A physical oxygen permeability enhanced contact lens mold structure and full mold molding method
Patent Information
- Application Number
- CN202611293963.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-08-25
- Publication Date
- 2026-10-16
AI Technical Summary
由此成型的镜片，其光学区外围的过渡区整体偏厚，导致氧气扩散路径较长，同时还会阻碍周边泪液的循环交换
模具材质优越：模仁采用铍铜材质，具备高硬度、高导热、易超精密车削、表面光洁度高的优势，特别适合隐形眼镜微结构模具的长期精密复刻使用。
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Figure CN122914565A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of contact lens manufacturing technology, and more specifically, to a contact lens core structure for physically improving oxygen permeability and a full compression molding method based on the core structure. Background Technology
[0002] During contact lens wear, the normal metabolism of the cornea depends on a sufficient supply of oxygen. Oxygen reaches the cornea mainly through two pathways: one is through the oxygen permeability of the lens material itself, and the other is through exchange between the peripheral area of the lens and the tear film circulation in the eye.
[0003] Currently, the mainstream technical approaches to improving the oxygen permeability of contact lenses fall into two categories: The first approach is chemical modification, such as developing highly oxygen-permeable materials like silicone hydrogels. However, this approach has significant drawbacks, including complex formulation design, high raw material costs, long biocompatibility verification cycles, and high barriers to mass production processes.
[0004] The second type is the physical structural approach, such as creating through-holes in the lens body to allow for ventilation. However, this method severely compromises the optical integrity and structural strength of the lens, making it prone to stress cracking and difficult to adapt to the large-scale production requirements of traditional full-molding unibody processes.
[0005] Existing conventional fully molded contact lens molds are designed only for the basic curved surface of the mold core, without any specific microstructural optimization for oxygen permeability. Lenses formed in this way have a generally thicker transition zone around the optical zone, resulting in a longer oxygen diffusion path and hindering the circulation and exchange of surrounding tears. Long-term wear of such lenses can easily cause clinical problems such as corneal hypoxia, dry eyes, and discomfort.
[0006] Therefore, there is an urgent need in this field to develop a high oxygen permeability contact lens solution that does not require changes to the chemical formulation of the lens material, relies on physical optimization of the mold microstructure, and can be adapted to existing full-molding mass production lines. Summary of the Invention
[0007] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a contact lens mold core structure and a full molding method that physically improves oxygen permeability. This solution involves arranging a cross-shaped microlens array of specific shape and size in the transition zone of the mold core. After molding and replication, the transition zone of the lens is locally thinned, and the surface micromorphology is optimized. This physically improves oxygen permeability without changing the original lens material formulation and is well-compatible with existing full molding production lines.
[0008] To achieve the above objectives, the present invention provides the following technical solution: A contact lens core structure that physically enhances oxygen permeability, comprising a metal core; The surface of the mold core body is divided into a central optical zone, a transition zone, and an edge zone; The transition region surface is processed with multiple microlenses, which are cross-shaped microlenses with a depth of 0.005 mm to 0.03 mm and are uniformly distributed in a ring. The cross-shaped microlens has a cross-shaped cross section.
[0009] Preferably, the transition zone is an annular area 0.5mm to 1.5mm outside the optical zone of the corresponding contact lens, and the microlens is only disposed in the transition zone and does not cover the central optical zone and the edge zone.
[0010] Preferably, the metal core is made of beryllium copper.
[0011] Preferably, the number of cross-shaped microlenses is 420, the circumscribed circle diameter of a single cross-shaped microlens is 0.1 mm to 0.3 mm, and the center-to-center distance between adjacent cross-shaped microlenses is 0.15 mm to 0.35 mm.
[0012] Preferably, in the cross-shaped cross section of the cross-shaped microlens, the width of both the transverse and longitudinal arms is 0.02 mm to 0.05 mm, and the arm length is 0.05 mm to 0.15 mm.
[0013] Preferably, the plurality of cross-shaped microlenses are machined using an ultra-precision single-crystal diamond lathe, with a surface roughness Ra≤0.02μm.
