Coating process for manufacturing optical lens
By performing ion cleaning and surface activation on the optical lens substrate, alternating film deposition, and adjusting process parameters using an ion-assisted deposition source to optimize the internal stress difference, the problem of stress mismatch between film layers was solved, achieving a high-quality coating effect.
Patent Information
- Application Number
- CN202511678622.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-17
- Publication Date
- 2026-02-17
AI Technical Summary
In existing coating processes, the internal stress mismatch between high-refractive-index and low-refractive-index films leads to film cracks, deformation, or deterioration of optical properties. Furthermore, the lack of precise internal stress monitoring and compensation mechanisms results in unstable coating quality.
By performing ion cleaning and surface activation on the substrate, alternating deposition of high-refractive-index and low-refractive-index films, and adjusting process parameters using an ion-assisted deposition source, internal stress testing and adjustment are performed to optimize the internal stress difference between the films, resulting in a film with better density and adhesion.
It significantly reduced film cracking and peeling, improved the stability and optical performance of the coating, and increased the yield rate to 94%.
Smart Images
Figure CN121538599A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the general field of coating using vacuum evaporation, sputtering, ion implantation or chemical vapor deposition, and particularly to a coating process for manufacturing optical lenses. Background Technology
[0002] Optical lenses are widely used in modern industry, such as eyeglasses, camera lenses, and optical instruments, and their performance largely depends on the quality of the surface coating.
[0003] However, existing coating processes have the following problems:
[0004] During the vapor deposition process, insufficient control of the internal stress of the film layer can lead to stress mismatch between high-refractive-index and low-refractive-index films due to differences in material properties, resulting in film cracks, deformation, or deterioration of optical properties. Furthermore, in traditional processes, the density and adhesion of the film layer typically rely on empirical adjustments of process parameters, lacking precise internal stress monitoring and compensation mechanisms, thus causing unstable coating quality. Summary of the Invention
[0005] The purpose of this invention is to provide a coating process for manufacturing optical lenses to solve the problems existing in the prior art.
[0006] The technical solution of the present invention is: a coating process for manufacturing optical lenses, wherein the optical lenses include a substrate, and the coating process includes:
[0007] The preparation of the substrate and the vacuum chamber includes: before the substrate is placed into the vacuum chamber, the substrate is pretreated with an ion cleaning source, including cleaning and destatic treatment; the temperature and vacuum level of the vacuum chamber are adjusted to reach a first preset range and a second preset range, respectively.
[0008] The substrate is placed in a vacuum chamber and then subjected to deep cleaning and surface activation using an ion activation source.
[0009] In a vacuum chamber, high-refractive-index films and low-refractive-index films are deposited sequentially on the surface of a substrate by vapor deposition. Multiple high-refractive-index and low-refractive-index films are deposited alternately to form a color layer. At the same time, an ion-assisted deposition source is used to improve the density and adhesion of the high-refractive-index and low-refractive-index films.
[0010] The substrate coated with the color layer is immersed in the test reagent, and after a preset time interval, it is taken out to test the integrity of the coating.
[0011] Including internal stress testing: internal stress tests are performed on high-refractive-index films and low-refractive-index films respectively to obtain the first internal stress of the corresponding high-refractive-index film and the second internal stress of the corresponding low-refractive-index film.
[0012] Based on the difference between the first internal stress and the second internal stress, the ion-assisted deposition source is selectively activated during one of the deposition processes of the high-refractive-index film and the low-refractive-index film, or the power of the ion-assisted deposition source is changed during the other deposition process, so that the difference between the first internal stress and the second internal stress is reduced after deposition is completed.
[0013] Preferably, a bonding layer is vapor-deposited between the substrate and the color layer, the bonding layer being used to increase the adhesion between the color layer and the substrate; the material forming the bonding layer is any one of silicon monoxide, aluminum oxide, and chromium.
[0014] Preferably, the material forming the high refractive index film can be any one of titanium pentoxide, zirconium dioxide, and tantalum pentoxide;
[0015] The material that forms the low refractive index film can be either silicon dioxide or aluminum oxide.
