A carbon quantum dot-based polyurethane lens and a preparation method thereof

Abstract

The present application relates to the technical field of optical resin lens preparation, in particular to a kind of polyurethane lens based on carbon quantum dots and preparation method thereof.The present application uses 174 high refractive index sulfur-containing polyurethane as base material, constructs high refractive index carbon quantum dots by heavy atom doping, high conjugated fused ring and surface high refractive group grafting, adopts bulk doping composite surface coating process, realizes the small amplitude increase of 0.002~0.01 of lens refractive index on the basis of maintaining lens 1.74 high refractive index, and simultaneously gives full-waveband ultraviolet blocking, precise harmful blue light filtering, high-efficiency antibacterial and high wear resistance, solves the technical problems that traditional polyurethane lens is prone to yellowing, single function, poor wear resistance and antibacterial property, and refractive index is difficult to further improve.The refractive index of the lens prepared by the present application is stable at 1.74-1.75, the visible light transmittance is greater than or equal to 95%, the ultraviolet blocking rate is greater than or equal to 99%, the antibacterial rate is greater than or equal to 99.9%, the pencil hardness is more than 2H, there is no haze and no yellowing, and it is suitable for high-end myopia correction, medical eye protection, children wearing and other scenes, and the process can be mass-produced.

Description

Technical Field

[0001] This invention relates to the field of optical resin lens manufacturing technology, specifically to a polyurethane lens based on carbon quantum dots and its manufacturing method. Background Technology

[0002] Currently, 174 high-refractive-index sulfur-containing polyurethane lenses have become the mainstream material for high-end myopia correction lenses due to their high refractive index of 1.74, thinness, and low optical distortion. However, traditional 174 lenses have drawbacks such as difficulty in further increasing the refractive index, limited functionality, insufficient abrasion resistance, poor antibacterial properties, tendency to yellow with long-term use, and weak UV and blue light protection.

[0003] In existing technologies, traditional UV absorbers are prone to photothermal degradation and yellowing with prolonged wear; inorganic oxide additives tend to aggregate, reducing light transmittance and causing glare; ordinary blue light blocking lenses rely on tinting or reflective coatings, which are prone to color distortion and rainbow patterns, and lack antibacterial and abrasion-resistant synergistic functions. Furthermore, conventional additives have poor compatibility with sulfur-containing polyurethane, which reduces the lens's refractive index, making it impossible to achieve refractive index enhancement.

[0004] In view of the above-mentioned shortcomings, the designer actively researched and innovated in order to create a polyurethane lens based on carbon quantum dots and its preparation method, so as to make it more industrially valuable. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide a polyurethane lens based on carbon quantum dots and its preparation method.

[0006] The present invention discloses a polyurethane lens based on carbon quantum dots, using 174 high-refractive-index sulfur-containing polyurethane as a substrate, incorporating high-refractive-index carbon quantum dots in the substrate, and coating the lens surface with a carbon quantum dot-modified hardening coating; the high-refractive-index carbon quantum dots are prepared by heavy atom doping, construction of a highly conjugated polycyclic aromatic hydrocarbon structure, and grafting of high-refractive-index groups on the surface, with a refractive index of 1.70-1.85, a particle size of 2-6 nm, and the surface containing hydroxyl groups, epoxy groups, and sulfur / benzene ring high-refractive-index segments.

[0007] The high-refractive-index carbon quantum dots match the 174 refractive index, without damaging the optical structure of the substrate; the nanoscale particle size is <10nm, which does not produce light scattering and ensures high light transmittance; the surface functional groups form covalent bonds with polyurethane, resulting in stable dispersion and no agglomeration. While maintaining a high refractive index of 1.74, it achieves multifunctional integration of UV resistance, precise blue light protection, antibacterial properties, wear resistance, and yellowing resistance, with no haze, no yellowing, and excellent optical performance.

[0008] Furthermore, the heavy atom doping of the high refractive index carbon quantum dots is one or more combinations of S, P, Cl, and Br; the fused ring aromatic structure is a highly conjugated sp² carbon core; and the surface is grafted with one or more of sulfur-containing chains, benzene ring chains, and brominated aromatic chains.

[0009] The intrinsic refractive index of carbon quantum dots is significantly improved by increasing electronic polarizability through heavy atom doping; the higher the conjugation of the sp² carbon core, the stronger the light dispersion and the higher the refractive index; and the high-fold segment grafting is highly compatible with the chemical structure of 174 sulfur-containing polyurethane, reducing interface defects and improving compatibility.

[0010] Furthermore, the mass fraction of the high-refractive-index carbon quantum dot pure powder in the bulk is 0.01% to 0.05%; the effective solid content of carbon quantum dots in the surface coating is 0.01% to 0.08%.

