Concave-convex structure film, preparation process thereof and shading ring

Abstract

The invention discloses a concave-convex structure film, a preparation technology thereof and a shading ring, and belongs to the technical field of optical device surface treatment.The concave-convex structure film is arranged on the surface of a shading ring base body and comprises a micron-sized concave-convex transition layer and a hard extinction layer from bottom to top, and the preparation technology of the concave-convex structure film adopts a two-step method. The method comprises the following steps: growing a concave-convex transition layer with a micron-sized concave-convex structure on the surface of a matrix in situ by combining a sol-gel spin-coating method with stepped heat treatment; secondly, a high-hardness and low-reflectivity hard matting layer of nitrogen and carbide is deposited on the surface of the concave-convex transition layer through the multi-arc ion plating technology, the hard matting layer perfectly reforms the concave-convex morphology of the concave-convex transition layer, and a micro-nano composite stable light trap structure is formed; the surface structure of the shading ring prepared by the invention has excellent wide-spectrum extinction performance, extremely high film-substrate binding force, good wear resistance and environmental stability, and is particularly suitable for a precise optical system with extremely high stray light suppression requirements.

Description

Technical Field

[0001] This invention relates to the field of optical device manufacturing and surface treatment technology, and more specifically, to a textured film, its preparation process, and a light-shielding ring. Background Technology

[0002] In optical imaging systems, the aperture diaphragm is a key component for controlling the beam aperture and suppressing stray light. Stray light can cause glare and ghosting on the image plane, severely reducing image contrast and resolution. To maximize the absorption of non-imaging beams, the surface of the aperture diaphragm needs to undergo efficient extinction treatment. Currently, common aperture diaphragm surface extinction treatment technologies mainly include:

[0003] Chemical / electrochemical blackening treatment: such as blackening and bluing treatment. This method is low in cost, but the resulting oxide film is thin, the matting effect is limited, the wear resistance and corrosion resistance are poor, and the treatment effect is not good for some metal materials.

[0004] Spraying matte paint or pasting matte velvet: Spraying black matte paint or pasting black velvet on the surface has a good matte effect, but the adhesion, abrasion resistance and high temperature and humidity resistance of the paint or velvet are poor. It is easy to fall off and age under long-term use or harsh environment, and may produce volatile substances to contaminate the lens.

[0005] Traditional physical vapor deposition black films: such as black oxide films and nitride films prepared by magnetron sputtering or evaporation deposition. These methods produce uniform and dense films with better adhesion than spraying. However, the film surface is usually relatively flat, and the absorption of light mainly depends on the intrinsic light absorption of the material. They lack effective microstructure light trapping effects, and the extinction performance under ultra-large angle incident light is still not ideal. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a concave-convex structure film with a micro-nano composite light-trapping structure and its preparation process, as well as a light-shielding ring using this structure film. This structure film is prepared by a unique two-step method and achieves comprehensive performance of high adhesion, high hardness, and wide-spectrum efficient light extinction.

[0007] To achieve the above objectives, the present invention provides the following technical solution: In one aspect, the present invention provides a textured film, wherein the textured film is disposed on the surface of a light-shielding ring substrate, and the textured film comprises, from bottom to top, a textured transition layer and a hard matting layer; the textured transition layer is a polycrystalline oxide layer formed in situ on the surface of the light-shielding ring substrate by a sol-gel method, and has a micron-level textured morphology with an average roughness of [missing information]. The hard matte layer is a metal nitride, metal carbonitride, or metal oxide layer deposited on the surface of the uneven transition layer by physical vapor deposition. The hard matte layer replicates the surface morphology of the uneven transition layer, and its intrinsic color is dark or black, with a nanohardness of not less than [value missing]. Furthermore, in the technical solution of the present invention, the material of the uneven transition layer includes silicon oxide or titanium oxide doped with transition metal elements, wherein the transition metal elements include at least one of iron, copper, and chromium; the material of the hard matte layer is... , , , , , At least one of them, the thickness of the hard matte layer is .