[0014] A method for full compression molding of a mold core structure includes the following steps: S1: Provide the metal mold core and process the cross-shaped microlens array in its transition region; S2: Using the finished metal mold core as the master mold, the upper and lower molds are prepared by precision injection molding to obtain a contact lens mold with a microstructure replication surface; S3: Inject the hydrogel or silicone hydrogel material into the mold cavity formed by the upper and lower molds; S4: Perform full molding and curing to obtain the molded lens; S5: Perform post-processing on the molded lens to obtain the finished contact lens.
[0015] Preferably, in step S2, the process conditions for precision injection molding are: temperature 200°C to 250°C and pressure 80MPa to 120MPa.
[0016] Preferably, in step S4, the process conditions for full molding and curing are: temperature 120°C to 150°C, pressure 5MPa to 15MPa, and curing time 10 minutes to 30 minutes; and the coaxiality of the upper mold and the lower mold is ≤0.002mm.
[0017] Compared with the prior art, the beneficial technical effects of the present invention are as follows: Superior mold material: The mold core is made of beryllium copper, which has the advantages of high hardness, high thermal conductivity, easy ultra-precision machining, and high surface finish. It is especially suitable for long-term precision replication of microstructure molds for contact lenses.
[0018] Physical oxygen permeability enhancement without material modification: By molding and replicating the cross-shaped microlens array in the transition zone, the transition zone of the lens is physically thinned, effectively shortening the oxygen diffusion path and increasing the tear film contact exchange area. Without changing the chemical formula of the lens material, the oxygen permeability can be physically improved by 15% to 30%.
[0019] Suitable for mass production: The mold core structure, combined with precision injection molding and full compression molding processes, can achieve simultaneous molding of multiple cavities, resulting in a high yield rate. It is seamlessly compatible with existing full compression molding production lines and is suitable for large-scale industrial production.
[0020] It does not affect optical performance or wearing comfort: the microstructure is only set in the transition area and does not cover the central optical area, so it does not affect the refractive correction effect of the lens at all; at the same time, it does not change the structure of the edge area, so the wearing fit and comfort are not affected.
[0021] Parameters are controllable and products are highly adaptable: the number, depth, and distribution parameters of microlenses can be flexibly adjusted according to different lens specifications, and can be adapted to various types of products such as daily disposables, monthly disposables, and astigmatism lenses. Attached Figure Description
[0022] The present invention will be further described below with reference to the accompanying drawings.
[0023] Figure 1 This is a three-dimensional schematic diagram of the contact lens core structure described in this invention; Figure 2 This is a magnified schematic diagram of a cross-shaped microlens. Figure 3 This is a schematic diagram of the cross-sectional structure of the formed contact lens.
[0024] Explanation of reference numerals in the attached diagram: 1. Central optical zone; 2. Transition zone; 3. Edge zone. Detailed Implementation
[0025] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.
[0026] Example 1: Mold Core Structure Design and Machining
[0027] Beryllium copper alloy (grade: BeCu-275) is selected as the base material for the mold core and is integrally machined.
[0028] like Figure 1-3 As shown, the surface of the mold core is divided into three regions: Central optical zone 1: Diameter 6.0mm; Transition zone 2: Located outside the optical zone, corresponding to a ring area with a width of 3.0mm (i.e., extending outward from the outer edge of the optical zone by 0.5mm to 3.5mm). Edge zone 3: The outer edge of the transition zone to the lens edge; like Figure 2 As shown, an array of 420 cross-shaped microlenses is fabricated on the surface of the transition region. The fabrication parameters are as follows: Microlens depth: 0.015mm~0.03mm (gradually increasing from the inside out); The diameter of the circumcircle of a single microlens is 0.1 mm. The center-to-center distance between adjacent microlenses is 0.4 mm. Cross-shaped cross-section arm width: 0.02mm, arm length: 0.1mm; The processing equipment used was an ultra-precision single-crystal diamond lathe (model: Nanoform 700 Ultra), and the measured surface roughness after processing was Ra=0.015μm. After processing, ultrasonic cleaning and deburring and polishing were performed.
