Methods and compositions for tinting ophthalmic lens substrates

Abstract

The present invention relates to a method and composition for tinting an eyeglass lens substrate. A method (100) for in-substrate tinting of an eyeglass lens substrate (1), the method (100) comprising the following steps: S1: providing an eyeglass lens substrate (1) comprising a polymer lens material (2), S2: providing a composition (3) comprising a polymer carrier material (4), S3: applying a pattern (5) of the composition (3) on a surface (6) of the eyeglass lens substrate (1), and S4: heating the eyeglass lens substrate (1) to diffuse a dye substance (7) between the carrier material (4) and the lens material (2), wherein the lens material (2) comprises a dye substance (7) and the dye substance (7) is transferred from the lens material (2) to the carrier material (4) by diffusion.

Description

[0001] This application is a divisional application of a patent application with an application date of September 6, 2022, an application number of 202280057760.9, an international application number of PCT / EP2022 / 074717, and an invention name of “Methods and compositions for coloring eyeglass lens substrates”. Technical Field

[0002] The present invention relates to a method for tinting an ophthalmic lens substrate, a composition for tinting a polymer ophthalmic lens substrate and an ophthalmic lens substrate comprising a polymer lens material. Background Art

[0003] Ophthalmic lenses are tinted and / or marked for a variety of reasons. For example, temporary marks on the lens surface can be used to achieve alignment and alignment control of the finished ophthalmic lens for subsequent processing steps such as cutting or perforating. Due to the hydrophobic and / or oleophobic properties of the surface caused by the surface material itself or a coating applied to the surface, simple surface printing generally cannot produce marks of the required quality, especially marks with the desired resolution and durability.

[0004] US 9709819 B2 discloses a method for printing temporary inkjet marks or patterns on surfaces, in particular hydrophobic surfaces, which have good mechanical retention on the substrate surface and avoid the problem of ink droplet coalescence. The method comprises at least two ink printing steps. The first step deposits a first ink layer and comprises ejecting ink drops at a sufficient speed to flatten them on the surface to be printed, thereby increasing the adhesion of the ink. The second step comprises ejecting ink droplets, which are generally larger in size than the ink droplets of the first layer, at an ejection speed that is generally lower than the ejection speed during the first step. Due to the fact that the ink droplets are deposited on a sublayer of known solidified ink formed by the solidified ink droplets of the first layer, the adhesion and behavior of the ink droplets of the second layer formed by the second step are independent of the surface treatment and surface material of the substrate (e.g., ophthalmic lens).

[0005] However, the disclosed method is time consuming due to the two-step procedure and can only be used for temporary marking since the deposited ink drops are only located on the surface.

[0006] In addition to temporary marking, the tinting (sometimes called coloring) of ophthalmic lenses is also used for various purposes, such as filtering specific wavelengths of light or aesthetic aspects. Conventionally, tinted ophthalmic lenses are prepared by immersing the substrate in a bath containing the dye in a manual linear process. However, this method exhibits disadvantages in terms of reproducibility and uniformity. In addition, it is not possible to obtain locally resolved coloring. The so-called bleaching method used to remove excess dye from a lens that is too dark usually also affects the entire lens, because the entire lens is immersed in the bleaching bath.

[0007] In order to improve the tinting of ophthalmic lenses, US 8740996 B2 discloses a transparent printing primer that can be tinted by inkjet printing. It can be used in a method for tinting an optical lens or producing a graphic representation on a lens, the method comprising depositing the primer on the surface of the optical lens, drying the primer, printing the primer using an inkjet printer, and drying the ink. JP 2000-314088 A discloses another method using an auxiliary layer applied to the surface of the lens.

[0008] WO 2006 / 079564A1, which is considered to be the closest prior art to the invention disclosed herein, describes a method for tinting an optical lens, which comprises: coating a substrate of the optical lens with a layer of an ink receptor material capable of forming a porous ink receptor film, evaporating a solvent present in the ink receptor material to form a porous film, applying an ink solution to the porous film using an inkjet machine so that the ink solution is absorbed into the film, heating the optical lens until the substrate has obtained the desired tinting and removing the ink receptor film.

[0009] However, a disadvantage of these methods is the need for auxiliary layers and the additional method steps associated therewith.

[0010] EP 3266598 A1 discloses a method for permanent marking of optical spectacles. In a first step, an area of ​​the optical spectacles is treated with a laser beam to remove the surface coating in the detreated area. The movement of the laser beam can be programmed to produce a pattern or elements of a pattern to be drawn on the spectacles. Afterwards, ink is deposited in the detreated area by inkjet printing in order to form, for example, an ink pattern. By this method, the surface coating that prevents the ink from adhering is locally removed in order to reach a layer of the ophthalmic lens that has properties that allow the ink to be retained.

[0011] Disadvantageously, this method requires laser processing. In addition, although the ink is deposited into the recesses of the lens surface, it still sits on the surface and is therefore susceptible to damage due to insufficient adhesion.

[0012] US2018 / 0050549 A1 discloses a method for coloring an optical element with a non-uniform linear pattern. A gradual, visually discernible change in hue and / or color density over the entire area when the optical element is exposed to actinic radiation is achieved by depositing a photochromic composition via inkjet printing technology. However, since the photochromic composition is only present on the surface of the lens, it is also susceptible to damage due to insufficient adhesion. In addition, it is not possible to obtain locally resolved coloring with this method. WO 2018 / 113999 A1 also discloses a method for obtaining a gradient pattern throughout at least one surface of an optical substrate.

[0013] EP 1340108 B9 discloses a photochromic imbibition composition with a kinetic enhancement additive. Such a composition can be deposited on the surface of a substrate and the photochromic compound and the kinetic enhancement additive are thermally transferred together into the substrate. The composition may contain a carrier such as a solvent and / or a polymer resin, which mainly acts as a film-forming binder for the other components of the composition. However, the complexity of the composition may hinder the production and application of the composition. In addition, the diffused kinetic enhancement additive may adversely affect the lens properties.

[0014] WO 2020 / 226632 A1 discloses a thermal inkjet dye sublimation ink and a printing method, wherein the dye sublimation ink is printed from a thermal inkjet print head directly onto a textile to form an image or printed onto a transfer medium to form an image on the transfer medium, and then the image is transferred from the transfer medium to a textile substrate.

[0015] US2019 / 358919 A1 discloses a method for producing an optical article, comprising applying an imbibition composition having a dye to the surface of a substrate. The coated substrate is irradiated with heat from a heat source to form a thermal gradient across the coated substrate to diffuse the dye into the surface so as to form an imbibition substrate having a dye concentration gradient corresponding to the thermal gradient. However, the resolution of the imbibition area obtainable by the proposed method may not be sufficient for certain purposes, such as obtaining different structures with high resolution due to thermal conduction. In addition, according to US 2019 / 358919A1, the imbibition composition can have different amounts of dyes throughout the light-affected zone of the optical article (i.e., the portion of the optical article that has the ability to exhibit optical properties when light contacts or passes through the optical article). However, the disadvantage associated with this is the need for imbibition compositions with different amounts of dyes.

[0016] US2016 / 168404 A1 discloses a phase change ink composition for printing on an ophthalmic lens, comprising a linear hydrocarbon wax and a branched hydrocarbon wax; an amide, wherein the amide is present in an amount greater than about 25 wt %; a rosin ester; and a colorant.

[0017] US2014 / 099439 A1 discloses a method for producing an optical lens. The method includes: forming a mark outside a lens area set in a lens substrate, the mark being suitable for position alignment; pattern-forming a shielding layer above one main surface of the lens substrate, while controlling the formation position of the shielding layer based on the mark, the shielding layer having an opening at a predetermined position in the lens area; selectively processing the surface exposed from the bottom of the opening of the shielding layer by processing from above the shielding layer; and removing the shielding layer from above the lens substrate to form a processing pattern on one main surface side of the lens substrate by selective processing.

[0018] US2016 / 282637 A1 discloses a method for producing polarized goggles, which includes providing a polarizing film or a goggles blank having a polarizing film, wherein the polarizing film is made of a substrate film and a polarizing agent; immersing the polarizing film or the blank having the polarizing film in a solvent; and dissolving the polarizing agent from the polarizing film.

[0019] EP 3339008 A1 discloses a method for producing a polarizer with a stepped polarization or a continuous polarization gradient. The method comprises providing at least one polarizer comprising a substrate and at least one polarizer, and at least partially contacting the at least one polarizer with at least one reducing agent, the at least one reducing agent reacting with the at least one polarizer to provide at least one reduced polarizer. Summary of the invention

[0020] With respect to the mentioned prior art, it is an object of the present invention to provide a method for tinting an eyeglass lens substrate comprising a polymer lens material which allows tinting in an easily applicable, reproducible and permanent manner, for example to obtain patterns with a high spatial resolution.

[0021] A further object of the present invention is to provide a composition which can be used to achieve the coloring of ophthalmic lens substrates in an easily applicable, reproducible and permanent manner, for example in order to obtain patterns with a high spatial resolution.

[0022] A further object of the present invention is to provide a precursor for an ophthalmic lens substrate having improved tinting.