[0008] Another aspect of the present invention provides a process for preparing an uneven structured film, used to achieve an uneven structured film as described above, specifically including the following steps: S1, substrate pretreatment: cleaning and surface activation treatment of the light-shielding ring substrate, including ultrasonic cleaning and plasma activation of the light-shielding ring substrate; S2, preparation of transition layer sol: dissolving a metal alkoxide precursor, a transition metal salt, a structure directing agent, and a catalyst in a solvent, and forming a uniform sol by static aging, wherein the metal alkoxide precursor is at least one of a silanol precursor or a titanium alkoxide precursor, the transition metal salt is at least one of ferric nitrate, copper nitrate, or chromium chloride, the structure directing agent is at least one of polyvinylpyrrolidone, polyethylene glycol, or a block copolymer, and the catalyst is an acid catalyst or a base catalyst; S3, spin coating and low-temperature heat treatment: uniformly spin coating the sol obtained in step S2 onto the surface of the pretreated light-shielding ring substrate, the spin coating speed being [missing information]. A wet film is formed, and then the wet film is subjected to low-temperature heat treatment to gel it and form a gel film. The treatment temperature for low-temperature heat treatment is... Processing time is S4. High-temperature crystallization: Under a protective atmosphere or in air, the gel film formed in step S3 is subjected to a step-by-step heating heat treatment at a heating rate of [missing information]. Finally in The bottom is insulated, and the insulation time is... This process crystallizes the gel film and decomposes to remove organic components, forming a transition layer with a micron-scale uneven structure; S5, Ion plating deposition: The light-shielding ring substrate treated in step S4 is placed in a multi-arc ion plating equipment to deposit a hard matting layer on the surface of the uneven transition layer, specifically including: S51, The light-shielding ring substrate is placed in the vacuum chamber of the multi-arc ion plating equipment, and a vacuum is drawn until the background pressure is lower than S52. Introduce argon gas into the vacuum chamber of the equipment and turn on the workpiece bias voltage for ion bombardment cleaning; S53. Turn on the metal target arc source, introduce the reactive gas, adjust the workpiece bias voltage, arc current, and working gas pressure to perform reactive ion plating, and control the deposition temperature at [temperature range missing]. the following.

[0009] In another aspect, the present invention provides a light-shielding ring, including a light-shielding ring substrate and a textured film as described above, wherein the textured film covers the surface of the light-shielding ring substrate that needs to suppress stray light, and the material of the light-shielding ring substrate is a heat-resistant metal or alloy.

[0010] Beneficial Effects: In summary, this invention provides a textured film, its fabrication process, and a light-shielding ring. Compared with existing technologies, this invention achieves multiple scattering of light through a micron-level rough structure, while combining it with a hard extinction layer possessing intrinsically high absorptivity. The resulting "micro-nano composite" structure exhibits extremely low reflectivity across a wide spectral range, significantly superior to a single flat black film. Specifically, this invention uses a sol-gel spin-coating method combined with stepped heat treatment to grow a textured transition layer with a micron-level textured structure in situ on the substrate surface. A high-hardness, low-reflectivity hard extinction layer of nitrogen and carbides is deposited on the surface of this transition layer using multi-arc ion plating technology. This hard extinction layer perfectly replicates the textured morphology of the transition layer, forming a stable light trap structure of the micro-nano composite. The surface structure of the light-shielding ring prepared by this invention possesses excellent wide-spectral extinction performance, extremely high film-substrate adhesion, good wear resistance, and environmental stability, making it particularly suitable for precision optical systems with extremely high requirements for stray light suppression.

[0011] Other features and advantages of the present invention will be set forth in the following description. Attached Figure Description

[0012] To more clearly illustrate the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a flowchart of a fabrication process for an unevenly structured membrane according to an embodiment of the present invention. Detailed Implementation

[0014] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0015] To address the problems mentioned in the background art, this embodiment provides a concave-convex structure film with a micro-nano composite light-trapping structure and its preparation process, as well as a light-shielding ring using the concave-convex structure film. The concave-convex structure film is prepared through a unique two-step method, achieving comprehensive performance of high adhesion, high hardness, and wide-spectrum efficient light extinction.

[0016] This embodiment provides a textured film, which is disposed on the surface of a light-shielding ring substrate and includes a textured transition layer and a hard matting layer from bottom to top.

