Ophthalmic lenses with printed enhancement

Abstract

A printing system for optically enhancing a deposition substrate to produce an ophthalmic lens comprises a receptacle for receiving the deposition substrate, an inkjet printing head for depositing drops of a curable ink onto a surface of the substrate, and a computerized control system. The control system is operative to define a printing volume bounded by a target surface shape and a non-planar shape of the first major surface, divide the printing volume into a set of vertically ordered printing layers, each layer defining a set of drop locations having respective x-y coordinates, and causing the inkjet printing head to deposit the printing layers onto the first major surface of the deposition substrate in a sequence that is ordered differently than the set of vertically ordered printing layers, the deposited printing layers comprising drops of the curable ink.

Description

[0001] OPHTHALMIC LENSES WITH PRINTED ENHANCEMENT

[0002] CROSS-REFERENCE TO OTHER PUBLICATIONS

[0003] This application claims priority from UK patent application no. GB2416828.8 filed on November 15, 2024, from UK patent application no. GB2416822.1 filed on November 15, 2024, the teachings of both of which are incorporated herein by reference in their entirety.

[0004] FIELD OF THE INVENTION

[0005] The present invention relates to methods, apparatus and systems for fabricating optical articles, and particularly to optical articles formed, inter alia, by drop deposition of curable compositions, including, without limitations, radiation-polymerizable compositions, on a substrate.

[0006] BACKGROUND

[0007] Eyeglass lenses are currently produced in a variety of different processes. A common method for producing an eyeglass lens in an optical laboratory involves first selecting a clear lens blank, which is obtainable commercially in a variety of diopters. The lens blanks are outsourced from large producers who produce them using molding and / or machining. Even a small laboratory must track and maintain inventories of a very large number of differently powered lens blanks. When tints and other coatings are involved, the number of different blanks increases even further. The work of the laboratory may involve measuring or scanning a selected eyeglass frame and trimming or edging the lens blank to fit the frame. Some methods include selecting and then machining a semi-finished or finished lens blank with a given base power, i.e., the curvature of a first surface, to produce a lens with the final diopter.

[0008] At present, there is no known practical approach that gives the optical laboratory more control over the production of the lenses, e.g., setting the optical power, customizing bi-focal, multi-focal and progressive lenses, addressing cylinder and prism, and so on. A practical approach is needed that would reduce the need to manage large, expensive inventories of prescription-specific lens blanks and that would allow the optical laboratory to control all or a large part of lens production while producing precise lenses in an expedited and less expensive manner.

[0009] SUMMARY

[0010] According to embodiments, a printing system for optically enhancing a deposition substrate to produce an ophthalmic lens comprises: (a) a deposition-substrate receptacle; (b) an inkjet printing head operable, in a first operating mode in which a deposition substrate has been received in or upon the deposition-substrate receptacle, to deposit drops of a curable ink onto a first major surface of deposition substrate; and (c) a computerized control system configured to regulate operation of the inkjet printing head. The control system is programmed or programmable to carry out the following steps: (i) defining a printing volume bounded by a target surface shape and a non-planar shape of the first major surface, (ii) dividing the printing volume into a set of vertically ordered printing layers, each printing layer defining a set of drop locations having ink quantity values at respective x-y coordinates, and (iii) when in the first operating mode, causing the inkjet printing head to sequentially deposit the printing layers onto the first major surface of the deposition substrate to form the target surface shape, the deposited printing layers comprising drops of the curable ink. The dividing is such that for respective drop locations of at least some printing layers, a first portion of the drop locations is arranged in an ordered distribution and a second portion of the drop locations is arranged in a stochastic distribution.

[0011] A method is disclosed, according to embodiments, for optically enhancing a deposition substrate to produce an ophthalmic lens. The method comprises: (a) receiving the deposition substrate, the deposition substrate comprising a first major surface having a non-planar shape; (b) defining a printing volume bounded by a target surface shape and the non-planar shape of the first major surface; (c) dividing the printing volume into a set of vertically ordered printing layers, each printing layer defining a set of drop locations having respective x-y coordinates; and (d) causing an inkjet printing head to sequentially deposit the printing layers onto the first major surface so as to form the target surface shape. The deposited printing layers comprise drops of a curable ink. The dividing is such that for respective drop locations of some printing layers, or of a majority of the printing layers, or of all of the printing layers, a first portion of the drop locations is arranged in an ordered distribution and a second portion of the drop locations is arranged in a stochastic distribution. The defining, dividing and causing being carried out by a programmed or programmable control system.

[0012] According to embodiments disclosed herein, a printing system for optically enhancing a deposition substrate io produce an ophthalmic lens comprises: (a) a deposition-substrate receptacle; (b) an inkjet printing head operable, in a first operating mode in which a deposition substrate has been received in or upon the depositionsubstrate receptacle, to deposit drops of a curable ink onto a first major surface of deposition substrate; and (c) a computerized control system configured to regulate operation of the inkjet printing head. The control system is programmed or programmable to carry out the following steps: (i) defining a printing volume bounded by a target surface shape and a non-planar shape of the first major surface, (ii) dividing the printing volume into a set of vertically ordered printing layers, each printing layer defining a set of drop locations having respective x-y coordinates, (iii) modifying at least two of the printing layers in at least one of the two following ways: (A) for a given pair of x-y coordinates, a defined drop location is removed from a first printing layer and added to a second printing layer, and (B) for a given pair of x-y coordinates, an ink quantity value of a defined drop location is reduced from a first printing layer and correspondingly increased in a second printing layer, and (iv) when in the first operating mode, causing the inkjet printing head to deposit the modified printing layers onto the first major surface of the deposition, the deposited modified printing layers comprising drops of the curable ink.

[0013] A method is disclosed, according to embodiments, for optically enhancing a deposition substrate to produce an ophthalmic lens to produce an ophthalmic lens. The method comprises: (a) receiving a deposition substrate comprising a first major surface having a non-planar shape; (b) defining a printing volume bounded by a target surface shape and the non-planar shape of the first major surface; (c) dividing the printing volume into a set of vertically ordered printing layers, each printing layer defining a set of drop locations having respective x-y coordinates; (d) modifying at least two of the printing layers in at least one of the two following ways: (A) for a given pair of x-y coordinates, a defined drop location is removed from a first printing layer and added to a second printing layer, and (B) for a given pair of x-y coordinates, an ink quantity value of a defined drop location is reduced from a first printing layer and correspondingly increased in a second printing layer; and (e) causing an inkjet printing head to sequentially deposit the printing layers onto the first major surface so as to form the target surface shape, the deposited printing layers comprising drops of a curable ink. The defining, dividing, modifying and causing are carried out by a programmed or programmable control system.

