reaction chamber, and an electron beam is emitted towards the film 400 using an electron gun. The electron beam strikes the film 400, converting the kinetic energy of the electrons into heat energy, causing the film 400 to evaporate and form film particles with a certain energy, which then propel towards the substrate 100. Simultaneously, an ion generator 300 ionizes the molecules of the colliding gas into charged ions, which then propel towards the substrate 100 within the reaction chamber. During the process of the film particles formed by the evaporation of the film 400 and the ions formed by the ionization of the colliding gas towards the substrate 100, frequent collisions occur, leading to a decrease in the kinetic energy of the film particles. Some of the film particles reaching the surface of the substrate 100 are reflected, while others are adsorbed onto the surface of the substrate 100. The adsorbed film particles then diffuse to suitable locations through surface diffusion. With continuous adsorption and diffusion, multiple film particles aggregate to form clusters. Because the kinetic energy of the film particles is reduced due to collisions, the energy of the clusters is insufficient for large-area horizontal diffusion, making the clusters more inclined to grow vertically and form columnar microstructures 211.

[0074] Therefore, the porosity of the porous layer 210 can be altered by adjusting the flow rate of the collision gas, the deposition temperature, and the vacuum level of the reaction chamber, which in turn changes the size and number of the microstructures 211 and the air gaps 212. Furthermore, the mechanical strength and cohesion of the porous layer 210 can be optimized and improved during its formation using an additional ion source generator or plasma assistance. For example, a directional plasma fluid can be released via an ion source generator to continuously bombard the porous layer 210 with plasma during its growth.

[0075] As an example, such as Figure 4 and Figure 8As shown, the dimension D of the microstructure 211 in the direction perpendicular to the thickness of the substrate 100 can be from 10 nm to 500 nm. As mentioned above, the projected shape of the microstructure 211 on the plane perpendicular to the thickness direction of the substrate 100 can be, but is not limited to, a regular shape such as a circle, ellipse, rectangle, or pentagon, or other irregular shapes, thus... Figure 5 As shown, the dimension D of microstructure 211 generally refers to the projection of microstructure 211, that is, the diameter of the circumcircle of the cross-section of microstructure 211.

[0076] For example, the dimension D of the microstructure 211 in the direction perpendicular to the thickness of the substrate 100 is 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, or 450 nm. As an example, at least two of the multiple microstructures 211 have different dimensions D in the direction perpendicular to the thickness of the substrate 100.

[0077] As an example, the minimum dimension C of the air gap 212 in the direction perpendicular to the thickness of the substrate 100 is 3 nm to 50 nm. For example, the minimum dimension C of the air gap 212 in the direction perpendicular to the thickness of the substrate 100 is 10 nm, 20 nm, 30 nm, or 40 nm. The larger the air gap 212 between adjacent microstructures 211, the more porous the porous layer 210, and consequently, the lower the density and refractive index of the porous layer 210. Based on this, by limiting the minimum dimension C of the air gap 212 in the direction perpendicular to the thickness of the substrate 100 to the above range, the refractive index of the porous layer 210 can be reduced, the temperature and humidity resistance of the porous layer 210 can be improved, and the strength of the porous layer 210 can be guaranteed.

[0078] In some embodiments, the inherent refractive index n of the porous layer 210 s L 2 The number x of microstructures 211 in the porous layer 210 with a square area, and the average size of x microstructures 211 in the direction perpendicular to the thickness of the substrate 100. And the refractive index n0 of air satisfies:

[0079]

[0080] Where L is L 2 The side length of the projection of the loose layer 210 with a square area onto a plane perpendicular to the thickness direction of the substrate 100, where x is an integer.