[0011] The 174 sulfur-containing system is extremely sensitive to color development; a small amount can achieve the desired function without affecting the refractive index. If the concentration is too low, the function will be insufficient, and if the concentration is too high, it will easily cause yellowing and increased haze. The addition range of this invention is the optimal window for balancing function and optics.

[0012] A method for preparing a polyurethane lens based on carbon quantum dots includes the following steps:

[0013] (1) Custom preparation of high refractive index carbon quantum dots: Using carbon source as matrix, high refractive index carbon quantum dots with a refractive index of 1.70 to 1.85 are prepared by doping with heavy atoms, constructing highly conjugated sp² carbon cores of polycyclic aromatic hydrocarbons, and grafting high-folded segments containing sulfur / benzene rings / bromoaromatic hydrocarbons onto the surface. The quantum dots are then prepared into anhydrous ethanol or propylene glycol methyl ether dispersions with a solid content of 1% to 5% and a yellowness index of b. ≤1.0; (2) 174 bulk doping: The high-refractive carbon quantum dot ethanol solution was premixed with anhydrous ethanol and ultrasonically dispersed. Then, 174 thiol A component was added and ultrasonically dispersed. Then, 174 isocyanate B component was added and stirred. After vacuum degassing, the mixture was injected into a mold and cured by step heating to obtain the substrate. (3) Preparation of carbon quantum dot modified hardening coating: High-refractive-index organosilane hardening liquid, high-refractive-index carbon quantum dot dispersion, coupling agent, catalyst and mixed solvent are prepared into coating liquid, and after dip coating, leveling, pre-baking and curing, composite coated lens is obtained; (4) Post-processing and inspection: The lens is cleaned, coated with AR anti-reflective film, and shipped after passing the inspection.

[0014] Furthermore, in step (2), by weight, there are 490-500 parts of 174 thiol A component, 490-500 parts of 174 isocyanate B component, 0.15-2.5 parts of 2% high-carbon quantum dot ethanol solution, and 0.15-2.5 parts of anhydrous ethanol; the ultrasonic dispersion frequency is 35-40 kHz, the temperature is 20-30 °C, the time is 20-30 min, the stirring speed is 300 rpm, the stirring time is 20 min, the vacuum degassing pressure is 0.095 MPa, and the time is 10-15 min.

[0015] This invention first prepares specialized high-refractive-index carbon quantum dots to ensure controllable structure and performance; bulk doping achieves internal functionalization, and coating achieves surface strengthening; stepwise processes avoid carbon quantum dot agglomeration and incomplete resin curing. Agglomerates are broken up by ultrasonication to achieve uniform nanoscale dispersion; low-speed, gentle stirring avoids introducing air bubbles and prevents damage to the carbon quantum dot structure; high vacuum thoroughly degasses the particles, preventing pinholes, air lines, and fogging in the lenses.

[0016] Furthermore, the step curing curve in step (2) is as follows: 45℃ for 2.0h, 55℃ for 2.0h, 65℃ for 3.0h, 75℃ for 2.0h, 85℃ for 1.0h, with natural cooling time ≥2h, and curing temperature not higher than 90℃ to avoid yellowing of the lens.

[0017] By gradually increasing the temperature, the thiol and isocyanate crosslink slowly, resulting in low internal stress and no cracking; a temperature of ≤90℃ can avoid high-temperature oxidation and yellowing of the 174 sulfur system; slow cooling eliminates thermal stress and ensures the accuracy of the lens surface shape.

[0018] Furthermore, in step (3), the coating liquid, by weight, comprises 940–950 parts of high-refractive-index organosilane hardening liquid, 14–16 parts of 2% (w / w) high-refractive-index carbon quantum dot ethanol solution, 9–11 parts of KH560 coupling agent, 1–3 parts of dibutyltin dilaurate catalyst, and 26–30 parts of anhydrous ethanol / isopropanol mixed solvent. KH560 provides epoxy groups to connect carbon quantum dots and silane hardening layer, forming a covalent bond network; the catalyst cures gently, avoiding film stress caused by rapid crosslinking; the mixed solvent ensures leveling properties, without rainbow patterns or orange peel.

[0019] Furthermore, the dipping parameters in step (3) are as follows: after plasma cleaning for 60s, the material is immersed in the coating liquid, and the lifting speed is controlled at 1.5 to 2.0 mm / s; the leveling time is 5 min; the pre-baking temperature and time are 60℃ and 10 min; the curing temperature and time are 105℃ and 75 min; and the film thickness is 3.0 to 3.5 μm.