[0014] BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The invention will now be described further, by way of example, with reference to the accompanying drawings, in which the dimensions of components and features shown in the figures are chosen for convenience and clarity of presentation and not necessarily to scale. In the drawings:

[0016] Fig. 1 is a hybrid-view schematic illustration of selected elements of a printing system for optically enhancing a deposition substrate to produce an ophthalmic lens, showing the optically-enhanced deposition substrate in cross section, where the optically-enhancing deposition is on a concave surface according to embodiments of the present invention.

[0017] Fig. 2 is a schematic cross-sectional illustration of an optically-enhanced deposition substrate, where the optically-enhancing deposition is on a convex surface, according to embodiments of the present invention.

[0018] Fig. 3 is a schematic cross-sectional illustration of the optically-enhancing deposition of Fig. 1, according to embodiments of the present invention.

[0019] Fig. 4A is a schematic cross-sectional illustration of a plurality of deposited printing layers making up the optically-enhancing deposition of Fig. 1, according to embodiments of the present invention.

[0020] Fig. 4B shows the printing layers making up the optically-enhancing deposition of Fig. 1 deposited in reverse order, according to embodiments of the present invention.

[0021] Fig. 5 schematically shows the modification of printing layers by virtually moving ink quantity from one layer to another for a given pixel, according to embodiments of the present invention. Figs. 6 and 7 show schematic illustrations of printing layers having respective first portions with ordered drop distribution and respective second portions with stochastic drop distribution, according to embodiments of the present invention.

[0022] Fig. 8 shows schematic illustrations of drop distribution in printing layers having respective first portions with ordered drop distribution and respective second portions with stochastic drop distribution, according to embodiments of the present invention.

[0023] Fig. 9 is a block diagram of a printing system for optically enhancing a deposition substrate to produce an ophthalmic lens, according to embodiments of the present invention.

[0024] Fig. 10 is a block diagram of a control system for the printing system of Fig. 9, according to embodiments of the present invention.

[0025] Figs. 11 and 12 show flowcharts of methods for optically enhancing a deposition substrate to produce an ophthalmic lens, according to embodiments of the present invention.

[0026] DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

[0027] The invention is herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice. Throughout the drawings, like-referenced characters are generally used to designate like elements.

[0028] Embodiments of the invention relate to ophthalmic lenses for eyeglasses, produced by optically enhancing a deposition substrate. In embodiments, the substrate comprises a polymer. The optical enhancement is carried out by printing layers of a curable ink, e.g., by inkjet printing or micro-jetting (single-nozzle jetting), on an optical-grade substrate. The printed layers thus make up the ‘optical enhancement’ as the term is used herein. In some examples, the deposition substrate (or, simply, ‘substrate’) comprises a single-vision lens blank having a non-zero optical power. The single-vision lens blank can be a meniscus lens, i.e., concave-convex, in which case the printed layers are deposited at least on the concave surface. In some such examples, the substrate, the printing of the layers can produce an enhanced ophthalmic lens comprising, and not exhaustively: a bifocal lens, a multifocal lens or a progressive lens.

[0029] In some examples, the substrate comprises a curved printing surface but has substantially zero optical power, or alternatively, a lower optical power than is required in a final prescription.

[0030] In some examples, the substrate comprises a lens blank with some but not all of the ophthalmic features required by an eyeglass prescription. In some such examples, the substrate, the printing of the optically enhancing layers can produce, and not exhaustively, a bifocal lens, a multifocal lens, a progressive lens, a lens having a higher or lower optical power (diopter), or a lens having a prism correction or a cylinder correction.

[0031] In some examples, an optically enhancing deposition is applied to each of two major surfaces, where at least one of the printing surfaces is curved, and the printing of the optical enhancement includes printing, successively, respective layers on both of the two printing surfaces.

[0032] A ‘curved surface’, generally speaking, is one that is not flat, and can be concave or convex. The embodiments disclosed herein are also applicable to substrates characterized by complex shapes having both concave and convex shapes, and / or discontinuities (gradual or non-gradual changes in slope). Further, the embodiments disclosed herein are also applicable to the printing of layers to optically enhance a deposition substrate to produce an ophthalmic lens characterized in part by discontinuities or by non-horizontal planar surface shapes. The foregoing examples are not excluded from the scope of the embodiments by not being specifically described.

[0033] As used herein, the term ‘curved surface’ means a surface that is not flat and not nearly flat, where ‘nearly flat’ would describe a surface that is not strictly flat but that does not diverge from a flat, planar surface by more than a small amount, such as, by way of example, by less than 10 microns, or by less than 50 microns, or by less than 100 microns, or by less than 200 microns, or by less than 500 microns, or, additionally or alternatively, by less than the thickness of one printed layer, or two printed layers, or five printed layers. Additionally or alternatively, a nearly flat surface is one that if it were placed opposite a planar surface to form a plano-convex or plano-concave lens, the resultant optical power would be (plus or minus, respectively) no more than 0.1 diopter, or no more than 0.2 diopter, or no more 0.3 diopter, or no more than 0.4 diopter, or no more than 0.5 diopter.

[0034] A printing system provided for carrying out any of the embodiments disclosed herein comprises a control system programmed and / or programmable to take a prescription or other written or digital description of an ophthalmic lens, whether explicit or implied, e.g., by codes and / or model numbers, and translate that information to a target surface shape to be printed. The term ‘target’ as used herein relates to a digital representation, e.g., of a surface shape that is to be produced according to the embodiments. In some examples, the control system (or another computer system, whether local or remote) translates the prescription information to an ‘optical design’ as is known in the ophthalmic industry, which comprises, inter alia, a two-dimensional diopter map. In such examples, the control system translates the optical design to a three-dimensional topographic map representing the target shape of the enhanced ophthalmic lens.

[0035] Using the three-dimensional map representing the target surface shape, and information available to the control system about the shape of the printing surface of the substrate, it is possible to define a printing volume, which is the volume to be printed in order to transform the substrate into an enhanced ophthalmic lens.

[0036] The control system is further programmed or programmable to ‘slice’ the printing volume into printable layers, and this includes mapping individual pixels or voxels to individual printing layers. In some embodiments, the mapping defines a set of drop locations having ink quantity values at respective x-y coordinates. In some implementations, ink quantity values can be zero or one. In some implementations, ink quantity values can be a positive number, e.g., an integer, within a range reflecting the capabilities of an inkjet print head of the printing system to deposit any number multiple drops at a single x-y drop location. The positive number (of individual drops) can be, in illustrative, non-limiting examples, between 1 and 5, or between 1 and 7, or between 1 and 10, or between 2 and 5, or between 2 and 7, or between 2 and 10. In some implementations, the ink quantity value can be zero or a positive integer within any of the foregoing ranges.

