Film and lens for vision correction

Abstract

The present invention relates to the field of lens technology, and in particular to a film and lens for vision correction. The film for vision correction is deposited on the surface of a lens substrate, comprising a refractive index matching layer, a refractive compensation layer, a defocus prevention and control layer, an anti-blue light interference layer and a super-hydrophobic wear-resistant layer arranged in sequence from bottom to top; the refractive compensation layer covers the entire aperture and forms an optical zone for refractive correction in the central area, and the film thickness of the refractive compensation layer decreases from the center to the edge; the defocus prevention and control layer covers an annular area around the optical zone, including an annular transition zone and a main defocus area extending outward from the outer edge of the annular transition zone; the defocus prevention and control layer is composed of a ZrO2-epoxy resin composite; the film thickness in the annular transition zone increases linearly from the inside to the outside, and a radial electric field is induced to gradually change the concentration of ZrO2 nanoparticles to form a radial gradient of refractive index, the concentration of ZrO2 nanoparticles in the main defocus area is constant, and the peripheral defocus is maintained by a secondary increase in film thickness.

Description

Technical Field

[0001] The present invention relates to the technical field of lenses, and in particular to a film and a lens for vision correction. Background Art

[0002] In recent years, with the rapid rise in myopia incidence and the diversification of consumer demands for visual health, vision correction lenses have gradually evolved from a single refractive compensation function to a multi-dimensional integrated function of "correction, prevention, and protection." Traditional lens technology, centered around monofocal or progressive multifocal designs, achieves precise correction of refractive power in the primary visual area by machining specific curvatures on the lens substrate surface. Its mature optical design theory can meet basic vision correction needs. However, the design logic of such lenses prioritizes clarity in the primary visual area as the sole optimization goal, ignoring the regulatory effect of peripheral retinal defocus signals on axial length growth, making it difficult to simultaneously address myopia prevention and control.

[0003] To this end, new prevention and control lenses based on peripheral defocus theory are gradually emerging. For example, by placing microlens arrays or defocus rings in the peripheral area of ​​the lens, the defocus signal is used to suppress excessive elongation of the eye axis. Existing research shows that this design can reduce the risk of myopia progression by approximately 30%. However, the microlens array requires discrete defocus units formed through precision etching or nanoimprinting, which is not only expensive to manufacture, but the defocus amount is easily affected by random fluctuations in the film thickness, resulting in unstable defocus signal intensity.

[0004] Furthermore, in the prior art, the discrete defocusing units and the main visual area refractive compensation structure are mostly designed with physical stacking or regional discreteness, resulting in limited degrees of freedom of the optical system. For example, progressive multifocal lenses achieve far-to-near vision transitions through continuous curvature changes, but their defocusing amount is limited by a fixed curvature gradient and cannot adapt to the user's dynamic adjustment needs; while the defocusing amount of the microlens array is completely determined by the lens height, lacking the ability to dynamically adapt based on eye movement characteristics, making it difficult to balance the contradiction between defocus prevention and control strength and visual comfort. In addition, the physical separation of the discrete defocusing units and the main visual area refractive compensation structure may cause stray light interference, resulting in a decrease in visual contrast and an increase in dizziness, affecting user compliance.

[0005] The essence of these technical bottlenecks lies in the fact that traditional lens design treats functions such as refractive correction, defocus control, and surface protection as independent modules for local optimization, ignoring the systemic contradictions arising from the synergistic effects of multiple film layers. Therefore, establishing a synergistic optimization mechanism for refractive correction accuracy, dynamic defocus adaptability, and film interface stability within a single film system has become a core challenge in the field of myopia prevention and control lenses.

[0006] The information disclosed in this background technology section is only intended to deepen the understanding of the overall background technology of the present invention and should not be regarded as an admission or any form of suggestion that the information constitutes the prior art known to those skilled in the art. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a film for vision correction, which can achieve efficient synergy between refractive correction and myopia prevention and control functions, while taking into account the stability of optical performance, dynamic adaptability of defocus and interface compatibility between multiple film layers.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is:

[0009] A thin film for vision correction, deposited on the surface of a lens substrate, comprising, from bottom to top, a refractive index matching layer, a refractive compensation layer, a defocus prevention layer, a blue light interference layer, and a super-hydrophobic wear-resistant layer;

[0010] The refractive index matching layer, refractive compensation layer, blue light interference layer and super hydrophobic wear-resistant layer all cover the entire aperture of the substrate;

[0011] The refractive compensation layer forms an optical zone for refractive correction in the central area, and the film thickness of the refractive compensation layer decreases from the center to the edge;

[0012] The defocus prevention and control layer covers the annular area around the optical zone, including the annular transition zone and the main defocus area extending outward from the outer edge of the annular transition zone;

[0013] The defocus control layer is composed of a ZrO2-epoxy resin composite; the film thickness in the annular transition zone increases linearly from the inside to the outside, and the concentration of ZrO2 nanoparticles is induced to decrease from the inside to the outside through a radial electric field, forming a radial gradient of refractive index. The concentration of ZrO2 nanoparticles in the main defocus area is constant, and the peripheral defocus is maintained by a secondary increase in film thickness.

[0014] The annular transition zone of the defocus prevention and control layer of the present invention induces a concentration gradient distribution of ZrO2 nanoparticles through a radial electric field, so that the defocus amount can continuously change along the radial direction of the lens, forming a defocus gradient field that matches the natural adjustment state of the eyeball, and guiding the eyeball to adapt to the gradient change. When the user's eyeballs rotate, the defocus signal is dynamically adjusted along the direction of the visual axis, which not only avoids the visual adaptation fatigue caused by the fixed defocus amount, but also provides differentiated defocus stimulation for retinal areas with different pupil diameters, thereby achieving a balance between prevention and control effect and wearing comfort. The main defocus area is fixedly defocused, corresponding to the blind spot that the eyeball rarely actively looks at. A high-intensity, continuous peripheral defocus signal is provided by fixing the defocus amount. Ensure that the periphery of the retina is always in a defocus state of "inhibiting axial growth" to avoid signal attenuation caused by dynamic changes.

