A frame type up-conversion infrared visualization glasses and its preparation method and application

Abstract

This invention provides a frame-type upconversion infrared visualization glasses, its fabrication method, and its applications, relating to the fields of infrared visualization materials and wearable optical devices. The optical lens of the glasses comprises, from the incident side to the wearer side, an infrared anti-reflection layer, an upconversion core-shell luminescent layer, a visible light gain layer, an infrared reflective layer, and a protective eye layer. This invention uses mesoporous SiO2 nanospheres as the core to construct the upconversion core-shell luminescent layer, and combines it with the infrared anti-reflection layer, visible light gain layer, infrared reflective layer, and protective eye layer to form a five-layer optical enhancement structure. This structure is integrated into the frame lens using a layer-by-layer injection molding and graded curing process, achieving multiple recycling of near-infrared light, efficient loading of rare-earth luminescent components, a significant improvement in upconversion luminescence efficiency, and a synergistic enhancement of visible light output brightness and uniformity on the wearer side. It has broad application prospects in the field of visual assistance for patients with retinitis pigmentosa and late-stage glaucoma.

Description

Technical Field

[0001] This invention relates to the field of infrared visualization materials and wearable optical devices, and in particular to a frame-type upconversion infrared visualization glasses, its preparation method, and its application. Background Technology

[0002] Retinitis Pigmentosa (RP) and glaucoma are two blinding eye diseases characterized primarily by irreversible visual impairment. In the middle and late stages of RP, the continuous degeneration of rod cells and some cone cells leads to a significant decrease in visible light sensitivity, manifesting as impaired dark adaptation, night blindness, and low-light visual loss. In the late stages of glaucoma, irreversible damage to the optic nerve fibers often results in "tunnel vision," with further shrinkage of the effective visual field in low-visibility scenarios such as nighttime, dim light, and smoke. The resulting visual impairment in low-light conditions severely impacts daily navigation and significantly increases the risks of falls, traffic accidents, and other safety hazards. Therefore, there is an urgent need for a long-term wearable, non-surgical assistive device that can effectively enhance visual perception in low-light environments.

[0003] Infrared light is a low-energy radiation that is ubiquitous in nature. It has the advantages of strong penetration and low background interference in nighttime and smoky environments, but it cannot be directly perceived by the human eye. Converting near-infrared light into visible light and presenting it to patients with visual impairment through wearable devices has become a cutting-edge research area in recent years. However, existing high-sensitivity infrared detection solutions, such as photomultiplier tubes, InGaAs detectors, and microbolometer arrays, are complex in structure, bulky, power-consuming, and expensive, which cannot meet the needs of eye disease patients for long-term daily wear, greatly limiting their promotion in portable and everyday applications.

[0004] Upconversion luminescent materials can convert near-infrared light into high-energy visible light through nonlinear processes such as multiphoton absorption, making them an important material foundation for the development of portable infrared visualization devices. However, existing upconversion devices generally suffer from the following limitations: First, their single-pass absorption efficiency for weak infrared light is insufficient, resulting in a high infrared excitation threshold and difficulty in achieving effective upconversion in natural low-light scenarios. Second, upconversion materials are mostly used in the form of thin films, granular layers, or monolayer structures, lacking a mechanism for recovering and reusing the remaining infrared light that has not been absorbed after passing through the luminescent layer, leading to low infrared light utilization. Third, the effective loading capacity of rare-earth luminescent components is limited by the specific surface area of ​​the carrier material; existing solid nanosphere carriers have insufficient loading capacity, making it difficult to further improve the upconversion luminescence efficiency. Fourth, the brightness and uniformity of the visible light generated by upconversion are insufficient on the wearer's side, affecting the actual visual assistance effect.

[0005] In terms of device form, existing upconversion infrared visualization solutions mostly adopt contact lens structures. However, patients with RP and late-stage glaucoma often have complications such as decreased corneal sensitivity and poor tear film stability. Long-term wear of contact lenses can easily cause corneal damage, making them unsuitable for this special patient group. Integrating upconversion multi-layer optical structures into frame lenses is a better alternative. However, existing technologies still have the following problems in constructing multi-layer optical enhancement structures within a limited lens thickness: poor compatibility of multi-layer structure fabrication processes, easy aggregation of microspheres in the matrix leading to enhanced scattering, and difficulty in achieving uniform and stable spreading and interlayer bonding of each functional layer, which limits the engineering realization of frame-based upconversion glasses.

[0006] Therefore, there is an urgent need to develop a frame-type upconversion infrared visualization glasses that can stably integrate multi-layer optical enhancement structures within the thickness of ordinary frame lenses, significantly improve rare earth loading and upconversion efficiency, enable multiple uses of infrared light, and effectively enhance the brightness and uniformity of visible light on the wearer's side, so as to meet the visual assistance needs of patients with RP and late-stage glaucoma in low-light environments. Summary of the Invention

[0007] In view of this, the present invention provides a frame-type upconversion infrared visualization glasses, its preparation method, and its application. The present invention constructs a UCL with mesoporous SiO2 nanospheres as the core, and combines it with IRT, VGL, IRL, and PCL to form a five-layer optical enhancement structure. This structure is integrated into a frame lens using a layer-by-layer injection molding and graded curing process. This achieves multiple recycling of near-infrared light, efficient loading of rare-earth luminescent components, a significant improvement in upconversion luminescence efficiency, and a synergistic enhancement of the brightness and uniformity of visible light output on the wearer side. It has broad application prospects in the field of visual assistance for patients with retinitis pigmentosa and late-stage glaucoma.

