Multifocal polymer lenses and manufacturing methods

Abstract

A multifocal ophthalmic lens and a method for producing a multifocal ophthalmic lens having multiple sub-optical elements along the same optical path include intermittent pinning of a deposited polymerizable mixture and final curing of the deposited polymerizable mixture. The intermittent pinning can form sub-optical elements. A pattern of multiple defined regions can be fabricated, each region representing an amount of energy transfer associated with that region. Each region can have a light value based on a scale, such as an 8-bit, 16-bit, 32-bit, 64-bit scale, or other scale. In some embodiments, each region can refer to the smallest single component of a digital image.

Description

[Technical Field]

[0001] (Reference to related application) This application claims priority to U.S. Non-provisional Application No. 18 / 235,586, filed August 18, 2023, which in turn claims the benefit of U.S. Provisional Application No. 63 / 447,493, filed February 22, 2023, the entire disclosures of each of which are incorporated herein by reference.

[0002] The present invention relates to the field of improved ophthalmic lenses, and in particular to a method and apparatus for forming multifocal ophthalmic devices by repeatedly applying droplets of polymerizable material that exhibit energy transmission mappings with multiple different optical powers, and the resulting lenses. [Background technology]

[0003] Cast multifocal ophthalmic lenses currently rely on optical power zones that can be applied to the lens mold via lathing techniques. Reliance on such techniques has inherent limitations in ophthalmic lens design. Users often have difficulty adjusting to wearing lenses with optical power zones, which can cause problems with depth of field perception and / or difficulty ascertaining focus on objects at various distances from the patient's eye.

[0004] Additionally, the zones within a contact lens generally have optical properties that are tailored to the patient's eye only, and multifocal contact lenses sometimes have a tendency to rotate within the eye, which can further adversely affect the vision correction experience provided by zone-based ophthalmic lenses.

[0005] Contact lens manufacturing has evolved over the past few decades from lathe cutting to spin-cast molding, and then to cast molding, which is the most cost-effective process. Lashing contact lenses typically involves machining a single button of lens material at a time until the desired shape is achieved. Such processes require complex lathe-cutting equipment and specialized operator expertise. They are also not efficient for mass production of contact lenses.

[0006] Although cast molding is effective for mass-producing contact lenses, each lens is formed to an approximate size and shape, which can vary by up to 1 / 8 or 1 / 4 diopter in the same manufacturing process, resulting in a wide variety of patient experiences, sometimes referred to as "good contact lens days" and "bad contact lens days."

[0007] Casting ophthalmic lenses is a complex process with many variables that are difficult to maintain within acceptable parameters and that result in varying results in the final product. The variables can arise from one or more of depositing a curable mixture of polymerizable monomers into a mold cavity, forming the mold cavity through two mold sections, curing the monomer mixture while it is contained within the cavity, disassembling the mold assembly, and removing the lens. One mold section forms the anterior lens surface, and the other mold section forms the posterior lens surface.

[0008] The size of the manufacturing line makes the cost of the casting equipment prohibitive. Additionally, the manufacture of the optical-quality metal inserts used to cast the disposable lens molds and the subsequent injection molding of the plastic molds requires significant upfront investment, and the associated designs are limited by the symmetry constraints of the casting molding technology. Casting also generates a large amount of plastic waste, resulting in harmful environmental impacts and additional costs.

[0009] Furthermore, cast molding requires inventory management of a large number of SKUs and the associated warehousing, order pickup, and logistics challenges, all of which add significant environmental harm and cost to the resulting contact lens product. Additionally, the family of contact lenses produced by the lens molding process can only have a limited number of variations in optical power, base curve, and diameter. Summary of the Invention

[0010] Thus, the present invention provides improved methods and apparatus for the manufacture of articles having qualities that facilitate their use as multifocal optical lenses, for example, for use as contact lenses, intraocular lenses, or other ophthalmic lenses. The new ophthalmic lens types feature multiple optical properties in the same optical path through the ophthalmic lens. The new ophthalmic lens types include multiple sub-optical elements in the same optical path visible to the lens wearer. Multifocal optical elements are also useful in applications unrelated to biological vision, such as, by way of non-limiting example, use with endoscopes, automated vision, or other electro-optical devices.

[0011] Aging affects the ability of a person's ciliary muscles and zonular fibers to adjust the shape of a person's eye lens, as well as the autonomic nervous system control of these structures. In addition, the brain's selection and processing of images can also be affected by age-related changes in the visual system. These changes can lead to a decrease in a person's visual acuity and ability to focus on objects at various distances. The present invention provides an ophthalmic lens that helps the human body achieve vision and allows the human body to focus on objects at various distances by providing multiple sub-optical elements within the same line of sight. The human brain can process images from neurologically selected images through the sub-optical elements provided by the ophthalmic lens.

[0012] An ophthalmic lens having multiple sub-optical elements in the same optical path is formed by repeatedly applying a monomer onto a receiving surface according to an optical design. In some embodiments, the optical design may include an energy intensity map (e.g., a grayscale image) that maps the intensity of an energy spectrum associated with visible light.

[0013] Intermittent pinning of the deposited polymerizable mixture facilitates the formation of multiple sub-optical elements. Final curing, hydration, and release of the deposited monomer forms the multifocal ophthalmic lens. The additive manufacturing apparatus can be controlled to make multiple passes of one or both of the print head and receiving surface to add polymerizable material to the receiving surface to form a lens (or other article) according to an axial thickness profile including in-air lens power (P), lens refractive index (n), center thickness (CT), and back surface radius of curvature (RB).

[0014] According to the present invention, one or both of the print head and receiving surface can be positioned during deposition that is not perpendicular to the apex (tilt) of the receiving surface, and the droplets of monomer ejected by the print head can be aspherical when they contact the receiving surface. The tilt combined with the rotation of one or more of the receiving surface, the print head, and the pattern of deposited monomer between the deposition path of the print head and the receiving surface creates multiple sub-optical elements in the article formed along the same optical path. Patients wearing multifocal lenses can neurologically select which sub-optical element(s) to perceive when focusing on objects in their field of view.

[0015] The present invention provides a multifocal lens without the complexity of different zones and the inconvenience of having to wear the lens in a specific vertical orientation to obtain a satisfactory visual experience.

[0016] Improvements also include reducing waste, lowering environmental impact, reducing warehouse overhead, and reducing the labor required to manufacture and store ophthalmic lenses.

[0017] In some embodiments, the present invention provides lenses that can be produced through two or more components, including an optic zone (sometimes referred to herein as "OZ") and a peripheral zone, or edge portion, where one or both of the optic zone and peripheral zone can be formed based on an energy intensity pattern that describes a non-hydrated axial thickness profile.

[0018] Some embodiments of the present disclosure may include a method of forming an ophthalmic lens via additive manufacturing, the method comprising positioning a substrate at a first position relative to an additive manufacturing print head and ejecting a pattern of deposited droplets of a polymerizable mixture from the print head, the pattern of deposited droplets of the polymerizable mixture corresponding to a portion of an energy transmittance map of the ophthalmic lens.

[0019] Some embodiments of the present invention include receiving deposited droplets of a polymerizable mixture onto a receiving surface, the receiving surface including one or both of a substrate, an insert, and a previously ejected polymerizable mixture. Embodiments may include repositioning the substrate from a first position to a next position (current position + N) relative to the print head. The repositioning may be accomplished via movement of one or both of the substrate and the print head.

[0020] Further, variations of the present invention may include ejecting a next pattern of deposited droplets of the polymerizable mixture (first position +N) corresponding to a next portion of the energy transmissibility map of the ophthalmic lens being formed. Multiple ejections may occur during a pass of the print head over a receiving surface, which may include a substrate.

[0021] Some variations of the present invention may include consolidating material from deposited droplets of the polymerizable mixture on the receiving surface and exposing the consolidated material to a pinning process that causes partial polymerization of the deposited droplets of the polymerizable mixture. After the printhead passes, one or more of gravity, surface tension, and microforces may act on at least some of the deposited droplets to smooth the polymerizable mixture on the receiving surface, such as leveling gaps between the deposited droplets.

[0022] In some embodiments, at least some of the droplets of polymerizable mixture deposited during the passage of current may merge with previously deposited polymerizable mixture on the receiving surface to form the same volume that may contain 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 hardening the deposited droplets of polymerizable mixture. The consolidation of the deposited droplets alleviates the disclosed process from the requirement for the droplets to maintain a particular shape during deposition, impact, or after impact.

[0023] In some embodiments, the pinning process can include exposing the deposited droplets of the polymerizable mixture to actinic radiation at a first wavelength for a limited time sufficient to cause gelation of the deposited droplets of the polymerizable mixture, but not sufficient to cause hardening of the deposited droplets.

[0024] Additionally, in some embodiments, the curing process may include exposing the deposited droplets of the polymerizable mixture to actinic radiation of a second wavelength for a sufficient time and intensity to cause polymerization of the deposited droplets of the polymerizable mixture deposited in one or more droplet deposition cycles.

[0025] The present invention further provides methods of manufacturing that include a perimeter of the formed object and a central portion of the object housed with the perimeter portion. For example, in some embodiments of the present invention, an ophthalmic contact lens having a generally spherical shape may have an edge portion comprising an essentially ring-shaped volume of a polymerizable mixture formed via additive manufacturing (or other manufacturing methods such as machining and / or molding), and an optic zone of the contact lens formed within the perimeter portion via the additive manufacturing process.

[0026] In some embodiments of the invention, the edge portion may comprise more mass than the central portion comprising the optic zone. During molding, the peripheral ring forming the edge may be partially or fully cured, and the internal stresses of the molded lens may be borne more in the heavier mass contained in the peripheral ring.

[0027] Forming the edge portions while not acted upon by the central portion allows the edge portions to be formed with reduced stress during curing of the polymerizable mixture deposited on the polymer. Although the examples provided herein are described with reference to spherical contact lenses, other embodiments are within the scope of the invention, such as rectangular or crescent shaped contact lenses, or other articles such as complex shaped intraocular lenses, endoscopic lenses, or electronic device camera lenses.

[0028] In some embodiments, the present invention provides for the application of a pattern of multiple defined regions contained within a single lens, each region representing the amount of light transmittable through its associated region, each region may have a light transmittance value 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).

[0029] 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 be referred to herein as a "pixel." In some embodiments, a pixel may be associated with a distance measurement, such as, for example, a quantity of nanometers.

[0030] The present invention provides for the subsequent application of polymerizable material in multiple successive patterns, each successive pattern corresponding to a grayscale image, where after application of each pattern of the grayscale image, the polymerizable material is pinned but not fully polymerized.

[0031] After the final application of the monomer in the pattern of the grayscale image, the aggregated monomer from each application of the grayscale image is polymerized to form a polymeric lens, such as, for example, a hydrogel contact lens formed primarily from etafilcon.

[0032] The application of multiple successive grayscale image patterns is preferably performed in a controlled atmosphere, and multiple successive grayscale image patterns may be overlapping and positioned alongside one another. The atmosphere may be controlled to limit, by way of non-limiting example, certain amounts of variables, such as airborne particulates and / or gases present in the atmosphere during certain process steps involved in the manufacturing process. As a specific example, preferred embodiments include an atmosphere having a limited amount of oxygen to which the monomer is exposed prior to polymerization, and also limiting the size and amount of particles that may interact with the monomer prior to polymerization.

[0033] In some embodiments, oxygen can be controlled in some monomers or other polymerizable mixtures as a key variable involved in the free radical polymerization of monomer materials and prepolymers involved in the manufacturing process. Limiting the amount of oxygen to which the monomer is exposed may be particularly relevant for ophthalmic devices formed from hydrogels containing relatively low levels of crosslinker that are hydrated after polymerization, making them prone to shape distortion from deformation of the resulting polymer network. Limiting the amount of oxygen to which the polymerizable mixture is exposed may also be particularly relevant for additive manufacturing processes that involve small droplets of the polymerizable mixture passing through the ambient atmosphere. Small droplets of the polymerizable mixture increase the surface area of ​​the polymerizable mixture's exposure to potential external factors (for a given volume of polymerizable mixture required to manufacture a lens) during the time the polymerizable mixture remains in droplet form in the ambient atmosphere. As the droplets coalesce into larger volumes on the receiving surface, the surface area decreases.

[0034] According to another aspect of the present invention, exposure of the polymerizable mixture to a gas (such as oxygen) that may affect the polymerization characteristics of the polymerizable mixture is therefore carefully controlled by one or more of the amount of exposure of the polymerizable mixture, the consistency of exposure throughout the monomer, and the duration of exposure to the gas. It has been found that if, during polymerization, the oxygen concentration is higher in one side (side 1) (or other portion of the monomer forming the optical device) compared to a second side (side 2) or another region, side 1 may expand relatively more than side 2 does, resulting in distortion of the inherent optical properties of the resulting optical device.

[0035] Similarly, one portion of the polymerizable mixture having a greater or lesser oxygen concentration may expand by a different amount than another portion having a different amount of oxygen concentration. By limiting the availability of oxygen to the polymerizable mixture prior to polymerization, a relatively consistent oxygen concentration can be maintained within the polymerizable mixture, thereby achieving a consistent expansion coefficient caused by oxygen concentration.

[0036] In some embodiments, the effects of oxygen may be managed prior to polymerization of the polymerizable mixture using relatively high concentrations of initiator, high intensity UV light energy, oxygen scavengers, waxes, or coatings, but to date, none of these have been shown to consistently produce high quality optical devices.

[0037] The present invention takes a new approach in the use of three-dimensional (sometimes referred to as "3D") printing devices to create optical elements, such as ophthalmic devices, by controlling the presence and concentration of oxygen to low levels and / or simultaneously regulated concentrations. In some embodiments, it is beneficial to control the oxygen level in the polymerizable mixture relative to the oxygen level in the atmosphere surrounding the polymerizable mixture during the fabrication of the optical device to obtain desired dimensions and resulting optical properties of the optical elements included in the optical device. This principle may also be extended to include the substrate onto which the deposited monomer is received. Thus, some embodiments of the present invention may include the oxygen level being maintained at a predetermined level within the receiving substrate before and during the polymerization process.