[0015] Preferably, the refractive index matching layer is a 3-5 layer composite film layer formed by alternately depositing SiO2 / Al2O3 on the surface of the lens substrate; the thickness of the refractive index matching layer is 0.5-1.2 μm, and the refractive index gradient Δn≤0.005.

[0016] Specifically, the alternating stacking of SiO2 (with a refractive index of approximately 1.46) and Al2O3 (with a refractive index of approximately 1.76) creates a gradual refractive index transition through the difference in refractive indices between the two materials. The chemical bonding between the alternating layers enhances film density and inhibits the propagation of microcracks. The number of layers can be optimized to balance process complexity and optical performance. Three layers can cover the anti-reflection requirements of the visible light band, while five layers can extend to the near-infrared band, adapting to the wide spectral compatibility of the blue light protection layer.

[0017] Preferably, the refractive index gradient of the refractive index matching layer is orthogonal to the thickness gradient of the refractive compensation layer, adapting to different substrate curvatures. The thickness gradient of the refractive compensation layer is arranged along the radial direction of the lens, with the film thickness decreasing from the optical center to the edge to achieve refractive correction. The refractive index gradient is tangential to the lens substrate. A dynamic mask combined with substrate translation is used. By linearly moving the light-shielding mask, such as by gradually changing the slit width, the deposition ratio of SiO2 / Al2O3 is controlled to gradually change tangentially. Specifically, when alternately sputtering SiO2 / Al2O3, the substrate is stepped along the tangential direction, switching targets every 1mm, achieving a spatial gradient of the SiO2 / Al2O3 film composition ratio, forming a refractive index gradient of Δn ≤ 0.005 / mm.

[0018] Preferably, the refractive compensation layer is fluorine-doped zinc oxide with a thickness of 5 to 15 μm. The difference between the refractive index of the top layer of the refractive index matching layer and the refractive index of the refractive compensation layer is ≤0.05, so as to avoid interface reflection loss and excessive stress in the film layer. Specifically, the thickness of the refractive compensation layer is the largest at the center, which is 15 μm. Extending outward in its radial direction, the thickness of the refractive compensation layer gradually decreases, and the film structure formed with a thick center and a thin edge is equivalent to the curvature of a concave lens, thereby achieving precise refractive correction. After the defocus control layer is covered, the ZrO2-epoxy resin composite and concentration gradient design of the defocus control layer are simultaneously used to form a dynamically adapted peripheral defocus area, taking into account both the clarity of the main visual area and the defocus control effect.

[0019] Preferably, the preparation method of the defocus prevention and control layer includes:

[0020] S1: forming a ZrO2-epoxy resin composite base film layer on the surface of the refractive compensation layer by spin coating, with a thickness of 1.0-1.5 μm and a ZrO2 mass fraction of 25-35%;

[0021] Preferably, the spin coating solution of the ZrO2-epoxy resin composite comprises, calculated by weight:

[0022] Epoxy resin: 30-40 parts;

[0023] ZrO2 nanoparticles: 5-35 parts;

[0024] Propylene glycol methyl ether acetate: 30-40 parts;

[0025] Photoinitiator: 1~5 parts;

[0026] Dispersant: 0.5~1 part;

[0027] Defoaming agent: 0.1~0.3 parts;

[0028] ZrO2 nanoparticles with a particle size of 10-50 nm were surface-modified with 1 wt% silane coupling agent. Specifically, the ZrO2 nanoparticles were dispersed in anhydrous ethanol to a controlled solids content of 10% and ultrasonically treated for 30 minutes. KH-550 (1 wt% by weight of the ZrO2 mass) was then added dropwise and stirred at 60°C for 4 hours. The mixture was then centrifuged at 8000 rpm for 10 minutes, washed three times with ethanol, and dried under vacuum at 80°C. The epoxy resin was either bisphenol A or a cycloaliphatic epoxy resin. During the process, the silane-coupling-modified ZrO2 nanoparticles formed a stable suspension with the epoxy resin in a solution containing a dispersant, preventing particle sedimentation or agglomeration during spin coating. The high-speed spin-coating solution then spreads into a film, generating centrifugal force. After solvent evaporation, a uniform substrate with a thickness of 1.0-1.5 μm is formed. In the present invention, the dispersant is a silane coupling agent added to the formula, preferably BYK-111, which prevents the pre-modified ZrO2 from secondary agglomeration in the epoxy resin and maintains long-term dispersion stability.

[0029] S2: applying a radial electric field in the uncured base film layer, and forming a radial ZrO2 concentration gradient decreasing from the inside to the outside and an increasing film thickness through the synergistic effect of electrophoretic migration and centrifugal force;

[0030] S3: Define an annular transition zone with a width of 3.0-4.5 mm, and use the edge of the annular transition zone as the starting point of the main defocus zone. Compensate the ZrO2 concentration in the main defocus zone through secondary dynamic spraying to maintain a constant concentration, and increase the film thickness of the main defocus zone. The maximum film thickness at the edge of the main defocus zone is ≤25 μm.

[0031] The present invention sprays a composite liquid containing ZrO2 in the main body defocus area to compensate for the concentration at the outer edge of the annular transition zone and eliminate concentration fluctuations caused by electric field migration; during the process, the nozzle moves radially, and the spraying rate increases linearly with the radial position, so that the film thickness increases from 3μm to 25μm.

[0032] S4: UV curing locks the gradient structure to form a cross-linked and cured defocus prevention layer. The film thickness uniformity error after curing is ≤±1.5%.

[0033] Among them, ultraviolet light excites the photoinitiator, which triggers the free radical polymerization of epoxy resin to form a three-dimensional cross-linked network to fix the gradient distribution of ZrO2.

[0034] The composite system of ZrO2 nanoparticles and epoxy resin in the defocus control layer of the present invention enhances the inorganic-organic interface bonding force through the dual effects of chemical bonding and physical entanglement, solves the peeling problem caused by the difference in thermal expansion coefficient between the traditional hard oxide film layer and the resin substrate, and significantly improves the durability of the film layer.