[0008] The first aspect of the present invention is to provide a frame-type upconversion infrared visualization glasses, wherein the optical lens of the glasses comprises, from the incident side to the wearer side, an infrared anti-reflection layer (IRT), an upconversion core-shell emitting layer (UCL), a visible light gain layer (VGL), an infrared reflective layer (IRL), and a protective layer (PCL). The IRT is a hollow SiO2 nanosphere layer, used to improve the transmission efficiency of external incident infrared light entering the optical sheet. The UCL comprises a core-shell structure consisting of mesoporous SiO2 nanospheres as the core, coated with rare earth element-doped oxides, fluorides, or halide oxides, accounting for 15-25 wt.% of the total UCL. The shell thickness is 30-65 nm. The mesoporous SiO2 nanospheres have a particle size of 150-400 nm and a pore size of 5-15 nm. The mesoporous SiO2 has a high specific surface area, which is used to increase the loading of rare earth dopant and enhance the upconversion luminescence efficiency. The UCL is used to convert infrared light into visible light. The rare earth element is at least one of Y, Er, Yb, Tm, or Ho. The VGL is composed of a hybrid system of fluorescent polymer microspheres and light-diffusing microspheres. The fluorescent polymer microspheres are used for secondary emission or brightness enhancement of visible light generated by upconversion, while the light-diffusing microspheres are used for scattering and redistributing visible light to synergistically enhance the intensity and uniformity of visible light on the wearer's side. The fluorescent polymer microspheres are polymer microspheres doped with fluorescent groups or fluorescent dyes, and the light-diffusing microspheres are inorganic or organic microspheres with different refractive indices, used for multi-directional scattering of visible light. The mass ratio of fluorescent polymer microspheres to light-diffusing microspheres is 1:(0.2-5), preferably 1:(0.5-3). A higher proportion of fluorescent polymer microspheres can increase the intensity of secondary emission of visible light; a higher proportion of light-diffusing microspheres can enhance the light scattering and light path redistribution effects, thereby achieving a balance between brightness enhancement and light field uniformity. The IRL is a solid SiO2 nanosphere layer used to reflect unabsorbed infrared light back to the UCL, so as to realize the secondary utilization of infrared light. The PCL is a transparent polymer layer or a transparent composite layer containing nanofillers, disposed on the side close to the wearer, for optical adjustment and physical protection of the optical lens to meet the wearing stability and durability requirements of frame glasses; the transparent polymer is at least one of acrylate resin, polymethyl methacrylate (PMMA), polycarbonate (PC) or copolymers thereof; the nanofiller is at least one of SiO2, Al2O3 or ZnO nanoparticles, and the amount of the nanofiller is 0.1-5 wt.% of the mass of the transparent polymer.

[0009] Preferably, in the UCL, the shell thickness of the core-shell structure is 30-65 nm, the particle size of the mesoporous SiO2 nanospheres is 150-400 nm, and the pore size is 5-15 nm; the rare earth element is at least one of Y, Er, Yb, Tm, and Ho.

[0010] Preferably, in the VGL, the light-diffusing microspheres are TiO2@SiO2 core-shell structured microspheres, wherein the particle size of the TiO2 core is 80-200 nm, the thickness of the SiO2 shell is 10-50 nm, and the total particle size of the TiO2@SiO2 core-shell structured microspheres is 120-260 nm.

[0011] Preferably, the PCL further comprises a blue light blocking component, which is at least one of benzotriazole, benzophenone, or triazine optical absorbers. The amount of the blue light blocking component is 0.1-3.0 wt.%, more preferably 0.3-1.5 wt.%, of the mass of the transparent polymer in the PCL, to achieve effective absorption of high-energy blue light bands while maintaining good light transmission performance of the lens in the visible light range.

[0012] Preferably, the thicknesses of each functional layer in the optical film are: IRT 20-150 μm, UCL 50-200 μm, VGL 30-200 μm, IRL 20-200 μm, PCL 10-100 μm, and the overall lens thickness does not exceed 1.2 mm.

[0013] Preferably, the optical lens is embedded in a frame-type eyeglass frame with a radius of curvature of 60-140 mm, the edge compressive strength of the lens is greater than 90 MPa, the surface deviation after curing is less than ±0.05 mm, and the surface hardness of PCL is 2-3 H.

[0014] A second aspect of the present invention is to provide a method for manufacturing the above-mentioned frame-type upconversion infrared visualization glasses, comprising the following steps: S1. Preparation of mesoporous upconversion core-shell luminescent microspheres: Mesoporous SiO2 nanospheres are prepared, and with them as the core, their high specific surface area is utilized to coat the outer surface with at least one rare earth element-doped oxide, fluoride or halide oxide through a solvothermal reaction to form upconversion core-shell luminescent microspheres. S2. Preparation of microsphere dispersion systems for each functional layer: Hollow nanospheres, upconversion core-shell luminescent microspheres obtained in step S1, fluorescent polymer microspheres, light-diffusing microspheres, solid nanospheres, and transparent polymer dissolution or transparent polymer containing nanofillers are ultrasonically dispersed in acrylate resin monomer solutions. Initiators are added to each of the above systems to obtain the corresponding IRT, UCL, VGL, IRL, and PCL dispersion systems. S3. Forming a three-layer composite structure of UCL-VGL-IRL: The upconversion core-shell luminescent microsphere dispersion is placed in a frame-type eyeglass mold, and the mold is closed and pre-cured in the intermediate optical zone between the predetermined incident side and the wearer side to form UCL; then, a VGL dispersion containing fluorescent polymer microspheres and light-diffusing microspheres is added to the wearer side of the UCL, and the mold is closed and pre-cured to form VGL; then, an IRL dispersion is added to the wearer side of the VGL, and the mold is closed again and pre-cured by heating to form a three-layer composite structure of UCL-VGL-IRL. S4. Forming a complete five-layer optical structure: In the three-layer composite structure obtained in step S3, an IRT is formed on the outer side of the UCL side, i.e., the incident side of the entire optical structure; at the same time, on the outer side of the IRL side, i.e., the side closer to the wearer, a continuous cover layer is formed by spin coating, casting, or molding, and then cured to form a PCL; after photocuring and heat curing, a five-layer optical structure including IRT, UCL, VGL, IRL and PCL is obtained from the incident side to the wearer side, so that it can be stably embedded in the frame-type upconversion infrared visualization glasses.

