A method of manufacturing a contact lens

Abstract

The application discloses a kind of manufacturing methods of contact lenses, it is related to contact lens production technical field, comprising the following steps: raw material pretreatment, select biocompatibility oxygen permeable material as base raw material;Mold pretreatment, preparation upper and lower laminating mold, mold is carried out plasma cleaning, static electricity is handled, then spray release agent and dry;Precise injection and laminating, raw material mixed solution is accurately injected into lower mold, upper and lower mold are accurately aligned and laminated;Gradient solidification forming, using the composite process of ultraviolet pre-curing and heat curing, gradient solidification is carried out to laminated mold;Demoulding and trimming, through laser trimming, the burr of lens edge is removed;Hydration and post-processing, lens is placed in sterile normal saline and hydrated;Detection and sorting, optical performance and relevant index detection are carried out to finished product lens.The present application provides a kind of manufacturing method, which can consider precision, efficiency, cost and compatibility, realize the scale production of multiple types of contact lenses.

Description

Technical Field

[0001] This invention relates to the field of contact lens manufacturing technology, and more particularly to a method for manufacturing contact lenses. Background Technology

[0002] Contact lenses, as vision correction or aesthetic devices that are directly attached to the surface of the cornea of ​​the eye, have extremely high requirements for precision, biocompatibility, and wearing comfort in their manufacturing process. Currently, existing contact lens manufacturing methods mainly include turning, centrifugal casting, and the emerging 3D printing method, but all of them have significant drawbacks.

[0003] Turning, which involves carving and polishing from block materials to form lenses, allows for personalized customization but has extremely low production efficiency. Furthermore, the surface finish of the lenses is easily affected by processing precision, making it difficult to meet the demands of large-scale production. Additionally, it easily leads to material waste during processing. Centrifugal casting, which uses a rotating mold to solidify a monomer solution, can improve lens forming efficiency, but the monomer distribution during forming is easily affected by centrifugal speed, resulting in unstable optical performance. It also struggles to adapt to the precise pattern printing required for colored contact lenses and the integration of functional layers into smart contact lenses. While 3D printing technology offers customization advantages and can manufacture complex microstructures, current technology has limited resolution, making it difficult to achieve the microscale features required for contact lenses (such as microchannels below 100μm). Moreover, the biocompatibility and oxygen permeability of the printing materials are insufficient for long-term wear, and the equipment costs are high, making it unsuitable for large-scale mass production.

[0004] Therefore, developing a manufacturing method that can balance accuracy, efficiency, cost, and compatibility to achieve large-scale production of various types of contact lenses has become an urgent technical problem to be solved in the current contact lens manufacturing field. Summary of the Invention

[0005] The purpose of this invention is to address the deficiencies in the existing technology by proposing a method for manufacturing contact lenses.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A method for manufacturing a contact lens includes the following steps: S1. Raw material pretreatment: Select biocompatible oxygen-permeable material as the base raw material, add moisturizer, antibacterial agent and molding aid, stir evenly under vacuum to form raw material mixture; for colored contact lenses, add medical grade pigment and stir simultaneously. S2. Mold pretreatment: Prepare upper and lower bonding molds, perform plasma cleaning and static electricity removal treatment on the molds, then spray release agent and let them dry; for colored contact lenses, transfer the pattern to the lower mold using a pad printing device and dry it, while cleaning the residual color and static electricity from the pad printing head. S3. Precise injection and bonding: The raw material mixture is precisely injected into the lower mold, and then the upper and lower molds are precisely aligned and bonded to ensure a good seal; S4. Gradient curing molding: A composite process of UV pre-curing and thermal curing is used to perform gradient curing on the bonded mold, and the curing parameters are monitored and dynamically adjusted in real time. S5. Demolding and trimming: The molded lens is removed by vacuum adsorption, and the edges of the lens are trimmed by laser to remove burrs and perform preliminary cleaning; S6. Hydration and post-processing: The lenses are hydrated in sterile saline solution, followed by ultrasonic cleaning, sterilization, and drying to obtain the finished contact lenses; S7. Inspection and sorting: Conduct optical performance and related index tests on finished lenses, sort and package qualified lenses, and recycle and dispose of unqualified lenses.

[0007] Furthermore, in step S1, the substrate material is silicone hydrogel or fluorosilicone acrylate; the vacuum stirring temperature is 25-35℃, the vacuum degree is -0.08~-0.06MPa, and the stirring time is 30-60min.

[0008] Furthermore, in step S2, the mold is made of quartz glass or medical-grade resin, and the mating surfaces of the upper and lower molds are provided with positioning grooves and sealing edges; the power of plasma cleaning is 100-150W, and the cleaning time is 10-15min; the thickness of the release agent is 5-10μm.

