Polymer addition manufacturing and ophthalmic lenses formed thereby

Abstract

The present invention provides an improved method and apparatus for additive manufacturing of molded articles having surface quality suitable for use as optical elements such as contact lenses. [Solution] The improvement is directed toward repeatedly coating monomers according to an energy transmittance pattern such as a grayscale image. The method includes intermittent pinning of the deposited polymerizable mixture and final curing of the deposited polymerizable mixture. A pattern of multiple defined regions may be produced, each region representing the amount of energy transmittance associated with that region. Each region may have a value of light based on a scale such as 8-bit, 16-bit, 32-bit, 64-bit scale or other scales. In some embodiments, each region may point to the smallest single component of a digital image.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims priority to U.S. Non - Provisional Application No. 17 / 984,103, filed Nov. 9, 2022, which claims the benefit of U.S. Provisional Application No. 63 / 306,472, filed Feb. 3, 2022, and U.S. Provisional Application No. 63 / 356,583, filed Jun. 29, 2022, the entire disclosures of which are incorporated herein by reference.

[0002] Field of the Invention The present invention relates to the field of improved additive manufacturing, and more particularly to methods and apparatus for forming ophthalmic devices by repeatedly applying droplets of a polymeric material representative of an energy transmittance mapping, and to the resulting lenses.

Background Art

[0003] Background of the Invention Conventional additive manufacturing, which involves the application of materials deposited based on a computer - aided design (CAD) model or other three - dimensional (3D) model, is known. In such processes, the 3D model is sliced into layers that are cross - sections of the 3D design. Each cross - section is sequentially deposited to form a shaped article. Sacrificial layers and / or portions of layers may also be applied in the form of additives that are later removed.

[0004] The materials are typically applied by a sintering process, whereby a small amount of the material is melted and placed at positions corresponding to a particular cross - section, resulting in a fusion deposition process. Such techniques include stereolithography and selective laser sintering.

Summary of the Invention

Problems to be Solved by the Invention

[0005] Additive manufacturing can be low-cost and offers greater flexibility in the design of manufactured goods and production volumes. However, goods formed by additive manufacturing often lack the finished quality obtained by other manufacturing techniques, particularly in terms of sufficient surface smoothness.

[0006] Contact lens manufacturing has evolved over the past few decades, from lathe cutting to spin casting, and now to cast molding, which remains the most cost-effective process. Lathe machining of contact lenses typically involves machining one button of lens material at a time until the desired shape is achieved. Such processes require complex lathe equipment and the expertise of specialized operators. Furthermore, they are not efficient for mass production of contact lenses.

[0007] While cast molding is effective for mass production of contact lenses, each lens is formed according to an approximate size and shape, resulting in variations of up to 1 / 8 or 1 / 4 diopter within the same manufacturing batch. This can lead to variations in patient experience. Such variations in patient experience are sometimes referred to as "good contact lens days" and "bad contact lens days."

[0008] Casting ophthalmic lenses is a complex process involving many variables that are difficult to maintain within acceptable parameters, resulting in variability in the final product. These variables may arise from one or more of the following: depositing a curable mixture of polymerizable monomers into the mold cavity; forming the mold cavity through two mold sections; curing the monomer mixture within the cavity; and disassembling the mold assembly to remove the lens. One mold section forms the anterior lens surface, and the other mold section forms the posterior lens surface.

[0009] The cost of cast molding equipment is very high due to the large size of the associated production lines. Furthermore, the manufacturing of optically high-quality metal inlays used to cast lenses, and the subsequent injection molding of plastic molds, requires significant upfront investment, and the associated designs are limited by the symmetry constraints of cast molding technology. Cast molding also generates a large amount of plastic waste, along with harmful associated environmental impacts and additional costs.

[0010] Furthermore, cast molding requires managing a vast number of SKUs, along with associated warehouse management, order picking, and shipping logistics issues, all of which add significant environmental disadvantages and costs to the resulting contact lens products. Moreover, the types of contact lenses manufactured in the lens molding process can only have a limited number of variations in optical power, base curve, and diameter.

[0011] Summary of the Invention Accordingly, the present invention provides an improved method and apparatus for manufacturing molded articles having surface qualities suitable for use as optical elements, such as in contact lenses. The improvements presented herein are directed toward a process involving repeated coating of monomers according to an energy intensity map, such as a grayscale image mapping the intensity of the energy spectrum related to visible light. The improved method includes intermittent pinning and final curing of the coated monomers, resulting in increased design flexibility for hydrogel-based ophthalmic devices, including rotationally asymmetric ophthalmic devices, and reduced manufacturing costs. According to the present invention, the print head may be positioned during deposition at a position not perpendicular to the apex of the receiving surface, and the droplets may be non-spherical when they contact the receiving surface. Improvements also include reduced waste, reduced environmental impact, reduced warehouse overhead, and reduced labor required for the manufacture and storage of ophthalmic lenses.

[0012] The present invention provides that a lens may be formed through two or more components, including an optical zone (sometimes referred to here as "OZ") and a peripheral zone, or edge portion. One or both of the optical zone and the peripheral zone may be formed based on an energy intensity pattern that describes a non-water-containing axial thickness profile.

[0013] In some embodiments, additive manufacturing equipment may be controlled to perform multiple passes of a print head to add polymerizable material to a receiving surface in order to form a lens (or other molded product) according to an axial thickness profile including the lens power in air (P), lens refractive index (n), center thickness (CT), and back surface radius of curvature (RB).

[0014] Some embodiments of the present disclosure may include a method for forming an ophthalmic lens by additive manufacturing, the method comprising the steps of positioning a substrate at a first position relative to an additive manufacturing print head and releasing a pattern of polymerizable mixture droplets from the print head, the pattern of polymerizable mixture droplets corresponding to a portion of the energy transmittance map of the ophthalmic lens to be formed.

[0015] Some modifications include receiving deposited droplets of polymerizable mixture on a receiving surface, wherein the receiving surface includes the substrate and one or both of the previously released polymerizable mixture. Embodiments may also include repositioning the substrate relative to the print head from a first position to a next position (current position plus N). Repositioning may be achieved by moving one or both of the substrate and the print head.

[0016] Furthermore, a variation of this embodiment includes releasing a subsequent pattern (first position plus N) of deposited droplets of the polymerizable mixture corresponding to the next portion of the energy transmittance map of the formed ophthalmic lens. Multiple releases may occur during the passage of the print head over a receiving surface, which may include a substrate.

[0017] Some modifications may include integrating the material from deposited droplets of polymerizable mixture on the receiving surface, and exposing the integrated material to a pinning process that causes partial polymerization of the deposited droplets of polymerizable mixture. Following the passage of the print head, one or more of gravity, surface tension, and minute forces may act on at least a portion of the deposited droplets to smooth the receiving surface, such as by homogenizing the intervening spaces between the deposited droplets.

[0018] In some embodiments, at least a portion of the polymerizable mixture droplets deposited during the current pass may integrate with the polymerizable mixture previously deposited on the receiving surface to form the same volume, which may comprise a single volume of polymerizable mixture on the substrate. Embodiments may also include pinning the deposited droplets to the receiving surface via partial polymerization of the deposited droplets and curing the deposited droplets of polymerizable mixture. Integration of the deposited droplets relieves the requirement that the disclosed process ensures the droplets maintain a specific shape during, during, or after deposition.

[0019] In some embodiments, the pinning step may include exposing the polymerizable mixture droplets to actinic radiation of a first wavelength for a limited time sufficient to cause gelation of the polymerizable mixture droplets but not to cause hardening of the droplets.

[0020] Furthermore, in some embodiments, the curing step may include exposing the polymerizable mixture droplets to chemical radiation of a second wavelength for a sufficient time and intensity to cause polymerization of the polymerizable mixture droplets deposited in one or more cycles of droplet deposition.

[0021] The present invention further provides a method of manufacture that includes a periphery of a formed object and a central portion of the object contained together with the peripheral portion. For example, in some embodiments of the present invention, an ophthalmic contact lens having an overall spherical shape may have an edge portion including an essentially ring shape formed via additive manufacturing (or other manufacturing methods such as machining and / or custom molding), and an optical zone of the contact lens formed within the peripheral portion via an additive manufacturing process. The edge portion preferably has a greater mass than the central portion including the optical zone. During formation, the peripheral ring portion may be partially or fully cured, and internal stresses may be more borne in the portion of greater mass. Forming the edge portion while it is not being acted upon by the central portion allows the edge portion to be formed with reduced stress while the deposited monomer cures to a polymer. The examples provided herein are generally described with reference to spherical contact lenses, but other embodiments such as oval or crescent contact lenses or other shaped intraocular lenses of complex shapes are also within the scope of the present invention.

[0022] In some aspects, the present invention provides for the application of a pattern of a plurality of defined regions contained within a single lens, each region representing the amount of light transmissible through its respective associated region. Each region may have a value of light transmittance based on a scale such as an 8-bit, 16-bit, 32-bit, or 64-bit scale (other scales are also within the scope of the present invention). In some embodiments, each region may refer to the smallest single component of a digital image. Further, in some embodiments, the smallest single component of a digital image may herein be referred to as a "pixel". In some embodiments, a pixel may be associated with a distance measurement such as an amount of nanometers.

[0023] The present invention provides for the subsequent application of a polymerizable material in a plurality of successive patterns, each successive pattern corresponding to a grayscale image. Following the application of each pattern of the grayscale image, the polymerizable material is pinned but not fully polymerized.

[0024] After finally applying the monomers in the pattern of the grayscale image, the monomers aggregated from each application of the grayscale image are polymerized to form a polymer lens, such as a hydrogel contact lens formed from, for example, etafilcon.

[0025] The application of a plurality of successive grayscale image patterns may be deposited one on top of another or may be positioned side by side with each other, and is preferably carried out in a controlled atmosphere. The atmosphere may be controlled to limit a specific amount of variables, such as one or both of the suspended particulate matter and gas present in the atmosphere during a particular process step involved in the manufacturing process, as a non-limiting example. As a specific example, a preferred embodiment includes an atmosphere that limits the amount of oxygen to which the monomers are exposed prior to polymerization, and also limits the size and amount of fine particles that may interact with the monomers prior to polymerization.

[0026] In some embodiments, for some monomers or other polymerizable mixtures, oxygen may be controlled as an important variable involved in the free radical polymerization of the monomer materials and prepolymers involved in the manufacturing process. This may be particularly relevant for ophthalmic devices formed of hydrogels containing a relatively low level of crosslinking agent to be hydrated after polymerization, and whose shape is easily distorted from fluctuations in the resulting polymer network.

[0027] According to another aspect of the present invention, exposure of a monomer or other polymerizable mixture to a gas (such as oxygen) that may affect polymerization properties is carefully controlled in terms of one or more of the exposure amount, the consistency of exposure across the monomer, and the exposure time. It has been found that during polymerization, if the oxygen concentration is higher on one side (side 1) or another part of the monomer forming the optical device compared to a second side (side 2) or other region, side 1 may expand relatively more than side 2, which can cause distortion of the optical properties inherent in the formed optical device. Similarly, parts of a polymerizable mixture with high and low oxygen concentrations may expand by different amounts than other parts with different oxygen concentrations. By limiting the supply of oxygen to the polymerizable mixture before polymerization, a relatively consistent oxygen concentration can be maintained within the polymerizable mixture, thereby achieving a consistent expansion coefficient caused by the oxygen concentration.

[0028] In some embodiments, relatively high concentrations of initiators, high-intensity UV light energy, oxygen scavengers, waxes, or coatings may be used to control the effects of oxygen before polymerization of the polymerizable mixture. However, to date, none of these have been shown to consistently produce high-quality optical devices.

[0029] The present invention takes a novel approach to fabricating optical elements, such as ophthalmic devices, by controlling the presence and concentration of oxygen to low levels and / or simultaneously at a controlled concentration in the use of a 3D printing apparatus. In some embodiments, it is beneficial to control the level of oxygen in the polymerizable mixture relative to the oxygen level in the ambient atmosphere of the polymerizable mixture during the fabrication of the optical device in order to obtain the desired dimensions and resulting optical properties of the optical device contained in the optical element. This principle may be extended to include a substrate on which deposition printing occurs. Accordingly, embodiments include oxygen levels that are maintained at predetermined levels before and during the polymerization process. [Means for solving the problem]

[0030] In a first embodiment, the present invention relates to a method for three-dimensional deposition printing of optical elements, wherein multiple droplets of a polymerizable mixture are deposited on the surface of a substrate under a controlled atmosphere, thereby forming a pattern of energy intensity transmittance through the deposited polymerizable mixture, such as a grayscale, and the controlled atmosphere containing the polymerizable mixture pattern is maintained at an oxygen concentration of at most about 5.0 volume% (preferably at most about 1.0 volume%), and the oxygen equilibrium concentration of the polymerizable mixture is at most about 8.0 volume% (preferably at most about 2.0 volume%). In this context, due to the constraints of measuring the volume percent of the polymerizable mixture and oxygen in the surrounding environment, "about" may be considered to be within 10% of the stated amounts. [Brief explanation of the drawing]

[0031] [Figure 1] Figure 1 shows an exemplary additive manufacturing apparatus that may be used in some embodiments of the present invention. [Figure 2] Figure 2 is a schematic diagram of an alternative 3D printing apparatus according to several embodiments of the present invention. [Figure 3] Figure 3 shows an exemplary energy intensity pattern, represented as a grayscale image, which may be used to generate a control protocol for a 3D printing apparatus according to some embodiments of the present invention. [Figure 4] Figure 4 is a schematic diagram of a spherical lens having a specified peripheral portion according to several embodiments of the present invention. [Figure 5] Figure 5 is a schematic cross-sectional view of the profile of a lens having a peripheral portion and a carrier portion supporting the optical zone, according to several embodiments of the present invention. [Figure 6] Figure 6 shows a graph curve representing an exemplary water-containing surface of an ophthalmic lens that can be formed according to the present invention. [Figure 7] Figure 7 shows a graph curve representing an exemplary non-water-containing axial thickness of an ophthalmic lens that can be molded according to the present invention. [Figure 8] Figure 8 is a schematic diagram of the false-color image in the peripheral region. [Figure 9] Figure 9 is a schematic diagram of a false-color image of a foil lens thickness profile with a transition region zone. [Figure 10] Figure 10 shows a false-color image of the thickness profile of the peripheral zone of an astigmatism lens. [Figure 11] Figure 11 shows a false-color image of the thickness profile of an astigmatism lens. [Figure 12] Figure 12 illustrates method steps that may be performed while carrying out some embodiments of the present invention. [Figure 13] Figure 13 is a schematic diagram of a deposited droplet of polymerizable mixture that integrates with the volume of polymerizable mixture previously deposited on the substrate. [Figure 13A] Figure 13A is a schematic diagram of a deposited droplet of polymerizable mixture that integrates with the volume of polymerizable mixture previously deposited on the substrate. [Figure 14] Figure 14 is a schematic diagram illustrating an example of the change in the shape of polymerizable mixture droplets after discharge from the print head. [Figure 15] Figure 15 shows a flowchart of method steps that may be performed in some embodiments of the present invention. [Figure 15A] Figure 15A shows a flowchart of method steps that may be performed in some embodiments of the present invention. [Modes for carrying out the invention]

[0032] Detailed description of the invention The present invention provides an apparatus and method for coating a surface with small droplets of a polymerizable mixture based on an energy transmittance pattern or map. A grayscale image may be used as a map of visible light energy transmittance. The surface may be a planar surface, an arc-shaped surface, or a complex variable surface. The droplets of polymerizable mixture coated on the surface accumulate to form a pattern of polymerizable mixture that replicates the energy transmittance map. Following coating the surface with the polymerizable mixture, the coated polymerizable mixture may be exposed to a limited amount of chemical radiation (actinic condition), such as radiation (limited in intensity and / or duration) and / or thermal energy. Exposure to a limited amount of chemical radiation is suitable for pinning the coated polymerizable mixture in place.

[0033] The pinned polymerizable mixture may act as a subsequent receiving surface to receive additional polymerizable mixture coated in an energy-transmitting pattern. After the final coating of the polymerizable mixture, the polymerizable mixture accumulated on the substrate surface may be exposed to chemical radiation states (e.g., radiation and thermal energy) sufficient to cure the accumulated polymerizable mixture into a polymer.

[0034] The atmosphere surrounding droplets of the polymerizable mixture during coating onto the receiving surface and during their retention on the receiving surface before curing may be carefully controlled to achieve consistent optical quality in the device formed by the cured polymerizable mixture.