[0081] like Figure 4As shown, a section is cut at any position of the porous layer 210. The projection of the cut porous layer 210 onto a plane perpendicular to the thickness direction of the substrate 100 is a square with side length L. In other words, the top view of the cut porous layer 210 is a square with side length L. x represents the number of microstructures 211 in the cut porous layer 210, and the average value is... Let be the average value of the size D of x microstructures 211. The number of microstructures 211 x, the size D of the microstructures 211, and the side length L of the cut loose layer 210 can all be measured by SEM observation. As an example, the value of L can be from 100 nm to 1000 nm.

[0082] As an example, the number x of microstructures 211 in the extracted loose layer 210 can be counted in the following way: if the microstructure 211 is a complete structure, the value of the number x is increased by one; if the volume of the microstructure 211 is greater than or equal to 1 / 2 of the volume of the complete structure, the value of the number x is increased by one; if the volume of the microstructure 211 is less than 1 / 2 of the volume of the complete structure, the value of the number x remains unchanged. In other words, the microstructure 211 is not included in the number x.

[0083] L 2 The number x of microstructures 211 in the loose layer 210 with a square area can reflect the density of the loose layer 210, while L 2 The number x of microstructures 211 in the cubic volume porous layer 210 and the size D of the microstructures 211 in the direction perpendicular to the thickness of the substrate 100 can jointly reflect the number and size of air gaps 212 between the microstructures 211. Based on this, the embodiments of this application can not only limit the size D of the microstructures 211 in the direction perpendicular to the thickness of the substrate 100 by utilizing the above conditional formula, thereby controlling the density and refractive index of the porous layer 210, but also change the refractive index of the porous layer 210 by taking advantage of the positive correlation between the number x of microstructures 211 and the size D of microstructures 211 and the refractive index of the porous layer 210. The fewer the number x of microstructures 211 and the more air gaps 212, the lower the refractive index of the porous layer 210; conversely, the more the number x of microstructures 211 and the fewer air gaps 212, the higher the refractive index of the porous layer 210.

[0084] In some implementations, the number x and average value of microstructures 211 And the side length L satisfies:

[0085]

[0086] In this embodiment of the application, the conditional expression is used to limit L as described above. 2The density of the porous layer 210 can be controlled by the number x of microstructures 211 and the size D of microstructures 211 in the porous layer 210 with a square area, so that it can balance reliability and low-reflectivity performance.

[0087] For example, the closer the value of the above conditional expression is to the left endpoint of 0.12, the more porous the porous layer 210 is, and the lower its refractive index. Conversely, the closer the value of the above conditional expression is to the right endpoint of 0.98, the more dense the porous layer 210 is, and the higher its refractive index is. If the value of the above conditional expression is less than 0.12, the porous layer 210 may be too porous, resulting in excessive brittleness and significantly reduced mechanical properties, thus failing to meet practical requirements. Similarly, if the value of the above conditional expression is greater than 0.98, the porous layer 210 may be too dense, resulting in a high refractive index, and thus failing to achieve the effect of low reflectivity.

[0088] As an example, the inherent refractive index n of the porous layer 210 s Satisfies: 1.3≤n s ≤1.65.

[0089] In some embodiments, the film structure 200 is an anti-reflective film. For example, the maximum reflectivity of the coating structure is no greater than 0.3% in the 400nm–720nm wavelength range. For instance, the maximum reflectivity of the coating structure is no greater than 0.1% in the 400nm–680nm wavelength range. In this embodiment, forming air gaps 212 in the porous layer 210 reduces the density of the porous layer 210, making it more porous, thereby reducing the refractive index of the porous layer 210 and further reducing the reflectivity of the entire film structure 200. Compared to a continuous dense film of the same material with no or almost no air gaps 212, the refractive index of the porous layer 210 can decrease by 5%–30%. For example, the refractive index of the porous layer 210 can be reduced to 1.1–1.45. The material of the porous layer 210 can include, but is not limited to, at least one of SiO2, Al2O3, TiO2, and MgF2.