[0029] Example 2: Full Compression Molding Process and Product Inspection
[0030] The beryllium copper mold core prepared in Example 1 was used as the master mold, and the upper and lower molds were prepared by precision injection molding. Injection molding process conditions: temperature 230℃, pressure 100MPa.
[0031] A hydrogel material (etafilcon A) with a water content of 55% was precisely injected into the mold cavity formed by the upper and lower molds, with the injection amount error controlled within ±0.01g. After mold closing, full compression molding was performed: temperature 130℃, pressure 10MPa, curing time 20 minutes. During the mold closing process, the coaxiality of the upper and lower molds was controlled to be 0.0015mm.
[0032] After curing, the molded lenses are demolded, then hydrated (soaked in deionized water for 6 hours), cleaned, disinfected, and packaged to obtain finished contact lenses.
[0033] The contact lens core structure and full molding method provided by this invention can be widely applied to the large-scale industrial production of various types of contact lenses, such as daily disposables, monthly disposables, astigmatic lenses, and multifocal lenses, and has good industrial applicability and economic value.
[0034] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.
[0035] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.
Claims
1. A contact lens core structure that physically enhances oxygen permeability, characterized in that: Including metal mold cores; The surface of the metal mold core is divided into a central optical zone, a transition zone, and an edge zone; The transition region surface is processed with multiple microlenses, which are cross-shaped microlenses with a depth of 0.005 mm to 0.03 mm and are uniformly distributed in a ring. The cross-shaped microlens has a cross-shaped cross section.
2. The contact lens core structure for physically enhancing oxygen permeability according to claim 1, characterized in that: The transition zone is a ring-shaped area 0.5mm to 1.5mm outside the optical zone of the corresponding contact lens. The microlens is only arranged in the transition zone and does not cover the central optical zone or the edge zone.
3. The contact lens core structure for physically enhancing oxygen permeability according to claim 1, characterized in that: The metal core is made of beryllium copper.
4. The contact lens core structure for physically enhancing oxygen permeability according to claim 1, characterized in that: The number of cross-shaped microlenses is 420, the circumscribed circle diameter of a single cross-shaped microlens is 0.1 mm to 0.3 mm, and the center-to-center distance between adjacent cross-shaped microlenses is 0.15 mm to 0.35 mm.
5. The contact lens core structure for physically enhancing oxygen permeability according to claim 1, characterized in that: In the cross-shaped cross section of the cross-shaped microlens, the width of both the horizontal and vertical arms is 0.02 mm to 0.05 mm, and the arm length is 0.05 mm to 0.15 mm.
6. The contact lens core structure for physically enhancing oxygen permeability according to claim 1, characterized in that: The multiple cross-shaped microlenses are machined using an ultra-precision single-crystal diamond lathe, with a surface roughness Ra≤0.02μm.
7. A full compression molding method based on the mold core structure described in any one of claims 1 to 6, characterized in that, Includes the following steps: S1: Provide the metal mold core and process the cross-shaped microlens array in its transition region; S2: Using the finished metal mold core as the master mold, the upper and lower molds are prepared by precision injection molding to obtain a contact lens mold with a microstructure replication surface; S3: Inject the hydrogel or silicone hydrogel material into the mold cavity formed by the upper and lower molds; S4: Perform full molding and curing to obtain the molded lens; S5: Perform post-processing on the molded lens to obtain the finished contact lens.
8. The full compression molding method for the mold core structure according to claim 7, characterized in that, In step S2, the process conditions for precision injection molding are: temperature 200℃ to 250℃ and pressure 80MPa to 120MPa.
9. The full compression molding method for the mold core structure according to claim 7, characterized in that, In step S4, the process conditions for full molding and curing are: temperature 120℃ to 150℃, pressure 5MPa to 15MPa, and curing time 10 minutes to 30 minutes; and the coaxiality of the upper mold and the lower mold is ≤0.002mm.