[0035] In this disclosure, ophthalmic lenses (and / or contact lenses) are used for illustrative and discussion purposes, but the principles are applicable to the formation of molded articles in general, and the teachings presented may be broadly applied to any optical element (or other molded article) where precise dimensions, shape, optical properties, and / or similar uniform polymer properties are preferred, such as intraocular lenses.

[0036] According to the present invention, in some embodiments, the polymerizable mixture is delivered at high speed in a gaseous atmosphere having a relatively high surface-to-volume ratio, typically in the form of very small droplets of 1 to 15 picoliters. A large number of droplets (estimated to be 1.5 to 9 million) are required to form a 25-milligram lens. Several factors may be considered to ensure that each droplet is delivered to the appropriate location during manufacturing. These factors include, but are not limited to, one or more of the following: exposure of the droplet to ambient process conditions; the thickness of the material layer resulting when the droplet collides with a surface consisting of one or both of the substrate and the previously deposited polymerizable mixture; interaction with the receiving surface consisting of the substrate and / or the previously deposited polymerizable mixture, such as wetting of the receiving substrate surface and coalescence with the previously deposited polymerizable mixture; the effect of the colliding droplet; pinning of the polymerizable mixture through exposure time to chemical radiation and / or atmospheric gas between the subsequent layers of the droplet; and curing / polymerization of the deposited polymerizable mixture.

[0037] During additive manufacturing processes, polymerizable mixtures are frequently exposed to (and absorbed by) ambient gases such as oxygen from one or more of the surrounding process atmosphere (sometimes called a controlled atmosphere), the receiving substrate surface, and droplets of previously deposited polymerizable mixtures. If these factors are not precisely controlled, the surface and bulk properties (including optical properties) of the resulting ophthalmic lenses will be adversely affected.

[0038] The effects of oxygen are particularly pronounced in lenses manufactured using hydrogel materials such as 2-hydroxyethyl methacrylate (HEMA) or other monomers used in soft contact lenses and soft intraocular lenses. In such materials, variations caused by exposure to oxygen become more pronounced in the final cured lens after the lens has absorbed moisture. Therefore, in preferred embodiments, exposure to oxygen may be considered detrimental.

[0039] Typically, the surface or skin portion of a lens formed in a more oxygen-rich environment contains more polymer network defects than the bulk portion, allowing for greater water absorption in the oxygen-rich areas. The strain that occurs in such skin regions usually negatively impacts the overall mechanical properties (modulus, tensile strength, elongation), optical properties (light transmittance, refractive index, etc.), shape, and inter-part repeatability.

[0040] The present invention teaches how to control and adjust the oxygen content of a polymerizable mixture in relation to the oxygen content of a controlled atmosphere (as described herein), with the aim of controlling the effect of oxygen to such an extent that the properties of the formed optical elements are not significantly affected.

[0041] In these embodiments, including the formation of ophthalmic devices (e.g., contact lenses, intraocular lenses, and spectacle lenses), the ability to create optical formulations largely depends on the precise shape of the curved surfaces. Fabricating these required surfaces on these and other non-ophthalmic optical elements can be achieved by using the principles claimed in this invention, thus enabling the advantages of using 3D deposition printing, such as simplicity, efficiency, greater design freedom, lower time requirements, and cost.

[0042] In some embodiments, the effects of oxygen in the polymerization process and its influence on the properties of the resulting articles are eliminated or substantially reduced. This allows for improved control of the migration of the polymerization mixture after precipitation when forming polymer matrices in layers. This is important in creating curved, arbitrary, or irregular surfaces or shapes, and all the more so when creating complex optical devices that require precise curves, including surfaces incorporating multiple arcuate portions. Therefore, the combined effect of overcoming oxygen inhibition and controlling the migration of polymerizable mixtures in optical product applications is likely to reduce, and even eliminate, optical artifacts and distortions.

[0043] In some embodiments, the present invention provides an apparatus and method for operating the apparatus for three-dimensional deposition manufacturing of ophthalmic devices, in which multiple droplets of a polymerizable mixture are deposited on the surface of a substrate (and / or a previously deposited polymerizable mixture) under a controlled atmosphere, thereby forming layers of the polymerizable mixture into a pattern that replicates an energy transmittance map (such as a grayscale image).

[0044] In some embodiments of the present invention, the oxygen concentration in the polymerizable mixture may be adjusted in relation to one or more of the oxygen concentration in the controlled atmosphere to which the polymerizable mixture is exposed, and the oxygen concentration in other parts of the environment (e.g., a substrate receiving droplets of the polymerizable mixture) so as to avoid or at least suppress oxygen migration from one source to another to an extent that is not important for the polymerization of the polymerizable mixture.

[0045] Glossary

[0046] In this specification and the claims presented toward the present invention, various terms may be used where the following definitions apply.

[0047] As used herein, “chemical radiation” refers to the emission of energy that can initiate a chemical reaction in the relevant polymerizable mixture. In some embodiments, chemical radiation includes radiation having wavelengths in the range of 280–450 nm. In some more specific exemplary embodiments, chemical radiation corresponding to UVA and blue light includes energy having wavelengths in the range of 315–450 nm, and in some preferred embodiments, energy includes energy in the range of 365–400 nm.

[0048] "Addition-based manufacturing" (sometimes referred to as "addition manufacturing" in this specification) means a process in which units of material are added to a structure that is formed into a certain shape through the aggregation of the units of material into a certain shape.

[0049] The term "arc-shaped" as used here refers to a geometric shape that includes a curved surface.

[0050] As used herein, "curing" refers to exposing a polymerizable mixture to a chemical radiation state which may include fixed radiation and / or thermal energy of sufficient intensity to crosslink a large portion of the polymerizable mixture.

[0051] The term "immobilization radiation" as used here refers to chemical radiation of an appropriate wavelength, with sufficient intensity and duration to crosslink most of the polymerizable mixtures exposed to it.

[0052] "Gel" or "gelling" refers to a degree of polymerization sufficient to stop or substantially slow the movement of a polymerizable mixture deposited on a receiving surface, such that subsequent droplets fuse with the previously deposited polymerizable mixture to form a structure with a single, unstrained mass of polymerizable mixture. Gelated polymerizable mixtures transition to a higher viscosity state but do not reach complete curing. Pinning or gelling (or gelling) enhances flow and shape control and provides a high-quality surface.

[0053] The term "gel point" as used herein refers to the point at which a gel or insoluble portion is formed during the polymerization process. The gel point can also be considered as the degree of conversion at which the liquid polymerization mixture becomes a fixed, highly viscous substance on a stationary surface. The gel point can be determined, for example, using a Soxhlet experiment: the polymer reaction is stopped at different points in time, and the resulting polymer is analyzed to determine the weight fraction of residual insoluble polymer. The data can be extrapolated to the point at which no gel exists. The gel point may also be determined by analyzing the viscosity of the polymerizable mixture during the reaction. Viscosity can be measured using a parallel-plate rheometer, with the polymerizable mixture sandwiched between two parallel plates. At least one plate should be transparent to radiation at the wavelength used for polymerization. The gel point is the point at which the viscosity approaches infinity. The gel point occurs at the same degree of conversion for a given polymer system and given reaction conditions.

[0054] As used here, "inhibitor" refers to a chemical agent or process that slows down or stops a chemical reaction.

[0055] The term "initiator" used here refers to a substance that initiates a chain reaction or polymerization.

[0056] The term "intensity" used here refers to the amount of power transmitted per unit area, where the area is measured on a plane perpendicular to the direction of energy propagation (e.g., watts per square meter (W / m²)). 2 ))

[0057] As used herein, “lens” refers to any ophthalmic device located inside or on the eye. These devices may provide optical correction or may be cosmetic. For example, the term “lens” may refer to contact lenses, intraocular lenses, overlay lenses, ocular implants, optical implants, or other similar devices that correct or modify vision or improve ocular physiology cosmetically without impairing vision (e.g., iris color).

[0058] The term "pinning" used here refers to applying a chemical radiation state, such as exposure to limited chemical radiation, to a gelling process or a sufficient amount of polymerizable mixture that undergoes gelling but does not cause hardening of the polymerizable mixture.

[0059] The term "polymerizable mixture" (sometimes referred to as "PM") as used herein refers to a liquid mixture of components (reactive and possibly non-reactive components) that can polymerize and form polymers or polymer networks when exposed to external energy (e.g., chemical radiation in the range of 280–450 nm, e.g., UV light or blue light or heat). The polymerizable mixture may contain monomers or prepolymer materials that can form ophthalmic lenses that can be cured and / or crosslinked, or modify existing lenses or lens blanks. Various embodiments may include polymerizable mixtures containing one or more additives such as: UV blockers, adhesives, colorants, photoinitiators or catalysts, and other additives desired for ophthalmic lenses such as contact lenses or intraocular lenses. In some embodiments, the polymerizable mixture may also be a hydrogel precursor.

[0060] In this context, the expression "oxygen equilibrium concentration of polymerizable mixture X" is intended to mean the oxygen concentration in the polymerizable mixture obtained when the mixture is brought into equilibrium with an atmosphere having an oxygen concentration of X% at 1.0 atmosphere (1013 millibars).

[0061] Where used herein, the term "optical element" is intended to include, but is not limited to, ophthalmic devices, lenses used in industrial applications, endoscopic lenses, inspection devices, fiber optic devices, camera lenses, telescope lenses, and the like. An embodiment of particular interest at present is the ophthalmic device.

[0062] In some embodiments, the optical element has one or more objects embedded therein, such as an insert, electronic equipment, and a solid object selected from a functional additive release reservoir or depot.

[0063] In other embodiments, the optical element comprises one or more functionally active substances, including biologically active substances.

[0064] The ophthalmic devices used herein are devices located in front of the eyeball, or on the eyeball or on a part of the eyeball including the cornea, eyelids, and ophthalmic glands. These devices may provide optical correction, cosmetic enhancement (e.g., iris color), visual enhancement, therapeutic benefits (e.g., as bandage lenses), or therapeutic agents such as lubricants, wetting agents, anti-inflammatory, anti-allergic, antibacterial, anti-infective, antihypertensive agents, or devices that deliver nutritional supplements, vitamins, antioxidants for eye health, or any combination of the foregoing. Exemplary examples of ophthalmic devices include spectacle lenses, contact lenses (e.g., soft or hard contact lenses), intraocular lenses, overlay lenses, corneal implants such as corneal inlay implants, and selections from ophthalmic / eyepiece insertion devices.

[0065] In some embodiments, the ophthalmic device is a contact lens, in particular a soft contact lens such as a contact lens made of a hydrogel material, and in other embodiments, it may include an intraocular lens made of a hydrogel material.

[0066] The term hydrogel refers to a cross-linked polymer that has absorbed (swelled) water to a water content of at least 10% by weight. Preferably, such a hydrogel material has a water content of at least 20% by weight, for example, at least 25% by weight, and 70-90% by weight.

[0067] Where used herein, the term polymerizable mixture refers to a liquid mixture of components (reactive and possibly non-reactive components) that, upon exposure to external energy (e.g., chemical radiation between 280 and 450 nm (such as UV or blue light) or heat), can undergo polymerization to form polymers or polymer networks. Typically, the mixture includes reactive components such as monomers, macromers, prepolymers, crosslinking agents, and initiators. Furthermore, the polymerizable mixture may further include other components such as wetting agents, release agents, dyes, UV absorbers, and photochromic compounds, any components that can be retained within the resulting ophthalmic device, whether reactive or non-reactive, as well as pharmaceutical, vitamin, antioxidant, and nutritional supplement compounds. It will be understood that a wide range of additives may be added, depending on the ophthalmic device being manufactured and its intended use.

[0068] The fact that a mixture is polymerizable typically suggests that one or more components of the mixture (e.g., monomers, macromers, prepolymers, crosslinking agents, etc.) contain at least one polymerizable functional group, such as (meth)acrylates, (meth)acrylamides, vinyls, N-vinyl lactams, N-vinylamides, and ethylenically unsaturated groups like styryl functional groups.

[0069] In some embodiments, the polymerizable mixture contains at least one hydrophilic component. In some embodiments, the hydrophilic component may be selected from hydrophilic monomers, for example, those known to be useful for preparing hydrogels.

[0070] In some embodiments, hydrophilicity means that at least 5 grams of the compound(s) are soluble in 100 mL of deionized water at 25°C under weakly acidic conditions (pH 5-7) or basic conditions (pH 7-9), and in some embodiments, 10 grams of the compound(s) are soluble in 100 mL of deionized water at 25°C under weakly acidic or basic conditions.

[0071] In contrast to hydrophilicity, hydrophobicity means that 5 grams of a hydrophobic compound does not completely dissolve in 100 mL of deionized water at 25°C under weakly acidic or basic conditions. The solubility of a compound can be confirmed by visual observation; the presence of visible precipitate or turbidity indicates that the compound is hydrophobic. Solubility may also be determined approximately 8 hours after mixing or stirring.

[0072] One class of suitable hydrophilic monomers includes acrylic or vinyl-containing monomers. Such hydrophilic monomers may be used as crosslinking agents on their own, but when hydrophilic monomers having one or more polymerizable functional groups are used, their concentration should be limited as described above in order to provide contact lenses with the desired modulus of elasticity.

[0073] The terms vinyl-type or vinyl-containing monomer refer to monomers that contain a vinyl group (-CH=CH2) and are polymerizable. Examples of hydrophilic vinyl-containing monomers include, but are not limited to, monomers such as N-vinylamide, N-vinyl lactam (e.g., N-vinylpyrrolidone (NVP)), N-vinyl-N-methylacetamide, N-vinyl-N-ethylacetamide, and N-vinyl-N-ethylformamide and N-vinylformamide. Alternative vinyl-containing monomers include, but are not limited to, 1-methyl-3-methylene-2-pyrrolidone, 1-methyl-5-methylene-2-pyrrolidone, and 5-methyl-3-methylene-2-pyrrolidone.

[0074] Acrylic monomers or acrylic-containing monomers are monomers containing an acrylic group (CH2=CRCOX), where R is H or CH3 and X is O or N, and these are also known to polymerize readily. Examples include N,N-dimethylacrylamide (DMA), 2-hydroxyethyl methacrylate (HEMA), glycerol methacrylate, 2-hydroxyethyl methacrylamide, polyethylene glycol monomethacrylate, methacrylic acid, and mixtures thereof.

[0075] Other hydrophilic monomers that may be used in the present invention include, but are not limited to, polyoxyethylene polyols in which one or more terminal hydroxyl groups are substituted with functional groups containing polymerizable double bonds. For example, polyethylene glycol, ethoxylated C1-20 alkyl glucoside, and ethoxylated bisphenol A may be reacted with one molar equivalent or more of terminal cap groups such as isocyanatoethyl methacrylate, methacrylic anhydride, methacryloyl chloride, and vinyl benzoyl chloride to produce polyethylene polyols having one or more terminally polymerizable olefin groups bonded to polyethylene polyols via linking sites such as carbamate groups or ester groups. Other suitable hydrophilic monomers will be apparent to those skilled in the art.

[0076] In some embodiments, the hydrophilic component comprises at least one hydrophilic monomer, such as DMA, HEMA, glycerol methacrylate, 2-hydroxyethyl methacrylamide, NVP, N-vinyl-N-methylacrylamide, polyethylene glycol monomethacrylate, and combinations thereof. In another embodiment, the hydrophilic monomer comprises at least one of DMA, HEMA, NVP, and N-vinyl-N-methylacrylamide and mixtures thereof. In yet another embodiment, the hydrophilic monomer comprises DMA and / or HEMA.

[0077] Hydrophilic components(s) (e.g., hydrophilic monomers(s)) may be present in a wide range of amounts depending on the specific balance of desired properties. In some embodiments, the amount of hydrophilic components is up to 60% by weight, such as 5% to 40% by weight, based on the total reactive components.

[0078] A hydrophobic silicone-containing component (or silicone component) is one that contains at least one [-Si-O-Si] group in a monomer, macromer, or prepolymer. In some embodiments, Si and attached O are present in the silicone-containing component in amounts exceeding 20% ​​by weight, such as more than 30% by weight, relative to the total molecular weight of the silicone-containing component. Useful silicone-containing components include polymerizable functional groups such as acrylates, methacrylates, acrylamides, methacrylamides, N-vinyl lactams, N-vinylamides, and styryl functional groups.