[0090] Considering that the thickness of the porous layer 210 is typically in the nanometer range and its own strength is relatively low, a connecting layer 220 can be provided between the porous layer 210 and the substrate 100 to enable the porous layer 210 to undergo thermal deformation simultaneously with the substrate 100, thereby improving its stability and making it less prone to breakage. This also prevents the porous layer 210 from detaching under special environments such as moisture erosion, enhances its firmness and tensile strength on the substrate 100, and increases the bonding force between the porous layer 210 and the substrate 100. Furthermore, the connecting layer 220 can also adjust the effective optical path between the porous layer 210 and the substrate 100. It should be noted that a single connecting layer 220 or multiple connecting layers 220 can be provided between the porous layer 210 and the substrate 100. When multiple connecting layers 220 are provided between the porous layer 210 and the substrate 100, the multiple connecting layers 220 are stacked sequentially along the thickness direction of the substrate 100, with adjacent connecting layers 220 made of different materials. The connecting layer 220 can be an oxide layer. For example, the material of the connecting layer 220 can include, but is not limited to, at least one of Nb2O5, SiO2 and TiO2.

[0091] In some embodiments, the material of the substrate 100 may include, but is not limited to, plastic, glass, metal, or composite materials. Since the thermal deformation of plastic is greater than that of glass, and the adhesion of the porous layer 210 to plastic is less than that to glass, in order to improve the firmness of the porous layer 210 on the substrate 100 and prevent the porous layer 210 from cracking, a connecting layer 220 may be provided between the porous layer 210 and the substrate 100 when the substrate 100 is made of plastic. When the substrate 100 is made of glass, a connecting layer 220 may be provided between the porous layer 210 and the substrate 100, or it may not be provided. Taking the substrate 100 as an optical lens as an example, the presence of the porous layer 210 can not only reduce the reflection of the optical lens and increase the light transmittance, significantly reducing the risk of ghosting and stray light, but also improve the photoelectric conversion efficiency, resulting in a clearer image.

[0092] In addition, this application also provides a method for preparing a coating structure, the method comprising:

[0093] S100, providing substrate 100;

[0094] S200, a film structure 200 is formed on one side of the substrate 100. The film structure 200 includes a loose layer 210. The loose layer 210 includes a plurality of columnar microstructures 211. The plurality of microstructures 211 are distributed in a direction perpendicular to the thickness of the substrate 100. There are air gaps 212 between adjacent microstructures 211.

[0095] As an example, the film structure 200 can be formed by placing a substrate 100 in a reaction chamber, wherein the material of the substrate 100 may include, but is not limited to, plastic, glass, metal, or composite materials; processing the film material 400 in the reaction chamber using a vapor deposition process, and introducing a collision gas into the reaction chamber to deposit the film material 400 on one side of the substrate 100 to form a porous layer 210. In this embodiment of the application, introducing a collision gas into the reaction chamber during the vapor deposition process can reduce the kinetic energy of the film material particles by increasing the number of collisions, making them more inclined to grow vertically on the substrate 100 to form columnar microstructures 211. This results in the final porous layer 210 having air gaps 212. The presence of air gaps 212 makes the porous layer 210 more porous, so that when light is reflected at the interface between the microstructure 211 and the air gaps 212, destructive interference can occur between the reflected light rays. At the same time, the scattering of light within the air gaps 212 increases, thereby significantly reducing the refractive index of the porous layer 210. Furthermore, this method alters the porosity of the porous layer 210 by introducing a collision gas, thus allowing the material of the porous layer 210 to be unrestricted.

[0096] As an example, the collision gas includes at least one of inert gas, oxidizing gas, and inactive gas. For instance, the collision gas may include at least one of argon, oxygen, or nitrogen. The film material 400 may be an organic compound, an inorganic compound, or a mixture thereof. For example, the material of the film material 400 may include at least one of SiO2, Al2O3, TiO2, and MgF2.