[0023] The first object is achieved by a method for intra-substrate tinting of a polymer spectacle lens substrate as claimed in claim 1, claim 20 or claim 37, further objects are achieved by a composition for intra-substrate tinting of a polymer spectacle lens substrate as claimed in claim 14 or claim 32, and a spectacle lens substrate comprising a polymer lens material as claimed in claim 16, claim 34 or claim 49. The dependent claims contain further developments of the invention.

[0024] Throughout this specification, the following definitions apply:

[0025] The terms "polymer" and "polymeric" refer to natural or synthetic substances consisting of large molecules composed of many repeating subunits. They include homopolymers and copolymers, such as graft polymers.

[0026] A spectacle lens is an ophthalmic lens that is worn in front of the eyeball but not in contact with the eyeball (DIN ISO 13666:2019, Section 3.5.2), wherein an ophthalmic lens is a lens intended for measuring, correcting and / or protecting the eye, or changing its appearance (DIN ISO 13666:2019, Section 3.5.1). Here, spectacle lenses include, but are not limited to, corrective lenses, protective lenses, absorbing lenses, transparent lenses, tinted lenses, uniformly tinted lenses, gradient tinted lenses, dual gradient tinted lenses, photochromic lenses, polarized lenses, balanced lenses, matching lenses, etc. as defined in Sections 3.5.3 to 3.5.13 of DIN ISO 13666:2019. In addition, according to Section 3.6 of DIN ISO 13666:2019, spectacle lenses can have various lens shapes, including, but not limited to, lenses in the form of curved surfaces, plano lenses, spherical lenses, cylindrical lenses, spherocylindrical lenses, toric lenses, aspherical lenses, non-toric lenses, etc.

[0027] The term "spectacle lens substrate" refers to a piece of optical material used during the manufacturing method of a spectacle lens, i.e. a precursor of a finished spectacle lens. A suitable precursor of a finished spectacle lens is, for example, a semi-finished lens blank, wherein the term "semi-finished lens blank" refers to a piece of optical material with one optically finished surface for making a spectacle lens (DIN ISO 13666:2019, section 3.8.1), in any case, the spectacle lens substrate as used herein exhibits at least one surface without any coating, such as an AR (anti-reflective) coating or a HC (hard coating) coating, which surface is to be used in the method described herein.

[0028] The term "lens material" refers to a material used to manufacture an eyeglass lens substrate. An eyeglass lens substrate may comprise a lens material or consist of a lens material.

[0029] The term "surface" refers to any layer of a three-dimensional spectacle lens substrate that is in direct contact with the environment. The surface can be considered as its boundary. The surface of the spectacle lens substrate includes its front surface, i.e., the front side; the side surface, i.e., the edge; and the back surface, i.e., the back side.

[0030] In the context of spectacle lenses, the expression "front surface" is used for the surface of the spectacle lens that faces away from the wearer's eye when mounted and worn in a spectacle frame (DIN ISO 13666:2019, section 3.8.13). In the context of semi-finished lens blanks, the expression "front surface" is used for the surface that will eventually become the front surface of the spectacle lens manufactured from the semi-finished lens blank. The curvature of a section of the front surface of a semi-finished lens blank used as starting object for manufacturing a spectacle lens may already be similar to the curvature of the spectacle lens to be manufactured.

[0031] In the context of spectacle lenses, the expression "back surface" is used for the surface of the spectacle lens that faces the wearer's eye when mounted and worn in a spectacle frame (DIN ISO 13666:2019, section 3.8.14). In the context of semi-finished lens blanks, the expression "back surface" is used for the surface that will eventually become the back surface of the spectacle lens manufactured from the semi-finished lens blank. The back surface of the semi-finished lens blank can be machined during the manufacturing method of the spectacle lens.

[0032] The term "composition" refers to a single material or a mixture of two or more different materials, such as a solution, a dispersion, etc. In the present invention, a composition comprising at least a carrier material is used. The composition can be composed of a carrier material or it can comprise other materials except the carrier material, such as one or more dye substances. For example, the composition can be composed of a mixture of a carrier material and one or more dye substances.

[0033] The term "locally resolved" means that different properties can be achieved with respect to the lateral dimensions of the surface of the spectacle lens substrate, e.g. a locally resolved tinted spectacle lens substrate exhibits tinted and non-tinted areas, e.g. in the form of patterns, indicia, letters, etc. Locally resolved may be used synonymously with the expression "patterned".

[0034] The term "intra-substrate" refers to a process in which at least a portion of the substrate is modified beneath the substrate surface, as opposed to a process in which only the substrate surface is modified (e.g., depositing a functional layer on the substrate surface). Depending on a number of influencing factors, such as temperature, time, characteristics of the support material, characteristics of the dye substance, etc., the modification of the substrate beneath the substrate surface can be performed, for example, to a depth of about 10 μm, about 50 μm, about 100 μm, or even about 500 μm below the surface.

[0035] The term "tinting" refers to a method of providing a spectacle lens substrate with tinting. A tinted spectacle lens substrate is a spectacle lens substrate for which at least a portion of the electromagnetic spectrum (e.g., the human perceptible illumination spectrum (380-780 nm) and / or other spectral ranges such as the NIR (780-3000 nm), UV-A (315-380 nm) and UV-B (280-315 nm) ranges) is attenuated due to the addition of a further substance (i.e., not by the polymer lens material itself). The amount of attenuation may be, for example, 6%-99%. In the case of attenuation within the human perceptible illumination spectrum, this may result in, for example, 1%-94% light transmittance in the tinted lens area as defined in DIN EN ISO 8980-3:2014-03. The light transmittance may be further affected by subsequently applied coatings such as AR coatings or HC coatings. Typically, tinting may be obtained by dipping or immersing the substrate in a tinting bath (i.e., a liquid dye solution). The colored substrate may exhibit a uniform coloration, ie, the colored area exhibits the same degree of transmission throughout, or the colored substrate may exhibit a coloration gradient, ie, the degree of transmission changes gradually within the colored area.

[0036] The term "support material" refers to a material suitable for being supported with a dye substance, ie the dye substance can be adsorbed and / or dissolved and / or dispersed or otherwise contained in the support material.

[0037] The term "congealing point" refers to the highest temperature at which a liquid or molten solid solidifies. For petroleum waxes, such as the waxes mentioned in this specification, it can be determined according to DIN ISO 2207:1983-12. The congealing point may be the same as the melting point.

[0038] The term "glass transition temperature" refers to the temperature below which fully or partially amorphous polymers are in a glassy or hard elastic, brittle state, and above which they are in a highly viscous or rubbery elastic, flexible state. According to IUPAC (Meille Stefano, V.; Allegra, G.; Geil Phillip, H.; He, J.; Hess, M.; Jin, J.-I.; Kratochvíl, P.; Mormann, W.; Stepto, R. (2011). "Definitions of terms relating to crystalline polymers (IUPAC Recommendations 2011)". Pure Appl. Chem. 83(10): 1831. doi: 10.1351 / PAC-REC-10-11-13.), the glass transition temperature is the temperature at which the glass transition occurs, i.e. the temperature at which a polymer melt changes into a polymer glass on cooling or a polymer glass changes into a polymer melt on heating. The glass transition temperature can be determined by differential scanning calorimetry (DIN EN ISO 11357-2: 2020-08). The term "glass transition temperature" as used in the present disclosure refers to the onset temperature of the glass transition temperature, which is the temperature at which the glass transition begins. It can be determined by extrapolating the relevant differential scanning calorimetry curve.

[0039] The term "pattern" refers to one or more macroscopic elements, such as numbers, letters of any type of graphics, graphic representations such as dots, symbols, etc. The pattern used in the exemplary embodiment is the letters "MARK". The pattern is formed by the surface area covered by the composition and the surrounding area not covered by the composition (i.e., does not contain the composition).

[0040] A material is considered hydrophobic if the static contact angle of a water droplet on the material surface is greater than or equal to 90°.

[0041] The term "heating" refers to the process of increasing temperature by input of energy.

[0042] The term “diffusion” refers to the physical process of spreading through or into surrounding materials by mixing with them. Diffusion can be viewed as the net movement of molecules from an area of ​​higher concentration to an area of ​​lower concentration. Diffusion is driven by a concentration gradient. The rate of diffusion depends on temperature.

[0043] The term "dye substance" refers to a colored substance that gives a spectacle lens substrate a permanent coloration or is used to permanently change the coloration of a spectacle lens substrate. In contrast to dye substances, photochromic substances correspondingly change color or coloration non-permanently (i.e., reversibly) when exposed to light of a specific wavelength. Dye substances are used in the coloring method as disclosed herein.

[0044] The term "solution" refers to a homogeneous mixture of two or more substances in liquid or solid state, i.e. all the substances form a single phase. In such a mixture, at least one substance, called solute, is dissolved in another substance, called solvent. The solubility of the solute in the solvent is temperature-dependent.

[0045] The term "saturated" refers to a solution in which the maximum possible amount of a solute is dissolved at a certain temperature. Accordingly, "dissolved to saturation" means dissolving the maximum possible amount of a solute in a solvent at a certain temperature.

[0046] In the context of depositing or applying a composition to a surface, the terms "directly" and "directly" mean that the composition is deposited or applied to the surface without any other material (eg, in the form of a layer) between the surface and the composition.

[0047] The term "inkjet printing" refers to a non-contact method of forming a pattern on a surface by discrete deposition of ink droplets. The term "ink" refers to any composition that can be deposited droplet by droplet, regardless of its color. In order to enable or promote the formation and deposition of droplets, it may be necessary to heat the ink to a certain temperature. Common procedures for inkjet printing include continuous inkjet and drop-on-demand methods, both of which are well known to those skilled in the art.