[0016] Preferably, the high refractive index film layer is configured as three in the color layer, including a first high refractive index film layer, a second high refractive index film layer and a third high refractive index film layer that are gradually moved away from the substrate;
[0017] The low refractive index film layer is configured as three layers in the color layer, including a first low refractive index film layer, a second low refractive index film layer, and a third low refractive index film layer that are gradually moved away from the substrate.
[0018] Preferably, the thickness of the first high refractive index film is 80-100 nm, the thickness of the second high refractive index film is 70-90 nm, and the thickness of the third high refractive index film is 70-90 nm.
[0019] The thickness of the first low-refractive-index film is 80-100 nm, the thickness of the second low-refractive-index film is 70-90 nm, and the thickness of the third low-refractive-index film is 70-90 nm.
[0020] Preferably, the anolyte voltage of the ion-assisted deposition source is set to 130–140V, the anolyte current is set to 2–3A, the oxygen flow rate is set to 10–25 sccm, and the argon flow rate is set to 0–10 sccm.
[0021] Preferably, the first preset range is set to 45–65°C, and the second preset range is set to 3.0 × 10⁻⁶ °C. -5 ~5.0×10 -5 mbar.
[0022] Preferably, the anode voltage of the ion activation source is set to 80-100V, the anode current is set to 2-3A, and the argon flow rate is set to 0-20sccm.
[0023] Preferably, the detection reagent is a saline-chlorine solution prepared with a saline concentration of 3.5% and a chlorine concentration of 50 ppm; the preset time is set to 24-72 hours.
[0024] Compared with the prior art, the advantages of the present invention are:
[0025] This invention solves the core technical challenge of film cracking and detachment from the substrate caused by large internal stress differences between different film materials by conducting internal stress tests on high-refractive-index and low-refractive-index films separately, and selectively adjusting the target material and process parameters of the ion-assisted deposition source multiple times based on the test results. By using different ion-assisted deposition source parameters for high-refractive-index and low-refractive-index films, this invention employs different ion-assisted deposition source parameters. Furthermore, experimental data confirms that the stress difference between the optimized films is significantly reduced, and the film cracking phenomenon is completely eliminated after testing. Attached Figure Description
[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments:
[0027] Figure 1 This is a cross-sectional view of the optical lens structure described in this invention;
[0028] Figure 2 This is a schematic diagram of the coating peeling off on the optical lens in this invention;
[0029] Figure 3 This is a schematic diagram of the coating cracking on the optical lens in this invention;
[0030] Figure 4 This is a rendering of a product from the present invention. Detailed Implementation
[0031] In this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "multiple" means two or more, unless otherwise expressly defined.
[0032] In this application, unless otherwise expressly specified and limited, "above" or "below" a second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. The terms "installed," "connected," "joined," and "fixed," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0033] This application provides a coating process for manufacturing optical lenses, which improves the optical performance of optical lenses, reduces light reflection, increases light transmittance, and protects the lenses from scratches and contamination.
[0034] Among them, such as Figure 1 As shown, the optical lens includes a substrate as the main body, which is made of resin material, particularly polycarbonate. A color layer is attached to the surface of the substrate through a bonding layer, wherein the bonding layer is any one of silicon monoxide, aluminum oxide, and chromium, used to increase the adhesion between the color layer and the substrate. In this embodiment, to avoid the influence of the bonding layer on the color of the coated lens, silicon monoxide is used as the material of the bonding layer. The color layer is formed by alternating deposition of multiple film structures with high and low refractive indices, so that visible light is decomposed into different colors when it passes through the color layer.
[0035] The coating process described in this application is mainly used for vapor deposition of bonding layers, especially color layers, on the surface of a substrate. Vapor deposition involves placing the substrate at the top of a vacuum chamber and heating a specific compound placed at the bottom of the vacuum chamber using an electron gun, causing it to evaporate or sublimate into gaseous particles. These gaseous particles rise in a straight line in the vacuum environment of the vacuum chamber and eventually condense uniformly and deposit on the cooler substrate surface, thereby forming a thin and dense coating.