[0038] The present invention also includes a method for three-dimensional deposition printing of multifocal optical elements, in which a plurality of droplets of a polymerizable mixture are deposited on the surface of a substrate under a controlled atmosphere, thereby forming a pattern of energy intensity transmission through the deposited polymerizable mixture, such as a grayscale pattern with the polymerizable mixture. The controlled atmosphere containing the droplets of the polymerizable mixture and the deposited pattern of the polymerizable mixture is maintained in a controlled environment with an oxygen concentration of up to about 5.0% by volume (preferably up to about 1.0% by volume). The oxygen equilibrium concentration of the polymerizable mixture may be limited to up to about 8.0% by volume (preferably up to about 2.0% by volume). In this context, due to the constraints of measuring the volume percent of oxygen in the polymerizable mixture and the surrounding environment, "about" may be considered to be within 10% of the stated amount. [Brief explanation of the drawings]

[0039] [Figure 1] FIG. 1 shows a schematic diagram of a multifocal lens with side and elevation views according to some embodiments of the present invention. [Figure 1A] FIG. 1A illustrates an exemplary additive manufacturing apparatus that may be used in some embodiments of the present invention. [Figure 1B] FIG. 1B shows a schematic diagram of a mechanism for introducing a gradient into an additive manufacturing system. [Figure 1C]FIG. 1C shows an exemplary graphical representation of the optical power available in the optical path through an ophthalmic lens according to the present invention. [Figure 1D] FIG. 1D shows a schematic view of the print head relative to the receiving substrate. [Figure 1E] FIG. 1E shows an electro-active device for providing camber movement to one or both of the print head and receiving substrate. [Figure 2] FIG. 2 is a schematic diagram of an alternative 3D printing apparatus according to some embodiments of the present invention. [Figure 3] FIG. 3 shows an exemplary energy intensity pattern, represented as a grayscale image, that may be used to generate a control protocol for a 3D printing device, according to some embodiments of the present invention. [Figure 3A] FIG. 3A shows a schematic diagram of an exemplary energy intensity pattern represented as a grayscale image. [Figure 3B] Figure 3B shows a schematic diagram of a conventional 3D printing process. [Figure 3C] FIG. 3C shows a schematic diagram of the process steps according to the present invention. [Figure 4] FIG. 4 is a schematic diagram of a spherical lens with identified peripheral portions, according to some embodiments of the present invention. [Figure 5] FIG. 5 is a schematic illustration of a cross-sectional view of a lens having a peripheral portion and a carrier portion supporting an optic zone, according to some embodiments of the present invention. [Figure 6] FIG. 6 shows a graphical curve representing an exemplary hydrated surface of an ophthalmic lens that can be formed in accordance with the present invention. [Figure 7] FIG. 7 shows a graphical curve representing an exemplary unhydrated axial thickness of an ophthalmic lens that can be formed in accordance with the present invention. [Figure 8] FIG. 8 is a schematic diagram of a false color image of the peripheral region. [Figure 9] FIG. 9 is a schematic illustration of a false color image of a full lens thickness profile with a transition region zone. [Figure 10]FIG. 10 shows a false color image of the thickness profile of the peripheral zone of an astigmatic lens. [Figure 11] FIG. 11 shows a false color image of the thickness profile of an astigmatic lens. [Figure 12] FIG. 12 illustrates method steps that may be performed while practicing some implementations of the present invention. [Figure 13] FIG. 13 is a schematic illustration of a deposited droplet of polymerizable mixture incorporated into a volume of polymerizable mixture previously deposited on a substrate. [Figure 13A] FIG. 13A is a schematic illustration of a deposited droplet of polymerizable mixture incorporated into a volume of polymerizable mixture previously deposited on a substrate. [Figure 13B] FIG. 13B is a schematic illustration of a deposited droplet of polymerizable mixture incorporated into a volume of polymerizable mixture previously deposited on a substrate. [Figure 14] FIG. 14 is a schematic illustration of an exemplary change in shape of a droplet of a polymerizable mixture after release from a printhead. [Figure 15] FIG. 15 shows a flowchart of method steps that may be performed in some implementations of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0040] According to the present invention, ophthalmic lenses having multiple optical properties, such as optical power along the same optical path, can be constructed by applying small droplets of a polymerizable mixture to a receiving surface based on a pattern or map of energy transmittance. As used herein, with respect to ophthalmic lenses, optical properties can include the interaction of the ophthalmic lens with electromagnetic radiation in the visible light spectrum.

[0041] The present invention provides an ophthalmic lens having optical properties at sub-optical elements along the same optical path formed in the ophthalmic lens via the process described herein for forming the ophthalmic lens. For example, optical properties can be formed in the body of the ophthalmic lens via pinning deposited droplets of a polymerizable mixture on a receiving surface, prior to subsequent deposition of additional droplets onto the pinned polymerizable mixture. Final curing of the deposited polymerizable mixture forms an article that can be hydrated and used as an ophthalmic lens. A person wearing the ophthalmic lens can focus on an item in their line of sight and neurologically select which optical properties to perceive while looking along the same optical path.

[0042] The ability to neurologically select optical properties along the same optical pathway mimics a person's natural visual experience and is more natural than previous multifocal lenses, which required selecting different optical pathways across small, disparate optical zones contained within the previous multifocal lens.

[0043] As people age, it is normal for the anatomy of the eye to change, including a decrease in the ability of a person's ciliary and zonular muscles to adjust the shape of the eye's lens. Such anatomical changes (commonly referred to as presbyopia) can lead to a decrease in the ability to focus on objects at various distances.

[0044] Specifically, as a result of aging, the ciliary muscles become less flexible, making it more difficult for them to adjust the shape of the eye lens. As people age, the zonules in the human eye weaken and become less elastic. This causes the lens to become less flexible and less able to change shape. This results in a decrease in the eye's ability to focus on nearby objects, a condition known as presbyopia. This condition is a normal part of the aging process and is usually noticed in people over the age of 40. The weakening of the zonules also makes the lens more opaque. The overall effect is a more limited range of accommodation, making it more difficult to focus on nearby objects.

[0045] Additionally, autonomic nervous system control of the ciliary muscle and zonular fibers is also typically affected by aging. Research has shown that as people age, parasympathetic activity controlling the ciliary muscle decreases, leading to a decline in accommodative ability, while the brain's processing speed and accuracy in selecting images processed by the visual system also decrease, negatively impacting the ability to process images quickly and efficiently.

[0046] In a related aspect, the human sympathetic nervous system plays a role in controlling the ciliary muscle during accommodation for distance vision. When viewing a distant object, the sympathetic branch of the ANS is activated, causing the ciliary muscle to relax. This relaxation increases tension in the zonular fibers, allowing the lens to flatten and reduce its refractive power. The brain plays a key role in selecting the image to be processed by the visual system. The visual cortex receives information from the eyes and processes it to create a visual perception of the world around us. The brain uses various cues, such as the amount of light, the contrast of an object, and its location within the visual field, to select the image to be processed. Overall, the ANS controls the ciliary muscle and zonular fibers to focus on objects at various distances, while the brain selects the image to be processed from the input provided by the visual system.

[0047] The biological process of focusing on an image (commonly referred to as "accommodation") requires the coordinated action of several structures in the human eye, including the ciliary muscle and zonular fibers. The brain plays a key role in this process by receiving information from the eye and sending signals back to control the muscles and fibers involved. When the eye focuses on a distant object, the ciliary muscle relaxes, the zonular fibers tighten, and the lens flattens. However, when the brain asks the eye to focus on a nearby object, the brain signals the ciliary muscle to contract, while simultaneously signaling the zonular fibers to release tension, making the lens rounder and increasing its refractive power. The brain also takes into account other factors, such as the eye's distance to the object of interest and the amount of light present.

[0048] Coordination of the ciliary muscles and zonular fibers is essential for successful accommodation using biological image generation. The present invention provides an ophthalmic lens that simultaneously presents multiple images to the brain, allowing the brain to select a specific image to process. The multiple images are formed via different sub-optical elements along the same path through the ophthalmic lens according to the present invention. The wearer of the ophthalmic lens according to the present invention can synchronize their neurological processes with their cognitive objectives in order to focus on the available images presented to the optic nerve.

[0049] The process and apparatus of the present invention create multiple distinct sub-optical elements within an ophthalmic lens through sequential application of a polymerizable mixture based on a map of transmittance of visible light energy (or other predetermined pattern). The surface of the ophthalmic lens of the present invention may be a generally planar surface, an arcuate surface, or a complex variable surface. Droplets of the polymerizable mixture applied to the receiving surface accumulate in a pattern of the polymerizable mixture that replicates the map of energy transmittance. After applying the polymerizable mixture to the receiving surface, the applied polymerizable mixture is exposed to a limited amount of actinic conditions, such as radiation (limited in intensity and / or duration) and / or thermal energy. The exposure to the limited amount of actinic radiation is adequate to pin the applied polymerizable mixture in place.

[0050] The pinned polymerizable mixture can act as a subsequent receiving surface to receive additional polymerizable mixture applied in an energy-transparent pattern. After the final application of the polymerizable mixture, the accumulated polymerizable mixture on the receiving surface can be exposed to actinic conditions (e.g., radiation and thermal energy) sufficient to cure the accumulated polymerizable mixture into a polymer.

[0051] The atmosphere containing the droplets of polymerizable mixture during application to the receiving surface and in pendency on the receiving surface before curing can be carefully controlled to achieve consistent optical quality of the device formed by the cured polymerizable mixture.

[0052] Glossary In this specification and in the claims that follow, various terms may be used to which the following definitions apply.

[0053] As used herein, "actinic radiation" refers to the emission of energy capable of initiating a chemical reaction in an associated polymerizable mixture. In some embodiments, actinic radiation includes radiation having a wavelength of energy in the range of 280-450 nm. In some more specific exemplary embodiments, actinic radiation corresponding to UVA and blue light includes energy having a wavelength in the range of 315-450 nm, and some preferred embodiments include energy in the range of 365-400 nm.

[0054] "Additive-based manufacturing" (sometimes referred to herein as "additive manufacturing") refers to a process in which units of material are added to a structure formed by the aggregation of units of material into a shape.

[0055] As used herein, "arcuate" refers to a geometric shape that includes curved portions.

[0056] As used herein, "curing" refers to exposing a polymerizable mixture to actinic radiation conditions that may include fixed radiation and / or thermal energy of sufficient intensity and for a sufficient duration to crosslink a substantial portion of the polymerizable mixture.

[0057] As used herein, "diopter" refers to a unit of optical power equal to the reciprocal of the focal length (usually in meters) of a given sub-optic.

[0058] As used herein, "fixing radiation" refers to actinic radiation of an appropriate wavelength and of sufficient intensity and duration to crosslink a majority of the polymerizable mixture exposed to the fixing radiation.

[0059] "Gelling" or "gel" refers to a degree of polymerization sufficient to stop or substantially slow the movement of the polymerizable mixture deposited on a receiving surface, allowing subsequent droplets to fuse or otherwise integrate with previously deposited polymerizable mixture to form a structure with a single mass of undistorted polymerizable mixture. The gelled polymerizable mixture moves to a higher viscosity state but does not achieve full hardening. Pinning or gelling (or gelling) enhances flow and shape control, providing a high-quality surface.

[0060] As used herein, the term "gel point" refers to the point in the polymerization process at which a gel or insoluble fraction forms. The gel point can be considered the degree of conversion at which a liquid polymerization mixture becomes a highly viscous material that is immobile on a stationary surface. The gel point can be determined, for example, using a Soxhlet experiment: the polymer reaction is stopped at different times, and the resulting polymer is analyzed to determine the weight fraction of residual insoluble polymer. The data can be extrapolated to the point where a gel is not yet present. This point, where some polymer reaction has occurred but no gel is present, is the gel point. The gel point can 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 between plates. At least one plate must be transparent to radiation at the wavelength used for polymerization. The point at which the viscosity approaches infinity is the gel point. The gel point can generally be considered to occur at the same degree of conversion for a given polymer system and specific reaction conditions.

[0061] As used herein, an "inhibitor" refers to a chemical reactant or process that slows or stops a chemical reaction.

[0062] As used herein, "initiator" refers to a substance that starts a chain reaction or polymerization.

[0063] As used herein, "intensity" refers to the amount of power transmitted per unit area, where the area is measured in the direction of energy propagation (e.g., watts per square meter (W / m)). 2)) is measured on a plane perpendicular to the

[0064] As used herein, "meld" (sometimes called "integration") means causing droplets of polymerizable mixture from two or more deposits to merge together so that they become a single item having polymer chains that include the polymerizable mixture from the first deposit and the polymerizable mixture from the second deposit.

[0065] As used herein, "ophthalmic lens" refers to an ophthalmic device that resides in or on the eye. These devices can provide optical correction or can be cosmetic. For example, the term lens can refer to contact lenses, intraocular lenses, overlay lenses, ocular inserts, optical inserts, or other similar devices that correct or modify vision without interfering with vision, or that cosmetically enhance the physiology of the eye (for example, iris color).

[0066] As used herein, "optical" refers to properties that modify or relate to the behavior or properties of light.

[0067] As used herein, "light interface" refers to an object or part of an object that affects the behavior or properties of light.

[0068] As used herein, "pinning" refers to the application of actinic conditions, such as limited exposure to actinic radiation, to a polymerizable mixture in an amount sufficient to effect a gelation process or gelation, but without curing the polymerizable mixture.

[0069] As used herein, "Polymerizable Mixture" (sometimes referred to as "PM" or "polymerizable mixture") refers to a liquid mixture of components (reactive and, in some cases, non-reactive components) that can undergo polymerization to form a polymer or polymer network upon exposure to external energy (e.g., actinic radiation in the range of 280-450 nm (e.g., UV light or blue light or heat)). The polymerizable mixture may include monomer or prepolymer materials that can be cured and / or crosslinked to form an ophthalmic lens or modify an existing lens or lens blank. Various embodiments can include the polymerizable mixture with one or more additives, such as UV blockers, adhesives, tints, photoinitiators or catalysts, and other additives for ophthalmic lenses, contact lenses, or intraocular lenses. In some embodiments, the polymerizable mixture may also be a hydrogel precursor.

[0070] As used herein, "sub-optic" refers to a portion of an ophthalmic lens that forms the optical interface.

[0071] As used herein, the expression oxygen equilibrium concentration of a polymerizable mixture of X is intended to mean the oxygen concentration in the polymerizable mixture that would result if the mixture were equilibrated at 1.0 atmosphere (1013 mbar) with an atmosphere having a hypothetical oxygen concentration of X%.

[0072] As 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, telescopic lenses, etc. Currently, embodiments of particular interest herein are ophthalmic devices.

[0073] In some embodiments, the optical element has one or more objects embedded therein, for example, a solid object selected from an insert, electronics, and a functional additive release reservoir or depot.

[0074] In other embodiments, the optical element includes one or more functionally active substances, including biologically active substances.

[0075] As used herein, an ophthalmic device includes any device located in front of the eye or in any part of the eye, including the cornea, eyelids, and ocular glands. These devices can provide optical correction, cosmetic enhancement (e.g., iris color), vision enhancement, therapeutic effects (e.g., bandage lenses), or therapeutic agents such as lubricants, humectants, active pharmaceutical ingredients (sometimes referred to as "APIs") and biological agents, which may be anti-inflammatory, anti-allergic, antibacterial, anti-infective, anti-hypertensive, etc., or delivery of nutritional supplements, vitamins, and antioxidants for ocular health, or combinations of any of the foregoing. Illustrative examples of ophthalmic devices include those selected from spectacle lenses, contact lenses (e.g., soft or hard contact lenses), implantable contact lenses, intraocular lenses, overlay lenses, corneal implants such as corneal inlay implants, and ophthalmic / ocular inserts.

[0076] In some embodiments, the ophthalmic device is a contact lens, particularly a soft contact lens such as a hydrogel material contact lens, while other embodiments may include a hydrogel material intraocular lens.

[0077] The term hydrogel refers to a crosslinked polymer that has absorbed water (swelled) to a water content of at least 10% by weight. Preferably, such hydrogel materials have a water content of at least 20% by weight, e.g., at least 25% by weight, and up to 70-90% by weight.

[0078] As used herein, the term "polymerizable mixture" refers to a liquid mixture of components (reactive and, in some cases, non-reactive) that can undergo polymerization to form a polymer or polymer network upon exposure to external energy (e.g., actinic radiation 280-450 nm (such as UV light or blue light) or heat). Typically, the mixture includes reactive components such as monomers, macromers, prepolymers, crosslinkers, and initiators. Additionally, the polymerizable mixture may further include other components, such as, by way of non-limiting example, additives such as wetting agents, release agents, dyes, one or more light-absorbing compounds such as ultraviolet absorbers and photochrome compounds, and one or more pharmaceuticals, vitamins, antioxidants, and nutraceutical compounds, any of which may be reactive or non-reactive and can be retained in the resulting ophthalmic device. It will be understood that a wide range of additives may be added depending on the ophthalmic device, how the ophthalmic device is made, and the intended use of the ophthalmic device.