[0048] The term "polyethylene wax" refers to polyethylene having a waxy or fatty character due to a low molar mass of between 3,000 and 20,000 g / mol. "Oxidized polyethylene wax" can be obtained, for example, by oxidation of polyethylene wax with oxygen-containing gases.

[0049] The term "polypropylene wax" refers to a polypropylene having a waxy or fatty character due to a low molar mass between 3,000 and 20,000 g / mol. "Oxidized polypropylene wax" can be obtained, for example, by oxidizing a polypropylene wax with an oxygen-containing gas.

[0050] The term "shading agent" refers to a material suitable for adhering to and covering the surface of an ophthalmic lens substrate and thereby preventing contact between the dye substance and the surface areas of the ophthalmic lens substrate that are shaded by the shielding agent.

[0051] As used in this specification and the appended claims, the articles "a," "an," and "the" include plural referents unless expressly and unequivocally limited to one referent.

[0052] In a first aspect, the present invention provides a method for in-substrate tinting, such as locally resolved in-substrate tinting, of an ophthalmic lens substrate. The method comprises the steps of providing an ophthalmic lens substrate comprising a polymeric lens material, providing a composition comprising a polymeric carrier material, applying a pattern of the composition on a surface of the ophthalmic lens substrate, and heating the ophthalmic lens substrate to diffuse the dye substance between the carrier material and the lens material.

[0053] Thereafter, the composition may be removed from the surface of the ophthalmic lens substrate.

[0054] The method uses the diffusion of molecules of the dye substance between the carrier material and the lens material to obtain permanent in-substrate coloration. Since the composition is applied as a pattern on the substrate surface, locally resolved coloration can be obtained.

[0055] Preferably, the transfer of the dye substance from / into the lens material occurs exclusively by diffusion. This enables a good control of the transfer process.

[0056] In order to achieve proper diffusion, the process temperature should be appropriately selected. Since different materials with different properties can be combined within the scope of the present invention, it is not possible to indicate a specific temperature that can be used for all material combinations. Nevertheless, the skilled person will be able to determine the appropriate temperature taking into account the following limitations.

[0057] The temperature should be below the freezing point of the carrier material to avoid spreading of the molten carrier material on the substrate surface. This avoids deformation of the applied pattern due to gravity and the resulting degradation of the resolution, i.e., a high spatial resolution with high reproducibility can be obtained.

[0058] Furthermore, the temperature should be above the glass transition temperature of the lens material. This allows the dye substance to diffuse fast enough due to the soft state of the lens material while maintaining the physical dimensions of the substrate.

[0059] Apart from these limitations, the temperature may preferably be high enough so that the mobility of the dye molecules can be processed in the range of a few seconds to about 7 days. This allows for reasonable production times. More preferably, the temperature may be chosen in such a way that the diffusion of the dye substance from / to the lens material is an order of magnitude greater than the diffusion of exactly the same dye substance within the lens material. This avoids a degradation of the resolution and thus a locally resolved intra-substrate colored substrate with high resolution may be obtained.

[0060] Heating the spectacle lens substrate means reaching a temperature associated with the occurrence of the above process for a sufficiently long time, at least in the relevant area of ​​the spectacle lens substrate. In one embodiment, the heating temperature is kept constant during the heating step. Heating can be performed before and / or after applying the pattern of the composition. The heat source can be any conventional heat source, such as a hot air heat source, an infrared heat source, a convection heat source, or a microwave heat source, etc. In one embodiment, the heat source can be hot air, such as an oven. Heating can include the entire spectacle lens substrate or only a portion thereof. Heating can also be performed by applying a heated composition, so that the applied heated composition causes heating of the spectacle lens substrate.

[0061] Lens materials that can be used in the context of the present invention are lens materials conventionally used in optics and ophthalmology. Suitable lens materials are, for example, of the following types: polycarbonates, polyamides, polyimides, polysulfones, copolymers of poly(ethylene terephthalate) and polycarbonates, polyolefins, polymers and copolymers of diethylene glycol bis(allyl carbonate), (meth)acrylic polymers and copolymers and epoxy polymers and copolymers. The refractive index of the lens material may be, for example, 1.50, 1.60 or 1.67. Specific examples of suitable lens materials are poly(allyl diglycol carbonate) (CR-39) having a refractive index of 1.50 and poly(thiocarbamate) having a refractive index of 1.60 (MR-8) or 1.67 (MR-7).

[0062] Dye substances that can be used in the context of the present invention are dye substances conventionally used for lens tinting, such as disperse dye substances. They should exhibit sufficient light fastness and temperature stability. Suitable dye substances are, for example, Dianix Yellow AM-42, Serilene Scarlet G-LS, Dianix Turquoise S-BG, Terasil Blue 3RL-01, Teratop Blue GLF, Dorospers Red KKR, Teratop Pink 3G, Dianix Orange SG and CRX powder dyes such as Fluorescent Yellow 5944, Lemon Yellow 8043, Golden Yellow 3441, Orange 5945, Orange 3439, Scarlet 3443 , red 8153, pink 3442, purple 8168, purple 3735, lavender 3449, eggplant purple 8169, blue 3437, night color 3438, blue 5770, sky blue 8170, fennel green 6755, green 3450, green 3467, dark green 8171, ochre 8172, brown powder 3466, olive brown 3446, smoke color 3447, brown 6785, neutral gray 3444, iron gray 8173, gray-blue 3445, gray-green 5661, black 5894.

[0063] The carrier material that can be used in the context of the present invention is a polymeric substance, such as a polymer wax, which is suitable for containing a dye substance, for example by adsorbing or dissolving the dye substance in the carrier material. The carrier material can be a homopolymer, a copolymer or a polymer blend. Based on the diffusion of the dye substance between the carrier material and the lens material and the appropriate process temperature as described above, any polymeric carrier material that can be applied to the method can be used in combination with all lens materials and dye substances. In addition, the skilled person will be able to determine a suitable carrier material taking into account the following limitations.

[0064] The freezing point of the carrier material should be above the glass transition temperature of the lens material. The carrier material should be able to act as a solvent for the dye of interest. In addition, the composition comprising the carrier material should be easily removable from the substrate surface without damaging the substrate. Preferably, the carrier material should be non-toxic and environmentally friendly to facilitate handling of the carrier material and disposal of used or excess carrier material.

[0065] Polymer characteristics, such as chain length, functionality, branching, etc., should ensure

[0066] - strong and sufficient adhesion to the substrate when applying the pattern (e.g. by printing) and during the heating step;

[0067] - release of contained dye molecules without simultaneous diffusion into the lens material (e.g. detectable by FTIR spectroscopy) to avoid degradation of substrate properties;

[0068] -If used in hot melt printing processes, high print resolution is achieved by exhibiting appropriate physical properties (such as viscosity and surface tension) depending on the print head components used; and sufficient thermal stability in the print reservoir, i.e. no or negligible changes in properties that are critical to the inkjet process.

[0069] Suitable examples of carrier materials are polyethylene waxes and polypropylene waxes. For example, the carrier material may comprise at least one material selected from the group consisting of oxidized polyethylene waxes, non-oxidized polyethylene waxes, oxidized polypropylene waxes and non-oxidized polypropylene waxes, or may consist of at least one material selected from the group consisting of oxidized polyethylene waxes, non-oxidized polyethylene waxes, oxidized polypropylene waxes and non-oxidized polypropylene waxes. Specific examples of carrier materials are oxidized LDPE waxes Deurex EO 75K, Deurex EO 76K, Deurex EO 77K, Deurex EO 78K from the manufacturer Deurex AG, wherein the material properties are shown in Table 1.

[0070]

[0071] Table 1: Material properties of oxidized LDPE waxes.

[0072] The support material may be hydrophobic. This enables good adhesion to the substrate surface and thus facilitates coloring with high reproducibility.

[0073] The composition may include a dye substance contained in a carrier material. For example, the dye substance may be dissolved, dispersed and / or adsorbed in the carrier material. In this case, the dye substance may be transferred from the carrier material to the lens material by diffusion.

[0074] This enables active coloring of the substrate with the dye in a locally resolved manner. As the dye diffuses into the substrate, the coloring takes place within the substrate as a permanent coloration.

[0075] Preferably, the composition can exhibit a uniform dye material concentration throughout the composition. Therefore, there is no need to prepare different compositions with different amounts or concentrations of dye material. Local resolution of coloration within the substrate can be obtained by applying only the corresponding composition pattern.

[0076] It may be advantageous if the composition comprises a saturated dye-loaded carrier material, i.e. if the carrier material is saturated with the dye species. By using a saturated dye-loaded carrier material, the diffusion rate of the dye from the composition into the lens material can be more reliably predicted, resulting in tinting with enhanced reproducibility.

[0077] Furthermore, the lens material may contain dye substances. In this case, the dye substances can be transferred from the lens material to the carrier material by diffusion, hereinafter also referred to as bleaching process.

[0078] This enables bleaching of the colored substrate in a locally resolved manner. As the dye diffuses from the interior of the substrate into the carrier material, bleaching occurs within the substrate and colored substrates with permanent bleaching patterns, i.e. locally resolved intra-substrate colored spectacle lens substrates, are obtainable.