[0079] Furthermore, in some embodiments, the crosslinkable monomers may be used alone or in combination and may include ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, glycerol trimethacrylate, polyethylene glycol dimethacrylate (wherein polyethylene glycol has a molecular weight of, for example, up to 400), and other polyacrylates and polymethacrylate esters. The crosslinkable monomers may be used in a typical amount, for example, 0.1 to 5, preferably 0.2 to 3, per 100 parts by weight of the polymerizable mixture.

[0080] Another monomer that may be used is methacrylic acid, which is used to influence the amount of water absorbed by the hydrogel at equilibrium. Methacrylic acid is typically used in an amount of 0.2 to 8 parts by weight per 100 parts by weight of hydrophilic monomers such as HEMA. Other monomers that may be present in the polymerization mixture include methoxyethyl methacrylate and acrylic acid.

[0081] In the embodiment, the polymerizable mixture comprises hydroxyethyl methacrylate (HEMA) or hydroxyethyl acrylate (HEA) monomer, preferably hydroxyethyl methacrylate (HEMA) monomer.

[0082] In the embodiment, the polymerizable mixture includes a methacrylate monomer or acrylate monomer that is not a hydroxyethyl methacrylate monomer or a hydroxyethyl acrylate monomer.

[0083] In the embodiment, the polymerizable mixture includes a reactive silicone monomer or oligomer.

[0084] In a further embodiment, the polymerizable mixture after polymerization provides a polymer that is non-swelling in water, for example, a polymer that cannot absorb more than 2% by weight of water.

[0085] One or more polymerization initiators may be included in the polymerizable mixture. Examples of polymerization initiators include, but are not limited to, compounds that generate free radicals at moderately elevated temperatures, such as lauryl peroxide, benzoyl peroxide, isopropyl percarbonate, and azobisisobutyronitrile, as well as photoinitiator systems such as aromatic alpha-hydroxyketones, alkoxybenzoin, acetophenone, acylphosphine oxide, bisacylphosphine oxide, and tertiary amine + diketone, and mixtures thereof. Examples of photoinitiators include 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, bis(2,6-dimethoxybenzoyl)-2,4-4-trimethyl)ylpentylphosphine oxide (DMBAPO), bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (Irgacure 819), 2,4,6-trimethylbenzyldiphenylphosphine oxide and 2,4,6-trimethylbenzoyldiphenylphosphine oxide, benzoin methyl ester and camphorquinone with ethyl 4-(N,N-dimethylamino)benzoate. Commercially available ultraviolet and visible light initiator systems include, but are not limited to, Irgacure 819® and Irgacure 1700® (from Ciba Specialty Chemicals) and Lucirin TPO initiator (available from BASF). Commercially available UV photoinitiators include Irgacure 651, Darocur 1173, and Darocur 2959 (Ciba Specialty Chemicals). These photoinitiators and other photoinitiators may be used and are disclosed in Volume 3, "Photoinitiators for Free Radical Cation and Anionic Photopolymerization, 2nd Edition," by JVCrivello & K. Dietliker, edited by G. Bradley, published by John Wiley and Sons, New York, 1998.

[0086] In some embodiments, the polymerization initiator is included in the polymerizable mixture in an amount that may initiate polymerization of the polymerizable mixture, such as 0.1 to 2% by weight. Polymerization of the polymerizable mixture may be initiated using heat, visible light, ultraviolet light, or other appropriate energy, depending on the polymerization initiator used. Alternatively, in some embodiments, initiation may be carried out without a photoinitiator, for example, using an e-beam. However, if a photoinitiator is used, preferred initiators are bisacylphosphine oxides such as bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (Irgacure 819®) or a combination of 1-hydroxycyclohexylphenyl ketone and DMBAPO, and in another embodiment, the method of polymerization initiation is via visible light activation.

[0087] In some embodiments, the polymerizable mixture may contain one or more internal wetting agents. These internal wetting agents include, but are not limited to, high molecular weight hydrophilic polymers. Examples of internal wetting agents include, but are not limited to, polyamides such as poly(N-vinylpyrrolidone) and poly(N-vinyl-N-methylacetamide).

[0088] Internal wetting agents may be present in a wide range of amounts depending on the desired specific parameters. In some embodiments, the amount of wetting agent(s) is up to 50% by weight, such as 5-40% by weight, 6-30% by weight, etc., based on the total reactive components.

[0089] Furthermore, the polymerizable mixture may contain one or more auxiliary components selected from, but not limited to, chelating agents, polymerization inhibitors, viscosity modifiers, surface tension modifiers, glass transition modifiers, compatibilizers, ultraviolet absorbing compounds, pharmaceuticals such as ophthalmic pharmaceuticals and ophthalmic anti-inflammatory agents, excipients, antimicrobial compounds, copolymerizable and nonpolymerizable dyes, release agents, reactive hues, pigments, and chelating agents, and combinations thereof. In some embodiments, the total amount of such auxiliary components may be up to 20% by weight. Preferred embodiments may include a photoinitiator that generates reactive species when exposed to one or more of visible light, ultraviolet light, red light, and infrared light, and may also include one or more of the visible light, ultraviolet light, red light, and infrared light absorbing moieties.

[0090] Polymerizable mixtures may be prepared, for example, by simply mixing the components of the mixture. In some embodiments, reactive components (e.g., hydrophilic monomers, wetting agents, and / or other components) are mixed with an inert diluent to form a polymerizable mixture. Such diluents may have the effect of controlling the expansion of the ophthalmic device formed when hydrated, assisting the solubility of the components, and regulating the glass transition temperature. In other embodiments, the inert diluent may be omitted.

[0091] Suitable diluents include, but are not limited to, alcohols having 3 to 20 carbon atoms, amides having 10 to 20 carbon atoms derived from primary amines, ketones having 3 to 10 carbon atoms, ethers, polyethers, and carboxylic acids having 8 to 20 carbon atoms. As the number of carbon atoms increases, the number of polar moieties may also increase to provide the desired level of water miscibility. In some embodiments, primary and tertiary alcohols are preferred. Preferred classes include alcohols having 4 to 20 carbon atoms and carboxylic acids having 10 to 20 carbon atoms.

[0092] In some embodiments, the diluent is selected from 1,2-octanediol, t-amyl alcohol, 3-methyl-3-pentanol, decanoic acid, 3,7-dimethyl-3-octanol, 2-methyl-2-pentanol, 2-ethyl-1-butanol, 3,3-dimethyl-2-butanol, tripylene methyl ether (TPMEX), butoxyethyl acetate, and mixtures thereof.

[0093] In some embodiments, the diluent is selected from those that have some solubility in water. In some embodiments, at least about 3% of the diluent is miscible with water. Examples of water-soluble diluents include, but are not limited to, 1-octanol, 1-pentanol, 1-hexanol, 2-hexanol, 2-octanol, 3-methyl-3-pentanol, 2-pentanol, t-amyl alcohol, tert-butanol, 2-butanol, 1-butanol, ethanol, decanoic acid, octanoic acid, dodecanoic acid, 1-ethoxy-2-propanol, 1-tert-butoxy-2-propanol, EH-5 (commercially available from Ethox Chemicals), 2,3,6,7-tetrahydroxy-2,3,6,7-tetramethyloctane, 9-(1-methylethyl)-2,5,8,10,13,16-hexaoxaheptadecane, 3,5,7,9,11,13-hexametrioxy-1-tetradecanol, and mixtures thereof. Alcohol esters, such as boric acid esters of alcohols, are other embodiments of the diluent.

[0094] In some embodiments, the preferred amount of diluent is typically up to 60% by weight, such as 20-50% by weight, such as 10-60% by weight, based on the complete polymerizable mixture.

[0095] In other embodiments, in some embodiments, the polymerizable mixture comprises, based on the weight of the polymerizable mixture, one or more crosslinking agents in an amount of 0.5 to 5.0% by weight, one or more nonreactive diluents in an amount of 0 to 60.0% by weight (e.g., polyhydric alcohols, esters of polyhydric alcohols, or ethers of polyhydric alcohols such as glycerol and glycerol esters), and one or more polymerization inhibitors in an amount of less than 100.0 ppm and preferably less than 50.0 ppm (e.g., glycerol and glycerol esters). The viscosity of the polymerizable mixture may also play an important role, typically 1 to 25 cP, for example 2 to 15 cP, and particularly 3 to 10 cP, but other viscosities are also within the scope of the present invention.

[0096] As described above, the oxygen equilibrium concentration of the polymerizable mixture is preferably in the range of 0.05 to 8.0% by volume, for example, 0.2 to 6.0% by volume, for example, 0.5 to 6% by volume. The lower limit (0.05%, 0.1%, 0.2%, etc.) is stated for practical reasons, and it is quite possible to achieve even lower concentrations.

[0097] The oxygen content of the polymerizable mixture may be adjusted to a desired level (X) by exposing the polymerizable mixture (which had previously been mixed under ambient atmosphere (10¹³ mbar, 21 vol. % O₂)) to a reduced pressure P, where P = X * 10¹³ / 21 mbar. The reduced pressure (sometimes called a "vacuum") may then be released, and the oxygen-adjusted polymerizable mixture may be stored in an atmosphere having an oxygen concentration corresponding to a preferred atmosphere having an oxygen concentration of X.

[0098] In some preferred embodiments, the oxygen concentration in the controlled ambient atmosphere is lower than the oxygen equilibrium concentration in the polymerizable mixture, both in the deposited polymerizable mixture and in the substrate in contact with the polymerizable mixture.

[0099] 3D printing devices The deposition of multiple droplets is typically achieved using an additive manufacturing printhead. Such a printhead can simultaneously deposit either a one-dimensional pattern (line shape) or a two-dimensional pattern of multiple droplets of liquid. In some embodiments, the droplets are preferably in a smaller range for additive manufacturing, such as approximately 3 to 20 picoliters per droplet, and preferably 10 to 30 passes of the printhead across the substrate.

[0100] In some embodiments, the desired rate and precision of deposition of multiple droplets may be achieved with an additive manufacturing print head capable of simultaneously depositing two-dimensional patterns of polymerizable mixtures, so that patterns (or multiple consecutive patterns) of polymerizable mixture droplets representing an integer map (e.g., a grayscale image) of the energy transmittance of an ophthalmic device can be printed.

[0101] In some preferred embodiments, such as those used to form the embodiments disclosed herein, a two-dimensional pattern representing an integer map of energy transmittance in the form of a grayscale image can be achieved in a single pass of a printhead depositing droplets over an area of ​​at least the size of an ophthalmic device. A commercially available printhead suitable for this purpose is the Fujifilm Samba® printhead, e.g., the Samba® G3L printhead, which has 2048 nozzles per module and is capable of depositing liquids with native drop sizes on the order of 2.4 picoliters to a maximum drop size of 13.2 picoliters with an accuracy of 1200 native dpi.

[0102] The pattern of each path of a droplet deposited by a 3D printing device may be determined in relation to the desired transmittance pattern of the optical lens formed and the shape of the optical lens formed, which correlates with the transmittance pattern. For example (in the case of an ophthalmic device), data collected from measuring the patient's eye may be used to generate the input. The data may include, for example, optical properties, surface properties, size and shape dimensions, and observations of the state of eye disease.

[0103] A three-dimensional (3D) printable model may be created based on a computer-aided design (CAD) pad cage or a scan of a patient's eye. A patient's eye scan may involve collecting and analyzing digital data representative of the shape and appearance of the patient's eye. Based on the collected data, a three-dimensional model of the ophthalmic device in question may be created. The three-dimensional model may be processed by software to convert the model into a grayscale image (or other energy intensity mapping), generate a file containing instructions tailored to a specific type of 3D printer, and repeatedly apply a polymerizable mixture according to the grayscale image or other energy transmission pattern.

[0104] substrate The present invention provides a method for depositing multiple droplets of a polymerizable mixture onto the surface of a substrate. Suitable substrate materials include one or more of glass, polyolefins such as polypropylene, polystyrene, and other smooth materials.

[0105] In some preferred embodiments, the shape of the substrate represents the shape of one side of the resulting (non-hydrating) ophthalmic device, and may include at least a portion that is, for example, curved or otherwise curved for a contact lens and relatively flat for an intraocular lens. The size of the substrate is preferably adjusted to fit the required dimensions of the finished hydrating ophthalmic device. Substrates with a rotation axis may be formed by one or more of turning, grinding, and injection molding. Substrates not limited to having a rotation axis may be manufactured by other processes such as 3D printing. The substrate may therefore include non-spherical optical surface shapes, such as a substrate surface shape based on a portion of the patient's eye exposed to air.

[0106] In some embodiments, to adjust the wettability of the substrate surface receiving the polymerizable mixture, the substrate surface may be pre-treated with a surfactant, exposure to UV, exposure to ozone, and / or plasma treatment, or a combination of these treatments. In some preferred embodiments, the receiving surface of a glass or polymer substrate may be pre-treated with a silicone surfactant such as Tween 80, or Dow Corning Additive 67, Additive 14, Additive 57, or Xiameter OFX-0193. In some embodiments of the present invention, the surfactant may be included in the polymerizable mixture.

[0107] In some embodiments, the method for manufacturing an ophthalmic lens includes bringing the oxygen concentration in the substrate to equilibrium with the oxygen concentration in a controlled atmosphere. Similarly, in some preferred embodiments, the oxygen concentration in the substrate is equal to or less than the oxygen content of the polymerizable mixture deposited on the substrate.

[0108] To obtain an oxygen concentration in the substrate that is in equilibrium with the oxygen concentration in the controlled atmosphere, the substrate may be exposed to a controlled atmosphere (or a corresponding atmosphere) for, for example, a period of at least 8 hours before droplet deposition.

[0109] In some embodiments, the substrate may utilize only a limited amount of oxygen internally, and therefore, no special precautions may be required regarding the oxygen concentration within the substrate.

[0110] In alternative embodiments, the substrate itself is an ophthalmic device (e.g., a regular commercially available contact lens) which is modified by the methods described herein to form a final ophthalmic device (e.g., an ophthalmic device having one or more different optical properties, an ophthalmic device having a modified color pattern, an ophthalmic device having different physical properties, etc.).

[0111] Controlled atmosphere In some embodiments, the ambient atmosphere in which the deposition printing described herein is performed may be controlled. The controlled ambient atmosphere may, in non-limiting examples, include a specified range of specific gases, a specified range of particulate matter, and one or both of controlled wavelengths of light or other energy wavelengths. In some preferred embodiments, this is achieved in an atmosphere containing preferably low concentrations of oxygen to appropriately control the oxygen content of the polymerizable mixture. In some embodiments, the receiving surface of the substrate may be contained within the controlled ambient atmosphere.

[0112] As a specific, non-limiting example, in some embodiments, the controlled atmosphere has an oxygen concentration of at most 5.0 volume%. In some embodiments, the oxygen concentration in the controlled atmosphere is at most 2.0 volume%, for example, in the range of 0.01 to 2.0 volume%, for example, 0.03 to 1.5 volume%, for example, 0.05 to 1.2 volume%, for example, 0.1 to 1.1 volume%, and more preferably at most 1.0 volume%. The lower limits (e.g., 0.01%, 0.03%, 0.05%, etc.) are stated for practical reasons, and it is quite possible to achieve even lower concentrations.

[0113] In another embodiment, in some embodiments, the controlled atmosphere in which the polymerizable mixture is deposited is most conveniently 1.0 atm. (10¹³ mbar), which corresponds to an oxygen concentration of 21 vol%. Oxygen concentrations lower than 21 vol% found in normal atmosphere may preferably be obtained by mixing atmospheric air with other gases, such as inert gases, in some preferred embodiments, one or more of nitrogen, helium, argon, or other inert gases.

[0114] In some embodiments, the controlled atmosphere may include an inert gas such as nitrogen mixed with pure oxygen in a specific amount. One preferred approach for the controlled atmosphere is to use nitrogen as the inert gas to replace atmospheric oxygen, thereby achieving a desired level of oxygen concentration.

[0115] The oxygen concentration is monitored by an oxygen concentration meter and adjusted before the additive manufacturing process, at the start of the additive manufacturing procedure, and during the manufacturing process, and preferably intermittently or continuously during the process of preparing one or both of the optical elements and the substrate.