[0079] A mixture may be considered a polymerizable mixture if one or more components of the mixture (e.g., monomer, macromer, prepolymer, crosslinker, etc.) contains at least one polymerizable functional group, such as, but not limited to, an ethylenically unsaturated group, such as (meth)acrylate, (meth)acrylamide, vinyl, N-vinyl lactam, N-vinyl amide, and styryl functionality.

[0080] In some embodiments, the polymerizable mixture includes at least one hydrophilic component, which may be selected from hydrophilic monomers, such as those known to be useful in preparing hydrogels.

[0081] In some exemplary and specific embodiments, hydrophilicity means that at least 5 grams of the compound are soluble in 100 mL of deionized water at 25° C. under weakly acidic (pH 5-7) or basic conditions (pH 7-9), and in some embodiments, 10 grams of the compound are soluble in 100 mL of deionized water at 25° C. under weakly acidic or basic conditions. Other embodiments are also within the scope of the present invention. Additionally, in other applications, "hydrophilicity" can be determined by methods other than solubility, and the term can be used as a condition and / or modifier.

[0082] In some exemplary and specific embodiments, "hydrophobic" means that 5 g of a hydrophobic compound does not completely dissolve in 100 mL of deionized water at 25°C under mildly acidic or basic conditions. The solubility of a compound can be confirmed by visual observation; any visible precipitate or turbidity indicates that the compound is hydrophobic. For example, in some embodiments, solubility can be determined after about 8 hours of mixing or stirring. Other embodiments are also within the scope of the present invention. Additionally, in other applications, the condition of "hydrophobic" can be confirmed by methods other than solubility, and the term can be used as a condition and / or modifier.

[0083] One class of suitable hydrophilic monomers includes acrylic or vinyl-containing monomers. Such hydrophilic monomers themselves can be used as crosslinkers, but when hydrophilic monomers with multiple polymerizable functional groups are used, their concentrations should be limited, as discussed above, to provide contact lenses with the desired coefficients.

[0084] The term vinyl-type or vinyl-containing monomer refers to a monomer that contains a vinyl group (-CH=CH2) and can be polymerized. Examples of hydrophilic vinyl-containing monomers include, but are not limited to, N-vinylamides, N-vinyllactams (e.g., N-vinylpyrrolidone (NVP)), N-vinyl-N-methylacetamide, N-vinyl-N-ethylacetamide, and N-vinyl-N-ethylformamide, N-vinylformamide, and other monomers. 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.

[0085] Acrylic-type or acrylic-containing monomers are monomers containing the acrylic group: (CH2=CRCOX), where R is H or CH3, and X is O or N, and are also known to polymerize readily, such as N,N-dimethylacrylamide (DMA), 2-hydroxyethyl methacrylate (HEMA), glycerol methacrylate, 2-hydroxyethyl methacrylamide, polyethylene glycol monomethacrylate, methacrylic acid, and mixtures thereof.

[0086] Other hydrophilic monomers that can be used in the present invention include, but are not limited to, polyoxyethylene polyols having one or more of their terminal hydroxyl groups replaced with a functional group containing a polymerizable double bond. Examples include polyethylene glycol, ethoxylated C1-20 alkyl glucoside, and ethoxylated bisphenol A reacted with one or more molar equivalents of an end-capping group such as isocyanatoethyl methacrylate, methacrylic anhydride, methacryloyl chloride, or vinylbenzoyl chloride to produce polyethylene polyols having one or more terminal polymerizable olefin groups attached to the polyethylene polyol via a linking moiety such as a carbamate or ester group. Other suitable hydrophilic monomers will be apparent to those skilled in the art.

[0087] In some exemplary, non-limiting 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 other embodiments, the hydrophilic monomer comprises at least one of DMA, HEMA, NVP, and N-vinyl-N-methylacrylamide, and mixtures thereof. In other embodiments, the hydrophilic monomer comprises DMA and / or HEMA.

[0088] The hydrophilic component(s) (e.g., hydrophilic monomer(s)) can be present in a wide range of amounts depending on the particular balance of properties desired. In some embodiments, the amount of hydrophilic component(s) is up to 60% by weight, e.g., 5-40% by weight, based on all reactive components.

[0089] A hydrophobic silicone-containing component (or silicone component) can be considered to contain at least one [—Si—O—Si] group in a monomer, macromer, or prepolymer. In some embodiments, the Si and bonded O are present in the silicone-containing component in an amount greater than 20% by weight, for example, greater than 30% by weight of the total molecular weight of the silicone-containing component. Useful silicone-containing components include polymerizable functional groups such as acrylate, methacrylate, acrylamide, methacrylamide, N-vinyl lactam, N-vinyl amide, and styryl functional groups.

[0090] Additionally, in some exemplary but non-limiting embodiments, crosslinking monomers may be used alone or in combination and may include ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, glycerol trimethacrylate, polyethylene glycol dimethacrylate (polyethylene glycol having a molecular weight of, for example, up to 400), and other polyacrylate and polymethacrylate esters. The crosslinking monomers may be used in conventional amounts, for example, 0.1 to 5 parts by weight, preferably 0.2 to 3 parts by weight, per 100 parts by weight of the polymerizable mixture.

[0091] Another monomer that may be used in some exemplary, non-limiting embodiments includes methacrylic acid, which can be used to affect the amount of water the hydrogel can absorb at equilibrium. Methacrylic acid is typically used in amounts of 0.2 to 8 parts by weight per 100 parts of a hydrophilic monomer, such as HEMA. Other monomers that may be present in the polymerization mixture include methoxyethyl methacrylate, acrylic acid, and the like.

[0092] In some exemplary, non-limiting embodiments, the polymerizable mixture includes hydroxyethyl methacrylate (HEMA) or hydroxyethyl acrylate (HEA) monomers, preferably hydroxyethyl methacrylate (HEMA) monomers.

[0093] In some exemplary, non-limiting embodiments, the polymerizable mixture includes a methacrylate or acrylate monomer that is not a hydroxyethyl methacrylate or hydroxyethyl acrylate monomer.

[0094] In some exemplary non-limiting embodiments, the polymerizable mixture includes a reactive silicone monomer or oligomer.

[0095] In some further exemplary and non-limiting embodiments, the polymerizable mixture after polymerization can provide a polymer that is not water-swellable, e.g., a polymer that cannot take up more than 2% water by weight.

[0096] 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 high temperatures, such as lauryl peroxide, benzoyl peroxide, isopropyl percarbonate, azobisisobutyronitrile, and photoinitiator systems such as aromatic α-hydroxyketones, alkoxyoxybenzoins, acetophenone, acylphosphine oxides, bisacylphosphine oxides, and tertiary amine plus diketones. Illustrative examples of photoinitiators are 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-propan-1-one, bis(2,6-dimethoxybenzoyl)-2,4-trimethylpentylphosphine 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 a combination of camphorquinone and 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® (available 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 and other photoinitiators that can be used are those disclosed in Volume I Initiators for Free Radical Cationic & Anionic Photopolymerizatioris, 2nd Edition, by JV Crivello & K. Dietliker, edited by G. Bradley; John Wiley and Sons; New York; 1998.

[0097] In some embodiments, the polymerization initiator is included in the polymerizable mixture in an amount capable of initiating polymerization of the polymerizable mixture, e.g., 0.1 to 2 wt. %. Polymerization of the polymerizable mixture can be initiated using heat, visible or ultraviolet light, or other energy sources, depending on the polymerization initiator used. Alternatively, in some embodiments, initiation can be performed without a photoinitiator, for example, using an electron beam. However, if a photoinitiator is used, preferred initiators are bis(2,4,6-trimethylbenzoyl)phenylphosphine oxides, such as bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (Irgacure 819®) or a combination of 1-hydroxycyclohexylphenyl ketone and DMBAPO. In another embodiment, the method of initiation is via visible light activation.

[0098] In some embodiments, the polymerizable mixture may include one or more internal wetting agents. 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).

[0099] The internal wetting agent(s) can be present in a wide range of amounts depending on the particular parameters desired, hi some embodiments, the amount of wetting agent is up to 50% by weight, e.g., 5-40% by weight, e.g., 6-30% by weight, based on all reactive components.

[0100] Additionally, the polymerizable mixture may contain one or more auxiliary ingredients selected from, but not limited to, chelating agents, polymerization inhibitors, viscosity modifiers, surface tension modifiers, glass transition modifiers, compatibility components, ultraviolet absorbing compounds, pharmaceuticals such as ophthalmic medications, ophthalmic disinfectants, excipients, antimicrobial compounds, copolymerizable and non-polymerizable dyes, release agents, reactive dyes, pigments, and chelating agents, and combinations thereof. In some embodiments, the total amount of such auxiliary ingredients may be up to 20% by weight. Preferred embodiments may include a photoinitiator that generates reactive species upon exposure to one or more of visible light, ultraviolet light, infrared light, and infrared radiation, and may include one or more of visible light, ultraviolet light, infrared light, and infrared radiation absorbing moieties.

[0101] The polymerizable mixture can 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 together with an inert diluent to form the polymerizable mixture. Such diluents can control the expansion of the formed ophthalmic device upon hydration, aid in the solubility of the components, and adjust the glass transition temperature. Other embodiments may omit the inert diluent.

[0102] Suitable diluent classes include, but are not limited to, alcohols having 3 to 20 carbon atoms, amides having 10 to 20 carbon atoms derived from primary amines, ethers, polyethers, ketones having 3 to 10 carbon atoms, and carboxylic acids having 8 to 20 carbon atoms. As the number of carbons increases, the number of polar moieties also increases, which may 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.

[0103] 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, tripropylene methyl ether (TPME), butoxyethyl acetate, mixtures thereof, and the like.

[0104] In some embodiments, the diluent is selected to have some solubility in water, hi 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-hexamethoxy-1-tetradecanol, mixtures thereof, and the like. Esters of alcohols, such as borate esters of alcohols, are other embodiments of diluents.

[0105] In some embodiments, the preferred amount of diluent is typically up to 60% by weight, such as 10-60% by weight, for example, 20-50% by weight, based on the complete polymerizable mixture.

[0106] In another aspect, in some embodiments, the polymerizable mixture comprises one or more crosslinkers in an amount of 0.5 to 5.0 wt. %, one or more non-reactive diluents (polyhydric alcohols, esters of polyhydric alcohols, or ethers of polyhydric alcohols, e.g., glycerol and glycerol esters) in an amount of 0 to 60.0 wt. %, and one or more polymerization inhibitors in an amount less than 100.0 ppm, preferably less than 50.0 ppm, based on the weight of the polymerizable mixture. The viscosity of the polymerizable mixture can also play an important role, typically 1 to 25 cP, e.g., 2 to 15 cP, and especially 3 to 10 cP, although other viscosities are within the scope of the invention.

[0107] As mentioned 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 limits (0.05%, 0.1%, 0.2%, etc.) are given for practical reasons, and it is quite possible to achieve even lower concentrations.

[0108] The oxygen content of the polymerizable mixture can be adjusted to a desired level (X) by exposing the polymerizable mixture (previously mixed under ambient atmosphere (10 mbar, 21% O by volume)) to a reduced pressure P, where P = X * 10 / 21 mbar. The reduced pressure (sometimes called "vacuum") can then be released and the oxygen-adjusted polymerizable mixture can be stored under an atmosphere having an oxygen concentration corresponding to a suitable atmosphere having an oxygen concentration of X.

[0109] In some preferred embodiments, the oxygen concentration in the controlled atmosphere in the ambiently deposited polymerizable mixture and in the substrate in contact with the polymerizable mixture is less than the equilibrium concentration of oxygen in the polymerizable mixture.

[0110] three dimensional printing equipment Deposition of multiple droplets is typically achieved by breaking a volume of polymerizable mixture into droplets and propelling the droplets in a desired direction at a predetermined velocity. In some embodiments, such generation of droplets of the polymerizable mixture and propelling the droplets in a predetermined direction at a predetermined velocity can be achieved through the operation of an additive manufacturing printhead. Such printheads are capable of simultaneous deposition of multiple droplets of liquid in either one-dimensional patterns (e.g., in the form of lines) or two-dimensional patterns. In some embodiments, the droplets are preferably in the picoliter range for additive manufacturing, e.g., about 3 picoliters to 20 picoliters per droplet, preferably in the picoliter range, such as 10 to 30 passes of the printhead over the substrate. In some embodiments, an ophthalmic lens is formed over 14 to 18 passes of the printhead ejecting droplets in a desired pattern over a receiving surface.

[0111] In some embodiments, the desired speed and precision of deposition of multiple droplets can be achieved with an additive manufacturing print head capable of simultaneously depositing two-dimensional patterns of polymerizable mixture, such that a pattern (or multiple successive patterns) of droplets of the polymerizable mixture representing an integer map (e.g., a grayscale image) of the energy transparency of a desired article (e.g., an ophthalmic lens) can be printed.

[0112] In some preferred embodiments, the dispersion and propulsion of droplets to form a two-dimensional pattern representing an integer map of energy transparency in the form of a grayscale image can be achieved in a single pass of a printhead that deposits droplets over an area at least the size of an ophthalmic device. Commercially available printheads suitable for this purpose include Fujifilm's Samba TM Printheads include, for example, the Samba, which has 2048 nozzles per module and can deposit fluid from a native drop size of 2.4 picoliters to a maximum drop size of 13.2 picoliters with a native DPI precision of 1200. TM It is a G3L print head.

[0113] The pattern of each path of droplets ejected, propelled, and deposited by the 3D printing device can be determined in relation to the desired transmittance pattern of the optical lens being formed. The shape of the optical lens being formed correlates with the transmittance pattern. For example (in the case of an ophthalmic device), inputs can be generated using data collected from measurements of a patient's eye. The data can include, for example, optical properties, surface properties, size and geometry, and observations of eye disease states.

[0114] The 3D printable model can be created using computer-aided design (CAD) software or based on a scan of the patient's eye, as a non-limiting example. Scanning the patient's eye can include collecting and analyzing digital data representing the shape and appearance of the patient's eye. Based on the collected data, a 3D model of the target ophthalmic device can be generated. The 3D printable model can be processed by software to convert the model into a grayscale image (or other energy intensity mapping) and generate a file containing instructions tailored to a particular type of droplet ejection device, such as a 3D printer, for repeatedly depositing a polymerizable mixture according to the grayscale image or other energy-transmitting pattern.

[0115] substrate The present invention provides for depositing multiple droplets of a polymerizable mixture onto the surface of a substrate, suitable materials for the substrate including one or more of glass, polyolefins such as polypropylene, polystyrene, and other smooth materials.

[0116] In some preferred embodiments, the morphology of the polymerizable mixture droplet receiving substrate represents the shape of one side of the resulting (unhydrated) ophthalmic device, for example, the substrate may include at least a portion that is arcuate or otherwise curved in a shape and size suitable for a contact lens that fits into the human eye. Similarly, the substrate may include a portion that is a relatively flat sector in a size and shape suitable for an intraocular lens that can be inserted into a human eye via surgery.

[0117] The size of the substrate is preferably adjusted to fit the required dimensions of the finished hydrated ophthalmic device. Substrates with a rotation axis can be formed by one or more of lathing, grinding, injection molding, and additive manufacturing. Substrates that are not constrained by a shape with a rotation axis can be prepared, for example, via 3D printing. Thus, the substrate can include a non-spherical optical surface shape, such as a substrate surface shape based on a replicated, modeled, or air-exposed portion of a patient's eye.

[0118] In some embodiments, to tailor the wettability of the surface of the substrate receiving the polymerizable mixture, the surface of the substrate may be pretreated with one or more of a surfactant, UV exposure, ozone exposure, and plasma treatment, or a combination of such treatments. In some preferred embodiments, the receiving surface of a glass or polymer substrate may be pretreated 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, a surfactant is included in the polymerizable mixture.