[0079] The two diffusion processes, ie the diffusion of the dye substance from the substrate and the diffusion into the substrate, can be combined in the same method step or in consecutive method steps. This allows the use of different colors and / or patterns to enhance the locally resolved coloration within the substrate.

[0080] Preferably, the pattern of the composition can be applied directly on the surface of the eyeglass lens substrate. No auxiliary layer such as a primer layer is required. Therefore, the method is easy to apply and cost-effective to implement.

[0081] The method can be carried out in such a way that a coloring gradient is obtained, for example, by applying different amounts of dye substances per unit area on the spectacle lens substrate. For example, this can be done by locally printing multiple layers of a composition comprising a dye substance on top of each other.

[0082] In another embodiment, the coloring gradient can be obtained by locally resolved heating, ie the heating pattern for influencing the diffusion process is applied in such a way that a gradient can be obtained.

[0083] The possibility of forming gradients expands the range of locally resolved intra-substrate colorations that can be used.

[0084] The method may comprise further method steps, hereinafter referred to as masking procedure: providing a masking agent, applying a pattern of the masking agent onto the surface of the spectacle lens substrate to obtain a partially masked spectacle lens substrate, immersing the partially masked spectacle lens substrate in a tinting bath comprising a dye substance (e.g. a solution of a dye substance) so that unmasked areas of the partially masked spectacle lens substrate are tinted, removing the tinted, partially masked spectacle lens substrate from the tinting bath and removing the masking agent from the surface of the tinted, partially masked spectacle lens substrate.

[0085] The masking procedure can be carried out before, at the same time or after the above steps according to the diffusion principle. By adopting the masking procedure, additional in-substrate coloring, for example using different dyes, is available.

[0086] The properties required of the shielding agent depend on the lens material. A skilled person will be able to determine a suitable shielding agent taking into account the following constraints depending on the lens material used.

[0087] The screening agent should be sufficiently adhered to the substrate surface to avoid the coloring bath from contacting the substrate surface in the shielded area. In addition, the screening agent should be easily removable from the substrate surface without damaging the substrate. If used simultaneously with the heating step, the screening agent should not change its physical dimensions during the heating period to ensure high resolution. Therefore, its coagulation point should be higher than the heating temperature.

[0088] For example, the shielding agent may be a composition comprising a carrier material, i.e. the composition may be used for the diffusion process of the dye substance to / from the lens material and simultaneously act as a shielding agent. The composition may comprise only a carrier material or the composition may comprise a carrier material and a dye substance. This enables high flexibility in locally resolved intra-substrate coloring, for example different colors and / or patterns may be easily formed in a single process with high reproducibility.

[0089] Preferably, the pattern can be applied by inkjet printing. This applies to patterns employed in diffusion procedures as well as in masking procedures. Inkjet printing allows the pattern to be applied to the substrate surface with high resolution and reproducibility.

[0090] In case of using a composition comprising a dye substance contained in a carrier material, the amount of dye substance per unit area of ​​the substrate lens material can be easily predetermined by selecting an appropriate print volume (size of the print droplets, number of printing steps, etc.). Thus, by selecting the print characteristics, the final appearance of the tinted ophthalmic lens substrate can be accurately determined even before the heating step. Furthermore, inkjet printing can be easily automated.

[0091] In concrete development, the method can include preparation composition.Therefore, the method can include the following steps: carrier material and dye substance are provided, the carrier material is heated to be higher than its coagulation point, the dye substance is dissolved in the molten carrier material to obtain the carrier material of the loaded dye, and the carrier material of the loaded dye is cooled to room temperature.In other embodiments, the dye substance can be dissolved in the molten carrier material until saturated to obtain the carrier material of saturated loaded dye.

[0092] With regard to the properties and selection of suitable carrier materials and dye substances and their advantages, reference is made to the above explanations describing the process for in-substrate coloring of spectacle lens substrates.

[0093] The proposed method allows for simple and cost-effective preparation of the composition using common equipment.

[0094] Optionally, the solution of the dye carrier may be filtered to remove any dye particles that may be present. Thus, a high quality composition may be obtained which can be used for in-substrate coloring of ophthalmic lens substrates with high resolution and reproducibility. If used in printing procedures such as inkjet printing, the filtration temperature should preferably not be higher than the temperature used for printing to avoid the formation of precipitates in the print head.

[0095] According to another aspect of the present invention, a composition for intra-substrate coloring (e.g., locally resolved intra-substrate coloring) of a polymeric eyeglass lens substrate is provided. The composition comprises a carrier material loaded with a dye. The carrier material comprises at least one material selected from the group consisting of: oxidized polyethylene wax, non-oxidized polyethylene wax, oxidized polypropylene wax, and non-oxidized polypropylene wax. The composition allows for the transfer of dye substances from the carrier material to the lens material by diffusion after the composition is applied to the surface of an eyeglass lens substrate comprising a polymeric lens material.

[0096] The composition can exhibit a uniform concentration of dye material throughout the composition.

[0097] Alternatively, the composition may comprise a saturated dye-loaded carrier material, ie a saturated solution of the dye substance in the carrier material.

[0098] With regard to the properties and selection of suitable carrier materials and dye substances and their advantages, reference is made to the above explanations describing the process for in-substrate coloring of spectacle lens substrates.

[0099] According to another aspect of the present invention, there is provided an eyeglass lens substrate comprising a polymer lens material. The eyeglass lens substrate exhibits a pattern of a composition comprising a polymer carrier material applied to a surface of the eyeglass lens substrate. The composition may be applied directly to the surface of the eyeglass lens substrate.

[0100] The carrier material comprises at least one material selected from the group consisting of oxidized polyethylene wax, non-oxidized polyethylene wax, oxidized polypropylene wax and non-oxidized polypropylene wax. The composition allows the transfer of dye substances from the carrier material to the polymer lens material and / or the transfer of dye substances from the lens material to the carrier material by diffusion when the ophthalmic lens substrate is heated.

[0101] Optionally, the freezing point Tc(carrier) of the polymeric carrier material may be higher than the glass transition temperature Tg(lens) of the polymeric lens material.

[0102] The composition may include a dye substance contained in a carrier material. The composition may exhibit a uniform concentration of the dye substance throughout the composition.

[0103] Such a spectacle lens substrate may be regarded as a precursor of a spectacle lens substrate with in-substrate coloration obtainable by any of the above-described methods for in-substrate coloration of a spectacle lens substrate.

[0104] With regard to the properties and selection of suitable materials and methods for applying the pattern and their advantages, reference is made to the above explanations describing the methods for in-substrate coloring of spectacle lens substrates. BRIEF DESCRIPTION OF THE DRAWINGS

[0105] Further features, characteristics and advantages of the present invention will become apparent from the following description of embodiments with reference to the accompanying drawings.

[0106] Figure 1 The temperature-dependent physicochemical behavior of lens materials and carrier materials is shown.

[0107] Figure 2 The diffusion of the dye from the carrier material into the lens material as a function of temperature, time and concentration is shown (two-component system).

[0108] Figure 3 The diffusion of dye from the carrier material into the lens material as a function of temperature, time and concentration is shown (three-component system).

[0109] Figure 4A method for in-substrate tinting of an ophthalmic lens substrate using dye diffusion from a carrier material into the lens material is shown.

[0110] Figure 5 A 2D / cross-sectional view showing the coloring process using a dye-loaded support material.

[0111] Figure 6 The diffusion of dye from the lens material into the carrier material is shown as a function of temperature, time and concentration.

[0112] Figure 7 A method for in-substrate tinting of an ophthalmic lens substrate using dye diffusion from the lens material into a carrier material is shown.

[0113] Figure 8 A 2D / cross-sectional view of the pixel-level intra-substrate bleaching process is shown.

[0114] Fig. 9 The masking procedure is shown.

[0115] Fig.10 A 2D / cross-sectional view of a lens tinting using a shading procedure is shown.

[0116] Fig.11 is a flow chart illustrating a method for preparing an in-substrate tinted composition for a polymeric ophthalmic lens substrate.

[0117] Fig.12 A schematic diagram of a composition for in-substrate tinting of a polymeric ophthalmic lens substrate is shown. DETAILED DESCRIPTION

[0118] Each of the methods described herein for in-substrate tinting of spectacle lens substrates replaces currently used tinting methods with regard to spatial resolution, allowing the use of reliable and mature process steps to greatly expand the portfolio of tinted lenses. The method can be used for a variety of different polymer spectacle lens substrates (e.g., with refractive indices of 1.50, 1.60 and 1.67) and a variety of dye substances. In addition to this, the effort required for implementation in lens production is minimal, since many process parameters are known from standard procedures and the machines required for lens marking and in-substrate tinting are readily available.

[0119] Among other things, the following applications can be realized by using the proposed method for in-substrate tinting of spectacle lens substrates:

[0120] -Customer samples distributed to opticians with corporate identity markings (logo etc.) coloured into the substrate.

[0121] -Production customer orders (including "clear lenses") can be customized with in-substrate tinted markings.

[0122] - Customizable free-form patterns allow for customer-specific darkening patterns (ie for photophobic areas) if linked to a computational engine.

[0123] - Free-form, multi-color gradient lenses are available.

[0124] -Marketing and cosmetic customization of eyeglass lens substrates with different refractive indices.