[0020] Slow lifting ensures uniform film thickness and no flow marks; leveling balances surface tension and eliminates defects; pre-baking removes solvents before high-temperature curing to avoid blistering and pinholes; 3.0–3.5 μm is the optimal film thickness for wear resistance and optical properties, too thick a film is prone to cracking, and too thin a film is not wear-resistant enough.

[0021] Furthermore, the use of aqueous carbon quantum dots is strictly prohibited throughout the entire process, and the coating solution must be prepared and used immediately. Water reacts with the 174 isocyanate groups, leading to incomplete curing, whitening, and a sharp increase in haze; long-term coexistence of carbon quantum dots and catalysts can cause side reactions, reducing functionality and stability.

[0022] The polyurethane lenses described can be used in high-end myopia lenses, medical protective lenses, children's optical lenses, and driving protection lenses.

[0023] By means of the above-described solution, the present invention has at least the following advantages: (1) This invention customizes high-refractive-index carbon quantum dots by heavy atom doping, high conjugated fused ring construction, and grafting high-refractive-index groups onto the surface, and adopts bulk doping and surface coating composite process to achieve synergistic improvement in five dimensions of 174 high-refractive-index sulfur-containing polyurethane lenses: optical performance, eye protection function, mechanical durability, hygiene and safety, and long-term stability. (2) This invention uses high-refractive-index carbon quantum dots with a refractive index of 1.70 to 1.85. Even a small amount of doping can increase the refractive index of the 174 lens by 0.002 to 0.01, stabilizing it at 1.74 to 1.75, resulting in a thinner, lighter lens with less optical distortion. The introduction of heavy atoms increases the electronic polarizability of the material, directly improving the intrinsic refractive index of the carbon quantum dots. The construction of polycyclic aromatic hydrocarbons and large conjugated sp² carbon cores expands the conjugated system, enhances light dispersion, and further increases the refractive index. Surface grafting of sulfur-containing chains, benzene rings, and brominated aromatic hydrocarbon chains highly matches the chemical structure of the 174 sulfur-containing polyurethane, resulting in a continuous transition of the interface refractive index without refractive index collapse. This overcomes the bottleneck of traditional additives failing to increase the refractive index of high-refractive-index lenses, achieving a thinner upgrade of high-refractive-index lenses without sacrificing light transmittance or producing haze.

[0024] (3) Carbon quantum dots have a conjugated π-electron system, which generates strong π–π in the ultraviolet region of 200–400 nm. With n–π Transition absorption allows for the capture of ultraviolet photons across the entire wavelength range, converting light energy into harmless heat or low-energy red light dissipation without photodegradation. Compared to traditional organic ultraviolet absorbers, carbon quantum dots, being carbon-based nanostructures, possess extremely strong chemical inertness, exhibiting no decomposition or performance degradation under long-term light exposure. This fundamentally inhibits chain breakage, oxidative yellowing, and embrittlement of the substrate caused by ultraviolet irradiation. The resulting lenses achieve a UVA / UVB blocking rate of 90-100%, with a transmittance decrease of less than 2% after 200 hours of ultraviolet aging and no significant yellowing.

[0025] (4) The band structure and size effect of carbon quantum dots can precisely control the position of the absorption peak, producing characteristic absorption only in the 415-455nm band, without interfering with the visible light color gamut. The resulting lens can precisely absorb high-energy harmful blue light in the 415-455nm range, while retaining beneficial blue light in the 455-500nm range, with a visible light transmittance of 95-99%, no color shift, no yellowing, and no rainbow pattern.

[0026] (5) The carbon quantum dots of this invention have a particle size of 2-6 nm, which is much smaller than the wavelength of visible light and does not produce Rayleigh scattering; the high refractive index of the carbon quantum dots is highly matched with the 174 refractive index, which greatly reduces interface reflection and significantly reduces stray light and ghosting; the anhydrous system is dispersed and precisely controlled in quantity, with no agglomeration, no whitening, and no optical defects. The visible light transmittance is ≥95%, the haze is <0.30%, and there is no ghosting, no glare, and no scattering white spots.

[0027] (6) The hydroxyl and epoxy groups on the surface of carbon quantum dots form covalent cross-links with polyurethane and siloxane hardening layers, constructing a dense and rigid network; the nano-carbon core plays a physical reinforcing role, inhibiting the spread of surface scratches; the coating forms a Si–O–C high-hardness three-dimensional network, which, combined with the rigid structure of carbon quantum dots, achieves ultra-wear resistance. No additional multi-layer hardening is required; a single coating can achieve high wear resistance, simplifying the process and improving durability. The hardness of the final lens pencil is increased from F to over 2H. It shows no obvious scratches after 500g of steel wool pressure for 500 cycles, and it does not bubble or peel off after boiling in water for 1 hour.