[0097] In some embodiments, the minimum dimension C of the air gap 212 in the direction perpendicular to the thickness of the substrate 100 is negatively correlated with the deposition temperature of the vapor deposition process. The higher the deposition temperature of the vapor deposition process, the greater the kinetic energy of the film particles formed by the evaporation of the film material 400, and the greater the energy of horizontal diffusion of the clusters formed by the aggregation of film particles on the surface of the substrate 100. This results in a denser final porous layer 210; in other words, the smaller the air gap 212 between the microstructures 211 of the porous layer 210. Conversely, the lower the temperature of the vapor deposition process, the more porous the porous layer 210, and the larger the air gap 212 between the microstructures 211. As an example, the deposition temperature can be from 20°C to 400°C.

[0098] The minimum dimension C of the air gap 212 in the direction perpendicular to the thickness of the substrate 100 is negatively correlated with the vacuum level of the reaction chamber. A higher vacuum level in the reaction chamber indicates fewer collision gases introduced into the chamber, resulting in fewer collisions between film particles, less kinetic energy loss, and greater horizontal diffusion energy of the clusters formed by the agglomeration of film particles on the substrate 100 surface. This leads to a denser final porous layer 210; in other words, a smaller air gap 212 between the microstructures 211 of the porous layer 210. Conversely, a lower vacuum level in the reaction chamber results in a more porous layer 210 and a larger air gap 212 between the microstructures 211. For example, the vacuum level of the reaction chamber can range from 0.0001 Pa to 0.1 Pa.

[0099] The minimum dimension C of the air gap 212 in the direction perpendicular to the thickness of the substrate 100 is positively correlated with the amount of collision gas introduced. The more collision gas introduced into the reaction chamber, the more collisions occur between the film particles, the greater the kinetic energy loss of the film particles, and the less energy is diffused horizontally across the clusters formed by the aggregation of film particles on the surface of the substrate 100. This results in a more porous final layer 210; in other words, the larger the air gap 212 between the microstructures 211 of the porous layer 210. Conversely, the less collision gas introduced into the reaction chamber, the denser the porous layer 210, and the smaller the air gap 212 between the microstructures 211. As an example, the amount of collision gas introduced can range from 1 sccm to 1000 sccm.

[0100] In some implementations, the deposition temperature T, the vacuum level P of the reaction chamber, and the flow rate F of the collision gas in the vapor deposition process satisfy the following:

[0101]

[0102] For example, at T = 400℃, P = 0.0001Pa, and F = 1 sccm, F / (-T*lgP) = 0.000625. In this case, the loose layer 210 is more compact, the air gaps 212 between the microstructures 211 are smaller, and the ratio of the size D of the microstructure 211 to the minimum size C of the air gap 212 is larger. As another example, at T = 20℃, P = 0.1Pa, and F = 1000 sccm, F / (-T*lgP) = 50. In this case, the loose layer 210 is more porous, the air gaps 212 between the microstructures 211 are larger, and the ratio of the size D of the microstructure 211 to the minimum size C of the air gap 212 is smaller.

[0103] In some embodiments, the step of forming the film structure 200 before forming the porous layer 210 may further include forming a connecting layer 220 on one side of the substrate 100. For example, only one connecting layer 220 may be formed on one side of the substrate 100. Alternatively, multiple connecting layers 220 may be formed sequentially on one side of the substrate 100, with adjacent connecting layers 220 made of different materials. The connecting layer 220 may also be formed on one side of the substrate 100 by a vapor deposition process, and the connecting layer 220 may be an oxide layer; for example, the material of the connecting layer 220 may include, but is not limited to, at least one of Nb2O5, SiO2, and TiO2.

[0104] The following are examples illustrating different structural forms of the coating structure in the embodiments of this application:

[0105] Example 1

[0106] like Figure 1 As shown, in this embodiment, the coating structure includes a substrate 100 and a film structure 200 formed on one side of the substrate 100. The film structure 200 includes a loose layer 210, which includes a plurality of columnar microstructures 211. The plurality of microstructures 211 are distributed in a direction perpendicular to the thickness of the substrate 100, and there are air gaps 212 between adjacent microstructures 211.