[0017] Specifically, in this embodiment, the uneven transition layer is a polycrystalline oxide layer grown in situ on the surface of the light-shielding ring substrate using the sol-gel method. The surface has a micron-level uneven morphology, with an average roughness of [missing information]. The uneven transition layer is made of silicon oxide or titanium oxide doped with transition metal elements, including at least one of iron, copper, and chromium. During preparation, the uneven transition layer is controlled by the precursor formulation and heat treatment process to naturally form a randomly distributed micron-level uneven morphology on its surface, i.e., an average roughness of [missing information]. This layer not only provides an ideal roughened substrate for subsequent film layers, but also has a certain light absorption capacity due to the doping of dark oxides, and it is chemically bonded to the metal substrate, resulting in strong adhesion.

[0018] Specifically, in this embodiment, the hard matte layer is a metal nitride, metal carbonitride, or metal oxide layer deposited on the surface of the uneven transition layer by physical vapor deposition. The hard matte layer replicates the surface morphology of the uneven transition layer, and its intrinsic color is dark or black, with a nanohardness of not less than [missing information]. The material of the hard matte layer is , , , , , At least one of them, with a thickness of During deposition, the hard matte layer is formed by ions spreading out in a high-energy state and perfectly replicating the micron-scale uneven structure of the transition layer. At the same time, it also has a certain roughness at the nanoscale. This composite structure of "micron-scale uneven substrate + replica" constitutes an efficient light trap. In addition, the hard matte layer provides extremely high wear resistance and chemical stability.

[0019] This embodiment also provides a process for preparing an uneven structured film, used to achieve an uneven structured film as described above. Figure 1 This is a flowchart of a fabrication process for a textured membrane according to an embodiment of the present invention, as shown below. Figure 1 As shown, the specific steps include: S1, substrate pretreatment: cleaning and surface activation of the light-shielding ring substrate, including ultrasonic cleaning and plasma activation; S2, preparation of transition layer sol: dissolving the metal alkoxide precursor, transition metal salt, structure directing agent, and catalyst in a solvent, and forming a uniform sol by static aging, wherein the metal alkoxide precursor is at least one of silanol or titanium alkoxide precursor, the transition metal salt is at least one of ferric nitrate, copper nitrate, or chromium chloride, the structure directing agent is at least one of polyvinylpyrrolidone, polyethylene glycol, or block copolymer, and the catalyst is an acid catalyst or a base catalyst; S3, spin coating and low-temperature heat treatment: uniformly spin coating the sol obtained in step S2 onto the surface of the pretreated light-shielding ring substrate at a spin coating speed of [missing information]. A wet film is formed, and then the wet film is subjected to low-temperature heat treatment to gel it and form a gel film. The treatment temperature is [temperature value missing]. Processing time is S4. High-temperature crystallization: Under a protective atmosphere or in air, the gel film formed in step S3 is subjected to a step-by-step heating heat treatment at a heating rate of [missing information]. Finally in The bottom is insulated, and the insulation time is... This process crystallizes the gel film and decomposes to remove organic components, forming a transition layer with a micron-scale uneven structure; S5, Ion plating deposition: The light-shielding ring substrate treated in step S4 is placed in a multi-arc ion plating equipment to deposit a hard matting layer on the surface of the uneven transition layer, specifically including: S51, The light-shielding ring substrate is placed in the vacuum chamber of the multi-arc ion plating equipment, and a vacuum is drawn until the background pressure is lower than S52. Introduce argon gas into the vacuum chamber of the equipment and turn on the workpiece bias voltage for ion bombardment cleaning; S53. Turn on the metal target arc source, introduce the reactive gas, adjust the workpiece bias voltage, arc current, and working gas pressure to perform reactive ion plating, and control the deposition temperature at [temperature range missing]. the following.

[0020] The following detailed description of each step is provided with reference to specific embodiments: A textured film for stainless steel light shielding rings and its preparation method: S1, Substrate pretreatment: The stainless steel light shielding ring substrate is ultrasonically cleaned successively in acetone and anhydrous ethanol. It was dried with nitrogen gas and then placed in an oxygen plasma cleaner. Power down-processing To improve surface hydrophilicity; S2, Preparation of transition layer sol: using tetraethyl orthosilicate (TEOS) as a silanolate precursor, ferric nitrate as a transition metal salt, polyvinylpyrrolidone (PVP) as a structure directing agent, acidic nitric acid as the catalyst, and ethanol and water as the solvent, according to the molar ratio. Mix and stir magnetically at room temperature. It forms a uniform, slightly reddish-brown sol, which is then left to stand and age. Among them, tetraethyl orthosilicate (TEOS) is the main source of silica network. Its reaction is mild and controllable. After hydrolysis and polycondensation, it tends to form a continuous, porous, but essentially amorphous or microcrystalline network structure.