[0028] (7) The active sites and oxygen-containing functional groups on the surface of carbon quantum dots can contact and destroy the envelope structure of bacteria and viruses, inhibiting respiration and replication, thus achieving physical antibacterial effects without drug leaching or the development of drug resistance. Carbon quantum dots are all-carbon-based inorganic / inorganic structures, resistant to light and heat, non-oxidizing, and non-decomposing; the anhydrous process and low-temperature step-curing avoid high-temperature yellowing of the 174 sulfur-containing system; carbon quantum dots preferentially absorb ultraviolet light, protecting the substrate from photo-oxidation. The resulting lenses have extremely strong antibacterial and light and heat resistance, do not yellow with long-term use, and their performance does not degrade.

[0029] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below. Detailed Implementation

[0030] The specific embodiments of the present invention will be described in further detail below with reference to the examples. These examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0031] (1) Custom preparation of high refractive index carbon quantum dots: Using a carbon source as a matrix, high-refractive-index carbon quantum dots with refractive indices of 1.70–1.85 and up to 1.90 were prepared by doping with S, P, Cl, and Br heavy atoms, constructing highly conjugated sp² carbon cores of fused-ring aromatics, and grafting high-refractive-index segments containing sulfur / benzene rings / bromoaromatics onto the surface. These were then formulated into anhydrous ethanol or propylene glycol methyl ether dispersions with a solid content of 1%–5% and a yellowness index of b. ≤1.0; (2) 174 (1.74 high refractive index sulfur-containing polyurethane) bulk doping: Weigh out 490-500 parts of component 174 A (thiol), 490-500 parts of component 174 B (isocyanate), 0.15-2.5 parts of 2% high-carbon quantum dot ethanol solution, and 0.15-2.5 parts of anhydrous ethanol by weight. The high-refractive-index carbon quantum dot ethanol melt was premixed and ultrasonically dispersed with 174 mercaptan A agent, then isocyanate B agent was added and stirred. After vacuum degassing, it was injected into a mold and cured by step heating to obtain the substrate. The ultrasonic dispersion frequency was 35–40 kHz, the temperature was 20–30 °C, the time was 20–30 min, the stirring speed was 300 rpm, the stirring time was 20 min, and the vacuum degassing pressure was 0.095 MPa for 10–15 min.

[0032] The step curing curve is as follows: 45℃ for 2.0h, 55℃ for 2.0h, 65℃ for 3.0h, 75℃ for 2.0h, 85℃ for 1.0h, with a natural cooling time of ≥2h and a curing temperature not exceeding 90℃ to avoid yellowing of the lenses.

[0033] (3) Preparation of carbon quantum dot modified hardening coating: Weigh out 940-950 parts by weight of high-refractive-index organosilane hardening solution, 14-16 parts by weight of 2% high-refractive-index carbon quantum dot ethanol solution, 9-11 parts by weight of KH560 coupling agent, 1-3 parts by weight of dibutyltin dilaurate catalyst, and 26-30 parts by weight of anhydrous ethanol / isopropanol mixed solvent.

[0034] The high-refractive-index organosilane hardening fluid is CrystalCoat® CC-1670.

[0035] A coating solution is prepared by mixing high-refractive-index organosilane hardening liquid, high-refractive-index carbon quantum dot dispersion, coupling agent, catalyst and mixed solvent. After dip coating, leveling, pre-baking and curing, a composite coated lens is obtained. The dip-coating parameters are as follows: after plasma cleaning for 60 seconds, immerse in the coating solution, control the lifting speed at 1.5 to 2.0 mm / s; leveling time is 5 min; pre-baking temperature and time are 60℃ and 10 min; curing temperature and time are 105℃ and 75 min; and film thickness is 3.0 to 3.5 μm.

[0036] (4) Post-processing and inspection: Lenses are cleaned, coated with AR anti-reflective coating, and shipped after passing inspection.

[0037] Example Example 1: S-doped high-refractive carbon quantum dot 174 lens (1) Preparation of S-doped high-refractive-index carbon quantum dots: 1. Weigh 20g of citric acid and 4g of thiourea, dissolve them in 200mL of anhydrous ethanol, and stir for 30min; 2. Transfer to a hydrothermal reactor and react at 200℃ for 8 hours. Cool to room temperature to obtain the reaction solution. 3. Filter the above reaction solution through a 0.22 μm filter membrane, dialyze through a dialysis bag for 24 h, and concentrate by rotary evaporation to obtain a concentrated solution; 4. After replacing the solvent with anhydrous ethanol, the solution is reconstituted with the concentrate to obtain a dispersion with a solid content of 2%; 5. Add a sulfur-containing silane coupling agent to the above dispersion, reflux at 70°C for 3 hours to complete surface grafting, and finally obtain S-doped high-refractive-index carbon quantum dots: particle size 2-4 nm, refractive index 1.78, yellowness index b =0.8.