[0035] Preferably, in step S2, the outer edge electrode is connected to a negative high-voltage power supply, the center electrode is grounded, and the electric field intensity decreases linearly from the outer edge to the center to 0 kV / mm in the radial direction; at this time, the ZrO2 nanoparticles are positively charged and migrate toward the center of the lens under the drive of the radial electric field, forming a concentration gradient that gradually decreases from the center to the edge; when the base film layer is not solidified, the centrifugal force causes the resin phase to flow toward the outer edge, resulting in a film thickness increase from 1.0 μm in the center to 1.5 μm at the edge. The present invention achieves a "decreasing concentration-increasing film thickness" dual gradient by directing particle migration with the electric field and regulating the film thickness distribution with the centrifugal force, and the orthogonal effects of the two achieves.

[0036] Preferably, in step S2, the electrode spacing is 0.1-0.5 mm. The electric field lines are more densely distributed and uniform, ensuring that the electrophoretic migration path of the ZrO2 nanoparticles in the radial direction is highly controllable. At an extremely narrow spacing, the inter-electrode voltage only needs 50-1500 V to achieve a high field strength of 5 kV / mm, without the need for a high-voltage power supply, avoiding the risk of insulation breakdown. Preferably, at a spacing of 0.1 mm, the linear decreasing slope error of the electric field intensity along the radial direction is less than ±2%, providing a precise driving force for the ZrO2 concentration gradient.

[0037] Preferably, in step S3, during dynamic spraying, the ZrO2 mass fraction is consistent with the edge concentration of the annular transition zone, compensating for concentration fluctuations in the main defocus region due to electric field migration or centrifugal diffusion, ensuring a constant ZrO2 mass fraction in the main region. Dynamic spraying utilizes a multi-nozzle array moving radially, with adjacent nozzle trajectories overlapping by 50%. Staggered spray paths eliminate film thickness fluctuations, and the nozzle movement speed is 20-40 mm / s. Through secondary spraying, the film thickness in the main defocus region is distributed according to a quadratic function Q(r) = 0.06(r-r0)^2 + 1.5 (mL / min). This quadratic function simulates the nonlinear growth of peripheral defocus during natural eye accommodation, with a curvature of 0.06 adapted to the spatial distribution of peripheral retinal defocus sensitivity. The spray flow rate Q(r) increases with radial position r, and the film thickness accumulation rate is positively correlated with the required defocus, achieving a linear conversion between film thickness and defocus.

[0038] Preferably, in step S4, UV curing is performed under a nitrogen atmosphere. Nitrogen displacement eliminates oxygen inhibition, improving cure depth and crosslink density. The curing temperature is 35-45°C. This reduces resin viscosity, promotes leveling of the uncured layer, and reduces film thickness uniformity. Furthermore, low-temperature curing reduces resin shrinkage stress, preventing film cracking or delamination from the refractive compensation layer.

[0039] Preferably, the anti-blue light interference layer is a 9-15 layer structure of alternately deposited TiO2 / SiO2, the thickness of the TiO2 single layer in the anti-blue light interference layer is 10-30 nm, the thickness of the SiO2 single layer is 50-100 nm, the total thickness is 1.5-2.5 μm, the average transmittance in the light transmission band is ≥95%, and the 455 nm blue light cutoff rate is ≥92%.

[0040] In this invention, high-refractive-index TiO2 and low-refractive-index SiO2 are stacked alternately in 9-15 layers, creating a broad-spectrum destructive interference in the blue light band (400-500nm). Because interference conditions are not met in other bands, transmittance is ≥95%, ensuring visual clarity. The total thickness is controlled at 1.5-2.5μm to avoid stress cracking caused by excessive thickness, ensuring long-term stability and compatibility with lightweight lenses.

[0041] Preferably, the super-hydrophobic, wear-resistant layer is a diamond-like carbon (DLC) or modified fluorosilane coating, with a water contact angle ≥115° and a pencil hardness ≥9H. Diamond-like carbon (DLC) is suitable for glass lenses and hard resin lenses. The present invention prefers a modified fluorosilane coating, which is an organic monolayer formed by chemical self-assembly or solution deposition. The hardness and wear resistance of the fluorosilane coating can be significantly improved by introducing SiO2 nanoparticles (10-50nm) or Al2O3 nanowhiskers.

[0042] The second purpose of the present invention is to provide a lens for vision correction, which uses the above-mentioned film for vision correction to solve the technical contradiction that traditional lenses are difficult to simultaneously optimize the vision correction effect, myopia progression inhibition ability and functional film layer superposition adaptability.

[0043] In order to achieve the above object, the technical solution adopted by the present invention is:

[0044] A lens for vision correction uses the above-mentioned film for vision correction, comprising a lens substrate, the film being arranged on the side of the lens substrate away from the eyes, and an anti-fatigue filter film being arranged on the side of the lens substrate facing the eyes.

[0045] Preferably, the lens substrate is made of resin or glass material, the front surface curvature radius R1 of the lens substrate is 50~200mm, suitable for plano to high myopia / hyperopia, the back surface curvature radius R2 is 30~150mm to reduce edge aberration and avoid visual field distortion, and the center thickness is 1.0~8.0mm.

[0046] Preferably, the front surface of the lens substrate is provided with an annular micro-groove structure with a V-shaped or trapezoidal cross-section, which reduces the internal stress concentration during coating curing and improves the mechanical bite force between the film layer and the substrate. The groove depth is 5~15μm, the width is 20~0μm, the spacing is 100~200μm, and the surface roughness is Ra=0.1~0.5μm. The rough surface forms nano-scale bumps and grooves, which increases the contact area of ​​the film layer and is used to enhance the adhesion of the refractive index matching layer.

[0047] In this invention, a thin film on the front surface of the lens substrate, located away from the eye, achieves vision correction. The anti-fatigue filter coating on the rear surface near the eye comprises SiO2 / TiO2 / SiO2 / MgF2, arranged in sequence from the inside out. This complements the defocus control layer and blue light protection layer on the other side, creating a front-to-back functional complementarity that covers all eye needs. In the anti-fatigue filter, the inner SiO2 layer has a refractive index close to that of the resin / glass substrate, reducing interfacial reflections. Its low stress alleviates the high-pressure stress of the TiO2 layer, preventing cracking. The TiO2 middle layer, designed with a quarter-wavelength thickness, achieves destructive interference, reflecting harmful blue light from 430-455nm. The low refractive index gradient of the outer SiO2 / MgF2 layer prevents refractive index abrupt changes between film layers, reducing the final average surface reflectivity. The lens provides medical-grade protection against the harmful blue light from mainstream electronic screens, while also alleviating accommodation fatigue through enhanced red light transmission, making it suitable for over 90% of everyday scenarios.

