Production process of 6-degree free ring curved lens

Abstract

The invention discloses a production process of a 6-degree free ring curved surface lens, which is based on precise optometry, takes digital modeling as a core, realizes precise recarving of design through vacuum forming, combines surface strengthening and strict quality control, and improves the production efficiency of the 6-degree free ring curved surface lens. And finally, the high-quality lens with high-definition imaging, wide visual field and light and thin appearance is produced.

Description

Technical Field

[0001] This invention belongs to the field of lens manufacturing technology, specifically, it relates to a manufacturing process for a 6-degree free-form torus lens. Background Technology

[0002] 25-degree lenses are the standard specification in the eyewear industry. Their core feature is that they are designed, manufactured, and fitted with lenses based on a spherical power gradient of 0.25D (diopter). They are suitable for the vision correction needs of most people with myopia, hyperopia, and astigmatism. However, 25-degree lenses cannot meet the needs of precision workers, high-end users with extremely high visual quality requirements, and people with high prescriptions. They need lenses with a lower gradient to meet their needs. 6-degree lenses have high quality, high-definition imaging, a wide field of vision, and a thin appearance, but their manufacturing process is more refined than that of 25-degree lenses. Summary of the Invention

[0003] In view of this, the technical problem to be solved by the present invention is to provide a manufacturing process for a 6-degree free-form torus lens, which solves the problem of the immaturity of the manufacturing process for 6-degree lenses in the prior art.

[0004] To address the aforementioned technical problems, this invention discloses a manufacturing process for a 6-degree free-form torus lens, the specific steps of which include: S1. Mold cleaning: Use a lint-free cloth dampened with anhydrous ethanol to wipe the inner surface of the free toroidal mold to remove dust, oil and other impurities, and to prevent pitting and scratches from appearing on the lens surface after molding. S2. Blank preparation: The cut resin blank is ultrasonically cleaned, dried and placed in the center of the mold to ensure that the blank is aligned with the positioning reference of the mold. S3. Mold closing: Close the lower mold and upper mold that hold the blank, place them into the cavity of the vacuum adsorption equipment, and lock the mold clamps. S4. Heating and softening: Heating rate: 5℃ / min; Holding temperature: 5℃ ± the softening point of the substrate; Holding time: 20~25min, using segmented heating (room temperature → 80℃ → softening point) to avoid stress inside the blank. S5. Vacuuming: Vacuum degree: ≤1Pa; Pressure holding time: 15~30min; Hold pressure for 30min, then activate real-time pressure compensation to ensure complete fit in complex curved areas (such as edge transition areas); S6. Cooling and curing: Cooling rate: 3℃ / min; Cooling endpoint: room temperature; Gradual cooling (softening point → 100℃ → 50℃ → room temperature) is used to eliminate internal stress in the resin and prevent surface springback. S7. Mold opening and part removal: After the mold temperature drops to room temperature, open the fixture and remove the formed lens blank. Check the surface for defects such as poor adhesion and bubbles. S8. Edge trimming: Remove excess material and positioning edges from the blank to obtain a preliminary free-form torus lens shape; S9. Stress testing: Use a polarizer to test the internal stress of the lens. Defective products need to be annealed again or scrapped. S10. Lens surface strengthening and coating: Apply a hardening coating to the lens surface using a UV hardening machine. Thickness: 3-5 μm, curing time: 30-60 s, coating hardness: ≥4H; Vacuum evaporation: 15-25 layers.

[0005] Furthermore, in step S2 above, the deviation of the alignment between the blank and the positioning reference of the mold is ≤ ±2μm.

[0006] Furthermore, the aforementioned resin material is polyurethane, and its softening temperature is 120–180°C.

[0007] Furthermore, in step S4 above, the heating and softening temperature is controlled at ±2℃ of the substrate softening point.

[0008] Furthermore, the vacuum-deposited film consists of 20 layers, which are distributed on the front and back surfaces of the lens.

[0009] Compared with the prior art, this application can achieve the following technical effects: The manufacturing process of the 6-degree free-form toroidal lens of this invention is based on accurate optometry, with digital modeling as the core. It achieves precise replication of the design through vacuum forming, combined with surface strengthening and strict quality control, and finally produces a high-quality lens that combines high-definition imaging, wide field of vision and thin appearance.

