GLASSES LENS PRODUCTION BY MULTI-LAYER ADDITIVE TECHNIQUES

专利摘要:
The present invention relates to an additive processing method that is used to produce a customized spectacle lens by selectively constructing layers of radiation polymerized material on a lens substrate which has optical power properties noticeably different from the optical properties of the custom spectacle lens. the method involves obtaining the lens substrate, calculating the modifications necessary to convert the lens substrate properties into the desired set of custom lens properties, generating an additive layer design to achieve the calculated modifications, and identifying at least one control point for confirmation or revision of the additive layer design. the method further involves applying the liquid layers of radiation polymerizable material to the lens substrate and irradiating the liquid layers in selected areas with controlled radiation so that the material is only polymerized and the additive layer is only formed in the selected irradiated areas, according to the additive layer design.
公开号:BR112016022180B1
申请号:R112016022180-0
申请日:2015-03-26
公开日:2021-06-22
发明作者:Andrew J. Mckenzie；David Mark Ambler；Daniel Crespo Vazquez；Jose Alonso Fernandez；Juan Antonio Quiroga
申请人:Indizen Optical Technologies, S.L.；
IPC主号:

专利说明:

BACKGROUND OF THE INVENTION field of invention
[001] The field of the invention relates, in general, to methods of producing spectacle lenses, in particular, prescription eyeglass lenses and lens blank blocks using additive techniques rather than removing excess material . Description of Related Art
[002] Prescription spectacle lenses are commonly used to correct human vision errors, abnormalities, and focus deficiencies caused by genetics, age, disease, or other factors. In addition to correcting psychological vision problems, eyeglass lenses can be used as a fashion accessory or to protect the eyes from scratches or discomfort.
[003] Prescription eyeglass lenses must be tailored to meet the specific vision requirements of each individual. Various techniques have been developed over the years to achieve this goal. A common technique involves storing or retrieving semi-finished lens blank blocks that form a series of starting blocks with distinct surface curvatures so that only one side of the blank lens needs to be further shaped to achieve a given prescription. Therefore, the coated lens needs to be polished to an optical finish and beveled to the individually selected eyeglass frame shape. This can be a time-consuming process. Another technique involves storing or obtaining finished lenses that will just be beveled to the individual's selected eyeglass frame. However, finished lenses typically only approach prescriptions in 0.25D increments of cylinder and sphere corrections and therefore may be less accurate for correction. In addition, many more storage units are needed to cover the wide range of prescriptions an ophthalmologist will encounter. More recently, another digitally shallow lens technique using computer-controlled machining has gained prominence. The digital surface often requires only a limited number of semi-finished blank lens blocks or other starting lens constructions, but computer-controlled surface equipment allows for individualized or more complex prescriptions (eg, multifocal) are prepared. This method can involve significant expenditure on equipment and trained staff.
[004] Each of these techniques can be described as subtractive production methods, in which excess lens material is removed to create the desired lens or prescription properties. In such processes, there is often a significant amount of wasted material that must be safely handled, stored and disposed of.
[005] It will be desirable, then, if a controlled additive process can be developed for spectacle lens preparation.
[006]While additive type processes for spectral filtering are well known in the field of thin film deposition, these techniques are not used to create optical power changes for the final lens. Instead, they focus on maintaining any lens properties of an original optical part while changing specific spectral characteristics.
[007] Some other early developments of additive type techniques have been described in the art, but still require the use of at least one additional molding surface. For example, US Patents 4873029, 5178800 and 7002744 B2 each describe methods of producing various optical parts by positioning pre-existing shapes or lenses relative to a molding surface to create a lens-forming cavity, by placing the liquid lens-forming material in the cavity and solidifying the lens-forming material into the pre-existing lens or shape so that it combines to form a new optical part when the molding surface is removed. However, these techniques still require at least one precision molding surface for fabrication and require that the molding surface must be prepared, properly stored and maintained to achieve acceptable and consistent optical quality production.
[008]Other additive techniques based on sterolitography, melt deposition, jet printer or 3D printing advances are also of interest. Many of these require a support on which a desired three-dimensional part is built. These holders are often flat platforms, which are not intrinsically suitable for prescription eyeglass lenses. Furthermore, most supports are carefully removed or separated from the final printed object, which acts only as a base on which to build the desired object. Some developments have taken place to produce flexible contact lenses using these types of techniques. For example, U.S. Patent Nos. 7905594 B2, 8240849 B2 and 8318055 B2 and EP 2265430 B1 describe the use of a precision mold or forming optics as the removable platform on which to build the contact lens. The irradiation energy that causes the polymerization of the reactive solution to be directed through forming optics or precision mold to build the part against the surface. The contact lens or ophthalmic portion is then removed from the forming optic or mold to provide, by replication, an optical surface finish and desired lens curvature to the contact side of the created portion. U.S. Patent No. 7235195 B2 describes contact lenses produced by stereolithography on top of a liquid bath, specifically, without the use of any mold or support. All features of the desired lens are created by spatially controlled polymerization of the liquid bath surface through exposure to radiation, preferably from two beams at different angles.
[009] However, some disadvantages of additive production make it difficult to implement these techniques for spectacle lenses. Precise placement and control of layers is costly and time-consuming. Eyeglass lenses require much more material than contact lenses or eye implants and therefore exacerbate these disadvantages. Materials suitable for the production of additive plastic parts or even materials suitable for flexible, thin and small contact lenses cannot match the necessary structural and optical properties required for spectacle lenses that will be mounted on spectacle frames. Nevertheless, efforts for improvements and new inventions in the field of additive production techniques are warranted given the potential advantages of these methods. BRIEF SUMMARY OF THE INVENTION
[010]The inventors have determined innovative and effective approaches to create eyeglass lenses using additive production techniques. An existing optical lens substrate is used as a starting structure into which specific ophthalmic features are embedded using additive production techniques. Unlike other approaches to additive manufacturing, the lens substrate becomes an integral part of the final spectacle lens and the additive production processes of the invention are used to alter its physical and optical characteristics to create a custom spectacle lens for the needs of the specific user.
[011] Preferably, the lens substrate is selected from finished lens blank blocks, semi-finished lens blank blocks, flat lens blank blocks, flat bevel lenses and finished bevel lenses. The lens substrate comprises at least a first and a second surface, one of which will be positioned closer to the eye and one which will be positioned away from the eye when used. In a preferred embodiment, the surfaces of the lens substrate can comprise treatments or coatings to improve adhesion of subsequent layers. In a preferred embodiment, the lens substrate will have optical power properties that are noticeably different, when viewed with the naked eye, from the optical power properties of the custom spectacle lens.
[012]The process includes calculating the modifications necessary to convert the optical power properties of the lens substrate to the desired properties for the custom spectacle lens and then generating an additive layer design to achieve these modifications. In another embodiment of the invention, in addition to modifying the optical power properties, the additive layer design is calculated and generated to modify other lens substrate properties for the custom spectacle lens, such as polarization, photochromicity, UV transmittance, visible transmittance, light reflectance, hydrophobicity, chemical resistance, abrasion resistance, impact resistance and electrical conductivity.
[013] To create the additive layer design layers, the first radiation polymerizable material is applied as a liquid layer over at least a portion of one of the substrate surfaces and then a selected area of the liquid layer is irradiated with radiation that is controlled for the wavelength range, spatial distribution and energy to form an additive layer through polymerization only in the selected area of irradiation. The liquid layer is selectively irradiated and polymerized to form the additive layer according to the additive layer design. Furthermore, the additive layer is integrally bonded to the lens substrate.
[014] In a preferred embodiment, the radiation polymerizable liquid material is applied to only one surface of the substrate. In another preferred embodiment, the radiation polymerizable liquid material is applied to both the first and second surfaces of the substrate, simultaneously or sequentially. In preferred embodiments, the radiation polymerizable material is applied by methods such as spin coating, dip coating, spray coating, roller coating, blade coating or curtain coating.
[015] In a preferred embodiment, the angle and position of the lens substrate relative to the radiation polymerizable material can be controlled while the liquid layer is applied. In a preferred embodiment, the lens substrate is moving relative to the radiation polymerizable material as the material is applied. In a further preferred embodiment, the lens substrate moves in at least one direction chosen from the Y translation, the Z translation and the angle rotation A while the radiation polymerizable material is applied. In another preferred embodiment, the lens substrate is moving at an angle not perpendicular to the radiation polymerizable material being applied. In another preferred embodiment, the angle, speed and/or direction of movement of the lens substrate varies while the radiation polymerizable material is applied.
[016] In an additionally preferred embodiment, the lens substrate is moving at a non-perpendicular angle to the radiation polymerizable material during irradiation of the liquid layer. In a preferred embodiment, the lens substrate moves in at least one direction chosen from Y translation, Z translation and angle A rotation while the radiation polymerizable material is being irradiated. In another preferred embodiment, the angle, speed and/or direction of movement of the lens substrate varies while the radiation polymerizable material of the applied liquid layer is being irradiated.
[017] In a preferred embodiment, the radiation used to radiate the liquid layer is chosen from thermal energy, microwaves, radio frequency, ultraviolet, visible energy and infrared energy.
[018] Additional liquid layers of radiation polymerizable material can be applied to further build the features of the custom spectacle lens. In a preferred embodiment, the second layer of liquid is applied to an application zone selected from at least a portion of the first additive layer, at least a portion of one of the surfaces of the lens substrate, or a combination of both. a portion of a lens substrate surface or a portion of the first additive layer. In a preferred embodiment, this process is repeated for multiple additional liquid layers that can be applied to selected application zones from at least a portion of one of the surfaces of the lens substrate and/or portions of previously applied additive layers.
[019] In a preferred embodiment, the lens substrate is moving while additional liquid layers are being applied and this movement may not equal the substrate movement while the first liquid layer was applied. In a preferred embodiment, the angle, speed and/or direction of movement of the lens substrate varies as the radiation polymerizable material of the additional liquid layer(s) is applied.
[020] To form the additional additive layers, selected areas of each of the additional liquid layers are irradiated with radiation that is controlled for the wavelength range, spatial distribution and energy. This selective irradiation forms each additive layer by polymerizing only the selected area of each layer of liquid that is irradiated. The additional liquid layers are irradiated according to the additive layer design and the additional additive layers are integrally bonded to their application zones.
[021] In a further preferred embodiment, the lens substrate is moving while the additional liquid layer(s) are being irradiated and this movement may not equal the movement of the substrate as the first liquid layer was irradiated. In another preferred embodiment, the angle, speed and/or direction of movement of the lens substrate varies while the radiation polymerizable material of the additional liquid layer(s) is irradiated.
[022] In a preferred embodiment, the additive layer design includes two or more additive layers. In another preferred embodiment, the additive layer design includes at least 50 additive layers. In another preferred embodiment, the additive layer design includes at least 200 additive layers.
[023] In another preferred embodiment, the method additionally comprises at least one control point with error limits for the additive layer design. At a control point, an individual measures the localized physical and/or optical properties of the lens substrate and/or the additive layer or layers at one or more measurement locations, calculates the error between the measured properties and the expected results for the desired custom glasses lens additive layer design, compare the error with the error limits for the control point and if the error is greater than the error limits, review the additive layer design based on the difference between the measured result and the project. In a preferred embodiment, the localized properties are measured at the control point measurement location(s) and are selected from the slope, optical power, position and/or thickness (height) of the layer(s) (s) additive(s) present at the measurement location and the optical through power of the lens substrate combustion and the additive layers present at the measurement location.
[024]Some preferred techniques for measuring localized properties include reflected light deflectometry, transmitted light deflectometry, Moiré pattern comparison and triangulation.
[025] In a preferred embodiment, the additive layer or layers formed from the radiation polymerizable material(s) has(have) physical or optical properties measurably different from the lens substrate. In a preferred embodiment, the measurably different properties of the additive layer are selected from the refractive index, Abbe value, abrasion resistance, impact resistance, resistance to organic solvents, resistance to bases, Tg, visible transmittance, transmittance of UV, polarization or photochromic properties.
[026] In preferred embodiments of the invention, the radiation polymerizable material further comprises components to customize the physical, chemical, mechanical or optical properties of the lens for spectacles. In a preferred modality, the components are selected from photoinitiators, UV absorbers, UV reflectors, infrared reflectors, infrared absorbers, visible tints, dyes, pigments, photochromic agents, electrochromic agents, thermochromic agents, thermal stabilizers, electrically conductive materials, liquid crystal materials and polarizers, including active polarizing materials. In another preferred embodiment, the components can include decorations, particles with properties that improve or modify the optical or physical properties of the radiation polymerizable material, such as light-reflecting or light-absorbing particles, embedded sensors, transmitters or viewers.
[027] In preferred embodiments, the radiation polymerizable material of the additional additive layer(s) may be the same as or different from the radiation polymerizable material used for the first additive layer. In preferred embodiments, the radiation polymerizable material of the additional additive layer(s) comprises components different from the radiation polymerizable material used for the first additive layer. In another preferred embodiment, the additional additive layer(s) has physical or optical properties measurably different from the first radiation polymerizable material.
[028] In another preferred embodiment, irradiation of the selected area of at least one layer of liquid forms the resulting additive layer in a position so that it smoothes in relation to features such as discontinuities, defects or irregularities in a lens substrate surface or edges of one or more previously applied additive layers. In another preferred embodiment, a layer comprising a photoinitiator is applied as part of the method to produce the customized spectacle lens. BRIEF DESCRIPTION OF THE DRAWINGS
[029] Figure 1A and Figure 1B show an exemplary flowchart of the steps of an embodiment of the invention, in addition to the optional steps for alternative modalities.
[030] Figure 2 illustrates an example of a method of the invention to apply the radiation polymerizable material and to measure the optical properties of the applied layer(s) and/or the lens substrate. DETAILED DESCRIPTION OF THE INVENTION
[031] The present invention is incorporated into additive methods to produce an eyeglass lens by selectively adding radiation polymerizable layers to an existing lens substrate. In this way, the invention allows individually customized spectacle lenses to be created with the desired physical and optical properties by constructing standard lens substrates. No additional and costly replica forming optics or precision molding is required for the invention.