[0015] Preferably, in step S1, the mesoporous SiO2 nanospheres are prepared using the Stöber method, with a particle size of 100-500 nm; the solvothermal reaction is carried out at 180-250°C, and the solvent is at least one of octadecene, oleic acid, oleylamine, liquid paraffin, ethanol, and water. By controlling the reaction time and precursor concentration, the thickness of the resulting core-shell structure is 30-65 nm; the rare earth element is at least one of Y, Er, Yb, Tm, and Ho.

[0016] Preferably, in step S2, the acrylate solution is at least one of hydroxyethyl methacrylate (HEMA), poly(ethylene glycol) methyl ether methacrylate (PEGMEMA), and ethylene glycol dimethacrylate (EGDMA).

[0017] Preferably, in step S2, the fluorescent polymer microspheres are polymer microspheres doped with fluorescent groups or fluorescent dyes, and their structure is a microsphere structure with a polymer matrix as the main body and luminescent centers introduced into the interior or surface. The polymer matrix is ​​preferably at least one of polymethyl methacrylate (PMMA), polyhydroxyethyl methacrylate (PHEMA), or copolymers thereof; the luminescent centers are preferably rare earth complexes or organic fluorescent dyes, so as to balance visible light enhancement effect and lens transparency.

[0018] More preferably, in step S2, the fluorescent polymer microspheres are prepared by suspension polymerization or emulsion polymerization. Specifically, the preparation method is as follows: an oil phase is formed by mixing methyl methacrylate (MMA) and ethylene glycol dimethacrylate (EGDMA) at a mass ratio of 95:5, and a rare earth luminescent complex Eu(BFA)3(TPPO)2, accounting for 3% of the total monomer mass, is added. The mixture is then reacted in an aqueous phase containing polyvinylpyrrolidone (PVP) dispersant at 70°C under nitrogen protection for 12 hours to obtain Eu microspheres with a particle size of 5 μm. 3+ Doped fluorescent polymer microspheres.

[0019] Preferably, in step S2, the initiator is a thermal initiator or a photoinitiator. The thermal initiator is azobisisobutyronitrile (AIBN) or benzoyl peroxide (BPO), and its amount is 0.1-2.0 wt.% of the total mass of the dispersion system. The photoinitiator is 1-hydroxycyclohexylphenyl ketone or 2,4,6-trimethylbenzoyl diphenylphosphine oxide (TPO), and its amount is 0.1-3.0 wt.% of the total mass of the dispersion system.

[0020] Preferably, in step S2, the light-diffusing microspheres are TiO2@SiO2 core-shell microspheres, which are prepared by forming a continuous SiO2 coating layer on the surface of TiO2 microparticles through a sol-gel coating method.

[0021] Preferably, in step S2, the mass fraction of microspheres in each microsphere dispersion system is 5-35 wt.%, more preferably 8-25 wt.%; the dispersion is performed using ultrasonic-assisted dispersion with a frequency of 20-40 kHz and a power of 100-600 W, the dispersion time is 5-30 min, and the system temperature is controlled by ice bath or circulating cooling.

[0022] Preferably, the pre-curing temperature in step S3 is 50-80℃, and the pre-curing time is 0.5-6 h.

[0023] Preferably, the heating and curing temperature in step S4 is 100-120℃, and the curing time is 2-8 h.

[0024] Preferably, a concave mold with a radius of curvature of 60-140 mm is used during molding, the viscosity of the acrylate matrix is ​​controlled at 80-120 mPa·s, and the liquid is fully spread by rotating at a low speed of 20-40 rpm for 5-8 minutes before curing.

[0025] A third aspect of the present invention is to provide the above-mentioned frame-type upconversion infrared visualization glasses for night vision assistance, driving assistance, low-light environment observation, security patrol, or visual enhancement in smoky environments.

[0026] Compared with the prior art, the beneficial technical effects of the present invention are as follows: This invention uses mesoporous SiO2 nanospheres with high specific surface area and ordered pore structure as the core carrier of upconversion core-shell structure. Compared with solid SiO2 microsphere carrier, the mesoporous structure provides a larger effective loading space for rare earth luminescent components, significantly improving the rare earth doping amount, thereby enhancing the absorption capacity of UCL for near-infrared light and the upconversion luminescence efficiency from the material level.

[0027] The present invention effectively improves the transmittance of external infrared light into the lens by using IRT, while IRL reflects the remaining infrared light that was not absorbed in the first exposure back to UCL for secondary excitation, thereby greatly improving the overall utilization efficiency of infrared light and reducing the infrared light power threshold required for effective excitation, so that the device can work normally in natural low light environment.

[0028] This invention introduces VGL between UCL and IRL, wherein fluorescent polymer microspheres perform secondary emission and energy enhancement of visible light generated by upconversion, and light-diffusing microspheres perform multi-directional scattering and light path redistribution of visible light. The two types of microspheres work together to improve the overall visible light output brightness on the wearer's side while effectively improving the spatial uniformity of brightness and enhancing the actual visual aid quality.

[0029] This invention integrates a multi-layer optical structure into a frame-type eyeglass lens, eliminating the need for direct contact with the cornea. This fundamentally avoids the risks associated with contact lenses, such as decreased corneal sensitivity and poor tear film stability in patients with retinopathy of prematurity (RP) and advanced glaucoma, making it suitable for long-term daily wear. Furthermore, the PCL (polycrystalline lens) design provides both physical protection and optional blue light blocking, further meeting the requirements for comfort and durability in frame-type eyeglasses.