[0010] Of course, any product implementing this application does not necessarily need to achieve all of the technical effects described above at the same time. Detailed Implementation

[0011] The following will describe the implementation of this application in detail with reference to the embodiments, so that the implementation process of how this application uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0012] Preliminary preparation and parameter collection Precise refraction: Using a 6-degree spherical lens power gradient refraction (replacing the traditional 25-degree gradient), combined with subjective refraction, red-green balance, binocular balance, etc., to obtain accurate parameters such as spherical lens power, astigmatism, axis, etc., thereby improving the quality of retinal imaging.

[0013] Parameter collection for eyeglass fitting: Collect the geometric parameters of the frame (frame shape, size, pupillary distance, pupillary height) and the wearing parameters (forward tilt angle, face curvature, lens-to-eye distance). For some high-end custom designs, facial feature data will also be included to provide a basis for personalized design.

[0014] Material selection: Select an optical resin substrate with a suitable refractive index (such as MR series) according to the degree and application (such as daily use, blue light protection) to ensure optical performance and processing compatibility.

[0015] Optical Design and Digital Modeling Eye model construction: Based on optometry and lens fitting parameters, a simulation model containing the human eye's refractive system is constructed using optical software such as Zemax to simulate the light propagation path.

[0016] Free-form torus surface design: Adopting a double-sided free-form torus surface design, by adjusting thousands of free parameters, the curvature distribution of the front and rear surfaces of the lens is optimized point by point, eliminating peripheral astigmatism and distortion, and expanding the clear field of vision.

[0017] 6-degree gradient optimization: Using a 6-degree spherical lens power gradient, the refractive power of each area of ​​the lens is finely distributed to ensure that light is accurately focused on the retina and improve image clarity.

[0018] Simulation verification and iteration: The imaging effects of different fields of view and different angles are simulated by ray tracing technology, aberration data are analyzed, and the model is repeatedly optimized until the design standards are met.

[0019] A manufacturing process for a 6-degree free-form torus lens includes the following steps: S1. Mold cleaning: Use a lint-free cloth dampened with anhydrous ethanol to wipe the inner surface of the free toroidal mold to remove dust, oil and other impurities, and to prevent pitting and scratches from appearing on the lens surface after molding. S2. Blank preparation: The cut resin blank is ultrasonically cleaned, dried and placed in the center of the mold, ensuring that the deviation between the blank and the positioning reference of the mold is ≤±2μm. S3. Mold closing: Close the lower mold and upper mold that hold the blank, place them into the cavity of the vacuum adsorption equipment, and lock the mold clamps. S4. Heating and softening: Heating rate: 5℃ / min; Holding temperature: Softening point of substrate ±5℃; Holding time 20~25min. Segmented heating is adopted (room temperature → 80℃ → softening point) to avoid stress inside the blank. The substrate will soften when the softening point temperature is reached, and the resin substrate will exhibit high ductility. At this time, plastic deformation can occur under the action of external force. S5. Vacuuming: Vacuum degree: ≤1Pa; Holding time: 15~30min; Hold pressure for 30min, activate real-time pressure compensation to ensure complete fit in complex curved areas (such as edge transition areas). Use a vacuum pump to extract air between the mold and the blank to form a vacuum environment of ≤1Pa. Utilize the pressure difference between the external atmospheric pressure and the internal negative pressure to tightly press the softened blank onto the mold surface. S6. Cooling and curing: Cooling rate: 3℃ / min; Cooling endpoint: room temperature; Gradient cooling (softening point → 100℃ → 50℃ → room temperature) is used to eliminate internal stress in the resin and prevent surface springback; The inner wall of the mold is a pre-processed free toroidal surface profile. The blank completely fits the mold under pressure. After cooling and curing, a complex surface consistent with the design can be formed. Compared with traditional CNC turning, it can better ensure the continuity and consistency of the surface. S7. Mold opening and part removal: After the mold temperature drops to room temperature, open the fixture and remove the formed lens blank. Check the surface for defects such as poor adhesion and bubbles. S8. Edge trimming: Remove excess material and positioning edges from the blank to obtain a preliminary free-form torus lens shape; S9. Stress testing: Use a polarizer to test the internal stress of the lens. Defective products need to be annealed again or scrapped. S10. Lens surface strengthening and coating: Apply a hardening coating to the lens surface using a UV hardening machine. Thickness: 3-5 μm, curing time: 30-60 s, coating hardness: ≥4H; Vacuum evaporation: 15-25 layers.