[032] Eyeglass lenses are ophthalmic lenses worn in front of the eyes. They can be over-the-counter, prescription or plan lenses. Depending on the individual's needs and desires, they can serve one or more purposes, which include correcting vision, providing enhanced eye protection or comfort, or being a current accessory. Eyeglass lenses are commonly mounted on frames designed to hold the lens in front of the wearer's eyes. Such structures include eyeglass frames (goggles), goggles, helmets, shields, visors, lens holders and other mounting devices.
[033] The present invention addresses the need to customize a lens for a specific person. This may provide the individual's corrective vision prescription and/or include other eyeglass lens attributes that the person has required. Some examples of other attributes of individuals may have a need to include functional or pattern paints, photochromic response to sunlight, or increased impact or abrasion resistance. In addition, the custom lens optical design can be selected or optimized for the individual's specific frame configuration, specific tasks the user will perform, or the way the individual moves their eyes or head to accomplish desired tasks. For example, if a very narrow frame has been chosen, but the individual frame has both distance and near vision correction requirements, the custom spectacle lens must accommodate both vision needs within a very large space. limited. As another example, if the custom spectacle lens is intended for primary use while viewing a handheld device, the transmittance of the lens and its ratio of distance versus proximity prescription areas may be slightly different than a custom lens for observing. distance while navigating. The present invention provides practical and effective methods of customizing these and other lenses by combining known ophthalmic lens fabrication with custom 3D additive production techniques.
[034] The additive process of the invention comprises at least one change in the optical power properties of the lens substrate to that desired for the custom spectacle lens. The additive process may also comprise other physical, chemical and optical changes between the lens substrate and the custom spectacle lens.
[035]As an aid to understanding, Figure 1A and Figure 1B provide an exemplary flowchart of steps of the invention, which includes several optional steps. Optional steps and any associated continuation actions are indicated in the flowchart by dotted lines. Details of the flowchart steps are further explained below.
[036] In step 100, a lens substrate is obtained for use in the invention. Many lens substrates are available on the open market from eyeglass lens manufacturers. It will be understood by the person skilled in the art that lens substrates can also be obtained by producing the substrates by various own methods or by outsourcing manufacturing. Lens substrates can be manufactured by many different methods, which include thermoset processes, thermoplastic injection or injection compression molding, reactive injection molding, controlled dematerialization techniques to shape or polish a starting part, additive techniques for building a substrate and other methods.
[037] Lens substrates are designed to have at least some of the essential properties required for spectacle lenses, but may not be fully configured with all attributes required by the individual or may not be of the final desired lens contour for mounting. Lens substrates can be flat, spherically curved, or can be complex or simple aspherical curvature. Their surfaces may contain discontinuities such as multifocal stepped sections or variant curvatures such as lenticular or progressive features.
[038]Examples of typical lens substrates include lens blanks that are produced from materials and designs suitable for ophthalmic lenses, but are not in final form for a user's use. The lens blanks need to be further shaped or modified to produce over-the-counter or prescription optical power or to fit within an eyeglass frame. Many spectacle lens blank blocks have a surface that is suitably curved or formed for mounting on spectacle frames and providing some ophthalmic attributes, but the other opposite surface needs to be ground and polished to complete the required full prescription power. by the user. Such spectacle lens blank blocks are known in the art as "semi-finished" lens blank blocks. "Finished" lens blank blocks have both surfaces primed to provide cylindrical and specific vision corrective optical power, but these blank blocks have larger diameters than most eyeglass frames so they can be custom beveled to the final size and shape needed to fit an individual's chosen frame. Other lens substrates suitable for the invention include flat lens blank blocks, which do not have vision corrective power, but may include other spectacle attributes such as ink, polarization, photochromic response, impact resistance or other individual desired features. Other lens substrates suitable for the invention include beveled lenses or lens blank blocks that have been shaped to fit the final selected spectacle frame. Such beveled lenses may have corrective vision optical power or no power (flat).
[039] Preferably, the obtained lens substrate will have at least some attributes desired by the individual for their custom spectacle lens. This can be as basic as being a plastic or glass material that will not unacceptably deform in the frame or degrade very quickly in use. The lens substrate can also provide some of the desired vision correction (eg distance correction, but without actually adding power). As other examples, semi-finished lens blank blocks can provide initial curvature(s) to prepare vision correction or a suitable lens curvature for frame setup. The lens substrate may also include additional desired features such as, for example, polarization, coloration, gradient coloration, photochromic properties, blocking of ultraviolet (UV) or infrared light, light-absorbing particles, or electrochromic properties. The lens substrate may also comprise active display elements, sensors, transmitters, decorations, optical microelements, or other features. The lens substrate can provide some physical properties, such as fundamental impact strength, abrasion resistance, thermal stability, desired refractive index, or other attributes. The lens substrate may also comprise other elements such as films, wafers, inserts or other objects.
[040] However, in all instances, the lens substrate does not incorporate all the attributes desired for the custom spectacle lens. The additive production techniques of the invention are used to provide additional custom attributes to the lens. This approach is both desirable and useful due to the fact that it means that a much more limited stock of substrates can be stocked. In addition, this smaller stock can comprise simpler and less expensive lens substrates, and the invention will be used to provide the more complicated, unique or expensive attributes desired on an individual basis.
[041] Preferred lens substrates for the invention include finished lens blanks, semi-finished lens blanks, flat lens blanks, flat bevel lenses, and finished bevel lenses.
[042] The lens substrate comprises at least a first and a second surface, one of which will be positioned closer to the eye and the other will be positioned away from the eye when used in the eyeglass frame.
[043]The lens substrate may comprise coatings or treatments on its surfaces. For example, one or both of its surfaces can be provided with hard coatings for abrasion resistance and/or improved chemical resistance. Other possible coatings include, for example, conductive, polarized, photochromic, electrochromic, electroactive, hydrophobic, anti-reflective, UV or visible filters or dyes. Treatments may have been carried out on the substrates to provide, enhance or alter surface properties such as, for example, cleanability, adhesion to subsequent layers, crack resistance, chemical resistance, thermal stability or other attributes. Such treatments can be applied by many known techniques, including plasma, corona, solution, solvent, steam and surfactants, among others. In a preferred embodiment, the lens substrate surfaces may comprise treatments or coatings to improve adhesion of subsequent layers, including adhesion to additive production layers.
[044]Step 200 summarizes the initial calculation and designates activities to convert the lens substrate properties to those desired for the custom spectacle lens. First, the lens substrate modifications necessary to achieve the desired properties for the custom spectacle lens are calculated. These modifications are then converted into a design of layers to be added to the lens substrate. In this description, the calculated project will be called the additive layer project. In addition, one or more control points are identified for the additive layer design to allow confirmation or revision as needed to achieve the custom spectacle lens.
[045] Specifically, for the invention, it is expected that the lens substrate will not have the desired optical power properties for the custom spectacle lens. In one embodiment, the lens substrate will have noticeably different optical power properties than the custom spectacle lens. As a non-limiting example, the lens substrate can be a finished spherical single vision lens with an optical power of -2 diopters, while the custom lens requires a spherical distance optical power of -2 diopters and a readable area. of add power 10 mm below the optical center with an optical power of +1.5 diopters. In a preferred embodiment of the invention, optical power differences between the lens substrate and the custom spectacle lens will be discernible to the naked eye. For example, in the non-limiting example given above, it would be possible to see a noticeable difference when viewing a printed page through each of these samples.
[046] In a preferred embodiment of the invention, the additive layer design is generated to convert the optical power properties of the lens substrate into noticeably different optical power properties as desired for the custom spectacle lens. In a further preferred embodiment, this discernible change in optical power can convert the optical power of the lens substrate into the total optical power required for the final custom spectacle lens prescription. In another preferred embodiment, the additive layer design can convert the optical power properties of the lens substrate into noticeably different optical power properties for the custom lens that are not the final required prescription, but are intermediate to these values and therefore , further simplify lens lens processing for custom eyewear. Such a shift to intermediate optical power properties may, in particular, be preferable when the lens substrate is a semi-finished lens raw block. A conversion of optical power properties by additive layer design to intermediate values may also be desired for the custom spectacle lens if it is anticipated that other specialized coatings or treatments of the custom lens will be performed. Thus, it is anticipated that the additive layer design of the invention will provide a discernible change in the optical power of the lens substrate, but may provide all or a portion of the total prescription power for the final custom spectacle lens.
[047] In a further preferred embodiment, the additive layer design will not only convert the lens substrate optical power into a different optical power desired for the custom spectacle lens, but will also provide other custom properties for the custom lens. To provide additional customization, the additive layer design can be calculated and generated to include modification of optical, chemical and physical properties between the lens substrate and the custom spectacle lens. As non-limiting examples, additive layer design can modify properties for the final custom eyeglass lens such as polarization, photochromicity, UV transmittance, visible transmittance, light reflectance, hydrophobicity, chemical resistance, abrasion resistance, impact resistance or electrical conductivity.
[048] The custom eyeglass lens attributes that must be supplied by the additive layer design, plus the lens substrate characteristics from step 100, are entered into the design calculations in step 200. The lens substrate surfaces will be measured ( for example, by optical or physical metrology) or known, and can be expressed by one or more equations or described by a unique set of xyz coordinates. These equation(s) or coordinate values, along with the desired change in optical power and any other features that the additive layer design intends to address are then inserted into the calculation routines to optimize and define the total changes required to convert from the lens substrate surface(s) to the custom spectacle lens. These calculations can be performed by many known techniques, including ray tracing, wavefront propagation analysis, curvature calculation, combinations of these techniques, and other techniques known to those skilled in the art.
[049]As an example, the lens substrate surface (or surfaces) can be modeled mathematically as a sum of multiple, orthogonal Zernike polynomials, ordered according to the Wyant-Creath scheme; where the coefficients of this surface representation become the input to the prescribed lens calculations. Calculations are then performed using accurate ray tracing to incorporate this lens substrate information with the custom spectacle lens parameters, and determine the required added-layer design characteristics to meet the desired optical power requirements for the custom lens. As another example, the new surface that will be created for the custom spectacle lens (by the material added to the lens substrate by the additive layer design) can also be represented by a separate expansion of multiple Zernike polynomials. To achieve the desired optical power requirements of the custom lens, the design coefficients of this second Zernike polynomial expansion are found by minimizing a merit function that compares the real power map at any stage of computation with a theoretical power map. . Optimization can be performed using the BFGS optimization algorithm (Broyden-Fletcher-Goldfarb-Shanno). Other calculation and optimization approaches will be recognized by those skilled in the art.
[050] Once the total amount of change that must be made to the lens substrate to arrive at the desired custom lens attributes is calculated, it is converted into a series of layers to be applied by additive processing to the lens substrate surface(s) to achieve the change. The additive layer design will be calculated and generated to selectively add material only in those areas where it is necessary. This additive process represents a very different technique for creating a custom spectacle lens. Previous approaches would approximate the optical power required for a prescription design by simple spherical and toroidal coating techniques, but were typically limited by distinct tooling and, preferably, large increments between power changes. Techniques that are more sophisticated may employ multiple calculation and optimization steps, but then feed this information into computer-controlled surface equipment which again removes excess material from the lens substrate or lens blank block, which causes the waste in the removal process. In contrast, the inventors' technique approaches this problem differently, and innovatively adds material selectively to achieve the custom lens rather than removing material from a raw lens block or existing material block.
[051] To generate the additive layer design, the thickness of the additive layer, as well as its position on the lens substrate surface (or in previous additive layers) and its slope relative to the lens substrate or additive layer(s) previous va(s) is calculated and optimized for realistic production applications. For example, it may not be reasonable in production to have a layer thickness of 0.1 millimeters which should be controlled to the accuracy of 0.1 nanometer; instead, you can design multiple thinner layers to achieve the same result. Alternatively, you can recalculate the additive layer design so that applied layers 0.1 millimeter thick are controlled to 1 micrometer (0.001 millimeter) accuracy.
[052]Additive layer design calculation and generation may include factors such as: the total number of layers; whether layers will be added to one or both surfaces of the substrate; whether the same or different materials will be used for each layer; and the position, thickness (height) and slope of each layer, plus the minimum/maximum acceptable limits for each of these three layer parameters. These factors can be determined and optimized at multiple locations across the lens substrate surface(s) to provide a more precisely tailored lens. In an additionally preferred embodiment, additive layer design decisions can consider practical factors such as keeping the number of layers or the number of radiation polymerizable materials to be used manageable and efficient within the intended production environment and planning the probability of error or control limits on layers so that stacked errors do not compromise the performance of the final design. Those skilled in the art will recognize other design factors that can be incorporated.
[053] At this point in the additive layer design calculations, both the final desired surface for the custom spectacle lens, zF(x, y) and the initial substrate surface, zS(x, y), are known. Therefore, at each design location (x, y), it was necessary to accumulate material between zS(x, y) and zF(x, y) to achieve the custom lens. The total height of material to accumulate at each design location is 0.1z(x, y) = zF (x, y) - zS(x, y) .
[054] As an example of the inventive process, one can consider the option that this total height of material is accumulated using layers with the same maximum local thickness of hL. It is then necessary to compute the local thickness of material to be added in each layer at the various locations (x,y) on the lens substrate surface(s) so that the addition of the different layers produces the surface desired end of custom eyeglass lens. This local thickness of each layer can be computed as tL(x, y) = max(O, min(zF(x, y) - zL-1(x, y), hL)), where zL(x, y) ) = tL (x, y) + zL-l(x, y) is the sagittal height of the surface of the L-th layer of radiation-cured material to be added. The values for the lens substrate, zO(x, y), can be derived or obtained from direct measurement of the actual surface formed by the lens substrate and used for the initial calculations of tL(x, y) in the layer design additive. The values for the zL-1(x, y) layers used in computing tL(x, y) can be estimated based on the number of layers added as the additive layer design is calculated.