[0009] Furthermore, in step S3, the injection error of the raw material mixture does not exceed ±0.001mm; the bonding pressure is 0.1-0.3MPa, and the bonding time is 5-10s.

[0010] Furthermore, in step S4, the wavelength of ultraviolet pre-curing is 280-320nm, the light intensity is 50-80mW / cm², and the pre-curing time is 10-15min; the thermal curing adopts gradient heating, from 25℃ to 60-70℃, the heating rate is 5℃ / min, and the heat preservation curing time is 20-30min.

[0011] Furthermore, in step S5, the negative pressure of vacuum demolding is 0.05-0.07MPa; the precision of laser trimming does not exceed ±0.002mm.

[0012] Furthermore, in step S6, the hydration temperature is 30-35℃, the hydration time is 2-4 hours; the ultrasonic cleaning power is 80-100W, the cleaning time is 5-10 minutes; the sterilization method is high-pressure steam sterilization or ultraviolet sterilization, the sterilization time is 15-20 minutes; the drying temperature is 40-50℃, the drying time is 30-40 minutes.

[0013] Beneficial effects

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: By employing precise liquid injection, mold positioning and bonding, and gradient curing processes, combined with laser trimming technology, the lens thickness error is controlled within ±0.001mm, and the trimming accuracy is controlled within ±0.002mm. This effectively solves problems such as lens curvature deviation, edge burrs, and unstable optical performance in existing technologies. At the same time, plasma cleaning and static electricity removal treatment avoid the influence of impurities and static electricity on the mold surface on the molding effect, improving the surface smoothness and optical clarity of the lens, and ensuring precise control of color difference in colored lenses. By selecting biocompatible silicone hydrogel and fluorosilicone acrylate as the base materials, and adding medical-grade moisturizers and antibacterial agents, combined with thorough hydration treatment, the lenses are made soft, comfortable, and highly oxygen-permeable. Long-term wear is less likely to cause dryness or foreign body sensation, and they also have a certain antibacterial effect, reducing the risk of eye infections. Attached Figure Description

[0015] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0016] Figure 1 This is a flowchart of a method for manufacturing contact lenses. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0018] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0019] Reference Figure 1 , A method for manufacturing a contact lens includes the following steps: S1. Raw material pretreatment: Biocompatible oxygen-permeable materials are selected as the base material, including silicone hydrogel or fluorosilicone acrylate. Moisturizers, antibacterial agents and molding aids are added and placed in a vacuum stirring device. The mixture is stirred for 30-60 minutes at a temperature of 25-35℃ and a vacuum degree of -0.08~-0.06MPa to form a uniform raw material mixture. For colored contact lenses, medical-grade pigments are added and stirred and mixed synchronously with the base material to ensure uniform pigment dispersion and avoid color difference.

[0020] S2. Mold Pretreatment: Quartz glass or medical-grade resin is used to prepare upper and lower bonding molds. The upper mold has a convex structure, and the lower mold has a concave structure. Both the upper and lower mold bonding surfaces are machined with micro-scale positioning grooves and sealing edges to ensure bonding accuracy. The mold is placed in a plasma cleaner and surface-cleaned at a plasma power of 100-150W for 10-15 minutes to remove impurities and static electricity. Then, a layer of release agent is evenly sprayed onto the bonding surfaces of the mold, with a thickness controlled at 5-10μm. After drying, it is ready for use. For colored contact lens production, a pre-set pattern is precisely transferred to the concave surface of the lower mold using a pad printing device. After transfer printing, it is quickly dried using a drying transition device to ensure firm pigment adhesion. Simultaneously, a static eliminator is used to clean residual pigment from the pad printing head to avoid color differences and impurities.

[0021] S3. Precise Injection and Bonding: The pre-treated raw material mixture is injected into the concave surface of the lower mold through a high-precision injection device. The injection volume is precisely controlled according to the preset thickness of the contact lens, with an error of no more than ±0.001mm. Then, the upper and lower molds are precisely aligned through the positioning groove and bonded using a hydraulic bonding device. The bonding pressure is controlled at 0.1-0.3MPa, and the bonding time is 5-10s to ensure good mold sealing and avoid raw material leakage and air bubble generation.

[0022] S4. Gradient Curing and Molding: The bonded mold is sent into a gradient curing device and cured using a composite process of "UV pre-curing + thermal curing". First, UV pre-curing is performed with a UV wavelength of 280-320nm, a light intensity of 50-80mW / cm², and a pre-curing time of 10-15min, allowing the raw material mixture to initially take shape. Then, thermal curing is performed using a gradient heating method, gradually increasing the temperature from 25℃ to 60-70℃ at a heating rate of 5℃ / min, and holding the temperature for 20-30min to ensure that the raw materials are fully polymerized, improving the lens molding strength and oxygen permeability. During the curing process, the internal temperature and pressure of the mold are monitored in real time, and the curing parameters are dynamically adjusted according to the monitoring data to avoid shrinkage, deformation, or cracking of the lens.