[0107] In this embodiment, the above-mentioned coating structure can be prepared by the following method: A substrate 100 and a film 400 are placed in a reaction chamber. The material of the film 400 is SiO2, and the material of the substrate 100 is glass. The film 400 is vaporized using a physical vapor deposition (PVD) process via evaporation or sputtering. In the reaction chamber, an ion source generator 300 ionizes the collision gas (O2) into charged oxygen ions, causing the film 400 to deposit on one side of the substrate 100 to form a porous layer 210. The deposition temperature in the reaction chamber is 80°C, the O2 flow rate is 200 sccm, and the vacuum level in the reaction chamber is 0.04 Pa.

[0108] During the above process, the film material 400 vaporizes to form SiO2 molecules with a certain energy and is directed towards the substrate 100. Simultaneously, the ion source generator 300 ionizes the collision gas O2 into charged oxygen ions, which are then directed towards the substrate 100 within the reaction chamber. During the process of SiO2 molecules and oxygen ions approaching the substrate 100, frequent collisions occur, leading to a decrease in the kinetic energy of the SiO2 molecules. Some SiO2 molecules reaching the surface of the substrate 100 are reflected, while others are adsorbed onto the surface. The adsorbed SiO2 molecules are then transferred to suitable locations through surface diffusion. With continuous adsorption and diffusion, multiple SiO2 molecules agglomerate to form clusters. Because the kinetic energy of the SiO2 molecules is reduced due to collisions, the energy of the clusters is insufficient for large-area horizontal diffusion, causing the clusters to tend to grow vertically, forming columnar microstructures 211. Air gaps 212 exist between the microstructures 211, ultimately forming a SiO2 layer with a refractive index of 1.31, which is the porous layer 210. Among them, the dimension D of the microstructure 211 in the thickness direction perpendicular to the substrate 100 is 100nm to 200nm, and the dimension of the microstructure 211 in the thickness direction of the substrate 100 is 200nm. In other words, the thickness of the loose layer 210 is 200nm, and the minimum dimension C of the air gap 212 in the thickness direction perpendicular to the substrate 100 is 15nm to 30nm.

[0109] As can be seen, in this embodiment, during the formation of the porous layer 210, the ion source generator 300 in the reaction chamber ionizes the collision gas O2 into charged oxygen ions, thereby increasing the number of collisions and reducing the kinetic energy of the film particles. This makes them more inclined to grow vertically on the substrate 100, forming columnar microstructures 211. Consequently, the final porous layer 210 has air gaps 212. The presence of air gaps 212 makes the porous layer 210 more porous, allowing destructive interference to occur between reflected light rays at the interface between the microstructures 211 and the air gaps 212. Simultaneously, light scattering increases within the air gaps 212, significantly reducing the refractive index of the porous layer 210. Figure 11 As shown, the maximum reflectivity of the coated structure is no greater than 0.3% in the 400nm–720nm wavelength range.

[0110] Example 2

[0111] like Figure 2As shown, this embodiment is basically the same as embodiment 1. The parts that are the same as in embodiment 1 will not be repeated here. The difference lies in that: in this embodiment, the material of the substrate 100 is resin plastic, and four connecting layers 220 are provided between the substrate 100 and the porous layer 210. The materials of adjacent connecting layers 220 are different. The four connecting layers 220 are formed by alternating stacks of silicon oxide layers and titanium oxide layers. The connecting layer 220 in contact with the substrate 100 is a titanium oxide layer, and the connecting layer 220 in contact with the porous layer 210 is a silicon oxide layer.