[0116] droplet adhesion and curing The method of the present invention involves a series of deposition passes of multiple droplets of a polymerizable mixture onto a substrate and one or both of the surfaces of previously deposited droplets, under a controlled atmosphere. The droplets of the polymerizable mixture are preferably emitted from a print head and deposited based on a two-dimensional pattern representing an energy transmittance pattern, such as a grayscale image (or other light map representing light intensity). Following the deposition of the droplets of the polymerizable mixture, the droplets may be exposed to a controlled amount of chemical radiation to induce a gelation process that pins the droplets of the polymerizable mixture to the substrate in place.

[0117] Polymerizable mixtures are typically deposited using 3D printing devices, such as the printing devices described herein. In embodiments, individual droplets have a volume of 0.5 to 50 pL, for example, 1 to 40 pL, or 1.5 to 30 pL, such as 2.0 to 15 pL.

[0118] In some embodiments, each of several droplets of the polymerizable mixture is deposited on a surface relative to the substrate. The surface relative to the substrate may include droplets in contact with one or more of the following: the top surface of the substrate, previously deposited droplets, and a molded article placed on either or both of the substrate and the previously deposited droplets of the polymerizable mixture. Polymerizable mixture deposited on top of previously deposited polymerizable mixture may integrate with the previously deposited polymerizable mixture so that a single mass of polymerizable mixture is formed on the substrate without any distinguishable layers. After contact with the surface, the polymerizable mixture may be exposed to limited chemical radiation or heat after the deposition of the final layer of a continuous layer of droplets for forming an ophthalmic device. Droplets of polymerizable mixture deposited on the molded article may adhere to the molded article. The molded article may have a surface treated with a wetting agent.

[0119] In a variation of the present invention in which a continuous disposal layer of deposited polymerizable mixtures is exposed to chemical radiation (e.g., UV light), the polymerizable mixture may contain a photoinitiator. In a variation of the present invention in which polymerizable materials arranged in a continuous path are exposed to heat, the polymerizable mixture may contain a thermal initiator.

[0120] In some variations of the present invention, a continuous pattern is exposed to intermittent radiation (e.g., UV light) after each deposition of droplet layers. The degree of polymerization achieved by such intermittent exposure to chemical radiation is typically required to pin the polymerizable mixture or to control the migration of deposited droplets from one position to another, thereby obtaining gelation in another manner. In preferred embodiments, such control of migration allows for a limited flow of the deposited polymerizable mixture but prevents uncontrolled rearrangement of the deposited polymerizable mixture. For example, in some embodiments, controlled migration allows gravity to integrate the deposited droplets with the previously deposited polymerizable mixture and then fuse them to a smoothed surface of the polymerizable mixture, which is then pinned in place during the gelation process.

[0121] In some embodiments of the present invention, multiple droplets of a polymerizable mixture are deposited on a surface containing either or both a substrate and a previously deposited polymerizable mixture, thereby forming a pattern of the polymerizable mixture having energy transmittance characteristics based on an integer map representing energy transmittance, such as a two-dimensional grayscale image referenced for controlling a print head.

[0122] The deposited polymerizable mixture is preferably exposed to pinning chemical radiation after each pass (or several passes) of the printhead that deposits the polymerizable mixture, and finally exposed to curing chemical radiation after the final pass of the printhead that deposits the droplet polymerizable mixture to form optical elements.

[0123] The printhead path may include the movement of the printhead relative to the substrate upon which the polymerizable mixture is received, the substrate, and the previously deposited polymerizable mixture relative to the printhead, and / or the movement of the printhead and the substrate relative to each other as the polymerizable mixture is deposited. In some preferred embodiments, at least a portion of the pattern of polymerizable mixture deposited via the path following the first pass of the printhead combines with and integrates with the previously deposited polymerizable mixture, thereby forming a single volume portion of polymerizable mixture. Gravity induces limited movement of the deposited polymerizable mixture, resulting in a smooth surface of the deposited polymerizable mixture, and gravity-based movement may be limited by surface tension and minute forces. Preferably, the single volume portion of polymerizable mixture is pinned and / or gelled by exposure to a limited amount of chemical radiation, thereby limiting additional movement following the smoothing effect of gravity-induced movement.

[0124] In some variations of the present invention, a series of consecutive passes of a print head, e.g., 2 to 20 passes of the polymerizable mixture, are deposited before exposure to intermittent chemical radiation effective in pinning and / or gelling the deposited polymerizable mixture. Prior to exposure to intermittent chemical radiation, the deposited polymerizable mixture may undergo a limited migration as a single volume portion of the polymerizable mixture.

[0125] In some embodiments, the amount of polymerizable mixture deposited in one pass of the print head on any particular portion of the receiving surface may be up to 50 μm, but is preferably up to 25 μm.

[0126] In some variations of the present invention, the polymerizable mixture comprises multiple photoinitiators, where two or more photoinitiators are responsive to chemical radiation of different wavelengths. This is particularly interesting when it is desirable to utilize UV ​​light of one wavelength for intermittent exposure (for pinning or gelling) and UV light of another wavelength for the final curing of the polymerizable mixture deposited to form optical elements. Thus, in some variations of the present invention, a first polymerization initiator is used (in conjunction with appropriate exposure to a first chemical radiation) to create a partially polymerized polymerizable mixture construct, and a second polymerization initiator is used (in conjunction with appropriate exposure to a second chemical radiation) to complete the curing process.

[0127] In addition to controlling the level of oxygen in the polymerizable mixture to within a desired oxygen content range, some embodiments of the present invention include controlling the polymerization of the deposited polymerizable mixture to produce an optical element using the process described herein, wherein the degree of polymerization of the deposited polymerizable mixture within a specified time frame after deposition is limited to a degree of gelation that stops or substantially slows down the migration of the polymerizable mixture, while allowing droplets from subsequent passes to fuse with the previously deposited polymerizable mixture to form a strain-limited optical element structure.

[0128] The process for intermittent gelation is often referred to as pinning or gelling of the deposited polymerizable mixture. In some variations of the present invention, the pinning process may include applying a dose of chemical radiation at an intensity, wavelength, and duration suitable for inducing gelation, such as applying ultraviolet (UV) light to a UV-curable polymerizable mixture and / or ink (UV ink). The wavelength of the chemical radiation may be matched to the photochemical properties of the polymerizable mixture and / or UV ink used in the manufacturing process.

[0129] As a result of intermittent gelation, the deposited polymerizable mixture and / or ink droplets move to a higher viscosity state but do not reach full curing. Variations of the present invention, including pinning or gelling (or gelling), improve the ability to control the flow and morphology of the deposited polymerizable mixture, thereby providing high optical quality in the optical element formed through the final curing of the deposited polymerizable mixture. For example, sufficient flow is preferred, allowing gravity to smooth the surface of the gelled polymerizable mixture but without significantly altering the shape of the optical element. In some variations, other forces, such as centrifugal force, may be used to form the surface shape.

[0130] The gelation and curing steps may be modified based on the selection and / or concentration of one or more of the following: photoinitiator, crosslinking agent, source of chemical radiation (e.g., UV light source), intensity of chemical radiation, and irradiation time. Examples of sources of chemical radiation may include light-emitting diodes (LEDs) or light bulbs, lasers, etc.

[0131] In some specific embodiments, two photoinitiators absorbing at two different wavelengths are used with corresponding UV LED light sources (e.g., 365 nm and 400 nm). One initiator may be present at a concentration sufficient to initiate gelation of the polymerizable mixture but insufficient to complete polymerization. This allows individual layers to have the same relative degree of conversion before final curing. The final polymerization of the entire optical element may be carried out as a separate step using another photoinitiator / UV LED light combination (e.g., the chemical radiation energy of a second photoinitiator, or the chemical radiation energy of a third photoinitiator), where the chemical radiation energy results in a uniform polymer network necessary for the optical function.

[0132] As an alternative, a thermal initiator active at or above Tg may be used in place of, or in addition to, a second (or other) photoinitiator to complete the curing of the deposited polymerizable mixture. The present invention also provides that, throughout the deposition process steps and during the final curing step, without control of the oxygen content of the deposited polymerizable mixture, oxygen inhibition effects can adversely affect the uniformity of the polymer network, potentially leading to the formation of incompletely cured polymers and, consequently, devices with sticky surfaces.

[0133] In some embodiments, when the polymerizable mixture is deposited on a curved surface, the first deposit, or a plurality of deposits, may be deposited on the curved surface as a pattern of droplets of the polymerizable mixture according to the method described herein. The droplet pattern includes a volume and distribution that allows for surface tension, thereby maintaining the pattern of droplets of the polymerizable mixture in a limited flow or other movement until it partially hardens in a gelling step that pins the deposited polymerizable mixture in place.

[0134] Subsequent deposition of additional droplets from the print head may fill the spaces left by the initial deposition or subsequent layers until the surface of the receiving substrate is completely covered and established as a foundation for constructing optical elements thereon. Alternatives to the dot pattern include depositing droplets to form very thin layers (e.g., 1 to 8 microns) and constructing optical elements on such very thin layers in the processes disclosed herein.

[0135] In some embodiments, it is useful to isolate the printhead containing monomers from exposure to chemical radiation such as UV radiation in order to prevent premature gelation or polymerization of monomers within the printhead, which could render the printhead inoperable or allow it to operate at a reduced performance level. Isolation from chemical radiation is particularly important when using reactive monomers containing low levels of inhibitors and / or when using the printhead in a low-oxygen environment.

[0136] To achieve simultaneous printing and pinning of materials in order to stop or slow the movement of ink or polymerizable mixture once deposited, some embodiments of the present invention include a device that can operate to isolate a chemical radiation source (e.g., a UV light source) from the print head, thereby essentially eliminating or substantially reducing the possibility of gelation / polymerization of the polymerizable mixture within the print head. Isolating the print head from a chemical radiation source and controlling both oxygen levels and the movement of the polymerized mixture allows for the fabrication of precise shapes and optical devices without artifacts in the matrix that adversely affect the optical performance of the final lens produced.

[0137] In some embodiments, after the multiple deposition and gelation steps of the polymerizable mixture (one or more) are completed but before the final curing step is performed, it is preferable to wash the gelled and deposited polymerizable mixture with a solvent or water to remove, for example, excess monomers.

[0138] Referring next to Figure 1, the schematic diagram shows an example of an additive manufacturing system 100 comprising the apparatus and its underlying software, the software enabling the apparatus when it is run. As shown, the additive manufacturing system 100 includes one or more additive manufacturing printing devices 101-102, which are operable to deposit droplets 110 of polymerizable mixture 103 onto a receiving surface 103A supported by a substrate 104 in a pattern of energy intensity and / or energy transmittance (e.g., a grayscale pattern). The receiving portion 104A of the substrate 104 may be smooth and arc-shaped to be suitable as a back curve of a contact lens. The receiving surface 103A may include one or both of a predetermined receiving portion 104A of the substrate 104 and the previously deposited polymerizable mixture 103.

[0139] One or more chemical radiation sources 105 and 106 (which may include LEDs emitting the same or different wavelengths of energy).

[0140] Some variations of the present invention include a housing 114 having one or more ports 107 and 108 for providing a controlled atmosphere 109 within the housing 114. The housing 114 may include an atmosphere surrounding and encompassing one or more of the following: a substrate 104, printing devices 101-102, a polymerizable mixture 103 accumulated on the droplet 110 substrate (positioned to form an ophthalmic lens such as a contact lens), and a source of chemical radiation 105-106.

[0141] In some embodiments, the substrate 104 is positioned in close proximity to, for example, below, at least one 3D printing device 101-1-2. The relationship of below or downward is derived from the direction of gravity. The printing devices 101-102 operate to eject droplets of polymerizable mixture 110 onto a receiving surface 103A. The receiving surface 103A may include one or more of the following: the surface of the receiving portion 104A of the substrate 104, the surface of the previously deposited polymerizable mixture 103, and the receiving portion of an insert such as a hard lens or electronic device. The droplets are deposited in a pattern that reproduces an energy transmittance pattern, such as a grayscale image. The continuous deposition of the pattern aggregates to form a volume of polymerizable mixture in the desired shape of the target optical element (see, for example, Figures 4-5).

[0142] After a droplet 110 of the polymerizable mixture is applied to a receiving surface 103A to form a volume portion 103 of the polymerizable mixture, the polymerizable mixture may be exposed to a first dose of chemical radiation (which is a first wavelength range, a first duration, and a first intensity (e.g., ultraviolet or blue light)). In some embodiments, a dose of chemical radiation within the first range may be supplied to the deposited polymerizable mixture via a first chemical radiation source 105. Final curing may be achieved by exposing the aggregated polymerizable mixture to a second dose of chemical radiation (which includes a second wavelength range, a second duration, and a second intensity), which may be supplied from the same chemical radiation source 105 or a different chemical radiation source 106. Final curing will allow the molded product, such as an ophthalmic lens 111, to be removed from the substrate.

[0143] In some variations of the present invention, the final curing step may be additionally carried out in an environment having a controlled temperature, such as a temperature higher than ambient room temperature.

[0144] According to some embodiments, a first print head 101 of system 100 may provide a first polymerizable mixture, and a second print head 102 may provide a second polymerizable mixture, which may be compositionally the same as or different from the first polymerizable mixture, and which may include a functional additive or a non-polymerizable mixture (e.g., a functional additive or a solvent containing a functional additive).

[0145] Ambient conditions within system 100 may be controlled, for example, with respect to the oxygen content of the controlled atmosphere 109, and in some embodiments, almost all variables that may affect one or more of the following: temperature, ambient light, amount of particulate matter, size of particulate matter, circulation or other movement of the ambient atmosphere, and movement of unpinned, unpolymerized deposited polymerizable mixture, polymerization of the deposited polymerizable mixture, and the shape of the device formed by the polymerization of the deposited polymerizable mixture.

[0146] Under conditions that the substrate 104 is permeable to or transparent to chemical radiation, both or either of the radiation sources 105 and 106 may be positioned individually or in alternating combinations below or at an angle to the substrate 104, as shown in Figure 1. In addition, shutters or other chemical radiation shields may be positioned above or to the lateral sides of the receiving surface. The shutters or other chemical radiation shields are positioned and function to shield the print head from chemical radiation or other chemical radiation conditions.

[0147] The properties of the surrounding gaseous environment can be controlled, for example, by using nitrogen gas purging through inlets 107 and 108. Purging may be performed to increase or decrease the oxygen partial pressure to a predetermined level.

[0148] Referring next to Figure 2, the schematic diagram shows several alternative embodiments that may be incorporated within the 3D additive manufacturing system 200. Some of the same reference numerals as in Figure 1 are used (e.g., 3D print heads 101-102, chemical radiation sources 105 and 106, substrate 104, housing 114 having one or more ports 107 and 108, and a controlled atmosphere for the deposited polymerizable mixture 110). Furthermore, the embodiments shown in Figure 2 include an oxygen sensor 204, a gate 205 for moving components in and out of the housing 114, a UV shielding screen 112, and an actuation structure 203 (e.g., belt-driven or stepping motor linear-driven) configured to provide relative movement between the substrate 104 and one or more 3D print heads 101-102 and / or relative movement with one or more chemical radiation sources 105-106.

[0149] The 3D printing system 200 shown is similar to that in Figure 1, as shown in Figure 2, and also includes a substrate 104 and one or more actuators 201-203 configured (and operable) to provide relative movement between the 3D printing heads 101-102, chemical radiation sources 105-106, and one or more of the chemical radiation sources 105-106, and in some embodiments, a shielding screen 112 and / or housing. In some embodiments, the printing head actuator 201 is configured (and operable) to move one or more of the printing heads 101-102 relative to the substrate 104. Similarly, the radiation source actuator 203 is configured (and / or operable) to move one or more chemical radiation sources 105-106 relative to the substrate 104. The substrate actuator 203 is configured (and / or operable) to move the substrate 104 relative to one or both of the printing heads 101-102 and the chemical radiation sources 105-106. While a belt drive 203A is shown as actuation structure 203 and stepping motor tracks are shown as actuation structures 201-202, other devices and apparatus are also within the scope of the present invention. Actuation structures 201-203 may be synchronized so that the relative movement between one or more of the substrate 104, print heads 101-102, and chemical radiation sources 105-106 can be coordinated with the deposition of polymerizable material 110 from the print heads 101-102.

[0150] The process described herein may be carried out in systems 100, 200 described for forming an optical element 211. The process may include the operation of one or more print heads 101-102, each having a first print head 101 for ejecting droplets 110 of a first polymerizable mixture, and one or more additional print heads 102 for ejecting droplets 110A of a composition which may include the first polymerizable mixture, a second polymerizable mixture compositionally different from the first polymerizable mixture, and a nonpolymerizable substance or mixture.