[055] In a preferred embodiment of the invention, the additive layer design comprises an additive layer. In another preferred embodiment, the additive layer design comprises two additive layers. In other preferred embodiments, the additive layer design comprises two or more additive layers, three or more additive layers, ten or more additive layers, fifty or more additive layers, or two hundred or more additive layers. For some custom spectacle lenses, five hundred or more additive layers can be used to create the desired lens properties.
[056]Step 200 design activities also incorporate one or more control points associated with the additive layer design. At a control point, the inventors interrogate the localized properties of one or more of the applied additive layer(s) in order to determine whether the additive layers are within expected tolerances or fits. or revisions need to be done in the additive layer project. These control points can comprise, for example, part of the computer instructions that manage the additive processing steps, or they can be separate actions taken to assist in the additive process. Measurements at the control point(s) may be conducted at one or more locations on the lens substrate, at one or more locations in the last applied additive layer, or at one or more locations in different additive layers. As an option for a control point, the same or different localized properties can be measured at different measurement locations.
[057]The measured results at the control point(s) will be compared with the expected additive layer design results at that point and the defined error limits for the control point(s). As described below, the comparison is used to determine whether revisions to the additive layer design, or to its application methods, are needed to achieve the desired custom lens. If the comparison indicates that corrections are needed, the measured results and error comparison are used to generate a revised additive layer design for further processing to achieve lens substrate to custom spectacle lens conversion results.
[058] Once the additive layer design and its control point(s) are generated, additive processing can be started at step 300. Optionally, before the first additive layer is applied, it can -if measuring or capturing the lens substrate, to confirm its surface properties, orientation, mounting or other characteristics, and ensure that the lens substrate is in the correct starting position for additive processing.
[059] Based on the additive layer design, a liquid layer comprising radiation polymerizable material is applied to at least a portion of a surface of the lens substrate. As will be described in more detail below, the liquid layer is the precursor to the additive layer. Liquid layers with a wide range of viscosities can be used, depending on the radiation polymerizable material and other components chosen. By selectively irradiating the liquid layer according to the additive layer design, an additive layer composed of radiation-cured material is formed on the lens substrate and/or on previous additive layers. Combining additive layers deposited according to the additive layer design with the lens substrate creates the custom spectacle lens.
[060] The liquid layer comprises radiation polymerizable material, which means that the material will form a solid polymeric system when subjected to radiation with a specific range of properties that include wavelength and energy density. For example, the material can be designed and formulated to be responsive to polymerization by ultraviolet radiation, but not infrared radiation. In another example, the radiation polymerizable material may be selectively responsive to polymerization when irradiated in shorter UV radiation, but not longer UV wavelengths (eg, 320 nm but not 365 nm). This allows for more control of the reaction process and less difficulty in handling. By controlling the wavelength range, energy density and spatial distribution of radiation, the desired effect of polymerization of the material can be achieved only in the irradiated area; by design, outside the radiated area, there is insufficient energy to make the material react. Energy density can also control the depth (thickness) of reaction and the time required for the material to polymerize.
[061] Several different radiation polymerizable materials are known in the additive processing art. Many are based on organic chemistry, but may include inorganic and metallo-organic species as well. A distinct advantage of the process of the invention is that the lens substrate can have certain physical and optical properties necessary for an ophthalmic spectacle lens that cannot be achieved simply with additive processing materials. For example, the lens substrate can provide all or most of the structural stability needed to maintain the integrity of the lens in the spectacle frame, while the additive layers add other features but are thin enough that this structural integrity is not degraded. . As another example, additive layers may have slight residual color or may lack UV blocking, which would make them unacceptable as a bulk lens material, but would not compromise performance in a thin layer added to the lens substrate. In this way, additive layers may not have the same restrictions on optical or physical properties as the lens substrate, but can be combined with the substrate to form a viable spectacle lens.
[062] In an embodiment of the invention, the radiation polymerizable material can create layers that have the same properties as the lens substrate. In that case, additive layers can be used to refine the optical or physical performance of the lens substrate. For example, additive layers can be added to create certain select areas of greater thickness or greater curvature, which correspond to the additional optical power in those regions of the final spectacle lens. In another example, the additive layer(s) can be positioned and designed to smooth out features, including discontinuities, defects or irregularities in the lens substrate.
[063] In another preferred embodiment, the radiation polymerizable material has optical or physical properties measurably different from the lens substrate, or upon polymerization, forms an additive layer with measurably different properties from the substrate of lens. For example, consider the aforementioned application of the individual who has both distance and distance vision correction requirements, but who selects a very narrow frame. The invention could use a lens substrate that meets the distance prescription, and additive layers of significantly higher refractive index, so that the additive layers provide proximity adding power with a thinner construction than a lens made with just an index of refraction. In addition, the additive layers can be specifically positioned to provide add-on power in the areas of the lens that will be needed in the small frame. As another example, for the aforementioned lens that is customized for distance viewing while sailing, the additive layer could provide polarization to block water glare, thereby ensuring better comfort and clarity of vision.
[064] In a preferred embodiment, the measurably different properties for the additive layer formed from the radiation polymerizable material are selected from refractive index, Abbe value, abrasion resistance, impact resistance, resistance to organic solvents, base resistance, Tg, visible transmittance, UV transmittance, polarization or photochromic properties.
[065] In addition to the radiation polymerizable material itself which has different properties compared to those of the lens substrate, the radiation polymerizable material can comprise components to customize the optical or physical properties of the spectacle lens. For example, components may comprise photoinitiators, UV absorbers, UV reflectors, infrared reflectors, infrared absorbers, visible tints, dyes, pigments, photochromic agents, thermochromic agents, electrochromic agents, polarizers, thermal stabilizers, electrically materials conductors, liquid crystal materials, active polarizing materials, light-absorbing particles, light-reflecting particles, and particles or materials that increase the impact strength or abrasion resistance of the radiation polymerizable material. In addition, components such as decorations, sensors, transmitters, displays and other small devices can be added to the radiation polymerizable material. One or more of these components can be combined in or with the radiation polymerizable material.
[066]The liquid layer is applied to an area of the lens substrate and/or area(s) of previous additive layers at least to the maximum extent of the area that its resulting additive layer is designed to cover. The liquid layer can be applied to one or both surfaces of the lens substrate. The liquid layer can be applied in a continuous layer over an entire surface or just a portion of a surface. For example, as mentioned in the illustration of the individual who has both distance and proximity vision correction requirements, but who selects a very narrow frame, the liquid layer could be applied only to the area of the lens surface used for vision viewing. of proximity, and the resulting additive layer would provide extra addition power in that region only. The layer can also be patterned or discontinuous. This could be useful, for example, if an active viewfinder or decorative design was being created on the custom eyeglass lens.
[067]The liquid layer can be applied by different methods known in the coating industry, selected for ease of application, production facility, versatility, cost, availability and other manufacturing considerations. For example, when the radiation polymerizable material is applied to only one surface of the lens substrate, single surface coating methods such as spin, spray, roll, blade and curtain coating can be used. If desired, the other surface of the lens substrate can be covered or shielded with a protective material to prevent the radiation polymerizable material from inadvertently coming into contact with it. For example, a thin sheet of protective plastic can be applied, statically held, or mechanically held against the other surface to protect it. As another example of protective materials, a lens substrate surface may comprise a protective coating or layer that may be removed after one or more layers of the additive layer design are applied.
[068] In many cases, the lens substrate may have a configuration such that one surface is concave and the other surface is convex. In theory, the liquid layer can be applied to each surface. The practical decision on which surface to use can be based on many factors and provided as an input value or further optimized during the design program. Examples of some of the factors to consider include capabilities and limitations of coating equipment, viscosity and uniformity of the radiation polymerizable liquid material, desired layer thickness, total layer thickness, and cosmetic, optical, and structural lens requirements for ultimate custom glasses.
[069] In another preferred embodiment, the radiation polymerizable liquid material is applied to both the first and second surfaces of the lens substrate. The layer can be applied simultaneously to both surfaces or sequentially to each surface.
[070] A preferred modality for simultaneous application of the liquid layer on both surfaces is dip coating. Dip coating equipment can also be used to apply radiation polymerizable material to only one surface of the lens substrate. In that case, the other surface is covered or protected so that additive processing is directed only to the unprotected surface of the substrate. For example, the other surface, or portions thereof, may be covered or protected by an applied plastic sheet, a release liner or film, or other protective materials known in the coating art.
[071] In a preferred embodiment, the angle and position of the lens substrate relative to the radiation polymerizable material is controlled while the liquid layer is applied. Such orientation control will assist in controlling the position and thickness of the resulting additive layer, in particular on a curved lens substrate surface.
[072]The lens substrate can be stationary during the application of the radiation polymerizable liquid material. However, in particular, if dip coating methods are used, it is preferred that the lens substrate move relative to the radiation polymerizable material as the material is applied. Such movement can be limited to one geometry axis or it can allow variation in multiple geometry axes. In addition, movement can include both translating and rotating the lens substrate with respect to one or more geometric axes.
[073]An example of a preferred method of lens substrate movement is illustrated in Figure 2. In this exemplary illustration, a lens movement configuration in combination with a dip coating system is shown. A typical method of immersing a part is to enter the part perpendicular to the liquid level. In contrast, it is preferred that the lens substrate 11 enters the bath of radiation polymerizable liquid material 21 and moves at a shallower angle for more control and more contact area between the lens surface and the liquid meniscus. As indicated, substrate 11 in this preferred embodiment can be moved with the following directional controls: lens rotation about the X axis (an angular movement, referred to for convenience as angle A, about the x axis that is perpendicular to the plane of the figure, that is, moving toward the viewer), movement in the Y direction (the horizontal direction in Figure 2), movement in the Z direction (the vertical direction in Figure 2), and simultaneous change of any combination of these factors . Furthermore, in a preferred embodiment, the rate of motion on any geometric axis or combination of geometric axes (including angle of contact with the liquid) can be changed or inverted during the time the layer is applied. These lens substrate movement angle, speed, and/or direction controls, plus the ability to vary these parameters while the radiation polymerizable material is applied, provide additional advantages for changing the thickness of the layer. additive applied, correct errors or accommodate previous features on the surface. An additional benefit of this method is that such controlled movement of the lens substrate can be used to smooth out defects or edges from previous additive layers or from the layer of liquid that is applied and irradiated.
[074] The support mechanism for lens substrate is not illustrated in Fig. 2, but various techniques are known to those elements of common knowledge in the art. For example, the lens substrate can be held or supported on its edges by a continuous holder, a distinct edge grip, or one or more stitch holders. Alternatively, if the radiation polymerizable material is being applied to only one surface (or only one surface at a time), the lens substrate can be supported on its other surface by vacuum, adhesive, or other physical mounting techniques. . As mentioned above, the other surface can also be covered with a protective material to maintain its original surface characteristics.
[075] Although the translational and rotational movement of the lens substrate is illustrated in Figure 2 in relation to a dip coating system, the control of the translational and/or rotational movement is also applicable to other methods of the invention. For example, the same type of lens substrate movements may be suitable for spray or curtain coating systems. In addition, other combinations of rotational/translating motion(s) may be suitable for various methods of applying the radiation polymerizable liquid material that will become the additive layers.
[076]Alternatively or in addition to the motion lens substrate, the radiation polymerizable material may be in motion while being applied. For example, when a liquid bath is used, the liquid can be mechanically stirred or subjected to ultrasonic energy or gas flows to cause movement in the volume of liquid material, or on the surface of liquid. Such movement may be preferred to reduce sharp or raised edges when the liquid is applied and cured.
[077] In a preferred embodiment, the environment around the lens substrate and the radiation polymerizable liquid material is controlled during liquid layer application. In a preferred embodiment, an inert or oxygen-free atmosphere (eg argon or nitrogen) is used in the vicinity of the coating equipment. As an example, the atmosphere can be controlled over the tank (such as a dip tank) or the exposed volume of liquid used during coating application. In another preferred embodiment, the relative humidity of the atmosphere is controlled to reduce unwanted water condensation, side reactions or haze of the radiation polymerizable material. In another preferred embodiment, the temperature in the vicinity of the coating equipment and/or the temperature of the radiation polymerizable liquid material are regulated to prevent or decrease changes in viscosity or control reaction rates. In another preferred embodiment, the atmosphere is controlled or filtered to reduce particulates or contaminants.
[078] In another preferred embodiment, the radiation polymerizable material can be kept in a containment tank or reservoir before and during the application of the liquid layer. The radiation polymerizable liquid material can be filtered to reduce unwanted particulate formation. In another preferred embodiment, the radiation polymerized liquid material is circulated or agitated to help maintain consistency, especially when additives or solid particles are present in the material. In another preferred embodiment, the radiation polymerizable liquid material is monitored and controlled with respect to chemical constituent concentrations, solids content, viscosity, color or other physical properties. In other preferred embodiments, the radiation polymerized liquid material and/or its container may be controlled with respect to temperature, humidity and exposure to atmosphere or other gases.
[079] Steps 320, 330 and 340 of Figure 1A describe optional actions that can be used in the invention. These steps act as an auxiliary control point. These steps are identified by the inventors, due to the fact that they can be of practical use in refining or further optimizing the control of additive layer properties. These optional steps may be particularly preferred when a large number of liquid layers will be applied or when a dip coating approach as described in Figure 2 is employed.