[0036] The present invention will be further described in detail below with reference to specific embodiments.
[0037] Example 1
[0038] A coating process for manufacturing optical lenses specifically includes the following steps:
[0039] Step 1: Prepare the substrate and vacuum chamber. Preparation includes: Before placing the substrate into the vacuum chamber, pre-treat the substrate using an ion cleaning source, including cleaning and destatication, to remove macroscopic particles such as dust, fibers, and debris adhering to the substrate surface. In this embodiment, an ion cleaning source is an ion gun. Specifically, the ion gun is used to blow clean the substrate surface for 180 seconds at a distance of 50mm from the substrate surface.
[0040] Furthermore, the temperature and vacuum level within the vacuum chamber are adjusted to reach the first preset range and the second preset range, respectively. In this embodiment, since the heat resistance deformation temperature of the substrate is 120-130℃, and considering the heat radiation generated during the operation of the electron gun and the ion-assisted deposition source within the vacuum chamber during the vapor deposition process, the first preset range is set to 45-65℃; considering the issue of molecular free path in a vacuum and the economic efficiency of vacuuming, the second preset range is set to 3.0 × 10⁻⁶. -5 ~5.0×10 -5 mbar; this allows the entire vapor deposition process to form a film at a suitable temperature and a high vacuum.
[0041] Step 2: Place the substrate in a vacuum chamber and use an ion activation source to perform deep cleaning and surface activation on the substrate.
[0042] Specifically, argon gas is introduced into the vacuum chamber, with the flow rate set to 0–20 sccm. The anode voltage of the ion activation source is adjusted to 80–100V, and the anode current to 2–3A. The ion activation source ionizes the argon gas to form argon ions. These positively charged argon ions are accelerated under the influence of an electric field to gain high kinetic energy, which is then used to bombard the surface of the substrate. This process removes monomolecular contaminants such as water molecules, grease, and gas molecules adhering to the substrate surface, achieving deep cleaning.
[0043] Argon ion bombardment increases the surface roughness of the substrate at the nanoscale, thereby increasing the actual contact area between the coating and the substrate. Furthermore, ion bombardment breaks down the polymer chains on the substrate surface, generating numerous dangling bonds and free radicals, forming high-energy active sites. These active sites form covalent bonds with subsequently deposited coating atoms, further enhancing the adhesion between the coating and the substrate.
[0044] Step 3: In a vacuum chamber, a high-refractive-index film and a low-refractive-index film are deposited sequentially on the surface of the substrate by vapor deposition. Multiple high-refractive-index and low-refractive-index films are deposited alternately to form a color layer. When light passes through the color layer, it is decomposed into multiple monochromatic lights, giving the optical lens color.
[0045] The material that can be used to form the high refractive index film can be any one of titanium pentoxide, zirconium dioxide, or tantalum pentoxide. The material that can be used to form the low refractive index film can be any one of silicon dioxide or aluminum oxide. In this embodiment, the high refractive index film is made of titanium pentoxide, and the low refractive index film is made of silicon dioxide.
[0046] High-refractive-index film layers and low-refractive-index film layers can be alternately configured in multiple layers. Considering that too many layers will increase the total thickness of the coating, thereby increasing the risk of coating peeling and cracking, in this embodiment, both high-refractive-index film layers and low-refractive-index film layers are alternately configured in three layers.
[0047] The three high-refractive-index films are designated as the first high-refractive-index film, the second high-refractive-index film, and the third high-refractive-index film, respectively, from near to far from the substrate. The three low-refractive-index films are designated as the first low-refractive-index film, the second low-refractive-index film, and the third low-refractive-index film, respectively, from near to far from the substrate.