[0151] In some embodiments, one or more of the first polymerizable mixture, the second polymerizable mixture, and the non-polymerizable mixture include one or more functionally active substances, such as substances in soluble form.

[0152] Release and post-processing of ophthalmic devices from the substrate. After sufficient deposition of the polymerizable mixture 103 to form the optical element 211 (e.g., an ophthalmic device) and after the curing process, the optical element 211 is typically released from the substrate. It is preferable that the polymerizable mixture 103 deposited in a specific pattern to form the optical element 211 is sufficiently physically bonded to the substrate 104 during the preparation of the optical element 211 to prevent unwanted migration relative to the substrate 104; however, the polymerizable mixture 103 should not be bonded so securely that removing the optical element 211 from the substrate 104 would damage the optical element 211. For example, in some embodiments, care should be taken to avoid the formation of covalent bonds between the polymerizable mixture 103 and the substrate 104 during the preparation of the optical element 211, including the curing of the polymerizable mixture 103.

[0153] The optical device 211 may be released (or otherwise removed) from the substrate 104 by physical means so that the optical element 211 can be manipulated in various ways. For example, the optical element may be manipulated by one or more of the following: washing the optical element 211 to remove by-products, immersing the optical element 211 in buffered saline, or coloring, marking, and packaging the optical element 211. For example, in some modifications of the present invention, such as when the optical element 211 is formed of a hydrogel polymer, the optical element 211 may be immersed in one or both of a solution such as water and buffered saline so that the optical element 211 expands. The expansion facilitates the release of the optical element 211 from the substrate 104. The solution may also contain one or more release agents. The release agents may include compounds, or mixtures of compounds, that, when combined with water, reduce the time required to release the optical element 211 from the substrate 104 compared to the time required to release such optical element 211 using an aqueous solution without a release agent.

[0154] While typically preferable, it is not strictly necessary for the curing of the optical element 211 to be completed before it is released from the substrate 104.

[0155] In some embodiments, after curing, the optical element 211 is subjected to one or more extraction steps to remove unreacted components from the optical element 211. The extraction steps may be carried out using one or more of the following: conventional extraction fluids, organic solvents, alcohols, water (or aqueous solutions such as buffered saline). In various embodiments, extraction can be achieved, for example, by immersion of the lens in an aqueous solution or exposure of the lens to a stream of aqueous solution. In various embodiments, extraction may also include, for example, one or more of the following: heating the aqueous solution, stirring the aqueous solution, raising the level of the release agent in the aqueous solution to a level sufficient to cause the lens to release, stirring the lens mechanically or ultrasonically, and incorporating at least one elution agent into the aqueous solution to a level sufficient to sufficiently remove unreacted components from the lens. The above may be carried out in batch or continuous processes with or without additional heat, stirring or both. The ophthalmic device may also be sterilized by known means such as autoclaving and radiation sterilization, but is not limited to these. Sterilization may be carried out before or after packaging the optical element 211 in a suitable storage container, preferably after packaging. In some preferred embodiments, the optical element 211 is packaged in an aqueous solution.

[0156] In the case of the optical element 211 formed of hydrogel, the packaging may include packaging in a saline solution containing approximately 0.9% sodium chloride and a suitable buffer such as a phosphate buffer or a borate buffer. Furthermore, the packaging solution may contain one or more functional active substances, including biologically active substances.

[0157] The aqueous solution may also contain additional water-soluble components such as mold release agents, wetting agents, lubricants, active pharmaceutical ingredients (APIs), vitamins, antioxidants, and nutritional supplement ingredients, or combinations thereof. In some embodiments, the aqueous solution contains an organic solvent such as isopropyl alcohol in less than 10% by weight, in other embodiments less than 5% by weight, and in yet another embodiment no organic solvent, depending on the composition of the aqueous solution. The aqueous solution may or may not require special handling such as purification, recycling, or special disposal procedures.

[0158] In some embodiments, the aqueous content of the hydrogel optical element 211 includes at least 30% by weight of water, at least 50% by weight of water in some embodiments, at least 70% by weight of water in some embodiments, and 90% by weight of water in other embodiments.

[0159] In a variation of the present invention, the polymerizable mixture 110 comprises a hydroxyethyl methacrylate (HEMA) monomer, and the method comprises the step of swelling an optical element, preferably an ophthalmic device, in water, thereby obtaining a water content of 10-80% by weight, preferably 35-70% by weight, for the optical element.

[0160] In the embodiment, the polymerizable mixture 110 comprises an acrylate monomer that does not contain a HEMA monomer, and the method comprises a subsequent step of swelling an optical element, preferably an ophthalmic device, in water, thereby obtaining a water content of 10-80% by weight, preferably 35-70% by weight, for the optical element.

[0161] In the embodiment, the polymerizable mixture 110 comprises a reactive silicone precursor, and the method comprises the following step of swelling an optical element, preferably an ophthalmic device, in water, thereby obtaining a water content of 5-70% by weight, preferably 10-50% by weight, for the optical element.

[0162] Novel ophthalmic devices The methods and apparatus of the present invention enable the formation of optical elements 211 of previously unobtainable designs, such as, in non-limiting examples, one or more of the following: a contact lens or intraocular lens having a non-rotationally symmetric plane having corresponding optical corrections and including a very steep radius of curvature and very high spherical and cylindrical corrective components; a contact lens or intraocular lens having multiple spherical and cylindrical corrections within the same lens, as opposed to a single spherical correction power, and including a spherical correction power that reflects the power distribution of the eye as well as the average correction power of refractive power from a phoropter or refractometer; a contact lens or intraocular lens that can correct (by non-rotational symmetry) optical aberrations or aberrations caused by abnormal comal planes resulting from poor surgical outcomes of PRK, LASIK, or LASER surgery.

[0163] Additive manufacturing based on iterative grayscale images Referring here to Figure 3, an exemplary energy transmittance pattern, such as grayscale image 300, may be used to create an additive manufacturing control command that controls the release of droplets of polymerizable mixture with a pattern that replicates grayscale image 300.

[0164] For example, in some embodiments, a data map is used that represents, either directly or by titration, the amount of polymerizable mixture deposited at a given location corresponding to a data value associated with a pixel in the grayscale image 300, such as an integer map. In other embodiments, the pixel-related values ​​may be floating-point or other representations of real integers. The data values ​​may also correspond to the amount of energy transmittance at the pixel location, and the data values ​​may be accessed electronically, and a processor executing software commands may convert the data values ​​into additive manufacturing printhead control commands. Printhead control commands are executable for each pixel to control the deposition of the polymerizable mixture at the location corresponding to the pattern replicating the grayscale image 300. For example, a data value with a relatively large digital value may correspond to a darker region of the grayscale image 300 and may correspond to the emission of a larger amount of polymerizable mixture from the printhead than the emission corresponding to a brighter region of the grayscale image. The larger amount of polymerizable mixture results in a thicker deposition 301, and the control command value may be assigned by converting the grayscale value at the location of the thicker deposition 301 to the printhead control command value for the thicker deposition 301. Similarly, smaller values ​​in the grayscale may correspond to thinner deposition 301A, and the appropriate print head control command value may be assigned by converting the smaller grayscale value to an appropriate control command value for thinner deposition 301A.

[0165] In some examples, a thicker deposition 301 may be formed by printing a relatively large amount of polymerizable mixture at specific locations on the receiving surface during the passes of the 3D print head on the receiving surface to be printed, while a thinner deposition 301A may correspond to printing a relatively small amount of polymerizable mixture at the locations of the thinner deposition 301A. The thicker deposition 301 may correspond to the relatively dark areas of the grayscale image 300, while the thinner deposition 301A may correspond to the relatively bright areas of the grayscale image 300.

[0166] According to the present invention, following each pass of deposition of the print head and associated polymerizable mixture, the deposited polymerizable mixture may be allowed to "sit" for a short period of time, thereby modifying the surface properties of the material by physical forces such as gravity, surface tension, and microforces. Modification of surface properties may include, in non-limiting examples, one or more of the following: leveling high and low areas formed during the deposition process, smoothing the surface of the precipitated polymerizable mixture, allowing the precipitated polymerizable mixture to flow into intervening regions, and forming uniform edges of the precipitated polymerizable mixture.

[0167] Essentially, the present invention is also possible for top surfaces 302 formed by naturally occurring physical forces, as opposed to manufactured surfaces such as mold surfaces and / or turned surfaces. Gravity smooths the top surface of the deposited polymerizable mixture before it undergoes a gelling process, such as being pinned by exposure to a controlled amount of chemical radiation.

[0168] In some variations of the present invention, a control command may be used to determine how many times the 3D print head has passed over the receiving surface. The number of passes of the 3D print head may correlate with the thickness of the deposited polymerizable mixture, and may also correlate with the amount of energy transmittance at a particular location in the pattern of the deposited polymerizable mixture. In this way, the deposited polymerizable mixture may be deposited, pinned, and finally cured in a shape and volume suitable for forming an ophthalmic lens having the desired ophthalmic quality. The deposited polymerizable mixture achieves sufficient thickness and appropriate shape by applying repeated corresponding grayscale images.

[0169] In some variations of the present invention, each pass of the 3D print head may print a pattern of polymerizable mixture corresponding to the same grayscale image, while in other embodiments, different passes of the 3D print head may correspond to different grayscale images than the previous pass. As described above, in some variations of the present invention, each pass of the 3D print head depositing the polymerizable mixture may be followed by exposure of the polymerizable mixture to a gelling process, such as chemical radiation or thermal activation, in an amount sufficient to partially polymerize the deposited polymerizable mixture. The curing process may be completed after the final pass of the polymerizable mixture is complete. In various embodiments, the final layer may be exposed to a pinning step and / or move directly to the entire curing process.

[0170] Curing and / or pinning may be facilitated by the inclusion of one or more photoinitiators in the deposited monomer. The photoinitiators may include, as non-limiting examples, initiators activated by energies of about 392 nM and 400 nM.

[0171] In some embodiments, the energy transmittance pattern (e.g., a grayscale image) may be derived from a molded product in physical form, processed through an optical scanning process, an image acquisition process, or a photography process, and the energy transmittance data may be captured in an electronic form, such as a digital data value, which may then be converted into a control command.

[0172] Some variations of the present invention generally involve a spherical grayscale image, where smaller values ​​correspond to thicker sediments. Thus, different conversion protocols may be assigned to different grayscale images depending on which values ​​correspond to thicker and thinner sediments, respectively.

[0173] In some examples, a single grayscale image may be used to represent the desired product lens and its associated control commands. The single grayscale image may be repeatedly deposited in a series of passes of a 3D print head until the desired optical quality is embodied in the deposited polymerizable mixture, forming a molded product that also satisfies the physical parameters suitable for being fitted into a patient's eye after curing.

[0174] In other examples, a series of grayscale images may be assembled to create a set of control commands. These control commands may result in the deposition of different shape designs, physically creating an additive composite of images. In other examples, multiple grayscale images may be combined and processed before any processing occurs. In some embodiments, the combination of multiple images may be normalized to correspond to upper and lower thickness coefficients.

[0175] In some embodiments, different feature areas, such as edge profiles 303, alignment feature areas, etc., may be programmed into the optical element command protocol by adding a grayscale image to the lens profile.

[0176] In some examples, refractive elements may be designed as an array of grayscale values ​​at the position of the surface plane, where the values ​​correspond to the thickness or range of thickness added during the printing process. In similar examples, a certain grayscale value may correspond to a plano-lens element that does not add refractive power to any base structure.

[0177] In some examples, grayscale images may be referenced from a number of file types, such as one or more of jpeg, tiff, bmp, png, etc., as non-limiting examples, and may be used to create control command protocols for printing desired molded parts, such as ophthalmic lens molded parts, so as to result in the deposition of more polymerizable mixture in areas where a thicker deposition is targeted, by varying the amount of polymerizable mixture deposited at random locations. Printing the entire pattern may result in a molded part without intervening regions.

[0178] In some variations of the present invention, a grayscale image or an additional combination of images may correspond to the processing of multiple separate passes of a 3D print head, and the amount of polymerizable mixture deposited at a particular location is subjected to a pinning step before the next deposition pass is completed. The polymerizable mixture deposited between passes of the printing process may be a monomer mixture having various photoinitiators. One of the photoinitiators may be related to the wavelength of chemical radiation during the relevant pinning step. After multiple printing passes have been processed, the entire volume of polymerizable mixture deposited on the receiving substrate may be subjected to a curing step. In some examples, the curing step may involve exposure to chemical radiation of different wavelengths and exposure times, intensities, etc.

[0179] In other embodiments, in some embodiments, a grayscale or energy transmittance pattern may be dithered via a dithering process or algorithm before the generation of control commands for the print head based on the grayscale or energy transmittance pattern, in order to produce a smoother image deposited through the evacuation of droplets from the print head and accumulation before curing. The dithering may include, as a non-limiting example, a process consistent with Floyd-Steinberg, Burkes, Sierra, Two Row Sierra, Jarvis, Stevenson, Arce, or other processes.

[0180] Referring next to Figure 4, the optical element 400 is shown in several embodiments of the present invention. The optical element 400 includes a peripheral portion 401, which may be printed or otherwise formed in front of the optical zone portion 402 of the optical element 400. A lens carrier portion 403 may transition between the optical zone portion 402 and the peripheral portion 401. The carrier portion 403 is preferably of a size and shape suitable for comfortably maintaining the finished lens in a predetermined position in the wearer's eye. During the additive manufacturing of the optical element 400, the polymerizable mixture contained in the peripheral portion 401 may be deposited and pinned before the polymerizable mixture contained in the optical zone portion 402 is printed and pinned, but not fully polymerized. In some preferred embodiments, the peripheral portion 401 may contain a larger mass so that, as the polymerizable mixture cures into a polymer, the stresses arising from the polymerization process do not deform the optical zone portion 402 due to the stabilizing effect of the larger mass of the peripheral portion 401.

[0181] In some embodiments, the peripheral portion 401 may remain with the optical element 400 to form a pleasing edge feature. In other embodiments, part or all of the peripheral portion 401 may be removed, for example, by laser trimming.

[0182] Embodiments including a larger mass peripheral zone portion 401 may be formed via the following steps: a) printing or otherwise depositing a polymerizable mixture onto the peripheral zone portion (which has an annular shape as a whole in the case of a spherical lens, and in the case of other lenses, has a corresponding peripheral shape such as an egg shape or an almond shape); b) pinning the polymerizable mixture onto the peripheral zone portion 401, which is preferably done after each pass of the print head that deposits the monomers; c) printing or depositing the polymerizable mixture onto the optical zone; pinning the polymerizable mixture onto the optical zone; and curing the deposited polymerizable mixture. Some embodiments may further include placing a cap on the optical zone to provide optical quality.

[0183] Next, referring to Figure 5, this is a side section view showing the optical insertion portion or cap 504 and the peripheral portion 501 and carrier portion 502 that support the optical zone 503. In some embodiments of the present invention, the peripheral portion 501 may contain a greater mass than the carrier portion 502 and / or optical zone 503 portion of the lens 500.

[0184] Generation of axial thickness profile Water-containing contact lens front surface radius (R F ) are the lens power in air (P), lens refractive index (n), center thickness (CT), and rear surface radius of curvature (R). B It is produced from a thick lens formula using ).

[0185] The formula for thick lenses may include, as an unrestricted example, the following: The effective focal length of a thick lens with respect to its principal plane is given by:

[0186]

number

[0187] The distance from the vertex of the lens to the principal plane is

[0188]

number

[0189] In the case of ophthalmic lenses, the example variables may include the following:

[0190]

number

[0191] The front and rear optical zone surfaces may be generated from the front and rear radii of curvature of the spectacle lens and the central thickness of other optical elements.

[0192] An exemplary surface is shown in Figure 6 for a -3.0D design with a central thickness of 0.1008 mm, a back radius of curvature of 9.1 mm, and a refractive index of 1.4055.

[0193] In some embodiments, the axial thickness profile may be generated by subtracting the rear surface position from the front surface position for multiple radial positions.

[0194] The ratio of water-containing lenses to non-water-containing lenses may vary depending on the lens material, with the water-containing lenses being 1.4 times larger in each direction than the non-water-containing lenses. Therefore, the axial thickness profile of the non-water-containing lens may be about 1.4 times smaller than the axial thickness profile produced from the front and rear surfaces of the water-containing lens (wherein used, the term "about" may be within 10% of the stated amount). Also, the radial position may be about 1.4 times smaller than that of the non-water-containing lens.