[080] In optional step 320, measurements are obtained to determine the position, thickness and/or inclination of the liquid layer in relation to the lens surface. This can be helpful in determining whether the material for the filler layer design is being applied correctly and whether the liquid layer is performing as expected. For example, you can expect the liquid to create a slight meniscus on the lens substrate. These optional measurements can check if the meniscus is occurring as expected or if the liquid's interactions with the surface are creating a different profile.
[081]Several different techniques can be used to obtain this information. Preferably, non-contact analysis techniques are used in order to preserve the quality of any previous additive layer(s), the substrate and the liquid layer and its polymerizable material by radiation that has not yet been polymerized. Preferably, the measurements comprise non-contact optical analysis, as these techniques often produce results that can be directly correlated to the expected optical properties of the final spectacle lens.
[082]Among the various measurement techniques, preferred techniques include transmitted or reflected light deflectometry, Moiré pattern comparison and triangulation.
[083]Preferred non-contact measurement techniques can provide information or direct data on one or more of the following layer parameters: layer position on the substrate, local slope and local height (thickness) of the layer. These values can be compared to the additive layer design from step 200 or can be used as inputs to calculate the optical power or other optical change (eg transmittance, polarization) achieved with the additive layer(s) previously applied or expected due to the applied liquid layer. In addition, some techniques can provide direct data about the optical power achieved by the layer or the optical power achieved by combining the layer with the lens substrate (and one or more prior additive layers, as applicable). Preferably, measurements are conducted at several different points. Alternatively, data can be taken along one line or multiple lines measured across the layer.
[084]The reflected light deflectometry is, in particular, suitable for specular surfaces. In many instances, both the lens substrate and the liquid layer will have suitably specular surfaces. For this technique, controlled light, and most preferably a collimated light beam or laser beam, is directed at the surface and the reflected beam analyzed for position and distortion to detect surface errors. Another possible technique is to sweep beam deflectometry, which sweeps or passes a controlled beam of light across a surface area for analysis at more positions. Shack-Hartmann wavefront sensor techniques can also be used, which measure the point displacement in the sensor plane of an image array. The localized slope can be calculated from the displacement and used to derive information about the layer and its expected optical power. Another form of deflectometry that can be useful for such measurements is reflected image screen tests, in which images reflected from distinct points are analyzed for distortion indicative of position and tilt errors. The image screen can be generated by active means (eg LEDs) or passive light screens such as a backlit screen. Extended structure deflectometry is another exemplary measurement technique, which uses active media (eg a computer screen image) or passive media (eg a projected dark/light pattern) to create an image for reflection and analysis. of errors.
[085] If diffuse surfaces are measured, triangulation is an example of a measurement technique that can be used in step 320. For a diffuse surface, a structured pattern is projected onto the liquid layer and/or surface of adjacent lens substrate, and offset detectors are used to triangulate the position and height (thickness) of the layer. One or more cameras positioned very close together or at a known offset from each other can be used as the detectors for triangulation.
[086] For transparent substrates, it can be measured with techniques for measuring reflected or transmitted light. In addition to the reflected light techniques described above, transmitted light deflectometry can also be used for optical through-power measurements. In this way, one can analyze how the additive layer in combination with the lens substrate or any previous layers changed the optical power of the lens substrate. An extended structured source is directed through the liquid layer and lens substrate, and distortion across the image is measured and related to position, thickness, and tilt errors. Moiré pattern comparison techniques can also be used, in which controlled grid pattern is imaged over a reconstruction grid after passing through the lens, and the error pattern observed. Another exemplary Moiré technique forms the image of a grid over another grid using the beam transmitted through the lens, in which distortions are correlated with lens errors.
[087] Another exemplary transmitted light measurement technique is light path triangulation. In an exemplary configuration of this method, a structured light source is directed through the liquid layer and lens substrate, and differences in the expected behavior of the grouping of transmitted light rays are observed. In another exemplary configuration, a calibrated camera is used to measure light reflected or transmitted through the lens. With such light path triangulation techniques, reflected and/or transmitted light measurements are used to calculate sets of surfaces and materials consistent with the observed input and output light ray groupings and the most suitable is determined.
[088]The measured results for the paths and light patterns are compared with the calculated results that would be expected for the project defined in step 200 of Figure 1A and in the particular layer to be applied. Consideration should be given to the difference in properties of the liquid layer versus a polymerized additive layer; they can have different indices, thicknesses and slopes, for example. Corrections or accommodations can be included in calculations for expected differences between the liquid layer and a polymerized layer. However, these techniques, in particular triangulation and deflectometry, can be useful in determining at least whether the liquid layer is applied in the expected position on the lens substrate surface (and/or in previous additive layers) and at a thickness enough.
[089]Step 330 describes a decision point at which the error (if any) measured in step 320 is compared with the error limits established by the user of this invention. If the measurements are within the error range, continue with step 400. If the error is greater than acceptable values, then proceed to step 340.
[090]If this optional sequence of steps is used and errors greater than expected are measured, step 340 provides calculation and application of corrective measures. Such corrective measures may include modifications to the additive layer design or its application methods. This may involve, for example, re-application or removal of the liquid layer over some or all of the previously applied area on the surface of the lens substrate. Alternatively, if changes in the liquid layer are less desirable, very problematic, or introduce impurities or other new errors, other ways to correct the errors can be employed. For example, calculations can be made to adjust the irradiation conditions that are subsequently applied to the radiation polymerizable liquid material. For example, if the liquid layer as measured is thicker than expected, more energy or more exposure time may be required to polymerize the entire thickness of material. In another embodiment, the position, height and/or slope conditions for one or more subsequent applied layer(s) can be recalculated and adjusted in step 340 and stored as a review for the design of additive layer, to correct the errors measured in step 320.
[091] In step 400, the liquid layer is irradiated to polymerize the material on the surface of the lens substrate. An important consideration for any additive layer material is that it must adhere well to the lens substrate and other layers (if used), and not degrade the optical performance of the lens. This is important to maintain the usefulness of the eyeglass lens and not shorten its lifespan. Delamination, peeling and cracking of coatings or layers on ophthalmic lenses have often been historical problems, especially when new technologies are introduced. The widely varying chemical, physical, and thermal stresses and exposures to which spectacle lenses are subjected (during initial component processing, spectacle assembly, and wearer use) can place severe and unexpected demands on the adhesion and integrity of a structure. of laminated lens. Therefore, the polymerized layer must be integrally bonded to the lens surface (and/or previously applied additive layers). Integrally bonded means that the polymerized layer is chemically bonded or strong and physically bonded to the anterior surface and/or the anterior additive layers so that the combined structure remains intact and without damage discernible to the naked eye either during normal lens processing or in its normal use as an eyeglass lens. Irradiation conditions are selected and managed to ensure that the inventive process achieves such an integral bond.
[092] The irradiation conditions in step 400 are selected with specific reference to the particular radiation polymerizable material used in the liquid layer and in relation to the position, slope and thickness of the liquid layer to be polymerized. For example, the radiation wavelength or wavelength range, radiation energy density and spatial distribution of the energy beam can all be controlled or selected to suit the physical and chemical properties of the particular radiation polymerizable material and of the applied liquid layer. A different energy density or spatial distribution of the energy beam can be used if the liquid layer is applied to both surfaces of the lens substrate instead of just one and the irradiation in step 400 is expected to selectively polymerize the material in both surfaces simultaneously. In another example, less energy or different irradiation conditions can be specifically chosen to selectively polymerize the material on only one surface of the lens substrate. Irradiation conditions can also be standardized to take into account absorption or reflection by the lens substrate; these substrate properties may be used to advantage to improve selective polymerization of an applied liquid layer or may require further adjustment of irradiation conditions to correct losses to (or through) the substrate.
[093] In addition, the way in which the liquid layer will be subjected to irradiation will be selectively controlled for the layer. This can include the exposure period and whether single or multiple irradiation periods are employed.
[094] Importantly for the invention, the irradiation conditions will be controlled to irradiate selected areas of the liquid layer. While this may cover all areas of the liquid layer, the invention specifically envisions only distinct liquid layer areas that are irradiated and selectively polymerized by that irradiation. Thus, as an example, a uniform liquid layer can be applied by curtain coating to the entire lens substrate surface, but irradiating with a sufficient wavelength range and energy density to form the polymerized additive layer it can only be applied to a selected area comprising 2mm dots in a 5mm space across the lens to form a dotted alignment pattern. As another non-limiting example, the uniform liquid layer described above can be irradiated by light with a wavelength range and energy density sufficient to form the polymerized additive layer, but only in a selected area to create an oblong section with 10mm wide and 20mm long on the bottom half of the lens substrate surface, for use as a reading zone on the lens for custom eyewear. The inventors intend that the radiation source be directed to the liquid layer with sufficient control of position and irradiation conditions in which the polymerization process is limited to selected directly irradiated areas. This is in contrast to previous methods which result in the general polymerization of the entire liquid layer or mass of radiation polymerizable material by transferring energy outside the radiated area. This is what is meant by selectively irradiating to produce a selectively formed polymerized additive layer.
[095]Irradiation energy can be concentrated in a narrow beam, collimated or presented in a more diffuse way. Depending on the selected source and polymerization requirements, different types of radiation sources can be selected, including monochromatic sources, lasers, actively or passively wavelength filtered sources, LEDs, blackbody sources, atomic emission lamps, fluorescent lamps and other sources known in the art. The frequency of irradiation energy can be in the UV, visible or infrared range or in other energy ranges that include microwaves, radio frequency, gamma radiation and X-ray radiation. Thermal energy can even be used if it is properly used. controlled for selective irradiation.
[096] In a preferred embodiment, the radiation used to radiate the liquid layer is chosen from microwave, radio frequency, ultraviolet energy or visible energy. In another preferred embodiment, a more limited wavelength range within the UV or visible energy spectrum is used to radiate the liquid layer. In a preferred embodiment, energy in the blue wavelength range of the visible spectrum is used for irradiation. In another preferred embodiment, UV energy in the range 350 to 380 nm is used to radiate the liquid layer.
[097] In another preferred embodiment, irradiation comprises using the blue channel energy (B) of a projector (R, G, B) (red-green-blue) as the controlled radiation to form the polymerized layer.
[098]Other light projections can also be used. These can include projectors with either UV light or visible light or a projector using different visible wavelength ranges or different color channels. Projector light sources can include laser diodes, multiple distinct sources in different wavelength ranges, filter wheels on single sources, and other techniques known in the art. Typically, three or more wavelength ranges are available on most projectors and one or more of these wavelength ranges can be used in the present invention.
[099] In another preferred embodiment, a digital light processing (DLP) projector that uses a UV light source can be used for irradiating a suitable radiation polymerizable liquid material. In another preferred modality, the DLP UV projector can be replaced by a laser hard-sweep beam, with the use of a UV laser source, and an oriented mirror with the use of piezoelectric actuators.
[0100] In a preferred embodiment of the invention, the irradiation source and/or the lens substrate can move relative to each other. In addition, the irradiation source can be directed to the same irradiation area one or more times during irradiation step 400. As an example, a selected area of the liquid layer can be irradiated to form the polyadditive layer. in that area. In this way, the edges of that area can be re-irradiated in combination with some surrounding area of the liquid layer, to smooth or lessen a bounce feature at the edge of the polymerized layer. As another example, multiple exposures can be used to allow the radiation polymerized reaction time to proceed, to ensure that sufficient energy is absorbed to complete the reaction or to reinforce the integral bond of the polymerized additive layer to the lens substrate and/ or to the previously applied additive layers.
[0101] The translational/rotational movements of the lens substrate proposed by the inventors and discussed above can be used during irradiation as well as during application of liquid layers. Such controlled movement of the lens substrate during irradiation can be used to smooth out defects or layer edges that are applied and irradiated or to ensure that irradiation occurs in those areas selected for the additive layer.
[0102]The liquid layer can be directly irradiated by the source in a continuous manner or the energy can be filtered, pulsed, cut, time-sequenced or reflected or transmitted through other control optics before reaching the layer.
[0103] In addition to forming the additive layers for optical power modification according to the additive layer design, step 400 selective irradiation can provide or enhance other lens properties for the custom spectacle lens. As non-limiting examples, selective irradiation can decrease yellowness, improve layer adhesion, improve layer durability through increased cross-linking or densification, or remove material from specific locations through evaporation or ablation. In addition, selective irradiation can be used to print visible or semi-visible marks on the custom spectacle lens.
[0104] In optional step 500, an individual may remove unreacted radiation polymerizable liquid material from the polymerized layer and/or lens substrate. One of ordinary skill in the art will recognize that this optional step may be included if it is useful for production operations, inspection of the polymerized layer, conservation of liquid radiation polymerizable material, and other engineering considerations. Unreacted material can be removed by moving the liquid-contacting lens substrate or moving the liquid material away from the lens substrate. For example, in Figure 2, the radiation polymerizable liquid material 21 is shown below the level of the lens substrate 11. In another exemplary embodiment of this optional step, unreacted material can be removed from the surface by chemical methods, such as solvent rinsing, solution soaking, steam cleaning, plasma treatment or other techniques known in the art. In another exemplary embodiment of this optional step, unreacted material can be removed by physical methods such as corrosion, washing, mild abrasive, scraper blade contact, absorption, or other techniques known in the art.
[0105]Step 600 identifies the possible location for a control point as identified for the design generated in step 200. At least one control point will be included in each embodiment of the inventive method. Control points can be placed after each layer to confirm the properties of the polymerized additive layer and the design performance as deposited at that point. Alternatively, control points may be placed less frequently than after each layer and may occur, for example, after a critical layer is applied or after a determined combined thickness of multiple polymerized additive layers. If a design control point has been placed at this point (after the layer is applied in step 300 and irradiated in step 400), then the process continues with step 700. If the design does not contain a control point after irradiation at step 400, then the process continues with step 900.