[0037] In some implementations, the layers can be three-dimensional and non-planar such that different drop locations have different respective z-axis coordinates. The references to x-, y- and z- axis values refer to the commonly used coordinate system where x- and y-axis vectors define the horizontal plane, while the z-axis represents the vertical direction orthogonal to the horizontal plane.

[0038] The printing layers are deposited as patterns of a radiation-curable ink. In some embodiments, the ink is radiation-curable but not necessarily polymerizable; nonetheless the terms are used interchangeably in the present disclosure and in the appended claims, and both can be understood to mean radiation-polymerized or otherwise radiation-cured.

[0039] In an illustrative example, a polymeric dispersion such as an aqueous polyurethane dispersion can be radiation cured but does not undergo further polymerization.

[0040] Various methods and processes are known for polymerizing curable inks and similar compositions, e.g., by irradiating the compositions, e.g., with actinic radiation such as, and not exhaustively, UV, IR, microwave and / or visible light. In an example, a suitable polymerizable composition can be cured to 80% of a final hardness (e.g., Rockwell hardness value) within no more than 2 minutes. In some embodiments, the printing system includes a source of curing and / or polymerizing radiation.

[0041] An example of a polymerizing or curing radiation includes electromagnetic radiation in the ultraviolet spectrum, and especially in the upper end of the UV-A range, e.g., 390-400nm, or 395-405nm, or 395-400nm. In some implementations, a polymerizing wavelength or range of wavelengths depends on the formulation of the specific radiation-polymerizable composition. In some implementations, the wavelength is user- or software-selectable based on the specific composition used, and in some implementations different UV -radiati on emitters, e.g., different lamps, are used in conjunction with different compositions requiring different wavelengths.

[0042] In an example, with respect to a suitable polymerizable composition, a radiation-cured polymer can comprise a photoinitiator or a reaction product thereof.

[0043] Examples of suitable photoinitiators include, and not exhaustively: aromatic ketones and synergistic amines, alkyl benzoin ethers, thioxathones and derivatives, benzil ketals, acylphosphine oxide, ketoxime or acyl oxime esters, cationic curing quaternary ammonium salts, and acetophenone derivatives.

[0044] Examples of suitable resins acting as oligomers can include, and not exhaustively, acrylate oligomers, including epoxy acrylates, urethane acrylates and polyester acrylates.

[0045] More specific families include unsaturated poly ester / aery lated polyester, acrylated epoxy resin, acrylated aliphatic urethanes, acrylated aromatic urethanes, acrylated silicone resins, acrylated polyethers, acrylated melamines, acrylated oils, N-vinyl urethanes, and thiol-ene systems.

[0046] Examples of suitable monomers for use in UV-curing include, and not exhaustively, acrylate monomers such as linear monoacrylate, cyclic monofunctional, aromatic monofunctional, difunctional acrylate, trifunctional acrylate, tetrafunctional acrylate monomers, as well as higher functional acrylate monomers.

[0047] Additional examples of suitable monomers for use in UV-curing include, and not exhaustively: neopentyl glycol diacrylate, hexanediol diacrylate 1,6, polyethylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, dianol 2,2 diacrylate, and UV E70 polyester acrylate.

[0048] Various commercially available UV-curable, jettable varnishes may be used, including:

[0049]

[0050] Referring now to the illustrations, and in particular to Fig. 1, selected elements of a printing system for optically enhancing a deposition substrate to produce an ophthalmic lens 100 are shown. As shown the printing system 200 comprises a multiple-nozzle inkjet print head 210 for depositing drops of a curable ink 7, and an optional source 250 of curing radiation. A deposition substrate 38 is shown in cross-section as having deposited thereupon an optically enhancing deposition 75 comprising a plurality of deposited printing layers (shown in Fig. 4A). The optically enhancing deposition 75 is bounded from above by an upper surface 83 based on the target shape used to define the printing volume as described above. The optically enhancing deposition 75 is shown as deposited on a first major surface 81 of the deposition substrate 38, which, in the non-limiting example of Fig. 1, has a concave surface. In another non-limiting example illustrated in Fig. 2, the first major surface 81 of the deposition substrate 38 - the one to printed upon -is convex, and the second major surface 82 is concave. In some embodiments, both major surfaces 81, 82 can have optically enhancing depositions printed thereupon.

[0051] Both Figs. 1 and 2 schematically illustrate, again in cross section, the outline of an eyeglass lens that is the object of the printing. The eyeglass lens has a dimension 800. e.g., length, width or diagonal, which is less than a corresponding dimension of the deposition substrate 38 such that not all of the substrate is part of the final eyeglass lens. As can be seen, it is not necessary to print the layers on the entire surface 81 of the deposition substrate 38, since the rest of the deposition substrate 38 is later removed to finish the lens, and some material cost and printing time can be saved. On the other hand, there may be commercial, operational or logistical considerations indicating the printing of layers that are larger than the outline of the eyeglass lens.

[0052] Fig. 3 schematically illustrates, in isolation, the optically enhancing deposition 75 of Fig. 1. The upper surface 83 of the optically enhancing deposition 75 matches or emulates the target surface shape of the optical design (emulates, i.e., to the extent that the printing process succeeded in matching the optical design). The lower surface of the optically enhancing deposition 75 has a shape given it by the first major surface 81 of the deposition substrate 38.

[0053] We now refer to Figs. 4 and 5. Fig. 4A shows the optically enhanced ophthalmic lens 100 of Fig. 1 according to embodiments, with the optically enhancing deposition 75 shown as a plurality of n printed layers 35 deposited in accordance with the layers created by division of the printing volume by the control system. The number of layers 35 shown in Fig. 4A is merely for purposes of illustration, and in practice the number of layers 35 can be higher, e.g., more than 20, more than 30, more than 40, or more than 50, depending, inter alia on the thickness of the printing volume, the size of the deposited drops of curable ink and its viscosity. An individual layer can be in the thickness range of 1.5-25 microns, and more typically, 1.5-15 microns or 1.5-10 microns.

[0054] In embodiments, after each layer is deposited by the inkjet printing head 210, it can be at least partially cured by the source 250 of curing radiation, which can include any suitable radiation emitter in accordance with material-specific and process-specific requirements for curing the a given curable ink 7. In some embodiments, the at least partial curing takes place after a given number of layers 35, e.g., every 5-10 layers, depending in part on drop volume, viscosity and substrate shape, and / or a given accumulated thickness since the previous partial curing, e.g., every 20-50 microns, or as little as every 10 microns for a less viscous curable ink 7. In examples, the partial curing can take 1-5 seconds, or 1-3 seconds.

[0055] In embodiments, the order in which the layers 35 are deposited can be different from the original order in which the printing layers are created by the control system when dividing the printing volume into layers. The layers can be manipulated so as to improve optical quality of the ophthalmic lens 100, and / or to improve one or more optical properties of the ophthalmic lens 100.