[0195] Next, referring to Figure 6, a graphical representation 600 of the anterior curved surface 603 and posterior curved surface 604 of the optical zone of the hydrous ophthalmic lens is shown.

[0196] The graph representation 600 includes a first axis having a scale for the water-containing surface position 601 and a second axis having a scale for the water-containing radial position 602. The first curve maps the values ​​of the anterior curve 603 of the ophthalmic lens optical zone, and the second curve maps the values ​​of the posterior curve 604.

[0197] Referring next to Figure 7, a graphical representation 700 of the axial thickness profile 703 of the optical zone of a non-hydrated ophthalmic lens is shown. In a preferred embodiment, the axial thickness profile may be adequately described by an even-degree quartic polynomial. Coefficients from this model may be referenced to generate the optical zone portion of a grayscale printed pattern, or other energy transmittance or energy intensity map patterns.

[0198] The graph representation 700 includes a first axis with a scale of non-water-containing axial thickness 701 and a second axis with a scale of non-water-containing radius position 702. The curve maps the axial thickness 703 value of the ophthalmic lens optical zone, and the numerical value correlated with the thickness 704 is displayed in the center of the graph representation 700.

[0199] In astigmatism lenses, the optical power differs for different directions (meridians) within the optical zone. For example, -2.75D / -4.5DX90 has a power of -2.75D in the vertical direction and -7.5D in the horizontal direction. The resulting axial thickness profile changes in the meridian direction within the optical zone, being "flattest" in the vertical direction and "steepest" in the horizontal direction.

[0200] Referring now to Figure 8, a false-color image of the thickness profile 800 is shown for the optical zone, where "the first intensity 801 represents a small thickness, and the fourth intensity 804 represents a region with a relatively large thickness. One or more intermediate thicknesses 802-803, such as the first intermediate thickness 802 and the second intermediate thickness 803, may also be included. Each thickness is achieved by depositing an appropriate amount of polymerizable mixture at the respective positions indicated by the thickness profile 800, which may allow the polymerizable mixture to settle, pin the settled polymerizable mixture in place via a gelation process, and finally cure the deposited and pinned polymerizable mixture."

[0201] The horizontal (most negative degree) and vertical (most positive degree) axial thickness profiles may be modeled by even quartic polynomials and used as coefficients to generate an optical zone grayscale print pattern represented by a thickness profile of 800.

[0202] Energy transmittance printing pattern generation In some embodiments, the energy transmittance print pattern (which may be a grayscale print pattern or other representation of energy intensity) may include two or more regions: optical zones 801-804 (defined exemplary by the axial thickness profile): and a periphery 805. It may also include other regions, such as regions containing pharmaceuticals or other elutable substances. Each region may be defined in various ways. For example, in a non-limiting example, the pixel size of the print pattern may be specified as approximately 0.021 mm. The diameter of the non-water-containing lens may be, for example, 10.0 mm. The number of pixels in the X and Y directions is defined by the following relationship:

[0203]

number

[0204] This definition is M pixels Ensure that the number is odd and that the center of the lens is in the center of the printed pattern.

[0205] For example, many grayscale levels may be specified, such as an 8-bit (255 gray levels) print pattern. Changing both of these values, which may affect the quality of the printed lens, is within the scope of the present invention.

[0206] spherical surface A spherical lens generally contains an optical zone that is rotationally symmetric (within 10% of the symmetry), and may be defined, for example, by using the thickness of the center of a non-water-containing lens and coefficients from an even-order quartic model:

[0207]

number

[0208] Here (x0, y x The print pattern is the primary feature. Other variations are also within the scope of this invention.

[0209] The center thickness (CT) used to generate the thickness profile may be based on the water content thickness multiplied by the number of layers to be printed. Therefore, if the water content lens CT is 0.120 mm, the number of layers to be printed is 6, and the layer thickness is 0.012 mm, the CT used to generate the print pattern is 0.120 mm - 0.72 mm = 0.048 mm.

[0210] In some preferred embodiments, this may be done to ensure that the ratio of the "brightest" pixels to the "darkest" pixels in the pattern remains within a print-acceptable range. In other embodiments, the image may be converted to a binary image by print head controller software. If the grayscale range is too large, the "bright" areas may not have enough "dark" pixels to form a smooth lens surface.

[0211] The thickness is defined as the half-diameter (r) of the non-hydrated optical zone. max ), or typically, calculations may be performed for pixels smaller than 4.0 mm / 1.4 (~2.857 mm).

[0212] The periphery 805 is the region where r(mm) is outside the optical zones 801-804 but within the lens diameter. Many different methods may be used to define the thickness profile of the periphery. For example, in some preferred embodiments, the pattern uses the thickness at the edge of the optical zone for all pixels of the periphery. Alternative methods may include one or more of the following: linearly tapering the thickness from a value at the optical edge to a value defined at the lens “edge”; and tapering the thickness from a value at the optical edge to a value defined at the lens “edge” using a higher-order polynomial or conical cross section; adding a “reinforcement” ring to the periphery to improve lens handling; tapering using different methods in different zones of the periphery; and a combination of tapering and a “reinforcement” ring.

[0213] Toric (lenses for astigmatism) The optical zone does not have to be rotationally symmetric and may be defined using the thickness of the non-water-containing lens center, two sets of coefficients from an even-order quartic model of the most positive and most negative meridians, and a desired angle in the printed pattern of the most positive meridian.

[0214] For example, in some embodiments, the print pattern is generated by calculating an "effective" quadratic coefficient for each principal meridian:

[0215]

number

[0216] The "equivalent" r² coefficient is defined as the average of the two effective coefficients. The astigmatism coefficient is defined as follows:

[0217]

number

[0218] Here, C 2,effective,plus This is the effective second coefficient of the most positive meridian, C 2,effective,minus This is the effective second coefficient of the most negative meridian. For each pixel of the lens print pattern, the distance from the lens center (r(x,y)) and the angle in standard Cartesian coordinates (θ(x,y)) are calculated.

[0219] The thickness of the optical zone may be defined as follows:

[0220]

number

[0221] Here, φ is the angle of the most positive meridian.

[0222] The thickness at the edges of the optical zone varies with angle. For toric printed patterns, the transition zone may be generated to provide a single thickness value for all angles. The transition zone may be an annular shape with a width of 0.5 mm for water-containing lenses (0.5 mm / 1.4 for non-water-containing lenses). The target thickness for the transition may be equal to the minimum thickness at the boundary of the optical zone, or essentially equal to the following:

[0223]

number

[0224] The thickness of each pixel in the transition region is defined as a linear function of its radial position. The thickness at the optical zone edge is defined for each pixel in the transition region as follows:

[0225]

number

[0226] The slope of each point is defined as follows:

[0227]

number

[0228] The intercepts of each point are defined as follows:

[0229]

number

[0230] The thickness of each point in the transition region is defined as follows:

[0231]

number

[0232] Next, referring to Figure 9, an exemplary graph image of the transition region is shown. The peripheral axial thickness profile 900 is defined by a linear change from the edge of the transition zone 904 to the minimum axial thickness of the optical zone 901. The slope and intercept of the peripheral points 902-903 are defined in the same manner as used to define the transition zone, except that the edges and minimum thickness of the transition zone are used for the edges of the thickness of the optical zone and the thickness of the transition zone, respectively. All pixels outside the lens diameter may be set to 0. Figure 10 shows the thickness profile of the peripheral region 1000 of an ophthalmic lens having multiple different thicknesses 1002-1004 in the peripheral region of the optical zone 1001. Figure 11 shows the thickness profile of a complete ophthalmic lens 1100. The shown thickness profile includes lens portions 1101-1105, which include optical zones 1101-1104 and a peripheral region 1105. Each of the lens portions 1101-1105 contains one or more pixels 1106 (shown in the magnified view). Each pixel 1106 may be associated with a thickness.

[0233] Print pattern

[0234] In some embodiments of the energy transmittance pattern (e.g., energy intensity pattern or grayscale pattern) corresponding to the printed pattern, “bright” pixels may represent unprinted areas, and “dark” pixels may represent areas that receive the deposited polymerizable mixture. The “intensity” of the “dark” pixels corresponds to the desired thickness of the resulting ophthalmic lens at that location.

[0235] In some exemplary embodiments, the "intensity" of the lens print pattern may be defined as follows:

[0236]

number

[0237] Here, floor() converts the value to the smallest integer.

[0238] All pixels outside the lens may be set to 255, with smaller intensity values ​​corresponding to greater thickness, and the minimum value corresponding to the minimum thickness.

[0239] A value of 255 corresponds to an 8-bit image. If more than 255 gray levels are used, the value 255 is replaced with the number of gray levels. For example, for a 10-bit image, the value would be 1023.

[0240] Referring now to Figure 12, the method steps for forming an ophthalmic lens according to several embodiments of the present disclosure are shown in flowchart form.

[0241] In step 1202, the method includes positioning a substrate in a first position relative to an additive manufacturing print head. The substrate may include a receiving portion, which may be planar or curved. The receiving portion may act as a receiving surface for a first pass of the print head for depositing the polymerizable mixture. After the first pass, the receiving surface will typically include at least several areas having the previously deposited polymerizable mixture.

[0242] In step 1204, the method may include releasing a first pattern of deposited droplets of polymerizable mixture from the print head, the pattern of deposited droplets of polymerizable mixture corresponding to a first portion of the energy transmittance map of the ophthalmic lens being formed. Preferably, the pattern is a two-dimensional image representing the light intensity passing through the desired optical system. The droplets are released at a time specification such as T1, which may be relative to other time specifications. In a preferred embodiment, the two-dimensional representation will have numerical values ​​associated with X,Y positions (or other coordinate specifications). The numerical values ​​will represent the amount of light passing through the optical element at the positions specified by the X,Y axis specifications. In some embodiments, the print pattern may be numerically based such that the amount of polymerizable mixture deposited at positions on the receiving surface corresponding to the X,Y pattern correlates with the numerical values ​​(for example, brighter areas will have lower X,Y numerical values ​​and receive less polymerizable mixture, and darker areas will have higher X,Y numerical values ​​and receive more polymerizable mixture).

[0243] The design of the optical element may be achieved by analyzing the radiation tracing pattern of how light passes through the optical element. In some embodiments, the X,Y values ​​may be derived from a mathematical model of the three-dimensional shape of the desired optical element.

[0244] In step 1206, the method may include receiving droplets of the deposited polymerizable mixture on a receiving surface, the receiving surface may include one or more of a substrate, an aggregate of polymerizable mixture formed from previously released droplets of polymerizable mixture, and an insertion part. The insertion part may include, for example, an optical insertion part, a passive electronic device, an active electronic device, and / or a power source such as a battery, a harvesting device, or an antenna.

[0245] In step 1208, at a second time (T2), the deposited droplets of polymerizable mixture on the receiving surface may be subjected to a pinning step. The pinning step will cause partial polymerization of the deposited droplets of polymerizable mixture. Preferably, the partial polymerization will result in viscous aggregation of the partially polymerized mixture, which is resistant to flow but may integrate with the subsequently deposited polymerizable mixture.

[0246] In step 1210, the method may include repositioning the substrate (and the deposited polymerizable mixture) to the following position (position plus N) relative to the print head.

[0247] In step 1212, the method may include releasing a following pattern of deposited droplets of a polymerizable mixture corresponding to the following portion of the energy transmittance map of the article to be formed, for example, an ophthalmic lens to be formed.

[0248] In various embodiments of the present invention, the method may include repeating the steps multiple times. For example, there may be multiple passes of the print head over the substrate and multiple residence times, during which gravity acts on at least a portion of the deposited droplets of polymerizable mixture to smooth the surface of the deposited polymerizable mixture, fill the intervening spaces between the deposited droplets, and allow aggregation of the already deposited and pinned material with the deposited material. Thus, in step 1214, the next pattern of droplets of polymerizable material may be released. The pattern may be the same as the previous pattern or a different pattern.

[0249] In step 1218, the polymerizable material deposited in the current pass of the print head may be integrated with a material on the receiving surface, such as a previously deposited material. In some embodiments, the integrated material may form a single volume portion of the polymerizable mixture on the substrate.

[0250] In step 1220, gravity may act on at least a portion of the deposited droplets of the polymeric mixture to smooth the surface of the deposited polymeric mixture, fill the intervening spaces between the deposited droplets, and agglomerate the deposited material with the already deposited and pinned material.

[0251] In step 1222, the method may include curing the droplets of the deposited polymeric mixture.

[0252] In some embodiments, the pinning step may include exposing the deposited droplets of the polymeric mixture to a first wavelength of actinic radiation for a limited time sufficient for the deposited droplets of the polymeric mixture to gel without causing curing of the deposited droplets of the polymeric mixture. Similarly, in some embodiments, the curing step may include exposing the deposited polymeric mixture to actinic radiation of a second wavelength for a time and intensity sufficient to cause polymerization of the deposited droplets of the polymeric mixture. Some embodiments may also include promoting the curing step by an increase in ambient temperature.

[0253] Referring now to FIG. 13, the schematic shows the deposition of one or more polymeric mixtures 1302 from one or more print heads 1301 to form an ophthalmic lens 1307. The print head 1301 deposits the polymeric mixture 1302 until a volume portion of the polymeric mixture 1303 is formed on the receiving area 1306 of the substrate 1305, in a pattern that replicates a 2D pattern used to generate control commands for each pass of the print head 1301 relative to the position of the substrate 1305. At least a portion of the receiving area 1306 of the substrate 1305 will act as the receiving surface of the deposited polymeric mixture 1302 until the volume portion of the deposited polymeric mixture 1303 covers the footprint area for the design of the ophthalmic lens 1307.

[0254] As described herein, in some preferred embodiments of the optical element, the amount of the polymeric mixture 1302 deposited from the print head 1301 to form the ophthalmic lens 1307 varies according to a two-dimensional pattern representing an integer map of the energy intensity, which may represent the transmittance of energy through the ophthalmic lens.

[0255] The pattern is preferably a two-dimensional image representing the light intensity through the desired ophthalmic lens 1307. In a preferred embodiment, the two-dimensional representation will have respective numerical values associated with a plurality of X, Y positions. The numerical values may represent the amount of light passing through the ophthalmic lens 1307 at a given position specified by the X, Y axis designations.

[0256] The control commands to the print head cause the print head 1301 to deposit the polymeric mixture 1302 based on a two-dimensional print pattern that specifies the amount of the polymeric mixture 1302 to be deposited at a given X, Y position. After a plurality of successive passes of depositing the polymeric mixture 1302, the volume portion of the polymeric mixture 1303 on the substrate 1305 has a three-dimensional shape representative of the mathematical model of the desired ophthalmic lens.

[0257] The two-dimensional print pattern of the amount of the polymeric mixture representing the amount of light passing through the ophthalmic lens 1307 at a given position specified by the X, Y axis designations may also correlate with the amount of the polymeric mixture 1302 deposited at a position on the receiving surface 1304 (e.g., brighter regions of the two-dimensional print pattern may have lower X, Y numerical values and receive less polymeric mixture, and darker regions may have higher X, Y numerical values and receive more polymeric mixture).

[0258] In some embodiments, the design of the ophthalmic lens may be achieved by analysis of a ray tracing pattern of how light passes through the ophthalmic lens. Preferably, the X, Y numerical values may instead be derived from a mathematical model of the three-dimensional shape of the desired ophthalmic lens.

[0259] According to the present invention, a two-dimensional printed pattern that identifies the amount of polymerizable mixture deposited at a given X,Y position is printed multiple times in a series of passes of the print head onto the substrate 1305. The deposited polymerizable mixture 1302 is received on a receiving surface 1304. The receiving surface 1304 may include either or both the volume portion of the previously deposited polymerizable mixture 1303 and the receiving area 1306 of the substrate 1305.

[0260] The deposited polymerizable mixture 1303 undergoes a pinning and / or gelling process to form a volume of gelled polymerizable mixture 1303. The volume of gelled polymerizable mixture 1303 prevents (or at least substantially slows down) the migration of the polymerizable mixture that has been sufficiently polymerized and received on the receiving surface, while allowing the subsequently deposited polymerizable mixture 1302 to melt with the previously deposited (and pinned) volume of polymerizable mixture 1303 to form a structure having a single mass of polymerizable mixture. In a preferred embodiment, the melting includes mixing with, or becoming mixed with, the previously deposited and pinned volume of polymerizable mixture 1303, so that when the volume of polymerizable mixture 1303 hardens, individual layers or streaks of deposited polymerizable mixture 1302 are no longer distinguishable in the volume of polymerizable mixture 1303 formed on the receiving area 1306 of the substrate 1305. Such embodiments may be preferable because unwanted diffraction may be optical quality resulting from consecutive steps or other interlayer artifacts related to the presence of separate layers of polymerized material in the ophthalmic lens.