[0038] (2) Fabrication of bulk doped substrate: 1. 499.85g of component 174A, 499.85g of component 174B, 0.75g of ethanol solution containing 2% S-doped high-refractive carbon quantum dots, and 0.75g of anhydrous ethanol were premixed and ultrasonically treated with the following parameters: 40kHz, 25℃, and 5min. 2. The above premixed solution was subjected to vacuum degassing with the following parameters: 0.095 MPa for 12 min. 3. Pour into the mold and cure according to the stepped curing curve. The stepped curing curve is as follows: 45℃ for 2.0h, 55℃ for 2.0h, 65℃ for 3.0h, 75℃ for 2.0h, 85℃ for 1.0h, and the natural cooling time is 2h.

[0039] 4. Open the mold and clean it to obtain the substrate.

[0040] (3) Preparation of modified hardening coating 1. Coating solution formulation: 945g of high-refractive-index silane hardening solution, 15g of 2% S-doped high-refractive-index carbon quantum dot ethanol solution, 10g of silane coupling agent KH560, 2g of dibutyltin dilaurate, and 28g of a mixture of ethanol and isopropanol in equal mass ratio. 2. Solution preparation: First, ultrasonically mix the equal mass ratio of ethanol and isopropanol with 2% S-doped high-refractive-index carbon quantum dot ethanol solution for 10 min. Then add the coupling agent and stir for 15 min. Add the hardening solution and stir for 20 min. Finally, add the catalyst and stir for 10 min. Let stand for 30 min to remove bubbles and then filter. 3. Pretreatment: Plasma cleaning for 60 seconds; 4. Dip coating: Immerse the substrate in the coating solution, control the lifting speed at 1.8 mm / s, and level for 5 minutes to complete the dip coating; 5. Pre-bake and cure the dip-coated substrate. The pre-bake temperature and time are 60℃ and 10min; the curing temperature and time are 105℃ and 75min. 6. Finally, a lens film thickness of 3.0–3.5 μm was obtained. After depositing an AR antireflection coating, an S-doped high-refractive-index carbon quantum dot 174 lens was obtained.

[0041] (4) Performance testing Refractive index: 1.745 (increased by 0.005); Haze: 0.22%; b 1.5; Visible light transmittance: 96.5%; UV blocking: 99.5%; Antibacterial rate: 99.95%; Pencil hardness: 3.5H; Adhesion: 5B.

[0042] This embodiment employs sulfur-doped, polycyclic aromatic hydrocarbon (PAH) structured, sulfur-grafted high-refractive-index carbon quantum dots. The sulfur atoms enhance electronic polarizability, and the large conjugated sp² carbon nuclei strengthen light dispersion, resulting in a refractive index of 1.78 for the carbon quantum dots, higher than that of the 174 substrate. Therefore, even a small amount of doping can slightly increase the lens refractive index by 0.005. The carbon quantum dots exhibit strong π–π and n–π absorption in the 200–400 nm ultraviolet region, achieving full-band ultraviolet blocking. Through size effects and bandgap modulation, they precisely absorb harmful blue light in the 415–455 nm range without color shift. The nanoparticle size of 2–4 nm is much smaller than the visible light wavelength, resulting in no Rayleigh scattering. Combined with an anhydrous dispersion system, this leads to a haze of less than 0.3% and a transmittance of over 95%. The hydroxyl and epoxy groups on the carbon quantum dot surface form covalent cross-links with polyurethane and the hardening layer, constructing a Si–O–C rigid network, increasing the hardness to 3.5H. Surface active sites disrupt bacterial membranes, achieving 99.95% high-efficiency antibacterial activity. The above results verify that the present invention can simultaneously achieve the comprehensive technical effects of slightly increased refractive index, high light transmittance, full UV protection, precise blue light resistance, high wear resistance, high efficiency antibacterial effect, and low yellowing.