[0119] In some embodiments, the method for manufacturing an ophthalmic lens includes equilibrating the oxygen concentration in the substrate with the oxygen concentration in the controlled atmosphere. Similarly, in some preferred embodiments, the oxygen concentration in the substrate is the same as or less than the oxygen content of the polymerizable mixture deposited on the substrate.

[0120] 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 the controlled atmosphere (or a corresponding atmosphere) for, for example, at least 8 hours prior to deposition of the droplets.

[0121] In some embodiments, the substrate may only allow a limited amount of oxygen therein, and therefore, it may not be necessary to take specific precautions regarding oxygen concentration within the substrate.

[0122] In an alternative embodiment, the substrate is itself an ophthalmic device (e.g., a conventional commercially available contact lens, etc.) that is modified by the methods described herein to form a final ophthalmic device, such as an ophthalmic device modified to have one or more of different optical properties, an ophthalmic device with a modified color pattern, and an ophthalmic device with different physical properties.

[0123] CA storage, controlled atmosphere storage, gas storage In some embodiments, the ambient atmosphere in which the deposition printing described herein occurs can be controlled. The controlled ambient atmosphere can include, by way of non-limiting example, one or both of a defined range of specific gases, a defined range of particles, and a controlled wavelength of light or other energy wavelength. In some preferred embodiments, an appropriately low concentration of oxygen is achieved in the atmosphere containing the polymerizable mixture so that the oxygen content of the polymerizable mixture is appropriately controlled. In some embodiments, the receiving surface of the substrate can be contained within the controlled ambient atmosphere.

[0124] As a specific, non-limiting example, in some embodiments, the controlled atmosphere has an oxygen concentration of up to 5.0% by volume. In some embodiments, such as those including etafilcon A as the ophthalmic lens material, the oxygen concentration in the controlled atmosphere is up to 2.0% by volume, e.g., 0.01-2.0% by volume, e.g., 0.03-1.5% by volume, e.g., 0.05-1.2% by volume, e.g., 0.1-1.1% by volume, more preferably up to 1.0% by volume. The lower limits (e.g., 0.01%, 0.03%, 0.05%, etc.) are provided for practical reasons, and even lower concentrations are quite possible.

[0125] In another aspect, in some embodiments, the controlled atmosphere in which the deposition of the polymerizable mixture takes place is most conveniently at a pressure of 1.0 atmosphere (1013 mbar), which corresponds to an oxygen concentration of 21% by volume. Oxygen concentrations lower than the 21% by volume found in normal atmospheres may be suitably obtained by mixing air with another gas, for example, in some preferred embodiments, an inert gas such as one or more of nitrogen, helium, argon, or other inert gases.

[0126] In some embodiments, the controlled atmosphere may include an inert gas, such as nitrogen, mixed in a specific amount with pure oxygen. One preferred approach for a controlled atmosphere is to use nitrogen as the inert gas to replace atmospheric oxygen, thereby achieving a desired level of oxygen concentration.

[0127] The oxygen concentration may be monitored by an oxygen meter and adjusted one or more of before the additive manufacturing process, at the start of the additive manufacturing procedure, and during the manufacturing procedure, and preferably may be controlled intermittently or continuously during the process of preparing one or both of the optical element and the substrate.

[0128] Additive droplet deposition and hardening The method of the present invention involves depositing successive passes of multiple droplets of a polymerizable mixture under a controlled atmosphere onto a receiving surface, which may include one or more of a substrate, an insert, and previously deposited droplets. The droplets of the polymerizable mixture are preferably ejected from a printhead and deposited based on a two-dimensional pattern representing an energy-transmitting pattern, such as a grayscale image (or other light map representing light intensity). After deposition of the droplets of the polymerizable mixture, the droplets may be exposed to a controlled amount of actinic radiation to cause a gelation process that pins the droplets of the polymerizable mixture in place relative to the substrate.

[0129] The polymerizable mixture is typically deposited using a 3D printing device, such as the printing devices described herein. In embodiments, individual droplets have a volume of 0.5 to 50 picoliters (pL), such as 1 to 40 pL or 1.5 to 30 pL, preferably 2.0 to 15 pL.

[0130] In some embodiments, each of the plurality of droplets of polymerizable mixture is deposited on a surface relative to the substrate. The surface relative to the substrate may include one or more of the top surface of the substrate, previously deposited droplets, and articles disposed on one or both of the substrate and the previously deposited droplets of polymerizable mixture. The polymerizable mixture deposited on the previously deposited polymerizable mixture may be incorporated into the previously deposited polymerizable mixture such that a single mass of polymerizable mixture without a discernible layer is formed on the substrate. The single mass of polymerizable mixture may include multiple optical interfaces and / or sub-optical elements formed by one or more sequential steps of depositing, consolidating, melting, gelling, and pinning the polymerizable mixture.

[0131] The droplets of the polymerizable mixture deposited on the article may adhere to the article. The article may have a surface treated with a wetting agent. After contacting the receiving surface, the polymerizable mixture may then be exposed to limited actinic radiation or heat after the final deposition of successive layers of droplets to form the ophthalmic device.

[0132] In variations of the invention in which successive layers of deposited polymerizable mixture are exposed to actinic radiation (e.g., UV light), the polymerizable mixture may include a photoinitiator. In variations of the invention in which successive passes of deposited polymerizable material are exposed to heat, the polymerizable mixture may include a thermal initiator.

[0133] In some variations of the invention, the continuous pattern of polymerizable mixture is exposed to intermittent radiation (e.g., UV light) after each deposition of a layer of droplets of the polymerizable mixture. The degree of polymerization achieved by such intermittent exposure to actinic radiation is typically that required for the purpose of pinning or otherwise obtaining gelation of the polymerizable mixture. Such obtaining gelation can be used to control the movement of the deposited droplets from a first location on the receiving surface to another location on the receiving surface (and / or to control the movement of the deposited polymerizable mixture from the receiving surface).

[0134] In preferred embodiments, such controlled movement allows for limited flow of the deposited polymerizable mixture but prevents uncontrolled rearrangement of the deposited polymerizable mixture. For example, in some embodiments, controlled movement allows gravity and other natural forces, such as surface tension and / or intermolecular forces, to bond and smooth the surface of the deposited polymerizable mixture. The deposited polymerizable mixture may also integrate the deposited droplets with previously deposited polymerizable mixture, melt onto the smoothed surface of the polymerizable mixture, and then be pinned in place by a gelation process.

[0135] In some embodiments of the present invention, droplets of the polymerizable mixture are deposited onto a surface, including one or more of a substrate, an insert, and previously deposited polymerizable mixture, thereby forming a pattern of the polymerizable mixture having energy transparency characteristics based on an integer map representing the energy transparency. The integer map representing the energy transparency may comprise a two-dimensional grayscale image referenced by a software program used to control the print head and operate the print head to remove the droplets of the polymerizable mixture.

[0136] The deposited polymerizable mixture is preferably exposed to pinning actinic radiation after each pass (or after a predetermined number of passes) of the print head that deposits the polymerizable mixture, and finally exposed to curing actinic radiation after deposition of the final pass of the print head that deposits the polymerizable mixture to form the optical element.

[0137] The pass of the print head can include the print head moving relative to the substrate onto which the polymerizable mixture is to be received (the substrate and the previously deposited polymerizable mixture), and / or one or both of the print head and substrate moving relative to each other as the polymerizable mixture is deposited.

[0138] In some preferred embodiments, at least a portion of the pattern of polymerizable mixture deposited through passes after the first pass of the printhead combines and integrates with previously deposited polymerizable mixture, thereby forming a single volume of polymerizable mixture. Gravity induces limited movement of the deposited polymerizable mixture and smooths the surface of the deposited polymerizable mixture. Gravity-induced movement of the deposited polymerizable mixture can be limited by surface tension and microforces. Preferably, the single volume of polymerizable mixture is pinned and / or gelled by exposure to a limited amount of actinic radiation, thereby limiting additional movement following the smoothing effect of gravity-induced movement.

[0139] In some variations of the present invention, a series of successive printhead passes, e.g., between two and twenty (2-20) passes of the polymerizable mixture, are deposited before exposing the deposited polymerizable mixture to intermittent actinic radiation effective to pin and / or gel the deposited polymerizable mixture. Prior to exposure to intermittent actinic radiation, the deposited polymerizable mixture can undergo limited movement as a single volume of polymerizable mixture.

[0140] In some embodiments, the thickness of the polymerizable mixture deposited in a pass of the print head over the receiving surface on any particular portion of the receiving surface may be up to 50 μm (50 micrometers), but preferably up to 25 μm (25 micrometers). Some embodiments may include up to 10 μm of polymerizable mixture deposited in a single pass of the print head over the receiving surface (which may include one or more of the substrate, previously deposited polymerizable mixture, insert, and formed ophthalmic lens).

[0141] In some variations of the invention, the polymerizable mixture includes multiple photoinitiators, with the two or more photoinitiators responsive to different wavelengths of actinic radiation. This is particularly interesting when it is desirable to utilize one wavelength of UV light for intermittent exposure (pinning or gelling) and another wavelength of UV light for final curing of the deposited polymerizable mixture to form an optical element. Thus, in some variations of the invention, a first polymerization initiator is used (in conjunction with exposure to an appropriate first actinic radiation) to partially create the polymerizable mixture construct, and a second polymerization initiator is used (in conjunction with exposure to an appropriate second actinic radiation) to complete the curing process.

[0142] In addition to controlling the oxygen level in the polymerizable mixture within a desired range of oxygen content, some embodiments of the present invention include controlling the polymerization of the deposited polymerizable mixture such that the degree of polymerization of the deposited polymerizable mixture within a specific time frame after deposition is limited to the degree of gelation, stopping or substantially slowing the movement of the polymerizable mixture while allowing droplets from subsequent passes to fuse into the previously deposited polymerizable mixture and form an optical element structure with limited distortion, such that optical elements are fabricated using the processes described in this disclosure.

[0143] The process for intermittent gelation may sometimes be referred to as pinning or gelling of the deposited polymerizable mixture. In some variations of the present invention, the pinning process may include applying actinic radiation of an intensity, wavelength, and length of time suitable to cause gelation, such as, for example, applying ultraviolet (UV) light to a UV-curable polymerizable mixture and / or ink (UV ink). The actinic radiation wavelength may be matched to the photochemical properties of the polymerizable mixture and / or UV ink used in the manufacturing process. The actinic radiation may be any radiation that produces the desired photochemical activity, which in this case is polymerization of the polymerizable material.

[0144] As a result of intermittent gelation, the deposited polymerizable mixture and / or ink droplets move to a higher viscosity state but do not fully cure. Variations of the present invention that involve pinning or gelling (or gelation) have an enhanced ability to control the flow and morphology of the deposited polymerizable mixture, which in turn provides high optical quality to the optical element formed through the final curing of the deposited polymerizable mixture. For example, sufficient flow is preferred to allow gravity and / or other natural forces, such as surface tension and microforces, to smooth the surface of the gelled polymerizable mixture but not significantly change the shape of the optical element. In some variations, other forces, such as centrifugal force, may be used to shape the surface.

[0145] The gelation and curing process can be modified based on the selection and / or concentration of one or more of the photoinitiator, crosslinker, actinic radiation source (e.g., UV light source), actinic radiation intensity, and exposure duration. Examples of actinic radiation sources can include light emitting diodes (LEDs) or light bulbs, lasers, and other emitters.

[0146] In some specific embodiments, the polymerizable mixture may contain two photoinitiators that absorb energy at two different wavelengths. The polymerizable mixture is used with a corresponding UV LED light source (e.g., 365 nm and 400 nm). One initiator may be present in a concentration that can initiate gelation of the polymerizable mixture but is insufficient to complete polymerization. This allows individual deposits of the polymerizable mixture to reach the same (or similar) relative degree of conversion before final curing. Final polymerization of the entire article formed by multiple subsequent deposits and pinning of the polymerizable mixture (e.g., an optical element) may be performed in a separate step using actinic radiation energy or a different photoinitiator / UV LED light combination (e.g., actinic radiation energy of a second photoinitiator, or a third photoinitiator, etc.) to produce the uniform polymer network required for optical functionality.

[0147] Alternatively herein, a thermal initiator active above Tg may be used in place of, or in addition to, a second (or other) photoinitiator to complete the cure of the deposited polymerizable mixture. The present invention also provides that if the oxygen content of the deposited polymerizable mixture is not controlled throughout the deposition process steps and during the final cure step, oxygen inhibition effects can adversely affect the uniformity of the polymer network and lead to the production of an incompletely cured polymer and therefore a device with a sticky surface.

[0148] In some embodiments, the polymerizable mixture is deposited on a curved surface according to the methods described herein, and the first or multiple depositions may be deposited on the curved surface as a pattern of droplets of the polymerizable mixture, the pattern of droplets comprising a volume and distribution that allows surface tension to maintain the pattern of droplets of the polymerizable mixture with limited flow or other movement until partially hardened in a gelation process, thereby fixing the deposited polymerizable mixture in place (and restricting flow).

[0149] Subsequent deposition of additional droplets from the print head can fill in the spaces left by the first deposition or subsequent layers until the surface of the receiving substrate is completely covered with the polymerizable mixture and the deposited polymerizable mixture establishes a foundation for building optical elements. An alternative to dot patterns includes depositing droplets to form very thin layers (e.g., 1 micron to 8 microns) and building optical elements on such very thin layers using the processes disclosed herein.

[0150] In some embodiments, it is useful to isolate the monomers comprising the print head from exposure to actinic radiation, such as ultraviolet radiation, to prevent premature gelation or polymerization of the monomers within the print head, which could render the print head inoperable or operable at a reduced performance level. Isolation from actinic radiation is particularly important when using reactive monomers with low levels of inhibitors and / or when using the print head in an environment with low oxygen levels. Isolation can be achieved, for example, through physical separation of the print head and actinic radiation.

[0151] To achieve simultaneous printing and pinning of materials to stop or slow the movement of the deposited ink or polymerizable mixture once deposited, some embodiments of the present invention include an apparatus operative to separate the actinic radiation source (e.g., UV light source) from the print head to essentially eliminate or substantially reduce the possibility of gelling / polymerization of the polymerizable mixture within the print head. Isolating the print head from the actinic radiation source and controlling both the oxygen level and the movement of the polymerizable mixture allows for the fabrication of precise shapes and optical devices without artifacts within the matrix that adversely affect the optical performance of the final fabricated lens.

[0152] In some embodiments, washing the gelled deposited polymerizable mixture with a solvent or water, for example to remove excess monomer, is preferred after multiple deposition and gelling processes of the polymerizable mixture are completed, but before the final curing process is performed.

[0153] 1, a side view 120A of a multifocal lens 120 is shown having multiple optical interfaces that may result from sub-optics 121, 122, 123, and 124 along a given optical path 128 through the multifocal lens 120. Each optical interface that may result from the sub-optics 121, 122, 123, and 124 has an associated optical power such that a person (or automation) viewing through the multifocal lens 120 can see an image transmitted as an energy pattern within the visible light spectrum modified by one of the sub-optics 121, 122, 123, and 124. Typically, the modification of an image transmitted as energy within the visible light spectrum is described as an optical power such as minus 2.0 diopters, plus 1.25 diopters, or 0 diopters (sometimes referred to as a flat lens). The optical interfaces resulting from the sub-optics 121, 122, 123, 124 may be unique within the multifocal lens 120 or may be repeated in different sub-optics 121, 122, 123, 124. A diopter may generally be considered to refer to a unit of refractive power equal to the reciprocal of the focal length (usually in meters) of a given sub-optic 121, 122, 123, 124.

[0154] A person looking through the multifocal lens 120 along optical paths 125-128 may neurologically select an image modified by one or more of the sub-optical elements 121, 122, 123, 124.