[0020] The resin material can be high-end substrates such as polyurethane (MR-17) and high oxygen permeability (PC), with a softening temperature of 120-180℃. In step S4, the heating and softening temperature is controlled within ±2℃ of the substrate softening point. If the temperature is too high, the resin will decompose and turn yellow. If the temperature is too low, the blank will not soften sufficiently and will not be able to fit the mold.

[0021] The vacuum evaporation coating has 20 layers, and an anti-reflective coating can be deposited on the lens surface: through the interference effect of the multilayer film, the reflectivity of the lens is reduced from 8% to 10% to below 1%, and the light transmittance is increased to more than 98%, thus reducing glare; Hydrophobic and oleophobic coating: The top layer is coated with a fluoride coating to enhance the lens's ability to resist water and oil stains and make it easy to clean; Functional films: Depending on the requirements, anti-blue light film (blocks 380-450nm blue light), anti-ultraviolet film (blocks UVA / UVB), color-changing film (changes color when exposed to light), etc. can be added.

[0022] The manufacturing process of the 6-degree free-form toroidal lens of this invention is based on accurate optometry, with digital modeling as the core. It achieves precise replication of the design through vacuum forming, combined with surface strengthening and strict quality control, and finally produces a high-quality lens that combines high-definition imaging, wide field of vision and thin appearance.

[0023] The foregoing description illustrates and describes several preferred embodiments of the present invention. However, as previously stated, it should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the inventive concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A manufacturing process for a 6-degree free-form torus lens, characterized in that, The specific steps include: S1. Mold cleaning: Use a lint-free cloth dampened with anhydrous ethanol to wipe the inner surface of the free toroidal mold to remove dust, oil and other impurities, and to prevent pitting and scratches from appearing on the lens surface after molding. S2. Blank preparation: The cut resin blank is ultrasonically cleaned, dried and placed in the center of the mold to ensure that the blank is aligned with the positioning reference of the mold. S3. Mold closing: Close the lower mold and upper mold that hold the blank, place them into the cavity of the vacuum adsorption equipment, and lock the mold clamps. S4. Heating and softening: Heating rate: 5℃ / min; Holding temperature: 5℃ ± the softening point of the substrate; Holding time: 20~25min, using segmented heating (room temperature → 80℃ → softening point) to avoid stress inside the blank. S5. Vacuuming: Vacuum degree: ≤1Pa; Pressure holding time: 15~30min; Hold pressure for 30min, then activate real-time pressure compensation to ensure complete fit in complex curved areas (such as edge transition areas); S6. Cooling and curing: Cooling rate: 3℃ / min; Cooling endpoint: room temperature; Gradual cooling (softening point → 100℃ → 50℃ → room temperature) is used to eliminate internal stress in the resin and prevent surface springback. S7. Mold opening and part removal: After the mold temperature drops to room temperature, open the fixture and remove the formed lens blank. Check the surface for defects such as poor adhesion and bubbles. S8. Edge trimming: Remove excess material and positioning edges from the blank to obtain a preliminary free-form torus lens shape; S9. Stress testing: Use a polarizer to test the internal stress of the lens. Defective products need to be annealed again or scrapped. S10. Lens surface strengthening and coating: Apply a hardening coating to the lens surface using a UV hardening machine. Thickness: 3-5 μm, curing time: 30-60 s, coating hardness: ≥4H; Vacuum evaporation: 15-25 layers.

2. The manufacturing process of the 6-degree free-form torus lens as described in claim 1, characterized in that, In step S2, the deviation between the positioning reference of the blank and the mold is ≤ ±2μm.

3. The manufacturing process of the 6-degree free-form torus lens as described in claim 2, characterized in that, The resin material is polyurethane, and its softening temperature is 120-180℃.

4. The manufacturing process of the 6-degree free-form torus lens as described in claim 3, characterized in that, In step S4, the heating and softening temperature is controlled at ±2℃ of the substrate softening point.

5. The manufacturing process of the 6-degree free-form torus lens as described in claim 4, characterized in that, The vacuum-deposited film consists of 20 layers, distributed on the front and back surfaces of the lens.