[0056] The term ‘optical quality’ is used herein to mean an attribute, e.g., of an ophthalmic lens, that contributes to, or detracts from, the production quality of the lens. Examples of such attributes can include, but not exhaustively: transparency, e.g., in terms of transmissivity in the visible spectrum; clarity, e.g., in terms of constancy of refraction index; refraction and scattering, e.g., due to the presence of opaque material of embedded particles or surface roughness; material-related defects including rheologic parameters and polymerization kinetics; and visible artifacts of a discrete printing process including steps between layer edges and evidence of inter-drop spacing. The somewhat similar term ‘optical properties’ as used herein refers to ophthalmological characteristics such as diopter, cylinder, prism, and the like. ‘Improving’ an optical property means improving the accuracy with which an ophthalmological characteristic is reproduced in the dropdeposition process described herein. It is now disclosed that an improvement of one or more optical properties can be achieved by controlling the deposition order of layers, by modifying a distribution of drop locations within a layer, and by manipulating drop-layer assignments - all of which are elements of a slicing / printing policy. In some embodiments, an improvement in optical quality or in an optical property can be based on an optimization of one or more slicing / printing policy elements.

[0057] In the non-limiting example of Fig. 4B, the printing order of the layers 35 is different than the order of the ‘vertical’ stack of printing layers created by the control system when dividing the printing volume into printing layers - that order being shown in Fig. 4A - and in fact, the order is reversed. Reversing the order means that, for example, if the original order of the n layers was from 351 to 35„, the reversed order would be from 35„ to 35i.

[0058] In embodiments, printing layers can be modified by ‘moving’ ink quantities from one layer to another. In a first example, an entire drop location - an x-y location allotted an ink drop in the virtual layer-creation process - from one layer to a neighboring layer, or even to non-neighboring layer, as long as the destination layer also includes the given x,y pixel in question, and can accommodate the drop. In another example, part of an ink quantity value for a given x-y location is moved from a first layer to a neighboring layer or to a non-neighboring layer that also includes the given x,y pixel in question, and can accommodate the increase in ink quantity value. The removing and adding of drop locations or ink quantity values are intended to increase the optical quality of the ophthalmic lens, and / or to improve one or more optical properties of the ophthalmic lens.

[0059] Fig. 5 schematically shows two non-limiting examples of moving ink from a first layer to a second layer, either as entire drop locations or as partial ink quantity values according to embodiments. The arrow marked ‘A’ indicates virtual movement of ink from a location at (x,y)i on layer 35i to the same x,y location on neighboring layer 352.

[0060] The arrow marked ‘B’ indicates virtual movement of ink from a location at (x,y)2 on layer 35„ to the same (x,y)2 location on layer 35„+3.

[0061] In some embodiments, modifying the printing layers as sliced from the printing volume can includes determining at least one of a total z-height and a total ink quantity value across all of the printing layers for the given pair of x-y coordinates. The assignment, or re-assignment, of drop locations and ink quantity values to the various layers can be modified in terms of the printing order of all the ink drops (across all layers) at the given pair of x-y coordinates in an optimization step, based on improving the optical quality of the ophthalmic lens and / or an optical property of the ophthalmic lens, a printing order of drops of the curable ink for drop locations at the given pair of x-y coordinates.

[0062] We now refer to Figs. 6, 7 and 8. Fig. 6 shows three schematic illustrations of printing layers as created by the control system when dividing the printing volume into printing layers according to embodiments. The layers are shown as being round only for purposes of convenience of illustration, and can be any shape including, without limitation, the shape of an eyeglass lens. Each of the three illustrations in Fig. 6 shows a two-dimensional projection of a layer 35 divided into a first portion 91 in which the drop locations are arranged in accordance with an ordered distribution and a second portion 92 in which the drop locations are arranged in accordance with a stochastic distribution. A stochastic distribution is one where ink quantity values (zero drops or a positive-integer number of drops) for any given drop location are selected based on a probability distribution function. In non-limiting examples, the stochastic distribution can be characterized by blue noise, white noise, red noise, green noise, or an error-function distribution. In contrast, an ‘ordered distribution’ is not a probabilistic distribution but instead uses a straightforward translation of a portion of the printing layer into ink quantity values for respective drop locations on an x-y grid that is determined by a selected printing frequency and row spacing, without intra-layer manipulation.

[0063] Unlike the application of printing techniques in so-called ‘graphic’ printing in which images are digitized and optimized for printing, the manipulation of drop locations and ink quantity values in the embodiments disclosed herein is unrelated to the art of printing images, and instead is geared towards improving the optical quality of the ophthalmic lens and / or an optical property of the entire ophthalmic lens - and not of an individual layer.

[0064] The first portion 91 based on the ordered distribution may be printed naively without special steps being taken to improve or maintain optical quality. Nonetheless, the ratio of the first portion 91 to the second portion 92 in any given layer, by area and / or by ink quantity is selectable to increase or maintain optical quality of the ophthalmic lens, and / or to improve one or more optical properties of the ophthalmic lens. Moreover, the second portion 92 based on the stochastic distribution can be manipulated to improve or maintain optical quality. For example, the absolute depth of the second portion 92 in any given layer is selectable to increase or maintain optical quality of the ophthalmic lens, and / or to improve one or more optical properties of the ophthalmic lens. The term ‘depth’ in this context means the number of pixels in from a perimeter of the layer. As can been seen in Fig. 6, layer ‘A’ has the highest area ratio of first portion 91 to second portion 92 of the three illustrated layers, and also the greatest second-portion 92 depth of the three. Layer ‘B’ has a lower ratio and a lower depth than ‘A’, while layer ‘C’ has a lower ratio and depth than either.

[0065] In embodiments, the specific stochastic distribution of the second portion 92 can be selected to increase or maintain optical quality of the ophthalmic lens, and / or to improve one or more optical properties of the ophthalmic lens.

[0066] As can be seen in Fig. 6, the second portion 92 can include the perimeter of a layer. In some embodiments, the second portion 92 includes at least part of the perimeter, but it can be advantageous to have the ability to manipulate parameters of the stochastic distribution specification at and near the entire perimeter in order to contribute to the optimization of optical quality. In some embodiments, the depth (from the perimeter) included in the second portion 92 includes, for each drop location on or nearest the perimeter, at least the 10 closest drop locations (or pixels or voxels) within the perimeter, or at least the 20 closest drop locations, or at least the 30 closest drop locations, or more.