[0048] In this embodiment, each high-refractive-index film layer and each low-refractive-index film layer are configured within a specific thickness range. For example, the thickness of the first high-refractive-index film layer is 80-100 nm, the thickness of the second high-refractive-index film layer is 70-90 nm, and the thickness of the third high-refractive-index film layer is 70-90 nm. Similarly, the thickness of the first low-refractive-index film layer is 80-100 nm, the thickness of the second low-refractive-index film layer is 70-90 nm, and the thickness of the third low-refractive-index film layer is 70-90 nm. This thickness difference allows the optical lens to exhibit low reflectivity and excellent optical transparency in the visible light range, while also presenting the desired neutral color appearance.
[0049] During the vapor deposition process of high-refractive-index and / or low-refractive-index films, an ion-assisted deposition source is activated. The ion-assisted deposition source generates an ion wind, which continuously bombards the forming film, making the atomic deposition within the film compact and reducing the porosity within the film, thereby improving the density and adhesion of the high-refractive-index and / or low-refractive-index films.
[0050] After the color layer is deposited on the substrate surface, the substrate is immersed in the test reagent and taken out after a period of time to observe the integrity of the coating. If the coating is intact, it is a good product.
[0051] In practice, the test reagent is a saline-chlorine solution formed by mixing a 3.5% saline solution and a 50ppm chlorine solution.
[0052] Fifty substrates from the same batch, after coating, were immersed in a saline-chlorine solution for 48 hours. After removal, the 50 samples were tested, and 35 samples were found to be... Figure 4 The good products shown are the coatings of the 5 samples. Figure 2As shown, the coating peeled off the substrate in 10 samples, exhibiting the following characteristics: Figure 3 The varying degrees of cracking shown indicate a yield rate of 70%.
[0053] Example 2
[0054] To improve the yield rate of optical lenses after coating, a stress testing process is provided in a preferred embodiment of this application. The stress testing process is performed after the color layer has been deposited by vapor deposition, and is used to test the stress in the high-refractive-index and low-refractive-index layers within the color layer.
[0055] The addition of this step is based on the following considerations:
[0056] Theoretically, ion-assisted deposition sources improve the density and adhesion of the color layer through ion wind. Simultaneously, the bombardment of the ion wind forces surface atoms into the interior of the film, increasing its density and compressing its volume. Furthermore, because the film is firmly attached to the substrate and cannot shrink freely, enormous compressive stress is generated internally.
[0057] When applied to high-refractive-index and low-refractive-index films, the difference in material properties results in varying degrees of internal stress. Taking titanium pentoxide as the high-refractive-index film and silicon dioxide as the low-refractive-index film in this application as examples:
[0058] Titanium pentoxide is an oxide with certain metallic properties, and its crystal structure allows for some slip between atomic layers. Its chemical bonds are a mixture of ionic and metallic bonds, a bonding method that possesses a degree of ductility and plasticity. Therefore, after atoms are deposited onto the substrate, they have a large relaxation space to release stress. Consequently, even with the assistance of an ion source, its internal stress is relatively low.
[0059] Silica has a covalent network structure, where atoms are strongly bonded together to form a robust yet disordered three-dimensional network. However, this network structure lacks the ability to undergo plastic deformation, making it difficult for atoms to move or rearrange to release stress. Microscopic strains caused by external forces are confined within this network structure, resulting in high internal stress in the film.
[0060] Based on experimental findings, defects on lenses typically manifest as coating cracking or detachment from the substrate. It is inferred that coating cracking is likely caused by differences in internal stress between the film layers. Therefore, this application verifies the possible causes of lens defects by adding an internal stress testing process.
[0061] The internal stress testing procedure includes: performing internal stress tests on the high-refractive-index film layer and the low-refractive-index film layer respectively, and obtaining the first internal stress of the corresponding high-refractive-index film layer and the second internal stress of the corresponding low-refractive-index film layer respectively. The internal stress testing method can employ either the substrate curvature method or X-ray diffraction.