[0112] For ease of description, the four connecting layers 220, from the substrate 100 to the porous layer 210, will be referred to sequentially as the first connecting layer 221, the second connecting layer 222, the third connecting layer 223, and the fourth connecting layer 224. Referring to Table 1, the above-mentioned coating structure in this embodiment can be prepared by the following method: a first connecting layer 221 is formed on one side of the substrate 100, the first connecting layer 221 being a titanium oxide layer with a thickness of 9.13 nm; a second connecting layer 222 is formed on the side of the first connecting layer 221 facing away from the substrate 100, the second connecting layer 222 being a silicon oxide layer with a thickness of 51.15 nm; a third connecting layer 223 is formed on the side of the second connecting layer 222 facing away from the first connecting layer 221, the third connecting layer 223 being a titanium oxide layer with a thickness of 13.68 nm; and a fourth connecting layer 224 is formed on the side of the third connecting layer 223 facing away from the second connecting layer 222, the fourth connecting layer 224 being a silicon oxide layer with a thickness of 114.01 nm. The first connecting layer 221 to the fourth connecting layer 224 can all be formed by vapor deposition. The MgF2 film material in the reaction chamber is vaporized by vapor deposition, and an impact gas, Ar, is introduced into the reaction chamber so that the film material 400 is deposited on the side of the fourth connecting layer 224 away from the third connecting layer 223 to form a loose layer 210. The loose layer 210 is a magnesium fluoride layer with a thickness of 118.69 nm.

[0113] Table 1. Materials, thicknesses, and refractive indices of the connecting layer 220 and the porous layer 210.

[0114] Material Thickness / nm Refractive index First connection layer <![CDATA[TiO2]]> 9.13 2.35 Second connection layer <![CDATA[SiO2]]> 51.15 1.45 Third connection layer <![CDATA[TiO2]]> 13.68 2.35 Fourth connection layer <![CDATA[SiO2]]> 114.01 1.45 loose layer <![CDATA[MgF2]]> 118.69 1.18

[0115] During the formation of the second connecting layer 222 and the fourth connecting layer 224, O2 is introduced into the reaction chamber at a rate of 60 sccm, the deposition temperature is 100°C, and the vacuum level is 0.0001 Pa. During the formation of the porous layer 210, the deposition temperature is 100°C, the collision gas (Ar) is introduced at a rate of 400 sccm, and the vacuum level is 0.05 Pa.

[0116] During the formation of the porous layer 210, the film material 400 vaporizes to form MgF2 molecules with a certain energy, which are then directed toward the substrate 100. The MgF2 molecules frequently collide with Ar molecules in the collision gas within the reaction chamber, causing a decrease in their kinetic energy. Some of the MgF2 molecules reaching the surface of the substrate 100 are reflected, while others are adsorbed onto the surface of the substrate 100. The adsorbed MgF2 molecules then diffuse to suitable locations via surface diffusion. With continuous adsorption and diffusion, multiple MgF2 molecules agglomerate to form clusters. Because the kinetic energy of the MgF2 molecules decreases due to collisions, the clusters lack sufficient energy for large-area horizontal diffusion, causing them to tend to grow vertically, forming columnar microstructures 211. Air gaps 212 exist between the microstructures 211, ultimately forming a MgF2 layer with a refractive index of 1.18, which is the porous layer 210. Among them, the dimension D of the microstructure 211 in the thickness direction perpendicular to the substrate 100 is 210nm to 252nm, and the dimension of the microstructure 211 in the thickness direction of the substrate 100 is 118.69nm. In other words, the thickness of the loose layer 210 is 118.69nm, and the minimum dimension C of the air gap 212 in the thickness direction perpendicular to the substrate 100 is 28nm to 38nm.