[0048] Preferably, the equivalent defocus of the lens is +2.50D to +4.00D. Through the positive defocus design of the peripheral area, the growth of the eye axis is delayed and the development of myopia is controlled. The central optical zone maintains zero defocus to ensure clear imaging of the fovea of ​​the retina. The transmittance is ≥98%, the stray light intensity is ≤0.6%, and the glare and ghosting caused by internal reflection and surface scattering of the lens are suppressed, thereby improving visual comfort.

[0049] The beneficial effects of the present invention are:

[0050] (1) The present invention forms a precise refractive correction capability in the optical zone through the structure of the central film thickness decreasing of the refractive compensation layer, and at the same time uses the annular transition zone of the defocus control layer and the main defocus zone to construct a dynamically adaptive defocus signal field around the optical zone. The concentration gradient of ZrO2 nanoparticles in the annular transition zone makes the refractive index transition smoothly along the radial direction, avoiding the stray light and glare problems caused by the defocus unit of the traditional discrete microlens array; the main defocus zone maintains a stable defocus amount without relying on the addition of additional materials through the secondary increasing film thickness design, thereby ensuring the imaging clarity of the main visual area while providing continuous defocus stimulation to the peripheral area of ​​the retina, effectively inhibiting the excessive growth of the eye axis. The dual optimization of vision correction and myopia prevention and control is achieved.

[0051] (2) The present invention introduces a refractive index matching layer to establish a refractive index transition bridge between the substrate and the refractive compensation layer, significantly reducing interlayer Fresnel reflection loss and avoiding ghosting and flare phenomena. The anti-blue light interference layer and the super-hydrophobic wear-resistant layer adopt an independent functional layering strategy. The two do not interfere with each other in space and function, ensuring the blue light protection effect while maintaining the surface hydrophobicity and wear resistance. In addition, the introduction of the super-hydrophobic wear-resistant layer not only reduces the adhesion rate of stains on the lens surface, but also extends the service life of the functional film layer by reducing friction damage during wiping, ensuring long-term stable output of the defocus signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 A top view of the film for vision correction of the present invention;

[0053] Figure 2 A flow chart for the preparation of lenses for vision correction;

[0054] Figure 3 This is a process flow chart for preparing the defocus prevention and control layer;

[0055] Figure 4 Diagram of the gradient formation mechanism of the defocus control layer;

[0056] Attached figures: 01, ZrO2 nanoparticle induction direction; 02, resin movement direction; 03, secondary dynamic spraying compensation direction; 10, lens substrate; 20, thin film for vision correction; 30, anti-fatigue filter film; 11, annular micro-groove structure; 21, refractive index matching layer; 22, refractive compensation layer; 23, defocus control layer; 24, anti-blue light interference layer; 25, super hydrophobic wear-resistant layer; 26, optical zone; 231, annular transition zone; 232, main body defocus zone. DETAILED DESCRIPTION

[0057] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0058] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification are for the purpose of describing specific embodiments only and are not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0059] The raw materials or reagents used in the Examples of the present invention and / or the Comparative Examples are all purchased from mainstream manufacturers in the market. If the manufacturer is not specified or the concentration is not specified, they are all analytically pure raw materials or reagents that can be routinely obtained. As long as they can play the expected role, there are no special restrictions. The instruments and equipment used in this embodiment are all purchased from major manufacturers in the market. As long as they can play the expected role, there are no special restrictions. If specific techniques or conditions are not specified in this embodiment, they are carried out according to the techniques or conditions described in the literature in this area or according to the product specifications.

[0060] Table 1

[0061]

[0062] Example 1: Spin coating solution of preferred ZrO2-epoxy resin composite

[0063] The spin coating solution of the ZrO2-epoxy resin composite includes the following components in parts by mass:

[0064] Epoxy resin: 30-40 parts; ZrO2 nanoparticles: 5-35 parts; Propylene glycol methyl ether acetate: 30-40 parts; Photoinitiator: 1-5 parts; Dispersant: 0.5-1 parts; Defoamer: 0.1-0.3 parts;

[0065] ZrO2 nanoparticles with a particle size of 10-50 nm were surface-modified with 1 wt% silane coupling agent. Specifically, the ZrO2 nanoparticles were dispersed in anhydrous ethanol to a solids content of 10% and ultrasonically treated for 30 minutes. KH-550 (1 wt% by weight of the ZrO2 mass) was added dropwise and stirred at 60°C for 4 hours. The mixture was then centrifuged at 8000 rpm for 10 minutes, washed three times with ethanol, and dried under vacuum at 80°C. The surface-modified ZrO2 was then ground and sieved to obtain surface-grafted amino groups. The epoxy resin used was either bisphenol A or a cycloaliphatic epoxy resin. During the process, the silane-coupling-modified ZrO2 nanoparticles formed a stable suspension with the epoxy resin in a solution containing a dispersant, preventing particle sedimentation or agglomeration during spin coating. The spin-coated solution was then spread to form a film using centrifugal force generated by high-speed rotation at at least 3000 rpm. After solvent evaporation, a uniform substrate with a thickness of 1.0-1.5 μm was formed.

[0066] As shown in Table 2 below, by comparing spin-coating fluid formulations with varying ZrO2 nanoparticle content, epoxy resin type, and solvent ratio, we identified the formulation with the best adhesion, defocus accuracy, transmittance, and wear resistance. The spin-coating fluid was prepared by mixing epoxy resin and propylene glycol methyl ether acetate in a planetary mixer at 500 rpm for 10 minutes. The pre-modified ZrO2 was then slowly added, gradually increasing the speed to 2000 rpm for 30 minutes. A photoinitiator, dispersant, and defoamer were added, and the mixture was mixed at 1000 rpm for 20 minutes before vacuum degassing.

[0067] Table 2

[0068]

[0069] Note: The alicyclic epoxy resin is 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexylcarboxylate.