[0155] In healthy individuals with fully functioning eyes, observing distant and near objects changes the state of their ciliary muscles. When viewing a distant object, the ciliary muscles relax, the zonular fibers tighten, and the lens flattens. In this state, the refractive power of a person's natural lens is sufficient to form a focused image of the object on the retina. To focus on near objects, the internal structures of the eye adapt through a process of accommodation, which may be called the accommodation reflex. The accommodation reflex typically involves one or more of three responses: a) an increase in lens curvature, b) pupil constriction, and c) ocular convergence. During normal vision in a person with optimal ocular health, accommodation cycles through the three responses. The cycling rapidly presents multiple optical variations of energy in the visible light spectrum to the retina and optic nerve. The person neurologically confirms the presented images for conscious brain registration. Normal biological progression (such as aging) limits each person's accommodation reflex, thus limiting the optical variations of energy in the visible light spectrum presented to the person's optic nerve.

[0156] The present invention simultaneously presents multiple optical variations of energy in the visible light spectrum to the optic nerve. Simultaneous presentation of multiple optical variations of energy in the visible light spectrum to the optic nerve does not exactly replicate the human accommodation reflex because the simultaneous presentation of multiple optical variations of energy does not involve physical movement. However, the simultaneous presentation of multiple optical variations of energy in the visible light spectrum to the optic nerve allows the brain to neurologically select the image to be presented as an image for conscious alignment, in a manner very similar to the neurological selection of an image from a series of images normally presented in a visual process.

[0157] At a high level, a normal reflex pathway in a healthy individual with functional accommodation can generally be thought of as involving the optic nerve, visual and frontal cortices, the oculomotor and accessory oculomotor nuclei, and the oculomotor nerve (CNIII). When accommodation is required, the optic nerve sends an initial impulse via the lateral geniculate body and optic radiation to the primary visual cortex. From here, the impulse travels via the visual association cortex to the accessory / Edinger-Westphal nucleus of the oculomotor nucleus in the midbrain.

[0158] The action of the ciliary muscle is directed by parasympathetic nerve fibers originating in the accessory / lumbar Edinger nucleus of the oculomotor nucleus in the midbrain. Contraction of this muscle relaxes the zonular fibers, causing the lens to relax. As the lens relaxes, its curvature increases and it becomes rounder. In this way, the refractive power of the natural crystalline lens increases, allowing it to create a sharply focused image of nearby objects on the retina. The multifocal lenses provided herein allow for the reduction of mechanical movements involved as part of the accommodation reflex of a fully functioning healthy eye by simultaneously presenting multiple images to the retina and allowing the neurological confirmation of the image that a person is cognitively processing at a given moment.

[0159] Referring to top-down view 120b, in some embodiments, multiple distinct sub-optical elements 121-124 are formed by an additive manufacturing process that repeatedly applies a pattern of droplets (shown as a spherical pattern) having different center point 132 locations. The sub-optical elements 121-124 may be spherical or aspherical and may use the center point 132 or other calculated locations for alignment. As shown, the offset of each center point is exaggerated to emphasize the relative positions of the distinct sub-optical elements 121-124. In some exemplary embodiments, the offset may be between 100 nanometers and 1000 nanometers, preferably between 400 nanometers and 600 nanometers, or between 40 microns and 60 microns.

[0160] Referring now to FIG. 1A, a schematic diagram illustrates an example of an apparatus and underlying software forming an additive manufacturing system 100, the software executing which operates the apparatus. As illustrated, the additive manufacturing system 100 includes one or more additive manufacturing printing devices 101-102 operable to deposit droplets 110 of a polymerizable mixture 103 in a pattern of energy intensity and / or energy transparency (e.g., a grayscale pattern) onto a receiving surface 103a supported by a substrate 104. Deposition of the droplets 110 may be achieved, for example, by ejecting a first volume of the polymerizable mixture 110a in the form of droplets in a predefined pattern. The receiving surface for the droplets 110 contained in the volume of polymerizable mixture 110a may include one or both of the receiving substrate 104 and previously deposited polymerizable mixture 103. Additional volumes of the polymerizable mixture 110A may be added for second, third, and any desired number of additional depositions, such as 12-22 volumes of the polymerizable mixture 110A.

[0161] The receiving portion 104a of the substrate 104 may be smooth or arcuate in such a way that it is suitable as the back curve of a contact lens. The receiving surface 103a may include one or both of the designated receiving portion 104a of the substrate 104 and the previously deposited polymerizable mixture 103.

[0162] One or more actinic radiation sources 105 and 106 (which may include LEDs emitting energy at the same or different wavelengths) receive control commands from one or more controllers 113. The controller includes a processor in logical communication with executable software commands stored in digital storage. The executable software may be executed in response to the commands to operate the actinic radiation sources and may also control the relative movement of the additive manufacturing printing devices 101-102 and the receiving surface 103a.

[0163] Some variations of the present invention include an enclosure 114 having one or more ports 107 and 108 for providing a controlled atmosphere 109 within the enclosure 114. The enclosure 114 may contain an atmosphere that is ambient to and contains one or more of the substrate 104, the printing devices 101-102, the polymerizable mixture from the deposited polymerizable mixture 103 built up on the substrate (arranged to form an ophthalmic lens, such as a contact lens), and the actinic radiation sources 105-106.

[0164] In some embodiments, the substrate 104 may be positioned proximately below at least one of the 3D printing devices 101-102 (as used herein, "proximate" refers to a distance suitable for dispensed droplets to be ejected from the printing devices 101-102 and accurately positioned on the substrate). The "below" or "under" relationship may derive from the direction of gravity. The printing devices 101-102 operate to dispense droplets of the polymerizable mixture 110 onto a receiving surface 103a. The receiving surface 103a may include one or more of the surface of a receiving portion 104a of the substrate 104, the surface of previously deposited polymerizable mixture 103, and the receiving portion of an insert such as a rigid lens or electronic device. The droplets are deposited in a pattern that replicates an energy-transmitting pattern, such as a grayscale image. Successive depositions of the pattern aggregate to form a volume of the polymerizable mixture in the desired shape of the target optical element (see, for example, Figures 4-5).

[0165] After applying droplets of the polymerizable mixture 110 to the receiving surface 103a to form a volume of the polymerizable mixture 103, the polymerizable mixture may be exposed to a first dose (frequency, intensity, and length of time) of actinic radiation (which is within a first wavelength range, for a first time duration, and at a first intensity (e.g., ultraviolet light or blue light, etc.). In some embodiments, the first dose of actinic radiation may be delivered to the deposited polymerizable mixture via a first actinic radiation source 105. Final curing can be achieved by exposing the assembled polymerizable mixture to a second dose of actinic radiation (comprising a second wavelength range, a second time duration, and a second intensity), which can be sourced from the same actinic radiation source 105 or a different actinic radiation source 106. Final curing enables a molded article. The formed article, such as an ophthalmic lens 111, can be removed from the substrate.

[0166] In some variations of the present invention, the final curing process step may additionally be carried out in an environment having a controlled temperature, e.g., a temperature elevated above ambient room temperature and / or maintained within a specified range.

[0167] According to some embodiments, the first print head 101 of the system 100 may provide a first polymerizable mixture, and the second print head 102 may provide a second polymerizable mixture that may be compositionally identical or different from the first polymerizable mixture. One or both of the polymerizable mixtures may include a functional additive or a non-polymerizable mixture (e.g., a functional additive or a solvent containing a functional additive).

[0168] Ambient conditions within system 100 may be controlled, particularly with respect to atmospheric gas (e.g., oxygen) content within controlled atmosphere 109. Additionally, in some embodiments, one or more of temperature, ambient light, amount of particles, size of particles, circulation or other ambient atmosphere movement, and virtually any variable that may affect one or more of the movement of unpinned and unpolymerized deposited polymerizable mixture, polymerization of the deposited polymerizable mixture, and shape of the device formed by polymerization of the deposited polymerizable mixture may be controlled.

[0169] Provided that substrate 104 is capable of transmitting or is transparent to actinic radiation, actinic radiation sources 105 and 106, both, or either individually or in alternative combinations, may be positioned below substrate 104 or at an angle relative to substrate 104, similar to that shown in Figure 1. Additionally, shutters or other actinic radiation shields may be positioned on or above the sides of the receiving surface, the shutters or other actinic radiation shields being positioned and operative to protect the print head from actinic radiation or other actinic radiation conditions.

[0170] The nature of the surrounding gaseous environment can be controlled, for example, by the use of nitrogen gas purging through inlets 107-108. Purging can be performed to increase or decrease the oxygen partial pressure to a predetermined level.

[0171] 1B, in some embodiments, different sub-optical elements 121-124 may be formed by ejecting the same pattern of droplets during multiple passes of the print head 101 relative to the receiving substrate 104, with a tilt 129 of the print head 101 relative to the receiving substrate 104 introduced. A pass of the print head 101 relative to the receiving substrate 104 may include movement of one or both of the print head 101 and the receiving substrate 104.

[0172] In other embodiments, the tilt 129 is introduced via software adjustment to the pattern of deposited droplets. Additionally, in some embodiments, the droplet pattern may be modified based on corneal topography, which may be measured, for example, with a SW-6000 Corneal Topograph by Suoer or an Atlas Corneal Topograph by Zeiss.

[0173] Preferably, the tilt 129 is applied after the print head 101 completes a pass relative to the receiving substrate 104. The tilt 129 may include, by way of non-limiting example, approximately 500 nanometers (or 50 microns) of movement, plus or minus 20%. The tilt mechanisms 130-131 may include servos, gimbles, or other electromechanical or mechanical devices capable of precise movement.

[0174] Referring now to FIG. 1C, a graph 133 illustrates an exemplary change in optical property 135 versus the amount of tilt 136 of a given pattern from the center point position 132.

[0175] Referring now to FIG. 1D, a schematic diagram shows print head 101 relative to substrate 104 and dispensed droplets 110 of a polymerizable mixture in the presence of an actinic radiation source 105. One or both of print head 101 and substrate 104 are in mechanical communication with respective actuators 141-142. Substrate camber actuator 141 may operate through that mechanical communication to provide a tilt or tilt to the substrate relative to the stream of dispensed droplets 110 and print head 101. Similarly, print head camber actuator 142 may operate through mechanical communication with print head 101 to provide a tilt or tilt to print head 101 relative to substrate 104 or other receiving surface (e.g., potentially pinned pre-deposited droplets of polymerizable mixture, or pre-polymerization).

[0176] 1E, there is a printhead camber actuator 142 which may include a servo 141-142 or multiple servos 141-142 working together to provide camber movement or tilt to one or both of the substrate camber actuator 141 and / or printhead 101. The schematic depicts the servo as a gimble to represent multi-directional movement capability, although any type of electromechanical or electrical device that provides the appropriate movement may be used, for example, a shape memory alloy for other electroactive materials.

[0177] Referring now to Figure 2, a schematic diagram illustrates several alternative aspects that may be incorporated into a 3D additive manufacturing system 200. Some of the same reference numbers as in Figure 1 are used (e.g., 3D print heads 101-102, actinic radiation sources 105 and 106, substrate 104, enclosure 114 having one or more ports 107 and 108, and a controlled atmosphere surrounding the deposited polymerizable mixture 110). Additionally, the embodiment illustrated in Figure 2 includes an oxygen sensor 204, a gate 205 for moving components in and out of enclosure 114, a UV blocking screen 112, and an actuation structure 203 (e.g., a belt drive or stepper motor linear drive) configured to provide movement relative to the substrate 104 and one or more 3D print heads 101-102 and / or one or more actinic radiation sources 105-106.

[0178] The illustrated 3D printing system 200, as shown in FIG. 2, is similar to that of FIG. 1 and also includes one or more actuators 201-203 configured (and operative) to provide relative movement between the substrate 104 and one or more of the 3D print heads 101-102, actinic radiation sources 105-106, and, in some embodiments, an obstruction screen 112 and / or enclosure. In some embodiments, the print head actuator 201 is configured (and operative) to move the one or more print heads 101-102 relative to the substrate 104. Similarly, the radiation source actuator 203 is configured (and / or operative) to move the one or more actinic radiation sources 105-106 relative to the substrate 104. The substrate actuator 203 is configured (and / or operative) to move the substrate 104 relative to one or both of the print heads 101-102 and actinic radiation sources 105-106. A belt drive 203A is illustrated as actuating structure 203, and stepper motor tracks are illustrated as actuating structures 201-202, although other devices and apparatus are within the scope of the invention. Actuating structures 201-203 may be synchronized such that relative motion between one or more of substrate 104, print heads 101-102, and actinic radiation sources 105-106 can be coordinated with deposition of polymerizable material 110 from print heads 101-102.

[0179] The processes presented herein may be performed on the systems 100, 200 described to form optical elements 211. The processes may include operation of one or more printheads 101-102 having a first printhead 101 that dispenses droplets 110 of a first polymerizable mixture and one or more additional printheads 102 that dispense droplets 110a of a composition that may include the first polymerizable mixture, a second polymerizable mixture compositionally different from the first polymerizable mixture, and a non-polymerizable material or mixture.

[0180] In some embodiments, one or more of the first polymerizable mixture, the second polymerizable mixture, and the non-polymerizable mixture comprises one or more functionally active substances, e.g., substances in dissolved form.

[0181] In this disclosure, ophthalmic devices (and / or contact lenses) are used for purposes of illustration and discussion, however, the principles are generally applicable to the formation of manufactured articles, and the teachings presented may be broadly used in any optical element (or other article) where precise dimensions, optical properties, and / or similar uniform polymer properties are desirable, such as, for example, intraocular lenses.

[0182] According to the present invention, in some embodiments, the polymerizable mixture is delivered at high speed in the form of extremely small droplets, typically 1-15 picoliters in volume, through a gas atmosphere with a relatively high surface-to-volume ratio. A large number of droplets (estimated at 1.5-9 million) is required to form a 25 mg lens. Several factors may be considered when delivering each droplet to the appropriate location during fabrication. These factors may include, but are not limited to, one or more of: exposure of the droplet to ambient process conditions; the thickness of the material layer obtained when the droplet impacts the surface containing the substrate and one or both of the previously deposited polymerizable mixture; interactions with the substrate and / or the receiving surface containing the previously deposited polymerizable mixture, such as wetting the receiving substrate surface and merging with the previously deposited polymerizable mixture; the effects of impacting droplets; pinning via exposure time to actinic radiation and / or atmospheric gases between subsequent droplet layers of the polymerizable mixture; and curing / polymerization of the deposited polymerizable mixture.

[0183] During the additive manufacturing process, there is a significant opportunity for the polymerizable mixture to be exposed to (and pick up) ambient gases, such as oxygen, from one or more of the ambient process atmosphere (sometimes referred to as a controlled atmosphere), the receiving substrate surface, and previously deposited droplets of the polymerizable mixture. If such factors are not precisely controlled, the surface and bulk properties (including optical properties) of the resulting ophthalmic lens will be adversely affected.

[0184] The effects of oxygen are particularly severe 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 these materials, variations caused by oxygen exposure are more evident in the final cured lens after the lens has absorbed water. Therefore, in preferred embodiments, exposure to oxygen can be considered to have a negative effect.

[0185] Typically, the surface or skin portion of a lens formed with more oxygen contains more polymer network defects than the bulk portion, allowing more water to be absorbed in the oxygen-rich regions. The resulting distortions in these skin regions typically adversely affect overall mechanical properties (e.g., modulus, tensile strength, elongation), optical properties (e.g., optical transmittance, refractive index), shape, and part-to-part reproducibility.