[0125] - Lens identification: The colored characters in the substrate can be recognized by OCR (Optical Character Recognition) software, making this method applicable for lens marking, marking identification data to the spectacle lens substrate.

[0126] Figure 1 The temperature-dependent physicochemical behavior of lens material 2 and carrier material 4 (loaded with dye and not loaded with dye) is shown. As the temperature increases, the carrier material changes from a solid state to a liquid molten state above its freezing point Tc(carrier). The lens material likewise changes from a solid brittle state (below its glass transition temperature Tg(lens)) to a solid soft state (above its glass transition temperature Tg(lens)). At even higher temperatures, the lens material may melt or decompose ( Figure 1 not shown).

[0127] In order to transfer the dye substance 7 between the carrier material 4 and the lens material 2 quickly enough by diffusion, a temperature within a specified "overlap" range is preferred, i.e. above the glass transition temperature Tg(lens) of the lens material 2 but below the freezing point Tc(carrier) of the carrier material 4.

[0128] Apart from Figure 1 In addition to the phase transition depicted in , further phase transitions may occur, for example due to recrystallization.

[0129] References below Figures 2 to 5 A first embodiment of a method 100 for in-substrate tinting is described. This first embodiment employs a composition 3 comprising a dye substance 7 contained in a carrier material 4. To obtain in-substrate tinting, the dye substance 7 is transferred from the carrier material 4 into the lens material 2 by diffusion.

[0130] Figure 2The basic diffusion process in a two-component system is shown, e.g. the composition 3 is considered as one component and the lens material 2 is considered as the other component. The basic driving force that makes this process work is the tendency of the system to approach its thermodynamic equilibrium in terms of the distribution of the dye substance 7 between the carrier material 4 and the lens material 2. The diffusion process can be influenced by choosing appropriate starting conditions, such as differences in dye concentration / loading, and appropriate kinetic diffusion parameters, such as temperature, polymer hardness, etc. In the following two simplified different scenarios, the diffusion of the dye substance 7 dissolved in the carrier material 4 and the diffusion of the dye substance 7 dispersed in the carrier material 4 are described.

[0131] Figure 2 The diagram depicted in shows three time periods T1, T2 and T3 respectively.

[0132] In the time period T1, the composition 3 containing the dye-loaded carrier material 4, 7 is applied to the surface 6 of the spectacle lens substrate 1. If the composition 3 is applied in a molten state, for example by inkjet printing, the temperature of the spectacle lens substrate 1 may locally rise above its Tg (lens), but this is negligible since the average temperature of the spectacle lens substrate 1 is still below its Tg (lens). This leads to a situation where the molecules of the dye substance 7 contained in the carrier material 4 want to (thermodynamically) penetrate the surface 6 of the spectacle lens substrate 1, but are kinetically hindered (infinitely slow). The composition 3 solidifies on the surface 6.

[0133] After a certain period of time, the period of time T2 is reached. In the period of time T2, the spectacle lens substrate 1 is heated to a temperature T that is higher than the glass transition temperature Tg (lens) but lower than the freezing point Tc (carrier). The diffusion coefficient of the dye substance 7 in the carrier material 4 and in the lens material 2 increases by several orders of magnitude. The kinetic hindrance of the system approaching its equilibrium state is reduced and the dye molecules penetrate from the carrier material 4 into the lens material 2. The concentration of the dye substance 7 in the carrier material 4 depending on the time t is shown by the curve [A] (t). The concentration of the dye substance 7 in the lens material 2 depending on the time t is shown by the curve [B] (t).

[0134] After a certain period of time, a period of time T3 is reached. In the period of time T3, the system has approached its equilibrium state and the additional time given for diffusion has a negligible effect on the dye absorption and thus on the spectral characteristics of the tinted lens material 2, 7. The diffusion of the dye substance 7 within the lens material 2 continues at an elevated temperature above the glass transition temperature Tg(lens) of the lens material 2. Therefore, if further dye diffusion is to be avoided, the lens material 2 should be cooled to below its Tg(lens).

[0135] In such Figure 2In the case shown with two components, a high concentration of the dye substance 7 in the carrier material 4 is desirable for a rapid transfer of the dye substance 7 .

[0136] However, if the dye substance 7 is not dissolved in the carrier material 4 but adsorbed to or dispersed within the carrier material 4, the entire system can be regarded as a three-component system (carrier material 4, reservoir of dye substance 7 and lens material 2). In this case, a low maximum dye concentration and fast kinetics in the carrier material 4 may be advantageous. For this process, a carrier material 4 with a lower affinity (activity) for the dye substance 7 may be beneficial.

[0137] Figure 3 The basic diffusion process in a three-component system is shown in Figure 2. Figure 2 As shown, it can be divided into three time periods T1, T2 and T3.

[0138] The time period T1 is an initial state with a low temperature, i.e., a temperature below the glass transition temperature Tg(lens) of the lens material 2 and the freezing point Tc(carrier) of the carrier material 2. The average temperature of the spectacle lens substrate 1 is still below its Tg(lens).

[0139] In the time period T2, the spectacle lens substrate 1 is heated to a temperature T above the glass transition temperature Tg(lens). The carrier material 4 exhibits a freezing point Tc(carrier) above this heating temperature. The diffusion coefficients of the dye substance 7 in the carrier material 4 and in the lens material 2 increase by several orders of magnitude, but are still different, as can be concluded from the different trends of the curve [W](t) showing the concentration of the dye substance 7 in the dye reservoir as a function of the time t and the curve [B](t) showing the concentration of the dye substance 7 in the lens material 2 as a function of the time t. In the time period T3, the system approaches its equilibrium state. As Figure 2 As shown, the concentration of the dye substance 7 in the carrier material 4 as a function of time t is illustrated by the curve [A](t).

[0140] Figure 4 A method 100 for intra-substrate coloring, in particular locally resolved intra-substrate coloring, of a spectacle lens substrate 1 using dye diffusion from a carrier material 4 into the lens material 2 is shown.

[0141] In step S1, a spectacle lens substrate 1 is provided. The spectacle lens substrate 1 comprises a polymer lens material 2. In a specific example, the lens material 2 is a poly(allyl diglycol carbonate) or a poly(thiocarbamate) having a refractive index of 1.50, 1.60 or 1.67. The method 100 does not require any specific coating or material on the surface 6 of the spectacle lens substrate 1. However, the surface 6 can be cleaned by common cleaning methods before the next step.

[0142] Furthermore, a swelling agent may be applied to the surface 6 of the spectacle lens substrate 1, for example by immersing the entire spectacle lens substrate 1 in a bath containing or consisting of the swelling agent. Possible swelling agents are water, for example used with poly(allyl diglycol carbonate), and benzyl alcohol, for example used with poly(thiocarbamate). The swelling agent may facilitate the diffusion of the dye substance 7 into the spectacle lens substrate 1.

[0143] In step S3, the composition 3 is Figure 4 and Figure 5 A pattern 5 depicted with the letters "MARK" is applied to the surface 6 of the spectacle lens substrate 1. The composition 3 is applied in step S2 (see Figure 5 ) is provided in and comprises a polymer carrier material 4 and a dye substance 7 contained in the carrier material 4. In a specific example, the polymer carrier material 4 is an oxidized polyethylene wax. For example, one of the oxidized LDPE waxes Deurex EO 75K, Deurex EO 76K, Deurex EO 77K or Deurex EO 78K of the manufacturer Deurex can be used. The coagulation point Tc (carrier) of the carrier material 4 is higher than the glass transition temperature Tg (lens) of the lens material 2. The dye substance 7 used in the specific example is one of Dianix yellow AM-42, Serilene scarlet G-LS, Dianix turquoise S-BG and Terasil blue 3RL-01.

[0144] The pattern 5 can be applied by inkjet printing. In a specific example, the inkjet printing is performed using the X-Cube digital lens inking device from the manufacturer Tecoptique. This device allows the pattern 5 to be printed on any type of lens. However, other printing devices can also be used. The X-Cube device can be used in a manual mode or in an automatic mode that allows the method 100 to be automated. The printing characteristics of the X-Cube can be found in Table 2.

[0145]

[0146]

[0147] Table 2: X-Cube printing features.

[0148] The X-Cube device is used with an M-series industrial piezoelectric carrier jet printhead manufactured by Xerox, corp (Xerox M1). This printhead is ideal for demanding applications and can jet fluids at temperatures ranging from ambient to 140°C. The characteristics of the printhead can be found in Table 3.

[0149] Operation parameters Units of measurement Xerox M Series Number of addressable nozzles 880 4-color (closest) nozzle spacing Micron (dpi) 337.5(75) Single color nozzle spacing Micron (dpi) 84.4(300) Nozzle row 16 Meniscus pressure millibar -3 to -8 Droplet size Picoliter 15 to 30 Nominal drip rate m / s Up to 10 Maximum operating temperature ℃ 140 Fluid viscosity cP 6 to 11 Maximum operating frequency kHz 43kHz

[0150] Table 3: M-Series printhead characteristics.

[0151] The printing distance, i.e. the distance between the surface 6 and the print head, is selected between 0.5 and 3 mm, the printing resolution is 900 dpi, and the number of printing steps is 3. However, the printing resolution and the number of printing steps can vary, for example between 25 and 1200 dpi and between 1 and 10 steps, respectively. The printing temperature is between 120° C. and 140° C.