[0030] Each functional layer of this invention is based on a dispersion system of microspheres dispersed in acrylate monomers. It is sequentially formed in a frame-type lens mold through layer-by-layer injection molding and graded curing processes. The interlayer bonding is stable, curing shrinkage is controllable, and the thickness of each functional layer is precise with minimal surface deviation. The resulting lenses can be directly embedded in standard eyeglass frames. The ultrasonic-assisted dispersion, low-speed rotational leveling, and graded curing processes effectively suppress microsphere aggregation and interlayer scattering, ensuring the uniformity and long-term stability of each optical layer. The overall fabrication process has good controllability and promising prospects for large-scale application. Attached Figure Description

[0031] The present invention will be further described below with reference to the accompanying drawings.

[0032] Figure 1 This is a schematic diagram of the overall appearance structure of the frame-type upconversion infrared visualization glasses of the present invention; Figure 2 This is a schematic diagram of the five-layer functional structure of the optical lens of the frame-type upconversion infrared visualization glasses of the present invention and the composition of each layer of microspheres; Figure 3This is a schematic diagram illustrating the working principle and optical path propagation of the infrared-to-visible light conversion of the frame-type upconversion infrared visualization glasses of the present invention. Detailed Implementation

[0033] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0034] Unless otherwise specified, all experiments were repeated three times, and the results are expressed as averages.

[0035] Example 1: A five-layer upconversion lens based on a mesoporous SiO2 core and a NaYF4:Yb,Er shell. 1. Preparation of mesoporous SiO2 nanospheres SiO2 microspheres with a particle size of 220 nm were prepared using the Stöber method, and the specific method is as follows: 20 mL of TEOS was added dropwise to an ethanol / ammonia solution (volume ratio 15:1), and the mixture was magnetically stirred at room temperature for 6 h. The resulting microspheres were washed three times by centrifugation at 8000 rpm for 10 min and dried in an oven at 60 °C for 12 h to obtain mesoporous SiO2 nanospheres with a particle size of 220 nm and a pore size of 9 nm. Transmission electron microscopy (TEM) characterization showed that the prepared microspheres had good sphericity, a particle size distribution standard deviation of <5%, and exhibited mesoporous structure characteristics. 2. Preparation of upconversion core-shell structured microspheres 0.20 g of the above mesoporous SiO2 microspheres were added to a mixed solvent of oleic acid / octadecene (volume ratio 3:2), and heated to 140℃ under nitrogen protection for 30 min to remove adsorbed moisture. An ethanol solution of YCl3, YbCl3, and ErCl3 (molar ratio 40:20:1) was added, stirred until homogeneous, and then NH4F and NaOH precursors were added. A solvothermal reaction was carried out at 200℃ for 16 h. After ethanol precipitation and centrifugation washing, NaYF4:Yb,Er@mesoporous SiO2 core-shell microspheres with a shell thickness of 45 nm were obtained. TEM analysis showed that its crystal structure was hexagonal NaYF4. Under 980 nm laser excitation, the microspheres produced typical green (550 nm) and red (660 nm) emission peaks, and the upconversion luminescence intensity met the requirements for further construction of a lens structure. 3. Preparation of five types of functional layer dispersion systems 3.1 UCL Dispersion System NaYF4:Yb,Er@mesoporous SiO2 core-shell microspheres were added at 15 wt.% to a HEMA / EGDMA (mass ratio 9:1) system, and 0.8 wt.% AIBN was added. The mixture was treated with ultrasonic at 30 kHz and 300 W for 20 min to obtain a uniform dispersion. 3.2 VGL Dispersion System Fluorescent polymer microspheres and light-diffusing microspheres (TiO2@SiO2 core-shell structure microspheres with a particle size of 120 nm, a SiO2 shell thickness of 20 nm, and a total particle size of 160 nm. This core-shell structure achieves visible light scattering through the refractive index difference between the high-refractive-index TiO2 core and the low-refractive-index SiO2 shell. At the same time, the SiO2 shell can improve the dispersion stability of the microspheres in the resin system) were added to a HEMA matrix containing photoinitiator TPO to form a mixed dispersion system. The total mass fraction of microspheres was 12 wt.%, the mass ratio of fluorescent polymer microspheres to light-diffusing microspheres was 1:1.5, and the mass fraction of photoinitiator was 1 wt.%. The microspheres were dispersed under ultrasonic conditions of 30 kHz and 300 W for 20 min and then set aside for later use. The fluorescent polymer microspheres were prepared as follows: An oil phase was formed by mixing MMA and EGDMA at a mass ratio of 95:5, and a rare earth luminescent complex Eu(BFA)3(TPPO)2, accounting for 3% of the total monomer mass, was added. The mixture was then reacted in an aqueous phase containing PVP dispersant at 70°C under nitrogen protection for 12 h to obtain Eu microspheres with a particle size of 5 μm. 3+ Doped fluorescent polymer microspheres; 3.3 IRL Dispersion System 200 nm solid SiO2 microspheres were dispersed at 20 wt.% in a HEMA / EGDMA (mass ratio 9:1) matrix to form an IRL, and a thermal initiator AIBN was added at an amount of 0.8 wt.% of the total mass of the dispersion system. 3.4 IRT Dispersion System Hollow SiO2 microspheres with a particle size of 250 nm and a shell thickness of 30 nm were used, dispersed at a concentration of 8 wt.%, and photoinitiator TPO was added at an amount of 0.1 wt.% of the total mass of the dispersion system. 3.5 PCL (PCL) Dispersion / Coating System The PCL is a transparent composite layer containing nanofillers. The transparent composite layer is a cross-linked resin system formed by HEMA and EGDMA, wherein the mass ratio of HEMA to EGDMA is 9:1. The nanofiller is SiO2 with a particle size of 20 nm, added at 1 wt.% of the total mass of the transparent resin, used to improve the abrasion resistance and mechanical stability of the lens surface. The PCL also contains a blue light blocking component, which is a benzotriazole-based UV / blue light absorber, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole (UV-P), added at 0.5 wt.% of the total mass of the transparent resin. 4. Multi-layer structure molding and curing 4.1 Mold curvature and leveling pretreatment A concave mold with a radius of curvature R=100 mm was used to control the viscosity of the acrylate matrix at 100 mPa·s, and the liquid was fully spread by rotating at a low speed of 30 rpm for 6 min before curing. 4.2 Constructing the UCL (UCL) The UCL dispersion was injected into the mold, and after the mold was closed, it was placed on a 65℃ heating plate for pre-curing for 4.5 h. The resulting UCL thickness was 90 μm and the interface was smooth. 4.3 Constructing a three-layer composite structure of UCL-VGL-IRL After opening the mold, VGL and IRL dispersions are injected sequentially, the mold is closed again, and pre-cured at 70℃ for 4 hours; the curing shrinkage is controlled at <4% to reduce the risk of delamination of the curved structure; 4.4 Constructing the incident-side IRT and the wear-side PCL IRT dispersion was coated on the incident side and cured with 395 nm UV light for 30 min; PCL was formed on the side close to the wearer and finally cured at 110℃ for 4 h; the final five-layer structure has a total thickness of 1.05 mm, a surface deviation of <±0.05 mm, can be embedded in the frame-type eyeglass slot, the lens edge compressive strength is 95 MPa, and the PCL surface hardness is 2H. 5. Optical and mechanical performance testing 5.1 Upconversion luminescence performance The luminescence performance of the five-layer structure lens prepared in this embodiment was tested under 980 nm laser excitation. The test results show that, compared with a single-layer structure containing only UCL, the visible light luminescence intensity of the multilayer structure lens of this invention is increased by 2.3 times (130%). This enhancement mainly comes from the improved infrared light incident efficiency by IRT, the secondary utilization of unabsorbed infrared light by IRL, and the synergistic effect of VGL on secondary emission and optical path redistribution of visible light. Meanwhile, the emission peaks in each band remain intact, with the main emission peaks located at 550 nm (green light) and 660 nm (red light). VGL did not introduce significant spectral peak distortion or additional stray peaks, indicating that the multilayer structure does not adversely affect the upconversion luminescence process. 5.2 Frame Assembly Durability Test The lenses were assembled into the TR90 eyeglass frame and subjected to 500 simulated loading and unloading cycles. The clamping force was controlled at 6 N, and the lenses showed no cracks or delamination. 5.3 Transparency Test The average transmittance of the lens in the 400-700 nm range was measured to be 85%, which meets the needs of daily wear of framed glasses.