[0043] Example 2: Br-doped high-refractive-index carbon quantum dot 174 lens 1. Weigh 18g of glucose and 3g of sodium bromide, dissolve them in 200mL of anhydrous ethanol, and stir for 30min; 2. Transfer to a hydrothermal reactor and react at 210℃ for 7 hours. Cool to room temperature to obtain the reaction solution. 3. Filter the above reaction solution through a 0.22 μm filter membrane, dialyze through a dialysis bag for 24 h, and concentrate by rotary evaporation to obtain a concentrated solution; 4. After replacing the solvent with propylene glycol methyl ether, the solution is reconstituted with the concentrate to obtain a dispersion with a solid content of 2%; 5. Add a bromoaromatic coupling agent to the above dispersion, reflux at 75°C for 3 hours to complete surface grafting, and finally obtain Br-doped high-refractive-index carbon quantum dots: particle size 3-5 nm, refractive index 1.82, yellowness index b =0.9.

[0044] (2) Preparation of bulk doped substrate 1. Formula: 499.85g of 174 component A, 499.85g of 174 component B, 1.5g of Br-doped high-refractive-index carbon quantum dot propylene glycol methyl ether solution (2% by mass), and 1.5g of propylene glycol methyl ether; 2. The dispersion, stirring, degassing, and curing processes are the same as in Example 1.

[0045] (3) Coating preparation The process is the same as in Example 1.

[0046] (4) Performance testing Refractive index: 1.748 (increased by 0.008); Haze: 0.24%; b 1.6; Visible light transmittance: 96.3%; UV blocking: 99.4%; Antibacterial rate: 99.93%; Pencil hardness: 3.5H; Adhesion: 5B.

[0047] This embodiment utilizes high-refractive-index carbon quantum dots doped with Br heavy atoms, featuring highly conjugated sp² carbon cores and brominated aromatic linkages. Br atoms significantly enhance electronic polarizability, expanding the conjugated system and further increasing the refractive index to 1.82, higher than the 174 substrate, resulting in a 0.008 increase in lens refractive index and achieving a thinner and lighter high-refractive-index lens effect. The conjugated structure of the carbon quantum dots can capture ultraviolet light across the entire wavelength range, converting light energy into heat energy for dissipation and preventing photo-oxidation and yellowing of the substrate. The band structure precisely matches the 415–455nm harmful blue light absorption peak, achieving eye protection without color distortion. A particle size of 3–5nm ensures no scattering and low haze; anhydrous processing and precise addition avoid agglomeration and whitening, maintaining high light transmittance. The carbon quantum dots and silane hardening layer form a dense cross-linked structure, significantly improving wear resistance; surface active sites achieve physical antibacterial properties, with an antibacterial rate of 99.93%. Results verification: This invention, through the tunability and controllability of heavy atom type, conjugated structure and graft chain, can stably achieve the technical goals of improved refractive index, superior optics, functional integration and long-term stability.

[0048] Comparison Example Comparison Example 1: Pure 174 lens (no carbon quantum dots) 1. Use pure 174 A / B components and cure using conventional processes; 2. The surface is coated with ordinary hardening liquid and then coated with an AR film; 3. Performance: Refractive index 1.740; no UV or blue light protection; no antibacterial properties; pencil hardness H; prone to yellowing with long-term use.

[0049] This comparative example did not include any functional particles; the substrate only possessed basic optical properties, lacking UV absorption, blue light filtering, and antibacterial capabilities. The 174 resin itself has low hardness, lacks a reinforcing mechanism, and is easily scratched; it also lacks UV-absorbing components, making it prone to oxidative degradation and chain breakage under long-term light exposure, leading to yellowing and embrittlement. This demonstrates that only by introducing high-refractive-index carbon quantum dots can UV blocking, blue light blocking, antibacterial properties, abrasion resistance, yellowing resistance, and refractive index enhancement be achieved. A blank substrate cannot meet the multifunctional requirements of high-end lenses.

[0050] Comparison Example 2: Ordinary carbon quantum dot 174 lens 1. Ordinary carbon quantum dots (refractive index 1.55) are used, with an addition amount of 0.015%; 2. The process is the same as in Example 1; 3. Performance: Refractive index 1.739 (slightly decreased); Haze 0.26%; No refractive index enhancement effect.

[0051] Ordinary carbon quantum dots are composed of C, O, N, and H, with a refractive index of only 1.45–1.65, significantly lower than the 1.74 of 174. Therefore, their addition will slightly lower the refractive index of the lens. Ordinary carbon quantum dots have not undergone heavy atom doping, high conjugated structure, or grafting of high-refractive-index groups, and therefore lack the ability to increase the refractive index. Furthermore, they have poor compatibility with sulfur-containing polyurethane, easily causing a slight increase in haze. This proves that only the high-refractive-index carbon quantum dots of this invention can maintain or increase the refractive index of the lens while achieving functionalization; ordinary carbon quantum dots do not possess this effect.