[0152] Reference again Figure 4 , the method 100 continues with step S4, wherein the spectacle lens substrate 1 is heated to a temperature above the glass transition temperature Tg(lens) of the lens material 2 and below the freezing point Tc(carrier) of the carrier material 4 using a heating device, for example, in an air oven. The spectacle lens substrate 1 can be heated to a temperature between 40° C. and 100° C., for example, and preferably between 70° C. and 100° C.

[0153] The heating temperature in a specific example is about 90° C. for a period of 20 minutes to several hours, depending on the desired tinting intensity, i.e. until the spectacle lens substrate 1 has received the desired tinting. Heating allows the dye substance 7 to diffuse from the carrier material 4 into the lens material 2, i.e. the dye substance 7 is transferred from the carrier material 4 into the lens material 2.

[0154] After heating, the residual composition 3 is removed from the surface 6 of the spectacle lens substrate 1 (step S5). This can be done, for example, by wiping with a paper towel or cleaning in the presence of ethanol, isopropanol, acetone or any solvent that dissolves the composition 3 but does not penetrate the spectacle lens substrate 1. Rinsing can be combined with ultrasonic cleaning in an ophthalmic lens cleaning machine. The ultrasonic bath can be heated.

[0155] After the composition 3 is removed from the surface 6, a spectacle substrate lens 1 is obtained with locally resolved in-substrate coloration (letters "MARK" in step S5). Figure 4 As shown in the enlarged view of FIG. 6 , the dye substance 7 diffuses into the surface 6. The coloration obtained is therefore located within the substrate and provides a permanent locally resolved coloration.

[0156] Figure 5 Steps S1 to S5 of the method 100 of the first embodiment are shown in 2D / cross-sectional view to better illustrate the diffusion of the dye substance 7 into the spectacle lens substrate 1. For further explanation, please refer to Figure 4 Description.

[0157] References below Figures 6 to 8A second embodiment of a method 100 for in-substrate coloring, in particular locally resolved in-substrate coloring, is described. In this second embodiment, the lens material 2 contains a dye substance 7. To obtain the in-substrate coloring, the dye substance 7 is transferred by diffusion from the lens material 2 into the carrier material 4. The spectacle lens substrate 1 is bleached locally resolved, for example pixel-wise.

[0158] Figure 6 The relevant diffusion process is shown. The basic chemical and physical principles used in the first embodiment are also relevant for the second embodiment. Once again, the drive of the system towards an equilibrium state of the dye substance 7 between the carrier material 4 and the lens material 2 is utilized. In contrast to the first embodiment, the starting conditions differ in that a dye-free carrier material 4 and a pre-dyed spectacle lens substrate 1 are used.

[0159] The diffusion process can be influenced by choosing appropriate starting conditions, such as differences in dye concentration / loading, and appropriate kinetic diffusion parameters, such as temperature, polymer stiffness, etc.

[0160] Figure 6 The graph depicted in shows three time periods T1, T2 and T3, respectively.

[0161] In the time period T1, the composition 3 containing the dye-free carrier material 4 is applied to the surface 6 of the spectacle lens substrate 1. If the composition 3 is applied in a molten state, for example by inkjet printing, the temperature of the spectacle lens substrate 1 may locally rise above its glass transition temperature Tg(lens), but this is negligible since the average temperature of the spectacle lens substrate 1 is still below its Tg(lens). This leads to a situation where the molecules of the dye substance 7 contained in the lens material 2 want to (thermodynamically) penetrate the surface 6 of the spectacle lens substrate 1, but are kinetically hindered (infinitely slow). The composition 3 solidifies on the surface 6.

[0162] After a certain period of time, the period of time T2 is reached. In the period of time T2, the spectacle lens substrate 1 is heated to a temperature T higher than the glass transition temperature Tg (lens). The carrier material 4 exhibits a freezing point Tc (carrier) higher than this heating temperature T. The diffusion coefficient of the dye substance 7 in the lens material 2 and in the carrier material 4 increases by several orders of magnitude. The kinetic hindrance of the system approaching its equilibrium state is reduced and the dye molecules penetrate from the lens material 2 into the carrier material 4. The concentration of the dye substance 7 in the carrier material 4 depending on the time t is shown by the curve [A] (t). The concentration of the dye substance 7 in the lens material 2 depending on the time t is shown by the curve [B] (t).

[0163] After a certain period of time, time period T3 is reached. In time period T3, the system has approached its equilibrium state and the additional time given for diffusion has a negligible effect on the dye absorption and thus on the spectral properties of the spectacle lens substrate 1. Diffusion of the dye substance 7 within the lens material 2 continues at an elevated temperature above the glass transition temperature Tg(lens) of the lens material 2. Therefore, if further dye diffusion is to be avoided, the lens material 2 should be cooled to below its Tg(lens).

[0164] In the second embodiment, bleaching does not yield a completely dye-free lens material 2, because at elevated temperatures, both dye diffusion towards the surface 6 and diffusion of the dye substance 7 within the lens substrate occur simultaneously. However, due to favorable bleaching kinetics (k_bleach >> k_bulk diffusion) and appropriate choice of process temperature, the optical properties of the remaining dye substance 7 in the lens material 2 are negligible. Technically, this can be ensured by preparing a pre-dyed spectacle lens substrate 1, which will later be bleached in such a way that the dye substance 7 is contained in the depth of the first few microns. This can be achieved by relatively low temperatures during pre-dying (tinting). The pre-dyed spectacle lens substrate 1 can then be easily bleached as described above. If necessary, the diffusion depth of the remaining dye substance 7 in the lens material 2 can be increased by oven cycles at higher temperatures.

[0165] Figure 7 A method 100 is shown for intra-substrate coloring, in particular locally resolved intra-substrate coloring, of a spectacle lens substrate 1 using dye diffusion (bleaching method) from a lens material 2 into a carrier material 4 .

[0166] In step S1, a spectacle lens substrate 1 is provided. The spectacle lens substrate 1 comprises a polymer lens material 2. In a specific example, the lens material 2 is a poly(allyl diglycol carbonate) or a poly(thiocarbamate) having a refractive index of 1.50, 1.60 or 1.67. The lens material 2 contains a dye substance 7, i.e., a pre-dyed spectacle lens substrate 1 is used. The dye substance 7 used in the specific example is one of Dianix Yellow AM-42, Serilene Scarlet G-LS, Dianix Turquoise S-BG and Terasil Blue 3RL-01. The pre-dyed spectacle lens substrate 1 is obtainable by a well-known tinting method using a tinting bath.

[0167] The method 100 does not require any particular coating or material on the surface 6 of the spectacle lens substrate 1. However, the surface 6 may be cleaned by common cleaning methods before the next steps.

[0168] In step S3, the composition 3 is Figure 7 and Figure 8 The pattern 5 depicted by the letters "MARK" is applied to the surface 6 of the spectacle lens substrate 1. The composition 3 is applied in step S2 (see Figure 8 ) and comprises a polymer carrier material 4 but does not comprise a dye substance 7. In a specific example, the polymer carrier material 4 is an oxidized polyethylene wax. For example, one of the oxidized LDPE waxes Deurex EO 75K, Deurex EO 76K, Deurex EO 77K or Deurex EO 78K of the manufacturer Deurex can be used. The softening point Ts (carrier) of the carrier material 4 is higher than the softening point Ts (lens) of the lens material 2. The coagulation point Tc (carrier) of the carrier material 4 is higher than the glass transition temperature Tg (lens) of the lens material 2.

[0169] The pattern 5 can be applied by inkjet printing. For available printing equipment, refer to the description of the first embodiment and Tables 2 and 3.

[0170] The method 100 continues with step S4, in which the spectacle lens substrate 1 is heated using a heating device, for example in an air oven, to a temperature above the glass transition temperature Tg(lens) of the lens material 2 but below the freezing point Tc(carrier) of the carrier material 4. The spectacle lens substrate 1 can be heated, for example, to a temperature between 40°C and 100°C, preferably between 70°C and 100°C.

[0171] The heating temperature in a specific example is about 90° C. for a period of 1 minute to 1 day, depending on the desired bleaching intensity, i.e. until the desired bleaching of the spectacle lens substrate 1 has been achieved. Heating allows the dye substance 7 to diffuse from the lens material 2 into the carrier material 4, i.e. the dye substance 7 is transferred from the lens material 2 into the carrier material 4.

[0172] After heating, the composition 3 comprising the carrier material 4 and some dye substance 7 is removed from the surface 6 of the spectacle lens substrate 1 (step S5). This can be done, for example, by wiping with a tissue or washing in the presence of ethanol, isopropanol, acetone or any solvent that dissolves the composition 3 but does not penetrate the spectacle lens substrate 1. Rinsing can be combined with ultrasonic cleaning in an ophthalmic lens cleaning machine. The ultrasonic bath can be heated.

[0173] After the composition 3 is removed from the surface 6, a spectacle substrate lens 1 is obtained with locally resolved in-substrate coloration (letters "MARK" in step S5). Figure 7 As shown in the enlarged view of FIG. 1 , the dye substance 7 is locally removed from the pre-dyed spectacle lens substrate 1. The bleaching obtained is therefore localized within the substrate and provides a permanent, locally resolved coloration.