[0106]When step 600 identifies a control point, it continues with step 700, 800 and 820 (if necessary). In step 700, the polymerized additive layer (or a combination of additive layers) can be measured to determine the localized position of the layer(s), thickness (height), slope and/or optical power at relation to the surface of the lens substrate. As another preferred modality, optical through power or other transmitted light properties (eg, light transmittance, polarization, photochromicity, UV absorbance, etc.) can be measured in step 700 to determine how the com- Binding the lens substrate plus the polymerized additive layer(s) at a given measurement location altered the optical lens substrate properties. In a preferred embodiment, the measurement(s) of the lens substrate surface(s) is(are) used in combination with the measurements on the additive layers for reference and spot comparisons.
[0107]As outlined above for liquid layer measurement, several different techniques can be used to obtain this type of information or data. The techniques described in step 320 are exemplary of some of the techniques that are preferred and can also be selected for use in step 700. The same measurement technique can be used for both the liquid layer and the layer(s) ( s) polymerized additive(s) or different measurement techniques can be selected for each step. In another preferred embodiment, multiple techniques can be used to measure the polymerized additive layers. Different equal sets of measurement techniques can be used for different additive layers or different combinations of additive layer(s) and lens substrate. As a non-limiting example, surface reflectance techniques can be used to measure and calculate error for the first few layers, but transmittance measurement techniques can be used as a near-critical design step or layer design completion. additive to verify the optical through power of the lens (that is, the combined optical power change resulting when light is directed through the lens substrate and one or more of the additive layers applied to the lens substrate). The same or different measurement techniques can be used at different control points. In addition, the same or different measurement techniques can be used at one or more measurement locations for a given control point.
[0108]Non-contact measurement techniques are preferred to avoid damage to the polymerized additive layer. In a preferred embodiment, reflected light deflectometry is used for measurement. In another preferred embodiment, transmitted light deflectometry is employed. In another preferred modality, triangulation is used in reflected or transmitted modes. Control point measurements can be taken at one or more positions in the most recently deposited additive layer and can also be taken at one or more positions in the previous layers or lens substrate for comparative calculations.
[0109]With the reflected light measurements, mainly information about the polymerized additive layer is obtained. This information is combined with data about the lens substrate (and any previous additive layers) to determine how current results compare to expected results. With transmitted light measurements, information can be obtained directly or by calculating how the additive layer is combined with the lens substrate (and any prior additive layers) to change the properties of the lens substrate.
[0110] In a preferred embodiment, a camera is mounted in a known position different from the irradiation light source and used for measurement in step 700. An example of this is illustrated in Figure 2 for an irradiation beam 31 and a camera 41. In another preferred embodiment, a projector (R, G, B) is used, in which the blue light from the projector operates as the radiation source and the radiation polymerizable material is not affected by green or projector red. Instead, the camera uses the projector's green and red channels as its light sources to measure the optical properties of the applied layer and the three-dimensional shape of the layer relative to the lens surface or previous layers.
[0111] In a preferred embodiment, the lens substrate and its polymerized additive layer or its polymerized additive layers are not moved to a new position for these setpoint measurements. In situ measurement may be desirable to avoid repositioning errors. In such measurement systems, unpolymerized liquid can be drained out, removed by rotation, or otherwise removed from the polymerized layer and lens substrate surfaces prior to measurement in step 700, if desired. In another embodiment, uncured material is not removed during measurement at a control point. Instead, the measurement technique is designed to discriminate between the liquid layers and the additive layer(s). For example, the measurement technique can detect when all the liquid material that is probed has been converted to polymerized material; this may be possible, for example, when the liquid material has different refractive index, reflectivity or transmissivity properties than the polymerised material.
[0112] In another embodiment of the invention, the lens substrate with its polymerized layer will be moved to a different position preferably fixed for step 700 measurements. This may be preferable for accommodating some types of measurement devices, in particular, with optical through power measurements that may not be adaptable or convenient for position around liquid application equipment.
[0113] It will be important for accuracy and reproducibility that any measurement system used accurately and repeatedly identifies the positions of layers and substrate. This is important to determine if the additive layers are being applied and cured in the correct areas according to the additive layer design and for the projected parameters. If there is very high inaccuracy in specimen placement for a control point measurement, an individual cannot determine if an error is caused by erroneous placement of the additive layer or simply by measuring in the wrong area on the custom spectacle lens.
[0114]These measurements will be used to compare the actual change caused by the polymerized layer with the additive layer design and the expected results for the applied polymerized additive layer. Calculations of the error or difference between actual results and the project are then performed.
[0115] An advantage of this method of the invention of applying additive layers is that it is not dependent on the general dimensional accuracy of each applied layer as on the slope and localized thickness of the layer. A slight unevenness at a small point in an additive layer can be smoothed out during subsequent liquid layer applications or corrected (if necessary) by review or control point measurements. This is a distinct difference from previous thin-film additive processing used for spectral filtering, which requires and expects uniform changes over an entire surface, rather than localized positional control for specific optical power changes in a given area. In particular, when multiple additive layers are used to create the custom lens, the invention will allow for wider tolerances in the manufacturing process; measurements and recalculations at control points are used to adjust subsequent additive layers for any previous unacceptable errors. Advantageously, these control points and recalculations allow an individual using the inventive method to compensate for errors in individual layers and prevent the accumulation of errors like the custom spectacle lens from being built.
[0116] In step 800 of Figure 1B, the errors (if any) measured in step 700 are compared to the error limits established by the user of this invention. These error limits can be included for reference and for use in optimization within the additive layer design calculation in step 200, in step 700 calculations, or can be manually compared to expected results from a separate measurement. If the measurements are within the accepted error range, an individual continues with step 900. If the error is greater than acceptable values, then proceeds to step 820.
[0117] In step 820, if necessary, corrective measurements are determined for the additive layer design. This may involve another iteration of optimization calculations based on the current properties of the cured layer or cured layers and may produce a revised additive layer design. Values for zL-1(x, y) to be used in computing a revised tL(x, y) for a revised additive layer design can be derived or obtained from direct measurement of the actual lens substrate surface and /or one or more previous additive layers at the measurement location control point(s). In addition, the calculation can use estimates based on the number of layers already added according to the additive layer design or the number of layers added since a previous control point.
[0118]The corrective measures for the additive layer project are then planned and selected for implementation in a revised additive layer project. For example, if the error showed that the polymerized material was deposited in a very thick layer, another thinner layer could be applied to accommodate the previous error. In another example, if the polymerized material is present in an area of the lens substrate that was not originally intended for that additive layer (for example, if some droplets splash onto another area), it may be possible to correct by applying a layer subsequent with a different refractive index or with improved optical properties to hide this error. Other corrections encompassed by the invention should be recognized from these examples by a person of skill in the art. The calculation methods used for the optimization and the review cloth can be selected from those mentioned above, such as ray tracing, wavefront propagation analysis, Zernike's multidimensional polynomial-fitting and curvature calculation, or other methods known in the art that can be employed.
[0119] In step 820, settings are determined for the next polymerized layer or polymerized layers to be applied. In a preferred embodiment, these adjustments can be incorporated into changes to one or more additional additive layers of the project. This may be desired if a large change is required or if it is more easily accommodated by multiple radiation polymerizable materials or multiple additive layer applications.
[0120]The adjustments in step 820 may include changes to the position, thickness and/or slope of the next additive layer or next additive layers. In another modality, the total number of additive layers can be adjusted. In another preferred embodiment, the adjustments may comprise changes to the radiation polymerizable material and/or its components to one or more subsequent additive layers. In another preferred embodiment, selective irradiation for the next additive layer or subsequent additive layers can be modified to effect revisions at step 820; changes in irradiation can be employed alone or in combination with applied layer changes.
[0121]Once the desired settings for the next layer or additive layers have been determined in step 820, one proceeds to step 1000 of Figure 1B.
[0122]As described above, the route from step 820 is followed if a very large error has been measured and calculated in step 800. An alternative route is followed to step 900 if the error (if any) is measured for the layer polymerized additive deposited in step 800 was within acceptable limits or if there is no control point after irradiation of the applied layer (step 600). In these instances, one proceeds to the decision point in step 900 for additional applied liquid layers. One layer may be enough to create the desired new properties for the custom eyeglass lens. However, the in-ventors chose to measure the result (step 700) even with a one-layer design and confirmed that the current performance of the custom lens was in line with the expected design results. Therefore, for a one-layer design according to the invention, steps 500, 600, 700, and 800 will be followed and, if necessary, an adjustment through steps 820 and 1000 will be performed if required. On the other hand, the additive layer design of step 200 may require one or more additional additive layers to reach the custom spectacle lens. Step 900 describes this project query to see which series of next steps to follow.
[0123]If no additional polymerized layers are required by the additive layer design to produce the desired custom lens properties, one proceeds to the end of the process. Optional step 920 recognizes that other coatings can be added to the custom lens after the additive layer design is complete. Examples of some other coatings include: hard coating or abrasion resistant coatings, smoothing coatings, photochromics, coatings to improve cleanability, polarized coatings, and conductive coatings or active coatings for display applications. These can be applied by various known techniques, which include gaseous or liquid phase deposition. Exemplary additional coatings which are in particular suitable for gas phase deposition techniques (such as chemical or physical vacuum, plasma, corona, atmospheric or steam deposition) include anti-reflective coatings, coatings of filter and conductive coatings. These and other coatings can be applied alone or in combination to provide optional additional lens features.
[0124]In addition, the optional coatings in step 920 can include other features added to the lens on, with, over or inside the coatings. Examples of some of these features include decorative prints; stickers; jewelry; embedded chips, displays or sensors; micro-optics and semi-visible markers for lens identification.
[0125]Optional step 940 can be used if desired for lens post-cure. Post-cure can be used to temper, stabilize, release material tension, densify or improve the final properties of the applied additive layers and custom lens. In a preferred embodiment, post-cure exposure to heat and light can reduce the yellowness of some polymerized materials. In another preferred embodiment, a post cure can reinforce the integral bonding of the additive layer(s) to the lens substrate and/or each other. A post-healing step may involve general exposure of the lens to broad-spectrum thermal form, infrared form, or other forms of energy, or controlled exposure to a specific wavelength or energy range. This is sometimes used as a finishing step in eyeglass lens production.
[0126] At this point, when the last additive layer has been applied and irradiated according to the additive layer design (the original design or as revised based on the control point measurement) and any optional steps have been performed, the custom lens production according to the invention is completed.
[0127] In another embodiment of the invention, if the additional polymerized layers are part of the additive layer design (as required in step 900), one proceeds with step 1000. The radiation polymerizable material applied in step 1000 may be the same as that applied in step 300.
[0128] Alternatively, in another preferred embodiment, the radiation polymerizable material applied in step 1000 may comprise a radiation polymerizable material different from that applied in step 300. In another preferred embodiment, the radiation polymerizable material of the layer or bed. of the additional ones comprise components different from that of the first applied layer. In another preferred embodiment, the radiation polymerizable material of additional layer(s) has physical or optical properties measurably different from the first radiation polymerizable material. The subsequent layers may each comprise radiation polymerizable materials and/or components different from those of the preceding layers or may be the same as the one or more prior layers. Such variations are within the scope of the invention and are understood by one skilled in the art.
[0129] Additional layers of liquid polymerizable materials can be applied to the above radiation-cured additive layers, to portions of the original lens substrate surface where the additive layers have not previously been applied, or to the original substrate surfaces where the layers not previously applied. In another preferred embodiment, the layer applied in step 1000 can be transposed through a combination of both the original lens substrate and one or more previously applied additive layer(s). For ease of reference, these options and other variations to describe how additional liquid layers are present on the lens substrate and/or portions of any prior additive layers or all prior additive layers are referred to as application zones. An application zone identifies where an additional layer of liquid is applied or has spread prior to its selective irradiation. For example, after a first layer of liquid has been applied and irradiated to form a first additive layer, a second layer of liquid can be applied to an application zone comprising at least a portion of the first lens substrate surface, at least a portion of the second lens substrate surface, at least a portion of the first additive layer, or a combination of at least a portion of one of the lens substrate surfaces and a portion of the first additive layer. In a similar manner, additional liquid layers can be applied, for example, in application zones which comprise portions of one or more of the surfaces of the lens substrate, portions of one or more previously applied additive layers, such combinations. a portion of a lens substrate surface or a portion of a previously applied additive layer or combinations of portions of two or more previously applied additive layers and a portion of a lens substrate surface. The same application zone can be used for multiple subsequent liquid layers or different application zones can be employed.
[0130]The final area of the additive layer produced from the liquid layer will, in most cases, occupy an area equal to or smaller than the application zone. The final area of an additive layer will depend on both the application zone and the selective irradiation of a layer of additive layer precursor liquid; the additional additive layer of the invention is selectively and only formed in its selected area of controlled irradiation. In addition, the controlled irradiation of the liquid layer will integrally bond the resulting additive layer in the selected area of controlled irradiation to the previous layer(s) and/or lens substrate surfaces constituting the application zone. in that area.