[0117] As can be seen, in this embodiment, introducing argon gas into the reaction chamber during the formation of the porous layer 210 increases the number of collisions, thereby reducing the kinetic energy of the film particles and making them more inclined to grow vertically on the substrate 100 to form columnar microstructures 211. This results in the final porous layer 210 having air gaps 212. The presence of these air gaps 212 makes the porous layer 210 more porous, allowing destructive interference between reflected light rays at the interface between the microstructures 211 and the air gaps 212. Simultaneously, light scattering within the air gaps 212 increases, significantly reducing the refractive index of the porous layer 210. The reduction in the refractive index of the porous layer 210 (i.e., the MgF2 layer) further reduces the reflectivity of the entire film structure 200. Furthermore, the reduced refractive index of the porous layer 210 is closer to the refractive index of air, thus reducing the number of layers in the overall film structure 200. Figure 12 As shown, the maximum reflectivity of the coating structure is no greater than 0.1% in the 400nm to 700nm wavelength range. Furthermore, in this embodiment, by forming a multilayer connecting layer 220 between the substrate 100 and the porous layer 210, the effective optical path between the substrate 100 and the porous layer 210 can be adjusted using the connecting layer 220.

[0118] Example 3

[0119] like Figure 3As shown, this embodiment is basically the same as embodiment 2. The parts that are the same as in embodiment 1 will not be repeated here. The difference lies in that: in this embodiment, the material of the substrate 100 is metal, and five connecting layers 220 are provided between the substrate 100 and the porous layer 210. The materials of adjacent connecting layers 220 are different. The five connecting layers 220 are formed by alternating stacks of niobium pentoxide layers and silicon oxide layers. The connecting layer 220 in contact with the substrate 100 is a niobium pentoxide layer, and the connecting layer 220 in contact with the porous layer 210 is also a niobium pentoxide layer.

[0120] For ease of description, the five connecting layers 220, from the substrate 100 to the loose layer 210, will now be referred to as the first connecting layer 221, the second connecting layer 222, the third connecting layer 223, the fourth connecting layer 224, and the fifth connecting layer 225, respectively. Referring to Table 2, the above-mentioned coating structure in this embodiment can be prepared by the following method: a first connecting layer 221 is formed on one side of the substrate 100, the first connecting layer 221 being a niobium pentoxide layer with a thickness of 14.6 nm; a second connecting layer 222 is formed on the side of the first connecting layer 221 away from the substrate 100, the second connecting layer 222 being a silicon oxide layer with a thickness of 40.79 nm; a third connecting layer 223 is formed on the side of the second connecting layer 222 away from the first connecting layer 221, the third connecting layer 223 being a niobium pentoxide layer with a thickness of 30.78 nm; a fourth connecting layer 224 is formed on the side of the third connecting layer 223 away from the second connecting layer 222, the fourth connecting layer 224 being a silicon oxide layer with a thickness of 48.31 nm; and a fifth connecting layer 225 is formed on the side of the fourth connecting layer 224 away from the third connecting layer 223, the fifth connecting layer 225 being a niobium pentoxide layer with a thickness of 18.64 nm. The first to fifth connecting layers 221 and 225 can all be formed by vapor deposition. The SiO2 film material in the reaction chamber is vaporized using vapor deposition, and an impact gas, N2, is introduced into the reaction chamber. This causes the film material 400 to deposit on the side of the fifth connecting layer 225 opposite to the fourth connecting layer 224, forming a porous layer 210. The porous layer 210 is a silicon oxide layer with a thickness of 117.65 nm. During the formation of the porous layer 210, the deposition temperature in the reaction chamber is 300°C, the N2 flow rate is 600 sccm, and the vacuum level in the reaction chamber is 0.08 Pa.

[0121] Table 2. Materials, thicknesses, and refractive indices of the connecting layer 220 and the porous layer 210.

[0122] Material Thickness / nm Refractive index First connection layer <![CDATA[Nb2O5]]> 14.6 2.3 Second connection layer <![CDATA[SiO2]]> 40.79 1.45 Third connection layer <![CDATA[Nb2O5]]> 30.78 2.3 Fourth connection layer <![CDATA[SiO2]]> 48.31 1.45 Fifth connection layer <![CDATA[Nb2O5]]> 18.64 2.3 loose layer <![CDATA[SiO2]]> 117.65 1.25