[0174] Figure 8Steps S1 to S5 of the method 100 of the second embodiment are shown in a 2D / cross-sectional view to better illustrate the diffusion of the dye substance 7 from the spectacle lens substrate 1 into the carrier material 4. For further explanation, please refer to Figure 7 Description.

[0175] The first and second embodiments can be combined, ie the coloring according to the first embodiment and the bleaching according to the second embodiment can be performed sequentially or overlapping in time.

[0176] Fig. 9 and Fig.10 The masking procedure of the third embodiment of the present invention is shown. The masking procedure can be combined with one or both of the methods 100 of the first and second embodiments, respectively, which can be referred to in the reference Fig. 9 and Fig.10 The steps described are carried out before or after or (partially) overlapping.

[0177] In step S1, a spectacle lens substrate 1 is provided. The spectacle lens substrate 1 comprises a polymer lens material 2. In a specific example, the lens material 2 is a poly(allyl diglycol carbonate) or a poly(thiocarbamate) having a refractive index of 1.50, 1.60 or 1.67. The method 100 does not require any specific coating or material on the surface 6 of the spectacle lens substrate 1. However, the surface 6 may be cleaned by a common cleaning method before the next step. The spectacle lens substrate 1 may have been treated according to the first and / or second embodiment.

[0178] In step S7, a pattern 5 of a masking agent 8 is applied to the surface 6 of the spectacle lens substrate 1. The masking agent 8 was provided in the previous step S6 (see Fig.10 ). The pattern 5 leaves unmasked areas 11 of the surface 6 free of the masking agent 8. Fig. 9 and Fig.10 In , the letters "MARK" correspond to the unmasked areas 11. The pattern 5 can be applied by inkjet printing. For available printing equipment, reference is made to the description of the first embodiment and to Tables 2 and 3. At the end of step S7, a partially masked spectacle lens substrate 9 is obtained.

[0179] In step S8, the partially shaded spectacle lens substrate 9 is immersed in a tinting bath 10 containing the dye substance 7. The partially shaded spectacle lens substrate 9 is allowed to remain in the tinting bath 10 until the desired tinting is obtained. This may last from a few minutes to a few hours.

[0180] In step S9, the tinted, partially masked spectacle lens substrate 9 is removed from the tinting bath 10 and the masking agent 8 is removed from the surface of the tinted, partially masked spectacle lens substrate 9. The latter can be done, for example, by wiping with a tissue or cleaning in the presence of ethanol, isopropanol, acetone or any solvent that dissolves the masking agent 8 but does not penetrate the spectacle lens substrate 1. Rinsing can be combined with ultrasonic cleaning in an ophthalmic lens cleaning machine.

[0181] Fig.10 Steps S1 and S6 to S9 of the method 100 of the third embodiment are shown in 2D / cross-sectional view to better illustrate the masking process. For further explanation, please refer to Fig. 9 Description.

[0182] Fig.11 A flow chart illustrating a method 200 for preparing a composition 3 for intra-substrate coloring, in particular local resolution intra-substrate coloring, of a polymeric spectacle lens substrate 1 is shown. During a first step S10, a carrier material 4 and a dye substance 7 are provided.

[0183] In the specific example, the carrier material 4 is an oxidized emulsified polyethylene wax from the manufacturer Deurex EO 78K, which was purified by successive liquid-liquid extractions before further use. As dye substance 7, Terasil Blue 3RL-01 was used.

[0184] During step S11, the support material 4 is heated above its freezing point. In step S12, the dye substance 7 is dissolved in the molten support material 4. At the end of step S12, the dye-loaded support material 4, 7 is obtained. Steps S11 and S12 can be combined and the dye-loaded support material 4, 7 can be purified. In step S13, the dye-loaded support material 4, 7 is cooled to room temperature.

[0185] In a specific embodiment, 10wt% (weight percentage) Terasil blue 3RL-01 and 90wt% Deurex EO78K are mixed in a beaker, heated to a maximum of 120°C and stirred for 24h under atmospheric pressure. Then, the mixture is hot filtered at 120°C to remove the particles of the remaining dye material 7. The filtration temperature should not be higher than the temperature during printing to avoid solid precipitation in the print head. After filtering, the carrier material 4,7 of the molten load dye is cast on an aluminum foil to solidify. The carrier material 4,7 of the solidified load dye is broken into pieces by hand.

[0186] The prepared dye-loaded support material 4, 7 is brittle at room temperature and exhibits a melting point of 85° C. The maximum particle size is about 40 μm. It is non-toxic and dark green (dye related).

[0187] The obtained dye-loaded carrier material 4, 7 can now be loaded into a print head assembly to carry out a method 100 for in-substrate coloring of an ophthalmic lens substrate 1, wherein the composition 3 comprises a dye substance 7 contained in the carrier material 4 and wherein the dye substance 7 is transferred from the carrier material 4 into the lens material 2 by diffusion, e.g. Figure 4 and Figure 5 Method 100 is described.

[0188] If necessary, a quick feasibility test can be carried out by manually applying some dye-loaded carrier materials 4, 7 to the spectacle lens substrate 1 and heating them to a maximum of 90° C. After about 30 minutes at 90° C., the dye-loaded carrier materials 4, 7 are removed with absolute ethanol and a partially blue-tinted spectacle lens substrate 1 is obtained.

[0189] Fig.12 A composition 3 for intra-substrate coloring, in particular locally resolved intra-substrate coloring, of a polymeric spectacle lens substrate 1 is schematically shown. The composition 3 can be prepared, for example, by Fig.11 The described method 200 is obtained. The composition 3 consists of particles of a carrier material 4 and a dye substance 7 dissolved in the carrier material 7.

[0190] The invention advantageously enables "printing" of defined patterns 5 for locally resolved tinting or bleaching of a spectacle lens substrate 1, within the substrate and, for example, with high resolution. The method 100 can be implemented in an automated manner, resulting in reproducible tinted spectacle lens substrates 1. It can be easily integrated into existing production schemes. No pretreatment of the spectacle lens substrate 1 is required and no primer coating is required, so that the number of method steps can be kept low. Advantageously, the same tinting can be obtained on different spectacle lens substrates without variations.

[0191] Any type of spectacle lens substrate 1, such as disc, edged, etc., can be tinted on one or both sides, ie the proposed method 100 enables tinting of only one side of the spectacle lens substrate 1. Furthermore, non-linear color gradients can be formed.

[0192] Preferred features of the present invention are:

[0193] 1. A method for in-substrate tinting of an eyeglass lens substrate, the method comprising the steps of providing an eyeglass lens substrate comprising a polymer lens material, providing a composition comprising a polymer carrier material, applying a pattern of the composition onto a surface of the eyeglass lens substrate, and heating the eyeglass lens substrate to diffuse a dye substance between the carrier material and the lens material.

[0194] 2. The method of clause 1, further comprising removing the composition from the surface of the eyeglass lens substrate.

[0195] 3. The method of clause 1 or clause 2, wherein the composition comprises the dye substance contained in the carrier material, and wherein the dye substance is transferred from the carrier material to the lens material by diffusion.

[0196] 4. The method of clause 3, wherein the composition comprises a saturated dye-loaded carrier material.

[0197] 5. The method of any one of clauses 1 to 4, wherein the lens material comprises a dye substance and the dye substance is transferred from the lens material to the carrier material by diffusion.

[0198] 6. The method of any one of clauses 1 to 5, wherein the pattern of the composition is applied directly to the surface of the ophthalmic lens substrate.

[0199] 7. The method according to any one of clauses 1 to 6, wherein the method is performed in such a way that a coloring gradient is obtained.

[0200] 8. A method as described in any of clauses 1 to 7, wherein the freezing point Tc(carrier) of the carrier material is higher than the glass transition temperature Tg(lens) of the lens material, and wherein the spectacle lens substrate is heated to a temperature higher than the glass transition temperature Tg(lens) of the lens material and lower than the freezing point Tc(carrier) of the carrier material.

[0201] 9. A method as described in any of clauses 1 to 8, comprising the steps of providing a masking agent, applying a pattern of the masking agent on the surface of the spectacle lens substrate to obtain a partially masked spectacle lens substrate, immersing the partially masked spectacle lens substrate in a tinting bath containing a dye substance to tint the unshielded areas of the partially masked spectacle lens substrate, and removing the tinted, partially masked spectacle lens substrate from the tinting bath and removing the masking agent from the surface of the tinted, partially masked spectacle lens substrate.

[0202] 10. The method of clause 9, wherein the shielding agent is the composition comprising the carrier material.

[0203] 11. The method of any one of clauses 1 to 10, wherein the pattern is applied by inkjet printing.

[0204] 12. The method of any one of clauses 1 to 11, wherein the carrier material comprises at least one material selected from the group consisting of oxidized polyethylene wax, non-oxidized polyethylene wax, oxidized polypropylene wax and non-oxidized polypropylene wax.

[0205] 13. The method of any one of clauses 1 to 12, wherein transfer of the dye substance from / into the lens material occurs solely by diffusion.

[0206] 14. The method of any one of clauses 1 to 13, wherein the heating is performed before and / or after applying the pattern of the composition.

[0207] 15. The method of any one of clauses 1 to 14, wherein locally resolved intra-substrate coloration is obtained.