[0131]Some examples of the various placements of the additive layers resulting from the zones of application of multiple layers of liquid are illustrated in Figure 2. The additive layer 51 is shown in its integrally bonded position on a portion of the surface of the lens substrate 11. Exemplary additive layer 52 was polymerized (as indicated by horizontal fill markers) onto a portion of additive layer 51 and a portion of the lens substrate surface 11. This is an example of a layer connection across structures. above. Exemplary layer 53 is shown as it is being processed in accordance with an embodiment of the invention, which includes areas 53a, 53b and 53c. In this example, the lens substrate is being moved during irradiation in at least one positive y-axis direction (which moves to the right in the drawing); it can also be subjected to movement in the z direction and translational or rotational movement in the x direction. The portion of the layer 53 to the left of the irradiation beam (53a) is still a layer of liquid, as indicated by dashed line markings like those of the radiation polymerizable liquid material shown below the lens substrate at 21. layer 53 directly under irradiation beam 31 (area 53b, shown hatched) is being polymerized by selective radiation. Area 53c to the right in Figure 2, where layer 53 is shown with horizontal fill markers, indicates the area of the applied liquid layer that has already been converted to a polymerized additive layer through exposure to the radiation beam 31. A layer 53, in this example, was applied over a portion of the front additive layer 52, which may comprise radiation polymerized materials (or components) the same or different from those of any layer 51 or 53.
[0132]Additional layers of radiation polymerizable material, applied according to the additive layer design, can serve multiple purposes. For example, an additive layer can be positioned and designed to smooth out the edge effects in the previous additive layers as well as contribute to the optical power of the custom spectacle lens. In this embodiment of the invention, the additive layer which also functions as a smoothing layer may, for example, be thinner or may have a lower viscosity or lower surface tension than previous layers, so that it spreads over the edge of the layers. or from the previous additive layer and smooth the layered contours. This can also be accomplished by applying the additive smoothing layer at a slightly different location on the lens from the previous layers. In a preferred embodiment, the refractive index of the additive smoothing layer(s) is compatible with the previous additive layer or layers to reduce optical interference effects. Also, it can be useful to create the additive layer design as a combination of thinner layers interspersed with thicker layers to reduce boss heights at the edges of additive layers.
[0133]Additional additive layers can also be designed to provide new areas on the custom lens surface with properties different from those provided by the substrate or previous additive layers. An example of this would be where the first additive layer applied has an index of refraction and creates an optical power by its addition to the lens substrate, while the layer applied in step 1000 comprises radiation polymerizable components and/or material that will create an index of different refraction and a different optical power in the regions where they are applied.
[0134]After applying the next layer of liquid in step 1000 of Figure 1B, proceed with either the optional measurements or the subsequent optional actions outlined in steps 320, 330 and 340 or proceed to step 400. If the optional steps 320, 330 and 340 are followed, measurements can evaluate the properties and position of the liquid layer applied in step 1000 in relation to the lens substrate and/or in relation to the previously applied additive layer(s) (s).
[0135] In step 400, the radiation can have a frequency equal to or different from that used for the first layer and can be controlled to equal or different values of the wavelength range, spatial distribution and energy to form the layer(s) (s) additional polymerized additive(s). These controlled parameters will be determined by the radiation polymerizable materials that are used for the layers, as well as the layer position, thickness and/or individual slope. For example, energy other than radiation may be required if the layer applied in step 1000 is applied over a previous additive layer that is reflective rather than a material that is transparent for that wavelength range; the reflective layer can effectively allow a double exposure of the liquid layer in the irradiation area and therefore less energy can be required in such areas. Furthermore, the irradiation will be controlled to form the additive layer from the liquid layer only in the selected area, to form the additive layer according to the additive layer design and to integrally bond the additive layer to its application zone. The selected area of any given layer of liquid that is radiated will be specific to that layer, but may form the additive layer from its precursor liquid layer at the same or different location as previous additive layers, depending on the layer design requirements additive.
[0136] As indicated, the sequence of steps can proceed for more than two layers of liquid and will depend on the design generated in step 200, with any revisions that occurred, for example, in steps 340 or 820. The sequence is repeated until there are no more additional layers indicated in step 900, at which point it proceeds through optional steps 920 and 940 to complete the process of the invention.
[0137] In another preferred embodiment, a layer comprising a photoinitiator is applied immediately before or after step 300 or immediately before or after step 1000. (This action is not included in the flowchart of Figure 1A and Figure 1B .) The layer comprising the photoinitiator may comprise material compatible with the radiation polymerizable material(s) to be used in the process and capable of integrally binding to the s) same(s). In one embodiment, the photoinitiator-comprising layer may be very thin so that it does not affect the overall optical power of the additive layer design. These optional photoinitiator layers are a preferred addition of the in-ventors to control and improve the depth and extent of cure of adjacent radiation polymerizable layers.
[0138] In another embodiment of the invention, a first layer can be applied before the one or more liquid radiation polymerizable layers that will form the additive layers are applied. Such first layers can improve adhesion, or alleviate thermal expansion or stress mismatch, between the lens substrate and subsequent additive layers or between stacked additive layers.
[0139]When the custom spectacle lens is completed, it can be attached to the individually chosen spectacle frame. You may need to bevel the custom spectacle lens to your final size to accomplish this step. Alternatively, in a preferred embodiment of the invention, the lens substrate is beveled to engage the frame prior to carrying out the additive layer process; this simplifies the assembly of the final glasses. In another preferred embodiment, the lens substrate and the spectacle frame are fitted together prior to the inventive process and the entire spectacle assembly proceeds through the additive layer applications. In this embodiment, if desired, additive layers can be applied to the spectacle frame as well as the lens substrate for improved or new features. In another preferred embodiment, the additive layer process can create the spectacle frame to be used with the custom lens.
[0140] In another embodiment of the invention, if the additive layer design is generated to convert the lens substrate optical power into a desired set of optical powers for the custom spectacle lens comprising intermediate optical power values, it may be necessary to finish the fine polish or smooth the custom eyeglass lens before insertion into the eyeglass frame. This embodiment of the invention may be practical, for example, when the customized spectacle lens is to be transported to a final destination and may be scratched with transporting the same; the final finish after producing the custom lens can be more effective and more costly than complicated handling and packaging.
[0141] In another embodiment, the additive layer design can convert the optical power properties of the lens substrate to a set of desired optical properties for the custom spectacle lens and convert other lens substrate properties into additional intermediate properties for the custom lens. As an example, the additive layer design may comprise radiation polymerizable components or material that add scratch resistant, polarized or photochromic performance to the custom lens in addition to optical power changes. A custom spectacle lens such as this example may be optional and additionally coated in step 920 with layers of smoothing, AR coatings or other coatings to complete the functional or protective attributes of the custom spectacle lens.
[0142]These variations and configurations are not comprehensive of all possible modalities, but provide examples that are within the scope of the invention and that an individual skilled in the art would recognize.
[0143] The invention will now be described in more specific details with reference to the following non-limiting examples. EXAMPLE 1
[0144]A finished lens substrate with more power is retained in a fixed mount so that the concave surface is exposed. (The concave surface of the lens substrate is the surface that will be closest to the eye when the custom lens is used.) In this Example, an additive layer design is generated with successive additive layers approximately 10 micrometers apart. thickness each composed of a radiation polymerizable material to be deposited on the concave surface of the lens substrate using a spray coating mechanism. The purpose of the additive layer design in this Example is to form a region of added optical power of +2.00 diopters located in a portion of what will be the lower half of the custom spectacle lens when it is mounted to its frame. In this Example, if a lens substrate with a refractive index of n=1.5 is used and if the additive layers comprised the radiation-cured material that has a refractive index of 1.5, then 200 additive layers approximately 10 micrometers thick each will need to be applied to create a region with an optical power of +2.00 diopters. In this example, the liquid layer applied by the spray coating will need to be somewhat thicker than 10 micrometers to allow for evaporation and densification under irradiation to form the integrally bonded and polymerized material of the additive layer.
[0145]Each layer of liquid is irradiated with a projected pattern, made using a UV laser light source and a digital light processing projector, to create the radiation-cured additive layer of material. The radiation polymerizable material is selected so that it forms an integral bond with the lens substrate and with successive polymerized additive layers. A Shack-Hartmann sensor is used to measure the local curvatures in the polymerized and deposited layer and is compared to the expected results for each additive layer.
[0146] In this Example, the first layer is applied to approximately one half of the concave surface area of the finished lens substrate. (This half of the lens substrate will match the lower half of the resulting custom spectacle lens as mounted on the final spectacle frame.) The projected pattern of UV radiation creates a pattern of integrally polymerized material bonded to the lens substrate. For this Example, the projected pattern is chosen as an irradiation beam that is circular in shape and is directed into the liquid layer in a selected area to create a circular area of radiation polymerized material, ie at least 8 mm of diameter and centered at least 8 mm below the center of the lens substrate on its concave surface. For this Example, the selected radiated area (which creates the additive layer of polymerized material) is smaller than the total area to which the liquid layer is applied. Uncured material is washed off the substrate.
[0147] At the control point for this Example, the concave surface with the additive layer is measured with a Shack-Hartmann type sensor to compute the curvatures of the current concave surface after applying the last additive layer, which is designated as N-1 . The measured result is compared to the additive layer design calculated in layer N-1 and the geometry of the following layers is compensated so that the required curvature of layer N (the next layer to be applied) is set to be: (a projected curvature for layer N) - (the error curvature of layer N-1).
[0148]Using the error fit found by the measurement, the next layer of radiation polymerizable material is applied by spray coating over the same area as the previous layer of liquid. In this Example, the next area of liquid layer will extend beyond the edges of the previously polymerized additive layer. This next layer of liquid is irradiated with the same radiation pattern as the first layer to create another additive layer on top of the previous additive layer of the radiation-cured material. Measurement using the Shack-Hartmann sensor is used to confirm the results or generate adjustments for the next additive layer to be applied. This process is repeated for multiple layers until the desired additional power of +2.00 diopters in the area of the additive layers of this custom spectacle lens is achieved.
[0149]In the Example, each tenth layer is radiated with another projected light pattern that extends beyond the area of the circular radiating beam, to create a slightly larger additive layer for edge leveling purposes. EXAMPLE 2
[0150] A finished flat lens substrate with a polished and finished convex surface is attached to a support mechanism so that the concave surface is exposed for the additive layer process in a configuration such as that illustrated in Figure 2. The volume of layers to be built on top of the initial substrate is computed as a series of successive layers of different thickness so that each individual layer is not thicker than 100 micrometers at any point.
[0151]Blue light from a projector (R, G, B) is used to selectively irradiate and polymerize the radiation polymerizable liquid material for additive layer design. The green and red channels are specifically chosen to have wavelength distributions outside the range that can cause the material to react or polymerize.
[0152]Before being attached to the support mechanism, the convex surface of the lens is covered with a plastic film (not shown in Figure 2) which is opaque in the blue light that is used for polymerization. This protects the convex surface of the lens substrate from being altered during the additive layer process. The support mechanism is designed to allow movement of the lens substrate 11 in the Y and Z directions with an accuracy of 1 micrometer. The support mechanism can also rotate the lens substrate around the X axis at an angle A that has an accuracy of 1 mrad.
[0153] The support mechanism will introduce the lens into a tank holding a radiation polymerizable liquid material 21. The position of the lens substrate (Y, Z, A) is known at any time and follows a trajectory that has been computed for each layer to be applied on the concave surface of the lens. The trajectory estimates the contact point of the liquid surface with the concave lens surface at any time t. The trajectory also estimates the contact angle of the concave surface with the liquid.
[0154]The projector (R, G, B) is mounted in a vertical position (shown as beam 31 in Figure 2) in relation to the tank holding the radiation polymerizable liquid material 21.
[0155] A camera (41 in Figure 2) is mounted in an oblique position relative to the tank holding the radiation polymerizable liquid material 21. The green and red channels of the projector and the camera are used as a triangulation system with use of structured light patterns to measure the three-dimensional shape of the liquid surface around the estimated contact zone between the irradiation beam 31 and the liquid layer (53) or the three-dimensional shape of the additive layers in the region of intersection of the beam 31 and the camera's viewing zone 41. The camera and projector system incorporates focusing and projection optics, respectively, to ensure that the measurement field is approximately 5 mm along the Y direction and 20 mm along the along the X direction. The measurement of the coordinates (X, Y, Z) of the liquid layer (as in step 320 of Figure 1A) or of the additive layer(s) (as in step 700 of the Figure 1B) can be achieved with an accuracy of 1/1000 of the measurement field.
[0156] The smoothness of each of the layers that is built is achieved by the constant movement of the lens during the irradiation process and by the combination of different additive layers that are built with different orientations (angle A) due to different irradiation distributions in relation to the liquid surface applied to each point (X, Y, Z). Smoothness can also be achieved by different positions of subsequent additive layers relative to the location on the lens substrate surface or on the previous additive layers.
[0157] In this arrangement, both on the surface of the liquid layer (as in step 320 of Figure 1A) and on the surface of the polymerized additive layer(s) (as in step 700 of Figure 1B) are non-contact measurements using the same camera projector 3D recording mechanism. In the case of measuring the polymerized additive layer, the radiation polymerizable liquid material 21 can be recessed, as shown in Figure 2, below the area of the polymerized additive layer.
[0158]The measurements are taken after each layer or after each of the N layers. The errors detected in the surface will be used to calculate the adjustments of the next layers to be applied to build the desired total design. EXAMPLE 3
[0159] In another embodiment, the support mechanism and immersion method of EXAMPLE 2 is used with a different measurement system and light source. For example 3, an extended structured light source such as an LCD screen is used for irradiation. The camera and extended light source measure the liquid surface near the concave surface of the lens substrate by triangulation. In addition, the camera and extended light source are used to measure the shape of the polymerized additive layers for any errors and the position, thickness or slant of the next layers of the additive layer design are adjusted based on the calculated errors. .
[0160] Although the invention has been disclosed in detail with reference to preferred embodiments and multiple variations or derivatives of those embodiments, a person skilled in the art will appreciate that additional substitutions, combinations and modifications are possible without departing from the concept and scope of the invention . These variations and similar variations would become clear to an individual of ordinary skill in the art upon inspection of the specification and drawings in this document. Accordingly, the invention is identified by the following claims.