[0023] S5. Demolding and Trimming: After curing, the mold is sent to the demolding device, and the molded lens is smoothly removed under a negative pressure of 0.05-0.07MPa using a vacuum suction cup adsorption method to avoid scratching the lens surface. Then, the lens is sent to a high-precision trimming device, and the edge of the lens is trimmed by laser trimming technology. The trimming accuracy is controlled within ±0.002mm to remove edge burrs and excess material, making the edge of the lens smooth and rounded, conforming to the curvature of the eyeball. After trimming, the lens is initially cleaned to remove residual mold release agent and impurities from the surface.

[0024] S6. Hydration and Post-treatment: Place the trimmed lenses in a constant temperature and humidity hydration chamber, add sterile saline, maintain a hydration temperature of 30-35℃, and hydrate for 2-4 hours to allow the lenses to fully absorb water and soften, improving wearing comfort. After hydration, perform ultrasonic cleaning on the lenses at a power of 80-100W for 5-10 minutes to remove residual impurities and unpolymerized monomers from inside the lenses. Subsequently, sterilize the lenses using high-pressure steam sterilization or ultraviolet sterilization for 15-20 minutes to ensure sterility. Finally, dry the lenses at a temperature of 40-50℃ for 30-40 minutes to obtain the finished contact lenses.

[0025] S7. Inspection and Sorting: The finished contact lenses are inspected using optical inspection equipment. The inspection items include lens thickness, curvature, oxygen permeability, optical clarity, surface smoothness, and the effectiveness of color difference and pattern integrity of colored lenses. Lenses that pass the inspection are sorted and packaged, and unqualified lenses are recycled to achieve material recycling and reduce waste.

[0026] In other preferred embodiments, the equipment used in step S1 includes a vacuum stirring device, a raw material storage tank, and a raw material delivery pump. The vacuum stirring device is used to stir and mix the base raw material, additives, and pigments (if necessary) to form a uniform raw material mixture. The raw material storage tank is used to store the pretreated raw material mixture. The raw material delivery pump is used to accurately deliver the raw material mixture to the liquid injection bonding module. The vacuum stirring device is equipped with a temperature and vacuum degree monitoring unit to provide real-time feedback on the stirring parameters and ensure that the raw materials are mixed uniformly.

[0027] In step S2, the equipment used includes a mold preparation device, a plasma cleaner, a release agent spraying device, a pad printing device, a drying transition device, and an antistatic device. The mold preparation device is used to process and prepare upper and lower bonding molds. The plasma cleaner is used to clean the surface of the mold and remove static electricity. The release agent spraying device is used to uniformly spray the release agent on the surface of the mold. The pad printing device is used for pattern pad printing of colored contact lenses. It is equipped with multiple sets of pad printing pads and patterned steel plates, which can realize simultaneous pad printing of multiple molds. The drying transition device is used for rapid drying of the pigment after pad printing. The antistatic device is used to clean the residual pigment and static electricity from the pad printing pads to avoid color difference and impurity residue. The mold processing module is also equipped with a mold positioning and calibration unit to ensure the mold processing accuracy and bonding accuracy.

[0028] In step S3, the equipment used includes a high-precision liquid injection device, a hydraulic fitting device, and a mold positioning device. The high-precision liquid injection device is equipped with a flow adjustment unit, which can accurately control the liquid injection volume according to the lens specifications, with an error of no more than ±0.001mm. The hydraulic fitting device is used for the precise fitting of the upper and lower molds, and the fitting pressure and time can be adjusted. The mold positioning device is used for the precise alignment of the upper and lower molds to ensure the fitting accuracy and avoid material leakage and air bubble generation.

[0029] In step S4, the equipment used includes a gradient curing chamber, a temperature sensor, a pressure sensor, and a parameter adjustment unit. The gradient curing chamber is equipped with an ultraviolet light irradiation component and a heating component, which can realize the "ultraviolet pre-curing + thermal curing" composite process. The temperature sensor and pressure sensor monitor the temperature and pressure data in real time during the curing process and transmit the data to the central control module. The parameter adjustment unit dynamically adjusts the ultraviolet light intensity, heating rate, and holding time according to the instructions of the central control module to ensure that the lens is fully cured and avoid deformation and cracks.