[0036] Example 2: A blue light upconversion lens based on a mesoporous SiO2 core-NaGdF4:Yb,Tm shell The difference from Example 1 is as follows: 1. Mesoporous SiO2 microspheres with a particle size of 180 nm were prepared using the Stöber method, the preparation method being the same as in Example 1. The resulting microspheres had a pore size of 9 nm. 2. Preparation of upconversion core-shell structured microspheres 0.20 g of mesoporous SiO2 microspheres were added to an oleic acid system. The mixture was heated to 140 °C under nitrogen protection and held for 30 min to remove adsorbed moisture. Then, NaGdF4 precursor and Yb / Tm dopant ions were added, controlling the Gd:Yb:Tm ratio to be 40:28:1. The mixture was subjected to a solvothermal reaction at 220 °C for 14 h in the oleic acid system. After the reaction, the microspheres were precipitated with ethanol and washed by centrifugation to obtain NaGdF4:Yb,Tm@mesoporous SiO2 core-shell microspheres with a shell thickness of 40 nm. These microspheres produced a distinct blue upconversion emission peak under 980 nm excitation, with the emission wavelength located in the range of 450-480 nm. 3. Preparation of five types of functional layer dispersion systems The preparation methods of each layer of the dispersion system are basically the same as those in Example 1, with only adjustments made to the amount of microspheres added.

[0037] 3.1 UCL Dispersion System The amount of UCL microspheres added was increased to 18 wt.%; 3.2 VGL Dispersion System Total VGL microsphere content: 15 wt.% (mass ratio of fluorescent polymer microspheres to light-diffusing microspheres 1:1.5) 3.3 The pre-curing temperature is raised to 70℃.

[0038] 4. Multi-layer structure molding Following the method described in Example 1, a five-layer structure of IRT-UCL-VGL-IRL-PCL was constructed sequentially and then cured. The final five-layer structure has a total thickness of 1.05 mm, a surface deviation of <±0.05 mm, can be embedded in the metal frame slot, has an edge compressive strength of 95 MPa, and a PCL surface hardness of 3 H.

[0039] 5. Optical and mechanical performance testing 5.1 Upconversion luminescence performance Under 980 nm laser excitation, the lens produces significant blue light emission (450-480 nm), with the luminescence intensity being 2.1 times higher than that of a single-layer UCL structure.

[0040] 5.2 Frame Assembly Durability Test The prepared lens was installed into a metal frame and subjected to 300 bending tests. The lens structure remained intact and there was no interlayer slippage, making it suitable for visual enhancement in low-light environments. After 500 simulated loading and unloading cycles (clamping force 6 N), the lens showed no cracks or interlayer delamination. The average transmittance of the lens in the 400-700 nm range was measured to be 84%, which meets the needs of daily wear with a frame.

[0041] Example 3: A red-green dual-enhancing lens based on a mesoporous SiO2 core-NaYF4:Yb,Ho shell The difference from Example 1 is as follows: 1. Preparation of mesoporous SiO2 nanospheres Mesoporous SiO2 microspheres with a particle size of 260 nm and a pore size of 9 nm were prepared using the Stöber method, and the preparation method was the same as in Example 1.

[0042] 2. Preparation of upconversion core-shell structured microspheres The aforementioned mesoporous SiO2 microspheres were added to an oleylamine system and dehydrated at 140℃ for 30 min. Subsequently, NaYF4 precursor and Yb / Ho dopant ions were added, controlling the Y:Yb:Ho ratio to be 40:20:1, and a solvothermal reaction was carried out at 190℃ for 18 h to obtain NaYF4:Yb,Ho@mesoporous SiO2 core-shell microspheres with a shell thickness of 55 nm. Under 980 nm laser excitation, the microspheres produced emission peaks of 540 nm green light and 650 nm red light, achieving red-green dual-band upconversion luminescence.