[0067] In some embodiments, a number of drop locations are located outside the perimeter. The inventor have found that this ‘painting outside the numbers’ approach can be employed improve the optical quality of the ophthalmic lens, e.g., by way of smoothing the outer contour of the printed lens enhancement. Fig. 7 shows an illustrative use case using layers ‘B’ and ‘C’ of Fig. 6. Layer ‘B’ is shown with a perimeter 95, and thus it can be seen that the ‘stochastic’ area of the layer extends beyond the perimeter. Although the representation of the layers in Fig. 6 does not indicate the probability density of the distribution function within the second portion 92, the density can be controlled in order to increase or maintain optical quality of the ophthalmic lens, and / or to improve one or more optical properties of the ophthalmic lens. In embodiments, the density in that part of the second portion 92 located within the perimeter is higher than the density of the part beyond the perimeter. In a non-limiting example, the stochastic function yields a density (i.e., probability of a positive ink quantity value at a given drop location) of between 0.5 and 1 at any drop location within the perimeter, and a density of between 0 and 0.5 at any drop location outside the perimeter. In other examples, other ranges are used, including overlapping ranges that further ‘blur’ the perimeter probabilistically. In some embodiments, there can be more than two probability ranges for the second portion 92.

[0068] An exemplary object of ‘painting outside the numbers’ is to smooth the transition, within the contour, from one layer to the next, and therefore it can be desirable that the drop locations located beyond the respective perimeter 95 are at x-y coordinates contained in an adjacent printing layer. Still referring to Fig. 7, the illustration of layer ‘C’ has superimposed over it the perimeter 95 of layer ‘B’, along with an ‘effective perimeter’ 96, i.e., the greatest extent of drop locations of layer ‘B’, including those outside the nominal perimeter 95. The ‘effective’ perimeter 96 of layer ‘B’ is also superimposed over layer ‘C’ in Fig. 7. All of the (x,y) coordinates of the drop locations of layer ‘B’ are indeed contained in the footprint of layer ‘C’, which according to an example is adjacent to layer ‘B’, i.e., immediately before or after, in a printing order. In embodiments, a physical ‘step’ is the extent, in a two-dimensional projection, of the difference of the footprint, or (x,y) coordinate map, between two adjacent layers where ‘adjacent’ means immediately before or after, in a printing order.

[0069] In some embodiments, the effective perimeter is regulated to reduce the apparent size of a physical step, e.g., by extending the effective perimeter of the smaller of the two adjacent layers to cover a selectable fraction of what would be the step, and / or by adjusting a selectable probability density in the part of the second portion 92 of the smaller of the two adjacent layers that is beyond its respective perimeter 95. In embodiments, reducing the apparent size can be effective order to increase or maintain optical quality of the enhanced ophthalmic lens 100.

[0070] Fig. 8 is a schematic illustration of layers ‘B’ and ‘C’ from Fig. 6, in terms of assigned drop locations rather than the division into distribution portions 91, 92. As can be seen, beyond respective perimeters 95, 96, the densities of the respective probability functions decrease.

[0071] Fig. 9 is a block diagram of a printing system 200 for optically enhancing a deposition substrate to produce an ophthalmic lens according to embodiments. The elements shown in solid-line boxes, substrate receptable 225, inkjet printing head 210 and control system 50, are always part of a system 200. The substrate receptable 225 for receiving a deposition substrate 38 is configured to support the substrate 38 and optionally secure it. The inkjet printing head 210, as shown in Fig. 1, comprises multiple ink-ejection nozzles, preferably arranged co-planarly. Details of an exemplary control system 50 are shown in the block diagram of Fig. 10. As shown in the block diagram of Fig. 10, an exemplary control system 50 comprises computing equipment and ancillary equipment configured for monitoring, controlling, regulating and / or actuating one or more components or sub-systems of the printing system 200. Depending on location and customization, the control system can include any or all of (and not exhaustively): one or more computer processors 55, computer-readable storage media 58, 59, and a communications module 57. The computer-readable program storage media 58, 59 can include transient and / or transient storage, and can include one or more storage units, all in accordance with desired functionality and design choices. Some or all of the computer-readable program storage media 58, 59 can be cloud-based. In embodiments, the program storage 58 can be used for storing program instructions in firmware and / or software, for execution by the one or more processors 55; operating data and / or maintenance data relating to components of the printing system 200 and / or produced ophthalmic lenses 100 can be stored in the data storage module 59. The communications module 57 can be configured to establish communications links with external computers, e.g., for software and firmware updates, database access, etc., and to interact with users through a user interface (not shown). In some embodiments, not all of the illustrated components of the control system 50 are provided.

[0072] Referring again to Fig. 9, elements shown in dashed-line boxes, which are not required to be part of the printing system 200 in every implementation and configuration. These include:

[0073] A source 250 of curing radiation, e.g., an emitter of actinic radiation. A single-nozzle ink source 280, e.g., a micro-jetting device for aspects of lens production, including without limitation coatings, that do not require drops as small as those available from an inkjet printing head 210.

[0074] An energy treatment apparatus 285, e.g., for applying an energy treatment to raise the surface energy of the first major surface 81 of the deposition substrate 38. Examples of suitable energy treatments can include, and not exhaustively: a corona treatment, a plasma treatment, an electron beam treatment, an electromagnetic (e.g., actinic) radiation treatment, and an electrical discharge treatment.

[0075] A coater such as, for example, a spin coater or dip coater, for applying a coating to either or both of the two major surfaces 81, 82 of the deposition substrate 38 at any time before and / or after the deposition of the printing layers 35. Examples of suitable coatings can include, and not exhaustively: a protective coating such as a hard coat, a tintable hard coat, and a tinted hard coat, and a functional coating such as a photochromic coating, a tint coating, a thermochromic coating, a UV-blocking coating, and a blue-light blocking coating. In some embodiments, one or more of the coatings is applied by the inkjet printing head 210.

[0076] The skilled artisan will understand that the printing system 200 may additionally include any number of additional elements necessary for carrying out the embodiments but not shown in Fig. 9, including, and not exhaustively, housings, electrical systems and equipment, internal and external material supply and transport systems and equipment, cleaning stations and equipment, and quality control stations and equipment.

[0077] Referring now to Fig. 11, a method is disclosed for optically enhancing a deposition substrate 38 to produce an ophthalmic lens 100. As illustrated by the flow chart in Fig. 11, the method comprises at least the four steps SOI, S02, S03 and S04.

[0078] Step SOI includes: receiving the deposition substrate 38, the deposition substrate 38 comprising a first major surface 81 having a non-planar shape.

[0079] Step S02 includes: defining a printing volume bounded by a target surface shape and the non-planar shape of the first major surface 81.

[0080] Step S03 includes: dividing the printing volume into a set of vertically ordered printing layers, each printing layer defining a set of drop locations having respective x-y coordinates, the dividing being such that for respective drop locations of some printing layers, or of a majority of the printing layers, or of all of the printing layers, a first portion 91 of the drop locations is arranged in an ordered distribution and a second portion 92 of the drop locations is arranged in a stochastic distribution. In some embodiments, the dividing includes selecting a ratio, by area and / or by ink quantity, of the first portion 91 of a printing layer to the second portion 92, so as to increase optical quality of the ophthalmic lens 100, and / or to improve one or more optical properties thereof. Step S04 includes: sequentially depositing the printing layers 35, by an inkjet printing head 210, onto the first major surface 81 so as to form the target surface shape 83, the deposited printing layers 35 comprising drops of a curable ink 7.