[0030] In step S5, the equipment used includes a vacuum demolding device, a laser trimming device, and a preliminary cleaning device. The vacuum demolding device uses a vacuum suction cup to smoothly remove the molded lens and avoid surface scratches. The laser trimming device is used for high-precision trimming of the lens edge, with trimming accuracy controlled within ±0.002mm. The preliminary cleaning device is used to remove residual demolding agent and impurities from the lens surface to prepare for subsequent hydration treatment.

[0031] In step S6, the equipment used includes a constant temperature and humidity hydration chamber, an ultrasonic cleaning device, a sterilization device, and a drying device. The constant temperature and humidity hydration chamber is used for the full hydration of the lens, and the hydration temperature and time can be adjusted. The ultrasonic cleaning device is used to remove residual impurities and unpolymerized monomers from inside the lens. The sterilization device uses high-pressure steam or ultraviolet sterilization to ensure that the lens is sterile. The drying device is used for drying the lens, controlling the drying temperature and time to prevent lens deformation.

[0032] In step S7, the equipment used includes an optical inspection device, a defective product recycling device, and a qualified product sorting and packaging device. The optical inspection device is used to inspect various indicators such as the thickness, curvature, oxygen permeability, and optical clarity of the finished lenses, as well as the color difference, pattern integrity, and functional layer effectiveness of colored lenses and smart lenses. The defective product recycling device is used to recycle defective lenses for material recycling. The qualified product sorting and packaging device is used to sort and package qualified lenses to achieve automated packaging.

[0033] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for manufacturing a contact lens, characterized in that, Includes the following steps: S1. Raw material pretreatment: Select biocompatible oxygen-permeable material as the base raw material, add moisturizer, antibacterial agent and molding aid, stir evenly under vacuum to form raw material mixture; for colored contact lenses, add medical grade pigment and stir simultaneously. S2. Mold pretreatment: Prepare upper and lower bonding molds, perform plasma cleaning and static electricity removal treatment on the molds, then spray release agent and let them dry; for colored contact lenses, transfer the pattern to the lower mold using a pad printing device and dry it, while cleaning the residual color and static electricity from the pad printing head. S3. Precise injection and bonding: The raw material mixture is precisely injected into the lower mold, and then the upper and lower molds are precisely aligned and bonded to ensure a good seal; S4. Gradient curing molding: A composite process of UV pre-curing and thermal curing is used to perform gradient curing on the bonded mold, and the curing parameters are monitored and dynamically adjusted in real time. S5. Demolding and trimming: The molded lens is removed by vacuum adsorption, and the edges of the lens are trimmed by laser to remove burrs and perform preliminary cleaning; S6. Hydration and post-processing: The lenses are hydrated in sterile saline solution, followed by ultrasonic cleaning, sterilization, and drying to obtain the finished contact lenses; S7. Inspection and sorting: Conduct optical performance and related index tests on finished lenses, sort and package qualified lenses, and recycle and dispose of unqualified lenses.

2. The method for manufacturing a contact lens according to claim 1, characterized in that: In step S1, the substrate material is silicone hydrogel or fluorosilicone acrylate; the vacuum stirring temperature is 25-35℃, the vacuum degree is -0.08~-0.06MPa, and the stirring time is 30-60min.

3. The method for manufacturing a contact lens according to claim 1, characterized in that: In step S2, the mold is made of quartz glass or medical-grade resin, and the mating surfaces of the upper and lower molds are provided with positioning grooves and sealing edges; the power of plasma cleaning is 100-150W, and the cleaning time is 10-15min; the thickness of the release agent is 5-10μm.

4. The method for manufacturing a contact lens according to claim 1, characterized in that: In step S3, the injection error of the raw material mixture shall not exceed ±0.001 mm; the bonding pressure shall be 0.1-0.3 MPa; and the bonding time shall be 5-10 s.

5. The method for manufacturing a contact lens according to claim 1, characterized in that: In step S4, the wavelength of UV pre-curing is 280-320nm, the light intensity is 50-80mW / cm², and the pre-curing time is 10-15min; the heat curing adopts gradient temperature increase, from 25℃ to 60-70℃, the temperature increase rate is 5℃ / min, and the heat preservation curing time is 20-30min.

6. The method for manufacturing a contact lens according to claim 1, characterized in that: In step S5, the negative pressure for vacuum demolding is 0.05-0.07 MPa; the precision of laser trimming does not exceed ±0.002 mm.

7. The method for manufacturing a contact lens according to claim 1, characterized in that: In step S6, the hydration temperature is 30-35℃ and the hydration time is 2-4 hours; the ultrasonic cleaning power is 80-100W and the cleaning time is 5-10 minutes; the sterilization method is high-pressure steam sterilization or ultraviolet sterilization and the sterilization time is 15-20 minutes; the drying temperature is 40-50℃ and the drying time is 30-40 minutes.

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