[0043] 3. Functional Layer Distributed System The preparation method of each layer of the dispersion system is the same as in Example 1, only the microsphere ratio is adjusted. The proportions of each microsphere were adjusted as follows: IRT hollow microspheres 10 wt.%; UCL core-shell microspheres 15 wt.%; VGL (fluorescent polymer microspheres + light-diffusing microspheres) 20 wt.%; IRL solid microspheres 20 wt.%; PCL is a transparent polymer system. The pre-curing temperature is 68℃; the final curing temperature is 105℃×6 h.

[0044] The final five-layer structure has a total thickness of 1.05 mm, a surface deviation of <±0.05 mm, and can be embedded in nylon thread semi-rimless glasses. The edge compressive strength of the lens is 96 MPa, and the surface hardness of PCL is 3 H.

[0045] After the prepared lens was embedded into the nylon thread semi-rimless glasses, a stress test was conducted for 48 hours, and no optical layer detachment was observed. The frame underwent 300 bending tests, and the lens structure remained intact without interlayer slippage, making it suitable for visual enhancement in low-light environments. After 500 simulated loading and unloading cycles (clamping force 6 N), the lens showed no cracks or interlayer delamination. The average transmittance of the lens in the 400-700 nm range was measured to be 83%, meeting the needs of daily wear of framed glasses.

[0046] Example 4: A broadband response lens based on a mesoporous SiO2 core-NaGdF4:Yb,Er shell The difference from Example 1 is as follows: 1. Preparation of mesoporous SiO2 nanospheres Mesoporous SiO2 microspheres with a particle size of 220 nm and a pore size of 9 nm were prepared using the Stöber method, and the preparation method was the same as in Example 1.

[0047] 2. Preparation of upconversion core-shell structured microspheres The above-mentioned mesoporous SiO2 microspheres were added to an oleic acid system and dehydrated at 140℃ for 30 min. Then, NaGdF4 precursor and Yb / Er dopant ions were added, and the ratio of Gd:Yb:Er was controlled to be 40:20:1. The reaction was carried out at 210℃ for 15 h of solvothermal reaction to obtain NaGdF4:Yb,Er@mesoporous SiO2 core-shell microspheres with a shell thickness of 45 nm. Under 980 nm laser excitation, the core-shell microspheres produce distinct green (550 nm) and red (660 nm) light emission.

[0048] 3. Functional Layer Distributed System The preparation method of each layer of the dispersion system is the same as in Example 1, except that the following parameters are adjusted: the amount of UCL microspheres added is 25 wt.%; The parameters of the remaining functional layer dispersion system remain consistent with those of Example 1.

[0049] 4. Multi-layer structure molding The five-layer structure IRT-UCL-VGL-IRL-PCL is constructed sequentially according to the method in Example 1.

[0050] The pre-curing temperature is 75℃ for 3.5 hours, and the final curing temperature is 120℃ for 4.5 hours.

[0051] The final five-layer structure has a total thickness of 1.05 mm, a surface shape deviation of <±0.05 mm, a lens edge compressive strength of 97 MPa, and a PCL surface hardness of 3 H.

[0052] 5. Optical performance testing The optical response of the five-layer lens fabricated in this embodiment was tested under 980 nm laser excitation. The average transmittance of the lens in the 400-700 nm range was measured to be 83%. The results show that compared with a single-layer structure containing only UCL, the optical response intensity of the lens in this embodiment is increased by 2.6 times in the near-infrared band. Simultaneously, the visible light emission intensity output by the lens is increased by 2.4 times. This enhancement mainly comes from the IRT improving the near-infrared light incident efficiency, the IRL enabling the secondary utilization of unabsorbed infrared light, and the synergistic effect of VGL in the secondary emission and optical path redistribution of visible light. Spectroscopic tests show that the lens has a stable response in the 850-1100 nm near-infrared band, and its infrared light absorption and utilization efficiency is 45% higher than that of a single-layer UCL structure. In low-light environment simulation tests, the wearer can observe a significantly enhanced visible light output, thereby improving visual perception at night or in low-light environments.

[0053] Therefore, this embodiment achieves enhanced response to the near-infrared band by regulating the shell system and the intralayer recycling mechanism, making it suitable for nighttime and low-light observation scenarios.

[0054] Example 5 The difference from Example 1 is as follows: By adjusting the ratio of template agent to silicon source, mesoporous SiO2 nanospheres with an average pore size of 3.5 nm were prepared, and the overall particle size was controlled to be 220 nm.

[0055] NaYF4:Yb,Er@mesoporous SiO2 core-shell microspheres were prepared using the mesoporous SiO2 microspheres as the core, and a five-layer structure lens was constructed according to the method in Example 1.

[0056] Performance test results show that, compared with the mesoporous SiO2 core sample with a pore size of 9 nm in Example 1, the upconversion luminescence intensity of the sample in this example is reduced by 40%. Energy dispersive spectroscopy (EDS mapping) analysis shows that the distribution of rare earth luminescent components within the mesoporous structure is significantly limited, mainly concentrated on the outer surface of the pores. Experimental results indicate that when the pore size of mesoporous SiO2 is less than 5 nm, the pore size is insufficient to effectively accommodate rare earth precursors or luminescent components entering the mesopore, thereby reducing the rare earth loading and limiting the effective distribution of luminescent centers, leading to a significant decrease in upconversion efficiency. Therefore, the lower limit of the mesoporous SiO2 pore size is set at 5 nm.

[0057] Example 6 The difference from Example 1 is that a pore size expander was introduced to prepare mesoporous SiO2 nanospheres with an average pore size of 20 nm and an overall particle size of 220 nm.

[0058] NaYF4:Yb,Er@mesoporous SiO2 core-shell microspheres were prepared using the mesoporous SiO2 microspheres as the core, and a five-layer structure lens was constructed according to the method in Example 1.