[0081] In some embodiments, for any printing layer 35 characterized by having both the first and second portions 91, 92, the second portion 92 includes at least part of, or all of, a perimeter 95 of the layer 35, and for any drop location at or adjacent to the perimeter 95, the second portion 92 includes at least the 10 closest drop locations within the perimeter 95, or at least the 20 closest drop locations. In some embodiments, a plurality of drop locations of a printing layer 35 characterized by having both the first and second portions 91, 92 are located outside a respective perimeter 95 of the layer, a majority of said drop locations being characterized by zero ink quantity values. The drop locations located beyond the respective perimeter 95 are at x-y coordinates contained in an adjacent printing layer 35. In some embodiments, each of the drop locations of at least the second portion 92 is characterized by an ink quantity value selected from a range of values comprising a zero value and a plurality of positive values, and the value is selected to increase optical quality of the ophthalmic lens 100, and / or to improve one or more optical properties thereof. In some embodiments, not all of the steps of the method are carried out.

[0082] Referring now to Fig. 12, a method is disclosed for optically enhancing a deposition substrate 38 to produce an ophthalmic lens 100. As illustrated by the flow chart in Fig. 12, the method comprises at least the four steps Sil, S12, S13 and S14.

[0083] Step Sil includes: receiving the deposition substrate 38, the deposition substrate 38 comprising a first major surface 81 having a non-planar shape.

[0084] Step S12 includes: defining a printing volume bounded by a target surface shape and the non-planar shape of the first major surface 81.

[0085] Step S13 includes: dividing the printing volume into a set of vertically ordered printing layers, each printing layer defining a set of drop locations having respective x-y coordinates.

[0086] Step S14 includes: modifying at least two of the printing layers 35 in at least one of the two following ways: (A) for a given pair of x-y coordinates, a defined drop location is removed from a first printing layer 35 and added to a second printing layer 35, and (B) for a given pair of x-y coordinates, an ink quantity value of a defined drop location is reduced from a first printing layer 35 and correspondingly increased in a second printing layer 35.

[0087] In some embodiments, the modifying of Step S14 includes the modifying includes (i) determining at least one of a total z-height and a total ink quantity value across all of the printing layers for the given pair of x-y coordinates, and (ii) optimizing, based on at least one of optical quality of the ophthalmic lens, and an optical property thereof, a printing order of drops of the curable ink for drop locations at the given pair of x-y coordinates.

[0088] Step S15 includes causing an inkjet printing head 210 to sequentially deposit the modified printing layers 35 onto the first major surface 81.

[0089] In some embodiments, not all of the steps of the method are carried out.

[0090] The scope of the present disclosure includes, without limitation, the following exemplary inventive concepts:

[0091] Inventive concept 1. A printing system for optically enhancing a deposition substrate to produce an ophthalmic lens, the system comprising: (a) a deposition-substrate receptacle; (b) an inkjet printing head operable, in a first operating mode in which a deposition substrate has been received in or upon the deposition-substrate receptacle, to deposit drops of a curable ink onto a first major surface of the deposition substrate; and (c) a computerized control system configured to regulate operation of the inkjet printing head, wherein the control system is programmed or programmable to carry out the following steps: (i) defining a printing volume bounded by a target surface shape and a non-planar shape of the first major surface, (ii) dividing the printing volume into a set of vertically ordered printing layers, each printing layer defining a set of drop locations having ink quantity values at respective x-y coordinates, and (iii) when in the first operating mode, causing the inkjet printing head to sequentially deposit the printing layers onto the first major surface of the deposition substrate to form the target surface shape, the deposited printing layers comprising drops of the curable ink, the dividing being such that for respective drop locations of at least some printing layers, a first portion of the drop locations is arranged in an ordered distribution and a second portion of the drop locations is arranged in a stochastic distribution.

[0092] Inventive concept 2. The printing system of Inventive Concept 1, wherein the dividing includes selecting a ratio, by area and / or by ink quantity, of the first portion of any layer of the at least some printing layers to the second portion thereof, so as to increase optical quality of the ophthalmic lens and / or to improve one or more optical properties thereof.

[0093] Inventive concept 3. The printing system of either one of Inventive Concepts 1 or 2, wherein the second portion of any layer of the at least some printing layers includes part of, or all of, a perimeter of said printing layer.

[0094] Inventive concept 4. The printing system of any one of Inventive Concepts 1 to 3, wherein the second portion includes at least 10% of the drop locations of the least some printing layers.

[0095] Inventive concept 5. The printing system of any one of Inventive Concepts 1 to 4, wherein the second portion includes at least 30% of the drop locations of the least some printing layers.

[0096] Inventive concept 6. The printing system of any one of Inventive Concepts 1 to 5, wherein the second portion includes at least 50% of the drop locations of one or more layers of the least some printing layers.

[0097] Inventive concept 7. The printing system of any one of Inventive Concepts 1 to 6, wherein the second portion includes at least 70% of the drop locations of one or more layers of the least some printing layers.

[0098] Inventive concept 8. The printing system of any one of Inventive Concepts 1 to 7, wherein the second portion includes at least 80% of the drop locations of one or more layers of the least some printing layers.

[0099] Inventive concept 9. The printing system of any one of Inventive Concepts 1 to 8, wherein a plurality of drop locations of any layer of the at least some printing layers are located outside a respective perimeter of said printing layer, a majority of said drop locations located outside the respective perimeter being characterized by zero ink quantity values.

[0100] Inventive concept 10. The printing system of Inventive Concept 9, wherein the drop locations located outside the respective perimeter are at x-y coordinates contained in one or more other printing layers of the set of vertically ordered printing layers.

[0101] Inventive concept 11. The printing system of either one of Inventive Concepts 9 or 10, wherein the drop locations located outside the respective perimeter are at x-y coordinates contained in one or more other printing layers of the at least some printing layers.

[0102] Inventive concept 12. The printing system of any one of Inventive Concepts 9 to 11, wherein the drop locations located outside the respective perimeter are at x-y coordinates contained in an adjacent printing layer.

[0103] Inventive concept 13. The printing system of any one of Inventive Concepts 1 to 12, wherein each of the drop locations of at least the second portion is characterized by an ink quantity value selected from a range of values comprising a zero value and a plurality of positive values, wherein the value is selected to increase optical quality of the ophthalmic lens, and / or to improve one or more optical properties thereof.