[0186] The present invention teaches the control and adjustment of the oxygen content of the polymerizable mixture relative to the oxygen content of the controlled atmosphere (as described herein) to control the effects of oxygen to the extent that the properties of the formed optical element are not significantly affected.

[0187] In these embodiments, which involve the formation of ophthalmic devices (e.g., contact lenses, intraocular lenses, and spectacle lenses), the ability to create an optical prescription is highly dependent on the precise shape of the curved surface. Creating these necessary surfaces on these and other non-ophthalmic optical elements can be achieved using the principles claimed in this invention, thus enabling the advantages of using 3D deposition printing, such as simplicity, efficiency, more freedom in design, lower time requirements, and cost.

[0188] In some embodiments, the effect of oxygen in the polymerization process and the resulting effect of oxygen on the properties of the formed item are eliminated or substantially reduced. This allows for improved control of the post-deposition movement of the polymerization mixture during the formation of the polymer matrix layer. This can be important in creating curved, arbitrary, or irregular surfaces or shapes, and can be important when creating complex optical devices that require precisely curved surfaces, including surfaces incorporating multiple arcuate sections. Thus, the combined effect of overcoming oxygen inhibition and controlling the movement of the polymerization mixture in optical product applications is likely to reduce or even eliminate optical artifacts and distortions.

[0189] In some embodiments, the present invention provides apparatus and methods for operating an apparatus for three-dimensional depositional manufacturing of ophthalmic devices in which multiple droplets of a polymerizable mixture are deposited on the surface of a substrate (and / or previously deposited polymerizable mixture) under a controlled atmosphere, thereby forming a layer of the polymerizable mixture into a pattern that replicates an energy transparency map (e.g., a grayscale image).

[0190] In some embodiments of the present invention, the oxygen concentration in the polymerizable mixture may be adjusted relative to one or more of the oxygen concentration of the controlled atmosphere to which the polymerizable mixture is exposed, the oxygen concentration of other parts of the environment (e.g., the substrate receiving the droplets of the polymerizable mixture, etc.) so that transfer of oxygen from one source to another is avoided or at least inhibited to an extent that is not significant to polymerization of the polymerizable mixture.

[0191] Release of Ophthalmic Device from Substrate and Post-Processing Following the performance of a sufficient deposition and curing process of the polymerizable mixture 103 to form an optical element 211 (e.g., an ophthalmic device), the optical element 211 is typically released from the substrate. The polymerizable mixture 103 deposited in a specific pattern to form the optical element 211 is preferably sufficiently physically bonded to the substrate 104 during preparation of the optical element 211 to prevent undesired movement relative to the substrate 104, but the polymerizable mixture 103 should not be so tightly bonded that removal of the optical element 211 from the substrate 104 damages the optical element 211. For example, in some embodiments, care must be taken to avoid the formation of covalent bonds between the polymerizable mixture 103 and the substrate 104 during preparation of the optical element 211, including curing the polymerizable mixture 103.

[0192] The ophthalmic device 211 may be released (or otherwise removed) from the substrate 104 by physical means, allowing the optical element 211 to be manipulated in a variety of ways. For example, the optical element may be manipulated via one or more of washing the optical element 211 to remove by-products, soaking the optical element 211 in buffered saline, or staining, marking, and packaging the optical element 211. In some variations 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 water and a solution, such as buffered saline, sufficient to swell the optical element 211. The swelling facilitates release of the optical element 211 from the substrate 104. The solution may also include one or more release agents. The release agent may include a compound or mixture of compounds that, when combined with water, reduces the time required to release the optical element 211 from the substrate 104 compared to the time required to release such an optical element 211 using an aqueous solution that does not include the release agent.

[0193] Although typically preferred, it is not strictly necessary that curing of optical element 211 be completed before it is released from substrate 104 .

[0194] In some embodiments, after curing, the optical element 211 undergoes one or more extraction process steps to remove unreacted components from the optical element 211. The extraction process steps can be performed using one or more of a conventional extraction fluid, an organic solvent, an alcohol, or water (or an aqueous solution such as buffered saline). In various embodiments, extraction can be achieved, for example, by immersing the lens in an aqueous solution or by exposing the lens to a stream of aqueous solution. In various embodiments, extraction can also include, for example, one or more of heating the aqueous solution, agitating the aqueous solution, increasing the level of a release aid in the aqueous solution to a level sufficient to cause release of the lens, mechanical or ultrasonic agitation of the lens, and incorporating at least one leaching aid in the aqueous solution to a level sufficient to facilitate adequate removal of unreacted components from the lens. The above can be performed in a batch or continuous process, with or without the addition of heat, agitation, or both. The ophthalmic device can also be sterilized by known means, such as, but not limited to, autoclaving and radiation sterilization. Sterilization can occur before or after packaging the optical element 211 in an appropriate storage container, preferably after packaging. In some preferred embodiments, the optical element 211 is packaged in an aqueous solution.

[0195] For optical elements 211 formed from hydrogel, packing may include packing in physiological saline containing approximately 0.9% sodium chloride and a suitable buffer, such as a phosphate or borate buffer system. Additionally, the packing solution may include one or more functionally active substances, including biologically active substances.

[0196] The aqueous solution may also contain additional water-soluble ingredients, such as release agents, wetting agents, lubricants, active pharmaceutical ingredients, vitamins, antioxidants, and nutraceutical ingredients, or combinations thereof. In some embodiments, the aqueous solution contains less than 10% by weight, and in other embodiments, less than 5% by weight, of an organic solvent, such as isopropyl alcohol, and in other embodiments, 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.

[0197] In some embodiments, the aqueous content of the hydrogel optical element 211 comprises at least 30% water by weight, in some embodiments at least 50% water by weight, in some embodiments at least 70% water by weight, and in other embodiments at least 90% water by weight.

[0198] In a variant of the invention, the polymerizable mixture 110 comprises a hydroxyethyl methacrylate (HEMA) monomer, and the method comprises a subsequent step of swelling the optical element, preferably an ophthalmic device, in water, whereby the optical element obtains a water content of 10 to 80% by weight, preferably 35 to 70% by weight.

[0199] In an embodiment, the polymerizable mixture 110 includes acrylate monomers that are free of HEMA monomers, and the method includes the next step of swelling the optical element, preferably an ophthalmic device, in water, whereby the optical element obtains a water content of 10-80% by weight, preferably 35-70% by weight.

[0200] In an embodiment, the polymerizable mixture 110 comprises a reactive silicone precursor, and the method includes a subsequent step of swelling the optical element, preferably an ophthalmic device, in water, whereby the optical element obtains a water content of 5 to 70% by weight, preferably 10 to 50% by weight.

[0201] Novel Ophthalmic Devices The methods and apparatus of the present invention enable the formation of optical elements 211 having one or more designs, by way of non-limiting example, contact lenses or intraocular lenses having non-rotationally symmetric surfaces with corresponding optical corrections including very steep radii of curvature and very high spherical and cylindrical corrective components, contact lenses or intraocular lenses that include multiple spherical and cylindrical corrections within the same lens as opposed to a single spherical correction that reflects the power distribution map of the eye and not just the average correction of the refractive power from a phoropter or refractometer, and contact lenses or intraocular lenses that (due to their non-rotational symmetry) can correct optical abnormalities resulting from poor surgical outcomes of PRK or LASIK or LASEK surgery.

[0202] Iterative Grayscale Image-Based Additive Manufacturing Referring now to FIG. 3, an exemplary energy-transmissive pattern such as grayscale image 300 may be used to generate additive manufacturing control commands for controlling the ejection of droplets of a polymerizable mixture in a pattern that replicates grayscale image 300.

[0203] For example, in some embodiments, a data map, either directly or via a conversion, represents the amount of polymerizable mixture deposited at a given location, corresponding to the data values ​​associated with pixels included in the grayscale image 300, such as an integer map. In other embodiments, the values ​​associated with pixels may be floating-point or other expressions of real integers. The data values ​​may 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 AM printhead control commands. The printhead control commands are executable to control the deposition of polymerizable mixture at locations corresponding to a pattern that replicates the grayscale image 300 pixel by pixel. For example, a data value with a relatively large digital number may correspond to a darker area of ​​the grayscale image 300 and correspond to the ejection of a greater amount of polymerizable mixture from the printhead than the ejection corresponding to a lighter area of ​​the grayscale image. A thicker deposit 301 and a greater amount of polymerizable mixture than the control command value may be assigned by converting the grayscale value at the location of the thicker deposit 301 to a printhead control command value for the thicker deposit 301. Similarly, lighter values ​​included in the grayscale may correspond to thinner deposits 304, and appropriate printhead control command values ​​may be assigned by converting the lighter grayscale values ​​to appropriate control command values ​​for the thinner deposits 304.

[0204] In some examples, thicker deposits 301 may be formed by printing a relatively greater amount of polymerizable mixture at a particular location on the receiving surface during a pass of the 3D print head, and thinner deposits 304 may correspond to printing a relatively lesser amount of polymerizable mixture at the location of the thinner deposits 304. The thicker deposits 301 may correspond to relatively darker portions of the grayscale image 300, and the thinner amounts 304 may correspond to relatively lighter portions of the grayscale image 300.

[0205] Referring now to Figure 300A, a schematic diagram illustrates an exemplary energy-transmissive pattern, such as grayscale image 300, that may be used to generate additive manufacturing control commands for controlling the ejection of droplets of polymerizable mixture in a pattern that replicates grayscale image 300. The schematic diagram illustrates a thicker deposit 301, a top surface 302, an edge profile 303, and a thinner amount of polymerizable mixture deposit.

[0206] According to the present invention, after each pass of the print head and associated deposition of the polymerizable mixture, the deposited polymerizable mixture may be allowed to "sit" for a short period during which the material is acted upon by physical forces such as gravity, surface tension, and microforces to modify the surface characteristics. Modifying the surface characteristics may include, by way of non-limiting example, one or more of leveling high and low areas formed during the deposition process, smoothing the surface of the deposited polymerizable mixture, flowing the deposited polymerizable mixture into interstitial areas, and forming uniform edges of the deposited polymerizable mixture.

[0207] Essentially, the present invention allows for the top surface 302 to be formed by physical forces present in nature, as opposed to a manufactured surface, such as a mold surface and / or a turned surface. Gravity smoothes the top surface of the deposited polymerizable mixture before it undergoes a gelation process, such as pinning by exposure to a controlled amount of actinic radiation.

[0208] In some variations of the present invention, control commands can be used to determine the number of passes of the 3D print head over the receiving surface. The number of passes of the 3D print head can be correlated to the thickness of the deposited polymerizable mixture and can also be correlated to the amount of energy transparency at specific locations of the deposited polymerizable mixture pattern. In this way, the deposited polymerizable mixture can be deposited, pinned, and finally cured in a shape and volume suitable for forming an ophthalmic lens with desired ophthalmic qualities. The deposited polymerizable mixture achieves sufficient thickness and appropriate shape by repeatedly applying the corresponding grayscale image.

[0209] In some variations of the 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 previously mentioned, in some variations of the invention, each pass of the 3D print head depositing a polymerizable mixture may be followed by exposure of the polymerizable mixture to a gelation process, such as actinic radiation, thermal activation, or the like, in an amount sufficient to partially polymerize the deposited polymerizable mixture. A curing process may be performed after the final pass of the polymerizable mixture is performed. In various embodiments, the final layer may be subjected to a pinning step and / or may move directly to a full curing process.

[0210] Curing and / or pinning can be facilitated by including one or more photoinitiators in the deposition monomers, which may include, by way of non-limiting example, initiators activated by energies of about 392 nM and 400 nM.

[0211] In some examples, an energy-transmissive pattern (e.g., a grayscale image) may be derived from an article in physical form that is processed via an optical scanning process, an image capture process, or a photography process to capture the energy-transmissive data into an electronic format, such as, for example, digital data values, which may be converted into control commands.

[0212] Some variations of the invention involve generally spherical grayscale images, where lighter values ​​are associated with thicker deposits, and different transformation protocols can therefore be assigned to different grayscale images depending on the values ​​corresponding to thick and thin deposits, respectively.

[0213] In some examples, a single grayscale image may be used to represent the desired product lens and its associated control commands, which may be repeatedly deposited with successive passes of a 3D print head, one pass following the other, until the desired optical qualities are embodied in the deposited polymerizable mixture, which may then be cured to form an article that also meets physical parameters suitable for wearing in a patient's eye.

[0214] In other examples, a series of grayscale images can be assembled to create multiple sets of control commands. The control commands can result in the deposition of different shape designs, physically creating an additive composite of images. In other examples, multiple grayscale images can be combined and processed before any processing occurs. In some examples, the combination of multiple images can be normalized to correspond to top and bottom thickness factors.

[0215] In some examples, different features such as edge profiles 303, alignment features, etc. can be programmed into the optics command protocol by adding grayscale images to the lens profile.

[0216] In some examples, the refractive elements may be designed as an array of grayscale values ​​at positions on the surface plane, with the values ​​corresponding to thicknesses or ranges of thicknesses added in the printing process. In a similar example, a constant grayscale value may be equivalent to a flat lens element with no refractive power added to any underlying structure.

[0217] In some examples, the grayscale image may be referenced from a number of file types, such as, by way of non-limiting example, one or more of JPEG, TIFF, BMP, PNG, etc., and may be used to create a control command protocol for printing a desired article, such as an ophthalmic lens article, by varying the amount of polymerizable mixture deposited at different locations, resulting in more polymerizable mixture deposition in targeted areas with thicker deposits. Printing the entire pattern may result in an article without void areas.

[0218] In some variations of the present invention, the grayscales in the image or additive combinations of images may correspond to the processing of multiple different passes of a 3D print head, where an amount of polymerizable mixture deposited at a specific location undergoes a pinning process before the next deposition pass is completed. The polymerizable mixture deposited during a printing process pass may be a monomer mixture with various included photoinitiators. One of the photoinitiators may be associated with the wavelength of actinic radiation exposure during the associated pinning process. After multiple printing passes have been processed, the entire volume of polymerizable mixture deposited on the receiving substrate may be subjected to a curing process. In some examples, the curing process may be exposure to actinic radiation of different wavelengths, exposure times, intensities, etc.

[0219] In another aspect, in some embodiments, the grayscale or energy transparent pattern may be dithered via a dithering process or algorithm prior to generating printhead control commands based on the grayscale or energy transparent pattern to generate a smoother image deposited via droplet ejection from the printhead and buildup before curing. Dithering may include, by way of non-limiting example, processes consistent with Floyd-Steinberg, Burkes, Sierra, Two Row Sierra, Jarvis, Stevenson, Arce, or other processes.

[0220] Referring now to FIG. 3B, a schematic diagram illustrates how a conventional 3D printing process might approach the manufacture of an optical lens. As shown in FIG. 3B, a lens model 310 is designed to include desired lens features. The lens model 310 is parsed into slices 312-313. Each slice may include, for example, a different horizontal segment. Each slice may then be printed layer-by-layer.

[0221] Referring now to FIG. 3C, a schematic diagram illustrates exemplary steps that may be performed in practicing the present invention. A lens model 310 is designed and includes desired lens characteristics. An energy transmission map 323 is created that represents how an energy spectrum 321 (such as, by way of non-limiting example, a portion of the light spectrum corresponding to visible light) passes through the generated lens 322. In accordance with the present invention, the energy transmission map 323 is deposited multiple times onto a receiving surface 327 as respective volumes of polymerizable mixture 325. Portions of the volumes of polymerizable mixture may combine with one or more portions of previous volumes of deposited polymerizable mixture to produce an integrated composite 326 of polymerizable mixture.