权利要求:
Claims (19)
[0001]
1. Method of producing a custom spectacle lens CHARACTERIZED by the fact that it comprises: a) obtaining a lens substrate comprising a first surface closer to the eye when used and a second surface further away from the eye when used, in that the lens substrate comprises optical power properties that are perceptibly different to the naked eye from the optical power properties of the custom spectacle lens; b) calculate the total modification required to convert the optical power properties of the lens substrate into a desired set of optical power properties for the custom spectacle lens, generate an additive layer design comprising two or more additive layers to achieve the total calculated modification and identify at least one control point with error limits for confirmation or revision of the additive layer design; c) applying a first layer of liquid comprising a first radiation polymerizable material to at least a portion of one of the surfaces of the lens substrate; d) radiating a selected area of the first layer of liquid with radiation that is controlled for the wavelength, spatial and energy distribution range to form the first additive layer by polymerization only in the selected radiated area, wherein the first layer of liquid is irradiated according to the additive layer design, and wherein the first additive layer is integrally bonded to the lens substrate; e) applying a second layer of liquid comprising a second radiation polymerizable material to a first application zone selected from the group consisting of at least a portion of one of the surfaces of the lens substrate, at least a portion of the first layer additive or a combination of both a portion of a lens substrate surface and a portion of the first additive layer; f) radiating a selected area of the second layer of liquid with radiation that is controlled over the wavelength, spatial and energy distribution range to form a second additive layer by polymerization only in the selected area of the irradiated second layer of liquid, wherein the second layer of liquid is irradiated according to the additive layer design and wherein the second additive layer is integrally connected to the first application zone, eg) carry out the following steps at at least one control point, h) ) measure a or more localized properties comprising at least the localized slope of at least one of the selected layers of the first liquid layer, of the first additive layer, wherein the measurement of localized slope is made at one or more measurement locations; i) ) calculate the error between the measured located properties and expected results for the additive layer design at each measurement location; j) ) compare the error to the error limits of at least one control point, and k) ) review the additive layer design if the error is greater than the error limits of at least one control point, where the method of application of each of the first and second liquid layers are selected from the group consisting of spin coating, dipping, spraying, rolling, sheeting and curtain coating.
[0002]
2. Method according to claim 1, CHARACTERIZED in that it further comprises: h) applying one or more additional liquid layers comprising radiation polymerizable material to an application zone selected from the group consisting of at least a portion of one of the surfaces of the lens substrate, at least a portion of the first additive layer, at least a portion of the second additive layer, a combination of both a portion of a lens substrate surface and a portion of the first additive layer , a combination of both a portion of a lens substrate surface and a portion of the second additive layer, a combination of both a portion of the first additive layer and a portion of the second additive layer, and a combination of a portion of a surface of lens substrate, a portion of the first additive layer and a portion of the second additive layer, wherein the method of applying one or more liquid layers to is selected from the group consisting of rotating, dipping, spraying, rolling, blade and curtain coating and i) radiating a selected area in each of the one or more additional liquid layers with radiation that is controlled to a range of wavelength, spatial and energy distribution to form an additional additive layer by selectively polymerizing each additional liquid layer, where each additional additive layer is formed only in the selected area where each additional liquid layer is irradiated, where the one or more additional liquid layers are irradiated according to the additive layer design and each additional additive layer is integrally bonded to its application zone.
[0003]
3. Method according to claim 2, characterized in that the irradiation of a selected area of at least one of the additional liquid layers further comprises forming at least one additional additive layer, so as to smooth the selected characteristics from at least one edge of the first additive layer, at least one edge of the second additive layer, at least one edge of an additional additive layer, discontinuities in a portion of at least one surface of the lens substrate, and irregularities in a portion of at least one lens substrate surface.
[0004]
4. Method according to claim 1, CHARACTERIZED by the fact that the lens substrate is selected from finished lens blank blocks, semi-finished lens blank blocks, flat lens blank blocks, flat bevel lenses, and finished beveled lenses.
[0005]
5. Method according to claim 1, CHARACTERIZED in that the one or more localized properties are selected at each measurement location further comprise one or more additional localized properties selected from the group consisting of the height, optical power and position of the additive layers present at the measurement location and the optical through power of combustion of the lens substrate and additive layers present at the measurement location.
[0006]
6. Method according to claim 1, CHARACTERIZED in that the first radiation polymerizable material and the second radiation polymerizable material are the same radiation polymerizable material.
[0007]
7. Method according to claim 1, CHARACTERIZED by the fact that the first radiation polymerizable material comprises components different from that second radiation polymerizable material.
[0008]
8. Method according to claim 1, CHARACTERIZED by the fact that the first radiation polymerizable material comprises components selected from the group of photoinitiators, UV absorbers, infrared reflectors, visible tints, dyes, pigments, photochromic agents, agents thermochromics, electrochromic agents, polarizers, thermal stabilizers, electrically conductive materials, liquid crystal materials, light-absorbing particles, light-reflecting particles, sensors, transmitters and displays.
[0009]
9. Method according to claim 1, CHARACTERIZED by the fact that the first additive layer has measurably different properties from the lens substrate and the measurably different properties are selected from the group consisting of refractive index, Abbe value, abrasion resistance, impact resistance, resistance to organic solvents, resistance to bases, Tg, visible transmittance, UV transmittance, polarization and photochromic properties.
[0010]
10. Method according to claim 1, CHARACTERIZED by the fact that the first layer of liquid is applied to the first surface of the lens substrate.
[0011]
11. Method according to claim 1, CHARACTERIZED by the fact that the first layer of liquid is applied to both the first and second surfaces of the lens substrate.
[0012]
12. Method according to claim 1, CHARACTERIZED by the fact that the method of irradiating a selected area of the first liquid layer forms the first additive layer on only a portion of one of the surfaces of the lens substrate.
[0013]
13. Method according to claim 1, CHARACTERIZED in that the method of irradiating a selected area of the first or second layer of liquid further comprises moving the lens substrate in at least one selected direction from the translation in Y, Z translation and rotation.
[0014]
14. Method according to claim 1, characterized in that it comprises applying a layer comprising a photoinitiator.
[0015]
15. Method according to claim 1, CHARACTERIZED by the fact that the wavelength range of the radiation used in phases d) and f) is selected from the group consisting of microwave, radio frequency, ultraviolet, visible radiation and radiation infrared.
[0016]
16. Method according to claim 1, CHARACTERIZED by the fact that irradiating a selected area of the second layer of liquid additionally comprises forming the second additive layer so that it smoothes with respect to selected features from at least an edge of the first additive layer, discontinuities in a portion of at least one surface of the lens substrate, and irregularities in a portion of at least one surface of the lens substrate.
[0017]
17. Method according to claim 1, CHARACTERIZED by the fact that the additive layer design further comprises modifying one or more properties for the custom lens selected from polarization, photochromicity, UV transmittance, visible transmittance, light reflectance , hydrophobicity, chemical resistance, abrasion resistance, impact resistance and electrical conductivity.
[0018]
18. Method according to claim 17, CHARACTERIZED by the fact that the number of additive layers in the additive layer design comprises at least 200 layers.
[0019]
19. Method according to claim 1, CHARACTERIZED by the fact that the number of additive layers in the additive layer design comprises at least 50 layers.