[0052] Comparative Example 3: Traditional organic UV absorber 174 lens 1. Use agent 174A / B, add 0.3wt% of traditional benzophenone-based organic UV absorber, and mix by conventional stirring; 2. Prepare substrates according to the same curing curve; 3. The surface is coated with ordinary hardening liquid and then coated with AR film.

[0053] 4. Verification of technical effectiveness Refractive index: 1.740 (no improvement); UV blocking: initial 85%, drops to 55% after 200 hours of UV aging, showing significant attenuation; Blue light protection: no harmful blue light filtering function; Visible light transmittance: 90%, noticeable yellowing with long-term use, with a continuous decrease in transmittance; Haze: 0.45%; Yellowness index b 3.2; Mechanical properties: Pencil hardness H, no improvement, easily scratched; Antibacterial properties: None; Stability: Easily degraded by light and heat, performance significantly degraded after six months.

[0054] Traditional organic UV absorbers are small-molecule organic compounds that are prone to photodegradation, breakage, and volatilization under light and heat conditions, leading to a rapid decline in their UV protection capabilities. Their molecular structure lacks selective absorption of blue light, rendering them ineffective for eye protection. Organic molecules do not participate in resin cross-linking, thus failing to improve hardness and wear resistance; they lack antibacterial structures and therefore do not possess hygienic functions; long-term use easily leads to oxidation and yellowing, causing color differences and decreased light transmittance. This demonstrates that the carbon quantum dots of this invention possess a stable carbon-based structure that does not degrade, decay, or yellow, exhibiting significantly superior functionality and stability compared to traditional organic UV absorbers.

[0055] Comparison Example 4: Traditional Inorganic Oxide (TiO2) 174 Lens 1.0 wt% nano-TiO2 was added to the 1.174 substrate and dispersed by high-speed stirring; 2. Curing, hardening, and AR film coating are performed using the same process.

[0056] 3. Verification of technical effectiveness Refractive index: 1.738 (slightly decreased); UV blocking: 90%, but TiO2 tends to agglomerate; Blue light protection: non-selective blocking, poor effect; Visible light transmittance: 87%, severe scattering, low transmittance; Haze: 1.2%, white spots appear, high haze; Yellowness index b 2.8; Mechanical properties: moderate hardness, easily brittle; Antibacterial properties: weak, antibacterial rate <60%; Appearance: prone to glare and ghosting, poor visual quality.

[0057] Nano-TiO2 particles have a large size and high surface energy, making them prone to agglomeration in resin, forming micron-sized scattering particles. This leads to a sharp increase in haze, decreased light transmittance, and increased stray light and ghosting. The poor refractive index matching between TiO2 and 174 further reduces the overall refractive index. The weak bonding between inorganic particles and resin easily causes stress concentration and cracking. Furthermore, the lack of selective blue light filtering results in weak antibacterial effects. This demonstrates that the high-refractive-index carbon quantum dots of this invention exhibit uniform nano-dispersion, no agglomeration, low haze, high light transmittance, and refractive index matching, resulting in overall optical and performance performance far superior to inorganic oxide systems.

[0058] Comparison Example 5: Ordinary blue light blocking resin 174 lens 1. Uses ordinary blue light blocking substrate, with a reflective film layer for blue light blocking; 2. Conventional curing, hardening, and coating with anti-blue light AR film.

[0059] Technical effect verification Refractive index: 1.740; UV blocking: weak, only 70%; Blue light protection: full-band blocking, prone to yellowing and color distortion; Visible light transmittance: 88%–91%, film reflection reduces light transmission; Haze: 0.55%; Yellowness index b 3.5; Mechanical properties: Pencil hardness H, requires additional hardening; Antibacterial properties: None; Appearance: Prone to rainbow patterns, stray light, and obvious ghosting.

[0060] Ordinary blue light blocking relies on dyed or reflective coatings, which non-selectively absorb blue light, leading to color cast, yellowing, and reduced transmittance. These coatings are also prone to rainbow-like patterns, stray light, and ghosting, degrading visual quality. They lack full UV blocking, antibacterial mechanisms, and covalent reinforcement structures, resulting in low hardness, easy scratching, and yellowing. This invention, however, verifies that it achieves a beneficial blue light blocking effect through precise bandgap control of carbon quantum dots, with no color cast or yellowing. It also integrates UV protection, antibacterial properties, scratch resistance, yellowing resistance, and refractive index stability / enhancement, offering superior functionality and user experience compared to ordinary blue light blocking lenses.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A polyurethane lens based on carbon quantum dots, characterized in that, Using 174 high-refractive-index sulfur-containing polyurethane as the substrate, high-refractive-index carbon quantum dots are bulk-doped inside the substrate, and a carbon quantum dot-modified hardening coating is coated on the lens surface. The high-refractive-index carbon quantum dots are prepared by heavy atom doping, construction of a highly conjugated polycyclic aromatic hydrocarbon structure, and grafting of high-refractive-index groups on the surface. The refractive index is 1.70-1.85, the particle size is 2-6 nm, and the surface contains hydroxyl groups, epoxy groups, and sulfur / benzene ring high-refractive-index segments.