[0062] Furthermore, based on the difference between the first internal stress and the second internal stress, the ion-assisted deposition source is selectively activated during one of the deposition processes of the high-refractive-index film layer and the low-refractive-index film layer, or the power of the ion-assisted deposition source is changed during the other deposition process, so that the difference between the first internal stress and the second internal stress is reduced after deposition is completed, thereby reducing coating defects caused by the difference in stress between film layers.
[0063] In this embodiment, internal stress tests were performed on the thickest first high-refractive-index film and the first low-refractive-index film, respectively. The results showed that the first internal stress of the first high-refractive-index film was 70 MPa, and the second internal stress of the first low-refractive-index film was 600 MPa. Accordingly, when depositing the high-refractive-index film, the anolyte voltage of the ion-assisted deposition source was maintained at 130–140 V, the anolyte current at 2–3 A, the oxygen flow rate at 10–25 sccm, and the argon flow rate at 0–10 sccm. When depositing three low-refractive-index films, the ion-assisted deposition source and argon flow rate were adjusted. The specific parameters after adjustment were as follows: the anolyte voltage was reduced to 110–125 V, the anolyte current was reduced to 1.5–2.2 A, and the argon flow rate was reduced to 0–5 sccm.
[0064] The internal stress of the coating with the adjusted ion-assisted deposition source was tested, and the first internal stress corresponding to the first high refractive index film layer was found to be 70 MPa, while the second internal stress corresponding to the first low refractive index film layer was reduced to 400 MPa.
[0065] Fifty optical lenses coated using an adjusted ion-assisted deposition source were prepared and immersed in a test reagent for 48 hours. The test reagent consisted of a 3.5% saline solution and a 50 ppm chlorine solution. After removal, the 50 samples were tested. 45 samples were found to be good, 4 samples showed coating detachment from the substrate, and 1 sample showed coating cracking, resulting in a yield rate of 90%.
[0066] Example 3
[0067] Based on Example 2, the ion-assisted deposition source was completely turned off when depositing low-refractive-index films, and was turned on only when depositing high-refractive-index films, with the relevant parameters set as follows: argon flow rate of 0-20 sccm, anodic voltage of ion activation source of 80-100 V, and anodic current of 2-3 A.
[0068] The internal stress of the coating with the adjusted ion-assisted deposition source was tested, and the first internal stress corresponding to the first high refractive index film layer was found to be 60 MPa, and the second internal stress corresponding to the first low refractive index film layer was 350 MPa.
[0069] Fifty optical lenses coated using an adjusted ion-assisted deposition source were prepared and immersed in a test reagent for 48 hours. The test reagent consisted of a 3.5% saline solution and a 50 ppm chlorine solution. After removal, the 50 samples were tested. 47 samples were found to be good, and the coating on 3 samples detached from the substrate. No coating cracking was observed on the samples, resulting in a yield rate of 94%.
[0070] Therefore, combining this embodiment with Embodiments 1 and 2 above, it can be confirmed that the causes of defects in optical lenses include at least a large difference in internal stress between different film layers within the color layer. By reducing the difference in internal stress between different film layers, the phenomenon of coating cracking can be reduced very effectively.
[0071] The reduction in coating detachment from the substrate is attributed to the fact that a significant decrease in the initial internal stress of the low-refractive-index film weakens its tensile or compressive stress coupling effect on adjacent high-refractive-index films. This stress decoupling effectively reduces micro-bending or lattice distortion induced in the high-refractive-index film. Consequently, the initial internal stress of the high-refractive-index film attached to the substrate via the bonding layer also tends to decrease, resulting in better stress compatibility across the entire color layer.
[0072] This change gives the high-refractive-index film a better elastic deformation range when responding to microscopic deformations of the substrate caused by changes in external environment such as temperature and humidity. Therefore, the film is less likely to generate shear stress on the adhesion surface due to deformation mismatch with the substrate, thereby improving the adhesion stability between the film and the substrate and reducing the risk of detachment.
[0073] The above embodiments are merely illustrative of the technical concept and features of the present invention, intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and should not be construed as limiting the scope of protection of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of the present invention is defined by the appended claims rather than the foregoing description, and thus all changes falling within the meaning and scope of the equivalents of the claims are intended to be included within the present invention.