[0261] Prior to pinning, gravity may act on the surface 1304 of the polymerizable mixture 1303 to smooth the surface 1304, fill in surface aberrations, and thereby improve the optical quality of the resulting ophthalmic device (compared to a lens formed from a machined lens surface and / or a lens formed from a machined mold part).

[0262] Curing of the volume portion of polymerizable mixture 1303 follows the placement of droplet polymerizable mixture 1302 between the print head 1301 and the substrate 1305 in the final pass. Curing may be treated by exposing the volume portion of polymerizable mixture 1303 to sufficient chemical radiation and / or heat to cause substantially complete polymerization of the volume portion of polymerizable mixture 1303.

[0263] As shown, Figure 13 shows a print head 1301 substantially perpendicular to the apex 1308 of the deposited polymerizable mixture 1303. In various embodiments, the droplet polymerizable mixture 1302 may (or may not) follow a trajectory perpendicular to the apex 1308 of the receiving surface, which may include one or more of the substrate 1305, the receiving area 1306, and the surface of the previously deposited polymerizable mixture 1303.

[0264] Referring here to Figure 13A, a print head 1301 is shown moving in the direction 1309 of the printing path. The droplet of polymerizable mixture 1302A will follow a droplet trajectory 1309 that is influenced by the velocity and direction of the print head 1301 at the time of droplet release of polymerizable mixture 1302A. The droplet trajectory 1309 will have its own velocity and direction. According to the present invention, in some embodiments, the print head 1301 and the droplet trajectory 1309 may be at angles other than perpendicular to the surface of the apex of the receiving surface 1304, because a portion (e.g., the majority) of the droplet of polymerizable mixture 1302A will be integrated with the previously deposited polymerizable mixture 1303A, pinned, and ultimately cured. Thus, this process differs from conventionally known processes that require small portions of additive material to be gradually placed on the surface and not integrated with the previously deposited material before curing.

[0265] Referring next to Figure 14, exemplary dynamic shapes of polymerizable mixture droplets 1401 are shown at various time points 1402 after ejection from the print head. According to the present invention, the shape of droplet 1401 may change based on the speed of movement of droplet 1401 through the ambient atmosphere. In some preferred embodiments, the articles formed by the processes disclosed herein are generally unaffected by the shape of the polymerizable material droplets 1401. The relatively small mass of each droplet 1401 and the integration of the droplet with other polymerizable material on the receiving surface prevent the shape of the manufactured article from being affected, essentially, by the shape of individual droplets 1401 or the changing shape of droplets 1401 at various time points 1402 after ejection from the print head (not shown in Figure 14).

[0266] Referring now to Figure 15, flowchart 1500 shows exemplary method steps that may be performed in some embodiments of the present invention.

[0267] In step 1501, the process may include positioning the substrate at a first position relative to the additive manufacturing print head.

[0268] In step 1502, the process may include releasing a first pattern of deposited droplets of polymerizable mixture from the print head, the first pattern of deposited droplets of polymerizable mixture corresponding to a first portion of a grayscale image.

[0269] In step 1503, the process may include receiving deposited droplets of polymerizable mixture on a receiving surface, the receiving surface may include one or more of the substrate, the previously released droplets of polymerizable mixture, and the inserted molded article. The inserted molded article may include, in non-limiting examples, one or more of the optical elements such as rigid transparent lenses, electronic devices, and power supplies.

[0270] In step 1504, the process may include repositioning the substrate to the next position relative to the print head. The repositioning may include moving one or both of the substrate and the print head relative to the other.

[0271] In step 1505, the process may include discharging the next pattern of deposited droplets of the polymerizable mixture from the print head corresponding to the next portion of the grayscale image.

[0272] In step 1506, the process may include enabling a physical force such as gravity to act on the deposited droplets of the polymerizable mixture.

[0273] In step 1507, the process may include integrating at least some of the droplets to form a bonded volume of the polymerizable mixture on the substrate.

[0274] In step 1508, the process may include exposing the deposited droplets of the polymerizable mixture on the receiving surface to a pinning process that causes partial polymerization of the deposited droplets of the polymerizable mixture.

[0275] In step 1509, the process may include repeating the positioning and deposition steps for a plurality of passes of the print head relative to the substrate.

[0276] In step 1510, the process may include curing the bonded volume of the polymerizable mixture to form an ophthalmic lens.

[0277] The process may include, following each pass of the print head relative to the substrate, integrating at least some of the droplets of the polymerizable mixture deposited during the current pass with the polymerizable mixture previously deposited on the receiving surface to form a bonded volume of the polymerizable mixture on the substrate.

[0278] In step 1511, the process may include releasing the formed ophthalmic lens from the substrate.

[0279] Experiment details Method for determining the water content of a hydrogel device

[0280] The water content of hydrogel devices (e.g., contact lenses) may be determined as described below: Section 4.6 of ISO / DIS 18369-4:2016 (gravimetric methods shown in 4.6.2).

[0281] Keratometry measurement The goniometer measures the central radius of the cornea, and in this case, the central radius of the front surface of the non-hydrated hydrogel component formed on the PMMA dome (see the Experiment section on 3-D printing on PMMA domes). The instrument used was an automated corneal analyzer from the Nidek Model ARK900S. The support was set on a horizontal stand, and a wedge was added to align the center and axis of the PMMA dome with the hydrogel surface with the center and axis of the corneal analyzer. In the first set of measurements, where astigmatism was large, the wedge was not used, and the measured astigmatism was an artifact due to the measurement being performed off-axis.

[0282] Curvature radius measurement The power of a contact lens depends on a combination of the powers of the front and back surfaces of the contact lens, which are modulated by the refractive index of the material and the thickness of the contact lens. The powers of the front and back surfaces of the contact lens depend on the radius of these surfaces.

[0283] The relationship between power and radius in air is given by power = (contact lens refractive index - 1) / radius, where power is expressed in diopters and radius in meters.

[0284] For the front surface, the radius is defined in ISO 18369-1:2006 (E) (2.1.2.2.5) as the radius of curvature of the front optical zone of a surface having a single refractive element.

[0285] The front radius of curvature of the PMMA dome was measured using an automated corneal meter, also known as an ophthalmometer, one of the methods specified in ISO DIS 18369-3:2016 (Annex C). The ophthalmometer method measures the size of the reflected image of a target placed at a known distance in front of the hard or soft lens surface, and then the relationship between the curvature of the reflected image and the magnification is used to determine the radius of the back optical zone. Nevertheless, this method was used to measure the front radius of the PMMA dome.

[0286] light transmittance Light transmittance is defined in ISO 18369-1:2006(E). The light transmittance values ​​shown in the table below represent the average values ​​from 380nm to 780nm. The measurement method is described in detail in ISO DIS18369-3:2106(4,8.2).

[0287] Equipment and materials A series of experiments were conducted to demonstrate the principle of the present invention. The experiments were performed using the following:

[0288] raw materials 2-Hydroxyethyl methacrylate (HEMA); 99.9% HEMA with 16 ppm MEHQ, Ethylene glycol dimethacrylate (EGDMA); Assay: 98.0% Methacrylic acid (MAA); assay 99.0% Trimethylolpropane trimethacrylate (TMPTMA), technical grade Irgacure 651 photoinitiator, from BASF Corp, Southfield, MI. Irgacure 819 photoinitiator, from BASF Corp, Southfield, MI. Glass microscope slides, from EMS, Hatfield, Pa, and Am Scope. Tween80 (Polysorbate 80) Surfactant Reagent-grade isopropanol Deionized or distilled water Sterile saline solution, Walgreens or B&L Nitrogen gas cylinders (<0.1% oxygen) and / or liquid nitrogen tanks RotoBap, glove bag, desiccator, brown bottle, syringe, 5pm filter, lint-free towel, standard beaker, weighing scale (0.001g accuracy), vacuum pump LED sources and measuring instruments OMNI lamps with 365nm and 400nm output. Omnicure LM 2011 Light Meter for Intensity Measurement Honeywell Toxi Pro 544590VD Portable Gas Oxygen Monitor A gauge that reads oxygen levels below 33 millibars (3.3 kilopascals).

[0289] 3D printing station a) A Fujifilm Samba printhead, b) a conveyor belt that moves the material beneath the printhead, and two different chemical radiation sources in the form of UV lamps were custom-built. The entire printing station is housed in an atmospheric pressure enclosure with gas ports.

[0290] Example Series A - Preparation of Model Samples In this series, uniformly thick, square samples (10 mm × 10 mm) of polymerized HEMA were prepared and evaluated.

[0291] Preparation of substrates Three drops of Tween80 were added to 20 ml of reagent-grade isopropanol and filtered through a 3.1 μm filter. A glass slide was immersed in this solution three times and air-dried.

[0292] Preparation of aqueous solutions Five drops of Tween80 were mixed with 100 mL of deionized water and heated to 80-90°C.

[0293] PM-1A, PM-1B, and PM-1C: HEMA:97. EGDMA: 1.6% Irgacure 819: 0.2% Irgacure 651: 0.5%

[0294] PM-2: HEMA: 98.1% EGDMA: 1.2% Irgacure 819; 0.2% Irgacure 651; 0.5%

[0295] PM-3A, PM-3B and PM-3C

[0296] Uncatalyzed polymerization mixture samples (PM-1A, PM-1B, PM-1C, PM-2, PM-3A, PM-3B, and PM-3C; see above) were prepared by mixing monomers and crosslinking agents in brown bottles and left overnight in a refrigerator. The final polymerization mixture samples were treated with a photoinitiator in a rotovap using alternating degassing and nitrogen blankets. The sample volume was approximately 120 grams for each of PM-1A, PM-1B, PM-1C, and PM-2. The same volume was approximately 34.5 grams for each of PM-3A, PM-3B, and PM-3C.

[0297] The partial pressures corresponding to the oxygen concentration in the polymer mixture are as follows: PM-1A: <0.5% O2 PM-1B: 2.0% O2 PM-1C: 5.0% O2 PM-2: <0.5% O2 PM-3A: <0.5% 02 PM-3B: 2.0% 02 PM-3C: 8.5% 02

[0298] O2 concentration of <0.5% O2 A 120g sample was processed using Rotovap according to the following protocol, by alternating between degassing to 11.0–12.0 torr (approximately 14.0 mbar) and nitrogen blanketing at 760 torr (1013 mbar) for 3–4 cycles. Each degassing cycle ranged from 5–20 minutes, and each blanketing cycle did not exceed 5 minutes.

[0299] O2 concentration of 2.0% O2 A 120g sample was treated to 2.0% O2 by degassing to 72 torr (95 mbar) and blanketing with nitrogen to 760 torr (1013 mbar) according to the following protocol. The degassing cycle did not exceed 49 minutes, and the blanketing cycle did not exceed 15 minutes.

[0300] O2 concentration of 5.0% O2 A 120g sample was treated to 5.0% O2 by degassing to 179 torr (235 mbar) using the following protocol by Rotovap, followed by mixing for 45 minutes, and then blanketing with 760 torr (1013 mbar) nitrogen for no more than 5 minutes.

[0301] O2 concentration of 8.0% O2 A 120g sample was treated to 8.5% O2 by degassing to 300 torr (400 mbar) using the following protocol by Rotovap, followed by 45 minutes of mixing, and then blanketed with 760 torr (1013 mbar) nitrogen for a period not exceeding 15 minutes.

[0302] LED source and print station settings The 400nm omni-lamp was positioned 22.0mm from the substrate, and its intensity was set to 4.5W / cm2, as measured by a photometer at the substrate location.

[0303] The 365nm omni-lamp was set 123mm from the substrate, and its intensity was set to 0.63 W / cm² as measured by a photometer. The belt speed for moving the substrate from the printing station to the UV station was set to 40 ft / min (12 m / min).

[0304] A 10mm x 10mm square design was printed on a polymerizable mixture. UV pinning or gelling (stripe / sticky to the touch) occurred after 30 seconds of exposure to a 400nm lamp (3 cycles of 10 seconds each). The measured layer thickness was approximately 24μm. Several experiments were performed with different intensity settings and exposure times to select conditions.

[0305] 3D printing conditions: For UV pinning, layers were printed at 2400 dpi and exposed to a 400 nm lamp for 30 seconds, a process repeated six times. Subsequently, the pinned or gelled samples were exposed to a 365 nm lamp for 120 seconds to cure the samples.

[0306] Oxygen concentration was measured by two oxygen probes, one placed near the printing station and the other near the UV station. Oxygen control was achieved by controlling separate flows of mixed air and nitrogen before they entered the processing chamber.

[0307] result The cross-section was prepared by cutting the center of a hydrated sample, printed on a glass microscope slide, using two stacked No. 23 surgical blades. The 400-micron wide cut was then placed horizontally in a petri dish of 0.9% saline solution and subjected to equilibration for 1 hour, after which its shape was observed under a microscope.

[0308] Non-uniformity or stress can be seen as a deviation from the intended shape, which in this case is flat.

[0309] Non-uniformity or stress will adversely affect the optical properties of the material.

[0310] The appearance and tackiness of the non-hydrated samples (after curing at 365 nm) were evaluated by visual inspection and tactile sensation, respectively.

[0311] The light transmittance values ​​of the hydrated hydrogel sample (10 mm × 10 mm) prepared as described above, and the values ​​of a commercially available ACUVUE 2 contact lens (transmittance 96.83%), were calculated as an average from 380 nm to 780 nm for reference. See the table below.

[0312] The central thickness of the water-containing sample was measured optically using a cross-sectional microscope.

[0313] Evaluation of hydrated hydrogel samples

[0314] [Table 1]

[0315] [Table 2]

[0316] [Table 3]

[0317] [Table 4]

[0318] The oxygen level in the processing atmosphere affects the formed molded product. While the light transmittance of hydrated samples is important for optical function, it is quite high at low oxygen levels in the processing atmosphere (0.1%, 0.5%, 1.0%), comparable to that of commercially available contact lenses. At 2.0% oxygen in the processing atmosphere, light transmittance decreases, and at 5.0%, there is a significant decrease in light transmittance. Similarly, cross-sectional views of hydrated samples show that the lowest levels of deformation are obtained at low oxygen levels in the processing atmosphere.

[0319] The oxygen level of the polymerizable mixture has some effect on light transmittance, but oxygen up to 5.0% is acceptable if the oxygen level of the processing atmosphere is low. The cross-section of the hydrated sample shows the lowest levels of deformation at 2.0% and 5.0% oxygen in the polymerizable mixture, combined with the low oxygen level of the processing atmosphere.

[0320] The low level of deformation observed in the cross-sectional sample suggests that the product is uniform and suitable for optical applications.

[0321] For samples prepared with polymerization mixtures PM-3A, PM-3B, and PM-3C, observations were made based on touch after six layers were printed and pinned without curing.

[0322] The oxygen concentration in the atmosphere was maintained at <0.5 volume percent and measured by oxygen probes placed in close proximity to both the printing and pinning stations. Oxygen concentration control was achieved by a flow meter connected to a nitrogen tank.

[0323] result PM-3A with <0.5% oxygen: Slightly tacky but not stringy.

[0324] PM-3B with 2.0% oxygen: Slightly sticky but does not form strings.

[0325] PM-3C with 8.5% oxygen: Slightly sticky but does not form strings.

[0326] Example Series B: Preparation of hydrogel surfaces on a PMMA dome In this series, dome-shaped samples with varying thicknesses of polymerized HEMA were prepared and evaluated. Preparation of polymerizable mixtures HEMA: 97.9-98.1% EGDMA: 1.2-1.4% Irgacure 651: 0.5% Irgacure 819: 0.2%

[0327] The polymerizable mixture was prepared as described in previous experiments corresponding to oxygen equilibrium concentrations of <0.5 volume%, such as the preparations of PM-1A and PM-2.

[0328] 3D printing conditions: PMMA (poly(methyl methacrylate)) domes treated with Tween80 were degassed overnight, labeled D and E, and then used as substrates. After printing each layer, UV pinning was performed at 400 nm for 15 seconds, depositing six layers ranging in diameter from 4 mm to 11 mm, and final curing was performed at 365 nm for 120 seconds.