2. The polyurethane lens based on carbon quantum dots according to claim 1, characterized in that, The high-refractive-index carbon quantum dots are doped with one or more of S, P, Cl, and Br; the polycyclic aromatic hydrocarbon structure is a highly conjugated sp² carbon core; and the surface is grafted with one or more of sulfur-containing chains, benzene ring chains, and bromoaromatic chains.

3. The polyurethane lens based on carbon quantum dots according to claim 1, characterized in that, The mass fraction of the high-refractive-index carbon quantum dot pure powder in the bulk is 0.01% to 0.05%; the effective solid content of carbon quantum dots in the surface coating is 0.01% to 0.08%.

4. A method for preparing a polyurethane lens based on carbon quantum dots, characterized in that, Includes the following steps: (1) Custom preparation of high refractive index carbon quantum dots: Using carbon source as matrix, high refractive index carbon quantum dots with a refractive index of 1.70 to 1.85 are prepared by doping with heavy atoms, constructing highly conjugated sp² carbon cores of polycyclic aromatic hydrocarbons, and grafting high-folded segments containing sulfur / benzene rings / bromoaromatic hydrocarbons onto the surface. The quantum dots are then prepared into anhydrous ethanol or propylene glycol methyl ether dispersions with a solid content of 1% to 5% and a yellowness index of b. ≤1.0; (2) 174 bulk doping: The high-refractive carbon quantum dot ethanol solution was premixed with anhydrous ethanol and ultrasonically dispersed. Then, 174 thiol A component was added and ultrasonically dispersed. Then, 174 isocyanate B component was added and stirred. After vacuum degassing, the mixture was injected into a mold and cured by step heating to obtain the substrate. (3) Preparation of carbon quantum dot modified hardening coating: High-refractive-index organosilane hardening liquid, high-refractive-index carbon quantum dot dispersion, coupling agent, catalyst and mixed solvent are prepared into coating liquid, and after dip coating, leveling, pre-baking and curing, composite coated lens is obtained; (4) Post-processing and inspection: The lens is cleaned, coated with AR anti-reflective film, and shipped after passing the inspection.

5. The preparation method according to claim 4, characterized in that, In step (2), by weight, there are 490-500 parts of 174 thiol A component, 490-500 parts of 174 isocyanate B component, 0.15-2.5 parts of 2% high-carbon quantum dot ethanol solution, and 0.15-2.5 parts of anhydrous ethanol; the ultrasonic dispersion frequency is 35-40kHz, the temperature is 20-30℃, the time is 20-30min, the stirring speed is 300rpm, the stirring time is 20min, the vacuum degassing pressure is 0.095MPa, and the time is 10-15min.

6. The preparation method according to claim 4, characterized in that, The step curing curve in step (2) is as follows: 45℃ for 2.0h, 55℃ for 2.0h, 65℃ for 3.0h, 75℃ for 2.0h, 85℃ for 1.0h, natural cooling time ≥2h, curing temperature not higher than 90℃, to avoid yellowing of the lens.

7. The preparation method according to claim 4, characterized in that, In step (3), the coating liquid, by weight, includes 940-950 parts of high-refractive-index organosilane hardening liquid, 14-16 parts of 2% high-refractive-index carbon quantum dot ethanol solution, 9-11 parts of KH560 coupling agent, 1-3 parts of dibutyltin dilaurate catalyst, and 26-30 parts of anhydrous ethanol / isopropanol mixed solvent.

8. The preparation method according to claim 4, characterized in that, The parameters for dip coating in step (3) are as follows: after plasma cleaning for 60 seconds, the coating liquid is immersed and the lifting speed is controlled at 1.5 to 2.0 mm / s; the leveling time is 5 min; the pre-baking temperature and time are 60℃ and 10 min; the curing temperature and time are 105℃ and 75 min; and the film thickness is 3.0 to 3.5 μm.

9. The preparation method according to claim 4, characterized in that, The use of aqueous carbon quantum dots is strictly prohibited throughout the entire process, and the coating solution must be prepared and used immediately.

10. The polyurethane lens according to claim 1, characterized in that, It can be applied to high-end myopia lenses, medical protective lenses, children's optical lenses, and driving protective lenses.