[0208] 16. A method as described in any one of clauses 1 to 15, comprising the steps of providing a carrier material and a dye substance, heating the carrier material to above its freezing point, dissolving the dye substance in the molten carrier material to obtain a dye-loaded carrier material, and cooling the dye-loaded carrier material to room temperature.

[0209] 17. The method according to clause 16, wherein the dye substance is dissolved in the molten carrier until saturation to obtain a saturated dye-loaded carrier material.

[0210] 18. The method of clause 16 or clause 17, wherein the solution of the dye carrier is filtered to remove any dye particles.

[0211] 19. The method of any one of clauses 3 to 18, wherein the composition exhibits a concentration of the dye species that is uniform throughout the composition.

[0212] 20. An ophthalmic lens substrate having an in-substrate tinting obtainable by one of the above methods.

[0213] 21. A composition for in-substrate tinting of a polymeric ophthalmic lens substrate, the composition comprising a dye-loaded carrier material, wherein the carrier material comprises at least one material selected from the group consisting of oxidized polyethylene wax, non-oxidized polyethylene wax, oxidized polypropylene wax, and non-oxidized polypropylene wax.

[0214] 22. The composition of clause 21, wherein the composition allows for transfer of dye substances from the carrier material to the lens material by diffusion after application of the composition to the surface of an ophthalmic lens substrate comprising a polymeric lens material.

[0215] 23. The composition of Clause 21 or Clause 22, wherein the dye-loaded carrier material is a saturated dye-loaded carrier material.

[0216] 24. The composition of any one of clauses 21 to 23, wherein the composition exhibits a concentration of the dye species that is uniform throughout the composition.

[0217] 25. An ophthalmic lens substrate comprising a polymeric lens material, wherein the ophthalmic lens substrate exhibits a pattern of a composition comprising a polymeric carrier material applied to a surface of the ophthalmic lens substrate.

[0218] 26. The eyeglass lens substrate of Clause 25, wherein the pattern of the composition is applied directly onto the surface of the eyeglass lens substrate.

[0219] 27. An ophthalmic lens substrate as described in Clause 25 or Clause 26, wherein the composition comprises a dye substance contained in the carrier material.

[0220] 28. An eyeglass lens substrate according to any of clauses 25 to 27, wherein the pattern is a locally resolved intra-substrate coloration.

[0221] 29. The spectacle lens substrate of any of clauses 25 to 28, wherein the freezing point Tc(support) of the polymer carrier material is higher than the glass transition temperature Tg(lens) of the polymer lens material.

[0222] 30. The spectacle lens substrate of any one of clauses 25 to 29, wherein the carrier material comprises at least one material selected from the group consisting of oxidized polyethylene wax, non-oxidized polyethylene wax, oxidized polypropylene wax and non-oxidized polypropylene wax.

[0223] 31. An ophthalmic lens substrate as described in any of clauses 25 to 30, wherein the polymeric carrier material is a saturated dye loaded carrier material.

[0224] 32. A spectacle lens substrate as described in any of clauses 25 to 31, wherein the lens material comprises a dye substance.

[0225] 33. The spectacle lens substrate of any of clauses 25 to 32, wherein the spectacle lens substrate exhibits a pattern of an obscuring agent.

[0226] 34. The ophthalmic lens substrate of Item 33, wherein the shielding agent is the composition comprising the carrier material.

[0227] 35. An eyeglass lens substrate as described in any of clauses 25 to 34, wherein the composition allows transfer of dye substances from the carrier material to the polymer lens material and / or transfer of dye substances from the lens material to the carrier material by diffusion upon heating of the eyeglass lens substrate.

[0228] 36. An ophthalmic lens substrate as described in any of clauses 27 to 35, wherein the composition exhibits a concentration of the dye substance that is uniform throughout the composition.

[0229] 37. An ophthalmic lens substrate comprising a polymeric lens material, wherein the ophthalmic lens substrate exhibits a pattern of the composition of any of clauses 21 to 24.

[0230] List of Reference Numerals

[0231] 1. Eyeglass lens substrate

[0232] 2 Lens materials

[0233] 3 Composition

[0234] 4 Carrier materials

[0235] 5 Pattern

[0236] 6 Surface

[0237] 7 Dye substances

[0238] 8. Masking Agent

[0239] 9 Partially shading eyeglass lens substrates

[0240] 10 Coloring Bath

[0241] 11 Unshielded Area

[0242] 12 Bleaching Area

[0243] 100, 200 Method

[0244] [A] Concentration of dye substance in carrier material

[0245] [B] Concentration of dye substances in lens materials

[0246] [W] Concentration of dye substance in the dye reservoir

[0247] T Temperature

[0248] t time

[0249] S1 to S13 Method steps

[0250] Tc(carrier) Condensation point of carrier material

[0251] Tg(lens) Glass transition temperature of the lens material

[0252] T1, T2, T3 time periods

Claims

1. A method (100) for in - substrate coloring of a spectacle lens substrate (1), the method (100) comprises the following steps: - S1: Providing a spectacle lens substrate (1) comprising a polymeric lens material (2), - S2: Providing a composition (3) comprising a polymeric carrier material (4), - S3: Applying a pattern (5) of the composition (3) onto the surface (6) of the spectacle lens substrate (1), and - S4: Heating the spectacle lens substrate (1) to allow a dye substance (7) to diffuse between the carrier material (4) and the lens material (2), wherein the lens material (2) contains the dye substance (7) and the dye substance (7) is transferred from the lens material (2) to the carrier material (4) by diffusion.

2. The method (100) according to claim 1, wherein, the composition (3) comprises a dye substance (7) contained in the carrier material (4), and wherein the dye substance (7) is transferred from the carrier material (4) to the lens material (2) by diffusion.

3. The method (100) according to claim 2, wherein, the composition (3) exhibits a uniform concentration of the dye substance (7) throughout the composition (3).

4. The method (100) according to any one of claims 1 to 3, wherein, the composition (3) comprises a saturated dye - loaded carrier material (4, 7).

5. The method (100) according to any one of claims 1 to 3, wherein, the pattern (5) of the composition (3) is directly applied onto the surface (6) of the spectacle lens substrate (1).

6. The method (100) according to any one of claims 1 to 3, wherein, the condensation point Tc (carrier) of the carrier material (4) is higher than the glass transition temperature Tg (lens) of the lens material (2).

7. The method (100) according to any one of claims 1 to 3, wherein, the spectacle lens substrate (1) is heated to a temperature higher than the glass transition temperature Tg (lens) of the lens material (2) and lower than the condensation point Tc (carrier) of the carrier material (4).

8. The method (100) according to any one of claims 1 to 3, the method comprises the following steps: - S6: Providing a masking agent (8), - S7: Applying a pattern (5) of the masking agent (8) onto the surface (6) of the spectacle lens substrate (1) to obtain a partially masked spectacle lens substrate (9), - S8: Immersing the partially masked spectacle lens substrate (9) in a coloring bath (10) containing a dye substance (7) to allow coloring of the unmasked area (11) of the partially masked spectacle lens substrate (9), and - S9: Removing the colored, partially masked spectacle lens substrate (9) from the coloring bath (10) and removing the masking agent (8) from the surface (6) of the colored, partially masked spectacle lens substrate (9).

9. The method (100) according to claim 8, wherein, the masking agent (8) is the composition (3) comprising the carrier material (4).

10. The method (100) according to any one of claims 1 to 3, in, The pattern (5) is applied by inkjet printing.

11. The method (100) according to any one of claims 1 to 3, comprising preparing the composition (3) according to the following steps: - S10: providing a carrier material (4) and a dye substance (7), - S11: heating the support material (4) to a temperature above its freezing point Tc(support), - S12: dissolving the dye substance (7) in the molten carrier material (4) to obtain a dye-loaded carrier material (4, 7), and - S13: The dye-loaded support material (4, 7) is cooled to room temperature.

12. The method (100) according to any one of claims 1 to 3, in, The carrier material (4) comprises at least one material selected from the group consisting of oxidized polyethylene wax, non-oxidized polyethylene wax, oxidized polypropylene wax and non-oxidized polypropylene wax.

13. An eyeglass lens substrate (1) comprising a polymer lens material (2) comprising a dye substance (7), wherein the eyeglass lens substrate (1) exhibits a pattern (5) of a composition (3) comprising a polymer carrier material (4) applied to a surface (6) of the eyeglass lens substrate (1), the carrier material (4) comprising at least one material selected from the group consisting of: oxidized polyethylene wax, non-oxidized polyethylene wax, oxidized polypropylene wax and non-oxidized polypropylene wax, wherein the composition (3) allows the dye substance (7) to be transferred from the lens material (2) to the carrier material (4) by diffusion when the eyeglass lens substrate (1) is heated.

14. The spectacle lens substrate (1) according to claim 13, in, The composition (3) allows the transfer of dye substances (7) from the carrier material (4) to the polymeric lens material (2) by diffusion upon heating of the spectacle lens substrate (1).

15. The spectacle lens substrate (1) according to claim 14, in, The composition (3) comprises a dye substance (7) contained in the carrier material (4).

16. The spectacle lens substrate (1) according to claim 15, in, The composition (3) exhibits a uniform concentration of the dye substance (7) throughout the composition (3).

17. The spectacle lens substrate (1) according to any one of claims 13 to 16, in, The coagulation point Tc(carrier) of the polymer carrier material (4) is higher than the glass transition temperature Tg(lens) of the polymer lens material (2).

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