[0104] Inventive concept 14. A method of optically enhancing a deposition substrate to produce an ophthalmic lens ing the printing system of any one of Inventive Concepts I to 13, the method comprising: (a) receiving the deposition substrate; (b) defining the printing volume; (c) dividing the printing volume into the set of vertically ordered printing layers, the dividing being such that for respective drop locations of at least some printing layers, a first portion of the drop locations is arranged in an ordered distribution and a second portion of the drop locations is arranged in a stochastic distribution; and (d) using drops of the curable ink, sequentially depositing the printing layers onto the first major surface of the deposition substrate so as to form the target surface shape.

[0105] Inventive concept 15. A method of optically enhancing a deposition substrate to produce an ophthalmic lens, the method comprising: (a) receiving the deposition substrate, the deposition substrate comprising a first major surface having a non-planar shape; (b) defining a printing volume bounded by a target surface shape and the non-planar shape of the first major surface; (c) dividing the printing volume into a set of vertically ordered printing layers, each printing layer defining a set of drop locations having respective x-y coordinates; and (d) causing an inkjet printing head to sequentially deposit the printing layers onto the first major surface so as to form the target surface shape, the deposited printing layers comprising drops of a curable ink, the dividing being such that for respective drop locations of some printing layers, or of a majority of the printing layers, or of all of the printing layers, a first portion of the drop locations is arranged in an ordered distribution and a second portion of the drop locations is arranged in a stochastic distribution, the defining, dividing and causing being carried out by a programmed or programmable control system.

[0106] Inventive concept 16. The method of Inventive Concept 15, wherein the dividing includes selecting a ratio, by area and / or by ink quantity, of the first portion of a printing layer to the second portion thereof, so as to increase optical quality of the ophthalmic lens, and / or to improve one or more optical properties thereof.

[0107] Inventive concept 17. The method of either one of Inventive Concepts 15 or 16, wherein for any printing layer characterized by having both the first and second portions, the second portion includes at least part of, or all of, a perimeter of the layer.

[0108] Inventive concept 18. The method of any one of Inventive Concepts 15 to 17, wherein the second portion includes at least 10% of the drop locations of the least some printing layers.

[0109] Inventive concept 19. The method of any one of Inventive Concepts 15 to 18, wherein the second portion includes at least 30% of the drop locations of the least some printing layers.

[0110] Inventive concept 20. The method of any one of Inventive Concepts 15 to 19, wherein the second portion includes at least 50% of the drop locations of one or more layers of the least some printing layers.

[0111] Inventive concept 21. The method of any one of Inventive Concepts 15 to 20, wherein the second portion includes at least 70% of the drop locations of one or more layers of the least some printing layers.

[0112] Inventive concept 22. The method of any one of Inventive Concepts 15 to 21, wherein the second portion includes at least 80% of the drop locations of one or more layers of the least some printing layers.

[0113] Inventive concept 23. The method of any one of Inventive Concepts 15 to 22, wherein a plurality of drop locations of any layer of the at least some printing layers are located outside a respective perimeter of said printing layer, a majority of said drop locations located outside the respective perimeter being characterized by zero ink quantity values.

[0114] Inventive concept 24. The method of Inventive Concept 23, wherein the drop locations located outside the respective perimeter are at x-y coordinates contained in one or more other printing layers of the set of vertically ordered printing layers. Inventive concept 25. The method of either one of Inventive Concepts 23 or 24, wherein the drop locations located outside the respective perimeter are at x-y coordinates contained in one or more other printing layers of the at least some printing layers.

[0115] Inventive concept 26. The method of any one of Inventive Concepts 23 to 25, wherein the drop locations located beyond a respective perimeter are at x-y coordinates contained in an adjacent printing layer.

[0116] Inventive concept 27. The method of any one of Inventive Concepts 15 to 26, wherein each of the drop locations of at least the second portion is characterized by an ink quantity value selected from a range of values comprising a zero value and a plurality of positive values, wherein the value is selected to increase optical quality of the ophthalmic lens, and / or to improve one or more optical properties thereof.

[0117] Inventive concept 28. A printing system for optically enhancing a deposition substrate to produce an ophthalmic lens, the system comprising: (a) a deposition-substrate receptacle; (b) an inkjet printing head operable, in a first operating mode in which the deposition substrate has been received in or upon the deposition-substrate receptacle, to deposit drops of a curable ink onto a first major surface of deposition substrate; and (c) a computerized control system configured to regulate operation of the inkjet printing head, wherein the control system is programmed or programmable to carry out the following steps: (i) defining a printing volume bounded by a target surface shape and a non-planar shape of the first major surface, (ii) dividing the printing volume into a set of vertically ordered printing layers, each printing layer defining a set of drop locations having respective x-y coordinates, (iii) modifying at least two of the printing layers in at least one of the two following ways: (A) for a given pair of x-y coordinates, a defined drop location is removed from a first printing layer and added to a second printing layer, and (B) for a given pair of x-y coordinates, an ink quantity value of a defined drop location is reduced from a first printing layer and correspondingly increased in a second printing layer, and (iv) when in the first operating mode, causing the inkjet printing head to deposit the modified printing layers onto the first major surface of the deposition, the deposited modified printing layers comprising drops of the curable ink.

[0118] Inventive concept 29. The printing system of Inventive Concept 28, wherein the modifying includes (i) determining at least one of a total z-height and a total ink quantity value across all of the printing layers for the given pair of x-y coordinates, and (ii) optimizing, based on at least one of optical quality of the ophthalmic lens, and an optical property thereof, a printing order of drops of the curable ink for drop locations at the given pair of x-y coordinates.

[0119] Inventive concept 29 A. The printing system of any one of Inventive Concepts 1 to 12 or 28 to 29, wherein the deposition-substrate receptacle is dimensioned and adapted to receive an eyeglass lens or lens blank.

[0120] Inventive concept 29B. The printing system of any one of Inventive Concepts 1 to 12 or 28 to 29A, the system further including the deposition substrate.

[0121] Inventive concept 29C. The printing system of Inventive Concept 29B, wherein the deposition substrate is an or the eyeglass lens or lens blank.

[0122] Inventive concept 29D. The printing system of any one of Inventive Concepts 1 to 12 or 28 to 29C, wherein the first major surface is a curved surface.

[0123] Inventive concept 30. A method of optically enhancing a deposition substrate to produce an ophthalmic lens using the printing system of any one of Inventive Concepts 28 to 29D, the method comprising: (a) receiving the deposition substrate; (b) defining the printing volume; (c) dividing the printing volume into the set of vertically ordered printing layers; (d) modifying the at least two of the printing layers; and (e) using drops of the curable ink, sequentially depositing the printing layers onto the first major surface of the deposition substrate so as to form the target surface shape.