[0070] The prepared spin coating liquid was used for dynamic gradient film formation, wherein a CR-39 resin substrate with a diameter of 70 mm and a curvature radius of R = 100 mm was fixed on a spin coater. After surface pretreatment, 5 mL of the spin coating liquid was added, and then the substrate was first spun at a low speed of 500 rpm / 10 seconds; then spun at a high speed of 3000 rpm / 30 seconds; then a radial electric field gradient was applied; and finally, UV curing was performed.

[0071] Table 3 below shows the spin coating test results of the above-mentioned multiple experiments. Adhesion was tested using the cross-hatch method (ASTM D3359), with a rating of 1B (worst) to 5B (best). Defocus accuracy was measured using a wavefront aberrometer (ZYGO Verifire) to measure the equivalent defocus error (target ±0.25D). Transmittance was measured using a spectrophotometer (PerkinElmer Lambda 950) to measure the transmittance at 550 nm. Wear resistance was measured using the Taber abrasion test (CS-10 wheel, 500 cycles) to determine film thickness retention. Dispersion stability was measured using the ZrO2 sedimentation rate (upper / lower layer concentration difference) after the spin-coated solution was allowed to stand for 24 hours.

[0072] Table 3

[0073]

[0074] The above data show that Examples 1-5, 1-6, and 1-7 demonstrate the impracticality of unmodified or overloaded formulations. In Example 1-3, the low viscosity of the alicyclic resin allows for a more precise electric field-induced gradient, synergistically acting with the silane coupling agent to achieve optimal ZrO2 dispersion and close resin-particle interface bonding. Furthermore, the low-temperature curing properties of the alicyclic epoxy resin are compatible with the resin substrate, meeting the design requirements of high-precision defocus control lenses. Therefore, in subsequent designs, the components of Example 3 are preferred, i.e., the spin-coating solution of the ZrO2-epoxy resin composite, calculated by weight, includes: 38 parts alicyclic epoxy resin; 30 parts ZrO2 nanoparticles; 30 parts propylene glycol methyl ether acetate; 3 parts photoinitiator; 1 part dispersant; and 0.2 parts defoamer.

[0075] Example 2

[0076] like Figures 1 to 4The lens shown is for vision correction, comprising a lens substrate 10 and a film 20 for vision correction arranged on the side of the lens substrate 10 away from the eye. An anti-fatigue filter film 30 is also arranged on the side of the lens substrate 10 facing the eye.

[0077] Specifically, the lens substrate 10 is made of resin or glass. It should be noted that the resin substrate may be CR-39 or polycarbonate. The front surface curvature radius R1 of the lens substrate 10 is 50-200 mm, suitable for plano to high myopia / hyperopia. The back surface curvature radius R2 is 30-150 mm to reduce peripheral aberrations and prevent visual field distortion. The center thickness is 1.0-8.0 mm.

[0078] The front surface of the lens substrate 10 is provided with an annular micro-groove structure 11. The annular micro-groove structure 11 has a V-shaped or trapezoidal cross-section, which reduces the internal stress concentration during coating curing and improves the mechanical bite force between the film layer and the substrate. The groove depth is 5-15 μm, the width is 20-50 μm, the spacing is 100-200 μm, and the surface roughness Ra = 0.1-0.5 μm. The rough surface forms nano-scale bumps and grooves, which increase the contact area of ​​the film layer and are used to enhance the adhesion of the refractive index matching layer 21. Specifically, laser processing can be used, and the groove morphology is measured by white light interferometry to ensure that there is no melt residue or cracks. In this embodiment, CR-39 resin with a refractive index of 1.50 and an Abbe number of 58 is selected. The diameter is 70 mm, the center thickness is 2.5 mm, and the front surface curvature radius R1 = 100 mm; a CO2 laser with a wavelength of 10.6 μm and a power of 20 W is used to process the V-shaped grooves, and oxygen plasma treatment is used to improve wettability.

[0079] Specific as Figure 2 As shown, a film 20 for vision correction is disposed on the side of a lens substrate 10 away from the eye and includes, from bottom to top, a refractive index matching layer 21, a refractive compensation layer 22, a defocus prevention layer 23, an anti-blue light interference layer 24, and a super-hydrophobic wear-resistant layer 25; the refractive index matching layer 21, the refractive compensation layer 22, the anti-blue light interference layer 24, and the super-hydrophobic wear-resistant layer 25 all cover the entire aperture of the substrate;

[0080] The refractive compensation layer 22 forms an optical zone 26 for refractive correction in the central area, which is about 6 to 8 mm in diameter. The thickness of the refractive compensation layer 22 decreases from the center to the edge.

[0081] The defocus control layer 23 covers the annular area around the optical zone 26, including an annular transition zone 231 and a main defocus zone 232 extending outward from the outer edge of the annular transition zone 231; the defocus control layer 23 is composed of a ZrO2-epoxy resin composite; the inner film thickness of the annular transition zone 231 increases linearly from the inside to the outside, and the radial electric field is used to induce a gradual change in the concentration of ZrO2 nanoparticles to form a radial gradient of refractive index. The concentration of ZrO2 nanoparticles in the main defocus zone 232 is constant, and the peripheral defocus is maintained by a secondary increase in film thickness.

[0082] The annular transition zone 231 originates at the outer edge of the central optical zone 26 and must cover both the natural eye movement range and the retinal hypersensitivity transition zone. The natural eye movement range is defined as a line of sight deviation of ±15°, corresponding to a radial extension of approximately 3-4 mm from the outer edge of the optical zone 26. The retinal hypersensitivity transition zone is a region 2-4 mm beyond the macula, extending 2-4 mm from the outer edge of the optical zone 26 and exhibiting the highest sensitivity to defocus signals. Therefore, the width of the annular transition zone 231 is preferably 3.0-4.5 mm extending from the outer edge of the optical zone 26. The specific range needs to be dynamically adjusted based on the diameter of the optical zone 26.