[0059] Performance test results show that, compared with the mesoporous SiO2 core sample with a pore size of 9 nm in Example 1, the upconversion luminescence intensity of the sample in this example under 980 nm laser excitation is only increased by 3%, a negligible improvement. Simultaneously, the average transmittance of the lens in the 400-700 nm visible light band decreases by 10%, and a significant increase in light scattering is observed. This indicates that when the mesoporous pore size exceeds 15 nm, although the rare earth loading is no longer limited, the excessively large pore structure introduces additional light scattering and weakens the stability of the mesoporous framework, thus negatively impacting the lens's transparency and structural reliability. Therefore, the upper limit for the mesoporous SiO2 pore size is limited to 15 nm.

[0060] Example 7 The difference from Example 1 is that: a mesoporous SiO2 core (9 nm pore size, 200 nm particle size) was used, and by reducing the precursor concentration and shortening the solvothermal reaction time, NaYF4:Yb,Er core-shell microspheres with an average shell thickness of 22 nm were prepared.

[0061] Performance test results show that, under 980 nm excitation conditions, the visible light emission intensity of this sample is 30% lower than that of the sample with a shell thickness of 45 nm, and it exhibits more significant luminescence attenuation in continuous excitation tests. Analysis suggests that when the shell thickness of the core-shell structure is less than 30 nm, the volume of rare-earth luminescent centers in the upconversion luminescent layer that can participate in energy transfer is insufficient, making it difficult to form a stable and efficient infrared absorption and luminescence system, thus leading to reduced luminescence efficiency and decreased stability. Therefore, the lower limit of the shell thickness of the upconversion core-shell structure is set at 30 nm.

[0062] Example 8 The difference from Example 1 is that two sets of comparative lens samples with different structures were prepared. Sample A is the structure of the present invention, which includes a five-layer structure of IRT-UCL-VGL-IRL-PCL, wherein VGL is composed of fluorescent polymer microspheres and TiO2@SiO2 light-diffusing microspheres. Sample B is a control sample. While keeping other material systems, microsphere ratios and process conditions completely consistent, the VGL layer was removed, leaving only the four-layer structure of IRT-UCL-IRL-PCL.

[0063] The visible light output intensity and brightness distribution on the wearer side were tested under the same 980 nm excitation conditions. The results showed that the visible light brightness of sample A was 48% higher than that of sample B, and the brightness uniformity was significantly improved. The brightness distribution test showed that the brightness difference between the center and the edge of sample A was reduced by 32%.

[0064] It is evident that VGL, through the synergistic effect of fluorescence enhancement and light diffusion, enables secondary utilization and spatial redistribution of visible light generated by upconversion. This is a key structural feature for improving output brightness and uniformity, distinguishing it from existing technologies that rely solely on a single upconversion emitting layer.

[0065] Comparative Example 1 This comparative example is used to compare the effects of solid SiO2 microspheres and mesoporous SiO2 microspheres as the core of the upconversion core-shell structure on rare earth loading capacity and upconversion luminescence performance, so as to directly compare the solid microsphere structure used in the prior art CN 121325436 A.

[0066] Two sets of upconversion core-shell microspheres were prepared: Sample C (comparative example) used solid SiO2 nanospheres as the core with a particle size of 220 nm; Sample D (control of this invention) used mesoporous SiO2 nanospheres as the core with a particle size of 220 nm and a pore size of 9 nm. This structure is the same as the mesoporous SiO2 core structure used in Example 1. Both samples were coated with a NaYF4:Yb,Er shell on the surface of the microspheres under the same solvothermal conditions, with the shell thickness controlled at 45 nm, and the remaining preparation conditions were kept consistent.

[0067] IRT-UCL-VGL-IRL-PCL five-layer optical structure lenses were constructed using core-shell microspheres from samples C and D, respectively. The material systems, microsphere ratios, and curing processes of the remaining functional layers were kept consistent with those in Example 1.

[0068] The visible light output intensity of the lens was tested under 980 nm laser excitation. The results show that the upconversion luminescence intensity of sample D with a mesoporous SiO2 core is 58% higher than that of sample C with a solid SiO2 core. Energy dispersive spectroscopy analysis results show that the effective loading of rare earth luminescent components in the mesoporous SiO2 core sample is significantly higher than that in the solid microsphere sample.

[0069] Therefore, compared with the solid microsphere core structure used in the existing technology CN 121325436 A, using mesoporous SiO2 microspheres as the upconversion core can significantly improve the rare earth loading capacity and upconversion luminescence efficiency.

[0070] Comparative Example 2 This comparative example is used to compare the effects of different hollow microsphere materials as IRT (Infrared Radiance Reduction) on infrared incident efficiency and lens stability, in order to verify the rationality of the present invention in selecting hollow SiO2 microspheres.

[0071] Two sets of lens samples were prepared, differing only in the IRT material: Sample E (comparative example) used hollow ZnO microspheres for IRT; Sample F (structure of this invention) used hollow SiO2 microspheres for IRT, with the same structure as the IRT structure in Example 1. The structure of all other layers was IRT-UCL-VGL-IRL-PCL, and the material system, microsphere ratio, and curing process used for each functional layer were consistent with those in Example 1.

[0072] The infrared incident efficiency and visible light output performance of the lenses were tested under 980 nm laser irradiation. The test results showed that sample E, using hollow ZnO microspheres as the IRT (Infrared Reflectance Technology), had a transmittance of 76% in the near-infrared band, while sample F, using hollow SiO2 microspheres, had a transmittance of 84%. Simultaneously, under accelerated aging testing at 60℃ and 95% relative humidity for 72 h, the visible light luminescence intensity of sample E decreased by 18%, while that of sample F decreased by 6%. Analysis suggests that ZnO material exhibits certain photocatalytic activity under light irradiation, potentially promoting photo-oxidation of the resin matrix and thus reducing lens structural stability; while SiO2 material possesses better chemical stability and optical transparency. Therefore, compared to hollow ZnO microspheres, hollow SiO2 microspheres have better chemical stability and infrared transmittance, making them more suitable as IRT materials to ensure the optical stability and reliability of the lenses under long-term wear conditions.