Claims
1. A coating process for manufacturing an optical lens comprising a substrate, characterized in that, The coating process comprises: Preparation of the substrate and the vacuum chamber, including: before the substrate is put into the vacuum chamber, pre-treatment of the substrate by an ion cleaning source, including cleaning and destaticizing; adjusting the temperature and vacuum degree of the vacuum chamber to reach the first preset interval and the second preset interval respectively; The substrate is put into the vacuum chamber, and the substrate is deeply cleaned and surface-activated by an ion activation source; In the vacuum chamber, the surface of the substrate is sequentially deposited with high refractive index film layers and low refractive index film layers by evaporation, and the color layer is formed by the alternately deposited high refractive index film layers and low refractive index film layers; meanwhile, the ion assisted deposition source is used to improve the compactness and adhesion of the high refractive index film layers and the low refractive index film layers; The substrate coated with the color layer is immersed in a detection reagent, taken out after a preset time interval, and the integrity of the coating is detected; The coating process comprises internal stress testing: the high refractive index film layers and the low refractive index film layers are respectively subjected to internal stress testing, and the first internal stress corresponding to the high refractive index film layers and the second internal stress corresponding to the low refractive index film layers are obtained; Based on the difference between the first internal stress and the second internal stress, the ion assisted deposition source is selectively turned on during the deposition of one of the high refractive index film layers and the low refractive index film layers, or the power of the ion assisted deposition source is changed during the deposition of the other, so that the difference between the first internal stress and the second internal stress is reduced after the deposition is completed.
2. A coating process for manufacturing an optical lens according to claim 1, characterized in that, A bonding layer is formed between the substrate and the color layer by evaporation, and the bonding layer is used to increase the adhesion between the color layer and the substrate; the material forming the bonding layer is any one of silicon monoxide, aluminum trioxide and chromium.
3. A coating process for manufacturing an optical lens according to claim 1, characterized in that, The material forming the high refractive index film layers can be any one of titanium trioxide, zirconium dioxide and tantalum pentoxide; The material forming the low refractive index film layers can be any one of silicon dioxide and aluminum oxide.
4. A coating process for manufacturing an optical lens according to claim 1, characterized in that, The high refractive index film layers are arranged as three in the color layer, including the first high refractive index film layer, the second high refractive index film layer and the third high refractive index film layer gradually away from the substrate; The low refractive index film layers are arranged as three in the color layer, including the first low refractive index film layer, the second low refractive index film layer and the third low refractive index film layer gradually away from the substrate.
5. A coating process for manufacturing an optical lens according to claim 4, characterized in that, The thickness of the first high refractive index film layer is 80-100 nm, the thickness of the second high refractive index film layer is 70-90 nm, and the thickness of the third high refractive index film layer is 70-90 nm; The thickness of the first low refractive index film layer is 80-100 nm, the thickness of the second low refractive index film layer is 70-90 nm, and the thickness of the third low refractive index film layer is 70-90 nm.
6. A coating process for manufacturing an optical lens according to claim 1, characterized in that, The anode voltage of the ion assisted deposition source is set to 130-140 V, the anode current is set to 2-3 A, the oxygen flow is set to 10-25 sccm, and the argon flow is set to 0-10 sccm.
7. A coating process for manufacturing an optical lens according to claim 1, characterized in that, The first preset interval is set to 45-65℃, and the second preset interval is set to 3.0x10 -5 -5.0x10 -5 mbar.
8. A coating process for manufacturing an optical lens according to claim 1, characterized in that, The anode voltage of the ion activation source is set to 80-100 V, the anode current is set to 2-3 A, and the argon flow is set to 0-20 sccm.
9. A coating process for manufacturing an optical lens according to claim 1, characterized in that, The detection reagent is a salt-chlorine water solution prepared by using salt water with a concentration of 3.5% and chlorine water with a concentration of 50 ppm; the preset time is set to 24-72 h.