[0123] During the formation of the porous layer 210, the film material 400 vaporizes to form SiO2 molecules with a certain energy, which are then directed toward the substrate 100. The SiO2 molecules frequently collide with N2 molecules in the collision gas within the reaction chamber, causing a decrease in their kinetic energy. Some of the SiO2 molecules reaching the surface of the substrate 100 are reflected, while others are adsorbed onto the surface. The adsorbed SiO2 molecules then diffuse to suitable locations via surface diffusion. With continuous adsorption and diffusion, multiple SiO2 molecules agglomerate to form clusters. Because the kinetic energy of the SiO2 molecules decreases due to collisions, the clusters lack sufficient energy for large-area horizontal diffusion, causing them to tend to grow vertically, forming columnar microstructures 211. Air gaps 212 exist between the microstructures 211, ultimately forming a SiO2 layer with a refractive index of 1.25, which is the porous layer 210. Among them, the dimension D of the microstructure 211 in the thickness direction perpendicular to the substrate 100 is 210nm to 252nm, and the dimension of the microstructure 211 in the thickness direction of the substrate 100 is 117.65nm. In other words, the thickness of the loose layer 210 is 117.65nm, and the minimum dimension C of the air gap 212 in the thickness direction perpendicular to the substrate 100 is 28nm to 38nm.

[0124] As can be seen, in this embodiment, by introducing nitrogen gas into the reaction chamber during the formation of the porous layer 210, the kinetic energy of the film particles can be reduced by increasing the number of collisions, making them more inclined to grow vertically on the substrate 100 and form columnar microstructures 211. This results in the final porous layer 210 having air gaps 212. The presence of air gaps 212 makes the porous layer 210 more porous, allowing destructive interference to occur between reflected light rays at the interface between the microstructures 211 and the air gaps 212. Simultaneously, light scattering increases within the air gaps 212, thereby significantly reducing the refractive index of the porous layer 210. Figure 13 As shown, the maximum reflectivity of the coating structure is no greater than 0.3% in the 400nm to 700nm wavelength range. Furthermore, in this embodiment, by forming a multilayer connecting layer 220 between the substrate 100 and the porous layer 210, the effective optical path between the substrate 100 and the porous layer 210 can be adjusted using the connecting layer 220.

[0125] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. As an example, the steps described in this invention disclosure can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this application can be achieved, and this is not limited herein.

[0126] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A coating structure, characterized in that, include: Substrate; as well as A film structure located on one side of the substrate and including a porous layer; The porous layer includes multiple columnar microstructures distributed in a direction perpendicular to the thickness of the substrate, with air gaps between adjacent microstructures.

2. The coating structure according to claim 1, wherein, The microstructure has a size of 10 nm to 500 nm in the direction perpendicular to the thickness of the substrate.

3. The coating structure according to claim 1, wherein, The minimum size of the air gap in the direction perpendicular to the thickness of the substrate is 3nm to 50nm.

4. The coating structure according to claim 1, wherein, The inherent refractive index n of the porous layer s L 2 The number x of the microstructures in the porous layer of square area, and the average size of x of the microstructures in the direction perpendicular to the thickness of the substrate. And the refractive index n0 of air satisfies: Where L is L 2 The side length of the projection of the loose layer of square area onto a plane perpendicular to the thickness direction of the substrate, where x is an integer.

5. The coating structure according to claim 4, wherein, The number x of the microstructures, the average value The side length L satisfies:

6. The coating structure according to claim 4, wherein, The inherent refractive index n of the porous layer s satisfy: 1.3≤n s ≤1.65。 7. The coating structure according to claim 1, wherein, The membrane structure is an anti-reflective membrane.

8. The coating structure according to claim 7, wherein, Within the 400nm–720nm wavelength range, the maximum reflectivity of the coating structure is no greater than 0.3%.

9. The coating structure according to claim 1, wherein, The material of the porous layer includes at least one of SiO2, Al2O3, TiO2 and MgF2.

10. The coating structure according to any one of claims 1 to 9, wherein, The membrane structure further includes: A connecting layer is located between the substrate and the porous layer.

Images