[0222] Referring now to FIG. 4 , an optical element 400 is shown in accordance with some embodiments of the present invention. The optical element 400 includes a peripheral portion 401, which may be printed or otherwise formed before the optic zone portion 402 of the optical element 400. A lens carrier portion 403 may transition between the optic zone portion 402 and the peripheral portion 401. The carrier portion 403 is preferably sized and shaped to help maintain the finished lens comfortably in place on the wearer's eye. During additive manufacturing of the optical element 400, the polymerizable mixture included in the peripheral portion 401 may be deposited and pinned, but may not be fully polymerized, before the polymerizable mixture included in the optic zone portion 402 is printed and pinned. In some preferred embodiments, the peripheral portion 401 may include a larger mass so that, as the polymerizable mixture hardens into a polymer, stresses resulting from the polymerization process do not deform the optic zone portion 402 due to the stabilizing influence of the larger mass of the peripheral portion 401.

[0223] In some embodiments, peripheral portion 401 may remain with optical element 400 or may form a pleasing edge feature. In other embodiments, some or all of peripheral portion 401 may be removed, for example, via laser trimming.

[0224] Embodiments including a higher mass peripheral zone portion 401 may be formed by a) printing or otherwise depositing a polymerizable mixture in the peripheral zone portion (generally annular for spherical lenses, and other lenses may have a corresponding peripheral shape such as elliptical or almond-shaped), b) pinning the polymerizable mixture in the peripheral zone portion 401, with pinning being preferred after each pass of the printhead-depositing monomer, or c) printing or otherwise depositing a polymerizable mixture in the optical zone, pinning the polymerizable mixture in 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.

[0225] 5, a profile cutaway view is shown having a peripheral portion 501, an optical zone 503, and a carrier portion 502 supporting an optical insert or cap 504. In some embodiments of the present invention, the peripheral portion 501 may comprise a higher mass than the carrier portion 502 and / or the optical zone 503 portions of the lens 500.

[0226] Generate axial thickness profile The front radius of curvature (RF) of a hydrated contact lens is generated from the thick lens equation using the lens power in air (P), lens refractive index (n), center thickness (CT), and back radius of curvature (RB).

[0227] Formulas for thick lenses may include, by way of non-limiting example, the following: The effective focal length for a principal plane of a thick lens is given by:

[0228]

number

[0229] The distance from the vertex of the lens to the principal plane is given by:

[0230]

number

[0231] For ophthalmic lenses, exemplary variables may include:

[0232]

number

[0233] The anterior and posterior optical zone surfaces may be generated from the anterior and posterior radii of curvature and central thickness of other optical elements of the ophthalmic lens.

[0234] An exemplary surface for a −3.0D design with a center thickness of 0.1008 mm, a back surface radius of curvature of 9.1 mm, and a refractive index of 1.4055 is shown in FIG.

[0235] In some embodiments, the axial thickness profile may be generated by subtracting the back position from the front position of a plurality of radial positions.

[0236] The ratio of hydrated to non-hydrated lenses may vary based on the lens material, with hydrated lenses being 1.4 times larger in each direction than non-hydrated lenses. Thus, the non-hydrated axial thickness profile may be approximately 1.4 times smaller (as used herein, the term may be within 10% of the stated amount) than the axial thickness profile generated from the anterior and posterior surfaces of a hydrated lens. Also, the radial position may be approximately 1.4 times smaller for non-hydrated lenses.

[0237] Referring now to FIG. 6, there is shown a graphical representation 600 of the front 603 and back 604 curves of the optical zone of a hydrated ophthalmic lens.

[0238] The graphical representation 600 includes a first axis having a scale of hydrated surface position 601 and a second scale having a scale of hydrated radial position 602. The first curve maps values ​​of an anterior curve 603 and the second curve maps values ​​of a posterior curve 604 of the ophthalmic lens optical zone.

[0239] 7, there is shown a graphical representation 700 of the optic zone axial thickness profile 703 of a non-hydrated ophthalmic lens. In a preferred embodiment, the axial thickness profile can be adequately described by an even fourth-order polynomial. Coefficients from this model can be referenced to generate the optic zone portion of a grayscale print pattern, or other energy transmittance or energy intensity map pattern.

[0240] The graphical representation 700 includes a first axis having a scale of unhydrated axial thickness 701 and a second scale having unhydrated radial position 702. A curve maps values ​​of axial thickness 703 of the ophthalmic lens optical zone, the numerical values ​​correlating with thickness 704 displayed in the center of the graphical representation 700.

[0241] For astigmatic lenses, the optical power varies with the direction (meridian) of the optical zone. For example, -2.75D / -4.5DX90 has a power of -2.75D vertically and -7.5D horizontally. The resulting axial thickness profile may vary meridian-wise within the optical zone, being "flattest" vertically and "steepest" horizontally.

[0242] 8, a false-color image of a thickness profile 800 is shown for an optical zone, with a first intensity 801 representing a small thickness and a fourth intensity 804 representing a region having a relatively large thickness. One or more intermediate thicknesses 802-803, such as a first intermediate thickness 802 and a second intermediate thickness 803, may also be included. Each thickness may be achieved by depositing an appropriate amount of polymerizable mixture at the respective location indicated by the thickness profile 800, allowing the polymerizable mixture to settle, pinning the settled polymerizable mixture in place via a gelation process, and finally curing the deposited and pinned polymerizable mixture.

[0243] The horizontal (most negative power) and vertical (most positive power) axial thickness profiles may be modeled as fourth-order polynomials, and the coefficients may be used to generate the optical zone grayscale print pattern represented by thickness profile 800.

[0244] Energy-transmitting print pattern generation In some embodiments, the energy-transmissive 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 (exemplarily defined by an axial thickness profile), and a periphery 805. Other regions, such as regions containing drugs or other leachable substances, may also be included. Each region may be defined in various ways. For example, as a non-limiting example, the pixel size of the print pattern may be specified to be approximately 0.021 mm. The unhydrated lens diameter may be, for example, 10.0 mm. The number of pixels in the X and Y directions is defined by the following relationship:

[0245]

number

[0246] This definition ensures that the center of the lens is at the center of the printed pattern. pixels Ensure that is odd.

[0247] Several grayscale levels may also be specified, for example an 8-bit (255 gray levels) print pattern. It is within the scope of the present invention that both of these values ​​may be varied, which may affect the quality of the printed lens.

[0248] spherical surface Spherical lenses are generally rotationally symmetric (within 10% of symmetry) and contain an optical zone that can be defined, for example, by using the unhydrated lens center thickness and coefficients from an even fourth-order model:

[0249]

number

[0250] where (x0, y x ) is the center of the printed pattern. Other variations are also within the scope of the present invention.

[0251] The center thickness (CT) used to generate the thickness profile may be based on the hydrated thickness relative to the number of layers to be printed times the layer thickness. Thus, if the hydrated lens CT is 0.120 mm, the number of layers to print 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.

[0252] In some preferred embodiments, this may be done to ensure that the ratio of the "lightest" to the "darkest" pixels in the pattern remains within an acceptable range for printing. In other embodiments, the image may be converted to a binary image by the printhead controller software. If the grayscale range is too large, the "light" areas may not have enough "dark" pixels to create a smooth lens surface.

[0253] The thickness can be calculated for pixels where r is less than the unhydrated optical zone radius (rmax), typically 4.0 mm / 1.4 (~2.857 mm).

[0254] The periphery 805 is the region where r (mm) is outside the optical zones 801-804 but within the lens diameter. Many different methods can be used to define the thickness profile of the periphery. For example, in some preferred embodiments, the pattern uses the thickness of the edge of the optical zone for all pixels in 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 "edge" of the lens, and using higher-order polynomials or conic sections to tape the thickness from a value at the optical edge to a value defined at the "edge" of the lens, adding "reinforcement" rings to the periphery to improve lens handling, tapering using different methods in different zones of the periphery, and combinations of tapering and "reinforcement" rings.

[0255] Toric (astigmatic) lenses The optical zone is not rotationally symmetric and may be defined using the unhydrated lens center thickness, two (2) sets of coefficients from an even fourth order model for the most positive and most negative power meridians, and the desired angle in the print pattern for the most positive power meridian.

[0256] For example, in some embodiments, a print pattern may be generated for calculating the "effective" second order coefficients for each principle meridian.

[0257]

number

[0258] The "equivalent" r2 coefficient is defined as the average of the two effective coefficients. The astigmatism coefficient is defined as:

[0259]

number

[0260] where C 2,effective,plus is the effective second coefficient of the most positive meridian, and C 2,effective,minus is the effective second coefficient of the most negative meridian. For each pixel in the lens print pattern, the distance (r(x,y)) from the lens center and the angle (θ(x,y)) in standard Cartesian coordinates are calculated.

[0261] The optical zone thickness may be defined as:

[0262]

number

[0263] where φ is the angle of the most positive meridian.

[0264] The thickness at the edge of the optical zone varies with angle. For toric print patterns, a transition zone can be created to produce a single thickness value for all angles. The transition zone may be a 0.5 mm wide annulus for hydrated lenses (0.5 mm / 1.4 for non-hydrated lenses). The target thickness for the transition may be equal to or essentially equal to the minimum thickness at the optical zone boundary.

[0265]

number

[0266] 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:

[0267]

number

[0268] The slope of each point is defined as follows:

[0269]

number

[0270] The intercept for each point is defined as follows:

[0271]

number

[0272] The thickness at each point in the transition region is:

[0273]

number

[0274] Referring now to Figure 9, an exemplary graphical 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 within 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, using only the edge of the transition zone and the minimum thickness for the edge of the optical zone thickness and the edge of the transition zone thickness, respectively. All pixels outside the lens diameter can be set to 0.

[0275] FIG. 10 illustrates a thickness profile of a peripheral region 1000 of an ophthalmic lens having multiple modified thicknesses 1002-1004 over the peripheral region of an optical zone 1001.

[0276] 11 illustrates a thickness profile of a complete ophthalmic lens 1100. The illustrated thickness profile includes lens portions 1101-1105, which include optic zones 1101-1104 and a peripheral region 1105. Each of the lens portions 1101-1105 includes one or more pixels 1106 (shown in an expanded view). Each pixel 1106 may be associated with a thickness.

[0277] Pattern printing In some embodiments of an energy transparency pattern (e.g., and energy intensity pattern or grayscale pattern) corresponding to a printed pattern, "light" pixels may represent unprinted areas and "dark" pixels 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.

[0278] In some exemplary embodiments, the print pattern "intensity" of the lens is:

[0279]

number

[0280] where floor() converts the value to the smallest integer.

[0281] All pixels outside the lens may be set to 255, with smaller intensity values ​​corresponding to greater thickness and the smallest value corresponding to the smallest thickness.

[0282] A value of 255 corresponds to an 8-bit image. If more than 255 gray levels are used, the value of 255 is replaced by the number of gray levels. For example, for a 10-bit image, the value is 1023.

[0283] Referring now to FIG. 12, method steps for forming an ophthalmic lens according to some embodiments of the present disclosure are presented in flowchart form.

[0284] In step 1202, the method includes positioning a substrate at a first position relative to an additive manufacturing print head. The substrate may include a receiving portion, which may be planar or arcuate. The receiving portion may serve as a receiving surface for a first pass of the print head to deposit the polymerizable mixture. After the first pass, the receiving surface typically includes at least some areas with previously deposited polymerizable mixture.

[0285] In step 1204, the method may include ejecting a first pattern of deposited droplets of polymerizable mixture from a print head, the pattern of deposited droplets of polymerizable mixture being formed corresponding to a first portion of an energy transmittance map of the ophthalmic lens. The pattern is preferably a two-dimensional image representing the light intensity through the desired optical system. Droplets ejected at a time designation, such as T1, may be relative to other time designations. In a preferred embodiment, the two-dimensional representation has numerical values ​​associated with X, Y positions (or other coordinate designations). The numerical values ​​represent the amount of light passing through the optical element at the positions designated by the X, Y axis designations. The printed pattern may be based on numerical values, and in some embodiments, the amount of polymerizable mixture deposited at locations on the receiving surface corresponding to the X, Y pattern correlates with the numerical values ​​(e.g., lighter areas have lower X, Y numerical values ​​and receive less polymerizable mixture, while darker areas have higher X, Y numerical values ​​and receive more polymerizable mixture).

[0286] The design of an optical element can be achieved by analyzing the actinic radiation trace pattern of how light passes through the optical element. In some embodiments, the X and Y values ​​can then be derived from a mathematical model of the desired three-dimensional shape of the optical element.

[0287] In step 1206, the method may include receiving the deposited droplets of the polymerizable mixture at a receiving surface, which may include one or more of a substrate, a concentration of the polymerizable mixture formed from previously ejected droplets of the polymerizable mixture, and an insert. The insert may include, for example, an optical insert, a passive electronic device, an active electronic device, and / or a power source such as a battery, a harvesting device, or an antenna.

[0288] In step 1208, droplets of the polymerizable mixture may be deposited on the receiving surface at a second time (T2) and exposed to a pinning process. The pinning process causes partial polymerization of the deposited droplets of the polymerizable mixture. Preferably, the partial polymerization results in a viscous cohesion of the partially polymerized mixture that is resistant to flow but can integrate with subsequently deposited polymerizable mixture.

[0289] In step 1210, the method may include repositioning the substrate (and deposited polymerizable mixture) to a next position (position +N) relative to the print head.

[0290] In step 1212, the method may include ejecting a next pattern of deposited droplets of the polymerizable mixture corresponding to a next portion of the energy transmittance map of the item being formed, such as an ophthalmic lens being formed.

[0291] In various implementations of the 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 dwell times that allow gravity and other natural forces, such as surface tension and microforces, to act on at least some of the deposited droplets of the polymerizable mixture to smooth the surface of the deposited polymerizable mixture, fill gaps between the deposited droplets, and cause the deposited material to coalesce with previously deposited and pinned material. Thus, in step 1214, a next pattern of droplets of polymerizable material may be ejected. The pattern may be the same pattern as the previous pattern or a different pattern.

[0292] In step 1218, the polymerizable material deposited in the current pass of the print head may be integrated with material on the receiving surface, such as previously deposited material. In some embodiments, the integrated material may form a single volume of polymerizable mixture on the substrate.

[0293] In step 1220, one or both of natural forces and gravity may act on at least some of the deposited droplets of polymerizable mixture to smooth the surface of the deposited polymerizable mixture, fill gaps between the deposited droplets and the deposited material, and cause the deposited material to coalesce with previously deposited and pinned material.

[0294] In step 1222, the method may include curing the deposited droplets of the polymerizable mixture.

[0295] In some embodiments, the pinning process can include exposing the deposited droplets of the polymerizable mixture to actinic radiation of a first wavelength for a limited time sufficient to cause gelation of the deposited droplets of the polymerizable mixture without causing hardening of the deposited droplets of the polymerizable mixture. Similarly, in some embodiments, the curing process can include exposing the deposited polymerizable mixture to actinic radiation of a second wavelength for a sufficient time and intensity to cause polymerization of the deposited droplets of the polymerizable mixture. Some embodiments can also include accelerating the curing process by increasing the ambient temperature.

[0296] 13 , a schematic diagram illustrates the deposition of one or more polymerizable mixtures 1302 from one or more print heads 1301 to form an ophthalmic lens 1307. The print heads 1301 deposit the polymerizable mixture 1302 until a volume of the polymerizable mixture 1303 is formed on receiving areas 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 some of the receiving areas 1306 of the substrate 1305 act as receiving surfaces for the deposited polymerizable mixture 1302 until the volume of the deposited polymerizable mixture 1303 covers the footprint area for the design of the ophthalmic lens 1307.

[0297] As described herein, in some preferred embodiments of optical elements, the amount of polymerizable mixture 1302 deposited from print head 1301 to form ophthalmic lens 1307 varies according to a two-dimensional pattern representing an integer map of energy intensity (which may represent the transmittance of energy through the ophthalmic lens).