[0083] The annular transition zone 231 of the defocus prevention and control layer 23 of the present invention induces a concentration gradient distribution of ZrO2 nanoparticles through a radial electric field, so that the defocus amount can change continuously along the radial direction of the lens, forming a defocus gradient field that matches the natural adjustment state of the eyeball, and guiding the eyeball to adapt to the gradient change. When the user's eyeball rotates, the defocus signal is dynamically adjusted along the direction of the visual axis, which not only avoids the visual adaptation fatigue caused by the fixed defocus amount, but also provides differentiated defocus stimulation for retinal areas with different pupil diameters, thereby achieving a balance between prevention and control effect and wearing comfort. The main defocus area 232 is fixedly defocused, corresponding to the blind spot that the eyeball rarely actively looks at. A high-intensity, continuous peripheral defocus signal is provided by fixing the defocus amount. Ensure that the periphery of the retina is always in a defocus state of "inhibiting axial growth" to avoid signal attenuation caused by dynamic changes.

[0084] The refractive index matching layer 21 is a five-layer composite film formed by alternating SiO2 / Al2O3 deposited on the surface of the lens substrate 10. The thickness of the refractive index matching layer 21 ranges from 0.5 to 1.2 μm, with a tangential refractive index gradient Δn ≤ 0.005. Specifically, magnetron sputtering is used with SiO2 (99.99% purity) and Al2O3 (99.95% purity) targets. The five-layer composite film alternates between SiO2 and Al2O3, with the top layer being Al2O3. The thickness of each SiO2 layer is 80 nm, and the thickness of each Al2O3 layer is 60 nm, for a total thickness of 0.7 μm. A tangential refractive index gradient Δn of 0.004 / mm is achieved using a dynamic mask with a slit width gradually varying from 0.5 to 2.0 mm and a tangential translation of the substrate at a step size of 1 mm / step. After deposition, the film is annealed at 180° C. for 1 hour in a nitrogen atmosphere to eliminate stress within the film layer and improve the adhesion of the refractive index matching layer 21 .

[0085] In the present invention, the refractive index gradient of the index-matching layer 21 is orthogonal to the thickness gradient of the refractive compensation layer 22, adapting to different substrate curvatures. The thickness gradient of the refractive compensation layer 22 is arranged along the radial direction of the lens, decreasing from the optical center to the edge to achieve refractive correction. The refractive index gradient is tangential to the lens substrate. A dynamic mask combined with substrate translation is employed. By linearly moving the light-shielding mask, such as by gradually varying the slit width, the deposition ratio of SiO2 / Al2O3 is controlled to gradually vary tangentially. Specifically, during alternating sputtering of SiO2 / Al2O3, the substrate is stepped along the tangential direction, switching targets every 1mm. This achieves a spatial gradient in the SiO2 / Al2O3 film composition ratio, resulting in a refractive index gradient of Δn ≤ 0.005 / mm. The purpose of the refractive index gradient of the refractive index matching layer 21 is that the substrate is a highly curved surface. The orthogonal design of the refractive index gradient can compensate for the change in incident angle caused by the curvature, avoid the refractive index mismatch of the traditional uniform film layer at the edge of the curved surface, and reduce the Fresnel reflectivity.

[0086] Specifically, the refractive compensation layer 22 is fluorine-doped zinc oxide, and the target material is ZnO:AlF3, wherein AlF3 is doped with 2.5at% and has a purity of 99.99%. At a sputtering power of 150W and a working pressure of 2.5×10 -3Sputtering was performed under process conditions of 100 Torr, an Ar / O2 flow ratio of 45 / 5 sccm, and a deposition rate of 1.5 nm / s. By rotating the substrate and shielding with a radial mask, a refractive compensation layer 22 with a center thickness of 15 μm ± 0.2 μm and an edge thickness of 5 μm ± 0.2 μm was produced, wherein the radial gradient thickness change rate was -0.1 μm / mm. The refractive index difference between the top layer of the refractive index matching layer 21 and the refractive index of the refractive compensation layer 22 was ≤ 0.05 to avoid interface reflection loss and excessive film stress. Specifically, the thickness of the refractive compensation layer 22 is the largest at the center, which is 15 μm. Extending outward along its radial direction, the thickness of the refractive compensation layer 22 gradually decreases, and the film structure with a thick center and thin edges is equivalent to the curvature of a concave lens, thereby achieving precise refractive correction. After being covered with the defocus control layer 23, the ZrO2-epoxy resin composite and concentration gradient design of the defocus control layer 23 are utilized to form a dynamically adaptive peripheral defocus area, taking into account both the clarity of the main visual area and the defocus control effect.

[0087] Specific as Figure 3 As shown, the preparation method of the defocus prevention and control layer 23 includes:

[0088] S1: Using the preferred spin coating solution of Examples 1-3, a ZrO2-epoxy resin composite base film layer is formed on the surface of the refractive compensation layer 22 by spin coating, with a thickness of 1.0-1.5 μm;

[0089] S2: applying a radial electric field in the uncured base film layer, and forming a radial ZrO2 concentration gradient decreasing from the inside to the outside and an increasing film thickness through the synergistic effect of electrophoretic migration and centrifugal force;

[0090] like Figure 4 The electrodes are platinum wire ring arrays, and the electrode spacing between adjacent platinum wires is 0.3mm. The electric field lines are more densely distributed and uniform, ensuring that the electrophoretic migration path of ZrO2 nanoparticles in the radial direction is highly controllable. The electric field is aligned with a laser positioning system to ensure that the deviation between the center of the electrode ring and the geometric center of the lens is less than 10μm; the relationship between the centrifugal speed N and the field strength E is determined by the empirical formula E=0.2N+500. A voltage of -1500V is applied to the edge, at which time the electric field strength is 5kV / mm, and then the voltage is gradually reduced along its radial direction until the center is 0V; the surface of the ZrO2 nanoparticles is positively charged, and the high electric field at the edge drives the ZrO2 particles to migrate inward at high speed, forming an initial gradient with high concentration in the center and low concentration at the edge, as shown below. Figure 4 The ZrO2 nanoparticles in the sample induce a direction of 01, the central electric field approaches zero, and the excessive aggregation of particles is suppressed. Centrifuge at 1000-3000 rpm for 15 minutes; the basement membrane layer is not solidified, and the centrifugal acceleration a=ω 2 r drives the resin phase to flow outward, forming a film thickness gradient increasing from 1.0 μm in the center to 1.5 μm at the edge. Figure 4In the resin movement direction 02, the present invention uses the electric field to guide the particle migration and the centrifugal force to regulate the film thickness distribution. The orthogonal effects of the two realize the "decreasing concentration-increasing film thickness" dual gradient.