类似技术:

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公开号 | 公开日 | 专利标题

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BR112016022180B1|2021-06-22|GLASSES LENS PRODUCTION BY MULTI-LAYER ADDITIVE TECHNIQUES

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US9952448B2|2018-04-24|Eyewear lens production by additive techniques

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EP3218166B1|2019-03-13|Eyewear lens production by additive techniques

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US8953176B2|2015-02-10|Laser confocal sensor metrology system

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KR102188864B1|2020-12-09|Process and system for manufacturing an ophthalmic lens

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KR102188874B1|2020-12-09|Process and machine for manufacturing an ophthalmic lens

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JP4778907B2|2011-09-21|Glasses manufacturing method

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KR20160029107A|2016-03-14|Method for manufacturing at least one ophthalmic lens

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KR20070095867A|2007-10-01|Method of manufacturing am optical lens

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US20050105043A1|2005-05-19|Eyeglass dispensing method

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JP2007514963A5|2009-06-18|

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KR102014058B1|2019-08-27|Method and apparatus for providing variations of a lower-lid contact surface and under-lid support structures of a translating multifocal contact lens

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WO2022002344A1|2022-01-06|System for marking a coated ophthalmic lens

同族专利:

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公开号 | 公开日

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CA2937728A1|2015-10-29|

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US20150276987A1|2015-10-01|

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CN106164753A|2016-11-23|

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US9933632B2|2018-04-03|

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EP3122545A1|2017-02-01|

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JP2017516155A|2017-06-15|

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WO2015162498A1|2015-10-29|

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法律状态:
2019-12-24| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|

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2021-05-25| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|

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2021-06-22| B16A| Patent or certificate of addition of invention granted [chapter 16.1 patent gazette]|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 26/03/2015, OBSERVADAS AS CONDICOES LEGAIS. |

优先权:

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申请号 | 申请日 | 专利标题

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US14/226,686|US9933632B2|2014-03-26|2014-03-26|Eyewear lens production by multi-layer additive techniques|

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US14/226,686|2014-03-26|

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PCT/IB2015/001351|WO2015162498A1|2014-03-26|2015-03-26|Eyewear lens production by multi-layer additive techniques|

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