[0021] S3. Spin Coating and Low-Temperature Heat Treatment: Fix the pretreated stainless steel light-shielding ring substrate onto the spin coater, add an appropriate amount of the sol obtained in step S2, and first... Rotation Spread the sol, then... Rotation Obtain a uniform wet film, and then immediately place the stainless steel light-shielding ring substrate covered with the wet film into... Preheating on hot plate The sol is gelled to form a gel film. A uniform wet film with a uniform thickness is obtained by centrifugal force of a spin coater. The uniform film thickness is the basis for obtaining a uniform uneven morphology. The preheating treatment allows the solvent (ethanol and water) to be slowly removed. The hydrolysis and polycondensation reaction of tetraethyl orthosilicate (TEOS) continues under acid catalysis to form a three-dimensional network. The wet film is transformed into a solid gel film. The preheating treatment can avoid the huge capillary force generated by the rapid evaporation of solvent, which would cause the film to crack.

[0022] S4. High-temperature crystallization: The stainless steel light-shielding ring substrate coated with a gel film is placed in a programmable muffle furnace and crystallized in air at high temperature. Heat up to Insulation To thoroughly remove organic matter, and then with Heat up to Insulation After furnace cooling, a dark-colored transition layer with a micron-sized particle-like aggregated texture is obtained. In the formation of this transition layer, vinylpyrrolidone (PVP) is the core component controlling the texture. PVP is a long-chain polymer that becomes entangled with a silica network formed by tetraethyl orthosilicate (TEOS). During the intermediate temperature stage of heat treatment (i.e., when the temperature reaches...),... During heat treatment, vinylpyrrolidone (PVP) decomposes, carbonizes, and is eventually burned off. Its removal leaves cavities in situ. The concentration and molecular weight of VVP directly determine the number, size, and distribution of these cavities. In this embodiment, a 0.03 molar ratio of VVP is sufficient to create abundant pores with submicron to micron scales. Iron ions in ferric nitrate partially incorporate into the silica network or form their own iron oxide nanoclusters. The presence of these heterogeneous phases formed by iron ions interferes with the uniform shrinkage and crystallization of the silica network, becoming non-uniform "shrinkage points." This causes localized stress and non-uniform densification of the film during heat treatment, thereby promoting the formation of an uneven structure. Simultaneously, its decomposition products (iron oxide) impart the intrinsic dark color of the film. During the heating process, vinylpyrrolidone (PVP) and residual organic solvents have sufficient time to decompose, oxidize, and escape gradually. During the heating phase, vinylpyrrolidone (PVP) is removed, leaving behind molecular chain-shaped voids and channels throughout the gel network, forming a porous, fragile, but well-defined inorganic framework, which further... During the heating process, the silica network begins to undergo structural relaxation and microcrystallization. Simultaneously, ferric nitrate decomposes into iron oxide nanocrystals. Driven by surface energy, these microcrystals and nanoclusters undergo Oswald ripening, i.e., small grains dissolve and large grains grow, further contributing to the surface roughening of the uneven transition layer. The gel network further densifies and shrinks at high temperatures. Due to the porosity left by vinylpyrrolidone (PVP) and the stress unevenness caused by iron doping, this shrinkage is anisotropic—some areas shrink more while others shrink less. This uneven shrinkage promotes the formation of an uneven structure on the surface of the uneven transition layer. S5, Ion plating deposition: The stainless steel light-shielding ring substrate coated with the uneven transition layer is placed into a multi-arc ion plating equipment and evacuated to... Argon gas was introduced until Ion bombardment cleaning of stainless steel light-shielding ring substrate by applying pulsed bias voltage. Then, the high-purity titanium target electric arc was activated, and nitrogen and acetylene were introduced, with a nitrogen to acetylene flow rate ratio of approximately The deposition temperature is controlled at approximately The deposition time is A dark gray-black layer was obtained on the surface of the uneven transition layer. Thin film, also known as a hard matte layer.