[0329] result Three measurements were taken of two PMMA domes printed with hydrogel surfaces, and the measurements included three values: the flattest radius of curvature, the steepest radius of curvature, and the principal axis. PMMA domes tilted upwards and downwards: 1. 8.09 / 8.06@180 2. 8.10 / 7.94@120 3. 8.12 / 7.95@112 Average: 8.10 / 7.99 PMMA Dome E is tilted upwards and very slightly to the left: 1. 8.16 / 7.97@82 2. 8.16 / 7.97@97 3. 16 / 7.96@94 Average: 8.16 / 7.97

[0330] The results demonstrate the following: i. The presence of regular optical surfaces (this is a surface feature necessary for measurement with an automated corneameter). ii. Highly repeatable measurements of both the flattest and steepest radii: Dome D: flat range 0.03 mm, steepest range 0.12 mm; Dome E: flat range 0.00 mm, steepest range 0.01 mm. The axis indicates the principal direction and has changed because the dome was placed in front of the instrument without special markings; therefore, this variation is unrelated. iii. Both domes exhibited a small amount of astigmatism. Astigmatism was calculated based on the two assumed refractive indices using the degree equation explained by the measurement of the radius of curvature.

[0331] PMMA dome D with hydrogel surface (n=1.49): Power l=60.49D; Power 2=61.32D; Astigmatism=0.83D; (n=1.42): Power 1=51.85D; Power 2=52.57D; Astigmatism=0.72D.

[0332] PMMA dome F with hydrogel surface (n=1.49): power l=60.05D; power 2=61.48D; astigmatism=1.43D; (n=1.42): power 1=51.47D; power 2=52.69D; astigmatism=1.22D.

[0333] The front surface of the PMMA dome printed on the hydrogel surface described above corresponds to the front surface of an equivalent toric contact lens, with dome D corresponding to a 0.75D toric contact lens and dome E corresponding to a 1.25D toric contact lens.

[0334] Example Series C - Preparation of the Implantable Insertion Section Preparation of polymerizable mixtures: This is the same as in Example Series B. The polymerizable mixture was prepared as described in previous experiments corresponding to oxygen equilibrium concentrations of <0.5 vol% as in the preparation of PM-1A and PM-2.

[0335] 3D printing conditions; The oxygen concentration in the atmosphere was maintained at <0.5 volume percent and measured by two oxygen probes, one placed near the printing station and the other near the UV station. Oxygen concentration control was achieved by a flow meter connected to a nitrogen tank.

[0336] Degassed polypropylene spheres treated with Tween80 were used as the substrate. After printing each layer, UV pinning was performed at 400 nm for 15 seconds, depositing six layers ranging in diameter from 4 mm to 11 mm. Blue-colored PMMA inserts (6 mm in diameter, 50 microns thick) treated with Tween80 were degassed overnight and placed on top of the pinned layers. Two additional layers were deposited with a diameter of 11 mm, each pinned and then UV pinned at 400 nm for 15 seconds. Final curing was performed at 365 nm for 120 seconds.

[0337] result: The blue-colored PMMA insert was clearly visible and found to be completely embedded within the hydrogel device. Furthermore, this method can be used in the manufacture of soft contact lenses with a rigid insert for masking astigmatism.

[0338] Example Series D - Preparation of an embedded reservoir or depot Preparation of polymerizable mixtures: The preparation is the same as that for PM-2. The polymerizable mixture was prepared as described in the previous experiment, corresponding to an oxygen equilibrium concentration of <0.5 volume%, as in the preparations of PM-1A and PM-2.

[0339] 3D printing conditions: The oxygen concentration in the atmosphere was maintained at <0.5 volume percent and measured by two oxygen probes, one placed near the printing station and the other near the UV station. Oxygen concentration control was achieved by a flow meter connected to a nitrogen tank.

[0340] A 13mm diameter glass hemisphere treated with Tween80 was used as the substrate. After printing each layer, UV pinning was performed at 400nm for 15 seconds, depositing 15 layers to a diameter of 9.5mm. Then, small pieces of plastic micropipettes packed with edible coloring crystals were placed on top of the 15 pinned layers. After printing each layer, UV pinning was performed at 400nm for 15 seconds, depositing three more layers to a diameter of 9.5mm. A few drops of further polymerizable mixture were deposited to ensure complete encapsulation of the micropipette pieces, and the assembly was cured at 365nm for 120 seconds.

[0341] result A plastic micropipette containing crystals of food coloring was clearly observed and completely embedded within the hydrogel device. This method demonstrates the embedding of functional additive-releasing reservoirs or depots within ophthalmic devices such as contact lenses. Subsequently, hydration of the assembly in water showed that the hydrated water was colored, and no food coloring crystals were present within the micropipette piece.

[0342] Example Series E - Preparation of Asymmetrical Design Ophthalmic Devices Preparation of polymerizable mixtures The preparation is the same as that for PM-2. The polymerizable mixture was prepared as described in the previous experiment, corresponding to an oxygen equilibrium concentration of <0.5 volume%, as in the preparations of PM-1A and PM-2.

[0343] 3D printing conditions; The oxygen concentration in the atmosphere was maintained at <0.5 volume percent and measured by two oxygen probes, one placed near the printing station and the other near the UV station. Oxygen concentration control was achieved by a flow meter connected to a nitrogen tank.

[0344] A 13mm diameter glass hemisphere treated with Tween80 was used as the substrate. Ten layers with an asymmetrical design (Atheneum Optical Sciences Logo) of approximately 6mm x 4mm were deposited on the substrate, with UV pinning at 400nm for 15 seconds after printing each layer. Next, 17 layers were deposited, with UV pinning at 400nm for 15 seconds after printing each layer. The assembly was then cured at 365nm for 120 seconds.

[0345] result The asymmetrical design of the logo can be clearly observed within the hydrogel device before and after hydration with saline solution. This method demonstrates the feasibility of incorporating asymmetrical structures to correct asymmetric refractive errors in ophthalmic devices such as contact lenses. Example Series F - Preparation of Samples with Image Quality Optical System and Refractive Correction Preparation of polymerizable mixtures: HEMA: 95.4% MAA: 2.5% EGDMA: 1.2% TMPMA: 0.1% Irgacure 819: 0.3% Irgacure 651: 0.5%

[0346] The polymerization mixture was prepared as described in the previous experiment, corresponding to an oxygen equilibrium concentration of <0.5 volume%, similar to the preparations of PM-1A and PM-2.

[0347] 3D printing conditions; The oxygen concentration in the atmosphere was maintained at <0.5 volume percent and measured by oxygen probes placed near the printing and pinning stations. Oxygen concentration control was achieved by a flow meter connected to a nitrogen tank. The resolution of the Samba printhead was set to 1200 dpi.

[0348] A circular design with a diameter of 10.0 mm was printed to produce the sample. The belt speed was set to 10.0 feet per minute (3.05 meters per minute). UV pinning or gelation occurred after 10 seconds of exposure to a 400 nm UV lamp. Curing was performed by irradiation with a 365 nm UV lamp for 120 seconds. For the printed prescriptions, the base layer was printed, pinned, and cured first. Each prescription was then pinned and cured for 120 seconds, followed by the printing, pinning, and curing of the topcoat or final coat. The substrate used to prepare the sample was a glass microscope slide treated with Tween80 as described in Example Series A. The degree of dryness (D) was measured with a Topcon CL-200. Dry samples were measured on printed samples containing a glass slide substrate. Wetness was measured after releasing the sample from an aqueous solution (heated distilled water containing Tween 80 as described above) and then equilibrating it in physiological saline for more than 20 hours. The diameter of the hydrated sample was measured to be 13.9 ± 0.1 mm.

[0349] The results are shown in the table below:

[0350]

number

[0351] result The dry and wet degree results shown in the table above suggest that 3D deposition printing can produce optical devices with optical systems of image quality similar to ophthalmic lenses for correcting refractive errors.

[0352] General findings While this specification and claims may refer to mixtures (such as polymerizable mixtures), initiators, and other additives, the materials and compositions defined herein may consist of one, two, or more types of individual components, which is within the scope of the present invention. In such embodiments, the total amount of each component should correspond to the amount of each individual component as defined above.

[0353] In expressions such as mixture(s) and initiator(s), the (plural) indicates that there may be one, two, or more individual components. On the other hand, when the expression 1 is used, only one (1) of each component exists.

[0354] Unless otherwise specified, percentages should be understood to represent the weight percentage of each component.

[0355] conclusion

[0356] Numerous embodiments of the Disclosure have been described. While this Specification includes details of many specific embodiments, these should not be construed as limiting the scope of any disclosure or claims, but rather as describing features specific to particular embodiments of the Disclosure.

[0357] Certain features described herein in the context of separate embodiments may be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may be implemented separately or in combination in any suitable subcombination in multiple embodiments. Furthermore, features are described above as acting in a particular combination, and may even be initially claimed as such, but one or more features from the claimed combination may be removed from the combination in some cases, and the claimed combination may be directed towards a subcombination or a variation of a subcombination.

[0358] Similarly, while operations are depicted in a specific order in the diagrams, this should not be understood as requiring that such operations be performed in a specific order, sequentially, or all illustrated operations to achieve the desired result. In certain circumstances, multitasking and parallel processing may be advantageous.

[0359] Furthermore, the separation of various system components in the embodiments described above should not be understood as necessary in all embodiments, and the described program components and systems can generally be integrated together in a single hardware and / or software product, or packaged in multiple products.

[0360] Thus, specific embodiments of the subject matter have been described. Other embodiments are within the scope of the following claims. In some cases, the operations described in the claims may be performed in a different order to obtain the desired results. Furthermore, the steps depicted in the accompanying figures do not necessarily require a specific or sequential order to achieve the desired results. In certain embodiments, multitasking and parallel processing may be advantageous. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the claimed disclosure.

Claims

1. A method for forming an ophthalmic lens by additive manufacturing, wherein the method is a. A step of positioning the substrate at a first position relative to the additive manufacturing print head, b. A step of releasing a first pattern of deposited droplets of a polymerizable mixture from a print head, wherein the first pattern of deposited droplets of the polymerizable mixture corresponds to a first portion of a grayscale image. c. A step of receiving deposited droplets of the polymerizable mixture on a receiving surface, wherein the receiving surface includes the substrate and / or the previously released droplets of the polymerizable mixture. d. The step of repositioning the substrate to the following position relative to the print head, e. Discharging from the print head the following pattern of deposited droplets of polymerizable mixture corresponding to the following portion of the grayscale image, f. A step in which steps a. to e. are repeated multiple times while the print head passes over the substrate. g. A step of exposing the deposited droplets of the polymerizable mixture on the receiving surface to a pinning step that causes partial polymerization of the deposited droplets of the polymerizable mixture, h. Repeat step f. for the next pass of the print head over the substrate. i. A step following each pass in step h, which allows gravity to act on at least a portion of the deposited droplets of the polymerizable mixture to smooth the surface of the polymerizable mixture. j. A step of forming a bonded volume of polymerizable mixture on the substrate by integrating at least a portion of the deposited droplets of the polymerizable mixture deposited in the current pass, following each pass included in step h., with the polymerizable mixture previously deposited on the receiving surface. k. Following each step j, the step of pinning the deposited droplets of the polymerizable mixture on the receiving surface via the partial polymerization of the deposited droplets of the polymerizable mixture, and l. A step of curing the bonded volume portion of the polymerizable mixture on the substrate, Methods that include...

2. The method according to claim 1, further comprising the step of encapsulating the deposited droplets of the substrate and the polymerizable mixture in an atmosphere controlled to have a maximum oxygen concentration of 5.0 volume percent.

3. The method according to claim 2, comprising the step of bringing the oxygen equilibrium concentration of the bonded volume portion of the polymerizable mixture on the substrate to a maximum of 8.0 volume percent.

4. The method according to claim 3, further comprising the step of bringing the oxygen concentration in the substrate into equilibrium with the oxygen concentration in the controlled atmosphere.

5. The method according to claim 4, wherein at least one of the steps of releasing a first pattern of polymerizable mixture deposit droplets from the print head and releasing a subsequent pattern of polymerizable mixture deposit droplets from the print head includes releasing an amount of polymerizable mixture deposit in a given arrangement corresponding to data values ​​associated with pixels contained in the grayscale image.

6. The method according to claim 5, wherein a relatively larger digital value corresponds to a darker region of the grayscale image than a relatively smaller digital value corresponds to a brighter region of the grayscale image.

7. The method according to claim 1, wherein the pinning step includes the step of exposing the deposited droplets of polymerizable mixture to chemical radiation of a first wavelength for a limited time such that the pinning step does not cause the deposited droplets of polymerizable mixture to gel and harden.

8. The method according to claim 1, wherein the step of curing the bonded volume portion of the polymerizable mixture includes exposing the bonded volume portion of the polymerizable mixture on the substrate to chemical radiation of a second wavelength for a time and intensity sufficient to cause polymerization of deposited droplets of the polymerizable mixture.

9. The method according to claim 1, wherein the step of allowing gravity to act on at least a portion of the deposited droplets of the polymerizable mixture to smooth the surface of the polymerizable mixture includes at least partially filling the intervening spaces between the deposited droplets of the polymerizable mixture.

10. The method according to claim 9, further comprising the step of bringing the oxygen concentration in the substrate to equilibrium with the oxygen concentration in a controlled atmosphere containing the substrate and the deposited droplets of the polymerizable mixture.

11. A method for forming an ophthalmic lens by additive manufacturing, wherein the method is a. A step of positioning the substrate at a first position relative to the additive manufacturing print head, b. A step of releasing a first pattern of deposited droplets of polymerizable mixture from the additive manufacturing print head, wherein the first pattern of deposited droplets of polymerizable mixture corresponds to a first portion of an energy transmission pattern. c. A step of receiving the deposited droplets of the polymerizable mixture on a receiving surface, d. A step of positioning the substrate with respect to the additive manufacturing print head at the following position (current position plus N), e. A step of releasing a subsequent pattern of deposited droplets of polymerizable mixture corresponding to the next portion of the energy transmission pattern, f. A step that allows a physical force to smooth the surface of the polymerizable mixture droplets deposited in the current pass, g. A step of integrating at least some of the deposited droplets of the polymerizable mixture deposited in the current pass with the polymerizable mixture previously deposited on the receiving surface to form a bonded volume of the polymerizable mixture on the substrate. h. A step of exposing the deposited droplets of the polymerizable mixture on the receiving surface to a pinning step that causes partial polymerization of the deposited droplets of the polymerizable mixture. i. For multiple passes of the additive manufacturing print head on the substrate, the steps d to h are repeated, and j. A step of manufacturing the formed ophthalmic lens by curing the bonded volume portion of the polymerizable mixture on the substrate. Methods that include...

12. The method according to claim 11, wherein the step of receiving the deposited droplets of the polymerizable mixture on the receiving surface includes receiving the deposited droplets with one or more of the substrate, droplets released in front of the polymerizable mixture, and insertion portions.

13. The method according to claim 12, further comprising repeating steps d. to g. multiple times while the additive manufacturing print head passes over the substrate.

14. The method according to claim 12, further comprising the step of releasing the formed ophthalmic lens from the substrate.

15. The method according to claim 12, further comprising the step of allowing gravity to act on at least a portion of the deposited droplets of the polymerizable mixture to at least partially fill the intervening spaces between the deposited droplets of the polymerizable mixture.

16. The method according to claim 11, wherein the pinning step includes a step of exposing the deposited droplets of polymerizable mixture to chemical radiation of a first wavelength for a limited time that is sufficient not to cause gelation of the deposited droplets of polymerizable mixture and hardening of the deposited droplets of polymerizable mixture.

17. The method according to claim 16, wherein the step of curing the bonded volume portion of the polymerizable mixture on the substrate includes exposing the bonded volume portion of the polymerizable mixture on the substrate to chemical radiation of a second wavelength for a time and at an intensity sufficient to cause polymerization of the bonded volume portion of the polymerizable mixture on the substrate.

18. The method according to claim 11, further comprising the step of housing the substrate and the polymerizable mixture in a controlled atmosphere having an oxygen concentration of up to 2.0 volume percent.

19. The method according to claim 18, further comprising the step of bringing the oxygen concentration in the substrate into equilibrium with the oxygen concentration in the controlled atmosphere.

20. The method according to claim 11, further comprising the step of dithering the energy transmission pattern before generating a control command.

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