[0091] S3: An annular transition zone 231 with a width of 3.0 to 4.5 mm is defined, and the edge of the annular transition zone 231 is used as the starting end of the main defocus zone 232. The ZrO2 concentration in the main defocus zone 232 is compensated for by secondary dynamic spraying. During the process, the nozzle moves radially, and the spraying rate increases linearly with the radial position, so that the film thickness of the main defocus zone 232 increases, and the maximum film thickness at the edge of the main defocus zone 232 is ≤25 μm. The present invention sprays a composite liquid containing ZrO2 in the main defocus zone 232 to compensate for the concentration at the outer edge of the annular transition zone 231 and eliminate concentration fluctuations caused by electric field migration.

[0092] In step S3, during dynamic spraying, the ZrO2 mass fraction is consistent with the edge concentration of the annular transition zone, compensating for the concentration fluctuations in the main defocus area 232 that may be caused by electric field migration or centrifugal diffusion, ensuring that the ZrO2 mass fraction in the main area is constant. Figure 3 In the secondary dynamic spraying compensation direction 03, it should be noted here that, in step S2, under electric field migration, the ZrO2 nanoparticles migrate toward the center through the synergistic effect of the radial electric field and the centrifugal force to form a central concentration of 30%~35%, a concentration of 25%~30% at the outer edge of the annular transition zone, and then a gradient distribution decreasing outward; in this step, a ZrO2-epoxy resin compensation liquid with the same concentration as the spin-coating liquid is sprayed from the outer edge of the annular transition zone 231 to the main defocusing area 232 to eliminate the concentration fluctuation caused by the electric field migration and return the ZrO2 concentration in the main defocusing area 232 to 30%±2%.

[0093] Dynamic spraying utilizes a multi-nozzle array moving radially, with adjacent nozzle trajectories overlapping by 50%. Staggered spray paths eliminate film thickness fluctuations, and the nozzle movement speed is 20-40 mm / s. A secondary spray process results in a film thickness distribution in the main defocus area 232 according to a quadratic function Q(r) = 0.06(r-r0)^2 + 1.5 (mL / min). The sensitivity of the human retina to defocus stimuli exhibits a nonlinear spatial distribution: the central macular region has low defocus sensitivity and requires a gentle change; the mid-peripheral region experiences a rapid increase in sensitivity, requiring a sharp increase in defocus; and the far periphery approaches saturation, requiring a slower increase in defocus. If the spray flow rate Q(r) is linear, the film thickness t(r) increases approximately linearly, resulting in a linear plus quadratic superposition of defocus. The resulting defocus distribution fails to conform to the retinal sensitivity curve. In this invention, this quadratic function is an empirical formula optimized through defocus-retinal sensitivity matching experiments. A quadratic function simulates the nonlinear growth of peripheral defocus during natural eye accommodation. Its curvature of 0.06, determined by least squares fitting, matches the spatial distribution of peripheral retinal defocus sensitivity. The spray flow rate Q(r) increases with radial position r, and the film thickness accumulation rate is positively correlated with the required defocus, achieving a linear conversion between film thickness and defocus.

[0094] S4: UV curing excites the photoinitiator to initiate the free radical polymerization of the epoxy resin to form a three-dimensional cross-linked network to fix the ZrO2 gradient distribution. After curing, the film thickness uniformity error is ≤±1.5%.

[0095] In step S4, UV curing is performed in a nitrogen atmosphere. Nitrogen displacement eliminates oxygen inhibition, increasing cure depth and crosslink density. Curing at a temperature of 35-45°C for 5 minutes reduces resin viscosity, promotes leveling of the uncured layer, and minimizes film thickness uniformity. Low-temperature curing also reduces resin shrinkage stress, preventing film cracking or delamination from the refractive compensation layer 22.

[0096] The composite system of ZrO2 nanoparticles and epoxy resin in the defocus control layer 23 of the present invention enhances the inorganic-organic interface bonding force through the dual effects of chemical bonding and physical entanglement, solves the peeling problem caused by the difference in thermal expansion coefficient between the traditional hard oxide film layer and the resin substrate, and significantly improves the durability of the film layer.

[0097] The blue light blocking interference layer 24 comprises a nine-layer structure of alternating TiO2 / SiO2 deposits. The thickness of each TiO2 layer is 20nm, and that of each SiO2 layer is 80nm, for a total thickness of 1.8μm. The layer exhibits an average transmittance of ≥95% in the transmission range, and a blue light cutoff of ≥92% at 455nm. The alternating stacking of 9-15 layers of high-refractive-index TiO2 and low-refractive-index SiO2 creates a broad-spectrum destructive interference in the 400-500nm blue light band. Transmission in other bands, which do not meet the interference conditions, remains ≥95%, ensuring visual clarity. The total thickness is controlled between 1.5 and 2.5μm to avoid stress cracking caused by excessive thickness, ensuring long-term stability and adaptability to lightweight lenses.

[0098] The super-hydrophobic, wear-resistant layer 25 is a diamond-like carbon (DLC) or modified fluorosilane coating, with a water contact angle ≥115° and a pencil hardness ≥9H. Diamond-like carbon (DLC) is suitable for glass and hard resin lenses. The present invention prefers a modified fluorosilane coating, which is an organic monolayer formed by chemical self-assembly or solution deposition. The hardness and wear resistance of the fluorosilane coating can be significantly improved by introducing 10-50 nm SiO2 nanoparticles or Al2O3 nanowhiskers. Specifically, in this embodiment, heptadecafluorodecyltrimethoxysilane is used to introduce 10% SiO2 nanoparticles to enhance the super-hydrophobic, wear-resistant properties of the lens.