[0023] This embodiment also provides a light-shielding ring, including a light-shielding ring substrate and a textured film as described above. The textured film covers the surface of the light-shielding ring substrate that needs to suppress stray light. The material of the light-shielding ring substrate is a heat-resistant metal or alloy.

[0024] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A membrane with an uneven structure, characterized in that, Located on the surface of the light-shielding ring base, from bottom to top, including: The uneven transition layer is a polycrystalline oxide layer grown in situ on the surface of the light-shielding ring substrate using the sol-gel method. Its surface has a micron-level uneven morphology with an average roughness of [value missing]. A hard matte layer is a metal nitride, metal carbonitride, or metal oxide layer deposited on the surface of the uneven transition layer using physical vapor deposition. This hard matte layer replicates the surface morphology of the uneven transition layer, and its intrinsic color is dark or black, with a nanohardness of not less than [value missing]. The uneven transition layer is made of silicon oxide or titanium oxide doped with transition metal elements, wherein the transition metal elements include at least one of iron, copper, and chromium; the hard matte layer is made of... , , , , , At least one of them, with a thickness of .

2. A process for preparing an uneven-structured membrane, used to achieve the uneven-structured membrane as described in claim 1, characterized in that, Specifically, the following steps are included: S1. Substrate pretreatment: The light-shielding ring substrate is cleaned and surface activated; S2. Preparation of transition layer sol: The metal alkoxide precursor, transition metal salt, structure directing agent and catalyst are dissolved in a solvent and a uniform sol is formed by static aging; S3. Spin coating and low-temperature heat treatment: The sol obtained in step S2 is uniformly spin-coated onto the surface of the pretreated light-shielding ring substrate to form a wet film. The wet film is then subjected to low-temperature heat treatment to gel it and form a gel film. S4. High-temperature crystallization: Under a protective atmosphere or air, the gel film formed in step S3 is subjected to a stepwise temperature increase heat treatment, ultimately crystallizing... The heat treatment process allows the gel film to crystallize and decompose to remove organic components, forming a transitional layer with a micron-scale uneven structure. S5. Ion plating deposition: The light-shielding ring substrate after step S4 is placed in a multi-arc ion plating equipment to deposit a hard matting layer on the surface of the uneven transition layer.

3. The preparation process of an uneven structured membrane according to claim 2, characterized in that, In step S1, the cleaning and surface activation treatment of the light-shielding ring substrate specifically includes ultrasonic cleaning and plasma activation of the light-shielding ring substrate.

4. The preparation process of an uneven structured membrane according to claim 2, characterized in that, In step S2, the metal alkoxide precursor is at least one of a silanol precursor or a titanium alkoxide precursor; the transition metal salt is at least one of ferric nitrate, copper nitrate, or chromium chloride; the structure directing agent is at least one of polyvinylpyrrolidone, polyethylene glycol, or a block copolymer; and the catalyst is an acid catalyst or a base catalyst.

5. The preparation process of an uneven structured membrane according to claim 2, characterized in that, In step S3, the spin coating speed for uniformly spin-coating the sol obtained in step S2 onto the pretreated light-shielding ring substrate surface is [missing value]. The processing temperature for low-temperature heat treatment of the formed wet film is: Processing time is .

6. The preparation process of an uneven structured membrane according to claim 2, characterized in that, In step S4, the heating rate for the step-heating heat treatment of the gel film formed in step S3 is: Finally in The insulation time for the lower insulation is .

7. The preparation process of an uneven structured membrane according to claim 2, characterized in that, Step S5 specifically includes: S51, placing the light-shielding ring substrate into the vacuum chamber of the multi-arc ion plating equipment, and evacuating the vacuum until the background pressure is lower than the required pressure. S52. Introduce argon gas into the vacuum chamber of the equipment and turn on the workpiece bias voltage for ion bombardment cleaning; S53. Turn on the metal target arc source, introduce the reactive gas, adjust the workpiece bias voltage, arc current, and working gas pressure to perform reactive ion plating, and control the deposition temperature at [temperature range missing]. the following.

8. A light-shielding ring, characterized in that, It includes a light-shielding ring substrate and a textured film as described in claim 1, wherein the textured film covers the surface of the light-shielding ring substrate that needs to suppress stray light.

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