[0124] Inventive concept 31. The method of Inventive Concept 30, wherein the modifying includes (i) determining at least one of a total z-height and a total ink quantity value across all of the printing layers for the given pair of x-y coordinates, and (ii) optimizing, based on at least one of optical quality of the ophthalmic lens, and an optical property thereof, a printing order of drops of the curable ink for drop locations at the given pair of x-y coordinates.

[0125] Inventive concept 32. A method of optically enhancing a deposition substrate to produce an ophthalmic lens to produce an ophthalmic lens, the method comprising: (a) receiving the deposition substrate, the deposition substrate comprising a first major surface having a non-planar shape; (b) defining a printing volume bounded by a target surface shape and the non-planar shape of the first major surface; (c) dividing the printing volume into a set of vertically ordered printing layers, each printing layer defining a set of drop locations having respective x-y coordinates; (d) modifying at least two of the printing layers in at least one of the two following ways: (A) for a given pair of x-y coordinates, a defined drop location is removed from a first printing layer and added to a second printing layer, and (B) for a given pair of x-y coordinates, an ink quantity value of a defined drop location is reduced from a first printing layer and correspondingly increased in a second printing layer; and (e) causing an inkjet printing head to sequentially deposit the printing layers onto the first major surface so as to form the target surface shape, the deposited printing layers comprising drops of a curable ink, the defining, dividing, modifying and causing being carried out by a programmed or programmable control system.

[0126] Inventive concept 33. The method of Inventive Concept 31, wherein the modifying includes (i) determining at least one of a total z-height and a total ink quantity value across all of the printing layers for the given pair of x-y coordinates, and (ii) optimizing, based on at least one of optical quality of the ophthalmic lens, and an optical property thereof, a printing order of drops of the curable ink for drop locations at the given pair of x-y coordinates.

[0127] The present invention has been described using detailed descriptions of embodiments thereof that are provided by way of example and are not intended to limit the scope of the invention. The described embodiments comprise different features, not all of which are required in all embodiments of the invention. Some embodiments of the present invention utilize only some of the features or possible combinations of the features. Variations of embodiments of the present invention that are described and embodiments of the present invention comprising different combinations of features noted in the described embodiments will occur to persons skilled in the art to which the invention pertains.

Claims

WHAT IS CLAIMED IS:

1. A printing system for optically enhancing a deposition substrate to produce an ophthalmic lens, the system comprising:a. a deposition-substrate receptacle;b. an inkjet printing head operable, in a first operating mode in which a deposition substrate has been received in or upon the deposition-substrate receptacle, to deposit drops of a curable ink onto a first major surface of the deposition substrate; andc. a computerized control system configured to regulate operation of the inkjet printing head,wherein the control system is programmed or programmable to carry out the following steps:i. defining a printing volume bounded by a target surface shape and a non-planar shape of the first major surface, ii. dividing the printing volume into a set of vertically ordered printing layers, each printing layer defining a set of drop locations having ink quantity values at respective x-y coordinates, and iii. when in the first operating mode, causing the inkjet printing head to sequentially deposit the printing layers onto the first major surface of the deposition substrate to form the target surface shape, the deposited printing layers comprising drops of the curable ink, the dividing being such that for respective drop locations of at least some printing layers, a first portion of the drop locations is arranged in an ordered distribution and a second portion of the drop locations is arranged in a stochastic distribution.

2. The printing system of claim 1, wherein the dividing includes selecting a ratio, by area and / or by ink quantity, of the first portion of any layer of the at least some printing layers to the second portion thereof, so as to increase optical quality of the ophthalmic lens and / or to improve one or more optical properties thereof.

3. The printing system of either one of claims 1 or 2, wherein the second portion of any layer of the at least some printing layers includes part of, or all of, a perimeter of said printing layer.

4. The printing system of any one of claims 1 to 3, wherein the second portion includes at least 30% of the drop locations of the least some printing layers.

5. The printing system of any one of claims 1 to 4, wherein the second portion includes at least 50% of the drop locations of one or more layers of the least some printing layers.

6. The printing system of any one of claims 1 to 5, wherein a plurality of drop locations of any layer of the at least some printing layers are located outside a respective perimeter of said printing layer, a majority of said drop locations located outside the respective perimeter being characterized by zero ink quantity values.

7. The printing system of claim 6, wherein the drop locations located outside the respective perimeter are at x-y coordinates contained in one or more other printing layers of the set of vertically ordered printing layers.

8. The printing system of either one of claims 6 or 7, wherein the drop locations located outside the respective perimeter are at x-y coordinates contained in an adjacent printing layer.

9. A method of optically enhancing a deposition substrate to produce an ophthalmic lens using the printing system of any one of claims 1 to 8, the method comprising:a. receiving the deposition substrate;b. defining the printing volume;c. dividing the printing volume into the set of vertically ordered printing layers, the dividing being such that for respective drop locations of at least some printing layers, a first portion of the drop locations is arranged in an ordered distribution and a second portion of the drop locations is arranged in a stochastic distribution; andd. using drops of the curable ink, sequentially depositing the printing layers onto the first major surface of the deposition substrate so as to form the target surface shape.

10. A method of optically enhancing a deposition substrate to produce an ophthalmic lens, the method comprising:a. receiving the deposition substrate, the deposition substrate comprising a first major surface having anon-planar shape;b. defining a printing volume bounded by a target surface shape and the non- planar shape of the first major surface;c. dividing the printing volume into a set of vertically ordered printing layers, each printing layer defining a set of drop locations having respective x-y coordinates; andd. causing an inkjet printing head to sequentially deposit the printing layers onto the first major surface so as to form the target surface shape, the deposited printing layers comprising drops of a curable ink,the dividing being such that for respective drop locations of some printing layers, or of a majority of the printing layers, or of all of the printing layers, a first portion of the drop locations is arranged in an ordered distribution and a second portion of the drop locations is arranged in a stochastic distribution, the defining, dividing and causing being carried out by a programmed or programmable control system.

11. The method of claim 10, wherein the dividing includes selecting a ratio, by area and / or by ink quantity, of the first portion of a printing layer to the second portion thereof, so as to increase optical quality of the ophthalmic lens, and / or to improve one or more optical properties thereof.

12. The method of either one of claims 10 or 11, wherein for any printing layer characterized by having both the first and second portions, the second portion includes at least part of, or all of, a perimeter of the layer.

13. The method of any one of claims 10 to 12, wherein the second portion includes at least 50% of the drop locations of one or more layers of the least some printing layers.

14. The method of any one of claims 10 to 13, wherein a plurality of drop locations of any layer of the at least some printing layers are located outside a respective perimeter of said printing layer, a majority of said drop locations located outside the respective perimeter being characterized by zero ink quantity values.

15. The method of claim 14, wherein the drop locations located outside the respective perimeter are at x-y coordinates contained in one or more other printing layers of the at least some printing layers.

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