[0073] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A frame-type upconversion infrared visualization glasses, characterized in that, The optical elements of the glasses, from the incident side to the wearer side, include an infrared anti-reflection layer (IRT), an upconversion core-shell luminescent layer (UCL), a visible light gain layer (VGL), an infrared reflective layer (IRL), and a protective layer (PCL). The IRT is a hollow SiO2 nanosphere layer; The UCL comprises a core-shell structure consisting of mesoporous SiO2 nanospheres as the core, coated with rare earth element-doped oxides, fluorides, or halide oxides, accounting for 15-25 wt.% of the total UCL; the rare earth element is at least one of Y, Er, Yb, Tm, or Ho. The VGL is composed of a mixture of fluorescent polymer microspheres and light-diffusing microspheres; the mass ratio of the fluorescent polymer microspheres to the light-diffusing microspheres is 1:(0.2-5); The IRL is a solid SiO2 nanosphere layer; The PCL is a transparent polymer layer or a transparent composite layer containing nanofillers.

2. The frame-type upconversion infrared visualization glasses according to claim 1, characterized in that, The VGL is composed of a mixture of fluorescent polymer microspheres and light-diffusing microspheres; the mass ratio of the fluorescent polymer microspheres to the light-diffusing microspheres is 1:(0.5-3).

3. The frame-type upconversion infrared visualization glasses according to claim 1, characterized in that, In the PCL, the transparent polymer is at least one of acrylate resin, polymethyl methacrylate, polycarbonate or copolymer thereof; the nanofiller is at least one of SiO2, Al2O3 or ZnO nanoparticles, and the amount of the nanofiller is 0.1-5 wt.% of the mass of the transparent polymer.

4. The frame-type upconversion infrared visualization glasses according to claim 1, characterized in that, In the UCL, the shell thickness of the core-shell structure is 30-65 nm, the particle size of the mesoporous SiO2 nanospheres is 150-400 nm, and the pore size is 5-15 nm; the rare earth element is at least one of Y, Er, Yb, Tm, and Ho.

5. The frame-type upconversion infrared visualization glasses according to claim 1, characterized in that, In the VGL, the fluorescent polymer microspheres are microsphere structures with a polymer matrix as the main body and luminescent centers introduced into the interior or surface. The polymer matrix is ​​at least one of polymethyl methacrylate, polyhydroxyethyl methacrylate, or copolymers thereof. The luminescent centers are preferably rare earth complexes or organic fluorescent dyes. The light-diffusing microspheres are TiO2@SiO2 core-shell structure microspheres, wherein the particle size of the TiO2 core is 80-200 nm, the thickness of the SiO2 shell is 10-50 nm, and the total particle size of the TiO2@SiO2 core-shell structure microspheres is 120-260 nm.

6. The frame-type upconversion infrared visualization glasses according to claim 1, characterized in that, The PCL also contains blue light blocking ingredients.

7. A frame-type upconversion infrared visualization glasses according to claim 1, characterized in that, The thicknesses of each functional layer in the optical film are as follows: IRT 20-150 μm, UCL 50-200 μm, VGL 30-200 μm, IRL 20-200 μm, PCL 10-100 μm, and the overall lens thickness does not exceed 1.2 mm.

8. The method for manufacturing the frame-type upconversion infrared visualization glasses according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Preparation of mesoporous upconversion core-shell luminescent microspheres: Mesoporous SiO2 nanospheres are prepared, and rare earth element-doped oxides, fluorides or halide oxides are coated on their outer surface through a solvothermal reaction to form upconversion core-shell luminescent microspheres. S2. Preparation of microsphere dispersion systems for each functional layer: Hollow nanospheres, upconversion core-shell luminescent microspheres obtained in step S1, fluorescent polymer microspheres, light-diffusing microspheres, solid nanospheres, and transparent polymer dissolution or transparent polymer containing nanofillers are ultrasonically dispersed in acrylate resin monomer solutions. Initiators are added to each of the above systems to obtain the corresponding IRT, UCL, VGL, IRL, and PCL dispersion systems. S3. Forming a three-layer composite structure of UCL-VGL-IRL: The upconversion core-shell luminescent microsphere dispersion is placed in a frame-type eyeglass mold, and the mold is closed and pre-cured in the intermediate optical zone between the predetermined incident side and the wearer side to form UCL; then, a VGL dispersion containing fluorescent polymer microspheres and light-diffusing microspheres is added to the wearer side of the UCL, and the mold is closed and pre-cured to form VGL; then, an IRL dispersion is added to the wearer side of the VGL, and the mold is closed again and pre-cured by heating to form a three-layer composite structure of UCL-VGL-IRL. S4. Forming a complete five-layer optical structure: In the three-layer composite structure obtained in step S3, an IRT is formed on the outer side of the UCL side, i.e., the incident side of the entire optical structure; at the same time, on the outer side of the IRL side, i.e., the side closer to the wearer, a continuous cover layer is formed by spin coating, casting, or molding, and then cured to form a PCL; after photocuring and heat curing, a five-layer optical structure is obtained from the incident side to the wearer side, including IRT, UCL, VGL, IRL, and PCL in sequence.

9. The preparation method according to claim 8, characterized in that, During molding, a concave mold with a radius of curvature of 60-140 mm is used. The viscosity of the acrylate matrix is ​​controlled at 80-120 mPa·s. Before curing, the mold is rotated at a low speed of 20-40 rpm for 5-8 minutes to allow the liquid to spread fully.

10. The application of the frame-type upconversion infrared visualization glasses according to any one of claims 1-7 in night vision assistance, driving assistance, low-light environment observation, security patrol or visual enhancement in smoke environment.

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