[0099] In this invention, a thin film on the front surface of the lens substrate, located away from the eye, achieves vision correction. The anti-fatigue filter 30 on the rear surface, near the eye, comprises a SiO2 / TiO2 / SiO2 / MgF2 coating arranged in this order from the inside out. This, combined with the defocus control layer 23 and the anti-blue light interference layer 24 on the other side, creates a front-to-back functional complementarity, covering all eye needs. In the anti-fatigue filter 30, the inner SiO2 layer has a refractive index close to that of the resin / glass substrate, reducing interfacial reflections. Its low stress alleviates the high-pressure stress of the TiO2 layer, preventing cracking. The TiO2 middle layer, designed with a quarter-wavelength thickness, achieves destructive interference, reflecting harmful blue light from 430-455nm. The low refractive index gradient of the outer SiO2 / MgF2 layer prevents refractive index abrupt changes between layers, reducing the average reflectivity of the final surface. This lens provides medical-grade protection against the harmful blue light from mainstream electronic screens, while also alleviating accommodative fatigue through enhanced red light transmission, making it suitable for over 90% of everyday scenes.

[0100] The resulting lens has a defocus gradient of 0D at the center, +2.50D ± 0.18D in the transition zone, and +4.00D ± 0.20D in the main area. This positive defocus design in the peripheral area slows axial growth and controls myopia progression, while maintaining zero defocus in the central optical zone, ensuring clear imaging of the fovea. Light transmittance is ≥ 98%, and stray light intensity is ≤ 0.6%. This suppresses glare and ghosting caused by internal reflections and surface scattering, enhancing visual comfort. The film retains 97% of its thickness after 500 Taber abrasion cycles, and exhibits no peeling after 1000 hours of damp-heat aging at 85°C / 85% RH.

[0101] Those skilled in the art will appreciate that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A thin film for vision correction, deposited on the surface of a lens substrate, characterized in that: It includes a refractive index matching layer, a refractive compensation layer, a defocus prevention layer, an anti-blue light interference layer and a super hydrophobic wear-resistant layer arranged in sequence from bottom to top; The thickness of the refractive index matching layer is 0.5-1.2 μm, the refractive index gradient Δn is ≤ 0.005, and the difference between the refractive index of the top layer of the refractive index matching layer and the refractive index of the refractive compensation layer is ≤ 0.05; The refractive compensation layer covers the entire aperture and forms an optical zone for refractive correction in the central area, and the film thickness of the refractive compensation layer decreases from the center to the edge; The defocus prevention and control layer covers an annular area around the optical zone, including an annular transition zone and a main defocus area extending outward from the outer edge of the annular transition zone; The defocus prevention and control layer is composed of a ZrO2-epoxy resin composite; the inner film thickness of the annular transition zone increases linearly from the inside to the outside, and the concentration of ZrO2 nanoparticles is induced to gradually decrease from the inside to the outside through a radial electric field, forming a radial gradient of refractive index. The concentration of ZrO2 nanoparticles in the main defocus area is constant, and the peripheral defocus is maintained by a secondary increase in film thickness.

2. The film for vision correction according to claim 1, characterized in that: The refractive index matching layer is a 3-5 layer composite film layer formed by alternately depositing SiO2 / Al2O3 on the surface of the lens substrate.

3. The film for vision correction according to claim 1, characterized in that: The refractive compensation layer is made of fluorine-doped zinc oxide and has a thickness of 5 to 15 μm.

4. The film for vision correction according to claim 1, characterized in that: The preparation method of the defocus prevention and control layer includes: S1: forming a ZrO2-epoxy resin composite base film layer on the surface of the refractive compensation layer by spin coating, with a thickness of 1.0-1.5 μm and a ZrO2 mass fraction of 25-35%; S2: applying a radial electric field in the uncured base film layer to form a radial ZrO2 concentration gradient decreasing from the inside to the outside and an increasing film thickness through the synergistic effect of electrophoretic migration and centrifugal force; S3: Define an annular transition zone with a width of 3.0-4.5 mm, and use the edge of the annular transition zone as the starting point of the main defocus zone. Compensate the ZrO2 concentration in the main defocus zone through secondary dynamic spraying to maintain a constant concentration, and increase the film thickness of the main defocus zone. The maximum film thickness at the edge of the main defocus zone is ≤25 μm. S4: UV curing locks the gradient structure.

5. The film for vision correction according to claim 4, characterized in that: The spin coating solution of the ZrO2-epoxy resin composite comprises, calculated by weight: Epoxy resin: 30-40 parts; ZrO2 nanoparticles: 5-35 parts; Propylene glycol methyl ether acetate: 30-40 parts; Photoinitiator: 1~5 parts; Dispersant: 0.5~1 part; Defoaming agent: 0.1~0.3 parts; The particle size of the ZrO2 nanoparticles is 10-50 nm, and the surface is modified by a silane coupling agent. The epoxy resin is a bisphenol A epoxy resin or an alicyclic epoxy resin.

6. The film for vision correction according to claim 5, characterized in that: In step S2, the outer edge electrode is connected to a negative high voltage power supply, the center electrode is grounded, and the electric field intensity decreases linearly from the outer edge to the center to 0 kV / mm in the radial direction; at the same time, centrifugal force is applied to make the resin phase flow toward the outer edge.

7. The film for vision correction according to claim 5, characterized in that: In step S3, during dynamic spraying, the mass fraction of ZrO2 is consistent with the edge concentration of the annular transition zone. The dynamic spraying adopts a multi-nozzle array moving in radial direction, and the nozzle moving speed is 20-40 mm / s.

8. The film for vision correction according to claim 1, characterized in that: The anti-blue light interference layer is a 9-15 layer structure of alternately deposited TiO2 / SiO2, the thickness of the TiO2 single layer in the anti-blue light interference layer is 10-30 nm, the thickness of the SiO2 single layer is 50-100 nm, the total thickness is 1.5-2.5 μm, the average transmittance in the light transmission band is ≥95%, and the 455 nm blue light cutoff rate is ≥92%; the super hydrophobic wear-resistant layer is a diamond-like carbon or modified fluorosilane coating, the water contact angle is ≥115°, and the pencil hardness is ≥9H.

9. A lens for vision correction, using the film for vision correction according to any one of claims 1 to 8, characterized in that: The lens substrate comprises a lens substrate, wherein the film is arranged on the side of the lens substrate away from the eyes, and an anti-fatigue filter film is also arranged on the side of the lens substrate facing the eyes.

10. The lens for vision correction according to claim 9, characterized in that: The lens substrate is made of resin or glass material, the front surface curvature radius R1 of the lens substrate is 50-200 mm, the back surface curvature radius R2 is 30-150 mm, and the center thickness is 1.0-8.0 mm.

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