[0298] The pattern is preferably a two-dimensional image representing the light intensity passing through the desired Ophthalmic Lens 1307. In a preferred embodiment, the two-dimensional representation has respective numerical values ​​associated with a plurality of X, Y locations. The numerical values ​​may represent the amount of light passing through the Ophthalmic Lens 1307 at a given location designated by the X, Y axis designation.

[0299] Control commands to the print head cause the print head 1301 to deposit the polymerizable mixture 1302 based on a two-dimensional print pattern that specifies the amount of polymerizable mixture 1302 to be deposited at a given X, Y location. After multiple successive depositions of the polymerizable mixture 1302, the volume of polymerizable mixture 1303 on the substrate 1305 has a three-dimensional shape that represents a mathematical model of the desired ophthalmic lens.

[0300] The two-dimensional printed pattern of the amount of polymerizable mixture, representing the amount of light passing through the ophthalmic lens 1307 at a given location designated by the X, Y axis designation, may also correlate to the amount of polymerizable mixture 1302 deposited at the location on the receiving surface 1304 (e.g., lighter areas of the two-dimensional printed pattern have lower X, Y numerical values ​​and receive less polymerizable mixture, and darker areas have higher X, Y numerical values ​​and receive more polymerizable mixture).

[0301] In some embodiments, the design of an ophthalmic lens may be achieved by analysis of the actinic radiation trace pattern of how light passes through the ophthalmic lens. Preferably, the X and Y values ​​may then be derived from a mathematical model of the three-dimensional shape of the desired ophthalmic lens.

[0302] According to the present invention, a two-dimensional printed pattern specifying the amount of polymerizable mixture to be deposited at a given X, Y location is printed multiple times in successive passes of the printhead over the substrate 1305. The deposited polymerizable mixture 1302 is received onto a receiving surface 1304. The receiving surface 1304 may include one or both of a previously deposited volume of polymerizable mixture 1303 and a receiving area 1306 of the substrate 1305.

[0303] 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 polymerizes sufficiently to prevent (or at least substantially slow) the movement of the polymerizable mixture received on the receiving surface, allowing the subsequently deposited polymerizable mixture 1302 to fuse with the previously deposited (and pinned) volume of polymerizable mixture 1303 and form a structure having a single mass of polymerizable mixture. In a preferred embodiment, fusing may include mixing or interspersing with the previously deposited and pinned volume of polymerizable mixture 1303 such that, once the volume of polymerizable mixture 1303 is cured, no individual layers or stripes of polymerizable mixture 1302 are discernible within the volume of polymerizable mixture 1303 formed on the receiving area 1306 of the substrate 1305. Such an embodiment may be preferred because unwanted diffraction may be an optical quality resulting from successive steps or other interlayer artifacts associated with disparate layers of polymeric material present in an ophthalmic lens.

[0304] Prior to pinning, spontaneous forces may be applied for a period of time to act on the surface 1304 of the volume of polymerizable mixture 1303 to smooth the surface 1304 and / or fill in any stromal abnormalities in the surface (compared to the surface of the machined lens and / or the lens formed from the machined mold part), thereby improving the optical quality of the resulting ophthalmic device. The spontaneous forces may include, for example, but are not limited to, one or more of VanderWaals forces (e.g., Keesom forces, Debye forces, and London dispersion forces), ionic dipole forces, ion-induced dipole forces, beta bonding, and dipole-dipole bonding forces (e.g., hydrogen bonding).

[0305] Curing of the volume of polymerizable mixture 1303 follows the deposition of droplets of polymerizable mixture 1302 in a final pass of print head 1301 and substrate 1305. Curing may be accomplished by exposing the volume of polymerizable mixture 1303 to actinic radiation and / or heat sufficient to cause substantially complete polymerization of the volume of polymerizable material 1303.

[0306] As shown, Figure 13 shows a print head 1301 that is essentially perpendicular to the apex 1308 of the deposited polymerizable mixture 1303. In various embodiments, the droplets of polymerizable mixture 1302 may (or may not) follow a trajectory that is 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 previously deposited polymerizable mixture 1303.

[0307] Referring now to FIG. 13A , the print head 1301 is shown moving in a print path direction 1309. The deposited droplets of the polymerizable mixture 1302A follow a drop trajectory 1309, which is influenced by the speed and direction of the print head 1301 as the droplets of the polymerizable mixture 1302A are ejected. The drop trajectory 1309 has its own speed and direction. In accordance with the present invention, in some embodiments, the print head 1301 and drop trajectory 1309 may be at an angle other than perpendicular to the vertex surface of the receiving surface 1304. At least a portion (e.g., possibly a majority) of the deposited droplets of the polymerizable mixture 1302A consolidate and / or fuse with the previously deposited polymerizable mixture 1303A. After consolidation, the deposited polymerizable mixture 1302A may be exposed to actinic radiation conditions, such as actinic radiation, sufficient to cause gelation and / or pinning, and may ultimately be cured. In this way, the present process differs from previously known processes that require small portions of additive manufacturing material to be placed on a surface in an incremental manner and not integrated into previously deposited material before being cured.

[0308] Referring now to FIG. 13B , a substrate 1305 is shown having a receiving area 1306 and polymerizable mixture deposited from a first deposition event 1311, a second deposition event 1312, and a third deposition event 1313. Each deposition event can include ejecting a pattern of polymerizable mixture from the print head 1301. The pattern of polymerizable mixture can be ejected during relative movement of the print head and substrate 1305 or while the print head 1301 is stationary relative to the substrate 1305. While polymerizable mixture from only three deposition events is shown, it should be noted that the present invention is not limited to the maximum number of deposition events that may be optimal for forming a desired object. For example, in some embodiments, 8, 12, 16, 20, or 24 deposition events may be optimal for forming an ophthalmic device. In other embodiments, 64 or more deposition events may be optimal for forming an optical device for use on or outside the eye. The movement of the print head 1301 relative to the substrate 1305 can include one or both of rotational and lateral movement.

[0309] After the deposition event, the deposited polymerizable mixture 1311-1313 may melt, and a gelling or pinning process may be induced by exposure to actinic radiation conditions. After the final deposition event, a curing process may be performed to harden the deposited polymerizable mixture 1311-1313.

[0310] Final curing of the deposited polymerizable mixture 1311-1313 forms an ophthalmic device 1314 or other product.

[0311] During successive deposition events of deposited polymerizable material 1311-131, successive receiving surfaces 1311a, 1312a, 1313a formed by each polymerizable material deposition event may be positioned such that each receiving surface 1311a, 1312a, 1313a serves as the receiving surface for the subsequent deposition event and the backcurve for the subsequent sub-optic formed by the subsequent polymerizable material deposition event. Each addition of polymerizable material may increase the sub-optic's backcurve diameter 1315, 1316, 1317 (compared to other backcurve parameters formed via the previous polymerizable material event).

[0312] Referring now to FIG. 14 , exemplary dynamic shapes of droplets of polymerizable mixture 1401 are shown at various times 1402 after being ejected from a printhead. According to the present invention, the shape of the droplets 1401 can change based on the velocity of the droplets 1401 traveling through the ambient atmosphere. In some preferred embodiments, articles formed by the processes disclosed herein are generally insensitive to the shape of the droplets of polymerizable material 1401. The relatively small mass of each droplet 1401 and the integration of the droplets into other polymerizable material on the receiving surface make the shape of the manufactured article essentially insensitive to the shape of the individual droplets 1401 or changes in the shape of the droplets 1401 at various times 1402 after being ejected by a printhead (not shown in FIG. 14 ).

[0313] Referring now to FIG. 15, a flowchart 1500 illustrates exemplary method steps that may be performed in some implementations of the present invention.

[0314] In step 1501, the process may include placing a substrate in a first position relative to an additive manufacturing print head.

[0315] In step 1502, the process may include ejecting a first pattern of deposited droplets of the polymerizable mixture from a print head, the first pattern of deposited droplets of the polymerizable mixture corresponding to a first portion of the grayscale image.

[0316] In step 1503, the process may include receiving the deposited droplet of the polymerizable mixture at a receiving surface, which may include one or more of a substrate, a previously ejected droplet of the polymerizable mixture, and an inserted article, which may include, by way of non-limiting example, one or more of an optical element, such as a rigid transmissive lens, an electronic device, and a power source.

[0317] In step 1504, the process may include repositioning the substrate to a next position relative to the print head. Repositioning may include moving one or both of the substrate and the print head relative to the other.

[0318] In step 1505, the process may include ejecting a next pattern of deposited droplets of the polymerizable mixture from the print head corresponding to a next portion of the grayscale image.

[0319] In step 1506, the process may include allowing a physical force, such as gravity, to act on the deposited droplets of the polymerizable mixture.

[0320] In step 1507, the process may include consolidating at least some of the droplets to form a composite volume polymerizable mixture on the substrate.

[0321] 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.

[0322] In step 1509, the process may include repeating the positioning and deposition steps for multiple passes of the print head relative to the substrate.

[0323] In step 1510, the process may include curing the polymerizable mixture of composite volumes to form an ophthalmic lens having multiple sub-optical elements along the same optical path.

[0324] The process can include, after each pass of the printhead over the substrate, integrating at least some of the droplets of the polymerizable mixture deposited during the current pass with a previously deposited polymerizable mixture on the receiving surface to form a composite volume of the polymerizable mixture on the substrate, whereby integration can form polymer chains such that monomers contained in the polymerizable mixture deposited in different depositions are contained in different volumes of the deposited polymerizable mixture.

[0325] In step 1511, the process may include releasing the formed ophthalmic lens from the substrate. Release may be achieved, for example, by immersing the formed ophthalmic lens and substrate in a hydration solution. The hydration may expand the ophthalmic lens and release it from the substrate.

[0326] Common findings Although the specification and claims sometimes refer to mixtures (such as polymerizable mixtures), initiators, and other additives, it is within the scope of the present invention that the materials and compositions defined herein may include one, two, or more individual components. In such embodiments, the total amount of each component should correspond to the amount defined above for the individual component.

[0327] The formula(s): mixture(s), initiator(s), etc. indicates that one, two, or more of the individual components may be present, whereas when formula 1 is used, only one (1) of each component is present.

[0328] Formula % should be understood to mean weight % of each component unless otherwise specified.

[0329] conclusion Several embodiments of the present invention are described. While the specification contains many specific implementation details, these should not be construed as limitations on the scope of any disclosure or what may be claimed, but rather as descriptions of features unique to particular embodiments of the present disclosure.

[0330] Certain features described herein in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Furthermore, although features may be described above as acting in a particular combination, one or more features from the described combination, even if initially described as such, may in some cases be omitted from the combination, and the described combination may be directed to a subcombination or a variation of the subcombination.

[0331] For example, although steps are depicted in the figures in a particular order, this should not be understood as requiring such steps to be performed in the particular order or sequential order shown, or that all of the steps depicted be performed, to achieve desirable results. In certain situations, multitasking and parallel processing may be advantageous.

[0332] Furthermore, the separation of various system components in the above embodiments should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems may generally be integrated together in a single software product or packaged into multiple software products.

[0333] Thus, specific embodiments of the subject matter have been described. Accordingly, other embodiments are within the scope of the following claims. The actions recited in the claims can be performed in a different order and still achieve desirable results. By way of example, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results. In certain situations, 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 invention.

Claims

1. 1. A method of forming an optical lens having a plurality of sub-optical elements, comprising: placing a substrate at a first position relative to an AM print head; ejecting a first volume of the polymerizable mixture from a printhead in a first pattern of deposited droplets; receiving the first volume of polymerizable mixture onto one or both of the substrates; exposing the first volume of the polymerizable mixture on the substrate to actinic radiation conditions; combining a plurality of monomers in the first volume of polymerizable mixture to form one or more polymer chains; ejecting a second volume of polymerizable mixture from the printhead; receiving the second volume of polymerizable mixture onto a receiving surface, the receiving surface including one or both of the substrate and the first volume of polymerizable mixture; combining a portion of the first volume of polymerizable mixture with a portion of the second volume of polymerizable mixture to form a composite volume of polymerizable mixture; exposing the composite polymerizable mixture to actinic radiation conditions; combining a plurality of monomers included in the polymerizable mixture of the composite volume, thereby causing partial polymerization of the polymerizable mixture of the composite volume; forming a first sub-optical element through the partial polymerization of the polymerizable mixture of the composite volume; and curing the polymerizable mixture of said composite body.

2. 2. The method of claim 1, further comprising repeating steps a. through j. to form the plurality of sub-optical elements.

3. 10. The method of claim 1, wherein the pinning process comprises forming polymer chains comprising a first amount of monomer contained in the first volume of polymerizable mixture and a second amount of monomer contained in the second volume of polymerizable mixture.

4. 3. The method of claim 2, wherein a first pattern of deposited droplets of polymerizable mixture comprising at least one of the first volume of polymerizable mixture and the second volume of polymerizable mixture corresponds to an energy transfer map, the energy transfer map representing how an energy spectrum passes through the sub-optical element.

5. 5. The method of claim 4, further comprising containing the substrate and the first volume of polymerizable mixture and the second volume of polymerizable mixture in a controlled atmosphere having an oxygen concentration of up to 2.0% by volume.

6. 5. The method of claim 4, including providing an oxygen equilibrium concentration of the polymerizable mixture of said composite volume up to 8.0% by volume.

7. The method of claim 6 further comprising the step of equilibrating the oxygen concentration in the substrate with the oxygen concentration in a controlled atmosphere.

8. The method of claim 4 , further comprising repositioning the substrate to a second position relative to the additive manufacturing print head.

9. The method of claim 8 , wherein repositioning the substrate to a next position relative to the print head comprises changing the relative rotational position between the print head and the substrate.

10. The method of claim 9 , wherein repositioning the substrate to a next position relative to the print head comprises changing a relative lateral position between the print head and the substrate.

11. 5. The method of claim 4, wherein receiving the first volume of polymerizable mixture onto the substrate as the first pattern of deposited droplets comprises receiving a deposited amount of polymerizable mixture at a given location on the receiving surface that corresponds to a digital value associated with a pixel included in a grayscale image.

12. 5. The method of claim 4, wherein bonding a plurality of monomers contained in the polymerizable mixture of the composite volume, thereby causing partial polymerization of the polymerizable mixture of the composite volume, comprises a pinning process including exposing the first volume of polymerizable mixture to energy radiation of the first wavelength for a limited time sufficient to cause gelation of the first volume of polymerizable mixture, without causing complete curing of the first volume of polymerizable mixture.

13. 10. The method of claim 1, wherein curing the polymerizable mixture of the composite volume comprises exposing the polymerizable mixture of the composite volume on the substrate to energy radiation of a second wavelength for a sufficient time and for a sufficient intensity to cause polymerization of the polymerizable mixture of the composite volume.

14. 10. The method of claim 1, further comprising the step of allowing naturally occurring forces to smooth the surface of the polymerizable mixture of the composite volume.

15. 15. The method of claim 14, wherein the naturally occurring forces that lubricate the surface of the polymerizable mixture of the composite volume include van der Waals forces.

16. 15. The method of claim 14, wherein the naturally occurring forces that lubricate the surface of the composite volume polymerizable mixture include surface tension.

17. 13. The method of claim 12, further comprising the steps of curing the composite volume polymerizable mixture, releasing the composite volume polymerizable mixture from the substrate, and hydrating the cured composite volume polymerizable mixture.

18. 18. The method of claim 17, further comprising repeating steps a. through g. 10 to 20 times.

19. The method of claim 1 , wherein the first pattern of deposited droplets includes fiducial markings.

20. The method of claim 19 , wherein the fiducial marking comprises a divot.

Images